1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | /* |
3 | * The Kernel Concurrency Sanitizer (KCSAN) infrastructure. For more info please |
4 | * see Documentation/dev-tools/kcsan.rst. |
5 | * |
6 | * Copyright (C) 2019, Google LLC. |
7 | */ |
8 | |
9 | #ifndef _KERNEL_KCSAN_KCSAN_H |
10 | #define _KERNEL_KCSAN_KCSAN_H |
11 | |
12 | #include <linux/atomic.h> |
13 | #include <linux/kcsan.h> |
14 | #include <linux/sched.h> |
15 | |
16 | /* The number of adjacent watchpoints to check. */ |
17 | #define KCSAN_CHECK_ADJACENT 1 |
18 | #define NUM_SLOTS (1 + 2*KCSAN_CHECK_ADJACENT) |
19 | |
20 | extern unsigned int kcsan_udelay_task; |
21 | extern unsigned int kcsan_udelay_interrupt; |
22 | |
23 | /* |
24 | * Globally enable and disable KCSAN. |
25 | */ |
26 | extern bool kcsan_enabled; |
27 | |
28 | /* |
29 | * Save/restore IRQ flags state trace dirtied by KCSAN. |
30 | */ |
31 | void kcsan_save_irqtrace(struct task_struct *task); |
32 | void kcsan_restore_irqtrace(struct task_struct *task); |
33 | |
34 | /* |
35 | * Statistics counters displayed via debugfs; should only be modified in |
36 | * slow-paths. |
37 | */ |
38 | enum kcsan_counter_id { |
39 | /* |
40 | * Number of watchpoints currently in use. |
41 | */ |
42 | KCSAN_COUNTER_USED_WATCHPOINTS, |
43 | |
44 | /* |
45 | * Total number of watchpoints set up. |
46 | */ |
47 | KCSAN_COUNTER_SETUP_WATCHPOINTS, |
48 | |
49 | /* |
50 | * Total number of data races. |
51 | */ |
52 | KCSAN_COUNTER_DATA_RACES, |
53 | |
54 | /* |
55 | * Total number of ASSERT failures due to races. If the observed race is |
56 | * due to two conflicting ASSERT type accesses, then both will be |
57 | * counted. |
58 | */ |
59 | KCSAN_COUNTER_ASSERT_FAILURES, |
60 | |
61 | /* |
62 | * Number of times no watchpoints were available. |
63 | */ |
64 | KCSAN_COUNTER_NO_CAPACITY, |
65 | |
66 | /* |
67 | * A thread checking a watchpoint raced with another checking thread; |
68 | * only one will be reported. |
69 | */ |
70 | KCSAN_COUNTER_REPORT_RACES, |
71 | |
72 | /* |
73 | * Observed data value change, but writer thread unknown. |
74 | */ |
75 | KCSAN_COUNTER_RACES_UNKNOWN_ORIGIN, |
76 | |
77 | /* |
78 | * The access cannot be encoded to a valid watchpoint. |
79 | */ |
80 | KCSAN_COUNTER_UNENCODABLE_ACCESSES, |
81 | |
82 | /* |
83 | * Watchpoint encoding caused a watchpoint to fire on mismatching |
84 | * accesses. |
85 | */ |
86 | KCSAN_COUNTER_ENCODING_FALSE_POSITIVES, |
87 | |
88 | KCSAN_COUNTER_COUNT, /* number of counters */ |
89 | }; |
90 | extern atomic_long_t kcsan_counters[KCSAN_COUNTER_COUNT]; |
91 | |
92 | /* |
93 | * Returns true if data races in the function symbol that maps to func_addr |
94 | * (offsets are ignored) should *not* be reported. |
95 | */ |
96 | extern bool kcsan_skip_report_debugfs(unsigned long func_addr); |
97 | |
98 | /* |
99 | * Value-change states. |
100 | */ |
101 | enum kcsan_value_change { |
102 | /* |
103 | * Did not observe a value-change, however, it is valid to report the |
104 | * race, depending on preferences. |
105 | */ |
106 | KCSAN_VALUE_CHANGE_MAYBE, |
107 | |
108 | /* |
109 | * Did not observe a value-change, and it is invalid to report the race. |
110 | */ |
111 | KCSAN_VALUE_CHANGE_FALSE, |
112 | |
113 | /* |
114 | * The value was observed to change, and the race should be reported. |
115 | */ |
116 | KCSAN_VALUE_CHANGE_TRUE, |
117 | }; |
118 | |
119 | /* |
120 | * The calling thread hit and consumed a watchpoint: set the access information |
121 | * to be consumed by the reporting thread. No report is printed yet. |
122 | */ |
123 | void kcsan_report_set_info(const volatile void *ptr, size_t size, int access_type, |
124 | unsigned long ip, int watchpoint_idx); |
125 | |
126 | /* |
127 | * The calling thread observed that the watchpoint it set up was hit and |
128 | * consumed: print the full report based on information set by the racing |
129 | * thread. |
130 | */ |
131 | void kcsan_report_known_origin(const volatile void *ptr, size_t size, int access_type, |
132 | unsigned long ip, enum kcsan_value_change value_change, |
133 | int watchpoint_idx, u64 old, u64 new, u64 mask); |
134 | |
135 | /* |
136 | * No other thread was observed to race with the access, but the data value |
137 | * before and after the stall differs. Reports a race of "unknown origin". |
138 | */ |
139 | void kcsan_report_unknown_origin(const volatile void *ptr, size_t size, int access_type, |
140 | unsigned long ip, u64 old, u64 new, u64 mask); |
141 | |
142 | #endif /* _KERNEL_KCSAN_KCSAN_H */ |
143 | |