From: James Morse james.morse@arm.com
[ Upstream commit 6ded0b61cf638bf9f8efe60ab8ba23db60ea9763 ]
SDEI has private events that must be registered on each CPU. When CPUs come and go they must re-register and re-enable their private events. Each event has flags to indicate whether this should happen to protect against an event being registered on a CPU coming online, while all the others are unregistering the event.
These flags are protected by the sdei_list_lock spinlock, because the cpuhp callbacks can't take the mutex.
Hibernate needs to unregister all events, but keep the in-memory re-register and re-enable as they are. sdei_unregister_shared() takes the spinlock to walk the list, then calls _sdei_event_unregister() on each shared event. _sdei_event_unregister() tries to take the same spinlock to update re-register and re-enable. This doesn't go so well.
Push the re-register and re-enable updates out to their callers. sdei_unregister_shared() doesn't want these values updated, so doesn't need to do anything.
This also fixes shared events getting lost over hibernate as this path made them look unregistered.
Fixes: da351827240e ("firmware: arm_sdei: Add support for CPU and system power states") Reported-by: Liguang Zhang zhangliguang@linux.alibaba.com Signed-off-by: James Morse james.morse@arm.com Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/firmware/arm_sdei.c | 32 +++++++++++++++----------------- 1 file changed, 15 insertions(+), 17 deletions(-)
diff --git a/drivers/firmware/arm_sdei.c b/drivers/firmware/arm_sdei.c index 5d6769b..2b5f277 100644 --- a/drivers/firmware/arm_sdei.c +++ b/drivers/firmware/arm_sdei.c @@ -512,11 +512,6 @@ static int _sdei_event_unregister(struct sdei_event *event) { lockdep_assert_held(&sdei_events_lock);
- spin_lock(&sdei_list_lock); - event->reregister = false; - event->reenable = false; - spin_unlock(&sdei_list_lock); - if (event->type == SDEI_EVENT_TYPE_SHARED) return sdei_api_event_unregister(event->event_num);
@@ -539,6 +534,11 @@ int sdei_event_unregister(u32 event_num) break; }
+ spin_lock(&sdei_list_lock); + event->reregister = false; + event->reenable = false; + spin_unlock(&sdei_list_lock); + err = _sdei_event_unregister(event); if (err) break; @@ -606,26 +606,15 @@ static int _sdei_event_register(struct sdei_event *event)
lockdep_assert_held(&sdei_events_lock);
- spin_lock(&sdei_list_lock); - event->reregister = true; - spin_unlock(&sdei_list_lock); - if (event->type == SDEI_EVENT_TYPE_SHARED) return sdei_api_event_register(event->event_num, sdei_entry_point, event->registered, SDEI_EVENT_REGISTER_RM_ANY, 0);
- err = sdei_do_cross_call(_local_event_register, event); - if (err) { - spin_lock(&sdei_list_lock); - event->reregister = false; - event->reenable = false; - spin_unlock(&sdei_list_lock); - + if (err) sdei_do_cross_call(_local_event_unregister, event); - }
return err; } @@ -653,8 +642,17 @@ int sdei_event_register(u32 event_num, sdei_event_callback *cb, void *arg) break; }
+ spin_lock(&sdei_list_lock); + event->reregister = true; + spin_unlock(&sdei_list_lock); + err = _sdei_event_register(event); if (err) { + spin_lock(&sdei_list_lock); + event->reregister = false; + event->reenable = false; + spin_unlock(&sdei_list_lock); + sdei_event_destroy(event); pr_warn("Failed to register event %u: %d\n", event_num, err);