Kbuild fixes for v5.2 (2nd)

- fix kselftest-merge to find config fragments in deeper directories
 
  - fix kconfig unit test, which was broken by SPDX tag addition
 
  - add + prefix to buildtar to suppress jobserver unavailable warning
 
  - fix checkstack.pl to recognize arch=arm64
 
  - suppress noisy warning from cc-cross-prefix
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Merge tag 'kbuild-fixes-v5.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull more Kbuild fixes from Masahiro Yamada:

 - fix kselftest-merge to find config fragments in deeper directories

 - fix kconfig unit test, which was broken by SPDX tag addition

 - add + prefix to buildtar to suppress jobserver unavailable warning

 - fix checkstack.pl to recognize arch=arm64

 - suppress noisy warning from cc-cross-prefix

* tag 'kbuild-fixes-v5.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: use more portable 'command -v' for cc-cross-prefix
  scripts/checkstack.pl: Fix arm64 wrong or unknown architecture
  kbuild: tar-pkg: enable communication with jobserver
  kconfig: tests: fix recursive inclusion unit test
  kbuild: teach kselftest-merge to find nested config files

Makefile

@@ -1228,9 +1228,8 @@ kselftest-clean:
 PHONY += kselftest-merge
 kselftest-merge:
 	$(if $(wildcard $(objtree)/.config),, $(error No .config exists, config your kernel first!))
-	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/kconfig/merge_config.sh \
-		-m $(objtree)/.config \
-		$(srctree)/tools/testing/selftests/*/config
+	$(Q)find $(srctree)/tools/testing/selftests -name config | \
+		xargs $(srctree)/scripts/kconfig/merge_config.sh -m $(objtree)/.config
 	+$(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig
 
 # ---------------------------------------------------------------------------

scripts/Kbuild.include

@@ -74,8 +74,13 @@ endef
 # Usage: CROSS_COMPILE := $(call cc-cross-prefix, m68k-linux-gnu- m68k-linux-)
 # Return first <prefix> where a <prefix>gcc is found in PATH.
 # If no gcc found in PATH with listed prefixes return nothing
+#
+# Note: '2>/dev/null' is here to force Make to invoke a shell. Otherwise, it
+# would try to directly execute the shell builtin 'command'. This workaround
+# should be kept for a long time since this issue was fixed only after the
+# GNU Make 4.2.1 release.
 cc-cross-prefix = $(firstword $(foreach c, $(filter-out -%, $(1)), \
-					$(if $(shell which $(c)gcc), $(c))))
+			$(if $(shell command -v $(c)gcc 2>/dev/null), $(c))))
 
 # output directory for tests below
 TMPOUT := $(if $(KBUILD_EXTMOD),$(firstword $(KBUILD_EXTMOD))/)

scripts/checkstack.pl

@@ -46,7 +46,7 @@ my (@stack, $re, $dre, $x, $xs, $funcre);
 	$x	= "[0-9a-f]";	# hex character
 	$xs	= "[0-9a-f ]";	# hex character or space
 	$funcre = qr/^$x* <(.*)>:$/;
-	if ($arch eq 'aarch64') {
+	if ($arch =~ '^(aarch|arm)64$') {
 		#ffffffc0006325cc:       a9bb7bfd        stp     x29, x30, [sp, #-80]!
 		#a110:       d11643ff        sub     sp, sp, #0x590
 		$re = qr/^.*stp.*sp, \#-([0-9]{1,8})\]\!/o;

scripts/kconfig/tests/err_recursive_inc/expected_stderr

@@ -1,6 +1,6 @@
 Recursive inclusion detected.
 Inclusion path:
   current file : Kconfig.inc1
-  included from: Kconfig.inc3:1
-  included from: Kconfig.inc2:3
-  included from: Kconfig.inc1:4
+  included from: Kconfig.inc3:2
+  included from: Kconfig.inc2:4
+  included from: Kconfig.inc1:5

scripts/package/Makefile

@@ -104,7 +104,7 @@ clean-dirs += $(objtree)/snap/
 # ---------------------------------------------------------------------------
 tar%pkg: FORCE
 	$(MAKE) -f $(srctree)/Makefile
-	$(CONFIG_SHELL) $(srctree)/scripts/package/buildtar $@
+	+$(CONFIG_SHELL) $(srctree)/scripts/package/buildtar $@
 
 clean-dirs += $(objtree)/tar-install/