lockdep_internals.h

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/*
 * kernel/lockdep_internals.h
 *
 * Runtime locking correctness validator
 *
 * lockdep subsystem internal functions and variables.
 */

/*
 * Lock-class usage-state bits:
 */
enum lock_usage_bit {
#define LOCKDEP_STATE(__STATE)      \
    LOCK_USED_IN_##__STATE,     \
    LOCK_USED_IN_##__STATE##_READ,  \
    LOCK_ENABLED_##__STATE,     \
    LOCK_ENABLED_##__STATE##_READ,
#include "lockdep_states.h"
#undef LOCKDEP_STATE
    LOCK_USED,
    LOCK_USAGE_STATES
};

/*
 * Usage-state bitmasks:
 */
#define __LOCKF(__STATE)    LOCKF_##__STATE = (1 << LOCK_##__STATE),

enum {
#define LOCKDEP_STATE(__STATE)                      \
    __LOCKF(USED_IN_##__STATE)                  \
    __LOCKF(USED_IN_##__STATE##_READ)               \
    __LOCKF(ENABLED_##__STATE)                  \
    __LOCKF(ENABLED_##__STATE##_READ)
#include "lockdep_states.h"
#undef LOCKDEP_STATE
    __LOCKF(USED)
};

#define LOCKF_ENABLED_IRQ (LOCKF_ENABLED_HARDIRQ | LOCKF_ENABLED_SOFTIRQ)
#define LOCKF_USED_IN_IRQ (LOCKF_USED_IN_HARDIRQ | LOCKF_USED_IN_SOFTIRQ)

#define LOCKF_ENABLED_IRQ_READ \
        (LOCKF_ENABLED_HARDIRQ_READ | LOCKF_ENABLED_SOFTIRQ_READ)
#define LOCKF_USED_IN_IRQ_READ \
        (LOCKF_USED_IN_HARDIRQ_READ | LOCKF_USED_IN_SOFTIRQ_READ)

/*
 * MAX_LOCKDEP_ENTRIES is the maximum number of lock dependencies
 * we track.
 *
 * We use the per-lock dependency maps in two ways: we grow it by adding
 * every to-be-taken lock to all currently held lock's own dependency
 * table (if it's not there yet), and we check it for lock order
 * conflicts and deadlocks.
 */
#define MAX_LOCKDEP_ENTRIES 16384UL

#define MAX_LOCKDEP_CHAINS_BITS 15
#define MAX_LOCKDEP_CHAINS  (1UL << MAX_LOCKDEP_CHAINS_BITS)

#define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5)

/*
 * Stack-trace: tightly packed array of stack backtrace
 * addresses. Protected by the hash_lock.
 */
#define MAX_STACK_TRACE_ENTRIES 262144UL

extern struct list_head all_lock_classes;
extern struct lock_chain lock_chains[];

#define LOCK_USAGE_CHARS (1+LOCK_USAGE_STATES/2)

extern void get_usage_chars(struct lock_class *class,
                char usage[LOCK_USAGE_CHARS]);

extern const char * __get_key_name(struct lockdep_subclass_key *key, char *str);

struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i);

extern unsigned long nr_lock_classes;
extern unsigned long nr_list_entries;
extern unsigned long nr_lock_chains;
extern int nr_chain_hlocks;
extern unsigned long nr_stack_trace_entries;

extern unsigned int nr_hardirq_chains;
extern unsigned int nr_softirq_chains;
extern unsigned int nr_process_chains;
extern unsigned int max_lockdep_depth;
extern unsigned int max_recursion_depth;

extern unsigned int max_bfs_queue_depth;

#ifdef CONFIG_PROVE_LOCKING
extern unsigned long lockdep_count_forward_deps(struct lock_class *);
extern unsigned long lockdep_count_backward_deps(struct lock_class *);
#else
static inline unsigned long
lockdep_count_forward_deps(struct lock_class *class)
{
    return 0;
}
static inline unsigned long
lockdep_count_backward_deps(struct lock_class *class)
{
    return 0;
}
#endif

#ifdef CONFIG_DEBUG_LOCKDEP

#include <asm/local.h>
/*
 * Various lockdep statistics.
 * We want them per cpu as they are often accessed in fast path
 * and we want to avoid too much cache bouncing.
 */
struct lockdep_stats {
    int chain_lookup_hits;
    int chain_lookup_misses;
    int hardirqs_on_events;
    int hardirqs_off_events;
    int redundant_hardirqs_on;
    int redundant_hardirqs_off;
    int softirqs_on_events;
    int softirqs_off_events;
    int redundant_softirqs_on;
    int redundant_softirqs_off;
    int nr_unused_locks;
    int nr_cyclic_checks;
    int nr_cyclic_check_recursions;
    int nr_find_usage_forwards_checks;
    int nr_find_usage_forwards_recursions;
    int nr_find_usage_backwards_checks;
    int nr_find_usage_backwards_recursions;
};

DECLARE_PER_CPU(struct lockdep_stats, lockdep_stats);

#define __debug_atomic_inc(ptr)                 \
    this_cpu_inc(lockdep_stats.ptr);

#define debug_atomic_inc(ptr)           {       \
    WARN_ON_ONCE(!irqs_disabled());             \
    __this_cpu_inc(lockdep_stats.ptr);          \
}

#define debug_atomic_dec(ptr)           {       \
    WARN_ON_ONCE(!irqs_disabled());             \
    __this_cpu_dec(lockdep_stats.ptr);          \
}

#define debug_atomic_read(ptr)      ({              \
    struct lockdep_stats *__cpu_lockdep_stats;          \
    unsigned long long __total = 0;                 \
    int __cpu;                          \
    for_each_possible_cpu(__cpu) {                  \
        __cpu_lockdep_stats = &per_cpu(lockdep_stats, __cpu);   \
        __total += __cpu_lockdep_stats->ptr;            \
    }                               \
    __total;                            \
})
#else
# define __debug_atomic_inc(ptr)    do { } while (0)
# define debug_atomic_inc(ptr)      do { } while (0)
# define debug_atomic_dec(ptr)      do { } while (0)
# define debug_atomic_read(ptr)     0
#endif