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 310199c4e6SThomas Gleixner #define arch_spin_is_locked(x) ((x)->slock != 0) 32b8b572e1SStephen Rothwell 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 62b8b572e1SStephen Rothwell /* 63b8b572e1SStephen Rothwell * This returns the old value in the lock, so we succeeded 64b8b572e1SStephen Rothwell * in getting the lock if the return value is 0. 65b8b572e1SStephen Rothwell */ 660199c4e6SThomas Gleixner static inline unsigned long __arch_spin_trylock(arch_spinlock_t *lock) 67b8b572e1SStephen Rothwell { 68b8b572e1SStephen Rothwell unsigned long tmp, token; 69b8b572e1SStephen Rothwell 70b8b572e1SStephen Rothwell token = LOCK_TOKEN; 71b8b572e1SStephen Rothwell __asm__ __volatile__( 724e14a4d1SAnton Blanchard "1: " PPC_LWARX(%0,0,%2,1) "\n\ 73b8b572e1SStephen Rothwell cmpwi 0,%0,0\n\ 74b8b572e1SStephen Rothwell bne- 2f\n\ 75b8b572e1SStephen Rothwell stwcx. %1,0,%2\n\ 76f10e2e5bSAnton Blanchard bne- 1b\n" 77f10e2e5bSAnton Blanchard PPC_ACQUIRE_BARRIER 78f10e2e5bSAnton Blanchard "2:" 79f10e2e5bSAnton Blanchard : "=&r" (tmp) 80b8b572e1SStephen Rothwell : "r" (token), "r" (&lock->slock) 81b8b572e1SStephen Rothwell : "cr0", "memory"); 82b8b572e1SStephen Rothwell 83b8b572e1SStephen Rothwell return tmp; 84b8b572e1SStephen Rothwell } 85b8b572e1SStephen Rothwell 860199c4e6SThomas Gleixner static inline int arch_spin_trylock(arch_spinlock_t *lock) 87b8b572e1SStephen Rothwell { 88b8b572e1SStephen Rothwell CLEAR_IO_SYNC; 890199c4e6SThomas Gleixner return __arch_spin_trylock(lock) == 0; 90b8b572e1SStephen Rothwell } 91b8b572e1SStephen Rothwell 92b8b572e1SStephen Rothwell /* 93b8b572e1SStephen Rothwell * On a system with shared processors (that is, where a physical 94b8b572e1SStephen Rothwell * processor is multiplexed between several virtual processors), 95b8b572e1SStephen Rothwell * there is no point spinning on a lock if the holder of the lock 96b8b572e1SStephen Rothwell * isn't currently scheduled on a physical processor. Instead 97b8b572e1SStephen Rothwell * we detect this situation and ask the hypervisor to give the 98b8b572e1SStephen Rothwell * rest of our timeslice to the lock holder. 99b8b572e1SStephen Rothwell * 100b8b572e1SStephen Rothwell * So that we can tell which virtual processor is holding a lock, 101b8b572e1SStephen Rothwell * we put 0x80000000 | smp_processor_id() in the lock when it is 102b8b572e1SStephen Rothwell * held. Conveniently, we have a word in the paca that holds this 103b8b572e1SStephen Rothwell * value. 104b8b572e1SStephen Rothwell */ 105b8b572e1SStephen Rothwell 1061b041885SStephen Rothwell #if defined(CONFIG_PPC_SPLPAR) 107b8b572e1SStephen Rothwell /* We only yield to the hypervisor if we are in shared processor mode */ 108f13c13a0SAnton Blanchard #define SHARED_PROCESSOR (lppaca_shared_proc(local_paca->lppaca_ptr)) 109445c8951SThomas Gleixner extern void __spin_yield(arch_spinlock_t *lock); 110fb3a6bbcSThomas Gleixner extern void __rw_yield(arch_rwlock_t *lock); 1111b041885SStephen Rothwell #else /* SPLPAR */ 112b8b572e1SStephen Rothwell #define __spin_yield(x) barrier() 113b8b572e1SStephen Rothwell #define __rw_yield(x) barrier() 114b8b572e1SStephen Rothwell #define SHARED_PROCESSOR 0 115b8b572e1SStephen Rothwell #endif 116b8b572e1SStephen Rothwell 1170199c4e6SThomas Gleixner static inline void arch_spin_lock(arch_spinlock_t *lock) 118b8b572e1SStephen Rothwell { 119b8b572e1SStephen Rothwell CLEAR_IO_SYNC; 120b8b572e1SStephen Rothwell while (1) { 1210199c4e6SThomas Gleixner if (likely(__arch_spin_trylock(lock) == 0)) 122b8b572e1SStephen Rothwell break; 123b8b572e1SStephen Rothwell do { 124b8b572e1SStephen Rothwell HMT_low(); 125b8b572e1SStephen Rothwell if (SHARED_PROCESSOR) 126b8b572e1SStephen Rothwell __spin_yield(lock); 127b8b572e1SStephen Rothwell } while (unlikely(lock->slock != 0)); 128b8b572e1SStephen Rothwell HMT_medium(); 129b8b572e1SStephen Rothwell } 130b8b572e1SStephen Rothwell } 131b8b572e1SStephen Rothwell 132b8b572e1SStephen Rothwell static inline 1330199c4e6SThomas Gleixner void arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags) 134b8b572e1SStephen Rothwell { 135b8b572e1SStephen Rothwell unsigned long flags_dis; 136b8b572e1SStephen Rothwell 137b8b572e1SStephen Rothwell CLEAR_IO_SYNC; 138b8b572e1SStephen Rothwell while (1) { 1390199c4e6SThomas Gleixner if (likely(__arch_spin_trylock(lock) == 0)) 140b8b572e1SStephen Rothwell break; 141b8b572e1SStephen Rothwell local_save_flags(flags_dis); 142b8b572e1SStephen Rothwell local_irq_restore(flags); 143b8b572e1SStephen Rothwell do { 144b8b572e1SStephen Rothwell HMT_low(); 145b8b572e1SStephen Rothwell if (SHARED_PROCESSOR) 146b8b572e1SStephen Rothwell __spin_yield(lock); 147b8b572e1SStephen Rothwell } while (unlikely(lock->slock != 0)); 148b8b572e1SStephen Rothwell HMT_medium(); 149b8b572e1SStephen Rothwell local_irq_restore(flags_dis); 150b8b572e1SStephen Rothwell } 151b8b572e1SStephen Rothwell } 152b8b572e1SStephen Rothwell 1530199c4e6SThomas Gleixner static inline void arch_spin_unlock(arch_spinlock_t *lock) 154b8b572e1SStephen Rothwell { 155b8b572e1SStephen Rothwell SYNC_IO; 1560199c4e6SThomas Gleixner __asm__ __volatile__("# arch_spin_unlock\n\t" 157f10e2e5bSAnton Blanchard PPC_RELEASE_BARRIER: : :"memory"); 158b8b572e1SStephen Rothwell lock->slock = 0; 159b8b572e1SStephen Rothwell } 160b8b572e1SStephen Rothwell 161b8b572e1SStephen Rothwell #ifdef CONFIG_PPC64 1620199c4e6SThomas Gleixner extern void arch_spin_unlock_wait(arch_spinlock_t *lock); 163b8b572e1SStephen Rothwell #else 1640199c4e6SThomas Gleixner #define arch_spin_unlock_wait(lock) \ 1650199c4e6SThomas Gleixner do { while (arch_spin_is_locked(lock)) cpu_relax(); } while (0) 166b8b572e1SStephen Rothwell #endif 167b8b572e1SStephen Rothwell 168b8b572e1SStephen Rothwell /* 169b8b572e1SStephen Rothwell * Read-write spinlocks, allowing multiple readers 170b8b572e1SStephen Rothwell * but only one writer. 171b8b572e1SStephen Rothwell * 172b8b572e1SStephen Rothwell * NOTE! it is quite common to have readers in interrupts 173b8b572e1SStephen Rothwell * but no interrupt writers. For those circumstances we 174b8b572e1SStephen Rothwell * can "mix" irq-safe locks - any writer needs to get a 175b8b572e1SStephen Rothwell * irq-safe write-lock, but readers can get non-irqsafe 176b8b572e1SStephen Rothwell * read-locks. 177b8b572e1SStephen Rothwell */ 178b8b572e1SStephen Rothwell 179e5931943SThomas Gleixner #define arch_read_can_lock(rw) ((rw)->lock >= 0) 180e5931943SThomas Gleixner #define arch_write_can_lock(rw) (!(rw)->lock) 181b8b572e1SStephen Rothwell 182b8b572e1SStephen Rothwell #ifdef CONFIG_PPC64 183b8b572e1SStephen Rothwell #define __DO_SIGN_EXTEND "extsw %0,%0\n" 184b8b572e1SStephen Rothwell #define WRLOCK_TOKEN LOCK_TOKEN /* it's negative */ 185b8b572e1SStephen Rothwell #else 186b8b572e1SStephen Rothwell #define __DO_SIGN_EXTEND 187b8b572e1SStephen Rothwell #define WRLOCK_TOKEN (-1) 188b8b572e1SStephen Rothwell #endif 189b8b572e1SStephen Rothwell 190b8b572e1SStephen Rothwell /* 191b8b572e1SStephen Rothwell * This returns the old value in the lock + 1, 192b8b572e1SStephen Rothwell * so we got a read lock if the return value is > 0. 193b8b572e1SStephen Rothwell */ 194e5931943SThomas Gleixner static inline long __arch_read_trylock(arch_rwlock_t *rw) 195b8b572e1SStephen Rothwell { 196b8b572e1SStephen Rothwell long tmp; 197b8b572e1SStephen Rothwell 198b8b572e1SStephen Rothwell __asm__ __volatile__( 1994e14a4d1SAnton Blanchard "1: " PPC_LWARX(%0,0,%1,1) "\n" 200b8b572e1SStephen Rothwell __DO_SIGN_EXTEND 201b8b572e1SStephen Rothwell " addic. %0,%0,1\n\ 202b8b572e1SStephen Rothwell ble- 2f\n" 203b8b572e1SStephen Rothwell PPC405_ERR77(0,%1) 204b8b572e1SStephen Rothwell " stwcx. %0,0,%1\n\ 205f10e2e5bSAnton Blanchard bne- 1b\n" 206f10e2e5bSAnton Blanchard PPC_ACQUIRE_BARRIER 207f10e2e5bSAnton Blanchard "2:" : "=&r" (tmp) 208b8b572e1SStephen Rothwell : "r" (&rw->lock) 209b8b572e1SStephen Rothwell : "cr0", "xer", "memory"); 210b8b572e1SStephen Rothwell 211b8b572e1SStephen Rothwell return tmp; 212b8b572e1SStephen Rothwell } 213b8b572e1SStephen Rothwell 214b8b572e1SStephen Rothwell /* 215b8b572e1SStephen Rothwell * This returns the old value in the lock, 216b8b572e1SStephen Rothwell * so we got the write lock if the return value is 0. 217b8b572e1SStephen Rothwell */ 218e5931943SThomas Gleixner static inline long __arch_write_trylock(arch_rwlock_t *rw) 219b8b572e1SStephen Rothwell { 220b8b572e1SStephen Rothwell long tmp, token; 221b8b572e1SStephen Rothwell 222b8b572e1SStephen Rothwell token = WRLOCK_TOKEN; 223b8b572e1SStephen Rothwell __asm__ __volatile__( 2244e14a4d1SAnton Blanchard "1: " PPC_LWARX(%0,0,%2,1) "\n\ 225b8b572e1SStephen Rothwell cmpwi 0,%0,0\n\ 226b8b572e1SStephen Rothwell bne- 2f\n" 227b8b572e1SStephen Rothwell PPC405_ERR77(0,%1) 228b8b572e1SStephen Rothwell " stwcx. %1,0,%2\n\ 229f10e2e5bSAnton Blanchard bne- 1b\n" 230f10e2e5bSAnton Blanchard PPC_ACQUIRE_BARRIER 231f10e2e5bSAnton Blanchard "2:" : "=&r" (tmp) 232b8b572e1SStephen Rothwell : "r" (token), "r" (&rw->lock) 233b8b572e1SStephen Rothwell : "cr0", "memory"); 234b8b572e1SStephen Rothwell 235b8b572e1SStephen Rothwell return tmp; 236b8b572e1SStephen Rothwell } 237b8b572e1SStephen Rothwell 238e5931943SThomas Gleixner static inline void arch_read_lock(arch_rwlock_t *rw) 239b8b572e1SStephen Rothwell { 240b8b572e1SStephen Rothwell while (1) { 241e5931943SThomas Gleixner if (likely(__arch_read_trylock(rw) > 0)) 242b8b572e1SStephen Rothwell break; 243b8b572e1SStephen Rothwell do { 244b8b572e1SStephen Rothwell HMT_low(); 245b8b572e1SStephen Rothwell if (SHARED_PROCESSOR) 246b8b572e1SStephen Rothwell __rw_yield(rw); 247b8b572e1SStephen Rothwell } while (unlikely(rw->lock < 0)); 248b8b572e1SStephen Rothwell HMT_medium(); 249b8b572e1SStephen Rothwell } 250b8b572e1SStephen Rothwell } 251b8b572e1SStephen Rothwell 252e5931943SThomas Gleixner static inline void arch_write_lock(arch_rwlock_t *rw) 253b8b572e1SStephen Rothwell { 254b8b572e1SStephen Rothwell while (1) { 255e5931943SThomas Gleixner if (likely(__arch_write_trylock(rw) == 0)) 256b8b572e1SStephen Rothwell break; 257b8b572e1SStephen Rothwell do { 258b8b572e1SStephen Rothwell HMT_low(); 259b8b572e1SStephen Rothwell if (SHARED_PROCESSOR) 260b8b572e1SStephen Rothwell __rw_yield(rw); 261b8b572e1SStephen Rothwell } while (unlikely(rw->lock != 0)); 262b8b572e1SStephen Rothwell HMT_medium(); 263b8b572e1SStephen Rothwell } 264b8b572e1SStephen Rothwell } 265b8b572e1SStephen Rothwell 266e5931943SThomas Gleixner static inline int arch_read_trylock(arch_rwlock_t *rw) 267b8b572e1SStephen Rothwell { 268e5931943SThomas Gleixner return __arch_read_trylock(rw) > 0; 269b8b572e1SStephen Rothwell } 270b8b572e1SStephen Rothwell 271e5931943SThomas Gleixner static inline int arch_write_trylock(arch_rwlock_t *rw) 272b8b572e1SStephen Rothwell { 273e5931943SThomas Gleixner return __arch_write_trylock(rw) == 0; 274b8b572e1SStephen Rothwell } 275b8b572e1SStephen Rothwell 276e5931943SThomas Gleixner static inline void arch_read_unlock(arch_rwlock_t *rw) 277b8b572e1SStephen Rothwell { 278b8b572e1SStephen Rothwell long tmp; 279b8b572e1SStephen Rothwell 280b8b572e1SStephen Rothwell __asm__ __volatile__( 281b8b572e1SStephen Rothwell "# read_unlock\n\t" 282f10e2e5bSAnton Blanchard PPC_RELEASE_BARRIER 283b8b572e1SStephen Rothwell "1: lwarx %0,0,%1\n\ 284b8b572e1SStephen Rothwell addic %0,%0,-1\n" 285b8b572e1SStephen Rothwell PPC405_ERR77(0,%1) 286b8b572e1SStephen Rothwell " stwcx. %0,0,%1\n\ 287b8b572e1SStephen Rothwell bne- 1b" 288b8b572e1SStephen Rothwell : "=&r"(tmp) 289b8b572e1SStephen Rothwell : "r"(&rw->lock) 290efc3624cSPaul Mackerras : "cr0", "xer", "memory"); 291b8b572e1SStephen Rothwell } 292b8b572e1SStephen Rothwell 293e5931943SThomas Gleixner static inline void arch_write_unlock(arch_rwlock_t *rw) 294b8b572e1SStephen Rothwell { 295b8b572e1SStephen Rothwell __asm__ __volatile__("# write_unlock\n\t" 296f10e2e5bSAnton Blanchard PPC_RELEASE_BARRIER: : :"memory"); 297b8b572e1SStephen Rothwell rw->lock = 0; 298b8b572e1SStephen Rothwell } 299b8b572e1SStephen Rothwell 300e5931943SThomas Gleixner #define arch_read_lock_flags(lock, flags) arch_read_lock(lock) 301e5931943SThomas Gleixner #define arch_write_lock_flags(lock, flags) arch_write_lock(lock) 302f5f7eac4SRobin Holt 3030199c4e6SThomas Gleixner #define arch_spin_relax(lock) __spin_yield(lock) 3040199c4e6SThomas Gleixner #define arch_read_relax(lock) __rw_yield(lock) 3050199c4e6SThomas Gleixner #define arch_write_relax(lock) __rw_yield(lock) 306b8b572e1SStephen Rothwell 307b8b572e1SStephen Rothwell #endif /* __KERNEL__ */ 308b8b572e1SStephen Rothwell #endif /* __ASM_SPINLOCK_H */ 309