1b8b572e1SStephen Rothwell #ifndef __ASM_SPINLOCK_H 2b8b572e1SStephen Rothwell #define __ASM_SPINLOCK_H 3b8b572e1SStephen Rothwell #ifdef __KERNEL__ 4b8b572e1SStephen Rothwell 5b8b572e1SStephen Rothwell /* 6b8b572e1SStephen Rothwell * Simple spin lock operations. 7b8b572e1SStephen Rothwell * 8b8b572e1SStephen Rothwell * Copyright (C) 2001-2004 Paul Mackerras <paulus@au.ibm.com>, IBM 9b8b572e1SStephen Rothwell * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM 10b8b572e1SStephen Rothwell * Copyright (C) 2002 Dave Engebretsen <engebret@us.ibm.com>, IBM 11b8b572e1SStephen Rothwell * Rework to support virtual processors 12b8b572e1SStephen Rothwell * 13b8b572e1SStephen Rothwell * Type of int is used as a full 64b word is not necessary. 14b8b572e1SStephen Rothwell * 15b8b572e1SStephen Rothwell * This program is free software; you can redistribute it and/or 16b8b572e1SStephen Rothwell * modify it under the terms of the GNU General Public License 17b8b572e1SStephen Rothwell * as published by the Free Software Foundation; either version 18b8b572e1SStephen Rothwell * 2 of the License, or (at your option) any later version. 19b8b572e1SStephen Rothwell * 20b8b572e1SStephen Rothwell * (the type definitions are in asm/spinlock_types.h) 21b8b572e1SStephen Rothwell */ 22b8b572e1SStephen Rothwell #include <linux/irqflags.h> 23b8b572e1SStephen Rothwell #ifdef CONFIG_PPC64 24b8b572e1SStephen Rothwell #include <asm/paca.h> 25b8b572e1SStephen Rothwell #include <asm/hvcall.h> 26b8b572e1SStephen Rothwell #include <asm/iseries/hv_call.h> 27b8b572e1SStephen Rothwell #endif 28b8b572e1SStephen Rothwell #include <asm/asm-compat.h> 29b8b572e1SStephen Rothwell #include <asm/synch.h> 304e14a4d1SAnton Blanchard #include <asm/ppc-opcode.h> 31b8b572e1SStephen Rothwell 320199c4e6SThomas Gleixner #define arch_spin_is_locked(x) ((x)->slock != 0) 33b8b572e1SStephen Rothwell 34b8b572e1SStephen Rothwell #ifdef CONFIG_PPC64 35b8b572e1SStephen Rothwell /* use 0x800000yy when locked, where yy == CPU number */ 36b8b572e1SStephen Rothwell #define LOCK_TOKEN (*(u32 *)(&get_paca()->lock_token)) 37b8b572e1SStephen Rothwell #else 38b8b572e1SStephen Rothwell #define LOCK_TOKEN 1 39b8b572e1SStephen Rothwell #endif 40b8b572e1SStephen Rothwell 41b8b572e1SStephen Rothwell #if defined(CONFIG_PPC64) && defined(CONFIG_SMP) 42b8b572e1SStephen Rothwell #define CLEAR_IO_SYNC (get_paca()->io_sync = 0) 43b8b572e1SStephen Rothwell #define SYNC_IO do { \ 44b8b572e1SStephen Rothwell if (unlikely(get_paca()->io_sync)) { \ 45b8b572e1SStephen Rothwell mb(); \ 46b8b572e1SStephen Rothwell get_paca()->io_sync = 0; \ 47b8b572e1SStephen Rothwell } \ 48b8b572e1SStephen Rothwell } while (0) 49b8b572e1SStephen Rothwell #else 50b8b572e1SStephen Rothwell #define CLEAR_IO_SYNC 51b8b572e1SStephen Rothwell #define SYNC_IO 52b8b572e1SStephen Rothwell #endif 53b8b572e1SStephen Rothwell 54b8b572e1SStephen Rothwell /* 55b8b572e1SStephen Rothwell * This returns the old value in the lock, so we succeeded 56b8b572e1SStephen Rothwell * in getting the lock if the return value is 0. 57b8b572e1SStephen Rothwell */ 580199c4e6SThomas Gleixner static inline unsigned long __arch_spin_trylock(arch_spinlock_t *lock) 59b8b572e1SStephen Rothwell { 60b8b572e1SStephen Rothwell unsigned long tmp, token; 61b8b572e1SStephen Rothwell 62b8b572e1SStephen Rothwell token = LOCK_TOKEN; 63b8b572e1SStephen Rothwell __asm__ __volatile__( 644e14a4d1SAnton Blanchard "1: " PPC_LWARX(%0,0,%2,1) "\n\ 65b8b572e1SStephen Rothwell cmpwi 0,%0,0\n\ 66b8b572e1SStephen Rothwell bne- 2f\n\ 67b8b572e1SStephen Rothwell stwcx. %1,0,%2\n\ 68f10e2e5bSAnton Blanchard bne- 1b\n" 69f10e2e5bSAnton Blanchard PPC_ACQUIRE_BARRIER 70f10e2e5bSAnton Blanchard "2:" 71f10e2e5bSAnton Blanchard : "=&r" (tmp) 72b8b572e1SStephen Rothwell : "r" (token), "r" (&lock->slock) 73b8b572e1SStephen Rothwell : "cr0", "memory"); 74b8b572e1SStephen Rothwell 75b8b572e1SStephen Rothwell return tmp; 76b8b572e1SStephen Rothwell } 77b8b572e1SStephen Rothwell 780199c4e6SThomas Gleixner static inline int arch_spin_trylock(arch_spinlock_t *lock) 79b8b572e1SStephen Rothwell { 80b8b572e1SStephen Rothwell CLEAR_IO_SYNC; 810199c4e6SThomas Gleixner return __arch_spin_trylock(lock) == 0; 82b8b572e1SStephen Rothwell } 83b8b572e1SStephen Rothwell 84b8b572e1SStephen Rothwell /* 85b8b572e1SStephen Rothwell * On a system with shared processors (that is, where a physical 86b8b572e1SStephen Rothwell * processor is multiplexed between several virtual processors), 87b8b572e1SStephen Rothwell * there is no point spinning on a lock if the holder of the lock 88b8b572e1SStephen Rothwell * isn't currently scheduled on a physical processor. Instead 89b8b572e1SStephen Rothwell * we detect this situation and ask the hypervisor to give the 90b8b572e1SStephen Rothwell * rest of our timeslice to the lock holder. 91b8b572e1SStephen Rothwell * 92b8b572e1SStephen Rothwell * So that we can tell which virtual processor is holding a lock, 93b8b572e1SStephen Rothwell * we put 0x80000000 | smp_processor_id() in the lock when it is 94b8b572e1SStephen Rothwell * held. Conveniently, we have a word in the paca that holds this 95b8b572e1SStephen Rothwell * value. 96b8b572e1SStephen Rothwell */ 97b8b572e1SStephen Rothwell 98b8b572e1SStephen Rothwell #if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES) 99b8b572e1SStephen Rothwell /* We only yield to the hypervisor if we are in shared processor mode */ 100b8b572e1SStephen Rothwell #define SHARED_PROCESSOR (get_lppaca()->shared_proc) 101445c8951SThomas Gleixner extern void __spin_yield(arch_spinlock_t *lock); 102fb3a6bbcSThomas Gleixner extern void __rw_yield(arch_rwlock_t *lock); 103b8b572e1SStephen Rothwell #else /* SPLPAR || ISERIES */ 104b8b572e1SStephen Rothwell #define __spin_yield(x) barrier() 105b8b572e1SStephen Rothwell #define __rw_yield(x) barrier() 106b8b572e1SStephen Rothwell #define SHARED_PROCESSOR 0 107b8b572e1SStephen Rothwell #endif 108b8b572e1SStephen Rothwell 1090199c4e6SThomas Gleixner static inline void arch_spin_lock(arch_spinlock_t *lock) 110b8b572e1SStephen Rothwell { 111b8b572e1SStephen Rothwell CLEAR_IO_SYNC; 112b8b572e1SStephen Rothwell while (1) { 1130199c4e6SThomas Gleixner if (likely(__arch_spin_trylock(lock) == 0)) 114b8b572e1SStephen Rothwell break; 115b8b572e1SStephen Rothwell do { 116b8b572e1SStephen Rothwell HMT_low(); 117b8b572e1SStephen Rothwell if (SHARED_PROCESSOR) 118b8b572e1SStephen Rothwell __spin_yield(lock); 119b8b572e1SStephen Rothwell } while (unlikely(lock->slock != 0)); 120b8b572e1SStephen Rothwell HMT_medium(); 121b8b572e1SStephen Rothwell } 122b8b572e1SStephen Rothwell } 123b8b572e1SStephen Rothwell 124b8b572e1SStephen Rothwell static inline 1250199c4e6SThomas Gleixner void arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags) 126b8b572e1SStephen Rothwell { 127b8b572e1SStephen Rothwell unsigned long flags_dis; 128b8b572e1SStephen Rothwell 129b8b572e1SStephen Rothwell CLEAR_IO_SYNC; 130b8b572e1SStephen Rothwell while (1) { 1310199c4e6SThomas Gleixner if (likely(__arch_spin_trylock(lock) == 0)) 132b8b572e1SStephen Rothwell break; 133b8b572e1SStephen Rothwell local_save_flags(flags_dis); 134b8b572e1SStephen Rothwell local_irq_restore(flags); 135b8b572e1SStephen Rothwell do { 136b8b572e1SStephen Rothwell HMT_low(); 137b8b572e1SStephen Rothwell if (SHARED_PROCESSOR) 138b8b572e1SStephen Rothwell __spin_yield(lock); 139b8b572e1SStephen Rothwell } while (unlikely(lock->slock != 0)); 140b8b572e1SStephen Rothwell HMT_medium(); 141b8b572e1SStephen Rothwell local_irq_restore(flags_dis); 142b8b572e1SStephen Rothwell } 143b8b572e1SStephen Rothwell } 144b8b572e1SStephen Rothwell 1450199c4e6SThomas Gleixner static inline void arch_spin_unlock(arch_spinlock_t *lock) 146b8b572e1SStephen Rothwell { 147b8b572e1SStephen Rothwell SYNC_IO; 1480199c4e6SThomas Gleixner __asm__ __volatile__("# arch_spin_unlock\n\t" 149f10e2e5bSAnton Blanchard PPC_RELEASE_BARRIER: : :"memory"); 150b8b572e1SStephen Rothwell lock->slock = 0; 151b8b572e1SStephen Rothwell } 152b8b572e1SStephen Rothwell 153b8b572e1SStephen Rothwell #ifdef CONFIG_PPC64 1540199c4e6SThomas Gleixner extern void arch_spin_unlock_wait(arch_spinlock_t *lock); 155b8b572e1SStephen Rothwell #else 1560199c4e6SThomas Gleixner #define arch_spin_unlock_wait(lock) \ 1570199c4e6SThomas Gleixner do { while (arch_spin_is_locked(lock)) cpu_relax(); } while (0) 158b8b572e1SStephen Rothwell #endif 159b8b572e1SStephen Rothwell 160b8b572e1SStephen Rothwell /* 161b8b572e1SStephen Rothwell * Read-write spinlocks, allowing multiple readers 162b8b572e1SStephen Rothwell * but only one writer. 163b8b572e1SStephen Rothwell * 164b8b572e1SStephen Rothwell * NOTE! it is quite common to have readers in interrupts 165b8b572e1SStephen Rothwell * but no interrupt writers. For those circumstances we 166b8b572e1SStephen Rothwell * can "mix" irq-safe locks - any writer needs to get a 167b8b572e1SStephen Rothwell * irq-safe write-lock, but readers can get non-irqsafe 168b8b572e1SStephen Rothwell * read-locks. 169b8b572e1SStephen Rothwell */ 170b8b572e1SStephen Rothwell 171e5931943SThomas Gleixner #define arch_read_can_lock(rw) ((rw)->lock >= 0) 172e5931943SThomas Gleixner #define arch_write_can_lock(rw) (!(rw)->lock) 173b8b572e1SStephen Rothwell 174b8b572e1SStephen Rothwell #ifdef CONFIG_PPC64 175b8b572e1SStephen Rothwell #define __DO_SIGN_EXTEND "extsw %0,%0\n" 176b8b572e1SStephen Rothwell #define WRLOCK_TOKEN LOCK_TOKEN /* it's negative */ 177b8b572e1SStephen Rothwell #else 178b8b572e1SStephen Rothwell #define __DO_SIGN_EXTEND 179b8b572e1SStephen Rothwell #define WRLOCK_TOKEN (-1) 180b8b572e1SStephen Rothwell #endif 181b8b572e1SStephen Rothwell 182b8b572e1SStephen Rothwell /* 183b8b572e1SStephen Rothwell * This returns the old value in the lock + 1, 184b8b572e1SStephen Rothwell * so we got a read lock if the return value is > 0. 185b8b572e1SStephen Rothwell */ 186e5931943SThomas Gleixner static inline long __arch_read_trylock(arch_rwlock_t *rw) 187b8b572e1SStephen Rothwell { 188b8b572e1SStephen Rothwell long tmp; 189b8b572e1SStephen Rothwell 190b8b572e1SStephen Rothwell __asm__ __volatile__( 1914e14a4d1SAnton Blanchard "1: " PPC_LWARX(%0,0,%1,1) "\n" 192b8b572e1SStephen Rothwell __DO_SIGN_EXTEND 193b8b572e1SStephen Rothwell " addic. %0,%0,1\n\ 194b8b572e1SStephen Rothwell ble- 2f\n" 195b8b572e1SStephen Rothwell PPC405_ERR77(0,%1) 196b8b572e1SStephen Rothwell " stwcx. %0,0,%1\n\ 197f10e2e5bSAnton Blanchard bne- 1b\n" 198f10e2e5bSAnton Blanchard PPC_ACQUIRE_BARRIER 199f10e2e5bSAnton Blanchard "2:" : "=&r" (tmp) 200b8b572e1SStephen Rothwell : "r" (&rw->lock) 201b8b572e1SStephen Rothwell : "cr0", "xer", "memory"); 202b8b572e1SStephen Rothwell 203b8b572e1SStephen Rothwell return tmp; 204b8b572e1SStephen Rothwell } 205b8b572e1SStephen Rothwell 206b8b572e1SStephen Rothwell /* 207b8b572e1SStephen Rothwell * This returns the old value in the lock, 208b8b572e1SStephen Rothwell * so we got the write lock if the return value is 0. 209b8b572e1SStephen Rothwell */ 210e5931943SThomas Gleixner static inline long __arch_write_trylock(arch_rwlock_t *rw) 211b8b572e1SStephen Rothwell { 212b8b572e1SStephen Rothwell long tmp, token; 213b8b572e1SStephen Rothwell 214b8b572e1SStephen Rothwell token = WRLOCK_TOKEN; 215b8b572e1SStephen Rothwell __asm__ __volatile__( 2164e14a4d1SAnton Blanchard "1: " PPC_LWARX(%0,0,%2,1) "\n\ 217b8b572e1SStephen Rothwell cmpwi 0,%0,0\n\ 218b8b572e1SStephen Rothwell bne- 2f\n" 219b8b572e1SStephen Rothwell PPC405_ERR77(0,%1) 220b8b572e1SStephen Rothwell " stwcx. %1,0,%2\n\ 221f10e2e5bSAnton Blanchard bne- 1b\n" 222f10e2e5bSAnton Blanchard PPC_ACQUIRE_BARRIER 223f10e2e5bSAnton Blanchard "2:" : "=&r" (tmp) 224b8b572e1SStephen Rothwell : "r" (token), "r" (&rw->lock) 225b8b572e1SStephen Rothwell : "cr0", "memory"); 226b8b572e1SStephen Rothwell 227b8b572e1SStephen Rothwell return tmp; 228b8b572e1SStephen Rothwell } 229b8b572e1SStephen Rothwell 230e5931943SThomas Gleixner static inline void arch_read_lock(arch_rwlock_t *rw) 231b8b572e1SStephen Rothwell { 232b8b572e1SStephen Rothwell while (1) { 233e5931943SThomas Gleixner if (likely(__arch_read_trylock(rw) > 0)) 234b8b572e1SStephen Rothwell break; 235b8b572e1SStephen Rothwell do { 236b8b572e1SStephen Rothwell HMT_low(); 237b8b572e1SStephen Rothwell if (SHARED_PROCESSOR) 238b8b572e1SStephen Rothwell __rw_yield(rw); 239b8b572e1SStephen Rothwell } while (unlikely(rw->lock < 0)); 240b8b572e1SStephen Rothwell HMT_medium(); 241b8b572e1SStephen Rothwell } 242b8b572e1SStephen Rothwell } 243b8b572e1SStephen Rothwell 244e5931943SThomas Gleixner static inline void arch_write_lock(arch_rwlock_t *rw) 245b8b572e1SStephen Rothwell { 246b8b572e1SStephen Rothwell while (1) { 247e5931943SThomas Gleixner if (likely(__arch_write_trylock(rw) == 0)) 248b8b572e1SStephen Rothwell break; 249b8b572e1SStephen Rothwell do { 250b8b572e1SStephen Rothwell HMT_low(); 251b8b572e1SStephen Rothwell if (SHARED_PROCESSOR) 252b8b572e1SStephen Rothwell __rw_yield(rw); 253b8b572e1SStephen Rothwell } while (unlikely(rw->lock != 0)); 254b8b572e1SStephen Rothwell HMT_medium(); 255b8b572e1SStephen Rothwell } 256b8b572e1SStephen Rothwell } 257b8b572e1SStephen Rothwell 258e5931943SThomas Gleixner static inline int arch_read_trylock(arch_rwlock_t *rw) 259b8b572e1SStephen Rothwell { 260e5931943SThomas Gleixner return __arch_read_trylock(rw) > 0; 261b8b572e1SStephen Rothwell } 262b8b572e1SStephen Rothwell 263e5931943SThomas Gleixner static inline int arch_write_trylock(arch_rwlock_t *rw) 264b8b572e1SStephen Rothwell { 265e5931943SThomas Gleixner return __arch_write_trylock(rw) == 0; 266b8b572e1SStephen Rothwell } 267b8b572e1SStephen Rothwell 268e5931943SThomas Gleixner static inline void arch_read_unlock(arch_rwlock_t *rw) 269b8b572e1SStephen Rothwell { 270b8b572e1SStephen Rothwell long tmp; 271b8b572e1SStephen Rothwell 272b8b572e1SStephen Rothwell __asm__ __volatile__( 273b8b572e1SStephen Rothwell "# read_unlock\n\t" 274f10e2e5bSAnton Blanchard PPC_RELEASE_BARRIER 275b8b572e1SStephen Rothwell "1: lwarx %0,0,%1\n\ 276b8b572e1SStephen Rothwell addic %0,%0,-1\n" 277b8b572e1SStephen Rothwell PPC405_ERR77(0,%1) 278b8b572e1SStephen Rothwell " stwcx. %0,0,%1\n\ 279b8b572e1SStephen Rothwell bne- 1b" 280b8b572e1SStephen Rothwell : "=&r"(tmp) 281b8b572e1SStephen Rothwell : "r"(&rw->lock) 282efc3624cSPaul Mackerras : "cr0", "xer", "memory"); 283b8b572e1SStephen Rothwell } 284b8b572e1SStephen Rothwell 285e5931943SThomas Gleixner static inline void arch_write_unlock(arch_rwlock_t *rw) 286b8b572e1SStephen Rothwell { 287b8b572e1SStephen Rothwell __asm__ __volatile__("# write_unlock\n\t" 288f10e2e5bSAnton Blanchard PPC_RELEASE_BARRIER: : :"memory"); 289b8b572e1SStephen Rothwell rw->lock = 0; 290b8b572e1SStephen Rothwell } 291b8b572e1SStephen Rothwell 292e5931943SThomas Gleixner #define arch_read_lock_flags(lock, flags) arch_read_lock(lock) 293e5931943SThomas Gleixner #define arch_write_lock_flags(lock, flags) arch_write_lock(lock) 294f5f7eac4SRobin Holt 2950199c4e6SThomas Gleixner #define arch_spin_relax(lock) __spin_yield(lock) 2960199c4e6SThomas Gleixner #define arch_read_relax(lock) __rw_yield(lock) 2970199c4e6SThomas Gleixner #define arch_write_relax(lock) __rw_yield(lock) 298b8b572e1SStephen Rothwell 299b8b572e1SStephen Rothwell #endif /* __KERNEL__ */ 300b8b572e1SStephen Rothwell #endif /* __ASM_SPINLOCK_H */ 301