Merge tag 'kbuild-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Remove the global -isystem compiler flag, which was made possible by
   the introduction of <linux/stdarg.h>

 - Improve the Kconfig help to print the location in the top menu level

 - Fix "FORCE prerequisite is missing" build warning for sparc

 - Add new build targets, tarzst-pkg and perf-tarzst-src-pkg, which
   generate a zstd-compressed tarball

 - Prevent gen_init_cpio tool from generating a corrupted cpio when
   KBUILD_BUILD_TIMESTAMP is set to 2106-02-07 or later

 - Misc cleanups

* tag 'kbuild-v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (28 commits)
  kbuild: use more subdir- for visiting subdirectories while cleaning
  sh: remove meaningless archclean line
  initramfs: Check timestamp to prevent broken cpio archive
  kbuild: split DEBUG_CFLAGS out to scripts/Makefile.debug
  gen_init_cpio: add static const qualifiers
  kbuild: Add make tarzst-pkg build option
  scripts: update the comments of kallsyms support
  sparc: Add missing "FORCE" target when using if_changed
  kconfig: refactor conf_touch_dep()
  kconfig: refactor conf_write_dep()
  kconfig: refactor conf_write_autoconf()
  kconfig: add conf_get_autoheader_name()
  kconfig: move sym_escape_string_value() to confdata.c
  kconfig: refactor listnewconfig code
  kconfig: refactor conf_write_symbol()
  kconfig: refactor conf_write_heading()
  kconfig: remove 'const' from the return type of sym_escape_string_value()
  kconfig: rename a variable in the lexer to a clearer name
  kconfig: narrow the scope of variables in the lexer
  kconfig: Create links to main menu items in search
  ...

Author: torvalds

Documentation/kbuild/makefiles.rst

@@ -1050,22 +1050,9 @@ is not sufficient this sometimes needs to be explicit.
 The above assignment instructs kbuild to descend down in the
 directory compressed/ when "make clean" is executed.
 
-To support the clean infrastructure in the Makefiles that build the
-final bootimage there is an optional target named archclean:
-
-	Example::
-
-		#arch/x86/Makefile
-		archclean:
-			$(Q)$(MAKE) $(clean)=arch/x86/boot
-
-When "make clean" is executed, make will descend down in arch/x86/boot,
-and clean as usual. The Makefile located in arch/x86/boot/ may use
-the subdir- trick to descend further down.
-
 Note 1: arch/$(SRCARCH)/Makefile cannot use "subdir-", because that file is
-included in the top level makefile, and the kbuild infrastructure
-is not operational at that point.
+included in the top level makefile. Instead, arch/$(SRCARCH)/Kbuild can use
+"subdir-".
 
 Note 2: All directories listed in core-y, libs-y, drivers-y and net-y will
 be visited during "make clean".

Makefile

@@ -850,44 +850,6 @@ ifdef CONFIG_ZERO_CALL_USED_REGS
 KBUILD_CFLAGS	+= -fzero-call-used-regs=used-gpr
 endif
 
-DEBUG_CFLAGS	:=
-
-ifdef CONFIG_DEBUG_INFO
-
-ifdef CONFIG_DEBUG_INFO_SPLIT
-DEBUG_CFLAGS	+= -gsplit-dwarf
-else
-DEBUG_CFLAGS	+= -g
-endif
-
-ifndef CONFIG_AS_IS_LLVM
-KBUILD_AFLAGS	+= -Wa,-gdwarf-2
-endif
-
-ifndef CONFIG_DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT
-dwarf-version-$(CONFIG_DEBUG_INFO_DWARF4) := 4
-dwarf-version-$(CONFIG_DEBUG_INFO_DWARF5) := 5
-DEBUG_CFLAGS	+= -gdwarf-$(dwarf-version-y)
-endif
-
-ifdef CONFIG_DEBUG_INFO_REDUCED
-DEBUG_CFLAGS	+= -fno-var-tracking
-ifdef CONFIG_CC_IS_GCC
-DEBUG_CFLAGS	+= -femit-struct-debug-baseonly
-endif
-endif
-
-ifdef CONFIG_DEBUG_INFO_COMPRESSED
-DEBUG_CFLAGS	+= -gz=zlib
-KBUILD_AFLAGS	+= -gz=zlib
-KBUILD_LDFLAGS	+= --compress-debug-sections=zlib
-endif
-
-endif # CONFIG_DEBUG_INFO
-
-KBUILD_CFLAGS += $(DEBUG_CFLAGS)
-export DEBUG_CFLAGS
-
 ifdef CONFIG_FUNCTION_TRACER
 ifdef CONFIG_FTRACE_MCOUNT_USE_CC
   CC_FLAGS_FTRACE	+= -mrecord-mcount
@@ -984,7 +946,7 @@ KBUILD_CFLAGS += -falign-functions=64
 endif
 
 # arch Makefile may override CC so keep this after arch Makefile is included
-NOSTDINC_FLAGS += -nostdinc -isystem $(shell $(CC) -print-file-name=include)
+NOSTDINC_FLAGS += -nostdinc
 
 # warn about C99 declaration after statement
 KBUILD_CFLAGS += -Wdeclaration-after-statement
@@ -1051,6 +1013,7 @@ KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=)
 
 # include additional Makefiles when needed
 include-y			:= scripts/Makefile.extrawarn
+include-$(CONFIG_DEBUG_INFO)	+= scripts/Makefile.debug
 include-$(CONFIG_KASAN)		+= scripts/Makefile.kasan
 include-$(CONFIG_KCSAN)		+= scripts/Makefile.kcsan
 include-$(CONFIG_UBSAN)		+= scripts/Makefile.ubsan

arch/alpha/Kbuild

@@ -1,3 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-y			+= kernel/ mm/
 obj-$(CONFIG_MATHEMU)	+= math-emu/
+
+# for cleaning
+subdir- += boot

arch/alpha/Makefile

@@ -55,9 +55,6 @@ $(boot)/vmlinux.gz: vmlinux
 bootimage bootpfile bootpzfile: vmlinux
 	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
 
-archclean:
-	$(Q)$(MAKE) $(clean)=$(boot)
-
 archheaders:
 	$(Q)$(MAKE) $(build)=arch/alpha/kernel/syscalls all
 

arch/arc/Kbuild

@@ -1,3 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 obj-y += kernel/
 obj-y += mm/
+
+# for cleaning
+subdir- += boot

arch/arc/Makefile

@@ -112,6 +112,3 @@ uImage: $(uimage-default-y)
 	@$(kecho) '  Image $(boot)/uImage is ready'
 
 CLEAN_FILES += $(boot)/uImage
-
-archclean:
-	$(Q)$(MAKE) $(clean)=$(boot)

arch/arm/Kbuild

@@ -9,3 +9,6 @@ obj-y				+= kernel/ mm/ common/
 obj-y				+= probes/
 obj-y				+= net/
 obj-y				+= crypto/
+
+# for cleaning
+subdir- += boot

arch/arm/Makefile

@@ -318,10 +318,6 @@ ifeq ($(CONFIG_VDSO),y)
 	$(Q)$(MAKE) $(build)=arch/arm/vdso $@
 endif
 
-# We use MRPROPER_FILES and CLEAN_FILES now
-archclean:
-	$(Q)$(MAKE) $(clean)=$(boot)
-
 # My testing targets (bypasses dependencies)
 bp:;	$(Q)$(MAKE) $(build)=$(boot) MACHINE=$(MACHINE) $(boot)/bootpImage
 

arch/arm64/Kbuild

@@ -4,3 +4,6 @@ obj-$(CONFIG_KVM)	+= kvm/
 obj-$(CONFIG_XEN)	+= xen/
 obj-$(subst m,y,$(CONFIG_HYPERV))	+= hyperv/
 obj-$(CONFIG_CRYPTO)	+= crypto/
+
+# for cleaning
+subdir- += boot

arch/arm64/Makefile

@@ -182,13 +182,6 @@ ifeq ($(CONFIG_ARM64_USE_LSE_ATOMICS),y)
   endif
 endif
 
-
-# We use MRPROPER_FILES and CLEAN_FILES now
-archclean:
-	$(Q)$(MAKE) $(clean)=$(boot)
-	$(Q)$(MAKE) $(clean)=arch/arm64/kernel/vdso
-	$(Q)$(MAKE) $(clean)=arch/arm64/kernel/vdso32
-
 ifeq ($(KBUILD_EXTMOD),)
 # We need to generate vdso-offsets.h before compiling certain files in kernel/.
 # In order to do that, we should use the archprepare target, but we can't since