From: Ralf Baechle <ralf@linux-mips.org>
To: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: Guenter Roeck <guenter.roeck@ericsson.com>,
David Daney <ddaney@caviumnetworks.com>,
"linux-mips@linux-mips.org" <linux-mips@linux-mips.org>
Subject: Re: Kernel crash in 2.6.32.6 / bcm1480 with 16k page size
Date: Mon, 1 Feb 2010 16:26:01 +0100 [thread overview]
Message-ID: <20100201152601.GA22640@linux-mips.org> (raw)
In-Reply-To: <alpine.LFD.2.00.1002011448050.26199@eddie.linux-mips.org>
On Mon, Feb 01, 2010 at 02:50:27PM +0000, Maciej W. Rozycki wrote:
> > Write a value with all bits set to c0_entryhi, then read it back again.
> > The set bits in the VPN2 bitfield will indicate the size of the virtual
> > address range supported. The MIPS64 documentation also calls this value
> > SEGBITS. The nice thing about this probe is that it is supported for
> > all 64-bit MIPS processors except the R8000 which has an entirely different
> > TLB scheme anyway.
> >
> > Similarly it is possible to probe the physical address range in either
> > c0_entrylo0 or c0_entrylo1. This is also of interest on 32-bit processors.
>
> Indeed -- IIRC the architecture spec calls this value PABITS. I wasn't
> sure about the legacy processors -- if that works with them too, then it's
> even better.
The probing method was undocumented until MIPS64 but if you look at the
format of the EntryLo register it's always been possible. The R10000
needs special treatment though - it has the UC (Uncache Attribute) field
in the bits 62..63 of EntryLo; this field needs to be ignored.
Ralf
next prev parent reply other threads:[~2010-02-01 15:25 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-28 15:55 Kernel crash in 2.6.32.6 / bcm1480 with 16k page size Guenter Roeck
2010-01-29 13:24 ` Ralf Baechle
2010-01-29 15:12 ` Guenter Roeck
2010-01-29 17:11 ` David Daney
2010-01-29 18:06 ` Ralf Baechle
2010-01-29 18:21 ` Guenter Roeck
2010-01-30 2:05 ` Ralf Baechle
2010-01-30 21:34 ` Guenter Roeck
2010-01-31 3:19 ` Guenter Roeck
2010-01-29 18:39 ` Guenter Roeck
2010-01-29 18:56 ` David Daney
2010-01-29 19:25 ` Guenter Roeck
2010-01-29 19:28 ` David Daney
2010-01-29 19:58 ` Guenter Roeck
2010-01-31 9:10 ` Maciej W. Rozycki
2010-01-31 16:55 ` Guenter Roeck
2010-02-01 2:18 ` Ralf Baechle
2010-02-01 14:50 ` Maciej W. Rozycki
2010-02-01 15:26 ` Ralf Baechle [this message]
2010-02-01 23:11 ` Maciej W. Rozycki
2010-02-01 15:04 ` Guenter Roeck
2010-02-01 20:21 ` Guenter Roeck
2010-02-01 20:49 ` Ralf Baechle
2010-02-01 21:12 ` Guenter Roeck
2010-01-29 20:00 ` Guenter Roeck
2010-01-29 20:23 ` David Daney
2010-01-29 22:19 ` Guenter Roeck
2010-01-29 18:24 ` Guenter Roeck
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