context_tracking_state.h 1.6 KB

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  1. /* SPDX-License-Identifier: GPL-2.0 */
  2. #ifndef _LINUX_CONTEXT_TRACKING_STATE_H
  3. #define _LINUX_CONTEXT_TRACKING_STATE_H
  4. #include <linux/percpu.h>
  5. #include <linux/static_key.h>
  6. struct context_tracking {
  7. /*
  8. * When active is false, probes are unset in order
  9. * to minimize overhead: TIF flags are cleared
  10. * and calls to user_enter/exit are ignored. This
  11. * may be further optimized using static keys.
  12. */
  13. bool active;
  14. int recursion;
  15. enum ctx_state {
  16. CONTEXT_DISABLED = -1, /* returned by ct_state() if unknown */
  17. CONTEXT_KERNEL = 0,
  18. CONTEXT_USER,
  19. CONTEXT_GUEST,
  20. } state;
  21. };
  22. #ifdef CONFIG_CONTEXT_TRACKING
  23. extern struct static_key_false context_tracking_key;
  24. DECLARE_PER_CPU(struct context_tracking, context_tracking);
  25. static __always_inline bool context_tracking_enabled(void)
  26. {
  27. return static_branch_unlikely(&context_tracking_key);
  28. }
  29. static __always_inline bool context_tracking_enabled_cpu(int cpu)
  30. {
  31. return context_tracking_enabled() && per_cpu(context_tracking.active, cpu);
  32. }
  33. static inline bool context_tracking_enabled_this_cpu(void)
  34. {
  35. return context_tracking_enabled() && __this_cpu_read(context_tracking.active);
  36. }
  37. static __always_inline bool context_tracking_in_user(void)
  38. {
  39. return __this_cpu_read(context_tracking.state) == CONTEXT_USER;
  40. }
  41. #else
  42. static inline bool context_tracking_in_user(void) { return false; }
  43. static inline bool context_tracking_enabled(void) { return false; }
  44. static inline bool context_tracking_enabled_cpu(int cpu) { return false; }
  45. static inline bool context_tracking_enabled_this_cpu(void) { return false; }
  46. #endif /* CONFIG_CONTEXT_TRACKING */
  47. #endif