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
kcsan_init(void)62 static inline void kcsan_init(void) { }
63
64 #endif /* CONFIG_KCSAN */
65
66 #endif /* _LINUX_KCSAN_H */
67