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