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 CAC6CCCA476 for ; Fri, 10 Oct 2025 15:45:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Au5DdAV6tUN4ivYmpx7gvL4Yw9R7cu+pTuIQIzQAh6Y=; b=sI56fYMbjX0LAsbcazusV2z9Ya U7fTBzRP16vmIRCO7htEDIc/LPXT+FZ8q0ozBlo0mvGjLQSxjHUt23WGwfIVLJmTBilStTpsigJ2+ wmHLAanTnzyFw1nx94i4rUbQ/m32JY36qpeldY68OlfVaASOe+WlHcduPpMNnppDGSDk8i1HRG+0A kj58LrgaUqYSxEUP2dvdeVOyzgPGA0Xqo8tyT2KUTisoivv8El62K0R1JLq61vFxNL5wc0fslifPh 909f3+qIS27d6R2V/Kidhuh10IwgTBvxZ5Z32NkPbJBV7gCWudVqCiWFjR2UjnEUhP9tMWvDA2W7u RijHidMg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v7FJ8-00000008slh-3QeY; Fri, 10 Oct 2025 15:45:26 +0000 Received: from desiato.infradead.org ([2001:8b0:10b:1:d65d:64ff:fe57:4e05]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1v7FJ7-00000008sjx-0ia7 for linux-arm-kernel@bombadil.infradead.org; Fri, 10 Oct 2025 15:45:25 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Content-Transfer-Encoding:MIME-Version :References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=Au5DdAV6tUN4ivYmpx7gvL4Yw9R7cu+pTuIQIzQAh6Y=; b=D8kbPlIO7R6w5osSQXAnY1q58e 8mvymVbH0wXZFK2xI1cEixuwgi5ztswRmlwa4QDJTeznjDqyvtSK5/IR9SBDxdOQDM7BSsGnhn0DA LUnl4yARmD+u+q9B6jI/pdwtpbWyBxj2Q/5ZxkEe2oCmfjLMxkNncBFydigUygcA6koxd2xveUS10 Tw9hvF/sfPFW8Uvt3pWpYrDGzYEAQv2RA7N8XNwYhb3JLznreXe+OrQBlMHUMeS7KO5pB9sPohOTB K3kV+QjMke4p6BNbjM4HH0GlsIbifYWqK8ABr1CY6HzKSr9s5eishBkf8e1qdpmyfNwyF8GMrncuW 2ox76Y/g==; Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by desiato.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1v7FJ3-00000002FAQ-3WTH for linux-arm-kernel@lists.infradead.org; Fri, 10 Oct 2025 15:45:23 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1760111120; 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=db1BVpx3kGngRsVbV5UeRSowo81+ieOVT6k8dKHW3Lm815sv/lxQ+hlcBhPb3TMVMO61d8 N73tz5f5KuaHLrhOYvBXo9KHAdKp5z9DNV0B5B8zjzA4u6h/x4SO+FC56T/JA7izkO0Ngj Ui0ReMAijTfVCcwFKCs4yKolEaeGWWU= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1760111120; 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=db1BVpx3kGngRsVbV5UeRSowo81+ieOVT6k8dKHW3Lm815sv/lxQ+hlcBhPb3TMVMO61d8 N73tz5f5KuaHLrhOYvBXo9KHAdKp5z9DNV0B5B8zjzA4u6h/x4SO+FC56T/JA7izkO0Ngj Ui0ReMAijTfVCcwFKCs4yKolEaeGWWU= 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> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251010_164522_279509_68FD02D2 X-CRM114-Status: GOOD ( 14.63 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=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. 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