tee: optee: add shared buffer registration functions

This change adds ops for shm_(un)register functions in tee interface.
Client application can use these functions to (un)register an own shared
buffer in OP-TEE address space. This allows zero copy data sharing between
Normal and Secure Worlds.

Please note that while those functions were added to optee code,
it does not report to userspace that those functions are available.
OP-TEE code does not set TEE_GEN_CAP_REG_MEM flag. This flag will be
enabled only after all other features of dynamic shared memory will be
implemented in subsequent patches. Of course user can ignore presence of
TEE_GEN_CAP_REG_MEM flag and try do call those functions. This is okay,
driver will register shared buffer in OP-TEE, but any attempts to use
this shared buffer will fail.

Signed-off-by: Volodymyr Babchuk <vlad.babchuk@gmail.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

1 files changed, 69 insertions, 0 deletions

diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c
index e85860f6e057..a05e9e61105f 100644
--- a/drivers/tee/optee/call.c
+++ b/drivers/tee/optee/call.c
@@ -533,3 +533,72 @@ void optee_free_pages_list(void *list, size_t num_entries)
 	free_pages_exact(list, get_pages_list_size(num_entries));
 }
 
+int optee_shm_register(struct tee_context *ctx, struct tee_shm *shm,
+		       struct page **pages, size_t num_pages)
+{
+	struct tee_shm *shm_arg = NULL;
+	struct optee_msg_arg *msg_arg;
+	u64 *pages_list;
+	phys_addr_t msg_parg;
+	int rc = 0;
+
+	if (!num_pages)
+		return -EINVAL;
+
+	pages_list = optee_allocate_pages_list(num_pages);
+	if (!pages_list)
+		return -ENOMEM;
+
+	shm_arg = get_msg_arg(ctx, 1, &msg_arg, &msg_parg);
+	if (IS_ERR(shm_arg)) {
+		rc = PTR_ERR(shm_arg);
+		goto out;
+	}
+
+	optee_fill_pages_list(pages_list, pages, num_pages,
+			      tee_shm_get_page_offset(shm));
+
+	msg_arg->cmd = OPTEE_MSG_CMD_REGISTER_SHM;
+	msg_arg->params->attr = OPTEE_MSG_ATTR_TYPE_TMEM_OUTPUT |
+				OPTEE_MSG_ATTR_NONCONTIG;
+	msg_arg->params->u.tmem.shm_ref = (unsigned long)shm;
+	msg_arg->params->u.tmem.size = tee_shm_get_size(shm);
+	/*
+	 * In the least bits of msg_arg->params->u.tmem.buf_ptr we
+	 * store buffer offset from 4k page, as described in OP-TEE ABI.
+	 */
+	msg_arg->params->u.tmem.buf_ptr = virt_to_phys(pages_list) |
+	  (tee_shm_get_page_offset(shm) & (OPTEE_MSG_NONCONTIG_PAGE_SIZE - 1));
+
+	if (optee_do_call_with_arg(ctx, msg_parg) ||
+	    msg_arg->ret != TEEC_SUCCESS)
+		rc = -EINVAL;
+
+	tee_shm_free(shm_arg);
+out:
+	optee_free_pages_list(pages_list, num_pages);
+	return rc;
+}
+
+int optee_shm_unregister(struct tee_context *ctx, struct tee_shm *shm)
+{
+	struct tee_shm *shm_arg;
+	struct optee_msg_arg *msg_arg;
+	phys_addr_t msg_parg;
+	int rc = 0;
+
+	shm_arg = get_msg_arg(ctx, 1, &msg_arg, &msg_parg);
+	if (IS_ERR(shm_arg))
+		return PTR_ERR(shm_arg);
+
+	msg_arg->cmd = OPTEE_MSG_CMD_UNREGISTER_SHM;
+
+	msg_arg->params[0].attr = OPTEE_MSG_ATTR_TYPE_RMEM_INPUT;
+	msg_arg->params[0].u.rmem.shm_ref = (unsigned long)shm;
+
+	if (optee_do_call_with_arg(ctx, msg_parg) ||
+	    msg_arg->ret != TEEC_SUCCESS)
+		rc = -EINVAL;
+	tee_shm_free(shm_arg);
+	return rc;
+}