Import of Linux/MIPS 2.1.14

1 files changed, 70 insertions, 0 deletions

diff --git a/include/asm-i386/semaphore.h b/include/asm-i386/semaphore.h
new file mode 100644
index 000000000..930b39edb
--- /dev/null
+++ b/include/asm-i386/semaphore.h
@@ -0,0 +1,70 @@
+#ifndef _I386_SEMAPHORE_H
+#define _I386_SEMAPHORE_H
+
+#include <linux/linkage.h>
+
+/*
+ * SMP- and interrupt-safe semaphores..
+ *
+ * (C) Copyright 1996 Linus Torvalds
+ */
+
+struct semaphore {
+	int count;
+	int waiting;
+	struct wait_queue * wait;
+};
+
+#define MUTEX ((struct semaphore) { 1, 0, NULL })
+#define MUTEX_LOCKED ((struct semaphore) { 0, 0, NULL })
+
+asmlinkage void __down_failed(void /* special register calling convention */);
+asmlinkage void __up_wakeup(void /* special register calling convention */);
+
+extern void __down(struct semaphore * sem);
+extern void __up(struct semaphore * sem);
+
+/*
+ * This is ugly, but we want the default case to fall through.
+ * "down_failed" is a special asm handler that calls the C
+ * routine that actually waits. See arch/i386/lib/semaphore.S
+ */
+extern __inline__ void down(struct semaphore * sem)
+{
+	__asm__ __volatile__(
+		"# atomic down operation\n\t"
+#ifdef __SMP__
+		"lock ; "
+#endif
+		"decl %0\n\t"
+		"movl $1f,%%eax\n\t"
+		"js " SYMBOL_NAME_STR(__down_failed)
+		"\n1:"
+		:/* no outputs */
+		:"m" (sem->count), "c" (sem)
+		:"ax", "memory");
+}
+
+/*
+ * Note! This is subtle. We jump to wake people up only if
+ * the semaphore was negative (== somebody was waiting on it).
+ * The default case (no contention) will result in NO
+ * jumps for both down() and up().
+ */
+extern __inline__ void up(struct semaphore * sem)
+{
+	__asm__ __volatile__(
+		"# atomic up operation\n\t"
+#ifdef __SMP__
+		"lock ; "
+#endif
+		"incl %0\n\t"
+		"movl $1f,%%eax\n\t"
+		"jle " SYMBOL_NAME_STR(__up_wakeup)
+		"\n1:"
+		:/* no outputs */
+		:"m" (sem->count), "c" (sem)
+		:"ax", "memory");
+}
+
+#endif