Commit | Line | Data |
---|---|---|
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 FW |
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; | |
6c1e0256 | 16 | enum ctx_state { |
95a79fd4 FW |
17 | IN_KERNEL = 0, |
18 | IN_USER, | |
19 | } state; | |
20 | }; | |
21 | ||
6c1e0256 | 22 | #ifdef CONFIG_CONTEXT_TRACKING |
95a79fd4 FW |
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 | 37 | |
6c1e0256 | 38 | static inline enum ctx_state exception_enter(void) |
56dd9470 | 39 | { |
6c1e0256 FW |
40 | enum ctx_state prev_ctx; |
41 | ||
42 | prev_ctx = this_cpu_read(context_tracking.state); | |
56dd9470 | 43 | user_exit(); |
6c1e0256 FW |
44 | |
45 | return prev_ctx; | |
56dd9470 FW |
46 | } |
47 | ||
6c1e0256 | 48 | static inline void exception_exit(enum ctx_state prev_ctx) |
56dd9470 | 49 | { |
6c1e0256 | 50 | if (prev_ctx == IN_USER) |
56dd9470 FW |
51 | user_enter(); |
52 | } | |
53 | ||
91d1aa43 FW |
54 | extern void context_tracking_task_switch(struct task_struct *prev, |
55 | struct task_struct *next); | |
56 | #else | |
95a79fd4 | 57 | static inline bool context_tracking_in_user(void) { return false; } |
91d1aa43 FW |
58 | static inline void user_enter(void) { } |
59 | static inline void user_exit(void) { } | |
6c1e0256 FW |
60 | static inline enum ctx_state exception_enter(void) { return 0; } |
61 | static inline void exception_exit(enum ctx_state prev_ctx) { } | |
91d1aa43 FW |
62 | static inline void context_tracking_task_switch(struct task_struct *prev, |
63 | struct task_struct *next) { } | |
64 | #endif /* !CONFIG_CONTEXT_TRACKING */ | |
65 | ||
66 | #endif |