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 */
22 SYM_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
49 SYM_FUNC_END(cmpxchg8b_emu)
50 EXPORT_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 no
67 */
68 SYM_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
95 SYM_FUNC_END(this_cpu_cmpxchg8b_emu)
96
97 #endif
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