[PATCH 1/3] drm/amd/pm: Fix negative array index read warning for pptable->DpmDescriptor

[Huang, Tim]

[AMD Official Use Only - General]

> -----Original Message-----
> From: Jesse Zhang <jesse.zhang at amd.com>
> Sent: Friday, April 26, 2024 3:28 PM
> To: amd-gfx at lists.freedesktop.org
> Cc: Deucher, Alexander <Alexander.Deucher at amd.com>; Koenig, Christian
> <Christian.Koenig at amd.com>; Huang, Tim <Tim.Huang at amd.com>; Zhang,
> Jesse(Jie) <Jesse.Zhang at amd.com>; Zhang, Jesse(Jie)
> <Jesse.Zhang at amd.com>
> Subject: [PATCH 1/3] drm/amd/pm: Fix negative array index read warning for
> pptable->DpmDescriptor
>
> Avoid using the negative values
> for clk_idex as an index into an array pptable->DpmDescriptor.
>
> Signed-off-by: Jesse Zhang <Jesse.Zhang at amd.com>
> ---
>  .../gpu/drm/amd/pm/swsmu/smu11/navi10_ppt.c   | 25 +++++++++++++++---
> -
>  1 file changed, 20 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu11/navi10_ppt.c
> b/drivers/gpu/drm/amd/pm/swsmu/smu11/navi10_ppt.c
> index 5a68d365967f..cd88d2c3841a 100644
> --- a/drivers/gpu/drm/amd/pm/swsmu/smu11/navi10_ppt.c
> +++ b/drivers/gpu/drm/amd/pm/swsmu/smu11/navi10_ppt.c
> @@ -1219,15 +1219,18 @@ static int
> navi10_get_current_clk_freq_by_table(struct smu_context *smu,
>                                          value);
>  }
>
> -static bool navi10_is_support_fine_grained_dpm(struct smu_context *smu,
> enum smu_clk_type clk_type)
> +static int navi10_is_support_fine_grained_dpm(struct smu_context *smu,
> +enum smu_clk_type clk_type)
>  {
>       PPTable_t *pptable = smu->smu_table.driver_pptable;
>       DpmDescriptor_t *dpm_desc = NULL;
> -     uint32_t clk_index = 0;
> +     int clk_index = 0;
>
>       clk_index = smu_cmn_to_asic_specific_index(smu,
>                                                  CMN2ASIC_MAPPING_CLK,
>                                                  clk_type);
> +     if(clk_index)
Hi jesse,

If should only be "if(clk_index < 0)" to return an error.

Tim

> +             return clk_index;

> +
>       dpm_desc = &pptable->DpmDescriptor[clk_index];
>
>       /* 0 - Fine grained DPM, 1 - Discrete DPM */ @@ -1287,7 +1290,11
> @@ static int navi10_emit_clk_levels(struct smu_context *smu,
>               if (ret)
>                       return ret;
>
> -             if (!navi10_is_support_fine_grained_dpm(smu, clk_type)) {
> +             ret = navi10_is_support_fine_grained_dpm(smu, clk_type);
> +             if (ret < 0)
> +                     return ret;
> +
> +             if (!ret) {
>                       for (i = 0; i < count; i++) {
>                               ret =
> smu_v11_0_get_dpm_freq_by_index(smu,
>                                                                     clk_type, i,
> &value);
> @@ -1496,7 +1503,11 @@ static int navi10_print_clk_levels(struct
> smu_context *smu,
>               if (ret)
>                       return size;
>
> -             if (!navi10_is_support_fine_grained_dpm(smu, clk_type)) {
> +             ret = navi10_is_support_fine_grained_dpm(smu, clk_type);
> +             if (ret < 0)
> +                     return ret;
> +
> +             if (!ret) {
>                       for (i = 0; i < count; i++) {
>                               ret =
> smu_v11_0_get_dpm_freq_by_index(smu, clk_type, i, &value);
>                               if (ret)
> @@ -1665,7 +1676,11 @@ static int navi10_force_clk_levels(struct
> smu_context *smu,
>       case SMU_UCLK:
>       case SMU_FCLK:
>               /* There is only 2 levels for fine grained DPM */
> -             if (navi10_is_support_fine_grained_dpm(smu, clk_type)) {
> +             ret = navi10_is_support_fine_grained_dpm(smu, clk_type);
> +             if (ret < 0)
> +                     return ret;
> +
> +             if (ret) {
>                       soft_max_level = (soft_max_level >= 1 ? 1 : 0);
>                       soft_min_level = (soft_min_level >= 1 ? 1 : 0);
>               }
> --
> 2.25.1