Merge tag 'kbuild-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - add modpost warn exported symbols marked as 'static' because 'static'
   and EXPORT_SYMBOL is an odd combination

 - break the build early if gold linker is used

 - optimize the Bison rule to produce .c and .h files by a single
   pattern rule

 - handle PREEMPT_RT in the module vermagic and UTS_VERSION

 - warn CONFIG options leaked to the user-space except existing ones

 - make single targets work properly

 - rebuild modules when module linker scripts are updated

 - split the module final link stage into scripts/Makefile.modfinal

 - fix the missed error code in merge_config.sh

 - improve the error message displayed on the attempt of the O= build in
   unclean source tree

 - remove 'clean-dirs' syntax

 - disable -Wimplicit-fallthrough warning for Clang

 - add CONFIG_CC_OPTIMIZE_FOR_SIZE_O3 for ARC

 - remove ARCH_{CPP,A,C}FLAGS variables

 - add $(BASH) to run bash scripts

 - change *CFLAGS_<basetarget>.o to take the relative path to $(obj)
   instead of the basename

 - stop suppressing Clang's -Wunused-function warnings when W=1

 - fix linux/export.h to avoid genksyms calculating CRC of trimmed
   exported symbols

 - misc cleanups

* tag 'kbuild-v5.4' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (63 commits)
  genksyms: convert to SPDX License Identifier for lex.l and parse.y
  modpost: use __section in the output to *.mod.c
  modpost: use MODULE_INFO() for __module_depends
  export.h, genksyms: do not make genksyms calculate CRC of trimmed symbols
  export.h: remove defined(__KERNEL__), which is no longer needed
  kbuild: allow Clang to find unused static inline functions for W=1 build
  kbuild: rename KBUILD_ENABLE_EXTRA_GCC_CHECKS to KBUILD_EXTRA_WARN
  kbuild: refactor scripts/Makefile.extrawarn
  merge_config.sh: ignore unwanted grep errors
  kbuild: change *FLAGS_<basetarget>.o to take the path relative to $(obj)
  modpost: add NOFAIL to strndup
  modpost: add guid_t type definition
  kbuild: add $(BASH) to run scripts with bash-extension
  kbuild: remove ARCH_{CPP,A,C}FLAGS
  kbuild,arc: add CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3 for ARC
  kbuild: Do not enable -Wimplicit-fallthrough for clang for now
  kbuild: clean up subdir-ymn calculation in Makefile.clean
  kbuild: remove unneeded '+' marker from cmd_clean
  kbuild: remove clean-dirs syntax
  kbuild: check clean srctree even earlier
  ...

1 files changed, 151 insertions, 145 deletions

diff --git a/Makefile b/Makefile
index 2fa7cfa6fca3..656a8c95789d 100644
--- a/Makefile
+++ b/Makefile
@@ -230,6 +230,8 @@ endif
 
 export KBUILD_CHECKSRC KBUILD_EXTMOD
 
+extmod-prefix = $(if $(KBUILD_EXTMOD),$(KBUILD_EXTMOD)/)
+
 ifeq ($(abs_srctree),$(abs_objtree))
         # building in the source tree
         srctree := .
@@ -271,52 +273,62 @@ no-dot-config-targets := $(clean-targets) \
 			 %asm-generic kernelversion %src-pkg
 no-sync-config-targets := $(no-dot-config-targets) install %install \
 			   kernelrelease
+single-targets := %.a %.i %.ko %.lds %.ll %.lst %.mod %.o %.s %.symtypes %/
 
-config-targets  := 0
-mixed-targets   := 0
-dot-config      := 1
-may-sync-config := 1
+config-build	:=
+mixed-build	:=
+need-config	:= 1
+may-sync-config	:= 1
+single-build	:=
 
 ifneq ($(filter $(no-dot-config-targets), $(MAKECMDGOALS)),)
 	ifeq ($(filter-out $(no-dot-config-targets), $(MAKECMDGOALS)),)
-		dot-config := 0
+		need-config :=
 	endif
 endif
 
 ifneq ($(filter $(no-sync-config-targets), $(MAKECMDGOALS)),)
 	ifeq ($(filter-out $(no-sync-config-targets), $(MAKECMDGOALS)),)
-		may-sync-config := 0
+		may-sync-config :=
 	endif
 endif
 
 ifneq ($(KBUILD_EXTMOD),)
-	may-sync-config := 0
+	may-sync-config :=
 endif
 
 ifeq ($(KBUILD_EXTMOD),)
         ifneq ($(filter config %config,$(MAKECMDGOALS)),)
-                config-targets := 1
+		config-build := 1
                 ifneq ($(words $(MAKECMDGOALS)),1)
-                        mixed-targets := 1
+			mixed-build := 1
                 endif
         endif
 endif
 
+# We cannot build single targets and the others at the same time
+ifneq ($(filter $(single-targets), $(MAKECMDGOALS)),)
+	single-build := 1
+	ifneq ($(filter-out $(single-targets), $(MAKECMDGOALS)),)
+		mixed-build := 1
+	endif
+endif
+
 # For "make -j clean all", "make -j mrproper defconfig all", etc.
 ifneq ($(filter $(clean-targets),$(MAKECMDGOALS)),)
         ifneq ($(filter-out $(clean-targets),$(MAKECMDGOALS)),)
-                mixed-targets := 1
+		mixed-build := 1
         endif
 endif
 
 # install and modules_install need also be processed one by one
 ifneq ($(filter install,$(MAKECMDGOALS)),)
         ifneq ($(filter modules_install,$(MAKECMDGOALS)),)
-	        mixed-targets := 1
+		mixed-build := 1
         endif
 endif
 
-ifeq ($(mixed-targets),1)
+ifdef mixed-build
 # ===========================================================================
 # We're called with mixed targets (*config and build targets).
 # Handle them one by one.
@@ -332,7 +344,7 @@ __build_one_by_one:
 		$(MAKE) -f $(srctree)/Makefile $$i; \
 	done
 
-else
+else # !mixed-build
 
 include scripts/Kbuild.include
 
@@ -392,9 +404,7 @@ KCONFIG_CONFIG	?= .config
 export KCONFIG_CONFIG
 
 # SHELL used by kbuild
-CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \
-	  else if [ -x /bin/bash ]; then echo /bin/bash; \
-	  else echo sh; fi ; fi)
+CONFIG_SHELL := sh
 
 HOST_LFS_CFLAGS := $(shell getconf LFS_CFLAGS 2>/dev/null)
 HOST_LFS_LDFLAGS := $(shell getconf LFS_LDFLAGS 2>/dev/null)
@@ -431,6 +441,7 @@ PYTHON		= python
 PYTHON2		= python2
 PYTHON3		= python3
 CHECK		= sparse
+BASH		= bash
 
 CHECKFLAGS     := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \
 		  -Wbitwise -Wno-return-void -Wno-unknown-attribute $(CF)
@@ -470,12 +481,13 @@ KBUILD_AFLAGS_KERNEL :=
 KBUILD_CFLAGS_KERNEL :=
 KBUILD_AFLAGS_MODULE  := -DMODULE
 KBUILD_CFLAGS_MODULE  := -DMODULE
-KBUILD_LDFLAGS_MODULE := -T $(srctree)/scripts/module-common.lds
+KBUILD_LDFLAGS_MODULE :=
+export KBUILD_LDS_MODULE := $(srctree)/scripts/module-common.lds
 KBUILD_LDFLAGS :=
 GCC_PLUGINS_CFLAGS :=
 CLANG_FLAGS :=
 
-export ARCH SRCARCH CONFIG_SHELL HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE AS LD CC
+export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE AS LD CC
 export CPP AR NM STRIP OBJCOPY OBJDUMP OBJSIZE PAHOLE LEX YACC AWK INSTALLKERNEL
 export PERL PYTHON PYTHON2 PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
 export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE
@@ -506,6 +518,7 @@ scripts_basic:
 	$(Q)rm -f .tmp_quiet_recordmcount
 
 PHONY += outputmakefile
+# Before starting out-of-tree build, make sure the source tree is clean.
 # outputmakefile generates a Makefile in the output directory, if using a
 # separate output directory. This allows convenient use of make in the
 # output directory.
@@ -513,6 +526,15 @@ PHONY += outputmakefile
 # ignore whole output directory
 outputmakefile:
 ifdef building_out_of_srctree
+	$(Q)if [ -f $(srctree)/.config -o \
+		 -d $(srctree)/include/config -o \
+		 -d $(srctree)/arch/$(SRCARCH)/include/generated ]; then \
+		echo >&2 "***"; \
+		echo >&2 "*** The source tree is not clean, please run 'make$(if $(findstring command line, $(origin ARCH)), ARCH=$(ARCH)) mrproper'"; \
+		echo >&2 "*** in $(abs_srctree)";\
+		echo >&2 "***"; \
+		false; \
+	fi
 	$(Q)ln -fsn $(srctree) source
 	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile $(srctree)
 	$(Q)test -e .gitignore || \
@@ -544,7 +566,7 @@ endif
 # and from include/config/auto.conf.cmd to detect the compiler upgrade.
 CC_VERSION_TEXT = $(shell $(CC) --version 2>/dev/null | head -n 1)
 
-ifeq ($(config-targets),1)
+ifdef config-build
 # ===========================================================================
 # *config targets only - make sure prerequisites are updated, and descend
 # in scripts/kconfig to make the *config target
@@ -555,13 +577,13 @@ ifeq ($(config-targets),1)
 include arch/$(SRCARCH)/Makefile
 export KBUILD_DEFCONFIG KBUILD_KCONFIG CC_VERSION_TEXT
 
-config: scripts_basic outputmakefile FORCE
+config: outputmakefile scripts_basic FORCE
 	$(Q)$(MAKE) $(build)=scripts/kconfig $@
 
-%config: scripts_basic outputmakefile FORCE
+%config: outputmakefile scripts_basic FORCE
 	$(Q)$(MAKE) $(build)=scripts/kconfig $@
 
-else
+else #!config-build
 # ===========================================================================
 # Build targets only - this includes vmlinux, arch specific targets, clean
 # targets and others. In general all targets except *config targets.
@@ -604,7 +626,7 @@ endif
 
 export KBUILD_MODULES KBUILD_BUILTIN
 
-ifeq ($(dot-config),1)
+ifdef need-config
 include include/config/auto.conf
 endif
 
@@ -645,15 +667,10 @@ RETPOLINE_VDSO_CFLAGS := $(call cc-option,$(RETPOLINE_VDSO_CFLAGS_GCC),$(call cc
 export RETPOLINE_CFLAGS
 export RETPOLINE_VDSO_CFLAGS
 
-# The arch Makefile can set ARCH_{CPP,A,C}FLAGS to override the default
-# values of the respective KBUILD_* variables
-ARCH_CPPFLAGS :=
-ARCH_AFLAGS :=
-ARCH_CFLAGS :=
 include arch/$(SRCARCH)/Makefile
 
-ifeq ($(dot-config),1)
-ifeq ($(may-sync-config),1)
+ifdef need-config
+ifdef may-sync-config
 # Read in dependencies to all Kconfig* files, make sure to run syncconfig if
 # changes are detected. This should be included after arch/$(SRCARCH)/Makefile
 # because some architectures define CROSS_COMPILE there.
@@ -676,7 +693,7 @@ $(KCONFIG_CONFIG):
 # The syncconfig should be executed only once to make all the targets.
 %/auto.conf %/auto.conf.cmd %/tristate.conf: $(KCONFIG_CONFIG)
 	$(Q)$(MAKE) -f $(srctree)/Makefile syncconfig
-else
+else # !may-sync-config
 # External modules and some install targets need include/generated/autoconf.h
 # and include/config/auto.conf but do not care if they are up-to-date.
 # Use auto.conf to trigger the test
@@ -692,7 +709,7 @@ include/config/auto.conf:
 	/bin/false)
 
 endif # may-sync-config
-endif # $(dot-config)
+endif # need-config
 
 KBUILD_CFLAGS	+= $(call cc-option,-fno-delete-null-pointer-checks,)
 KBUILD_CFLAGS	+= $(call cc-disable-warning,frame-address,)
@@ -700,10 +717,12 @@ KBUILD_CFLAGS	+= $(call cc-disable-warning, format-truncation)
 KBUILD_CFLAGS	+= $(call cc-disable-warning, format-overflow)
 KBUILD_CFLAGS	+= $(call cc-disable-warning, address-of-packed-member)
 
-ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
-KBUILD_CFLAGS	+= -Os
-else
-KBUILD_CFLAGS   += -O2
+ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE
+KBUILD_CFLAGS += -O2
+else ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE_O3
+KBUILD_CFLAGS += -O3
+else ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
+KBUILD_CFLAGS += -Os
 endif
 
 ifdef CONFIG_CC_DISABLE_WARN_MAYBE_UNINITIALIZED
@@ -751,6 +770,11 @@ else
 # These warnings generated too much noise in a regular build.
 # Use make W=1 to enable them (see scripts/Makefile.extrawarn)
 KBUILD_CFLAGS += -Wno-unused-but-set-variable
+
+# Warn about unmarked fall-throughs in switch statement.
+# Disabled for clang while comment to attribute conversion happens and
+# https://github.com/ClangBuiltLinux/linux/issues/636 is discussed.
+KBUILD_CFLAGS += $(call cc-option,-Wimplicit-fallthrough,)
 endif
 
 KBUILD_CFLAGS += $(call cc-disable-warning, unused-const-variable)
@@ -845,9 +869,6 @@ NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
 # warn about C99 declaration after statement
 KBUILD_CFLAGS += -Wdeclaration-after-statement
 
-# Warn about unmarked fall-throughs in switch statement.
-KBUILD_CFLAGS += $(call cc-option,-Wimplicit-fallthrough,)
-
 # Variable Length Arrays (VLAs) should not be used anywhere in the kernel
 KBUILD_CFLAGS += -Wvla
 
@@ -900,11 +921,10 @@ include scripts/Makefile.kasan
 include scripts/Makefile.extrawarn
 include scripts/Makefile.ubsan
 
-# Add any arch overrides and user supplied CPPFLAGS, AFLAGS and CFLAGS as the
-# last assignments
-KBUILD_CPPFLAGS += $(ARCH_CPPFLAGS) $(KCPPFLAGS)
-KBUILD_AFLAGS   += $(ARCH_AFLAGS)   $(KAFLAGS)
-KBUILD_CFLAGS   += $(ARCH_CFLAGS)   $(KCFLAGS)
+# Add user supplied CPPFLAGS, AFLAGS and CFLAGS as the last assignments
+KBUILD_CPPFLAGS += $(KCPPFLAGS)
+KBUILD_AFLAGS   += $(KAFLAGS)
+KBUILD_CFLAGS   += $(KCFLAGS)
 
 KBUILD_LDFLAGS_MODULE += --build-id
 LDFLAGS_vmlinux += --build-id
@@ -1007,7 +1027,7 @@ endif
 
 PHONY += prepare0
 
-export MODORDER := $(if $(KBUILD_EXTMOD),$(KBUILD_EXTMOD)/)modules.order
+export MODORDER := $(extmod-prefix)modules.order
 
 ifeq ($(KBUILD_EXTMOD),)
 core-y		+= kernel/ certs/ mm/ fs/ ipc/ security/ crypto/ block/
@@ -1020,6 +1040,9 @@ vmlinux-alldirs	:= $(sort $(vmlinux-dirs) Documentation \
 		     $(patsubst %/,%,$(filter %/, $(init-) $(core-) \
 			$(drivers-) $(net-) $(libs-) $(virt-))))
 
+build-dirs	:= $(vmlinux-dirs)
+clean-dirs	:= $(vmlinux-alldirs)
+
 init-y		:= $(patsubst %/, %/built-in.a, $(init-y))
 core-y		:= $(patsubst %/, %/built-in.a, $(core-y))
 drivers-y	:= $(patsubst %/, %/built-in.a, $(drivers-y))
@@ -1042,7 +1065,7 @@ vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)
 # Recurse until adjust_autoksyms.sh is satisfied
 PHONY += autoksyms_recursive
 ifdef CONFIG_TRIM_UNUSED_KSYMS
-autoksyms_recursive: $(vmlinux-deps) modules.order
+autoksyms_recursive: descend modules.order
 	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/adjust_autoksyms.sh \
 	  "$(MAKE) -f $(srctree)/Makefile vmlinux"
 endif
@@ -1074,17 +1097,7 @@ targets := vmlinux
 
 # The actual objects are generated when descending,
 # make sure no implicit rule kicks in
-$(sort $(vmlinux-deps)): $(vmlinux-dirs) ;
-
-# Handle descending into subdirectories listed in $(vmlinux-dirs)
-# Preset locale variables to speed up the build process. Limit locale
-# tweaks to this spot to avoid wrong language settings when running
-# make menuconfig etc.
-# Error messages still appears in the original language
-
-PHONY += $(vmlinux-dirs)
-$(vmlinux-dirs): prepare
-	$(Q)$(MAKE) $(build)=$@ need-builtin=1 need-modorder=1
+$(sort $(vmlinux-deps)): descend ;
 
 filechk_kernel.release = \
 	echo "$(KERNELVERSION)$$($(CONFIG_SHELL) $(srctree)/scripts/setlocalversion $(srctree))"
@@ -1106,24 +1119,9 @@ scripts: scripts_basic scripts_dtc
 # archprepare is used in arch Makefiles and when processed asm symlink,
 # version.h and scripts_basic is processed / created.
 
-PHONY += prepare archprepare prepare3
+PHONY += prepare archprepare
 
-# prepare3 is used to check if we are building in a separate output directory,
-# and if so do:
-# 1) Check that make has not been executed in the kernel src $(srctree)
-prepare3: include/config/kernel.release
-ifdef building_out_of_srctree
-	@$(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 "  $(srctree) is not clean, please run 'make ARCH=$(ARCH) mrproper'"; \
-		echo >&2 "  in the '$(srctree)' directory.";\
-		/bin/false; \
-	fi;
-endif
-
-archprepare: archheaders archscripts scripts prepare3 outputmakefile \
+archprepare: outputmakefile archheaders archscripts scripts include/config/kernel.release \
 	asm-generic $(version_h) $(autoksyms_h) include/generated/utsrelease.h
 
 prepare0: archprepare
@@ -1248,7 +1246,7 @@ kselftest-merge:
 	$(if $(wildcard $(objtree)/.config),, $(error No .config exists, config your kernel first!))
 	$(Q)find $(srctree)/tools/testing/selftests -name config | \
 		xargs $(srctree)/scripts/kconfig/merge_config.sh -m $(objtree)/.config
-	+$(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig
+	$(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig
 
 # ---------------------------------------------------------------------------
 # Devicetree files
@@ -1259,11 +1257,11 @@ endif
 
 ifneq ($(dtstree),)
 
-%.dtb: prepare3 scripts_dtc
+%.dtb: include/config/kernel.release scripts_dtc
 	$(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@
 
 PHONY += dtbs dtbs_install dt_binding_check
-dtbs dtbs_check: prepare3 scripts_dtc
+dtbs dtbs_check: include/config/kernel.release scripts_dtc
 	$(Q)$(MAKE) $(build)=$(dtstree)
 
 dtbs_check: export CHECK_DTBS=1
@@ -1302,17 +1300,16 @@ all: modules
 
 PHONY += modules
 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.order: $(vmlinux-dirs)
-	$(Q)$(AWK) '!x[$$0]++' $(addsuffix /$@, $(vmlinux-dirs)) > $@
+modules.order: descend
+	$(Q)$(AWK) '!x[$$0]++' $(addsuffix /$@, $(build-dirs)) > $@
 
-modbuiltin-dirs := $(addprefix _modbuiltin_, $(vmlinux-dirs))
+modbuiltin-dirs := $(addprefix _modbuiltin_, $(build-dirs))
 
 modules.builtin: $(modbuiltin-dirs)
-	$(Q)$(AWK) '!x[$$0]++' $(addsuffix /$@, $(vmlinux-dirs)) > $@
+	$(Q)$(AWK) '!x[$$0]++' $(addsuffix /$@, $(build-dirs)) > $@
 
 PHONY += $(modbuiltin-dirs)
 # tristate.conf is not included from this Makefile. Add it as a prerequisite
@@ -1385,12 +1382,14 @@ CLEAN_FILES += modules.builtin.modinfo
 
 # Directories & files removed with 'make mrproper'
 MRPROPER_DIRS  += include/config include/generated          \
-		  arch/$(SRCARCH)/include/generated .tmp_objdiff
+		  arch/$(SRCARCH)/include/generated .tmp_objdiff \
+		  debian/ snap/ tar-install/
 MRPROPER_FILES += .config .config.old .version \
 		  Module.symvers \
 		  signing_key.pem signing_key.priv signing_key.x509	\
 		  x509.genkey extra_certificates signing_key.x509.keyid	\
-		  signing_key.x509.signer vmlinux-gdb.py
+		  signing_key.x509.signer vmlinux-gdb.py \
+		  *.spec
 
 # Directories & files removed with 'make distclean'
 DISTCLEAN_DIRS  +=
@@ -1400,11 +1399,8 @@ DISTCLEAN_FILES += tags TAGS cscope* GPATH GTAGS GRTAGS GSYMS
 #
 clean: rm-dirs  := $(CLEAN_DIRS)
 clean: rm-files := $(CLEAN_FILES)
-clean-dirs      := $(addprefix _clean_, . $(vmlinux-alldirs))
 
-PHONY += $(clean-dirs) clean archclean vmlinuxclean
-$(clean-dirs):
-	$(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
+PHONY += archclean vmlinuxclean
 
 vmlinuxclean:
 	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/link-vmlinux.sh clean
@@ -1445,13 +1441,11 @@ distclean: mrproper
 
 # Packaging of the kernel to various formats
 # ---------------------------------------------------------------------------
-package-dir	:= scripts/package
 
 %src-pkg: FORCE
-	$(Q)$(MAKE) $(build)=$(package-dir) $@
+	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.package $@
 %pkg: include/config/kernel.release FORCE
-	$(Q)$(MAKE) $(build)=$(package-dir) $@
-
+	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.package $@
 
 # Brief documentation of the typical targets used
 # ---------------------------------------------------------------------------
@@ -1525,7 +1519,7 @@ help:
 	@echo '  or  "cd tools; make help"'
 	@echo  ''
 	@echo  'Kernel packaging:'
-	@$(MAKE) $(build)=$(package-dir) help
+	@$(MAKE) -f $(srctree)/scripts/Makefile.package help
 	@echo  ''
 	@echo  'Documentation targets:'
 	@$(MAKE) -f $(srctree)/Documentation/Makefile dochelp
@@ -1550,7 +1544,7 @@ help:
 	@echo  '  make C=1   [targets] Check re-compiled c source with $$CHECK (sparse by default)'
 	@echo  '  make C=2   [targets] Force check of all c source with $$CHECK'
 	@echo  '  make RECORDMCOUNT_WARN=1 [targets] Warn about ignored mcount sections'
-	@echo  '  make W=n   [targets] Enable extra gcc checks, n=1,2,3 where'
+	@echo  '  make W=n   [targets] Enable extra build checks, n=1,2,3 where'
 	@echo  '		1: warnings which may be relevant and do not occur too often'
 	@echo  '		2: warnings which occur quite often but may still be relevant'
 	@echo  '		3: more obscure warnings, can most likely be ignored'
@@ -1579,7 +1573,7 @@ $(help-board-dirs): help-%:
 DOC_TARGETS := xmldocs latexdocs pdfdocs htmldocs epubdocs cleandocs \
 	       linkcheckdocs dochelp refcheckdocs
 PHONY += $(DOC_TARGETS)
-$(DOC_TARGETS): scripts_basic FORCE
+$(DOC_TARGETS):
 	$(Q)$(MAKE) $(build)=Documentation $@
 
 # Misc
@@ -1624,13 +1618,9 @@ $(objtree)/Module.symvers:
 	echo "           is missing; modules will have no dependencies and modversions."; \
 	echo )
 
-module-dirs := $(addprefix _module_,$(KBUILD_EXTMOD))
-PHONY += $(module-dirs) modules
-$(module-dirs): prepare $(objtree)/Module.symvers
-	$(Q)$(MAKE) $(build)=$(patsubst _module_%,%,$@) need-modorder=1
-
-modules: $(module-dirs)
-	@$(kecho) '  Building modules, stage 2.';
+build-dirs := $(KBUILD_EXTMOD)
+PHONY += modules
+modules: descend $(objtree)/Module.symvers
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
 
 PHONY += modules_install
@@ -1646,14 +1636,13 @@ PHONY += _emodinst_post
 _emodinst_post: _emodinst_
 	$(call cmd,depmod)
 
-clean-dirs := $(addprefix _clean_,$(KBUILD_EXTMOD))
-
-PHONY += $(clean-dirs) clean
-$(clean-dirs):
-	$(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
-
+clean-dirs := $(KBUILD_EXTMOD)
 clean: rm-files := $(KBUILD_EXTMOD)/Module.symvers
 
+PHONY += /
+/:
+	@echo >&2 '"$(MAKE) /" is no longer supported. Please use "$(MAKE) ./" instead.'
+
 PHONY += help
 help:
 	@echo  '  Building external modules.'
@@ -1667,6 +1656,21 @@ help:
 PHONY += prepare
 endif # KBUILD_EXTMOD
 
+# Handle descending into subdirectories listed in $(build-dirs)
+# Preset locale variables to speed up the build process. Limit locale
+# tweaks to this spot to avoid wrong language settings when running
+# make menuconfig etc.
+# Error messages still appears in the original language
+PHONY += descend $(build-dirs)
+descend: $(build-dirs)
+$(build-dirs): prepare
+	$(Q)$(MAKE) $(build)=$@ single-build=$(single-build) need-builtin=1 need-modorder=1
+
+clean-dirs := $(addprefix _clean_, $(clean-dirs))
+PHONY += $(clean-dirs) clean
+$(clean-dirs):
+	$(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
+
 clean: $(clean-dirs)
 	$(call cmd,rmdirs)
 	$(call cmd,rmfiles)
@@ -1688,7 +1692,7 @@ clean: $(clean-dirs)
 # Generate tags for editors
 # ---------------------------------------------------------------------------
 quiet_cmd_tags = GEN     $@
-      cmd_tags = $(CONFIG_SHELL) $(srctree)/scripts/tags.sh $@
+      cmd_tags = $(BASH) $(srctree)/scripts/tags.sh $@
 
 tags TAGS cscope gtags: FORCE
 	$(call cmd,tags)
@@ -1709,7 +1713,7 @@ versioncheck:
 		| xargs $(PERL) -w $(srctree)/scripts/checkversion.pl
 
 coccicheck:
-	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/$@
+	$(Q)$(BASH) $(srctree)/scripts/$@
 
 namespacecheck:
 	$(PERL) $(srctree)/scripts/namespace.pl
@@ -1757,45 +1761,47 @@ tools/%: FORCE
 
 # Single targets
 # ---------------------------------------------------------------------------
-# Single targets are compatible with:
-# - build with mixed source and output
-# - build with separate output dir 'make O=...'
-# - external modules
+# To build individual files in subdirectories, you can do like this:
+#
+#   make foo/bar/baz.s
 #
-#  target-dir => where to store outputfile
-#  build-dir  => directory in kernel source tree to use
-
-build-target = $(if $(KBUILD_EXTMOD), $(KBUILD_EXTMOD)/)$@
-build-dir = $(patsubst %/,%,$(dir $(build-target)))
-
-%.i: prepare FORCE
-	$(Q)$(MAKE) $(build)=$(build-dir) $(build-target)
-%.ll: prepare FORCE
-	$(Q)$(MAKE) $(build)=$(build-dir) $(build-target)
-%.lst: prepare FORCE
-	$(Q)$(MAKE) $(build)=$(build-dir) $(build-target)
-%.o: prepare FORCE
-	$(Q)$(MAKE) $(build)=$(build-dir) $(build-target)
-%.s: prepare FORCE
-	$(Q)$(MAKE) $(build)=$(build-dir) $(build-target)
-%.symtypes: prepare FORCE
-	$(Q)$(MAKE) $(build)=$(build-dir) $(build-target)
+# The supported suffixes for single-target are listed in 'single-targets'
+#
+# To build only under specific subdirectories, you can do like this:
+#
+#   make foo/bar/baz/
+
+ifdef single-build
+
+single-all := $(filter $(single-targets), $(MAKECMDGOALS))
+
+# .ko is special because modpost is needed
+single-ko := $(sort $(filter %.ko, $(single-all)))
+single-no-ko := $(sort $(patsubst %.ko,%.mod, $(single-all)))
+
+$(single-ko): single_modpost
+	@:
+$(single-no-ko): descend
+	@:
+
 ifeq ($(KBUILD_EXTMOD),)
-# For the single build of an in-tree module, use a temporary file to avoid
+# For the single build of in-tree modules, use a temporary file to avoid
 # the situation of modules_install installing an invalid modules.order.
-%.ko: MODORDER := .modules.tmp
+MODORDER := .modules.tmp
 endif
-%.ko: prepare FORCE
-	$(Q)$(MAKE) $(build)=$(build-dir) $(build-target:.ko=.mod)
-	$(Q)echo $(build-target) > $(MODORDER)
+
+PHONY += single_modpost
+single_modpost: $(single-no-ko)
+	$(Q){ $(foreach m, $(single-ko), echo $(extmod-prefix)$m;) } > $(MODORDER)
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
 
-# Modules
-PHONY += /
-/: ./
+KBUILD_MODULES := 1
 
-%/: prepare FORCE
-	$(Q)$(MAKE) KBUILD_MODULES=1 $(build)=$(build-dir) need-modorder=1
+export KBUILD_SINGLE_TARGETS := $(addprefix $(extmod-prefix), $(single-no-ko))
+
+single-build = $(if $(filter-out $@/, $(single-no-ko)),1)
+
+endif
 
 # FIXME Should go into a make.lib or something
 # ===========================================================================
@@ -1816,9 +1822,9 @@ existing-targets := $(wildcard $(sort $(targets)))
 
 -include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
 
-endif   # ifeq ($(config-targets),1)
-endif   # ifeq ($(mixed-targets),1)
-endif   # need-sub-make
+endif # config-targets
+endif # mixed-build
+endif # need-sub-make
 
 PHONY += FORCE
 FORCE: