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From: "Dale Farnsworth" <dale@farnsworth•org>
To: Tom Rini <trini@kernel•crashing.org>, linuxppc-dev@lists•linuxppc.org
Subject: Re: Patch boot/common/relocate.S to start kernel at 0x000c
Date: Tue, 4 Mar 2003 17:07:08 -0700	[thread overview]
Message-ID: <20030305000708.GD4683@rover.farnsworth.org> (raw)
In-Reply-To: <20030304234253.GB17093@ip68-0-152-218.tc.ph.cox.net>


On Tue, Mar 04, 2003 at 11:42:53PM +0000, Tom Rini wrote:
> Thinking waaaay back, it was probably me doing something wrong. :)

That was my first thought, since prep/head.S starts the kernel at 0xc. :)

> The easy way to verify what really happens is to check out the MP code in
> prep/misc.c.  I would have thought that chrp smp would do the pmac thing
> of calling back to the fw, but I could be wrong here..

prep/misc.c just starts the secondary cpu at 0xc0, __secondary_hold.
It's ok for that to happen before cpu 0 runs the kernel, since
prep/head.S runs it at 0xc.

Pmacs also start the secondary at __secondary_hold, but after cpu 0 is
already running the kernel, so it's not an issue.

It looks to me like all ppc smp systems start their secondary cpus
at __secondary_hold.  (I'd like to know if I'm wrong about that.)
Since __secondary_hold writes to 0x4 and only reads 0x0 looking for
it's cpu id, I still like the "b __start" at 0x0.

Thanks,
-Dale

** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/

  reply	other threads:[~2003-03-05  0:07 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-03-04 19:16 Patch boot/common/relocate.S to start kernel at 0x000c Dale Farnsworth
2003-03-04 19:24 ` Dan Malek
2003-03-04 20:13   ` Dale Farnsworth
2003-03-04 20:21     ` Dan Malek
2003-03-04 23:08       ` Dale Farnsworth
2003-03-04 23:21         ` Dan Malek
2003-03-04 23:35           ` Dale Farnsworth
2003-03-04 23:42           ` Tom Rini
2003-03-05  0:07             ` Dale Farnsworth [this message]
2003-03-05  0:47               ` Paul Mackerras
2003-03-05  1:01                 ` Wolfgang Denk
2003-03-05  1:03                 ` Wolfgang Denk
     [not found]                   ` <15973.24544.124365.553602@argo.ozlabs.ibm.com>
2003-03-05  4:28                     ` Dale Farnsworth
2003-03-05  9:54                       ` Benjamin Herrenschmidt
2003-03-05 17:10                     ` Tom Rini
2003-03-11 18:45                     ` Dale Farnsworth
     [not found]                   ` <20030305022134.GR24171@kalmia.hozed.org>
2003-03-05  4:40                     ` Dale Farnsworth
2003-03-05 17:07                     ` Tom Rini
2003-03-05 17:24                   ` Dan Malek
2003-03-13 22:38       ` Dale Farnsworth
2003-03-14 11:43         ` Gabriel Paubert
2003-03-14 17:52           ` Dale Farnsworth

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