Merge tag 'kbuild-v4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - add a shell script to get Clang version

 - improve portability of build scripts

 - drop always-enabled CONFIG_THIN_ARCHIVE and remove unused code

 - rename built-in.o which is now thin archive to built-in.a

 - process clean/build targets one by one to get along with -j option

 - simplify ld-option

 - improve building with CONFIG_TRIM_UNUSED_KSYMS

 - define KBUILD_MODNAME even for objects shared among multiple modules

 - avoid linking multiple instances of same objects from composite
   objects

 - move <linux/compiler_types.h> to c_flags to include it only for C
   files

 - clean-up various Makefiles

* tag 'kbuild-v4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (29 commits)
  kbuild: get <linux/compiler_types.h> out of <linux/kconfig.h>
  kbuild: clean up link rule of composite modules
  kbuild: clean up archive rule of built-in.a
  kbuild: remove partial section mismatch detection for built-in.a
  net: liquidio: clean up Makefile for simpler composite object handling
  lib: zstd: clean up Makefile for simpler composite object handling
  kbuild: link $(real-obj-y) instead of $(obj-y) into built-in.a
  kbuild: rename real-objs-y/m to real-obj-y/m
  kbuild: move modname and modname-multi close to modname_flags
  kbuild: simplify modname calculation
  kbuild: fix modname for composite modules
  kbuild: define KBUILD_MODNAME even if multiple modules share objects
  kbuild: remove unnecessary $(subst $(obj)/, , ...) in modname-multi
  kbuild: Use ls(1) instead of stat(1) to obtain file size
  kbuild: link vmlinux only once for CONFIG_TRIM_UNUSED_KSYMS
  kbuild: move include/config/ksym/* to include/ksym/*
  kbuild: move CONFIG_TRIM_UNUSED_KSYMS code unneeded for external module
  kbuild: restore autoksyms.h touch to the top Makefile
  kbuild: move 'scripts' target below
  kbuild: remove wrong 'touch' in adjust_autoksyms.sh
  ...

3 files changed, 15 insertions, 19 deletions

diff --git a/Documentation/kbuild/kbuild.txt b/Documentation/kbuild/kbuild.txt
index ac2363ea05c5..6c9c69ec3986 100644
--- a/Documentation/kbuild/kbuild.txt
+++ b/Documentation/kbuild/kbuild.txt
@@ -50,10 +50,6 @@ LDFLAGS_MODULE
 --------------------------------------------------
 Additional options used for $(LD) when linking modules.
 
-LDFLAGS_vmlinux
---------------------------------------------------
-Additional options passed to final link of vmlinux.
-
 KBUILD_VERBOSE
 --------------------------------------------------
 Set the kbuild verbosity. Can be assigned same values as "V=...".
diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
index 71e9feefb63c..048fc39a6b91 100644
--- a/Documentation/kbuild/makefiles.txt
+++ b/Documentation/kbuild/makefiles.txt
@@ -153,12 +153,18 @@ more details, with real examples.
 	configuration.
 
 	Kbuild compiles all the $(obj-y) files.  It then calls
-	"$(LD) -r" to merge these files into one built-in.o file.
-	built-in.o is later linked into vmlinux by the parent Makefile.
+	"$(AR) rcSTP" to merge these files into one built-in.a file.
+	This is a thin archive without a symbol table, which makes it
+	unsuitable as a linker input.
+
+	The scripts/link-vmlinux.sh script later makes an aggregate
+	built-in.a with "${AR} rcsTP", which creates the thin archive
+	with a symbol table and an index, making it a valid input for
+	the final vmlinux link passes.
 
 	The order of files in $(obj-y) is significant.  Duplicates in
 	the lists are allowed: the first instance will be linked into
-	built-in.o and succeeding instances will be ignored.
+	built-in.a and succeeding instances will be ignored.
 
 	Link order is significant, because certain functions
 	(module_init() / __initcall) will be called during boot in the
@@ -222,7 +228,7 @@ more details, with real examples.
 	Note: Of course, when you are building objects into the kernel,
 	the syntax above will also work. So, if you have CONFIG_EXT2_FS=y,
 	kbuild will build an ext2.o file for you out of the individual
-	parts and then link this into built-in.o, as you would expect.
+	parts and then link this into built-in.a, as you would expect.
 
 --- 3.4 Objects which export symbols
 
@@ -232,7 +238,7 @@ more details, with real examples.
 --- 3.5 Library file goals - lib-y
 
 	Objects listed with obj-* are used for modules, or
-	combined in a built-in.o for that specific directory.
+	combined in a built-in.a for that specific directory.
 	There is also the possibility to list objects that will
 	be included in a library, lib.a.
 	All objects listed with lib-y are combined in a single
@@ -244,7 +250,7 @@ more details, with real examples.
 
 	Note that the same kbuild makefile may list files to be built-in
 	and to be part of a library. Therefore the same directory
-	may contain both a built-in.o and a lib.a file.
+	may contain both a built-in.a and a lib.a file.
 
 	Example:
 		#arch/x86/lib/Makefile
@@ -831,12 +837,6 @@ When kbuild executes, the following steps are followed (roughly):
 	Note: ldflags-y can be used to further customise
 	the flags used. See chapter 3.7.
 
-    LDFLAGS_MODULE	Options for $(LD) when linking modules
-
-	LDFLAGS_MODULE is used to set specific flags for $(LD) when
-	linking the .ko files used for modules.
-	Default is "-r", for relocatable output.
-
     LDFLAGS_vmlinux	Options for $(LD) when linking vmlinux
 
 	LDFLAGS_vmlinux is used to specify additional flags to pass to
@@ -986,7 +986,7 @@ When kbuild executes, the following steps are followed (roughly):
 
 	$(head-y) lists objects to be linked first in vmlinux.
 	$(libs-y) lists directories where a lib.a archive can be located.
-	The rest list directories where a built-in.o object file can be
+	The rest list directories where a built-in.a object file can be
 	located.
 
 	$(init-y) objects will be located after $(head-y).
@@ -1071,7 +1071,7 @@ When kbuild executes, the following steps are followed (roughly):
 		extra-y := head.o init_task.o
 
 	In this example, extra-y is used to list object files that
-	shall be built, but shall not be linked as part of built-in.o.
+	shall be built, but shall not be linked as part of built-in.a.
 
 
 --- 6.7 Commands useful for building a boot image
diff --git a/Documentation/process/changes.rst b/Documentation/process/changes.rst
index 5470f1b74375..ddc029734b25 100644
--- a/Documentation/process/changes.rst
+++ b/Documentation/process/changes.rst
@@ -78,7 +78,7 @@ Binutils
 --------
 
 The build system has, as of 4.13, switched to using thin archives (`ar T`)
-rather than incremental linking (`ld -r`) for built-in.o intermediate steps.
+rather than incremental linking (`ld -r`) for built-in.a intermediate steps.
 This requires binutils 2.20 or newer.
 
 Flex