Re: [PATCH] x86: not overmap than end in init_memory_mapping - 64bit

[Yinghai Lu]

On Wed, Jul 9, 2008 at 1:46 AM, Ingo Molnar <mingo@xxxxxxx> wrote:
>
> * Yinghai Lu <yhlu.kernel@xxxxxxxxx> wrote:
>
>> > reverting the commit solves the crash. The crash seems to be because
>> > ACPI is unable to access that memory range. (perhaps early_ioremap
>> > fails?)
>>
>> system with less than 4g?
>
> yeah.
>
>> please test attached patch
>> [PATCH] x86: make max_pfn cover acpi table below 4g
>
> that fixed it, thanks.

[    0.000000] kernel direct mapping tables up to 3fff0000 @ 8000-b000
[    0.000000] last_map_addr: 40000000 end: 3fff0000
[    0.000000] ACPI: RSDP 000F76F0, 0014 (r0 Nvidia)

last_map_addr is supposed to be 3fff0000.

so it means before init_memory_mapping, initial page table already
cover to 0x40000000 with 2M big page.
and init_memory_mapping can not do anything with that is already mapped.

it seems that need to make early_ioremap more smart...

YH
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