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=-8.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,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 1C502C10F13 for ; Tue, 16 Apr 2019 19:01:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E368A20663 for ; Tue, 16 Apr 2019 19:01:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="isnz1ZLC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730450AbfDPTBf (ORCPT ); Tue, 16 Apr 2019 15:01:35 -0400 Received: from mail.skyhub.de ([5.9.137.197]:45890 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727136AbfDPTBf (ORCPT ); Tue, 16 Apr 2019 15:01:35 -0400 Received: from zn.tnic (p200300EC2F0D6900BD7AE2FF560FC812.dip0.t-ipconnect.de [IPv6:2003:ec:2f0d:6900:bd7a:e2ff:560f:c812]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 0A8BA1EC05B8; Tue, 16 Apr 2019 21:01:33 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1555441293; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=F5xRbm9efINKQdR8vaSf/N5AR2hGc1XKPS/fdyAGySw=; b=isnz1ZLCe3k34ZVM8fwj0iZwiCxcFNi8cNzEzvV1UidVj88En5sftGMhySy13n+7TODJy9 tQQnl5WLpoDeoDRwJVPRgeEjhFrtUlKWaKZRb9mu3T/iROk+pX/C7IGAgSQeg8XPYoW8/i y6L0K+/ir5ND5LNY7OuvHy+74pLc1Ks= Date: Tue, 16 Apr 2019 21:01:28 +0200 From: Borislav Petkov To: Pingfan Liu Cc: x86@kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Baoquan He , Will Deacon , Nicolas Pitre , Vivek Goyal , Chao Fan , "Kirill A. Shutemov" , Ard Biesheuvel , Hari Bathini , linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 2/2] x86/boot/KASLR: skip the specified crashkernel region Message-ID: <20190416190128.GL31772@zn.tnic> References: <1554703115-15299-1-git-send-email-kernelfans@gmail.com> <1554703115-15299-3-git-send-email-kernelfans@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <1554703115-15299-3-git-send-email-kernelfans@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 08, 2019 at 01:58:35PM +0800, Pingfan Liu wrote: > crashkernel=x@y or or =range1:size1[,range2:size2,...]@offset option may > fail to reserve the required memory region if KASLR puts kernel into the > region. To avoid this uncertainty, asking KASLR to skip the required > region. > > Signed-off-by: Pingfan Liu > Cc: Thomas Gleixner > Cc: Ingo Molnar > Cc: Borislav Petkov > Cc: "H. Peter Anvin" > Cc: Baoquan He > Cc: Will Deacon > Cc: Nicolas Pitre > Cc: Vivek Goyal > Cc: Chao Fan > Cc: "Kirill A. Shutemov" > Cc: Ard Biesheuvel > CC: Hari Bathini > Cc: linux-kernel@vger.kernel.org > --- > arch/x86/boot/compressed/kaslr.c | 40 ++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 40 insertions(+) > > diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c > index 2e53c05..765a593 100644 > --- a/arch/x86/boot/compressed/kaslr.c > +++ b/arch/x86/boot/compressed/kaslr.c > @@ -107,6 +107,7 @@ enum mem_avoid_index { > MEM_AVOID_BOOTPARAMS, > MEM_AVOID_MEMMAP_BEGIN, > MEM_AVOID_MEMMAP_END = MEM_AVOID_MEMMAP_BEGIN + MAX_MEMMAP_REGIONS - 1, > + MEM_AVOID_CRASHKERNEL, > MEM_AVOID_MAX, > }; > > @@ -131,6 +132,11 @@ char *skip_spaces(const char *str) > } > #include "../../../../lib/ctype.c" > #include "../../../../lib/cmdline.c" > +#ifdef CONFIG_CRASH_CORE > +#define printk > +#define _BOOT_KASLR > +#include "../../../../lib/parse_crashkernel.c" > +#endif > > static int > parse_memmap(char *p, unsigned long long *start, unsigned long long *size) > @@ -292,6 +298,39 @@ static void handle_mem_options(void) > return; > } > > +static u64 mem_ram_size(void) > +{ > + struct boot_e820_entry *entry; > + u64 total_sz = 0; > + int i; > + > + for (i = 0; i < boot_params->e820_entries; i++) { > + entry = &boot_params->e820_table[i]; > + /* Skip non-RAM entries. */ > + if (entry->type != E820_TYPE_RAM) > + continue; > + total_sz += entry->size; > + } > + return total_sz; > +} > + > +/* > + * For crashkernel=size@offset or =range1:size1[,range2:size2,...]@offset > + * options, recording mem_avoid for them. > + */ > +static void handle_crashkernel_options(void) > +{ > + unsigned long long crash_size, crash_base = 0; > + char *cmdline = (char *)get_cmd_line_ptr(); > + u64 total_sz = mem_ram_size(); > + > + parse_crashkernel(cmdline, total_sz, &crash_size, &crash_base); That function has a return value which you could test. And then you don't need to set crash_base to 0 above. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.