patch-2.1.48 linux/include/asm-ppc/spinlock.h

• Lines: 108
• Date: Thu Jul 31 13:09:18 1997
• Orig file: v2.1.47/linux/include/asm-ppc/spinlock.h
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.47/linux/include/asm-ppc/spinlock.h linux/include/asm-ppc/spinlock.h
@@ -0,0 +1,107 @@
+#ifndef __ASM_SPINLOCK_H
+#define __ASM_SPINLOCK_H
+
+#ifndef __SMP__
+
+typedef struct { int blah; } 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)
+
+/*
+ * 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 { int fred; } rwlock_t;
+#define RW_LOCK_UNLOCKED { }
+
+#define read_lock(lock)		do { } while(0)
+#define read_unlock(lock)	do { } while(0)
+#define write_lock(lock)	do { } while(0)
+#define write_unlock(lock)	do { } while(0)
+#define read_lock_irq(lock)	cli()
+#define read_unlock_irq(lock)	sti()
+#define write_lock_irq(lock)	cli()
+#define write_unlock_irq(lock)	sti()
+
+#define read_lock_irqsave(lock, flags)	\
+	do { save_flags(flags); cli(); } while (0)
+#define read_unlock_irqrestore(lock, flags) \
+	restore_flags(flags)
+#define write_lock_irqsave(lock, flags)	\
+	do { save_flags(flags); cli(); } while (0)
+#define write_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 }
+
+#define spin_unlock(lock)	((lock)->lock = 0)
+
+static inline void spin_lock(spinlock_t * lock)
+{
+	int stuck = 10000000;
+	int tmp, val;
+	__label__ l1;
+
+l1:	__asm__ __volatile__(
+		"	mtctr %2\n"
+		"1:	lwarx %0,0,%3\n"
+		"	andi. %1,%0,1\n\t"
+		"	ori %0,%0,1\n\t"
+		"	bne- 2f\n\t"
+		"	stwcx. %0,0,%3\n\t"
+		"2:	bdnzf- 2,1b"
+		: "=r" (tmp), "=r" (val)
+		: "r" (stuck), "r" (lock)
+		: "ctr");
+	if (!val) {
+		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 */