Linux Kernel: TEE

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// include/linux/tee_core.h

/**
 * struct tee_device - TEE Device representation
 * @name:	name of device
 * @desc:	description of device
 * @id:		unique id of device
 * @flags:	represented by TEE_DEVICE_FLAG_REGISTERED above
 * @dev:	embedded basic device structure
 * @cdev:	embedded cdev
 * @num_users:	number of active users of this device
 * @c_no_user:	completion used when unregistering the device
 * @mutex:	mutex protecting @num_users and @idr
 * @idr:	register of user space shared memory objects allocated or
 *		registered on this device
 * @pool:	shared memory pool
 */
struct tee_device {
	char name[TEE_MAX_DEV_NAME_LEN];
	const struct tee_desc *desc;
	int id;
	unsigned int flags;

	struct device dev;
	struct cdev cdev;

	size_t num_users;
	struct completion c_no_users;
	struct mutex mutex;	/* protects num_users and idr */

	struct idr idr;
	struct tee_shm_pool *pool;
};

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// include/linux/tee_core.h

/**
 * struct tee_desc - Describes the TEE driver to the subsystem
 * @name:	name of driver
 * @ops:	driver operations vtable
 * @owner:	module providing the driver
 * @flags:	Extra properties of driver, defined by TEE_DESC_* below
 */
#define TEE_DESC_PRIVILEGED	0x1
struct tee_desc {
	const char *name;
	const struct tee_driver_ops *ops;
	struct module *owner;
	u32 flags;
};

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// include/linux/tee_core.h

/**
 * struct tee_driver_ops - driver operations vtable
 * @get_version:	returns version of driver
 * @open:		called when the device file is opened
 * @release:		release this open file
 * @open_session:	open a new session
 * @close_session:	close a session
 * @system_session:	declare session as a system session
 * @invoke_func:	invoke a trusted function
 * @cancel_req:		request cancel of an ongoing invoke or open
 * @supp_recv:		called for supplicant to get a command
 * @supp_send:		called for supplicant to send a response
 * @shm_register:	register shared memory buffer in TEE
 * @shm_unregister:	unregister shared memory buffer in TEE
 */
struct tee_driver_ops {
	void (*get_version)(struct tee_device *teedev,
			    struct tee_ioctl_version_data *vers);
	int (*open)(struct tee_context *ctx);
	void (*release)(struct tee_context *ctx);
	int (*open_session)(struct tee_context *ctx,
			    struct tee_ioctl_open_session_arg *arg,
			    struct tee_param *param);
	int (*close_session)(struct tee_context *ctx, u32 session);
	int (*system_session)(struct tee_context *ctx, u32 session);
	int (*invoke_func)(struct tee_context *ctx,
			   struct tee_ioctl_invoke_arg *arg,
			   struct tee_param *param);
	int (*cancel_req)(struct tee_context *ctx, u32 cancel_id, u32 session);
	int (*supp_recv)(struct tee_context *ctx, u32 *func, u32 *num_params,
			 struct tee_param *param);
	int (*supp_send)(struct tee_context *ctx, u32 ret, u32 num_params,
			 struct tee_param *param);
	int (*shm_register)(struct tee_context *ctx, struct tee_shm *shm,
			    struct page **pages, size_t num_pages,
			    unsigned long start);
	int (*shm_unregister)(struct tee_context *ctx, struct tee_shm *shm);
};

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// include/linux/tee_core.h

/**
 * struct tee_shm_pool - shared memory pool
 * @ops:		operations
 * @private_data:	private data for the shared memory manager
 */
struct tee_shm_pool {
	const struct tee_shm_pool_ops *ops;
	void *private_data;
};

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// include/linux/tee_core.h

/**
 * struct tee_shm_pool_ops - shared memory pool operations
 * @alloc:		called when allocating shared memory
 * @free:		called when freeing shared memory
 * @destroy_pool:	called when destroying the pool
 */
struct tee_shm_pool_ops {
	int (*alloc)(struct tee_shm_pool *pool, struct tee_shm *shm,
		     size_t size, size_t align);
	void (*free)(struct tee_shm_pool *pool, struct tee_shm *shm);
	void (*destroy_pool)(struct tee_shm_pool *pool);
};

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// include/linux/tee_drv.h

/**
 * struct tee_context - driver specific context on file pointer data
 * @teedev:	pointer to this drivers struct tee_device
 * @data:	driver specific context data, managed by the driver
 * @refcount:	reference counter for this structure
 * @releasing:  flag that indicates if context is being released right now.
 *		It is needed to break circular dependency on context during
 *              shared memory release.
 * @supp_nowait: flag that indicates that requests in this context should not
 *              wait for tee-supplicant daemon to be started if not present
 *              and just return with an error code. It is needed for requests
 *              that arises from TEE based kernel drivers that should be
 *              non-blocking in nature.
 * @cap_memref_null: flag indicating if the TEE Client support shared
 *                   memory buffer with a NULL pointer.
 */
struct tee_context {
	struct tee_device *teedev;
	void *data;
	struct kref refcount;
	bool releasing;
	bool supp_nowait;
	bool cap_memref_null;
};