46 lines
1.3 KiB
C
46 lines
1.3 KiB
C
|
// SPDX-License-Identifier: GPL-2.0-only
|
||
|
|
|
||
|
|
#include <linux/user-return-notifier.h>
|
||
|
|
#include <linux/percpu.h>
|
||
|
|
#include <linux/sched.h>
|
||
|
|
#include <linux/export.h>
|
||
|
|
|
||
|
|
static DEFINE_PER_CPU(struct hlist_head, return_notifier_list);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Request a notification when the current cpu returns to userspace. Must be
|
||
|
|
* called in atomic context. The notifier will also be called in atomic
|
||
|
|
* context.
|
||
|
|
*/
|
||
|
|
void user_return_notifier_register(struct user_return_notifier *urn)
|
||
|
|
{
|
||
|
|
set_tsk_thread_flag(current, TIF_USER_RETURN_NOTIFY);
|
||
|
|
hlist_add_head(&urn->link, this_cpu_ptr(&return_notifier_list));
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL_GPL(user_return_notifier_register);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Removes a registered user return notifier. Must be called from atomic
|
||
|
|
* context, and from the same cpu registration occurred in.
|
||
|
|
*/
|
||
|
|
void user_return_notifier_unregister(struct user_return_notifier *urn)
|
||
|
|
{
|
||
|
|
hlist_del(&urn->link);
|
||
|
|
if (hlist_empty(this_cpu_ptr(&return_notifier_list)))
|
||
|
|
clear_tsk_thread_flag(current, TIF_USER_RETURN_NOTIFY);
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL_GPL(user_return_notifier_unregister);
|
||
|
|
|
||
|
|
/* Calls registered user return notifiers */
|
||
|
|
void fire_user_return_notifiers(void)
|
||
|
|
{
|
||
|
|
struct user_return_notifier *urn;
|
||
|
|
struct hlist_node *tmp2;
|
||
|
|
struct hlist_head *head;
|
||
|
|
|
||
|
|
head = &get_cpu_var(return_notifier_list);
|
||
|
|
hlist_for_each_entry_safe(urn, tmp2, head, link)
|
||
|
|
urn->on_user_return(urn);
|
||
|
|
put_cpu_var(return_notifier_list);
|
||
|
|
}
|