From: "H. Peter Anvin" <hpa@zytor.com>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Christoph Lameter <clameter@sgi.com>,
Mike Travis <travis@sgi.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [crash, bisected] Re: [PATCH 3/4] x86_64: Fold pda into per cpu area
Date: Fri, 20 Jun 2008 12:21:37 -0700 [thread overview]
Message-ID: <485C0341.3090302@zytor.com> (raw)
In-Reply-To: <485BFF57.5090906@goop.org>
Jeremy Fitzhardinge wrote:
>>
>> Its loaded at __per_cpu_load but the symbols have addresses starting
>> at 0.
>
> Yes, which leads to an odd-looking ELF file where the Phdrs aren't
> sorted by virtual address order. I'm wondering what would happen if a
> bootloader that actually understood ELF files tried to load it as an
> actual ELF file...
>
If it is implemented correctly, it will work. It might trigger bugs in
such loaders, however.
>> Hmmm.... we could add the relocation offset to __per_cpu_load?
>> __per_cpu_load is used very sparingly. Basically only useful during
>> early boot and when a new per cpu area has to be setup. In that case
>> we want to copy from __per_cpu_load to the newly allocated percpu area.
>
> Yes, it should be fairly easy to manually relocate it by applying the
> (load - link) offset to it.
Seems easy enough, and as already stated, this is not
performance-critical so a few extra instructions is pretty much a non-issue.
-hpa
next prev parent reply other threads:[~2008-06-20 19:25 UTC|newest]
Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-04 0:30 [PATCH 0/4] percpu: Optimize percpu accesses Mike Travis
2008-06-04 0:30 ` [PATCH 1/4] Zero based percpu: Infrastructure to rebase the per cpu area to zero Mike Travis
2008-06-10 10:06 ` Ingo Molnar
2008-06-04 0:30 ` [PATCH 2/4] x86: Extend percpu ops to 64 bit Mike Travis
2008-06-10 10:04 ` Ingo Molnar
2008-06-04 0:30 ` [PATCH 3/4] x86_64: Fold pda into per cpu area Mike Travis
2008-06-04 12:59 ` Jeremy Fitzhardinge
2008-06-04 13:48 ` Mike Travis
2008-06-04 13:58 ` Jeremy Fitzhardinge
2008-06-04 14:17 ` Mike Travis
2008-06-09 23:18 ` Christoph Lameter
2008-06-05 10:22 ` [crash, bisected] " Ingo Molnar
2008-06-05 16:02 ` Mike Travis
2008-06-06 8:29 ` Jeremy Fitzhardinge
2008-06-06 13:15 ` Mike Travis
2008-06-18 5:34 ` Jeremy Fitzhardinge
2008-06-10 21:31 ` Mike Travis
2008-06-18 17:36 ` Jeremy Fitzhardinge
2008-06-18 18:17 ` Mike Travis
2008-06-18 18:33 ` Ingo Molnar
2008-06-18 19:33 ` Jeremy Fitzhardinge
[not found] ` <48596893.4040908@sgi.com>
[not found] ` <485AADAC.3070301@sgi.com>
[not found] ` <485AB78B.5090904@goop.org>
[not found] ` <485AC120.6010202@sgi.com>
[not found] ` <485AC5D4.6040302@goop.org>
[not found] ` <485ACA8F.10006@sgi.com>
[not found] ` <485ACD92.8050109@sgi.com>
2008-06-19 21:35 ` Jeremy Fitzhardinge
2008-06-19 21:54 ` Jeremy Fitzhardinge
2008-06-19 22:13 ` Mike Travis
2008-06-19 22:21 ` Jeremy Fitzhardinge
2008-06-30 17:49 ` Mike Travis
2008-06-19 22:23 ` Jeremy Fitzhardinge
[not found] ` <485BDB04.4090709@sgi.com>
2008-06-20 17:25 ` Jeremy Fitzhardinge
2008-06-20 17:48 ` Christoph Lameter
2008-06-20 18:30 ` Mike Travis
2008-06-20 18:40 ` Jeremy Fitzhardinge
2008-06-20 18:37 ` Jeremy Fitzhardinge
2008-06-20 18:51 ` Christoph Lameter
2008-06-20 19:04 ` Jeremy Fitzhardinge
2008-06-20 19:21 ` H. Peter Anvin [this message]
2008-06-20 19:43 ` Eric W. Biederman
2008-06-20 20:04 ` Mike Travis
2008-06-20 20:37 ` Christoph Lameter
2008-06-20 19:06 ` Mike Travis
2008-06-20 20:25 ` Eric W. Biederman
2008-06-20 20:55 ` Christoph Lameter
2008-06-23 16:55 ` Mike Travis
2008-06-23 17:33 ` Jeremy Fitzhardinge
2008-06-23 18:04 ` Mike Travis
2008-06-23 18:36 ` Mike Travis
2008-06-23 19:41 ` Jeremy Fitzhardinge
2008-06-24 0:02 ` Mike Travis
2008-06-30 17:07 ` Mike Travis
2008-06-30 17:18 ` H. Peter Anvin
2008-06-30 17:57 ` Mike Travis
2008-06-30 20:50 ` Eric W. Biederman
2008-06-30 21:08 ` Jeremy Fitzhardinge
2008-07-01 8:40 ` Eric W. Biederman
2008-07-01 16:27 ` Jeremy Fitzhardinge
2008-07-01 16:55 ` Mike Travis
2008-07-01 16:56 ` H. Peter Anvin
2008-07-01 17:26 ` Jeremy Fitzhardinge
2008-07-01 20:40 ` Eric W. Biederman
2008-07-01 21:10 ` Jeremy Fitzhardinge
2008-07-01 21:39 ` Eric W. Biederman
2008-07-01 21:52 ` Jeremy Fitzhardinge
2008-07-02 0:20 ` H. Peter Anvin
2008-07-02 1:15 ` Mike Travis
2008-07-02 1:32 ` Eric W. Biederman
2008-07-02 1:51 ` Mike Travis
2008-07-02 2:50 ` Eric W. Biederman
2008-07-02 1:40 ` H. Peter Anvin
2008-07-02 1:44 ` Mike Travis
2008-07-02 1:45 ` H. Peter Anvin
2008-07-02 1:55 ` Mike Travis
2008-07-02 22:50 ` Mike Travis
2008-07-03 4:34 ` Eric W. Biederman
2008-07-07 17:17 ` Mike Travis
2008-07-07 19:46 ` Eric W. Biederman
2008-07-08 18:21 ` Mike Travis
2008-07-08 23:36 ` Eric W. Biederman
2008-07-08 23:49 ` Jeremy Fitzhardinge
2008-07-09 14:39 ` Mike Travis
2008-07-25 20:06 ` Mike Travis
2008-07-25 20:12 ` Jeremy Fitzhardinge
2008-07-25 20:34 ` Mike Travis
2008-07-25 20:43 ` Jeremy Fitzhardinge
2008-07-25 21:05 ` Mike Travis
2008-07-09 14:37 ` Mike Travis
2008-07-09 22:38 ` Eric W. Biederman
2008-07-09 23:30 ` Mike Travis
2008-07-10 0:04 ` Eric W. Biederman
2008-07-02 2:01 ` H. Peter Anvin
2008-07-02 3:08 ` Eric W. Biederman
2008-07-01 21:11 ` Andi Kleen
2008-07-01 21:42 ` Eric W. Biederman
2008-07-01 18:41 ` Eric W. Biederman
2008-07-01 12:09 ` Mike Travis
2008-07-01 11:49 ` Mike Travis
2008-06-30 17:43 ` Jeremy Fitzhardinge
2008-06-04 0:30 ` [PATCH 4/4] x86: Replace xxx_pda() operations with x86_xx_percpu() Mike Travis
2008-06-09 13:03 ` Ingo Molnar
2008-06-09 16:08 ` Mike Travis
2008-06-09 17:36 ` Mike Travis
2008-06-09 18:20 ` Christoph Lameter
2008-06-09 23:29 ` Jeremy Fitzhardinge
2008-06-10 10:09 ` Ingo Molnar
2008-06-10 15:07 ` Mike Travis
2008-06-04 10:18 ` [PATCH] x86: collapse the various size-dependent percpu accessors together Jeremy Fitzhardinge
2008-06-04 10:45 ` Jeremy Fitzhardinge
2008-06-04 11:29 ` Ingo Molnar
2008-06-04 12:09 ` Jeremy Fitzhardinge
2008-06-10 17:21 ` Christoph Lameter
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