From 8a467a529f01c3471b195a0e8989c6177fe145ef Mon Sep 17 00:00:00 2001 From: Paul Mundt Date: Wed, 22 Aug 2007 10:34:31 +0900 Subject: [PATCH] sh: Overhaul spinlocks and rwlocks for SH-4A SMP. This rips out some of the old spinlock and rwlock behaviour that the SH-2 parts were using and reworks them for LL/SC semantics on the SH-4A. This is primarily only useful for SH-X3 multi-cores, but can also be used for building CONFIG_SMP=y testing kernels on SH-4A UP. Signed-off-by: Paul Mundt --- include/asm-sh/spinlock.h | 181 +++++++++++++++++++++++++------- include/asm-sh/spinlock_types.h | 11 +- 2 files changed, 146 insertions(+), 46 deletions(-) diff --git a/include/asm-sh/spinlock.h b/include/asm-sh/spinlock.h index 92f6e2008b2e..e793181d64da 100644 --- a/include/asm-sh/spinlock.h +++ b/include/asm-sh/spinlock.h @@ -2,6 +2,7 @@ * include/asm-sh/spinlock.h * * Copyright (C) 2002, 2003 Paul Mundt + * Copyright (C) 2006, 2007 Akio Idehara * * 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 @@ -10,17 +11,22 @@ #ifndef __ASM_SH_SPINLOCK_H #define __ASM_SH_SPINLOCK_H -#include -#include +/* + * The only locking implemented here uses SH-4A opcodes. For others, + * split this out as per atomic-*.h. + */ +#ifndef CONFIG_CPU_SH4A +#error "Need movli.l/movco.l for spinlocks" +#endif /* * Your basic SMP spinlocks, allowing only a single CPU anywhere */ -#define __raw_spin_is_locked(x) ((x)->lock != 0) +#define __raw_spin_is_locked(x) ((x)->lock <= 0) #define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock) #define __raw_spin_unlock_wait(x) \ - do { cpu_relax(); } while (__raw_spin_is_locked(x)) + do { cpu_relax(); } while ((x)->lock) /* * Simple spin lock operations. There are two variants, one clears IRQ's @@ -30,12 +36,19 @@ */ static inline void __raw_spin_lock(raw_spinlock_t *lock) { + unsigned long tmp; + unsigned long oldval; + __asm__ __volatile__ ( - "1:\n\t" - "tas.b @%0\n\t" - "bf/s 1b\n\t" - "nop\n\t" - : "=r" (lock->lock) + "1: \n\t" + "movli.l @%2, %0 ! __raw_spin_lock \n\t" + "mov %0, %1 \n\t" + "mov #0, %0 \n\t" + "movco.l %0, @%2 \n\t" + "bf 1b \n\t" + "cmp/pl %1 \n\t" + "bf 1b \n\t" + : "=&z" (tmp), "=&r" (oldval) : "r" (&lock->lock) : "t", "memory" ); @@ -43,12 +56,36 @@ static inline void __raw_spin_lock(raw_spinlock_t *lock) static inline void __raw_spin_unlock(raw_spinlock_t *lock) { - //assert_spin_locked(lock); + unsigned long tmp; - lock->lock = 0; + __asm__ __volatile__ ( + "mov #1, %0 ! __raw_spin_unlock \n\t" + "mov.l %0, @%1 \n\t" + : "=&z" (tmp) + : "r" (&lock->lock) + : "t", "memory" + ); } -#define __raw_spin_trylock(x) (!test_and_set_bit(0, &(x)->lock)) +static inline int __raw_spin_trylock(raw_spinlock_t *lock) +{ + unsigned long tmp, oldval; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%2, %0 ! __raw_spin_trylock \n\t" + "mov %0, %1 \n\t" + "mov #0, %0 \n\t" + "movco.l %0, @%2 \n\t" + "bf 1b \n\t" + "synco \n\t" + : "=&z" (tmp), "=&r" (oldval) + : "r" (&lock->lock) + : "t", "memory" + ); + + return oldval; +} /* * Read-write spinlocks, allowing multiple readers but only one writer. @@ -59,58 +96,124 @@ static inline void __raw_spin_unlock(raw_spinlock_t *lock) * read-locks. */ +/** + * read_can_lock - would read_trylock() succeed? + * @lock: the rwlock in question. + */ +#define __raw_read_can_lock(x) ((x)->lock > 0) + +/** + * write_can_lock - would write_trylock() succeed? + * @lock: the rwlock in question. + */ +#define __raw_write_can_lock(x) ((x)->lock == RW_LOCK_BIAS) + static inline void __raw_read_lock(raw_rwlock_t *rw) { - __raw_spin_lock(&rw->lock); - - atomic_inc(&rw->counter); + unsigned long tmp; - __raw_spin_unlock(&rw->lock); + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%1, %0 ! __raw_read_lock \n\t" + "cmp/pl %0 \n\t" + "bf 1b \n\t" + "add #-1, %0 \n\t" + "movco.l %0, @%1 \n\t" + "bf 1b \n\t" + : "=&z" (tmp) + : "r" (&rw->lock) + : "t", "memory" + ); } static inline void __raw_read_unlock(raw_rwlock_t *rw) { - __raw_spin_lock(&rw->lock); - - atomic_dec(&rw->counter); + unsigned long tmp; - __raw_spin_unlock(&rw->lock); + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%1, %0 ! __raw_read_unlock \n\t" + "add #1, %0 \n\t" + "movco.l %0, @%1 \n\t" + "bf 1b \n\t" + : "=&z" (tmp) + : "r" (&rw->lock) + : "t", "memory" + ); } static inline void __raw_write_lock(raw_rwlock_t *rw) { - __raw_spin_lock(&rw->lock); - atomic_set(&rw->counter, -1); + unsigned long tmp; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%1, %0 ! __raw_write_lock \n\t" + "cmp/hs %2, %0 \n\t" + "bf 1b \n\t" + "sub %2, %0 \n\t" + "movco.l %0, @%1 \n\t" + "bf 1b \n\t" + : "=&z" (tmp) + : "r" (&rw->lock), "r" (RW_LOCK_BIAS) + : "t", "memory" + ); } static inline void __raw_write_unlock(raw_rwlock_t *rw) { - atomic_set(&rw->counter, 0); - __raw_spin_unlock(&rw->lock); + __asm__ __volatile__ ( + "mov.l %1, @%0 ! __raw_write_unlock \n\t" + : + : "r" (&rw->lock), "r" (RW_LOCK_BIAS) + : "t", "memory" + ); } -static inline int __raw_write_can_lock(raw_rwlock_t *rw) +static inline int __raw_read_trylock(raw_rwlock_t *rw) { - return (atomic_read(&rw->counter) == RW_LOCK_BIAS); -} + unsigned long tmp, oldval; -static inline int __raw_read_trylock(raw_rwlock_t *lock) -{ - atomic_t *count = (atomic_t*)lock; - if (atomic_dec_return(count) >= 0) - return 1; - atomic_inc(count); - return 0; + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%2, %0 ! __raw_read_trylock \n\t" + "mov %0, %1 \n\t" + "cmp/pl %0 \n\t" + "bf 2f \n\t" + "add #-1, %0 \n\t" + "movco.l %0, @%2 \n\t" + "bf 1b \n\t" + "2: \n\t" + "synco \n\t" + : "=&z" (tmp), "=&r" (oldval) + : "r" (&rw->lock) + : "t", "memory" + ); + + return (oldval > 0); } static inline int __raw_write_trylock(raw_rwlock_t *rw) { - if (atomic_sub_and_test(RW_LOCK_BIAS, &rw->counter)) - return 1; - - atomic_add(RW_LOCK_BIAS, &rw->counter); + unsigned long tmp, oldval; + + __asm__ __volatile__ ( + "1: \n\t" + "movli.l @%2, %0 ! __raw_write_trylock \n\t" + "mov %0, %1 \n\t" + "cmp/hs %3, %0 \n\t" + "bf 2f \n\t" + "sub %3, %0 \n\t" + "2: \n\t" + "movco.l %0, @%2 \n\t" + "bf 1b \n\t" + "synco \n\t" + : "=&z" (tmp), "=&r" (oldval) + : "r" (&rw->lock), "r" (RW_LOCK_BIAS) + : "t", "memory" + ); - return 0; + return (oldval > (RW_LOCK_BIAS - 1)); } #define _raw_spin_relax(lock) cpu_relax() diff --git a/include/asm-sh/spinlock_types.h b/include/asm-sh/spinlock_types.h index 5c58134f2c4e..b4d244e7b60c 100644 --- a/include/asm-sh/spinlock_types.h +++ b/include/asm-sh/spinlock_types.h @@ -6,19 +6,16 @@ #endif typedef struct { - volatile unsigned long lock; + volatile unsigned int lock; } raw_spinlock_t; -#define __RAW_SPIN_LOCK_UNLOCKED { 1 } - -#include +#define __RAW_SPIN_LOCK_UNLOCKED { 1 } typedef struct { - raw_spinlock_t lock; - atomic_t counter; + volatile unsigned int lock; } raw_rwlock_t; #define RW_LOCK_BIAS 0x01000000 -#define __RAW_RW_LOCK_UNLOCKED { { 0 }, { RW_LOCK_BIAS } } +#define __RAW_RW_LOCK_UNLOCKED { RW_LOCK_BIAS } #endif -- 2.39.2