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-rw-r--r--drivers/gpu/drm/panthor/panthor_mmu.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c
index 41604a7aaf85..888fafc938a7 100644
--- a/drivers/gpu/drm/panthor/panthor_mmu.c
+++ b/drivers/gpu/drm/panthor/panthor_mmu.c
@@ -1638,6 +1638,25 @@ static int panthor_vm_lock_region(struct panthor_vm *vm, u64 start, u64 size)
start + size <= vm->locked_region.start + vm->locked_region.size)
return 0;
+ /* sm_step_remap() may need a locked region that isn't a strict superset
+ * of the original one because of having to extend unmap boundaries beyond
+ * it to deal with partial unmaps of transparent huge pages. What we want
+ * in those cases is to lock the union of both regions. The new region must
+ * always overlap with the original one, because the upper and lower unmap
+ * boundaries in a remap operation can only shift up or down respectively,
+ * but never otherwise.
+ */
+ if (vm->locked_region.size) {
+ u64 end = max(vm->locked_region.start + vm->locked_region.size,
+ start + size);
+
+ drm_WARN_ON_ONCE(&vm->ptdev->base, (start + size <= vm->locked_region.start) ||
+ (start >= vm->locked_region.start + vm->locked_region.size));
+
+ start = min(start, vm->locked_region.start);
+ size = end - start;
+ }
+
mutex_lock(&ptdev->mmu->as.slots_lock);
if (vm->as.id >= 0 && size) {
/* Lock the region that needs to be updated */