From 9a984f100ed1d2d4a3aed7db9cfd1a3892e2bccd Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Wed, 30 Sep 2020 17:39:14 +0100 Subject: [PATCH] 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 Reviewed-by: Stephen Warren --- arch/arm/cpu/armv8/start.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S index e5c2856cf5..662449156b 100644 --- a/arch/arm/cpu/armv8/start.S +++ b/arch/arm/cpu/armv8/start.S @@ -83,7 +83,8 @@ 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 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 */ -- 2.39.5