554 lines
16 KiB
C
554 lines
16 KiB
C
/*
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* Runtime locking correctness validator
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*
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* Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
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* Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
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*
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* see Documentation/locking/lockdep-design.txt for more details.
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*/
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#ifndef __LINUX_LOCKDEP_H
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#define __LINUX_LOCKDEP_H
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struct task_struct;
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struct lockdep_map;
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/* for sysctl */
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extern int prove_locking;
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extern int lock_stat;
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#ifdef CONFIG_LOCKDEP
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#include <linux/linkage.h>
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#include <linux/list.h>
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#include <linux/debug_locks.h>
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#include <linux/stacktrace.h>
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/*
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* We'd rather not expose kernel/lockdep_states.h this wide, but we do need
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* the total number of states... :-(
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*/
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#define XXX_LOCK_USAGE_STATES (1+3*4)
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#define MAX_LOCKDEP_SUBCLASSES 8UL
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/*
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* NR_LOCKDEP_CACHING_CLASSES ... Number of classes
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* cached in the instance of lockdep_map
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*
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* Currently main class (subclass == 0) and signle depth subclass
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* are cached in lockdep_map. This optimization is mainly targeting
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* on rq->lock. double_rq_lock() acquires this highly competitive with
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* single depth.
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*/
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#define NR_LOCKDEP_CACHING_CLASSES 2
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/*
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* Lock-classes are keyed via unique addresses, by embedding the
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* lockclass-key into the kernel (or module) .data section. (For
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* static locks we use the lock address itself as the key.)
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*/
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struct lockdep_subclass_key {
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char __one_byte;
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} __attribute__ ((__packed__));
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struct lock_class_key {
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struct lockdep_subclass_key subkeys[MAX_LOCKDEP_SUBCLASSES];
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};
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extern struct lock_class_key __lockdep_no_validate__;
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#define LOCKSTAT_POINTS 4
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/*
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* The lock-class itself:
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*/
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struct lock_class {
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/*
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* class-hash:
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*/
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struct list_head hash_entry;
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/*
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* global list of all lock-classes:
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*/
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struct list_head lock_entry;
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struct lockdep_subclass_key *key;
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unsigned int subclass;
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unsigned int dep_gen_id;
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/*
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* IRQ/softirq usage tracking bits:
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*/
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unsigned long usage_mask;
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struct stack_trace usage_traces[XXX_LOCK_USAGE_STATES];
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/*
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* These fields represent a directed graph of lock dependencies,
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* to every node we attach a list of "forward" and a list of
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* "backward" graph nodes.
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*/
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struct list_head locks_after, locks_before;
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/*
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* Generation counter, when doing certain classes of graph walking,
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* to ensure that we check one node only once:
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*/
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unsigned int version;
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/*
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* Statistics counter:
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*/
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unsigned long ops;
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const char *name;
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int name_version;
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#ifdef CONFIG_LOCK_STAT
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unsigned long contention_point[LOCKSTAT_POINTS];
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unsigned long contending_point[LOCKSTAT_POINTS];
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#endif
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};
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#ifdef CONFIG_LOCK_STAT
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struct lock_time {
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s64 min;
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s64 max;
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s64 total;
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unsigned long nr;
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};
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enum bounce_type {
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bounce_acquired_write,
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bounce_acquired_read,
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bounce_contended_write,
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bounce_contended_read,
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nr_bounce_types,
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bounce_acquired = bounce_acquired_write,
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bounce_contended = bounce_contended_write,
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};
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struct lock_class_stats {
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unsigned long contention_point[LOCKSTAT_POINTS];
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unsigned long contending_point[LOCKSTAT_POINTS];
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struct lock_time read_waittime;
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struct lock_time write_waittime;
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struct lock_time read_holdtime;
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struct lock_time write_holdtime;
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unsigned long bounces[nr_bounce_types];
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};
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struct lock_class_stats lock_stats(struct lock_class *class);
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void clear_lock_stats(struct lock_class *class);
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#endif
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/*
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* Map the lock object (the lock instance) to the lock-class object.
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* This is embedded into specific lock instances:
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*/
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struct lockdep_map {
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struct lock_class_key *key;
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struct lock_class *class_cache[NR_LOCKDEP_CACHING_CLASSES];
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const char *name;
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#ifdef CONFIG_LOCK_STAT
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int cpu;
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unsigned long ip;
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#endif
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};
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static inline void lockdep_copy_map(struct lockdep_map *to,
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struct lockdep_map *from)
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{
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int i;
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*to = *from;
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/*
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* Since the class cache can be modified concurrently we could observe
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* half pointers (64bit arch using 32bit copy insns). Therefore clear
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* the caches and take the performance hit.
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*
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* XXX it doesn't work well with lockdep_set_class_and_subclass(), since
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* that relies on cache abuse.
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*/
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for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
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to->class_cache[i] = NULL;
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}
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/*
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* Every lock has a list of other locks that were taken after it.
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* We only grow the list, never remove from it:
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*/
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struct lock_list {
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struct list_head entry;
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struct lock_class *class;
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struct stack_trace trace;
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int distance;
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/*
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* The parent field is used to implement breadth-first search, and the
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* bit 0 is reused to indicate if the lock has been accessed in BFS.
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*/
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struct lock_list *parent;
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};
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/*
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* We record lock dependency chains, so that we can cache them:
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*/
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struct lock_chain {
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u8 irq_context;
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u8 depth;
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u16 base;
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struct list_head entry;
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u64 chain_key;
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};
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#define MAX_LOCKDEP_KEYS_BITS 13
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/*
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* Subtract one because we offset hlock->class_idx by 1 in order
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* to make 0 mean no class. This avoids overflowing the class_idx
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* bitfield and hitting the BUG in hlock_class().
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*/
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#define MAX_LOCKDEP_KEYS ((1UL << MAX_LOCKDEP_KEYS_BITS) - 1)
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struct held_lock {
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/*
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* One-way hash of the dependency chain up to this point. We
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* hash the hashes step by step as the dependency chain grows.
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*
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* We use it for dependency-caching and we skip detection
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* passes and dependency-updates if there is a cache-hit, so
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* it is absolutely critical for 100% coverage of the validator
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* to have a unique key value for every unique dependency path
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* that can occur in the system, to make a unique hash value
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* as likely as possible - hence the 64-bit width.
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*
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* The task struct holds the current hash value (initialized
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* with zero), here we store the previous hash value:
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*/
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u64 prev_chain_key;
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unsigned long acquire_ip;
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struct lockdep_map *instance;
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struct lockdep_map *nest_lock;
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#ifdef CONFIG_LOCK_STAT
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u64 waittime_stamp;
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u64 holdtime_stamp;
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#endif
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unsigned int class_idx:MAX_LOCKDEP_KEYS_BITS;
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/*
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* The lock-stack is unified in that the lock chains of interrupt
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* contexts nest ontop of process context chains, but we 'separate'
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* the hashes by starting with 0 if we cross into an interrupt
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* context, and we also keep do not add cross-context lock
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* dependencies - the lock usage graph walking covers that area
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* anyway, and we'd just unnecessarily increase the number of
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* dependencies otherwise. [Note: hardirq and softirq contexts
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* are separated from each other too.]
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*
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* The following field is used to detect when we cross into an
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* interrupt context:
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*/
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unsigned int irq_context:2; /* bit 0 - soft, bit 1 - hard */
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unsigned int trylock:1; /* 16 bits */
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unsigned int read:2; /* see lock_acquire() comment */
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unsigned int check:1; /* see lock_acquire() comment */
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unsigned int hardirqs_off:1;
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unsigned int references:12; /* 32 bits */
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unsigned int pin_count;
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};
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/*
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* Initialization, self-test and debugging-output methods:
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*/
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extern void lockdep_init(void);
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extern void lockdep_info(void);
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extern void lockdep_reset(void);
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extern void lockdep_reset_lock(struct lockdep_map *lock);
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extern void lockdep_free_key_range(void *start, unsigned long size);
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extern asmlinkage void lockdep_sys_exit(void);
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extern void lockdep_off(void);
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extern void lockdep_on(void);
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/*
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* These methods are used by specific locking variants (spinlocks,
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* rwlocks, mutexes and rwsems) to pass init/acquire/release events
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* to lockdep:
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*/
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extern void lockdep_init_map(struct lockdep_map *lock, const char *name,
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struct lock_class_key *key, int subclass);
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/*
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* To initialize a lockdep_map statically use this macro.
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* Note that _name must not be NULL.
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*/
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#define STATIC_LOCKDEP_MAP_INIT(_name, _key) \
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{ .name = (_name), .key = (void *)(_key), }
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/*
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* Reinitialize a lock key - for cases where there is special locking or
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* special initialization of locks so that the validator gets the scope
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* of dependencies wrong: they are either too broad (they need a class-split)
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* or they are too narrow (they suffer from a false class-split):
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*/
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#define lockdep_set_class(lock, key) \
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lockdep_init_map(&(lock)->dep_map, #key, key, 0)
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#define lockdep_set_class_and_name(lock, key, name) \
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lockdep_init_map(&(lock)->dep_map, name, key, 0)
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#define lockdep_set_class_and_subclass(lock, key, sub) \
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lockdep_init_map(&(lock)->dep_map, #key, key, sub)
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#define lockdep_set_subclass(lock, sub) \
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lockdep_init_map(&(lock)->dep_map, #lock, \
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(lock)->dep_map.key, sub)
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#define lockdep_set_novalidate_class(lock) \
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lockdep_set_class_and_name(lock, &__lockdep_no_validate__, #lock)
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/*
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* Compare locking classes
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*/
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#define lockdep_match_class(lock, key) lockdep_match_key(&(lock)->dep_map, key)
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static inline int lockdep_match_key(struct lockdep_map *lock,
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struct lock_class_key *key)
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{
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return lock->key == key;
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}
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/*
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* Acquire a lock.
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*
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* Values for "read":
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*
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* 0: exclusive (write) acquire
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* 1: read-acquire (no recursion allowed)
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* 2: read-acquire with same-instance recursion allowed
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*
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* Values for check:
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*
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* 0: simple checks (freeing, held-at-exit-time, etc.)
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* 1: full validation
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*/
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extern void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
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int trylock, int read, int check,
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struct lockdep_map *nest_lock, unsigned long ip);
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extern void lock_release(struct lockdep_map *lock, int nested,
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unsigned long ip);
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#define lockdep_is_held(lock) lock_is_held(&(lock)->dep_map)
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extern int lock_is_held(struct lockdep_map *lock);
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extern void lock_set_class(struct lockdep_map *lock, const char *name,
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struct lock_class_key *key, unsigned int subclass,
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unsigned long ip);
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static inline void lock_set_subclass(struct lockdep_map *lock,
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unsigned int subclass, unsigned long ip)
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{
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lock_set_class(lock, lock->name, lock->key, subclass, ip);
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}
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extern void lockdep_set_current_reclaim_state(gfp_t gfp_mask);
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extern void lockdep_clear_current_reclaim_state(void);
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extern void lockdep_trace_alloc(gfp_t mask);
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extern void lock_pin_lock(struct lockdep_map *lock);
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extern void lock_unpin_lock(struct lockdep_map *lock);
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# define INIT_LOCKDEP .lockdep_recursion = 0, .lockdep_reclaim_gfp = 0,
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#define lockdep_depth(tsk) (debug_locks ? (tsk)->lockdep_depth : 0)
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#define lockdep_assert_held(l) do { \
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WARN_ON(debug_locks && !lockdep_is_held(l)); \
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} while (0)
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#define lockdep_assert_held_once(l) do { \
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WARN_ON_ONCE(debug_locks && !lockdep_is_held(l)); \
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} while (0)
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#define lockdep_recursing(tsk) ((tsk)->lockdep_recursion)
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#define lockdep_pin_lock(l) lock_pin_lock(&(l)->dep_map)
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#define lockdep_unpin_lock(l) lock_unpin_lock(&(l)->dep_map)
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#else /* !CONFIG_LOCKDEP */
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static inline void lockdep_off(void)
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{
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}
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static inline void lockdep_on(void)
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{
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}
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# define lock_acquire(l, s, t, r, c, n, i) do { } while (0)
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# define lock_release(l, n, i) do { } while (0)
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# define lock_set_class(l, n, k, s, i) do { } while (0)
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# define lock_set_subclass(l, s, i) do { } while (0)
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# define lockdep_set_current_reclaim_state(g) do { } while (0)
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# define lockdep_clear_current_reclaim_state() do { } while (0)
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# define lockdep_trace_alloc(g) do { } while (0)
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# define lockdep_init() do { } while (0)
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# define lockdep_info() do { } while (0)
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# define lockdep_init_map(lock, name, key, sub) \
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do { (void)(name); (void)(key); } while (0)
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# define lockdep_set_class(lock, key) do { (void)(key); } while (0)
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# define lockdep_set_class_and_name(lock, key, name) \
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do { (void)(key); (void)(name); } while (0)
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#define lockdep_set_class_and_subclass(lock, key, sub) \
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do { (void)(key); } while (0)
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#define lockdep_set_subclass(lock, sub) do { } while (0)
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#define lockdep_set_novalidate_class(lock) do { } while (0)
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/*
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* We don't define lockdep_match_class() and lockdep_match_key() for !LOCKDEP
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* case since the result is not well defined and the caller should rather
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* #ifdef the call himself.
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*/
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# define INIT_LOCKDEP
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# define lockdep_reset() do { debug_locks = 1; } while (0)
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# define lockdep_free_key_range(start, size) do { } while (0)
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# define lockdep_sys_exit() do { } while (0)
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/*
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* The class key takes no space if lockdep is disabled:
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*/
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struct lock_class_key { };
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#define lockdep_depth(tsk) (0)
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#define lockdep_assert_held(l) do { (void)(l); } while (0)
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#define lockdep_assert_held_once(l) do { (void)(l); } while (0)
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#define lockdep_recursing(tsk) (0)
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#define lockdep_pin_lock(l) do { (void)(l); } while (0)
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#define lockdep_unpin_lock(l) do { (void)(l); } while (0)
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#endif /* !LOCKDEP */
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#ifdef CONFIG_LOCK_STAT
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extern void lock_contended(struct lockdep_map *lock, unsigned long ip);
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extern void lock_acquired(struct lockdep_map *lock, unsigned long ip);
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#define LOCK_CONTENDED(_lock, try, lock) \
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do { \
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if (!try(_lock)) { \
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lock_contended(&(_lock)->dep_map, _RET_IP_); \
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lock(_lock); \
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} \
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lock_acquired(&(_lock)->dep_map, _RET_IP_); \
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} while (0)
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#else /* CONFIG_LOCK_STAT */
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#define lock_contended(lockdep_map, ip) do {} while (0)
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#define lock_acquired(lockdep_map, ip) do {} while (0)
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#define LOCK_CONTENDED(_lock, try, lock) \
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lock(_lock)
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#endif /* CONFIG_LOCK_STAT */
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#ifdef CONFIG_LOCKDEP
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/*
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* On lockdep we dont want the hand-coded irq-enable of
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* _raw_*_lock_flags() code, because lockdep assumes
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* that interrupts are not re-enabled during lock-acquire:
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*/
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#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
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LOCK_CONTENDED((_lock), (try), (lock))
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#else /* CONFIG_LOCKDEP */
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#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
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lockfl((_lock), (flags))
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#endif /* CONFIG_LOCKDEP */
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#ifdef CONFIG_TRACE_IRQFLAGS
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extern void print_irqtrace_events(struct task_struct *curr);
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#else
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static inline void print_irqtrace_events(struct task_struct *curr)
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{
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}
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#endif
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/*
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* For trivial one-depth nesting of a lock-class, the following
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* global define can be used. (Subsystems with multiple levels
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* of nesting should define their own lock-nesting subclasses.)
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*/
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#define SINGLE_DEPTH_NESTING 1
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/*
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* Map the dependency ops to NOP or to real lockdep ops, depending
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* on the per lock-class debug mode:
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*/
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#define lock_acquire_exclusive(l, s, t, n, i) lock_acquire(l, s, t, 0, 1, n, i)
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#define lock_acquire_shared(l, s, t, n, i) lock_acquire(l, s, t, 1, 1, n, i)
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#define lock_acquire_shared_recursive(l, s, t, n, i) lock_acquire(l, s, t, 2, 1, n, i)
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#define spin_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
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#define spin_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
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#define spin_release(l, n, i) lock_release(l, n, i)
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#define rwlock_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
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#define rwlock_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i)
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#define rwlock_release(l, n, i) lock_release(l, n, i)
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#define seqcount_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
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#define seqcount_acquire_read(l, s, t, i) lock_acquire_shared_recursive(l, s, t, NULL, i)
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#define seqcount_release(l, n, i) lock_release(l, n, i)
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#define mutex_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
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#define mutex_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
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#define mutex_release(l, n, i) lock_release(l, n, i)
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#define rwsem_acquire(l, s, t, i) lock_acquire_exclusive(l, s, t, NULL, i)
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#define rwsem_acquire_nest(l, s, t, n, i) lock_acquire_exclusive(l, s, t, n, i)
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#define rwsem_acquire_read(l, s, t, i) lock_acquire_shared(l, s, t, NULL, i)
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#define rwsem_release(l, n, i) lock_release(l, n, i)
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#define lock_map_acquire(l) lock_acquire_exclusive(l, 0, 0, NULL, _THIS_IP_)
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#define lock_map_acquire_read(l) lock_acquire_shared_recursive(l, 0, 0, NULL, _THIS_IP_)
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#define lock_map_acquire_tryread(l) lock_acquire_shared_recursive(l, 0, 1, NULL, _THIS_IP_)
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#define lock_map_release(l) lock_release(l, 1, _THIS_IP_)
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#ifdef CONFIG_PROVE_LOCKING
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# define might_lock(lock) \
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do { \
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typecheck(struct lockdep_map *, &(lock)->dep_map); \
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lock_acquire(&(lock)->dep_map, 0, 0, 0, 1, NULL, _THIS_IP_); \
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lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
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} while (0)
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# define might_lock_read(lock) \
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do { \
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typecheck(struct lockdep_map *, &(lock)->dep_map); \
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lock_acquire(&(lock)->dep_map, 0, 0, 1, 1, NULL, _THIS_IP_); \
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lock_release(&(lock)->dep_map, 0, _THIS_IP_); \
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} while (0)
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#else
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# define might_lock(lock) do { } while (0)
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# define might_lock_read(lock) do { } while (0)
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#endif
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#ifdef CONFIG_LOCKDEP
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void lockdep_rcu_suspicious(const char *file, const int line, const char *s);
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#else
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static inline void
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lockdep_rcu_suspicious(const char *file, const int line, const char *s)
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{
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}
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#endif
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#endif /* __LINUX_LOCKDEP_H */
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