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Message-ID: <CAN5uoS_FLLMS2uUAZ9artSpx=mLS5ay+ybSL9XzPniU26Uuckw@mail.gmail.com>
Date: Fri, 20 Jan 2023 11:09:50 +0100
From: Etienne Carriere <etienne.carriere@...aro.org>
To: Jens Wiklander <jens.wiklander@...aro.org>
Cc: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
Sumit Garg <sumit.garg@...aro.org>,
Marc Zyngier <maz@...nel.org>,
Alexandre Torgue <alexandre.torgue@...s.st.com>
Subject: Re: [PATCH v2] optee: add per cpu asynchronous notification
Hello Jens,
Thanks for the feedback.
On Fri, 20 Jan 2023 at 09:33, Jens Wiklander <jens.wiklander@...aro.org> wrote:
>
> On Wed, Jan 18, 2023 at 06:49:09PM +0100, Etienne Carriere wrote:
> > Implements use of per CPU irq for optee asynchronous notification.
> >
> > Existing optee async notif implementation allows OP-TE world to
>
> allows OP-TEE in the secure world to
>
> > raise an interrupt for the Linux optee driver to query pending events
> > bound to waiting tasks in Linux world or threaded bottom half tasks
> > to be invoked in TEE world. This change allows the signaling interrupt
> > to be a per cpu interrupt as with Arm GIC PPIs.
> >
> > Cc: Jens Wiklander <jens.wiklander@...aro.org>
> > Cc: Sumit Garg <sumit.garg@...aro.org>
> > Cc: Marc Zyngier <maz@...nel.org>
> >
> > Co-developed-by: Alexandre Torgue <alexandre.torgue@...s.st.com>
> > Signed-off-by: Alexandre Torgue <alexandre.torgue@...s.st.com>
> > Signed-off-by: Etienne Carriere <etienne.carriere@...aro.org>
> > ---
> > Changes since v1:
> > - Fixed missing __percpu attribute reported by kernel test robot.
> > - Rephrased commit message and added Cc tags.
> > ---
> > drivers/tee/optee/optee_private.h | 22 ++++++
> > drivers/tee/optee/smc_abi.c | 107 ++++++++++++++++++++++++++++--
> > 2 files changed, 124 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
> > index 04ae58892608..e5bd3548691f 100644
> > --- a/drivers/tee/optee/optee_private.h
> > +++ b/drivers/tee/optee/optee_private.h
> > @@ -94,11 +94,33 @@ struct optee_supp {
> > struct completion reqs_c;
> > };
> >
> > +/*
> > + * struct optee_pcpu - per cpu notif private struct passed to work functions
> > + * @optee optee device reference
> > + */
> > +struct optee_pcpu {
> > + struct optee *optee;
> > +};
> > +
> > +/*
> > + * struct optee_smc - optee smc communication struct
> > + * @invoke_fn handler function to invoke secure monitor
> > + * @memremaped_shm virtual address of memory in shared memory pool
> > + * @sec_caps: secure world capabilities defined by
> > + * OPTEE_SMC_SEC_CAP_* in optee_smc.h
> > + * @notif_irq interrupt used as async notification by OP-TEE or 0
> > + * @optee_pcpu per_cpu optee instance for per cpu work or NULL
> > + * @notif_pcpu_wq workqueue for per cpu aynchronous notification or NULL
> > + * @notif_pcpu_work work for per cpu asynchronous notification
> > + */
> > struct optee_smc {
> > optee_invoke_fn *invoke_fn;
> > void *memremaped_shm;
> > u32 sec_caps;
> > unsigned int notif_irq;
> > + struct optee_pcpu __percpu *optee_pcpu;
> > + struct workqueue_struct *notif_pcpu_wq;
> > + struct work_struct notif_pcpu_work;
> > };
> >
> > /**
> > diff --git a/drivers/tee/optee/smc_abi.c b/drivers/tee/optee/smc_abi.c
> > index a1c1fa1a9c28..ffa3f3aa7244 100644
> > --- a/drivers/tee/optee/smc_abi.c
> > +++ b/drivers/tee/optee/smc_abi.c
> > @@ -993,12 +993,20 @@ static u32 get_async_notif_value(optee_invoke_fn *invoke_fn, bool *value_valid,
> >
> > static irqreturn_t notif_irq_handler(int irq, void *dev_id)
>
> Wouldn't it be easier with one handler for shared irqs and one for
> per-cpu irqs? The only common part is the do-while loop which I suppose
> could go into a helper function.
Ok, I do that.
>
> > {
> > - struct optee *optee = dev_id;
> > + struct optee *optee;
> > bool do_bottom_half = false;
> > bool value_valid;
> > bool value_pending;
> > u32 value;
> >
> > + if (irq_is_percpu_devid(irq)) {
> > + struct optee_pcpu __percpu *pcpu = (struct optee_pcpu *)dev_id;
> > +
> > + optee = pcpu->optee;
> > + } else {
> > + optee = dev_id;
> > + }
> > +
> > do {
> > value = get_async_notif_value(optee->smc.invoke_fn,
> > &value_valid, &value_pending);
> > @@ -1011,8 +1019,13 @@ static irqreturn_t notif_irq_handler(int irq, void *dev_id)
> > optee_notif_send(optee, value);
> > } while (value_pending);
> >
> > - if (do_bottom_half)
> > - return IRQ_WAKE_THREAD;
> > + if (do_bottom_half) {
> > + if (irq_is_percpu_devid(irq))
> > + queue_work(optee->smc.notif_pcpu_wq, &optee->smc.notif_pcpu_work);
>
> This line is a bit long, please break it.
ok, thanks.
>
> > + else
> > + return IRQ_WAKE_THREAD;
> > + }
> > +
> > return IRQ_HANDLED;
> > }
> >
> > @@ -1025,7 +1038,7 @@ static irqreturn_t notif_irq_thread_fn(int irq, void *dev_id)
> > return IRQ_HANDLED;
> > }
> >
> > -static int optee_smc_notif_init_irq(struct optee *optee, u_int irq)
> > +static int init_irq(struct optee *optee, u_int irq)
> > {
> > int rc;
> >
> > @@ -1040,12 +1053,96 @@ static int optee_smc_notif_init_irq(struct optee *optee, u_int irq)
> > return 0;
> > }
> >
> > +static void notif_pcpu_irq_work_fn(struct work_struct *work)
> > +{
> > + struct optee_smc *optee_smc = container_of(work, struct optee_smc, notif_pcpu_work);
>
> This line is a bit long, please break it.
ok.
>
> > + struct optee *optee = container_of(optee_smc, struct optee, smc);
> > +
> > + optee_smc_do_bottom_half(optee->ctx);
> > +}
> > +
> > +static int init_pcpu_irq(struct optee *optee, u_int irq)
> > +{
> > + struct optee_pcpu __percpu *optee_pcpu;
> > + spinlock_t lock;
> > + int cpu;
> > + int rc;
> > +
> > + optee_pcpu = alloc_percpu(struct optee_pcpu);
> > + if (!optee_pcpu)
> > + return -ENOMEM;
> > +
> > + for_each_present_cpu(cpu) {
> > + struct optee_pcpu __percpu *p = per_cpu_ptr(optee_pcpu, cpu);
> > +
> > + p->optee = optee;
> > + }
> > +
> > + rc = request_percpu_irq(irq, notif_irq_handler,
> > + "optee_pcpu_notification", optee_pcpu);
> > + if (rc)
> > + goto err_free_pcpu;
> > +
> > + spin_lock_init(&lock);
> > +
> > + spin_lock(&lock);
>
> What is the point with this spinlock?
Hmm... indeed. I'll remove.
>
> > + enable_percpu_irq(irq, 0);
> > + spin_unlock(&lock);
> > +
> > + INIT_WORK(&optee->smc.notif_pcpu_work, notif_pcpu_irq_work_fn);
> > + optee->smc.notif_pcpu_wq = create_workqueue("optee_pcpu_notification");
> > + if (!optee->smc.notif_pcpu_wq) {
> > + rc = -EINVAL;
> > + goto err_free_pcpu_irq;
> > + }
> > +
> > + optee->smc.optee_pcpu = optee_pcpu;
> > + optee->smc.notif_irq = irq;
> > +
> > + return 0;
> > +
> > +err_free_pcpu_irq:
> > + spin_lock(&lock);
> > + disable_percpu_irq(irq);
> > + spin_unlock(&lock);
> > + free_percpu_irq(irq, optee_pcpu);
> > +err_free_pcpu:
> > + free_percpu(optee_pcpu);
> > +
> > + return rc;
> > +}
> > +
> > +static int optee_smc_notif_init_irq(struct optee *optee, u_int irq)
> > +{
> > + if (irq_is_percpu_devid(irq))
> > + return init_pcpu_irq(optee, irq);
> > + else
> > + return init_irq(optee, irq);
> > +}
> > +
> > +static void uninit_pcpu_irq(struct optee *optee)
> > +{
> > + spinlock_t lock;
> > +
> > + spin_lock_init(&lock);
> > + spin_lock(&lock);
>
> What's the point with this spinlock?
>
>
> Cheers,
> Jens
>
> > + disable_percpu_irq(optee->smc.notif_irq);
> > + spin_unlock(&lock);
> > +
> > + free_percpu_irq(optee->smc.notif_irq, optee->smc.optee_pcpu);
> > + free_percpu(optee->smc.optee_pcpu);
> > +}
> > +
> > static void optee_smc_notif_uninit_irq(struct optee *optee)
> > {
> > if (optee->smc.sec_caps & OPTEE_SMC_SEC_CAP_ASYNC_NOTIF) {
> > optee_smc_stop_async_notif(optee->ctx);
> > if (optee->smc.notif_irq) {
> > - free_irq(optee->smc.notif_irq, optee);
> > + if (irq_is_percpu_devid(optee->smc.notif_irq))
> > + uninit_pcpu_irq(optee);
> > + else
> > + free_irq(optee->smc.notif_irq, optee);
> > +
> > irq_dispose_mapping(optee->smc.notif_irq);
> > }
> > }
> > --
> > 2.25.1
> >
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