| Message ID | 20240917141725.466514-20-masahiroy@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | kbuild: support building external modules in a separate build directory | expand |
On Tue, Sep 17, 2024 at 11:16:47PM +0900, Masahiro Yamada wrote: > There has been a long-standing request to support building external > modules in a separate build directory. > > This commit introduces a new environment variable, KBUILD_EXTMOD_OUTPUT, > and its shorthand Make variable, MO. > > A simple usage: > > $ make -C <kernel-dir> M=<module-src-dir> MO=<module-build-dir> > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > --- > > Documentation/kbuild/kbuild.rst | 8 +++++- > Documentation/kbuild/modules.rst | 5 +++- > Makefile | 44 +++++++++++++++++++++++--------- > 3 files changed, 43 insertions(+), 14 deletions(-) > > diff --git a/Documentation/kbuild/kbuild.rst b/Documentation/kbuild/kbuild.rst > index 716f6fb70829..66a9dc44ea28 100644 > --- a/Documentation/kbuild/kbuild.rst > +++ b/Documentation/kbuild/kbuild.rst > @@ -132,12 +132,18 @@ Specify the output directory when building the kernel. > This variable can also be used to point to the kernel output directory when > building external modules using kernel build artifacts in a separate build > directory. Please note that this does NOT specify the output directory for the > -external modules themselves. > +external modules themselves. (Use KBUILD_EXTMOD_OUTPUT for that purpose.) > > The output directory can also be specified using "O=...". > > Setting "O=..." takes precedence over KBUILD_OUTPUT. > > +KBUILD_EXTMOD_OUTPUT > +-------------------- > +Specify the output directory for external modules. > + > +Setting "MO=..." takes precedence over KBUILD_EXTMOD_OUTPUT. > + > KBUILD_EXTRA_WARN > ----------------- > Specify the extra build checks. The same value can be assigned by passing > diff --git a/Documentation/kbuild/modules.rst b/Documentation/kbuild/modules.rst > index 3a6e7bdc0889..03347e13eeb5 100644 > --- a/Documentation/kbuild/modules.rst > +++ b/Documentation/kbuild/modules.rst > @@ -95,7 +95,7 @@ executed to make module versioning work. > of the kernel output directory if the kernel was built in a separate > build directory.) > > - make -C $KDIR M=$PWD > + make -C $KDIR M=$PWD [MO=$BUILD_DIR] > > -C $KDIR > The directory that contains the kernel and relevant build > @@ -109,6 +109,9 @@ executed to make module versioning work. > directory where the external module (kbuild file) is > located. > > + MO=$BUILD_DIR > + Speficies a separate output directory for the external module. s/Speficies/Specifies/ > + > 2.3 Targets > =========== > > diff --git a/Makefile b/Makefile > index 9fbf7ef6e394..b654baa0763a 100644 > --- a/Makefile > +++ b/Makefile > @@ -134,6 +134,10 @@ ifeq ("$(origin M)", "command line") > KBUILD_EXTMOD := $(M) > endif > > +ifeq ("$(origin MO)", "command line") > + KBUILD_EXTMOD_OUTPUT := $(MO) > +endif > + > $(if $(word 2, $(KBUILD_EXTMOD)), \ > $(error building multiple external modules is not supported)) Should we also check against multiple output directories? > > @@ -187,7 +191,11 @@ ifdef KBUILD_EXTMOD > else > objtree := $(CURDIR) > endif > - output := $(KBUILD_EXTMOD) > + output := $(or $(KBUILD_EXTMOD_OUTPUT),$(KBUILD_EXTMOD)) > + # KBUILD_EXTMOD might be a relative path. Remember its absolute path before > + # Make changes the working directory. > + export abs_extmodtree := $(realpath $(KBUILD_EXTMOD)) > + $(if $(abs_extmodtree),,$(error specified external module directory "$(KBUILD_EXTMOD)" does not exist)) > else > objtree := . > output := $(KBUILD_OUTPUT) > @@ -246,7 +254,6 @@ else # need-sub-make > ifeq ($(abs_srctree),$(CURDIR)) > # building in the source tree > srctree := . > - building_out_of_srctree := > else > ifeq ($(abs_srctree)/,$(dir $(CURDIR))) > # building in a subdirectory of the source tree > @@ -254,22 +261,23 @@ else > else > srctree := $(abs_srctree) > endif > - building_out_of_srctree := 1 > endif > > ifneq ($(KBUILD_ABS_SRCTREE),) > srctree := $(abs_srctree) > endif > > -VPATH := > +export srctree > > -ifeq ($(KBUILD_EXTMOD),) > -ifdef building_out_of_srctree > -VPATH := $(srctree) > -endif > -endif > +_vpath = $(or $(abs_extmodtree),$(srctree)) > > -export building_out_of_srctree srctree VPATH > +ifeq ($(realpath $(_vpath)),$(CURDIR)) Just a style consistency question: 'ifeq (,)' with a space after ',' (as a few lines above) or without as used here? > +building_out_of_srctree := > +VPATH := > +else > +export building_out_of_srctree := 1 > +export VPATH := $(_vpath) > +endif > > # To make sure we do not include .config for any of the *config targets > # catch them early, and hand them over to scripts/kconfig/Makefile > @@ -550,7 +558,7 @@ USERINCLUDE := \ > LINUXINCLUDE := \ > -I$(srctree)/arch/$(SRCARCH)/include \ > -I$(objtree)/arch/$(SRCARCH)/include/generated \ > - $(if $(building_out_of_srctree),-I$(srctree)/include) \ > + -I$(srctree)/include \ > -I$(objtree)/include \ > $(USERINCLUDE) > > @@ -640,6 +648,7 @@ quiet_cmd_makefile = GEN Makefile > } > Makefile > > outputmakefile: > +ifeq ($(KBUILD_EXTMOD),) > @if [ -f $(srctree)/.config -o \ > -d $(srctree)/include/config -o \ > -d $(srctree)/arch/$(SRCARCH)/include/generated ]; then \ > @@ -649,7 +658,16 @@ outputmakefile: > echo >&2 "***"; \ > false; \ > fi > - $(Q)ln -fsn $(srctree) source > +else > + @if [ -f $(KBUILD_EXTMOD)/modules.order ]; then \ > + echo >&2 "***"; \ > + echo >&2 "*** The external module source tree is not clean."; \ > + echo >&2 "*** Please run 'make -C $(abs_srctree) M=$(realpath $(KBUILD_EXTMOD)) clean'"; \ > + echo >&2 "***"; \ > + false; \ > + fi > +endif > + $(Q)ln -fsn $(_vpath) source > $(call cmd,makefile) > $(Q)test -e .gitignore || \ > { echo "# this is build directory, ignore it"; echo "*"; } > .gitignore > @@ -1926,6 +1944,8 @@ KBUILD_MODULES := 1 > > endif > > +prepare: outputmakefile > + > # Preset locale variables to speed up the build process. Limit locale > # tweaks to this spot to avoid wrong language settings when running > # make menuconfig etc. > -- > 2.43.0 > Thanks, this feature is really appreciated by a lot of my colleagues, and I think you found quite a nice solution! I'm a bit surprised, that there are not some more testers ... Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
On Thu, Oct 03, 2024 at 09:47:35PM +0200, Nicolas Schier wrote: > On Tue, Sep 17, 2024 at 11:16:47PM +0900, Masahiro Yamada wrote: > > There has been a long-standing request to support building external > > modules in a separate build directory. > > > > This commit introduces a new environment variable, KBUILD_EXTMOD_OUTPUT, > > and its shorthand Make variable, MO. > > > > A simple usage: > > > > $ make -C <kernel-dir> M=<module-src-dir> MO=<module-build-dir> > > > > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> > > --- > > > > Documentation/kbuild/kbuild.rst | 8 +++++- > > Documentation/kbuild/modules.rst | 5 +++- > > Makefile | 44 +++++++++++++++++++++++--------- > > 3 files changed, 43 insertions(+), 14 deletions(-) > > > > diff --git a/Documentation/kbuild/kbuild.rst b/Documentation/kbuild/kbuild.rst > > index 716f6fb70829..66a9dc44ea28 100644 > > --- a/Documentation/kbuild/kbuild.rst > > +++ b/Documentation/kbuild/kbuild.rst > > @@ -132,12 +132,18 @@ Specify the output directory when building the kernel. > > This variable can also be used to point to the kernel output directory when > > building external modules using kernel build artifacts in a separate build > > directory. Please note that this does NOT specify the output directory for the > > -external modules themselves. > > +external modules themselves. (Use KBUILD_EXTMOD_OUTPUT for that purpose.) > > > > The output directory can also be specified using "O=...". > > > > Setting "O=..." takes precedence over KBUILD_OUTPUT. > > > > +KBUILD_EXTMOD_OUTPUT > > +-------------------- > > +Specify the output directory for external modules. > > + > > +Setting "MO=..." takes precedence over KBUILD_EXTMOD_OUTPUT. > > + > > KBUILD_EXTRA_WARN > > ----------------- > > Specify the extra build checks. The same value can be assigned by passing > > diff --git a/Documentation/kbuild/modules.rst b/Documentation/kbuild/modules.rst > > index 3a6e7bdc0889..03347e13eeb5 100644 > > --- a/Documentation/kbuild/modules.rst > > +++ b/Documentation/kbuild/modules.rst > > @@ -95,7 +95,7 @@ executed to make module versioning work. > > of the kernel output directory if the kernel was built in a separate > > build directory.) > > > > - make -C $KDIR M=$PWD > > + make -C $KDIR M=$PWD [MO=$BUILD_DIR] > > > > -C $KDIR > > The directory that contains the kernel and relevant build > > @@ -109,6 +109,9 @@ executed to make module versioning work. > > directory where the external module (kbuild file) is > > located. > > > > + MO=$BUILD_DIR > > + Speficies a separate output directory for the external module. > > s/Speficies/Specifies/ > > > + > > 2.3 Targets > > =========== > > > > diff --git a/Makefile b/Makefile > > index 9fbf7ef6e394..b654baa0763a 100644 > > --- a/Makefile > > +++ b/Makefile > > @@ -134,6 +134,10 @@ ifeq ("$(origin M)", "command line") > > KBUILD_EXTMOD := $(M) > > endif > > > > +ifeq ("$(origin MO)", "command line") > > + KBUILD_EXTMOD_OUTPUT := $(MO) > > +endif > > + > > $(if $(word 2, $(KBUILD_EXTMOD)), \ > > $(error building multiple external modules is not supported)) > > Should we also check against multiple output directories? > > > > > @@ -187,7 +191,11 @@ ifdef KBUILD_EXTMOD > > else > > objtree := $(CURDIR) > > endif > > - output := $(KBUILD_EXTMOD) > > + output := $(or $(KBUILD_EXTMOD_OUTPUT),$(KBUILD_EXTMOD)) > > + # KBUILD_EXTMOD might be a relative path. Remember its absolute path before > > + # Make changes the working directory. > > + export abs_extmodtree := $(realpath $(KBUILD_EXTMOD)) > > + $(if $(abs_extmodtree),,$(error specified external module directory "$(KBUILD_EXTMOD)" does not exist)) > > else > > objtree := . > > output := $(KBUILD_OUTPUT) > > @@ -246,7 +254,6 @@ else # need-sub-make > > ifeq ($(abs_srctree),$(CURDIR)) > > # building in the source tree > > srctree := . > > - building_out_of_srctree := > > else > > ifeq ($(abs_srctree)/,$(dir $(CURDIR))) > > # building in a subdirectory of the source tree > > @@ -254,22 +261,23 @@ else > > else > > srctree := $(abs_srctree) > > endif > > - building_out_of_srctree := 1 > > endif > > > > ifneq ($(KBUILD_ABS_SRCTREE),) > > srctree := $(abs_srctree) > > endif > > > > -VPATH := > > +export srctree > > > > -ifeq ($(KBUILD_EXTMOD),) > > -ifdef building_out_of_srctree > > -VPATH := $(srctree) > > -endif > > -endif > > +_vpath = $(or $(abs_extmodtree),$(srctree)) > > > > -export building_out_of_srctree srctree VPATH > > +ifeq ($(realpath $(_vpath)),$(CURDIR)) > > Just a style consistency question: 'ifeq (,)' with a space after ',' (as a few > lines above) or without as used here? > > > +building_out_of_srctree := > > +VPATH := > > +else > > +export building_out_of_srctree := 1 > > +export VPATH := $(_vpath) > > +endif > > > > # To make sure we do not include .config for any of the *config targets > > # catch them early, and hand them over to scripts/kconfig/Makefile > > @@ -550,7 +558,7 @@ USERINCLUDE := \ > > LINUXINCLUDE := \ > > -I$(srctree)/arch/$(SRCARCH)/include \ > > -I$(objtree)/arch/$(SRCARCH)/include/generated \ > > - $(if $(building_out_of_srctree),-I$(srctree)/include) \ > > + -I$(srctree)/include \ > > -I$(objtree)/include \ > > $(USERINCLUDE) > > > > @@ -640,6 +648,7 @@ quiet_cmd_makefile = GEN Makefile > > } > Makefile > > > > outputmakefile: > > +ifeq ($(KBUILD_EXTMOD),) > > @if [ -f $(srctree)/.config -o \ > > -d $(srctree)/include/config -o \ > > -d $(srctree)/arch/$(SRCARCH)/include/generated ]; then \ > > @@ -649,7 +658,16 @@ outputmakefile: > > echo >&2 "***"; \ > > false; \ > > fi > > - $(Q)ln -fsn $(srctree) source > > +else > > + @if [ -f $(KBUILD_EXTMOD)/modules.order ]; then \ If I do make O=build touch fs/btrfs/modules.order make O=build M=fs/btrfs/ MO=/tmp/btrfs CONFIG_BTRFS_FS=m the 'modules.order' check does not work correctly. But a consequtive make -C /tmp/btrfs CONFIG_BTRFS_FS=m shows the 'The external module source tree is not clean.' message as expected. If I replace $(KBUILD_EXTMOD) by $(abs_extmodtree), it works for me also in the first case. Kind regards, Nicolas
On Fri, Oct 4, 2024 at 4:47 AM Nicolas Schier <nicolas@fjasle.eu> wrote: > > @@ -109,6 +109,9 @@ executed to make module versioning work. > > directory where the external module (kbuild file) is > > located. > > > > + MO=$BUILD_DIR > > + Speficies a separate output directory for the external module. > > s/Speficies/Specifies/ Thanks, I will fix. > > > + > > 2.3 Targets > > =========== > > > > diff --git a/Makefile b/Makefile > > index 9fbf7ef6e394..b654baa0763a 100644 > > --- a/Makefile > > +++ b/Makefile > > @@ -134,6 +134,10 @@ ifeq ("$(origin M)", "command line") > > KBUILD_EXTMOD := $(M) > > endif > > > > +ifeq ("$(origin MO)", "command line") > > + KBUILD_EXTMOD_OUTPUT := $(MO) > > +endif > > + > > $(if $(word 2, $(KBUILD_EXTMOD)), \ > > $(error building multiple external modules is not supported)) > > Should we also check against multiple output directories? I do not think so. When a directory path contains a space, it should be treated as-is, in general. However, GNU Make is not good at handling spaces in files paths. So, this will fail eventually (with a little more obscure way). $ make O=build M=fs/btrfs MO='/tmp/AA BB/btffs' Makefile:214: *** failed to create output directory "/tmp/AA BB/btffs". Stop. > > -export building_out_of_srctree srctree VPATH > > +ifeq ($(realpath $(_vpath)),$(CURDIR)) > > Just a style consistency question: 'ifeq (,)' with a space after ',' (as a few > lines above) or without as used here? Maybe, we should keep consistency. But, this line will be removed in v2. -- Best Regards Masahiro Yamada
On Sat, Oct 5, 2024 at 4:45 AM Nicolas Schier <nicolas@fjasle.eu> wrote: > > > @@ -640,6 +648,7 @@ quiet_cmd_makefile = GEN Makefile > > > } > Makefile > > > > > > outputmakefile: > > > +ifeq ($(KBUILD_EXTMOD),) > > > @if [ -f $(srctree)/.config -o \ > > > -d $(srctree)/include/config -o \ > > > -d $(srctree)/arch/$(SRCARCH)/include/generated ]; then \ > > > @@ -649,7 +658,16 @@ outputmakefile: > > > echo >&2 "***"; \ > > > false; \ > > > fi > > > - $(Q)ln -fsn $(srctree) source > > > +else > > > + @if [ -f $(KBUILD_EXTMOD)/modules.order ]; then \ > > If I do > > make O=build > touch fs/btrfs/modules.order > make O=build M=fs/btrfs/ MO=/tmp/btrfs CONFIG_BTRFS_FS=m > > the 'modules.order' check does not work correctly. But a consequtive > > make -C /tmp/btrfs CONFIG_BTRFS_FS=m > > shows the 'The external module source tree is not clean.' message as > expected. > > If I replace $(KBUILD_EXTMOD) by $(abs_extmodtree), it works for me also > in the first case. Right, this check does not work correctly when KBUILD_EXTMOD is a relative path. In v2, I changed this part. -- Best Regards Masahiro Yamada
diff --git a/Documentation/kbuild/kbuild.rst b/Documentation/kbuild/kbuild.rst index 716f6fb70829..66a9dc44ea28 100644 --- a/Documentation/kbuild/kbuild.rst +++ b/Documentation/kbuild/kbuild.rst @@ -132,12 +132,18 @@ Specify the output directory when building the kernel. This variable can also be used to point to the kernel output directory when building external modules using kernel build artifacts in a separate build directory. Please note that this does NOT specify the output directory for the -external modules themselves. +external modules themselves. (Use KBUILD_EXTMOD_OUTPUT for that purpose.) The output directory can also be specified using "O=...". Setting "O=..." takes precedence over KBUILD_OUTPUT. +KBUILD_EXTMOD_OUTPUT +-------------------- +Specify the output directory for external modules. + +Setting "MO=..." takes precedence over KBUILD_EXTMOD_OUTPUT. + KBUILD_EXTRA_WARN ----------------- Specify the extra build checks. The same value can be assigned by passing diff --git a/Documentation/kbuild/modules.rst b/Documentation/kbuild/modules.rst index 3a6e7bdc0889..03347e13eeb5 100644 --- a/Documentation/kbuild/modules.rst +++ b/Documentation/kbuild/modules.rst @@ -95,7 +95,7 @@ executed to make module versioning work. of the kernel output directory if the kernel was built in a separate build directory.) - make -C $KDIR M=$PWD + make -C $KDIR M=$PWD [MO=$BUILD_DIR] -C $KDIR The directory that contains the kernel and relevant build @@ -109,6 +109,9 @@ executed to make module versioning work. directory where the external module (kbuild file) is located. + MO=$BUILD_DIR + Speficies a separate output directory for the external module. + 2.3 Targets =========== diff --git a/Makefile b/Makefile index 9fbf7ef6e394..b654baa0763a 100644 --- a/Makefile +++ b/Makefile @@ -134,6 +134,10 @@ ifeq ("$(origin M)", "command line") KBUILD_EXTMOD := $(M) endif +ifeq ("$(origin MO)", "command line") + KBUILD_EXTMOD_OUTPUT := $(MO) +endif + $(if $(word 2, $(KBUILD_EXTMOD)), \ $(error building multiple external modules is not supported)) @@ -187,7 +191,11 @@ ifdef KBUILD_EXTMOD else objtree := $(CURDIR) endif - output := $(KBUILD_EXTMOD) + output := $(or $(KBUILD_EXTMOD_OUTPUT),$(KBUILD_EXTMOD)) + # KBUILD_EXTMOD might be a relative path. Remember its absolute path before + # Make changes the working directory. + export abs_extmodtree := $(realpath $(KBUILD_EXTMOD)) + $(if $(abs_extmodtree),,$(error specified external module directory "$(KBUILD_EXTMOD)" does not exist)) else objtree := . output := $(KBUILD_OUTPUT) @@ -246,7 +254,6 @@ else # need-sub-make ifeq ($(abs_srctree),$(CURDIR)) # building in the source tree srctree := . - building_out_of_srctree := else ifeq ($(abs_srctree)/,$(dir $(CURDIR))) # building in a subdirectory of the source tree @@ -254,22 +261,23 @@ else else srctree := $(abs_srctree) endif - building_out_of_srctree := 1 endif ifneq ($(KBUILD_ABS_SRCTREE),) srctree := $(abs_srctree) endif -VPATH := +export srctree -ifeq ($(KBUILD_EXTMOD),) -ifdef building_out_of_srctree -VPATH := $(srctree) -endif -endif +_vpath = $(or $(abs_extmodtree),$(srctree)) -export building_out_of_srctree srctree VPATH +ifeq ($(realpath $(_vpath)),$(CURDIR)) +building_out_of_srctree := +VPATH := +else +export building_out_of_srctree := 1 +export VPATH := $(_vpath) +endif # To make sure we do not include .config for any of the *config targets # catch them early, and hand them over to scripts/kconfig/Makefile @@ -550,7 +558,7 @@ USERINCLUDE := \ LINUXINCLUDE := \ -I$(srctree)/arch/$(SRCARCH)/include \ -I$(objtree)/arch/$(SRCARCH)/include/generated \ - $(if $(building_out_of_srctree),-I$(srctree)/include) \ + -I$(srctree)/include \ -I$(objtree)/include \ $(USERINCLUDE) @@ -640,6 +648,7 @@ quiet_cmd_makefile = GEN Makefile } > Makefile outputmakefile: +ifeq ($(KBUILD_EXTMOD),) @if [ -f $(srctree)/.config -o \ -d $(srctree)/include/config -o \ -d $(srctree)/arch/$(SRCARCH)/include/generated ]; then \ @@ -649,7 +658,16 @@ outputmakefile: echo >&2 "***"; \ false; \ fi - $(Q)ln -fsn $(srctree) source +else + @if [ -f $(KBUILD_EXTMOD)/modules.order ]; then \ + echo >&2 "***"; \ + echo >&2 "*** The external module source tree is not clean."; \ + echo >&2 "*** Please run 'make -C $(abs_srctree) M=$(realpath $(KBUILD_EXTMOD)) clean'"; \ + echo >&2 "***"; \ + false; \ + fi +endif + $(Q)ln -fsn $(_vpath) source $(call cmd,makefile) $(Q)test -e .gitignore || \ { echo "# this is build directory, ignore it"; echo "*"; } > .gitignore @@ -1926,6 +1944,8 @@ KBUILD_MODULES := 1 endif +prepare: outputmakefile + # Preset locale variables to speed up the build process. Limit locale # tweaks to this spot to avoid wrong language settings when running # make menuconfig etc.
There has been a long-standing request to support building external modules in a separate build directory. This commit introduces a new environment variable, KBUILD_EXTMOD_OUTPUT, and its shorthand Make variable, MO. A simple usage: $ make -C <kernel-dir> M=<module-src-dir> MO=<module-build-dir> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> --- Documentation/kbuild/kbuild.rst | 8 +++++- Documentation/kbuild/modules.rst | 5 +++- Makefile | 44 +++++++++++++++++++++++--------- 3 files changed, 43 insertions(+), 14 deletions(-)