[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>

[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>
Segher Boessenkool · Paul Mackerras
1 parent c6d4267ece
Showing 1 changed file with 28 additions and 6 deletions Side-by-side Diff
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>
  
@@ -15,9 +15,20 @@
  
 #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)
 {
 	int t;
  
@@ -240,12 +251,23 @@
  
 #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)
 {
...	...	@@ -5,7 +5,7 @@
5	5	* PowerPC atomic operations
6	6	*/
7	7
8		-typedef struct { volatile int counter; } atomic_t;
	8	+typedef struct { int counter; } atomic_t;
9	9
10	10	#ifdef __KERNEL__
11	11	#include <linux/compiler.h>
12	12
...	...	@@ -15,9 +15,20 @@
15	15
16	16	#define ATOMIC_INIT(i) { (i) }
17	17
18		-#define atomic_read(v) ((v)->counter)
19		-#define atomic_set(v,i) (((v)->counter) = (i))
	18	+static __inline__ int atomic_read(const atomic_t *v)
	19	+{
	20	+ int t;
20	21
	22	+ __asm__ __volatile__("lwz%U1%X1 %0,%1" : "=r"(t) : "m"(v->counter));
	23	+
	24	+ return t;
	25	+}
	26	+
	27	+static __inline__ void atomic_set(atomic_t *v, int i)
	28	+{
	29	+ __asm__ __volatile__("stw%U0%X0 %1,%0" : "=m"(v->counter) : "r"(i));
	30	+}
	31	+
21	32	static __inline__ void atomic_add(int a, atomic_t *v)
22	33	{
23	34	int t;
24	35
...	...	@@ -240,12 +251,23 @@
240	251
241	252	#ifdef __powerpc64__
242	253
243		-typedef struct { volatile long counter; } atomic64_t;
	254	+typedef struct { long counter; } atomic64_t;
244	255
245	256	#define ATOMIC64_INIT(i) { (i) }
246	257
247		-#define atomic64_read(v) ((v)->counter)
248		-#define atomic64_set(v,i) (((v)->counter) = (i))
	258	+static __inline__ long atomic64_read(const atomic64_t *v)
	259	+{
	260	+ long t;
	261	+
	262	+ __asm__ __volatile__("ld%U1%X1 %0,%1" : "=r"(t) : "m"(v->counter));
	263	+
	264	+ return t;
	265	+}
	266	+
	267	+static __inline__ void atomic64_set(atomic64_t *v, long i)
	268	+{
	269	+ __asm__ __volatile__("std%U0%X0 %1,%0" : "=m"(v->counter) : "r"(i));
	270	+}
249	271
250	272	static __inline__ void atomic64_add(long a, atomic64_t *v)
251	273	{