Commit Graph

21 Commits

Author SHA1 Message Date
Masahiro Yamada c83f020973 kconfig: remove named choice support
Commit 5a1aa8a1af ("kconfig: add named choice group") did not provide
enough explanation regarding its benefits. A use case was found in
another project [1] sometime later, this feature has never been used in
the kernel.

[1]: https://lore.kernel.org/all/201012150034.01356.yann.morin.1998@anciens.enib.fr/

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2024-03-10 13:29:48 +09:00
Arnd Bergmann 28d49e1716 Documentation: kbuild: explain handling optional dependencies
This problem frequently comes up in randconfig testing, with
drivers failing to link because of a dependency on an optional
feature.

The Kconfig language for this is very confusing, so try to
document it in "Kconfig hints" section.

Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2023-09-25 16:01:05 +09:00
Nick Desaulniers a0a12c3ed0 asm goto: eradicate CC_HAS_ASM_GOTO
GCC has supported asm goto since 4.5, and Clang has since version 9.0.0.
The minimum supported versions of these tools for the build according to
Documentation/process/changes.rst are 5.1 and 11.0.0 respectively.

Remove the feature detection script, Kconfig option, and clean up some
fallback code that is no longer supported.

The removed script was also testing for a GCC specific bug that was
fixed in the 4.7 release.

Also remove workarounds for bpftrace using clang older than 9.0.0, since
other BPF backend fixes are required at this point.

Link: https://lore.kernel.org/lkml/CAK7LNATSr=BXKfkdW8f-H5VT_w=xBpT2ZQcZ7rm6JfkdE+QnmA@mail.gmail.com/
Link: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48637
Acked-by: Borislav Petkov <bp@suse.de>
Suggested-by: Masahiro Yamada <masahiroy@kernel.org>
Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-08-21 10:06:28 -07:00
Baruch Siach 59316eac0e docs: kbuild: fix typo
on -> one.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-07-27 21:18:00 +09:00
Necip Fazil Yildiran cab802b7b8 docs: kbuild: add references on Kconfig semantics
Add references to 1) a research paper which provides a definition of
Kconfig semantics, 2) the kismet tool, which checks for unmet direct
dependency bugs in Kconfig specifications.

Signed-off-by: Paul Gazzillo <paul@pgazz.com>
Signed-off-by: Necip Fazil Yildiran <fazilyildiran@gmail.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-04-06 19:27:41 +09:00
Miguel Ojeda c199d5d0a7 doc: kbuild: fix default in `imply` table
`BAZ` takes `FOO`'s value as default (as far as `BAR` allows it).

Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-01-08 18:28:21 +09:00
Masahiro Yamada 6dd85ff178 kconfig: change "modules" from sub-option to first-level attribute
Now "modules" is the only member of the "option" property.

Remove "option", and move "modules" to the top level property.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-14 15:22:49 +09:00
Masahiro Yamada ab838577aa kconfig: remove allnoconfig_y option
Now that the only user, CONFIG_EMBEDDED has stopped using this option,
remove it entirely.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-14 15:22:49 +09:00
Masahiro Yamada b75b0a819a kconfig: change defconfig_list option to environment variable
"defconfig_list" is a weird option that defines a static symbol that
declares the list of base config files in case the .config does not
exist yet.

This is quite different from other normal symbols; we just abused the
"string" type and the "default" properties to list out the input files.
They must be fixed values since these are searched for and loaded in
the parse stage.

It is an ugly hack, and should not exist in the first place. Providing
this feature as an environment variable is a saner approach.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-14 15:22:48 +09:00
Geert Uytterhoeven 18084e435f Documentation/kbuild: Document platform dependency practises
Document best practises for using architecture and platform dependencies.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21 13:57:08 +09:00
Geert Uytterhoeven c613583b6a Documentation/kbuild: Document COMPILE_TEST dependencies
Document best practises for using COMPILE_TEST dependencies.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-12-21 13:57:08 +09:00
Linus Torvalds fc80c51fd4 Kbuild updates for v5.9
- run the checker (e.g. sparse) after the compiler
 
  - remove unneeded cc-option tests for old compiler flags
 
  - fix tar-pkg to install dtbs
 
  - introduce ccflags-remove-y and asflags-remove-y syntax
 
  - allow to trace functions in sub-directories of lib/
 
  - introduce hostprogs-always-y and userprogs-always-y syntax
 
  - various Makefile cleanups
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Merge tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - run the checker (e.g. sparse) after the compiler

 - remove unneeded cc-option tests for old compiler flags

 - fix tar-pkg to install dtbs

 - introduce ccflags-remove-y and asflags-remove-y syntax

 - allow to trace functions in sub-directories of lib/

 - introduce hostprogs-always-y and userprogs-always-y syntax

 - various Makefile cleanups

* tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: stop filtering out $(GCC_PLUGINS_CFLAGS) from cc-option base
  kbuild: include scripts/Makefile.* only when relevant CONFIG is enabled
  kbuild: introduce hostprogs-always-y and userprogs-always-y
  kbuild: sort hostprogs before passing it to ifneq
  kbuild: move host .so build rules to scripts/gcc-plugins/Makefile
  kbuild: Replace HTTP links with HTTPS ones
  kbuild: trace functions in subdirectories of lib/
  kbuild: introduce ccflags-remove-y and asflags-remove-y
  kbuild: do not export LDFLAGS_vmlinux
  kbuild: always create directories of targets
  powerpc/boot: add DTB to 'targets'
  kbuild: buildtar: add dtbs support
  kbuild: remove cc-option test of -ffreestanding
  kbuild: remove cc-option test of -fno-stack-protector
  Revert "kbuild: Create directory for target DTB"
  kbuild: run the checker after the compiler
2020-08-09 14:10:26 -07:00
Alexander A. Klimov 16a122c743 kbuild: Replace HTTP links with HTTPS ones
Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.

Deterministic algorithm:
For each file:
  If not .svg:
    For each line:
      If doesn't contain `\bxmlns\b`:
        For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
	  If neither `\bgnu\.org/license`, nor `\bmozilla\.org/MPL\b`:
            If both the HTTP and HTTPS versions
            return 200 OK and serve the same content:
              Replace HTTP with HTTPS.

Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-08-10 01:32:59 +09:00
Randy Dunlap 14bee1674a Documentation: kbuild/kconfig-language: eliminate duplicated word
Drop the doubled word "the".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Masahiro Yamada <masahiroy@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michal Marek <michal.lkml@markovi.net>
Cc: linux-kbuild@vger.kernel.org
Link: https://lore.kernel.org/r/20200707180414.10467-11-rdunlap@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-07-13 09:44:06 -06:00
Masahiro Yamada 893ab00439 kbuild: remove cc-option test of -fno-stack-protector
Some Makefiles already pass -fno-stack-protector unconditionally.
For example, arch/arm64/kernel/vdso/Makefile, arch/x86/xen/Makefile.

No problem report so far about hard-coding this option. So, we can
assume all supported compilers know -fno-stack-protector.

GCC 4.8 and Clang support this option (https://godbolt.org/z/_HDGzN)

Get rid of cc-option from -fno-stack-protector.

Remove CONFIG_CC_HAS_STACKPROTECTOR_NONE, which is always 'y'.

Note:
arch/mips/vdso/Makefile adds -fno-stack-protector twice, first
unconditionally, and second conditionally. I removed the second one.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2020-07-07 11:13:10 +09:00
Masahiro Yamada 3a9dd3ecb2 kconfig: make 'imply' obey the direct dependency
The 'imply' statement may create unmet direct dependency when the
implied symbol depends on m.

[Test Code]

  config FOO
          tristate "foo"
          imply BAZ

  config BAZ
          tristate "baz"
          depends on BAR

  config BAR
          def_tristate m

  config MODULES
          def_bool y
          option modules

If you set FOO=y, BAZ is also promoted to y, which results in the
following .config file:

  CONFIG_FOO=y
  CONFIG_BAZ=y
  CONFIG_BAR=m
  CONFIG_MODULES=y

This does not meet the dependency 'BAZ depends on BAR'.

Unlike 'select', what is worse, Kconfig never shows the
'WARNING: unmet direct dependencies detected for ...' for this case.

Because 'imply' is considered to be weaker than 'depends on', Kconfig
should take the direct dependency into account.

For clarification, describe this case in kconfig-language.rst too.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
2020-03-13 10:05:34 +09:00
Masahiro Yamada def2fbffe6 kconfig: allow symbols implied by y to become m
The 'imply' keyword restricts a symbol to y or n, excluding m
when it is implied by y. This is the original behavior since
commit 237e3ad0f1 ("Kconfig: Introduce the "imply" keyword").

However, the author of this feature, Nicolas Pitre, stated that
the 'imply' keyword should not impose any restrictions.
(https://lkml.org/lkml/2020/2/19/714)

I agree, and want to get rid of this tricky behavior.

Suggested-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Nicolas Pitre <nico@fluxnic.net>
2020-03-13 10:05:34 +09:00
Bjorn Helgaas 2b5072b9df kconfig: fix documentation typos
Fix a couple typos in kconfig-language documentation.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-01-22 00:54:35 +09:00
Masahiro Yamada 8f268881d7 kconfig: remove ---help--- from documentation
Since commit 84af7a6194 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), scripts/checkpatch.pl warns the use of ---help---.

Kconfig still supports ---help---, but new code should avoid using it.
Let's stop advertising it in documentation.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2019-12-18 23:17:29 +09:00
Mauro Carvalho Chehab 168869492e docs: kbuild: fix build with pdf and fix some minor issues
The tag ".. include" should be replaced by ".. literalinclude" at
issues.rst, otherwise it causes TeX to crash due to excessive usage
of stack with Sphinx 2.0.

While here, solve a few minor issues at the kbuild book output by
adding extra blank lines.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
2019-07-15 11:03:04 -03:00
Mauro Carvalho Chehab cd238effef docs: kbuild: convert docs to ReST and rename to *.rst
The kbuild documentation clearly shows that the documents
there are written at different times: some use markdown,
some use their own peculiar logic to split sections.

Convert everything to ReST without affecting too much
the author's style and avoiding adding uneeded markups.

The conversion is actually:
  - add blank lines and identation in order to identify paragraphs;
  - fix tables markups;
  - add some lists markups;
  - mark literal blocks;
  - adjust title markups.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-06-14 14:21:21 -06:00