UAPI: Plumb the UAPI Kbuilds into the user header installation and checking

Plumb the UAPI Kbuilds into the user header installation and checking system.
As the headers are split the entries will be transferred across from the old
Kbuild files to the UAPI Kbuild files.

The changes made in this commit are:

 (1) Exported generated files (of which there are currently four) are moved to
     uapi/ directories under the appropriate generated/ directory, thus we
     get:

	include/generated/uapi/linux/version.h
	arch/x86/include/generated/uapi/asm/unistd_32.h
	arch/x86/include/generated/uapi/asm/unistd_64.h
	arch/x86/include/generated/uapi/asm/unistd_x32.h

     These paths were added to the build as -I flags in a previous patch.

 (2) scripts/Makefile.headersinst is now given the UAPI path to install from
     rather than the old path.

     It then determines the old path from that and includes that Kbuild also
     if it exists, thus permitting the headers to exist in either directory
     during the changeover.

     I also renamed the "install" variable to "installdir" as it refers to a
     directory not the install program.

 (3) scripts/headers_install.pl is altered to take a list of source file paths
     instead of just their names so that the makefile can tell it exactly
     where to find each file.

     For the moment, files can be obtained from one of four places for each
     output directory:

	.../include/uapi/foo/
	.../include/generated/uapi/foo/
	.../include/foo/
	.../include/generated/foo/

     The non-UAPI paths will be dropped later.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>

Makefile

@@ -447,7 +447,7 @@ asm-generic:
 # Detect when mixed targets is specified, and make a second invocation
 # of make so .config is not included in this case either (for *config).
 
-version_h := include/generated/linux/version.h
+version_h := include/generated/uapi/linux/version.h
 
 no-dot-config-targets := clean mrproper distclean \
 			 cscope gtags TAGS tags help %docs check% coccicheck \
@@ -908,10 +908,10 @@ headers_install_all:
 
 PHONY += headers_install
 headers_install: __headers
-	$(if $(wildcard $(srctree)/arch/$(hdr-arch)/include/asm/Kbuild),, \
+	$(if $(wildcard $(srctree)/arch/$(hdr-arch)/include/uapi/asm/Kbuild),, \
 	  $(error Headers not exportable for the $(SRCARCH) architecture))
-	$(Q)$(MAKE) $(hdr-inst)=include
-	$(Q)$(MAKE) $(hdr-inst)=arch/$(hdr-arch)/include/asm $(hdr-dst)
+	$(Q)$(MAKE) $(hdr-inst)=include/uapi
+	$(Q)$(MAKE) $(hdr-inst)=arch/$(hdr-arch)/include/uapi/asm $(hdr-dst)
 
 PHONY += headers_check_all
 headers_check_all: headers_install_all
@@ -919,8 +919,8 @@ headers_check_all: headers_install_all
 
 PHONY += headers_check
 headers_check: headers_install
-	$(Q)$(MAKE) $(hdr-inst)=include HDRCHECK=1
-	$(Q)$(MAKE) $(hdr-inst)=arch/$(hdr-arch)/include/asm $(hdr-dst) HDRCHECK=1
+	$(Q)$(MAKE) $(hdr-inst)=include/uapi HDRCHECK=1
+	$(Q)$(MAKE) $(hdr-inst)=arch/$(hdr-arch)/include/uapi/asm $(hdr-dst) HDRCHECK=1
 
 # ---------------------------------------------------------------------------
 # Modules

arch/x86/include/asm/Kbuild

@@ -22,7 +22,3 @@ header-y += sigcontext32.h
 header-y += ucontext.h
 header-y += vm86.h
 header-y += vsyscall.h
-
-genhdr-y += unistd_32.h
-genhdr-y += unistd_64.h
-genhdr-y += unistd_x32.h

arch/x86/syscalls/Makefile

 out := $(obj)/../include/generated/asm
-uapi := $(obj)/../include/generated/asm
+uapi := $(obj)/../include/generated/uapi/asm
 
 # Create output directory if not already present
 _dummy := $(shell [ -d '$(out)' ] || mkdir -p '$(out)') \

include/linux/Kbuild

@@ -20,8 +20,6 @@ header-y += netfilter_ipv6/
 header-y += usb/
 header-y += wimax/
 
-genhdr-y += version.h
-
 ifneq ($(wildcard $(srctree)/arch/$(SRCARCH)/include/asm/a.out.h \
 		  $(srctree)/include/asm-$(SRCARCH)/a.out.h \
 		  $(INSTALL_HDR_PATH)/include/asm-*/a.out.h),)

include/uapi/linux/Kbuild

@@ -20,3 +20,5 @@ header-y += netfilter_ipv4/
 header-y += netfilter_ipv6/
 header-y += usb/
 header-y += wimax/
+
+genhdr-y += version.h

scripts/Makefile.headersinst

@@ -8,7 +8,7 @@
 # ==========================================================================
 
 # called may set destination dir (when installing to asm/)
-_dst := $(if $(dst),$(dst),$(obj))
+_dst := $(or $(destination-y),$(dst),$(obj))
 
 # generated header directory
 gen := $(if $(gen),$(gen),$(subst include/,include/generated/,$(obj)))
@@ -16,47 +16,64 @@ gen := $(if $(gen),$(gen),$(subst include/,include/generated/,$(obj)))
 kbuild-file := $(srctree)/$(obj)/Kbuild
 include $(kbuild-file)
 
-_dst := $(if $(destination-y),$(destination-y),$(_dst))
+old-kbuild-file := $(srctree)/$(subst uapi/,,$(obj))/Kbuild
+ifneq ($(wildcard $(old-kbuild-file)),)
+include $(old-kbuild-file)
+endif
 
 include scripts/Kbuild.include
 
-install       := $(INSTALL_HDR_PATH)/$(_dst)
+installdir    := $(INSTALL_HDR_PATH)/$(subst uapi/,,$(_dst))
 
 header-y      := $(sort $(header-y))
 subdirs       := $(patsubst %/,%,$(filter %/, $(header-y)))
 header-y      := $(filter-out %/, $(header-y))
 
 # files used to track state of install/check
-install-file  := $(install)/.install
-check-file    := $(install)/.check
+install-file  := $(installdir)/.install
+check-file    := $(installdir)/.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))
 
+srcdir        := $(srctree)/$(obj)
+gendir        := $(objtree)/$(gen)
+
+oldsrcdir     := $(srctree)/$(subst /uapi,,$(obj))
+
 # all headers files for this dir
 header-y      := $(filter-out $(generic-y), $(header-y))
 all-files     := $(header-y) $(genhdr-y) $(wrapper-files)
-input-files   := $(addprefix $(srctree)/$(obj)/,$(header-y)) \
-                 $(addprefix $(objtree)/$(gen)/,$(genhdr-y))
-output-files  := $(addprefix $(install)/, $(all-files))
+output-files  := $(addprefix $(installdir)/, $(all-files))
+
+input-files   := $(foreach hdr, $(header-y), \
+		   $(or \
+			$(wildcard $(srcdir)/$(hdr)), \
+			$(wildcard $(oldsrcdir)/$(hdr)), \
+			$(error Missing UAPI file $(srcdir)/$(hdr)) \
+		   )) \
+		 $(foreach hdr, $(genhdr-y), \
+		   $(or \
+			$(wildcard $(gendir)/$(hdr)), \
+			$(error Missing generated UAPI file $(gendir)/$(hdr)) \
+		   ))
 
 # Work out what needs to be removed
-oldheaders    := $(patsubst $(install)/%,%,$(wildcard $(install)/*.h))
+oldheaders    := $(patsubst $(installdir)/%,%,$(wildcard $(installdir)/*.h))
 unwanted      := $(filter-out $(all-files),$(oldheaders))
 
 # Prefix unwanted with full paths to $(INSTALL_HDR_PATH)
-unwanted-file := $(addprefix $(install)/, $(unwanted))
+unwanted-file := $(addprefix $(installdir)/, $(unwanted))
 
 printdir = $(patsubst $(INSTALL_HDR_PATH)/%/,%,$(dir $@))
 
 quiet_cmd_install = INSTALL $(printdir) ($(words $(all-files))\
                             file$(if $(word 2, $(all-files)),s))
       cmd_install = \
-        $(PERL) $< $(srctree)/$(obj) $(install) $(SRCARCH) $(header-y); \
-        $(PERL) $< $(objtree)/$(gen) $(install) $(SRCARCH) $(genhdr-y); \
+        $(PERL) $< $(installdir) $(SRCARCH) $(input-files); \
         for F in $(wrapper-files); do                                   \
-                echo "\#include <asm-generic/$$F>" > $(install)/$$F;    \
+                echo "\#include <asm-generic/$$F>" > $(installdir)/$$F;    \
         done;                                                           \
         touch $@
 
@@ -67,7 +84,7 @@ quiet_cmd_check = CHECK   $(printdir) ($(words $(all-files)) files)
 # Headers list can be pretty long, xargs helps to avoid
 # the "Argument list too long" error.
       cmd_check = for f in $(all-files); do                          \
-                  echo "$(install)/$${f}"; done                      \
+                  echo "$(installdir)/$${f}"; done                      \
                   | xargs                                            \
                   $(PERL) $< $(INSTALL_HDR_PATH)/include $(SRCARCH); \
 	          touch $@

scripts/headers_install.pl

@@ -4,8 +4,7 @@
 # user space and copy the files to their destination.
 #
 # Usage: headers_install.pl readdir installdir arch [files...]
-# readdir:    dir to open files
-# installdir: dir to install the files
+# installdir: dir to install the files to
 # arch:       current architecture
 #             arch is used to force a reinstallation when the arch
 #             changes because kbuild then detect a command line change.
@@ -18,15 +17,18 @@
 
 use strict;
 
-my ($readdir, $installdir, $arch, @files) = @ARGV;
+my ($installdir, $arch, @files) = @ARGV;
 
 my $unifdef = "scripts/unifdef -U__KERNEL__ -D__EXPORTED_HEADERS__";
 
-foreach my $file (@files) {
+foreach my $filename (@files) {
+	my $file = $filename;
+	$file =~ s!^.*/!!;
+
 	my $tmpfile = "$installdir/$file.tmp";
 
-	open(my $in, '<', "$readdir/$file")
-	    or die "$readdir/$file: $!\n";
+	open(my $in, '<', $filename)
+	    or die "$filename: $!\n";
 	open(my $out, '>', $tmpfile)
 	    or die "$tmpfile: $!\n";
 	while (my $line = <$in>) {