1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3  * kernel/lockdep_internals.h
4  *
5  * Runtime locking correctness validator
6  *
7  * lockdep subsystem internal functions and variables.
8  */
9 
10 /*
11  * Lock-class usage-state bits:
12  */
13 enum lock_usage_bit {
14 #define LOCKDEP_STATE(__STATE)		\
15 	LOCK_USED_IN_##__STATE,		\
16 	LOCK_USED_IN_##__STATE##_READ,	\
17 	LOCK_ENABLED_##__STATE,		\
18 	LOCK_ENABLED_##__STATE##_READ,
19 #include "lockdep_states.h"
20 #undef LOCKDEP_STATE
21 	LOCK_USED,
22 	LOCK_USED_READ,
23 	LOCK_USAGE_STATES,
24 };
25 
26 /* states after LOCK_USED_READ are not traced and printed */
27 static_assert(LOCK_TRACE_STATES == LOCK_USAGE_STATES);
28 
29 #define LOCK_USAGE_READ_MASK 1
30 #define LOCK_USAGE_DIR_MASK  2
31 #define LOCK_USAGE_STATE_MASK (~(LOCK_USAGE_READ_MASK | LOCK_USAGE_DIR_MASK))
32 
33 /*
34  * Usage-state bitmasks:
35  */
36 #define __LOCKF(__STATE)	LOCKF_##__STATE = (1 << LOCK_##__STATE),
37 
38 enum {
39 #define LOCKDEP_STATE(__STATE)						\
40 	__LOCKF(USED_IN_##__STATE)					\
41 	__LOCKF(USED_IN_##__STATE##_READ)				\
42 	__LOCKF(ENABLED_##__STATE)					\
43 	__LOCKF(ENABLED_##__STATE##_READ)
44 #include "lockdep_states.h"
45 #undef LOCKDEP_STATE
46 	__LOCKF(USED)
47 	__LOCKF(USED_READ)
48 };
49 
50 #define LOCKDEP_STATE(__STATE)	LOCKF_ENABLED_##__STATE |
51 static const unsigned long LOCKF_ENABLED_IRQ =
52 #include "lockdep_states.h"
53 	0;
54 #undef LOCKDEP_STATE
55 
56 #define LOCKDEP_STATE(__STATE)	LOCKF_USED_IN_##__STATE |
57 static const unsigned long LOCKF_USED_IN_IRQ =
58 #include "lockdep_states.h"
59 	0;
60 #undef LOCKDEP_STATE
61 
62 #define LOCKDEP_STATE(__STATE)	LOCKF_ENABLED_##__STATE##_READ |
63 static const unsigned long LOCKF_ENABLED_IRQ_READ =
64 #include "lockdep_states.h"
65 	0;
66 #undef LOCKDEP_STATE
67 
68 #define LOCKDEP_STATE(__STATE)	LOCKF_USED_IN_##__STATE##_READ |
69 static const unsigned long LOCKF_USED_IN_IRQ_READ =
70 #include "lockdep_states.h"
71 	0;
72 #undef LOCKDEP_STATE
73 
74 #define LOCKF_ENABLED_IRQ_ALL (LOCKF_ENABLED_IRQ | LOCKF_ENABLED_IRQ_READ)
75 #define LOCKF_USED_IN_IRQ_ALL (LOCKF_USED_IN_IRQ | LOCKF_USED_IN_IRQ_READ)
76 
77 #define LOCKF_IRQ (LOCKF_ENABLED_IRQ | LOCKF_USED_IN_IRQ)
78 #define LOCKF_IRQ_READ (LOCKF_ENABLED_IRQ_READ | LOCKF_USED_IN_IRQ_READ)
79 
80 /*
81  * CONFIG_LOCKDEP_SMALL is defined for sparc. Sparc requires .text,
82  * .data and .bss to fit in required 32MB limit for the kernel. With
83  * CONFIG_LOCKDEP we could go over this limit and cause system boot-up problems.
84  * So, reduce the static allocations for lockdeps related structures so that
85  * everything fits in current required size limit.
86  */
87 #ifdef CONFIG_LOCKDEP_SMALL
88 /*
89  * MAX_LOCKDEP_ENTRIES is the maximum number of lock dependencies
90  * we track.
91  *
92  * We use the per-lock dependency maps in two ways: we grow it by adding
93  * every to-be-taken lock to all currently held lock's own dependency
94  * table (if it's not there yet), and we check it for lock order
95  * conflicts and deadlocks.
96  */
97 #define MAX_LOCKDEP_ENTRIES	16384UL
98 #define MAX_LOCKDEP_CHAINS_BITS	15
99 #define MAX_STACK_TRACE_ENTRIES	262144UL
100 #define STACK_TRACE_HASH_SIZE	8192
101 #else
102 #define MAX_LOCKDEP_ENTRIES	(1UL << CONFIG_LOCKDEP_BITS)
103 
104 #define MAX_LOCKDEP_CHAINS_BITS	CONFIG_LOCKDEP_CHAINS_BITS
105 
106 /*
107  * Stack-trace: tightly packed array of stack backtrace
108  * addresses. Protected by the hash_lock.
109  */
110 #define MAX_STACK_TRACE_ENTRIES	(1UL << CONFIG_LOCKDEP_STACK_TRACE_BITS)
111 #define STACK_TRACE_HASH_SIZE	(1 << CONFIG_LOCKDEP_STACK_TRACE_HASH_BITS)
112 #endif
113 
114 /*
115  * Bit definitions for lock_chain.irq_context
116  */
117 #define LOCK_CHAIN_SOFTIRQ_CONTEXT	(1 << 0)
118 #define LOCK_CHAIN_HARDIRQ_CONTEXT	(1 << 1)
119 
120 #define MAX_LOCKDEP_CHAINS	(1UL << MAX_LOCKDEP_CHAINS_BITS)
121 
122 #define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5)
123 
124 extern struct lock_chain lock_chains[];
125 
126 #define LOCK_USAGE_CHARS (2*XXX_LOCK_USAGE_STATES + 1)
127 
128 extern void get_usage_chars(struct lock_class *class,
129 			    char usage[LOCK_USAGE_CHARS]);
130 
131 extern const char *__get_key_name(const struct lockdep_subclass_key *key,
132 				  char *str);
133 
134 struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i);
135 
136 extern unsigned long nr_lock_classes;
137 extern unsigned long nr_zapped_classes;
138 extern unsigned long nr_zapped_lock_chains;
139 extern unsigned long nr_list_entries;
140 long lockdep_next_lockchain(long i);
141 unsigned long lock_chain_count(void);
142 extern unsigned long nr_stack_trace_entries;
143 
144 extern unsigned int nr_hardirq_chains;
145 extern unsigned int nr_softirq_chains;
146 extern unsigned int nr_process_chains;
147 extern unsigned int nr_free_chain_hlocks;
148 extern unsigned int nr_lost_chain_hlocks;
149 extern unsigned int nr_large_chain_blocks;
150 
151 extern unsigned int max_lockdep_depth;
152 extern unsigned int max_bfs_queue_depth;
153 extern unsigned long max_lock_class_idx;
154 
155 extern struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
156 extern unsigned long lock_classes_in_use[];
157 
158 #ifdef CONFIG_PROVE_LOCKING
159 extern unsigned long lockdep_count_forward_deps(struct lock_class *);
160 extern unsigned long lockdep_count_backward_deps(struct lock_class *);
161 #ifdef CONFIG_TRACE_IRQFLAGS
162 u64 lockdep_stack_trace_count(void);
163 u64 lockdep_stack_hash_count(void);
164 #endif
165 #else
166 static inline unsigned long
167 lockdep_count_forward_deps(struct lock_class *class)
168 {
169 	return 0;
170 }
171 static inline unsigned long
172 lockdep_count_backward_deps(struct lock_class *class)
173 {
174 	return 0;
175 }
176 #endif
177 
178 #ifdef CONFIG_DEBUG_LOCKDEP
179 
180 #include <asm/local.h>
181 /*
182  * Various lockdep statistics.
183  * We want them per cpu as they are often accessed in fast path
184  * and we want to avoid too much cache bouncing.
185  */
186 struct lockdep_stats {
187 	unsigned long  chain_lookup_hits;
188 	unsigned int   chain_lookup_misses;
189 	unsigned long  hardirqs_on_events;
190 	unsigned long  hardirqs_off_events;
191 	unsigned long  redundant_hardirqs_on;
192 	unsigned long  redundant_hardirqs_off;
193 	unsigned long  softirqs_on_events;
194 	unsigned long  softirqs_off_events;
195 	unsigned long  redundant_softirqs_on;
196 	unsigned long  redundant_softirqs_off;
197 	int            nr_unused_locks;
198 	unsigned int   nr_redundant_checks;
199 	unsigned int   nr_redundant;
200 	unsigned int   nr_cyclic_checks;
201 	unsigned int   nr_find_usage_forwards_checks;
202 	unsigned int   nr_find_usage_backwards_checks;
203 
204 	/*
205 	 * Per lock class locking operation stat counts
206 	 */
207 	unsigned long lock_class_ops[MAX_LOCKDEP_KEYS];
208 };
209 
210 DECLARE_PER_CPU(struct lockdep_stats, lockdep_stats);
211 
212 #define __debug_atomic_inc(ptr)					\
213 	this_cpu_inc(lockdep_stats.ptr);
214 
215 #define debug_atomic_inc(ptr)			{		\
216 	WARN_ON_ONCE(!irqs_disabled());				\
217 	__this_cpu_inc(lockdep_stats.ptr);			\
218 }
219 
220 #define debug_atomic_dec(ptr)			{		\
221 	WARN_ON_ONCE(!irqs_disabled());				\
222 	__this_cpu_dec(lockdep_stats.ptr);			\
223 }
224 
225 #define debug_atomic_read(ptr)		({				\
226 	struct lockdep_stats *__cpu_lockdep_stats;			\
227 	unsigned long long __total = 0;					\
228 	int __cpu;							\
229 	for_each_possible_cpu(__cpu) {					\
230 		__cpu_lockdep_stats = &per_cpu(lockdep_stats, __cpu);	\
231 		__total += __cpu_lockdep_stats->ptr;			\
232 	}								\
233 	__total;							\
234 })
235 
236 static inline void debug_class_ops_inc(struct lock_class *class)
237 {
238 	int idx;
239 
240 	idx = class - lock_classes;
241 	__debug_atomic_inc(lock_class_ops[idx]);
242 }
243 
244 static inline unsigned long debug_class_ops_read(struct lock_class *class)
245 {
246 	int idx, cpu;
247 	unsigned long ops = 0;
248 
249 	idx = class - lock_classes;
250 	for_each_possible_cpu(cpu)
251 		ops += per_cpu(lockdep_stats.lock_class_ops[idx], cpu);
252 	return ops;
253 }
254 
255 #else
256 # define __debug_atomic_inc(ptr)	do { } while (0)
257 # define debug_atomic_inc(ptr)		do { } while (0)
258 # define debug_atomic_dec(ptr)		do { } while (0)
259 # define debug_atomic_read(ptr)		0
260 # define debug_class_ops_inc(ptr)	do { } while (0)
261 #endif
262