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 X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F2910C6379D for ; Tue, 17 Nov 2020 23:50:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9ADE920707 for ; Tue, 17 Nov 2020 23:50:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="lyz/gKGi" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728853AbgKQXuG (ORCPT ); Tue, 17 Nov 2020 18:50:06 -0500 Received: from smtp-fw-33001.amazon.com ([207.171.190.10]:64396 "EHLO smtp-fw-33001.amazon.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728650AbgKQXuF (ORCPT ); Tue, 17 Nov 2020 18:50:05 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1605657005; x=1637193005; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=yVijNXJfZpB9jcbWLbG3sANy1ieOt38EwuJJVRwYsWQ=; b=lyz/gKGizT3kIt3ADM1jG31G/sVjpMJW6iTeczTXu4xJOhQhgdak0o0T fWjAPDA5xa0JfoqunR08mlN2Ijsjtv78+ZPcA79gp2/6L28hwemy8TYNI oa/jD82kxXd27uxfinhQ56pyFFlWF7fnto+CW/R1EPx6JdvPzQJ9je0wq Y=; X-IronPort-AV: E=Sophos;i="5.77,486,1596499200"; d="scan'208";a="95124746" Received: from sea32-co-svc-lb4-vlan3.sea.corp.amazon.com (HELO email-inbound-relay-2b-baacba05.us-west-2.amazon.com) ([10.47.23.38]) by smtp-border-fw-out-33001.sea14.amazon.com with ESMTP; 17 Nov 2020 23:49:57 +0000 Received: from EX13MTAUWB001.ant.amazon.com (pdx1-ws-svc-p6-lb9-vlan2.pdx.amazon.com [10.236.137.194]) by email-inbound-relay-2b-baacba05.us-west-2.amazon.com (Postfix) with ESMTPS id 90E5DA1E01; Tue, 17 Nov 2020 23:49:55 +0000 (UTC) Received: from EX13D01UWB001.ant.amazon.com (10.43.161.75) by EX13MTAUWB001.ant.amazon.com (10.43.161.249) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 17 Nov 2020 23:49:54 +0000 Received: from EX13MTAUEB002.ant.amazon.com (10.43.60.12) by EX13d01UWB001.ant.amazon.com (10.43.161.75) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Tue, 17 Nov 2020 23:49:54 +0000 Received: from localhost (10.143.193.228) by mail-relay.amazon.com (10.43.60.234) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Tue, 17 Nov 2020 23:49:47 +0000 From: Balbir Singh To: , CC: , , , Balbir Singh Subject: [PATCH v1 2/3] Documentation: Update the new SIGBUS behaviour for tasks Date: Wed, 18 Nov 2020 10:49:33 +1100 Message-ID: <20201117234934.25985-3-sblbir@amazon.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201117234934.25985-1-sblbir@amazon.com> References: <20201117234934.25985-1-sblbir@amazon.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Update the documentation to mention that a SIGBUS will be sent to tasks that opt-into L1D flushing and execute on non-SMT cores. Signed-off-by: Balbir Singh --- To be applied on top of tip commit id 767d46ab566dd489733666efe48732d523c8c332 Documentation/admin-guide/hw-vuln/l1d_flush.rst | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/Documentation/admin-guide/hw-vuln/l1d_flush.rst b/Documentation/admin-guide/hw-vuln/l1d_flush.rst index adc4ecc72361..c6a0713c8271 100644 --- a/Documentation/admin-guide/hw-vuln/l1d_flush.rst +++ b/Documentation/admin-guide/hw-vuln/l1d_flush.rst @@ -63,8 +63,8 @@ This can be addressed by controlled placement of processes on physical CPU cores or by disabling SMT. See the relevant chapter in the L1TF mitigation document: :ref:`Documentation/admin-guide/hw-vuln/l1tf.rst `. -**NOTE** : Checks have been added to ensure that the prctl API associated +**NOTE** : Checks have been added to ensure that the L1D flush associated with the opt-in will work only when the task affinity of the task opting -in, is limited to cores running in non-SMT mode. The same checks are made -when L1D is flushed. Changing the affinity after opting in, would result -in flushes not working on cores that are in non-SMT mode. +in, is limited to cores running in non-SMT mode. Changing the affinity after +opting in, would result in the task getting a SIGBUS when it executes on +the flush is needed and the task is executing on the non-SMT core. -- 2.17.1