Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux...
[firefly-linux-kernel-4.4.55.git] / include / linux / context_tracking_state.h
1 #ifndef _LINUX_CONTEXT_TRACKING_STATE_H
2 #define _LINUX_CONTEXT_TRACKING_STATE_H
3
4 #include <linux/percpu.h>
5 #include <linux/static_key.h>
6
7 struct context_tracking {
8         /*
9          * When active is false, probes are unset in order
10          * to minimize overhead: TIF flags are cleared
11          * and calls to user_enter/exit are ignored. This
12          * may be further optimized using static keys.
13          */
14         bool active;
15         enum ctx_state {
16                 IN_KERNEL = 0,
17                 IN_USER,
18         } state;
19 };
20
21 #ifdef CONFIG_CONTEXT_TRACKING
22 extern struct static_key context_tracking_enabled;
23 DECLARE_PER_CPU(struct context_tracking, context_tracking);
24
25 static inline bool context_tracking_is_enabled(void)
26 {
27         return static_key_false(&context_tracking_enabled);
28 }
29
30 static inline bool context_tracking_cpu_is_enabled(void)
31 {
32         return __this_cpu_read(context_tracking.active);
33 }
34
35 static inline bool context_tracking_in_user(void)
36 {
37         return __this_cpu_read(context_tracking.state) == IN_USER;
38 }
39 #else
40 static inline bool context_tracking_in_user(void) { return false; }
41 static inline bool context_tracking_active(void) { return false; }
42 #endif /* CONFIG_CONTEXT_TRACKING */
43
44 #endif