[PATCHv6 0/3] optee: register drivers on optee bus

[PATCHv6 0/3] optee: register drivers on optee bus

[Maxim Uvarov]

v6: - description, comments, patches reorder and destroy workqueue (Sumit Garg)
v5: - removed pr_err and fix typos in description (Jarkko Sakkinen)
    - added missed kfree in optee_open()
v4: - sysfs entry is optee-ta-uuid (Jerome Forissier, Sumit Garg)
    - added Documentation/ABI/testing/sysfs-bus-optee-devices (Greg Kroah-Hartman)
v3: - support tee-suppicant restart (Jens Wiklander)
    - description and comments (Jarkko Sakkinen)
    - do not name optee drivers by index in sysfs (Sumit Garg)
v2: - write TEE with capital letters.
    - declare __optee_enumerate_device() as static.

Maxim Uvarov (3):
  optee: use uuid for sysfs driver entry
  optee: enable support for multi-stage bus enumeration
  tpm_ftpm_tee: register driver on TEE bus

 .../ABI/testing/sysfs-bus-optee-devices       |  8 +++
 MAINTAINERS                                   |  1 +
 drivers/char/tpm/tpm_ftpm_tee.c               | 70 ++++++++++++++++---
 drivers/tee/optee/core.c                      | 27 ++++++-
 drivers/tee/optee/device.c                    | 35 ++++------
 drivers/tee/optee/optee_private.h             | 10 ++-
 6 files changed, 116 insertions(+), 35 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-optee-devices

-- 
2.17.1

[PATCHv6 1/3] optee: use uuid for sysfs driver entry

[Maxim Uvarov]

With the evolving use-cases for TEE bus, now it's required to support
multi-stage enumeration process. But using a simple index doesn't
suffice this requirement and instead leads to duplicate sysfs entries.
So instead switch to use more informative device UUID for sysfs entry
like:
/sys/bus/tee/devices/optee-ta-<uuid>

Signed-off-by: Maxim Uvarov <maxim.uvarov@linaro.org>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
---
 Documentation/ABI/testing/sysfs-bus-optee-devices | 8 ++++++++
 MAINTAINERS                                       | 1 +
 drivers/tee/optee/device.c                        | 6 +++---
 3 files changed, 12 insertions(+), 3 deletions(-)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-optee-devices

diff --git a/Documentation/ABI/testing/sysfs-bus-optee-devices b/Documentation/ABI/testing/sysfs-bus-optee-devices
new file mode 100644
index 000000000000..0ae04ae5374a
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-optee-devices
@@ -0,0 +1,8 @@
+What:		/sys/bus/tee/devices/optee-ta-<uuid>/
+Date:           May 2020
+KernelVersion   5.7
+Contact:        tee-dev@lists.linaro.org
+Description:
+		OP-TEE bus provides reference to registered drivers under this directory. The <uuid>
+		matches Trusted Application (TA) driver and corresponding TA in secure OS. Drivers
+		are free to create needed API under optee-ta-<uuid> directory.
diff --git a/MAINTAINERS b/MAINTAINERS
index ecc0749810b0..6717afef2de3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12516,6 +12516,7 @@ OP-TEE DRIVER
 M:	Jens Wiklander <jens.wiklander@linaro.org>
 L:	tee-dev@lists.linaro.org
 S:	Maintained
+F:	Documentation/ABI/testing/sysfs-bus-optee-devices
 F:	drivers/tee/optee/
 
 OP-TEE RANDOM NUMBER GENERATOR (RNG) DRIVER
diff --git a/drivers/tee/optee/device.c b/drivers/tee/optee/device.c
index e3a148521ec1..ed3d1ddfa52b 100644
--- a/drivers/tee/optee/device.c
+++ b/drivers/tee/optee/device.c
@@ -65,7 +65,7 @@ static int get_devices(struct tee_context *ctx, u32 session,
 	return 0;
 }
 
-static int optee_register_device(const uuid_t *device_uuid, u32 device_id)
+static int optee_register_device(const uuid_t *device_uuid)
 {
 	struct tee_client_device *optee_device = NULL;
 	int rc;
@@ -75,7 +75,7 @@ static int optee_register_device(const uuid_t *device_uuid, u32 device_id)
 		return -ENOMEM;
 
 	optee_device->dev.bus = &tee_bus_type;
-	dev_set_name(&optee_device->dev, "optee-clnt%u", device_id);
+	dev_set_name(&optee_device->dev, "optee-ta-%pUl", device_uuid);
 	uuid_copy(&optee_device->id.uuid, device_uuid);
 
 	rc = device_register(&optee_device->dev);
@@ -144,7 +144,7 @@ int optee_enumerate_devices(void)
 	num_devices = shm_size / sizeof(uuid_t);
 
 	for (idx = 0; idx < num_devices; idx++) {
-		rc = optee_register_device(&device_uuid[idx], idx);
+		rc = optee_register_device(&device_uuid[idx]);
 		if (rc)
 			goto out_shm;
 	}
-- 
2.17.1

[PATCHv6 2/3] optee: enable support for multi-stage bus enumeration

[Maxim Uvarov]

Some drivers (like ftpm) can operate only after tee-supplicant
runs because of tee-supplicant provides things like storage
services (rpmb, shm).  This patch splits probe of non tee-supplicant
dependable drivers to the early stage, and after tee-supplicant run
probe other drivers.

Signed-off-by: Maxim Uvarov <maxim.uvarov@linaro.org>
Suggested-by: Sumit Garg <sumit.garg@linaro.org>
Suggested-by: Arnd Bergmann <arnd@linaro.org>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
---
 drivers/tee/optee/core.c          | 27 ++++++++++++++++++++++++---
 drivers/tee/optee/device.c        | 29 +++++++++++------------------
 drivers/tee/optee/optee_private.h | 10 +++++++++-
 3 files changed, 44 insertions(+), 22 deletions(-)

diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
index 99698b8a3a74..b373b1b08b6d 100644
--- a/drivers/tee/optee/core.c
+++ b/drivers/tee/optee/core.c
@@ -17,6 +17,7 @@
 #include <linux/tee_drv.h>
 #include <linux/types.h>
 #include <linux/uaccess.h>
+#include <linux/workqueue.h>
 #include "optee_private.h"
 #include "optee_smc.h"
 #include "shm_pool.h"
@@ -218,6 +219,11 @@ static void optee_get_version(struct tee_device *teedev,
 	*vers = v;
 }
 
+static void optee_bus_scan(struct work_struct *work)
+{
+	WARN_ON(optee_enumerate_devices(PTA_CMD_GET_DEVICES_SUPP));
+}
+
 static int optee_open(struct tee_context *ctx)
 {
 	struct optee_context_data *ctxdata;
@@ -241,8 +247,18 @@ static int optee_open(struct tee_context *ctx)
 			kfree(ctxdata);
 			return -EBUSY;
 		}
-	}
 
+		if (!optee->scan_bus_done) {
+			INIT_WORK(&optee->scan_bus_work, optee_bus_scan);
+			optee->scan_bus_wq = create_workqueue("optee_bus_scan");
+			if (!optee->scan_bus_wq) {
+				kfree(ctxdata);
+				return -ECHILD;
+			}
+			queue_work(optee->scan_bus_wq, &optee->scan_bus_work);
+			optee->scan_bus_done = true;
+		}
+	}
 	mutex_init(&ctxdata->mutex);
 	INIT_LIST_HEAD(&ctxdata->sess_list);
 
@@ -296,8 +312,13 @@ static void optee_release(struct tee_context *ctx)
 
 	ctx->data = NULL;
 
-	if (teedev == optee->supp_teedev)
+	if (teedev == optee->supp_teedev) {
+		if (optee->scan_bus_wq) {
+			destroy_workqueue(optee->scan_bus_wq);
+			optee->scan_bus_wq = NULL;
+		}
 		optee_supp_release(&optee->supp);
+	}
 }
 
 static const struct tee_driver_ops optee_ops = {
@@ -675,7 +696,7 @@ static int optee_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, optee);
 
-	rc = optee_enumerate_devices();
+	rc = optee_enumerate_devices(PTA_CMD_GET_DEVICES);
 	if (rc) {
 		optee_remove(pdev);
 		return rc;
diff --git a/drivers/tee/optee/device.c b/drivers/tee/optee/device.c
index ed3d1ddfa52b..8cf96aaffecf 100644
--- a/drivers/tee/optee/device.c
+++ b/drivers/tee/optee/device.c
@@ -11,18 +11,6 @@
 #include <linux/uuid.h>
 #include "optee_private.h"
 
-/*
- * Get device UUIDs
- *
- * [out]     memref[0]        Array of device UUIDs
- *
- * Return codes:
- * TEE_SUCCESS - Invoke command success
- * TEE_ERROR_BAD_PARAMETERS - Incorrect input param
- * TEE_ERROR_SHORT_BUFFER - Output buffer size less than required
- */
-#define PTA_CMD_GET_DEVICES		0x0
-
 static int optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
 {
 	if (ver->impl_id == TEE_IMPL_ID_OPTEE)
@@ -32,7 +20,8 @@ static int optee_ctx_match(struct tee_ioctl_version_data *ver, const void *data)
 }
 
 static int get_devices(struct tee_context *ctx, u32 session,
-		       struct tee_shm *device_shm, u32 *shm_size)
+		       struct tee_shm *device_shm, u32 *shm_size,
+		       u32 func)
 {
 	int ret = 0;
 	struct tee_ioctl_invoke_arg inv_arg;
@@ -41,8 +30,7 @@ static int get_devices(struct tee_context *ctx, u32 session,
 	memset(&inv_arg, 0, sizeof(inv_arg));
 	memset(&param, 0, sizeof(param));
 
-	/* Invoke PTA_CMD_GET_DEVICES function */
-	inv_arg.func = PTA_CMD_GET_DEVICES;
+	inv_arg.func = func;
 	inv_arg.session = session;
 	inv_arg.num_params = 4;
 
@@ -87,7 +75,7 @@ static int optee_register_device(const uuid_t *device_uuid)
 	return rc;
 }
 
-int optee_enumerate_devices(void)
+static int __optee_enumerate_devices(u32 func)
 {
 	const uuid_t pta_uuid =
 		UUID_INIT(0x7011a688, 0xddde, 0x4053,
@@ -118,7 +106,7 @@ int optee_enumerate_devices(void)
 		goto out_ctx;
 	}
 
-	rc = get_devices(ctx, sess_arg.session, NULL, &shm_size);
+	rc = get_devices(ctx, sess_arg.session, NULL, &shm_size, func);
 	if (rc < 0 || !shm_size)
 		goto out_sess;
 
@@ -130,7 +118,7 @@ int optee_enumerate_devices(void)
 		goto out_sess;
 	}
 
-	rc = get_devices(ctx, sess_arg.session, device_shm, &shm_size);
+	rc = get_devices(ctx, sess_arg.session, device_shm, &shm_size, func);
 	if (rc < 0)
 		goto out_shm;
 
@@ -158,3 +146,8 @@ int optee_enumerate_devices(void)
 
 	return rc;
 }
+
+int optee_enumerate_devices(u32 func)
+{
+	return  __optee_enumerate_devices(func);
+}
diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
index d9c5037b4e03..8b71839a357e 100644
--- a/drivers/tee/optee/optee_private.h
+++ b/drivers/tee/optee/optee_private.h
@@ -78,6 +78,9 @@ struct optee_supp {
  * @memremaped_shm	virtual address of memory in shared memory pool
  * @sec_caps:		secure world capabilities defined by
  *			OPTEE_SMC_SEC_CAP_* in optee_smc.h
+ * @scan_bus_done	flag if device registation was already done.
+ * @scan_bus_wq		workqueue to scan optee bus and register optee drivers
+ * @scan_bus_work	workq to scan optee bus and register optee drivers
  */
 struct optee {
 	struct tee_device *supp_teedev;
@@ -89,6 +92,9 @@ struct optee {
 	struct tee_shm_pool *pool;
 	void *memremaped_shm;
 	u32 sec_caps;
+	bool   scan_bus_done;
+	struct workqueue_struct *scan_bus_wq;
+	struct work_struct scan_bus_work;
 };
 
 struct optee_session {
@@ -173,7 +179,9 @@ void optee_free_pages_list(void *array, size_t num_entries);
 void optee_fill_pages_list(u64 *dst, struct page **pages, int num_pages,
 			   size_t page_offset);
 
-int optee_enumerate_devices(void);
+#define PTA_CMD_GET_DEVICES		0x0
+#define PTA_CMD_GET_DEVICES_SUPP	0x1
+int optee_enumerate_devices(u32 func);
 
 /*
  * Small helpers
-- 
2.17.1

[PATCHv6 3/3] tpm_ftpm_tee: register driver on TEE bus

[Maxim Uvarov]

OP-TEE based fTPM Trusted Application depends on tee-supplicant to
provide NV RAM implementation based on RPMB secure storage. So this
dependency can be resolved via TEE bus where we only invoke fTPM
driver probe once fTPM device is registered on the bus which is only
true after the tee-supplicant is up and running. Additionally, TEE bus
provides auto device enumeration.

Signed-off-by: Maxim Uvarov <maxim.uvarov@linaro.org>
Suggested-by: Sumit Garg <sumit.garg@linaro.org>
Suggested-by: Arnd Bergmann <arnd@linaro.org>
Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
---
 drivers/char/tpm/tpm_ftpm_tee.c | 70 ++++++++++++++++++++++++++++-----
 1 file changed, 60 insertions(+), 10 deletions(-)

diff --git a/drivers/char/tpm/tpm_ftpm_tee.c b/drivers/char/tpm/tpm_ftpm_tee.c
index 22bf553ccf9d..28da638360d8 100644
--- a/drivers/char/tpm/tpm_ftpm_tee.c
+++ b/drivers/char/tpm/tpm_ftpm_tee.c
@@ -214,11 +214,10 @@ static int ftpm_tee_match(struct tee_ioctl_version_data *ver, const void *data)
  * Return:
  *	On success, 0. On failure, -errno.
  */
-static int ftpm_tee_probe(struct platform_device *pdev)
+static int ftpm_tee_probe(struct device *dev)
 {
 	int rc;
 	struct tpm_chip *chip;
-	struct device *dev = &pdev->dev;
 	struct ftpm_tee_private *pvt_data = NULL;
 	struct tee_ioctl_open_session_arg sess_arg;
 
@@ -297,6 +296,13 @@ static int ftpm_tee_probe(struct platform_device *pdev)
 	return rc;
 }
 
+static int ftpm_plat_tee_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+
+	return ftpm_tee_probe(dev);
+}
+
 /**
  * ftpm_tee_remove() - remove the TPM device
  * @pdev: the platform_device description.
@@ -304,9 +310,9 @@ static int ftpm_tee_probe(struct platform_device *pdev)
  * Return:
  *	0 always.
  */
-static int ftpm_tee_remove(struct platform_device *pdev)
+static int ftpm_tee_remove(struct device *dev)
 {
-	struct ftpm_tee_private *pvt_data = dev_get_drvdata(&pdev->dev);
+	struct ftpm_tee_private *pvt_data = dev_get_drvdata(dev);
 
 	/* Release the chip */
 	tpm_chip_unregister(pvt_data->chip);
@@ -328,11 +334,18 @@ static int ftpm_tee_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static int ftpm_plat_tee_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+
+	return ftpm_tee_remove(dev);
+}
+
 /**
  * ftpm_tee_shutdown() - shutdown the TPM device
  * @pdev: the platform_device description.
  */
-static void ftpm_tee_shutdown(struct platform_device *pdev)
+static void ftpm_plat_tee_shutdown(struct platform_device *pdev)
 {
 	struct ftpm_tee_private *pvt_data = dev_get_drvdata(&pdev->dev);
 
@@ -347,17 +360,54 @@ static const struct of_device_id of_ftpm_tee_ids[] = {
 };
 MODULE_DEVICE_TABLE(of, of_ftpm_tee_ids);
 
-static struct platform_driver ftpm_tee_driver = {
+static struct platform_driver ftpm_tee_plat_driver = {
 	.driver = {
 		.name = "ftpm-tee",
 		.of_match_table = of_match_ptr(of_ftpm_tee_ids),
 	},
-	.probe = ftpm_tee_probe,
-	.remove = ftpm_tee_remove,
-	.shutdown = ftpm_tee_shutdown,
+	.shutdown = ftpm_plat_tee_shutdown,
+	.probe = ftpm_plat_tee_probe,
+	.remove = ftpm_plat_tee_remove,
+};
+
+/* UUID of the fTPM TA */
+static const struct tee_client_device_id optee_ftpm_id_table[] = {
+	{UUID_INIT(0xbc50d971, 0xd4c9, 0x42c4,
+		   0x82, 0xcb, 0x34, 0x3f, 0xb7, 0xf3, 0x78, 0x96)},
+	{}
 };
 
-module_platform_driver(ftpm_tee_driver);
+MODULE_DEVICE_TABLE(tee, optee_ftpm_id_table);
+
+static struct tee_client_driver ftpm_tee_driver = {
+	.id_table	= optee_ftpm_id_table,
+	.driver		= {
+		.name		= "optee-ftpm",
+		.bus		= &tee_bus_type,
+		.probe		= ftpm_tee_probe,
+		.remove		= ftpm_tee_remove,
+	},
+};
+
+static int __init ftpm_mod_init(void)
+{
+	int rc;
+
+	rc = platform_driver_register(&ftpm_tee_plat_driver);
+	if (rc)
+		return rc;
+
+	return driver_register(&ftpm_tee_driver.driver);
+}
+
+static void __exit ftpm_mod_exit(void)
+{
+	platform_driver_unregister(&ftpm_tee_plat_driver);
+	driver_unregister(&ftpm_tee_driver.driver);
+}
+
+module_init(ftpm_mod_init);
+module_exit(ftpm_mod_exit);
 
 MODULE_AUTHOR("Thirupathaiah Annapureddy <thiruan@microsoft.com>");
 MODULE_DESCRIPTION("TPM Driver for fTPM TA in TEE");
-- 
2.17.1

Re: [PATCHv6 1/3] optee: use uuid for sysfs driver entry

[Jarkko Sakkinen]

On Mon, Jun 01, 2020 at 06:06:43PM +0300, Maxim Uvarov wrote:
> With the evolving use-cases for TEE bus, now it's required to support
> multi-stage enumeration process. But using a simple index doesn't
> suffice this requirement and instead leads to duplicate sysfs entries.
> So instead switch to use more informative device UUID for sysfs entry
> like:
> /sys/bus/tee/devices/optee-ta-<uuid>
> 
> Signed-off-by: Maxim Uvarov <maxim.uvarov@linaro.org>
> Reviewed-by: Sumit Garg <sumit.garg@linaro.org>

Why do you mean by duplicate sysfs entries?

> ---
>  Documentation/ABI/testing/sysfs-bus-optee-devices | 8 ++++++++
>  MAINTAINERS                                       | 1 +
>  drivers/tee/optee/device.c                        | 6 +++---
>  3 files changed, 12 insertions(+), 3 deletions(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-bus-optee-devices
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-optee-devices b/Documentation/ABI/testing/sysfs-bus-optee-devices
> new file mode 100644
> index 000000000000..0ae04ae5374a
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-optee-devices
> @@ -0,0 +1,8 @@
> +What:		/sys/bus/tee/devices/optee-ta-<uuid>/
> +Date:           May 2020
> +KernelVersion   5.7
> +Contact:        tee-dev@lists.linaro.org
> +Description:
> +		OP-TEE bus provides reference to registered drivers under this directory. The <uuid>
> +		matches Trusted Application (TA) driver and corresponding TA in secure OS. Drivers
> +		are free to create needed API under optee-ta-<uuid> directory.
> diff --git a/MAINTAINERS b/MAINTAINERS
> index ecc0749810b0..6717afef2de3 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -12516,6 +12516,7 @@ OP-TEE DRIVER
>  M:	Jens Wiklander <jens.wiklander@linaro.org>
>  L:	tee-dev@lists.linaro.org
>  S:	Maintained
> +F:	Documentation/ABI/testing/sysfs-bus-optee-devices
>  F:	drivers/tee/optee/
>  
>  OP-TEE RANDOM NUMBER GENERATOR (RNG) DRIVER
> diff --git a/drivers/tee/optee/device.c b/drivers/tee/optee/device.c
> index e3a148521ec1..ed3d1ddfa52b 100644
> --- a/drivers/tee/optee/device.c
> +++ b/drivers/tee/optee/device.c
> @@ -65,7 +65,7 @@ static int get_devices(struct tee_context *ctx, u32 session,
>  	return 0;
>  }
>  
> -static int optee_register_device(const uuid_t *device_uuid, u32 device_id)
> +static int optee_register_device(const uuid_t *device_uuid)
>  {
>  	struct tee_client_device *optee_device = NULL;
>  	int rc;
> @@ -75,7 +75,7 @@ static int optee_register_device(const uuid_t *device_uuid, u32 device_id)
>  		return -ENOMEM;
>  
>  	optee_device->dev.bus = &tee_bus_type;
> -	dev_set_name(&optee_device->dev, "optee-clnt%u", device_id);
> +	dev_set_name(&optee_device->dev, "optee-ta-%pUl", device_uuid);

This code is and already was broken. If dev_set_name() returns -ENOMEM,
the name will be a null pointer.

Also, I don't get how you can just swap the name without potentially
breaking the backwards compatiblity towards the user space.

/Jarkko

Re: [PATCHv6 1/3] optee: use uuid for sysfs driver entry

[Maxim Uvarov]

On Thu, 4 Jun 2020 at 11:37, Jarkko Sakkinen
<jarkko.sakkinen@linux.intel.com> wrote:
>
> On Mon, Jun 01, 2020 at 06:06:43PM +0300, Maxim Uvarov wrote:
> > With the evolving use-cases for TEE bus, now it's required to support
> > multi-stage enumeration process. But using a simple index doesn't
> > suffice this requirement and instead leads to duplicate sysfs entries.
> > So instead switch to use more informative device UUID for sysfs entry
> > like:
> > /sys/bus/tee/devices/optee-ta-<uuid>
> >
> > Signed-off-by: Maxim Uvarov <maxim.uvarov@linaro.org>
> > Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
>
> Why do you mean by duplicate sysfs entries?
>

Without this change it will try to register something like that:
first stage w/o tee-supplicant:
/sys/bus/tee/devices/optee-clnt0
/sys/bus/tee/devices/optee-clnt1
/sys/bus/tee/devices/optee-clnt3
Then with tee-supplicant also index started with 0. I.e.
/sys/bus/tee/devices/optee-clnt0
/sys/bus/tee/devices/optee-clnt1
...

So we need to increase global index or use some other unique names.



> > ---
> >  Documentation/ABI/testing/sysfs-bus-optee-devices | 8 ++++++++
> >  MAINTAINERS                                       | 1 +
> >  drivers/tee/optee/device.c                        | 6 +++---
> >  3 files changed, 12 insertions(+), 3 deletions(-)
> >  create mode 100644 Documentation/ABI/testing/sysfs-bus-optee-devices
> >
> > diff --git a/Documentation/ABI/testing/sysfs-bus-optee-devices b/Documentation/ABI/testing/sysfs-bus-optee-devices
> > new file mode 100644
> > index 000000000000..0ae04ae5374a
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-bus-optee-devices
> > @@ -0,0 +1,8 @@
> > +What:                /sys/bus/tee/devices/optee-ta-<uuid>/
> > +Date:           May 2020
> > +KernelVersion   5.7
> > +Contact:        tee-dev@lists.linaro.org
> > +Description:
> > +             OP-TEE bus provides reference to registered drivers under this directory. The <uuid>
> > +             matches Trusted Application (TA) driver and corresponding TA in secure OS. Drivers
> > +             are free to create needed API under optee-ta-<uuid> directory.
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index ecc0749810b0..6717afef2de3 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -12516,6 +12516,7 @@ OP-TEE DRIVER
> >  M:   Jens Wiklander <jens.wiklander@linaro.org>
> >  L:   tee-dev@lists.linaro.org
> >  S:   Maintained
> > +F:   Documentation/ABI/testing/sysfs-bus-optee-devices
> >  F:   drivers/tee/optee/
> >
> >  OP-TEE RANDOM NUMBER GENERATOR (RNG) DRIVER
> > diff --git a/drivers/tee/optee/device.c b/drivers/tee/optee/device.c
> > index e3a148521ec1..ed3d1ddfa52b 100644
> > --- a/drivers/tee/optee/device.c
> > +++ b/drivers/tee/optee/device.c
> > @@ -65,7 +65,7 @@ static int get_devices(struct tee_context *ctx, u32 session,
> >       return 0;
> >  }
> >
> > -static int optee_register_device(const uuid_t *device_uuid, u32 device_id)
> > +static int optee_register_device(const uuid_t *device_uuid)
> >  {
> >       struct tee_client_device *optee_device = NULL;
> >       int rc;
> > @@ -75,7 +75,7 @@ static int optee_register_device(const uuid_t *device_uuid, u32 device_id)
> >               return -ENOMEM;
> >
> >       optee_device->dev.bus = &tee_bus_type;
> > -     dev_set_name(&optee_device->dev, "optee-clnt%u", device_id);
> > +     dev_set_name(&optee_device->dev, "optee-ta-%pUl", device_uuid);
>
> This code is and already was broken. If dev_set_name() returns -ENOMEM,
> the name will be a null pointer.
>

Well in the current code base only 1% of drivers check the return code
of dev_set_name(). But I don't  mind adding this check.


> Also, I don't get how you can just swap the name without potentially
> breaking the backwards compatiblity towards the user space.
>
> /Jarkko

Backwards compatibility to what? API (stable, testing) are defined in
Documentation. There was no doc for that. And user get notifications
on uevent, so it's udev deal how to find proper sysfs entry.

Regards,
Maxim.

Re: [PATCHv6 1/3] optee: use uuid for sysfs driver entry

[Sumit Garg]

On Thu, 4 Jun 2020 at 14:07, Jarkko Sakkinen
<jarkko.sakkinen@linux.intel.com> wrote:
>
> On Mon, Jun 01, 2020 at 06:06:43PM +0300, Maxim Uvarov wrote:
> > With the evolving use-cases for TEE bus, now it's required to support
> > multi-stage enumeration process. But using a simple index doesn't
> > suffice this requirement and instead leads to duplicate sysfs entries.
> > So instead switch to use more informative device UUID for sysfs entry
> > like:
> > /sys/bus/tee/devices/optee-ta-<uuid>
> >
> > Signed-off-by: Maxim Uvarov <maxim.uvarov@linaro.org>
> > Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
>
> Why do you mean by duplicate sysfs entries?
>

It's just about the device being added with the same name as of the
device which is already present on the TEE bus. So this leads to
duplicate sysfs entry error for device node which is created during
device_register() execution flow.

> > ---
> >  Documentation/ABI/testing/sysfs-bus-optee-devices | 8 ++++++++
> >  MAINTAINERS                                       | 1 +
> >  drivers/tee/optee/device.c                        | 6 +++---
> >  3 files changed, 12 insertions(+), 3 deletions(-)
> >  create mode 100644 Documentation/ABI/testing/sysfs-bus-optee-devices
> >
> > diff --git a/Documentation/ABI/testing/sysfs-bus-optee-devices b/Documentation/ABI/testing/sysfs-bus-optee-devices
> > new file mode 100644
> > index 000000000000..0ae04ae5374a
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-bus-optee-devices
> > @@ -0,0 +1,8 @@
> > +What:                /sys/bus/tee/devices/optee-ta-<uuid>/
> > +Date:           May 2020
> > +KernelVersion   5.7
> > +Contact:        tee-dev@lists.linaro.org
> > +Description:
> > +             OP-TEE bus provides reference to registered drivers under this directory. The <uuid>
> > +             matches Trusted Application (TA) driver and corresponding TA in secure OS. Drivers
> > +             are free to create needed API under optee-ta-<uuid> directory.
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index ecc0749810b0..6717afef2de3 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -12516,6 +12516,7 @@ OP-TEE DRIVER
> >  M:   Jens Wiklander <jens.wiklander@linaro.org>
> >  L:   tee-dev@lists.linaro.org
> >  S:   Maintained
> > +F:   Documentation/ABI/testing/sysfs-bus-optee-devices
> >  F:   drivers/tee/optee/
> >
> >  OP-TEE RANDOM NUMBER GENERATOR (RNG) DRIVER
> > diff --git a/drivers/tee/optee/device.c b/drivers/tee/optee/device.c
> > index e3a148521ec1..ed3d1ddfa52b 100644
> > --- a/drivers/tee/optee/device.c
> > +++ b/drivers/tee/optee/device.c
> > @@ -65,7 +65,7 @@ static int get_devices(struct tee_context *ctx, u32 session,
> >       return 0;
> >  }
> >
> > -static int optee_register_device(const uuid_t *device_uuid, u32 device_id)
> > +static int optee_register_device(const uuid_t *device_uuid)
> >  {
> >       struct tee_client_device *optee_device = NULL;
> >       int rc;
> > @@ -75,7 +75,7 @@ static int optee_register_device(const uuid_t *device_uuid, u32 device_id)
> >               return -ENOMEM;
> >
> >       optee_device->dev.bus = &tee_bus_type;
> > -     dev_set_name(&optee_device->dev, "optee-clnt%u", device_id);
> > +     dev_set_name(&optee_device->dev, "optee-ta-%pUl", device_uuid);
>
> This code is and already was broken. If dev_set_name() returns -ENOMEM,
> the name will be a null pointer.

Is this an expected error scenario? dev_set_name() is invoked at
numerous places in the kernel without any error check.

>
> Also, I don't get how you can just swap the name without potentially
> breaking the backwards compatiblity towards the user space.

As of now, there isn't any compatibility concerns with user space as
these TEE devices are meant to be used by kernel drivers only. TEE
user-space interface is quite separate (see: Documentation/tee.txt).

-Sumit

>
> /Jarkko

Re: [PATCHv6 1/3] optee: use uuid for sysfs driver entry

[Jarkko Sakkinen]

On Thu, Jun 04, 2020 at 12:16:21PM +0300, Maxim Uvarov wrote:
> On Thu, 4 Jun 2020 at 11:37, Jarkko Sakkinen
> <jarkko.sakkinen@linux.intel.com> wrote:
> >
> > On Mon, Jun 01, 2020 at 06:06:43PM +0300, Maxim Uvarov wrote:
> > > With the evolving use-cases for TEE bus, now it's required to support
> > > multi-stage enumeration process. But using a simple index doesn't
> > > suffice this requirement and instead leads to duplicate sysfs entries.
> > > So instead switch to use more informative device UUID for sysfs entry
> > > like:
> > > /sys/bus/tee/devices/optee-ta-<uuid>
> > >
> > > Signed-off-by: Maxim Uvarov <maxim.uvarov@linaro.org>
> > > Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
> >
> > Why do you mean by duplicate sysfs entries?
> >
> 
> Without this change it will try to register something like that:
> first stage w/o tee-supplicant:
> /sys/bus/tee/devices/optee-clnt0
> /sys/bus/tee/devices/optee-clnt1
> /sys/bus/tee/devices/optee-clnt3
> Then with tee-supplicant also index started with 0. I.e.
> /sys/bus/tee/devices/optee-clnt0
> /sys/bus/tee/devices/optee-clnt1
> ...
> 
> So we need to increase global index or use some other unique names.

Got it, thanks.

/Jarkko

Re: [PATCHv6 1/3] optee: use uuid for sysfs driver entry

[Jarkko Sakkinen]

On Thu, Jun 04, 2020 at 02:51:03PM +0530, Sumit Garg wrote:
> On Thu, 4 Jun 2020 at 14:07, Jarkko Sakkinen
> <jarkko.sakkinen@linux.intel.com> wrote:
> >
> > On Mon, Jun 01, 2020 at 06:06:43PM +0300, Maxim Uvarov wrote:
> > > With the evolving use-cases for TEE bus, now it's required to support
> > > multi-stage enumeration process. But using a simple index doesn't
> > > suffice this requirement and instead leads to duplicate sysfs entries.
> > > So instead switch to use more informative device UUID for sysfs entry
> > > like:
> > > /sys/bus/tee/devices/optee-ta-<uuid>
> > >
> > > Signed-off-by: Maxim Uvarov <maxim.uvarov@linaro.org>
> > > Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
> >
> > Why do you mean by duplicate sysfs entries?
> >
> 
> It's just about the device being added with the same name as of the
> device which is already present on the TEE bus. So this leads to
> duplicate sysfs entry error for device node which is created during
> device_register() execution flow.
> 
> > > ---
> > >  Documentation/ABI/testing/sysfs-bus-optee-devices | 8 ++++++++
> > >  MAINTAINERS                                       | 1 +
> > >  drivers/tee/optee/device.c                        | 6 +++---
> > >  3 files changed, 12 insertions(+), 3 deletions(-)
> > >  create mode 100644 Documentation/ABI/testing/sysfs-bus-optee-devices
> > >
> > > diff --git a/Documentation/ABI/testing/sysfs-bus-optee-devices b/Documentation/ABI/testing/sysfs-bus-optee-devices
> > > new file mode 100644
> > > index 000000000000..0ae04ae5374a
> > > --- /dev/null
> > > +++ b/Documentation/ABI/testing/sysfs-bus-optee-devices
> > > @@ -0,0 +1,8 @@
> > > +What:                /sys/bus/tee/devices/optee-ta-<uuid>/
> > > +Date:           May 2020
> > > +KernelVersion   5.7
> > > +Contact:        tee-dev@lists.linaro.org
> > > +Description:
> > > +             OP-TEE bus provides reference to registered drivers under this directory. The <uuid>
> > > +             matches Trusted Application (TA) driver and corresponding TA in secure OS. Drivers
> > > +             are free to create needed API under optee-ta-<uuid> directory.
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index ecc0749810b0..6717afef2de3 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -12516,6 +12516,7 @@ OP-TEE DRIVER
> > >  M:   Jens Wiklander <jens.wiklander@linaro.org>
> > >  L:   tee-dev@lists.linaro.org
> > >  S:   Maintained
> > > +F:   Documentation/ABI/testing/sysfs-bus-optee-devices
> > >  F:   drivers/tee/optee/
> > >
> > >  OP-TEE RANDOM NUMBER GENERATOR (RNG) DRIVER
> > > diff --git a/drivers/tee/optee/device.c b/drivers/tee/optee/device.c
> > > index e3a148521ec1..ed3d1ddfa52b 100644
> > > --- a/drivers/tee/optee/device.c
> > > +++ b/drivers/tee/optee/device.c
> > > @@ -65,7 +65,7 @@ static int get_devices(struct tee_context *ctx, u32 session,
> > >       return 0;
> > >  }
> > >
> > > -static int optee_register_device(const uuid_t *device_uuid, u32 device_id)
> > > +static int optee_register_device(const uuid_t *device_uuid)
> > >  {
> > >       struct tee_client_device *optee_device = NULL;
> > >       int rc;
> > > @@ -75,7 +75,7 @@ static int optee_register_device(const uuid_t *device_uuid, u32 device_id)
> > >               return -ENOMEM;
> > >
> > >       optee_device->dev.bus = &tee_bus_type;
> > > -     dev_set_name(&optee_device->dev, "optee-clnt%u", device_id);
> > > +     dev_set_name(&optee_device->dev, "optee-ta-%pUl", device_uuid);
> >
> > This code is and already was broken. If dev_set_name() returns -ENOMEM,
> > the name will be a null pointer.
> 
> Is this an expected error scenario? dev_set_name() is invoked at
> numerous places in the kernel without any error check.
> 
> >
> > Also, I don't get how you can just swap the name without potentially
> > breaking the backwards compatiblity towards the user space.
> 
> As of now, there isn't any compatibility concerns with user space as
> these TEE devices are meant to be used by kernel drivers only. TEE
> user-space interface is quite separate (see: Documentation/tee.txt).

OK, probably would make sense to have this in the commit message as a
remark.

/Jarkko