LXR linux/include/linux/context_tracking

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _LINUX_CONTEXT_TRACKING_STATE_H
   3#define _LINUX_CONTEXT_TRACKING_STATE_H
   4
   5#include <linux/percpu.h>
   6#include <linux/static_key.h>
   7
   8struct context_tracking {
   9        /*
  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.
  14         */
  15        bool active;
  16        int recursion;
  17        enum ctx_state {
  18                CONTEXT_DISABLED = -1,  /* returned by ct_state() if unknown */
  19                CONTEXT_KERNEL = 0,
  20                CONTEXT_USER,
  21                CONTEXT_GUEST,
  22        } state;
  23};
  24
  25#ifdef CONFIG_CONTEXT_TRACKING
  26extern struct static_key_false context_tracking_enabled;
  27DECLARE_PER_CPU(struct context_tracking, context_tracking);
  28
  29static inline bool context_tracking_is_enabled(void)
  30{
  31        return static_branch_unlikely(&context_tracking_enabled);
  32}
  33
  34static inline bool context_tracking_cpu_is_enabled(void)
  35{
  36        return __this_cpu_read(context_tracking.active);
  37}
  38
  39static inline bool context_tracking_in_user(void)
  40{
  41        return __this_cpu_read(context_tracking.state) == CONTEXT_USER;
  42}
  43#else
  44static inline bool context_tracking_in_user(void) { return false; }
  45static inline bool context_tracking_active(void) { return false; }
  46static inline bool context_tracking_is_enabled(void) { return false; }
  47static inline bool context_tracking_cpu_is_enabled(void) { return false; }
  48#endif /* CONFIG_CONTEXT_TRACKING */
  49
  50#endif
  51