This is a note to let you know that I've just added the patch titled arm64: errata: add module build workaround for erratum #843419 to the 4.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: arm64-errata-add-module-build-workaround-for-erratum-843419.patch and it can be found in the queue-4.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From df057cc7b4fa59e9b55f07ffdb6c62bf02e99a00 Mon Sep 17 00:00:00 2001 From: Will Deacon <will.deacon@xxxxxxx> Date: Tue, 17 Mar 2015 12:15:02 +0000 Subject: arm64: errata: add module build workaround for erratum #843419 From: Will Deacon <will.deacon@xxxxxxx> commit df057cc7b4fa59e9b55f07ffdb6c62bf02e99a00 upstream. Cortex-A53 processors <= r0p4 are affected by erratum #843419 which can lead to a memory access using an incorrect address in certain sequences headed by an ADRP instruction. There is a linker fix to generate veneers for ADRP instructions, but this doesn't work for kernel modules which are built as unlinked ELF objects. This patch adds a new config option for the erratum which, when enabled, builds kernel modules with the mcmodel=large flag. This uses absolute addressing for all kernel symbols, thereby removing the use of ADRP as a PC-relative form of addressing. The ADRP relocs are removed from the module loader so that we fail to load any potentially affected modules. Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx> Signed-off-by: Will Deacon <will.deacon@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/arm64/Kconfig | 16 ++++++++++++++++ arch/arm64/Makefile | 4 ++++ arch/arm64/kernel/module.c | 2 ++ 3 files changed, 22 insertions(+) --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -413,6 +413,22 @@ config ARM64_ERRATUM_845719 If unsure, say Y. +config ARM64_ERRATUM_843419 + bool "Cortex-A53: 843419: A load or store might access an incorrect address" + depends on MODULES + default y + help + This option builds kernel modules using the large memory model in + order to avoid the use of the ADRP instruction, which can cause + a subsequent memory access to use an incorrect address on Cortex-A53 + parts up to r0p4. + + Note that the kernel itself must be linked with a version of ld + which fixes potentially affected ADRP instructions through the + use of veneers. + + If unsure, say Y. + endmenu --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -30,6 +30,10 @@ endif CHECKFLAGS += -D__aarch64__ +ifeq ($(CONFIG_ARM64_ERRATUM_843419), y) +CFLAGS_MODULE += -mcmodel=large +endif + # Default value head-y := arch/arm64/kernel/head.o --- a/arch/arm64/kernel/module.c +++ b/arch/arm64/kernel/module.c @@ -332,12 +332,14 @@ int apply_relocate_add(Elf64_Shdr *sechd ovf = reloc_insn_imm(RELOC_OP_PREL, loc, val, 0, 21, AARCH64_INSN_IMM_ADR); break; +#ifndef CONFIG_ARM64_ERRATUM_843419 case R_AARCH64_ADR_PREL_PG_HI21_NC: overflow_check = false; case R_AARCH64_ADR_PREL_PG_HI21: ovf = reloc_insn_imm(RELOC_OP_PAGE, loc, val, 12, 21, AARCH64_INSN_IMM_ADR); break; +#endif case R_AARCH64_ADD_ABS_LO12_NC: case R_AARCH64_LDST8_ABS_LO12_NC: overflow_check = false; Patches currently in stable-queue which might be from will.deacon@xxxxxxx are queue-4.1/arm64-head.s-initialise-mdcr_el2-in-el2_setup.patch queue-4.1/arm64-set-max_memblock_addr-according-to-linear-region-size.patch queue-4.1/arm64-kconfig-move-list_poison-to-a-safe-value.patch queue-4.1/arm64-flush-fp-simd-state-correctly-after-execve.patch queue-4.1/kvm-arm64-add-workaround-for-cortex-a57-erratum-852523.patch queue-4.1/of-fdt-make-memblock-maximum-physical-address-arch-configurable.patch queue-4.1/arm64-errata-add-module-build-workaround-for-erratum-843419.patch queue-4.1/arm64-compat-fix-vfp-save-restore-across-signal-handlers-in-big-endian.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html