drm/amd/amdgpu:save psp ring wptr to avoid attack

[Why]
When some tools performing psp mailbox attack, the readback value
of register can be a random value which may break psp.

[How]
Use a psp wptr cache machanism to aovid the change made by attack.

v2: unify change and add detailed reason

Signed-off-by: Victor Zhao <[email protected]>
Signed-off-by: Jingwen Chen <[email protected]>
Reviewed-by: Monk Liu <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

0 files changed, 0 insertions, 0 deletions