Merge tag 'kbuild-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Add -s option (strict mode) to merge_config.sh to make it fail when
   any symbol is redefined.

 - Show a warning if a different compiler is used for building external
   modules.

 - Infer --target from ARCH for CC=clang to let you cross-compile the
   kernel without CROSS_COMPILE.

 - Make the integrated assembler default (LLVM_IAS=1) for CC=clang.

 - Add <linux/stdarg.h> to the kernel source instead of borrowing
   <stdarg.h> from the compiler.

 - Add Nick Desaulniers as a Kbuild reviewer.

 - Drop stale cc-option tests.

 - Fix the combination of CONFIG_TRIM_UNUSED_KSYMS and CONFIG_LTO_CLANG
   to handle symbols in inline assembly.

 - Show a warning if 'FORCE' is missing for if_changed rules.

 - Various cleanups

* tag 'kbuild-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (39 commits)
  kbuild: redo fake deps at include/ksym/*.h
  kbuild: clean up objtool_args slightly
  modpost: get the *.mod file path more simply
  checkkconfigsymbols.py: Fix the '--ignore' option
  kbuild: merge vmlinux_link() between ARCH=um and other architectures
  kbuild: do not remove 'linux' link in scripts/link-vmlinux.sh
  kbuild: merge vmlinux_link() between the ordinary link and Clang LTO
  kbuild: remove stale *.symversions
  kbuild: remove unused quiet_cmd_update_lto_symversions
  gen_compile_commands: extract compiler command from a series of commands
  x86: remove cc-option-yn test for -mtune=
  arc: replace cc-option-yn uses with cc-option
  s390: replace cc-option-yn uses with cc-option
  ia64: move core-y in arch/ia64/Makefile to arch/ia64/Kbuild
  sparc: move the install rule to arch/sparc/Makefile
  security: remove unneeded subdir-$(CONFIG_...)
  kbuild: sh: remove unused install script
  kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y
  kbuild: Switch to 'f' variants of integrated assembler flag
  kbuild: Shuffle blank line to improve comment meaning
  ...

1 files changed, 15 insertions, 0 deletions

diff --git a/scripts/kconfig/merge_config.sh b/scripts/kconfig/merge_config.sh
index 63c8565206a4..e5b46980c22a 100755
--- a/scripts/kconfig/merge_config.sh
+++ b/scripts/kconfig/merge_config.sh
@@ -28,6 +28,7 @@ usage() {
 	echo "  -r    list redundant entries when merging fragments"
 	echo "  -y    make builtin have precedence over modules"
 	echo "  -O    dir to put generated output files.  Consider setting \$KCONFIG_CONFIG instead."
+	echo "  -s    strict mode. Fail if the fragment redefines any value."
 	echo
 	echo "Used prefix: '$CONFIG_PREFIX'. You can redefine it with \$CONFIG_ environment variable."
 }
@@ -37,6 +38,7 @@ ALLTARGET=alldefconfig
 WARNREDUN=false
 BUILTIN=false
 OUTPUT=.
+STRICT=false
 CONFIG_PREFIX=${CONFIG_-CONFIG_}
 
 while true; do
@@ -75,6 +77,11 @@ while true; do
 		shift 2
 		continue
 		;;
+	"-s")
+		STRICT=true
+		shift
+		continue
+		;;
 	*)
 		break
 		;;
@@ -141,6 +148,9 @@ for ORIG_MERGE_FILE in $MERGE_LIST ; do
 			echo Previous  value: $PREV_VAL
 			echo New value:       $NEW_VAL
 			echo
+			if [ "$STRICT" = "true" ]; then
+				STRICT_MODE_VIOLATED=true
+			fi
 		elif [ "$WARNREDUN" = "true" ]; then
 			echo Value of $CFG is redundant by fragment $ORIG_MERGE_FILE:
 		fi
@@ -153,6 +163,11 @@ for ORIG_MERGE_FILE in $MERGE_LIST ; do
 	cat $MERGE_FILE >> $TMP_FILE
 done
 
+if [ "$STRICT_MODE_VIOLATED" = "true" ]; then
+	echo "The fragment redefined a value and strict mode had been passed."
+	exit 1
+fi
+
 if [ "$RUNMAKE" = "false" ]; then
 	cp -T -- "$TMP_FILE" "$KCONFIG_CONFIG"
 	echo "#"