diff options
Diffstat (limited to 'arch/x86/include/asm/rwsem.h')
| -rw-r--r-- | arch/x86/include/asm/rwsem.h | 28 |
1 files changed, 21 insertions, 7 deletions
diff --git a/arch/x86/include/asm/rwsem.h b/arch/x86/include/asm/rwsem.h index 2dbe4a721ce..cad82c9c2fd 100644 --- a/arch/x86/include/asm/rwsem.h +++ b/arch/x86/include/asm/rwsem.h @@ -105,8 +105,8 @@ static inline void __down_write_nested(struct rw_semaphore *sem, int subclass) asm volatile("# beginning down_write\n\t" LOCK_PREFIX " xadd %1,(%2)\n\t" /* adds 0xffff0001, returns the old value */ - " test %1,%1\n\t" - /* was the count 0 before? */ + " test " __ASM_SEL(%w1,%k1) "," __ASM_SEL(%w1,%k1) "\n\t" + /* was the active mask 0 before? */ " jz 1f\n" " call call_rwsem_down_write_failed\n" "1:\n" @@ -126,11 +126,25 @@ static inline void __down_write(struct rw_semaphore *sem) */ static inline int __down_write_trylock(struct rw_semaphore *sem) { - long ret = cmpxchg(&sem->count, RWSEM_UNLOCKED_VALUE, - RWSEM_ACTIVE_WRITE_BIAS); - if (ret == RWSEM_UNLOCKED_VALUE) - return 1; - return 0; + long result, tmp; + asm volatile("# beginning __down_write_trylock\n\t" + " mov %0,%1\n\t" + "1:\n\t" + " test " __ASM_SEL(%w1,%k1) "," __ASM_SEL(%w1,%k1) "\n\t" + /* was the active mask 0 before? */ + " jnz 2f\n\t" + " mov %1,%2\n\t" + " add %3,%2\n\t" + LOCK_PREFIX " cmpxchg %2,%0\n\t" + " jnz 1b\n\t" + "2:\n\t" + " sete %b1\n\t" + " movzbl %b1, %k1\n\t" + "# ending __down_write_trylock\n\t" + : "+m" (sem->count), "=&a" (result), "=&r" (tmp) + : "er" (RWSEM_ACTIVE_WRITE_BIAS) + : "memory", "cc"); + return result; } /* |