Re: [Qemu-devel] [RFC v3 PATCH 07/14] tcg/ppc: Add support for fence

[Sergey Fedorov <serge.fdrv@gmail.com>]

On 18/06/16 07:03, Pranith Kumar wrote:
> Signed-off-by: Richard Henderson <rth@twiddle.net>
> Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
> ---
>  tcg/ppc/tcg-target.inc.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
>
> diff --git a/tcg/ppc/tcg-target.inc.c b/tcg/ppc/tcg-target.inc.c
> index da10052..766848e 100644
> --- a/tcg/ppc/tcg-target.inc.c
> +++ b/tcg/ppc/tcg-target.inc.c
> @@ -469,6 +469,10 @@ static int tcg_target_const_match(tcg_target_long val, TCGType type,
>  #define STHX   XO31(407)
>  #define STWX   XO31(151)
>  
> +#define EIEIO  XO31(854)
> +#define HWSYNC XO31(598)
> +#define LWSYNC (HWSYNC | (1u << 21))
> +
>  #define SPR(a, b) ((((a)<<5)|(b))<<11)
>  #define LR     SPR(8, 0)
>  #define CTR    SPR(9, 0)
> @@ -1237,6 +1241,21 @@ static void tcg_out_brcond2 (TCGContext *s, const TCGArg *args,
>      tcg_out_bc(s, BC | BI(7, CR_EQ) | BO_COND_TRUE, arg_label(args[5]));
>  }
>  
> +static void tcg_out_mb(TCGContext *s, TCGArg a0)
> +{
> +    switch (a0 & TCG_MO_ALL) {
> +    case TCG_MO_LD_LD:
> +        tcg_out32(s, LWSYNC);

lwsync can be used for all cases except store-load which requires
hwsync. eieio is for synchronizing memory-mapped IO which is not used by
TCG at all. So there should be:

    switch (a0 & TCG_MO_ALL) {
    case TCG_MO_ST_LD:
        tcg_out32(s, HWSYNC);
        break;
    default:
        tcg_out32(s, LWSYNC);
        break;
    }

Kind regards,
Sergey

> +        break;
> +    case TCG_MO_ST_ST:
> +        tcg_out32(s, EIEIO);
> +        break;
> +    default:
> +        tcg_out32(s, HWSYNC);
> +        break;
> +    }
> +}
> +
>  #ifdef __powerpc64__
>  void ppc_tb_set_jmp_target(uintptr_t jmp_addr, uintptr_t addr)
>  {
> @@ -2439,6 +2458,10 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc, const TCGArg *args,
>          tcg_out32(s, MULHD | TAB(args[0], args[1], args[2]));
>          break;
>  
> +    case INDEX_op_mb:
> +        tcg_out_mb(s, args[0]);
> +        break;
> +
>      case INDEX_op_mov_i32:   /* Always emitted via tcg_out_mov.  */
>      case INDEX_op_mov_i64:
>      case INDEX_op_movi_i32:  /* Always emitted via tcg_out_movi.  */
> @@ -2586,6 +2609,7 @@ static const TCGTargetOpDef ppc_op_defs[] = {
>      { INDEX_op_qemu_st_i64, { "S", "S", "S", "S" } },
>  #endif
>  
> +    { INDEX_op_mb, { } },
>      { -1 },
>  };
>