Subject: Re: [PATCH] powerpc/85xx: enable the math emulation for the corenet64_smp_defconfig

From: Scott Wood <[email-masked]>
Date: Wed, 10 Jul 2013 16:40:03 -0500

On 07/09/2013 08:49:52 PM, Kevin Hao wrote:
> I got the following error on my t4240qds board.
>   ntpd[2713]: unhandled signal 4 at 0fd5b448 nip 0fd5b448 lr 0fd5b424 =20
> code 30001
>=20
> The root cause is that the float point instruction 'fsqrt' is used.
> But this instruction is not implemented on e6500 core. Even this
> does seem a gcc bug, I would like to enable the math emulation
> in the kernel to workaround this kind of issue.

I'll apply this, but we should add PPC_WARN_EMULATED to math-emu so =20
that people know when their toolchain is emitting things that require =20
emulation.

It'd also be nice if we had an option to only include the portions of =20
math-emu that are known to be missing in some CPUs (excluding CPUs that =20
are missing the entire FPU, of course).  Besides its effect on kernel =20
image size, in my experience math-emu adds a non-trivial amount of time =20
to a kernel build.

-Scott=