lockdep_internals.h

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