--- /dev/null
+#ifndef __ASM_SPINLOCK_H
+#define __ASM_SPINLOCK_H
+
+#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.
+ */
+
+#define spin_is_locked(x) (*(volatile signed char *)(&(x)->lock) <= 0)
+#define spin_unlock_wait(x) do { barrier(); } while(spin_is_locked(x))
+
+#define spin_lock_string \
+ "\n1:\t" \
+ "lock ; decb %0\n\t" \
+ "jns 3f\n" \
+ "2:\t" \
+ "rep;nop\n\t" \
+ "cmpb $0,%0\n\t" \
+ "jle 2b\n\t" \
+ "jmp 1b\n" \
+ "3:\n\t"
+
+#define spin_lock_string_flags \
+ "\n1:\t" \
+ "lock ; decb %0\n\t" \
+ "jns 4f\n\t" \
+ "2:\t" \
+ "testl $0x200, %1\n\t" \
+ "jz 3f\n\t" \
+ "#sti\n\t" \
+ "3:\t" \
+ "rep;nop\n\t" \
+ "cmpb $0, %0\n\t" \
+ "jle 3b\n\t" \
+ "#cli\n\t" \
+ "jmp 1b\n" \
+ "4:\n\t"
+
+/*
+ * This works. Despite all the confusion.
+ * (except on PPro SMP or if we are using OOSTORE)
+ * (PPro errata 66, 92)
+ */
+
+#if !defined(CONFIG_X86_OOSTORE) && !defined(CONFIG_X86_PPRO_FENCE)
+
+#define spin_unlock_string \
+ "movb $1,%0" \
+ :"=m" (lock->lock) : : "memory"
+
+
+static inline void _raw_spin_unlock(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
+ );
+}
+
+#else
+
+#define spin_unlock_string \
+ "xchgb %b0, %1" \
+ :"=q" (oldval), "=m" (lock->lock) \
+ :"0" (oldval) : "memory"
+
+static inline void _raw_spin_unlock(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;
+}
+
+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");
+}
+
+/*
+ * 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_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.
+ *
+ * The inline assembly is non-obvious. Think about it.
+ *
+ * Changed to use the same technique as rw semaphores. See
+ * semaphore.h for details. -ben
+ */
+/* the spinlock helpers are in arch/i386/kernel/semaphore.c */
+
+static inline void _raw_read_lock(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)
+{
+#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_write_trylock(rwlock_t *lock)
+{
+ atomic_t *count = (atomic_t *)lock;
+ if (atomic_sub_and_test(RW_LOCK_BIAS, count))
+ return 1;
+ atomic_add(RW_LOCK_BIAS, count);
+ return 0;
+}
+
+#endif /* __ASM_SPINLOCK_H */
projects / xen.git / commitdiff