diff options
Diffstat (limited to 'include/asm-x86/spinlock_64.h')
| -rw-r--r-- | include/asm-x86/spinlock_64.h | 37 |
1 files changed, 24 insertions, 13 deletions
diff --git a/include/asm-x86/spinlock_64.h b/include/asm-x86/spinlock_64.h index 88bf981e73c..3b5adf92ad0 100644 --- a/include/asm-x86/spinlock_64.h +++ b/include/asm-x86/spinlock_64.h @@ -33,14 +33,21 @@ static inline void __raw_spin_lock(raw_spinlock_t *lock) "cmpl $0,%0\n\t" "jle 3b\n\t" "jmp 1b\n" - "2:\t" : "=m" (lock->slock) : : "memory"); + "2:\t" + : "=m" (lock->slock) : : "memory"); } /* - * Same as __raw_spin_lock, but reenable interrupts during spinning. + * It is easier for the lock validator if interrupts are not re-enabled + * in the middle of a lock-acquire. This is a performance feature anyway + * so we turn it off: + * + * NOTE: there's an irqs-on section here, which normally would have to be + * irq-traced, but on CONFIG_TRACE_IRQFLAGS we never use this variant. */ #ifndef CONFIG_PROVE_LOCKING -static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags) +static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, + unsigned long flags) { asm volatile( "\n1:\t" @@ -48,12 +55,12 @@ static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long fla "jns 5f\n" "testl $0x200, %1\n\t" /* interrupts were disabled? */ "jz 4f\n\t" - "sti\n" + STI_STRING "\n" "3:\t" "rep;nop\n\t" "cmpl $0, %0\n\t" "jle 3b\n\t" - "cli\n\t" + CLI_STRING "\n\t" "jmp 1b\n" "4:\t" "rep;nop\n\t" @@ -61,7 +68,9 @@ static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long fla "jg 1b\n\t" "jmp 4b\n" "5:\n\t" - : "+m" (lock->slock) : "r" ((unsigned)flags) : "memory"); + : "+m" (lock->slock) + : "r" ((unsigned)flags) CLI_STI_INPUT_ARGS + : "memory" CLI_STI_CLOBBERS); } #endif @@ -79,7 +88,7 @@ static inline int __raw_spin_trylock(raw_spinlock_t *lock) static inline void __raw_spin_unlock(raw_spinlock_t *lock) { - asm volatile("movl $1,%0" :"=m" (lock->slock) :: "memory"); + asm volatile("movl $1,%0" : "=m" (lock->slock) :: "memory"); } static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock) @@ -114,18 +123,18 @@ static inline int __raw_write_can_lock(raw_rwlock_t *lock) static inline void __raw_read_lock(raw_rwlock_t *rw) { - asm volatile(LOCK_PREFIX "subl $1,(%0)\n\t" + asm volatile(LOCK_PREFIX " subl $1,(%0)\n\t" "jns 1f\n" - "call __read_lock_failed\n" + "call __read_lock_failed\n\t" "1:\n" ::"D" (rw), "i" (RW_LOCK_BIAS) : "memory"); } static inline void __raw_write_lock(raw_rwlock_t *rw) { - asm volatile(LOCK_PREFIX "subl %1,(%0)\n\t" + asm volatile(LOCK_PREFIX " subl %1,(%0)\n\t" "jz 1f\n" - "\tcall __write_lock_failed\n\t" + "call __write_lock_failed\n\t" "1:\n" ::"D" (rw), "i" (RW_LOCK_BIAS) : "memory"); } @@ -133,6 +142,7 @@ static inline void __raw_write_lock(raw_rwlock_t *rw) static inline int __raw_read_trylock(raw_rwlock_t *lock) { atomic_t *count = (atomic_t *)lock; + atomic_dec(count); if (atomic_read(count) >= 0) return 1; @@ -143,6 +153,7 @@ static inline int __raw_read_trylock(raw_rwlock_t *lock) static inline int __raw_write_trylock(raw_rwlock_t *lock) { atomic_t *count = (atomic_t *)lock; + if (atomic_sub_and_test(RW_LOCK_BIAS, count)) return 1; atomic_add(RW_LOCK_BIAS, count); @@ -151,12 +162,12 @@ static inline int __raw_write_trylock(raw_rwlock_t *lock) static inline void __raw_read_unlock(raw_rwlock_t *rw) { - asm volatile(LOCK_PREFIX " ; incl %0" :"=m" (rw->lock) : : "memory"); + asm volatile(LOCK_PREFIX "incl %0" :"=m" (rw->lock) : : "memory"); } static inline void __raw_write_unlock(raw_rwlock_t *rw) { - asm volatile(LOCK_PREFIX " ; addl $" RW_LOCK_BIAS_STR ",%0" + asm volatile(LOCK_PREFIX "addl $" RW_LOCK_BIAS_STR ",%0" : "=m" (rw->lock) : : "memory"); } |