On Mon, May 17, 2021 at 05:50:03PM -0300, matheus.ferst@eldorado.org.br wrote:
> From: Richard Henderson <richard.henderson@linaro.org>
> 
> 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>

Applied to ppc-for-6.1, thanks.

> ---
>  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 d51a1913a7..060ef83bc0 100644
> --- a/target/ppc/translate.c
> +++ b/target/ppc/translate.c
> @@ -304,6 +304,20 @@ 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.
> @@ -540,24 +554,14 @@ void spr_write_ureg(DisasContext *ctx, int sprn, int gprn)
>  #if !defined(CONFIG_USER_ONLY)
>  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);
> -    }
>  }
>  
>  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
>  
> @@ -565,24 +569,14 @@ void spr_write_decr(DisasContext *ctx, int sprn, int gprn)
>  /* Time base */
>  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);
> -    }
>  }
>  
>  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);
> -    }
>  }
>  
>  void spr_read_atbl(DisasContext *ctx, int gprn, int sprn)
> @@ -598,24 +592,14 @@ void spr_read_atbu(DisasContext *ctx, int gprn, int sprn)
>  #if !defined(CONFIG_USER_ONLY)
>  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);
> -    }
>  }
>  
>  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);
> -    }
>  }
>  
>  void spr_write_atbl(DisasContext *ctx, int sprn, int gprn)
> @@ -631,80 +615,45 @@ void spr_write_atbu(DisasContext *ctx, int sprn, int gprn)
>  #if defined(TARGET_PPC64)
>  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);
> -    }
>  }
>  
>  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 */
>  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);
> -    }
>  }
>  
>  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);
> -    }
>  }
>  
>  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);
> -    }
>  }
>  
>  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);
> -    }
>  }
>  
>  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
> @@ -912,71 +861,41 @@ void spr_write_601_ubatl(DisasContext *ctx, int sprn, int gprn)
>  #if !defined(CONFIG_USER_ONLY)
>  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);
> -    }
>  }
>  
>  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);
> -    }
>  }
>  
>  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);
> -    }
>  }
>  
>  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);
> -    }
>  }
>  
>  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);
> -    }
>  }
>  
>  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
>  
> @@ -2860,18 +2779,13 @@ 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
> @@ -5013,9 +4927,7 @@ 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;
> @@ -5030,9 +4942,7 @@ 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;
> @@ -5047,9 +4957,7 @@ 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;
> @@ -5379,9 +5287,7 @@ 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();
> @@ -5416,9 +5322,7 @@ 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();

-- 
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