uapi: export all headers under uapi directories

Regularly, when a new header is created in include/uapi/, the developer
forgets to add it in the corresponding Kbuild file. This error is usually
detected after the release is out.

In fact, all headers under uapi directories should be exported, thus it's
useless to have an exhaustive list.

After this patch, the following files, which were not exported, are now
exported (with make headers_install_all):
asm-arc/kvm_para.h
asm-arc/ucontext.h
asm-blackfin/shmparam.h
asm-blackfin/ucontext.h
asm-c6x/shmparam.h
asm-c6x/ucontext.h
asm-cris/kvm_para.h
asm-h8300/shmparam.h
asm-h8300/ucontext.h
asm-hexagon/shmparam.h
asm-m32r/kvm_para.h
asm-m68k/kvm_para.h
asm-m68k/shmparam.h
asm-metag/kvm_para.h
asm-metag/shmparam.h
asm-metag/ucontext.h
asm-mips/hwcap.h
asm-mips/reg.h
asm-mips/ucontext.h
asm-nios2/kvm_para.h
asm-nios2/ucontext.h
asm-openrisc/shmparam.h
asm-parisc/kvm_para.h
asm-powerpc/perf_regs.h
asm-sh/kvm_para.h
asm-sh/ucontext.h
asm-tile/shmparam.h
asm-unicore32/shmparam.h
asm-unicore32/ucontext.h
asm-x86/hwcap2.h
asm-xtensa/kvm_para.h
drm/armada_drm.h
drm/etnaviv_drm.h
drm/vgem_drm.h
linux/aspeed-lpc-ctrl.h
linux/auto_dev-ioctl.h
linux/bcache.h
linux/btrfs_tree.h
linux/can/vxcan.h
linux/cifs/cifs_mount.h
linux/coresight-stm.h
linux/cryptouser.h
linux/fsmap.h
linux/genwqe/genwqe_card.h
linux/hash_info.h
linux/kcm.h
linux/kcov.h
linux/kfd_ioctl.h
linux/lightnvm.h
linux/module.h
linux/nbd-netlink.h
linux/nilfs2_api.h
linux/nilfs2_ondisk.h
linux/nsfs.h
linux/pr.h
linux/qrtr.h
linux/rpmsg.h
linux/sched/types.h
linux/sed-opal.h
linux/smc.h
linux/smc_diag.h
linux/stm.h
linux/switchtec_ioctl.h
linux/vfio_ccw.h
linux/wil6210_uapi.h
rdma/bnxt_re-abi.h

Note that I have removed from this list the files which are generated in every
exported directories (like .install or .install.cmd).

Thanks to Julien Floret <julien.floret@6wind.com> for the tip to get all
subdirs with a pure makefile command.

For the record, note that exported files for asm directories are a mix of
files listed by:
 - include/uapi/asm-generic/Kbuild.asm;
 - arch/<arch>/include/uapi/asm/Kbuild;
 - arch/<arch>/include/asm/Kbuild.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Mark Salter <msalter@redhat.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

scripts/Makefile.headersinst

@@ -1,17 +1,19 @@
 # ==========================================================================
 # Installing headers
 #
-# header-y  - list files to be installed. They are preprocessed
-#             to remove __KERNEL__ section of the file
-# genhdr-y  - Same as header-y but in a generated/ directory
+# All headers under include/uapi, include/generated/uapi,
+# arch/<arch>/include/uapi/asm and arch/<arch>/include/generated/uapi/asm are
+# exported.
+# They are preprocessed to remove __KERNEL__ section of the file.
 #
 # ==========================================================================
 
 # generated header directory
 gen := $(if $(gen),$(gen),$(subst include/,include/generated/,$(obj)))
 
+# Kbuild file is optional
 kbuild-file := $(srctree)/$(obj)/Kbuild
-include $(kbuild-file)
+-include $(kbuild-file)
 
 # called may set destination dir (when installing to asm/)
 _dst := $(if $(dst),$(dst),$(obj))
@@ -25,9 +27,15 @@ include scripts/Kbuild.include
 
 installdir    := $(INSTALL_HDR_PATH)/$(subst uapi/,,$(_dst))
 
-header-y      := $(sort $(header-y))
-subdirs       := $(patsubst %/,%,$(filter %/, $(header-y)))
-header-y      := $(filter-out %/, $(header-y))
+srcdir        := $(srctree)/$(obj)
+gendir        := $(objtree)/$(gen)
+subdirs       := $(patsubst $(srcdir)/%/.,%,$(wildcard $(srcdir)/*/.))
+subdirs       += $(subdir-y)
+header-files  := $(notdir $(wildcard $(srcdir)/*.h))
+header-files  += $(notdir $(wildcard $(srcdir)/*.agh))
+header-files  := $(filter-out $(no-export-headers), $(header-files))
+genhdr-files  := $(notdir $(wildcard $(gendir)/*.h))
+genhdr-files  := $(filter-out $(header-files), $(genhdr-files))
 
 # files used to track state of install/check
 install-file  := $(installdir)/.install
@@ -35,25 +43,20 @@ 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)
+generic-files := $(notdir $(wildcard $(srctree)/include/uapi/asm-generic/*.h))
+wrapper-files := $(filter $(generic-files), $(generic-y))
+wrapper-files := $(filter-out $(header-files), $(wrapper-files))
 
 # all headers files for this dir
-header-y      := $(filter-out $(generic-y), $(header-y))
-all-files     := $(header-y) $(genhdr-y) $(wrapper-files)
+all-files     := $(header-files) $(genhdr-files) $(wrapper-files)
 output-files  := $(addprefix $(installdir)/, $(all-files))
 
-# Check that all expected files exist
-$(foreach hdr, $(header-y), \
-  $(if $(wildcard $(srcdir)/$(hdr)),, \
-       $(error Missing UAPI file $(srcdir)/$(hdr)) \
-   ))
-$(foreach hdr, $(genhdr-y), \
-  $(if	$(wildcard $(gendir)/$(hdr)),, \
-       $(error Missing generated UAPI file $(gendir)/$(hdr)) \
-  ))
+ifneq ($(mandatory-y),)
+missing       := $(filter-out $(all-files),$(mandatory-y))
+ifneq ($(missing),)
+$(error Some mandatory headers ($(missing)) are missing in $(obj))
+endif
+endif
 
 # Work out what needs to be removed
 oldheaders    := $(patsubst $(installdir)/%,%,$(wildcard $(installdir)/*.h))
@@ -67,8 +70,8 @@ printdir = $(patsubst $(INSTALL_HDR_PATH)/%/,%,$(dir $@))
 quiet_cmd_install = INSTALL $(printdir) ($(words $(all-files))\
                             file$(if $(word 2, $(all-files)),s))
       cmd_install = \
-        $(CONFIG_SHELL) $< $(installdir) $(srcdir) $(header-y); \
-        $(CONFIG_SHELL) $< $(installdir) $(gendir) $(genhdr-y); \
+        $(CONFIG_SHELL) $< $(installdir) $(srcdir) $(header-files); \
+        $(CONFIG_SHELL) $< $(installdir) $(gendir) $(genhdr-files); \
         for F in $(wrapper-files); do                                   \
                 echo "\#include <asm-generic/$$F>" > $(installdir)/$$F;    \
         done;                                                           \
@@ -95,8 +98,8 @@ __headersinst: $(subdirs) $(install-file)
 
 targets += $(install-file)
 $(install-file): scripts/headers_install.sh \
-		 $(addprefix $(srcdir)/,$(header-y)) \
-		 $(addprefix $(gendir)/,$(genhdr-y)) FORCE
+		 $(addprefix $(srcdir)/,$(header-files)) \
+		 $(addprefix $(gendir)/,$(genhdr-files)) FORCE
 	$(if $(unwanted),$(call cmd,remove),)
 	$(if $(wildcard $(dir $@)),,$(shell mkdir -p $(dir $@)))
 	$(call if_changed,install)