From patchwork Tue Apr 29 11:32:35 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Valentin Schneider X-Patchwork-Id: 885941 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 C46DC2C1E22 for ; Tue, 29 Apr 2025 11:42:59 +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=1745926981; cv=none; b=Bntbw/JPhPr3xPwjDPvkBLY/TNcyHwN+js3u+vn1qSuRkuRfkDxNmyxQw3FF2LzRn7DYz7evkVZQftJUURIOrP0kOUZGDMt3Io84V6dxiA6s84L8Fvvoqahy6c8HmOSzITjTOQ86Junp8ClaELFdv0t86/v+NL83nPZU6wqOrYY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745926981; c=relaxed/simple; bh=apD04pUdZyMk2ObFIQHJLHKGQEs48DRM9/gA4unUYAs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mWozlXrn5j+OypG6Q1pzQvDZmolzF1jN3DSsvmf9RUXAA6h0XhxPuaG64iyMFeOPo82H2NZbSNhwfC9v9cG7ac54T6Y4tqw/TToirBewRoPBKj/C7a5rJZS0+z33F7242s32gO3NPKSa1We5r6mDgOM22AykmQuSJ7s0i05E9B0= 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=OG60NINd; 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="OG60NINd" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1745926979; 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=boHlb9VW5lBF1DESnR599lKlLKrAVEqa90mhXCcqUlU=; b=OG60NINd57rMMYgVBFhfhCyLqtYzH9u51hu0EnEqnp/6zld80QaEaN6xeNpQwUnKonbUj6 r0adEVVzRVnNKrIxIIrizNsA/FTzLbYP2R4aubaP2fJvrPl6/1QQmlKifha26pMWuVFTx2 E+gbdXGzqOckTJu07S1kMALa7lDabjs= 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-25-sPKCJ77MPxe-Wi8VmOXKtA-1; Tue, 29 Apr 2025 07:42:56 -0400 X-MC-Unique: sPKCJ77MPxe-Wi8VmOXKtA-1 X-Mimecast-MFC-AGG-ID: sPKCJ77MPxe-Wi8VmOXKtA_1745926972 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (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 255621956077; Tue, 29 Apr 2025 11:42:52 +0000 (UTC) Received: from vschneid-thinkpadt14sgen2i.remote.csb (unknown [10.45.225.102]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4BE4E19560A3; Tue, 29 Apr 2025 11:42:23 +0000 (UTC) From: Valentin Schneider To: linux-kernel@vger.kernel.org, virtualization@lists.linux.dev, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linux-riscv@lists.infradead.org, linux-perf-users@vger.kernel.org, kvm@vger.kernel.org, linux-arch@vger.kernel.org, linux-modules@vger.kernel.org, linux-trace-kernel@vger.kernel.org, rcu@vger.kernel.org, linux-hardening@vger.kernel.org, linux-kselftest@vger.kernel.org, bpf@vger.kernel.org Cc: Juri Lelli , Marcelo Tosatti , Yair Podemsky , Josh Poimboeuf , Daniel Wagner , Petr Tesarik , Nicolas Saenz Julienne , Frederic Weisbecker , "Paul E. McKenney" , Dave Hansen , Sean Christopherson , Juergen Gross , Ajay Kaher , Alexey Makhalov , Broadcom internal kernel review list , Russell King , Catalin Marinas , Will Deacon , Huacai Chen , WANG Xuerui , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Peter Zijlstra , Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , "Liang, Kan" , Pawan Gupta , Paolo Bonzini , Arnd Bergmann , Jason Baron , Steven Rostedt , Ard Biesheuvel , Luis Chamberlain , Petr Pavlu , Sami Tolvanen , Daniel Gomez , Naveen N Rao , Anil S Keshavamurthy , "David S. Miller" , Masami Hiramatsu , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman , Kees Cook , Shuah Khan , Masahiro Yamada , Alice Ryhl , Miguel Ojeda , "Mike Rapoport (Microsoft)" , Rong Xu , Rafael Aquini , Song Liu , Andrii Nakryiko , Dan Carpenter , Brian Gerst , "Kirill A. Shutemov" , Benjamin Berg , Vishal Annapurve , Randy Dunlap , John Stultz , Tiezhu Yang Subject: [PATCH v5 18/25] sched/clock, x86: Mark __sched_clock_stable key as allowed in .noinstr Date: Tue, 29 Apr 2025 13:32:35 +0200 Message-ID: <20250429113242.998312-19-vschneid@redhat.com> In-Reply-To: <20250429113242.998312-1-vschneid@redhat.com> References: <20250429113242.998312-1-vschneid@redhat.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 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 200e5568b9894..e59986bc14a43 100644 --- a/kernel/sched/clock.c +++ b/kernel/sched/clock.c @@ -75,8 +75,11 @@ 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; /*