diff options
Diffstat (limited to 'include/linux/resume_user_mode.h')
-rw-r--r-- | include/linux/resume_user_mode.h | 64 |
1 files changed, 64 insertions, 0 deletions
diff --git a/include/linux/resume_user_mode.h b/include/linux/resume_user_mode.h new file mode 100644 index 000000000000..285189454449 --- /dev/null +++ b/include/linux/resume_user_mode.h @@ -0,0 +1,64 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef LINUX_RESUME_USER_MODE_H +#define LINUX_RESUME_USER_MODE_H + +#include <linux/sched.h> +#include <linux/task_work.h> +#include <linux/memcontrol.h> +#include <linux/blk-cgroup.h> + +/** + * set_notify_resume - cause resume_user_mode_work() to be called + * @task: task that will call resume_user_mode_work() + * + * Calling this arranges that @task will call resume_user_mode_work() + * before returning to user mode. If it's already running in user mode, + * it will enter the kernel and call resume_user_mode_work() soon. + * If it's blocked, it will not be woken. + */ +static inline void set_notify_resume(struct task_struct *task) +{ + if (!test_and_set_tsk_thread_flag(task, TIF_NOTIFY_RESUME)) + kick_process(task); +} + + +/** + * resume_user_mode_work - Perform work before returning to user mode + * @regs: user-mode registers of @current task + * + * This is called when %TIF_NOTIFY_RESUME has been set. Now we are + * about to return to user mode, and the user state in @regs can be + * inspected or adjusted. The caller in arch code has cleared + * %TIF_NOTIFY_RESUME before the call. If the flag gets set again + * asynchronously, this will be called again before we return to + * user mode. + * + * Called without locks. + */ +static inline void resume_user_mode_work(struct pt_regs *regs) +{ + clear_thread_flag(TIF_NOTIFY_RESUME); + /* + * This barrier pairs with task_work_add()->set_notify_resume() after + * hlist_add_head(task->task_works); + */ + smp_mb__after_atomic(); + if (unlikely(task_work_pending(current))) + task_work_run(); + +#ifdef CONFIG_KEYS_REQUEST_CACHE + if (unlikely(current->cached_requested_key)) { + key_put(current->cached_requested_key); + current->cached_requested_key = NULL; + } +#endif + + mem_cgroup_handle_over_high(); + blkcg_maybe_throttle_current(); + + rseq_handle_notify_resume(NULL, regs); +} + +#endif /* LINUX_RESUME_USER_MODE_H */ |