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 */ set_notify_resume(struct task_struct * task)20static 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 */ resume_user_mode_work(struct pt_regs * regs)40static 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(GFP_KERNEL); 59 blkcg_maybe_throttle_current(); 60 61 rseq_handle_notify_resume(NULL, regs); 62 } 63 64 #endif /* LINUX_RESUME_USER_MODE_H */ 65