Re: [PATCH v2 1/1] tee: optee: expose OS revision via sysfs

[Sumit Garg via OP-TEE <op-tee@lists.trustedfirmware.org>]

On Mon, Nov 24, 2025 at 08:15:04AM +0100, Jens Wiklander wrote:
> Hi,
> 
> On Sat, Nov 22, 2025 at 4:00 PM Wei Ming Chen <jj251510319013@gmail.com> wrote:
> >
> > From: Aristo Chen <aristo.chen@canonical.com>
> >
> > Today the only way to read the OP-TEE OS version is from dmesg/journal
> > logs, which can be lost as buffers roll over. Capture the OS revision
> > (major/minor/build_id) from secure world for both SMC and FF-A ABIs, store
> > it in the OP-TEE driver, and expose a stable userspace readout via
> > /sys/class/tee/tee*/optee_os_revision.
> >
> > Signed-off-by: Aristo Chen <aristo.chen@canonical.com>
> > ---
> >  drivers/tee/optee/core.c          | 19 +++++++++++++++++++
> >  drivers/tee/optee/ffa_abi.c       | 13 +++++++++++--
> >  drivers/tee/optee/optee_private.h | 17 +++++++++++++++++
> >  drivers/tee/optee/smc_abi.c       | 13 +++++++++++--
> >  4 files changed, 58 insertions(+), 4 deletions(-)
> 
> This appears to be a feature that could be useful for all TEEs.

True, it is something that TEE core should support. Although I would
have preferred to extend TEE_IOC_VERSION since that's the common way the
user-space library get's TEE implementation specific information. But
since it being already a user-space ABI which doesn't offer extension.
Maybe we can consider adding TEE_IOC_REVERSION instead of sysfs.

But before doing that we need to know who is the actual consumer here
from user-space perspective? Will the client applications also depend on
the TEE implementation revision?

> If so,
> let's take a step back to see what's needed. We can add the sysfs
> attribute from drivers/tee/tee_core.c and add another optional
> callback to struct tee_driver_ops, such as get_tee_revision(). For
> OP-TEE, the specific information we want to share is clear, but other
> TEEs might have additional or different data. What do others think?

Implementation wise, this sounds like a reasonable approach.

-Sumit

> 
> Cheers,
> Jens
> 
> >
> > diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
> > index 5b62139714ce..66409cf5da1c 100644
> > --- a/drivers/tee/optee/core.c
> > +++ b/drivers/tee/optee/core.c
> > @@ -83,8 +83,27 @@ static ssize_t rpmb_routing_model_show(struct device *dev,
> >  }
> >  static DEVICE_ATTR_RO(rpmb_routing_model);
> >
> > +static ssize_t optee_os_revision_show(struct device *dev,
> > +                                     struct device_attribute *attr, char *buf)
> > +{
> > +       struct optee *optee = dev_get_drvdata(dev);
> > +       struct optee_version_info *v;
> > +
> > +       if (!optee)
> > +               return -ENODEV;
> > +
> > +       v = &optee->version_info;
> > +       if (v->os_build_id)
> > +               return sysfs_emit(buf, "%u.%u (%016llx)\n", v->os_major,
> > +                                 v->os_minor, (unsigned long long)v->os_build_id);
> > +
> > +       return sysfs_emit(buf, "%u.%u\n", v->os_major, v->os_minor);
> > +}
> > +static DEVICE_ATTR_RO(optee_os_revision);
> > +
> >  static struct attribute *optee_dev_attrs[] = {
> >         &dev_attr_rpmb_routing_model.attr,
> > +       &dev_attr_optee_os_revision.attr,
> >         NULL
> >  };
> >
> > diff --git a/drivers/tee/optee/ffa_abi.c b/drivers/tee/optee/ffa_abi.c
> > index bf8390789ecf..3d4f35599dd1 100644
> > --- a/drivers/tee/optee/ffa_abi.c
> > +++ b/drivers/tee/optee/ffa_abi.c
> > @@ -776,7 +776,8 @@ static int optee_ffa_reclaim_protmem(struct optee *optee,
> >   */
> >
> >  static bool optee_ffa_api_is_compatible(struct ffa_device *ffa_dev,
> > -                                       const struct ffa_ops *ops)
> > +                                       const struct ffa_ops *ops,
> > +                                       struct optee_version_info *version_info)
> >  {
> >         const struct ffa_msg_ops *msg_ops = ops->msg_ops;
> >         struct ffa_send_direct_data data = {
> > @@ -806,6 +807,12 @@ static bool optee_ffa_api_is_compatible(struct ffa_device *ffa_dev,
> >                 pr_err("Unexpected error %d\n", rc);
> >                 return false;
> >         }
> > +       if (version_info) {
> > +               version_info->os_major = data.data0;
> > +               version_info->os_minor = data.data1;
> > +               version_info->os_build_id = data.data2;
> > +       }
> > +
> >         if (data.data2)
> >                 pr_info("revision %lu.%lu (%08lx)",
> >                         data.data0, data.data1, data.data2);
> > @@ -1034,6 +1041,7 @@ static int optee_ffa_probe(struct ffa_device *ffa_dev)
> >  {
> >         const struct ffa_notifier_ops *notif_ops;
> >         const struct ffa_ops *ffa_ops;
> > +       struct optee_version_info version_info = { };
> >         unsigned int max_notif_value;
> >         unsigned int rpc_param_count;
> >         struct tee_shm_pool *pool;
> > @@ -1047,7 +1055,7 @@ static int optee_ffa_probe(struct ffa_device *ffa_dev)
> >         ffa_ops = ffa_dev->ops;
> >         notif_ops = ffa_ops->notifier_ops;
> >
> > -       if (!optee_ffa_api_is_compatible(ffa_dev, ffa_ops))
> > +       if (!optee_ffa_api_is_compatible(ffa_dev, ffa_ops, &version_info))
> >                 return -EINVAL;
> >
> >         if (!optee_ffa_exchange_caps(ffa_dev, ffa_ops, &sec_caps,
> > @@ -1059,6 +1067,7 @@ static int optee_ffa_probe(struct ffa_device *ffa_dev)
> >         optee = kzalloc(sizeof(*optee), GFP_KERNEL);
> >         if (!optee)
> >                 return -ENOMEM;
> > +       optee->version_info = version_info;
> >
> >         pool = optee_ffa_shm_pool_alloc_pages();
> >         if (IS_ERR(pool)) {
> > diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
> > index db9ea673fbca..3e7bcd44976b 100644
> > --- a/drivers/tee/optee/optee_private.h
> > +++ b/drivers/tee/optee/optee_private.h
> > @@ -19,6 +19,22 @@
> >
> >  #define OPTEE_MAX_ARG_SIZE     1024
> >
> > +/**
> > + * struct optee_version_info - OP-TEE OS revision reported by secure world
> > + * @os_major:          OP-TEE OS major version
> > + * @os_minor:          OP-TEE OS minor version
> > + * @os_build_id:       OP-TEE OS build identifier (0 if unspecified)
> > + *
> > + * Values come from OPTEE_SMC_CALL_GET_OS_REVISION (SMC ABI) or
> > + * OPTEE_FFA_GET_OS_VERSION (FF-A ABI); this is the trusted OS revision, not an
> > + * FF-A ABI version.
> > + */
> > +struct optee_version_info {
> > +       u32 os_major;
> > +       u32 os_minor;
> > +       u64 os_build_id;
> > +};
> > +
> >  /* Some Global Platform error codes used in this driver */
> >  #define TEEC_SUCCESS                   0x00000000
> >  #define TEEC_ERROR_BAD_PARAMETERS      0xFFFF0006
> > @@ -249,6 +265,7 @@ struct optee {
> >         bool in_kernel_rpmb_routing;
> >         struct work_struct scan_bus_work;
> >         struct work_struct rpmb_scan_bus_work;
> > +       struct optee_version_info version_info;
> >  };
> >
> >  struct optee_session {
> > diff --git a/drivers/tee/optee/smc_abi.c b/drivers/tee/optee/smc_abi.c
> > index 0be663fcd52b..07c703609320 100644
> > --- a/drivers/tee/optee/smc_abi.c
> > +++ b/drivers/tee/optee/smc_abi.c
> > @@ -1323,7 +1323,8 @@ static bool optee_msg_api_uid_is_optee_image_load(optee_invoke_fn *invoke_fn)
> >  }
> >  #endif
> >
> > -static void optee_msg_get_os_revision(optee_invoke_fn *invoke_fn)
> > +static void optee_msg_get_os_revision(optee_invoke_fn *invoke_fn,
> > +                                     struct optee_version_info *version_info)
> >  {
> >         union {
> >                 struct arm_smccc_res smccc;
> > @@ -1337,6 +1338,12 @@ static void optee_msg_get_os_revision(optee_invoke_fn *invoke_fn)
> >         invoke_fn(OPTEE_SMC_CALL_GET_OS_REVISION, 0, 0, 0, 0, 0, 0, 0,
> >                   &res.smccc);
> >
> > +       if (version_info) {
> > +               version_info->os_major = res.result.major;
> > +               version_info->os_minor = res.result.minor;
> > +               version_info->os_build_id = res.result.build_id;
> > +       }
> > +
> >         if (res.result.build_id)
> >                 pr_info("revision %lu.%lu (%0*lx)", res.result.major,
> >                         res.result.minor, (int)sizeof(res.result.build_id) * 2,
> > @@ -1727,6 +1734,7 @@ static int optee_probe(struct platform_device *pdev)
> >         unsigned int thread_count;
> >         struct tee_device *teedev;
> >         struct tee_context *ctx;
> > +       struct optee_version_info version_info = { };
> >         u32 max_notif_value;
> >         u32 arg_cache_flags;
> >         u32 sec_caps;
> > @@ -1745,7 +1753,7 @@ static int optee_probe(struct platform_device *pdev)
> >                 return -EINVAL;
> >         }
> >
> > -       optee_msg_get_os_revision(invoke_fn);
> > +       optee_msg_get_os_revision(invoke_fn, &version_info);
> >
> >         if (!optee_msg_api_revision_is_compatible(invoke_fn)) {
> >                 pr_warn("api revision mismatch\n");
> > @@ -1814,6 +1822,7 @@ static int optee_probe(struct platform_device *pdev)
> >                 rc = -ENOMEM;
> >                 goto err_free_shm_pool;
> >         }
> > +       optee->version_info = version_info;
> >
> >         optee->ops = &optee_ops;
> >         optee->smc.invoke_fn = invoke_fn;
> > --
> > 2.43.0
> >