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        int recursion;
  16        enum ctx_state {
  17                CONTEXT_DISABLED = -1,  /* returned by ct_state() if unknown */
  18                CONTEXT_KERNEL = 0,
  19                CONTEXT_USER,
  20                CONTEXT_GUEST,
  21        } state;
  22};
  23
  24#ifdef CONFIG_CONTEXT_TRACKING
  25extern struct static_key_false context_tracking_enabled;
  26DECLARE_PER_CPU(struct context_tracking, context_tracking);
  27
  28static inline bool context_tracking_is_enabled(void)
  29{
  30        return static_branch_unlikely(&context_tracking_enabled);
  31}
  32
  33static inline bool context_tracking_cpu_is_enabled(void)
  34{
  35        return __this_cpu_read(context_tracking.active);
  36}
  37
  38static inline bool context_tracking_in_user(void)
  39{
  40        return __this_cpu_read(context_tracking.state) == CONTEXT_USER;
  41}
  42#else
  43static inline bool context_tracking_in_user(void) { return false; }
  44static inline bool context_tracking_active(void) { return false; }
  45static inline bool context_tracking_is_enabled(void) { return false; }
  46static inline bool context_tracking_cpu_is_enabled(void) { return false; }
  47#endif /* CONFIG_CONTEXT_TRACKING */
  48
  49#endif
  50