On Fri, Jun 17, 2011 at 03:23:49PM -0700, Steve Langasek wrote: > On Fri, Jun 17, 2011 at 01:10:11PM +0100, Dave Martin wrote: > > > For ARM, we can achieve the goal by augmenting the default kernel command- > > line options: either > > > alignment=3 > > Fix up each alingment fault, but also log the faulting address > > and name of the offending process to dmesg. > > > alignment=5 > > Pass each alignment fault to the user process as SIGBUS (fatal > > by default) and log the faulting address and name of the > > offending process to dmesg. > > > Fault statistics cat also be obtained at runtime by reading > > /proc/cpu/alignment. > > > For other architectures, there may be other arch-specific ways of > > achieving something similar. > > Other architectures[1] use the 'prctl' tool, which uses the > prctl(PR_SET_UNALIGN,...) kernel interface to control the unaligned trap > behavior for the process. If this can be sanely togglable on ARM at > runtime, it would be keen to use the same interface on this arch.
I guess that would be a new task for someone, if we consider it important enough -- I'll raise it at today's linaro kernel working group meeting. I don't know if that prctl call is wired up at all on arm kernels, but it certainly won't work for v6/v7 at present. Enabling it looks fairly straightforward, though. Cheers ---Dave -- To UNSUBSCRIBE, email to debian-arm-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/20110620103336.gd2...@arm.com
