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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 4B78CC10F14 for ; Fri, 11 Oct 2019 00:54:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 274362053B for ; Fri, 11 Oct 2019 00:54:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727899AbfJKAyA (ORCPT ); Thu, 10 Oct 2019 20:54:00 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:3728 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727518AbfJKAx7 (ORCPT ); Thu, 10 Oct 2019 20:53:59 -0400 Received: from DGGEMS405-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id DAD81C24DE4D932AB452; Fri, 11 Oct 2019 08:53:57 +0800 (CST) Received: from [127.0.0.1] (10.177.223.23) by DGGEMS405-HUB.china.huawei.com (10.3.19.205) with Microsoft SMTP Server id 14.3.439.0; Fri, 11 Oct 2019 08:53:50 +0800 Subject: Re: [RFC PATCH 0/3] ACPI, arm64: Backport for ACPI PPTT 6.3 thread flag for stable 4.19.x To: John Garry , , , , , , , , , CC: , , , , , References: <1570714192-236724-1-git-send-email-john.garry@huawei.com> From: Hanjun Guo Message-ID: Date: Fri, 11 Oct 2019 08:53:32 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <1570714192-236724-1-git-send-email-john.garry@huawei.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.223.23] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi John, On 2019/10/10 21:29, John Garry wrote: > This series is a backport of the ACPI PPTT 6.3 thread flag feature for > supporting arm64 systems. > > The background is that some arm64 implementations are broken, in that they > incorrectly advertise that a CPU is mutli-threaded, when it is not - the > HiSilicon Taishanv110 rev 2, aka tsv110, being an example. > > This leads to the system topology being incorrect. The reason being that > arm64 topology code uses a combination of ACPI PPTT (Processor Properties > Topology Table) and the system MPIDR (Multiprocessor Affinity Register) MT > bit to determine the topology. > > Until ACPI 6.3, the PPTT did not have any method to determine whether > a CPU was multi-threaded, so only the MT bit is used - hence the > broken topology for some systems. > > In ACPI 6.3, a PPTT thread flag was introduced, which - when supported - > would be used by the kernel to determine really if a CPU is multi-threaded > or not, so that we don't get incorrect topology. Thanks for doing this, and this patch set fix my CPU topology issue in 4.19 kernel with updated firmware. > > Note: I'm sending this as an RFC before sending to stable proper. I also > have a 5.2 and 5.3 backport which are almost the same, and only > significant change being that the ACPICA patch is not required. 5.2 stable was end of life, so only 4.19 and 5.3 are needed I think. Thanks Hanjun