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Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Arnaldo Carvalho de Melo , Josh Poimboeuf , Paolo Bonzini , Arnd Bergmann , Frederic Weisbecker , "Paul E. McKenney" , Jason Baron , Steven Rostedt , Ard Biesheuvel , Sami Tolvanen , "David S. Miller" , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki , Mathieu Desnoyers , Mel Gorman , Andrew Morton , Masahiro Yamada , Han Shen , Rik van Riel , Jann Horn , Dan Carpenter , Oleg Nesterov , Juri Lelli , Clark Williams , Yair Podemsky , Marcelo Tosatti , Daniel Wagner , Petr Tesarik , Shrikanth Hegde Subject: [PATCH v7 19/31] sched/clock, x86: Mark __sched_clock_stable key as allowed in .noinstr Date: Fri, 14 Nov 2025 16:10:46 +0100 Message-ID: <20251114151048.1061644-1-vschneid@redhat.com> In-Reply-To: <20251114150133.1056710-1-vschneid@redhat.com> References: <20251114150133.1056710-1-vschneid@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: AD447140003 X-Stat-Signature: 9dqnsnyhhxekr4bjfz35kub4ic8c5soa X-Rspam-User: X-HE-Tag: 1763133085-796462 X-HE-Meta: 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 ZBuZcOGo 64mw8c+Ga2o86r1Ed+sh4jsbc0ngCLgpOYWIuObssWCIZA3tUkLwZNOXsTecl8X2GKIovNj2MzBEHx3WzuRp2JmjZuVXkxAWcqx3lQaoDnhjLIBcSc9z01SQSQNDknY/xcuWSIAsLaUq+U7k+hlT5Yl4lIwGM8KaNJDOZChaDphYVjWOxL+HDYliGFPZQHqPP6JLImfi3ESoNxQ04RmipGXuzYhHd6c8kAK005JiK5meDq7wtxUEf3rTv2IH9yh76xOHIkFZPD0fJAWy40EdFKApDpwCpX79ZW4YFe2mEGKv6qknZV/52bJJbpI3T0HRXS8IPIxXCInfhXzem5kmYHLlRb7pmbEwzl1nRA32Y2q9F202X/F5aeb7o1vHkwi1sFjYS0wVyHC32CJ5C/q7H1ZOG9OtcBxAdPR6nqqkAdyHeTaJNJSYcYw0kBw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Later commits will cause objtool to warn about static keys being used in .noinstr sections in order to safely defer instruction patching IPIs targeted at NOHZ_FULL CPUs. __sched_clock_stable is used in .noinstr code, and can be modified at runtime (e.g. time_cpufreq_notifier()). Suppressing the text_poke_sync() IPI has little benefits for this key, as NOHZ_FULL is incompatible with an unstable TSC anyway. Mark it to let objtool know not to warn about it. Signed-off-by: Valentin Schneider --- kernel/sched/clock.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c index c1a028e99d2cd..5ee27349a4811 100644 --- a/kernel/sched/clock.c +++ b/kernel/sched/clock.c @@ -78,8 +78,11 @@ static DEFINE_STATIC_KEY_FALSE_RO(sched_clock_running); * * Similarly we start with __sched_clock_stable_early, thereby assuming we * will become stable, such that there's only a single 1 -> 0 transition. + * + * NOINSTR: an unstable TLC is incompatible with NOHZ_FULL, thus the text + * patching IPI would be the least of our concerns. */ -static DEFINE_STATIC_KEY_FALSE(__sched_clock_stable); +static DEFINE_STATIC_KEY_FALSE_NOINSTR(__sched_clock_stable); static int __sched_clock_stable_early = 1; /* -- 2.51.0