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/* SPDX-License-Identifier: GPL-2.0-only */
#include <linux/export.h>
#include <linux/linkage.h>
#include <asm/percpu.h>
#include <asm/processor-flags.h>
.text
#ifndef CONFIG_X86_CMPXCHG64
/*
* Emulate 'cmpxchg8b (%esi)' on UP
*
* Inputs:
* %esi : memory location to compare
* %eax : low 32 bits of old value
* %edx : high 32 bits of old value
* %ebx : low 32 bits of new value
* %ecx : high 32 bits of new value
*/
SYM_FUNC_START(cmpxchg8b_emu)
pushfl
cli
cmpl (%esi), %eax
jne .Lnot_same
cmpl 4(%esi), %edx
jne .Lnot_same
movl %ebx, (%esi)
movl %ecx, 4(%esi)
orl $X86_EFLAGS_ZF, (%esp)
popfl
RET
.Lnot_same:
movl (%esi), %eax
movl 4(%esi), %edx
andl $(~X86_EFLAGS_ZF), (%esp)
popfl
RET
SYM_FUNC_END(cmpxchg8b_emu)
EXPORT_SYMBOL(cmpxchg8b_emu)
#endif
#ifndef CONFIG_UML
/*
* Emulate 'cmpxchg8b %fs:(%rsi)'
*
* Inputs:
* %esi : memory location to compare
* %eax : low 32 bits of old value
* %edx : high 32 bits of old value
* %ebx : low 32 bits of new value
* %ecx : high 32 bits of new value
*
* Notably this is not LOCK prefixed and is not safe against NMIs
*/
SYM_FUNC_START(this_cpu_cmpxchg8b_emu)
pushfl
cli
cmpl __percpu (%esi), %eax
jne .Lnot_same2
cmpl __percpu 4(%esi), %edx
jne .Lnot_same2
movl %ebx, __percpu (%esi)
movl %ecx, __percpu 4(%esi)
orl $X86_EFLAGS_ZF, (%esp)
popfl
RET
.Lnot_same2:
movl __percpu (%esi), %eax
movl __percpu 4(%esi), %edx
andl $(~X86_EFLAGS_ZF), (%esp)
popfl
RET
SYM_FUNC_END(this_cpu_cmpxchg8b_emu)
#endif
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