On Wed, Jun 29, 2016 at 10:00:57PM +1000, Benjamin Herrenschmidt wrote: > On Fri, 2016-06-24 at 13:18 -0700, Aaron Larson wrote: > > Call gen_pause for all "or rx,rx,rx" encodings other nop. This > > provides a reasonable implementation for yield, and a better > > approximation for mdoio, mdoom, and miso. The choice to pause for > > all > > encodings !=0 leverages the PowerISA admonition that the reserved > > encodings might change program priority, providing a slight "future > > proofing". > > > > Signed-off-by: Aaron Larson <alar...@ddci.com> > > Acked-by: Benjamin Herrenschmidt <b...@kerne.crashing.org>
Applied to ppc-for-2.7, thanks.
> > ---
> > target-ppc/translate.c | 15 ++++++++-------
> > 1 file changed, 8 insertions(+), 7 deletions(-)
> >
> > diff --git a/target-ppc/translate.c b/target-ppc/translate.c
> > index 2f1c591..c4559b6 100644
> > --- a/target-ppc/translate.c
> > +++ b/target-ppc/translate.c
> > @@ -1471,7 +1471,7 @@ static void gen_or(DisasContext *ctx)
> > } else if (unlikely(Rc(ctx->opcode) != 0)) {
> > gen_set_Rc0(ctx, cpu_gpr[rs]);
> > #if defined(TARGET_PPC64)
> > - } else {
> > + } else if (rs != 0) { /* 0 is nop */
> > int prio = 0;
> >
> > switch (rs) {
> > @@ -1514,7 +1514,6 @@ static void gen_or(DisasContext *ctx)
> > break;
> > #endif
> > default:
> > - /* nop */
> > break;
> > }
> > if (prio) {
> > @@ -1524,13 +1523,15 @@ static void gen_or(DisasContext *ctx)
> > tcg_gen_ori_tl(t0, t0, ((uint64_t)prio) << 50);
> > gen_store_spr(SPR_PPR, t0);
> > tcg_temp_free(t0);
> > - /* Pause us out of TCG otherwise spin loops with smt_low
> > - * eat too much CPU and the kernel hangs
> > - */
> > + }
> > #if !defined(CONFIG_USER_ONLY)
> > - gen_pause(ctx);
> > + /* Pause out of TCG otherwise spin loops with smt_low eat
> > too much
> > + * CPU and the kernel hangs. This applies to all encodings
> > other
> > + * than no-op, e.g., miso(rs=26), yield(27), mdoio(29),
> > mdoom(30),
> > + * and all currently undefined.
> > + */
> > + gen_pause(ctx);
> > #endif
> > - }
> > #endif
> > }
> > }
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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