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

[Lazar, Lijo]

On 5/9/2023 10:59 AM, Guchun Chen wrote:

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

Suggested-by: Evan Quan <evan.q...@amd.com>
Signed-off-by: Guchun Chen <guchun.c...@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..4b28fd62ed7a 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 is_legacy_dpm(adev) ((adev)->powerplay.pp_handle == (adev))

+

For consistent naming, you may use amdgpu_dpm_is_legacy_dpm().

Regardless,

Reviewed-by: Lijo Lazar <lijo.la...@amd.com>

Thanks,
Lijo

  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 (is_legacy_dpm(adev))
                        return false;

hwmgr = (struct pp_hwmgr *)adev->powerplay.pp_handle;