From 7a69e97ba42a93e33dccfe715a8522754117a715 Mon Sep 17 00:00:00 2001 From: Heinrich Schuchardt Date: Wed, 5 Jun 2019 21:00:39 +0200 Subject: [PATCH] efi_loader: implement event queue Up to now we have only been using a flag queued for events. But this does not satisfy the requirements of the UEFI spec. Events must be notified in the sequence of decreasing TPL level and within a TPL level in the sequence of signaling. Implement a queue for signaled events. Signed-off-by: Heinrich Schuchardt --- include/efi_loader.h | 4 +- lib/efi_loader/efi_boottime.c | 94 +++++++++++++++++++++++++---------- 2 files changed, 70 insertions(+), 28 deletions(-) diff --git a/include/efi_loader.h b/include/efi_loader.h index 8a3f8fe03d..f0e1313f93 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -256,6 +256,7 @@ struct efi_loaded_image_obj { * struct efi_event * * @link: Link to list of all events + * @queue_link: Link to the list of queued events * @type: Type of event, see efi_create_event * @notify_tpl: Task priority level of notifications * @nofify_function: Function to call when the event is triggered @@ -264,11 +265,11 @@ struct efi_loaded_image_obj { * @trigger_time: Period of the timer * @trigger_next: Next time to trigger the timer * @trigger_type: Type of timer, see efi_set_timer - * @is_queued: The notification function is queued * @is_signaled: The event occurred. The event is in the signaled state. */ struct efi_event { struct list_head link; + struct list_head queue_link; uint32_t type; efi_uintn_t notify_tpl; void (EFIAPI *notify_function)(struct efi_event *event, void *context); @@ -277,7 +278,6 @@ struct efi_event { u64 trigger_next; u64 trigger_time; enum efi_timer_delay trigger_type; - bool is_queued; bool is_signaled; }; diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c index c146b47128..fa01bbda70 100644 --- a/lib/efi_loader/efi_boottime.c +++ b/lib/efi_loader/efi_boottime.c @@ -27,6 +27,9 @@ LIST_HEAD(efi_obj_list); /* List of all events */ LIST_HEAD(efi_events); +/* List of queued events */ +LIST_HEAD(efi_event_queue); + /* Flag to disable timer activity in ExitBootServices() */ static bool timers_enabled = true; @@ -163,6 +166,44 @@ const char *__efi_nesting_dec(void) return indent_string(--nesting_level); } +/** + * efi_event_is_queued() - check if an event is queued + * + * @event: event + * Return: true if event is queued + */ +static bool efi_event_is_queued(struct efi_event *event) +{ + return !!event->queue_link.next; +} + +/** + * efi_process_event_queue() - process event queue + */ +static void efi_process_event_queue(void) +{ + while (!list_empty(&efi_event_queue)) { + struct efi_event *event; + efi_uintn_t old_tpl; + + event = list_first_entry(&efi_event_queue, struct efi_event, + queue_link); + if (efi_tpl >= event->notify_tpl) + return; + list_del(&event->queue_link); + event->queue_link.next = NULL; + event->queue_link.prev = NULL; + /* Events must be executed at the event's TPL */ + old_tpl = efi_tpl; + efi_tpl = event->notify_tpl; + EFI_CALL_VOID(event->notify_function(event, + event->notify_context)); + efi_tpl = old_tpl; + if (event->type == EVT_NOTIFY_SIGNAL) + event->is_signaled = 0; + } +} + /** * efi_queue_event() - queue an EFI event * @event: event to signal @@ -170,25 +211,31 @@ const char *__efi_nesting_dec(void) * This function queues the notification function of the event for future * execution. * - * The notification function is called if the task priority level of the event - * is higher than the current task priority level. - * - * For the SignalEvent service see efi_signal_event_ext. - * */ static void efi_queue_event(struct efi_event *event) { - if (event->notify_function) { - event->is_queued = true; - /* Check TPL */ - if (efi_tpl >= event->notify_tpl) - return; - event->is_queued = false; - EFI_CALL_VOID(event->notify_function(event, - event->notify_context)); - } else { - event->is_queued = false; + struct efi_event *item = NULL; + + if (!event->notify_function) + return; + + if (!efi_event_is_queued(event)) { + /* + * Events must be notified in order of decreasing task priority + * level. Insert the new event accordingly. + */ + list_for_each_entry(item, &efi_event_queue, queue_link) { + if (item->notify_tpl < event->notify_tpl) { + list_add_tail(&event->queue_link, + &item->queue_link); + event = NULL; + break; + } + } + if (event) + list_add_tail(&event->queue_link, &efi_event_queue); } + efi_process_event_queue(); } /** @@ -237,20 +284,15 @@ void efi_signal_event(struct efi_event *event) if (evt->is_signaled) continue; evt->is_signaled = true; - if (evt->type & EVT_NOTIFY_SIGNAL && - evt->notify_function) - evt->is_queued = true; } list_for_each_entry(evt, &efi_events, link) { if (!evt->group || guidcmp(evt->group, event->group)) continue; - if (evt->is_queued) - efi_queue_event(evt); + efi_queue_event(evt); } } else { event->is_signaled = true; - if (event->type & EVT_NOTIFY_SIGNAL) - efi_queue_event(event); + efi_queue_event(event); } } @@ -640,8 +682,6 @@ efi_status_t efi_create_event(uint32_t type, efi_uintn_t notify_tpl, evt->group = group; /* Disable timers on boot up */ evt->trigger_next = -1ULL; - evt->is_queued = false; - evt->is_signaled = false; list_add_tail(&evt->link, &efi_events); *event = evt; return EFI_SUCCESS; @@ -736,8 +776,6 @@ void efi_timer_check(void) u64 now = timer_get_us(); list_for_each_entry(evt, &efi_events, link) { - if (evt->is_queued) - efi_queue_event(evt); if (!timers_enabled) continue; if (!(evt->type & EVT_TIMER) || now < evt->trigger_next) @@ -755,6 +793,7 @@ void efi_timer_check(void) evt->is_signaled = false; efi_signal_event(evt); } + efi_process_event_queue(); WATCHDOG_RESET(); } @@ -938,6 +977,9 @@ static efi_status_t EFIAPI efi_close_event(struct efi_event *event) free(item); } } + /* Remove event from queue */ + if (efi_event_is_queued(event)) + list_del(&event->queue_link); list_del(&event->link); free(event); -- 2.25.1