md spinlock

9 files changed, 76 insertions, 41 deletions

diff --git a/lib/libpthread/arch/alpha/_atomic_lock.c b/lib/libpthread/arch/alpha/_atomic_lock.c
index b12bc32d94a..75aace9532c 100644
--- a/lib/libpthread/arch/alpha/_atomic_lock.c
+++ b/lib/libpthread/arch/alpha/_atomic_lock.c
@@ -1,42 +1,42 @@
-/*	$OpenBSD: _atomic_lock.c,v 1.2 1998/12/18 05:59:17 d Exp $	*/
+/*	$OpenBSD: _atomic_lock.c,v 1.3 1998/12/21 07:36:59 d Exp $	*/
 /*
  * Atomic lock for alpha
  */
 
 #include "spinlock.h"
 
-register_t
-_atomic_lock(volatile register_t * lock)
+int
+_atomic_lock(volatile _spinlock_lock_t * lock)
 {
-	register_t old;
-	register_t new;
+	_spinlock_lock_t old;
+	_spinlock_lock_t new;
 	int success;
 
 	do {
 		/* load the value of the thread-lock (lock mem on load) */
 		__asm__( "ldq_l %0, %1" : "=r"(old) : "m"(*lock) );
 		if (old) 
-			new = old;	/* in-use: put it back */
+			new = old;	/* locked: no change */
 		else
-			new = 1;	/* free: store a 1 in the lock */
+			new = _SPINLOCK_LOCKED;	/* unlocked: grab it */
 
 		success = 0;
 		/* store the new value of the thrd-lock (unlock mem on store) */
 		/*
 		 * XXX may need to add large branch forward for main line
-		 * branch prediction to be right :(
+		 * branch prediction to be right :( [note from linux]
 		 */
 		__asm__( "stq_c %2, %0; beq %2, 1f; mov 1,%1; 1:"
 					: "=m"(*lock), "=r"(success)
 					: "r"(new) );
 	} while (!success);
 
-	return old;
+	return (old != _SPINLOCK_UNLOCKED);
 }
 
 int
 _atomic_is_locked(volatile register_t * lock)
 {
 	
-	return *lock;
+	return (*lock != _SPINLOCK_UNLOCKED);
 }
diff --git a/lib/libpthread/arch/alpha/_spinlock.h b/lib/libpthread/arch/alpha/_spinlock.h
new file mode 100644
index 00000000000..259260c28a0
--- /dev/null
+++ b/lib/libpthread/arch/alpha/_spinlock.h
@@ -0,0 +1,6 @@
+/*	$OpenBSD: _spinlock.h,v 1.1 1998/12/21 07:36:59 d Exp $	*/
+
+#define _SPINLOCK_UNLOCKED	(0)
+#define _SPINLOCK_LOCKED	(1)
+typedef int _spinlock_lock_t;
+
diff --git a/lib/libpthread/arch/m68k/_atomic_lock.c b/lib/libpthread/arch/m68k/_atomic_lock.c
index d0e2ddbe2d6..9a59370c375 100644
--- a/lib/libpthread/arch/m68k/_atomic_lock.c
+++ b/lib/libpthread/arch/m68k/_atomic_lock.c
@@ -1,14 +1,14 @@
-/*	$OpenBSD: _atomic_lock.c,v 1.2 1998/12/18 05:59:17 d Exp $	*/
+/*	$OpenBSD: _atomic_lock.c,v 1.3 1998/12/21 07:36:59 d Exp $	*/
 /*
  * Atomic lock for m68k
  */
 
 #include "spinlock.h"
 
-register_t
-_atomic_lock(volatile register_t *lock)
+int
+_atomic_lock(volatile _spinlock_lock_t *lock)
 {
-	register_t old;
+	_spinlock_lock_t old;
 
 	/*
 	 * The Compare And Swap instruction (mc68020 and above)
@@ -19,17 +19,17 @@ _atomic_lock(volatile register_t *lock)
 	 *
 	 *      old = 0;
 	 *	CAS(old, 1, *lock);
-	 *	return old;
+	 *	if (old == 1) { lock was acquired }
 	 */
-	old = 0;
+	old = _SPINLOCK_UNLOCKED;
 	__asm__("casl %0, %2, %1" : "=d"(old), "=m"(*lock)
-				  : "d"(1), "0"(old));
-	return old;
+				  : "d"(_SPINLOCK_LOCKED), "0"(old));
+	return (old != _SPINLOCK_UNLOCKED);
 }
 
 int
-_atomic_lock(volatile register_t *lock)
+_atomic_lock(volatile _spinlock_lock_t *lock)
 {
 
-	return *lock;
+	return (*lock != _SPINLOCK_UNLOCKED);
 }
diff --git a/lib/libpthread/arch/m68k/_spinlock.h b/lib/libpthread/arch/m68k/_spinlock.h
new file mode 100644
index 00000000000..06f9ffeb540
--- /dev/null
+++ b/lib/libpthread/arch/m68k/_spinlock.h
@@ -0,0 +1,6 @@
+/*	$OpenBSD: _spinlock.h,v 1.1 1998/12/21 07:37:00 d Exp $	*/
+
+#define _SPINLOCK_UNLOCKED	(0)
+#define _SPINLOCK_LOCKED	(1)
+typedef int _spinlock_lock_t;
+
diff --git a/lib/libpthread/arch/mips/_atomic_lock.c b/lib/libpthread/arch/mips/_atomic_lock.c
index 4df2a99ad85..6961a679069 100644
--- a/lib/libpthread/arch/mips/_atomic_lock.c
+++ b/lib/libpthread/arch/mips/_atomic_lock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: _atomic_lock.c,v 1.2 1998/12/18 05:59:18 d Exp $	*/
+/*	$OpenBSD: _atomic_lock.c,v 1.3 1998/12/21 07:37:00 d Exp $	*/
 /*
  * Atomic lock for mips
  */
@@ -12,12 +12,12 @@
  * 	attempt to acquire a lock (by giving it a non-zero value).
  *	Return zero on success, or the lock's value on failure
  */
-register_t
-_atomic_lock(volatile register_t *lock)
+int
+_atomic_lock(volatile _spinlock_lock_t *lock)
 {
-	register_t old;
 #if __mips >= 2
-	register_t temp;
+	_spinlock_lock_t old;
+	_spinlock_lock_t temp;
 
 	do {
 		/*
@@ -27,7 +27,7 @@ _atomic_lock(volatile register_t *lock)
 		 * physical address of lock for diagnostic purposes);
 		 */
 		__asm__("ll %0, %1" : "=r"(old) : "m"(*lock));
-		if (old) 
+		if (old != _SPINLOCK_UNLOCKED) 
 			break; /* already locked */
 		/*
 		 * Try and store a 1 at the tagged lock address.  If
@@ -35,25 +35,29 @@ _atomic_lock(volatile register_t *lock)
 		 * line will have been wiped, and temp will be set to zero
 		 * by the 'store conditional' instruction.
 		 */
-		temp = 1;
+		temp = _SPINLOCK_LOCKED;
 		__asm__("sc  %0, %1" : "=r"(temp), "=m"(*lock)
 				     : "0"(temp));
 	} while (temp == 0);
+
+	return (old != _SPINLOCK_UNLOCKED);
 #else
 	/*
 	 * Older MIPS cpus have no way of doing an atomic lock
 	 * without some kind of shift to supervisor mode.
 	 */
 
-	old = _thread_slow_atomic_lock(lock);
-
+	return (_thread_slow_atomic_lock(lock));
 #endif
-	return old;
 }
 
 int
-_atomic_is_locked(volatile register_t * lock)
+_atomic_is_locked(volatile register_t *lock)
 {
 	
-	return *lock;
+#if __mips >= 2
+	return (*lock != _SPINLOCK_UNLOCKED);
+#else
+	return (_thread_slow_atomic_is_locked(lock));
+#endif
 }
diff --git a/lib/libpthread/arch/mips/_spinlock.h b/lib/libpthread/arch/mips/_spinlock.h
new file mode 100644
index 00000000000..06f9ffeb540
--- /dev/null
+++ b/lib/libpthread/arch/mips/_spinlock.h
@@ -0,0 +1,6 @@
+/*	$OpenBSD: _spinlock.h,v 1.1 1998/12/21 07:37:00 d Exp $	*/
+
+#define _SPINLOCK_UNLOCKED	(0)
+#define _SPINLOCK_LOCKED	(1)
+typedef int _spinlock_lock_t;
+
diff --git a/lib/libpthread/arch/sparc/_atomic_lock.c b/lib/libpthread/arch/sparc/_atomic_lock.c
index 530c86b4805..31636328f93 100644
--- a/lib/libpthread/arch/sparc/_atomic_lock.c
+++ b/lib/libpthread/arch/sparc/_atomic_lock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: _atomic_lock.c,v 1.2 1998/12/18 05:59:18 d Exp $	*/
+/*	$OpenBSD: _atomic_lock.c,v 1.3 1998/12/21 07:37:01 d Exp $	*/
 /*
  * Atomic lock for sparc
  */
@@ -15,5 +15,5 @@ int
 _atomic_is_locked(volatile register_t * lock)
 {
 	
-	return *lock;
+	return _thread_slow_atomic_is_locked(lock);
 }
diff --git a/lib/libpthread/arch/sparc/_spinlock.h b/lib/libpthread/arch/sparc/_spinlock.h
new file mode 100644
index 00000000000..87b8e5485e3
--- /dev/null
+++ b/lib/libpthread/arch/sparc/_spinlock.h
@@ -0,0 +1,6 @@
+/*	$OpenBSD: _spinlock.h,v 1.1 1998/12/21 07:37:01 d Exp $	*/
+
+#define _SPINLOCK_UNLOCKED	(0)
+#define _SPINLOCK_LOCKED	(1)
+typedef int _spinlock_lock_t;
+
diff --git a/lib/libpthread/sys/slow_atomic_lock.c b/lib/libpthread/sys/slow_atomic_lock.c
index ca86bb3dd52..22889ea8691 100644
--- a/lib/libpthread/sys/slow_atomic_lock.c
+++ b/lib/libpthread/sys/slow_atomic_lock.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: slow_atomic_lock.c,v 1.2 1998/11/21 14:02:10 d Exp $	*/
+/*	$OpenBSD: slow_atomic_lock.c,v 1.3 1998/12/21 07:38:43 d Exp $	*/
 
 #include <pthread.h>
 #include "pthread_private.h"
@@ -12,10 +12,10 @@
  *	This uses signal masking to make sure that no other thread
  *	can modify the lock while processing, hence it is very slow.
  */
-register_t
-_thread_slow_atomic_lock(volatile register_t *lock)
+int
+_thread_slow_atomic_lock(volatile _spinlock_lock_t *lock)
 {
-	register_t old;
+	_spinlock_lock_t old;
 	sigset_t oldset, newset = (sigset_t)~0;
 
 	/* block signals - incurs a context switch */
@@ -23,12 +23,19 @@ _thread_slow_atomic_lock(volatile register_t *lock)
 		PANIC("_atomic_lock block");
 
 	old = *lock;
-	if (old == 0)
-		*lock = 1;
+	if (old == _SPINLOCK_UNLOCKED)
+		*lock = _SPINLOCK_LOCKED;
 
 	/* restore signal mask to what it was */
 	if (_thread_sys_sigprocmask(SIG_SETMASK, &oldset, NULL) < 0)
 		PANIC("_atomic_lock restore");
 
-	return old;
+	return (old != _SPINLOCK_UNLOCKED);
+}
+
+int
+_thread_slow_atomic_is_locked(volatile _spinlock_lock_t *lock)
+{
+
+	return (*lock != _SPINLOCK_UNLOCKED);
 }