[U-Boot] [PATCH 2/2] efi_loader: implement event queue
Heinrich Schuchardt
xypron.glpk at gmx.de
Mon Jun 10 21:10:04 UTC 2019
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 <xypron.glpk at gmx.de>
---
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);
--
2.20.1
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