Since commit fde192511b ("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>
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>
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:
- df8df5e4bc ("usb: get rid of 'choice' for legacy gadget drivers")
- bfb57ef054 ("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 fa64e5f6a3 ("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>
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>
This sentence does not make sense due to a typo. Fix it.
Fixes: def2fbffe6 ("kconfig: allow symbols implied by y to become m")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
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>
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>
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>
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>
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>
`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>
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>
"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>
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>
- 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
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>
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>
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>
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>
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>
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>
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>
