[ARM] cache align destination pointer when copying memory for some processors
The implementation for memory copy functions on ARM had a (disabled)
provision for aligning the source pointer before loading registers with
data. Turns out that aligning the _destination_ pointer is much more
useful, as the read side is already sufficiently helped with the use of
preload.
So this changes the definition of the CALGN() macro to target the
destination pointer instead, and turns it on for Feroceon processors
where the gain is very noticeable.
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Lennert Buytenhek <buytenh@marvell.com>
diff --git a/arch/arm/lib/memmove.S b/arch/arm/lib/memmove.S
index 018522c..2e301b7 100644
--- a/arch/arm/lib/memmove.S
+++ b/arch/arm/lib/memmove.S
@@ -13,14 +13,6 @@
#include <linux/linkage.h>
#include <asm/assembler.h>
-/*
- * This can be used to enable code to cacheline align the source pointer.
- * Experiments on tested architectures (StrongARM and XScale) didn't show
- * this a worthwhile thing to do. That might be different in the future.
- */
-//#define CALGN(code...) code
-#define CALGN(code...)
-
.text
/*
@@ -55,7 +47,7 @@
stmfd sp!, {r5 - r8}
blt 5f
- CALGN( ands ip, r1, #31 )
+ CALGN( ands ip, r0, #31 )
CALGN( sbcnes r4, ip, r2 ) @ C is always set here
CALGN( bcs 2f )
CALGN( adr r4, 6f )
@@ -139,7 +131,7 @@
subs r2, r2, #28
blt 14f
- CALGN( ands ip, r1, #31 )
+ CALGN( ands ip, r0, #31 )
CALGN( sbcnes r4, ip, r2 ) @ C is always set here
CALGN( subcc r2, r2, ip )
CALGN( bcc 15f )