linux-kernel - Re: [PATCH v2] optee: add timeout value to optee_notif

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Message-ID: <CAHUa44GGzMQjrkFm4JRQ463wqOpZfzoo91TchK=PdH1Rt565pQ@mail.gmail.com>
Date: Mon, 6 May 2024 09:48:01 +0200
From: Jens Wiklander <jens.wiklander@...aro.org>
To: "gavin.liu" <gavin.liu@...iatek.com>
Cc: Sumit Garg <sumit.garg@...aro.org>, Matthias Brugger <matthias.bgg@...il.com>, 
	op-tee@...ts.trustedfirmware.org, linux-kernel@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, linux-mediatek@...ts.infradead.org
Subject: Re: [PATCH v2] optee: add timeout value to optee_notif_wait() to
 support timeout

On Thu, May 2, 2024 at 10:56 AM gavin.liu <gavin.liu@...iatek.com> wrote:
>
> From: Gavin Liu <gavin.liu@...iatek.com>
>
> Add timeout value to support self waking when timeout to avoid waiting
> indefinitely.
>
> Signed-off-by: Gavin Liu <gavin.liu@...iatek.com>
> ---
> Change in v2:
> Change commit message.
> Add description for value[0].c in optee_rpc_cmd.h.
> ---
> ---
>  drivers/tee/optee/notif.c         |  9 +++++++--
>  drivers/tee/optee/optee_private.h |  2 +-
>  drivers/tee/optee/optee_rpc_cmd.h |  1 +
>  drivers/tee/optee/rpc.c           | 10 ++++++++--
>  4 files changed, 17 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/tee/optee/notif.c b/drivers/tee/optee/notif.c
> index 05212842b0a5..d5e5c0645609 100644
> --- a/drivers/tee/optee/notif.c
> +++ b/drivers/tee/optee/notif.c
> @@ -29,7 +29,7 @@ static bool have_key(struct optee *optee, u_int key)
>         return false;
>  }
>
> -int optee_notif_wait(struct optee *optee, u_int key)
> +int optee_notif_wait(struct optee *optee, u_int key, u32 timeout)
>  {
>         unsigned long flags;
>         struct notif_entry *entry;
> @@ -70,7 +70,12 @@ int optee_notif_wait(struct optee *optee, u_int key)
>          * Unlock temporarily and wait for completion.
>          */
>         spin_unlock_irqrestore(&optee->notif.lock, flags);
> -       wait_for_completion(&entry->c);
> +       if (timeout != 0) {
> +               if (!wait_for_completion_timeout(&entry->c, timeout))
> +                       rc = -ETIMEDOUT;
> +       } else {
> +               wait_for_completion(&entry->c);
> +       }
>         spin_lock_irqsave(&optee->notif.lock, flags);
>
>         list_del(&entry->link);
> diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
> index 7a5243c78b55..da990c4016ec 100644
> --- a/drivers/tee/optee/optee_private.h
> +++ b/drivers/tee/optee/optee_private.h
> @@ -252,7 +252,7 @@ struct optee_call_ctx {
>
>  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);
> +int optee_notif_wait(struct optee *optee, u_int key, u32 timeout);
>  int optee_notif_send(struct optee *optee, u_int key);
>
>  u32 optee_supp_thrd_req(struct tee_context *ctx, u32 func, size_t num_params,
> diff --git a/drivers/tee/optee/optee_rpc_cmd.h b/drivers/tee/optee/optee_rpc_cmd.h
> index f3f06e0994a7..99342aa66263 100644
> --- a/drivers/tee/optee/optee_rpc_cmd.h
> +++ b/drivers/tee/optee/optee_rpc_cmd.h
> @@ -41,6 +41,7 @@
>   * Waiting on notification
>   * [in]    value[0].a      OPTEE_RPC_NOTIFICATION_WAIT
>   * [in]    value[0].b      notification value
> + * [in]    value[0].c      timeout in millisecond or 0 if no timeout

milliseconds

>   *
>   * Sending a synchronous notification
>   * [in]    value[0].a      OPTEE_RPC_NOTIFICATION_SEND
> diff --git a/drivers/tee/optee/rpc.c b/drivers/tee/optee/rpc.c
> index e69bc6380683..14e6246aaf05 100644
> --- a/drivers/tee/optee/rpc.c
> +++ b/drivers/tee/optee/rpc.c
> @@ -130,6 +130,8 @@ static void handle_rpc_func_cmd_i2c_transfer(struct tee_context *ctx,
>  static void handle_rpc_func_cmd_wq(struct optee *optee,
>                                    struct optee_msg_arg *arg)
>  {
> +       int rc = 0;
> +
>         if (arg->num_params != 1)
>                 goto bad;
>
> @@ -139,7 +141,8 @@ static void handle_rpc_func_cmd_wq(struct optee *optee,
>
>         switch (arg->params[0].u.value.a) {
>         case OPTEE_RPC_NOTIFICATION_WAIT:
> -               if (optee_notif_wait(optee, arg->params[0].u.value.b))
> +               rc = optee_notif_wait(optee, arg->params[0].u.value.b, arg->params[0].u.value.c);
> +               if (rc)
>                         goto bad;
>                 break;
>         case OPTEE_RPC_NOTIFICATION_SEND:
> @@ -153,7 +156,10 @@ static void handle_rpc_func_cmd_wq(struct optee *optee,
>         arg->ret = TEEC_SUCCESS;
>         return;
>  bad:
> -       arg->ret = TEEC_ERROR_BAD_PARAMETERS;
> +       if (rc == -ETIMEDOUT)
> +               arg->ret = TEEC_ERROR_BUSY;

TEEC_ERROR_BUSY is confusing. How about TEE_ERROR_TIMEOUT? We normally
only use TEEC_XXX error codes, but GP doesn't define a
TEEC_ERROR_TIMEOUT so it's better to use the GP-defined
TEE_ERROR_TIMEOUT.

Cheers,
Jens

> +       else
> +               arg->ret = TEEC_ERROR_BAD_PARAMETERS;
>  }
>
>  static void handle_rpc_func_cmd_wait(struct optee_msg_arg *arg)
> --
> 2.18.0
>