---

yaml --- r: 155220 b: refs/heads/master c: a79f0da h: refs/heads/master v: v3
git-mirror · Jul 4, 2009 · f238fcf · f238fcf
1 parent 3e47ef3
commit f238fcf
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Showing 3 changed files with 24 additions and 23 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: ddf9a003d32f720805ac30bcc15755e9289073de
+refs/heads/master: a79f0da80a508448434476b77f9d3d1a469eab67
diff --git a/trunk/arch/x86/include/asm/atomic_32.h b/trunk/arch/x86/include/asm/atomic_32.h
@@ -295,6 +295,28 @@ extern void atomic64_set(atomic64_t *ptr, u64 new_val);
  *
  * Atomically reads the value of @ptr and returns it.
  */
+static inline u64 atomic64_read(atomic64_t *ptr)
+{
+	u64 res;
+
+	/*
+	 * Note, we inline this atomic64_t primitive because
+	 * it only clobbers EAX/EDX and leaves the others
+	 * untouched. We also (somewhat subtly) rely on the
+	 * fact that cmpxchg8b returns the current 64-bit value
+	 * of the memory location we are touching:
+	 */
+	asm volatile(
+		"mov %%ebx, %%eax\n\t"
+		"mov %%ecx, %%edx\n\t"
+		LOCK_PREFIX "cmpxchg8b %1\n"
+			: "=&A" (res)
+			: "m" (*ptr)
+		);
+
+	return res;
+}
+
 extern u64 atomic64_read(atomic64_t *ptr);
 
 /**

diff --git a/trunk/arch/x86/lib/atomic64_32.c b/trunk/arch/x86/lib/atomic64_32.c
@@ -66,31 +66,10 @@ void atomic64_set(atomic64_t *ptr, u64 new_val)
 {
 	atomic64_xchg(ptr, new_val);
 }
-EXPORT_SYMBOL(atomic64_read);
+EXPORT_SYMBOL(atomic64_set);
 
 /**
- * atomic64_read - read atomic64 variable
- * @ptr:      pointer to type atomic64_t
- *
- * Atomically reads the value of @ptr and returns it.
- */
-u64 atomic64_read(atomic64_t *ptr)
-{
-	u64 res;
-
-	asm volatile(
-		"mov %%ebx, %%eax\n\t"
-		"mov %%ecx, %%edx\n\t"
-		LOCK_PREFIX "cmpxchg8b %1\n"
-			: "+A" (res)
-			: "m" (*ptr)
-		);
-
-	return res;
-}
 EXPORT_SYMBOL(atomic64_read);
-
-/**
  * atomic64_add_return - add and return
  * @delta: integer value to add
  * @ptr:   pointer to type atomic64_t