LXR linux/include/linux/context_tracking

   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
   7struct 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                CONTEXT_KERNEL = 0,
  17                CONTEXT_USER,
  18                CONTEXT_GUEST,
  19        } state;
  20};
  21
  22#ifdef CONFIG_CONTEXT_TRACKING
  23extern struct static_key context_tracking_enabled;
  24DECLARE_PER_CPU(struct context_tracking, context_tracking);
  25
  26static inline bool context_tracking_is_enabled(void)
  27{
  28        return static_key_false(&context_tracking_enabled);
  29}
  30
  31static inline bool context_tracking_cpu_is_enabled(void)
  32{
  33        return __this_cpu_read(context_tracking.active);
  34}
  35
  36static inline bool context_tracking_in_user(void)
  37{
  38        return __this_cpu_read(context_tracking.state) == CONTEXT_USER;
  39}
  40#else
  41static inline bool context_tracking_in_user(void) { return false; }
  42static inline bool context_tracking_active(void) { return false; }
  43static inline bool context_tracking_is_enabled(void) { return false; }
  44static inline bool context_tracking_cpu_is_enabled(void) { return false; }
  45#endif /* CONFIG_CONTEXT_TRACKING */
  46
  47#endif
  48