LXR linux/kernel/locking/lockdep

   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
  50#define LOCKDEP_STATE(__STATE)  LOCKF_ENABLED_##__STATE |
  51static 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 |
  57static 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 |
  63static 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 |
  69static 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
 124extern struct lock_chain lock_chains[];
 125
 126#define LOCK_USAGE_CHARS (2*XXX_LOCK_USAGE_STATES + 1)
 127
 128extern void get_usage_chars(struct lock_class *class,
 129                            char usage[LOCK_USAGE_CHARS]);
 130
 131extern const char *__get_key_name(const struct lockdep_subclass_key *key,
 132                                  char *str);
 133
 134struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i);
 135
 136extern unsigned long nr_lock_classes;
 137extern unsigned long nr_zapped_classes;
 138extern unsigned long nr_zapped_lock_chains;
 139extern unsigned long nr_list_entries;
 140long lockdep_next_lockchain(long i);
 141unsigned long lock_chain_count(void);
 142extern unsigned long nr_stack_trace_entries;
 143
 144extern unsigned int nr_hardirq_chains;
 145extern unsigned int nr_softirq_chains;
 146extern unsigned int nr_process_chains;
 147extern unsigned int nr_free_chain_hlocks;
 148extern unsigned int nr_lost_chain_hlocks;
 149extern unsigned int nr_large_chain_blocks;
 150
 151extern unsigned int max_lockdep_depth;
 152extern unsigned int max_bfs_queue_depth;
 153extern unsigned long max_lock_class_idx;
 154
 155extern struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
 156extern unsigned long lock_classes_in_use[];
 157
 158#ifdef CONFIG_PROVE_LOCKING
 159extern unsigned long lockdep_count_forward_deps(struct lock_class *);
 160extern unsigned long lockdep_count_backward_deps(struct lock_class *);
 161#ifdef CONFIG_TRACE_IRQFLAGS
 162u64 lockdep_stack_trace_count(void);
 163u64 lockdep_stack_hash_count(void);
 164#endif
 165#else
 166static inline unsigned long
 167lockdep_count_forward_deps(struct lock_class *class)
 168{
 169        return 0;
 170}
 171static inline unsigned long
 172lockdep_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 */
 186struct 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
 210DECLARE_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
 236static 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
 244static 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