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" <r...@rjwysocki.net> Cc: Len Brown <len.br...@intel.com> Cc: Thomas Gleixner <t...@linutronix.de> Cc: Ingo Molnar <mi...@redhat.com> Cc: "H. Peter Anvin" <h...@zytor.com> Cc: Yinghai Lu <ying...@kernel.org> Acked-by: Pavel Machek <pa...@ucw.cz> Signed-off-by: Lee, Chun-Yi <j...@suse.com> --- 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)) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/