linux-kernel - Re: [PATCH v4 1/2] tee: optee: Fix supplicant based device enumeration

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Date:   Fri, 3 Nov 2023 09:34:55 +0100
From:   Jens Wiklander <jens.wiklander@...aro.org>
To:     Sumit Garg <sumit.garg@...aro.org>
Cc:     Ilias Apalodimas <ilias.apalodimas@...aro.org>,
        op-tee@...ts.trustedfirmware.org, jan.kiszka@...mens.com,
        arnd@...aro.org, ardb@...nel.org, jerome.forissier@...aro.org,
        masahisa.kojima@...aro.org, maxim.uvarov@...aro.org,
        jarkko.sakkinen@...ux.intel.com, linux-kernel@...r.kernel.org,
        diogo.ivo@...mens.com
Subject: Re: [PATCH v4 1/2] tee: optee: Fix supplicant based device enumeration

Hi,

On Fri, Nov 3, 2023 at 6:52 AM Sumit Garg <sumit.garg@...aro.org> wrote:
>
> Hi Ilias,
>
> On Thu, 2 Nov 2023 at 19:58, Ilias Apalodimas
> <ilias.apalodimas@...aro.org> wrote:
> >
> > Hi Sumit,
> >
> > On Thu, 2 Nov 2023 at 09:31, Sumit Garg <sumit.garg@...aro.org> wrote:
> > >
> > > 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@...mens.com>
> > > Link: https://github.com/OP-TEE/optee_os/issues/6094

Checkpatch complains here, we should use "Closes:" instead of "Link:".

> > > Fixes: 5f178bb71e3a ("optee: enable support for multi-stage bus enumeration")
> > > Signed-off-by: Sumit Garg <sumit.garg@...aro.org>
> > > ---
> > >  .../ABI/testing/sysfs-bus-optee-devices         |  9 +++++++++
> > >  drivers/tee/optee/device.c                      | 17 +++++++++++++++--
> > >  2 files changed, 24 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/Documentation/ABI/testing/sysfs-bus-optee-devices b/Documentation/ABI/testing/sysfs-bus-optee-devices
> > > index 0f58701367b6..d914f6629662 100644
> > > --- 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:          July 2008
> >
> > nit, date needs changing
> >
>
> Thanks for catching that. If nothing major comes up then I hope Jens
> can correct it while applying.

Sure, I can update it to November 2023.

I'll fix the date and the "Closes:" tag if there's no v5.

Cheers,
Jens

>
> > > +KernelVersion: 6.7
> > > +Contact:       op-tee@...ts.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 64f0e047c23d..4b1092127694 100644
> > > --- 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
> >
> > (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;
> > >         }
> > > --
> > > 2.34.1
> > >
> >
> > Other than that
> > Reviewed-by: Ilias Apalodimas <ilias.apalodimas@...aro.org>
>
> Thanks.
>
> -Sumit