1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Infrastructure for profiling code inserted by 'gcc -pg'.
   4 *
   5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
   6 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
   7 *
   8 * Originally ported from the -rt patch by:
   9 *   Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
  10 *
  11 * Based on code in the latency_tracer, that is:
  12 *
  13 *  Copyright (C) 2004-2006 Ingo Molnar
  14 *  Copyright (C) 2004 Nadia Yvette Chambers
  15 */
  16
  17#include <linux/stop_machine.h>
  18#include <linux/clocksource.h>
  19#include <linux/sched/task.h>
  20#include <linux/kallsyms.h>
  21#include <linux/security.h>
  22#include <linux/seq_file.h>
  23#include <linux/tracefs.h>
 
  24#include <linux/hardirq.h>
  25#include <linux/kthread.h>
  26#include <linux/uaccess.h>
  27#include <linux/bsearch.h>
  28#include <linux/module.h>
  29#include <linux/ftrace.h>
  30#include <linux/sysctl.h>
  31#include <linux/slab.h>
  32#include <linux/ctype.h>
  33#include <linux/sort.h>
  34#include <linux/list.h>
  35#include <linux/hash.h>
  36#include <linux/rcupdate.h>
  37#include <linux/kprobes.h>
  38
  39#include <trace/events/sched.h>
  40
  41#include <asm/sections.h>
  42#include <asm/setup.h>
  43
  44#include "ftrace_internal.h"
  45#include "trace_output.h"
  46#include "trace_stat.h"
  47
  48#define FTRACE_WARN_ON(cond)			\
  49	({					\
  50		int ___r = cond;		\
  51		if (WARN_ON(___r))		\
  52			ftrace_kill();		\
  53		___r;				\
  54	})
  55
  56#define FTRACE_WARN_ON_ONCE(cond)		\
  57	({					\
  58		int ___r = cond;		\
  59		if (WARN_ON_ONCE(___r))		\
  60			ftrace_kill();		\
  61		___r;				\
  62	})
  63
  64/* hash bits for specific function selection */
  65#define FTRACE_HASH_BITS 7
  66#define FTRACE_FUNC_HASHSIZE (1 << FTRACE_HASH_BITS)
  67#define FTRACE_HASH_DEFAULT_BITS 10
  68#define FTRACE_HASH_MAX_BITS 12
  69
 
 
  70#ifdef CONFIG_DYNAMIC_FTRACE
  71#define INIT_OPS_HASH(opsname)	\
  72	.func_hash		= &opsname.local_hash,			\
  73	.local_hash.regex_lock	= __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
  74#else
  75#define INIT_OPS_HASH(opsname)
  76#endif
  77
  78enum {
  79	FTRACE_MODIFY_ENABLE_FL		= (1 << 0),
  80	FTRACE_MODIFY_MAY_SLEEP_FL	= (1 << 1),
  81};
  82
  83struct ftrace_ops ftrace_list_end __read_mostly = {
  84	.func		= ftrace_stub,
  85	.flags		= FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_STUB,
  86	INIT_OPS_HASH(ftrace_list_end)
  87};
  88
  89/* ftrace_enabled is a method to turn ftrace on or off */
  90int ftrace_enabled __read_mostly;
  91static int last_ftrace_enabled;
  92
 
 
 
  93/* Current function tracing op */
  94struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
  95/* What to set function_trace_op to */
  96static struct ftrace_ops *set_function_trace_op;
  97
  98static bool ftrace_pids_enabled(struct ftrace_ops *ops)
  99{
 100	struct trace_array *tr;
 101
 102	if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
 103		return false;
 104
 105	tr = ops->private;
 106
 107	return tr->function_pids != NULL;
 108}
 109
 110static void ftrace_update_trampoline(struct ftrace_ops *ops);
 111
 112/*
 113 * ftrace_disabled is set when an anomaly is discovered.
 114 * ftrace_disabled is much stronger than ftrace_enabled.
 115 */
 116static int ftrace_disabled __read_mostly;
 117
 118DEFINE_MUTEX(ftrace_lock);
 119
 120struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
 
 
 121ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
 122struct ftrace_ops global_ops;
 
 
 123
 124#if ARCH_SUPPORTS_FTRACE_OPS
 125static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
 126				 struct ftrace_ops *op, struct pt_regs *regs);
 127#else
 128/* See comment below, where ftrace_ops_list_func is defined */
 129static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip);
 130#define ftrace_ops_list_func ((ftrace_func_t)ftrace_ops_no_ops)
 131#endif
 132
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 133static inline void ftrace_ops_init(struct ftrace_ops *ops)
 134{
 135#ifdef CONFIG_DYNAMIC_FTRACE
 136	if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
 137		mutex_init(&ops->local_hash.regex_lock);
 138		ops->func_hash = &ops->local_hash;
 139		ops->flags |= FTRACE_OPS_FL_INITIALIZED;
 140	}
 141#endif
 142}
 143
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 144static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
 145			    struct ftrace_ops *op, struct pt_regs *regs)
 146{
 147	struct trace_array *tr = op->private;
 148
 149	if (tr && this_cpu_read(tr->trace_buffer.data->ftrace_ignore_pid))
 150		return;
 151
 152	op->saved_func(ip, parent_ip, op, regs);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 153}
 154
 155static void ftrace_sync(struct work_struct *work)
 156{
 157	/*
 158	 * This function is just a stub to implement a hard force
 159	 * of synchronize_rcu(). This requires synchronizing
 160	 * tasks even in userspace and idle.
 161	 *
 162	 * Yes, function tracing is rude.
 163	 */
 164}
 165
 166static void ftrace_sync_ipi(void *data)
 167{
 168	/* Probably not needed, but do it anyway */
 169	smp_rmb();
 170}
 171
 172static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
 173{
 174	/*
 175	 * If this is a dynamic, RCU, or per CPU ops, or we force list func,
 176	 * then it needs to call the list anyway.
 177	 */
 178	if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
 179	    FTRACE_FORCE_LIST_FUNC)
 180		return ftrace_ops_list_func;
 181
 182	return ftrace_ops_get_func(ops);
 183}
 184
 185static void update_ftrace_function(void)
 186{
 187	ftrace_func_t func;
 188
 189	/*
 190	 * Prepare the ftrace_ops that the arch callback will use.
 191	 * If there's only one ftrace_ops registered, the ftrace_ops_list
 192	 * will point to the ops we want.
 193	 */
 194	set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
 195						lockdep_is_held(&ftrace_lock));
 196
 197	/* If there's no ftrace_ops registered, just call the stub function */
 198	if (set_function_trace_op == &ftrace_list_end) {
 199		func = ftrace_stub;
 200
 201	/*
 202	 * If we are at the end of the list and this ops is
 203	 * recursion safe and not dynamic and the arch supports passing ops,
 204	 * then have the mcount trampoline call the function directly.
 205	 */
 206	} else if (rcu_dereference_protected(ftrace_ops_list->next,
 207			lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
 208		func = ftrace_ops_get_list_func(ftrace_ops_list);
 209
 
 
 
 
 
 
 
 210	} else {
 211		/* Just use the default ftrace_ops */
 212		set_function_trace_op = &ftrace_list_end;
 213		func = ftrace_ops_list_func;
 214	}
 215
 216	update_function_graph_func();
 217
 218	/* If there's no change, then do nothing more here */
 219	if (ftrace_trace_function == func)
 220		return;
 221
 
 
 222	/*
 223	 * If we are using the list function, it doesn't care
 224	 * about the function_trace_ops.
 225	 */
 226	if (func == ftrace_ops_list_func) {
 227		ftrace_trace_function = func;
 228		/*
 229		 * Don't even bother setting function_trace_ops,
 230		 * it would be racy to do so anyway.
 231		 */
 232		return;
 233	}
 234
 235#ifndef CONFIG_DYNAMIC_FTRACE
 236	/*
 237	 * For static tracing, we need to be a bit more careful.
 238	 * The function change takes affect immediately. Thus,
 239	 * we need to coorditate the setting of the function_trace_ops
 240	 * with the setting of the ftrace_trace_function.
 241	 *
 242	 * Set the function to the list ops, which will call the
 243	 * function we want, albeit indirectly, but it handles the
 244	 * ftrace_ops and doesn't depend on function_trace_op.
 245	 */
 246	ftrace_trace_function = ftrace_ops_list_func;
 247	/*
 248	 * Make sure all CPUs see this. Yes this is slow, but static
 249	 * tracing is slow and nasty to have enabled.
 250	 */
 251	schedule_on_each_cpu(ftrace_sync);
 252	/* Now all cpus are using the list ops. */
 253	function_trace_op = set_function_trace_op;
 254	/* Make sure the function_trace_op is visible on all CPUs */
 255	smp_wmb();
 256	/* Nasty way to force a rmb on all cpus */
 257	smp_call_function(ftrace_sync_ipi, NULL, 1);
 258	/* OK, we are all set to update the ftrace_trace_function now! */
 259#endif /* !CONFIG_DYNAMIC_FTRACE */
 260
 261	ftrace_trace_function = func;
 262}
 263
 264static void add_ftrace_ops(struct ftrace_ops __rcu **list,
 265			   struct ftrace_ops *ops)
 266{
 267	rcu_assign_pointer(ops->next, *list);
 268
 269	/*
 270	 * We are entering ops into the list but another
 271	 * CPU might be walking that list. We need to make sure
 272	 * the ops->next pointer is valid before another CPU sees
 273	 * the ops pointer included into the list.
 274	 */
 275	rcu_assign_pointer(*list, ops);
 276}
 277
 278static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
 279			     struct ftrace_ops *ops)
 280{
 281	struct ftrace_ops **p;
 282
 283	/*
 284	 * If we are removing the last function, then simply point
 285	 * to the ftrace_stub.
 286	 */
 287	if (rcu_dereference_protected(*list,
 288			lockdep_is_held(&ftrace_lock)) == ops &&
 289	    rcu_dereference_protected(ops->next,
 290			lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
 291		*list = &ftrace_list_end;
 292		return 0;
 293	}
 294
 295	for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
 296		if (*p == ops)
 297			break;
 298
 299	if (*p != ops)
 300		return -1;
 301
 302	*p = (*p)->next;
 303	return 0;
 304}
 305
 306static void ftrace_update_trampoline(struct ftrace_ops *ops);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 307
 308int __register_ftrace_function(struct ftrace_ops *ops)
 309{
 310	if (ops->flags & FTRACE_OPS_FL_DELETED)
 311		return -EINVAL;
 312
 
 
 
 313	if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
 314		return -EBUSY;
 315
 
 
 
 
 316#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 317	/*
 318	 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
 319	 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
 320	 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
 321	 */
 322	if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
 323	    !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
 324		return -EINVAL;
 325
 326	if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
 327		ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
 328#endif
 329
 330	if (!core_kernel_data((unsigned long)ops))
 331		ops->flags |= FTRACE_OPS_FL_DYNAMIC;
 332
 333	add_ftrace_ops(&ftrace_ops_list, ops);
 334
 335	/* Always save the function, and reset at unregistering */
 336	ops->saved_func = ops->func;
 337
 338	if (ftrace_pids_enabled(ops))
 339		ops->func = ftrace_pid_func;
 340
 341	ftrace_update_trampoline(ops);
 342
 343	if (ftrace_enabled)
 344		update_ftrace_function();
 345
 346	return 0;
 347}
 348
 349int __unregister_ftrace_function(struct ftrace_ops *ops)
 350{
 351	int ret;
 352
 353	if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
 354		return -EBUSY;
 355
 356	ret = remove_ftrace_ops(&ftrace_ops_list, ops);
 
 
 
 
 
 
 
 
 
 
 
 
 357
 358	if (ret < 0)
 359		return ret;
 360
 361	if (ftrace_enabled)
 362		update_ftrace_function();
 363
 364	ops->func = ops->saved_func;
 365
 366	return 0;
 367}
 368
 369static void ftrace_update_pid_func(void)
 370{
 371	struct ftrace_ops *op;
 372
 373	/* Only do something if we are tracing something */
 374	if (ftrace_trace_function == ftrace_stub)
 375		return;
 376
 377	do_for_each_ftrace_op(op, ftrace_ops_list) {
 378		if (op->flags & FTRACE_OPS_FL_PID) {
 379			op->func = ftrace_pids_enabled(op) ?
 380				ftrace_pid_func : op->saved_func;
 381			ftrace_update_trampoline(op);
 382		}
 383	} while_for_each_ftrace_op(op);
 384
 385	update_ftrace_function();
 386}
 387
 388#ifdef CONFIG_FUNCTION_PROFILER
 389struct ftrace_profile {
 390	struct hlist_node		node;
 391	unsigned long			ip;
 392	unsigned long			counter;
 393#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 394	unsigned long long		time;
 395	unsigned long long		time_squared;
 396#endif
 397};
 398
 399struct ftrace_profile_page {
 400	struct ftrace_profile_page	*next;
 401	unsigned long			index;
 402	struct ftrace_profile		records[];
 403};
 404
 405struct ftrace_profile_stat {
 406	atomic_t			disabled;
 407	struct hlist_head		*hash;
 408	struct ftrace_profile_page	*pages;
 409	struct ftrace_profile_page	*start;
 410	struct tracer_stat		stat;
 411};
 412
 413#define PROFILE_RECORDS_SIZE						\
 414	(PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
 415
 416#define PROFILES_PER_PAGE					\
 417	(PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
 418
 419static int ftrace_profile_enabled __read_mostly;
 420
 421/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
 422static DEFINE_MUTEX(ftrace_profile_lock);
 423
 424static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
 425
 426#define FTRACE_PROFILE_HASH_BITS 10
 427#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
 428
 429static void *
 430function_stat_next(void *v, int idx)
 431{
 432	struct ftrace_profile *rec = v;
 433	struct ftrace_profile_page *pg;
 434
 435	pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
 436
 437 again:
 438	if (idx != 0)
 439		rec++;
 440
 441	if ((void *)rec >= (void *)&pg->records[pg->index]) {
 442		pg = pg->next;
 443		if (!pg)
 444			return NULL;
 445		rec = &pg->records[0];
 446		if (!rec->counter)
 447			goto again;
 448	}
 449
 450	return rec;
 451}
 452
 453static void *function_stat_start(struct tracer_stat *trace)
 454{
 455	struct ftrace_profile_stat *stat =
 456		container_of(trace, struct ftrace_profile_stat, stat);
 457
 458	if (!stat || !stat->start)
 459		return NULL;
 460
 461	return function_stat_next(&stat->start->records[0], 0);
 462}
 463
 464#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 465/* function graph compares on total time */
 466static int function_stat_cmp(void *p1, void *p2)
 467{
 468	struct ftrace_profile *a = p1;
 469	struct ftrace_profile *b = p2;
 470
 471	if (a->time < b->time)
 472		return -1;
 473	if (a->time > b->time)
 474		return 1;
 475	else
 476		return 0;
 477}
 478#else
 479/* not function graph compares against hits */
 480static int function_stat_cmp(void *p1, void *p2)
 481{
 482	struct ftrace_profile *a = p1;
 483	struct ftrace_profile *b = p2;
 484
 485	if (a->counter < b->counter)
 486		return -1;
 487	if (a->counter > b->counter)
 488		return 1;
 489	else
 490		return 0;
 491}
 492#endif
 493
 494static int function_stat_headers(struct seq_file *m)
 495{
 496#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 497	seq_puts(m, "  Function                               "
 498		 "Hit    Time            Avg             s^2\n"
 499		    "  --------                               "
 500		 "---    ----            ---             ---\n");
 501#else
 502	seq_puts(m, "  Function                               Hit\n"
 503		    "  --------                               ---\n");
 504#endif
 505	return 0;
 506}
 507
 508static int function_stat_show(struct seq_file *m, void *v)
 509{
 510	struct ftrace_profile *rec = v;
 511	char str[KSYM_SYMBOL_LEN];
 512	int ret = 0;
 513#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 514	static struct trace_seq s;
 515	unsigned long long avg;
 516	unsigned long long stddev;
 517#endif
 518	mutex_lock(&ftrace_profile_lock);
 519
 520	/* we raced with function_profile_reset() */
 521	if (unlikely(rec->counter == 0)) {
 522		ret = -EBUSY;
 523		goto out;
 524	}
 525
 526#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 527	avg = rec->time;
 528	do_div(avg, rec->counter);
 529	if (tracing_thresh && (avg < tracing_thresh))
 530		goto out;
 531#endif
 532
 533	kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 534	seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
 535
 536#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 537	seq_puts(m, "    ");
 
 
 538
 539	/* Sample standard deviation (s^2) */
 540	if (rec->counter <= 1)
 541		stddev = 0;
 542	else {
 543		/*
 544		 * Apply Welford's method:
 545		 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
 546		 */
 547		stddev = rec->counter * rec->time_squared -
 548			 rec->time * rec->time;
 549
 550		/*
 551		 * Divide only 1000 for ns^2 -> us^2 conversion.
 552		 * trace_print_graph_duration will divide 1000 again.
 553		 */
 554		do_div(stddev, rec->counter * (rec->counter - 1) * 1000);
 555	}
 556
 557	trace_seq_init(&s);
 558	trace_print_graph_duration(rec->time, &s);
 559	trace_seq_puts(&s, "    ");
 560	trace_print_graph_duration(avg, &s);
 561	trace_seq_puts(&s, "    ");
 562	trace_print_graph_duration(stddev, &s);
 563	trace_print_seq(m, &s);
 564#endif
 565	seq_putc(m, '\n');
 566out:
 567	mutex_unlock(&ftrace_profile_lock);
 568
 569	return ret;
 570}
 571
 572static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
 573{
 574	struct ftrace_profile_page *pg;
 575
 576	pg = stat->pages = stat->start;
 577
 578	while (pg) {
 579		memset(pg->records, 0, PROFILE_RECORDS_SIZE);
 580		pg->index = 0;
 581		pg = pg->next;
 582	}
 583
 584	memset(stat->hash, 0,
 585	       FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
 586}
 587
 588int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
 589{
 590	struct ftrace_profile_page *pg;
 591	int functions;
 592	int pages;
 593	int i;
 594
 595	/* If we already allocated, do nothing */
 596	if (stat->pages)
 597		return 0;
 598
 599	stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
 600	if (!stat->pages)
 601		return -ENOMEM;
 602
 603#ifdef CONFIG_DYNAMIC_FTRACE
 604	functions = ftrace_update_tot_cnt;
 605#else
 606	/*
 607	 * We do not know the number of functions that exist because
 608	 * dynamic tracing is what counts them. With past experience
 609	 * we have around 20K functions. That should be more than enough.
 610	 * It is highly unlikely we will execute every function in
 611	 * the kernel.
 612	 */
 613	functions = 20000;
 614#endif
 615
 616	pg = stat->start = stat->pages;
 617
 618	pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
 619
 620	for (i = 1; i < pages; i++) {
 621		pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 622		if (!pg->next)
 623			goto out_free;
 624		pg = pg->next;
 625	}
 626
 627	return 0;
 628
 629 out_free:
 630	pg = stat->start;
 631	while (pg) {
 632		unsigned long tmp = (unsigned long)pg;
 633
 634		pg = pg->next;
 635		free_page(tmp);
 636	}
 637
 638	stat->pages = NULL;
 639	stat->start = NULL;
 640
 641	return -ENOMEM;
 642}
 643
 644static int ftrace_profile_init_cpu(int cpu)
 645{
 646	struct ftrace_profile_stat *stat;
 647	int size;
 648
 649	stat = &per_cpu(ftrace_profile_stats, cpu);
 650
 651	if (stat->hash) {
 652		/* If the profile is already created, simply reset it */
 653		ftrace_profile_reset(stat);
 654		return 0;
 655	}
 656
 657	/*
 658	 * We are profiling all functions, but usually only a few thousand
 659	 * functions are hit. We'll make a hash of 1024 items.
 660	 */
 661	size = FTRACE_PROFILE_HASH_SIZE;
 662
 663	stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
 664
 665	if (!stat->hash)
 666		return -ENOMEM;
 667
 668	/* Preallocate the function profiling pages */
 669	if (ftrace_profile_pages_init(stat) < 0) {
 670		kfree(stat->hash);
 671		stat->hash = NULL;
 672		return -ENOMEM;
 673	}
 674
 675	return 0;
 676}
 677
 678static int ftrace_profile_init(void)
 679{
 680	int cpu;
 681	int ret = 0;
 682
 683	for_each_possible_cpu(cpu) {
 684		ret = ftrace_profile_init_cpu(cpu);
 685		if (ret)
 686			break;
 687	}
 688
 689	return ret;
 690}
 691
 692/* interrupts must be disabled */
 693static struct ftrace_profile *
 694ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
 695{
 696	struct ftrace_profile *rec;
 697	struct hlist_head *hhd;
 698	unsigned long key;
 699
 700	key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
 701	hhd = &stat->hash[key];
 702
 703	if (hlist_empty(hhd))
 704		return NULL;
 705
 706	hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
 707		if (rec->ip == ip)
 708			return rec;
 709	}
 710
 711	return NULL;
 712}
 713
 714static void ftrace_add_profile(struct ftrace_profile_stat *stat,
 715			       struct ftrace_profile *rec)
 716{
 717	unsigned long key;
 718
 719	key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
 720	hlist_add_head_rcu(&rec->node, &stat->hash[key]);
 721}
 722
 723/*
 724 * The memory is already allocated, this simply finds a new record to use.
 725 */
 726static struct ftrace_profile *
 727ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
 728{
 729	struct ftrace_profile *rec = NULL;
 730
 731	/* prevent recursion (from NMIs) */
 732	if (atomic_inc_return(&stat->disabled) != 1)
 733		goto out;
 734
 735	/*
 736	 * Try to find the function again since an NMI
 737	 * could have added it
 738	 */
 739	rec = ftrace_find_profiled_func(stat, ip);
 740	if (rec)
 741		goto out;
 742
 743	if (stat->pages->index == PROFILES_PER_PAGE) {
 744		if (!stat->pages->next)
 745			goto out;
 746		stat->pages = stat->pages->next;
 747	}
 748
 749	rec = &stat->pages->records[stat->pages->index++];
 750	rec->ip = ip;
 751	ftrace_add_profile(stat, rec);
 752
 753 out:
 754	atomic_dec(&stat->disabled);
 755
 756	return rec;
 757}
 758
 759static void
 760function_profile_call(unsigned long ip, unsigned long parent_ip,
 761		      struct ftrace_ops *ops, struct pt_regs *regs)
 762{
 763	struct ftrace_profile_stat *stat;
 764	struct ftrace_profile *rec;
 765	unsigned long flags;
 766
 767	if (!ftrace_profile_enabled)
 768		return;
 769
 770	local_irq_save(flags);
 771
 772	stat = this_cpu_ptr(&ftrace_profile_stats);
 773	if (!stat->hash || !ftrace_profile_enabled)
 774		goto out;
 775
 776	rec = ftrace_find_profiled_func(stat, ip);
 777	if (!rec) {
 778		rec = ftrace_profile_alloc(stat, ip);
 779		if (!rec)
 780			goto out;
 781	}
 782
 783	rec->counter++;
 784 out:
 785	local_irq_restore(flags);
 786}
 787
 788#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 789static bool fgraph_graph_time = true;
 790
 791void ftrace_graph_graph_time_control(bool enable)
 792{
 793	fgraph_graph_time = enable;
 794}
 795
 796static int profile_graph_entry(struct ftrace_graph_ent *trace)
 797{
 798	struct ftrace_ret_stack *ret_stack;
 799
 800	function_profile_call(trace->func, 0, NULL, NULL);
 801
 802	/* If function graph is shutting down, ret_stack can be NULL */
 803	if (!current->ret_stack)
 804		return 0;
 805
 806	ret_stack = ftrace_graph_get_ret_stack(current, 0);
 807	if (ret_stack)
 808		ret_stack->subtime = 0;
 809
 810	return 1;
 811}
 812
 813static void profile_graph_return(struct ftrace_graph_ret *trace)
 814{
 815	struct ftrace_ret_stack *ret_stack;
 816	struct ftrace_profile_stat *stat;
 817	unsigned long long calltime;
 818	struct ftrace_profile *rec;
 819	unsigned long flags;
 820
 821	local_irq_save(flags);
 822	stat = this_cpu_ptr(&ftrace_profile_stats);
 823	if (!stat->hash || !ftrace_profile_enabled)
 824		goto out;
 825
 826	/* If the calltime was zero'd ignore it */
 827	if (!trace->calltime)
 828		goto out;
 829
 830	calltime = trace->rettime - trace->calltime;
 831
 832	if (!fgraph_graph_time) {
 
 
 
 833
 834		/* Append this call time to the parent time to subtract */
 835		ret_stack = ftrace_graph_get_ret_stack(current, 1);
 836		if (ret_stack)
 837			ret_stack->subtime += calltime;
 838
 839		ret_stack = ftrace_graph_get_ret_stack(current, 0);
 840		if (ret_stack && ret_stack->subtime < calltime)
 841			calltime -= ret_stack->subtime;
 842		else
 843			calltime = 0;
 844	}
 845
 846	rec = ftrace_find_profiled_func(stat, trace->func);
 847	if (rec) {
 848		rec->time += calltime;
 849		rec->time_squared += calltime * calltime;
 850	}
 851
 852 out:
 853	local_irq_restore(flags);
 854}
 855
 856static struct fgraph_ops fprofiler_ops = {
 857	.entryfunc = &profile_graph_entry,
 858	.retfunc = &profile_graph_return,
 859};
 860
 861static int register_ftrace_profiler(void)
 862{
 863	return register_ftrace_graph(&fprofiler_ops);
 
 864}
 865
 866static void unregister_ftrace_profiler(void)
 867{
 868	unregister_ftrace_graph(&fprofiler_ops);
 869}
 870#else
 871static struct ftrace_ops ftrace_profile_ops __read_mostly = {
 872	.func		= function_profile_call,
 873	.flags		= FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_INITIALIZED,
 874	INIT_OPS_HASH(ftrace_profile_ops)
 875};
 876
 877static int register_ftrace_profiler(void)
 878{
 879	return register_ftrace_function(&ftrace_profile_ops);
 880}
 881
 882static void unregister_ftrace_profiler(void)
 883{
 884	unregister_ftrace_function(&ftrace_profile_ops);
 885}
 886#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 887
 888static ssize_t
 889ftrace_profile_write(struct file *filp, const char __user *ubuf,
 890		     size_t cnt, loff_t *ppos)
 891{
 892	unsigned long val;
 893	int ret;
 894
 895	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
 896	if (ret)
 897		return ret;
 898
 899	val = !!val;
 900
 901	mutex_lock(&ftrace_profile_lock);
 902	if (ftrace_profile_enabled ^ val) {
 903		if (val) {
 904			ret = ftrace_profile_init();
 905			if (ret < 0) {
 906				cnt = ret;
 907				goto out;
 908			}
 909
 910			ret = register_ftrace_profiler();
 911			if (ret < 0) {
 912				cnt = ret;
 913				goto out;
 914			}
 915			ftrace_profile_enabled = 1;
 916		} else {
 917			ftrace_profile_enabled = 0;
 918			/*
 919			 * unregister_ftrace_profiler calls stop_machine
 920			 * so this acts like an synchronize_rcu.
 921			 */
 922			unregister_ftrace_profiler();
 923		}
 924	}
 925 out:
 926	mutex_unlock(&ftrace_profile_lock);
 927
 928	*ppos += cnt;
 929
 930	return cnt;
 931}
 932
 933static ssize_t
 934ftrace_profile_read(struct file *filp, char __user *ubuf,
 935		     size_t cnt, loff_t *ppos)
 936{
 937	char buf[64];		/* big enough to hold a number */
 938	int r;
 939
 940	r = sprintf(buf, "%u\n", ftrace_profile_enabled);
 941	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 942}
 943
 944static const struct file_operations ftrace_profile_fops = {
 945	.open		= tracing_open_generic,
 946	.read		= ftrace_profile_read,
 947	.write		= ftrace_profile_write,
 948	.llseek		= default_llseek,
 949};
 950
 951/* used to initialize the real stat files */
 952static struct tracer_stat function_stats __initdata = {
 953	.name		= "functions",
 954	.stat_start	= function_stat_start,
 955	.stat_next	= function_stat_next,
 956	.stat_cmp	= function_stat_cmp,
 957	.stat_headers	= function_stat_headers,
 958	.stat_show	= function_stat_show
 959};
 960
 961static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
 962{
 963	struct ftrace_profile_stat *stat;
 964	struct dentry *entry;
 965	char *name;
 966	int ret;
 967	int cpu;
 968
 969	for_each_possible_cpu(cpu) {
 970		stat = &per_cpu(ftrace_profile_stats, cpu);
 971
 972		name = kasprintf(GFP_KERNEL, "function%d", cpu);
 
 973		if (!name) {
 974			/*
 975			 * The files created are permanent, if something happens
 976			 * we still do not free memory.
 977			 */
 978			WARN(1,
 979			     "Could not allocate stat file for cpu %d\n",
 980			     cpu);
 981			return;
 982		}
 983		stat->stat = function_stats;
 
 984		stat->stat.name = name;
 985		ret = register_stat_tracer(&stat->stat);
 986		if (ret) {
 987			WARN(1,
 988			     "Could not register function stat for cpu %d\n",
 989			     cpu);
 990			kfree(name);
 991			return;
 992		}
 993	}
 994
 995	entry = tracefs_create_file("function_profile_enabled", 0644,
 996				    d_tracer, NULL, &ftrace_profile_fops);
 997	if (!entry)
 998		pr_warn("Could not create tracefs 'function_profile_enabled' entry\n");
 
 999}
1000
1001#else /* CONFIG_FUNCTION_PROFILER */
1002static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1003{
1004}
1005#endif /* CONFIG_FUNCTION_PROFILER */
1006
1007#ifdef CONFIG_DYNAMIC_FTRACE
1008
1009static struct ftrace_ops *removed_ops;
1010
1011/*
1012 * Set when doing a global update, like enabling all recs or disabling them.
1013 * It is not set when just updating a single ftrace_ops.
1014 */
1015static bool update_all_ops;
1016
1017#ifndef CONFIG_FTRACE_MCOUNT_RECORD
1018# error Dynamic ftrace depends on MCOUNT_RECORD
1019#endif
1020
 
 
 
 
 
 
 
 
 
 
 
1021struct ftrace_func_entry {
1022	struct hlist_node hlist;
1023	unsigned long ip;
1024};
1025
1026struct ftrace_func_probe {
1027	struct ftrace_probe_ops	*probe_ops;
1028	struct ftrace_ops	ops;
1029	struct trace_array	*tr;
1030	struct list_head	list;
1031	void			*data;
1032	int			ref;
1033};
1034
1035/*
1036 * We make these constant because no one should touch them,
1037 * but they are used as the default "empty hash", to avoid allocating
1038 * it all the time. These are in a read only section such that if
1039 * anyone does try to modify it, it will cause an exception.
1040 */
1041static const struct hlist_head empty_buckets[1];
1042static const struct ftrace_hash empty_hash = {
1043	.buckets = (struct hlist_head *)empty_buckets,
1044};
1045#define EMPTY_HASH	((struct ftrace_hash *)&empty_hash)
1046
1047struct ftrace_ops global_ops = {
1048	.func				= ftrace_stub,
1049	.local_hash.notrace_hash	= EMPTY_HASH,
1050	.local_hash.filter_hash		= EMPTY_HASH,
1051	INIT_OPS_HASH(global_ops)
1052	.flags				= FTRACE_OPS_FL_RECURSION_SAFE |
1053					  FTRACE_OPS_FL_INITIALIZED |
1054					  FTRACE_OPS_FL_PID,
1055};
1056
1057/*
1058 * Used by the stack undwinder to know about dynamic ftrace trampolines.
1059 */
1060struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1061{
1062	struct ftrace_ops *op = NULL;
1063
1064	/*
1065	 * Some of the ops may be dynamically allocated,
1066	 * they are freed after a synchronize_rcu().
1067	 */
1068	preempt_disable_notrace();
1069
1070	do_for_each_ftrace_op(op, ftrace_ops_list) {
1071		/*
1072		 * This is to check for dynamically allocated trampolines.
1073		 * Trampolines that are in kernel text will have
1074		 * core_kernel_text() return true.
1075		 */
1076		if (op->trampoline && op->trampoline_size)
1077			if (addr >= op->trampoline &&
1078			    addr < op->trampoline + op->trampoline_size) {
1079				preempt_enable_notrace();
1080				return op;
1081			}
1082	} while_for_each_ftrace_op(op);
1083	preempt_enable_notrace();
1084
1085	return NULL;
1086}
1087
1088/*
1089 * This is used by __kernel_text_address() to return true if the
1090 * address is on a dynamically allocated trampoline that would
1091 * not return true for either core_kernel_text() or
1092 * is_module_text_address().
1093 */
1094bool is_ftrace_trampoline(unsigned long addr)
1095{
1096	return ftrace_ops_trampoline(addr) != NULL;
1097}
1098
1099struct ftrace_page {
1100	struct ftrace_page	*next;
1101	struct dyn_ftrace	*records;
1102	int			index;
1103	int			size;
1104};
1105
1106#define ENTRY_SIZE sizeof(struct dyn_ftrace)
1107#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1108
1109/* estimate from running different kernels */
1110#define NR_TO_INIT		10000
1111
1112static struct ftrace_page	*ftrace_pages_start;
1113static struct ftrace_page	*ftrace_pages;
1114
1115static __always_inline unsigned long
1116ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1117{
1118	if (hash->size_bits > 0)
1119		return hash_long(ip, hash->size_bits);
1120
1121	return 0;
1122}
1123
1124/* Only use this function if ftrace_hash_empty() has already been tested */
1125static __always_inline struct ftrace_func_entry *
1126__ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1127{
1128	unsigned long key;
1129	struct ftrace_func_entry *entry;
1130	struct hlist_head *hhd;
1131
1132	key = ftrace_hash_key(hash, ip);
 
 
 
 
 
 
 
1133	hhd = &hash->buckets[key];
1134
1135	hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1136		if (entry->ip == ip)
1137			return entry;
1138	}
1139	return NULL;
1140}
1141
1142/**
1143 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1144 * @hash: The hash to look at
1145 * @ip: The instruction pointer to test
1146 *
1147 * Search a given @hash to see if a given instruction pointer (@ip)
1148 * exists in it.
1149 *
1150 * Returns the entry that holds the @ip if found. NULL otherwise.
1151 */
1152struct ftrace_func_entry *
1153ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1154{
1155	if (ftrace_hash_empty(hash))
1156		return NULL;
1157
1158	return __ftrace_lookup_ip(hash, ip);
1159}
1160
1161static void __add_hash_entry(struct ftrace_hash *hash,
1162			     struct ftrace_func_entry *entry)
1163{
1164	struct hlist_head *hhd;
1165	unsigned long key;
1166
1167	key = ftrace_hash_key(hash, entry->ip);
 
 
 
 
1168	hhd = &hash->buckets[key];
1169	hlist_add_head(&entry->hlist, hhd);
1170	hash->count++;
1171}
1172
1173static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1174{
1175	struct ftrace_func_entry *entry;
1176
1177	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1178	if (!entry)
1179		return -ENOMEM;
1180
1181	entry->ip = ip;
1182	__add_hash_entry(hash, entry);
1183
1184	return 0;
1185}
1186
1187static void
1188free_hash_entry(struct ftrace_hash *hash,
1189		  struct ftrace_func_entry *entry)
1190{
1191	hlist_del(&entry->hlist);
1192	kfree(entry);
1193	hash->count--;
1194}
1195
1196static void
1197remove_hash_entry(struct ftrace_hash *hash,
1198		  struct ftrace_func_entry *entry)
1199{
1200	hlist_del_rcu(&entry->hlist);
1201	hash->count--;
1202}
1203
1204static void ftrace_hash_clear(struct ftrace_hash *hash)
1205{
1206	struct hlist_head *hhd;
1207	struct hlist_node *tn;
1208	struct ftrace_func_entry *entry;
1209	int size = 1 << hash->size_bits;
1210	int i;
1211
1212	if (!hash->count)
1213		return;
1214
1215	for (i = 0; i < size; i++) {
1216		hhd = &hash->buckets[i];
1217		hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1218			free_hash_entry(hash, entry);
1219	}
1220	FTRACE_WARN_ON(hash->count);
1221}
1222
1223static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1224{
1225	list_del(&ftrace_mod->list);
1226	kfree(ftrace_mod->module);
1227	kfree(ftrace_mod->func);
1228	kfree(ftrace_mod);
1229}
1230
1231static void clear_ftrace_mod_list(struct list_head *head)
1232{
1233	struct ftrace_mod_load *p, *n;
1234
1235	/* stack tracer isn't supported yet */
1236	if (!head)
1237		return;
1238
1239	mutex_lock(&ftrace_lock);
1240	list_for_each_entry_safe(p, n, head, list)
1241		free_ftrace_mod(p);
1242	mutex_unlock(&ftrace_lock);
1243}
1244
1245static void free_ftrace_hash(struct ftrace_hash *hash)
1246{
1247	if (!hash || hash == EMPTY_HASH)
1248		return;
1249	ftrace_hash_clear(hash);
1250	kfree(hash->buckets);
1251	kfree(hash);
1252}
1253
1254static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1255{
1256	struct ftrace_hash *hash;
1257
1258	hash = container_of(rcu, struct ftrace_hash, rcu);
1259	free_ftrace_hash(hash);
1260}
1261
1262static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1263{
1264	if (!hash || hash == EMPTY_HASH)
1265		return;
1266	call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1267}
1268
1269void ftrace_free_filter(struct ftrace_ops *ops)
1270{
1271	ftrace_ops_init(ops);
1272	free_ftrace_hash(ops->func_hash->filter_hash);
1273	free_ftrace_hash(ops->func_hash->notrace_hash);
1274}
1275
1276static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1277{
1278	struct ftrace_hash *hash;
1279	int size;
1280
1281	hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1282	if (!hash)
1283		return NULL;
1284
1285	size = 1 << size_bits;
1286	hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1287
1288	if (!hash->buckets) {
1289		kfree(hash);
1290		return NULL;
1291	}
1292
1293	hash->size_bits = size_bits;
1294
1295	return hash;
1296}
1297
1298
1299static int ftrace_add_mod(struct trace_array *tr,
1300			  const char *func, const char *module,
1301			  int enable)
1302{
1303	struct ftrace_mod_load *ftrace_mod;
1304	struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1305
1306	ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1307	if (!ftrace_mod)
1308		return -ENOMEM;
1309
1310	ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1311	ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1312	ftrace_mod->enable = enable;
1313
1314	if (!ftrace_mod->func || !ftrace_mod->module)
1315		goto out_free;
1316
1317	list_add(&ftrace_mod->list, mod_head);
1318
1319	return 0;
1320
1321 out_free:
1322	free_ftrace_mod(ftrace_mod);
1323
1324	return -ENOMEM;
1325}
1326
1327static struct ftrace_hash *
1328alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1329{
1330	struct ftrace_func_entry *entry;
1331	struct ftrace_hash *new_hash;
1332	int size;
1333	int ret;
1334	int i;
1335
1336	new_hash = alloc_ftrace_hash(size_bits);
1337	if (!new_hash)
1338		return NULL;
1339
1340	if (hash)
1341		new_hash->flags = hash->flags;
1342
1343	/* Empty hash? */
1344	if (ftrace_hash_empty(hash))
1345		return new_hash;
1346
1347	size = 1 << hash->size_bits;
1348	for (i = 0; i < size; i++) {
1349		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1350			ret = add_hash_entry(new_hash, entry->ip);
1351			if (ret < 0)
1352				goto free_hash;
1353		}
1354	}
1355
1356	FTRACE_WARN_ON(new_hash->count != hash->count);
1357
1358	return new_hash;
1359
1360 free_hash:
1361	free_ftrace_hash(new_hash);
1362	return NULL;
1363}
1364
1365static void
1366ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1367static void
1368ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1369
1370static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1371				       struct ftrace_hash *new_hash);
1372
1373static struct ftrace_hash *
1374__ftrace_hash_move(struct ftrace_hash *src)
1375{
1376	struct ftrace_func_entry *entry;
1377	struct hlist_node *tn;
1378	struct hlist_head *hhd;
 
1379	struct ftrace_hash *new_hash;
1380	int size = src->count;
1381	int bits = 0;
 
1382	int i;
1383
1384	/*
1385	 * If the new source is empty, just return the empty_hash.
 
1386	 */
1387	if (ftrace_hash_empty(src))
1388		return EMPTY_HASH;
 
 
 
 
 
 
 
 
 
 
 
1389
1390	/*
1391	 * Make the hash size about 1/2 the # found
1392	 */
1393	for (size /= 2; size; size >>= 1)
1394		bits++;
1395
1396	/* Don't allocate too much */
1397	if (bits > FTRACE_HASH_MAX_BITS)
1398		bits = FTRACE_HASH_MAX_BITS;
1399
 
1400	new_hash = alloc_ftrace_hash(bits);
1401	if (!new_hash)
1402		return NULL;
1403
1404	new_hash->flags = src->flags;
1405
1406	size = 1 << src->size_bits;
1407	for (i = 0; i < size; i++) {
1408		hhd = &src->buckets[i];
1409		hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1410			remove_hash_entry(src, entry);
1411			__add_hash_entry(new_hash, entry);
1412		}
1413	}
1414
1415	return new_hash;
1416}
1417
1418static int
1419ftrace_hash_move(struct ftrace_ops *ops, int enable,
1420		 struct ftrace_hash **dst, struct ftrace_hash *src)
1421{
1422	struct ftrace_hash *new_hash;
1423	int ret;
1424
1425	/* Reject setting notrace hash on IPMODIFY ftrace_ops */
1426	if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1427		return -EINVAL;
1428
1429	new_hash = __ftrace_hash_move(src);
1430	if (!new_hash)
1431		return -ENOMEM;
1432
1433	/* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1434	if (enable) {
1435		/* IPMODIFY should be updated only when filter_hash updating */
1436		ret = ftrace_hash_ipmodify_update(ops, new_hash);
1437		if (ret < 0) {
1438			free_ftrace_hash(new_hash);
1439			return ret;
1440		}
1441	}
1442
 
 
1443	/*
1444	 * Remove the current set, update the hash and add
1445	 * them back.
 
1446	 */
1447	ftrace_hash_rec_disable_modify(ops, enable);
1448
1449	rcu_assign_pointer(*dst, new_hash);
1450
1451	ftrace_hash_rec_enable_modify(ops, enable);
1452
1453	return 0;
1454}
1455
1456static bool hash_contains_ip(unsigned long ip,
1457			     struct ftrace_ops_hash *hash)
1458{
1459	/*
1460	 * The function record is a match if it exists in the filter
1461	 * hash and not in the notrace hash. Note, an emty hash is
1462	 * considered a match for the filter hash, but an empty
1463	 * notrace hash is considered not in the notrace hash.
1464	 */
1465	return (ftrace_hash_empty(hash->filter_hash) ||
1466		__ftrace_lookup_ip(hash->filter_hash, ip)) &&
1467		(ftrace_hash_empty(hash->notrace_hash) ||
1468		 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1469}
1470
1471/*
1472 * Test the hashes for this ops to see if we want to call
1473 * the ops->func or not.
1474 *
1475 * It's a match if the ip is in the ops->filter_hash or
1476 * the filter_hash does not exist or is empty,
1477 *  AND
1478 * the ip is not in the ops->notrace_hash.
1479 *
1480 * This needs to be called with preemption disabled as
1481 * the hashes are freed with call_rcu().
1482 */
1483int
1484ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1485{
1486	struct ftrace_ops_hash hash;
 
1487	int ret;
1488
1489#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1490	/*
1491	 * There's a small race when adding ops that the ftrace handler
1492	 * that wants regs, may be called without them. We can not
1493	 * allow that handler to be called if regs is NULL.
1494	 */
1495	if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1496		return 0;
1497#endif
1498
1499	rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1500	rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1501
1502	if (hash_contains_ip(ip, &hash))
 
 
 
1503		ret = 1;
1504	else
1505		ret = 0;
1506
1507	return ret;
1508}
1509
1510/*
1511 * This is a double for. Do not use 'break' to break out of the loop,
1512 * you must use a goto.
1513 */
1514#define do_for_each_ftrace_rec(pg, rec)					\
1515	for (pg = ftrace_pages_start; pg; pg = pg->next) {		\
1516		int _____i;						\
1517		for (_____i = 0; _____i < pg->index; _____i++) {	\
1518			rec = &pg->records[_____i];
1519
1520#define while_for_each_ftrace_rec()		\
1521		}				\
1522	}
1523
1524
1525static int ftrace_cmp_recs(const void *a, const void *b)
1526{
1527	const struct dyn_ftrace *key = a;
1528	const struct dyn_ftrace *rec = b;
1529
1530	if (key->flags < rec->ip)
1531		return -1;
1532	if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1533		return 1;
1534	return 0;
1535}
1536
1537/**
1538 * ftrace_location_range - return the first address of a traced location
1539 *	if it touches the given ip range
1540 * @start: start of range to search.
1541 * @end: end of range to search (inclusive). @end points to the last byte
1542 *	to check.
1543 *
1544 * Returns rec->ip if the related ftrace location is a least partly within
1545 * the given address range. That is, the first address of the instruction
1546 * that is either a NOP or call to the function tracer. It checks the ftrace
1547 * internal tables to determine if the address belongs or not.
1548 */
1549unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1550{
1551	struct ftrace_page *pg;
1552	struct dyn_ftrace *rec;
1553	struct dyn_ftrace key;
1554
1555	key.ip = start;
1556	key.flags = end;	/* overload flags, as it is unsigned long */
1557
1558	for (pg = ftrace_pages_start; pg; pg = pg->next) {
1559		if (end < pg->records[0].ip ||
1560		    start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1561			continue;
1562		rec = bsearch(&key, pg->records, pg->index,
1563			      sizeof(struct dyn_ftrace),
1564			      ftrace_cmp_recs);
1565		if (rec)
1566			return rec->ip;
1567	}
1568
1569	return 0;
1570}
1571
1572/**
1573 * ftrace_location - return true if the ip giving is a traced location
1574 * @ip: the instruction pointer to check
1575 *
1576 * Returns rec->ip if @ip given is a pointer to a ftrace location.
1577 * That is, the instruction that is either a NOP or call to
1578 * the function tracer. It checks the ftrace internal tables to
1579 * determine if the address belongs or not.
1580 */
1581unsigned long ftrace_location(unsigned long ip)
1582{
1583	return ftrace_location_range(ip, ip);
1584}
1585
1586/**
1587 * ftrace_text_reserved - return true if range contains an ftrace location
1588 * @start: start of range to search
1589 * @end: end of range to search (inclusive). @end points to the last byte to check.
1590 *
1591 * Returns 1 if @start and @end contains a ftrace location.
1592 * That is, the instruction that is either a NOP or call to
1593 * the function tracer. It checks the ftrace internal tables to
1594 * determine if the address belongs or not.
1595 */
1596int ftrace_text_reserved(const void *start, const void *end)
1597{
1598	unsigned long ret;
1599
1600	ret = ftrace_location_range((unsigned long)start,
1601				    (unsigned long)end);
1602
1603	return (int)!!ret;
1604}
1605
1606/* Test if ops registered to this rec needs regs */
1607static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1608{
1609	struct ftrace_ops *ops;
1610	bool keep_regs = false;
1611
1612	for (ops = ftrace_ops_list;
1613	     ops != &ftrace_list_end; ops = ops->next) {
1614		/* pass rec in as regs to have non-NULL val */
1615		if (ftrace_ops_test(ops, rec->ip, rec)) {
1616			if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1617				keep_regs = true;
1618				break;
1619			}
1620		}
1621	}
1622
1623	return  keep_regs;
1624}
1625
1626static struct ftrace_ops *
1627ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1628static struct ftrace_ops *
1629ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1630
1631static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1632				     int filter_hash,
1633				     bool inc)
1634{
1635	struct ftrace_hash *hash;
1636	struct ftrace_hash *other_hash;
1637	struct ftrace_page *pg;
1638	struct dyn_ftrace *rec;
1639	bool update = false;
1640	int count = 0;
1641	int all = false;
1642
1643	/* Only update if the ops has been registered */
1644	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1645		return false;
1646
1647	/*
1648	 * In the filter_hash case:
1649	 *   If the count is zero, we update all records.
1650	 *   Otherwise we just update the items in the hash.
1651	 *
1652	 * In the notrace_hash case:
1653	 *   We enable the update in the hash.
1654	 *   As disabling notrace means enabling the tracing,
1655	 *   and enabling notrace means disabling, the inc variable
1656	 *   gets inversed.
1657	 */
1658	if (filter_hash) {
1659		hash = ops->func_hash->filter_hash;
1660		other_hash = ops->func_hash->notrace_hash;
1661		if (ftrace_hash_empty(hash))
1662			all = true;
1663	} else {
1664		inc = !inc;
1665		hash = ops->func_hash->notrace_hash;
1666		other_hash = ops->func_hash->filter_hash;
1667		/*
1668		 * If the notrace hash has no items,
1669		 * then there's nothing to do.
1670		 */
1671		if (ftrace_hash_empty(hash))
1672			return false;
1673	}
1674
1675	do_for_each_ftrace_rec(pg, rec) {
1676		int in_other_hash = 0;
1677		int in_hash = 0;
1678		int match = 0;
1679
1680		if (rec->flags & FTRACE_FL_DISABLED)
1681			continue;
1682
1683		if (all) {
1684			/*
1685			 * Only the filter_hash affects all records.
1686			 * Update if the record is not in the notrace hash.
1687			 */
1688			if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1689				match = 1;
1690		} else {
1691			in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1692			in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1693
1694			/*
1695			 * If filter_hash is set, we want to match all functions
1696			 * that are in the hash but not in the other hash.
1697			 *
1698			 * If filter_hash is not set, then we are decrementing.
1699			 * That means we match anything that is in the hash
1700			 * and also in the other_hash. That is, we need to turn
1701			 * off functions in the other hash because they are disabled
1702			 * by this hash.
1703			 */
1704			if (filter_hash && in_hash && !in_other_hash)
1705				match = 1;
1706			else if (!filter_hash && in_hash &&
1707				 (in_other_hash || ftrace_hash_empty(other_hash)))
1708				match = 1;
1709		}
1710		if (!match)
1711			continue;
1712
1713		if (inc) {
1714			rec->flags++;
1715			if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1716				return false;
1717
1718			/*
1719			 * If there's only a single callback registered to a
1720			 * function, and the ops has a trampoline registered
1721			 * for it, then we can call it directly.
1722			 */
1723			if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1724				rec->flags |= FTRACE_FL_TRAMP;
1725			else
1726				/*
1727				 * If we are adding another function callback
1728				 * to this function, and the previous had a
1729				 * custom trampoline in use, then we need to go
1730				 * back to the default trampoline.
1731				 */
1732				rec->flags &= ~FTRACE_FL_TRAMP;
1733
1734			/*
1735			 * If any ops wants regs saved for this function
1736			 * then all ops will get saved regs.
1737			 */
1738			if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1739				rec->flags |= FTRACE_FL_REGS;
1740		} else {
1741			if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1742				return false;
1743			rec->flags--;
1744
1745			/*
1746			 * If the rec had REGS enabled and the ops that is
1747			 * being removed had REGS set, then see if there is
1748			 * still any ops for this record that wants regs.
1749			 * If not, we can stop recording them.
1750			 */
1751			if (ftrace_rec_count(rec) > 0 &&
1752			    rec->flags & FTRACE_FL_REGS &&
1753			    ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1754				if (!test_rec_ops_needs_regs(rec))
1755					rec->flags &= ~FTRACE_FL_REGS;
1756			}
1757
1758			/*
1759			 * The TRAMP needs to be set only if rec count
1760			 * is decremented to one, and the ops that is
1761			 * left has a trampoline. As TRAMP can only be
1762			 * enabled if there is only a single ops attached
1763			 * to it.
1764			 */
1765			if (ftrace_rec_count(rec) == 1 &&
1766			    ftrace_find_tramp_ops_any(rec))
1767				rec->flags |= FTRACE_FL_TRAMP;
1768			else
1769				rec->flags &= ~FTRACE_FL_TRAMP;
1770
1771			/*
1772			 * flags will be cleared in ftrace_check_record()
1773			 * if rec count is zero.
1774			 */
1775		}
1776		count++;
1777
1778		/* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1779		update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1780
1781		/* Shortcut, if we handled all records, we are done. */
1782		if (!all && count == hash->count)
1783			return update;
1784	} while_for_each_ftrace_rec();
1785
1786	return update;
1787}
1788
1789static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1790				    int filter_hash)
1791{
1792	return __ftrace_hash_rec_update(ops, filter_hash, 0);
1793}
1794
1795static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1796				   int filter_hash)
1797{
1798	return __ftrace_hash_rec_update(ops, filter_hash, 1);
1799}
1800
1801static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1802					  int filter_hash, int inc)
1803{
1804	struct ftrace_ops *op;
1805
1806	__ftrace_hash_rec_update(ops, filter_hash, inc);
1807
1808	if (ops->func_hash != &global_ops.local_hash)
1809		return;
1810
1811	/*
1812	 * If the ops shares the global_ops hash, then we need to update
1813	 * all ops that are enabled and use this hash.
1814	 */
1815	do_for_each_ftrace_op(op, ftrace_ops_list) {
1816		/* Already done */
1817		if (op == ops)
1818			continue;
1819		if (op->func_hash == &global_ops.local_hash)
1820			__ftrace_hash_rec_update(op, filter_hash, inc);
1821	} while_for_each_ftrace_op(op);
1822}
1823
1824static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1825					   int filter_hash)
1826{
1827	ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1828}
1829
1830static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1831					  int filter_hash)
1832{
1833	ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1834}
1835
1836/*
1837 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1838 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1839 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1840 * Note that old_hash and new_hash has below meanings
1841 *  - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1842 *  - If the hash is EMPTY_HASH, it hits nothing
1843 *  - Anything else hits the recs which match the hash entries.
1844 */
1845static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1846					 struct ftrace_hash *old_hash,
1847					 struct ftrace_hash *new_hash)
1848{
1849	struct ftrace_page *pg;
1850	struct dyn_ftrace *rec, *end = NULL;
1851	int in_old, in_new;
1852
1853	/* Only update if the ops has been registered */
1854	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1855		return 0;
1856
1857	if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
1858		return 0;
1859
1860	/*
1861	 * Since the IPMODIFY is a very address sensitive action, we do not
1862	 * allow ftrace_ops to set all functions to new hash.
1863	 */
1864	if (!new_hash || !old_hash)
1865		return -EINVAL;
1866
1867	/* Update rec->flags */
1868	do_for_each_ftrace_rec(pg, rec) {
1869
1870		if (rec->flags & FTRACE_FL_DISABLED)
1871			continue;
1872
1873		/* We need to update only differences of filter_hash */
1874		in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1875		in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1876		if (in_old == in_new)
1877			continue;
1878
1879		if (in_new) {
1880			/* New entries must ensure no others are using it */
1881			if (rec->flags & FTRACE_FL_IPMODIFY)
1882				goto rollback;
1883			rec->flags |= FTRACE_FL_IPMODIFY;
1884		} else /* Removed entry */
1885			rec->flags &= ~FTRACE_FL_IPMODIFY;
1886	} while_for_each_ftrace_rec();
1887
1888	return 0;
1889
1890rollback:
1891	end = rec;
1892
1893	/* Roll back what we did above */
1894	do_for_each_ftrace_rec(pg, rec) {
1895
1896		if (rec->flags & FTRACE_FL_DISABLED)
1897			continue;
1898
1899		if (rec == end)
1900			goto err_out;
1901
1902		in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1903		in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1904		if (in_old == in_new)
1905			continue;
1906
1907		if (in_new)
1908			rec->flags &= ~FTRACE_FL_IPMODIFY;
1909		else
1910			rec->flags |= FTRACE_FL_IPMODIFY;
1911	} while_for_each_ftrace_rec();
1912
1913err_out:
1914	return -EBUSY;
1915}
1916
1917static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
1918{
1919	struct ftrace_hash *hash = ops->func_hash->filter_hash;
1920
1921	if (ftrace_hash_empty(hash))
1922		hash = NULL;
1923
1924	return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
1925}
1926
1927/* Disabling always succeeds */
1928static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
1929{
1930	struct ftrace_hash *hash = ops->func_hash->filter_hash;
1931
1932	if (ftrace_hash_empty(hash))
1933		hash = NULL;
1934
1935	__ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
1936}
1937
1938static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1939				       struct ftrace_hash *new_hash)
1940{
1941	struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
1942
1943	if (ftrace_hash_empty(old_hash))
1944		old_hash = NULL;
1945
1946	if (ftrace_hash_empty(new_hash))
1947		new_hash = NULL;
1948
1949	return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
1950}
1951
1952static void print_ip_ins(const char *fmt, const unsigned char *p)
1953{
1954	int i;
1955
1956	printk(KERN_CONT "%s", fmt);
1957
1958	for (i = 0; i < MCOUNT_INSN_SIZE; i++)
1959		printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]);
1960}
1961
1962enum ftrace_bug_type ftrace_bug_type;
1963const void *ftrace_expected;
1964
1965static void print_bug_type(void)
1966{
1967	switch (ftrace_bug_type) {
1968	case FTRACE_BUG_UNKNOWN:
1969		break;
1970	case FTRACE_BUG_INIT:
1971		pr_info("Initializing ftrace call sites\n");
1972		break;
1973	case FTRACE_BUG_NOP:
1974		pr_info("Setting ftrace call site to NOP\n");
1975		break;
1976	case FTRACE_BUG_CALL:
1977		pr_info("Setting ftrace call site to call ftrace function\n");
1978		break;
1979	case FTRACE_BUG_UPDATE:
1980		pr_info("Updating ftrace call site to call a different ftrace function\n");
1981		break;
1982	}
1983}
1984
1985/**
1986 * ftrace_bug - report and shutdown function tracer
1987 * @failed: The failed type (EFAULT, EINVAL, EPERM)
1988 * @rec: The record that failed
1989 *
1990 * The arch code that enables or disables the function tracing
1991 * can call ftrace_bug() when it has detected a problem in
1992 * modifying the code. @failed should be one of either:
1993 * EFAULT - if the problem happens on reading the @ip address
1994 * EINVAL - if what is read at @ip is not what was expected
1995 * EPERM - if the problem happens on writing to the @ip address
1996 */
1997void ftrace_bug(int failed, struct dyn_ftrace *rec)
1998{
1999	unsigned long ip = rec ? rec->ip : 0;
2000
2001	switch (failed) {
2002	case -EFAULT:
2003		FTRACE_WARN_ON_ONCE(1);
2004		pr_info("ftrace faulted on modifying ");
2005		print_ip_sym(ip);
2006		break;
2007	case -EINVAL:
2008		FTRACE_WARN_ON_ONCE(1);
2009		pr_info("ftrace failed to modify ");
2010		print_ip_sym(ip);
2011		print_ip_ins(" actual:   ", (unsigned char *)ip);
2012		pr_cont("\n");
2013		if (ftrace_expected) {
2014			print_ip_ins(" expected: ", ftrace_expected);
2015			pr_cont("\n");
2016		}
2017		break;
2018	case -EPERM:
2019		FTRACE_WARN_ON_ONCE(1);
2020		pr_info("ftrace faulted on writing ");
2021		print_ip_sym(ip);
2022		break;
2023	default:
2024		FTRACE_WARN_ON_ONCE(1);
2025		pr_info("ftrace faulted on unknown error ");
2026		print_ip_sym(ip);
2027	}
2028	print_bug_type();
2029	if (rec) {
2030		struct ftrace_ops *ops = NULL;
2031
2032		pr_info("ftrace record flags: %lx\n", rec->flags);
2033		pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2034			rec->flags & FTRACE_FL_REGS ? " R" : "  ");
2035		if (rec->flags & FTRACE_FL_TRAMP_EN) {
2036			ops = ftrace_find_tramp_ops_any(rec);
2037			if (ops) {
2038				do {
2039					pr_cont("\ttramp: %pS (%pS)",
2040						(void *)ops->trampoline,
2041						(void *)ops->func);
2042					ops = ftrace_find_tramp_ops_next(rec, ops);
2043				} while (ops);
2044			} else
2045				pr_cont("\ttramp: ERROR!");
2046
2047		}
2048		ip = ftrace_get_addr_curr(rec);
2049		pr_cont("\n expected tramp: %lx\n", ip);
2050	}
2051}
2052
2053static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2054{
2055	unsigned long flag = 0UL;
2056
2057	ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2058
2059	if (rec->flags & FTRACE_FL_DISABLED)
2060		return FTRACE_UPDATE_IGNORE;
2061
2062	/*
2063	 * If we are updating calls:
2064	 *
2065	 *   If the record has a ref count, then we need to enable it
2066	 *   because someone is using it.
2067	 *
2068	 *   Otherwise we make sure its disabled.
2069	 *
2070	 * If we are disabling calls, then disable all records that
2071	 * are enabled.
2072	 */
2073	if (enable && ftrace_rec_count(rec))
2074		flag = FTRACE_FL_ENABLED;
2075
2076	/*
2077	 * If enabling and the REGS flag does not match the REGS_EN, or
2078	 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2079	 * this record. Set flags to fail the compare against ENABLED.
2080	 */
2081	if (flag) {
2082		if (!(rec->flags & FTRACE_FL_REGS) != 
2083		    !(rec->flags & FTRACE_FL_REGS_EN))
2084			flag |= FTRACE_FL_REGS;
2085
2086		if (!(rec->flags & FTRACE_FL_TRAMP) != 
2087		    !(rec->flags & FTRACE_FL_TRAMP_EN))
2088			flag |= FTRACE_FL_TRAMP;
2089	}
2090
2091	/* If the state of this record hasn't changed, then do nothing */
2092	if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2093		return FTRACE_UPDATE_IGNORE;
2094
2095	if (flag) {
2096		/* Save off if rec is being enabled (for return value) */
2097		flag ^= rec->flags & FTRACE_FL_ENABLED;
2098
2099		if (update) {
2100			rec->flags |= FTRACE_FL_ENABLED;
2101			if (flag & FTRACE_FL_REGS) {
2102				if (rec->flags & FTRACE_FL_REGS)
2103					rec->flags |= FTRACE_FL_REGS_EN;
2104				else
2105					rec->flags &= ~FTRACE_FL_REGS_EN;
2106			}
2107			if (flag & FTRACE_FL_TRAMP) {
2108				if (rec->flags & FTRACE_FL_TRAMP)
2109					rec->flags |= FTRACE_FL_TRAMP_EN;
2110				else
2111					rec->flags &= ~FTRACE_FL_TRAMP_EN;
2112			}
2113		}
2114
2115		/*
2116		 * If this record is being updated from a nop, then
2117		 *   return UPDATE_MAKE_CALL.
 
 
 
2118		 * Otherwise,
2119		 *   return UPDATE_MODIFY_CALL to tell the caller to convert
2120		 *   from the save regs, to a non-save regs function or
2121		 *   vice versa, or from a trampoline call.
2122		 */
2123		if (flag & FTRACE_FL_ENABLED) {
2124			ftrace_bug_type = FTRACE_BUG_CALL;
2125			return FTRACE_UPDATE_MAKE_CALL;
2126		}
2127
2128		ftrace_bug_type = FTRACE_BUG_UPDATE;
2129		return FTRACE_UPDATE_MODIFY_CALL;
2130	}
2131
2132	if (update) {
2133		/* If there's no more users, clear all flags */
2134		if (!ftrace_rec_count(rec))
2135			rec->flags = 0;
2136		else
2137			/*
2138			 * Just disable the record, but keep the ops TRAMP
2139			 * and REGS states. The _EN flags must be disabled though.
2140			 */
2141			rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2142					FTRACE_FL_REGS_EN);
2143	}
2144
2145	ftrace_bug_type = FTRACE_BUG_NOP;
2146	return FTRACE_UPDATE_MAKE_NOP;
2147}
2148
2149/**
2150 * ftrace_update_record, set a record that now is tracing or not
2151 * @rec: the record to update
2152 * @enable: set to true if the record is tracing, false to force disable
2153 *
2154 * The records that represent all functions that can be traced need
2155 * to be updated when tracing has been enabled.
2156 */
2157int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2158{
2159	return ftrace_check_record(rec, enable, true);
2160}
2161
2162/**
2163 * ftrace_test_record, check if the record has been enabled or not
2164 * @rec: the record to test
2165 * @enable: set to true to check if enabled, false if it is disabled
2166 *
2167 * The arch code may need to test if a record is already set to
2168 * tracing to determine how to modify the function code that it
2169 * represents.
2170 */
2171int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2172{
2173	return ftrace_check_record(rec, enable, false);
2174}
2175
2176static struct ftrace_ops *
2177ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2178{
2179	struct ftrace_ops *op;
2180	unsigned long ip = rec->ip;
2181
2182	do_for_each_ftrace_op(op, ftrace_ops_list) {
2183
2184		if (!op->trampoline)
2185			continue;
2186
2187		if (hash_contains_ip(ip, op->func_hash))
2188			return op;
2189	} while_for_each_ftrace_op(op);
2190
2191	return NULL;
2192}
2193
2194static struct ftrace_ops *
2195ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2196			   struct ftrace_ops *op)
2197{
2198	unsigned long ip = rec->ip;
2199
2200	while_for_each_ftrace_op(op) {
2201
2202		if (!op->trampoline)
2203			continue;
2204
2205		if (hash_contains_ip(ip, op->func_hash))
2206			return op;
2207	} 
2208
2209	return NULL;
2210}
2211
2212static struct ftrace_ops *
2213ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2214{
2215	struct ftrace_ops *op;
2216	unsigned long ip = rec->ip;
2217
2218	/*
2219	 * Need to check removed ops first.
2220	 * If they are being removed, and this rec has a tramp,
2221	 * and this rec is in the ops list, then it would be the
2222	 * one with the tramp.
2223	 */
2224	if (removed_ops) {
2225		if (hash_contains_ip(ip, &removed_ops->old_hash))
2226			return removed_ops;
2227	}
2228
2229	/*
2230	 * Need to find the current trampoline for a rec.
2231	 * Now, a trampoline is only attached to a rec if there
2232	 * was a single 'ops' attached to it. But this can be called
2233	 * when we are adding another op to the rec or removing the
2234	 * current one. Thus, if the op is being added, we can
2235	 * ignore it because it hasn't attached itself to the rec
2236	 * yet.
2237	 *
2238	 * If an ops is being modified (hooking to different functions)
2239	 * then we don't care about the new functions that are being
2240	 * added, just the old ones (that are probably being removed).
2241	 *
2242	 * If we are adding an ops to a function that already is using
2243	 * a trampoline, it needs to be removed (trampolines are only
2244	 * for single ops connected), then an ops that is not being
2245	 * modified also needs to be checked.
2246	 */
2247	do_for_each_ftrace_op(op, ftrace_ops_list) {
2248
2249		if (!op->trampoline)
2250			continue;
2251
2252		/*
2253		 * If the ops is being added, it hasn't gotten to
2254		 * the point to be removed from this tree yet.
2255		 */
2256		if (op->flags & FTRACE_OPS_FL_ADDING)
2257			continue;
2258
2259
2260		/*
2261		 * If the ops is being modified and is in the old
2262		 * hash, then it is probably being removed from this
2263		 * function.
2264		 */
2265		if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2266		    hash_contains_ip(ip, &op->old_hash))
2267			return op;
2268		/*
2269		 * If the ops is not being added or modified, and it's
2270		 * in its normal filter hash, then this must be the one
2271		 * we want!
2272		 */
2273		if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2274		    hash_contains_ip(ip, op->func_hash))
2275			return op;
2276
2277	} while_for_each_ftrace_op(op);
2278
2279	return NULL;
2280}
2281
2282static struct ftrace_ops *
2283ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2284{
2285	struct ftrace_ops *op;
2286	unsigned long ip = rec->ip;
2287
2288	do_for_each_ftrace_op(op, ftrace_ops_list) {
2289		/* pass rec in as regs to have non-NULL val */
2290		if (hash_contains_ip(ip, op->func_hash))
2291			return op;
2292	} while_for_each_ftrace_op(op);
2293
2294	return NULL;
2295}
2296
2297/**
2298 * ftrace_get_addr_new - Get the call address to set to
2299 * @rec:  The ftrace record descriptor
2300 *
2301 * If the record has the FTRACE_FL_REGS set, that means that it
2302 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2303 * is not not set, then it wants to convert to the normal callback.
2304 *
2305 * Returns the address of the trampoline to set to
2306 */
2307unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2308{
2309	struct ftrace_ops *ops;
2310
2311	/* Trampolines take precedence over regs */
2312	if (rec->flags & FTRACE_FL_TRAMP) {
2313		ops = ftrace_find_tramp_ops_new(rec);
2314		if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2315			pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2316				(void *)rec->ip, (void *)rec->ip, rec->flags);
2317			/* Ftrace is shutting down, return anything */
2318			return (unsigned long)FTRACE_ADDR;
2319		}
2320		return ops->trampoline;
2321	}
2322
2323	if (rec->flags & FTRACE_FL_REGS)
2324		return (unsigned long)FTRACE_REGS_ADDR;
2325	else
2326		return (unsigned long)FTRACE_ADDR;
2327}
2328
2329/**
2330 * ftrace_get_addr_curr - Get the call address that is already there
2331 * @rec:  The ftrace record descriptor
2332 *
2333 * The FTRACE_FL_REGS_EN is set when the record already points to
2334 * a function that saves all the regs. Basically the '_EN' version
2335 * represents the current state of the function.
2336 *
2337 * Returns the address of the trampoline that is currently being called
2338 */
2339unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2340{
2341	struct ftrace_ops *ops;
2342
2343	/* Trampolines take precedence over regs */
2344	if (rec->flags & FTRACE_FL_TRAMP_EN) {
2345		ops = ftrace_find_tramp_ops_curr(rec);
2346		if (FTRACE_WARN_ON(!ops)) {
2347			pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2348				(void *)rec->ip, (void *)rec->ip);
2349			/* Ftrace is shutting down, return anything */
2350			return (unsigned long)FTRACE_ADDR;
2351		}
2352		return ops->trampoline;
2353	}
2354
2355	if (rec->flags & FTRACE_FL_REGS_EN)
2356		return (unsigned long)FTRACE_REGS_ADDR;
2357	else
2358		return (unsigned long)FTRACE_ADDR;
2359}
2360
2361static int
2362__ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2363{
2364	unsigned long ftrace_old_addr;
2365	unsigned long ftrace_addr;
2366	int ret;
2367
2368	ftrace_addr = ftrace_get_addr_new(rec);
2369
2370	/* This needs to be done before we call ftrace_update_record */
2371	ftrace_old_addr = ftrace_get_addr_curr(rec);
2372
2373	ret = ftrace_update_record(rec, enable);
2374
2375	ftrace_bug_type = FTRACE_BUG_UNKNOWN;
 
 
 
2376
2377	switch (ret) {
2378	case FTRACE_UPDATE_IGNORE:
2379		return 0;
2380
2381	case FTRACE_UPDATE_MAKE_CALL:
2382		ftrace_bug_type = FTRACE_BUG_CALL;
2383		return ftrace_make_call(rec, ftrace_addr);
2384
2385	case FTRACE_UPDATE_MAKE_NOP:
2386		ftrace_bug_type = FTRACE_BUG_NOP;
2387		return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2388
 
2389	case FTRACE_UPDATE_MODIFY_CALL:
2390		ftrace_bug_type = FTRACE_BUG_UPDATE;
 
 
 
 
2391		return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2392	}
2393
2394	return -1; /* unknown ftrace bug */
2395}
2396
2397void __weak ftrace_replace_code(int mod_flags)
2398{
2399	struct dyn_ftrace *rec;
2400	struct ftrace_page *pg;
2401	bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2402	int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2403	int failed;
2404
2405	if (unlikely(ftrace_disabled))
2406		return;
2407
2408	do_for_each_ftrace_rec(pg, rec) {
2409
2410		if (rec->flags & FTRACE_FL_DISABLED)
2411			continue;
2412
2413		failed = __ftrace_replace_code(rec, enable);
2414		if (failed) {
2415			ftrace_bug(failed, rec);
2416			/* Stop processing */
2417			return;
2418		}
2419		if (schedulable)
2420			cond_resched();
2421	} while_for_each_ftrace_rec();
2422}
2423
2424struct ftrace_rec_iter {
2425	struct ftrace_page	*pg;
2426	int			index;
2427};
2428
2429/**
2430 * ftrace_rec_iter_start, start up iterating over traced functions
2431 *
2432 * Returns an iterator handle that is used to iterate over all
2433 * the records that represent address locations where functions
2434 * are traced.
2435 *
2436 * May return NULL if no records are available.
2437 */
2438struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2439{
2440	/*
2441	 * We only use a single iterator.
2442	 * Protected by the ftrace_lock mutex.
2443	 */
2444	static struct ftrace_rec_iter ftrace_rec_iter;
2445	struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2446
2447	iter->pg = ftrace_pages_start;
2448	iter->index = 0;
2449
2450	/* Could have empty pages */
2451	while (iter->pg && !iter->pg->index)
2452		iter->pg = iter->pg->next;
2453
2454	if (!iter->pg)
2455		return NULL;
2456
2457	return iter;
2458}
2459
2460/**
2461 * ftrace_rec_iter_next, get the next record to process.
2462 * @iter: The handle to the iterator.
2463 *
2464 * Returns the next iterator after the given iterator @iter.
2465 */
2466struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2467{
2468	iter->index++;
2469
2470	if (iter->index >= iter->pg->index) {
2471		iter->pg = iter->pg->next;
2472		iter->index = 0;
2473
2474		/* Could have empty pages */
2475		while (iter->pg && !iter->pg->index)
2476			iter->pg = iter->pg->next;
2477	}
2478
2479	if (!iter->pg)
2480		return NULL;
2481
2482	return iter;
2483}
2484
2485/**
2486 * ftrace_rec_iter_record, get the record at the iterator location
2487 * @iter: The current iterator location
2488 *
2489 * Returns the record that the current @iter is at.
2490 */
2491struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2492{
2493	return &iter->pg->records[iter->index];
2494}
2495
2496static int
2497ftrace_code_disable(struct module *mod, struct dyn_ftrace *rec)
2498{
 
2499	int ret;
2500
 
 
2501	if (unlikely(ftrace_disabled))
2502		return 0;
2503
2504	ret = ftrace_make_nop(mod, rec, MCOUNT_ADDR);
2505	if (ret) {
2506		ftrace_bug_type = FTRACE_BUG_INIT;
2507		ftrace_bug(ret, rec);
2508		return 0;
2509	}
2510	return 1;
2511}
2512
2513/*
2514 * archs can override this function if they must do something
2515 * before the modifying code is performed.
2516 */
2517int __weak ftrace_arch_code_modify_prepare(void)
2518{
2519	return 0;
2520}
2521
2522/*
2523 * archs can override this function if they must do something
2524 * after the modifying code is performed.
2525 */
2526int __weak ftrace_arch_code_modify_post_process(void)
2527{
2528	return 0;
2529}
2530
2531void ftrace_modify_all_code(int command)
2532{
2533	int update = command & FTRACE_UPDATE_TRACE_FUNC;
2534	int mod_flags = 0;
2535	int err = 0;
2536
2537	if (command & FTRACE_MAY_SLEEP)
2538		mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2539
2540	/*
2541	 * If the ftrace_caller calls a ftrace_ops func directly,
2542	 * we need to make sure that it only traces functions it
2543	 * expects to trace. When doing the switch of functions,
2544	 * we need to update to the ftrace_ops_list_func first
2545	 * before the transition between old and new calls are set,
2546	 * as the ftrace_ops_list_func will check the ops hashes
2547	 * to make sure the ops are having the right functions
2548	 * traced.
2549	 */
2550	if (update) {
2551		err = ftrace_update_ftrace_func(ftrace_ops_list_func);
2552		if (FTRACE_WARN_ON(err))
2553			return;
2554	}
2555
2556	if (command & FTRACE_UPDATE_CALLS)
2557		ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2558	else if (command & FTRACE_DISABLE_CALLS)
2559		ftrace_replace_code(mod_flags);
2560
2561	if (update && ftrace_trace_function != ftrace_ops_list_func) {
2562		function_trace_op = set_function_trace_op;
2563		smp_wmb();
2564		/* If irqs are disabled, we are in stop machine */
2565		if (!irqs_disabled())
2566			smp_call_function(ftrace_sync_ipi, NULL, 1);
2567		err = ftrace_update_ftrace_func(ftrace_trace_function);
2568		if (FTRACE_WARN_ON(err))
2569			return;
2570	}
2571
2572	if (command & FTRACE_START_FUNC_RET)
2573		err = ftrace_enable_ftrace_graph_caller();
2574	else if (command & FTRACE_STOP_FUNC_RET)
2575		err = ftrace_disable_ftrace_graph_caller();
2576	FTRACE_WARN_ON(err);
2577}
2578
2579static int __ftrace_modify_code(void *data)
2580{
2581	int *command = data;
2582
2583	ftrace_modify_all_code(*command);
2584
2585	return 0;
2586}
2587
2588/**
2589 * ftrace_run_stop_machine, go back to the stop machine method
2590 * @command: The command to tell ftrace what to do
2591 *
2592 * If an arch needs to fall back to the stop machine method, the
2593 * it can call this function.
2594 */
2595void ftrace_run_stop_machine(int command)
2596{
2597	stop_machine(__ftrace_modify_code, &command, NULL);
2598}
2599
2600/**
2601 * arch_ftrace_update_code, modify the code to trace or not trace
2602 * @command: The command that needs to be done
2603 *
2604 * Archs can override this function if it does not need to
2605 * run stop_machine() to modify code.
2606 */
2607void __weak arch_ftrace_update_code(int command)
2608{
2609	ftrace_run_stop_machine(command);
2610}
2611
2612static void ftrace_run_update_code(int command)
2613{
2614	int ret;
2615
2616	ret = ftrace_arch_code_modify_prepare();
2617	FTRACE_WARN_ON(ret);
2618	if (ret)
2619		return;
 
 
 
 
 
2620
2621	/*
2622	 * By default we use stop_machine() to modify the code.
2623	 * But archs can do what ever they want as long as it
2624	 * is safe. The stop_machine() is the safest, but also
2625	 * produces the most overhead.
2626	 */
2627	arch_ftrace_update_code(command);
2628
 
 
2629	ret = ftrace_arch_code_modify_post_process();
2630	FTRACE_WARN_ON(ret);
2631}
2632
2633static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2634				   struct ftrace_ops_hash *old_hash)
2635{
2636	ops->flags |= FTRACE_OPS_FL_MODIFYING;
2637	ops->old_hash.filter_hash = old_hash->filter_hash;
2638	ops->old_hash.notrace_hash = old_hash->notrace_hash;
2639	ftrace_run_update_code(command);
2640	ops->old_hash.filter_hash = NULL;
2641	ops->old_hash.notrace_hash = NULL;
2642	ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2643}
2644
2645static ftrace_func_t saved_ftrace_func;
2646static int ftrace_start_up;
 
2647
2648void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2649{
 
2650}
2651
2652static void ftrace_startup_enable(int command)
2653{
2654	if (saved_ftrace_func != ftrace_trace_function) {
2655		saved_ftrace_func = ftrace_trace_function;
2656		command |= FTRACE_UPDATE_TRACE_FUNC;
2657	}
2658
2659	if (!command || !ftrace_enabled)
2660		return;
2661
2662	ftrace_run_update_code(command);
2663}
2664
2665static void ftrace_startup_all(int command)
2666{
2667	update_all_ops = true;
2668	ftrace_startup_enable(command);
2669	update_all_ops = false;
2670}
2671
2672int ftrace_startup(struct ftrace_ops *ops, int command)
2673{
 
2674	int ret;
2675
2676	if (unlikely(ftrace_disabled))
2677		return -ENODEV;
2678
2679	ret = __register_ftrace_function(ops);
2680	if (ret)
2681		return ret;
2682
2683	ftrace_start_up++;
 
2684
2685	/*
2686	 * Note that ftrace probes uses this to start up
2687	 * and modify functions it will probe. But we still
2688	 * set the ADDING flag for modification, as probes
2689	 * do not have trampolines. If they add them in the
2690	 * future, then the probes will need to distinguish
2691	 * between adding and updating probes.
2692	 */
2693	ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2694
2695	ret = ftrace_hash_ipmodify_enable(ops);
2696	if (ret < 0) {
2697		/* Rollback registration process */
2698		__unregister_ftrace_function(ops);
2699		ftrace_start_up--;
2700		ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2701		return ret;
2702	}
2703
2704	if (ftrace_hash_rec_enable(ops, 1))
2705		command |= FTRACE_UPDATE_CALLS;
 
2706
2707	ftrace_startup_enable(command);
2708
2709	ops->flags &= ~FTRACE_OPS_FL_ADDING;
2710
2711	return 0;
2712}
2713
2714int ftrace_shutdown(struct ftrace_ops *ops, int command)
2715{
 
2716	int ret;
2717
2718	if (unlikely(ftrace_disabled))
2719		return -ENODEV;
2720
2721	ret = __unregister_ftrace_function(ops);
2722	if (ret)
2723		return ret;
2724
2725	ftrace_start_up--;
2726	/*
2727	 * Just warn in case of unbalance, no need to kill ftrace, it's not
2728	 * critical but the ftrace_call callers may be never nopped again after
2729	 * further ftrace uses.
2730	 */
2731	WARN_ON_ONCE(ftrace_start_up < 0);
2732
2733	/* Disabling ipmodify never fails */
2734	ftrace_hash_ipmodify_disable(ops);
 
 
 
 
 
 
 
 
2735
2736	if (ftrace_hash_rec_disable(ops, 1))
2737		command |= FTRACE_UPDATE_CALLS;
2738
2739	ops->flags &= ~FTRACE_OPS_FL_ENABLED;
 
 
 
2740
2741	if (saved_ftrace_func != ftrace_trace_function) {
2742		saved_ftrace_func = ftrace_trace_function;
2743		command |= FTRACE_UPDATE_TRACE_FUNC;
2744	}
2745
2746	if (!command || !ftrace_enabled) {
2747		/*
2748		 * If these are dynamic or per_cpu ops, they still
2749		 * need their data freed. Since, function tracing is
2750		 * not currently active, we can just free them
2751		 * without synchronizing all CPUs.
2752		 */
2753		if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2754			goto free_ops;
2755
2756		return 0;
2757	}
2758
2759	/*
2760	 * If the ops uses a trampoline, then it needs to be
2761	 * tested first on update.
2762	 */
2763	ops->flags |= FTRACE_OPS_FL_REMOVING;
2764	removed_ops = ops;
2765
2766	/* The trampoline logic checks the old hashes */
2767	ops->old_hash.filter_hash = ops->func_hash->filter_hash;
2768	ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
2769
2770	ftrace_run_update_code(command);
2771
2772	/*
2773	 * If there's no more ops registered with ftrace, run a
2774	 * sanity check to make sure all rec flags are cleared.
2775	 */
2776	if (rcu_dereference_protected(ftrace_ops_list,
2777			lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
2778		struct ftrace_page *pg;
2779		struct dyn_ftrace *rec;
2780
2781		do_for_each_ftrace_rec(pg, rec) {
2782			if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
2783				pr_warn("  %pS flags:%lx\n",
2784					(void *)rec->ip, rec->flags);
2785		} while_for_each_ftrace_rec();
2786	}
2787
2788	ops->old_hash.filter_hash = NULL;
2789	ops->old_hash.notrace_hash = NULL;
2790
2791	removed_ops = NULL;
2792	ops->flags &= ~FTRACE_OPS_FL_REMOVING;
2793
2794	/*
2795	 * Dynamic ops may be freed, we must make sure that all
2796	 * callers are done before leaving this function.
2797	 * The same goes for freeing the per_cpu data of the per_cpu
2798	 * ops.
 
 
 
 
 
 
 
 
2799	 */
2800	if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
2801		/*
2802		 * We need to do a hard force of sched synchronization.
2803		 * This is because we use preempt_disable() to do RCU, but
2804		 * the function tracers can be called where RCU is not watching
2805		 * (like before user_exit()). We can not rely on the RCU
2806		 * infrastructure to do the synchronization, thus we must do it
2807		 * ourselves.
2808		 */
2809		schedule_on_each_cpu(ftrace_sync);
2810
2811		/*
2812		 * When the kernel is preeptive, tasks can be preempted
2813		 * while on a ftrace trampoline. Just scheduling a task on
2814		 * a CPU is not good enough to flush them. Calling
2815		 * synchornize_rcu_tasks() will wait for those tasks to
2816		 * execute and either schedule voluntarily or enter user space.
2817		 */
2818		if (IS_ENABLED(CONFIG_PREEMPTION))
2819			synchronize_rcu_tasks();
2820
2821 free_ops:
2822		arch_ftrace_trampoline_free(ops);
2823	}
2824
2825	return 0;
2826}
2827
2828static void ftrace_startup_sysctl(void)
2829{
2830	int command;
2831
2832	if (unlikely(ftrace_disabled))
2833		return;
2834
2835	/* Force update next time */
2836	saved_ftrace_func = NULL;
2837	/* ftrace_start_up is true if we want ftrace running */
2838	if (ftrace_start_up) {
2839		command = FTRACE_UPDATE_CALLS;
2840		if (ftrace_graph_active)
2841			command |= FTRACE_START_FUNC_RET;
2842		ftrace_startup_enable(command);
2843	}
2844}
2845
2846static void ftrace_shutdown_sysctl(void)
2847{
2848	int command;
2849
2850	if (unlikely(ftrace_disabled))
2851		return;
2852
2853	/* ftrace_start_up is true if ftrace is running */
2854	if (ftrace_start_up) {
2855		command = FTRACE_DISABLE_CALLS;
2856		if (ftrace_graph_active)
2857			command |= FTRACE_STOP_FUNC_RET;
2858		ftrace_run_update_code(command);
2859	}
2860}
2861
2862static u64		ftrace_update_time;
2863unsigned long		ftrace_update_tot_cnt;
2864
2865static inline int ops_traces_mod(struct ftrace_ops *ops)
2866{
2867	/*
2868	 * Filter_hash being empty will default to trace module.
2869	 * But notrace hash requires a test of individual module functions.
2870	 */
2871	return ftrace_hash_empty(ops->func_hash->filter_hash) &&
2872		ftrace_hash_empty(ops->func_hash->notrace_hash);
2873}
2874
2875/*
2876 * Check if the current ops references the record.
2877 *
2878 * If the ops traces all functions, then it was already accounted for.
2879 * If the ops does not trace the current record function, skip it.
2880 * If the ops ignores the function via notrace filter, skip it.
2881 */
2882static inline bool
2883ops_references_rec(struct ftrace_ops *ops, struct dyn_ftrace *rec)
2884{
2885	/* If ops isn't enabled, ignore it */
2886	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
2887		return false;
2888
2889	/* If ops traces all then it includes this function */
2890	if (ops_traces_mod(ops))
2891		return true;
2892
2893	/* The function must be in the filter */
2894	if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
2895	    !__ftrace_lookup_ip(ops->func_hash->filter_hash, rec->ip))
2896		return false;
2897
2898	/* If in notrace hash, we ignore it too */
2899	if (ftrace_lookup_ip(ops->func_hash->notrace_hash, rec->ip))
2900		return false;
 
 
 
2901
2902	return true;
 
 
 
 
 
 
 
 
 
 
2903}
2904
2905static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
2906{
2907	struct ftrace_page *pg;
2908	struct dyn_ftrace *p;
2909	u64 start, stop;
2910	unsigned long update_cnt = 0;
2911	unsigned long rec_flags = 0;
 
2912	int i;
2913
2914	start = ftrace_now(raw_smp_processor_id());
2915
2916	/*
2917	 * When a module is loaded, this function is called to convert
2918	 * the calls to mcount in its text to nops, and also to create
2919	 * an entry in the ftrace data. Now, if ftrace is activated
2920	 * after this call, but before the module sets its text to
2921	 * read-only, the modification of enabling ftrace can fail if
2922	 * the read-only is done while ftrace is converting the calls.
2923	 * To prevent this, the module's records are set as disabled
2924	 * and will be enabled after the call to set the module's text
2925	 * to read-only.
2926	 */
2927	if (mod)
2928		rec_flags |= FTRACE_FL_DISABLED;
 
 
 
 
 
 
 
 
 
 
 
 
 
2929
2930	for (pg = new_pgs; pg; pg = pg->next) {
2931
2932		for (i = 0; i < pg->index; i++) {
 
2933
2934			/* If something went wrong, bail without enabling anything */
2935			if (unlikely(ftrace_disabled))
2936				return -1;
2937
2938			p = &pg->records[i];
2939			p->flags = rec_flags;
 
 
2940
2941			/*
2942			 * Do the initial record conversion from mcount jump
2943			 * to the NOP instructions.
2944			 */
2945			if (!__is_defined(CC_USING_NOP_MCOUNT) &&
2946			    !ftrace_code_disable(mod, p))
2947				break;
2948
2949			update_cnt++;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2950		}
2951	}
2952
2953	stop = ftrace_now(raw_smp_processor_id());
2954	ftrace_update_time = stop - start;
2955	ftrace_update_tot_cnt += update_cnt;
2956
2957	return 0;
2958}
2959
2960static int ftrace_allocate_records(struct ftrace_page *pg, int count)
2961{
2962	int order;
2963	int cnt;
2964
2965	if (WARN_ON(!count))
2966		return -EINVAL;
2967
2968	order = get_count_order(DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
2969
2970	/*
2971	 * We want to fill as much as possible. No more than a page
2972	 * may be empty.
2973	 */
2974	while ((PAGE_SIZE << order) / ENTRY_SIZE >= count + ENTRIES_PER_PAGE)
2975		order--;
2976
2977 again:
2978	pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
2979
2980	if (!pg->records) {
2981		/* if we can't allocate this size, try something smaller */
2982		if (!order)
2983			return -ENOMEM;
2984		order >>= 1;
2985		goto again;
2986	}
2987
2988	cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
2989	pg->size = cnt;
2990
2991	if (cnt > count)
2992		cnt = count;
2993
2994	return cnt;
2995}
2996
2997static struct ftrace_page *
2998ftrace_allocate_pages(unsigned long num_to_init)
2999{
3000	struct ftrace_page *start_pg;
3001	struct ftrace_page *pg;
3002	int order;
3003	int cnt;
3004
3005	if (!num_to_init)
3006		return NULL;
3007
3008	start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3009	if (!pg)
3010		return NULL;
3011
3012	/*
3013	 * Try to allocate as much as possible in one continues
3014	 * location that fills in all of the space. We want to
3015	 * waste as little space as possible.
3016	 */
3017	for (;;) {
3018		cnt = ftrace_allocate_records(pg, num_to_init);
3019		if (cnt < 0)
3020			goto free_pages;
3021
3022		num_to_init -= cnt;
3023		if (!num_to_init)
3024			break;
3025
3026		pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3027		if (!pg->next)
3028			goto free_pages;
3029
3030		pg = pg->next;
3031	}
3032
3033	return start_pg;
3034
3035 free_pages:
3036	pg = start_pg;
3037	while (pg) {
3038		order = get_count_order(pg->size / ENTRIES_PER_PAGE);
3039		free_pages((unsigned long)pg->records, order);
3040		start_pg = pg->next;
3041		kfree(pg);
3042		pg = start_pg;
3043	}
3044	pr_info("ftrace: FAILED to allocate memory for functions\n");
3045	return NULL;
3046}
3047
3048#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3049
3050struct ftrace_iterator {
3051	loff_t				pos;
3052	loff_t				func_pos;
3053	loff_t				mod_pos;
3054	struct ftrace_page		*pg;
3055	struct dyn_ftrace		*func;
3056	struct ftrace_func_probe	*probe;
3057	struct ftrace_func_entry	*probe_entry;
3058	struct trace_parser		parser;
3059	struct ftrace_hash		*hash;
3060	struct ftrace_ops		*ops;
3061	struct trace_array		*tr;
3062	struct list_head		*mod_list;
3063	int				pidx;
3064	int				idx;
3065	unsigned			flags;
3066};
3067
3068static void *
3069t_probe_next(struct seq_file *m, loff_t *pos)
3070{
3071	struct ftrace_iterator *iter = m->private;
3072	struct trace_array *tr = iter->ops->private;
3073	struct list_head *func_probes;
3074	struct ftrace_hash *hash;
3075	struct list_head *next;
3076	struct hlist_node *hnd = NULL;
3077	struct hlist_head *hhd;
3078	int size;
3079
3080	(*pos)++;
3081	iter->pos = *pos;
3082
3083	if (!tr)
3084		return NULL;
3085
3086	func_probes = &tr->func_probes;
3087	if (list_empty(func_probes))
3088		return NULL;
3089
3090	if (!iter->probe) {
3091		next = func_probes->next;
3092		iter->probe = list_entry(next, struct ftrace_func_probe, list);
3093	}
3094
3095	if (iter->probe_entry)
3096		hnd = &iter->probe_entry->hlist;
3097
3098	hash = iter->probe->ops.func_hash->filter_hash;
3099
3100	/*
3101	 * A probe being registered may temporarily have an empty hash
3102	 * and it's at the end of the func_probes list.
3103	 */
3104	if (!hash || hash == EMPTY_HASH)
3105		return NULL;
3106
3107	size = 1 << hash->size_bits;
3108
3109 retry:
3110	if (iter->pidx >= size) {
3111		if (iter->probe->list.next == func_probes)
3112			return NULL;
3113		next = iter->probe->list.next;
3114		iter->probe = list_entry(next, struct ftrace_func_probe, list);
3115		hash = iter->probe->ops.func_hash->filter_hash;
3116		size = 1 << hash->size_bits;
3117		iter->pidx = 0;
3118	}
3119
3120	hhd = &hash->buckets[iter->pidx];
3121
3122	if (hlist_empty(hhd)) {
3123		iter->pidx++;
3124		hnd = NULL;
3125		goto retry;
3126	}
3127
3128	if (!hnd)
3129		hnd = hhd->first;
3130	else {
3131		hnd = hnd->next;
3132		if (!hnd) {
3133			iter->pidx++;
3134			goto retry;
3135		}
3136	}
3137
3138	if (WARN_ON_ONCE(!hnd))
3139		return NULL;
3140
3141	iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3142
3143	return iter;
3144}
3145
3146static void *t_probe_start(struct seq_file *m, loff_t *pos)
3147{
3148	struct ftrace_iterator *iter = m->private;
3149	void *p = NULL;
3150	loff_t l;
3151
3152	if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3153		return NULL;
3154
3155	if (iter->mod_pos > *pos)
3156		return NULL;
3157
3158	iter->probe = NULL;
3159	iter->probe_entry = NULL;
3160	iter->pidx = 0;
3161	for (l = 0; l <= (*pos - iter->mod_pos); ) {
3162		p = t_probe_next(m, &l);
3163		if (!p)
3164			break;
3165	}
3166	if (!p)
3167		return NULL;
3168
3169	/* Only set this if we have an item */
3170	iter->flags |= FTRACE_ITER_PROBE;
3171
3172	return iter;
3173}
3174
3175static int
3176t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3177{
3178	struct ftrace_func_entry *probe_entry;
3179	struct ftrace_probe_ops *probe_ops;
3180	struct ftrace_func_probe *probe;
3181
3182	probe = iter->probe;
3183	probe_entry = iter->probe_entry;
3184
3185	if (WARN_ON_ONCE(!probe || !probe_entry))
3186		return -EIO;
3187
3188	probe_ops = probe->probe_ops;
 
3189
3190	if (probe_ops->print)
3191		return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3192
3193	seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3194		   (void *)probe_ops->func);
 
3195
3196	return 0;
3197}
3198
3199static void *
3200t_mod_next(struct seq_file *m, loff_t *pos)
3201{
3202	struct ftrace_iterator *iter = m->private;
3203	struct trace_array *tr = iter->tr;
3204
3205	(*pos)++;
3206	iter->pos = *pos;
3207
3208	iter->mod_list = iter->mod_list->next;
3209
3210	if (iter->mod_list == &tr->mod_trace ||
3211	    iter->mod_list == &tr->mod_notrace) {
3212		iter->flags &= ~FTRACE_ITER_MOD;
3213		return NULL;
3214	}
3215
3216	iter->mod_pos = *pos;
3217
3218	return iter;
3219}
3220
3221static void *t_mod_start(struct seq_file *m, loff_t *pos)
3222{
3223	struct ftrace_iterator *iter = m->private;
3224	void *p = NULL;
3225	loff_t l;
3226
3227	if (iter->func_pos > *pos)
3228		return NULL;
3229
3230	iter->mod_pos = iter->func_pos;
3231
3232	/* probes are only available if tr is set */
3233	if (!iter->tr)
3234		return NULL;
3235
3236	for (l = 0; l <= (*pos - iter->func_pos); ) {
3237		p = t_mod_next(m, &l);
3238		if (!p)
3239			break;
3240	}
3241	if (!p) {
3242		iter->flags &= ~FTRACE_ITER_MOD;
3243		return t_probe_start(m, pos);
3244	}
3245
3246	/* Only set this if we have an item */
3247	iter->flags |= FTRACE_ITER_MOD;
3248
3249	return iter;
3250}
3251
3252static int
3253t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3254{
3255	struct ftrace_mod_load *ftrace_mod;
3256	struct trace_array *tr = iter->tr;
3257
3258	if (WARN_ON_ONCE(!iter->mod_list) ||
3259			 iter->mod_list == &tr->mod_trace ||
3260			 iter->mod_list == &tr->mod_notrace)
3261		return -EIO;
3262
3263	ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3264
3265	if (ftrace_mod->func)
3266		seq_printf(m, "%s", ftrace_mod->func);
3267	else
3268		seq_putc(m, '*');
3269
3270	seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3271
3272	return 0;
3273}
3274
3275static void *
3276t_func_next(struct seq_file *m, loff_t *pos)
3277{
3278	struct ftrace_iterator *iter = m->private;
3279	struct dyn_ftrace *rec = NULL;
3280
3281	(*pos)++;
 
 
 
 
3282
3283 retry:
3284	if (iter->idx >= iter->pg->index) {
3285		if (iter->pg->next) {
3286			iter->pg = iter->pg->next;
3287			iter->idx = 0;
3288			goto retry;
3289		}
3290	} else {
3291		rec = &iter->pg->records[iter->idx++];
3292		if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3293		     !ftrace_lookup_ip(iter->hash, rec->ip)) ||
 
 
 
3294
3295		    ((iter->flags & FTRACE_ITER_ENABLED) &&
3296		     !(rec->flags & FTRACE_FL_ENABLED))) {
3297
3298			rec = NULL;
3299			goto retry;
3300		}
3301	}
3302
3303	if (!rec)
3304		return NULL;
3305
3306	iter->pos = iter->func_pos = *pos;
3307	iter->func = rec;
3308
3309	return iter;
3310}
3311
3312static void *
3313t_next(struct seq_file *m, void *v, loff_t *pos)
3314{
3315	struct ftrace_iterator *iter = m->private;
3316	loff_t l = *pos; /* t_probe_start() must use original pos */
3317	void *ret;
3318
3319	if (unlikely(ftrace_disabled))
3320		return NULL;
3321
3322	if (iter->flags & FTRACE_ITER_PROBE)
3323		return t_probe_next(m, pos);
3324
3325	if (iter->flags & FTRACE_ITER_MOD)
3326		return t_mod_next(m, pos);
3327
3328	if (iter->flags & FTRACE_ITER_PRINTALL) {
3329		/* next must increment pos, and t_probe_start does not */
3330		(*pos)++;
3331		return t_mod_start(m, &l);
3332	}
3333
3334	ret = t_func_next(m, pos);
3335
3336	if (!ret)
3337		return t_mod_start(m, &l);
3338
3339	return ret;
3340}
3341
3342static void reset_iter_read(struct ftrace_iterator *iter)
3343{
3344	iter->pos = 0;
3345	iter->func_pos = 0;
3346	iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3347}
3348
3349static void *t_start(struct seq_file *m, loff_t *pos)
3350{
3351	struct ftrace_iterator *iter = m->private;
 
3352	void *p = NULL;
3353	loff_t l;
3354
3355	mutex_lock(&ftrace_lock);
3356
3357	if (unlikely(ftrace_disabled))
3358		return NULL;
3359
3360	/*
3361	 * If an lseek was done, then reset and start from beginning.
3362	 */
3363	if (*pos < iter->pos)
3364		reset_iter_read(iter);
3365
3366	/*
3367	 * For set_ftrace_filter reading, if we have the filter
3368	 * off, we can short cut and just print out that all
3369	 * functions are enabled.
3370	 */
3371	if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3372	    ftrace_hash_empty(iter->hash)) {
3373		iter->func_pos = 1; /* Account for the message */
3374		if (*pos > 0)
3375			return t_mod_start(m, pos);
3376		iter->flags |= FTRACE_ITER_PRINTALL;
3377		/* reset in case of seek/pread */
3378		iter->flags &= ~FTRACE_ITER_PROBE;
3379		return iter;
3380	}
3381
3382	if (iter->flags & FTRACE_ITER_MOD)
3383		return t_mod_start(m, pos);
3384
3385	/*
3386	 * Unfortunately, we need to restart at ftrace_pages_start
3387	 * every time we let go of the ftrace_mutex. This is because
3388	 * those pointers can change without the lock.
3389	 */
3390	iter->pg = ftrace_pages_start;
3391	iter->idx = 0;
3392	for (l = 0; l <= *pos; ) {
3393		p = t_func_next(m, &l);
3394		if (!p)
3395			break;
3396	}
3397
3398	if (!p)
3399		return t_mod_start(m, pos);
3400
3401	return iter;
3402}
3403
3404static void t_stop(struct seq_file *m, void *p)
3405{
3406	mutex_unlock(&ftrace_lock);
3407}
3408
3409void * __weak
3410arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3411{
3412	return NULL;
3413}
3414
3415static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3416				struct dyn_ftrace *rec)
3417{
3418	void *ptr;
3419
3420	ptr = arch_ftrace_trampoline_func(ops, rec);
3421	if (ptr)
3422		seq_printf(m, " ->%pS", ptr);
3423}
3424
3425static int t_show(struct seq_file *m, void *v)
3426{
3427	struct ftrace_iterator *iter = m->private;
3428	struct dyn_ftrace *rec;
3429
3430	if (iter->flags & FTRACE_ITER_PROBE)
3431		return t_probe_show(m, iter);
3432
3433	if (iter->flags & FTRACE_ITER_MOD)
3434		return t_mod_show(m, iter);
3435
3436	if (iter->flags & FTRACE_ITER_PRINTALL) {
3437		if (iter->flags & FTRACE_ITER_NOTRACE)
3438			seq_puts(m, "#### no functions disabled ####\n");
3439		else
3440			seq_puts(m, "#### all functions enabled ####\n");
3441		return 0;
3442	}
3443
3444	rec = iter->func;
3445
3446	if (!rec)
3447		return 0;
3448
3449	seq_printf(m, "%ps", (void *)rec->ip);
3450	if (iter->flags & FTRACE_ITER_ENABLED) {
3451		struct ftrace_ops *ops;
3452
3453		seq_printf(m, " (%ld)%s%s",
3454			   ftrace_rec_count(rec),
3455			   rec->flags & FTRACE_FL_REGS ? " R" : "  ",
3456			   rec->flags & FTRACE_FL_IPMODIFY ? " I" : "  ");
3457		if (rec->flags & FTRACE_FL_TRAMP_EN) {
3458			ops = ftrace_find_tramp_ops_any(rec);
3459			if (ops) {
3460				do {
3461					seq_printf(m, "\ttramp: %pS (%pS)",
3462						   (void *)ops->trampoline,
3463						   (void *)ops->func);
3464					add_trampoline_func(m, ops, rec);
3465					ops = ftrace_find_tramp_ops_next(rec, ops);
3466				} while (ops);
3467			} else
3468				seq_puts(m, "\ttramp: ERROR!");
3469		} else {
3470			add_trampoline_func(m, NULL, rec);
3471		}
3472	}	
3473
3474	seq_putc(m, '\n');
3475
3476	return 0;
3477}
3478
3479static const struct seq_operations show_ftrace_seq_ops = {
3480	.start = t_start,
3481	.next = t_next,
3482	.stop = t_stop,
3483	.show = t_show,
3484};
3485
3486static int
3487ftrace_avail_open(struct inode *inode, struct file *file)
3488{
3489	struct ftrace_iterator *iter;
3490	int ret;
3491
3492	ret = security_locked_down(LOCKDOWN_TRACEFS);
3493	if (ret)
3494		return ret;
3495
3496	if (unlikely(ftrace_disabled))
3497		return -ENODEV;
3498
3499	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3500	if (!iter)
3501		return -ENOMEM;
3502
3503	iter->pg = ftrace_pages_start;
3504	iter->ops = &global_ops;
3505
3506	return 0;
3507}
3508
3509static int
3510ftrace_enabled_open(struct inode *inode, struct file *file)
3511{
3512	struct ftrace_iterator *iter;
3513
3514	/*
3515	 * This shows us what functions are currently being
3516	 * traced and by what. Not sure if we want lockdown
3517	 * to hide such critical information for an admin.
3518	 * Although, perhaps it can show information we don't
3519	 * want people to see, but if something is tracing
3520	 * something, we probably want to know about it.
3521	 */
3522
3523	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3524	if (!iter)
3525		return -ENOMEM;
 
 
 
3526
3527	iter->pg = ftrace_pages_start;
3528	iter->flags = FTRACE_ITER_ENABLED;
3529	iter->ops = &global_ops;
3530
3531	return 0;
 
 
 
 
3532}
3533
3534/**
3535 * ftrace_regex_open - initialize function tracer filter files
3536 * @ops: The ftrace_ops that hold the hash filters
3537 * @flag: The type of filter to process
3538 * @inode: The inode, usually passed in to your open routine
3539 * @file: The file, usually passed in to your open routine
3540 *
3541 * ftrace_regex_open() initializes the filter files for the
3542 * @ops. Depending on @flag it may process the filter hash or
3543 * the notrace hash of @ops. With this called from the open
3544 * routine, you can use ftrace_filter_write() for the write
3545 * routine if @flag has FTRACE_ITER_FILTER set, or
3546 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3547 * tracing_lseek() should be used as the lseek routine, and
3548 * release must call ftrace_regex_release().
3549 */
3550int
3551ftrace_regex_open(struct ftrace_ops *ops, int flag,
3552		  struct inode *inode, struct file *file)
3553{
3554	struct ftrace_iterator *iter;
3555	struct ftrace_hash *hash;
3556	struct list_head *mod_head;
3557	struct trace_array *tr = ops->private;
3558	int ret = -ENOMEM;
3559
3560	ftrace_ops_init(ops);
3561
3562	if (unlikely(ftrace_disabled))
3563		return -ENODEV;
3564
3565	if (tracing_check_open_get_tr(tr))
3566		return -ENODEV;
3567
3568	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3569	if (!iter)
3570		goto out;
3571
3572	if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3573		goto out;
 
 
3574
3575	iter->ops = ops;
3576	iter->flags = flag;
3577	iter->tr = tr;
3578
3579	mutex_lock(&ops->func_hash->regex_lock);
3580
3581	if (flag & FTRACE_ITER_NOTRACE) {
3582		hash = ops->func_hash->notrace_hash;
3583		mod_head = tr ? &tr->mod_notrace : NULL;
3584	} else {
3585		hash = ops->func_hash->filter_hash;
3586		mod_head = tr ? &tr->mod_trace : NULL;
3587	}
3588
3589	iter->mod_list = mod_head;
3590
3591	if (file->f_mode & FMODE_WRITE) {
3592		const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3593
3594		if (file->f_flags & O_TRUNC) {
3595			iter->hash = alloc_ftrace_hash(size_bits);
3596			clear_ftrace_mod_list(mod_head);
3597	        } else {
3598			iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3599		}
3600
3601		if (!iter->hash) {
3602			trace_parser_put(&iter->parser);
 
 
3603			goto out_unlock;
3604		}
3605	} else
3606		iter->hash = hash;
3607
3608	ret = 0;
 
 
3609
3610	if (file->f_mode & FMODE_READ) {
3611		iter->pg = ftrace_pages_start;
3612
3613		ret = seq_open(file, &show_ftrace_seq_ops);
3614		if (!ret) {
3615			struct seq_file *m = file->private_data;
3616			m->private = iter;
3617		} else {
3618			/* Failed */
3619			free_ftrace_hash(iter->hash);
3620			trace_parser_put(&iter->parser);
 
3621		}
3622	} else
3623		file->private_data = iter;
3624
3625 out_unlock:
3626	mutex_unlock(&ops->func_hash->regex_lock);
3627
3628 out:
3629	if (ret) {
3630		kfree(iter);
3631		if (tr)
3632			trace_array_put(tr);
3633	}
3634
3635	return ret;
3636}
3637
3638static int
3639ftrace_filter_open(struct inode *inode, struct file *file)
3640{
3641	struct ftrace_ops *ops = inode->i_private;
3642
3643	/* Checks for tracefs lockdown */
3644	return ftrace_regex_open(ops,
3645			FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3646			inode, file);
3647}
3648
3649static int
3650ftrace_notrace_open(struct inode *inode, struct file *file)
3651{
3652	struct ftrace_ops *ops = inode->i_private;
3653
3654	/* Checks for tracefs lockdown */
3655	return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3656				 inode, file);
3657}
3658
3659/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
3660struct ftrace_glob {
3661	char *search;
3662	unsigned len;
3663	int type;
3664};
3665
3666/*
3667 * If symbols in an architecture don't correspond exactly to the user-visible
3668 * name of what they represent, it is possible to define this function to
3669 * perform the necessary adjustments.
3670*/
3671char * __weak arch_ftrace_match_adjust(char *str, const char *search)
3672{
3673	return str;
3674}
3675
3676static int ftrace_match(char *str, struct ftrace_glob *g)
3677{
3678	int matched = 0;
3679	int slen;
3680
3681	str = arch_ftrace_match_adjust(str, g->search);
3682
3683	switch (g->type) {
3684	case MATCH_FULL:
3685		if (strcmp(str, g->search) == 0)
3686			matched = 1;
3687		break;
3688	case MATCH_FRONT_ONLY:
3689		if (strncmp(str, g->search, g->len) == 0)
3690			matched = 1;
3691		break;
3692	case MATCH_MIDDLE_ONLY:
3693		if (strstr(str, g->search))
3694			matched = 1;
3695		break;
3696	case MATCH_END_ONLY:
3697		slen = strlen(str);
3698		if (slen >= g->len &&
3699		    memcmp(str + slen - g->len, g->search, g->len) == 0)
3700			matched = 1;
3701		break;
3702	case MATCH_GLOB:
3703		if (glob_match(g->search, str))
3704			matched = 1;
3705		break;
3706	}
3707
3708	return matched;
3709}
3710
3711static int
3712enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
3713{
3714	struct ftrace_func_entry *entry;
3715	int ret = 0;
3716
3717	entry = ftrace_lookup_ip(hash, rec->ip);
3718	if (clear_filter) {
3719		/* Do nothing if it doesn't exist */
3720		if (!entry)
3721			return 0;
3722
3723		free_hash_entry(hash, entry);
3724	} else {
3725		/* Do nothing if it exists */
3726		if (entry)
3727			return 0;
3728
3729		ret = add_hash_entry(hash, rec->ip);
3730	}
3731	return ret;
3732}
3733
3734static int
3735add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
3736		 int clear_filter)
3737{
3738	long index = simple_strtoul(func_g->search, NULL, 0);
3739	struct ftrace_page *pg;
3740	struct dyn_ftrace *rec;
3741
3742	/* The index starts at 1 */
3743	if (--index < 0)
3744		return 0;
3745
3746	do_for_each_ftrace_rec(pg, rec) {
3747		if (pg->index <= index) {
3748			index -= pg->index;
3749			/* this is a double loop, break goes to the next page */
3750			break;
3751		}
3752		rec = &pg->records[index];
3753		enter_record(hash, rec, clear_filter);
3754		return 1;
3755	} while_for_each_ftrace_rec();
3756	return 0;
3757}
3758
3759static int
3760ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
3761		struct ftrace_glob *mod_g, int exclude_mod)
3762{
3763	char str[KSYM_SYMBOL_LEN];
3764	char *modname;
3765
3766	kallsyms_lookup(rec->ip, NULL, NULL, &modname, str);
3767
3768	if (mod_g) {
3769		int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
3770
3771		/* blank module name to match all modules */
3772		if (!mod_g->len) {
3773			/* blank module globbing: modname xor exclude_mod */
3774			if (!exclude_mod != !modname)
3775				goto func_match;
3776			return 0;
3777		}
3778
3779		/*
3780		 * exclude_mod is set to trace everything but the given
3781		 * module. If it is set and the module matches, then
3782		 * return 0. If it is not set, and the module doesn't match
3783		 * also return 0. Otherwise, check the function to see if
3784		 * that matches.
3785		 */
3786		if (!mod_matches == !exclude_mod)
3787			return 0;
3788func_match:
3789		/* blank search means to match all funcs in the mod */
3790		if (!func_g->len)
3791			return 1;
3792	}
3793
3794	return ftrace_match(str, func_g);
3795}
3796
3797static int
3798match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
 
3799{
 
3800	struct ftrace_page *pg;
3801	struct dyn_ftrace *rec;
3802	struct ftrace_glob func_g = { .type = MATCH_FULL };
3803	struct ftrace_glob mod_g = { .type = MATCH_FULL };
3804	struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
3805	int exclude_mod = 0;
3806	int found = 0;
3807	int ret;
3808	int clear_filter = 0;
3809
3810	if (func) {
3811		func_g.type = filter_parse_regex(func, len, &func_g.search,
3812						 &clear_filter);
3813		func_g.len = strlen(func_g.search);
3814	}
3815
3816	if (mod) {
3817		mod_g.type = filter_parse_regex(mod, strlen(mod),
3818				&mod_g.search, &exclude_mod);
3819		mod_g.len = strlen(mod_g.search);
3820	}
3821
3822	mutex_lock(&ftrace_lock);
3823
3824	if (unlikely(ftrace_disabled))
3825		goto out_unlock;
3826
3827	if (func_g.type == MATCH_INDEX) {
3828		found = add_rec_by_index(hash, &func_g, clear_filter);
3829		goto out_unlock;
3830	}
3831
3832	do_for_each_ftrace_rec(pg, rec) {
3833
3834		if (rec->flags & FTRACE_FL_DISABLED)
3835			continue;
3836
3837		if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
3838			ret = enter_record(hash, rec, clear_filter);
3839			if (ret < 0) {
3840				found = ret;
3841				goto out_unlock;
3842			}
3843			found = 1;
3844		}
3845	} while_for_each_ftrace_rec();
3846 out_unlock:
3847	mutex_unlock(&ftrace_lock);
3848
3849	return found;
3850}
3851
3852static int
3853ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
3854{
3855	return match_records(hash, buff, len, NULL);
3856}
3857
3858static void ftrace_ops_update_code(struct ftrace_ops *ops,
3859				   struct ftrace_ops_hash *old_hash)
3860{
3861	struct ftrace_ops *op;
3862
3863	if (!ftrace_enabled)
3864		return;
3865
3866	if (ops->flags & FTRACE_OPS_FL_ENABLED) {
3867		ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
3868		return;
3869	}
3870
3871	/*
3872	 * If this is the shared global_ops filter, then we need to
3873	 * check if there is another ops that shares it, is enabled.
3874	 * If so, we still need to run the modify code.
3875	 */
3876	if (ops->func_hash != &global_ops.local_hash)
3877		return;
3878
3879	do_for_each_ftrace_op(op, ftrace_ops_list) {
3880		if (op->func_hash == &global_ops.local_hash &&
3881		    op->flags & FTRACE_OPS_FL_ENABLED) {
3882			ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
3883			/* Only need to do this once */
3884			return;
3885		}
3886	} while_for_each_ftrace_op(op);
3887}
3888
3889static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
3890					   struct ftrace_hash **orig_hash,
3891					   struct ftrace_hash *hash,
3892					   int enable)
3893{
3894	struct ftrace_ops_hash old_hash_ops;
3895	struct ftrace_hash *old_hash;
3896	int ret;
3897
3898	old_hash = *orig_hash;
3899	old_hash_ops.filter_hash = ops->func_hash->filter_hash;
3900	old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
3901	ret = ftrace_hash_move(ops, enable, orig_hash, hash);
3902	if (!ret) {
3903		ftrace_ops_update_code(ops, &old_hash_ops);
3904		free_ftrace_hash_rcu(old_hash);
3905	}
3906	return ret;
3907}
3908
3909static bool module_exists(const char *module)
3910{
3911	/* All modules have the symbol __this_module */
3912	static const char this_mod[] = "__this_module";
3913	char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
3914	unsigned long val;
3915	int n;
3916
3917	n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
3918
3919	if (n > sizeof(modname) - 1)
3920		return false;
3921
3922	val = module_kallsyms_lookup_name(modname);
3923	return val != 0;
3924}
3925
3926static int cache_mod(struct trace_array *tr,
3927		     const char *func, char *module, int enable)
3928{
3929	struct ftrace_mod_load *ftrace_mod, *n;
3930	struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
3931	int ret;
3932
3933	mutex_lock(&ftrace_lock);
3934
3935	/* We do not cache inverse filters */
3936	if (func[0] == '!') {
3937		func++;
3938		ret = -EINVAL;
3939
3940		/* Look to remove this hash */
3941		list_for_each_entry_safe(ftrace_mod, n, head, list) {
3942			if (strcmp(ftrace_mod->module, module) != 0)
3943				continue;
3944
3945			/* no func matches all */
3946			if (strcmp(func, "*") == 0 ||
3947			    (ftrace_mod->func &&
3948			     strcmp(ftrace_mod->func, func) == 0)) {
3949				ret = 0;
3950				free_ftrace_mod(ftrace_mod);
3951				continue;
3952			}
3953		}
3954		goto out;
3955	}
3956
3957	ret = -EINVAL;
3958	/* We only care about modules that have not been loaded yet */
3959	if (module_exists(module))
3960		goto out;
3961
3962	/* Save this string off, and execute it when the module is loaded */
3963	ret = ftrace_add_mod(tr, func, module, enable);
3964 out:
3965	mutex_unlock(&ftrace_lock);
3966
3967	return ret;
3968}
3969
3970static int
3971ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
3972		 int reset, int enable);
3973
3974#ifdef CONFIG_MODULES
3975static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
3976			     char *mod, bool enable)
3977{
3978	struct ftrace_mod_load *ftrace_mod, *n;
3979	struct ftrace_hash **orig_hash, *new_hash;
3980	LIST_HEAD(process_mods);
3981	char *func;
3982	int ret;
3983
3984	mutex_lock(&ops->func_hash->regex_lock);
3985
3986	if (enable)
3987		orig_hash = &ops->func_hash->filter_hash;
3988	else
3989		orig_hash = &ops->func_hash->notrace_hash;
3990
3991	new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
3992					      *orig_hash);
3993	if (!new_hash)
3994		goto out; /* warn? */
3995
3996	mutex_lock(&ftrace_lock);
3997
3998	list_for_each_entry_safe(ftrace_mod, n, head, list) {
3999
4000		if (strcmp(ftrace_mod->module, mod) != 0)
4001			continue;
4002
4003		if (ftrace_mod->func)
4004			func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4005		else
4006			func = kstrdup("*", GFP_KERNEL);
4007
4008		if (!func) /* warn? */
4009			continue;
4010
4011		list_del(&ftrace_mod->list);
4012		list_add(&ftrace_mod->list, &process_mods);
4013
4014		/* Use the newly allocated func, as it may be "*" */
4015		kfree(ftrace_mod->func);
4016		ftrace_mod->func = func;
4017	}
4018
4019	mutex_unlock(&ftrace_lock);
4020
4021	list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4022
4023		func = ftrace_mod->func;
4024
4025		/* Grabs ftrace_lock, which is why we have this extra step */
4026		match_records(new_hash, func, strlen(func), mod);
4027		free_ftrace_mod(ftrace_mod);
4028	}
4029
4030	if (enable && list_empty(head))
4031		new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4032
4033	mutex_lock(&ftrace_lock);
4034
4035	ret = ftrace_hash_move_and_update_ops(ops, orig_hash,
4036					      new_hash, enable);
4037	mutex_unlock(&ftrace_lock);
4038
4039 out:
4040	mutex_unlock(&ops->func_hash->regex_lock);
4041
4042	free_ftrace_hash(new_hash);
4043}
4044
4045static void process_cached_mods(const char *mod_name)
4046{
4047	struct trace_array *tr;
4048	char *mod;
4049
4050	mod = kstrdup(mod_name, GFP_KERNEL);
4051	if (!mod)
4052		return;
4053
4054	mutex_lock(&trace_types_lock);
4055	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4056		if (!list_empty(&tr->mod_trace))
4057			process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4058		if (!list_empty(&tr->mod_notrace))
4059			process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4060	}
4061	mutex_unlock(&trace_types_lock);
4062
4063	kfree(mod);
4064}
4065#endif
4066
4067/*
4068 * We register the module command as a template to show others how
4069 * to register the a command as well.
4070 */
4071
4072static int
4073ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4074		    char *func_orig, char *cmd, char *module, int enable)
4075{
4076	char *func;
4077	int ret;
4078
4079	/* match_records() modifies func, and we need the original */
4080	func = kstrdup(func_orig, GFP_KERNEL);
4081	if (!func)
4082		return -ENOMEM;
4083
4084	/*
4085	 * cmd == 'mod' because we only registered this func
4086	 * for the 'mod' ftrace_func_command.
4087	 * But if you register one func with multiple commands,
4088	 * you can tell which command was used by the cmd
4089	 * parameter.
4090	 */
4091	ret = match_records(hash, func, strlen(func), module);
4092	kfree(func);
4093
 
 
 
 
 
 
 
 
 
4094	if (!ret)
4095		return cache_mod(tr, func_orig, module, enable);
4096	if (ret < 0)
4097		return ret;
 
4098	return 0;
4099}
4100
4101static struct ftrace_func_command ftrace_mod_cmd = {
4102	.name			= "mod",
4103	.func			= ftrace_mod_callback,
4104};
4105
4106static int __init ftrace_mod_cmd_init(void)
4107{
4108	return register_ftrace_command(&ftrace_mod_cmd);
4109}
4110core_initcall(ftrace_mod_cmd_init);
4111
4112static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4113				      struct ftrace_ops *op, struct pt_regs *pt_regs)
4114{
4115	struct ftrace_probe_ops *probe_ops;
4116	struct ftrace_func_probe *probe;
 
 
 
4117
4118	probe = container_of(op, struct ftrace_func_probe, ops);
4119	probe_ops = probe->probe_ops;
 
 
4120
4121	/*
4122	 * Disable preemption for these calls to prevent a RCU grace
4123	 * period. This syncs the hash iteration and freeing of items
4124	 * on the hash. rcu_read_lock is too dangerous here.
4125	 */
4126	preempt_disable_notrace();
4127	probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
 
 
 
4128	preempt_enable_notrace();
4129}
4130
4131struct ftrace_func_map {
4132	struct ftrace_func_entry	entry;
4133	void				*data;
4134};
4135
4136struct ftrace_func_mapper {
4137	struct ftrace_hash		hash;
4138};
4139
4140/**
4141 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4142 *
4143 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4144 */
4145struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4146{
4147	struct ftrace_hash *hash;
4148
4149	/*
4150	 * The mapper is simply a ftrace_hash, but since the entries
4151	 * in the hash are not ftrace_func_entry type, we define it
4152	 * as a separate structure.
4153	 */
4154	hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4155	return (struct ftrace_func_mapper *)hash;
4156}
4157
4158/**
4159 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4160 * @mapper: The mapper that has the ip maps
4161 * @ip: the instruction pointer to find the data for
4162 *
4163 * Returns the data mapped to @ip if found otherwise NULL. The return
4164 * is actually the address of the mapper data pointer. The address is
4165 * returned for use cases where the data is no bigger than a long, and
4166 * the user can use the data pointer as its data instead of having to
4167 * allocate more memory for the reference.
4168 */
4169void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4170				  unsigned long ip)
4171{
4172	struct ftrace_func_entry *entry;
4173	struct ftrace_func_map *map;
4174
4175	entry = ftrace_lookup_ip(&mapper->hash, ip);
4176	if (!entry)
4177		return NULL;
4178
4179	map = (struct ftrace_func_map *)entry;
4180	return &map->data;
4181}
4182
4183/**
4184 * ftrace_func_mapper_add_ip - Map some data to an ip
4185 * @mapper: The mapper that has the ip maps
4186 * @ip: The instruction pointer address to map @data to
4187 * @data: The data to map to @ip
4188 *
4189 * Returns 0 on succes otherwise an error.
4190 */
4191int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4192			      unsigned long ip, void *data)
4193{
4194	struct ftrace_func_entry *entry;
4195	struct ftrace_func_map *map;
4196
4197	entry = ftrace_lookup_ip(&mapper->hash, ip);
4198	if (entry)
4199		return -EBUSY;
4200
4201	map = kmalloc(sizeof(*map), GFP_KERNEL);
4202	if (!map)
4203		return -ENOMEM;
4204
4205	map->entry.ip = ip;
4206	map->data = data;
4207
4208	__add_hash_entry(&mapper->hash, &map->entry);
4209
4210	return 0;
4211}
4212
4213/**
4214 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4215 * @mapper: The mapper that has the ip maps
4216 * @ip: The instruction pointer address to remove the data from
4217 *
4218 * Returns the data if it is found, otherwise NULL.
4219 * Note, if the data pointer is used as the data itself, (see 
4220 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4221 * if the data pointer was set to zero.
4222 */
4223void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4224				   unsigned long ip)
4225{
4226	struct ftrace_func_entry *entry;
4227	struct ftrace_func_map *map;
4228	void *data;
4229
4230	entry = ftrace_lookup_ip(&mapper->hash, ip);
4231	if (!entry)
4232		return NULL;
 
 
 
4233
4234	map = (struct ftrace_func_map *)entry;
4235	data = map->data;
 
 
 
 
 
 
4236
4237	remove_hash_entry(&mapper->hash, entry);
4238	kfree(entry);
4239
4240	return data;
4241}
4242
4243/**
4244 * free_ftrace_func_mapper - free a mapping of ips and data
4245 * @mapper: The mapper that has the ip maps
4246 * @free_func: A function to be called on each data item.
4247 *
4248 * This is used to free the function mapper. The @free_func is optional
4249 * and can be used if the data needs to be freed as well.
4250 */
4251void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4252			     ftrace_mapper_func free_func)
4253{
4254	struct ftrace_func_entry *entry;
4255	struct ftrace_func_map *map;
4256	struct hlist_head *hhd;
4257	int size, i;
4258
4259	if (!mapper)
4260		return;
4261
4262	if (free_func && mapper->hash.count) {
4263		size = 1 << mapper->hash.size_bits;
4264		for (i = 0; i < size; i++) {
4265			hhd = &mapper->hash.buckets[i];
4266			hlist_for_each_entry(entry, hhd, hlist) {
4267				map = (struct ftrace_func_map *)entry;
4268				free_func(map);
4269			}
4270		}
4271	}
4272	free_ftrace_hash(&mapper->hash);
4273}
4274
4275static void release_probe(struct ftrace_func_probe *probe)
4276{
4277	struct ftrace_probe_ops *probe_ops;
4278
4279	mutex_lock(&ftrace_lock);
4280
4281	WARN_ON(probe->ref <= 0);
4282
4283	/* Subtract the ref that was used to protect this instance */
4284	probe->ref--;
4285
4286	if (!probe->ref) {
4287		probe_ops = probe->probe_ops;
4288		/*
4289		 * Sending zero as ip tells probe_ops to free
4290		 * the probe->data itself
4291		 */
4292		if (probe_ops->free)
4293			probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4294		list_del(&probe->list);
4295		kfree(probe);
4296	}
4297	mutex_unlock(&ftrace_lock);
4298}
4299
4300static void acquire_probe_locked(struct ftrace_func_probe *probe)
 
4301{
4302	/*
4303	 * Add one ref to keep it from being freed when releasing the
4304	 * ftrace_lock mutex.
4305	 */
4306	probe->ref++;
4307}
4308
4309int
4310register_ftrace_function_probe(char *glob, struct trace_array *tr,
4311			       struct ftrace_probe_ops *probe_ops,
4312			       void *data)
4313{
4314	struct ftrace_func_entry *entry;
4315	struct ftrace_func_probe *probe;
4316	struct ftrace_hash **orig_hash;
4317	struct ftrace_hash *old_hash;
4318	struct ftrace_hash *hash;
 
 
 
 
4319	int count = 0;
4320	int size;
4321	int ret;
4322	int i;
4323
4324	if (WARN_ON(!tr))
4325		return -EINVAL;
4326
4327	/* We do not support '!' for function probes */
4328	if (WARN_ON(glob[0] == '!'))
4329		return -EINVAL;
4330
 
4331
4332	mutex_lock(&ftrace_lock);
4333	/* Check if the probe_ops is already registered */
4334	list_for_each_entry(probe, &tr->func_probes, list) {
4335		if (probe->probe_ops == probe_ops)
4336			break;
4337	}
4338	if (&probe->list == &tr->func_probes) {
4339		probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4340		if (!probe) {
4341			mutex_unlock(&ftrace_lock);
4342			return -ENOMEM;
4343		}
4344		probe->probe_ops = probe_ops;
4345		probe->ops.func = function_trace_probe_call;
4346		probe->tr = tr;
4347		ftrace_ops_init(&probe->ops);
4348		list_add(&probe->list, &tr->func_probes);
4349	}
4350
4351	acquire_probe_locked(probe);
4352
4353	mutex_unlock(&ftrace_lock);
 
4354
4355	/*
4356	 * Note, there's a small window here that the func_hash->filter_hash
4357	 * may be NULL or empty. Need to be carefule when reading the loop.
4358	 */
4359	mutex_lock(&probe->ops.func_hash->regex_lock);
4360
4361	orig_hash = &probe->ops.func_hash->filter_hash;
4362	old_hash = *orig_hash;
4363	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4364
4365	if (!hash) {
4366		ret = -ENOMEM;
4367		goto out;
4368	}
4369
4370	ret = ftrace_match_records(hash, glob, strlen(glob));
 
 
 
 
 
 
4371
4372	/* Nothing found? */
4373	if (!ret)
4374		ret = -EINVAL;
4375
4376	if (ret < 0)
4377		goto out;
4378
4379	size = 1 << hash->size_bits;
4380	for (i = 0; i < size; i++) {
4381		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4382			if (ftrace_lookup_ip(old_hash, entry->ip))
 
 
 
 
 
4383				continue;
4384			/*
4385			 * The caller might want to do something special
4386			 * for each function we find. We call the callback
4387			 * to give the caller an opportunity to do so.
4388			 */
4389			if (probe_ops->init) {
4390				ret = probe_ops->init(probe_ops, tr,
4391						      entry->ip, data,
4392						      &probe->data);
4393				if (ret < 0) {
4394					if (probe_ops->free && count)
4395						probe_ops->free(probe_ops, tr,
4396								0, probe->data);
4397					probe->data = NULL;
4398					goto out;
4399				}
4400			}
4401			count++;
4402		}
4403	}
4404
4405	mutex_lock(&ftrace_lock);
 
 
 
 
 
4406
4407	if (!count) {
4408		/* Nothing was added? */
4409		ret = -EINVAL;
4410		goto out_unlock;
4411	}
4412
4413	ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4414					      hash, 1);
4415	if (ret < 0)
4416		goto err_unlock;
4417
4418	/* One ref for each new function traced */
4419	probe->ref += count;
 
 
 
4420
4421	if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4422		ret = ftrace_startup(&probe->ops, 0);
4423
4424 out_unlock:
4425	mutex_unlock(&ftrace_lock);
4426
4427	if (!ret)
4428		ret = count;
4429 out:
4430	mutex_unlock(&probe->ops.func_hash->regex_lock);
4431	free_ftrace_hash(hash);
4432
4433	release_probe(probe);
4434
4435	return ret;
4436
4437 err_unlock:
4438	if (!probe_ops->free || !count)
4439		goto out_unlock;
4440
4441	/* Failed to do the move, need to call the free functions */
4442	for (i = 0; i < size; i++) {
4443		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4444			if (ftrace_lookup_ip(old_hash, entry->ip))
4445				continue;
4446			probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4447		}
4448	}
4449	goto out_unlock;
4450}
4451
4452int
4453unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4454				      struct ftrace_probe_ops *probe_ops)
 
 
 
 
 
4455{
4456	struct ftrace_ops_hash old_hash_ops;
4457	struct ftrace_func_entry *entry;
4458	struct ftrace_func_probe *probe;
4459	struct ftrace_glob func_g;
4460	struct ftrace_hash **orig_hash;
4461	struct ftrace_hash *old_hash;
4462	struct ftrace_hash *hash = NULL;
4463	struct hlist_node *tmp;
4464	struct hlist_head hhd;
4465	char str[KSYM_SYMBOL_LEN];
4466	int count = 0;
4467	int i, ret = -ENODEV;
4468	int size;
4469
4470	if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4471		func_g.search = NULL;
4472	else {
4473		int not;
4474
4475		func_g.type = filter_parse_regex(glob, strlen(glob),
4476						 &func_g.search, &not);
4477		func_g.len = strlen(func_g.search);
4478
4479		/* we do not support '!' for function probes */
4480		if (WARN_ON(not))
4481			return -EINVAL;
4482	}
4483
4484	mutex_lock(&ftrace_lock);
4485	/* Check if the probe_ops is already registered */
4486	list_for_each_entry(probe, &tr->func_probes, list) {
4487		if (probe->probe_ops == probe_ops)
4488			break;
4489	}
4490	if (&probe->list == &tr->func_probes)
4491		goto err_unlock_ftrace;
4492
4493	ret = -EINVAL;
4494	if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4495		goto err_unlock_ftrace;
4496
4497	acquire_probe_locked(probe);
4498
4499	mutex_unlock(&ftrace_lock);
4500
4501	mutex_lock(&probe->ops.func_hash->regex_lock);
4502
4503	orig_hash = &probe->ops.func_hash->filter_hash;
4504	old_hash = *orig_hash;
4505
4506	if (ftrace_hash_empty(old_hash))
4507		goto out_unlock;
4508
4509	old_hash_ops.filter_hash = old_hash;
4510	/* Probes only have filters */
4511	old_hash_ops.notrace_hash = NULL;
4512
4513	ret = -ENOMEM;
4514	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4515	if (!hash)
4516		goto out_unlock;
4517
4518	INIT_HLIST_HEAD(&hhd);
4519
4520	size = 1 << hash->size_bits;
4521	for (i = 0; i < size; i++) {
4522		hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4523
4524			if (func_g.search) {
 
 
 
 
4525				kallsyms_lookup(entry->ip, NULL, NULL,
4526						NULL, str);
4527				if (!ftrace_match(str, &func_g))
4528					continue;
4529			}
4530			count++;
4531			remove_hash_entry(hash, entry);
4532			hlist_add_head(&entry->hlist, &hhd);
4533		}
4534	}
4535
4536	/* Nothing found? */
4537	if (!count) {
4538		ret = -EINVAL;
4539		goto out_unlock;
4540	}
4541
 
 
 
 
4542	mutex_lock(&ftrace_lock);
4543
4544	WARN_ON(probe->ref < count);
4545
4546	probe->ref -= count;
4547
4548	if (ftrace_hash_empty(hash))
4549		ftrace_shutdown(&probe->ops, 0);
4550
4551	ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4552					      hash, 1);
4553
4554	/* still need to update the function call sites */
4555	if (ftrace_enabled && !ftrace_hash_empty(hash))
4556		ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4557				       &old_hash_ops);
4558	synchronize_rcu();
4559
4560	hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4561		hlist_del(&entry->hlist);
4562		if (probe_ops->free)
4563			probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4564		kfree(entry);
4565	}
4566	mutex_unlock(&ftrace_lock);
4567
4568 out_unlock:
4569	mutex_unlock(&probe->ops.func_hash->regex_lock);
4570	free_ftrace_hash(hash);
 
4571
4572	release_probe(probe);
4573
4574	return ret;
4575
4576 err_unlock_ftrace:
4577	mutex_unlock(&ftrace_lock);
4578	return ret;
4579}
4580
4581void clear_ftrace_function_probes(struct trace_array *tr)
 
4582{
4583	struct ftrace_func_probe *probe, *n;
 
4584
4585	list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4586		unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
 
4587}
4588
4589static LIST_HEAD(ftrace_commands);
4590static DEFINE_MUTEX(ftrace_cmd_mutex);
4591
4592/*
4593 * Currently we only register ftrace commands from __init, so mark this
4594 * __init too.
4595 */
4596__init int register_ftrace_command(struct ftrace_func_command *cmd)
4597{
4598	struct ftrace_func_command *p;
4599	int ret = 0;
4600
4601	mutex_lock(&ftrace_cmd_mutex);
4602	list_for_each_entry(p, &ftrace_commands, list) {
4603		if (strcmp(cmd->name, p->name) == 0) {
4604			ret = -EBUSY;
4605			goto out_unlock;
4606		}
4607	}
4608	list_add(&cmd->list, &ftrace_commands);
4609 out_unlock:
4610	mutex_unlock(&ftrace_cmd_mutex);
4611
4612	return ret;
4613}
4614
4615/*
4616 * Currently we only unregister ftrace commands from __init, so mark
4617 * this __init too.
4618 */
4619__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4620{
4621	struct ftrace_func_command *p, *n;
4622	int ret = -ENODEV;
4623
4624	mutex_lock(&ftrace_cmd_mutex);
4625	list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4626		if (strcmp(cmd->name, p->name) == 0) {
4627			ret = 0;
4628			list_del_init(&p->list);
4629			goto out_unlock;
4630		}
4631	}
4632 out_unlock:
4633	mutex_unlock(&ftrace_cmd_mutex);
4634
4635	return ret;
4636}
4637
4638static int ftrace_process_regex(struct ftrace_iterator *iter,
4639				char *buff, int len, int enable)
4640{
4641	struct ftrace_hash *hash = iter->hash;
4642	struct trace_array *tr = iter->ops->private;
4643	char *func, *command, *next = buff;
4644	struct ftrace_func_command *p;
4645	int ret = -EINVAL;
4646
4647	func = strsep(&next, ":");
4648
4649	if (!next) {
4650		ret = ftrace_match_records(hash, func, len);
4651		if (!ret)
4652			ret = -EINVAL;
4653		if (ret < 0)
4654			return ret;
4655		return 0;
4656	}
4657
4658	/* command found */
4659
4660	command = strsep(&next, ":");
4661
4662	mutex_lock(&ftrace_cmd_mutex);
4663	list_for_each_entry(p, &ftrace_commands, list) {
4664		if (strcmp(p->name, command) == 0) {
4665			ret = p->func(tr, hash, func, command, next, enable);
4666			goto out_unlock;
4667		}
4668	}
4669 out_unlock:
4670	mutex_unlock(&ftrace_cmd_mutex);
4671
4672	return ret;
4673}
4674
4675static ssize_t
4676ftrace_regex_write(struct file *file, const char __user *ubuf,
4677		   size_t cnt, loff_t *ppos, int enable)
4678{
4679	struct ftrace_iterator *iter;
4680	struct trace_parser *parser;
4681	ssize_t ret, read;
4682
4683	if (!cnt)
4684		return 0;
4685
4686	if (file->f_mode & FMODE_READ) {
4687		struct seq_file *m = file->private_data;
4688		iter = m->private;
4689	} else
4690		iter = file->private_data;
4691
4692	if (unlikely(ftrace_disabled))
4693		return -ENODEV;
4694
4695	/* iter->hash is a local copy, so we don't need regex_lock */
4696
4697	parser = &iter->parser;
4698	read = trace_get_user(parser, ubuf, cnt, ppos);
4699
4700	if (read >= 0 && trace_parser_loaded(parser) &&
4701	    !trace_parser_cont(parser)) {
4702		ret = ftrace_process_regex(iter, parser->buffer,
4703					   parser->idx, enable);
4704		trace_parser_clear(parser);
4705		if (ret < 0)
4706			goto out;
4707	}
4708
4709	ret = read;
4710 out:
4711	return ret;
4712}
4713
4714ssize_t
4715ftrace_filter_write(struct file *file, const char __user *ubuf,
4716		    size_t cnt, loff_t *ppos)
4717{
4718	return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
4719}
4720
4721ssize_t
4722ftrace_notrace_write(struct file *file, const char __user *ubuf,
4723		     size_t cnt, loff_t *ppos)
4724{
4725	return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
4726}
4727
4728static int
4729ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
4730{
4731	struct ftrace_func_entry *entry;
4732
4733	if (!ftrace_location(ip))
4734		return -EINVAL;
4735
4736	if (remove) {
4737		entry = ftrace_lookup_ip(hash, ip);
4738		if (!entry)
4739			return -ENOENT;
4740		free_hash_entry(hash, entry);
4741		return 0;
4742	}
4743
4744	return add_hash_entry(hash, ip);
4745}
4746
 
 
 
 
 
 
4747static int
4748ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
4749		unsigned long ip, int remove, int reset, int enable)
4750{
4751	struct ftrace_hash **orig_hash;
4752	struct ftrace_hash *hash;
4753	int ret;
4754
 
 
 
 
4755	if (unlikely(ftrace_disabled))
4756		return -ENODEV;
4757
4758	mutex_lock(&ops->func_hash->regex_lock);
4759
4760	if (enable)
4761		orig_hash = &ops->func_hash->filter_hash;
4762	else
4763		orig_hash = &ops->func_hash->notrace_hash;
4764
4765	if (reset)
4766		hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4767	else
4768		hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
4769
 
4770	if (!hash) {
4771		ret = -ENOMEM;
4772		goto out_regex_unlock;
4773	}
4774
 
 
4775	if (buf && !ftrace_match_records(hash, buf, len)) {
4776		ret = -EINVAL;
4777		goto out_regex_unlock;
4778	}
4779	if (ip) {
4780		ret = ftrace_match_addr(hash, ip, remove);
4781		if (ret < 0)
4782			goto out_regex_unlock;
4783	}
4784
4785	mutex_lock(&ftrace_lock);
4786	ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
 
 
 
4787	mutex_unlock(&ftrace_lock);
4788
4789 out_regex_unlock:
4790	mutex_unlock(&ops->func_hash->regex_lock);
4791
4792	free_ftrace_hash(hash);
4793	return ret;
4794}
4795
4796static int
4797ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove,
4798		int reset, int enable)
4799{
4800	return ftrace_set_hash(ops, NULL, 0, ip, remove, reset, enable);
4801}
4802
4803/**
4804 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
4805 * @ops - the ops to set the filter with
4806 * @ip - the address to add to or remove from the filter.
4807 * @remove - non zero to remove the ip from the filter
4808 * @reset - non zero to reset all filters before applying this filter.
4809 *
4810 * Filters denote which functions should be enabled when tracing is enabled
4811 * If @ip is NULL, it failes to update filter.
4812 */
4813int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
4814			 int remove, int reset)
4815{
4816	ftrace_ops_init(ops);
4817	return ftrace_set_addr(ops, ip, remove, reset, 1);
4818}
4819EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
4820
4821/**
4822 * ftrace_ops_set_global_filter - setup ops to use global filters
4823 * @ops - the ops which will use the global filters
4824 *
4825 * ftrace users who need global function trace filtering should call this.
4826 * It can set the global filter only if ops were not initialized before.
4827 */
4828void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
4829{
4830	if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
4831		return;
4832
4833	ftrace_ops_init(ops);
4834	ops->func_hash = &global_ops.local_hash;
4835}
4836EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
4837
4838static int
4839ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4840		 int reset, int enable)
4841{
4842	return ftrace_set_hash(ops, buf, len, 0, 0, reset, enable);
4843}
4844
4845/**
4846 * ftrace_set_filter - set a function to filter on in ftrace
4847 * @ops - the ops to set the filter with
4848 * @buf - the string that holds the function filter text.
4849 * @len - the length of the string.
4850 * @reset - non zero to reset all filters before applying this filter.
4851 *
4852 * Filters denote which functions should be enabled when tracing is enabled.
4853 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4854 */
4855int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
4856		       int len, int reset)
4857{
4858	ftrace_ops_init(ops);
4859	return ftrace_set_regex(ops, buf, len, reset, 1);
4860}
4861EXPORT_SYMBOL_GPL(ftrace_set_filter);
4862
4863/**
4864 * ftrace_set_notrace - set a function to not trace in ftrace
4865 * @ops - the ops to set the notrace filter with
4866 * @buf - the string that holds the function notrace text.
4867 * @len - the length of the string.
4868 * @reset - non zero to reset all filters before applying this filter.
4869 *
4870 * Notrace Filters denote which functions should not be enabled when tracing
4871 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4872 * for tracing.
4873 */
4874int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
4875			int len, int reset)
4876{
4877	ftrace_ops_init(ops);
4878	return ftrace_set_regex(ops, buf, len, reset, 0);
4879}
4880EXPORT_SYMBOL_GPL(ftrace_set_notrace);
4881/**
4882 * ftrace_set_global_filter - set a function to filter on with global tracers
 
4883 * @buf - the string that holds the function filter text.
4884 * @len - the length of the string.
4885 * @reset - non zero to reset all filters before applying this filter.
4886 *
4887 * Filters denote which functions should be enabled when tracing is enabled.
4888 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
4889 */
4890void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
4891{
4892	ftrace_set_regex(&global_ops, buf, len, reset, 1);
4893}
4894EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
4895
4896/**
4897 * ftrace_set_global_notrace - set a function to not trace with global tracers
 
4898 * @buf - the string that holds the function notrace text.
4899 * @len - the length of the string.
4900 * @reset - non zero to reset all filters before applying this filter.
4901 *
4902 * Notrace Filters denote which functions should not be enabled when tracing
4903 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
4904 * for tracing.
4905 */
4906void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
4907{
4908	ftrace_set_regex(&global_ops, buf, len, reset, 0);
4909}
4910EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
4911
4912/*
4913 * command line interface to allow users to set filters on boot up.
4914 */
4915#define FTRACE_FILTER_SIZE		COMMAND_LINE_SIZE
4916static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4917static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
4918
4919/* Used by function selftest to not test if filter is set */
4920bool ftrace_filter_param __initdata;
4921
4922static int __init set_ftrace_notrace(char *str)
4923{
4924	ftrace_filter_param = true;
4925	strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
4926	return 1;
4927}
4928__setup("ftrace_notrace=", set_ftrace_notrace);
4929
4930static int __init set_ftrace_filter(char *str)
4931{
4932	ftrace_filter_param = true;
4933	strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
4934	return 1;
4935}
4936__setup("ftrace_filter=", set_ftrace_filter);
4937
4938#ifdef CONFIG_FUNCTION_GRAPH_TRACER
4939static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
4940static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
4941static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
4942
4943static int __init set_graph_function(char *str)
4944{
4945	strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
4946	return 1;
4947}
4948__setup("ftrace_graph_filter=", set_graph_function);
4949
4950static int __init set_graph_notrace_function(char *str)
4951{
4952	strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
4953	return 1;
4954}
4955__setup("ftrace_graph_notrace=", set_graph_notrace_function);
4956
4957static int __init set_graph_max_depth_function(char *str)
4958{
4959	if (!str)
4960		return 0;
4961	fgraph_max_depth = simple_strtoul(str, NULL, 0);
4962	return 1;
4963}
4964__setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
4965
4966static void __init set_ftrace_early_graph(char *buf, int enable)
4967{
4968	int ret;
4969	char *func;
4970	struct ftrace_hash *hash;
4971
4972	hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4973	if (WARN_ON(!hash))
4974		return;
4975
4976	while (buf) {
4977		func = strsep(&buf, ",");
4978		/* we allow only one expression at a time */
4979		ret = ftrace_graph_set_hash(hash, func);
 
4980		if (ret)
4981			printk(KERN_DEBUG "ftrace: function %s not "
4982					  "traceable\n", func);
4983	}
4984
4985	if (enable)
4986		ftrace_graph_hash = hash;
4987	else
4988		ftrace_graph_notrace_hash = hash;
4989}
4990#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
4991
4992void __init
4993ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
4994{
4995	char *func;
4996
4997	ftrace_ops_init(ops);
4998
4999	while (buf) {
5000		func = strsep(&buf, ",");
5001		ftrace_set_regex(ops, func, strlen(func), 0, enable);
5002	}
5003}
5004
5005static void __init set_ftrace_early_filters(void)
5006{
5007	if (ftrace_filter_buf[0])
5008		ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5009	if (ftrace_notrace_buf[0])
5010		ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5011#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5012	if (ftrace_graph_buf[0])
5013		set_ftrace_early_graph(ftrace_graph_buf, 1);
5014	if (ftrace_graph_notrace_buf[0])
5015		set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5016#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5017}
5018
5019int ftrace_regex_release(struct inode *inode, struct file *file)
5020{
5021	struct seq_file *m = (struct seq_file *)file->private_data;
5022	struct ftrace_iterator *iter;
5023	struct ftrace_hash **orig_hash;
5024	struct trace_parser *parser;
5025	int filter_hash;
5026	int ret;
5027
5028	if (file->f_mode & FMODE_READ) {
5029		iter = m->private;
5030		seq_release(inode, file);
5031	} else
5032		iter = file->private_data;
5033
5034	parser = &iter->parser;
5035	if (trace_parser_loaded(parser)) {
 
5036		ftrace_match_records(iter->hash, parser->buffer, parser->idx);
5037	}
5038
5039	trace_parser_put(parser);
5040
5041	mutex_lock(&iter->ops->func_hash->regex_lock);
5042
5043	if (file->f_mode & FMODE_WRITE) {
5044		filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5045
5046		if (filter_hash) {
5047			orig_hash = &iter->ops->func_hash->filter_hash;
5048			if (iter->tr && !list_empty(&iter->tr->mod_trace))
5049				iter->hash->flags |= FTRACE_HASH_FL_MOD;
5050		} else
5051			orig_hash = &iter->ops->func_hash->notrace_hash;
5052
5053		mutex_lock(&ftrace_lock);
5054		ret = ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5055						      iter->hash, filter_hash);
 
 
 
5056		mutex_unlock(&ftrace_lock);
5057	} else {
5058		/* For read only, the hash is the ops hash */
5059		iter->hash = NULL;
5060	}
5061
5062	mutex_unlock(&iter->ops->func_hash->regex_lock);
5063	free_ftrace_hash(iter->hash);
5064	if (iter->tr)
5065		trace_array_put(iter->tr);
5066	kfree(iter);
5067
5068	return 0;
5069}
5070
5071static const struct file_operations ftrace_avail_fops = {
5072	.open = ftrace_avail_open,
5073	.read = seq_read,
5074	.llseek = seq_lseek,
5075	.release = seq_release_private,
5076};
5077
5078static const struct file_operations ftrace_enabled_fops = {
5079	.open = ftrace_enabled_open,
5080	.read = seq_read,
5081	.llseek = seq_lseek,
5082	.release = seq_release_private,
5083};
5084
5085static const struct file_operations ftrace_filter_fops = {
5086	.open = ftrace_filter_open,
5087	.read = seq_read,
5088	.write = ftrace_filter_write,
5089	.llseek = tracing_lseek,
5090	.release = ftrace_regex_release,
5091};
5092
5093static const struct file_operations ftrace_notrace_fops = {
5094	.open = ftrace_notrace_open,
5095	.read = seq_read,
5096	.write = ftrace_notrace_write,
5097	.llseek = tracing_lseek,
5098	.release = ftrace_regex_release,
5099};
5100
5101#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5102
5103static DEFINE_MUTEX(graph_lock);
5104
5105struct ftrace_hash *ftrace_graph_hash = EMPTY_HASH;
5106struct ftrace_hash *ftrace_graph_notrace_hash = EMPTY_HASH;
5107
5108enum graph_filter_type {
5109	GRAPH_FILTER_NOTRACE	= 0,
5110	GRAPH_FILTER_FUNCTION,
5111};
5112
5113#define FTRACE_GRAPH_EMPTY	((void *)1)
5114
5115struct ftrace_graph_data {
5116	struct ftrace_hash		*hash;
5117	struct ftrace_func_entry	*entry;
5118	int				idx;   /* for hash table iteration */
5119	enum graph_filter_type		type;
5120	struct ftrace_hash		*new_hash;
5121	const struct seq_operations	*seq_ops;
5122	struct trace_parser		parser;
5123};
5124
5125static void *
5126__g_next(struct seq_file *m, loff_t *pos)
5127{
5128	struct ftrace_graph_data *fgd = m->private;
5129	struct ftrace_func_entry *entry = fgd->entry;
5130	struct hlist_head *head;
5131	int i, idx = fgd->idx;
5132
5133	if (*pos >= fgd->hash->count)
5134		return NULL;
5135
5136	if (entry) {
5137		hlist_for_each_entry_continue(entry, hlist) {
5138			fgd->entry = entry;
5139			return entry;
5140		}
5141
5142		idx++;
5143	}
5144
5145	for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
5146		head = &fgd->hash->buckets[i];
5147		hlist_for_each_entry(entry, head, hlist) {
5148			fgd->entry = entry;
5149			fgd->idx = i;
5150			return entry;
5151		}
5152	}
5153	return NULL;
5154}
5155
5156static void *
5157g_next(struct seq_file *m, void *v, loff_t *pos)
5158{
5159	(*pos)++;
5160	return __g_next(m, pos);
5161}
5162
5163static void *g_start(struct seq_file *m, loff_t *pos)
5164{
5165	struct ftrace_graph_data *fgd = m->private;
5166
5167	mutex_lock(&graph_lock);
5168
5169	if (fgd->type == GRAPH_FILTER_FUNCTION)
5170		fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5171					lockdep_is_held(&graph_lock));
5172	else
5173		fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5174					lockdep_is_held(&graph_lock));
5175
5176	/* Nothing, tell g_show to print all functions are enabled */
5177	if (ftrace_hash_empty(fgd->hash) && !*pos)
5178		return FTRACE_GRAPH_EMPTY;
5179
5180	fgd->idx = 0;
5181	fgd->entry = NULL;
5182	return __g_next(m, pos);
5183}
5184
5185static void g_stop(struct seq_file *m, void *p)
5186{
5187	mutex_unlock(&graph_lock);
5188}
5189
5190static int g_show(struct seq_file *m, void *v)
5191{
5192	struct ftrace_func_entry *entry = v;
5193
5194	if (!entry)
5195		return 0;
5196
5197	if (entry == FTRACE_GRAPH_EMPTY) {
5198		struct ftrace_graph_data *fgd = m->private;
5199
5200		if (fgd->type == GRAPH_FILTER_FUNCTION)
5201			seq_puts(m, "#### all functions enabled ####\n");
5202		else
5203			seq_puts(m, "#### no functions disabled ####\n");
5204		return 0;
5205	}
5206
5207	seq_printf(m, "%ps\n", (void *)entry->ip);
5208
5209	return 0;
5210}
5211
5212static const struct seq_operations ftrace_graph_seq_ops = {
5213	.start = g_start,
5214	.next = g_next,
5215	.stop = g_stop,
5216	.show = g_show,
5217};
5218
5219static int
5220__ftrace_graph_open(struct inode *inode, struct file *file,
5221		    struct ftrace_graph_data *fgd)
5222{
5223	int ret;
5224	struct ftrace_hash *new_hash = NULL;
5225
5226	ret = security_locked_down(LOCKDOWN_TRACEFS);
5227	if (ret)
5228		return ret;
5229
5230	if (file->f_mode & FMODE_WRITE) {
5231		const int size_bits = FTRACE_HASH_DEFAULT_BITS;
5232
5233		if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
5234			return -ENOMEM;
5235
5236		if (file->f_flags & O_TRUNC)
5237			new_hash = alloc_ftrace_hash(size_bits);
5238		else
5239			new_hash = alloc_and_copy_ftrace_hash(size_bits,
5240							      fgd->hash);
5241		if (!new_hash) {
5242			ret = -ENOMEM;
5243			goto out;
5244		}
5245	}
 
5246
5247	if (file->f_mode & FMODE_READ) {
5248		ret = seq_open(file, &ftrace_graph_seq_ops);
5249		if (!ret) {
5250			struct seq_file *m = file->private_data;
5251			m->private = fgd;
5252		} else {
5253			/* Failed */
5254			free_ftrace_hash(new_hash);
5255			new_hash = NULL;
5256		}
5257	} else
5258		file->private_data = fgd;
5259
5260out:
5261	if (ret < 0 && file->f_mode & FMODE_WRITE)
5262		trace_parser_put(&fgd->parser);
5263
5264	fgd->new_hash = new_hash;
5265
5266	/*
5267	 * All uses of fgd->hash must be taken with the graph_lock
5268	 * held. The graph_lock is going to be released, so force
5269	 * fgd->hash to be reinitialized when it is taken again.
5270	 */
5271	fgd->hash = NULL;
5272
5273	return ret;
5274}
5275
5276static int
5277ftrace_graph_open(struct inode *inode, struct file *file)
5278{
5279	struct ftrace_graph_data *fgd;
5280	int ret;
5281
5282	if (unlikely(ftrace_disabled))
5283		return -ENODEV;
5284
5285	fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5286	if (fgd == NULL)
5287		return -ENOMEM;
5288
5289	mutex_lock(&graph_lock);
5290
5291	fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
5292					lockdep_is_held(&graph_lock));
5293	fgd->type = GRAPH_FILTER_FUNCTION;
5294	fgd->seq_ops = &ftrace_graph_seq_ops;
5295
5296	ret = __ftrace_graph_open(inode, file, fgd);
5297	if (ret < 0)
5298		kfree(fgd);
5299
5300	mutex_unlock(&graph_lock);
5301	return ret;
5302}
5303
5304static int
5305ftrace_graph_notrace_open(struct inode *inode, struct file *file)
5306{
5307	struct ftrace_graph_data *fgd;
5308	int ret;
5309
5310	if (unlikely(ftrace_disabled))
5311		return -ENODEV;
5312
5313	fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
5314	if (fgd == NULL)
5315		return -ENOMEM;
5316
5317	mutex_lock(&graph_lock);
5318
5319	fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5320					lockdep_is_held(&graph_lock));
5321	fgd->type = GRAPH_FILTER_NOTRACE;
5322	fgd->seq_ops = &ftrace_graph_seq_ops;
5323
5324	ret = __ftrace_graph_open(inode, file, fgd);
5325	if (ret < 0)
5326		kfree(fgd);
5327
5328	mutex_unlock(&graph_lock);
5329	return ret;
5330}
5331
5332static int
5333ftrace_graph_release(struct inode *inode, struct file *file)
5334{
5335	struct ftrace_graph_data *fgd;
5336	struct ftrace_hash *old_hash, *new_hash;
5337	struct trace_parser *parser;
5338	int ret = 0;
5339
5340	if (file->f_mode & FMODE_READ) {
5341		struct seq_file *m = file->private_data;
5342
5343		fgd = m->private;
5344		seq_release(inode, file);
5345	} else {
5346		fgd = file->private_data;
5347	}
5348
5349
5350	if (file->f_mode & FMODE_WRITE) {
5351
5352		parser = &fgd->parser;
5353
5354		if (trace_parser_loaded((parser))) {
5355			ret = ftrace_graph_set_hash(fgd->new_hash,
5356						    parser->buffer);
5357		}
5358
5359		trace_parser_put(parser);
5360
5361		new_hash = __ftrace_hash_move(fgd->new_hash);
5362		if (!new_hash) {
5363			ret = -ENOMEM;
5364			goto out;
5365		}
5366
5367		mutex_lock(&graph_lock);
5368
5369		if (fgd->type == GRAPH_FILTER_FUNCTION) {
5370			old_hash = rcu_dereference_protected(ftrace_graph_hash,
5371					lockdep_is_held(&graph_lock));
5372			rcu_assign_pointer(ftrace_graph_hash, new_hash);
5373		} else {
5374			old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
5375					lockdep_is_held(&graph_lock));
5376			rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
5377		}
5378
5379		mutex_unlock(&graph_lock);
5380
5381		/* Wait till all users are no longer using the old hash */
5382		synchronize_rcu();
5383
5384		free_ftrace_hash(old_hash);
5385	}
5386
5387 out:
5388	free_ftrace_hash(fgd->new_hash);
5389	kfree(fgd);
5390
5391	return ret;
5392}
5393
5394static int
5395ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
5396{
5397	struct ftrace_glob func_g;
5398	struct dyn_ftrace *rec;
5399	struct ftrace_page *pg;
5400	struct ftrace_func_entry *entry;
5401	int fail = 1;
5402	int not;
 
 
 
5403
5404	/* decode regex */
5405	func_g.type = filter_parse_regex(buffer, strlen(buffer),
5406					 &func_g.search, &not);
 
5407
5408	func_g.len = strlen(func_g.search);
5409
5410	mutex_lock(&ftrace_lock);
5411
5412	if (unlikely(ftrace_disabled)) {
5413		mutex_unlock(&ftrace_lock);
5414		return -ENODEV;
5415	}
5416
5417	do_for_each_ftrace_rec(pg, rec) {
5418
5419		if (rec->flags & FTRACE_FL_DISABLED)
5420			continue;
5421
5422		if (ftrace_match_record(rec, &func_g, NULL, 0)) {
5423			entry = ftrace_lookup_ip(hash, rec->ip);
 
 
 
 
5424
5425			if (!not) {
5426				fail = 0;
5427
5428				if (entry)
5429					continue;
5430				if (add_hash_entry(hash, rec->ip) < 0)
5431					goto out;
5432			} else {
5433				if (entry) {
5434					free_hash_entry(hash, entry);
 
5435					fail = 0;
5436				}
5437			}
5438		}
5439	} while_for_each_ftrace_rec();
5440out:
5441	mutex_unlock(&ftrace_lock);
5442
5443	if (fail)
5444		return -EINVAL;
5445
5446	return 0;
5447}
5448
5449static ssize_t
5450ftrace_graph_write(struct file *file, const char __user *ubuf,
5451		   size_t cnt, loff_t *ppos)
5452{
 
5453	ssize_t read, ret = 0;
5454	struct ftrace_graph_data *fgd = file->private_data;
5455	struct trace_parser *parser;
5456
5457	if (!cnt)
5458		return 0;
5459
5460	/* Read mode uses seq functions */
5461	if (file->f_mode & FMODE_READ) {
5462		struct seq_file *m = file->private_data;
5463		fgd = m->private;
5464	}
5465
5466	parser = &fgd->parser;
5467
5468	read = trace_get_user(parser, ubuf, cnt, ppos);
 
5469
5470	if (read >= 0 && trace_parser_loaded(parser) &&
5471	    !trace_parser_cont(parser)) {
5472
5473		ret = ftrace_graph_set_hash(fgd->new_hash,
5474					    parser->buffer);
5475		trace_parser_clear(parser);
 
 
5476	}
5477
5478	if (!ret)
5479		ret = read;
5480
 
 
5481	return ret;
5482}
5483
5484static const struct file_operations ftrace_graph_fops = {
5485	.open		= ftrace_graph_open,
5486	.read		= seq_read,
5487	.write		= ftrace_graph_write,
5488	.llseek		= tracing_lseek,
5489	.release	= ftrace_graph_release,
5490};
5491
5492static const struct file_operations ftrace_graph_notrace_fops = {
5493	.open		= ftrace_graph_notrace_open,
5494	.read		= seq_read,
5495	.write		= ftrace_graph_write,
5496	.llseek		= tracing_lseek,
5497	.release	= ftrace_graph_release,
5498};
5499#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5500
5501void ftrace_create_filter_files(struct ftrace_ops *ops,
5502				struct dentry *parent)
5503{
5504
5505	trace_create_file("set_ftrace_filter", 0644, parent,
5506			  ops, &ftrace_filter_fops);
5507
5508	trace_create_file("set_ftrace_notrace", 0644, parent,
5509			  ops, &ftrace_notrace_fops);
5510}
5511
5512/*
5513 * The name "destroy_filter_files" is really a misnomer. Although
5514 * in the future, it may actually delete the files, but this is
5515 * really intended to make sure the ops passed in are disabled
5516 * and that when this function returns, the caller is free to
5517 * free the ops.
5518 *
5519 * The "destroy" name is only to match the "create" name that this
5520 * should be paired with.
5521 */
5522void ftrace_destroy_filter_files(struct ftrace_ops *ops)
5523{
5524	mutex_lock(&ftrace_lock);
5525	if (ops->flags & FTRACE_OPS_FL_ENABLED)
5526		ftrace_shutdown(ops, 0);
5527	ops->flags |= FTRACE_OPS_FL_DELETED;
5528	ftrace_free_filter(ops);
5529	mutex_unlock(&ftrace_lock);
5530}
5531
5532static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
5533{
5534
5535	trace_create_file("available_filter_functions", 0444,
5536			d_tracer, NULL, &ftrace_avail_fops);
5537
5538	trace_create_file("enabled_functions", 0444,
5539			d_tracer, NULL, &ftrace_enabled_fops);
5540
5541	ftrace_create_filter_files(&global_ops, d_tracer);
5542
5543#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5544	trace_create_file("set_graph_function", 0644, d_tracer,
5545				    NULL,
5546				    &ftrace_graph_fops);
5547	trace_create_file("set_graph_notrace", 0644, d_tracer,
5548				    NULL,
5549				    &ftrace_graph_notrace_fops);
5550#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5551
5552	return 0;
5553}
5554
5555static int ftrace_cmp_ips(const void *a, const void *b)
5556{
5557	const unsigned long *ipa = a;
5558	const unsigned long *ipb = b;
5559
5560	if (*ipa > *ipb)
5561		return 1;
5562	if (*ipa < *ipb)
5563		return -1;
5564	return 0;
5565}
5566
 
 
 
 
 
 
 
 
 
 
 
5567static int ftrace_process_locs(struct module *mod,
5568			       unsigned long *start,
5569			       unsigned long *end)
5570{
5571	struct ftrace_page *start_pg;
5572	struct ftrace_page *pg;
5573	struct dyn_ftrace *rec;
5574	unsigned long count;
5575	unsigned long *p;
5576	unsigned long addr;
5577	unsigned long flags = 0; /* Shut up gcc */
5578	int ret = -ENOMEM;
5579
5580	count = end - start;
5581
5582	if (!count)
5583		return 0;
5584
5585	sort(start, count, sizeof(*start),
5586	     ftrace_cmp_ips, NULL);
5587
5588	start_pg = ftrace_allocate_pages(count);
5589	if (!start_pg)
5590		return -ENOMEM;
5591
5592	mutex_lock(&ftrace_lock);
5593
5594	/*
5595	 * Core and each module needs their own pages, as
5596	 * modules will free them when they are removed.
5597	 * Force a new page to be allocated for modules.
5598	 */
5599	if (!mod) {
5600		WARN_ON(ftrace_pages || ftrace_pages_start);
5601		/* First initialization */
5602		ftrace_pages = ftrace_pages_start = start_pg;
5603	} else {
5604		if (!ftrace_pages)
5605			goto out;
5606
5607		if (WARN_ON(ftrace_pages->next)) {
5608			/* Hmm, we have free pages? */
5609			while (ftrace_pages->next)
5610				ftrace_pages = ftrace_pages->next;
5611		}
5612
5613		ftrace_pages->next = start_pg;
5614	}
5615
5616	p = start;
5617	pg = start_pg;
5618	while (p < end) {
5619		addr = ftrace_call_adjust(*p++);
5620		/*
5621		 * Some architecture linkers will pad between
5622		 * the different mcount_loc sections of different
5623		 * object files to satisfy alignments.
5624		 * Skip any NULL pointers.
5625		 */
5626		if (!addr)
5627			continue;
5628
5629		if (pg->index == pg->size) {
5630			/* We should have allocated enough */
5631			if (WARN_ON(!pg->next))
5632				break;
5633			pg = pg->next;
5634		}
5635
5636		rec = &pg->records[pg->index++];
5637		rec->ip = addr;
5638	}
5639
5640	/* We should have used all pages */
5641	WARN_ON(pg->next);
5642
5643	/* Assign the last page to ftrace_pages */
5644	ftrace_pages = pg;
5645
5646	/*
5647	 * We only need to disable interrupts on start up
5648	 * because we are modifying code that an interrupt
5649	 * may execute, and the modification is not atomic.
5650	 * But for modules, nothing runs the code we modify
5651	 * until we are finished with it, and there's no
5652	 * reason to cause large interrupt latencies while we do it.
5653	 */
5654	if (!mod)
5655		local_irq_save(flags);
5656	ftrace_update_code(mod, start_pg);
5657	if (!mod)
5658		local_irq_restore(flags);
5659	ret = 0;
5660 out:
5661	mutex_unlock(&ftrace_lock);
5662
5663	return ret;
5664}
5665
5666struct ftrace_mod_func {
5667	struct list_head	list;
5668	char			*name;
5669	unsigned long		ip;
5670	unsigned int		size;
5671};
5672
5673struct ftrace_mod_map {
5674	struct rcu_head		rcu;
5675	struct list_head	list;
5676	struct module		*mod;
5677	unsigned long		start_addr;
5678	unsigned long		end_addr;
5679	struct list_head	funcs;
5680	unsigned int		num_funcs;
5681};
5682
5683#ifdef CONFIG_MODULES
5684
5685#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
5686
5687static LIST_HEAD(ftrace_mod_maps);
5688
5689static int referenced_filters(struct dyn_ftrace *rec)
5690{
5691	struct ftrace_ops *ops;
5692	int cnt = 0;
5693
5694	for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
5695		if (ops_references_rec(ops, rec))
5696		    cnt++;
5697	}
5698
5699	return cnt;
5700}
5701
5702static void
5703clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
5704{
5705	struct ftrace_func_entry *entry;
5706	struct dyn_ftrace *rec;
5707	int i;
5708
5709	if (ftrace_hash_empty(hash))
5710		return;
5711
5712	for (i = 0; i < pg->index; i++) {
5713		rec = &pg->records[i];
5714		entry = __ftrace_lookup_ip(hash, rec->ip);
5715		/*
5716		 * Do not allow this rec to match again.
5717		 * Yeah, it may waste some memory, but will be removed
5718		 * if/when the hash is modified again.
5719		 */
5720		if (entry)
5721			entry->ip = 0;
5722	}
5723}
5724
5725/* Clear any records from hashs */
5726static void clear_mod_from_hashes(struct ftrace_page *pg)
5727{
5728	struct trace_array *tr;
5729
5730	mutex_lock(&trace_types_lock);
5731	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
5732		if (!tr->ops || !tr->ops->func_hash)
5733			continue;
5734		mutex_lock(&tr->ops->func_hash->regex_lock);
5735		clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
5736		clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
5737		mutex_unlock(&tr->ops->func_hash->regex_lock);
5738	}
5739	mutex_unlock(&trace_types_lock);
5740}
5741
5742static void ftrace_free_mod_map(struct rcu_head *rcu)
5743{
5744	struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
5745	struct ftrace_mod_func *mod_func;
5746	struct ftrace_mod_func *n;
5747
5748	/* All the contents of mod_map are now not visible to readers */
5749	list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
5750		kfree(mod_func->name);
5751		list_del(&mod_func->list);
5752		kfree(mod_func);
5753	}
5754
5755	kfree(mod_map);
5756}
5757
5758void ftrace_release_mod(struct module *mod)
5759{
5760	struct ftrace_mod_map *mod_map;
5761	struct ftrace_mod_map *n;
5762	struct dyn_ftrace *rec;
5763	struct ftrace_page **last_pg;
5764	struct ftrace_page *tmp_page = NULL;
5765	struct ftrace_page *pg;
5766	int order;
5767
5768	mutex_lock(&ftrace_lock);
5769
5770	if (ftrace_disabled)
5771		goto out_unlock;
5772
5773	list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
5774		if (mod_map->mod == mod) {
5775			list_del_rcu(&mod_map->list);
5776			call_rcu(&mod_map->rcu, ftrace_free_mod_map);
5777			break;
5778		}
5779	}
5780
5781	/*
5782	 * Each module has its own ftrace_pages, remove
5783	 * them from the list.
5784	 */
5785	last_pg = &ftrace_pages_start;
5786	for (pg = ftrace_pages_start; pg; pg = *last_pg) {
5787		rec = &pg->records[0];
5788		if (within_module_core(rec->ip, mod) ||
5789		    within_module_init(rec->ip, mod)) {
5790			/*
5791			 * As core pages are first, the first
5792			 * page should never be a module page.
5793			 */
5794			if (WARN_ON(pg == ftrace_pages_start))
5795				goto out_unlock;
5796
5797			/* Check if we are deleting the last page */
5798			if (pg == ftrace_pages)
5799				ftrace_pages = next_to_ftrace_page(last_pg);
5800
5801			ftrace_update_tot_cnt -= pg->index;
5802			*last_pg = pg->next;
5803
5804			pg->next = tmp_page;
5805			tmp_page = pg;
5806		} else
5807			last_pg = &pg->next;
5808	}
5809 out_unlock:
5810	mutex_unlock(&ftrace_lock);
5811
5812	for (pg = tmp_page; pg; pg = tmp_page) {
5813
5814		/* Needs to be called outside of ftrace_lock */
5815		clear_mod_from_hashes(pg);
5816
5817		order = get_count_order(pg->size / ENTRIES_PER_PAGE);
5818		free_pages((unsigned long)pg->records, order);
5819		tmp_page = pg->next;
5820		kfree(pg);
5821	}
5822}
5823
5824void ftrace_module_enable(struct module *mod)
5825{
5826	struct dyn_ftrace *rec;
5827	struct ftrace_page *pg;
5828
5829	mutex_lock(&ftrace_lock);
5830
5831	if (ftrace_disabled)
5832		goto out_unlock;
5833
5834	/*
5835	 * If the tracing is enabled, go ahead and enable the record.
5836	 *
5837	 * The reason not to enable the record immediately is the
5838	 * inherent check of ftrace_make_nop/ftrace_make_call for
5839	 * correct previous instructions.  Making first the NOP
5840	 * conversion puts the module to the correct state, thus
5841	 * passing the ftrace_make_call check.
5842	 *
5843	 * We also delay this to after the module code already set the
5844	 * text to read-only, as we now need to set it back to read-write
5845	 * so that we can modify the text.
5846	 */
5847	if (ftrace_start_up)
5848		ftrace_arch_code_modify_prepare();
5849
5850	do_for_each_ftrace_rec(pg, rec) {
5851		int cnt;
5852		/*
5853		 * do_for_each_ftrace_rec() is a double loop.
5854		 * module text shares the pg. If a record is
5855		 * not part of this module, then skip this pg,
5856		 * which the "break" will do.
5857		 */
5858		if (!within_module_core(rec->ip, mod) &&
5859		    !within_module_init(rec->ip, mod))
5860			break;
5861
5862		cnt = 0;
5863
5864		/*
5865		 * When adding a module, we need to check if tracers are
5866		 * currently enabled and if they are, and can trace this record,
5867		 * we need to enable the module functions as well as update the
5868		 * reference counts for those function records.
5869		 */
5870		if (ftrace_start_up)
5871			cnt += referenced_filters(rec);
5872
5873		/* This clears FTRACE_FL_DISABLED */
5874		rec->flags = cnt;
5875
5876		if (ftrace_start_up && cnt) {
5877			int failed = __ftrace_replace_code(rec, 1);
5878			if (failed) {
5879				ftrace_bug(failed, rec);
5880				goto out_loop;
5881			}
5882		}
5883
5884	} while_for_each_ftrace_rec();
5885
5886 out_loop:
5887	if (ftrace_start_up)
5888		ftrace_arch_code_modify_post_process();
5889
5890 out_unlock:
5891	mutex_unlock(&ftrace_lock);
5892
5893	process_cached_mods(mod->name);
5894}
5895
5896void ftrace_module_init(struct module *mod)
 
5897{
5898	if (ftrace_disabled || !mod->num_ftrace_callsites)
5899		return;
5900
5901	ftrace_process_locs(mod, mod->ftrace_callsites,
5902			    mod->ftrace_callsites + mod->num_ftrace_callsites);
5903}
5904
5905static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
5906				struct dyn_ftrace *rec)
5907{
5908	struct ftrace_mod_func *mod_func;
5909	unsigned long symsize;
5910	unsigned long offset;
5911	char str[KSYM_SYMBOL_LEN];
5912	char *modname;
5913	const char *ret;
5914
5915	ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
5916	if (!ret)
5917		return;
5918
5919	mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
5920	if (!mod_func)
5921		return;
5922
5923	mod_func->name = kstrdup(str, GFP_KERNEL);
5924	if (!mod_func->name) {
5925		kfree(mod_func);
5926		return;
5927	}
5928
5929	mod_func->ip = rec->ip - offset;
5930	mod_func->size = symsize;
5931
5932	mod_map->num_funcs++;
5933
5934	list_add_rcu(&mod_func->list, &mod_map->funcs);
5935}
5936
5937static struct ftrace_mod_map *
5938allocate_ftrace_mod_map(struct module *mod,
5939			unsigned long start, unsigned long end)
5940{
5941	struct ftrace_mod_map *mod_map;
5942
5943	mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
5944	if (!mod_map)
5945		return NULL;
5946
5947	mod_map->mod = mod;
5948	mod_map->start_addr = start;
5949	mod_map->end_addr = end;
5950	mod_map->num_funcs = 0;
5951
5952	INIT_LIST_HEAD_RCU(&mod_map->funcs);
5953
5954	list_add_rcu(&mod_map->list, &ftrace_mod_maps);
5955
5956	return mod_map;
5957}
5958
5959static const char *
5960ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
5961			   unsigned long addr, unsigned long *size,
5962			   unsigned long *off, char *sym)
5963{
5964	struct ftrace_mod_func *found_func =  NULL;
5965	struct ftrace_mod_func *mod_func;
5966
5967	list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
5968		if (addr >= mod_func->ip &&
5969		    addr < mod_func->ip + mod_func->size) {
5970			found_func = mod_func;
5971			break;
5972		}
5973	}
5974
5975	if (found_func) {
5976		if (size)
5977			*size = found_func->size;
5978		if (off)
5979			*off = addr - found_func->ip;
5980		if (sym)
5981			strlcpy(sym, found_func->name, KSYM_NAME_LEN);
5982
5983		return found_func->name;
5984	}
5985
5986	return NULL;
5987}
5988
5989const char *
5990ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
5991		   unsigned long *off, char **modname, char *sym)
5992{
5993	struct ftrace_mod_map *mod_map;
5994	const char *ret = NULL;
5995
5996	/* mod_map is freed via call_rcu() */
5997	preempt_disable();
5998	list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
5999		ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
6000		if (ret) {
6001			if (modname)
6002				*modname = mod_map->mod->name;
6003			break;
6004		}
6005	}
6006	preempt_enable();
6007
6008	return ret;
6009}
6010
6011int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
6012			   char *type, char *name,
6013			   char *module_name, int *exported)
6014{
6015	struct ftrace_mod_map *mod_map;
6016	struct ftrace_mod_func *mod_func;
6017
6018	preempt_disable();
6019	list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
6020
6021		if (symnum >= mod_map->num_funcs) {
6022			symnum -= mod_map->num_funcs;
6023			continue;
6024		}
6025
6026		list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6027			if (symnum > 1) {
6028				symnum--;
6029				continue;
6030			}
6031
6032			*value = mod_func->ip;
6033			*type = 'T';
6034			strlcpy(name, mod_func->name, KSYM_NAME_LEN);
6035			strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
6036			*exported = 1;
6037			preempt_enable();
6038			return 0;
6039		}
6040		WARN_ON(1);
6041		break;
6042	}
6043	preempt_enable();
6044	return -ERANGE;
6045}
6046
6047#else
6048static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6049				struct dyn_ftrace *rec) { }
6050static inline struct ftrace_mod_map *
6051allocate_ftrace_mod_map(struct module *mod,
6052			unsigned long start, unsigned long end)
6053{
6054	return NULL;
6055}
6056#endif /* CONFIG_MODULES */
6057
6058struct ftrace_init_func {
6059	struct list_head list;
6060	unsigned long ip;
6061};
6062
6063/* Clear any init ips from hashes */
6064static void
6065clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
6066{
6067	struct ftrace_func_entry *entry;
6068
6069	entry = ftrace_lookup_ip(hash, func->ip);
6070	/*
6071	 * Do not allow this rec to match again.
6072	 * Yeah, it may waste some memory, but will be removed
6073	 * if/when the hash is modified again.
6074	 */
6075	if (entry)
6076		entry->ip = 0;
6077}
6078
6079static void
6080clear_func_from_hashes(struct ftrace_init_func *func)
6081{
6082	struct trace_array *tr;
6083
6084	mutex_lock(&trace_types_lock);
6085	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6086		if (!tr->ops || !tr->ops->func_hash)
6087			continue;
6088		mutex_lock(&tr->ops->func_hash->regex_lock);
6089		clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
6090		clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
6091		mutex_unlock(&tr->ops->func_hash->regex_lock);
6092	}
6093	mutex_unlock(&trace_types_lock);
6094}
6095
6096static void add_to_clear_hash_list(struct list_head *clear_list,
6097				   struct dyn_ftrace *rec)
6098{
6099	struct ftrace_init_func *func;
6100
6101	func = kmalloc(sizeof(*func), GFP_KERNEL);
6102	if (!func) {
6103		WARN_ONCE(1, "alloc failure, ftrace filter could be stale\n");
6104		return;
6105	}
6106
6107	func->ip = rec->ip;
6108	list_add(&func->list, clear_list);
6109}
6110
6111void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
6112{
6113	unsigned long start = (unsigned long)(start_ptr);
6114	unsigned long end = (unsigned long)(end_ptr);
6115	struct ftrace_page **last_pg = &ftrace_pages_start;
6116	struct ftrace_page *pg;
6117	struct dyn_ftrace *rec;
6118	struct dyn_ftrace key;
6119	struct ftrace_mod_map *mod_map = NULL;
6120	struct ftrace_init_func *func, *func_next;
6121	struct list_head clear_hash;
6122	int order;
6123
6124	INIT_LIST_HEAD(&clear_hash);
6125
6126	key.ip = start;
6127	key.flags = end;	/* overload flags, as it is unsigned long */
6128
6129	mutex_lock(&ftrace_lock);
6130
6131	/*
6132	 * If we are freeing module init memory, then check if
6133	 * any tracer is active. If so, we need to save a mapping of
6134	 * the module functions being freed with the address.
6135	 */
6136	if (mod && ftrace_ops_list != &ftrace_list_end)
6137		mod_map = allocate_ftrace_mod_map(mod, start, end);
6138
6139	for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
6140		if (end < pg->records[0].ip ||
6141		    start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
6142			continue;
6143 again:
6144		rec = bsearch(&key, pg->records, pg->index,
6145			      sizeof(struct dyn_ftrace),
6146			      ftrace_cmp_recs);
6147		if (!rec)
6148			continue;
6149
6150		/* rec will be cleared from hashes after ftrace_lock unlock */
6151		add_to_clear_hash_list(&clear_hash, rec);
6152
6153		if (mod_map)
6154			save_ftrace_mod_rec(mod_map, rec);
6155
6156		pg->index--;
6157		ftrace_update_tot_cnt--;
6158		if (!pg->index) {
6159			*last_pg = pg->next;
6160			order = get_count_order(pg->size / ENTRIES_PER_PAGE);
6161			free_pages((unsigned long)pg->records, order);
6162			kfree(pg);
6163			pg = container_of(last_pg, struct ftrace_page, next);
6164			if (!(*last_pg))
6165				ftrace_pages = pg;
6166			continue;
6167		}
6168		memmove(rec, rec + 1,
6169			(pg->index - (rec - pg->records)) * sizeof(*rec));
6170		/* More than one function may be in this block */
6171		goto again;
6172	}
6173	mutex_unlock(&ftrace_lock);
6174
6175	list_for_each_entry_safe(func, func_next, &clear_hash, list) {
6176		clear_func_from_hashes(func);
6177		kfree(func);
6178	}
6179}
6180
6181void __init ftrace_free_init_mem(void)
6182{
6183	void *start = (void *)(&__init_begin);
6184	void *end = (void *)(&__init_end);
6185
6186	ftrace_free_mem(NULL, start, end);
6187}
6188
6189void __init ftrace_init(void)
6190{
6191	extern unsigned long __start_mcount_loc[];
6192	extern unsigned long __stop_mcount_loc[];
6193	unsigned long count, flags;
6194	int ret;
6195
6196	local_irq_save(flags);
6197	ret = ftrace_dyn_arch_init();
6198	local_irq_restore(flags);
6199	if (ret)
6200		goto failed;
6201
6202	count = __stop_mcount_loc - __start_mcount_loc;
6203	if (!count) {
6204		pr_info("ftrace: No functions to be traced?\n");
6205		goto failed;
6206	}
6207
6208	pr_info("ftrace: allocating %ld entries in %ld pages\n",
6209		count, count / ENTRIES_PER_PAGE + 1);
6210
6211	last_ftrace_enabled = ftrace_enabled = 1;
6212
6213	ret = ftrace_process_locs(NULL,
6214				  __start_mcount_loc,
6215				  __stop_mcount_loc);
6216
 
 
 
 
6217	set_ftrace_early_filters();
6218
6219	return;
6220 failed:
6221	ftrace_disabled = 1;
6222}
6223
6224/* Do nothing if arch does not support this */
6225void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
6226{
6227}
6228
6229static void ftrace_update_trampoline(struct ftrace_ops *ops)
6230{
6231	arch_ftrace_update_trampoline(ops);
6232}
6233
6234void ftrace_init_trace_array(struct trace_array *tr)
6235{
6236	INIT_LIST_HEAD(&tr->func_probes);
6237	INIT_LIST_HEAD(&tr->mod_trace);
6238	INIT_LIST_HEAD(&tr->mod_notrace);
6239}
6240#else
6241
6242struct ftrace_ops global_ops = {
6243	.func			= ftrace_stub,
6244	.flags			= FTRACE_OPS_FL_RECURSION_SAFE |
6245				  FTRACE_OPS_FL_INITIALIZED |
6246				  FTRACE_OPS_FL_PID,
6247};
6248
6249static int __init ftrace_nodyn_init(void)
6250{
6251	ftrace_enabled = 1;
6252	return 0;
6253}
6254core_initcall(ftrace_nodyn_init);
6255
6256static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
6257static inline void ftrace_startup_enable(int command) { }
6258static inline void ftrace_startup_all(int command) { }
 
 
 
 
 
 
 
 
 
 
 
 
 
 
6259
6260# define ftrace_startup_sysctl()	do { } while (0)
6261# define ftrace_shutdown_sysctl()	do { } while (0)
6262
6263static void ftrace_update_trampoline(struct ftrace_ops *ops)
 
6264{
 
6265}
6266
6267#endif /* CONFIG_DYNAMIC_FTRACE */
6268
6269__init void ftrace_init_global_array_ops(struct trace_array *tr)
 
 
6270{
6271	tr->ops = &global_ops;
6272	tr->ops->private = tr;
6273	ftrace_init_trace_array(tr);
6274}
6275
6276void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
6277{
6278	/* If we filter on pids, update to use the pid function */
6279	if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
6280		if (WARN_ON(tr->ops->func != ftrace_stub))
6281			printk("ftrace ops had %pS for function\n",
6282			       tr->ops->func);
6283	}
6284	tr->ops->func = func;
6285	tr->ops->private = tr;
6286}
6287
6288void ftrace_reset_array_ops(struct trace_array *tr)
6289{
6290	tr->ops->func = ftrace_stub;
 
 
 
 
 
 
 
 
 
 
 
 
 
6291}
6292
6293static nokprobe_inline void
 
 
 
 
 
 
6294__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6295		       struct ftrace_ops *ignored, struct pt_regs *regs)
6296{
6297	struct ftrace_ops *op;
6298	int bit;
6299
 
 
 
6300	bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6301	if (bit < 0)
6302		return;
6303
6304	/*
6305	 * Some of the ops may be dynamically allocated,
6306	 * they must be freed after a synchronize_rcu().
6307	 */
6308	preempt_disable_notrace();
6309
6310	do_for_each_ftrace_op(op, ftrace_ops_list) {
6311		/* Stub functions don't need to be called nor tested */
6312		if (op->flags & FTRACE_OPS_FL_STUB)
6313			continue;
6314		/*
6315		 * Check the following for each ops before calling their func:
6316		 *  if RCU flag is set, then rcu_is_watching() must be true
6317		 *  if PER_CPU is set, then ftrace_function_local_disable()
6318		 *                          must be false
6319		 *  Otherwise test if the ip matches the ops filter
6320		 *
6321		 * If any of the above fails then the op->func() is not executed.
6322		 */
6323		if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
6324		    ftrace_ops_test(op, ip, regs)) {
6325			if (FTRACE_WARN_ON(!op->func)) {
6326				pr_warn("op=%p %pS\n", op, op);
6327				goto out;
6328			}
6329			op->func(ip, parent_ip, op, regs);
6330		}
6331	} while_for_each_ftrace_op(op);
6332out:
6333	preempt_enable_notrace();
6334	trace_clear_recursion(bit);
6335}
6336
6337/*
6338 * Some archs only support passing ip and parent_ip. Even though
6339 * the list function ignores the op parameter, we do not want any
6340 * C side effects, where a function is called without the caller
6341 * sending a third parameter.
6342 * Archs are to support both the regs and ftrace_ops at the same time.
6343 * If they support ftrace_ops, it is assumed they support regs.
6344 * If call backs want to use regs, they must either check for regs
6345 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
6346 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
6347 * An architecture can pass partial regs with ftrace_ops and still
6348 * set the ARCH_SUPPORTS_FTRACE_OPS.
6349 */
6350#if ARCH_SUPPORTS_FTRACE_OPS
6351static void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
6352				 struct ftrace_ops *op, struct pt_regs *regs)
6353{
6354	__ftrace_ops_list_func(ip, parent_ip, NULL, regs);
6355}
6356NOKPROBE_SYMBOL(ftrace_ops_list_func);
6357#else
6358static void ftrace_ops_no_ops(unsigned long ip, unsigned long parent_ip)
6359{
6360	__ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
6361}
6362NOKPROBE_SYMBOL(ftrace_ops_no_ops);
6363#endif
6364
6365/*
6366 * If there's only one function registered but it does not support
6367 * recursion, needs RCU protection and/or requires per cpu handling, then
6368 * this function will be called by the mcount trampoline.
6369 */
6370static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
6371				   struct ftrace_ops *op, struct pt_regs *regs)
6372{
6373	int bit;
6374
6375	if ((op->flags & FTRACE_OPS_FL_RCU) && !rcu_is_watching())
6376		return;
6377
6378	bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX);
6379	if (bit < 0)
6380		return;
6381
6382	preempt_disable_notrace();
6383
6384	op->func(ip, parent_ip, op, regs);
6385
6386	preempt_enable_notrace();
6387	trace_clear_recursion(bit);
 
 
 
 
6388}
6389NOKPROBE_SYMBOL(ftrace_ops_assist_func);
6390
6391/**
6392 * ftrace_ops_get_func - get the function a trampoline should call
6393 * @ops: the ops to get the function for
6394 *
6395 * Normally the mcount trampoline will call the ops->func, but there
6396 * are times that it should not. For example, if the ops does not
6397 * have its own recursion protection, then it should call the
6398 * ftrace_ops_assist_func() instead.
6399 *
6400 * Returns the function that the trampoline should call for @ops.
6401 */
6402ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
6403{
6404	/*
6405	 * If the function does not handle recursion, needs to be RCU safe,
6406	 * or does per cpu logic, then we need to call the assist handler.
6407	 */
6408	if (!(ops->flags & FTRACE_OPS_FL_RECURSION_SAFE) ||
6409	    ops->flags & FTRACE_OPS_FL_RCU)
6410		return ftrace_ops_assist_func;
6411
6412	return ops->func;
 
 
 
 
 
6413}
6414
6415static void
6416ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
6417		    struct task_struct *prev, struct task_struct *next)
6418{
6419	struct trace_array *tr = data;
6420	struct trace_pid_list *pid_list;
6421
6422	pid_list = rcu_dereference_sched(tr->function_pids);
 
 
 
 
6423
6424	this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6425		       trace_ignore_this_task(pid_list, next));
6426}
6427
6428static void
6429ftrace_pid_follow_sched_process_fork(void *data,
6430				     struct task_struct *self,
6431				     struct task_struct *task)
6432{
6433	struct trace_pid_list *pid_list;
6434	struct trace_array *tr = data;
6435
6436	pid_list = rcu_dereference_sched(tr->function_pids);
6437	trace_filter_add_remove_task(pid_list, self, task);
 
 
 
6438}
6439
6440static void
6441ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
6442{
6443	struct trace_pid_list *pid_list;
6444	struct trace_array *tr = data;
6445
6446	pid_list = rcu_dereference_sched(tr->function_pids);
6447	trace_filter_add_remove_task(pid_list, NULL, task);
6448}
6449
6450void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
6451{
6452	if (enable) {
6453		register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6454						  tr);
6455		register_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6456						  tr);
6457	} else {
6458		unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
6459						    tr);
6460		unregister_trace_sched_process_exit(ftrace_pid_follow_sched_process_exit,
6461						    tr);
6462	}
6463}
6464
6465static void clear_ftrace_pids(struct trace_array *tr)
6466{
6467	struct trace_pid_list *pid_list;
6468	int cpu;
 
6469
6470	pid_list = rcu_dereference_protected(tr->function_pids,
6471					     lockdep_is_held(&ftrace_lock));
6472	if (!pid_list)
6473		return;
6474
6475	unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
 
 
 
6476
6477	for_each_possible_cpu(cpu)
6478		per_cpu_ptr(tr->trace_buffer.data, cpu)->ftrace_ignore_pid = false;
6479
6480	rcu_assign_pointer(tr->function_pids, NULL);
6481
6482	/* Wait till all users are no longer using pid filtering */
6483	synchronize_rcu();
 
6484
6485	trace_free_pid_list(pid_list);
6486}
6487
6488void ftrace_clear_pids(struct trace_array *tr)
6489{
6490	mutex_lock(&ftrace_lock);
 
 
 
 
 
 
 
 
6491
6492	clear_ftrace_pids(tr);
 
6493
 
 
 
 
 
6494	mutex_unlock(&ftrace_lock);
 
6495}
6496
6497static void ftrace_pid_reset(struct trace_array *tr)
6498{
 
 
6499	mutex_lock(&ftrace_lock);
6500	clear_ftrace_pids(tr);
 
 
 
 
 
 
 
6501
6502	ftrace_update_pid_func();
6503	ftrace_startup_all(0);
6504
6505	mutex_unlock(&ftrace_lock);
6506}
6507
6508/* Greater than any max PID */
6509#define FTRACE_NO_PIDS		(void *)(PID_MAX_LIMIT + 1)
6510
6511static void *fpid_start(struct seq_file *m, loff_t *pos)
6512	__acquires(RCU)
6513{
6514	struct trace_pid_list *pid_list;
6515	struct trace_array *tr = m->private;
6516
6517	mutex_lock(&ftrace_lock);
6518	rcu_read_lock_sched();
6519
6520	pid_list = rcu_dereference_sched(tr->function_pids);
 
6521
6522	if (!pid_list)
6523		return !(*pos) ? FTRACE_NO_PIDS : NULL;
6524
6525	return trace_pid_start(pid_list, pos);
6526}
6527
6528static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
6529{
6530	struct trace_array *tr = m->private;
6531	struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
6532
6533	if (v == FTRACE_NO_PIDS)
6534		return NULL;
6535
6536	return trace_pid_next(pid_list, v, pos);
6537}
6538
6539static void fpid_stop(struct seq_file *m, void *p)
6540	__releases(RCU)
6541{
6542	rcu_read_unlock_sched();
6543	mutex_unlock(&ftrace_lock);
6544}
6545
6546static int fpid_show(struct seq_file *m, void *v)
6547{
6548	if (v == FTRACE_NO_PIDS) {
6549		seq_puts(m, "no pid\n");
 
 
6550		return 0;
6551	}
6552
6553	return trace_pid_show(m, v);
 
 
 
 
 
6554}
6555
6556static const struct seq_operations ftrace_pid_sops = {
6557	.start = fpid_start,
6558	.next = fpid_next,
6559	.stop = fpid_stop,
6560	.show = fpid_show,
6561};
6562
6563static int
6564ftrace_pid_open(struct inode *inode, struct file *file)
6565{
6566	struct trace_array *tr = inode->i_private;
6567	struct seq_file *m;
6568	int ret = 0;
6569
6570	ret = tracing_check_open_get_tr(tr);
6571	if (ret)
6572		return ret;
6573
6574	if ((file->f_mode & FMODE_WRITE) &&
6575	    (file->f_flags & O_TRUNC))
6576		ftrace_pid_reset(tr);
6577
6578	ret = seq_open(file, &ftrace_pid_sops);
6579	if (ret < 0) {
6580		trace_array_put(tr);
6581	} else {
6582		m = file->private_data;
6583		/* copy tr over to seq ops */
6584		m->private = tr;
6585	}
6586
6587	return ret;
6588}
6589
6590static void ignore_task_cpu(void *data)
6591{
6592	struct trace_array *tr = data;
6593	struct trace_pid_list *pid_list;
6594
6595	/*
6596	 * This function is called by on_each_cpu() while the
6597	 * event_mutex is held.
6598	 */
6599	pid_list = rcu_dereference_protected(tr->function_pids,
6600					     mutex_is_locked(&ftrace_lock));
6601
6602	this_cpu_write(tr->trace_buffer.data->ftrace_ignore_pid,
6603		       trace_ignore_this_task(pid_list, current));
6604}
6605
6606static ssize_t
6607ftrace_pid_write(struct file *filp, const char __user *ubuf,
6608		   size_t cnt, loff_t *ppos)
6609{
6610	struct seq_file *m = filp->private_data;
6611	struct trace_array *tr = m->private;
6612	struct trace_pid_list *filtered_pids = NULL;
6613	struct trace_pid_list *pid_list;
6614	ssize_t ret;
6615
6616	if (!cnt)
6617		return 0;
6618
6619	mutex_lock(&ftrace_lock);
6620
6621	filtered_pids = rcu_dereference_protected(tr->function_pids,
6622					     lockdep_is_held(&ftrace_lock));
6623
6624	ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
6625	if (ret < 0)
6626		goto out;
6627
6628	rcu_assign_pointer(tr->function_pids, pid_list);
 
6629
6630	if (filtered_pids) {
6631		synchronize_rcu();
6632		trace_free_pid_list(filtered_pids);
6633	} else if (pid_list) {
6634		/* Register a probe to set whether to ignore the tracing of a task */
6635		register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
6636	}
6637
6638	/*
6639	 * Ignoring of pids is done at task switch. But we have to
6640	 * check for those tasks that are currently running.
6641	 * Always do this in case a pid was appended or removed.
6642	 */
6643	on_each_cpu(ignore_task_cpu, tr, 1);
 
 
6644
6645	ftrace_update_pid_func();
6646	ftrace_startup_all(0);
6647 out:
6648	mutex_unlock(&ftrace_lock);
6649
6650	if (ret > 0)
6651		*ppos += ret;
6652
6653	return ret;
6654}
6655
6656static int
6657ftrace_pid_release(struct inode *inode, struct file *file)
6658{
6659	struct trace_array *tr = inode->i_private;
6660
6661	trace_array_put(tr);
6662
6663	return seq_release(inode, file);
6664}
6665
6666static const struct file_operations ftrace_pid_fops = {
6667	.open		= ftrace_pid_open,
6668	.write		= ftrace_pid_write,
6669	.read		= seq_read,
6670	.llseek		= tracing_lseek,
6671	.release	= ftrace_pid_release,
6672};
6673
6674void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
6675{
 
 
 
 
 
 
 
 
6676	trace_create_file("set_ftrace_pid", 0644, d_tracer,
6677			    tr, &ftrace_pid_fops);
6678}
6679
6680void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
6681					 struct dentry *d_tracer)
6682{
6683	/* Only the top level directory has the dyn_tracefs and profile */
6684	WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
6685
6686	ftrace_init_dyn_tracefs(d_tracer);
6687	ftrace_profile_tracefs(d_tracer);
6688}
 
6689
6690/**
6691 * ftrace_kill - kill ftrace
6692 *
6693 * This function should be used by panic code. It stops ftrace
6694 * but in a not so nice way. If you need to simply kill ftrace
6695 * from a non-atomic section, use ftrace_kill.
6696 */
6697void ftrace_kill(void)
6698{
6699	ftrace_disabled = 1;
6700	ftrace_enabled = 0;
6701	ftrace_trace_function = ftrace_stub;
6702}
6703
6704/**
6705 * Test if ftrace is dead or not.
6706 */
6707int ftrace_is_dead(void)
6708{
6709	return ftrace_disabled;
6710}
6711
6712/**
6713 * register_ftrace_function - register a function for profiling
6714 * @ops - ops structure that holds the function for profiling.
6715 *
6716 * Register a function to be called by all functions in the
6717 * kernel.
6718 *
6719 * Note: @ops->func and all the functions it calls must be labeled
6720 *       with "notrace", otherwise it will go into a
6721 *       recursive loop.
6722 */
6723int register_ftrace_function(struct ftrace_ops *ops)
6724{
6725	int ret = -1;
6726
6727	ftrace_ops_init(ops);
6728
6729	mutex_lock(&ftrace_lock);
6730
6731	ret = ftrace_startup(ops, 0);
6732
6733	mutex_unlock(&ftrace_lock);
6734
6735	return ret;
6736}
6737EXPORT_SYMBOL_GPL(register_ftrace_function);
6738
6739/**
6740 * unregister_ftrace_function - unregister a function for profiling.
6741 * @ops - ops structure that holds the function to unregister
6742 *
6743 * Unregister a function that was added to be called by ftrace profiling.
6744 */
6745int unregister_ftrace_function(struct ftrace_ops *ops)
6746{
6747	int ret;
6748
6749	mutex_lock(&ftrace_lock);
6750	ret = ftrace_shutdown(ops, 0);
6751	mutex_unlock(&ftrace_lock);
6752
6753	return ret;
6754}
6755EXPORT_SYMBOL_GPL(unregister_ftrace_function);
6756
6757int
6758ftrace_enable_sysctl(struct ctl_table *table, int write,
6759		     void __user *buffer, size_t *lenp,
6760		     loff_t *ppos)
6761{
6762	int ret = -ENODEV;
6763
6764	mutex_lock(&ftrace_lock);
6765
6766	if (unlikely(ftrace_disabled))
6767		goto out;
6768
6769	ret = proc_dointvec(table, write, buffer, lenp, ppos);
6770
6771	if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
6772		goto out;
6773
6774	last_ftrace_enabled = !!ftrace_enabled;
6775
6776	if (ftrace_enabled) {
6777
 
 
6778		/* we are starting ftrace again */
6779		if (rcu_dereference_protected(ftrace_ops_list,
6780			lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
6781			update_ftrace_function();
6782
6783		ftrace_startup_sysctl();
6784
6785	} else {
6786		/* stopping ftrace calls (just send to ftrace_stub) */
6787		ftrace_trace_function = ftrace_stub;
6788
6789		ftrace_shutdown_sysctl();
6790	}
6791
6792 out:
6793	mutex_unlock(&ftrace_lock);
6794	return ret;
6795}