Andi Kleen | ecaf45e | 2006-09-26 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 |
| 34 | ENTRY(__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 | |
| 55 | ENTRY(__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 | |
| 76 | ENTRY(__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 | |
| 97 | ENTRY(__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 |
| 122 | ENTRY(__write_lock_failed) |
| 123 | CFI_STARTPROC simple |
| 124 | FRAME |
| 125 | 2: LOCK_PREFIX |
| 126 | addl $ RW_LOCK_BIAS,(%eax) |
| 127 | 1: 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 | |
| 138 | ENTRY(__read_lock_failed) |
| 139 | CFI_STARTPROC |
| 140 | FRAME |
| 141 | 2: LOCK_PREFIX |
| 142 | incl (%eax) |
| 143 | 1: 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 |