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 #endif 27b8b572e1SStephen Rothwell #include <asm/asm-compat.h> 28b8b572e1SStephen Rothwell #include <asm/synch.h> 294e14a4d1SAnton Blanchard #include <asm/ppc-opcode.h> 30b8b572e1SStephen Rothwell 31919fc6e3SPaul E. McKenney #define smp_mb__after_unlock_lock() smp_mb() /* Full ordering for lock. */ 32919fc6e3SPaul E. McKenney 33b8b572e1SStephen Rothwell #ifdef CONFIG_PPC64 34b8b572e1SStephen Rothwell /* use 0x800000yy when locked, where yy == CPU number */ 3554bb7f4bSAnton Blanchard #ifdef __BIG_ENDIAN__ 36b8b572e1SStephen Rothwell #define LOCK_TOKEN (*(u32 *)(&get_paca()->lock_token)) 37b8b572e1SStephen Rothwell #else 3854bb7f4bSAnton Blanchard #define LOCK_TOKEN (*(u32 *)(&get_paca()->paca_index)) 3954bb7f4bSAnton Blanchard #endif 4054bb7f4bSAnton Blanchard #else 41b8b572e1SStephen Rothwell #define LOCK_TOKEN 1 42b8b572e1SStephen Rothwell #endif 43b8b572e1SStephen Rothwell 44b8b572e1SStephen Rothwell #if defined(CONFIG_PPC64) && defined(CONFIG_SMP) 45b8b572e1SStephen Rothwell #define CLEAR_IO_SYNC (get_paca()->io_sync = 0) 46b8b572e1SStephen Rothwell #define SYNC_IO do { \ 47b8b572e1SStephen Rothwell if (unlikely(get_paca()->io_sync)) { \ 48b8b572e1SStephen Rothwell mb(); \ 49b8b572e1SStephen Rothwell get_paca()->io_sync = 0; \ 50b8b572e1SStephen Rothwell } \ 51b8b572e1SStephen Rothwell } while (0) 52b8b572e1SStephen Rothwell #else 53b8b572e1SStephen Rothwell #define CLEAR_IO_SYNC 54b8b572e1SStephen Rothwell #define SYNC_IO 55b8b572e1SStephen Rothwell #endif 56b8b572e1SStephen Rothwell 573405d230SMichael Ellerman static __always_inline int arch_spin_value_unlocked(arch_spinlock_t lock) 583405d230SMichael Ellerman { 593405d230SMichael Ellerman return lock.slock == 0; 603405d230SMichael Ellerman } 613405d230SMichael Ellerman 627179ba52SMichael Ellerman static inline int arch_spin_is_locked(arch_spinlock_t *lock) 637179ba52SMichael Ellerman { 6451d7d520SMichael Ellerman smp_mb(); 657179ba52SMichael Ellerman return !arch_spin_value_unlocked(*lock); 667179ba52SMichael Ellerman } 677179ba52SMichael Ellerman 68b8b572e1SStephen Rothwell /* 69b8b572e1SStephen Rothwell * This returns the old value in the lock, so we succeeded 70b8b572e1SStephen Rothwell * in getting the lock if the return value is 0. 71b8b572e1SStephen Rothwell */ 720199c4e6SThomas Gleixner static inline unsigned long __arch_spin_trylock(arch_spinlock_t *lock) 73b8b572e1SStephen Rothwell { 74b8b572e1SStephen Rothwell unsigned long tmp, token; 75b8b572e1SStephen Rothwell 76b8b572e1SStephen Rothwell token = LOCK_TOKEN; 77b8b572e1SStephen Rothwell __asm__ __volatile__( 784e14a4d1SAnton Blanchard "1: " PPC_LWARX(%0,0,%2,1) "\n\ 79b8b572e1SStephen Rothwell cmpwi 0,%0,0\n\ 80b8b572e1SStephen Rothwell bne- 2f\n\ 81b8b572e1SStephen Rothwell stwcx. %1,0,%2\n\ 82f10e2e5bSAnton Blanchard bne- 1b\n" 83f10e2e5bSAnton Blanchard PPC_ACQUIRE_BARRIER 84f10e2e5bSAnton Blanchard "2:" 85f10e2e5bSAnton Blanchard : "=&r" (tmp) 86b8b572e1SStephen Rothwell : "r" (token), "r" (&lock->slock) 87b8b572e1SStephen Rothwell : "cr0", "memory"); 88b8b572e1SStephen Rothwell 89b8b572e1SStephen Rothwell return tmp; 90b8b572e1SStephen Rothwell } 91b8b572e1SStephen Rothwell 920199c4e6SThomas Gleixner static inline int arch_spin_trylock(arch_spinlock_t *lock) 93b8b572e1SStephen Rothwell { 94b8b572e1SStephen Rothwell CLEAR_IO_SYNC; 950199c4e6SThomas Gleixner return __arch_spin_trylock(lock) == 0; 96b8b572e1SStephen Rothwell } 97b8b572e1SStephen Rothwell 98b8b572e1SStephen Rothwell /* 99b8b572e1SStephen Rothwell * On a system with shared processors (that is, where a physical 100b8b572e1SStephen Rothwell * processor is multiplexed between several virtual processors), 101b8b572e1SStephen Rothwell * there is no point spinning on a lock if the holder of the lock 102b8b572e1SStephen Rothwell * isn't currently scheduled on a physical processor. Instead 103b8b572e1SStephen Rothwell * we detect this situation and ask the hypervisor to give the 104b8b572e1SStephen Rothwell * rest of our timeslice to the lock holder. 105b8b572e1SStephen Rothwell * 106b8b572e1SStephen Rothwell * So that we can tell which virtual processor is holding a lock, 107b8b572e1SStephen Rothwell * we put 0x80000000 | smp_processor_id() in the lock when it is 108b8b572e1SStephen Rothwell * held. Conveniently, we have a word in the paca that holds this 109b8b572e1SStephen Rothwell * value. 110b8b572e1SStephen Rothwell */ 111b8b572e1SStephen Rothwell 1121b041885SStephen Rothwell #if defined(CONFIG_PPC_SPLPAR) 113b8b572e1SStephen Rothwell /* We only yield to the hypervisor if we are in shared processor mode */ 114f13c13a0SAnton Blanchard #define SHARED_PROCESSOR (lppaca_shared_proc(local_paca->lppaca_ptr)) 115445c8951SThomas Gleixner extern void __spin_yield(arch_spinlock_t *lock); 116fb3a6bbcSThomas Gleixner extern void __rw_yield(arch_rwlock_t *lock); 1171b041885SStephen Rothwell #else /* SPLPAR */ 118b8b572e1SStephen Rothwell #define __spin_yield(x) barrier() 119b8b572e1SStephen Rothwell #define __rw_yield(x) barrier() 120b8b572e1SStephen Rothwell #define SHARED_PROCESSOR 0 121b8b572e1SStephen Rothwell #endif 122b8b572e1SStephen Rothwell 1230199c4e6SThomas Gleixner static inline void arch_spin_lock(arch_spinlock_t *lock) 124b8b572e1SStephen Rothwell { 125b8b572e1SStephen Rothwell CLEAR_IO_SYNC; 126b8b572e1SStephen Rothwell while (1) { 1270199c4e6SThomas Gleixner if (likely(__arch_spin_trylock(lock) == 0)) 128b8b572e1SStephen Rothwell break; 129b8b572e1SStephen Rothwell do { 130b8b572e1SStephen Rothwell HMT_low(); 131b8b572e1SStephen Rothwell if (SHARED_PROCESSOR) 132b8b572e1SStephen Rothwell __spin_yield(lock); 133b8b572e1SStephen Rothwell } while (unlikely(lock->slock != 0)); 134b8b572e1SStephen Rothwell HMT_medium(); 135b8b572e1SStephen Rothwell } 136b8b572e1SStephen Rothwell } 137b8b572e1SStephen Rothwell 138b8b572e1SStephen Rothwell static inline 1390199c4e6SThomas Gleixner void arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags) 140b8b572e1SStephen Rothwell { 141b8b572e1SStephen Rothwell unsigned long flags_dis; 142b8b572e1SStephen Rothwell 143b8b572e1SStephen Rothwell CLEAR_IO_SYNC; 144b8b572e1SStephen Rothwell while (1) { 1450199c4e6SThomas Gleixner if (likely(__arch_spin_trylock(lock) == 0)) 146b8b572e1SStephen Rothwell break; 147b8b572e1SStephen Rothwell local_save_flags(flags_dis); 148b8b572e1SStephen Rothwell local_irq_restore(flags); 149b8b572e1SStephen Rothwell do { 150b8b572e1SStephen Rothwell HMT_low(); 151b8b572e1SStephen Rothwell if (SHARED_PROCESSOR) 152b8b572e1SStephen Rothwell __spin_yield(lock); 153b8b572e1SStephen Rothwell } while (unlikely(lock->slock != 0)); 154b8b572e1SStephen Rothwell HMT_medium(); 155b8b572e1SStephen Rothwell local_irq_restore(flags_dis); 156b8b572e1SStephen Rothwell } 157b8b572e1SStephen Rothwell } 158b8b572e1SStephen Rothwell 1590199c4e6SThomas Gleixner static inline void arch_spin_unlock(arch_spinlock_t *lock) 160b8b572e1SStephen Rothwell { 161b8b572e1SStephen Rothwell SYNC_IO; 1620199c4e6SThomas Gleixner __asm__ __volatile__("# arch_spin_unlock\n\t" 163f10e2e5bSAnton Blanchard PPC_RELEASE_BARRIER: : :"memory"); 164b8b572e1SStephen Rothwell lock->slock = 0; 165b8b572e1SStephen Rothwell } 166b8b572e1SStephen Rothwell 167b8b572e1SStephen Rothwell #ifdef CONFIG_PPC64 1680199c4e6SThomas Gleixner extern void arch_spin_unlock_wait(arch_spinlock_t *lock); 169b8b572e1SStephen Rothwell #else 1700199c4e6SThomas Gleixner #define arch_spin_unlock_wait(lock) \ 1710199c4e6SThomas Gleixner do { while (arch_spin_is_locked(lock)) cpu_relax(); } while (0) 172b8b572e1SStephen Rothwell #endif 173b8b572e1SStephen Rothwell 174b8b572e1SStephen Rothwell /* 175b8b572e1SStephen Rothwell * Read-write spinlocks, allowing multiple readers 176b8b572e1SStephen Rothwell * but only one writer. 177b8b572e1SStephen Rothwell * 178b8b572e1SStephen Rothwell * NOTE! it is quite common to have readers in interrupts 179b8b572e1SStephen Rothwell * but no interrupt writers. For those circumstances we 180b8b572e1SStephen Rothwell * can "mix" irq-safe locks - any writer needs to get a 181b8b572e1SStephen Rothwell * irq-safe write-lock, but readers can get non-irqsafe 182b8b572e1SStephen Rothwell * read-locks. 183b8b572e1SStephen Rothwell */ 184b8b572e1SStephen Rothwell 185e5931943SThomas Gleixner #define arch_read_can_lock(rw) ((rw)->lock >= 0) 186e5931943SThomas Gleixner #define arch_write_can_lock(rw) (!(rw)->lock) 187b8b572e1SStephen Rothwell 188b8b572e1SStephen Rothwell #ifdef CONFIG_PPC64 189b8b572e1SStephen Rothwell #define __DO_SIGN_EXTEND "extsw %0,%0\n" 190b8b572e1SStephen Rothwell #define WRLOCK_TOKEN LOCK_TOKEN /* it's negative */ 191b8b572e1SStephen Rothwell #else 192b8b572e1SStephen Rothwell #define __DO_SIGN_EXTEND 193b8b572e1SStephen Rothwell #define WRLOCK_TOKEN (-1) 194b8b572e1SStephen Rothwell #endif 195b8b572e1SStephen Rothwell 196b8b572e1SStephen Rothwell /* 197b8b572e1SStephen Rothwell * This returns the old value in the lock + 1, 198b8b572e1SStephen Rothwell * so we got a read lock if the return value is > 0. 199b8b572e1SStephen Rothwell */ 200e5931943SThomas Gleixner static inline long __arch_read_trylock(arch_rwlock_t *rw) 201b8b572e1SStephen Rothwell { 202b8b572e1SStephen Rothwell long tmp; 203b8b572e1SStephen Rothwell 204b8b572e1SStephen Rothwell __asm__ __volatile__( 2054e14a4d1SAnton Blanchard "1: " PPC_LWARX(%0,0,%1,1) "\n" 206b8b572e1SStephen Rothwell __DO_SIGN_EXTEND 207b8b572e1SStephen Rothwell " addic. %0,%0,1\n\ 208b8b572e1SStephen Rothwell ble- 2f\n" 209b8b572e1SStephen Rothwell PPC405_ERR77(0,%1) 210b8b572e1SStephen Rothwell " stwcx. %0,0,%1\n\ 211f10e2e5bSAnton Blanchard bne- 1b\n" 212f10e2e5bSAnton Blanchard PPC_ACQUIRE_BARRIER 213f10e2e5bSAnton Blanchard "2:" : "=&r" (tmp) 214b8b572e1SStephen Rothwell : "r" (&rw->lock) 215b8b572e1SStephen Rothwell : "cr0", "xer", "memory"); 216b8b572e1SStephen Rothwell 217b8b572e1SStephen Rothwell return tmp; 218b8b572e1SStephen Rothwell } 219b8b572e1SStephen Rothwell 220b8b572e1SStephen Rothwell /* 221b8b572e1SStephen Rothwell * This returns the old value in the lock, 222b8b572e1SStephen Rothwell * so we got the write lock if the return value is 0. 223b8b572e1SStephen Rothwell */ 224e5931943SThomas Gleixner static inline long __arch_write_trylock(arch_rwlock_t *rw) 225b8b572e1SStephen Rothwell { 226b8b572e1SStephen Rothwell long tmp, token; 227b8b572e1SStephen Rothwell 228b8b572e1SStephen Rothwell token = WRLOCK_TOKEN; 229b8b572e1SStephen Rothwell __asm__ __volatile__( 2304e14a4d1SAnton Blanchard "1: " PPC_LWARX(%0,0,%2,1) "\n\ 231b8b572e1SStephen Rothwell cmpwi 0,%0,0\n\ 232b8b572e1SStephen Rothwell bne- 2f\n" 233b8b572e1SStephen Rothwell PPC405_ERR77(0,%1) 234b8b572e1SStephen Rothwell " stwcx. %1,0,%2\n\ 235f10e2e5bSAnton Blanchard bne- 1b\n" 236f10e2e5bSAnton Blanchard PPC_ACQUIRE_BARRIER 237f10e2e5bSAnton Blanchard "2:" : "=&r" (tmp) 238b8b572e1SStephen Rothwell : "r" (token), "r" (&rw->lock) 239b8b572e1SStephen Rothwell : "cr0", "memory"); 240b8b572e1SStephen Rothwell 241b8b572e1SStephen Rothwell return tmp; 242b8b572e1SStephen Rothwell } 243b8b572e1SStephen Rothwell 244e5931943SThomas Gleixner static inline void arch_read_lock(arch_rwlock_t *rw) 245b8b572e1SStephen Rothwell { 246b8b572e1SStephen Rothwell while (1) { 247e5931943SThomas Gleixner if (likely(__arch_read_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 void arch_write_lock(arch_rwlock_t *rw) 259b8b572e1SStephen Rothwell { 260b8b572e1SStephen Rothwell while (1) { 261e5931943SThomas Gleixner if (likely(__arch_write_trylock(rw) == 0)) 262b8b572e1SStephen Rothwell break; 263b8b572e1SStephen Rothwell do { 264b8b572e1SStephen Rothwell HMT_low(); 265b8b572e1SStephen Rothwell if (SHARED_PROCESSOR) 266b8b572e1SStephen Rothwell __rw_yield(rw); 267b8b572e1SStephen Rothwell } while (unlikely(rw->lock != 0)); 268b8b572e1SStephen Rothwell HMT_medium(); 269b8b572e1SStephen Rothwell } 270b8b572e1SStephen Rothwell } 271b8b572e1SStephen Rothwell 272e5931943SThomas Gleixner static inline int arch_read_trylock(arch_rwlock_t *rw) 273b8b572e1SStephen Rothwell { 274e5931943SThomas Gleixner return __arch_read_trylock(rw) > 0; 275b8b572e1SStephen Rothwell } 276b8b572e1SStephen Rothwell 277e5931943SThomas Gleixner static inline int arch_write_trylock(arch_rwlock_t *rw) 278b8b572e1SStephen Rothwell { 279e5931943SThomas Gleixner return __arch_write_trylock(rw) == 0; 280b8b572e1SStephen Rothwell } 281b8b572e1SStephen Rothwell 282e5931943SThomas Gleixner static inline void arch_read_unlock(arch_rwlock_t *rw) 283b8b572e1SStephen Rothwell { 284b8b572e1SStephen Rothwell long tmp; 285b8b572e1SStephen Rothwell 286b8b572e1SStephen Rothwell __asm__ __volatile__( 287b8b572e1SStephen Rothwell "# read_unlock\n\t" 288f10e2e5bSAnton Blanchard PPC_RELEASE_BARRIER 289b8b572e1SStephen Rothwell "1: lwarx %0,0,%1\n\ 290b8b572e1SStephen Rothwell addic %0,%0,-1\n" 291b8b572e1SStephen Rothwell PPC405_ERR77(0,%1) 292b8b572e1SStephen Rothwell " stwcx. %0,0,%1\n\ 293b8b572e1SStephen Rothwell bne- 1b" 294b8b572e1SStephen Rothwell : "=&r"(tmp) 295b8b572e1SStephen Rothwell : "r"(&rw->lock) 296efc3624cSPaul Mackerras : "cr0", "xer", "memory"); 297b8b572e1SStephen Rothwell } 298b8b572e1SStephen Rothwell 299e5931943SThomas Gleixner static inline void arch_write_unlock(arch_rwlock_t *rw) 300b8b572e1SStephen Rothwell { 301b8b572e1SStephen Rothwell __asm__ __volatile__("# write_unlock\n\t" 302f10e2e5bSAnton Blanchard PPC_RELEASE_BARRIER: : :"memory"); 303b8b572e1SStephen Rothwell rw->lock = 0; 304b8b572e1SStephen Rothwell } 305b8b572e1SStephen Rothwell 306e5931943SThomas Gleixner #define arch_read_lock_flags(lock, flags) arch_read_lock(lock) 307e5931943SThomas Gleixner #define arch_write_lock_flags(lock, flags) arch_write_lock(lock) 308f5f7eac4SRobin Holt 3090199c4e6SThomas Gleixner #define arch_spin_relax(lock) __spin_yield(lock) 3100199c4e6SThomas Gleixner #define arch_read_relax(lock) __rw_yield(lock) 3110199c4e6SThomas Gleixner #define arch_write_relax(lock) __rw_yield(lock) 312b8b572e1SStephen Rothwell 313b8b572e1SStephen Rothwell #endif /* __KERNEL__ */ 314b8b572e1SStephen Rothwell #endif /* __ASM_SPINLOCK_H */ 315