Questions about FPU and NEON on Cortex-A9 with armv7 instructions!

Gilles Chanteperdrix gilles.chanteperdrix at
Wed Jul 28 06:45:44 EDT 2010

David Yang wrote:
> My God...
> The job for the FPU is big enough.
> But I am not sure the kernel itself won't use the FPU .

Of that you are sure: on ARM, the kernel does not use the FPU.

 And I just
> want to use FPU in my driver other than the whole kernel.
> 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 ?

Apparently, I could not make myself clear. So, looking at the code will
probably help you understand better.
drivers/md/raid6mmx.c and arch/x86/lib/mmx_32.c use fpu in kernel-space.
You just have to do it the same way.


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