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Message-ID: <86802c440807090158p3728070cy2988beda20b451d4@mail.gmail.com>
Date: Wed, 9 Jul 2008 01:58:21 -0700
From: "Yinghai Lu" <yhlu.kernel@gmail.com>
To: "Ingo Molnar" <mingo@elte.hu>
Subject: Re: [PATCH] x86: not overmap than end in init_memory_mapping - 64bit
Cc: "Thomas Gleixner" <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
       LKML <linux-kernel@vger.kernel.org>
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On Wed, Jul 9, 2008 at 1:46 AM, Ingo Molnar <mingo@elte.hu> wrote:
>
> * Yinghai Lu <yhlu.kernel@gmail.com> 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