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/bsearch.h>
  26#include <linux/module.h>
  27#include <linux/ftrace.h>
  28#include <linux/sysctl.h>
  29#include <linux/slab.h>
  30#include <linux/ctype.h>
  31#include <linux/sort.h>
  32#include <linux/list.h>
  33#include <linux/hash.h>
  34#include <linux/rcupdate.h>
 
  35
  36#include <trace/events/sched.h>
  37
 
  38#include <asm/setup.h>
  39
 
  40#include "trace_output.h"
  41#include "trace_stat.h"
  42
  43#define FTRACE_WARN_ON(cond)			\
  44	({					\
  45		int ___r = cond;		\
  46		if (WARN_ON(___r))		\
  47			ftrace_kill();		\
  48		___r;				\
  49	})
  50
  51#define FTRACE_WARN_ON_ONCE(cond)		\
  52	({					\
  53		int ___r = cond;		\
  54		if (WARN_ON_ONCE(___r))		\
  55			ftrace_kill();		\
  56		___r;				\
  57	})
  58
  59/* hash bits for specific function selection */
  60#define FTRACE_HASH_BITS 7
  61#define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
  62#define FTRACE_HASH_DEFAULT_BITS 10
  63#define FTRACE_HASH_MAX_BITS 12
  64
  65#define FL_GLOBAL_CONTROL_MASK (FTRACE_OPS_FL_GLOBAL | FTRACE_OPS_FL_CONTROL)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  66
  67/* ftrace_enabled is a method to turn ftrace on or off */
  68int ftrace_enabled __read_mostly;
  69static int last_ftrace_enabled;
  70
  71/* Quick disabling of function tracer. */
  72int function_trace_stop;
 
 
  73
  74/* List for set_ftrace_pid's pids. */
  75LIST_HEAD(ftrace_pids);
  76struct ftrace_pid {
  77	struct list_head list;
  78	struct pid *pid;
  79};
 
 
 
 
 
 
 
  80
  81/*
  82 * ftrace_disabled is set when an anomaly is discovered.
  83 * ftrace_disabled is much stronger than ftrace_enabled.
  84 */
  85static int ftrace_disabled __read_mostly;
  86
  87static DEFINE_MUTEX(ftrace_lock);
  88
  89static struct ftrace_ops ftrace_list_end __read_mostly = {
  90	.func		= ftrace_stub,
  91};
  92
  93static struct ftrace_ops *ftrace_global_list __read_mostly = &ftrace_list_end;
  94static struct ftrace_ops *ftrace_control_list __read_mostly = &ftrace_list_end;
  95static struct ftrace_ops *ftrace_ops_list __read_mostly = &ftrace_list_end;
  96ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
  97static ftrace_func_t __ftrace_trace_function_delay __read_mostly = ftrace_stub;
  98ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub;
  99ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub;
 100static struct ftrace_ops global_ops;
 101static struct ftrace_ops control_ops;
 102
 103static void
 104ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip);
 
 
 
 
 
 
 105
 106/*
 107 * Traverse the ftrace_global_list, invoking all entries.  The reason that we
 108 * can use rcu_dereference_raw() is that elements removed from this list
 109 * are simply leaked, so there is no need to interact with a grace-period
 110 * mechanism.  The rcu_dereference_raw() calls are needed to handle
 111 * concurrent insertions into the ftrace_global_list.
 112 *
 113 * Silly Alpha and silly pointer-speculation compiler optimizations!
 114 */
 115static void ftrace_global_list_func(unsigned long ip,
 116				    unsigned long parent_ip)
 117{
 118	struct ftrace_ops *op;
 119
 120	if (unlikely(trace_recursion_test(TRACE_GLOBAL_BIT)))
 121		return;
 122
 123	trace_recursion_set(TRACE_GLOBAL_BIT);
 124	op = rcu_dereference_raw(ftrace_global_list); /*see above*/
 125	while (op != &ftrace_list_end) {
 126		op->func(ip, parent_ip);
 127		op = rcu_dereference_raw(op->next); /*see above*/
 128	};
 129	trace_recursion_clear(TRACE_GLOBAL_BIT);
 130}
 131
 132static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip)
 
 133{
 134	if (!test_tsk_trace_trace(current))
 
 
 135		return;
 136
 137	ftrace_pid_function(ip, parent_ip);
 138}
 139
 140static void set_ftrace_pid_function(ftrace_func_t func)
 141{
 142	/* do not set ftrace_pid_function to itself! */
 143	if (func != ftrace_pid_func)
 144		ftrace_pid_function = func;
 
 
 
 
 145}
 146
 147/**
 148 * clear_ftrace_function - reset the ftrace function
 149 *
 150 * This NULLs the ftrace function and in essence stops
 151 * tracing.  There may be lag
 152 */
 153void clear_ftrace_function(void)
 154{
 155	ftrace_trace_function = ftrace_stub;
 156	__ftrace_trace_function = ftrace_stub;
 157	__ftrace_trace_function_delay = ftrace_stub;
 158	ftrace_pid_function = ftrace_stub;
 159}
 160
 161#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 162/*
 163 * For those archs that do not test ftrace_trace_stop in their
 164 * mcount call site, we need to do it from C.
 165 */
 166static void ftrace_test_stop_func(unsigned long ip, unsigned long parent_ip)
 167{
 168	if (function_trace_stop)
 169		return;
 170
 171	__ftrace_trace_function(ip, parent_ip);
 172}
 173#endif
 174
 175static void control_ops_disable_all(struct ftrace_ops *ops)
 176{
 177	int cpu;
 178
 179	for_each_possible_cpu(cpu)
 180		*per_cpu_ptr(ops->disabled, cpu) = 1;
 181}
 182
 183static int control_ops_alloc(struct ftrace_ops *ops)
 184{
 185	int __percpu *disabled;
 186
 187	disabled = alloc_percpu(int);
 188	if (!disabled)
 189		return -ENOMEM;
 190
 191	ops->disabled = disabled;
 192	control_ops_disable_all(ops);
 193	return 0;
 194}
 195
 196static void control_ops_free(struct ftrace_ops *ops)
 197{
 198	free_percpu(ops->disabled);
 199}
 
 
 
 200
 201static void update_global_ops(void)
 202{
 203	ftrace_func_t func;
 204
 205	/*
 206	 * If there's only one function registered, then call that
 207	 * function directly. Otherwise, we need to iterate over the
 208	 * registered callers.
 209	 */
 210	if (ftrace_global_list == &ftrace_list_end ||
 211	    ftrace_global_list->next == &ftrace_list_end)
 212		func = ftrace_global_list->func;
 213	else
 214		func = ftrace_global_list_func;
 215
 216	/* If we filter on pids, update to use the pid function */
 217	if (!list_empty(&ftrace_pids)) {
 218		set_ftrace_pid_function(func);
 219		func = ftrace_pid_func;
 220	}
 221
 222	global_ops.func = func;
 223}
 224
 225static void update_ftrace_function(void)
 226{
 227	ftrace_func_t func;
 228
 229	update_global_ops();
 
 
 
 
 
 
 
 
 
 
 
 230
 
 231	/*
 232	 * If we are at the end of the list and this ops is
 233	 * not dynamic, then have the mcount trampoline call
 234	 * the function directly
 
 
 
 
 
 235	 */
 236	if (ftrace_ops_list == &ftrace_list_end ||
 237	    (ftrace_ops_list->next == &ftrace_list_end &&
 238	     !(ftrace_ops_list->flags & FTRACE_OPS_FL_DYNAMIC)))
 239		func = ftrace_ops_list->func;
 240	else
 241		func = ftrace_ops_list_func;
 
 
 
 
 
 
 
 
 242
 243#ifdef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
 244	ftrace_trace_function = func;
 245#else
 246#ifdef CONFIG_DYNAMIC_FTRACE
 247	/* do not update till all functions have been modified */
 248	__ftrace_trace_function_delay = func;
 249#else
 250	__ftrace_trace_function = func;
 251#endif
 252	ftrace_trace_function =
 253		(func == ftrace_stub) ? func : ftrace_test_stop_func;
 254#endif
 255}
 256
 257static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
 
 258{
 259	ops->next = *list;
 
 260	/*
 261	 * We are entering ops into the list but another
 262	 * CPU might be walking that list. We need to make sure
 263	 * the ops->next pointer is valid before another CPU sees
 264	 * the ops pointer included into the list.
 265	 */
 266	rcu_assign_pointer(*list, ops);
 267}
 268
 269static int remove_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
 
 270{
 271	struct ftrace_ops **p;
 272
 273	/*
 274	 * If we are removing the last function, then simply point
 275	 * to the ftrace_stub.
 276	 */
 277	if (*list == ops && ops->next == &ftrace_list_end) {
 
 
 
 278		*list = &ftrace_list_end;
 279		return 0;
 280	}
 281
 282	for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
 283		if (*p == ops)
 284			break;
 285
 286	if (*p != ops)
 287		return -1;
 288
 289	*p = (*p)->next;
 290	return 0;
 291}
 292
 293static void add_ftrace_list_ops(struct ftrace_ops **list,
 294				struct ftrace_ops *main_ops,
 295				struct ftrace_ops *ops)
 296{
 297	int first = *list == &ftrace_list_end;
 298	add_ftrace_ops(list, ops);
 299	if (first)
 300		add_ftrace_ops(&ftrace_ops_list, main_ops);
 301}
 302
 303static int remove_ftrace_list_ops(struct ftrace_ops **list,
 304				  struct ftrace_ops *main_ops,
 305				  struct ftrace_ops *ops)
 306{
 307	int ret = remove_ftrace_ops(list, ops);
 308	if (!ret && *list == &ftrace_list_end)
 309		ret = remove_ftrace_ops(&ftrace_ops_list, main_ops);
 310	return ret;
 311}
 312
 313static int __register_ftrace_function(struct ftrace_ops *ops)
 314{
 315	if (ftrace_disabled)
 316		return -ENODEV;
 317
 318	if (FTRACE_WARN_ON(ops == &global_ops))
 319		return -EINVAL;
 320
 321	if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
 322		return -EBUSY;
 323
 324	/* We don't support both control and global flags set. */
 325	if ((ops->flags & FL_GLOBAL_CONTROL_MASK) == FL_GLOBAL_CONTROL_MASK)
 
 
 
 
 
 
 326		return -EINVAL;
 327
 
 
 
 
 328	if (!core_kernel_data((unsigned long)ops))
 329		ops->flags |= FTRACE_OPS_FL_DYNAMIC;
 330
 331	if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
 332		add_ftrace_list_ops(&ftrace_global_list, &global_ops, ops);
 333		ops->flags |= FTRACE_OPS_FL_ENABLED;
 334	} else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
 335		if (control_ops_alloc(ops))
 336			return -ENOMEM;
 337		add_ftrace_list_ops(&ftrace_control_list, &control_ops, ops);
 338	} else
 339		add_ftrace_ops(&ftrace_ops_list, ops);
 340
 341	if (ftrace_enabled)
 342		update_ftrace_function();
 343
 344	return 0;
 345}
 346
 347static int __unregister_ftrace_function(struct ftrace_ops *ops)
 348{
 349	int ret;
 350
 351	if (ftrace_disabled)
 352		return -ENODEV;
 353
 354	if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
 355		return -EBUSY;
 356
 357	if (FTRACE_WARN_ON(ops == &global_ops))
 358		return -EINVAL;
 359
 360	if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
 361		ret = remove_ftrace_list_ops(&ftrace_global_list,
 362					     &global_ops, ops);
 363		if (!ret)
 364			ops->flags &= ~FTRACE_OPS_FL_ENABLED;
 365	} else if (ops->flags & FTRACE_OPS_FL_CONTROL) {
 366		ret = remove_ftrace_list_ops(&ftrace_control_list,
 367					     &control_ops, ops);
 368		if (!ret) {
 369			/*
 370			 * The ftrace_ops is now removed from the list,
 371			 * so there'll be no new users. We must ensure
 372			 * all current users are done before we free
 373			 * the control data.
 374			 */
 375			synchronize_sched();
 376			control_ops_free(ops);
 377		}
 378	} else
 379		ret = remove_ftrace_ops(&ftrace_ops_list, ops);
 380
 381	if (ret < 0)
 382		return ret;
 383
 384	if (ftrace_enabled)
 385		update_ftrace_function();
 386
 387	/*
 388	 * Dynamic ops may be freed, we must make sure that all
 389	 * callers are done before leaving this function.
 390	 */
 391	if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
 392		synchronize_sched();
 393
 394	return 0;
 395}
 396
 397static void ftrace_update_pid_func(void)
 398{
 
 
 399	/* Only do something if we are tracing something */
 400	if (ftrace_trace_function == ftrace_stub)
 401		return;
 402
 
 
 
 
 
 
 
 
 403	update_ftrace_function();
 404}
 405
 406#ifdef CONFIG_FUNCTION_PROFILER
 407struct ftrace_profile {
 408	struct hlist_node		node;
 409	unsigned long			ip;
 410	unsigned long			counter;
 411#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 412	unsigned long long		time;
 413	unsigned long long		time_squared;
 414#endif
 415};
 416
 417struct ftrace_profile_page {
 418	struct ftrace_profile_page	*next;
 419	unsigned long			index;
 420	struct ftrace_profile		records[];
 421};
 422
 423struct ftrace_profile_stat {
 424	atomic_t			disabled;
 425	struct hlist_head		*hash;
 426	struct ftrace_profile_page	*pages;
 427	struct ftrace_profile_page	*start;
 428	struct tracer_stat		stat;
 429};
 430
 431#define PROFILE_RECORDS_SIZE						\
 432	(PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
 433
 434#define PROFILES_PER_PAGE					\
 435	(PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
 436
 437static int ftrace_profile_bits __read_mostly;
 438static int ftrace_profile_enabled __read_mostly;
 439
 440/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
 441static DEFINE_MUTEX(ftrace_profile_lock);
 442
 443static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
 444
 445#define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
 
 446
 447static void *
 448function_stat_next(void *v, int idx)
 449{
 450	struct ftrace_profile *rec = v;
 451	struct ftrace_profile_page *pg;
 452
 453	pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
 454
 455 again:
 456	if (idx != 0)
 457		rec++;
 458
 459	if ((void *)rec >= (void *)&pg->records[pg->index]) {
 460		pg = pg->next;
 461		if (!pg)
 462			return NULL;
 463		rec = &pg->records[0];
 464		if (!rec->counter)
 465			goto again;
 466	}
 467
 468	return rec;
 469}
 470
 471static void *function_stat_start(struct tracer_stat *trace)
 472{
 473	struct ftrace_profile_stat *stat =
 474		container_of(trace, struct ftrace_profile_stat, stat);
 475
 476	if (!stat || !stat->start)
 477		return NULL;
 478
 479	return function_stat_next(&stat->start->records[0], 0);
 480}
 481
 482#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 483/* function graph compares on total time */
 484static int function_stat_cmp(void *p1, void *p2)
 485{
 486	struct ftrace_profile *a = p1;
 487	struct ftrace_profile *b = p2;
 488
 489	if (a->time < b->time)
 490		return -1;
 491	if (a->time > b->time)
 492		return 1;
 493	else
 494		return 0;
 495}
 496#else
 497/* not function graph compares against hits */
 498static int function_stat_cmp(void *p1, void *p2)
 499{
 500	struct ftrace_profile *a = p1;
 501	struct ftrace_profile *b = p2;
 502
 503	if (a->counter < b->counter)
 504		return -1;
 505	if (a->counter > b->counter)
 506		return 1;
 507	else
 508		return 0;
 509}
 510#endif
 511
 512static int function_stat_headers(struct seq_file *m)
 513{
 514#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 515	seq_printf(m, "  Function                               "
 516		   "Hit    Time            Avg             s^2\n"
 517		      "  --------                               "
 518		   "---    ----            ---             ---\n");
 519#else
 520	seq_printf(m, "  Function                               Hit\n"
 521		      "  --------                               ---\n");
 522#endif
 523	return 0;
 524}
 525
 526static int function_stat_show(struct seq_file *m, void *v)
 527{
 528	struct ftrace_profile *rec = v;
 529	char str[KSYM_SYMBOL_LEN];
 530	int ret = 0;
 531#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 532	static struct trace_seq s;
 533	unsigned long long avg;
 534	unsigned long long stddev;
 535#endif
 536	mutex_lock(&ftrace_profile_lock);
 537
 538	/* we raced with function_profile_reset() */
 539	if (unlikely(rec->counter == 0)) {
 540		ret = -EBUSY;
 541		goto out;
 542	}
 543
 
 
 
 
 
 
 
 544	kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 545	seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
 546
 547#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 548	seq_printf(m, "    ");
 549	avg = rec->time;
 550	do_div(avg, rec->counter);
 551
 552	/* Sample standard deviation (s^2) */
 553	if (rec->counter <= 1)
 554		stddev = 0;
 555	else {
 556		stddev = rec->time_squared - rec->counter * avg * avg;
 
 
 
 
 
 
 557		/*
 558		 * Divide only 1000 for ns^2 -> us^2 conversion.
 559		 * trace_print_graph_duration will divide 1000 again.
 560		 */
 561		do_div(stddev, (rec->counter - 1) * 1000);
 562	}
 563
 564	trace_seq_init(&s);
 565	trace_print_graph_duration(rec->time, &s);
 566	trace_seq_puts(&s, "    ");
 567	trace_print_graph_duration(avg, &s);
 568	trace_seq_puts(&s, "    ");
 569	trace_print_graph_duration(stddev, &s);
 570	trace_print_seq(m, &s);
 571#endif
 572	seq_putc(m, '\n');
 573out:
 574	mutex_unlock(&ftrace_profile_lock);
 575
 576	return ret;
 577}
 578
 579static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
 580{
 581	struct ftrace_profile_page *pg;
 582
 583	pg = stat->pages = stat->start;
 584
 585	while (pg) {
 586		memset(pg->records, 0, PROFILE_RECORDS_SIZE);
 587		pg->index = 0;
 588		pg = pg->next;
 589	}
 590
 591	memset(stat->hash, 0,
 592	       FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
 593}
 594
 595int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
 596{
 597	struct ftrace_profile_page *pg;
 598	int functions;
 599	int pages;
 600	int i;
 601
 602	/* If we already allocated, do nothing */
 603	if (stat->pages)
 604		return 0;
 605
 606	stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
 607	if (!stat->pages)
 608		return -ENOMEM;
 609
 610#ifdef CONFIG_DYNAMIC_FTRACE
 611	functions = ftrace_update_tot_cnt;
 612#else
 613	/*
 614	 * We do not know the number of functions that exist because
 615	 * dynamic tracing is what counts them. With past experience
 616	 * we have around 20K functions. That should be more than enough.
 617	 * It is highly unlikely we will execute every function in
 618	 * the kernel.
 619	 */
 620	functions = 20000;
 621#endif
 622
 623	pg = stat->start = stat->pages;
 624
 625	pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
 626
 627	for (i = 0; i < pages; i++) {
 628		pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 629		if (!pg->next)
 630			goto out_free;
 631		pg = pg->next;
 632	}
 633
 634	return 0;
 635
 636 out_free:
 637	pg = stat->start;
 638	while (pg) {
 639		unsigned long tmp = (unsigned long)pg;
 640
 641		pg = pg->next;
 642		free_page(tmp);
 643	}
 644
 645	free_page((unsigned long)stat->pages);
 646	stat->pages = NULL;
 647	stat->start = NULL;
 648
 649	return -ENOMEM;
 650}
 651
 652static int ftrace_profile_init_cpu(int cpu)
 653{
 654	struct ftrace_profile_stat *stat;
 655	int size;
 656
 657	stat = &per_cpu(ftrace_profile_stats, cpu);
 658
 659	if (stat->hash) {
 660		/* If the profile is already created, simply reset it */
 661		ftrace_profile_reset(stat);
 662		return 0;
 663	}
 664
 665	/*
 666	 * We are profiling all functions, but usually only a few thousand
 667	 * functions are hit. We'll make a hash of 1024 items.
 668	 */
 669	size = FTRACE_PROFILE_HASH_SIZE;
 670
 671	stat->hash = kzalloc(sizeof(struct hlist_head) * size, GFP_KERNEL);
 672
 673	if (!stat->hash)
 674		return -ENOMEM;
 675
 676	if (!ftrace_profile_bits) {
 677		size--;
 678
 679		for (; size; size >>= 1)
 680			ftrace_profile_bits++;
 681	}
 682
 683	/* Preallocate the function profiling pages */
 684	if (ftrace_profile_pages_init(stat) < 0) {
 685		kfree(stat->hash);
 686		stat->hash = NULL;
 687		return -ENOMEM;
 688	}
 689
 690	return 0;
 691}
 692
 693static int ftrace_profile_init(void)
 694{
 695	int cpu;
 696	int ret = 0;
 697
 698	for_each_online_cpu(cpu) {
 699		ret = ftrace_profile_init_cpu(cpu);
 700		if (ret)
 701			break;
 702	}
 703
 704	return ret;
 705}
 706
 707/* interrupts must be disabled */
 708static struct ftrace_profile *
 709ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
 710{
 711	struct ftrace_profile *rec;
 712	struct hlist_head *hhd;
 713	struct hlist_node *n;
 714	unsigned long key;
 715
 716	key = hash_long(ip, ftrace_profile_bits);
 717	hhd = &stat->hash[key];
 718
 719	if (hlist_empty(hhd))
 720		return NULL;
 721
 722	hlist_for_each_entry_rcu(rec, n, hhd, node) {
 723		if (rec->ip == ip)
 724			return rec;
 725	}
 726
 727	return NULL;
 728}
 729
 730static void ftrace_add_profile(struct ftrace_profile_stat *stat,
 731			       struct ftrace_profile *rec)
 732{
 733	unsigned long key;
 734
 735	key = hash_long(rec->ip, ftrace_profile_bits);
 736	hlist_add_head_rcu(&rec->node, &stat->hash[key]);
 737}
 738
 739/*
 740 * The memory is already allocated, this simply finds a new record to use.
 741 */
 742static struct ftrace_profile *
 743ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
 744{
 745	struct ftrace_profile *rec = NULL;
 746
 747	/* prevent recursion (from NMIs) */
 748	if (atomic_inc_return(&stat->disabled) != 1)
 749		goto out;
 750
 751	/*
 752	 * Try to find the function again since an NMI
 753	 * could have added it
 754	 */
 755	rec = ftrace_find_profiled_func(stat, ip);
 756	if (rec)
 757		goto out;
 758
 759	if (stat->pages->index == PROFILES_PER_PAGE) {
 760		if (!stat->pages->next)
 761			goto out;
 762		stat->pages = stat->pages->next;
 763	}
 764
 765	rec = &stat->pages->records[stat->pages->index++];
 766	rec->ip = ip;
 767	ftrace_add_profile(stat, rec);
 768
 769 out:
 770	atomic_dec(&stat->disabled);
 771
 772	return rec;
 773}
 774
 775static void
 776function_profile_call(unsigned long ip, unsigned long parent_ip)
 
 777{
 778	struct ftrace_profile_stat *stat;
 779	struct ftrace_profile *rec;
 780	unsigned long flags;
 781
 782	if (!ftrace_profile_enabled)
 783		return;
 784
 785	local_irq_save(flags);
 786
 787	stat = &__get_cpu_var(ftrace_profile_stats);
 788	if (!stat->hash || !ftrace_profile_enabled)
 789		goto out;
 790
 791	rec = ftrace_find_profiled_func(stat, ip);
 792	if (!rec) {
 793		rec = ftrace_profile_alloc(stat, ip);
 794		if (!rec)
 795			goto out;
 796	}
 797
 798	rec->counter++;
 799 out:
 800	local_irq_restore(flags);
 801}
 802
 803#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 
 
 
 
 
 
 
 804static int profile_graph_entry(struct ftrace_graph_ent *trace)
 805{
 806	function_profile_call(trace->func, 0);
 
 
 
 
 
 
 
 
 
 
 
 807	return 1;
 808}
 809
 810static void profile_graph_return(struct ftrace_graph_ret *trace)
 811{
 
 812	struct ftrace_profile_stat *stat;
 813	unsigned long long calltime;
 814	struct ftrace_profile *rec;
 815	unsigned long flags;
 816
 817	local_irq_save(flags);
 818	stat = &__get_cpu_var(ftrace_profile_stats);
 819	if (!stat->hash || !ftrace_profile_enabled)
 820		goto out;
 821
 822	/* If the calltime was zero'd ignore it */
 823	if (!trace->calltime)
 824		goto out;
 825
 826	calltime = trace->rettime - trace->calltime;
 827
 828	if (!(trace_flags & TRACE_ITER_GRAPH_TIME)) {
 829		int index;
 830
 831		index = trace->depth;
 832
 833		/* Append this call time to the parent time to subtract */
 834		if (index)
 835			current->ret_stack[index - 1].subtime += calltime;
 836
 837		if (current->ret_stack[index].subtime < calltime)
 838			calltime -= current->ret_stack[index].subtime;
 
 
 839		else
 840			calltime = 0;
 841	}
 842
 843	rec = ftrace_find_profiled_func(stat, trace->func);
 844	if (rec) {
 845		rec->time += calltime;
 846		rec->time_squared += calltime * calltime;
 847	}
 848
 849 out:
 850	local_irq_restore(flags);
 851}
 852
 
 
 
 
 
 853static int register_ftrace_profiler(void)
 854{
 855	return register_ftrace_graph(&profile_graph_return,
 856				     &profile_graph_entry);
 857}
 858
 859static void unregister_ftrace_profiler(void)
 860{
 861	unregister_ftrace_graph();
 862}
 863#else
 864static struct ftrace_ops ftrace_profile_ops __read_mostly = {
 865	.func		= function_profile_call,
 
 
 866};
 867
 868static int register_ftrace_profiler(void)
 869{
 870	return register_ftrace_function(&ftrace_profile_ops);
 871}
 872
 873static void unregister_ftrace_profiler(void)
 874{
 875	unregister_ftrace_function(&ftrace_profile_ops);
 876}
 877#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 878
 879static ssize_t
 880ftrace_profile_write(struct file *filp, const char __user *ubuf,
 881		     size_t cnt, loff_t *ppos)
 882{
 883	unsigned long val;
 884	int ret;
 885
 886	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
 887	if (ret)
 888		return ret;
 889
 890	val = !!val;
 891
 892	mutex_lock(&ftrace_profile_lock);
 893	if (ftrace_profile_enabled ^ val) {
 894		if (val) {
 895			ret = ftrace_profile_init();
 896			if (ret < 0) {
 897				cnt = ret;
 898				goto out;
 899			}
 900
 901			ret = register_ftrace_profiler();
 902			if (ret < 0) {
 903				cnt = ret;
 904				goto out;
 905			}
 906			ftrace_profile_enabled = 1;
 907		} else {
 908			ftrace_profile_enabled = 0;
 909			/*
 910			 * unregister_ftrace_profiler calls stop_machine
 911			 * so this acts like an synchronize_sched.
 912			 */
 913			unregister_ftrace_profiler();
 914		}
 915	}
 916 out:
 917	mutex_unlock(&ftrace_profile_lock);
 918
 919	*ppos += cnt;
 920
 921	return cnt;
 922}
 923
 924static ssize_t
 925ftrace_profile_read(struct file *filp, char __user *ubuf,
 926		     size_t cnt, loff_t *ppos)
 927{
 928	char buf[64];		/* big enough to hold a number */
 929	int r;
 930
 931	r = sprintf(buf, "%u\n", ftrace_profile_enabled);
 932	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 933}
 934
 935static const struct file_operations ftrace_profile_fops = {
 936	.open		= tracing_open_generic,
 937	.read		= ftrace_profile_read,
 938	.write		= ftrace_profile_write,
 939	.llseek		= default_llseek,
 940};
 941
 942/* used to initialize the real stat files */
 943static struct tracer_stat function_stats __initdata = {
 944	.name		= "functions",
 945	.stat_start	= function_stat_start,
 946	.stat_next	= function_stat_next,
 947	.stat_cmp	= function_stat_cmp,
 948	.stat_headers	= function_stat_headers,
 949	.stat_show	= function_stat_show
 950};
 951
 952static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
 953{
 954	struct ftrace_profile_stat *stat;
 955	struct dentry *entry;
 956	char *name;
 957	int ret;
 958	int cpu;
 959
 960	for_each_possible_cpu(cpu) {
 961		stat = &per_cpu(ftrace_profile_stats, cpu);
 962
 963		/* allocate enough for function name + cpu number */
 964		name = kmalloc(32, GFP_KERNEL);
 965		if (!name) {
 966			/*
 967			 * The files created are permanent, if something happens
 968			 * we still do not free memory.
 969			 */
 970			WARN(1,
 971			     "Could not allocate stat file for cpu %d\n",
 972			     cpu);
 973			return;
 974		}
 975		stat->stat = function_stats;
 976		snprintf(name, 32, "function%d", cpu);
 977		stat->stat.name = name;
 978		ret = register_stat_tracer(&stat->stat);
 979		if (ret) {
 980			WARN(1,
 981			     "Could not register function stat for cpu %d\n",
 982			     cpu);
 983			kfree(name);
 984			return;
 985		}
 986	}
 987
 988	entry = debugfs_create_file("function_profile_enabled", 0644,
 989				    d_tracer, NULL, &ftrace_profile_fops);
 990	if (!entry)
 991		pr_warning("Could not create debugfs "
 992			   "'function_profile_enabled' entry\n");
 993}
 994
 995#else /* CONFIG_FUNCTION_PROFILER */
 996static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
 997{
 998}
 999#endif /* CONFIG_FUNCTION_PROFILER */
1000
1001static struct pid * const ftrace_swapper_pid = &init_struct_pid;
1002
1003#ifdef CONFIG_DYNAMIC_FTRACE
1004
 
 
 
 
 
 
 
 
1005#ifndef CONFIG_FTRACE_MCOUNT_RECORD
1006# error Dynamic ftrace depends on MCOUNT_RECORD
1007#endif
1008
1009static struct hlist_head ftrace_func_hash[FTRACE_FUNC_HASHSIZE] __read_mostly;
1010
1011struct ftrace_func_probe {
1012	struct hlist_node	node;
1013	struct ftrace_probe_ops	*ops;
1014	unsigned long		flags;
1015	unsigned long		ip;
1016	void			*data;
1017	struct rcu_head		rcu;
1018};
1019
1020struct ftrace_func_entry {
1021	struct hlist_node hlist;
1022	unsigned long ip;
1023};
1024
1025struct ftrace_hash {
1026	unsigned long		size_bits;
1027	struct hlist_head	*buckets;
1028	unsigned long		count;
1029	struct rcu_head		rcu;
 
 
1030};
1031
1032/*
1033 * We make these constant because no one should touch them,
1034 * but they are used as the default "empty hash", to avoid allocating
1035 * it all the time. These are in a read only section such that if
1036 * anyone does try to modify it, it will cause an exception.
1037 */
1038static const struct hlist_head empty_buckets[1];
1039static const struct ftrace_hash empty_hash = {
1040	.buckets = (struct hlist_head *)empty_buckets,
1041};
1042#define EMPTY_HASH	((struct ftrace_hash *)&empty_hash)
1043
1044static struct ftrace_ops global_ops = {
1045	.func			= ftrace_stub,
1046	.notrace_hash		= EMPTY_HASH,
1047	.filter_hash		= EMPTY_HASH,
 
 
 
 
1048};
1049
1050static DEFINE_MUTEX(ftrace_regex_lock);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1051
1052struct ftrace_page {
1053	struct ftrace_page	*next;
1054	struct dyn_ftrace	*records;
1055	int			index;
1056	int			size;
1057};
1058
1059static struct ftrace_page *ftrace_new_pgs;
1060
1061#define ENTRY_SIZE sizeof(struct dyn_ftrace)
1062#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1063
1064/* estimate from running different kernels */
1065#define NR_TO_INIT		10000
1066
1067static struct ftrace_page	*ftrace_pages_start;
1068static struct ftrace_page	*ftrace_pages;
1069
1070static bool ftrace_hash_empty(struct ftrace_hash *hash)
 
1071{
1072	return !hash || !hash->count;
 
 
 
1073}
1074
1075static struct ftrace_func_entry *
1076ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
 
1077{
1078	unsigned long key;
1079	struct ftrace_func_entry *entry;
1080	struct hlist_head *hhd;
1081	struct hlist_node *n;
1082
1083	if (ftrace_hash_empty(hash))
1084		return NULL;
1085
1086	if (hash->size_bits > 0)
1087		key = hash_long(ip, hash->size_bits);
1088	else
1089		key = 0;
1090
 
1091	hhd = &hash->buckets[key];
1092
1093	hlist_for_each_entry_rcu(entry, n, hhd, hlist) {
1094		if (entry->ip == ip)
1095			return entry;
1096	}
1097	return NULL;
1098}
1099
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1100static void __add_hash_entry(struct ftrace_hash *hash,
1101			     struct ftrace_func_entry *entry)
1102{
1103	struct hlist_head *hhd;
1104	unsigned long key;
1105
1106	if (hash->size_bits)
1107		key = hash_long(entry->ip, hash->size_bits);
1108	else
1109		key = 0;
1110
1111	hhd = &hash->buckets[key];
1112	hlist_add_head(&entry->hlist, hhd);
1113	hash->count++;
1114}
1115
1116static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1117{
1118	struct ftrace_func_entry *entry;
1119
1120	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1121	if (!entry)
1122		return -ENOMEM;
1123
1124	entry->ip = ip;
1125	__add_hash_entry(hash, entry);
1126
1127	return 0;
1128}
1129
1130static void
1131free_hash_entry(struct ftrace_hash *hash,
1132		  struct ftrace_func_entry *entry)
1133{
1134	hlist_del(&entry->hlist);
1135	kfree(entry);
1136	hash->count--;
1137}
1138
1139static void
1140remove_hash_entry(struct ftrace_hash *hash,
1141		  struct ftrace_func_entry *entry)
1142{
1143	hlist_del(&entry->hlist);
1144	hash->count--;
1145}
1146
1147static void ftrace_hash_clear(struct ftrace_hash *hash)
1148{
1149	struct hlist_head *hhd;
1150	struct hlist_node *tp, *tn;
1151	struct ftrace_func_entry *entry;
1152	int size = 1 << hash->size_bits;
1153	int i;
1154
1155	if (!hash->count)
1156		return;
1157
1158	for (i = 0; i < size; i++) {
1159		hhd = &hash->buckets[i];
1160		hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist)
1161			free_hash_entry(hash, entry);
1162	}
1163	FTRACE_WARN_ON(hash->count);
1164}
1165
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1166static void free_ftrace_hash(struct ftrace_hash *hash)
1167{
1168	if (!hash || hash == EMPTY_HASH)
1169		return;
1170	ftrace_hash_clear(hash);
1171	kfree(hash->buckets);
1172	kfree(hash);
1173}
1174
1175static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1176{
1177	struct ftrace_hash *hash;
1178
1179	hash = container_of(rcu, struct ftrace_hash, rcu);
1180	free_ftrace_hash(hash);
1181}
1182
1183static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1184{
1185	if (!hash || hash == EMPTY_HASH)
1186		return;
1187	call_rcu_sched(&hash->rcu, __free_ftrace_hash_rcu);
1188}
1189
1190void ftrace_free_filter(struct ftrace_ops *ops)
1191{
1192	free_ftrace_hash(ops->filter_hash);
1193	free_ftrace_hash(ops->notrace_hash);
 
1194}
1195
1196static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1197{
1198	struct ftrace_hash *hash;
1199	int size;
1200
1201	hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1202	if (!hash)
1203		return NULL;
1204
1205	size = 1 << size_bits;
1206	hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1207
1208	if (!hash->buckets) {
1209		kfree(hash);
1210		return NULL;
1211	}
1212
1213	hash->size_bits = size_bits;
1214
1215	return hash;
1216}
1217
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1218static struct ftrace_hash *
1219alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1220{
1221	struct ftrace_func_entry *entry;
1222	struct ftrace_hash *new_hash;
1223	struct hlist_node *tp;
1224	int size;
1225	int ret;
1226	int i;
1227
1228	new_hash = alloc_ftrace_hash(size_bits);
1229	if (!new_hash)
1230		return NULL;
1231
 
 
 
1232	/* Empty hash? */
1233	if (ftrace_hash_empty(hash))
1234		return new_hash;
1235
1236	size = 1 << hash->size_bits;
1237	for (i = 0; i < size; i++) {
1238		hlist_for_each_entry(entry, tp, &hash->buckets[i], hlist) {
1239			ret = add_hash_entry(new_hash, entry->ip);
1240			if (ret < 0)
1241				goto free_hash;
1242		}
1243	}
1244
1245	FTRACE_WARN_ON(new_hash->count != hash->count);
1246
1247	return new_hash;
1248
1249 free_hash:
1250	free_ftrace_hash(new_hash);
1251	return NULL;
1252}
1253
1254static void
1255ftrace_hash_rec_disable(struct ftrace_ops *ops, int filter_hash);
1256static void
1257ftrace_hash_rec_enable(struct ftrace_ops *ops, int filter_hash);
1258
1259static int
1260ftrace_hash_move(struct ftrace_ops *ops, int enable,
1261		 struct ftrace_hash **dst, struct ftrace_hash *src)
 
 
1262{
1263	struct ftrace_func_entry *entry;
1264	struct hlist_node *tp, *tn;
1265	struct hlist_head *hhd;
1266	struct ftrace_hash *old_hash;
1267	struct ftrace_hash *new_hash;
1268	unsigned long key;
1269	int size = src->count;
1270	int bits = 0;
1271	int ret;
1272	int i;
1273
1274	/*
1275	 * Remove the current set, update the hash and add
1276	 * them back.
1277	 */
1278	ftrace_hash_rec_disable(ops, enable);
1279
1280	/*
1281	 * If the new source is empty, just free dst and assign it
1282	 * the empty_hash.
1283	 */
1284	if (!src->count) {
1285		free_ftrace_hash_rcu(*dst);
1286		rcu_assign_pointer(*dst, EMPTY_HASH);
1287		/* still need to update the function records */
1288		ret = 0;
1289		goto out;
1290	}
1291
1292	/*
1293	 * Make the hash size about 1/2 the # found
1294	 */
1295	for (size /= 2; size; size >>= 1)
1296		bits++;
1297
1298	/* Don't allocate too much */
1299	if (bits > FTRACE_HASH_MAX_BITS)
1300		bits = FTRACE_HASH_MAX_BITS;
1301
1302	ret = -ENOMEM;
1303	new_hash = alloc_ftrace_hash(bits);
1304	if (!new_hash)
1305		goto out;
 
 
1306
1307	size = 1 << src->size_bits;
1308	for (i = 0; i < size; i++) {
1309		hhd = &src->buckets[i];
1310		hlist_for_each_entry_safe(entry, tp, tn, hhd, hlist) {
1311			if (bits > 0)
1312				key = hash_long(entry->ip, bits);
1313			else
1314				key = 0;
1315			remove_hash_entry(src, entry);
1316			__add_hash_entry(new_hash, entry);
1317		}
1318	}
1319
1320	old_hash = *dst;
1321	rcu_assign_pointer(*dst, new_hash);
1322	free_ftrace_hash_rcu(old_hash);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1323
1324	ret = 0;
1325 out:
1326	/*
1327	 * Enable regardless of ret:
1328	 *  On success, we enable the new hash.
1329	 *  On failure, we re-enable the original hash.
1330	 */
1331	ftrace_hash_rec_enable(ops, enable);
1332
1333	return ret;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1334}
1335
1336/*
1337 * Test the hashes for this ops to see if we want to call
1338 * the ops->func or not.
1339 *
1340 * It's a match if the ip is in the ops->filter_hash or
1341 * the filter_hash does not exist or is empty,
1342 *  AND
1343 * the ip is not in the ops->notrace_hash.
1344 *
1345 * This needs to be called with preemption disabled as
1346 * the hashes are freed with call_rcu_sched().
1347 */
1348static int
1349ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
1350{
1351	struct ftrace_hash *filter_hash;
1352	struct ftrace_hash *notrace_hash;
1353	int ret;
1354
1355	filter_hash = rcu_dereference_raw(ops->filter_hash);
1356	notrace_hash = rcu_dereference_raw(ops->notrace_hash);
 
 
 
 
 
 
 
 
 
 
1357
1358	if ((ftrace_hash_empty(filter_hash) ||
1359	     ftrace_lookup_ip(filter_hash, ip)) &&
1360	    (ftrace_hash_empty(notrace_hash) ||
1361	     !ftrace_lookup_ip(notrace_hash, ip)))
1362		ret = 1;
1363	else
1364		ret = 0;
1365
1366	return ret;
1367}
1368
1369/*
1370 * This is a double for. Do not use 'break' to break out of the loop,
1371 * you must use a goto.
1372 */
1373#define do_for_each_ftrace_rec(pg, rec)					\
1374	for (pg = ftrace_pages_start; pg; pg = pg->next) {		\
1375		int _____i;						\
1376		for (_____i = 0; _____i < pg->index; _____i++) {	\
1377			rec = &pg->records[_____i];
1378
1379#define while_for_each_ftrace_rec()		\
1380		}				\
1381	}
1382
1383
1384static int ftrace_cmp_recs(const void *a, const void *b)
1385{
1386	const struct dyn_ftrace *key = a;
1387	const struct dyn_ftrace *rec = b;
1388
1389	if (key->flags < rec->ip)
1390		return -1;
1391	if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1392		return 1;
1393	return 0;
1394}
1395
1396static unsigned long ftrace_location_range(unsigned long start, unsigned long end)
 
 
 
 
 
 
 
 
 
 
 
 
1397{
1398	struct ftrace_page *pg;
1399	struct dyn_ftrace *rec;
1400	struct dyn_ftrace key;
1401
1402	key.ip = start;
1403	key.flags = end;	/* overload flags, as it is unsigned long */
1404
1405	for (pg = ftrace_pages_start; pg; pg = pg->next) {
1406		if (end < pg->records[0].ip ||
1407		    start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1408			continue;
1409		rec = bsearch(&key, pg->records, pg->index,
1410			      sizeof(struct dyn_ftrace),
1411			      ftrace_cmp_recs);
1412		if (rec)
1413			return rec->ip;
1414	}
1415
1416	return 0;
1417}
1418
1419/**
1420 * ftrace_location - return true if the ip giving is a traced location
1421 * @ip: the instruction pointer to check
1422 *
1423 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1424 * That is, the instruction that is either a NOP or call to
1425 * the function tracer. It checks the ftrace internal tables to
1426 * determine if the address belongs or not.
1427 */
1428unsigned long ftrace_location(unsigned long ip)
1429{
1430	return ftrace_location_range(ip, ip);
1431}
1432
1433/**
1434 * ftrace_text_reserved - return true if range contains an ftrace location
1435 * @start: start of range to search
1436 * @end: end of range to search (inclusive). @end points to the last byte to check.
1437 *
1438 * Returns 1 if @start and @end contains a ftrace location.
1439 * That is, the instruction that is either a NOP or call to
1440 * the function tracer. It checks the ftrace internal tables to
1441 * determine if the address belongs or not.
1442 */
1443int ftrace_text_reserved(void *start, void *end)
1444{
1445	unsigned long ret;
1446
1447	ret = ftrace_location_range((unsigned long)start,
1448				    (unsigned long)end);
1449
1450	return (int)!!ret;
1451}
1452
1453static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1454				     int filter_hash,
1455				     bool inc)
1456{
1457	struct ftrace_hash *hash;
1458	struct ftrace_hash *other_hash;
1459	struct ftrace_page *pg;
1460	struct dyn_ftrace *rec;
 
1461	int count = 0;
1462	int all = 0;
1463
1464	/* Only update if the ops has been registered */
1465	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1466		return;
1467
1468	/*
1469	 * In the filter_hash case:
1470	 *   If the count is zero, we update all records.
1471	 *   Otherwise we just update the items in the hash.
1472	 *
1473	 * In the notrace_hash case:
1474	 *   We enable the update in the hash.
1475	 *   As disabling notrace means enabling the tracing,
1476	 *   and enabling notrace means disabling, the inc variable
1477	 *   gets inversed.
1478	 */
1479	if (filter_hash) {
1480		hash = ops->filter_hash;
1481		other_hash = ops->notrace_hash;
1482		if (ftrace_hash_empty(hash))
1483			all = 1;
1484	} else {
1485		inc = !inc;
1486		hash = ops->notrace_hash;
1487		other_hash = ops->filter_hash;
1488		/*
1489		 * If the notrace hash has no items,
1490		 * then there's nothing to do.
1491		 */
1492		if (ftrace_hash_empty(hash))
1493			return;
1494	}
1495
1496	do_for_each_ftrace_rec(pg, rec) {
1497		int in_other_hash = 0;
1498		int in_hash = 0;
1499		int match = 0;
1500
 
 
 
1501		if (all) {
1502			/*
1503			 * Only the filter_hash affects all records.
1504			 * Update if the record is not in the notrace hash.
1505			 */
1506			if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1507				match = 1;
1508		} else {
1509			in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1510			in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1511
1512			/*
 
 
1513			 *
 
 
 
 
 
1514			 */
1515			if (filter_hash && in_hash && !in_other_hash)
1516				match = 1;
1517			else if (!filter_hash && in_hash &&
1518				 (in_other_hash || ftrace_hash_empty(other_hash)))
1519				match = 1;
1520		}
1521		if (!match)
1522			continue;
1523
1524		if (inc) {
1525			rec->flags++;
1526			if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX))
1527				return;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1528		} else {
1529			if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))
1530				return;
1531			rec->flags--;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1532		}
1533		count++;
 
 
 
 
1534		/* Shortcut, if we handled all records, we are done. */
1535		if (!all && count == hash->count)
1536			return;
1537	} while_for_each_ftrace_rec();
 
 
1538}
1539
1540static void ftrace_hash_rec_disable(struct ftrace_ops *ops,
1541				    int filter_hash)
1542{
1543	__ftrace_hash_rec_update(ops, filter_hash, 0);
1544}
1545
1546static void ftrace_hash_rec_enable(struct ftrace_ops *ops,
1547				   int filter_hash)
1548{
1549	__ftrace_hash_rec_update(ops, filter_hash, 1);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1550}
1551
1552static void print_ip_ins(const char *fmt, unsigned char *p)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1553{
1554	int i;
1555
1556	printk(KERN_CONT "%s", fmt);
1557
1558	for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1559		printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1560}
1561
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1562/**
1563 * ftrace_bug - report and shutdown function tracer
1564 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1565 * @ip: The address that failed
1566 *
1567 * The arch code that enables or disables the function tracing
1568 * can call ftrace_bug() when it has detected a problem in
1569 * modifying the code. @failed should be one of either:
1570 * EFAULT - if the problem happens on reading the @ip address
1571 * EINVAL - if what is read at @ip is not what was expected
1572 * EPERM - if the problem happens on writting to the @ip address
1573 */
1574void ftrace_bug(int failed, unsigned long ip)
1575{
 
 
1576	switch (failed) {
1577	case -EFAULT:
1578		FTRACE_WARN_ON_ONCE(1);
1579		pr_info("ftrace faulted on modifying ");
1580		print_ip_sym(ip);
1581		break;
1582	case -EINVAL:
1583		FTRACE_WARN_ON_ONCE(1);
1584		pr_info("ftrace failed to modify ");
1585		print_ip_sym(ip);
1586		print_ip_ins(" actual: ", (unsigned char *)ip);
1587		printk(KERN_CONT "\n");
 
 
 
 
1588		break;
1589	case -EPERM:
1590		FTRACE_WARN_ON_ONCE(1);
1591		pr_info("ftrace faulted on writing ");
1592		print_ip_sym(ip);
1593		break;
1594	default:
1595		FTRACE_WARN_ON_ONCE(1);
1596		pr_info("ftrace faulted on unknown error ");
1597		print_ip_sym(ip);
1598	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1599}
1600
1601static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
1602{
1603	unsigned long flag = 0UL;
1604
 
 
 
 
 
1605	/*
1606	 * If we are updating calls:
1607	 *
1608	 *   If the record has a ref count, then we need to enable it
1609	 *   because someone is using it.
1610	 *
1611	 *   Otherwise we make sure its disabled.
1612	 *
1613	 * If we are disabling calls, then disable all records that
1614	 * are enabled.
1615	 */
1616	if (enable && (rec->flags & ~FTRACE_FL_MASK))
1617		flag = FTRACE_FL_ENABLED;
1618
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1619	/* If the state of this record hasn't changed, then do nothing */
1620	if ((rec->flags & FTRACE_FL_ENABLED) == flag)
1621		return FTRACE_UPDATE_IGNORE;
1622
1623	if (flag) {
1624		if (update)
 
 
 
1625			rec->flags |= FTRACE_FL_ENABLED;
1626		return FTRACE_UPDATE_MAKE_CALL;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1627	}
1628
1629	if (update)
1630		rec->flags &= ~FTRACE_FL_ENABLED;
 
 
 
 
 
 
 
 
 
 
1631
 
1632	return FTRACE_UPDATE_MAKE_NOP;
1633}
1634
1635/**
1636 * ftrace_update_record, set a record that now is tracing or not
1637 * @rec: the record to update
1638 * @enable: set to 1 if the record is tracing, zero to force disable
1639 *
1640 * The records that represent all functions that can be traced need
1641 * to be updated when tracing has been enabled.
1642 */
1643int ftrace_update_record(struct dyn_ftrace *rec, int enable)
1644{
1645	return ftrace_check_record(rec, enable, 1);
1646}
1647
1648/**
1649 * ftrace_test_record, check if the record has been enabled or not
1650 * @rec: the record to test
1651 * @enable: set to 1 to check if enabled, 0 if it is disabled
1652 *
1653 * The arch code may need to test if a record is already set to
1654 * tracing to determine how to modify the function code that it
1655 * represents.
1656 */
1657int ftrace_test_record(struct dyn_ftrace *rec, int enable)
1658{
1659	return ftrace_check_record(rec, enable, 0);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1660}
1661
1662static int
1663__ftrace_replace_code(struct dyn_ftrace *rec, int enable)
1664{
 
1665	unsigned long ftrace_addr;
1666	int ret;
1667
1668	ftrace_addr = (unsigned long)FTRACE_ADDR;
 
 
 
1669
1670	ret = ftrace_update_record(rec, enable);
1671
 
 
1672	switch (ret) {
1673	case FTRACE_UPDATE_IGNORE:
1674		return 0;
1675
1676	case FTRACE_UPDATE_MAKE_CALL:
 
1677		return ftrace_make_call(rec, ftrace_addr);
1678
1679	case FTRACE_UPDATE_MAKE_NOP:
1680		return ftrace_make_nop(NULL, rec, ftrace_addr);
 
 
 
 
 
1681	}
1682
1683	return -1; /* unknow ftrace bug */
1684}
1685
1686void __weak ftrace_replace_code(int enable)
1687{
1688	struct dyn_ftrace *rec;
1689	struct ftrace_page *pg;
 
 
1690	int failed;
1691
1692	if (unlikely(ftrace_disabled))
1693		return;
1694
1695	do_for_each_ftrace_rec(pg, rec) {
 
 
 
 
1696		failed = __ftrace_replace_code(rec, enable);
1697		if (failed) {
1698			ftrace_bug(failed, rec->ip);
1699			/* Stop processing */
1700			return;
1701		}
 
 
1702	} while_for_each_ftrace_rec();
1703}
1704
1705struct ftrace_rec_iter {
1706	struct ftrace_page	*pg;
1707	int			index;
1708};
1709
1710/**
1711 * ftrace_rec_iter_start, start up iterating over traced functions
1712 *
1713 * Returns an iterator handle that is used to iterate over all
1714 * the records that represent address locations where functions
1715 * are traced.
1716 *
1717 * May return NULL if no records are available.
1718 */
1719struct ftrace_rec_iter *ftrace_rec_iter_start(void)
1720{
1721	/*
1722	 * We only use a single iterator.
1723	 * Protected by the ftrace_lock mutex.
1724	 */
1725	static struct ftrace_rec_iter ftrace_rec_iter;
1726	struct ftrace_rec_iter *iter = &ftrace_rec_iter;
1727
1728	iter->pg = ftrace_pages_start;
1729	iter->index = 0;
1730
1731	/* Could have empty pages */
1732	while (iter->pg && !iter->pg->index)
1733		iter->pg = iter->pg->next;
1734
1735	if (!iter->pg)
1736		return NULL;
1737
1738	return iter;
1739}
1740
1741/**
1742 * ftrace_rec_iter_next, get the next record to process.
1743 * @iter: The handle to the iterator.
1744 *
1745 * Returns the next iterator after the given iterator @iter.
1746 */
1747struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
1748{
1749	iter->index++;
1750
1751	if (iter->index >= iter->pg->index) {
1752		iter->pg = iter->pg->next;
1753		iter->index = 0;
1754
1755		/* Could have empty pages */
1756		while (iter->pg && !iter->pg->index)
1757			iter->pg = iter->pg->next;
1758	}
1759
1760	if (!iter->pg)
1761		return NULL;
1762
1763	return iter;
1764}
1765
1766/**
1767 * ftrace_rec_iter_record, get the record at the iterator location
1768 * @iter: The current iterator location
1769 *
1770 * Returns the record that the current @iter is at.
1771 */
1772struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
1773{
1774	return &iter->pg->records[iter->index];
1775}
1776
1777static int
1778ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
1779{
1780	unsigned long ip;
1781	int ret;
1782
1783	ip = rec->ip;
1784
1785	if (unlikely(ftrace_disabled))
1786		return 0;
1787
1788	ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
1789	if (ret) {
1790		ftrace_bug(ret, ip);
 
1791		return 0;
1792	}
1793	return 1;
1794}
1795
1796/*
1797 * archs can override this function if they must do something
1798 * before the modifying code is performed.
1799 */
1800int __weak ftrace_arch_code_modify_prepare(void)
1801{
1802	return 0;
1803}
1804
1805/*
1806 * archs can override this function if they must do something
1807 * after the modifying code is performed.
1808 */
1809int __weak ftrace_arch_code_modify_post_process(void)
1810{
1811	return 0;
1812}
1813
1814void ftrace_modify_all_code(int command)
1815{
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1816	if (command & FTRACE_UPDATE_CALLS)
1817		ftrace_replace_code(1);
1818	else if (command & FTRACE_DISABLE_CALLS)
1819		ftrace_replace_code(0);
1820
1821	if (command & FTRACE_UPDATE_TRACE_FUNC)
1822		ftrace_update_ftrace_func(ftrace_trace_function);
 
 
 
 
 
 
 
 
1823
1824	if (command & FTRACE_START_FUNC_RET)
1825		ftrace_enable_ftrace_graph_caller();
1826	else if (command & FTRACE_STOP_FUNC_RET)
1827		ftrace_disable_ftrace_graph_caller();
 
1828}
1829
1830static int __ftrace_modify_code(void *data)
1831{
1832	int *command = data;
1833
1834	ftrace_modify_all_code(*command);
1835
1836	return 0;
1837}
1838
1839/**
1840 * ftrace_run_stop_machine, go back to the stop machine method
1841 * @command: The command to tell ftrace what to do
1842 *
1843 * If an arch needs to fall back to the stop machine method, the
1844 * it can call this function.
1845 */
1846void ftrace_run_stop_machine(int command)
1847{
1848	stop_machine(__ftrace_modify_code, &command, NULL);
1849}
1850
1851/**
1852 * arch_ftrace_update_code, modify the code to trace or not trace
1853 * @command: The command that needs to be done
1854 *
1855 * Archs can override this function if it does not need to
1856 * run stop_machine() to modify code.
1857 */
1858void __weak arch_ftrace_update_code(int command)
1859{
1860	ftrace_run_stop_machine(command);
1861}
1862
1863static void ftrace_run_update_code(int command)
1864{
1865	int ret;
1866
1867	ret = ftrace_arch_code_modify_prepare();
1868	FTRACE_WARN_ON(ret);
1869	if (ret)
1870		return;
1871	/*
1872	 * Do not call function tracer while we update the code.
1873	 * We are in stop machine.
1874	 */
1875	function_trace_stop++;
1876
1877	/*
1878	 * By default we use stop_machine() to modify the code.
1879	 * But archs can do what ever they want as long as it
1880	 * is safe. The stop_machine() is the safest, but also
1881	 * produces the most overhead.
1882	 */
1883	arch_ftrace_update_code(command);
1884
1885#ifndef CONFIG_HAVE_FUNCTION_TRACE_MCOUNT_TEST
1886	/*
1887	 * For archs that call ftrace_test_stop_func(), we must
1888	 * wait till after we update all the function callers
1889	 * before we update the callback. This keeps different
1890	 * ops that record different functions from corrupting
1891	 * each other.
1892	 */
1893	__ftrace_trace_function = __ftrace_trace_function_delay;
1894#endif
1895	function_trace_stop--;
1896
1897	ret = ftrace_arch_code_modify_post_process();
1898	FTRACE_WARN_ON(ret);
1899}
1900
 
 
 
 
 
 
 
 
 
 
 
 
1901static ftrace_func_t saved_ftrace_func;
1902static int ftrace_start_up;
1903static int global_start_up;
 
 
 
1904
1905static void ftrace_startup_enable(int command)
1906{
1907	if (saved_ftrace_func != ftrace_trace_function) {
1908		saved_ftrace_func = ftrace_trace_function;
1909		command |= FTRACE_UPDATE_TRACE_FUNC;
1910	}
1911
1912	if (!command || !ftrace_enabled)
1913		return;
1914
1915	ftrace_run_update_code(command);
1916}
1917
1918static int ftrace_startup(struct ftrace_ops *ops, int command)
 
 
 
 
 
 
 
1919{
1920	bool hash_enable = true;
1921
1922	if (unlikely(ftrace_disabled))
1923		return -ENODEV;
1924
 
 
 
 
1925	ftrace_start_up++;
1926	command |= FTRACE_UPDATE_CALLS;
1927
1928	/* ops marked global share the filter hashes */
1929	if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1930		ops = &global_ops;
1931		/* Don't update hash if global is already set */
1932		if (global_start_up)
1933			hash_enable = false;
1934		global_start_up++;
 
 
 
 
 
 
 
 
 
 
1935	}
1936
1937	ops->flags |= FTRACE_OPS_FL_ENABLED;
1938	if (hash_enable)
1939		ftrace_hash_rec_enable(ops, 1);
1940
1941	ftrace_startup_enable(command);
1942
 
 
1943	return 0;
1944}
1945
1946static void ftrace_shutdown(struct ftrace_ops *ops, int command)
1947{
1948	bool hash_disable = true;
1949
1950	if (unlikely(ftrace_disabled))
1951		return;
 
 
 
 
1952
1953	ftrace_start_up--;
1954	/*
1955	 * Just warn in case of unbalance, no need to kill ftrace, it's not
1956	 * critical but the ftrace_call callers may be never nopped again after
1957	 * further ftrace uses.
1958	 */
1959	WARN_ON_ONCE(ftrace_start_up < 0);
1960
1961	if (ops->flags & FTRACE_OPS_FL_GLOBAL) {
1962		ops = &global_ops;
1963		global_start_up--;
1964		WARN_ON_ONCE(global_start_up < 0);
1965		/* Don't update hash if global still has users */
1966		if (global_start_up) {
1967			WARN_ON_ONCE(!ftrace_start_up);
1968			hash_disable = false;
1969		}
1970	}
1971
1972	if (hash_disable)
1973		ftrace_hash_rec_disable(ops, 1);
1974
1975	if (ops != &global_ops || !global_start_up)
1976		ops->flags &= ~FTRACE_OPS_FL_ENABLED;
1977
1978	command |= FTRACE_UPDATE_CALLS;
1979
1980	if (saved_ftrace_func != ftrace_trace_function) {
1981		saved_ftrace_func = ftrace_trace_function;
1982		command |= FTRACE_UPDATE_TRACE_FUNC;
1983	}
1984
1985	if (!command || !ftrace_enabled)
1986		return;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1987
1988	ftrace_run_update_code(command);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1989}
1990
1991static void ftrace_startup_sysctl(void)
1992{
 
 
1993	if (unlikely(ftrace_disabled))
1994		return;
1995
1996	/* Force update next time */
1997	saved_ftrace_func = NULL;
1998	/* ftrace_start_up is true if we want ftrace running */
1999	if (ftrace_start_up)
2000		ftrace_run_update_code(FTRACE_UPDATE_CALLS);
 
 
 
 
2001}
2002
2003static void ftrace_shutdown_sysctl(void)
2004{
 
 
2005	if (unlikely(ftrace_disabled))
2006		return;
2007
2008	/* ftrace_start_up is true if ftrace is running */
2009	if (ftrace_start_up)
2010		ftrace_run_update_code(FTRACE_DISABLE_CALLS);
 
 
 
 
2011}
2012
2013static cycle_t		ftrace_update_time;
2014static unsigned long	ftrace_update_cnt;
2015unsigned long		ftrace_update_tot_cnt;
2016
2017static int ops_traces_mod(struct ftrace_ops *ops)
2018{
2019	struct ftrace_hash *hash;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2020
2021	hash = ops->filter_hash;
2022	return ftrace_hash_empty(hash);
 
 
 
 
 
 
 
 
 
 
 
 
2023}
2024
2025static int ftrace_update_code(struct module *mod)
2026{
2027	struct ftrace_page *pg;
2028	struct dyn_ftrace *p;
2029	cycle_t start, stop;
2030	unsigned long ref = 0;
 
2031	int i;
2032
 
 
2033	/*
2034	 * When adding a module, we need to check if tracers are
2035	 * currently enabled and if they are set to trace all functions.
2036	 * If they are, we need to enable the module functions as well
2037	 * as update the reference counts for those function records.
 
 
 
 
 
2038	 */
2039	if (mod) {
2040		struct ftrace_ops *ops;
2041
2042		for (ops = ftrace_ops_list;
2043		     ops != &ftrace_list_end; ops = ops->next) {
2044			if (ops->flags & FTRACE_OPS_FL_ENABLED &&
2045			    ops_traces_mod(ops))
2046				ref++;
2047		}
2048	}
2049
2050	start = ftrace_now(raw_smp_processor_id());
2051	ftrace_update_cnt = 0;
2052
2053	for (pg = ftrace_new_pgs; pg; pg = pg->next) {
2054
2055		for (i = 0; i < pg->index; i++) {
 
2056			/* If something went wrong, bail without enabling anything */
2057			if (unlikely(ftrace_disabled))
2058				return -1;
2059
2060			p = &pg->records[i];
2061			p->flags = ref;
2062
2063			/*
2064			 * Do the initial record conversion from mcount jump
2065			 * to the NOP instructions.
2066			 */
2067			if (!ftrace_code_disable(mod, p))
 
2068				break;
2069
2070			ftrace_update_cnt++;
2071
2072			/*
2073			 * If the tracing is enabled, go ahead and enable the record.
2074			 *
2075			 * The reason not to enable the record immediatelly is the
2076			 * inherent check of ftrace_make_nop/ftrace_make_call for
2077			 * correct previous instructions.  Making first the NOP
2078			 * conversion puts the module to the correct state, thus
2079			 * passing the ftrace_make_call check.
2080			 */
2081			if (ftrace_start_up && ref) {
2082				int failed = __ftrace_replace_code(p, 1);
2083				if (failed)
2084					ftrace_bug(failed, p->ip);
2085			}
2086		}
2087	}
2088
2089	ftrace_new_pgs = NULL;
2090
2091	stop = ftrace_now(raw_smp_processor_id());
2092	ftrace_update_time = stop - start;
2093	ftrace_update_tot_cnt += ftrace_update_cnt;
2094
2095	return 0;
2096}
2097
2098static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2099{
2100	int order;
2101	int cnt;
2102
2103	if (WARN_ON(!count))
2104		return -EINVAL;
2105
2106	order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2107
2108	/*
2109	 * We want to fill as much as possible. No more than a page
2110	 * may be empty.
2111	 */
2112	while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2113		order--;
2114
2115 again:
2116	pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2117
2118	if (!pg->records) {
2119		/* if we can't allocate this size, try something smaller */
2120		if (!order)
2121			return -ENOMEM;
2122		order >>= 1;
2123		goto again;
2124	}
2125
2126	cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2127	pg->size = cnt;
2128
2129	if (cnt > count)
2130		cnt = count;
2131
2132	return cnt;
2133}
2134
2135static struct ftrace_page *
2136ftrace_allocate_pages(unsigned long num_to_init)
2137{
2138	struct ftrace_page *start_pg;
2139	struct ftrace_page *pg;
2140	int order;
2141	int cnt;
2142
2143	if (!num_to_init)
2144		return 0;
2145
2146	start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
2147	if (!pg)
2148		return NULL;
2149
2150	/*
2151	 * Try to allocate as much as possible in one continues
2152	 * location that fills in all of the space. We want to
2153	 * waste as little space as possible.
2154	 */
2155	for (;;) {
2156		cnt = ftrace_allocate_records(pg, num_to_init);
2157		if (cnt < 0)
2158			goto free_pages;
2159
2160		num_to_init -= cnt;
2161		if (!num_to_init)
2162			break;
2163
2164		pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
2165		if (!pg->next)
2166			goto free_pages;
2167
2168		pg = pg->next;
2169	}
2170
2171	return start_pg;
2172
2173 free_pages:
2174	while (start_pg) {
 
2175		order = get_count_order(pg->size / ENTRIES_PER_PAGE);
2176		free_pages((unsigned long)pg->records, order);
2177		start_pg = pg->next;
2178		kfree(pg);
2179		pg = start_pg;
2180	}
2181	pr_info("ftrace: FAILED to allocate memory for functions\n");
2182	return NULL;
2183}
2184
2185static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
2186{
2187	int cnt;
2188
2189	if (!num_to_init) {
2190		pr_info("ftrace: No functions to be traced?\n");
2191		return -1;
2192	}
2193
2194	cnt = num_to_init / ENTRIES_PER_PAGE;
2195	pr_info("ftrace: allocating %ld entries in %d pages\n",
2196		num_to_init, cnt + 1);
2197
2198	return 0;
2199}
2200
2201#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
2202
2203struct ftrace_iterator {
2204	loff_t				pos;
2205	loff_t				func_pos;
 
2206	struct ftrace_page		*pg;
2207	struct dyn_ftrace		*func;
2208	struct ftrace_func_probe	*probe;
 
2209	struct trace_parser		parser;
2210	struct ftrace_hash		*hash;
2211	struct ftrace_ops		*ops;
2212	int				hidx;
 
 
2213	int				idx;
2214	unsigned			flags;
2215};
2216
2217static void *
2218t_hash_next(struct seq_file *m, loff_t *pos)
2219{
2220	struct ftrace_iterator *iter = m->private;
 
 
 
 
2221	struct hlist_node *hnd = NULL;
2222	struct hlist_head *hhd;
 
2223
2224	(*pos)++;
2225	iter->pos = *pos;
2226
2227	if (iter->probe)
2228		hnd = &iter->probe->node;
2229 retry:
2230	if (iter->hidx >= FTRACE_FUNC_HASHSIZE)
 
2231		return NULL;
2232
2233	hhd = &ftrace_func_hash[iter->hidx];
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2234
2235	if (hlist_empty(hhd)) {
2236		iter->hidx++;
2237		hnd = NULL;
2238		goto retry;
2239	}
2240
2241	if (!hnd)
2242		hnd = hhd->first;
2243	else {
2244		hnd = hnd->next;
2245		if (!hnd) {
2246			iter->hidx++;
2247			goto retry;
2248		}
2249	}
2250
2251	if (WARN_ON_ONCE(!hnd))
2252		return NULL;
2253
2254	iter->probe = hlist_entry(hnd, struct ftrace_func_probe, node);
2255
2256	return iter;
2257}
2258
2259static void *t_hash_start(struct seq_file *m, loff_t *pos)
2260{
2261	struct ftrace_iterator *iter = m->private;
2262	void *p = NULL;
2263	loff_t l;
2264
2265	if (!(iter->flags & FTRACE_ITER_DO_HASH))
2266		return NULL;
2267
2268	if (iter->func_pos > *pos)
2269		return NULL;
2270
2271	iter->hidx = 0;
2272	for (l = 0; l <= (*pos - iter->func_pos); ) {
2273		p = t_hash_next(m, &l);
 
 
2274		if (!p)
2275			break;
2276	}
2277	if (!p)
2278		return NULL;
2279
2280	/* Only set this if we have an item */
2281	iter->flags |= FTRACE_ITER_HASH;
2282
2283	return iter;
2284}
2285
2286static int
2287t_hash_show(struct seq_file *m, struct ftrace_iterator *iter)
2288{
2289	struct ftrace_func_probe *rec;
 
 
 
 
 
2290
2291	rec = iter->probe;
2292	if (WARN_ON_ONCE(!rec))
2293		return -EIO;
2294
2295	if (rec->ops->print)
2296		return rec->ops->print(m, rec->ip, rec->ops, rec->data);
2297
2298	seq_printf(m, "%ps:%ps", (void *)rec->ip, (void *)rec->ops->func);
 
2299
2300	if (rec->data)
2301		seq_printf(m, ":%p", rec->data);
2302	seq_putc(m, '\n');
2303
2304	return 0;
2305}
2306
2307static void *
2308t_next(struct seq_file *m, void *v, loff_t *pos)
2309{
2310	struct ftrace_iterator *iter = m->private;
2311	struct ftrace_ops *ops = iter->ops;
2312	struct dyn_ftrace *rec = NULL;
2313
2314	if (unlikely(ftrace_disabled))
 
 
 
 
 
 
 
2315		return NULL;
 
2316
2317	if (iter->flags & FTRACE_ITER_HASH)
2318		return t_hash_next(m, pos);
2319
2320	(*pos)++;
2321	iter->pos = iter->func_pos = *pos;
 
 
 
 
 
 
 
 
 
 
 
2322
2323	if (iter->flags & FTRACE_ITER_PRINTALL)
2324		return t_hash_start(m, pos);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2325
2326 retry:
2327	if (iter->idx >= iter->pg->index) {
2328		if (iter->pg->next) {
2329			iter->pg = iter->pg->next;
2330			iter->idx = 0;
2331			goto retry;
2332		}
2333	} else {
2334		rec = &iter->pg->records[iter->idx++];
2335		if (((iter->flags & FTRACE_ITER_FILTER) &&
2336		     !(ftrace_lookup_ip(ops->filter_hash, rec->ip))) ||
2337
2338		    ((iter->flags & FTRACE_ITER_NOTRACE) &&
2339		     !ftrace_lookup_ip(ops->notrace_hash, rec->ip)) ||
2340
2341		    ((iter->flags & FTRACE_ITER_ENABLED) &&
2342		     !(rec->flags & ~FTRACE_FL_MASK))) {
2343
2344			rec = NULL;
2345			goto retry;
2346		}
2347	}
2348
2349	if (!rec)
2350		return t_hash_start(m, pos);
2351
 
2352	iter->func = rec;
2353
2354	return iter;
2355}
2356
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2357static void reset_iter_read(struct ftrace_iterator *iter)
2358{
2359	iter->pos = 0;
2360	iter->func_pos = 0;
2361	iter->flags &= ~(FTRACE_ITER_PRINTALL & FTRACE_ITER_HASH);
2362}
2363
2364static void *t_start(struct seq_file *m, loff_t *pos)
2365{
2366	struct ftrace_iterator *iter = m->private;
2367	struct ftrace_ops *ops = iter->ops;
2368	void *p = NULL;
2369	loff_t l;
2370
2371	mutex_lock(&ftrace_lock);
2372
2373	if (unlikely(ftrace_disabled))
2374		return NULL;
2375
2376	/*
2377	 * If an lseek was done, then reset and start from beginning.
2378	 */
2379	if (*pos < iter->pos)
2380		reset_iter_read(iter);
2381
2382	/*
2383	 * For set_ftrace_filter reading, if we have the filter
2384	 * off, we can short cut and just print out that all
2385	 * functions are enabled.
2386	 */
2387	if (iter->flags & FTRACE_ITER_FILTER &&
2388	    ftrace_hash_empty(ops->filter_hash)) {
 
2389		if (*pos > 0)
2390			return t_hash_start(m, pos);
2391		iter->flags |= FTRACE_ITER_PRINTALL;
2392		/* reset in case of seek/pread */
2393		iter->flags &= ~FTRACE_ITER_HASH;
2394		return iter;
2395	}
2396
2397	if (iter->flags & FTRACE_ITER_HASH)
2398		return t_hash_start(m, pos);
2399
2400	/*
2401	 * Unfortunately, we need to restart at ftrace_pages_start
2402	 * every time we let go of the ftrace_mutex. This is because
2403	 * those pointers can change without the lock.
2404	 */
2405	iter->pg = ftrace_pages_start;
2406	iter->idx = 0;
2407	for (l = 0; l <= *pos; ) {
2408		p = t_next(m, p, &l);
2409		if (!p)
2410			break;
2411	}
2412
2413	if (!p)
2414		return t_hash_start(m, pos);
2415
2416	return iter;
2417}
2418
2419static void t_stop(struct seq_file *m, void *p)
2420{
2421	mutex_unlock(&ftrace_lock);
2422}
2423
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2424static int t_show(struct seq_file *m, void *v)
2425{
2426	struct ftrace_iterator *iter = m->private;
2427	struct dyn_ftrace *rec;
2428
2429	if (iter->flags & FTRACE_ITER_HASH)
2430		return t_hash_show(m, iter);
 
 
 
2431
2432	if (iter->flags & FTRACE_ITER_PRINTALL) {
2433		seq_printf(m, "#### all functions enabled ####\n");
 
 
 
2434		return 0;
2435	}
2436
2437	rec = iter->func;
2438
2439	if (!rec)
2440		return 0;
2441
2442	seq_printf(m, "%ps", (void *)rec->ip);
2443	if (iter->flags & FTRACE_ITER_ENABLED)
2444		seq_printf(m, " (%ld)",
2445			   rec->flags & ~FTRACE_FL_MASK);
2446	seq_printf(m, "\n");
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2447
2448	return 0;
2449}
2450
2451static const struct seq_operations show_ftrace_seq_ops = {
2452	.start = t_start,
2453	.next = t_next,
2454	.stop = t_stop,
2455	.show = t_show,
2456};
2457
2458static int
2459ftrace_avail_open(struct inode *inode, struct file *file)
2460{
2461	struct ftrace_iterator *iter;
 
 
 
 
 
2462
2463	if (unlikely(ftrace_disabled))
2464		return -ENODEV;
2465
2466	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2467	if (iter) {
2468		iter->pg = ftrace_pages_start;
2469		iter->ops = &global_ops;
2470	}
 
2471
2472	return iter ? 0 : -ENOMEM;
2473}
2474
2475static int
2476ftrace_enabled_open(struct inode *inode, struct file *file)
2477{
2478	struct ftrace_iterator *iter;
2479
2480	if (unlikely(ftrace_disabled))
2481		return -ENODEV;
 
 
 
 
 
 
2482
2483	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
2484	if (iter) {
2485		iter->pg = ftrace_pages_start;
2486		iter->flags = FTRACE_ITER_ENABLED;
2487		iter->ops = &global_ops;
2488	}
2489
2490	return iter ? 0 : -ENOMEM;
2491}
 
2492
2493static void ftrace_filter_reset(struct ftrace_hash *hash)
2494{
2495	mutex_lock(&ftrace_lock);
2496	ftrace_hash_clear(hash);
2497	mutex_unlock(&ftrace_lock);
2498}
2499
2500/**
2501 * ftrace_regex_open - initialize function tracer filter files
2502 * @ops: The ftrace_ops that hold the hash filters
2503 * @flag: The type of filter to process
2504 * @inode: The inode, usually passed in to your open routine
2505 * @file: The file, usually passed in to your open routine
2506 *
2507 * ftrace_regex_open() initializes the filter files for the
2508 * @ops. Depending on @flag it may process the filter hash or
2509 * the notrace hash of @ops. With this called from the open
2510 * routine, you can use ftrace_filter_write() for the write
2511 * routine if @flag has FTRACE_ITER_FILTER set, or
2512 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
2513 * ftrace_regex_lseek() should be used as the lseek routine, and
2514 * release must call ftrace_regex_release().
2515 */
2516int
2517ftrace_regex_open(struct ftrace_ops *ops, int flag,
2518		  struct inode *inode, struct file *file)
2519{
2520	struct ftrace_iterator *iter;
2521	struct ftrace_hash *hash;
2522	int ret = 0;
 
 
 
 
2523
2524	if (unlikely(ftrace_disabled))
2525		return -ENODEV;
2526
 
 
 
2527	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
2528	if (!iter)
2529		return -ENOMEM;
2530
2531	if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX)) {
2532		kfree(iter);
2533		return -ENOMEM;
2534	}
2535
2536	if (flag & FTRACE_ITER_NOTRACE)
2537		hash = ops->notrace_hash;
2538	else
2539		hash = ops->filter_hash;
2540
2541	iter->ops = ops;
2542	iter->flags = flag;
 
 
 
 
 
 
 
 
 
 
 
 
 
2543
2544	if (file->f_mode & FMODE_WRITE) {
2545		mutex_lock(&ftrace_lock);
2546		iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash);
2547		mutex_unlock(&ftrace_lock);
 
 
 
 
 
2548
2549		if (!iter->hash) {
2550			trace_parser_put(&iter->parser);
2551			kfree(iter);
2552			return -ENOMEM;
2553		}
2554	}
2555
2556	mutex_lock(&ftrace_regex_lock);
2557
2558	if ((file->f_mode & FMODE_WRITE) &&
2559	    (file->f_flags & O_TRUNC))
2560		ftrace_filter_reset(iter->hash);
2561
2562	if (file->f_mode & FMODE_READ) {
2563		iter->pg = ftrace_pages_start;
2564
2565		ret = seq_open(file, &show_ftrace_seq_ops);
2566		if (!ret) {
2567			struct seq_file *m = file->private_data;
2568			m->private = iter;
2569		} else {
2570			/* Failed */
2571			free_ftrace_hash(iter->hash);
2572			trace_parser_put(&iter->parser);
2573			kfree(iter);
2574		}
2575	} else
2576		file->private_data = iter;
2577	mutex_unlock(&ftrace_regex_lock);
 
 
 
 
 
 
 
 
 
2578
2579	return ret;
2580}
2581
2582static int
2583ftrace_filter_open(struct inode *inode, struct file *file)
2584{
2585	return ftrace_regex_open(&global_ops,
2586			FTRACE_ITER_FILTER | FTRACE_ITER_DO_HASH,
 
 
 
2587			inode, file);
2588}
2589
2590static int
2591ftrace_notrace_open(struct inode *inode, struct file *file)
2592{
2593	return ftrace_regex_open(&global_ops, FTRACE_ITER_NOTRACE,
 
 
 
2594				 inode, file);
2595}
2596
2597loff_t
2598ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
2599{
2600	loff_t ret;
2601
2602	if (file->f_mode & FMODE_READ)
2603		ret = seq_lseek(file, offset, origin);
2604	else
2605		file->f_pos = ret = 1;
2606
2607	return ret;
 
 
 
 
 
 
 
2608}
2609
2610static int ftrace_match(char *str, char *regex, int len, int type)
2611{
2612	int matched = 0;
2613	int slen;
2614
2615	switch (type) {
 
 
2616	case MATCH_FULL:
2617		if (strcmp(str, regex) == 0)
2618			matched = 1;
2619		break;
2620	case MATCH_FRONT_ONLY:
2621		if (strncmp(str, regex, len) == 0)
2622			matched = 1;
2623		break;
2624	case MATCH_MIDDLE_ONLY:
2625		if (strstr(str, regex))
2626			matched = 1;
2627		break;
2628	case MATCH_END_ONLY:
2629		slen = strlen(str);
2630		if (slen >= len && memcmp(str + slen - len, regex, len) == 0)
 
 
 
 
 
2631			matched = 1;
2632		break;
2633	}
2634
2635	return matched;
2636}
2637
2638static int
2639enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int not)
2640{
2641	struct ftrace_func_entry *entry;
2642	int ret = 0;
2643
2644	entry = ftrace_lookup_ip(hash, rec->ip);
2645	if (not) {
2646		/* Do nothing if it doesn't exist */
2647		if (!entry)
2648			return 0;
2649
2650		free_hash_entry(hash, entry);
2651	} else {
2652		/* Do nothing if it exists */
2653		if (entry)
2654			return 0;
2655
2656		ret = add_hash_entry(hash, rec->ip);
2657	}
2658	return ret;
2659}
2660
2661static int
2662ftrace_match_record(struct dyn_ftrace *rec, char *mod,
2663		    char *regex, int len, int type)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2664{
2665	char str[KSYM_SYMBOL_LEN];
2666	char *modname;
2667
2668	kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
2669
2670	if (mod) {
2671		/* module lookup requires matching the module */
2672		if (!modname || strcmp(modname, mod))
 
 
 
 
 
2673			return 0;
 
2674
 
 
 
 
 
 
 
 
 
 
2675		/* blank search means to match all funcs in the mod */
2676		if (!len)
2677			return 1;
2678	}
2679
2680	return ftrace_match(str, regex, len, type);
2681}
2682
2683static int
2684match_records(struct ftrace_hash *hash, char *buff,
2685	      int len, char *mod, int not)
2686{
2687	unsigned search_len = 0;
2688	struct ftrace_page *pg;
2689	struct dyn_ftrace *rec;
2690	int type = MATCH_FULL;
2691	char *search = buff;
 
 
2692	int found = 0;
2693	int ret;
 
 
 
 
 
 
 
2694
2695	if (len) {
2696		type = filter_parse_regex(buff, len, &search, &not);
2697		search_len = strlen(search);
 
2698	}
2699
2700	mutex_lock(&ftrace_lock);
2701
2702	if (unlikely(ftrace_disabled))
2703		goto out_unlock;
2704
 
 
 
 
 
2705	do_for_each_ftrace_rec(pg, rec) {
2706		if (ftrace_match_record(rec, mod, search, search_len, type)) {
2707			ret = enter_record(hash, rec, not);
 
 
 
 
2708			if (ret < 0) {
2709				found = ret;
2710				goto out_unlock;
2711			}
2712			found = 1;
2713		}
2714	} while_for_each_ftrace_rec();
2715 out_unlock:
2716	mutex_unlock(&ftrace_lock);
2717
2718	return found;
2719}
2720
2721static int
2722ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
2723{
2724	return match_records(hash, buff, len, NULL, 0);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2725}
2726
2727static int
2728ftrace_match_module_records(struct ftrace_hash *hash, char *buff, char *mod)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2729{
2730	int not = 0;
 
2731
2732	/* blank or '*' mean the same */
2733	if (strcmp(buff, "*") == 0)
2734		buff[0] = 0;
2735
2736	/* handle the case of 'dont filter this module' */
2737	if (strcmp(buff, "!") == 0 || strcmp(buff, "!*") == 0) {
2738		buff[0] = 0;
2739		not = 1;
 
 
2740	}
 
2741
2742	return match_records(hash, buff, strlen(buff), mod, not);
2743}
 
2744
2745/*
2746 * We register the module command as a template to show others how
2747 * to register the a command as well.
2748 */
2749
2750static int
2751ftrace_mod_callback(struct ftrace_hash *hash,
2752		    char *func, char *cmd, char *param, int enable)
2753{
2754	char *mod;
2755	int ret = -EINVAL;
 
 
 
 
 
2756
2757	/*
2758	 * cmd == 'mod' because we only registered this func
2759	 * for the 'mod' ftrace_func_command.
2760	 * But if you register one func with multiple commands,
2761	 * you can tell which command was used by the cmd
2762	 * parameter.
2763	 */
 
 
2764
2765	/* we must have a module name */
2766	if (!param)
2767		return ret;
2768
2769	mod = strsep(&param, ":");
2770	if (!strlen(mod))
2771		return ret;
2772
2773	ret = ftrace_match_module_records(hash, func, mod);
2774	if (!ret)
2775		ret = -EINVAL;
2776	if (ret < 0)
2777		return ret;
2778
2779	return 0;
2780}
2781
2782static struct ftrace_func_command ftrace_mod_cmd = {
2783	.name			= "mod",
2784	.func			= ftrace_mod_callback,
2785};
2786
2787static int __init ftrace_mod_cmd_init(void)
2788{
2789	return register_ftrace_command(&ftrace_mod_cmd);
2790}
2791device_initcall(ftrace_mod_cmd_init);
2792
2793static void
2794function_trace_probe_call(unsigned long ip, unsigned long parent_ip)
2795{
2796	struct ftrace_func_probe *entry;
2797	struct hlist_head *hhd;
2798	struct hlist_node *n;
2799	unsigned long key;
2800
2801	key = hash_long(ip, FTRACE_HASH_BITS);
2802
2803	hhd = &ftrace_func_hash[key];
2804
2805	if (hlist_empty(hhd))
2806		return;
2807
2808	/*
2809	 * Disable preemption for these calls to prevent a RCU grace
2810	 * period. This syncs the hash iteration and freeing of items
2811	 * on the hash. rcu_read_lock is too dangerous here.
2812	 */
2813	preempt_disable_notrace();
2814	hlist_for_each_entry_rcu(entry, n, hhd, node) {
2815		if (entry->ip == ip)
2816			entry->ops->func(ip, parent_ip, &entry->data);
2817	}
2818	preempt_enable_notrace();
2819}
2820
2821static struct ftrace_ops trace_probe_ops __read_mostly =
2822{
2823	.func		= function_trace_probe_call,
2824};
2825
2826static int ftrace_probe_registered;
 
 
2827
2828static void __enable_ftrace_function_probe(void)
 
 
 
 
 
2829{
2830	int ret;
2831	int i;
2832
2833	if (ftrace_probe_registered)
2834		return;
 
 
 
 
 
 
2835
2836	for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2837		struct hlist_head *hhd = &ftrace_func_hash[i];
2838		if (hhd->first)
2839			break;
2840	}
2841	/* Nothing registered? */
2842	if (i == FTRACE_FUNC_HASHSIZE)
2843		return;
 
 
 
 
 
 
 
 
2844
2845	ret = __register_ftrace_function(&trace_probe_ops);
2846	if (!ret)
2847		ret = ftrace_startup(&trace_probe_ops, 0);
2848
2849	ftrace_probe_registered = 1;
 
2850}
2851
2852static void __disable_ftrace_function_probe(void)
 
 
 
 
 
 
 
 
 
2853{
2854	int ret;
2855	int i;
2856
2857	if (!ftrace_probe_registered)
2858		return;
 
2859
2860	for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2861		struct hlist_head *hhd = &ftrace_func_hash[i];
2862		if (hhd->first)
2863			return;
2864	}
2865
2866	/* no more funcs left */
2867	ret = __unregister_ftrace_function(&trace_probe_ops);
2868	if (!ret)
2869		ftrace_shutdown(&trace_probe_ops, 0);
2870
2871	ftrace_probe_registered = 0;
2872}
2873
 
 
2874
2875static void ftrace_free_entry_rcu(struct rcu_head *rhp)
 
 
 
 
 
 
 
 
 
 
 
2876{
2877	struct ftrace_func_probe *entry =
2878		container_of(rhp, struct ftrace_func_probe, rcu);
 
 
 
 
 
2879
2880	if (entry->ops->free)
2881		entry->ops->free(&entry->data);
 
 
2882	kfree(entry);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2883}
2884
 
 
 
 
 
 
 
 
2885
2886int
2887register_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2888			      void *data)
 
2889{
2890	struct ftrace_func_probe *entry;
2891	struct ftrace_page *pg;
2892	struct dyn_ftrace *rec;
2893	int type, len, not;
2894	unsigned long key;
2895	int count = 0;
2896	char *search;
 
 
2897
2898	type = filter_parse_regex(glob, strlen(glob), &search, &not);
2899	len = strlen(search);
2900
2901	/* we do not support '!' for function probes */
2902	if (WARN_ON(not))
2903		return -EINVAL;
2904
 
2905	mutex_lock(&ftrace_lock);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2906
2907	if (unlikely(ftrace_disabled))
2908		goto out_unlock;
2909
2910	do_for_each_ftrace_rec(pg, rec) {
2911
2912		if (!ftrace_match_record(rec, NULL, search, len, type))
2913			continue;
 
 
 
2914
2915		entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2916		if (!entry) {
2917			/* If we did not process any, then return error */
2918			if (!count)
2919				count = -ENOMEM;
2920			goto out_unlock;
2921		}
2922
2923		count++;
 
 
 
2924
2925		entry->data = data;
2926
2927		/*
2928		 * The caller might want to do something special
2929		 * for each function we find. We call the callback
2930		 * to give the caller an opportunity to do so.
2931		 */
2932		if (ops->callback) {
2933			if (ops->callback(rec->ip, &entry->data) < 0) {
2934				/* caller does not like this func */
2935				kfree(entry);
 
 
2936				continue;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2937			}
 
2938		}
 
2939
2940		entry->ops = ops;
2941		entry->ip = rec->ip;
2942
2943		key = hash_long(entry->ip, FTRACE_HASH_BITS);
2944		hlist_add_head_rcu(&entry->node, &ftrace_func_hash[key]);
 
 
 
2945
2946	} while_for_each_ftrace_rec();
2947	__enable_ftrace_function_probe();
 
 
 
 
 
 
 
 
2948
2949 out_unlock:
2950	mutex_unlock(&ftrace_lock);
2951
2952	return count;
2953}
 
 
 
2954
2955enum {
2956	PROBE_TEST_FUNC		= 1,
2957	PROBE_TEST_DATA		= 2
2958};
2959
2960static void
2961__unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
2962				  void *data, int flags)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2963{
2964	struct ftrace_func_probe *entry;
2965	struct hlist_node *n, *tmp;
 
 
 
 
 
 
 
2966	char str[KSYM_SYMBOL_LEN];
2967	int type = MATCH_FULL;
2968	int i, len = 0;
2969	char *search;
2970
2971	if (glob && (strcmp(glob, "*") == 0 || !strlen(glob)))
2972		glob = NULL;
2973	else if (glob) {
2974		int not;
2975
2976		type = filter_parse_regex(glob, strlen(glob), &search, &not);
2977		len = strlen(search);
 
2978
2979		/* we do not support '!' for function probes */
2980		if (WARN_ON(not))
2981			return;
2982	}
2983
2984	mutex_lock(&ftrace_lock);
2985	for (i = 0; i < FTRACE_FUNC_HASHSIZE; i++) {
2986		struct hlist_head *hhd = &ftrace_func_hash[i];
 
 
 
 
 
2987
2988		hlist_for_each_entry_safe(entry, n, tmp, hhd, node) {
 
 
2989
2990			/* break up if statements for readability */
2991			if ((flags & PROBE_TEST_FUNC) && entry->ops != ops)
2992				continue;
2993
2994			if ((flags & PROBE_TEST_DATA) && entry->data != data)
2995				continue;
 
 
 
 
2996
2997			/* do this last, since it is the most expensive */
2998			if (glob) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2999				kallsyms_lookup(entry->ip, NULL, NULL,
3000						NULL, str);
3001				if (!ftrace_match(str, glob, len, type))
3002					continue;
3003			}
3004
3005			hlist_del(&entry->node);
3006			call_rcu(&entry->rcu, ftrace_free_entry_rcu);
3007		}
3008	}
3009	__disable_ftrace_function_probe();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3010	mutex_unlock(&ftrace_lock);
3011}
3012
3013void
3014unregister_ftrace_function_probe(char *glob, struct ftrace_probe_ops *ops,
3015				void *data)
3016{
3017	__unregister_ftrace_function_probe(glob, ops, data,
3018					  PROBE_TEST_FUNC | PROBE_TEST_DATA);
3019}
3020
3021void
3022unregister_ftrace_function_probe_func(char *glob, struct ftrace_probe_ops *ops)
3023{
3024	__unregister_ftrace_function_probe(glob, ops, NULL, PROBE_TEST_FUNC);
 
 
 
3025}
3026
3027void unregister_ftrace_function_probe_all(char *glob)
3028{
3029	__unregister_ftrace_function_probe(glob, NULL, NULL, 0);
 
 
 
3030}
3031
3032static LIST_HEAD(ftrace_commands);
3033static DEFINE_MUTEX(ftrace_cmd_mutex);
3034
3035int register_ftrace_command(struct ftrace_func_command *cmd)
 
 
 
 
3036{
3037	struct ftrace_func_command *p;
3038	int ret = 0;
3039
3040	mutex_lock(&ftrace_cmd_mutex);
3041	list_for_each_entry(p, &ftrace_commands, list) {
3042		if (strcmp(cmd->name, p->name) == 0) {
3043			ret = -EBUSY;
3044			goto out_unlock;
3045		}
3046	}
3047	list_add(&cmd->list, &ftrace_commands);
3048 out_unlock:
3049	mutex_unlock(&ftrace_cmd_mutex);
3050
3051	return ret;
3052}
3053
3054int unregister_ftrace_command(struct ftrace_func_command *cmd)
 
 
 
 
3055{
3056	struct ftrace_func_command *p, *n;
3057	int ret = -ENODEV;
3058
3059	mutex_lock(&ftrace_cmd_mutex);
3060	list_for_each_entry_safe(p, n, &ftrace_commands, list) {
3061		if (strcmp(cmd->name, p->name) == 0) {
3062			ret = 0;
3063			list_del_init(&p->list);
3064			goto out_unlock;
3065		}
3066	}
3067 out_unlock:
3068	mutex_unlock(&ftrace_cmd_mutex);
3069
3070	return ret;
3071}
3072
3073static int ftrace_process_regex(struct ftrace_hash *hash,
3074				char *buff, int len, int enable)
3075{
 
 
3076	char *func, *command, *next = buff;
3077	struct ftrace_func_command *p;
3078	int ret = -EINVAL;
3079
3080	func = strsep(&next, ":");
3081
3082	if (!next) {
3083		ret = ftrace_match_records(hash, func, len);
3084		if (!ret)
3085			ret = -EINVAL;
3086		if (ret < 0)
3087			return ret;
3088		return 0;
3089	}
3090
3091	/* command found */
3092
3093	command = strsep(&next, ":");
3094
3095	mutex_lock(&ftrace_cmd_mutex);
3096	list_for_each_entry(p, &ftrace_commands, list) {
3097		if (strcmp(p->name, command) == 0) {
3098			ret = p->func(hash, func, command, next, enable);
3099			goto out_unlock;
3100		}
3101	}
3102 out_unlock:
3103	mutex_unlock(&ftrace_cmd_mutex);
3104
3105	return ret;
3106}
3107
3108static ssize_t
3109ftrace_regex_write(struct file *file, const char __user *ubuf,
3110		   size_t cnt, loff_t *ppos, int enable)
3111{
3112	struct ftrace_iterator *iter;
3113	struct trace_parser *parser;
3114	ssize_t ret, read;
3115
3116	if (!cnt)
3117		return 0;
3118
3119	mutex_lock(&ftrace_regex_lock);
3120
3121	ret = -ENODEV;
3122	if (unlikely(ftrace_disabled))
3123		goto out_unlock;
3124
3125	if (file->f_mode & FMODE_READ) {
3126		struct seq_file *m = file->private_data;
3127		iter = m->private;
3128	} else
3129		iter = file->private_data;
3130
 
 
 
 
 
3131	parser = &iter->parser;
3132	read = trace_get_user(parser, ubuf, cnt, ppos);
3133
3134	if (read >= 0 && trace_parser_loaded(parser) &&
3135	    !trace_parser_cont(parser)) {
3136		ret = ftrace_process_regex(iter->hash, parser->buffer,
3137					   parser->idx, enable);
3138		trace_parser_clear(parser);
3139		if (ret)
3140			goto out_unlock;
3141	}
3142
3143	ret = read;
3144out_unlock:
3145	mutex_unlock(&ftrace_regex_lock);
3146
3147	return ret;
3148}
3149
3150ssize_t
3151ftrace_filter_write(struct file *file, const char __user *ubuf,
3152		    size_t cnt, loff_t *ppos)
3153{
3154	return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
3155}
3156
3157ssize_t
3158ftrace_notrace_write(struct file *file, const char __user *ubuf,
3159		     size_t cnt, loff_t *ppos)
3160{
3161	return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
3162}
3163
3164static int
3165ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3166		 int reset, int enable)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3167{
3168	struct ftrace_hash **orig_hash;
3169	struct ftrace_hash *hash;
3170	int ret;
3171
3172	/* All global ops uses the global ops filters */
3173	if (ops->flags & FTRACE_OPS_FL_GLOBAL)
3174		ops = &global_ops;
3175
3176	if (unlikely(ftrace_disabled))
3177		return -ENODEV;
3178
 
 
3179	if (enable)
3180		orig_hash = &ops->filter_hash;
3181	else
3182		orig_hash = &ops->notrace_hash;
3183
3184	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
3185	if (!hash)
3186		return -ENOMEM;
3187
3188	mutex_lock(&ftrace_regex_lock);
3189	if (reset)
3190		ftrace_filter_reset(hash);
 
 
 
 
 
 
 
 
3191	if (buf && !ftrace_match_records(hash, buf, len)) {
3192		ret = -EINVAL;
3193		goto out_regex_unlock;
3194	}
 
 
 
 
 
3195
3196	mutex_lock(&ftrace_lock);
3197	ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3198	if (!ret && ops->flags & FTRACE_OPS_FL_ENABLED
3199	    && ftrace_enabled)
3200		ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3201
3202	mutex_unlock(&ftrace_lock);
3203
3204 out_regex_unlock:
3205	mutex_unlock(&ftrace_regex_lock);
3206
3207	free_ftrace_hash(hash);
3208	return ret;
3209}
3210
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3211/**
3212 * ftrace_set_filter - set a function to filter on in ftrace
3213 * @ops - the ops to set the filter with
3214 * @buf - the string that holds the function filter text.
3215 * @len - the length of the string.
3216 * @reset - non zero to reset all filters before applying this filter.
3217 *
3218 * Filters denote which functions should be enabled when tracing is enabled.
3219 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3220 */
3221int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
3222		       int len, int reset)
3223{
 
3224	return ftrace_set_regex(ops, buf, len, reset, 1);
3225}
3226EXPORT_SYMBOL_GPL(ftrace_set_filter);
3227
3228/**
3229 * ftrace_set_notrace - set a function to not trace in ftrace
3230 * @ops - the ops to set the notrace filter with
3231 * @buf - the string that holds the function notrace text.
3232 * @len - the length of the string.
3233 * @reset - non zero to reset all filters before applying this filter.
3234 *
3235 * Notrace Filters denote which functions should not be enabled when tracing
3236 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3237 * for tracing.
3238 */
3239int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
3240			int len, int reset)
3241{
 
3242	return ftrace_set_regex(ops, buf, len, reset, 0);
3243}
3244EXPORT_SYMBOL_GPL(ftrace_set_notrace);
3245/**
3246 * ftrace_set_filter - set a function to filter on in ftrace
3247 * @ops - the ops to set the filter with
3248 * @buf - the string that holds the function filter text.
3249 * @len - the length of the string.
3250 * @reset - non zero to reset all filters before applying this filter.
3251 *
3252 * Filters denote which functions should be enabled when tracing is enabled.
3253 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
3254 */
3255void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
3256{
3257	ftrace_set_regex(&global_ops, buf, len, reset, 1);
3258}
3259EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
3260
3261/**
3262 * ftrace_set_notrace - set a function to not trace in ftrace
3263 * @ops - the ops to set the notrace filter with
3264 * @buf - the string that holds the function notrace text.
3265 * @len - the length of the string.
3266 * @reset - non zero to reset all filters before applying this filter.
3267 *
3268 * Notrace Filters denote which functions should not be enabled when tracing
3269 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
3270 * for tracing.
3271 */
3272void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
3273{
3274	ftrace_set_regex(&global_ops, buf, len, reset, 0);
3275}
3276EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
3277
3278/*
3279 * command line interface to allow users to set filters on boot up.
3280 */
3281#define FTRACE_FILTER_SIZE		COMMAND_LINE_SIZE
3282static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
3283static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
3284
 
 
 
3285static int __init set_ftrace_notrace(char *str)
3286{
3287	strncpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
 
3288	return 1;
3289}
3290__setup("ftrace_notrace=", set_ftrace_notrace);
3291
3292static int __init set_ftrace_filter(char *str)
3293{
3294	strncpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
 
3295	return 1;
3296}
3297__setup("ftrace_filter=", set_ftrace_filter);
3298
3299#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3300static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
3301static int ftrace_set_func(unsigned long *array, int *idx, char *buffer);
 
3302
3303static int __init set_graph_function(char *str)
3304{
3305	strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
3306	return 1;
3307}
3308__setup("ftrace_graph_filter=", set_graph_function);
3309
3310static void __init set_ftrace_early_graph(char *buf)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3311{
3312	int ret;
3313	char *func;
 
 
 
 
 
3314
3315	while (buf) {
3316		func = strsep(&buf, ",");
3317		/* we allow only one expression at a time */
3318		ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3319				      func);
3320		if (ret)
3321			printk(KERN_DEBUG "ftrace: function %s not "
3322					  "traceable\n", func);
3323	}
 
 
 
 
 
3324}
3325#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3326
3327void __init
3328ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
3329{
3330	char *func;
3331
 
 
3332	while (buf) {
3333		func = strsep(&buf, ",");
3334		ftrace_set_regex(ops, func, strlen(func), 0, enable);
3335	}
3336}
3337
3338static void __init set_ftrace_early_filters(void)
3339{
3340	if (ftrace_filter_buf[0])
3341		ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
3342	if (ftrace_notrace_buf[0])
3343		ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
3344#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3345	if (ftrace_graph_buf[0])
3346		set_ftrace_early_graph(ftrace_graph_buf);
 
 
3347#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3348}
3349
3350int ftrace_regex_release(struct inode *inode, struct file *file)
3351{
3352	struct seq_file *m = (struct seq_file *)file->private_data;
3353	struct ftrace_iterator *iter;
3354	struct ftrace_hash **orig_hash;
3355	struct trace_parser *parser;
3356	int filter_hash;
3357	int ret;
3358
3359	mutex_lock(&ftrace_regex_lock);
3360	if (file->f_mode & FMODE_READ) {
3361		iter = m->private;
3362
3363		seq_release(inode, file);
3364	} else
3365		iter = file->private_data;
3366
3367	parser = &iter->parser;
3368	if (trace_parser_loaded(parser)) {
3369		parser->buffer[parser->idx] = 0;
3370		ftrace_match_records(iter->hash, parser->buffer, parser->idx);
3371	}
3372
3373	trace_parser_put(parser);
3374
 
 
3375	if (file->f_mode & FMODE_WRITE) {
3376		filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
3377
3378		if (filter_hash)
3379			orig_hash = &iter->ops->filter_hash;
3380		else
3381			orig_hash = &iter->ops->notrace_hash;
 
 
3382
3383		mutex_lock(&ftrace_lock);
3384		ret = ftrace_hash_move(iter->ops, filter_hash,
3385				       orig_hash, iter->hash);
3386		if (!ret && (iter->ops->flags & FTRACE_OPS_FL_ENABLED)
3387		    && ftrace_enabled)
3388			ftrace_run_update_code(FTRACE_UPDATE_CALLS);
3389
3390		mutex_unlock(&ftrace_lock);
 
 
 
3391	}
 
 
3392	free_ftrace_hash(iter->hash);
 
 
3393	kfree(iter);
3394
3395	mutex_unlock(&ftrace_regex_lock);
3396	return 0;
3397}
3398
3399static const struct file_operations ftrace_avail_fops = {
3400	.open = ftrace_avail_open,
3401	.read = seq_read,
3402	.llseek = seq_lseek,
3403	.release = seq_release_private,
3404};
3405
3406static const struct file_operations ftrace_enabled_fops = {
3407	.open = ftrace_enabled_open,
3408	.read = seq_read,
3409	.llseek = seq_lseek,
3410	.release = seq_release_private,
3411};
3412
3413static const struct file_operations ftrace_filter_fops = {
3414	.open = ftrace_filter_open,
3415	.read = seq_read,
3416	.write = ftrace_filter_write,
3417	.llseek = ftrace_regex_lseek,
3418	.release = ftrace_regex_release,
3419};
3420
3421static const struct file_operations ftrace_notrace_fops = {
3422	.open = ftrace_notrace_open,
3423	.read = seq_read,
3424	.write = ftrace_notrace_write,
3425	.llseek = ftrace_regex_lseek,
3426	.release = ftrace_regex_release,
3427};
3428
3429#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3430
3431static DEFINE_MUTEX(graph_lock);
3432
3433int ftrace_graph_count;
3434int ftrace_graph_filter_enabled;
3435unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3436
3437static void *
3438__g_next(struct seq_file *m, loff_t *pos)
3439{
3440	if (*pos >= ftrace_graph_count)
 
 
 
 
 
3441		return NULL;
3442	return &ftrace_graph_funcs[*pos];
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3443}
3444
3445static void *
3446g_next(struct seq_file *m, void *v, loff_t *pos)
3447{
3448	(*pos)++;
3449	return __g_next(m, pos);
3450}
3451
3452static void *g_start(struct seq_file *m, loff_t *pos)
3453{
 
 
3454	mutex_lock(&graph_lock);
3455
 
 
 
 
 
 
 
3456	/* Nothing, tell g_show to print all functions are enabled */
3457	if (!ftrace_graph_filter_enabled && !*pos)
3458		return (void *)1;
3459
 
 
3460	return __g_next(m, pos);
3461}
3462
3463static void g_stop(struct seq_file *m, void *p)
3464{
3465	mutex_unlock(&graph_lock);
3466}
3467
3468static int g_show(struct seq_file *m, void *v)
3469{
3470	unsigned long *ptr = v;
3471
3472	if (!ptr)
3473		return 0;
3474
3475	if (ptr == (unsigned long *)1) {
3476		seq_printf(m, "#### all functions enabled ####\n");
 
 
 
 
 
3477		return 0;
3478	}
3479
3480	seq_printf(m, "%ps\n", (void *)*ptr);
3481
3482	return 0;
3483}
3484
3485static const struct seq_operations ftrace_graph_seq_ops = {
3486	.start = g_start,
3487	.next = g_next,
3488	.stop = g_stop,
3489	.show = g_show,
3490};
3491
3492static int
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3493ftrace_graph_open(struct inode *inode, struct file *file)
3494{
3495	int ret = 0;
 
3496
3497	if (unlikely(ftrace_disabled))
3498		return -ENODEV;
3499
 
 
 
 
3500	mutex_lock(&graph_lock);
3501	if ((file->f_mode & FMODE_WRITE) &&
3502	    (file->f_flags & O_TRUNC)) {
3503		ftrace_graph_filter_enabled = 0;
3504		ftrace_graph_count = 0;
3505		memset(ftrace_graph_funcs, 0, sizeof(ftrace_graph_funcs));
3506	}
 
 
 
 
3507	mutex_unlock(&graph_lock);
 
 
3508
3509	if (file->f_mode & FMODE_READ)
3510		ret = seq_open(file, &ftrace_graph_seq_ops);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3511
 
3512	return ret;
3513}
3514
3515static int
3516ftrace_graph_release(struct inode *inode, struct file *file)
3517{
3518	if (file->f_mode & FMODE_READ)
 
 
 
 
 
 
 
 
3519		seq_release(inode, file);
3520	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3521}
3522
3523static int
3524ftrace_set_func(unsigned long *array, int *idx, char *buffer)
3525{
 
3526	struct dyn_ftrace *rec;
3527	struct ftrace_page *pg;
3528	int search_len;
3529	int fail = 1;
3530	int type, not;
3531	char *search;
3532	bool exists;
3533	int i;
3534
3535	/* decode regex */
3536	type = filter_parse_regex(buffer, strlen(buffer), &search, &not);
3537	if (!not && *idx >= FTRACE_GRAPH_MAX_FUNCS)
3538		return -EBUSY;
3539
3540	search_len = strlen(search);
3541
3542	mutex_lock(&ftrace_lock);
3543
3544	if (unlikely(ftrace_disabled)) {
3545		mutex_unlock(&ftrace_lock);
3546		return -ENODEV;
3547	}
3548
3549	do_for_each_ftrace_rec(pg, rec) {
3550
3551		if (ftrace_match_record(rec, NULL, search, search_len, type)) {
3552			/* if it is in the array */
3553			exists = false;
3554			for (i = 0; i < *idx; i++) {
3555				if (array[i] == rec->ip) {
3556					exists = true;
3557					break;
3558				}
3559			}
3560
3561			if (!not) {
3562				fail = 0;
3563				if (!exists) {
3564					array[(*idx)++] = rec->ip;
3565					if (*idx >= FTRACE_GRAPH_MAX_FUNCS)
3566						goto out;
3567				}
3568			} else {
3569				if (exists) {
3570					array[i] = array[--(*idx)];
3571					array[*idx] = 0;
3572					fail = 0;
3573				}
3574			}
3575		}
3576	} while_for_each_ftrace_rec();
3577out:
3578	mutex_unlock(&ftrace_lock);
3579
3580	if (fail)
3581		return -EINVAL;
3582
3583	ftrace_graph_filter_enabled = 1;
3584	return 0;
3585}
3586
3587static ssize_t
3588ftrace_graph_write(struct file *file, const char __user *ubuf,
3589		   size_t cnt, loff_t *ppos)
3590{
3591	struct trace_parser parser;
3592	ssize_t read, ret;
 
3593
3594	if (!cnt)
3595		return 0;
3596
3597	mutex_lock(&graph_lock);
3598
3599	if (trace_parser_get_init(&parser, FTRACE_BUFF_MAX)) {
3600		ret = -ENOMEM;
3601		goto out_unlock;
3602	}
3603
3604	read = trace_get_user(&parser, ubuf, cnt, ppos);
3605
3606	if (read >= 0 && trace_parser_loaded((&parser))) {
3607		parser.buffer[parser.idx] = 0;
3608
3609		/* we allow only one expression at a time */
3610		ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count,
3611					parser.buffer);
3612		if (ret)
3613			goto out_free;
3614	}
3615
3616	ret = read;
 
 
 
3617
3618out_free:
3619	trace_parser_put(&parser);
3620out_unlock:
3621	mutex_unlock(&graph_lock);
3622
3623	return ret;
3624}
3625
3626static const struct file_operations ftrace_graph_fops = {
3627	.open		= ftrace_graph_open,
3628	.read		= seq_read,
3629	.write		= ftrace_graph_write,
 
 
 
 
 
 
 
 
 
3630	.release	= ftrace_graph_release,
3631	.llseek		= seq_lseek,
3632};
3633#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3634
3635static __init int ftrace_init_dyn_debugfs(struct dentry *d_tracer)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3636{
3637
3638	trace_create_file("available_filter_functions", 0444,
3639			d_tracer, NULL, &ftrace_avail_fops);
3640
3641	trace_create_file("enabled_functions", 0444,
3642			d_tracer, NULL, &ftrace_enabled_fops);
3643
3644	trace_create_file("set_ftrace_filter", 0644, d_tracer,
3645			NULL, &ftrace_filter_fops);
3646
3647	trace_create_file("set_ftrace_notrace", 0644, d_tracer,
3648				    NULL, &ftrace_notrace_fops);
3649
3650#ifdef CONFIG_FUNCTION_GRAPH_TRACER
3651	trace_create_file("set_graph_function", 0444, d_tracer,
3652				    NULL,
3653				    &ftrace_graph_fops);
 
 
 
3654#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
3655
3656	return 0;
3657}
3658
3659static int ftrace_cmp_ips(const void *a, const void *b)
3660{
3661	const unsigned long *ipa = a;
3662	const unsigned long *ipb = b;
3663
3664	if (*ipa > *ipb)
3665		return 1;
3666	if (*ipa < *ipb)
3667		return -1;
3668	return 0;
3669}
3670
3671static void ftrace_swap_ips(void *a, void *b, int size)
3672{
3673	unsigned long *ipa = a;
3674	unsigned long *ipb = b;
3675	unsigned long t;
3676
3677	t = *ipa;
3678	*ipa = *ipb;
3679	*ipb = t;
3680}
3681
3682static int ftrace_process_locs(struct module *mod,
3683			       unsigned long *start,
3684			       unsigned long *end)
3685{
3686	struct ftrace_page *start_pg;
3687	struct ftrace_page *pg;
3688	struct dyn_ftrace *rec;
3689	unsigned long count;
3690	unsigned long *p;
3691	unsigned long addr;
3692	unsigned long flags = 0; /* Shut up gcc */
3693	int ret = -ENOMEM;
3694
3695	count = end - start;
3696
3697	if (!count)
3698		return 0;
3699
3700	sort(start, count, sizeof(*start),
3701	     ftrace_cmp_ips, ftrace_swap_ips);
3702
3703	start_pg = ftrace_allocate_pages(count);
3704	if (!start_pg)
3705		return -ENOMEM;
3706
3707	mutex_lock(&ftrace_lock);
3708
3709	/*
3710	 * Core and each module needs their own pages, as
3711	 * modules will free them when they are removed.
3712	 * Force a new page to be allocated for modules.
3713	 */
3714	if (!mod) {
3715		WARN_ON(ftrace_pages || ftrace_pages_start);
3716		/* First initialization */
3717		ftrace_pages = ftrace_pages_start = start_pg;
3718	} else {
3719		if (!ftrace_pages)
3720			goto out;
3721
3722		if (WARN_ON(ftrace_pages->next)) {
3723			/* Hmm, we have free pages? */
3724			while (ftrace_pages->next)
3725				ftrace_pages = ftrace_pages->next;
3726		}
3727
3728		ftrace_pages->next = start_pg;
3729	}
3730
3731	p = start;
3732	pg = start_pg;
3733	while (p < end) {
3734		addr = ftrace_call_adjust(*p++);
3735		/*
3736		 * Some architecture linkers will pad between
3737		 * the different mcount_loc sections of different
3738		 * object files to satisfy alignments.
3739		 * Skip any NULL pointers.
3740		 */
3741		if (!addr)
3742			continue;
3743
3744		if (pg->index == pg->size) {
3745			/* We should have allocated enough */
3746			if (WARN_ON(!pg->next))
3747				break;
3748			pg = pg->next;
3749		}
3750
3751		rec = &pg->records[pg->index++];
3752		rec->ip = addr;
3753	}
3754
3755	/* We should have used all pages */
3756	WARN_ON(pg->next);
3757
3758	/* Assign the last page to ftrace_pages */
3759	ftrace_pages = pg;
3760
3761	/* These new locations need to be initialized */
3762	ftrace_new_pgs = start_pg;
3763
3764	/*
3765	 * We only need to disable interrupts on start up
3766	 * because we are modifying code that an interrupt
3767	 * may execute, and the modification is not atomic.
3768	 * But for modules, nothing runs the code we modify
3769	 * until we are finished with it, and there's no
3770	 * reason to cause large interrupt latencies while we do it.
3771	 */
3772	if (!mod)
3773		local_irq_save(flags);
3774	ftrace_update_code(mod);
3775	if (!mod)
3776		local_irq_restore(flags);
3777	ret = 0;
3778 out:
3779	mutex_unlock(&ftrace_lock);
3780
3781	return ret;
3782}
3783
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3784#ifdef CONFIG_MODULES
3785
3786#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
3787
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3788void ftrace_release_mod(struct module *mod)
3789{
 
 
3790	struct dyn_ftrace *rec;
3791	struct ftrace_page **last_pg;
 
3792	struct ftrace_page *pg;
3793	int order;
3794
3795	mutex_lock(&ftrace_lock);
3796
3797	if (ftrace_disabled)
3798		goto out_unlock;
3799
 
 
 
 
 
 
 
 
3800	/*
3801	 * Each module has its own ftrace_pages, remove
3802	 * them from the list.
3803	 */
3804	last_pg = &ftrace_pages_start;
3805	for (pg = ftrace_pages_start; pg; pg = *last_pg) {
3806		rec = &pg->records[0];
3807		if (within_module_core(rec->ip, mod)) {
 
3808			/*
3809			 * As core pages are first, the first
3810			 * page should never be a module page.
3811			 */
3812			if (WARN_ON(pg == ftrace_pages_start))
3813				goto out_unlock;
3814
3815			/* Check if we are deleting the last page */
3816			if (pg == ftrace_pages)
3817				ftrace_pages = next_to_ftrace_page(last_pg);
3818
 
3819			*last_pg = pg->next;
3820			order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3821			free_pages((unsigned long)pg->records, order);
3822			kfree(pg);
3823		} else
3824			last_pg = &pg->next;
3825	}
3826 out_unlock:
3827	mutex_unlock(&ftrace_lock);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3828}
3829
3830static void ftrace_init_module(struct module *mod,
3831			       unsigned long *start, unsigned long *end)
3832{
3833	if (ftrace_disabled || start == end)
3834		return;
3835	ftrace_process_locs(mod, start, end);
 
 
3836}
3837
3838static int ftrace_module_notify(struct notifier_block *self,
3839				unsigned long val, void *data)
3840{
3841	struct module *mod = data;
 
 
 
 
 
3842
3843	switch (val) {
3844	case MODULE_STATE_COMING:
3845		ftrace_init_module(mod, mod->ftrace_callsites,
3846				   mod->ftrace_callsites +
3847				   mod->num_ftrace_callsites);
3848		break;
3849	case MODULE_STATE_GOING:
3850		ftrace_release_mod(mod);
3851		break;
 
 
 
3852	}
3853
3854	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3855}
 
3856#else
3857static int ftrace_module_notify(struct notifier_block *self,
3858				unsigned long val, void *data)
 
 
 
3859{
3860	return 0;
3861}
3862#endif /* CONFIG_MODULES */
3863
3864struct notifier_block ftrace_module_nb = {
3865	.notifier_call = ftrace_module_notify,
3866	.priority = 0,
3867};
3868
3869extern unsigned long __start_mcount_loc[];
3870extern unsigned long __stop_mcount_loc[];
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3871
3872void __init ftrace_init(void)
3873{
3874	unsigned long count, addr, flags;
 
 
3875	int ret;
3876
3877	/* Keep the ftrace pointer to the stub */
3878	addr = (unsigned long)ftrace_stub;
3879
3880	local_irq_save(flags);
3881	ftrace_dyn_arch_init(&addr);
3882	local_irq_restore(flags);
3883
3884	/* ftrace_dyn_arch_init places the return code in addr */
3885	if (addr)
3886		goto failed;
3887
3888	count = __stop_mcount_loc - __start_mcount_loc;
3889
3890	ret = ftrace_dyn_table_alloc(count);
3891	if (ret)
3892		goto failed;
 
 
 
 
3893
3894	last_ftrace_enabled = ftrace_enabled = 1;
3895
3896	ret = ftrace_process_locs(NULL,
3897				  __start_mcount_loc,
3898				  __stop_mcount_loc);
3899
3900	ret = register_module_notifier(&ftrace_module_nb);
3901	if (ret)
3902		pr_warning("Failed to register trace ftrace module notifier\n");
3903
3904	set_ftrace_early_filters();
3905
3906	return;
3907 failed:
3908	ftrace_disabled = 1;
3909}
3910
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3911#else
3912
3913static struct ftrace_ops global_ops = {
3914	.func			= ftrace_stub,
 
 
 
3915};
3916
3917static int __init ftrace_nodyn_init(void)
3918{
3919	ftrace_enabled = 1;
3920	return 0;
3921}
3922device_initcall(ftrace_nodyn_init);
3923
3924static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
3925static inline void ftrace_startup_enable(int command) { }
3926/* Keep as macros so we do not need to define the commands */
3927# define ftrace_startup(ops, command)			\
3928	({						\
3929		(ops)->flags |= FTRACE_OPS_FL_ENABLED;	\
3930		0;					\
3931	})
3932# define ftrace_shutdown(ops, command)	do { } while (0)
3933# define ftrace_startup_sysctl()	do { } while (0)
3934# define ftrace_shutdown_sysctl()	do { } while (0)
3935
3936static inline int
3937ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
3938{
3939	return 1;
3940}
3941
3942#endif /* CONFIG_DYNAMIC_FTRACE */
3943
3944static void
3945ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3946{
3947	struct ftrace_ops *op;
 
3948
3949	if (unlikely(trace_recursion_test(TRACE_CONTROL_BIT)))
 
3950		return;
3951
3952	/*
3953	 * Some of the ops may be dynamically allocated,
3954	 * they must be freed after a synchronize_sched().
3955	 */
3956	preempt_disable_notrace();
3957	trace_recursion_set(TRACE_CONTROL_BIT);
3958	op = rcu_dereference_raw(ftrace_control_list);
3959	while (op != &ftrace_list_end) {
3960		if (!ftrace_function_local_disabled(op) &&
3961		    ftrace_ops_test(op, ip))
3962			op->func(ip, parent_ip);
3963
3964		op = rcu_dereference_raw(op->next);
3965	};
3966	trace_recursion_clear(TRACE_CONTROL_BIT);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3967	preempt_enable_notrace();
 
3968}
3969
3970static struct ftrace_ops control_ops = {
3971	.func = ftrace_ops_control_func,
3972};
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3973
3974static void
3975ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
 
 
 
 
 
3976{
3977	struct ftrace_ops *op;
3978
3979	if (unlikely(trace_recursion_test(TRACE_INTERNAL_BIT)))
 
 
 
 
3980		return;
3981
3982	trace_recursion_set(TRACE_INTERNAL_BIT);
3983	/*
3984	 * Some of the ops may be dynamically allocated,
3985	 * they must be freed after a synchronize_sched().
3986	 */
3987	preempt_disable_notrace();
3988	op = rcu_dereference_raw(ftrace_ops_list);
3989	while (op != &ftrace_list_end) {
3990		if (ftrace_ops_test(op, ip))
3991			op->func(ip, parent_ip);
3992		op = rcu_dereference_raw(op->next);
3993	};
3994	preempt_enable_notrace();
3995	trace_recursion_clear(TRACE_INTERNAL_BIT);
3996}
3997
3998static void clear_ftrace_swapper(void)
3999{
4000	struct task_struct *p;
4001	int cpu;
4002
4003	get_online_cpus();
4004	for_each_online_cpu(cpu) {
4005		p = idle_task(cpu);
4006		clear_tsk_trace_trace(p);
4007	}
4008	put_online_cpus();
4009}
 
4010
4011static void set_ftrace_swapper(void)
 
 
 
 
 
 
 
 
 
 
 
4012{
4013	struct task_struct *p;
4014	int cpu;
 
 
 
 
 
4015
4016	get_online_cpus();
4017	for_each_online_cpu(cpu) {
4018		p = idle_task(cpu);
4019		set_tsk_trace_trace(p);
4020	}
4021	put_online_cpus();
4022}
4023
4024static void clear_ftrace_pid(struct pid *pid)
 
 
4025{
4026	struct task_struct *p;
 
4027
4028	rcu_read_lock();
4029	do_each_pid_task(pid, PIDTYPE_PID, p) {
4030		clear_tsk_trace_trace(p);
4031	} while_each_pid_task(pid, PIDTYPE_PID, p);
4032	rcu_read_unlock();
4033
4034	put_pid(pid);
 
4035}
4036
4037static void set_ftrace_pid(struct pid *pid)
 
 
 
4038{
4039	struct task_struct *p;
 
4040
4041	rcu_read_lock();
4042	do_each_pid_task(pid, PIDTYPE_PID, p) {
4043		set_tsk_trace_trace(p);
4044	} while_each_pid_task(pid, PIDTYPE_PID, p);
4045	rcu_read_unlock();
4046}
4047
4048static void clear_ftrace_pid_task(struct pid *pid)
 
4049{
4050	if (pid == ftrace_swapper_pid)
4051		clear_ftrace_swapper();
4052	else
4053		clear_ftrace_pid(pid);
 
4054}
4055
4056static void set_ftrace_pid_task(struct pid *pid)
4057{
4058	if (pid == ftrace_swapper_pid)
4059		set_ftrace_swapper();
4060	else
4061		set_ftrace_pid(pid);
 
 
 
 
 
 
 
4062}
4063
4064static int ftrace_pid_add(int p)
4065{
4066	struct pid *pid;
4067	struct ftrace_pid *fpid;
4068	int ret = -EINVAL;
4069
4070	mutex_lock(&ftrace_lock);
4071
4072	if (!p)
4073		pid = ftrace_swapper_pid;
4074	else
4075		pid = find_get_pid(p);
4076
4077	if (!pid)
4078		goto out;
4079
4080	ret = 0;
4081
4082	list_for_each_entry(fpid, &ftrace_pids, list)
4083		if (fpid->pid == pid)
4084			goto out_put;
 
4085
4086	ret = -ENOMEM;
4087
4088	fpid = kmalloc(sizeof(*fpid), GFP_KERNEL);
4089	if (!fpid)
4090		goto out_put;
4091
4092	list_add(&fpid->list, &ftrace_pids);
4093	fpid->pid = pid;
4094
4095	set_ftrace_pid_task(pid);
 
4096
4097	ftrace_update_pid_func();
4098	ftrace_startup_enable(0);
4099
4100	mutex_unlock(&ftrace_lock);
4101	return 0;
 
4102
4103out_put:
4104	if (pid != ftrace_swapper_pid)
4105		put_pid(pid);
4106
4107out:
4108	mutex_unlock(&ftrace_lock);
4109	return ret;
4110}
4111
4112static void ftrace_pid_reset(void)
4113{
4114	struct ftrace_pid *fpid, *safe;
4115
4116	mutex_lock(&ftrace_lock);
4117	list_for_each_entry_safe(fpid, safe, &ftrace_pids, list) {
4118		struct pid *pid = fpid->pid;
4119
4120		clear_ftrace_pid_task(pid);
4121
4122		list_del(&fpid->list);
4123		kfree(fpid);
4124	}
4125
4126	ftrace_update_pid_func();
4127	ftrace_startup_enable(0);
4128
4129	mutex_unlock(&ftrace_lock);
4130}
4131
 
 
 
4132static void *fpid_start(struct seq_file *m, loff_t *pos)
 
4133{
 
 
 
4134	mutex_lock(&ftrace_lock);
 
 
 
4135
4136	if (list_empty(&ftrace_pids) && (!*pos))
4137		return (void *) 1;
4138
4139	return seq_list_start(&ftrace_pids, *pos);
4140}
4141
4142static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
4143{
4144	if (v == (void *)1)
 
 
 
4145		return NULL;
4146
4147	return seq_list_next(v, &ftrace_pids, pos);
4148}
4149
4150static void fpid_stop(struct seq_file *m, void *p)
 
4151{
 
4152	mutex_unlock(&ftrace_lock);
4153}
4154
4155static int fpid_show(struct seq_file *m, void *v)
4156{
4157	const struct ftrace_pid *fpid = list_entry(v, struct ftrace_pid, list);
4158
4159	if (v == (void *)1) {
4160		seq_printf(m, "no pid\n");
4161		return 0;
4162	}
4163
4164	if (fpid->pid == ftrace_swapper_pid)
4165		seq_printf(m, "swapper tasks\n");
4166	else
4167		seq_printf(m, "%u\n", pid_vnr(fpid->pid));
4168
4169	return 0;
4170}
4171
4172static const struct seq_operations ftrace_pid_sops = {
4173	.start = fpid_start,
4174	.next = fpid_next,
4175	.stop = fpid_stop,
4176	.show = fpid_show,
4177};
4178
4179static int
4180ftrace_pid_open(struct inode *inode, struct file *file)
4181{
 
 
4182	int ret = 0;
4183
 
 
 
 
4184	if ((file->f_mode & FMODE_WRITE) &&
4185	    (file->f_flags & O_TRUNC))
4186		ftrace_pid_reset();
4187
4188	if (file->f_mode & FMODE_READ)
4189		ret = seq_open(file, &ftrace_pid_sops);
 
 
 
 
 
 
4190
4191	return ret;
4192}
4193
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4194static ssize_t
4195ftrace_pid_write(struct file *filp, const char __user *ubuf,
4196		   size_t cnt, loff_t *ppos)
4197{
4198	char buf[64], *tmp;
4199	long val;
4200	int ret;
 
 
4201
4202	if (cnt >= sizeof(buf))
4203		return -EINVAL;
4204
4205	if (copy_from_user(&buf, ubuf, cnt))
4206		return -EFAULT;
 
 
 
 
 
 
 
 
4207
4208	buf[cnt] = 0;
 
 
 
 
 
 
4209
4210	/*
4211	 * Allow "echo > set_ftrace_pid" or "echo -n '' > set_ftrace_pid"
4212	 * to clean the filter quietly.
 
4213	 */
4214	tmp = strstrip(buf);
4215	if (strlen(tmp) == 0)
4216		return 1;
4217
4218	ret = strict_strtol(tmp, 10, &val);
4219	if (ret < 0)
4220		return ret;
 
4221
4222	ret = ftrace_pid_add(val);
 
4223
4224	return ret ? ret : cnt;
4225}
4226
4227static int
4228ftrace_pid_release(struct inode *inode, struct file *file)
4229{
4230	if (file->f_mode & FMODE_READ)
4231		seq_release(inode, file);
4232
4233	return 0;
 
 
4234}
4235
4236static const struct file_operations ftrace_pid_fops = {
4237	.open		= ftrace_pid_open,
4238	.write		= ftrace_pid_write,
4239	.read		= seq_read,
4240	.llseek		= seq_lseek,
4241	.release	= ftrace_pid_release,
4242};
4243
4244static __init int ftrace_init_debugfs(void)
4245{
4246	struct dentry *d_tracer;
4247
4248	d_tracer = tracing_init_dentry();
4249	if (!d_tracer)
4250		return 0;
4251
4252	ftrace_init_dyn_debugfs(d_tracer);
4253
4254	trace_create_file("set_ftrace_pid", 0644, d_tracer,
4255			    NULL, &ftrace_pid_fops);
 
4256
4257	ftrace_profile_debugfs(d_tracer);
 
 
 
 
4258
4259	return 0;
 
4260}
4261fs_initcall(ftrace_init_debugfs);
4262
4263/**
4264 * ftrace_kill - kill ftrace
4265 *
4266 * This function should be used by panic code. It stops ftrace
4267 * but in a not so nice way. If you need to simply kill ftrace
4268 * from a non-atomic section, use ftrace_kill.
4269 */
4270void ftrace_kill(void)
4271{
4272	ftrace_disabled = 1;
4273	ftrace_enabled = 0;
4274	clear_ftrace_function();
4275}
4276
4277/**
4278 * Test if ftrace is dead or not.
4279 */
4280int ftrace_is_dead(void)
4281{
4282	return ftrace_disabled;
4283}
4284
4285/**
4286 * register_ftrace_function - register a function for profiling
4287 * @ops - ops structure that holds the function for profiling.
4288 *
4289 * Register a function to be called by all functions in the
4290 * kernel.
4291 *
4292 * Note: @ops->func and all the functions it calls must be labeled
4293 *       with "notrace", otherwise it will go into a
4294 *       recursive loop.
4295 */
4296int register_ftrace_function(struct ftrace_ops *ops)
4297{
4298	int ret = -1;
4299
4300	mutex_lock(&ftrace_lock);
4301
4302	if (unlikely(ftrace_disabled))
4303		goto out_unlock;
4304
4305	ret = __register_ftrace_function(ops);
4306	if (!ret)
4307		ret = ftrace_startup(ops, 0);
4308
 
4309
4310 out_unlock:
4311	mutex_unlock(&ftrace_lock);
 
4312	return ret;
4313}
4314EXPORT_SYMBOL_GPL(register_ftrace_function);
4315
4316/**
4317 * unregister_ftrace_function - unregister a function for profiling.
4318 * @ops - ops structure that holds the function to unregister
4319 *
4320 * Unregister a function that was added to be called by ftrace profiling.
4321 */
4322int unregister_ftrace_function(struct ftrace_ops *ops)
4323{
4324	int ret;
4325
4326	mutex_lock(&ftrace_lock);
4327	ret = __unregister_ftrace_function(ops);
4328	if (!ret)
4329		ftrace_shutdown(ops, 0);
4330	mutex_unlock(&ftrace_lock);
4331
4332	return ret;
4333}
4334EXPORT_SYMBOL_GPL(unregister_ftrace_function);
4335
4336int
4337ftrace_enable_sysctl(struct ctl_table *table, int write,
4338		     void __user *buffer, size_t *lenp,
4339		     loff_t *ppos)
4340{
4341	int ret = -ENODEV;
4342
4343	mutex_lock(&ftrace_lock);
4344
4345	if (unlikely(ftrace_disabled))
4346		goto out;
4347
4348	ret = proc_dointvec(table, write, buffer, lenp, ppos);
4349
4350	if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
4351		goto out;
4352
4353	last_ftrace_enabled = !!ftrace_enabled;
4354
4355	if (ftrace_enabled) {
4356
4357		ftrace_startup_sysctl();
4358
4359		/* we are starting ftrace again */
4360		if (ftrace_ops_list != &ftrace_list_end) {
4361			if (ftrace_ops_list->next == &ftrace_list_end)
4362				ftrace_trace_function = ftrace_ops_list->func;
4363			else
4364				ftrace_trace_function = ftrace_ops_list_func;
4365		}
4366
4367	} else {
4368		/* stopping ftrace calls (just send to ftrace_stub) */
4369		ftrace_trace_function = ftrace_stub;
4370
4371		ftrace_shutdown_sysctl();
4372	}
4373
4374 out:
4375	mutex_unlock(&ftrace_lock);
4376	return ret;
4377}
4378
4379#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4380
4381static int ftrace_graph_active;
4382static struct notifier_block ftrace_suspend_notifier;
4383
4384int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace)
4385{
4386	return 0;
4387}
4388
4389/* The callbacks that hook a function */
4390trace_func_graph_ret_t ftrace_graph_return =
4391			(trace_func_graph_ret_t)ftrace_stub;
4392trace_func_graph_ent_t ftrace_graph_entry = ftrace_graph_entry_stub;
4393
4394/* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
4395static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
4396{
4397	int i;
4398	int ret = 0;
4399	unsigned long flags;
4400	int start = 0, end = FTRACE_RETSTACK_ALLOC_SIZE;
4401	struct task_struct *g, *t;
4402
4403	for (i = 0; i < FTRACE_RETSTACK_ALLOC_SIZE; i++) {
4404		ret_stack_list[i] = kmalloc(FTRACE_RETFUNC_DEPTH
4405					* sizeof(struct ftrace_ret_stack),
4406					GFP_KERNEL);
4407		if (!ret_stack_list[i]) {
4408			start = 0;
4409			end = i;
4410			ret = -ENOMEM;
4411			goto free;
4412		}
4413	}
4414
4415	read_lock_irqsave(&tasklist_lock, flags);
4416	do_each_thread(g, t) {
4417		if (start == end) {
4418			ret = -EAGAIN;
4419			goto unlock;
4420		}
4421
4422		if (t->ret_stack == NULL) {
4423			atomic_set(&t->tracing_graph_pause, 0);
4424			atomic_set(&t->trace_overrun, 0);
4425			t->curr_ret_stack = -1;
4426			/* Make sure the tasks see the -1 first: */
4427			smp_wmb();
4428			t->ret_stack = ret_stack_list[start++];
4429		}
4430	} while_each_thread(g, t);
4431
4432unlock:
4433	read_unlock_irqrestore(&tasklist_lock, flags);
4434free:
4435	for (i = start; i < end; i++)
4436		kfree(ret_stack_list[i]);
4437	return ret;
4438}
4439
4440static void
4441ftrace_graph_probe_sched_switch(void *ignore,
4442			struct task_struct *prev, struct task_struct *next)
4443{
4444	unsigned long long timestamp;
4445	int index;
4446
4447	/*
4448	 * Does the user want to count the time a function was asleep.
4449	 * If so, do not update the time stamps.
4450	 */
4451	if (trace_flags & TRACE_ITER_SLEEP_TIME)
4452		return;
4453
4454	timestamp = trace_clock_local();
4455
4456	prev->ftrace_timestamp = timestamp;
4457
4458	/* only process tasks that we timestamped */
4459	if (!next->ftrace_timestamp)
4460		return;
4461
4462	/*
4463	 * Update all the counters in next to make up for the
4464	 * time next was sleeping.
4465	 */
4466	timestamp -= next->ftrace_timestamp;
4467
4468	for (index = next->curr_ret_stack; index >= 0; index--)
4469		next->ret_stack[index].calltime += timestamp;
4470}
4471
4472/* Allocate a return stack for each task */
4473static int start_graph_tracing(void)
4474{
4475	struct ftrace_ret_stack **ret_stack_list;
4476	int ret, cpu;
4477
4478	ret_stack_list = kmalloc(FTRACE_RETSTACK_ALLOC_SIZE *
4479				sizeof(struct ftrace_ret_stack *),
4480				GFP_KERNEL);
4481
4482	if (!ret_stack_list)
4483		return -ENOMEM;
4484
4485	/* The cpu_boot init_task->ret_stack will never be freed */
4486	for_each_online_cpu(cpu) {
4487		if (!idle_task(cpu)->ret_stack)
4488			ftrace_graph_init_idle_task(idle_task(cpu), cpu);
4489	}
4490
4491	do {
4492		ret = alloc_retstack_tasklist(ret_stack_list);
4493	} while (ret == -EAGAIN);
4494
4495	if (!ret) {
4496		ret = register_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4497		if (ret)
4498			pr_info("ftrace_graph: Couldn't activate tracepoint"
4499				" probe to kernel_sched_switch\n");
4500	}
4501
4502	kfree(ret_stack_list);
4503	return ret;
4504}
4505
4506/*
4507 * Hibernation protection.
4508 * The state of the current task is too much unstable during
4509 * suspend/restore to disk. We want to protect against that.
4510 */
4511static int
4512ftrace_suspend_notifier_call(struct notifier_block *bl, unsigned long state,
4513							void *unused)
4514{
4515	switch (state) {
4516	case PM_HIBERNATION_PREPARE:
4517		pause_graph_tracing();
4518		break;
4519
4520	case PM_POST_HIBERNATION:
4521		unpause_graph_tracing();
4522		break;
4523	}
4524	return NOTIFY_DONE;
4525}
4526
4527int register_ftrace_graph(trace_func_graph_ret_t retfunc,
4528			trace_func_graph_ent_t entryfunc)
4529{
4530	int ret = 0;
4531
4532	mutex_lock(&ftrace_lock);
4533
4534	/* we currently allow only one tracer registered at a time */
4535	if (ftrace_graph_active) {
4536		ret = -EBUSY;
4537		goto out;
4538	}
4539
4540	ftrace_suspend_notifier.notifier_call = ftrace_suspend_notifier_call;
4541	register_pm_notifier(&ftrace_suspend_notifier);
4542
4543	ftrace_graph_active++;
4544	ret = start_graph_tracing();
4545	if (ret) {
4546		ftrace_graph_active--;
4547		goto out;
4548	}
4549
4550	ftrace_graph_return = retfunc;
4551	ftrace_graph_entry = entryfunc;
4552
4553	ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET);
4554
4555out:
4556	mutex_unlock(&ftrace_lock);
4557	return ret;
4558}
4559
4560void unregister_ftrace_graph(void)
4561{
4562	mutex_lock(&ftrace_lock);
4563
4564	if (unlikely(!ftrace_graph_active))
4565		goto out;
4566
4567	ftrace_graph_active--;
4568	ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
4569	ftrace_graph_entry = ftrace_graph_entry_stub;
4570	ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET);
4571	unregister_pm_notifier(&ftrace_suspend_notifier);
4572	unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
4573
4574 out:
4575	mutex_unlock(&ftrace_lock);
4576}
4577
4578static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack);
4579
4580static void
4581graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack)
4582{
4583	atomic_set(&t->tracing_graph_pause, 0);
4584	atomic_set(&t->trace_overrun, 0);
4585	t->ftrace_timestamp = 0;
4586	/* make curr_ret_stack visible before we add the ret_stack */
4587	smp_wmb();
4588	t->ret_stack = ret_stack;
4589}
4590
4591/*
4592 * Allocate a return stack for the idle task. May be the first
4593 * time through, or it may be done by CPU hotplug online.
4594 */
4595void ftrace_graph_init_idle_task(struct task_struct *t, int cpu)
4596{
4597	t->curr_ret_stack = -1;
4598	/*
4599	 * The idle task has no parent, it either has its own
4600	 * stack or no stack at all.
4601	 */
4602	if (t->ret_stack)
4603		WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu));
4604
4605	if (ftrace_graph_active) {
4606		struct ftrace_ret_stack *ret_stack;
4607
4608		ret_stack = per_cpu(idle_ret_stack, cpu);
4609		if (!ret_stack) {
4610			ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4611					    * sizeof(struct ftrace_ret_stack),
4612					    GFP_KERNEL);
4613			if (!ret_stack)
4614				return;
4615			per_cpu(idle_ret_stack, cpu) = ret_stack;
4616		}
4617		graph_init_task(t, ret_stack);
4618	}
4619}
4620
4621/* Allocate a return stack for newly created task */
4622void ftrace_graph_init_task(struct task_struct *t)
4623{
4624	/* Make sure we do not use the parent ret_stack */
4625	t->ret_stack = NULL;
4626	t->curr_ret_stack = -1;
4627
4628	if (ftrace_graph_active) {
4629		struct ftrace_ret_stack *ret_stack;
4630
4631		ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
4632				* sizeof(struct ftrace_ret_stack),
4633				GFP_KERNEL);
4634		if (!ret_stack)
4635			return;
4636		graph_init_task(t, ret_stack);
4637	}
4638}
4639
4640void ftrace_graph_exit_task(struct task_struct *t)
4641{
4642	struct ftrace_ret_stack	*ret_stack = t->ret_stack;
4643
4644	t->ret_stack = NULL;
4645	/* NULL must become visible to IRQs before we free it: */
4646	barrier();
4647
4648	kfree(ret_stack);
4649}
4650
4651void ftrace_graph_stop(void)
4652{
4653	ftrace_stop();
4654}
4655#endif