| Message ID | 1469571686-7284-12-git-send-email-benh@kernel.crashing.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Jul 27, 2016 at 08:21:06AM +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. I don't see any store_correct in the altered code, so the description doesn't quite make sense to me. > > Signed-off-by: Benjamin Herrenschmidt <benh@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 f4b115e..91fdf4b 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 cb4e313..a05fed7 100644 > --- a/target-ppc/translate.c > +++ b/target-ppc/translate.c > @@ -2846,7 +2846,6 @@ static void gen_conditional_store(DisasContext *ctx, TCGv EA, > int reg, int size) > { > TCGv t0 = tcg_temp_new(); > - uint32_t save_exception = ctx->exception; Also, this appears to be an unrelated change. > tcg_gen_st_tl(EA, cpu_env, offsetof(CPUPPCState, reserve_ea)); > tcg_gen_movi_tl(t0, (size << 5) | reg);
On Wed, 2016-07-27 at 12:00 +1000, David Gibson wrote: > On Wed, Jul 27, 2016 at 08:21:06AM +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. > > I don't see any store_correct in the altered code, so the description > doesn't quite make sense to me. The existing program check default to store_current. We want store_next. The labels are misnamed, I fix that in a subsequent patch. store_current means use the "current" ctx->nip which is usually pointing to the *next* instruction ;-) (though not always). It's all very messy and fixing that is what a susequent patch in the series does. > > > > > > Signed-off-by: Benjamin Herrenschmidt <benh@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 f4b115e..91fdf4b 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 cb4e313..a05fed7 100644 > > --- a/target-ppc/translate.c > > +++ b/target-ppc/translate.c > > @@ -2846,7 +2846,6 @@ static void > > gen_conditional_store(DisasContext *ctx, TCGv EA, > > int reg, int size) > > { > > TCGv t0 = tcg_temp_new(); > > - uint32_t save_exception = ctx->exception; > > Also, this appears to be an unrelated change. > > > > > tcg_gen_st_tl(EA, cpu_env, offsetof(CPUPPCState, reserve_ea)); > > tcg_gen_movi_tl(t0, (size << 5) | reg); >
diff --git a/target-ppc/excp_helper.c b/target-ppc/excp_helper.c index f4b115e..91fdf4b 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 cb4e313..a05fed7 100644 --- a/target-ppc/translate.c +++ b/target-ppc/translate.c @@ -2846,7 +2846,6 @@ static void gen_conditional_store(DisasContext *ctx, TCGv EA, int reg, int size) { TCGv t0 = tcg_temp_new(); - uint32_t save_exception = ctx->exception; tcg_gen_st_tl(EA, cpu_env, offsetof(CPUPPCState, reserve_ea)); tcg_gen_movi_tl(t0, (size << 5) | reg);
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 <benh@kernel.crashing.org> --- target-ppc/excp_helper.c | 11 ++++++----- target-ppc/translate.c | 1 - 2 files changed, 6 insertions(+), 6 deletions(-)