Re: [PATCH v4 2/2] tee: optee: store OS revision for TEE core

[Sumit Garg <sumit.garg@kernel.org>]

On Mon, Jan 05, 2026 at 04:13:52PM +0800, Aristo Chen wrote:
> Hi Sumit,
> 
> Sumit Garg <sumit.garg@kernel.org> 於 2026年1月5日週一 下午1:20寫道：
> >
> > On Tue, Dec 30, 2025 at 01:17:59PM +0800, Aristo Chen wrote:
> > > Collect OP-TEE OS revision from secure world for both SMC and FF-A ABIs,
> > > store it in the OP-TEE driver, and expose it through the generic
> > > get_tee_revision() callback.
> > >
> > > Signed-off-by: Aristo Chen <aristo.chen@canonical.com>
> > > ---
> > >  drivers/tee/optee/core.c          | 23 +++++++++++++++++++++++
> > >  drivers/tee/optee/ffa_abi.c       | 14 ++++++++++++--
> > >  drivers/tee/optee/optee_private.h | 19 +++++++++++++++++++
> > >  drivers/tee/optee/smc_abi.c       | 15 +++++++++++++--
> > >  4 files changed, 67 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
> > > index 5b62139714ce..2d807bc748bc 100644
> > > --- a/drivers/tee/optee/core.c
> > > +++ b/drivers/tee/optee/core.c
> > > @@ -63,6 +63,29 @@ int optee_set_dma_mask(struct optee *optee, u_int pa_width)
> > >       return dma_coerce_mask_and_coherent(&optee->teedev->dev, mask);
> > >  }
> > >
> > > +int optee_get_revision(struct tee_device *teedev, char *buf, size_t len)
> > > +{
> > > +     struct optee *optee = tee_get_drvdata(teedev);
> > > +     u64 build_id;
> > > +
> > > +     if (!optee)
> > > +             return -ENODEV;
> > > +     if (!buf || !len)
> > > +             return -EINVAL;
> > > +
> > > +     build_id = optee->revision.os_build_id;
> > > +     if (build_id)
> > > +             scnprintf(buf, len, "%u.%u (%016llx)",
> > > +                       optee->revision.os_major,
> > > +                       optee->revision.os_minor,
> > > +                       (unsigned long long)build_id);
> > > +     else
> > > +             scnprintf(buf, len, "%u.%u", optee->revision.os_major,
> > > +                       optee->revision.os_minor);
> > > +
> > > +     return 0;
> > > +}
> > > +
> > >  static void optee_bus_scan(struct work_struct *work)
> > >  {
> > >       WARN_ON(optee_enumerate_devices(PTA_CMD_GET_DEVICES_SUPP));
> > > diff --git a/drivers/tee/optee/ffa_abi.c b/drivers/tee/optee/ffa_abi.c
> > > index bf8390789ecf..d67ca1ec9506 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_revision *revision)
> > >  {
> > >       const struct ffa_msg_ops *msg_ops = ops->msg_ops;
> > >       struct ffa_send_direct_data data = {
> > > @@ -806,6 +807,11 @@ static bool optee_ffa_api_is_compatible(struct ffa_device *ffa_dev,
> > >               pr_err("Unexpected error %d\n", rc);
> > >               return false;
> > >       }
> > > +     if (revision) {
> > > +             revision->os_major = data.data0;
> > > +             revision->os_minor = data.data1;
> > > +             revision->os_build_id = data.data2;
> > > +     }
> > >       if (data.data2)
> > >               pr_info("revision %lu.%lu (%08lx)",
> > >                       data.data0, data.data1, data.data2);
> > > @@ -900,6 +906,7 @@ static int optee_ffa_open(struct tee_context *ctx)
> > >
> > >  static const struct tee_driver_ops optee_ffa_clnt_ops = {
> > >       .get_version = optee_ffa_get_version,
> > > +     .get_tee_revision = optee_get_revision,
> > >       .open = optee_ffa_open,
> > >       .release = optee_release,
> > >       .open_session = optee_open_session,
> > > @@ -918,6 +925,7 @@ static const struct tee_desc optee_ffa_clnt_desc = {
> > >
> > >  static const struct tee_driver_ops optee_ffa_supp_ops = {
> > >       .get_version = optee_ffa_get_version,
> > > +     .get_tee_revision = optee_get_revision,
> > >       .open = optee_ffa_open,
> > >       .release = optee_release_supp,
> > >       .supp_recv = optee_supp_recv,
> > > @@ -1034,6 +1042,7 @@ 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_revision revision = { };
> >
> > No need for this redundant variable on stack when...
> >
> > >       unsigned int max_notif_value;
> > >       unsigned int rpc_param_count;
> > >       struct tee_shm_pool *pool;
> > > @@ -1047,7 +1056,7 @@ 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, &revision))
> >
> > ...you can just invoke this API as rather:
> >
> >         if (!optee_ffa_api_is_compatible(ffa_dev, ffa_ops, &optee->revision))
> >
> Thanks for the review. To avoid the temporary struct optee_revision,
> I need to move the optee allocation earlier so we can pass
> &optee->revision into optee_ffa_api_is_compatible().

I would rather suggest to split this API to add a new one like
optee_ffa_get_os_revision() and then move it's invocation once optee
struct has been allocated.

> 
> AFAICT, there aren’t kernel selftests covering this, the only test that
> I am aware of is the xtest, so I’m slightly cautious about touching
> probe ordering. If you prefer to avoid the early allocation, I can keep
> the original order and use a local struct optee_revision instead.

With above suggestion, the probe ordering won't change much but rather
the point changes when you ask OP-TEE for it's revision.

-Sumit

> 
> Please let me know which you’d prefer
> 
> > >               return -EINVAL;
> > >
> > >       if (!optee_ffa_exchange_caps(ffa_dev, ffa_ops, &sec_caps,
> > > @@ -1059,6 +1068,7 @@ static int optee_ffa_probe(struct ffa_device *ffa_dev)
> > >       optee = kzalloc(sizeof(*optee), GFP_KERNEL);
> > >       if (!optee)
> > >               return -ENOMEM;
> > > +     optee->revision = revision;
> > >
> > >       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..acd3051c4879 100644
> > > --- a/drivers/tee/optee/optee_private.h
> > > +++ b/drivers/tee/optee/optee_private.h
> > > @@ -171,6 +171,24 @@ struct optee_ffa {
> > >
> > >  struct optee;
> > >
> > > +/**
> > > + * struct optee_revision - 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_revision {
> > > +     u32 os_major;
> > > +     u32 os_minor;
> > > +     u64 os_build_id;
> > > +};
> > > +
> > > +int optee_get_revision(struct tee_device *teedev, char *buf, size_t len);
> > > +
> > >  /**
> > >   * struct optee_ops - OP-TEE driver internal operations
> > >   * @do_call_with_arg:        enters OP-TEE in secure world
> > > @@ -249,6 +267,7 @@ struct optee {
> > >       bool in_kernel_rpmb_routing;
> > >       struct work_struct scan_bus_work;
> > >       struct work_struct rpmb_scan_bus_work;
> > > +     struct optee_revision revision;
> > >  };
> > >
> > >  struct optee_session {
> > > diff --git a/drivers/tee/optee/smc_abi.c b/drivers/tee/optee/smc_abi.c
> > > index 0be663fcd52b..0baaf7986a35 100644
> > > --- a/drivers/tee/optee/smc_abi.c
> > > +++ b/drivers/tee/optee/smc_abi.c
> > > @@ -1242,6 +1242,7 @@ static int optee_smc_open(struct tee_context *ctx)
> > >
> > >  static const struct tee_driver_ops optee_clnt_ops = {
> > >       .get_version = optee_get_version,
> > > +     .get_tee_revision = optee_get_revision,
> > >       .open = optee_smc_open,
> > >       .release = optee_release,
> > >       .open_session = optee_open_session,
> > > @@ -1261,6 +1262,7 @@ static const struct tee_desc optee_clnt_desc = {
> > >
> > >  static const struct tee_driver_ops optee_supp_ops = {
> > >       .get_version = optee_get_version,
> > > +     .get_tee_revision = optee_get_revision,
> > >       .open = optee_smc_open,
> > >       .release = optee_release_supp,
> > >       .supp_recv = optee_supp_recv,
> > > @@ -1323,7 +1325,8 @@ 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_revision *revision)
> > >  {
> > >       union {
> > >               struct arm_smccc_res smccc;
> > > @@ -1337,6 +1340,12 @@ 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 (revision) {
> > > +             revision->os_major = res.result.major;
> > > +             revision->os_minor = res.result.minor;
> > > +             revision->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 +1736,7 @@ static int optee_probe(struct platform_device *pdev)
> > >       unsigned int thread_count;
> > >       struct tee_device *teedev;
> > >       struct tee_context *ctx;
> > > +     struct optee_revision revision = { };
> >
> > Ditto here.
> >
> > -Sumit
> >
> > >       u32 max_notif_value;
> > >       u32 arg_cache_flags;
> > >       u32 sec_caps;
> > > @@ -1745,7 +1755,7 @@ static int optee_probe(struct platform_device *pdev)
> > >               return -EINVAL;
> > >       }
> > >
> > > -     optee_msg_get_os_revision(invoke_fn);
> > > +     optee_msg_get_os_revision(invoke_fn, &revision);
> > >
> > >       if (!optee_msg_api_revision_is_compatible(invoke_fn)) {
> > >               pr_warn("api revision mismatch\n");
> > > @@ -1837,6 +1847,7 @@ static int optee_probe(struct platform_device *pdev)
> > >               goto err_unreg_teedev;
> > >       }
> > >       optee->supp_teedev = teedev;
> > > +     optee->revision = revision;
> > >
> > >       optee_set_dev_group(optee);
> > >
> > > --
> > > 2.43.0
> > >
> 
> Best regards,
> Aristo