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| author | H. Peter Anvin <hpa@zytor.com> | 2016-06-08 21:38:38 +0200 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2016-06-08 21:41:20 +0200 |
| commit | 117780eef7740729e803bdcc0d5f2f48137ea8e3 (patch) | |
| tree | 63bd519e1d8b115d332fcb6e63ee4f94ee235161 /arch/x86/include/asm/rwsem.h | |
| parent | x86, bitops: remove use of "sbb" to return CF (diff) | |
| download | linux-117780eef7740729e803bdcc0d5f2f48137ea8e3.tar.xz linux-117780eef7740729e803bdcc0d5f2f48137ea8e3.zip | |
x86, asm: use bool for bitops and other assembly outputs
The gcc people have confirmed that using "bool" when combined with
inline assembly always is treated as a byte-sized operand that can be
assumed to be 0 or 1, which is exactly what the SET instruction
emits. Change the output types and intermediate variables of as many
operations as practical to "bool".
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1465414726-197858-3-git-send-email-hpa@linux.intel.com
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Diffstat (limited to 'arch/x86/include/asm/rwsem.h')
| -rw-r--r-- | arch/x86/include/asm/rwsem.h | 17 |
1 files changed, 9 insertions, 8 deletions
diff --git a/arch/x86/include/asm/rwsem.h b/arch/x86/include/asm/rwsem.h index 453744c1d347..c5087706c02e 100644 --- a/arch/x86/include/asm/rwsem.h +++ b/arch/x86/include/asm/rwsem.h @@ -77,7 +77,7 @@ static inline void __down_read(struct rw_semaphore *sem) /* * trylock for reading -- returns 1 if successful, 0 if contention */ -static inline int __down_read_trylock(struct rw_semaphore *sem) +static inline bool __down_read_trylock(struct rw_semaphore *sem) { long result, tmp; asm volatile("# beginning __down_read_trylock\n\t" @@ -93,7 +93,7 @@ static inline int __down_read_trylock(struct rw_semaphore *sem) : "+m" (sem->count), "=&a" (result), "=&r" (tmp) : "i" (RWSEM_ACTIVE_READ_BIAS) : "memory", "cc"); - return result >= 0 ? 1 : 0; + return result >= 0; } /* @@ -134,9 +134,10 @@ static inline int __down_write_killable(struct rw_semaphore *sem) /* * trylock for writing -- returns 1 if successful, 0 if contention */ -static inline int __down_write_trylock(struct rw_semaphore *sem) +static inline bool __down_write_trylock(struct rw_semaphore *sem) { - long result, tmp; + bool result; + long tmp0, tmp1; asm volatile("# beginning __down_write_trylock\n\t" " mov %0,%1\n\t" "1:\n\t" @@ -144,14 +145,14 @@ static inline int __down_write_trylock(struct rw_semaphore *sem) /* was the active mask 0 before? */ " jnz 2f\n\t" " mov %1,%2\n\t" - " add %3,%2\n\t" + " add %4,%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" + " sete %3\n\t" "# ending __down_write_trylock\n\t" - : "+m" (sem->count), "=&a" (result), "=&r" (tmp) + : "+m" (sem->count), "=&a" (tmp0), "=&r" (tmp1), + "=qm" (result) : "er" (RWSEM_ACTIVE_WRITE_BIAS) : "memory", "cc"); return result; |