[PATCH v2 0/2] OP-TEE FF-A notifications

[PATCH v2 0/2] OP-TEE FF-A notifications

[Jens Wiklander]

Hi all,

This patchset adds support for using FF-A notifications as a delivery
mechanism of asynchronous notifications from OP-TEE running in the secure
world. Support for asynchronous notifications via the SMC ABI was added in
[1], here we add the counterpart needed when using the the FF-A ABI.

Support for FF-A notifications is added with [2] and this patch set is based
on Sudeeps tree at [3].

[1] https://lore.kernel.org/lkml/20211103090255.998070-1-jens.wiklander@linaro.org/
[2] https://lore.kernel.org/linux-arm-kernel/20231005-ffa_v1-1_notif-v4-0-cddd3237809c@arm.com/
[3] https://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux.git/tag/?h=ffa-updates-6.7
    commit bcefd1bf63b1 ("firmware: arm_ffa: Upgrade the driver version to v1.1")

v1->v2:
* Applied Sumit's Reviewed-by
* Addressed Sumit's comment on "optee: ffa_abi: add asynchronous
  notifications"

Thanks,
Jens

Jens Wiklander (2):
  optee: provide optee_do_bottom_half() as a common function
  optee: ffa_abi: add asynchronous notifications

 drivers/tee/optee/call.c          | 31 ++++++++++-
 drivers/tee/optee/ffa_abi.c       | 93 ++++++++++++++++++++++++++++++-
 drivers/tee/optee/optee_ffa.h     | 28 ++++++++--
 drivers/tee/optee/optee_private.h |  9 ++-
 drivers/tee/optee/smc_abi.c       | 36 ++----------
 5 files changed, 155 insertions(+), 42 deletions(-)


base-commit: bcefd1bf63b1ec9bb08067021cf47f0fad96f395
-- 
2.34.1

[PATCH v2 1/2] optee: provide optee_do_bottom_half() as a common function

[Jens Wiklander]

Provides optee_do_bottom_half() and optee_stop_async_notif() as common
functions callable from the FF-A ABI part of the driver too.

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
---
 drivers/tee/optee/call.c          | 31 +++++++++++++++++++++++++-
 drivers/tee/optee/optee_private.h |  5 ++++-
 drivers/tee/optee/smc_abi.c       | 36 ++++---------------------------
 3 files changed, 38 insertions(+), 34 deletions(-)

diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c
index df5fb5410b72..5afc759794ce 100644
--- a/drivers/tee/optee/call.c
+++ b/drivers/tee/optee/call.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * Copyright (c) 2015-2021, Linaro Limited
+ * Copyright (c) 2015-2021, 2023 Linaro Limited
  */
 #include <linux/device.h>
 #include <linux/err.h>
@@ -524,3 +524,32 @@ int optee_check_mem_type(unsigned long start, size_t num_pages)
 
 	return rc;
 }
+
+static int simple_call_with_arg(struct tee_context *ctx, u32 cmd)
+{
+	struct optee *optee = tee_get_drvdata(ctx->teedev);
+	struct optee_shm_arg_entry *entry;
+	struct optee_msg_arg *msg_arg;
+	struct tee_shm *shm;
+	u_int offs;
+
+	msg_arg = optee_get_msg_arg(ctx, 0, &entry, &shm, &offs);
+	if (IS_ERR(msg_arg))
+		return PTR_ERR(msg_arg);
+
+	msg_arg->cmd = cmd;
+	optee->ops->do_call_with_arg(ctx, shm, offs);
+
+	optee_free_msg_arg(ctx, entry, offs);
+	return 0;
+}
+
+int optee_do_bottom_half(struct tee_context *ctx)
+{
+	return simple_call_with_arg(ctx, OPTEE_MSG_CMD_DO_BOTTOM_HALF);
+}
+
+int optee_stop_async_notif(struct tee_context *ctx)
+{
+	return simple_call_with_arg(ctx, OPTEE_MSG_CMD_STOP_ASYNC_NOTIF);
+}
diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
index 72685ee0d53f..2165bd11e6ac 100644
--- a/drivers/tee/optee/optee_private.h
+++ b/drivers/tee/optee/optee_private.h
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 /*
- * Copyright (c) 2015-2021, Linaro Limited
+ * Copyright (c) 2015-2021, 2023 Linaro Limited
  */
 
 #ifndef OPTEE_PRIVATE_H
@@ -325,6 +325,9 @@ void optee_rpc_cmd_free_suppl(struct tee_context *ctx, struct tee_shm *shm);
 void optee_rpc_cmd(struct tee_context *ctx, struct optee *optee,
 		   struct optee_msg_arg *arg);
 
+int optee_do_bottom_half(struct tee_context *ctx);
+int optee_stop_async_notif(struct tee_context *ctx);
+
 /*
  * Small helpers
  */
diff --git a/drivers/tee/optee/smc_abi.c b/drivers/tee/optee/smc_abi.c
index d5b28fd35d66..94e96803a722 100644
--- a/drivers/tee/optee/smc_abi.c
+++ b/drivers/tee/optee/smc_abi.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * Copyright (c) 2015-2021, Linaro Limited
+ * Copyright (c) 2015-2021, 2023 Linaro Limited
  * Copyright (c) 2016, EPAM Systems
  */
 
@@ -965,34 +965,6 @@ static int optee_smc_do_call_with_arg(struct tee_context *ctx,
 	return rc;
 }
 
-static int simple_call_with_arg(struct tee_context *ctx, u32 cmd)
-{
-	struct optee_shm_arg_entry *entry;
-	struct optee_msg_arg *msg_arg;
-	struct tee_shm *shm;
-	u_int offs;
-
-	msg_arg = optee_get_msg_arg(ctx, 0, &entry, &shm, &offs);
-	if (IS_ERR(msg_arg))
-		return PTR_ERR(msg_arg);
-
-	msg_arg->cmd = cmd;
-	optee_smc_do_call_with_arg(ctx, shm, offs);
-
-	optee_free_msg_arg(ctx, entry, offs);
-	return 0;
-}
-
-static int optee_smc_do_bottom_half(struct tee_context *ctx)
-{
-	return simple_call_with_arg(ctx, OPTEE_MSG_CMD_DO_BOTTOM_HALF);
-}
-
-static int optee_smc_stop_async_notif(struct tee_context *ctx)
-{
-	return simple_call_with_arg(ctx, OPTEE_MSG_CMD_STOP_ASYNC_NOTIF);
-}
-
 /*
  * 5. Asynchronous notification
  */
@@ -1048,7 +1020,7 @@ static irqreturn_t notif_irq_thread_fn(int irq, void *dev_id)
 {
 	struct optee *optee = dev_id;
 
-	optee_smc_do_bottom_half(optee->ctx);
+	optee_do_bottom_half(optee->ctx);
 
 	return IRQ_HANDLED;
 }
@@ -1086,7 +1058,7 @@ static void notif_pcpu_irq_work_fn(struct work_struct *work)
 						   notif_pcpu_work);
 	struct optee *optee = container_of(optee_smc, struct optee, smc);
 
-	optee_smc_do_bottom_half(optee->ctx);
+	optee_do_bottom_half(optee->ctx);
 }
 
 static int init_pcpu_irq(struct optee *optee, u_int irq)
@@ -1158,7 +1130,7 @@ static void uninit_pcpu_irq(struct optee *optee)
 static void optee_smc_notif_uninit_irq(struct optee *optee)
 {
 	if (optee->smc.sec_caps & OPTEE_SMC_SEC_CAP_ASYNC_NOTIF) {
-		optee_smc_stop_async_notif(optee->ctx);
+		optee_stop_async_notif(optee->ctx);
 		if (optee->smc.notif_irq) {
 			if (irq_is_percpu_devid(optee->smc.notif_irq))
 				uninit_pcpu_irq(optee);
-- 
2.34.1

[PATCH v2 2/2] optee: ffa_abi: add asynchronous notifications

[Jens Wiklander]

Adds support for asynchronous notifications from OP-TEE in secure world
when communicating via FF-A. In principle from OP-TEE and kernel driver
point of view this works in the same way as for the SMC ABI based
implementation.

The OP-TEE FF-A ABI is expanded in OPTEE_FFA_EXCHANGE_CAPABILITIES with
the capability OPTEE_FFA_SEC_CAP_ASYNC_NOTIF to indicate that OP-TEE
supports asynchronous notifications. OPTEE_FFA_ENABLE_ASYNC_NOTIF is
also added to tell that the driver has successfully initialized these
notifications.

Notification capability is negotiated while the driver is initialized.
If both sides supports these notifications then they are enabled.

The notification concept in this driver is merged with the FF-A concept,
the lower 64 values are reserved for FF-A as asynchronous notifications
while the synchronous notifications use the higher values.

So a FF-A notification has to be allocated for each discrete
asynchronous notification value needed. Only one asynchronous
notification value is used at the moment, the "do bottom half"
notification.

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
---
 drivers/tee/optee/ffa_abi.c       | 93 ++++++++++++++++++++++++++++++-
 drivers/tee/optee/optee_ffa.h     | 28 ++++++++--
 drivers/tee/optee/optee_private.h |  4 +-
 3 files changed, 117 insertions(+), 8 deletions(-)

diff --git a/drivers/tee/optee/ffa_abi.c b/drivers/tee/optee/ffa_abi.c
index 0828240f27e6..60823b41b9ad 100644
--- a/drivers/tee/optee/ffa_abi.c
+++ b/drivers/tee/optee/ffa_abi.c
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * Copyright (c) 2021, Linaro Limited
+ * Copyright (c) 2021, 2023 Linaro Limited
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -692,7 +692,8 @@ static bool optee_ffa_api_is_compatbile(struct ffa_device *ffa_dev,
 static bool optee_ffa_exchange_caps(struct ffa_device *ffa_dev,
 				    const struct ffa_ops *ops,
 				    u32 *sec_caps,
-				    unsigned int *rpc_param_count)
+				    unsigned int *rpc_param_count,
+				    unsigned int *max_notif_value)
 {
 	struct ffa_send_direct_data data = { OPTEE_FFA_EXCHANGE_CAPABILITIES };
 	int rc;
@@ -709,10 +710,39 @@ static bool optee_ffa_exchange_caps(struct ffa_device *ffa_dev,
 
 	*rpc_param_count = (u8)data.data1;
 	*sec_caps = data.data2;
+	if (data.data3)
+		*max_notif_value = data.data3;
+	else
+		*max_notif_value = OPTEE_DEFAULT_MAX_NOTIF_VALUE;
 
 	return true;
 }
 
+static void notif_callback(int notify_id, void *cb_data)
+{
+	struct optee *optee = cb_data;
+
+	if (notify_id == optee->ffa.bottom_half_value)
+		optee_do_bottom_half(optee->ctx);
+	else
+		optee_notif_send(optee, notify_id);
+}
+
+static int enable_async_notif(struct optee *optee)
+{
+	struct ffa_device *ffa_dev = optee->ffa.ffa_dev;
+	struct ffa_send_direct_data data = {
+		.data0 = OPTEE_FFA_ENABLE_ASYNC_NOTIF,
+		.data1 = optee->ffa.bottom_half_value,
+	};
+	int rc;
+
+	rc = ffa_dev->ops->msg_ops->sync_send_receive(ffa_dev, &data);
+	if (rc)
+		return rc;
+	return data.data0;
+}
+
 static void optee_ffa_get_version(struct tee_device *teedev,
 				  struct tee_ioctl_version_data *vers)
 {
@@ -775,7 +805,11 @@ static const struct optee_ops optee_ffa_ops = {
 static void optee_ffa_remove(struct ffa_device *ffa_dev)
 {
 	struct optee *optee = ffa_dev_get_drvdata(ffa_dev);
+	u32 bottom_half_id = optee->ffa.bottom_half_value;
 
+	if (bottom_half_id != U32_MAX)
+		ffa_dev->ops->notifier_ops->notify_relinquish(ffa_dev,
+							      bottom_half_id);
 	optee_remove_common(optee);
 
 	mutex_destroy(&optee->ffa.mutex);
@@ -784,9 +818,51 @@ static void optee_ffa_remove(struct ffa_device *ffa_dev)
 	kfree(optee);
 }
 
+static int optee_ffa_async_notif_init(struct ffa_device *ffa_dev,
+				      struct optee *optee)
+{
+	bool is_per_vcpu = false;
+	u32 notif_id = 0;
+	int rc;
+
+	while (true) {
+		rc = ffa_dev->ops->notifier_ops->notify_request(ffa_dev,
+								is_per_vcpu,
+								notif_callback,
+								optee,
+								notif_id);
+		if (!rc)
+			break;
+		/*
+		 * -EACCES means that the notification ID was
+		 * already bound, try the next one as long as we
+		 * haven't reached the max. Any other error is a
+		 * permanent error, so skip asynchronous
+		 * notifications in that case.
+		 */
+		if (rc != -EACCES)
+			return rc;
+		notif_id++;
+		if (notif_id >= OPTEE_FFA_MAX_ASYNC_NOTIF_VALUE)
+			return rc;
+	}
+	optee->ffa.bottom_half_value = notif_id;
+
+	rc = enable_async_notif(optee);
+	if (rc < 0) {
+		ffa_dev->ops->notifier_ops->notify_relinquish(ffa_dev,
+							      notif_id);
+		optee->ffa.bottom_half_value = U32_MAX;
+	}
+
+	return rc;
+}
+
 static int optee_ffa_probe(struct ffa_device *ffa_dev)
 {
+	const struct ffa_notifier_ops *notif_ops;
 	const struct ffa_ops *ffa_ops;
+	unsigned int max_notif_value;
 	unsigned int rpc_param_count;
 	struct tee_shm_pool *pool;
 	struct tee_device *teedev;
@@ -797,12 +873,13 @@ static int optee_ffa_probe(struct ffa_device *ffa_dev)
 	int rc;
 
 	ffa_ops = ffa_dev->ops;
+	notif_ops = ffa_ops->notifier_ops;
 
 	if (!optee_ffa_api_is_compatbile(ffa_dev, ffa_ops))
 		return -EINVAL;
 
 	if (!optee_ffa_exchange_caps(ffa_dev, ffa_ops, &sec_caps,
-				     &rpc_param_count))
+				     &rpc_param_count, &max_notif_value))
 		return -EINVAL;
 	if (sec_caps & OPTEE_FFA_SEC_CAP_ARG_OFFSET)
 		arg_cache_flags |= OPTEE_SHM_ARG_SHARED;
@@ -820,6 +897,7 @@ static int optee_ffa_probe(struct ffa_device *ffa_dev)
 
 	optee->ops = &optee_ffa_ops;
 	optee->ffa.ffa_dev = ffa_dev;
+	optee->ffa.bottom_half_value = U32_MAX;
 	optee->rpc_param_count = rpc_param_count;
 
 	teedev = tee_device_alloc(&optee_ffa_clnt_desc, NULL, optee->pool,
@@ -864,6 +942,12 @@ static int optee_ffa_probe(struct ffa_device *ffa_dev)
 	rc = optee_notif_init(optee, OPTEE_DEFAULT_MAX_NOTIF_VALUE);
 	if (rc)
 		goto err_close_ctx;
+	if (sec_caps & OPTEE_FFA_SEC_CAP_ASYNC_NOTIF) {
+		rc = optee_ffa_async_notif_init(ffa_dev, optee);
+		if (rc < 0)
+			pr_err("Failed to initialize async notifications: %d",
+			       rc);
+	}
 
 	rc = optee_enumerate_devices(PTA_CMD_GET_DEVICES);
 	if (rc)
@@ -874,6 +958,9 @@ static int optee_ffa_probe(struct ffa_device *ffa_dev)
 
 err_unregister_devices:
 	optee_unregister_devices();
+	if (optee->ffa.bottom_half_value != U32_MAX)
+		notif_ops->notify_relinquish(ffa_dev,
+					     optee->ffa.bottom_half_value);
 	optee_notif_uninit(optee);
 err_close_ctx:
 	teedev_close_context(ctx);
diff --git a/drivers/tee/optee/optee_ffa.h b/drivers/tee/optee/optee_ffa.h
index 97266243deaa..5db779dc00de 100644
--- a/drivers/tee/optee/optee_ffa.h
+++ b/drivers/tee/optee/optee_ffa.h
@@ -1,6 +1,6 @@
 /* SPDX-License-Identifier: BSD-2-Clause */
 /*
- * Copyright (c) 2019-2021, Linaro Limited
+ * Copyright (c) 2019-2021, 2023 Linaro Limited
  */
 
 /*
@@ -73,7 +73,7 @@
  *
  * Call register usage:
  * w3:    Service ID, OPTEE_FFA_EXCHANGE_CAPABILITIES
- * w4-w7: Note used (MBZ)
+ * w4-w7: Not used (MBZ)
  *
  * Return register usage:
  * w3:    Error code, 0 on success
@@ -82,14 +82,16 @@
  *                   OPTEE_FFA_YIELDING_CALL_WITH_ARG.
  *        Bit[31:8]: Reserved (MBZ)
  * w5:	  Bitfield of secure world capabilities OPTEE_FFA_SEC_CAP_* below,
- *	  unused bits MBZ.
- * w6-w7: Not used (MBZ)
+ * w6:	  The maximum secure world notification number
+ * w7:	  Not used (MBZ)
  */
 /*
  * Secure world supports giving an offset into the argument shared memory
  * object, see also OPTEE_FFA_YIELDING_CALL_WITH_ARG
  */
 #define OPTEE_FFA_SEC_CAP_ARG_OFFSET	BIT(0)
+/* OP-TEE supports asynchronous notification via FF-A */
+#define OPTEE_FFA_SEC_CAP_ASYNC_NOTIF	BIT(1)
 
 #define OPTEE_FFA_EXCHANGE_CAPABILITIES OPTEE_FFA_BLOCKING_CALL(2)
 
@@ -108,6 +110,24 @@
  */
 #define OPTEE_FFA_UNREGISTER_SHM	OPTEE_FFA_BLOCKING_CALL(3)
 
+/*
+ * Inform OP-TEE that the normal world is able to receive asynchronous
+ * notifications.
+ *
+ * Call register usage:
+ * w3:    Service ID, OPTEE_FFA_ENABLE_ASYNC_NOTIF
+ * w4:	  Notification value to request bottom half processing, should be
+ *	  less than OPTEE_FFA_MAX_ASYNC_NOTIF_VALUE.
+ * w5-w7: Not used (MBZ)
+ *
+ * Return register usage:
+ * w3:    Error code, 0 on success
+ * w4-w7: Note used (MBZ)
+ */
+#define OPTEE_FFA_ENABLE_ASYNC_NOTIF	OPTEE_FFA_BLOCKING_CALL(5)
+
+#define OPTEE_FFA_MAX_ASYNC_NOTIF_VALUE 64
+
 /*
  * Call with struct optee_msg_arg as argument in the supplied shared memory
  * with a zero internal offset and normal cached memory attributes.
diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
index 2165bd11e6ac..91f4ec45e388 100644
--- a/drivers/tee/optee/optee_private.h
+++ b/drivers/tee/optee/optee_private.h
@@ -129,12 +129,14 @@ struct optee_smc {
  * struct optee_ffa_data -  FFA communication struct
  * @ffa_dev		FFA device, contains the destination id, the id of
  *			OP-TEE in secure world
- * @ffa_ops		FFA operations
+ * @bottom_half_value	Notification ID used for bottom half signalling or
+ *			U32_MAX if unused
  * @mutex		Serializes access to @global_ids
  * @global_ids		FF-A shared memory global handle translation
  */
 struct optee_ffa {
 	struct ffa_device *ffa_dev;
+	u32 bottom_half_value;
 	/* Serializes access to @global_ids */
 	struct mutex mutex;
 	struct rhashtable global_ids;
-- 
2.34.1

Re: [PATCH v2 0/2] OP-TEE FF-A notifications

[Jens Wiklander]

On Tue, Nov 7, 2023 at 5:07 PM Jens Wiklander <jens.wiklander@linaro.org> wrote:
>
> Hi all,
>
> This patchset adds support for using FF-A notifications as a delivery
> mechanism of asynchronous notifications from OP-TEE running in the secure
> world. Support for asynchronous notifications via the SMC ABI was added in
> [1], here we add the counterpart needed when using the the FF-A ABI.
>
> Support for FF-A notifications is added with [2] and this patch set is based
> on Sudeeps tree at [3].
>
> [1] https://lore.kernel.org/lkml/20211103090255.998070-1-jens.wiklander@linaro.org/
> [2] https://lore.kernel.org/linux-arm-kernel/20231005-ffa_v1-1_notif-v4-0-cddd3237809c@arm.com/
> [3] https://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux.git/tag/?h=ffa-updates-6.7
>     commit bcefd1bf63b1 ("firmware: arm_ffa: Upgrade the driver version to v1.1")
>
> v1->v2:
> * Applied Sumit's Reviewed-by
> * Addressed Sumit's comment on "optee: ffa_abi: add asynchronous
>   notifications"
>
> Thanks,
> Jens
>
> Jens Wiklander (2):
>   optee: provide optee_do_bottom_half() as a common function
>   optee: ffa_abi: add asynchronous notifications
>
>  drivers/tee/optee/call.c          | 31 ++++++++++-
>  drivers/tee/optee/ffa_abi.c       | 93 ++++++++++++++++++++++++++++++-
>  drivers/tee/optee/optee_ffa.h     | 28 ++++++++--
>  drivers/tee/optee/optee_private.h |  9 ++-
>  drivers/tee/optee/smc_abi.c       | 36 ++----------
>  5 files changed, 155 insertions(+), 42 deletions(-)
>
>
> base-commit: bcefd1bf63b1ec9bb08067021cf47f0fad96f395
> --
> 2.34.1
>

I'm picking up this.

Thanks,
Jens