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   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  * MAX_LOCKDEP_ENTRIES is the maximum number of lock dependencies
  50  * we track.
  51  *
  52  * We use the per-lock dependency maps in two ways: we grow it by adding
  53  * every to-be-taken lock to all currently held lock's own dependency
  54  * table (if it's not there yet), and we check it for lock order
  55  * conflicts and deadlocks.
  56  */
  57 #define MAX_LOCKDEP_ENTRIES     16384UL
  58
  59 #define MAX_LOCKDEP_CHAINS_BITS 15
  60 #define MAX_LOCKDEP_CHAINS      (1UL << MAX_LOCKDEP_CHAINS_BITS)
  61
  62 #define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5)
  63
  64 /*
  65  * Stack-trace: tightly packed array of stack backtrace
  66  * addresses. Protected by the hash_lock.
  67  */
  68 #define MAX_STACK_TRACE_ENTRIES 262144UL
  69
  70 extern struct list_head all_lock_classes;
  71 extern struct lock_chain lock_chains[];
  72
  73 #define LOCK_USAGE_CHARS (1+LOCK_USAGE_STATES/2)
  74
  75 extern void get_usage_chars(struct lock_class *class,
  76                             char usage[LOCK_USAGE_CHARS]);
  77
  78 extern const char * __get_key_name(struct lockdep_subclass_key *key, char *str);
  79
  80 struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i);
  81
  82 extern unsigned long nr_lock_classes;
  83 extern unsigned long nr_list_entries;
  84 extern unsigned long nr_lock_chains;
  85 extern int nr_chain_hlocks;
  86 extern unsigned long nr_stack_trace_entries;
  87
  88 extern unsigned int nr_hardirq_chains;
  89 extern unsigned int nr_softirq_chains;
  90 extern unsigned int nr_process_chains;
  91 extern unsigned int max_lockdep_depth;
  92 extern unsigned int max_recursion_depth;
  93
  94 #ifdef CONFIG_PROVE_LOCKING
  95 extern unsigned long lockdep_count_forward_deps(struct lock_class *);
  96 extern unsigned long lockdep_count_backward_deps(struct lock_class *);
  97 #else
  98 static inline unsigned long
  99 lockdep_count_forward_deps(struct lock_class *class)
 100 {
 101         return 0;
 102 }
 103 static inline unsigned long
 104 lockdep_count_backward_deps(struct lock_class *class)
 105 {
 106         return 0;
 107 }
 108 #endif
 109
 110 #ifdef CONFIG_DEBUG_LOCKDEP
 111 /*
 112  * Various lockdep statistics:
 113  */
 114 extern atomic_t chain_lookup_hits;
 115 extern atomic_t chain_lookup_misses;
 116 extern atomic_t hardirqs_on_events;
 117 extern atomic_t hardirqs_off_events;
 118 extern atomic_t redundant_hardirqs_on;
 119 extern atomic_t redundant_hardirqs_off;
 120 extern atomic_t softirqs_on_events;
 121 extern atomic_t softirqs_off_events;
 122 extern atomic_t redundant_softirqs_on;
 123 extern atomic_t redundant_softirqs_off;
 124 extern atomic_t nr_unused_locks;
 125 extern atomic_t nr_cyclic_checks;
 126 extern atomic_t nr_cyclic_check_recursions;
 127 extern atomic_t nr_find_usage_forwards_checks;
 128 extern atomic_t nr_find_usage_forwards_recursions;
 129 extern atomic_t nr_find_usage_backwards_checks;
 130 extern atomic_t nr_find_usage_backwards_recursions;
 131 # define debug_atomic_inc(ptr)          atomic_inc(ptr)
 132 # define debug_atomic_dec(ptr)          atomic_dec(ptr)
 133 # define debug_atomic_read(ptr)         atomic_read(ptr)
 134 #else
 135 # define debug_atomic_inc(ptr)          do { } while (0)
 136 # define debug_atomic_dec(ptr)          do { } while (0)
 137 # define debug_atomic_read(ptr)         0
 138 #endif
 139
 140
 141 extern unsigned long nr_list_entries;
 142 extern struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
 143 extern unsigned long bfs_accessed[];
 144
 145 /*For good efficiency of modular, we use power of 2*/
 146 #define  MAX_CIRCULAR_QUE_SIZE      4096UL
 147
 148 /* The circular_queue and helpers is used to implement the
 149  * breadth-first search(BFS)algorithem, by which we can build
 150  * the shortest path from the next lock to be acquired to the
 151  * previous held lock if there is a circular between them.
 152  * */
 153 struct circular_queue{
 154         unsigned long element[MAX_CIRCULAR_QUE_SIZE];
 155         unsigned int  front, rear;
 156 };
 157
 158 static inline void __cq_init(struct circular_queue *cq)
 159 {
 160         cq->front = cq->rear = 0;
 161         bitmap_zero(bfs_accessed, MAX_LOCKDEP_ENTRIES);
 162 }
 163
 164 static inline int __cq_empty(struct circular_queue *cq)
 165 {
 166         return (cq->front == cq->rear);
 167 }
 168
 169 static inline int __cq_full(struct circular_queue *cq)
 170 {
 171         return ((cq->rear + 1)&(MAX_CIRCULAR_QUE_SIZE-1))  == cq->front;
 172 }
 173
 174 static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem)
 175 {
 176         if (__cq_full(cq))
 177                 return -1;
 178
 179         cq->element[cq->rear] = elem;
 180         cq->rear = (cq->rear + 1)&(MAX_CIRCULAR_QUE_SIZE-1);
 181         return 0;
 182 }
 183
 184 static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem)
 185 {
 186         if (__cq_empty(cq))
 187                 return -1;
 188
 189         *elem = cq->element[cq->front];
 190         cq->front = (cq->front + 1)&(MAX_CIRCULAR_QUE_SIZE-1);
 191         return 0;
 192 }
 193
 194 static inline int __cq_get_elem_count(struct circular_queue *cq)
 195 {
 196         return (cq->rear - cq->front)&(MAX_CIRCULAR_QUE_SIZE-1);
 197 }
 198
 199 static inline void mark_lock_accessed(struct lock_list *lock,
 200                                         struct lock_list *parent)
 201 {
 202         unsigned long nr;
 203         nr = lock - list_entries;
 204         WARN_ON(nr >= nr_list_entries);
 205         lock->parent = parent;
 206         set_bit(nr, bfs_accessed);
 207 }
 208
 209 static inline unsigned long lock_accessed(struct lock_list *lock)
 210 {
 211         unsigned long nr;
 212         nr = lock - list_entries;
 213         WARN_ON(nr >= nr_list_entries);
 214         return test_bit(nr, bfs_accessed);
 215 }
 216
 217 static inline struct lock_list *get_lock_parent(struct lock_list *child)
 218 {
 219         return child->parent;
 220 }
 221
 222 static inline unsigned long get_lock_depth(struct lock_list *child)
 223 {
 224         unsigned long depth = 0;
 225         struct lock_list *parent;
 226
 227         while ((parent = get_lock_parent(child))) {
 228                 child = parent;
 229                 depth++;
 230         }
 231         return depth;
 232 }