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authorLinus Torvalds <torvalds@linux-foundation.org>2019-12-21 10:49:47 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-12-21 10:49:47 -0800
commit6c1c79a5f4eead27465d4d1d97ce230163772a78 (patch)
tree1c98d567a10f9d7a91db14d2b8f56795e10416b5 /Documentation
parent6210469417fd967ec72dea56723593beefeecafb (diff)
parent28f94a44298c99c0db85539874b62f21d94fcaa7 (diff)
Merge tag 'kbuild-fixes-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild fixes from Masahiro Yamada: - fix warning in out-of-tree 'make clean' - add READELF variable to the top Makefile - fix broken builds when LINUX_COMPILE_BY contains a backslash - fix build warning in kallsyms - fix NULL pointer access in expr_eq() in Kconfig - fix missing dependency on rsync in deb-pkg build - remove ---help--- from documentation - fix misleading documentation about directory descending * tag 'kbuild-fixes-v5.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: kbuild: clarify the difference between obj-y and obj-m w.r.t. descending kconfig: remove ---help--- from documentation scripts: package: mkdebian: add missing rsync dependency kconfig: don't crash on NULL expressions in expr_eq() scripts/kallsyms: fix offset overflow of kallsyms_relative_base mkcompile_h: use printf for LINUX_COMPILE_BY mkcompile_h: git rid of UTS_TRUNCATE from LINUX_COMPILE_{BY,HOST} x86/boot: kbuild: allow readelf executable to be specified kbuild: fix 'No such file or directory' warning when cleaning
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/kbuild/kconfig-language.rst5
-rw-r--r--Documentation/kbuild/makefiles.rst16
2 files changed, 14 insertions, 7 deletions
diff --git a/Documentation/kbuild/kconfig-language.rst b/Documentation/kbuild/kconfig-language.rst
index 74bef19f69f0..231e6a64957f 100644
--- a/Documentation/kbuild/kconfig-language.rst
+++ b/Documentation/kbuild/kconfig-language.rst
@@ -196,14 +196,11 @@ applicable everywhere (see syntax).
or equal to the first symbol and smaller than or equal to the second
symbol.
-- help text: "help" or "---help---"
+- help text: "help"
This defines a help text. The end of the help text is determined by
the indentation level, this means it ends at the first line which has
a smaller indentation than the first line of the help text.
- "---help---" and "help" do not differ in behaviour, "---help---" is
- used to help visually separate configuration logic from help within
- the file as an aid to developers.
- misc options: "option" <symbol>[=<value>]
diff --git a/Documentation/kbuild/makefiles.rst b/Documentation/kbuild/makefiles.rst
index b9b50553bfc5..d7e6534a8505 100644
--- a/Documentation/kbuild/makefiles.rst
+++ b/Documentation/kbuild/makefiles.rst
@@ -297,9 +297,19 @@ more details, with real examples.
If CONFIG_EXT2_FS is set to either 'y' (built-in) or 'm' (modular)
the corresponding obj- variable will be set, and kbuild will descend
down in the ext2 directory.
- Kbuild only uses this information to decide that it needs to visit
- the directory, it is the Makefile in the subdirectory that
- specifies what is modular and what is built-in.
+
+ Kbuild uses this information not only to decide that it needs to visit
+ the directory, but also to decide whether or not to link objects from
+ the directory into vmlinux.
+
+ When Kbuild descends into the directory with 'y', all built-in objects
+ from that directory are combined into the built-in.a, which will be
+ eventually linked into vmlinux.
+
+ When Kbuild descends into the directory with 'm', in contrast, nothing
+ from that directory will be linked into vmlinux. If the Makefile in
+ that directory specifies obj-y, those objects will be left orphan.
+ It is very likely a bug of the Makefile or of dependencies in Kconfig.
It is good practice to use a `CONFIG_` variable when assigning directory
names. This allows kbuild to totally skip the directory if the