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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 Subject: [PATCH v6 18/29] sched/clock, x86: Mark __sched_clock_stable key as allowed in .noinstr Date: Fri, 10 Oct 2025 17:38:28 +0200 Message-ID: <20251010153839.151763-19-vschneid@redhat.com> In-Reply-To: <20251010153839.151763-1-vschneid@redhat.com> References: <20251010153839.151763-1-vschneid@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-Stat-Signature: 1k39jzsb5hzfghbg8tu8844acd366kza X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 75EA3A0023 X-HE-Tag: 1760111134-84873 X-HE-Meta: U2FsdGVkX18FaMhnIHrWDbj2eB913+84yb+u5LpYJ88cRI21RKuWJl0n0QDAV9bQePYrNcx5U1gGl+XWfDU8WI6SBs5TuAJ7soV0cSr9V68I0YXmxsr6zCs8SAHaq5w+MDyxTRS5tTxBvyFtOjiNRm3mEdMrZpW57m0siqbYYnnCPEcLb5KWsVFESKmjYGhiB/YJzNBOGXGEXwsS8I9fFawJdRluKQVhHWSASef4VALYEt9Zhb0JxkS69CYWm7QQYYQmrELKTWGmzcGDkDLTcdwXepogTauwaug/CUe2RZMZRk1cw3Pn3/H8O1NLuq3vDTtI7avp2IkzeO/TbOFjro1QapI+BYpPoQx+DwRZMjrsIuEtSpNtxrmqUknMXAYGfq8AaTcrNvrYDW5tfPF9+psCYYgZgM197MQ3ppkGlgD49hwx+egGk1HGHaxdDV59qSKH0lwKtyiUEXy4tuMIcHdFlezSqpaXGcNmAJXV17JnHCiXditQuU4QOXr0wTUEBDjmGvBaSyXD2QUts8IUlagoD/iHGimHYpmIWGcig1b8t+OiBXlCJoULdKM5Ru5Aw+O9V6qGIMEUZLelpD/DRS/cWGo7Khj2VOOqw5rXD4FX+SFj/wlRcQBWm6fO7Gs0MkpZPv+s7aUApcd5v16IQnxZCZ9ASyAVgvjEfPA1bBOcadc9IEdIUicaUpX74ZlHz2SLIqaVrEHfE9QxAfs6uEjDcauDSelKn/bYi/r824opLLqJPun3a0bLJ49VCS7sCPeWpilj2wEr6CvaFZCRvz7EjqIIeulVV7bGIEz3cBousX2xkbHdB99P+b97Fh9CTX1ZG5aCe+/fZrd2uQ2hQUcMl9PoPV5NJ8OJ4wyq8kqyCls6EoJutlSCiv7pSE5Boz7MzMR+BUZHE4fHhEpJDJQOdvnJ8RpM1MFIIsaMolCHnYjGMgoiv/OjRBhan7/ypcweW2kqsG/lWcRIZ0c UQdICyBX OaqD2Gk1j9QeRZH1AlJp2pcZzmgRcXO3KJWqMqERBcAxZpAanA17oPVQVdrm89SrWM/M1F22OgvpgzsBmDiOq89DT3cSjB0sDKVRFg/C+hsXAQUJPKeQttUIF0FG0nGjOU2NOWFjrJ6DHjeyW+Qma0G4qynKsMZKHr2TgpDZpblTSB7m5FtYsUzX0KMLCN+PcC33jCWsLC01owgs0ZCa+sfKN+IAo4BkdlF7ApQYXboTYHQIHVlciMk8+8Hmchjl97w4LvjmU3kCV3qBu2kB+oWzD+6izlgyL2vNrbD44yLClg3WNpkZRnTK/0++EcMAuSqzP9lwKkL+nnAvATvwDFRLZ/yNegk+QAPmLeVI5VkdPG9CduuH+6LRd5UIHBWLkxpcSfYcH21ltXo2Qt1EZg4/Zxq/A7p/oBy1gjxPUdJYnkzB2oHQ3wnSZg/sON5HzEYMCHgTf99e/YAIGfUc9IhawOSSztcRGFOBY 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..e6ef71d74ac95 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. + * + * Allowed in .noinstr as 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