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Message-ID: <Y8pR1Bm7TQdtI7x5@jade>
Date: Fri, 20 Jan 2023 09:33:24 +0100
From: Jens Wiklander <jens.wiklander@...aro.org>
To: Etienne Carriere <etienne.carriere@...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
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.
> {
> - 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.
> + 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.
> + 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?
> + 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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