[PATCH 00/15] kbuild: various cleanups

[PATCH 00/15] kbuild: various cleanups

[Masahiro Yamada]

  - Avoid updating init/built-in.a twice
  - Run modpost just once instead of twice
  - Link vmlinux and modules in parallel
  - Remove head-y syntax

These are ground works to make the further refactoring possible.

This patch set is applicable after the following series:
  https://patchwork.kernel.org/project/linux-kbuild/list/?series=669437


Masahiro Yamada (15):
  kbuild: remove duplicated dependency between modules and modules_check
  kbuild: refactor single builds of *.ko
  kbuild: move 'PHONY += modules_prepare' to the common part
  init/version.c: remove #include <linux/version.h>
  kbuild: build init/built-in.a just once
  kbuild: generate include/generated/compile.h in top Makefile
  scripts/mkcompile_h: move LC_ALL=C to '$LD -v'
  Revert "kbuild: Make scripts/compile.h when sh != bash"
  kbuild: rename modules.order in sub-directories to .modules.order
  kbuild: move core-y in top Makefile to ./Kbuild
  kbuild: move .vmlinux.objs rule to Makefile.modpost
  kbuild: move vmlinux.o rule to the top Makefile
  kbuild: unify two modpost invocations
  kbuild: use obj-y instead extra-y for objects placed at the head
  kbuild: remove head-y syntax

 Documentation/kbuild/makefiles.rst          |  27 +----
 Kbuild                                      |  16 +++
 Makefile                                    | 120 ++++++++++++--------
 arch/alpha/Makefile                         |   2 -
 arch/alpha/kernel/Makefile                  |   4 +-
 arch/arc/Makefile                           |   2 -
 arch/arc/kernel/Makefile                    |   4 +-
 arch/arm/Makefile                           |   3 -
 arch/arm/kernel/Makefile                    |   4 +-
 arch/arm64/Makefile                         |   3 -
 arch/arm64/kernel/Makefile                  |   4 +-
 arch/csky/Makefile                          |   2 -
 arch/csky/kernel/Makefile                   |   4 +-
 arch/hexagon/Makefile                       |   2 -
 arch/hexagon/kernel/Makefile                |   3 +-
 arch/ia64/Makefile                          |   1 -
 arch/ia64/kernel/Makefile                   |   4 +-
 arch/loongarch/Makefile                     |   2 -
 arch/loongarch/kernel/Makefile              |   4 +-
 arch/m68k/68000/Makefile                    |   2 +-
 arch/m68k/Makefile                          |   9 --
 arch/m68k/coldfire/Makefile                 |   2 +-
 arch/m68k/kernel/Makefile                   |  21 ++--
 arch/microblaze/Makefile                    |   1 -
 arch/microblaze/kernel/Makefile             |   4 +-
 arch/mips/Makefile                          |   2 -
 arch/mips/kernel/Makefile                   |   4 +-
 arch/nios2/Makefile                         |   1 -
 arch/nios2/kernel/Makefile                  |   2 +-
 arch/openrisc/Makefile                      |   2 -
 arch/openrisc/kernel/Makefile               |   4 +-
 arch/parisc/Makefile                        |   2 -
 arch/parisc/kernel/Makefile                 |   4 +-
 arch/powerpc/Makefile                       |  12 --
 arch/powerpc/kernel/Makefile                |  22 ++--
 arch/riscv/Makefile                         |   2 -
 arch/riscv/kernel/Makefile                  |   2 +-
 arch/s390/Makefile                          |   2 -
 arch/s390/boot/version.c                    |   1 +
 arch/s390/kernel/Makefile                   |   4 +-
 arch/sh/Makefile                            |   2 -
 arch/sh/kernel/Makefile                     |   4 +-
 arch/sparc/Makefile                         |   2 -
 arch/sparc/kernel/Makefile                  |   3 +-
 arch/x86/Makefile                           |   5 -
 arch/x86/boot/compressed/kaslr.c            |   1 +
 arch/x86/boot/version.c                     |   1 +
 arch/x86/kernel/Makefile                    |  10 +-
 arch/xtensa/Makefile                        |   2 -
 arch/xtensa/kernel/Makefile                 |   4 +-
 init/Makefile                               |  55 ++++++---
 init/build-version                          |  10 ++
 init/version-timestamp.c                    |  31 +++++
 init/version.c                              |  37 +++---
 scripts/Makefile.build                      |  20 ++--
 scripts/Makefile.lib                        |   8 +-
 scripts/Makefile.modfinal                   |   2 +-
 scripts/Makefile.modpost                    | 112 ++++++++----------
 scripts/Makefile.vmlinux_o                  |   6 +-
 scripts/clang-tools/gen_compile_commands.py |  19 +---
 scripts/head-object-list.txt                |  53 +++++++++
 scripts/link-vmlinux.sh                     |  51 ++-------
 scripts/mkcompile_h                         |  96 ++--------------
 63 files changed, 393 insertions(+), 457 deletions(-)
 create mode 100755 init/build-version
 create mode 100644 init/version-timestamp.c
 create mode 100644 scripts/head-object-list.txt

-- 
2.34.1

[PATCH 01/15] kbuild: remove duplicated dependency between modules and modules_check

[Masahiro Yamada]

The dependency, "modules: modules_check" is specified twice.
Commit 1a998be620a1 ("kbuild: check module name conflict for external
modules as well") missed to clean it up.

'PHONY += modules' also appears twice.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 Makefile | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Makefile b/Makefile
index 7c955e906445..f04126181885 100644
--- a/Makefile
+++ b/Makefile
@@ -1436,8 +1436,7 @@ endif
 # Build modules
 #
 
-PHONY += modules
-modules: $(if $(KBUILD_BUILTIN),vmlinux) modules_check modules_prepare
+modules: $(if $(KBUILD_BUILTIN),vmlinux) modules_prepare
 
 cmd_modules_order = cat $(real-prereqs) > $@
 
-- 
2.34.1

[PATCH 02/15] kbuild: refactor single builds of *.ko

[Masahiro Yamada]

Remove the potentially invalid modules.order instead of using
the temporary file.

Also, KBUILD_MODULES is don't care for single builds. No need to
cancel it.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 Makefile | 16 ++++------------
 1 file changed, 4 insertions(+), 12 deletions(-)

diff --git a/Makefile b/Makefile
index f04126181885..badd318c5524 100644
--- a/Makefile
+++ b/Makefile
@@ -1787,6 +1787,8 @@ modules modules_install:
 	@echo >&2 '***'
 	@exit 1
 
+KBUILD_MODULES :=
+
 endif # CONFIG_MODULES
 
 # Single targets
@@ -1813,18 +1815,12 @@ $(single-ko): single_modpost
 $(single-no-ko): descend
 	@:
 
-ifeq ($(KBUILD_EXTMOD),)
-# For the single build of in-tree modules, use a temporary file to avoid
-# the situation of modules_install installing an invalid modules.order.
-MODORDER := .modules.tmp
-endif
-
+# Remove MODORDER when done because it is not the real one.
 PHONY += single_modpost
 single_modpost: $(single-no-ko) modules_prepare
 	$(Q){ $(foreach m, $(single-ko), echo $(extmod_prefix)$m;) } > $(MODORDER)
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
-
-KBUILD_MODULES := 1
+	$(Q)rm -f $(MODORDER)
 
 export KBUILD_SINGLE_TARGETS := $(addprefix $(extmod_prefix), $(single-no-ko))
 
@@ -1834,10 +1830,6 @@ build-dirs := $(foreach d, $(build-dirs), \
 
 endif
 
-ifndef CONFIG_MODULES
-KBUILD_MODULES :=
-endif
-
 # Handle descending into subdirectories listed in $(build-dirs)
 # Preset locale variables to speed up the build process. Limit locale
 # tweaks to this spot to avoid wrong language settings when running
-- 
2.34.1

[PATCH 03/15] kbuild: move 'PHONY += modules_prepare' to the common part

[Masahiro Yamada]

Unify the code between in-tree builds and external module builds.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 Makefile | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index badd318c5524..54e481162608 100644
--- a/Makefile
+++ b/Makefile
@@ -1446,7 +1446,6 @@ modules.order: $(subdir-modorder) FORCE
 targets += modules.order
 
 # Target to prepare building external modules
-PHONY += modules_prepare
 modules_prepare: prepare
 	$(Q)$(MAKE) $(build)=scripts scripts/module.lds
 
@@ -1747,15 +1746,12 @@ help:
 	@echo  '  clean           - remove generated files in module directory only'
 	@echo  ''
 
-# no-op for external module builds
-PHONY += modules_prepare
-
 endif # KBUILD_EXTMOD
 
 # ---------------------------------------------------------------------------
 # Modules
 
-PHONY += modules modules_install
+PHONY += modules modules_install modules_prepare
 
 ifdef CONFIG_MODULES
 
-- 
2.34.1

[PATCH 04/15] init/version.c: remove #include <linux/version.h>

[Masahiro Yamada]

This is unneeded since commit 073a9ecb3a73 ("init/version.c: remove
Version_<LINUX_VERSION_CODE> symbol").

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 init/version.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/init/version.c b/init/version.c
index b7f9559d417c..3391c4051bf3 100644
--- a/init/version.c
+++ b/init/version.c
@@ -16,7 +16,6 @@
 #include <linux/uts.h>
 #include <linux/utsname.h>
 #include <generated/utsrelease.h>
-#include <linux/version.h>
 #include <linux/proc_ns.h>
 
 struct uts_namespace init_uts_ns = {
-- 
2.34.1

[PATCH 05/15] kbuild: build init/built-in.a just once

[Masahiro Yamada]

Kbuild builds init/built-in.a twice; first during the ordinary
directory descending, second from scripts/link-vmlinux.sh.

We do this because UTS_VERSION contains the build version and the
timestamp. We cannot update it during the normal directory traversal
since we do not yet know if we need to update vmlinux. UTS_VERSION is
temporarily calculated, but omitted from the update check. Otherwise,
vmlinux would be rebuilt every time.

When Kbuild results in running link-vmlinux.sh, it increments the
version number in the .version file and takes the timestamp at that
time to really fix UTS_VERSION.

However, updating the same file twice is a footgun. To avoid nasty
timestamp issues, all build artifacts that depend on init/built-in.a
must be atomically generated in link-vmlinux.sh, where some of them
do not need rebuilding.

To fix this issue, this commit changes as follows:

[1] Split UTS_VERSION out to include/generated/utsversion.h from
    include/generated/compile.h

    include/generated/utsversion.h is generated just before the
    vmlinux link. It is generated under include/generated/ because
    some decompressors (s390, x86) use UTS_VERSION.

[2] Split init_uts_ns and linux_banner out to init/version-timestamp.c
    from init/version.c

    init_uts_ns and linux_banner contain UTS_VERSION. During the ordinary
    directory descending, they are compiled with __weak and used to
    determine if vmlinux needs relinking. Just before the vmlinux link,
    they are compiled without __weak to embed the real version and
    timestamp.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 arch/s390/boot/version.c         |  1 +
 arch/x86/boot/compressed/kaslr.c |  1 +
 arch/x86/boot/version.c          |  1 +
 init/Makefile                    | 53 ++++++++++++++-----
 init/build-version               | 10 ++++
 init/version-timestamp.c         | 31 +++++++++++
 init/version.c                   | 36 +++++--------
 scripts/link-vmlinux.sh          | 17 ++----
 scripts/mkcompile_h              | 89 ++++----------------------------
 9 files changed, 112 insertions(+), 127 deletions(-)
 create mode 100755 init/build-version
 create mode 100644 init/version-timestamp.c

diff --git a/arch/s390/boot/version.c b/arch/s390/boot/version.c
index d32e58bdda6a..fd32f038777f 100644
--- a/arch/s390/boot/version.c
+++ b/arch/s390/boot/version.c
@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
+#include <generated/utsversion.h>
 #include <generated/utsrelease.h>
 #include <generated/compile.h>
 #include "boot.h"
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 4a3f223973f4..e476bcbd9b42 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -29,6 +29,7 @@
 #include <linux/uts.h>
 #include <linux/utsname.h>
 #include <linux/ctype.h>
+#include <generated/utsversion.h>
 #include <generated/utsrelease.h>
 
 #define _SETUP
diff --git a/arch/x86/boot/version.c b/arch/x86/boot/version.c
index a1aaaf6c06a6..945383f0f606 100644
--- a/arch/x86/boot/version.c
+++ b/arch/x86/boot/version.c
@@ -11,6 +11,7 @@
  */
 
 #include "boot.h"
+#include <generated/utsversion.h>
 #include <generated/utsrelease.h>
 #include <generated/compile.h>
 
diff --git a/init/Makefile b/init/Makefile
index d82623d7fc8e..63f53d210cad 100644
--- a/init/Makefile
+++ b/init/Makefile
@@ -19,20 +19,47 @@ mounts-y			:= do_mounts.o
 mounts-$(CONFIG_BLK_DEV_RAM)	+= do_mounts_rd.o
 mounts-$(CONFIG_BLK_DEV_INITRD)	+= do_mounts_initrd.o
 
-# dependencies on generated files need to be listed explicitly
-$(obj)/version.o: include/generated/compile.h
+#
+# UTS_VERSION
+#
+
+smp-flag-$(CONFIG_SMP)			:= SMP
+preempt-flag-$(CONFIG_PREEMPT_BUILD)	:= PREEMPT
+preempt-flag-$(CONFIG_PREEMPT_DYNAMIC)	:= PREEMPT_DYNAMIC
+preempt-flag-$(CONFIG_PREEMPT_RT)	:= PREEMPT_RT
+
+build-version = $(or $(KBUILD_BUILD_VERSION), $(build-version-auto))
+build-timestamp = $(or $(KBUILD_BUILD_TIMESTAMP), $(build-timestamp-auto))
+
+# Maximum length of UTS_VERSION is 64 chars
+filechk_uts_version = \
+	utsver=$$(echo '$(pound)'"$(build-version)" $(smp-flag-y) $(preempt-flag-y) "$(build-timestamp)" | cut -b -64); \
+	echo '$(pound)'define UTS_VERSION \""$${utsver}"\"
+
+#
+# Build version.c with temporary UTS_VERSION
+#
+
+$(obj)/utsversion-tmp.h: FORCE
+	$(call filechk,uts_version)
 
-# compile.h changes depending on hostname, generation number, etc,
-# so we regenerate it always.
-# mkcompile_h will make sure to only update the
-# actual file if its content has changed.
+$(obj)/version.o: include/generated/compile.h $(obj)/utsversion-tmp.h
+CFLAGS_version.o := -include $(obj)/utsversion-tmp.h
 
-quiet_cmd_compile.h = CHK     $@
-      cmd_compile.h = \
-	$(CONFIG_SHELL) $(srctree)/scripts/mkcompile_h $@	\
-	"$(UTS_MACHINE)" "$(CONFIG_SMP)" "$(CONFIG_PREEMPT_BUILD)"	\
-	"$(CONFIG_PREEMPT_DYNAMIC)" "$(CONFIG_PREEMPT_RT)" \
-	"$(CONFIG_CC_VERSION_TEXT)" "$(LD)"
+filechk_compile.h = $(srctree)/scripts/mkcompile_h \
+	"$(UTS_MACHINE)" "$(CONFIG_CC_VERSION_TEXT)" "$(LD)"
 
 include/generated/compile.h: FORCE
-	$(call cmd,compile.h)
+	$(call filechk,compile.h)
+
+#
+# Build version-timestamp.c with final UTS_VERSION
+#
+
+include/generated/utsversion.h: build-version-auto = $(shell $(srctree)/$(src)/build-version)
+include/generated/utsversion.h: build-timestamp-auto = $(shell LC_ALL=C date)
+include/generated/utsversion.h: FORCE
+	$(call filechk,uts_version)
+
+$(obj)/version-timestamp.o: include/generated/utsversion.h
+CFLAGS_version-timestamp.o := -include include/generated/utsversion.h
diff --git a/init/build-version b/init/build-version
new file mode 100755
index 000000000000..39225104f14d
--- /dev/null
+++ b/init/build-version
@@ -0,0 +1,10 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-only
+
+VERSION=$(cat .version) 2>/dev/null &&
+VERSION=$(expr $VERSION + 1) 2>/dev/null ||
+VERSION=1
+
+echo ${VERSION} > .version
+
+echo ${VERSION}
diff --git a/init/version-timestamp.c b/init/version-timestamp.c
new file mode 100644
index 000000000000..179e93bae539
--- /dev/null
+++ b/init/version-timestamp.c
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <generated/compile.h>
+#include <generated/utsrelease.h>
+#include <linux/version.h>
+#include <linux/proc_ns.h>
+#include <linux/refcount.h>
+#include <linux/uts.h>
+#include <linux/utsname.h>
+
+struct uts_namespace init_uts_ns = {
+	.ns.count = REFCOUNT_INIT(2),
+	.name = {
+		.sysname	= UTS_SYSNAME,
+		.nodename	= UTS_NODENAME,
+		.release	= UTS_RELEASE,
+		.version	= UTS_VERSION,
+		.machine	= UTS_MACHINE,
+		.domainname	= UTS_DOMAINNAME,
+	},
+	.user_ns = &init_user_ns,
+	.ns.inum = PROC_UTS_INIT_INO,
+#ifdef CONFIG_UTS_NS
+	.ns.ops = &utsns_operations,
+#endif
+};
+
+/* FIXED STRINGS! Don't touch! */
+const char linux_banner[] =
+	"Linux version " UTS_RELEASE " (" LINUX_COMPILE_BY "@"
+	LINUX_COMPILE_HOST ") (" LINUX_COMPILER ") " UTS_VERSION "\n";
diff --git a/init/version.c b/init/version.c
index 3391c4051bf3..01d4ab05f0ba 100644
--- a/init/version.c
+++ b/init/version.c
@@ -18,24 +18,6 @@
 #include <generated/utsrelease.h>
 #include <linux/proc_ns.h>
 
-struct uts_namespace init_uts_ns = {
-	.ns.count = REFCOUNT_INIT(2),
-	.name = {
-		.sysname	= UTS_SYSNAME,
-		.nodename	= UTS_NODENAME,
-		.release	= UTS_RELEASE,
-		.version	= UTS_VERSION,
-		.machine	= UTS_MACHINE,
-		.domainname	= UTS_DOMAINNAME,
-	},
-	.user_ns = &init_user_ns,
-	.ns.inum = PROC_UTS_INIT_INO,
-#ifdef CONFIG_UTS_NS
-	.ns.ops = &utsns_operations,
-#endif
-};
-EXPORT_SYMBOL_GPL(init_uts_ns);
-
 static int __init early_hostname(char *arg)
 {
 	size_t bufsize = sizeof(init_uts_ns.name.nodename);
@@ -51,11 +33,6 @@ static int __init early_hostname(char *arg)
 }
 early_param("hostname", early_hostname);
 
-/* FIXED STRINGS! Don't touch! */
-const char linux_banner[] =
-	"Linux version " UTS_RELEASE " (" LINUX_COMPILE_BY "@"
-	LINUX_COMPILE_HOST ") (" LINUX_COMPILER ") " UTS_VERSION "\n";
-
 const char linux_proc_banner[] =
 	"%s version %s"
 	" (" LINUX_COMPILE_BY "@" LINUX_COMPILE_HOST ")"
@@ -63,3 +40,16 @@ const char linux_proc_banner[] =
 
 BUILD_SALT;
 BUILD_LTO_INFO;
+
+/*
+ * init_uts_ns and linux_banner contain the build version and timestamp,
+ * which are really fixed at the very last step of build process.
+ * They are compiled with __weak first, and without __weak later.
+ */
+
+struct uts_namespace init_uts_ns __weak;
+const char linux_banner[] __weak;
+
+#include "version-timestamp.c"
+
+EXPORT_SYMBOL_GPL(init_uts_ns);
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index eecc1863e556..8d982574145a 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -75,6 +75,8 @@ vmlinux_link()
 		objs="${objs} .vmlinux.export.o"
 	fi
 
+	objs="${objs} init/version-timestamp.o"
+
 	if [ "${SRCARCH}" = "um" ]; then
 		wl=-Wl,
 		ld="${CC}"
@@ -213,19 +215,6 @@ if [ "$1" = "clean" ]; then
 	exit 0
 fi
 
-# Update version
-info GEN .version
-if [ -r .version ]; then
-	VERSION=$(expr 0$(cat .version) + 1)
-	echo $VERSION > .version
-else
-	rm -f .version
-	echo 1 > .version
-fi;
-
-# final build of init/
-${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init need-builtin=1
-
 #link vmlinux.o
 ${MAKE} -f "${srctree}/scripts/Makefile.vmlinux_o"
 
@@ -260,6 +249,8 @@ if is_enabled CONFIG_MODULES; then
 	${MAKE} -f "${srctree}/scripts/Makefile.vmlinux" .vmlinux.export.o
 fi
 
+${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init init/version-timestamp.o
+
 btf_vmlinux_bin_o=""
 if is_enabled CONFIG_DEBUG_INFO_BTF; then
 	btf_vmlinux_bin_o=.btf.vmlinux.bin.o
diff --git a/scripts/mkcompile_h b/scripts/mkcompile_h
index ca40a5258c87..f1a820d49e53 100755
--- a/scripts/mkcompile_h
+++ b/scripts/mkcompile_h
@@ -1,14 +1,9 @@
 #!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
 
-TARGET=$1
-ARCH=$2
-SMP=$3
-PREEMPT=$4
-PREEMPT_DYNAMIC=$5
-PREEMPT_RT=$6
-CC_VERSION="$7"
-LD=$8
+UTS_MACHINE=$1
+CC_VERSION="$2"
+LD=$3
 
 # Do not expand names
 set -f
@@ -17,17 +12,6 @@ set -f
 LC_ALL=C
 export LC_ALL
 
-if [ -z "$KBUILD_BUILD_VERSION" ]; then
-	VERSION=$(cat .version 2>/dev/null || echo 1)
-else
-	VERSION=$KBUILD_BUILD_VERSION
-fi
-
-if [ -z "$KBUILD_BUILD_TIMESTAMP" ]; then
-	TIMESTAMP=`date`
-else
-	TIMESTAMP=$KBUILD_BUILD_TIMESTAMP
-fi
 if test -z "$KBUILD_BUILD_USER"; then
 	LINUX_COMPILE_BY=$(whoami | sed 's/\\/\\\\/')
 else
@@ -39,63 +23,12 @@ else
 	LINUX_COMPILE_HOST=$KBUILD_BUILD_HOST
 fi
 
-UTS_VERSION="#$VERSION"
-CONFIG_FLAGS=""
-if [ -n "$SMP" ] ; then CONFIG_FLAGS="SMP"; fi
-
-if [ -n "$PREEMPT_RT" ] ; then
-	CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT_RT"
-elif [ -n "$PREEMPT_DYNAMIC" ] ; then
-	CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT_DYNAMIC"
-elif [ -n "$PREEMPT" ] ; then
-	CONFIG_FLAGS="$CONFIG_FLAGS PREEMPT"
-fi
-
-# Truncate to maximum length
-UTS_LEN=64
-UTS_VERSION="$(echo $UTS_VERSION $CONFIG_FLAGS $TIMESTAMP | cut -b -$UTS_LEN)"
-
-# Generate a temporary compile.h
-
-{ echo /\* This file is auto generated, version $VERSION \*/
-  if [ -n "$CONFIG_FLAGS" ] ; then echo "/* $CONFIG_FLAGS */"; fi
+LD_VERSION=$($LD -v | head -n1 | sed 's/(compatible with [^)]*)//' \
+	      | sed 's/[[:space:]]*$//')
 
-  echo \#define UTS_MACHINE \"$ARCH\"
-
-  echo \#define UTS_VERSION \"$UTS_VERSION\"
-
-  printf '#define LINUX_COMPILE_BY "%s"\n' "$LINUX_COMPILE_BY"
-  echo \#define LINUX_COMPILE_HOST \"$LINUX_COMPILE_HOST\"
-
-  LD_VERSION=$($LD -v | head -n1 | sed 's/(compatible with [^)]*)//' \
-		      | sed 's/[[:space:]]*$//')
-  printf '#define LINUX_COMPILER "%s"\n' "$CC_VERSION, $LD_VERSION"
-} > .tmpcompile
-
-# Only replace the real compile.h if the new one is different,
-# in order to preserve the timestamp and avoid unnecessary
-# recompilations.
-# We don't consider the file changed if only the date/time changed,
-# unless KBUILD_BUILD_TIMESTAMP was explicitly set (e.g. for
-# reproducible builds with that value referring to a commit timestamp).
-# A kernel config change will increase the generation number, thus
-# causing compile.h to be updated (including date/time) due to the
-# changed comment in the
-# first line.
-
-if [ -z "$KBUILD_BUILD_TIMESTAMP" ]; then
-   IGNORE_PATTERN="UTS_VERSION"
-else
-   IGNORE_PATTERN="NOT_A_PATTERN_TO_BE_MATCHED"
-fi
-
-if [ -r $TARGET ] && \
-      grep -v $IGNORE_PATTERN $TARGET > .tmpver.1 && \
-      grep -v $IGNORE_PATTERN .tmpcompile > .tmpver.2 && \
-      cmp -s .tmpver.1 .tmpver.2; then
-   rm -f .tmpcompile
-else
-   echo "  UPD     $TARGET"
-   mv -f .tmpcompile $TARGET
-fi
-rm -f .tmpver.1 .tmpver.2
+cat <<EOF
+#define UTS_MACHINE		"${UTS_MACHINE}"
+#define LINUX_COMPILE_BY	"${LINUX_COMPILE_BY}"
+#define LINUX_COMPILE_HOST	"${LINUX_COMPILE_HOST}"
+#define LINUX_COMPILER		"${CC_VERSION}, ${LD_VERSION}"
+EOF
-- 
2.34.1

[PATCH 06/15] kbuild: generate include/generated/compile.h in top Makefile

[Masahiro Yamada]

Now that UTS_VERSION was separated out, this header can be generated
much earlier, and probably the top Makefile is a better place to do it
than init/Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 Makefile      | 8 +++++++-
 init/Makefile | 8 +-------
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/Makefile b/Makefile
index 54e481162608..d933c0acab12 100644
--- a/Makefile
+++ b/Makefile
@@ -1198,7 +1198,7 @@ PHONY += prepare archprepare
 
 archprepare: outputmakefile archheaders archscripts scripts include/config/kernel.release \
 	asm-generic $(version_h) $(autoksyms_h) include/generated/utsrelease.h \
-	include/generated/autoconf.h remove-stale-files
+	include/generated/compile.h include/generated/autoconf.h remove-stale-files
 
 prepare0: archprepare
 	$(Q)$(MAKE) $(build)=scripts/mod
@@ -1260,6 +1260,12 @@ $(version_h): FORCE
 include/generated/utsrelease.h: include/config/kernel.release FORCE
 	$(call filechk,utsrelease.h)
 
+filechk_compile.h = $(srctree)/scripts/mkcompile_h \
+	"$(UTS_MACHINE)" "$(CONFIG_CC_VERSION_TEXT)" "$(LD)"
+
+include/generated/compile.h: FORCE
+	$(call filechk,compile.h)
+
 PHONY += headerdep
 headerdep:
 	$(Q)find $(srctree)/include/ -name '*.h' | xargs --max-args 1 \
diff --git a/init/Makefile b/init/Makefile
index 63f53d210cad..31c17a8e314b 100644
--- a/init/Makefile
+++ b/init/Makefile
@@ -43,15 +43,9 @@ filechk_uts_version = \
 $(obj)/utsversion-tmp.h: FORCE
 	$(call filechk,uts_version)
 
-$(obj)/version.o: include/generated/compile.h $(obj)/utsversion-tmp.h
+$(obj)/version.o: $(obj)/utsversion-tmp.h
 CFLAGS_version.o := -include $(obj)/utsversion-tmp.h
 
-filechk_compile.h = $(srctree)/scripts/mkcompile_h \
-	"$(UTS_MACHINE)" "$(CONFIG_CC_VERSION_TEXT)" "$(LD)"
-
-include/generated/compile.h: FORCE
-	$(call filechk,compile.h)
-
 #
 # Build version-timestamp.c with final UTS_VERSION
 #
-- 
2.34.1

[PATCH 07/15] scripts/mkcompile_h: move LC_ALL=C to '$LD -v'

[Masahiro Yamada]

Minimize the scope of LC_ALL=C like before commit 87c94bfb8ad3 ("kbuild:
override build timestamp & version").

Give LC_ALL=C to '$LD -v' to get the consistent version output, as commit
bcbcf50f5218 ("kbuild: fix ld-version.sh to not be affected by locale")
mentioned the LD version is affected by locale.

While I was here, I merged two sed invocations.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 scripts/mkcompile_h | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/scripts/mkcompile_h b/scripts/mkcompile_h
index f1a820d49e53..b76ccbbc094b 100755
--- a/scripts/mkcompile_h
+++ b/scripts/mkcompile_h
@@ -8,10 +8,6 @@ LD=$3
 # Do not expand names
 set -f
 
-# Fix the language to get consistent output
-LC_ALL=C
-export LC_ALL
-
 if test -z "$KBUILD_BUILD_USER"; then
 	LINUX_COMPILE_BY=$(whoami | sed 's/\\/\\\\/')
 else
@@ -23,8 +19,8 @@ else
 	LINUX_COMPILE_HOST=$KBUILD_BUILD_HOST
 fi
 
-LD_VERSION=$($LD -v | head -n1 | sed 's/(compatible with [^)]*)//' \
-	      | sed 's/[[:space:]]*$//')
+LD_VERSION=$(LC_ALL=C $LD -v | head -n1 |
+		sed -e 's/(compatible with [^)]*)//' -e 's/[[:space:]]*$//')
 
 cat <<EOF
 #define UTS_MACHINE		"${UTS_MACHINE}"
-- 
2.34.1

[PATCH 08/15] Revert "kbuild: Make scripts/compile.h when sh != bash"

[Masahiro Yamada]

This reverts commit [1] in the pre-git era.

I do not know what problem happened in the script when sh != bash
because there is no commit message.

Now that this script is much simpler than it used to be, let's revert
it, and let' see. (If this turns out to be problematic, fix the code
with proper commit description.)

[1]: https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=11acbbbb8a50f4de7dbe4bc1b5acc440dfe81810

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 scripts/mkcompile_h | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/scripts/mkcompile_h b/scripts/mkcompile_h
index b76ccbbc094b..2596f78e52ef 100755
--- a/scripts/mkcompile_h
+++ b/scripts/mkcompile_h
@@ -5,9 +5,6 @@ UTS_MACHINE=$1
 CC_VERSION="$2"
 LD=$3
 
-# Do not expand names
-set -f
-
 if test -z "$KBUILD_BUILD_USER"; then
 	LINUX_COMPILE_BY=$(whoami | sed 's/\\/\\\\/')
 else
-- 
2.34.1

[PATCH 09/15] kbuild: rename modules.order in sub-directories to .modules.order

[Masahiro Yamada]

The next commit will move core-y from the top Makefile to ./Kbuild to
use obj-y to list sub-directories.

With that, both ./Makefile and ./Kbuild would create modules.order in
the top directory.

To avoid the conflict, rename the per-directory modules.order to
.modules.order.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 Makefile               | 27 +++++++++++++--------------
 scripts/Makefile.build | 18 +++++++++---------
 scripts/Makefile.lib   |  8 ++++----
 3 files changed, 26 insertions(+), 27 deletions(-)

diff --git a/Makefile b/Makefile
index d933c0acab12..89aba2c69be8 100644
--- a/Makefile
+++ b/Makefile
@@ -1116,8 +1116,6 @@ vmlinux-alldirs	:= $(sort $(vmlinux-dirs) Documentation . \
 build-dirs	:= $(vmlinux-dirs)
 clean-dirs	:= $(vmlinux-alldirs)
 
-subdir-modorder := $(addsuffix /modules.order, $(build-dirs))
-
 # Externally visible symbols (used by link-vmlinux.sh)
 KBUILD_VMLINUX_OBJS := $(head-y) $(patsubst %/,%/built-in.a, $(core-y))
 KBUILD_VMLINUX_OBJS += $(addsuffix built-in.a, $(filter %/, $(libs-y)))
@@ -1172,7 +1170,7 @@ targets := vmlinux
 
 # The actual objects are generated when descending,
 # make sure no implicit rule kicks in
-$(sort $(vmlinux-deps) $(subdir-modorder)): descend ;
+$(sort $(vmlinux-deps)): descend ;
 
 filechk_kernel.release = \
 	echo "$(KERNELVERSION)$$($(CONFIG_SHELL) $(srctree)/scripts/setlocalversion $(srctree))"
@@ -1444,13 +1442,6 @@ endif
 
 modules: $(if $(KBUILD_BUILTIN),vmlinux) modules_prepare
 
-cmd_modules_order = cat $(real-prereqs) > $@
-
-modules.order: $(subdir-modorder) FORCE
-	$(call if_changed,modules_order)
-
-targets += modules.order
-
 # Target to prepare building external modules
 modules_prepare: prepare
 	$(Q)$(MAKE) $(build)=scripts scripts/module.lds
@@ -1722,8 +1713,6 @@ KBUILD_BUILTIN :=
 KBUILD_MODULES := 1
 
 build-dirs := $(KBUILD_EXTMOD)
-$(MODORDER): descend
-	@:
 
 compile_commands.json: $(extmod_prefix)compile_commands.json
 PHONY += compile_commands.json
@@ -1755,12 +1744,22 @@ help:
 endif # KBUILD_EXTMOD
 
 # ---------------------------------------------------------------------------
-# Modules
+# Modules (common for in-tree modules and external modules)
 
 PHONY += modules modules_install modules_prepare
 
 ifdef CONFIG_MODULES
 
+subdir-modorder := $(addsuffix /.modules.order, $(build-dirs))
+
+$(sort $(subdir-modorder)): %/.modules.order: % ;
+
+cmd_modules_order = cat $(real-prereqs) > $@
+
+targets += $(MODORDER)
+$(MODORDER): $(subdir-modorder) FORCE
+	$(call if_changed,modules_order)
+
 modules: modules_check
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
 
@@ -1860,7 +1859,7 @@ clean: $(clean-dirs)
 		-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
 		-o -name '*.lex.c' -o -name '*.tab.[ch]' \
 		-o -name '*.asn1.[ch]' \
-		-o -name '*.symtypes' -o -name 'modules.order' \
+		-o -name '*.symtypes' -o -name '*modules.order' \
 		-o -name '.tmp_*' \
 		-o -name '*.c.[012]*.*' \
 		-o -name '*.ll' \
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 0df488d0bbb0..c96c3c0ab228 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -73,7 +73,7 @@ endif
 
 # subdir-builtin and subdir-modorder may contain duplications. Use $(sort ...)
 subdir-builtin := $(sort $(filter %/built-in.a, $(real-obj-y)))
-subdir-modorder := $(sort $(filter %/modules.order, $(obj-m)))
+subdir-modorder := $(sort $(filter %/.modules.order, $(obj-m)))
 
 targets-for-builtin := $(extra-y)
 
@@ -89,7 +89,7 @@ targets-for-modules := $(foreach x, o mod $(if $(CONFIG_TRIM_UNUSED_KSYMS), usym
 				$(patsubst %.o, %.$x, $(filter %.o, $(obj-m))))
 
 ifdef need-modorder
-targets-for-modules += $(obj)/modules.order
+targets-for-modules += $(obj)/.modules.order
 endif
 
 targets += $(targets-for-builtin) $(targets-for-modules)
@@ -348,7 +348,7 @@ $(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
 
 # To build objects in subdirs, we need to descend into the directories
 $(subdir-builtin): $(obj)/%/built-in.a: $(obj)/% ;
-$(subdir-modorder): $(obj)/%/modules.order: $(obj)/% ;
+$(subdir-modorder): $(obj)/%/.modules.order: $(obj)/% ;
 
 #
 # Rule to compile a set of .o files into one .a file (without symbol table)
@@ -365,18 +365,18 @@ $(obj)/built-in.a: $(real-obj-y) FORCE
 	$(call if_changed,ar_builtin)
 
 #
-# Rule to create modules.order file
+# Rule to create .modules.order file
 #
-# Create commands to either record .ko file or cat modules.order from
+# Create commands to either record .ko file or cat .modules.order from
 # a subdirectory
 # Add $(obj-m) as the prerequisite to avoid updating the timestamp of
-# modules.order unless contained modules are updated.
+# .modules.order unless contained modules are updated.
 
 cmd_modules_order = { $(foreach m, $(real-prereqs), \
-	$(if $(filter %/modules.order, $m), cat $m, echo $(patsubst %.o,%.ko,$m));) :; } \
+	$(if $(filter %/.modules.order, $m), cat $m, echo $(patsubst %.o,%.ko,$m));) :; } \
 	> $@
 
-$(obj)/modules.order: $(obj-m) FORCE
+$(obj)/.modules.order: $(obj-m) FORCE
 	$(call if_changed,modules_order)
 
 #
@@ -465,7 +465,7 @@ $(subdir-ym):
 	$(Q)$(MAKE) $(build)=$@ \
 	$(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \
 	need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \
-	need-modorder=$(if $(filter $@/modules.order, $(subdir-modorder)),1)
+	need-modorder=$(if $(filter $@/.modules.order, $(subdir-modorder)),1)
 
 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
 # ---------------------------------------------------------------------------
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 3fb6a99e78c4..b594705d571a 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -26,14 +26,14 @@ subdir-ym := $(sort $(subdir-y) $(subdir-m) \
 
 # Handle objects in subdirs:
 # - If we encounter foo/ in $(obj-y), replace it by foo/built-in.a and
-#   foo/modules.order
-# - If we encounter foo/ in $(obj-m), replace it by foo/modules.order
+#   foo/.modules.order
+# - If we encounter foo/ in $(obj-m), replace it by foo/.modules.order
 #
-# Generate modules.order to determine modorder. Unfortunately, we don't have
+# Generate .modules.order to determine modorder. Unfortunately, we don't have
 # information about ordering between -y and -m subdirs. Just put -y's first.
 
 ifdef need-modorder
-obj-m := $(patsubst %/,%/modules.order, $(filter %/, $(obj-y)) $(obj-m))
+obj-m := $(patsubst %/,%/.modules.order, $(filter %/, $(obj-y)) $(obj-m))
 else
 obj-m := $(filter-out %/, $(obj-m))
 endif
-- 
2.34.1

[PATCH 10/15] kbuild: move core-y in top Makefile to ./Kbuild

[Masahiro Yamada]

Use the ordinary obj-y to list subdirectories.

There are some core-y entries remaining in arch/*/Makefile.
They will be moved after io_uring/built-in.a.

Note:
GNU Make seems to transform './.modules.order' to '.modules.order'
before matching it against the target pattern. Split ./.modules.order
to a dedicated rule to avoid "doesn't match the target pattern"
warning. [1]

[1]: https://lists.gnu.org/archive/html/bug-make/2022-08/msg00059.html

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 Kbuild                 | 16 ++++++++++++++++
 Makefile               | 10 +++++-----
 scripts/Makefile.build |  4 ++--
 3 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/Kbuild b/Kbuild
index 0b9e8a16a621..c8661cfc49a3 100644
--- a/Kbuild
+++ b/Kbuild
@@ -72,3 +72,19 @@ $(atomic-checks): $(obj)/.checked-%: include/linux/atomic/%  FORCE
 PHONY += prepare
 prepare: $(offsets-file) missing-syscalls $(atomic-checks)
 	@:
+
+# Ordinary directory descending
+# ---------------------------------------------------------------------------
+
+obj-y			+= init/
+obj-y			+= usr/
+obj-y			+= arch/$(SRCARCH)/
+obj-y			+= kernel/
+obj-y			+= certs/
+obj-y			+= mm/
+obj-y			+= fs/
+obj-y			+= ipc/
+obj-y			+= security/
+obj-y			+= crypto/
+obj-$(CONFIG_BLOCK)	+= block/
+obj-$(CONFIG_IO_URING)	+= io_uring/
diff --git a/Makefile b/Makefile
index 89aba2c69be8..1bc44bb4be1f 100644
--- a/Makefile
+++ b/Makefile
@@ -676,7 +676,7 @@ endif
 
 ifeq ($(KBUILD_EXTMOD),)
 # Objects we will link into vmlinux / subdirs we need to visit
-core-y		:= init/ usr/ arch/$(SRCARCH)/
+core-y		:= ./
 drivers-y	:= drivers/ sound/
 drivers-$(CONFIG_SAMPLES) += samples/
 drivers-$(CONFIG_NET) += net/
@@ -1101,9 +1101,6 @@ export MODORDER := $(extmod_prefix)modules.order
 export MODULES_NSDEPS := $(extmod_prefix)modules.nsdeps
 
 ifeq ($(KBUILD_EXTMOD),)
-core-y			+= kernel/ certs/ mm/ fs/ ipc/ security/ crypto/
-core-$(CONFIG_BLOCK)	+= block/
-core-$(CONFIG_IO_URING)	+= io_uring/
 
 vmlinux-dirs	:= $(patsubst %/,%,$(filter %/, \
 		     $(core-y) $(core-m) $(drivers-y) $(drivers-m) \
@@ -1752,7 +1749,10 @@ ifdef CONFIG_MODULES
 
 subdir-modorder := $(addsuffix /.modules.order, $(build-dirs))
 
-$(sort $(subdir-modorder)): %/.modules.order: % ;
+# Split ./.modules.order into a dedicate target to avoid
+# "doesn't match the target pattern" warning
+./.modules.order: . ;
+$(sort $(filter-out ./.modules.order, $(subdir-modorder))): %/.modules.order: % ;
 
 cmd_modules_order = cat $(real-prereqs) > $@
 
diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index c96c3c0ab228..098c811667d3 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -464,8 +464,8 @@ PHONY += $(subdir-ym)
 $(subdir-ym):
 	$(Q)$(MAKE) $(build)=$@ \
 	$(if $(filter $@/, $(KBUILD_SINGLE_TARGETS)),single-build=) \
-	need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin)),1) \
-	need-modorder=$(if $(filter $@/.modules.order, $(subdir-modorder)),1)
+	need-builtin=$(if $(filter $@/built-in.a, $(subdir-builtin:./%=%)),1) \
+	need-modorder=$(if $(filter $@/.modules.order, $(subdir-modorder:./%=%)),1)
 
 # Add FORCE to the prequisites of a target to force it to be always rebuilt.
 # ---------------------------------------------------------------------------
-- 
2.34.1

[PATCH 11/15] kbuild: move .vmlinux.objs rule to Makefile.modpost

[Masahiro Yamada]

.vmlinux.objs is used by modpost, so scripts/Makefile.modpost is
a better place to generate it.

It is used only when CONFIG_MODVERSIONS=y. It should be guarded
by "ifdef CONFIG_MODVERSIONS".

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 Makefile                 |  2 +-
 scripts/Makefile.modpost | 30 ++++++++++++++++++++++++++++--
 scripts/link-vmlinux.sh  | 18 ------------------
 3 files changed, 29 insertions(+), 21 deletions(-)

diff --git a/Makefile b/Makefile
index 1bc44bb4be1f..02724bcf8fdc 100644
--- a/Makefile
+++ b/Makefile
@@ -1489,7 +1489,7 @@ endif # CONFIG_MODULES
 # Directories & files removed with 'make clean'
 CLEAN_FILES += include/ksym vmlinux.symvers modules-only.symvers \
 	       modules.builtin modules.builtin.modinfo modules.nsdeps \
-	       compile_commands.json .thinlto-cache
+	       compile_commands.json .thinlto-cache .vmlinux.objs
 
 # Directories & files removed with 'make mrproper'
 MRPROPER_FILES += include/config include/generated          \
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 911606496341..04ad00917b2f 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -57,6 +57,32 @@ vmlinux.symvers: vmlinux.o
 
 __modpost: vmlinux.symvers
 
+# Generate the list of in-tree objects in vmlinux
+# ---------------------------------------------------------------------------
+
+# This is used to retrieve symbol versions generated by genksyms.
+ifdef CONFIG_MODVERSIONS
+vmlinux.symvers: .vmlinux.objs
+endif
+
+# Ignore libgcc.a
+# Some architectures do '$(CC) --print-libgcc-file-name' to borrow libgcc.a
+# from the toolchain, but there is no EXPORT_SYMBOL in it.
+
+quiet_cmd_vmlinux_objs = GEN     $@
+      cmd_vmlinux_objs =		\
+	for f in $(real-prereqs); do	\
+		case $${f} in		\
+		*libgcc.a) ;;		\
+		*.a) $(AR) t $${f} ;;	\
+		*) echo $${f} ;;	\
+		esac			\
+	done > $@
+
+targets += .vmlinux.objs
+.vmlinux.objs: $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
+	$(call if_changed,vmlinux_objs)
+
 else
 
 ifeq ($(KBUILD_EXTMOD),)
@@ -134,6 +160,8 @@ ifneq ($(KBUILD_MODPOST_NOFINAL),1)
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
 endif
 
+endif
+
 PHONY += FORCE
 FORCE:
 
@@ -141,6 +169,4 @@ existing-targets := $(wildcard $(sort $(targets)))
 
 -include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
 
-endif
-
 .PHONY: $(PHONY)
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 8d982574145a..161bca64e8aa 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -199,7 +199,6 @@ cleanup()
 	rm -f System.map
 	rm -f vmlinux
 	rm -f vmlinux.map
-	rm -f .vmlinux.objs
 	rm -f .vmlinux.export.c
 }
 
@@ -218,23 +217,6 @@ fi
 #link vmlinux.o
 ${MAKE} -f "${srctree}/scripts/Makefile.vmlinux_o"
 
-# Generate the list of in-tree objects in vmlinux
-#
-# This is used to retrieve symbol versions generated by genksyms.
-for f in ${KBUILD_VMLINUX_OBJS} ${KBUILD_VMLINUX_LIBS}; do
-	case ${f} in
-	*libgcc.a)
-		# Some architectures do '$(CC) --print-libgcc-file-name' to
-		# borrow libgcc.a from the toolchain.
-		# There is no EXPORT_SYMBOL in external objects. Ignore this.
-		;;
-	*.a)
-		${AR} t ${f} ;;
-	*)
-		echo ${f} ;;
-	esac
-done > .vmlinux.objs
-
 # modpost vmlinux.o to check for section mismatches
 ${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1
 
-- 
2.34.1

[PATCH 12/15] kbuild: move vmlinux.o rule to the top Makefile

[Masahiro Yamada]

Move the build rules of vmlinux.o out of scripts/link-vmlinux.sh to
clearly separate 1) pre-modpost, 2) modpost, 3) post-modpost stages.
This will make furture refactoring possible.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 Makefile                | 10 ++++++++--
 scripts/link-vmlinux.sh |  3 ---
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index 02724bcf8fdc..d81b7a587b43 100644
--- a/Makefile
+++ b/Makefile
@@ -645,6 +645,8 @@ else
 __all: modules
 endif
 
+targets :=
+
 # Decide whether to build built-in, modular, or both.
 # Normally, just do built-in.
 
@@ -1153,6 +1155,10 @@ quiet_cmd_autoksyms_h = GEN     $@
 $(autoksyms_h):
 	$(call cmd,autoksyms_h)
 
+targets += vmlinux.o
+vmlinux.o: autoksyms_recursive $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
+	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.vmlinux_o
+
 ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
 
 # Final link of vmlinux with optional arch pass after final link
@@ -1160,10 +1166,10 @@ cmd_link-vmlinux =                                                 \
 	$(CONFIG_SHELL) $< "$(LD)" "$(KBUILD_LDFLAGS)" "$(LDFLAGS_vmlinux)";    \
 	$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
 
-vmlinux: scripts/link-vmlinux.sh autoksyms_recursive $(vmlinux-deps) FORCE
+vmlinux: scripts/link-vmlinux.sh vmlinux.o $(KBUILD_LDS) FORCE
 	+$(call if_changed_dep,link-vmlinux)
 
-targets := vmlinux
+targets += vmlinux
 
 # The actual objects are generated when descending,
 # make sure no implicit rule kicks in
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 161bca64e8aa..07486f90d5e2 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -214,9 +214,6 @@ if [ "$1" = "clean" ]; then
 	exit 0
 fi
 
-#link vmlinux.o
-${MAKE} -f "${srctree}/scripts/Makefile.vmlinux_o"
-
 # modpost vmlinux.o to check for section mismatches
 ${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1
 
-- 
2.34.1

[PATCH 13/15] kbuild: unify two modpost invocations

[Masahiro Yamada]

Currently, modpost is executed twice; first for vmlinux, second
for modules.

This commit unfies them.

Current build flow
==================

  1) build obj-y and obj-m objects
    2) link vmlinux.o
      3) modpost for vmlinux
        4) link vmlinux
          5) modpost for modules
            6) link modules (*.ko)

The build steps 1) through 6) are serialized (that is, modules are
built after vmlinux). We do not get benefits of parallel builds
when scripts/link-vmlinux.sh is being run.

New build flow
==============

  1) build obj-y and obj-m objects
    2) link vmlinux.o
      3) modpost for vmlinux and modules
        4a) link vmlinux
        4b) link modules (*.ko)

In the new build flow, modpost is invoked just once.

vmlinux and modules are built in parallel. One exception is
CONFIG_DEBUG_INFO_BTF_MODULES=y, where modules depend on vmlinux.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 Makefile                  | 30 ++++++++++---
 scripts/Makefile.modfinal |  2 +-
 scripts/Makefile.modpost  | 93 ++++++++++++---------------------------
 scripts/link-vmlinux.sh   |  3 --
 4 files changed, 53 insertions(+), 75 deletions(-)

diff --git a/Makefile b/Makefile
index d81b7a587b43..292b6e90da20 100644
--- a/Makefile
+++ b/Makefile
@@ -1166,7 +1166,7 @@ cmd_link-vmlinux =                                                 \
 	$(CONFIG_SHELL) $< "$(LD)" "$(KBUILD_LDFLAGS)" "$(LDFLAGS_vmlinux)";    \
 	$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
 
-vmlinux: scripts/link-vmlinux.sh vmlinux.o $(KBUILD_LDS) FORCE
+vmlinux: scripts/link-vmlinux.sh vmlinux.o $(KBUILD_LDS) modpost FORCE
 	+$(call if_changed_dep,link-vmlinux)
 
 targets += vmlinux
@@ -1443,7 +1443,13 @@ endif
 # Build modules
 #
 
-modules: $(if $(KBUILD_BUILTIN),vmlinux) modules_prepare
+# *.ko are usually independent of vmlinux, but CONFIG_DEBUG_INFOBTF_MODULES
+# is an exception.
+ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+modules: vmlinux
+endif
+
+modules: modules_prepare
 
 # Target to prepare building external modules
 modules_prepare: prepare
@@ -1766,8 +1772,12 @@ targets += $(MODORDER)
 $(MODORDER): $(subdir-modorder) FORCE
 	$(call if_changed,modules_order)
 
-modules: modules_check
-	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
+# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
+# This is solely useful to speed up test compiles.
+modules: modpost
+ifneq ($(KBUILD_MODPOST_NOFINAL),1)
+	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
+endif
 
 PHONY += modules_check
 modules_check: $(MODORDER)
@@ -1798,6 +1808,11 @@ KBUILD_MODULES :=
 
 endif # CONFIG_MODULES
 
+PHONY += modpost
+modpost: $(if $(single-build),, $(if $(KBUILD_BUILTIN), vmlinux.o)) \
+	 $(if $(KBUILD_MODULES), modules_check)
+	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
+
 # Single targets
 # ---------------------------------------------------------------------------
 # To build individual files in subdirectories, you can do like this:
@@ -1817,16 +1832,19 @@ single-ko := $(sort $(filter %.ko, $(MAKECMDGOALS)))
 single-no-ko := $(filter-out $(single-ko), $(MAKECMDGOALS)) \
 		$(foreach x, o mod, $(patsubst %.ko, %.$x, $(single-ko)))
 
-$(single-ko): single_modpost
+$(single-ko): single_modules
 	@:
 $(single-no-ko): descend
 	@:
 
 # Remove MODORDER when done because it is not the real one.
 PHONY += single_modpost
-single_modpost: $(single-no-ko) modules_prepare
+single_modules: $(single-no-ko) modules_prepare
 	$(Q){ $(foreach m, $(single-ko), echo $(extmod_prefix)$m;) } > $(MODORDER)
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
+ifneq ($(KBUILD_MODPOST_NOFINAL),1)
+	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
+endif
 	$(Q)rm -f $(MODORDER)
 
 export KBUILD_SINGLE_TARGETS := $(addprefix $(extmod_prefix), $(single-no-ko))
diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
index 35100e981f4a..a3cf9e3647c9 100644
--- a/scripts/Makefile.modfinal
+++ b/scripts/Makefile.modfinal
@@ -55,7 +55,7 @@ if_changed_except = $(if $(call newer_prereqs_except,$(2))$(cmd-check),      \
 	printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
 
 # Re-generate module BTFs if either module's .ko or vmlinux changed
-$(modules): %.ko: %.o %.mod.o scripts/module.lds $(if $(KBUILD_BUILTIN),vmlinux) FORCE
+$(modules): %.ko: %.o %.mod.o scripts/module.lds $(and $(CONFIG_DEBUG_INFO_BTF_MODULES),$(KBUILD_BUILTIN),vmlinux) FORCE
 	+$(call if_changed_except,ld_ko_o,vmlinux)
 ifdef CONFIG_DEBUG_INFO_BTF_MODULES
 	+$(if $(newer-prereqs),$(call cmd,btf_ko))
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 04ad00917b2f..d7d3138c5ecc 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -32,9 +32,6 @@
 # Step 4 is solely used to allow module versioning in external modules,
 # where the CRC of each module is retrieved from the Module.symvers file.
 
-# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
-# This is solely useful to speed up test compiles
-
 PHONY := __modpost
 __modpost:
 
@@ -45,24 +42,23 @@ MODPOST = scripts/mod/modpost								\
 	$(if $(CONFIG_MODVERSIONS),-m)							\
 	$(if $(CONFIG_MODULE_SRCVERSION_ALL),-a)					\
 	$(if $(CONFIG_SECTION_MISMATCH_WARN_ONLY),,-E)					\
+	$(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS))					\
+	$(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N)	\
 	-o $@
 
-ifdef MODPOST_VMLINUX
-
-quiet_cmd_modpost = MODPOST $@
-      cmd_modpost = $(MODPOST) $<
-
-vmlinux.symvers: vmlinux.o
-	$(call cmd,modpost)
+# 'make -i -k' ignores compile errors, and builds as many modules as possible.
+ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
+MODPOST += -n
+endif
 
-__modpost: vmlinux.symvers
+ifeq ($(KBUILD_EXTMOD),)
 
 # Generate the list of in-tree objects in vmlinux
 # ---------------------------------------------------------------------------
 
 # This is used to retrieve symbol versions generated by genksyms.
 ifdef CONFIG_MODVERSIONS
-vmlinux.symvers: .vmlinux.objs
+vmlinux.symvers Module.symvers: .vmlinux.objs
 endif
 
 # Ignore libgcc.a
@@ -83,24 +79,12 @@ targets += .vmlinux.objs
 .vmlinux.objs: $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
 	$(call if_changed,vmlinux_objs)
 
-else
-
-ifeq ($(KBUILD_EXTMOD),)
-
-input-symdump := vmlinux.symvers
-output-symdump := modules-only.symvers
-
-quiet_cmd_cat = GEN     $@
-      cmd_cat = cat $(real-prereqs) > $@
-
-ifneq ($(wildcard vmlinux.symvers),)
-
-__modpost: Module.symvers
-Module.symvers: vmlinux.symvers modules-only.symvers FORCE
-	$(call if_changed,cat)
-
-targets += Module.symvers
+vmlinux.o-if-present := $(wildcard vmlinux.o)
+output-symdump := vmlinux.symvers
 
+ifdef KBUILD_MODULES
+output-symdump := $(if $(vmlinux.o-if-present), Module.symvers, modules-only.symvers)
+missing-input := $(filter-out $(vmlinux.o-if-present),vmlinux.o)
 endif
 
 else
@@ -112,56 +96,35 @@ src := $(obj)
 # Include the module's Makefile to find KBUILD_EXTRA_SYMBOLS
 include $(or $(wildcard $(src)/Kbuild), $(src)/Makefile)
 
-# modpost option for external modules
-MODPOST += -e
-
-input-symdump := Module.symvers $(KBUILD_EXTRA_SYMBOLS)
+module.symvers-if-present := $(wildcard Module.symvers)
 output-symdump := $(KBUILD_EXTMOD)/Module.symvers
+missing-input := $(filter-out $(module.symvers-if-present), Module.symvers)
 
-endif
-
-existing-input-symdump := $(wildcard $(input-symdump))
-
-# modpost options for modules (both in-kernel and external)
-MODPOST += \
-	$(addprefix -i ,$(existing-input-symdump)) \
-	$(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS)) \
-	$(if $(CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS)$(KBUILD_NSDEPS),-N)
-
-# 'make -i -k' ignores compile errors, and builds as many modules as possible.
-ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
-MODPOST += -n
-endif
+MODPOST += -e $(addprefix -i ,$(module.symvers-if-present) (KBUILD_EXTRA_SYMBOLS))
 
-# Clear VPATH to not search for *.symvers in $(srctree). Check only $(objtree).
-VPATH :=
-$(input-symdump):
-	@echo >&2 'WARNING: Symbol version dump "$@" is missing.'
-	@echo >&2 '         Modules may not have dependencies or modversions.'
-	@echo >&2 '         You may get many unresolved symbol warnings.'
+endif # ($(KBUILD_EXTMOD),)
 
-# KBUILD_MODPOST_WARN can be set to avoid error out in case of undefined symbols
-ifneq ($(KBUILD_MODPOST_WARN)$(filter-out $(existing-input-symdump), $(input-symdump)),)
+ifneq ($(KBUILD_MODPOST_WARN)$(missing-input),)
 MODPOST += -w
 endif
 
+modorder-if-needed := $(if $(KBUILD_MODULES), $(MODORDER))
+
 # Read out modules.order to pass in modpost.
 # Otherwise, allmodconfig would fail with "Argument list too long".
 quiet_cmd_modpost = MODPOST $@
-      cmd_modpost = sed 's/ko$$/o/' $< | $(MODPOST) -T -
-
-$(output-symdump): $(MODORDER) $(input-symdump) FORCE
-	$(call if_changed,modpost)
+      cmd_modpost = \
+	$(if $(missing-input), \
+		echo >&2 "WARNING: $(missing-input) is missing."; \
+		echo >&2 "         Modules may not have dependencies or modversions."; \
+		echo >&2 "         You may get many unresolved symbol warnings.";) \
+	sed 's/ko$$/o/' $(or $(modorder-if-needed), /dev/null) | $(MODPOST) $(vmlinux.o-if-present) -T -
 
 targets += $(output-symdump)
+$(output-symdump): $(modorder-if-needed) $(vmlinux.o-if-present) $(moudle.symvers-if-present) FORCE
+	$(call if_changed,modpost)
 
 __modpost: $(output-symdump)
-ifneq ($(KBUILD_MODPOST_NOFINAL),1)
-	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
-endif
-
-endif
-
 PHONY += FORCE
 FORCE:
 
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 07486f90d5e2..6a197d8a88ac 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -214,9 +214,6 @@ if [ "$1" = "clean" ]; then
 	exit 0
 fi
 
-# modpost vmlinux.o to check for section mismatches
-${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1
-
 info MODINFO modules.builtin.modinfo
 ${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo
 info GEN modules.builtin
-- 
2.34.1

[PATCH 14/15] kbuild: use obj-y instead extra-y for objects placed at the head

[Masahiro Yamada]

The objects placed at the head of vmlinux need special treatments:

 - arch/$(SRCARCH)/Makefile adds them to head-y in order to place
   them before other archives in the linker command line.

 - arch/$(SRCARCH)/kernel/Makefile adds them to extra-y instead of
   obj-y to avoid them going into built-in.a.

This commit gets rid of the second one.

Create vmlinux.a to collect all the objects that are unconditionally
linked to vmlinux. The objects listed in head-y are moved to the head
of vmlinux.a by using 'ar m'.

With this, arch/$(SRCARCH)/kernel/Makefile can consistently use obj-y
for builtin objects.

There is no *.o that is directly linked to vmlinux. Drop unneeded code
in scripts/clang-tools/gen_compile_commands.py.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 Documentation/kbuild/makefiles.rst          | 18 +----------------
 Makefile                                    | 18 +++++++++++++----
 arch/alpha/kernel/Makefile                  |  4 ++--
 arch/arc/kernel/Makefile                    |  4 ++--
 arch/arm/kernel/Makefile                    |  4 ++--
 arch/arm64/kernel/Makefile                  |  4 ++--
 arch/csky/kernel/Makefile                   |  4 ++--
 arch/hexagon/kernel/Makefile                |  3 ++-
 arch/ia64/kernel/Makefile                   |  4 ++--
 arch/loongarch/kernel/Makefile              |  4 ++--
 arch/m68k/68000/Makefile                    |  2 +-
 arch/m68k/coldfire/Makefile                 |  2 +-
 arch/m68k/kernel/Makefile                   | 21 ++++++++++----------
 arch/microblaze/kernel/Makefile             |  4 ++--
 arch/mips/kernel/Makefile                   |  4 ++--
 arch/nios2/kernel/Makefile                  |  2 +-
 arch/openrisc/kernel/Makefile               |  4 ++--
 arch/parisc/kernel/Makefile                 |  4 ++--
 arch/powerpc/kernel/Makefile                | 22 ++++++++++-----------
 arch/riscv/kernel/Makefile                  |  2 +-
 arch/s390/kernel/Makefile                   |  4 ++--
 arch/sh/kernel/Makefile                     |  4 ++--
 arch/sparc/kernel/Makefile                  |  3 +--
 arch/x86/kernel/Makefile                    | 10 +++++-----
 arch/xtensa/kernel/Makefile                 |  4 ++--
 scripts/Makefile.modpost                    |  5 ++---
 scripts/Makefile.vmlinux_o                  |  6 +++---
 scripts/clang-tools/gen_compile_commands.py | 19 +-----------------
 scripts/link-vmlinux.sh                     | 10 ++++------
 29 files changed, 87 insertions(+), 112 deletions(-)

diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
index 11a296e52d68..07c7e5a843c1 100644
--- a/Documentation/kbuild/makefiles.rst
+++ b/Documentation/kbuild/makefiles.rst
@@ -340,19 +340,7 @@ more details, with real examples.
 
 	Examples are:
 
-	1) head objects
-
-	    Some objects must be placed at the head of vmlinux. They are
-	    directly linked to vmlinux without going through built-in.a
-	    A typical use-case is an object that contains the entry point.
-
-	    arch/$(SRCARCH)/Makefile should specify such objects as head-y.
-
-	    Discussion:
-	      Given that we can control the section order in the linker script,
-	      why do we need head-y?
-
-	2) vmlinux linker script
+	1) vmlinux linker script
 
 	    The linker script for vmlinux is located at
 	    arch/$(SRCARCH)/kernel/vmlinux.lds
@@ -360,10 +348,6 @@ more details, with real examples.
 	Example::
 
 		# arch/x86/kernel/Makefile
-		extra-y	:= head_$(BITS).o
-		extra-y	+= head$(BITS).o
-		extra-y	+= ebda.o
-		extra-y	+= platform-quirks.o
 		extra-y	+= vmlinux.lds
 
 	$(extra-y) should only contain targets needed for vmlinux.
diff --git a/Makefile b/Makefile
index 292b6e90da20..d74aa4552d35 100644
--- a/Makefile
+++ b/Makefile
@@ -1116,7 +1116,7 @@ build-dirs	:= $(vmlinux-dirs)
 clean-dirs	:= $(vmlinux-alldirs)
 
 # Externally visible symbols (used by link-vmlinux.sh)
-KBUILD_VMLINUX_OBJS := $(head-y) $(patsubst %/,%/built-in.a, $(core-y))
+KBUILD_VMLINUX_OBJS := $(patsubst %/,%/built-in.a, $(core-y))
 KBUILD_VMLINUX_OBJS += $(addsuffix built-in.a, $(filter %/, $(libs-y)))
 ifdef CONFIG_MODULES
 KBUILD_VMLINUX_OBJS += $(patsubst %/, %/lib.a, $(filter %/, $(libs-y)))
@@ -1126,7 +1126,7 @@ KBUILD_VMLINUX_LIBS := $(patsubst %/,%/lib.a, $(libs-y))
 endif
 KBUILD_VMLINUX_OBJS += $(patsubst %/,%/built-in.a, $(drivers-y))
 
-export KBUILD_VMLINUX_OBJS KBUILD_VMLINUX_LIBS
+export KBUILD_VMLINUX_LIBS
 export KBUILD_LDS          := arch/$(SRCARCH)/kernel/vmlinux.lds
 # used by scripts/Makefile.package
 export KBUILD_ALLDIRS := $(sort $(filter-out arch/%,$(vmlinux-alldirs)) LICENSES arch include scripts tools)
@@ -1155,8 +1155,18 @@ quiet_cmd_autoksyms_h = GEN     $@
 $(autoksyms_h):
 	$(call cmd,autoksyms_h)
 
+quiet_cmd_ar_vmlinux.a = AR      $@
+      cmd_ar_vmlinux.a = \
+	rm -f $@; \
+	$(AR) cDPrST $@ $(KBUILD_VMLINUX_OBJS); \
+	$(AR) mPi $$($(AR) t $@| head -n1) $@ $(head-y)
+
+targets += vmlinux.a
+vmlinux.a: $(KBUILD_VMLINUX_OBJS) FORCE
+	$(call if_changed,ar_vmlinux.a)
+
 targets += vmlinux.o
-vmlinux.o: autoksyms_recursive $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
+vmlinux.o: autoksyms_recursive vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
 	$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.vmlinux_o
 
 ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
@@ -1913,7 +1923,7 @@ quiet_cmd_gen_compile_commands = GEN     $@
       cmd_gen_compile_commands = $(PYTHON3) $< -a $(AR) -o $@ $(filter-out $<, $(real-prereqs))
 
 $(extmod_prefix)compile_commands.json: scripts/clang-tools/gen_compile_commands.py \
-	$(if $(KBUILD_EXTMOD),,$(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)) \
+	$(if $(KBUILD_EXTMOD),, vmlinux.a $(KBUILD_VMLINUX_LIBS)) \
 	$(if $(CONFIG_MODULES), $(MODORDER)) FORCE
 	$(call if_changed,gen_compile_commands)
 
diff --git a/arch/alpha/kernel/Makefile b/arch/alpha/kernel/Makefile
index 5a74581bf0ee..5a5b0a8b7c6a 100644
--- a/arch/alpha/kernel/Makefile
+++ b/arch/alpha/kernel/Makefile
@@ -3,11 +3,11 @@
 # Makefile for the linux kernel.
 #
 
-extra-y		:= head.o vmlinux.lds
+extra-y		:= vmlinux.lds
 asflags-y	:= $(KBUILD_CFLAGS)
 ccflags-y	:= -Wno-sign-compare
 
-obj-y    := entry.o traps.o process.o osf_sys.o irq.o \
+obj-y    := head.o entry.o traps.o process.o osf_sys.o irq.o \
 	    irq_alpha.o signal.o setup.o ptrace.o time.o \
 	    systbls.o err_common.o io.o bugs.o
 
diff --git a/arch/arc/kernel/Makefile b/arch/arc/kernel/Makefile
index 8c4fc4b54c14..0723d888ac44 100644
--- a/arch/arc/kernel/Makefile
+++ b/arch/arc/kernel/Makefile
@@ -3,7 +3,7 @@
 # Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
 #
 
-obj-y	:= arcksyms.o setup.o irq.o reset.o ptrace.o process.o devtree.o
+obj-y	:= head.o arcksyms.o setup.o irq.o reset.o ptrace.o process.o devtree.o
 obj-y	+= signal.o traps.o sys.o troubleshoot.o stacktrace.o disasm.o
 obj-$(CONFIG_ISA_ARCOMPACT)		+= entry-compact.o intc-compact.o
 obj-$(CONFIG_ISA_ARCV2)			+= entry-arcv2.o intc-arcv2.o
@@ -31,4 +31,4 @@ else
 obj-y += ctx_sw_asm.o
 endif
 
-extra-y := vmlinux.lds head.o
+extra-y := vmlinux.lds
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index 553866751e1a..8feaa3217ec5 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -89,7 +89,7 @@ obj-$(CONFIG_VDSO)		+= vdso.o
 obj-$(CONFIG_EFI)		+= efi.o
 obj-$(CONFIG_PARAVIRT)	+= paravirt.o
 
-head-y			:= head$(MMUEXT).o
+obj-y			+= head$(MMUEXT).o
 obj-$(CONFIG_DEBUG_LL)	+= debug.o
 obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 obj-$(CONFIG_ARM_PATCH_PHYS_VIRT)	+= phys2virt.o
@@ -109,4 +109,4 @@ obj-$(CONFIG_HAVE_ARM_SMCCC)	+= smccc-call.o
 
 obj-$(CONFIG_GENERIC_CPU_VULNERABILITIES) += spectre.o
 
-extra-y := $(head-y) vmlinux.lds
+extra-y := vmlinux.lds
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 1add7b01efa7..b619ff207a57 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -85,8 +85,8 @@ $(obj)/vdso-wrap.o: $(obj)/vdso/vdso.so
 $(obj)/vdso32-wrap.o: $(obj)/vdso32/vdso.so
 
 obj-y					+= probes/
-head-y					:= head.o
-extra-y					+= $(head-y) vmlinux.lds
+obj-y					+= head.o
+extra-y					+= vmlinux.lds
 
 ifeq ($(CONFIG_DEBUG_EFI),y)
 AFLAGS_head.o += -DVMLINUX_PATH="\"$(realpath $(objtree)/vmlinux)\""
diff --git a/arch/csky/kernel/Makefile b/arch/csky/kernel/Makefile
index 6f14c924b20d..8a868316b912 100644
--- a/arch/csky/kernel/Makefile
+++ b/arch/csky/kernel/Makefile
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
-extra-y := head.o vmlinux.lds
+extra-y := vmlinux.lds
 
-obj-y += entry.o atomic.o signal.o traps.o irq.o time.o vdso.o vdso/
+obj-y += head.o entry.o atomic.o signal.o traps.o irq.o time.o vdso.o vdso/
 obj-y += power.o syscall.o syscall_table.o setup.o io.o
 obj-y += process.o cpu-probe.o ptrace.o stacktrace.o
 obj-y += probes/
diff --git a/arch/hexagon/kernel/Makefile b/arch/hexagon/kernel/Makefile
index fae3dce32fde..e73cb321630e 100644
--- a/arch/hexagon/kernel/Makefile
+++ b/arch/hexagon/kernel/Makefile
@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
-extra-y := head.o vmlinux.lds
+extra-y := vmlinux.lds
 
+obj-y += head.o
 obj-$(CONFIG_SMP) += smp.o
 
 obj-y += setup.o irq_cpu.o traps.o syscalltab.o signal.o time.o
diff --git a/arch/ia64/kernel/Makefile b/arch/ia64/kernel/Makefile
index 08d4a2ba0652..4a1fcb121dda 100644
--- a/arch/ia64/kernel/Makefile
+++ b/arch/ia64/kernel/Makefile
@@ -7,9 +7,9 @@ ifdef CONFIG_DYNAMIC_FTRACE
 CFLAGS_REMOVE_ftrace.o = -pg
 endif
 
-extra-y	:= head.o vmlinux.lds
+extra-y	:= vmlinux.lds
 
-obj-y := entry.o efi.o efi_stub.o gate-data.o fsys.o irq.o irq_ia64.o	\
+obj-y := head.o entry.o efi.o efi_stub.o gate-data.o fsys.o irq.o irq_ia64.o	\
 	 irq_lsapic.o ivt.o pal.o patch.o process.o ptrace.o sal.o		\
 	 salinfo.o setup.o signal.o sys_ia64.o time.o traps.o unaligned.o \
 	 unwind.o mca.o mca_asm.o topology.o dma-mapping.o iosapic.o acpi.o \
diff --git a/arch/loongarch/kernel/Makefile b/arch/loongarch/kernel/Makefile
index e5be17009fe8..6c33b5c45573 100644
--- a/arch/loongarch/kernel/Makefile
+++ b/arch/loongarch/kernel/Makefile
@@ -3,9 +3,9 @@
 # Makefile for the Linux/LoongArch kernel.
 #
 
-extra-y		:= head.o vmlinux.lds
+extra-y		:= vmlinux.lds
 
-obj-y		+= cpu-probe.o cacheinfo.o env.o setup.o entry.o genex.o \
+obj-y		+= head.o cpu-probe.o cacheinfo.o env.o setup.o entry.o genex.o \
 		   traps.o irq.o idle.o process.o dma.o mem.o io.o reset.o switch.o \
 		   elf.o syscall.o signal.o time.o topology.o inst.o ptrace.o vdso.o
 
diff --git a/arch/m68k/68000/Makefile b/arch/m68k/68000/Makefile
index 674541fdf5b8..279560add577 100644
--- a/arch/m68k/68000/Makefile
+++ b/arch/m68k/68000/Makefile
@@ -17,4 +17,4 @@ obj-$(CONFIG_DRAGEN2)	+= dragen2.o
 obj-$(CONFIG_UCSIMM)	+= ucsimm.o
 obj-$(CONFIG_UCDIMM)	+= ucsimm.o
 
-extra-y 		:= head.o
+obj-y			+= head.o
diff --git a/arch/m68k/coldfire/Makefile b/arch/m68k/coldfire/Makefile
index 9419a6c1f036..c56bc0dc7f2e 100644
--- a/arch/m68k/coldfire/Makefile
+++ b/arch/m68k/coldfire/Makefile
@@ -45,4 +45,4 @@ obj-$(CONFIG_STMARK2)	+= stmark2.o
 obj-$(CONFIG_PCI)	+= pci.o
 
 obj-y			+= gpio.o
-extra-y := head.o
+obj-y			+= head.o
diff --git a/arch/m68k/kernel/Makefile b/arch/m68k/kernel/Makefile
index c0833da6a2ca..1755e6cd309f 100644
--- a/arch/m68k/kernel/Makefile
+++ b/arch/m68k/kernel/Makefile
@@ -3,18 +3,19 @@
 # Makefile for the linux kernel.
 #
 
-extra-$(CONFIG_AMIGA)	:= head.o
-extra-$(CONFIG_ATARI)	:= head.o
-extra-$(CONFIG_MAC)	:= head.o
-extra-$(CONFIG_APOLLO)	:= head.o
-extra-$(CONFIG_VME)	:= head.o
-extra-$(CONFIG_HP300)	:= head.o
-extra-$(CONFIG_Q40)	:= head.o
-extra-$(CONFIG_SUN3X)	:= head.o
-extra-$(CONFIG_VIRT)	:= head.o
-extra-$(CONFIG_SUN3)	:= sun3-head.o
 extra-y			+= vmlinux.lds
 
+obj-$(CONFIG_AMIGA)	:= head.o
+obj-$(CONFIG_ATARI)	:= head.o
+obj-$(CONFIG_MAC)	:= head.o
+obj-$(CONFIG_APOLLO)	:= head.o
+obj-$(CONFIG_VME)	:= head.o
+obj-$(CONFIG_HP300)	:= head.o
+obj-$(CONFIG_Q40)	:= head.o
+obj-$(CONFIG_SUN3X)	:= head.o
+obj-$(CONFIG_VIRT)	:= head.o
+obj-$(CONFIG_SUN3)	:= sun3-head.o
+
 obj-y	:= entry.o irq.o module.o process.o ptrace.o
 obj-y	+= setup.o signal.o sys_m68k.o syscalltable.o time.o traps.o
 
diff --git a/arch/microblaze/kernel/Makefile b/arch/microblaze/kernel/Makefile
index 15a20eb814ce..4393bee64eaf 100644
--- a/arch/microblaze/kernel/Makefile
+++ b/arch/microblaze/kernel/Makefile
@@ -12,9 +12,9 @@ CFLAGS_REMOVE_ftrace.o = -pg
 CFLAGS_REMOVE_process.o = -pg
 endif
 
-extra-y := head.o vmlinux.lds
+extra-y := vmlinux.lds
 
-obj-y += dma.o exceptions.o \
+obj-y += head.o dma.o exceptions.o \
 	hw_exception_handler.o irq.o \
 	process.o prom.o ptrace.o \
 	reset.o setup.o signal.o sys_microblaze.o timer.o traps.o unwind.o
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 7c96282bff2e..5d1addac5e28 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -3,9 +3,9 @@
 # Makefile for the Linux/MIPS kernel.
 #
 
-extra-y		:= head.o vmlinux.lds
+extra-y		:= vmlinux.lds
 
-obj-y		+= branch.o cmpxchg.o elf.o entry.o genex.o idle.o irq.o \
+obj-y		+= head.o branch.o cmpxchg.o elf.o entry.o genex.o idle.o irq.o \
 		   process.o prom.o ptrace.o reset.o setup.o signal.o \
 		   syscall.o time.o topology.o traps.o unaligned.o watch.o \
 		   vdso.o cacheinfo.o
diff --git a/arch/nios2/kernel/Makefile b/arch/nios2/kernel/Makefile
index 0b645e1e3158..78a913181fa1 100644
--- a/arch/nios2/kernel/Makefile
+++ b/arch/nios2/kernel/Makefile
@@ -3,9 +3,9 @@
 # Makefile for the nios2 linux kernel.
 #
 
-extra-y	+= head.o
 extra-y	+= vmlinux.lds
 
+obj-y	+= head.o
 obj-y	+= cpuinfo.o
 obj-y	+= entry.o
 obj-y	+= insnemu.o
diff --git a/arch/openrisc/kernel/Makefile b/arch/openrisc/kernel/Makefile
index 2d172e79f58d..79129161f3e0 100644
--- a/arch/openrisc/kernel/Makefile
+++ b/arch/openrisc/kernel/Makefile
@@ -3,9 +3,9 @@
 # Makefile for the linux kernel.
 #
 
-extra-y	:= head.o vmlinux.lds
+extra-y	:= vmlinux.lds
 
-obj-y	:= setup.o or32_ksyms.o process.o dma.o \
+obj-y	:= head.o setup.o or32_ksyms.o process.o dma.o \
 	   traps.o time.o irq.o entry.o ptrace.o signal.o \
 	   sys_call_table.o unwinder.o
 
diff --git a/arch/parisc/kernel/Makefile b/arch/parisc/kernel/Makefile
index d0bfac89a842..3d138c9cf9ce 100644
--- a/arch/parisc/kernel/Makefile
+++ b/arch/parisc/kernel/Makefile
@@ -3,9 +3,9 @@
 # Makefile for arch/parisc/kernel
 #
 
-extra-y			:= head.o vmlinux.lds
+extra-y		:= vmlinux.lds
 
-obj-y	     	:= cache.o pacache.o setup.o pdt.o traps.o time.o irq.o \
+obj-y		:= head.o cache.o pacache.o setup.o pdt.o traps.o time.o irq.o \
 		   pa7300lc.o syscall.o entry.o sys_parisc.o firmware.o \
 		   ptrace.o hardware.o inventory.o drivers.o alternative.o \
 		   signal.o hpmc.o real2.o parisc_ksyms.o unaligned.o \
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 06d2d1f78f71..f264d9b2cb63 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -118,12 +118,12 @@ obj-$(CONFIG_PPC_FSL_BOOK3E)	+= cpu_setup_fsl_booke.o
 obj-$(CONFIG_PPC_DOORBELL)	+= dbell.o
 obj-$(CONFIG_JUMP_LABEL)	+= jump_label.o
 
-extra-$(CONFIG_PPC64)		:= head_64.o
-extra-$(CONFIG_PPC_BOOK3S_32)	:= head_book3s_32.o
-extra-$(CONFIG_40x)		:= head_40x.o
-extra-$(CONFIG_44x)		:= head_44x.o
-extra-$(CONFIG_FSL_BOOKE)	:= head_fsl_booke.o
-extra-$(CONFIG_PPC_8xx)		:= head_8xx.o
+obj-$(CONFIG_PPC64)		+= head_64.o
+obj-$(CONFIG_PPC_BOOK3S_32)	+= head_book3s_32.o
+obj-$(CONFIG_40x)		+= head_40x.o
+obj-$(CONFIG_44x)		+= head_44x.o
+obj-$(CONFIG_FSL_BOOKE)		+= head_fsl_booke.o
+obj-$(CONFIG_PPC_8xx)		+= head_8xx.o
 extra-y				+= vmlinux.lds
 
 obj-$(CONFIG_RELOCATABLE)	+= reloc_$(BITS).o
@@ -198,12 +198,12 @@ KCOV_INSTRUMENT_paca.o := n
 CFLAGS_setup_64.o		+= -fno-stack-protector
 CFLAGS_paca.o			+= -fno-stack-protector
 
-extra-$(CONFIG_PPC_FPU)		+= fpu.o
-extra-$(CONFIG_ALTIVEC)		+= vector.o
-extra-$(CONFIG_PPC64)		+= entry_64.o
-extra-$(CONFIG_PPC_OF_BOOT_TRAMPOLINE)	+= prom_init.o
+obj-$(CONFIG_PPC_FPU)		+= fpu.o
+obj-$(CONFIG_ALTIVEC)		+= vector.o
+obj-$(CONFIG_PPC64)		+= entry_64.o
+obj-$(CONFIG_PPC_OF_BOOT_TRAMPOLINE)	+= prom_init.o
 
-extra-$(CONFIG_PPC_OF_BOOT_TRAMPOLINE)	+= prom_init_check
+obj-$(CONFIG_PPC_OF_BOOT_TRAMPOLINE)	+= prom_init_check
 
 quiet_cmd_prom_init_check = PROMCHK $@
       cmd_prom_init_check = $(CONFIG_SHELL) $< "$(NM)" $(obj)/prom_init.o; touch $@
diff --git a/arch/riscv/kernel/Makefile b/arch/riscv/kernel/Makefile
index 33bb60a354cd..db6e4b1294ba 100644
--- a/arch/riscv/kernel/Makefile
+++ b/arch/riscv/kernel/Makefile
@@ -28,9 +28,9 @@ KASAN_SANITIZE_cpufeature.o := n
 endif
 endif
 
-extra-y += head.o
 extra-y += vmlinux.lds
 
+obj-y	+= head.o
 obj-y	+= soc.o
 obj-$(CONFIG_RISCV_ALTERNATIVE) += alternative.o
 obj-y	+= cpu.o
diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index 3cbfa9fddd9a..7ce00816b8df 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -33,7 +33,7 @@ CFLAGS_stacktrace.o	+= -fno-optimize-sibling-calls
 CFLAGS_dumpstack.o	+= -fno-optimize-sibling-calls
 CFLAGS_unwind_bc.o	+= -fno-optimize-sibling-calls
 
-obj-y	:= traps.o time.o process.o earlypgm.o early.o setup.o idle.o vtime.o
+obj-y	:= head64.o traps.o time.o process.o earlypgm.o early.o setup.o idle.o vtime.o
 obj-y	+= processor.o syscall.o ptrace.o signal.o cpcmd.o ebcdic.o nmi.o
 obj-y	+= debug.o irq.o ipl.o dis.o diag.o vdso.o cpufeature.o
 obj-y	+= sysinfo.o lgr.o os_info.o machine_kexec.o
@@ -42,7 +42,7 @@ obj-y	+= entry.o reipl.o relocate_kernel.o kdebugfs.o alternative.o
 obj-y	+= nospec-branch.o ipl_vmparm.o machine_kexec_reloc.o unwind_bc.o
 obj-y	+= smp.o text_amode31.o stacktrace.o
 
-extra-y				+= head64.o vmlinux.lds
+extra-y				+= vmlinux.lds
 
 obj-$(CONFIG_SYSFS)		+= nospec-sysfs.o
 CFLAGS_REMOVE_nospec-branch.o	+= $(CC_FLAGS_EXPOLINE)
diff --git a/arch/sh/kernel/Makefile b/arch/sh/kernel/Makefile
index aa0fbc9202b1..69cd9ac4b2ab 100644
--- a/arch/sh/kernel/Makefile
+++ b/arch/sh/kernel/Makefile
@@ -3,7 +3,7 @@
 # Makefile for the Linux/SuperH kernel.
 #
 
-extra-y	:= head_32.o vmlinux.lds
+extra-y	:= vmlinux.lds
 
 ifdef CONFIG_FUNCTION_TRACER
 # Do not profile debug and lowlevel utilities
@@ -12,7 +12,7 @@ endif
 
 CFLAGS_REMOVE_return_address.o = -pg
 
-obj-y	:= debugtraps.o dumpstack.o 		\
+obj-y	:= head_32.o debugtraps.o dumpstack.o				\
 	   idle.o io.o irq.o irq_32.o kdebugfs.o			\
 	   machvec.o nmi_debug.o process.o				\
 	   process_32.o ptrace.o ptrace_32.o				\
diff --git a/arch/sparc/kernel/Makefile b/arch/sparc/kernel/Makefile
index d3a0e072ebe8..b328e4a0bd57 100644
--- a/arch/sparc/kernel/Makefile
+++ b/arch/sparc/kernel/Makefile
@@ -7,8 +7,6 @@
 asflags-y := -ansi
 ccflags-y := -Werror
 
-extra-y     := head_$(BITS).o
-
 # Undefine sparc when processing vmlinux.lds - it is used
 # And teach CPP we are doing $(BITS) builds (for this case)
 CPPFLAGS_vmlinux.lds := -Usparc -m$(BITS)
@@ -22,6 +20,7 @@ CFLAGS_REMOVE_perf_event.o := -pg
 CFLAGS_REMOVE_pcr.o := -pg
 endif
 
+obj-y                   := head_$(BITS).o
 obj-$(CONFIG_SPARC64)   += urtt_fill.o
 obj-$(CONFIG_SPARC32)   += entry.o wof.o wuf.o
 obj-$(CONFIG_SPARC32)   += etrap_32.o
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index a20a5ebfacd7..956e50ca06e0 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -3,10 +3,6 @@
 # Makefile for the linux kernel.
 #
 
-extra-y	:= head_$(BITS).o
-extra-y	+= head$(BITS).o
-extra-y	+= ebda.o
-extra-y	+= platform-quirks.o
 extra-y	+= vmlinux.lds
 
 CPPFLAGS_vmlinux.lds += -U$(UTS_MACHINE)
@@ -42,7 +38,11 @@ KCOV_INSTRUMENT		:= n
 
 CFLAGS_irq.o := -I $(srctree)/$(src)/../include/asm/trace
 
-obj-y			:= process_$(BITS).o signal.o
+obj-y			+= head_$(BITS).o
+obj-y			+= head$(BITS).o
+obj-y			+= ebda.o
+obj-y			+= platform-quirks.o
+obj-y			+= process_$(BITS).o signal.o
 obj-$(CONFIG_COMPAT)	+= signal_compat.o
 obj-y			+= traps.o idt.o irq.o irq_$(BITS).o dumpstack_$(BITS).o
 obj-y			+= time.o ioport.o dumpstack.o nmi.o
diff --git a/arch/xtensa/kernel/Makefile b/arch/xtensa/kernel/Makefile
index 897c1c741058..f28b8e3d717e 100644
--- a/arch/xtensa/kernel/Makefile
+++ b/arch/xtensa/kernel/Makefile
@@ -3,9 +3,9 @@
 # Makefile for the Linux/Xtensa kernel.
 #
 
-extra-y := head.o vmlinux.lds
+extra-y := vmlinux.lds
 
-obj-y := align.o coprocessor.o entry.o irq.o platform.o process.o \
+obj-y := head.o align.o coprocessor.o entry.o irq.o platform.o process.o \
 	 ptrace.o setup.o signal.o stacktrace.o syscall.o time.o traps.o \
 	 vectors.o
 
diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index d7d3138c5ecc..4f74370ad1ee 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -70,13 +70,12 @@ quiet_cmd_vmlinux_objs = GEN     $@
 	for f in $(real-prereqs); do	\
 		case $${f} in		\
 		*libgcc.a) ;;		\
-		*.a) $(AR) t $${f} ;;	\
-		*) echo $${f} ;;	\
+		*) $(AR) t $${f} ;;	\
 		esac			\
 	done > $@
 
 targets += .vmlinux.objs
-.vmlinux.objs: $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
+.vmlinux.objs: vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
 	$(call if_changed,vmlinux_objs)
 
 vmlinux.o-if-present := $(wildcard vmlinux.o)
diff --git a/scripts/Makefile.vmlinux_o b/scripts/Makefile.vmlinux_o
index 84019814f33f..81a4e0484457 100644
--- a/scripts/Makefile.vmlinux_o
+++ b/scripts/Makefile.vmlinux_o
@@ -18,7 +18,7 @@ quiet_cmd_gen_initcalls_lds = GEN     $@
 	$(PERL) $(real-prereqs) > $@
 
 .tmp_initcalls.lds: $(srctree)/scripts/generate_initcall_order.pl \
-		$(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
+		vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
 	$(call if_changed,gen_initcalls_lds)
 
 targets := .tmp_initcalls.lds
@@ -55,7 +55,7 @@ quiet_cmd_ld_vmlinux.o = LD      $@
       cmd_ld_vmlinux.o = \
 	$(LD) ${KBUILD_LDFLAGS} -r -o $@ \
 	$(addprefix -T , $(initcalls-lds)) \
-	--whole-archive $(KBUILD_VMLINUX_OBJS) --no-whole-archive \
+	--whole-archive vmlinux.a --no-whole-archive \
 	--start-group $(KBUILD_VMLINUX_LIBS) --end-group \
 	$(cmd_objtool)
 
@@ -64,7 +64,7 @@ define rule_ld_vmlinux.o
 	$(call cmd,gen_objtooldep)
 endef
 
-vmlinux.o: $(initcalls-lds) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
+vmlinux.o: $(initcalls-lds) vmlinux.a $(KBUILD_VMLINUX_LIBS) FORCE
 	$(call if_changed_rule,ld_vmlinux.o)
 
 targets += vmlinux.o
diff --git a/scripts/clang-tools/gen_compile_commands.py b/scripts/clang-tools/gen_compile_commands.py
index 47da25b3ba7d..d800b2c0af97 100755
--- a/scripts/clang-tools/gen_compile_commands.py
+++ b/scripts/clang-tools/gen_compile_commands.py
@@ -109,20 +109,6 @@ def to_cmdfile(path):
     return os.path.join(dir, '.' + base + '.cmd')
 
 
-def cmdfiles_for_o(obj):
-    """Generate the iterator of .cmd files associated with the object
-
-    Yield the .cmd file used to build the given object
-
-    Args:
-        obj: The object path
-
-    Yields:
-        The path to .cmd file
-    """
-    yield to_cmdfile(obj)
-
-
 def cmdfiles_for_a(archive, ar):
     """Generate the iterator of .cmd files associated with the archive.
 
@@ -211,13 +197,10 @@ def main():
     for path in paths:
         # If 'path' is a directory, handle all .cmd files under it.
         # Otherwise, handle .cmd files associated with the file.
-        # Most of built-in objects are linked via archives (built-in.a or lib.a)
-        # but some objects are linked to vmlinux directly.
+        # built-in objects are linked via vmlinux.a
         # Modules are listed in modules.order.
         if os.path.isdir(path):
             cmdfiles = cmdfiles_in_dir(path)
-        elif path.endswith('.o'):
-            cmdfiles = cmdfiles_for_o(path)
         elif path.endswith('.a'):
             cmdfiles = cmdfiles_for_a(path, ar)
         elif path.endswith('modules.order'):
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 6a197d8a88ac..23ac13fd9d89 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -3,17 +3,15 @@
 #
 # link vmlinux
 #
-# vmlinux is linked from the objects selected by $(KBUILD_VMLINUX_OBJS) and
-# $(KBUILD_VMLINUX_LIBS). Most are built-in.a files from top-level directories
-# in the kernel tree, others are specified in arch/$(ARCH)/Makefile.
+# vmlinux is linked from the objects in vmlinux.a and $(KBUILD_VMLINUX_LIBS).
+# vmlinux.a contains objects that are linked unconditionally.
 # $(KBUILD_VMLINUX_LIBS) are archives which are linked conditionally
 # (not within --whole-archive), and do not require symbol indexes added.
 #
 # vmlinux
 #   ^
 #   |
-#   +--< $(KBUILD_VMLINUX_OBJS)
-#   |    +--< init/built-in.a drivers/built-in.a mm/built-in.a + more
+#   +--< vmlinux.a
 #   |
 #   +--< $(KBUILD_VMLINUX_LIBS)
 #   |    +--< lib/lib.a + more
@@ -67,7 +65,7 @@ vmlinux_link()
 		objs=vmlinux.o
 		libs=
 	else
-		objs="${KBUILD_VMLINUX_OBJS}"
+		objs=vmlinux.a
 		libs="${KBUILD_VMLINUX_LIBS}"
 	fi
 
-- 
2.34.1

[PATCH 15/15] kbuild: remove head-y syntax

[Masahiro Yamada]

Kbuild puts the objects listed in head-y at the head of vmlinux.
Conventionally, we do this for head*.S, which contains the kernel entry
point.

A counter approach is to control the section order in the linker script.
Actually, the code marked as __HEAD goes into the ".head.text" section,
which is placed before the normal ".text" section.

I do not know if both of them are needed. head-y is not mandatory.
If you can achieve the proper code placement by the linker script only,
it would be cleaner.

I collected the current head-y objects into head-object-list.txt. It is
a whitelist. My hope is it will be reduced in the long run.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---

 Documentation/kbuild/makefiles.rst |  9 ++---
 Makefile                           |  4 +--
 arch/alpha/Makefile                |  2 --
 arch/arc/Makefile                  |  2 --
 arch/arm/Makefile                  |  3 --
 arch/arm64/Makefile                |  3 --
 arch/csky/Makefile                 |  2 --
 arch/hexagon/Makefile              |  2 --
 arch/ia64/Makefile                 |  1 -
 arch/loongarch/Makefile            |  2 --
 arch/m68k/Makefile                 |  9 -----
 arch/microblaze/Makefile           |  1 -
 arch/mips/Makefile                 |  2 --
 arch/nios2/Makefile                |  1 -
 arch/openrisc/Makefile             |  2 --
 arch/parisc/Makefile               |  2 --
 arch/powerpc/Makefile              | 12 -------
 arch/riscv/Makefile                |  2 --
 arch/s390/Makefile                 |  2 --
 arch/sh/Makefile                   |  2 --
 arch/sparc/Makefile                |  2 --
 arch/x86/Makefile                  |  5 ---
 arch/xtensa/Makefile               |  2 --
 scripts/head-object-list.txt       | 53 ++++++++++++++++++++++++++++++
 24 files changed, 60 insertions(+), 67 deletions(-)
 create mode 100644 scripts/head-object-list.txt

diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
index 07c7e5a843c1..528c54d56c09 100644
--- a/Documentation/kbuild/makefiles.rst
+++ b/Documentation/kbuild/makefiles.rst
@@ -1065,8 +1065,7 @@ When kbuild executes, the following steps are followed (roughly):
    - The values of the above variables are expanded in arch/$(SRCARCH)/Makefile.
 5) All object files are then linked and the resulting file vmlinux is
    located at the root of the obj tree.
-   The very first objects linked are listed in head-y, assigned by
-   arch/$(SRCARCH)/Makefile.
+   The very first objects linked are listed in scripts/head-object-list.txt.
 6) Finally, the architecture-specific part does any required post processing
    and builds the final bootimage.
    - This includes building boot records
@@ -1214,6 +1213,9 @@ When kbuild executes, the following steps are followed (roughly):
 	All object files for vmlinux. They are linked to vmlinux in the same
 	order as listed in KBUILD_VMLINUX_OBJS.
 
+	The objects listed in scripts/head-object-list.txt are exceptions;
+	they are placed before the other objects.
+
     KBUILD_VMLINUX_LIBS
 
 	All .a "lib" files for vmlinux. KBUILD_VMLINUX_OBJS and
@@ -1257,8 +1259,7 @@ When kbuild executes, the following steps are followed (roughly):
 	machinery is all architecture-independent.
 
 
-	head-y, core-y, libs-y, drivers-y
-	    $(head-y) lists objects to be linked first in vmlinux.
+	core-y, libs-y, drivers-y
 
 	    $(libs-y) lists directories where a lib.a archive can be located.
 
diff --git a/Makefile b/Makefile
index d74aa4552d35..08e69448caf4 100644
--- a/Makefile
+++ b/Makefile
@@ -1159,10 +1159,10 @@ quiet_cmd_ar_vmlinux.a = AR      $@
       cmd_ar_vmlinux.a = \
 	rm -f $@; \
 	$(AR) cDPrST $@ $(KBUILD_VMLINUX_OBJS); \
-	$(AR) mPi $$($(AR) t $@| head -n1) $@ $(head-y)
+	$(AR) mPi $$($(AR) t $@| head -n1) $@ $$($(AR) t $@ | grep -F --file=$(srctree)/scripts/head-object-list.txt)
 
 targets += vmlinux.a
-vmlinux.a: $(KBUILD_VMLINUX_OBJS) FORCE
+vmlinux.a: $(KBUILD_VMLINUX_OBJS) scripts/head-object-list.txt FORCE
 	$(call if_changed,ar_vmlinux.a)
 
 targets += vmlinux.o
diff --git a/arch/alpha/Makefile b/arch/alpha/Makefile
index 881cb913e23a..45158024085e 100644
--- a/arch/alpha/Makefile
+++ b/arch/alpha/Makefile
@@ -36,8 +36,6 @@ cflags-y				+= $(cpuflags-y)
 # BWX is most important, but we don't really want any emulation ever.
 KBUILD_CFLAGS += $(cflags-y) -Wa,-mev6
 
-head-y := arch/alpha/kernel/head.o
-
 libs-y				+= arch/alpha/lib/
 
 # export what is needed by arch/alpha/boot/Makefile
diff --git a/arch/arc/Makefile b/arch/arc/Makefile
index efc54f3e35e0..329400a1c355 100644
--- a/arch/arc/Makefile
+++ b/arch/arc/Makefile
@@ -82,8 +82,6 @@ KBUILD_CFLAGS	+= $(cflags-y)
 KBUILD_AFLAGS	+= $(KBUILD_CFLAGS)
 KBUILD_LDFLAGS	+= $(ldflags-y)
 
-head-y		:= arch/arc/kernel/head.o
-
 # w/o this dtb won't embed into kernel binary
 core-y		+= arch/arc/boot/dts/
 
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 56f655deebb1..29d15c9a433e 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -134,9 +134,6 @@ KBUILD_AFLAGS	+=$(CFLAGS_ABI) $(AFLAGS_ISA) $(arch-y) $(tune-y) -include asm/uni
 
 CHECKFLAGS	+= -D__arm__
 
-#Default value
-head-y		:= arch/arm/kernel/head$(MMUEXT).o
-
 # Text offset. This list is sorted numerically by address in order to
 # provide a means to avoid/resolve conflicts in multi-arch kernels.
 # Note: the 32kB below this value is reserved for use by the kernel
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 6d9d4a58b898..6e03f15bb041 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -133,9 +133,6 @@ ifeq ($(CONFIG_DYNAMIC_FTRACE_WITH_REGS),y)
   CC_FLAGS_FTRACE := -fpatchable-function-entry=2
 endif
 
-# Default value
-head-y		:= arch/arm64/kernel/head.o
-
 ifeq ($(CONFIG_KASAN_SW_TAGS), y)
 KASAN_SHADOW_SCALE_SHIFT := 4
 else ifeq ($(CONFIG_KASAN_GENERIC), y)
diff --git a/arch/csky/Makefile b/arch/csky/Makefile
index 4e1d619fd5c6..0e4237e55758 100644
--- a/arch/csky/Makefile
+++ b/arch/csky/Makefile
@@ -59,8 +59,6 @@ LDFLAGS += -EL
 
 KBUILD_AFLAGS += $(KBUILD_CFLAGS)
 
-head-y := arch/csky/kernel/head.o
-
 core-y += arch/csky/$(CSKYABI)/
 
 libs-y += arch/csky/lib/ \
diff --git a/arch/hexagon/Makefile b/arch/hexagon/Makefile
index 44312bc147d8..92d005958dfb 100644
--- a/arch/hexagon/Makefile
+++ b/arch/hexagon/Makefile
@@ -32,5 +32,3 @@ KBUILD_LDFLAGS += $(ldflags-y)
 TIR_NAME := r19
 KBUILD_CFLAGS += -ffixed-$(TIR_NAME) -DTHREADINFO_REG=$(TIR_NAME) -D__linux__
 KBUILD_AFLAGS += -DTHREADINFO_REG=$(TIR_NAME)
-
-head-y := arch/hexagon/kernel/head.o
diff --git a/arch/ia64/Makefile b/arch/ia64/Makefile
index e55c2f138656..56c4bb276b6e 100644
--- a/arch/ia64/Makefile
+++ b/arch/ia64/Makefile
@@ -44,7 +44,6 @@ quiet_cmd_objcopy = OBJCOPY $@
 cmd_objcopy = $(OBJCOPY) $(OBJCOPYFLAGS) $(OBJCOPYFLAGS_$(@F)) $< $@
 
 KBUILD_CFLAGS += $(cflags-y)
-head-y := arch/ia64/kernel/head.o
 
 libs-y				+= arch/ia64/lib/
 
diff --git a/arch/loongarch/Makefile b/arch/loongarch/Makefile
index ec3de6191276..131fc210c2bf 100644
--- a/arch/loongarch/Makefile
+++ b/arch/loongarch/Makefile
@@ -72,8 +72,6 @@ CHECKFLAGS += $(shell $(CC) $(KBUILD_CFLAGS) -dM -E -x c /dev/null | \
 	sed -e "s/^\#define /-D'/" -e "s/ /'='/" -e "s/$$/'/" -e 's/\$$/&&/g')
 endif
 
-head-y := arch/loongarch/kernel/head.o
-
 libs-y += arch/loongarch/lib/
 
 ifeq ($(KBUILD_EXTMOD),)
diff --git a/arch/m68k/Makefile b/arch/m68k/Makefile
index e358605b70ba..43e39040d3ac 100644
--- a/arch/m68k/Makefile
+++ b/arch/m68k/Makefile
@@ -86,15 +86,6 @@ ifdef CONFIG_KGDB
 KBUILD_CFLAGS := $(subst -fomit-frame-pointer,,$(KBUILD_CFLAGS)) -g
 endif
 
-#
-# Select the assembler head startup code. Order is important. The default
-# head code is first, processor specific selections can override it after.
-#
-head-y				:= arch/m68k/kernel/head.o
-head-$(CONFIG_SUN3)		:= arch/m68k/kernel/sun3-head.o
-head-$(CONFIG_M68000)		:= arch/m68k/68000/head.o
-head-$(CONFIG_COLDFIRE)		:= arch/m68k/coldfire/head.o
-
 libs-y				+= arch/m68k/lib/
 
 
diff --git a/arch/microblaze/Makefile b/arch/microblaze/Makefile
index 1826d9ce4459..3f8a86c4336a 100644
--- a/arch/microblaze/Makefile
+++ b/arch/microblaze/Makefile
@@ -48,7 +48,6 @@ CPUFLAGS-1 += $(call cc-option,-mcpu=v$(CPU_VER))
 # r31 holds current when in kernel mode
 KBUILD_CFLAGS += -ffixed-r31 $(CPUFLAGS-y) $(CPUFLAGS-1) $(CPUFLAGS-2)
 
-head-y := arch/microblaze/kernel/head.o
 libs-y += arch/microblaze/lib/
 
 boot := arch/microblaze/boot
diff --git a/arch/mips/Makefile b/arch/mips/Makefile
index 4d2a3e73fc45..b296e33f8e33 100644
--- a/arch/mips/Makefile
+++ b/arch/mips/Makefile
@@ -324,8 +324,6 @@ endif
 
 OBJCOPYFLAGS		+= --remove-section=.reginfo
 
-head-y := arch/mips/kernel/head.o
-
 libs-y			+= arch/mips/lib/
 libs-$(CONFIG_MIPS_FP_SUPPORT) += arch/mips/math-emu/
 
diff --git a/arch/nios2/Makefile b/arch/nios2/Makefile
index 3f34e6831863..f1ff4ce0f1a2 100644
--- a/arch/nios2/Makefile
+++ b/arch/nios2/Makefile
@@ -37,7 +37,6 @@ KBUILD_CFLAGS += -DUTS_SYSNAME=\"$(UTS_SYSNAME)\"
 KBUILD_CFLAGS += -fno-builtin
 KBUILD_CFLAGS += -G 0
 
-head-y		:= arch/nios2/kernel/head.o
 libs-y		+= arch/nios2/lib/ $(LIBGCC)
 
 INSTALL_PATH ?= /tftpboot
diff --git a/arch/openrisc/Makefile b/arch/openrisc/Makefile
index b446510173cd..68249521db5a 100644
--- a/arch/openrisc/Makefile
+++ b/arch/openrisc/Makefile
@@ -55,8 +55,6 @@ ifeq ($(CONFIG_OPENRISC_HAVE_INST_SEXT),y)
 	KBUILD_CFLAGS += $(call cc-option,-msext)
 endif
 
-head-y 		:= arch/openrisc/kernel/head.o
-
 libs-y		+= $(LIBGCC)
 
 PHONY += vmlinux.bin
diff --git a/arch/parisc/Makefile b/arch/parisc/Makefile
index e38d993d87f2..a2d8600521f9 100644
--- a/arch/parisc/Makefile
+++ b/arch/parisc/Makefile
@@ -113,8 +113,6 @@ cflags-$(CONFIG_PA7100LC)	+= -march=1.1 -mschedule=7100LC
 cflags-$(CONFIG_PA7300LC)	+= -march=1.1 -mschedule=7300
 cflags-$(CONFIG_PA8X00)		+= -march=2.0 -mschedule=8000
 
-head-y			:= arch/parisc/kernel/head.o 
-
 KBUILD_CFLAGS	+= $(cflags-y)
 LIBGCC		:= $(shell $(CC) -print-libgcc-file-name)
 export LIBGCC
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index fb607758eeca..491cdeed9a72 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -220,18 +220,6 @@ KBUILD_CFLAGS += $(cpu-as-y)
 KBUILD_AFLAGS += $(aflags-y)
 KBUILD_CFLAGS += $(cflags-y)
 
-head-$(CONFIG_PPC64)		:= arch/powerpc/kernel/head_64.o
-head-$(CONFIG_PPC_BOOK3S_32)	:= arch/powerpc/kernel/head_book3s_32.o
-head-$(CONFIG_PPC_8xx)		:= arch/powerpc/kernel/head_8xx.o
-head-$(CONFIG_40x)		:= arch/powerpc/kernel/head_40x.o
-head-$(CONFIG_44x)		:= arch/powerpc/kernel/head_44x.o
-head-$(CONFIG_FSL_BOOKE)	:= arch/powerpc/kernel/head_fsl_booke.o
-
-head-$(CONFIG_PPC64)		+= arch/powerpc/kernel/entry_64.o
-head-$(CONFIG_PPC_FPU)		+= arch/powerpc/kernel/fpu.o
-head-$(CONFIG_ALTIVEC)		+= arch/powerpc/kernel/vector.o
-head-$(CONFIG_PPC_OF_BOOT_TRAMPOLINE)  += arch/powerpc/kernel/prom_init.o
-
 # Default to zImage, override when needed
 all: zImage
 
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index 3fa8ef336822..e013df8e7b8b 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -110,8 +110,6 @@ else
 KBUILD_IMAGE	:= $(boot)/Image.gz
 endif
 
-head-y := arch/riscv/kernel/head.o
-
 libs-y += arch/riscv/lib/
 libs-$(CONFIG_EFI_STUB) += $(objtree)/drivers/firmware/efi/libstub/lib.a
 
diff --git a/arch/s390/Makefile b/arch/s390/Makefile
index 4cb5d17e7ead..de6d8b2ea4d8 100644
--- a/arch/s390/Makefile
+++ b/arch/s390/Makefile
@@ -119,8 +119,6 @@ export KBUILD_CFLAGS_DECOMPRESSOR
 
 OBJCOPYFLAGS	:= -O binary
 
-head-y		:= arch/s390/kernel/head64.o
-
 libs-y		+= arch/s390/lib/
 drivers-y	+= drivers/s390/
 
diff --git a/arch/sh/Makefile b/arch/sh/Makefile
index b39412bf91fb..5c8776482530 100644
--- a/arch/sh/Makefile
+++ b/arch/sh/Makefile
@@ -114,8 +114,6 @@ endif
 
 export ld-bfd
 
-head-y	:= arch/sh/kernel/head_32.o
-
 # Mach groups
 machdir-$(CONFIG_SOLUTION_ENGINE)		+= mach-se
 machdir-$(CONFIG_SH_HP6XX)			+= mach-hp6xx
diff --git a/arch/sparc/Makefile b/arch/sparc/Makefile
index fe58a410b4ce..a4ea5b05f288 100644
--- a/arch/sparc/Makefile
+++ b/arch/sparc/Makefile
@@ -56,8 +56,6 @@ endif
 
 endif
 
-head-y                 := arch/sparc/kernel/head_$(BITS).o
-
 libs-y                 += arch/sparc/prom/
 libs-y                 += arch/sparc/lib/
 
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index bafbd905e6e7..9afd323c6916 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -234,11 +234,6 @@ archheaders:
 ###
 # Kernel objects
 
-head-y := arch/x86/kernel/head_$(BITS).o
-head-y += arch/x86/kernel/head$(BITS).o
-head-y += arch/x86/kernel/ebda.o
-head-y += arch/x86/kernel/platform-quirks.o
-
 libs-y  += arch/x86/lib/
 
 # drivers-y are linked after core-y
diff --git a/arch/xtensa/Makefile b/arch/xtensa/Makefile
index 5097caa7bf0c..bfd8e433ed62 100644
--- a/arch/xtensa/Makefile
+++ b/arch/xtensa/Makefile
@@ -55,8 +55,6 @@ KBUILD_CPPFLAGS += $(patsubst %,-I$(srctree)/%include,$(vardirs) $(plfdirs))
 
 KBUILD_DEFCONFIG := iss_defconfig
 
-head-y		:= arch/xtensa/kernel/head.o
-
 libs-y		+= arch/xtensa/lib/
 
 boot		:= arch/xtensa/boot
diff --git a/scripts/head-object-list.txt b/scripts/head-object-list.txt
new file mode 100644
index 000000000000..6610e19d0247
--- /dev/null
+++ b/scripts/head-object-list.txt
@@ -0,0 +1,53 @@
+# Head objects
+#
+# The objects listed here are placed at the head of vmlinux. A typical use-case
+# is an object that contains the entry point. This is kept for compatibility
+# with head-y, Kbuild used to support.
+#
+# A counter approach is to control the section placement in the linker script.
+# The code marked as __HEAD goes into the ".head.text" section, which is placed
+# before the normal ".text" section.
+#
+# If you can achieve the correct code ordering by linker script, please delete
+# the entry from this file.
+#
+arch/alpha/kernel/head.o
+arch/arc/kernel/head.o
+arch/arm/kernel/head-nommu.o
+arch/arm/kernel/head.o
+arch/arm64/kernel/head.o
+arch/csky/kernel/head.o
+arch/hexagon/kernel/head.o
+arch/ia64/kernel/head.o
+arch/loongarch/kernel/head.o
+arch/m68k/68000/head.o
+arch/m68k/coldfire/head.o
+arch/m68k/kernel/head.o
+arch/m68k/kernel/sun3-head.o
+arch/microblaze/kernel/head.o
+arch/mips/kernel/head.o
+arch/nios2/kernel/head.o
+arch/openrisc/kernel/head.o
+arch/parisc/kernel/head.o
+arch/powerpc/kernel/head_40x.o
+arch/powerpc/kernel/head_44x.o
+arch/powerpc/kernel/head_64.o
+arch/powerpc/kernel/head_8xx.o
+arch/powerpc/kernel/head_book3s_32.o
+arch/powerpc/kernel/head_fsl_booke.o
+arch/powerpc/kernel/entry_64.o
+arch/powerpc/kernel/fpu.o
+arch/powerpc/kernel/vector.o
+arch/powerpc/kernel/prom_init.o
+arch/riscv/kernel/head.o
+arch/s390/kernel/head64.o
+arch/sh/kernel/head_32.o
+arch/sparc/kernel/head_32.o
+arch/sparc/kernel/head_64.o
+arch/x86/kernel/head_32.o
+arch/x86/kernel/head_64.o
+arch/x86/kernel/head32.o
+arch/x86/kernel/head64.o
+arch/x86/kernel/ebda.o
+arch/x86/kernel/platform-quirks.o
+arch/xtensa/kernel/head.o
-- 
2.34.1

Re: [PATCH 05/15] kbuild: build init/built-in.a just once

[Masahiro Yamada]

On Sun, Aug 28, 2022 at 11:40 AM Masahiro Yamada <masahiroy@kernel.org> wrote:


> --- a/init/Makefile
> +++ b/init/Makefile
> @@ -19,20 +19,47 @@ mounts-y                    := do_mounts.o
>  mounts-$(CONFIG_BLK_DEV_RAM)   += do_mounts_rd.o
>  mounts-$(CONFIG_BLK_DEV_INITRD)        += do_mounts_initrd.o
>
> -# dependencies on generated files need to be listed explicitly
> -$(obj)/version.o: include/generated/compile.h
> +#
> +# UTS_VERSION
> +#
> +
> +smp-flag-$(CONFIG_SMP)                 := SMP
> +preempt-flag-$(CONFIG_PREEMPT_BUILD)   := PREEMPT
> +preempt-flag-$(CONFIG_PREEMPT_DYNAMIC) := PREEMPT_DYNAMIC
> +preempt-flag-$(CONFIG_PREEMPT_RT)      := PREEMPT_RT
> +
> +build-version = $(or $(KBUILD_BUILD_VERSION), $(build-version-auto))
> +build-timestamp = $(or $(KBUILD_BUILD_TIMESTAMP), $(build-timestamp-auto))
> +
> +# Maximum length of UTS_VERSION is 64 chars
> +filechk_uts_version = \
> +       utsver=$$(echo '$(pound)'"$(build-version)" $(smp-flag-y) $(preempt-flag-y) "$(build-timestamp)" | cut -b -64); \
> +       echo '$(pound)'define UTS_VERSION \""$${utsver}"\"
> +
> +#
> +# Build version.c with temporary UTS_VERSION
> +#
> +
> +$(obj)/utsversion-tmp.h: FORCE
> +       $(call filechk,uts_version)


I missed to clean up init/utsversion-tmp.h.

I patched like follows, and also added it to init/.gitignore.




diff --git a/init/Makefile b/init/Makefile
index 63f53d210cad..ba90eb817185 100644
--- a/init/Makefile
+++ b/init/Makefile
@@ -43,6 +43,8 @@ filechk_uts_version = \
 $(obj)/utsversion-tmp.h: FORCE
        $(call filechk,uts_version)

+clean-files += utsversion-tmp.h
+
 $(obj)/version.o: include/generated/compile.h $(obj)/utsversion-tmp.h
 CFLAGS_version.o := -include $(obj)/utsversion-tmp.h










-- 
Best Regards
Masahiro Yamada

Re: [PATCH 00/15] kbuild: various cleanups

[Masahiro Yamada]

On Sun, Aug 28, 2022 at 11:40 AM Masahiro Yamada <masahiroy@kernel.org> wrote:
>
>   - Avoid updating init/built-in.a twice
>   - Run modpost just once instead of twice
>   - Link vmlinux and modules in parallel
>   - Remove head-y syntax
>
> These are ground works to make the further refactoring possible.
>
> This patch set is applicable after the following series:
>   https://patchwork.kernel.org/project/linux-kbuild/list/?series=669437
>
>
> Masahiro Yamada (15):
>   kbuild: remove duplicated dependency between modules and modules_check
>   kbuild: refactor single builds of *.ko
>   kbuild: move 'PHONY += modules_prepare' to the common part
>   init/version.c: remove #include <linux/version.h>
>   kbuild: build init/built-in.a just once
>   kbuild: generate include/generated/compile.h in top Makefile
>   scripts/mkcompile_h: move LC_ALL=C to '$LD -v'
>   Revert "kbuild: Make scripts/compile.h when sh != bash"
>   kbuild: rename modules.order in sub-directories to .modules.order
>   kbuild: move core-y in top Makefile to ./Kbuild
>   kbuild: move .vmlinux.objs rule to Makefile.modpost
>   kbuild: move vmlinux.o rule to the top Makefile
>   kbuild: unify two modpost invocations
>   kbuild: use obj-y instead extra-y for objects placed at the head
>   kbuild: remove head-y syntax



I moved 01-08 to for-next.

10 broke single target builds.

I will send v2 for the rest.






>  Documentation/kbuild/makefiles.rst          |  27 +----
>  Kbuild                                      |  16 +++
>  Makefile                                    | 120 ++++++++++++--------
>  arch/alpha/Makefile                         |   2 -
>  arch/alpha/kernel/Makefile                  |   4 +-
>  arch/arc/Makefile                           |   2 -
>  arch/arc/kernel/Makefile                    |   4 +-
>  arch/arm/Makefile                           |   3 -
>  arch/arm/kernel/Makefile                    |   4 +-
>  arch/arm64/Makefile                         |   3 -
>  arch/arm64/kernel/Makefile                  |   4 +-
>  arch/csky/Makefile                          |   2 -
>  arch/csky/kernel/Makefile                   |   4 +-
>  arch/hexagon/Makefile                       |   2 -
>  arch/hexagon/kernel/Makefile                |   3 +-
>  arch/ia64/Makefile                          |   1 -
>  arch/ia64/kernel/Makefile                   |   4 +-
>  arch/loongarch/Makefile                     |   2 -
>  arch/loongarch/kernel/Makefile              |   4 +-
>  arch/m68k/68000/Makefile                    |   2 +-
>  arch/m68k/Makefile                          |   9 --
>  arch/m68k/coldfire/Makefile                 |   2 +-
>  arch/m68k/kernel/Makefile                   |  21 ++--
>  arch/microblaze/Makefile                    |   1 -
>  arch/microblaze/kernel/Makefile             |   4 +-
>  arch/mips/Makefile                          |   2 -
>  arch/mips/kernel/Makefile                   |   4 +-
>  arch/nios2/Makefile                         |   1 -
>  arch/nios2/kernel/Makefile                  |   2 +-
>  arch/openrisc/Makefile                      |   2 -
>  arch/openrisc/kernel/Makefile               |   4 +-
>  arch/parisc/Makefile                        |   2 -
>  arch/parisc/kernel/Makefile                 |   4 +-
>  arch/powerpc/Makefile                       |  12 --
>  arch/powerpc/kernel/Makefile                |  22 ++--
>  arch/riscv/Makefile                         |   2 -
>  arch/riscv/kernel/Makefile                  |   2 +-
>  arch/s390/Makefile                          |   2 -
>  arch/s390/boot/version.c                    |   1 +
>  arch/s390/kernel/Makefile                   |   4 +-
>  arch/sh/Makefile                            |   2 -
>  arch/sh/kernel/Makefile                     |   4 +-
>  arch/sparc/Makefile                         |   2 -
>  arch/sparc/kernel/Makefile                  |   3 +-
>  arch/x86/Makefile                           |   5 -
>  arch/x86/boot/compressed/kaslr.c            |   1 +
>  arch/x86/boot/version.c                     |   1 +
>  arch/x86/kernel/Makefile                    |  10 +-
>  arch/xtensa/Makefile                        |   2 -
>  arch/xtensa/kernel/Makefile                 |   4 +-
>  init/Makefile                               |  55 ++++++---
>  init/build-version                          |  10 ++
>  init/version-timestamp.c                    |  31 +++++
>  init/version.c                              |  37 +++---
>  scripts/Makefile.build                      |  20 ++--
>  scripts/Makefile.lib                        |   8 +-
>  scripts/Makefile.modfinal                   |   2 +-
>  scripts/Makefile.modpost                    | 112 ++++++++----------
>  scripts/Makefile.vmlinux_o                  |   6 +-
>  scripts/clang-tools/gen_compile_commands.py |  19 +---
>  scripts/head-object-list.txt                |  53 +++++++++
>  scripts/link-vmlinux.sh                     |  51 ++-------
>  scripts/mkcompile_h                         |  96 ++--------------
>  63 files changed, 393 insertions(+), 457 deletions(-)
>  create mode 100755 init/build-version
>  create mode 100644 init/version-timestamp.c
>  create mode 100644 scripts/head-object-list.txt
>
> --
> 2.34.1
>


-- 
Best Regards
Masahiro Yamada

Re: [PATCH 05/15] kbuild: build init/built-in.a just once

[Nathan Chancellor]

Hi Masahiro,

On Sun, Aug 28, 2022 at 11:39:53AM +0900, Masahiro Yamada wrote:
> Kbuild builds init/built-in.a twice; first during the ordinary
> directory descending, second from scripts/link-vmlinux.sh.
> 
> We do this because UTS_VERSION contains the build version and the
> timestamp. We cannot update it during the normal directory traversal
> since we do not yet know if we need to update vmlinux. UTS_VERSION is
> temporarily calculated, but omitted from the update check. Otherwise,
> vmlinux would be rebuilt every time.
> 
> When Kbuild results in running link-vmlinux.sh, it increments the
> version number in the .version file and takes the timestamp at that
> time to really fix UTS_VERSION.
> 
> However, updating the same file twice is a footgun. To avoid nasty
> timestamp issues, all build artifacts that depend on init/built-in.a
> must be atomically generated in link-vmlinux.sh, where some of them
> do not need rebuilding.
> 
> To fix this issue, this commit changes as follows:
> 
> [1] Split UTS_VERSION out to include/generated/utsversion.h from
>     include/generated/compile.h
> 
>     include/generated/utsversion.h is generated just before the
>     vmlinux link. It is generated under include/generated/ because
>     some decompressors (s390, x86) use UTS_VERSION.
> 
> [2] Split init_uts_ns and linux_banner out to init/version-timestamp.c
>     from init/version.c
> 
>     init_uts_ns and linux_banner contain UTS_VERSION. During the ordinary
>     directory descending, they are compiled with __weak and used to
>     determine if vmlinux needs relinking. Just before the vmlinux link,
>     they are compiled without __weak to embed the real version and
>     timestamp.
> 
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

<snip>

> diff --git a/init/build-version b/init/build-version
> new file mode 100755
> index 000000000000..39225104f14d
> --- /dev/null
> +++ b/init/build-version
> @@ -0,0 +1,10 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0-only
> +
> +VERSION=$(cat .version) 2>/dev/null &&
> +VERSION=$(expr $VERSION + 1) 2>/dev/null ||
> +VERSION=1
> +
> +echo ${VERSION} > .version
> +
> +echo ${VERSION}

I am seeing

  cat: .version: No such file or directory

at some point in nearly all of my builds in -next. Does the 2>/dev/null
want to be moved into the subshell?

Cheers,
Nathan

Re: [PATCH 05/15] kbuild: build init/built-in.a just once

[Masahiro Yamada]

On Tue, Sep 13, 2022 at 5:32 PM Nathan Chancellor <nathan@kernel.org> wrote:
>
> Hi Masahiro,
>
> On Sun, Aug 28, 2022 at 11:39:53AM +0900, Masahiro Yamada wrote:
> > Kbuild builds init/built-in.a twice; first during the ordinary
> > directory descending, second from scripts/link-vmlinux.sh.
> >
> > We do this because UTS_VERSION contains the build version and the
> > timestamp. We cannot update it during the normal directory traversal
> > since we do not yet know if we need to update vmlinux. UTS_VERSION is
> > temporarily calculated, but omitted from the update check. Otherwise,
> > vmlinux would be rebuilt every time.
> >
> > When Kbuild results in running link-vmlinux.sh, it increments the
> > version number in the .version file and takes the timestamp at that
> > time to really fix UTS_VERSION.
> >
> > However, updating the same file twice is a footgun. To avoid nasty
> > timestamp issues, all build artifacts that depend on init/built-in.a
> > must be atomically generated in link-vmlinux.sh, where some of them
> > do not need rebuilding.
> >
> > To fix this issue, this commit changes as follows:
> >
> > [1] Split UTS_VERSION out to include/generated/utsversion.h from
> >     include/generated/compile.h
> >
> >     include/generated/utsversion.h is generated just before the
> >     vmlinux link. It is generated under include/generated/ because
> >     some decompressors (s390, x86) use UTS_VERSION.
> >
> > [2] Split init_uts_ns and linux_banner out to init/version-timestamp.c
> >     from init/version.c
> >
> >     init_uts_ns and linux_banner contain UTS_VERSION. During the ordinary
> >     directory descending, they are compiled with __weak and used to
> >     determine if vmlinux needs relinking. Just before the vmlinux link,
> >     they are compiled without __weak to embed the real version and
> >     timestamp.
> >
> > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
>
> <snip>
>
> > diff --git a/init/build-version b/init/build-version
> > new file mode 100755
> > index 000000000000..39225104f14d
> > --- /dev/null
> > +++ b/init/build-version
> > @@ -0,0 +1,10 @@
> > +#!/bin/sh
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +
> > +VERSION=$(cat .version) 2>/dev/null &&
> > +VERSION=$(expr $VERSION + 1) 2>/dev/null ||
> > +VERSION=1
> > +
> > +echo ${VERSION} > .version
> > +
> > +echo ${VERSION}
>
> I am seeing
>
>   cat: .version: No such file or directory


Thanks, Nathan.



I did not notice it because /bin/sh is a symlink to dash
on my machine.
I see the warning by running it with bash.



$ rm -f .version ; dash init/build-version
1
$ rm -f .version ; bash init/build-version
cat: .version: No such file or directory
1




>
> at some point in nearly all of my builds in -next. Does the 2>/dev/null
> want to be moved into the subshell?


Agree.
I will fix it up locally.


Thanks.

>
> Cheers,
> Nathan



-- 
Best Regards
Masahiro Yamada

RE: [PATCH 05/15] kbuild: build init/built-in.a just once

[David Laight]

...
> > +VERSION=$(cat .version) 2>/dev/null &&
> > +VERSION=$(expr $VERSION + 1) 2>/dev/null ||
> > +VERSION=1

What's wrong with:
VERSION=$(($(cat .version 2>/dev/null) + 1))

If you are worried about .version not containing a valid
number and $((...)) failing then use ${VERSION:-1} later.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

Re: [PATCH 05/15] kbuild: build init/built-in.a just once

[Masahiro Yamada]

On Wed, Sep 14, 2022 at 6:46 PM David Laight <David.Laight@aculab.com> wrote:
>
> ...
> > > +VERSION=$(cat .version) 2>/dev/null &&
> > > +VERSION=$(expr $VERSION + 1) 2>/dev/null ||
> > > +VERSION=1
>
> What's wrong with:
> VERSION=$(($(cat .version 2>/dev/null) + 1))


One reason was, the original code used 'expr'.



> If you are worried about .version not containing a valid
> number and $((...)) failing then use ${VERSION:-1} later.


Maybe another reason is,
I want to make the behavior deterministic when
the .version file contains a non-integer string.




$ unset FOO
$ echo FOO > .version
$ echo $(($(cat .version 2>/dev/null) + 1))
1


$ export FOO=100
$ echo FOO > .version
$ echo $(($(cat .version 2>/dev/null) + 1))
101




I want the script to consistently return 1
whether or not 'FOO' is available in the user's environment.






>         David
>
> -
> Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
> Registration No: 1397386 (Wales)
>


-- 
Best Regards
Masahiro Yamada

Re: [PATCH 05/15] kbuild: build init/built-in.a just once

[Jon Hunter]

Hi Masahiro

On 28/08/2022 03:39, Masahiro Yamada wrote:
> Kbuild builds init/built-in.a twice; first during the ordinary
> directory descending, second from scripts/link-vmlinux.sh.
> 
> We do this because UTS_VERSION contains the build version and the
> timestamp. We cannot update it during the normal directory traversal
> since we do not yet know if we need to update vmlinux. UTS_VERSION is
> temporarily calculated, but omitted from the update check. Otherwise,
> vmlinux would be rebuilt every time.
> 
> When Kbuild results in running link-vmlinux.sh, it increments the
> version number in the .version file and takes the timestamp at that
> time to really fix UTS_VERSION.
> 
> However, updating the same file twice is a footgun. To avoid nasty
> timestamp issues, all build artifacts that depend on init/built-in.a
> must be atomically generated in link-vmlinux.sh, where some of them
> do not need rebuilding.
> 
> To fix this issue, this commit changes as follows:
> 
> [1] Split UTS_VERSION out to include/generated/utsversion.h from
>      include/generated/compile.h
> 
>      include/generated/utsversion.h is generated just before the
>      vmlinux link. It is generated under include/generated/ because
>      some decompressors (s390, x86) use UTS_VERSION.
> 
> [2] Split init_uts_ns and linux_banner out to init/version-timestamp.c
>      from init/version.c
> 
>      init_uts_ns and linux_banner contain UTS_VERSION. During the ordinary
>      directory descending, they are compiled with __weak and used to
>      determine if vmlinux needs relinking. Just before the vmlinux link,
>      they are compiled without __weak to embed the real version and
>      timestamp.
> 
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>


Since this change I have noticed that the kernel image (at least on ARM64) now contains two version strings ...

$ strings arch/arm64/boot/Image | grep "Linux version"
Linux version 6.0.0-rc7-00011-g2df8220cc511 (jonathanh@moonraker) (aarch64-linux-gnu-gcc (Linaro GCC 6.4-2017.08) 6.4.1 20170707, GNU ld (Linaro_Binutils-2017.08) 2.27.0.20161019) # SMP PREEMPT
Linux version 6.0.0-rc7-00011-g2df8220cc511 (jonathanh@moonraker) (aarch64-linux-gnu-gcc (Linaro GCC 6.4-2017.08) 6.4.1 20170707, GNU ld (Linaro_Binutils-2017.08) 2.27.0.20161019) #20 SMP PREEMPT Thu Nov 17 09:49:18 GMT 2022

Is this expected?

Thanks!
Jon

-- 
nvpublic

Re: [PATCH 05/15] kbuild: build init/built-in.a just once

[Masahiro Yamada]

On Thu, Nov 17, 2022 at 7:00 PM Jon Hunter <jonathanh@nvidia.com> wrote:
>
> Hi Masahiro
>
> On 28/08/2022 03:39, Masahiro Yamada wrote:
> > Kbuild builds init/built-in.a twice; first during the ordinary
> > directory descending, second from scripts/link-vmlinux.sh.
> >
> > We do this because UTS_VERSION contains the build version and the
> > timestamp. We cannot update it during the normal directory traversal
> > since we do not yet know if we need to update vmlinux. UTS_VERSION is
> > temporarily calculated, but omitted from the update check. Otherwise,
> > vmlinux would be rebuilt every time.
> >
> > When Kbuild results in running link-vmlinux.sh, it increments the
> > version number in the .version file and takes the timestamp at that
> > time to really fix UTS_VERSION.
> >
> > However, updating the same file twice is a footgun. To avoid nasty
> > timestamp issues, all build artifacts that depend on init/built-in.a
> > must be atomically generated in link-vmlinux.sh, where some of them
> > do not need rebuilding.
> >
> > To fix this issue, this commit changes as follows:
> >
> > [1] Split UTS_VERSION out to include/generated/utsversion.h from
> >      include/generated/compile.h
> >
> >      include/generated/utsversion.h is generated just before the
> >      vmlinux link. It is generated under include/generated/ because
> >      some decompressors (s390, x86) use UTS_VERSION.
> >
> > [2] Split init_uts_ns and linux_banner out to init/version-timestamp.c
> >      from init/version.c
> >
> >      init_uts_ns and linux_banner contain UTS_VERSION. During the ordinary
> >      directory descending, they are compiled with __weak and used to
> >      determine if vmlinux needs relinking. Just before the vmlinux link,
> >      they are compiled without __weak to embed the real version and
> >      timestamp.
> >
> > Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
>
>
> Since this change I have noticed that the kernel image (at least on ARM64) now contains two version strings ...
>
> $ strings arch/arm64/boot/Image | grep "Linux version"
> Linux version 6.0.0-rc7-00011-g2df8220cc511 (jonathanh@moonraker) (aarch64-linux-gnu-gcc (Linaro GCC 6.4-2017.08) 6.4.1 20170707, GNU ld (Linaro_Binutils-2017.08) 2.27.0.20161019) # SMP PREEMPT
> Linux version 6.0.0-rc7-00011-g2df8220cc511 (jonathanh@moonraker) (aarch64-linux-gnu-gcc (Linaro GCC 6.4-2017.08) 6.4.1 20170707, GNU ld (Linaro_Binutils-2017.08) 2.27.0.20161019) #20 SMP PREEMPT Thu Nov 17 09:49:18 GMT 2022
>
> Is this expected?


Yes.

The first line is a weak (i.e. unused) symbol.
The second one is a real one.


2df8220cc511326508ec4da2f43ef69311bdd7b9 fixed up
arch/powerpc/boot/wrapper because it grep's vmlinux.


The weak symbols slightly increase the image size, but
I do not know how to do this better.






> Thanks!
> Jon
>
> --
> nvpublic



-- 
Best Regards
Masahiro Yamada