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 45