From: Kees Cook <keescook@chromium.org>
To: Masahiro Yamada <masahiroy@kernel.org>, Arnd Bergmann <arnd@arndb.de>
Cc: linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: question about all*config and COMPILE_TEST
Date: Wed, 8 Dec 2021 21:07:51 -0800 [thread overview]
Message-ID: <202112082057.C993DC6881@keescook> (raw)
Hi,
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:
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 0e2de4b375f3..e8533ffc92c3 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -212,7 +212,8 @@ menu "Compile-time checks and compiler options"
config DEBUG_INFO
bool "Compile the kernel with debug info"
- depends on DEBUG_KERNEL && !COMPILE_TEST
+ depends on DEBUG_KERNEL
+ default n if COMPILE_TEST
help
If you say Y here the resulting kernel image will include
debugging info resulting in a larger kernel image.
Which would turn this off when COMPILE_TEST was enabled, but I assume it
doesn't work because an all*config target turns everything on first, and
therefore this "default" gets ignored since DEBUG_INFO already has a
value set.
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.
How can I make DEBUG_INFO configurable, but default off under
all*config?
Thanks!
--
Kees Cook
next reply other threads:[~2021-12-09 5:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-09 5:07 Kees Cook [this message]
2021-12-09 7:45 ` question about all*config and COMPILE_TEST Arnd Bergmann
2021-12-10 0:07 ` Kees Cook
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