lkml.org 
[lkml]   [2007]   [Aug]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 0/5] x86_64 EFI support -v3
From
Date
ebiederm@xmission.com (Eric W. Biederman) writes:
>
> Since there are people actively investigating things like booting
> OpenBSD via kexec things get even worse. Nothing hardly runs
> on ia64 so that issue doesn't come up.

If you want to do a popularity contest I expect there are far more ia64
linux users than kexec-of-openbsd users.

> As for not using EFI at all. If we can avoid it/not use it in the
> dump kernel there is very little point in having it in the primary
> kernel.

One interesting area is to use it for saving oops data. But
that has to be simple. I'm not sure complicated context switches
are a good idea here.

However I agree it probably doesn't make sense to do virtual
mode just for the clock services -- so far we seem to be fine
just talking to the hardware directly.

> So far there don't seem to be any compelling advantages to running
> EFI in virtual address mode and several compelling disadvantages
> included having to change the permissions on the kernels memory
> map to running EFI in virtual mode.

I don't think it's a big issue to have a few less NX bits. Just
the original patch for it was ugly.

> Please let's stick to a physical mode trampoline and only revisit
> the topic when users start having problems because of the performance
> hit of going through our trampoline to the EFI runtime services.

So you want to switch to new page tables when calling EFI services
after boot?

Potential problems:
- Interrupts have to be disabled. Is that ok?
- When EFI BIOS start crashing how do we set up exception handlers
for this?

I guess it would get complex long term. Also doesn't really sound
attractive.

-Andi
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-08-08 21:51    [from the cache]
©2003-2011 Jasper Spaans