From nobody Wed Dec 17 06:08:53 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 09377176ADE for ; Fri, 14 Nov 2025 15:11:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763133085; cv=none; b=b2ZzBikzfiQI3bA7dYcg8eOOMhAgMUw8wKcsjavN4mLP2jcgShIOFkGtosWN//YKtM3G//IeRac5HIjwsw7er4Cl6gSb/5vr2WpPsYEK9PYhHd5ypakxMfhIru5A8WSAwq91+PR2sDQSa/dRv1IiM5yFTImPE7gIGL5fTXo0Mp8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763133085; c=relaxed/simple; bh=DjmflE6ccSmR8hXooCtO/38G4Xihytqv9kmTm6nuKB0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=aLfLM6qtUVE3IBw2TkJNjRsq+WPkwGdQZ5+lhUAS0Kpke6pg3sd9EXvXs471oGdK47kTgM0Dc11LKSuEIF0hEf+hRdX4SkzLjWUqlRS5ARnvRrDFk7haiNn0Kvy8ywBtYY2YAmxF1TdbrZGmYdBQJFZhFjOKtRN6sIopSJb4bl8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=VIHU9Zde; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="VIHU9Zde" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1763133083; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=6Z88cIt4bkuwH7lP1X8YYrnTJPptFDIGXgV9h1p1EOM=; b=VIHU9ZdeHO9V+vVe1KRi4oRxi87q/2wOIEiI4rh74FSuEpg9zVmiaPzlO3ypaF63NoWD4+ MnjJDwLoC6ffZnVhUc56os2Ms00qshUTy5EA0N6GloftUc93dKDlwc+kP8BSjGpQ0KdhWX BLGEx0ZkIEloLhHr2xvMDtd8J5SGczo= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-141-rdbQPBGSMPqDX7mD8R_GZA-1; Fri, 14 Nov 2025 10:11:20 -0500 X-MC-Unique: rdbQPBGSMPqDX7mD8R_GZA-1 X-Mimecast-MFC-AGG-ID: rdbQPBGSMPqDX7mD8R_GZA_1763133073 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 15A5718AB40A; Fri, 14 Nov 2025 15:11:13 +0000 (UTC) Received: from vschneid-thinkpadt14sgen2i.remote.csb (unknown [10.45.226.10]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id F2CBF300018D; Fri, 14 Nov 2025 15:10:57 +0000 (UTC) From: Valentin Schneider To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, rcu@vger.kernel.org, x86@kernel.org, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, linux-arch@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Content-Type: text/plain; charset="utf-8" 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 =3D 1; =20 /* --=20 2.51.0