Message ID | 1440375847-17603-20-git-send-email-cota@braap.org |
---|---|
State | New |
Headers | show |
Emilio G. Cota <cota@braap.org> writes: > Signed-off-by: Emilio G. Cota <cota@braap.org> > --- > tcg/tcg-op.h | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/tcg/tcg-op.h b/tcg/tcg-op.h > index 52482c0..3ec9f13 100644 > --- a/tcg/tcg-op.h > +++ b/tcg/tcg-op.h > @@ -716,6 +716,16 @@ static inline void tcg_gen_fence_full(void) > tcg_gen_op0(&tcg_ctx, INDEX_op_fence_full); > } > > +#if defined(__i386__) || defined(__x86_64__) || defined(__s390x__) > +static inline void tcg_gen_smp_rmb(void) > +{ } > +#else > +static inline void tcg_gen_smp_rmb(void) > +{ > + tcg_gen_fence_load(); > +} > +#endif This seems a little pointless wrapping up tcg_gen_fence_load. Could the magic dealing with the backend not be done with something like TCG_TARGET_HAS_fence_load. On the x86/x86_64 backends this could then NOP away. > + > /* QEMU specific operations. */ > > #ifndef TARGET_LONG_BITS
On Thu, Sep 10, 2015 at 17:01:14 +0100, Alex Bennée wrote: > > Emilio G. Cota <cota@braap.org> writes: > > > Signed-off-by: Emilio G. Cota <cota@braap.org> > > --- > > tcg/tcg-op.h | 10 ++++++++++ > > 1 file changed, 10 insertions(+) > > > > diff --git a/tcg/tcg-op.h b/tcg/tcg-op.h > > index 52482c0..3ec9f13 100644 > > --- a/tcg/tcg-op.h > > +++ b/tcg/tcg-op.h > > @@ -716,6 +716,16 @@ static inline void tcg_gen_fence_full(void) > > tcg_gen_op0(&tcg_ctx, INDEX_op_fence_full); > > } > > > > +#if defined(__i386__) || defined(__x86_64__) || defined(__s390x__) > > +static inline void tcg_gen_smp_rmb(void) > > +{ } > > +#else > > +static inline void tcg_gen_smp_rmb(void) > > +{ > > + tcg_gen_fence_load(); > > +} > > +#endif > > This seems a little pointless wrapping up tcg_gen_fence_load. Could the > magic dealing with the backend not be done with something like > TCG_TARGET_HAS_fence_load. On the x86/x86_64 backends this could then > NOP away. This patch made sense at the time as a companion to this other patch: cpu: add barriers around cpu->tcg_exit_req (snip) +++ b/include/exec/gen-icount.h @@ -16,6 +16,7 @@ static inline void gen_tb_start(TranslationBlock *tb) exitreq_label = gen_new_label(); flag = tcg_temp_new_i32(); + tcg_gen_smp_rmb(); tcg_gen_ld_i32(flag, cpu_env, offsetof(CPUState, tcg_exit_req) - ENV_OFFSET); tcg_gen_brcondi_i32(TCG_COND_NE, flag, 0, exitreq_label); Paolo had the better idea of calling smp_rmb() once we've exited TCG, which renders tcg_gen_smp_rmb() unnecessary. Emilio
diff --git a/tcg/tcg-op.h b/tcg/tcg-op.h index 52482c0..3ec9f13 100644 --- a/tcg/tcg-op.h +++ b/tcg/tcg-op.h @@ -716,6 +716,16 @@ static inline void tcg_gen_fence_full(void) tcg_gen_op0(&tcg_ctx, INDEX_op_fence_full); } +#if defined(__i386__) || defined(__x86_64__) || defined(__s390x__) +static inline void tcg_gen_smp_rmb(void) +{ } +#else +static inline void tcg_gen_smp_rmb(void) +{ + tcg_gen_fence_load(); +} +#endif + /* QEMU specific operations. */ #ifndef TARGET_LONG_BITS
Signed-off-by: Emilio G. Cota <cota@braap.org> --- tcg/tcg-op.h | 10 ++++++++++ 1 file changed, 10 insertions(+)