| 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 */ |