Hi. 2018-04-30 10:23 GMT+09:00 Nicholas Piggin <npiggin@xxxxxxxxx>: > The powerpc toolchain can compile combinations of 32/64 bit and > big/little endian, so it's convenient to consider, e.g., > > CC -m64 -mbig-endian > > To be the C compiler for the purpose of invoking it to build > target artifacts. Right, but this is not possible in the new Kconfig scheme because CPU_BIG/LITTLE_ENDIAN can be turned on/off from Kconfig menus. > Rather than override, use kbuild defined variables to pass these > flags around. Importantly, they must be passed to things like > cc-option, so the usual cflags-y is not sufficient. This multitude > of inconsistently named variables is a mess, but it's marginally > better than overriding the toolchain because it matches what other > architectures do. > > This allows powerpc builds to work with the new kconfig macro > language branch. XXX: not exactly sure why it fails in the first > place. Without this patch, 'scripts/kconfig/conf --syncconfig Kconfig' continues eternally. This is because the change of environment variable $(CC) will trigger syncconfig. So, this patch is the right thing to do. > XXX: 32-bit builds with 64-bit toolchain gain some additional options > like -funit-at-a-time from cc-option. Unclear why that is. Build > appears to be correct otherwise. > --- > arch/powerpc/Makefile | 14 +++++++------- > 1 file changed, 7 insertions(+), 7 deletions(-) > > diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile > index 95813df90801..046b5dde9ff5 100644 > --- a/arch/powerpc/Makefile > +++ b/arch/powerpc/Makefile > @@ -74,13 +74,15 @@ endif > endif > > ifeq ($(CONFIG_CPU_LITTLE_ENDIAN),y) > -override LD += -EL > +KBUILD_CPPFLAGS += -mlittle-endian IMHO, I personally prefer KBUILD_CFLAGS += -mlittle-endian KBUILD_AFLAGS += -mlittle-endian like the current arch/powerpc/Makefile add the flag to cflags-y / aflags-y separately. Only the difference would be whether -mlittle-endian is passed to pre-processing the linker script, though. > +LDFLAGS += -EL > LDEMULATION := lppc > GNUTARGET := powerpcle > MULTIPLEWORD := -mno-multiple > KBUILD_CFLAGS_MODULE += $(call cc-option,-mno-save-toc-indirect) > else > -override LD += -EB > +KBUILD_CPPFLAGS += $(call cc-option,-mbig-endian) > +LDFLAGS += -EB > LDEMULATION := ppc > GNUTARGET := powerpc > MULTIPLEWORD := -mmultiple > @@ -93,8 +95,6 @@ aflags-$(CONFIG_CPU_BIG_ENDIAN) += $(call cc-option,-mabi=elfv1) > aflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -mabi=elfv2 > endif > > -cflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -mlittle-endian > -cflags-$(CONFIG_CPU_BIG_ENDIAN) += $(call cc-option,-mbig-endian) > ifneq ($(cc-name),clang) > cflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -mno-strict-align > endif > @@ -103,9 +103,9 @@ aflags-$(CONFIG_CPU_BIG_ENDIAN) += $(call cc-option,-mbig-endian) > aflags-$(CONFIG_CPU_LITTLE_ENDIAN) += -mlittle-endian > > ifeq ($(HAS_BIARCH),y) > -override AS += -a$(BITS) > -override LD += -m elf$(BITS)$(LDEMULATION) > -override CC += -m$(BITS) > +KBUILD_CPPFLAGS += -m$(BITS) Do you mean this? KBUILD_CFLAGS += -m$(BITS) > +KBUILD_AFLAGS += -m$(BITS) -Wl,-a$(BITS) Both KBUILD_CPPFLAGS and KBUILD_AFLAGS are added to orig_a_flags in scripts/Makefile.lib So, -m$(BITS) will be doubled for *.S files. > +LDFLAGS += -m elf$(BITS)$(LDEMULATION) > KBUILD_ARFLAGS += --target=elf$(BITS)-$(GNUTARGET) > endif > -- Best Regards Masahiro Yamada -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
