[U-Boot] [PATCH v3 6/6] arm: optimize relocate_code routine

Albert ARIBAUD
2013-06-11T12:17:35Z

Use section symbols directly
Drop support for R_ARM_ABS32 record types
Eliminate unneeded intermediate registers
Optimize relocation table iteration

Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
---
Changes in v3: None
Changes in v2: None

arch/arm/lib/relocate.S | 32 ++++++++++++--------------------
1 file changed, 12 insertions(+), 20 deletions(-)

diff --git a/arch/arm/lib/relocate.S b/arch/arm/lib/relocate.S
index 3f444c1..949b9e8 100644
--- a/arch/arm/lib/relocate.S
+++ b/arch/arm/lib/relocate.S
@@ -37,19 +37,15 @@
*/

ENTRY(relocate_code)
- mov r6, r0 /* save addr of destination */
-
- ldr r0, =__image_copy_start /* r0 <- SRC &__image_copy_start */
- subs r9, r6, r0 /* r9 <- relocation offset */
+ ldr r1, =__image_copy_start /* r1 <- SRC &__image_copy_start */
+ subs r9, r0, r1 /* r9 <- relocation offset */
beq relocate_done /* skip relocation */
- mov r1, r6 /* r1 <- scratch for copy loop */
- adr r7, relocate_code /* r7 <- SRC &relocate_code */
ldr r2, =__image_copy_end /* r2 <- SRC &__image_copy_end */

copy_loop:
- ldmia r0!, {r10-r11} /* copy from source address [r0] */
- stmia r1!, {r10-r11} /* copy to target address [r1] */
- cmp r0, r2 /* until source end address [r2] */
+ ldmia r1!, {r10-r11} /* copy from source address [r1] */
+ stmia r0!, {r10-r11} /* copy to target address [r0] */
+ cmp r1, r2 /* until source end address [r2] */
blo copy_loop

/*
@@ -58,21 +54,17 @@ copy_loop:
ldr r2, =__rel_dyn_start /* r2 <- SRC &__rel_dyn_start */
ldr r3, =__rel_dyn_end /* r3 <- SRC &__rel_dyn_end */
fixloop:
- ldr r0, [r2] /* r0 <- SRC location to fix up */
- add r0, r0, r9 /* r0 <- DST location to fix up */
- ldr r1, [r2, #4]
- and r7, r1, #0xff
- cmp r7, #23 /* relative fixup? */
- beq fixrel
- /* ignore unknown type of fixup */
- b fixnext
-fixrel:
+ ldmia r2!, {r0-r1} /* (r0,r1) <- (SRC location,fixup) */
+ and r1, r1, #0xff
+ cmp r1, #23 /* relative fixup? */
+ bne fixnext
+
/* relative fix: increase location by offset */
+ add r0, r0, r9
ldr r1, [r0]
add r1, r1, r9
-fixnext:
str r1, [r0]
- add r2, r2, #8 /* each rel.dyn entry is 8 bytes */
+fixnext:
cmp r2, r3
blo fixloop

--
1.7.10.4