mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-12-15 08:20:16 +08:00
Adjust TAS assembly as per recent discussions: use "+m"(*lock) everywhere
to reference the spinlock variable, and specify "memory" as a clobber operand to be sure gcc does not try to keep shared-memory values in registers across a spinlock acquisition. Also tighten the S/390 asm sequence, which was apparently written with only minimal study of the gcc asm documentation. I have personally tested i386, ia64, ppc, hppa, and s390 variants --- there is some small chance that I broke the others, but I doubt it.
This commit is contained in:
Tom Lane
parent
c1d9dec3e3
commit
1098677482
@ -66,7 +66,7 @@
|
||||
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
|
||||
* Portions Copyright (c) 1994, Regents of the University of California
|
||||
*
|
||||
* $PostgreSQL: pgsql/src/include/storage/s_lock.h,v 1.125 2004/01/03 05:47:44 tgl Exp $
|
||||
* $PostgreSQL: pgsql/src/include/storage/s_lock.h,v 1.126 2004/06/19 23:02:32 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
@ -85,16 +85,26 @@
|
||||
* Other compilers use __cpu or __cpu__ so we test for both in those cases.
|
||||
*/
|
||||
|
||||
/*
|
||||
* Standard gcc asm format is:
|
||||
*
|
||||
/*----------
|
||||
* Standard gcc asm format (assuming "volatile slock_t *lock"):
|
||||
|
||||
__asm__ __volatile__(
|
||||
" command \n"
|
||||
" command \n"
|
||||
" command \n"
|
||||
: "=r"(_res) return value, in register
|
||||
: "r"(lock) argument, 'lock pointer', in register
|
||||
: "r0"); inline code uses this register
|
||||
" instruction \n"
|
||||
" instruction \n"
|
||||
" instruction \n"
|
||||
: "=r"(_res), "+m"(*lock) // return register, in/out lock value
|
||||
: "r"(lock) // lock pointer, in input register
|
||||
: "memory", "cc"); // show clobbered registers here
|
||||
|
||||
* The output-operands list (after first colon) should always include
|
||||
* "+m"(*lock), whether or not the asm code actually refers to this
|
||||
* operand directly. This ensures that gcc believes the value in the
|
||||
* lock variable is used and set by the asm code. Also, the clobbers
|
||||
* list (after third colon) should always include "memory"; this prevents
|
||||
* gcc from thinking it can cache the values of shared-memory fields
|
||||
* across the asm code. Add "cc" if your asm code changes the condition
|
||||
* code register, and also list any temp registers the code uses.
|
||||
*----------
|
||||
*/
|
||||
|
||||
|
||||
@ -117,8 +127,9 @@ tas(volatile slock_t *lock)
|
||||
" lock \n"
|
||||
" xchgb %0,%1 \n"
|
||||
"1: \n"
|
||||
: "=q"(_res), "=m"(*lock)
|
||||
: "0"(_res));
|
||||
: "+q"(_res), "+m"(*lock)
|
||||
:
|
||||
: "memory", "cc");
|
||||
return (int) _res;
|
||||
}
|
||||
|
||||
@ -128,8 +139,7 @@ static __inline__ void
|
||||
spin_delay(void)
|
||||
{
|
||||
__asm__ __volatile__(
|
||||
" rep; nop \n"
|
||||
: : : "memory");
|
||||
" rep; nop \n");
|
||||
}
|
||||
|
||||
#endif /* __i386__ || __x86_64__ */
|
||||
@ -150,10 +160,9 @@ tas(volatile slock_t *lock)
|
||||
|
||||
__asm__ __volatile__(
|
||||
" xchg4 %0=%1,%2 \n"
|
||||
: "=r"(ret), "=m"(*lock)
|
||||
: "r"(1), "1"(*lock)
|
||||
: "=r"(ret), "+m"(*lock)
|
||||
: "r"(1)
|
||||
: "memory");
|
||||
|
||||
return (int) ret;
|
||||
}
|
||||
|
||||
@ -173,17 +182,18 @@ tas(volatile slock_t *lock)
|
||||
register slock_t _res = 1;
|
||||
|
||||
__asm__ __volatile__(
|
||||
" swpb %0, %0, [%3] \n"
|
||||
: "=r"(_res), "=m"(*lock)
|
||||
: "0"(_res), "r"(lock));
|
||||
" swpb %0, %0, [%2] \n"
|
||||
: "+r"(_res), "+m"(*lock)
|
||||
: "r"(lock)
|
||||
: "memory");
|
||||
return (int) _res;
|
||||
}
|
||||
|
||||
#endif /* __arm__ */
|
||||
|
||||
|
||||
#if defined(__s390__) && !defined(__s390x__)
|
||||
/* S/390 Linux */
|
||||
#if defined(__s390__) || defined(__s390x__)
|
||||
/* S/390 and S/390x Linux (32- and 64-bit zSeries) */
|
||||
#define HAS_TEST_AND_SET
|
||||
|
||||
typedef unsigned int slock_t;
|
||||
@ -193,51 +203,17 @@ typedef unsigned int slock_t;
|
||||
static __inline__ int
|
||||
tas(volatile slock_t *lock)
|
||||
{
|
||||
int _res;
|
||||
int _res = 0;
|
||||
|
||||
__asm__ __volatile__(
|
||||
" la 1,1 \n"
|
||||
" l 2,%2 \n"
|
||||
" slr 0,0 \n"
|
||||
" cs 0,1,0(2) \n"
|
||||
" lr %1,0 \n"
|
||||
: "=m"(lock), "=d"(_res)
|
||||
: "m"(lock)
|
||||
: "0", "1", "2");
|
||||
|
||||
return (_res);
|
||||
" cs %0,%3,0(%2) \n"
|
||||
: "+d"(_res), "+m"(*lock)
|
||||
: "a"(lock), "d"(1)
|
||||
: "memory", "cc");
|
||||
return _res;
|
||||
}
|
||||
|
||||
#endif /* __s390__ */
|
||||
|
||||
|
||||
#if defined(__s390x__)
|
||||
/* S/390x Linux (64-bit zSeries) */
|
||||
#define HAS_TEST_AND_SET
|
||||
|
||||
typedef unsigned int slock_t;
|
||||
|
||||
#define TAS(lock) tas(lock)
|
||||
|
||||
static __inline__ int
|
||||
tas(volatile slock_t *lock)
|
||||
{
|
||||
int _res;
|
||||
|
||||
__asm__ __volatile__(
|
||||
" la 1,1 \n"
|
||||
" lg 2,%2 \n"
|
||||
" slr 0,0 \n"
|
||||
" cs 0,1,0(2) \n"
|
||||
" lr %1,0 \n"
|
||||
: "=m"(lock), "=d"(_res)
|
||||
: "m"(lock)
|
||||
: "0", "1", "2");
|
||||
|
||||
return (_res);
|
||||
}
|
||||
|
||||
#endif /* __s390x__ */
|
||||
#endif /* __s390__ || __s390x__ */
|
||||
|
||||
|
||||
#if defined(__sparc__)
|
||||
@ -250,12 +226,13 @@ typedef unsigned char slock_t;
|
||||
static __inline__ int
|
||||
tas(volatile slock_t *lock)
|
||||
{
|
||||
register slock_t _res = 1;
|
||||
register slock_t _res;
|
||||
|
||||
__asm__ __volatile__(
|
||||
" ldstub [%2], %0 \n"
|
||||
: "=r"(_res), "=m"(*lock)
|
||||
: "r"(lock));
|
||||
: "=r"(_res), "+m"(*lock)
|
||||
: "r"(lock)
|
||||
: "memory");
|
||||
return (int) _res;
|
||||
}
|
||||
|
||||
@ -283,11 +260,11 @@ tas(volatile slock_t *lock)
|
||||
int _res;
|
||||
|
||||
__asm__ __volatile__(
|
||||
" lwarx %0,0,%2 \n"
|
||||
" lwarx %0,0,%3 \n"
|
||||
" cmpwi %0,0 \n"
|
||||
" bne 1f \n"
|
||||
" addi %0,%0,1 \n"
|
||||
" stwcx. %0,0,%2 \n"
|
||||
" stwcx. %0,0,%3 \n"
|
||||
" beq 2f \n"
|
||||
"1: li %1,1 \n"
|
||||
" b 3f \n"
|
||||
@ -296,10 +273,9 @@ tas(volatile slock_t *lock)
|
||||
" li %1,0 \n"
|
||||
"3: \n"
|
||||
|
||||
: "=&r" (_t), "=r" (_res)
|
||||
: "r" (lock)
|
||||
: "cc", "memory"
|
||||
);
|
||||
: "=&r"(_t), "=r"(_res), "+m"(*lock)
|
||||
: "r"(lock)
|
||||
: "memory", "cc");
|
||||
return _res;
|
||||
}
|
||||
|
||||
@ -330,10 +306,9 @@ tas(volatile slock_t *lock)
|
||||
" clrl %0 \n"
|
||||
" tas %1 \n"
|
||||
" sne %0 \n"
|
||||
: "=d"(rv), "=m"(*lock)
|
||||
: "1"(*lock)
|
||||
: "cc");
|
||||
|
||||
: "=d"(rv), "+m"(*lock)
|
||||
:
|
||||
: "memory", "cc");
|
||||
return rv;
|
||||
}
|
||||
|
||||
@ -357,13 +332,13 @@ tas(volatile slock_t *lock)
|
||||
register int _res;
|
||||
|
||||
__asm__ __volatile__(
|
||||
" movl $1, r0 \n"
|
||||
" bbssi $0, (%1), 1f \n"
|
||||
" clrl r0 \n"
|
||||
"1: movl r0, %0 \n"
|
||||
: "=r"(_res)
|
||||
" movl $1, %0 \n"
|
||||
" bbssi $0, (%2), 1f \n"
|
||||
" clrl %0 \n"
|
||||
"1: \n"
|
||||
: "=&r"(_res), "+m"(*lock)
|
||||
: "r"(lock)
|
||||
: "r0");
|
||||
: "memory");
|
||||
return _res;
|
||||
}
|
||||
|
||||
@ -383,9 +358,11 @@ tas(volatile slock_t *lock)
|
||||
register int _res;
|
||||
|
||||
__asm__ __volatile__(
|
||||
" sbitb 0, %0 \n"
|
||||
" sfsd %1 \n"
|
||||
: "=m"(*lock), "=r"(_res));
|
||||
" sbitb 0, %1 \n"
|
||||
" sfsd %0 \n"
|
||||
: "=r"(_res), "+m"(*lock)
|
||||
:
|
||||
: "memory");
|
||||
return _res;
|
||||
}
|
||||
|
||||
@ -404,12 +381,6 @@ tas(volatile slock_t *lock)
|
||||
typedef unsigned long slock_t;
|
||||
|
||||
#define TAS(lock) tas(lock)
|
||||
#define S_UNLOCK(lock) \
|
||||
do \
|
||||
{\
|
||||
__asm__ __volatile__ (" mb \n"); \
|
||||
*((volatile slock_t *) (lock)) = 0; \
|
||||
} while (0)
|
||||
|
||||
static __inline__ int
|
||||
tas(volatile slock_t *lock)
|
||||
@ -417,24 +388,30 @@ tas(volatile slock_t *lock)
|
||||
register slock_t _res;
|
||||
|
||||
__asm__ __volatile__(
|
||||
" ldq $0, %0 \n"
|
||||
" ldq $0, %1 \n"
|
||||
" bne $0, 2f \n"
|
||||
" ldq_l %1, %0 \n"
|
||||
" bne %1, 2f \n"
|
||||
" ldq_l %0, %1 \n"
|
||||
" bne %0, 2f \n"
|
||||
" mov 1, $0 \n"
|
||||
" stq_c $0, %0 \n"
|
||||
" stq_c $0, %1 \n"
|
||||
" beq $0, 2f \n"
|
||||
" mb \n"
|
||||
" br 3f \n"
|
||||
"2: mov 1, %1 \n"
|
||||
"2: mov 1, %0 \n"
|
||||
"3: \n"
|
||||
: "=m"(*lock), "=r"(_res)
|
||||
: "=&r"(_res), "+m"(*lock)
|
||||
:
|
||||
: "0");
|
||||
|
||||
: "memory", "0");
|
||||
return (int) _res;
|
||||
}
|
||||
|
||||
#define S_UNLOCK(lock) \
|
||||
do \
|
||||
{\
|
||||
__asm__ __volatile__ (" mb \n"); \
|
||||
*((volatile slock_t *) (lock)) = 0; \
|
||||
} while (0)
|
||||
|
||||
#endif /* __alpha || __alpha__ */
|
||||
|
||||
|
||||
@ -540,8 +517,9 @@ tas(volatile slock_t *lock)
|
||||
|
||||
__asm__ __volatile__(
|
||||
" ldcwx 0(0,%2),%0 \n"
|
||||
: "=r"(lockval), "=m"(*lockword)
|
||||
: "r"(lockword));
|
||||
: "=r"(lockval), "+m"(*lockword)
|
||||
: "r"(lockword)
|
||||
: "memory");
|
||||
return (lockval == 0);
|
||||
}
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user