Re: [RFC v2 0/2] Early use of boot service memory

jerry.hoemann
2013-11-21T23:31:15Z

On Thu, Nov 21, 2013 at 11:07:44PM +0000, Matthew Garrett wrote:
> On Thu, Nov 21, 2013 at 02:01:24PM -0700, Jerry Hoemann wrote:
> >
> > Some platform have firmware that violates the UEFI spec and access boot
> > service code or data segments after the system has called ExitBootServices().
> > The call to efi_reserve_boot_services in setup_arch is a workaround to
> > avoid using boot service memory until after the kernel has done
> > SetVirtualAddressMap. However, this reservation fragments memory
> > which can cause large allocations early in boot (e.g. crash kernel)
> > to fail.
>
> This is a problem we have to solve, but I don't think this is the right
> way to solve it. Why do we not just reattempt to perform the allocation
> immediately after we've freed the boot services regions?

Hi Matthew,

I tried this back on 3.11 kernel and reserve_crashkernel after free of
boot services failed. I will admit to not digging in too deeply as to
why it failed.

My earlier email:

https://lkml.org/lkml/2013/9/18/457

thanks

>
> --
> Matthew Garrett | mjg59@srcf.ucam.org

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