Merge tag 'kbuild-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Increase the -falign-functions alignment for the debug option.

 - Remove ugly libelf checks from the top Makefile.

 - Make the silent build (-s) more silent.

 - Re-compile the kernel if KBUILD_BUILD_TIMESTAMP is specified.

 - Various script cleanups

* tag 'kbuild-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (27 commits)
  scripts: add generic syscallnr.sh
  scripts: check duplicated syscall number in syscall table
  sparc: syscalls: use pattern rules to generate syscall headers
  parisc: syscalls: use pattern rules to generate syscall headers
  nds32: add arch/nds32/boot/.gitignore
  kbuild: mkcompile_h: consider timestamp if KBUILD_BUILD_TIMESTAMP is set
  kbuild: modpost: Explicitly warn about unprototyped symbols
  kbuild: remove trailing slashes from $(KBUILD_EXTMOD)
  kconfig.h: explain IS_MODULE(), IS_ENABLED()
  kconfig: constify long_opts
  scripts/setlocalversion: simplify the short version part
  scripts/setlocalversion: factor out 12-chars hash construction
  scripts/setlocalversion: add more comments to -dirty flag detection
  scripts/setlocalversion: remove workaround for old make-kpkg
  scripts/setlocalversion: remove mercurial, svn and git-svn supports
  kbuild: clean up ${quiet} checks in shell scripts
  kbuild: sink stdout from cmd for silent build
  init: use $(call cmd,) for generating include/generated/compile.h
  kbuild: merge scripts/mkmakefile to top Makefile
  sh: move core-y in arch/sh/Makefile to arch/sh/Kbuild
  ...

Author: torvalds

Makefile

@@ -129,6 +129,11 @@ endif
 $(if $(word 2, $(KBUILD_EXTMOD)), \
 	$(error building multiple external modules is not supported))
 
+# Remove trailing slashes
+ifneq ($(filter %/, $(KBUILD_EXTMOD)),)
+KBUILD_EXTMOD := $(shell dirname $(KBUILD_EXTMOD).)
+endif
+
 export KBUILD_EXTMOD
 
 # Kbuild will save output files in the current working directory.
@@ -544,14 +549,21 @@ scripts_basic:
 	$(Q)rm -f .tmp_quiet_recordmcount
 
 PHONY += outputmakefile
+ifdef building_out_of_srctree
 # Before starting out-of-tree build, make sure the source tree is clean.
 # outputmakefile generates a Makefile in the output directory, if using a
 # separate output directory. This allows convenient use of make in the
 # output directory.
 # At the same time when output Makefile generated, generate .gitignore to
 # ignore whole output directory
+
+quiet_cmd_makefile = GEN     Makefile
+      cmd_makefile = { \
+	echo "\# Automatically generated by $(srctree)/Makefile: don't edit"; \
+	echo "include $(srctree)/Makefile"; \
+	} > Makefile
+
 outputmakefile:
-ifdef building_out_of_srctree
 	$(Q)if [ -f $(srctree)/.config -o \
 		 -d $(srctree)/include/config -o \
 		 -d $(srctree)/arch/$(SRCARCH)/include/generated ]; then \
@@ -562,7 +574,7 @@ ifdef building_out_of_srctree
 		false; \
 	fi
 	$(Q)ln -fsn $(srctree) source
-	$(Q)$(CONFIG_SHELL) $(srctree)/scripts/mkmakefile $(srctree)
+	$(call cmd,makefile)
 	$(Q)test -e .gitignore || \
 	{ echo "# this is build directory, ignore it"; echo "*"; } > .gitignore
 endif
@@ -658,7 +670,7 @@ endif
 
 ifeq ($(KBUILD_EXTMOD),)
 # Objects we will link into vmlinux / subdirs we need to visit
-core-y		:= init/ usr/
+core-y		:= init/ usr/ arch/$(SRCARCH)/
 drivers-y	:= drivers/ sound/
 drivers-$(CONFIG_SAMPLES) += samples/
 drivers-$(CONFIG_NET) += net/
@@ -961,8 +973,8 @@ KBUILD_CFLAGS	+= $(CC_FLAGS_CFI)
 export CC_FLAGS_CFI
 endif
 
-ifdef CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_32B
-KBUILD_CFLAGS += -falign-functions=32
+ifdef CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_64B
+KBUILD_CFLAGS += -falign-functions=64
 endif
 
 # arch Makefile may override CC so keep this after arch Makefile is included
@@ -1089,41 +1101,6 @@ export INSTALL_DTBS_PATH ?= $(INSTALL_PATH)/dtbs/$(KERNELRELEASE)
 MODLIB	= $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
 export MODLIB
 
-HOST_LIBELF_LIBS = $(shell pkg-config libelf --libs 2>/dev/null || echo -lelf)
-
-has_libelf = $(call try-run,\
-               echo "int main() {}" | $(HOSTCC) $(KBUILD_HOSTLDFLAGS) -xc -o /dev/null $(HOST_LIBELF_LIBS) -,1,0)
-
-ifdef CONFIG_STACK_VALIDATION
-  ifeq ($(has_libelf),1)
-    objtool_target := tools/objtool FORCE
-  else
-    SKIP_STACK_VALIDATION := 1
-    export SKIP_STACK_VALIDATION
-  endif
-endif
-
-PHONY += resolve_btfids_clean
-
-resolve_btfids_O = $(abspath $(objtree))/tools/bpf/resolve_btfids
-
-# tools/bpf/resolve_btfids directory might not exist
-# in output directory, skip its clean in that case
-resolve_btfids_clean:
-ifneq ($(wildcard $(resolve_btfids_O)),)
-	$(Q)$(MAKE) -sC $(srctree)/tools/bpf/resolve_btfids O=$(resolve_btfids_O) clean
-endif
-
-ifdef CONFIG_BPF
-ifdef CONFIG_DEBUG_INFO_BTF
-  ifeq ($(has_libelf),1)
-    resolve_btfids_target := tools/bpf/resolve_btfids FORCE
-  else
-    ERROR_RESOLVE_BTFIDS := 1
-  endif
-endif # CONFIG_DEBUG_INFO_BTF
-endif # CONFIG_BPF
-
 PHONY += prepare0
 
 export extmod_prefix = $(if $(KBUILD_EXTMOD),$(KBUILD_EXTMOD)/)
@@ -1235,7 +1212,7 @@ prepare0: archprepare
 	$(Q)$(MAKE) $(build)=.
 
 # All the preparing..
-prepare: prepare0 prepare-objtool prepare-resolve_btfids
+prepare: prepare0
 
 PHONY += remove-stale-files
 remove-stale-files:
@@ -1252,26 +1229,6 @@ uapi-asm-generic:
 	$(Q)$(MAKE) $(asm-generic)=arch/$(SRCARCH)/include/generated/uapi/asm \
 	generic=include/uapi/asm-generic
 
-PHONY += prepare-objtool prepare-resolve_btfids
-prepare-objtool: $(objtool_target)
-ifeq ($(SKIP_STACK_VALIDATION),1)
-ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL
-	@echo "error: Cannot generate __mcount_loc for CONFIG_DYNAMIC_FTRACE=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel" >&2
-	@false
-endif
-ifdef CONFIG_UNWINDER_ORC
-	@echo "error: Cannot generate ORC metadata for CONFIG_UNWINDER_ORC=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel" >&2
-	@false
-else
-	@echo "warning: Cannot use CONFIG_STACK_VALIDATION=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel" >&2
-endif
-endif
-
-prepare-resolve_btfids: $(resolve_btfids_target)
-ifeq ($(ERROR_RESOLVE_BTFIDS),1)
-	@echo "error: Cannot resolve BTF IDs for CONFIG_DEBUG_INFO_BTF, please install libelf-dev, libelf-devel or elfutils-libelf-devel" >&2
-	@false
-endif
 # Generate some files
 # ---------------------------------------------------------------------------
 
@@ -1359,6 +1316,43 @@ PHONY += scripts_unifdef
 scripts_unifdef: scripts_basic
 	$(Q)$(MAKE) $(build)=scripts scripts/unifdef
 
+# ---------------------------------------------------------------------------
+# Tools
+
+ifdef CONFIG_STACK_VALIDATION
+prepare: tools/objtool
+endif
+
+ifdef CONFIG_BPF
+ifdef CONFIG_DEBUG_INFO_BTF
+prepare: tools/bpf/resolve_btfids
+endif
+endif
+
+PHONY += resolve_btfids_clean
+
+resolve_btfids_O = $(abspath $(objtree))/tools/bpf/resolve_btfids
+
+# tools/bpf/resolve_btfids directory might not exist
+# in output directory, skip its clean in that case
+resolve_btfids_clean:
+ifneq ($(wildcard $(resolve_btfids_O)),)
+	$(Q)$(MAKE) -sC $(srctree)/tools/bpf/resolve_btfids O=$(resolve_btfids_O) clean
+endif
+
+# Clear a bunch of variables before executing the submake
+ifeq ($(quiet),silent_)
+tools_silent=s
+endif
+
+tools/: FORCE
+	$(Q)mkdir -p $(objtree)/tools
+	$(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(abspath $(objtree)) subdir=tools -C $(srctree)/tools/
+
+tools/%: FORCE
+	$(Q)mkdir -p $(objtree)/tools
+	$(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(abspath $(objtree)) subdir=tools -C $(srctree)/tools/ $*
+
 # ---------------------------------------------------------------------------
 # Kernel selftest
 
@@ -1959,20 +1953,6 @@ kernelversion:
 image_name:
 	@echo $(KBUILD_IMAGE)
 
-# Clear a bunch of variables before executing the submake
-
-ifeq ($(quiet),silent_)
-tools_silent=s
-endif
-
-tools/: FORCE
-	$(Q)mkdir -p $(objtree)/tools
-	$(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(abspath $(objtree)) subdir=tools -C $(srctree)/tools/
-
-tools/%: FORCE
-	$(Q)mkdir -p $(objtree)/tools
-	$(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(abspath $(objtree)) subdir=tools -C $(srctree)/tools/ $*
-
 quiet_cmd_rmfiles = $(if $(wildcard $(rm-files)),CLEAN   $(wildcard $(rm-files)))
       cmd_rmfiles = rm -rf $(rm-files)
 

arch/alpha/Kbuild

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-y			+= kernel/ mm/
+obj-$(CONFIG_MATHEMU)	+= math-emu/

arch/alpha/Makefile

@@ -38,8 +38,6 @@ KBUILD_CFLAGS += $(cflags-y) -Wa,-mev6
 
 head-y := arch/alpha/kernel/head.o
 
-core-y				+= arch/alpha/kernel/ arch/alpha/mm/
-core-$(CONFIG_MATHEMU)		+= arch/alpha/math-emu/
 libs-y				+= arch/alpha/lib/
 
 # export what is needed by arch/alpha/boot/Makefile

arch/arc/Makefile

@@ -85,9 +85,6 @@ KBUILD_LDFLAGS	+= $(ldflags-y)
 
 head-y		:= arch/arc/kernel/head.o
 
-# See arch/arc/Kbuild for content of core part of the kernel
-core-y		+= arch/arc/
-
 # w/o this dtb won't embed into kernel binary
 core-y		+= arch/arc/boot/dts/
 

arch/arm/Makefile

@@ -252,7 +252,6 @@ endif
 
 export	TEXT_OFFSET GZFLAGS MMUEXT
 
-core-y				+= arch/arm/
 # If we have a machine-specific directory, then include it in the build.
 core-y				+= $(machdirs) $(platdirs)
 

arch/arm64/Makefile

@@ -149,7 +149,6 @@ KBUILD_CFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
 KBUILD_CPPFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
 KBUILD_AFLAGS += -DKASAN_SHADOW_SCALE_SHIFT=$(KASAN_SHADOW_SCALE_SHIFT)
 
-core-y		+= arch/arm64/
 libs-y		:= arch/arm64/lib/ $(libs-y)
 libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
 

arch/csky/Kbuild

@@ -0,0 +1 @@
+# SPDX-License-Identifier: GPL-2.0-only

arch/h8300/Kbuild

@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-y	+= kernel/ mm/ boot/dts/

arch/h8300/Makefile

@@ -30,9 +30,6 @@ ifeq ($(CROSS_COMPILE),)
 CROSS_COMPILE := $(call cc-cross-prefix, h8300-unknown-linux- h8300-linux-)
 endif
 
-core-y	+= arch/$(ARCH)/kernel/ arch/$(ARCH)/mm/
-core-y	+= arch/$(ARCH)/boot/dts/
-
 libs-y	+= arch/$(ARCH)/lib/
 
 boot := arch/h8300/boot

arch/hexagon/Kbuild

@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-y += kernel/ mm/ lib/