[PATCH v2 1/1] tee: add cancellation support to client interface

[Igor Opaniuk <igor.opaniuk@linaro.org>]

Add support of cancellation request to the TEE kernel internal
client interface. Can be used by software TPM drivers, that leverage
TEE under the hood (for instance TPM2.0 mobile profile), for requesting
cancellation of time-consuming operations (RSA key-pair generation etc.).

Signed-off-by: Igor Opaniuk <igor.opaniuk@linaro.org>
---

v2:
- use tee_ioctl_cancel_arg to provide session and cancel_id
- fix tee_client_cancel_req function description header

 drivers/tee/tee_core.c  | 10 ++++++++++
 include/linux/tee_drv.h | 12 ++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
index 7b2bb4c..1148175 100644
--- a/drivers/tee/tee_core.c
+++ b/drivers/tee/tee_core.c
@@ -1027,6 +1027,16 @@ int tee_client_invoke_func(struct tee_context *ctx,
 }
 EXPORT_SYMBOL_GPL(tee_client_invoke_func);
 
+int tee_client_cancel_req(struct tee_context *ctx,
+			  struct tee_ioctl_cancel_arg *arg)
+{
+	if (!ctx->teedev->desc->ops->cancel_req)
+		return -EINVAL;
+	return ctx->teedev->desc->ops->cancel_req(ctx, arg->cancel_id,
+						  arg->session);
+}
+EXPORT_SYMBOL_GPL(tee_client_cancel_req);
+
 static int __init tee_init(void)
 {
 	int rc;
diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
index 6cfe058..177016e 100644
--- a/include/linux/tee_drv.h
+++ b/include/linux/tee_drv.h
@@ -526,6 +526,18 @@ int tee_client_invoke_func(struct tee_context *ctx,
 			   struct tee_ioctl_invoke_arg *arg,
 			   struct tee_param *param);
 
+/**
+ * tee_client_cancel_req() - Request cancellation of the previous open-session
+ * or invoke-command operations in a Trusted Application
+ * @ctx:       TEE Context
+ * @arg:       Cancellation arguments, see description of
+ *             struct tee_ioctl_cancel_arg
+ *
+ * Returns < 0 on error else 0 if the cancellation was successfully requested.
+ */
+int tee_client_cancel_req(struct tee_context *ctx,
+			  struct tee_ioctl_cancel_arg *arg);
+
 static inline bool tee_param_is_memref(struct tee_param *param)
 {
 	switch (param->attr & TEE_IOCTL_PARAM_ATTR_TYPE_MASK) {
-- 
2.7.4