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/*
* 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/irqflags.h>
#define __HAVE_ARCH_CMPXCHG 1
#define __cmpxchg_asm(ld, st, m, old, new) \
({ \
__typeof(*(m)) __ret; \
\
if (cpu_has_llsc && R10000_LLSC_WAR) { \
__asm__ __volatile__( \
" .set push \n" \
" .set noat \n" \
" .set mips3 \n" \
"1: " ld " %0, %2 # __cmpxchg_asm \n" \
" bne %0, %z3, 2f \n" \
" .set mips0 \n" \
" move $1, %z4 \n" \
" .set mips3 \n" \
" " st " $1, %1 \n" \
" beqzl $1, 1b \n" \
"2: \n" \
" .set pop \n" \
: "=&r" (__ret), "=R" (*m) \
: "R" (*m), "Jr" (old), "Jr" (new) \
: "memory"); \
} else if (cpu_has_llsc) { \
__asm__ __volatile__( \
" .set push \n" \
" .set noat \n" \
" .set mips3 \n" \
"1: " ld " %0, %2 # __cmpxchg_asm \n" \
" bne %0, %z3, 2f \n" \
" .set mips0 \n" \
" move $1, %z4 \n" \
" .set mips3 \n" \
" " st " $1, %1 \n" \
" beqz $1, 3f \n" \
"2: \n" \
" .subsection 2 \n" \
"3: b 1b \n" \
" .previous \n" \
" .set pop \n" \
: "=&r" (__ret), "=R" (*m) \
: "R" (*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,barrier) \
({ \
__typeof__(ptr) __ptr = (ptr); \
__typeof__(*(ptr)) __old = (old); \
__typeof__(*(ptr)) __new = (new); \
__typeof__(*(ptr)) __res = 0; \
\
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; \
} \
\
barrier; \
\
__res; \
})
#define cmpxchg(ptr, old, new) __cmpxchg(ptr, old, new, smp_llsc_mb())
#define cmpxchg_local(ptr, old, new) __cmpxchg(ptr, old, new,)
#endif /* __ASM_CMPXCHG_H */
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