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media fixes for v4.9-rc4 

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Merge tag 'media/v4.9-3' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media into synaptics-rmi4

Sync up with media tree to bring up latest Synaptics and Atmel changes.
This commit is contained in:
Dmitry Torokhov 2016-11-07 16:35:10 -08:00
parent c8d2bc9bc3 1aeb5b615c
commit d27625c9d5
851 changed files with 44105 additions and 51479 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

26
Documentation/CodingStyle
View File

@ -396,9 +396,13 @@ locations and some common work such as cleanup has to be done. If there is no
cleanup needed then just return directly.
Choose label names which say what the goto does or why the goto exists. An
example of a good name could be "out_buffer:" if the goto frees "buffer". Avoid
using GW-BASIC names like "err1:" and "err2:". Also don't name them after the
goto location like "err_kmalloc_failed:"
example of a good name could be "out_free_buffer:" if the goto frees "buffer".
Avoid using GW-BASIC names like "err1:" and "err2:", as you would have to
renumber them if you ever add or remove exit paths, and they make correctness
difficult to verify anyway.
It is advised to indent labels with a single space (not tab), so that
"diff -p" does not confuse labels with functions.
The rationale for using gotos is:
@ -425,7 +429,7 @@ The rationale for using gotos is:
goto out_buffer;
}
...
out_buffer:
out_free_buffer:
kfree(buffer);
return result;
}
@ -438,7 +442,16 @@ A common type of bug to be aware of is "one err bugs" which look like this:
return ret;
The bug in this code is that on some exit paths "foo" is NULL. Normally the
fix for this is to split it up into two error labels "err_bar:" and "err_foo:".
fix for this is to split it up into two error labels "err_free_bar:" and
"err_free_foo:":
err_free_bar:
kfree(foo->bar);
err_free_foo:
kfree(foo);
return ret;
Ideally you should simulate errors to test all exit paths.
Chapter 8: Commenting
@ -461,9 +474,6 @@ When commenting the kernel API functions, please use the kernel-doc format.
See the files Documentation/kernel-documentation.rst and scripts/kernel-doc
for details.
Linux style for comments is the C89 "/* ... */" style.
Don't use C99-style "// ..." comments.
The preferred style for long (multi-line) comments is:
/*

6
Documentation/DMA-API-HOWTO.txt
View File

@ -931,10 +931,8 @@ to "Closing".
1) Struct scatterlist requirements.
Don't invent the architecture specific struct scatterlist; just use
<asm-generic/scatterlist.h>. You need to enable
CONFIG_NEED_SG_DMA_LENGTH if the architecture supports IOMMUs
(including software IOMMU).
You need to enable CONFIG_NEED_SG_DMA_LENGTH if the architecture
supports IOMMUs (including software IOMMU).
2) ARCH_DMA_MINALIGN

12
Documentation/DocBook/Makefile
View File

@ -6,7 +6,7 @@
# To add a new book the only step required is to add the book to the
# list of DOCBOOKS.
DOCBOOKS := z8530book.xml device-drivers.xml \
DOCBOOKS := z8530book.xml \
kernel-hacking.xml kernel-locking.xml deviceiobook.xml \
writing_usb_driver.xml networking.xml \
kernel-api.xml filesystems.xml lsm.xml usb.xml kgdb.xml \
@ -22,8 +22,14 @@ ifeq ($(DOCBOOKS),)
# Skip DocBook build if the user explicitly requested no DOCBOOKS.
.DEFAULT:
@echo " SKIP DocBook $@ target (DOCBOOKS=\"\" specified)."
else
ifneq ($(SPHINXDIRS),)
# Skip DocBook build if the user explicitly requested a sphinx dir
.DEFAULT:
@echo " SKIP DocBook $@ target (SPHINXDIRS specified)."
else
###
# The build process is as follows (targets):
@ -66,6 +72,7 @@ installmandocs: mandocs
# no-op for the DocBook toolchain
epubdocs:
latexdocs:
###
#External programs used
@ -221,6 +228,7 @@ silent_gen_xml = :
echo "</programlisting>") > $@
endif # DOCBOOKS=""
endif # SPHINDIR=...
###
# Help targets as used by the top-level makefile

521
Documentation/DocBook/device-drivers.tmpl
View File

@ -1,521 +0,0 @@
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>
<book id="LinuxDriversAPI">
<bookinfo>
<title>Linux Device Drivers</title>
<legalnotice>
<para>
This documentation is free software; you can redistribute
it and/or modify it under the terms of the GNU General Public
License as published by the Free Software Foundation; either
version 2 of the License, or (at your option) any later
version.
</para>
<para>
This program is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied
warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See the GNU General Public License for more details.
</para>
<para>
You should have received a copy of the GNU General Public
License along with this program; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
MA 02111-1307 USA
</para>
<para>
For more details see the file COPYING in the source
distribution of Linux.
</para>
</legalnotice>
</bookinfo>
<toc></toc>
<chapter id="Basics">
<title>Driver Basics</title>
<sect1><title>Driver Entry and Exit points</title>
!Iinclude/linux/init.h
</sect1>
<sect1><title>Atomic and pointer manipulation</title>
!Iarch/x86/include/asm/atomic.h
</sect1>
<sect1><title>Delaying, scheduling, and timer routines</title>
!Iinclude/linux/sched.h
!Ekernel/sched/core.c
!Ikernel/sched/cpupri.c
!Ikernel/sched/fair.c
!Iinclude/linux/completion.h
!Ekernel/time/timer.c
</sect1>
<sect1><title>Wait queues and Wake events</title>
!Iinclude/linux/wait.h
!Ekernel/sched/wait.c
</sect1>
<sect1><title>High-resolution timers</title>
!Iinclude/linux/ktime.h
!Iinclude/linux/hrtimer.h
!Ekernel/time/hrtimer.c
</sect1>
<sect1><title>Workqueues and Kevents</title>
!Iinclude/linux/workqueue.h
!Ekernel/workqueue.c
</sect1>
<sect1><title>Internal Functions</title>
!Ikernel/exit.c
!Ikernel/signal.c
!Iinclude/linux/kthread.h
!Ekernel/kthread.c
</sect1>
<sect1><title>Kernel objects manipulation</title>
<!--
X!Iinclude/linux/kobject.h
-->
!Elib/kobject.c
</sect1>
<sect1><title>Kernel utility functions</title>
!Iinclude/linux/kernel.h
!Ekernel/printk/printk.c
!Ekernel/panic.c
!Ekernel/sys.c
!Ekernel/rcu/srcu.c
!Ekernel/rcu/tree.c
!Ekernel/rcu/tree_plugin.h
!Ekernel/rcu/update.c
</sect1>
<sect1><title>Device Resource Management</title>
!Edrivers/base/devres.c
</sect1>
</chapter>
<chapter id="devdrivers">
<title>Device drivers infrastructure</title>
<sect1><title>The Basic Device Driver-Model Structures </title>
!Iinclude/linux/device.h
</sect1>
<sect1><title>Device Drivers Base</title>
!Idrivers/base/init.c
!Edrivers/base/driver.c
!Edrivers/base/core.c
!Edrivers/base/syscore.c
!Edrivers/base/class.c
!Idrivers/base/node.c
!Edrivers/base/firmware_class.c
!Edrivers/base/transport_class.c
<!-- Cannot be included, because
attribute_container_add_class_device_adapter
and attribute_container_classdev_to_container
exceed allowed 44 characters maximum
X!Edrivers/base/attribute_container.c
-->
!Edrivers/base/dd.c
<!--
X!Edrivers/base/interface.c
-->
!Iinclude/linux/platform_device.h
!Edrivers/base/platform.c
!Edrivers/base/bus.c
</sect1>
<sect1>
<title>Buffer Sharing and Synchronization</title>
<para>
The dma-buf subsystem provides the framework for sharing buffers
for hardware (DMA) access across multiple device drivers and
subsystems, and for synchronizing asynchronous hardware access.
</para>
<para>
This is used, for example, by drm "prime" multi-GPU support, but
is of course not limited to GPU use cases.
</para>
<para>
The three main components of this are: (1) dma-buf, representing
a sg_table and exposed to userspace as a file descriptor to allow
passing between devices, (2) fence, which provides a mechanism
to signal when one device as finished access, and (3) reservation,
which manages the shared or exclusive fence(s) associated with
the buffer.
</para>
<sect2><title>dma-buf</title>
!Edrivers/dma-buf/dma-buf.c
!Iinclude/linux/dma-buf.h
</sect2>
<sect2><title>reservation</title>
!Pdrivers/dma-buf/reservation.c Reservation Object Overview
!Edrivers/dma-buf/reservation.c
!Iinclude/linux/reservation.h
</sect2>
<sect2><title>fence</title>
!Edrivers/dma-buf/fence.c
!Iinclude/linux/fence.h
!Edrivers/dma-buf/seqno-fence.c
!Iinclude/linux/seqno-fence.h
!Edrivers/dma-buf/fence-array.c
!Iinclude/linux/fence-array.h
!Edrivers/dma-buf/reservation.c
!Iinclude/linux/reservation.h
!Edrivers/dma-buf/sync_file.c
!Iinclude/linux/sync_file.h
</sect2>
</sect1>
<sect1><title>Device Drivers DMA Management</title>
!Edrivers/base/dma-coherent.c
!Edrivers/base/dma-mapping.c
</sect1>
<sect1><title>Device Drivers Power Management</title>
!Edrivers/base/power/main.c
</sect1>
<sect1><title>Device Drivers ACPI Support</title>
<!-- Internal functions only
X!Edrivers/acpi/sleep/main.c
X!Edrivers/acpi/sleep/wakeup.c
X!Edrivers/acpi/motherboard.c
X!Edrivers/acpi/bus.c
-->
!Edrivers/acpi/scan.c
!Idrivers/acpi/scan.c
<!-- No correct structured comments
X!Edrivers/acpi/pci_bind.c
-->
</sect1>
<sect1><title>Device drivers PnP support</title>
!Idrivers/pnp/core.c
<!-- No correct structured comments
X!Edrivers/pnp/system.c
-->
!Edrivers/pnp/card.c
!Idrivers/pnp/driver.c
!Edrivers/pnp/manager.c
!Edrivers/pnp/support.c
</sect1>
<sect1><title>Userspace IO devices</title>
!Edrivers/uio/uio.c
!Iinclude/linux/uio_driver.h
</sect1>
</chapter>
<chapter id="parportdev">
<title>Parallel Port Devices</title>
!Iinclude/linux/parport.h
!Edrivers/parport/ieee1284.c
!Edrivers/parport/share.c
!Idrivers/parport/daisy.c
</chapter>
<chapter id="message_devices">
<title>Message-based devices</title>
<sect1><title>Fusion message devices</title>
!Edrivers/message/fusion/mptbase.c
!Idrivers/message/fusion/mptbase.c
!Edrivers/message/fusion/mptscsih.c
!Idrivers/message/fusion/mptscsih.c
!Idrivers/message/fusion/mptctl.c
!Idrivers/message/fusion/mptspi.c
!Idrivers/message/fusion/mptfc.c
!Idrivers/message/fusion/mptlan.c
</sect1>
</chapter>
<chapter id="snddev">
<title>Sound Devices</title>
!Iinclude/sound/core.h
!Esound/sound_core.c
!Iinclude/sound/pcm.h
!Esound/core/pcm.c
!Esound/core/device.c
!Esound/core/info.c
!Esound/core/rawmidi.c
!Esound/core/sound.c
!Esound/core/memory.c
!Esound/core/pcm_memory.c
!Esound/core/init.c
!Esound/core/isadma.c
!Esound/core/control.c
!Esound/core/pcm_lib.c
!Esound/core/hwdep.c
!Esound/core/pcm_native.c
!Esound/core/memalloc.c
<!-- FIXME: Removed for now since no structured comments in source
X!Isound/sound_firmware.c
-->
</chapter>
<chapter id="uart16x50">
<title>16x50 UART Driver</title>
!Edrivers/tty/serial/serial_core.c
!Edrivers/tty/serial/8250/8250_core.c
</chapter>
<chapter id="fbdev">
<title>Frame Buffer Library</title>
<para>
The frame buffer drivers depend heavily on four data structures.
These structures are declared in include/linux/fb.h. They are
fb_info, fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs.
The last three can be made available to and from userland.
</para>
<para>
fb_info defines the current state of a particular video card.
Inside fb_info, there exists a fb_ops structure which is a
collection of needed functions to make fbdev and fbcon work.
fb_info is only visible to the kernel.
</para>
<para>
fb_var_screeninfo is used to describe the features of a video card
that are user defined. With fb_var_screeninfo, things such as
depth and the resolution may be defined.
</para>
<para>
The next structure is fb_fix_screeninfo. This defines the
properties of a card that are created when a mode is set and can't
be changed otherwise. A good example of this is the start of the
frame buffer memory. This "locks" the address of the frame buffer
memory, so that it cannot be changed or moved.
</para>
<para>
The last structure is fb_monospecs. In the old API, there was
little importance for fb_monospecs. This allowed for forbidden things
such as setting a mode of 800x600 on a fix frequency monitor. With
the new API, fb_monospecs prevents such things, and if used
correctly, can prevent a monitor from being cooked. fb_monospecs
will not be useful until kernels 2.5.x.
</para>
<sect1><title>Frame Buffer Memory</title>
!Edrivers/video/fbdev/core/fbmem.c
</sect1>
<!--
<sect1><title>Frame Buffer Console</title>
X!Edrivers/video/console/fbcon.c
</sect1>
-->
<sect1><title>Frame Buffer Colormap</title>
!Edrivers/video/fbdev/core/fbcmap.c
</sect1>
<!-- FIXME:
drivers/video/fbgen.c has no docs, which stuffs up the sgml. Comment
out until somebody adds docs. KAO
<sect1><title>Frame Buffer Generic Functions</title>
X!Idrivers/video/fbgen.c
</sect1>
KAO -->
<sect1><title>Frame Buffer Video Mode Database</title>
!Idrivers/video/fbdev/core/modedb.c
!Edrivers/video/fbdev/core/modedb.c
</sect1>
<sect1><title>Frame Buffer Macintosh Video Mode Database</title>
!Edrivers/video/fbdev/macmodes.c
</sect1>
<sect1><title>Frame Buffer Fonts</title>
<para>
Refer to the file lib/fonts/fonts.c for more information.
</para>
<!-- FIXME: Removed for now since no structured comments in source
X!Ilib/fonts/fonts.c
-->
</sect1>
</chapter>
<chapter id="input_subsystem">
<title>Input Subsystem</title>
<sect1><title>Input core</title>
!Iinclude/linux/input.h
!Edrivers/input/input.c
!Edrivers/input/ff-core.c
!Edrivers/input/ff-memless.c
</sect1>
<sect1><title>Multitouch Library</title>
!Iinclude/linux/input/mt.h
!Edrivers/input/input-mt.c
</sect1>
<sect1><title>Polled input devices</title>
!Iinclude/linux/input-polldev.h
!Edrivers/input/input-polldev.c
</sect1>
<sect1><title>Matrix keyboards/keypads</title>
!Iinclude/linux/input/matrix_keypad.h
</sect1>
<sect1><title>Sparse keymap support</title>
!Iinclude/linux/input/sparse-keymap.h
!Edrivers/input/sparse-keymap.c
</sect1>
</chapter>
<chapter id="spi">
<title>Serial Peripheral Interface (SPI)</title>
<para>
SPI is the "Serial Peripheral Interface", widely used with
embedded systems because it is a simple and efficient
interface: basically a multiplexed shift register.
Its three signal wires hold a clock (SCK, often in the range
of 1-20 MHz), a "Master Out, Slave In" (MOSI) data line, and
a "Master In, Slave Out" (MISO) data line.
SPI is a full duplex protocol; for each bit shifted out the
MOSI line (one per clock) another is shifted in on the MISO line.
Those bits are assembled into words of various sizes on the
way to and from system memory.
An additional chipselect line is usually active-low (nCS);
four signals are normally used for each peripheral, plus
sometimes an interrupt.
</para>
<para>
The SPI bus facilities listed here provide a generalized
interface to declare SPI busses and devices, manage them
according to the standard Linux driver model, and perform
input/output operations.
At this time, only "master" side interfaces are supported,
where Linux talks to SPI peripherals and does not implement
such a peripheral itself.
(Interfaces to support implementing SPI slaves would
necessarily look different.)
</para>
<para>
The programming interface is structured around two kinds of driver,
and two kinds of device.
A "Controller Driver" abstracts the controller hardware, which may
be as simple as a set of GPIO pins or as complex as a pair of FIFOs
connected to dual DMA engines on the other side of the SPI shift
register (maximizing throughput). Such drivers bridge between
whatever bus they sit on (often the platform bus) and SPI, and
expose the SPI side of their device as a
<structname>struct spi_master</structname>.
SPI devices are children of that master, represented as a
<structname>struct spi_device</structname> and manufactured from
<structname>struct spi_board_info</structname> descriptors which
are usually provided by board-specific initialization code.
A <structname>struct spi_driver</structname> is called a
"Protocol Driver", and is bound to a spi_device using normal
driver model calls.
</para>
<para>
The I/O model is a set of queued messages. Protocol drivers
submit one or more <structname>struct spi_message</structname>
objects, which are processed and completed asynchronously.
(There are synchronous wrappers, however.) Messages are
built from one or more <structname>struct spi_transfer</structname>
objects, each of which wraps a full duplex SPI transfer.
A variety of protocol tweaking options are needed, because
different chips adopt very different policies for how they
use the bits transferred with SPI.
</para>
!Iinclude/linux/spi/spi.h
!Fdrivers/spi/spi.c spi_register_board_info
!Edrivers/spi/spi.c
</chapter>
<chapter id="i2c">
<title>I<superscript>2</superscript>C and SMBus Subsystem</title>
<para>
I<superscript>2</superscript>C (or without fancy typography, "I2C")
is an acronym for the "Inter-IC" bus, a simple bus protocol which is
widely used where low data rate communications suffice.
Since it's also a licensed trademark, some vendors use another
name (such as "Two-Wire Interface", TWI) for the same bus.
I2C only needs two signals (SCL for clock, SDA for data), conserving
board real estate and minimizing signal quality issues.
Most I2C devices use seven bit addresses, and bus speeds of up
to 400 kHz; there's a high speed extension (3.4 MHz) that's not yet
found wide use.
I2C is a multi-master bus; open drain signaling is used to
arbitrate between masters, as well as to handshake and to
synchronize clocks from slower clients.
</para>
<para>
The Linux I2C programming interfaces support only the master
side of bus interactions, not the slave side.
The programming interface is structured around two kinds of driver,
and two kinds of device.
An I2C "Adapter Driver" abstracts the controller hardware; it binds
to a physical device (perhaps a PCI device or platform_device) and
exposes a <structname>struct i2c_adapter</structname> representing
each I2C bus segment it manages.
On each I2C bus segment will be I2C devices represented by a
<structname>struct i2c_client</structname>. Those devices will
be bound to a <structname>struct i2c_driver</structname>,
which should follow the standard Linux driver model.
(At this writing, a legacy model is more widely used.)
There are functions to perform various I2C protocol operations; at
this writing all such functions are usable only from task context.
</para>
<para>
The System Management Bus (SMBus) is a sibling protocol. Most SMBus
systems are also I2C conformant. The electrical constraints are
tighter for SMBus, and it standardizes particular protocol messages
and idioms. Controllers that support I2C can also support most
SMBus operations, but SMBus controllers don't support all the protocol
options that an I2C controller will.
There are functions to perform various SMBus protocol operations,
either using I2C primitives or by issuing SMBus commands to
i2c_adapter devices which don't support those I2C operations.
</para>
!Iinclude/linux/i2c.h
!Fdrivers/i2c/i2c-boardinfo.c i2c_register_board_info
!Edrivers/i2c/i2c-core.c
</chapter>
<chapter id="hsi">
<title>High Speed Synchronous Serial Interface (HSI)</title>
<para>
High Speed Synchronous Serial Interface (HSI) is a
serial interface mainly used for connecting application
engines (APE) with cellular modem engines (CMT) in cellular
handsets.
HSI provides multiplexing for up to 16 logical channels,
low-latency and full duplex communication.
</para>
!Iinclude/linux/hsi/hsi.h
!Edrivers/hsi/hsi_core.c
</chapter>
<chapter id="pwm">
<title>Pulse-Width Modulation (PWM)</title>
<para>
Pulse-width modulation is a modulation technique primarily used to
control power supplied to electrical devices.
</para>
<para>
The PWM framework provides an abstraction for providers and consumers
of PWM signals. A controller that provides one or more PWM signals is
registered as <structname>struct pwm_chip</structname>. Providers are
expected to embed this structure in a driver-specific structure. This
structure contains fields that describe a particular chip.
</para>
<para>
A chip exposes one or more PWM signal sources, each of which exposed
as a <structname>struct pwm_device</structname>. Operations can be
performed on PWM devices to control the period, duty cycle, polarity
and active state of the signal.
</para>
<para>
Note that PWM devices are exclusive resources: they can always only be
used by one consumer at a time.
</para>
!Iinclude/linux/pwm.h
!Edrivers/pwm/core.c
</chapter>
</book>

64
Documentation/Makefile.sphinx
View File

@ -5,6 +5,9 @@
# You can set these variables from the command line.
SPHINXBUILD = sphinx-build
SPHINXOPTS =
SPHINXDIRS = .
_SPHINXDIRS = $(patsubst $(srctree)/Documentation/%/conf.py,%,$(wildcard $(srctree)/Documentation/*/conf.py))
SPHINX_CONF = conf.py
PAPER =
BUILDDIR = $(obj)/output
@ -25,38 +28,62 @@ else ifneq ($(DOCBOOKS),)
else # HAVE_SPHINX
# User-friendly check for rst2pdf
HAVE_RST2PDF := $(shell if python -c "import rst2pdf" >/dev/null 2>&1; then echo 1; else echo 0; fi)
# User-friendly check for pdflatex
HAVE_PDFLATEX := $(shell if which xelatex >/dev/null 2>&1; then echo 1; else echo 0; fi)
# Internal variables.
PAPEROPT_a4 = -D latex_paper_size=a4
PAPEROPT_letter = -D latex_paper_size=letter
KERNELDOC = $(srctree)/scripts/kernel-doc
KERNELDOC_CONF = -D kerneldoc_srctree=$(srctree) -D kerneldoc_bin=$(KERNELDOC)
ALLSPHINXOPTS = -D version=$(KERNELVERSION) -D release=$(KERNELRELEASE) -d $(BUILDDIR)/.doctrees $(KERNELDOC_CONF) $(PAPEROPT_$(PAPER)) -c $(srctree)/$(src) $(SPHINXOPTS) $(srctree)/$(src)
ALLSPHINXOPTS = $(KERNELDOC_CONF) $(PAPEROPT_$(PAPER)) $(SPHINXOPTS)
# the i18n builder cannot share the environment and doctrees with the others
I18NSPHINXOPTS = $(PAPEROPT_$(PAPER)) $(SPHINXOPTS) .
quiet_cmd_sphinx = SPHINX $@
cmd_sphinx = BUILDDIR=$(BUILDDIR) $(SPHINXBUILD) -b $2 $(ALLSPHINXOPTS) $(BUILDDIR)/$2
# commands; the 'cmd' from scripts/Kbuild.include is not *loopable*
loop_cmd = $(echo-cmd) $(cmd_$(1))
# $2 sphinx builder e.g. "html"
# $3 name of the build subfolder / e.g. "media", used as:
# * dest folder relative to $(BUILDDIR) and
# * cache folder relative to $(BUILDDIR)/.doctrees
# $4 dest subfolder e.g. "man" for man pages at media/man
# $5 reST source folder relative to $(srctree)/$(src),
# e.g. "media" for the linux-tv book-set at ./Documentation/media
quiet_cmd_sphinx = SPHINX $@ --> file://$(abspath $(BUILDDIR)/$3/$4);
cmd_sphinx = $(MAKE) BUILDDIR=$(abspath $(BUILDDIR)) $(build)=Documentation/media all;\
BUILDDIR=$(abspath $(BUILDDIR)) SPHINX_CONF=$(abspath $(srctree)/$(src)/$5/$(SPHINX_CONF)) \
$(SPHINXBUILD) \
-b $2 \
-c $(abspath $(srctree)/$(src)) \
-d $(abspath $(BUILDDIR)/.doctrees/$3) \
-D version=$(KERNELVERSION) -D release=$(KERNELRELEASE) \
$(ALLSPHINXOPTS) \
$(abspath $(srctree)/$(src)/$5) \
$(abspath $(BUILDDIR)/$3/$4);
htmldocs:
$(MAKE) BUILDDIR=$(BUILDDIR) -f $(srctree)/Documentation/media/Makefile $@
$(call cmd,sphinx,html)
@$(foreach var,$(SPHINXDIRS),$(call loop_cmd,sphinx,html,$(var),,$(var)))
pdfdocs:
ifeq ($(HAVE_RST2PDF),0)
$(warning The Python 'rst2pdf' module was not found. Make sure you have the module installed to produce PDF output.)
latexdocs:
ifeq ($(HAVE_PDFLATEX),0)
$(warning The 'xelatex' command was not found. Make sure you have it installed and in PATH to produce PDF output.)
@echo " SKIP Sphinx $@ target."
else # HAVE_RST2PDF
$(call cmd,sphinx,pdf)
endif # HAVE_RST2PDF
else # HAVE_PDFLATEX
@$(foreach var,$(SPHINXDIRS),$(call loop_cmd,sphinx,latex,$(var),latex,$(var)))
endif # HAVE_PDFLATEX
pdfdocs: latexdocs
ifneq ($(HAVE_PDFLATEX),0)
$(foreach var,$(SPHINXDIRS), $(MAKE) PDFLATEX=xelatex LATEXOPTS="-interaction=nonstopmode" -C $(BUILDDIR)/$(var)/latex)
endif # HAVE_PDFLATEX
epubdocs:
$(call cmd,sphinx,epub)
@$(foreach var,$(SPHINXDIRS),$(call loop_cmd,sphinx,epub,$(var),epub,$(var)))
xmldocs:
$(call cmd,sphinx,xml)
@$(foreach var,$(SPHINXDIRS),$(call loop_cmd,sphinx,xml,$(var),xml,$(var)))
# no-ops for the Sphinx toolchain
sgmldocs:
@ -72,7 +99,14 @@ endif # HAVE_SPHINX
dochelp:
@echo ' Linux kernel internal documentation in different formats (Sphinx):'
@echo ' htmldocs - HTML'
@echo ' latexdocs - LaTeX'
@echo ' pdfdocs - PDF'
@echo ' epubdocs - EPUB'
@echo ' xmldocs - XML'
@echo ' cleandocs - clean all generated files'
@echo
@echo ' make SPHINXDIRS="s1 s2" [target] Generate only docs of folder s1, s2'
@echo ' valid values for SPHINXDIRS are: $(_SPHINXDIRS)'
@echo
@echo ' make SPHINX_CONF={conf-file} [target] use *additional* sphinx-build'
@echo ' configuration. This is e.g. useful to build with nit-picking config.'

11
Documentation/arm/sunxi/README
View File

@ -73,4 +73,13 @@ SunXi family
* Octa ARM Cortex-A7 based SoCs
- Allwinner A83T
+ Datasheet
http://dl.linux-sunxi.org/A83T/A83T_datasheet_Revision_1.1.pdf
https://github.com/allwinner-zh/documents/raw/master/A83T/A83T_Datasheet_v1.3_20150510.pdf
+ User Manual
https://github.com/allwinner-zh/documents/raw/master/A83T/A83T_User_Manual_v1.5.1_20150513.pdf
* Quad ARM Cortex-A53 based SoCs
- Allwinner A64
+ Datasheet
http://dl.linux-sunxi.org/A64/A64_Datasheet_V1.1.pdf
+ User Manual
http://dl.linux-sunxi.org/A64/Allwinner%20A64%20User%20Manual%20v1.0.pdf

42
Documentation/clk.txt
View File

@ -31,24 +31,25 @@ serve as a convenient shorthand for the implementation of the
hardware-specific bits for the hypothetical "foo" hardware.
Tying the two halves of this interface together is struct clk_hw, which
is defined in struct clk_foo and pointed to within struct clk. This
is defined in struct clk_foo and pointed to within struct clk_core. This
allows for easy navigation between the two discrete halves of the common
clock interface.
Part 2 - common data structures and api
Below is the common struct clk definition from
include/linux/clk-private.h, modified for brevity:
Below is the common struct clk_core definition from
drivers/clk/clk.c, modified for brevity:
struct clk {
struct clk_core {
const char *name;
const struct clk_ops *ops;
struct clk_hw *hw;
char **parent_names;
struct clk **parents;
struct clk *parent;
struct hlist_head children;
struct hlist_node child_node;
struct module *owner;
struct clk_core *parent;
const char **parent_names;
struct clk_core **parents;
u8 num_parents;
u8 new_parent_index;
...
};
@ -56,16 +57,19 @@ The members above make up the core of the clk tree topology. The clk
api itself defines several driver-facing functions which operate on
struct clk. That api is documented in include/linux/clk.h.
Platforms and devices utilizing the common struct clk use the struct
clk_ops pointer in struct clk to perform the hardware-specific parts of
the operations defined in clk.h:
Platforms and devices utilizing the common struct clk_core use the struct
clk_ops pointer in struct clk_core to perform the hardware-specific parts of
the operations defined in clk-provider.h:
struct clk_ops {
int (*prepare)(struct clk_hw *hw);
void (*unprepare)(struct clk_hw *hw);
int (*is_prepared)(struct clk_hw *hw);
void (*unprepare_unused)(struct clk_hw *hw);
int (*enable)(struct clk_hw *hw);
void (*disable)(struct clk_hw *hw);
int (*is_enabled)(struct clk_hw *hw);
void (*disable_unused)(struct clk_hw *hw);
unsigned long (*recalc_rate)(struct clk_hw *hw,
unsigned long parent_rate);
long (*round_rate)(struct clk_hw *hw,
@ -84,6 +88,8 @@ the operations defined in clk.h:
u8 index);
unsigned long (*recalc_accuracy)(struct clk_hw *hw,
unsigned long parent_accuracy);
int (*get_phase)(struct clk_hw *hw);
int (*set_phase)(struct clk_hw *hw, int degrees);
void (*init)(struct clk_hw *hw);
int (*debug_init)(struct clk_hw *hw,
struct dentry *dentry);
@ -91,7 +97,7 @@ the operations defined in clk.h:
Part 3 - hardware clk implementations
The strength of the common struct clk comes from its .ops and .hw pointers
The strength of the common struct clk_core comes from its .ops and .hw pointers
which abstract the details of struct clk from the hardware-specific bits, and
vice versa. To illustrate consider the simple gateable clk implementation in
drivers/clk/clk-gate.c:
@ -107,7 +113,7 @@ struct clk_gate contains struct clk_hw hw as well as hardware-specific
knowledge about which register and bit controls this clk's gating.
Nothing about clock topology or accounting, such as enable_count or
notifier_count, is needed here. That is all handled by the common
framework code and struct clk.
framework code and struct clk_core.
Let's walk through enabling this clk from driver code:
@ -139,22 +145,18 @@ static void clk_gate_set_bit(struct clk_gate *gate)
Note that to_clk_gate is defined as:
#define to_clk_gate(_hw) container_of(_hw, struct clk_gate, clk)
#define to_clk_gate(_hw) container_of(_hw, struct clk_gate, hw)
This pattern of abstraction is used for every clock hardware
representation.
Part 4 - supporting your own clk hardware
When implementing support for a new type of clock it only necessary to
When implementing support for a new type of clock it is only necessary to
include the following header:
#include <linux/clk-provider.h>
include/linux/clk.h is included within that header and clk-private.h
must never be included from the code which implements the operations for
a clock. More on that below in Part 5.
To construct a clk hardware structure for your platform you must define
the following:

104
Documentation/conf.py
View File

@ -14,11 +14,17 @@
import sys
import os
import sphinx
# Get Sphinx version
major, minor, patch = map(int, sphinx.__version__.split("."))
# If extensions (or modules to document with autodoc) are in another directory,
# add these directories to sys.path here. If the directory is relative to the
# documentation root, use os.path.abspath to make it absolute, like shown here.
sys.path.insert(0, os.path.abspath('sphinx'))
from load_config import loadConfig
# -- General configuration ------------------------------------------------
@ -28,14 +34,13 @@ sys.path.insert(0, os.path.abspath('sphinx'))
# Add any Sphinx extension module names here, as strings. They can be
# extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
# ones.
extensions = ['kernel-doc', 'rstFlatTable', 'kernel_include']
extensions = ['kernel-doc', 'rstFlatTable', 'kernel_include', 'cdomain']
# Gracefully handle missing rst2pdf.
try:
import rst2pdf
extensions += ['rst2pdf.pdfbuilder']
except ImportError:
pass
# The name of the math extension changed on Sphinx 1.4
if minor > 3:
extensions.append("sphinx.ext.imgmath")
else:
extensions.append("sphinx.ext.pngmath")
# Add any paths that contain templates here, relative to this directory.
templates_path = ['_templates']
@ -252,23 +257,90 @@ htmlhelp_basename = 'TheLinuxKerneldoc'
latex_elements = {
# The paper size ('letterpaper' or 'a4paper').
#'papersize': 'letterpaper',
'papersize': 'a4paper',
# The font size ('10pt', '11pt' or '12pt').
#'pointsize': '10pt',
# Additional stuff for the LaTeX preamble.
#'preamble': '',
'pointsize': '8pt',
# Latex figure (float) alignment
#'figure_align': 'htbp',
# Don't mangle with UTF-8 chars
'inputenc': '',
'utf8extra': '',
# Additional stuff for the LaTeX preamble.
'preamble': '''
% Adjust margins
\\usepackage[margin=0.5in, top=1in, bottom=1in]{geometry}
% Allow generate some pages in landscape
\\usepackage{lscape}
% Put notes in color and let them be inside a table
\\definecolor{NoteColor}{RGB}{204,255,255}
\\definecolor{WarningColor}{RGB}{255,204,204}
\\definecolor{AttentionColor}{RGB}{255,255,204}
\\definecolor{OtherColor}{RGB}{204,204,204}
\\newlength{\\mynoticelength}
\\makeatletter\\newenvironment{coloredbox}[1]{%
\\setlength{\\fboxrule}{1pt}
\\setlength{\\fboxsep}{7pt}
\\setlength{\\mynoticelength}{\\linewidth}
\\addtolength{\\mynoticelength}{-2\\fboxsep}
\\addtolength{\\mynoticelength}{-2\\fboxrule}
\\begin{lrbox}{\\@tempboxa}\\begin{minipage}{\\mynoticelength}}{\\end{minipage}\\end{lrbox}%
\\ifthenelse%
{\\equal{\\py@noticetype}{note}}%
{\\colorbox{NoteColor}{\\usebox{\\@tempboxa}}}%
{%
\\ifthenelse%
{\\equal{\\py@noticetype}{warning}}%
{\\colorbox{WarningColor}{\\usebox{\\@tempboxa}}}%
{%
\\ifthenelse%
{\\equal{\\py@noticetype}{attention}}%
{\\colorbox{AttentionColor}{\\usebox{\\@tempboxa}}}%
{\\colorbox{OtherColor}{\\usebox{\\@tempboxa}}}%
}%
}%
}\\makeatother
\\makeatletter
\\renewenvironment{notice}[2]{%
\\def\\py@noticetype{#1}
\\begin{coloredbox}{#1}
\\bf\\it
\\par\\strong{#2}
\\csname py@noticestart@#1\\endcsname
}
{
\\csname py@noticeend@\\py@noticetype\\endcsname
\\end{coloredbox}
}
\\makeatother
% Use some font with UTF-8 support with XeLaTeX
\\usepackage{fontspec}
\\setsansfont{DejaVu Serif}
\\setromanfont{DejaVu Sans}
\\setmonofont{DejaVu Sans Mono}
% To allow adjusting table sizes
\\usepackage{adjustbox}
'''
}
# Grouping the document tree into LaTeX files. List of tuples
# (source start file, target name, title,
# author, documentclass [howto, manual, or own class]).
latex_documents = [
(master_doc, 'TheLinuxKernel.tex', 'The Linux Kernel Documentation',
('kernel-documentation', 'kernel-documentation.tex', 'The Linux Kernel Documentation',
'The kernel development community', 'manual'),
('gpu/index', 'gpu.tex', 'Linux GPU Driver Developer\'s Guide',
'The kernel development community', 'manual'),
('media/index', 'media.tex', 'Linux Media Subsystem Documentation',
'The kernel development community', 'manual'),
]
@ -419,3 +491,9 @@ pdf_documents = [
# line arguments.
kerneldoc_bin = '../scripts/kernel-doc'
kerneldoc_srctree = '..'
# ------------------------------------------------------------------------------
# Since loadConfig overwrites settings from the global namespace, it has to be
# the last statement in the conf.py file
# ------------------------------------------------------------------------------
loadConfig(globals())

347
Documentation/coccinelle.txt → Documentation/dev-tools/coccinelle.rst
View File

@ -1,10 +1,18 @@
Copyright 2010 Nicolas Palix <npalix@diku.dk>
Copyright 2010 Julia Lawall <julia@diku.dk>
Copyright 2010 Gilles Muller <Gilles.Muller@lip6.fr>
.. Copyright 2010 Nicolas Palix <npalix@diku.dk>
.. Copyright 2010 Julia Lawall <julia@diku.dk>
.. Copyright 2010 Gilles Muller <Gilles.Muller@lip6.fr>
.. highlight:: none
Getting Coccinelle
~~~~~~~~~~~~~~~~~~~~
Coccinelle
==========
Coccinelle is a tool for pattern matching and text transformation that has
many uses in kernel development, including the application of complex,
tree-wide patches and detection of problematic programming patterns.
Getting Coccinelle
-------------------
The semantic patches included in the kernel use features and options
which are provided by Coccinelle version 1.0.0-rc11 and above.
@ -22,24 +30,23 @@ of many distributions, e.g. :
- NetBSD
- FreeBSD
You can get the latest version released from the Coccinelle homepage at
http://coccinelle.lip6.fr/
Information and tips about Coccinelle are also provided on the wiki
pages at http://cocci.ekstranet.diku.dk/wiki/doku.php
Once you have it, run the following command:
Once you have it, run the following command::
./configure
make
as a regular user, and install it with
as a regular user, and install it with::
sudo make install
Supplemental documentation
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Supplemental documentation
---------------------------
For supplemental documentation refer to the wiki:
@ -47,49 +54,52 @@ https://bottest.wiki.kernel.org/coccicheck
The wiki documentation always refers to the linux-next version of the script.
Using Coccinelle on the Linux kernel
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Using Coccinelle on the Linux kernel
------------------------------------
A Coccinelle-specific target is defined in the top level
Makefile. This target is named 'coccicheck' and calls the 'coccicheck'
front-end in the 'scripts' directory.
Makefile. This target is named ``coccicheck`` and calls the ``coccicheck``
front-end in the ``scripts`` directory.
Four basic modes are defined: patch, report, context, and org. The mode to
use is specified by setting the MODE variable with 'MODE=<mode>'.
Four basic modes are defined: ``patch``, ``report``, ``context``, and
``org``. The mode to use is specified by setting the MODE variable with
``MODE=<mode>``.
'patch' proposes a fix, when possible.
- ``patch`` proposes a fix, when possible.
'report' generates a list in the following format:
- ``report`` generates a list in the following format:
file:line:column-column: message
'context' highlights lines of interest and their context in a
diff-like style.Lines of interest are indicated with '-'.
- ``context`` highlights lines of interest and their context in a
diff-like style.Lines of interest are indicated with ``-``.
'org' generates a report in the Org mode format of Emacs.
- ``org`` generates a report in the Org mode format of Emacs.
Note that not all semantic patches implement all modes. For easy use
of Coccinelle, the default mode is "report".
Two other modes provide some common combinations of these modes.
'chain' tries the previous modes in the order above until one succeeds.
- ``chain`` tries the previous modes in the order above until one succeeds.
'rep+ctxt' runs successively the report mode and the context mode.
- ``rep+ctxt`` runs successively the report mode and the context mode.
It should be used with the C option (described later)
which checks the code on a file basis.
Examples:
To make a report for every semantic patch, run the following command:
Examples
~~~~~~~~
To make a report for every semantic patch, run the following command::
make coccicheck MODE=report
To produce patches, run:
To produce patches, run::
make coccicheck MODE=patch
The coccicheck target applies every semantic patch available in the
sub-directories of 'scripts/coccinelle' to the entire Linux kernel.
sub-directories of ``scripts/coccinelle`` to the entire Linux kernel.
For each semantic patch, a commit message is proposed. It gives a
description of the problem being checked by the semantic patch, and
@ -99,15 +109,15 @@ As any static code analyzer, Coccinelle produces false
positives. Thus, reports must be carefully checked, and patches
reviewed.
To enable verbose messages set the V= variable, for example:
To enable verbose messages set the V= variable, for example::
make coccicheck MODE=report V=1
Coccinelle parallelization
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Coccinelle parallelization
---------------------------
By default, coccicheck tries to run as parallel as possible. To change
the parallelism, set the J= variable. For example, to run across 4 CPUs:
the parallelism, set the J= variable. For example, to run across 4 CPUs::
make coccicheck MODE=report J=4
@ -115,44 +125,47 @@ As of Coccinelle 1.0.2 Coccinelle uses Ocaml parmap for parallelization,
if support for this is detected you will benefit from parmap parallelization.
When parmap is enabled coccicheck will enable dynamic load balancing by using
'--chunksize 1' argument, this ensures we keep feeding threads with work
``--chunksize 1`` argument, this ensures we keep feeding threads with work
one by one, so that we avoid the situation where most work gets done by only
a few threads. With dynamic load balancing, if a thread finishes early we keep
feeding it more work.
When parmap is enabled, if an error occurs in Coccinelle, this error
value is propagated back, the return value of the 'make coccicheck'
value is propagated back, the return value of the ``make coccicheck``
captures this return value.
Using Coccinelle with a single semantic patch
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Using Coccinelle with a single semantic patch
---------------------------------------------
The optional make variable COCCI can be used to check a single
semantic patch. In that case, the variable must be initialized with
the name of the semantic patch to apply.
For instance:
For instance::
make coccicheck COCCI=<my_SP.cocci> MODE=patch
or
or::
make coccicheck COCCI=<my_SP.cocci> MODE=report
Controlling Which Files are Processed by Coccinelle
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Controlling Which Files are Processed by Coccinelle
---------------------------------------------------
By default the entire kernel source tree is checked.
To apply Coccinelle to a specific directory, M= can be used.
For example, to check drivers/net/wireless/ one may write:
To apply Coccinelle to a specific directory, ``M=`` can be used.
For example, to check drivers/net/wireless/ one may write::
make coccicheck M=drivers/net/wireless/
To apply Coccinelle on a file basis, instead of a directory basis, the
following command may be used:
following command may be used::
make C=1 CHECK="scripts/coccicheck"
To check only newly edited code, use the value 2 for the C flag, i.e.
To check only newly edited code, use the value 2 for the C flag, i.e.::
make C=2 CHECK="scripts/coccicheck"
@ -166,8 +179,8 @@ semantic patch as shown in the previous section.
The "report" mode is the default. You can select another one with the
MODE variable explained above.
Debugging Coccinelle SmPL patches
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Debugging Coccinelle SmPL patches
---------------------------------
Using coccicheck is best as it provides in the spatch command line
include options matching the options used when we compile the kernel.
@ -177,8 +190,8 @@ manually run Coccinelle with debug options added.
Alternatively you can debug running Coccinelle against SmPL patches
by asking for stderr to be redirected to stderr, by default stderr
is redirected to /dev/null, if you'd like to capture stderr you
can specify the DEBUG_FILE="file.txt" option to coccicheck. For
instance:
can specify the ``DEBUG_FILE="file.txt"`` option to coccicheck. For
instance::
rm -f cocci.err
make coccicheck COCCI=scripts/coccinelle/free/kfree.cocci MODE=report DEBUG_FILE=cocci.err
@ -186,7 +199,7 @@ instance:
You can use SPFLAGS to add debugging flags, for instance you may want to
add both --profile --show-trying to SPFLAGS when debugging. For instance
you may want to use:
you may want to use::
rm -f err.log
export COCCI=scripts/coccinelle/misc/irqf_oneshot.cocci
@ -198,24 +211,24 @@ work.
DEBUG_FILE support is only supported when using coccinelle >= 1.2.
.cocciconfig support
~~~~~~~~~~~~~~~~~~~~~~
.cocciconfig support
--------------------
Coccinelle supports reading .cocciconfig for default Coccinelle options that
should be used every time spatch is spawned, the order of precedence for
variables for .cocciconfig is as follows:
o Your current user's home directory is processed first
o Your directory from which spatch is called is processed next
o The directory provided with the --dir option is processed last, if used
- Your current user's home directory is processed first
- Your directory from which spatch is called is processed next
- The directory provided with the --dir option is processed last, if used
Since coccicheck runs through make, it naturally runs from the kernel
proper dir, as such the second rule above would be implied for picking up a
.cocciconfig when using 'make coccicheck'.
.cocciconfig when using ``make coccicheck``.
'make coccicheck' also supports using M= targets.If you do not supply
``make coccicheck`` also supports using M= targets.If you do not supply
any M= target, it is assumed you want to target the entire kernel.
The kernel coccicheck script has:
The kernel coccicheck script has::
if [ "$KBUILD_EXTMOD" = "" ] ; then
OPTIONS="--dir $srctree $COCCIINCLUDE"
@ -235,12 +248,12 @@ override any of the kernel's .coccicheck's settings using SPFLAGS.
We help Coccinelle when used against Linux with a set of sensible defaults
options for Linux with our own Linux .cocciconfig. This hints to coccinelle
git can be used for 'git grep' queries over coccigrep. A timeout of 200
git can be used for ``git grep`` queries over coccigrep. A timeout of 200
seconds should suffice for now.
The options picked up by coccinelle when reading a .cocciconfig do not appear
as arguments to spatch processes running on your system, to confirm what
options will be used by Coccinelle run:
options will be used by Coccinelle run::
spatch --print-options-only
@ -252,219 +265,227 @@ carries its own .cocciconfig, you will need to use SPFLAGS to use idutils if
desired. See below section "Additional flags" for more details on how to use
idutils.
Additional flags
~~~~~~~~~~~~~~~~~~
Additional flags
----------------
Additional flags can be passed to spatch through the SPFLAGS
variable. This works as Coccinelle respects the last flags
given to it when options are in conflict.
given to it when options are in conflict. ::
make SPFLAGS=--use-glimpse coccicheck
Coccinelle supports idutils as well but requires coccinelle >= 1.0.6.
When no ID file is specified coccinelle assumes your ID database file
is in the file .id-utils.index on the top level of the kernel, coccinelle
carries a script scripts/idutils_index.sh which creates the database with
carries a script scripts/idutils_index.sh which creates the database with::
mkid -i C --output .id-utils.index
If you have another database filename you can also just symlink with this
name.
name. ::
make SPFLAGS=--use-idutils coccicheck
Alternatively you can specify the database filename explicitly, for
instance:
instance::
make SPFLAGS="--use-idutils /full-path/to/ID" coccicheck
See spatch --help to learn more about spatch options.
See ``spatch --help`` to learn more about spatch options.
Note that the '--use-glimpse' and '--use-idutils' options
Note that the ``--use-glimpse`` and ``--use-idutils`` options
require external tools for indexing the code. None of them is
thus active by default. However, by indexing the code with
one of these tools, and according to the cocci file used,
spatch could proceed the entire code base more quickly.
SmPL patch specific options
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SmPL patch specific options
---------------------------
SmPL patches can have their own requirements for options passed
to Coccinelle. SmPL patch specific options can be provided by
providing them at the top of the SmPL patch, for instance:
providing them at the top of the SmPL patch, for instance::
// Options: --no-includes --include-headers
// Options: --no-includes --include-headers
SmPL patch Coccinelle requirements
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
SmPL patch Coccinelle requirements
----------------------------------
As Coccinelle features get added some more advanced SmPL patches
may require newer versions of Coccinelle. If an SmPL patch requires
at least a version of Coccinelle, this can be specified as follows,
as an example if requiring at least Coccinelle >= 1.0.5:
as an example if requiring at least Coccinelle >= 1.0.5::
// Requires: 1.0.5
// Requires: 1.0.5
Proposing new semantic patches
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Proposing new semantic patches
-------------------------------
New semantic patches can be proposed and submitted by kernel
developers. For sake of clarity, they should be organized in the
sub-directories of 'scripts/coccinelle/'.
sub-directories of ``scripts/coccinelle/``.
Detailed description of the 'report' mode
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Detailed description of the ``report`` mode
-------------------------------------------
``report`` generates a list in the following format::
'report' generates a list in the following format:
file:line:column-column: message
Example:
Example
~~~~~~~
Running
Running::
make coccicheck MODE=report COCCI=scripts/coccinelle/api/err_cast.cocci
will execute the following part of the SmPL script.
will execute the following part of the SmPL script::
<smpl>
@r depends on !context && !patch && (org || report)@
expression x;
position p;
@@
<smpl>
@r depends on !context && !patch && (org || report)@
expression x;
position p;
@@
ERR_PTR@p(PTR_ERR(x))
@script:python depends on report@
p << r.p;
x << r.x;
@@
@script:python depends on report@
p << r.p;
x << r.x;
@@
msg="ERR_CAST can be used with %s" % (x)
coccilib.report.print_report(p[0], msg)
</smpl>
msg="ERR_CAST can be used with %s" % (x)
coccilib.report.print_report(p[0], msg)
</smpl>
This SmPL excerpt generates entries on the standard output, as
illustrated below:
illustrated below::
/home/user/linux/crypto/ctr.c:188:9-16: ERR_CAST can be used with alg
/home/user/linux/crypto/authenc.c:619:9-16: ERR_CAST can be used with auth
/home/user/linux/crypto/xts.c:227:9-16: ERR_CAST can be used with alg
/home/user/linux/crypto/ctr.c:188:9-16: ERR_CAST can be used with alg
/home/user/linux/crypto/authenc.c:619:9-16: ERR_CAST can be used with auth
/home/user/linux/crypto/xts.c:227:9-16: ERR_CAST can be used with alg
Detailed description of the 'patch' mode
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Detailed description of the ``patch`` mode
------------------------------------------
When the 'patch' mode is available, it proposes a fix for each problem
When the ``patch`` mode is available, it proposes a fix for each problem
identified.
Example:
Example
~~~~~~~
Running::
Running
make coccicheck MODE=patch COCCI=scripts/coccinelle/api/err_cast.cocci
will execute the following part of the SmPL script.
will execute the following part of the SmPL script::
<smpl>
@ depends on !context && patch && !org && !report @
expression x;
@@
<smpl>
@ depends on !context && patch && !org && !report @
expression x;
@@
- ERR_PTR(PTR_ERR(x))
+ ERR_CAST(x)
</smpl>
- ERR_PTR(PTR_ERR(x))
+ ERR_CAST(x)
</smpl>
This SmPL excerpt generates patch hunks on the standard output, as
illustrated below:
illustrated below::
diff -u -p a/crypto/ctr.c b/crypto/ctr.c
--- a/crypto/ctr.c 2010-05-26 10:49:38.000000000 +0200
+++ b/crypto/ctr.c 2010-06-03 23:44:49.000000000 +0200
@@ -185,7 +185,7 @@ static struct crypto_instance *crypto_ct
diff -u -p a/crypto/ctr.c b/crypto/ctr.c
--- a/crypto/ctr.c 2010-05-26 10:49:38.000000000 +0200
+++ b/crypto/ctr.c 2010-06-03 23:44:49.000000000 +0200
@@ -185,7 +185,7 @@ static struct crypto_instance *crypto_ct
alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,
CRYPTO_ALG_TYPE_MASK);
if (IS_ERR(alg))
- return ERR_PTR(PTR_ERR(alg));
+ return ERR_CAST(alg);
- return ERR_PTR(PTR_ERR(alg));
+ return ERR_CAST(alg);
/* Block size must be >= 4 bytes. */
err = -EINVAL;
Detailed description of the 'context' mode
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Detailed description of the ``context`` mode
--------------------------------------------
'context' highlights lines of interest and their context
``context`` highlights lines of interest and their context
in a diff-like style.
NOTE: The diff-like output generated is NOT an applicable patch. The
intent of the 'context' mode is to highlight the important lines
(annotated with minus, '-') and gives some surrounding context
**NOTE**: The diff-like output generated is NOT an applicable patch. The
intent of the ``context`` mode is to highlight the important lines
(annotated with minus, ``-``) and gives some surrounding context
lines around. This output can be used with the diff mode of
Emacs to review the code.
Example:
Example
~~~~~~~
Running::
Running
make coccicheck MODE=context COCCI=scripts/coccinelle/api/err_cast.cocci
will execute the following part of the SmPL script.
will execute the following part of the SmPL script::
<smpl>
@ depends on context && !patch && !org && !report@
expression x;
@@
<smpl>
@ depends on context && !patch && !org && !report@
expression x;
@@
* ERR_PTR(PTR_ERR(x))
</smpl>
* ERR_PTR(PTR_ERR(x))
</smpl>
This SmPL excerpt generates diff hunks on the standard output, as
illustrated below:
illustrated below::
diff -u -p /home/user/linux/crypto/ctr.c /tmp/nothing
--- /home/user/linux/crypto/ctr.c 2010-05-26 10:49:38.000000000 +0200
+++ /tmp/nothing
@@ -185,7 +185,6 @@ static struct crypto_instance *crypto_ct
diff -u -p /home/user/linux/crypto/ctr.c /tmp/nothing
--- /home/user/linux/crypto/ctr.c 2010-05-26 10:49:38.000000000 +0200
+++ /tmp/nothing
@@ -185,7 +185,6 @@ static struct crypto_instance *crypto_ct
alg = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER,
CRYPTO_ALG_TYPE_MASK);
if (IS_ERR(alg))
- return ERR_PTR(PTR_ERR(alg));
- return ERR_PTR(PTR_ERR(alg));
/* Block size must be >= 4 bytes. */
err = -EINVAL;
Detailed description of the 'org' mode
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Detailed description of the ``org`` mode
----------------------------------------
'org' generates a report in the Org mode format of Emacs.
``org`` generates a report in the Org mode format of Emacs.
Example:
Example
~~~~~~~
Running::
Running
make coccicheck MODE=org COCCI=scripts/coccinelle/api/err_cast.cocci
will execute the following part of the SmPL script.
will execute the following part of the SmPL script::
<smpl>
@r depends on !context && !patch && (org || report)@
expression x;
position p;
@@
<smpl>
@r depends on !context && !patch && (org || report)@
expression x;
position p;
@@
ERR_PTR@p(PTR_ERR(x))
@script:python depends on org@
p << r.p;
x << r.x;
@@
@script:python depends on org@
p << r.p;
x << r.x;
@@
msg="ERR_CAST can be used with %s" % (x)
msg_safe=msg.replace("[","@(").replace("]",")")
coccilib.org.print_todo(p[0], msg_safe)
</smpl>
msg="ERR_CAST can be used with %s" % (x)
msg_safe=msg.replace("[","@(").replace("]",")")
coccilib.org.print_todo(p[0], msg_safe)
</smpl>
This SmPL excerpt generates Org entries on the standard output, as
illustrated below:
illustrated below::
* TODO [[view:/home/user/linux/crypto/ctr.c::face=ovl-face1::linb=188::colb=9::cole=16][ERR_CAST can be used with alg]]
* TODO [[view:/home/user/linux/crypto/authenc.c::face=ovl-face1::linb=619::colb=9::cole=16][ERR_CAST can be used with auth]]
* TODO [[view:/home/user/linux/crypto/xts.c::face=ovl-face1::linb=227::colb=9::cole=16][ERR_CAST can be used with alg]]
* TODO [[view:/home/user/linux/crypto/ctr.c::face=ovl-face1::linb=188::colb=9::cole=16][ERR_CAST can be used with alg]]
* TODO [[view:/home/user/linux/crypto/authenc.c::face=ovl-face1::linb=619::colb=9::cole=16][ERR_CAST can be used with auth]]
* TODO [[view:/home/user/linux/crypto/xts.c::face=ovl-face1::linb=227::colb=9::cole=16][ERR_CAST can be used with alg]]

256
Documentation/dev-tools/gcov.rst Normal file
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@ -0,0 +1,256 @@
Using gcov with the Linux kernel
================================
gcov profiling kernel support enables the use of GCC's coverage testing
tool gcov_ with the Linux kernel. Coverage data of a running kernel
is exported in gcov-compatible format via the "gcov" debugfs directory.
To get coverage data for a specific file, change to the kernel build
directory and use gcov with the ``-o`` option as follows (requires root)::
# cd /tmp/linux-out
# gcov -o /sys/kernel/debug/gcov/tmp/linux-out/kernel spinlock.c
This will create source code files annotated with execution counts
in the current directory. In addition, graphical gcov front-ends such
as lcov_ can be used to automate the process of collecting data
for the entire kernel and provide coverage overviews in HTML format.
Possible uses:
* debugging (has this line been reached at all?)
* test improvement (how do I change my test to cover these lines?)
* minimizing kernel configurations (do I need this option if the
associated code is never run?)
.. _gcov: http://gcc.gnu.org/onlinedocs/gcc/Gcov.html
.. _lcov: http://ltp.sourceforge.net/coverage/lcov.php
Preparation
-----------
Configure the kernel with::
CONFIG_DEBUG_FS=y
CONFIG_GCOV_KERNEL=y
select the gcc's gcov format, default is autodetect based on gcc version::
CONFIG_GCOV_FORMAT_AUTODETECT=y
and to get coverage data for the entire kernel::
CONFIG_GCOV_PROFILE_ALL=y
Note that kernels compiled with profiling flags will be significantly
larger and run slower. Also CONFIG_GCOV_PROFILE_ALL may not be supported
on all architectures.
Profiling data will only become accessible once debugfs has been
mounted::
mount -t debugfs none /sys/kernel/debug
Customization
-------------
To enable profiling for specific files or directories, add a line
similar to the following to the respective kernel Makefile:
- For a single file (e.g. main.o)::
GCOV_PROFILE_main.o := y
- For all files in one directory::
GCOV_PROFILE := y
To exclude files from being profiled even when CONFIG_GCOV_PROFILE_ALL
is specified, use::
GCOV_PROFILE_main.o := n
and::
GCOV_PROFILE := n
Only files which are linked to the main kernel image or are compiled as
kernel modules are supported by this mechanism.
Files
-----
The gcov kernel support creates the following files in debugfs:
``/sys/kernel/debug/gcov``
Parent directory for all gcov-related files.
``/sys/kernel/debug/gcov/reset``
Global reset file: resets all coverage data to zero when
written to.
``/sys/kernel/debug/gcov/path/to/compile/dir/file.gcda``
The actual gcov data file as understood by the gcov
tool. Resets file coverage data to zero when written to.
``/sys/kernel/debug/gcov/path/to/compile/dir/file.gcno``
Symbolic link to a static data file required by the gcov
tool. This file is generated by gcc when compiling with
option ``-ftest-coverage``.
Modules
-------
Kernel modules may contain cleanup code which is only run during
module unload time. The gcov mechanism provides a means to collect
coverage data for such code by keeping a copy of the data associated
with the unloaded module. This data remains available through debugfs.
Once the module is loaded again, the associated coverage counters are
initialized with the data from its previous instantiation.
This behavior can be deactivated by specifying the gcov_persist kernel
parameter::
gcov_persist=0
At run-time, a user can also choose to discard data for an unloaded
module by writing to its data file or the global reset file.
Separated build and test machines
---------------------------------
The gcov kernel profiling infrastructure is designed to work out-of-the
box for setups where kernels are built and run on the same machine. In
cases where the kernel runs on a separate machine, special preparations
must be made, depending on where the gcov tool is used:
a) gcov is run on the TEST machine
The gcov tool version on the test machine must be compatible with the
gcc version used for kernel build. Also the following files need to be
copied from build to test machine:
from the source tree:
- all C source files + headers
from the build tree:
- all C source files + headers
- all .gcda and .gcno files
- all links to directories
It is important to note that these files need to be placed into the
exact same file system location on the test machine as on the build
machine. If any of the path components is symbolic link, the actual
directory needs to be used instead (due to make's CURDIR handling).
b) gcov is run on the BUILD machine
The following files need to be copied after each test case from test
to build machine:
from the gcov directory in sysfs:
- all .gcda files
- all links to .gcno files
These files can be copied to any location on the build machine. gcov
must then be called with the -o option pointing to that directory.
Example directory setup on the build machine::
/tmp/linux: kernel source tree
/tmp/out: kernel build directory as specified by make O=
/tmp/coverage: location of the files copied from the test machine
[user@build] cd /tmp/out
[user@build] gcov -o /tmp/coverage/tmp/out/init main.c
Troubleshooting
---------------
Problem
Compilation aborts during linker step.
Cause
Profiling flags are specified for source files which are not
linked to the main kernel or which are linked by a custom
linker procedure.
Solution
Exclude affected source files from profiling by specifying
``GCOV_PROFILE := n`` or ``GCOV_PROFILE_basename.o := n`` in the
corresponding Makefile.
Problem
Files copied from sysfs appear empty or incomplete.
Cause
Due to the way seq_file works, some tools such as cp or tar
may not correctly copy files from sysfs.
Solution
Use ``cat``' to read ``.gcda`` files and ``cp -d`` to copy links.
Alternatively use the mechanism shown in Appendix B.
Appendix A: gather_on_build.sh
------------------------------
Sample script to gather coverage meta files on the build machine
(see 6a)::
#!/bin/bash
KSRC=$1
KOBJ=$2
DEST=$3
if [ -z "$KSRC" ] || [ -z "$KOBJ" ] || [ -z "$DEST" ]; then
echo "Usage: $0 <ksrc directory> <kobj directory> <output.tar.gz>" >&2
exit 1
fi
KSRC=$(cd $KSRC; printf "all:\n\t@echo \${CURDIR}\n" | make -f -)
KOBJ=$(cd $KOBJ; printf "all:\n\t@echo \${CURDIR}\n" | make -f -)
find $KSRC $KOBJ \( -name '*.gcno' -o -name '*.[ch]' -o -type l \) -a \
-perm /u+r,g+r | tar cfz $DEST -P -T -
if [ $? -eq 0 ] ; then
echo "$DEST successfully created, copy to test system and unpack with:"
echo " tar xfz $DEST -P"
else
echo "Could not create file $DEST"
fi
Appendix B: gather_on_test.sh
-----------------------------
Sample script to gather coverage data files on the test machine
(see 6b)::
#!/bin/bash -e
DEST=$1
GCDA=/sys/kernel/debug/gcov
if [ -z "$DEST" ] ; then
echo "Usage: $0 <output.tar.gz>" >&2
exit 1
fi
TEMPDIR=$(mktemp -d)
echo Collecting data..
find $GCDA -type d -exec mkdir -p $TEMPDIR/\{\} \;
find $GCDA -name '*.gcda' -exec sh -c 'cat < $0 > '$TEMPDIR'/$0' {} \;
find $GCDA -name '*.gcno' -exec sh -c 'cp -d $0 '$TEMPDIR'/$0' {} \;
tar czf $DEST -C $TEMPDIR sys
rm -rf $TEMPDIR
echo "$DEST successfully created, copy to build system and unpack with:"
echo " tar xfz $DEST"

53
Documentation/gdb-kernel-debugging.txt → Documentation/dev-tools/gdb-kernel-debugging.rst
View File

@ -1,3 +1,5 @@
.. highlight:: none
Debugging kernel and modules via gdb
====================================
@ -13,54 +15,58 @@ be transferred to the other gdb stubs as well.
Requirements
------------
o gdb 7.2+ (recommended: 7.4+) with python support enabled (typically true
- gdb 7.2+ (recommended: 7.4+) with python support enabled (typically true
for distributions)
Setup
-----
o Create a virtual Linux machine for QEMU/KVM (see www.linux-kvm.org and
- Create a virtual Linux machine for QEMU/KVM (see www.linux-kvm.org and
www.qemu.org for more details). For cross-development,
http://landley.net/aboriginal/bin keeps a pool of machine images and
toolchains that can be helpful to start from.
o Build the kernel with CONFIG_GDB_SCRIPTS enabled, but leave
- Build the kernel with CONFIG_GDB_SCRIPTS enabled, but leave
CONFIG_DEBUG_INFO_REDUCED off. If your architecture supports
CONFIG_FRAME_POINTER, keep it enabled.
o Install that kernel on the guest.
- Install that kernel on the guest.
Alternatively, QEMU allows to boot the kernel directly using -kernel,
-append, -initrd command line switches. This is generally only useful if
you do not depend on modules. See QEMU documentation for more details on
this mode.
o Enable the gdb stub of QEMU/KVM, either
- Enable the gdb stub of QEMU/KVM, either
- at VM startup time by appending "-s" to the QEMU command line
or
- during runtime by issuing "gdbserver" from the QEMU monitor
console
o cd /path/to/linux-build
- cd /path/to/linux-build
o Start gdb: gdb vmlinux
- Start gdb: gdb vmlinux
Note: Some distros may restrict auto-loading of gdb scripts to known safe
directories. In case gdb reports to refuse loading vmlinux-gdb.py, add
directories. In case gdb reports to refuse loading vmlinux-gdb.py, add::
add-auto-load-safe-path /path/to/linux-build
to ~/.gdbinit. See gdb help for more details.
o Attach to the booted guest:
- Attach to the booted guest::
(gdb) target remote :1234
Examples of using the Linux-provided gdb helpers
------------------------------------------------
o Load module (and main kernel) symbols:
- Load module (and main kernel) symbols::
(gdb) lx-symbols
loading vmlinux
scanning for modules in /home/user/linux/build
@ -72,17 +78,20 @@ Examples of using the Linux-provided gdb helpers
...
loading @0xffffffffa0000000: /home/user/linux/build/drivers/ata/ata_generic.ko
o Set a breakpoint on some not yet loaded module function, e.g.:
- Set a breakpoint on some not yet loaded module function, e.g.::
(gdb) b btrfs_init_sysfs
Function "btrfs_init_sysfs" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (btrfs_init_sysfs) pending.
o Continue the target
- Continue the target::
(gdb) c
o Load the module on the target and watch the symbols being loaded as well as
the breakpoint hit:
- Load the module on the target and watch the symbols being loaded as well as
the breakpoint hit::
loading @0xffffffffa0034000: /home/user/linux/build/lib/libcrc32c.ko
loading @0xffffffffa0050000: /home/user/linux/build/lib/lzo/lzo_compress.ko
loading @0xffffffffa006e000: /home/user/linux/build/lib/zlib_deflate/zlib_deflate.ko
@ -91,7 +100,8 @@ Examples of using the Linux-provided gdb helpers
Breakpoint 1, btrfs_init_sysfs () at /home/user/linux/fs/btrfs/sysfs.c:36
36 btrfs_kset = kset_create_and_add("btrfs", NULL, fs_kobj);
o Dump the log buffer of the target kernel:
- Dump the log buffer of the target kernel::
(gdb) lx-dmesg
[ 0.000000] Initializing cgroup subsys cpuset
[ 0.000000] Initializing cgroup subsys cpu
@ -102,19 +112,22 @@ Examples of using the Linux-provided gdb helpers
[ 0.000000] BIOS-e820: [mem 0x000000000009fc00-0x000000000009ffff] reserved
....
o Examine fields of the current task struct:
- Examine fields of the current task struct::
(gdb) p $lx_current().pid
$1 = 4998
(gdb) p $lx_current().comm
$2 = "modprobe\000\000\000\000\000\000\000"
o Make use of the per-cpu function for the current or a specified CPU:
- Make use of the per-cpu function for the current or a specified CPU::
(gdb) p $lx_per_cpu("runqueues").nr_running
$3 = 1
(gdb) p $lx_per_cpu("runqueues", 2).nr_running
$4 = 0
o Dig into hrtimers using the container_of helper:
- Dig into hrtimers using the container_of helper::
(gdb) set $next = $lx_per_cpu("hrtimer_bases").clock_base[0].active.next
(gdb) p *$container_of($next, "struct hrtimer", "node")
$5 = {
@ -144,7 +157,7 @@ List of commands and functions
------------------------------
The number of commands and convenience functions may evolve over the time,
this is just a snapshot of the initial version:
this is just a snapshot of the initial version::
(gdb) apropos lx
function lx_current -- Return current task

173
Documentation/dev-tools/kasan.rst Normal file
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@ -0,0 +1,173 @@
The Kernel Address Sanitizer (KASAN)
====================================
Overview
--------
KernelAddressSANitizer (KASAN) is a dynamic memory error detector. It provides
a fast and comprehensive solution for finding use-after-free and out-of-bounds
bugs.
KASAN uses compile-time instrumentation for checking every memory access,
therefore you will need a GCC version 4.9.2 or later. GCC 5.0 or later is
required for detection of out-of-bounds accesses to stack or global variables.
Currently KASAN is supported only for the x86_64 and arm64 architectures.
Usage
-----
To enable KASAN configure kernel with::
CONFIG_KASAN = y
and choose between CONFIG_KASAN_OUTLINE and CONFIG_KASAN_INLINE. Outline and
inline are compiler instrumentation types. The former produces smaller binary
the latter is 1.1 - 2 times faster. Inline instrumentation requires a GCC
version 5.0 or later.
KASAN works with both SLUB and SLAB memory allocators.
For better bug detection and nicer reporting, enable CONFIG_STACKTRACE.
To disable instrumentation for specific files or directories, add a line
similar to the following to the respective kernel Makefile:
- For a single file (e.g. main.o)::
KASAN_SANITIZE_main.o := n
- For all files in one directory::
KASAN_SANITIZE := n
Error reports
~~~~~~~~~~~~~
A typical out of bounds access report looks like this::
==================================================================
BUG: AddressSanitizer: out of bounds access in kmalloc_oob_right+0x65/0x75 [test_kasan] at addr ffff8800693bc5d3
Write of size 1 by task modprobe/1689
=============================================================================
BUG kmalloc-128 (Not tainted): kasan error
-----------------------------------------------------------------------------
Disabling lock debugging due to kernel taint
INFO: Allocated in kmalloc_oob_right+0x3d/0x75 [test_kasan] age=0 cpu=0 pid=1689
__slab_alloc+0x4b4/0x4f0
kmem_cache_alloc_trace+0x10b/0x190
kmalloc_oob_right+0x3d/0x75 [test_kasan]
init_module+0x9/0x47 [test_kasan]
do_one_initcall+0x99/0x200
load_module+0x2cb3/0x3b20
SyS_finit_module+0x76/0x80
system_call_fastpath+0x12/0x17
INFO: Slab 0xffffea0001a4ef00 objects=17 used=7 fp=0xffff8800693bd728 flags=0x100000000004080
INFO: Object 0xffff8800693bc558 @offset=1368 fp=0xffff8800693bc720
Bytes b4 ffff8800693bc548: 00 00 00 00 00 00 00 00 5a 5a 5a 5a 5a 5a 5a 5a ........ZZZZZZZZ
Object ffff8800693bc558: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ffff8800693bc568: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ffff8800693bc578: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ffff8800693bc588: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ffff8800693bc598: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ffff8800693bc5a8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ffff8800693bc5b8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ffff8800693bc5c8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkkkkkkkkkk.
Redzone ffff8800693bc5d8: cc cc cc cc cc cc cc cc ........
Padding ffff8800693bc718: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ
CPU: 0 PID: 1689 Comm: modprobe Tainted: G B 3.18.0-rc1-mm1+ #98
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
ffff8800693bc000 0000000000000000 ffff8800693bc558 ffff88006923bb78
ffffffff81cc68ae 00000000000000f3 ffff88006d407600 ffff88006923bba8
ffffffff811fd848 ffff88006d407600 ffffea0001a4ef00 ffff8800693bc558
Call Trace:
[<ffffffff81cc68ae>] dump_stack+0x46/0x58
[<ffffffff811fd848>] print_trailer+0xf8/0x160
[<ffffffffa00026a7>] ? kmem_cache_oob+0xc3/0xc3 [test_kasan]
[<ffffffff811ff0f5>] object_err+0x35/0x40
[<ffffffffa0002065>] ? kmalloc_oob_right+0x65/0x75 [test_kasan]
[<ffffffff8120b9fa>] kasan_report_error+0x38a/0x3f0
[<ffffffff8120a79f>] ? kasan_poison_shadow+0x2f/0x40
[<ffffffff8120b344>] ? kasan_unpoison_shadow+0x14/0x40
[<ffffffff8120a79f>] ? kasan_poison_shadow+0x2f/0x40
[<ffffffffa00026a7>] ? kmem_cache_oob+0xc3/0xc3 [test_kasan]
[<ffffffff8120a995>] __asan_store1+0x75/0xb0
[<ffffffffa0002601>] ? kmem_cache_oob+0x1d/0xc3 [test_kasan]
[<ffffffffa0002065>] ? kmalloc_oob_right+0x65/0x75 [test_kasan]
[<ffffffffa0002065>] kmalloc_oob_right+0x65/0x75 [test_kasan]
[<ffffffffa00026b0>] init_module+0x9/0x47 [test_kasan]
[<ffffffff810002d9>] do_one_initcall+0x99/0x200
[<ffffffff811e4e5c>] ? __vunmap+0xec/0x160
[<ffffffff81114f63>] load_module+0x2cb3/0x3b20
[<ffffffff8110fd70>] ? m_show+0x240/0x240
[<ffffffff81115f06>] SyS_finit_module+0x76/0x80
[<ffffffff81cd3129>] system_call_fastpath+0x12/0x17
Memory state around the buggy address:
ffff8800693bc300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8800693bc380: fc fc 00 00 00 00 00 00 00 00 00 00 00 00 00 fc
ffff8800693bc400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8800693bc480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8800693bc500: fc fc fc fc fc fc fc fc fc fc fc 00 00 00 00 00
>ffff8800693bc580: 00 00 00 00 00 00 00 00 00 00 03 fc fc fc fc fc
^
ffff8800693bc600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8800693bc680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8800693bc700: fc fc fc fc fb fb fb fb fb fb fb fb fb fb fb fb
ffff8800693bc780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8800693bc800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
The header of the report discribe what kind of bug happened and what kind of
access caused it. It's followed by the description of the accessed slub object
(see 'SLUB Debug output' section in Documentation/vm/slub.txt for details) and
the description of the accessed memory page.
In the last section the report shows memory state around the accessed address.
Reading this part requires some understanding of how KASAN works.
The state of each 8 aligned bytes of memory is encoded in one shadow byte.
Those 8 bytes can be accessible, partially accessible, freed or be a redzone.
We use the following encoding for each shadow byte: 0 means that all 8 bytes
of the corresponding memory region are accessible; number N (1 <= N <= 7) means
that the first N bytes are accessible, and other (8 - N) bytes are not;
any negative value indicates that the entire 8-byte word is inaccessible.
We use different negative values to distinguish between different kinds of
inaccessible memory like redzones or freed memory (see mm/kasan/kasan.h).
In the report above the arrows point to the shadow byte 03, which means that
the accessed address is partially accessible.
Implementation details
----------------------
From a high level, our approach to memory error detection is similar to that
of kmemcheck: use shadow memory to record whether each byte of memory is safe
to access, and use compile-time instrumentation to check shadow memory on each
memory access.
AddressSanitizer dedicates 1/8 of kernel memory to its shadow memory
(e.g. 16TB to cover 128TB on x86_64) and uses direct mapping with a scale and
offset to translate a memory address to its corresponding shadow address.
Here is the function which translates an address to its corresponding shadow
address::
static inline void *kasan_mem_to_shadow(const void *addr)
{
return ((unsigned long)addr >> KASAN_SHADOW_SCALE_SHIFT)
+ KASAN_SHADOW_OFFSET;
}
where ``KASAN_SHADOW_SCALE_SHIFT = 3``.
Compile-time instrumentation used for checking memory accesses. Compiler inserts
function calls (__asan_load*(addr), __asan_store*(addr)) before each memory
access of size 1, 2, 4, 8 or 16. These functions check whether memory access is
valid or not by checking corresponding shadow memory.
GCC 5.0 has possibility to perform inline instrumentation. Instead of making
function calls GCC directly inserts the code to check the shadow memory.
This option significantly enlarges kernel but it gives x1.1-x2 performance
boost over outline instrumented kernel.

74
Documentation/kcov.txt → Documentation/dev-tools/kcov.rst
View File

@ -12,38 +12,38 @@ To achieve this goal it does not collect coverage in soft/hard interrupts
and instrumentation of some inherently non-deterministic parts of kernel is
disbled (e.g. scheduler, locking).
Usage:
======
Usage
-----
Configure kernel with:
Configure the kernel with::
CONFIG_KCOV=y
CONFIG_KCOV requires gcc built on revision 231296 or later.
Profiling data will only become accessible once debugfs has been mounted:
Profiling data will only become accessible once debugfs has been mounted::
mount -t debugfs none /sys/kernel/debug
The following program demonstrates kcov usage from within a test program:
The following program demonstrates kcov usage from within a test program::
#include <stdio.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <unistd.h>
#include <fcntl.h>
#define KCOV_INIT_TRACE _IOR('c', 1, unsigned long)
#define KCOV_ENABLE _IO('c', 100)
#define KCOV_DISABLE _IO('c', 101)
#define COVER_SIZE (64<<10)
#define KCOV_INIT_TRACE _IOR('c', 1, unsigned long)
#define KCOV_ENABLE _IO('c', 100)
#define KCOV_DISABLE _IO('c', 101)
#define COVER_SIZE (64<<10)
int main(int argc, char **argv)
{
int main(int argc, char **argv)
{
int fd;
unsigned long *cover, n, i;
@ -83,24 +83,24 @@ int main(int argc, char **argv)
if (close(fd))
perror("close"), exit(1);
return 0;
}
}
After piping through addr2line output of the program looks as follows:
After piping through addr2line output of the program looks as follows::
SyS_read
fs/read_write.c:562
__fdget_pos
fs/file.c:774
__fget_light
fs/file.c:746
__fget_light
fs/file.c:750
__fget_light
fs/file.c:760
__fdget_pos
fs/file.c:784
SyS_read
fs/read_write.c:562
SyS_read
fs/read_write.c:562
__fdget_pos
fs/file.c:774
__fget_light
fs/file.c:746
__fget_light
fs/file.c:750
__fget_light
fs/file.c:760
__fdget_pos
fs/file.c:784
SyS_read
fs/read_write.c:562
If a program needs to collect coverage from several threads (independently),
it needs to open /sys/kernel/debug/kcov in each thread separately.

733
Documentation/dev-tools/kmemcheck.rst Normal file
View File

@ -0,0 +1,733 @@
Getting started with kmemcheck
==============================
Vegard Nossum <vegardno@ifi.uio.no>
Introduction
------------
kmemcheck is a debugging feature for the Linux Kernel. More specifically, it
is a dynamic checker that detects and warns about some uses of uninitialized
memory.
Userspace programmers might be familiar with Valgrind's memcheck. The main
difference between memcheck and kmemcheck is that memcheck works for userspace
programs only, and kmemcheck works for the kernel only. The implementations
are of course vastly different. Because of this, kmemcheck is not as accurate
as memcheck, but it turns out to be good enough in practice to discover real
programmer errors that the compiler is not able to find through static
analysis.
Enabling kmemcheck on a kernel will probably slow it down to the extent that
the machine will not be usable for normal workloads such as e.g. an
interactive desktop. kmemcheck will also cause the kernel to use about twice
as much memory as normal. For this reason, kmemcheck is strictly a debugging
feature.
Downloading
-----------
As of version 2.6.31-rc1, kmemcheck is included in the mainline kernel.
Configuring and compiling
-------------------------
kmemcheck only works for the x86 (both 32- and 64-bit) platform. A number of
configuration variables must have specific settings in order for the kmemcheck
menu to even appear in "menuconfig". These are:
- ``CONFIG_CC_OPTIMIZE_FOR_SIZE=n``
This option is located under "General setup" / "Optimize for size".
Without this, gcc will use certain optimizations that usually lead to
false positive warnings from kmemcheck. An example of this is a 16-bit
field in a struct, where gcc may load 32 bits, then discard the upper
16 bits. kmemcheck sees only the 32-bit load, and may trigger a
warning for the upper 16 bits (if they're uninitialized).
- ``CONFIG_SLAB=y`` or ``CONFIG_SLUB=y``
This option is located under "General setup" / "Choose SLAB
allocator".
- ``CONFIG_FUNCTION_TRACER=n``
This option is located under "Kernel hacking" / "Tracers" / "Kernel
Function Tracer"
When function tracing is compiled in, gcc emits a call to another
function at the beginning of every function. This means that when the
page fault handler is called, the ftrace framework will be called
before kmemcheck has had a chance to handle the fault. If ftrace then
modifies memory that was tracked by kmemcheck, the result is an
endless recursive page fault.
- ``CONFIG_DEBUG_PAGEALLOC=n``
This option is located under "Kernel hacking" / "Memory Debugging"
/ "Debug page memory allocations".
In addition, I highly recommend turning on ``CONFIG_DEBUG_INFO=y``. This is also
located under "Kernel hacking". With this, you will be able to get line number
information from the kmemcheck warnings, which is extremely valuable in
debugging a problem. This option is not mandatory, however, because it slows
down the compilation process and produces a much bigger kernel image.
Now the kmemcheck menu should be visible (under "Kernel hacking" / "Memory
Debugging" / "kmemcheck: trap use of uninitialized memory"). Here follows
a description of the kmemcheck configuration variables:
- ``CONFIG_KMEMCHECK``
This must be enabled in order to use kmemcheck at all...
- ``CONFIG_KMEMCHECK_``[``DISABLED`` | ``ENABLED`` | ``ONESHOT``]``_BY_DEFAULT``
This option controls the status of kmemcheck at boot-time. "Enabled"
will enable kmemcheck right from the start, "disabled" will boot the
kernel as normal (but with the kmemcheck code compiled in, so it can
be enabled at run-time after the kernel has booted), and "one-shot" is
a special mode which will turn kmemcheck off automatically after
detecting the first use of uninitialized memory.
If you are using kmemcheck to actively debug a problem, then you
probably want to choose "enabled" here.
The one-shot mode is mostly useful in automated test setups because it
can prevent floods of warnings and increase the chances of the machine
surviving in case something is really wrong. In other cases, the one-
shot mode could actually be counter-productive because it would turn
itself off at the very first error -- in the case of a false positive
too -- and this would come in the way of debugging the specific
problem you were interested in.
If you would like to use your kernel as normal, but with a chance to
enable kmemcheck in case of some problem, it might be a good idea to
choose "disabled" here. When kmemcheck is disabled, most of the run-
time overhead is not incurred, and the kernel will be almost as fast
as normal.
- ``CONFIG_KMEMCHECK_QUEUE_SIZE``
Select the maximum number of error reports to store in an internal
(fixed-size) buffer. Since errors can occur virtually anywhere and in
any context, we need a temporary storage area which is guaranteed not
to generate any other page faults when accessed. The queue will be
emptied as soon as a tasklet may be scheduled. If the queue is full,
new error reports will be lost.
The default value of 64 is probably fine. If some code produces more
than 64 errors within an irqs-off section, then the code is likely to
produce many, many more, too, and these additional reports seldom give
any more information (the first report is usually the most valuable
anyway).
This number might have to be adjusted if you are not using serial
console or similar to capture the kernel log. If you are using the
"dmesg" command to save the log, then getting a lot of kmemcheck
warnings might overflow the kernel log itself, and the earlier reports
will get lost in that way instead. Try setting this to 10 or so on
such a setup.
- ``CONFIG_KMEMCHECK_SHADOW_COPY_SHIFT``
Select the number of shadow bytes to save along with each entry of the
error-report queue. These bytes indicate what parts of an allocation
are initialized, uninitialized, etc. and will be displayed when an
error is detected to help the debugging of a particular problem.
The number entered here is actually the logarithm of the number of
bytes that will be saved. So if you pick for example 5 here, kmemcheck
will save 2^5 = 32 bytes.
The default value should be fine for debugging most problems. It also
fits nicely within 80 columns.
- ``CONFIG_KMEMCHECK_PARTIAL_OK``
This option (when enabled) works around certain GCC optimizations that
produce 32-bit reads from 16-bit variables where the upper 16 bits are
thrown away afterwards.
The default value (enabled) is recommended. This may of course hide
some real errors, but disabling it would probably produce a lot of
false positives.
- ``CONFIG_KMEMCHECK_BITOPS_OK``
This option silences warnings that would be generated for bit-field
accesses where not all the bits are initialized at the same time. This
may also hide some real bugs.
This option is probably obsolete, or it should be replaced with
the kmemcheck-/bitfield-annotations for the code in question. The
default value is therefore fine.
Now compile the kernel as usual.
How to use
----------
Booting
~~~~~~~
First some information about the command-line options. There is only one
option specific to kmemcheck, and this is called "kmemcheck". It can be used
to override the default mode as chosen by the ``CONFIG_KMEMCHECK_*_BY_DEFAULT``
option. Its possible settings are:
- ``kmemcheck=0`` (disabled)
- ``kmemcheck=1`` (enabled)
- ``kmemcheck=2`` (one-shot mode)
If SLUB debugging has been enabled in the kernel, it may take precedence over
kmemcheck in such a way that the slab caches which are under SLUB debugging
will not be tracked by kmemcheck. In order to ensure that this doesn't happen
(even though it shouldn't by default), use SLUB's boot option ``slub_debug``,
like this: ``slub_debug=-``
In fact, this option may also be used for fine-grained control over SLUB vs.
kmemcheck. For example, if the command line includes
``kmemcheck=1 slub_debug=,dentry``, then SLUB debugging will be used only
for the "dentry" slab cache, and with kmemcheck tracking all the other
caches. This is advanced usage, however, and is not generally recommended.
Run-time enable/disable
~~~~~~~~~~~~~~~~~~~~~~~
When the kernel has booted, it is possible to enable or disable kmemcheck at
run-time. WARNING: This feature is still experimental and may cause false
positive warnings to appear. Therefore, try not to use this. If you find that
it doesn't work properly (e.g. you see an unreasonable amount of warnings), I
will be happy to take bug reports.
Use the file ``/proc/sys/kernel/kmemcheck`` for this purpose, e.g.::
$ echo 0 > /proc/sys/kernel/kmemcheck # disables kmemcheck
The numbers are the same as for the ``kmemcheck=`` command-line option.
Debugging
~~~~~~~~~
A typical report will look something like this::
WARNING: kmemcheck: Caught 32-bit read from uninitialized memory (ffff88003e4a2024)
80000000000000000000000000000000000000000088ffff0000000000000000
i i i i u u u u i i i i i i i i u u u u u u u u u u u u u u u u
^
Pid: 1856, comm: ntpdate Not tainted 2.6.29-rc5 #264 945P-A
RIP: 0010:[<ffffffff8104ede8>] [<ffffffff8104ede8>] __dequeue_signal+0xc8/0x190
RSP: 0018:ffff88003cdf7d98 EFLAGS: 00210002
RAX: 0000000000000030 RBX: ffff88003d4ea968 RCX: 0000000000000009
RDX: ffff88003e5d6018 RSI: ffff88003e5d6024 RDI: ffff88003cdf7e84
RBP: ffff88003cdf7db8 R08: ffff88003e5d6000 R09: 0000000000000000
R10: 0000000000000080 R11: 0000000000000000 R12: 000000000000000e
R13: ffff88003cdf7e78 R14: ffff88003d530710 R15: ffff88003d5a98c8
FS: 0000000000000000(0000) GS:ffff880001982000(0063) knlGS:00000
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: ffff88003f806ea0 CR3: 000000003c036000 CR4: 00000000000006a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000400
[<ffffffff8104f04e>] dequeue_signal+0x8e/0x170
[<ffffffff81050bd8>] get_signal_to_deliver+0x98/0x390
[<ffffffff8100b87d>] do_notify_resume+0xad/0x7d0
[<ffffffff8100c7b5>] int_signal+0x12/0x17
[<ffffffffffffffff>] 0xffffffffffffffff
The single most valuable information in this report is the RIP (or EIP on 32-
bit) value. This will help us pinpoint exactly which instruction that caused
the warning.
If your kernel was compiled with ``CONFIG_DEBUG_INFO=y``, then all we have to do
is give this address to the addr2line program, like this::
$ addr2line -e vmlinux -i ffffffff8104ede8
arch/x86/include/asm/string_64.h:12
include/asm-generic/siginfo.h:287
kernel/signal.c:380
kernel/signal.c:410
The "``-e vmlinux``" tells addr2line which file to look in. **IMPORTANT:**
This must be the vmlinux of the kernel that produced the warning in the
first place! If not, the line number information will almost certainly be
wrong.
The "``-i``" tells addr2line to also print the line numbers of inlined
functions. In this case, the flag was very important, because otherwise,
it would only have printed the first line, which is just a call to
``memcpy()``, which could be called from a thousand places in the kernel, and
is therefore not very useful. These inlined functions would not show up in
the stack trace above, simply because the kernel doesn't load the extra
debugging information. This technique can of course be used with ordinary
kernel oopses as well.
In this case, it's the caller of ``memcpy()`` that is interesting, and it can be
found in ``include/asm-generic/siginfo.h``, line 287::
281 static inline void copy_siginfo(struct siginfo *to, struct siginfo *from)
282 {
283 if (from->si_code < 0)
284 memcpy(to, from, sizeof(*to));
285 else
286 /* _sigchld is currently the largest know union member */
287 memcpy(to, from, __ARCH_SI_PREAMBLE_SIZE + sizeof(from->_sifields._sigchld));
288 }
Since this was a read (kmemcheck usually warns about reads only, though it can
warn about writes to unallocated or freed memory as well), it was probably the
"from" argument which contained some uninitialized bytes. Following the chain
of calls, we move upwards to see where "from" was allocated or initialized,
``kernel/signal.c``, line 380::
359 static void collect_signal(int sig, struct sigpending *list, siginfo_t *info)
360 {
...
367 list_for_each_entry(q, &list->list, list) {
368 if (q->info.si_signo == sig) {
369 if (first)
370 goto still_pending;
371 first = q;
...
377 if (first) {
378 still_pending:
379 list_del_init(&first->list);
380 copy_siginfo(info, &first->info);
381 __sigqueue_free(first);
...
392 }
393 }
Here, it is ``&first->info`` that is being passed on to ``copy_siginfo()``. The
variable ``first`` was found on a list -- passed in as the second argument to
``collect_signal()``. We continue our journey through the stack, to figure out
where the item on "list" was allocated or initialized. We move to line 410::
395 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
396 siginfo_t *info)
397 {
...
410 collect_signal(sig, pending, info);
...
414 }
Now we need to follow the ``pending`` pointer, since that is being passed on to
``collect_signal()`` as ``list``. At this point, we've run out of lines from the
"addr2line" output. Not to worry, we just paste the next addresses from the
kmemcheck stack dump, i.e.::
[<ffffffff8104f04e>] dequeue_signal+0x8e/0x170
[<ffffffff81050bd8>] get_signal_to_deliver+0x98/0x390
[<ffffffff8100b87d>] do_notify_resume+0xad/0x7d0
[<ffffffff8100c7b5>] int_signal+0x12/0x17
$ addr2line -e vmlinux -i ffffffff8104f04e ffffffff81050bd8 \
ffffffff8100b87d ffffffff8100c7b5
kernel/signal.c:446
kernel/signal.c:1806
arch/x86/kernel/signal.c:805
arch/x86/kernel/signal.c:871
arch/x86/kernel/entry_64.S:694
Remember that since these addresses were found on the stack and not as the
RIP value, they actually point to the _next_ instruction (they are return
addresses). This becomes obvious when we look at the code for line 446::
422 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
423 {
...
431 signr = __dequeue_signal(&tsk->signal->shared_pending,
432 mask, info);
433 /*
434 * itimer signal ?
435 *
436 * itimers are process shared and we restart periodic
437 * itimers in the signal delivery path to prevent DoS
438 * attacks in the high resolution timer case. This is
439 * compliant with the old way of self restarting
440 * itimers, as the SIGALRM is a legacy signal and only
441 * queued once. Changing the restart behaviour to
442 * restart the timer in the signal dequeue path is
443 * reducing the timer noise on heavy loaded !highres
444 * systems too.
445 */
446 if (unlikely(signr == SIGALRM)) {
...
489 }
So instead of looking at 446, we should be looking at 431, which is the line
that executes just before 446. Here we see that what we are looking for is
``&tsk->signal->shared_pending``.
Our next task is now to figure out which function that puts items on this
``shared_pending`` list. A crude, but efficient tool, is ``git grep``::
$ git grep -n 'shared_pending' kernel/
...
kernel/signal.c:828: pending = group ? &t->signal->shared_pending : &t->pending;
kernel/signal.c:1339: pending = group ? &t->signal->shared_pending : &t->pending;
...
There were more results, but none of them were related to list operations,
and these were the only assignments. We inspect the line numbers more closely
and find that this is indeed where items are being added to the list::
816 static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
817 int group)
818 {
...
828 pending = group ? &t->signal->shared_pending : &t->pending;
...
851 q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN &&
852 (is_si_special(info) ||
853 info->si_code >= 0)));
854 if (q) {
855 list_add_tail(&q->list, &pending->list);
...
890 }
and::
1309 int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
1310 {
....
1339 pending = group ? &t->signal->shared_pending : &t->pending;
1340 list_add_tail(&q->list, &pending->list);
....
1347 }
In the first case, the list element we are looking for, ``q``, is being
returned from the function ``__sigqueue_alloc()``, which looks like an
allocation function. Let's take a look at it::
187 static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
188 int override_rlimit)
189 {
190 struct sigqueue *q = NULL;
191 struct user_struct *user;
192
193 /*
194 * We won't get problems with the target's UID changing under us
195 * because changing it requires RCU be used, and if t != current, the
196 * caller must be holding the RCU readlock (by way of a spinlock) and
197 * we use RCU protection here
198 */
199 user = get_uid(__task_cred(t)->user);
200 atomic_inc(&user->sigpending);
201 if (override_rlimit ||
202 atomic_read(&user->sigpending) <=
203 t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur)
204 q = kmem_cache_alloc(sigqueue_cachep, flags);
205 if (unlikely(q == NULL)) {
206 atomic_dec(&user->sigpending);
207 free_uid(user);
208 } else {
209 INIT_LIST_HEAD(&q->list);
210 q->flags = 0;
211 q->user = user;
212 }
213
214 return q;
215 }
We see that this function initializes ``q->list``, ``q->flags``, and
``q->user``. It seems that now is the time to look at the definition of
``struct sigqueue``, e.g.::
14 struct sigqueue {
15 struct list_head list;
16 int flags;
17 siginfo_t info;
18 struct user_struct *user;
19 };
And, you might remember, it was a ``memcpy()`` on ``&first->info`` that
caused the warning, so this makes perfect sense. It also seems reasonable
to assume that it is the caller of ``__sigqueue_alloc()`` that has the
responsibility of filling out (initializing) this member.
But just which fields of the struct were uninitialized? Let's look at
kmemcheck's report again::
WARNING: kmemcheck: Caught 32-bit read from uninitialized memory (ffff88003e4a2024)
80000000000000000000000000000000000000000088ffff0000000000000000
i i i i u u u u i i i i i i i i u u u u u u u u u u u u u u u u
^
These first two lines are the memory dump of the memory object itself, and
the shadow bytemap, respectively. The memory object itself is in this case
``&first->info``. Just beware that the start of this dump is NOT the start
of the object itself! The position of the caret (^) corresponds with the
address of the read (ffff88003e4a2024).
The shadow bytemap dump legend is as follows:
- i: initialized
- u: uninitialized
- a: unallocated (memory has been allocated by the slab layer, but has not
yet been handed off to anybody)
- f: freed (memory has been allocated by the slab layer, but has been freed
by the previous owner)
In order to figure out where (relative to the start of the object) the
uninitialized memory was located, we have to look at the disassembly. For
that, we'll need the RIP address again::
RIP: 0010:[<ffffffff8104ede8>] [<ffffffff8104ede8>] __dequeue_signal+0xc8/0x190
$ objdump -d --no-show-raw-insn vmlinux | grep -C 8 ffffffff8104ede8:
ffffffff8104edc8: mov %r8,0x8(%r8)
ffffffff8104edcc: test %r10d,%r10d
ffffffff8104edcf: js ffffffff8104ee88 <__dequeue_signal+0x168>
ffffffff8104edd5: mov %rax,%rdx
ffffffff8104edd8: mov $0xc,%ecx
ffffffff8104eddd: mov %r13,%rdi
ffffffff8104ede0: mov $0x30,%eax
ffffffff8104ede5: mov %rdx,%rsi
ffffffff8104ede8: rep movsl %ds:(%rsi),%es:(%rdi)
ffffffff8104edea: test $0x2,%al
ffffffff8104edec: je ffffffff8104edf0 <__dequeue_signal+0xd0>
ffffffff8104edee: movsw %ds:(%rsi),%es:(%rdi)
ffffffff8104edf0: test $0x1,%al
ffffffff8104edf2: je ffffffff8104edf5 <__dequeue_signal+0xd5>
ffffffff8104edf4: movsb %ds:(%rsi),%es:(%rdi)
ffffffff8104edf5: mov %r8,%rdi
ffffffff8104edf8: callq ffffffff8104de60 <__sigqueue_free>
As expected, it's the "``rep movsl``" instruction from the ``memcpy()``
that causes the warning. We know about ``REP MOVSL`` that it uses the register
``RCX`` to count the number of remaining iterations. By taking a look at the
register dump again (from the kmemcheck report), we can figure out how many
bytes were left to copy::
RAX: 0000000000000030 RBX: ffff88003d4ea968 RCX: 0000000000000009
By looking at the disassembly, we also see that ``%ecx`` is being loaded
with the value ``$0xc`` just before (ffffffff8104edd8), so we are very
lucky. Keep in mind that this is the number of iterations, not bytes. And
since this is a "long" operation, we need to multiply by 4 to get the
number of bytes. So this means that the uninitialized value was encountered
at 4 * (0xc - 0x9) = 12 bytes from the start of the object.
We can now try to figure out which field of the "``struct siginfo``" that
was not initialized. This is the beginning of the struct::
40 typedef struct siginfo {
41 int si_signo;
42 int si_errno;
43 int si_code;
44
45 union {
..
92 } _sifields;
93 } siginfo_t;
On 64-bit, the int is 4 bytes long, so it must the union member that has
not been initialized. We can verify this using gdb::
$ gdb vmlinux
...
(gdb) p &((struct siginfo *) 0)->_sifields
$1 = (union {...} *) 0x10
Actually, it seems that the union member is located at offset 0x10 -- which
means that gcc has inserted 4 bytes of padding between the members ``si_code``
and ``_sifields``. We can now get a fuller picture of the memory dump::
_----------------------------=> si_code
/ _--------------------=> (padding)
| / _------------=> _sifields(._kill._pid)
| | / _----=> _sifields(._kill._uid)
| | | /
-------|-------|-------|-------|
80000000000000000000000000000000000000000088ffff0000000000000000
i i i i u u u u i i i i i i i i u u u u u u u u u u u u u u u u
This allows us to realize another important fact: ``si_code`` contains the
value 0x80. Remember that x86 is little endian, so the first 4 bytes
"80000000" are really the number 0x00000080. With a bit of research, we
find that this is actually the constant ``SI_KERNEL`` defined in
``include/asm-generic/siginfo.h``::
144 #define SI_KERNEL 0x80 /* sent by the kernel from somewhere */
This macro is used in exactly one place in the x86 kernel: In ``send_signal()``
in ``kernel/signal.c``::
816 static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
817 int group)
818 {
...
828 pending = group ? &t->signal->shared_pending : &t->pending;
...
851 q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN &&
852 (is_si_special(info) ||
853 info->si_code >= 0)));
854 if (q) {
855 list_add_tail(&q->list, &pending->list);
856 switch ((unsigned long) info) {
...
865 case (unsigned long) SEND_SIG_PRIV:
866 q->info.si_signo = sig;
867 q->info.si_errno = 0;
868 q->info.si_code = SI_KERNEL;
869 q->info.si_pid = 0;
870 q->info.si_uid = 0;
871 break;
...
890 }
Not only does this match with the ``.si_code`` member, it also matches the place
we found earlier when looking for where siginfo_t objects are enqueued on the
``shared_pending`` list.
So to sum up: It seems that it is the padding introduced by the compiler
between two struct fields that is uninitialized, and this gets reported when
we do a ``memcpy()`` on the struct. This means that we have identified a false
positive warning.
Normally, kmemcheck will not report uninitialized accesses in ``memcpy()`` calls
when both the source and destination addresses are tracked. (Instead, we copy
the shadow bytemap as well). In this case, the destination address clearly
was not tracked. We can dig a little deeper into the stack trace from above::
arch/x86/kernel/signal.c:805
arch/x86/kernel/signal.c:871
arch/x86/kernel/entry_64.S:694
And we clearly see that the destination siginfo object is located on the
stack::
782 static void do_signal(struct pt_regs *regs)
783 {
784 struct k_sigaction ka;
785 siginfo_t info;
...
804 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
...
854 }
And this ``&info`` is what eventually gets passed to ``copy_siginfo()`` as the
destination argument.
Now, even though we didn't find an actual error here, the example is still a
good one, because it shows how one would go about to find out what the report
was all about.
Annotating false positives
~~~~~~~~~~~~~~~~~~~~~~~~~~
There are a few different ways to make annotations in the source code that
will keep kmemcheck from checking and reporting certain allocations. Here
they are:
- ``__GFP_NOTRACK_FALSE_POSITIVE``
This flag can be passed to ``kmalloc()`` or ``kmem_cache_alloc()``
(therefore also to other functions that end up calling one of
these) to indicate that the allocation should not be tracked
because it would lead to a false positive report. This is a "big
hammer" way of silencing kmemcheck; after all, even if the false
positive pertains to particular field in a struct, for example, we
will now lose the ability to find (real) errors in other parts of
the same struct.
Example::
/* No warnings will ever trigger on accessing any part of x */
x = kmalloc(sizeof *x, GFP_KERNEL | __GFP_NOTRACK_FALSE_POSITIVE);
- ``kmemcheck_bitfield_begin(name)``/``kmemcheck_bitfield_end(name)`` and
``kmemcheck_annotate_bitfield(ptr, name)``
The first two of these three macros can be used inside struct
definitions to signal, respectively, the beginning and end of a
bitfield. Additionally, this will assign the bitfield a name, which
is given as an argument to the macros.
Having used these markers, one can later use
kmemcheck_annotate_bitfield() at the point of allocation, to indicate
which parts of the allocation is part of a bitfield.
Example::
struct foo {
int x;
kmemcheck_bitfield_begin(flags);
int flag_a:1;
int flag_b:1;
kmemcheck_bitfield_end(flags);
int y;
};
struct foo *x = kmalloc(sizeof *x);
/* No warnings will trigger on accessing the bitfield of x */
kmemcheck_annotate_bitfield(x, flags);
Note that ``kmemcheck_annotate_bitfield()`` can be used even before the
return value of ``kmalloc()`` is checked -- in other words, passing NULL
as the first argument is legal (and will do nothing).
Reporting errors
----------------
As we have seen, kmemcheck will produce false positive reports. Therefore, it
is not very wise to blindly post kmemcheck warnings to mailing lists and
maintainers. Instead, I encourage maintainers and developers to find errors
in their own code. If you get a warning, you can try to work around it, try
to figure out if it's a real error or not, or simply ignore it. Most
developers know their own code and will quickly and efficiently determine the
root cause of a kmemcheck report. This is therefore also the most efficient
way to work with kmemcheck.
That said, we (the kmemcheck maintainers) will always be on the lookout for
false positives that we can annotate and silence. So whatever you find,
please drop us a note privately! Kernel configs and steps to reproduce (if
available) are of course a great help too.
Happy hacking!
Technical description
---------------------
kmemcheck works by marking memory pages non-present. This means that whenever
somebody attempts to access the page, a page fault is generated. The page
fault handler notices that the page was in fact only hidden, and so it calls
on the kmemcheck code to make further investigations.
When the investigations are completed, kmemcheck "shows" the page by marking
it present (as it would be under normal circumstances). This way, the
interrupted code can continue as usual.
But after the instruction has been executed, we should hide the page again, so
that we can catch the next access too! Now kmemcheck makes use of a debugging
feature of the processor, namely single-stepping. When the processor has
finished the one instruction that generated the memory access, a debug
exception is raised. From here, we simply hide the page again and continue
execution, this time with the single-stepping feature turned off.
kmemcheck requires some assistance from the memory allocator in order to work.
The memory allocator needs to
1. Tell kmemcheck about newly allocated pages and pages that are about to
be freed. This allows kmemcheck to set up and tear down the shadow memory
for the pages in question. The shadow memory stores the status of each
byte in the allocation proper, e.g. whether it is initialized or
uninitialized.
2. Tell kmemcheck which parts of memory should be marked uninitialized.
There are actually a few more states, such as "not yet allocated" and
"recently freed".
If a slab cache is set up using the SLAB_NOTRACK flag, it will never return
memory that can take page faults because of kmemcheck.
If a slab cache is NOT set up using the SLAB_NOTRACK flag, callers can still
request memory with the __GFP_NOTRACK or __GFP_NOTRACK_FALSE_POSITIVE flags.
This does not prevent the page faults from occurring, however, but marks the
object in question as being initialized so that no warnings will ever be
produced for this object.
Currently, the SLAB and SLUB allocators are supported by kmemcheck.

83
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@ -1,15 +1,12 @@
Kernel Memory Leak Detector
===========================
Introduction
------------
Kmemleak provides a way of detecting possible kernel memory leaks in a
way similar to a tracing garbage collector
(https://en.wikipedia.org/wiki/Garbage_collection_%28computer_science%29#Tracing_garbage_collectors),
with the difference that the orphan objects are not freed but only
reported via /sys/kernel/debug/kmemleak. A similar method is used by the
Valgrind tool (memcheck --leak-check) to detect the memory leaks in
Valgrind tool (``memcheck --leak-check``) to detect the memory leaks in
user-space applications.
Kmemleak is supported on x86, arm, powerpc, sparc, sh, microblaze, ppc, mips, s390, metag and tile.
@ -19,20 +16,20 @@ Usage
CONFIG_DEBUG_KMEMLEAK in "Kernel hacking" has to be enabled. A kernel
thread scans the memory every 10 minutes (by default) and prints the
number of new unreferenced objects found. To display the details of all
the possible memory leaks:
the possible memory leaks::
# mount -t debugfs nodev /sys/kernel/debug/
# cat /sys/kernel/debug/kmemleak
To trigger an intermediate memory scan:
To trigger an intermediate memory scan::
# echo scan > /sys/kernel/debug/kmemleak
To clear the list of all current possible memory leaks:
To clear the list of all current possible memory leaks::
# echo clear > /sys/kernel/debug/kmemleak
New leaks will then come up upon reading /sys/kernel/debug/kmemleak
New leaks will then come up upon reading ``/sys/kernel/debug/kmemleak``
again.
Note that the orphan objects are listed in the order they were allocated
@ -40,22 +37,31 @@ and one object at the beginning of the list may cause other subsequent
objects to be reported as orphan.
Memory scanning parameters can be modified at run-time by writing to the
/sys/kernel/debug/kmemleak file. The following parameters are supported:
``/sys/kernel/debug/kmemleak`` file. The following parameters are supported:
off - disable kmemleak (irreversible)
stack=on - enable the task stacks scanning (default)
stack=off - disable the tasks stacks scanning
scan=on - start the automatic memory scanning thread (default)
scan=off - stop the automatic memory scanning thread
scan=<secs> - set the automatic memory scanning period in seconds
- off
disable kmemleak (irreversible)
- stack=on
enable the task stacks scanning (default)
- stack=off
disable the tasks stacks scanning
- scan=on
start the automatic memory scanning thread (default)
- scan=off
stop the automatic memory scanning thread
- scan=<secs>
set the automatic memory scanning period in seconds
(default 600, 0 to stop the automatic scanning)
scan - trigger a memory scan
clear - clear list of current memory leak suspects, done by
- scan
trigger a memory scan
- clear
clear list of current memory leak suspects, done by
marking all current reported unreferenced objects grey,
or free all kmemleak objects if kmemleak has been disabled.
dump=<addr> - dump information about the object found at <addr>
- dump=<addr>
dump information about the object found at <addr>
Kmemleak can also be disabled at boot-time by passing "kmemleak=off" on
Kmemleak can also be disabled at boot-time by passing ``kmemleak=off`` on
the kernel command line.
Memory may be allocated or freed before kmemleak is initialised and
@ -63,13 +69,14 @@ these actions are stored in an early log buffer. The size of this buffer
is configured via the CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE option.
If CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF are enabled, the kmemleak is
disabled by default. Passing "kmemleak=on" on the kernel command
disabled by default. Passing ``kmemleak=on`` on the kernel command
line enables the function.
Basic Algorithm
---------------
The memory allocations via kmalloc, vmalloc, kmem_cache_alloc and
The memory allocations via :c:func:`kmalloc`, :c:func:`vmalloc`,
:c:func:`kmem_cache_alloc` and
friends are traced and the pointers, together with additional
information like size and stack trace, are stored in a rbtree.
The corresponding freeing function calls are tracked and the pointers
@ -113,13 +120,13 @@ when doing development. To work around these situations you can use the
you can find new unreferenced objects; this should help with testing
specific sections of code.
To test a critical section on demand with a clean kmemleak do:
To test a critical section on demand with a clean kmemleak do::
# echo clear > /sys/kernel/debug/kmemleak
... test your kernel or modules ...
# echo scan > /sys/kernel/debug/kmemleak
Then as usual to get your report with:
Then as usual to get your report with::
# cat /sys/kernel/debug/kmemleak
@ -131,7 +138,7 @@ disabled by the user or due to an fatal error, internal kmemleak objects
won't be freed when kmemleak is disabled, and those objects may occupy
a large part of physical memory.
In this situation, you may reclaim memory with:
In this situation, you may reclaim memory with::
# echo clear > /sys/kernel/debug/kmemleak
@ -140,20 +147,20 @@ Kmemleak API
See the include/linux/kmemleak.h header for the functions prototype.
kmemleak_init - initialize kmemleak
kmemleak_alloc - notify of a memory block allocation
kmemleak_alloc_percpu - notify of a percpu memory block allocation
kmemleak_free - notify of a memory block freeing
kmemleak_free_part - notify of a partial memory block freeing
kmemleak_free_percpu - notify of a percpu memory block freeing
kmemleak_update_trace - update object allocation stack trace
kmemleak_not_leak - mark an object as not a leak
kmemleak_ignore - do not scan or report an object as leak
kmemleak_scan_area - add scan areas inside a memory block
kmemleak_no_scan - do not scan a memory block
kmemleak_erase - erase an old value in a pointer variable
kmemleak_alloc_recursive - as kmemleak_alloc but checks the recursiveness
kmemleak_free_recursive - as kmemleak_free but checks the recursiveness
- ``kmemleak_init`` - initialize kmemleak
- ``kmemleak_alloc`` - notify of a memory block allocation
- ``kmemleak_alloc_percpu`` - notify of a percpu memory block allocation
- ``kmemleak_free`` - notify of a memory block freeing
- ``kmemleak_free_part`` - notify of a partial memory block freeing
- ``kmemleak_free_percpu`` - notify of a percpu memory block freeing
- ``kmemleak_update_trace`` - update object allocation stack trace
- ``kmemleak_not_leak`` - mark an object as not a leak
- ``kmemleak_ignore`` - do not scan or report an object as leak
- ``kmemleak_scan_area`` - add scan areas inside a memory block
- ``kmemleak_no_scan`` - do not scan a memory block
- ``kmemleak_erase`` - erase an old value in a pointer variable
- ``kmemleak_alloc_recursive`` - as kmemleak_alloc but checks the recursiveness
- ``kmemleak_free_recursive`` - as kmemleak_free but checks the recursiveness
Dealing with false positives/negatives
--------------------------------------

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@ -1,11 +1,20 @@
Copyright 2004 Linus Torvalds
Copyright 2004 Pavel Machek <pavel@ucw.cz>
Copyright 2006 Bob Copeland <me@bobcopeland.com>
.. Copyright 2004 Linus Torvalds
.. Copyright 2004 Pavel Machek <pavel@ucw.cz>
.. Copyright 2006 Bob Copeland <me@bobcopeland.com>
Sparse
======
Sparse is a semantic checker for C programs; it can be used to find a
number of potential problems with kernel code. See
https://lwn.net/Articles/689907/ for an overview of sparse; this document
contains some kernel-specific sparse information.
Using sparse for typechecking
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-----------------------------
"__bitwise" is a type attribute, so you have to do something like this:
"__bitwise" is a type attribute, so you have to do something like this::
typedef int __bitwise pm_request_t;
@ -20,13 +29,13 @@ but in this case we really _do_ want to force the conversion). And because
the enum values are all the same type, now "enum pm_request" will be that
type too.
And with gcc, all the __bitwise/__force stuff goes away, and it all ends
up looking just like integers to gcc.
And with gcc, all the "__bitwise"/"__force stuff" goes away, and it all
ends up looking just like integers to gcc.
Quite frankly, you don't need the enum there. The above all really just
boils down to one special "int __bitwise" type.
So the simpler way is to just do
So the simpler way is to just do::
typedef int __bitwise pm_request_t;
@ -50,7 +59,7 @@ __bitwise - noisy stuff; in particular, __le*/__be* are that. We really
don't want to drown in noise unless we'd explicitly asked for it.
Using sparse for lock checking
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
------------------------------
The following macros are undefined for gcc and defined during a sparse
run to use the "context" tracking feature of sparse, applied to
@ -69,22 +78,22 @@ annotation is needed. The tree annotations above are for cases where
sparse would otherwise report a context imbalance.
Getting sparse
~~~~~~~~~~~~~~
--------------
You can get latest released versions from the Sparse homepage at
https://sparse.wiki.kernel.org/index.php/Main_Page
Alternatively, you can get snapshots of the latest development version
of sparse using git to clone..
of sparse using git to clone::
git://git.kernel.org/pub/scm/devel/sparse/sparse.git
DaveJ has hourly generated tarballs of the git tree available at..
DaveJ has hourly generated tarballs of the git tree available at::
http://www.codemonkey.org.uk/projects/git-snapshots/sparse/
Once you have it, just do
Once you have it, just do::
make
make install
@ -92,7 +101,7 @@ Once you have it, just do
as a regular user, and it will install sparse in your ~/bin directory.
Using sparse
~~~~~~~~~~~~
------------
Do a kernel make with "make C=1" to run sparse on all the C files that get
recompiled, or use "make C=2" to run sparse on the files whether they need to
@ -101,7 +110,7 @@ have already built it.
The optional make variable CF can be used to pass arguments to sparse. The
build system passes -Wbitwise to sparse automatically. To perform endianness
checks, you may define __CHECK_ENDIAN__:
checks, you may define __CHECK_ENDIAN__::
make C=2 CF="-D__CHECK_ENDIAN__"

25
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@ -0,0 +1,25 @@
================================
Development tools for the kernel
================================
This document is a collection of documents about development tools that can
be used to work on the kernel. For now, the documents have been pulled
together without any significant effot to integrate them into a coherent
whole; patches welcome!
.. class:: toc-title
Table of contents
.. toctree::
:maxdepth: 2
coccinelle
sparse
kcov
gcov
kasan
ubsan
kmemleak
kmemcheck
gdb-kernel-debugging

34
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@ -1,7 +1,5 @@
Undefined Behavior Sanitizer - UBSAN
Overview
--------
The Undefined Behavior Sanitizer - UBSAN
========================================
UBSAN is a runtime undefined behaviour checker.
@ -10,11 +8,13 @@ Compiler inserts code that perform certain kinds of checks before operations
that may cause UB. If check fails (i.e. UB detected) __ubsan_handle_*
function called to print error message.
GCC has that feature since 4.9.x [1] (see -fsanitize=undefined option and
its suboptions). GCC 5.x has more checkers implemented [2].
GCC has that feature since 4.9.x [1_] (see ``-fsanitize=undefined`` option and
its suboptions). GCC 5.x has more checkers implemented [2_].
Report example
---------------
--------------
::
================================================================================
UBSAN: Undefined behaviour in ../include/linux/bitops.h:110:33
@ -47,28 +47,32 @@ Report example
Usage
-----
To enable UBSAN configure kernel with:
To enable UBSAN configure kernel with::
CONFIG_UBSAN=y
and to check the entire kernel:
and to check the entire kernel::
CONFIG_UBSAN_SANITIZE_ALL=y
To enable instrumentation for specific files or directories, add a line
similar to the following to the respective kernel Makefile:
For a single file (e.g. main.o):
- For a single file (e.g. main.o)::
UBSAN_SANITIZE_main.o := y
For all files in one directory:
- For all files in one directory::
UBSAN_SANITIZE := y
To exclude files from being instrumented even if
CONFIG_UBSAN_SANITIZE_ALL=y, use:
``CONFIG_UBSAN_SANITIZE_ALL=y``, use::
UBSAN_SANITIZE_main.o := n
and:
and::
UBSAN_SANITIZE := n
Detection of unaligned accesses controlled through the separate option -
@ -80,5 +84,5 @@ reports.
References
----------
[1] - https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html
[2] - https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html
.. _1: https://gcc.gnu.org/onlinedocs/gcc-4.9.0/gcc/Debugging-Options.html
.. _2: https://gcc.gnu.org/onlinedocs/gcc/Debugging-Options.html

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@ -0,0 +1,65 @@
Atmel Image Sensor Controller (ISC)
----------------------------------------------
Required properties for ISC:
- compatible
Must be "atmel,sama5d2-isc".
- reg
Physical base address and length of the registers set for the device.
- interrupts
Should contain IRQ line for the ISC.
- clocks
List of clock specifiers, corresponding to entries in
the clock-names property;
Please refer to clock-bindings.txt.
- clock-names
Required elements: "hclock", "iscck", "gck".
- #clock-cells
Should be 0.
- clock-output-names
Should be "isc-mck".
- pinctrl-names, pinctrl-0
Please refer to pinctrl-bindings.txt.
ISC supports a single port node with parallel bus. It should contain one
'port' child node with child 'endpoint' node. Please refer to the bindings
defined in Documentation/devicetree/bindings/media/video-interfaces.txt.
Example:
isc: isc@f0008000 {
compatible = "atmel,sama5d2-isc";
reg = <0xf0008000 0x4000>;
interrupts = <46 IRQ_TYPE_LEVEL_HIGH 5>;
clocks = <&isc_clk>, <&iscck>, <&isc_gclk>;
clock-names = "hclock", "iscck", "gck";
#clock-cells = <0>;
clock-output-names = "isc-mck";
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_isc_base &pinctrl_isc_data_8bit &pinctrl_isc_data_9_10 &pinctrl_isc_data_11_12>;
port {
isc_0: endpoint {
remote-endpoint = <&ov7740_0>;
hsync-active = <1>;
vsync-active = <0>;
pclk-sample = <1>;
};
};
};
i2c1: i2c@fc028000 {
ov7740: camera@21 {
compatible = "ovti,ov7740";
reg = <0x21>;
clocks = <&isc>;
clock-names = "xvclk";
assigned-clocks = <&isc>;
assigned-clock-rates = <24000000>;
port {
ov7740_0: endpoint {
remote-endpoint = <&isc_0>;
};
};
};
};

7
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@ -16,9 +16,10 @@ Required properties:
- clocks : list of clock specifiers, corresponding to entries in
clock-names property;
- clock-names : must contain "ppmuispx", "ppmuispx", "lite0", "lite1"
"mpll", "sysreg", "isp", "drc", "fd", "mcuisp", "uart",
"ispdiv0", "ispdiv1", "mcuispdiv0", "mcuispdiv1", "aclk200",
"div_aclk200", "aclk400mcuisp", "div_aclk400mcuisp" entries,
"mpll", "sysreg", "isp", "drc", "fd", "mcuisp", "gicisp",
"pwm_isp", "mcuctl_isp", "uart", "ispdiv0", "ispdiv1",
"mcuispdiv0", "mcuispdiv1", "aclk200", "div_aclk200",
"aclk400mcuisp", "div_aclk400mcuisp" entries,
matching entries in the clocks property.
pmu subnode
-----------

19
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@ -0,0 +1,19 @@
* Analog Devices AD5820 autofocus coil
Required Properties:
- compatible: Must contain "adi,ad5820"
- reg: I2C slave address
- VANA-supply: supply of voltage for VANA pin
Example:
ad5820: coil@c {
compatible = "adi,ad5820";
reg = <0x0c>;
VANA-supply = <&vaux4>;
};

5
Documentation/devicetree/bindings/media/i2c/adv7180.txt
View File

@ -15,6 +15,11 @@ Required Properties :
"adi,adv7282"
"adi,adv7282-m"
Optional Properties :
- powerdown-gpios: reference to the GPIO connected to the powerdown pin,
if any.
Example:
i2c0@1c22000 {

9
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@ -7,12 +7,14 @@ conversion of AXI transactions in order to reduce the memory bandwidth.
There are three types of FCP: FCP for Codec (FCPC), FCP for VSP (FCPV) and FCP
for FDP (FCPF). Their configuration and behaviour depend on the module they
are paired with. These DT bindings currently support the FCPV only.
are paired with. These DT bindings currently support the FCPV and FCPF.
- compatible: Must be one or more of the following
- "renesas,r8a7795-fcpv" for R8A7795 (R-Car H3) compatible 'FCP for VSP'
- "renesas,r8a7795-fcpf" for R8A7795 (R-Car H3) compatible 'FCP for FDP'
- "renesas,fcpv" for generic compatible 'FCP for VSP'
- "renesas,fcpf" for generic compatible 'FCP for FDP'
When compatible with the generic version, nodes must list the
SoC-specific version corresponding to the platform first, followed by the
@ -21,6 +23,10 @@ are paired with. These DT bindings currently support the FCPV only.
- reg: the register base and size for the device registers
- clocks: Reference to the functional clock
Optional properties:
- power-domains : power-domain property defined with a power domain specifier
to respective power domain.
Device node example
-------------------
@ -29,4 +35,5 @@ Device node example
compatible = "renesas,r8a7795-fcpv", "renesas,fcpv";
reg = <0 0xfea2f000 0 0x200>;
clocks = <&cpg CPG_MOD 602>;
power-domains = <&sysc R8A7795_PD_A3VP>;
};

24
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@ -0,0 +1,24 @@
st-hva: multi-format video encoder for STMicroelectronics SoC.
Required properties:
- compatible: should be "st,st-hva".
- reg: HVA physical address location and length, esram address location and
length.
- reg-names: names of the registers listed in registers property in the same
order.
- interrupts: HVA interrupt number.
- clocks: from common clock binding: handle hardware IP needed clocks, the
number of clocks may depend on the SoC type.
See ../clock/clock-bindings.txt for details.
- clock-names: names of the clocks listed in clocks property in the same order.
Example:
hva@8c85000{
compatible = "st,st-hva";
reg = <0x8c85000 0x400>, <0x6000000 0x40000>;
reg-names = "hva_registers", "hva_esram";
interrupts = <GIC_SPI 58 IRQ_TYPE_NONE>,
<GIC_SPI 59 IRQ_TYPE_NONE>;
clock-names = "clk_hva";
clocks = <&clk_s_c0_flexgen CLK_HVA>;
};

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@ -0,0 +1,25 @@
STMicroelectronics STIH4xx HDMI CEC driver
Required properties:
- compatible : value should be "st,stih-cec"
- reg : Physical base address of the IP registers and length of memory
mapped region.
- clocks : from common clock binding: handle to HDMI CEC clock
- interrupts : HDMI CEC interrupt number to the CPU.
- pinctrl-names: Contains only one value - "default"
- pinctrl-0: Specifies the pin control groups used for CEC hardware.
- resets: Reference to a reset controller
Example for STIH407:
sti-cec@094a087c {
compatible = "st,stih-cec";
reg = <0x94a087c 0x64>;
clocks = <&clk_sysin>;
clock-names = "cec-clk";
interrupts = <GIC_SPI 140 IRQ_TYPE_NONE>;
interrupt-names = "cec-irq";
pinctrl-names = "default";
pinctrl-0 = <&pinctrl_cec0_default>;
resets = <&softreset STIH407_LPM_SOFTRESET>;
};

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@ -0,0 +1,7 @@
# -*- coding: utf-8 mode: conf-colon -*-
#
# docutils configuration file
# http://docutils.sourceforge.net/docs/user/config.html
[general]
halt_level: severe

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@ -0,0 +1,120 @@
Driver Basics
=============
Driver Entry and Exit points
----------------------------
.. kernel-doc:: include/linux/init.h
:internal:
Atomic and pointer manipulation
-------------------------------
.. kernel-doc:: arch/x86/include/asm/atomic.h
:internal:
Delaying, scheduling, and timer routines
----------------------------------------
.. kernel-doc:: include/linux/sched.h
:internal:
.. kernel-doc:: kernel/sched/core.c
:export:
.. kernel-doc:: kernel/sched/cpupri.c
:internal:
.. kernel-doc:: kernel/sched/fair.c
:internal:
.. kernel-doc:: include/linux/completion.h
:internal:
.. kernel-doc:: kernel/time/timer.c
:export:
Wait queues and Wake events
---------------------------
.. kernel-doc:: include/linux/wait.h
:internal:
.. kernel-doc:: kernel/sched/wait.c
:export:
High-resolution timers
----------------------
.. kernel-doc:: include/linux/ktime.h
:internal:
.. kernel-doc:: include/linux/hrtimer.h
:internal:
.. kernel-doc:: kernel/time/hrtimer.c
:export:
Workqueues and Kevents
----------------------
.. kernel-doc:: include/linux/workqueue.h
:internal:
.. kernel-doc:: kernel/workqueue.c
:export:
Internal Functions
------------------
.. kernel-doc:: kernel/exit.c
:internal:
.. kernel-doc:: kernel/signal.c
:internal:
.. kernel-doc:: include/linux/kthread.h
:internal:
.. kernel-doc:: kernel/kthread.c
:export:
Kernel objects manipulation
---------------------------
.. kernel-doc:: lib/kobject.c
:export:
Kernel utility functions
------------------------
.. kernel-doc:: include/linux/kernel.h
:internal:
.. kernel-doc:: kernel/printk/printk.c
:export:
.. kernel-doc:: kernel/panic.c
:export:
.. kernel-doc:: kernel/sys.c
:export:
.. kernel-doc:: kernel/rcu/srcu.c
:export:
.. kernel-doc:: kernel/rcu/tree.c
:export:
.. kernel-doc:: kernel/rcu/tree_plugin.h
:export:
.. kernel-doc:: kernel/rcu/update.c
:export:
Device Resource Management
--------------------------
.. kernel-doc:: drivers/base/devres.c
:export:

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Frame Buffer Library
====================
The frame buffer drivers depend heavily on four data structures. These
structures are declared in include/linux/fb.h. They are fb_info,
fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs. The last
three can be made available to and from userland.
fb_info defines the current state of a particular video card. Inside
fb_info, there exists a fb_ops structure which is a collection of
needed functions to make fbdev and fbcon work. fb_info is only visible
to the kernel.
fb_var_screeninfo is used to describe the features of a video card
that are user defined. With fb_var_screeninfo, things such as depth
and the resolution may be defined.
The next structure is fb_fix_screeninfo. This defines the properties
of a card that are created when a mode is set and can't be changed
otherwise. A good example of this is the start of the frame buffer
memory. This "locks" the address of the frame buffer memory, so that it
cannot be changed or moved.
The last structure is fb_monospecs. In the old API, there was little
importance for fb_monospecs. This allowed for forbidden things such as
setting a mode of 800x600 on a fix frequency monitor. With the new API,
fb_monospecs prevents such things, and if used correctly, can prevent a
monitor from being cooked. fb_monospecs will not be useful until
kernels 2.5.x.
Frame Buffer Memory
-------------------
.. kernel-doc:: drivers/video/fbdev/core/fbmem.c
:export:
Frame Buffer Colormap
---------------------
.. kernel-doc:: drivers/video/fbdev/core/fbcmap.c
:export:
Frame Buffer Video Mode Database
--------------------------------
.. kernel-doc:: drivers/video/fbdev/core/modedb.c
:internal:
.. kernel-doc:: drivers/video/fbdev/core/modedb.c
:export:
Frame Buffer Macintosh Video Mode Database
------------------------------------------
.. kernel-doc:: drivers/video/fbdev/macmodes.c
:export:
Frame Buffer Fonts
------------------
Refer to the file lib/fonts/fonts.c for more information.

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High Speed Synchronous Serial Interface (HSI)
=============================================
Introduction
---------------
High Speed Syncronous Interface (HSI) is a fullduplex, low latency protocol,
that is optimized for die-level interconnect between an Application Processor
and a Baseband chipset. It has been specified by the MIPI alliance in 2003 and
implemented by multiple vendors since then.
The HSI interface supports full duplex communication over multiple channels
(typically 8) and is capable of reaching speeds up to 200 Mbit/s.
The serial protocol uses two signals, DATA and FLAG as combined data and clock
signals and an additional READY signal for flow control. An additional WAKE
signal can be used to wakeup the chips from standby modes. The signals are
commonly prefixed by AC for signals going from the application die to the
cellular die and CA for signals going the other way around.
::
+------------+ +---------------+
| Cellular | | Application |
| Die | | Die |
| | - - - - - - CAWAKE - - - - - - >| |
| T|------------ CADATA ------------>|R |
| X|------------ CAFLAG ------------>|X |
| |<----------- ACREADY ------------| |
| | | |
| | | |
| |< - - - - - ACWAKE - - - - - - -| |
| R|<----------- ACDATA -------------|T |
| X|<----------- ACFLAG -------------|X |
| |------------ CAREADY ----------->| |
| | | |
| | | |
+------------+ +---------------+
HSI Subsystem in Linux
-------------------------
In the Linux kernel the hsi subsystem is supposed to be used for HSI devices.
The hsi subsystem contains drivers for hsi controllers including support for
multi-port controllers and provides a generic API for using the HSI ports.
It also contains HSI client drivers, which make use of the generic API to
implement a protocol used on the HSI interface. These client drivers can
use an arbitrary number of channels.
hsi-char Device
------------------
Each port automatically registers a generic client driver called hsi_char,
which provides a charecter device for userspace representing the HSI port.
It can be used to communicate via HSI from userspace. Userspace may
configure the hsi_char device using the following ioctl commands:
HSC_RESET
flush the HSI port
HSC_SET_PM
enable or disable the client.
HSC_SEND_BREAK
send break
HSC_SET_RX
set RX configuration
HSC_GET_RX
get RX configuration
HSC_SET_TX
set TX configuration
HSC_GET_TX
get TX configuration
The kernel HSI API
------------------
.. kernel-doc:: include/linux/hsi/hsi.h
:internal:
.. kernel-doc:: drivers/hsi/hsi_core.c
:export:

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@ -0,0 +1,46 @@
I\ :sup:`2`\ C and SMBus Subsystem
==================================
I\ :sup:`2`\ C (or without fancy typography, "I2C") is an acronym for
the "Inter-IC" bus, a simple bus protocol which is widely used where low
data rate communications suffice. Since it's also a licensed trademark,
some vendors use another name (such as "Two-Wire Interface", TWI) for
the same bus. I2C only needs two signals (SCL for clock, SDA for data),
conserving board real estate and minimizing signal quality issues. Most
I2C devices use seven bit addresses, and bus speeds of up to 400 kHz;
there's a high speed extension (3.4 MHz) that's not yet found wide use.
I2C is a multi-master bus; open drain signaling is used to arbitrate
between masters, as well as to handshake and to synchronize clocks from
slower clients.
The Linux I2C programming interfaces support only the master side of bus
interactions, not the slave side. The programming interface is
structured around two kinds of driver, and two kinds of device. An I2C
"Adapter Driver" abstracts the controller hardware; it binds to a
physical device (perhaps a PCI device or platform_device) and exposes a
:c:type:`struct i2c_adapter <i2c_adapter>` representing each
I2C bus segment it manages. On each I2C bus segment will be I2C devices
represented by a :c:type:`struct i2c_client <i2c_client>`.
Those devices will be bound to a :c:type:`struct i2c_driver
<i2c_driver>`, which should follow the standard Linux driver
model. (At this writing, a legacy model is more widely used.) There are
functions to perform various I2C protocol operations; at this writing
all such functions are usable only from task context.
The System Management Bus (SMBus) is a sibling protocol. Most SMBus
systems are also I2C conformant. The electrical constraints are tighter
for SMBus, and it standardizes particular protocol messages and idioms.
Controllers that support I2C can also support most SMBus operations, but
SMBus controllers don't support all the protocol options that an I2C
controller will. There are functions to perform various SMBus protocol
operations, either using I2C primitives or by issuing SMBus commands to
i2c_adapter devices which don't support those I2C operations.
.. kernel-doc:: include/linux/i2c.h
:internal:
.. kernel-doc:: drivers/i2c/i2c-boardinfo.c
:functions: i2c_register_board_info
.. kernel-doc:: drivers/i2c/i2c-core.c
:export:

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@ -0,0 +1,26 @@
========================================
The Linux driver implementer's API guide
========================================
The kernel offers a wide variety of interfaces to support the development
of device drivers. This document is an only somewhat organized collection
of some of those interfaces — it will hopefully get better over time! The
available subsections can be seen below.
.. class:: toc-title
Table of contents
.. toctree::
:maxdepth: 2
basics
infrastructure
message-based
sound
frame-buffer
input
spi
i2c
hsi
miscellaneous

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@ -0,0 +1,169 @@
Device drivers infrastructure
=============================
The Basic Device Driver-Model Structures
----------------------------------------
.. kernel-doc:: include/linux/device.h
:internal:
Device Drivers Base
-------------------
.. kernel-doc:: drivers/base/init.c
:internal:
.. kernel-doc:: drivers/base/driver.c
:export:
.. kernel-doc:: drivers/base/core.c
:export:
.. kernel-doc:: drivers/base/syscore.c
:export:
.. kernel-doc:: drivers/base/class.c
:export:
.. kernel-doc:: drivers/base/node.c
:internal:
.. kernel-doc:: drivers/base/firmware_class.c
:export:
.. kernel-doc:: drivers/base/transport_class.c
:export:
.. kernel-doc:: drivers/base/dd.c
:export:
.. kernel-doc:: include/linux/platform_device.h
:internal:
.. kernel-doc:: drivers/base/platform.c
:export:
.. kernel-doc:: drivers/base/bus.c
:export:
Buffer Sharing and Synchronization
----------------------------------
The dma-buf subsystem provides the framework for sharing buffers for
hardware (DMA) access across multiple device drivers and subsystems, and
for synchronizing asynchronous hardware access.
This is used, for example, by drm "prime" multi-GPU support, but is of
course not limited to GPU use cases.
The three main components of this are: (1) dma-buf, representing a
sg_table and exposed to userspace as a file descriptor to allow passing
between devices, (2) fence, which provides a mechanism to signal when
one device as finished access, and (3) reservation, which manages the
shared or exclusive fence(s) associated with the buffer.
dma-buf
~~~~~~~
.. kernel-doc:: drivers/dma-buf/dma-buf.c
:export:
.. kernel-doc:: include/linux/dma-buf.h
:internal:
reservation
~~~~~~~~~~~
.. kernel-doc:: drivers/dma-buf/reservation.c
:doc: Reservation Object Overview
.. kernel-doc:: drivers/dma-buf/reservation.c
:export:
.. kernel-doc:: include/linux/reservation.h
:internal:
fence
~~~~~
.. kernel-doc:: drivers/dma-buf/fence.c
:export:
.. kernel-doc:: include/linux/fence.h
:internal:
.. kernel-doc:: drivers/dma-buf/seqno-fence.c
:export:
.. kernel-doc:: include/linux/seqno-fence.h
:internal:
.. kernel-doc:: drivers/dma-buf/fence-array.c
:export:
.. kernel-doc:: include/linux/fence-array.h
:internal:
.. kernel-doc:: drivers/dma-buf/reservation.c
:export:
.. kernel-doc:: include/linux/reservation.h
:internal:
.. kernel-doc:: drivers/dma-buf/sync_file.c
:export:
.. kernel-doc:: include/linux/sync_file.h
:internal:
Device Drivers DMA Management
-----------------------------
.. kernel-doc:: drivers/base/dma-coherent.c
:export:
.. kernel-doc:: drivers/base/dma-mapping.c
:export:
Device Drivers Power Management
-------------------------------
.. kernel-doc:: drivers/base/power/main.c
:export:
Device Drivers ACPI Support
---------------------------
.. kernel-doc:: drivers/acpi/scan.c
:export:
.. kernel-doc:: drivers/acpi/scan.c
:internal:
Device drivers PnP support
--------------------------
.. kernel-doc:: drivers/pnp/core.c
:internal:
.. kernel-doc:: drivers/pnp/card.c
:export:
.. kernel-doc:: drivers/pnp/driver.c
:internal:
.. kernel-doc:: drivers/pnp/manager.c
:export:
.. kernel-doc:: drivers/pnp/support.c
:export:
Userspace IO devices
--------------------
.. kernel-doc:: drivers/uio/uio.c
:export:
.. kernel-doc:: include/linux/uio_driver.h
:internal:

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@ -0,0 +1,51 @@
Input Subsystem
===============
Input core
----------
.. kernel-doc:: include/linux/input.h
:internal:
.. kernel-doc:: drivers/input/input.c
:export:
.. kernel-doc:: drivers/input/ff-core.c
:export:
.. kernel-doc:: drivers/input/ff-memless.c
:export:
Multitouch Library
------------------
.. kernel-doc:: include/linux/input/mt.h
:internal:
.. kernel-doc:: drivers/input/input-mt.c
:export:
Polled input devices
--------------------
.. kernel-doc:: include/linux/input-polldev.h
:internal:
.. kernel-doc:: drivers/input/input-polldev.c
:export:
Matrix keyboards/keypads
------------------------
.. kernel-doc:: include/linux/input/matrix_keypad.h
:internal:
Sparse keymap support
---------------------
.. kernel-doc:: include/linux/input/sparse-keymap.h
:internal:
.. kernel-doc:: drivers/input/sparse-keymap.c
:export:

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@ -0,0 +1,12 @@
Message-based devices
=====================
Fusion message devices
----------------------
.. kernel-doc:: drivers/message/fusion/mptbase.c
:export:
.. kernel-doc:: drivers/message/fusion/mptscsih.c
:export:

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@ -0,0 +1,50 @@
Parallel Port Devices
=====================
.. kernel-doc:: include/linux/parport.h
:internal:
.. kernel-doc:: drivers/parport/ieee1284.c
:export:
.. kernel-doc:: drivers/parport/share.c
:export:
.. kernel-doc:: drivers/parport/daisy.c
:internal:
16x50 UART Driver
=================
.. kernel-doc:: drivers/tty/serial/serial_core.c
:export:
.. kernel-doc:: drivers/tty/serial/8250/8250_core.c
:export:
Pulse-Width Modulation (PWM)
============================
Pulse-width modulation is a modulation technique primarily used to
control power supplied to electrical devices.
The PWM framework provides an abstraction for providers and consumers of
PWM signals. A controller that provides one or more PWM signals is
registered as :c:type:`struct pwm_chip <pwm_chip>`. Providers
are expected to embed this structure in a driver-specific structure.
This structure contains fields that describe a particular chip.
A chip exposes one or more PWM signal sources, each of which exposed as
a :c:type:`struct pwm_device <pwm_device>`. Operations can be
performed on PWM devices to control the period, duty cycle, polarity and
active state of the signal.
Note that PWM devices are exclusive resources: they can always only be
used by one consumer at a time.
.. kernel-doc:: include/linux/pwm.h
:internal:
.. kernel-doc:: drivers/pwm/core.c
:export:

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@ -0,0 +1,54 @@
Sound Devices
=============
.. kernel-doc:: include/sound/core.h
:internal:
.. kernel-doc:: sound/sound_core.c
:export:
.. kernel-doc:: include/sound/pcm.h
:internal:
.. kernel-doc:: sound/core/pcm.c
:export:
.. kernel-doc:: sound/core/device.c
:export:
.. kernel-doc:: sound/core/info.c
:export:
.. kernel-doc:: sound/core/rawmidi.c
:export:
.. kernel-doc:: sound/core/sound.c
:export:
.. kernel-doc:: sound/core/memory.c
:export:
.. kernel-doc:: sound/core/pcm_memory.c
:export:
.. kernel-doc:: sound/core/init.c
:export:
.. kernel-doc:: sound/core/isadma.c
:export:
.. kernel-doc:: sound/core/control.c
:export:
.. kernel-doc:: sound/core/pcm_lib.c
:export:
.. kernel-doc:: sound/core/hwdep.c
:export:
.. kernel-doc:: sound/core/pcm_native.c
:export:
.. kernel-doc:: sound/core/memalloc.c
:export:

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Serial Peripheral Interface (SPI)
=================================
SPI is the "Serial Peripheral Interface", widely used with embedded
systems because it is a simple and efficient interface: basically a
multiplexed shift register. Its three signal wires hold a clock (SCK,
often in the range of 1-20 MHz), a "Master Out, Slave In" (MOSI) data
line, and a "Master In, Slave Out" (MISO) data line. SPI is a full
duplex protocol; for each bit shifted out the MOSI line (one per clock)
another is shifted in on the MISO line. Those bits are assembled into
words of various sizes on the way to and from system memory. An
additional chipselect line is usually active-low (nCS); four signals are
normally used for each peripheral, plus sometimes an interrupt.
The SPI bus facilities listed here provide a generalized interface to
declare SPI busses and devices, manage them according to the standard
Linux driver model, and perform input/output operations. At this time,
only "master" side interfaces are supported, where Linux talks to SPI
peripherals and does not implement such a peripheral itself. (Interfaces
to support implementing SPI slaves would necessarily look different.)
The programming interface is structured around two kinds of driver, and
two kinds of device. A "Controller Driver" abstracts the controller
hardware, which may be as simple as a set of GPIO pins or as complex as
a pair of FIFOs connected to dual DMA engines on the other side of the
SPI shift register (maximizing throughput). Such drivers bridge between
whatever bus they sit on (often the platform bus) and SPI, and expose
the SPI side of their device as a :c:type:`struct spi_master
<spi_master>`. SPI devices are children of that master,
represented as a :c:type:`struct spi_device <spi_device>` and
manufactured from :c:type:`struct spi_board_info
<spi_board_info>` descriptors which are usually provided by
board-specific initialization code. A :c:type:`struct spi_driver
<spi_driver>` is called a "Protocol Driver", and is bound to a
spi_device using normal driver model calls.
The I/O model is a set of queued messages. Protocol drivers submit one
or more :c:type:`struct spi_message <spi_message>` objects,
which are processed and completed asynchronously. (There are synchronous
wrappers, however.) Messages are built from one or more
:c:type:`struct spi_transfer <spi_transfer>` objects, each of
which wraps a full duplex SPI transfer. A variety of protocol tweaking
options are needed, because different chips adopt very different
policies for how they use the bits transferred with SPI.
.. kernel-doc:: include/linux/spi/spi.h
:internal:
.. kernel-doc:: drivers/spi/spi.c
:functions: spi_register_board_info
.. kernel-doc:: drivers/spi/spi.c
:export:

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@ -50,7 +50,7 @@ Attributes of devices can be exported by a device driver through sysfs.
Please see Documentation/filesystems/sysfs.txt for more information
on how sysfs works.
As explained in Documentation/kobject.txt, device attributes must be be
As explained in Documentation/kobject.txt, device attributes must be
created before the KOBJ_ADD uevent is generated. The only way to realize
that is by defining an attribute group.

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@ -145,7 +145,7 @@ Table 1-1: Process specific entries in /proc
symbol the task is blocked in - or "0" if not blocked.
pagemap Page table
stack Report full stack trace, enable via CONFIG_STACKTRACE
smaps a extension based on maps, showing the memory consumption of
smaps an extension based on maps, showing the memory consumption of
each mapping and flags associated with it
numa_maps an extension based on maps, showing the memory locality and
binding policy as well as mem usage (in pages) of each mapping.

257
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Using gcov with the Linux kernel
================================
1. Introduction
2. Preparation
3. Customization
4. Files
5. Modules
6. Separated build and test machines
7. Troubleshooting
Appendix A: sample script: gather_on_build.sh
Appendix B: sample script: gather_on_test.sh
1. Introduction
===============
gcov profiling kernel support enables the use of GCC's coverage testing
tool gcov [1] with the Linux kernel. Coverage data of a running kernel
is exported in gcov-compatible format via the "gcov" debugfs directory.
To get coverage data for a specific file, change to the kernel build
directory and use gcov with the -o option as follows (requires root):
# cd /tmp/linux-out
# gcov -o /sys/kernel/debug/gcov/tmp/linux-out/kernel spinlock.c
This will create source code files annotated with execution counts
in the current directory. In addition, graphical gcov front-ends such
as lcov [2] can be used to automate the process of collecting data
for the entire kernel and provide coverage overviews in HTML format.
Possible uses:
* debugging (has this line been reached at all?)
* test improvement (how do I change my test to cover these lines?)
* minimizing kernel configurations (do I need this option if the
associated code is never run?)
--
[1] http://gcc.gnu.org/onlinedocs/gcc/Gcov.html
[2] http://ltp.sourceforge.net/coverage/lcov.php
2. Preparation
==============
Configure the kernel with:
CONFIG_DEBUG_FS=y
CONFIG_GCOV_KERNEL=y
select the gcc's gcov format, default is autodetect based on gcc version:
CONFIG_GCOV_FORMAT_AUTODETECT=y
and to get coverage data for the entire kernel:
CONFIG_GCOV_PROFILE_ALL=y
Note that kernels compiled with profiling flags will be significantly
larger and run slower. Also CONFIG_GCOV_PROFILE_ALL may not be supported
on all architectures.
Profiling data will only become accessible once debugfs has been
mounted:
mount -t debugfs none /sys/kernel/debug
3. Customization
================
To enable profiling for specific files or directories, add a line
similar to the following to the respective kernel Makefile:
For a single file (e.g. main.o):
GCOV_PROFILE_main.o := y
For all files in one directory:
GCOV_PROFILE := y
To exclude files from being profiled even when CONFIG_GCOV_PROFILE_ALL
is specified, use:
GCOV_PROFILE_main.o := n
and:
GCOV_PROFILE := n
Only files which are linked to the main kernel image or are compiled as
kernel modules are supported by this mechanism.
4. Files
========
The gcov kernel support creates the following files in debugfs:
/sys/kernel/debug/gcov
Parent directory for all gcov-related files.
/sys/kernel/debug/gcov/reset
Global reset file: resets all coverage data to zero when
written to.
/sys/kernel/debug/gcov/path/to/compile/dir/file.gcda
The actual gcov data file as understood by the gcov
tool. Resets file coverage data to zero when written to.
/sys/kernel/debug/gcov/path/to/compile/dir/file.gcno
Symbolic link to a static data file required by the gcov
tool. This file is generated by gcc when compiling with
option -ftest-coverage.
5. Modules
==========
Kernel modules may contain cleanup code which is only run during
module unload time. The gcov mechanism provides a means to collect
coverage data for such code by keeping a copy of the data associated
with the unloaded module. This data remains available through debugfs.
Once the module is loaded again, the associated coverage counters are
initialized with the data from its previous instantiation.
This behavior can be deactivated by specifying the gcov_persist kernel
parameter:
gcov_persist=0
At run-time, a user can also choose to discard data for an unloaded
module by writing to its data file or the global reset file.
6. Separated build and test machines
====================================
The gcov kernel profiling infrastructure is designed to work out-of-the
box for setups where kernels are built and run on the same machine. In
cases where the kernel runs on a separate machine, special preparations
must be made, depending on where the gcov tool is used:
a) gcov is run on the TEST machine
The gcov tool version on the test machine must be compatible with the
gcc version used for kernel build. Also the following files need to be
copied from build to test machine:
from the source tree:
- all C source files + headers
from the build tree:
- all C source files + headers
- all .gcda and .gcno files
- all links to directories
It is important to note that these files need to be placed into the
exact same file system location on the test machine as on the build
machine. If any of the path components is symbolic link, the actual
directory needs to be used instead (due to make's CURDIR handling).
b) gcov is run on the BUILD machine
The following files need to be copied after each test case from test
to build machine:
from the gcov directory in sysfs:
- all .gcda files
- all links to .gcno files
These files can be copied to any location on the build machine. gcov
must then be called with the -o option pointing to that directory.
Example directory setup on the build machine:
/tmp/linux: kernel source tree
/tmp/out: kernel build directory as specified by make O=
/tmp/coverage: location of the files copied from the test machine
[user@build] cd /tmp/out
[user@build] gcov -o /tmp/coverage/tmp/out/init main.c
7. Troubleshooting
==================
Problem: Compilation aborts during linker step.
Cause: Profiling flags are specified for source files which are not
linked to the main kernel or which are linked by a custom
linker procedure.
Solution: Exclude affected source files from profiling by specifying
GCOV_PROFILE := n or GCOV_PROFILE_basename.o := n in the
corresponding Makefile.
Problem: Files copied from sysfs appear empty or incomplete.
Cause: Due to the way seq_file works, some tools such as cp or tar
may not correctly copy files from sysfs.
Solution: Use 'cat' to read .gcda files and 'cp -d' to copy links.
Alternatively use the mechanism shown in Appendix B.
Appendix A: gather_on_build.sh
==============================
Sample script to gather coverage meta files on the build machine
(see 6a):
#!/bin/bash
KSRC=$1
KOBJ=$2
DEST=$3
if [ -z "$KSRC" ] || [ -z "$KOBJ" ] || [ -z "$DEST" ]; then
echo "Usage: $0 <ksrc directory> <kobj directory> <output.tar.gz>" >&2
exit 1
fi
KSRC=$(cd $KSRC; printf "all:\n\t@echo \${CURDIR}\n" | make -f -)
KOBJ=$(cd $KOBJ; printf "all:\n\t@echo \${CURDIR}\n" | make -f -)
find $KSRC $KOBJ \( -name '*.gcno' -o -name '*.[ch]' -o -type l \) -a \
-perm /u+r,g+r | tar cfz $DEST -P -T -
if [ $? -eq 0 ] ; then
echo "$DEST successfully created, copy to test system and unpack with:"
echo " tar xfz $DEST -P"
else
echo "Could not create file $DEST"
fi
Appendix B: gather_on_test.sh
=============================
Sample script to gather coverage data files on the test machine
(see 6b):
#!/bin/bash -e
DEST=$1
GCDA=/sys/kernel/debug/gcov
if [ -z "$DEST" ] ; then
echo "Usage: $0 <output.tar.gz>" >&2
exit 1
fi
TEMPDIR=$(mktemp -d)
echo Collecting data..
find $GCDA -type d -exec mkdir -p $TEMPDIR/\{\} \;
find $GCDA -name '*.gcda' -exec sh -c 'cat < $0 > '$TEMPDIR'/$0' {} \;
find $GCDA -name '*.gcno' -exec sh -c 'cp -d $0 '$TEMPDIR'/$0' {} \;
tar czf $DEST -C $TEMPDIR sys
rm -rf $TEMPDIR
echo "$DEST successfully created, copy to build system and unpack with:"
echo " tar xfz $DEST"

5
Documentation/gpu/conf.py Normal file
View File

@ -0,0 +1,5 @@
# -*- coding: utf-8; mode: python -*-
project = "Linux GPU Driver Developer's Guide"
tags.add("subproject")

7
Documentation/gpu/index.rst
View File

@ -12,3 +12,10 @@ Linux GPU Driver Developer's Guide
drm-uapi
i915
vga-switcheroo
.. only:: subproject
Indices
=======
* :ref:`genindex`

75
Documentation/hsi.txt
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@ -1,75 +0,0 @@
HSI - High-speed Synchronous Serial Interface
1. Introduction
~~~~~~~~~~~~~~~
High Speed Syncronous Interface (HSI) is a fullduplex, low latency protocol,
that is optimized for die-level interconnect between an Application Processor
and a Baseband chipset. It has been specified by the MIPI alliance in 2003 and
implemented by multiple vendors since then.
The HSI interface supports full duplex communication over multiple channels
(typically 8) and is capable of reaching speeds up to 200 Mbit/s.
The serial protocol uses two signals, DATA and FLAG as combined data and clock
signals and an additional READY signal for flow control. An additional WAKE
signal can be used to wakeup the chips from standby modes. The signals are
commonly prefixed by AC for signals going from the application die to the
cellular die and CA for signals going the other way around.
+------------+ +---------------+
| Cellular | | Application |
| Die | | Die |
| | - - - - - - CAWAKE - - - - - - >| |
| T|------------ CADATA ------------>|R |
| X|------------ CAFLAG ------------>|X |
| |<----------- ACREADY ------------| |
| | | |
| | | |
| |< - - - - - ACWAKE - - - - - - -| |
| R|<----------- ACDATA -------------|T |
| X|<----------- ACFLAG -------------|X |
| |------------ CAREADY ----------->| |
| | | |
| | | |
+------------+ +---------------+
2. HSI Subsystem in Linux
~~~~~~~~~~~~~~~~~~~~~~~~~
In the Linux kernel the hsi subsystem is supposed to be used for HSI devices.
The hsi subsystem contains drivers for hsi controllers including support for
multi-port controllers and provides a generic API for using the HSI ports.
It also contains HSI client drivers, which make use of the generic API to
implement a protocol used on the HSI interface. These client drivers can
use an arbitrary number of channels.
3. hsi-char Device
~~~~~~~~~~~~~~~~~~
Each port automatically registers a generic client driver called hsi_char,
which provides a charecter device for userspace representing the HSI port.
It can be used to communicate via HSI from userspace. Userspace may
configure the hsi_char device using the following ioctl commands:
* HSC_RESET:
- flush the HSI port
* HSC_SET_PM
- enable or disable the client.
* HSC_SEND_BREAK
- send break
* HSC_SET_RX
- set RX configuration
* HSC_GET_RX
- get RX configuration
* HSC_SET_TX
- set TX configuration
* HSC_GET_TX
- get TX configuration

10
Documentation/index.rst
View File

@ -6,22 +6,18 @@
Welcome to The Linux Kernel's documentation!
============================================
Nothing for you to see here *yet*. Please move along.
Contents:
.. toctree::
:maxdepth: 2
kernel-documentation
media/media_uapi
media/media_kapi
media/dvb-drivers/index
media/v4l-drivers/index
dev-tools/tools
driver-api/index
media/index
gpu/index
Indices and tables
==================
* :ref:`genindex`
* :ref:`search`

13
Documentation/ioctl/botching-up-ioctls.txt
View File

@ -34,15 +34,18 @@ will need to add a a 32-bit compat layer:
64-bit platforms do. So we always need padding to the natural size to get
this right.
* Pad the entire struct to a multiple of 64-bits - the structure size will
otherwise differ on 32-bit versus 64-bit. Having a different structure size
hurts when passing arrays of structures to the kernel, or if the kernel
checks the structure size, which e.g. the drm core does.
* Pad the entire struct to a multiple of 64-bits if the structure contains
64-bit types - the structure size will otherwise differ on 32-bit versus
64-bit. Having a different structure size hurts when passing arrays of
structures to the kernel, or if the kernel checks the structure size, which
e.g. the drm core does.
* Pointers are __u64, cast from/to a uintprt_t on the userspace side and
from/to a void __user * in the kernel. Try really hard not to delay this
conversion or worse, fiddle the raw __u64 through your code since that
diminishes the checking tools like sparse can provide.
diminishes the checking tools like sparse can provide. The macro
u64_to_user_ptr can be used in the kernel to avoid warnings about integers
and pointres of different sizes.
Basics

171
Documentation/kasan.txt
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@ -1,171 +0,0 @@
KernelAddressSanitizer (KASAN)
==============================
0. Overview
===========
KernelAddressSANitizer (KASAN) is a dynamic memory error detector. It provides
a fast and comprehensive solution for finding use-after-free and out-of-bounds
bugs.
KASAN uses compile-time instrumentation for checking every memory access,
therefore you will need a GCC version 4.9.2 or later. GCC 5.0 or later is
required for detection of out-of-bounds accesses to stack or global variables.
Currently KASAN is supported only for x86_64 architecture.
1. Usage
========
To enable KASAN configure kernel with:
CONFIG_KASAN = y
and choose between CONFIG_KASAN_OUTLINE and CONFIG_KASAN_INLINE. Outline and
inline are compiler instrumentation types. The former produces smaller binary
the latter is 1.1 - 2 times faster. Inline instrumentation requires a GCC
version 5.0 or later.
KASAN works with both SLUB and SLAB memory allocators.
For better bug detection and nicer reporting, enable CONFIG_STACKTRACE.
To disable instrumentation for specific files or directories, add a line
similar to the following to the respective kernel Makefile:
For a single file (e.g. main.o):
KASAN_SANITIZE_main.o := n
For all files in one directory:
KASAN_SANITIZE := n
1.1 Error reports
=================
A typical out of bounds access report looks like this:
==================================================================
BUG: AddressSanitizer: out of bounds access in kmalloc_oob_right+0x65/0x75 [test_kasan] at addr ffff8800693bc5d3
Write of size 1 by task modprobe/1689
=============================================================================
BUG kmalloc-128 (Not tainted): kasan error
-----------------------------------------------------------------------------
Disabling lock debugging due to kernel taint
INFO: Allocated in kmalloc_oob_right+0x3d/0x75 [test_kasan] age=0 cpu=0 pid=1689
__slab_alloc+0x4b4/0x4f0
kmem_cache_alloc_trace+0x10b/0x190
kmalloc_oob_right+0x3d/0x75 [test_kasan]
init_module+0x9/0x47 [test_kasan]
do_one_initcall+0x99/0x200
load_module+0x2cb3/0x3b20
SyS_finit_module+0x76/0x80
system_call_fastpath+0x12/0x17
INFO: Slab 0xffffea0001a4ef00 objects=17 used=7 fp=0xffff8800693bd728 flags=0x100000000004080
INFO: Object 0xffff8800693bc558 @offset=1368 fp=0xffff8800693bc720
Bytes b4 ffff8800693bc548: 00 00 00 00 00 00 00 00 5a 5a 5a 5a 5a 5a 5a 5a ........ZZZZZZZZ
Object ffff8800693bc558: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ffff8800693bc568: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ffff8800693bc578: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ffff8800693bc588: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ffff8800693bc598: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ffff8800693bc5a8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ffff8800693bc5b8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
Object ffff8800693bc5c8: 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b a5 kkkkkkkkkkkkkkk.
Redzone ffff8800693bc5d8: cc cc cc cc cc cc cc cc ........
Padding ffff8800693bc718: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ
CPU: 0 PID: 1689 Comm: modprobe Tainted: G B 3.18.0-rc1-mm1+ #98
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014
ffff8800693bc000 0000000000000000 ffff8800693bc558 ffff88006923bb78
ffffffff81cc68ae 00000000000000f3 ffff88006d407600 ffff88006923bba8
ffffffff811fd848 ffff88006d407600 ffffea0001a4ef00 ffff8800693bc558
Call Trace:
[<ffffffff81cc68ae>] dump_stack+0x46/0x58
[<ffffffff811fd848>] print_trailer+0xf8/0x160
[<ffffffffa00026a7>] ? kmem_cache_oob+0xc3/0xc3 [test_kasan]
[<ffffffff811ff0f5>] object_err+0x35/0x40
[<ffffffffa0002065>] ? kmalloc_oob_right+0x65/0x75 [test_kasan]
[<ffffffff8120b9fa>] kasan_report_error+0x38a/0x3f0
[<ffffffff8120a79f>] ? kasan_poison_shadow+0x2f/0x40
[<ffffffff8120b344>] ? kasan_unpoison_shadow+0x14/0x40
[<ffffffff8120a79f>] ? kasan_poison_shadow+0x2f/0x40
[<ffffffffa00026a7>] ? kmem_cache_oob+0xc3/0xc3 [test_kasan]
[<ffffffff8120a995>] __asan_store1+0x75/0xb0
[<ffffffffa0002601>] ? kmem_cache_oob+0x1d/0xc3 [test_kasan]
[<ffffffffa0002065>] ? kmalloc_oob_right+0x65/0x75 [test_kasan]
[<ffffffffa0002065>] kmalloc_oob_right+0x65/0x75 [test_kasan]
[<ffffffffa00026b0>] init_module+0x9/0x47 [test_kasan]
[<ffffffff810002d9>] do_one_initcall+0x99/0x200
[<ffffffff811e4e5c>] ? __vunmap+0xec/0x160
[<ffffffff81114f63>] load_module+0x2cb3/0x3b20
[<ffffffff8110fd70>] ? m_show+0x240/0x240
[<ffffffff81115f06>] SyS_finit_module+0x76/0x80
[<ffffffff81cd3129>] system_call_fastpath+0x12/0x17
Memory state around the buggy address:
ffff8800693bc300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8800693bc380: fc fc 00 00 00 00 00 00 00 00 00 00 00 00 00 fc
ffff8800693bc400: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8800693bc480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8800693bc500: fc fc fc fc fc fc fc fc fc fc fc 00 00 00 00 00
>ffff8800693bc580: 00 00 00 00 00 00 00 00 00 00 03 fc fc fc fc fc
^
ffff8800693bc600: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8800693bc680: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8800693bc700: fc fc fc fc fb fb fb fb fb fb fb fb fb fb fb fb
ffff8800693bc780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8800693bc800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
The header of the report discribe what kind of bug happened and what kind of
access caused it. It's followed by the description of the accessed slub object
(see 'SLUB Debug output' section in Documentation/vm/slub.txt for details) and
the description of the accessed memory page.
In the last section the report shows memory state around the accessed address.
Reading this part requires some understanding of how KASAN works.
The state of each 8 aligned bytes of memory is encoded in one shadow byte.
Those 8 bytes can be accessible, partially accessible, freed or be a redzone.
We use the following encoding for each shadow byte: 0 means that all 8 bytes
of the corresponding memory region are accessible; number N (1 <= N <= 7) means
that the first N bytes are accessible, and other (8 - N) bytes are not;
any negative value indicates that the entire 8-byte word is inaccessible.
We use different negative values to distinguish between different kinds of
inaccessible memory like redzones or freed memory (see mm/kasan/kasan.h).
In the report above the arrows point to the shadow byte 03, which means that
the accessed address is partially accessible.
2. Implementation details
=========================
From a high level, our approach to memory error detection is similar to that
of kmemcheck: use shadow memory to record whether each byte of memory is safe
to access, and use compile-time instrumentation to check shadow memory on each
memory access.
AddressSanitizer dedicates 1/8 of kernel memory to its shadow memory
(e.g. 16TB to cover 128TB on x86_64) and uses direct mapping with a scale and
offset to translate a memory address to its corresponding shadow address.
Here is the function which translates an address to its corresponding shadow
address:
static inline void *kasan_mem_to_shadow(const void *addr)
{
return ((unsigned long)addr >> KASAN_SHADOW_SCALE_SHIFT)
+ KASAN_SHADOW_OFFSET;
}
where KASAN_SHADOW_SCALE_SHIFT = 3.
Compile-time instrumentation used for checking memory accesses. Compiler inserts
function calls (__asan_load*(addr), __asan_store*(addr)) before each memory
access of size 1, 2, 4, 8 or 16. These functions check whether memory access is
valid or not by checking corresponding shadow memory.
GCC 5.0 has possibility to perform inline instrumentation. Instead of making
function calls GCC directly inserts the code to check the shadow memory.
This option significantly enlarges kernel but it gives x1.1-x2 performance
boost over outline instrumented kernel.

39
Documentation/kbuild/kconfig-language.txt
View File

@ -274,7 +274,44 @@ menuconfig:
This is similar to the simple config entry above, but it also gives a
hint to front ends, that all suboptions should be displayed as a
separate list of options.
separate list of options. To make sure all the suboptions will really
show up under the menuconfig entry and not outside of it, every item
from the <config options> list must depend on the menuconfig symbol.
In practice, this is achieved by using one of the next two constructs:
(1):
menuconfig M
if M
config C1
config C2
endif
(2):
menuconfig M
config C1
depends on M
config C2
depends on M
In the following examples (3) and (4), C1 and C2 still have the M
dependency, but will not appear under menuconfig M anymore, because
of C0, which doesn't depend on M:
(3):
menuconfig M
config C0
if M
config C1
config C2
endif
(4):
menuconfig M
config C0
config C1
depends on M
config C2
depends on M
choices:

29
Documentation/kernel-documentation.rst
View File

@ -107,6 +107,35 @@ Here are some specific guidelines for the kernel documentation:
the order as encountered."), having the higher levels the same overall makes
it easier to follow the documents.
the C domain
------------
The `Sphinx C Domain`_ (name c) is suited for documentation of C API. E.g. a
function prototype:
.. code-block:: rst
.. c:function:: int ioctl( int fd, int request )
The C domain of the kernel-doc has some additional features. E.g. you can
*rename* the reference name of a function with a common name like ``open`` or
``ioctl``:
.. code-block:: rst
.. c:function:: int ioctl( int fd, int request )
:name: VIDIOC_LOG_STATUS
The func-name (e.g. ioctl) remains in the output but the ref-name changed from
``ioctl`` to ``VIDIOC_LOG_STATUS``. The index entry for this function is also
changed to ``VIDIOC_LOG_STATUS`` and the function can now referenced by:
.. code-block:: rst
:c:func:`VIDIOC_LOG_STATUS`
list tables
-----------

24
Documentation/kernel-parameters.txt
View File

@ -1688,7 +1688,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
intel_idle.max_cstate= [KNL,HW,ACPI,X86]
0 disables intel_idle and fall back on acpi_idle.
1 to 6 specify maximum depth of C-state.
1 to 9 specify maximum depth of C-state.
intel_pstate= [X86]
disable
@ -2161,10 +2161,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
than or equal to this physical address is ignored.
maxcpus= [SMP] Maximum number of processors that an SMP kernel
should make use of. maxcpus=n : n >= 0 limits the
kernel to using 'n' processors. n=0 is a special case,
it is equivalent to "nosmp", which also disables
the IO APIC.
will bring up during bootup. maxcpus=n : n >= 0 limits
the kernel to bring up 'n' processors. Surely after
bootup you can bring up the other plugged cpu by executing
"echo 1 > /sys/devices/system/cpu/cpuX/online". So maxcpus
only takes effect during system bootup.
While n=0 is a special case, it is equivalent to "nosmp",
which also disables the IO APIC.
max_loop= [LOOP] The number of loop block devices that get
(loop.max_loop) unconditionally pre-created at init time. The default
@ -2571,8 +2574,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
nodelayacct [KNL] Disable per-task delay accounting
nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
nodsp [SH] Disable hardware DSP at boot time.
noefi Disable EFI runtime services support.
@ -2773,9 +2774,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
nr_cpus= [SMP] Maximum number of processors that an SMP kernel
could support. nr_cpus=n : n >= 1 limits the kernel to
supporting 'n' processors. Later in runtime you can not
use hotplug cpu feature to put more cpu back to online.
just like you compile the kernel NR_CPUS=n
support 'n' processors. It could be larger than the
number of already plugged CPU during bootup, later in
runtime you can physically add extra cpu until it reaches
n. So during boot up some boot time memory for per-cpu
variables need be pre-allocated for later physical cpu
hot plugging.
nr_uarts= [SERIAL] maximum number of UARTs to be registered.

754
Documentation/kmemcheck.txt
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@ -1,754 +0,0 @@
GETTING STARTED WITH KMEMCHECK
==============================
Vegard Nossum <vegardno@ifi.uio.no>
Contents
========
0. Introduction
1. Downloading
2. Configuring and compiling
3. How to use
3.1. Booting
3.2. Run-time enable/disable
3.3. Debugging
3.4. Annotating false positives
4. Reporting errors
5. Technical description
0. Introduction
===============
kmemcheck is a debugging feature for the Linux Kernel. More specifically, it
is a dynamic checker that detects and warns about some uses of uninitialized
memory.
Userspace programmers might be familiar with Valgrind's memcheck. The main
difference between memcheck and kmemcheck is that memcheck works for userspace
programs only, and kmemcheck works for the kernel only. The implementations
are of course vastly different. Because of this, kmemcheck is not as accurate
as memcheck, but it turns out to be good enough in practice to discover real
programmer errors that the compiler is not able to find through static
analysis.
Enabling kmemcheck on a kernel will probably slow it down to the extent that
the machine will not be usable for normal workloads such as e.g. an
interactive desktop. kmemcheck will also cause the kernel to use about twice
as much memory as normal. For this reason, kmemcheck is strictly a debugging
feature.
1. Downloading
==============
As of version 2.6.31-rc1, kmemcheck is included in the mainline kernel.
2. Configuring and compiling
============================
kmemcheck only works for the x86 (both 32- and 64-bit) platform. A number of
configuration variables must have specific settings in order for the kmemcheck
menu to even appear in "menuconfig". These are:
o CONFIG_CC_OPTIMIZE_FOR_SIZE=n
This option is located under "General setup" / "Optimize for size".
Without this, gcc will use certain optimizations that usually lead to
false positive warnings from kmemcheck. An example of this is a 16-bit
field in a struct, where gcc may load 32 bits, then discard the upper
16 bits. kmemcheck sees only the 32-bit load, and may trigger a
warning for the upper 16 bits (if they're uninitialized).
o CONFIG_SLAB=y or CONFIG_SLUB=y
This option is located under "General setup" / "Choose SLAB
allocator".
o CONFIG_FUNCTION_TRACER=n
This option is located under "Kernel hacking" / "Tracers" / "Kernel
Function Tracer"
When function tracing is compiled in, gcc emits a call to another
function at the beginning of every function. This means that when the
page fault handler is called, the ftrace framework will be called
before kmemcheck has had a chance to handle the fault. If ftrace then
modifies memory that was tracked by kmemcheck, the result is an
endless recursive page fault.
o CONFIG_DEBUG_PAGEALLOC=n
This option is located under "Kernel hacking" / "Memory Debugging"
/ "Debug page memory allocations".
In addition, I highly recommend turning on CONFIG_DEBUG_INFO=y. This is also
located under "Kernel hacking". With this, you will be able to get line number
information from the kmemcheck warnings, which is extremely valuable in
debugging a problem. This option is not mandatory, however, because it slows
down the compilation process and produces a much bigger kernel image.
Now the kmemcheck menu should be visible (under "Kernel hacking" / "Memory
Debugging" / "kmemcheck: trap use of uninitialized memory"). Here follows
a description of the kmemcheck configuration variables:
o CONFIG_KMEMCHECK
This must be enabled in order to use kmemcheck at all...
o CONFIG_KMEMCHECK_[DISABLED | ENABLED | ONESHOT]_BY_DEFAULT
This option controls the status of kmemcheck at boot-time. "Enabled"
will enable kmemcheck right from the start, "disabled" will boot the
kernel as normal (but with the kmemcheck code compiled in, so it can
be enabled at run-time after the kernel has booted), and "one-shot" is
a special mode which will turn kmemcheck off automatically after
detecting the first use of uninitialized memory.
If you are using kmemcheck to actively debug a problem, then you
probably want to choose "enabled" here.
The one-shot mode is mostly useful in automated test setups because it
can prevent floods of warnings and increase the chances of the machine
surviving in case something is really wrong. In other cases, the one-
shot mode could actually be counter-productive because it would turn
itself off at the very first error -- in the case of a false positive
too -- and this would come in the way of debugging the specific
problem you were interested in.
If you would like to use your kernel as normal, but with a chance to
enable kmemcheck in case of some problem, it might be a good idea to
choose "disabled" here. When kmemcheck is disabled, most of the run-
time overhead is not incurred, and the kernel will be almost as fast
as normal.
o CONFIG_KMEMCHECK_QUEUE_SIZE
Select the maximum number of error reports to store in an internal
(fixed-size) buffer. Since errors can occur virtually anywhere and in
any context, we need a temporary storage area which is guaranteed not
to generate any other page faults when accessed. The queue will be
emptied as soon as a tasklet may be scheduled. If the queue is full,
new error reports will be lost.
The default value of 64 is probably fine. If some code produces more
than 64 errors within an irqs-off section, then the code is likely to
produce many, many more, too, and these additional reports seldom give
any more information (the first report is usually the most valuable
anyway).
This number might have to be adjusted if you are not using serial
console or similar to capture the kernel log. If you are using the
"dmesg" command to save the log, then getting a lot of kmemcheck
warnings might overflow the kernel log itself, and the earlier reports
will get lost in that way instead. Try setting this to 10 or so on
such a setup.
o CONFIG_KMEMCHECK_SHADOW_COPY_SHIFT
Select the number of shadow bytes to save along with each entry of the
error-report queue. These bytes indicate what parts of an allocation
are initialized, uninitialized, etc. and will be displayed when an
error is detected to help the debugging of a particular problem.
The number entered here is actually the logarithm of the number of
bytes that will be saved. So if you pick for example 5 here, kmemcheck
will save 2^5 = 32 bytes.
The default value should be fine for debugging most problems. It also
fits nicely within 80 columns.
o CONFIG_KMEMCHECK_PARTIAL_OK
This option (when enabled) works around certain GCC optimizations that
produce 32-bit reads from 16-bit variables where the upper 16 bits are
thrown away afterwards.
The default value (enabled) is recommended. This may of course hide
some real errors, but disabling it would probably produce a lot of
false positives.
o CONFIG_KMEMCHECK_BITOPS_OK
This option silences warnings that would be generated for bit-field
accesses where not all the bits are initialized at the same time. This
may also hide some real bugs.
This option is probably obsolete, or it should be replaced with
the kmemcheck-/bitfield-annotations for the code in question. The
default value is therefore fine.
Now compile the kernel as usual.
3. How to use
=============
3.1. Booting
============
First some information about the command-line options. There is only one
option specific to kmemcheck, and this is called "kmemcheck". It can be used
to override the default mode as chosen by the CONFIG_KMEMCHECK_*_BY_DEFAULT
option. Its possible settings are:
o kmemcheck=0 (disabled)
o kmemcheck=1 (enabled)
o kmemcheck=2 (one-shot mode)
If SLUB debugging has been enabled in the kernel, it may take precedence over
kmemcheck in such a way that the slab caches which are under SLUB debugging
will not be tracked by kmemcheck. In order to ensure that this doesn't happen
(even though it shouldn't by default), use SLUB's boot option "slub_debug",
like this: slub_debug=-
In fact, this option may also be used for fine-grained control over SLUB vs.
kmemcheck. For example, if the command line includes "kmemcheck=1
slub_debug=,dentry", then SLUB debugging will be used only for the "dentry"
slab cache, and with kmemcheck tracking all the other caches. This is advanced
usage, however, and is not generally recommended.
3.2. Run-time enable/disable
============================
When the kernel has booted, it is possible to enable or disable kmemcheck at
run-time. WARNING: This feature is still experimental and may cause false
positive warnings to appear. Therefore, try not to use this. If you find that
it doesn't work properly (e.g. you see an unreasonable amount of warnings), I
will be happy to take bug reports.
Use the file /proc/sys/kernel/kmemcheck for this purpose, e.g.:
$ echo 0 > /proc/sys/kernel/kmemcheck # disables kmemcheck
The numbers are the same as for the kmemcheck= command-line option.
3.3. Debugging
==============
A typical report will look something like this:
WARNING: kmemcheck: Caught 32-bit read from uninitialized memory (ffff88003e4a2024)
80000000000000000000000000000000000000000088ffff0000000000000000
i i i i u u u u i i i i i i i i u u u u u u u u u u u u u u u u
^
Pid: 1856, comm: ntpdate Not tainted 2.6.29-rc5 #264 945P-A
RIP: 0010:[<ffffffff8104ede8>] [<ffffffff8104ede8>] __dequeue_signal+0xc8/0x190
RSP: 0018:ffff88003cdf7d98 EFLAGS: 00210002
RAX: 0000000000000030 RBX: ffff88003d4ea968 RCX: 0000000000000009
RDX: ffff88003e5d6018 RSI: ffff88003e5d6024 RDI: ffff88003cdf7e84
RBP: ffff88003cdf7db8 R08: ffff88003e5d6000 R09: 0000000000000000
R10: 0000000000000080 R11: 0000000000000000 R12: 000000000000000e
R13: ffff88003cdf7e78 R14: ffff88003d530710 R15: ffff88003d5a98c8
FS: 0000000000000000(0000) GS:ffff880001982000(0063) knlGS:00000
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: ffff88003f806ea0 CR3: 000000003c036000 CR4: 00000000000006a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff4ff0 DR7: 0000000000000400
[<ffffffff8104f04e>] dequeue_signal+0x8e/0x170
[<ffffffff81050bd8>] get_signal_to_deliver+0x98/0x390
[<ffffffff8100b87d>] do_notify_resume+0xad/0x7d0
[<ffffffff8100c7b5>] int_signal+0x12/0x17
[<ffffffffffffffff>] 0xffffffffffffffff
The single most valuable information in this report is the RIP (or EIP on 32-
bit) value. This will help us pinpoint exactly which instruction that caused
the warning.
If your kernel was compiled with CONFIG_DEBUG_INFO=y, then all we have to do
is give this address to the addr2line program, like this:
$ addr2line -e vmlinux -i ffffffff8104ede8
arch/x86/include/asm/string_64.h:12
include/asm-generic/siginfo.h:287
kernel/signal.c:380
kernel/signal.c:410
The "-e vmlinux" tells addr2line which file to look in. IMPORTANT: This must
be the vmlinux of the kernel that produced the warning in the first place! If
not, the line number information will almost certainly be wrong.
The "-i" tells addr2line to also print the line numbers of inlined functions.
In this case, the flag was very important, because otherwise, it would only
have printed the first line, which is just a call to memcpy(), which could be
called from a thousand places in the kernel, and is therefore not very useful.
These inlined functions would not show up in the stack trace above, simply
because the kernel doesn't load the extra debugging information. This
technique can of course be used with ordinary kernel oopses as well.
In this case, it's the caller of memcpy() that is interesting, and it can be
found in include/asm-generic/siginfo.h, line 287:
281 static inline void copy_siginfo(struct siginfo *to, struct siginfo *from)
282 {
283 if (from->si_code < 0)
284 memcpy(to, from, sizeof(*to));
285 else
286 /* _sigchld is currently the largest know union member */
287 memcpy(to, from, __ARCH_SI_PREAMBLE_SIZE + sizeof(from->_sifields._sigchld));
288 }
Since this was a read (kmemcheck usually warns about reads only, though it can
warn about writes to unallocated or freed memory as well), it was probably the
"from" argument which contained some uninitialized bytes. Following the chain
of calls, we move upwards to see where "from" was allocated or initialized,
kernel/signal.c, line 380:
359 static void collect_signal(int sig, struct sigpending *list, siginfo_t *info)
360 {
...
367 list_for_each_entry(q, &list->list, list) {
368 if (q->info.si_signo == sig) {
369 if (first)
370 goto still_pending;
371 first = q;
...
377 if (first) {
378 still_pending:
379 list_del_init(&first->list);
380 copy_siginfo(info, &first->info);
381 __sigqueue_free(first);
...
392 }
393 }
Here, it is &first->info that is being passed on to copy_siginfo(). The
variable "first" was found on a list -- passed in as the second argument to
collect_signal(). We continue our journey through the stack, to figure out
where the item on "list" was allocated or initialized. We move to line 410:
395 static int __dequeue_signal(struct sigpending *pending, sigset_t *mask,
396 siginfo_t *info)
397 {
...
410 collect_signal(sig, pending, info);
...
414 }
Now we need to follow the "pending" pointer, since that is being passed on to
collect_signal() as "list". At this point, we've run out of lines from the
"addr2line" output. Not to worry, we just paste the next addresses from the
kmemcheck stack dump, i.e.:
[<ffffffff8104f04e>] dequeue_signal+0x8e/0x170
[<ffffffff81050bd8>] get_signal_to_deliver+0x98/0x390
[<ffffffff8100b87d>] do_notify_resume+0xad/0x7d0
[<ffffffff8100c7b5>] int_signal+0x12/0x17
$ addr2line -e vmlinux -i ffffffff8104f04e ffffffff81050bd8 \
ffffffff8100b87d ffffffff8100c7b5
kernel/signal.c:446
kernel/signal.c:1806
arch/x86/kernel/signal.c:805
arch/x86/kernel/signal.c:871
arch/x86/kernel/entry_64.S:694
Remember that since these addresses were found on the stack and not as the
RIP value, they actually point to the _next_ instruction (they are return
addresses). This becomes obvious when we look at the code for line 446:
422 int dequeue_signal(struct task_struct *tsk, sigset_t *mask, siginfo_t *info)
423 {
...
431 signr = __dequeue_signal(&tsk->signal->shared_pending,
432 mask, info);
433 /*
434 * itimer signal ?
435 *
436 * itimers are process shared and we restart periodic
437 * itimers in the signal delivery path to prevent DoS
438 * attacks in the high resolution timer case. This is
439 * compliant with the old way of self restarting
440 * itimers, as the SIGALRM is a legacy signal and only
441 * queued once. Changing the restart behaviour to
442 * restart the timer in the signal dequeue path is
443 * reducing the timer noise on heavy loaded !highres
444 * systems too.
445 */
446 if (unlikely(signr == SIGALRM)) {
...
489 }
So instead of looking at 446, we should be looking at 431, which is the line
that executes just before 446. Here we see that what we are looking for is
&tsk->signal->shared_pending.
Our next task is now to figure out which function that puts items on this
"shared_pending" list. A crude, but efficient tool, is git grep:
$ git grep -n 'shared_pending' kernel/
...
kernel/signal.c:828: pending = group ? &t->signal->shared_pending : &t->pending;
kernel/signal.c:1339: pending = group ? &t->signal->shared_pending : &t->pending;
...
There were more results, but none of them were related to list operations,
and these were the only assignments. We inspect the line numbers more closely
and find that this is indeed where items are being added to the list:
816 static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
817 int group)
818 {
...
828 pending = group ? &t->signal->shared_pending : &t->pending;
...
851 q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN &&
852 (is_si_special(info) ||
853 info->si_code >= 0)));
854 if (q) {
855 list_add_tail(&q->list, &pending->list);
...
890 }
and:
1309 int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group)
1310 {
....
1339 pending = group ? &t->signal->shared_pending : &t->pending;
1340 list_add_tail(&q->list, &pending->list);
....
1347 }
In the first case, the list element we are looking for, "q", is being returned
from the function __sigqueue_alloc(), which looks like an allocation function.
Let's take a look at it:
187 static struct sigqueue *__sigqueue_alloc(struct task_struct *t, gfp_t flags,
188 int override_rlimit)
189 {
190 struct sigqueue *q = NULL;
191 struct user_struct *user;
192
193 /*
194 * We won't get problems with the target's UID changing under us
195 * because changing it requires RCU be used, and if t != current, the
196 * caller must be holding the RCU readlock (by way of a spinlock) and
197 * we use RCU protection here
198 */
199 user = get_uid(__task_cred(t)->user);
200 atomic_inc(&user->sigpending);
201 if (override_rlimit ||
202 atomic_read(&user->sigpending) <=
203 t->signal->rlim[RLIMIT_SIGPENDING].rlim_cur)
204 q = kmem_cache_alloc(sigqueue_cachep, flags);
205 if (unlikely(q == NULL)) {
206 atomic_dec(&user->sigpending);
207 free_uid(user);
208 } else {
209 INIT_LIST_HEAD(&q->list);
210 q->flags = 0;
211 q->user = user;
212 }
213
214 return q;
215 }
We see that this function initializes q->list, q->flags, and q->user. It seems
that now is the time to look at the definition of "struct sigqueue", e.g.:
14 struct sigqueue {
15 struct list_head list;
16 int flags;
17 siginfo_t info;
18 struct user_struct *user;
19 };
And, you might remember, it was a memcpy() on &first->info that caused the
warning, so this makes perfect sense. It also seems reasonable to assume that
it is the caller of __sigqueue_alloc() that has the responsibility of filling
out (initializing) this member.
But just which fields of the struct were uninitialized? Let's look at
kmemcheck's report again:
WARNING: kmemcheck: Caught 32-bit read from uninitialized memory (ffff88003e4a2024)
80000000000000000000000000000000000000000088ffff0000000000000000
i i i i u u u u i i i i i i i i u u u u u u u u u u u u u u u u
^
These first two lines are the memory dump of the memory object itself, and the
shadow bytemap, respectively. The memory object itself is in this case
&first->info. Just beware that the start of this dump is NOT the start of the
object itself! The position of the caret (^) corresponds with the address of
the read (ffff88003e4a2024).
The shadow bytemap dump legend is as follows:
i - initialized
u - uninitialized
a - unallocated (memory has been allocated by the slab layer, but has not
yet been handed off to anybody)
f - freed (memory has been allocated by the slab layer, but has been freed
by the previous owner)
In order to figure out where (relative to the start of the object) the
uninitialized memory was located, we have to look at the disassembly. For
that, we'll need the RIP address again:
RIP: 0010:[<ffffffff8104ede8>] [<ffffffff8104ede8>] __dequeue_signal+0xc8/0x190
$ objdump -d --no-show-raw-insn vmlinux | grep -C 8 ffffffff8104ede8:
ffffffff8104edc8: mov %r8,0x8(%r8)
ffffffff8104edcc: test %r10d,%r10d
ffffffff8104edcf: js ffffffff8104ee88 <__dequeue_signal+0x168>
ffffffff8104edd5: mov %rax,%rdx
ffffffff8104edd8: mov $0xc,%ecx
ffffffff8104eddd: mov %r13,%rdi
ffffffff8104ede0: mov $0x30,%eax
ffffffff8104ede5: mov %rdx,%rsi
ffffffff8104ede8: rep movsl %ds:(%rsi),%es:(%rdi)
ffffffff8104edea: test $0x2,%al
ffffffff8104edec: je ffffffff8104edf0 <__dequeue_signal+0xd0>
ffffffff8104edee: movsw %ds:(%rsi),%es:(%rdi)
ffffffff8104edf0: test $0x1,%al
ffffffff8104edf2: je ffffffff8104edf5 <__dequeue_signal+0xd5>
ffffffff8104edf4: movsb %ds:(%rsi),%es:(%rdi)
ffffffff8104edf5: mov %r8,%rdi
ffffffff8104edf8: callq ffffffff8104de60 <__sigqueue_free>
As expected, it's the "rep movsl" instruction from the memcpy() that causes
the warning. We know about REP MOVSL that it uses the register RCX to count
the number of remaining iterations. By taking a look at the register dump
again (from the kmemcheck report), we can figure out how many bytes were left
to copy:
RAX: 0000000000000030 RBX: ffff88003d4ea968 RCX: 0000000000000009
By looking at the disassembly, we also see that %ecx is being loaded with the
value $0xc just before (ffffffff8104edd8), so we are very lucky. Keep in mind
that this is the number of iterations, not bytes. And since this is a "long"
operation, we need to multiply by 4 to get the number of bytes. So this means
that the uninitialized value was encountered at 4 * (0xc - 0x9) = 12 bytes
from the start of the object.
We can now try to figure out which field of the "struct siginfo" that was not
initialized. This is the beginning of the struct:
40 typedef struct siginfo {
41 int si_signo;
42 int si_errno;
43 int si_code;
44
45 union {
..
92 } _sifields;
93 } siginfo_t;
On 64-bit, the int is 4 bytes long, so it must the union member that has
not been initialized. We can verify this using gdb:
$ gdb vmlinux
...
(gdb) p &((struct siginfo *) 0)->_sifields
$1 = (union {...} *) 0x10
Actually, it seems that the union member is located at offset 0x10 -- which
means that gcc has inserted 4 bytes of padding between the members si_code
and _sifields. We can now get a fuller picture of the memory dump:
_----------------------------=> si_code
/ _--------------------=> (padding)
| / _------------=> _sifields(._kill._pid)
| | / _----=> _sifields(._kill._uid)
| | | /
-------|-------|-------|-------|
80000000000000000000000000000000000000000088ffff0000000000000000
i i i i u u u u i i i i i i i i u u u u u u u u u u u u u u u u
This allows us to realize another important fact: si_code contains the value
0x80. Remember that x86 is little endian, so the first 4 bytes "80000000" are
really the number 0x00000080. With a bit of research, we find that this is
actually the constant SI_KERNEL defined in include/asm-generic/siginfo.h:
144 #define SI_KERNEL 0x80 /* sent by the kernel from somewhere */
This macro is used in exactly one place in the x86 kernel: In send_signal()
in kernel/signal.c:
816 static int send_signal(int sig, struct siginfo *info, struct task_struct *t,
817 int group)
818 {
...
828 pending = group ? &t->signal->shared_pending : &t->pending;
...
851 q = __sigqueue_alloc(t, GFP_ATOMIC, (sig < SIGRTMIN &&
852 (is_si_special(info) ||
853 info->si_code >= 0)));
854 if (q) {
855 list_add_tail(&q->list, &pending->list);
856 switch ((unsigned long) info) {
...
865 case (unsigned long) SEND_SIG_PRIV:
866 q->info.si_signo = sig;
867 q->info.si_errno = 0;
868 q->info.si_code = SI_KERNEL;
869 q->info.si_pid = 0;
870 q->info.si_uid = 0;
871 break;
...
890 }
Not only does this match with the .si_code member, it also matches the place
we found earlier when looking for where siginfo_t objects are enqueued on the
"shared_pending" list.
So to sum up: It seems that it is the padding introduced by the compiler
between two struct fields that is uninitialized, and this gets reported when
we do a memcpy() on the struct. This means that we have identified a false
positive warning.
Normally, kmemcheck will not report uninitialized accesses in memcpy() calls
when both the source and destination addresses are tracked. (Instead, we copy
the shadow bytemap as well). In this case, the destination address clearly
was not tracked. We can dig a little deeper into the stack trace from above:
arch/x86/kernel/signal.c:805
arch/x86/kernel/signal.c:871
arch/x86/kernel/entry_64.S:694
And we clearly see that the destination siginfo object is located on the
stack:
782 static void do_signal(struct pt_regs *regs)
783 {
784 struct k_sigaction ka;
785 siginfo_t info;
...
804 signr = get_signal_to_deliver(&info, &ka, regs, NULL);
...
854 }
And this &info is what eventually gets passed to copy_siginfo() as the
destination argument.
Now, even though we didn't find an actual error here, the example is still a
good one, because it shows how one would go about to find out what the report
was all about.
3.4. Annotating false positives
===============================
There are a few different ways to make annotations in the source code that
will keep kmemcheck from checking and reporting certain allocations. Here
they are:
o __GFP_NOTRACK_FALSE_POSITIVE
This flag can be passed to kmalloc() or kmem_cache_alloc() (therefore
also to other functions that end up calling one of these) to indicate
that the allocation should not be tracked because it would lead to
a false positive report. This is a "big hammer" way of silencing
kmemcheck; after all, even if the false positive pertains to
particular field in a struct, for example, we will now lose the
ability to find (real) errors in other parts of the same struct.
Example:
/* No warnings will ever trigger on accessing any part of x */
x = kmalloc(sizeof *x, GFP_KERNEL | __GFP_NOTRACK_FALSE_POSITIVE);
o kmemcheck_bitfield_begin(name)/kmemcheck_bitfield_end(name) and
kmemcheck_annotate_bitfield(ptr, name)
The first two of these three macros can be used inside struct
definitions to signal, respectively, the beginning and end of a
bitfield. Additionally, this will assign the bitfield a name, which
is given as an argument to the macros.
Having used these markers, one can later use
kmemcheck_annotate_bitfield() at the point of allocation, to indicate
which parts of the allocation is part of a bitfield.
Example:
struct foo {
int x;
kmemcheck_bitfield_begin(flags);
int flag_a:1;
int flag_b:1;
kmemcheck_bitfield_end(flags);
int y;
};
struct foo *x = kmalloc(sizeof *x);
/* No warnings will trigger on accessing the bitfield of x */
kmemcheck_annotate_bitfield(x, flags);
Note that kmemcheck_annotate_bitfield() can be used even before the
return value of kmalloc() is checked -- in other words, passing NULL
as the first argument is legal (and will do nothing).
4. Reporting errors
===================
As we have seen, kmemcheck will produce false positive reports. Therefore, it
is not very wise to blindly post kmemcheck warnings to mailing lists and
maintainers. Instead, I encourage maintainers and developers to find errors
in their own code. If you get a warning, you can try to work around it, try
to figure out if it's a real error or not, or simply ignore it. Most
developers know their own code and will quickly and efficiently determine the
root cause of a kmemcheck report. This is therefore also the most efficient
way to work with kmemcheck.
That said, we (the kmemcheck maintainers) will always be on the lookout for
false positives that we can annotate and silence. So whatever you find,
please drop us a note privately! Kernel configs and steps to reproduce (if
available) are of course a great help too.
Happy hacking!
5. Technical description
========================
kmemcheck works by marking memory pages non-present. This means that whenever
somebody attempts to access the page, a page fault is generated. The page
fault handler notices that the page was in fact only hidden, and so it calls
on the kmemcheck code to make further investigations.
When the investigations are completed, kmemcheck "shows" the page by marking
it present (as it would be under normal circumstances). This way, the
interrupted code can continue as usual.
But after the instruction has been executed, we should hide the page again, so
that we can catch the next access too! Now kmemcheck makes use of a debugging
feature of the processor, namely single-stepping. When the processor has
finished the one instruction that generated the memory access, a debug
exception is raised. From here, we simply hide the page again and continue
execution, this time with the single-stepping feature turned off.
kmemcheck requires some assistance from the memory allocator in order to work.
The memory allocator needs to
1. Tell kmemcheck about newly allocated pages and pages that are about to
be freed. This allows kmemcheck to set up and tear down the shadow memory
for the pages in question. The shadow memory stores the status of each
byte in the allocation proper, e.g. whether it is initialized or
uninitialized.
2. Tell kmemcheck which parts of memory should be marked uninitialized.
There are actually a few more states, such as "not yet allocated" and
"recently freed".
If a slab cache is set up using the SLAB_NOTRACK flag, it will never return
memory that can take page faults because of kmemcheck.
If a slab cache is NOT set up using the SLAB_NOTRACK flag, callers can still
request memory with the __GFP_NOTRACK or __GFP_NOTRACK_FALSE_POSITIVE flags.
This does not prevent the page faults from occurring, however, but marks the
object in question as being initialized so that no warnings will ever be
produced for this object.
Currently, the SLAB and SLUB allocators are supported by kmemcheck.

10
Documentation/kprobes.txt
View File

@ -103,6 +103,16 @@ Note that the probed function's args may be passed on the stack
or in registers. The jprobe will work in either case, so long as the
handler's prototype matches that of the probed function.
Note that in some architectures (e.g.: arm64 and sparc64) the stack
copy is not done, as the actual location of stacked parameters may be
outside of a reasonable MAX_STACK_SIZE value and because that location
cannot be determined by the jprobes code. In this case the jprobes
user must be careful to make certain the calling signature of the
function does not cause parameters to be passed on the stack (e.g.:
more than eight function arguments, an argument of more than sixteen
bytes, or more than 64 bytes of argument data, depending on
architecture).
1.3 Return Probes
1.3.1 How Does a Return Probe Work?

3
Documentation/media/Makefile
View File

@ -10,7 +10,8 @@ FILES = audio.h.rst ca.h.rst dmx.h.rst frontend.h.rst net.h.rst video.h.rst \
TARGETS := $(addprefix $(BUILDDIR)/, $(FILES))
htmldocs: $(BUILDDIR) ${TARGETS}
.PHONY: all
all: $(BUILDDIR) ${TARGETS}
$(BUILDDIR):
$(Q)mkdir -p $@

6
Documentation/media/audio.h.rst.exceptions
View File

@ -2,7 +2,7 @@
ignore define _DVBAUDIO_H_
# Typedef pointing to structs
replace typedef audio_karaoke_t audio-karaoke
replace typedef audio_karaoke_t :c:type:`audio_karaoke`
# Undocumented audio caps, as this is a deprecated API anyway
ignore define AUDIO_CAP_DTS
@ -16,5 +16,5 @@ ignore define AUDIO_CAP_SDDS
ignore define AUDIO_CAP_AC3
# some typedefs should point to struct/enums
replace typedef audio_mixer_t audio-mixer
replace typedef audio_status_t audio-status
replace typedef audio_mixer_t :c:type:`audio_mixer`
replace typedef audio_status_t :c:type:`audio_status`

32
Documentation/media/ca.h.rst.exceptions
View File

@ -2,23 +2,23 @@
ignore define _DVBCA_H_
# struct ca_slot_info defines
replace define CA_CI ca-slot-info
replace define CA_CI_LINK ca-slot-info
replace define CA_CI_PHYS ca-slot-info
replace define CA_DESCR ca-slot-info
replace define CA_SC ca-slot-info
replace define CA_CI_MODULE_PRESENT ca-slot-info
replace define CA_CI_MODULE_READY ca-slot-info
replace define CA_CI :c:type:`ca_slot_info`
replace define CA_CI_LINK :c:type:`ca_slot_info`
replace define CA_CI_PHYS :c:type:`ca_slot_info`
replace define CA_DESCR :c:type:`ca_slot_info`
replace define CA_SC :c:type:`ca_slot_info`
replace define CA_CI_MODULE_PRESENT :c:type:`ca_slot_info`
replace define CA_CI_MODULE_READY :c:type:`ca_slot_info`
# struct ca_descr_info defines
replace define CA_ECD ca-descr-info
replace define CA_NDS ca-descr-info
replace define CA_DSS ca-descr-info
replace define CA_ECD :c:type:`ca_descr_info`
replace define CA_NDS :c:type:`ca_descr_info`
replace define CA_DSS :c:type:`ca_descr_info`
# some typedefs should point to struct/enums
replace typedef ca_pid_t ca-pid
replace typedef ca_slot_info_t ca-slot-info
replace typedef ca_descr_info_t ca-descr-info
replace typedef ca_caps_t ca-caps
replace typedef ca_msg_t ca-msg
replace typedef ca_descr_t ca-descr
replace typedef ca_pid_t :c:type:`ca_pid`
replace typedef ca_slot_info_t :c:type:`ca_slot_info`
replace typedef ca_descr_info_t :c:type:`ca_descr_info`
replace typedef ca_caps_t :c:type:`ca_caps`
replace typedef ca_msg_t :c:type:`ca_msg`
replace typedef ca_descr_t :c:type:`ca_descr`

6
Documentation/media/cec.h.rst.exceptions
View File

@ -1,12 +1,6 @@
# Ignore header name
ignore define _CEC_UAPI_H
# Rename some symbols, to avoid namespace conflicts
replace struct cec_event_state_change cec-event-state-change_s
replace struct cec_event_lost_msgs cec-event-lost-msgs_s
replace enum cec_mode_initiator cec-mode-initiator_e
replace enum cec_mode_follower cec-mode-follower_e
# define macros to ignore
ignore define CEC_MAX_MSG_SIZE

10
Documentation/media/conf.py Normal file
View File

@ -0,0 +1,10 @@
# -*- coding: utf-8; mode: python -*-
project = 'Linux Media Subsystem Documentation'
tags.add("subproject")
latex_documents = [
('index', 'media.tex', 'Linux Media Subsystem Documentation',
'The kernel development community', 'manual'),
]

109
Documentation/media/conf_nitpick.py Normal file
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@ -0,0 +1,109 @@
# -*- coding: utf-8; mode: python -*-
project = 'Linux Media Subsystem Documentation'
# It is possible to run Sphinx in nickpick mode with:
nitpicky = True
# within nit-picking build, do not refer to any intersphinx object
intersphinx_mapping = {}
# In nickpick mode, it will complain about lots of missing references that
#
# 1) are just typedefs like: bool, __u32, etc;
# 2) It will complain for things like: enum, NULL;
# 3) It will complain for symbols that should be on different
# books (but currently aren't ported to ReST)
#
# The list below has a list of such symbols to be ignored in nitpick mode
#
nitpick_ignore = [
("c:func", "clock_gettime"),
("c:func", "close"),
("c:func", "container_of"),
("c:func", "copy_from_user"),
("c:func", "copy_to_user"),
("c:func", "determine_valid_ioctls"),
("c:func", "ERR_PTR"),
("c:func", "i2c_new_device"),
("c:func", "ioctl"),
("c:func", "IS_ERR"),
("c:func", "KERNEL_VERSION"),
("c:func", "mmap"),
("c:func", "open"),
("c:func", "pci_name"),
("c:func", "poll"),
("c:func", "PTR_ERR"),
("c:func", "read"),
("c:func", "release"),
("c:func", "set"),
("c:func", "struct fd_set"),
("c:func", "struct pollfd"),
("c:func", "usb_make_path"),
("c:func", "wait_finish"),
("c:func", "wait_prepare"),
("c:func", "write"),
("c:type", "atomic_t"),
("c:type", "bool"),
("c:type", "boolean"),
("c:type", "buf_queue"),
("c:type", "device"),
("c:type", "device_driver"),
("c:type", "device_node"),
("c:type", "enum"),
("c:type", "fd"),
("c:type", "fd_set"),
("c:type", "file"),
("c:type", "i2c_adapter"),
("c:type", "i2c_board_info"),
("c:type", "i2c_client"),
("c:type", "int16_t"),
("c:type", "ktime_t"),
("c:type", "led_classdev_flash"),
("c:type", "list_head"),
("c:type", "lock_class_key"),
("c:type", "module"),
("c:type", "mutex"),
("c:type", "NULL"),
("c:type", "off_t"),
("c:type", "pci_dev"),
("c:type", "pdvbdev"),
("c:type", "poll_table"),
("c:type", "platform_device"),
("c:type", "pollfd"),
("c:type", "poll_table_struct"),
("c:type", "s32"),
("c:type", "s64"),
("c:type", "sd"),
("c:type", "size_t"),
("c:type", "spi_board_info"),
("c:type", "spi_device"),
("c:type", "spi_master"),
("c:type", "ssize_t"),
("c:type", "fb_fix_screeninfo"),
("c:type", "pollfd"),
("c:type", "timeval"),
("c:type", "video_capability"),
("c:type", "timeval"),
("c:type", "__u16"),
("c:type", "u16"),
("c:type", "__u32"),
("c:type", "u32"),
("c:type", "__u64"),
("c:type", "u64"),
("c:type", "u8"),
("c:type", "uint16_t"),
("c:type", "uint32_t"),
("c:type", "union"),
("c:type", "__user"),
("c:type", "usb_device"),
("c:type", "usb_interface"),
("c:type", "v4l2_std_id"),
("c:type", "video_system_t"),
("c:type", "vm_area_struct"),
# Opaque structures
("c:type", "v4l2_m2m_dev"),
]

85
Documentation/media/dmx.h.rst.exceptions
View File

@ -4,29 +4,29 @@ ignore define _UAPI_DVBDMX_H_
# Ignore limit constants
ignore define DMX_FILTER_SIZE
# dmx-pes-type-t enum symbols
replace enum dmx_ts_pes dmx-pes-type-t
replace symbol DMX_PES_AUDIO0 dmx-pes-type-t
replace symbol DMX_PES_VIDEO0 dmx-pes-type-t
replace symbol DMX_PES_TELETEXT0 dmx-pes-type-t
replace symbol DMX_PES_SUBTITLE0 dmx-pes-type-t
replace symbol DMX_PES_PCR0 dmx-pes-type-t
replace symbol DMX_PES_AUDIO1 dmx-pes-type-t
replace symbol DMX_PES_VIDEO1 dmx-pes-type-t
replace symbol DMX_PES_TELETEXT1 dmx-pes-type-t
replace symbol DMX_PES_SUBTITLE1 dmx-pes-type-t
replace symbol DMX_PES_PCR1 dmx-pes-type-t
replace symbol DMX_PES_AUDIO2 dmx-pes-type-t
replace symbol DMX_PES_VIDEO2 dmx-pes-type-t
replace symbol DMX_PES_TELETEXT2 dmx-pes-type-t
replace symbol DMX_PES_SUBTITLE2 dmx-pes-type-t
replace symbol DMX_PES_PCR2 dmx-pes-type-t
replace symbol DMX_PES_AUDIO3 dmx-pes-type-t
replace symbol DMX_PES_VIDEO3 dmx-pes-type-t
replace symbol DMX_PES_TELETEXT3 dmx-pes-type-t
replace symbol DMX_PES_SUBTITLE3 dmx-pes-type-t
replace symbol DMX_PES_PCR3 dmx-pes-type-t
replace symbol DMX_PES_OTHER dmx-pes-type-t
# dmx_pes_type_t enum symbols
replace enum dmx_ts_pes :c:type:`dmx_pes_type`
replace symbol DMX_PES_AUDIO0 :c:type:`dmx_pes_type`
replace symbol DMX_PES_VIDEO0 :c:type:`dmx_pes_type`
replace symbol DMX_PES_TELETEXT0 :c:type:`dmx_pes_type`
replace symbol DMX_PES_SUBTITLE0 :c:type:`dmx_pes_type`
replace symbol DMX_PES_PCR0 :c:type:`dmx_pes_type`
replace symbol DMX_PES_AUDIO1 :c:type:`dmx_pes_type`
replace symbol DMX_PES_VIDEO1 :c:type:`dmx_pes_type`
replace symbol DMX_PES_TELETEXT1 :c:type:`dmx_pes_type`
replace symbol DMX_PES_SUBTITLE1 :c:type:`dmx_pes_type`
replace symbol DMX_PES_PCR1 :c:type:`dmx_pes_type`
replace symbol DMX_PES_AUDIO2 :c:type:`dmx_pes_type`
replace symbol DMX_PES_VIDEO2 :c:type:`dmx_pes_type`
replace symbol DMX_PES_TELETEXT2 :c:type:`dmx_pes_type`
replace symbol DMX_PES_SUBTITLE2 :c:type:`dmx_pes_type`
replace symbol DMX_PES_PCR2 :c:type:`dmx_pes_type`
replace symbol DMX_PES_AUDIO3 :c:type:`dmx_pes_type`
replace symbol DMX_PES_VIDEO3 :c:type:`dmx_pes_type`
replace symbol DMX_PES_TELETEXT3 :c:type:`dmx_pes_type`
replace symbol DMX_PES_SUBTITLE3 :c:type:`dmx_pes_type`
replace symbol DMX_PES_PCR3 :c:type:`dmx_pes_type`
replace symbol DMX_PES_OTHER :c:type:`dmx_pes_type`
# Ignore obsolete symbols
ignore define DMX_PES_AUDIO
@ -36,28 +36,31 @@ ignore define DMX_PES_SUBTITLE
ignore define DMX_PES_PCR
# dmx_input_t symbols
replace enum dmx_input dmx-input-t
replace symbol DMX_IN_FRONTEND dmx-input-t
replace symbol DMX_IN_DVR dmx-input-t
replace enum dmx_input :c:type:`dmx_input`
replace symbol DMX_IN_FRONTEND :c:type:`dmx_input`
replace symbol DMX_IN_DVR :c:type:`dmx_input`
# dmx_source_t symbols
replace enum dmx_source dmx-source-t
replace symbol DMX_SOURCE_FRONT0 dmx-source-t
replace symbol DMX_SOURCE_FRONT1 dmx-source-t
replace symbol DMX_SOURCE_FRONT2 dmx-source-t
replace symbol DMX_SOURCE_FRONT3 dmx-source-t
replace symbol DMX_SOURCE_DVR0 dmx-source-t
replace symbol DMX_SOURCE_DVR1 dmx-source-t
replace symbol DMX_SOURCE_DVR2 dmx-source-t
replace symbol DMX_SOURCE_DVR3 dmx-source-t
replace enum dmx_source :c:type:`dmx_source`
replace symbol DMX_SOURCE_FRONT0 :c:type:`dmx_source`
replace symbol DMX_SOURCE_FRONT1 :c:type:`dmx_source`
replace symbol DMX_SOURCE_FRONT2 :c:type:`dmx_source`
replace symbol DMX_SOURCE_FRONT3 :c:type:`dmx_source`
replace symbol DMX_SOURCE_DVR0 :c:type:`dmx_source`
replace symbol DMX_SOURCE_DVR1 :c:type:`dmx_source`
replace symbol DMX_SOURCE_DVR2 :c:type:`dmx_source`
replace symbol DMX_SOURCE_DVR3 :c:type:`dmx_source`
# Flags for struct dmx_sct_filter_params
replace define DMX_CHECK_CRC dmx-sct-filter-params
replace define DMX_ONESHOT dmx-sct-filter-params
replace define DMX_IMMEDIATE_START dmx-sct-filter-params
replace define DMX_KERNEL_CLIENT dmx-sct-filter-params
replace define DMX_CHECK_CRC :c:type:`dmx_sct_filter_params`
replace define DMX_ONESHOT :c:type:`dmx_sct_filter_params`
replace define DMX_IMMEDIATE_START :c:type:`dmx_sct_filter_params`
replace define DMX_KERNEL_CLIENT :c:type:`dmx_sct_filter_params`
# some typedefs should point to struct/enums
replace typedef dmx_caps_t dmx-caps
replace typedef dmx_filter_t dmx-filter
replace typedef dmx_caps_t :c:type:`dmx_caps`
replace typedef dmx_filter_t :c:type:`dmx_filter`
replace typedef dmx_pes_type_t :c:type:`dmx_pes_type`
replace typedef dmx_input_t :c:type:`dmx_input`
replace typedef dmx_source_t :c:type:`dmx_source`

8
Documentation/media/frontend.h.rst.exceptions
View File

@ -26,22 +26,22 @@ ignore define MAX_DTV_STATS
ignore define DTV_IOCTL_MAX_MSGS
# Stats enum is documented altogether
replace enum fecap_scale_params frontend-stat-properties
replace enum fecap_scale_params :ref:`frontend-stat-properties`
replace symbol FE_SCALE_COUNTER frontend-stat-properties
replace symbol FE_SCALE_DECIBEL frontend-stat-properties
replace symbol FE_SCALE_NOT_AVAILABLE frontend-stat-properties
replace symbol FE_SCALE_RELATIVE frontend-stat-properties
# the same reference is used for both get and set ioctls
replace ioctl FE_SET_PROPERTY FE_GET_PROPERTY
replace ioctl FE_SET_PROPERTY :c:type:`FE_GET_PROPERTY`
# Ignore struct used only internally at Kernel
ignore struct dtv_cmds_h
# Typedefs that use the enum reference
replace typedef fe_sec_voltage_t fe-sec-voltage
replace typedef fe_sec_voltage_t :c:type:`fe_sec_voltage`
# Replaces for flag constants
replace define FE_TUNE_MODE_ONESHOT fe_set_frontend_tune_mode
replace define FE_TUNE_MODE_ONESHOT :c:func:`FE_SET_FRONTEND_TUNE_MODE`
replace define LNA_AUTO dtv-lna
replace define NO_STREAM_ID_FILTER dtv-stream-id

24
Documentation/media/index.rst Normal file
View File

@ -0,0 +1,24 @@
Linux Media Subsystem Documentation
===================================
.. Sphinx 1.4.x has a definition for DUrole that doesn't work on alltt blocks
.. raw:: latex
\renewcommand*{\DUrole}[2]{ #2 }
Contents:
.. toctree::
:maxdepth: 2
media_uapi
media_kapi
dvb-drivers/index
v4l-drivers/index
.. only:: subproject
Indices
=======
* :ref:`genindex`

2
Documentation/media/intro.rst
View File

@ -30,7 +30,7 @@ divided into five parts.
called as DVB API, in fact it covers several different video standards
including DVB-T/T2, DVB-S/S2, DVB-C, ATSC, ISDB-T, ISDB-S, DTMB, etc. The
complete list of supported standards can be found at
:ref:`fe-delivery-system-t`.
:c:type:`fe_delivery_system`.
3. The :ref:`third part <remote_controllers>` covers the Remote Controller API.

123
Documentation/cec.txt → Documentation/media/kapi/cec-core.rst
View File

@ -36,39 +36,50 @@ CEC Adapter
The struct cec_adapter represents the CEC adapter hardware. It is created by
calling cec_allocate_adapter() and deleted by calling cec_delete_adapter():
struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
.. c:function::
struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops,
void *priv, const char *name, u32 caps, u8 available_las,
struct device *parent);
void cec_delete_adapter(struct cec_adapter *adap);
.. c:function::
void cec_delete_adapter(struct cec_adapter *adap);
To create an adapter you need to pass the following information:
ops: adapter operations which are called by the CEC framework and that you
have to implement.
ops:
adapter operations which are called by the CEC framework and that you
have to implement.
priv: will be stored in adap->priv and can be used by the adapter ops.
priv:
will be stored in adap->priv and can be used by the adapter ops.
name: the name of the CEC adapter. Note: this name will be copied.
name:
the name of the CEC adapter. Note: this name will be copied.
caps: capabilities of the CEC adapter. These capabilities determine the
caps:
capabilities of the CEC adapter. These capabilities determine the
capabilities of the hardware and which parts are to be handled
by userspace and which parts are handled by kernelspace. The
capabilities are returned by CEC_ADAP_G_CAPS.
available_las: the number of simultaneous logical addresses that this
available_las:
the number of simultaneous logical addresses that this
adapter can handle. Must be 1 <= available_las <= CEC_MAX_LOG_ADDRS.
parent: the parent device.
parent:
the parent device.
To register the /dev/cecX device node and the remote control device (if
CEC_CAP_RC is set) you call:
int cec_register_adapter(struct cec_adapter *adap);
.. c:function::
int cec_register_adapter(struct cec_adapter \*adap);
To unregister the devices call:
void cec_unregister_adapter(struct cec_adapter *adap);
.. c:function::
void cec_unregister_adapter(struct cec_adapter \*adap);
Note: if cec_register_adapter() fails, then call cec_delete_adapter() to
clean up. But if cec_register_adapter() succeeded, then only call
@ -83,18 +94,23 @@ Implementing the Low-Level CEC Adapter
The following low-level adapter operations have to be implemented in
your driver:
struct cec_adap_ops {
.. c:type:: struct cec_adap_ops
.. code-block:: none
struct cec_adap_ops
{
/* Low-level callbacks */
int (*adap_enable)(struct cec_adapter *adap, bool enable);
int (*adap_monitor_all_enable)(struct cec_adapter *adap, bool enable);
int (*adap_log_addr)(struct cec_adapter *adap, u8 logical_addr);
int (*adap_transmit)(struct cec_adapter *adap, u8 attempts,
u32 signal_free_time, struct cec_msg *msg);
void (*adap_log_status)(struct cec_adapter *adap);
void (\*adap_log_status)(struct cec_adapter *adap);
/* High-level callbacks */
...
};
};
The three low-level ops deal with various aspects of controlling the CEC adapter
hardware:
@ -102,6 +118,7 @@ hardware:
To enable/disable the hardware:
.. c:function::
int (*adap_enable)(struct cec_adapter *adap, bool enable);
This callback enables or disables the CEC hardware. Enabling the CEC hardware
@ -115,6 +132,7 @@ Note that adap_enable must return 0 if enable is false.
To enable/disable the 'monitor all' mode:
.. c:function::
int (*adap_monitor_all_enable)(struct cec_adapter *adap, bool enable);
If enabled, then the adapter should be put in a mode to also monitor messages
@ -127,6 +145,7 @@ Note that adap_monitor_all_enable must return 0 if enable is false.
To program a new logical address:
.. c:function::
int (*adap_log_addr)(struct cec_adapter *adap, u8 logical_addr);
If logical_addr == CEC_LOG_ADDR_INVALID then all programmed logical addresses
@ -140,6 +159,7 @@ Note that adap_log_addr must return 0 if logical_addr is CEC_LOG_ADDR_INVALID.
To transmit a new message:
.. c:function::
int (*adap_transmit)(struct cec_adapter *adap, u8 attempts,
u32 signal_free_time, struct cec_msg *msg);
@ -158,6 +178,7 @@ microseconds (one data bit period is 2.4 ms).
To log the current CEC hardware status:
.. c:function::
void (*adap_status)(struct cec_adapter *adap, struct seq_file *file);
This optional callback can be used to show the status of the CEC hardware.
@ -169,29 +190,41 @@ driven) by calling into the framework in the following situations:
When a transmit finished (successfully or otherwise):
void cec_transmit_done(struct cec_adapter *adap, u8 status, u8 arb_lost_cnt,
.. c:function::
void cec_transmit_done(struct cec_adapter *adap, u8 status, u8 arb_lost_cnt,
u8 nack_cnt, u8 low_drive_cnt, u8 error_cnt);
The status can be one of:
CEC_TX_STATUS_OK: the transmit was successful.
CEC_TX_STATUS_ARB_LOST: arbitration was lost: another CEC initiator
took control of the CEC line and you lost the arbitration.
CEC_TX_STATUS_NACK: the message was nacked (for a directed message) or
acked (for a broadcast message). A retransmission is needed.
CEC_TX_STATUS_LOW_DRIVE: low drive was detected on the CEC bus. This
indicates that a follower detected an error on the bus and requested a
retransmission.
CEC_TX_STATUS_ERROR: some unspecified error occurred: this can be one of
the previous two if the hardware cannot differentiate or something else
entirely.
CEC_TX_STATUS_MAX_RETRIES: could not transmit the message after
trying multiple times. Should only be set by the driver if it has hardware
support for retrying messages. If set, then the framework assumes that it
doesn't have to make another attempt to transmit the message since the
hardware did that already.
CEC_TX_STATUS_OK:
the transmit was successful.
The *_cnt arguments are the number of error conditions that were seen.
CEC_TX_STATUS_ARB_LOST:
arbitration was lost: another CEC initiator
took control of the CEC line and you lost the arbitration.
CEC_TX_STATUS_NACK:
the message was nacked (for a directed message) or
acked (for a broadcast message). A retransmission is needed.
CEC_TX_STATUS_LOW_DRIVE:
low drive was detected on the CEC bus. This indicates that
a follower detected an error on the bus and requested a
retransmission.
CEC_TX_STATUS_ERROR:
some unspecified error occurred: this can be one of
the previous two if the hardware cannot differentiate or something
else entirely.
CEC_TX_STATUS_MAX_RETRIES:
could not transmit the message after trying multiple times.
Should only be set by the driver if it has hardware support for
retrying messages. If set, then the framework assumes that it
doesn't have to make another attempt to transmit the message
since the hardware did that already.
The \*_cnt arguments are the number of error conditions that were seen.
This may be 0 if no information is available. Drivers that do not support
hardware retry can just set the counter corresponding to the transmit error
to 1, if the hardware does support retry then either set these counters to
@ -200,7 +233,8 @@ times, or fill in the correct values as reported by the hardware.
When a CEC message was received:
void cec_received_msg(struct cec_adapter *adap, struct cec_msg *msg);
.. c:function::
void cec_received_msg(struct cec_adapter *adap, struct cec_msg *msg);
Speaks for itself.
@ -210,17 +244,20 @@ Implementing the High-Level CEC Adapter
The low-level operations drive the hardware, the high-level operations are
CEC protocol driven. The following high-level callbacks are available:
struct cec_adap_ops {
/* Low-level callbacks */
.. code-block:: none
struct cec_adap_ops {
/\* Low-level callbacks \*/
...
/* High-level CEC message callback */
int (*received)(struct cec_adapter *adap, struct cec_msg *msg);
};
/\* High-level CEC message callback \*/
int (\*received)(struct cec_adapter \*adap, struct cec_msg \*msg);
};
The received() callback allows the driver to optionally handle a newly
received CEC message
.. c:function::
int (*received)(struct cec_adapter *adap, struct cec_msg *msg);
If the driver wants to process a CEC message, then it can implement this
@ -234,13 +271,16 @@ CEC framework functions
CEC Adapter drivers can call the following CEC framework functions:
int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg,
.. c:function::
int cec_transmit_msg(struct cec_adapter *adap, struct cec_msg *msg,
bool block);
Transmit a CEC message. If block is true, then wait until the message has been
transmitted, otherwise just queue it and return.
void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr, bool block);
.. c:function::
void cec_s_phys_addr(struct cec_adapter *adap, u16 phys_addr,
bool block);
Change the physical address. This function will set adap->phys_addr and
send an event if it has changed. If cec_s_log_addrs() has been called and
@ -254,7 +294,8 @@ then the CEC adapter will be disabled. If you change a valid physical address
to another valid physical address, then this function will first set the
address to CEC_PHYS_ADDR_INVALID before enabling the new physical address.
int cec_s_log_addrs(struct cec_adapter *adap,
.. c:function::
int cec_s_log_addrs(struct cec_adapter *adap,
struct cec_log_addrs *log_addrs, bool block);
Claim the CEC logical addresses. Should never be called if CEC_CAP_LOG_ADDRS

40
Documentation/media/kapi/dtv-core.rst
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@ -6,8 +6,6 @@ Digital TV Common functions
.. kernel-doc:: drivers/media/dvb-core/dvb_math.h
.. kernel-doc:: drivers/media/dvb-core/dvb_ringbuffer.h
.. kernel-doc:: drivers/media/dvb-core/dvbdev.h
@ -18,6 +16,42 @@ Digital TV Common functions
.. kernel-doc:: drivers/media/dvb-core/dvbdev.h
:export: drivers/media/dvb-core/dvbdev.c
Digital TV Ring buffer
----------------------
Those routines implement ring buffers used to handle digital TV data and
copy it from/to userspace.
.. note::
1) For performance reasons read and write routines don't check buffer sizes
and/or number of bytes free/available. This has to be done before these
routines are called. For example:
.. code-block:: c
/* write @buflen: bytes */
free = dvb_ringbuffer_free(rbuf);
if (free >= buflen)
count = dvb_ringbuffer_write(rbuf, buffer, buflen);
else
/* do something */
/* read min. 1000, max. @bufsize: bytes */
avail = dvb_ringbuffer_avail(rbuf);
if (avail >= 1000)
count = dvb_ringbuffer_read(rbuf, buffer, min(avail, bufsize));
else
/* do something */
2) If there is exactly one reader and one writer, there is no need
to lock read or write operations.
Two or more readers must be locked against each other.
Flushing the buffer counts as a read operation.
Resetting the buffer counts as a read and write operation.
Two or more writers must be locked against each other.
.. kernel-doc:: drivers/media/dvb-core/dvb_ringbuffer.h
Digital TV Frontend kABI
@ -121,7 +155,7 @@ triggered by a hardware interrupt, it is recommended to use the Linux
bottom half mechanism or start a tasklet instead of making the callback
function call directly from a hardware interrupt.
This mechanism is implemented by :c:func:`dmx_ts_cb()` and :cpp:func:`dmx_section_cb()`
This mechanism is implemented by :c:func:`dmx_ts_cb()` and :c:func:`dmx_section_cb()`
callbacks.
.. kernel-doc:: drivers/media/dvb-core/demux.h

25
Documentation/media/kapi/mc-core.rst
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@ -34,7 +34,7 @@ pad to a sink pad.
Media device
^^^^^^^^^^^^
A media device is represented by a :c:type:`struct media_device <media_device>`
A media device is represented by a struct :c:type:`media_device`
instance, defined in ``include/media/media-device.h``.
Allocation of the structure is handled by the media device driver, usually by
embedding the :c:type:`media_device` instance in a larger driver-specific
@ -47,7 +47,7 @@ and unregistered by calling :c:func:`media_device_unregister()`.
Entities
^^^^^^^^
Entities are represented by a :c:type:`struct media_entity <media_entity>`
Entities are represented by a struct :c:type:`media_entity`
instance, defined in ``include/media/media-entity.h``. The structure is usually
embedded into a higher-level structure, such as
:c:type:`v4l2_subdev` or :c:type:`video_device`
@ -65,10 +65,10 @@ Interfaces
^^^^^^^^^^
Interfaces are represented by a
:c:type:`struct media_interface <media_interface>` instance, defined in
struct :c:type:`media_interface` instance, defined in
``include/media/media-entity.h``. Currently, only one type of interface is
defined: a device node. Such interfaces are represented by a
:c:type:`struct media_intf_devnode <media_intf_devnode>`.
struct :c:type:`media_intf_devnode`.
Drivers initialize and create device node interfaces by calling
:c:func:`media_devnode_create()`
@ -77,7 +77,7 @@ and remove them by calling:
Pads
^^^^
Pads are represented by a :c:type:`struct media_pad <media_pad>` instance,
Pads are represented by a struct :c:type:`media_pad` instance,
defined in ``include/media/media-entity.h``. Each entity stores its pads in
a pads array managed by the entity driver. Drivers usually embed the array in
a driver-specific structure.
@ -85,8 +85,9 @@ a driver-specific structure.
Pads are identified by their entity and their 0-based index in the pads
array.
Both information are stored in the :c:type:`struct media_pad`, making the
:c:type:`media_pad` pointer the canonical way to store and pass link references.
Both information are stored in the struct :c:type:`media_pad`,
making the struct :c:type:`media_pad` pointer the canonical way
to store and pass link references.
Pads have flags that describe the pad capabilities and state.
@ -101,7 +102,7 @@ Pads have flags that describe the pad capabilities and state.
Links
^^^^^
Links are represented by a :c:type:`struct media_link <media_link>` instance,
Links are represented by a struct :c:type:`media_link` instance,
defined in ``include/media/media-entity.h``. There are two types of links:
**1. pad to pad links**:
@ -184,7 +185,7 @@ Use count and power handling
Due to the wide differences between drivers regarding power management
needs, the media controller does not implement power management. However,
the :c:type:`struct media_entity <media_entity>` includes a ``use_count``
the struct :c:type:`media_entity` includes a ``use_count``
field that media drivers
can use to track the number of users of every entity for power management
needs.
@ -210,11 +211,11 @@ prevent link states from being modified during streaming by calling
The function will mark all entities connected to the given entity through
enabled links, either directly or indirectly, as streaming.
The :c:type:`struct media_pipeline <media_pipeline>` instance pointed to by
The struct :c:type:`media_pipeline` instance pointed to by
the pipe argument will be stored in every entity in the pipeline.
Drivers should embed the :c:type:`struct media_pipeline <media_pipeline>`
Drivers should embed the struct :c:type:`media_pipeline`
in higher-level pipeline structures and can then access the
pipeline through the :c:type:`struct media_entity <media_entity>`
pipeline through the struct :c:type:`media_entity`
pipe field.
Calls to :c:func:`media_entity_pipeline_start()` can be nested.

10
Documentation/media/kapi/v4l2-dev.rst
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@ -56,7 +56,7 @@ You should also set these fields of :c:type:`video_device`:
:c:type:`video_device`->vfl_dir fields are used to disable ops that do not
match the type/dir combination. E.g. VBI ops are disabled for non-VBI nodes,
and output ops are disabled for a capture device. This makes it possible to
provide just one :c:type:`v4l2_ioctl_ops struct` for both vbi and
provide just one :c:type:`v4l2_ioctl_ops` struct for both vbi and
video nodes.
- :c:type:`video_device`->lock: leave to ``NULL`` if you want to do all the
@ -166,14 +166,14 @@ something.
In the case of :ref:`videobuf2 <vb2_framework>` you will need to implement the
``wait_prepare()`` and ``wait_finish()`` callbacks to unlock/lock if applicable.
If you use the ``queue->lock`` pointer, then you can use the helper functions
:c:func:`vb2_ops_wait_prepare` and :cpp:func:`vb2_ops_wait_finish`.
:c:func:`vb2_ops_wait_prepare` and :c:func:`vb2_ops_wait_finish`.
The implementation of a hotplug disconnect should also take the lock from
:c:type:`video_device` before calling v4l2_device_disconnect. If you are also
using :c:type:`video_device`->queue->lock, then you have to first lock
:c:type:`video_device`->queue->lock followed by :c:type:`video_device`->lock.
That way you can be sure no ioctl is running when you call
:c:type:`v4l2_device_disconnect`.
:c:func:`v4l2_device_disconnect`.
Video device registration
-------------------------
@ -200,6 +200,7 @@ types exist:
- ``VFL_TYPE_VBI``: ``/dev/vbiX`` for vertical blank data (i.e. closed captions, teletext)
- ``VFL_TYPE_RADIO``: ``/dev/radioX`` for radio tuners
- ``VFL_TYPE_SDR``: ``/dev/swradioX`` for Software Defined Radio tuners
- ``VFL_TYPE_TOUCH``: ``/dev/v4l-touchX`` for touch sensors
The last argument gives you a certain amount of control over the device
device node number used (i.e. the X in ``videoX``). Normally you will pass -1
@ -262,6 +263,7 @@ file operations.
It is a bitmask and the following bits can be set:
.. tabularcolumns:: |p{5ex}|L|
===== ================================================================
Mask Description
@ -334,7 +336,7 @@ And this function:
returns the video_device belonging to the file struct.
The :c:func:`video_devdata` function combines :cpp:func:`video_get_drvdata`
The :c:func:`video_devdata` function combines :c:func:`video_get_drvdata`
with :c:func:`video_devdata`:
:c:func:`video_drvdata <video_drvdata>`

6
Documentation/media/kapi/v4l2-event.rst
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@ -40,7 +40,7 @@ A good example of these ``replace``/``merge`` callbacks is in v4l2-event.c:
In order to queue events to video device, drivers should call:
:c:func:`v4l2_event_queue <v4l2_event_queue>`
(:c:type:`vdev <video_device>`, :ref:`ev <v4l2-event>`)
(:c:type:`vdev <video_device>`, :c:type:`ev <v4l2_event>`)
The driver's only responsibility is to fill in the type and the data fields.
The other fields will be filled in by V4L2.
@ -51,7 +51,7 @@ Event subscription
Subscribing to an event is via:
:c:func:`v4l2_event_subscribe <v4l2_event_subscribe>`
(:c:type:`fh <v4l2_fh>`, :ref:`sub <v4l2-event-subscription>` ,
(:c:type:`fh <v4l2_fh>`, :c:type:`sub <v4l2_event_subscription>` ,
elems, :c:type:`ops <v4l2_subscribed_event_ops>`)
@ -86,7 +86,7 @@ Unsubscribing an event
Unsubscribing to an event is via:
:c:func:`v4l2_event_unsubscribe <v4l2_event_unsubscribe>`
(:c:type:`fh <v4l2_fh>`, :ref:`sub <v4l2-event-subscription>`)
(:c:type:`fh <v4l2_fh>`, :c:type:`sub <v4l2_event_subscription>`)
This function is used to implement :c:type:`video_device`->
:c:type:`ioctl_ops <v4l2_ioctl_ops>`-> ``vidioc_unsubscribe_event``.

4
Documentation/media/kapi/v4l2-fh.rst
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@ -21,8 +21,8 @@ function by the driver.
In many cases the struct :c:type:`v4l2_fh` will be embedded in a larger
structure. In that case you should call:
#) :c:func:`v4l2_fh_init` and :cpp:func:`v4l2_fh_add` in ``open()``
#) :c:func:`v4l2_fh_del` and :cpp:func:`v4l2_fh_exit` in ``release()``
#) :c:func:`v4l2_fh_init` and :c:func:`v4l2_fh_add` in ``open()``
#) :c:func:`v4l2_fh_del` and :c:func:`v4l2_fh_exit` in ``release()``
Drivers can extract their own file handle structure by using the container_of
macro.

23
Documentation/media/kapi/v4l2-subdev.rst
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@ -27,7 +27,7 @@ methods.
Bridges might also need to store per-subdev private data, such as a pointer to
bridge-specific per-subdev private data. The :c:type:`v4l2_subdev` structure
provides host private data for that purpose that can be accessed with
:c:func:`v4l2_get_subdev_hostdata` and :cpp:func:`v4l2_set_subdev_hostdata`.
:c:func:`v4l2_get_subdev_hostdata` and :c:func:`v4l2_set_subdev_hostdata`.
From the bridge driver perspective, you load the sub-device module and somehow
obtain the :c:type:`v4l2_subdev` pointer. For i2c devices this is easy: you call
@ -412,19 +412,7 @@ later date. It differs between i2c drivers and as such can be confusing.
To see which chip variants are supported you can look in the i2c driver code
for the i2c_device_id table. This lists all the possibilities.
There are two more helper functions:
:c:func:`v4l2_i2c_new_subdev_cfg`: this function adds new irq and
platform_data arguments and has both 'addr' and 'probed_addrs' arguments:
if addr is not 0 then that will be used (non-probing variant), otherwise the
probed_addrs are probed.
For example: this will probe for address 0x10:
.. code-block:: c
struct v4l2_subdev *sd = v4l2_i2c_new_subdev_cfg(v4l2_dev, adapter,
"module_foo", "chipid", 0, NULL, 0, I2C_ADDRS(0x10));
There are one more helper function:
:c:func:`v4l2_i2c_new_subdev_board` uses an :c:type:`i2c_board_info` struct
which is passed to the i2c driver and replaces the irq, platform_data and addr
@ -433,9 +421,10 @@ arguments.
If the subdev supports the s_config core ops, then that op is called with
the irq and platform_data arguments after the subdev was setup.
The older :c:func:`v4l2_i2c_new_subdev` and
:c:func:`v4l2_i2c_new_probed_subdev` functions will call ``s_config`` as
well, but with irq set to 0 and platform_data set to ``NULL``.
The :c:func:`v4l2_i2c_new_subdev` function will call
:c:func:`v4l2_i2c_new_subdev_board`, internally filling a
:c:type:`i2c_board_info` structure using the ``client_type`` and the
``addr`` to fill it.
V4L2 sub-device functions and data structures
---------------------------------------------

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1
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@ -32,3 +32,4 @@ For more details see the file COPYING in the source distribution of Linux.
kapi/dtv-core
kapi/rc-core
kapi/mc-core
kapi/cec-core

4
Documentation/media/net.h.rst.exceptions
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@ -7,5 +7,5 @@ ignore ioctl __NET_GET_IF_OLD
ignore struct __dvb_net_if_old
# Macros used at struct dvb_net_if
replace define DVB_NET_FEEDTYPE_MPE dvb-net-if
replace define DVB_NET_FEEDTYPE_ULE dvb-net-if
replace define DVB_NET_FEEDTYPE_MPE :c:type:`dvb_net_if`
replace define DVB_NET_FEEDTYPE_ULE :c:type:`dvb_net_if`

9
Documentation/media/uapi/cec/cec-func-close.rst
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@ -20,19 +20,22 @@ Synopsis
#include <unistd.h>
.. cpp:function:: int close( int fd )
.. c:function:: int close( int fd )
:name: cec-close
Arguments
=========
``fd``
File descriptor returned by :ref:`open() <func-open>`.
File descriptor returned by :c:func:`open() <cec-open>`.
Description
===========
.. note:: This documents the proposed CEC API. This API is not yet finalized
.. note::
This documents the proposed CEC API. This API is not yet finalized
and is currently only available as a staging kernel module.
Closes the cec device. Resources associated with the file descriptor are

11
Documentation/media/uapi/cec/cec-func-ioctl.rst
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@ -19,17 +19,18 @@ Synopsis
#include <sys/ioctl.h>
.. cpp:function:: int ioctl( int fd, int request, void *argp )
.. c:function:: int ioctl( int fd, int request, void *argp )
:name: cec-ioctl
Arguments
=========
``fd``
File descriptor returned by :ref:`open() <func-open>`.
File descriptor returned by :c:func:`open() <cec-open>`.
``request``
CEC ioctl request code as defined in the cec.h header file, for
example :ref:`CEC_ADAP_G_CAPS`.
example :c:func:`CEC_ADAP_G_CAPS`.
``argp``
Pointer to a request-specific structure.
@ -38,7 +39,9 @@ Arguments
Description
===========
.. note:: This documents the proposed CEC API. This API is not yet finalized
.. note::
This documents the proposed CEC API. This API is not yet finalized
and is currently only available as a staging kernel module.
The :c:func:`ioctl()` function manipulates cec device parameters. The

9
Documentation/media/uapi/cec/cec-func-open.rst
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@ -19,7 +19,8 @@ Synopsis
#include <fcntl.h>
.. cpp:function:: int open( const char *device_name, int flags )
.. c:function:: int open( const char *device_name, int flags )
:name: cec-open
Arguments
@ -32,7 +33,7 @@ Arguments
Open flags. Access mode must be ``O_RDWR``.
When the ``O_NONBLOCK`` flag is given, the
:ref:`CEC_RECEIVE <CEC_RECEIVE>` and :ref:`CEC_DQEVENT <CEC_DQEVENT>` ioctls
:ref:`CEC_RECEIVE <CEC_RECEIVE>` and :c:func:`CEC_DQEVENT` ioctls
will return the ``EAGAIN`` error code when no message or event is available, and
ioctls :ref:`CEC_TRANSMIT <CEC_TRANSMIT>`,
:ref:`CEC_ADAP_S_PHYS_ADDR <CEC_ADAP_S_PHYS_ADDR>` and
@ -45,7 +46,9 @@ Arguments
Description
===========
.. note:: This documents the proposed CEC API. This API is not yet finalized
.. note::
This documents the proposed CEC API. This API is not yet finalized
and is currently only available as a staging kernel module.
To open a cec device applications call :c:func:`open()` with the

18
Documentation/media/uapi/cec/cec-func-poll.rst
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@ -20,16 +20,28 @@ Synopsis
#include <sys/poll.h>
.. cpp:function:: int poll( struct pollfd *ufds, unsigned int nfds, int timeout )
.. c:function:: int poll( struct pollfd *ufds, unsigned int nfds, int timeout )
:name: cec-poll
Arguments
=========
``ufds``
List of FD events to be watched
``nfds``
Number of FD efents at the \*ufds array
``timeout``
Timeout to wait for events
Description
===========
.. note:: This documents the proposed CEC API. This API is not yet finalized
.. note::
This documents the proposed CEC API. This API is not yet finalized
and is currently only available as a staging kernel module.
With the :c:func:`poll()` function applications can wait for CEC
@ -37,7 +49,7 @@ events.
On success :c:func:`poll()` returns the number of file descriptors
that have been selected (that is, file descriptors for which the
``revents`` field of the respective :c:type:`struct pollfd` structure
``revents`` field of the respective struct :c:type:`pollfd`
is non-zero). CEC devices set the ``POLLIN`` and ``POLLRDNORM`` flags in
the ``revents`` field if there are messages in the receive queue. If the
transmit queue has room for new messages, the ``POLLOUT`` and

4
Documentation/media/uapi/cec/cec-intro.rst
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@ -3,7 +3,9 @@
Introduction
============
.. note:: This documents the proposed CEC API. This API is not yet finalized
.. note::
This documents the proposed CEC API. This API is not yet finalized
and is currently only available as a staging kernel module.
HDMI connectors provide a single pin for use by the Consumer Electronics

16
Documentation/media/uapi/cec/cec-ioc-adap-g-caps.rst
View File

@ -14,7 +14,8 @@ CEC_ADAP_G_CAPS - Query device capabilities
Synopsis
========
.. cpp:function:: int ioctl( int fd, int request, struct cec_caps *argp )
.. c:function:: int ioctl( int fd, CEC_ADAP_G_CAPS, struct cec_caps *argp )
:name: CEC_ADAP_G_CAPS
Arguments
=========
@ -22,25 +23,25 @@ Arguments
``fd``
File descriptor returned by :ref:`open() <cec-func-open>`.
``request``
CEC_ADAP_G_CAPS
``argp``
Description
===========
.. note:: This documents the proposed CEC API. This API is not yet finalized
.. note::
This documents the proposed CEC API. This API is not yet finalized
and is currently only available as a staging kernel module.
All cec devices must support :ref:`ioctl CEC_ADAP_G_CAPS <CEC_ADAP_G_CAPS>`. To query
device information, applications call the ioctl with a pointer to a
struct :ref:`cec_caps <cec-caps>`. The driver fills the structure and
struct :c:type:`cec_caps`. The driver fills the structure and
returns the information to the application. The ioctl never fails.
.. tabularcolumns:: |p{1.2cm}|p{2.5cm}|p{13.8cm}|
.. _cec-caps:
.. c:type:: cec_caps
.. flat-table:: struct cec_caps
:header-rows: 0
@ -84,6 +85,7 @@ returns the information to the application. The ioctl never fails.
macro.
.. tabularcolumns:: |p{4.4cm}|p{2.5cm}|p{10.6cm}|
.. _cec-capabilities:

31
Documentation/media/uapi/cec/cec-ioc-adap-g-log-addrs.rst
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@ -17,33 +17,35 @@ CEC_ADAP_G_LOG_ADDRS, CEC_ADAP_S_LOG_ADDRS - Get or set the logical addresses
Synopsis
========
.. cpp:function:: int ioctl( int fd, int request, struct cec_log_addrs *argp )
.. c:function:: int ioctl( int fd, CEC_ADAP_G_LOG_ADDRS, struct cec_log_addrs *argp )
:name: CEC_ADAP_G_LOG_ADDRS
.. c:function:: int ioctl( int fd, CEC_ADAP_S_LOG_ADDRS, struct cec_log_addrs *argp )
:name: CEC_ADAP_S_LOG_ADDRS
Arguments
=========
``fd``
File descriptor returned by :ref:`open() <cec-func-open>`.
``request``
CEC_ADAP_G_LOG_ADDRS, CEC_ADAP_S_LOG_ADDRS
File descriptor returned by :c:func:`open() <cec-open>`.
``argp``
Pointer to struct :c:type:`cec_log_addrs`.
Description
===========
.. note:: This documents the proposed CEC API. This API is not yet finalized
.. note::
This documents the proposed CEC API. This API is not yet finalized
and is currently only available as a staging kernel module.
To query the current CEC logical addresses, applications call
:ref:`ioctl CEC_ADAP_G_LOG_ADDRS <CEC_ADAP_G_LOG_ADDRS>` with a pointer to a
:c:type:`struct cec_log_addrs` where the driver stores the logical addresses.
struct :c:type:`cec_log_addrs` where the driver stores the logical addresses.
To set new logical addresses, applications fill in
:c:type:`struct cec_log_addrs` and call :ref:`ioctl CEC_ADAP_S_LOG_ADDRS <CEC_ADAP_S_LOG_ADDRS>`
struct :c:type:`cec_log_addrs` and call :ref:`ioctl CEC_ADAP_S_LOG_ADDRS <CEC_ADAP_S_LOG_ADDRS>`
with a pointer to this struct. The :ref:`ioctl CEC_ADAP_S_LOG_ADDRS <CEC_ADAP_S_LOG_ADDRS>`
is only available if ``CEC_CAP_LOG_ADDRS`` is set (the ``ENOTTY`` error code is
returned otherwise). The :ref:`ioctl CEC_ADAP_S_LOG_ADDRS <CEC_ADAP_S_LOG_ADDRS>`
@ -64,8 +66,11 @@ logical addresses are claimed or cleared.
Attempting to call :ref:`ioctl CEC_ADAP_S_LOG_ADDRS <CEC_ADAP_S_LOG_ADDRS>` when
logical address types are already defined will return with error ``EBUSY``.
.. c:type:: cec_log_addrs
.. _cec-log-addrs:
.. tabularcolumns:: |p{1.0cm}|p{7.5cm}|p{8.0cm}|
.. cssclass:: longtable
.. flat-table:: struct cec_log_addrs
:header-rows: 0
@ -220,6 +225,8 @@ logical address types are already defined will return with error ``EBUSY``.
fallback to the Unregistered logical address. Note that if the Unregistered
logical address was explicitly requested, then this flag has no effect.
.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
.. _cec-versions:
.. flat-table:: CEC Versions
@ -253,6 +260,7 @@ logical address types are already defined will return with error ``EBUSY``.
- CEC version according to the HDMI 2.0 standard.
.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
.. _cec-prim-dev-types:
@ -319,6 +327,7 @@ logical address types are already defined will return with error ``EBUSY``.
- Use for a video processor device.
.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
.. _cec-log-addr-types:
@ -388,6 +397,8 @@ logical address types are already defined will return with error ``EBUSY``.
.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
.. _cec-all-dev-types-flags:
.. flat-table:: CEC All Device Types Flags

17
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@ -17,24 +17,27 @@ CEC_ADAP_G_PHYS_ADDR, CEC_ADAP_S_PHYS_ADDR - Get or set the physical address
Synopsis
========
.. cpp:function:: int ioctl( int fd, int request, __u16 *argp )
.. c:function:: int ioctl( int fd, CEC_ADAP_G_PHYS_ADDR, __u16 *argp )
:name: CEC_ADAP_G_PHYS_ADDR
.. c:function:: int ioctl( int fd, CEC_ADAP_S_PHYS_ADDR, __u16 *argp )
:name: CEC_ADAP_S_PHYS_ADDR
Arguments
=========
``fd``
File descriptor returned by :ref:`open() <cec-func-open>`.
``request``
CEC_ADAP_G_PHYS_ADDR, CEC_ADAP_S_PHYS_ADDR
File descriptor returned by :c:func:`open() <cec-open>`.
``argp``
Pointer to the CEC address.
Description
===========
.. note:: This documents the proposed CEC API. This API is not yet finalized
.. note::
This documents the proposed CEC API. This API is not yet finalized
and is currently only available as a staging kernel module.
To query the current physical address applications call

38
Documentation/media/uapi/cec/cec-ioc-dqevent.rst
View File

@ -15,7 +15,8 @@ CEC_DQEVENT - Dequeue a CEC event
Synopsis
========
.. cpp:function:: int ioctl( int fd, int request, struct cec_event *argp )
.. c:function:: int ioctl( int fd, CEC_DQEVENT, struct cec_event *argp )
:name: CEC_DQEVENT
Arguments
=========
@ -23,20 +24,19 @@ Arguments
``fd``
File descriptor returned by :ref:`open() <cec-func-open>`.
``request``
CEC_DQEVENT
``argp``
Description
===========
.. note:: This documents the proposed CEC API. This API is not yet finalized
.. note::
This documents the proposed CEC API. This API is not yet finalized
and is currently only available as a staging kernel module.
CEC devices can send asynchronous events. These can be retrieved by
calling :ref:`ioctl CEC_DQEVENT <CEC_DQEVENT>`. If the file descriptor is in
calling :c:func:`CEC_DQEVENT`. If the file descriptor is in
non-blocking mode and no event is pending, then it will return -1 and
set errno to the ``EAGAIN`` error code.
@ -49,8 +49,9 @@ two :ref:`CEC_EVENT_STATE_CHANGE <CEC-EVENT-STATE-CHANGE>` events with
the same state). In that case the intermediate state changes were lost but
it is guaranteed that the state did change in between the two events.
.. tabularcolumns:: |p{1.2cm}|p{2.9cm}|p{13.4cm}|
.. _cec-event-state-change_s:
.. c:type:: cec_event_state_change
.. flat-table:: struct cec_event_state_change
:header-rows: 0
@ -79,8 +80,9 @@ it is guaranteed that the state did change in between the two events.
has the unregistered logical address. In that case all other bits are 0.
.. c:type:: cec_event_lost_msgs
.. _cec-event-lost-msgs_s:
.. tabularcolumns:: |p{1.0cm}|p{2.0cm}|p{14.5cm}|
.. flat-table:: struct cec_event_lost_msgs
:header-rows: 0
@ -105,8 +107,9 @@ it is guaranteed that the state did change in between the two events.
this is more than enough.
.. tabularcolumns:: |p{1.0cm}|p{4.2cm}|p{2.5cm}|p{8.8cm}|
.. _cec-event:
.. c:type:: cec_event
.. flat-table:: struct cec_event
:header-rows: 0
@ -120,11 +123,10 @@ it is guaranteed that the state did change in between the two events.
- ``ts``
- Timestamp of the event in ns.
The timestamp has been taken from the ``CLOCK_MONOTONIC`` clock. To access
the same clock from userspace use :c:func:`clock_gettime(2)`.
- :cspan:`1` Timestamp of the event in ns.
-
The timestamp has been taken from the ``CLOCK_MONOTONIC`` clock. To access
the same clock from userspace use :c:func:`clock_gettime`.
- .. row 2
@ -132,9 +134,7 @@ it is guaranteed that the state did change in between the two events.
- ``event``
- The CEC event type, see :ref:`cec-events`.
-
- :cspan:`1` The CEC event type, see :ref:`cec-events`.
- .. row 3
@ -142,9 +142,7 @@ it is guaranteed that the state did change in between the two events.
- ``flags``
- Event flags, see :ref:`cec-event-flags`.
-
- :cspan:`1` Event flags, see :ref:`cec-event-flags`.
- .. row 4
@ -176,6 +174,7 @@ it is guaranteed that the state did change in between the two events.
event.
.. tabularcolumns:: |p{5.6cm}|p{0.9cm}|p{11.0cm}|
.. _cec-events:
@ -205,6 +204,7 @@ it is guaranteed that the state did change in between the two events.
application didn't dequeue CEC messages fast enough.
.. tabularcolumns:: |p{6.0cm}|p{0.6cm}|p{10.9cm}|
.. _cec-event-flags:

20
Documentation/media/uapi/cec/cec-ioc-g-mode.rst
View File

@ -13,24 +13,27 @@ CEC_G_MODE, CEC_S_MODE - Get or set exclusive use of the CEC adapter
Synopsis
========
.. cpp:function:: int ioctl( int fd, int request, __u32 *argp )
.. c:function:: int ioctl( int fd, CEC_G_MODE, __u32 *argp )
:name: CEC_G_MODE
.. c:function:: int ioctl( int fd, CEC_S_MODE, __u32 *argp )
:name: CEC_S_MODE
Arguments
=========
``fd``
File descriptor returned by :ref:`open() <cec-func-open>`.
``request``
CEC_G_MODE, CEC_S_MODE
File descriptor returned by :c:func:`open() <cec-open>`.
``argp``
Pointer to CEC mode.
Description
===========
.. note:: This documents the proposed CEC API. This API is not yet finalized
.. note::
This documents the proposed CEC API. This API is not yet finalized
and is currently only available as a staging kernel module.
By default any filehandle can use :ref:`CEC_TRANSMIT`, but in order to prevent
@ -71,6 +74,7 @@ always call :ref:`ioctl CEC_TRANSMIT <CEC_TRANSMIT>`.
Available initiator modes are:
.. tabularcolumns:: |p{5.6cm}|p{0.9cm}|p{11.0cm}|
.. _cec-mode-initiator_e:
@ -114,6 +118,7 @@ Available initiator modes are:
Available follower modes are:
.. tabularcolumns:: |p{6.6cm}|p{0.9cm}|p{10.0cm}|
.. _cec-mode-follower_e:
@ -206,6 +211,7 @@ Available follower modes are:
Core message processing details:
.. tabularcolumns:: |p{6.6cm}|p{10.9cm}|
.. _cec-core-processing:

38
Documentation/media/uapi/cec/cec-ioc-receive.rst
View File

@ -16,28 +16,32 @@ CEC_RECEIVE, CEC_TRANSMIT - Receive or transmit a CEC message
Synopsis
========
.. cpp:function:: int ioctl( int fd, int request, struct cec_msg *argp )
.. c:function:: int ioctl( int fd, CEC_RECEIVE, struct cec_msg *argp )
:name: CEC_RECEIVE
.. c:function:: int ioctl( int fd, CEC_TRANSMIT, struct cec_msg *argp )
:name: CEC_TRANSMIT
Arguments
=========
``fd``
File descriptor returned by :ref:`open() <cec-func-open>`.
``request``
CEC_RECEIVE, CEC_TRANSMIT
File descriptor returned by :c:func:`open() <cec-open>`.
``argp``
Pointer to struct cec_msg.
Description
===========
.. note:: This documents the proposed CEC API. This API is not yet finalized
.. note::
This documents the proposed CEC API. This API is not yet finalized
and is currently only available as a staging kernel module.
To receive a CEC message the application has to fill in the
``timeout`` field of :c:type:`struct cec_msg` and pass it to :ref:`ioctl CEC_RECEIVE <CEC_RECEIVE>`.
``timeout`` field of struct :c:type:`cec_msg` and pass it to
:ref:`ioctl CEC_RECEIVE <CEC_RECEIVE>`.
If the file descriptor is in non-blocking mode and there are no received
messages pending, then it will return -1 and set errno to the ``EAGAIN``
error code. If the file descriptor is in blocking mode and ``timeout``
@ -51,9 +55,9 @@ A received message can be:
2. the result of an earlier non-blocking transmit (the ``sequence`` field will
be non-zero).
To send a CEC message the application has to fill in the
:c:type:`struct cec_msg` and pass it to
:ref:`ioctl CEC_TRANSMIT <CEC_TRANSMIT>`. The :ref:`ioctl CEC_TRANSMIT <CEC_TRANSMIT>` is only available if
To send a CEC message the application has to fill in the struct
:c:type:` cec_msg` and pass it to :ref:`ioctl CEC_TRANSMIT <CEC_TRANSMIT>`.
The :ref:`ioctl CEC_TRANSMIT <CEC_TRANSMIT>` is only available if
``CEC_CAP_TRANSMIT`` is set. If there is no more room in the transmit
queue, then it will return -1 and set errno to the ``EBUSY`` error code.
The transmit queue has enough room for 18 messages (about 1 second worth
@ -71,7 +75,11 @@ checked against the received messages to find the corresponding transmit
result.
.. _cec-msg:
.. tabularcolumns:: |p{1.0cm}|p{3.5cm}|p{13.0cm}|
.. c:type:: cec_msg
.. cssclass:: longtable
.. flat-table:: struct cec_msg
:header-rows: 0
@ -87,7 +95,7 @@ result.
- Timestamp in ns of when the last byte of the message was transmitted.
The timestamp has been taken from the ``CLOCK_MONOTONIC`` clock. To access
the same clock from userspace use :c:func:`clock_gettime(2)`.
the same clock from userspace use :c:func:`clock_gettime`.
- .. row 2
@ -97,7 +105,7 @@ result.
- Timestamp in ns of when the last byte of the message was received.
The timestamp has been taken from the ``CLOCK_MONOTONIC`` clock. To access
the same clock from userspace use :c:func:`clock_gettime(2)`.
the same clock from userspace use :c:func:`clock_gettime`.
- .. row 3
@ -247,6 +255,7 @@ result.
valid if the :ref:`CEC_TX_STATUS_ERROR <CEC-TX-STATUS-ERROR>` status bit is set.
.. tabularcolumns:: |p{5.6cm}|p{0.9cm}|p{11.0cm}|
.. _cec-tx-status:
@ -315,6 +324,7 @@ result.
be set to explain which failures were seen.
.. tabularcolumns:: |p{5.6cm}|p{0.9cm}|p{11.0cm}|
.. _cec-rx-status:

15
Documentation/media/uapi/dvb/audio-bilingual-channel-select.rst
View File

@ -11,11 +11,13 @@ Name
AUDIO_BILINGUAL_CHANNEL_SELECT
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: int ioctl(int fd, int request = AUDIO_BILINGUAL_CHANNEL_SELECT, audio_channel_select_t)
.. c:function:: int ioctl(int fd, AUDIO_BILINGUAL_CHANNEL_SELECT, struct *audio_channel_select)
:name: AUDIO_BILINGUAL_CHANNEL_SELECT
Arguments
@ -25,20 +27,13 @@ Arguments
:header-rows: 0
:stub-columns: 0
- .. row 1
-
- int fd
- File descriptor returned by a previous call to open().
- .. row 2
- int request
- Equals AUDIO_BILINGUAL_CHANNEL_SELECT for this command.
- .. row 3
-
- audio_channel_select_t ch

14
Documentation/media/uapi/dvb/audio-channel-select.rst
View File

@ -11,11 +11,13 @@ Name
AUDIO_CHANNEL_SELECT
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: int ioctl(int fd, int request = AUDIO_CHANNEL_SELECT, audio_channel_select_t)
.. c:function:: int ioctl(int fd, AUDIO_CHANNEL_SELECT, struct *audio_channel_select)
:name: AUDIO_CHANNEL_SELECT
Arguments
@ -26,19 +28,13 @@ Arguments
:stub-columns: 0
- .. row 1
-
- int fd
- File descriptor returned by a previous call to open().
- .. row 2
- int request
- Equals AUDIO_CHANNEL_SELECT for this command.
- .. row 3
-
- audio_channel_select_t ch

12
Documentation/media/uapi/dvb/audio-clear-buffer.rst
View File

@ -11,12 +11,13 @@ Name
AUDIO_CLEAR_BUFFER
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: int ioctl(int fd, int request = AUDIO_CLEAR_BUFFER)
.. c:function:: int ioctl(int fd, AUDIO_CLEAR_BUFFER)
:name: AUDIO_CLEAR_BUFFER
Arguments
---------
@ -32,13 +33,6 @@ Arguments
- File descriptor returned by a previous call to open().
- .. row 2
- int request
- Equals AUDIO_CLEAR_BUFFER for this command.
Description
-----------

11
Documentation/media/uapi/dvb/audio-continue.rst
View File

@ -11,11 +11,13 @@ Name
AUDIO_CONTINUE
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: int ioctl(int fd, int request = AUDIO_CONTINUE)
.. c:function:: int ioctl(int fd, AUDIO_CONTINUE)
:name: AUDIO_CONTINUE
Arguments
@ -32,13 +34,6 @@ Arguments
- File descriptor returned by a previous call to open().
- .. row 2
- int request
- Equals AUDIO_CONTINUE for this command.
Description
-----------

4
Documentation/media/uapi/dvb/audio-fclose.rst
View File

@ -11,11 +11,13 @@ Name
DVB audio close()
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: int close(int fd)
.. c:function:: int close(int fd)
:name: dvb-audio-close
Arguments

6
Documentation/media/uapi/dvb/audio-fopen.rst
View File

@ -11,11 +11,13 @@ Name
DVB audio open()
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: int open(const char *deviceName, int flags)
.. c:function:: int open(const char *deviceName, int flags)
:name: dvb-audio-open
Arguments
@ -80,6 +82,8 @@ AUDIO_GET_STATUS. All other call will return with an error code.
Return Value
------------
.. tabularcolumns:: |p{2.5cm}|p{15.0cm}|
.. flat-table::
:header-rows: 0
:stub-columns: 0

4
Documentation/media/uapi/dvb/audio-fwrite.rst
View File

@ -11,11 +11,13 @@ Name
DVB audio write()
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: size_t write(int fd, const void *buf, size_t count)
.. c:function:: size_t write(int fd, const void *buf, size_t count)
:name: dvb-audio-write
Arguments

14
Documentation/media/uapi/dvb/audio-get-capabilities.rst
View File

@ -11,11 +11,13 @@ Name
AUDIO_GET_CAPABILITIES
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: int ioctl(int fd, int request = AUDIO_GET_CAPABILITIES, unsigned int *cap)
.. c:function:: int ioctl(int fd, AUDIO_GET_CAPABILITIES, unsigned int *cap)
:name: AUDIO_GET_CAPABILITIES
Arguments
@ -26,19 +28,13 @@ Arguments
:stub-columns: 0
- .. row 1
-
- int fd
- File descriptor returned by a previous call to open().
- .. row 2
- int request
- Equals AUDIO_GET_CAPABILITIES for this command.
- .. row 3
-
- unsigned int \*cap

14
Documentation/media/uapi/dvb/audio-get-pts.rst
View File

@ -11,11 +11,13 @@ Name
AUDIO_GET_PTS
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: int ioctl(int fd, int request = AUDIO_GET_PTS, __u64 *pts)
.. c:function:: int ioctl(int fd, AUDIO_GET_PTS, __u64 *pts)
:name: AUDIO_GET_PTS
Arguments
@ -26,19 +28,13 @@ Arguments
:stub-columns: 0
- .. row 1
-
- int fd
- File descriptor returned by a previous call to open().
- .. row 2
- int request
- Equals AUDIO_GET_PTS for this command.
- .. row 3
-
- __u64 \*pts

14
Documentation/media/uapi/dvb/audio-get-status.rst
View File

@ -11,11 +11,13 @@ Name
AUDIO_GET_STATUS
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: int ioctl(int fd, int request = AUDIO_GET_STATUS, struct audio_status *status)
.. c:function:: int ioctl(int fd, AUDIO_GET_STATUS, struct audio_status *status)
:name: AUDIO_GET_STATUS
Arguments
@ -26,19 +28,13 @@ Arguments
:stub-columns: 0
- .. row 1
-
- int fd
- File descriptor returned by a previous call to open().
- .. row 2
- int request
- Equals AUDIO_GET_STATUS for this command.
- .. row 3
-
- struct audio_status \*status

11
Documentation/media/uapi/dvb/audio-pause.rst
View File

@ -11,12 +11,13 @@ Name
AUDIO_PAUSE
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: int ioctl(int fd, int request = AUDIO_PAUSE)
.. c:function:: int ioctl(int fd, AUDIO_PAUSE)
:name: AUDIO_PAUSE
Arguments
---------
@ -32,12 +33,6 @@ Arguments
- File descriptor returned by a previous call to open().
- .. row 2
- int request
- Equals AUDIO_PAUSE for this command.
Description
-----------

11
Documentation/media/uapi/dvb/audio-play.rst
View File

@ -11,11 +11,13 @@ Name
AUDIO_PLAY
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: int ioctl(int fd, int request = AUDIO_PLAY)
.. c:function:: int ioctl(int fd, AUDIO_PLAY)
:name: AUDIO_PLAY
Arguments
@ -32,13 +34,6 @@ Arguments
- File descriptor returned by a previous call to open().
- .. row 2
- int request
- Equals AUDIO_PLAY for this command.
Description
-----------

14
Documentation/media/uapi/dvb/audio-select-source.rst
View File

@ -11,11 +11,13 @@ Name
AUDIO_SELECT_SOURCE
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: int ioctl(int fd, int request = AUDIO_SELECT_SOURCE, audio_stream_source_t source)
.. c:function:: int ioctl(int fd, AUDIO_SELECT_SOURCE, struct audio_stream_source *source)
:name: AUDIO_SELECT_SOURCE
Arguments
@ -26,19 +28,13 @@ Arguments
:stub-columns: 0
- .. row 1
-
- int fd
- File descriptor returned by a previous call to open().
- .. row 2
- int request
- Equals AUDIO_SELECT_SOURCE for this command.
- .. row 3
-
- audio_stream_source_t source

16
Documentation/media/uapi/dvb/audio-set-attributes.rst
View File

@ -11,12 +11,14 @@ Name
AUDIO_SET_ATTRIBUTES
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: int ioctl(fd, int request = AUDIO_SET_ATTRIBUTES, audio_attributes_t attr )
.. c:function:: int ioctl(fd, AUDIO_SET_ATTRIBUTES, struct audio_attributes *attr )
:name: AUDIO_SET_ATTRIBUTES
Arguments
---------
@ -26,19 +28,13 @@ Arguments
:stub-columns: 0
- .. row 1
-
- int fd
- File descriptor returned by a previous call to open().
- .. row 2
- int request
- Equals AUDIO_SET_ATTRIBUTES for this command.
- .. row 3
-
- audio_attributes_t attr

24
Documentation/media/uapi/dvb/audio-set-av-sync.rst
View File

@ -11,11 +11,13 @@ Name
AUDIO_SET_AV_SYNC
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: int ioctl(int fd, int request = AUDIO_SET_AV_SYNC, boolean state)
.. c:function:: int ioctl(int fd, AUDIO_SET_AV_SYNC, boolean state)
:name: AUDIO_SET_AV_SYNC
Arguments
@ -26,33 +28,21 @@ Arguments
:stub-columns: 0
- .. row 1
-
- int fd
- File descriptor returned by a previous call to open().
- .. row 2
- int request
- Equals AUDIO_AV_SYNC for this command.
- .. row 3
-
- boolean state
- Tells the DVB subsystem if A/V synchronization shall be ON or OFF.
- .. row 4
TRUE: AV-sync ON
-
- TRUE AV-sync ON
- .. row 5
-
- FALSE AV-sync OFF
FALSE: AV-sync OFF
Description

25
Documentation/media/uapi/dvb/audio-set-bypass-mode.rst
View File

@ -11,12 +11,13 @@ Name
AUDIO_SET_BYPASS_MODE
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: int ioctl(int fd, int request = AUDIO_SET_BYPASS_MODE, boolean mode)
.. c:function:: int ioctl(int fd, AUDIO_SET_BYPASS_MODE, boolean mode)
:name: AUDIO_SET_BYPASS_MODE
Arguments
---------
@ -26,34 +27,22 @@ Arguments
:stub-columns: 0
- .. row 1
-
- int fd
- File descriptor returned by a previous call to open().
- .. row 2
- int request
- Equals AUDIO_SET_BYPASS_MODE for this command.
- .. row 3
-
- boolean mode
- Enables or disables the decoding of the current Audio stream in
the DVB subsystem.
- .. row 4
TRUE: Bypass is disabled
-
- TRUE Bypass is disabled
- .. row 5
-
- FALSE Bypass is enabled
FALSE: Bypass is enabled
Description

15
Documentation/media/uapi/dvb/audio-set-ext-id.rst
View File

@ -11,12 +11,13 @@ Name
AUDIO_SET_EXT_ID
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: int ioctl(fd, int request = AUDIO_SET_EXT_ID, int id)
.. c:function:: int ioctl(fd, AUDIO_SET_EXT_ID, int id)
:name: AUDIO_SET_EXT_ID
Arguments
---------
@ -26,19 +27,13 @@ Arguments
:stub-columns: 0
- .. row 1
-
- int fd
- File descriptor returned by a previous call to open().
- .. row 2
- int request
- Equals AUDIO_SET_EXT_ID for this command.
- .. row 3
-
- int id

15
Documentation/media/uapi/dvb/audio-set-id.rst
View File

@ -11,12 +11,13 @@ Name
AUDIO_SET_ID
.. attention:: This ioctl is deprecated
Synopsis
--------
.. cpp:function:: int ioctl(int fd, int request = AUDIO_SET_ID, int id)
.. c:function:: int ioctl(int fd, AUDIO_SET_ID, int id)
:name: AUDIO_SET_ID
Arguments
---------
@ -26,19 +27,13 @@ Arguments
:stub-columns: 0
- .. row 1
-
- int fd
- File descriptor returned by a previous call to open().
- .. row 2
- int request
- Equals AUDIO_SET_ID for this command.
- .. row 3
-
- int id

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