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2024-11-04kconfig: remove support for "bool" prompt for choice entriesMasahiro Yamada
Since commit fde192511bdb ("kconfig: remove tristate choice support"), all choice blocks are now boolean. There is no longer a need to specify the choice type explicitly. All "bool" prompts in choice entries have been converted to "prompt". This commit removes support for the "bool" syntax in choice entries. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-09-07Documentation: kconfig: explicitly document missing promptStephen Brennan
There are a few lines in the kbuild-language.rst document which obliquely reference the behavior of config options without prompts. But there is nothing in the obvious location that explicitly calls out that users cannot edit config options unless they have a prompt. Signed-off-by: Stephen Brennan <stephen.s.brennan@oracle.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-07-16kconfig: remove tristate choice supportMasahiro Yamada
I previously submitted a fix for a bug in the choice feature [1], where I mentioned, "Another (much cleaner) approach would be to remove the tristate choice support entirely". There are more issues in the tristate choice feature. For example, you can observe a couple of bugs in the following test code. [Test Code] config MODULES def_bool y modules choice prompt "tristate choice" default A config A tristate "A" config B tristate "B" endchoice Bug 1: the 'default' property is not correctly processed 'make alldefconfig' produces: CONFIG_MODULES=y # CONFIG_A is not set # CONFIG_B is not set However, the correct output should be: CONFIG_MODULES=y CONFIG_A=y # CONFIG_B is not set The unit test file, scripts/kconfig/tests/choice/alldef_expected_config, is wrong as well. Bug 2: choice members never get 'y' with randconfig For the test code above, the following combinations are possible: A B (1) y n (2) n y (3) m m (4) m n (5) n m (6) n n 'make randconfig' never produces (1) or (2). These bugs are fixable, but a more critical problem is the lack of a sensible syntax to specify the default for the tristate choice. The default for the choice must be one of the choice members, which cannot specify any of the patterns (3) through (6) above. In addition, I have never seen it being used in a useful way. The following commits removed unnecessary use of tristate choices: - df8df5e4bc37 ("usb: get rid of 'choice' for legacy gadget drivers") - bfb57ef0544a ("rapidio: remove choice for enumeration") This commit removes the tristate choice support entirely, which allows me to delete a lot of code, making further refactoring easier. Note: This includes the revert of commit fa64e5f6a35e ("kconfig/symbol.c: handle choice_values that depend on 'm' symbols"). It was suspicious because it did not address the root cause but introduced inconsistency in visibility between choice members and other symbols. [1]: https://lore.kernel.org/linux-kbuild/20240427104231.2728905-1-masahiroy@kernel.org/T/#m0a1bb6992581462ceca861b409bb33cb8fd7dbae Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2024-06-06kconfig: doc: document behavior of 'select' and 'imply' followed by 'if'Masahiro Yamada
Documentation/kbuild/kconfig-language.rst explains the behavior of 'select' as follows: reverse dependencies can be used to force a lower limit of another symbol. The value of the current menu symbol is used as the minimal value <symbol> can be set to. This is not true when the 'select' property is followed by 'if'. [Test Code] config MODULES def_bool y modules config A def_tristate y select C if B config B def_tristate m config C tristate [Result] CONFIG_MODULES=y CONFIG_A=y CONFIG_B=m CONFIG_C=m If "the value of A is used as the minimal value C can be set to", C must be 'y'. The actual behavior is "C is selected by (A && B)". The lower limit of C is downgraded due to B being 'm'. This behavior is kind of weird, and this has arisen several times in the mailing list. I do not know whether it is a bug or intended behavior. Anyway, it is not feasible to change it now because many Kconfig files are written based on this behavior. The same applies to 'imply'. Document this (but reserve the possibility for a future change). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
2024-06-06kconfig: doc: fix a typo in the note about 'imply'Masahiro Yamada
This sentence does not make sense due to a typo. Fix it. Fixes: def2fbffe62c ("kconfig: allow symbols implied by y to become m") Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
2024-05-02kconfig: remove 'optional' property supportMasahiro Yamada
The 'choice' statement is primarily used to exclusively select one option, but the 'optional' property allows all entries to be disabled. In the following example, both A and B can be disabled simultaneously: choice prompt "choose A, B, or nothing" optional config A bool "A" config B bool "B" endchoice You can achieve the equivalent outcome by other means. A common solution is to add another option to guard the choice block. In the following example, you can set ENABLE_A_B_CHOICE=n to disable the entire choice block: choice prompt "choose A or B" depends on ENABLE_A_B_CHOICE config A bool "A" config B bool "B" endchoice Another approach is to insert one more entry: choice prompt "choose A, B, or disable both" config A bool "A" config B bool "B" config DISABLE_A_AND_B bool "choose this to disable both A and B" endchoice Some real examples are DEBUG_INFO_NONE, INITRAMFS_COMPRESSION_NONE, LTO_NONE, etc. The 'optional' property is even more unnecessary for a tristate choice. Without the 'optional' property, you can disable A and B; you can set 'm' in the choice prompt, and disable A and B individually: choice prompt "choose one built-in or make them modular" config A tristate "A" config B tristate "B" endchoice In conclusion, the 'optional' property was unneeded. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <n.schier@avm.de>
2024-03-10kconfig: remove named choice supportMasahiro Yamada
Commit 5a1aa8a1aff6 ("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>
2023-09-25Documentation: kbuild: explain handling optional dependenciesArnd Bergmann
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>
2022-08-21asm goto: eradicate CC_HAS_ASM_GOTONick Desaulniers
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>
2022-07-27docs: kbuild: fix typoBaruch Siach
on -> one. Signed-off-by: Baruch Siach <baruch@tkos.co.il> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-04-06docs: kbuild: add references on Kconfig semanticsNecip Fazil Yildiran
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>
2022-01-08doc: kbuild: fix default in `imply` tableMiguel Ojeda
`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>
2021-04-14kconfig: change "modules" from sub-option to first-level attributeMasahiro Yamada
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>
2021-04-14kconfig: remove allnoconfig_y optionMasahiro Yamada
Now that the only user, CONFIG_EMBEDDED has stopped using this option, remove it entirely. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-04-14kconfig: change defconfig_list option to environment variableMasahiro Yamada
"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>
2020-12-21Documentation/kbuild: Document platform dependency practisesGeert Uytterhoeven
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>
2020-12-21Documentation/kbuild: Document COMPILE_TEST dependenciesGeert Uytterhoeven
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>
2020-08-09Merge tag 'kbuild-v5.9' of ↵Linus Torvalds
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
2020-08-10kbuild: Replace HTTP links with HTTPS onesAlexander A. Klimov
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>
2020-07-13Documentation: kbuild/kconfig-language: eliminate duplicated wordRandy Dunlap
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>
2020-07-07kbuild: remove cc-option test of -fno-stack-protectorMasahiro Yamada
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>
2020-03-13kconfig: make 'imply' obey the direct dependencyMasahiro Yamada
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>
2020-03-13kconfig: allow symbols implied by y to become mMasahiro Yamada
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 237e3ad0f195 ("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>
2020-01-22kconfig: fix documentation typosBjorn Helgaas
Fix a couple typos in kconfig-language documentation. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2019-12-18kconfig: remove ---help--- from documentationMasahiro Yamada
Since commit 84af7a6194e4 ("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>
2019-07-15docs: kbuild: fix build with pdf and fix some minor issuesMauro Carvalho Chehab
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>
2019-06-14docs: kbuild: convert docs to ReST and rename to *.rstMauro Carvalho Chehab
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>