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 | |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 39 | /* |
| 40 | * This returns the old value in the lock, so we succeeded |
| 41 | * in getting the lock if the return value is 0. |
| 42 | */ |
| 43 | static __inline__ unsigned long __spin_trylock(raw_spinlock_t *lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | { |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 45 | unsigned long tmp, token; |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 46 | |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 47 | token = LOCK_TOKEN; |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 48 | __asm__ __volatile__( |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 49 | "1: lwarx %0,0,%2 # __spin_trylock\n\ |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 50 | cmpwi 0,%0,0\n\ |
| 51 | bne- 2f\n\ |
| 52 | stwcx. %1,0,%2\n\ |
| 53 | bne- 1b\n\ |
| 54 | isync\n\ |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 55 | 2:" : "=&r" (tmp) |
| 56 | : "r" (token), "r" (&lock->slock) |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 57 | : "cr0", "memory"); |
| 58 | |
| 59 | return tmp; |
| 60 | } |
| 61 | |
| 62 | static int __inline__ __raw_spin_trylock(raw_spinlock_t *lock) |
| 63 | { |
| 64 | return __spin_trylock(lock) == 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 65 | } |
| 66 | |
| 67 | /* |
| 68 | * On a system with shared processors (that is, where a physical |
| 69 | * processor is multiplexed between several virtual processors), |
| 70 | * there is no point spinning on a lock if the holder of the lock |
| 71 | * isn't currently scheduled on a physical processor. Instead |
| 72 | * we detect this situation and ask the hypervisor to give the |
| 73 | * rest of our timeslice to the lock holder. |
| 74 | * |
| 75 | * So that we can tell which virtual processor is holding a lock, |
| 76 | * we put 0x80000000 | smp_processor_id() in the lock when it is |
| 77 | * held. Conveniently, we have a word in the paca that holds this |
| 78 | * value. |
| 79 | */ |
| 80 | |
| 81 | #if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES) |
| 82 | /* 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^] | 83 | #define SHARED_PROCESSOR (get_lppaca()->shared_proc) |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 84 | extern void __spin_yield(raw_spinlock_t *lock); |
| 85 | extern void __rw_yield(raw_rwlock_t *lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | #else /* SPLPAR || ISERIES */ |
| 87 | #define __spin_yield(x) barrier() |
| 88 | #define __rw_yield(x) barrier() |
| 89 | #define SHARED_PROCESSOR 0 |
| 90 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 91 | |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 92 | static void __inline__ __raw_spin_lock(raw_spinlock_t *lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 93 | { |
| 94 | while (1) { |
| 95 | if (likely(__spin_trylock(lock) == 0)) |
| 96 | break; |
| 97 | do { |
| 98 | HMT_low(); |
| 99 | if (SHARED_PROCESSOR) |
| 100 | __spin_yield(lock); |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 101 | } while (unlikely(lock->slock != 0)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 102 | HMT_medium(); |
| 103 | } |
| 104 | } |
| 105 | |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 106 | 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] | 107 | { |
| 108 | unsigned long flags_dis; |
| 109 | |
| 110 | while (1) { |
| 111 | if (likely(__spin_trylock(lock) == 0)) |
| 112 | break; |
| 113 | local_save_flags(flags_dis); |
| 114 | local_irq_restore(flags); |
| 115 | do { |
| 116 | HMT_low(); |
| 117 | if (SHARED_PROCESSOR) |
| 118 | __spin_yield(lock); |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 119 | } while (unlikely(lock->slock != 0)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | HMT_medium(); |
| 121 | local_irq_restore(flags_dis); |
| 122 | } |
| 123 | } |
| 124 | |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 125 | static __inline__ void __raw_spin_unlock(raw_spinlock_t *lock) |
| 126 | { |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 127 | __asm__ __volatile__(SYNC_ON_SMP" # __raw_spin_unlock" |
| 128 | : : :"memory"); |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 129 | lock->slock = 0; |
| 130 | } |
| 131 | |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 132 | #ifdef CONFIG_PPC64 |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 133 | extern void __raw_spin_unlock_wait(raw_spinlock_t *lock); |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 134 | #else |
| 135 | #define __raw_spin_unlock_wait(lock) \ |
| 136 | do { while (__raw_spin_is_locked(lock)) cpu_relax(); } while (0) |
| 137 | #endif |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 138 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 139 | /* |
| 140 | * Read-write spinlocks, allowing multiple readers |
| 141 | * but only one writer. |
| 142 | * |
| 143 | * NOTE! it is quite common to have readers in interrupts |
| 144 | * but no interrupt writers. For those circumstances we |
| 145 | * can "mix" irq-safe locks - any writer needs to get a |
| 146 | * irq-safe write-lock, but readers can get non-irqsafe |
| 147 | * read-locks. |
| 148 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 149 | |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 150 | #define __raw_read_can_lock(rw) ((rw)->lock >= 0) |
| 151 | #define __raw_write_can_lock(rw) (!(rw)->lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 152 | |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 153 | #ifdef CONFIG_PPC64 |
| 154 | #define __DO_SIGN_EXTEND "extsw %0,%0\n" |
| 155 | #define WRLOCK_TOKEN LOCK_TOKEN /* it's negative */ |
| 156 | #else |
| 157 | #define __DO_SIGN_EXTEND |
| 158 | #define WRLOCK_TOKEN (-1) |
| 159 | #endif |
| 160 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | /* |
| 162 | * This returns the old value in the lock + 1, |
| 163 | * so we got a read lock if the return value is > 0. |
| 164 | */ |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 165 | static long __inline__ __read_trylock(raw_rwlock_t *rw) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | { |
| 167 | long tmp; |
| 168 | |
| 169 | __asm__ __volatile__( |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 170 | "1: lwarx %0,0,%1 # read_trylock\n" |
| 171 | __DO_SIGN_EXTEND |
| 172 | " addic. %0,%0,1\n\ |
| 173 | ble- 2f\n" |
| 174 | PPC405_ERR77(0,%1) |
| 175 | " stwcx. %0,0,%1\n\ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 176 | bne- 1b\n\ |
| 177 | isync\n\ |
| 178 | 2:" : "=&r" (tmp) |
| 179 | : "r" (&rw->lock) |
| 180 | : "cr0", "xer", "memory"); |
| 181 | |
| 182 | return tmp; |
| 183 | } |
| 184 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 185 | /* |
| 186 | * This returns the old value in the lock, |
| 187 | * so we got the write lock if the return value is 0. |
| 188 | */ |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 189 | static __inline__ long __write_trylock(raw_rwlock_t *rw) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 190 | { |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 191 | long tmp, token; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 192 | |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 193 | token = WRLOCK_TOKEN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 194 | __asm__ __volatile__( |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 195 | "1: lwarx %0,0,%2 # write_trylock\n\ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 196 | cmpwi 0,%0,0\n\ |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 197 | bne- 2f\n" |
| 198 | PPC405_ERR77(0,%1) |
| 199 | " stwcx. %1,0,%2\n\ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 200 | bne- 1b\n\ |
| 201 | isync\n\ |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 202 | 2:" : "=&r" (tmp) |
| 203 | : "r" (token), "r" (&rw->lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | : "cr0", "memory"); |
| 205 | |
| 206 | return tmp; |
| 207 | } |
| 208 | |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 209 | static void __inline__ __raw_read_lock(raw_rwlock_t *rw) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 210 | { |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 211 | while (1) { |
| 212 | if (likely(__read_trylock(rw) > 0)) |
| 213 | break; |
| 214 | do { |
| 215 | HMT_low(); |
| 216 | if (SHARED_PROCESSOR) |
| 217 | __rw_yield(rw); |
| 218 | } while (unlikely(rw->lock < 0)); |
| 219 | HMT_medium(); |
| 220 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 221 | } |
| 222 | |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 223 | static void __inline__ __raw_write_lock(raw_rwlock_t *rw) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 224 | { |
| 225 | while (1) { |
| 226 | if (likely(__write_trylock(rw) == 0)) |
| 227 | break; |
| 228 | do { |
| 229 | HMT_low(); |
| 230 | if (SHARED_PROCESSOR) |
| 231 | __rw_yield(rw); |
Jake Moilanen | d637413 | 2005-05-01 08:58:47 -0700 | [diff] [blame] | 232 | } while (unlikely(rw->lock != 0)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 233 | HMT_medium(); |
| 234 | } |
| 235 | } |
| 236 | |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 237 | static int __inline__ __raw_read_trylock(raw_rwlock_t *rw) |
| 238 | { |
| 239 | return __read_trylock(rw) > 0; |
| 240 | } |
| 241 | |
| 242 | static int __inline__ __raw_write_trylock(raw_rwlock_t *rw) |
| 243 | { |
| 244 | return __write_trylock(rw) == 0; |
| 245 | } |
| 246 | |
| 247 | static void __inline__ __raw_read_unlock(raw_rwlock_t *rw) |
| 248 | { |
| 249 | long tmp; |
| 250 | |
| 251 | __asm__ __volatile__( |
| 252 | "eieio # read_unlock\n\ |
| 253 | 1: lwarx %0,0,%1\n\ |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 254 | addic %0,%0,-1\n" |
| 255 | PPC405_ERR77(0,%1) |
| 256 | " stwcx. %0,0,%1\n\ |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 257 | bne- 1b" |
| 258 | : "=&r"(tmp) |
| 259 | : "r"(&rw->lock) |
| 260 | : "cr0", "memory"); |
| 261 | } |
| 262 | |
| 263 | static __inline__ void __raw_write_unlock(raw_rwlock_t *rw) |
| 264 | { |
Paul Mackerras | 0212ddd | 2005-11-19 20:50:46 +1100 | [diff] [blame] | 265 | __asm__ __volatile__(SYNC_ON_SMP" # write_unlock" |
| 266 | : : :"memory"); |
Ingo Molnar | fb1c8f9 | 2005-09-10 00:25:56 -0700 | [diff] [blame] | 267 | rw->lock = 0; |
| 268 | } |
| 269 | |
Arnd Bergmann | 88ced03 | 2005-12-16 22:43:46 +0100 | [diff] [blame] | 270 | #endif /* __KERNEL__ */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 271 | #endif /* __ASM_SPINLOCK_H */ |