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authorNick Desaulniers <ndesaulniers@google.com>2019-08-07 15:15:33 -0700
committerThomas Gleixner <tglx@linutronix.de>2019-08-08 08:25:53 +0200
commitb059f801a937d164e03b33c1848bb3dca67c0b04 (patch)
tree4cf9dd413a4b3dc9951663e08916835a5941846a /arch
parent4ce97317f41d38584fb93578e922fcd19e535f5b (diff)
download96b-common-b059f801a937d164e03b33c1848bb3dca67c0b04.tar.gz
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 = $(CC_FLAGS_FTRACE)` when CONFIG_FUNCTION_TRACER is set. Prefer that pattern to wiping out all of the important KBUILD_CFLAGS then manually having to re-add them. Seems also that __stack_chk_fail references are generated when using CONFIG_STACKPROTECTOR or CONFIG_STACKPROTECTOR_STRONG. Fixes: 8fc5b4d4121c ("purgatory: core purgatory functionality") Reported-by: Vaibhav Rustagi <vaibhavrustagi@google.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Vaibhav Rustagi <vaibhavrustagi@google.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190807221539.94583-2-ndesaulniers@google.com
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/purgatory/Makefile33
1 files changed, 28 insertions, 5 deletions
diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index 91ef244026d2..8901a1f89cf5 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -20,11 +20,34 @@ KCOV_INSTRUMENT := n
# Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That
# in turn leaves some undefined symbols like __fentry__ in purgatory and not
-# sure how to relocate those. Like kexec-tools, use custom flags.
-
-KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes -fno-zero-initialized-in-bss -fno-builtin -ffreestanding -c -Os -mcmodel=large
-KBUILD_CFLAGS += -m$(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)