diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-i386/rwlock.h |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/asm-i386/rwlock.h')
-rw-r--r-- | include/asm-i386/rwlock.h | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/include/asm-i386/rwlock.h b/include/asm-i386/rwlock.h new file mode 100644 index 000000000000..b57cc7afdf7e --- /dev/null +++ b/include/asm-i386/rwlock.h | |||
@@ -0,0 +1,71 @@ | |||
1 | /* include/asm-i386/rwlock.h | ||
2 | * | ||
3 | * Helpers used by both rw spinlocks and rw semaphores. | ||
4 | * | ||
5 | * Based in part on code from semaphore.h and | ||
6 | * spinlock.h Copyright 1996 Linus Torvalds. | ||
7 | * | ||
8 | * Copyright 1999 Red Hat, Inc. | ||
9 | * | ||
10 | * Written by Benjamin LaHaise. | ||
11 | * | ||
12 | * This program is free software; you can redistribute it and/or | ||
13 | * modify it under the terms of the GNU General Public License | ||
14 | * as published by the Free Software Foundation; either version | ||
15 | * 2 of the License, or (at your option) any later version. | ||
16 | */ | ||
17 | #ifndef _ASM_I386_RWLOCK_H | ||
18 | #define _ASM_I386_RWLOCK_H | ||
19 | |||
20 | #define RW_LOCK_BIAS 0x01000000 | ||
21 | #define RW_LOCK_BIAS_STR "0x01000000" | ||
22 | |||
23 | #define __build_read_lock_ptr(rw, helper) \ | ||
24 | asm volatile(LOCK "subl $1,(%0)\n\t" \ | ||
25 | "jns 1f\n" \ | ||
26 | "call " helper "\n\t" \ | ||
27 | "1:\n" \ | ||
28 | ::"a" (rw) : "memory") | ||
29 | |||
30 | #define __build_read_lock_const(rw, helper) \ | ||
31 | asm volatile(LOCK "subl $1,%0\n\t" \ | ||
32 | "jns 1f\n" \ | ||
33 | "pushl %%eax\n\t" \ | ||
34 | "leal %0,%%eax\n\t" \ | ||
35 | "call " helper "\n\t" \ | ||
36 | "popl %%eax\n\t" \ | ||
37 | "1:\n" \ | ||
38 | :"=m" (*(volatile int *)rw) : : "memory") | ||
39 | |||
40 | #define __build_read_lock(rw, helper) do { \ | ||
41 | if (__builtin_constant_p(rw)) \ | ||
42 | __build_read_lock_const(rw, helper); \ | ||
43 | else \ | ||
44 | __build_read_lock_ptr(rw, helper); \ | ||
45 | } while (0) | ||
46 | |||
47 | #define __build_write_lock_ptr(rw, helper) \ | ||
48 | asm volatile(LOCK "subl $" RW_LOCK_BIAS_STR ",(%0)\n\t" \ | ||
49 | "jz 1f\n" \ | ||
50 | "call " helper "\n\t" \ | ||
51 | "1:\n" \ | ||
52 | ::"a" (rw) : "memory") | ||
53 | |||
54 | #define __build_write_lock_const(rw, helper) \ | ||
55 | asm volatile(LOCK "subl $" RW_LOCK_BIAS_STR ",%0\n\t" \ | ||
56 | "jz 1f\n" \ | ||
57 | "pushl %%eax\n\t" \ | ||
58 | "leal %0,%%eax\n\t" \ | ||
59 | "call " helper "\n\t" \ | ||
60 | "popl %%eax\n\t" \ | ||
61 | "1:\n" \ | ||
62 | :"=m" (*(volatile int *)rw) : : "memory") | ||
63 | |||
64 | #define __build_write_lock(rw, helper) do { \ | ||
65 | if (__builtin_constant_p(rw)) \ | ||
66 | __build_write_lock_const(rw, helper); \ | ||
67 | else \ | ||
68 | __build_write_lock_ptr(rw, helper); \ | ||
69 | } while (0) | ||
70 | |||
71 | #endif | ||