Re: [PATCH v4 07/31] target/ppc: Introduce DISAS_{EXIT,CHAIN}{,_UPDATE}

[David Gibson <david@gibson.dropbear.id.au>]

[-- Attachment #1: Type: text/plain, Size: 4474 bytes --]

On Wed, May 12, 2021 at 03:54:17PM -0300, matheus.ferst@eldorado.org.br wrote:
> From: Richard Henderson <richard.henderson@linaro.org>
> 
> Rewrite ppc_tr_tb_stop to handle these new codes.
> 
> Convert ctx->exception into these new codes at the end of
> ppc_tr_translate_insn, prior to pushing the change back
> throughout translate.c.
> 
> 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 | 75 ++++++++++++++++++++++++++++++++++++------
>  1 file changed, 65 insertions(+), 10 deletions(-)
> 
> diff --git a/target/ppc/translate.c b/target/ppc/translate.c
> index 7b23f85c11..4bebb00bb2 100644
> --- a/target/ppc/translate.c
> +++ b/target/ppc/translate.c
> @@ -182,6 +182,11 @@ struct DisasContext {
>      uint64_t insns_flags2;
>  };
>  
> +#define DISAS_EXIT         DISAS_TARGET_0  /* exit to main loop, pc updated */
> +#define DISAS_EXIT_UPDATE  DISAS_TARGET_1  /* exit to main loop, pc stale */
> +#define DISAS_CHAIN        DISAS_TARGET_2  /* lookup next tb, pc updated */
> +#define DISAS_CHAIN_UPDATE DISAS_TARGET_3  /* lookup next tb, pc stale */
> +
>  /* Return true iff byteswap is needed in a scalar memop */
>  static inline bool need_byteswap(const DisasContext *ctx)
>  {
> @@ -9417,28 +9422,78 @@ static void ppc_tr_translate_insn(DisasContextBase *dcbase, CPUState *cs)
>                   opc3(ctx->opcode), opc4(ctx->opcode), ctx->opcode);
>      }
>  
> -    if (ctx->base.is_jmp == DISAS_NEXT
> -        && ctx->exception != POWERPC_EXCP_NONE) {
> -        ctx->base.is_jmp = DISAS_TOO_MANY;
> +    if (ctx->base.is_jmp == DISAS_NEXT) {
> +        switch (ctx->exception) {
> +        case POWERPC_EXCP_NONE:
> +            break;
> +        case POWERPC_EXCP_BRANCH:
> +            ctx->base.is_jmp = DISAS_NORETURN;
> +            break;
> +        case POWERPC_EXCP_SYNC:
> +        case POWERPC_EXCP_STOP:
> +            ctx->base.is_jmp = DISAS_EXIT;
> +            break;
> +        default:
> +            /* Every other ctx->exception should have set NORETURN. */
> +            g_assert_not_reached();
> +        }
>      }
>  }
>  
>  static void ppc_tr_tb_stop(DisasContextBase *dcbase, CPUState *cs)
>  {
>      DisasContext *ctx = container_of(dcbase, DisasContext, base);
> +    DisasJumpType is_jmp = ctx->base.is_jmp;
> +    target_ulong nip = ctx->base.pc_next;
>  
> -    if (ctx->base.is_jmp == DISAS_NORETURN) {
> +    if (is_jmp == DISAS_NORETURN) {
> +        /* We have already exited the TB. */
>          return;
>      }
>  
> -    if (ctx->exception == POWERPC_EXCP_NONE) {
> -        gen_goto_tb(ctx, 0, ctx->base.pc_next);
> -    } else if (ctx->exception != POWERPC_EXCP_BRANCH) {
> -        if (unlikely(ctx->base.singlestep_enabled)) {
> -            gen_debug_exception(ctx);
> +    /* Honor single stepping. */
> +    if (unlikely(ctx->base.singlestep_enabled)) {
> +        switch (is_jmp) {
> +        case DISAS_TOO_MANY:
> +        case DISAS_EXIT_UPDATE:
> +        case DISAS_CHAIN_UPDATE:
> +            gen_update_nip(ctx, nip);
> +            break;
> +        case DISAS_EXIT:
> +        case DISAS_CHAIN:
> +            break;
> +        default:
> +            g_assert_not_reached();
>          }
> -        /* Generate the return instruction */
> +        gen_debug_exception(ctx);
> +        return;
> +    }
> +
> +    switch (is_jmp) {
> +    case DISAS_TOO_MANY:
> +        if (use_goto_tb(ctx, nip)) {
> +            tcg_gen_goto_tb(0);
> +            gen_update_nip(ctx, nip);
> +            tcg_gen_exit_tb(ctx->base.tb, 0);
> +            break;
> +        }
> +        /* fall through */
> +    case DISAS_CHAIN_UPDATE:
> +        gen_update_nip(ctx, nip);
> +        /* fall through */
> +    case DISAS_CHAIN:
> +        tcg_gen_lookup_and_goto_ptr();
> +        break;
> +
> +    case DISAS_EXIT_UPDATE:
> +        gen_update_nip(ctx, nip);
> +        /* fall through */
> +    case DISAS_EXIT:
>          tcg_gen_exit_tb(NULL, 0);
> +        break;
> +
> +    default:
> +        g_assert_not_reached();
>      }
>  }
>  

-- 
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

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]