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Commit 59b2bd05 authored by Masahiro Yamada's avatar Masahiro Yamada
Browse files

kbuild: add 'headers' target to build up uapi headers in usr/include 



In Linux build system, build targets and installation targets are
separated.

Examples are:

 - 'make vmlinux' -> 'make install'
 - 'make modules' -> 'make modules_install'
 - 'make dtbs'    -> 'make dtbs_install'
 - 'make vdso'    -> 'make vdso_install'

The intention is to run the build targets under the normal privilege,
then the installation targets under the root privilege since we need
the write permission to the system directories.

We have 'make headers_install' but the corresponding 'make headers'
stage does not exist. The purpose of headers_install is to provide
the kernel interface to C library. So, nobody would try to install
headers to /usr/include directly.

If 'sudo make INSTALL_HDR_PATH=/usr/include headers_install' were run,
some build artifacts in the kernel tree would be owned by root because
some of uapi headers are generated by 'uapi-asm-generic', 'archheaders'
targets.

Anyway, I believe it makes sense to split the header installation into
two stages.

 [1] 'make headers'
    Process headers in uapi directories by scripts/headers_install.sh
    and copy them to usr/include

 [2] 'make headers_install'
    Copy '*.h' verbatim from usr/include to $(INSTALL_HDR_PATH)/include

For the backward compatibility, 'headers_install' depends on 'headers'.

Some samples expect uapi headers in usr/include. So, the 'headers'
target is useful to build up them in the fixed location usr/include
irrespective of INSTALL_HDR_PATH.

Another benefit is to stop polluting the final destination with the
time-stamp files '.install' and '.check'. Maybe you can see them in
your toolchains.

Lastly, my main motivation is to prepare for compile-testing uapi
headers. To build something, we have to save an object and .*.cmd
somewhere. The usr/include/ will be the work directory for that.

Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
parent bdd7714b

Makefile

+15 −8
Original line number Diff line number Diff line
@@ -262,7 +262,7 @@ old_version_h := include/linux/version.h 
clean-targets := %clean mrproper cleandocs

no-dot-config-targets := $(clean-targets) \

			 cscope gtags TAGS tags help% %docs check% coccicheck \

			 $(version_h) headers_% archheaders archscripts \

			 $(version_h) headers headers_% archheaders archscripts \

			 %asm-generic kernelversion %src-pkg

no-sync-config-targets := $(no-dot-config-targets) install %install \

			   kernelrelease
@@ -1178,25 +1178,32 @@ headerdep: 
#Default location for installed headers

export INSTALL_HDR_PATH = $(objtree)/usr



PHONY += archheaders archscripts



PHONY += __headers

__headers: $(version_h) scripts_unifdef uapi-asm-generic archheaders archscripts

quiet_cmd_headers_install = INSTALL $(INSTALL_HDR_PATH)/include

      cmd_headers_install = \

	mkdir -p $(INSTALL_HDR_PATH); \

	rsync -mrl --include='*/' --include='*\.h' --exclude='*' \

	usr/include $(INSTALL_HDR_PATH)



PHONY += headers_install

headers_install: __headers

headers_install: headers

	$(call cmd,headers_install)



PHONY += archheaders archscripts



PHONY += headers

headers: $(version_h) scripts_unifdef uapi-asm-generic archheaders archscripts

	$(if $(wildcard $(srctree)/arch/$(SRCARCH)/include/uapi/asm/Kbuild),, \

	  $(error Headers not exportable for the $(SRCARCH) architecture))

	$(Q)$(MAKE) $(hdr-inst)=include/uapi dst=include

	$(Q)$(MAKE) $(hdr-inst)=arch/$(SRCARCH)/include/uapi dst=include



PHONY += headers_check

headers_check: headers_install

headers_check: headers

	$(Q)$(MAKE) $(hdr-inst)=include/uapi dst=include HDRCHECK=1

	$(Q)$(MAKE) $(hdr-inst)=arch/$(SRCARCH)/include/uapi dst=include HDRCHECK=1



ifdef CONFIG_HEADERS_INSTALL

prepare: headers_install

prepare: headers

endif



ifdef CONFIG_HEADERS_CHECK

lib/Kconfig.debug

+1 −3
Original line number Diff line number Diff line
@@ -324,9 +324,7 @@ config HEADERS_CHECK 
	  attempt to include files which were not exported, etc.



	  If you're making modifications to header files which are

	  relevant for userspace, say 'Y', and check the headers

	  exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in

	  your build tree), to make sure they're suitable.

	  relevant for userspace, say 'Y'.



config OPTIMIZE_INLINING

	bool "Allow compiler to uninline functions marked 'inline'"

scripts/Makefile.headersinst

+4 −4
Original line number Diff line number Diff line
@@ -41,7 +41,7 @@ ifeq ($(skip-inst),) 
kbuild-file := $(srctree)/$(obj)/Kbuild

-include $(kbuild-file)



installdir    := $(INSTALL_HDR_PATH)/$(dst)

installdir    := usr/$(dst)

gendir        := $(objtree)/$(subst include/,include/generated/,$(obj))

header-files  := $(notdir $(wildcard $(srcdir)/*.h))

header-files  := $(filter-out $(no-export-headers), $(header-files))
@@ -60,10 +60,10 @@ output-files := $(addprefix $(installdir)/, $(all-files)) 
oldheaders    := $(patsubst $(installdir)/%,%,$(wildcard $(installdir)/*.h))

unwanted      := $(filter-out $(all-files),$(oldheaders))



# Prefix unwanted with full paths to $(INSTALL_HDR_PATH)

# Prefix unwanted with full paths to objtree

unwanted-file := $(addprefix $(installdir)/, $(unwanted))



printdir = $(patsubst $(INSTALL_HDR_PATH)/%/,%,$(dir $@))

printdir = $(patsubst %/,%,$(dir $@))



quiet_cmd_install = INSTALL $(printdir) ($(words $(all-files))\

                            file$(if $(word 2, $(all-files)),s))
@@ -81,7 +81,7 @@ quiet_cmd_check = CHECK $(printdir) ($(words $(all-files)) files) 
      cmd_check = for f in $(all-files); do                          \

                  echo "$(installdir)/$${f}"; done                      \

                  | xargs                                            \

                  $(PERL) $< $(INSTALL_HDR_PATH)/include $(SRCARCH); \

                  $(PERL) $< usr/include $(SRCARCH); \

	          touch $@



ifndef HDRCHECK