LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Rusty Russell <rusty@rustcorp.com.au>
To: Andi Kleen <ak@suse.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	virtualization@lists.osdl.org,
	lkml <linux-kernel@vger.kernel.org>
Subject: Re: [patch 4/6] Convert PDA into the percpu section
Date: Sat, 31 Mar 2007 12:54:17 +1000	[thread overview]
Message-ID: <1175309657.12230.420.camel@localhost.localdomain> (raw)
In-Reply-To: <200703310435.59298.ak@suse.de>

On Sat, 2007-03-31 at 04:35 +0200, Andi Kleen wrote:
> On Saturday 31 March 2007 04:00, Jeremy Fitzhardinge wrote:
> > Currently x86 (similar to x84-64) has a special per-cpu structure
> > called "i386_pda" which can be easily and efficiently referenced via
> > the %fs register.  An ELF section is more flexible than a structure,
> > allowing any piece of code to use this area.  Indeed, such a section
> > already exists: the per-cpu area.
> 
> Hmm, I'm a little reluctant. This moves i386 more away from x86-64
> again. If we ever merge them it would mean more work. Do you really need it?

Well, I think the merge should go the other way in this case: this
really does simplify things.

The only thing stopping x86-64 from doing the same as i386 is the
stack-protector stuff.  And that can be fixed (unfortunately requires a
gcc patch to change the %gs:40 to %gs:__gcc_stack_protector_offset and
emit a weak absolute symbol __gss_stack_protector_offset = 40).

I shall prepare a patch for that next week; I've been busy Kleening up
lguest 8)

Rusty.



  reply	other threads:[~2007-03-31  2:54 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-31  2:00 [patch 0/6] i386 gdt and percpu cleanups Jeremy Fitzhardinge
2007-03-31  2:00 ` [patch 1/6] i386: Account for module percpu space separately from kernel percpu Jeremy Fitzhardinge
2007-03-31  2:00 ` [patch 2/6] Allow percpu variables to be page-aligned Jeremy Fitzhardinge
2007-03-31  2:00 ` [patch 3/6] Page-align the GDT Jeremy Fitzhardinge
2007-03-31  2:00 ` [patch 4/6] Convert PDA into the percpu section Jeremy Fitzhardinge
2007-03-31  2:35   ` Andi Kleen
2007-03-31  2:54     ` Rusty Russell [this message]
2007-03-31  3:00     ` Jeremy Fitzhardinge
2007-03-31  2:00 ` [patch 5/6] cleanups to help using per-cpu variables from asm Jeremy Fitzhardinge
2007-03-31  2:00 ` [patch 6/6] Define per_cpu_offset Jeremy Fitzhardinge
2007-03-31  2:56 ` [patch 0/6] i386 gdt and percpu cleanups Rusty Russell
2007-03-31  3:05   ` Jeremy Fitzhardinge
2007-03-31  3:16 ` Jeremy Fitzhardinge

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1175309657.12230.420.camel@localhost.localdomain \
    --to=rusty@rustcorp.com.au \
    --cc=ak@suse.de \
    --cc=akpm@linux-foundation.org \
    --cc=jeremy@goop.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=virtualization@lists.osdl.org \
    --subject='Re: [patch 4/6] Convert PDA into the percpu section' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).