Re: Architectures where unaligned access is (not) OK?

[Guillem Jover <guillem@debian.org>]

On Fri, 2014-11-21 at 18:01:11 +0100, Jakub Wilk wrote:
> * Felipe Sateler <fsateler@debian.org>, 2014-11-21, 14:04:
> >Sparc is definitely not ok. For evidence, see #721617, liblo was trying to
> >fetch a double from a 4-byte aligned address. Experience with liblo shows
> >that other architectures are just fine (or at least are just slower) with
> >this type of unalignment.
> 
> IME, sprac buildds are the only ones where where unaligned access in a
> build-time test suite triggers SIGBUS/SIGSEGV.
> 
> Now that sparc is no long a release architecture, these kind of problems are
> likely to go unnoticed. :-(

Generating SIGBUS should be configurable at least on ia64, hppa, powerpc
and alpha. Most of those not available in Debian anymore. :(

See PR_SET_UNALIGN in prctl(2). At least ia64 used to have a prctl(8)
tool.

Thanks,
Guillem