From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755446AbaIHWdb (ORCPT ); Mon, 8 Sep 2014 18:33:31 -0400 Received: from v094114.home.net.pl ([79.96.170.134]:60861 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754936AbaIHWd3 (ORCPT ); Mon, 8 Sep 2014 18:33:29 -0400 From: "Rafael J. Wysocki" To: "Lee, Chun-Yi" , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Cc: Len Brown , Pavel Machek , Takashi Iwai , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, "Lee, Chun-Yi" Subject: Re: [PATCH] Hibernate: Do not assume the first e820 area to be RAM Date: Tue, 09 Sep 2014 00:52:55 +0200 Message-ID: <1561567.ev2pEO8C5v@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/3.16.0-rc5+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <1407754252-22779-1-git-send-email-jlee@suse.com> References: <1407754252-22779-1-git-send-email-jlee@suse.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday, August 11, 2014 06:50:52 PM Lee, Chun-Yi wrote: > In arch/x86/kernel/setup.c::trim_bios_range(), the codes introduced > by 1b5576e6 (base on d8a9e6a5), it updates the first 4Kb of memory > to be E820_RESERVED region. That's because it's a BIOS owned area > but generally not listed in the E820 table: > > [ 0.000000] e820: BIOS-provided physical RAM map: > [ 0.000000] BIOS-e820: [mem 0x0000000000000000-0x0000000000096fff] usable > [ 0.000000] BIOS-e820: [mem 0x0000000000097000-0x0000000000097fff] reserved > ... > [ 0.000000] e820: update [mem 0x00000000-0x00000fff] usable ==> reserved > [ 0.000000] e820: remove [mem 0x000a0000-0x000fffff] usable > > But the region of first 4Kb didn't register to nosave memory: > > [ 0.000000] PM: Registered nosave memory: [mem 0x00097000-0x00097fff] > [ 0.000000] PM: Registered nosave memory: [mem 0x000a0000-0x000fffff] > > The codes in e820_mark_nosave_regions() assumes the first e820 area to be > RAM, so it causes the first 4Kb E820_RESERVED region ignored when register > to nosave. This patch removed assumption of the first e820 area. > > Cc: "Rafael J. Wysocki" > Cc: Len Brown > Cc: Pavel Machek > Cc: Thomas Gleixner > Cc: Ingo Molnar > Cc: "H. Peter Anvin" > Signed-off-by: Lee, Chun-Yi Thomas, Ingo, Peter, any objections here? If not, do you want to handle it or do you want me to do that? > --- > arch/x86/kernel/e820.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c > index 988c00a..d595240 100644 > --- a/arch/x86/kernel/e820.c > +++ b/arch/x86/kernel/e820.c > @@ -682,18 +682,17 @@ void __init parse_e820_ext(u64 phys_addr, u32 data_len) > * hibernation (32 bit) or software suspend and suspend to RAM (64 bit). > * > * This function requires the e820 map to be sorted and without any > - * overlapping entries and assumes the first e820 area to be RAM. > + * overlapping entries. > */ > void __init e820_mark_nosave_regions(unsigned long limit_pfn) > { > int i; > unsigned long pfn; > > - pfn = PFN_DOWN(e820.map[0].addr + e820.map[0].size); > - for (i = 1; i < e820.nr_map; i++) { > + for (i = 0; i < e820.nr_map; i++) { > struct e820entry *ei = &e820.map[i]; > > - if (pfn < PFN_UP(ei->addr)) > + if (i > 0 && pfn < PFN_UP(ei->addr)) > register_nosave_region(pfn, PFN_UP(ei->addr)); > > pfn = PFN_DOWN(ei->addr + ei->size); > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.