[PATCH v3 03/13] arm64: improve CONFIG_STRICT_DEVMEM handling

Matt Fleming matt at console-pimps.org
Tue Nov 25 09:39:25 PST 2014

On Tue, 18 Nov, at 01:57:02PM, Ard Biesheuvel wrote:
> Improve the handling of /dev/mem mappings under CONFIG_STRICT_DEVMEM by:
> - allowing read-only access to parts of System RAM that are not
>   considered memory by the kernel, this is mainly intended for exposing
>   UEFI Configuration tables to userland;
> - avoid using non-cached mappings for those parts of System RAM, as it
>   may result in mismatched attributes.

Is this really the best way to expose EFI config tables?

We already have parts in /sys/firmware/efi/ and in particular we expose
the runtime mappings there for kexec on x86.

Hooking this into the /dev/mem infrastructure just seems wrong to me.

Matt Fleming, Intel Open Source Technology Center

More information about the linux-arm-kernel mailing list