aboutsummaryrefslogtreecommitdiffstats
path: root/arch/x86/lib/atomic64_cx8_32.S
blob: f5cc9eb1d51bc02ef817bd664c7810f4f5b928b1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
/*
 * atomic64_t for 586+
 *
 * Copyright © 2010  Luca Barbieri
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */

#include <linux/linkage.h>
#include <asm/alternative-asm.h>
#include <asm/dwarf2.h>

.macro SAVE reg
	pushl_cfi %\reg
	CFI_REL_OFFSET \reg, 0
.endm

.macro RESTORE reg
	popl_cfi %\reg
	CFI_RESTORE \reg
.endm

.macro read64 reg
	movl %ebx, %eax
	movl %ecx, %edx
/* we need LOCK_PREFIX since otherwise cmpxchg8b always does the write */
	LOCK_PREFIX
	cmpxchg8b (\reg)
.endm

ENTRY(atomic64_read_cx8)
	CFI_STARTPROC

	read64 %ecx
	ret
	CFI_ENDPROC
ENDPROC(atomic64_read_cx8)

ENTRY(atomic64_set_cx8)
	CFI_STARTPROC

1:
/* we don't need LOCK_PREFIX since aligned 64-bit writes
 * are atomic on 586 and newer */
	cmpxchg8b (%esi)
	jne 1b

	ret
	CFI_ENDPROC
ENDPROC(atomic64_set_cx8)

ENTRY(atomic64_xchg_cx8)
	CFI_STARTPROC

1:
	LOCK_PREFIX
	cmpxchg8b (%esi)
	jne 1b

	ret
	CFI_ENDPROC
ENDPROC(atomic64_xchg_cx8)

.macro addsub_return func ins insc
ENTRY(atomic64_\func\()_return_cx8)
	CFI_STARTPROC
	SAVE ebp
	SAVE ebx
	SAVE esi
	SAVE edi

	movl %eax, %esi
	movl %edx, %edi
	movl %ecx, %ebp

	read64 %ecx
1:
	movl %eax, %ebx
	movl %edx, %ecx
	\ins\()l %esi, %ebx
	\insc\()l %edi, %ecx
	LOCK_PREFIX
	cmpxchg8b (%ebp)
	jne 1b

10:
	movl %ebx, %eax
	movl %ecx, %edx
	RESTORE edi
	RESTORE esi
	RESTORE ebx
	RESTORE ebp
	ret
	CFI_ENDPROC
ENDPROC(atomic64_\func\()_return_cx8)
.endm

addsub_return add add adc
addsub_return sub sub sbb

.macro incdec_return func ins insc
ENTRY(atomic64_\func\()_return_cx8)
	CFI_STARTPROC
	SAVE ebx

	read64 %esi
1:
	movl %eax, %ebx
	movl %edx, %ecx
	\ins\()l $1, %ebx
	\insc\()l $0, %ecx
	LOCK_PREFIX
	cmpxchg8b (%esi)
	jne 1b

10:
	movl %ebx, %eax
	movl %ecx, %edx
	RESTORE ebx
	ret
	CFI_ENDPROC
ENDPROC(atomic64_\func\()_return_cx8)
.endm

incdec_return inc add adc
incdec_return dec sub sbb

ENTRY(atomic64_dec_if_positive_cx8)
	CFI_STARTPROC
	SAVE ebx

	read64 %esi
1:
	movl %eax, %ebx
	movl %edx, %ecx
	subl $1, %ebx
	sbb $0, %ecx
	js 2f
	LOCK_PREFIX
	cmpxchg8b (%esi)
	jne 1b

2:
	movl %ebx, %eax
	movl %ecx, %edx
	RESTORE ebx
	ret
	CFI_ENDPROC
ENDPROC(atomic64_dec_if_positive_cx8)

ENTRY(atomic64_add_unless_cx8)
	CFI_STARTPROC
	SAVE ebp
	SAVE ebx
/* these just push these two parameters on the stack */
	SAVE edi
	SAVE ecx

	movl %eax, %ebp
	movl %edx, %edi

	read64 %esi
1:
	cmpl %eax, 0(%esp)
	je 4f
2:
	movl %eax, %ebx
	movl %edx, %ecx
	addl %ebp, %ebx
	adcl %edi, %ecx
	LOCK_PREFIX
	cmpxchg8b (%esi)
	jne 1b

	movl $1, %eax
3:
	addl $8, %esp
	CFI_ADJUST_CFA_OFFSET -8
	RESTORE ebx
	RESTORE ebp
	ret
4:
	cmpl %edx, 4(%esp)
	jne 2b
	xorl %eax, %eax
	jmp 3b
	CFI_ENDPROC
ENDPROC(atomic64_add_unless_cx8)

ENTRY(atomic64_inc_not_zero_cx8)
	CFI_STARTPROC
	SAVE ebx

	read64 %esi
1:
	movl %eax, %ecx
	orl %edx, %ecx
	jz 3f
	movl %eax, %ebx
	xorl %ecx, %ecx
	addl $1, %ebx
	adcl %edx, %ecx
	LOCK_PREFIX
	cmpxchg8b (%esi)
	jne 1b

	movl $1, %eax
3:
	RESTORE ebx
	ret
	CFI_ENDPROC
ENDPROC(atomic64_inc_not_zero_cx8)

Privacy Policy