Re: Kernel oops with 2.6.26, padlock and ipsec: probably problem with fpu state changes

H. Peter Anvin
2008-08-12T00:55:37Z

Herbert Xu wrote:
> On Mon, Aug 11, 2008 at 05:42:21PM -0700, H. Peter Anvin wrote:
>> That's not sufficient, though, because you have to track all the state
>> and how it relates to everything. You now have to track both the
>> userspace FPU state and the potential kernel FPU state. The VIA
>> instructions are special (in the short bus to school sense) in that they
>> use a mechanism intended to protect specific state to protect -- exactly
>> nothing.
>
> Sorry, the kernel TS state is what I meant. I'm definitely not
> advocating the saving of the kernel FPU state. This is only for
> things like the VIA (which also exists for other processors, see
> the xor SSE stuff in include/asm-x86).

No, there you are actually using the FPU state (which includes the SSE
state.)

-hpa