text: /*
   * kernel/lockdep_proc.c
   *
   * Runtime locking correctness validator
   *
   * Started by Ingo Molnar:
   *
   *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
   *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
   *
   * Code for /proc/lockdep and /proc/lockdep_stats:
   *
   */
  #include <linux/module.h>
  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>
  #include <linux/kallsyms.h>
  #include <linux/debug_locks.h>
  #include <linux/vmalloc.h>
  #include <linux/sort.h>
  #include <asm/uaccess.h>
  #include <asm/div64.h>
  
  #include "lockdep_internals.h"
  
  static void *l_next(struct seq_file *m, void *v, loff_t *pos)
  {
  	return seq_list_next(v, &all_lock_classes, pos);
  }
  
  static void *l_start(struct seq_file *m, loff_t *pos)
  {
  	return seq_list_start_head(&all_lock_classes, *pos);
  }
  
  static void l_stop(struct seq_file *m, void *v)
  {
  }
  
  static void print_name(struct seq_file *m, struct lock_class *class)
  {
  	char str[128];
  	const char *name = class->name;
  
  	if (!name) {
  		name = __get_key_name(class->key, str);
  		seq_printf(m, "%s", name);
  	} else{
  		seq_printf(m, "%s", name);
  		if (class->name_version > 1)
  			seq_printf(m, "#%d", class->name_version);
  		if (class->subclass)
  			seq_printf(m, "/%d", class->subclass);
  	}
  }
  
  static int l_show(struct seq_file *m, void *v)
  {
  	struct lock_class *class = list_entry(v, struct lock_class, lock_entry);
  	struct lock_list *entry;
  	char usage[LOCK_USAGE_CHARS];
  
  	if (v == &all_lock_classes) {
  		seq_printf(m, "all lock classes:\n");
  		return 0;
  	}
  
  	seq_printf(m, "%p", class->key);
  #ifdef CONFIG_DEBUG_LOCKDEP
  	seq_printf(m, " OPS:%8ld", class->ops);
  #endif
  #ifdef CONFIG_PROVE_LOCKING
  	seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
  	seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
  #endif
  
  	get_usage_chars(class, usage);
  	seq_printf(m, " %s", usage);
  
  	seq_printf(m, ": ");
  	print_name(m, class);
  	seq_puts(m, "\n");
  
  	list_for_each_entry(entry, &class->locks_after, entry) {
  		if (entry->distance == 1) {
  			seq_printf(m, " -> [%p] ", entry->class->key);
  			print_name(m, entry->class);
  			seq_puts(m, "\n");
  		}
  	}
  	seq_puts(m, "\n");
  
  	return 0;
  }
  
  static const struct seq_operations lockdep_ops = {
  	.start	= l_start,
  	.next	= l_next,
  	.stop	= l_stop,
  	.show	= l_show,
  };
  
  static int lockdep_open(struct inode *inode, struct file *file)
  {
  	return seq_open(file, &lockdep_ops);
  }
  
  static const struct file_operations proc_lockdep_operations = {
  	.open		= lockdep_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= seq_release,
  };
  
  #ifdef CONFIG_PROVE_LOCKING
  static void *lc_start(struct seq_file *m, loff_t *pos)
  {
  	if (*pos == 0)
  		return SEQ_START_TOKEN;
  
  	if (*pos - 1 < nr_lock_chains)
  		return lock_chains + (*pos - 1);
  
  	return NULL;
  }
  
  static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
  {
  	(*pos)++;
  	return lc_start(m, pos);
  }
  
  static void lc_stop(struct seq_file *m, void *v)
  {
  }
  
  static int lc_show(struct seq_file *m, void *v)
  {
  	struct lock_chain *chain = v;
  	struct lock_class *class;
  	int i;
  
  	if (v == SEQ_START_TOKEN) {
  		seq_printf(m, "all lock chains:\n");
  		return 0;
  	}
  
  	seq_printf(m, "irq_context: %d\n", chain->irq_context);
  
  	for (i = 0; i < chain->depth; i++) {
  		class = lock_chain_get_class(chain, i);
  		if (!class->key)
  			continue;
  
  		seq_printf(m, "[%p] ", class->key);
  		print_name(m, class);
  		seq_puts(m, "\n");
  	}
  	seq_puts(m, "\n");
  
  	return 0;
  }
  
  static const struct seq_operations lockdep_chains_ops = {
  	.start	= lc_start,
  	.next	= lc_next,
  	.stop	= lc_stop,
  	.show	= lc_show,
  };
  
  static int lockdep_chains_open(struct inode *inode, struct file *file)
  {
  	return seq_open(file, &lockdep_chains_ops);
  }
  
  static const struct file_operations proc_lockdep_chains_operations = {
  	.open		= lockdep_chains_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= seq_release,
  };
  #endif /* CONFIG_PROVE_LOCKING */
  
  static void lockdep_stats_debug_show(struct seq_file *m)
  {
  #ifdef CONFIG_DEBUG_LOCKDEP
  	unsigned long long hi1 = debug_atomic_read(hardirqs_on_events),
  			   hi2 = debug_atomic_read(hardirqs_off_events),
  			   hr1 = debug_atomic_read(redundant_hardirqs_on),
  			   hr2 = debug_atomic_read(redundant_hardirqs_off),
  			   si1 = debug_atomic_read(softirqs_on_events),
  			   si2 = debug_atomic_read(softirqs_off_events),
  			   sr1 = debug_atomic_read(redundant_softirqs_on),
  			   sr2 = debug_atomic_read(redundant_softirqs_off);
  
  	seq_printf(m, " chain lookup misses:           %11llu\n",
  		debug_atomic_read(chain_lookup_misses));
  	seq_printf(m, " chain lookup hits:             %11llu\n",
  		debug_atomic_read(chain_lookup_hits));
  	seq_printf(m, " cyclic checks:                 %11llu\n",
  		debug_atomic_read(nr_cyclic_checks));
  	seq_printf(m, " find-mask forwards checks:     %11llu\n",
  		debug_atomic_read(nr_find_usage_forwards_checks));
  	seq_printf(m, " find-mask backwards checks:    %11llu\n",
  		debug_atomic_read(nr_find_usage_backwards_checks));
  
  	seq_printf(m, " hardirq on events:             %11llu\n", hi1);
  	seq_printf(m, " hardirq off events:            %11llu\n", hi2);
  	seq_printf(m, " redundant hardirq ons:         %11llu\n", hr1);
  	seq_printf(m, " redundant hardirq offs:        %11llu\n", hr2);
  	seq_printf(m, " softirq on events:             %11llu\n", si1);
  	seq_printf(m, " softirq off events:            %11llu\n", si2);
  	seq_printf(m, " redundant softirq ons:         %11llu\n", sr1);
  	seq_printf(m, " redundant softirq offs:        %11llu\n", sr2);
  #endif
  }
  
  static int lockdep_stats_show(struct seq_file *m, void *v)
  {
  	struct lock_class *class;
  	unsigned long nr_unused = 0, nr_uncategorized = 0,
  		      nr_irq_safe = 0, nr_irq_unsafe = 0,
  		      nr_softirq_safe = 0, nr_softirq_unsafe = 0,
  		      nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
  		      nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
  		      nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
  		      nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
  		      sum_forward_deps = 0;
  
  	list_for_each_entry(class, &all_lock_classes, lock_entry) {
  
  		if (class->usage_mask == 0)
  			nr_unused++;
  		if (class->usage_mask == LOCKF_USED)
  			nr_uncategorized++;
  		if (class->usage_mask & LOCKF_USED_IN_IRQ)
  			nr_irq_safe++;
  		if (class->usage_mask & LOCKF_ENABLED_IRQ)
  			nr_irq_unsafe++;
  		if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
  			nr_softirq_safe++;
  		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
  			nr_softirq_unsafe++;
  		if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
  			nr_hardirq_safe++;
  		if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
  			nr_hardirq_unsafe++;
  		if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
  			nr_irq_read_safe++;
  		if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
  			nr_irq_read_unsafe++;
  		if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
  			nr_softirq_read_safe++;
  		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
  			nr_softirq_read_unsafe++;
  		if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
  			nr_hardirq_read_safe++;
  		if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
  			nr_hardirq_read_unsafe++;
  
  #ifdef CONFIG_PROVE_LOCKING
  		sum_forward_deps += lockdep_count_forward_deps(class);
  #endif
  	}
  #ifdef CONFIG_DEBUG_LOCKDEP
  	DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
  #endif
  	seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
  			nr_lock_classes, MAX_LOCKDEP_KEYS);
  	seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
  			nr_list_entries, MAX_LOCKDEP_ENTRIES);
  	seq_printf(m, " indirect dependencies:         %11lu\n",
  			sum_forward_deps);
  
  	/*
  	 * Total number of dependencies:
  	 *
  	 * All irq-safe locks may nest inside irq-unsafe locks,
  	 * plus all the other known dependencies:
  	 */
  	seq_printf(m, " all direct dependencies:       %11lu\n",
  			nr_irq_unsafe * nr_irq_safe +
  			nr_hardirq_unsafe * nr_hardirq_safe +
  			nr_list_entries);
  
  #ifdef CONFIG_PROVE_LOCKING
  	seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
  			nr_lock_chains, MAX_LOCKDEP_CHAINS);
  	seq_printf(m, " dependency chain hlocks:       %11d [max: %lu]\n",
  			nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
  #endif
  
  #ifdef CONFIG_TRACE_IRQFLAGS
  	seq_printf(m, " in-hardirq chains:             %11u\n",
  			nr_hardirq_chains);
  	seq_printf(m, " in-softirq chains:             %11u\n",
  			nr_softirq_chains);
  #endif
  	seq_printf(m, " in-process chains:             %11u\n",
  			nr_process_chains);
  	seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
  			nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
  	seq_printf(m, " combined max dependencies:     %11u\n",
  			(nr_hardirq_chains + 1) *
  			(nr_softirq_chains + 1) *
  			(nr_process_chains + 1)
  	);
  	seq_printf(m, " hardirq-safe locks:            %11lu\n",
  			nr_hardirq_safe);
  	seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
  			nr_hardirq_unsafe);
  	seq_printf(m, " softirq-safe locks:            %11lu\n",
  			nr_softirq_safe);
  	seq_printf(m, " softirq-unsafe locks:          %11lu\n",
  			nr_softirq_unsafe);
  	seq_printf(m, " irq-safe locks:                %11lu\n",
  			nr_irq_safe);
  	seq_printf(m, " irq-unsafe locks:              %11lu\n",
  			nr_irq_unsafe);
  
  	seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
  			nr_hardirq_read_safe);
  	seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
  			nr_hardirq_read_unsafe);
  	seq_printf(m, " softirq-read-safe locks:       %11lu\n",
  			nr_softirq_read_safe);
  	seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
  			nr_softirq_read_unsafe);
  	seq_printf(m, " irq-read-safe locks:           %11lu\n",
  			nr_irq_read_safe);
  	seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
  			nr_irq_read_unsafe);
  
  	seq_printf(m, " uncategorized locks:           %11lu\n",
  			nr_uncategorized);
  	seq_printf(m, " unused locks:                  %11lu\n",
  			nr_unused);
  	seq_printf(m, " max locking depth:             %11u\n",
  			max_lockdep_depth);
  #ifdef CONFIG_PROVE_LOCKING
  	seq_printf(m, " max bfs queue depth:           %11u\n",
  			max_bfs_queue_depth);
  #endif
  	lockdep_stats_debug_show(m);
  	seq_printf(m, " debug_locks:                   %11u\n",
  			debug_locks);
  
  	return 0;
  }
  
  static int lockdep_stats_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, lockdep_stats_show, NULL);
  }
  
  static const struct file_operations proc_lockdep_stats_operations = {
  	.open		= lockdep_stats_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= single_release,
  };
  
  #ifdef CONFIG_LOCK_STAT
  
  struct lock_stat_data {
  	struct lock_class *class;
  	struct lock_class_stats stats;
  };
  
  struct lock_stat_seq {
  	struct lock_stat_data *iter_end;
  	struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
  };
  
  /*
   * sort on absolute number of contentions
   */
  static int lock_stat_cmp(const void *l, const void *r)
  {
  	const struct lock_stat_data *dl = l, *dr = r;
  	unsigned long nl, nr;
  
  	nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
  	nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
  
  	return nr - nl;
  }
  
  static void seq_line(struct seq_file *m, char c, int offset, int length)
  {
  	int i;
  
  	for (i = 0; i < offset; i++)
  		seq_puts(m, " ");
  	for (i = 0; i < length; i++)
  		seq_printf(m, "%c", c);
  	seq_puts(m, "\n");
  }
  
  static void snprint_time(char *buf, size_t bufsiz, s64 nr)
  {
  	s64 div;
  	s32 rem;
  
  	nr += 5; /* for display rounding */
  	div = div_s64_rem(nr, 1000, &rem);
  	snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
  }
  
  static void seq_time(struct seq_file *m, s64 time)
  {
  	char num[15];
  
  	snprint_time(num, sizeof(num), time);
  	seq_printf(m, " %14s", num);
  }
  
  static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
  {
  	seq_printf(m, "%14lu", lt->nr);
  	seq_time(m, lt->min);
  	seq_time(m, lt->max);
  	seq_time(m, lt->total);
  }
  
  static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
  {
  	char name[39];
  	struct lock_class *class;
  	struct lock_class_stats *stats;
  	int i, namelen;
  
  	class = data->class;
  	stats = &data->stats;
  
  	namelen = 38;
  	if (class->name_version > 1)
  		namelen -= 2; /* XXX truncates versions > 9 */
  	if (class->subclass)
  		namelen -= 2;
  
  	if (!class->name) {
  		char str[KSYM_NAME_LEN];
  		const char *key_name;
  
  		key_name = __get_key_name(class->key, str);
  		snprintf(name, namelen, "%s", key_name);
  	} else {
  		snprintf(name, namelen, "%s", class->name);
  	}
  	namelen = strlen(name);
  	if (class->name_version > 1) {
  		snprintf(name+namelen, 3, "#%d", class->name_version);
  		namelen += 2;
  	}
  	if (class->subclass) {
  		snprintf(name+namelen, 3, "/%d", class->subclass);
  		namelen += 2;
  	}
  
  	if (stats->write_holdtime.nr) {
  		if (stats->read_holdtime.nr)
  			seq_printf(m, "%38s-W:", name);
  		else
  			seq_printf(m, "%40s:", name);
  
  		seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
  		seq_lock_time(m, &stats->write_waittime);
  		seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
  		seq_lock_time(m, &stats->write_holdtime);
  		seq_puts(m, "\n");
  	}
  
  	if (stats->read_holdtime.nr) {
  		seq_printf(m, "%38s-R:", name);
  		seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
  		seq_lock_time(m, &stats->read_waittime);
  		seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
  		seq_lock_time(m, &stats->read_holdtime);
  		seq_puts(m, "\n");
  	}
  
  	if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
  		return;
  
  	if (stats->read_holdtime.nr)
  		namelen += 2;
  
  	for (i = 0; i < LOCKSTAT_POINTS; i++) {
  		char ip[32];
  
  		if (class->contention_point[i] == 0)
  			break;
  
  		if (!i)
  			seq_line(m, '-', 40-namelen, namelen);
  
  		snprintf(ip, sizeof(ip), "[<%p>]",
  				(void *)class->contention_point[i]);
  		seq_printf(m, "%40s %14lu %29s %pS\n",
  			   name, stats->contention_point[i],
  			   ip, (void *)class->contention_point[i]);
  	}
  	for (i = 0; i < LOCKSTAT_POINTS; i++) {
  		char ip[32];
  
  		if (class->contending_point[i] == 0)
  			break;
  
  		if (!i)
  			seq_line(m, '-', 40-namelen, namelen);
  
  		snprintf(ip, sizeof(ip), "[<%p>]",
  				(void *)class->contending_point[i]);
  		seq_printf(m, "%40s %14lu %29s %pS\n",
  			   name, stats->contending_point[i],
  			   ip, (void *)class->contending_point[i]);
  	}
  	if (i) {
  		seq_puts(m, "\n");
  		seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
  		seq_puts(m, "\n");
  	}
  }
  
  static void seq_header(struct seq_file *m)
  {
  	seq_printf(m, "lock_stat version 0.3\n");
  
  	if (unlikely(!debug_locks))
  		seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
  
  	seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
  	seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
  			"%14s %14s\n",
  			"class name",
  			"con-bounces",
  			"contentions",
  			"waittime-min",
  			"waittime-max",
  			"waittime-total",
  			"acq-bounces",
  			"acquisitions",
  			"holdtime-min",
  			"holdtime-max",
  			"holdtime-total");
  	seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
  	seq_printf(m, "\n");
  }
  
  static void *ls_start(struct seq_file *m, loff_t *pos)
  {
  	struct lock_stat_seq *data = m->private;
  	struct lock_stat_data *iter;
  
  	if (*pos == 0)
  		return SEQ_START_TOKEN;
  
  	iter = data->stats + (*pos - 1);
  	if (iter >= data->iter_end)
  		iter = NULL;
  
  	return iter;
  }
  
  static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
  {
  	(*pos)++;
  	return ls_start(m, pos);
  }
  
  static void ls_stop(struct seq_file *m, void *v)
  {
  }
  
  static int ls_show(struct seq_file *m, void *v)
  {
  	if (v == SEQ_START_TOKEN)
  		seq_header(m);
  	else
  		seq_stats(m, v);
  
  	return 0;
  }
  
  static const struct seq_operations lockstat_ops = {
  	.start	= ls_start,
  	.next	= ls_next,
  	.stop	= ls_stop,
  	.show	= ls_show,
  };
  
  static int lock_stat_open(struct inode *inode, struct file *file)
  {
  	int res;
  	struct lock_class *class;
  	struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
  
  	if (!data)
  		return -ENOMEM;
  
  	res = seq_open(file, &lockstat_ops);
  	if (!res) {
  		struct lock_stat_data *iter = data->stats;
  		struct seq_file *m = file->private_data;
  
  		list_for_each_entry(class, &all_lock_classes, lock_entry) {
  			iter->class = class;
  			iter->stats = lock_stats(class);
  			iter++;
  		}
  		data->iter_end = iter;
  
  		sort(data->stats, data->iter_end - data->stats,
  				sizeof(struct lock_stat_data),
  				lock_stat_cmp, NULL);
  
  		m->private = data;
  	} else
  		vfree(data);
  
  	return res;
  }
  
  static ssize_t lock_stat_write(struct file *file, const char __user *buf,
  			       size_t count, loff_t *ppos)
  {
  	struct lock_class *class;
  	char c;
  
  	if (count) {
  		if (get_user(c, buf))
  			return -EFAULT;
  
  		if (c != '0')
  			return count;
  
  		list_for_each_entry(class, &all_lock_classes, lock_entry)
  			clear_lock_stats(class);
  	}
  	return count;
  }
  
  static int lock_stat_release(struct inode *inode, struct file *file)
  {
  	struct seq_file *seq = file->private_data;
  
  	vfree(seq->private);
  	return seq_release(inode, file);
  }
  
  static const struct file_operations proc_lock_stat_operations = {
  	.open		= lock_stat_open,
  	.write		= lock_stat_write,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= lock_stat_release,
  };
  #endif /* CONFIG_LOCK_STAT */
  
  static int __init lockdep_proc_init(void)
  {
  	proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
  #ifdef CONFIG_PROVE_LOCKING
  	proc_create("lockdep_chains", S_IRUSR, NULL,
  		    &proc_lockdep_chains_operations);
  #endif
  	proc_create("lockdep_stats", S_IRUSR, NULL,
  		    &proc_lockdep_stats_operations);
  
  #ifdef CONFIG_LOCK_STAT
  	proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL,
  		    &proc_lock_stat_operations);
  #endif
  
  	return 0;
  }
  
  __initcall(lockdep_proc_init);
  