diff mbox series

[v2,2/6] arm64: PIE: Skip fixups if distance is zero

Message ID 20200930163918.24995-3-andre.przywara@arm.com
State Accepted
Delegated to: Tom Rini
Headers show
Series qemu-arm64: Allow booting via Trusted Firmware | expand

Commit Message

André Przywara Sept. 30, 2020, 4:39 p.m. UTC
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>
---
 arch/arm/cpu/armv8/start.S | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Tom Rini Oct. 9, 2020, 1:02 p.m. UTC | #1
On Wed, Sep 30, 2020 at 05:39:14PM +0100, Andre Przywara wrote:

> 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>

Applied to u-boot/master, thanks!
diff mbox series

Patch

diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S
index 002698b501c..02b952bb328 100644
--- a/arch/arm/cpu/armv8/start.S
+++ b/arch/arm/cpu/armv8/start.S
@@ -66,7 +66,8 @@  save_boot_params_ret:
 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
 	adr	x2, __rel_dyn_start	/* x2 <- Runtime &__rel_dyn_start */
 	adr	x3, __rel_dyn_end	/* x3 <- Runtime &__rel_dyn_end */
 pie_fix_loop: