Messages in this thread | | | From | Arnd Bergmann <> | Date | Thu, 9 Dec 2021 08:45:30 +0100 | Subject | Re: question about all*config and COMPILE_TEST |
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On Thu, Dec 9, 2021 at 6:07 AM Kees Cook <keescook@chromium.org> wrote: > > tl;dr: is there a way to force a config default to "off" under > all*config builds, but still leave it configurable? (i.e. not "depends > on !COMPILE_TEST") > > I'm trying to understand a Kconfig behavior with regard to > COMPILE_TEST. I'm able to use an "all*config" target, followed by specific > additional config changes (e.g. turning off KCOV), but I can't enable > things like DEBUG_INFO because of their "depends on !COMPILE_TEST". > Whenever I want to examine debug info from all*config build I need to > patch lib/Kconfig.debug to remove the depends. I was hoping I could, > instead do:
This would be a minor hassle for my randconfig testing because I really want to have DEBUG_INFO disabled when building randconfigs in order to keep down compile times. I could however just force DEBUG_INFO=n the same way as forcing COMPILE_TEST=y at the moment.
> I then thought I could use: > > default !COMPILE_TEST > > since this works: > > config WERROR > bool "Compile the kernel with warnings as errors" > default COMPILE_TEST > > but I think the above is a no-op: it's the same as not having > "default COMPILE_TEST" when doing an all*config build: it'll be enabled > not because of COMPILE_TEST but because of the all*config pass.
Correct. One trick that works here is to use a 'choice' statement, as those still honor the 'default' value even for allmodconfig -- Kconfig has no idea which one of them is the 'all' version.
> How can I make DEBUG_INFO configurable, but default off under > all*config?
I'd try generalizing the "DWARF version" choice to offer 'none' as a default, like
choice prompt "Debug information" default DEBUG_INFO_NONE if COMPILE_TEST default DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT if DEBUG_KERNEL
config DEBUG_INFO_NONE bool "Turn off all debug information"
config DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT bool "Rely on the toolchain's implicit default DWARF version"
config DEBUG_INFO_DWARF4 bool "Generate DWARF Version 4 debuginfo"
config DEBUG_INFO_DWARF5 bool "Generate DWARF Version 5 debuginfo" depends on !CC_IS_CLANG || (CC_IS_CLANG && (AS_IS_LLVM || (AS_IS_GNU && AS_VERSION >= 23502))) depends on !DEBUG_INFO_BTF
endchoice
Arnd
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