From: hpa@zytor.com (H. Peter Anvin)
To: linux-kernel@vger.kernel.org
Subject: Re: [CFT][PATCH] 2.6.4-rc1 remove x86 boot page tables
Date: Tue, 2 Mar 2004 06:47:53 +0000 (UTC) [thread overview]
Message-ID: <c21amp$769$1@terminus.zytor.com> (raw)
In-Reply-To: m1vflp81kq.fsf@ebiederm.dsl.xmission.com
Followup to: <m1vflp81kq.fsf@ebiederm.dsl.xmission.com>
By author: ebiederm@xmission.com (Eric W. Biederman)
In newsgroup: linux.dev.kernel
>
> I think I have accounted for the sub architectures but I don't have
> the hardware to test them. For voyager and VISWS I actually changed
> some code so I would appreciate a confirmation I didn't break
> anything.
>
For VISWS I think you actually need to turn paging off explicitly.
Also, you probably need to check that you didn't break 4G/4G,
especially on SMP.
I would also like to remove the magic %bx, which I did in the version
of my patch sent to akpm and which is now in -mm (basically the SMP
trampoline jumps to a different entrypoint instead.) In that patch,
%ebx is still used as a flag, but it's completely internal to head.S.
See ftp://ftp.kernel.org/pub/linux/kernel/people/hpa/earlymem-7.diff
> Thanks to HPA who got the ball started :)
:)
I definitely agree that simply using no paging until we have page
tables is by far the cleanest approach. I felt that is was too high
risk for 2.6, basically because I'm a chicken, but more realistically
because I couldn't really see the effect on all subarchitectures, and
I didn't feel 100% confident that there wasn't anything that relied on
memory being dual mapped; however, I'm more than happy to be proven
wrong :)
Oh yes, with this change you should probably just move swapper_pg_dir
(and empty_zero_page?) into .bss like anything else that should be
zero after boot.
-hpa
next prev parent reply other threads:[~2004-03-02 6:48 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-01 7:32 [CFT][PATCH] 2.6.4-rc1 remove x86 boot page tables Eric W. Biederman
2004-03-01 19:05 ` Dave Hansen
2004-03-02 5:29 ` Eric W. Biederman
2004-03-02 6:47 ` H. Peter Anvin [this message]
2004-03-02 12:53 ` [PATCH] Clean up empty_zero_page abuse Brian Gerst
2004-03-02 17:56 ` [CFT][PATCH] 2.6.4-rc1 remove x86 boot page tables Eric W. Biederman
2004-03-02 9:21 ` H. Peter Anvin
-- strict thread matches above, loose matches on Subject: below --
2004-03-01 18:13 Tolentino, Matthew E
2004-03-02 5:36 ` Eric W. Biederman
2004-03-03 6:47 ` Eric W. Biederman
2004-03-03 8:15 ` Eric W. Biederman
2004-03-03 19:45 Tolentino, Matthew E
2004-03-05 14:23 ` Eric W. Biederman
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