Hi. 2018-06-12 20:50 GMT+09:00 Nadav Amit <namit@xxxxxxxxxx>: > Using macros for inline assembly improves both readability and > compilation decisions that are distorted by big assembly blocks that use > alternative sections. Compile macros.S and use it to assemble all C > files. Currently, only x86 will use it. > > Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> > Cc: Michal Marek <michal.lkml@xxxxxxxxxxx> > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> > Cc: x86@xxxxxxxxxx > Cc: linux-kbuild@xxxxxxxxxxxxxxx > > Signed-off-by: Nadav Amit <namit@xxxxxxxxxx> I have not fully understood this series yet. I do not have enough skill in x86 architecture, but just some comments from the build system point of view. I guess this will probably break the parallel building. Kbuild can build 'prepare' and 'scripts' simultaneously. I locally modified the following line: diff --git a/Makefile b/Makefile index 2dea909440..6ad484a 100644 --- a/Makefile +++ b/Makefile @@ -1030,7 +1030,7 @@ $(sort $(vmlinux-deps)): $(vmlinux-dirs) ; # Error messages still appears in the original language PHONY += $(vmlinux-dirs) -$(vmlinux-dirs): prepare scripts +$(vmlinux-dirs): scripts prepare $(Q)$(MAKE) $(build)=$@ need-builtin=1 define filechk_kernel.release masahiro@grover:~/workspace/linux-kbuild$ make defconfig HOSTCC scripts/basic/fixdep HOSTCC scripts/kconfig/conf.o YACC scripts/kconfig/zconf.tab.c LEX scripts/kconfig/zconf.lex.c HOSTCC scripts/kconfig/zconf.tab.o HOSTLD scripts/kconfig/conf *** Default configuration is based on 'x86_64_defconfig' # # configuration written to .config # masahiro@grover:~/workspace/linux-kbuild$ make all scripts/kconfig/conf --syncconfig Kconfig WRAP arch/x86/include/generated/uapi/asm/bpf_perf_event.h WRAP arch/x86/include/generated/uapi/asm/poll.h WRAP arch/x86/include/generated/asm/dma-contiguous.h WRAP arch/x86/include/generated/asm/early_ioremap.h WRAP arch/x86/include/generated/asm/mcs_spinlock.h WRAP arch/x86/include/generated/asm/mm-arch-hooks.h CC scripts/mod/empty.o Assembler messages: Error: can't open arch/x86/kernel/macros.s for reading: No such file or directory make[2]: *** [scripts/Makefile.build:318: scripts/mod/empty.o] Error 1 make[1]: *** [scripts/Makefile.build:558: scripts/mod] Error 2 make: *** [Makefile:1050: scripts] Error 2 > --- > Makefile | 9 +++++++-- > arch/x86/Makefile | 11 +++++++++-- > arch/x86/kernel/Makefile | 6 ++++++ > arch/x86/kernel/macros.S | 7 +++++++ > scripts/Kbuild.include | 4 +++- > 5 files changed, 32 insertions(+), 5 deletions(-) > create mode 100644 arch/x86/kernel/macros.S > > diff --git a/Makefile b/Makefile > index 554dcaddbce4..026586db2f26 100644 > --- a/Makefile > +++ b/Makefile > @@ -1085,7 +1085,7 @@ scripts: scripts_basic include/config/auto.conf include/config/tristate.conf \ > # version.h and scripts_basic is processed / created. > > # Listed in dependency order > -PHONY += prepare archprepare prepare0 prepare1 prepare2 prepare3 > +PHONY += prepare archprepare macroprepare prepare0 prepare1 prepare2 prepare3 > > # prepare3 is used to check if we are building in a separate output directory, > # and if so do: > @@ -1109,7 +1109,9 @@ prepare1: prepare2 $(version_h) $(autoksyms_h) include/generated/utsrelease.h \ > include/config/auto.conf > $(cmd_crmodverdir) > > -archprepare: archheaders archscripts prepare1 scripts_basic > +macroprepare: prepare1 archmacros > + > +archprepare: archheaders archscripts macroprepare scripts_basic Are you planning to support for all architectures, or x86-specific? Currently, there are some hooks to do arch-specific things such as 'archprepare', 'archscripts'. > prepare0: archprepare gcc-plugins > $(Q)$(MAKE) $(build)=. > @@ -1214,6 +1216,9 @@ archheaders: > PHONY += archscripts > archscripts: > > +PHONY += archmacros > +archmacros: > + > PHONY += __headers > __headers: $(version_h) scripts_basic uapi-asm-generic archheaders archscripts > $(Q)$(MAKE) $(build)=scripts build_unifdef > diff --git a/arch/x86/Makefile b/arch/x86/Makefile > index 60135cbd905c..6b82314776fd 100644 > --- a/arch/x86/Makefile > +++ b/arch/x86/Makefile > @@ -235,8 +235,8 @@ ifdef CONFIG_X86_64 > LDFLAGS += $(call ld-option, -z max-page-size=0x200000) > endif > > -# Speed up the build > -KBUILD_CFLAGS += -pipe > +# We cannot use -pipe flag since we give an additional .s file to the compiler > +#KBUILD_CFLAGS += -pipe > # Workaround for a gcc prelease that unfortunately was shipped in a suse release > KBUILD_CFLAGS += -Wno-sign-compare > # > @@ -258,11 +258,18 @@ archscripts: scripts_basic > archheaders: > $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all > > +archmacros: > + $(Q)$(MAKE) $(build)=arch/x86/kernel macros > + > archprepare: > ifeq ($(CONFIG_KEXEC_FILE),y) > $(Q)$(MAKE) $(build)=arch/x86/purgatory arch/x86/purgatory/kexec-purgatory.c > endif > > +ASM_MACRO_FLAGS = -Wa,arch/x86/kernel/macros.s > +export ASM_MACRO_FLAGS > +KBUILD_CFLAGS += $(ASM_MACRO_FLAGS) > + > ### > # Kernel objects > > diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile > index 02d6f5cf4e70..fdb6c5b2a922 100644 > --- a/arch/x86/kernel/Makefile > +++ b/arch/x86/kernel/Makefile > @@ -9,6 +9,12 @@ extra-y += ebda.o > extra-y += platform-quirks.o > extra-y += vmlinux.lds > > +$(obj)/macros.s: $(obj)/macros.S FORCE > + $(call if_changed_dep,cpp_s_S) This is unnecessary. Kbuild will find the correct pattern rule in scripts/Makefile.build > +macros: $(obj)/macros.s > + @: If you add a phony target, it should be added to 'PHONY'. Like this: PHONY += macros macros: $(obj)/macros.s @: > CPPFLAGS_vmlinux.lds += -U$(UTS_MACHINE) > > ifdef CONFIG_FUNCTION_TRACER > diff --git a/arch/x86/kernel/macros.S b/arch/x86/kernel/macros.S > new file mode 100644 > index 000000000000..cfc1c7d1a6eb > --- /dev/null > +++ b/arch/x86/kernel/macros.S > @@ -0,0 +1,7 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > + > +/* > + * This file includes headers whose assembly part includes macros which are > + * commonly used. The macros are precompiled into assmebly file which is later > + * assembled together with each compiled file. > + */ > diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include > index 50cee534fd64..ad2c02062aa4 100644 > --- a/scripts/Kbuild.include > +++ b/scripts/Kbuild.include > @@ -189,7 +189,9 @@ __cc-option = $(call try-run-cached,\ > > # Do not attempt to build with gcc plugins during cc-option tests. > # (And this uses delayed resolution so the flags will be up to date.) > -CC_OPTION_CFLAGS = $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS)) > +# In addition, do not include the asm macros which are built later. > +CC_OPTION_FILTERED = $(GCC_PLUGINS_CFLAGS) $(ASM_MACRO_FLAGS) > +CC_OPTION_CFLAGS = $(filter-out $(CC_OPTION_FILTERED),$(KBUILD_CFLAGS)) > > # cc-option > # Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586) > -- > 2.17.0 > -- 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