1/*
   2 * Infrastructure for profiling code inserted by 'gcc -pg'.
   3 *
   4 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
   5 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
   6 *
   7 * Originally ported from the -rt patch by:
   8 *   Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
   9 *
  10 * Based on code in the latency_tracer, that is:
  11 *
  12 *  Copyright (C) 2004-2006 Ingo Molnar
  13 *  Copyright (C) 2004 William Lee Irwin III
  14 */
  15
  16#include <linux/stop_machine.h>
  17#include <linux/clocksource.h>
 
  18#include <linux/kallsyms.h>
 
  19#include <linux/seq_file.h>
  20#include <linux/suspend.h>
  21#include <linux/debugfs.h>
  22#include <linux/hardirq.h>
  23#include <linux/kthread.h>
  24#include <linux/uaccess.h>
 
 
  25#include <linux/ftrace.h>
  26#include <linux/sysctl.h>
  27#include <linux/slab.h>
  28#include <linux/ctype.h>
 
  29#include <linux/list.h>
  30#include <linux/hash.h>
  31#include <linux/rcupdate.h>
 
  32
  33#include <trace/events/sched.h>
  34
 
  35#include <asm/setup.h>
  36
 
  37#include "trace_output.h"
  38#include "trace_stat.h"
  39
  40#define FTRACE_WARN_ON(cond)			\
  41	({					\
  42		int ___r = cond;		\
  43		if (WARN_ON(___r))		\
  44			ftrace_kill();		\
  45		___r;				\
  46	})
  47
  48#define FTRACE_WARN_ON_ONCE(cond)		\
  49	({					\
  50		int ___r = cond;		\
  51		if (WARN_ON_ONCE(___r))		\
  52			ftrace_kill();		\
  53		___r;				\
  54	})
  55
  56/* hash bits for specific function selection */
  57#define FTRACE_HASH_BITS 7
  58#define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
  59#define FTRACE_HASH_DEFAULT_BITS 10
  60#define FTRACE_HASH_MAX_BITS 12
  61
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  62/* ftrace_enabled is a method to turn ftrace on or off */
  63int ftrace_enabled __read_mostly;
  64static int last_ftrace_enabled;
  65
  66/* Quick disabling of function tracer. */
  67int function_trace_stop;
 
 
  68
  69/* List for set_ftrace_pid's pids. */
  70LIST_HEAD(ftrace_pids);
  71struct ftrace_pid {
  72	struct list_head list;
  73	struct pid *pid;
  74};
 
 
 
 
 
 
 
  75
  76/*
  77 * ftrace_disabled is set when an anomaly is discovered.
  78 * ftrace_disabled is much stronger than ftrace_enabled.
  79 */
  80static int ftrace_disabled __read_mostly;
  81
  82static DEFINE_MUTEX(ftrace_lock);
  83
  84static struct ftrace_ops ftrace_list_end __read_mostly = {
  85	.func		= ftrace_stub,
  86};
  87
  88static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
  89static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
  90ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
  91static ftrace_func_t __ftrace_trace_function_delay __read_mostly = ftrace_stub;
  92ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
  93ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
  94static struct ftrace_ops global_ops;
  95
  96static void
  97ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
 
 
 
 
 
 
  98
  99/*
 100 * Traverse the ftrace_global_list, invoking all entries.  The reason that we
 101 * can use rcu_dereference_raw() is that elements removed from this list
 102 * are simply leaked, so there is no need to interact with a grace-period
 103 * mechanism.  The rcu_dereference_raw() calls are needed to handle
 104 * concurrent insertions into the ftrace_global_list.
 105 *
 106 * Silly Alpha and silly pointer-speculation compiler optimizations!
 107 */
 108static void ftrace_global_list_func(unsigned long ip,
 109				    unsigned long parent_ip)
 110{
 111	struct ftrace_ops *op;
 112
 113	if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT)))
 114		return;
 115
 116	trace_recursion_set(TRACE_GLOBAL_BIT);
 117	op = rcu_dereference_raw(ftrace_global_list); /*see above*/
 118	while (op != &ftrace_list_end) {
 119		op->func(ip, parent_ip);
 120		op = rcu_dereference_raw(op->next); /*see above*/
 121	};
 122	trace_recursion_clear(TRACE_GLOBAL_BIT);
 123}
 124
 125static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
 
 126{
 127	if (!test_tsk_trace_trace(current))
 128		return;
 129
 130	ftrace_pid_function(ip, parent_ip);
 131}
 
 
 
 
 
 
 132
 133static void set_ftrace_pid_function(ftrace_func_t func)
 134{
 135	/* do not set ftrace_pid_function to itself! */
 136	if (func != ftrace_pid_func)
 137		ftrace_pid_function = func;
 138}
 139
 140/**
 141 * clear_ftrace_function - reset the ftrace function
 142 *
 143 * This NULLs the ftrace function and in essence stops
 144 * tracing.  There may be lag
 145 */
 146void clear_ftrace_function(void)
 147{
 148	ftrace_trace_function = ftrace_stub;
 149	__ftrace_trace_function = ftrace_stub;
 150	__ftrace_trace_function_delay = ftrace_stub;
 151	ftrace_pid_function = ftrace_stub;
 152}
 153
 154#undef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 155#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 156/*
 157 * For those archs that do not test ftrace_trace_stop in their
 158 * mcount call site, we need to do it from C.
 159 */
 160static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
 161{
 162	if (function_trace_stop)
 163		return;
 
 
 
 
 
 164
 165	__ftrace_trace_function(ip, parent_ip);
 166}
 167#endif
 168
 169static void update_global_ops(void)
 170{
 171	ftrace_func_t func;
 172
 173	/*
 174	 * If there's only one function registered, then call that
 175	 * function directly. Otherwise, we need to iterate over the
 176	 * registered callers.
 177	 */
 178	if (ftrace_global_list == &ftrace_list_end ||
 179	    ftrace_global_list->next == &ftrace_list_end)
 180		func = ftrace_global_list->func;
 181	else
 182		func = ftrace_global_list_func;
 183
 184	/* If we filter on pids, update to use the pid function */
 185	if (!list_empty(&ftrace_pids)) {
 186		set_ftrace_pid_function(func);
 187		func = ftrace_pid_func;
 
 
 
 
 
 
 
 
 
 
 
 
 
 188	}
 189
 190	global_ops.func = func;
 191}
 192
 193static void update_ftrace_function(void)
 194{
 195	ftrace_func_t func;
 196
 197	update_global_ops();
 
 
 
 
 
 
 
 
 
 
 
 198
 
 199	/*
 200	 * If we are at the end of the list and this ops is
 201	 * not dynamic, then have the mcount trampoline call
 202	 * the function directly
 
 
 
 
 
 203	 */
 204	if (ftrace_ops_list == &ftrace_list_end ||
 205	    (ftrace_ops_list->next == &ftrace_list_end &&
 206	     !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC)))
 207		func = ftrace_ops_list->func;
 208	else
 209		func = ftrace_ops_list_func;
 
 
 
 
 
 
 
 
 210
 211#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 212	ftrace_trace_function = func;
 213#else
 214#ifdef CONFIG_DYNAMIC_FTRACE
 215	/* do not update till all functions have been modified */
 216	__ftrace_trace_function_delay = func;
 217#else
 218	__ftrace_trace_function = func;
 219#endif
 220	ftrace_trace_function = ftrace_test_stop_func;
 221#endif
 222}
 223
 224static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
 
 225{
 226	ops->next = *list;
 
 227	/*
 228	 * We are entering ops into the list but another
 229	 * CPU might be walking that list. We need to make sure
 230	 * the ops->next pointer is valid before another CPU sees
 231	 * the ops pointer included into the list.
 232	 */
 233	rcu_assign_pointer(*list, ops);
 234}
 235
 236static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
 
 237{
 238	struct ftrace_ops **p;
 239
 240	/*
 241	 * If we are removing the last function, then simply point
 242	 * to the ftrace_stub.
 243	 */
 244	if (*list == ops && ops->next == &ftrace_list_end) {
 
 
 
 245		*list = &ftrace_list_end;
 246		return 0;
 247	}
 248
 249	for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
 250		if (*p == ops)
 251			break;
 252
 253	if (*p != ops)
 254		return -1;
 255
 256	*p = (*p)->next;
 257	return 0;
 258}
 259
 260static int __register_ftrace_function(struct ftrace_ops *ops)
 261{
 262	if (ftrace_disabled)
 263		return -ENODEV;
 264
 265	if (FTRACE_WARN_ON(ops == &global_ops))
 
 
 266		return -EINVAL;
 267
 268	if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
 269		return -EBUSY;
 270
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 271	if (!core_kernel_data((unsigned long)ops))
 272		ops->flags |= FTRACE_OPS_FL_DYNAMIC;
 273
 274	if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
 275		int first = ftrace_global_list == &ftrace_list_end;
 276		add_ftrace_ops(&ftrace_global_list, ops);
 277		ops->flags |= FTRACE_OPS_FL_ENABLED;
 278		if (first)
 279			add_ftrace_ops(&ftrace_ops_list, &global_ops);
 280	} else
 281		add_ftrace_ops(&ftrace_ops_list, ops);
 
 282
 283	if (ftrace_enabled)
 284		update_ftrace_function();
 285
 286	return 0;
 287}
 288
 289static int __unregister_ftrace_function(struct ftrace_ops *ops)
 290{
 291	int ret;
 292
 293	if (ftrace_disabled)
 294		return -ENODEV;
 295
 296	if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
 297		return -EBUSY;
 298
 299	if (FTRACE_WARN_ON(ops == &global_ops))
 300		return -EINVAL;
 301
 302	if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
 303		ret = remove_ftrace_ops(&ftrace_global_list, ops);
 304		if (!ret && ftrace_global_list == &ftrace_list_end)
 305			ret = remove_ftrace_ops(&ftrace_ops_list, &global_ops);
 306		if (!ret)
 307			ops->flags &= ~FTRACE_OPS_FL_ENABLED;
 308	} else
 309		ret = remove_ftrace_ops(&ftrace_ops_list, ops);
 310
 311	if (ret < 0)
 312		return ret;
 313
 314	if (ftrace_enabled)
 315		update_ftrace_function();
 316
 317	/*
 318	 * Dynamic ops may be freed, we must make sure that all
 319	 * callers are done before leaving this function.
 320	 */
 321	if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
 322		synchronize_sched();
 323
 324	return 0;
 325}
 326
 327static void ftrace_update_pid_func(void)
 328{
 
 
 329	/* Only do something if we are tracing something */
 330	if (ftrace_trace_function == ftrace_stub)
 331		return;
 332
 
 
 
 
 
 
 
 
 333	update_ftrace_function();
 334}
 335
 336#ifdef CONFIG_FUNCTION_PROFILER
 337struct ftrace_profile {
 338	struct hlist_node		node;
 339	unsigned long			ip;
 340	unsigned long			counter;
 341#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 342	unsigned long long		time;
 343	unsigned long long		time_squared;
 344#endif
 345};
 346
 347struct ftrace_profile_page {
 348	struct ftrace_profile_page	*next;
 349	unsigned long			index;
 350	struct ftrace_profile		records[];
 351};
 352
 353struct ftrace_profile_stat {
 354	atomic_t			disabled;
 355	struct hlist_head		*hash;
 356	struct ftrace_profile_page	*pages;
 357	struct ftrace_profile_page	*start;
 358	struct tracer_stat		stat;
 359};
 360
 361#define PROFILE_RECORDS_SIZE						\
 362	(PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
 363
 364#define PROFILES_PER_PAGE					\
 365	(PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
 366
 367static int ftrace_profile_bits __read_mostly;
 368static int ftrace_profile_enabled __read_mostly;
 369
 370/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
 371static DEFINE_MUTEX(ftrace_profile_lock);
 372
 373static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
 374
 375#define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
 
 376
 377static void *
 378function_stat_next(void *v, int idx)
 379{
 380	struct ftrace_profile *rec = v;
 381	struct ftrace_profile_page *pg;
 382
 383	pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
 384
 385 again:
 386	if (idx != 0)
 387		rec++;
 388
 389	if ((void *)rec >= (void *)&pg->records[pg->index]) {
 390		pg = pg->next;
 391		if (!pg)
 392			return NULL;
 393		rec = &pg->records[0];
 394		if (!rec->counter)
 395			goto again;
 396	}
 397
 398	return rec;
 399}
 400
 401static void *function_stat_start(struct tracer_stat *trace)
 402{
 403	struct ftrace_profile_stat *stat =
 404		container_of(trace, struct ftrace_profile_stat, stat);
 405
 406	if (!stat || !stat->start)
 407		return NULL;
 408
 409	return function_stat_next(&stat->start->records[0], 0);
 410}
 411
 412#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 413/* function graph compares on total time */
 414static int function_stat_cmp(void *p1, void *p2)
 415{
 416	struct ftrace_profile *a = p1;
 417	struct ftrace_profile *b = p2;
 418
 419	if (a->time < b->time)
 420		return -1;
 421	if (a->time > b->time)
 422		return 1;
 423	else
 424		return 0;
 425}
 426#else
 427/* not function graph compares against hits */
 428static int function_stat_cmp(void *p1, void *p2)
 429{
 430	struct ftrace_profile *a = p1;
 431	struct ftrace_profile *b = p2;
 432
 433	if (a->counter < b->counter)
 434		return -1;
 435	if (a->counter > b->counter)
 436		return 1;
 437	else
 438		return 0;
 439}
 440#endif
 441
 442static int function_stat_headers(struct seq_file *m)
 443{
 444#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 445	seq_printf(m, "  Function                               "
 446		   "Hit    Time            Avg             s^2\n"
 447		      "  --------                               "
 448		   "---    ----            ---             ---\n");
 449#else
 450	seq_printf(m, "  Function                               Hit\n"
 451		      "  --------                               ---\n");
 452#endif
 453	return 0;
 454}
 455
 456static int function_stat_show(struct seq_file *m, void *v)
 457{
 458	struct ftrace_profile *rec = v;
 459	char str[KSYM_SYMBOL_LEN];
 460	int ret = 0;
 461#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 462	static struct trace_seq s;
 463	unsigned long long avg;
 464	unsigned long long stddev;
 465#endif
 466	mutex_lock(&ftrace_profile_lock);
 467
 468	/* we raced with function_profile_reset() */
 469	if (unlikely(rec->counter == 0)) {
 470		ret = -EBUSY;
 471		goto out;
 472	}
 473
 
 
 
 
 
 
 474	kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 475	seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
 476
 477#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 478	seq_printf(m, "    ");
 479	avg = rec->time;
 480	do_div(avg, rec->counter);
 481
 482	/* Sample standard deviation (s^2) */
 483	if (rec->counter <= 1)
 484		stddev = 0;
 485	else {
 486		stddev = rec->time_squared - rec->counter * avg * avg;
 
 
 
 
 
 
 487		/*
 488		 * Divide only 1000 for ns^2 -> us^2 conversion.
 489		 * trace_print_graph_duration will divide 1000 again.
 490		 */
 491		do_div(stddev, (rec->counter - 1) * 1000);
 
 492	}
 493
 494	trace_seq_init(&s);
 495	trace_print_graph_duration(rec->time, &s);
 496	trace_seq_puts(&s, "    ");
 497	trace_print_graph_duration(avg, &s);
 498	trace_seq_puts(&s, "    ");
 499	trace_print_graph_duration(stddev, &s);
 500	trace_print_seq(m, &s);
 501#endif
 502	seq_putc(m, '\n');
 503out:
 504	mutex_unlock(&ftrace_profile_lock);
 505
 506	return ret;
 507}
 508
 509static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
 510{
 511	struct ftrace_profile_page *pg;
 512
 513	pg = stat->pages = stat->start;
 514
 515	while (pg) {
 516		memset(pg->records, 0, PROFILE_RECORDS_SIZE);
 517		pg->index = 0;
 518		pg = pg->next;
 519	}
 520
 521	memset(stat->hash, 0,
 522	       FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
 523}
 524
 525int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
 526{
 527	struct ftrace_profile_page *pg;
 528	int functions;
 529	int pages;
 530	int i;
 531
 532	/* If we already allocated, do nothing */
 533	if (stat->pages)
 534		return 0;
 535
 536	stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
 537	if (!stat->pages)
 538		return -ENOMEM;
 539
 540#ifdef CONFIG_DYNAMIC_FTRACE
 541	functions = ftrace_update_tot_cnt;
 542#else
 543	/*
 544	 * We do not know the number of functions that exist because
 545	 * dynamic tracing is what counts them. With past experience
 546	 * we have around 20K functions. That should be more than enough.
 547	 * It is highly unlikely we will execute every function in
 548	 * the kernel.
 549	 */
 550	functions = 20000;
 551#endif
 552
 553	pg = stat->start = stat->pages;
 554
 555	pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
 556
 557	for (i = 0; i < pages; i++) {
 558		pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 559		if (!pg->next)
 560			goto out_free;
 561		pg = pg->next;
 562	}
 563
 564	return 0;
 565
 566 out_free:
 567	pg = stat->start;
 568	while (pg) {
 569		unsigned long tmp = (unsigned long)pg;
 570
 571		pg = pg->next;
 572		free_page(tmp);
 573	}
 574
 575	free_page((unsigned long)stat->pages);
 576	stat->pages = NULL;
 577	stat->start = NULL;
 578
 579	return -ENOMEM;
 580}
 581
 582static int ftrace_profile_init_cpu(int cpu)
 583{
 584	struct ftrace_profile_stat *stat;
 585	int size;
 586
 587	stat = &per_cpu(ftrace_profile_stats, cpu);
 588
 589	if (stat->hash) {
 590		/* If the profile is already created, simply reset it */
 591		ftrace_profile_reset(stat);
 592		return 0;
 593	}
 594
 595	/*
 596	 * We are profiling all functions, but usually only a few thousand
 597	 * functions are hit. We'll make a hash of 1024 items.
 598	 */
 599	size = FTRACE_PROFILE_HASH_SIZE;
 600
 601	stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
 602
 603	if (!stat->hash)
 604		return -ENOMEM;
 605
 606	if (!ftrace_profile_bits) {
 607		size--;
 608
 609		for (; size; size >>= 1)
 610			ftrace_profile_bits++;
 611	}
 612
 613	/* Preallocate the function profiling pages */
 614	if (ftrace_profile_pages_init(stat) < 0) {
 615		kfree(stat->hash);
 616		stat->hash = NULL;
 617		return -ENOMEM;
 618	}
 619
 620	return 0;
 621}
 622
 623static int ftrace_profile_init(void)
 624{
 625	int cpu;
 626	int ret = 0;
 627
 628	for_each_online_cpu(cpu) {
 629		ret = ftrace_profile_init_cpu(cpu);
 630		if (ret)
 631			break;
 632	}
 633
 634	return ret;
 635}
 636
 637/* interrupts must be disabled */
 638static struct ftrace_profile *
 639ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
 640{
 641	struct ftrace_profile *rec;
 642	struct hlist_head *hhd;
 643	struct hlist_node *n;
 644	unsigned long key;
 645
 646	key = hash_long(ip, ftrace_profile_bits);
 647	hhd = &stat->hash[key];
 648
 649	if (hlist_empty(hhd))
 650		return NULL;
 651
 652	hlist_for_each_entry_rcu(rec, n, hhd, node) {
 653		if (rec->ip == ip)
 654			return rec;
 655	}
 656
 657	return NULL;
 658}
 659
 660static void ftrace_add_profile(struct ftrace_profile_stat *stat,
 661			       struct ftrace_profile *rec)
 662{
 663	unsigned long key;
 664
 665	key = hash_long(rec->ip, ftrace_profile_bits);
 666	hlist_add_head_rcu(&rec->node, &stat->hash[key]);
 667}
 668
 669/*
 670 * The memory is already allocated, this simply finds a new record to use.
 671 */
 672static struct ftrace_profile *
 673ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
 674{
 675	struct ftrace_profile *rec = NULL;
 676
 677	/* prevent recursion (from NMIs) */
 678	if (atomic_inc_return(&stat->disabled) != 1)
 679		goto out;
 680
 681	/*
 682	 * Try to find the function again since an NMI
 683	 * could have added it
 684	 */
 685	rec = ftrace_find_profiled_func(stat, ip);
 686	if (rec)
 687		goto out;
 688
 689	if (stat->pages->index == PROFILES_PER_PAGE) {
 690		if (!stat->pages->next)
 691			goto out;
 692		stat->pages = stat->pages->next;
 693	}
 694
 695	rec = &stat->pages->records[stat->pages->index++];
 696	rec->ip = ip;
 697	ftrace_add_profile(stat, rec);
 698
 699 out:
 700	atomic_dec(&stat->disabled);
 701
 702	return rec;
 703}
 704
 705static void
 706function_profile_call(unsigned long ip, unsigned long parent_ip)
 
 707{
 708	struct ftrace_profile_stat *stat;
 709	struct ftrace_profile *rec;
 710	unsigned long flags;
 711
 712	if (!ftrace_profile_enabled)
 713		return;
 714
 715	local_irq_save(flags);
 716
 717	stat = &__get_cpu_var(ftrace_profile_stats);
 718	if (!stat->hash || !ftrace_profile_enabled)
 719		goto out;
 720
 721	rec = ftrace_find_profiled_func(stat, ip);
 722	if (!rec) {
 723		rec = ftrace_profile_alloc(stat, ip);
 724		if (!rec)
 725			goto out;
 726	}
 727
 728	rec->counter++;
 729 out:
 730	local_irq_restore(flags);
 731}
 732
 733#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 
 
 
 
 
 
 
 734static int profile_graph_entry(struct ftrace_graph_ent *trace)
 735{
 736	function_profile_call(trace->func, 0);
 
 
 
 
 
 
 
 
 
 
 
 737	return 1;
 738}
 739
 740static void profile_graph_return(struct ftrace_graph_ret *trace)
 741{
 
 742	struct ftrace_profile_stat *stat;
 743	unsigned long long calltime;
 744	struct ftrace_profile *rec;
 745	unsigned long flags;
 746
 747	local_irq_save(flags);
 748	stat = &__get_cpu_var(ftrace_profile_stats);
 749	if (!stat->hash || !ftrace_profile_enabled)
 750		goto out;
 751
 752	/* If the calltime was zero'd ignore it */
 753	if (!trace->calltime)
 754		goto out;
 755
 756	calltime = trace->rettime - trace->calltime;
 757
 758	if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
 759		int index;
 760
 761		index = trace->depth;
 762
 763		/* Append this call time to the parent time to subtract */
 764		if (index)
 765			current->ret_stack[index - 1].subtime += calltime;
 766
 767		if (current->ret_stack[index].subtime < calltime)
 768			calltime -= current->ret_stack[index].subtime;
 
 
 769		else
 770			calltime = 0;
 771	}
 772
 773	rec = ftrace_find_profiled_func(stat, trace->func);
 774	if (rec) {
 775		rec->time += calltime;
 776		rec->time_squared += calltime * calltime;
 777	}
 778
 779 out:
 780	local_irq_restore(flags);
 781}
 782
 
 
 
 
 
 783static int register_ftrace_profiler(void)
 784{
 785	return register_ftrace_graph(&profile_graph_return,
 786				     &profile_graph_entry);
 787}
 788
 789static void unregister_ftrace_profiler(void)
 790{
 791	unregister_ftrace_graph();
 792}
 793#else
 794static struct ftrace_ops ftrace_profile_ops __read_mostly = {
 795	.func		= function_profile_call,
 
 
 796};
 797
 798static int register_ftrace_profiler(void)
 799{
 800	return register_ftrace_function(&ftrace_profile_ops);
 801}
 802
 803static void unregister_ftrace_profiler(void)
 804{
 805	unregister_ftrace_function(&ftrace_profile_ops);
 806}
 807#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 808
 809static ssize_t
 810ftrace_profile_write(struct file *filp, const char __user *ubuf,
 811		     size_t cnt, loff_t *ppos)
 812{
 813	unsigned long val;
 814	int ret;
 815
 816	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
 817	if (ret)
 818		return ret;
 819
 820	val = !!val;
 821
 822	mutex_lock(&ftrace_profile_lock);
 823	if (ftrace_profile_enabled ^ val) {
 824		if (val) {
 825			ret = ftrace_profile_init();
 826			if (ret < 0) {
 827				cnt = ret;
 828				goto out;
 829			}
 830
 831			ret = register_ftrace_profiler();
 832			if (ret < 0) {
 833				cnt = ret;
 834				goto out;
 835			}
 836			ftrace_profile_enabled = 1;
 837		} else {
 838			ftrace_profile_enabled = 0;
 839			/*
 840			 * unregister_ftrace_profiler calls stop_machine
 841			 * so this acts like an synchronize_sched.
 842			 */
 843			unregister_ftrace_profiler();
 844		}
 845	}
 846 out:
 847	mutex_unlock(&ftrace_profile_lock);
 848
 849	*ppos += cnt;
 850
 851	return cnt;
 852}
 853
 854static ssize_t
 855ftrace_profile_read(struct file *filp, char __user *ubuf,
 856		     size_t cnt, loff_t *ppos)
 857{
 858	char buf[64];		/* big enough to hold a number */
 859	int r;
 860
 861	r = sprintf(buf, "%u\n", ftrace_profile_enabled);
 862	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 863}
 864
 865static const struct file_operations ftrace_profile_fops = {
 866	.open		= tracing_open_generic,
 867	.read		= ftrace_profile_read,
 868	.write		= ftrace_profile_write,
 869	.llseek		= default_llseek,
 870};
 871
 872/* used to initialize the real stat files */
 873static struct tracer_stat function_stats __initdata = {
 874	.name		= "functions",
 875	.stat_start	= function_stat_start,
 876	.stat_next	= function_stat_next,
 877	.stat_cmp	= function_stat_cmp,
 878	.stat_headers	= function_stat_headers,
 879	.stat_show	= function_stat_show
 880};
 881
 882static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
 883{
 884	struct ftrace_profile_stat *stat;
 885	struct dentry *entry;
 886	char *name;
 887	int ret;
 888	int cpu;
 889
 890	for_each_possible_cpu(cpu) {
 891		stat = &per_cpu(ftrace_profile_stats, cpu);
 892
 893		/* allocate enough for function name + cpu number */
 894		name = kmalloc(32, GFP_KERNEL);
 895		if (!name) {
 896			/*
 897			 * The files created are permanent, if something happens
 898			 * we still do not free memory.
 899			 */
 900			WARN(1,
 901			     "Could not allocate stat file for cpu %d\n",
 902			     cpu);
 903			return;
 904		}
 905		stat->stat = function_stats;
 906		snprintf(name, 32, "function%d", cpu);
 907		stat->stat.name = name;
 908		ret = register_stat_tracer(&stat->stat);
 909		if (ret) {
 910			WARN(1,
 911			     "Could not register function stat for cpu %d\n",
 912			     cpu);
 913			kfree(name);
 914			return;
 915		}
 916	}
 917
 918	entry = debugfs_create_file("function_profile_enabled", 0644,
 919				    d_tracer, NULL, &ftrace_profile_fops);
 920	if (!entry)
 921		pr_warning("Could not create debugfs "
 922			   "'function_profile_enabled' entry\n");
 923}
 924
 925#else /* CONFIG_FUNCTION_PROFILER */
 926static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
 927{
 928}
 929#endif /* CONFIG_FUNCTION_PROFILER */
 930
 931static struct pid * const ftrace_swapper_pid = &init_struct_pid;
 932
 933#ifdef CONFIG_DYNAMIC_FTRACE
 934
 
 
 
 
 
 
 
 
 935#ifndef CONFIG_FTRACE_MCOUNT_RECORD
 936# error Dynamic ftrace depends on MCOUNT_RECORD
 937#endif
 938
 939static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
 940
 941struct ftrace_func_probe {
 942	struct hlist_node	node;
 943	struct ftrace_probe_ops	*ops;
 944	unsigned long		flags;
 945	unsigned long		ip;
 946	void			*data;
 947	struct rcu_head		rcu;
 948};
 949
 950enum {
 951	FTRACE_ENABLE_CALLS		= (1 << 0),
 952	FTRACE_DISABLE_CALLS		= (1 << 1),
 953	FTRACE_UPDATE_TRACE_FUNC	= (1 << 2),
 954	FTRACE_START_FUNC_RET		= (1 << 3),
 955	FTRACE_STOP_FUNC_RET		= (1 << 4),
 956};
 957struct ftrace_func_entry {
 958	struct hlist_node hlist;
 959	unsigned long ip;
 960};
 961
 962struct ftrace_hash {
 963	unsigned long		size_bits;
 964	struct hlist_head	*buckets;
 965	unsigned long		count;
 966	struct rcu_head		rcu;
 967};
 968
 969/*
 970 * We make these constant because no one should touch them,
 971 * but they are used as the default "empty hash", to avoid allocating
 972 * it all the time. These are in a read only section such that if
 973 * anyone does try to modify it, it will cause an exception.
 974 */
 975static const struct hlist_head empty_buckets[1];
 976static const struct ftrace_hash empty_hash = {
 977	.buckets = (struct hlist_head *)empty_buckets,
 978};
 979#define EMPTY_HASH	((struct ftrace_hash *)&empty_hash)
 980
 981static struct ftrace_ops global_ops = {
 982	.func			= ftrace_stub,
 983	.notrace_hash		= EMPTY_HASH,
 984	.filter_hash		= EMPTY_HASH,
 
 
 
 
 985};
 986
 987static struct dyn_ftrace *ftrace_new_addrs;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 988
 989static DEFINE_MUTEX(ftrace_regex_lock);
 
 
 
 
 
 
 
 
 
 990
 991struct ftrace_page {
 992	struct ftrace_page	*next;
 
 993	int			index;
 994	struct dyn_ftrace	records[];
 995};
 996
 997#define ENTRIES_PER_PAGE \
 998  ((PAGE_SIZE - sizeof(struct ftrace_page)) / sizeof(struct dyn_ftrace))
 999
1000/* estimate from running different kernels */
1001#define NR_TO_INIT		10000
1002
1003static struct ftrace_page	*ftrace_pages_start;
1004static struct ftrace_page	*ftrace_pages;
1005
1006static struct dyn_ftrace *ftrace_free_records;
 
 
 
 
 
 
 
1007
1008static struct ftrace_func_entry *
1009ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
 
1010{
1011	unsigned long key;
1012	struct ftrace_func_entry *entry;
1013	struct hlist_head *hhd;
1014	struct hlist_node *n;
1015
1016	if (!hash->count)
1017		return NULL;
1018
1019	if (hash->size_bits > 0)
1020		key = hash_long(ip, hash->size_bits);
1021	else
1022		key = 0;
1023
 
1024	hhd = &hash->buckets[key];
1025
1026	hlist_for_each_entry_rcu(entry, n, hhd, hlist) {
1027		if (entry->ip == ip)
1028			return entry;
1029	}
1030	return NULL;
1031}
1032
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1033static void __add_hash_entry(struct ftrace_hash *hash,
1034			     struct ftrace_func_entry *entry)
1035{
1036	struct hlist_head *hhd;
1037	unsigned long key;
1038
1039	if (hash->size_bits)
1040		key = hash_long(entry->ip, hash->size_bits);
1041	else
1042		key = 0;
1043
1044	hhd = &hash->buckets[key];
1045	hlist_add_head(&entry->hlist, hhd);
1046	hash->count++;
1047}
1048
1049static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1050{
1051	struct ftrace_func_entry *entry;
1052
1053	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1054	if (!entry)
1055		return -ENOMEM;
1056
1057	entry->ip = ip;
1058	__add_hash_entry(hash, entry);
1059
1060	return 0;
1061}
1062
1063static void
1064free_hash_entry(struct ftrace_hash *hash,
1065		  struct ftrace_func_entry *entry)
1066{
1067	hlist_del(&entry->hlist);
1068	kfree(entry);
1069	hash->count--;
1070}
1071
1072static void
1073remove_hash_entry(struct ftrace_hash *hash,
1074		  struct ftrace_func_entry *entry)
1075{
1076	hlist_del(&entry->hlist);
1077	hash->count--;
1078}
1079
1080static void ftrace_hash_clear(struct ftrace_hash *hash)
1081{
1082	struct hlist_head *hhd;
1083	struct hlist_node *tp, *tn;
1084	struct ftrace_func_entry *entry;
1085	int size = 1 << hash->size_bits;
1086	int i;
1087
1088	if (!hash->count)
1089		return;
1090
1091	for (i = 0; i < size; i++) {
1092		hhd = &hash->buckets[i];
1093		hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist)
1094			free_hash_entry(hash, entry);
1095	}
1096	FTRACE_WARN_ON(hash->count);
1097}
1098
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1099static void free_ftrace_hash(struct ftrace_hash *hash)
1100{
1101	if (!hash || hash == EMPTY_HASH)
1102		return;
1103	ftrace_hash_clear(hash);
1104	kfree(hash->buckets);
1105	kfree(hash);
1106}
1107
1108static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1109{
1110	struct ftrace_hash *hash;
1111
1112	hash = container_of(rcu, struct ftrace_hash, rcu);
1113	free_ftrace_hash(hash);
1114}
1115
1116static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1117{
1118	if (!hash || hash == EMPTY_HASH)
1119		return;
1120	call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
 
 
 
 
 
 
 
1121}
1122
1123static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1124{
1125	struct ftrace_hash *hash;
1126	int size;
1127
1128	hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1129	if (!hash)
1130		return NULL;
1131
1132	size = 1 << size_bits;
1133	hash->buckets = kzalloc(sizeof(*hash->buckets) * size, GFP_KERNEL);
1134
1135	if (!hash->buckets) {
1136		kfree(hash);
1137		return NULL;
1138	}
1139
1140	hash->size_bits = size_bits;
1141
1142	return hash;
1143}
1144
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1145static struct ftrace_hash *
1146alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1147{
1148	struct ftrace_func_entry *entry;
1149	struct ftrace_hash *new_hash;
1150	struct hlist_node *tp;
1151	int size;
1152	int ret;
1153	int i;
1154
1155	new_hash = alloc_ftrace_hash(size_bits);
1156	if (!new_hash)
1157		return NULL;
1158
 
 
 
1159	/* Empty hash? */
1160	if (!hash || !hash->count)
1161		return new_hash;
1162
1163	size = 1 << hash->size_bits;
1164	for (i = 0; i < size; i++) {
1165		hlist_for_each_entry(entry, tp, &hash->buckets[i], hlist) {
1166			ret = add_hash_entry(new_hash, entry->ip);
1167			if (ret < 0)
1168				goto free_hash;
1169		}
1170	}
1171
1172	FTRACE_WARN_ON(new_hash->count != hash->count);
1173
1174	return new_hash;
1175
1176 free_hash:
1177	free_ftrace_hash(new_hash);
1178	return NULL;
1179}
1180
1181static void
1182ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1183static void
1184ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1185
1186static int
1187ftrace_hash_move(struct ftrace_ops *ops, int enable,
1188		 struct ftrace_hash **dst, struct ftrace_hash *src)
 
1189{
1190	struct ftrace_func_entry *entry;
1191	struct hlist_node *tp, *tn;
1192	struct hlist_head *hhd;
1193	struct ftrace_hash *old_hash;
1194	struct ftrace_hash *new_hash;
1195	unsigned long key;
1196	int size = src->count;
1197	int bits = 0;
1198	int ret;
1199	int i;
1200
1201	/*
1202	 * Remove the current set, update the hash and add
1203	 * them back.
1204	 */
1205	ftrace_hash_rec_disable(ops, enable);
1206
1207	/*
1208	 * If the new source is empty, just free dst and assign it
1209	 * the empty_hash.
1210	 */
1211	if (!src->count) {
1212		free_ftrace_hash_rcu(*dst);
1213		rcu_assign_pointer(*dst, EMPTY_HASH);
1214		return 0;
1215	}
1216
1217	/*
1218	 * Make the hash size about 1/2 the # found
1219	 */
1220	for (size /= 2; size; size >>= 1)
1221		bits++;
1222
1223	/* Don't allocate too much */
1224	if (bits > FTRACE_HASH_MAX_BITS)
1225		bits = FTRACE_HASH_MAX_BITS;
1226
1227	ret = -ENOMEM;
1228	new_hash = alloc_ftrace_hash(bits);
1229	if (!new_hash)
1230		goto out;
 
 
1231
1232	size = 1 << src->size_bits;
1233	for (i = 0; i < size; i++) {
1234		hhd = &src->buckets[i];
1235		hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist) {
1236			if (bits > 0)
1237				key = hash_long(entry->ip, bits);
1238			else
1239				key = 0;
1240			remove_hash_entry(src, entry);
1241			__add_hash_entry(new_hash, entry);
1242		}
1243	}
 
 
1244
1245	old_hash = *dst;
1246	rcu_assign_pointer(*dst, new_hash);
1247	free_ftrace_hash_rcu(old_hash);
 
1248
1249	ret = 0;
1250 out:
1251	/*
1252	 * Enable regardless of ret:
1253	 *  On success, we enable the new hash.
1254	 *  On failure, we re-enable the original hash.
1255	 */
1256	ftrace_hash_rec_enable(ops, enable);
 
1257
1258	return ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1259}
1260
1261/*
1262 * Test the hashes for this ops to see if we want to call
1263 * the ops->func or not.
1264 *
1265 * It's a match if the ip is in the ops->filter_hash or
1266 * the filter_hash does not exist or is empty,
1267 *  AND
1268 * the ip is not in the ops->notrace_hash.
1269 *
1270 * This needs to be called with preemption disabled as
1271 * the hashes are freed with call_rcu_sched().
1272 */
1273static int
1274ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
1275{
1276	struct ftrace_hash *filter_hash;
1277	struct ftrace_hash *notrace_hash;
1278	int ret;
1279
1280	filter_hash = rcu_dereference_raw(ops->filter_hash);
1281	notrace_hash = rcu_dereference_raw(ops->notrace_hash);
 
 
 
 
 
 
 
 
 
 
1282
1283	if ((!filter_hash || !filter_hash->count ||
1284	     ftrace_lookup_ip(filter_hash, ip)) &&
1285	    (!notrace_hash || !notrace_hash->count ||
1286	     !ftrace_lookup_ip(notrace_hash, ip)))
1287		ret = 1;
1288	else
1289		ret = 0;
1290
1291	return ret;
1292}
1293
1294/*
1295 * This is a double for. Do not use 'break' to break out of the loop,
1296 * you must use a goto.
1297 */
1298#define do_for_each_ftrace_rec(pg, rec)					\
1299	for (pg = ftrace_pages_start; pg; pg = pg->next) {		\
1300		int _____i;						\
1301		for (_____i = 0; _____i < pg->index; _____i++) {	\
1302			rec = &pg->records[_____i];
1303
1304#define while_for_each_ftrace_rec()		\
1305		}				\
1306	}
1307
1308static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1309				     int filter_hash,
1310				     bool inc)
1311{
1312	struct ftrace_hash *hash;
1313	struct ftrace_hash *other_hash;
1314	struct ftrace_page *pg;
1315	struct dyn_ftrace *rec;
 
1316	int count = 0;
1317	int all = 0;
1318
1319	/* Only update if the ops has been registered */
1320	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1321		return;
1322
1323	/*
1324	 * In the filter_hash case:
1325	 *   If the count is zero, we update all records.
1326	 *   Otherwise we just update the items in the hash.
1327	 *
1328	 * In the notrace_hash case:
1329	 *   We enable the update in the hash.
1330	 *   As disabling notrace means enabling the tracing,
1331	 *   and enabling notrace means disabling, the inc variable
1332	 *   gets inversed.
1333	 */
1334	if (filter_hash) {
1335		hash = ops->filter_hash;
1336		other_hash = ops->notrace_hash;
1337		if (!hash || !hash->count)
1338			all = 1;
1339	} else {
1340		inc = !inc;
1341		hash = ops->notrace_hash;
1342		other_hash = ops->filter_hash;
1343		/*
1344		 * If the notrace hash has no items,
1345		 * then there's nothing to do.
1346		 */
1347		if (hash && !hash->count)
1348			return;
1349	}
1350
1351	do_for_each_ftrace_rec(pg, rec) {
1352		int in_other_hash = 0;
1353		int in_hash = 0;
1354		int match = 0;
1355
 
 
 
1356		if (all) {
1357			/*
1358			 * Only the filter_hash affects all records.
1359			 * Update if the record is not in the notrace hash.
1360			 */
1361			if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1362				match = 1;
1363		} else {
1364			in_hash = hash && !!ftrace_lookup_ip(hash, rec->ip);
1365			in_other_hash = other_hash && !!ftrace_lookup_ip(other_hash, rec->ip);
1366
1367			/*
 
 
1368			 *
 
 
 
 
 
1369			 */
1370			if (filter_hash && in_hash && !in_other_hash)
1371				match = 1;
1372			else if (!filter_hash && in_hash &&
1373				 (in_other_hash || !other_hash->count))
1374				match = 1;
1375		}
1376		if (!match)
1377			continue;
1378
1379		if (inc) {
1380			rec->flags++;
1381			if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
1382				return;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1383		} else {
1384			if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
1385				return;
1386			rec->flags--;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1387		}
1388		count++;
 
 
 
 
1389		/* Shortcut, if we handled all records, we are done. */
1390		if (!all && count == hash->count)
1391			return;
1392	} while_for_each_ftrace_rec();
 
 
1393}
1394
1395static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1396				    int filter_hash)
1397{
1398	__ftrace_hash_rec_update(ops, filter_hash, 0);
1399}
1400
1401static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1402				   int filter_hash)
1403{
1404	__ftrace_hash_rec_update(ops, filter_hash, 1);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1405}
1406
1407static void ftrace_free_rec(struct dyn_ftrace *rec)
 
1408{
1409	rec->freelist = ftrace_free_records;
1410	ftrace_free_records = rec;
1411	rec->flags |= FTRACE_FL_FREE;
1412}
1413
1414static struct dyn_ftrace *ftrace_alloc_dyn_node(unsigned long ip)
 
 
 
 
 
 
 
 
 
 
 
1415{
1416	struct dyn_ftrace *rec;
 
 
1417
1418	/* First check for freed records */
1419	if (ftrace_free_records) {
1420		rec = ftrace_free_records;
1421
1422		if (unlikely(!(rec->flags & FTRACE_FL_FREE))) {
1423			FTRACE_WARN_ON_ONCE(1);
1424			ftrace_free_records = NULL;
1425			return NULL;
1426		}
1427
1428		ftrace_free_records = rec->freelist;
1429		memset(rec, 0, sizeof(*rec));
1430		return rec;
1431	}
1432
1433	if (ftrace_pages->index == ENTRIES_PER_PAGE) {
1434		if (!ftrace_pages->next) {
1435			/* allocate another page */
1436			ftrace_pages->next =
1437				(void *)get_zeroed_page(GFP_KERNEL);
1438			if (!ftrace_pages->next)
1439				return NULL;
1440		}
1441		ftrace_pages = ftrace_pages->next;
1442	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1443
1444	return &ftrace_pages->records[ftrace_pages->index++];
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1445}
1446
1447static struct dyn_ftrace *
1448ftrace_record_ip(unsigned long ip)
1449{
1450	struct dyn_ftrace *rec;
1451
1452	if (ftrace_disabled)
1453		return NULL;
1454
1455	rec = ftrace_alloc_dyn_node(ip);
1456	if (!rec)
1457		return NULL;
1458
1459	rec->ip = ip;
1460	rec->newlist = ftrace_new_addrs;
1461	ftrace_new_addrs = rec;
 
1462
1463	return rec;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1464}
1465
1466static void print_ip_ins(const char *fmt, unsigned char *p)
1467{
1468	int i;
1469
1470	printk(KERN_CONT "%s", fmt);
1471
1472	for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1473		printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1474}
1475
1476static void ftrace_bug(int failed, unsigned long ip)
 
 
 
1477{
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1478	switch (failed) {
1479	case -EFAULT:
1480		FTRACE_WARN_ON_ONCE(1);
1481		pr_info("ftrace faulted on modifying ");
1482		print_ip_sym(ip);
1483		break;
1484	case -EINVAL:
1485		FTRACE_WARN_ON_ONCE(1);
1486		pr_info("ftrace failed to modify ");
1487		print_ip_sym(ip);
1488		print_ip_ins(" actual: ", (unsigned char *)ip);
1489		printk(KERN_CONT "\n");
 
 
 
 
1490		break;
1491	case -EPERM:
1492		FTRACE_WARN_ON_ONCE(1);
1493		pr_info("ftrace faulted on writing ");
1494		print_ip_sym(ip);
1495		break;
1496	default:
1497		FTRACE_WARN_ON_ONCE(1);
1498		pr_info("ftrace faulted on unknown error ");
1499		print_ip_sym(ip);
1500	}
1501}
 
 
1502
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1503
1504/* Return 1 if the address range is reserved for ftrace */
1505int ftrace_text_reserved(void *start, void *end)
1506{
1507	struct dyn_ftrace *rec;
1508	struct ftrace_page *pg;
1509
1510	do_for_each_ftrace_rec(pg, rec) {
1511		if (rec->ip <= (unsigned long)end &&
1512		    rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
1513			return 1;
1514	} while_for_each_ftrace_rec();
1515	return 0;
1516}
1517
1518
1519static int
1520__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1521{
1522	unsigned long ftrace_addr;
1523	unsigned long flag = 0UL;
1524
1525	ftrace_addr = (unsigned long)FTRACE_ADDR;
 
 
 
1526
1527	/*
1528	 * If we are enabling tracing:
1529	 *
1530	 *   If the record has a ref count, then we need to enable it
1531	 *   because someone is using it.
1532	 *
1533	 *   Otherwise we make sure its disabled.
1534	 *
1535	 * If we are disabling tracing, then disable all records that
1536	 * are enabled.
1537	 */
1538	if (enable && (rec->flags & ~FTRACE_FL_MASK))
1539		flag = FTRACE_FL_ENABLED;
1540
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1541	/* If the state of this record hasn't changed, then do nothing */
1542	if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1543		return 0;
1544
1545	if (flag) {
1546		rec->flags |= FTRACE_FL_ENABLED;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1547		return ftrace_make_call(rec, ftrace_addr);
 
 
 
 
 
 
 
 
1548	}
1549
1550	rec->flags &= ~FTRACE_FL_ENABLED;
1551	return ftrace_make_nop(NULL, rec, ftrace_addr);
1552}
1553
1554static void ftrace_replace_code(int enable)
1555{
1556	struct dyn_ftrace *rec;
1557	struct ftrace_page *pg;
 
 
1558	int failed;
1559
1560	if (unlikely(ftrace_disabled))
1561		return;
1562
1563	do_for_each_ftrace_rec(pg, rec) {
1564		/* Skip over free records */
1565		if (rec->flags & FTRACE_FL_FREE)
1566			continue;
1567
1568		failed = __ftrace_replace_code(rec, enable);
1569		if (failed) {
1570			ftrace_bug(failed, rec->ip);
1571			/* Stop processing */
1572			return;
1573		}
 
 
1574	} while_for_each_ftrace_rec();
1575}
1576
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1577static int
1578ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1579{
1580	unsigned long ip;
1581	int ret;
1582
1583	ip = rec->ip;
1584
1585	if (unlikely(ftrace_disabled))
1586		return 0;
1587
1588	ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1589	if (ret) {
1590		ftrace_bug(ret, ip);
 
1591		return 0;
1592	}
1593	return 1;
1594}
1595
1596/*
1597 * archs can override this function if they must do something
1598 * before the modifying code is performed.
1599 */
1600int __weak ftrace_arch_code_modify_prepare(void)
1601{
1602	return 0;
1603}
1604
1605/*
1606 * archs can override this function if they must do something
1607 * after the modifying code is performed.
1608 */
1609int __weak ftrace_arch_code_modify_post_process(void)
1610{
1611	return 0;
1612}
1613
1614static int __ftrace_modify_code(void *data)
1615{
1616	int *command = data;
 
 
 
 
 
1617
1618	/*
1619	 * Do not call function tracer while we update the code.
1620	 * We are in stop machine, no worrying about races.
 
 
 
 
 
 
1621	 */
1622	function_trace_stop++;
 
 
 
 
1623
1624	if (*command & FTRACE_ENABLE_CALLS)
1625		ftrace_replace_code(1);
1626	else if (*command & FTRACE_DISABLE_CALLS)
1627		ftrace_replace_code(0);
 
 
 
 
 
 
 
 
 
 
 
1628
1629	if (*command & FTRACE_UPDATE_TRACE_FUNC)
1630		ftrace_update_ftrace_func(ftrace_trace_function);
 
 
 
 
1631
1632	if (*command & FTRACE_START_FUNC_RET)
1633		ftrace_enable_ftrace_graph_caller();
1634	else if (*command & FTRACE_STOP_FUNC_RET)
1635		ftrace_disable_ftrace_graph_caller();
1636
1637#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
1638	/*
1639	 * For archs that call ftrace_test_stop_func(), we must
1640	 * wait till after we update all the function callers
1641	 * before we update the callback. This keeps different
1642	 * ops that record different functions from corrupting
1643	 * each other.
1644	 */
1645	__ftrace_trace_function = __ftrace_trace_function_delay;
1646#endif
1647	function_trace_stop--;
1648
1649	return 0;
1650}
1651
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1652static void ftrace_run_update_code(int command)
1653{
1654	int ret;
1655
1656	ret = ftrace_arch_code_modify_prepare();
1657	FTRACE_WARN_ON(ret);
1658	if (ret)
1659		return;
1660
1661	stop_machine(__ftrace_modify_code, &command, NULL);
 
 
 
 
 
 
1662
1663	ret = ftrace_arch_code_modify_post_process();
1664	FTRACE_WARN_ON(ret);
1665}
1666
 
 
 
 
 
 
 
 
 
 
 
 
1667static ftrace_func_t saved_ftrace_func;
1668static int ftrace_start_up;
1669static int global_start_up;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1670
1671static void ftrace_startup_enable(int command)
1672{
1673	if (saved_ftrace_func != ftrace_trace_function) {
1674		saved_ftrace_func = ftrace_trace_function;
1675		command |= FTRACE_UPDATE_TRACE_FUNC;
1676	}
1677
1678	if (!command || !ftrace_enabled)
1679		return;
1680
1681	ftrace_run_update_code(command);
1682}
1683
1684static int ftrace_startup(struct ftrace_ops *ops, int command)
1685{
1686	bool hash_enable = true;
 
 
 
 
 
 
 
1687
1688	if (unlikely(ftrace_disabled))
1689		return -ENODEV;
1690
 
 
 
 
1691	ftrace_start_up++;
1692	command |= FTRACE_ENABLE_CALLS;
1693
1694	/* ops marked global share the filter hashes */
1695	if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1696		ops = &global_ops;
1697		/* Don't update hash if global is already set */
1698		if (global_start_up)
1699			hash_enable = false;
1700		global_start_up++;
 
 
 
 
 
 
 
 
 
 
 
 
1701	}
1702
1703	ops->flags |= FTRACE_OPS_FL_ENABLED;
1704	if (hash_enable)
1705		ftrace_hash_rec_enable(ops, 1);
1706
1707	ftrace_startup_enable(command);
1708
 
 
1709	return 0;
1710}
1711
1712static void ftrace_shutdown(struct ftrace_ops *ops, int command)
1713{
1714	bool hash_disable = true;
1715
1716	if (unlikely(ftrace_disabled))
1717		return;
 
 
 
 
1718
1719	ftrace_start_up--;
1720	/*
1721	 * Just warn in case of unbalance, no need to kill ftrace, it's not
1722	 * critical but the ftrace_call callers may be never nopped again after
1723	 * further ftrace uses.
1724	 */
1725	WARN_ON_ONCE(ftrace_start_up < 0);
1726
1727	if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1728		ops = &global_ops;
1729		global_start_up--;
1730		WARN_ON_ONCE(global_start_up < 0);
1731		/* Don't update hash if global still has users */
1732		if (global_start_up) {
1733			WARN_ON_ONCE(!ftrace_start_up);
1734			hash_disable = false;
1735		}
1736	}
1737
1738	if (hash_disable)
1739		ftrace_hash_rec_disable(ops, 1);
1740
1741	if (ops != &global_ops || !global_start_up)
1742		ops->flags &= ~FTRACE_OPS_FL_ENABLED;
1743
1744	if (!ftrace_start_up)
1745		command |= FTRACE_DISABLE_CALLS;
1746
1747	if (saved_ftrace_func != ftrace_trace_function) {
1748		saved_ftrace_func = ftrace_trace_function;
1749		command |= FTRACE_UPDATE_TRACE_FUNC;
1750	}
1751
1752	if (!command || !ftrace_enabled)
1753		return;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1754
1755	ftrace_run_update_code(command);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1756}
1757
1758static void ftrace_startup_sysctl(void)
1759{
 
 
1760	if (unlikely(ftrace_disabled))
1761		return;
1762
1763	/* Force update next time */
1764	saved_ftrace_func = NULL;
1765	/* ftrace_start_up is true if we want ftrace running */
1766	if (ftrace_start_up)
1767		ftrace_run_update_code(FTRACE_ENABLE_CALLS);
 
 
 
 
1768}
1769
1770static void ftrace_shutdown_sysctl(void)
1771{
 
 
1772	if (unlikely(ftrace_disabled))
1773		return;
1774
1775	/* ftrace_start_up is true if ftrace is running */
1776	if (ftrace_start_up)
1777		ftrace_run_update_code(FTRACE_DISABLE_CALLS);
 
 
 
 
1778}
1779
1780static cycle_t		ftrace_update_time;
1781static unsigned long	ftrace_update_cnt;
1782unsigned long		ftrace_update_tot_cnt;
 
 
1783
1784static int ops_traces_mod(struct ftrace_ops *ops)
1785{
1786	struct ftrace_hash *hash;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1787
1788	hash = ops->filter_hash;
1789	return !!(!hash || !hash->count);
 
 
 
 
 
 
 
 
1790}
1791
1792static int ftrace_update_code(struct module *mod)
1793{
 
1794	struct dyn_ftrace *p;
1795	cycle_t start, stop;
1796	unsigned long ref = 0;
 
 
 
 
1797
1798	/*
1799	 * When adding a module, we need to check if tracers are
1800	 * currently enabled and if they are set to trace all functions.
1801	 * If they are, we need to enable the module functions as well
1802	 * as update the reference counts for those function records.
 
 
 
 
 
1803	 */
1804	if (mod) {
1805		struct ftrace_ops *ops;
1806
1807		for (ops = ftrace_ops_list;
1808		     ops != &ftrace_list_end; ops = ops->next) {
1809			if (ops->flags & FTRACE_OPS_FL_ENABLED &&
1810			    ops_traces_mod(ops))
1811				ref++;
1812		}
1813	}
1814
1815	start = ftrace_now(raw_smp_processor_id());
1816	ftrace_update_cnt = 0;
1817
1818	while (ftrace_new_addrs) {
1819
1820		/* If something went wrong, bail without enabling anything */
1821		if (unlikely(ftrace_disabled))
1822			return -1;
1823
1824		p = ftrace_new_addrs;
1825		ftrace_new_addrs = p->newlist;
1826		p->flags = ref;
1827
1828		/*
1829		 * Do the initial record conversion from mcount jump
1830		 * to the NOP instructions.
1831		 */
1832		if (!ftrace_code_disable(mod, p)) {
1833			ftrace_free_rec(p);
1834			/* Game over */
1835			break;
1836		}
1837
1838		ftrace_update_cnt++;
1839
1840		/*
1841		 * If the tracing is enabled, go ahead and enable the record.
1842		 *
1843		 * The reason not to enable the record immediatelly is the
1844		 * inherent check of ftrace_make_nop/ftrace_make_call for
1845		 * correct previous instructions.  Making first the NOP
1846		 * conversion puts the module to the correct state, thus
1847		 * passing the ftrace_make_call check.
1848		 */
1849		if (ftrace_start_up && ref) {
1850			int failed = __ftrace_replace_code(p, 1);
1851			if (failed) {
1852				ftrace_bug(failed, p->ip);
1853				ftrace_free_rec(p);
1854			}
1855		}
1856	}
1857
1858	stop = ftrace_now(raw_smp_processor_id());
1859	ftrace_update_time = stop - start;
1860	ftrace_update_tot_cnt += ftrace_update_cnt;
1861
1862	return 0;
1863}
1864
1865static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
1866{
1867	struct ftrace_page *pg;
1868	int cnt;
1869	int i;
1870
1871	/* allocate a few pages */
1872	ftrace_pages_start = (void *)get_zeroed_page(GFP_KERNEL);
1873	if (!ftrace_pages_start)
1874		return -1;
1875
1876	/*
1877	 * Allocate a few more pages.
1878	 *
1879	 * TODO: have some parser search vmlinux before
1880	 *   final linking to find all calls to ftrace.
1881	 *   Then we can:
1882	 *    a) know how many pages to allocate.
1883	 *     and/or
1884	 *    b) set up the table then.
1885	 *
1886	 *  The dynamic code is still necessary for
1887	 *  modules.
1888	 */
 
 
1889
1890	pg = ftrace_pages = ftrace_pages_start;
 
1891
1892	cnt = num_to_init / ENTRIES_PER_PAGE;
1893	pr_info("ftrace: allocating %ld entries in %d pages\n",
1894		num_to_init, cnt + 1);
 
 
 
 
1895
1896	for (i = 0; i < cnt; i++) {
1897		pg->next = (void *)get_zeroed_page(GFP_KERNEL);
1898
1899		/* If we fail, we'll try later anyway */
1900		if (!pg->next)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1901			break;
1902
 
 
 
 
1903		pg = pg->next;
1904	}
1905
1906	return 0;
1907}
1908
1909enum {
1910	FTRACE_ITER_FILTER	= (1 << 0),
1911	FTRACE_ITER_NOTRACE	= (1 << 1),
1912	FTRACE_ITER_PRINTALL	= (1 << 2),
1913	FTRACE_ITER_HASH	= (1 << 3),
1914	FTRACE_ITER_ENABLED	= (1 << 4),
1915};
 
 
 
 
 
 
 
1916
1917#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
1918
1919struct ftrace_iterator {
1920	loff_t				pos;
1921	loff_t				func_pos;
 
1922	struct ftrace_page		*pg;
1923	struct dyn_ftrace		*func;
1924	struct ftrace_func_probe	*probe;
 
1925	struct trace_parser		parser;
1926	struct ftrace_hash		*hash;
1927	struct ftrace_ops		*ops;
1928	int				hidx;
 
 
1929	int				idx;
1930	unsigned			flags;
1931};
1932
1933static void *
1934t_hash_next(struct seq_file *m, loff_t *pos)
1935{
1936	struct ftrace_iterator *iter = m->private;
 
 
 
 
1937	struct hlist_node *hnd = NULL;
1938	struct hlist_head *hhd;
 
1939
1940	(*pos)++;
1941	iter->pos = *pos;
1942
1943	if (iter->probe)
1944		hnd = &iter->probe->node;
1945 retry:
1946	if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
 
1947		return NULL;
1948
1949	hhd = &ftrace_func_hash[iter->hidx];
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1950
1951	if (hlist_empty(hhd)) {
1952		iter->hidx++;
1953		hnd = NULL;
1954		goto retry;
1955	}
1956
1957	if (!hnd)
1958		hnd = hhd->first;
1959	else {
1960		hnd = hnd->next;
1961		if (!hnd) {
1962			iter->hidx++;
1963			goto retry;
1964		}
1965	}
1966
1967	if (WARN_ON_ONCE(!hnd))
1968		return NULL;
1969
1970	iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
1971
1972	return iter;
1973}
1974
1975static void *t_hash_start(struct seq_file *m, loff_t *pos)
1976{
1977	struct ftrace_iterator *iter = m->private;
1978	void *p = NULL;
1979	loff_t l;
1980
1981	if (iter->func_pos > *pos)
1982		return NULL;
1983
1984	iter->hidx = 0;
1985	for (l = 0; l <= (*pos - iter->func_pos); ) {
1986		p = t_hash_next(m, &l);
 
 
 
 
 
1987		if (!p)
1988			break;
1989	}
1990	if (!p)
1991		return NULL;
1992
1993	/* Only set this if we have an item */
1994	iter->flags |= FTRACE_ITER_HASH;
1995
1996	return iter;
1997}
1998
1999static int
2000t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2001{
2002	struct ftrace_func_probe *rec;
 
 
 
 
 
2003
2004	rec = iter->probe;
2005	if (WARN_ON_ONCE(!rec))
2006		return -EIO;
2007
2008	if (rec->ops->print)
2009		return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2010
2011	seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
 
2012
2013	if (rec->data)
2014		seq_printf(m, ":%p", rec->data);
2015	seq_putc(m, '\n');
2016
2017	return 0;
2018}
2019
2020static void *
2021t_next(struct seq_file *m, void *v, loff_t *pos)
2022{
2023	struct ftrace_iterator *iter = m->private;
2024	struct ftrace_ops *ops = &global_ops;
2025	struct dyn_ftrace *rec = NULL;
2026
2027	if (unlikely(ftrace_disabled))
 
 
 
 
 
 
 
2028		return NULL;
 
2029
2030	if (iter->flags & FTRACE_ITER_HASH)
2031		return t_hash_next(m, pos);
2032
2033	(*pos)++;
2034	iter->pos = iter->func_pos = *pos;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2035
2036	if (iter->flags & FTRACE_ITER_PRINTALL)
2037		return t_hash_start(m, pos);
 
 
 
 
 
 
 
 
2038
2039 retry:
2040	if (iter->idx >= iter->pg->index) {
2041		if (iter->pg->next) {
2042			iter->pg = iter->pg->next;
2043			iter->idx = 0;
2044			goto retry;
2045		}
2046	} else {
2047		rec = &iter->pg->records[iter->idx++];
2048		if ((rec->flags & FTRACE_FL_FREE) ||
2049
2050		    ((iter->flags & FTRACE_ITER_FILTER) &&
2051		     !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2052
2053		    ((iter->flags & FTRACE_ITER_NOTRACE) &&
2054		     !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2055
2056		    ((iter->flags & FTRACE_ITER_ENABLED) &&
2057		     !(rec->flags & ~FTRACE_FL_MASK))) {
2058
2059			rec = NULL;
2060			goto retry;
2061		}
2062	}
2063
2064	if (!rec)
2065		return t_hash_start(m, pos);
2066
 
2067	iter->func = rec;
2068
2069	return iter;
2070}
2071
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2072static void reset_iter_read(struct ftrace_iterator *iter)
2073{
2074	iter->pos = 0;
2075	iter->func_pos = 0;
2076	iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH);
2077}
2078
2079static void *t_start(struct seq_file *m, loff_t *pos)
2080{
2081	struct ftrace_iterator *iter = m->private;
2082	struct ftrace_ops *ops = &global_ops;
2083	void *p = NULL;
2084	loff_t l;
2085
2086	mutex_lock(&ftrace_lock);
2087
2088	if (unlikely(ftrace_disabled))
2089		return NULL;
2090
2091	/*
2092	 * If an lseek was done, then reset and start from beginning.
2093	 */
2094	if (*pos < iter->pos)
2095		reset_iter_read(iter);
2096
2097	/*
2098	 * For set_ftrace_filter reading, if we have the filter
2099	 * off, we can short cut and just print out that all
2100	 * functions are enabled.
2101	 */
2102	if (iter->flags & FTRACE_ITER_FILTER && !ops->filter_hash->count) {
 
 
2103		if (*pos > 0)
2104			return t_hash_start(m, pos);
2105		iter->flags |= FTRACE_ITER_PRINTALL;
2106		/* reset in case of seek/pread */
2107		iter->flags &= ~FTRACE_ITER_HASH;
2108		return iter;
2109	}
2110
2111	if (iter->flags & FTRACE_ITER_HASH)
2112		return t_hash_start(m, pos);
2113
2114	/*
2115	 * Unfortunately, we need to restart at ftrace_pages_start
2116	 * every time we let go of the ftrace_mutex. This is because
2117	 * those pointers can change without the lock.
2118	 */
2119	iter->pg = ftrace_pages_start;
2120	iter->idx = 0;
2121	for (l = 0; l <= *pos; ) {
2122		p = t_next(m, p, &l);
2123		if (!p)
2124			break;
2125	}
2126
2127	if (!p) {
2128		if (iter->flags & FTRACE_ITER_FILTER)
2129			return t_hash_start(m, pos);
2130
2131		return NULL;
2132	}
2133
2134	return iter;
2135}
2136
2137static void t_stop(struct seq_file *m, void *p)
2138{
2139	mutex_unlock(&ftrace_lock);
2140}
2141
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2142static int t_show(struct seq_file *m, void *v)
2143{
2144	struct ftrace_iterator *iter = m->private;
2145	struct dyn_ftrace *rec;
2146
2147	if (iter->flags & FTRACE_ITER_HASH)
2148		return t_hash_show(m, iter);
 
 
 
2149
2150	if (iter->flags & FTRACE_ITER_PRINTALL) {
2151		seq_printf(m, "#### all functions enabled ####\n");
 
 
 
2152		return 0;
2153	}
2154
2155	rec = iter->func;
2156
2157	if (!rec)
2158		return 0;
2159
2160	seq_printf(m, "%ps", (void *)rec->ip);
2161	if (iter->flags & FTRACE_ITER_ENABLED)
2162		seq_printf(m, " (%ld)",
2163			   rec->flags & ~FTRACE_FL_MASK);
2164	seq_printf(m, "\n");
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2165
2166	return 0;
2167}
2168
2169static const struct seq_operations show_ftrace_seq_ops = {
2170	.start = t_start,
2171	.next = t_next,
2172	.stop = t_stop,
2173	.show = t_show,
2174};
2175
2176static int
2177ftrace_avail_open(struct inode *inode, struct file *file)
2178{
2179	struct ftrace_iterator *iter;
2180	int ret;
2181
 
 
 
 
2182	if (unlikely(ftrace_disabled))
2183		return -ENODEV;
2184
2185	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2186	if (!iter)
2187		return -ENOMEM;
2188
2189	iter->pg = ftrace_pages_start;
 
2190
2191	ret = seq_open(file, &show_ftrace_seq_ops);
2192	if (!ret) {
2193		struct seq_file *m = file->private_data;
2194
2195		m->private = iter;
2196	} else {
2197		kfree(iter);
2198	}
2199
2200	return ret;
2201}
2202
2203static int
2204ftrace_enabled_open(struct inode *inode, struct file *file)
2205{
2206	struct ftrace_iterator *iter;
2207	int ret;
2208
2209	if (unlikely(ftrace_disabled))
2210		return -ENODEV;
 
 
 
 
 
 
2211
2212	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2213	if (!iter)
2214		return -ENOMEM;
2215
2216	iter->pg = ftrace_pages_start;
2217	iter->flags = FTRACE_ITER_ENABLED;
 
2218
2219	ret = seq_open(file, &show_ftrace_seq_ops);
2220	if (!ret) {
2221		struct seq_file *m = file->private_data;
2222
2223		m->private = iter;
2224	} else {
2225		kfree(iter);
2226	}
2227
2228	return ret;
2229}
2230
2231static void ftrace_filter_reset(struct ftrace_hash *hash)
2232{
2233	mutex_lock(&ftrace_lock);
2234	ftrace_hash_clear(hash);
2235	mutex_unlock(&ftrace_lock);
2236}
2237
2238static int
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2239ftrace_regex_open(struct ftrace_ops *ops, int flag,
2240		  struct inode *inode, struct file *file)
2241{
2242	struct ftrace_iterator *iter;
2243	struct ftrace_hash *hash;
2244	int ret = 0;
 
 
 
 
2245
2246	if (unlikely(ftrace_disabled))
2247		return -ENODEV;
2248
 
 
 
2249	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2250	if (!iter)
2251		return -ENOMEM;
2252
2253	if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2254		kfree(iter);
2255		return -ENOMEM;
2256	}
2257
2258	if (flag & FTRACE_ITER_NOTRACE)
2259		hash = ops->notrace_hash;
2260	else
2261		hash = ops->filter_hash;
2262
2263	iter->ops = ops;
2264	iter->flags = flag;
 
 
 
 
 
 
 
 
 
 
 
 
 
2265
2266	if (file->f_mode & FMODE_WRITE) {
2267		mutex_lock(&ftrace_lock);
2268		iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2269		mutex_unlock(&ftrace_lock);
 
 
 
 
 
2270
2271		if (!iter->hash) {
2272			trace_parser_put(&iter->parser);
2273			kfree(iter);
2274			return -ENOMEM;
2275		}
2276	}
2277
2278	mutex_lock(&ftrace_regex_lock);
2279
2280	if ((file->f_mode & FMODE_WRITE) &&
2281	    (file->f_flags & O_TRUNC))
2282		ftrace_filter_reset(iter->hash);
2283
2284	if (file->f_mode & FMODE_READ) {
2285		iter->pg = ftrace_pages_start;
2286
2287		ret = seq_open(file, &show_ftrace_seq_ops);
2288		if (!ret) {
2289			struct seq_file *m = file->private_data;
2290			m->private = iter;
2291		} else {
2292			/* Failed */
2293			free_ftrace_hash(iter->hash);
2294			trace_parser_put(&iter->parser);
2295			kfree(iter);
2296		}
2297	} else
2298		file->private_data = iter;
2299	mutex_unlock(&ftrace_regex_lock);
 
 
 
 
 
 
 
 
 
2300
2301	return ret;
2302}
2303
2304static int
2305ftrace_filter_open(struct inode *inode, struct file *file)
2306{
2307	return ftrace_regex_open(&global_ops, FTRACE_ITER_FILTER,
2308				 inode, file);
 
 
 
 
2309}
2310
2311static int
2312ftrace_notrace_open(struct inode *inode, struct file *file)
2313{
2314	return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE,
 
 
 
2315				 inode, file);
2316}
2317
2318static loff_t
2319ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
2320{
2321	loff_t ret;
2322
2323	if (file->f_mode & FMODE_READ)
2324		ret = seq_lseek(file, offset, origin);
2325	else
2326		file->f_pos = ret = 1;
2327
2328	return ret;
 
 
 
 
 
 
 
2329}
2330
2331static int ftrace_match(char *str, char *regex, int len, int type)
2332{
2333	int matched = 0;
2334	int slen;
2335
2336	switch (type) {
 
 
2337	case MATCH_FULL:
2338		if (strcmp(str, regex) == 0)
2339			matched = 1;
2340		break;
2341	case MATCH_FRONT_ONLY:
2342		if (strncmp(str, regex, len) == 0)
2343			matched = 1;
2344		break;
2345	case MATCH_MIDDLE_ONLY:
2346		if (strstr(str, regex))
2347			matched = 1;
2348		break;
2349	case MATCH_END_ONLY:
2350		slen = strlen(str);
2351		if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
 
 
 
 
 
2352			matched = 1;
2353		break;
2354	}
2355
2356	return matched;
2357}
2358
2359static int
2360enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2361{
2362	struct ftrace_func_entry *entry;
2363	int ret = 0;
2364
2365	entry = ftrace_lookup_ip(hash, rec->ip);
2366	if (not) {
2367		/* Do nothing if it doesn't exist */
2368		if (!entry)
2369			return 0;
2370
2371		free_hash_entry(hash, entry);
2372	} else {
2373		/* Do nothing if it exists */
2374		if (entry)
2375			return 0;
2376
2377		ret = add_hash_entry(hash, rec->ip);
2378	}
2379	return ret;
2380}
2381
2382static int
2383ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2384		    char *regex, int len, int type)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2385{
2386	char str[KSYM_SYMBOL_LEN];
2387	char *modname;
2388
2389	kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2390
2391	if (mod) {
2392		/* module lookup requires matching the module */
2393		if (!modname || strcmp(modname, mod))
 
 
 
 
 
2394			return 0;
 
2395
 
 
 
 
 
 
 
 
 
 
2396		/* blank search means to match all funcs in the mod */
2397		if (!len)
2398			return 1;
2399	}
2400
2401	return ftrace_match(str, regex, len, type);
2402}
2403
2404static int
2405match_records(struct ftrace_hash *hash, char *buff,
2406	      int len, char *mod, int not)
2407{
2408	unsigned search_len = 0;
2409	struct ftrace_page *pg;
2410	struct dyn_ftrace *rec;
2411	int type = MATCH_FULL;
2412	char *search = buff;
 
 
2413	int found = 0;
2414	int ret;
 
 
 
 
 
 
 
2415
2416	if (len) {
2417		type = filter_parse_regex(buff, len, &search, &not);
2418		search_len = strlen(search);
 
2419	}
2420
2421	mutex_lock(&ftrace_lock);
2422
2423	if (unlikely(ftrace_disabled))
2424		goto out_unlock;
2425
 
 
 
 
 
2426	do_for_each_ftrace_rec(pg, rec) {
2427
2428		if (ftrace_match_record(rec, mod, search, search_len, type)) {
2429			ret = enter_record(hash, rec, not);
 
 
 
2430			if (ret < 0) {
2431				found = ret;
2432				goto out_unlock;
2433			}
2434			found = 1;
2435		}
2436	} while_for_each_ftrace_rec();
2437 out_unlock:
2438	mutex_unlock(&ftrace_lock);
2439
2440	return found;
2441}
2442
2443static int
2444ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2445{
2446	return match_records(hash, buff, len, NULL, 0);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2447}
2448
2449static int
2450ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
 
 
 
 
 
2451{
2452	int not = 0;
 
 
 
 
2453
2454	/* blank or '*' mean the same */
2455	if (strcmp(buff, "*") == 0)
2456		buff[0] = 0;
2457
2458	/* handle the case of 'dont filter this module' */
2459	if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
2460		buff[0] = 0;
2461		not = 1;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2462	}
2463
2464	return match_records(hash, buff, strlen(buff), mod, not);
 
 
 
 
 
 
 
 
 
 
 
 
2465}
2466
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2467/*
2468 * We register the module command as a template to show others how
2469 * to register the a command as well.
2470 */
2471
2472static int
2473ftrace_mod_callback(struct ftrace_hash *hash,
2474		    char *func, char *cmd, char *param, int enable)
2475{
2476	char *mod;
2477	int ret = -EINVAL;
 
 
 
 
 
2478
2479	/*
2480	 * cmd == 'mod' because we only registered this func
2481	 * for the 'mod' ftrace_func_command.
2482	 * But if you register one func with multiple commands,
2483	 * you can tell which command was used by the cmd
2484	 * parameter.
2485	 */
 
 
2486
2487	/* we must have a module name */
2488	if (!param)
2489		return ret;
2490
2491	mod = strsep(&param, ":");
2492	if (!strlen(mod))
2493		return ret;
2494
2495	ret = ftrace_match_module_records(hash, func, mod);
2496	if (!ret)
2497		ret = -EINVAL;
2498	if (ret < 0)
2499		return ret;
2500
2501	return 0;
2502}
2503
2504static struct ftrace_func_command ftrace_mod_cmd = {
2505	.name			= "mod",
2506	.func			= ftrace_mod_callback,
2507};
2508
2509static int __init ftrace_mod_cmd_init(void)
2510{
2511	return register_ftrace_command(&ftrace_mod_cmd);
2512}
2513device_initcall(ftrace_mod_cmd_init);
2514
2515static void
2516function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
2517{
2518	struct ftrace_func_probe *entry;
2519	struct hlist_head *hhd;
2520	struct hlist_node *n;
2521	unsigned long key;
2522
2523	key = hash_long(ip, FTRACE_HASH_BITS);
2524
2525	hhd = &ftrace_func_hash[key];
2526
2527	if (hlist_empty(hhd))
2528		return;
2529
2530	/*
2531	 * Disable preemption for these calls to prevent a RCU grace
2532	 * period. This syncs the hash iteration and freeing of items
2533	 * on the hash. rcu_read_lock is too dangerous here.
2534	 */
2535	preempt_disable_notrace();
2536	hlist_for_each_entry_rcu(entry, n, hhd, node) {
2537		if (entry->ip == ip)
2538			entry->ops->func(ip, parent_ip, &entry->data);
2539	}
2540	preempt_enable_notrace();
2541}
2542
2543static struct ftrace_ops trace_probe_ops __read_mostly =
2544{
2545	.func		= function_trace_probe_call,
2546};
2547
2548static int ftrace_probe_registered;
 
 
2549
2550static void __enable_ftrace_function_probe(void)
 
 
 
 
 
2551{
2552	int ret;
2553	int i;
2554
2555	if (ftrace_probe_registered)
2556		return;
 
 
 
 
 
 
2557
2558	for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2559		struct hlist_head *hhd = &ftrace_func_hash[i];
2560		if (hhd->first)
2561			break;
2562	}
2563	/* Nothing registered? */
2564	if (i == FTRACE_FUNC_HASHSIZE)
2565		return;
 
 
 
 
 
 
 
 
2566
2567	ret = __register_ftrace_function(&trace_probe_ops);
2568	if (!ret)
2569		ret = ftrace_startup(&trace_probe_ops, 0);
2570
2571	ftrace_probe_registered = 1;
 
2572}
2573
2574static void __disable_ftrace_function_probe(void)
 
 
 
 
 
 
 
 
 
2575{
2576	int ret;
2577	int i;
2578
2579	if (!ftrace_probe_registered)
2580		return;
 
2581
2582	for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2583		struct hlist_head *hhd = &ftrace_func_hash[i];
2584		if (hhd->first)
2585			return;
2586	}
2587
2588	/* no more funcs left */
2589	ret = __unregister_ftrace_function(&trace_probe_ops);
2590	if (!ret)
2591		ftrace_shutdown(&trace_probe_ops, 0);
2592
2593	ftrace_probe_registered = 0;
2594}
2595
 
 
2596
2597static void ftrace_free_entry_rcu(struct rcu_head *rhp)
 
 
 
 
 
 
 
 
 
 
 
2598{
2599	struct ftrace_func_probe *entry =
2600		container_of(rhp, struct ftrace_func_probe, rcu);
 
 
 
 
 
 
 
 
2601
2602	if (entry->ops->free)
2603		entry->ops->free(&entry->data);
2604	kfree(entry);
 
 
2605}
2606
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2607
2608int
2609register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2610			      void *data)
 
2611{
2612	struct ftrace_func_probe *entry;
2613	struct ftrace_page *pg;
2614	struct dyn_ftrace *rec;
2615	int type, len, not;
2616	unsigned long key;
2617	int count = 0;
2618	char *search;
 
 
2619
2620	type = filter_parse_regex(glob, strlen(glob), &search, &not);
2621	len = strlen(search);
2622
2623	/* we do not support '!' for function probes */
2624	if (WARN_ON(not))
2625		return -EINVAL;
2626
 
2627	mutex_lock(&ftrace_lock);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2628
2629	if (unlikely(ftrace_disabled))
2630		goto out_unlock;
2631
2632	do_for_each_ftrace_rec(pg, rec) {
2633
2634		if (!ftrace_match_record(rec, NULL, search, len, type))
2635			continue;
 
 
 
2636
2637		entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2638		if (!entry) {
2639			/* If we did not process any, then return error */
2640			if (!count)
2641				count = -ENOMEM;
2642			goto out_unlock;
2643		}
2644
2645		count++;
 
 
 
2646
2647		entry->data = data;
2648
2649		/*
2650		 * The caller might want to do something special
2651		 * for each function we find. We call the callback
2652		 * to give the caller an opportunity to do so.
2653		 */
2654		if (ops->callback) {
2655			if (ops->callback(rec->ip, &entry->data) < 0) {
2656				/* caller does not like this func */
2657				kfree(entry);
 
 
2658				continue;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2659			}
 
2660		}
 
2661
2662		entry->ops = ops;
2663		entry->ip = rec->ip;
2664
2665		key = hash_long(entry->ip, FTRACE_HASH_BITS);
2666		hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
 
 
 
2667
2668	} while_for_each_ftrace_rec();
2669	__enable_ftrace_function_probe();
 
 
 
 
 
 
 
 
2670
2671 out_unlock:
2672	mutex_unlock(&ftrace_lock);
2673
2674	return count;
2675}
 
 
 
2676
2677enum {
2678	PROBE_TEST_FUNC		= 1,
2679	PROBE_TEST_DATA		= 2
2680};
2681
2682static void
2683__unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2684				  void *data, int flags)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2685{
2686	struct ftrace_func_probe *entry;
2687	struct hlist_node *n, *tmp;
 
 
 
 
 
 
 
2688	char str[KSYM_SYMBOL_LEN];
2689	int type = MATCH_FULL;
2690	int i, len = 0;
2691	char *search;
2692
2693	if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2694		glob = NULL;
2695	else if (glob) {
2696		int not;
2697
2698		type = filter_parse_regex(glob, strlen(glob), &search, &not);
2699		len = strlen(search);
 
2700
2701		/* we do not support '!' for function probes */
2702		if (WARN_ON(not))
2703			return;
2704	}
2705
2706	mutex_lock(&ftrace_lock);
2707	for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2708		struct hlist_head *hhd = &ftrace_func_hash[i];
 
 
 
 
 
2709
2710		hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
 
 
2711
2712			/* break up if statements for readability */
2713			if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2714				continue;
2715
2716			if ((flags & PROBE_TEST_DATA) && entry->data != data)
2717				continue;
 
2718
2719			/* do this last, since it is the most expensive */
2720			if (glob) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2721				kallsyms_lookup(entry->ip, NULL, NULL,
2722						NULL, str);
2723				if (!ftrace_match(str, glob, len, type))
2724					continue;
2725			}
2726
2727			hlist_del(&entry->node);
2728			call_rcu(&entry->rcu, ftrace_free_entry_rcu);
2729		}
2730	}
2731	__disable_ftrace_function_probe();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2732	mutex_unlock(&ftrace_lock);
2733}
2734
2735void
2736unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2737				void *data)
2738{
2739	__unregister_ftrace_function_probe(glob, ops, data,
2740					  PROBE_TEST_FUNC | PROBE_TEST_DATA);
2741}
2742
2743void
2744unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
2745{
2746	__unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
 
 
 
2747}
2748
2749void unregister_ftrace_function_probe_all(char *glob)
2750{
2751	__unregister_ftrace_function_probe(glob, NULL, NULL, 0);
 
 
 
2752}
2753
2754static LIST_HEAD(ftrace_commands);
2755static DEFINE_MUTEX(ftrace_cmd_mutex);
2756
2757int register_ftrace_command(struct ftrace_func_command *cmd)
 
 
 
 
2758{
2759	struct ftrace_func_command *p;
2760	int ret = 0;
2761
2762	mutex_lock(&ftrace_cmd_mutex);
2763	list_for_each_entry(p, &ftrace_commands, list) {
2764		if (strcmp(cmd->name, p->name) == 0) {
2765			ret = -EBUSY;
2766			goto out_unlock;
2767		}
2768	}
2769	list_add(&cmd->list, &ftrace_commands);
2770 out_unlock:
2771	mutex_unlock(&ftrace_cmd_mutex);
2772
2773	return ret;
2774}
2775
2776int unregister_ftrace_command(struct ftrace_func_command *cmd)
 
 
 
 
2777{
2778	struct ftrace_func_command *p, *n;
2779	int ret = -ENODEV;
2780
2781	mutex_lock(&ftrace_cmd_mutex);
2782	list_for_each_entry_safe(p, n, &ftrace_commands, list) {
2783		if (strcmp(cmd->name, p->name) == 0) {
2784			ret = 0;
2785			list_del_init(&p->list);
2786			goto out_unlock;
2787		}
2788	}
2789 out_unlock:
2790	mutex_unlock(&ftrace_cmd_mutex);
2791
2792	return ret;
2793}
2794
2795static int ftrace_process_regex(struct ftrace_hash *hash,
2796				char *buff, int len, int enable)
2797{
 
 
2798	char *func, *command, *next = buff;
2799	struct ftrace_func_command *p;
2800	int ret = -EINVAL;
2801
2802	func = strsep(&next, ":");
2803
2804	if (!next) {
2805		ret = ftrace_match_records(hash, func, len);
2806		if (!ret)
2807			ret = -EINVAL;
2808		if (ret < 0)
2809			return ret;
2810		return 0;
2811	}
2812
2813	/* command found */
2814
2815	command = strsep(&next, ":");
2816
2817	mutex_lock(&ftrace_cmd_mutex);
2818	list_for_each_entry(p, &ftrace_commands, list) {
2819		if (strcmp(p->name, command) == 0) {
2820			ret = p->func(hash, func, command, next, enable);
2821			goto out_unlock;
2822		}
2823	}
2824 out_unlock:
2825	mutex_unlock(&ftrace_cmd_mutex);
2826
2827	return ret;
2828}
2829
2830static ssize_t
2831ftrace_regex_write(struct file *file, const char __user *ubuf,
2832		   size_t cnt, loff_t *ppos, int enable)
2833{
2834	struct ftrace_iterator *iter;
2835	struct trace_parser *parser;
2836	ssize_t ret, read;
2837
2838	if (!cnt)
2839		return 0;
2840
2841	mutex_lock(&ftrace_regex_lock);
2842
2843	ret = -ENODEV;
2844	if (unlikely(ftrace_disabled))
2845		goto out_unlock;
2846
2847	if (file->f_mode & FMODE_READ) {
2848		struct seq_file *m = file->private_data;
2849		iter = m->private;
2850	} else
2851		iter = file->private_data;
2852
 
 
 
 
 
2853	parser = &iter->parser;
2854	read = trace_get_user(parser, ubuf, cnt, ppos);
2855
2856	if (read >= 0 && trace_parser_loaded(parser) &&
2857	    !trace_parser_cont(parser)) {
2858		ret = ftrace_process_regex(iter->hash, parser->buffer,
2859					   parser->idx, enable);
2860		trace_parser_clear(parser);
2861		if (ret)
2862			goto out_unlock;
2863	}
2864
2865	ret = read;
2866out_unlock:
2867	mutex_unlock(&ftrace_regex_lock);
2868
2869	return ret;
2870}
2871
2872static ssize_t
2873ftrace_filter_write(struct file *file, const char __user *ubuf,
2874		    size_t cnt, loff_t *ppos)
2875{
2876	return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
2877}
2878
2879static ssize_t
2880ftrace_notrace_write(struct file *file, const char __user *ubuf,
2881		     size_t cnt, loff_t *ppos)
2882{
2883	return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
2884}
2885
2886static int
2887ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
2888		 int reset, int enable)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2889{
2890	struct ftrace_hash **orig_hash;
2891	struct ftrace_hash *hash;
2892	int ret;
2893
2894	/* All global ops uses the global ops filters */
2895	if (ops->flags & FTRACE_OPS_FL_GLOBAL)
2896		ops = &global_ops;
2897
2898	if (unlikely(ftrace_disabled))
2899		return -ENODEV;
2900
 
 
2901	if (enable)
2902		orig_hash = &ops->filter_hash;
2903	else
2904		orig_hash = &ops->notrace_hash;
2905
2906	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
2907	if (!hash)
2908		return -ENOMEM;
2909
2910	mutex_lock(&ftrace_regex_lock);
2911	if (reset)
2912		ftrace_filter_reset(hash);
2913	if (buf)
2914		ftrace_match_records(hash, buf, len);
2915
2916	mutex_lock(&ftrace_lock);
2917	ret = ftrace_hash_move(ops, enable, orig_hash, hash);
2918	if (!ret && ops->flags & FTRACE_OPS_FL_ENABLED
2919	    && ftrace_enabled)
2920		ftrace_run_update_code(FTRACE_ENABLE_CALLS);
2921
 
 
 
 
 
 
 
 
 
 
 
 
2922	mutex_unlock(&ftrace_lock);
2923
2924	mutex_unlock(&ftrace_regex_lock);
 
2925
2926	free_ftrace_hash(hash);
2927	return ret;
2928}
2929
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2930/**
2931 * ftrace_set_filter - set a function to filter on in ftrace
2932 * @ops - the ops to set the filter with
2933 * @buf - the string that holds the function filter text.
2934 * @len - the length of the string.
2935 * @reset - non zero to reset all filters before applying this filter.
2936 *
2937 * Filters denote which functions should be enabled when tracing is enabled.
2938 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2939 */
2940void ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
2941		       int len, int reset)
2942{
2943	ftrace_set_regex(ops, buf, len, reset, 1);
 
2944}
2945EXPORT_SYMBOL_GPL(ftrace_set_filter);
2946
2947/**
2948 * ftrace_set_notrace - set a function to not trace in ftrace
2949 * @ops - the ops to set the notrace filter with
2950 * @buf - the string that holds the function notrace text.
2951 * @len - the length of the string.
2952 * @reset - non zero to reset all filters before applying this filter.
2953 *
2954 * Notrace Filters denote which functions should not be enabled when tracing
2955 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2956 * for tracing.
2957 */
2958void ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
2959			int len, int reset)
2960{
2961	ftrace_set_regex(ops, buf, len, reset, 0);
 
2962}
2963EXPORT_SYMBOL_GPL(ftrace_set_notrace);
2964/**
2965 * ftrace_set_filter - set a function to filter on in ftrace
2966 * @ops - the ops to set the filter with
2967 * @buf - the string that holds the function filter text.
2968 * @len - the length of the string.
2969 * @reset - non zero to reset all filters before applying this filter.
2970 *
2971 * Filters denote which functions should be enabled when tracing is enabled.
2972 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
2973 */
2974void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
2975{
2976	ftrace_set_regex(&global_ops, buf, len, reset, 1);
2977}
2978EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
2979
2980/**
2981 * ftrace_set_notrace - set a function to not trace in ftrace
2982 * @ops - the ops to set the notrace filter with
2983 * @buf - the string that holds the function notrace text.
2984 * @len - the length of the string.
2985 * @reset - non zero to reset all filters before applying this filter.
2986 *
2987 * Notrace Filters denote which functions should not be enabled when tracing
2988 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
2989 * for tracing.
2990 */
2991void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
2992{
2993	ftrace_set_regex(&global_ops, buf, len, reset, 0);
2994}
2995EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
2996
2997/*
2998 * command line interface to allow users to set filters on boot up.
2999 */
3000#define FTRACE_FILTER_SIZE		COMMAND_LINE_SIZE
3001static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3002static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3003
 
 
 
3004static int __init set_ftrace_notrace(char *str)
3005{
3006	strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
 
3007	return 1;
3008}
3009__setup("ftrace_notrace=", set_ftrace_notrace);
3010
3011static int __init set_ftrace_filter(char *str)
3012{
3013	strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
 
3014	return 1;
3015}
3016__setup("ftrace_filter=", set_ftrace_filter);
3017
3018#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3019static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3020static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
 
3021
3022static int __init set_graph_function(char *str)
3023{
3024	strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3025	return 1;
3026}
3027__setup("ftrace_graph_filter=", set_graph_function);
3028
3029static void __init set_ftrace_early_graph(char *buf)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3030{
3031	int ret;
3032	char *func;
 
 
 
 
 
3033
3034	while (buf) {
3035		func = strsep(&buf, ",");
3036		/* we allow only one expression at a time */
3037		ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3038				      func);
3039		if (ret)
3040			printk(KERN_DEBUG "ftrace: function %s not "
3041					  "traceable\n", func);
3042	}
 
 
 
 
 
3043}
3044#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3045
3046static void __init
3047set_ftrace_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3048{
3049	char *func;
3050
 
 
3051	while (buf) {
3052		func = strsep(&buf, ",");
3053		ftrace_set_regex(ops, func, strlen(func), 0, enable);
3054	}
3055}
3056
3057static void __init set_ftrace_early_filters(void)
3058{
3059	if (ftrace_filter_buf[0])
3060		set_ftrace_early_filter(&global_ops, ftrace_filter_buf, 1);
3061	if (ftrace_notrace_buf[0])
3062		set_ftrace_early_filter(&global_ops, ftrace_notrace_buf, 0);
3063#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3064	if (ftrace_graph_buf[0])
3065		set_ftrace_early_graph(ftrace_graph_buf);
 
 
3066#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3067}
3068
3069static int
3070ftrace_regex_release(struct inode *inode, struct file *file)
3071{
3072	struct seq_file *m = (struct seq_file *)file->private_data;
3073	struct ftrace_iterator *iter;
3074	struct ftrace_hash **orig_hash;
3075	struct trace_parser *parser;
3076	int filter_hash;
3077	int ret;
3078
3079	mutex_lock(&ftrace_regex_lock);
3080	if (file->f_mode & FMODE_READ) {
3081		iter = m->private;
3082
3083		seq_release(inode, file);
3084	} else
3085		iter = file->private_data;
3086
3087	parser = &iter->parser;
3088	if (trace_parser_loaded(parser)) {
3089		parser->buffer[parser->idx] = 0;
3090		ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3091	}
3092
3093	trace_parser_put(parser);
3094
 
 
3095	if (file->f_mode & FMODE_WRITE) {
3096		filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3097
3098		if (filter_hash)
3099			orig_hash = &iter->ops->filter_hash;
3100		else
3101			orig_hash = &iter->ops->notrace_hash;
 
 
3102
3103		mutex_lock(&ftrace_lock);
3104		ret = ftrace_hash_move(iter->ops, filter_hash,
3105				       orig_hash, iter->hash);
3106		if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
3107		    && ftrace_enabled)
3108			ftrace_run_update_code(FTRACE_ENABLE_CALLS);
3109
3110		mutex_unlock(&ftrace_lock);
 
 
 
3111	}
 
 
3112	free_ftrace_hash(iter->hash);
 
 
3113	kfree(iter);
3114
3115	mutex_unlock(&ftrace_regex_lock);
3116	return 0;
3117}
3118
3119static const struct file_operations ftrace_avail_fops = {
3120	.open = ftrace_avail_open,
3121	.read = seq_read,
3122	.llseek = seq_lseek,
3123	.release = seq_release_private,
3124};
3125
3126static const struct file_operations ftrace_enabled_fops = {
3127	.open = ftrace_enabled_open,
3128	.read = seq_read,
3129	.llseek = seq_lseek,
3130	.release = seq_release_private,
3131};
3132
3133static const struct file_operations ftrace_filter_fops = {
3134	.open = ftrace_filter_open,
3135	.read = seq_read,
3136	.write = ftrace_filter_write,
3137	.llseek = ftrace_regex_lseek,
3138	.release = ftrace_regex_release,
3139};
3140
3141static const struct file_operations ftrace_notrace_fops = {
3142	.open = ftrace_notrace_open,
3143	.read = seq_read,
3144	.write = ftrace_notrace_write,
3145	.llseek = ftrace_regex_lseek,
3146	.release = ftrace_regex_release,
3147};
3148
3149#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3150
3151static DEFINE_MUTEX(graph_lock);
3152
3153int ftrace_graph_count;
3154int ftrace_graph_filter_enabled;
3155unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3156
3157static void *
3158__g_next(struct seq_file *m, loff_t *pos)
3159{
3160	if (*pos >= ftrace_graph_count)
 
 
 
 
 
3161		return NULL;
3162	return &ftrace_graph_funcs[*pos];
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3163}
3164
3165static void *
3166g_next(struct seq_file *m, void *v, loff_t *pos)
3167{
3168	(*pos)++;
3169	return __g_next(m, pos);
3170}
3171
3172static void *g_start(struct seq_file *m, loff_t *pos)
3173{
 
 
3174	mutex_lock(&graph_lock);
3175
 
 
 
 
 
 
 
3176	/* Nothing, tell g_show to print all functions are enabled */
3177	if (!ftrace_graph_filter_enabled && !*pos)
3178		return (void *)1;
3179
 
 
3180	return __g_next(m, pos);
3181}
3182
3183static void g_stop(struct seq_file *m, void *p)
3184{
3185	mutex_unlock(&graph_lock);
3186}
3187
3188static int g_show(struct seq_file *m, void *v)
3189{
3190	unsigned long *ptr = v;
3191
3192	if (!ptr)
3193		return 0;
3194
3195	if (ptr == (unsigned long *)1) {
3196		seq_printf(m, "#### all functions enabled ####\n");
 
 
 
 
 
3197		return 0;
3198	}
3199
3200	seq_printf(m, "%ps\n", (void *)*ptr);
3201
3202	return 0;
3203}
3204
3205static const struct seq_operations ftrace_graph_seq_ops = {
3206	.start = g_start,
3207	.next = g_next,
3208	.stop = g_stop,
3209	.show = g_show,
3210};
3211
3212static int
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3213ftrace_graph_open(struct inode *inode, struct file *file)
3214{
3215	int ret = 0;
 
3216
3217	if (unlikely(ftrace_disabled))
3218		return -ENODEV;
3219
 
 
 
 
3220	mutex_lock(&graph_lock);
3221	if ((file->f_mode & FMODE_WRITE) &&
3222	    (file->f_flags & O_TRUNC)) {
3223		ftrace_graph_filter_enabled = 0;
3224		ftrace_graph_count = 0;
3225		memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
3226	}
 
 
 
 
3227	mutex_unlock(&graph_lock);
 
 
3228
3229	if (file->f_mode & FMODE_READ)
3230		ret = seq_open(file, &ftrace_graph_seq_ops);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3231
 
3232	return ret;
3233}
3234
3235static int
3236ftrace_graph_release(struct inode *inode, struct file *file)
3237{
3238	if (file->f_mode & FMODE_READ)
 
 
 
 
 
 
 
 
3239		seq_release(inode, file);
3240	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3241}
3242
3243static int
3244ftrace_set_func(unsigned long *array, int *idx, char *buffer)
3245{
 
3246	struct dyn_ftrace *rec;
3247	struct ftrace_page *pg;
3248	int search_len;
3249	int fail = 1;
3250	int type, not;
3251	char *search;
3252	bool exists;
3253	int i;
3254
3255	/* decode regex */
3256	type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
3257	if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
3258		return -EBUSY;
3259
3260	search_len = strlen(search);
3261
3262	mutex_lock(&ftrace_lock);
3263
3264	if (unlikely(ftrace_disabled)) {
3265		mutex_unlock(&ftrace_lock);
3266		return -ENODEV;
3267	}
3268
3269	do_for_each_ftrace_rec(pg, rec) {
3270
3271		if (rec->flags & FTRACE_FL_FREE)
3272			continue;
3273
3274		if (ftrace_match_record(rec, NULL, search, search_len, type)) {
3275			/* if it is in the array */
3276			exists = false;
3277			for (i = 0; i < *idx; i++) {
3278				if (array[i] == rec->ip) {
3279					exists = true;
3280					break;
3281				}
3282			}
3283
3284			if (!not) {
3285				fail = 0;
3286				if (!exists) {
3287					array[(*idx)++] = rec->ip;
3288					if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
3289						goto out;
3290				}
3291			} else {
3292				if (exists) {
3293					array[i] = array[--(*idx)];
3294					array[*idx] = 0;
3295					fail = 0;
3296				}
3297			}
3298		}
3299	} while_for_each_ftrace_rec();
3300out:
3301	mutex_unlock(&ftrace_lock);
3302
3303	if (fail)
3304		return -EINVAL;
3305
3306	ftrace_graph_filter_enabled = 1;
3307	return 0;
3308}
3309
3310static ssize_t
3311ftrace_graph_write(struct file *file, const char __user *ubuf,
3312		   size_t cnt, loff_t *ppos)
3313{
3314	struct trace_parser parser;
3315	ssize_t read, ret;
 
3316
3317	if (!cnt)
3318		return 0;
3319
3320	mutex_lock(&graph_lock);
3321
3322	if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
3323		ret = -ENOMEM;
3324		goto out_unlock;
3325	}
3326
3327	read = trace_get_user(&parser, ubuf, cnt, ppos);
3328
3329	if (read >= 0 && trace_parser_loaded((&parser))) {
3330		parser.buffer[parser.idx] = 0;
3331
3332		/* we allow only one expression at a time */
3333		ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3334					parser.buffer);
3335		if (ret)
3336			goto out_free;
3337	}
3338
3339	ret = read;
 
 
 
3340
3341out_free:
3342	trace_parser_put(&parser);
3343out_unlock:
3344	mutex_unlock(&graph_lock);
3345
3346	return ret;
3347}
3348
3349static const struct file_operations ftrace_graph_fops = {
3350	.open		= ftrace_graph_open,
3351	.read		= seq_read,
3352	.write		= ftrace_graph_write,
 
 
 
 
 
 
 
 
 
3353	.release	= ftrace_graph_release,
3354	.llseek		= seq_lseek,
3355};
3356#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3357
3358static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3359{
3360
3361	trace_create_file("available_filter_functions", 0444,
3362			d_tracer, NULL, &ftrace_avail_fops);
3363
3364	trace_create_file("enabled_functions", 0444,
3365			d_tracer, NULL, &ftrace_enabled_fops);
3366
3367	trace_create_file("set_ftrace_filter", 0644, d_tracer,
3368			NULL, &ftrace_filter_fops);
3369
3370	trace_create_file("set_ftrace_notrace", 0644, d_tracer,
3371				    NULL, &ftrace_notrace_fops);
3372
3373#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3374	trace_create_file("set_graph_function", 0444, d_tracer,
3375				    NULL,
3376				    &ftrace_graph_fops);
 
 
 
3377#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3378
3379	return 0;
3380}
3381
 
 
 
 
 
 
 
 
 
 
 
 
3382static int ftrace_process_locs(struct module *mod,
3383			       unsigned long *start,
3384			       unsigned long *end)
3385{
 
 
 
 
3386	unsigned long *p;
3387	unsigned long addr;
3388	unsigned long flags = 0; /* Shut up gcc */
 
 
 
 
 
 
 
 
 
 
 
 
 
3389
3390	mutex_lock(&ftrace_lock);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3391	p = start;
 
3392	while (p < end) {
3393		addr = ftrace_call_adjust(*p++);
3394		/*
3395		 * Some architecture linkers will pad between
3396		 * the different mcount_loc sections of different
3397		 * object files to satisfy alignments.
3398		 * Skip any NULL pointers.
3399		 */
3400		if (!addr)
3401			continue;
3402		ftrace_record_ip(addr);
 
 
 
 
 
 
 
 
 
3403	}
3404
 
 
 
 
 
 
3405	/*
3406	 * We only need to disable interrupts on start up
3407	 * because we are modifying code that an interrupt
3408	 * may execute, and the modification is not atomic.
3409	 * But for modules, nothing runs the code we modify
3410	 * until we are finished with it, and there's no
3411	 * reason to cause large interrupt latencies while we do it.
3412	 */
3413	if (!mod)
3414		local_irq_save(flags);
3415	ftrace_update_code(mod);
3416	if (!mod)
3417		local_irq_restore(flags);
 
 
3418	mutex_unlock(&ftrace_lock);
3419
3420	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3421}
3422
3423#ifdef CONFIG_MODULES
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3424void ftrace_release_mod(struct module *mod)
3425{
 
 
3426	struct dyn_ftrace *rec;
 
 
3427	struct ftrace_page *pg;
 
3428
3429	mutex_lock(&ftrace_lock);
3430
3431	if (ftrace_disabled)
3432		goto out_unlock;
3433
3434	do_for_each_ftrace_rec(pg, rec) {
3435		if (within_module_core(rec->ip, mod)) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3436			/*
3437			 * rec->ip is changed in ftrace_free_rec()
3438			 * It should not between s and e if record was freed.
3439			 */
3440			FTRACE_WARN_ON(rec->flags & FTRACE_FL_FREE);
3441			ftrace_free_rec(rec);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3442		}
 
3443	} while_for_each_ftrace_rec();
 
 
 
 
 
3444 out_unlock:
3445	mutex_unlock(&ftrace_lock);
 
 
3446}
3447
3448static void ftrace_init_module(struct module *mod,
3449			       unsigned long *start, unsigned long *end)
3450{
3451	if (ftrace_disabled || start == end)
3452		return;
3453	ftrace_process_locs(mod, start, end);
 
 
3454}
3455
3456static int ftrace_module_notify(struct notifier_block *self,
3457				unsigned long val, void *data)
3458{
3459	struct module *mod = data;
 
 
 
 
 
3460
3461	switch (val) {
3462	case MODULE_STATE_COMING:
3463		ftrace_init_module(mod, mod->ftrace_callsites,
3464				   mod->ftrace_callsites +
3465				   mod->num_ftrace_callsites);
3466		break;
3467	case MODULE_STATE_GOING:
3468		ftrace_release_mod(mod);
3469		break;
 
 
 
3470	}
3471
3472	return 0;
 
 
 
 
 
3473}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3474#else
3475static int ftrace_module_notify(struct notifier_block *self,
3476				unsigned long val, void *data)
 
 
 
3477{
3478	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
3479}
3480#endif /* CONFIG_MODULES */
3481
3482struct notifier_block ftrace_module_nb = {
3483	.notifier_call = ftrace_module_notify,
3484	.priority = 0,
3485};
3486
3487extern unsigned long __start_mcount_loc[];
3488extern unsigned long __stop_mcount_loc[];
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3489
3490void __init ftrace_init(void)
3491{
3492	unsigned long count, addr, flags;
 
 
3493	int ret;
3494
3495	/* Keep the ftrace pointer to the stub */
3496	addr = (unsigned long)ftrace_stub;
3497
3498	local_irq_save(flags);
3499	ftrace_dyn_arch_init(&addr);
3500	local_irq_restore(flags);
3501
3502	/* ftrace_dyn_arch_init places the return code in addr */
3503	if (addr)
3504		goto failed;
3505
3506	count = __stop_mcount_loc - __start_mcount_loc;
3507
3508	ret = ftrace_dyn_table_alloc(count);
3509	if (ret)
3510		goto failed;
 
 
 
 
3511
3512	last_ftrace_enabled = ftrace_enabled = 1;
3513
3514	ret = ftrace_process_locs(NULL,
3515				  __start_mcount_loc,
3516				  __stop_mcount_loc);
3517
3518	ret = register_module_notifier(&ftrace_module_nb);
3519	if (ret)
3520		pr_warning("Failed to register trace ftrace module notifier\n");
3521
3522	set_ftrace_early_filters();
3523
3524	return;
3525 failed:
3526	ftrace_disabled = 1;
3527}
3528
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3529#else
3530
3531static struct ftrace_ops global_ops = {
3532	.func			= ftrace_stub,
 
 
 
3533};
3534
3535static int __init ftrace_nodyn_init(void)
3536{
3537	ftrace_enabled = 1;
3538	return 0;
3539}
3540device_initcall(ftrace_nodyn_init);
3541
3542static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
3543static inline void ftrace_startup_enable(int command) { }
3544/* Keep as macros so we do not need to define the commands */
3545# define ftrace_startup(ops, command)			\
3546	({						\
3547		(ops)->flags |= FTRACE_OPS_FL_ENABLED;	\
3548		0;					\
3549	})
3550# define ftrace_shutdown(ops, command)	do { } while (0)
3551# define ftrace_startup_sysctl()	do { } while (0)
3552# define ftrace_shutdown_sysctl()	do { } while (0)
3553
3554static inline int
3555ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
3556{
3557	return 1;
3558}
3559
3560#endif /* CONFIG_DYNAMIC_FTRACE */
3561
3562static void
3563ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3564{
3565	struct ftrace_ops *op;
 
3566
3567	if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT)))
 
3568		return;
3569
3570	trace_recursion_set(TRACE_INTERNAL_BIT);
3571	/*
3572	 * Some of the ops may be dynamically allocated,
3573	 * they must be freed after a synchronize_sched().
3574	 */
3575	preempt_disable_notrace();
3576	op = rcu_dereference_raw(ftrace_ops_list);
3577	while (op != &ftrace_list_end) {
3578		if (ftrace_ops_test(op, ip))
3579			op->func(ip, parent_ip);
3580		op = rcu_dereference_raw(op->next);
3581	};
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3582	preempt_enable_notrace();
3583	trace_recursion_clear(TRACE_INTERNAL_BIT);
3584}
3585
3586static void clear_ftrace_swapper(void)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3587{
3588	struct task_struct *p;
3589	int cpu;
3590
3591	get_online_cpus();
3592	for_each_online_cpu(cpu) {
3593		p = idle_task(cpu);
3594		clear_tsk_trace_trace(p);
3595	}
3596	put_online_cpus();
3597}
3598
3599static void set_ftrace_swapper(void)
 
3600{
3601	struct task_struct *p;
3602	int cpu;
3603
3604	get_online_cpus();
3605	for_each_online_cpu(cpu) {
3606		p = idle_task(cpu);
3607		set_tsk_trace_trace(p);
3608	}
3609	put_online_cpus();
3610}
 
 
3611
3612static void clear_ftrace_pid(struct pid *pid)
 
 
 
 
 
 
3613{
3614	struct task_struct *p;
3615
3616	rcu_read_lock();
3617	do_each_pid_task(pid, PIDTYPE_PID, p) {
3618		clear_tsk_trace_trace(p);
3619	} while_each_pid_task(pid, PIDTYPE_PID, p);
3620	rcu_read_unlock();
3621
3622	put_pid(pid);
 
 
 
 
 
 
3623}
 
3624
3625static void set_ftrace_pid(struct pid *pid)
 
 
 
 
 
 
 
 
 
 
 
3626{
3627	struct task_struct *p;
 
 
 
 
 
 
3628
3629	rcu_read_lock();
3630	do_each_pid_task(pid, PIDTYPE_PID, p) {
3631		set_tsk_trace_trace(p);
3632	} while_each_pid_task(pid, PIDTYPE_PID, p);
3633	rcu_read_unlock();
3634}
3635
3636static void clear_ftrace_pid_task(struct pid *pid)
 
 
3637{
3638	if (pid == ftrace_swapper_pid)
3639		clear_ftrace_swapper();
 
 
 
 
 
 
 
 
3640	else
3641		clear_ftrace_pid(pid);
 
3642}
3643
3644static void set_ftrace_pid_task(struct pid *pid)
 
 
 
3645{
3646	if (pid == ftrace_swapper_pid)
3647		set_ftrace_swapper();
3648	else
3649		set_ftrace_pid(pid);
 
 
 
 
3650}
3651
3652static int ftrace_pid_add(int p)
 
3653{
3654	struct pid *pid;
3655	struct ftrace_pid *fpid;
3656	int ret = -EINVAL;
3657
3658	mutex_lock(&ftrace_lock);
3659
3660	if (!p)
3661		pid = ftrace_swapper_pid;
3662	else
3663		pid = find_get_pid(p);
3664
3665	if (!pid)
3666		goto out;
 
3667
3668	ret = 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
3669
3670	list_for_each_entry(fpid, &ftrace_pids, list)
3671		if (fpid->pid == pid)
3672			goto out_put;
 
 
3673
3674	ret = -ENOMEM;
 
 
 
3675
3676	fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
3677	if (!fpid)
3678		goto out_put;
3679
3680	list_add(&fpid->list, &ftrace_pids);
3681	fpid->pid = pid;
 
 
 
 
3682
3683	set_ftrace_pid_task(pid);
 
3684
3685	ftrace_update_pid_func();
3686	ftrace_startup_enable(0);
3687
3688	mutex_unlock(&ftrace_lock);
3689	return 0;
3690
3691out_put:
3692	if (pid != ftrace_swapper_pid)
3693		put_pid(pid);
3694
3695out:
3696	mutex_unlock(&ftrace_lock);
3697	return ret;
3698}
3699
3700static void ftrace_pid_reset(void)
3701{
3702	struct ftrace_pid *fpid, *safe;
3703
3704	mutex_lock(&ftrace_lock);
3705	list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
3706		struct pid *pid = fpid->pid;
3707
3708		clear_ftrace_pid_task(pid);
3709
3710		list_del(&fpid->list);
3711		kfree(fpid);
3712	}
 
 
 
 
3713
3714	ftrace_update_pid_func();
3715	ftrace_startup_enable(0);
3716
3717	mutex_unlock(&ftrace_lock);
3718}
3719
 
 
 
3720static void *fpid_start(struct seq_file *m, loff_t *pos)
 
3721{
 
 
 
3722	mutex_lock(&ftrace_lock);
 
 
 
3723
3724	if (list_empty(&ftrace_pids) && (!*pos))
3725		return (void *) 1;
3726
3727	return seq_list_start(&ftrace_pids, *pos);
3728}
3729
3730static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
3731{
3732	if (v == (void *)1)
3733		return NULL;
3734
3735	return seq_list_next(v, &ftrace_pids, pos);
 
 
 
 
3736}
3737
3738static void fpid_stop(struct seq_file *m, void *p)
 
3739{
 
3740	mutex_unlock(&ftrace_lock);
3741}
3742
3743static int fpid_show(struct seq_file *m, void *v)
3744{
3745	const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
3746
3747	if (v == (void *)1) {
3748		seq_printf(m, "no pid\n");
3749		return 0;
3750	}
3751
3752	if (fpid->pid == ftrace_swapper_pid)
3753		seq_printf(m, "swapper tasks\n");
3754	else
3755		seq_printf(m, "%u\n", pid_vnr(fpid->pid));
3756
3757	return 0;
3758}
3759
3760static const struct seq_operations ftrace_pid_sops = {
3761	.start = fpid_start,
3762	.next = fpid_next,
3763	.stop = fpid_stop,
3764	.show = fpid_show,
3765};
3766
3767static int
3768ftrace_pid_open(struct inode *inode, struct file *file)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3769{
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3770	int ret = 0;
3771
 
 
 
 
3772	if ((file->f_mode & FMODE_WRITE) &&
3773	    (file->f_flags & O_TRUNC))
3774		ftrace_pid_reset();
3775
3776	if (file->f_mode & FMODE_READ)
3777		ret = seq_open(file, &ftrace_pid_sops);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3778
3779	return ret;
3780}
3781
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3782static ssize_t
3783ftrace_pid_write(struct file *filp, const char __user *ubuf,
3784		   size_t cnt, loff_t *ppos)
3785{
3786	char buf[64], *tmp;
3787	long val;
3788	int ret;
 
 
 
3789
3790	if (cnt >= sizeof(buf))
3791		return -EINVAL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3792
3793	if (copy_from_user(&buf, ubuf, cnt))
3794		return -EFAULT;
 
 
 
 
 
 
3795
3796	buf[cnt] = 0;
 
 
 
 
 
 
 
3797
3798	/*
3799	 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
3800	 * to clean the filter quietly.
 
3801	 */
3802	tmp = strstrip(buf);
3803	if (strlen(tmp) == 0)
3804		return 1;
3805
3806	ret = strict_strtol(tmp, 10, &val);
3807	if (ret < 0)
3808		return ret;
 
 
 
 
 
 
 
3809
3810	ret = ftrace_pid_add(val);
 
 
 
 
 
3811
3812	return ret ? ret : cnt;
 
 
 
 
3813}
3814
3815static int
3816ftrace_pid_release(struct inode *inode, struct file *file)
3817{
3818	if (file->f_mode & FMODE_READ)
3819		seq_release(inode, file);
3820
3821	return 0;
 
 
3822}
3823
3824static const struct file_operations ftrace_pid_fops = {
3825	.open		= ftrace_pid_open,
3826	.write		= ftrace_pid_write,
3827	.read		= seq_read,
3828	.llseek		= seq_lseek,
3829	.release	= ftrace_pid_release,
3830};
3831
3832static __init int ftrace_init_debugfs(void)
3833{
3834	struct dentry *d_tracer;
3835
3836	d_tracer = tracing_init_dentry();
3837	if (!d_tracer)
3838		return 0;
3839
3840	ftrace_init_dyn_debugfs(d_tracer);
3841
 
 
3842	trace_create_file("set_ftrace_pid", 0644, d_tracer,
3843			    NULL, &ftrace_pid_fops);
 
 
 
3844
3845	ftrace_profile_debugfs(d_tracer);
 
 
 
 
3846
3847	return 0;
 
3848}
3849fs_initcall(ftrace_init_debugfs);
3850
3851/**
3852 * ftrace_kill - kill ftrace
3853 *
3854 * This function should be used by panic code. It stops ftrace
3855 * but in a not so nice way. If you need to simply kill ftrace
3856 * from a non-atomic section, use ftrace_kill.
3857 */
3858void ftrace_kill(void)
3859{
3860	ftrace_disabled = 1;
3861	ftrace_enabled = 0;
3862	clear_ftrace_function();
 
 
 
 
 
 
 
 
3863}
3864
3865/**
3866 * register_ftrace_function - register a function for profiling
3867 * @ops - ops structure that holds the function for profiling.
3868 *
3869 * Register a function to be called by all functions in the
3870 * kernel.
3871 *
3872 * Note: @ops->func and all the functions it calls must be labeled
3873 *       with "notrace", otherwise it will go into a
3874 *       recursive loop.
3875 */
3876int register_ftrace_function(struct ftrace_ops *ops)
3877{
3878	int ret = -1;
3879
3880	mutex_lock(&ftrace_lock);
3881
3882	if (unlikely(ftrace_disabled))
3883		goto out_unlock;
3884
3885	ret = __register_ftrace_function(ops);
3886	if (!ret)
3887		ret = ftrace_startup(ops, 0);
3888
 
3889
3890 out_unlock:
3891	mutex_unlock(&ftrace_lock);
 
3892	return ret;
3893}
3894EXPORT_SYMBOL_GPL(register_ftrace_function);
3895
3896/**
3897 * unregister_ftrace_function - unregister a function for profiling.
3898 * @ops - ops structure that holds the function to unregister
3899 *
3900 * Unregister a function that was added to be called by ftrace profiling.
3901 */
3902int unregister_ftrace_function(struct ftrace_ops *ops)
3903{
3904	int ret;
3905
3906	mutex_lock(&ftrace_lock);
3907	ret = __unregister_ftrace_function(ops);
3908	if (!ret)
3909		ftrace_shutdown(ops, 0);
3910	mutex_unlock(&ftrace_lock);
3911
3912	return ret;
3913}
3914EXPORT_SYMBOL_GPL(unregister_ftrace_function);
3915
 
 
 
 
 
 
 
 
 
 
 
 
3916int
3917ftrace_enable_sysctl(struct ctl_table *table, int write,
3918		     void __user *buffer, size_t *lenp,
3919		     loff_t *ppos)
3920{
3921	int ret = -ENODEV;
3922
3923	mutex_lock(&ftrace_lock);
3924
3925	if (unlikely(ftrace_disabled))
3926		goto out;
3927
3928	ret = proc_dointvec(table, write, buffer, lenp, ppos);
3929
3930	if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
3931		goto out;
3932
3933	last_ftrace_enabled = !!ftrace_enabled;
3934
3935	if (ftrace_enabled) {
3936
 
 
 
 
 
3937		ftrace_startup_sysctl();
3938
3939		/* we are starting ftrace again */
3940		if (ftrace_ops_list != &ftrace_list_end) {
3941			if (ftrace_ops_list->next == &ftrace_list_end)
3942				ftrace_trace_function = ftrace_ops_list->func;
3943			else
3944				ftrace_trace_function = ftrace_ops_list_func;
3945		}
3946
3947	} else {
3948		/* stopping ftrace calls (just send to ftrace_stub) */
3949		ftrace_trace_function = ftrace_stub;
3950
3951		ftrace_shutdown_sysctl();
3952	}
3953
 
3954 out:
3955	mutex_unlock(&ftrace_lock);
3956	return ret;
3957}
3958
3959#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3960
3961static int ftrace_graph_active;
3962static struct notifier_block ftrace_suspend_notifier;
3963
3964int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
3965{
3966	return 0;
3967}
3968
3969/* The callbacks that hook a function */
3970trace_func_graph_ret_t ftrace_graph_return =
3971			(trace_func_graph_ret_t)ftrace_stub;
3972trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
3973
3974/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
3975static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
3976{
3977	int i;
3978	int ret = 0;
3979	unsigned long flags;
3980	int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
3981	struct task_struct *g, *t;
3982
3983	for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
3984		ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
3985					* sizeof(struct ftrace_ret_stack),
3986					GFP_KERNEL);
3987		if (!ret_stack_list[i]) {
3988			start = 0;
3989			end = i;
3990			ret = -ENOMEM;
3991			goto free;
3992		}
3993	}
3994
3995	read_lock_irqsave(&tasklist_lock, flags);
3996	do_each_thread(g, t) {
3997		if (start == end) {
3998			ret = -EAGAIN;
3999			goto unlock;
4000		}
4001
4002		if (t->ret_stack == NULL) {
4003			atomic_set(&t->tracing_graph_pause, 0);
4004			atomic_set(&t->trace_overrun, 0);
4005			t->curr_ret_stack = -1;
4006			/* Make sure the tasks see the -1 first: */
4007			smp_wmb();
4008			t->ret_stack = ret_stack_list[start++];
4009		}
4010	} while_each_thread(g, t);
4011
4012unlock:
4013	read_unlock_irqrestore(&tasklist_lock, flags);
4014free:
4015	for (i = start; i < end; i++)
4016		kfree(ret_stack_list[i]);
4017	return ret;
4018}
4019
4020static void
4021ftrace_graph_probe_sched_switch(void *ignore,
4022			struct task_struct *prev, struct task_struct *next)
4023{
4024	unsigned long long timestamp;
4025	int index;
4026
4027	/*
4028	 * Does the user want to count the time a function was asleep.
4029	 * If so, do not update the time stamps.
4030	 */
4031	if (trace_flags & TRACE_ITER_SLEEP_TIME)
4032		return;
4033
4034	timestamp = trace_clock_local();
4035
4036	prev->ftrace_timestamp = timestamp;
4037
4038	/* only process tasks that we timestamped */
4039	if (!next->ftrace_timestamp)
4040		return;
4041
4042	/*
4043	 * Update all the counters in next to make up for the
4044	 * time next was sleeping.
4045	 */
4046	timestamp -= next->ftrace_timestamp;
4047
4048	for (index = next->curr_ret_stack; index >= 0; index--)
4049		next->ret_stack[index].calltime += timestamp;
4050}
4051
4052/* Allocate a return stack for each task */
4053static int start_graph_tracing(void)
4054{
4055	struct ftrace_ret_stack **ret_stack_list;
4056	int ret, cpu;
4057
4058	ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
4059				sizeof(struct ftrace_ret_stack *),
4060				GFP_KERNEL);
4061
4062	if (!ret_stack_list)
4063		return -ENOMEM;
4064
4065	/* The cpu_boot init_task->ret_stack will never be freed */
4066	for_each_online_cpu(cpu) {
4067		if (!idle_task(cpu)->ret_stack)
4068			ftrace_graph_init_idle_task(idle_task(cpu), cpu);
4069	}
4070
4071	do {
4072		ret = alloc_retstack_tasklist(ret_stack_list);
4073	} while (ret == -EAGAIN);
4074
4075	if (!ret) {
4076		ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4077		if (ret)
4078			pr_info("ftrace_graph: Couldn't activate tracepoint"
4079				" probe to kernel_sched_switch\n");
4080	}
4081
4082	kfree(ret_stack_list);
4083	return ret;
4084}
4085
4086/*
4087 * Hibernation protection.
4088 * The state of the current task is too much unstable during
4089 * suspend/restore to disk. We want to protect against that.
4090 */
4091static int
4092ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
4093							void *unused)
4094{
4095	switch (state) {
4096	case PM_HIBERNATION_PREPARE:
4097		pause_graph_tracing();
4098		break;
4099
4100	case PM_POST_HIBERNATION:
4101		unpause_graph_tracing();
4102		break;
4103	}
4104	return NOTIFY_DONE;
4105}
4106
4107int register_ftrace_graph(trace_func_graph_ret_t retfunc,
4108			trace_func_graph_ent_t entryfunc)
4109{
4110	int ret = 0;
4111
4112	mutex_lock(&ftrace_lock);
4113
4114	/* we currently allow only one tracer registered at a time */
4115	if (ftrace_graph_active) {
4116		ret = -EBUSY;
4117		goto out;
4118	}
4119
4120	ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
4121	register_pm_notifier(&ftrace_suspend_notifier);
4122
4123	ftrace_graph_active++;
4124	ret = start_graph_tracing();
4125	if (ret) {
4126		ftrace_graph_active--;
4127		goto out;
4128	}
4129
4130	ftrace_graph_return = retfunc;
4131	ftrace_graph_entry = entryfunc;
4132
4133	ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
4134
4135out:
4136	mutex_unlock(&ftrace_lock);
4137	return ret;
4138}
4139
4140void unregister_ftrace_graph(void)
4141{
4142	mutex_lock(&ftrace_lock);
4143
4144	if (unlikely(!ftrace_graph_active))
4145		goto out;
4146
4147	ftrace_graph_active--;
4148	ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
4149	ftrace_graph_entry = ftrace_graph_entry_stub;
4150	ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
4151	unregister_pm_notifier(&ftrace_suspend_notifier);
4152	unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4153
4154 out:
4155	mutex_unlock(&ftrace_lock);
4156}
4157
4158static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
4159
4160static void
4161graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
4162{
4163	atomic_set(&t->tracing_graph_pause, 0);
4164	atomic_set(&t->trace_overrun, 0);
4165	t->ftrace_timestamp = 0;
4166	/* make curr_ret_stack visible before we add the ret_stack */
4167	smp_wmb();
4168	t->ret_stack = ret_stack;
4169}
4170
4171/*
4172 * Allocate a return stack for the idle task. May be the first
4173 * time through, or it may be done by CPU hotplug online.
4174 */
4175void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
4176{
4177	t->curr_ret_stack = -1;
4178	/*
4179	 * The idle task has no parent, it either has its own
4180	 * stack or no stack at all.
4181	 */
4182	if (t->ret_stack)
4183		WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
4184
4185	if (ftrace_graph_active) {
4186		struct ftrace_ret_stack *ret_stack;
4187
4188		ret_stack = per_cpu(idle_ret_stack, cpu);
4189		if (!ret_stack) {
4190			ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4191					    * sizeof(struct ftrace_ret_stack),
4192					    GFP_KERNEL);
4193			if (!ret_stack)
4194				return;
4195			per_cpu(idle_ret_stack, cpu) = ret_stack;
4196		}
4197		graph_init_task(t, ret_stack);
4198	}
4199}
4200
4201/* Allocate a return stack for newly created task */
4202void ftrace_graph_init_task(struct task_struct *t)
4203{
4204	/* Make sure we do not use the parent ret_stack */
4205	t->ret_stack = NULL;
4206	t->curr_ret_stack = -1;
4207
4208	if (ftrace_graph_active) {
4209		struct ftrace_ret_stack *ret_stack;
4210
4211		ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4212				* sizeof(struct ftrace_ret_stack),
4213				GFP_KERNEL);
4214		if (!ret_stack)
4215			return;
4216		graph_init_task(t, ret_stack);
4217	}
4218}
4219
4220void ftrace_graph_exit_task(struct task_struct *t)
4221{
4222	struct ftrace_ret_stack	*ret_stack = t->ret_stack;
4223
4224	t->ret_stack = NULL;
4225	/* NULL must become visible to IRQs before we free it: */
4226	barrier();
4227
4228	kfree(ret_stack);
4229}
4230
4231void ftrace_graph_stop(void)
4232{
4233	ftrace_stop();
4234}
4235#endif