Commit | Line | Data |
---|---|---|
1da177e4 LT |
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 | #include <linux/config.h> | |
1da177e4 LT |
16 | #include <asm/semaphore.h> |
17 | ||
1da177e4 LT |
18 | /* |
19 | * The semaphore operations have a special calling sequence that | |
20 | * allow us to do a simpler in-line version of them. These routines | |
21 | * need to convert that sequence back into the C sequence when | |
22 | * there is contention on the semaphore. | |
23 | * | |
24 | * %eax contains the semaphore pointer on entry. Save the C-clobbered | |
25 | * registers (%eax, %edx and %ecx) except %eax whish is either a return | |
26 | * value or just clobbered.. | |
27 | */ | |
28 | asm( | |
29 | ".section .sched.text\n" | |
30 | ".align 4\n" | |
31 | ".globl __down_failed\n" | |
32 | "__down_failed:\n\t" | |
33 | #if defined(CONFIG_FRAME_POINTER) | |
34 | "pushl %ebp\n\t" | |
35 | "movl %esp,%ebp\n\t" | |
36 | #endif | |
37 | "pushl %edx\n\t" | |
38 | "pushl %ecx\n\t" | |
39 | "call __down\n\t" | |
40 | "popl %ecx\n\t" | |
41 | "popl %edx\n\t" | |
42 | #if defined(CONFIG_FRAME_POINTER) | |
43 | "movl %ebp,%esp\n\t" | |
44 | "popl %ebp\n\t" | |
45 | #endif | |
46 | "ret" | |
47 | ); | |
48 | ||
49 | asm( | |
50 | ".section .sched.text\n" | |
51 | ".align 4\n" | |
52 | ".globl __down_failed_interruptible\n" | |
53 | "__down_failed_interruptible:\n\t" | |
54 | #if defined(CONFIG_FRAME_POINTER) | |
55 | "pushl %ebp\n\t" | |
56 | "movl %esp,%ebp\n\t" | |
57 | #endif | |
58 | "pushl %edx\n\t" | |
59 | "pushl %ecx\n\t" | |
60 | "call __down_interruptible\n\t" | |
61 | "popl %ecx\n\t" | |
62 | "popl %edx\n\t" | |
63 | #if defined(CONFIG_FRAME_POINTER) | |
64 | "movl %ebp,%esp\n\t" | |
65 | "popl %ebp\n\t" | |
66 | #endif | |
67 | "ret" | |
68 | ); | |
69 | ||
70 | asm( | |
71 | ".section .sched.text\n" | |
72 | ".align 4\n" | |
73 | ".globl __down_failed_trylock\n" | |
74 | "__down_failed_trylock:\n\t" | |
75 | #if defined(CONFIG_FRAME_POINTER) | |
76 | "pushl %ebp\n\t" | |
77 | "movl %esp,%ebp\n\t" | |
78 | #endif | |
79 | "pushl %edx\n\t" | |
80 | "pushl %ecx\n\t" | |
81 | "call __down_trylock\n\t" | |
82 | "popl %ecx\n\t" | |
83 | "popl %edx\n\t" | |
84 | #if defined(CONFIG_FRAME_POINTER) | |
85 | "movl %ebp,%esp\n\t" | |
86 | "popl %ebp\n\t" | |
87 | #endif | |
88 | "ret" | |
89 | ); | |
90 | ||
91 | asm( | |
92 | ".section .sched.text\n" | |
93 | ".align 4\n" | |
94 | ".globl __up_wakeup\n" | |
95 | "__up_wakeup:\n\t" | |
96 | "pushl %edx\n\t" | |
97 | "pushl %ecx\n\t" | |
98 | "call __up\n\t" | |
99 | "popl %ecx\n\t" | |
100 | "popl %edx\n\t" | |
101 | "ret" | |
102 | ); | |
103 | ||
104 | /* | |
105 | * rw spinlock fallbacks | |
106 | */ | |
107 | #if defined(CONFIG_SMP) | |
108 | asm( | |
109 | ".section .sched.text\n" | |
110 | ".align 4\n" | |
111 | ".globl __write_lock_failed\n" | |
112 | "__write_lock_failed:\n\t" | |
113 | LOCK "addl $" RW_LOCK_BIAS_STR ",(%eax)\n" | |
114 | "1: rep; nop\n\t" | |
115 | "cmpl $" RW_LOCK_BIAS_STR ",(%eax)\n\t" | |
116 | "jne 1b\n\t" | |
117 | LOCK "subl $" RW_LOCK_BIAS_STR ",(%eax)\n\t" | |
118 | "jnz __write_lock_failed\n\t" | |
119 | "ret" | |
120 | ); | |
121 | ||
122 | asm( | |
123 | ".section .sched.text\n" | |
124 | ".align 4\n" | |
125 | ".globl __read_lock_failed\n" | |
126 | "__read_lock_failed:\n\t" | |
127 | LOCK "incl (%eax)\n" | |
128 | "1: rep; nop\n\t" | |
129 | "cmpl $1,(%eax)\n\t" | |
130 | "js 1b\n\t" | |
131 | LOCK "decl (%eax)\n\t" | |
132 | "js __read_lock_failed\n\t" | |
133 | "ret" | |
134 | ); | |
135 | #endif |