From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-pf1-f196.google.com ([209.85.210.196]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1h3iKz-00023d-4o for kexec@lists.infradead.org; Tue, 12 Mar 2019 14:25:07 +0000 Received: by mail-pf1-f196.google.com with SMTP id y124so958034pfy.7 for ; Tue, 12 Mar 2019 07:25:00 -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) 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 MIME-Version: 1.0 In-Reply-To: <20190311090553.GA12130@dhcp-128-65.nay.redhat.com> Content-Language: en-US List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Dave Young Cc: Mark Rutland , Kazuhito Hagio , Michael Ellerman , x86@kernel.org, Will Deacon , linux-kernel@vger.kernel.org, Ingo Molnar , Paul Mackerras , James Morse , Benjamin Herrenschmidt , Boris Petkov , Thomas Gleixner , bhupesh.linux@gmail.com, linuxppc-dev@lists.ozlabs.org, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, Dave Anderson 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 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec