Merge tag 'kbuild-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Add generic support for built-in boot DTB files

 - Enable TAB cycling for dialog buttons in nconfig

 - Fix issues in streamline_config.pl

 - Refactor Kconfig

 - Add support for Clang's AutoFDO (Automatic Feedback-Directed
   Optimization)

 - Add support for Clang's Propeller, a profile-guided optimization.

 - Change the working directory to the external module directory for M=
   builds

 - Support building external modules in a separate output directory

 - Enable objtool for *.mod.o and additional kernel objects

 - Use lz4 instead of deprecated lz4c

 - Work around a performance issue with "git describe"

 - Refactor modpost

* tag 'kbuild-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (85 commits)
  kbuild: rename .tmp_vmlinux.kallsyms0.syms to .tmp_vmlinux0.syms
  gitignore: Don't ignore 'tags' directory
  kbuild: add dependency from vmlinux to resolve_btfids
  modpost: replace tdb_hash() with hash_str()
  kbuild: deb-pkg: add python3:native to build dependency
  genksyms: reduce indentation in export_symbol()
  modpost: improve error messages in device_id_check()
  modpost: rename alias symbol for MODULE_DEVICE_TABLE()
  modpost: rename variables in handle_moddevtable()
  modpost: move strstarts() to modpost.h
  modpost: convert do_usb_table() to a generic handler
  modpost: convert do_of_table() to a generic handler
  modpost: convert do_pnp_device_entry() to a generic handler
  modpost: convert do_pnp_card_entries() to a generic handler
  modpost: call module_alias_printf() from all do_*_entry() functions
  modpost: pass (struct module *) to do_*_entry() functions
  modpost: remove DEF_FIELD_ADDR_VAR() macro
  modpost: deduplicate MODULE_ALIAS() for all drivers
  modpost: introduce module_alias_printf() helper
  modpost: remove unnecessary check in do_acpi_entry()
  ...

4 files changed, 51 insertions, 4 deletions

diff --git a/Documentation/kbuild/kbuild.rst b/Documentation/kbuild/kbuild.rst
index 1796b3eba37b..17c9f920f03d 100644
--- a/Documentation/kbuild/kbuild.rst
+++ b/Documentation/kbuild/kbuild.rst
@@ -137,12 +137,18 @@ Specify the output directory when building the kernel.
 This variable can also be used to point to the kernel output directory when
 building external modules against a pre-built kernel in a separate build
 directory. Please note that this does NOT specify the output directory for the
-external modules themselves.
+external modules themselves. (Use KBUILD_EXTMOD_OUTPUT for that purpose.)
 
 The output directory can also be specified using "O=...".
 
 Setting "O=..." takes precedence over KBUILD_OUTPUT.
 
+KBUILD_EXTMOD_OUTPUT
+--------------------
+Specify the output directory for external modules.
+
+Setting "MO=..." takes precedence over KBUILD_EXTMOD_OUTPUT.
+
 KBUILD_EXTRA_WARN
 -----------------
 Specify the extra build checks. The same value can be assigned by passing
diff --git a/Documentation/kbuild/kconfig-language.rst b/Documentation/kbuild/kconfig-language.rst
index 43037be96a16..2619fdf56e68 100644
--- a/Documentation/kbuild/kconfig-language.rst
+++ b/Documentation/kbuild/kconfig-language.rst
@@ -412,8 +412,8 @@ choices::
 	<choice block>
 	"endchoice"
 
-This defines a choice group and accepts any of the above attributes as
-options.
+This defines a choice group and accepts "prompt", "default", "depends on", and
+"help" attributes as options.
 
 A choice only allows a single config entry to be selected.
 
diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
index 7964e0c245ae..d36519f194dc 100644
--- a/Documentation/kbuild/makefiles.rst
+++ b/Documentation/kbuild/makefiles.rst
@@ -449,6 +449,20 @@ $(obj)
   to prerequisites are referenced with $(src) (because they are not
   generated files).
 
+$(srcroot)
+  $(srcroot) refers to the root of the source you are building, which can be
+  either the kernel source or the external modules source, depending on whether
+  KBUILD_EXTMOD is set. This can be either a relative or an absolute path, but
+  if KBUILD_ABS_SRCTREE=1 is set, it is always an absolute path.
+
+$(srctree)
+  $(srctree) refers to the root of the kernel source tree. When building the
+  kernel, this is the same as $(srcroot).
+
+$(objtree)
+  $(objtree) refers to the root of the kernel object tree. It is ``.`` when
+  building the kernel, but it is different when building external modules.
+
 $(kecho)
   echoing information to user in a rule is often a good practice
   but when execution ``make -s`` one does not expect to see any output
diff --git a/Documentation/kbuild/modules.rst b/Documentation/kbuild/modules.rst
index cd5a54d91e6d..101de236cd0c 100644
--- a/Documentation/kbuild/modules.rst
+++ b/Documentation/kbuild/modules.rst
@@ -59,6 +59,12 @@ Command Syntax
 
 		$ make -C /lib/modules/`uname -r`/build M=$PWD modules_install
 
+	Starting from Linux 6.13, you can use the -f option instead of -C. This
+	will avoid unnecessary change of the working directory. The external
+	module will be output to the directory where you invoke make.
+
+		$ make -f /lib/modules/`uname -r`/build/Makefile M=$PWD
+
 Options
 -------
 
@@ -66,7 +72,10 @@ Options
 	of the kernel output directory if the kernel was built in a separate
 	build directory.)
 
-	make -C $KDIR M=$PWD
+	You can optionally pass MO= option if you want to build the modules in
+	a separate directory.
+
+	make -C $KDIR M=$PWD [MO=$BUILD_DIR]
 
 	-C $KDIR
 		The directory that contains the kernel and relevant build
@@ -80,6 +89,9 @@ Options
 		directory where the external module (kbuild file) is
 		located.
 
+	MO=$BUILD_DIR
+		Specifies a separate output directory for the external module.
+
 Targets
 -------
 
@@ -215,6 +227,21 @@ Separate Kbuild File and Makefile
 	consisting of several hundred lines, and here it really pays
 	off to separate the kbuild part from the rest.
 
+	Linux 6.13 and later support another way. The external module Makefile
+	can include the kernel Makefile directly, rather than invoking sub Make.
+
+	Example 3::
+
+		--> filename: Kbuild
+		obj-m  := 8123.o
+		8123-y := 8123_if.o 8123_pci.o
+
+		--> filename: Makefile
+		KDIR ?= /lib/modules/$(shell uname -r)/build
+		export KBUILD_EXTMOD := $(realpath $(dir $(lastword $(MAKEFILE_LIST))))
+		include $(KDIR)/Makefile
+
+
 Building Multiple Modules
 -------------------------