[PATCH v3] drm/amd/pm: avoid potential UBSAN issue on legacy asics

[Deucher, Alexander]

[Public]

> -----Original Message-----
> From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of
> Guchun Chen
> Sent: Tuesday, May 9, 2023 4:02 AM
> To: amd-gfx at lists.freedesktop.org; Deucher, Alexander
> <Alexander.Deucher at amd.com>; Zhang, Hawking
> <Hawking.Zhang at amd.com>; Lazar, Lijo <Lijo.Lazar at amd.com>; Quan, Evan
> <Evan.Quan at amd.com>
> Cc: Chen, Guchun <Guchun.Chen at amd.com>
> Subject: [PATCH v3] drm/amd/pm: avoid potential UBSAN issue on legacy
> asics
> 
> Prevent further dpm casting on legacy asics without od_enabled in
> amdgpu_dpm_is_overdrive_supported. This can avoid UBSAN complain in
> init sequence.
> 
> v2: add a macro to check legacy dpm instead of checking asic family/type
> v3: refine macro name for naming consistency
> 
> Suggested-by: Evan Quan <evan.quan at amd.com>
> Signed-off-by: Guchun Chen <guchun.chen at amd.com>
> Reviewed-by: Lijo Lazar <lijo.lazar at amd.com>

Acked-by: Alex Deucher <alexander.deucher at amd.com>

> ---
>  drivers/gpu/drm/amd/pm/amdgpu_dpm.c | 9 +++++++--
>  1 file changed, 7 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..078aaaa53162 100644
> --- a/drivers/gpu/drm/amd/pm/amdgpu_dpm.c
> +++ b/drivers/gpu/drm/amd/pm/amdgpu_dpm.c
> @@ -36,6 +36,8 @@
>  #define amdgpu_dpm_enable_bapm(adev, e) \
>  		((adev)->powerplay.pp_funcs->enable_bapm((adev)-
> >powerplay.pp_handle, (e)))
> 
> +#define amdgpu_dpm_is_legacy_dpm(adev) ((adev)-
> >powerplay.pp_handle ==
> +(adev))
> +
>  int amdgpu_dpm_get_sclk(struct amdgpu_device *adev, bool low)  {
>  	const struct amd_pm_funcs *pp_funcs = adev-
> >powerplay.pp_funcs; @@ -1467,8 +1469,11 @@ int
> amdgpu_dpm_is_overdrive_supported(struct amdgpu_device *adev)
>  	} else {
>  		struct pp_hwmgr *hwmgr;
> 
> -		/* SI asic does not carry od_enabled */
> -		if (adev->family == AMDGPU_FAMILY_SI)
> +		/*
> +		 * dpm on some legacy asics don't carry od_enabled member
> +		 * as its pp_handle is casted directly from adev.
> +		 */
> +		if (amdgpu_dpm_is_legacy_dpm(adev))
>  			return false;
> 
>  		hwmgr = (struct pp_hwmgr *)adev->powerplay.pp_handle;
> --
> 2.25.1