Commit 06300b21 authored by Sam Ravnborg's avatar Sam Ravnborg

kbuild: support building individual files for external modules

Support building individual files when dealing with separate modules.
So say you have a module named "foo" which consist of two .o files bar.o
and fun.o.

You can then do:
make -C $KERNELSRC M=`pwd` bar.o
make -C $KERNELSRC M=`pwd` bar.lst
make -C $KERNELSRC M=`pwd` bar.i
make -C $KERNELSRC M=`pwd` /            <= will build all .o files
                                           and link foo.o
make -C $KERNELSRC M=`pwd` foo.ko       <= will build the module
                                           and do the modpost step
					   to create foo.ko

The above will also work if the external module is placed in a
subdirectory using a hirachy of kbuild files.
Thanks to Andreas Gruenbacher <agruen@suse.de> for initial feature
request / bug report.
Signed-off-by: default avatarSam Ravnborg <sam@ravnborg.org>
parent bd71c2b1
......@@ -13,6 +13,7 @@ In this document you will find information about:
--- 2.2 Available targets
--- 2.3 Available options
--- 2.4 Preparing the kernel tree for module build
--- 2.5 Building separate files for a module
=== 3. Example commands
=== 4. Creating a kbuild file for an external module
=== 5. Include files
......@@ -131,6 +132,16 @@ when building an external module.
Therefore a full kernel build needs to be executed to make
module versioning work.
--- 2.5 Building separate files for a module
It is possible to build single files which is part of a module.
This works equal for the kernel, a module and even for external
modules.
Examples (module foo.ko, consist of bar.o, baz.o):
make -C $KDIR M=`pwd` bar.lst
make -C $KDIR M=`pwd` bar.o
make -C $KDIR M=`pwd` foo.ko
make -C $KDIR M=`pwd` /
=== 3. Example commands
......
......@@ -137,7 +137,7 @@ objtree := $(CURDIR)
src := $(srctree)
obj := $(objtree)
VPATH := $(srctree)
VPATH := $(srctree):$(KBUILD_EXTMOD)
export srctree objtree VPATH TOPDIR
......@@ -849,27 +849,6 @@ prepare prepare-all: prepare0
export CPPFLAGS_vmlinux.lds += -P -C -U$(ARCH)
# Single targets
# ---------------------------------------------------------------------------
%.s: %.c scripts FORCE
$(Q)$(MAKE) $(build)=$(@D) $@
%.i: %.c scripts FORCE
$(Q)$(MAKE) $(build)=$(@D) $@
%.o: %.c scripts FORCE
$(Q)$(MAKE) $(build)=$(@D) $@
%.ko: scripts FORCE
$(Q)$(MAKE) KBUILD_MODULES=$(if $(CONFIG_MODULES),1) $(build)=$(@D) $(@:.ko=.o)
$(Q)$(MAKE) -rR -f $(srctree)/scripts/Makefile.modpost
%/: scripts prepare FORCE
$(Q)$(MAKE) KBUILD_MODULES=$(if $(CONFIG_MODULES),1) $(build)=$(@D)
%.lst: %.c scripts FORCE
$(Q)$(MAKE) $(build)=$(@D) $@
%.s: %.S scripts FORCE
$(Q)$(MAKE) $(build)=$(@D) $@
%.o: %.S scripts FORCE
$(Q)$(MAKE) $(build)=$(@D) $@
# FIXME: The asm symlink changes when $(ARCH) changes. That's
# hard to detect, but I suppose "make mrproper" is a good idea
# before switching between archs anyway.
......@@ -1192,6 +1171,11 @@ help:
@echo ' modules_install - install the module'
@echo ' clean - remove generated files in module directory only'
@echo ''
# Dummies...
.PHONY: prepare scripts
prepare: ;
scripts: ;
endif # KBUILD_EXTMOD
# Generate tags for editors
......@@ -1313,6 +1297,44 @@ kernelrelease:
kernelversion:
@echo $(KERNELVERSION)
# Single targets
# ---------------------------------------------------------------------------
# The directory part is taken from first prerequisite, so this
# works even with external modules
%.s: %.c scripts FORCE
$(Q)$(MAKE) $(build)=$(dir $<) $(dir $<)$(notdir $@)
%.i: %.c scripts FORCE
$(Q)$(MAKE) $(build)=$(dir $<) $(dir $<)$(notdir $@)
%.o: %.c scripts FORCE
$(Q)$(MAKE) $(build)=$(dir $<) $(dir $<)$(notdir $@)
%.lst: %.c scripts FORCE
$(Q)$(MAKE) $(build)=$(dir $<) $(dir $<)$(notdir $@)
%.s: %.S scripts FORCE
$(Q)$(MAKE) $(build)=$(dir $<) $(dir $<)$(notdir $@)
%.o: %.S scripts FORCE
$(Q)$(MAKE) $(build)=$(dir $<) $(dir $<)$(notdir $@)
# For external modules we shall include any directory of the target,
# but usual case there is no directory part.
# make M=`pwd` module.o => $(dir $@)=./
# make M=`pwd` foo/module.o => $(dir $@)=foo/
# make M=`pwd` / => $(dir $@)=/
ifeq ($(KBUILD_EXTMOD),)
target-dir = $(@D)
else
zap-slash=$(filter-out .,$(patsubst %/,%,$(dir $@)))
target-dir = $(KBUILD_EXTMOD)$(if $(zap-slash),/$(zap-slash))
endif
/ %/: scripts prepare FORCE
$(Q)$(MAKE) KBUILD_MODULES=$(if $(CONFIG_MODULES),1) \
$(build)=$(target-dir)
%.ko: scripts FORCE
$(Q)$(MAKE) KBUILD_MODULES=$(if $(CONFIG_MODULES),1) \
$(build)=$(target-dir) $(@:.ko=.o)
$(Q)$(MAKE) -rR -f $(srctree)/scripts/Makefile.modpost
# FIXME Should go into a make.lib or something
# ===========================================================================
......
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