[PATCH] drm/amd/pm: avoid potential UBSAN issue on legacy asics

[Lazar, Lijo]

On 5/9/2023 7:12 AM, Guchun Chen wrote:
> Prevent further casting on chip MULLINS/KABINI/KAVERI when calling
> amdgpu_dpm_is_overdrive_supported, this can avoid UBSAN complain
> in init sequence.
> 
> Suggested-by: Evan Quan <evan.quan at amd.com>
> Signed-off-by: Guchun Chen <guchun.chen at amd.com>
> ---
>   drivers/gpu/drm/amd/pm/amdgpu_dpm.c | 10 ++++++++--
>   1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/pm/amdgpu_dpm.c b/drivers/gpu/drm/amd/pm/amdgpu_dpm.c
> index 86246f69dbe1..ccd3ea89eacf 100644
> --- a/drivers/gpu/drm/amd/pm/amdgpu_dpm.c
> +++ b/drivers/gpu/drm/amd/pm/amdgpu_dpm.c
> @@ -1467,8 +1467,14 @@ int amdgpu_dpm_is_overdrive_supported(struct amdgpu_device *adev)
>   	} else {
>   		struct pp_hwmgr *hwmgr;
>   

Instead of family check, what if you wrap it like -

is_legacy_dpm(adev)
	return (adev->powerplay.pp_handle == adev)

Could be useful for legacy dpm checks.

Thanks,
Lijo

> -		/* SI asic does not carry od_enabled */
> -		if (adev->family == AMDGPU_FAMILY_SI)
> +		/*
> +		 * SI asic and chip MULLINS/KABINI/KAVERI do not carry
> +		 * od_enabled, as its pp_handle is casted from adev.
> +		 */
> +		if ((adev->family == AMDGPU_FAMILY_SI) ||
> +		    (adev->asic_type == CHIP_MULLINS) ||
> +		    (adev->asic_type == CHIP_KABINI) ||
> +		    (adev->asic_type == CHIP_KAVERI))
>   			return false;
>   
>   		hwmgr = (struct pp_hwmgr *)adev->powerplay.pp_handle;