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From: "David S. Miller" <davem@davemloft.net>
To: sparclinux@vger.kernel.org
Subject: Re: RED State Exception on Ultra 1, 2.6.9-rc2
Date: Tue, 21 Sep 2004 06:31:24 +0000	[thread overview]
Message-ID: <20040920233124.1d7e79b2.davem@davemloft.net> (raw)
In-Reply-To: <1095742791.3421.3.camel@ori.thedillows.org>

On 21 Sep 2004 00:59:51 -0400
David Dillow <dave@thedillows.org> wrote:

> What's a RED State exception?

The CPU has storage internally for up to 5 levels of
trap information, this is called the trap stack.  When
you take a trap at the 4th level, the cpu enters RED
state and traps to a special vector in a trap table
at a fixed pre-determined address, with TLBs and caches
disabled, to process the trap.

When that happens, what usually occurs on Sun systems
is that the cpu jumps into Sun firmware code which dumps
out the trap stack like you see here.

> TL\000.0000.0000.0005 TT\000.0000.0000.0080
>    TPC\000.0000.0040.ec98 TnPC\000.0000.0040.ec9c TSTATE\000.0000.8000.9504
> TL\000.0000.0000.0004 TT\000.0000.0000.0010
>    TPC\000.0000.0040.d000 TnPC\000.0000.0040.d004 TSTATE\000.0000.8000.9504
> TL\000.0000.0000.0003 TT\000.0000.0000.0080
>    TPC\000.0000.0040.ec98 TnPC\000.0000.0040.ec9c TSTATE\000.0000.8000.9502
> TL\000.0000.0000.0002 TT\000.0000.0000.0010
>    TPC\000.0000.0040.8c00 TnPC\000.0000.0040.8c04 TSTATE\000.0000.8008.9402
> TL\000.0000.0000.0001 TT\000.0000.0000.0060
>    TPC\000.0000.0042.1b68 TnPC\000.0000.0042.1b6c TSTATE\000.0000.8000.9602

Can you match up these "TPC" and "TnPC" values to symbols in
the kernel running at the time of this crash?

  reply	other threads:[~2004-09-21  6:31 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-09-21  4:59 RED State Exception on Ultra 1, 2.6.9-rc2 David Dillow
2004-09-21  6:31 ` David S. Miller [this message]
2004-09-21 13:47 ` David Dillow
2004-09-21 14:50 ` Tim Walberg
2004-09-21 19:48 ` David S. Miller
2004-09-22  3:25 ` David Dillow
2004-09-22  3:35 ` David S. Miller
2004-10-08 16:51 ` David Dillow
2004-10-11  4:09 ` David S. Miller
2004-10-29  6:14 ` David Dillow

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