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[23.128.96.18]) by mx.google.com with ESMTP id s8si286158edc.481.2020.11.04.19.50.30; Wed, 04 Nov 2020 19:50:53 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=BDz3cQJp; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732668AbgKEAQA (ORCPT + 99 others); Wed, 4 Nov 2020 19:16:00 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:30632 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730651AbgKEAOS (ORCPT ); Wed, 4 Nov 2020 19:14:18 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1604535257; 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=WgNzPrMRWMTkptqOa05ejOci8goRgD8ij+h1kCV7zHo=; b=BDz3cQJp/QjxejeRqMCgAufhnLiJ5NS5L7DWinZSf/b2/VpvWHugPTJpcnIJEkanPE9Ger Py2FjNYy4pOgIYfLv2NVf3xdpCd8T9YC//J13XAjlS5TOVdt/3k6KqUWp1Pd2BklI/ui65 JJXXMqYdMCGNwe9lC/H4GXu9jaRvIns= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-244-ex9LEUj8M7ub4_d0L-DgDQ-1; Wed, 04 Nov 2020 19:14:13 -0500 X-MC-Unique: ex9LEUj8M7ub4_d0L-DgDQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2481C10082E8; Thu, 5 Nov 2020 00:14:11 +0000 (UTC) Received: from mail (ovpn-116-241.rdu2.redhat.com [10.10.116.241]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B3E1D1007600; Thu, 5 Nov 2020 00:14:06 +0000 (UTC) From: Andrea Arcangeli To: Thomas Gleixner Cc: YiFei Zhu , Linux Containers , YiFei Zhu , bpf , kernel list , Aleksa Sarai , Andy Lutomirski , David Laight , Dimitrios Skarlatos , Giuseppe Scrivano , Hubertus Franke , Jack Chen , Jann Horn , Josep Torrellas , Tianyin Xu , Tobin Feldman-Fitzthum , Tycho Andersen , Valentin Rothberg , Will Drewry , Jiri Kosina , Waiman Long , Josh Poimboeuf , Andi Kleen Subject: [PATCH 1/1] x86: deduplicate the spectre_v2_user documentation Date: Wed, 4 Nov 2020 19:14:06 -0500 Message-Id: <20201105001406.13005-2-aarcange@redhat.com> In-Reply-To: <20201105001406.13005-1-aarcange@redhat.com> References: <20201104234047.GA18850@redhat.com> <20201105001406.13005-1-aarcange@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This would need updating to make prctl be the new default, but it's simpler to delete it and refer to the dup. Signed-off-by: Andrea Arcangeli --- Documentation/admin-guide/hw-vuln/spectre.rst | 51 +------------------ 1 file changed, 2 insertions(+), 49 deletions(-) diff --git a/Documentation/admin-guide/hw-vuln/spectre.rst b/Documentation/admin-guide/hw-vuln/spectre.rst index 19b897cb1d45..ab7d402c1677 100644 --- a/Documentation/admin-guide/hw-vuln/spectre.rst +++ b/Documentation/admin-guide/hw-vuln/spectre.rst @@ -593,61 +593,14 @@ kernel command line. Not specifying this option is equivalent to spectre_v2=auto. -For user space mitigation: - - spectre_v2_user= - - [X86] Control mitigation of Spectre variant 2 - (indirect branch speculation) vulnerability between - user space tasks - - on - Unconditionally enable mitigations. Is - enforced by spectre_v2=on - - off - Unconditionally disable mitigations. Is - enforced by spectre_v2=off - - prctl - Indirect branch speculation is enabled, - but mitigation can be enabled via prctl - per thread. The mitigation control state - is inherited on fork. - - prctl,ibpb - Like "prctl" above, but only STIBP is - controlled per thread. IBPB is issued - always when switching between different user - space processes. - - seccomp - Same as "prctl" above, but all seccomp - threads will enable the mitigation unless - they explicitly opt out. - - seccomp,ibpb - Like "seccomp" above, but only STIBP is - controlled per thread. IBPB is issued - always when switching between different - user space processes. - - auto - Kernel selects the mitigation depending on - the available CPU features and vulnerability. - - Default mitigation: - If CONFIG_SECCOMP=y then "seccomp", otherwise "prctl" - - Not specifying this option is equivalent to - spectre_v2_user=auto. - In general the kernel by default selects reasonable mitigations for the current CPU. To disable Spectre variant 2 mitigations, boot with spectre_v2=off. Spectre variant 1 mitigations cannot be disabled. +For spectre_v2_user see :doc:`/admin-guide/kernel-parameters`. + Mitigation selection guide --------------------------