[PATCH] make the default alignment trap behavior configurable for user space
Russell King - ARM Linux
linux at arm.linux.org.uk
Fri Mar 5 16:01:36 EST 2010
On Fri, Mar 05, 2010 at 04:01:01PM +0100, Uwe Kleine-König wrote:
> I like that patch. (And I'd choose SIGBUS.)
> Is it still considered?
Alignment faults _remain_ a reality. I've recently built a new glibc -
and guess what, it _relies_ upon alignment faults - I'm up to 2321607
userspace alignment faults.
If you decide to make alignment faults create a SIGBUS, then you kill any
system booting using some glibc's and with gconv support.
The hard fact is: the correct setting of the alignment fault handler is
_entirely_ _specific_ to the userspace you are running. There is no one
correct setting for it.
To this end, recent kernels now have a kernel command line option to
chose the correct alignment fault handling behaviour - which is the right
thing to do since a multi-platform kernel may require different options
for their different userspaces.
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