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drm/panthor: Make sure we handle 'unknown group state' case properly

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When we check for state values returned by the FW, we only cover part of
the 0:7 range. Make sure we catch FW inconsistencies by adding a default
to the switch statement, and flagging the group state as unknown in that
case.

When an unknown state is detected, we trigger a reset, and consider the
group as unusable after that point, to prevent the potential corruption
from creeping in other places if we continue executing stuff on this
context.

v2:
- Add Steve's R-b
- Fix commit message

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/dri-devel/3b7fd2f2-679e-440c-81cd-42fc2573b515@moroto.mountain/T/#u
Suggested-by: Steven Price <steven.price@arm.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240502155248.1430582-1-boris.brezillon@collabora.com
This commit is contained in:
Boris Brezillon 2024-05-02 17:52:48 +02:00
parent 08f441360f
commit 8bdbd8b558
1 changed files with 35 additions and 2 deletions
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37
drivers/gpu/drm/panthor/panthor_sched.c
View File

@ -490,6 +490,18 @@ enum panthor_group_state {
* Can no longer be scheduled. The only allowed action is a destruction.
*/
PANTHOR_CS_GROUP_TERMINATED,
/**
* @PANTHOR_CS_GROUP_UNKNOWN_STATE: Group is an unknown state.
*
* The FW returned an inconsistent state. The group is flagged unusable
* and can no longer be scheduled. The only allowed action is a
* destruction.
*
* When that happens, we also schedule a FW reset, to start from a fresh
* state.
*/
PANTHOR_CS_GROUP_UNKNOWN_STATE,
};
/**
@ -1127,6 +1139,7 @@ csg_slot_sync_state_locked(struct panthor_device *ptdev, u32 csg_id)
struct panthor_fw_csg_iface *csg_iface;
struct panthor_group *group;
enum panthor_group_state new_state, old_state;
u32 csg_state;
lockdep_assert_held(&ptdev->scheduler->lock);
@ -1137,7 +1150,8 @@ csg_slot_sync_state_locked(struct panthor_device *ptdev, u32 csg_id)
return;
old_state = group->state;
switch (csg_iface->output->ack & CSG_STATE_MASK) {
csg_state = csg_iface->output->ack & CSG_STATE_MASK;
switch (csg_state) {
case CSG_STATE_START:
case CSG_STATE_RESUME:
new_state = PANTHOR_CS_GROUP_ACTIVE;
@ -1148,11 +1162,28 @@ csg_slot_sync_state_locked(struct panthor_device *ptdev, u32 csg_id)
case CSG_STATE_SUSPEND:
new_state = PANTHOR_CS_GROUP_SUSPENDED;
break;
default:
/* The unknown state might be caused by a FW state corruption,
* which means the group metadata can't be trusted anymore, and
* the SUSPEND operation might propagate the corruption to the
* suspend buffers. Flag the group state as unknown to make
* sure it's unusable after that point.
*/
drm_err(&ptdev->base, "Invalid state on CSG %d (state=%d)",
csg_id, csg_state);
new_state = PANTHOR_CS_GROUP_UNKNOWN_STATE;
break;
}
if (old_state == new_state)
return;
/* The unknown state might be caused by a FW issue, reset the FW to
* take a fresh start.
*/
if (new_state == PANTHOR_CS_GROUP_UNKNOWN_STATE)
panthor_device_schedule_reset(ptdev);
if (new_state == PANTHOR_CS_GROUP_SUSPENDED)
csg_slot_sync_queues_state_locked(ptdev, csg_id);
@ -1783,6 +1814,7 @@ static bool
group_can_run(struct panthor_group *group)
{
return group->state != PANTHOR_CS_GROUP_TERMINATED &&
group->state != PANTHOR_CS_GROUP_UNKNOWN_STATE &&
!group->destroyed && group->fatal_queues == 0 &&
!group->timedout;
}
@ -2557,7 +2589,8 @@ void panthor_sched_suspend(struct panthor_device *ptdev)
if (csg_slot->group) {
csgs_upd_ctx_queue_reqs(ptdev, &upd_ctx, i,
CSG_STATE_SUSPEND,
group_can_run(csg_slot->group) ?
CSG_STATE_SUSPEND : CSG_STATE_TERMINATE,
CSG_STATE_MASK);
}
}