1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_CONTEXT_TRACKING_STATE_H
3 #define _LINUX_CONTEXT_TRACKING_STATE_H
5 #include <linux/percpu.h>
6 #include <linux/static_key.h>
8 struct context_tracking {
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.
18 CONTEXT_DISABLED = -1, /* returned by ct_state() if unknown */
25 #ifdef CONFIG_CONTEXT_TRACKING
26 extern struct static_key_false context_tracking_key;
27 DECLARE_PER_CPU(struct context_tracking, context_tracking);
29 static __always_inline bool context_tracking_enabled(void)
31 return static_branch_unlikely(&context_tracking_key);
34 static __always_inline bool context_tracking_enabled_cpu(int cpu)
36 return context_tracking_enabled() && per_cpu(context_tracking.active, cpu);
39 static inline bool context_tracking_enabled_this_cpu(void)
41 return context_tracking_enabled() && __this_cpu_read(context_tracking.active);
44 static __always_inline bool context_tracking_in_user(void)
46 return __this_cpu_read(context_tracking.state) == CONTEXT_USER;
49 static inline bool context_tracking_in_user(void) { return false; }
50 static inline bool context_tracking_enabled(void) { return false; }
51 static inline bool context_tracking_enabled_cpu(int cpu) { return false; }
52 static inline bool context_tracking_enabled_this_cpu(void) { return false; }
53 #endif /* CONFIG_CONTEXT_TRACKING */