From: Segher Boessenkool <segher@kernel.crashing.org>
Date: Sat, 11 Aug 2007 00:15:30 +0000 (+1000)
Subject: [POWERPC] Implement atomic{, 64}_{read, write}() without volatile
X-Git-Tag: upstream/snapshot3+hdmi~30754^2~350
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=9f0cbea0d8cc47801b853d3c61d0e17475b0cc89;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git

[POWERPC] Implement atomic{, 64}_{read, write}() without volatile

Instead, use asm() like all other atomic operations already do.

Also use inline functions instead of macros; this actually
improves code generation (some code becomes a little smaller,
probably because of improved alias information -- just a few
hundred bytes total on a default kernel build, nothing shocking).

Signed-off-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
---

diff --git a/include/asm-powerpc/atomic.h b/include/asm-powerpc/atomic.h
index c44810b..f3fc733 100644
--- a/include/asm-powerpc/atomic.h
+++ b/include/asm-powerpc/atomic.h
@@ -5,7 +5,7 @@
  * PowerPC atomic operations
  */
 
-typedef struct { volatile int counter; } atomic_t;
+typedef struct { int counter; } atomic_t;
 
 #ifdef __KERNEL__
 #include <linux/compiler.h>
@@ -15,8 +15,19 @@ typedef struct { volatile int counter; } atomic_t;
 
 #define ATOMIC_INIT(i)		{ (i) }
 
-#define atomic_read(v)		((v)->counter)
-#define atomic_set(v,i)		(((v)->counter) = (i))
+static __inline__ int atomic_read(const atomic_t *v)
+{
+	int t;
+
+	__asm__ __volatile__("lwz%U1%X1 %0,%1" : "=r"(t) : "m"(v->counter));
+
+	return t;
+}
+
+static __inline__ void atomic_set(atomic_t *v, int i)
+{
+	__asm__ __volatile__("stw%U0%X0 %1,%0" : "=m"(v->counter) : "r"(i));
+}
 
 static __inline__ void atomic_add(int a, atomic_t *v)
 {
@@ -240,12 +251,23 @@ static __inline__ int atomic_dec_if_positive(atomic_t *v)
 
 #ifdef __powerpc64__
 
-typedef struct { volatile long counter; } atomic64_t;
+typedef struct { long counter; } atomic64_t;
 
 #define ATOMIC64_INIT(i)	{ (i) }
 
-#define atomic64_read(v)	((v)->counter)
-#define atomic64_set(v,i)	(((v)->counter) = (i))
+static __inline__ long atomic64_read(const atomic64_t *v)
+{
+	long t;
+
+	__asm__ __volatile__("ld%U1%X1 %0,%1" : "=r"(t) : "m"(v->counter));
+
+	return t;
+}
+
+static __inline__ void atomic64_set(atomic64_t *v, long i)
+{
+	__asm__ __volatile__("std%U0%X0 %1,%0" : "=m"(v->counter) : "r"(i));
+}
 
 static __inline__ void atomic64_add(long a, atomic64_t *v)
 {