The windfarm code uses a struct device_driver instead of
platform_driver, which can cause crashes if any of the callbacks are
called (like on module removal). This fixes it.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
m68k_handle_int() split in two functions: __m68k_handle_int() takes
pt_regs * and does set_irq_regs(); m68k_handle_int() doesn't get pt_regs
*.
Places where we used to call m68k_handle_int() recursively with the same
pt_regs have simply lost the second argument, the rest is switched to
__m68k_handle_int().
The rest of patch is just dropping pt_regs * where needed.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix up some of the buildbreaks from the irq handler changes.
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.
The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around. On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).
Where appropriate, an arch may override the generic storage facility and do
something different with the variable. On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.
Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions. Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller. A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.
I've build this code with allyesconfig for x86_64 and i386. I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.
This will affect all archs. Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:
struct pt_regs *old_regs = set_irq_regs(regs);
And put the old one back at the end:
set_irq_regs(old_regs);
Don't pass regs through to generic_handle_irq() or __do_IRQ().
In timer_interrupt(), this sort of change will be necessary:
- update_process_times(user_mode(regs));
- profile_tick(CPU_PROFILING, regs);
+ update_process_times(user_mode(get_irq_regs()));
+ profile_tick(CPU_PROFILING);
I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().
Some notes on the interrupt handling in the drivers:
(*) input_dev() is now gone entirely. The regs pointer is no longer stored in
the input_dev struct.
(*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does
something different depending on whether it's been supplied with a regs
pointer or not.
(*) Various IRQ handler function pointers have been moved to type
irq_handler_t.
Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
Many files include the filename at the beginning, serveral used a wrong one.
Signed-off-by: Uwe Zeisberger <Uwe_Zeisberger@digi.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
* git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc: (29 commits)
[POWERPC] Fix rheap alignment problem
[POWERPC] Use check_legacy_ioport() for ISAPnP
[POWERPC] Avoid NULL pointer in gpio1_interrupt
[POWERPC] Enable generic rtc hook for the MPC8349 mITX
[POWERPC] Add powerpc get/set_rtc_time interface to new generic rtc class
[POWERPC] Create a "wrapper" script and use it in arch/powerpc/boot
[POWERPC] fix spin lock nesting in hvc_iseries
[POWERPC] EEH failure to mark pci slot as frozen.
[POWERPC] update powerpc defconfig files after libata kconfig breakage
[POWERPC] enable sysrq in pmac32_defconfig
[POWERPC] UPIO_TSI cleanup
[POWERPC] rewrite mkprep and mkbugboot in sane C
[POWERPC] maple/pci iomem annotations
[POWERPC] powerpc oprofile __user annotations
[POWERPC] cell spufs iomem annotations
[POWERPC] NULL noise removal: spufs
[POWERPC] ppc math-emu needs -fno-builtin-fabs for math.c and fabs.c
[POWERPC] update mpc8349_itx_defconfig and remove some debug settings
[POWERPC] Always call cede in pseries dedicated idle loop
[POWERPC] Fix loop logic in irq_alloc_virt()
...
gpio1_interrupt() may dereference a NULL pointer if ioremap() fails.
But, maybe no gpio interrupt happens in the first place?
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
All on stack DECLARE_COMPLETIONs should be replaced by:
DECLARE_COMPLETION_ONSTACK
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
If we can clean up these remainders we can finally delete pci_find_*
Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Greg KH <greg@kroah.com>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The uninitialised pmu_backlight_lock causes the current Fedora test kernel
(which has spinlock debugging enabled) to panic on suspend.
This is suboptimal, so I fixed it.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix some more problems (inverted use of semaphores in some places). He
also moved my checks into within the protected section which is better.
Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The via-pmu backlight code (introduced in 2.6.18) has various design issues
causing crashes on machines using it like the old Wallstreet powerbook
(Michael, the author, never managed to test on these and I just got my hand
on one of those old beasts).
This fixes them by no longer trying to hijack the backlight device of the
frontmost framebuffer (causing that framebuffer to crash) but having it's
own local bits instead. Might look weird but it's better that way on those
old machines, at least as a last-minute fix for 2.6.18. We might rework
the whole thing later. This patch also changes the way it gets notified of
sleep and wakeup in order to properly shut the backlight down on sleep and
bring it back on wakeup.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc:
[POWERPC] Minor comment fix for misc_64.S
[POWERPC] Use H_CEDE on non-SMT
[POWERPC] force 64bit mode in fwnmi handlers to workaround firmware bugs
[POWERPC] PMAC_APM_EMU should depend on ADB_PMU
[POWERPC] Fix new interrupt code (MPIC detection)
[POWERPC] Fix new interrupt code (MPIC endianness)
[POWERPC] Add cpufreq support for Xserve G5
[POWERPC] Xserve G5 thermal control fixes
[POWERPC] Fix mem= handling when the memory limit is > RMO size
[POWERPC] More offb/bootx fixes
[POWERPC] Fix legacy_serial.c error handling on 32 bits
[POWERPC] Fix default clock for udbg_16550
[POWERPC] Fix non-MPIC CHRPs with CONFIG_SMP set
[POWERPC] Fix 32 bits warning in prom_init.c
[POWERPC] Workaround Pegasos incorrect ISA "ranges"
[POWERPC] fix up front-LED Kconfig
This patch fixes several problems:
- The legacy backlight value might be set at interrupt time. Introduced
a worker to prevent it from directly calling the backlight code.
- via-pmu allows the backlight to be grabbed, in which case we need to
prevent other kernel code from changing the brightness.
- Don't send PMU requests in via-pmu-backlight when the machine is about
to sleep or waking up.
- More Kconfig fixes.
Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Now that get_property() returns a void *, there's no need to cast its
return value. Also, treat the return value as const, so we can
constify get_property later.
powermac platform & macintosh driver changes.
Built for pmac32_defconfig, g5_defconfig
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This patch fixes undefined refereneces to pmu_ symbols on 2.6.17.
Signed-Off-By: Danny van Dyk <kugelfang@gentoo.org>
Signed-off-by: Daniel Drake <dsd@gentoo.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The thermal control for the Xserve G5s had a few issues. For one, the
way to program the RPM fans speeds into the FCU is different between it
and the desktop models, which I didn't figure out until recently, and it
was missing a control loop for the slots fan, running it too fast. Both
of those problems were causing the machine to be much more noisy than
necessary. This patch also changes the fixed value of the slots fan for
desktop G5s to 40% instead of 50%. It seems to still have a pretty good
airflow that way and is much less noisy.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This patch fixes the front-LED Kconfig issues I introduced while
creating it. Apparently having a dependency isn't enough to have the
select not evaluated or something like that.
The patch also changes the default configuration for pmac32 select the
default for the LED to be the IDE trigger. While I was at it, I
completely updated the defconfig and also added snd-aoa to it.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This patch fixes several problems:
- pmac_backlight_key() is called under interrupt context, and therefore
can't use mutexes or semaphores, so defer the backlight level for
later, as it's not critical (original code by Aristeu S. Rozanski F.
<aris@valeta.org>).
- Add exports for functions that might be called from modules
- Fix Kconfig depdencies on PMAC_BACKLIGHT.
- Fix locking issues on calls from inside the driver (reported by
Aristeu S. Rozanski F., too)
- Fix wrong calculation of backlight values in some of the drivers
- Replace pmac_backlight_key_up/down by inline functions
[akpm@osdl.org: fix function prototypes]
Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Acked-by: Aristeu S. Rozanski F. <aris@valeta.org>
Acked-by: Rene Nussbaumer <linux-kernel@killerfox.forkbomb.ch>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The SMU driver tries to map an interrupt from the device-tree before the
interrupt controllers in the machine have been enumerated. This doesn't work
properly and cause machines like the Quad g5 to fail booting later on when
some drivers waits endlessly for an SMU request to complete. This is the
second problem preventing boot on the Quad g5. This fixes it and also makes
the SMU driver a bit more resilient to not having an interrupt.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch slightly reworks the new irq code to fix a small design error. I
removed the passing of the trigger to the map() calls entirely, it was not a
good idea to have one call do two different things. It also fixes a couple of
corner cases.
Mapping a linux virtual irq to a physical irq now does only that. Setting the
trigger is a different action which has a different call.
The main changes are:
- I no longer call host->ops->map() for an already mapped irq, I just return
the virtual number that was already mapped. It was called before to give an
opportunity to change the trigger, but that was causing issues as that could
happen while the interrupt was in use by a device, and because of the
trigger change, map would potentially muck around with things in a racy way.
That was causing much burden on a given's controller implementation of
map() to get it right. This is much simpler now. map() is only called on
the initial mapping of an irq, meaning that you know that this irq is _not_
being used. You can initialize the hardware if you want (though you don't
have to).
- Controllers that can handle different type of triggers (level/edge/etc...)
now implement the standard irq_chip->set_type() call as defined by the
generic code. That means that you can use the standard set_irq_type() to
configure an irq line manually if you wish or (though I don't like that
interface), pass explicit trigger flags to request_irq() as defined by the
generic kernel interfaces. Also, using those interfaces guarantees that
your controller set_type callback is called with the descriptor lock held,
thus providing locking against activity on the same interrupt (including
mask/unmask/etc...) automatically. A result is that, for example, MPIC's
own map() implementation calls irq_set_type(NONE) to configure the hardware
to the default triggers.
- To allow the above, the irq_map array entry for the new mapped interrupt
is now set before map() callback is called for the controller.
- The irq_create_of_mapping() (also used by irq_of_parse_and_map()) function
for mapping interrupts from the device-tree now also call the separate
set_irq_type(), and only does so if there is a change in the trigger type.
- While I was at it, I changed pci_read_irq_line() (which is the helper I
would expect most archs to use in their pcibios_fixup() to get the PCI
interrupt routing from the device tree) to also handle a fallback when the
DT mapping fails consisting of reading the PCI_INTERRUPT_PIN to know wether
the device has an interrupt at all, and the the PCI_INTERRUPT_LINE to get an
interrupt number from the device. That number is then mapped using the
default controller, and the trigger is set to level low. That default
behaviour works for several platforms that don't have a proper interrupt
tree like Pegasos. If it doesn't work for your platform, then either
provide a proper interrupt tree from the firmware so that fallback isn't
needed, or don't call pci_read_irq_line()
- Add back a bit that got dropped by my main rework patch for properly
clearing pending IPIs on pSeries when using a kexec
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The thermal control for the Xserve G5s had a few issues. For one, the
way to program the RPM fans speeds into the FCU is different between it
and the desktop models, which I didn't figure out until recently, and it
was missing a control loop for the slots fan, running it too fast. Both
of those problems were causing the machine to be much more noisy than
necessary. This patch also changes the fixed value of the slots fan for
desktop G5s to 40% instead of 50%. It seems to still have a pretty good
airflow that way and is much less noisy.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This adds the new irq remapper core and removes the old one. Because
there are some fundamental conflicts with the old code, like the value
of NO_IRQ which I'm now setting to 0 (as per discussions with Linus),
etc..., this commit also changes the relevant platform and driver code
over to use the new remapper (so as not to cause difficulties later
in bisecting).
This patch removes the old pre-parsing of the open firmware interrupt
tree along with all the bogus assumptions it made to try to renumber
interrupts according to the platform. This is all to be handled by the
new code now.
For the pSeries XICS interrupt controller, a single remapper host is
created for the whole machine regardless of how many interrupt
presentation and source controllers are found, and it's set to match
any device node that isn't a 8259. That works fine on pSeries and
avoids having to deal with some of the complexities of split source
controllers vs. presentation controllers in the pSeries device trees.
The powerpc i8259 PIC driver now always requests the legacy interrupt
range. It also has the feature of being able to match any device node
(including NULL) if passed no device node as an input. That will help
porting over platforms with broken device-trees like Pegasos who don't
have a proper interrupt tree.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The 64 bits resource patches did a bit of damage on PowerMac causing a
buffer overflow in macio_asic and a warning in a sound driver. The
former is fixed by reverting the sprintf of the bus_id to %08x as it was
before. The bus_id used for macio devices is always a 32 bits value
(macio always sits in 32 bits space) and since it's exposed to userland,
the format of the string shouldn't be changed like that anyway. The
second by using the proper type for printk.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/devfs-2.6: (22 commits)
[PATCH] devfs: Remove it from the feature_removal.txt file
[PATCH] devfs: Last little devfs cleanups throughout the kernel tree.
[PATCH] devfs: Rename TTY_DRIVER_NO_DEVFS to TTY_DRIVER_DYNAMIC_DEV
[PATCH] devfs: Remove the tty_driver devfs_name field as it's no longer needed
[PATCH] devfs: Remove the line_driver devfs_name field as it's no longer needed
[PATCH] devfs: Remove the videodevice devfs_name field as it's no longer needed
[PATCH] devfs: Remove the gendisk devfs_name field as it's no longer needed
[PATCH] devfs: Remove the miscdevice devfs_name field as it's no longer needed
[PATCH] devfs: Remove the devfs_fs_kernel.h file from the tree
[PATCH] devfs: Remove devfs_remove() function from the kernel tree
[PATCH] devfs: Remove devfs_mk_cdev() function from the kernel tree
[PATCH] devfs: Remove devfs_mk_bdev() function from the kernel tree
[PATCH] devfs: Remove devfs_mk_symlink() function from the kernel tree
[PATCH] devfs: Remove devfs_mk_dir() function from the kernel tree
[PATCH] devfs: Remove devfs_*_tape() functions from the kernel tree
[PATCH] devfs: Remove devfs support from the sound subsystem
[PATCH] devfs: Remove devfs support from the ide subsystem.
[PATCH] devfs: Remove devfs support from the serial subsystem
[PATCH] devfs: Remove devfs from the init code
[PATCH] devfs: Remove devfs from the partition code
...
* git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc: (43 commits)
[POWERPC] Use little-endian bit from firmware ibm,pa-features property
[POWERPC] Make sure smp_processor_id works very early in boot
[POWERPC] U4 DART improvements
[POWERPC] todc: add support for Time-Of-Day-Clock
[POWERPC] Make lparcfg.c work when both iseries and pseries are selected
[POWERPC] Fix idr locking in init_new_context
[POWERPC] mpc7448hpc2 (taiga) board config file
[POWERPC] Add tsi108 pci and platform device data register function
[POWERPC] Add general support for mpc7448hpc2 (Taiga) platform
[POWERPC] Correct the MAX_CONTEXT definition
powerpc: minor cleanups for mpc86xx
[POWERPC] Make sure we select CONFIG_NEW_LEDS if ADB_PMU_LED is set
[POWERPC] Simplify the code defining the 64-bit CPU features
[POWERPC] powerpc: kconfig warning fix
[POWERPC] Consolidate some of kernel/misc*.S
[POWERPC] Remove unused function call_with_mmu_off
[POWERPC] update asm-powerpc/time.h
[POWERPC] Clean up it_lp_queue.h
[POWERPC] Skip the "copy down" of the kernel if it is already at zero.
[POWERPC] Add the use of the firmware soft-reset-nmi to kdump.
...
This patch removes the old pmac ide led blink code and
adds generic LED subsystem support for the LED.
It maintains backward compatibility with the old
BLK_DEV_IDE_PMAC_BLINK Kconfig option which now
simply selects the new code and influences the
default trigger.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This is needed if we wish to change the size of the resource structures.
Based on an original patch from Vivek Goyal <vgoyal@in.ibm.com>
Cc: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fix a mispelling of the korean alphabet name in the input subsystem.
See http://en.wikipedia.org/wiki/Hangeul#Names for more details.
KEY_HANGUEL left to not break people
Signed-off-by: Jerome Pinot <ngc891@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Add an input device for the button and lid switch so that userspace gets
notified about the user pressing them via the standard input layer.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
This patch contains a total rewrite of the backlight infrastructure for
portable Apple computers. Backward compatibility is retained. A sysfs
interface allows userland to control the brightness with more steps than
before. Userland is allowed to upload a brightness curve for different
monitors, similar to Mac OS X.
[akpm@osdl.org: add needed exports]
Signed-off-by: Michael Hanselmann <linux-kernel@hansmi.ch>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This adds a vdso_base element to the mm_context_t for 32-bit compiles
(both for ARCH=powerpc and ARCH=ppc). This fixes the compile errors
that have been reported in arch/powerpc/kernel/signal_32.c.
Signed-off-by: Paul Mackerras <paulus@samba.org>
This fixes an oops in 2.6.16.X when loading the snd_powermac module. The
name of the requested module changed during the 2.6.16 development cycle
from i2c-keylargo to i2c-powermac.
Signed-off-by: Guido Guenther <agx@sigxcpu.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This removes statically assigned platform numbers and reworks the
powerpc platform probe code to use a better mechanism. With this,
board support files can simply declare a new machine type with a
macro, and implement a probe() function that uses the flattened
device-tree to detect if they apply for a given machine.
We now have a machine_is() macro that replaces the comparisons of
_machine with the various PLATFORM_* constants. This commit also
changes various drivers to use the new macro instead of looking at
_machine.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Benjamin Herrenschmidt