From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422754AbdD0T5f (ORCPT ); Thu, 27 Apr 2017 15:57:35 -0400 Received: from mail-qk0-f194.google.com ([209.85.220.194]:35162 "EHLO mail-qk0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966059AbdD0T52 (ORCPT ); Thu, 27 Apr 2017 15:57:28 -0400 Subject: Re: [PATCH v3 0/3] Handle memmap and mem kernel options in boot stage kaslr To: Baoquan He , mingo@kernel.org, linux-kernel@vger.kernel.org References: <1493201772-19084-1-git-send-email-bhe@redhat.com> Cc: keescook@chromium.org, dyoung@redhat.com, douly.fnst@cn.fujitsu.com, dan.j.williams@intel.com From: YASUAKI ISHIMATSU Message-ID: Date: Thu, 27 Apr 2017 15:57:25 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <1493201772-19084-1-git-send-email-bhe@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Baoquan, On 04/26/2017 06:16 AM, Baoquan He wrote: > People reported kernel panic occurs during system boots up with mem boot option. > After checking code, several problems are found about memmap= and mem= in boot stage > kaslr. > > *) In commit f28442497b5c ("x86/boot: Fix KASLR and memmap= collision"), only one memmap > entry is considered and only the last one if multiple memmap entries are specified. > > *) mem= and memmap=nn[KMG] are not considered yet. They are used to limit max address > of system. Kernel can't be randomized to be above the limit. I confirmed that mem= works correctly. Tested-by: Yasuaki Ishimatsu Thanks, Yasuaki Ishimatsu > > *) kernel-parameters.txt doesn't tell the updated behaviour of memmap=. > > This patchset tries to solve above issues, and it sits on top of > tip:x86/boot branch. > > Changelog > > v2->v3: > No functionality change in this round. > a)Use local static variable insted of global variable > mem_avoid_memmap_index in patch 1/3. > b)Fix a typo in patch 3/3. > > v1->v2: > a)The original patch 1/4 has been put in tip:x86/boot and no update, > so it's not included in this post. > b)Use patch log Ingo reorganized. > c)lib/ctype.c and lib/cmdline.c are needed for kaslr.c, while those > EXPORT_SYMBOL(x) contained caused failure of build on 32-bit allmodconfig: > ...... > ld: -r and -shared may not be used together > scripts/Makefile.build:294: recipe for target 'arch/x86/boot/compressed/kaslr.o' failed > ...... > Disabling the symbol exporting removes the build failure. > d)Use dynamic allocation to allocate memory to contain copied kernel cmdline > buffer, it's implemented in include/linux/decompress/mm.h. > > > > Baoquan He (3): > KASLR: Parse all memmap entries in cmdline > KASLR: Handle memory limit specified by memmap and mem option > Documentation/kernel-parameters.txt: Update 'memmap=' option > description > > Documentation/admin-guide/kernel-parameters.txt | 9 ++ > arch/x86/boot/compressed/cmdline.c | 2 +- > arch/x86/boot/compressed/kaslr.c | 183 +++++++++++++++--------- > arch/x86/boot/string.c | 8 ++ > 4 files changed, 136 insertions(+), 66 deletions(-) >