Re: [PATCH] drm/amdgpu: fix error handling in df_v3_6_pmc_start

[Alex Deucher]

On Mon, Jun 17, 2019 at 8:57 AM Arnd Bergmann <arnd@xxxxxxxx> wrote:
>
> When df_v3_6_pmc_get_ctrl_settings() fails for some reason, we
> store uninitialized data in a register, as gcc points out:
>
> drivers/gpu/drm/amd/amdgpu/df_v3_6.c: In function 'df_v3_6_pmc_start':
> drivers/gpu/drm/amd/amdgpu/amdgpu.h:1012:29: error: 'lo_val' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>  #define WREG32_PCIE(reg, v) adev->pcie_wreg(adev, (reg), (v))
>                              ^~~~
> drivers/gpu/drm/amd/amdgpu/df_v3_6.c:334:39: note: 'lo_val' was declared here
>   uint32_t lo_base_addr, hi_base_addr, lo_val, hi_val;
>                                        ^~~~~~
>
> Make it return a proper error code that we can catch in the caller.
>
> Fixes: 992af942a6cf ("drm/amdgpu: add df perfmon regs and funcs for xgmi")
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>

Applied.  thanks!

Alex

> ---
>  drivers/gpu/drm/amd/amdgpu/df_v3_6.c | 13 +++++++++----
>  1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/df_v3_6.c b/drivers/gpu/drm/amd/amdgpu/df_v3_6.c
> index 8c09bf994acd..e079ee066d87 100644
> --- a/drivers/gpu/drm/amd/amdgpu/df_v3_6.c
> +++ b/drivers/gpu/drm/amd/amdgpu/df_v3_6.c
> @@ -177,7 +177,7 @@ static void df_v3_6_pmc_get_read_settings(struct amdgpu_device *adev,
>  }
>
>  /* get control counter settings i.e. address and values to set */
> -static void df_v3_6_pmc_get_ctrl_settings(struct amdgpu_device *adev,
> +static int df_v3_6_pmc_get_ctrl_settings(struct amdgpu_device *adev,
>                                           uint64_t config,
>                                           uint32_t *lo_base_addr,
>                                           uint32_t *hi_base_addr,
> @@ -191,12 +191,12 @@ static void df_v3_6_pmc_get_ctrl_settings(struct amdgpu_device *adev,
>         df_v3_6_pmc_get_addr(adev, config, 1, lo_base_addr, hi_base_addr);
>
>         if (lo_val == NULL || hi_val == NULL)
> -               return;
> +               return -EINVAL;
>
>         if ((*lo_base_addr == 0) || (*hi_base_addr == 0)) {
>                 DRM_ERROR("DF PMC addressing not retrieved! Lo: %x, Hi: %x",
>                                 *lo_base_addr, *hi_base_addr);
> -               return;
> +               return -ENXIO;
>         }
>
>         eventsel = GET_EVENT(config);
> @@ -211,6 +211,8 @@ static void df_v3_6_pmc_get_ctrl_settings(struct amdgpu_device *adev,
>         es_7_0 = es_13_0 & 0x0FFUL;
>         *lo_val = (es_7_0 & 0xFFUL) | ((unitmask & 0x0FUL) << 8);
>         *hi_val = (es_11_8 | ((es_13_12)<<(29)));
> +
> +       return 0;
>  }
>
>  /* assign df performance counters for read */
> @@ -345,13 +347,16 @@ static int df_v3_6_add_xgmi_link_cntr(struct amdgpu_device *adev,
>         if (ret || is_assigned)
>                 return ret;
>
> -       df_v3_6_pmc_get_ctrl_settings(adev,
> +       ret = df_v3_6_pmc_get_ctrl_settings(adev,
>                         config,
>                         &lo_base_addr,
>                         &hi_base_addr,
>                         &lo_val,
>                         &hi_val);
>
> +       if (ret)
> +               return ret;
> +
>         WREG32_PCIE(lo_base_addr, lo_val);
>         WREG32_PCIE(hi_base_addr, hi_val);
>
> --
> 2.20.0
>
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