Hi Boris,
On 12/2/25 13:35, Boris Brezillon wrote:
An AS can be disabled in the middle of a VM operation (VM being
evicted from an AS slot, for instance). In that case, we need the
locked section to be unlocked before releasing the slot.
Fixes: 6e2d3b3e8589 ("drm/panthor: Add support for atomic page table updates")
Signed-off-by: Boris Brezillon <[email protected]>
---
drivers/gpu/drm/panthor/panthor_mmu.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c
b/drivers/gpu/drm/panthor/panthor_mmu.c
index 3644af1a8e56..4ed28bd1b8ec 100644
--- a/drivers/gpu/drm/panthor/panthor_mmu.c
+++ b/drivers/gpu/drm/panthor/panthor_mmu.c
@@ -588,6 +588,7 @@ static int panthor_mmu_as_enable(struct panthor_device
*ptdev, u32 as_nr,
static int panthor_mmu_as_disable(struct panthor_device *ptdev, u32 as_nr,
bool recycle_slot)
{
+ struct panthor_vm *vm = ptdev->mmu->as.slots[as_nr].vm;
int ret;
Thanks for the fix.
Please can you consider adding a lockdep_assert_held for
mmu->as.slots_lock. That would in a way make it explicit that it is safe
to de-reference vm pointer here.
Best regards
Akash
/* Flush+invalidate RW caches, invalidate RO ones. */
@@ -596,6 +597,16 @@ static int panthor_mmu_as_disable(struct panthor_device
*ptdev, u32 as_nr,
if (ret)
return ret;
+ if (vm && vm->locked_region.size) {
+ /* Unlock the region if there a lock pending. */
+ ret = as_send_cmd_and_wait(ptdev, vm->as.id, AS_COMMAND_UNLOCK);
+ if (ret)
+ return ret;
+
+ vm->locked_region.start = 0;
+ vm->locked_region.size = 0;
+ }
+
/* If the slot is going to be used immediately, don't bother changing
* the config.
*/
