diff options
| author | Kees Cook <keescook@chromium.org> | 2022-01-12 12:22:59 -0800 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2022-01-20 09:13:48 +0000 |
| commit | 3364c6ce23c6e347c63fc895e0d6d1e8a9407849 (patch) | |
| tree | 913d3bc6c1fc6de38e830453309bf637b1b1a4cd | |
| parent | 440323b6cf5b9896013a78c4f578823e8243a7fd (diff) | |
arm64: atomics: lse: Dereference matching size
When building with -Warray-bounds, the following warning is generated:
In file included from ./arch/arm64/include/asm/lse.h:16,
from ./arch/arm64/include/asm/cmpxchg.h:14,
from ./arch/arm64/include/asm/atomic.h:16,
from ./include/linux/atomic.h:7,
from ./include/asm-generic/bitops/atomic.h:5,
from ./arch/arm64/include/asm/bitops.h:25,
from ./include/linux/bitops.h:33,
from ./include/linux/kernel.h:22,
from kernel/printk/printk.c:22:
./arch/arm64/include/asm/atomic_lse.h:247:9: warning: array subscript 'long unsigned int[0]' is partly outside array bounds of 'atomic_t[1]' [-Warray-bounds]
247 | asm volatile( \
| ^~~
./arch/arm64/include/asm/atomic_lse.h:266:1: note: in expansion of macro '__CMPXCHG_CASE'
266 | __CMPXCHG_CASE(w, , acq_, 32, a, "memory")
| ^~~~~~~~~~~~~~
kernel/printk/printk.c:3606:17: note: while referencing 'printk_cpulock_owner'
3606 | static atomic_t printk_cpulock_owner = ATOMIC_INIT(-1);
| ^~~~~~~~~~~~~~~~~~~~
This is due to the compiler seeing an unsigned long * cast against
something (atomic_t) that is int sized. Replace the cast with the
matching size cast. This results in no change in binary output.
Note that __ll_sc__cmpxchg_case_##name##sz already uses the same
constraint:
[v] "+Q" (*(u##sz *)ptr
Which is why only the LSE form needs updating and not the
LL/SC form, so this change is unlikely to be problematic.
Cc: Will Deacon <will@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220112202259.3950286-1-keescook@chromium.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| -rw-r--r-- | arch/arm64/include/asm/atomic_lse.h | 2 | ||||
| -rw-r--r-- | arch/arm64/include/asm/cmpxchg.h | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/atomic_lse.h b/arch/arm64/include/asm/atomic_lse.h index d955ade5df7c..5d460f6b7675 100644 --- a/arch/arm64/include/asm/atomic_lse.h +++ b/arch/arm64/include/asm/atomic_lse.h @@ -249,7 +249,7 @@ __lse__cmpxchg_case_##name##sz(volatile void *ptr, \ " mov %" #w "[tmp], %" #w "[old]\n" \ " cas" #mb #sfx "\t%" #w "[tmp], %" #w "[new], %[v]\n" \ " mov %" #w "[ret], %" #w "[tmp]" \ - : [ret] "+r" (x0), [v] "+Q" (*(unsigned long *)ptr), \ + : [ret] "+r" (x0), [v] "+Q" (*(u##sz *)ptr), \ [tmp] "=&r" (tmp) \ : [old] "r" (x1), [new] "r" (x2) \ : cl); \ diff --git a/arch/arm64/include/asm/cmpxchg.h b/arch/arm64/include/asm/cmpxchg.h index f9bef42c1411..497acf134d99 100644 --- a/arch/arm64/include/asm/cmpxchg.h +++ b/arch/arm64/include/asm/cmpxchg.h @@ -243,7 +243,7 @@ static inline void __cmpwait_case_##sz(volatile void *ptr, \ " cbnz %" #w "[tmp], 1f\n" \ " wfe\n" \ "1:" \ - : [tmp] "=&r" (tmp), [v] "+Q" (*(unsigned long *)ptr) \ + : [tmp] "=&r" (tmp), [v] "+Q" (*(u##sz *)ptr) \ : [val] "r" (val)); \ } |