Line data    Source code

       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             : 
       8             : struct 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
      26             : extern struct static_key_false context_tracking_key;
      27             : DECLARE_PER_CPU(struct context_tracking, context_tracking);
      28             : 
      29             : static __always_inline bool context_tracking_enabled(void)
      30             : {
      31             :         return static_branch_unlikely(&context_tracking_key);
      32             : }
      33             : 
      34             : static __always_inline bool context_tracking_enabled_cpu(int cpu)
      35             : {
      36             :         return context_tracking_enabled() && per_cpu(context_tracking.active, cpu);
      37             : }
      38             : 
      39             : static inline bool context_tracking_enabled_this_cpu(void)
      40             : {
      41             :         return context_tracking_enabled() && __this_cpu_read(context_tracking.active);
      42             : }
      43             : 
      44             : static __always_inline bool context_tracking_in_user(void)
      45             : {
      46             :         return __this_cpu_read(context_tracking.state) == CONTEXT_USER;
      47             : }
      48             : #else
      49             : static inline bool context_tracking_in_user(void) { return false; }
      50      738501 : static inline bool context_tracking_enabled(void) { return false; }
      51             : static inline bool context_tracking_enabled_cpu(int cpu) { return false; }
      52             : static inline bool context_tracking_enabled_this_cpu(void) { return false; }
      53             : #endif /* CONFIG_CONTEXT_TRACKING */
      54             : 
      55             : #endif