From: Peter Oberparleiter <oberpar@linux.ibm.com>
To: Sasha Levin <sashal@kernel.org>, linux-kernel@vger.kernel.org
Cc: Alexander Potapenko <glider@google.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Anton Ivanov <anton.ivanov@cambridgegreys.com>,
Bill Wendling <morbo@google.com>, Borislav Petkov <bp@alien8.de>,
Chuck Wolber <chuck@wolber.net>,
Dave Hansen <dave.hansen@linux.intel.com>,
Dmitry Vyukov <dvyukov@google.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Johannes Berg <johannes@sipsolutions.net>,
Justin Stitt <justinstitt@google.com>,
kasan-dev@googlegroups.com, linux-kbuild@vger.kernel.org,
linux-um@lists.infradead.org, llvm@lists.linux.dev,
Marco Elver <elver@google.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Nicolas Schier <nsc@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Richard Weinberger <richard@nod.at>,
Thomas Gleixner <tglx@kernel.org>,
x86@kernel.org
Subject: Re: [PATCH v2 19/20] gcov: add MC/DC condition coverage support
Date: Thu, 5 Nov 2026 18:56:10 +0100 [thread overview]
Message-ID: <dd2b2658-cb4a-4ba9-b69c-470d433a0ef5@linux.ibm.com> (raw)
In-Reply-To: <20261103015238.3780910-20-sashal@kernel.org>
On 03.11.2026 02:52, Sasha Levin wrote:
> Support CONFIG_COVERAGE_MCDC with gcov, using GCC's MC/DC condition
> coverage instrumentation (-fcondition-coverage), which is available
> since GCC 14. The data is shown by "gcov --conditions".
>
> Add -fcondition-coverage to the gcov compiler flags when enabled, and
> disable the warnings about decisions it leaves out, as is done for
> Clang. Both are gated on the config option to avoid Clang warnings
> about unknown options.
>
> Also add -fcondition-coverage to CFLAGS_REMOVE in the x86 UML vDSO
> Makefile to prevent instrumentation of userspace vDSO code.
>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
Looks good, minor comment below.
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
[...]
> @@ -108,8 +108,8 @@ config COVERAGE_PROFILE_ALL
>
> config COVERAGE_MCDC
> bool "Measure modified condition/decision coverage (MC/DC)"
> - depends on LLVM_COV_KERNEL
> - depends on CLANG_VERSION >= 220000 || !WERROR
> + depends on LLVM_COV_KERNEL || (GCOV_KERNEL && CC_HAS_CONDITION_COVERAGE)
> + depends on !LLVM_COV_KERNEL || CLANG_VERSION >= 220000 || !WERROR
Would it make sense to transform this for readability, i.e.
depends on !(LLVM_COV_KERNEL && CLANG_VERSION < 220000 && WERROR)
--
Peter Oberparleiter
Linux on IBM Z Development - IBM Germany R&D
next prev parent reply other threads:[~2026-11-05 17:57 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-03 1:52 [PATCH v2 00/20] Unify code coverage and add Clang source-based coverage with MC/DC Sasha Levin
2026-11-03 1:52 ` [PATCH v2 01/20] coverage: move gcov and kcov under kernel/coverage/ Sasha Levin
2026-11-05 17:38 ` Peter Oberparleiter
2026-11-03 1:52 ` [PATCH v2 02/20] kbuild: unify static coverage instrumentation as COVERAGE_PROFILE Sasha Levin
2026-11-03 1:52 ` [PATCH v2 03/20] coverage: add a common debugfs interface Sasha Levin
2026-11-05 17:49 ` Peter Oberparleiter
2026-11-06 1:05 ` Sasha Levin
2026-11-03 1:52 ` [PATCH v2 04/20] compiler_types.h: Don't instrument __always_inline functions for coverage Sasha Levin
2026-11-03 1:52 ` [PATCH v2 05/20] context_tracking: Always inline the empty stubs called from noinstr code Sasha Levin
2026-11-03 1:52 ` [PATCH v2 06/20] lockdep: " Sasha Levin
2026-11-03 1:52 ` [PATCH v2 07/20] perf: Always inline the empty perf_lopwr_cb() stub Sasha Levin
2026-11-03 1:52 ` [PATCH v2 08/20] rseq: Always inline the empty stubs called from noinstr code Sasha Levin
2026-11-03 1:52 ` [PATCH v2 09/20] x86: Always inline " Sasha Levin
2026-11-03 1:52 ` [PATCH v2 10/20] x86/sev: Use non-instrumented bitops in the GHCB accessors Sasha Levin
2026-11-04 13:36 ` Sean Christopherson
2026-11-03 1:52 ` [PATCH v2 11/20] objtool: Detect code coverage instrumentation in noinstr code Sasha Levin
2026-11-03 1:52 ` [PATCH v2 12/20] x86/sev: Stop excluding noinstr.o from code coverage Sasha Levin
2026-11-03 1:52 ` [PATCH v2 13/20] x86/entry: Stop excluding the entry code from KCOV Sasha Levin
2026-11-03 1:52 ` [PATCH v2 14/20] coverage: add Clang's source-based code coverage Sasha Levin
2026-11-03 1:52 ` [PATCH v2 15/20] x86: Enable " Sasha Levin
2026-11-03 1:52 ` [PATCH v2 16/20] coverage: add MC/DC measurement Sasha Levin
2026-11-03 1:52 ` [PATCH v2 17/20] gcov: fix gcov_info_add() merge semantics for IOR counters Sasha Levin
2026-11-05 17:50 ` Peter Oberparleiter
2026-11-03 1:52 ` [PATCH v2 18/20] kconfig: add CC_HAS_CONDITION_COVERAGE for MC/DC support detection Sasha Levin
2026-11-03 1:52 ` [PATCH v2 19/20] gcov: add MC/DC condition coverage support Sasha Levin
2026-11-05 17:56 ` Peter Oberparleiter [this message]
2026-11-06 1:05 ` Sasha Levin
2026-11-03 1:52 ` [PATCH v2 20/20] Documentation: dev-tools: document the common code coverage interface Sasha Levin
2026-11-05 17:36 ` [PATCH v2 00/20] Unify code coverage and add Clang source-based coverage with MC/DC Peter Oberparleiter
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=dd2b2658-cb4a-4ba9-b69c-470d433a0ef5@linux.ibm.com \
--to=oberpar@linux.ibm.com \
--cc=andreyknvl@gmail.com \
--cc=anton.ivanov@cambridgegreys.com \
--cc=bp@alien8.de \
--cc=chuck@wolber.net \
--cc=dave.hansen@linux.intel.com \
--cc=dvyukov@google.com \
--cc=elver@google.com \
--cc=glider@google.com \
--cc=hpa@zytor.com \
--cc=johannes@sipsolutions.net \
--cc=justinstitt@google.com \
--cc=kasan-dev@googlegroups.com \
--cc=linux-kbuild@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-um@lists.infradead.org \
--cc=llvm@lists.linux.dev \
--cc=mhiramat@kernel.org \
--cc=mingo@redhat.com \
--cc=morbo@google.com \
--cc=nathan@kernel.org \
--cc=ndesaulniers@google.com \
--cc=nsc@kernel.org \
--cc=peterz@infradead.org \
--cc=richard@nod.at \
--cc=sashal@kernel.org \
--cc=tglx@kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®