tee: optee: Fix supplicant based device enumeration

[ Upstream commit 7269cba53d906cf257c139d3b3a53ad272176bca ]

Currently supplicant dependent optee device enumeration only registers
devices whenever tee-supplicant is invoked for the first time. But it
forgets to remove devices when tee-supplicant daemon stops running and
closes its context gracefully. This leads to following error for fTPM
driver during reboot/shutdown:

[   73.466791] tpm tpm0: ftpm_tee_tpm_op_send: SUBMIT_COMMAND invoke error: 0xffff3024

Fix this by adding an attribute for supplicant dependent devices so that
the user-space service can detect and detach supplicant devices before
closing the supplicant:

$ for dev in /sys/bus/tee/devices/*; do if [[ -f "$dev/need_supplicant" && -f "$dev/driver/unbind" ]]; \
      then echo $(basename "$dev") > $dev/driver/unbind; fi done

Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Closes: https://github.com/OP-TEE/optee_os/issues/6094
Fixes: 5f178bb71e3a ("optee: enable support for multi-stage bus enumeration")
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Acked-by: Jerome Forissier <jerome.forissier@linaro.org>
[jw: fixed up Date documentation]
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/Documentation/ABI/testing/sysfs-bus-optee-devices b/Documentation/ABI/testing/sysfs-bus-optee-devices
index 0f58701..af31e5a 100644 (file)
--- a/Documentation/ABI/testing/sysfs-bus-optee-devices
+++ b/Documentation/ABI/testing/sysfs-bus-optee-devices
@@ -6,3 +6,12 @@ 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.
+
+What:          /sys/bus/tee/devices/optee-ta-<uuid>/need_supplicant
+Date:          November 2023
+KernelVersion: 6.7
+Contact:       op-tee@lists.trustedfirmware.org
+Description:
+               Allows to distinguish whether an OP-TEE based TA/device requires user-space
+               tee-supplicant to function properly or not. This attribute will be present for
+               devices which depend on tee-supplicant to be running.

diff --git a/drivers/tee/optee/device.c b/drivers/tee/optee/device.c
index 64f0e04..4b10921 100644 (file)
--- a/drivers/tee/optee/device.c
+++ b/drivers/tee/optee/device.c
@@ -60,7 +60,16 @@ static void optee_release_device(struct device *dev)
        kfree(optee_device);
 }
 
-static int optee_register_device(const uuid_t *device_uuid)
+static ssize_t need_supplicant_show(struct device *dev,
+                                   struct device_attribute *attr,
+                                   char *buf)
+{
+       return 0;
+}
+
+static DEVICE_ATTR_RO(need_supplicant);
+
+static int optee_register_device(const uuid_t *device_uuid, u32 func)
 {
        struct tee_client_device *optee_device = NULL;
        int rc;
@@ -83,6 +92,10 @@ static int optee_register_device(const uuid_t *device_uuid)
                put_device(&optee_device->dev);
        }
 
+       if (func == PTA_CMD_GET_DEVICES_SUPP)
+               device_create_file(&optee_device->dev,
+                                  &dev_attr_need_supplicant);
+
        return rc;
 }
 
@@ -142,7 +155,7 @@ static int __optee_enumerate_devices(u32 func)
        num_devices = shm_size / sizeof(uuid_t);
 
        for (idx = 0; idx < num_devices; idx++) {
-               rc = optee_register_device(&device_uuid[idx]);
+               rc = optee_register_device(&device_uuid[idx], func);
                if (rc)
                        goto out_shm;
        }