From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@arm.linux.org.uk (Russell King - ARM Linux) Date: Fri, 20 Jan 2012 11:56:06 +0000 Subject: Building of arch/arm/plat-mxc/ssi-fiq.S failed w/ THUMB2 enabled? In-Reply-To: <20111202133911.GC2892@localhost.localdomain> References: <20111202102418.GT26618@pengutronix.de> <20111202133911.GC2892@localhost.localdomain> Message-ID: <20120120115606.GL1068@n2100.arm.linux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Dec 02, 2011 at 01:39:11PM +0000, Dave Martin wrote: > Is this code still used on ARMv7 and above? FIQ is not normally > available for Linux interrupts on hardware which makes use of the > TrustZone security extensions. Plus, on modern hardware with a deep > memory hierarchy, FIQ is may not be all that "fast" either, due to > cache/TLB effects. It's worth pointing out that people end up using FIQs for certain things because the hardware requires you to do it. So if a platform is using them, they're probably not doing it out of choice, but are doing it because it's a baseline requirement to get something working.