[PATCH] x86, asm: Use named operands in rwsem.h
From: Miguel Bernal Marin
Date: Mon Sep 25 2017 - 19:04:23 EST
Since GCC version 3.1, it is possible to specify input and output
operands using symbolic names which can be referenced within the
assembler code.
Convert to named operands makes easy to understand and maintain for
future changes. This commit update operands in asm/rwsem.h.
Signed-off-by: Miguel Bernal Marin <miguel.bernal.marin@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/rwsem.h | 53 ++++++++++++++++++++++----------------------
1 file changed, 27 insertions(+), 26 deletions(-)
diff --git a/arch/x86/include/asm/rwsem.h b/arch/x86/include/asm/rwsem.h
index 7116b7931c7b..a8f486e7a124 100644
--- a/arch/x86/include/asm/rwsem.h
+++ b/arch/x86/include/asm/rwsem.h
@@ -63,14 +63,14 @@
static inline void __down_read(struct rw_semaphore *sem)
{
asm volatile("# beginning down_read\n\t"
- LOCK_PREFIX _ASM_INC "(%1)\n\t"
+ LOCK_PREFIX _ASM_INC "(%[sem])\n\t"
/* adds 0x00000001 */
" jns 1f\n"
" call call_rwsem_down_read_failed\n"
"1:\n\t"
"# ending down_read\n\t"
: "+m" (sem->count)
- : "a" (sem)
+ : [sem] "a" (sem)
: "memory", "cc");
}
@@ -81,17 +81,18 @@ static inline bool __down_read_trylock(struct rw_semaphore *sem)
{
long result, tmp;
asm volatile("# beginning __down_read_trylock\n\t"
- " mov %0,%1\n\t"
+ " mov %[count],%[result]\n\t"
"1:\n\t"
- " mov %1,%2\n\t"
- " add %3,%2\n\t"
+ " mov %[result],%[tmp]\n\t"
+ " add %[inc],%[tmp]\n\t"
" jle 2f\n\t"
- LOCK_PREFIX " cmpxchg %2,%0\n\t"
+ LOCK_PREFIX " cmpxchg %[tmp],%[count]\n\t"
" jnz 1b\n\t"
"2:\n\t"
"# ending __down_read_trylock\n\t"
- : "+m" (sem->count), "=&a" (result), "=&r" (tmp)
- : "i" (RWSEM_ACTIVE_READ_BIAS)
+ : [count] "+m" (sem->count), [result] "=&a" (result),
+ [tmp] "=&r" (tmp)
+ : [inc] "i" (RWSEM_ACTIVE_READ_BIAS)
: "memory", "cc");
return result >= 0;
}
@@ -105,7 +106,7 @@ static inline bool __down_read_trylock(struct rw_semaphore *sem)
struct rw_semaphore* ret; \
\
asm volatile("# beginning down_write\n\t" \
- LOCK_PREFIX " xadd %1,(%4)\n\t" \
+ LOCK_PREFIX " xadd %[tmp],(%[sem])\n\t" \
/* adds 0xffff0001, returns the old value */ \
" test " __ASM_SEL(%w1,%k1) "," __ASM_SEL(%w1,%k1) "\n\t" \
/* was the active mask 0 before? */\
@@ -113,9 +114,9 @@ static inline bool __down_read_trylock(struct rw_semaphore *sem)
" call " slow_path "\n" \
"1:\n" \
"# ending down_write" \
- : "+m" (sem->count), "=d" (tmp), \
+ : "+m" (sem->count), [tmp] "=d" (tmp), \
"=a" (ret), ASM_CALL_CONSTRAINT \
- : "a" (sem), "1" (RWSEM_ACTIVE_WRITE_BIAS) \
+ : [sem] "a" (sem), "[tmp]" (RWSEM_ACTIVE_WRITE_BIAS) \
: "memory", "cc"); \
ret; \
})
@@ -141,21 +142,21 @@ static inline bool __down_write_trylock(struct rw_semaphore *sem)
bool result;
long tmp0, tmp1;
asm volatile("# beginning __down_write_trylock\n\t"
- " mov %0,%1\n\t"
+ " mov %[count],%[tmp0]\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 %4,%2\n\t"
- LOCK_PREFIX " cmpxchg %2,%0\n\t"
+ " mov %[tmp0],%[tmp1]\n\t"
+ " add %[inc],%[tmp1]\n\t"
+ LOCK_PREFIX " cmpxchg %[tmp1],%[count]\n\t"
" jnz 1b\n\t"
"2:\n\t"
CC_SET(e)
"# ending __down_write_trylock\n\t"
- : "+m" (sem->count), "=&a" (tmp0), "=&r" (tmp1),
- CC_OUT(e) (result)
- : "er" (RWSEM_ACTIVE_WRITE_BIAS)
+ : [count] "+m" (sem->count), [tmp0] "=&a" (tmp0),
+ [tmp1] "=&r" (tmp1), CC_OUT(e) (result)
+ : [inc] "er" (RWSEM_ACTIVE_WRITE_BIAS)
: "memory");
return result;
}
@@ -167,14 +168,14 @@ static inline void __up_read(struct rw_semaphore *sem)
{
long tmp;
asm volatile("# beginning __up_read\n\t"
- LOCK_PREFIX " xadd %1,(%2)\n\t"
+ LOCK_PREFIX " xadd %[tmp],(%[sem])\n\t"
/* subtracts 1, returns the old value */
" jns 1f\n\t"
" call call_rwsem_wake\n" /* expects old value in %edx */
"1:\n"
"# ending __up_read\n"
- : "+m" (sem->count), "=d" (tmp)
- : "a" (sem), "1" (-RWSEM_ACTIVE_READ_BIAS)
+ : "+m" (sem->count), [tmp] "=d" (tmp)
+ : [sem] "a" (sem), "[tmp]" (-RWSEM_ACTIVE_READ_BIAS)
: "memory", "cc");
}
@@ -185,14 +186,14 @@ static inline void __up_write(struct rw_semaphore *sem)
{
long tmp;
asm volatile("# beginning __up_write\n\t"
- LOCK_PREFIX " xadd %1,(%2)\n\t"
+ LOCK_PREFIX " xadd %[tmp],(%[sem])\n\t"
/* subtracts 0xffff0001, returns the old value */
" jns 1f\n\t"
" call call_rwsem_wake\n" /* expects old value in %edx */
"1:\n\t"
"# ending __up_write\n"
- : "+m" (sem->count), "=d" (tmp)
- : "a" (sem), "1" (-RWSEM_ACTIVE_WRITE_BIAS)
+ : "+m" (sem->count), [tmp] "=d" (tmp)
+ : [sem] "a" (sem), "[tmp]" (-RWSEM_ACTIVE_WRITE_BIAS)
: "memory", "cc");
}
@@ -202,7 +203,7 @@ static inline void __up_write(struct rw_semaphore *sem)
static inline void __downgrade_write(struct rw_semaphore *sem)
{
asm volatile("# beginning __downgrade_write\n\t"
- LOCK_PREFIX _ASM_ADD "%2,(%1)\n\t"
+ LOCK_PREFIX _ASM_ADD "%[inc],(%[sem])\n\t"
/*
* transitions 0xZZZZ0001 -> 0xYYYY0001 (i386)
* 0xZZZZZZZZ00000001 -> 0xYYYYYYYY00000001 (x86_64)
@@ -212,7 +213,7 @@ static inline void __downgrade_write(struct rw_semaphore *sem)
"1:\n\t"
"# ending __downgrade_write\n"
: "+m" (sem->count)
- : "a" (sem), "er" (-RWSEM_WAITING_BIAS)
+ : [sem] "a" (sem), [inc] "er" (-RWSEM_WAITING_BIAS)
: "memory", "cc");
}
--
2.14.1