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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Runtime locking correctness validator
4 *
5 * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
6 * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
7 *
8 * see Documentation/locking/lockdep-design.rst for more details.
9 */
10#ifndef __LINUX_LOCKDEP_TYPES_H
11#define __LINUX_LOCKDEP_TYPES_H
12
13#include <linux/types.h>
14
15#define MAX_LOCKDEP_SUBCLASSES 8UL
16
17enum lockdep_wait_type {
18 LD_WAIT_INV = 0, /* not checked, catch all */
19
20 LD_WAIT_FREE, /* wait free, rcu etc.. */
21 LD_WAIT_SPIN, /* spin loops, raw_spinlock_t etc.. */
22
23#ifdef CONFIG_PROVE_RAW_LOCK_NESTING
24 LD_WAIT_CONFIG, /* preemptible in PREEMPT_RT, spinlock_t etc.. */
25#else
26 LD_WAIT_CONFIG = LD_WAIT_SPIN,
27#endif
28 LD_WAIT_SLEEP, /* sleeping locks, mutex_t etc.. */
29
30 LD_WAIT_MAX, /* must be last */
31};
32
33enum lockdep_lock_type {
34 LD_LOCK_NORMAL = 0, /* normal, catch all */
35 LD_LOCK_PERCPU, /* percpu */
36 LD_LOCK_WAIT_OVERRIDE, /* annotation */
37 LD_LOCK_MAX,
38};
39
40#ifdef CONFIG_LOCKDEP
41
42/*
43 * We'd rather not expose kernel/lockdep_states.h this wide, but we do need
44 * the total number of states... :-(
45 *
46 * XXX_LOCK_USAGE_STATES is the number of lines in lockdep_states.h, for each
47 * of those we generates 4 states, Additionally we report on USED and USED_READ.
48 */
49#define XXX_LOCK_USAGE_STATES 2
50#define LOCK_TRACE_STATES (XXX_LOCK_USAGE_STATES*4 + 2)
51
52/*
53 * NR_LOCKDEP_CACHING_CLASSES ... Number of classes
54 * cached in the instance of lockdep_map
55 *
56 * Currently main class (subclass == 0) and single depth subclass
57 * are cached in lockdep_map. This optimization is mainly targeting
58 * on rq->lock. double_rq_lock() acquires this highly competitive with
59 * single depth.
60 */
61#define NR_LOCKDEP_CACHING_CLASSES 2
62
63/*
64 * A lockdep key is associated with each lock object. For static locks we use
65 * the lock address itself as the key. Dynamically allocated lock objects can
66 * have a statically or dynamically allocated key. Dynamically allocated lock
67 * keys must be registered before being used and must be unregistered before
68 * the key memory is freed.
69 */
70struct lockdep_subclass_key {
71 char __one_byte;
72} __attribute__ ((__packed__));
73
74/* hash_entry is used to keep track of dynamically allocated keys. */
75struct lock_class_key {
76 union {
77 struct hlist_node hash_entry;
78 struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES];
79 };
80};
81
82extern struct lock_class_key __lockdep_no_validate__;
83extern struct lock_class_key __lockdep_no_track__;
84
85struct lock_trace;
86
87#define LOCKSTAT_POINTS 4
88
89struct lockdep_map;
90typedef int (*lock_cmp_fn)(const struct lockdep_map *a,
91 const struct lockdep_map *b);
92typedef void (*lock_print_fn)(const struct lockdep_map *map);
93
94/*
95 * The lock-class itself. The order of the structure members matters.
96 * reinit_class() zeroes the key member and all subsequent members.
97 */
98struct lock_class {
99 /*
100 * class-hash:
101 */
102 struct hlist_node hash_entry;
103
104 /*
105 * Entry in all_lock_classes when in use. Entry in free_lock_classes
106 * when not in use. Instances that are being freed are on one of the
107 * zapped_classes lists.
108 */
109 struct list_head lock_entry;
110
111 /*
112 * These fields represent a directed graph of lock dependencies,
113 * to every node we attach a list of "forward" and a list of
114 * "backward" graph nodes.
115 */
116 struct list_head locks_after, locks_before;
117
118 const struct lockdep_subclass_key *key;
119 lock_cmp_fn cmp_fn;
120 lock_print_fn print_fn;
121
122 unsigned int subclass;
123 unsigned int dep_gen_id;
124
125 /*
126 * IRQ/softirq usage tracking bits:
127 */
128 unsigned long usage_mask;
129 const struct lock_trace *usage_traces[LOCK_TRACE_STATES];
130
131 const char *name;
132 /*
133 * Generation counter, when doing certain classes of graph walking,
134 * to ensure that we check one node only once:
135 */
136 int name_version;
137
138 u8 wait_type_inner;
139 u8 wait_type_outer;
140 u8 lock_type;
141 /* u8 hole; */
142
143#ifdef CONFIG_LOCK_STAT
144 unsigned long contention_point[LOCKSTAT_POINTS];
145 unsigned long contending_point[LOCKSTAT_POINTS];
146#endif
147} __no_randomize_layout;
148
149#ifdef CONFIG_LOCK_STAT
150struct lock_time {
151 s64 min;
152 s64 max;
153 s64 total;
154 unsigned long nr;
155};
156
157enum bounce_type {
158 bounce_acquired_write,
159 bounce_acquired_read,
160 bounce_contended_write,
161 bounce_contended_read,
162 nr_bounce_types,
163
164 bounce_acquired = bounce_acquired_write,
165 bounce_contended = bounce_contended_write,
166};
167
168struct lock_class_stats {
169 unsigned long contention_point[LOCKSTAT_POINTS];
170 unsigned long contending_point[LOCKSTAT_POINTS];
171 struct lock_time read_waittime;
172 struct lock_time write_waittime;
173 struct lock_time read_holdtime;
174 struct lock_time write_holdtime;
175 unsigned long bounces[nr_bounce_types];
176};
177
178void lock_stats(struct lock_class *class, struct lock_class_stats *stats);
179void clear_lock_stats(struct lock_class *class);
180#endif
181
182/*
183 * Map the lock object (the lock instance) to the lock-class object.
184 * This is embedded into specific lock instances:
185 */
186struct lockdep_map {
187 struct lock_class_key *key;
188 struct lock_class *class_cache[NR_LOCKDEP_CACHING_CLASSES];
189 const char *name;
190 u8 wait_type_outer; /* can be taken in this context */
191 u8 wait_type_inner; /* presents this context */
192 u8 lock_type;
193 /* u8 hole; */
194#ifdef CONFIG_LOCK_STAT
195 int cpu;
196 unsigned long ip;
197#endif
198};
199
200struct pin_cookie { unsigned int val; };
201
202#define MAX_LOCKDEP_KEYS_BITS 13
203#define MAX_LOCKDEP_KEYS (1UL << MAX_LOCKDEP_KEYS_BITS)
204#define INITIAL_CHAIN_KEY -1
205
206struct held_lock {
207 /*
208 * One-way hash of the dependency chain up to this point. We
209 * hash the hashes step by step as the dependency chain grows.
210 *
211 * We use it for dependency-caching and we skip detection
212 * passes and dependency-updates if there is a cache-hit, so
213 * it is absolutely critical for 100% coverage of the validator
214 * to have a unique key value for every unique dependency path
215 * that can occur in the system, to make a unique hash value
216 * as likely as possible - hence the 64-bit width.
217 *
218 * The task struct holds the current hash value (initialized
219 * with zero), here we store the previous hash value:
220 */
221 u64 prev_chain_key;
222 unsigned long acquire_ip;
223 struct lockdep_map *instance;
224 struct lockdep_map *nest_lock;
225#ifdef CONFIG_LOCK_STAT
226 u64 waittime_stamp;
227 u64 holdtime_stamp;
228#endif
229 /*
230 * class_idx is zero-indexed; it points to the element in
231 * lock_classes this held lock instance belongs to. class_idx is in
232 * the range from 0 to (MAX_LOCKDEP_KEYS-1) inclusive.
233 */
234 unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS;
235 /*
236 * The lock-stack is unified in that the lock chains of interrupt
237 * contexts nest ontop of process context chains, but we 'separate'
238 * the hashes by starting with 0 if we cross into an interrupt
239 * context, and we also keep do not add cross-context lock
240 * dependencies - the lock usage graph walking covers that area
241 * anyway, and we'd just unnecessarily increase the number of
242 * dependencies otherwise. [Note: hardirq and softirq contexts
243 * are separated from each other too.]
244 *
245 * The following field is used to detect when we cross into an
246 * interrupt context:
247 */
248 unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */
249 unsigned int trylock:1; /* 16 bits */
250
251 unsigned int read:2; /* see lock_acquire() comment */
252 unsigned int check:1; /* see lock_acquire() comment */
253 unsigned int hardirqs_off:1;
254 unsigned int sync:1;
255 unsigned int references:11; /* 32 bits */
256 unsigned int pin_count;
257};
258
259#else /* !CONFIG_LOCKDEP */
260
261/*
262 * The class key takes no space if lockdep is disabled:
263 */
264struct lock_class_key { };
265
266/*
267 * The lockdep_map takes no space if lockdep is disabled:
268 */
269struct lockdep_map { };
270
271struct pin_cookie { };
272
273#endif /* !LOCKDEP */
274
275#endif /* __LINUX_LOCKDEP_TYPES_H */
276

source code of linux/include/linux/lockdep_types.h