Re: [Qemu-devel] [PATCH 4/4] target-arm: refactor cp15.c13 register access

[Laurent Desnogues <laurent.desnogues@gmail.com>]

On Wed, Jan 27, 2010 at 1:49 PM, Riku Voipio <riku.voipio@iki.fi> wrote:
> From: Riku Voipio <riku.voipio@nokia.com>
>
> Access the cp15.c13 TLS registers directly with TCG ops instead of with
> a slow helper. If the the cp15 read/write was not TLS register access,
> fall back to the cp15 helper.
>
> This makes accessing __thread variables in linux-user when apps are compiled
> with -mtp=cp15 possible. legal cp15 register to acces from linux-user are
> already checked in cp15_user_ok.
>
> While at it, make the cp15.c13 Thread ID registers available only on
> ARMv6K and newer.
>
> Signed-off-by: Riku Voipio <riku.voipio@nokia.com>

Acked-by: Laurent Desnogues <laurent.desnogues@gmail.com>


Laurent

> ---
>  target-arm/helper.c    |   16 --------------
>  target-arm/translate.c |   55 ++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 55 insertions(+), 16 deletions(-)
>
> diff --git a/target-arm/helper.c b/target-arm/helper.c
> index b3aec99..27001e8 100644
> --- a/target-arm/helper.c
> +++ b/target-arm/helper.c
> @@ -511,7 +511,6 @@ void HELPER(set_cp15)(CPUState *env, uint32_t insn, uint32_t val)
>  uint32_t HELPER(get_cp15)(CPUState *env, uint32_t insn)
>  {
>     cpu_abort(env, "cp15 insn %08x\n", insn);
> -    return 0;
>  }
>
>  /* These should probably raise undefined insn exceptions.  */
> @@ -1491,15 +1490,6 @@ void HELPER(set_cp15)(CPUState *env, uint32_t insn, uint32_t val)
>               tlb_flush(env, 0);
>             env->cp15.c13_context = val;
>             break;
> -        case 2:
> -            env->cp15.c13_tls1 = val;
> -            break;
> -        case 3:
> -            env->cp15.c13_tls2 = val;
> -            break;
> -        case 4:
> -            env->cp15.c13_tls3 = val;
> -            break;
>         default:
>             goto bad_reg;
>         }
> @@ -1779,12 +1769,6 @@ uint32_t HELPER(get_cp15)(CPUState *env, uint32_t insn)
>             return env->cp15.c13_fcse;
>         case 1:
>             return env->cp15.c13_context;
> -        case 2:
> -            return env->cp15.c13_tls1;
> -        case 3:
> -            return env->cp15.c13_tls2;
> -        case 4:
> -            return env->cp15.c13_tls3;
>         default:
>             goto bad_reg;
>         }
> diff --git a/target-arm/translate.c b/target-arm/translate.c
> index 5cf3e06..786c329 100644
> --- a/target-arm/translate.c
> +++ b/target-arm/translate.c
> @@ -2455,6 +2455,57 @@ static int cp15_user_ok(uint32_t insn)
>     return 0;
>  }
>
> +static int cp15_tls_load_store(CPUState *env, DisasContext *s, uint32_t insn, uint32_t rd)
> +{
> +    TCGv tmp;
> +    int cpn = (insn >> 16) & 0xf;
> +    int cpm = insn & 0xf;
> +    int op = ((insn >> 5) & 7) | ((insn >> 18) & 0x38);
> +
> +    if (!arm_feature(env, ARM_FEATURE_V6K))
> +        return 0;
> +
> +    if (!(cpn == 13 && cpm == 0))
> +        return 0;
> +
> +    if (insn & ARM_CP_RW_BIT) {
> +        tmp = new_tmp();
> +        switch (op) {
> +        case 2:
> +            tcg_gen_ld_i32(tmp, cpu_env, offsetof(CPUARMState, cp15.c13_tls1));
> +            break;
> +        case 3:
> +            tcg_gen_ld_i32(tmp, cpu_env, offsetof(CPUARMState, cp15.c13_tls2));
> +            break;
> +        case 4:
> +            tcg_gen_ld_i32(tmp, cpu_env, offsetof(CPUARMState, cp15.c13_tls3));
> +            break;
> +        default:
> +            dead_tmp(tmp);
> +            return 0;
> +        }
> +        store_reg(s, rd, tmp);
> +
> +    } else {
> +        tmp = load_reg(s, rd);
> +        switch (op) {
> +        case 2:
> +            tcg_gen_st_i32(tmp, cpu_env, offsetof(CPUARMState, cp15.c13_tls1));
> +            break;
> +        case 3:
> +            tcg_gen_st_i32(tmp, cpu_env, offsetof(CPUARMState, cp15.c13_tls2));
> +            break;
> +        case 4:
> +            tcg_gen_st_i32(tmp, cpu_env, offsetof(CPUARMState, cp15.c13_tls3));
> +            break;
> +        default:
> +            return 0;
> +        }
> +        dead_tmp(tmp);
> +    }
> +    return 1;
> +}
> +
>  /* Disassemble system coprocessor (cp15) instruction.  Return nonzero if
>    instruction is not defined.  */
>  static int disas_cp15_insn(CPUState *env, DisasContext *s, uint32_t insn)
> @@ -2489,6 +2540,10 @@ static int disas_cp15_insn(CPUState *env, DisasContext *s, uint32_t insn)
>         return 0;
>     }
>     rd = (insn >> 12) & 0xf;
> +
> +    if (cp15_tls_load_store(env, s, insn, rd))
> +        return 0;
> +
>     tmp2 = tcg_const_i32(insn);
>     if (insn & ARM_CP_RW_BIT) {
>         tmp = new_tmp();
> --
> 1.6.5
>
>
>
>