On Wed, Feb 22, 2012 at 7:32 PM, H. Peter Anvin [off-list ref] wrote:

On 02/22/2012 06:20 PM, Yinghai Lu wrote:

quoted

Why is MAXMEM used here?

EFI reserved area could be above 4G?

if that is the case, you will map all mmio hole below 4g.

OK, dropping this patch for now, at least from -urgent.

We really need to restrict the memory types we map, at least without
ioremap() called on them.  In theory, on x86-64, we could have a
dedicated "1:1" address for each physical address, but there is no good
reason we should ever map memory types other than RAM, ACPI and EFI by
default -- with the possible exception of the low 1 MiB legacy area.

please check attach patch for tip/efi branch.

Thanks

       Yinghai