optee: use driver internal tee_context for some rpc

Adds a driver private tee_context by moving the tee_context in struct
optee_notif to struct optee. This tee_context was previously used when
doing internal calls to secure world to deliver notification.

The new driver internal tee_context is now also when allocating driver
private shared memory. This decouples the shared memory object from its
original tee_context. This is needed when the life time of such a memory
allocation outlives the client tee_context.

This patch fixes the problem described below:

The addition of a shutdown hook by commit f25889f93184 ("optee: fix tee out
of memory failure seen during kexec reboot") introduced a kernel shutdown
regression that can be triggered after running the OP-TEE xtest suites.

Once the shutdown hook is called it is not possible to communicate any more
with the supplicant process because the system is not scheduling task any
longer. Thus if the optee driver shutdown path receives a supplicant RPC
request from the OP-TEE we will deadlock the kernel's shutdown.

Fixes: f25889f93184 ("optee: fix tee out of memory failure seen during kexec reboot")
Fixes: 217e0250cccb ("tee: use reference counting for tee_context")
Reported-by: Lars Persson <larper@axis.com>
Cc: stable@vger.kernel.org
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
index 46f74ab07c7e..92bc47bef95f 100644
--- a/drivers/tee/optee/optee_private.h
+++ b/drivers/tee/optee/optee_private.h
@@ -53,7 +53,6 @@ struct optee_call_queue {
 
 struct optee_notif {
 	u_int max_key;
-	struct tee_context *ctx;
 	/* Serializes access to the elements below in this struct */
 	spinlock_t lock;
 	struct list_head db;
@@ -134,9 +133,10 @@ struct optee_ops {
 /**
  * struct optee - main service struct
  * @supp_teedev:	supplicant device
+ * @teedev:		client device
  * @ops:		internal callbacks for different ways to reach secure
  *			world
- * @teedev:		client device
+ * @ctx:		driver internal TEE context
  * @smc:		specific to SMC ABI
  * @ffa:		specific to FF-A ABI
  * @call_queue:		queue of threads waiting to call @invoke_fn
@@ -152,6 +152,7 @@ struct optee {
 	struct tee_device *supp_teedev;
 	struct tee_device *teedev;
 	const struct optee_ops *ops;
+	struct tee_context *ctx;
 	union {
 		struct optee_smc smc;
 		struct optee_ffa ffa;