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