From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753490AbaILDET (ORCPT ); Thu, 11 Sep 2014 23:04:19 -0400 Received: from mail-pa0-f53.google.com ([209.85.220.53]:39170 "EHLO mail-pa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752168AbaILDER (ORCPT ); Thu, 11 Sep 2014 23:04:17 -0400 From: "Lee, Chun-Yi" X-Google-Original-From: "Lee, Chun-Yi" To: "Rafael J. Wysocki" , Len Brown , Pavel Machek Cc: Takashi Iwai , Yinghai Lu , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, "Lee, Chun-Yi" , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Subject: [PATCH v2] Hibernate: Do not assume the first e820 area to be RAM Date: Fri, 12 Sep 2014 11:03:58 +0800 Message-Id: <1410491038-17576-1-git-send-email-jlee@suse.com> X-Mailer: git-send-email 1.8.4.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. v2: To avoid the i > 0 checking in for loop. (coding suggestion from Yinghai Lu) Cc: "Rafael J. Wysocki" Cc: Len Brown Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Yinghai Lu Acked-by: Pavel Machek Signed-off-by: Lee, Chun-Yi --- arch/x86/kernel/e820.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) Index: linux-3.12-SLE12/arch/x86/kernel/e820.c =================================================================== --- linux-3.12-SLE12.orig/arch/x86/kernel/e820.c +++ linux-3.12-SLE12/arch/x86/kernel/e820.c @@ -682,15 +682,14 @@ void __init parse_e820_ext(u64 phys_addr * 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; + unsigned long pfn = 0; - 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))