Messages in this thread Patch in this message | | | Date | Tue, 9 Sep 2014 23:08:45 -0700 | Subject | Re: [PATCH] Hibernate: Do not assume the first e820 area to be RAM | From | Yinghai Lu <> |
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On Mon, Sep 8, 2014 at 3:52 PM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > 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" <rjw@rjwysocki.net> >> Cc: Len Brown <len.brown@intel.com> >> Cc: Pavel Machek <pavel@ucw.cz> >> Cc: Thomas Gleixner <tglx@linutronix.de> >> Cc: Ingo Molnar <mingo@redhat.com> >> Cc: "H. Peter Anvin" <hpa@zytor.com> >> Signed-off-by: Lee, Chun-Yi <jlee@suse.com> > > Thomas, Ingo, Peter, any objections here? > > If not, do you want to handle it or do you want me to do that?
Did it address any regression?
> >> --- >> 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));
could avoid the i > 0 checking.
>> >> pfn = PFN_DOWN(ei->addr + ei->size); >> >
following would be better ?
@@ -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))
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