projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| ecaf45ee AK |
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 | ||
| ecaf45ee AK |
16 | #include <linux/linkage.h> |
| 17 | #include <asm/rwlock.h> | |
| 7e02cb94 AB |
18 | #include <asm/alternative-asm.h> |
| 19 | #include <asm/frame.h> | |
| ecaf45ee AK |
20 | #include <asm/dwarf2.h> |
| 21 | ||
| 22 | /* | |
| 23 | * The semaphore operations have a special calling sequence that | |
| 24 | * allow us to do a simpler in-line version of them. These routines | |
| 25 | * need to convert that sequence back into the C sequence when | |
| 26 | * there is contention on the semaphore. | |
| 27 | * | |
| 28 | * %eax contains the semaphore pointer on entry. Save the C-clobbered | |
| 29 | * registers (%eax, %edx and %ecx) except %eax whish is either a return | |
| 30 | * value or just clobbered.. | |
| 31 | */ | |
| c6c2d7a0 | 32 | .section .sched.text, "ax" |
| ecaf45ee AK |
33 | |
| 34 | /* | |
| 35 | * rw spinlock fallbacks | |
| 36 | */ | |
| 37 | #ifdef CONFIG_SMP | |
| 38 | ENTRY(__write_lock_failed) | |
| 39 | CFI_STARTPROC simple | |
| 40 | FRAME | |
| 41 | 2: LOCK_PREFIX | |
| 42 | addl $ RW_LOCK_BIAS,(%eax) | |
| 43 | 1: rep; nop | |
| 44 | cmpl $ RW_LOCK_BIAS,(%eax) | |
| 45 | jne 1b | |
| 46 | LOCK_PREFIX | |
| 47 | subl $ RW_LOCK_BIAS,(%eax) | |
| 48 | jnz 2b | |
| 49 | ENDFRAME | |
| 50 | ret | |
| 51 | CFI_ENDPROC | |
| 6b8be6df | 52 | ENDPROC(__write_lock_failed) |
| ecaf45ee AK |
53 | |
| 54 | ENTRY(__read_lock_failed) | |
| 55 | CFI_STARTPROC | |
| 56 | FRAME | |
| 57 | 2: LOCK_PREFIX | |
| 58 | incl (%eax) | |
| 59 | 1: rep; nop | |
| 60 | cmpl $1,(%eax) | |
| 61 | js 1b | |
| 62 | LOCK_PREFIX | |
| 63 | decl (%eax) | |
| 64 | js 2b | |
| 65 | ENDFRAME | |
| 66 | ret | |
| 67 | CFI_ENDPROC | |
| 6b8be6df | 68 | ENDPROC(__read_lock_failed) |
| ecaf45ee AK |
69 | |
| 70 | #endif | |
| add659bf | 71 | |
| 88271e9e IM |
72 | #ifdef CONFIG_RWSEM_XCHGADD_ALGORITHM |
| 73 | ||
| add659bf AK |
74 | /* Fix up special calling conventions */ |
| 75 | ENTRY(call_rwsem_down_read_failed) | |
| 76 | CFI_STARTPROC | |
| 77 | push %ecx | |
| 78 | CFI_ADJUST_CFA_OFFSET 4 | |
| 79 | CFI_REL_OFFSET ecx,0 | |
| 80 | push %edx | |
| 81 | CFI_ADJUST_CFA_OFFSET 4 | |
| 82 | CFI_REL_OFFSET edx,0 | |
| 83 | call rwsem_down_read_failed | |
| 84 | pop %edx | |
| 85 | CFI_ADJUST_CFA_OFFSET -4 | |
| 86 | pop %ecx | |
| 87 | CFI_ADJUST_CFA_OFFSET -4 | |
| 88 | ret | |
| 89 | CFI_ENDPROC | |
| 6b8be6df | 90 | ENDPROC(call_rwsem_down_read_failed) |
| add659bf AK |
91 | |
| 92 | ENTRY(call_rwsem_down_write_failed) | |
| 93 | CFI_STARTPROC | |
| 94 | push %ecx | |
| 95 | CFI_ADJUST_CFA_OFFSET 4 | |
| 96 | CFI_REL_OFFSET ecx,0 | |
| 97 | calll rwsem_down_write_failed | |
| 98 | pop %ecx | |
| 99 | CFI_ADJUST_CFA_OFFSET -4 | |
| 100 | ret | |
| 101 | CFI_ENDPROC | |
| 6b8be6df | 102 | ENDPROC(call_rwsem_down_write_failed) |
| add659bf AK |
103 | |
| 104 | ENTRY(call_rwsem_wake) | |
| 105 | CFI_STARTPROC | |
| 106 | decw %dx /* do nothing if still outstanding active readers */ | |
| 107 | jnz 1f | |
| 108 | push %ecx | |
| 109 | CFI_ADJUST_CFA_OFFSET 4 | |
| 110 | CFI_REL_OFFSET ecx,0 | |
| 111 | call rwsem_wake | |
| 112 | pop %ecx | |
| 113 | CFI_ADJUST_CFA_OFFSET -4 | |
| 114 | 1: ret | |
| 115 | CFI_ENDPROC | |
| 6b8be6df | 116 | ENDPROC(call_rwsem_wake) |
| add659bf AK |
117 | |
| 118 | /* Fix up special calling conventions */ | |
| 119 | ENTRY(call_rwsem_downgrade_wake) | |
| 120 | CFI_STARTPROC | |
| 121 | push %ecx | |
| 122 | CFI_ADJUST_CFA_OFFSET 4 | |
| 123 | CFI_REL_OFFSET ecx,0 | |
| 124 | push %edx | |
| 125 | CFI_ADJUST_CFA_OFFSET 4 | |
| 126 | CFI_REL_OFFSET edx,0 | |
| 127 | call rwsem_downgrade_wake | |
| 128 | pop %edx | |
| 129 | CFI_ADJUST_CFA_OFFSET -4 | |
| 130 | pop %ecx | |
| 131 | CFI_ADJUST_CFA_OFFSET -4 | |
| 132 | ret | |
| 133 | CFI_ENDPROC | |
| 6b8be6df | 134 | ENDPROC(call_rwsem_downgrade_wake) |
| add659bf | 135 | |
| 88271e9e | 136 | #endif |