Re: [Qemu-devel] [PATCH v2 14/16] target/arm: Hoist store to flags output in cpu_get_tb_cpu_state

["Alex Bennée" <alex.bennee@linaro.org>]

Richard Henderson <richard.henderson@linaro.org> writes:

> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

But it would be nice to resurrect Paolo's tb state caching series as
this is an expensive function to re-compute everytime.

> ---
>  target/arm/helper.c | 35 +++++++++++++++++++----------------
>  1 file changed, 19 insertions(+), 16 deletions(-)
>
> diff --git a/target/arm/helper.c b/target/arm/helper.c
> index 9e673bb672..c0e5f321c5 100644
> --- a/target/arm/helper.c
> +++ b/target/arm/helper.c
> @@ -11768,34 +11768,36 @@ static inline int fp_exception_el(CPUARMState *env)
>  }
>
>  void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc,
> -                          target_ulong *cs_base, uint32_t *flags)
> +                          target_ulong *cs_base, uint32_t *pflags)
>  {
>      ARMMMUIdx mmu_idx = core_to_arm_mmu_idx(env, cpu_mmu_index(env, false));
> +    uint32_t flags;
> +
>      if (is_a64(env)) {
>          *pc = env->pc;
> -        *flags = ARM_TBFLAG_AARCH64_STATE_MASK;
> +        flags = ARM_TBFLAG_AARCH64_STATE_MASK;
>          /* Get control bits for tagged addresses */
> -        *flags |= (arm_regime_tbi0(env, mmu_idx) << ARM_TBFLAG_TBI0_SHIFT);
> -        *flags |= (arm_regime_tbi1(env, mmu_idx) << ARM_TBFLAG_TBI1_SHIFT);
> +        flags |= (arm_regime_tbi0(env, mmu_idx) << ARM_TBFLAG_TBI0_SHIFT);
> +        flags |= (arm_regime_tbi1(env, mmu_idx) << ARM_TBFLAG_TBI1_SHIFT);
>      } else {
>          *pc = env->regs[15];
> -        *flags = (env->thumb << ARM_TBFLAG_THUMB_SHIFT)
> +        flags = (env->thumb << ARM_TBFLAG_THUMB_SHIFT)
>              | (env->vfp.vec_len << ARM_TBFLAG_VECLEN_SHIFT)
>              | (env->vfp.vec_stride << ARM_TBFLAG_VECSTRIDE_SHIFT)
>              | (env->condexec_bits << ARM_TBFLAG_CONDEXEC_SHIFT)
>              | (arm_sctlr_b(env) << ARM_TBFLAG_SCTLR_B_SHIFT);
>          if (!(access_secure_reg(env))) {
> -            *flags |= ARM_TBFLAG_NS_MASK;
> +            flags |= ARM_TBFLAG_NS_MASK;
>          }
>          if (env->vfp.xregs[ARM_VFP_FPEXC] & (1 << 30)
>              || arm_el_is_aa64(env, 1)) {
> -            *flags |= ARM_TBFLAG_VFPEN_MASK;
> +            flags |= ARM_TBFLAG_VFPEN_MASK;
>          }
> -        *flags |= (extract32(env->cp15.c15_cpar, 0, 2)
> -                   << ARM_TBFLAG_XSCALE_CPAR_SHIFT);
> +        flags |= (extract32(env->cp15.c15_cpar, 0, 2)
> +                  << ARM_TBFLAG_XSCALE_CPAR_SHIFT);
>      }
>
> -    *flags |= (arm_to_core_mmu_idx(mmu_idx) << ARM_TBFLAG_MMUIDX_SHIFT);
> +    flags |= (arm_to_core_mmu_idx(mmu_idx) << ARM_TBFLAG_MMUIDX_SHIFT);
>
>      /* The SS_ACTIVE and PSTATE_SS bits correspond to the state machine
>       * states defined in the ARM ARM for software singlestep:
> @@ -11805,25 +11807,26 @@ void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc,
>       *     1            1       Active-not-pending
>       */
>      if (arm_singlestep_active(env)) {
> -        *flags |= ARM_TBFLAG_SS_ACTIVE_MASK;
> +        flags |= ARM_TBFLAG_SS_ACTIVE_MASK;
>          if (is_a64(env)) {
>              if (env->pstate & PSTATE_SS) {
> -                *flags |= ARM_TBFLAG_PSTATE_SS_MASK;
> +                flags |= ARM_TBFLAG_PSTATE_SS_MASK;
>              }
>          } else {
>              if (env->uncached_cpsr & PSTATE_SS) {
> -                *flags |= ARM_TBFLAG_PSTATE_SS_MASK;
> +                flags |= ARM_TBFLAG_PSTATE_SS_MASK;
>              }
>          }
>      }
>      if (arm_cpu_data_is_big_endian(env)) {
> -        *flags |= ARM_TBFLAG_BE_DATA_MASK;
> +        flags |= ARM_TBFLAG_BE_DATA_MASK;
>      }
> -    *flags |= fp_exception_el(env) << ARM_TBFLAG_FPEXC_EL_SHIFT;
> +    flags |= fp_exception_el(env) << ARM_TBFLAG_FPEXC_EL_SHIFT;
>
>      if (arm_v7m_is_handler_mode(env)) {
> -        *flags |= ARM_TBFLAG_HANDLER_MASK;
> +        flags |= ARM_TBFLAG_HANDLER_MASK;
>      }
>
> +    *pflags = flags;
>      *cs_base = 0;
>  }


--
Alex Bennée