Hi Segher,
> On Thu, Jun 15, 2017 at 09:46:38AM +1000, Anton Blanchard wrote:
> > The mcrf emulation code was looking at the CR fields in the reverse
> > order. It also relied on reserved fields being zero which is
> > somewhat fragile, so fix that too.
>
> It masked out the reserved bits. I find the new code to be less
> readable (but also more correct ;-) ).
Thanks for that, not sure how I missed it :) I'll respin a simpler
patch.
> Maybe there should be (inline)
> helper function to insert/extract CR fields?
That would be nice, there are quite a few places that could use it.
Anton
> Segher
>
>
> > --- a/arch/powerpc/lib/sstep.c
> > +++ b/arch/powerpc/lib/sstep.c
> > @@ -683,8 +683,10 @@ int analyse_instr(struct instruction_op *op,
> > struct pt_regs *regs, case 19:
> > switch ((instr >> 1) & 0x3ff) {
> > case 0: /* mcrf */
> > - rd = (instr >> 21) & 0x1c;
> > - ra = (instr >> 16) & 0x1c;
> > + rd = 7 - ((instr >> 23) & 0x7);
> > + ra = 7 - ((instr >> 18) & 0x7);
> > + rd *= 4;
> > + ra *= 4;
> > val = (regs->ccr >> ra) & 0xf;
> > regs->ccr = (regs->ccr & ~(0xfUL << rd)) |
> > (val << rd); goto instr_done;
>
