/*
   * Read-Copy Update tracing for classic implementation
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
   *
   * Copyright IBM Corporation, 2008
   *
   * Papers:  http://www.rdrop.com/users/paulmck/RCU
   *
   * For detailed explanation of Read-Copy Update mechanism see -

   *		Documentation/RCU

   *
   */
  #include <linux/types.h>
  #include <linux/kernel.h>
  #include <linux/init.h>
  #include <linux/spinlock.h>
  #include <linux/smp.h>
  #include <linux/rcupdate.h>
  #include <linux/interrupt.h>
  #include <linux/sched.h>

  #include <linux/atomic.h>

  #include <linux/bitops.h>
  #include <linux/module.h>
  #include <linux/completion.h>
  #include <linux/moduleparam.h>
  #include <linux/percpu.h>
  #include <linux/notifier.h>
  #include <linux/cpu.h>
  #include <linux/mutex.h>
  #include <linux/debugfs.h>
  #include <linux/seq_file.h>

  #define RCU_TREE_NONCORE

  #include "rcutree.h"

  #ifdef CONFIG_RCU_BOOST

  DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status);

  DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_cpu);

  DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops);

  DECLARE_PER_CPU(char, rcu_cpu_has_work);
  
  static char convert_kthread_status(unsigned int kthread_status)
  {
  	if (kthread_status > RCU_KTHREAD_MAX)
  		return '?';

  	return "SRWOY"[kthread_status];

  }

  #endif /* #ifdef CONFIG_RCU_BOOST */

  static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
  {
  	if (!rdp->beenonline)
  		return;

  	seq_printf(m, "%3d%cc=%lu g=%lu pq=%d pqc=%lu qp=%d",

  		   rdp->cpu,
  		   cpu_is_offline(rdp->cpu) ? '!' : ' ',
  		   rdp->completed, rdp->gpnum,
  		   rdp->passed_quiesc, rdp->passed_quiesc_completed,

  		   rdp->qs_pending);

  #ifdef CONFIG_NO_HZ

  	seq_printf(m, " dt=%d/%d/%d df=%lu",
  		   atomic_read(&rdp->dynticks->dynticks),

  		   rdp->dynticks->dynticks_nesting,

  		   rdp->dynticks->dynticks_nmi_nesting,

  		   rdp->dynticks_fqs);
  #endif /* #ifdef CONFIG_NO_HZ */
  	seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi);

  	seq_printf(m, " ql=%ld qs=%c%c%c%c",

  		   rdp->qlen,
  		   ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
  			rdp->nxttail[RCU_NEXT_TAIL]],
  		   ".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
  			rdp->nxttail[RCU_NEXT_READY_TAIL]],
  		   ".W"[rdp->nxttail[RCU_DONE_TAIL] !=
  			rdp->nxttail[RCU_WAIT_TAIL]],

  		   ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]);
  #ifdef CONFIG_RCU_BOOST
  	seq_printf(m, " kt=%d/%c/%d ktl=%x",

  		   per_cpu(rcu_cpu_has_work, rdp->cpu),
  		   convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
  					  rdp->cpu)),

  		   per_cpu(rcu_cpu_kthread_cpu, rdp->cpu),

  		   per_cpu(rcu_cpu_kthread_loops, rdp->cpu) & 0xffff);
  #endif /* #ifdef CONFIG_RCU_BOOST */
  	seq_printf(m, " b=%ld", rdp->blimit);

  	seq_printf(m, " ci=%lu co=%lu ca=%lu
  ",
  		   rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);

  }
  
  #define PRINT_RCU_DATA(name, func, m) \
  	do { \
  		int _p_r_d_i; \
  		\
  		for_each_possible_cpu(_p_r_d_i) \
  			func(m, &per_cpu(name, _p_r_d_i)); \
  	} while (0)
  
  static int show_rcudata(struct seq_file *m, void *unused)
  {

  #ifdef CONFIG_TREE_PREEMPT_RCU
  	seq_puts(m, "rcu_preempt:
  ");
  	PRINT_RCU_DATA(rcu_preempt_data, print_one_rcu_data, m);
  #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */

  	seq_puts(m, "rcu_sched:
  ");
  	PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data, m);

  	seq_puts(m, "rcu_bh:
  ");
  	PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data, m);
  	return 0;
  }
  
  static int rcudata_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, show_rcudata, NULL);
  }

  static const struct file_operations rcudata_fops = {

  	.owner = THIS_MODULE,
  	.open = rcudata_open,
  	.read = seq_read,
  	.llseek = seq_lseek,
  	.release = single_release,
  };
  
  static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
  {
  	if (!rdp->beenonline)
  		return;

  	seq_printf(m, "%d,%s,%lu,%lu,%d,%lu,%d",

  		   rdp->cpu,

  		   cpu_is_offline(rdp->cpu) ? "\"N\"" : "\"Y\"",

  		   rdp->completed, rdp->gpnum,
  		   rdp->passed_quiesc, rdp->passed_quiesc_completed,

  		   rdp->qs_pending);

  #ifdef CONFIG_NO_HZ
  	seq_printf(m, ",%d,%d,%d,%lu",

  		   atomic_read(&rdp->dynticks->dynticks),

  		   rdp->dynticks->dynticks_nesting,

  		   rdp->dynticks->dynticks_nmi_nesting,

  		   rdp->dynticks_fqs);
  #endif /* #ifdef CONFIG_NO_HZ */
  	seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi);

  	seq_printf(m, ",%ld,\"%c%c%c%c\"", rdp->qlen,

  		   ".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
  			rdp->nxttail[RCU_NEXT_TAIL]],
  		   ".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
  			rdp->nxttail[RCU_NEXT_READY_TAIL]],
  		   ".W"[rdp->nxttail[RCU_DONE_TAIL] !=
  			rdp->nxttail[RCU_WAIT_TAIL]],

  		   ".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]);
  #ifdef CONFIG_RCU_BOOST
  	seq_printf(m, ",%d,\"%c\"",

  		   per_cpu(rcu_cpu_has_work, rdp->cpu),
  		   convert_kthread_status(per_cpu(rcu_cpu_kthread_status,

  					  rdp->cpu)));
  #endif /* #ifdef CONFIG_RCU_BOOST */
  	seq_printf(m, ",%ld", rdp->blimit);

  	seq_printf(m, ",%lu,%lu,%lu
  ",
  		   rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);

  }
  
  static int show_rcudata_csv(struct seq_file *m, void *unused)
  {

  	seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pqc\",\"pq\",");

  #ifdef CONFIG_NO_HZ

  	seq_puts(m, "\"dt\",\"dt nesting\",\"dt NMI nesting\",\"df\",");

  #endif /* #ifdef CONFIG_NO_HZ */

  	seq_puts(m, "\"of\",\"ri\",\"ql\",\"qs\"");
  #ifdef CONFIG_RCU_BOOST
  	seq_puts(m, "\"kt\",\"ktl\"");
  #endif /* #ifdef CONFIG_RCU_BOOST */
  	seq_puts(m, ",\"b\",\"ci\",\"co\",\"ca\"
  ");

  #ifdef CONFIG_TREE_PREEMPT_RCU
  	seq_puts(m, "\"rcu_preempt:\"
  ");
  	PRINT_RCU_DATA(rcu_preempt_data, print_one_rcu_data_csv, m);
  #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */

  	seq_puts(m, "\"rcu_sched:\"
  ");
  	PRINT_RCU_DATA(rcu_sched_data, print_one_rcu_data_csv, m);

  	seq_puts(m, "\"rcu_bh:\"
  ");
  	PRINT_RCU_DATA(rcu_bh_data, print_one_rcu_data_csv, m);
  	return 0;
  }
  
  static int rcudata_csv_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, show_rcudata_csv, NULL);
  }

  static const struct file_operations rcudata_csv_fops = {

  	.owner = THIS_MODULE,
  	.open = rcudata_csv_open,
  	.read = seq_read,
  	.llseek = seq_lseek,
  	.release = single_release,
  };

  #ifdef CONFIG_RCU_BOOST
  
  static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp)
  {

  	seq_printf(m,  "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu "

  		   "j=%04x bt=%04x
  ",
  		   rnp->grplo, rnp->grphi,
  		   "T."[list_empty(&rnp->blkd_tasks)],
  		   "N."[!rnp->gp_tasks],
  		   "E."[!rnp->exp_tasks],
  		   "B."[!rnp->boost_tasks],

  		   convert_kthread_status(rnp->boost_kthread_status),

  		   rnp->n_tasks_boosted, rnp->n_exp_boosts,
  		   rnp->n_normal_boosts,
  		   (int)(jiffies & 0xffff),
  		   (int)(rnp->boost_time & 0xffff));
  	seq_printf(m, "%s: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu
  ",
  		   "     balk",
  		   rnp->n_balk_blkd_tasks,
  		   rnp->n_balk_exp_gp_tasks,
  		   rnp->n_balk_boost_tasks,
  		   rnp->n_balk_notblocked,
  		   rnp->n_balk_notyet,
  		   rnp->n_balk_nos);
  }
  
  static int show_rcu_node_boost(struct seq_file *m, void *unused)
  {
  	struct rcu_node *rnp;
  
  	rcu_for_each_leaf_node(&rcu_preempt_state, rnp)
  		print_one_rcu_node_boost(m, rnp);
  	return 0;
  }
  
  static int rcu_node_boost_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, show_rcu_node_boost, NULL);
  }
  
  static const struct file_operations rcu_node_boost_fops = {
  	.owner = THIS_MODULE,
  	.open = rcu_node_boost_open,
  	.read = seq_read,
  	.llseek = seq_lseek,
  	.release = single_release,
  };
  
  /*
   * Create the rcuboost debugfs entry.  Standard error return.
   */
  static int rcu_boost_trace_create_file(struct dentry *rcudir)
  {
  	return !debugfs_create_file("rcuboost", 0444, rcudir, NULL,
  				    &rcu_node_boost_fops);
  }
  
  #else /* #ifdef CONFIG_RCU_BOOST */
  
  static int rcu_boost_trace_create_file(struct dentry *rcudir)
  {
  	return 0;  /* There cannot be an error if we didn't create it! */
  }
  
  #endif /* #else #ifdef CONFIG_RCU_BOOST */

  static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
  {

  	unsigned long gpnum;

  	int level = 0;
  	struct rcu_node *rnp;

  	gpnum = rsp->gpnum;

  	seq_printf(m, "c=%lu g=%lu s=%d jfq=%ld j=%x "

  		      "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu
  ",

  		   rsp->completed, gpnum, rsp->signaled,

  		   (long)(rsp->jiffies_force_qs - jiffies),
  		   (int)(jiffies & 0xffff),
  		   rsp->n_force_qs, rsp->n_force_qs_ngp,
  		   rsp->n_force_qs - rsp->n_force_qs_ngp,

  		   rsp->n_force_qs_lh);

  	for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < NUM_RCU_NODES; rnp++) {
  		if (rnp->level != level) {
  			seq_puts(m, "
  ");
  			level = rnp->level;
  		}

  		seq_printf(m, "%lx/%lx %c%c>%c %d:%d ^%d    ",

  			   rnp->qsmask, rnp->qsmaskinit,

  			   ".G"[rnp->gp_tasks != NULL],
  			   ".E"[rnp->exp_tasks != NULL],
  			   ".T"[!list_empty(&rnp->blkd_tasks)],

  			   rnp->grplo, rnp->grphi, rnp->grpnum);
  	}
  	seq_puts(m, "
  ");
  }
  
  static int show_rcuhier(struct seq_file *m, void *unused)
  {

  #ifdef CONFIG_TREE_PREEMPT_RCU
  	seq_puts(m, "rcu_preempt:
  ");
  	print_one_rcu_state(m, &rcu_preempt_state);
  #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */

  	seq_puts(m, "rcu_sched:
  ");
  	print_one_rcu_state(m, &rcu_sched_state);

  	seq_puts(m, "rcu_bh:
  ");
  	print_one_rcu_state(m, &rcu_bh_state);
  	return 0;
  }
  
  static int rcuhier_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, show_rcuhier, NULL);
  }

  static const struct file_operations rcuhier_fops = {

  	.owner = THIS_MODULE,
  	.open = rcuhier_open,
  	.read = seq_read,
  	.llseek = seq_lseek,
  	.release = single_release,
  };

  static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp)
  {
  	unsigned long flags;
  	unsigned long completed;
  	unsigned long gpnum;
  	unsigned long gpage;
  	unsigned long gpmax;
  	struct rcu_node *rnp = &rsp->node[0];
  
  	raw_spin_lock_irqsave(&rnp->lock, flags);
  	completed = rsp->completed;
  	gpnum = rsp->gpnum;
  	if (rsp->completed == rsp->gpnum)
  		gpage = 0;
  	else
  		gpage = jiffies - rsp->gp_start;
  	gpmax = rsp->gp_max;
  	raw_spin_unlock_irqrestore(&rnp->lock, flags);
  	seq_printf(m, "%s: completed=%ld  gpnum=%lu  age=%ld  max=%ld
  ",
  		   rsp->name, completed, gpnum, gpage, gpmax);
  }

  static int show_rcugp(struct seq_file *m, void *unused)
  {

  #ifdef CONFIG_TREE_PREEMPT_RCU

  	show_one_rcugp(m, &rcu_preempt_state);

  #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */

  	show_one_rcugp(m, &rcu_sched_state);
  	show_one_rcugp(m, &rcu_bh_state);

  	return 0;
  }
  
  static int rcugp_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, show_rcugp, NULL);
  }

  static const struct file_operations rcugp_fops = {

  	.owner = THIS_MODULE,
  	.open = rcugp_open,
  	.read = seq_read,
  	.llseek = seq_lseek,
  	.release = single_release,
  };

  static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
  {
  	seq_printf(m, "%3d%cnp=%ld "

  		   "qsp=%ld rpq=%ld cbr=%ld cng=%ld "
  		   "gpc=%ld gps=%ld nf=%ld nn=%ld
  ",

  		   rdp->cpu,
  		   cpu_is_offline(rdp->cpu) ? '!' : ' ',
  		   rdp->n_rcu_pending,
  		   rdp->n_rp_qs_pending,

  		   rdp->n_rp_report_qs,

  		   rdp->n_rp_cb_ready,
  		   rdp->n_rp_cpu_needs_gp,
  		   rdp->n_rp_gp_completed,
  		   rdp->n_rp_gp_started,
  		   rdp->n_rp_need_fqs,
  		   rdp->n_rp_need_nothing);
  }
  
  static void print_rcu_pendings(struct seq_file *m, struct rcu_state *rsp)
  {
  	int cpu;
  	struct rcu_data *rdp;
  
  	for_each_possible_cpu(cpu) {

  		rdp = per_cpu_ptr(rsp->rda, cpu);

  		if (rdp->beenonline)
  			print_one_rcu_pending(m, rdp);
  	}
  }
  
  static int show_rcu_pending(struct seq_file *m, void *unused)
  {

  #ifdef CONFIG_TREE_PREEMPT_RCU
  	seq_puts(m, "rcu_preempt:
  ");
  	print_rcu_pendings(m, &rcu_preempt_state);
  #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */

  	seq_puts(m, "rcu_sched:
  ");
  	print_rcu_pendings(m, &rcu_sched_state);

  	seq_puts(m, "rcu_bh:
  ");
  	print_rcu_pendings(m, &rcu_bh_state);
  	return 0;
  }
  
  static int rcu_pending_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, show_rcu_pending, NULL);
  }

  static const struct file_operations rcu_pending_fops = {

  	.owner = THIS_MODULE,
  	.open = rcu_pending_open,
  	.read = seq_read,
  	.llseek = seq_lseek,
  	.release = single_release,
  };

  static int show_rcutorture(struct seq_file *m, void *unused)
  {
  	seq_printf(m, "rcutorture test sequence: %lu %s
  ",
  		   rcutorture_testseq >> 1,
  		   (rcutorture_testseq & 0x1) ? "(test in progress)" : "");
  	seq_printf(m, "rcutorture update version number: %lu
  ",
  		   rcutorture_vernum);
  	return 0;
  }
  
  static int rcutorture_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, show_rcutorture, NULL);
  }
  
  static const struct file_operations rcutorture_fops = {
  	.owner = THIS_MODULE,
  	.open = rcutorture_open,
  	.read = seq_read,
  	.llseek = seq_lseek,
  	.release = single_release,
  };

  static struct dentry *rcudir;

  static int __init rcutree_trace_init(void)

  {

  	struct dentry *retval;

  	rcudir = debugfs_create_dir("rcu", NULL);
  	if (!rcudir)

  		goto free_out;

  	retval = debugfs_create_file("rcudata", 0444, rcudir,

  						NULL, &rcudata_fops);

  	if (!retval)

  		goto free_out;

  	retval = debugfs_create_file("rcudata.csv", 0444, rcudir,

  						NULL, &rcudata_csv_fops);

  	if (!retval)

  		goto free_out;

  	if (rcu_boost_trace_create_file(rcudir))
  		goto free_out;

  	retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
  	if (!retval)

  		goto free_out;

  	retval = debugfs_create_file("rcuhier", 0444, rcudir,

  						NULL, &rcuhier_fops);

  	if (!retval)

  		goto free_out;

  	retval = debugfs_create_file("rcu_pending", 0444, rcudir,

  						NULL, &rcu_pending_fops);

  	if (!retval)

  		goto free_out;

  
  	retval = debugfs_create_file("rcutorture", 0444, rcudir,
  						NULL, &rcutorture_fops);
  	if (!retval)
  		goto free_out;

  	return 0;
  free_out:

  	debugfs_remove_recursive(rcudir);

  	return 1;
  }

  static void __exit rcutree_trace_cleanup(void)

  {

  	debugfs_remove_recursive(rcudir);

  }

  module_init(rcutree_trace_init);
  module_exit(rcutree_trace_cleanup);

  
  MODULE_AUTHOR("Paul E. McKenney");
  MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
  MODULE_LICENSE("GPL");