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gerrit-public.fairphone.software / fp2-dev / kernel / msm / 78b656b8bf933101b42409b4492734b23427bfc3 / . / arch / i386 / lib / semaphore.S
blob: 01f80b5c45d2fde74444b1be34b39016e7310e8f [file] [log] [blame]
Andi Kleenecaf45e2006-09-26 10:52:29 +0200[diff] [blame]1/*
2 * i386 semaphore implementation.
3 *
4 * (C) Copyright 1999 Linus Torvalds
5 *
6 * Portions Copyright 1999 Red Hat, Inc.
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
12 *
13 * rw semaphores implemented November 1999 by Benjamin LaHaise <bcrl@kvack.org>
14 */
15
16#include <linux/config.h>
17#include <linux/linkage.h>
18#include <asm/rwlock.h>
19#include <asm/alternative-asm.i>
20#include <asm/frame.i>
21#include <asm/dwarf2.h>
22
23/*
24 * The semaphore operations have a special calling sequence that
25 * allow us to do a simpler in-line version of them. These routines
26 * need to convert that sequence back into the C sequence when
27 * there is contention on the semaphore.
28 *
29 * %eax contains the semaphore pointer on entry. Save the C-clobbered
30 * registers (%eax, %edx and %ecx) except %eax whish is either a return
31 * value or just clobbered..
32 */
33 .section .sched.text
34ENTRY(__down_failed)
35 CFI_STARTPROC
36 FRAME
37 pushl %edx
38 CFI_ADJUST_CFA_OFFSET 4
39 CFI_REL_OFFSET edx,0
40 pushl %ecx
41 CFI_ADJUST_CFA_OFFSET 4
42 CFI_REL_OFFSET ecx,0
43 call __down
44 popl %ecx
45 CFI_ADJUST_CFA_OFFSET -4
46 CFI_RESTORE ecx
47 popl %edx
48 CFI_ADJUST_CFA_OFFSET -4
49 CFI_RESTORE edx
50 ENDFRAME
51 ret
52 CFI_ENDPROC
53 END(__down_failed)
54
55ENTRY(__down_failed_interruptible)
56 CFI_STARTPROC
57 FRAME
58 pushl %edx
59 CFI_ADJUST_CFA_OFFSET 4
60 CFI_REL_OFFSET edx,0
61 pushl %ecx
62 CFI_ADJUST_CFA_OFFSET 4
63 CFI_REL_OFFSET ecx,0
64 call __down_interruptible
65 popl %ecx
66 CFI_ADJUST_CFA_OFFSET -4
67 CFI_RESTORE ecx
68 popl %edx
69 CFI_ADJUST_CFA_OFFSET -4
70 CFI_RESTORE edx
71 ENDFRAME
72 ret
73 CFI_ENDPROC
74 END(__down_failed_interruptible)
75
76ENTRY(__down_failed_trylock)
77 CFI_STARTPROC
78 FRAME
79 pushl %edx
80 CFI_ADJUST_CFA_OFFSET 4
81 CFI_REL_OFFSET edx,0
82 pushl %ecx
83 CFI_ADJUST_CFA_OFFSET 4
84 CFI_REL_OFFSET ecx,0
85 call __down_trylock
86 popl %ecx
87 CFI_ADJUST_CFA_OFFSET -4
88 CFI_RESTORE ecx
89 popl %edx
90 CFI_ADJUST_CFA_OFFSET -4
91 CFI_RESTORE edx
92 ENDFRAME
93 ret
94 CFI_ENDPROC
95 END(__down_failed_trylock)
96
97ENTRY(__up_wakeup)
98 CFI_STARTPROC
99 FRAME
100 pushl %edx
101 CFI_ADJUST_CFA_OFFSET 4
102 CFI_REL_OFFSET edx,0
103 pushl %ecx
104 CFI_ADJUST_CFA_OFFSET 4
105 CFI_REL_OFFSET ecx,0
106 call __up
107 popl %ecx
108 CFI_ADJUST_CFA_OFFSET -4
109 CFI_RESTORE ecx
110 popl %edx
111 CFI_ADJUST_CFA_OFFSET -4
112 CFI_RESTORE edx
113 ENDFRAME
114 ret
115 CFI_ENDPROC
116 END(__up_wakeup)
117
118/*
119 * rw spinlock fallbacks
120 */
121#ifdef CONFIG_SMP
122ENTRY(__write_lock_failed)
123 CFI_STARTPROC simple
124 FRAME
1252: LOCK_PREFIX
126 addl $ RW_LOCK_BIAS,(%eax)
1271: rep; nop
128 cmpl $ RW_LOCK_BIAS,(%eax)
129 jne 1b
130 LOCK_PREFIX
131 subl $ RW_LOCK_BIAS,(%eax)
132 jnz 2b
133 ENDFRAME
134 ret
135 CFI_ENDPROC
136 END(__write_lock_failed)
137
138ENTRY(__read_lock_failed)
139 CFI_STARTPROC
140 FRAME
1412: LOCK_PREFIX
142 incl (%eax)
1431: rep; nop
144 cmpl $1,(%eax)
145 js 1b
146 LOCK_PREFIX
147 decl (%eax)
148 js 2b
149 ENDFRAME
150 ret
151 CFI_ENDPROC
152 END(__read_lock_failed)
153
154#endif
Andi Kleenadd659b2006-09-26 10:52:31 +0200[diff] [blame]155
156/* Fix up special calling conventions */
157ENTRY(call_rwsem_down_read_failed)
158 CFI_STARTPROC
159 push %ecx
160 CFI_ADJUST_CFA_OFFSET 4
161 CFI_REL_OFFSET ecx,0
162 push %edx
163 CFI_ADJUST_CFA_OFFSET 4
164 CFI_REL_OFFSET edx,0
165 call rwsem_down_read_failed
166 pop %edx
167 CFI_ADJUST_CFA_OFFSET -4
168 pop %ecx
169 CFI_ADJUST_CFA_OFFSET -4
170 ret
171 CFI_ENDPROC
172 END(call_rwsem_down_read_failed)
173
174ENTRY(call_rwsem_down_write_failed)
175 CFI_STARTPROC
176 push %ecx
177 CFI_ADJUST_CFA_OFFSET 4
178 CFI_REL_OFFSET ecx,0
179 calll rwsem_down_write_failed
180 pop %ecx
181 CFI_ADJUST_CFA_OFFSET -4
182 ret
183 CFI_ENDPROC
184 END(call_rwsem_down_write_failed)
185
186ENTRY(call_rwsem_wake)
187 CFI_STARTPROC
188 decw %dx /* do nothing if still outstanding active readers */
189 jnz 1f
190 push %ecx
191 CFI_ADJUST_CFA_OFFSET 4
192 CFI_REL_OFFSET ecx,0
193 call rwsem_wake
194 pop %ecx
195 CFI_ADJUST_CFA_OFFSET -4
1961: ret
197 CFI_ENDPROC
198 END(call_rwsem_wake)
199
200/* Fix up special calling conventions */
201ENTRY(call_rwsem_downgrade_wake)
202 CFI_STARTPROC
203 push %ecx
204 CFI_ADJUST_CFA_OFFSET 4
205 CFI_REL_OFFSET ecx,0
206 push %edx
207 CFI_ADJUST_CFA_OFFSET 4
208 CFI_REL_OFFSET edx,0
209 call rwsem_downgrade_wake
210 pop %edx
211 CFI_ADJUST_CFA_OFFSET -4
212 pop %ecx
213 CFI_ADJUST_CFA_OFFSET -4
214 ret
215 CFI_ENDPROC
216 END(call_rwsem_downgrade_wake)
217