From 04d13b5d09c17a076260e2b9fb92c0d708d37264 Mon Sep 17 00:00:00 2001 From: "Edgar E. Iglesias" Date: Wed, 9 Sep 2020 19:07:25 +0200 Subject: [PATCH] arm64: Trap PIE builds early if load address is not 4K aligned MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit PIE requires a 4K aligned load address. If this is not met, trap the startup sequence in a WFI loop rather than running into obscure failures. Tested-by: Michal Simek Suggested-by: André Przywara Signed-off-by: Edgar E. Iglesias Reviewed-by: Stephen Warren Signed-off-by: Michal Simek --- arch/arm/cpu/armv8/start.S | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S index 002698b501..85baebc5f7 100644 --- a/arch/arm/cpu/armv8/start.S +++ b/arch/arm/cpu/armv8/start.S @@ -59,6 +59,23 @@ reset: save_boot_params_ret: #if CONFIG_POSITION_INDEPENDENT + /* Verify that we're 4K aligned. */ + adr x0, _start + ands x0, x0, #0xfff + b.eq 1f +0: + /* + * FATAL, can't continue. + * U-Boot needs to be loaded at a 4K aligned address. + * + * We use ADRP and ADD to load some symbol addresses during startup. + * The ADD uses an absolute (non pc-relative) lo12 relocation + * thus requiring 4K alignment. + */ + wfi + b 0b +1: + /* * Fix .rela.dyn relocations. This allows U-Boot to be loaded to and * executed at a different address than it was linked at. -- 2.39.5