LXR linux/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 */
  22struct kcsan_ctx {
  23        int disable_count; /* disable counter */
  24        int disable_scoped; /* disable scoped access counter */
  25        int atomic_next; /* number of following atomic ops */
  26
  27        /*
  28         * We distinguish between: (a) nestable atomic regions that may contain
  29         * other nestable regions; and (b) flat atomic regions that do not keep
  30         * track of nesting. Both (a) and (b) are entirely independent of each
  31         * other, and a flat region may be started in a nestable region or
  32         * vice-versa.
  33         *
  34         * This is required because, for example, in the annotations for
  35         * seqlocks, we declare seqlock writer critical sections as (a) nestable
  36         * atomic regions, but reader critical sections as (b) flat atomic
  37         * regions, but have encountered cases where seqlock reader critical
  38         * sections are contained within writer critical sections (the opposite
  39         * may be possible, too).
  40         *
  41         * To support these cases, we independently track the depth of nesting
  42         * for (a), and whether the leaf level is flat for (b).
  43         */
  44        int atomic_nest_count;
  45        bool in_flat_atomic;
  46
  47        /*
  48         * Access mask for all accesses if non-zero.
  49         */
  50        unsigned long access_mask;
  51
  52        /* List of scoped accesses; likely to be empty. */
  53        struct list_head scoped_accesses;
  54
  55#ifdef CONFIG_KCSAN_WEAK_MEMORY
  56        /*
  57         * Scoped access for modeling access reordering to detect missing memory
  58         * barriers; only keep 1 to keep fast-path complexity manageable.
  59         */
  60        struct kcsan_scoped_access reorder_access;
  61#endif
  62};
  63
  64/**
  65 * kcsan_init - initialize KCSAN runtime
  66 */
  67void kcsan_init(void);
  68
  69#else /* CONFIG_KCSAN */
  70
  71static inline void kcsan_init(void)                     { }
  72
  73#endif /* CONFIG_KCSAN */
  74
  75#endif /* _LINUX_KCSAN_H */
  76