1 /*
2  * kernel/lockdep_internals.h
3  *
4  * Runtime locking correctness validator
5  *
6  * lockdep subsystem internal functions and variables.
7  */
8 
9 /*
10  * Lock-class usage-state bits:
11  */
12 enum lock_usage_bit {
13 #define LOCKDEP_STATE(__STATE)		\
14 	LOCK_USED_IN_##__STATE,		\
15 	LOCK_USED_IN_##__STATE##_READ,	\
16 	LOCK_ENABLED_##__STATE,		\
17 	LOCK_ENABLED_##__STATE##_READ,
18 #include "lockdep_states.h"
19 #undef LOCKDEP_STATE
20 	LOCK_USED,
21 	LOCK_USAGE_STATES
22 };
23 
24 /*
25  * Usage-state bitmasks:
26  */
27 #define __LOCKF(__STATE)	LOCKF_##__STATE = (1 << LOCK_##__STATE),
28 
29 enum {
30 #define LOCKDEP_STATE(__STATE)						\
31 	__LOCKF(USED_IN_##__STATE)					\
32 	__LOCKF(USED_IN_##__STATE##_READ)				\
33 	__LOCKF(ENABLED_##__STATE)					\
34 	__LOCKF(ENABLED_##__STATE##_READ)
35 #include "lockdep_states.h"
36 #undef LOCKDEP_STATE
37 	__LOCKF(USED)
38 };
39 
40 #define LOCKF_ENABLED_IRQ (LOCKF_ENABLED_HARDIRQ | LOCKF_ENABLED_SOFTIRQ)
41 #define LOCKF_USED_IN_IRQ (LOCKF_USED_IN_HARDIRQ | LOCKF_USED_IN_SOFTIRQ)
42 
43 #define LOCKF_ENABLED_IRQ_READ \
44 		(LOCKF_ENABLED_HARDIRQ_READ | LOCKF_ENABLED_SOFTIRQ_READ)
45 #define LOCKF_USED_IN_IRQ_READ \
46 		(LOCKF_USED_IN_HARDIRQ_READ | LOCKF_USED_IN_SOFTIRQ_READ)
47 
48 /*
49  * CONFIG_LOCKDEP_SMALL is defined for sparc. Sparc requires .text,
50  * .data and .bss to fit in required 32MB limit for the kernel. With
51  * CONFIG_LOCKDEP we could go over this limit and cause system boot-up problems.
52  * So, reduce the static allocations for lockdeps related structures so that
53  * everything fits in current required size limit.
54  */
55 #ifdef CONFIG_LOCKDEP_SMALL
56 /*
57  * MAX_LOCKDEP_ENTRIES is the maximum number of lock dependencies
58  * we track.
59  *
60  * We use the per-lock dependency maps in two ways: we grow it by adding
61  * every to-be-taken lock to all currently held lock's own dependency
62  * table (if it's not there yet), and we check it for lock order
63  * conflicts and deadlocks.
64  */
65 #define MAX_LOCKDEP_ENTRIES	16384UL
66 #define MAX_LOCKDEP_CHAINS_BITS	15
67 #define MAX_STACK_TRACE_ENTRIES	262144UL
68 #else
69 #define MAX_LOCKDEP_ENTRIES	32768UL
70 
71 #define MAX_LOCKDEP_CHAINS_BITS	16
72 
73 /*
74  * Stack-trace: tightly packed array of stack backtrace
75  * addresses. Protected by the hash_lock.
76  */
77 #define MAX_STACK_TRACE_ENTRIES	524288UL
78 #endif
79 
80 #define MAX_LOCKDEP_CHAINS	(1UL << MAX_LOCKDEP_CHAINS_BITS)
81 
82 #define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5)
83 
84 extern struct list_head all_lock_classes;
85 extern struct lock_chain lock_chains[];
86 
87 #define LOCK_USAGE_CHARS (1+LOCK_USAGE_STATES/2)
88 
89 extern void get_usage_chars(struct lock_class *class,
90 			    char usage[LOCK_USAGE_CHARS]);
91 
92 extern const char * __get_key_name(struct lockdep_subclass_key *key, char *str);
93 
94 struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i);
95 
96 extern unsigned long nr_lock_classes;
97 extern unsigned long nr_list_entries;
98 extern unsigned long nr_lock_chains;
99 extern int nr_chain_hlocks;
100 extern unsigned long nr_stack_trace_entries;
101 
102 extern unsigned int nr_hardirq_chains;
103 extern unsigned int nr_softirq_chains;
104 extern unsigned int nr_process_chains;
105 extern unsigned int max_lockdep_depth;
106 extern unsigned int max_recursion_depth;
107 
108 extern unsigned int max_bfs_queue_depth;
109 
110 #ifdef CONFIG_PROVE_LOCKING
111 extern unsigned long lockdep_count_forward_deps(struct lock_class *);
112 extern unsigned long lockdep_count_backward_deps(struct lock_class *);
113 #else
114 static inline unsigned long
115 lockdep_count_forward_deps(struct lock_class *class)
116 {
117 	return 0;
118 }
119 static inline unsigned long
120 lockdep_count_backward_deps(struct lock_class *class)
121 {
122 	return 0;
123 }
124 #endif
125 
126 #ifdef CONFIG_DEBUG_LOCKDEP
127 
128 #include <asm/local.h>
129 /*
130  * Various lockdep statistics.
131  * We want them per cpu as they are often accessed in fast path
132  * and we want to avoid too much cache bouncing.
133  */
134 struct lockdep_stats {
135 	int	chain_lookup_hits;
136 	int	chain_lookup_misses;
137 	int	hardirqs_on_events;
138 	int	hardirqs_off_events;
139 	int	redundant_hardirqs_on;
140 	int	redundant_hardirqs_off;
141 	int	softirqs_on_events;
142 	int	softirqs_off_events;
143 	int	redundant_softirqs_on;
144 	int	redundant_softirqs_off;
145 	int	nr_unused_locks;
146 	int	nr_redundant_checks;
147 	int	nr_redundant;
148 	int	nr_cyclic_checks;
149 	int	nr_cyclic_check_recursions;
150 	int	nr_find_usage_forwards_checks;
151 	int	nr_find_usage_forwards_recursions;
152 	int	nr_find_usage_backwards_checks;
153 	int	nr_find_usage_backwards_recursions;
154 };
155 
156 DECLARE_PER_CPU(struct lockdep_stats, lockdep_stats);
157 
158 #define __debug_atomic_inc(ptr)					\
159 	this_cpu_inc(lockdep_stats.ptr);
160 
161 #define debug_atomic_inc(ptr)			{		\
162 	WARN_ON_ONCE(!irqs_disabled());				\
163 	__this_cpu_inc(lockdep_stats.ptr);			\
164 }
165 
166 #define debug_atomic_dec(ptr)			{		\
167 	WARN_ON_ONCE(!irqs_disabled());				\
168 	__this_cpu_dec(lockdep_stats.ptr);			\
169 }
170 
171 #define debug_atomic_read(ptr)		({				\
172 	struct lockdep_stats *__cpu_lockdep_stats;			\
173 	unsigned long long __total = 0;					\
174 	int __cpu;							\
175 	for_each_possible_cpu(__cpu) {					\
176 		__cpu_lockdep_stats = &per_cpu(lockdep_stats, __cpu);	\
177 		__total += __cpu_lockdep_stats->ptr;			\
178 	}								\
179 	__total;							\
180 })
181 #else
182 # define __debug_atomic_inc(ptr)	do { } while (0)
183 # define debug_atomic_inc(ptr)		do { } while (0)
184 # define debug_atomic_dec(ptr)		do { } while (0)
185 # define debug_atomic_read(ptr)		0
186 #endif
187