linux-stable/include/linux/task_work.h
Sebastian Andrzej Siewior 466e4d801c task_work: Add TWA_NMI_CURRENT as an additional notify mode.
Adding task_work from NMI context requires the following:
- The kasan_record_aux_stack() is not NMU safe and must be avoided.
- Using TWA_RESUME is NMI safe. If the NMI occurs while the CPU is in
  userland then it will continue in userland and not invoke the `work'
  callback.

Add TWA_NMI_CURRENT as an additional notify mode. In this mode skip
kasan and use irq_work in hardirq-mode to for needed interrupt. Set
TIF_NOTIFY_RESUME within the irq_work callback due to k[ac]san
instrumentation in test_and_set_bit() which does not look NMI safe in
case of a report.

Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20240704170424.1466941-3-bigeasy@linutronix.de
2024-07-09 13:26:34 +02:00

44 lines
1.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_TASK_WORK_H
#define _LINUX_TASK_WORK_H
#include <linux/list.h>
#include <linux/sched.h>
typedef void (*task_work_func_t)(struct callback_head *);
static inline void
init_task_work(struct callback_head *twork, task_work_func_t func)
{
twork->func = func;
}
enum task_work_notify_mode {
TWA_NONE,
TWA_RESUME,
TWA_SIGNAL,
TWA_SIGNAL_NO_IPI,
TWA_NMI_CURRENT,
};
static inline bool task_work_pending(struct task_struct *task)
{
return READ_ONCE(task->task_works);
}
int task_work_add(struct task_struct *task, struct callback_head *twork,
enum task_work_notify_mode mode);
struct callback_head *task_work_cancel_match(struct task_struct *task,
bool (*match)(struct callback_head *, void *data), void *data);
struct callback_head *task_work_cancel_func(struct task_struct *, task_work_func_t);
bool task_work_cancel(struct task_struct *task, struct callback_head *cb);
void task_work_run(void);
static inline void exit_task_work(struct task_struct *task)
{
task_work_run();
}
#endif /* _LINUX_TASK_WORK_H */