Merge tag 'kbuild-fixes-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild fixes from Masahiro Yamada:

- fix linker script regression caused by dead code elimination support

- fix typos and outdated comments

- specify kselftest-clean as a PHONY target

- fix "make dtbs_install" when $(srctree) includes shell special
characters like '~'

- Move -fshort-wchar to the global option list because defining it
partially emits warnings

* tag 'kbuild-fixes-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: update comments of Makefile.asm-generic
kbuild: Do not use hyphen in exported variable name
Makefile: add kselftest-clean to PHONY target list
Kbuild: use -fshort-wchar globally
fixdep: trivial: typo fix and correction
kbuild: trivial cleanups on the comments
kbuild: linker script do not match C names unless LD_DEAD_CODE_DATA_ELIMINATION is configured

Makefile

···
 KBUILD_CPPFLAGS := -D__KERNEL__
 
 KBUILD_CFLAGS   := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
-		   -fno-strict-aliasing -fno-common \
+		   -fno-strict-aliasing -fno-common -fshort-wchar \
 		   -Werror-implicit-function-declaration \
 		   -Wno-format-security \
 		   -std=gnu89 $(call cc-option,-fno-PIE)
···
 # ===========================================================================
 # Rules shared between *config targets and build targets
 
-# Basic helpers built in scripts/
+# Basic helpers built in scripts/basic/
 PHONY += scripts_basic
 scripts_basic:
 	$(Q)$(MAKE) $(build)=scripts/basic
···
                 endif
         endif
 endif
-# install and module_install need also be processed one by one
+# install and modules_install need also be processed one by one
 ifneq ($(filter install,$(MAKECMDGOALS)),)
         ifneq ($(filter modules_install,$(MAKECMDGOALS)),)
 	        mixed-targets := 1
···
 export KBUILD_VMLINUX_LIBS := $(libs-y1)
 export KBUILD_LDS          := arch/$(SRCARCH)/kernel/vmlinux.lds
 export LDFLAGS_vmlinux
-# used by scripts/pacmage/Makefile
+# used by scripts/package/Makefile
 export KBUILD_ALLDIRS := $(sort $(filter-out arch/%,$(vmlinux-alldirs)) arch Documentation include samples scripts tools)
 
 vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_INIT) $(KBUILD_VMLINUX_MAIN) $(KBUILD_VMLINUX_LIBS)
···
 ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
 
 # Final link of vmlinux with optional arch pass after final link
-    cmd_link-vmlinux =                                                 \
-	$(CONFIG_SHELL) $< $(LD) $(LDFLAGS) $(LDFLAGS_vmlinux) ;       \
+cmd_link-vmlinux =                                                 \
+	$(CONFIG_SHELL) $< $(LD) $(LDFLAGS) $(LDFLAGS_vmlinux) ;    \
 	$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
 
 vmlinux: scripts/link-vmlinux.sh vmlinux_prereq $(vmlinux-deps) FORCE
···
 kselftest:
 	$(Q)$(MAKE) -C tools/testing/selftests run_tests
 
+PHONY += kselftest-clean
 kselftest-clean:
 	$(Q)$(MAKE) -C tools/testing/selftests clean
 

drivers/xen/Makefile

···
 nostackp := $(call cc-option, -fno-stack-protector)
 CFLAGS_features.o			:= $(nostackp)
 
-CFLAGS_efi.o				+= -fshort-wchar
-LDFLAGS					+= $(call ld-option, --no-wchar-size-warning)
-
 dom0-$(CONFIG_ARM64) += arm-device.o
 dom0-$(CONFIG_PCI) += pci.o
 dom0-$(CONFIG_USB_SUPPORT) += dbgp.o

include/asm-generic/vmlinux.lds.h

···
 #define ALIGN_FUNCTION()  . = ALIGN(8)
 
 /*
+ * LD_DEAD_CODE_DATA_ELIMINATION option enables -fdata-sections, which
+ * generates .data.identifier sections, which need to be pulled in with
+ * .data. We don't want to pull in .data..other sections, which Linux
+ * has defined. Same for text and bss.
+ */
+#ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
+#define TEXT_MAIN .text .text.[0-9a-zA-Z_]*
+#define DATA_MAIN .data .data.[0-9a-zA-Z_]*
+#define BSS_MAIN .bss .bss.[0-9a-zA-Z_]*
+#else
+#define TEXT_MAIN .text
+#define DATA_MAIN .data
+#define BSS_MAIN .bss
+#endif
+
+/*
  * Align to a 32 byte boundary equal to the
  * alignment gcc 4.5 uses for a struct
  */
···
 
 /*
  * .data section
- * LD_DEAD_CODE_DATA_ELIMINATION option enables -fdata-sections generates
- * .data.identifier which needs to be pulled in with .data, but don't want to
- * pull in .data..stuff which has its own requirements. Same for bss.
  */
 #define DATA_DATA							\
-	*(.data .data.[0-9a-zA-Z_]*)					\
+	*(DATA_MAIN)							\
 	*(.ref.data)							\
 	*(.data..shared_aligned) /* percpu related */			\
 	MEM_KEEP(init.data)						\
···
 		VMLINUX_SYMBOL(__security_initcall_end) = .;		\
 	}
 
-/* .text section. Map to function alignment to avoid address changes
+/*
+ * .text section. Map to function alignment to avoid address changes
  * during second ld run in second ld pass when generating System.map
- * LD_DEAD_CODE_DATA_ELIMINATION option enables -ffunction-sections generates
- * .text.identifier which needs to be pulled in with .text , but some
- * architectures define .text.foo which is not intended to be pulled in here.
- * Those enabling LD_DEAD_CODE_DATA_ELIMINATION must ensure they don't have
- * conflicting section names, and must pull in .text.[0-9a-zA-Z_]* */
+ *
+ * TEXT_MAIN here will match .text.fixup and .text.unlikely if dead
+ * code elimination is enabled, so these sections should be converted
+ * to use ".." first.
+ */
 #define TEXT_TEXT							\
 		ALIGN_FUNCTION();					\
-		*(.text.hot .text .text.fixup .text.unlikely)		\
+		*(.text.hot TEXT_MAIN .text.fixup .text.unlikely)	\
 		*(.ref.text)						\
 	MEM_KEEP(init.text)						\
 	MEM_KEEP(exit.text)						\
···
 		BSS_FIRST_SECTIONS					\
 		*(.bss..page_aligned)					\
 		*(.dynbss)						\
-		*(.bss .bss.[0-9a-zA-Z_]*)				\
+		*(BSS_MAIN)						\
 		*(COMMON)						\
 	}
 

scripts/Kbuild.include

···
 
 # try-run
 # Usage: option = $(call try-run, $(CC)...-o "$$TMP",option-ok,otherwise)
-# Exit code chooses option. "$$TMP" is can be used as temporary file and
-# is automatically cleaned up.
+# Exit code chooses option. "$$TMP" serves as a temporary file and is
+# automatically cleaned up.
 try-run = $(shell set -e;		\
 	TMP="$(TMPOUT).$$$$.tmp";	\
 	TMPO="$(TMPOUT).$$$$.o";	\
···
 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)),                       \
 	@set -e;                                                             \
 	$(echo-cmd) $(cmd_$(1));                                             \
···
 	$(rule_$(1)), @:)
 
 ###
-# why - tell why a a target got build
+# why - tell why a target got built
 #       enabled by make V=2
 #       Output (listed in the order they are checked):
 #          (1) - due to target is PHONY

scripts/Makefile.asm-generic

···
 # include/asm-generic contains a lot of files that are used
 # verbatim by several architectures.
 #
-# This Makefile reads the file arch/$(SRCARCH)/include/asm/Kbuild
+# This Makefile reads the file arch/$(SRCARCH)/include/$(src)/Kbuild
 # and for each file listed in this file with generic-y creates
-# a small wrapper file in $(obj) (arch/$(SRCARCH)/include/generated/asm)
+# a small wrapper file in $(obj) (arch/$(SRCARCH)/include/generated/$(src))
 
 kbuild-file := $(srctree)/arch/$(SRCARCH)/include/$(src)/Kbuild
 -include $(kbuild-file)

scripts/Makefile.build

···
 endif
 # Due to recursion, we must skip empty.o.
 # The empty.o file is created in the make process in order to determine
-#  the target endianness and word size. It is made before all other C
-#  files, including recordmcount.
+# the target endianness and word size. It is made before all other C
+# files, including recordmcount.
 sub_cmd_record_mcount =					\
 	if [ $(@) != "scripts/mod/empty.o" ]; then	\
 		$(objtree)/scripts/recordmcount $(RECORDMCOUNT_FLAGS) "$(@)";	\
···
 	"$(LD)" "$(NM)" "$(RM)" "$(MV)" \
 	"$(if $(part-of-module),1,0)" "$(@)";
 recordmcount_source := $(srctree)/scripts/recordmcount.pl
-endif
+endif # BUILD_C_RECORDMCOUNT
 cmd_record_mcount =						\
 	if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" =	\
 	     "$(CC_FLAGS_FTRACE)" ]; then			\
 		$(sub_cmd_record_mcount)			\
 	fi;
-endif
+endif # CONFIG_FTRACE_MCOUNT_RECORD
 
 ifdef CONFIG_STACK_VALIDATION
 ifneq ($(SKIP_STACK_VALIDATION),1)

scripts/Makefile.dtbinst

···
 PHONY := __dtbs_install
 __dtbs_install:
 
-export dtbinst-root ?= $(obj)
+export dtbinst_root ?= $(obj)
 
 include include/config/auto.conf
 include scripts/Kbuild.include
···
 quiet_cmd_dtb_install =	INSTALL $<
       cmd_dtb_install =	mkdir -p $(2); cp $< $(2)
 
-install-dir = $(patsubst $(dtbinst-root)%,$(INSTALL_DTBS_PATH)%,$(obj))
+install-dir = $(patsubst $(dtbinst_root)%,$(INSTALL_DTBS_PATH)%,$(obj))
 
 $(dtbinst-files): %.dtb: $(obj)/%.dtb
 	$(call cmd,dtb_install,$(install-dir))

scripts/basic/Makefile

···
 ###
-# Makefile.basic lists the most basic programs used during the build process.
+# This Makefile lists the most basic programs used during the build process.
 # The programs listed herein are what are needed to do the basic stuff,
 # such as fix file dependencies.
 # This initial step is needed to avoid files to be recompiled

scripts/basic/fixdep.c

···
  *
  * So we play the same trick that "mkdep" played before. We replace
  * the dependency on autoconf.h by a dependency on every config
- * option which is mentioned in any of the listed prequisites.
+ * option which is mentioned in any of the listed prerequisites.
  *
  * kconfig populates a tree in include/config/ with an empty file
  * for each config symbol and when the configuration is updated
···
  * the config symbols are rebuilt.
  *
  * So if the user changes his CONFIG_HIS_DRIVER option, only the objects
- * which depend on "include/linux/config/his/driver.h" will be rebuilt,
+ * which depend on "include/config/his/driver.h" will be rebuilt,
  * so most likely only his driver ;-)
  *
  * The idea above dates, by the way, back to Michael E Chastain, AFAIK.
···
  * and then basically copies the .<target>.d file to stdout, in the
  * process filtering out the dependency on autoconf.h and adding
  * dependencies on include/config/my/option.h for every
- * CONFIG_MY_OPTION encountered in any of the prequisites.
+ * CONFIG_MY_OPTION encountered in any of the prerequisites.
  *
  * It will also filter out all the dependencies on *.ver. We need
  * to make sure that the generated version checksum are globally up