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 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 | */ |
67 | void kcsan_init(void); |
68 | |
69 | #else /* CONFIG_KCSAN */ |
70 | |
71 | static inline void kcsan_init(void) { } |
72 | |
73 | #endif /* CONFIG_KCSAN */ |
74 | |
75 | #endif /* _LINUX_KCSAN_H */ |
76 | |