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Diffstat (limited to 'include/asm-x86/spinlock.h')
-rw-r--r--include/asm-x86/spinlock.h118
1 files changed, 103 insertions, 15 deletions
diff --git a/include/asm-x86/spinlock.h b/include/asm-x86/spinlock.h
index 21e89bf92f1c..4f9a9861799a 100644
--- a/include/asm-x86/spinlock.h
+++ b/include/asm-x86/spinlock.h
@@ -6,7 +6,7 @@
6#include <asm/page.h> 6#include <asm/page.h>
7#include <asm/processor.h> 7#include <asm/processor.h>
8#include <linux/compiler.h> 8#include <linux/compiler.h>
9 9#include <asm/paravirt.h>
10/* 10/*
11 * Your basic SMP spinlocks, allowing only a single CPU anywhere 11 * Your basic SMP spinlocks, allowing only a single CPU anywhere
12 * 12 *
@@ -54,21 +54,21 @@
54 * much between them in performance though, especially as locks are out of line. 54 * much between them in performance though, especially as locks are out of line.
55 */ 55 */
56#if (NR_CPUS < 256) 56#if (NR_CPUS < 256)
57static inline int __raw_spin_is_locked(raw_spinlock_t *lock) 57static inline int __ticket_spin_is_locked(raw_spinlock_t *lock)
58{ 58{
59 int tmp = ACCESS_ONCE(lock->slock); 59 int tmp = ACCESS_ONCE(lock->slock);
60 60
61 return (((tmp >> 8) & 0xff) != (tmp & 0xff)); 61 return (((tmp >> 8) & 0xff) != (tmp & 0xff));
62} 62}
63 63
64static inline int __raw_spin_is_contended(raw_spinlock_t *lock) 64static inline int __ticket_spin_is_contended(raw_spinlock_t *lock)
65{ 65{
66 int tmp = ACCESS_ONCE(lock->slock); 66 int tmp = ACCESS_ONCE(lock->slock);
67 67
68 return (((tmp >> 8) & 0xff) - (tmp & 0xff)) > 1; 68 return (((tmp >> 8) & 0xff) - (tmp & 0xff)) > 1;
69} 69}
70 70
71static __always_inline void __raw_spin_lock(raw_spinlock_t *lock) 71static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock)
72{ 72{
73 short inc = 0x0100; 73 short inc = 0x0100;
74 74
@@ -87,9 +87,7 @@ static __always_inline void __raw_spin_lock(raw_spinlock_t *lock)
87 : "memory", "cc"); 87 : "memory", "cc");
88} 88}
89 89
90#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock) 90static __always_inline int __ticket_spin_trylock(raw_spinlock_t *lock)
91
92static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock)
93{ 91{
94 int tmp; 92 int tmp;
95 short new; 93 short new;
@@ -110,7 +108,7 @@ static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock)
110 return tmp; 108 return tmp;
111} 109}
112 110
113static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock) 111static __always_inline void __ticket_spin_unlock(raw_spinlock_t *lock)
114{ 112{
115 asm volatile(UNLOCK_LOCK_PREFIX "incb %0" 113 asm volatile(UNLOCK_LOCK_PREFIX "incb %0"
116 : "+m" (lock->slock) 114 : "+m" (lock->slock)
@@ -118,21 +116,21 @@ static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock)
118 : "memory", "cc"); 116 : "memory", "cc");
119} 117}
120#else 118#else
121static inline int __raw_spin_is_locked(raw_spinlock_t *lock) 119static inline int __ticket_spin_is_locked(raw_spinlock_t *lock)
122{ 120{
123 int tmp = ACCESS_ONCE(lock->slock); 121 int tmp = ACCESS_ONCE(lock->slock);
124 122
125 return (((tmp >> 16) & 0xffff) != (tmp & 0xffff)); 123 return (((tmp >> 16) & 0xffff) != (tmp & 0xffff));
126} 124}
127 125
128static inline int __raw_spin_is_contended(raw_spinlock_t *lock) 126static inline int __ticket_spin_is_contended(raw_spinlock_t *lock)
129{ 127{
130 int tmp = ACCESS_ONCE(lock->slock); 128 int tmp = ACCESS_ONCE(lock->slock);
131 129
132 return (((tmp >> 16) & 0xffff) - (tmp & 0xffff)) > 1; 130 return (((tmp >> 16) & 0xffff) - (tmp & 0xffff)) > 1;
133} 131}
134 132
135static __always_inline void __raw_spin_lock(raw_spinlock_t *lock) 133static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock)
136{ 134{
137 int inc = 0x00010000; 135 int inc = 0x00010000;
138 int tmp; 136 int tmp;
@@ -153,9 +151,7 @@ static __always_inline void __raw_spin_lock(raw_spinlock_t *lock)
153 : "memory", "cc"); 151 : "memory", "cc");
154} 152}
155 153
156#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock) 154static __always_inline int __ticket_spin_trylock(raw_spinlock_t *lock)
157
158static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock)
159{ 155{
160 int tmp; 156 int tmp;
161 int new; 157 int new;
@@ -177,7 +173,7 @@ static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock)
177 return tmp; 173 return tmp;
178} 174}
179 175
180static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock) 176static __always_inline void __ticket_spin_unlock(raw_spinlock_t *lock)
181{ 177{
182 asm volatile(UNLOCK_LOCK_PREFIX "incw %0" 178 asm volatile(UNLOCK_LOCK_PREFIX "incw %0"
183 : "+m" (lock->slock) 179 : "+m" (lock->slock)
@@ -186,6 +182,98 @@ static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock)
186} 182}
187#endif 183#endif
188 184
185#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
186
187#ifdef CONFIG_PARAVIRT
188/*
189 * Define virtualization-friendly old-style lock byte lock, for use in
190 * pv_lock_ops if desired.
191 *
192 * This differs from the pre-2.6.24 spinlock by always using xchgb
193 * rather than decb to take the lock; this allows it to use a
194 * zero-initialized lock structure. It also maintains a 1-byte
195 * contention counter, so that we can implement
196 * __byte_spin_is_contended.
197 */
198struct __byte_spinlock {
199 s8 lock;
200 s8 spinners;
201};
202
203static inline int __byte_spin_is_locked(raw_spinlock_t *lock)
204{
205 struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
206 return bl->lock != 0;
207}
208
209static inline int __byte_spin_is_contended(raw_spinlock_t *lock)
210{
211 struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
212 return bl->spinners != 0;
213}
214
215static inline void __byte_spin_lock(raw_spinlock_t *lock)
216{
217 struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
218 s8 val = 1;
219
220 asm("1: xchgb %1, %0\n"
221 " test %1,%1\n"
222 " jz 3f\n"
223 " " LOCK_PREFIX "incb %2\n"
224 "2: rep;nop\n"
225 " cmpb $1, %0\n"
226 " je 2b\n"
227 " " LOCK_PREFIX "decb %2\n"
228 " jmp 1b\n"
229 "3:"
230 : "+m" (bl->lock), "+q" (val), "+m" (bl->spinners): : "memory");
231}
232
233static inline int __byte_spin_trylock(raw_spinlock_t *lock)
234{
235 struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
236 u8 old = 1;
237
238 asm("xchgb %1,%0"
239 : "+m" (bl->lock), "+q" (old) : : "memory");
240
241 return old == 0;
242}
243
244static inline void __byte_spin_unlock(raw_spinlock_t *lock)
245{
246 struct __byte_spinlock *bl = (struct __byte_spinlock *)lock;
247 smp_wmb();
248 bl->lock = 0;
249}
250#else /* !CONFIG_PARAVIRT */
251static inline int __raw_spin_is_locked(raw_spinlock_t *lock)
252{
253 return __ticket_spin_is_locked(lock);
254}
255
256static inline int __raw_spin_is_contended(raw_spinlock_t *lock)
257{
258 return __ticket_spin_is_contended(lock);
259}
260
261static __always_inline void __raw_spin_lock(raw_spinlock_t *lock)
262{
263 __ticket_spin_lock(lock);
264}
265
266static __always_inline int __raw_spin_trylock(raw_spinlock_t *lock)
267{
268 return __ticket_spin_trylock(lock);
269}
270
271static __always_inline void __raw_spin_unlock(raw_spinlock_t *lock)
272{
273 __ticket_spin_unlock(lock);
274}
275#endif /* CONFIG_PARAVIRT */
276
189static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock) 277static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock)
190{ 278{
191 while (__raw_spin_is_locked(lock)) 279 while (__raw_spin_is_locked(lock))