Subject: [PATCH v2 1/2] efi: esrt: use memremap not ioremap to access ESRT table in memory

From: [email-masked] (Matt Fleming)
Date: Thu, 18 Feb 2016 14:38:25 +0000

On Thu, 18 Feb, at 03:21:25PM, Ard Biesheuvel wrote:
> 
> We treat all Boot Services regions like Loader Code/Data or free
> regions: it is all recorded in memblock as usable memory, and only the
> regions that are explicitly reserved are protected from further
> general use.
> 
> I am currently looking into the memory attribute table, and the use
> case is very similar. It would be very useful from our pov to simply
> memblock_reserve() the region right after having called
> efi_config_parse_tables(), and actually consume its data when we get
> around to it later. The ESRT handling is already split down the middle
> in the same way.

Agreed, this would also be useful in general for kexec. I've got a
couple of patches in flight that try to handle the BGRT case in a
different way,

  https://lkml.kernel.org/r/1455723910-16710-2-git-send-email-matt at codeblueprint.co.uk
  https://lkml.kernel.org/r/1455723910-16710-3-git-send-email-matt at codeblueprint.co.uk

Let me instead take a look at how we might be able to preserve only
those Boot Services regions we care out.