From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756720AbdDRMwD (ORCPT ); Tue, 18 Apr 2017 08:52:03 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:36041 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755700AbdDRMv6 (ORCPT ); Tue, 18 Apr 2017 08:51:58 -0400 Date: Tue, 18 Apr 2017 14:51:54 +0200 From: Ingo Molnar To: Baoquan He Cc: linux-kernel@vger.kernel.org, keescook@chromium.org, dave.jiang@intel.com, dan.j.williams@intel.com, hpa@zytor.com, tglx@linutronix.de, dyoung@redhat.com Subject: Re: [PATCH 0/4] Handle memmap and mem kernel options in boot stage kaslr Message-ID: <20170418125154.37rlz7ufb7bxukp4@gmail.com> References: <1492436099-4017-1-git-send-email-bhe@redhat.com> <20170418094753.q2siun6mkjoneqcn@gmail.com> <20170418113810.GA14395@x1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170418113810.GA14395@x1> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Baoquan He wrote: > On 04/18/17 at 11:47am, Ingo Molnar wrote: > > > > * 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. > > > > > > *) kernel-parameters.txt doesn't tell the updated behaviour of memmap=. > > > > > > This patchset tries to solve above issues. > > > > > > Baoquan He (4): > > > param: Move function next_arg to lib/cmdline.c for later reuse > > > KASLR: Parse all memmap entries in cmdline > > > KASLR: Handle memory limit specified by memmap and mem option > > > doc: Update description about memmap option in kernel-parameter.txt > > > > > > Documentation/admin-guide/kernel-parameters.txt | 9 ++ > > > arch/x86/boot/compressed/cmdline.c | 2 +- > > > arch/x86/boot/compressed/kaslr.c | 161 ++++++++++++++---------- > > > arch/x86/boot/string.c | 8 ++ > > > include/linux/kernel.h | 1 + > > > kernel/params.c | 52 -------- > > > lib/cmdline.c | 57 +++++++++ > > > 7 files changed, 172 insertions(+), 118 deletions(-) > > > > I ported this series to tip:x86/boot (please post future versions against that), > > and beyond a trivial conflict with e820entry => e820_entry, it fails to 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 > > > > ... which could be due to bad relocations, but I've not dug any further. > > Thanks, Ingo! > > I will find a x86_32 system to try allmodconfig. No need, on a 64-bit system just do: make ARCH=i386 allmodconfig and build the kernel the regular way. Thanks, Ingo