Re: [PATCH] x86/fpu: Remove the _GPL from the kernel_fpu_begin/end() export

From: Jiri Kosina
Date: Sun May 05 2019 - 15:09:54 EST

On Sun, 5 May 2019, Rik van Riel wrote:

> > Using fpu code in kernel space in a kernel module is a derived work of
> > the kernel itself? dont get me wrong, but this is absurd. i mean you
> > limit the use of cpu instructions. the use of cpu instructions should
> > be free of any licensing issue. i would even argument you are
> > violating the license of the cpu ower given to the kernel by executing
> > it, by restricting its use for no reason
> Using FPU code in kernel space in a kernel module does not require the
> use of kernel_fpu_begin/end().
> The kernel module could simply disable preemption, save the FPU
> registers, use the FPU, restore the FPU registers, and reenable
> preemption.

That means the module basically reimplemented kernel_fpu_begin/end() in
its whole (not getting the further optimizations implemented by the
kernel, sure). And therefore I sort of don't see the point of "hiding" it.


Jiri Kosina