On Mon, Feb 22, 2016 at 02:42:54PM -0800, Andy Lutomirski wrote:
> > +static int should_save_registers_directly(void)
>
> I don't like the name of this function because:
>
> > +{
> > + /*
> > + * In signal handling path, the kernel already checks if
> > + * FPU instructions have been used before it calls
> > + * copy_fpstate_to_sigframe(). We check this here again
> > + * to detect any potential mis-use and saving invalid
> > + * register values directly to a signal frame.
> > + */
> > + WARN_ONCE(!current->thread.fpu.fpstate_active,
> > + "direct FPU save with no math use\n");
>
> ... Here "direct" seems to mean that we're asking whether to directly save ...
>
> > +
> > + /*
> > + * In the case that we are using a compacted kernel
> > + * xsave area, we can not copy the thread.fpu.state
> > + * directly to userspace and *must* save it from the
> > + * registers directly.
> > + */
>
> ... and here "directly" means *both* copying directly to userspace and
> saving using xsave directly.
>
> So can you rename it to something with an obvious meaning like
> "may_memcpy_fpu_regs" or similar?
This function determines whether the kernel should do
copy_fpregs_to_sigframe(). Perhaps we can re-name it to
may_copy_fpregs_to_sigframe()?
--Yu-cheng
