On Mon, 2017-07-31 at 10:58 +1000, Matt Brown wrote:
> This adds emulation for the prtyw and prtyd instructions.
> Tested for logical correctness against the prtyw and prtyd instructions
> on ppc64le.
>
> Signed-off-by: Matt Brown <matthew.brown....@gmail.com>
Reviewed-by: Cyril Bur <cyril...@gmail.com>
> ---
> v4:
> - use simpler xor method
> v3:
> - optimised using the Giles-Miller method of side-ways addition
> v2:
> - fixed opcodes
> - fixed bitshifting and typecast errors
> - merged do_prtyw and do_prtyd into single function
> ---
> arch/powerpc/lib/sstep.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
> index c9fd613..af4eef9 100644
> --- a/arch/powerpc/lib/sstep.c
> +++ b/arch/powerpc/lib/sstep.c
> @@ -657,6 +657,24 @@ static nokprobe_inline void do_bpermd(struct pt_regs
> *regs, unsigned long v1,
> regs->gpr[ra] = perm;
> }
> #endif /* CONFIG_PPC64 */
> +/*
> + * The size parameter adjusts the equivalent prty instruction.
> + * prtyw = 32, prtyd = 64
> + */
> +static nokprobe_inline void do_prty(struct pt_regs *regs, unsigned long v,
> + int size, int ra)
> +{
> + unsigned long long res = v ^ (v >> 8);
> +
> + res ^= res >> 16;
> + if (size == 32) { /* prtyw */
> + regs->gpr[ra] = res & 0x0000000100000001;
> + return;
> + }
> +
> + res ^= res >> 32;
> + regs->gpr[ra] = res & 1; /*prtyd */
> +}
>
> static nokprobe_inline int trap_compare(long v1, long v2)
> {
> @@ -1247,6 +1265,14 @@ int analyse_instr(struct instruction_op *op, struct
> pt_regs *regs,
> case 124: /* nor */
> regs->gpr[ra] = ~(regs->gpr[rd] | regs->gpr[rb]);
> goto logical_done;
> +
> + case 154: /* prtyw */
> + do_prty(regs, regs->gpr[rd], 32, ra);
> + goto logical_done;
> +
> + case 186: /* prtyd */
> + do_prty(regs, regs->gpr[rd], 64, ra);
> + goto logical_done;
> #ifdef CONFIG_PPC64
> case 252: /* bpermd */
> do_bpermd(regs, regs->gpr[rd], regs->gpr[rb], ra);
