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Diffstat (limited to 'arch/mips/include/asm/spinlock.h')
| -rw-r--r-- | arch/mips/include/asm/spinlock.h | 487 |
1 files changed, 487 insertions, 0 deletions
diff --git a/arch/mips/include/asm/spinlock.h b/arch/mips/include/asm/spinlock.h new file mode 100644 index 0000000..1a1f320 --- /dev/null +++ b/arch/mips/include/asm/spinlock.h @@ -0,0 +1,487 @@ +/* + * 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, 06 Ralf Baechle (ralf@linux-mips.org) + * Copyright (C) 1999, 2000 Silicon Graphics, Inc. + */ +#ifndef _ASM_SPINLOCK_H +#define _ASM_SPINLOCK_H + +#include <linux/compiler.h> + +#include <asm/barrier.h> +#include <asm/war.h> + +/* + * Your basic SMP spinlocks, allowing only a single CPU anywhere + * + * Simple spin lock operations. There are two variants, one clears IRQ's + * on the local processor, one does not. + * + * These are fair FIFO ticket locks + * + * (the type definitions are in asm/spinlock_types.h) + */ + + +/* + * Ticket locks are conceptually two parts, one indicating the current head of + * the queue, and the other indicating the current tail. The lock is acquired + * by atomically noting the tail and incrementing it by one (thus adding + * ourself to the queue and noting our position), then waiting until the head + * becomes equal to the the initial value of the tail. + */ + +static inline int __raw_spin_is_locked(raw_spinlock_t *lock) +{ + unsigned int counters = ACCESS_ONCE(lock->lock); + + return ((counters >> 14) ^ counters) & 0x1fff; +} + +#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock) +#define __raw_spin_unlock_wait(x) \ + while (__raw_spin_is_locked(x)) { cpu_relax(); } + +static inline int __raw_spin_is_contended(raw_spinlock_t *lock) +{ + unsigned int counters = ACCESS_ONCE(lock->lock); + + return (((counters >> 14) - counters) & 0x1fff) > 1; +} + +static inline void __raw_spin_lock(raw_spinlock_t *lock) +{ + int my_ticket; + int tmp; + + if (R10000_LLSC_WAR) { + __asm__ __volatile__ ( + " .set push # __raw_spin_lock \n" + " .set noreorder \n" + " \n" + "1: ll %[ticket], %[ticket_ptr] \n" + " addiu %[my_ticket], %[ticket], 0x4000 \n" + " sc %[my_ticket], %[ticket_ptr] \n" + " beqzl %[my_ticket], 1b \n" + " nop \n" + " srl %[my_ticket], %[ticket], 14 \n" + " andi %[my_ticket], %[my_ticket], 0x1fff \n" + " andi %[ticket], %[ticket], 0x1fff \n" + " bne %[ticket], %[my_ticket], 4f \n" + " subu %[ticket], %[my_ticket], %[ticket] \n" + "2: \n" + " .subsection 2 \n" + "4: andi %[ticket], %[ticket], 0x1fff \n" + "5: sll %[ticket], 5 \n" + " \n" + "6: bnez %[ticket], 6b \n" + " subu %[ticket], 1 \n" + " \n" + " lw %[ticket], %[ticket_ptr] \n" + " andi %[ticket], %[ticket], 0x1fff \n" + " beq %[ticket], %[my_ticket], 2b \n" + " subu %[ticket], %[my_ticket], %[ticket] \n" + " b 5b \n" + " subu %[ticket], %[ticket], 1 \n" + " .previous \n" + " .set pop \n" + : [ticket_ptr] "+m" (lock->lock), + [ticket] "=&r" (tmp), + [my_ticket] "=&r" (my_ticket)); + } else { + __asm__ __volatile__ ( + " .set push # __raw_spin_lock \n" + " .set noreorder \n" + " \n" + " ll %[ticket], %[ticket_ptr] \n" + "1: addiu %[my_ticket], %[ticket], 0x4000 \n" + " sc %[my_ticket], %[ticket_ptr] \n" + " beqz %[my_ticket], 3f \n" + " nop \n" + " srl %[my_ticket], %[ticket], 14 \n" + " andi %[my_ticket], %[my_ticket], 0x1fff \n" + " andi %[ticket], %[ticket], 0x1fff \n" + " bne %[ticket], %[my_ticket], 4f \n" + " subu %[ticket], %[my_ticket], %[ticket] \n" + "2: \n" + " .subsection 2 \n" + "3: b 1b \n" + " ll %[ticket], %[ticket_ptr] \n" + " \n" + "4: andi %[ticket], %[ticket], 0x1fff \n" + "5: sll %[ticket], 5 \n" + " \n" + "6: bnez %[ticket], 6b \n" + " subu %[ticket], 1 \n" + " \n" + " lw %[ticket], %[ticket_ptr] \n" + " andi %[ticket], %[ticket], 0x1fff \n" + " beq %[ticket], %[my_ticket], 2b \n" + " subu %[ticket], %[my_ticket], %[ticket] \n" + " b 5b \n" + " subu %[ticket], %[ticket], 1 \n" + " .previous \n" + " .set pop \n" + : [ticket_ptr] "+m" (lock->lock), + [ticket] "=&r" (tmp), + [my_ticket] "=&r" (my_ticket)); + } + + smp_llsc_mb(); +} + +static inline void __raw_spin_unlock(raw_spinlock_t *lock) +{ + int tmp; + + smp_llsc_mb(); + + if (R10000_LLSC_WAR) { + __asm__ __volatile__ ( + " # __raw_spin_unlock \n" + "1: ll %[ticket], %[ticket_ptr] \n" + " addiu %[ticket], %[ticket], 1 \n" + " ori %[ticket], %[ticket], 0x2000 \n" + " xori %[ticket], %[ticket], 0x2000 \n" + " sc %[ticket], %[ticket_ptr] \n" + " beqzl %[ticket], 1b \n" + : [ticket_ptr] "+m" (lock->lock), + [ticket] "=&r" (tmp)); + } else { + __asm__ __volatile__ ( + " .set push # __raw_spin_unlock \n" + " .set noreorder \n" + " \n" + " ll %[ticket], %[ticket_ptr] \n" + "1: addiu %[ticket], %[ticket], 1 \n" + " ori %[ticket], %[ticket], 0x2000 \n" + " xori %[ticket], %[ticket], 0x2000 \n" + " sc %[ticket], %[ticket_ptr] \n" + " beqz %[ticket], 2f \n" + " nop \n" + " \n" + " .subsection 2 \n" + "2: b 1b \n" + " ll %[ticket], %[ticket_ptr] \n" + " .previous \n" + " .set pop \n" + : [ticket_ptr] "+m" (lock->lock), + [ticket] "=&r" (tmp)); + } +} + +static inline unsigned int __raw_spin_trylock(raw_spinlock_t *lock) +{ + int tmp, tmp2, tmp3; + + if (R10000_LLSC_WAR) { + __asm__ __volatile__ ( + " .set push # __raw_spin_trylock \n" + " .set noreorder \n" + " \n" + "1: ll %[ticket], %[ticket_ptr] \n" + " srl %[my_ticket], %[ticket], 14 \n" + " andi %[my_ticket], %[my_ticket], 0x1fff \n" + " andi %[now_serving], %[ticket], 0x1fff \n" + " bne %[my_ticket], %[now_serving], 3f \n" + " addiu %[ticket], %[ticket], 0x4000 \n" + " sc %[ticket], %[ticket_ptr] \n" + " beqzl %[ticket], 1b \n" + " li %[ticket], 1 \n" + "2: \n" + " .subsection 2 \n" + "3: b 2b \n" + " li %[ticket], 0 \n" + " .previous \n" + " .set pop \n" + : [ticket_ptr] "+m" (lock->lock), + [ticket] "=&r" (tmp), + [my_ticket] "=&r" (tmp2), + [now_serving] "=&r" (tmp3)); + } else { + __asm__ __volatile__ ( + " .set push # __raw_spin_trylock \n" + " .set noreorder \n" + " \n" + " ll %[ticket], %[ticket_ptr] \n" + "1: srl %[my_ticket], %[ticket], 14 \n" + " andi %[my_ticket], %[my_ticket], 0x1fff \n" + " andi %[now_serving], %[ticket], 0x1fff \n" + " bne %[my_ticket], %[now_serving], 3f \n" + " addiu %[ticket], %[ticket], 0x4000 \n" + " sc %[ticket], %[ticket_ptr] \n" + " beqz %[ticket], 4f \n" + " li %[ticket], 1 \n" + "2: \n" + " .subsection 2 \n" + "3: b 2b \n" + " li %[ticket], 0 \n" + "4: b 1b \n" + " ll %[ticket], %[ticket_ptr] \n" + " .previous \n" + " .set pop \n" + : [ticket_ptr] "+m" (lock->lock), + [ticket] "=&r" (tmp), + [my_ticket] "=&r" (tmp2), + [now_serving] "=&r" (tmp3)); + } + + smp_llsc_mb(); + + return tmp; +} + +/* + * 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. + */ + +/* + * read_can_lock - would read_trylock() succeed? + * @lock: the rwlock in question. + */ +#define __raw_read_can_lock(rw) ((rw)->lock >= 0) + +/* + * write_can_lock - would write_trylock() succeed? + * @lock: the rwlock in question. + */ +#define __raw_write_can_lock(rw) (!(rw)->lock) + +static inline void __raw_read_lock(raw_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" + " .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, 2f \n" + " addu %1, 1 \n" + " sc %1, %0 \n" + " beqz %1, 1b \n" + " nop \n" + " .subsection 2 \n" + "2: ll %1, %2 \n" + " bltz %1, 2b \n" + " addu %1, 1 \n" + " b 1b \n" + " nop \n" + " .previous \n" + " .set reorder \n" + : "=m" (rw->lock), "=&r" (tmp) + : "m" (rw->lock) + : "memory"); + } + + smp_llsc_mb(); +} + +/* 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(raw_rwlock_t *rw) +{ + unsigned int tmp; + + smp_llsc_mb(); + + 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" + : "=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, 2f \n" + " nop \n" + " .subsection 2 \n" + "2: b 1b \n" + " nop \n" + " .previous \n" + " .set reorder \n" + : "=m" (rw->lock), "=&r" (tmp) + : "m" (rw->lock) + : "memory"); + } +} + +static inline void __raw_write_lock(raw_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" + " .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, 2f \n" + " lui %1, 0x8000 \n" + " sc %1, %0 \n" + " beqz %1, 2f \n" + " nop \n" + " .subsection 2 \n" + "2: ll %1, %2 \n" + " bnez %1, 2b \n" + " lui %1, 0x8000 \n" + " b 1b \n" + " nop \n" + " .previous \n" + " .set reorder \n" + : "=m" (rw->lock), "=&r" (tmp) + : "m" (rw->lock) + : "memory"); + } + + smp_llsc_mb(); +} + +static inline void __raw_write_unlock(raw_rwlock_t *rw) +{ + smp_mb(); + + __asm__ __volatile__( + " # __raw_write_unlock \n" + " sw $0, %0 \n" + : "=m" (rw->lock) + : "m" (rw->lock) + : "memory"); +} + +static inline int __raw_read_trylock(raw_rwlock_t *rw) +{ + unsigned int tmp; + int ret; + + if (R10000_LLSC_WAR) { + __asm__ __volatile__( + " .set noreorder # __raw_read_trylock \n" + " li %2, 0 \n" + "1: ll %1, %3 \n" + " bltz %1, 2f \n" + " addu %1, 1 \n" + " sc %1, %0 \n" + " .set reorder \n" + " beqzl %1, 1b \n" + " nop \n" + __WEAK_LLSC_MB + " li %2, 1 \n" + "2: \n" + : "=m" (rw->lock), "=&r" (tmp), "=&r" (ret) + : "m" (rw->lock) + : "memory"); + } else { + __asm__ __volatile__( + " .set noreorder # __raw_read_trylock \n" + " li %2, 0 \n" + "1: ll %1, %3 \n" + " bltz %1, 2f \n" + " addu %1, 1 \n" + " sc %1, %0 \n" + " beqz %1, 1b \n" + " nop \n" + " .set reorder \n" + __WEAK_LLSC_MB + " li %2, 1 \n" + "2: \n" + : "=m" (rw->lock), "=&r" (tmp), "=&r" (ret) + : "m" (rw->lock) + : "memory"); + } + + return ret; +} + +static inline int __raw_write_trylock(raw_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" + __WEAK_LLSC_MB + " 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, 3f \n" + " li %2, 1 \n" + "2: \n" + __WEAK_LLSC_MB + " .subsection 2 \n" + "3: b 1b \n" + " li %2, 0 \n" + " .previous \n" + " .set reorder \n" + : "=m" (rw->lock), "=&r" (tmp), "=&r" (ret) + : "m" (rw->lock) + : "memory"); + } + + return ret; +} + + +#define _raw_spin_relax(lock) cpu_relax() +#define _raw_read_relax(lock) cpu_relax() +#define _raw_write_relax(lock) cpu_relax() + +#endif /* _ASM_SPINLOCK_H */ |