patch-2.2.11 linux/include/asm-mips/semaphore.h

• Lines: 116
• Date: Mon Aug 9 12:04:41 1999
• Orig file: v2.2.10/linux/include/asm-mips/semaphore.h
• Orig date: Thu Jan 14 15:53:25 1999

diff -u --recursive --new-file v2.2.10/linux/include/asm-mips/semaphore.h linux/include/asm-mips/semaphore.h
@@ -1,11 +1,13 @@
-/*
+/* $Id: semaphore.h,v 1.5.2.2 1999/06/17 12:09:42 ralf Exp $
+ *
  * SMP- and interrupt-safe semaphores..
  *
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * (C) Copyright 1996  Linus Torvalds, Ralf Baechle
+ * (C) Copyright 1996  Linus Torvalds
+ * (C) Copyright 1998, 1999  Ralf Baechle
  */
 #ifndef __ASM_MIPS_SEMAPHORE_H
 #define __ASM_MIPS_SEMAPHORE_H
@@ -23,44 +25,15 @@
 #define MUTEX ((struct semaphore) { ATOMIC_INIT(1), ATOMIC_INIT(0), NULL })
 #define MUTEX_LOCKED ((struct semaphore) { ATOMIC_INIT(0), ATOMIC_INIT(0), NULL })
 
-extern void __down(struct semaphore * sem);
-extern int  __down_interruptible(struct semaphore * sem);
-extern void __up(struct semaphore * sem);
+asmlinkage void __down(struct semaphore * sem);
+asmlinkage int  __down_interruptible(struct semaphore * sem);
+asmlinkage int __down_trylock(struct semaphore * sem);
+asmlinkage void __up(struct semaphore * sem);
 
 extern spinlock_t semaphore_wake_lock;
 
 #define sema_init(sem, val)	atomic_set(&((sem)->count), val)
 
-/*
- * These two _must_ execute atomically wrt each other.
- *
- * This is trivially done with load_locked/store_cond,
- * which we have.  Let the rest of the losers suck eggs.
- */
-
-static inline void wake_one_more(struct semaphore * sem)
-{
-	atomic_inc(&sem->waking);
-}
-
-static inline int waking_non_zero(struct semaphore *sem, struct task_struct *tsk)
-{
-	int ret, tmp;
-
-	__asm__ __volatile__(
-	"1:\tll\t%1,%2\n"
-	"blez\t%1,2f\n\t"
-	"subu\t%0,%1,1\n\t"
-	"sc\t%0,%2\n\t"
-	"beqz\t%0,1b\n\t"
-	"2:"
-	".text"
-	: "=r"(ret), "=r"(tmp), "=m"(__atomic_fool_gcc(&sem->waking))
-	: "0"(0));
-
-	return ret;
-}
-
 extern inline void down(struct semaphore * sem)
 {
 	if (atomic_dec_return(&sem->count) < 0)
@@ -72,6 +45,50 @@
 	int ret = 0;
 	if (atomic_dec_return(&sem->count) < 0)
 		ret = __down_interruptible(sem);
+	return ret;
+}
+
+/*
+ * down_trylock returns 0 on success, 1 if we failed to get the lock.
+ *
+ * We must manipulate count and waking simultaneously and atomically.
+ * Do this by using ll/sc on the pair of 32-bit words.
+ */
+extern inline int down_trylock(struct semaphore * sem)
+{
+	long ret, tmp, tmp2, sub;
+
+#ifdef __MIPSEB__
+	__asm__ __volatile__("
+			.set	mips3
+		0:	lld	%1, %4
+			dli	%3, 0x0000000100000000
+			sltu	%0, %1, $0
+
+			bltz	%1, 1f
+			move	%3, $0
+		1:
+
+			sltu	%2, %1, $0
+			and	%0, %0, %2
+			bnez	%0, 2f
+
+			subu	%0, %3
+			scd	%1, %4
+
+			beqz	%1, 0b
+		2:
+
+			.set	mips0"
+		: "=&r"(ret), "=&r"(tmp), "=&r"(tmp2), "=&r"(sub)
+		: "m"(*sem)
+		: "memory");
+#endif
+
+#ifdef __MIPSEL__
+#error "FIXME: down_trylock doesn't support little endian machines yet."
+#endif
+
 	return ret;
 }