From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sumit Garg To: op-tee@lists.trustedfirmware.org Subject: Re: [PATCH v4 02/11] tee: add close_context to TEE driver operation Date: Wed, 14 May 2025 19:16:02 +0530 Message-ID: In-Reply-To: <=?utf-8?q?=3C20250428-qcom-tee-using-tee-ss-without-mem-obj-v4-?= =?utf-8?q?2-6a143640a6cb=40oss=2Equalcomm=2Ecom=3E?=> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="===============8283687263177223431==" List-Id: --===============8283687263177223431== Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable On Mon, Apr 28, 2025 at 11:06:23PM -0700, Amirreza Zarrabi wrote: > The tee_context can be used to manage TEE user resources, including > those allocated by the driver for the TEE on behalf of the user. > The release() callback is invoked only when all resources, such as > tee_shm, are released and there are no references to the tee_context. >=20 > When a user closes the device file, the driver should notify the > TEE to release any resources it may hold and drop the context > references. To achieve this, a close_context() callback is > introduced to initiate resource release in the TEE driver when > the device file is closed. >=20 > Relocate teedev_ctx_get, teedev_ctx_put, tee_device_get, and > tee_device_get functions to tee_core.h to make them accessible > outside the TEE subsystem. >=20 > Signed-off-by: Amirreza Zarrabi > --- > drivers/tee/tee_core.c | 7 +++++++ > drivers/tee/tee_private.h | 6 ------ > include/linux/tee_core.h | 50 +++++++++++++++++++++++++++++++++++++++++++= ++-- > 3 files changed, 55 insertions(+), 8 deletions(-) Reviewed-by: Sumit Garg -Sumit >=20 > diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c > index 24edce4cdbaa..721522fe5c63 100644 > --- a/drivers/tee/tee_core.c > +++ b/drivers/tee/tee_core.c > @@ -79,6 +79,7 @@ void teedev_ctx_get(struct tee_context *ctx) > =20 > kref_get(&ctx->refcount); > } > +EXPORT_SYMBOL_GPL(teedev_ctx_get); > =20 > static void teedev_ctx_release(struct kref *ref) > { > @@ -96,11 +97,15 @@ void teedev_ctx_put(struct tee_context *ctx) > =20 > kref_put(&ctx->refcount, teedev_ctx_release); > } > +EXPORT_SYMBOL_GPL(teedev_ctx_put); > =20 > void teedev_close_context(struct tee_context *ctx) > { > struct tee_device *teedev =3D ctx->teedev; > =20 > + if (teedev->desc->ops->close_context) > + teedev->desc->ops->close_context(ctx); > + > teedev_ctx_put(ctx); > tee_device_put(teedev); > } > @@ -1037,6 +1042,7 @@ void tee_device_put(struct tee_device *teedev) > } > mutex_unlock(&teedev->mutex); > } > +EXPORT_SYMBOL_GPL(tee_device_put); > =20 > bool tee_device_get(struct tee_device *teedev) > { > @@ -1049,6 +1055,7 @@ bool tee_device_get(struct tee_device *teedev) > mutex_unlock(&teedev->mutex); > return true; > } > +EXPORT_SYMBOL_GPL(tee_device_get); > =20 > /** > * tee_device_unregister() - Removes a TEE device > diff --git a/drivers/tee/tee_private.h b/drivers/tee/tee_private.h > index 9bc50605227c..d3f40a03de36 100644 > --- a/drivers/tee/tee_private.h > +++ b/drivers/tee/tee_private.h > @@ -14,12 +14,6 @@ > =20 > int tee_shm_get_fd(struct tee_shm *shm); > =20 > -bool tee_device_get(struct tee_device *teedev); > -void tee_device_put(struct tee_device *teedev); > - > -void teedev_ctx_get(struct tee_context *ctx); > -void teedev_ctx_put(struct tee_context *ctx); > - > struct tee_shm *tee_shm_alloc_user_buf(struct tee_context *ctx, size_t siz= e); > struct tee_shm *tee_shm_register_user_buf(struct tee_context *ctx, > unsigned long addr, size_t length); > diff --git a/include/linux/tee_core.h b/include/linux/tee_core.h > index a38494d6b5f4..284ca6b3e03a 100644 > --- a/include/linux/tee_core.h > +++ b/include/linux/tee_core.h > @@ -65,8 +65,9 @@ struct tee_device { > /** > * struct tee_driver_ops - driver operations vtable > * @get_version: returns version of driver > - * @open: called when the device file is opened > - * @release: release this open file > + * @open: called for a context when the device file is opened > + * @close_context: called when the device file is closed > + * @release: called to release the context > * @open_session: open a new session > * @close_session: close a session > * @system_session: declare session as a system session > @@ -76,11 +77,17 @@ struct tee_device { > * @supp_send: called for supplicant to send a response > * @shm_register: register shared memory buffer in TEE > * @shm_unregister: unregister shared memory buffer in TEE > + * > + * The context given to @open might last longer than the device file if it= is > + * tied to other resources in the TEE driver. @close_context is called whe= n the > + * client closes the device file, even if there are existing references to= the > + * context. The TEE driver can use @close_context to start cleaning up. > */ > struct tee_driver_ops { > void (*get_version)(struct tee_device *teedev, > struct tee_ioctl_version_data *vers); > int (*open)(struct tee_context *ctx); > + void (*close_context)(struct tee_context *ctx); > void (*release)(struct tee_context *ctx); > int (*open_session)(struct tee_context *ctx, > struct tee_ioctl_open_session_arg *arg, > @@ -154,6 +161,24 @@ int tee_device_register(struct tee_device *teedev); > */ > void tee_device_unregister(struct tee_device *teedev); > =20 > +/** > + * tee_device_get() - Increment the user count for a tee_device > + * @teedev: Pointer to the tee_device > + * > + * If tee_device_unregister() has been called and the final user of @teedev > + * has already released the device, this function will fail to prevent new= users > + * from accessing the device during the unregistration process. > + * > + * Returns: true if @teedev remains valid, otherwise false > + */ > +bool tee_device_get(struct tee_device *teedev); > + > +/** > + * tee_device_put() - Decrease the user count for a tee_device > + * @teedev: pointer to the tee_device > + */ > +void tee_device_put(struct tee_device *teedev); > + > /** > * tee_device_set_dev_groups() - Set device attribute groups > * @teedev: Device to register > @@ -315,4 +340,25 @@ struct tee_context *teedev_open(struct tee_device *tee= dev); > */ > void teedev_close_context(struct tee_context *ctx); > =20 > +/** > + * teedev_ctx_get() - Increment the reference count of a context > + * @ctx: Pointer to the context > + * > + * This function increases the refcount of the context, which is tied to > + * resources shared by the same tee_device. During the unregistration proc= ess, > + * the context may remain valid even after tee_device_unregister() has ret= urned. > + * > + * Users should ensure that the context's refcount is properly decreased b= efore > + * calling tee_device_put(), typically within the context's release() func= tion. > + * Alternatively, users can call tee_device_get() and teedev_ctx_get() tog= ether > + * and release them simultaneously (see shm_alloc_helper()). > + */ > +void teedev_ctx_get(struct tee_context *ctx); > + > +/** > + * teedev_ctx_put() - Decrease reference count on a context > + * @ctx: pointer to the context > + */ > +void teedev_ctx_put(struct tee_context *ctx); > + > #endif /*__TEE_CORE_H*/ >=20 > --=20 > 2.34.1 >=20 --===============8283687263177223431==--