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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_CMPXCHG_32_H
#define _ASM_X86_CMPXCHG_32_H
/*
* Note: if you use set64_bit(), __cmpxchg64(), or their variants,
* you need to test for the feature in boot_cpu_data.
*/
#ifdef CONFIG_X86_CMPXCHG64
#define arch_cmpxchg64(ptr, o, n) \
((__typeof__(*(ptr)))__cmpxchg64((ptr), (unsigned long long)(o), \
(unsigned long long)(n)))
#define arch_cmpxchg64_local(ptr, o, n) \
((__typeof__(*(ptr)))__cmpxchg64_local((ptr), (unsigned long long)(o), \
(unsigned long long)(n)))
#define arch_try_cmpxchg64(ptr, po, n) \
__try_cmpxchg64((ptr), (unsigned long long *)(po), \
(unsigned long long)(n))
#endif
static inline u64 __cmpxchg64(volatile u64 *ptr, u64 old, u64 new)
{
u64 prev;
asm volatile(LOCK_PREFIX "cmpxchg8b %1"
: "=A" (prev),
"+m" (*ptr)
: "b" ((u32)new),
"c" ((u32)(new >> 32)),
"0" (old)
: "memory");
return prev;
}
static inline u64 __cmpxchg64_local(volatile u64 *ptr, u64 old, u64 new)
{
u64 prev;
asm volatile("cmpxchg8b %1"
: "=A" (prev),
"+m" (*ptr)
: "b" ((u32)new),
"c" ((u32)(new >> 32)),
"0" (old)
: "memory");
return prev;
}
static inline bool __try_cmpxchg64(volatile u64 *ptr, u64 *pold, u64 new)
{
bool success;
u64 old = *pold;
asm volatile(LOCK_PREFIX "cmpxchg8b %[ptr]"
CC_SET(z)
: CC_OUT(z) (success),
[ptr] "+m" (*ptr),
"+A" (old)
: "b" ((u32)new),
"c" ((u32)(new >> 32))
: "memory");
if (unlikely(!success))
*pold = old;
return success;
}
#ifndef CONFIG_X86_CMPXCHG64
/*
* Building a kernel capable running on 80386 and 80486. It may be necessary
* to simulate the cmpxchg8b on the 80386 and 80486 CPU.
*/
#define arch_cmpxchg64(ptr, o, n) \
({ \
__typeof__(*(ptr)) __ret; \
__typeof__(*(ptr)) __old = (o); \
__typeof__(*(ptr)) __new = (n); \
alternative_io(LOCK_PREFIX_HERE \
"call cmpxchg8b_emu", \
"lock; cmpxchg8b (%%esi)" , \
X86_FEATURE_CX8, \
"=A" (__ret), \
"S" ((ptr)), "0" (__old), \
"b" ((unsigned int)__new), \
"c" ((unsigned int)(__new>>32)) \
: "memory"); \
__ret; })
#define arch_cmpxchg64_local(ptr, o, n) \
({ \
__typeof__(*(ptr)) __ret; \
__typeof__(*(ptr)) __old = (o); \
__typeof__(*(ptr)) __new = (n); \
alternative_io("call cmpxchg8b_emu", \
"cmpxchg8b (%%esi)" , \
X86_FEATURE_CX8, \
"=A" (__ret), \
"S" ((ptr)), "0" (__old), \
"b" ((unsigned int)__new), \
"c" ((unsigned int)(__new>>32)) \
: "memory"); \
__ret; })
#endif
#define system_has_cmpxchg_double() boot_cpu_has(X86_FEATURE_CX8)
#define system_has_cmpxchg64() boot_cpu_has(X86_FEATURE_CX8)
#endif /* _ASM_X86_CMPXCHG_32_H */
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