From: Thiemo Seufer <ths@networkno.de>
To: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] MIPS CP0 not usable in kernel mode?
Date: Fri, 24 Mar 2006 17:02:00 +0000 [thread overview]
Message-ID: <20060324170200.GB18630@networkno.de> (raw)
In-Reply-To: <4422FB89.6000705@mail.berlios.de>
On Thu, Mar 23, 2006 at 08:48:25PM +0100, Stefan Weil wrote:
> Hello,
>
> according to MIPS32 4KE User's Manual, coprocessor CP0 is
> always usable when the processor is running in kernel mode.
>
> So in kernel mode, exception "CP0 is not usable" should
> not happen.
>
> I think the boolean expression which checks for the
> exception condition has to be inverted - see my patch
> for translate.c.
This is correct (otherwise it wouldn't be possible to ever enable CP0).
The Linux kernel (plus qemu startup) happens to avoid this particular
case, which might explain it wasn't caught earlier.
Thiemo
next prev parent reply other threads:[~2006-03-24 17:01 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-23 19:48 [Qemu-devel] [PATCH] MIPS CP0 not usable in kernel mode? Stefan Weil
2006-03-24 17:02 ` Thiemo Seufer [this message]
2006-03-29 12:09 ` [Qemu-devel] [PATCH] Fix some minor warnings from qemu-doc.texi Stefan Weil
2006-08-21 16:36 ` [Qemu-devel] [PATCH] Small fix for qemu-doc.texi Stefan Weil
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