From b059f801a937d164e03b33c1848bb3dca67c0b04 Mon Sep 17 00:00:00 2001 From: Nick Desaulniers Date: Wed, 7 Aug 2019 15:15:33 -0700 Subject: x86/purgatory: Use CFLAGS_REMOVE rather than reset KBUILD_CFLAGS KBUILD_CFLAGS is very carefully built up in the top level Makefile, particularly when cross compiling or using different build tools. Resetting KBUILD_CFLAGS via := assignment is an antipattern. The comment above the reset mentions that -pg is problematic. Other Makefiles use `CFLAGS_REMOVE_file.o = $(CC_FLAGS_FTRACE)` when CONFIG_FUNCTION_TRACER is set. Prefer that pattern to wiping out all of the important KBUILD_CFLAGS then manually having to re-add them. Seems also that __stack_chk_fail references are generated when using CONFIG_STACKPROTECTOR or CONFIG_STACKPROTECTOR_STRONG. Fixes: 8fc5b4d4121c ("purgatory: core purgatory functionality") Reported-by: Vaibhav Rustagi Suggested-by: Peter Zijlstra Suggested-by: Thomas Gleixner Signed-off-by: Nick Desaulniers Signed-off-by: Thomas Gleixner Tested-by: Vaibhav Rustagi Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190807221539.94583-2-ndesaulniers@google.com --- arch/x86/purgatory/Makefile | 33 ++++++++++++++++++++++++++++----- 1 file changed, 28 insertions(+), 5 deletions(-) (limited to 'arch/x86/purgatory') diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile index 91ef244026d2..8901a1f89cf5 100644 --- a/arch/x86/purgatory/Makefile +++ b/arch/x86/purgatory/Makefile @@ -20,11 +20,34 @@ KCOV_INSTRUMENT := n # Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That # in turn leaves some undefined symbols like __fentry__ in purgatory and not -# sure how to relocate those. Like kexec-tools, use custom flags. - -KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes -fno-zero-initialized-in-bss -fno-builtin -ffreestanding -c -Os -mcmodel=large -KBUILD_CFLAGS += -m$(BITS) -KBUILD_CFLAGS += $(call cc-option,-fno-PIE) +# sure how to relocate those. +ifdef CONFIG_FUNCTION_TRACER +CFLAGS_REMOVE_sha256.o += $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_purgatory.o += $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_string.o += $(CC_FLAGS_FTRACE) +CFLAGS_REMOVE_kexec-purgatory.o += $(CC_FLAGS_FTRACE) +endif + +ifdef CONFIG_STACKPROTECTOR +CFLAGS_REMOVE_sha256.o += -fstack-protector +CFLAGS_REMOVE_purgatory.o += -fstack-protector +CFLAGS_REMOVE_string.o += -fstack-protector +CFLAGS_REMOVE_kexec-purgatory.o += -fstack-protector +endif + +ifdef CONFIG_STACKPROTECTOR_STRONG +CFLAGS_REMOVE_sha256.o += -fstack-protector-strong +CFLAGS_REMOVE_purgatory.o += -fstack-protector-strong +CFLAGS_REMOVE_string.o += -fstack-protector-strong +CFLAGS_REMOVE_kexec-purgatory.o += -fstack-protector-strong +endif + +ifdef CONFIG_RETPOLINE +CFLAGS_REMOVE_sha256.o += $(RETPOLINE_CFLAGS) +CFLAGS_REMOVE_purgatory.o += $(RETPOLINE_CFLAGS) +CFLAGS_REMOVE_string.o += $(RETPOLINE_CFLAGS) +CFLAGS_REMOVE_kexec-purgatory.o += $(RETPOLINE_CFLAGS) +endif $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE $(call if_changed,ld) -- cgit v1.2.3