Subject: Re: Squid on Alpha blows up..
To: Andrew Brown <email@example.com>
From: Jason Thorpe <firstname.lastname@example.org>
Date: 03/03/1999 11:03:37
On Wed, 3 Mar 1999 11:41:15 -0500
Andrew Brown <email@example.com> wrote:
> >For this reason, we trap the unaligned access fault, and do one of 4
> >things, depending on sysctl variables:
> > (1) Silently fixup the unaligned access.
> > (2) Print out a message and fixup the unaligned access.
> > (3) Silently send the process a SIGBUS.
> > (4) Print out a message and send the process a SIGBUS.
> hmm. sigbus or not and message or not. so processes on alphas don't
> get sigbus'ed at all (modulo the sysctl setting)? would it
> "theoretically" be possible to do the same thing for other
> architectures? i'm just curious...
Well, a NetBSD/alpha process will get SIGBUS'd if it does other SIGBUS'able
access :-) i.e. accessing a nonexistent (vs. unmapped) memory location.
> >Also note that the NetBSD kernel will panic if unaligned access is
> >performed by the kernel, rather than by a user process.
> certainly. to where would it trap?
Same unaligned access fault handler, but if the processor is in kernel
mode when the fault occurs, the fault handler decides to panic, instead.
-- Jason R. Thorpe <firstname.lastname@example.org>