path: root/Documentation/kbuild
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authorLinus Torvalds <>2019-07-12 16:03:16 -0700
committerLinus Torvalds <>2019-07-12 16:03:16 -0700
commit39ceda5ce1b002e30563fcb8ad1bb5ac8e4d59ee (patch)
tree18751f981a3a540379b9f4b01292e1b4f401aa38 /Documentation/kbuild
parent5f26f1143678d0fed8115afdcc0de99ee7cc9675 (diff)
parentd4a74bbfee03acf7bbddc77b9c9236462c744fc7 (diff)
Merge tag 'kbuild-v5.3' of git://
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:// (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/ remove unused environment variables from comments scripts/ 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 ...
Diffstat (limited to 'Documentation/kbuild')
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
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 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.
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