user/sven/linux.git/include/asm-generic/bitops, branch v5.19.9

locking/atomic: Make test_and_*_bit() ordered on failure

2022-08-25T09:45:06Z

commit 415d832497098030241605c52ea83d4e2cfa7879 upstream. These operations are documented as always ordered in include/asm-generic/bitops/instrumented-atomic.h, and producer-consumer type use cases where one side needs to ensure a flag is left pending after some shared data was updated rely on this ordering, even in the failure case. This is the case with the workqueue code, which currently suffers from a reproducible ordering violation on Apple M1 platforms (which are notoriously out-of-order) that ends up causing the TTY layer to fail to deliver data to userspace properly under the right conditions. This change fixes that bug. Change the documentation to restrict the "no order on failure" story to the _lock() variant (for which it makes sense), and remove the early-exit from the generic implementation, which is what causes the missing barrier semantics in that case. Without this, the remaining atomic op is fully ordered (including on ARM64 LSE, as of recent versions of the architecture spec). Suggested-by: Linus Torvalds Cc: stable@vger.kernel.org Fixes: e986a0d6cb36 ("locking/atomics, asm-generic/bitops/atomic.h: Rewrite using atomic_*() APIs") Fixes: 61e02392d3c7 ("locking/atomic/bitops: Document and clarify ordering semantics for failed test_and_{}_bit()") Signed-off-by: Hector Martin Acked-by: Will Deacon Reviewed-by: Arnd Bergmann Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

asm-generic/bitops: Always inline all bit manipulation helpers

2022-01-25T21:30:28Z

Make it consistent with the atomic/atomic-instrumented.h helpers. And defconfig size is actually going down! text data bss dec hex filename 22352096 8213152 1917164 32482412 1efa46c vmlinux.x86-64.defconfig.before 22350551 8213184 1917164 32480899 1ef9e83 vmlinux.x86-64.defconfig.after Suggested-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov Signed-off-by: Peter Zijlstra (Intel) Acked-by: Marco Elver Link: https://lore.kernel.org/r/20220113155357.4706-2-bp@alien8.de

Merge tag 'bitmap-5.17-rc1' of git://github.com/norov/linux

2022-01-23T04:20:44Z

Pull bitmap updates from Yury Norov: - introduce for_each_set_bitrange() - use find_first_*_bit() instead of find_next_*_bit() where possible - unify for_each_bit() macros * tag 'bitmap-5.17-rc1' of git://github.com/norov/linux: vsprintf: rework bitmap_list_string lib: bitmap: add performance test for bitmap_print_to_pagebuf bitmap: unify find_bit operations mm/percpu: micro-optimize pcpu_is_populated() Replace for_each_*_bit_from() with for_each_*_bit() where appropriate find: micro-optimize for_each_{set,clear}_bit() include/linux: move for_each_bit() macros from bitops.h to find.h cpumask: replace cpumask_next_* with cpumask_first_* where appropriate tools: sync tools/bitmap with mother linux all: replace find_next{,_zero}_bit with find_first{,_zero}_bit where appropriate cpumask: use find_first_and_bit() lib: add find_first_and_bit() arch: remove GENERIC_FIND_FIRST_BIT entirely include: move find.h from asm_generic to linux bitops: move find_bit_*_le functions from le.h to find.h bitops: protect find_first_{,zero}_bit properly

include: move find.h from asm_generic to linux

2022-01-15T16:47:31Z

find_bit API and bitmap API are closely related, but inclusion paths are different - include/asm-generic and include/linux, correspondingly. In the past it made a lot of troubles due to circular dependencies and/or undefined symbols. Fix this by moving find.h under include/linux. Signed-off-by: Yury Norov Tested-by: Wolfram Sang Acked-by: Geert Uytterhoeven

bitops: move find_bit_*_le functions from le.h to find.h

2022-01-15T16:47:30Z

It's convenient to have all find_bit declarations in one place. Signed-off-by: Yury Norov Tested-by: Wolfram Sang

bitops: protect find_first_{,zero}_bit properly

2022-01-15T16:47:30Z

find_first_bit() and find_first_zero_bit() are not protected with ifdefs as other functions in find.h. It causes build errors on some platforms if CONFIG_GENERIC_FIND_FIRST_BIT is enabled. Signed-off-by: Yury Norov Fixes: 2cc7b6a44ac2 ("lib: add fast path for find_first_*_bit() and find_last_bit()") Reported-by: kernel test robot Tested-by: Wolfram Sang

asm-generic/bitops, kcsan: Add instrumentation for barriers

2021-12-10T00:42:28Z

Adds the required KCSAN instrumentation for barriers of atomic bitops. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

Merge tag 'asm-generic-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

2021-09-01T22:13:02Z

Pull asm-generic updates from Arnd Bergmann: "The main content for 5.15 is a series that cleans up the handling of strncpy_from_user() and strnlen_user(), removing a lot of slightly incorrect versions of these in favor of the lib/strn*.c helpers that implement these correctly and more efficiently. The only architectures that retain a private version now are mips, ia64, um and parisc. I had offered to convert those at all, but Thomas Bogendoerfer wanted to keep the mips version for the moment until he had a chance to do regression testing. The branch also contains two patches for bitops and for ffs()" * tag 'asm-generic-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic: bitops/non-atomic: make @nr unsigned to avoid any DIV asm-generic: ffs: Drop bogus reference to ffz location asm-generic: reverse GENERIC_{STRNCPY_FROM,STRNLEN}_USER symbols asm-generic: remove extra strn{cpy_from,len}_user declarations asm-generic: uaccess: remove inline strncpy_from_user/strnlen_user s390: use generic strncpy/strnlen from_user microblaze: use generic strncpy/strnlen from_user csky: use generic strncpy/strnlen from_user arc: use generic strncpy/strnlen from_user hexagon: use generic strncpy/strnlen from_user h8300: remove stale strncpy_from_user asm-generic/uaccess.h: remove __strncpy_from_user/__strnlen_user

bitops/non-atomic: make @nr unsigned to avoid any DIV

2021-08-14T11:07:42Z

signed math causes generation of costlier instructions such as DIV when they could be done by barrerl shifter. Worse part is this is not caught by things like bloat-o-meter since instruction length / symbols are typically same size. e.g. stock (signed math) __________________ 919b4614 : 919b4614: div r2,r0,0x20 ^^^ 919b4618: add2 r2,0x920f6050,r2 919b4620: ld_s r2,[r2,0] 919b4622: lsr r0,r2,r0 919b4626: j_s.d [blink] 919b4628: bmsk_s r0,r0,0 919b462a: nop_s (patched) unsigned math __________________ 919b4614 : 919b4614: lsr r2,r0,0x5 @nr/32 ^^^ 919b4618: add2 r2,0x920f6050,r2 919b4620: ld_s r2,[r2,0] 919b4622: lsr r0,r2,r0 #test_bit() 919b4626: j_s.d [blink] 919b4628: bmsk_s r0,r0,0 919b462a: nop_s Signed-off-by: Vineet Gupta Acked-by: Will Deacon Signed-off-by: Arnd Bergmann

asm-generic: ffs: Drop bogus reference to ffz location

2021-08-11T09:38:10Z

The generic definition of ffz() is not defined in the same header files as the generic definitions of ffs(). Signed-off-by: Geert Uytterhoeven Signed-off-by: Arnd Bergmann