From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- include/asm-mips/spinlock.h | 299 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 299 insertions(+) create mode 100644 include/asm-mips/spinlock.h (limited to 'include/asm-mips/spinlock.h') diff --git a/include/asm-mips/spinlock.h b/include/asm-mips/spinlock.h new file mode 100644 index 00000000000..114d3eb98a6 --- /dev/null +++ b/include/asm-mips/spinlock.h @@ -0,0 +1,299 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 1999, 2000 by Ralf Baechle + * Copyright (C) 1999, 2000 Silicon Graphics, Inc. + */ +#ifndef _ASM_SPINLOCK_H +#define _ASM_SPINLOCK_H + +#include +#include + +/* + * Your basic SMP spinlocks, allowing only a single CPU anywhere + */ + +typedef struct { + volatile unsigned int lock; +#ifdef CONFIG_PREEMPT + unsigned int break_lock; +#endif +} spinlock_t; + +#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 } + +#define spin_lock_init(x) do { (x)->lock = 0; } while(0) + +#define spin_is_locked(x) ((x)->lock != 0) +#define spin_unlock_wait(x) do { barrier(); } while ((x)->lock) +#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock) + +/* + * Simple spin lock operations. There are two variants, one clears IRQ's + * on the local processor, one does not. + * + * We make no fairness assumptions. They have a cost. + */ + +static inline void _raw_spin_lock(spinlock_t *lock) +{ + unsigned int tmp; + + if (R10000_LLSC_WAR) { + __asm__ __volatile__( + " .set noreorder # _raw_spin_lock \n" + "1: ll %1, %2 \n" + " bnez %1, 1b \n" + " li %1, 1 \n" + " sc %1, %0 \n" + " beqzl %1, 1b \n" + " nop \n" + " sync \n" + " .set reorder \n" + : "=m" (lock->lock), "=&r" (tmp) + : "m" (lock->lock) + : "memory"); + } else { + __asm__ __volatile__( + " .set noreorder # _raw_spin_lock \n" + "1: ll %1, %2 \n" + " bnez %1, 1b \n" + " li %1, 1 \n" + " sc %1, %0 \n" + " beqz %1, 1b \n" + " sync \n" + " .set reorder \n" + : "=m" (lock->lock), "=&r" (tmp) + : "m" (lock->lock) + : "memory"); + } +} + +static inline void _raw_spin_unlock(spinlock_t *lock) +{ + __asm__ __volatile__( + " .set noreorder # _raw_spin_unlock \n" + " sync \n" + " sw $0, %0 \n" + " .set\treorder \n" + : "=m" (lock->lock) + : "m" (lock->lock) + : "memory"); +} + +static inline unsigned int _raw_spin_trylock(spinlock_t *lock) +{ + unsigned int temp, res; + + if (R10000_LLSC_WAR) { + __asm__ __volatile__( + " .set noreorder # _raw_spin_trylock \n" + "1: ll %0, %3 \n" + " ori %2, %0, 1 \n" + " sc %2, %1 \n" + " beqzl %2, 1b \n" + " nop \n" + " andi %2, %0, 1 \n" + " sync \n" + " .set reorder" + : "=&r" (temp), "=m" (lock->lock), "=&r" (res) + : "m" (lock->lock) + : "memory"); + } else { + __asm__ __volatile__( + " .set noreorder # _raw_spin_trylock \n" + "1: ll %0, %3 \n" + " ori %2, %0, 1 \n" + " sc %2, %1 \n" + " beqz %2, 1b \n" + " andi %2, %0, 1 \n" + " sync \n" + " .set reorder" + : "=&r" (temp), "=m" (lock->lock), "=&r" (res) + : "m" (lock->lock) + : "memory"); + } + + return res == 0; +} + +/* + * 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. + */ + +typedef struct { + volatile unsigned int lock; +#ifdef CONFIG_PREEMPT + unsigned int break_lock; +#endif +} rwlock_t; + +#define RW_LOCK_UNLOCKED (rwlock_t) { 0 } + +#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0) + +static inline void _raw_read_lock(rwlock_t *rw) +{ + unsigned int tmp; + + if (R10000_LLSC_WAR) { + __asm__ __volatile__( + " .set noreorder # _raw_read_lock \n" + "1: ll %1, %2 \n" + " bltz %1, 1b \n" + " addu %1, 1 \n" + " sc %1, %0 \n" + " beqzl %1, 1b \n" + " nop \n" + " sync \n" + " .set reorder \n" + : "=m" (rw->lock), "=&r" (tmp) + : "m" (rw->lock) + : "memory"); + } else { + __asm__ __volatile__( + " .set noreorder # _raw_read_lock \n" + "1: ll %1, %2 \n" + " bltz %1, 1b \n" + " addu %1, 1 \n" + " sc %1, %0 \n" + " beqz %1, 1b \n" + " sync \n" + " .set reorder \n" + : "=m" (rw->lock), "=&r" (tmp) + : "m" (rw->lock) + : "memory"); + } +} + +/* Note the use of sub, not subu which will make the kernel die with an + overflow exception if we ever try to unlock an rwlock that is already + unlocked or is being held by a writer. */ +static inline void _raw_read_unlock(rwlock_t *rw) +{ + unsigned int tmp; + + if (R10000_LLSC_WAR) { + __asm__ __volatile__( + "1: ll %1, %2 # _raw_read_unlock \n" + " sub %1, 1 \n" + " sc %1, %0 \n" + " beqzl %1, 1b \n" + " sync \n" + : "=m" (rw->lock), "=&r" (tmp) + : "m" (rw->lock) + : "memory"); + } else { + __asm__ __volatile__( + " .set noreorder # _raw_read_unlock \n" + "1: ll %1, %2 \n" + " sub %1, 1 \n" + " sc %1, %0 \n" + " beqz %1, 1b \n" + " sync \n" + " .set reorder \n" + : "=m" (rw->lock), "=&r" (tmp) + : "m" (rw->lock) + : "memory"); + } +} + +static inline void _raw_write_lock(rwlock_t *rw) +{ + unsigned int tmp; + + if (R10000_LLSC_WAR) { + __asm__ __volatile__( + " .set noreorder # _raw_write_lock \n" + "1: ll %1, %2 \n" + " bnez %1, 1b \n" + " lui %1, 0x8000 \n" + " sc %1, %0 \n" + " beqzl %1, 1b \n" + " nop \n" + " sync \n" + " .set reorder \n" + : "=m" (rw->lock), "=&r" (tmp) + : "m" (rw->lock) + : "memory"); + } else { + __asm__ __volatile__( + " .set noreorder # _raw_write_lock \n" + "1: ll %1, %2 \n" + " bnez %1, 1b \n" + " lui %1, 0x8000 \n" + " sc %1, %0 \n" + " beqz %1, 1b \n" + " nop \n" + " sync \n" + " .set reorder \n" + : "=m" (rw->lock), "=&r" (tmp) + : "m" (rw->lock) + : "memory"); + } +} + +static inline void _raw_write_unlock(rwlock_t *rw) +{ + __asm__ __volatile__( + " sync # _raw_write_unlock \n" + " sw $0, %0 \n" + : "=m" (rw->lock) + : "m" (rw->lock) + : "memory"); +} + +#define _raw_read_trylock(lock) generic_raw_read_trylock(lock) + +static inline int _raw_write_trylock(rwlock_t *rw) +{ + unsigned int tmp; + int ret; + + if (R10000_LLSC_WAR) { + __asm__ __volatile__( + " .set noreorder # _raw_write_trylock \n" + " li %2, 0 \n" + "1: ll %1, %3 \n" + " bnez %1, 2f \n" + " lui %1, 0x8000 \n" + " sc %1, %0 \n" + " beqzl %1, 1b \n" + " nop \n" + " sync \n" + " li %2, 1 \n" + " .set reorder \n" + "2: \n" + : "=m" (rw->lock), "=&r" (tmp), "=&r" (ret) + : "m" (rw->lock) + : "memory"); + } else { + __asm__ __volatile__( + " .set noreorder # _raw_write_trylock \n" + " li %2, 0 \n" + "1: ll %1, %3 \n" + " bnez %1, 2f \n" + " lui %1, 0x8000 \n" + " sc %1, %0 \n" + " beqz %1, 1b \n" + " sync \n" + " li %2, 1 \n" + " .set reorder \n" + "2: \n" + : "=m" (rw->lock), "=&r" (tmp), "=&r" (ret) + : "m" (rw->lock) + : "memory"); + } + + return ret; +} + +#endif /* _ASM_SPINLOCK_H */ -- cgit v1.2.3