Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
1#ifndef _LINUX_CONTEXT_TRACKING_H
2#define _LINUX_CONTEXT_TRACKING_H
3
4#ifdef CONFIG_CONTEXT_TRACKING
5#include <linux/sched.h>
6#include <linux/percpu.h>
7
8struct context_tracking {
9 /*
10 * When active is false, probes are unset in order
11 * to minimize overhead: TIF flags are cleared
12 * and calls to user_enter/exit are ignored. This
13 * may be further optimized using static keys.
14 */
15 bool active;
16 enum {
17 IN_KERNEL = 0,
18 IN_USER,
19 } state;
20};
21
22DECLARE_PER_CPU(struct context_tracking, context_tracking);
23
24static inline bool context_tracking_in_user(void)
25{
26 return __this_cpu_read(context_tracking.state) == IN_USER;
27}
28
29static inline bool context_tracking_active(void)
30{
31 return __this_cpu_read(context_tracking.active);
32}
33
34extern void user_enter(void);
35extern void user_exit(void);
36extern void context_tracking_task_switch(struct task_struct *prev,
37 struct task_struct *next);
38#else
39static inline bool context_tracking_in_user(void) { return false; }
40static inline void user_enter(void) { }
41static inline void user_exit(void) { }
42static inline void context_tracking_task_switch(struct task_struct *prev,
43 struct task_struct *next) { }
44#endif /* !CONFIG_CONTEXT_TRACKING */
45
46#endif