1/* SPDX-License-Identifier: GPL-2.0-only */
2
3#include <linux/linkage.h>
4#include <asm/export.h>
5
6.text
7
8/*
9 * Inputs:
10 * %esi : memory location to compare
11 * %eax : low 32 bits of old value
12 * %edx : high 32 bits of old value
13 * %ebx : low 32 bits of new value
14 * %ecx : high 32 bits of new value
15 */
16SYM_FUNC_START(cmpxchg8b_emu)
17
18#
19# Emulate 'cmpxchg8b (%esi)' on UP except we don't
20# set the whole ZF thing (caller will just compare
21# eax:edx with the expected value)
22#
23	pushfl
24	cli
25
26	cmpl  (%esi), %eax
27	jne .Lnot_same
28	cmpl 4(%esi), %edx
29	jne .Lhalf_same
30
31	movl %ebx,  (%esi)
32	movl %ecx, 4(%esi)
33
34	popfl
35	RET
36
37.Lnot_same:
38	movl  (%esi), %eax
39.Lhalf_same:
40	movl 4(%esi), %edx
41
42	popfl
43	RET
44
45SYM_FUNC_END(cmpxchg8b_emu)
46EXPORT_SYMBOL(cmpxchg8b_emu)
47