Recent versions of GCC will emit literals into a separate .rodata section
rather than interspersed with the instruction stream. We disabled this
in commit 67dfa1751ce71 ("arm64: errata: Add -mpc-relative-literal-loads
to build flags"), because it uses adrp/add pairs to reference these
literals even when building with -mcmodel=large, which breaks module
loading when we have the mitigation for Cortex-A53 erratum #843419
enabled.However, due to the recent discoveries regarding speculative execution, we should avoid putting data into executable sections, to prevent creating speculative gadgets inadvertently. So set -mpc-relative-literal-loads only for modules, and only if the A53 erratum is enabled. Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org> --- arch/arm64/Makefile | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index b481b4a7c011..bd7cb205e28a 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -26,7 +26,8 @@ ifeq ($(CONFIG_ARM64_ERRATUM_843419),y) ifeq ($(call ld-option, --fix-cortex-a53-843419),) $(warning ld does not support --fix-cortex-a53-843419; kernel may be susceptible to erratum) else -LDFLAGS_vmlinux += --fix-cortex-a53-843419 +LDFLAGS_vmlinux += --fix-cortex-a53-843419 +KBUILD_CFLAGS_MODULE += $(call cc-option, -mpc-relative-literal-loads) endif endif @@ -51,7 +52,6 @@ endif KBUILD_CFLAGS += -mgeneral-regs-only $(lseinstr) $(brokengasinst) KBUILD_CFLAGS += -fno-asynchronous-unwind-tables -KBUILD_CFLAGS += $(call cc-option, -mpc-relative-literal-loads) KBUILD_AFLAGS += $(lseinstr) $(brokengasinst) KBUILD_CFLAGS += $(call cc-option,-mabi=lp64) -- 2.11.0
