diff options
| author | Catalin Marinas <catalin.marinas@arm.com> | 2013-05-31 16:30:58 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2013-06-07 17:58:31 +0100 |
| commit | 4ecf7ccb1973fd826456b6ab1e6dfafe9023c753 (patch) | |
| tree | 318c48fdfa422908da871d25d2e47903321aabe3 | |
| parent | ebd88367de80f9509bd30a09342d0a19c925b23e (diff) | |
arm64: spinlock: retry trylock operation if strex fails on free lock
An exclusive store instruction may fail for reasons other than lock
contention (e.g. a cache eviction during the critical section) so, in
line with other architectures using similar exclusive instructions
(alpha, mips, powerpc), retry the trylock operation if the lock appears
to be free but the strex reported failure.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Tony Thompson <anthony.thompson@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
| -rw-r--r-- | arch/arm64/include/asm/spinlock.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/spinlock.h b/arch/arm64/include/asm/spinlock.h index 7065e920149d..0defa0728a9b 100644 --- a/arch/arm64/include/asm/spinlock.h +++ b/arch/arm64/include/asm/spinlock.h @@ -59,9 +59,10 @@ static inline int arch_spin_trylock(arch_spinlock_t *lock) unsigned int tmp; asm volatile( - " ldaxr %w0, %1\n" + "2: ldaxr %w0, %1\n" " cbnz %w0, 1f\n" " stxr %w0, %w2, %1\n" + " cbnz %w0, 2b\n" "1:\n" : "=&r" (tmp), "+Q" (lock->lock) : "r" (1) |