On Wed, 2016-07-27 at 17:21 +1000, David Gibson wrote:
> On Wed, Jul 27, 2016 at 04:56:29PM +1000, Benjamin Herrenschmidt
> wrote:
> >
> > We don't implement imprecise FP exceptions and using store_current
> > which sets SRR1 to the *previous* instruction never makes sense
> > for these. So let's be truthful and make them precise, which is
> > allowed by the architecture.
> >
> > Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org>
> > ---
> > target-ppc/excp_helper.c | 11 ++++++-----
> > target-ppc/translate.c | 1 -
> > 2 files changed, 6 insertions(+), 6 deletions(-)
> >
> > diff --git a/target-ppc/excp_helper.c b/target-ppc/excp_helper.c
> > index 96c6fd9..02d9e79 100644
> > --- a/target-ppc/excp_helper.c
> > +++ b/target-ppc/excp_helper.c
> > @@ -274,12 +274,13 @@ static inline void powerpc_excp(PowerPCCPU
> > *cpu, int excp_model, int excp)
> > env->error_code = 0;
> > return;
> > }
> > +
> > + /* FP exceptions always have NIP pointing to the
> > faulting
> > + * instruction, so always use store_next and claim we
> > are
> > + * precise in the MSR.
> > + */
> > msr |= 0x00100000;
> > - if (msr_fe0 == msr_fe1) {
> > - goto store_next;
> > - }
> > - msr |= 0x00010000;
> > - break;
> > + goto store_next;
> > case POWERPC_EXCP_INVAL:
> > LOG_EXCP("Invalid instruction at " TARGET_FMT_lx "\n",
> > env->nip);
> > msr |= 0x00080000;
> > diff --git a/target-ppc/translate.c b/target-ppc/translate.c
> > index 3cfa40f..ba14bda 100644
> > --- a/target-ppc/translate.c
> > +++ b/target-ppc/translate.c
> > @@ -3060,7 +3060,6 @@ static void
> > gen_conditional_store(DisasContext *ctx, TCGv EA,
> > int reg, int size)
> > {
> > TCGv t0 = tcg_temp_new();
> > - uint32_t save_exception = ctx->exception;
>
> This looks like an unrelated change, and one which would break
> compile
> without other changes in gen_conditional_store() that I don't see.
>
> Have you compiled the user-only targets with this change?
Ah yes, the whole series does work in user-only, I tested, it's
just a messup beween 2 commits. The rest of the change is in:
"ppc: Rework NIP updates vs. exception generation"
What happened is that I initially forgot to remove that line
from the above commit, causing a warning. I did a fix, then
folded the fix into the wrong commmit :)
You can either take it out of this commit and put it into the
above mentioned one, or I can do a 3rd spin... but the fix is
trivial.
Cheers,
Ben.
> >
> > tcg_gen_st_tl(EA, cpu_env, offsetof(CPUPPCState, reserve_ea));
> > tcg_gen_movi_tl(t0, (size << 5) | reg);
>
