From: Segher Boessenkool Date: Thu, 1 Mar 2018 01:02:49 +0000 (-0800) Subject: powerpc: Keep const vars out of writable .sdata X-Git-Tag: v4.17-rc1~86^2~180 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=51d42f0f5fd6c74144d19bf6a663521e2ea99765;p=thirdparty%2Fkernel%2Flinux.git powerpc: Keep const vars out of writable .sdata Newer gcc will support "-mno-readonly-in-sdata"[1], which makes sure that the optimization on PPC32 for variables getting moved into the .sdata section will not apply to const variables (which must be in .rodata). This was originally noticed in mm/rodata_test.c when rodata_test_data was not static: c0695034 g O .data 00000004 rodata_test_data After this patch with an updated compiler, this is correctly in .rodata. [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82411 Reported-by: Christophe Leroy Signed-off-by: Segher Boessenkool Signed-off-by: Kees Cook Signed-off-by: Michael Ellerman --- diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index ccd2556bdb530..c7628e9730842 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -141,7 +141,9 @@ AFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mabi=elfv1) endif CFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mcmodel=medium,$(call cc-option,-mminimal-toc)) CFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mno-pointers-to-nested-functions) + CFLAGS-$(CONFIG_PPC32) := -ffixed-r2 $(MULTIPLEWORD) +CFLAGS-$(CONFIG_PPC32) += $(call cc-option,-mno-readonly-in-sdata) ifeq ($(CONFIG_PPC_BOOK3S_64),y) CFLAGS-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=power7,-mtune=power4)