1 files changed, 273 insertions, 0 deletions
diff --git a/drivers/tee/optee/supp.c b/drivers/tee/optee/supp.c
new file mode 100644
index 000000000000..b4ea0678a436
--- /dev/null
+++ b/drivers/tee/optee/supp.c
@@ -0,0 +1,273 @@
+/*
+ * Copyright (c) 2015, Linaro Limited
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include "optee_private.h"
+
+void optee_supp_init(struct optee_supp *supp)
+{
+	memset(supp, 0, sizeof(*supp));
+	mutex_init(&supp->ctx_mutex);
+	mutex_init(&supp->thrd_mutex);
+	mutex_init(&supp->supp_mutex);
+	init_completion(&supp->data_to_supp);
+	init_completion(&supp->data_from_supp);
+}
+
+void optee_supp_uninit(struct optee_supp *supp)
+{
+	mutex_destroy(&supp->ctx_mutex);
+	mutex_destroy(&supp->thrd_mutex);
+	mutex_destroy(&supp->supp_mutex);
+}
+
+/**
+ * optee_supp_thrd_req() - request service from supplicant
+ * @ctx:	context doing the request
+ * @func:	function requested
+ * @num_params:	number of elements in @param array
+ * @param:	parameters for function
+ *
+ * Returns result of operation to be passed to secure world
+ */
+u32 optee_supp_thrd_req(struct tee_context *ctx, u32 func, size_t num_params,
+			struct tee_param *param)
+{
+	bool interruptable;
+	struct optee *optee = tee_get_drvdata(ctx->teedev);
+	struct optee_supp *supp = &optee->supp;
+	u32 ret;
+
+	/*
+	 * Other threads blocks here until we've copied our answer from
+	 * supplicant.
+	 */
+	while (mutex_lock_interruptible(&supp->thrd_mutex)) {
+		/* See comment below on when the RPC can be interrupted. */
+		mutex_lock(&supp->ctx_mutex);
+		interruptable = !supp->ctx;
+		mutex_unlock(&supp->ctx_mutex);
+		if (interruptable)
+			return TEEC_ERROR_COMMUNICATION;
+	}
+
+	/*
+	 * We have exclusive access now since the supplicant at this
+	 * point is either doing a
+	 * wait_for_completion_interruptible(&supp->data_to_supp) or is in
+	 * userspace still about to do the ioctl() to enter
+	 * optee_supp_recv() below.
+	 */
+
+	supp->func = func;
+	supp->num_params = num_params;
+	supp->param = param;
+	supp->req_posted = true;
+
+	/* Let supplicant get the data */
+	complete(&supp->data_to_supp);
+
+	/*
+	 * Wait for supplicant to process and return result, once we've
+	 * returned from wait_for_completion(data_from_supp) we have
+	 * exclusive access again.
+	 */
+	while (wait_for_completion_interruptible(&supp->data_from_supp)) {
+		mutex_lock(&supp->ctx_mutex);
+		interruptable = !supp->ctx;
+		if (interruptable) {
+			/*
+			 * There's no supplicant available and since the
+			 * supp->ctx_mutex currently is held none can
+			 * become available until the mutex released
+			 * again.
+			 *
+			 * Interrupting an RPC to supplicant is only
+			 * allowed as a way of slightly improving the user
+			 * experience in case the supplicant hasn't been
+			 * started yet. During normal operation the supplicant
+			 * will serve all requests in a timely manner and
+			 * interrupting then wouldn't make sense.
+			 */
+			supp->ret = TEEC_ERROR_COMMUNICATION;
+			init_completion(&supp->data_to_supp);
+		}
+		mutex_unlock(&supp->ctx_mutex);
+		if (interruptable)
+			break;
+	}
+
+	ret = supp->ret;
+	supp->param = NULL;
+	supp->req_posted = false;
+
+	/* We're done, let someone else talk to the supplicant now. */
+	mutex_unlock(&supp->thrd_mutex);
+
+	return ret;
+}
+
+/**
+ * optee_supp_recv() - receive request for supplicant
+ * @ctx:	context receiving the request
+ * @func:	requested function in supplicant
+ * @num_params:	number of elements allocated in @param, updated with number
+ *		used elements
+ * @param:	space for parameters for @func
+ *
+ * Returns 0 on success or <0 on failure
+ */
+int optee_supp_recv(struct tee_context *ctx, u32 *func, u32 *num_params,
+		    struct tee_param *param)
+{
+	struct tee_device *teedev = ctx->teedev;
+	struct optee *optee = tee_get_drvdata(teedev);
+	struct optee_supp *supp = &optee->supp;
+	int rc;
+
+	/*
+	 * In case two threads in one supplicant is calling this function
+	 * simultaneously we need to protect the data with a mutex which
+	 * we'll release before returning.
+	 */
+	mutex_lock(&supp->supp_mutex);
+
+	if (supp->supp_next_send) {
+		/*
+		 * optee_supp_recv() has been called again without
+		 * a optee_supp_send() in between. Supplicant has
+		 * probably been restarted before it was able to
+		 * write back last result. Abort last request and
+		 * wait for a new.
+		 */
+		if (supp->req_posted) {
+			supp->ret = TEEC_ERROR_COMMUNICATION;
+			supp->supp_next_send = false;
+			complete(&supp->data_from_supp);
+		}
+	}
+
+	/*
+	 * This is where supplicant will be hanging most of the
+	 * time, let's make this interruptable so we can easily
+	 * restart supplicant if needed.
+	 */
+	if (wait_for_completion_interruptible(&supp->data_to_supp)) {
+		rc = -ERESTARTSYS;
+		goto out;
+	}
+
+	/* We have exlusive access to the data */
+
+	if (*num_params < supp->num_params) {
+		/*
+		 * Not enough room for parameters, tell supplicant
+		 * it failed and abort last request.
+		 */
+		supp->ret = TEEC_ERROR_COMMUNICATION;
+		rc = -EINVAL;
+		complete(&supp->data_from_supp);
+		goto out;
+	}
+
+	*func = supp->func;
+	*num_params = supp->num_params;
+	memcpy(param, supp->param,
+	       sizeof(struct tee_param) * supp->num_params);
+
+	/* Allow optee_supp_send() below to do its work */
+	supp->supp_next_send = true;
+
+	rc = 0;
+out:
+	mutex_unlock(&supp->supp_mutex);
+	return rc;
+}
+
+/**
+ * optee_supp_send() - send result of request from supplicant
+ * @ctx:	context sending result
+ * @ret:	return value of request
+ * @num_params:	number of parameters returned
+ * @param:	returned parameters
+ *
+ * Returns 0 on success or <0 on failure.
+ */
+int optee_supp_send(struct tee_context *ctx, u32 ret, u32 num_params,
+		    struct tee_param *param)
+{
+	struct tee_device *teedev = ctx->teedev;
+	struct optee *optee = tee_get_drvdata(teedev);
+	struct optee_supp *supp = &optee->supp;
+	size_t n;
+	int rc = 0;
+
+	/*
+	 * We still have exclusive access to the data since that's how we
+	 * left it when returning from optee_supp_read().
+	 */
+
+	/* See comment on mutex in optee_supp_read() above */
+	mutex_lock(&supp->supp_mutex);
+
+	if (!supp->supp_next_send) {
+		/*
+		 * Something strange is going on, supplicant shouldn't
+		 * enter optee_supp_send() in this state
+		 */
+		rc = -ENOENT;
+		goto out;
+	}
+
+	if (num_params != supp->num_params) {
+		/*
+		 * Something is wrong, let supplicant restart. Next call to
+		 * optee_supp_recv() will give an error to the requesting
+		 * thread and release it.
+		 */
+		rc = -EINVAL;
+		goto out;
+	}
+
+	/* Update out and in/out parameters */
+	for (n = 0; n < num_params; n++) {
+		struct tee_param *p = supp->param + n;
+
+		switch (p->attr) {
+		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT:
+			p->u.value.a = param[n].u.value.a;
+			p->u.value.b = param[n].u.value.b;
+			p->u.value.c = param[n].u.value.c;
+			break;
+		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
+		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
+			p->u.memref.size = param[n].u.memref.size;
+			break;
+		default:
+			break;
+		}
+	}
+	supp->ret = ret;
+
+	/* Allow optee_supp_recv() above to do its work */
+	supp->supp_next_send = false;
+
+	/* Let the requesting thread continue */
+	complete(&supp->data_from_supp);
+out:
+	mutex_unlock(&supp->supp_mutex);
+	return rc;
+}