Merge tag 'kbuild-v5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull more Kbuild updates from Masahiro Yamada:

 - Convert sh and sparc to use generic shell scripts to generate the
   syscall headers

 - refactor .gitignore files

 - Update kernel/config_data.gz only when the content of the .config
   is really changed, which avoids the unneeded re-link of vmlinux

 - move "remove stale files" workarounds to scripts/remove-stale-files

 - suppress unused-but-set-variable warnings by default for Clang
   as well

 - fix locale setting LANG=C to LC_ALL=C

 - improve 'make distclean'

 - always keep intermediate objects from scripts/link-vmlinux.sh

 - move IF_ENABLED out of <linux/kconfig.h> to make it self-contained

 - misc cleanups

* tag 'kbuild-v5.13-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (25 commits)
  linux/kconfig.h: replace IF_ENABLED() with PTR_IF() in <linux/kernel.h>
  kbuild: Don't remove link-vmlinux temporary files on exit/signal
  kbuild: remove the unneeded comments for external module builds
  kbuild: make distclean remove tag files in sub-directories
  kbuild: make distclean work against $(objtree) instead of $(srctree)
  kbuild: refactor modname-multi by using suffix-search
  kbuild: refactor fdtoverlay rule
  kbuild: parameterize the .o part of suffix-search
  arch: use cross_compiling to check whether it is a cross build or not
  kbuild: remove ARCH=sh64 support from top Makefile
  .gitignore: prefix local generated files with a slash
  kbuild: replace LANG=C with LC_ALL=C
  Makefile: Move -Wno-unused-but-set-variable out of GCC only block
  kbuild: add a script to remove stale generated files
  kbuild: update config_data.gz only when the content of .config is changed
  .gitignore: ignore only top-level modules.builtin
  .gitignore: move tags and TAGS close to other tag files
  kernel/.gitgnore: remove stale timeconst.h and hz.bc
  usr/include: refactor .gitignore
  genksyms: fix stale comment
  ...

15 files changed, 85 insertions, 65 deletions

diff --git a/scripts/.gitignore b/scripts/.gitignore
index a6c11316c969..e83c620ef52c 100644
--- a/scripts/.gitignore
+++ b/scripts/.gitignore
@@ -1,11 +1,11 @@
 # SPDX-License-Identifier: GPL-2.0-only
-bin2c
-kallsyms
-unifdef
-recordmcount
-sorttable
-asn1_compiler
-extract-cert
-sign-file
-insert-sys-cert
+/asn1_compiler
+/bin2c
+/extract-cert
+/insert-sys-cert
+/kallsyms
 /module.lds
+/recordmcount
+/sign-file
+/sorttable
+/unifdef
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 5e39b0517186..949f723efe53 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -354,7 +354,7 @@ $(obj)/%.o: $(src)/%.S $(objtool_dep) FORCE
 
 targets += $(filter-out $(subdir-builtin), $(real-obj-y))
 targets += $(filter-out $(subdir-modorder), $(real-obj-m))
-targets += $(lib-y) $(always-y) $(MAKECMDGOALS)
+targets += $(real-dtb-y) $(lib-y) $(always-y) $(MAKECMDGOALS)
 
 # Linker scripts preprocessor (.lds.S -> .lds)
 # ---------------------------------------------------------------------------
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 64daf37e874b..10950559b223 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -44,19 +44,22 @@ else
 obj-y		:= $(filter-out %/, $(obj-y))
 endif
 
-# Expand $(foo-objs) $(foo-y) by calling $(call suffix-search,foo.o,-objs -y)
-suffix-search = $(strip $(foreach s, $2, $($(1:.o=$s))))
+# Expand $(foo-objs) $(foo-y) etc. by replacing their individuals
+suffix-search = $(strip $(foreach s, $3, $($(1:%$(strip $2)=%$s))))
+# List composite targets that are constructed by combining other targets
+multi-search = $(sort $(foreach m, $1, $(if $(call suffix-search, $m, $2, $3 -), $m)))
+# List primitive targets that are compiled from source files
+real-search = $(foreach m, $1, $(if $(call suffix-search, $m, $2, $3 -), $(call suffix-search, $m, $2, $3), $m))
+
 # If $(foo-objs), $(foo-y), $(foo-m), or $(foo-) exists, foo.o is a composite object
-multi-search = $(sort $(foreach m, $1, $(if $(call suffix-search, $m, $2 -), $m)))
-multi-obj-y := $(call multi-search,$(obj-y),-objs -y)
-multi-obj-m := $(call multi-search,$(obj-m),-objs -y -m)
+multi-obj-y := $(call multi-search, $(obj-y), .o, -objs -y)
+multi-obj-m := $(call multi-search, $(obj-m), .o, -objs -y -m)
 multi-obj-ym := $(multi-obj-y) $(multi-obj-m)
 
 # Replace multi-part objects by their individual parts,
 # including built-in.a from subdirectories
-real-search = $(foreach m, $1, $(if $(call suffix-search, $m, $2 -), $(call suffix-search, $m, $2), $m))
-real-obj-y := $(call real-search, $(obj-y),-objs -y)
-real-obj-m := $(call real-search, $(obj-m),-objs -y -m)
+real-obj-y := $(call real-search, $(obj-y), .o, -objs -y)
+real-obj-m := $(call real-search, $(obj-m), .o, -objs -y -m)
 
 always-y += $(always-m)
 
@@ -75,24 +78,18 @@ always-y += $(userprogs-always-y) $(userprogs-always-m)
 # If CONFIG_OF_ALL_DTBS is enabled, all DT blobs are built
 dtb-$(CONFIG_OF_ALL_DTBS)       += $(dtb-)
 
-# List all dtbs to be generated by fdtoverlay
-overlay-y := $(foreach m,$(dtb-y), $(if $(strip $($(m:.dtb=-dtbs))),$(m),))
-
-# Generate symbols for the base files so overlays can be applied to them.
-$(foreach m,$(overlay-y), $(eval DTC_FLAGS_$(basename $(firstword $($(m:.dtb=-dtbs)))) += -@))
-
-# Add base dtb and overlay dtbo
-dtb-y += $(foreach m,$(overlay-y), $($(m:.dtb=-dtbs)))
+# Composite DTB (i.e. DTB constructed by overlay)
+multi-dtb-y := $(call multi-search, $(dtb-y), .dtb, -dtbs)
+# Primitive DTB compiled from *.dts
+real-dtb-y := $(call real-search, $(dtb-y), .dtb, -dtbs)
+# Base DTB that overlay is applied onto (each first word of $(*-dtbs) expansion)
+base-dtb-y := $(foreach m, $(multi-dtb-y), $(firstword $(call suffix-search, $m, .dtb, -dtbs)))
 
 always-y			+= $(dtb-y)
 
 ifneq ($(CHECK_DTBS),)
-# Don't run schema checks for dtbs created by fdtoverlay as they don't
-# have corresponding dts files.
-dt-yaml-y := $(filter-out $(overlay-y),$(dtb-y))
-
-always-y += $(patsubst %.dtb,%.dt.yaml, $(dt-yaml-y))
-always-y += $(patsubst %.dtbo,%.dt.yaml, $(dt-yaml-y))
+always-y += $(patsubst %.dtb,%.dt.yaml, $(real-dtb-y))
+always-y += $(patsubst %.dtbo,%.dt.yaml, $(real-dtb-y))
 endif
 
 # Add subdir path
@@ -105,12 +102,14 @@ lib-y		:= $(addprefix $(obj)/,$(lib-y))
 real-obj-y	:= $(addprefix $(obj)/,$(real-obj-y))
 real-obj-m	:= $(addprefix $(obj)/,$(real-obj-m))
 multi-obj-m	:= $(addprefix $(obj)/, $(multi-obj-m))
+multi-dtb-y	:= $(addprefix $(obj)/, $(multi-dtb-y))
+real-dtb-y	:= $(addprefix $(obj)/, $(real-dtb-y))
 subdir-ym	:= $(addprefix $(obj)/,$(subdir-ym))
 
 # Finds the multi-part object the current object will be linked into.
 # If the object belongs to two or more multi-part objects, list them all.
 modname-multi = $(sort $(foreach m,$(multi-obj-ym),\
-		$(if $(filter $*.o, $($(m:.o=-objs)) $($(m:.o=-y)) $($(m:.o=-m))),$(m:.o=))))
+		$(if $(filter $*.o, $(call suffix-search, $m, .o, -objs -y -m)),$(m:.o=))))
 
 __modname = $(if $(modname-multi),$(modname-multi),$(basetarget))
 
@@ -252,6 +251,9 @@ quiet_cmd_copy = COPY    $@
 
 # Shipped files
 # ===========================================================================
+# 'cp' preserves permissions. If you use it to copy a file in read-only srctree,
+# the copy would be read-only as well, leading to an error when executing the
+# rule next time. Use 'cat' instead in order to generate a writable file.
 
 quiet_cmd_shipped = SHIPPED $@
 cmd_shipped = cat $< > $@
@@ -319,6 +321,9 @@ endif
 
 DTC_FLAGS += $(DTC_FLAGS_$(basetarget))
 
+# Set -@ if the target is a base DTB that overlay is applied onto
+DTC_FLAGS += $(if $(filter $(patsubst $(obj)/%,%,$@), $(base-dtb-y)), -@)
+
 # Generate an assembly file to wrap the output of the device tree compiler
 quiet_cmd_dt_S_dtb= DTB     $@
 cmd_dt_S_dtb=						\
@@ -350,14 +355,12 @@ $(obj)/%.dtb: $(src)/%.dts $(DTC) FORCE
 $(obj)/%.dtbo: $(src)/%.dts $(DTC) FORCE
 	$(call if_changed_dep,dtc)
 
-overlay-y := $(addprefix $(obj)/, $(overlay-y))
-
 quiet_cmd_fdtoverlay = DTOVL   $@
       cmd_fdtoverlay = $(objtree)/scripts/dtc/fdtoverlay -o $@ -i $(real-prereqs)
 
-$(overlay-y): FORCE
+$(multi-dtb-y): FORCE
 	$(call if_changed,fdtoverlay)
-$(call multi_depend, $(overlay-y), .dtb, -dtbs)
+$(call multi_depend, $(multi-dtb-y), .dtb, -dtbs)
 
 DT_CHECKER ?= dt-validate
 DT_CHECKER_FLAGS ?= $(if $(DT_SCHEMA_FILES),,-m)
diff --git a/scripts/basic/.gitignore b/scripts/basic/.gitignore
index 98ae1f509592..961c91c8a884 100644
--- a/scripts/basic/.gitignore
+++ b/scripts/basic/.gitignore
@@ -1,2 +1,2 @@
 # SPDX-License-Identifier: GPL-2.0-only
-fixdep
+/fixdep
diff --git a/scripts/dtc/.gitignore b/scripts/dtc/.gitignore
index 8a8b62bf3d3c..e0b5c1d2464a 100644
--- a/scripts/dtc/.gitignore
+++ b/scripts/dtc/.gitignore
@@ -1,3 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0-only
-dtc
-fdtoverlay
+/dtc
+/fdtoverlay
diff --git a/scripts/gcc-plugins/.gitignore b/scripts/gcc-plugins/.gitignore
index b04e0f0f033e..5cc385b9eb97 100644
--- a/scripts/gcc-plugins/.gitignore
+++ b/scripts/gcc-plugins/.gitignore
@@ -1,2 +1,2 @@
 # SPDX-License-Identifier: GPL-2.0-only
-randomize_layout_seed.h
+/randomize_layout_seed.h
diff --git a/scripts/genksyms/.gitignore b/scripts/genksyms/.gitignore
index 999af710f83d..0b275abf9405 100644
--- a/scripts/genksyms/.gitignore
+++ b/scripts/genksyms/.gitignore
@@ -1,2 +1,2 @@
 # SPDX-License-Identifier: GPL-2.0-only
-genksyms
+/genksyms
diff --git a/scripts/genksyms/Makefile b/scripts/genksyms/Makefile
index ce4f99935de5..d6a422a63b6a 100644
--- a/scripts/genksyms/Makefile
+++ b/scripts/genksyms/Makefile
@@ -22,7 +22,7 @@ $(obj)/pars%.tab.c $(obj)/pars%.tab.h: $(src)/pars%.y FORCE
 
 endif
 
-# -I needed for generated C source (shipped source)
+# -I needed for generated C source to include headers in source tree
 HOSTCFLAGS_parse.tab.o := -I $(srctree)/$(src)
 HOSTCFLAGS_lex.lex.o := -I $(srctree)/$(src)
 
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 7d112681f332..f4de4c97015b 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -320,20 +320,6 @@ cleanup()
 	rm -f .vmlinux.d
 }
 
-on_exit()
-{
-	if [ $? -ne 0 ]; then
-		cleanup
-	fi
-}
-trap on_exit EXIT
-
-on_signals()
-{
-	exit 1
-}
-trap on_signals HUP INT QUIT TERM
-
 # Use "make V=1" to debug this script
 case "${KBUILD_VERBOSE}" in
 *1*)
diff --git a/scripts/mod/.gitignore b/scripts/mod/.gitignore
index 07e4a39f90a6..0465ec33c9bf 100644
--- a/scripts/mod/.gitignore
+++ b/scripts/mod/.gitignore
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
-elfconfig.h
-mk_elfconfig
-modpost
-devicetable-offsets.h
+/devicetable-offsets.h
+/elfconfig.h
+/mk_elfconfig
+/modpost
diff --git a/scripts/nsdeps b/scripts/nsdeps
index e8ce2a4d704a..04c4b96e95ec 100644
--- a/scripts/nsdeps
+++ b/scripts/nsdeps
@@ -44,7 +44,7 @@ generate_deps() {
 		for source_file in $mod_source_files; do
 			sed '/MODULE_IMPORT_NS/Q' $source_file > ${source_file}.tmp
 			offset=$(wc -l ${source_file}.tmp | awk '{print $1;}')
-			cat $source_file | grep MODULE_IMPORT_NS | LANG=C sort -u >> ${source_file}.tmp
+			cat $source_file | grep MODULE_IMPORT_NS | LC_ALL=C sort -u >> ${source_file}.tmp
 			tail -n +$((offset +1)) ${source_file} | grep -v MODULE_IMPORT_NS >> ${source_file}.tmp
 			if ! diff -q ${source_file} ${source_file}.tmp; then
 				mv ${source_file}.tmp ${source_file}
diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
index 5053b78da19e..c17e48020ec3 100755
--- a/scripts/recordmcount.pl
+++ b/scripts/recordmcount.pl
@@ -497,7 +497,7 @@ sub update_funcs
 #
 # Step 2: find the sections and mcount call sites
 #
-open(IN, "LANG=C $objdump -hdr $inputfile|") || die "error running $objdump";
+open(IN, "LC_ALL=C $objdump -hdr $inputfile|") || die "error running $objdump";
 
 my $text;
 
diff --git a/scripts/remove-stale-files b/scripts/remove-stale-files
new file mode 100755
index 000000000000..c3eb81c3f7de
--- /dev/null
+++ b/scripts/remove-stale-files
@@ -0,0 +1,31 @@
+#!/bin/sh
+
+set -e
+
+# When you move, remove or rename generated files, you probably also update
+# .gitignore and cleaning rules in the Makefile. This is the right thing
+# to do. However, people usually do 'git pull', 'git bisect', etc. without
+# running 'make clean'. Then, the stale generated files are left over, often
+# causing build issues.
+#
+# Also, 'git status' shows such stale build artifacts as untracked files.
+# What is worse, some people send a wrong patch to get them back to .gitignore
+# without checking the commit history.
+#
+# So, when you (re)move generated files, please move the cleaning rules from
+# the Makefile to this script. This is run before Kbuild starts building
+# anything, so people will not be annoyed by such garbage files.
+#
+# This script is not intended to grow endlessly. Rather, it is a temporary scrap
+# yard. Stale files stay in this file for a while (for some release cycles?),
+# then will be really dead and removed from the code base entirely.
+
+# These were previously generated source files. When you are building the kernel
+# with O=, make sure to remove the stale files in the output tree. Otherwise,
+# the build system wrongly compiles the stale ones.
+if [ -n "${building_out_of_srctree}" ]; then
+	for f in fdt_rw.c fdt_ro.c fdt_wip.c fdt.c
+	do
+		rm -f arch/arm/boot/compressed/${f}
+	done
+fi
diff --git a/scripts/setlocalversion b/scripts/setlocalversion
index bb709eda96cd..db941f6d9591 100755
--- a/scripts/setlocalversion
+++ b/scripts/setlocalversion
@@ -126,7 +126,7 @@ scm_version()
 	fi
 
 	# Check for svn and a svn repo.
-	if rev=$(LANG= LC_ALL= LC_MESSAGES=C svn info 2>/dev/null | grep '^Last Changed Rev'); then
+	if rev=$(LC_ALL=C svn info 2>/dev/null | grep '^Last Changed Rev'); then
 		rev=$(echo $rev | awk '{print $NF}')
 		printf -- '-svn%s' "$rev"
 
diff --git a/scripts/tags.sh b/scripts/tags.sh
index fd96734deff1..db8ba411860a 100755
--- a/scripts/tags.sh
+++ b/scripts/tags.sh
@@ -326,5 +326,5 @@ esac
 
 # Remove structure forward declarations.
 if [ -n "$remove_structs" ]; then
-    LANG=C sed -i -e '/^\([a-zA-Z_][a-zA-Z0-9_]*\)\t.*\t\/\^struct \1;.*\$\/;"\tx$/d' $1
+    LC_ALL=C sed -i -e '/^\([a-zA-Z_][a-zA-Z0-9_]*\)\t.*\t\/\^struct \1;.*\$\/;"\tx$/d' $1
 fi