include/linux/kcsan.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * The Kernel Concurrency Sanitizer (KCSAN) infrastructure. Public interface and
   4  * data structures to set up runtime. See kcsan-checks.h for explicit checks and
   5  * modifiers. For more info please see Documentation/dev-tools/kcsan.rst.
   6  *
   7  * Copyright (C) 2019, Google LLC.
   8  */
   9
  10 #ifndef _LINUX_KCSAN_H
  11 #define _LINUX_KCSAN_H
  12
  13 #include <linux/kcsan-checks.h>
  14 #include <linux/types.h>
  15
  16 #ifdef CONFIG_KCSAN
  17
  18 /*
  19  * Context for each thread of execution: for tasks, this is stored in
  20  * task_struct, and interrupts access internal per-CPU storage.
  21  */
  22 struct kcsan_ctx {
  23         int disable_count; /* disable counter */
  24         int atomic_next; /* number of following atomic ops */
  25
  26         /*
  27          * We distinguish between: (a) nestable atomic regions that may contain
  28          * other nestable regions; and (b) flat atomic regions that do not keep
  29          * track of nesting. Both (a) and (b) are entirely independent of each
  30          * other, and a flat region may be started in a nestable region or
  31          * vice-versa.
  32          *
  33          * This is required because, for example, in the annotations for
  34          * seqlocks, we declare seqlock writer critical sections as (a) nestable
  35          * atomic regions, but reader critical sections as (b) flat atomic
  36          * regions, but have encountered cases where seqlock reader critical
  37          * sections are contained within writer critical sections (the opposite
  38          * may be possible, too).
  39          *
  40          * To support these cases, we independently track the depth of nesting
  41          * for (a), and whether the leaf level is flat for (b).
  42          */
  43         int atomic_nest_count;
  44         bool in_flat_atomic;
  45
  46         /*
  47          * Access mask for all accesses if non-zero.
  48          */
  49         unsigned long access_mask;
  50
  51         /* List of scoped accesses. */
  52         struct list_head scoped_accesses;
  53 };
  54
  55 /**
  56  * kcsan_init - initialize KCSAN runtime
  57  */
  58 void kcsan_init(void);
  59
  60 #else /* CONFIG_KCSAN */
  61
  62 static inline void kcsan_init(void)                     { }
  63
  64 #endif /* CONFIG_KCSAN */
  65
  66 #endif /* _LINUX_KCSAN_H */