1/*
 2 *	This program is free software; you can redistribute it and/or
 3 *	modify it under the terms of the GNU General Public License
 4 *	as published by the Free Software Foundation; version 2
 5 *	of the License.
 6 *
 
 
 
 
 
 
 7 */
 
 8
 9#include <linux/linkage.h>
10#include <asm/alternative-asm.h>
11#include <asm/frame.h>
12#include <asm/dwarf2.h>
13
 
 
 
 
14
15.text
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
16
17/*
 
 
18 * Inputs:
19 * %esi : memory location to compare
20 * %eax : low 32 bits of old value
21 * %edx : high 32 bits of old value
22 * %ebx : low 32 bits of new value
23 * %ecx : high 32 bits of new value
 
 
24 */
25ENTRY(cmpxchg8b_emu)
26CFI_STARTPROC
27
28#
29# Emulate 'cmpxchg8b (%esi)' on UP except we don't
30# set the whole ZF thing (caller will just compare
31# eax:edx with the expected value)
32#
33cmpxchg8b_emu:
34	pushfl
35	cli
36
37	cmpl  (%esi), %eax
38	jne not_same
39	cmpl 4(%esi), %edx
40	jne half_same
41
42	movl %ebx,  (%esi)
43	movl %ecx, 4(%esi)
 
 
44
45	popfl
46	ret
 
 
 
 
47
48 not_same:
49	movl  (%esi), %eax
50 half_same:
51	movl 4(%esi), %edx
52
53	popfl
54	ret
 
 
55
56CFI_ENDPROC
57ENDPROC(cmpxchg8b_emu)

 1/* SPDX-License-Identifier: GPL-2.0-only */
 2
 3#include <linux/export.h>
 4#include <linux/linkage.h>
 5#include <asm/percpu.h>
 6#include <asm/processor-flags.h>
 7
 8.text
 9
10#ifndef CONFIG_X86_CMPXCHG64
11
12/*
13 * Emulate 'cmpxchg8b (%esi)' on UP
 
 
 
14 *
15 * Inputs:
16 * %esi : memory location to compare
17 * %eax : low 32 bits of old value
18 * %edx : high 32 bits of old value
19 * %ebx : low 32 bits of new value
20 * %ecx : high 32 bits of new value
21 */
22SYM_FUNC_START(cmpxchg8b_emu)
23
24	pushfl
25	cli
 
 
26
27	cmpl	(%esi), %eax
28	jne	.Lnot_same
29	cmpl	4(%esi), %edx
30	jne	.Lnot_same
31
32	movl	%ebx, (%esi)
33	movl	%ecx, 4(%esi)
34
35	orl	$X86_EFLAGS_ZF, (%esp)
36
37	popfl
38	RET
39
40.Lnot_same:
41	movl	(%esi), %eax
42	movl	4(%esi), %edx
43
44	andl	$(~X86_EFLAGS_ZF), (%esp)
45
46	popfl
47	RET
48
49SYM_FUNC_END(cmpxchg8b_emu)
50EXPORT_SYMBOL(cmpxchg8b_emu)
51
52#endif
53
54#ifndef CONFIG_UML
55
56/*
57 * Emulate 'cmpxchg8b %fs:(%rsi)'
58 *
59 * Inputs:
60 * %esi : memory location to compare
61 * %eax : low 32 bits of old value
62 * %edx : high 32 bits of old value
63 * %ebx : low 32 bits of new value
64 * %ecx : high 32 bits of new value
65 *
66 * Notably this is not LOCK prefixed and is not safe against NMIs
67 */
68SYM_FUNC_START(this_cpu_cmpxchg8b_emu)
 
69
 
 
 
 
 
 
70	pushfl
71	cli
72
73	cmpl	__percpu (%esi), %eax
74	jne	.Lnot_same2
75	cmpl	__percpu 4(%esi), %edx
76	jne	.Lnot_same2
77
78	movl	%ebx, __percpu (%esi)
79	movl	%ecx, __percpu 4(%esi)
80
81	orl	$X86_EFLAGS_ZF, (%esp)
82
83	popfl
84	RET
85
86.Lnot_same2:
87	movl	__percpu (%esi), %eax
88	movl	__percpu 4(%esi), %edx
89
90	andl	$(~X86_EFLAGS_ZF), (%esp)
 
 
 
91
92	popfl
93	RET
94
95SYM_FUNC_END(this_cpu_cmpxchg8b_emu)
96
97#endif