arm64: lib: use pair accessors for copy_*_user routines
The AArch64 instruction set contains load/store pair memory accessors,
so use these in our copy_*_user routines to transfer 16 bytes per
iteration.
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
diff --git a/arch/arm64/lib/copy_from_user.S b/arch/arm64/lib/copy_from_user.S
index 5e27add..47c3fa5 100644
--- a/arch/arm64/lib/copy_from_user.S
+++ b/arch/arm64/lib/copy_from_user.S
@@ -28,14 +28,19 @@
* x0 - bytes not copied
*/
ENTRY(__copy_from_user)
- add x4, x1, x2 // upper user buffer boundary
- subs x2, x2, #8
+ add x5, x1, x2 // upper user buffer boundary
+ subs x2, x2, #16
+ b.mi 1f
+0:
+USER(9f, ldp x3, x4, [x1], #16)
+ subs x2, x2, #16
+ stp x3, x4, [x0], #16
+ b.pl 0b
+1: adds x2, x2, #8
b.mi 2f
-1:
USER(9f, ldr x3, [x1], #8 )
- subs x2, x2, #8
+ sub x2, x2, #8
str x3, [x0], #8
- b.pl 1b
2: adds x2, x2, #4
b.mi 3f
USER(9f, ldr w3, [x1], #4 )
@@ -56,7 +61,7 @@
.section .fixup,"ax"
.align 2
-9: sub x2, x4, x1
+9: sub x2, x5, x1
mov x3, x2
10: strb wzr, [x0], #1 // zero remaining buffer space
subs x3, x3, #1