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91d1aa43 FW |
1 | #ifndef _LINUX_CONTEXT_TRACKING_H |
2 | #define _LINUX_CONTEXT_TRACKING_H | |
3 | ||
91d1aa43 | 4 | #include <linux/sched.h> |
95a79fd4 | 5 | #include <linux/percpu.h> |
56dd9470 | 6 | #include <asm/ptrace.h> |
95a79fd4 | 7 | |
56dd9470 | 8 | #ifdef CONFIG_CONTEXT_TRACKING |
95a79fd4 FW |
9 | struct context_tracking { |
10 | /* | |
11 | * When active is false, probes are unset in order | |
12 | * to minimize overhead: TIF flags are cleared | |
13 | * and calls to user_enter/exit are ignored. This | |
14 | * may be further optimized using static keys. | |
15 | */ | |
16 | bool active; | |
17 | enum { | |
18 | IN_KERNEL = 0, | |
19 | IN_USER, | |
20 | } state; | |
21 | }; | |
22 | ||
23 | DECLARE_PER_CPU(struct context_tracking, context_tracking); | |
24 | ||
25 | static inline bool context_tracking_in_user(void) | |
26 | { | |
27 | return __this_cpu_read(context_tracking.state) == IN_USER; | |
28 | } | |
29 | ||
30 | static inline bool context_tracking_active(void) | |
31 | { | |
32 | return __this_cpu_read(context_tracking.active); | |
33 | } | |
91d1aa43 FW |
34 | |
35 | extern void user_enter(void); | |
36 | extern void user_exit(void); | |
56dd9470 FW |
37 | |
38 | static inline void exception_enter(struct pt_regs *regs) | |
39 | { | |
40 | user_exit(); | |
41 | } | |
42 | ||
43 | static inline void exception_exit(struct pt_regs *regs) | |
44 | { | |
45 | if (user_mode(regs)) | |
46 | user_enter(); | |
47 | } | |
48 | ||
91d1aa43 FW |
49 | extern void context_tracking_task_switch(struct task_struct *prev, |
50 | struct task_struct *next); | |
51 | #else | |
95a79fd4 | 52 | static inline bool context_tracking_in_user(void) { return false; } |
91d1aa43 FW |
53 | static inline void user_enter(void) { } |
54 | static inline void user_exit(void) { } | |
56dd9470 FW |
55 | static inline void exception_enter(struct pt_regs *regs) { } |
56 | static inline void exception_exit(struct pt_regs *regs) { } | |
91d1aa43 FW |
57 | static inline void context_tracking_task_switch(struct task_struct *prev, |
58 | struct task_struct *next) { } | |
59 | #endif /* !CONFIG_CONTEXT_TRACKING */ | |
60 | ||
61 | #endif |