From 53130568be92e01af48749d5474d2aa328aac94b Mon Sep 17 00:00:00 2001 From: Kai Vehmanen Date: Fri, 27 Feb 2026 16:59:02 +0200 Subject: [PATCH 1/3] schedule: add scheduler_init_context() Add an optional method that allow the schedule.h user to get access to the thread context that will be used for scheduling. This is critical when the callbacks are run in user-space context and schedule.h client needs to grant access to objects like locks to the callback thread. Signed-off-by: Kai Vehmanen --- src/include/sof/schedule/schedule.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/src/include/sof/schedule/schedule.h b/src/include/sof/schedule/schedule.h index bbdcbbecf3b4..9418064beb02 100644 --- a/src/include/sof/schedule/schedule.h +++ b/src/include/sof/schedule/schedule.h @@ -158,6 +158,16 @@ struct scheduler_ops { * This operation is optional. */ int (*scheduler_restore)(void *data); + + /** + * Initializes context + * @param data Private data of selected scheduler. + * @param task task that needs to be scheduled + * @return thread that will be used to run the scheduled task + * + * This operation is optional. + */ + struct k_thread *(*scheduler_init_context)(void *data, struct task *task); }; /** \brief Holds information about scheduler. */ @@ -379,6 +389,24 @@ static inline int schedulers_restore(void) return 0; } +/** See scheduler_ops::scheduler_init_context */ +static inline struct k_thread *scheduler_init_context(struct task *task) +{ + struct schedulers *schedulers = *arch_schedulers_get(); + struct schedule_data *sch; + struct list_item *slist; + + assert(schedulers); + + list_for_item(slist, &schedulers->list) { + sch = container_of(slist, struct schedule_data, list); + if (task->type == sch->type && sch->ops->scheduler_init_context) + return sch->ops->scheduler_init_context(sch->data, task); + } + + return NULL; +} + /** * Initializes scheduling task. * @param task Task to be initialized. From 306553a2b39a9d963053a66ab48770755386b4c8 Mon Sep 17 00:00:00 2001 From: Kai Vehmanen Date: Wed, 4 Mar 2026 19:25:43 +0200 Subject: [PATCH 2/3] schedule: ll_schedule_domain: add domain_thread_init/free ops Add new domain ops that are called from privileged context and are used to set up resources like threads and initialize other kernel objects. Signed-off-by: Kai Vehmanen --- src/include/sof/schedule/ll_schedule_domain.h | 39 +++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/src/include/sof/schedule/ll_schedule_domain.h b/src/include/sof/schedule/ll_schedule_domain.h index dc28e43c7461..2c285a6e5586 100644 --- a/src/include/sof/schedule/ll_schedule_domain.h +++ b/src/include/sof/schedule/ll_schedule_domain.h @@ -43,6 +43,20 @@ struct ll_schedule_domain_ops { void (*handler)(void *arg), void *arg); int (*domain_unregister)(struct ll_schedule_domain *domain, struct task *task, uint32_t num_tasks); +#if CONFIG_SOF_USERSPACE_LL + /* + * Initialize the scheduling thread and perform all privileged setup + * (thread creation, timer init, access grants). Called once from + * kernel context before any user-space domain_register() calls. + */ + int (*domain_thread_init)(struct ll_schedule_domain *domain, + struct task *task); + /* Free resources acquired by domain_thread_init(). Called from + * kernel context when the scheduling context is being torn down. + */ + void (*domain_thread_free)(struct ll_schedule_domain *domain, + uint32_t num_tasks); +#endif void (*domain_enable)(struct ll_schedule_domain *domain, int core); void (*domain_disable)(struct ll_schedule_domain *domain, int core); #if CONFIG_CROSS_CORE_STREAM @@ -177,6 +191,31 @@ static inline void domain_task_cancel(struct ll_schedule_domain *domain, domain->ops->domain_task_cancel(domain, task); } +#if CONFIG_SOF_USERSPACE_LL +/* + * Initialize the scheduling thread and do all privileged setup. + * Must be called from kernel context before user-space tasks register. + */ +static inline int domain_thread_init(struct ll_schedule_domain *domain, + struct task *task) +{ + assert(domain->ops->domain_thread_init); + + return domain->ops->domain_thread_init(domain, task); +} + +/* + * Free resources acquired by domain_thread_init(). + * Must be called from kernel context. + */ +static inline void domain_thread_free(struct ll_schedule_domain *domain, + uint32_t num_tasks) +{ + if (domain->ops->domain_thread_free) + domain->ops->domain_thread_free(domain, num_tasks); +} +#endif + static inline int domain_register(struct ll_schedule_domain *domain, struct task *task, void (*handler)(void *arg), void *arg) From 04e2cf31a24b2cd81dba97676ef4c7e535aa6a5f Mon Sep 17 00:00:00 2001 From: Kai Vehmanen Date: Mon, 25 May 2026 13:52:46 +0300 Subject: [PATCH 3/3] schedule: zephyr_ll: implement user/kernel split with init_context() Use the new scheduler_init_context() and domain_thread_init/free() interfaces to separate LL scheduler logic into privileged and unprivileged parts. The latter can be used by the audio pipeline to add, remove and schedule tasks from the user-space audio thread. The privileged interfaces are used to set up the scheduler during firmware boot. Signed-off-by: Kai Vehmanen --- src/schedule/zephyr_domain.c | 172 ++++++++++++++++++++++++----------- src/schedule/zephyr_ll.c | 48 +++++++--- 2 files changed, 158 insertions(+), 62 deletions(-) diff --git a/src/schedule/zephyr_domain.c b/src/schedule/zephyr_domain.c index ebf5aea8d4d2..daace8bac708 100644 --- a/src/schedule/zephyr_domain.c +++ b/src/schedule/zephyr_domain.c @@ -126,7 +126,8 @@ static void zephyr_domain_thread_fn(void *p1, void *p2, void *p3) } #endif - dt->handler(dt->arg); + if (dt->handler) + dt->handler(dt->arg); #ifdef CONFIG_SCHEDULE_LL_STATS_LOG cycles1 = k_cycle_get_32(); @@ -289,63 +290,65 @@ static int zephyr_domain_unregister(struct ll_schedule_domain *domain, #else /* CONFIG_SOF_USERSPACE_LL */ -/* User-space implementation for register/unregister */ - -static int zephyr_domain_register_user(struct ll_schedule_domain *domain, - struct task *task, - void (*handler)(void *arg), void *arg) +/* + * Privileged thread initialization for userspace LL scheduling. + * Creates the scheduling thread, sets up timer, grants access to kernel + * objects. Must be called from kernel context before any user-space + * domain_register() calls. + */ +static int zephyr_domain_thread_init(struct ll_schedule_domain *domain, + struct task *task) { struct zephyr_domain *zephyr_domain = ll_sch_domain_get_pdata(domain); - int core = cpu_get_id(); - struct zephyr_domain_thread *dt = zephyr_domain->domain_thread + core; + struct zephyr_domain_thread *dt; char thread_name[] = "ll_thread0"; k_tid_t thread; + int core = task->core; - tr_dbg(&ll_tr, "entry"); + tr_dbg(&ll_tr, "thread_init entry"); - /* domain work only needs registered once on each core */ - if (dt->handler) - return 0; + if (core >= CONFIG_CORE_COUNT) + return -EINVAL; - __ASSERT_NO_MSG(task->core == core); + dt = zephyr_domain->domain_thread + core; - dt->handler = handler; - dt->arg = arg; + /* thread only needs to be created once per core */ + if (dt->ll_thread) + return 0; + + dt->handler = NULL; + dt->arg = NULL; /* 10 is rather random, we better not accumulate 10 missed timer interrupts */ k_sem_init(dt->sem, 0, 10); thread_name[sizeof(thread_name) - 2] = '0' + core; + /* Allocate thread structure dynamically */ + dt->ll_thread = k_object_alloc(K_OBJ_THREAD); if (!dt->ll_thread) { - /* Allocate thread structure dynamically */ - dt->ll_thread = k_object_alloc(K_OBJ_THREAD); - if (!dt->ll_thread) { - tr_err(&ll_tr, "Failed to allocate thread object for core %d", core); - dt->handler = NULL; - dt->arg = NULL; - return -ENOMEM; - } + tr_err(&ll_tr, "Failed to allocate thread object for core %d", core); + return -ENOMEM; + } - thread = k_thread_create(dt->ll_thread, ll_sched_stack[core], ZEPHYR_LL_STACK_SIZE, - zephyr_domain_thread_fn, zephyr_domain, - INT_TO_POINTER(core), NULL, CONFIG_LL_THREAD_PRIORITY, - K_USER, K_FOREVER); + thread = k_thread_create(dt->ll_thread, ll_sched_stack[core], ZEPHYR_LL_STACK_SIZE, + zephyr_domain_thread_fn, zephyr_domain, + INT_TO_POINTER(core), NULL, CONFIG_LL_THREAD_PRIORITY, + K_USER, K_FOREVER); #ifdef CONFIG_SCHED_CPU_MASK - k_thread_cpu_mask_clear(thread); - k_thread_cpu_mask_enable(thread, core); + k_thread_cpu_mask_clear(thread); + k_thread_cpu_mask_enable(thread, core); #endif - k_thread_name_set(thread, thread_name); + k_thread_name_set(thread, thread_name); - k_mem_domain_add_thread(zephyr_ll_mem_domain(), thread); - k_thread_access_grant(thread, dt->sem, domain->lock, zephyr_domain->timer); - user_grant_dai_access_all(thread); - user_grant_dma_access_all(thread); - tr_dbg(&ll_tr, "granted LL access to thread %p (core %d)", thread, core); + k_mem_domain_add_thread(zephyr_ll_mem_domain(), thread); + k_thread_access_grant(thread, dt->sem, domain->lock, zephyr_domain->timer); + user_grant_dai_access_all(thread); + user_grant_dma_access_all(thread); + tr_dbg(&ll_tr, "granted LL access to thread %p (core %d)", thread, core); - k_thread_start(thread); - } + k_thread_start(thread); k_mutex_lock(domain->lock, K_FOREVER); if (!k_timer_user_data_get(zephyr_domain->timer)) { @@ -368,6 +371,43 @@ static int zephyr_domain_register_user(struct ll_schedule_domain *domain, return 0; } +/* + * User-space register: bookkeeping only. The privileged thread setup has + * already been done by domain_thread_init() called from kernel context. + */ +static int zephyr_domain_register_user(struct ll_schedule_domain *domain, + struct task *task, + void (*handler)(void *arg), void *arg) +{ + struct zephyr_domain *zephyr_domain = ll_sch_domain_get_pdata(domain); + struct zephyr_domain_thread *dt; + int core; + + tr_dbg(&ll_tr, "register_user entry"); + + if (task->core >= CONFIG_CORE_COUNT) + return -EINVAL; + + core = task->core; + dt = zephyr_domain->domain_thread + core; + + if (!dt->ll_thread) { + tr_err(&ll_tr, "domain_thread_init() not called for core %d", core); + return -EINVAL; + } + + __ASSERT_NO_MSG(!dt->handler || dt->handler == handler); + if (dt->handler) + return 0; + + dt->handler = handler; + dt->arg = arg; + + tr_info(&ll_tr, "task registered on core %d", core); + + return 0; +} + static int zephyr_domain_unregister_user(struct ll_schedule_domain *domain, struct task *task, uint32_t num_tasks) { @@ -382,30 +422,58 @@ static int zephyr_domain_unregister_user(struct ll_schedule_domain *domain, k_mutex_lock(domain->lock, K_FOREVER); - if (!atomic_read(&domain->total_num_tasks)) { - /* Disable the watchdog */ + zephyr_domain->domain_thread[core].handler = NULL; + + k_mutex_unlock(domain->lock); + + /* + * In this user thread implementation, the timer is left + * running until privileged domain_thread_free() is called + * to clean up resources. + */ + + tr_dbg(&ll_tr, "exit"); + + return 0; +} + +/* + * Free resources acquired by zephyr_domain_thread_init(). + * Stops the timer, aborts the scheduling thread and frees the thread object. + * Must be called from kernel context. + */ +static void zephyr_domain_thread_free(struct ll_schedule_domain *domain, + uint32_t num_tasks) +{ + struct zephyr_domain *zephyr_domain = ll_sch_domain_get_pdata(domain); + int core = cpu_get_id(); + struct zephyr_domain_thread *dt = zephyr_domain->domain_thread + core; + + tr_dbg(&ll_tr, "thread_free entry, core %d, num_tasks %u", core, num_tasks); + + /* Still tasks on other cores, only clean up this core's thread */ + k_mutex_lock(domain->lock, K_FOREVER); + + if (!num_tasks && !atomic_read(&domain->total_num_tasks)) { + /* Last task globally: stop the timer and watchdog */ watchdog_disable(core); k_timer_stop(zephyr_domain->timer); k_timer_user_data_set(zephyr_domain->timer, NULL); } - zephyr_domain->domain_thread[core].handler = NULL; + dt->handler = NULL; + dt->arg = NULL; k_mutex_unlock(domain->lock); - tr_info(&ll_tr, "domain->type %d domain->clk %d", - domain->type, domain->clk); - - /* Thread not removed here, only the timer is stopped. - * Thread object cleanup would require k_thread_abort() which cannot - * be safely called from this context. The thread remains allocated - * but dormant until next registration or system shutdown. - */ - - tr_dbg(&ll_tr, "exit"); + if (dt->ll_thread) { + k_thread_abort(dt->ll_thread); + k_object_free(dt->ll_thread); + dt->ll_thread = NULL; + } - return 0; + tr_info(&ll_tr, "thread_free done, core %d", core); } struct k_thread *zephyr_domain_thread_tid(struct ll_schedule_domain *domain) @@ -450,6 +518,8 @@ APP_TASK_DATA static const struct ll_schedule_domain_ops zephyr_domain_ops = { #ifdef CONFIG_SOF_USERSPACE_LL .domain_register = zephyr_domain_register_user, .domain_unregister = zephyr_domain_unregister_user, + .domain_thread_init = zephyr_domain_thread_init, + .domain_thread_free = zephyr_domain_thread_free, #else .domain_register = zephyr_domain_register, .domain_unregister = zephyr_domain_unregister, diff --git a/src/schedule/zephyr_ll.c b/src/schedule/zephyr_ll.c index 575a82d91dda..1c1717d30ac6 100644 --- a/src/schedule/zephyr_ll.c +++ b/src/schedule/zephyr_ll.c @@ -360,17 +360,7 @@ static int zephyr_ll_task_schedule_common(struct zephyr_ll *sch, struct task *ta ret = domain_register(sch->ll_domain, task, &schedule_ll_callback, sch); if (ret < 0) - tr_err(&ll_tr, "cannot register domain %d", - ret); - -#if CONFIG_SOF_USERSPACE_LL - k_thread_access_grant(zephyr_domain_thread_tid(sch->ll_domain), sch->lock); - - tr_dbg(&ll_tr, "granting access to lock %p for thread %p", sch->lock, - zephyr_domain_thread_tid(sch->ll_domain)); - tr_dbg(&ll_tr, "granting access to domain lock %p for thread %p", &sch->ll_domain->lock, - zephyr_domain_thread_tid(sch->ll_domain)); -#endif + tr_err(&ll_tr, "cannot register domain %d", ret); return 0; } @@ -509,8 +499,41 @@ static void zephyr_ll_scheduler_free(void *data, uint32_t flags) if (sch->n_tasks) tr_err(&ll_tr, "%u tasks are still active!", sch->n_tasks); + +#if CONFIG_SOF_USERSPACE_LL + domain_thread_free(sch->ll_domain, sch->n_tasks); +#endif } +#if CONFIG_SOF_USERSPACE_LL +struct k_thread *zephyr_ll_init_context(void *data, struct task *task) +{ + struct zephyr_ll *sch = data; + int ret; + + /* + * Use domain_thread_init() for privileged setup (thread creation, + * timer, access grants). domain_register() is now bookkeeping only + * and will be called later from user context when scheduling tasks. + */ + ret = domain_thread_init(sch->ll_domain, task); + if (ret < 0) { + tr_err(&ll_tr, "cannot init_context %d", ret); + return NULL; + } + + assert(!k_is_user_context()); + k_thread_access_grant(zephyr_domain_thread_tid(sch->ll_domain), sch->lock); + + tr_dbg(&ll_tr, "granting access to lock %p for thread %p", sch->lock, + zephyr_domain_thread_tid(sch->ll_domain)); + tr_dbg(&ll_tr, "granting access to domain lock %p for thread %p", &sch->ll_domain->lock, + zephyr_domain_thread_tid(sch->ll_domain)); + + return zephyr_domain_thread_tid(sch->ll_domain); +} +#endif + static const struct scheduler_ops zephyr_ll_ops = { .schedule_task = zephyr_ll_task_schedule, .schedule_task_before = zephyr_ll_task_schedule_before, @@ -518,6 +541,9 @@ static const struct scheduler_ops zephyr_ll_ops = { .schedule_task_free = zephyr_ll_task_free, .schedule_task_cancel = zephyr_ll_task_cancel, .scheduler_free = zephyr_ll_scheduler_free, +#if CONFIG_SOF_USERSPACE_LL + .scheduler_init_context = zephyr_ll_init_context, +#endif }; #if CONFIG_SOF_USERSPACE_LL