Subject: Re: Data Abort Exceptions
To: None <Richard.Earnshaw@buzzard.freeserve.co.uk>
From: Ben Harris <email@example.com>
Date: 07/22/2002 22:57:07
On Mon, 22 Jul 2002, Richard Earnshaw wrote:
> > On ELF, will you have an exception handler that looks at the aborted
> > instrcution, basically interprets it? I believe that's how Linux does
> > it, although I didn't look closely. Or will you just kill the process
> > that does it?
> No, we will probably fault it, at least for now; since it could well be
> code written to the old behaviour that expected a rotation to happen.
> Besides, expecting the kernel to fix up poorly written code is not
> something that I'd like to endorse.
I'd be strongly opposed to silently fixing up unaligned accesses, since
that will just leave the bugs for me to find on ARMv2 processors, where
they'd be a lot more subtle.
Oh, and faulting processes won't be killed directly -- they'll be sent
SIGBUS, and will probably be able to install a handler to do the fixup
themselves if they _really_ want to.
Ben Harris <firstname.lastname@example.org>
Portmaster, NetBSD/acorn26 <URL:http://www.netbsd.org/Ports/acorn26/>