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

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Message-ID: <CAHUa44G86Hg3BeRRvGvBOyOu4w0FryvDC4bMacW65J7uQuMG5g@mail.gmail.com>
Date: Mon, 6 May 2024 10:30:06 +0200
From: Jens Wiklander <jens.wiklander@...aro.org>
To: Gavin Liu (劉哲廷) <Gavin.Liu@...iatek.com>
Cc: "linux-arm-kernel@...ts.infradead.org" <linux-arm-kernel@...ts.infradead.org>, 
	"matthias.bgg@...il.com" <matthias.bgg@...il.com>, 
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, 
	"linux-mediatek@...ts.infradead.org" <linux-mediatek@...ts.infradead.org>, 
	"sumit.garg@...aro.org" <sumit.garg@...aro.org>, 
	"op-tee@...ts.trustedfirmware.org" <op-tee@...ts.trustedfirmware.org>
Subject: Re: [PATCH v2] optee: add timeout value to optee_notif_wait() to
 support timeout

On Mon, May 6, 2024 at 10:19 AM Gavin Liu (劉哲廷) <Gavin.Liu@...iatek.com> wrote:
>
> Hi Jens,
>
> Thanks for the reviews.
>
> On Mon, 2024-05-06 at 09:48 +0200, Jens Wiklander wrote:
> >
> > External email : Please do not click links or open attachments until
> > you have verified the sender or the content.
> >  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
>
> Ok, I'll change it.
>
> >
> > >   *
> > >   * 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
> >
>
> Agreed, we also use TEE_ERROR_TIMEOUT in the corresponding patch for
> optee-os. But, the "TEE_ERROR_TIMEOUT" is currently undefined in Linux
> Kernel. Do you have a suggestion for which header would be better to
> place it in?

Please put it in drivers/tee/optee/optee_private.h below
TEEC_ERROR_SHORT_BUFFER with a comment that it's from the GP TEE
Internal Core API Specification.

Cheers,
Jens