RE: [PATCH v3] kbuild: asm-generic support

[Guan Xuetao]

> -----Original Message-----
> From: Sam Ravnborg [mailto:sam@xxxxxxxxxxxx]
> Sent: Friday, April 22, 2011 11:54 PM
> To: Michal Marek
> Cc: lkml; linux-kbuild; linux arch; Arnd Bergmann; Guan Xuetao
> Subject: [PATCH v3] kbuild: asm-generic support
> 
> >From 34d0b72a343dd63c1c1b049e4ba6931f0dbcbc3f Mon Sep 17 00:00:00 2001
> From: Sam Ravnborg <sam@xxxxxxxxxxxx>
> Date: Fri, 22 Apr 2011 14:45:13 +0200
> Subject: [PATCH] kbuild: asm-generic support
> 
> There is an increasing amount of header files
> shared between individual architectures in asm-generic.
> To avoid a lot of dummy wrapper files that just
> include the corresponding file in asm-generic provide
> some basic support in kbuild for this.
> 
> With the following patch an architecture can maintain
> a list of files in the file arch/$(ARCH)/include/asm/Kbuild
> 
> To use a generic file just add:
> 
>         generic-y += <name-of-header-file.h>
> 
> For each file listed kbuild will generate the necessary
> wrapper in arch/$(ARCH)/include/generated/asm.
> 
> When installing userspace headers a wrapper is likewise created.
> 
> The original inspiration for this came from the unicore32
> patchset - although a different method is used.
> 
> The patch includes several improvements from Arnd Bergmann.
> Michael Marek contributed Makefile.asm-generic.
> 
> Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
> Cc: Guan Xuetao <guanxuetao@xxxxxxxxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> ---
> 
> Hi Mikael.
> 
> It took me a while to get back to this.
> I used your Makefile.asm-generic almost verbatim.
> 
> Only change was that we always need to create the output directory.
> 
> 	Sam
> 
>  .gitignore                         |    1 +
>  Documentation/kbuild/makefiles.txt |   36 ++++++++++++++++++++++++++++++++++++
>  Makefile                           |   15 +++++++++++----
>  scripts/Makefile.asm-generic       |   23 +++++++++++++++++++++++
>  scripts/Makefile.headersinst       |   18 +++++++++++++++---
>  5 files changed, 86 insertions(+), 7 deletions(-)
>  create mode 100644 scripts/Makefile.asm-generic
> 
> diff --git a/.gitignore b/.gitignore
> index 5d56a3f..9dacde0 100644
> --- a/.gitignore
> +++ b/.gitignore
> @@ -57,6 +57,7 @@ modules.builtin
>  include/config
>  include/linux/version.h
>  include/generated
> +arch/*/include/generated
> 
>  # stgit generated dirs
>  patches-*
> diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
> index 5d145bb..7f2b8e7 100644
> --- a/Documentation/kbuild/makefiles.txt
> +++ b/Documentation/kbuild/makefiles.txt
> @@ -40,11 +40,13 @@ This document describes the Linux kernel Makefiles.
>  	   --- 6.6 Commands useful for building a boot image
>  	   --- 6.7 Custom kbuild commands
>  	   --- 6.8 Preprocessing linker scripts
> +	   --- 6.9 Generic header files
> 
>  	=== 7 Kbuild syntax for exported headers
>  		--- 7.1 header-y
>  		--- 7.2 objhdr-y
>  		--- 7.3 destination-y
> +		--- 7.4 generic-y
> 
>  	=== 8 Kbuild Variables
>  	=== 9 Makefile language
> @@ -1209,6 +1211,14 @@ When kbuild executes, the following steps are followed (roughly):
>  	The kbuild infrastructure for *lds file are used in several
>  	architecture-specific files.
> 
> +--- 6.9 Generic header files
> +
> +	The directory include/asm-generic contains the header files
> +	that may be shared between individual architectures.
> +	The recommended approach how to use a generic header file is
> +	to list the file in the Kbuild file.
> +	See "7.4 generic-y" for further info on syntax etc.
> +
>  === 7 Kbuild syntax for exported headers
> 
>  The kernel include a set of headers that is exported to userspace.
> @@ -1265,6 +1275,32 @@ See subsequent chapter for the syntax of the Kbuild file.
>  	In the example above all exported headers in the Kbuild file
>  	will be located in the directory "include/linux" when exported.
> 
> +	--- 7.4 generic-y
> +
> +	If an architecture uses a verbatim copy of a header from
> +	include/asm-generic then this is listed in the file
> +	arch/$(ARCH)/include/asm/Kbuild like this:
> +
> +		Example:
> +			#arch/x86/include/asm/Kbuild
> +			generic-y += termios.h
> +			generic-y += rtc.h
> +
> +	During the prepare phase of the build a wrapper include
> +	file is generated in the directory:
> +
> +		arch/$(ARCH)/include/generated/asm
> +
> +	When a header is exported where the architecture uses
> +	the generic header a similar wrapper is generated as part
> +	of the set of exported headers in the directory:
> +
> +		usr/include/asm
> +
> +	The generated wrapper will in both cases look like the following:
> +
> +		Example: termios.h
> +			#include <asm-generic/termios.h>
> 
>  === 8 Kbuild Variables
> 
> diff --git a/Makefile b/Makefile
> index b967b96..30b3852 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -349,7 +349,8 @@ CFLAGS_GCOV	= -fprofile-arcs -ftest-coverage
> 
>  # Use LINUXINCLUDE when you must reference the include/ directory.
>  # Needed to be compatible with the O= option
> -LINUXINCLUDE    := -I$(srctree)/arch/$(hdr-arch)/include -Iinclude \
> +LINUXINCLUDE    := -I$(srctree)/arch/$(hdr-arch)/include \
> +                   -Iarch/$(hdr-arch)/include/generated -Iinclude \
I think $(srctree) is necessary before new include-dir.

>                     $(if $(KBUILD_SRC), -I$(srctree)/include) \
>                     -include include/generated/autoconf.h
> 
> @@ -416,6 +417,11 @@ ifneq ($(KBUILD_SRC),)
>  	    $(srctree) $(objtree) $(VERSION) $(PATCHLEVEL)
>  endif
> 
> +# Support for using generic headers in asm-generic
> +PHONY += asm-generic
> +asm-generic:
> +	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.asm-generic obj=arch/$(SRCARCH)/include/generated/asm
Too long

> +
>  # 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
>  # It is allowed to specify more targets when calling make, including
> @@ -947,7 +953,7 @@ ifneq ($(KBUILD_SRC),)
>  endif
> 
>  # prepare2 creates a makefile if using a separate output directory
> -prepare2: prepare3 outputmakefile
> +prepare2: prepare3 outputmakefile asm-generic
> 
>  prepare1: prepare2 include/linux/version.h include/generated/utsrelease.h \
>                     include/config/auto.conf
> @@ -1021,7 +1027,7 @@ hdr-inst := -rR -f $(srctree)/scripts/Makefile.headersinst obj
>  hdr-dst = $(if $(KBUILD_HEADERS), dst=include/asm-$(hdr-arch), dst=include/asm)
> 
>  PHONY += __headers
> -__headers: include/linux/version.h scripts_basic FORCE
> +__headers: include/linux/version.h scripts_basic asm-generic FORCE
>  	$(Q)$(MAKE) $(build)=scripts build_unifdef
> 
>  PHONY += headers_install_all
> @@ -1136,7 +1142,8 @@ CLEAN_FILES +=	vmlinux System.map \
>                  .tmp_kallsyms* .tmp_version .tmp_vmlinux* .tmp_System.map
> 
>  # Directories & files removed with 'make mrproper'
> -MRPROPER_DIRS  += include/config usr/include include/generated
> +MRPROPER_DIRS  += include/config usr/include include/generated          \
> +                  arch/*/include/generated
>  MRPROPER_FILES += .config .config.old .version .old_version             \
>                    include/linux/version.h                               \
>  		  Module.symvers tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS
> diff --git a/scripts/Makefile.asm-generic b/scripts/Makefile.asm-generic
> new file mode 100644
> index 0000000..a687cb6
> --- /dev/null
> +++ b/scripts/Makefile.asm-generic
> @@ -0,0 +1,23 @@
> +# include/asm-generic contains a lot of files that are used
> +# verbatim by several architectures.
> +#
> +# This Makefile reads the file arch/$(SRCARCH)/include/asm/Kbuild
> +# and for each file listed in this file with generic-y creates
> +# a small wrapper file in $(obj) (arch/$(SRCARCH)/include/generated/asm)
> +
> +kbuild-file := $(srctree)/arch/$(SRCARCH)/include/asm/Kbuild
> +include $(kbuild-file)
> +
> +include scripts/Kbuild.include
> +
> +# Create output directory if not already present
> +_dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
> +
> +quiet_cmd_wrap = WRAP    $@
> +cmd_wrap = echo "\#include <asm-generic/$*.h>" >$@
> +
> +all: $(patsubst %, $(obj)/%, $(generic-y))
> +
> +$(obj)/%.h:
> +	$(call cmd,wrap)
> +
> diff --git a/scripts/Makefile.headersinst b/scripts/Makefile.headersinst
> index f89cb87..7960b19 100644
> --- a/scripts/Makefile.headersinst
> +++ b/scripts/Makefile.headersinst
> @@ -14,6 +14,7 @@ kbuild-file := $(srctree)/$(obj)/Kbuild
>  include $(kbuild-file)
> 
>  _dst := $(if $(destination-y),$(destination-y),$(_dst))
> +_src := $(srctree)/$(obj)
_src is only used one time

> 
>  include scripts/Kbuild.include
> 
> @@ -27,10 +28,16 @@ header-y      := $(filter-out %/, $(header-y))
>  install-file  := $(install)/.install
>  check-file    := $(install)/.check
> 
> +# generic-y list all files an architecture uses from asm-generic
> +# Use this to build a list of headers which require a wrapper
> +wrapper-files := $(filter $(header-y), $(generic-y))
> +
>  # all headers files for this dir
> -all-files     := $(header-y) $(objhdr-y)
> -input-files   := $(addprefix $(srctree)/$(obj)/,$(header-y)) \
> +header-y      := $(filter-out $(generic-y), $(header-y))
> +all-files     := $(header-y) $(objhdr-y) $(wrapper-files)
> +input-files   := $(addprefix $(_src)/,$(header-y)) \
>                   $(addprefix $(objtree)/$(obj)/,$(objhdr-y))
> +
Additional empty line

>  output-files  := $(addprefix $(install)/, $(all-files))
> 
>  # Work out what needs to be removed
> @@ -47,8 +54,12 @@ quiet_cmd_install = INSTALL $(printdir) ($(words $(all-files))\
>        cmd_install = \
>          $(PERL) $< $(srctree)/$(obj) $(install) $(SRCARCH) $(header-y); \
>          $(PERL) $< $(objtree)/$(obj) $(install) $(SRCARCH) $(objhdr-y); \
> +        for F in $(wrapper-files); do                                   \
> +                echo "\#include <asm-generic/$$F>" > $(install)/$$F;    \
> +        done;                                                           \
>          touch $@
> 
> +
Additional empty line

>  quiet_cmd_remove = REMOVE  $(unwanted)
>        cmd_remove = rm -f $(unwanted-file)
> 
> @@ -69,7 +80,8 @@ __headersinst: $(subdirs) $(install-file)
>  	@:
> 
>  targets += $(install-file)
> -$(install-file): scripts/headers_install.pl $(input-files) FORCE
> +$(install-file): scripts/headers_install.pl \
> +                 $(input-files) FORCE
The same content

>  	$(if $(unwanted),$(call cmd,remove),)
>  	$(if $(wildcard $(dir $@)),,$(shell mkdir -p $(dir $@)))
>  	$(call if_changed,install)
> --
> 1.6.0.6

I have tested on UniCore32, and it works well.

Thanks Sam.

Guan Xuetao

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