diff options
author | Thomas Gleixner <tglx@linutronix.de> | 2007-10-11 05:20:03 -0400 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2007-10-11 05:20:03 -0400 |
commit | 96a388de5dc53a8b234b3fd41f3ae2cedc9ffd42 (patch) | |
tree | d947a467aa2da3140279617bc4b9b101640d7bf4 /include/asm-x86/spinlock_32.h | |
parent | 27bd0c955648646abf2a353a8371d28c37bcd982 (diff) |
i386/x86_64: move headers to include/asm-x86
Move the headers to include/asm-x86 and fixup the
header install make rules
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/asm-x86/spinlock_32.h')
-rw-r--r-- | include/asm-x86/spinlock_32.h | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/include/asm-x86/spinlock_32.h b/include/asm-x86/spinlock_32.h new file mode 100644 index 000000000000..d3bcebed60ca --- /dev/null +++ b/include/asm-x86/spinlock_32.h | |||
@@ -0,0 +1,221 @@ | |||
1 | #ifndef __ASM_SPINLOCK_H | ||
2 | #define __ASM_SPINLOCK_H | ||
3 | |||
4 | #include <asm/atomic.h> | ||
5 | #include <asm/rwlock.h> | ||
6 | #include <asm/page.h> | ||
7 | #include <asm/processor.h> | ||
8 | #include <linux/compiler.h> | ||
9 | |||
10 | #ifdef CONFIG_PARAVIRT | ||
11 | #include <asm/paravirt.h> | ||
12 | #else | ||
13 | #define CLI_STRING "cli" | ||
14 | #define STI_STRING "sti" | ||
15 | #define CLI_STI_CLOBBERS | ||
16 | #define CLI_STI_INPUT_ARGS | ||
17 | #endif /* CONFIG_PARAVIRT */ | ||
18 | |||
19 | /* | ||
20 | * Your basic SMP spinlocks, allowing only a single CPU anywhere | ||
21 | * | ||
22 | * Simple spin lock operations. There are two variants, one clears IRQ's | ||
23 | * on the local processor, one does not. | ||
24 | * | ||
25 | * We make no fairness assumptions. They have a cost. | ||
26 | * | ||
27 | * (the type definitions are in asm/spinlock_types.h) | ||
28 | */ | ||
29 | |||
30 | static inline int __raw_spin_is_locked(raw_spinlock_t *x) | ||
31 | { | ||
32 | return *(volatile signed char *)(&(x)->slock) <= 0; | ||
33 | } | ||
34 | |||
35 | static inline void __raw_spin_lock(raw_spinlock_t *lock) | ||
36 | { | ||
37 | asm volatile("\n1:\t" | ||
38 | LOCK_PREFIX " ; decb %0\n\t" | ||
39 | "jns 3f\n" | ||
40 | "2:\t" | ||
41 | "rep;nop\n\t" | ||
42 | "cmpb $0,%0\n\t" | ||
43 | "jle 2b\n\t" | ||
44 | "jmp 1b\n" | ||
45 | "3:\n\t" | ||
46 | : "+m" (lock->slock) : : "memory"); | ||
47 | } | ||
48 | |||
49 | /* | ||
50 | * It is easier for the lock validator if interrupts are not re-enabled | ||
51 | * in the middle of a lock-acquire. This is a performance feature anyway | ||
52 | * so we turn it off: | ||
53 | * | ||
54 | * NOTE: there's an irqs-on section here, which normally would have to be | ||
55 | * irq-traced, but on CONFIG_TRACE_IRQFLAGS we never use this variant. | ||
56 | */ | ||
57 | #ifndef CONFIG_PROVE_LOCKING | ||
58 | static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags) | ||
59 | { | ||
60 | asm volatile( | ||
61 | "\n1:\t" | ||
62 | LOCK_PREFIX " ; decb %[slock]\n\t" | ||
63 | "jns 5f\n" | ||
64 | "2:\t" | ||
65 | "testl $0x200, %[flags]\n\t" | ||
66 | "jz 4f\n\t" | ||
67 | STI_STRING "\n" | ||
68 | "3:\t" | ||
69 | "rep;nop\n\t" | ||
70 | "cmpb $0, %[slock]\n\t" | ||
71 | "jle 3b\n\t" | ||
72 | CLI_STRING "\n\t" | ||
73 | "jmp 1b\n" | ||
74 | "4:\t" | ||
75 | "rep;nop\n\t" | ||
76 | "cmpb $0, %[slock]\n\t" | ||
77 | "jg 1b\n\t" | ||
78 | "jmp 4b\n" | ||
79 | "5:\n\t" | ||
80 | : [slock] "+m" (lock->slock) | ||
81 | : [flags] "r" (flags) | ||
82 | CLI_STI_INPUT_ARGS | ||
83 | : "memory" CLI_STI_CLOBBERS); | ||
84 | } | ||
85 | #endif | ||
86 | |||
87 | static inline int __raw_spin_trylock(raw_spinlock_t *lock) | ||
88 | { | ||
89 | char oldval; | ||
90 | asm volatile( | ||
91 | "xchgb %b0,%1" | ||
92 | :"=q" (oldval), "+m" (lock->slock) | ||
93 | :"0" (0) : "memory"); | ||
94 | return oldval > 0; | ||
95 | } | ||
96 | |||
97 | /* | ||
98 | * __raw_spin_unlock based on writing $1 to the low byte. | ||
99 | * This method works. Despite all the confusion. | ||
100 | * (except on PPro SMP or if we are using OOSTORE, so we use xchgb there) | ||
101 | * (PPro errata 66, 92) | ||
102 | */ | ||
103 | |||
104 | #if !defined(CONFIG_X86_OOSTORE) && !defined(CONFIG_X86_PPRO_FENCE) | ||
105 | |||
106 | static inline void __raw_spin_unlock(raw_spinlock_t *lock) | ||
107 | { | ||
108 | asm volatile("movb $1,%0" : "+m" (lock->slock) :: "memory"); | ||
109 | } | ||
110 | |||
111 | #else | ||
112 | |||
113 | static inline void __raw_spin_unlock(raw_spinlock_t *lock) | ||
114 | { | ||
115 | char oldval = 1; | ||
116 | |||
117 | asm volatile("xchgb %b0, %1" | ||
118 | : "=q" (oldval), "+m" (lock->slock) | ||
119 | : "0" (oldval) : "memory"); | ||
120 | } | ||
121 | |||
122 | #endif | ||
123 | |||
124 | static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock) | ||
125 | { | ||
126 | while (__raw_spin_is_locked(lock)) | ||
127 | cpu_relax(); | ||
128 | } | ||
129 | |||
130 | /* | ||
131 | * Read-write spinlocks, allowing multiple readers | ||
132 | * but only one writer. | ||
133 | * | ||
134 | * NOTE! it is quite common to have readers in interrupts | ||
135 | * but no interrupt writers. For those circumstances we | ||
136 | * can "mix" irq-safe locks - any writer needs to get a | ||
137 | * irq-safe write-lock, but readers can get non-irqsafe | ||
138 | * read-locks. | ||
139 | * | ||
140 | * On x86, we implement read-write locks as a 32-bit counter | ||
141 | * with the high bit (sign) being the "contended" bit. | ||
142 | * | ||
143 | * The inline assembly is non-obvious. Think about it. | ||
144 | * | ||
145 | * Changed to use the same technique as rw semaphores. See | ||
146 | * semaphore.h for details. -ben | ||
147 | * | ||
148 | * the helpers are in arch/i386/kernel/semaphore.c | ||
149 | */ | ||
150 | |||
151 | /** | ||
152 | * read_can_lock - would read_trylock() succeed? | ||
153 | * @lock: the rwlock in question. | ||
154 | */ | ||
155 | static inline int __raw_read_can_lock(raw_rwlock_t *x) | ||
156 | { | ||
157 | return (int)(x)->lock > 0; | ||
158 | } | ||
159 | |||
160 | /** | ||
161 | * write_can_lock - would write_trylock() succeed? | ||
162 | * @lock: the rwlock in question. | ||
163 | */ | ||
164 | static inline int __raw_write_can_lock(raw_rwlock_t *x) | ||
165 | { | ||
166 | return (x)->lock == RW_LOCK_BIAS; | ||
167 | } | ||
168 | |||
169 | static inline void __raw_read_lock(raw_rwlock_t *rw) | ||
170 | { | ||
171 | asm volatile(LOCK_PREFIX " subl $1,(%0)\n\t" | ||
172 | "jns 1f\n" | ||
173 | "call __read_lock_failed\n\t" | ||
174 | "1:\n" | ||
175 | ::"a" (rw) : "memory"); | ||
176 | } | ||
177 | |||
178 | static inline void __raw_write_lock(raw_rwlock_t *rw) | ||
179 | { | ||
180 | asm volatile(LOCK_PREFIX " subl $" RW_LOCK_BIAS_STR ",(%0)\n\t" | ||
181 | "jz 1f\n" | ||
182 | "call __write_lock_failed\n\t" | ||
183 | "1:\n" | ||
184 | ::"a" (rw) : "memory"); | ||
185 | } | ||
186 | |||
187 | static inline int __raw_read_trylock(raw_rwlock_t *lock) | ||
188 | { | ||
189 | atomic_t *count = (atomic_t *)lock; | ||
190 | atomic_dec(count); | ||
191 | if (atomic_read(count) >= 0) | ||
192 | return 1; | ||
193 | atomic_inc(count); | ||
194 | return 0; | ||
195 | } | ||
196 | |||
197 | static inline int __raw_write_trylock(raw_rwlock_t *lock) | ||
198 | { | ||
199 | atomic_t *count = (atomic_t *)lock; | ||
200 | if (atomic_sub_and_test(RW_LOCK_BIAS, count)) | ||
201 | return 1; | ||
202 | atomic_add(RW_LOCK_BIAS, count); | ||
203 | return 0; | ||
204 | } | ||
205 | |||
206 | static inline void __raw_read_unlock(raw_rwlock_t *rw) | ||
207 | { | ||
208 | asm volatile(LOCK_PREFIX "incl %0" :"+m" (rw->lock) : : "memory"); | ||
209 | } | ||
210 | |||
211 | static inline void __raw_write_unlock(raw_rwlock_t *rw) | ||
212 | { | ||
213 | asm volatile(LOCK_PREFIX "addl $" RW_LOCK_BIAS_STR ", %0" | ||
214 | : "+m" (rw->lock) : : "memory"); | ||
215 | } | ||
216 | |||
217 | #define _raw_spin_relax(lock) cpu_relax() | ||
218 | #define _raw_read_relax(lock) cpu_relax() | ||
219 | #define _raw_write_relax(lock) cpu_relax() | ||
220 | |||
221 | #endif /* __ASM_SPINLOCK_H */ | ||