#include <asm/atomic.h>
#include <asm/rwlock.h>
#include <asm/page.h>
-#include <linux/config.h>
#include <linux/compiler.h>
-asmlinkage int printk(const char * fmt, ...)
- __attribute__ ((format (printf, 1, 2)));
-
/*
* Your basic SMP spinlocks, allowing only a single CPU anywhere
- */
-
-typedef struct {
- volatile unsigned int lock;
-#ifdef CONFIG_DEBUG_SPINLOCK
- unsigned magic;
-#endif
-} spinlock_t;
-
-#define SPINLOCK_MAGIC 0xdead4ead
-
-#ifdef CONFIG_DEBUG_SPINLOCK
-#define SPINLOCK_MAGIC_INIT , SPINLOCK_MAGIC
-#else
-#define SPINLOCK_MAGIC_INIT /* */
-#endif
-
-#define SPIN_LOCK_UNLOCKED (spinlock_t) { 1 SPINLOCK_MAGIC_INIT }
-
-#define spin_lock_init(x) do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
-
-/*
+ *
* 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.
+ *
+ * (the type definitions are in asm/spinlock_types.h)
*/
-#define spin_is_locked(x) (*(volatile signed char *)(&(x)->lock) <= 0)
-#define spin_unlock_wait(x) do { barrier(); } while(spin_is_locked(x))
+#define __raw_spin_is_locked(x) \
+ (*(volatile signed char *)(&(x)->slock) <= 0)
-#define spin_lock_string \
+#define __raw_spin_lock_string \
"\n1:\t" \
- "lock ; decb %0\n\t" \
+ LOCK_PREFIX " ; decb %0\n\t" \
"jns 3f\n" \
"2:\t" \
"rep;nop\n\t" \
"jmp 1b\n" \
"3:\n\t"
-#define spin_lock_string_flags \
+/*
+ * NOTE: there's an irqs-on section here, which normally would have to be
+ * irq-traced, but on CONFIG_TRACE_IRQFLAGS we never use
+ * __raw_spin_lock_string_flags().
+ */
+#define __raw_spin_lock_string_flags \
"\n1:\t" \
- "lock ; decb %0\n\t" \
- "jns 4f\n\t" \
+ LOCK_PREFIX " ; decb %0\n\t" \
+ "jns 5f\n" \
"2:\t" \
"testl $0x200, %1\n\t" \
- "jz 3f\n\t" \
- "sti\n\t" \
+ "jz 4f\n\t" \
+ "sti\n" \
"3:\t" \
"rep;nop\n\t" \
"cmpb $0, %0\n\t" \
"jle 3b\n\t" \
"cli\n\t" \
"jmp 1b\n" \
- "4:\n\t"
+ "4:\t" \
+ "rep;nop\n\t" \
+ "cmpb $0, %0\n\t" \
+ "jg 1b\n\t" \
+ "jmp 4b\n" \
+ "5:\n\t"
+
+static inline void __raw_spin_lock(raw_spinlock_t *lock)
+{
+ asm(__raw_spin_lock_string : "+m" (lock->slock) : : "memory");
+}
/*
- * This works. Despite all the confusion.
- * (except on PPro SMP or if we are using OOSTORE)
+ * It is easier for the lock validator if interrupts are not re-enabled
+ * in the middle of a lock-acquire. This is a performance feature anyway
+ * so we turn it off:
+ */
+#ifndef CONFIG_PROVE_LOCKING
+static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags)
+{
+ asm(__raw_spin_lock_string_flags : "+m" (lock->slock) : "r" (flags) : "memory");
+}
+#endif
+
+static inline int __raw_spin_trylock(raw_spinlock_t *lock)
+{
+ char oldval;
+ __asm__ __volatile__(
+ "xchgb %b0,%1"
+ :"=q" (oldval), "+m" (lock->slock)
+ :"0" (0) : "memory");
+ return oldval > 0;
+}
+
+/*
+ * __raw_spin_unlock based on writing $1 to the low byte.
+ * This method works. Despite all the confusion.
+ * (except on PPro SMP or if we are using OOSTORE, so we use xchgb there)
* (PPro errata 66, 92)
*/
-
+
#if !defined(CONFIG_X86_OOSTORE) && !defined(CONFIG_X86_PPRO_FENCE)
-#define spin_unlock_string \
+#define __raw_spin_unlock_string \
"movb $1,%0" \
- :"=m" (lock->lock) : : "memory"
+ :"+m" (lock->slock) : : "memory"
-static inline void _raw_spin_unlock(spinlock_t *lock)
+static inline void __raw_spin_unlock(raw_spinlock_t *lock)
{
-#ifdef CONFIG_DEBUG_SPINLOCK
- BUG_ON(lock->magic != SPINLOCK_MAGIC);
- BUG_ON(!spin_is_locked(lock));
-#endif
__asm__ __volatile__(
- spin_unlock_string
+ __raw_spin_unlock_string
);
}
#else
-#define spin_unlock_string \
+#define __raw_spin_unlock_string \
"xchgb %b0, %1" \
- :"=q" (oldval), "=m" (lock->lock) \
+ :"=q" (oldval), "+m" (lock->slock) \
:"0" (oldval) : "memory"
-static inline void _raw_spin_unlock(spinlock_t *lock)
+static inline void __raw_spin_unlock(raw_spinlock_t *lock)
{
char oldval = 1;
-#ifdef CONFIG_DEBUG_SPINLOCK
- BUG_ON(lock->magic != SPINLOCK_MAGIC);
- BUG_ON(!spin_is_locked(lock));
-#endif
- __asm__ __volatile__(
- spin_unlock_string
- );
-}
-
-#endif
-static inline int _raw_spin_trylock(spinlock_t *lock)
-{
- char oldval;
__asm__ __volatile__(
- "xchgb %b0,%1"
- :"=q" (oldval), "=m" (lock->lock)
- :"0" (0) : "memory");
- return oldval > 0;
+ __raw_spin_unlock_string
+ );
}
-static inline void _raw_spin_lock(spinlock_t *lock)
-{
-#ifdef CONFIG_DEBUG_SPINLOCK
- if (unlikely(lock->magic != SPINLOCK_MAGIC)) {
- printk("eip: %p\n", __builtin_return_address(0));
- BUG();
- }
#endif
- __asm__ __volatile__(
- spin_lock_string
- :"=m" (lock->lock) : : "memory");
-}
-static inline void _raw_spin_lock_flags (spinlock_t *lock, unsigned long flags)
-{
-#ifdef CONFIG_DEBUG_SPINLOCK
- if (unlikely(lock->magic != SPINLOCK_MAGIC)) {
- printk("eip: %p\n", __builtin_return_address(0));
- BUG();
- }
-#endif
- __asm__ __volatile__(
- spin_lock_string_flags
- :"=m" (lock->lock) : "r" (flags) : "memory");
-}
+#define __raw_spin_unlock_wait(lock) \
+ do { while (__raw_spin_is_locked(lock)) cpu_relax(); } while (0)
/*
* Read-write spinlocks, allowing multiple readers
* 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_DEBUG_SPINLOCK
- unsigned magic;
-#endif
-} rwlock_t;
-
-#define RWLOCK_MAGIC 0xdeaf1eed
-
-#ifdef CONFIG_DEBUG_SPINLOCK
-#define RWLOCK_MAGIC_INIT , RWLOCK_MAGIC
-#else
-#define RWLOCK_MAGIC_INIT /* */
-#endif
-
-#define RW_LOCK_UNLOCKED (rwlock_t) { RW_LOCK_BIAS RWLOCK_MAGIC_INIT }
-
-#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0)
-
-#define rwlock_is_locked(x) ((x)->lock != RW_LOCK_BIAS)
-
-/*
+ *
* On x86, we implement read-write locks as a 32-bit counter
* with the high bit (sign) being the "contended" bit.
*
*
* Changed to use the same technique as rw semaphores. See
* semaphore.h for details. -ben
+ *
+ * the helpers are in arch/i386/kernel/semaphore.c
+ */
+
+/**
+ * read_can_lock - would read_trylock() succeed?
+ * @lock: the rwlock in question.
*/
-/* the spinlock helpers are in arch/i386/kernel/semaphore.c */
+#define __raw_read_can_lock(x) ((int)(x)->lock > 0)
-static inline void _raw_read_lock(rwlock_t *rw)
+/**
+ * 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)
{
-#ifdef CONFIG_DEBUG_SPINLOCK
- BUG_ON(rw->magic != RWLOCK_MAGIC);
-#endif
__build_read_lock(rw, "__read_lock_failed");
}
-static inline void _raw_write_lock(rwlock_t *rw)
+static inline void __raw_write_lock(raw_rwlock_t *rw)
{
-#ifdef CONFIG_DEBUG_SPINLOCK
- BUG_ON(rw->magic != RWLOCK_MAGIC);
-#endif
__build_write_lock(rw, "__write_lock_failed");
}
-#define _raw_read_unlock(rw) asm volatile("lock ; incl %0" :"=m" ((rw)->lock) : : "memory")
-#define _raw_write_unlock(rw) asm volatile("lock ; addl $" RW_LOCK_BIAS_STR ",%0":"=m" ((rw)->lock) : : "memory")
+static inline int __raw_read_trylock(raw_rwlock_t *lock)
+{
+ atomic_t *count = (atomic_t *)lock;
+ atomic_dec(count);
+ if (atomic_read(count) >= 0)
+ return 1;
+ atomic_inc(count);
+ return 0;
+}
-static inline int _raw_write_trylock(rwlock_t *lock)
+static inline int __raw_write_trylock(raw_rwlock_t *lock)
{
atomic_t *count = (atomic_t *)lock;
if (atomic_sub_and_test(RW_LOCK_BIAS, count))
return 0;
}
+static inline void __raw_read_unlock(raw_rwlock_t *rw)
+{
+ asm volatile(LOCK_PREFIX "incl %0" :"+m" (rw->lock) : : "memory");
+}
+
+static inline void __raw_write_unlock(raw_rwlock_t *rw)
+{
+ asm volatile(LOCK_PREFIX "addl $" RW_LOCK_BIAS_STR ", %0"
+ : "+m" (rw->lock) : : "memory");
+}
+
#endif /* __ASM_SPINLOCK_H */
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