On Mon, Jul 22, 2019 at 2:33 PM Nick Desaulniers <ndesaulni...@google.com> wrote: > > 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 like arch/x86/xen/vdso/Makefile use > `CFLAGS_REMOVE_file.o = -pg` 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. > > Fixes: 8fc5b4d4121c ("purgatory: core purgatory functionality") > Reported-by: Vaibhav Rustagi <vaibhavrust...@google.com> > Suggested-by: Peter Zijlstra <pet...@infradead.org> > Signed-off-by: Nick Desaulniers <ndesaulni...@google.com> > --- > Rather than manually add -mno-sse, -mno-mmx, -mno-sse2, prefer to filter > -pg flags. > > arch/x86/purgatory/Makefile | 12 +++++++----- > 1 file changed, 7 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile > index 91ef244026d2..56bcabca283f 100644 > --- a/arch/x86/purgatory/Makefile > +++ b/arch/x86/purgatory/Makefile > @@ -20,11 +20,13 @@ 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$(BITS)
Is purgatory/kexec supported for CONFIG_X86_32? Should I be keeping `-m$(BITS)`? arch/x86/purgatory/Makefile mentions `setup-x86_$(BITS).o` which I assume is broken as there is no arch/x86/purgatory/setup-x86_32.S? > -KBUILD_CFLAGS += $(call cc-option,-fno-PIE) > +# sure how to relocate those. > +ifdef CONFIG_FUNCTION_TRACER > +CFLAGS_REMOVE_sha256.o = -pg > +CFLAGS_REMOVE_purgatory.o = -pg > +CFLAGS_REMOVE_string.o = -pg > +CFLAGS_REMOVE_kexec-purgatory.o = -pg > +endif > > $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE > $(call if_changed,ld) > -- > 2.22.0.657.g960e92d24f-goog > -- Thanks, ~Nick Desaulniers