diff options
Diffstat (limited to 'arch/arm64/include/asm/spinlock.h')
| -rw-r--r-- | arch/arm64/include/asm/spinlock.h | 37 |
1 files changed, 21 insertions, 16 deletions
diff --git a/arch/arm64/include/asm/spinlock.h b/arch/arm64/include/asm/spinlock.h index e875a5a551d7..cae331d553f8 100644 --- a/arch/arm64/include/asm/spinlock.h +++ b/arch/arm64/include/asm/spinlock.h @@ -66,8 +66,7 @@ static inline void arch_spin_unlock_wait(arch_spinlock_t *lock) ARM64_LSE_ATOMIC_INSN( /* LL/SC */ " stxr %w1, %w0, %2\n" -" nop\n" -" nop\n", + __nops(2), /* LSE atomics */ " mov %w1, %w0\n" " cas %w0, %w0, %2\n" @@ -99,9 +98,7 @@ static inline void arch_spin_lock(arch_spinlock_t *lock) /* LSE atomics */ " mov %w2, %w5\n" " ldadda %w2, %w0, %3\n" -" nop\n" -" nop\n" -" nop\n" + __nops(3) ) /* Did we get the lock? */ @@ -165,8 +162,8 @@ static inline void arch_spin_unlock(arch_spinlock_t *lock) " stlrh %w1, %0", /* LSE atomics */ " mov %w1, #1\n" - " nop\n" - " staddlh %w1, %0") + " staddlh %w1, %0\n" + __nops(1)) : "=Q" (lock->owner), "=&r" (tmp) : : "memory"); @@ -212,7 +209,7 @@ static inline void arch_write_lock(arch_rwlock_t *rw) " cbnz %w0, 1b\n" " stxr %w0, %w2, %1\n" " cbnz %w0, 2b\n" - " nop", + __nops(1), /* LSE atomics */ "1: mov %w0, wzr\n" "2: casa %w0, %w2, %1\n" @@ -241,8 +238,7 @@ static inline int arch_write_trylock(arch_rwlock_t *rw) /* LSE atomics */ " mov %w0, wzr\n" " casa %w0, %w2, %1\n" - " nop\n" - " nop") + __nops(2)) : "=&r" (tmp), "+Q" (rw->lock) : "r" (0x80000000) : "memory"); @@ -290,8 +286,8 @@ static inline void arch_read_lock(arch_rwlock_t *rw) " add %w0, %w0, #1\n" " tbnz %w0, #31, 1b\n" " stxr %w1, %w0, %2\n" - " nop\n" - " cbnz %w1, 2b", + " cbnz %w1, 2b\n" + __nops(1), /* LSE atomics */ "1: wfe\n" "2: ldxr %w0, %2\n" @@ -317,9 +313,8 @@ static inline void arch_read_unlock(arch_rwlock_t *rw) " cbnz %w1, 1b", /* LSE atomics */ " movn %w0, #0\n" - " nop\n" - " nop\n" - " staddl %w0, %2") + " staddl %w0, %2\n" + __nops(2)) : "=&r" (tmp), "=&r" (tmp2), "+Q" (rw->lock) : : "memory"); @@ -344,7 +339,7 @@ static inline int arch_read_trylock(arch_rwlock_t *rw) " tbnz %w1, #31, 1f\n" " casa %w0, %w1, %2\n" " sbc %w1, %w1, %w0\n" - " nop\n" + __nops(1) "1:") : "=&r" (tmp), "=&r" (tmp2), "+Q" (rw->lock) : @@ -363,4 +358,14 @@ static inline int arch_read_trylock(arch_rwlock_t *rw) #define arch_read_relax(lock) cpu_relax() #define arch_write_relax(lock) cpu_relax() +/* + * Accesses appearing in program order before a spin_lock() operation + * can be reordered with accesses inside the critical section, by virtue + * of arch_spin_lock being constructed using acquire semantics. + * + * In cases where this is problematic (e.g. try_to_wake_up), an + * smp_mb__before_spinlock() can restore the required ordering. + */ +#define smp_mb__before_spinlock() smp_mb() + #endif /* __ASM_SPINLOCK_H */ |
