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91d1aa43 FW |
1 | #ifndef _LINUX_CONTEXT_TRACKING_H |
2 | #define _LINUX_CONTEXT_TRACKING_H | |
3 | ||
4 | #ifdef CONFIG_CONTEXT_TRACKING | |
5 | #include <linux/sched.h> | |
95a79fd4 FW |
6 | #include <linux/percpu.h> |
7 | ||
8 | struct 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 | ||
22 | DECLARE_PER_CPU(struct context_tracking, context_tracking); | |
23 | ||
24 | static inline bool context_tracking_in_user(void) | |
25 | { | |
26 | return __this_cpu_read(context_tracking.state) == IN_USER; | |
27 | } | |
28 | ||
29 | static inline bool context_tracking_active(void) | |
30 | { | |
31 | return __this_cpu_read(context_tracking.active); | |
32 | } | |
91d1aa43 FW |
33 | |
34 | extern void user_enter(void); | |
35 | extern void user_exit(void); | |
36 | extern void context_tracking_task_switch(struct task_struct *prev, | |
37 | struct task_struct *next); | |
38 | #else | |
95a79fd4 | 39 | static inline bool context_tracking_in_user(void) { return false; } |
91d1aa43 FW |
40 | static inline void user_enter(void) { } |
41 | static inline void user_exit(void) { } | |
42 | static inline void context_tracking_task_switch(struct task_struct *prev, | |
43 | struct task_struct *next) { } | |
44 | #endif /* !CONFIG_CONTEXT_TRACKING */ | |
45 | ||
46 | #endif |