From mboxrd@z Thu Jan 1 00:00:00 1970 From: arnd@arndb.de (Arnd Bergmann) Date: Wed, 28 Jul 2010 12:46:02 +0200 Subject: Questions about FPU and NEON on Cortex-A9 with armv7 instructions! In-Reply-To: References: <4C4FF8FF.304@xenomai.org> Message-ID: <201007281246.03033.arnd@arndb.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wednesday 28 July 2010, David Yang wrote: > If the other kernel code doesn't save and restore the FPU context,then > it's risky. > > Can I use FPU just in one C file ? Usually if you need something like this, you're doing something wrong. Code that does a lot of computation should go generally live in user space, not a kernel module, though there are a few exceptions. Take a look at how drivers/md/raid6sse2.c uses kernel_fpu_begin() to do this on x86. Arnd