/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Runtime locking correctness validator
 *
 *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
 *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
 *
 * see Documentation/locking/lockdep-design.rst for more details.
 */
#ifndef __LINUX_LOCKDEP_H
#define __LINUX_LOCKDEP_H

#include <linux/lockdep_types.h>
#include <linux/smp.h>
#include <asm/percpu.h>

struct task_struct;

/* for sysctl */
extern int prove_locking;
extern int lock_stat;

#ifdef CONFIG_LOCKDEP

#include <linux/linkage.h>
#include <linux/list.h>
#include <linux/debug_locks.h>
#include <linux/stacktrace.h>

static inline void lockdep_copy_map(struct lockdep_map *to,
                                    struct lockdep_map *from)
{
        int i;

        *to = *from;
        /*
         * Since the class cache can be modified concurrently we could observe
         * half pointers (64bit arch using 32bit copy insns). Therefore clear
         * the caches and take the performance hit.
         *
         * XXX it doesn't work well with lockdep_set_class_and_subclass(), since
         *     that relies on cache abuse.
         */
        for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
                to->class_cache[i] = NULL;
}

/*
 * Every lock has a list of other locks that were taken after it.
 * We only grow the list, never remove from it:
 */
struct lock_list {
        struct list_head                entry;
        struct lock_class               *class;
        struct lock_class               *links_to;
        const struct lock_trace         *trace;
        u16                             distance;
        /* bitmap of different dependencies from head to this */
        u8                              dep;
        /* used by BFS to record whether "prev -> this" only has -(*R)-> */
        u8                              only_xr;

        /*
         * The parent field is used to implement breadth-first search, and the
         * bit 0 is reused to indicate if the lock has been accessed in BFS.
         */
        struct lock_list                *parent;
};

/**
 * struct lock_chain - lock dependency chain record
 *
 * @irq_context: the same as irq_context in held_lock below
 * @depth:       the number of held locks in this chain
 * @base:        the index in chain_hlocks for this chain
 * @entry:       the collided lock chains in lock_chain hash list
 * @chain_key:   the hash key of this lock_chain
 */
struct lock_chain {
        /* see BUILD_BUG_ON()s in add_chain_cache() */
        unsigned int                    irq_context :  2,
                                        depth       :  6,
                                        base        : 24;
        /* 4 byte hole */
        struct hlist_node               entry;
        u64                             chain_key;
};

#define MAX_LOCKDEP_KEYS_BITS           13
#define MAX_LOCKDEP_KEYS                (1UL << MAX_LOCKDEP_KEYS_BITS)
#define INITIAL_CHAIN_KEY               -1

struct held_lock {
        /*
         * One-way hash of the dependency chain up to this point. We
         * hash the hashes step by step as the dependency chain grows.
         *
         * We use it for dependency-caching and we skip detection
         * passes and dependency-updates if there is a cache-hit, so
         * it is absolutely critical for 100% coverage of the validator
         * to have a unique key value for every unique dependency path
         * that can occur in the system, to make a unique hash value
         * as likely as possible - hence the 64-bit width.
         *
         * The task struct holds the current hash value (initialized
         * with zero), here we store the previous hash value:
         */
        u64                             prev_chain_key;
        unsigned long                   acquire_ip;
        struct lockdep_map              *instance;
        struct lockdep_map              *nest_lock;
#ifdef CONFIG_LOCK_STAT
        u64                             waittime_stamp;
        u64                             holdtime_stamp;
#endif
        /*
         * class_idx is zero-indexed; it points to the element in
         * lock_classes this held lock instance belongs to. class_idx is in
         * the range from 0 to (MAX_LOCKDEP_KEYS-1) inclusive.
         */
        unsigned int                    class_idx:MAX_LOCKDEP_KEYS_BITS;
        /*
         * The lock-stack is unified in that the lock chains of interrupt
         * contexts nest ontop of process context chains, but we 'separate'
         * the hashes by starting with 0 if we cross into an interrupt
         * context, and we also keep do not add cross-context lock
         * dependencies - the lock usage graph walking covers that area
         * anyway, and we'd just unnecessarily increase the number of
         * dependencies otherwise. [Note: hardirq and softirq contexts
         * are separated from each other too.]
         *
         * The following field is used to detect when we cross into an
         * interrupt context:
         */
        unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */
        unsigned int trylock:1;                                         /* 16 bits */

        unsigned int read:2;        /* see lock_acquire() comment */
        unsigned int check:1;       /* see lock_acquire() comment */
        unsigned int hardirqs_off:1;
        unsigned int references:12;                                     /* 32 bits */
        unsigned int pin_count;
};

/*
 * Initialization, self-test and debugging-output methods:
 */
extern void lockdep_init(void);
extern void lockdep_reset(void);
extern void lockdep_reset_lock(struct lockdep_map *lock);
extern void lockdep_free_key_range(void *start, unsigned long size);
extern asmlinkage void lockdep_sys_exit(void);
extern void lockdep_set_selftest_task(struct task_struct *task);

extern void lockdep_init_task(struct task_struct *task);

/*
 * Split the recrursion counter in two to readily detect 'off' vs recursion.
 */
#define LOCKDEP_RECURSION_BITS  16
#define LOCKDEP_OFF             (1U << LOCKDEP_RECURSION_BITS)
#define LOCKDEP_RECURSION_MASK  (LOCKDEP_OFF - 1)

/*
 * lockdep_{off,on}() are macros to avoid tracing and kprobes; not inlines due
 * to header dependencies.
 */

#define lockdep_off()                                   \
do {                                                    \
        current->lockdep_recursion += LOCKDEP_OFF;      \
} while (0)

#define lockdep_on()                                    \
do {                                                    \
        current->lockdep_recursion -= LOCKDEP_OFF;      \
} while (0)

extern void lockdep_register_key(struct lock_class_key *key);
extern void lockdep_unregister_key(struct lock_class_key *key);

/*
 * These methods are used by specific locking variants (spinlocks,
 * rwlocks, mutexes and rwsems) to pass init/acquire/release events
 * to lockdep:
 */

extern void lockdep_init_map_waits(struct lockdep_map *lock, const char *name,
        struct lock_class_key *key, int subclass, short inner, short outer);

static inline void
lockdep_init_map_wait(struct lockdep_map *lock, const char *name,
                      struct lock_class_key *key, int subclass, short inner)
{
        lockdep_init_map_waits(lock, name, key, subclass, inner, LD_WAIT_INV);
}

static inline void lockdep_init_map(struct lockdep_map *lock, const char *name,
                             struct lock_class_key *key, int subclass)
{
        lockdep_init_map_wait(lock, name, key, subclass, LD_WAIT_INV);
}

/*
 * Reinitialize a lock key - for cases where there is special locking or
 * special initialization of locks so that the validator gets the scope
 * of dependencies wrong: they are either too broad (they need a class-split)
 * or they are too narrow (they suffer from a false class-split):
 */
#define lockdep_set_class(lock, key)                            \
        lockdep_init_map_waits(&(lock)->dep_map, #key, key, 0,  \
                               (lock)->dep_map.wait_type_inner, \
                               (lock)->dep_map.wait_type_outer)

#define lockdep_set_class_and_name(lock, key, name)             \
        lockdep_init_map_waits(&(lock)->dep_map, name, key, 0,  \
                               (lock)->dep_map.wait_type_inner, \
                               (lock)->dep_map.wait_type_outer)

#define lockdep_set_class_and_subclass(lock, key, sub)          \
        lockdep_init_map_waits(&(lock)->dep_map, #key, key, sub,\
                               (lock)->dep_map.wait_type_inner, \
                               (lock)->dep_map.wait_type_outer)

#define lockdep_set_subclass(lock, sub)                                 \
        lockdep_init_map_waits(&(lock)->dep_map, #lock, (lock)->dep_map.key, sub,\
                               (lock)->dep_map.wait_type_inner,         \
                               (lock)->dep_map.wait_type_outer)

#define lockdep_set_novalidate_class(lock) \
        lockdep_set_class_and_name(lock, &__lockdep_no_validate__, #lock)

/*
 * Compare locking classes
 */
#define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key)

static inline int lockdep_match_key(struct lockdep_map *lock,
                                    struct lock_class_key *key)
{
        return lock->key == key;
}

/*
 * Acquire a lock.
 *
 * Values for "read":
 *
 *   0: exclusive (write) acquire
 *   1: read-acquire (no recursion allowed)
 *   2: read-acquire with same-instance recursion allowed
 *
 * Values for check:
 *
 *   0: simple checks (freeing, held-at-exit-time, etc.)
 *   1: full validation
 */
extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
                         int trylock, int read, int check,
                         struct lockdep_map *nest_lock, unsigned long ip);

extern void lock_release(struct lockdep_map *lock, unsigned long ip);

/*
 * Same "read" as for lock_acquire(), except -1 means any.
 */
extern int lock_is_held_type(const struct lockdep_map *lock, int read);

static inline int lock_is_held(const struct lockdep_map *lock)
{
        return lock_is_held_type(lock, -1);
}

#define lockdep_is_held(lock)           lock_is_held(&(lock)->dep_map)
#define lockdep_is_held_type(lock, r)   lock_is_held_type(&(lock)->dep_map, (r))

extern void lock_set_class(struct lockdep_map *lock, const char *name,
                           struct lock_class_key *key, unsigned int subclass,
                           unsigned long ip);

static inline void lock_set_subclass(struct lockdep_map *lock,
                unsigned int subclass, unsigned long ip)
{
        lock_set_class(lock, lock->name, lock->key, subclass, ip);
}

extern void lock_downgrade(struct lockdep_map *lock, unsigned long ip);

#define NIL_COOKIE (struct pin_cookie){ .val = 0U, }

extern struct pin_cookie lock_pin_lock(struct lockdep_map *lock);
extern void lock_repin_lock(struct lockdep_map *lock, struct pin_cookie);
extern void lock_unpin_lock(struct lockdep_map *lock, struct pin_cookie);

#define lockdep_depth(tsk)      (debug_locks ? (tsk)->lockdep_depth : 0)

#define lockdep_assert_held(l)  do {                            \
                WARN_ON(debug_locks && !lockdep_is_held(l));    \
        } while (0)

#define lockdep_assert_held_write(l)    do {                    \
                WARN_ON(debug_locks && !lockdep_is_held_type(l, 0));    \
        } while (0)

#define lockdep_assert_held_read(l)     do {                            \
                WARN_ON(debug_locks && !lockdep_is_held_type(l, 1));    \
        } while (0)

#define lockdep_assert_held_once(l)     do {                            \
                WARN_ON_ONCE(debug_locks && !lockdep_is_held(l));       \
        } while (0)

#define lockdep_recursing(tsk)  ((tsk)->lockdep_recursion)

#define lockdep_pin_lock(l)     lock_pin_lock(&(l)->dep_map)
#define lockdep_repin_lock(l,c) lock_repin_lock(&(l)->dep_map, (c))
#define lockdep_unpin_lock(l,c) lock_unpin_lock(&(l)->dep_map, (c))

#else /* !CONFIG_LOCKDEP */

static inline void lockdep_init_task(struct task_struct *task)
{
}

static inline void lockdep_off(void)
{
}

static inline void lockdep_on(void)
{
}

static inline void lockdep_set_selftest_task(struct task_struct *task)
{
}

# define lock_acquire(l, s, t, r, c, n, i)      do { } while (0)
# define lock_release(l, i)                     do { } while (0)
# define lock_downgrade(l, i)                   do { } while (0)
# define lock_set_class(l, n, k, s, i)          do { } while (0)
# define lock_set_subclass(l, s, i)             do { } while (0)
# define lockdep_init()                         do { } while (0)
# define lockdep_init_map_waits(lock, name, key, sub, inner, outer) \
                do { (void)(name); (void)(key); } while (0)
# define lockdep_init_map_wait(lock, name, key, sub, inner) \
                do { (void)(name); (void)(key); } while (0)
# define lockdep_init_map(lock, name, key, sub) \
                do { (void)(name); (void)(key); } while (0)
# define lockdep_set_class(lock, key)           do { (void)(key); } while (0)
# define lockdep_set_class_and_name(lock, key, name) \
                do { (void)(key); (void)(name); } while (0)
#define lockdep_set_class_and_subclass(lock, key, sub) \
                do { (void)(key); } while (0)
#define lockdep_set_subclass(lock, sub)         do { } while (0)

#define lockdep_set_novalidate_class(lock) do { } while (0)

/*
 * We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP
 * case since the result is not well defined and the caller should rather
 * #ifdef the call himself.
 */

# define lockdep_reset()                do { debug_locks = 1; } while (0)
# define lockdep_free_key_range(start, size)    do { } while (0)
# define lockdep_sys_exit()                     do { } while (0)

static inline void lockdep_register_key(struct lock_class_key *key)
{
}

static inline void lockdep_unregister_key(struct lock_class_key *key)
{
}

#define lockdep_depth(tsk)      (0)

#define lockdep_is_held_type(l, r)              (1)

#define lockdep_assert_held(l)                  do { (void)(l); } while (0)
#define lockdep_assert_held_write(l)    do { (void)(l); } while (0)
#define lockdep_assert_held_read(l)             do { (void)(l); } while (0)
#define lockdep_assert_held_once(l)             do { (void)(l); } while (0)

#define lockdep_recursing(tsk)                  (0)

#define NIL_COOKIE (struct pin_cookie){ }

#define lockdep_pin_lock(l)                     ({ struct pin_cookie cookie = { }; cookie; })
#define lockdep_repin_lock(l, c)                do { (void)(l); (void)(c); } while (0)
#define lockdep_unpin_lock(l, c)                do { (void)(l); (void)(c); } while (0)

#endif /* !LOCKDEP */

enum xhlock_context_t {
        XHLOCK_HARD,
        XHLOCK_SOFT,
        XHLOCK_CTX_NR,
};

#define lockdep_init_map_crosslock(m, n, k, s) do {} while (0)
/*
 * To initialize a lockdep_map statically use this macro.
 * Note that _name must not be NULL.
 */
#define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
        { .name = (_name), .key = (void *)(_key), }

static inline void lockdep_invariant_state(bool force) {}
static inline void lockdep_free_task(struct task_struct *task) {}

#ifdef CONFIG_LOCK_STAT

extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
extern void lock_acquired(struct lockdep_map *lock, unsigned long ip);

#define LOCK_CONTENDED(_lock, try, lock)                        \
do {                                                            \
        if (!try(_lock)) {                                      \
                lock_contended(&(_lock)->dep_map, _RET_IP_);    \
                lock(_lock);                                    \
        }                                                       \
        lock_acquired(&(_lock)->dep_map, _RET_IP_);                     \
} while (0)

#define LOCK_CONTENDED_RETURN(_lock, try, lock)                 \
({                                                              \
        int ____err = 0;                                        \
        if (!try(_lock)) {                                      \
                lock_contended(&(_lock)->dep_map, _RET_IP_);    \
                ____err = lock(_lock);                          \
        }                                                       \
        if (!____err)                                           \
                lock_acquired(&(_lock)->dep_map, _RET_IP_);     \
        ____err;                                                \
})

#else /* CONFIG_LOCK_STAT */

#define lock_contended(lockdep_map, ip) do {} while (0)
#define lock_acquired(lockdep_map, ip) do {} while (0)

#define LOCK_CONTENDED(_lock, try, lock) \
        lock(_lock)

#define LOCK_CONTENDED_RETURN(_lock, try, lock) \
        lock(_lock)

#endif /* CONFIG_LOCK_STAT */

#ifdef CONFIG_LOCKDEP

/*
 * On lockdep we dont want the hand-coded irq-enable of
 * _raw_*_lock_flags() code, because lockdep assumes
 * that interrupts are not re-enabled during lock-acquire:
 */
#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
        LOCK_CONTENDED((_lock), (try), (lock))

#else /* CONFIG_LOCKDEP */

#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
        lockfl((_lock), (flags))

#endif /* CONFIG_LOCKDEP */

#ifdef CONFIG_PROVE_LOCKING
extern void print_irqtrace_events(struct task_struct *curr);
#else
static inline void print_irqtrace_events(struct task_struct *curr)
{
}
#endif

/* Variable used to make lockdep treat read_lock() as recursive in selftests */
#ifdef CONFIG_DEBUG_LOCKING_API_SELFTESTS
extern unsigned int force_read_lock_recursive;
#else /* CONFIG_DEBUG_LOCKING_API_SELFTESTS */
#define force_read_lock_recursive 0
#endif /* CONFIG_DEBUG_LOCKING_API_SELFTESTS */

#ifdef CONFIG_LOCKDEP
extern bool read_lock_is_recursive(void);
#else /* CONFIG_LOCKDEP */
/* If !LOCKDEP, the value is meaningless */
#define read_lock_is_recursive() 0
#endif

/*
 * For trivial one-depth nesting of a lock-class, the following
 * global define can be used. (Subsystems with multiple levels
 * of nesting should define their own lock-nesting subclasses.)
 */
#define SINGLE_DEPTH_NESTING                    1

/*
 * Map the dependency ops to NOP or to real lockdep ops, depending
 * on the per lock-class debug mode:
 */

#define lock_acquire_exclusive(l, s, t, n, i)           lock_acquire(l, s, t, 0, 1, n, i)
#define lock_acquire_shared(l, s, t, n, i)              lock_acquire(l, s, t, 1, 1, n, i)
#define lock_acquire_shared_recursive(l, s, t, n, i)    lock_acquire(l, s, t, 2, 1, n, i)

#define spin_acquire(l, s, t, i)                lock_acquire_exclusive(l, s, t, NULL, i)
#define spin_acquire_nest(l, s, t, n, i)        lock_acquire_exclusive(l, s, t, n, i)
#define spin_release(l, i)                      lock_release(l, i)

#define rwlock_acquire(l, s, t, i)              lock_acquire_exclusive(l, s, t, NULL, i)
#define rwlock_acquire_read(l, s, t, i)                                 \
do {                                                                    \
        if (read_lock_is_recursive())                                   \
                lock_acquire_shared_recursive(l, s, t, NULL, i);        \
        else                                                            \
                lock_acquire_shared(l, s, t, NULL, i);                  \
} while (0)

#define rwlock_release(l, i)                    lock_release(l, i)

#define seqcount_acquire(l, s, t, i)            lock_acquire_exclusive(l, s, t, NULL, i)
#define seqcount_acquire_read(l, s, t, i)       lock_acquire_shared_recursive(l, s, t, NULL, i)
#define seqcount_release(l, i)                  lock_release(l, i)

#define mutex_acquire(l, s, t, i)               lock_acquire_exclusive(l, s, t, NULL, i)
#define mutex_acquire_nest(l, s, t, n, i)       lock_acquire_exclusive(l, s, t, n, i)
#define mutex_release(l, i)                     lock_release(l, i)

#define rwsem_acquire(l, s, t, i)               lock_acquire_exclusive(l, s, t, NULL, i)
#define rwsem_acquire_nest(l, s, t, n, i)       lock_acquire_exclusive(l, s, t, n, i)
#define rwsem_acquire_read(l, s, t, i)          lock_acquire_shared(l, s, t, NULL, i)
#define rwsem_release(l, i)                     lock_release(l, i)

#define lock_map_acquire(l)                     lock_acquire_exclusive(l, 0, 0, NULL, _THIS_IP_)
#define lock_map_acquire_read(l)                lock_acquire_shared_recursive(l, 0, 0, NULL, _THIS_IP_)
#define lock_map_acquire_tryread(l)             lock_acquire_shared_recursive(l, 0, 1, NULL, _THIS_IP_)
#define lock_map_release(l)                     lock_release(l, _THIS_IP_)

#ifdef CONFIG_PROVE_LOCKING
# define might_lock(lock)                                               \
do {                                                                    \
        typecheck(struct lockdep_map *, &(lock)->dep_map);              \
        lock_acquire(&(lock)->dep_map, 0, 0, 0, 1, NULL, _THIS_IP_);    \
        lock_release(&(lock)->dep_map, _THIS_IP_);                      \
} while (0)
# define might_lock_read(lock)                                          \
do {                                                                    \
        typecheck(struct lockdep_map *, &(lock)->dep_map);              \
        lock_acquire(&(lock)->dep_map, 0, 0, 1, 1, NULL, _THIS_IP_);    \
        lock_release(&(lock)->dep_map, _THIS_IP_);                      \
} while (0)
# define might_lock_nested(lock, subclass)                              \
do {                                                                    \
        typecheck(struct lockdep_map *, &(lock)->dep_map);              \
        lock_acquire(&(lock)->dep_map, subclass, 0, 1, 1, NULL,         \
                     _THIS_IP_);                                        \
        lock_release(&(lock)->dep_map, _THIS_IP_);                      \
} while (0)

DECLARE_PER_CPU(int, hardirqs_enabled);
DECLARE_PER_CPU(int, hardirq_context);
DECLARE_PER_CPU(unsigned int, lockdep_recursion);

#define __lockdep_enabled       (debug_locks && !this_cpu_read(lockdep_recursion))

#define lockdep_assert_irqs_enabled()                                   \
do {                                                                    \
        WARN_ON_ONCE(__lockdep_enabled && !this_cpu_read(hardirqs_enabled)); \
} while (0)

#define lockdep_assert_irqs_disabled()                                  \
do {                                                                    \
        WARN_ON_ONCE(__lockdep_enabled && this_cpu_read(hardirqs_enabled)); \
} while (0)

#define lockdep_assert_in_irq()                                         \
do {                                                                    \
        WARN_ON_ONCE(__lockdep_enabled && !this_cpu_read(hardirq_context)); \
} while (0)

#define lockdep_assert_preemption_enabled()                             \
do {                                                                    \
        WARN_ON_ONCE(IS_ENABLED(CONFIG_PREEMPT_COUNT)   &&              \
                     __lockdep_enabled                  &&              \
                     (preempt_count() != 0              ||              \
                      !this_cpu_read(hardirqs_enabled)));               \
} while (0)

#define lockdep_assert_preemption_disabled()                            \
do {                                                                    \
        WARN_ON_ONCE(IS_ENABLED(CONFIG_PREEMPT_COUNT)   &&              \
                     __lockdep_enabled                  &&              \
                     (preempt_count() == 0              &&              \
                      this_cpu_read(hardirqs_enabled)));                \
} while (0)

#else
# define might_lock(lock) do { } while (0)
# define might_lock_read(lock) do { } while (0)
# define might_lock_nested(lock, subclass) do { } while (0)

# define lockdep_assert_irqs_enabled() do { } while (0)
# define lockdep_assert_irqs_disabled() do { } while (0)
# define lockdep_assert_in_irq() do { } while (0)

# define lockdep_assert_preemption_enabled() do { } while (0)
# define lockdep_assert_preemption_disabled() do { } while (0)
#endif

#ifdef CONFIG_PROVE_RAW_LOCK_NESTING

# define lockdep_assert_RT_in_threaded_ctx() do {                       \
                WARN_ONCE(debug_locks && !current->lockdep_recursion && \
                          lockdep_hardirq_context() &&                  \
                          !(current->hardirq_threaded || current->irq_config),  \
                          "Not in threaded context on PREEMPT_RT as expected\n");       \
} while (0)

#else

# define lockdep_assert_RT_in_threaded_ctx() do { } while (0)

#endif

#ifdef CONFIG_LOCKDEP
void lockdep_rcu_suspicious(const char *file, const int line, const char *s);
#else
static inline void
lockdep_rcu_suspicious(const char *file, const int line, const char *s)
{
}
#endif

#endif /* __LINUX_LOCKDEP_H */