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
  ...

init/Kconfig

@@ -1234,20 +1234,26 @@ choice
 	default CC_OPTIMIZE_FOR_PERFORMANCE
 
 config CC_OPTIMIZE_FOR_PERFORMANCE
-	bool "Optimize for performance"
+	bool "Optimize for performance (-O2)"
 	help
 	  This is the default optimization level for the kernel, building
 	  with the "-O2" compiler flag for best performance and most
 	  helpful compile-time warnings.
 
-config CC_OPTIMIZE_FOR_SIZE
-	bool "Optimize for size"
+config CC_OPTIMIZE_FOR_PERFORMANCE_O3
+	bool "Optimize more for performance (-O3)"
+	depends on ARC
 	imply CC_DISABLE_WARN_MAYBE_UNINITIALIZED  # avoid false positives
 	help
-	  Enabling this option will pass "-Os" instead of "-O2" to
-	  your compiler resulting in a smaller kernel.
+	  Choosing this option will pass "-O3" to your compiler to optimize
+	  the kernel yet more for performance.
 
-	  If unsure, say N.
+config CC_OPTIMIZE_FOR_SIZE
+	bool "Optimize for size (-Os)"
+	imply CC_DISABLE_WARN_MAYBE_UNINITIALIZED  # avoid false positives
+	help
+	  Choosing this option will pass "-Os" to your compiler resulting
+	  in a smaller kernel.
 
 endchoice
 
@@ -2014,6 +2020,14 @@ config MODVERSIONS
 	  make them incompatible with the kernel you are running.  If
 	  unsure, say N.
 
+config ASM_MODVERSIONS
+	bool
+	default HAVE_ASM_MODVERSIONS && MODVERSIONS
+	help
+	  This enables module versioning for exported symbols also from
+	  assembly. This can be enabled only when the target architecture
+	  supports it.
+
 config MODULE_REL_CRCS
 	bool
 	depends on MODVERSIONS

init/Makefile

@@ -33,5 +33,6 @@ $(obj)/version.o: include/generated/compile.h
 silent_chk_compile.h = :
 include/generated/compile.h: FORCE
 	@$($(quiet)chk_compile.h)
-	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkcompile_h $@ \
-	"$(UTS_MACHINE)" "$(CONFIG_SMP)" "$(CONFIG_PREEMPT)" "$(CC) $(KBUILD_CFLAGS)"
+	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkcompile_h $@	\
+	"$(UTS_MACHINE)" "$(CONFIG_SMP)" "$(CONFIG_PREEMPT)"	\
+	"$(CONFIG_PREEMPT_RT)" "$(CC) $(KBUILD_CFLAGS)"