Merge tag 'kbuild-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - remove headers_{install,check}_all targets

 - remove unreasonable 'depends on !UML' from CONFIG_SAMPLES

 - re-implement 'make headers_install' more cleanly

 - add new header-test-y syntax to compile-test headers

 - compile-test exported headers to ensure they are compilable in
   user-space

 - compile-test headers under include/ to ensure they are self-contained

 - remove -Waggregate-return, -Wno-uninitialized, -Wno-unused-value
   flags

 - add -Werror=unknown-warning-option for Clang

 - add 128-bit built-in types support to genksyms

 - fix missed rebuild of modules.builtin

 - propagate 'No space left on device' error in fixdep to Make

 - allow Clang to use its integrated assembler

 - improve some coccinelle scripts

 - add a new flag KBUILD_ABS_SRCTREE to request Kbuild to use absolute
   path for $(srctree).

 - do not ignore errors when compression utility is missing

 - misc cleanups

* tag 'kbuild-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (49 commits)
  kbuild: use -- separater intead of $(filter-out ...) for cc-cross-prefix
  kbuild: Inform user to pass ARCH= for make mrproper
  kbuild: fix compression errors getting ignored
  kbuild: add a flag to force absolute path for srctree
  kbuild: replace KBUILD_SRCTREE with boolean building_out_of_srctree
  kbuild: remove src and obj from the top Makefile
  scripts/tags.sh: remove unused environment variables from comments
  scripts/tags.sh: drop SUBARCH support for ARM
  kbuild: compile-test kernel headers to ensure they are self-contained
  kheaders: include only headers into kheaders_data.tar.xz
  kheaders: remove meaningless -R option of 'ls'
  kbuild: support header-test-pattern-y
  kbuild: do not create wrappers for header-test-y
  kbuild: compile-test exported headers to ensure they are self-contained
  init/Kconfig: add CONFIG_CC_CAN_LINK
  kallsyms: exclude kasan local symbols on s390
  kbuild: add more hints about SUBDIRS replacement
  coccinelle: api/stream_open: treat all wait_.*() calls as blocking
  coccinelle: put_device: Add a cast to an expression for an assignment
  coccinelle: put_device: Adjust a message construction
  ...

Documentation/kbuild/headers_install.rst

@@ -40,12 +40,5 @@ INSTALL_HDR_PATH indicates where to install the headers. It defaults to
 An 'include' directory is automatically created inside INSTALL_HDR_PATH and
 headers are installed in 'INSTALL_HDR_PATH/include'.
 
-The command "make headers_install_all" exports headers for all architectures
-simultaneously.  (This is mostly of interest to distribution maintainers,
-who create an architecture-independent tarball from the resulting include
-directory.)  You also can use HDR_ARCH_LIST to specify list of architectures.
-Remember to provide the appropriate linux/asm directory via "mv" or "ln -s"
-before building a C library with headers exported this way.
-
 The kernel header export infrastructure is maintained by David Woodhouse
 <dwmw2@infradead.org>.

Documentation/kbuild/kbuild.rst

@@ -200,6 +200,15 @@ The output directory is often set using "O=..." on the commandline.
 
 The value can be overridden in which case the default value is ignored.
 
+KBUILD_ABS_SRCTREE
+--------------------------------------------------
+Kbuild uses a relative path to point to the tree when possible. For instance,
+when building in the source tree, the source tree path is '.'
+
+Setting this flag requests Kbuild to use absolute path to the source tree.
+There are some useful cases to do so, like when generating tag files with
+absolute path entries etc.
+
 KBUILD_SIGN_PIN
 ---------------
 This variable allows a passphrase or PIN to be passed to the sign-file

Documentation/kbuild/makefiles.rst

@@ -999,11 +999,7 @@ When kbuild executes, the following steps are followed (roughly):
 ------------------------------------
 
 	The archheaders: rule is used to generate header files that
-	may be installed into user space by "make header_install" or
-	"make headers_install_all".  In order to support
-	"make headers_install_all", this target has to be able to run
-	on an unconfigured tree, or a tree configured for another
-	architecture.
+	may be installed into user space by "make header_install".
 
 	It is run before "make archprepare" when run on the
 	architecture itself.
@@ -1140,6 +1136,22 @@ When kbuild executes, the following steps are followed (roughly):
 	In this example, extra-y is used to list object files that
 	shall be built, but shall not be linked as part of built-in.a.
 
+    header-test-y
+
+	header-test-y specifies headers (*.h) in the current directory that
+	should be compile tested to ensure they are self-contained,
+	i.e. compilable as standalone units. If CONFIG_HEADER_TEST is enabled,
+	this builds them as part of extra-y.
+
+    header-test-pattern-y
+
+	This works as a weaker version of header-test-y, and accepts wildcard
+	patterns. The typical usage is:
+
+		  header-test-pattern-y += *.h
+
+	This specifies all the files that matches to '*.h' in the current
+	directory, but the files in 'header-test-' are excluded.
 
 6.7 Commands useful for building a boot image
 ---------------------------------------------

Makefile

@@ -212,6 +212,13 @@ endif
 ifdef SUBDIRS
   $(warning ================= WARNING ================)
   $(warning 'SUBDIRS' will be removed after Linux 5.3)
+  $(warning )
+  $(warning If you are building an individual subdirectory)
+  $(warning in the kernel tree, you can do like this:)
+  $(warning $$ make path/to/dir/you/want/to/build/)
+  $(warning (Do not forget the trailing slash))
+  $(warning )
+  $(warning If you are building an external module,)
   $(warning Please use 'M=' or 'KBUILD_EXTMOD' instead)
   $(warning ==========================================)
   KBUILD_EXTMOD ?= $(SUBDIRS)
@@ -221,9 +228,12 @@ ifeq ("$(origin M)", "command line")
   KBUILD_EXTMOD := $(M)
 endif
 
+export KBUILD_CHECKSRC KBUILD_EXTMOD
+
 ifeq ($(abs_srctree),$(abs_objtree))
         # building in the source tree
         srctree := .
+	building_out_of_srctree :=
 else
         ifeq ($(abs_srctree)/,$(dir $(abs_objtree)))
                 # building in a subdirectory of the source tree
@@ -231,22 +241,17 @@ else
         else
                 srctree := $(abs_srctree)
         endif
-
-	# TODO:
-	# KBUILD_SRC is only used to distinguish in-tree/out-of-tree build.
-	# Replace it with $(srctree) or something.
-	KBUILD_SRC := $(abs_srctree)
+	building_out_of_srctree := 1
 endif
 
-export KBUILD_CHECKSRC KBUILD_EXTMOD KBUILD_SRC
+ifneq ($(KBUILD_ABS_SRCTREE),)
+srctree := $(abs_srctree)
+endif
 
 objtree		:= .
-src		:= $(srctree)
-obj		:= $(objtree)
-
 VPATH		:= $(srctree)
 
-export srctree objtree VPATH
+export building_out_of_srctree srctree objtree VPATH
 
 # 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
@@ -262,7 +267,7 @@ 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 := $(no-dot-config-targets) install %install \
 			   kernelrelease
@@ -449,7 +454,7 @@ USERINCLUDE    := \
 LINUXINCLUDE    := \
 		-I$(srctree)/arch/$(SRCARCH)/include \
 		-I$(objtree)/arch/$(SRCARCH)/include/generated \
-		$(if $(filter .,$(srctree)),,-I$(srctree)/include) \
+		$(if $(building_out_of_srctree),-I$(srctree)/include) \
 		-I$(objtree)/include \
 		$(USERINCLUDE)
 
@@ -510,7 +515,7 @@ PHONY += outputmakefile
 # At the same time when output Makefile generated, generate .gitignore to
 # ignore whole output directory
 outputmakefile:
-ifneq ($(srctree),.)
+ifdef building_out_of_srctree
 	$(Q)ln -fsn $(srctree) source
 	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile $(srctree)
 	$(Q)test -e .gitignore || \
@@ -527,7 +532,10 @@ endif
 ifneq ($(GCC_TOOLCHAIN),)
 CLANG_FLAGS	+= --gcc-toolchain=$(GCC_TOOLCHAIN)
 endif
+ifeq ($(shell $(AS) --version 2>&1 | head -n 1 | grep clang),)
 CLANG_FLAGS	+= -no-integrated-as
+endif
+CLANG_FLAGS	+= -Werror=unknown-warning-option
 KBUILD_CFLAGS	+= $(CLANG_FLAGS)
 KBUILD_AFLAGS	+= $(CLANG_FLAGS)
 export CLANG_FLAGS
@@ -608,6 +616,7 @@ ifeq ($(KBUILD_EXTMOD),)
 init-y		:= init/
 drivers-y	:= drivers/ sound/
 drivers-$(CONFIG_SAMPLES) += samples/
+drivers-$(CONFIG_KERNEL_HEADER_TEST) += include/
 net-y		:= net/
 libs-y		:= lib/
 core-y		:= usr/
@@ -1053,9 +1062,6 @@ vmlinux: scripts/link-vmlinux.sh autoksyms_recursive $(vmlinux-deps) FORCE
 
 targets := vmlinux
 
-# Some samples need headers_install.
-samples: headers_install
-
 # The actual objects are generated when descending,
 # make sure no implicit rule kicks in
 $(sort $(vmlinux-deps)): $(vmlinux-dirs) ;
@@ -1096,12 +1102,12 @@ PHONY += prepare archprepare prepare1 prepare3
 # and if so do:
 # 1) Check that make has not been executed in the kernel src $(srctree)
 prepare3: include/config/kernel.release
-ifneq ($(srctree),.)
+ifdef building_out_of_srctree
 	@$(kecho) '  Using $(srctree) as source for kernel'
 	$(Q)if [ -f $(srctree)/.config -o \
 		 -d $(srctree)/include/config -o \
 		 -d $(srctree)/arch/$(SRCARCH)/include/generated ]; then \
-		echo >&2 "  $(srctree) is not clean, please run 'make mrproper'"; \
+		echo >&2 "  $(srctree) is not clean, please run 'make ARCH=$(ARCH) mrproper'"; \
 		echo >&2 "  in the '$(srctree)' directory.";\
 		/bin/false; \
 	fi;
@@ -1181,39 +1187,44 @@ headerdep:
 #Default location for installed headers
 export INSTALL_HDR_PATH = $(objtree)/usr
 
-# If we do an all arch process set dst to include/arch-$(SRCARCH)
-hdr-dst = $(if $(KBUILD_HEADERS), dst=include/arch-$(SRCARCH), dst=include)
+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 += archheaders archscripts
+PHONY += headers_install
+headers_install: headers
+	$(call cmd,headers_install)
 
-PHONY += __headers
-__headers: $(version_h) scripts_basic uapi-asm-generic archheaders archscripts
-	$(Q)$(MAKE) $(build)=scripts build_unifdef
+PHONY += archheaders archscripts
 
-PHONY += headers_install_all
-headers_install_all:
-	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/headers.sh install
+hdr-inst := -f $(srctree)/scripts/Makefile.headersinst obj
 
-PHONY += headers_install
-headers_install: __headers
+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 $(hdr-dst)
-
-PHONY += headers_check_all
-headers_check_all: headers_install_all
-	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/headers.sh check
+	$(Q)$(MAKE) $(hdr-inst)=include/uapi
+	$(Q)$(MAKE) $(hdr-inst)=arch/$(SRCARCH)/include/uapi
 
 PHONY += headers_check
-headers_check: headers_install
-	$(Q)$(MAKE) $(hdr-inst)=include/uapi dst=include HDRCHECK=1
-	$(Q)$(MAKE) $(hdr-inst)=arch/$(SRCARCH)/include/uapi $(hdr-dst) HDRCHECK=1
+headers_check: headers
+	$(Q)$(MAKE) $(hdr-inst)=include/uapi HDRCHECK=1
+	$(Q)$(MAKE) $(hdr-inst)=arch/$(SRCARCH)/include/uapi HDRCHECK=1
+
+ifdef CONFIG_HEADERS_INSTALL
+prepare: headers
+endif
 
 ifdef CONFIG_HEADERS_CHECK
 all: headers_check
 endif
 
+PHONY += scripts_unifdef
+scripts_unifdef: scripts_basic
+	$(Q)$(MAKE) $(build)=scripts scripts/unifdef
+
 # ---------------------------------------------------------------------------
 # Kernel selftest
 
@@ -1283,18 +1294,24 @@ all: modules
 # using awk while concatenating to the final file.
 
 PHONY += modules
-modules: $(vmlinux-dirs) $(if $(KBUILD_BUILTIN),vmlinux) modules.builtin
-	$(Q)$(AWK) '!x[$$0]++' $(vmlinux-dirs:%=$(objtree)/%/modules.order) > $(objtree)/modules.order
+modules: $(if $(KBUILD_BUILTIN),vmlinux) modules.order modules.builtin
 	@$(kecho) '  Building modules, stage 2.';
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
 	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/modules-check.sh
 
-modules.builtin: $(vmlinux-dirs:%=%/modules.builtin)
-	$(Q)$(AWK) '!x[$$0]++' $^ > $(objtree)/modules.builtin
+modules.order: $(vmlinux-dirs)
+	$(Q)$(AWK) '!x[$$0]++' $(addsuffix /$@, $(vmlinux-dirs)) > $@
+
+modbuiltin-dirs := $(addprefix _modbuiltin_, $(vmlinux-dirs))
 
-%/modules.builtin: include/config/auto.conf include/config/tristate.conf
-	$(Q)$(MAKE) $(modbuiltin)=$*
+modules.builtin: $(modbuiltin-dirs)
+	$(Q)$(AWK) '!x[$$0]++' $(addsuffix /$@, $(vmlinux-dirs)) > $@
 
+PHONY += $(modbuiltin-dirs)
+# tristate.conf is not included from this Makefile. Add it as a prerequisite
+# here to make it self-healing in case somebody accidentally removes it.
+$(modbuiltin-dirs): include/config/tristate.conf
+	$(Q)$(MAKE) $(modbuiltin)=$(patsubst _modbuiltin_%,%,$@)
 
 # Target to prepare building external modules
 PHONY += modules_prepare
@@ -1360,7 +1377,7 @@ CLEAN_DIRS  += $(MODVERDIR) include/ksym
 CLEAN_FILES += modules.builtin.modinfo
 
 # Directories & files removed with 'make mrproper'
-MRPROPER_DIRS  += include/config usr/include include/generated          \
+MRPROPER_DIRS  += include/config include/generated          \
 		  arch/$(SRCARCH)/include/generated .tmp_objdiff
 MRPROPER_FILES += .config .config.old .version \
 		  Module.symvers tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS \
@@ -1551,7 +1568,7 @@ $(DOC_TARGETS): scripts_basic FORCE
 # ---------------------------------------------------------------------------
 
 PHONY += scripts_gdb
-scripts_gdb: prepare
+scripts_gdb: prepare0
 	$(Q)$(MAKE) $(build)=scripts/gdb
 	$(Q)ln -fsn $(abspath $(srctree)/scripts/gdb/vmlinux-gdb.py)
 
@@ -1698,7 +1715,7 @@ CHECKSTACK_ARCH := $(ARCH)
 endif
 checkstack:
 	$(OBJDUMP) -d vmlinux $$(find . -name '*.ko') | \
-	$(PERL) $(src)/scripts/checkstack.pl $(CHECKSTACK_ARCH)
+	$(PERL) $(srctree)/scripts/checkstack.pl $(CHECKSTACK_ARCH)
 
 kernelrelease:
 	@echo "$(KERNELVERSION)$$($(CONFIG_SHELL) $(srctree)/scripts/setlocalversion $(srctree))"
@@ -1717,11 +1734,11 @@ endif
 
 tools/: FORCE
 	$(Q)mkdir -p $(objtree)/tools
-	$(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(abspath $(objtree)) subdir=tools -C $(src)/tools/
+	$(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(abspath $(objtree)) subdir=tools -C $(srctree)/tools/
 
 tools/%: FORCE
 	$(Q)mkdir -p $(objtree)/tools
-	$(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(abspath $(objtree)) subdir=tools -C $(src)/tools/ $*
+	$(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(abspath $(objtree)) subdir=tools -C $(srctree)/tools/ $*
 
 # Single targets
 # ---------------------------------------------------------------------------
@@ -1755,8 +1772,6 @@ build-dir = $(patsubst %/,%,$(dir $(build-target)))
 PHONY += /
 /: ./
 
-# Make sure the latest headers are built for Documentation
-Documentation/ samples/: headers_install
 %/: prepare FORCE
 	$(Q)$(MAKE) KBUILD_MODULES=1 $(build)=$(build-dir)
 

arch/arc/Makefile

@@ -19,7 +19,7 @@ ifdef CONFIG_ARC_CURR_IN_REG
 # any kernel headers, and missing the r25 global register
 # Can't do unconditionally because of recursive include issues
 # due to <linux/thread_info.h>
-LINUXINCLUDE	+=  -include ${src}/arch/arc/include/asm/current.h
+LINUXINCLUDE	+=  -include $(srctree)/arch/arc/include/asm/current.h
 endif
 
 cflags-y				+= -fsection-anchors

arch/arc/configs/tb10x_defconfig

@@ -94,6 +94,7 @@ CONFIG_CONFIGFS_FS=y
 CONFIG_DEBUG_INFO=y
 CONFIG_STRIP_ASM_SYMS=y
 CONFIG_DEBUG_FS=y
+CONFIG_HEADERS_INSTALL=y
 CONFIG_HEADERS_CHECK=y
 CONFIG_DEBUG_SECTION_MISMATCH=y
 CONFIG_MAGIC_SYSRQ=y

arch/nds32/configs/defconfig

@@ -92,6 +92,7 @@ CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_INFO_DWARF4=y
 CONFIG_GDB_SCRIPTS=y
 CONFIG_READABLE_ASM=y
+CONFIG_HEADERS_INSTALL=y
 CONFIG_HEADERS_CHECK=y
 CONFIG_DEBUG_SECTION_MISMATCH=y
 CONFIG_MAGIC_SYSRQ=y

arch/parisc/Makefile

@@ -120,8 +120,8 @@ PALO := $(shell if (which palo 2>&1); then : ; \
 	elif [ -x /sbin/palo ]; then echo /sbin/palo; \
 	fi)
 
-PALOCONF := $(shell if [ -f $(src)/palo.conf ]; then echo $(src)/palo.conf; \
-	else echo $(obj)/palo.conf; \
+PALOCONF := $(shell if [ -f $(srctree)/palo.conf ]; then echo $(srctree)/palo.conf; \
+	else echo $(objtree)/palo.conf; \
 	fi)
 
 palo lifimage: vmlinuz
@@ -131,8 +131,8 @@ palo lifimage: vmlinuz
 		false; \
 	fi
 	@if test ! -f "$(PALOCONF)"; then \
-		cp $(src)/arch/parisc/defpalo.conf $(obj)/palo.conf; \
-		echo 'A generic palo config file ($(obj)/palo.conf) has been created for you.'; \
+		cp $(srctree)/arch/parisc/defpalo.conf $(objtree)/palo.conf; \
+		echo 'A generic palo config file ($(objree)/palo.conf) has been created for you.'; \
 		echo 'You should check it and re-run "make palo".'; \
 		echo 'WARNING: the "lifimage" file is now placed in this directory by default!'; \
 		false; \
@@ -162,10 +162,10 @@ vmlinuz: vmlinux
 endif
 
 install:
-	$(CONFIG_SHELL) $(src)/arch/parisc/install.sh \
+	$(CONFIG_SHELL) $(srctree)/arch/parisc/install.sh \
 			$(KERNELRELEASE) vmlinux System.map "$(INSTALL_PATH)"
 zinstall:
-	$(CONFIG_SHELL) $(src)/arch/parisc/install.sh \
+	$(CONFIG_SHELL) $(srctree)/arch/parisc/install.sh \
 			$(KERNELRELEASE) vmlinuz System.map "$(INSTALL_PATH)"
 
 CLEAN_FILES	+= lifimage

arch/parisc/configs/a500_defconfig

@@ -166,6 +166,7 @@ CONFIG_NLS_ISO8859_1=m
 CONFIG_NLS_ISO8859_15=m
 CONFIG_NLS_UTF8=m
 CONFIG_DEBUG_FS=y
+CONFIG_HEADERS_INSTALL=y
 CONFIG_HEADERS_CHECK=y
 CONFIG_MAGIC_SYSRQ=y
 # CONFIG_DEBUG_BUGVERBOSE is not set

arch/parisc/configs/b180_defconfig

@@ -90,6 +90,7 @@ CONFIG_NLS_ASCII=m
 CONFIG_NLS_ISO8859_1=m
 CONFIG_NLS_ISO8859_15=m
 CONFIG_NLS_UTF8=m
+CONFIG_HEADERS_INSTALL=y
 CONFIG_HEADERS_CHECK=y
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_KERNEL=y

arch/parisc/configs/c3000_defconfig

@@ -139,6 +139,7 @@ CONFIG_NLS_ISO8859_1=m
 CONFIG_NLS_ISO8859_15=m
 CONFIG_NLS_UTF8=m
 CONFIG_DEBUG_FS=y
+CONFIG_HEADERS_INSTALL=y
 CONFIG_HEADERS_CHECK=y
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_MUTEXES=y

arch/parisc/configs/default_defconfig

@@ -183,6 +183,7 @@ CONFIG_NLS_KOI8_R=m
 CONFIG_NLS_KOI8_U=m
 CONFIG_NLS_UTF8=y
 CONFIG_DEBUG_FS=y
+CONFIG_HEADERS_INSTALL=y
 CONFIG_HEADERS_CHECK=y
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_KERNEL=y

arch/powerpc/configs/ppc6xx_defconfig

@@ -1123,6 +1123,7 @@ CONFIG_NLS_KOI8_R=m
 CONFIG_NLS_KOI8_U=m
 CONFIG_DEBUG_INFO=y
 CONFIG_UNUSED_SYMBOLS=y
+CONFIG_HEADERS_INSTALL=y
 CONFIG_HEADERS_CHECK=y
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_KERNEL=y

arch/s390/configs/debug_defconfig

@@ -588,6 +588,7 @@ CONFIG_GDB_SCRIPTS=y
 CONFIG_FRAME_WARN=1024
 CONFIG_READABLE_ASM=y
 CONFIG_UNUSED_SYMBOLS=y
+CONFIG_HEADERS_INSTALL=y
 CONFIG_HEADERS_CHECK=y
 CONFIG_DEBUG_SECTION_MISMATCH=y
 CONFIG_MAGIC_SYSRQ=y

arch/um/Makefile

@@ -73,7 +73,7 @@ KBUILD_AFLAGS += $(ARCH_INCLUDE)
 USER_CFLAGS = $(patsubst $(KERNEL_DEFINES),,$(patsubst -I%,,$(KBUILD_CFLAGS))) \
 		$(ARCH_INCLUDE) $(MODE_INCLUDE) $(filter -I%,$(CFLAGS)) \
 		-D_FILE_OFFSET_BITS=64 -idirafter $(srctree)/include \
-		-idirafter $(obj)/include -D__KERNEL__ -D__UM_HOST__
+		-idirafter $(objtree)/include -D__KERNEL__ -D__UM_HOST__
 
 #This will adjust *FLAGS accordingly to the platform.
 include $(ARCH_DIR)/Makefile-os-$(OS)

drivers/gpu/drm/i915/.gitignore

-header_test_*.c

drivers/gpu/drm/i915/Makefile.header-test

@@ -2,7 +2,7 @@
 # Copyright © 2019 Intel Corporation
 
 # Test the headers are compilable as standalone units
-header_test := \
+header-test-$(CONFIG_DRM_I915_WERROR) := \
 	i915_active_types.h \
 	i915_gem_context_types.h \
 	i915_priolist_types.h \
@@ -35,13 +35,3 @@ header_test := \
 	intel_sprite.h \
 	intel_tv.h \
 	intel_workarounds_types.h
-
-quiet_cmd_header_test = HDRTEST $@
-      cmd_header_test = echo "\#include \"$(<F)\"" > $@
-
-header_test_%.c: %.h
-	$(call cmd,header_test)
-
-i915-$(CONFIG_DRM_I915_WERROR) += $(foreach h,$(header_test),$(patsubst %.h,header_test_%.o,$(h)))
-
-clean-files += $(foreach h,$(header_test),$(patsubst %.h,header_test_%.c,$(h)))

include/uapi/linux/Kbuild → include/uapi/Kbuild

 # SPDX-License-Identifier: GPL-2.0
 ifeq ($(wildcard $(srctree)/arch/$(SRCARCH)/include/uapi/asm/a.out.h),)
-no-export-headers += a.out.h
+no-export-headers += linux/a.out.h
 endif
 
 ifeq ($(wildcard $(srctree)/arch/$(SRCARCH)/include/uapi/asm/kvm.h),)
-no-export-headers += kvm.h
+no-export-headers += linux/kvm.h
 endif
 
 ifeq ($(wildcard $(srctree)/arch/$(SRCARCH)/include/uapi/asm/kvm_para.h),)
 ifeq ($(wildcard $(objtree)/arch/$(SRCARCH)/include/generated/uapi/asm/kvm_para.h),)
-no-export-headers += kvm_para.h
+no-export-headers += linux/kvm_para.h
 endif
 endif

init/Kconfig

@@ -24,6 +24,9 @@ config CLANG_VERSION
 	int
 	default $(shell,$(srctree)/scripts/clang-version.sh $(CC))
 
+config CC_CAN_LINK
+	def_bool $(success,$(srctree)/scripts/cc-can-link.sh $(CC))
+
 config CC_HAS_ASM_GOTO
 	def_bool $(success,$(srctree)/scripts/gcc-goto.sh $(CC))
 
@@ -96,6 +99,36 @@ config COMPILE_TEST
 	  here. If you are a user/distributor, say N here to exclude useless
 	  drivers to be distributed.
 
+config HEADER_TEST
+	bool "Compile test headers that should be standalone compilable"
+	help
+	  Compile test headers listed in header-test-y target to ensure they are
+	  self-contained, i.e. compilable as standalone units.
+
+	  If you are a developer or tester and want to ensure the requested
+	  headers are self-contained, say Y here. Otherwise, choose N.
+
+config KERNEL_HEADER_TEST
+	bool "Compile test kernel headers"
+	depends on HEADER_TEST
+	help
+	  Headers in include/ are used to build external moduls.
+	  Compile test them to ensure they are self-contained, i.e.
+	  compilable as standalone units.
+
+	  If you are a developer or tester and want to ensure the headers
+	  in include/ are self-contained, say Y here. Otherwise, choose N.
+
+config UAPI_HEADER_TEST
+	bool "Compile test UAPI headers"
+	depends on HEADER_TEST && HEADERS_INSTALL && CC_CAN_LINK
+	help
+	  Compile test headers exported to user-space to ensure they are
+	  self-contained, i.e. compilable as standalone units.
+
+	  If you are a developer or tester and want to ensure the exported
+	  headers are self-contained, say Y here. Otherwise, choose N.
+
 config LOCALVERSION
 	string "Local version - append to kernel release"
 	help

kernel/gen_kheaders.sh

@@ -4,24 +4,12 @@
 # This script generates an archive consisting of kernel headers
 # for CONFIG_IKHEADERS.
 set -e
-spath="$(dirname "$(readlink -f "$0")")"
-kroot="$spath/.."
+sfile="$(readlink -f "$0")"
 outdir="$(pwd)"
 tarfile=$1
 cpio_dir=$outdir/$tarfile.tmp
 
-# Script filename relative to the kernel source root
-# We add it to the archive because it is small and any changes
-# to this script will also cause a rebuild of the archive.
-sfile="$(realpath --relative-to $kroot "$(readlink -f "$0")")"
-
-src_file_list="
-include/
-arch/$SRCARCH/include/
-$sfile
-"
-
-obj_file_list="
+dir_list="
 include/
 arch/$SRCARCH/include/
 "
@@ -33,33 +21,29 @@ arch/$SRCARCH/include/
 # Uncomment it for debugging.
 # if [ ! -f /tmp/iter ]; then iter=1; echo 1 > /tmp/iter;
 # else iter=$(($(cat /tmp/iter) + 1)); echo $iter > /tmp/iter; fi
-# find $src_file_list -type f | xargs ls -lR > /tmp/src-ls-$iter
-# find $obj_file_list -type f | xargs ls -lR > /tmp/obj-ls-$iter
+# find $src_file_list -name "*.h" | xargs ls -l > /tmp/src-ls-$iter
+# find $obj_file_list -name "*.h" | xargs ls -l > /tmp/obj-ls-$iter
 
 # include/generated/compile.h is ignored because it is touched even when none
 # of the source files changed. This causes pointless regeneration, so let us
 # ignore them for md5 calculation.
-pushd $kroot > /dev/null
-src_files_md5="$(find $src_file_list -type f                       |
+pushd $srctree > /dev/null
+src_files_md5="$(find $dir_list -name "*.h"			   |
 		grep -v "include/generated/compile.h"		   |
 		grep -v "include/generated/autoconf.h"		   |
-		grep -v "include/config/auto.conf"		   |
-		grep -v "include/config/auto.conf.cmd"		   |
-		grep -v "include/config/tristate.conf"		   |
-		xargs ls -lR | md5sum | cut -d ' ' -f1)"
+		xargs ls -l | md5sum | cut -d ' ' -f1)"
 popd > /dev/null
-obj_files_md5="$(find $obj_file_list -type f                       |
+obj_files_md5="$(find $dir_list -name "*.h"			   |
 		grep -v "include/generated/compile.h"		   |
 		grep -v "include/generated/autoconf.h"		   |
-		grep -v "include/config/auto.conf"                 |
-		grep -v "include/config/auto.conf.cmd"		   |
-		grep -v "include/config/tristate.conf"		   |
-		xargs ls -lR | md5sum | cut -d ' ' -f1)"
-
+		xargs ls -l | md5sum | cut -d ' ' -f1)"
+# Any changes to this script will also cause a rebuild of the archive.
+this_file_md5="$(ls -l $sfile | md5sum | cut -d ' ' -f1)"
 if [ -f $tarfile ]; then tarfile_md5="$(md5sum $tarfile | cut -d ' ' -f1)"; fi
 if [ -f kernel/kheaders.md5 ] &&
 	[ "$(cat kernel/kheaders.md5|head -1)" == "$src_files_md5" ] &&
 	[ "$(cat kernel/kheaders.md5|head -2|tail -1)" == "$obj_files_md5" ] &&
+	[ "$(cat kernel/kheaders.md5|head -3|tail -1)" == "$this_file_md5" ] &&
 	[ "$(cat kernel/kheaders.md5|tail -1)" == "$tarfile_md5" ]; then
 		exit
 fi
@@ -71,16 +55,16 @@ fi
 rm -rf $cpio_dir
 mkdir $cpio_dir
 
-pushd $kroot > /dev/null
-for f in $src_file_list;
-	do find "$f" ! -name "*.cmd" ! -name ".*";
+pushd $srctree > /dev/null
+for f in $dir_list;
+	do find "$f" -name "*.h";
 done | cpio --quiet -pd $cpio_dir
 popd > /dev/null
 
 # The second CPIO can complain if files already exist which can
 # happen with out of tree builds. Just silence CPIO for now.
-for f in $obj_file_list;
-	do find "$f" ! -name "*.cmd" ! -name ".*";
+for f in $dir_list;
+	do find "$f" -name "*.h";
 done | cpio --quiet -pd $cpio_dir >/dev/null 2>&1
 
 # Remove comments except SDPX lines
@@ -91,6 +75,7 @@ tar -Jcf $tarfile -C $cpio_dir/ . > /dev/null
 
 echo "$src_files_md5" >  kernel/kheaders.md5
 echo "$obj_files_md5" >> kernel/kheaders.md5
+echo "$this_file_md5" >> kernel/kheaders.md5
 echo "$(md5sum $tarfile | cut -d ' ' -f1)" >> kernel/kheaders.md5
 
 rm -rf $cpio_dir

lib/Kconfig.debug

@@ -305,19 +305,26 @@ config DEBUG_FS
 
 	  If unsure, say N.
 
-config HEADERS_CHECK
-	bool "Run 'make headers_check' when building vmlinux"
+config HEADERS_INSTALL
+	bool "Install uapi headers to usr/include"
 	depends on !UML
 	help
-	  This option will extract the user-visible kernel headers whenever
-	  building the kernel, and will run basic sanity checks on them to
-	  ensure that exported files do not attempt to include files which
-	  were not exported, etc.
+	  This option will install uapi headers (headers exported to user-space)
+	  into the usr/include directory for use during the kernel build.
+	  This is unneeded for building the kernel itself, but needed for some
+	  user-space program samples. It is also needed by some features such
+	  as uapi header sanity checks.
+
+config HEADERS_CHECK
+	bool "Run sanity checks on uapi headers when building 'all'"
+	depends on HEADERS_INSTALL
+	help
+	  This option will run basic sanity checks on uapi headers when
+	  building the 'all' target, for example, ensure that they do not
+	  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'"

lib/raid6/Makefile

@@ -12,9 +12,6 @@ raid6_pq-$(CONFIG_S390) += s390vx8.o recov_s390xc.o
 
 hostprogs-y	+= mktables
 
-quiet_cmd_unroll = UNROLL  $@
-      cmd_unroll = $(AWK) -f$(srctree)/$(src)/unroll.awk -vN=$(UNROLL) < $< > $@
-
 ifeq ($(CONFIG_ALTIVEC),y)
 altivec_flags := -maltivec $(call cc-option,-mabi=altivec)
 
@@ -26,7 +23,6 @@ CFLAGS_REMOVE_altivec1.o  += -msoft-float
 CFLAGS_REMOVE_altivec2.o  += -msoft-float
 CFLAGS_REMOVE_altivec4.o  += -msoft-float
 CFLAGS_REMOVE_altivec8.o  += -msoft-float
-CFLAGS_REMOVE_altivec8.o  += -msoft-float
 CFLAGS_REMOVE_vpermxor1.o += -msoft-float
 CFLAGS_REMOVE_vpermxor2.o += -msoft-float
 CFLAGS_REMOVE_vpermxor4.o += -msoft-float
@@ -51,111 +47,39 @@ CFLAGS_REMOVE_neon8.o += -mgeneral-regs-only
 endif
 endif
 
-targets += int1.c
-$(obj)/int1.c:   UNROLL := 1
-$(obj)/int1.c:   $(src)/int.uc $(src)/unroll.awk FORCE
-	$(call if_changed,unroll)
-
-targets += int2.c
-$(obj)/int2.c:   UNROLL := 2
-$(obj)/int2.c:   $(src)/int.uc $(src)/unroll.awk FORCE
-	$(call if_changed,unroll)
-
-targets += int4.c
-$(obj)/int4.c:   UNROLL := 4
-$(obj)/int4.c:   $(src)/int.uc $(src)/unroll.awk FORCE
-	$(call if_changed,unroll)
-
-targets += int8.c
-$(obj)/int8.c:   UNROLL := 8
-$(obj)/int8.c:   $(src)/int.uc $(src)/unroll.awk FORCE
-	$(call if_changed,unroll)
-
-targets += int16.c
-$(obj)/int16.c:  UNROLL := 16
-$(obj)/int16.c:  $(src)/int.uc $(src)/unroll.awk FORCE
-	$(call if_changed,unroll)
+quiet_cmd_unroll = UNROLL  $@
+      cmd_unroll = $(AWK) -f$(srctree)/$(src)/unroll.awk -vN=$* < $< > $@
 
-targets += int32.c
-$(obj)/int32.c:  UNROLL := 32
-$(obj)/int32.c:  $(src)/int.uc $(src)/unroll.awk FORCE
+targets += int1.c int2.c int4.c int8.c int16.c int32.c
+$(obj)/int%.c: $(src)/int.uc $(src)/unroll.awk FORCE
 	$(call if_changed,unroll)
 
 CFLAGS_altivec1.o += $(altivec_flags)
-targets += altivec1.c
-$(obj)/altivec1.c:   UNROLL := 1
-$(obj)/altivec1.c:   $(src)/altivec.uc $(src)/unroll.awk FORCE
-	$(call if_changed,unroll)
-
 CFLAGS_altivec2.o += $(altivec_flags)
-targets += altivec2.c
-$(obj)/altivec2.c:   UNROLL := 2
-$(obj)/altivec2.c:   $(src)/altivec.uc $(src)/unroll.awk FORCE
-	$(call if_changed,unroll)
-
 CFLAGS_altivec4.o += $(altivec_flags)
-targets += altivec4.c
-$(obj)/altivec4.c:   UNROLL := 4
-$(obj)/altivec4.c:   $(src)/altivec.uc $(src)/unroll.awk FORCE
-	$(call if_changed,unroll)
-
 CFLAGS_altivec8.o += $(altivec_flags)
-targets += altivec8.c
-$(obj)/altivec8.c:   UNROLL := 8
-$(obj)/altivec8.c:   $(src)/altivec.uc $(src)/unroll.awk FORCE
+targets += altivec1.c altivec2.c altivec4.c altivec8.c
+$(obj)/altivec%.c: $(src)/altivec.uc $(src)/unroll.awk FORCE
 	$(call if_changed,unroll)
 
 CFLAGS_vpermxor1.o += $(altivec_flags)
-targets += vpermxor1.c
-$(obj)/vpermxor1.c: UNROLL := 1
-$(obj)/vpermxor1.c: $(src)/vpermxor.uc $(src)/unroll.awk FORCE
-	$(call if_changed,unroll)
-
 CFLAGS_vpermxor2.o += $(altivec_flags)
-targets += vpermxor2.c
-$(obj)/vpermxor2.c: UNROLL := 2
-$(obj)/vpermxor2.c: $(src)/vpermxor.uc $(src)/unroll.awk FORCE
-	$(call if_changed,unroll)
-
 CFLAGS_vpermxor4.o += $(altivec_flags)
-targets += vpermxor4.c
-$(obj)/vpermxor4.c: UNROLL := 4
-$(obj)/vpermxor4.c: $(src)/vpermxor.uc $(src)/unroll.awk FORCE
-	$(call if_changed,unroll)
-
 CFLAGS_vpermxor8.o += $(altivec_flags)
-targets += vpermxor8.c
-$(obj)/vpermxor8.c: UNROLL := 8
-$(obj)/vpermxor8.c: $(src)/vpermxor.uc $(src)/unroll.awk FORCE
+targets += vpermxor1.o vpermxor2.o vpermxor4.o vpermxor8.o
+$(obj)/vpermxor%.c: $(src)/vpermxor.uc $(src)/unroll.awk FORCE
 	$(call if_changed,unroll)
 
 CFLAGS_neon1.o += $(NEON_FLAGS)
-targets += neon1.c
-$(obj)/neon1.c:   UNROLL := 1
-$(obj)/neon1.c:   $(src)/neon.uc $(src)/unroll.awk FORCE
-	$(call if_changed,unroll)
-
 CFLAGS_neon2.o += $(NEON_FLAGS)
-targets += neon2.c
-$(obj)/neon2.c:   UNROLL := 2
-$(obj)/neon2.c:   $(src)/neon.uc $(src)/unroll.awk FORCE
-	$(call if_changed,unroll)
-
 CFLAGS_neon4.o += $(NEON_FLAGS)
-targets += neon4.c
-$(obj)/neon4.c:   UNROLL := 4
-$(obj)/neon4.c:   $(src)/neon.uc $(src)/unroll.awk FORCE
-	$(call if_changed,unroll)
-
 CFLAGS_neon8.o += $(NEON_FLAGS)
-targets += neon8.c
-$(obj)/neon8.c:   UNROLL := 8
-$(obj)/neon8.c:   $(src)/neon.uc $(src)/unroll.awk FORCE
+targets += neon1.c neon2.c neon4.c neon8.c
+$(obj)/neon%.c: $(src)/neon.uc $(src)/unroll.awk FORCE
 	$(call if_changed,unroll)
 
 targets += s390vx8.c
-$(obj)/s390vx8.c:   UNROLL := 8
-$(obj)/s390vx8.c:   $(src)/s390vx.uc $(src)/unroll.awk FORCE
+$(obj)/s390vx%.c: $(src)/s390vx.uc $(src)/unroll.awk FORCE
 	$(call if_changed,unroll)
 
 quiet_cmd_mktable = TABLE   $@

net/bpfilter/Kconfig

@@ -9,7 +9,7 @@ menuconfig BPFILTER
 if BPFILTER
 config BPFILTER_UMH
 	tristate "bpfilter kernel module with user mode helper"
-	depends on $(success,$(srctree)/scripts/cc-can-link.sh $(CC))
+	depends on CC_CAN_LINK
 	default m
 	help
 	  This builds bpfilter kernel module with embedded user mode helper

samples/Kconfig

 # SPDX-License-Identifier: GPL-2.0-only
 menuconfig SAMPLES
 	bool "Sample kernel code"
-	depends on !UML
 	help
 	  You can build and test sample kernel code here.
 
@@ -95,16 +94,24 @@ config SAMPLE_CONFIGFS
 
 config SAMPLE_CONNECTOR
 	tristate "Build connector sample -- loadable modules only"
-	depends on CONNECTOR && m
+	depends on CONNECTOR && HEADERS_INSTALL && m
 	help
 	  When enabled, this builds both a sample kernel module for
 	  the connector interface and a user space tool to communicate
 	  with it.
 	  See also Documentation/connector/connector.txt
 
+config SAMPLE_HIDRAW
+	bool "hidraw sample"
+	depends on HEADERS_INSTALL
+
+config SAMPLE_PIDFD
+	bool "pidfd sample"
+	depends on HEADERS_INSTALL
+
 config SAMPLE_SECCOMP
 	bool "Build seccomp sample code"
-	depends on SECCOMP_FILTER
+	depends on SECCOMP_FILTER && HEADERS_INSTALL
 	help
 	  Build samples of seccomp filters using various methods of
 	  BPF filter construction.
@@ -156,6 +163,7 @@ config SAMPLE_ANDROID_BINDERFS
 
 config SAMPLE_VFS
 	bool "Build example programs that use new VFS system calls"
+	depends on HEADERS_INSTALL
 	help
 	  Build example userspace programs that use new VFS system calls such
 	  as mount API and statx().  Note that this is restricted to the x86

samples/Makefile

@@ -4,14 +4,14 @@
 obj-$(CONFIG_SAMPLE_ANDROID_BINDERFS)	+= binderfs/
 obj-$(CONFIG_SAMPLE_CONFIGFS)		+= configfs/
 obj-$(CONFIG_SAMPLE_CONNECTOR)		+= connector/
-subdir-y				+= hidraw
+subdir-$(CONFIG_SAMPLE_HIDRAW)		+= hidraw
 obj-$(CONFIG_SAMPLE_HW_BREAKPOINT)	+= hw_breakpoint/
 obj-$(CONFIG_SAMPLE_KDB)		+= kdb/
 obj-$(CONFIG_SAMPLE_KFIFO)		+= kfifo/
 obj-$(CONFIG_SAMPLE_KOBJECT)		+= kobject/
 obj-$(CONFIG_SAMPLE_KPROBES)		+= kprobes/
 obj-$(CONFIG_SAMPLE_LIVEPATCH)		+= livepatch/
-subdir-y				+= pidfd
+subdir-$(CONFIG_SAMPLE_PIDFD)		+= pidfd
 obj-$(CONFIG_SAMPLE_QMI_CLIENT)		+= qmi/
 obj-$(CONFIG_SAMPLE_RPMSG_CLIENT)	+= rpmsg/
 subdir-$(CONFIG_SAMPLE_SECCOMP)		+= seccomp

scripts/Kbuild.include

@@ -79,8 +79,8 @@ endef
 # would try to directly execute the shell builtin 'command'. This workaround
 # should be kept for a long time since this issue was fixed only after the
 # GNU Make 4.2.1 release.
-cc-cross-prefix = $(firstword $(foreach c, $(filter-out -%, $(1)), \
-			$(if $(shell command -v $(c)gcc 2>/dev/null), $(c))))
+cc-cross-prefix = $(firstword $(foreach c, $(1), \
+			$(if $(shell command -v -- $(c)gcc 2>/dev/null), $(c))))
 
 # output directory for tests below
 TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)
@@ -187,12 +187,6 @@ dtbinst := -f $(srctree)/scripts/Makefile.dtbinst obj
 # $(Q)$(MAKE) $(clean)=dir
 clean := -f $(srctree)/scripts/Makefile.clean obj
 
-###
-# Shorthand for $(Q)$(MAKE) -f scripts/Makefile.headersinst obj=
-# Usage:
-# $(Q)$(MAKE) $(hdr-inst)=dir
-hdr-inst := -f $(srctree)/scripts/Makefile.headersinst obj
-
 # echo command.
 # Short version is used, if $(quiet) equals `quiet_', otherwise full one.
 echo-cmd = $(if $($(quiet)cmd_$(1)),\
@@ -213,12 +207,12 @@ objectify = $(foreach o,$(1),$(if $(filter /%,$(o)),$(o),$(obj)/$(o)))
 # See Documentation/kbuild/makefiles.rst for more info
 
 ifneq ($(KBUILD_NOCMDDEP),1)
-# Check if both arguments are the same including their order. Result is empty
+# Check if both commands are the same including their order. Result is empty
 # string if equal. User may override this check using make KBUILD_NOCMDDEP=1
-arg-check = $(filter-out $(subst $(space),$(space_escape),$(strip $(cmd_$@))), \
+cmd-check = $(filter-out $(subst $(space),$(space_escape),$(strip $(cmd_$@))), \
                          $(subst $(space),$(space_escape),$(strip $(cmd_$1))))
 else
-arg-check = $(if $(strip $(cmd_$@)),,1)
+cmd-check = $(if $(strip $(cmd_$@)),,1)
 endif
 
 # Replace >$< with >$$< to preserve $ when reloading the .cmd file
@@ -231,15 +225,15 @@ make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1))))
 
 # Find any prerequisites that is newer than target or that does not exist.
 # PHONY targets skipped in both cases.
-any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
+any-prereq = $(filter-out $(PHONY),$?)$(filter-out $(PHONY) $(wildcard $^),$^)
 
 # Execute command if command has changed or prerequisite(s) are updated.
-if_changed = $(if $(strip $(any-prereq) $(arg-check)),                       \
+if_changed = $(if $(any-prereq)$(cmd-check),                                 \
 	$(cmd);                                                              \
 	printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
 
 # Execute the command and also postprocess generated .d dependencies file.
-if_changed_dep = $(if $(strip $(any-prereq) $(arg-check)),$(cmd_and_fixdep),@:)
+if_changed_dep = $(if $(any-prereq)$(cmd-check),$(cmd_and_fixdep),@:)
 
 cmd_and_fixdep =                                                             \
 	$(cmd);                                                              \
@@ -249,7 +243,7 @@ cmd_and_fixdep =                                                             \
 # Usage: $(call if_changed_rule,foo)
 # Will check if $(cmd_foo) or any of the prerequisites changed,
 # and if so will execute $(rule_foo).
-if_changed_rule = $(if $(strip $(any-prereq) $(arg-check)),$(rule_$(1)),@:)
+if_changed_rule = $(if $(any-prereq)$(cmd-check),$(rule_$(1)),@:)
 
 ###
 # why - tell why a target got built
@@ -274,8 +268,8 @@ ifeq ($(KBUILD_VERBOSE),2)
 why =                                                                        \
     $(if $(filter $@, $(PHONY)),- due to target is PHONY,                    \
         $(if $(wildcard $@),                                                 \
-            $(if $(strip $(any-prereq)),- due to: $(any-prereq),             \
-                $(if $(arg-check),                                           \
+            $(if $(any-prereq),- due to: $(any-prereq),                      \
+                $(if $(cmd-check),                                           \
                     $(if $(cmd_$@),- due to command line change,             \
                         $(if $(filter $@, $(targets)),                       \
                             - due to missing .cmd file,                      \

scripts/Makefile

@@ -31,11 +31,6 @@ always		:= $(hostprogs-y) $(hostprogs-m)
 # The following hostprogs-y programs are only build on demand
 hostprogs-y += unifdef
 
-# These targets are used internally to avoid "is up to date" messages
-PHONY += build_unifdef
-build_unifdef: $(obj)/unifdef
-	@:
-
 subdir-$(CONFIG_GCC_PLUGINS) += gcc-plugins
 subdir-$(CONFIG_MODVERSIONS) += genksyms
 subdir-$(CONFIG_SECURITY_SELINUX) += selinux

scripts/Makefile.build

@@ -294,6 +294,15 @@ quiet_cmd_cc_lst_c = MKLST   $@
 $(obj)/%.lst: $(src)/%.c FORCE
 	$(call if_changed_dep,cc_lst_c)
 
+# header test (header-test-y target)
+# ---------------------------------------------------------------------------
+
+quiet_cmd_cc_s_h = CC      $@
+      cmd_cc_s_h = $(CC) $(c_flags) -S -o $@ -x c /dev/null -include $<
+
+$(obj)/%.h.s: $(src)/%.h FORCE
+	$(call if_changed_dep,cc_s_h)
+
 # Compile assembler sources (.S)
 # ---------------------------------------------------------------------------
 
@@ -504,7 +513,7 @@ existing-targets := $(wildcard $(sort $(targets)))
 
 -include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
 
-ifneq ($(srctree),.)
+ifdef building_out_of_srctree
 # Create directories for object files if they do not exist
 obj-dirs := $(sort $(obj) $(patsubst %/,%, $(dir $(targets))))
 # If targets exist, their directories apparently exist. Skip mkdir.

scripts/Makefile.extrawarn

@@ -34,7 +34,6 @@ warning-1 += $(call cc-option, -Wstringop-truncation)
 warning-1 += -Wno-missing-field-initializers
 warning-1 += -Wno-sign-compare
 
-warning-2 := -Waggregate-return
 warning-2 += -Wcast-align
 warning-2 += -Wdisabled-optimization
 warning-2 += -Wnested-externs
@@ -68,10 +67,8 @@ else
 
 ifdef CONFIG_CC_IS_CLANG
 KBUILD_CFLAGS += -Wno-initializer-overrides
-KBUILD_CFLAGS += -Wno-unused-value
 KBUILD_CFLAGS += -Wno-format
 KBUILD_CFLAGS += -Wno-sign-compare
 KBUILD_CFLAGS += -Wno-format-zero-length
-KBUILD_CFLAGS += -Wno-uninitialized
 endif
 endif

scripts/Makefile.headersinst

@@ -14,109 +14,89 @@ __headers:
 
 include scripts/Kbuild.include
 
-srcdir        := $(srctree)/$(obj)
+src := $(srctree)/$(obj)
+gen := $(objtree)/$(subst include/,include/generated/,$(obj))
+dst := usr/include
 
-# When make is run under a fakechroot environment, the function
-# $(wildcard $(srcdir)/*/.) doesn't only return directories, but also regular
-# files. So, we are using a combination of sort/dir/wildcard which works
-# with fakechroot.
-subdirs       := $(patsubst $(srcdir)/%/,%,\
-		 $(filter-out $(srcdir)/,\
-		 $(sort $(dir $(wildcard $(srcdir)/*/)))))
+-include $(src)/Kbuild
 
-# Recursion
-__headers: $(subdirs)
+# $(filter %/, ...) is a workaround for GNU Make <= 4.2.1, where
+# $(wildcard $(src)/*/) contains not only directories but also regular files.
+src-subdirs := $(patsubst $(src)/%/,%,$(filter %/, $(wildcard $(src)/*/)))
+gen-subdirs := $(patsubst $(gen)/%/,%,$(filter %/, $(wildcard $(gen)/*/)))
+all-subdirs := $(sort $(src-subdirs) $(gen-subdirs))
 
-PHONY += $(subdirs)
-$(subdirs):
-	$(Q)$(MAKE) $(hdr-inst)=$(obj)/$@ dst=$(dst)/$@
+src-headers := $(if $(src-subdirs), $(shell cd $(src) && find $(src-subdirs) -name '*.h'))
+src-headers := $(filter-out $(no-export-headers), $(src-headers))
+gen-headers := $(if $(gen-subdirs), $(shell cd $(gen) && find $(gen-subdirs) -name '*.h'))
+gen-headers := $(filter-out $(no-export-headers), $(gen-headers))
 
-# Skip header install/check for include/uapi and arch/$(SRCARCH)/include/uapi.
-# We have only sub-directories there.
-skip-inst := $(if $(filter %/uapi,$(obj)),1)
+# If the same header is exported from source and generated directories,
+# the former takes precedence, but this should be warned.
+duplicated := $(filter $(gen-headers), $(src-headers))
+$(if $(duplicated), $(warning duplicated header export: $(duplicated)))
 
-ifeq ($(skip-inst),)
+gen-headers := $(filter-out $(duplicated), $(gen-headers))
 
-# Kbuild file is optional
-kbuild-file := $(srctree)/$(obj)/Kbuild
--include $(kbuild-file)
+# Add dst path prefix
+all-subdirs := $(addprefix $(dst)/, $(all-subdirs))
+src-headers := $(addprefix $(dst)/, $(src-headers))
+gen-headers := $(addprefix $(dst)/, $(gen-headers))
+all-headers := $(src-headers) $(gen-headers)
 
-installdir    := $(INSTALL_HDR_PATH)/$(dst)
-gendir        := $(objtree)/$(subst include/,include/generated/,$(obj))
-header-files  := $(notdir $(wildcard $(srcdir)/*.h))
-header-files  := $(filter-out $(no-export-headers), $(header-files))
-genhdr-files  := $(notdir $(wildcard $(gendir)/*.h))
-genhdr-files  := $(filter-out $(header-files), $(genhdr-files))
+# Work out what needs to be removed
+old-subdirs := $(wildcard $(all-subdirs))
+old-headers := $(if $(old-subdirs),$(shell find $(old-subdirs) -name '*.h'))
+unwanted    := $(filter-out $(all-headers), $(old-headers))
 
-# files used to track state of install/check
-install-file  := $(installdir)/.install
-check-file    := $(installdir)/.check
+# Create directories
+existing-dirs := $(sort $(dir $(old-headers)))
+wanted-dirs   := $(sort $(dir $(all-headers)))
+new-dirs      := $(filter-out $(existing-dirs), $(wanted-dirs))
+$(if $(new-dirs), $(shell mkdir -p $(new-dirs)))
 
-# all headers files for this dir
-all-files     := $(header-files) $(genhdr-files)
-output-files  := $(addprefix $(installdir)/, $(all-files))
+# Rules
 
-# Work out what needs to be removed
-oldheaders    := $(patsubst $(installdir)/%,%,$(wildcard $(installdir)/*.h))
-unwanted      := $(filter-out $(all-files),$(oldheaders))
+ifndef HDRCHECK
 
-# Prefix unwanted with full paths to $(INSTALL_HDR_PATH)
-unwanted-file := $(addprefix $(installdir)/, $(unwanted))
+quiet_cmd_install = HDRINST $@
+      cmd_install = $(CONFIG_SHELL) $(srctree)/scripts/headers_install.sh $< $@
 
-printdir = $(patsubst $(INSTALL_HDR_PATH)/%/,%,$(dir $@))
+$(src-headers): $(dst)/%.h: $(src)/%.h $(srctree)/scripts/headers_install.sh FORCE
+	$(call if_changed,install)
 
-quiet_cmd_install = INSTALL $(printdir) ($(words $(all-files))\
-                            file$(if $(word 2, $(all-files)),s))
-      cmd_install = \
-        $(CONFIG_SHELL) $< $(installdir) $(srcdir) $(header-files); \
-        $(CONFIG_SHELL) $< $(installdir) $(gendir) $(genhdr-files); \
-        touch $@
+$(gen-headers): $(dst)/%.h: $(gen)/%.h $(srctree)/scripts/headers_install.sh FORCE
+	$(call if_changed,install)
 
 quiet_cmd_remove = REMOVE  $(unwanted)
-      cmd_remove = rm -f $(unwanted-file)
-
-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 $(all-files); do                          \
-                  echo "$(installdir)/$${f}"; done                      \
-                  | xargs                                            \
-                  $(PERL) $< $(INSTALL_HDR_PATH)/include $(SRCARCH); \
-	          touch $@
+      cmd_remove = rm -f $(unwanted)
 
-ifndef HDRCHECK
-# Rules for installing headers
-__headers: $(install-file)
+__headers: $(all-headers)
+ifneq ($(unwanted),)
+	$(call cmd,remove)
+endif
 	@:
 
-targets += $(install-file)
-$(install-file): scripts/headers_install.sh \
-		 $(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)
+existing-headers := $(filter $(old-headers), $(all-headers))
+
+-include $(foreach f,$(existing-headers),$(dir $(f)).$(notdir $(f)).cmd)
 
 else
-__headers: $(check-file)
-	@:
 
-targets += $(check-file)
-$(check-file): scripts/headers_check.pl $(output-files) FORCE
-	$(call if_changed,check)
+quiet_cmd_check = HDRCHK  $<
+      cmd_check = $(PERL) $(srctree)/scripts/headers_check.pl $(dst) $(SRCARCH) $<; touch $@
 
-endif
+check-files := $(addsuffix .chk, $(all-headers))
 
-cmd_files := $(wildcard \
-             $(foreach f,$(sort $(targets)),$(dir $(f)).$(notdir $(f)).cmd))
+$(check-files): $(dst)/%.chk : $(dst)/% $(srctree)/scripts/headers_check.pl
+	$(call cmd,check)
 
-ifneq ($(cmd_files),)
-	include $(cmd_files)
-endif
+__headers: $(check-files)
+	@:
 
-endif # skip-inst
+endif
 
 PHONY += FORCE
-FORCE: ;
+FORCE:
 
 .PHONY: $(PHONY)

scripts/Makefile.host

@@ -69,7 +69,7 @@ _hostcxx_flags = $(KBUILD_HOSTCXXFLAGS) $(HOST_EXTRACXXFLAGS) \
 
 # $(objtree)/$(obj) for including generated headers from checkin source files
 ifeq ($(KBUILD_EXTMOD),)
-ifneq ($(srctree),.)
+ifdef building_out_of_srctree
 _hostc_flags   += -I $(objtree)/$(obj)
 _hostcxx_flags += -I $(objtree)/$(obj)
 endif

scripts/Makefile.lib

@@ -66,6 +66,20 @@ extra-y += $(patsubst %.dtb,%.dt.yaml, $(dtb-y))
 extra-$(CONFIG_OF_ALL_DTBS) += $(patsubst %.dtb,%.dt.yaml, $(dtb-))
 endif
 
+# Test self-contained headers
+
+# Wildcard searches in $(srctree)/$(src)/, but not in $(objtree)/$(obj)/.
+# Stale generated headers are often left over, so pattern matching should
+# be avoided. Please notice $(srctree)/$(src)/ and $(objtree)/$(obj) point
+# to the same location for in-tree building. So, header-test-pattern-y should
+# be used with care.
+header-test-y	+= $(filter-out $(header-test-), \
+		$(patsubst $(srctree)/$(src)/%, %, \
+		$(wildcard $(addprefix $(srctree)/$(src)/, \
+		$(header-test-pattern-y)))))
+
+extra-$(CONFIG_HEADER_TEST) += $(addsuffix .s, $(header-test-y))
+
 # Add subdir path
 
 extra-y		:= $(addprefix $(obj)/,$(extra-y))
@@ -140,7 +154,7 @@ endif
 # $(srctree)/$(src) for including checkin headers from generated source files
 # $(objtree)/$(obj) for including generated headers from checkin source files
 ifeq ($(KBUILD_EXTMOD),)
-ifneq ($(srctree),.)
+ifdef building_out_of_srctree
 _c_flags   += -I $(srctree)/$(src) -I $(objtree)/$(obj)
 _a_flags   += -I $(srctree)/$(src) -I $(objtree)/$(obj)
 _cpp_flags += -I $(srctree)/$(src) -I $(objtree)/$(obj)
@@ -331,19 +345,19 @@ printf "%08x\n" $$dec_size |						\
 )
 
 quiet_cmd_bzip2 = BZIP2   $@
-      cmd_bzip2 = { cat $(real-prereqs) | bzip2 -9 && $(size_append); } > $@
+      cmd_bzip2 = { cat $(real-prereqs) | bzip2 -9; $(size_append); } > $@
 
 # Lzma
 # ---------------------------------------------------------------------------
 
 quiet_cmd_lzma = LZMA    $@
-      cmd_lzma = { cat $(real-prereqs) | lzma -9 && $(size_append); } > $@
+      cmd_lzma = { cat $(real-prereqs) | lzma -9; $(size_append); } > $@
 
 quiet_cmd_lzo = LZO     $@
-      cmd_lzo = { cat $(real-prereqs) | lzop -9 && $(size_append); } > $@
+      cmd_lzo = { cat $(real-prereqs) | lzop -9; $(size_append); } > $@
 
 quiet_cmd_lz4 = LZ4     $@
-      cmd_lz4 = { cat $(real-prereqs) | lz4c -l -c1 stdin stdout && \
+      cmd_lz4 = { cat $(real-prereqs) | lz4c -l -c1 stdin stdout; \
                   $(size_append); } > $@
 
 # U-Boot mkimage
@@ -386,7 +400,7 @@ quiet_cmd_uimage = UIMAGE  $@
 # big dictionary would increase the memory usage too much in the multi-call
 # decompression mode. A BCJ filter isn't used either.
 quiet_cmd_xzkern = XZKERN  $@
-      cmd_xzkern = { cat $(real-prereqs) | sh $(srctree)/scripts/xz_wrap.sh && \
+      cmd_xzkern = { cat $(real-prereqs) | sh $(srctree)/scripts/xz_wrap.sh; \
                      $(size_append); } > $@
 
 quiet_cmd_xzmisc = XZMISC  $@

scripts/Makefile.modbuiltin

@@ -15,7 +15,7 @@ include include/config/tristate.conf
 
 include scripts/Kbuild.include
 
-ifneq ($(srctree),.)
+ifdef building_out_of_srctree
 # Create output directory if not already present
 _dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
 endif

scripts/basic/fixdep.c

@@ -99,6 +99,7 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <string.h>
+#include <stdarg.h>
 #include <stdlib.h>
 #include <stdio.h>
 #include <ctype.h>
@@ -109,6 +110,36 @@ static void usage(void)
 	exit(1);
 }
 
+/*
+ * In the intended usage of this program, the stdout is redirected to .*.cmd
+ * files. The return value of printf() and putchar() must be checked to catch
+ * any error, e.g. "No space left on device".
+ */
+static void xprintf(const char *format, ...)
+{
+	va_list ap;
+	int ret;
+
+	va_start(ap, format);
+	ret = vprintf(format, ap);
+	if (ret < 0) {
+		perror("fixdep");
+		exit(1);
+	}
+	va_end(ap);
+}
+
+static void xputchar(int c)
+{
+	int ret;
+
+	ret = putchar(c);
+	if (ret == EOF) {
+		perror("fixdep");
+		exit(1);
+	}
+}
+
 /*
  * Print out a dependency path from a symbol name
  */
@@ -116,7 +147,7 @@ static void print_dep(const char *m, int slen, const char *dir)
 {
 	int c, prev_c = '/', i;
 
-	printf("    $(wildcard %s/", dir);
+	xprintf("    $(wildcard %s/", dir);
 	for (i = 0; i < slen; i++) {
 		c = m[i];
 		if (c == '_')
@@ -124,10 +155,10 @@ static void print_dep(const char *m, int slen, const char *dir)
 		else
 			c = tolower(c);
 		if (c != '/' || prev_c != '/')
-			putchar(c);
+			xputchar(c);
 		prev_c = c;
 	}
-	printf(".h) \\\n");
+	xprintf(".h) \\\n");
 }
 
 struct item {
@@ -324,13 +355,13 @@ static void parse_dep_file(char *m, const char *target)
 				 */
 				if (!saw_any_target) {
 					saw_any_target = 1;
-					printf("source_%s := %s\n\n",
-					       target, m);
-					printf("deps_%s := \\\n", target);
+					xprintf("source_%s := %s\n\n",
+						target, m);
+					xprintf("deps_%s := \\\n", target);
 				}
 				is_first_dep = 0;
 			} else {
-				printf("  %s \\\n", m);
+				xprintf("  %s \\\n", m);
 			}
 
 			buf = read_file(m);
@@ -353,8 +384,8 @@ static void parse_dep_file(char *m, const char *target)
 		exit(1);
 	}
 
-	printf("\n%s: $(deps_%s)\n\n", target, target);
-	printf("$(deps_%s):\n", target);
+	xprintf("\n%s: $(deps_%s)\n\n", target, target);
+	xprintf("$(deps_%s):\n", target);
 }
 
 int main(int argc, char *argv[])
@@ -369,7 +400,7 @@ int main(int argc, char *argv[])
 	target = argv[2];
 	cmdline = argv[3];
 
-	printf("cmd_%s := %s\n\n", target, cmdline);
+	xprintf("cmd_%s := %s\n\n", target, cmdline);
 
 	buf = read_file(depfile);
 	parse_dep_file(buf, target);

scripts/coccinelle/api/kstrdup.cocci

@@ -77,7 +77,7 @@ p1 << r1.p1;
 p2 << r1.p2;
 @@
 
-cocci.print_main("WARNING opportunity for kstrdep",p1)
+cocci.print_main("WARNING opportunity for kstrdup",p1)
 cocci.print_secs("strcpy",p2)
 
 @script:python depends on org@
@@ -85,7 +85,7 @@ p1 << r2.p1;
 p2 << r2.p2;
 @@
 
-cocci.print_main("WARNING opportunity for kstrdep",p1)
+cocci.print_main("WARNING opportunity for kstrdup",p1)
 cocci.print_secs("memcpy",p2)
 
 @script:python depends on report@
@@ -93,7 +93,7 @@ p1 << r1.p1;
 p2 << r1.p2;
 @@
 
-msg = "WARNING opportunity for kstrdep (strcpy on line %s)" % (p2[0].line)
+msg = "WARNING opportunity for kstrdup (strcpy on line %s)" % (p2[0].line)
 coccilib.report.print_report(p1[0], msg)
 
 @script:python depends on report@
@@ -101,5 +101,5 @@ p1 << r2.p1;
 p2 << r2.p2;
 @@
 
-msg = "WARNING opportunity for kstrdep (memcpy on line %s)" % (p2[0].line)
+msg = "WARNING opportunity for kstrdup (memcpy on line %s)" % (p2[0].line)
 coccilib.report.print_report(p1[0], msg)

scripts/coccinelle/api/stream_open.cocci

@@ -35,11 +35,11 @@ type loff_t;
 // a function that blocks
 @ blocks @
 identifier block_f;
-identifier wait_event =~ "^wait_event_.*";
+identifier wait =~ "^wait_.*";
 @@
   block_f(...) {
     ... when exists
-    wait_event(...)
+    wait(...)
     ... when exists
   }
 
@@ -49,12 +49,12 @@ identifier wait_event =~ "^wait_event_.*";
 // XXX currently reader_blocks supports only direct and 1-level indirect cases.
 @ reader_blocks_direct @
 identifier stream_reader.readstream;
-identifier wait_event =~ "^wait_event_.*";
+identifier wait =~ "^wait_.*";
 @@
   readstream(...)
   {
     ... when exists
-    wait_event(...)
+    wait(...)
     ... when exists
   }
 

scripts/coccinelle/free/put_device.cocci

@@ -24,7 +24,7 @@ if (id == NULL || ...) { ... return ...; }
     when != of_dev_put(id)
     when != if (id) { ... put_device(&id->dev) ... }
     when != e1 = (T)id
-    when != e1 = &id->dev
+    when != e1 = (T)(&id->dev)
     when != e1 = get_device(&id->dev)
     when != e1 = (T1)platform_get_drvdata(id)
 (
@@ -42,11 +42,10 @@ p1 << search.p1;
 p2 << search.p2;
 @@
 
-coccilib.report.print_report(p2[0], "ERROR: missing put_device; "
-			      + "call of_find_device_by_node on line "
-			      + p1[0].line
-			      + ", but without a corresponding object release "
-			      + "within this function.")
+coccilib.report.print_report(p2[0],
+                             "ERROR: missing put_device; call of_find_device_by_node on line "
+                             + p1[0].line
+                             + ", but without a corresponding object release within this function.")
 
 @script:python depends on org@
 p1 << search.p1;

scripts/gdb/linux/Makefile

 # SPDX-License-Identifier: GPL-2.0
 
-ifneq ($(srctree),.)
+ifdef building_out_of_srctree
 
 symlinks := $(patsubst $(srctree)/$(src)/%,%,$(wildcard $(srctree)/$(src)/*.py))
 

scripts/genksyms/keywords.c

@@ -25,6 +25,10 @@ static struct resword {
 	{ "__volatile__", VOLATILE_KEYW },
 	{ "__builtin_va_list", VA_LIST_KEYW },
 
+	{ "__int128", BUILTIN_INT_KEYW },
+	{ "__int128_t", BUILTIN_INT_KEYW },
+	{ "__uint128_t", BUILTIN_INT_KEYW },
+
 	// According to rth, c99 defines "_Bool", __restrict", __restrict__", "restrict".  KAO
 	{ "_Bool", BOOL_KEYW },
 	{ "_restrict", RESTRICT_KEYW },

scripts/genksyms/parse.y

@@ -76,6 +76,7 @@ static void record_compound(struct string_list **keyw,
 %token ATTRIBUTE_KEYW
 %token AUTO_KEYW
 %token BOOL_KEYW
+%token BUILTIN_INT_KEYW
 %token CHAR_KEYW
 %token CONST_KEYW
 %token DOUBLE_KEYW
@@ -263,6 +264,7 @@ simple_type_specifier:
 	| VOID_KEYW
 	| BOOL_KEYW
 	| VA_LIST_KEYW
+	| BUILTIN_INT_KEYW
 	| TYPE			{ (*$1)->tag = SYM_TYPEDEF; $$ = $1; }
 	;
 

scripts/headers.sh

-#!/bin/sh
-# SPDX-License-Identifier: GPL-2.0
-# Run headers_$1 command for all suitable architectures
-
-# Stop on error
-set -e
-
-do_command()
-{
-	if [ -f ${srctree}/arch/$2/include/asm/Kbuild ]; then
-		make ARCH=$2 KBUILD_HEADERS=$1 headers_$1
-	else
-		printf "Ignoring arch: %s\n" ${arch}
-	fi
-}
-
-archs=${HDR_ARCH_LIST:-$(ls ${srctree}/arch)}
-
-for arch in ${archs}; do
-	case ${arch} in
-	um)        # no userspace export
-		;;
-	*)
-		if [ -d ${srctree}/arch/${arch} ]; then
-			do_command $1 ${arch}
-		fi
-		;;
-	esac
-done

scripts/headers_install.sh

 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
 
-if [ $# -lt 2 ]
+if [ $# -ne 2 ]
 then
-	echo "Usage: headers_install.sh OUTDIR SRCDIR [FILES...]"
+	echo "Usage: headers_install.sh INFILE OUTFILE"
 	echo
 	echo "Prepares kernel header files for use by user space, by removing"
 	echo "all compiler.h definitions and #includes, removing any"
 	echo "#ifdef __KERNEL__ sections, and putting __underscores__ around"
 	echo "asm/inline/volatile keywords."
 	echo
-	echo "OUTDIR: directory to write each userspace header FILE to."
-	echo "SRCDIR: source directory where files are picked."
-	echo "FILES:  list of header files to operate on."
+	echo "INFILE: header file to operate on"
+	echo "OUTFILE: output file which the processed header is writen to"
 
 	exit 1
 fi
 
 # Grab arguments
+INFILE=$1
+OUTFILE=$2
+TMPFILE=$OUTFILE.tmp
 
-OUTDIR="$1"
-shift
-SRCDIR="$1"
-shift
+trap 'rm -f $OUTFILE $TMPFILE' EXIT
 
-# Iterate through files listed on command line
+sed -E -e '
+	s/([[:space:](])(__user|__force|__iomem)[[:space:]]/\1/g
+	s/__attribute_const__([[:space:]]|$)/\1/g
+	s@^#include <linux/compiler(|_types).h>@@
+	s/(^|[^a-zA-Z0-9])__packed([^a-zA-Z0-9_]|$)/\1__attribute__((packed))\2/g
+	s/(^|[[:space:](])(inline|asm|volatile)([[:space:](]|$)/\1__\2__\3/g
+	s@#(ifndef|define|endif[[:space:]]*/[*])[[:space:]]*_UAPI@#\1 @
+' $INFILE > $TMPFILE || exit 1
 
-FILE=
-trap 'rm -f "$OUTDIR/$FILE" "$OUTDIR/$FILE.sed"' EXIT
-for i in "$@"
-do
-	FILE="$(basename "$i")"
-	sed -E \
-		-e 's/([[:space:](])(__user|__force|__iomem)[[:space:]]/\1/g' \
-		-e 's/__attribute_const__([[:space:]]|$)/\1/g' \
-		-e 's@^#include <linux/compiler(|_types).h>@@' \
-		-e 's/(^|[^a-zA-Z0-9])__packed([^a-zA-Z0-9_]|$)/\1__attribute__((packed))\2/g' \
-		-e 's/(^|[[:space:](])(inline|asm|volatile)([[:space:](]|$)/\1__\2__\3/g' \
-		-e 's@#(ifndef|define|endif[[:space:]]*/[*])[[:space:]]*_UAPI@#\1 @' \
-		"$SRCDIR/$i" > "$OUTDIR/$FILE.sed" || exit 1
-	scripts/unifdef -U__KERNEL__ -D__EXPORTED_HEADERS__ "$OUTDIR/$FILE.sed" \
-		> "$OUTDIR/$FILE"
-	[ $? -gt 1 ] && exit 1
-	rm -f "$OUTDIR/$FILE.sed"
-done
+scripts/unifdef -U__KERNEL__ -D__EXPORTED_HEADERS__ $TMPFILE > $OUTFILE
+[ $? -gt 1 ] && exit 1
+
+rm -f $TMPFILE
 trap - EXIT

scripts/kallsyms.c

@@ -150,6 +150,9 @@ static int read_symbol(FILE *in, struct sym_entry *s)
 	/* exclude debugging symbols */
 	else if (stype == 'N' || stype == 'n')
 		return -1;
+	/* exclude s390 kasan local symbols */
+	else if (!strncmp(sym, ".LASANPC", 8))
+		return -1;
 
 	/* include the type field in the symbol name, so that it gets
 	 * compressed together */

scripts/package/builddeb

@@ -130,7 +130,7 @@ if is_enabled CONFIG_MODULES; then
 fi
 
 if [ "$ARCH" != "um" ]; then
-	$MAKE -f $srctree/Makefile headers_check
+	$MAKE -f $srctree/Makefile headers
 	$MAKE -f $srctree/Makefile headers_install INSTALL_HDR_PATH="$libc_headers_dir/usr"
 fi
 

scripts/package/mkspec

@@ -31,7 +31,7 @@ PROVIDES="$PROVIDES kernel-$KERNELRELEASE"
 __KERNELRELEASE=$(echo $KERNELRELEASE | sed -e "s/-/_/g")
 EXCLUDES="$RCS_TAR_IGNORE --exclude=.tmp_versions --exclude=*vmlinux* \
 --exclude=*.o --exclude=*.ko --exclude=*.cmd --exclude=Documentation \
---exclude=.config.old --exclude=.missing-syscalls.d"
+--exclude=.config.old --exclude=.missing-syscalls.d --exclude=*.s"
 
 # We can label the here-doc lines for conditional output to the spec file
 #

scripts/tags.sh

@@ -6,7 +6,7 @@
 # mode may be any of: tags, TAGS, cscope
 #
 # Uses the following environment variables:
-# ARCH, SUBARCH, SRCARCH, srctree, src, obj
+# SUBARCH, SRCARCH, srctree
 
 if [ "$KBUILD_VERBOSE" = "1" ]; then
 	set -x
@@ -17,8 +17,7 @@ ignore="$(echo "$RCS_FIND_IGNORE" | sed 's|\\||g' )"
 # tags and cscope files should also ignore MODVERSION *.mod.c files
 ignore="$ignore ( -name *.mod.c ) -prune -o"
 
-# Do not use full path if we do not use O=.. builds
-# Use make O=. {tags|cscope}
+# Use make KBUILD_ABS_SRCTREE=1 {tags|cscope}
 # to force full paths for a non-O= build
 if [ "${srctree}" = "." -o -z "${srctree}" ]; then
 	tree=
@@ -36,21 +35,19 @@ elif [ "${ALLSOURCE_ARCHS}" = "all" ]; then
 	ALLSOURCE_ARCHS=$(find ${tree}arch/ -mindepth 1 -maxdepth 1 -type d -printf '%f ')
 fi
 
-# find sources in arch/$ARCH
+# find sources in arch/$1
 find_arch_sources()
 {
 	for i in $archincludedir; do
 		prune="$prune -wholename $i -prune -o"
 	done
-	find ${tree}arch/$1 $ignore $subarchprune $prune -name "$2" \
-		-not -type l -print;
+	find ${tree}arch/$1 $ignore $prune -name "$2" -not -type l -print;
 }
 
 # find sources in arch/$1/include
 find_arch_include_sources()
 {
-	include=$(find ${tree}arch/$1/ $subarchprune \
-					-name include -type d -print);
+	include=$(find ${tree}arch/$1/ -name include -type d -print);
 	if [ -n "$include" ]; then
 		archincludedir="$archincludedir $include"
 		find $include $ignore -name "$2" -not -type l -print;
@@ -306,36 +303,6 @@ if [ "${ARCH}" = "um" ]; then
 	else
 		archinclude=${SUBARCH}
 	fi
-elif [ "${SRCARCH}" = "arm" -a "${SUBARCH}" != "" ]; then
-	subarchdir=$(find ${tree}arch/$SRCARCH/ -name "mach-*" -type d -o \
-							-name "plat-*" -type d);
-	mach_suffix=$SUBARCH
-	plat_suffix=$SUBARCH
-
-	# Special cases when $plat_suffix != $mach_suffix
-	case $mach_suffix in
-		"omap1" | "omap2")
-			plat_suffix="omap"
-			;;
-	esac
-
-	if [ ! -d ${tree}arch/$SRCARCH/mach-$mach_suffix ]; then
-		echo "Warning: arch/arm/mach-$mach_suffix/ not found." >&2
-		echo "         Fix your \$SUBARCH appropriately" >&2
-	fi
-
-	for i in $subarchdir; do
-		case "$i" in
-			*"mach-"${mach_suffix})
-				;;
-			*"plat-"${plat_suffix})
-				;;
-			*)
-				subarchprune="$subarchprune \
-						-wholename $i -prune -o"
-				;;
-		esac
-	done
 fi
 
 remove_structs=

tools/testing/selftests/Makefile

@@ -74,7 +74,7 @@ endif
 # Append kselftest to KBUILD_OUTPUT to avoid cluttering
 # KBUILD_OUTPUT with selftest objects and headers installed
 # by selftests Makefile or lib.mk.
-ifneq ($(KBUILD_SRC),)
+ifdef building_out_of_srctree
 override LDFLAGS =
 endif
 

tools/testing/selftests/lib.mk

@@ -70,7 +70,7 @@ define RUN_TESTS
 endef
 
 run_tests: all
-ifneq ($(KBUILD_SRC),)
+ifdef building_out_of_srctree
 	@if [ "X$(TEST_PROGS) $(TEST_PROGS_EXTENDED) $(TEST_FILES)" != "X" ]; then
 		@rsync -aq $(TEST_PROGS) $(TEST_PROGS_EXTENDED) $(TEST_FILES) $(OUTPUT)
 	fi
@@ -125,7 +125,7 @@ clean:
 # When make O= with kselftest target from main level
 # the following aren't defined.
 #
-ifneq ($(KBUILD_SRC),)
+ifdef building_out_of_srctree
 LINK.c = $(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) $(TARGET_ARCH)
 COMPILE.S = $(CC) $(ASFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c
 LINK.S = $(CC) $(ASFLAGS) $(CPPFLAGS) $(LDFLAGS) $(TARGET_ARCH)

usr/.gitignore

@@ -7,4 +7,3 @@ initramfs_data.cpio.gz
 initramfs_data.cpio.bz2
 initramfs_data.cpio.lzma
 initramfs_list
-include

usr/Makefile

@@ -56,3 +56,5 @@ $(deps_initramfs): klibcdirs
 $(obj)/$(datafile_y): $(obj)/gen_init_cpio $(deps_initramfs) klibcdirs
 	$(Q)$(initramfs) -l $(ramfs-input) > $(obj)/$(datafile_d_y)
 	$(call if_changed,initfs)
+
+subdir-$(CONFIG_UAPI_HEADER_TEST) += include

usr/include/.gitignore

+*
+!.gitignore
+!Makefile

usr/include/Makefile

+# SPDX-License-Identifier: GPL-2.0-only
+
+# Unlike the kernel space, exported headers are written in standard C.
+#  - Forbid C++ style comments
+#  - Use '__inline__', '__asm__' instead of 'inline', 'asm'
+#
+# -std=c90 (equivalent to -ansi) catches the violation of those.
+# We cannot go as far as adding -Wpedantic since it emits too many warnings.
+UAPI_CFLAGS := -std=c90 -Wall -Werror=implicit-function-declaration
+
+override c_flags = $(UAPI_CFLAGS) -Wp,-MD,$(depfile) -I$(objtree)/usr/include
+
+# The following are excluded for now because they fail to build.
+#
+# Do not add a new header to the blacklist without legitimate reason.
+# Please consider to fix the header first.
+#
+# Sorted alphabetically.
+header-test- += asm/ipcbuf.h
+header-test- += asm/msgbuf.h
+header-test- += asm/sembuf.h
+header-test- += asm/shmbuf.h
+header-test- += asm/signal.h
+header-test- += asm/ucontext.h
+header-test- += drm/vmwgfx_drm.h
+header-test- += linux/am437x-vpfe.h
+header-test- += linux/android/binder.h
+header-test- += linux/android/binderfs.h
+header-test-$(CONFIG_CPU_BIG_ENDIAN) += linux/byteorder/big_endian.h
+header-test-$(CONFIG_CPU_LITTLE_ENDIAN) += linux/byteorder/little_endian.h
+header-test- += linux/coda.h
+header-test- += linux/coda_psdev.h
+header-test- += linux/dvb/audio.h
+header-test- += linux/dvb/osd.h
+header-test- += linux/elfcore.h
+header-test- += linux/errqueue.h
+header-test- += linux/fsmap.h
+header-test- += linux/hdlc/ioctl.h
+header-test- += linux/ivtv.h
+header-test- += linux/jffs2.h
+header-test- += linux/kexec.h
+header-test- += linux/matroxfb.h
+header-test- += linux/netfilter_bridge/ebtables.h
+header-test- += linux/netfilter_ipv4/ipt_LOG.h
+header-test- += linux/netfilter_ipv6/ip6t_LOG.h
+header-test- += linux/nfc.h
+header-test- += linux/nilfs2_ondisk.h
+header-test- += linux/omap3isp.h
+header-test- += linux/omapfb.h
+header-test- += linux/patchkey.h
+header-test- += linux/phonet.h
+header-test- += linux/reiserfs_xattr.h
+header-test- += linux/scc.h
+header-test- += linux/sctp.h
+header-test- += linux/signal.h
+header-test- += linux/sysctl.h
+header-test- += linux/usb/audio.h
+header-test- += linux/v4l2-mediabus.h
+header-test- += linux/v4l2-subdev.h
+header-test- += linux/videodev2.h
+header-test- += linux/vm_sockets.h
+header-test- += misc/ocxl.h
+header-test- += mtd/mtd-abi.h
+header-test- += mtd/mtd-user.h
+header-test- += scsi/scsi_bsg_fc.h
+header-test- += scsi/scsi_netlink.h
+header-test- += scsi/scsi_netlink_fc.h
+header-test- += sound/asequencer.h
+header-test- += sound/asoc.h
+header-test- += sound/asound.h
+header-test- += sound/compress_offload.h
+header-test- += sound/emu10k1.h
+header-test- += sound/sfnt_info.h
+header-test- += sound/sof/eq.h
+header-test- += sound/sof/fw.h
+header-test- += sound/sof/header.h
+header-test- += sound/sof/manifest.h
+header-test- += sound/sof/trace.h
+header-test- += xen/evtchn.h
+header-test- += xen/gntdev.h
+header-test- += xen/privcmd.h
+
+# More headers are broken in some architectures
+
+ifeq ($(SRCARCH),arc)
+header-test- += linux/bpf_perf_event.h
+endif
+
+ifeq ($(SRCARCH),ia64)
+header-test- += asm/setup.h
+header-test- += asm/sigcontext.h
+header-test- += asm/perfmon.h
+header-test- += asm/perfmon_default_smpl.h
+header-test- += linux/if_bonding.h
+endif
+
+ifeq ($(SRCARCH),mips)
+header-test- += asm/stat.h
+endif
+
+ifeq ($(SRCARCH),powerpc)
+header-test- += asm/stat.h
+header-test- += linux/bpf_perf_event.h
+endif
+
+ifeq ($(SRCARCH),riscv)
+header-test- += linux/bpf_perf_event.h
+endif
+
+ifeq ($(SRCARCH),s390)
+header-test- += asm/runtime_instr.h
+header-test- += asm/zcrypt.h
+endif
+
+ifeq ($(SRCARCH),sparc)
+header-test- += asm/stat.h
+header-test- += asm/uctx.h
+header-test- += asm/fbio.h
+header-test- += asm/openpromio.h
+endif
+
+# asm-generic/*.h is used by asm/*.h, and should not be included directly
+header-test- += asm-generic/%
+
+# The rest are compile-tested
+header-test-y += $(filter-out $(header-test-), \
+			$(patsubst $(obj)/%,%, $(wildcard \
+			$(addprefix $(obj)/, *.h */*.h */*/*.h */*/*/*.h))))
+
+# For GNU Make <= 4.2.1, $(wildcard $(obj)/*/) matches to not only directories
+# but also regular files. Use $(filter %/, ...) just in case.
+clean-dirs += $(patsubst $(obj)/%/,%,$(filter %/, $(wildcard $(obj)/*/)))