Re: [tip:x86/microcode] x86/microcode_intel_early.c: Early updateucode on Intel's CPU

[Yinghai Lu]

On Tue, Dec 11, 2012 at 9:38 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> On 12/11/2012 09:15 AM, Yinghai Lu wrote:
>>
>>
>> No, that is not right place. initrd could be loaded anywhere like way
>> high by bootloader.
>>
>
> Only *after* your changes... the current protocol doesn't allow that.

before for-x86-boot change,

bootloader put ramdisk just under 2g...

[    0.000000] memblock_reserve: [0x7d9dc000-0x7fffefff] RAMDISK

and arch/x86/kernel/head_64.S only set ident mapping for [0,1g)

so before init_memory_mapping, we need to use early_ioremap to access
ramdisk area.

also even after init_memory_mapping, we still need use early_ioremap to access
it because user could use memmap to skip it.

PS: this problem have nothing to do with mapping that is set by bootloader.
arch/x86/kernel/head_64.c will have it own mapping, and only cover [0,1g).

Yinghai

>
> Anyway, we need to deal with it, see below.
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