Re: [PATCH v7 5/6] [RISCV_PM] Implement address masking functions required for RISC-V Pointer Masking extension

[Alistair Francis <alistair23@gmail.com>]

On Sun, Jan 10, 2021 at 10:53 AM Alexey Baturo <baturo.alexey@gmail.com> wrote:
>
> From: Anatoly Parshintsev <kupokupokupopo@gmail.com>
>
> Signed-off-by: Anatoly Parshintsev <kupokupokupopo@gmail.com>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  target/riscv/cpu.h       | 19 +++++++++++++++++++
>  target/riscv/translate.c | 34 ++++++++++++++++++++++++++++++++--
>  2 files changed, 51 insertions(+), 2 deletions(-)
>
> diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
> index 37ea7f7802..b3c63ca5ff 100644
> --- a/target/riscv/cpu.h
> +++ b/target/riscv/cpu.h
> @@ -397,6 +397,7 @@ FIELD(TB_FLAGS, SEW, 5, 3)
>  FIELD(TB_FLAGS, VILL, 8, 1)
>  /* Is a Hypervisor instruction load/store allowed? */
>  FIELD(TB_FLAGS, HLSX, 9, 1)
> +FIELD(TB_FLAGS, PM_ENABLED, 10, 1)

Can you add a comment above this for what this is? PM could be lots of
different things.

>
>  bool riscv_cpu_is_32bit(CPURISCVState *env);
>
> @@ -454,6 +455,24 @@ static inline void cpu_get_tb_cpu_state(CPURISCVState *env, target_ulong *pc,
>              flags = FIELD_DP32(flags, TB_FLAGS, HLSX, 1);
>          }
>      }
> +    if (riscv_has_ext(env, RVJ)) {
> +        int priv = cpu_mmu_index(env, false);
> +        bool pm_enabled = false;
> +        switch (priv) {
> +        case PRV_U:
> +            pm_enabled = env->mmte & U_PM_ENABLE;
> +            break;
> +        case PRV_S:
> +            pm_enabled = env->mmte & S_PM_ENABLE;
> +            break;
> +        case PRV_M:
> +            pm_enabled = env->mmte & M_PM_ENABLE;
> +            break;
> +        default:
> +            g_assert_not_reached();
> +        }
> +        flags = FIELD_DP32(flags, TB_FLAGS, PM_ENABLED, pm_enabled);
> +    }
>  #endif
>
>      *pflags = flags;
> diff --git a/target/riscv/translate.c b/target/riscv/translate.c
> index 5da7330f33..980604935d 100644
> --- a/target/riscv/translate.c
> +++ b/target/riscv/translate.c
> @@ -36,6 +36,9 @@ static TCGv cpu_gpr[32], cpu_pc, cpu_vl;
>  static TCGv_i64 cpu_fpr[32]; /* assume F and D extensions */
>  static TCGv load_res;
>  static TCGv load_val;
> +/* globals for PM CSRs */
> +static TCGv pm_mask[4];
> +static TCGv pm_base[4];
>
>  #include "exec/gen-icount.h"
>
> @@ -64,6 +67,10 @@ typedef struct DisasContext {
>      uint16_t vlen;
>      uint16_t mlen;
>      bool vl_eq_vlmax;
> +    /* PointerMasking extension */
> +    bool pm_enabled;
> +    TCGv pm_mask;
> +    TCGv pm_base;
>  } DisasContext;
>
>  #ifdef TARGET_RISCV64
> @@ -103,13 +110,19 @@ static void gen_nanbox_s(TCGv_i64 out, TCGv_i64 in)
>  }
>
>  /*
> - * Temp stub: generates address adjustment for PointerMasking
> + * Generates address adjustment for PointerMasking
>   */
>  static void gen_pm_adjust_address(DisasContext *s,
>                                    TCGv_i64      dst,
>                                    TCGv_i64      src)
>  {
> -    tcg_gen_mov_i64(dst, src);
> +    if (!s->pm_enabled) {
> +        /* Load unmodified address */
> +        tcg_gen_mov_i64(dst, src);
> +    } else {
> +        tcg_gen_andc_i64(dst, src, s->pm_mask);
> +        tcg_gen_or_i64(dst, dst, s->pm_base);
> +    }
>  }
>
>  /*
> @@ -828,6 +841,10 @@ static void riscv_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs)
>      ctx->lmul = FIELD_EX32(tb_flags, TB_FLAGS, LMUL);
>      ctx->mlen = 1 << (ctx->sew  + 3 - ctx->lmul);
>      ctx->vl_eq_vlmax = FIELD_EX32(tb_flags, TB_FLAGS, VL_EQ_VLMAX);
> +    ctx->pm_enabled = FIELD_EX32(tb_flags, TB_FLAGS, PM_ENABLED);
> +    int priv = cpu_mmu_index(env, false);

Can you AND this with TB_FLAGS_PRIV_MMU_MASK?

Alistair

> +    ctx->pm_mask = pm_mask[priv];
> +    ctx->pm_base = pm_base[priv];
>  }
>
>  static void riscv_tr_tb_start(DisasContextBase *db, CPUState *cpu)
> @@ -947,4 +964,17 @@ void riscv_translate_init(void)
>                               "load_res");
>      load_val = tcg_global_mem_new(cpu_env, offsetof(CPURISCVState, load_val),
>                               "load_val");
> +    /* Assign PM CSRs to tcg globals */
> +    pm_mask[PRV_U] =
> +      tcg_global_mem_new(cpu_env, offsetof(CPURISCVState, upmmask), "upmmask");
> +    pm_base[PRV_U] =
> +      tcg_global_mem_new(cpu_env, offsetof(CPURISCVState, upmbase), "upmbase");
> +    pm_mask[PRV_S] =
> +      tcg_global_mem_new(cpu_env, offsetof(CPURISCVState, spmmask), "spmmask");
> +    pm_base[PRV_S] =
> +      tcg_global_mem_new(cpu_env, offsetof(CPURISCVState, spmbase), "spmbase");
> +    pm_mask[PRV_M] =
> +      tcg_global_mem_new(cpu_env, offsetof(CPURISCVState, mpmmask), "mpmmask");
> +    pm_base[PRV_M] =
> +      tcg_global_mem_new(cpu_env, offsetof(CPURISCVState, mpmbase), "mpmbase");
>  }
> --
> 2.20.1
>
>