From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7F6A719BBC; Wed, 14 May 2025 13:46:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747230370; cv=none; b=Le9HfIOnMCswWiXE45RAxUliDFeXH9gO3FFKPzBDtofaoeQ0eQMk7FyMjmQeu9t2WrOVAGnVxp1pQ6xCwSHe35kGN6ohdurs1UEO8Bf3ug2G4p8ZPjoPodgjXKQvp01vdhhZB7NogDiaMZ8ixHWdqR1fEtcn0cVULp5BRcMVDB4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747230370; c=relaxed/simple; bh=OSrnGbk3XZitVici2vvw4FrrBrgrXyPGRNPFbZ/9Nc0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AqCjkxx9OdijGSJOuapAZn/KINAZYBVsKvhgUpVikei/r1WdoIPRlPDLGFDKEOKsfBf/XOZEAyfs9BTMix+C6roq2tI7IT4o1Mnuwbzce9Y12M0W0IcIZ5sVMrTfqUGmVyORQDkjrmSo4yAF96UKDXi7YP94emGcJT6MR5zjEJE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cQqW15L1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cQqW15L1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 21211C4CEED; Wed, 14 May 2025 13:46:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747230370; bh=OSrnGbk3XZitVici2vvw4FrrBrgrXyPGRNPFbZ/9Nc0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cQqW15L1hp91wSceRJocjBpoaz+A9SMKaGotCjeLtiYhDKTvcvJDLVscfC//bpZ9x mg440qDns6sjosEvae91Z5B7TCO0HlC2yoKiMiYJxw1DRfZtH3+zSfz/DAMenk3G7C IGajUTl8HoKgl9p4jwA7p4ymheJmnNPFG5Y/SnmhDJxfVmgkVxsclv75SQZWRPBNWa n3f+ZuCgHl/M+H7zabrdBKgfSPbPFsy5JSNZhwL3p91vaN7V8kAUpLRx0RU6k4UeCd rPXcc0piicDjPFJKjb7n61P6pme7dDdKmHTXQ7TnWY6KDVDi7ZpP56xtb+aEVSQY/R KYMrOKydQUaOA== Date: Wed, 14 May 2025 19:16:02 +0530 From: Sumit Garg To: Amirreza Zarrabi Cc: Jens Wiklander , Bjorn Andersson , Konrad Dybcio , Bartosz Golaszewski , Apurupa Pattapu , Kees Cook , "Gustavo A. R. Silva" , Sumit Semwal , Christian =?iso-8859-1?Q?K=F6nig?= , linux-arm-msm@vger.kernel.org, op-tee@lists.trustedfirmware.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-doc@vger.kernel.org Subject: Re: [PATCH v4 02/11] tee: add close_context to TEE driver operation Message-ID: References: <20250428-qcom-tee-using-tee-ss-without-mem-obj-v4-0-6a143640a6cb@oss.qualcomm.com> <20250428-qcom-tee-using-tee-ss-without-mem-obj-v4-2-6a143640a6cb@oss.qualcomm.com> Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250428-qcom-tee-using-tee-ss-without-mem-obj-v4-2-6a143640a6cb@oss.qualcomm.com> 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. > > 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. > > 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. > > 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 > > 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) > > kref_get(&ctx->refcount); > } > +EXPORT_SYMBOL_GPL(teedev_ctx_get); > > static void teedev_ctx_release(struct kref *ref) > { > @@ -96,11 +97,15 @@ void teedev_ctx_put(struct tee_context *ctx) > > kref_put(&ctx->refcount, teedev_ctx_release); > } > +EXPORT_SYMBOL_GPL(teedev_ctx_put); > > void teedev_close_context(struct tee_context *ctx) > { > struct tee_device *teedev = ctx->teedev; > > + 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); > > 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); > > /** > * 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 @@ > > int tee_shm_get_fd(struct tee_shm *shm); > > -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 size); > 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 when 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); > > +/** > + * 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 *teedev); > */ > void teedev_close_context(struct tee_context *ctx); > > +/** > + * 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 process, > + * the context may remain valid even after tee_device_unregister() has returned. > + * > + * Users should ensure that the context's refcount is properly decreased before > + * calling tee_device_put(), typically within the context's release() function. > + * Alternatively, users can call tee_device_get() and teedev_ctx_get() together > + * 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*/ > > -- > 2.34.1 >