Line data    Source code

       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           0 :         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           0 :         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           0 :         smp_mb__after_atomic();
      48           0 :         if (unlikely(task_work_pending(current)))
      49           0 :                 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 */