patch-2.1.30 linux/include/asm-i386/spinlock.h

• Lines: 97
• Date: Thu Mar 20 11:06:29 1997
• Orig file: v2.1.29/linux/include/asm-i386/spinlock.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.29/linux/include/asm-i386/spinlock.h linux/include/asm-i386/spinlock.h
@@ -0,0 +1,96 @@
+#ifndef __ASM_SPINLOCK_H
+#define __ASM_SPINLOCK_H
+
+#ifndef __SMP__
+
+typedef struct { } spinlock_t;
+#define SPIN_LOCK_UNLOCKED { }
+
+#define spin_lock_init(lock)	do { } while(0)
+#define spin_lock(lock)		do { } while(0)
+#define spin_trylock(lock)	do { } while(0)
+#define spin_unlock(lock)	do { } while(0)
+#define spin_lock_irq(lock)	cli()
+#define spin_unlock_irq(lock)	sti()
+
+#define spin_lock_irqsave(lock, flags) \
+	do { save_flags(flags); cli(); } while (0)
+#define spin_unlock_irqrestore(lock, flags) \
+	restore_flags(flags)
+
+#else
+
+/* 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.
+ */
+
+typedef struct {
+	volatile unsigned int lock;
+	unsigned long previous;
+} spinlock_t;
+
+#define SPIN_LOCK_UNLOCKED { 0, 0 }
+
+typedef struct { unsigned long a[100]; } __dummy_lock_t;
+#define __dummy_lock(lock) (*(__dummy_lock_t *)(lock))
+
+#define spin_lock(lock) \
+__asm__ __volatile__( \
+	"jmp 2f\n" \
+	"1:\t" \
+	"testb $1,%0\n\t" \
+	"jne 1b\n" \
+	"2:\t" \
+	"lock ; btsl $0,%0\n\t" \
+	"jc 1b" \
+	:"=m" (__dummy_lock(lock)))
+
+#define spin_unlock(lock) \
+__asm__ __volatile__( \
+	"lock ; btrl $0,%0" \
+	:"=m" (__dummy_lock(lock)))
+
+#undef spin_lock
+static inline void spin_lock(spinlock_t * lock)
+{
+	__label__ l1;
+	int stuck = 10000000;
+l1:
+	__asm__ __volatile__(
+		"jmp 2f\n"
+		"1:\t"
+		"decl %1\n\t"
+		"je 3f\n\t"
+		"testb $1,%0\n\t"
+		"jne 1b\n"
+		"2:\t"
+		"lock ; btsl $0,%0\n\t"
+		"jc 1b\n"
+		"3:"
+		:"=m" (__dummy_lock(lock)),
+		 "=r" (stuck)
+		:"1" (stuck));
+	if (!stuck) {
+		printk("spinlock stuck at %p (%lx)\n",&&l1,lock->previous);
+	} else
+		lock->previous = (unsigned long) &&l1;
+}
+
+#define spin_trylock(lock) (!set_bit(0,(lock)))
+
+#define spin_lock_irq(lock) \
+	do { __cli(); spin_lock(lock); } while (0)
+
+#define spin_unlock_irq(lock) \
+	do { spin_unlock(lock); __sti(); } while (0)
+
+#define spin_lock_irqsave(lock, flags) \
+	do { __save_flags(flags); __cli(); spin_lock(lock); } while (0)
+
+#define spin_unlock_irqrestore(lock, flags) \
+	do { spin_unlock(lock); __restore_flags(flags); } while (0)
+
+#endif /* SMP */
+#endif /* __ASM_SPINLOCK_H */