<feed xmlns='http://www.w3.org/2005/Atom'>
<title>user/sven/linux.git/scripts/Makefile.host, branch v5.2</title>
<subtitle>Linux Kernel
</subtitle>
<id>https://git.stealer.net/cgit.cgi/user/sven/linux.git/atom?h=v5.2</id>
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<updated>2019-05-18T02:49:57Z</updated>
<entry>
<title>kbuild: remove 'addtree' and 'flags' magic for header search paths</title>
<updated>2019-05-18T02:49:57Z</updated>
<author>
<name>Masahiro Yamada</name>
<email>yamada.masahiro@socionext.com</email>
</author>
<published>2019-05-13T06:22:17Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=cdd750bfb1f76fe9be8cfb53cbe77b2e811081ab'/>
<id>urn:sha1:cdd750bfb1f76fe9be8cfb53cbe77b2e811081ab</id>
<content type='text'>
The 'addtree' and 'flags' in scripts/Kbuild.include are so compilecated
and ugly.

As I mentioned in [1], Kbuild should stop automatic prefixing of header
search path options.

I fixed up (almost) all Makefiles in the kernel. Now 'addtree' and
'flags' have been removed.

Kbuild still caters to add $(srctree)/$(src) and $(objtree)/$(obj)
to the header search path for O= building, but never touches extra
compiler options from ccflags-y etc.

[1]: https://patchwork.kernel.org/patch/9632347/

Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
</content>
</entry>
<entry>
<title>kbuild: use $(srctree) instead of KBUILD_SRC to check out-of-tree build</title>
<updated>2019-04-02T14:28:04Z</updated>
<author>
<name>Masahiro Yamada</name>
<email>yamada.masahiro@socionext.com</email>
</author>
<published>2019-03-30T12:04:17Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=a9a49c2ad9b9b8ee20668c15ca2b806dbed8ea40'/>
<id>urn:sha1:a9a49c2ad9b9b8ee20668c15ca2b806dbed8ea40</id>
<content type='text'>
KBUILD_SRC was conventionally used for some different purposes:
 [1] To remember the source tree path
 [2] As a flag to check if sub-make is already done
 [3] As a flag to check if Kbuild runs out of tree

For [1], we do not need to remember it because the top Makefile
can compute it by $(realpath $(dir $(lastword $(MAKEFILE_LIST))))

[2] has been replaced with self-commenting 'sub_make_done'.

For [3], we can distinguish in-tree/out-of-tree by comparing
$(srctree) and '.'

This commit converts [3] to prepare for the KBUILD_SRC removal.

Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
</content>
</entry>
<entry>
<title>kbuild: skip 'addtree' and 'flags' magic for external module build</title>
<updated>2019-01-28T00:11:17Z</updated>
<author>
<name>Masahiro Yamada</name>
<email>yamada.masahiro@socionext.com</email>
</author>
<published>2019-01-16T02:56:40Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=58156ba4468f1d0de166a4330374bc9df9b74efc'/>
<id>urn:sha1:58156ba4468f1d0de166a4330374bc9df9b74efc</id>
<content type='text'>
When building an external module, $(obj) is the absolute path to it.

The header search paths from ccflags-y etc. should not be tweaked.

Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
</content>
</entry>
<entry>
<title>kbuild: Rename HOST_LOADLIBES to KBUILD_HOSTLDLIBS</title>
<updated>2018-07-17T16:18:05Z</updated>
<author>
<name>Laura Abbott</name>
<email>labbott@redhat.com</email>
</author>
<published>2018-07-10T00:46:01Z</published>
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<id>urn:sha1:8377bd2b9ee1be35b39b5523f640a2b75ddd7c4e</id>
<content type='text'>
In preparation for enabling command line LDLIBS, re-name HOST_LOADLIBES
to KBUILD_HOSTLDLIBS as the internal use only flags. Also rename
existing usage to HOSTLDLIBS for consistency. This should not have any
visible effects.

Signed-off-by: Laura Abbott &lt;labbott@redhat.com&gt;
Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
</content>
</entry>
<entry>
<title>kbuild: Rename HOSTLDFLAGS to KBUILD_HOSTLDFLAGS</title>
<updated>2018-07-17T16:18:05Z</updated>
<author>
<name>Laura Abbott</name>
<email>labbott@redhat.com</email>
</author>
<published>2018-07-10T00:46:00Z</published>
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<id>urn:sha1:b90a368000abe5e015e0b045ca2ff7c2173b94c0</id>
<content type='text'>
In preparation for enabling command line LDFLAGS, re-name HOSTLDFLAGS
to KBUILD_HOSTLDFLAGS as the internal use only flags. This should not
have any visible effects.

Signed-off-by: Laura Abbott &lt;labbott@redhat.com&gt;
Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
</content>
</entry>
<entry>
<title>kbuild: Rename HOSTCXXFLAGS to KBUILD_HOSTCXXFLAGS</title>
<updated>2018-07-17T16:18:05Z</updated>
<author>
<name>Laura Abbott</name>
<email>labbott@redhat.com</email>
</author>
<published>2018-07-10T00:45:59Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=10844aebf44851a981ddaa714351ae61c4b29103'/>
<id>urn:sha1:10844aebf44851a981ddaa714351ae61c4b29103</id>
<content type='text'>
In preparation for enabling command line CXXFLAGS, re-name HOSTCXXFLAGS
to KBUILD_HOSTCXXFLAGS as the internal use only flags. This should not
have any visible effects.

Signed-off-by: Laura Abbott &lt;labbott@redhat.com&gt;
Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
</content>
</entry>
<entry>
<title>kbuild: Rename HOSTCFLAGS to KBUILD_HOSTCFLAGS</title>
<updated>2018-07-17T16:18:05Z</updated>
<author>
<name>Laura Abbott</name>
<email>labbott@redhat.com</email>
</author>
<published>2018-07-10T00:45:58Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=96f14fe738b69dd97a33efe3cc8ab330af5fd1f1'/>
<id>urn:sha1:96f14fe738b69dd97a33efe3cc8ab330af5fd1f1</id>
<content type='text'>
In preparation for enabling command line CFLAGS, re-name HOSTCFLAGS to
KBUILD_HOSTCFLAGS as the internal use only flags. This should not have
any visible effects.

Signed-off-by: Laura Abbott &lt;labbott@redhat.com&gt;
Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
</content>
</entry>
<entry>
<title>kbuild: use HOSTLDFLAGS for single .c executables</title>
<updated>2018-04-07T10:04:02Z</updated>
<author>
<name>Robin Jarry</name>
<email>robin.jarry@6wind.com</email>
</author>
<published>2018-02-26T18:41:47Z</published>
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<id>urn:sha1:63185b46cdb36905d585c73cc4730fec44cdf55d</id>
<content type='text'>
When compiling executables from a single .c file, the linker is also
invoked. Pass the HOSTLDFLAGS like for other linker commands.

Signed-off-by: Robin Jarry &lt;robin.jarry@6wind.com&gt;
Cc: Josh Poimboeuf &lt;jpoimboe@redhat.com&gt;
Cc: Ingo Molnar &lt;mingo@kernel.org&gt;
Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
</content>
</entry>
<entry>
<title>Merge tag 'kbuild-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild</title>
<updated>2017-11-18T01:45:29Z</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2017-11-18T01:45:29Z</published>
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<id>urn:sha1:09bd7c75e55cbaa6c731b0c3a5512ad89159f26f</id>
<content type='text'>
Pull Kbuild updates from Masahiro Yamada:
 "One of the most remarkable improvements in this cycle is, Kbuild is
  now able to cache the result of shell commands. Some variables are
  expensive to compute, for example, $(call cc-option,...) invokes the
  compiler. It is not efficient to redo this computation every time,
  even when we are not actually building anything. Kbuild creates a
  hidden file ".cache.mk" that contains invoked shell commands and their
  results. The speed-up should be noticeable.

  Summary:

   - Fix arch build issues (hexagon, sh)

   - Clean up various Makefiles and scripts

   - Fix wrong usage of {CFLAGS,LDFLAGS}_MODULE in arch Makefiles

   - Cache variables that are expensive to compute

   - Improve cc-ldopton and ld-option for Clang

   - Optimize output directory creation"

* tag 'kbuild-v4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (30 commits)
  kbuild: move coccicheck help from scripts/Makefile.help to top Makefile
  sh: decompressor: add shipped files to .gitignore
  frv: .gitignore: ignore vmlinux.lds
  selinux: remove unnecessary assignment to subdir-
  kbuild: specify FORCE in Makefile.headersinst as .PHONY target
  kbuild: remove redundant mkdir from ./Kbuild
  kbuild: optimize object directory creation for incremental build
  kbuild: create object directories simpler and faster
  kbuild: filter-out PHONY targets from "targets"
  kbuild: remove redundant $(wildcard ...) for cmd_files calculation
  kbuild: create directory for make cache only when necessary
  sh: select KBUILD_DEFCONFIG depending on ARCH
  kbuild: fix linker feature test macros when cross compiling with Clang
  kbuild: shrink .cache.mk when it exceeds 1000 lines
  kbuild: do not call cc-option before KBUILD_CFLAGS initialization
  kbuild: Cache a few more calls to the compiler
  kbuild: Add a cache for generated variables
  kbuild: add forward declaration of default target to Makefile.asm-generic
  kbuild: remove KBUILD_SUBDIR_ASFLAGS and KBUILD_SUBDIR_CCFLAGS
  hexagon/kbuild: replace CFLAGS_MODULE with KBUILD_CFLAGS_MODULE
  ...
</content>
</entry>
<entry>
<title>kbuild: create object directories simpler and faster</title>
<updated>2017-11-16T00:07:35Z</updated>
<author>
<name>Masahiro Yamada</name>
<email>yamada.masahiro@socionext.com</email>
</author>
<published>2017-11-13T10:29:37Z</published>
<link rel='alternate' type='text/html' href='https://git.stealer.net/cgit.cgi/user/sven/linux.git/commit/?id=8a78756eb545a6fb8007fa154a626ca2bc208027'/>
<id>urn:sha1:8a78756eb545a6fb8007fa154a626ca2bc208027</id>
<content type='text'>
For the out-of-tree build, scripts/Makefile.build creates output
directories, but this operation is not efficient.

scripts/Makefile.lib calculates obj-dirs as follows:

  obj-dirs := $(dir $(multi-objs) $(obj-y))

Please notice $(sort ...) is not used here.  Usually the result is
as many "./" as objects here.

For a lot of duplicated paths, the following command is invoked.

  _dummy := $(foreach d,$(obj-dirs), $(shell [ -d $(d) ] || mkdir -p $(d)))

Then, the costly shell command is run over and over again.

I see many points for optimization:

[1] Use $(sort ...) to cut down duplicated paths before passing them
    to system call
[2] Use single $(shell ...) instead of repeating it with $(foreach ...)
    This will reduce forking.
[3] We can calculate obj-dirs more simply.  Most of objects are already
    accumulated in $(targets).  So, $(dir $(targets)) is fine and more
    comprehensive.

I also removed ugly code in arch/x86/entry/vdso/Makefile.  This is now
really unnecessary.

Signed-off-by: Masahiro Yamada &lt;yamada.masahiro@socionext.com&gt;
Acked-by: Ingo Molnar &lt;mingo@kernel.org&gt;
Tested-by: Douglas Anderson &lt;dianders@chromium.org&gt;
</content>
</entry>
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