Re: [PATCH v2 4/7] target/riscv: Check nanboxed inputs to fp helpers

[LIU Zhiwei]

On 2020/7/24 8:28, Richard Henderson wrote:
> If a 32-bit input is not properly nanboxed, then the input is
> replaced with the default qnan.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   target/riscv/internals.h  | 11 +++++++
>   target/riscv/fpu_helper.c | 64 ++++++++++++++++++++++++++++-----------
>   2 files changed, 57 insertions(+), 18 deletions(-)
>
> diff --git a/target/riscv/internals.h b/target/riscv/internals.h
> index 9f4ba7d617..f1a546dba6 100644
> --- a/target/riscv/internals.h
> +++ b/target/riscv/internals.h
> @@ -43,4 +43,15 @@ static inline uint64_t nanbox_s(float32 f)
>       return f | MAKE_64BIT_MASK(32, 32);
>   }
>   
> +static inline float32 check_nanbox_s(uint64_t f)
> +{
> +    uint64_t mask = MAKE_64BIT_MASK(32, 32);
> +
> +    if (likely((f & mask) == mask)) {
> +        return (uint32_t)f;
> +    } else {
> +        return 0x7fc00000u; /* default qnan */
> +    }
> +}
> +
If possible,

+static inline float32 check_nanbox(uint64_t f, uint32_t flen)
+{
+    uint64_t mask = MAKE_64BIT_MASK(flen, 64 - flen);
+
+    if (likely((f & mask) == mask)) {
+        return (uint32_t)f;
+    } else {
+        return (flen == 32) ? 0x7fc00000u : 0x7e00u; /* default qnan */
+    }
+}
+

Reviewed-by: LIU Zhiwei <zhiwei_liu@c-sky.com>

Zhiwei
>   #endif
> diff --git a/target/riscv/fpu_helper.c b/target/riscv/fpu_helper.c
> index 72541958a7..bb346a8249 100644
> --- a/target/riscv/fpu_helper.c
> +++ b/target/riscv/fpu_helper.c
> @@ -81,9 +81,12 @@ void helper_set_rounding_mode(CPURISCVState *env, uint32_t 
> rm)
>       set_float_rounding_mode(softrm, &env->fp_status);
>   }
>   
> -static uint64_t do_fmadd_s(CPURISCVState *env, uint64_t frs1, uint64_t frs2,
> -                           uint64_t frs3, int flags)
> +static uint64_t do_fmadd_s(CPURISCVState *env, uint64_t rs1, uint64_t rs2,
> +                           uint64_t rs3, int flags)
>   {
> +    float32 frs1 = check_nanbox_s(rs1);
> +    float32 frs2 = check_nanbox_s(rs2);
> +    float32 frs3 = check_nanbox_s(rs3);
>       return nanbox_s(float32_muladd(frs1, frs2, frs3, flags, &env->fp_status));
>   }
>   
> @@ -139,74 +142,97 @@ uint64_t helper_fnmadd_d(CPURISCVState *env, uint64_t frs1, uint64_t frs2,
>                             float_muladd_negate_product, &env->fp_status);
>   }
>   
> -uint64_t helper_fadd_s(CPURISCVState *env, uint64_t frs1, uint64_t frs2)
> +uint64_t helper_fadd_s(CPURISCVState *env, uint64_t rs1, uint64_t rs2)
>   {
> +    float32 frs1 = check_nanbox_s(rs1);
> +    float32 frs2 = check_nanbox_s(rs2);
>       return nanbox_s(float32_add(frs1, frs2, &env->fp_status));
>   }
>   
> -uint64_t helper_fsub_s(CPURISCVState *env, uint64_t frs1, uint64_t frs2)
> +uint64_t helper_fsub_s(CPURISCVState *env, uint64_t rs1, uint64_t rs2)
>   {
> +    float32 frs1 = check_nanbox_s(rs1);
> +    float32 frs2 = check_nanbox_s(rs2);
>       return nanbox_s(float32_sub(frs1, frs2, &env->fp_status));
>   }
>   
> -uint64_t helper_fmul_s(CPURISCVState *env, uint64_t frs1, uint64_t frs2)
> +uint64_t helper_fmul_s(CPURISCVState *env, uint64_t rs1, uint64_t rs2)
>   {
> +    float32 frs1 = check_nanbox_s(rs1);
> +    float32 frs2 = check_nanbox_s(rs2);
>       return nanbox_s(float32_mul(frs1, frs2, &env->fp_status));
>   }
>   
> -uint64_t helper_fdiv_s(CPURISCVState *env, uint64_t frs1, uint64_t frs2)
> +uint64_t helper_fdiv_s(CPURISCVState *env, uint64_t rs1, uint64_t rs2)
>   {
> +    float32 frs1 = check_nanbox_s(rs1);
> +    float32 frs2 = check_nanbox_s(rs2);
>       return nanbox_s(float32_div(frs1, frs2, &env->fp_status));
>   }
>   
> -uint64_t helper_fmin_s(CPURISCVState *env, uint64_t frs1, uint64_t frs2)
> +uint64_t helper_fmin_s(CPURISCVState *env, uint64_t rs1, uint64_t rs2)
>   {
> +    float32 frs1 = check_nanbox_s(rs1);
> +    float32 frs2 = check_nanbox_s(rs2);
>       return nanbox_s(float32_minnum(frs1, frs2, &env->fp_status));
>   }
>   
> -uint64_t helper_fmax_s(CPURISCVState *env, uint64_t frs1, uint64_t frs2)
> +uint64_t helper_fmax_s(CPURISCVState *env, uint64_t rs1, uint64_t rs2)
>   {
> +    float32 frs1 = check_nanbox_s(rs1);
> +    float32 frs2 = check_nanbox_s(rs2);
>       return nanbox_s(float32_maxnum(frs1, frs2, &env->fp_status));
>   }
>   
> -uint64_t helper_fsqrt_s(CPURISCVState *env, uint64_t frs1)
> +uint64_t helper_fsqrt_s(CPURISCVState *env, uint64_t rs1)
>   {
> +    float32 frs1 = check_nanbox_s(rs1);
>       return nanbox_s(float32_sqrt(frs1, &env->fp_status));
>   }
>   
> -target_ulong helper_fle_s(CPURISCVState *env, uint64_t frs1, uint64_t frs2)
> +target_ulong helper_fle_s(CPURISCVState *env, uint64_t rs1, uint64_t rs2)
>   {
> +    float32 frs1 = check_nanbox_s(rs1);
> +    float32 frs2 = check_nanbox_s(rs2);
>       return float32_le(frs1, frs2, &env->fp_status);
>   }
>   
> -target_ulong helper_flt_s(CPURISCVState *env, uint64_t frs1, uint64_t frs2)
> +target_ulong helper_flt_s(CPURISCVState *env, uint64_t rs1, uint64_t rs2)
>   {
> +    float32 frs1 = check_nanbox_s(rs1);
> +    float32 frs2 = check_nanbox_s(rs2);
>       return float32_lt(frs1, frs2, &env->fp_status);
>   }
>   
> -target_ulong helper_feq_s(CPURISCVState *env, uint64_t frs1, uint64_t frs2)
> +target_ulong helper_feq_s(CPURISCVState *env, uint64_t rs1, uint64_t rs2)
>   {
> +    float32 frs1 = check_nanbox_s(rs1);
> +    float32 frs2 = check_nanbox_s(rs2);
>       return float32_eq_quiet(frs1, frs2, &env->fp_status);
>   }
>   
> -target_ulong helper_fcvt_w_s(CPURISCVState *env, uint64_t frs1)
> +target_ulong helper_fcvt_w_s(CPURISCVState *env, uint64_t rs1)
>   {
> +    float32 frs1 = check_nanbox_s(rs1);
>       return float32_to_int32(frs1, &env->fp_status);
>   }
>   
> -target_ulong helper_fcvt_wu_s(CPURISCVState *env, uint64_t frs1)
> +target_ulong helper_fcvt_wu_s(CPURISCVState *env, uint64_t rs1)
>   {
> +    float32 frs1 = check_nanbox_s(rs1);
>       return (int32_t)float32_to_uint32(frs1, &env->fp_status);
>   }
>   
>   #if defined(TARGET_RISCV64)
> -uint64_t helper_fcvt_l_s(CPURISCVState *env, uint64_t frs1)
> +uint64_t helper_fcvt_l_s(CPURISCVState *env, uint64_t rs1)
>   {
> +    float32 frs1 = check_nanbox_s(rs1);
>       return float32_to_int64(frs1, &env->fp_status);
>   }
>   
> -uint64_t helper_fcvt_lu_s(CPURISCVState *env, uint64_t frs1)
> +uint64_t helper_fcvt_lu_s(CPURISCVState *env, uint64_t rs1)
>   {
> +    float32 frs1 = check_nanbox_s(rs1);
>       return float32_to_uint64(frs1, &env->fp_status);
>   }
>   #endif
> @@ -233,8 +259,9 @@ uint64_t helper_fcvt_s_lu(CPURISCVState *env, uint64_t rs1)
>   }
>   #endif
>   
> -target_ulong helper_fclass_s(uint64_t frs1)
> +target_ulong helper_fclass_s(uint64_t rs1)
>   {
> +    float32 frs1 = check_nanbox_s(rs1);
>       return fclass_s(frs1);
>   }
>   
> @@ -275,7 +302,8 @@ uint64_t helper_fcvt_s_d(CPURISCVState *env, uint64_t rs1)
>   
>   uint64_t helper_fcvt_d_s(CPURISCVState *env, uint64_t rs1)
>   {
> -    return float32_to_float64(rs1, &env->fp_status);
> +    float32 frs1 = check_nanbox_s(rs1);
> +    return float32_to_float64(frs1, &env->fp_status);
>   }
>   
>   uint64_t helper_fsqrt_d(CPURISCVState *env, uint64_t frs1)