This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.
Hardware tag-based KASAN won't be using shadow memory, but will reuse this
function. Rename "shadow" to implementation-neutral "metadata".
No functional changes.
Link: https://lkml.kernel.org/r/dd955c5aadaee16aef451a6189d19172166a23f5.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.
Hardware tag-based KASAN won't be using shadow memory, but will reuse this
function. Rename "shadow" to implementation-neutral "metadata".
No functional changes.
Link: https://lkml.kernel.org/r/370466fba590a4596b55ffd38adfd990f8886db4.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Software tag-based KASAN mode is fully initialized with kasan_init_tags(),
while the generic mode only requires kasan_init(). Move the
initialization message for tag-based mode into kasan_init_tags().
Also fix pr_fmt() usage for KASAN code: generic.c doesn't need it as it
doesn't use any printing functions; tag-based mode should use "kasan:"
instead of KBUILD_MODNAME (which stands for file name).
Link: https://lkml.kernel.org/r/29a30ea4e1750450dd1f693d25b7b6cb05913ecf.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.
Hardware tag-based KASAN won't use kasan_depth. Only define and use it
when one of the software KASAN modes are enabled.
No functional changes for software modes.
Link: https://lkml.kernel.org/r/e16f15aeda90bc7fb4dfc2e243a14b74cc5c8219.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.
Hardware tag-based KASAN won't be using shadow memory. Only initialize it
when one of the software KASAN modes are enabled.
No functional changes for software modes.
Link: https://lkml.kernel.org/r/d1742eea2cd728d150d49b144e49b6433405c7ba.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.
For software KASAN modes the check is based on the value in the shadow
memory. Hardware tag-based KASAN won't be using shadow, so hide the
implementation of the check in check_invalid_free().
Also simplify the code for software tag-based mode.
No functional changes for software modes.
Link: https://lkml.kernel.org/r/d01534a4b977f97d87515dc590e6348e1406de81.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Rename generic_report.c to report_generic.c and tags_report.c to
report_sw_tags.c, as their content is more relevant to report.c file.
Also rename tags.c to sw_tags.c to better reflect that this file contains
code for software tag-based mode.
No functional changes.
Link: https://lkml.kernel.org/r/a6105d416da97d389580015afed66c4c3cfd4c08.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Define KASAN_MEMORY_PER_SHADOW_PAGE as (KASAN_GRANULE_SIZE << PAGE_SHIFT),
which is the same as (KASAN_GRANULE_SIZE * PAGE_SIZE) for software modes
that use shadow memory, and use it across KASAN code to simplify it.
Link: https://lkml.kernel.org/r/8329391cfe14b5cffd3decf3b5c535b6ce21eef6.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.
The new mode won't be using shadow memory. Move all shadow-related code
to shadow.c, which is only enabled for software KASAN modes that use
shadow memory.
No functional changes for software modes.
Link: https://lkml.kernel.org/r/17d95cfa7d5cf9c4fcd9bf415f2a8dea911668df.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.
The new mode won't be using shadow memory, so only build init.c that
contains shadow initialization code for software modes.
No functional changes for software modes.
Link: https://lkml.kernel.org/r/bae0a6a35b7a9b1a443803c1a55e6e3fecc311c9.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.
The new mode won't be using shadow memory, but will still use the concept
of memory granules. Each memory granule maps to a single metadata entry:
8 bytes per one shadow byte for generic mode, 16 bytes per one shadow byte
for software tag-based mode, and 16 bytes per one allocation tag for
hardware tag-based mode.
Rename KASAN_SHADOW_SCALE_SIZE to KASAN_GRANULE_SIZE, and
KASAN_SHADOW_MASK to KASAN_GRANULE_MASK.
Also use MASK when used as a mask, otherwise use SIZE.
No functional changes.
Link: https://lkml.kernel.org/r/939b5754e47f528a6e6a6f28ffc5815d8d128033.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.
Group shadow-related KASAN function declarations and only define them for
the two existing software modes.
No functional changes for software modes.
Link: https://lkml.kernel.org/r/35126.1606402815@turing-police
Link: https://lore.kernel.org/linux-arm-kernel/24105.1606397102@turing-police/
Link: https://lkml.kernel.org/r/e88d94eff94db883a65dca52e1736d80d28dd9bc.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
[valdis.kletnieks@vt.edu: fix build issue with asmlinkage]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is a preparatory commit for the upcoming addition of a new hardware
tag-based (MTE-based) KASAN mode.
Group all vmalloc-related function declarations in include/linux/kasan.h,
and their implementations in mm/kasan/common.c.
No functional changes.
Link: https://lkml.kernel.org/r/80a6fdd29b039962843bd6cf22ce2643a7c8904e.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "kasan: add hardware tag-based mode for arm64", v11.
This patchset adds a new hardware tag-based mode to KASAN [1]. The new
mode is similar to the existing software tag-based KASAN, but relies on
arm64 Memory Tagging Extension (MTE) [2] to perform memory and pointer
tagging (instead of shadow memory and compiler instrumentation).
This patchset is co-developed and tested by
Vincenzo Frascino <vincenzo.frascino@arm.com>.
This patchset is available here:
https://github.com/xairy/linux/tree/up-kasan-mte-v11
For testing in QEMU hardware tag-based KASAN requires:
1. QEMU built from master [4] (use "-machine virt,mte=on -cpu max" arguments
to run).
2. GCC version 10.
[1] https://www.kernel.org/doc/html/latest/dev-tools/kasan.html
[2] https://community.arm.com/developer/ip-products/processors/b/processors-ip-blog/posts/enhancing-memory-safety
[3] git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux for-next/mte
[4] https://github.com/qemu/qemu
====== Overview
The underlying ideas of the approach used by hardware tag-based KASAN are:
1. By relying on the Top Byte Ignore (TBI) arm64 CPU feature, pointer tags
are stored in the top byte of each kernel pointer.
2. With the Memory Tagging Extension (MTE) arm64 CPU feature, memory tags
for kernel memory allocations are stored in a dedicated memory not
accessible via normal instuctions.
3. On each memory allocation, a random tag is generated, embedded it into
the returned pointer, and the corresponding memory is tagged with the
same tag value.
4. With MTE the CPU performs a check on each memory access to make sure
that the pointer tag matches the memory tag.
5. On a tag mismatch the CPU generates a tag fault, and a KASAN report is
printed.
Same as other KASAN modes, hardware tag-based KASAN is intended as a
debugging feature at this point.
====== Rationale
There are two main reasons for this new hardware tag-based mode:
1. Previously implemented software tag-based KASAN is being successfully
used on dogfood testing devices due to its low memory overhead (as
initially planned). The new hardware mode keeps the same low memory
overhead, and is expected to have significantly lower performance
impact, due to the tag checks being performed by the hardware.
Therefore the new mode can be used as a better alternative in dogfood
testing for hardware that supports MTE.
2. The new mode lays the groundwork for the planned in-kernel MTE-based
memory corruption mitigation to be used in production.
====== Technical details
Considering the implementation perspective, hardware tag-based KASAN is
almost identical to the software mode. The key difference is using MTE
for assigning and checking tags.
Compared to the software mode, the hardware mode uses 4 bits per tag, as
dictated by MTE. Pointer tags are stored in bits [56:60), the top 4 bits
have the normal value 0xF. Having less distict tags increases the
probablity of false negatives (from ~1/256 to ~1/16) in certain cases.
Only synchronous exceptions are set up and used by hardware tag-based KASAN.
====== Benchmarks
Note: all measurements have been performed with software emulation of Memory
Tagging Extension, performance numbers for hardware tag-based KASAN on the
actual hardware are expected to be better.
Boot time [1]:
* 2.8 sec for clean kernel
* 5.7 sec for hardware tag-based KASAN
* 11.8 sec for software tag-based KASAN
* 11.6 sec for generic KASAN
Slab memory usage after boot [2]:
* 7.0 kb for clean kernel
* 9.7 kb for hardware tag-based KASAN
* 9.7 kb for software tag-based KASAN
* 41.3 kb for generic KASAN
Measurements have been performed with:
* defconfig-based configs
* Manually built QEMU master
* QEMU arguments: -machine virt,mte=on -cpu max
* CONFIG_KASAN_STACK_ENABLE disabled
* CONFIG_KASAN_INLINE enabled
* clang-10 as the compiler and gcc-10 as the assembler
[1] Time before the ext4 driver is initialized.
[2] Measured as `cat /proc/meminfo | grep Slab`.
====== Notes
The cover letter for software tag-based KASAN patchset can be found here:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0116523cfffa62aeb5aa3b85ce7419f3dae0c1b8
===== Tags
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
This patch (of 41):
Don't mention "GNU General Public License version 2" text explicitly, as
it's already covered by the SPDX-License-Identifier.
Link: https://lkml.kernel.org/r/cover.1606161801.git.andreyknvl@google.com
Link: https://lkml.kernel.org/r/6ea9f5f4aa9dbbffa0d0c0a780b37699a4531034.1606161801.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current pattern in the file entry does not make the files in the
governors subdirectory to be a part of the CPU IDLE TIME MANAGEMENT
FRAMEWORK.
Adjust the file pattern to include files in governors.
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ext4_bio_write_page does not need wbc parameter, since its parameter
io contains the io_wbc field. The io::io_wbc is initialized by
ext4_io_submit_init which is called in ext4_writepages and
ext4_writepage functions prior to ext4_bio_write_page.
Therefor, when ext4_bio_write_page is called, wbc info
has already been included in io parameter.
Signed-off-by: Lei Chen <lennychen@tencent.com>
Link: https://lore.kernel.org/r/1607669664-25656-1-git-send-email-lennychen@tencent.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Commit cfd7323772 ("ext4: add prefetching for block allocation
bitmaps") introduced block bitmap prefetch, and expects to read block
bitmaps of flex_bg through an IO. However, it seems to ignore the
value range of s_log_groups_per_flex. In the scenario where the value
of s_log_groups_per_flex is greater than 27, s_mb_prefetch or
s_mb_prefetch_limit will overflow, cause a divide zero exception.
In addition, the logic of calculating nr is also flawed, because the
size of flexbg is fixed during a single mount, but s_mb_prefetch can
be modified, which causes nr to fail to meet the value condition of
[1, flexbg_size].
To solve this problem, we need to set the upper limit of
s_mb_prefetch. Since we expect to load block bitmaps of a flex_bg
through an IO, we can consider determining a reasonable upper limit
among the IO limit parameters. After consideration, we chose
BLK_MAX_SEGMENT_SIZE. This is a good choice to solve divide zero
problem and avoiding performance degradation.
[ Some minor code simplifications to make the changes easy to follow -- TYT ]
Reported-by: Tosk Robot <tencent_os_robot@tencent.com>
Signed-off-by: Chunguang Xu <brookxu@tencent.com>
Reviewed-by: Samuel Liao <samuelliao@tencent.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/1607051143-24508-1-git-send-email-brookxu@tencent.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
When filesystem inconsistency is detected with group locked, we
currently try to modify superblock to store error there without
blocking. However this can cause superblock checksum failures (or
DIF/DIX failure) when the superblock is just being written out.
Make error handling code just store error information in ext4_sb_info
structure and copy it to on-disk superblock only in ext4_commit_super().
In case of error happening with group locked, we just postpone the
superblock flushing to a workqueue.
[ Added fixup so that s_first_error_* does not get updated after
the file system is remounted.
Also added fix for syzbot failure. - Ted ]
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201127113405.26867-8-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: Hillf Danton <hdanton@sina.com>
Reported-by: syzbot+9043030c040ce1849a60@syzkaller.appspotmail.com
* pm-cpufreq:
cpufreq: intel_pstate: Use most recent guaranteed performance values
cpufreq: intel_pstate: Implement the ->adjust_perf() callback
cpufreq: Add special-purpose fast-switching callback for drivers
cpufreq: schedutil: Add util to struct sg_cpu
cppc_cpufreq: replace per-cpu data array with a list
cppc_cpufreq: expose information on frequency domains
cppc_cpufreq: clarify support for coordination types
cppc_cpufreq: use policy->cpu as driver of frequency setting
ACPI: processor: fix NONE coordination for domain mapping failure
ACPI: processor: Drop duplicate setting of shared_cpu_map
Voltages and current are reported by Zen CPUs. However, the means
to do so is undocumented, changes from CPU to CPU, and the raw data
is not calibrated. Calibration information is available, but again
not documented. This results in less than perfect user experience,
up to concerns that loading the driver might possibly damage
the hardware (by reporting out-of range voltages). Effectively
support for reporting voltages and current is not maintainable.
Drop it.
Cc: Artem S. Tashkinov <aros@gmx.com>
Cc: Wei Huang <wei.huang2@amd.com>
Tested-by: Wei Huang <wei.huang2@amd.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Update copyrights for files that have gotten some major rewrites lately.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
There is no point in duplicating the file name in the top of the file
comment.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
fs/block_dev.c is a pretty integral part of the block layer, so make
sure it is mentioned in MAINTAINERS.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This Acer Veriton N4640G/N6640G/N2510G desktops have 2 headphone
jacks(front and rear), and a separate Mic In jack.
The rear headphone jack is actually a line out jack but always silent
while playing audio. The front 'Mic In' also fails the jack sensing.
Apply the ALC269_FIXUP_LIFEBOOK to have all audio jacks to work as
expected.
Signed-off-by: Chris Chiu <chiu@endlessos.org>
Signed-off-by: Jian-Hong Pan <jhp@endlessos.org>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20201222150459.9545-2-chiu@endlessos.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
The Quanta NL3 laptop has both a headphone output jack and a headset
jack, on the right edge of the chassis.
The pin information suggests that both of these are at the Front.
The PulseAudio is confused to differentiate them so one of the jack
can neither get the jack sense working nor the audio output.
The ALC269_FIXUP_LIFEBOOK chained with ALC269_FIXUP_QUANTA_MUTE can
help to differentiate 2 jacks and get the 'Auto-Mute Mode' working
correctly.
Signed-off-by: Chris Chiu <chiu@endlessos.org>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20201222150459.9545-1-chiu@endlessos.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
* acpi-scan:
ACPI: scan: Add Intel Baytrail Mailbox Device to acpi_ignore_dep_ids
ACPI: scan: Avoid unnecessary second pass in acpi_bus_scan()
ACPI: scan: Defer enumeration of devices with _DEP lists
ACPI: scan: Evaluate _DEP before adding the device
* acpi-pnp:
ACPI: PNP: compare the string length in the matching_id()
* acpi-sleep:
ACPI: PM: s2idle: Move x86-specific code to the x86 directory
ACPI: PM: s2idle: Add AMD support to handle _DSM
The BOSS GT-1 (USB ID 0582:01d6) requires implicit feedback
like other similar BOSS devices. This patch adds this support.
[ rearranged the table entry in the ID order -- tiwai ]
Signed-off-by: Mike Oliphant <oliphant@nostatic.org>
Link: https://lore.kernel.org/r/20201221215533.2511-1-oliphant@nostatic.org
Signed-off-by: Takashi Iwai <tiwai@suse.de>
memblock_enforce_memory_limit accepts the maximum memory size not the
maximum address that can be handled by kernel. Fix the function invocation
accordingly.
Fixes: 1bd14a66ee ("RISC-V: Remove any memblock representing unusable memory area")
Cc: stable@vger.kernel.org
Reported-by: Bin Meng <bin.meng@windriver.com>
Tested-by: Bin Meng <bin.meng@windriver.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
this is one of the cases where we need to use d_real() - we are
using more than the name of dentry here. ->d_sb is used as well,
so in case of hostfs being used as a layer we get the wrong
superblock.
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Tested-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The definition of IS_ERR() already applies the unlikely() notation
when checking the error status of the passed pointer. For this
reason there is no need to have the same notation outside of
IS_ERR() itself.
Clean up code by removing redundant notation.
Signed-off-by: Antonio Quartulli <a@unstable.cc>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
If emergency system shutdown is called, like by thermal shutdown,
a dm device could be alive when the block device couldn't process
I/O requests anymore. In this state, the handling of I/O errors
by new dm I/O requests or by those already in-flight can lead to
a verity corruption state, which is a misjudgment.
So, skip verity work in response to I/O error when system is shutting
down.
Signed-off-by: Hyeongseok Kim <hyeongseok@gmail.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
ability to get struct clk pointers from a struct clk_hw so that clk providers
can consume the clks they provide, if they need to do something like that. This
has been a long missing part of the clk provider API that will help us move
away from exposing a struct clk pointer in the struct clk_hw. Tracepoints are
added for the clk_set_rate() "range" functions, similar to the tracepoints we
already have for clk_set_rate() and we added a column to debugfs to help
developers understand the hardware enable state of clks in case firmware or
bootloader state is different than what is expected. Overall the core changes
are mostly improving the clk driver writing experience.
At the driver level, we have the usual collection of driver updates and new
drivers for new SoCs. This time around the Qualcomm folks introduced a good
handful of clk drivers for various parts of three or four SoCs. The SiFive
folks added a new clk driver for their FU740 SoCs, coming in second on the
diffstat and then Atmel AT91 and Amlogic SoCs had lots of work done after that
for various new features. One last thing to note in the driver area is that the
i.MX driver has gained a new binding to support SCU clks after being on the
list for many months. It uses a two cell binding which is sort of rare in clk
DT bindings. Beyond that we have the usual set of driver fixes and tweaks that
come from more testing and finding out that some configuration was wrong or
that a driver could support being built as a module.
Core:
- Add some trace points for clk_set_rate() "range" functions
- Add hardware enable information to clk_summary debugfs
- Replace clk-provider.h with of_clk.h when possible
- Add devm variant of clk_notifier_register()
- Add clk_hw_get_clk() to generate a struct clk from a struct clk_hw
New Drivers:
- Bindings for Canaan K210 SoC clks
- Support for SiFive FU740 PRCI
- Camera clks on Qualcomm SC7180 SoCs
- GCC and RPMh clks on Qualcomm SDX55 SoCs
- RPMh clks on Qualcomm SM8350 SoCs
- LPASS clks on Qualcomm SM8250 SoCs
Updates:
- DVFS support for AT91 clk driver
- Update git repo branch for Renesas clock drivers
- Add camera (CSI) and video-in (VIN) clocks on Renesas R-Car V3U
- Add RPC (QSPI/HyperFLASH) clocks on Renesas RZ/G2M, RZ/G2N, and RZ/G2E
- Stop using __raw_*() I/O accessors in Renesas clk drivers
- One more conversion of DT bindings to json-schema
- Make i.MX clk-gate2 driver more flexible
- New two cell binding for i.MX SCU clks
- Drop of_match_ptr() in i.MX8 clk drivers
- Add arch dependencies for Rockchip clk drivers
- Fix i2s on Rockchip rk3066
- Add MIPI DSI clks on Amlogic axg and g12 SoCs
- Support modular builds of Amlogic clk drivers
- Fix an Amlogic Video PLL clock dependency
- Samsung Kconfig dependencies updates for better compile test coverage
- Refactoring of the Samsung PLL clocks driver
- Small Tegra driver cleanups
- Minor fixes to Ingenic and VC5 clk drivers
- Cleanup patches to remove unused variables and plug memory leaks
-----BEGIN PGP SIGNATURE-----
iQJFBAABCAAvFiEE9L57QeeUxqYDyoaDrQKIl8bklSUFAl/f/ycRHHNib3lkQGtl
cm5lbC5vcmcACgkQrQKIl8bklSXjxg/7BJMFphpZmQb3iy/lZMYfgPh2yxZvrrBj
zJ2i1mMru/C3BkXTx29HCJvj6/VC2HgGLL6fzfwe7oY3XVRT1Vxlsvka9vNZSNc2
UYNa8GUwR0mSXDzp5KnzoAQfLwvSqWUIeT8WB+Z+CJ7WIAGWnXgBlqsf/d/mr9hg
JoAh+ROpbksL6hs61WJSm+7/Yu6efS0Yj0zzLZOINFWvDIOJ+Rp4g1u+qGH9tZyO
I2Bik75Sc8hqvLUP5SVzI/1H4yLB0On+ADgVRwjvrKPVX56alYquOUMsU+sy4SeY
ONQBki3vV5gtJHG1qvkwTC5/Yw20eUsrmrc7PNECvb1zo5Tp4QuOAR5nHCb4fg8u
n7RRd1MktTAUAQxTzBaNYtix3Q19fjSR44C/1B6lKk6xkN+w4uYLi2GHrADy9rXa
SwQVTKTGc8LjGywDaAOXdAyx2FMAtt1OvkTxZ238+aoHw5nQDHWKxu5TwYK6b5jG
aEFzTCIEYlzRLqcZyGONSD0WXmQWyoNiPwJ3B7RDRfpg7dPESyKIB4MzGWiX9eDy
lri/SoVH08c1sRf8AzIoi+CUNi8geTNAHHlJfiGznrv81ttVf3FioWyWLjr+SmBV
rNxn35WxeDWoCZqtrLJlg5skVgmD8BRXLZTI9udPG8u6D7OdWdJBuMZ6EelO+OZg
/n4w8tdo3cE=
=Wt9O
-----END PGP SIGNATURE-----
Merge tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux
Pull clk updates from Stephen Boyd:
"The core framework got some nice improvements this time around. We
gained the ability to get struct clk pointers from a struct clk_hw so
that clk providers can consume the clks they provide, if they need to
do something like that. This has been a long missing part of the clk
provider API that will help us move away from exposing a struct clk
pointer in the struct clk_hw. Tracepoints are added for the
clk_set_rate() "range" functions, similar to the tracepoints we
already have for clk_set_rate() and we added a column to debugfs to
help developers understand the hardware enable state of clks in case
firmware or bootloader state is different than what is expected.
Overall the core changes are mostly improving the clk driver writing
experience.
At the driver level, we have the usual collection of driver updates
and new drivers for new SoCs. This time around the Qualcomm folks
introduced a good handful of clk drivers for various parts of three or
four SoCs. The SiFive folks added a new clk driver for their FU740
SoCs, coming in second on the diffstat and then Atmel AT91 and Amlogic
SoCs had lots of work done after that for various new features. One
last thing to note in the driver area is that the i.MX driver has
gained a new binding to support SCU clks after being on the list for
many months. It uses a two cell binding which is sort of rare in clk
DT bindings. Beyond that we have the usual set of driver fixes and
tweaks that come from more testing and finding out that some
configuration was wrong or that a driver could support being built as
a module.
Summary:
Core:
- Add some trace points for clk_set_rate() "range" functions
- Add hardware enable information to clk_summary debugfs
- Replace clk-provider.h with of_clk.h when possible
- Add devm variant of clk_notifier_register()
- Add clk_hw_get_clk() to generate a struct clk from a struct clk_hw
New Drivers:
- Bindings for Canaan K210 SoC clks
- Support for SiFive FU740 PRCI
- Camera clks on Qualcomm SC7180 SoCs
- GCC and RPMh clks on Qualcomm SDX55 SoCs
- RPMh clks on Qualcomm SM8350 SoCs
- LPASS clks on Qualcomm SM8250 SoCs
Updates:
- DVFS support for AT91 clk driver
- Update git repo branch for Renesas clock drivers
- Add camera (CSI) and video-in (VIN) clocks on Renesas R-Car V3U
- Add RPC (QSPI/HyperFLASH) clocks on Renesas RZ/G2M, RZ/G2N, and RZ/G2E
- Stop using __raw_*() I/O accessors in Renesas clk drivers
- One more conversion of DT bindings to json-schema
- Make i.MX clk-gate2 driver more flexible
- New two cell binding for i.MX SCU clks
- Drop of_match_ptr() in i.MX8 clk drivers
- Add arch dependencies for Rockchip clk drivers
- Fix i2s on Rockchip rk3066
- Add MIPI DSI clks on Amlogic axg and g12 SoCs
- Support modular builds of Amlogic clk drivers
- Fix an Amlogic Video PLL clock dependency
- Samsung Kconfig dependencies updates for better compile test coverage
- Refactoring of the Samsung PLL clocks driver
- Small Tegra driver cleanups
- Minor fixes to Ingenic and VC5 clk drivers
- Cleanup patches to remove unused variables and plug memory leaks"
* tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux: (134 commits)
dt-binding: clock: Document canaan,k210-clk bindings
dt-bindings: Add Canaan vendor prefix
clk: vc5: Use "idt,voltage-microvolt" instead of "idt,voltage-microvolts"
clk: ingenic: Fix divider calculation with div tables
clk: sunxi-ng: Make sure divider tables have sentinel
clk: s2mps11: Fix a resource leak in error handling paths in the probe function
clk: mvebu: a3700: fix the XTAL MODE pin to MPP1_9
clk: si5351: Wait for bit clear after PLL reset
clk: at91: sam9x60: remove atmel,osc-bypass support
clk: at91: sama7g5: register cpu clock
clk: at91: clk-master: re-factor master clock
clk: at91: sama7g5: do not allow cpu pll to go higher than 1GHz
clk: at91: sama7g5: decrease lower limit for MCK0 rate
clk: at91: sama7g5: remove mck0 from parent list of other clocks
clk: at91: clk-sam9x60-pll: allow runtime changes for pll
clk: at91: sama7g5: add 5th divisor for mck0 layout and characteristics
clk: at91: clk-master: add 5th divisor for mck master
clk: at91: sama7g5: allow SYS and CPU PLLs to be exported and referenced in DT
dt-bindings: clock: at91: add sama7g5 pll defines
clk: at91: sama7g5: fix compilation error
...
- fix long-standing limitation on open-unlink-fop pattern
- add refcount to p9_fid (fixes the above and will allow for more
cleanups and simplifications in the future)
-----BEGIN PGP SIGNATURE-----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=DKlc
-----END PGP SIGNATURE-----
Merge tag '9p-for-5.11-rc1' of git://github.com/martinetd/linux
Pull 9p update from Dominique Martinet:
- fix long-standing limitation on open-unlink-fop pattern
- add refcount to p9_fid (fixes the above and will allow for more
cleanups and simplifications in the future)
* tag '9p-for-5.11-rc1' of git://github.com/martinetd/linux:
9p: Remove unnecessary IS_ERR() check
9p: Uninitialized variable in v9fs_writeback_fid()
9p: Fix writeback fid incorrectly being attached to dentry
9p: apply review requests for fid refcounting
9p: add refcount to p9_fid struct
fs/9p: search open fids first
fs/9p: track open fids
fs/9p: fix create-unlink-getattr idiom
Since the default value of sysctl_max_map_count is defined as
DEFAULT_MAX_MAP_COUNT from mm/util.c
int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
DEFAULT_MAX_MAP_COUNT is defined as 65530 (65535-5) in include/linux/mm.h
#define MAPCOUNT_ELF_CORE_MARGIN (5)
#define DEFAULT_MAX_MAP_COUNT (USHRT_MAX - MAPCOUNT_ELF_CORE_MARGIN)
Signed-off-by: Fengfei Xi <xi.fengfei@h3c.com>
Link: https://lore.kernel.org/r/20201210082134.36957-1-xi.fengfei@h3c.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
We need r1 to be properly set before activating MMU, otherwise any new
exception taken while saving registers into the stack in syscall
prologs will use the user stack, which is wrong and will even lockup
or crash when KUAP is selected.
Do that by switching the meaning of r11 and r1 until we have saved r1
to the stack: copy r1 into r11 and setup the new stack pointer in r1.
To avoid complicating and impacting all generic and specific prolog
code (and more), copy back r1 into r11 once r11 is save onto
the stack.
We could get rid of copying r1 back and forth at the cost of rewriting
everything to use r1 instead of r11 all the way when CONFIG_VMAP_STACK
is set, but the effort is probably not worth it for now.
Fixes: da7bb43ab9 ("powerpc/32: Fix vmap stack - Properly set r1 before activating MMU")
Cc: stable@vger.kernel.org # v5.10+
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/a3d819d5c348cee9783a311d5d3f3ba9b48fd219.1608531452.git.christophe.leroy@csgroup.eu
The early ATAGS/DT mapping code uses SECTION_SHIFT to mask low order
bits of R2, and decides that no ATAGS/DTB were provided if the resulting
value is 0x0.
This means that on systems where DRAM starts at 0x0 (such as Raspberry
Pi), no explicit mapping of the DT will be created if R2 points into the
first 1 MB section of memory. This was not a problem before, because the
decompressed kernel is loaded at the base of DRAM and mapped using
sections as well, and so as long as the DT is referenced via a virtual
address that uses the same translation (the linear map, in this case),
things work fine.
However, commit 7a1be318f5 ("9012/1: move device tree mapping out of
linear region") changes this, and now the DT is referenced via a virtual
address that is disjoint from the linear mapping of DRAM, and so we need
the early code to create the DT mapping unconditionally.
So let's create the early DT mapping for any value of R2 != 0x0.
Reported-by: "kernelci.org bot" <bot@kernelci.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Andrey Konovalov