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| author | Mark Rutland <mark.rutland@arm.com> | 2026-09-08 16:17:23 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2026-09-11 12:32:22 +0000 |
| commit | 8cf2093f5372952a9ebc805c418d45df7112cd14 (patch) | |
| tree | 39be4b8d73b2e9b92623c9665434fa1815007fa4 /arch | |
| parent | 44274c657256b4911de82f8104e9e22f054cf742 (diff) | |
| download | linux-next-8cf2093f5372952a9ebc805c418d45df7112cd14.tar.gz linux-next-8cf2093f5372952a9ebc805c418d45df7112cd14.zip | |
arm64: percpu: Fix LSE operations on {8,16}-bit types
The assembly for __percpu_##name##_case_##sz() and
__percpu_##name##_return_case_##sz() doesn't use the 'sfx' macro
argument to form the LSE instruction. Without 'sfx', a W register
argument will imply a 32-bit memory location, and consequently
{8,16}-bit ops will erroneously read and write 32 bits of memory when
the LSE instruction is used.
Fix this by appending 'sfx' to 'op_lse' to LSE instruction. It is not
necessary (and not valid) to append 'sfx' to 'op_llsc', as 'op_llsc' is
a register-register operation which does not access memory (and does not
take a size suffix).
Fixes: 959bf2fd03b5 ("arm64: percpu: Rewrite per-cpu ops to allow use of LSE atomics")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Jinjie Ruan <ruanjinjie@huawei.com>
Cc: Ada Couprie Diaz <ada.coupriediaz@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vladimir Murzin <vladimir.murzin@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
Cc: stable@vger.kernel.org
Reviewed-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/include/asm/percpu.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/percpu.h b/arch/arm64/include/asm/percpu.h index 31193bcf89a2..8cf4068ce1b5 100644 --- a/arch/arm64/include/asm/percpu.h +++ b/arch/arm64/include/asm/percpu.h @@ -77,7 +77,7 @@ __percpu_##name##_case_##sz(void *ptr, unsigned long val) \ " stxr" #sfx "\t%w[loop], %" #w "[tmp], %[ptr]\n" \ " cbnz %w[loop], 1b", \ /* LSE atomics */ \ - #op_lse "\t%" #w "[val], %" #w "[tmp], %[ptr]\n" \ + #op_lse #sfx "\t%" #w "[val], %" #w "[tmp], %[ptr]\n" \ __nops(3)) \ : [loop] "=&r" (loop), [tmp] "=&r" (tmp), \ [ptr] "+Q"(*(u##sz *)ptr) \ @@ -98,7 +98,7 @@ __percpu_##name##_return_case_##sz(void *ptr, unsigned long val) \ " stxr" #sfx "\t%w[loop], %" #w "[ret], %[ptr]\n" \ " cbnz %w[loop], 1b", \ /* LSE atomics */ \ - #op_lse "\t%" #w "[val], %" #w "[ret], %[ptr]\n" \ + #op_lse #sfx "\t%" #w "[val], %" #w "[ret], %[ptr]\n" \ #op_llsc "\t%" #w "[ret], %" #w "[ret], %" #w "[val]\n" \ __nops(2)) \ : [loop] "=&r" (loop), [ret] "=&r" (ret), \ |