From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8BDC3CE7B1B for ; Fri, 14 Nov 2025 15:11:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=NW1SM+X9eo3B2MuM6toD+4P23MMLadIXuIpaIim7Gzg=; b=1msGaU+T0/Gxyj VfhnVkmbFbJGmdyduZ7B+Ty0qFtrz975TPGgW71RSr+Ul53cYjcChTb/btW+0IzFGwOWIgRlWvIOz MAR1r173rt+DZVVvStl/vW8LUuxEpoUdoeDv+FulPooA3dW5Wk/wS/yuLz60XUE9kNwfNiopKMRRQ GiXWbaTj/QLwRWlaJPjaOY60XZ+9m8umbTvXvIMpGjTMe7LSMH/PSAo3BcR40C7bY4+KK/4RyT4Tk E8kUm1gVt471u1dLRn0xs/PowIc9zmdPgR+G+9htkfWD/GPcJTZNvfiBEFq+vZ7cD7YOcZhStlmPZ m8a1AqKQpxxxWkkBNWLw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vJvSS-0000000CTHe-1qSy; Fri, 14 Nov 2025 15:11:28 +0000 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vJvSQ-0000000CTGj-0INK for linux-riscv@lists.infradead.org; Fri, 14 Nov 2025 15:11:27 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1763133085; 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=YY1kTrYG1/mOUJvSTs1O26BFGEypIUKhi/qzXxfth8oGz7BoJzBNPsCZ1r4PsdVD+DckQ+ WtqL3XuyY86dVPU2x436XLkMzkZ+og6VpkimaMS6zQRytDv5pWq1UtjHCcDR8zqZ+U4Wsj OtDj/cL2HlVu4JFKvICENMA/IlWCAp4= 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> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251114_071126_184508_7361BD04 X-CRM114-Status: GOOD ( 14.74 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org 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 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv