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 31b8b572e1SStephen Rothwell #ifdef CONFIG_PPC64 32b8b572e1SStephen Rothwell /* use 0x800000yy when locked, where yy == CPU number */ 3354bb7f4bSAnton Blanchard #ifdef __BIG_ENDIAN__ 34b8b572e1SStephen Rothwell #define LOCK_TOKEN (*(u32 *)(&get_paca()->lock_token)) 35b8b572e1SStephen Rothwell #else 3654bb7f4bSAnton Blanchard #define LOCK_TOKEN (*(u32 *)(&get_paca()->paca_index)) 3754bb7f4bSAnton Blanchard #endif 3854bb7f4bSAnton Blanchard #else 39b8b572e1SStephen Rothwell #define LOCK_TOKEN 1 40b8b572e1SStephen Rothwell #endif 41b8b572e1SStephen Rothwell 42b8b572e1SStephen Rothwell #if defined(CONFIG_PPC64) && defined(CONFIG_SMP) 43b8b572e1SStephen Rothwell #define CLEAR_IO_SYNC (get_paca()->io_sync = 0) 44b8b572e1SStephen Rothwell #define SYNC_IO do { \ 45b8b572e1SStephen Rothwell if (unlikely(get_paca()->io_sync)) { \ 46b8b572e1SStephen Rothwell mb(); \ 47b8b572e1SStephen Rothwell get_paca()->io_sync = 0; \ 48b8b572e1SStephen Rothwell } \ 49b8b572e1SStephen Rothwell } while (0) 50b8b572e1SStephen Rothwell #else 51b8b572e1SStephen Rothwell #define CLEAR_IO_SYNC 52b8b572e1SStephen Rothwell #define SYNC_IO 53b8b572e1SStephen Rothwell #endif 54b8b572e1SStephen Rothwell 553405d230SMichael Ellerman static __always_inline int arch_spin_value_unlocked(arch_spinlock_t lock) 563405d230SMichael Ellerman { 573405d230SMichael Ellerman return lock.slock == 0; 583405d230SMichael Ellerman } 593405d230SMichael Ellerman 607179ba52SMichael Ellerman static inline int arch_spin_is_locked(arch_spinlock_t *lock) 617179ba52SMichael Ellerman { 627179ba52SMichael Ellerman return !arch_spin_value_unlocked(*lock); 637179ba52SMichael Ellerman } 647179ba52SMichael Ellerman 65b8b572e1SStephen Rothwell /* 66b8b572e1SStephen Rothwell * This returns the old value in the lock, so we succeeded 67b8b572e1SStephen Rothwell * in getting the lock if the return value is 0. 68b8b572e1SStephen Rothwell */ 690199c4e6SThomas Gleixner static inline unsigned long __arch_spin_trylock(arch_spinlock_t *lock) 70b8b572e1SStephen Rothwell { 71b8b572e1SStephen Rothwell unsigned long tmp, token; 72b8b572e1SStephen Rothwell 73b8b572e1SStephen Rothwell token = LOCK_TOKEN; 74b8b572e1SStephen Rothwell __asm__ __volatile__( 754e14a4d1SAnton Blanchard "1: " PPC_LWARX(%0,0,%2,1) "\n\ 76b8b572e1SStephen Rothwell cmpwi 0,%0,0\n\ 77b8b572e1SStephen Rothwell bne- 2f\n\ 78b8b572e1SStephen Rothwell stwcx. %1,0,%2\n\ 79f10e2e5bSAnton Blanchard bne- 1b\n" 80f10e2e5bSAnton Blanchard PPC_ACQUIRE_BARRIER 81f10e2e5bSAnton Blanchard "2:" 82f10e2e5bSAnton Blanchard : "=&r" (tmp) 83b8b572e1SStephen Rothwell : "r" (token), "r" (&lock->slock) 84b8b572e1SStephen Rothwell : "cr0", "memory"); 85b8b572e1SStephen Rothwell 86b8b572e1SStephen Rothwell return tmp; 87b8b572e1SStephen Rothwell } 88b8b572e1SStephen Rothwell 890199c4e6SThomas Gleixner static inline int arch_spin_trylock(arch_spinlock_t *lock) 90b8b572e1SStephen Rothwell { 91b8b572e1SStephen Rothwell CLEAR_IO_SYNC; 920199c4e6SThomas Gleixner return __arch_spin_trylock(lock) == 0; 93b8b572e1SStephen Rothwell } 94b8b572e1SStephen Rothwell 95b8b572e1SStephen Rothwell /* 96b8b572e1SStephen Rothwell * On a system with shared processors (that is, where a physical 97b8b572e1SStephen Rothwell * processor is multiplexed between several virtual processors), 98b8b572e1SStephen Rothwell * there is no point spinning on a lock if the holder of the lock 99b8b572e1SStephen Rothwell * isn't currently scheduled on a physical processor. Instead 100b8b572e1SStephen Rothwell * we detect this situation and ask the hypervisor to give the 101b8b572e1SStephen Rothwell * rest of our timeslice to the lock holder. 102b8b572e1SStephen Rothwell * 103b8b572e1SStephen Rothwell * So that we can tell which virtual processor is holding a lock, 104b8b572e1SStephen Rothwell * we put 0x80000000 | smp_processor_id() in the lock when it is 105b8b572e1SStephen Rothwell * held. Conveniently, we have a word in the paca that holds this 106b8b572e1SStephen Rothwell * value. 107b8b572e1SStephen Rothwell */ 108b8b572e1SStephen Rothwell 1091b041885SStephen Rothwell #if defined(CONFIG_PPC_SPLPAR) 110b8b572e1SStephen Rothwell /* We only yield to the hypervisor if we are in shared processor mode */ 111f13c13a0SAnton Blanchard #define SHARED_PROCESSOR (lppaca_shared_proc(local_paca->lppaca_ptr)) 112445c8951SThomas Gleixner extern void __spin_yield(arch_spinlock_t *lock); 113fb3a6bbcSThomas Gleixner extern void __rw_yield(arch_rwlock_t *lock); 1141b041885SStephen Rothwell #else /* SPLPAR */ 115b8b572e1SStephen Rothwell #define __spin_yield(x) barrier() 116b8b572e1SStephen Rothwell #define __rw_yield(x) barrier() 117b8b572e1SStephen Rothwell #define SHARED_PROCESSOR 0 118b8b572e1SStephen Rothwell #endif 119b8b572e1SStephen Rothwell 1200199c4e6SThomas Gleixner static inline void arch_spin_lock(arch_spinlock_t *lock) 121b8b572e1SStephen Rothwell { 122b8b572e1SStephen Rothwell CLEAR_IO_SYNC; 123b8b572e1SStephen Rothwell while (1) { 1240199c4e6SThomas Gleixner if (likely(__arch_spin_trylock(lock) == 0)) 125b8b572e1SStephen Rothwell break; 126b8b572e1SStephen Rothwell do { 127b8b572e1SStephen Rothwell HMT_low(); 128b8b572e1SStephen Rothwell if (SHARED_PROCESSOR) 129b8b572e1SStephen Rothwell __spin_yield(lock); 130b8b572e1SStephen Rothwell } while (unlikely(lock->slock != 0)); 131b8b572e1SStephen Rothwell HMT_medium(); 132b8b572e1SStephen Rothwell } 133b8b572e1SStephen Rothwell } 134b8b572e1SStephen Rothwell 135b8b572e1SStephen Rothwell static inline 1360199c4e6SThomas Gleixner void arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags) 137b8b572e1SStephen Rothwell { 138b8b572e1SStephen Rothwell unsigned long flags_dis; 139b8b572e1SStephen Rothwell 140b8b572e1SStephen Rothwell CLEAR_IO_SYNC; 141b8b572e1SStephen Rothwell while (1) { 1420199c4e6SThomas Gleixner if (likely(__arch_spin_trylock(lock) == 0)) 143b8b572e1SStephen Rothwell break; 144b8b572e1SStephen Rothwell local_save_flags(flags_dis); 145b8b572e1SStephen Rothwell local_irq_restore(flags); 146b8b572e1SStephen Rothwell do { 147b8b572e1SStephen Rothwell HMT_low(); 148b8b572e1SStephen Rothwell if (SHARED_PROCESSOR) 149b8b572e1SStephen Rothwell __spin_yield(lock); 150b8b572e1SStephen Rothwell } while (unlikely(lock->slock != 0)); 151b8b572e1SStephen Rothwell HMT_medium(); 152b8b572e1SStephen Rothwell local_irq_restore(flags_dis); 153b8b572e1SStephen Rothwell } 154b8b572e1SStephen Rothwell } 155b8b572e1SStephen Rothwell 1560199c4e6SThomas Gleixner static inline void arch_spin_unlock(arch_spinlock_t *lock) 157b8b572e1SStephen Rothwell { 158b8b572e1SStephen Rothwell SYNC_IO; 1590199c4e6SThomas Gleixner __asm__ __volatile__("# arch_spin_unlock\n\t" 160f10e2e5bSAnton Blanchard PPC_RELEASE_BARRIER: : :"memory"); 161b8b572e1SStephen Rothwell lock->slock = 0; 162b8b572e1SStephen Rothwell } 163b8b572e1SStephen Rothwell 164b8b572e1SStephen Rothwell #ifdef CONFIG_PPC64 1650199c4e6SThomas Gleixner extern void arch_spin_unlock_wait(arch_spinlock_t *lock); 166b8b572e1SStephen Rothwell #else 1670199c4e6SThomas Gleixner #define arch_spin_unlock_wait(lock) \ 1680199c4e6SThomas Gleixner do { while (arch_spin_is_locked(lock)) cpu_relax(); } while (0) 169b8b572e1SStephen Rothwell #endif 170b8b572e1SStephen Rothwell 171b8b572e1SStephen Rothwell /* 172b8b572e1SStephen Rothwell * Read-write spinlocks, allowing multiple readers 173b8b572e1SStephen Rothwell * but only one writer. 174b8b572e1SStephen Rothwell * 175b8b572e1SStephen Rothwell * NOTE! it is quite common to have readers in interrupts 176b8b572e1SStephen Rothwell * but no interrupt writers. For those circumstances we 177b8b572e1SStephen Rothwell * can "mix" irq-safe locks - any writer needs to get a 178b8b572e1SStephen Rothwell * irq-safe write-lock, but readers can get non-irqsafe 179b8b572e1SStephen Rothwell * read-locks. 180b8b572e1SStephen Rothwell */ 181b8b572e1SStephen Rothwell 182e5931943SThomas Gleixner #define arch_read_can_lock(rw) ((rw)->lock >= 0) 183e5931943SThomas Gleixner #define arch_write_can_lock(rw) (!(rw)->lock) 184b8b572e1SStephen Rothwell 185b8b572e1SStephen Rothwell #ifdef CONFIG_PPC64 186b8b572e1SStephen Rothwell #define __DO_SIGN_EXTEND "extsw %0,%0\n" 187b8b572e1SStephen Rothwell #define WRLOCK_TOKEN LOCK_TOKEN /* it's negative */ 188b8b572e1SStephen Rothwell #else 189b8b572e1SStephen Rothwell #define __DO_SIGN_EXTEND 190b8b572e1SStephen Rothwell #define WRLOCK_TOKEN (-1) 191b8b572e1SStephen Rothwell #endif 192b8b572e1SStephen Rothwell 193b8b572e1SStephen Rothwell /* 194b8b572e1SStephen Rothwell * This returns the old value in the lock + 1, 195b8b572e1SStephen Rothwell * so we got a read lock if the return value is > 0. 196b8b572e1SStephen Rothwell */ 197e5931943SThomas Gleixner static inline long __arch_read_trylock(arch_rwlock_t *rw) 198b8b572e1SStephen Rothwell { 199b8b572e1SStephen Rothwell long tmp; 200b8b572e1SStephen Rothwell 201b8b572e1SStephen Rothwell __asm__ __volatile__( 2024e14a4d1SAnton Blanchard "1: " PPC_LWARX(%0,0,%1,1) "\n" 203b8b572e1SStephen Rothwell __DO_SIGN_EXTEND 204b8b572e1SStephen Rothwell " addic. %0,%0,1\n\ 205b8b572e1SStephen Rothwell ble- 2f\n" 206b8b572e1SStephen Rothwell PPC405_ERR77(0,%1) 207b8b572e1SStephen Rothwell " stwcx. %0,0,%1\n\ 208f10e2e5bSAnton Blanchard bne- 1b\n" 209f10e2e5bSAnton Blanchard PPC_ACQUIRE_BARRIER 210f10e2e5bSAnton Blanchard "2:" : "=&r" (tmp) 211b8b572e1SStephen Rothwell : "r" (&rw->lock) 212b8b572e1SStephen Rothwell : "cr0", "xer", "memory"); 213b8b572e1SStephen Rothwell 214b8b572e1SStephen Rothwell return tmp; 215b8b572e1SStephen Rothwell } 216b8b572e1SStephen Rothwell 217b8b572e1SStephen Rothwell /* 218b8b572e1SStephen Rothwell * This returns the old value in the lock, 219b8b572e1SStephen Rothwell * so we got the write lock if the return value is 0. 220b8b572e1SStephen Rothwell */ 221e5931943SThomas Gleixner static inline long __arch_write_trylock(arch_rwlock_t *rw) 222b8b572e1SStephen Rothwell { 223b8b572e1SStephen Rothwell long tmp, token; 224b8b572e1SStephen Rothwell 225b8b572e1SStephen Rothwell token = WRLOCK_TOKEN; 226b8b572e1SStephen Rothwell __asm__ __volatile__( 2274e14a4d1SAnton Blanchard "1: " PPC_LWARX(%0,0,%2,1) "\n\ 228b8b572e1SStephen Rothwell cmpwi 0,%0,0\n\ 229b8b572e1SStephen Rothwell bne- 2f\n" 230b8b572e1SStephen Rothwell PPC405_ERR77(0,%1) 231b8b572e1SStephen Rothwell " stwcx. %1,0,%2\n\ 232f10e2e5bSAnton Blanchard bne- 1b\n" 233f10e2e5bSAnton Blanchard PPC_ACQUIRE_BARRIER 234f10e2e5bSAnton Blanchard "2:" : "=&r" (tmp) 235b8b572e1SStephen Rothwell : "r" (token), "r" (&rw->lock) 236b8b572e1SStephen Rothwell : "cr0", "memory"); 237b8b572e1SStephen Rothwell 238b8b572e1SStephen Rothwell return tmp; 239b8b572e1SStephen Rothwell } 240b8b572e1SStephen Rothwell 241e5931943SThomas Gleixner static inline void arch_read_lock(arch_rwlock_t *rw) 242b8b572e1SStephen Rothwell { 243b8b572e1SStephen Rothwell while (1) { 244e5931943SThomas Gleixner if (likely(__arch_read_trylock(rw) > 0)) 245b8b572e1SStephen Rothwell break; 246b8b572e1SStephen Rothwell do { 247b8b572e1SStephen Rothwell HMT_low(); 248b8b572e1SStephen Rothwell if (SHARED_PROCESSOR) 249b8b572e1SStephen Rothwell __rw_yield(rw); 250b8b572e1SStephen Rothwell } while (unlikely(rw->lock < 0)); 251b8b572e1SStephen Rothwell HMT_medium(); 252b8b572e1SStephen Rothwell } 253b8b572e1SStephen Rothwell } 254b8b572e1SStephen Rothwell 255e5931943SThomas Gleixner static inline void arch_write_lock(arch_rwlock_t *rw) 256b8b572e1SStephen Rothwell { 257b8b572e1SStephen Rothwell while (1) { 258e5931943SThomas Gleixner if (likely(__arch_write_trylock(rw) == 0)) 259b8b572e1SStephen Rothwell break; 260b8b572e1SStephen Rothwell do { 261b8b572e1SStephen Rothwell HMT_low(); 262b8b572e1SStephen Rothwell if (SHARED_PROCESSOR) 263b8b572e1SStephen Rothwell __rw_yield(rw); 264b8b572e1SStephen Rothwell } while (unlikely(rw->lock != 0)); 265b8b572e1SStephen Rothwell HMT_medium(); 266b8b572e1SStephen Rothwell } 267b8b572e1SStephen Rothwell } 268b8b572e1SStephen Rothwell 269e5931943SThomas Gleixner static inline int arch_read_trylock(arch_rwlock_t *rw) 270b8b572e1SStephen Rothwell { 271e5931943SThomas Gleixner return __arch_read_trylock(rw) > 0; 272b8b572e1SStephen Rothwell } 273b8b572e1SStephen Rothwell 274e5931943SThomas Gleixner static inline int arch_write_trylock(arch_rwlock_t *rw) 275b8b572e1SStephen Rothwell { 276e5931943SThomas Gleixner return __arch_write_trylock(rw) == 0; 277b8b572e1SStephen Rothwell } 278b8b572e1SStephen Rothwell 279e5931943SThomas Gleixner static inline void arch_read_unlock(arch_rwlock_t *rw) 280b8b572e1SStephen Rothwell { 281b8b572e1SStephen Rothwell long tmp; 282b8b572e1SStephen Rothwell 283b8b572e1SStephen Rothwell __asm__ __volatile__( 284b8b572e1SStephen Rothwell "# read_unlock\n\t" 285f10e2e5bSAnton Blanchard PPC_RELEASE_BARRIER 286b8b572e1SStephen Rothwell "1: lwarx %0,0,%1\n\ 287b8b572e1SStephen Rothwell addic %0,%0,-1\n" 288b8b572e1SStephen Rothwell PPC405_ERR77(0,%1) 289b8b572e1SStephen Rothwell " stwcx. %0,0,%1\n\ 290b8b572e1SStephen Rothwell bne- 1b" 291b8b572e1SStephen Rothwell : "=&r"(tmp) 292b8b572e1SStephen Rothwell : "r"(&rw->lock) 293efc3624cSPaul Mackerras : "cr0", "xer", "memory"); 294b8b572e1SStephen Rothwell } 295b8b572e1SStephen Rothwell 296e5931943SThomas Gleixner static inline void arch_write_unlock(arch_rwlock_t *rw) 297b8b572e1SStephen Rothwell { 298b8b572e1SStephen Rothwell __asm__ __volatile__("# write_unlock\n\t" 299f10e2e5bSAnton Blanchard PPC_RELEASE_BARRIER: : :"memory"); 300b8b572e1SStephen Rothwell rw->lock = 0; 301b8b572e1SStephen Rothwell } 302b8b572e1SStephen Rothwell 303e5931943SThomas Gleixner #define arch_read_lock_flags(lock, flags) arch_read_lock(lock) 304e5931943SThomas Gleixner #define arch_write_lock_flags(lock, flags) arch_write_lock(lock) 305f5f7eac4SRobin Holt 3060199c4e6SThomas Gleixner #define arch_spin_relax(lock) __spin_yield(lock) 3070199c4e6SThomas Gleixner #define arch_read_relax(lock) __rw_yield(lock) 3080199c4e6SThomas Gleixner #define arch_write_relax(lock) __rw_yield(lock) 309b8b572e1SStephen Rothwell 310b8b572e1SStephen Rothwell #endif /* __KERNEL__ */ 311b8b572e1SStephen Rothwell #endif /* __ASM_SPINLOCK_H */ 312