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Date:   Thu, 30 Mar 2023 11:22:10 +0200
From:   Jens Wiklander <jens.wiklander@linaro.org>
To:     Sumit Garg <sumit.garg@linaro.org>
Cc:     Etienne Carriere <etienne.carriere@linaro.org>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        op-tee@lists.trustedfirmware.org, Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Marc Zyngier <maz@kernel.org>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>
Subject: Re: [PATCH v6 2/2] optee: add per cpu asynchronous notification
Message-ID: <20230330092210.GA990388@rayden>
References: <20230322132212.3646972-1-etienne.carriere@linaro.org>
 <20230322132212.3646972-2-etienne.carriere@linaro.org>
 <CAFA6WYP16n9MkC5mQnRXMBsCqVLQyfLejk1Vt1Z6o=XPX6ccAQ@mail.gmail.com>
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On Wed, Mar 22, 2023 at 08:28:11PM +0530, Sumit Garg wrote:
> On Wed, 22 Mar 2023 at 18:52, Etienne Carriere
> <etienne.carriere@linaro.org> wrote:
> >
> > Implements use of per-cpu irq for optee asynchronous notification.
> >
> > Existing optee async notif implementation allows OP-TEE world to
> > raise an interrupt on which Linux optee driver will query some pending
> > events. This change allows the signaling interrupt to be a per-cpu
> > interrupt as with Arm GIC PPIs. Using a PPI instead of an SPI is useful
> > when no GIC lines are provisioned in the chip design and there are spare
> > PPI lines.
> >
> > Cc: Jens Wiklander <jens.wiklander@linaro.org>
> > Cc: Sumit Garg <sumit.garg@linaro.org>
> > Cc: Marc Zyngier <maz@kernel.org>
> >
> > Co-developed-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
> > Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>
> > Signed-off-by: Etienne Carriere <etienne.carriere@linaro.org>
> > ---
> > Changes since v5:
> > - Removed spurious __percpu attributes reported by kernel test robot
> >   (https://lore.kernel.org/lkml/202303190039.RsU7kCIu-lkp@intel.com/).
> >
> 
> Apart from nit below, feel free to add:
> 
> Reviewed-by: Sumit Garg <sumit.garg@linaro.org>
> 
> > Changes since v4:
> > - Used cpuhp_setup_state()/cpuhp_remove_state() to enable/disable the
> >   per-cpu interrupt and let CPU hotplug also manage it.
> > - Added a call to destroy_workqueue() that was missing in uninit_pcpu_irq().
> > - Rephrased commit message.
> >
> > Changes since v3:
> > - Fixed typo in commit message.
> > - Added few words in commit message about why we do this change.
> > - Appended a 2nd commit to the series for request DT bindings update.
> >
> > Changes since v2:
> > - Irq and per-cpu irq no more share the primary same handler function
> >   but have a common irq_handler() helper function.
> > - Removed useless spinlocks.
> > - Wrapped lines > 80 char.
> >
> > 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 |  24 ++++++
> >  drivers/tee/optee/smc_abi.c       | 122 +++++++++++++++++++++++++++++-
> >  2 files changed, 142 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
> > index 04ae58892608..6129d43dd354 100644
> > --- a/drivers/tee/optee/optee_private.h
> > +++ b/drivers/tee/optee/optee_private.h
> > @@ -94,11 +94,35 @@ 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
> 
> s/aynchronous/asynchronous/

I'm picking up this and I'll fix the spell error too.

Thanks,
Jens

> 
> -Sumit
> 
> > + * @notif_pcpu_work    work for per cpu asynchronous notification
> > + * @notif_cpuhp_state   CPU hotplug state assigned for pcpu interrupt management
> > + */
> >  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;
> > +       unsigned int notif_cpuhp_state;
> >  };
> >
> >  /**
> > diff --git a/drivers/tee/optee/smc_abi.c b/drivers/tee/optee/smc_abi.c
> > index a1c1fa1a9c28..de7ac9a46354 100644
> > --- a/drivers/tee/optee/smc_abi.c
> > +++ b/drivers/tee/optee/smc_abi.c
> > @@ -52,6 +52,23 @@
> >   */
> >  #define OPTEE_MIN_STATIC_POOL_ALIGN    9 /* 512 bytes aligned */
> >
> > +/* SMC ABI considers at most a single TEE firmware */
> > +static unsigned int pcpu_irq_num;
> > +
> > +static int optee_cpuhp_enable_pcpu_irq(unsigned int cpu)
> > +{
> > +       enable_percpu_irq(pcpu_irq_num, IRQ_TYPE_NONE);
> > +
> > +       return 0;
> > +}
> > +
> > +static int optee_cpuhp_disable_pcpu_irq(unsigned int cpu)
> > +{
> > +       disable_percpu_irq(pcpu_irq_num);
> > +
> > +       return 0;
> > +}
> > +
> >  /*
> >   * 1. Convert between struct tee_param and struct optee_msg_param
> >   *
> > @@ -991,9 +1008,8 @@ static u32 get_async_notif_value(optee_invoke_fn *invoke_fn, bool *value_valid,
> >         return res.a1;
> >  }
> >
> > -static irqreturn_t notif_irq_handler(int irq, void *dev_id)
> > +static irqreturn_t irq_handler(struct optee *optee)
> >  {
> > -       struct optee *optee = dev_id;
> >         bool do_bottom_half = false;
> >         bool value_valid;
> >         bool value_pending;
> > @@ -1016,6 +1032,13 @@ static irqreturn_t notif_irq_handler(int irq, void *dev_id)
> >         return IRQ_HANDLED;
> >  }
> >
> > +static irqreturn_t notif_irq_handler(int irq, void *dev_id)
> > +{
> > +       struct optee *optee = dev_id;
> > +
> > +       return irq_handler(optee);
> > +}
> > +
> >  static irqreturn_t notif_irq_thread_fn(int irq, void *dev_id)
> >  {
> >         struct optee *optee = dev_id;
> > @@ -1025,7 +1048,7 @@ 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 +1063,103 @@ static int optee_smc_notif_init_irq(struct optee *optee, u_int irq)
> >         return 0;
> >  }
> >
> > +static irqreturn_t notif_pcpu_irq_handler(int irq, void *dev_id)
> > +{
> > +       struct optee_pcpu *pcpu = dev_id;
> > +       struct optee *optee = pcpu->optee;
> > +
> > +       if (irq_handler(optee) == IRQ_WAKE_THREAD)
> > +               queue_work(optee->smc.notif_pcpu_wq,
> > +                          &optee->smc.notif_pcpu_work);
> > +
> > +       return IRQ_HANDLED;
> > +}
> > +
> > +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);
> > +       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;
> > +       int cpu, rc;
> > +
> > +       optee_pcpu = alloc_percpu(struct optee_pcpu);
> > +       if (!optee_pcpu)
> > +               return -ENOMEM;
> > +
> > +       for_each_present_cpu(cpu)
> > +               per_cpu_ptr(optee_pcpu, cpu)->optee = optee;
> > +
> > +       rc = request_percpu_irq(irq, notif_pcpu_irq_handler,
> > +                               "optee_pcpu_notification", optee_pcpu);
> > +       if (rc)
> > +               goto err_free_pcpu;
> > +
> > +       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;
> > +
> > +       pcpu_irq_num = irq;
> > +       rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "optee/pcpu-notif:starting",
> > +                              optee_cpuhp_enable_pcpu_irq,
> > +                              optee_cpuhp_disable_pcpu_irq);
> > +       if (!rc)
> > +               rc = -EINVAL;
> > +       if (rc < 0)
> > +               goto err_free_pcpu_irq;
> > +
> > +       optee->smc.notif_cpuhp_state = rc;
> > +
> > +       return 0;
> > +
> > +err_free_pcpu_irq:
> > +       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)
> > +{
> > +       cpuhp_remove_state(optee->smc.notif_cpuhp_state);
> > +
> > +       destroy_workqueue(optee->smc.notif_pcpu_wq);
> > +
> > +       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
> >