Re: [PATCH v4 10/31] target/ppc: Introduce gen_icount_io_start

[David Gibson]

On Wed, May 12, 2021 at 04:21:13PM -0300, Matheus K. Ferst wrote:
> On 12/05/2021 15:54, matheus.ferst@eldorado.org.br wrote:
> > From: Matheus Ferst <matheus.ferst@eldorado.org.br>
> > 
> > Create a function to handle the details for interacting with icount.
> > 
> > Force the exit from the tb via DISAS_TOO_MANY, which allows chaining
> > to the next tb, where the code emitted for gen_tb_start() will
> > determine if we must exit.  We can thus remove any matching
> > conditional call to gen_stop_exception.
> > 
> > Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> > Signed-off-by: Matheus Ferst <matheus.ferst@eldorado.org.br>
> > ---
> >   target/ppc/translate.c | 174 +++++++++--------------------------------
> >   1 file changed, 39 insertions(+), 135 deletions(-)
> > 
> > diff --git a/target/ppc/translate.c b/target/ppc/translate.c
> > index 1c02e21a56..f6410dc76c 100644
> > --- a/target/ppc/translate.c
> > +++ b/target/ppc/translate.c
> > @@ -301,6 +301,20 @@ static void gen_exception_nip(DisasContext *ctx, 
> > uint32_t excp,
> >       ctx->base.is_jmp = DISAS_NORETURN;
> >   }
> > +static void gen_icount_io_start(DisasContext *ctx)
> > +{
> > +    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > +        gen_io_start();
> > +        /*
> > +         * An I/O instruction must be last in the TB.
> > +         * Chain to the next TB, and let the code from gen_tb_start
> > +         * decide if we need to return to the main loop.
> > +         * Doing this first also allows this value to be overridden.
> > +         */
> > +        ctx->base.is_jmp = DISAS_TOO_MANY;
> > +    }
> > +}
> > +
> >   /*
> >    * Tells the caller what is the appropriate exception to generate and 
> > prepares
> >    * SPR registers for this exception.
> > @@ -538,24 +552,14 @@ static void spr_write_ureg(DisasContext *ctx, int 
> > sprn, int gprn)
> >   #if !defined(CONFIG_USER_ONLY)
> >   static void spr_read_decr(DisasContext *ctx, int gprn, int sprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_load_decr(cpu_gpr[gprn], cpu_env);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   static void spr_write_decr(DisasContext *ctx, int sprn, int gprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_store_decr(cpu_env, cpu_gpr[gprn]);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   #endif
> > @@ -563,24 +567,14 @@ static void spr_write_decr(DisasContext *ctx, int 
> > sprn, int gprn)
> >   /* Time base */
> >   static void spr_read_tbl(DisasContext *ctx, int gprn, int sprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_load_tbl(cpu_gpr[gprn], cpu_env);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   static void spr_read_tbu(DisasContext *ctx, int gprn, int sprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_load_tbu(cpu_gpr[gprn], cpu_env);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   ATTRIBUTE_UNUSED
> > @@ -598,24 +592,14 @@ static void spr_read_atbu(DisasContext *ctx, int 
> > gprn, int sprn)
> >   #if !defined(CONFIG_USER_ONLY)
> >   static void spr_write_tbl(DisasContext *ctx, int sprn, int gprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_store_tbl(cpu_env, cpu_gpr[gprn]);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   static void spr_write_tbu(DisasContext *ctx, int sprn, int gprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_store_tbu(cpu_env, cpu_gpr[gprn]);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   ATTRIBUTE_UNUSED
> > @@ -634,80 +618,45 @@ static void spr_write_atbu(DisasContext *ctx, int 
> > sprn, int gprn)
> >   ATTRIBUTE_UNUSED
> >   static void spr_read_purr(DisasContext *ctx, int gprn, int sprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_load_purr(cpu_gpr[gprn], cpu_env);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   static void spr_write_purr(DisasContext *ctx, int sprn, int gprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_store_purr(cpu_env, cpu_gpr[gprn]);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   /* HDECR */
> >   static void spr_read_hdecr(DisasContext *ctx, int gprn, int sprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_load_hdecr(cpu_gpr[gprn], cpu_env);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   static void spr_write_hdecr(DisasContext *ctx, int sprn, int gprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_store_hdecr(cpu_env, cpu_gpr[gprn]);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   static void spr_read_vtb(DisasContext *ctx, int gprn, int sprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_load_vtb(cpu_gpr[gprn], cpu_env);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   static void spr_write_vtb(DisasContext *ctx, int sprn, int gprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_store_vtb(cpu_env, cpu_gpr[gprn]);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   static void spr_write_tbu40(DisasContext *ctx, int sprn, int gprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_store_tbu40(cpu_env, cpu_gpr[gprn]);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   #endif
> > @@ -915,71 +864,41 @@ static void spr_write_601_ubatl(DisasContext *ctx, 
> > int sprn, int gprn)
> >   #if !defined(CONFIG_USER_ONLY)
> >   static void spr_read_40x_pit(DisasContext *ctx, int gprn, int sprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_load_40x_pit(cpu_gpr[gprn], cpu_env);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   static void spr_write_40x_pit(DisasContext *ctx, int sprn, int gprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_store_40x_pit(cpu_env, cpu_gpr[gprn]);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   static void spr_write_40x_dbcr0(DisasContext *ctx, int sprn, int gprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_store_spr(sprn, cpu_gpr[gprn]);
> >       gen_helper_store_40x_dbcr0(cpu_env, cpu_gpr[gprn]);
> >       /* We must stop translation as we may have rebooted */
> >       gen_stop_exception(ctx);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   static void spr_write_40x_sler(DisasContext *ctx, int sprn, int gprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_store_40x_sler(cpu_env, cpu_gpr[gprn]);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   static void spr_write_booke_tcr(DisasContext *ctx, int sprn, int gprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_store_booke_tcr(cpu_env, cpu_gpr[gprn]);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   static void spr_write_booke_tsr(DisasContext *ctx, int sprn, int gprn)
> >   {
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_helper_store_booke_tsr(cpu_env, cpu_gpr[gprn]);
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_stop_exception(ctx);
> > -    }
> >   }
> >   #endif
> > @@ -2863,18 +2782,13 @@ static void gen_darn(DisasContext *ctx)
> >       if (l > 2) {
> >           tcg_gen_movi_i64(cpu_gpr[rD(ctx->opcode)], -1);
> >       } else {
> > -        if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -            gen_io_start();
> > -        }
> > +        gen_icount_io_start(ctx);
> >           if (l == 0) {
> >               gen_helper_darn32(cpu_gpr[rD(ctx->opcode)]);
> >           } else {
> >               /* Return 64-bit random for both CRN and RRN */
> >               gen_helper_darn64(cpu_gpr[rD(ctx->opcode)]);
> >           }
> > -        if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -            gen_stop_exception(ctx);
> > -        }
> >       }
> >   }
> >   #endif
> > @@ -5016,9 +4930,7 @@ static void gen_rfi(DisasContext *ctx)
> >       }
> >       /* Restore CPU state */
> >       CHK_SV;
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_update_cfar(ctx, ctx->cia);
> >       gen_helper_rfi(cpu_env);
> >       ctx->base.is_jmp = DISAS_EXIT;
> > @@ -5033,9 +4945,7 @@ static void gen_rfid(DisasContext *ctx)
> >   #else
> >       /* Restore CPU state */
> >       CHK_SV;
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_update_cfar(ctx, ctx->cia);
> >       gen_helper_rfid(cpu_env);
> >       ctx->base.is_jmp = DISAS_EXIT;
> > @@ -5050,9 +4960,7 @@ static void gen_rfscv(DisasContext *ctx)
> >   #else
> >       /* Restore CPU state */
> >       CHK_SV;
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       gen_update_cfar(ctx, ctx->cia);
> >       gen_helper_rfscv(cpu_env);
> >       ctx->base.is_jmp = DISAS_EXIT;
> > @@ -5382,9 +5290,7 @@ static void gen_mtmsrd(DisasContext *ctx)
> >       CHK_SV;
> >   #if !defined(CONFIG_USER_ONLY)
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       if (ctx->opcode & 0x00010000) {
> >           /* L=1 form only updates EE and RI */
> >           TCGv t0 = tcg_temp_new();
> > @@ -5419,9 +5325,7 @@ static void gen_mtmsr(DisasContext *ctx)
> >       CHK_SV;
> >   #if !defined(CONFIG_USER_ONLY)
> > -    if (tb_cflags(ctx->base.tb) & CF_USE_ICOUNT) {
> > -        gen_io_start();
> > -    }
> > +    gen_icount_io_start(ctx);
> >       if (ctx->opcode & 0x00010000) {
> >           /* L=1 form only updates EE and RI */
> >           TCGv t0 = tcg_temp_new();
> > 
> 
> Sorry, I somehow changed the author by mistake, which must be
> From: Richard Henderson <richard.henderson@linaro.org>

It turns out this no longer applies cleanly for me on ppc-for-6.1
anyway.  Please fix the attribution when you rebase for the next spin.

-- 
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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