[PATCH backport 5.10] optee: use driver internal tee_context for some rpc

* [PATCH backport 5.10] optee: use driver internal tee_context for some rpc
@ 2022-02-18 13:15 Jens Wiklander
  2022-02-20 11:36 ` Greg KH
  0 siblings, 1 reply; 2+ messages in thread
From: Jens Wiklander @ 2022-02-18 13:15 UTC (permalink / raw)
  To: stable; +Cc: Sumit Garg, Jens Wiklander, Lars Persson

commit aceeafefff736057e8f93f19bbfbef26abd94604 upstream

Adds a driver private tee_context to struct optee.

The new driver internal tee_context is used 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 # 1e2c3ef0496e tee: export teedev_open() and teedev_close_context()
Cc: stable@vger.kernel.org
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
[JW: backport to 5.10-stable + update commit message]
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
---
 drivers/tee/optee/core.c          | 8 ++++++++
 drivers/tee/optee/optee_private.h | 2 ++
 drivers/tee/optee/rpc.c           | 8 +++++---
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
index f255a96ae5a4..b99ee487f56d 100644
--- a/drivers/tee/optee/core.c
+++ b/drivers/tee/optee/core.c
@@ -588,6 +588,7 @@ static int optee_remove(struct platform_device *pdev)
 	/* Unregister OP-TEE specific client devices on TEE bus */
 	optee_unregister_devices();
 
+	teedev_close_context(optee->ctx);
 	/*
 	 * Ask OP-TEE to free all cached shared memory objects to decrease
 	 * reference counters and also avoid wild pointers in secure world
@@ -633,6 +634,7 @@ static int optee_probe(struct platform_device *pdev)
 	struct optee *optee = NULL;
 	void *memremaped_shm = NULL;
 	struct tee_device *teedev;
+	struct tee_context *ctx;
 	u32 sec_caps;
 	int rc;
 
@@ -719,6 +721,12 @@ static int optee_probe(struct platform_device *pdev)
 	optee_supp_init(&optee->supp);
 	optee->memremaped_shm = memremaped_shm;
 	optee->pool = pool;
+	ctx = teedev_open(optee->teedev);
+	if (IS_ERR(ctx)) {
+		rc = rc = PTR_ERR(ctx);
+		goto err;
+	}
+	optee->ctx = ctx;
 
 	/*
 	 * Ensure that there are no pre-existing shm objects before enabling
diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
index f6bb4a763ba9..ea09533e30cd 100644
--- a/drivers/tee/optee/optee_private.h
+++ b/drivers/tee/optee/optee_private.h
@@ -70,6 +70,7 @@ struct optee_supp {
  * struct optee - main service struct
  * @supp_teedev:	supplicant device
  * @teedev:		client device
+ * @ctx:		driver internal TEE context
  * @invoke_fn:		function to issue smc or hvc
  * @call_queue:		queue of threads waiting to call @invoke_fn
  * @wait_queue:		queue of threads from secure world waiting for a
@@ -87,6 +88,7 @@ struct optee {
 	struct tee_device *supp_teedev;
 	struct tee_device *teedev;
 	optee_invoke_fn *invoke_fn;
+	struct tee_context *ctx;
 	struct optee_call_queue call_queue;
 	struct optee_wait_queue wait_queue;
 	struct optee_supp supp;
diff --git a/drivers/tee/optee/rpc.c b/drivers/tee/optee/rpc.c
index 9dbdd783d6f2..f1e0332b0f6e 100644
--- a/drivers/tee/optee/rpc.c
+++ b/drivers/tee/optee/rpc.c
@@ -284,6 +284,7 @@ static struct tee_shm *cmd_alloc_suppl(struct tee_context *ctx, size_t sz)
 }
 
 static void handle_rpc_func_cmd_shm_alloc(struct tee_context *ctx,
+					  struct optee *optee,
 					  struct optee_msg_arg *arg,
 					  struct optee_call_ctx *call_ctx)
 {
@@ -313,7 +314,8 @@ static void handle_rpc_func_cmd_shm_alloc(struct tee_context *ctx,
 		shm = cmd_alloc_suppl(ctx, sz);
 		break;
 	case OPTEE_MSG_RPC_SHM_TYPE_KERNEL:
-		shm = tee_shm_alloc(ctx, sz, TEE_SHM_MAPPED | TEE_SHM_PRIV);
+		shm = tee_shm_alloc(optee->ctx, sz,
+				    TEE_SHM_MAPPED | TEE_SHM_PRIV);
 		break;
 	default:
 		arg->ret = TEEC_ERROR_BAD_PARAMETERS;
@@ -470,7 +472,7 @@ static void handle_rpc_func_cmd(struct tee_context *ctx, struct optee *optee,
 		break;
 	case OPTEE_MSG_RPC_CMD_SHM_ALLOC:
 		free_pages_list(call_ctx);
-		handle_rpc_func_cmd_shm_alloc(ctx, arg, call_ctx);
+		handle_rpc_func_cmd_shm_alloc(ctx, optee, arg, call_ctx);
 		break;
 	case OPTEE_MSG_RPC_CMD_SHM_FREE:
 		handle_rpc_func_cmd_shm_free(ctx, arg);
@@ -501,7 +503,7 @@ void optee_handle_rpc(struct tee_context *ctx, struct optee_rpc_param *param,
 
 	switch (OPTEE_SMC_RETURN_GET_RPC_FUNC(param->a0)) {
 	case OPTEE_SMC_RPC_FUNC_ALLOC:
-		shm = tee_shm_alloc(ctx, param->a1,
+		shm = tee_shm_alloc(optee->ctx, param->a1,
 				    TEE_SHM_MAPPED | TEE_SHM_PRIV);
 		if (!IS_ERR(shm) && !tee_shm_get_pa(shm, 0, &pa)) {
 			reg_pair_from_64(&param->a1, &param->a2, pa);
-- 
2.31.1


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