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From: Sumit Garg <sumit.garg@linaro.org>
To: jens.wiklander@linaro.org, herbert@gondor.apana.org.au
Cc: mark.rutland@arm.com, Sumit Garg <sumit.garg@linaro.org>,
	daniel.thompson@linaro.org, michal.lkml@markovi.net,
	arnd@arndb.de, ard.biesheuvel@linaro.org,
	gregkh@linuxfoundation.org, bhsharma@redhat.com,
	linux-kernel@vger.kernel.org, tee-dev@lists.linaro.org,
	yamada.masahiro@socionext.com, robh+dt@kernel.org,
	linux-crypto@vger.kernel.org, mpm@selenic.com,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v6 2/4] tee: add supp_nowait flag in tee_context struct
Date: Tue, 29 Jan 2019 11:19:36 +0530
Message-ID: <1548740978-28495-3-git-send-email-sumit.garg@linaro.org> (raw)
In-Reply-To: <1548740978-28495-1-git-send-email-sumit.garg@linaro.org>

This flag indicates that requests in this context should not wait for
tee-supplicant daemon to be started if not present and just return
with an error code. It is needed for requests which should be
non-blocking in nature like ones arising from TEE based kernel drivers
or any in kernel api that uses TEE internal client interface.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
---
 drivers/tee/optee/supp.c | 10 +++++++++-
 drivers/tee/tee_core.c   | 13 +++++++++++++
 include/linux/tee_drv.h  |  6 ++++++
 3 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/drivers/tee/optee/supp.c b/drivers/tee/optee/supp.c
index 43626e1..92f56b8 100644
--- a/drivers/tee/optee/supp.c
+++ b/drivers/tee/optee/supp.c
@@ -88,10 +88,18 @@ u32 optee_supp_thrd_req(struct tee_context *ctx, u32 func, size_t num_params,
 {
 	struct optee *optee = tee_get_drvdata(ctx->teedev);
 	struct optee_supp *supp = &optee->supp;
-	struct optee_supp_req *req = kzalloc(sizeof(*req), GFP_KERNEL);
+	struct optee_supp_req *req;
 	bool interruptable;
 	u32 ret;
 
+	/*
+	 * Return in case there is no supplicant available and
+	 * non-blocking request.
+	 */
+	if (!supp->ctx && ctx->supp_nowait)
+		return TEEC_ERROR_COMMUNICATION;
+
+	req = kzalloc(sizeof(*req), GFP_KERNEL);
 	if (!req)
 		return TEEC_ERROR_OUT_OF_MEMORY;
 
diff --git a/drivers/tee/tee_core.c b/drivers/tee/tee_core.c
index 1e14897..25f3b9c 100644
--- a/drivers/tee/tee_core.c
+++ b/drivers/tee/tee_core.c
@@ -105,6 +105,11 @@ static int tee_open(struct inode *inode, struct file *filp)
 	if (IS_ERR(ctx))
 		return PTR_ERR(ctx);
 
+	/*
+	 * Default user-space behaviour is to wait for tee-supplicant
+	 * if not present for any requests in this context.
+	 */
+	ctx->supp_nowait = false;
 	filp->private_data = ctx;
 	return 0;
 }
@@ -981,6 +986,14 @@ tee_client_open_context(struct tee_context *start,
 	} while (IS_ERR(ctx) && PTR_ERR(ctx) != -ENOMEM);
 
 	put_device(put_dev);
+	/*
+	 * Default behaviour for in kernel client is to not wait for
+	 * tee-supplicant if not present for any requests in this context.
+	 * Also this flag could be configured again before call to
+	 * tee_client_open_session() if any in kernel client requires
+	 * different behaviour.
+	 */
+	ctx->supp_nowait = true;
 	return ctx;
 }
 EXPORT_SYMBOL_GPL(tee_client_open_context);
diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
index ce957ce..56d7f1b 100644
--- a/include/linux/tee_drv.h
+++ b/include/linux/tee_drv.h
@@ -50,6 +50,11 @@ struct tee_shm_pool;
  * @releasing:  flag that indicates if context is being released right now.
  *		It is needed to break circular dependency on context during
  *              shared memory release.
+ * @supp_nowait: flag that indicates that requests in this context should not
+ *              wait for tee-supplicant daemon to be started if not present
+ *              and just return with an error code. It is needed for requests
+ *              that arises from TEE based kernel drivers that should be
+ *              non-blocking in nature.
  */
 struct tee_context {
 	struct tee_device *teedev;
@@ -57,6 +62,7 @@ struct tee_context {
 	void *data;
 	struct kref refcount;
 	bool releasing;
+	bool supp_nowait;
 };
 
 struct tee_param_memref {
-- 
2.7.4


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  parent reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-29  5:49 [PATCH v6 0/4] Introduce TEE bus driver framework Sumit Garg
2019-01-29  5:49 ` [PATCH v6 1/4] tee: add bus driver framework for TEE based devices Sumit Garg
2019-01-29  5:49 ` Sumit Garg [this message]
2019-01-29  5:49 ` [PATCH v6 3/4] tee: optee: add TEE bus device enumeration support Sumit Garg
2019-02-01  8:28   ` Jens Wiklander
2019-02-01  8:42     ` Sumit Garg
2019-01-29  5:49 ` [PATCH v6 4/4] hwrng: add OP-TEE based rng driver Sumit Garg
2019-01-29  9:34   ` Daniel Thompson
2019-01-31  8:41 ` [PATCH v6 0/4] Introduce TEE bus driver framework Jens Wiklander
2019-01-31 12:05   ` Herbert Xu
2019-01-31 12:24     ` Sumit Garg
2019-02-12 11:05 ` Ard Biesheuvel
2019-02-12 12:09   ` Sumit Garg
2019-02-12 12:10     ` Ard Biesheuvel
2019-02-12 12:55       ` Sumit Garg

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