Merge tag 'kbuild-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - remove headers_{install,check}_all targets

 - remove unreasonable 'depends on !UML' from CONFIG_SAMPLES

 - re-implement 'make headers_install' more cleanly

 - add new header-test-y syntax to compile-test headers

 - compile-test exported headers to ensure they are compilable in
   user-space

 - compile-test headers under include/ to ensure they are self-contained

 - remove -Waggregate-return, -Wno-uninitialized, -Wno-unused-value
   flags

 - add -Werror=unknown-warning-option for Clang

 - add 128-bit built-in types support to genksyms

 - fix missed rebuild of modules.builtin

 - propagate 'No space left on device' error in fixdep to Make

 - allow Clang to use its integrated assembler

 - improve some coccinelle scripts

 - add a new flag KBUILD_ABS_SRCTREE to request Kbuild to use absolute
   path for $(srctree).

 - do not ignore errors when compression utility is missing

 - misc cleanups

* tag 'kbuild-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (49 commits)
  kbuild: use -- separater intead of $(filter-out ...) for cc-cross-prefix
  kbuild: Inform user to pass ARCH= for make mrproper
  kbuild: fix compression errors getting ignored
  kbuild: add a flag to force absolute path for srctree
  kbuild: replace KBUILD_SRCTREE with boolean building_out_of_srctree
  kbuild: remove src and obj from the top Makefile
  scripts/tags.sh: remove unused environment variables from comments
  scripts/tags.sh: drop SUBARCH support for ARM
  kbuild: compile-test kernel headers to ensure they are self-contained
  kheaders: include only headers into kheaders_data.tar.xz
  kheaders: remove meaningless -R option of 'ls'
  kbuild: support header-test-pattern-y
  kbuild: do not create wrappers for header-test-y
  kbuild: compile-test exported headers to ensure they are self-contained
  init/Kconfig: add CONFIG_CC_CAN_LINK
  kallsyms: exclude kasan local symbols on s390
  kbuild: add more hints about SUBDIRS replacement
  coccinelle: api/stream_open: treat all wait_.*() calls as blocking
  coccinelle: put_device: Add a cast to an expression for an assignment
  coccinelle: put_device: Adjust a message construction
  ...

3 files changed, 26 insertions, 12 deletions

diff --git a/Documentation/kbuild/headers_install.rst b/Documentation/kbuild/headers_install.rst
index 1ab7294e41ac..f6c6b74a609c 100644
--- a/Documentation/kbuild/headers_install.rst
+++ b/Documentation/kbuild/headers_install.rst
@@ -40,12 +40,5 @@ INSTALL_HDR_PATH indicates where to install the headers. It defaults to
 An 'include' directory is automatically created inside INSTALL_HDR_PATH and
 headers are installed in 'INSTALL_HDR_PATH/include'.
 
-The command "make headers_install_all" exports headers for all architectures
-simultaneously.  (This is mostly of interest to distribution maintainers,
-who create an architecture-independent tarball from the resulting include
-directory.)  You also can use HDR_ARCH_LIST to specify list of architectures.
-Remember to provide the appropriate linux/asm directory via "mv" or "ln -s"
-before building a C library with headers exported this way.
-
 The kernel header export infrastructure is maintained by David Woodhouse
 <dwmw2@infradead.org>.
diff --git a/Documentation/kbuild/kbuild.rst b/Documentation/kbuild/kbuild.rst
index e774e760522d..b25548963d70 100644
--- a/Documentation/kbuild/kbuild.rst
+++ b/Documentation/kbuild/kbuild.rst
@@ -200,6 +200,15 @@ The output directory is often set using "O=..." on the commandline.
 
 The value can be overridden in which case the default value is ignored.
 
+KBUILD_ABS_SRCTREE
+--------------------------------------------------
+Kbuild uses a relative path to point to the tree when possible. For instance,
+when building in the source tree, the source tree path is '.'
+
+Setting this flag requests Kbuild to use absolute path to the source tree.
+There are some useful cases to do so, like when generating tag files with
+absolute path entries etc.
+
 KBUILD_SIGN_PIN
 ---------------
 This variable allows a passphrase or PIN to be passed to the sign-file
diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
index 9274cdcc9bd2..093f2d79ab95 100644
--- a/Documentation/kbuild/makefiles.rst
+++ b/Documentation/kbuild/makefiles.rst
@@ -999,11 +999,7 @@ When kbuild executes, the following steps are followed (roughly):
 ------------------------------------
 
 	The archheaders: rule is used to generate header files that
-	may be installed into user space by "make header_install" or
-	"make headers_install_all".  In order to support
-	"make headers_install_all", this target has to be able to run
-	on an unconfigured tree, or a tree configured for another
-	architecture.
+	may be installed into user space by "make header_install".
 
 	It is run before "make archprepare" when run on the
 	architecture itself.
@@ -1140,6 +1136,22 @@ When kbuild executes, the following steps are followed (roughly):
 	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.a.
 
+    header-test-y
+
+	header-test-y specifies headers (*.h) in the current directory that
+	should be compile tested to ensure they are self-contained,
+	i.e. compilable as standalone units. If CONFIG_HEADER_TEST is enabled,
+	this builds them as part of extra-y.
+
+    header-test-pattern-y
+
+	This works as a weaker version of header-test-y, and accepts wildcard
+	patterns. The typical usage is:
+
+		  header-test-pattern-y += *.h
+
+	This specifies all the files that matches to '*.h' in the current
+	directory, but the files in 'header-test-' are excluded.
 
 6.7 Commands useful for building a boot image
 ---------------------------------------------