On Mon, Sep 8, 2014 at 3:52 PM, Rafael J. Wysocki <r...@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" <r...@rjwysocki.net>
>> Cc: Len Brown <len.br...@intel.com>
>> Cc: Pavel Machek <pa...@ucw.cz>
>> Cc: Thomas Gleixner <t...@linutronix.de>
>> Cc: Ingo Molnar <mi...@redhat.com>
>> Cc: "H. Peter Anvin" <h...@zytor.com>
>> Signed-off-by: Lee, Chun-Yi <j...@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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