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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT 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 0D88AC4360F for ; Wed, 3 Apr 2019 08:23:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CE55A2084C for ; Wed, 3 Apr 2019 08:23:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728861AbfDCIXM (ORCPT ); Wed, 3 Apr 2019 04:23:12 -0400 Received: from mail.cn.fujitsu.com ([183.91.158.132]:25154 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726004AbfDCIXM (ORCPT ); Wed, 3 Apr 2019 04:23:12 -0400 X-IronPort-AV: E=Sophos;i="5.60,303,1549900800"; d="scan'208";a="58373655" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 03 Apr 2019 16:23:09 +0800 Received: from G08CNEXCHPEKD01.g08.fujitsu.local (unknown [10.167.33.80]) by cn.fujitsu.com (Postfix) with ESMTP id 35F954C8B03D; Wed, 3 Apr 2019 16:23:11 +0800 (CST) Received: from localhost.localdomain (10.167.225.56) by G08CNEXCHPEKD01.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server (TLS) id 14.3.439.0; Wed, 3 Apr 2019 16:23:15 +0800 Date: Wed, 3 Apr 2019 16:23:06 +0800 From: Chao Fan To: Dave Young CC: Junichi Nomura , Borislav Petkov , "bhe@redhat.com" , "kasong@redhat.com" , "x86@kernel.org" , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v2] x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernel Message-ID: <20190403082305.GG1555@localhost.localdomain> References: <73322ba9-e436-68db-7863-afd31607d969@ce.jp.nec.com> <20190328064343.GA1877@MiWiFi-R3L-srv> <20190328074337.GA9470@jeru.linux.bs1.fc.nec.co.jp> <20190328155256.GP22720@zn.tnic> <20190401000837.GA5170@jeru.linux.bs1.fc.nec.co.jp> <20190402120319.GA7605@dhcp-128-65.nay.redhat.com> <20190403053459.GD1555@localhost.localdomain> <20190403055340.GA11976@dhcp-128-65.nay.redhat.com> <20190403072141.GE1555@localhost.localdomain> <20190403080846.GB2579@dhcp-128-65.nay.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <20190403080846.GB2579@dhcp-128-65.nay.redhat.com> User-Agent: Mutt/1.11.3 (2019-02-01) X-Originating-IP: [10.167.225.56] X-yoursite-MailScanner-ID: 35F954C8B03D.ACA1F X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: fanc.fnst@cn.fujitsu.com Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 03, 2019 at 04:09:16PM +0800, Dave Young wrote: >On 04/03/19 at 03:21pm, Chao Fan wrote: >> On Wed, Apr 03, 2019 at 01:53:40PM +0800, Dave Young wrote: >> >On 04/03/19 at 01:35pm, Chao Fan wrote: >> >> On Tue, Apr 02, 2019 at 08:03:19PM +0800, Dave Young wrote: >> >> >On 04/01/19 at 12:08am, Junichi Nomura wrote: >> >> >> Commit 3a63f70bf4c3a ("x86/boot: Early parse RSDP and save it in >> >> >> boot_params") broke kexec boot on EFI systems. efi_get_rsdp_addr() >> >> >> in the early parsing code tries to search RSDP from EFI table but >> >> >> that will crash because the table address is virtual when the kernel >> >> >> was booted by kexec. >> >> >> >> >> >> In the case of kexec, physical address of EFI tables is provided >> >> >> via efi_setup_data in boot_params, which is set up by kexec(1). >> >> >> >> >> >> Factor out the table parsing code and use different pointers depending >> >> >> on whether the kernel is booted by kexec or not. >> >> >> >> >> >> Fixes: 3a63f70bf4c3a ("x86/boot: Early parse RSDP and save it in boot_params") >> >> >> Signed-off-by: Jun'ichi Nomura >> >> >> Acked-by: Baoquan He >> >> >> Cc: Chao Fan >> >> >> Cc: Borislav Petkov >> >> >> Cc: Dave Young >> >> [...] >> >> > >> >> >I failed to kexec reboot on my laptop, kernel panics too quick, I'm not sure this is >> >> >caused by your patch though. >> >> > >> >> >Actually there are something probably i915 changes break kexec, the >> >> >above test is with "nomodeset" which should work. >> >> > >> >> >Let me do more testing and update here tomorrow. >> >> > >> >> >> >> Hi Dave, >> >> >> >> Last day I was testing the normal kexec, today I have tested the kdump >> >> issue. Since the kdump has set "nokaslr" to cmdline, so I drop from >> >> KDUMP_COMMANDLINE_APPEND >> >> And it booted OK, so the PATCH works in both normal kexec and kdump. >> >> >> > >> >Actually I got some different kexec test results. >> > >> >Yesterday, with my installed kernel (based on git head several weeks >> >ago), kexec kernel panics. >> > >> >Then I tried latest mainline with git pull, everything works, (with or >> >without the patch, and can not reproduce the bug this patch is fixing) >> > >> >Today, test again, kexec reboot hangs (with or without your patch), but >> >kdump works always (with or without the patch) >> >> That's so strange, I'm puzzled by your test. >> Withour ant changes, just test again, the result of yesterday and today >> are different? >> >> > >> >It is weird to me. Probably I need find out why I can not reproduce the >> >bug this patch is addressing first. >> >> Hmm, is your laptop booted from EFI or legacy BIOS? > >EFI booted. > >> > >> >earlyprintk seems not working for me anymore, it is not easy to debug on >> >laptop now. >> >> Another computer can help print the console message. >> I remeber you are good at debug on two computers. > >I used to use earlyprintk, but seems earlyprintk can not work so early. >So I only can try to comment out code manually. Ah, I got it. If you want to use earlyprintk to print message of get_rsdp_addr(), you should change some code. Because get_rsdp_addr() is called before earlyprintk initialed. I am still testing, but in my debug stage, I change like this: diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index c0d6c560df69..dbbe8d9a5792 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -352,7 +352,6 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap, boot_params->hdr.loadflags &= ~KASLR_FLAG; /* Save RSDP address for later use. */ - boot_params->acpi_rsdp_addr = get_rsdp_addr(); sanitize_boot_params(boot_params); @@ -368,6 +367,7 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap, cols = boot_params->screen_info.orig_video_cols; console_init(); + boot_params->acpi_rsdp_addr = get_rsdp_addr(); debug_putstr("early console in extract_kernel\n"); free_mem_ptr = heap; /* Heap */ Call this function after console_init(). That will make earlyprintk works. > >It seems to be still some bug in early acpi code because if I >return 0 in get rsdp function it just works. > >This guess make sense to me for now: >1. nokaslr does not work because it may only avoid randomization, but it >does not avoid running the early acpi parsing code. > >2. kexec does not work without the patch we talked about, because I just >reproduced Junichi reported bug, sometimes hang, or reset, it is >understandable. > >3. kexec does not work with the patch, so there is still bugs in the >code. > >So several things to do is: > >Fix 1. (separate issue), Baoquan or either of you may want to fix it :) For 1, I think it's not needed to fix. Since not only KASLR needs RSDP. So nokaslr should not stop the acpi parsing code. > >Fix 3. need more debugging, have you or Junichi run tests on more real >hardware, maybe it is easier to reproduce on real hardware, I'm glad to >help to try test patch or provide any help. I am still testing in real hardware. Thanks, Chao Fan > >Thanks >Dave > >