From: Russell King <rmk@dyn-67.arm.linux.org.uk>
Date: Sun, 24 Jul 2005 11:13:40 +0000 (+0100)
Subject: [PATCH] ARM SMP: Fix ARMv6 spinlock and semaphore implementations
X-Git-Tag: v2.6.13-rc4~78
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4e8fd22bd421d7aa279bcb76189505a1f96bb7bf;p=linux-2.6

[PATCH] ARM SMP: Fix ARMv6 spinlock and semaphore implementations

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---

diff --git a/include/asm-arm/locks.h b/include/asm-arm/locks.h
index c26298f389..9cb33fcc06 100644
--- a/include/asm-arm/locks.h
+++ b/include/asm-arm/locks.h
@@ -61,7 +61,7 @@
 "	strex	ip, lr, [%0]\n"			\
 "	teq	ip, #0\n"			\
 "	bne	1b\n"				\
-"	teq	lr, #0\n"			\
+"	cmp	lr, #0\n"			\
 "	movle	ip, %0\n"			\
 "	blle	" #wake				\
 	:					\
@@ -100,7 +100,7 @@
 	__asm__ __volatile__(			\
 	"@ up_op_read\n"			\
 "1:	ldrex	lr, [%0]\n"			\
-"	add	lr, lr, %1\n"			\
+"	adds	lr, lr, %1\n"			\
 "	strex	ip, lr, [%0]\n"			\
 "	teq	ip, #0\n"			\
 "	bne	1b\n"				\
diff --git a/include/asm-arm/spinlock.h b/include/asm-arm/spinlock.h
index 182323619c..9705d5eec9 100644
--- a/include/asm-arm/spinlock.h
+++ b/include/asm-arm/spinlock.h
@@ -79,7 +79,8 @@ typedef struct {
 } rwlock_t;
 
 #define RW_LOCK_UNLOCKED	(rwlock_t) { 0 }
-#define rwlock_init(x)		do { *(x) + RW_LOCK_UNLOCKED; } while (0)
+#define rwlock_init(x)		do { *(x) = RW_LOCK_UNLOCKED; } while (0)
+#define rwlock_is_locked(x)	(*((volatile unsigned int *)(x)) != 0)
 
 /*
  * Write locks are easy - we just set bit 31.  When unlocking, we can
@@ -100,6 +101,21 @@ static inline void _raw_write_lock(rwlock_t *rw)
 	: "cc", "memory");
 }
 
+static inline int _raw_write_trylock(rwlock_t *rw)
+{
+	unsigned long tmp;
+
+	__asm__ __volatile__(
+"1:	ldrex	%0, [%1]\n"
+"	teq	%0, #0\n"
+"	strexeq	%0, %2, [%1]"
+	: "=&r" (tmp)
+	: "r" (&rw->lock), "r" (0x80000000)
+	: "cc", "memory");
+
+	return tmp == 0;
+}
+
 static inline void _raw_write_unlock(rwlock_t *rw)
 {
 	__asm__ __volatile__(
@@ -138,6 +154,8 @@ static inline void _raw_read_lock(rwlock_t *rw)
 
 static inline void _raw_read_unlock(rwlock_t *rw)
 {
+	unsigned long tmp, tmp2;
+
 	__asm__ __volatile__(
 "1:	ldrex	%0, [%2]\n"
 "	sub	%0, %0, #1\n"
@@ -151,19 +169,4 @@ static inline void _raw_read_unlock(rwlock_t *rw)
 
 #define _raw_read_trylock(lock) generic_raw_read_trylock(lock)
 
-static inline int _raw_write_trylock(rwlock_t *rw)
-{
-	unsigned long tmp;
-
-	__asm__ __volatile__(
-"1:	ldrex	%0, [%1]\n"
-"	teq	%0, #0\n"
-"	strexeq	%0, %2, [%1]"
-	: "=&r" (tmp)
-	: "r" (&rw->lock), "r" (0x80000000)
-	: "cc", "memory");
-
-	return tmp == 0;
-}
-
 #endif /* __ASM_SPINLOCK_H */