[v9,7/9] optee: support protected memory allocation

Add support in the OP-TEE backend driver for protected memory
allocation. The support is limited to only the SMC ABI and for secure
video buffers.

OP-TEE is probed for the range of protected physical memory and a
memory pool allocator is initialized if OP-TEE have support for such
memory.

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
---
 drivers/tee/optee/core.c          | 10 +++++++
 drivers/tee/optee/optee_private.h |  2 ++
 drivers/tee/optee/smc_abi.c       | 45 +++++++++++++++++++++++++++++--
 3 files changed, 55 insertions(+), 2 deletions(-)

On Mon, May 26, 2025 at 9:33 AM Sumit Garg <sumit.garg@kernel.org> wrote:
>
> On Tue, May 20, 2025 at 05:16:50PM +0200, Jens Wiklander wrote:
> > Add support in the OP-TEE backend driver for protected memory
> > allocation. The support is limited to only the SMC ABI and for secure
> > video buffers.
> >
> > OP-TEE is probed for the range of protected physical memory and a
> > memory pool allocator is initialized if OP-TEE have support for such
> > memory.
> >
> > Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
> > ---
> >  drivers/tee/optee/core.c          | 10 +++++++
> >  drivers/tee/optee/optee_private.h |  2 ++
> >  drivers/tee/optee/smc_abi.c       | 45 +++++++++++++++++++++++++++++--
> >  3 files changed, 55 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
> > index c75fddc83576..4b14a7ac56f9 100644
> > --- a/drivers/tee/optee/core.c
> > +++ b/drivers/tee/optee/core.c
> > @@ -56,6 +56,15 @@ int optee_rpmb_intf_rdev(struct notifier_block *intf, unsigned long action,
> >       return 0;
> >  }
> >
> > +int optee_set_dma_mask(struct optee *optee, u_int pa_width)
> > +{
> > +     u64 mask = DMA_BIT_MASK(min(64, pa_width));
> > +
> > +     optee->teedev->dev.dma_mask = &optee->teedev->dev.coherent_dma_mask;
> > +
> > +     return dma_set_mask_and_coherent(&optee->teedev->dev, mask);
> > +}
> > +
> >  static void optee_bus_scan(struct work_struct *work)
> >  {
> >       WARN_ON(optee_enumerate_devices(PTA_CMD_GET_DEVICES_SUPP));
> > @@ -181,6 +190,7 @@ void optee_remove_common(struct optee *optee)
> >       tee_device_unregister(optee->supp_teedev);
> >       tee_device_unregister(optee->teedev);
> >
> > +     tee_device_unregister_all_dma_heaps(optee->teedev);
> >       tee_shm_pool_free(optee->pool);
> >       optee_supp_uninit(&optee->supp);
> >       mutex_destroy(&optee->call_queue.mutex);
> > diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
> > index dc0f355ef72a..5e3c34802121 100644
> > --- a/drivers/tee/optee/optee_private.h
> > +++ b/drivers/tee/optee/optee_private.h
> > @@ -272,6 +272,8 @@ struct optee_call_ctx {
> >
> >  extern struct blocking_notifier_head optee_rpmb_intf_added;
> >
> > +int optee_set_dma_mask(struct optee *optee, u_int pa_width);
> > +
> >  int optee_notif_init(struct optee *optee, u_int max_key);
> >  void optee_notif_uninit(struct optee *optee);
> >  int optee_notif_wait(struct optee *optee, u_int key, u32 timeout);
> > diff --git a/drivers/tee/optee/smc_abi.c b/drivers/tee/optee/smc_abi.c
> > index f0c3ac1103bb..f3cae8243785 100644
> > --- a/drivers/tee/optee/smc_abi.c
> > +++ b/drivers/tee/optee/smc_abi.c
> > @@ -1584,6 +1584,42 @@ static inline int optee_load_fw(struct platform_device *pdev,
> >  }
> >  #endif
> >
> > +static int optee_protmem_pool_init(struct optee *optee)
> > +{
> > +     enum tee_dma_heap_id heap_id = TEE_DMA_HEAP_SECURE_VIDEO_PLAY;
> > +     struct tee_protmem_pool *pool;
> > +     int rc;
> > +
> > +     if (optee->smc.sec_caps & OPTEE_SMC_SEC_CAP_PROTMEM) {
> > +             union {
> > +                     struct arm_smccc_res smccc;
> > +                     struct optee_smc_get_protmem_config_result result;
> > +             } res;
> > +
> > +             optee->smc.invoke_fn(OPTEE_SMC_GET_PROTMEM_CONFIG, 0, 0, 0, 0,
> > +                                  0, 0, 0, &res.smccc);
> > +             if (res.result.status != OPTEE_SMC_RETURN_OK) {
> > +                     pr_err("Secure Data Path service not available\n");
> > +                     return 0;
> > +             }
> > +             rc = optee_set_dma_mask(optee, res.result.pa_width);
> > +             if (!rc)
> > +                     pool = tee_protmem_static_pool_alloc(res.result.start,
> > +                                                          res.result.size);
> > +             if (IS_ERR(pool))
> > +                     return PTR_ERR(pool);
> > +
> > +             rc = tee_device_register_dma_heap(optee->teedev, heap_id, pool);
> > +             if (rc)
> > +                     goto err;
> > +     }
> > +
> > +     return 0;
> > +err:
> > +     pool->ops->destroy_pool(pool);
> > +     return rc;
> > +}
> > +
> >  static int optee_probe(struct platform_device *pdev)
> >  {
> >       optee_invoke_fn *invoke_fn;
> > @@ -1679,7 +1715,7 @@ static int optee_probe(struct platform_device *pdev)
> >       optee = kzalloc(sizeof(*optee), GFP_KERNEL);
> >       if (!optee) {
> >               rc = -ENOMEM;
> > -             goto err_free_pool;
> > +             goto err_free_shm_pool;
> >       }
> >
> >       optee->ops = &optee_ops;
> > @@ -1752,6 +1788,10 @@ static int optee_probe(struct platform_device *pdev)
> >               pr_info("Asynchronous notifications enabled\n");
> >       }
> >
> > +     rc = optee_protmem_pool_init(optee);
>
> Here we should do a Kconfig check for CONFIG_DMABUF_HEAPS so that we
> don't proceed any further with initialization.

Why? If OP-TEE is configured for protected memory but the kernel
isn't, something isn't right, and a print could be useful.

Cheers,
Jens

>
> Rest looks good to me.
>
> -Sumit
>
> > +     if (rc)
> > +             goto err_notif_uninit;
> > +
> >       /*
> >        * Ensure that there are no pre-existing shm objects before enabling
> >        * the shm cache so that there's no chance of receiving an invalid
> > @@ -1787,6 +1827,7 @@ static int optee_probe(struct platform_device *pdev)
> >               optee_disable_shm_cache(optee);
> >       optee_smc_notif_uninit_irq(optee);
> >       optee_unregister_devices();
> > +     tee_device_unregister_all_dma_heaps(optee->teedev);
> >  err_notif_uninit:
> >       optee_notif_uninit(optee);
> >  err_close_ctx:
> > @@ -1803,7 +1844,7 @@ static int optee_probe(struct platform_device *pdev)
> >       tee_device_unregister(optee->teedev);
> >  err_free_optee:
> >       kfree(optee);
> > -err_free_pool:
> > +err_free_shm_pool:
> >       tee_shm_pool_free(pool);
> >       if (memremaped_shm)
> >               memunmap(memremaped_shm);
> > --
> > 2.43.0
> >