From: Eugene Surovegin <ebs@ebshome.net>
To: Stephen Williams <612dlag102@sneakemail.com>
Cc: linuxppc-embedded@lists.linuxppc.org
Subject: Re: [RFC] "indirect" DCR access (40x, BookE)
Date: Thu, 11 Mar 2004 20:54:51 -0800 [thread overview]
Message-ID: <20040312045451.GA25876@gate.ebshome.net> (raw)
In-Reply-To: <24019-11838@sneakemail.com>
On Thu, Mar 11, 2004 at 08:44:09PM -0800, Stephen Williams wrote:
> >>I think you should just write it as self modifying code :-)
> >>Write the instruction with the DCR number and just execute it.
> >
> >
> >And deal with locking and icache/dcache coherency ?
> >
> >No, thanks :)
>
>
> Actually, I recall that there is a code fixup mechanism that
> is invoked early in kernel init that does exactly that: it
> manages some machine specific differences by editing the code
> in place in a safe way.
Yes, you are correct, but this is done only once during startup and
nobody cares how fast it is. BTW, there is no locking issues at this
stage.
I'm not saying that it's impossible :). It's just not very efficient
to do such stuff on run-time (lock a spinlock, change memory, dcache
flush, icache invalidate, isync...)
Eugene.
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
next prev parent reply other threads:[~2004-03-12 4:54 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-12 1:48 [RFC] "indirect" DCR access (40x, BookE) Eugene Surovegin
2004-03-12 2:46 ` Dan Malek
2004-03-12 3:05 ` Eugene Surovegin
2004-03-12 4:44 ` Stephen Williams
2004-03-12 4:54 ` Eugene Surovegin [this message]
2004-03-12 14:25 ` Kumar Gala
2004-03-12 14:53 ` Chuck Meade
2004-03-12 16:20 ` Eugene Surovegin
2004-03-12 18:01 ` Dan Malek
2004-03-19 4:00 ` Benjamin Herrenschmidt
2004-03-23 2:47 ` Eugene Surovegin
2004-04-01 5:36 ` Kumar Gala
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