+++ /dev/null
-#ifndef __ASM_SPINLOCK_H
-#define __ASM_SPINLOCK_H
-#ifdef __KERNEL__
-
-/*
- * Simple spin lock operations.
- *
- * Copyright (C) 2001-2004 Paul Mackerras <paulus@au.ibm.com>, IBM
- * Copyright (C) 2001 Anton Blanchard <anton@au.ibm.com>, IBM
- * Copyright (C) 2002 Dave Engebretsen <engebret@us.ibm.com>, IBM
- * Rework to support virtual processors
- *
- * Type of int is used as a full 64b word is not necessary.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
- *
- * (the type definitions are in asm/spinlock_types.h)
- */
-#include <linux/irqflags.h>
-#ifdef CONFIG_PPC64
-#include <asm/paca.h>
-#include <asm/hvcall.h>
-#include <asm/iseries/hv_call.h>
-#endif
-#include <asm/asm-compat.h>
-#include <asm/synch.h>
-
-#define __raw_spin_is_locked(x) ((x)->slock != 0)
-
-#ifdef CONFIG_PPC64
-/* use 0x800000yy when locked, where yy == CPU number */
-#define LOCK_TOKEN (*(u32 *)(&get_paca()->lock_token))
-#else
-#define LOCK_TOKEN 1
-#endif
-
-#if defined(CONFIG_PPC64) && defined(CONFIG_SMP)
-#define CLEAR_IO_SYNC (get_paca()->io_sync = 0)
-#define SYNC_IO do { \
- if (unlikely(get_paca()->io_sync)) { \
- mb(); \
- get_paca()->io_sync = 0; \
- } \
- } while (0)
-#else
-#define CLEAR_IO_SYNC
-#define SYNC_IO
-#endif
-
-/*
- * This returns the old value in the lock, so we succeeded
- * in getting the lock if the return value is 0.
- */
-static inline unsigned long __spin_trylock(raw_spinlock_t *lock)
-{
- unsigned long tmp, token;
-
- token = LOCK_TOKEN;
- __asm__ __volatile__(
-"1: lwarx %0,0,%2\n\
- cmpwi 0,%0,0\n\
- bne- 2f\n\
- stwcx. %1,0,%2\n\
- bne- 1b\n\
- isync\n\
-2:" : "=&r" (tmp)
- : "r" (token), "r" (&lock->slock)
- : "cr0", "memory");
-
- return tmp;
-}
-
-static inline int __raw_spin_trylock(raw_spinlock_t *lock)
-{
- CLEAR_IO_SYNC;
- return __spin_trylock(lock) == 0;
-}
-
-/*
- * On a system with shared processors (that is, where a physical
- * processor is multiplexed between several virtual processors),
- * there is no point spinning on a lock if the holder of the lock
- * isn't currently scheduled on a physical processor. Instead
- * we detect this situation and ask the hypervisor to give the
- * rest of our timeslice to the lock holder.
- *
- * So that we can tell which virtual processor is holding a lock,
- * we put 0x80000000 | smp_processor_id() in the lock when it is
- * held. Conveniently, we have a word in the paca that holds this
- * value.
- */
-
-#if defined(CONFIG_PPC_SPLPAR) || defined(CONFIG_PPC_ISERIES)
-/* We only yield to the hypervisor if we are in shared processor mode */
-#define SHARED_PROCESSOR (get_lppaca()->shared_proc)
-extern void __spin_yield(raw_spinlock_t *lock);
-extern void __rw_yield(raw_rwlock_t *lock);
-#else /* SPLPAR || ISERIES */
-#define __spin_yield(x) barrier()
-#define __rw_yield(x) barrier()
-#define SHARED_PROCESSOR 0
-#endif
-
-static inline void __raw_spin_lock(raw_spinlock_t *lock)
-{
- CLEAR_IO_SYNC;
- while (1) {
- if (likely(__spin_trylock(lock) == 0))
- break;
- do {
- HMT_low();
- if (SHARED_PROCESSOR)
- __spin_yield(lock);
- } while (unlikely(lock->slock != 0));
- HMT_medium();
- }
-}
-
-static inline
-void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags)
-{
- unsigned long flags_dis;
-
- CLEAR_IO_SYNC;
- while (1) {
- if (likely(__spin_trylock(lock) == 0))
- break;
- local_save_flags(flags_dis);
- local_irq_restore(flags);
- do {
- HMT_low();
- if (SHARED_PROCESSOR)
- __spin_yield(lock);
- } while (unlikely(lock->slock != 0));
- HMT_medium();
- local_irq_restore(flags_dis);
- }
-}
-
-static inline void __raw_spin_unlock(raw_spinlock_t *lock)
-{
- SYNC_IO;
- __asm__ __volatile__("# __raw_spin_unlock\n\t"
- LWSYNC_ON_SMP: : :"memory");
- lock->slock = 0;
-}
-
-#ifdef CONFIG_PPC64
-extern void __raw_spin_unlock_wait(raw_spinlock_t *lock);
-#else
-#define __raw_spin_unlock_wait(lock) \
- do { while (__raw_spin_is_locked(lock)) cpu_relax(); } while (0)
-#endif
-
-/*
- * Read-write spinlocks, allowing multiple readers
- * but only one writer.
- *
- * NOTE! it is quite common to have readers in interrupts
- * but no interrupt writers. For those circumstances we
- * can "mix" irq-safe locks - any writer needs to get a
- * irq-safe write-lock, but readers can get non-irqsafe
- * read-locks.
- */
-
-#define __raw_read_can_lock(rw) ((rw)->lock >= 0)
-#define __raw_write_can_lock(rw) (!(rw)->lock)
-
-#ifdef CONFIG_PPC64
-#define __DO_SIGN_EXTEND "extsw %0,%0\n"
-#define WRLOCK_TOKEN LOCK_TOKEN /* it's negative */
-#else
-#define __DO_SIGN_EXTEND
-#define WRLOCK_TOKEN (-1)
-#endif
-
-/*
- * This returns the old value in the lock + 1,
- * so we got a read lock if the return value is > 0.
- */
-static inline long __read_trylock(raw_rwlock_t *rw)
-{
- long tmp;
-
- __asm__ __volatile__(
-"1: lwarx %0,0,%1\n"
- __DO_SIGN_EXTEND
-" addic. %0,%0,1\n\
- ble- 2f\n"
- PPC405_ERR77(0,%1)
-" stwcx. %0,0,%1\n\
- bne- 1b\n\
- isync\n\
-2:" : "=&r" (tmp)
- : "r" (&rw->lock)
- : "cr0", "xer", "memory");
-
- return tmp;
-}
-
-/*
- * This returns the old value in the lock,
- * so we got the write lock if the return value is 0.
- */
-static inline long __write_trylock(raw_rwlock_t *rw)
-{
- long tmp, token;
-
- token = WRLOCK_TOKEN;
- __asm__ __volatile__(
-"1: lwarx %0,0,%2\n\
- cmpwi 0,%0,0\n\
- bne- 2f\n"
- PPC405_ERR77(0,%1)
-" stwcx. %1,0,%2\n\
- bne- 1b\n\
- isync\n\
-2:" : "=&r" (tmp)
- : "r" (token), "r" (&rw->lock)
- : "cr0", "memory");
-
- return tmp;
-}
-
-static inline void __raw_read_lock(raw_rwlock_t *rw)
-{
- while (1) {
- if (likely(__read_trylock(rw) > 0))
- break;
- do {
- HMT_low();
- if (SHARED_PROCESSOR)
- __rw_yield(rw);
- } while (unlikely(rw->lock < 0));
- HMT_medium();
- }
-}
-
-static inline void __raw_write_lock(raw_rwlock_t *rw)
-{
- while (1) {
- if (likely(__write_trylock(rw) == 0))
- break;
- do {
- HMT_low();
- if (SHARED_PROCESSOR)
- __rw_yield(rw);
- } while (unlikely(rw->lock != 0));
- HMT_medium();
- }
-}
-
-static inline int __raw_read_trylock(raw_rwlock_t *rw)
-{
- return __read_trylock(rw) > 0;
-}
-
-static inline int __raw_write_trylock(raw_rwlock_t *rw)
-{
- return __write_trylock(rw) == 0;
-}
-
-static inline void __raw_read_unlock(raw_rwlock_t *rw)
-{
- long tmp;
-
- __asm__ __volatile__(
- "# read_unlock\n\t"
- LWSYNC_ON_SMP
-"1: lwarx %0,0,%1\n\
- addic %0,%0,-1\n"
- PPC405_ERR77(0,%1)
-" stwcx. %0,0,%1\n\
- bne- 1b"
- : "=&r"(tmp)
- : "r"(&rw->lock)
- : "cr0", "memory");
-}
-
-static inline void __raw_write_unlock(raw_rwlock_t *rw)
-{
- __asm__ __volatile__("# write_unlock\n\t"
- LWSYNC_ON_SMP: : :"memory");
- rw->lock = 0;
-}
-
-#define _raw_spin_relax(lock) __spin_yield(lock)
-#define _raw_read_relax(lock) __rw_yield(lock)
-#define _raw_write_relax(lock) __rw_yield(lock)
-
-#endif /* __KERNEL__ */
-#endif /* __ASM_SPINLOCK_H */
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff