On Fri, Aug 26, 2022 at 11:21 AM Nathan Chancellor <nathan@xxxxxxxxxx> wrote: > > Hi Nick, > > I think the title would be a little more readable if it was: > > Makefile.compiler: Use KBUILD_AFLAGS for as-option Thanks, yeah that looks better; I expect a v2 of this series will be necessary. > > On Fri, Aug 26, 2022 at 11:10:33AM -0700, Nick Desaulniers wrote: > > as-instr uses KBUILD_AFLAGS, but as-option uses KBUILD_CFLAGS. This can > > cause as-option to fail unexpectedly because clang will emit > > -Werror,-Wunused-command-line-argument for various -m and -f flags for > > assembler sources. > > > > Callers of as-option (and as-instr) likely want to be adding flags to > > KBUILD_AFLAGS/aflags-y, not KBUILD_CFLAGS/cflags-y. > > > > Link: https://github.com/ClangBuiltLinux/linux/issues/1699 > > Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> > > --- > > arch/x86/boot/compressed/Makefile | 5 +++-- > > scripts/Makefile.compiler | 6 +++--- > > 2 files changed, 6 insertions(+), 5 deletions(-) > > > > diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile > > index 35ce1a64068b..fb3db714a028 100644 > > --- a/arch/x86/boot/compressed/Makefile > > +++ b/arch/x86/boot/compressed/Makefile > > @@ -48,8 +48,6 @@ KBUILD_CFLAGS += -Wno-pointer-sign > > KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=) > > KBUILD_CFLAGS += -fno-asynchronous-unwind-tables > > KBUILD_CFLAGS += -D__DISABLE_EXPORTS > > -# Disable relocation relaxation in case the link is not PIE. > > -KBUILD_CFLAGS += $(call as-option,-Wa$(comma)-mrelax-relocations=no) > > KBUILD_CFLAGS += -include $(srctree)/include/linux/hidden.h > > > > # sev.c indirectly inludes inat-table.h which is generated during > > @@ -58,6 +56,9 @@ KBUILD_CFLAGS += -include $(srctree)/include/linux/hidden.h > > CFLAGS_sev.o += -I$(objtree)/arch/x86/lib/ > > > > KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__ > > +# Disable relocation relaxation in case the link is not PIE. > > +KBUILD_AFLAGS += $(call as-option,-Wa$(comma)-mrelax-relocations=no) > > + > > Commit 09e43968db40 ("x86/boot/compressed: Disable relocation > relaxation") added this to address > https://github.com/ClangBuiltLinux/linux/issues/1121, is it correct to > move it to only being used for the .S files in arch/x86/boot/compressed? + Arvind Hmm...that makes me think we might need two different as-option flags; one that does use KBUILD_CFLAGS, and whose result is meant to be added to cflags-y, then another that uses KBUILD_AFLAGS and is added to aflagsy-y. (My patch 2/3 in the series would use the latter) Let's see what thoughts Masahiro has. > > > GCOV_PROFILE := n > > UBSAN_SANITIZE :=n > > > > diff --git a/scripts/Makefile.compiler b/scripts/Makefile.compiler > > index 94d0d40cddb3..d1739f0d3ce3 100644 > > --- a/scripts/Makefile.compiler > > +++ b/scripts/Makefile.compiler > > @@ -29,13 +29,13 @@ try-run = $(shell set -e; \ > > fi) > > > > # as-option > > -# Usage: cflags-y += $(call as-option,-Wa$(comma)-isa=foo,) > > +# Usage: aflags-y += $(call as-option,-Wa$(comma)-isa=foo,) > > > > as-option = $(call try-run,\ > > - $(CC) $(KBUILD_CFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2)) > > + $(CC) $(KBUILD_AFLAGS) $(1) -c -x assembler /dev/null -o "$$TMP",$(1),$(2)) > > > > # as-instr > > -# Usage: cflags-y += $(call as-instr,instr,option1,option2) > > +# Usage: aflags-y += $(call as-instr,instr,option1,option2) > > > > as-instr = $(call try-run,\ > > printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3)) > > -- > > 2.37.2.672.g94769d06f0-goog > > -- Thanks, ~Nick Desaulniers
