From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Chris Friesen <cfriesen@nortel.com>
Cc: linuxppc-dev list <linuxppc-dev@ozlabs.org>
Subject: Re: question on inline assembly and long long values
Date: Thu, 07 Apr 2005 09:49:23 +1000 [thread overview]
Message-ID: <1112831363.9518.215.camel@gaston> (raw)
In-Reply-To: <42547112.9000302@nortel.com>
On Wed, 2005-04-06 at 17:30 -0600, Chris Friesen wrote:
> Benjamin Herrenschmidt wrote:
> > On Wed, 2005-04-06 at 12:26 -0600, Chris Friesen wrote:
> >
> >>I want to retrieve the msr (which is 64-bits) on a 970 when running in
> >>32-bit mode.
>
> > Is this in kernel mode ? Why are you doing that ?
>
> Yes it is.
>
> We wanted to manipulate the high word of the msr on the 970, from C
> code, while running in 32-bit mode. I'll be doing something similar to
> get at the high word of HID1 (to enable the en_icbi bit).
>
> Is there some other way to do this?
But the kernel code always runs in 64 bits mode... or are you trying to
pass that down to userland ? In the later case, your optimisations are
pretty much nothing compared to the cost of a syscall
Ben.
next prev parent reply other threads:[~2005-04-06 23:50 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-06 18:26 question on inline assembly and long long values Chris Friesen
2005-04-06 19:16 ` Kumar Gala
2005-04-06 20:01 ` Chris Friesen
2005-04-06 21:18 ` Gabriel Paubert
2005-04-06 21:37 ` Chris Friesen
2005-04-06 23:19 ` Benjamin Herrenschmidt
2005-04-06 23:30 ` Chris Friesen
2005-04-06 23:49 ` Benjamin Herrenschmidt [this message]
2005-04-06 23:56 ` Chris Friesen
2005-04-06 23:57 ` Benjamin Herrenschmidt
2005-04-07 0:09 ` Chris Friesen
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