* Re: [PATCH v3 03/13] arm64: improve CONFIG_STRICT_DEVMEM handling
[not found] ` <1416315432-8534-4-git-send-email-ard.biesheuvel@linaro.org>
@ 2014-11-25 17:39 ` Matt Fleming
2014-11-25 17:48 ` Borislav Petkov
0 siblings, 1 reply; 2+ messages in thread
From: Matt Fleming @ 2014-11-25 17:39 UTC (permalink / raw)
To: Ard Biesheuvel
Cc: leif.lindholm, roy.franz, linux-arm-kernel, mark.rutland, msalter,
dyoung, linux-efi, matt.fleming, will.deacon, catalin.marinas,
grant.likely, geoff.levand, linux-kernel, Borislav Petkov,
Peter Jones
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
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH v3 03/13] arm64: improve CONFIG_STRICT_DEVMEM handling
2014-11-25 17:39 ` [PATCH v3 03/13] arm64: improve CONFIG_STRICT_DEVMEM handling Matt Fleming
@ 2014-11-25 17:48 ` Borislav Petkov
0 siblings, 0 replies; 2+ messages in thread
From: Borislav Petkov @ 2014-11-25 17:48 UTC (permalink / raw)
To: Matt Fleming
Cc: Ard Biesheuvel, leif.lindholm, roy.franz, linux-arm-kernel,
mark.rutland, msalter, dyoung, linux-efi, matt.fleming,
will.deacon, catalin.marinas, grant.likely, geoff.levand,
linux-kernel, Peter Jones
On Tue, Nov 25, 2014 at 05:39:25PM +0000, Matt Fleming wrote:
> 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.
Yeah!
> Hooking this into the /dev/mem infrastructure just seems wrong to me.
And this virtmap.c thing is arm-only, AFAICT, but it looks like generic
code and like a wholly new way of doing the efi page table.
This thing needs to be properly split into generic pieces which go into
drivers/firmware/efi/ and arm-specific which would make that EFI_VIRTMAP
into an arch bit.
And so on and so on...
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
--
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2014-11-25 17:48 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
[not found] <1416315432-8534-1-git-send-email-ard.biesheuvel@linaro.org>
[not found] ` <1416315432-8534-4-git-send-email-ard.biesheuvel@linaro.org>
2014-11-25 17:39 ` [PATCH v3 03/13] arm64: improve CONFIG_STRICT_DEVMEM handling Matt Fleming
2014-11-25 17:48 ` Borislav Petkov
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox