From mboxrd@z Thu Jan 1 00:00:00 1970 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 6A659256C76 for ; Fri, 10 Oct 2025 15:45:21 +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=1760111124; cv=none; b=Ejdk8Zv9aJGGl51aEZNdkgCTMvWC2BOLE6qw4dpuocftP4osk27ZxnFsyxGZkDUixBE4IOG8HkRxxqDZyZ1XYvphgPc+3dnEqFhHcwEJV04OJxwGL7fKnDtIrf00X+V7zNOAEaUh7yZPRqKvGmAkd9YOatuXBdzbCg8ZR9FjB78= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760111124; c=relaxed/simple; bh=WXVvOMZrtZn1MmtxQTOtF5uE/eYw4tg9hMgNZBzw6ZA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=B2/DRpgrW95bmRgS28kmp669uze9EJjg+VEMidCbgAymcg3d+ZRCpLJkyyS1ZzzeVRZrM8nnqtHmdG+FILYbEQEFx9cl67EajKu50mhdtYyQ5UKsc1SyU+BTWNd11X/hrOSs49FqMfQ5sg0BaIRqFSWEhRMP0D9EoIHza2btRy8= 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=fMWvgUm3; 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="fMWvgUm3" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1760111121; 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=Au5DdAV6tUN4ivYmpx7gvL4Yw9R7cu+pTuIQIzQAh6Y=; b=fMWvgUm3Mw/URoU6xs5BCu9jRJ887xwGdpszJD6f8Nm1s0AQEPAPAiEuao2f4wfVzmkG38 eHEL1kpyNWZamPbfvN0+mQ/cvLqLHbmGSZuIjYrCxHhyF8evLmzA1WYcwkIfeA5QBaN+X9 x+9xEtuxTPdishn0tZKi1+qLOK4oGyU= Received: from mx-prod-mc-02.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-301-55_B1TgXOS293WUuB8x3mw-1; Fri, 10 Oct 2025 11:45:16 -0400 X-MC-Unique: 55_B1TgXOS293WUuB8x3mw-1 X-Mimecast-MFC-AGG-ID: 55_B1TgXOS293WUuB8x3mw_1760111110 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 88B5819560BF; Fri, 10 Oct 2025 15:45:10 +0000 (UTC) Received: from vschneid-thinkpadt14sgen2i.remote.csb (unknown [10.45.224.29]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C86011800576; Fri, 10 Oct 2025 15:44:55 +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 Subject: [PATCH v6 17/29] x86/speculation/mds: Mark cpu_buf_idle_clear key as allowed in .noinstr Date: Fri, 10 Oct 2025 17:38:27 +0200 Message-ID: <20251010153839.151763-18-vschneid@redhat.com> In-Reply-To: <20251010153839.151763-1-vschneid@redhat.com> References: <20251010153839.151763-1-vschneid@redhat.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 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. cpu_buf_idle_clear is used in .noinstr code, and can be modified at runtime (SMT hotplug). Suppressing the text_poke_sync() IPI has little benefits for this key, as hotplug implies eventually going through takedown_cpu() -> stop_machine_cpuslocked() which is going to cause interference on all online CPUs anyway. Mark it to let objtool know not to warn about it. Signed-off-by: Valentin Schneider --- arch/x86/kernel/cpu/bugs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c index 36dcfc5105be9..3aca329a853b5 100644 --- a/arch/x86/kernel/cpu/bugs.c +++ b/arch/x86/kernel/cpu/bugs.c @@ -182,7 +182,7 @@ DEFINE_STATIC_KEY_FALSE(switch_vcpu_ibpb); EXPORT_SYMBOL_GPL(switch_vcpu_ibpb); /* Control CPU buffer clear before idling (halt, mwait) */ -DEFINE_STATIC_KEY_FALSE(cpu_buf_idle_clear); +DEFINE_STATIC_KEY_FALSE_NOINSTR(cpu_buf_idle_clear); EXPORT_SYMBOL_GPL(cpu_buf_idle_clear); /* -- 2.51.0