Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | #ifndef __ASM_SPINLOCK_H |
| 2 | #define __ASM_SPINLOCK_H |
Arnd Bergmann | 88ced03 | 2005-12-16 22:43:46 +0100 | [diff] [blame] | 3 | #ifdef __KERNEL__ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4 | |
| 5 | /* |
| 6 | * Simple spin lock operations. |
| 7 | * |
| 8 | * Copyright (C) 2001-2004 Paul Mackerras <paulus@au.ibm.com>, IBM |
| 9 | * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM |
| 10 | * Copyright (C) 2002 Dave Engebretsen <engebret@us.ibm.com>, IBM |
| 11 | * Rework to support virtual processors |
| 12 | * |
| 13 | * Type of int is used as a full 64b word is not necessary. |
| 14 | * |
| 15 | * This program is free software; you can redistribute it and/or |
| 16 | * modify it under the terms of the GNU General Public License |
| 17 | * as published by the Free Software Foundation; either version |
| 18 | * 2 of the License, or (at your option) any later version. |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 19 | * |
| 20 | * (the type definitions are in asm/spinlock_types.h) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 21 | */ |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 22 | #ifdef CONFIG_PPC64 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | #include <asm/paca.h> |
| 24 | #include <asm/hvcall.h> |
Kelly Daly | 1da4403 | 2005-11-01 16:59:20 +1100 | [diff] [blame] | 25 | #include <asm/iseries/hv_call.h> |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 26 | #endif |
| 27 | #include <asm/asm-compat.h> |
| 28 | #include <asm/synch.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 30 | #define __raw_spin_is_locked(x) ((x)->slock != 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 32 | #ifdef CONFIG_PPC64 |
| 33 | /* use 0x800000yy when locked, where yy == CPU number */ |
| 34 | #define LOCK_TOKEN (*(u32 *)(&get_paca()->lock_token)) |
| 35 | #else |
| 36 | #define LOCK_TOKEN 1 |
| 37 | #endif |
| 38 | |
Paul Mackerras | f007cac | 2006-09-13 22:08:26 +1000 | [diff] [blame] | 39 | #if defined(CONFIG_PPC64) && defined(CONFIG_SMP) |
| 40 | #define CLEAR_IO_SYNC (get_paca()->io_sync = 0) |
| 41 | #define SYNC_IO do { \ |
| 42 | if (unlikely(get_paca()->io_sync)) { \ |
| 43 | mb(); \ |
| 44 | get_paca()->io_sync = 0; \ |
| 45 | } \ |
| 46 | } while (0) |
| 47 | #else |
| 48 | #define CLEAR_IO_SYNC |
| 49 | #define SYNC_IO |
| 50 | #endif |
| 51 | |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 52 | /* |
| 53 | * This returns the old value in the lock, so we succeeded |
| 54 | * in getting the lock if the return value is 0. |
| 55 | */ |
| 56 | static __inline__ unsigned long __spin_trylock(raw_spinlock_t *lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 57 | { |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 58 | unsigned long tmp, token; |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 59 | |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 60 | token = LOCK_TOKEN; |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 61 | __asm__ __volatile__( |
Anton Blanchard | 144b9c1 | 2006-01-13 15:37:17 +1100 | [diff] [blame] | 62 | "1: lwarx %0,0,%2\n\ |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 63 | cmpwi 0,%0,0\n\ |
| 64 | bne- 2f\n\ |
| 65 | stwcx. %1,0,%2\n\ |
| 66 | bne- 1b\n\ |
| 67 | isync\n\ |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 68 | 2:" : "=&r" (tmp) |
| 69 | : "r" (token), "r" (&lock->slock) |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 70 | : "cr0", "memory"); |
| 71 | |
| 72 | return tmp; |
| 73 | } |
| 74 | |
| 75 | static int __inline__ __raw_spin_trylock(raw_spinlock_t *lock) |
| 76 | { |
Paul Mackerras | f007cac | 2006-09-13 22:08:26 +1000 | [diff] [blame] | 77 | CLEAR_IO_SYNC; |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 78 | return __spin_trylock(lock) == 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | } |
| 80 | |
| 81 | /* |
| 82 | * On a system with shared processors (that is, where a physical |
| 83 | * processor is multiplexed between several virtual processors), |
| 84 | * there is no point spinning on a lock if the holder of the lock |
| 85 | * isn't currently scheduled on a physical processor. Instead |
| 86 | * we detect this situation and ask the hypervisor to give the |
| 87 | * rest of our timeslice to the lock holder. |
| 88 | * |
| 89 | * So that we can tell which virtual processor is holding a lock, |
| 90 | * we put 0x80000000 | smp_processor_id() in the lock when it is |
| 91 | * held. Conveniently, we have a word in the paca that holds this |
| 92 | * value. |
| 93 | */ |
| 94 | |
| 95 | #if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES) |
| 96 | /* We only yield to the hypervisor if we are in shared processor mode */ |
David Gibson | 3356bb9f7 | 2006-01-13 10:26:42 +1100 | [diff] [blame] | 97 | #define SHARED_PROCESSOR (get_lppaca()->shared_proc) |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 98 | extern void __spin_yield(raw_spinlock_t *lock); |
| 99 | extern void __rw_yield(raw_rwlock_t *lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 100 | #else /* SPLPAR || ISERIES */ |
| 101 | #define __spin_yield(x) barrier() |
| 102 | #define __rw_yield(x) barrier() |
| 103 | #define SHARED_PROCESSOR 0 |
| 104 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 105 | |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 106 | static void __inline__ __raw_spin_lock(raw_spinlock_t *lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 107 | { |
Paul Mackerras | f007cac | 2006-09-13 22:08:26 +1000 | [diff] [blame] | 108 | CLEAR_IO_SYNC; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 109 | while (1) { |
| 110 | if (likely(__spin_trylock(lock) == 0)) |
| 111 | break; |
| 112 | do { |
| 113 | HMT_low(); |
| 114 | if (SHARED_PROCESSOR) |
| 115 | __spin_yield(lock); |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 116 | } while (unlikely(lock->slock != 0)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | HMT_medium(); |
| 118 | } |
| 119 | } |
| 120 | |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 121 | static void __inline__ __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | { |
| 123 | unsigned long flags_dis; |
| 124 | |
Paul Mackerras | f007cac | 2006-09-13 22:08:26 +1000 | [diff] [blame] | 125 | CLEAR_IO_SYNC; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | while (1) { |
| 127 | if (likely(__spin_trylock(lock) == 0)) |
| 128 | break; |
| 129 | local_save_flags(flags_dis); |
| 130 | local_irq_restore(flags); |
| 131 | do { |
| 132 | HMT_low(); |
| 133 | if (SHARED_PROCESSOR) |
| 134 | __spin_yield(lock); |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 135 | } while (unlikely(lock->slock != 0)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 136 | HMT_medium(); |
| 137 | local_irq_restore(flags_dis); |
| 138 | } |
| 139 | } |
| 140 | |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 141 | static __inline__ void __raw_spin_unlock(raw_spinlock_t *lock) |
| 142 | { |
Paul Mackerras | f007cac | 2006-09-13 22:08:26 +1000 | [diff] [blame] | 143 | SYNC_IO; |
Anton Blanchard | 144b9c1 | 2006-01-13 15:37:17 +1100 | [diff] [blame] | 144 | __asm__ __volatile__("# __raw_spin_unlock\n\t" |
| 145 | LWSYNC_ON_SMP: : :"memory"); |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 146 | lock->slock = 0; |
| 147 | } |
| 148 | |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 149 | #ifdef CONFIG_PPC64 |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 150 | extern void __raw_spin_unlock_wait(raw_spinlock_t *lock); |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 151 | #else |
| 152 | #define __raw_spin_unlock_wait(lock) \ |
| 153 | do { while (__raw_spin_is_locked(lock)) cpu_relax(); } while (0) |
| 154 | #endif |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 155 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 156 | /* |
| 157 | * Read-write spinlocks, allowing multiple readers |
| 158 | * but only one writer. |
| 159 | * |
| 160 | * NOTE! it is quite common to have readers in interrupts |
| 161 | * but no interrupt writers. For those circumstances we |
| 162 | * can "mix" irq-safe locks - any writer needs to get a |
| 163 | * irq-safe write-lock, but readers can get non-irqsafe |
| 164 | * read-locks. |
| 165 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 167 | #define __raw_read_can_lock(rw) ((rw)->lock >= 0) |
| 168 | #define __raw_write_can_lock(rw) (!(rw)->lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 169 | |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 170 | #ifdef CONFIG_PPC64 |
| 171 | #define __DO_SIGN_EXTEND "extsw %0,%0\n" |
| 172 | #define WRLOCK_TOKEN LOCK_TOKEN /* it's negative */ |
| 173 | #else |
| 174 | #define __DO_SIGN_EXTEND |
| 175 | #define WRLOCK_TOKEN (-1) |
| 176 | #endif |
| 177 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 178 | /* |
| 179 | * This returns the old value in the lock + 1, |
| 180 | * so we got a read lock if the return value is > 0. |
| 181 | */ |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 182 | static long __inline__ __read_trylock(raw_rwlock_t *rw) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 183 | { |
| 184 | long tmp; |
| 185 | |
| 186 | __asm__ __volatile__( |
Anton Blanchard | 144b9c1 | 2006-01-13 15:37:17 +1100 | [diff] [blame] | 187 | "1: lwarx %0,0,%1\n" |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 188 | __DO_SIGN_EXTEND |
| 189 | " addic. %0,%0,1\n\ |
| 190 | ble- 2f\n" |
| 191 | PPC405_ERR77(0,%1) |
| 192 | " stwcx. %0,0,%1\n\ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 193 | bne- 1b\n\ |
| 194 | isync\n\ |
| 195 | 2:" : "=&r" (tmp) |
| 196 | : "r" (&rw->lock) |
| 197 | : "cr0", "xer", "memory"); |
| 198 | |
| 199 | return tmp; |
| 200 | } |
| 201 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | /* |
| 203 | * This returns the old value in the lock, |
| 204 | * so we got the write lock if the return value is 0. |
| 205 | */ |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 206 | static __inline__ long __write_trylock(raw_rwlock_t *rw) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 207 | { |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 208 | long tmp, token; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 209 | |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 210 | token = WRLOCK_TOKEN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 211 | __asm__ __volatile__( |
Anton Blanchard | 144b9c1 | 2006-01-13 15:37:17 +1100 | [diff] [blame] | 212 | "1: lwarx %0,0,%2\n\ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 213 | cmpwi 0,%0,0\n\ |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 214 | bne- 2f\n" |
| 215 | PPC405_ERR77(0,%1) |
| 216 | " stwcx. %1,0,%2\n\ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 217 | bne- 1b\n\ |
| 218 | isync\n\ |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 219 | 2:" : "=&r" (tmp) |
| 220 | : "r" (token), "r" (&rw->lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 221 | : "cr0", "memory"); |
| 222 | |
| 223 | return tmp; |
| 224 | } |
| 225 | |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 226 | static void __inline__ __raw_read_lock(raw_rwlock_t *rw) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 227 | { |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 228 | while (1) { |
| 229 | if (likely(__read_trylock(rw) > 0)) |
| 230 | break; |
| 231 | do { |
| 232 | HMT_low(); |
| 233 | if (SHARED_PROCESSOR) |
| 234 | __rw_yield(rw); |
| 235 | } while (unlikely(rw->lock < 0)); |
| 236 | HMT_medium(); |
| 237 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 238 | } |
| 239 | |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 240 | static void __inline__ __raw_write_lock(raw_rwlock_t *rw) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 241 | { |
| 242 | while (1) { |
| 243 | if (likely(__write_trylock(rw) == 0)) |
| 244 | break; |
| 245 | do { |
| 246 | HMT_low(); |
| 247 | if (SHARED_PROCESSOR) |
| 248 | __rw_yield(rw); |
Jake Moilanen | d637413 | 2005-05-01 08:58:47 -0700 | [diff] [blame] | 249 | } while (unlikely(rw->lock != 0)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 250 | HMT_medium(); |
| 251 | } |
| 252 | } |
| 253 | |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 254 | static int __inline__ __raw_read_trylock(raw_rwlock_t *rw) |
| 255 | { |
| 256 | return __read_trylock(rw) > 0; |
| 257 | } |
| 258 | |
| 259 | static int __inline__ __raw_write_trylock(raw_rwlock_t *rw) |
| 260 | { |
| 261 | return __write_trylock(rw) == 0; |
| 262 | } |
| 263 | |
| 264 | static void __inline__ __raw_read_unlock(raw_rwlock_t *rw) |
| 265 | { |
| 266 | long tmp; |
| 267 | |
| 268 | __asm__ __volatile__( |
Anton Blanchard | 144b9c1 | 2006-01-13 15:37:17 +1100 | [diff] [blame] | 269 | "# read_unlock\n\t" |
| 270 | LWSYNC_ON_SMP |
| 271 | "1: lwarx %0,0,%1\n\ |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 272 | addic %0,%0,-1\n" |
| 273 | PPC405_ERR77(0,%1) |
| 274 | " stwcx. %0,0,%1\n\ |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 275 | bne- 1b" |
| 276 | : "=&r"(tmp) |
| 277 | : "r"(&rw->lock) |
| 278 | : "cr0", "memory"); |
| 279 | } |
| 280 | |
| 281 | static __inline__ void __raw_write_unlock(raw_rwlock_t *rw) |
| 282 | { |
Anton Blanchard | 144b9c1 | 2006-01-13 15:37:17 +1100 | [diff] [blame] | 283 | __asm__ __volatile__("# write_unlock\n\t" |
| 284 | LWSYNC_ON_SMP: : :"memory"); |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 285 | rw->lock = 0; |
| 286 | } |
| 287 | |
Arnd Bergmann | 88ced03 | 2005-12-16 22:43:46 +0100 | [diff] [blame] | 288 | #endif /* __KERNEL__ */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 289 | #endif /* __ASM_SPINLOCK_H */ |