include/linux/lockdep_types.h

   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
  17 enum 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
  33 enum 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  */
  70 struct lockdep_subclass_key {
  71         char __one_byte;
  72 } __attribute__ ((__packed__));
  73
  74 /* hash_entry is used to keep track of dynamically allocated keys. */
  75 struct lock_class_key {
  76         union {
  77                 struct hlist_node               hash_entry;
  78                 struct lockdep_subclass_key     subkeys[MAX_LOCKDEP_SUBCLASSES];
  79         };
  80 };
  81
  82 extern struct lock_class_key __lockdep_no_validate__;
  83 extern struct lock_class_key __lockdep_no_track__;
  84
  85 struct lock_trace;
  86
  87 #define LOCKSTAT_POINTS         4
  88
  89 struct lockdep_map;
  90 typedef int (*lock_cmp_fn)(const struct lockdep_map *a,
  91                            const struct lockdep_map *b);
  92 typedef 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  */
  98 struct 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
 150 struct lock_time {
 151         s64                             min;
 152         s64                             max;
 153         s64                             total;
 154         unsigned long                   nr;
 155 };
 156
 157 enum 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
 168 struct 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
 178 struct lock_class_stats lock_stats(struct lock_class *class);
 179 void 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  */
 186 struct 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
 200 struct 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
 206 struct 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  */
 264 struct lock_class_key { };
 265
 266 /*
 267  * The lockdep_map takes no space if lockdep is disabled:
 268  */
 269 struct lockdep_map { };
 270
 271 struct pin_cookie { };
 272
 273 #endif /* !LOCKDEP */
 274
 275 #endif /* __LINUX_LOCKDEP_TYPES_H */