powerpc: Rename LWSYNC_ON_SMP to PPC_RELEASE_BARRIER, ISYNC_ON_SMP to PPC_ACQUIRE_BARRIER

For performance reasons we are about to change ISYNC_ON_SMP to sometimes be
lwsync. Now that the macro name doesn't make sense, change it and LWSYNC_ON_SMP
to better explain what the barriers are doing.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/system.h b/arch/powerpc/include/asm/system.h
index bb8e006..aa59f5b 100644
--- a/arch/powerpc/include/asm/system.h
+++ b/arch/powerpc/include/asm/system.h
@@ -232,12 +232,12 @@
 	unsigned long prev;
 
 	__asm__ __volatile__(
-	LWSYNC_ON_SMP
+	PPC_RELEASE_BARRIER
 "1:	lwarx	%0,0,%2 \n"
 	PPC405_ERR77(0,%2)
 "	stwcx.	%3,0,%2 \n\
 	bne-	1b"
-	ISYNC_ON_SMP
+	PPC_ACQUIRE_BARRIER
 	: "=&r" (prev), "+m" (*(volatile unsigned int *)p)
 	: "r" (p), "r" (val)
 	: "cc", "memory");
@@ -275,12 +275,12 @@
 	unsigned long prev;
 
 	__asm__ __volatile__(
-	LWSYNC_ON_SMP
+	PPC_RELEASE_BARRIER
 "1:	ldarx	%0,0,%2 \n"
 	PPC405_ERR77(0,%2)
 "	stdcx.	%3,0,%2 \n\
 	bne-	1b"
-	ISYNC_ON_SMP
+	PPC_ACQUIRE_BARRIER
 	: "=&r" (prev), "+m" (*(volatile unsigned long *)p)
 	: "r" (p), "r" (val)
 	: "cc", "memory");
@@ -366,14 +366,14 @@
 	unsigned int prev;
 
 	__asm__ __volatile__ (
-	LWSYNC_ON_SMP
+	PPC_RELEASE_BARRIER
 "1:	lwarx	%0,0,%2		# __cmpxchg_u32\n\
 	cmpw	0,%0,%3\n\
 	bne-	2f\n"
 	PPC405_ERR77(0,%2)
 "	stwcx.	%4,0,%2\n\
 	bne-	1b"
-	ISYNC_ON_SMP
+	PPC_ACQUIRE_BARRIER
 	"\n\
 2:"
 	: "=&r" (prev), "+m" (*p)
@@ -412,13 +412,13 @@
 	unsigned long prev;
 
 	__asm__ __volatile__ (
-	LWSYNC_ON_SMP
+	PPC_RELEASE_BARRIER
 "1:	ldarx	%0,0,%2		# __cmpxchg_u64\n\
 	cmpd	0,%0,%3\n\
 	bne-	2f\n\
 	stdcx.	%4,0,%2\n\
 	bne-	1b"
-	ISYNC_ON_SMP
+	PPC_ACQUIRE_BARRIER
 	"\n\
 2:"
 	: "=&r" (prev), "+m" (*p)