Date: Sat, 25 Jan 1997 04:37:02 +1100 From: Bruce Evans <bde@zeta.org.au> To: bde@FreeBSD.org, julian@whistle.com Cc: hackers@FreeBSD.org Subject: Re: Bruce! HHHEEELLLLPPPP! Message-ID: <199701241737.EAA24032@godzilla.zeta.org.au>
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>can you tell me what I should do to make the interrupt from sio1 >bust it's way in through ANYTHING so that I can put a breakpoint >on it and try get a stacktrace when the thing freezes by sending >a character in? BREAK_TO_DEBUGGER or just a breakpoint on siointr() should already allow sio activity to interrupt almost anything and give control to ddb. You can't do any better without an NMI. >is this the sort of thing you could trap with the "Bruce debugger?" It wouldn't help grab control. Once it gets control it can single step better, unless cpu interrupts are already masked (as they are in siointr()). ddb doesn't mask cpu interrupts itself, so it never gets full control unless interrupts are already masked. Change the debugger trap gates in machdep.c to interrupt gates and remove the `sti' from BPTTRAP() in exception.s to fix this. More is required to keep control while single stepping. Bruce
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