From 84779575554e2a19b9f6fc8d44f9763546a822ad Mon Sep 17 00:00:00 2001 From: "Lee, Chun-Yi" Date: Fri, 12 Sep 2014 11:03:58 +0800 Subject: [PATCH] x86/mm, hibernate: Do not assume the first e820 area to be RAM 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: e820: BIOS-provided physical RAM map: BIOS-e820: [mem 0x0000000000000000-0x0000000000096fff] usable BIOS-e820: [mem 0x0000000000097000-0x0000000000097fff] reserved ... e820: update [mem 0x00000000-0x00000fff] usable ==> reserved e820: remove [mem 0x000a0000-0x000fffff] usable But the region of first 4Kb didn't register to nosave memory: PM: Registered nosave memory: [mem 0x00097000-0x00097fff] PM: Registered nosave memory: [mem 0x000a0000-0x000fffff] The code 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. Signed-off-by: Lee, Chun-Yi Acked-by: Pavel Machek Cc: "Rafael J. Wysocki" Cc: Len Brown Cc: "H. Peter Anvin" Cc: Linus Torvalds Cc: Yinghai Lu Cc: Takashi Iwai Link: http://lkml.kernel.org/r/1410491038-17576-1-git-send-email-jlee@suse.com Signed-off-by: Ingo Molnar --- 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 988c00a1f60d..49f886481615 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -682,15 +682,14 @@ 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; + 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)) -- 2.34.1