Re: [PATCH] Fix e820 end address with EFI

[Yinghai Lu]

On Sat, Feb 28, 2009 at 8:26 AM, Brian Maly <bmaly@xxxxxxxxxx> wrote:
>
>   On some EFI systems (i.e. Apple) EFI runtime is mapped into higher mem
> regions. These EFI mem regions are not always taken into consideration when
> max_pfn is calculated in setup.c being that e820_end_of_ram_pfn() only
> counts
> mappings types marked as usable (E820_RAM). Currently we only count to the
> last
> usable e820 address range and nothing beyond. EFI can be mapped anywhere
> within
> e820 and is not always marked as usable e820, and so EFI runtime may be
> missed
> if mapped somewhere beyond last usable e820. This patch attempts to resolve
> this problem by including all E820 mappings when EFI is enabled, so that
> the entire e820 (and EFI runtime area) is included in computing max_pfn.
> Tested
> on a MacBook Pro 3.1 and resolves the issue (system now boots w/elilo+grub &
> EFI).
>

it seems you should check and enable directly mapping when EFI runtime
service is enabled.

YH
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