From 751c263bb74fd36b5fc2589d36abc75042336444 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Mon, 15 Jun 2020 12:19:39 +0200 Subject: [PATCH] arm64: remove TEXT_OFFSET randomization TEXT_OFFSET was recently changed to 0x0, in preparation for its removal at a later stage, and a warning is emitted into the kernel log when the bootloader appears to have failed to take the TEXT_OFFSET image header value into account. Ironically, this warning itself fails to take TEXT_OFFSET into account, and compares the kernel image's alignment modulo 2M against a hardcoded value of 0x0, and so the warning will trigger spuriously when TEXT_OFFSET randomization is enabled. Given the intent to get rid of TEXT_OFFSET entirely, let's fix this oversight by just removing support for TEXT_OFFSET randomization. Signed-off-by: Ard Biesheuvel Acked-by: Mark Rutland Link: https://lore.kernel.org/r/20200615101939.634391-1-ardb@kernel.org Signed-off-by: Will Deacon --- arch/arm64/Kconfig.debug | 15 --------------- arch/arm64/Makefile | 6 ------ 2 files changed, 21 deletions(-) diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug index cdf7ec0..265c446 100644 --- a/arch/arm64/Kconfig.debug +++ b/arch/arm64/Kconfig.debug @@ -8,21 +8,6 @@ config PID_IN_CONTEXTIDR instructions during context switch. Say Y here only if you are planning to use hardware trace tools with this kernel. -config ARM64_RANDOMIZE_TEXT_OFFSET - bool "Randomize TEXT_OFFSET at build time" - help - Say Y here if you want the image load offset (AKA TEXT_OFFSET) - of the kernel to be randomized at build-time. When selected, - this option will cause TEXT_OFFSET to be randomized upon any - build of the kernel, and the offset will be reflected in the - text_offset field of the resulting Image. This can be used to - fuzz-test bootloaders which respect text_offset. - - This option is intended for bootloader and/or kernel testing - only. Bootloaders must make no assumptions regarding the value - of TEXT_OFFSET and platforms must not require a specific - value. - config DEBUG_EFI depends on EFI && DEBUG_INFO bool "UEFI debugging" diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 76359cf..a0d94d0 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -121,13 +121,7 @@ endif head-y := arch/arm64/kernel/head.o # The byte offset of the kernel image in RAM from the start of RAM. -ifeq ($(CONFIG_ARM64_RANDOMIZE_TEXT_OFFSET), y) -TEXT_OFFSET := $(shell awk "BEGIN {srand(); printf \"0x%06x\n\", \ - int(2 * 1024 * 1024 / (2 ^ $(CONFIG_ARM64_PAGE_SHIFT)) * \ - rand()) * (2 ^ $(CONFIG_ARM64_PAGE_SHIFT))}") -else TEXT_OFFSET := 0x0 -endif ifeq ($(CONFIG_KASAN_SW_TAGS), y) KASAN_SHADOW_SCALE_SHIFT := 4 -- 2.7.4