1/* SPDX-License-Identifier: GPL-2.0-only */
2
3#ifndef LINUX_RESUME_USER_MODE_H
4#define LINUX_RESUME_USER_MODE_H
5
6#include <linux/sched.h>
7#include <linux/task_work.h>
8#include <linux/memcontrol.h>
9#include <linux/rseq.h>
10#include <linux/blk-cgroup.h>
11
12/**
13 * set_notify_resume - cause resume_user_mode_work() to be called
14 * @task:		task that will call resume_user_mode_work()
15 *
16 * Calling this arranges that @task will call resume_user_mode_work()
17 * before returning to user mode.  If it's already running in user mode,
18 * it will enter the kernel and call resume_user_mode_work() soon.
19 * If it's blocked, it will not be woken.
20 */
21static inline void set_notify_resume(struct task_struct *task)
22{
23	if (!test_and_set_tsk_thread_flag(task, TIF_NOTIFY_RESUME))
24		kick_process(task);
25}
26
27
28/**
29 * resume_user_mode_work - Perform work before returning to user mode
30 * @regs:		user-mode registers of @current task
31 *
32 * This is called when %TIF_NOTIFY_RESUME has been set.  Now we are
33 * about to return to user mode, and the user state in @regs can be
34 * inspected or adjusted.  The caller in arch code has cleared
35 * %TIF_NOTIFY_RESUME before the call.  If the flag gets set again
36 * asynchronously, this will be called again before we return to
37 * user mode.
38 *
39 * Called without locks.
40 */
41static inline void resume_user_mode_work(struct pt_regs *regs)
42{
43	clear_thread_flag(TIF_NOTIFY_RESUME);
44	/*
45	 * This barrier pairs with task_work_add()->set_notify_resume() after
46	 * hlist_add_head(task->task_works);
47	 */
48	smp_mb__after_atomic();
49	if (unlikely(task_work_pending(current)))
50		task_work_run();
51
52#ifdef CONFIG_KEYS_REQUEST_CACHE
53	if (unlikely(current->cached_requested_key)) {
54		key_put(current->cached_requested_key);
55		current->cached_requested_key = NULL;
56	}
57#endif
58
59	mem_cgroup_handle_over_high(GFP_KERNEL);
60	blkcg_maybe_throttle_current();
61
62	rseq_handle_notify_resume(NULL, regs);
63}
64
65#endif /* LINUX_RESUME_USER_MODE_H */
66