[Top] [All Lists]

Re: Kernel crash in / bcm1480 with 16k page size

To: Ralf Baechle <>
Subject: Re: Kernel crash in / bcm1480 with 16k page size
From: "Maciej W. Rozycki" <>
Date: Mon, 1 Feb 2010 14:50:27 +0000 (GMT)
Cc: Guenter Roeck <>, David Daney <>, "" <>
In-reply-to: <>
Original-recipient: rfc822;
References: <> <> <> <> <> <> <> <> <> <> <>
User-agent: Alpine 2.00 (LFD 1167 2008-08-23)
On Mon, 1 Feb 2010, Ralf Baechle 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.


<Prev in Thread] Current Thread [Next in Thread>