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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 54934C43381 for ; Tue, 12 Mar 2019 14:25:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 271812075C for ; Tue, 12 Mar 2019 14:25:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726744AbfCLOZB (ORCPT ); Tue, 12 Mar 2019 10:25:01 -0400 Received: from mail-pg1-f196.google.com ([209.85.215.196]:38680 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726325AbfCLOZB (ORCPT ); Tue, 12 Mar 2019 10:25:01 -0400 Received: by mail-pg1-f196.google.com with SMTP id m2so1960669pgl.5 for ; Tue, 12 Mar 2019 07:25:00 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=JVtjTgwXpS+F36W6pTKl2sgAGbR0g7swMsIvnMxPdXI=; b=FrqKcK5UQbRetI4kfOSDeNCZFax6XfnJnYwVrmb25lLyvFTwqCaUgBkw5amzH+qGnn r5ngABdKM3VoPka6wfXgupi3u/kyZ3Fv48H0X/djPVdXouHc0yM+d7j4x9U+trs+K94m CdlSBZ2Kt8JmpPYpoLHeHuX+y+u8xwmcoMCD36s6wqKKUPcu7HTxr36/S0PGyc0Onubj yUmDvciWY/kF/gSp9LMVeS3r+Mc8bwiEq7o7Nxu7C+ho7fCiWHCpsKM88MhfUszahQiR aeylr+yV11XFJYapO3g0IbC3BL3QK3PfFQdYSRnc3VEtMVx9i+MkM0xVYIMl41TmvxSu VhdQ== X-Gm-Message-State: APjAAAXGTNJOnusa+/bPNz+2URaFXaxFZ2VXQ7WfG5ezw+X4pgsqHTC4 8eeJ7nNykv9GusyqhIFbY0xT0A== X-Google-Smtp-Source: APXvYqy/lZGxY05IxZmj/bjio5X3k/2VTVwc6tTbffOlATD8kE0l5KCBmKSisZ7AgbuRRARTZhJkfA== X-Received: by 2002:aa7:8c97:: with SMTP id p23mr39726199pfd.229.1552400699994; Tue, 12 Mar 2019 07:24:59 -0700 (PDT) Received: from localhost.localdomain ([106.215.118.61]) by smtp.gmail.com with ESMTPSA id z15sm16451189pgc.25.2019.03.12.07.24.52 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 12 Mar 2019 07:24:58 -0700 (PDT) Subject: Re: [PATCH v2 0/2] Append new variables to vmcoreinfo (PTRS_PER_PGD for arm64 and MAX_PHYSMEM_BITS for all archs) To: Dave Young Cc: linux-kernel@vger.kernel.org, Mark Rutland , Kazuhito Hagio , Michael Ellerman , x86@kernel.org, Will Deacon , linuxppc-dev@lists.ozlabs.org, kexec@lists.infradead.org, James Morse , linux-arm-kernel@lists.infradead.org, Benjamin Herrenschmidt , Boris Petkov , Thomas Gleixner , bhupesh.linux@gmail.com, Dave Anderson , Ingo Molnar , Paul Mackerras References: <1552212242-9479-1-git-send-email-bhsharma@redhat.com> <20190311090553.GA12130@dhcp-128-65.nay.redhat.com> From: Bhupesh Sharma Message-ID: <409a4754-0d01-6eab-2524-94d88bbc609b@redhat.com> Date: Tue, 12 Mar 2019 19:54:49 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <20190311090553.GA12130@dhcp-128-65.nay.redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Dave, On 03/11/2019 02:35 PM, Dave Young wrote: > Hi Bhupesh, > On 03/10/19 at 03:34pm, Bhupesh Sharma wrote: >> Changes since v1: >> ---------------- >> - v1 was sent out as a single patch which can be seen here: >> http://lists.infradead.org/pipermail/kexec/2019-February/022411.html >> >> - v2 breaks the single patch into two independent patches: >> [PATCH 1/2] appends 'PTRS_PER_PGD' to vmcoreinfo for arm64 arch, whereas >> [PATCH 2/2] appends 'MAX_PHYSMEM_BITS' to vmcoreinfo in core kernel code (all archs) >> >> This patchset primarily fixes the regression reported in user-space >> utilities like 'makedumpfile' and 'crash-utility' on arm64 architecture >> with the availability of 52-bit address space feature in underlying >> kernel. These regressions have been reported both on CPUs which don't >> support ARMv8.2 extensions (i.e. LVA, LPA) and are running newer kernels >> and also on prototype platforms (like ARMv8 FVP simulator model) which >> support ARMv8.2 extensions and are running newer kernels. >> >> The reason for these regressions is that right now user-space tools >> have no direct access to these values (since these are not exported >> from the kernel) and hence need to rely on a best-guess method of >> determining value of 'PTRS_PER_PGD' and 'MAX_PHYSMEM_BITS' supported >> by underlying kernel. >> >> Exporting these values via vmcoreinfo will help user-land in such cases. >> In addition, as per suggestion from makedumpfile maintainer (Kazu) >> during v1 review, it makes more sense to append 'MAX_PHYSMEM_BITS' to >> vmcoreinfo in the core code itself rather than in arm64 arch-specific >> code, so that the user-space code for other archs can also benefit from >> this addition to the vmcoreinfo and use it as a standard way of >> determining 'SECTIONS_SHIFT' value in user-land. >> >> Cc: Mark Rutland >> Cc: James Morse >> Cc: Will Deacon >> Cc: Boris Petkov >> Cc: Ingo Molnar >> Cc: Thomas Gleixner >> Cc: Michael Ellerman >> Cc: Paul Mackerras >> Cc: Benjamin Herrenschmidt >> Cc: Dave Anderson >> Cc: Kazuhito Hagio >> Cc: x86@kernel.org >> Cc: linuxppc-dev@lists.ozlabs.org >> Cc: linux-arm-kernel@lists.infradead.org >> Cc: linux-kernel@vger.kernel.org >> Cc: kexec@lists.infradead.org >> >> Bhupesh Sharma (2): >> arm64, vmcoreinfo : Append 'PTRS_PER_PGD' to vmcoreinfo >> crash_core, vmcoreinfo: Append 'MAX_PHYSMEM_BITS' to vmcoreinfo >> >> arch/arm64/kernel/crash_core.c | 1 + >> kernel/crash_core.c | 1 + >> 2 files changed, 2 insertions(+) >> > > Lianbo's document patch has been merged, would you mind to add vmcoreinfo doc > patch as well in your series? Thanks for the inputs. Will add it to the v3. Let's wait for other comments/reviews, before I spin a version 3. Regards, Bhupesh