- 根目录:
- arch
- mips
- include
- asm
- cmpxchg.h
/*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2003, 06, 07 by Ralf Baechle (ralf@linux-mips.org)
*/
#ifndef __ASM_CMPXCHG_H
#define __ASM_CMPXCHG_H
#include <linux/bug.h>
#include <linux/irqflags.h>
#include <asm/compiler.h>
#include <asm/war.h>
static inline unsigned long __xchg_u32(volatile int * m, unsigned int val)
{
__u32 retval;
smp_mb__before_llsc();
if (kernel_uses_llsc && R10000_LLSC_WAR) {
unsigned long dummy;
__asm__ __volatile__(
" .set arch=r4000 \n"
"1: ll %0, %3 # xchg_u32 \n"
" .set mips0 \n"
" move %2, %z4 \n"
" .set arch=r4000 \n"
" sc %2, %1 \n"
" beqzl %2, 1b \n"
" .set mips0 \n"
: "=&r" (retval), "=" GCC_OFF_SMALL_ASM() (*m), "=&r" (dummy)
: GCC_OFF_SMALL_ASM() (*m), "Jr" (val)
: "memory");
} else if (kernel_uses_llsc) {
unsigned long dummy;
do {
__asm__ __volatile__(
" .set "MIPS_ISA_ARCH_LEVEL" \n"
" ll %0, %3 # xchg_u32 \n"
" .set mips0 \n"
" move %2, %z4 \n"
" .set "MIPS_ISA_ARCH_LEVEL" \n"
" sc %2, %1 \n"
" .set mips0 \n"
: "=&r" (retval), "=" GCC_OFF_SMALL_ASM() (*m),
"=&r" (dummy)
: GCC_OFF_SMALL_ASM() (*m), "Jr" (val)
: "memory");
} while (unlikely(!dummy));
} else {
unsigned long flags;
raw_local_irq_save(flags);
retval = *m;
*m = val;
raw_local_irq_restore(flags); /* implies memory barrier */
}
smp_llsc_mb();
return retval;
}
#ifdef CONFIG_64BIT
static inline __u64 __xchg_u64(volatile __u64 * m, __u64 val)
{
__u64 retval;
smp_mb__before_llsc();
if (kernel_uses_llsc && R10000_LLSC_WAR) {
unsigned long dummy;
__asm__ __volatile__(
" .set arch=r4000 \n"
"1: lld %0, %3 # xchg_u64 \n"
" move %2, %z4 \n"
" scd %2, %1 \n"
" beqzl %2, 1b \n"
" .set mips0 \n"
: "=&r" (retval), "=" GCC_OFF_SMALL_ASM() (*m), "=&r" (dummy)
: GCC_OFF_SMALL_ASM() (*m), "Jr" (val)
: "memory");
} else if (kernel_uses_llsc) {
unsigned long dummy;
do {
__asm__ __volatile__(
" .set "MIPS_ISA_ARCH_LEVEL" \n"
" lld %0, %3 # xchg_u64 \n"
" move %2, %z4 \n"
" scd %2, %1 \n"
" .set mips0 \n"
: "=&r" (retval), "=" GCC_OFF_SMALL_ASM() (*m),
"=&r" (dummy)
: GCC_OFF_SMALL_ASM() (*m), "Jr" (val)
: "memory");
} while (unlikely(!dummy));
} else {
unsigned long flags;
raw_local_irq_save(flags);
retval = *m;
*m = val;
raw_local_irq_restore(flags); /* implies memory barrier */
}
smp_llsc_mb();
return retval;
}
#else
extern __u64 __xchg_u64_unsupported_on_32bit_kernels(volatile __u64 * m, __u64 val);
#define __xchg_u64 __xchg_u64_unsupported_on_32bit_kernels
#endif
static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
{
switch (size) {
case 4:
return __xchg_u32(ptr, x);
case 8:
return __xchg_u64(ptr, x);
}
return x;
}
#define xchg(ptr, x) \
({ \
BUILD_BUG_ON(sizeof(*(ptr)) & ~0xc); \
\
((__typeof__(*(ptr))) \
__xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \
})
#define __HAVE_ARCH_CMPXCHG 1
#define __cmpxchg_asm(ld, st, m, old, new) \
({ \
__typeof(*(m)) __ret; \
\
if (kernel_uses_llsc && R10000_LLSC_WAR) { \
__asm__ __volatile__( \
" .set push \n" \
" .set noat \n" \
" .set arch=r4000 \n" \
"1: " ld " %0, %2 # __cmpxchg_asm \n" \
" bne %0, %z3, 2f \n" \
" .set mips0 \n" \
" move $1, %z4 \n" \
" .set arch=r4000 \n" \
" " st " $1, %1 \n" \
" beqzl $1, 1b \n" \
"2: \n" \
" .set pop \n" \
: "=&r" (__ret), "=" GCC_OFF_SMALL_ASM() (*m) \
: GCC_OFF_SMALL_ASM() (*m), "Jr" (old), "Jr" (new) \
: "memory"); \
} else if (kernel_uses_llsc) { \
__asm__ __volatile__( \
" .set push \n" \
" .set noat \n" \
" .set "MIPS_ISA_ARCH_LEVEL" \n" \
"1: " ld " %0, %2 # __cmpxchg_asm \n" \
" bne %0, %z3, 2f \n" \
" .set mips0 \n" \
" move $1, %z4 \n" \
" .set "MIPS_ISA_ARCH_LEVEL" \n" \
" " st " $1, %1 \n" \
" beqz $1, 1b \n" \
" .set pop \n" \
"2: \n" \
: "=&r" (__ret), "=" GCC_OFF_SMALL_ASM() (*m) \
: GCC_OFF_SMALL_ASM() (*m), "Jr" (old), "Jr" (new) \
: "memory"); \
} else { \
unsigned long __flags; \
\
raw_local_irq_save(__flags); \
__ret = *m; \
if (__ret == old) \
*m = new; \
raw_local_irq_restore(__flags); \
} \
\
__ret; \
})
/*
* This function doesn't exist, so you'll get a linker error
* if something tries to do an invalid cmpxchg().
*/
extern void __cmpxchg_called_with_bad_pointer(void);
#define __cmpxchg(ptr, old, new, pre_barrier, post_barrier) \
({ \
__typeof__(ptr) __ptr = (ptr); \
__typeof__(*(ptr)) __old = (old); \
__typeof__(*(ptr)) __new = (new); \
__typeof__(*(ptr)) __res = 0; \
\
pre_barrier; \
\
switch (sizeof(*(__ptr))) { \
case 4: \
__res = __cmpxchg_asm("ll", "sc", __ptr, __old, __new); \
break; \
case 8: \
if (sizeof(long) == 8) { \
__res = __cmpxchg_asm("lld", "scd", __ptr, \
__old, __new); \
break; \
} \
default: \
__cmpxchg_called_with_bad_pointer(); \
break; \
} \
\
post_barrier; \
\
__res; \
})
#define cmpxchg(ptr, old, new) __cmpxchg(ptr, old, new, smp_mb__before_llsc(), smp_llsc_mb())
#define cmpxchg_local(ptr, old, new) __cmpxchg(ptr, old, new, , )
#ifdef CONFIG_64BIT
#define cmpxchg64_local(ptr, o, n) \
({ \
BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
cmpxchg_local((ptr), (o), (n)); \
})
#define cmpxchg64(ptr, o, n) \
({ \
BUILD_BUG_ON(sizeof(*(ptr)) != 8); \
cmpxchg((ptr), (o), (n)); \
})
#else
#include <asm-generic/cmpxchg-local.h>
#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
#define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n))
#endif
#endif /* __ASM_CMPXCHG_H */