arm64: PIE: Skip fixups if distance is zero
When the actual offset between link and runtime address is zero, there
is no need for patching up U-Boot early when running with
CONFIG_POSITION_INDEPENDENT.
Skip the whole routine when the distance is 0.
This helps when U-Boot is loaded into ROM, or in otherwise sensitive
memory locations.
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S
index e5c2856..6624491 100644
--- a/arch/arm/cpu/armv8/start.S
+++ b/arch/arm/cpu/armv8/start.S
@@ -83,7 +83,8 @@
pie_fixup:
adr x0, _start /* x0 <- Runtime value of _start */
ldr x1, _TEXT_BASE /* x1 <- Linked value of _start */
- sub x9, x0, x1 /* x9 <- Run-vs-link offset */
+ subs x9, x0, x1 /* x9 <- Run-vs-link offset */
+ beq pie_fixup_done
adrp x2, __rel_dyn_start /* x2 <- Runtime &__rel_dyn_start */
add x2, x2, #:lo12:__rel_dyn_start
adrp x3, __rel_dyn_end /* x3 <- Runtime &__rel_dyn_end */