From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Wed, 24 Aug 2005 18:33:58 -1000
From: Tim Newsham <newsham@lava.net>
To: Fans of the OS Plan 9 from Bell Labs <9fans@cse.psu.edu>
Subject: Re: [9fans] rdbfs
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Message-ID: <Pine.BSI.4.61.0508241829220.26990@malasada.lava.net>
References: <5ee344bb91dbfd0f818b683a68a31583@coraid.com>
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> acid: lstk()
> <stdin>:2: (error) no stack frame

I used rdbfs often when working with sparc, but over tcp (minor
mods to rdbfs to not set baud, and then a small shim to invoke
it on an fd from dial()) since the computer was connected to
the serial port of a non-plan9 computer.

As for the stack frame -- I found it useful to modify the
acid startup files (/sys/lib/acid/*) to allow you to pick
which set of registers to use.  This lets you set the registers
to some ureg location such as the ureg's at the time of
an exception/trap so that you can trace back from that point.
The changes are fairly straightforward -- read registers from
offsets starting at the specified address rather than from
offset zero.  The big change is altering all accesses to registers
to go through the ureg pointer (which would default to zero for
real registers).

You can also try to manually interpret the stack frame, but its
a bit tedious without frame pointers.

Tim Newsham
http://www.lava.net/~newsham/