From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@arm.linux.org.uk (Russell King - ARM Linux) Date: Fri, 5 Mar 2010 21:01:36 +0000 Subject: [PATCH] make the default alignment trap behavior configurable for user space In-Reply-To: <20100305150101.GC23225@pengutronix.de> References: <200812111015.28688.siarhei.siamashka@nokia.com> <20100305150101.GC23225@pengutronix.de> Message-ID: <20100305210136.GD4885@n2100.arm.linux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Mar 05, 2010 at 04:01:01PM +0100, Uwe Kleine-K?nig wrote: > I like that patch. (And I'd choose SIGBUS.) > > Is it still considered? Absolutely not. 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.