| 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 | */ |
| 21 | static inline void set_notify_resume(struct task_struct *task) |
| 22 | { |
| 23 | if (!test_and_set_tsk_thread_flag(tsk: task, TIF_NOTIFY_RESUME)) |
| 24 | kick_process(tsk: 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 | */ |
| 41 | static 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_slowpath(regs); |
| 63 | } |
| 64 | |
| 65 | #endif /* LINUX_RESUME_USER_MODE_H */ |
| 66 |