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/* Flags that do not get reset */
  49#define FTRACE_NOCLEAR_FLAGS	(FTRACE_FL_DISABLED | FTRACE_FL_TOUCHED | \
  50				 FTRACE_FL_MODIFIED)
  51
  52#define FTRACE_INVALID_FUNCTION		"__ftrace_invalid_address__"
  53
  54#define FTRACE_WARN_ON(cond)			\
  55	({					\
  56		int ___r = cond;		\
  57		if (WARN_ON(___r))		\
  58			ftrace_kill();		\
  59		___r;				\
  60	})
  61
  62#define FTRACE_WARN_ON_ONCE(cond)		\
  63	({					\
  64		int ___r = cond;		\
  65		if (WARN_ON_ONCE(___r))		\
  66			ftrace_kill();		\
  67		___r;				\
  68	})
  69
  70/* hash bits for specific function selection */
  71#define FTRACE_HASH_DEFAULT_BITS 10
  72#define FTRACE_HASH_MAX_BITS 12
  73
  74#ifdef CONFIG_DYNAMIC_FTRACE
  75#define INIT_OPS_HASH(opsname)	\
  76	.func_hash		= &opsname.local_hash,			\
  77	.local_hash.regex_lock	= __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
  78#else
  79#define INIT_OPS_HASH(opsname)
  80#endif
  81
  82enum {
  83	FTRACE_MODIFY_ENABLE_FL		= (1 << 0),
  84	FTRACE_MODIFY_MAY_SLEEP_FL	= (1 << 1),
  85};
  86
  87struct ftrace_ops ftrace_list_end __read_mostly = {
  88	.func		= ftrace_stub,
  89	.flags		= FTRACE_OPS_FL_STUB,
  90	INIT_OPS_HASH(ftrace_list_end)
  91};
  92
  93/* ftrace_enabled is a method to turn ftrace on or off */
  94int ftrace_enabled __read_mostly;
  95static int __maybe_unused last_ftrace_enabled;
  96
  97/* Current function tracing op */
  98struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
  99/* What to set function_trace_op to */
 100static struct ftrace_ops *set_function_trace_op;
 101
 102static bool ftrace_pids_enabled(struct ftrace_ops *ops)
 103{
 104	struct trace_array *tr;
 105
 106	if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
 107		return false;
 108
 109	tr = ops->private;
 110
 111	return tr->function_pids != NULL || tr->function_no_pids != NULL;
 112}
 113
 114static void ftrace_update_trampoline(struct ftrace_ops *ops);
 115
 116/*
 117 * ftrace_disabled is set when an anomaly is discovered.
 118 * ftrace_disabled is much stronger than ftrace_enabled.
 119 */
 120static int ftrace_disabled __read_mostly;
 121
 122DEFINE_MUTEX(ftrace_lock);
 123
 124struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
 125ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
 126struct ftrace_ops global_ops;
 127
 128/* Defined by vmlinux.lds.h see the comment above arch_ftrace_ops_list_func for details */
 129void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
 130			  struct ftrace_ops *op, struct ftrace_regs *fregs);
 131
 132#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS
 133/*
 134 * Stub used to invoke the list ops without requiring a separate trampoline.
 135 */
 136const struct ftrace_ops ftrace_list_ops = {
 137	.func	= ftrace_ops_list_func,
 138	.flags	= FTRACE_OPS_FL_STUB,
 139};
 140
 141static void ftrace_ops_nop_func(unsigned long ip, unsigned long parent_ip,
 142				struct ftrace_ops *op,
 143				struct ftrace_regs *fregs)
 144{
 145	/* do nothing */
 146}
 147
 148/*
 149 * Stub used when a call site is disabled. May be called transiently by threads
 150 * which have made it into ftrace_caller but haven't yet recovered the ops at
 151 * the point the call site is disabled.
 152 */
 153const struct ftrace_ops ftrace_nop_ops = {
 154	.func	= ftrace_ops_nop_func,
 155	.flags  = FTRACE_OPS_FL_STUB,
 156};
 157#endif
 158
 159static inline void ftrace_ops_init(struct ftrace_ops *ops)
 160{
 161#ifdef CONFIG_DYNAMIC_FTRACE
 162	if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
 163		mutex_init(&ops->local_hash.regex_lock);
 164		ops->func_hash = &ops->local_hash;
 165		ops->flags |= FTRACE_OPS_FL_INITIALIZED;
 166	}
 167#endif
 168}
 169
 170static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
 171			    struct ftrace_ops *op, struct ftrace_regs *fregs)
 172{
 173	struct trace_array *tr = op->private;
 174	int pid;
 175
 176	if (tr) {
 177		pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
 178		if (pid == FTRACE_PID_IGNORE)
 179			return;
 180		if (pid != FTRACE_PID_TRACE &&
 181		    pid != current->pid)
 182			return;
 183	}
 184
 185	op->saved_func(ip, parent_ip, op, fregs);
 186}
 187
 188static void ftrace_sync_ipi(void *data)
 189{
 190	/* Probably not needed, but do it anyway */
 191	smp_rmb();
 192}
 193
 194static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
 195{
 196	/*
 197	 * If this is a dynamic or RCU ops, or we force list func,
 198	 * then it needs to call the list anyway.
 199	 */
 200	if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
 201	    FTRACE_FORCE_LIST_FUNC)
 202		return ftrace_ops_list_func;
 203
 204	return ftrace_ops_get_func(ops);
 205}
 206
 207static void update_ftrace_function(void)
 208{
 209	ftrace_func_t func;
 210
 211	/*
 212	 * Prepare the ftrace_ops that the arch callback will use.
 213	 * If there's only one ftrace_ops registered, the ftrace_ops_list
 214	 * will point to the ops we want.
 215	 */
 216	set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
 217						lockdep_is_held(&ftrace_lock));
 218
 219	/* If there's no ftrace_ops registered, just call the stub function */
 220	if (set_function_trace_op == &ftrace_list_end) {
 221		func = ftrace_stub;
 222
 223	/*
 224	 * If we are at the end of the list and this ops is
 225	 * recursion safe and not dynamic and the arch supports passing ops,
 226	 * then have the mcount trampoline call the function directly.
 227	 */
 228	} else if (rcu_dereference_protected(ftrace_ops_list->next,
 229			lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
 230		func = ftrace_ops_get_list_func(ftrace_ops_list);
 231
 232	} else {
 233		/* Just use the default ftrace_ops */
 234		set_function_trace_op = &ftrace_list_end;
 235		func = ftrace_ops_list_func;
 236	}
 237
 238	update_function_graph_func();
 239
 240	/* If there's no change, then do nothing more here */
 241	if (ftrace_trace_function == func)
 242		return;
 243
 244	/*
 245	 * If we are using the list function, it doesn't care
 246	 * about the function_trace_ops.
 247	 */
 248	if (func == ftrace_ops_list_func) {
 249		ftrace_trace_function = func;
 250		/*
 251		 * Don't even bother setting function_trace_ops,
 252		 * it would be racy to do so anyway.
 253		 */
 254		return;
 255	}
 256
 257#ifndef CONFIG_DYNAMIC_FTRACE
 258	/*
 259	 * For static tracing, we need to be a bit more careful.
 260	 * The function change takes affect immediately. Thus,
 261	 * we need to coordinate the setting of the function_trace_ops
 262	 * with the setting of the ftrace_trace_function.
 263	 *
 264	 * Set the function to the list ops, which will call the
 265	 * function we want, albeit indirectly, but it handles the
 266	 * ftrace_ops and doesn't depend on function_trace_op.
 267	 */
 268	ftrace_trace_function = ftrace_ops_list_func;
 269	/*
 270	 * Make sure all CPUs see this. Yes this is slow, but static
 271	 * tracing is slow and nasty to have enabled.
 272	 */
 273	synchronize_rcu_tasks_rude();
 274	/* Now all cpus are using the list ops. */
 275	function_trace_op = set_function_trace_op;
 276	/* Make sure the function_trace_op is visible on all CPUs */
 277	smp_wmb();
 278	/* Nasty way to force a rmb on all cpus */
 279	smp_call_function(ftrace_sync_ipi, NULL, 1);
 280	/* OK, we are all set to update the ftrace_trace_function now! */
 281#endif /* !CONFIG_DYNAMIC_FTRACE */
 282
 283	ftrace_trace_function = func;
 284}
 285
 286static void add_ftrace_ops(struct ftrace_ops __rcu **list,
 287			   struct ftrace_ops *ops)
 288{
 289	rcu_assign_pointer(ops->next, *list);
 290
 291	/*
 292	 * We are entering ops into the list but another
 293	 * CPU might be walking that list. We need to make sure
 294	 * the ops->next pointer is valid before another CPU sees
 295	 * the ops pointer included into the list.
 296	 */
 297	rcu_assign_pointer(*list, ops);
 298}
 299
 300static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
 301			     struct ftrace_ops *ops)
 302{
 303	struct ftrace_ops **p;
 304
 305	/*
 306	 * If we are removing the last function, then simply point
 307	 * to the ftrace_stub.
 308	 */
 309	if (rcu_dereference_protected(*list,
 310			lockdep_is_held(&ftrace_lock)) == ops &&
 311	    rcu_dereference_protected(ops->next,
 312			lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
 313		*list = &ftrace_list_end;
 314		return 0;
 315	}
 316
 317	for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
 318		if (*p == ops)
 319			break;
 320
 321	if (*p != ops)
 322		return -1;
 323
 324	*p = (*p)->next;
 325	return 0;
 326}
 327
 328static void ftrace_update_trampoline(struct ftrace_ops *ops);
 329
 330int __register_ftrace_function(struct ftrace_ops *ops)
 331{
 332	if (ops->flags & FTRACE_OPS_FL_DELETED)
 333		return -EINVAL;
 334
 335	if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
 336		return -EBUSY;
 337
 338#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 339	/*
 340	 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
 341	 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
 342	 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
 343	 */
 344	if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
 345	    !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
 346		return -EINVAL;
 347
 348	if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
 349		ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
 350#endif
 351	if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
 352		return -EBUSY;
 353
 354	if (!is_kernel_core_data((unsigned long)ops))
 355		ops->flags |= FTRACE_OPS_FL_DYNAMIC;
 356
 357	add_ftrace_ops(&ftrace_ops_list, ops);
 358
 359	/* Always save the function, and reset at unregistering */
 360	ops->saved_func = ops->func;
 361
 362	if (ftrace_pids_enabled(ops))
 363		ops->func = ftrace_pid_func;
 364
 365	ftrace_update_trampoline(ops);
 366
 367	if (ftrace_enabled)
 368		update_ftrace_function();
 369
 370	return 0;
 371}
 372
 373int __unregister_ftrace_function(struct ftrace_ops *ops)
 374{
 375	int ret;
 376
 377	if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
 378		return -EBUSY;
 379
 380	ret = remove_ftrace_ops(&ftrace_ops_list, ops);
 381
 382	if (ret < 0)
 383		return ret;
 384
 385	if (ftrace_enabled)
 386		update_ftrace_function();
 387
 388	ops->func = ops->saved_func;
 389
 390	return 0;
 391}
 392
 393static void ftrace_update_pid_func(void)
 394{
 395	struct ftrace_ops *op;
 396
 397	/* Only do something if we are tracing something */
 398	if (ftrace_trace_function == ftrace_stub)
 399		return;
 400
 401	do_for_each_ftrace_op(op, ftrace_ops_list) {
 402		if (op->flags & FTRACE_OPS_FL_PID) {
 403			op->func = ftrace_pids_enabled(op) ?
 404				ftrace_pid_func : op->saved_func;
 405			ftrace_update_trampoline(op);
 406		}
 407	} while_for_each_ftrace_op(op);
 408
 409	update_ftrace_function();
 410}
 411
 412#ifdef CONFIG_FUNCTION_PROFILER
 413struct ftrace_profile {
 414	struct hlist_node		node;
 415	unsigned long			ip;
 416	unsigned long			counter;
 417#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 418	unsigned long long		time;
 419	unsigned long long		time_squared;
 420#endif
 421};
 422
 423struct ftrace_profile_page {
 424	struct ftrace_profile_page	*next;
 425	unsigned long			index;
 426	struct ftrace_profile		records[];
 427};
 428
 429struct ftrace_profile_stat {
 430	atomic_t			disabled;
 431	struct hlist_head		*hash;
 432	struct ftrace_profile_page	*pages;
 433	struct ftrace_profile_page	*start;
 434	struct tracer_stat		stat;
 435};
 436
 437#define PROFILE_RECORDS_SIZE						\
 438	(PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
 439
 440#define PROFILES_PER_PAGE					\
 441	(PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
 442
 443static int ftrace_profile_enabled __read_mostly;
 444
 445/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
 446static DEFINE_MUTEX(ftrace_profile_lock);
 447
 448static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
 449
 450#define FTRACE_PROFILE_HASH_BITS 10
 451#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
 452
 453static void *
 454function_stat_next(void *v, int idx)
 455{
 456	struct ftrace_profile *rec = v;
 457	struct ftrace_profile_page *pg;
 458
 459	pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
 460
 461 again:
 462	if (idx != 0)
 463		rec++;
 464
 465	if ((void *)rec >= (void *)&pg->records[pg->index]) {
 466		pg = pg->next;
 467		if (!pg)
 468			return NULL;
 469		rec = &pg->records[0];
 470		if (!rec->counter)
 471			goto again;
 472	}
 473
 474	return rec;
 475}
 476
 477static void *function_stat_start(struct tracer_stat *trace)
 478{
 479	struct ftrace_profile_stat *stat =
 480		container_of(trace, struct ftrace_profile_stat, stat);
 481
 482	if (!stat || !stat->start)
 483		return NULL;
 484
 485	return function_stat_next(&stat->start->records[0], 0);
 486}
 487
 488#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 489/* function graph compares on total time */
 490static int function_stat_cmp(const void *p1, const void *p2)
 491{
 492	const struct ftrace_profile *a = p1;
 493	const struct ftrace_profile *b = p2;
 494
 495	if (a->time < b->time)
 496		return -1;
 497	if (a->time > b->time)
 498		return 1;
 499	else
 500		return 0;
 501}
 502#else
 503/* not function graph compares against hits */
 504static int function_stat_cmp(const void *p1, const void *p2)
 505{
 506	const struct ftrace_profile *a = p1;
 507	const struct ftrace_profile *b = p2;
 508
 509	if (a->counter < b->counter)
 510		return -1;
 511	if (a->counter > b->counter)
 512		return 1;
 513	else
 514		return 0;
 515}
 516#endif
 517
 518static int function_stat_headers(struct seq_file *m)
 519{
 520#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 521	seq_puts(m, "  Function                               "
 522		 "Hit    Time            Avg             s^2\n"
 523		    "  --------                               "
 524		 "---    ----            ---             ---\n");
 525#else
 526	seq_puts(m, "  Function                               Hit\n"
 527		    "  --------                               ---\n");
 528#endif
 529	return 0;
 530}
 531
 532static int function_stat_show(struct seq_file *m, void *v)
 533{
 534	struct ftrace_profile *rec = v;
 535	char str[KSYM_SYMBOL_LEN];
 536	int ret = 0;
 537#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 538	static struct trace_seq s;
 539	unsigned long long avg;
 540	unsigned long long stddev;
 541#endif
 542	mutex_lock(&ftrace_profile_lock);
 543
 544	/* we raced with function_profile_reset() */
 545	if (unlikely(rec->counter == 0)) {
 546		ret = -EBUSY;
 547		goto out;
 548	}
 549
 550#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 551	avg = div64_ul(rec->time, rec->counter);
 552	if (tracing_thresh && (avg < tracing_thresh))
 553		goto out;
 554#endif
 555
 556	kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 557	seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
 558
 559#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 560	seq_puts(m, "    ");
 561
 562	/* Sample standard deviation (s^2) */
 563	if (rec->counter <= 1)
 564		stddev = 0;
 565	else {
 566		/*
 567		 * Apply Welford's method:
 568		 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
 569		 */
 570		stddev = rec->counter * rec->time_squared -
 571			 rec->time * rec->time;
 572
 573		/*
 574		 * Divide only 1000 for ns^2 -> us^2 conversion.
 575		 * trace_print_graph_duration will divide 1000 again.
 576		 */
 577		stddev = div64_ul(stddev,
 578				  rec->counter * (rec->counter - 1) * 1000);
 579	}
 580
 581	trace_seq_init(&s);
 582	trace_print_graph_duration(rec->time, &s);
 583	trace_seq_puts(&s, "    ");
 584	trace_print_graph_duration(avg, &s);
 585	trace_seq_puts(&s, "    ");
 586	trace_print_graph_duration(stddev, &s);
 587	trace_print_seq(m, &s);
 588#endif
 589	seq_putc(m, '\n');
 590out:
 591	mutex_unlock(&ftrace_profile_lock);
 592
 593	return ret;
 594}
 595
 596static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
 597{
 598	struct ftrace_profile_page *pg;
 599
 600	pg = stat->pages = stat->start;
 601
 602	while (pg) {
 603		memset(pg->records, 0, PROFILE_RECORDS_SIZE);
 604		pg->index = 0;
 605		pg = pg->next;
 606	}
 607
 608	memset(stat->hash, 0,
 609	       FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
 610}
 611
 612static int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
 613{
 614	struct ftrace_profile_page *pg;
 615	int functions;
 616	int pages;
 617	int i;
 618
 619	/* If we already allocated, do nothing */
 620	if (stat->pages)
 621		return 0;
 622
 623	stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
 624	if (!stat->pages)
 625		return -ENOMEM;
 626
 627#ifdef CONFIG_DYNAMIC_FTRACE
 628	functions = ftrace_update_tot_cnt;
 629#else
 630	/*
 631	 * We do not know the number of functions that exist because
 632	 * dynamic tracing is what counts them. With past experience
 633	 * we have around 20K functions. That should be more than enough.
 634	 * It is highly unlikely we will execute every function in
 635	 * the kernel.
 636	 */
 637	functions = 20000;
 638#endif
 639
 640	pg = stat->start = stat->pages;
 641
 642	pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
 643
 644	for (i = 1; i < pages; i++) {
 645		pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 646		if (!pg->next)
 647			goto out_free;
 648		pg = pg->next;
 649	}
 650
 651	return 0;
 652
 653 out_free:
 654	pg = stat->start;
 655	while (pg) {
 656		unsigned long tmp = (unsigned long)pg;
 657
 658		pg = pg->next;
 659		free_page(tmp);
 660	}
 661
 662	stat->pages = NULL;
 663	stat->start = NULL;
 664
 665	return -ENOMEM;
 666}
 667
 668static int ftrace_profile_init_cpu(int cpu)
 669{
 670	struct ftrace_profile_stat *stat;
 671	int size;
 672
 673	stat = &per_cpu(ftrace_profile_stats, cpu);
 674
 675	if (stat->hash) {
 676		/* If the profile is already created, simply reset it */
 677		ftrace_profile_reset(stat);
 678		return 0;
 679	}
 680
 681	/*
 682	 * We are profiling all functions, but usually only a few thousand
 683	 * functions are hit. We'll make a hash of 1024 items.
 684	 */
 685	size = FTRACE_PROFILE_HASH_SIZE;
 686
 687	stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
 688
 689	if (!stat->hash)
 690		return -ENOMEM;
 691
 692	/* Preallocate the function profiling pages */
 693	if (ftrace_profile_pages_init(stat) < 0) {
 694		kfree(stat->hash);
 695		stat->hash = NULL;
 696		return -ENOMEM;
 697	}
 698
 699	return 0;
 700}
 701
 702static int ftrace_profile_init(void)
 703{
 704	int cpu;
 705	int ret = 0;
 706
 707	for_each_possible_cpu(cpu) {
 708		ret = ftrace_profile_init_cpu(cpu);
 709		if (ret)
 710			break;
 711	}
 712
 713	return ret;
 714}
 715
 716/* interrupts must be disabled */
 717static struct ftrace_profile *
 718ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
 719{
 720	struct ftrace_profile *rec;
 721	struct hlist_head *hhd;
 722	unsigned long key;
 723
 724	key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
 725	hhd = &stat->hash[key];
 726
 727	if (hlist_empty(hhd))
 728		return NULL;
 729
 730	hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
 731		if (rec->ip == ip)
 732			return rec;
 733	}
 734
 735	return NULL;
 736}
 737
 738static void ftrace_add_profile(struct ftrace_profile_stat *stat,
 739			       struct ftrace_profile *rec)
 740{
 741	unsigned long key;
 742
 743	key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
 744	hlist_add_head_rcu(&rec->node, &stat->hash[key]);
 745}
 746
 747/*
 748 * The memory is already allocated, this simply finds a new record to use.
 749 */
 750static struct ftrace_profile *
 751ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
 752{
 753	struct ftrace_profile *rec = NULL;
 754
 755	/* prevent recursion (from NMIs) */
 756	if (atomic_inc_return(&stat->disabled) != 1)
 757		goto out;
 758
 759	/*
 760	 * Try to find the function again since an NMI
 761	 * could have added it
 762	 */
 763	rec = ftrace_find_profiled_func(stat, ip);
 764	if (rec)
 765		goto out;
 766
 767	if (stat->pages->index == PROFILES_PER_PAGE) {
 768		if (!stat->pages->next)
 769			goto out;
 770		stat->pages = stat->pages->next;
 771	}
 772
 773	rec = &stat->pages->records[stat->pages->index++];
 774	rec->ip = ip;
 775	ftrace_add_profile(stat, rec);
 776
 777 out:
 778	atomic_dec(&stat->disabled);
 779
 780	return rec;
 781}
 782
 783static void
 784function_profile_call(unsigned long ip, unsigned long parent_ip,
 785		      struct ftrace_ops *ops, struct ftrace_regs *fregs)
 786{
 787	struct ftrace_profile_stat *stat;
 788	struct ftrace_profile *rec;
 789	unsigned long flags;
 790
 791	if (!ftrace_profile_enabled)
 792		return;
 793
 794	local_irq_save(flags);
 795
 796	stat = this_cpu_ptr(&ftrace_profile_stats);
 797	if (!stat->hash || !ftrace_profile_enabled)
 798		goto out;
 799
 800	rec = ftrace_find_profiled_func(stat, ip);
 801	if (!rec) {
 802		rec = ftrace_profile_alloc(stat, ip);
 803		if (!rec)
 804			goto out;
 805	}
 806
 807	rec->counter++;
 808 out:
 809	local_irq_restore(flags);
 810}
 811
 812#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 813static bool fgraph_graph_time = true;
 814
 815void ftrace_graph_graph_time_control(bool enable)
 816{
 817	fgraph_graph_time = enable;
 818}
 819
 820static int profile_graph_entry(struct ftrace_graph_ent *trace)
 821{
 822	struct ftrace_ret_stack *ret_stack;
 823
 824	function_profile_call(trace->func, 0, NULL, NULL);
 825
 826	/* If function graph is shutting down, ret_stack can be NULL */
 827	if (!current->ret_stack)
 828		return 0;
 829
 830	ret_stack = ftrace_graph_get_ret_stack(current, 0);
 831	if (ret_stack)
 832		ret_stack->subtime = 0;
 833
 834	return 1;
 835}
 836
 837static void profile_graph_return(struct ftrace_graph_ret *trace)
 838{
 839	struct ftrace_ret_stack *ret_stack;
 840	struct ftrace_profile_stat *stat;
 841	unsigned long long calltime;
 842	struct ftrace_profile *rec;
 843	unsigned long flags;
 844
 845	local_irq_save(flags);
 846	stat = this_cpu_ptr(&ftrace_profile_stats);
 847	if (!stat->hash || !ftrace_profile_enabled)
 848		goto out;
 849
 850	/* If the calltime was zero'd ignore it */
 851	if (!trace->calltime)
 852		goto out;
 853
 854	calltime = trace->rettime - trace->calltime;
 855
 856	if (!fgraph_graph_time) {
 857
 858		/* Append this call time to the parent time to subtract */
 859		ret_stack = ftrace_graph_get_ret_stack(current, 1);
 860		if (ret_stack)
 861			ret_stack->subtime += calltime;
 862
 863		ret_stack = ftrace_graph_get_ret_stack(current, 0);
 864		if (ret_stack && ret_stack->subtime < calltime)
 865			calltime -= ret_stack->subtime;
 866		else
 867			calltime = 0;
 868	}
 869
 870	rec = ftrace_find_profiled_func(stat, trace->func);
 871	if (rec) {
 872		rec->time += calltime;
 873		rec->time_squared += calltime * calltime;
 874	}
 875
 876 out:
 877	local_irq_restore(flags);
 878}
 879
 880static struct fgraph_ops fprofiler_ops = {
 881	.entryfunc = &profile_graph_entry,
 882	.retfunc = &profile_graph_return,
 883};
 884
 885static int register_ftrace_profiler(void)
 886{
 887	return register_ftrace_graph(&fprofiler_ops);
 888}
 889
 890static void unregister_ftrace_profiler(void)
 891{
 892	unregister_ftrace_graph(&fprofiler_ops);
 893}
 894#else
 895static struct ftrace_ops ftrace_profile_ops __read_mostly = {
 896	.func		= function_profile_call,
 897	.flags		= FTRACE_OPS_FL_INITIALIZED,
 898	INIT_OPS_HASH(ftrace_profile_ops)
 899};
 900
 901static int register_ftrace_profiler(void)
 902{
 903	return register_ftrace_function(&ftrace_profile_ops);
 904}
 905
 906static void unregister_ftrace_profiler(void)
 907{
 908	unregister_ftrace_function(&ftrace_profile_ops);
 909}
 910#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 911
 912static ssize_t
 913ftrace_profile_write(struct file *filp, const char __user *ubuf,
 914		     size_t cnt, loff_t *ppos)
 915{
 916	unsigned long val;
 917	int ret;
 918
 919	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
 920	if (ret)
 921		return ret;
 922
 923	val = !!val;
 924
 925	mutex_lock(&ftrace_profile_lock);
 926	if (ftrace_profile_enabled ^ val) {
 927		if (val) {
 928			ret = ftrace_profile_init();
 929			if (ret < 0) {
 930				cnt = ret;
 931				goto out;
 932			}
 933
 934			ret = register_ftrace_profiler();
 935			if (ret < 0) {
 936				cnt = ret;
 937				goto out;
 938			}
 939			ftrace_profile_enabled = 1;
 940		} else {
 941			ftrace_profile_enabled = 0;
 942			/*
 943			 * unregister_ftrace_profiler calls stop_machine
 944			 * so this acts like an synchronize_rcu.
 945			 */
 946			unregister_ftrace_profiler();
 947		}
 948	}
 949 out:
 950	mutex_unlock(&ftrace_profile_lock);
 951
 952	*ppos += cnt;
 953
 954	return cnt;
 955}
 956
 957static ssize_t
 958ftrace_profile_read(struct file *filp, char __user *ubuf,
 959		     size_t cnt, loff_t *ppos)
 960{
 961	char buf[64];		/* big enough to hold a number */
 962	int r;
 963
 964	r = sprintf(buf, "%u\n", ftrace_profile_enabled);
 965	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 966}
 967
 968static const struct file_operations ftrace_profile_fops = {
 969	.open		= tracing_open_generic,
 970	.read		= ftrace_profile_read,
 971	.write		= ftrace_profile_write,
 972	.llseek		= default_llseek,
 973};
 974
 975/* used to initialize the real stat files */
 976static struct tracer_stat function_stats __initdata = {
 977	.name		= "functions",
 978	.stat_start	= function_stat_start,
 979	.stat_next	= function_stat_next,
 980	.stat_cmp	= function_stat_cmp,
 981	.stat_headers	= function_stat_headers,
 982	.stat_show	= function_stat_show
 983};
 984
 985static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
 986{
 987	struct ftrace_profile_stat *stat;
 988	char *name;
 989	int ret;
 990	int cpu;
 991
 992	for_each_possible_cpu(cpu) {
 993		stat = &per_cpu(ftrace_profile_stats, cpu);
 994
 995		name = kasprintf(GFP_KERNEL, "function%d", cpu);
 996		if (!name) {
 997			/*
 998			 * The files created are permanent, if something happens
 999			 * we still do not free memory.
1000			 */
1001			WARN(1,
1002			     "Could not allocate stat file for cpu %d\n",
1003			     cpu);
1004			return;
1005		}
1006		stat->stat = function_stats;
1007		stat->stat.name = name;
1008		ret = register_stat_tracer(&stat->stat);
1009		if (ret) {
1010			WARN(1,
1011			     "Could not register function stat for cpu %d\n",
1012			     cpu);
1013			kfree(name);
1014			return;
1015		}
1016	}
1017
1018	trace_create_file("function_profile_enabled",
1019			  TRACE_MODE_WRITE, d_tracer, NULL,
1020			  &ftrace_profile_fops);
1021}
1022
1023#else /* CONFIG_FUNCTION_PROFILER */
1024static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
1025{
1026}
1027#endif /* CONFIG_FUNCTION_PROFILER */
1028
1029#ifdef CONFIG_DYNAMIC_FTRACE
1030
1031static struct ftrace_ops *removed_ops;
1032
1033/*
1034 * Set when doing a global update, like enabling all recs or disabling them.
1035 * It is not set when just updating a single ftrace_ops.
1036 */
1037static bool update_all_ops;
1038
1039#ifndef CONFIG_FTRACE_MCOUNT_RECORD
1040# error Dynamic ftrace depends on MCOUNT_RECORD
1041#endif
1042
1043struct ftrace_func_probe {
1044	struct ftrace_probe_ops	*probe_ops;
1045	struct ftrace_ops	ops;
1046	struct trace_array	*tr;
1047	struct list_head	list;
1048	void			*data;
1049	int			ref;
1050};
1051
1052/*
1053 * We make these constant because no one should touch them,
1054 * but they are used as the default "empty hash", to avoid allocating
1055 * it all the time. These are in a read only section such that if
1056 * anyone does try to modify it, it will cause an exception.
1057 */
1058static const struct hlist_head empty_buckets[1];
1059static const struct ftrace_hash empty_hash = {
1060	.buckets = (struct hlist_head *)empty_buckets,
1061};
1062#define EMPTY_HASH	((struct ftrace_hash *)&empty_hash)
1063
1064struct ftrace_ops global_ops = {
1065	.func				= ftrace_stub,
1066	.local_hash.notrace_hash	= EMPTY_HASH,
1067	.local_hash.filter_hash		= EMPTY_HASH,
1068	INIT_OPS_HASH(global_ops)
1069	.flags				= FTRACE_OPS_FL_INITIALIZED |
1070					  FTRACE_OPS_FL_PID,
1071};
1072
1073/*
1074 * Used by the stack unwinder to know about dynamic ftrace trampolines.
1075 */
1076struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1077{
1078	struct ftrace_ops *op = NULL;
1079
1080	/*
1081	 * Some of the ops may be dynamically allocated,
1082	 * they are freed after a synchronize_rcu().
1083	 */
1084	preempt_disable_notrace();
1085
1086	do_for_each_ftrace_op(op, ftrace_ops_list) {
1087		/*
1088		 * This is to check for dynamically allocated trampolines.
1089		 * Trampolines that are in kernel text will have
1090		 * core_kernel_text() return true.
1091		 */
1092		if (op->trampoline && op->trampoline_size)
1093			if (addr >= op->trampoline &&
1094			    addr < op->trampoline + op->trampoline_size) {
1095				preempt_enable_notrace();
1096				return op;
1097			}
1098	} while_for_each_ftrace_op(op);
1099	preempt_enable_notrace();
1100
1101	return NULL;
1102}
1103
1104/*
1105 * This is used by __kernel_text_address() to return true if the
1106 * address is on a dynamically allocated trampoline that would
1107 * not return true for either core_kernel_text() or
1108 * is_module_text_address().
1109 */
1110bool is_ftrace_trampoline(unsigned long addr)
1111{
1112	return ftrace_ops_trampoline(addr) != NULL;
1113}
1114
1115struct ftrace_page {
1116	struct ftrace_page	*next;
1117	struct dyn_ftrace	*records;
1118	int			index;
1119	int			order;
1120};
1121
1122#define ENTRY_SIZE sizeof(struct dyn_ftrace)
1123#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1124
1125static struct ftrace_page	*ftrace_pages_start;
1126static struct ftrace_page	*ftrace_pages;
1127
1128static __always_inline unsigned long
1129ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1130{
1131	if (hash->size_bits > 0)
1132		return hash_long(ip, hash->size_bits);
1133
1134	return 0;
1135}
1136
1137/* Only use this function if ftrace_hash_empty() has already been tested */
1138static __always_inline struct ftrace_func_entry *
1139__ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1140{
1141	unsigned long key;
1142	struct ftrace_func_entry *entry;
1143	struct hlist_head *hhd;
1144
1145	key = ftrace_hash_key(hash, ip);
1146	hhd = &hash->buckets[key];
1147
1148	hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1149		if (entry->ip == ip)
1150			return entry;
1151	}
1152	return NULL;
1153}
1154
1155/**
1156 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1157 * @hash: The hash to look at
1158 * @ip: The instruction pointer to test
1159 *
1160 * Search a given @hash to see if a given instruction pointer (@ip)
1161 * exists in it.
1162 *
1163 * Returns the entry that holds the @ip if found. NULL otherwise.
1164 */
1165struct ftrace_func_entry *
1166ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1167{
1168	if (ftrace_hash_empty(hash))
1169		return NULL;
1170
1171	return __ftrace_lookup_ip(hash, ip);
1172}
1173
1174static void __add_hash_entry(struct ftrace_hash *hash,
1175			     struct ftrace_func_entry *entry)
1176{
1177	struct hlist_head *hhd;
1178	unsigned long key;
1179
1180	key = ftrace_hash_key(hash, entry->ip);
1181	hhd = &hash->buckets[key];
1182	hlist_add_head(&entry->hlist, hhd);
1183	hash->count++;
1184}
1185
1186static struct ftrace_func_entry *
1187add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1188{
1189	struct ftrace_func_entry *entry;
1190
1191	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1192	if (!entry)
1193		return NULL;
1194
1195	entry->ip = ip;
1196	__add_hash_entry(hash, entry);
1197
1198	return entry;
1199}
1200
1201static void
1202free_hash_entry(struct ftrace_hash *hash,
1203		  struct ftrace_func_entry *entry)
1204{
1205	hlist_del(&entry->hlist);
1206	kfree(entry);
1207	hash->count--;
1208}
1209
1210static void
1211remove_hash_entry(struct ftrace_hash *hash,
1212		  struct ftrace_func_entry *entry)
1213{
1214	hlist_del_rcu(&entry->hlist);
1215	hash->count--;
1216}
1217
1218static void ftrace_hash_clear(struct ftrace_hash *hash)
1219{
1220	struct hlist_head *hhd;
1221	struct hlist_node *tn;
1222	struct ftrace_func_entry *entry;
1223	int size = 1 << hash->size_bits;
1224	int i;
1225
1226	if (!hash->count)
1227		return;
1228
1229	for (i = 0; i < size; i++) {
1230		hhd = &hash->buckets[i];
1231		hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1232			free_hash_entry(hash, entry);
1233	}
1234	FTRACE_WARN_ON(hash->count);
1235}
1236
1237static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1238{
1239	list_del(&ftrace_mod->list);
1240	kfree(ftrace_mod->module);
1241	kfree(ftrace_mod->func);
1242	kfree(ftrace_mod);
1243}
1244
1245static void clear_ftrace_mod_list(struct list_head *head)
1246{
1247	struct ftrace_mod_load *p, *n;
1248
1249	/* stack tracer isn't supported yet */
1250	if (!head)
1251		return;
1252
1253	mutex_lock(&ftrace_lock);
1254	list_for_each_entry_safe(p, n, head, list)
1255		free_ftrace_mod(p);
1256	mutex_unlock(&ftrace_lock);
1257}
1258
1259static void free_ftrace_hash(struct ftrace_hash *hash)
1260{
1261	if (!hash || hash == EMPTY_HASH)
1262		return;
1263	ftrace_hash_clear(hash);
1264	kfree(hash->buckets);
1265	kfree(hash);
1266}
1267
1268static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1269{
1270	struct ftrace_hash *hash;
1271
1272	hash = container_of(rcu, struct ftrace_hash, rcu);
1273	free_ftrace_hash(hash);
1274}
1275
1276static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1277{
1278	if (!hash || hash == EMPTY_HASH)
1279		return;
1280	call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1281}
1282
1283/**
1284 * ftrace_free_filter - remove all filters for an ftrace_ops
1285 * @ops - the ops to remove the filters from
1286 */
1287void ftrace_free_filter(struct ftrace_ops *ops)
1288{
1289	ftrace_ops_init(ops);
1290	free_ftrace_hash(ops->func_hash->filter_hash);
1291	free_ftrace_hash(ops->func_hash->notrace_hash);
1292}
1293EXPORT_SYMBOL_GPL(ftrace_free_filter);
1294
1295static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1296{
1297	struct ftrace_hash *hash;
1298	int size;
1299
1300	hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1301	if (!hash)
1302		return NULL;
1303
1304	size = 1 << size_bits;
1305	hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1306
1307	if (!hash->buckets) {
1308		kfree(hash);
1309		return NULL;
1310	}
1311
1312	hash->size_bits = size_bits;
1313
1314	return hash;
1315}
1316
1317
1318static int ftrace_add_mod(struct trace_array *tr,
1319			  const char *func, const char *module,
1320			  int enable)
1321{
1322	struct ftrace_mod_load *ftrace_mod;
1323	struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1324
1325	ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1326	if (!ftrace_mod)
1327		return -ENOMEM;
1328
1329	INIT_LIST_HEAD(&ftrace_mod->list);
1330	ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1331	ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1332	ftrace_mod->enable = enable;
1333
1334	if (!ftrace_mod->func || !ftrace_mod->module)
1335		goto out_free;
1336
1337	list_add(&ftrace_mod->list, mod_head);
1338
1339	return 0;
1340
1341 out_free:
1342	free_ftrace_mod(ftrace_mod);
1343
1344	return -ENOMEM;
1345}
1346
1347static struct ftrace_hash *
1348alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1349{
1350	struct ftrace_func_entry *entry;
1351	struct ftrace_hash *new_hash;
1352	int size;
 
1353	int i;
1354
1355	new_hash = alloc_ftrace_hash(size_bits);
1356	if (!new_hash)
1357		return NULL;
1358
1359	if (hash)
1360		new_hash->flags = hash->flags;
1361
1362	/* Empty hash? */
1363	if (ftrace_hash_empty(hash))
1364		return new_hash;
1365
1366	size = 1 << hash->size_bits;
1367	for (i = 0; i < size; i++) {
1368		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1369			if (add_hash_entry(new_hash, entry->ip) == NULL)
 
1370				goto free_hash;
1371		}
1372	}
1373
1374	FTRACE_WARN_ON(new_hash->count != hash->count);
1375
1376	return new_hash;
1377
1378 free_hash:
1379	free_ftrace_hash(new_hash);
1380	return NULL;
1381}
1382
1383static void
1384ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1385static void
1386ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1387
1388static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1389				       struct ftrace_hash *new_hash);
1390
1391static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
1392{
1393	struct ftrace_func_entry *entry;
1394	struct ftrace_hash *new_hash;
1395	struct hlist_head *hhd;
1396	struct hlist_node *tn;
1397	int bits = 0;
1398	int i;
1399
1400	/*
1401	 * Use around half the size (max bit of it), but
1402	 * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
1403	 */
1404	bits = fls(size / 2);
1405
1406	/* Don't allocate too much */
1407	if (bits > FTRACE_HASH_MAX_BITS)
1408		bits = FTRACE_HASH_MAX_BITS;
1409
1410	new_hash = alloc_ftrace_hash(bits);
1411	if (!new_hash)
1412		return NULL;
1413
1414	new_hash->flags = src->flags;
1415
1416	size = 1 << src->size_bits;
1417	for (i = 0; i < size; i++) {
1418		hhd = &src->buckets[i];
1419		hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1420			remove_hash_entry(src, entry);
1421			__add_hash_entry(new_hash, entry);
1422		}
1423	}
1424	return new_hash;
1425}
1426
1427static struct ftrace_hash *
1428__ftrace_hash_move(struct ftrace_hash *src)
1429{
1430	int size = src->count;
1431
1432	/*
1433	 * If the new source is empty, just return the empty_hash.
1434	 */
1435	if (ftrace_hash_empty(src))
1436		return EMPTY_HASH;
1437
1438	return dup_hash(src, size);
1439}
1440
1441static int
1442ftrace_hash_move(struct ftrace_ops *ops, int enable,
1443		 struct ftrace_hash **dst, struct ftrace_hash *src)
1444{
1445	struct ftrace_hash *new_hash;
1446	int ret;
1447
1448	/* Reject setting notrace hash on IPMODIFY ftrace_ops */
1449	if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1450		return -EINVAL;
1451
1452	new_hash = __ftrace_hash_move(src);
1453	if (!new_hash)
1454		return -ENOMEM;
1455
1456	/* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1457	if (enable) {
1458		/* IPMODIFY should be updated only when filter_hash updating */
1459		ret = ftrace_hash_ipmodify_update(ops, new_hash);
1460		if (ret < 0) {
1461			free_ftrace_hash(new_hash);
1462			return ret;
1463		}
1464	}
1465
1466	/*
1467	 * Remove the current set, update the hash and add
1468	 * them back.
1469	 */
1470	ftrace_hash_rec_disable_modify(ops, enable);
1471
1472	rcu_assign_pointer(*dst, new_hash);
1473
1474	ftrace_hash_rec_enable_modify(ops, enable);
1475
1476	return 0;
1477}
1478
1479static bool hash_contains_ip(unsigned long ip,
1480			     struct ftrace_ops_hash *hash)
1481{
1482	/*
1483	 * The function record is a match if it exists in the filter
1484	 * hash and not in the notrace hash. Note, an empty hash is
1485	 * considered a match for the filter hash, but an empty
1486	 * notrace hash is considered not in the notrace hash.
1487	 */
1488	return (ftrace_hash_empty(hash->filter_hash) ||
1489		__ftrace_lookup_ip(hash->filter_hash, ip)) &&
1490		(ftrace_hash_empty(hash->notrace_hash) ||
1491		 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1492}
1493
1494/*
1495 * Test the hashes for this ops to see if we want to call
1496 * the ops->func or not.
1497 *
1498 * It's a match if the ip is in the ops->filter_hash or
1499 * the filter_hash does not exist or is empty,
1500 *  AND
1501 * the ip is not in the ops->notrace_hash.
1502 *
1503 * This needs to be called with preemption disabled as
1504 * the hashes are freed with call_rcu().
1505 */
1506int
1507ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1508{
1509	struct ftrace_ops_hash hash;
1510	int ret;
1511
1512#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1513	/*
1514	 * There's a small race when adding ops that the ftrace handler
1515	 * that wants regs, may be called without them. We can not
1516	 * allow that handler to be called if regs is NULL.
1517	 */
1518	if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1519		return 0;
1520#endif
1521
1522	rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1523	rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1524
1525	if (hash_contains_ip(ip, &hash))
1526		ret = 1;
1527	else
1528		ret = 0;
1529
1530	return ret;
1531}
1532
1533/*
1534 * This is a double for. Do not use 'break' to break out of the loop,
1535 * you must use a goto.
1536 */
1537#define do_for_each_ftrace_rec(pg, rec)					\
1538	for (pg = ftrace_pages_start; pg; pg = pg->next) {		\
1539		int _____i;						\
1540		for (_____i = 0; _____i < pg->index; _____i++) {	\
1541			rec = &pg->records[_____i];
1542
1543#define while_for_each_ftrace_rec()		\
1544		}				\
1545	}
1546
1547
1548static int ftrace_cmp_recs(const void *a, const void *b)
1549{
1550	const struct dyn_ftrace *key = a;
1551	const struct dyn_ftrace *rec = b;
1552
1553	if (key->flags < rec->ip)
1554		return -1;
1555	if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1556		return 1;
1557	return 0;
1558}
1559
1560static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
1561{
1562	struct ftrace_page *pg;
1563	struct dyn_ftrace *rec = NULL;
1564	struct dyn_ftrace key;
1565
1566	key.ip = start;
1567	key.flags = end;	/* overload flags, as it is unsigned long */
1568
1569	for (pg = ftrace_pages_start; pg; pg = pg->next) {
1570		if (pg->index == 0 ||
1571		    end < pg->records[0].ip ||
1572		    start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1573			continue;
1574		rec = bsearch(&key, pg->records, pg->index,
1575			      sizeof(struct dyn_ftrace),
1576			      ftrace_cmp_recs);
1577		if (rec)
1578			break;
1579	}
1580	return rec;
1581}
1582
1583/**
1584 * ftrace_location_range - return the first address of a traced location
1585 *	if it touches the given ip range
1586 * @start: start of range to search.
1587 * @end: end of range to search (inclusive). @end points to the last byte
1588 *	to check.
1589 *
1590 * Returns rec->ip if the related ftrace location is a least partly within
1591 * the given address range. That is, the first address of the instruction
1592 * that is either a NOP or call to the function tracer. It checks the ftrace
1593 * internal tables to determine if the address belongs or not.
1594 */
1595unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1596{
1597	struct dyn_ftrace *rec;
1598
1599	rec = lookup_rec(start, end);
1600	if (rec)
1601		return rec->ip;
1602
1603	return 0;
1604}
1605
1606/**
1607 * ftrace_location - return the ftrace location
1608 * @ip: the instruction pointer to check
1609 *
1610 * If @ip matches the ftrace location, return @ip.
1611 * If @ip matches sym+0, return sym's ftrace location.
1612 * Otherwise, return 0.
1613 */
1614unsigned long ftrace_location(unsigned long ip)
1615{
1616	struct dyn_ftrace *rec;
1617	unsigned long offset;
1618	unsigned long size;
1619
1620	rec = lookup_rec(ip, ip);
1621	if (!rec) {
1622		if (!kallsyms_lookup_size_offset(ip, &size, &offset))
1623			goto out;
1624
1625		/* map sym+0 to __fentry__ */
1626		if (!offset)
1627			rec = lookup_rec(ip, ip + size - 1);
1628	}
1629
1630	if (rec)
1631		return rec->ip;
1632
1633out:
1634	return 0;
1635}
1636
1637/**
1638 * ftrace_text_reserved - return true if range contains an ftrace location
1639 * @start: start of range to search
1640 * @end: end of range to search (inclusive). @end points to the last byte to check.
1641 *
1642 * Returns 1 if @start and @end contains a ftrace location.
1643 * That is, the instruction that is either a NOP or call to
1644 * the function tracer. It checks the ftrace internal tables to
1645 * determine if the address belongs or not.
1646 */
1647int ftrace_text_reserved(const void *start, const void *end)
1648{
1649	unsigned long ret;
1650
1651	ret = ftrace_location_range((unsigned long)start,
1652				    (unsigned long)end);
1653
1654	return (int)!!ret;
1655}
1656
1657/* Test if ops registered to this rec needs regs */
1658static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1659{
1660	struct ftrace_ops *ops;
1661	bool keep_regs = false;
1662
1663	for (ops = ftrace_ops_list;
1664	     ops != &ftrace_list_end; ops = ops->next) {
1665		/* pass rec in as regs to have non-NULL val */
1666		if (ftrace_ops_test(ops, rec->ip, rec)) {
1667			if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1668				keep_regs = true;
1669				break;
1670			}
1671		}
1672	}
1673
1674	return  keep_regs;
1675}
1676
1677static struct ftrace_ops *
1678ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1679static struct ftrace_ops *
1680ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1681static struct ftrace_ops *
1682ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1683
1684static bool skip_record(struct dyn_ftrace *rec)
1685{
1686	/*
1687	 * At boot up, weak functions are set to disable. Function tracing
1688	 * can be enabled before they are, and they still need to be disabled now.
1689	 * If the record is disabled, still continue if it is marked as already
1690	 * enabled (this is needed to keep the accounting working).
1691	 */
1692	return rec->flags & FTRACE_FL_DISABLED &&
1693		!(rec->flags & FTRACE_FL_ENABLED);
1694}
1695
1696static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1697				     int filter_hash,
1698				     bool inc)
1699{
1700	struct ftrace_hash *hash;
1701	struct ftrace_hash *other_hash;
1702	struct ftrace_page *pg;
1703	struct dyn_ftrace *rec;
1704	bool update = false;
1705	int count = 0;
1706	int all = false;
1707
1708	/* Only update if the ops has been registered */
1709	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1710		return false;
1711
1712	/*
1713	 * In the filter_hash case:
1714	 *   If the count is zero, we update all records.
1715	 *   Otherwise we just update the items in the hash.
1716	 *
1717	 * In the notrace_hash case:
1718	 *   We enable the update in the hash.
1719	 *   As disabling notrace means enabling the tracing,
1720	 *   and enabling notrace means disabling, the inc variable
1721	 *   gets inversed.
1722	 */
1723	if (filter_hash) {
1724		hash = ops->func_hash->filter_hash;
1725		other_hash = ops->func_hash->notrace_hash;
1726		if (ftrace_hash_empty(hash))
1727			all = true;
1728	} else {
1729		inc = !inc;
1730		hash = ops->func_hash->notrace_hash;
1731		other_hash = ops->func_hash->filter_hash;
1732		/*
1733		 * If the notrace hash has no items,
1734		 * then there's nothing to do.
1735		 */
1736		if (ftrace_hash_empty(hash))
1737			return false;
1738	}
1739
1740	do_for_each_ftrace_rec(pg, rec) {
1741		int in_other_hash = 0;
1742		int in_hash = 0;
1743		int match = 0;
1744
1745		if (skip_record(rec))
1746			continue;
1747
1748		if (all) {
1749			/*
1750			 * Only the filter_hash affects all records.
1751			 * Update if the record is not in the notrace hash.
1752			 */
1753			if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1754				match = 1;
1755		} else {
1756			in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1757			in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1758
1759			/*
1760			 * If filter_hash is set, we want to match all functions
1761			 * that are in the hash but not in the other hash.
1762			 *
1763			 * If filter_hash is not set, then we are decrementing.
1764			 * That means we match anything that is in the hash
1765			 * and also in the other_hash. That is, we need to turn
1766			 * off functions in the other hash because they are disabled
1767			 * by this hash.
1768			 */
1769			if (filter_hash && in_hash && !in_other_hash)
1770				match = 1;
1771			else if (!filter_hash && in_hash &&
1772				 (in_other_hash || ftrace_hash_empty(other_hash)))
1773				match = 1;
1774		}
1775		if (!match)
1776			continue;
1777
1778		if (inc) {
1779			rec->flags++;
1780			if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1781				return false;
1782
1783			if (ops->flags & FTRACE_OPS_FL_DIRECT)
1784				rec->flags |= FTRACE_FL_DIRECT;
1785
1786			/*
1787			 * If there's only a single callback registered to a
1788			 * function, and the ops has a trampoline registered
1789			 * for it, then we can call it directly.
1790			 */
1791			if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1792				rec->flags |= FTRACE_FL_TRAMP;
1793			else
1794				/*
1795				 * If we are adding another function callback
1796				 * to this function, and the previous had a
1797				 * custom trampoline in use, then we need to go
1798				 * back to the default trampoline.
1799				 */
1800				rec->flags &= ~FTRACE_FL_TRAMP;
1801
1802			/*
1803			 * If any ops wants regs saved for this function
1804			 * then all ops will get saved regs.
1805			 */
1806			if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1807				rec->flags |= FTRACE_FL_REGS;
1808		} else {
1809			if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1810				return false;
1811			rec->flags--;
1812
1813			/*
1814			 * Only the internal direct_ops should have the
1815			 * DIRECT flag set. Thus, if it is removing a
1816			 * function, then that function should no longer
1817			 * be direct.
1818			 */
1819			if (ops->flags & FTRACE_OPS_FL_DIRECT)
1820				rec->flags &= ~FTRACE_FL_DIRECT;
1821
1822			/*
1823			 * If the rec had REGS enabled and the ops that is
1824			 * being removed had REGS set, then see if there is
1825			 * still any ops for this record that wants regs.
1826			 * If not, we can stop recording them.
1827			 */
1828			if (ftrace_rec_count(rec) > 0 &&
1829			    rec->flags & FTRACE_FL_REGS &&
1830			    ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1831				if (!test_rec_ops_needs_regs(rec))
1832					rec->flags &= ~FTRACE_FL_REGS;
1833			}
1834
1835			/*
1836			 * The TRAMP needs to be set only if rec count
1837			 * is decremented to one, and the ops that is
1838			 * left has a trampoline. As TRAMP can only be
1839			 * enabled if there is only a single ops attached
1840			 * to it.
1841			 */
1842			if (ftrace_rec_count(rec) == 1 &&
1843			    ftrace_find_tramp_ops_any_other(rec, ops))
1844				rec->flags |= FTRACE_FL_TRAMP;
1845			else
1846				rec->flags &= ~FTRACE_FL_TRAMP;
1847
1848			/*
1849			 * flags will be cleared in ftrace_check_record()
1850			 * if rec count is zero.
1851			 */
1852		}
1853
1854		/*
1855		 * If the rec has a single associated ops, and ops->func can be
1856		 * called directly, allow the call site to call via the ops.
1857		 */
1858		if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS) &&
1859		    ftrace_rec_count(rec) == 1 &&
1860		    ftrace_ops_get_func(ops) == ops->func)
1861			rec->flags |= FTRACE_FL_CALL_OPS;
1862		else
1863			rec->flags &= ~FTRACE_FL_CALL_OPS;
1864
1865		count++;
1866
1867		/* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1868		update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1869
1870		/* Shortcut, if we handled all records, we are done. */
1871		if (!all && count == hash->count)
1872			return update;
1873	} while_for_each_ftrace_rec();
1874
1875	return update;
1876}
1877
1878static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1879				    int filter_hash)
1880{
1881	return __ftrace_hash_rec_update(ops, filter_hash, 0);
1882}
1883
1884static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1885				   int filter_hash)
1886{
1887	return __ftrace_hash_rec_update(ops, filter_hash, 1);
1888}
1889
1890static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1891					  int filter_hash, int inc)
1892{
1893	struct ftrace_ops *op;
1894
1895	__ftrace_hash_rec_update(ops, filter_hash, inc);
1896
1897	if (ops->func_hash != &global_ops.local_hash)
1898		return;
1899
1900	/*
1901	 * If the ops shares the global_ops hash, then we need to update
1902	 * all ops that are enabled and use this hash.
1903	 */
1904	do_for_each_ftrace_op(op, ftrace_ops_list) {
1905		/* Already done */
1906		if (op == ops)
1907			continue;
1908		if (op->func_hash == &global_ops.local_hash)
1909			__ftrace_hash_rec_update(op, filter_hash, inc);
1910	} while_for_each_ftrace_op(op);
1911}
1912
1913static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1914					   int filter_hash)
1915{
1916	ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1917}
1918
1919static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1920					  int filter_hash)
1921{
1922	ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1923}
1924
1925/*
1926 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1927 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1928 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1929 * Note that old_hash and new_hash has below meanings
1930 *  - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1931 *  - If the hash is EMPTY_HASH, it hits nothing
1932 *  - Anything else hits the recs which match the hash entries.
1933 *
1934 * DIRECT ops does not have IPMODIFY flag, but we still need to check it
1935 * against functions with FTRACE_FL_IPMODIFY. If there is any overlap, call
1936 * ops_func(SHARE_IPMODIFY_SELF) to make sure current ops can share with
1937 * IPMODIFY. If ops_func(SHARE_IPMODIFY_SELF) returns non-zero, propagate
1938 * the return value to the caller and eventually to the owner of the DIRECT
1939 * ops.
1940 */
1941static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1942					 struct ftrace_hash *old_hash,
1943					 struct ftrace_hash *new_hash)
1944{
1945	struct ftrace_page *pg;
1946	struct dyn_ftrace *rec, *end = NULL;
1947	int in_old, in_new;
1948	bool is_ipmodify, is_direct;
1949
1950	/* Only update if the ops has been registered */
1951	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1952		return 0;
1953
1954	is_ipmodify = ops->flags & FTRACE_OPS_FL_IPMODIFY;
1955	is_direct = ops->flags & FTRACE_OPS_FL_DIRECT;
1956
1957	/* neither IPMODIFY nor DIRECT, skip */
1958	if (!is_ipmodify && !is_direct)
1959		return 0;
1960
1961	if (WARN_ON_ONCE(is_ipmodify && is_direct))
1962		return 0;
1963
1964	/*
1965	 * Since the IPMODIFY and DIRECT are very address sensitive
1966	 * actions, we do not allow ftrace_ops to set all functions to new
1967	 * hash.
1968	 */
1969	if (!new_hash || !old_hash)
1970		return -EINVAL;
1971
1972	/* Update rec->flags */
1973	do_for_each_ftrace_rec(pg, rec) {
1974
1975		if (rec->flags & FTRACE_FL_DISABLED)
1976			continue;
1977
1978		/* We need to update only differences of filter_hash */
1979		in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1980		in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1981		if (in_old == in_new)
1982			continue;
1983
1984		if (in_new) {
1985			if (rec->flags & FTRACE_FL_IPMODIFY) {
1986				int ret;
1987
1988				/* Cannot have two ipmodify on same rec */
1989				if (is_ipmodify)
1990					goto rollback;
1991
1992				FTRACE_WARN_ON(rec->flags & FTRACE_FL_DIRECT);
1993
1994				/*
1995				 * Another ops with IPMODIFY is already
1996				 * attached. We are now attaching a direct
1997				 * ops. Run SHARE_IPMODIFY_SELF, to check
1998				 * whether sharing is supported.
1999				 */
2000				if (!ops->ops_func)
2001					return -EBUSY;
2002				ret = ops->ops_func(ops, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF);
2003				if (ret)
2004					return ret;
2005			} else if (is_ipmodify) {
2006				rec->flags |= FTRACE_FL_IPMODIFY;
2007			}
2008		} else if (is_ipmodify) {
2009			rec->flags &= ~FTRACE_FL_IPMODIFY;
2010		}
2011	} while_for_each_ftrace_rec();
2012
2013	return 0;
2014
2015rollback:
2016	end = rec;
2017
2018	/* Roll back what we did above */
2019	do_for_each_ftrace_rec(pg, rec) {
2020
2021		if (rec->flags & FTRACE_FL_DISABLED)
2022			continue;
2023
2024		if (rec == end)
2025			goto err_out;
2026
2027		in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
2028		in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
2029		if (in_old == in_new)
2030			continue;
2031
2032		if (in_new)
2033			rec->flags &= ~FTRACE_FL_IPMODIFY;
2034		else
2035			rec->flags |= FTRACE_FL_IPMODIFY;
2036	} while_for_each_ftrace_rec();
2037
2038err_out:
2039	return -EBUSY;
2040}
2041
2042static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
2043{
2044	struct ftrace_hash *hash = ops->func_hash->filter_hash;
2045
2046	if (ftrace_hash_empty(hash))
2047		hash = NULL;
2048
2049	return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
2050}
2051
2052/* Disabling always succeeds */
2053static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
2054{
2055	struct ftrace_hash *hash = ops->func_hash->filter_hash;
2056
2057	if (ftrace_hash_empty(hash))
2058		hash = NULL;
2059
2060	__ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
2061}
2062
2063static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
2064				       struct ftrace_hash *new_hash)
2065{
2066	struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
2067
2068	if (ftrace_hash_empty(old_hash))
2069		old_hash = NULL;
2070
2071	if (ftrace_hash_empty(new_hash))
2072		new_hash = NULL;
2073
2074	return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
2075}
2076
2077static void print_ip_ins(const char *fmt, const unsigned char *p)
2078{
2079	char ins[MCOUNT_INSN_SIZE];
2080
2081	if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
2082		printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
2083		return;
2084	}
2085
2086	printk(KERN_CONT "%s", fmt);
2087	pr_cont("%*phC", MCOUNT_INSN_SIZE, ins);
2088}
2089
2090enum ftrace_bug_type ftrace_bug_type;
2091const void *ftrace_expected;
2092
2093static void print_bug_type(void)
2094{
2095	switch (ftrace_bug_type) {
2096	case FTRACE_BUG_UNKNOWN:
2097		break;
2098	case FTRACE_BUG_INIT:
2099		pr_info("Initializing ftrace call sites\n");
2100		break;
2101	case FTRACE_BUG_NOP:
2102		pr_info("Setting ftrace call site to NOP\n");
2103		break;
2104	case FTRACE_BUG_CALL:
2105		pr_info("Setting ftrace call site to call ftrace function\n");
2106		break;
2107	case FTRACE_BUG_UPDATE:
2108		pr_info("Updating ftrace call site to call a different ftrace function\n");
2109		break;
2110	}
2111}
2112
2113/**
2114 * ftrace_bug - report and shutdown function tracer
2115 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2116 * @rec: The record that failed
2117 *
2118 * The arch code that enables or disables the function tracing
2119 * can call ftrace_bug() when it has detected a problem in
2120 * modifying the code. @failed should be one of either:
2121 * EFAULT - if the problem happens on reading the @ip address
2122 * EINVAL - if what is read at @ip is not what was expected
2123 * EPERM - if the problem happens on writing to the @ip address
2124 */
2125void ftrace_bug(int failed, struct dyn_ftrace *rec)
2126{
2127	unsigned long ip = rec ? rec->ip : 0;
2128
2129	pr_info("------------[ ftrace bug ]------------\n");
2130
2131	switch (failed) {
2132	case -EFAULT:
2133		pr_info("ftrace faulted on modifying ");
2134		print_ip_sym(KERN_INFO, ip);
2135		break;
2136	case -EINVAL:
2137		pr_info("ftrace failed to modify ");
2138		print_ip_sym(KERN_INFO, ip);
2139		print_ip_ins(" actual:   ", (unsigned char *)ip);
2140		pr_cont("\n");
2141		if (ftrace_expected) {
2142			print_ip_ins(" expected: ", ftrace_expected);
2143			pr_cont("\n");
2144		}
2145		break;
2146	case -EPERM:
2147		pr_info("ftrace faulted on writing ");
2148		print_ip_sym(KERN_INFO, ip);
2149		break;
2150	default:
2151		pr_info("ftrace faulted on unknown error ");
2152		print_ip_sym(KERN_INFO, ip);
2153	}
2154	print_bug_type();
2155	if (rec) {
2156		struct ftrace_ops *ops = NULL;
2157
2158		pr_info("ftrace record flags: %lx\n", rec->flags);
2159		pr_cont(" (%ld)%s%s", ftrace_rec_count(rec),
2160			rec->flags & FTRACE_FL_REGS ? " R" : "  ",
2161			rec->flags & FTRACE_FL_CALL_OPS ? " O" : "  ");
2162		if (rec->flags & FTRACE_FL_TRAMP_EN) {
2163			ops = ftrace_find_tramp_ops_any(rec);
2164			if (ops) {
2165				do {
2166					pr_cont("\ttramp: %pS (%pS)",
2167						(void *)ops->trampoline,
2168						(void *)ops->func);
2169					ops = ftrace_find_tramp_ops_next(rec, ops);
2170				} while (ops);
2171			} else
2172				pr_cont("\ttramp: ERROR!");
2173
2174		}
2175		ip = ftrace_get_addr_curr(rec);
2176		pr_cont("\n expected tramp: %lx\n", ip);
2177	}
2178
2179	FTRACE_WARN_ON_ONCE(1);
2180}
2181
2182static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2183{
2184	unsigned long flag = 0UL;
2185
2186	ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2187
2188	if (skip_record(rec))
2189		return FTRACE_UPDATE_IGNORE;
2190
2191	/*
2192	 * If we are updating calls:
2193	 *
2194	 *   If the record has a ref count, then we need to enable it
2195	 *   because someone is using it.
2196	 *
2197	 *   Otherwise we make sure its disabled.
2198	 *
2199	 * If we are disabling calls, then disable all records that
2200	 * are enabled.
2201	 */
2202	if (enable && ftrace_rec_count(rec))
2203		flag = FTRACE_FL_ENABLED;
2204
2205	/*
2206	 * If enabling and the REGS flag does not match the REGS_EN, or
2207	 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2208	 * this record. Set flags to fail the compare against ENABLED.
2209	 * Same for direct calls.
2210	 */
2211	if (flag) {
2212		if (!(rec->flags & FTRACE_FL_REGS) !=
2213		    !(rec->flags & FTRACE_FL_REGS_EN))
2214			flag |= FTRACE_FL_REGS;
2215
2216		if (!(rec->flags & FTRACE_FL_TRAMP) !=
2217		    !(rec->flags & FTRACE_FL_TRAMP_EN))
2218			flag |= FTRACE_FL_TRAMP;
2219
2220		/*
2221		 * Direct calls are special, as count matters.
2222		 * We must test the record for direct, if the
2223		 * DIRECT and DIRECT_EN do not match, but only
2224		 * if the count is 1. That's because, if the
2225		 * count is something other than one, we do not
2226		 * want the direct enabled (it will be done via the
2227		 * direct helper). But if DIRECT_EN is set, and
2228		 * the count is not one, we need to clear it.
2229		 *
2230		 */
2231		if (ftrace_rec_count(rec) == 1) {
2232			if (!(rec->flags & FTRACE_FL_DIRECT) !=
2233			    !(rec->flags & FTRACE_FL_DIRECT_EN))
2234				flag |= FTRACE_FL_DIRECT;
2235		} else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2236			flag |= FTRACE_FL_DIRECT;
2237		}
2238
2239		/*
2240		 * Ops calls are special, as count matters.
2241		 * As with direct calls, they must only be enabled when count
2242		 * is one, otherwise they'll be handled via the list ops.
2243		 */
2244		if (ftrace_rec_count(rec) == 1) {
2245			if (!(rec->flags & FTRACE_FL_CALL_OPS) !=
2246			    !(rec->flags & FTRACE_FL_CALL_OPS_EN))
2247				flag |= FTRACE_FL_CALL_OPS;
2248		} else if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
2249			flag |= FTRACE_FL_CALL_OPS;
2250		}
2251	}
2252
2253	/* If the state of this record hasn't changed, then do nothing */
2254	if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2255		return FTRACE_UPDATE_IGNORE;
2256
2257	if (flag) {
2258		/* Save off if rec is being enabled (for return value) */
2259		flag ^= rec->flags & FTRACE_FL_ENABLED;
2260
2261		if (update) {
2262			rec->flags |= FTRACE_FL_ENABLED | FTRACE_FL_TOUCHED;
2263			if (flag & FTRACE_FL_REGS) {
2264				if (rec->flags & FTRACE_FL_REGS)
2265					rec->flags |= FTRACE_FL_REGS_EN;
2266				else
2267					rec->flags &= ~FTRACE_FL_REGS_EN;
2268			}
2269			if (flag & FTRACE_FL_TRAMP) {
2270				if (rec->flags & FTRACE_FL_TRAMP)
2271					rec->flags |= FTRACE_FL_TRAMP_EN;
2272				else
2273					rec->flags &= ~FTRACE_FL_TRAMP_EN;
2274			}
2275
2276			/* Keep track of anything that modifies the function */
2277			if (rec->flags & (FTRACE_FL_DIRECT | FTRACE_FL_IPMODIFY))
2278				rec->flags |= FTRACE_FL_MODIFIED;
2279
2280			if (flag & FTRACE_FL_DIRECT) {
2281				/*
2282				 * If there's only one user (direct_ops helper)
2283				 * then we can call the direct function
2284				 * directly (no ftrace trampoline).
2285				 */
2286				if (ftrace_rec_count(rec) == 1) {
2287					if (rec->flags & FTRACE_FL_DIRECT)
2288						rec->flags |= FTRACE_FL_DIRECT_EN;
2289					else
2290						rec->flags &= ~FTRACE_FL_DIRECT_EN;
2291				} else {
2292					/*
2293					 * Can only call directly if there's
2294					 * only one callback to the function.
2295					 */
2296					rec->flags &= ~FTRACE_FL_DIRECT_EN;
2297				}
2298			}
2299
2300			if (flag & FTRACE_FL_CALL_OPS) {
2301				if (ftrace_rec_count(rec) == 1) {
2302					if (rec->flags & FTRACE_FL_CALL_OPS)
2303						rec->flags |= FTRACE_FL_CALL_OPS_EN;
2304					else
2305						rec->flags &= ~FTRACE_FL_CALL_OPS_EN;
2306				} else {
2307					/*
2308					 * Can only call directly if there's
2309					 * only one set of associated ops.
2310					 */
2311					rec->flags &= ~FTRACE_FL_CALL_OPS_EN;
2312				}
2313			}
2314		}
2315
2316		/*
2317		 * If this record is being updated from a nop, then
2318		 *   return UPDATE_MAKE_CALL.
2319		 * Otherwise,
2320		 *   return UPDATE_MODIFY_CALL to tell the caller to convert
2321		 *   from the save regs, to a non-save regs function or
2322		 *   vice versa, or from a trampoline call.
2323		 */
2324		if (flag & FTRACE_FL_ENABLED) {
2325			ftrace_bug_type = FTRACE_BUG_CALL;
2326			return FTRACE_UPDATE_MAKE_CALL;
2327		}
2328
2329		ftrace_bug_type = FTRACE_BUG_UPDATE;
2330		return FTRACE_UPDATE_MODIFY_CALL;
2331	}
2332
2333	if (update) {
2334		/* If there's no more users, clear all flags */
2335		if (!ftrace_rec_count(rec))
2336			rec->flags &= FTRACE_NOCLEAR_FLAGS;
2337		else
2338			/*
2339			 * Just disable the record, but keep the ops TRAMP
2340			 * and REGS states. The _EN flags must be disabled though.
2341			 */
2342			rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2343					FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN |
2344					FTRACE_FL_CALL_OPS_EN);
2345	}
2346
2347	ftrace_bug_type = FTRACE_BUG_NOP;
2348	return FTRACE_UPDATE_MAKE_NOP;
2349}
2350
2351/**
2352 * ftrace_update_record - set a record that now is tracing or not
2353 * @rec: the record to update
2354 * @enable: set to true if the record is tracing, false to force disable
2355 *
2356 * The records that represent all functions that can be traced need
2357 * to be updated when tracing has been enabled.
2358 */
2359int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2360{
2361	return ftrace_check_record(rec, enable, true);
2362}
2363
2364/**
2365 * ftrace_test_record - check if the record has been enabled or not
2366 * @rec: the record to test
2367 * @enable: set to true to check if enabled, false if it is disabled
2368 *
2369 * The arch code may need to test if a record is already set to
2370 * tracing to determine how to modify the function code that it
2371 * represents.
2372 */
2373int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2374{
2375	return ftrace_check_record(rec, enable, false);
2376}
2377
2378static struct ftrace_ops *
2379ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2380{
2381	struct ftrace_ops *op;
2382	unsigned long ip = rec->ip;
2383
2384	do_for_each_ftrace_op(op, ftrace_ops_list) {
2385
2386		if (!op->trampoline)
2387			continue;
2388
2389		if (hash_contains_ip(ip, op->func_hash))
2390			return op;
2391	} while_for_each_ftrace_op(op);
2392
2393	return NULL;
2394}
2395
2396static struct ftrace_ops *
2397ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2398{
2399	struct ftrace_ops *op;
2400	unsigned long ip = rec->ip;
2401
2402	do_for_each_ftrace_op(op, ftrace_ops_list) {
2403
2404		if (op == op_exclude || !op->trampoline)
2405			continue;
2406
2407		if (hash_contains_ip(ip, op->func_hash))
2408			return op;
2409	} while_for_each_ftrace_op(op);
2410
2411	return NULL;
2412}
2413
2414static struct ftrace_ops *
2415ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2416			   struct ftrace_ops *op)
2417{
2418	unsigned long ip = rec->ip;
2419
2420	while_for_each_ftrace_op(op) {
2421
2422		if (!op->trampoline)
2423			continue;
2424
2425		if (hash_contains_ip(ip, op->func_hash))
2426			return op;
2427	}
2428
2429	return NULL;
2430}
2431
2432static struct ftrace_ops *
2433ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2434{
2435	struct ftrace_ops *op;
2436	unsigned long ip = rec->ip;
2437
2438	/*
2439	 * Need to check removed ops first.
2440	 * If they are being removed, and this rec has a tramp,
2441	 * and this rec is in the ops list, then it would be the
2442	 * one with the tramp.
2443	 */
2444	if (removed_ops) {
2445		if (hash_contains_ip(ip, &removed_ops->old_hash))
2446			return removed_ops;
2447	}
2448
2449	/*
2450	 * Need to find the current trampoline for a rec.
2451	 * Now, a trampoline is only attached to a rec if there
2452	 * was a single 'ops' attached to it. But this can be called
2453	 * when we are adding another op to the rec or removing the
2454	 * current one. Thus, if the op is being added, we can
2455	 * ignore it because it hasn't attached itself to the rec
2456	 * yet.
2457	 *
2458	 * If an ops is being modified (hooking to different functions)
2459	 * then we don't care about the new functions that are being
2460	 * added, just the old ones (that are probably being removed).
2461	 *
2462	 * If we are adding an ops to a function that already is using
2463	 * a trampoline, it needs to be removed (trampolines are only
2464	 * for single ops connected), then an ops that is not being
2465	 * modified also needs to be checked.
2466	 */
2467	do_for_each_ftrace_op(op, ftrace_ops_list) {
2468
2469		if (!op->trampoline)
2470			continue;
2471
2472		/*
2473		 * If the ops is being added, it hasn't gotten to
2474		 * the point to be removed from this tree yet.
2475		 */
2476		if (op->flags & FTRACE_OPS_FL_ADDING)
2477			continue;
2478
2479
2480		/*
2481		 * If the ops is being modified and is in the old
2482		 * hash, then it is probably being removed from this
2483		 * function.
2484		 */
2485		if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2486		    hash_contains_ip(ip, &op->old_hash))
2487			return op;
2488		/*
2489		 * If the ops is not being added or modified, and it's
2490		 * in its normal filter hash, then this must be the one
2491		 * we want!
2492		 */
2493		if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2494		    hash_contains_ip(ip, op->func_hash))
2495			return op;
2496
2497	} while_for_each_ftrace_op(op);
2498
2499	return NULL;
2500}
2501
2502static struct ftrace_ops *
2503ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2504{
2505	struct ftrace_ops *op;
2506	unsigned long ip = rec->ip;
2507
2508	do_for_each_ftrace_op(op, ftrace_ops_list) {
2509		/* pass rec in as regs to have non-NULL val */
2510		if (hash_contains_ip(ip, op->func_hash))
2511			return op;
2512	} while_for_each_ftrace_op(op);
2513
2514	return NULL;
2515}
2516
2517struct ftrace_ops *
2518ftrace_find_unique_ops(struct dyn_ftrace *rec)
2519{
2520	struct ftrace_ops *op, *found = NULL;
2521	unsigned long ip = rec->ip;
2522
2523	do_for_each_ftrace_op(op, ftrace_ops_list) {
2524
2525		if (hash_contains_ip(ip, op->func_hash)) {
2526			if (found)
2527				return NULL;
2528			found = op;
2529		}
2530
2531	} while_for_each_ftrace_op(op);
2532
2533	return found;
2534}
2535
2536#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2537/* Protected by rcu_tasks for reading, and direct_mutex for writing */
2538static struct ftrace_hash __rcu *direct_functions = EMPTY_HASH;
2539static DEFINE_MUTEX(direct_mutex);
2540int ftrace_direct_func_count;
2541
2542/*
2543 * Search the direct_functions hash to see if the given instruction pointer
2544 * has a direct caller attached to it.
2545 */
2546unsigned long ftrace_find_rec_direct(unsigned long ip)
2547{
2548	struct ftrace_func_entry *entry;
2549
2550	entry = __ftrace_lookup_ip(direct_functions, ip);
2551	if (!entry)
2552		return 0;
2553
2554	return entry->direct;
2555}
2556
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2557static void call_direct_funcs(unsigned long ip, unsigned long pip,
2558			      struct ftrace_ops *ops, struct ftrace_regs *fregs)
2559{
2560	unsigned long addr = READ_ONCE(ops->direct_call);
2561
 
2562	if (!addr)
2563		return;
2564
2565	arch_ftrace_set_direct_caller(fregs, addr);
2566}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2567#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2568
2569/**
2570 * ftrace_get_addr_new - Get the call address to set to
2571 * @rec:  The ftrace record descriptor
2572 *
2573 * If the record has the FTRACE_FL_REGS set, that means that it
2574 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2575 * is not set, then it wants to convert to the normal callback.
2576 *
2577 * Returns the address of the trampoline to set to
2578 */
2579unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2580{
2581	struct ftrace_ops *ops;
2582	unsigned long addr;
2583
2584	if ((rec->flags & FTRACE_FL_DIRECT) &&
2585	    (ftrace_rec_count(rec) == 1)) {
2586		addr = ftrace_find_rec_direct(rec->ip);
2587		if (addr)
2588			return addr;
2589		WARN_ON_ONCE(1);
2590	}
2591
2592	/* Trampolines take precedence over regs */
2593	if (rec->flags & FTRACE_FL_TRAMP) {
2594		ops = ftrace_find_tramp_ops_new(rec);
2595		if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2596			pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2597				(void *)rec->ip, (void *)rec->ip, rec->flags);
2598			/* Ftrace is shutting down, return anything */
2599			return (unsigned long)FTRACE_ADDR;
2600		}
2601		return ops->trampoline;
2602	}
2603
2604	if (rec->flags & FTRACE_FL_REGS)
2605		return (unsigned long)FTRACE_REGS_ADDR;
2606	else
2607		return (unsigned long)FTRACE_ADDR;
2608}
2609
2610/**
2611 * ftrace_get_addr_curr - Get the call address that is already there
2612 * @rec:  The ftrace record descriptor
2613 *
2614 * The FTRACE_FL_REGS_EN is set when the record already points to
2615 * a function that saves all the regs. Basically the '_EN' version
2616 * represents the current state of the function.
2617 *
2618 * Returns the address of the trampoline that is currently being called
2619 */
2620unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2621{
2622	struct ftrace_ops *ops;
2623	unsigned long addr;
2624
2625	/* Direct calls take precedence over trampolines */
2626	if (rec->flags & FTRACE_FL_DIRECT_EN) {
2627		addr = ftrace_find_rec_direct(rec->ip);
2628		if (addr)
2629			return addr;
2630		WARN_ON_ONCE(1);
2631	}
2632
2633	/* Trampolines take precedence over regs */
2634	if (rec->flags & FTRACE_FL_TRAMP_EN) {
2635		ops = ftrace_find_tramp_ops_curr(rec);
2636		if (FTRACE_WARN_ON(!ops)) {
2637			pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2638				(void *)rec->ip, (void *)rec->ip);
2639			/* Ftrace is shutting down, return anything */
2640			return (unsigned long)FTRACE_ADDR;
2641		}
2642		return ops->trampoline;
2643	}
2644
2645	if (rec->flags & FTRACE_FL_REGS_EN)
2646		return (unsigned long)FTRACE_REGS_ADDR;
2647	else
2648		return (unsigned long)FTRACE_ADDR;
2649}
2650
2651static int
2652__ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2653{
2654	unsigned long ftrace_old_addr;
2655	unsigned long ftrace_addr;
2656	int ret;
2657
2658	ftrace_addr = ftrace_get_addr_new(rec);
2659
2660	/* This needs to be done before we call ftrace_update_record */
2661	ftrace_old_addr = ftrace_get_addr_curr(rec);
2662
2663	ret = ftrace_update_record(rec, enable);
2664
2665	ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2666
2667	switch (ret) {
2668	case FTRACE_UPDATE_IGNORE:
2669		return 0;
2670
2671	case FTRACE_UPDATE_MAKE_CALL:
2672		ftrace_bug_type = FTRACE_BUG_CALL;
2673		return ftrace_make_call(rec, ftrace_addr);
2674
2675	case FTRACE_UPDATE_MAKE_NOP:
2676		ftrace_bug_type = FTRACE_BUG_NOP;
2677		return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2678
2679	case FTRACE_UPDATE_MODIFY_CALL:
2680		ftrace_bug_type = FTRACE_BUG_UPDATE;
2681		return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2682	}
2683
2684	return -1; /* unknown ftrace bug */
2685}
2686
2687void __weak ftrace_replace_code(int mod_flags)
2688{
2689	struct dyn_ftrace *rec;
2690	struct ftrace_page *pg;
2691	bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2692	int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2693	int failed;
2694
2695	if (unlikely(ftrace_disabled))
2696		return;
2697
2698	do_for_each_ftrace_rec(pg, rec) {
2699
2700		if (skip_record(rec))
2701			continue;
2702
2703		failed = __ftrace_replace_code(rec, enable);
2704		if (failed) {
2705			ftrace_bug(failed, rec);
2706			/* Stop processing */
2707			return;
2708		}
2709		if (schedulable)
2710			cond_resched();
2711	} while_for_each_ftrace_rec();
2712}
2713
2714struct ftrace_rec_iter {
2715	struct ftrace_page	*pg;
2716	int			index;
2717};
2718
2719/**
2720 * ftrace_rec_iter_start - start up iterating over traced functions
2721 *
2722 * Returns an iterator handle that is used to iterate over all
2723 * the records that represent address locations where functions
2724 * are traced.
2725 *
2726 * May return NULL if no records are available.
2727 */
2728struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2729{
2730	/*
2731	 * We only use a single iterator.
2732	 * Protected by the ftrace_lock mutex.
2733	 */
2734	static struct ftrace_rec_iter ftrace_rec_iter;
2735	struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2736
2737	iter->pg = ftrace_pages_start;
2738	iter->index = 0;
2739
2740	/* Could have empty pages */
2741	while (iter->pg && !iter->pg->index)
2742		iter->pg = iter->pg->next;
2743
2744	if (!iter->pg)
2745		return NULL;
2746
2747	return iter;
2748}
2749
2750/**
2751 * ftrace_rec_iter_next - get the next record to process.
2752 * @iter: The handle to the iterator.
2753 *
2754 * Returns the next iterator after the given iterator @iter.
2755 */
2756struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2757{
2758	iter->index++;
2759
2760	if (iter->index >= iter->pg->index) {
2761		iter->pg = iter->pg->next;
2762		iter->index = 0;
2763
2764		/* Could have empty pages */
2765		while (iter->pg && !iter->pg->index)
2766			iter->pg = iter->pg->next;
2767	}
2768
2769	if (!iter->pg)
2770		return NULL;
2771
2772	return iter;
2773}
2774
2775/**
2776 * ftrace_rec_iter_record - get the record at the iterator location
2777 * @iter: The current iterator location
2778 *
2779 * Returns the record that the current @iter is at.
2780 */
2781struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2782{
2783	return &iter->pg->records[iter->index];
2784}
2785
2786static int
2787ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2788{
2789	int ret;
2790
2791	if (unlikely(ftrace_disabled))
2792		return 0;
2793
2794	ret = ftrace_init_nop(mod, rec);
2795	if (ret) {
2796		ftrace_bug_type = FTRACE_BUG_INIT;
2797		ftrace_bug(ret, rec);
2798		return 0;
2799	}
2800	return 1;
2801}
2802
2803/*
2804 * archs can override this function if they must do something
2805 * before the modifying code is performed.
2806 */
2807void __weak ftrace_arch_code_modify_prepare(void)
2808{
2809}
2810
2811/*
2812 * archs can override this function if they must do something
2813 * after the modifying code is performed.
2814 */
2815void __weak ftrace_arch_code_modify_post_process(void)
2816{
2817}
2818
2819static int update_ftrace_func(ftrace_func_t func)
2820{
2821	static ftrace_func_t save_func;
2822
2823	/* Avoid updating if it hasn't changed */
2824	if (func == save_func)
2825		return 0;
2826
2827	save_func = func;
2828
2829	return ftrace_update_ftrace_func(func);
2830}
2831
2832void ftrace_modify_all_code(int command)
2833{
2834	int update = command & FTRACE_UPDATE_TRACE_FUNC;
2835	int mod_flags = 0;
2836	int err = 0;
2837
2838	if (command & FTRACE_MAY_SLEEP)
2839		mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2840
2841	/*
2842	 * If the ftrace_caller calls a ftrace_ops func directly,
2843	 * we need to make sure that it only traces functions it
2844	 * expects to trace. When doing the switch of functions,
2845	 * we need to update to the ftrace_ops_list_func first
2846	 * before the transition between old and new calls are set,
2847	 * as the ftrace_ops_list_func will check the ops hashes
2848	 * to make sure the ops are having the right functions
2849	 * traced.
2850	 */
2851	if (update) {
2852		err = update_ftrace_func(ftrace_ops_list_func);
2853		if (FTRACE_WARN_ON(err))
2854			return;
2855	}
2856
2857	if (command & FTRACE_UPDATE_CALLS)
2858		ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2859	else if (command & FTRACE_DISABLE_CALLS)
2860		ftrace_replace_code(mod_flags);
2861
2862	if (update && ftrace_trace_function != ftrace_ops_list_func) {
2863		function_trace_op = set_function_trace_op;
2864		smp_wmb();
2865		/* If irqs are disabled, we are in stop machine */
2866		if (!irqs_disabled())
2867			smp_call_function(ftrace_sync_ipi, NULL, 1);
2868		err = update_ftrace_func(ftrace_trace_function);
2869		if (FTRACE_WARN_ON(err))
2870			return;
2871	}
2872
2873	if (command & FTRACE_START_FUNC_RET)
2874		err = ftrace_enable_ftrace_graph_caller();
2875	else if (command & FTRACE_STOP_FUNC_RET)
2876		err = ftrace_disable_ftrace_graph_caller();
2877	FTRACE_WARN_ON(err);
2878}
2879
2880static int __ftrace_modify_code(void *data)
2881{
2882	int *command = data;
2883
2884	ftrace_modify_all_code(*command);
2885
2886	return 0;
2887}
2888
2889/**
2890 * ftrace_run_stop_machine - go back to the stop machine method
2891 * @command: The command to tell ftrace what to do
2892 *
2893 * If an arch needs to fall back to the stop machine method, the
2894 * it can call this function.
2895 */
2896void ftrace_run_stop_machine(int command)
2897{
2898	stop_machine(__ftrace_modify_code, &command, NULL);
2899}
2900
2901/**
2902 * arch_ftrace_update_code - modify the code to trace or not trace
2903 * @command: The command that needs to be done
2904 *
2905 * Archs can override this function if it does not need to
2906 * run stop_machine() to modify code.
2907 */
2908void __weak arch_ftrace_update_code(int command)
2909{
2910	ftrace_run_stop_machine(command);
2911}
2912
2913static void ftrace_run_update_code(int command)
2914{
2915	ftrace_arch_code_modify_prepare();
2916
2917	/*
2918	 * By default we use stop_machine() to modify the code.
2919	 * But archs can do what ever they want as long as it
2920	 * is safe. The stop_machine() is the safest, but also
2921	 * produces the most overhead.
2922	 */
2923	arch_ftrace_update_code(command);
2924
2925	ftrace_arch_code_modify_post_process();
2926}
2927
2928static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2929				   struct ftrace_ops_hash *old_hash)
2930{
2931	ops->flags |= FTRACE_OPS_FL_MODIFYING;
2932	ops->old_hash.filter_hash = old_hash->filter_hash;
2933	ops->old_hash.notrace_hash = old_hash->notrace_hash;
2934	ftrace_run_update_code(command);
2935	ops->old_hash.filter_hash = NULL;
2936	ops->old_hash.notrace_hash = NULL;
2937	ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2938}
2939
2940static ftrace_func_t saved_ftrace_func;
2941static int ftrace_start_up;
2942
2943void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2944{
2945}
2946
2947/* List of trace_ops that have allocated trampolines */
2948static LIST_HEAD(ftrace_ops_trampoline_list);
2949
2950static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2951{
2952	lockdep_assert_held(&ftrace_lock);
2953	list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2954}
2955
2956static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2957{
2958	lockdep_assert_held(&ftrace_lock);
2959	list_del_rcu(&ops->list);
2960	synchronize_rcu();
2961}
2962
2963/*
2964 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2965 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2966 * not a module.
2967 */
2968#define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2969#define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2970
2971static void ftrace_trampoline_free(struct ftrace_ops *ops)
2972{
2973	if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
2974	    ops->trampoline) {
2975		/*
2976		 * Record the text poke event before the ksymbol unregister
2977		 * event.
2978		 */
2979		perf_event_text_poke((void *)ops->trampoline,
2980				     (void *)ops->trampoline,
2981				     ops->trampoline_size, NULL, 0);
2982		perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
2983				   ops->trampoline, ops->trampoline_size,
2984				   true, FTRACE_TRAMPOLINE_SYM);
2985		/* Remove from kallsyms after the perf events */
2986		ftrace_remove_trampoline_from_kallsyms(ops);
2987	}
2988
2989	arch_ftrace_trampoline_free(ops);
2990}
2991
2992static void ftrace_startup_enable(int command)
2993{
2994	if (saved_ftrace_func != ftrace_trace_function) {
2995		saved_ftrace_func = ftrace_trace_function;
2996		command |= FTRACE_UPDATE_TRACE_FUNC;
2997	}
2998
2999	if (!command || !ftrace_enabled)
3000		return;
3001
3002	ftrace_run_update_code(command);
3003}
3004
3005static void ftrace_startup_all(int command)
3006{
3007	update_all_ops = true;
3008	ftrace_startup_enable(command);
3009	update_all_ops = false;
3010}
3011
3012int ftrace_startup(struct ftrace_ops *ops, int command)
3013{
3014	int ret;
3015
3016	if (unlikely(ftrace_disabled))
3017		return -ENODEV;
3018
3019	ret = __register_ftrace_function(ops);
3020	if (ret)
3021		return ret;
3022
3023	ftrace_start_up++;
3024
3025	/*
3026	 * Note that ftrace probes uses this to start up
3027	 * and modify functions it will probe. But we still
3028	 * set the ADDING flag for modification, as probes
3029	 * do not have trampolines. If they add them in the
3030	 * future, then the probes will need to distinguish
3031	 * between adding and updating probes.
3032	 */
3033	ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
3034
3035	ret = ftrace_hash_ipmodify_enable(ops);
3036	if (ret < 0) {
3037		/* Rollback registration process */
3038		__unregister_ftrace_function(ops);
3039		ftrace_start_up--;
3040		ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3041		if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
3042			ftrace_trampoline_free(ops);
3043		return ret;
3044	}
3045
3046	if (ftrace_hash_rec_enable(ops, 1))
3047		command |= FTRACE_UPDATE_CALLS;
3048
3049	ftrace_startup_enable(command);
3050
3051	/*
3052	 * If ftrace is in an undefined state, we just remove ops from list
3053	 * to prevent the NULL pointer, instead of totally rolling it back and
3054	 * free trampoline, because those actions could cause further damage.
3055	 */
3056	if (unlikely(ftrace_disabled)) {
3057		__unregister_ftrace_function(ops);
3058		return -ENODEV;
3059	}
3060
3061	ops->flags &= ~FTRACE_OPS_FL_ADDING;
3062
3063	return 0;
3064}
3065
3066int ftrace_shutdown(struct ftrace_ops *ops, int command)
3067{
3068	int ret;
3069
3070	if (unlikely(ftrace_disabled))
3071		return -ENODEV;
3072
3073	ret = __unregister_ftrace_function(ops);
3074	if (ret)
3075		return ret;
3076
3077	ftrace_start_up--;
3078	/*
3079	 * Just warn in case of unbalance, no need to kill ftrace, it's not
3080	 * critical but the ftrace_call callers may be never nopped again after
3081	 * further ftrace uses.
3082	 */
3083	WARN_ON_ONCE(ftrace_start_up < 0);
3084
3085	/* Disabling ipmodify never fails */
3086	ftrace_hash_ipmodify_disable(ops);
3087
3088	if (ftrace_hash_rec_disable(ops, 1))
3089		command |= FTRACE_UPDATE_CALLS;
3090
3091	ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3092
3093	if (saved_ftrace_func != ftrace_trace_function) {
3094		saved_ftrace_func = ftrace_trace_function;
3095		command |= FTRACE_UPDATE_TRACE_FUNC;
3096	}
3097
3098	if (!command || !ftrace_enabled)
3099		goto out;
3100
3101	/*
3102	 * If the ops uses a trampoline, then it needs to be
3103	 * tested first on update.
3104	 */
3105	ops->flags |= FTRACE_OPS_FL_REMOVING;
3106	removed_ops = ops;
3107
3108	/* The trampoline logic checks the old hashes */
3109	ops->old_hash.filter_hash = ops->func_hash->filter_hash;
3110	ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
3111
3112	ftrace_run_update_code(command);
3113
3114	/*
3115	 * If there's no more ops registered with ftrace, run a
3116	 * sanity check to make sure all rec flags are cleared.
3117	 */
3118	if (rcu_dereference_protected(ftrace_ops_list,
3119			lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
3120		struct ftrace_page *pg;
3121		struct dyn_ftrace *rec;
3122
3123		do_for_each_ftrace_rec(pg, rec) {
3124			if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_NOCLEAR_FLAGS))
3125				pr_warn("  %pS flags:%lx\n",
3126					(void *)rec->ip, rec->flags);
3127		} while_for_each_ftrace_rec();
3128	}
3129
3130	ops->old_hash.filter_hash = NULL;
3131	ops->old_hash.notrace_hash = NULL;
3132
3133	removed_ops = NULL;
3134	ops->flags &= ~FTRACE_OPS_FL_REMOVING;
3135
3136out:
3137	/*
3138	 * Dynamic ops may be freed, we must make sure that all
3139	 * callers are done before leaving this function.
3140	 */
3141	if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
3142		/*
3143		 * We need to do a hard force of sched synchronization.
3144		 * This is because we use preempt_disable() to do RCU, but
3145		 * the function tracers can be called where RCU is not watching
3146		 * (like before user_exit()). We can not rely on the RCU
3147		 * infrastructure to do the synchronization, thus we must do it
3148		 * ourselves.
3149		 */
3150		synchronize_rcu_tasks_rude();
3151
3152		/*
3153		 * When the kernel is preemptive, tasks can be preempted
3154		 * while on a ftrace trampoline. Just scheduling a task on
3155		 * a CPU is not good enough to flush them. Calling
3156		 * synchronize_rcu_tasks() will wait for those tasks to
3157		 * execute and either schedule voluntarily or enter user space.
3158		 */
3159		if (IS_ENABLED(CONFIG_PREEMPTION))
3160			synchronize_rcu_tasks();
3161
3162		ftrace_trampoline_free(ops);
3163	}
3164
3165	return 0;
3166}
3167
3168static u64		ftrace_update_time;
3169unsigned long		ftrace_update_tot_cnt;
3170unsigned long		ftrace_number_of_pages;
3171unsigned long		ftrace_number_of_groups;
3172
3173static inline int ops_traces_mod(struct ftrace_ops *ops)
3174{
3175	/*
3176	 * Filter_hash being empty will default to trace module.
3177	 * But notrace hash requires a test of individual module functions.
3178	 */
3179	return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3180		ftrace_hash_empty(ops->func_hash->notrace_hash);
3181}
3182
3183static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3184{
3185	bool init_nop = ftrace_need_init_nop();
3186	struct ftrace_page *pg;
3187	struct dyn_ftrace *p;
3188	u64 start, stop;
3189	unsigned long update_cnt = 0;
3190	unsigned long rec_flags = 0;
3191	int i;
3192
3193	start = ftrace_now(raw_smp_processor_id());
3194
3195	/*
3196	 * When a module is loaded, this function is called to convert
3197	 * the calls to mcount in its text to nops, and also to create
3198	 * an entry in the ftrace data. Now, if ftrace is activated
3199	 * after this call, but before the module sets its text to
3200	 * read-only, the modification of enabling ftrace can fail if
3201	 * the read-only is done while ftrace is converting the calls.
3202	 * To prevent this, the module's records are set as disabled
3203	 * and will be enabled after the call to set the module's text
3204	 * to read-only.
3205	 */
3206	if (mod)
3207		rec_flags |= FTRACE_FL_DISABLED;
3208
3209	for (pg = new_pgs; pg; pg = pg->next) {
3210
3211		for (i = 0; i < pg->index; i++) {
3212
3213			/* If something went wrong, bail without enabling anything */
3214			if (unlikely(ftrace_disabled))
3215				return -1;
3216
3217			p = &pg->records[i];
3218			p->flags = rec_flags;
3219
3220			/*
3221			 * Do the initial record conversion from mcount jump
3222			 * to the NOP instructions.
3223			 */
3224			if (init_nop && !ftrace_nop_initialize(mod, p))
3225				break;
3226
3227			update_cnt++;
3228		}
3229	}
3230
3231	stop = ftrace_now(raw_smp_processor_id());
3232	ftrace_update_time = stop - start;
3233	ftrace_update_tot_cnt += update_cnt;
3234
3235	return 0;
3236}
3237
3238static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3239{
3240	int order;
3241	int pages;
3242	int cnt;
3243
3244	if (WARN_ON(!count))
3245		return -EINVAL;
3246
3247	/* We want to fill as much as possible, with no empty pages */
3248	pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3249	order = fls(pages) - 1;
3250
3251 again:
3252	pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3253
3254	if (!pg->records) {
3255		/* if we can't allocate this size, try something smaller */
3256		if (!order)
3257			return -ENOMEM;
3258		order--;
3259		goto again;
3260	}
3261
3262	ftrace_number_of_pages += 1 << order;
3263	ftrace_number_of_groups++;
3264
3265	cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3266	pg->order = order;
3267
3268	if (cnt > count)
3269		cnt = count;
3270
3271	return cnt;
3272}
3273
3274static void ftrace_free_pages(struct ftrace_page *pages)
3275{
3276	struct ftrace_page *pg = pages;
3277
3278	while (pg) {
3279		if (pg->records) {
3280			free_pages((unsigned long)pg->records, pg->order);
3281			ftrace_number_of_pages -= 1 << pg->order;
3282		}
3283		pages = pg->next;
3284		kfree(pg);
3285		pg = pages;
3286		ftrace_number_of_groups--;
3287	}
3288}
3289
3290static struct ftrace_page *
3291ftrace_allocate_pages(unsigned long num_to_init)
3292{
3293	struct ftrace_page *start_pg;
3294	struct ftrace_page *pg;
3295	int cnt;
3296
3297	if (!num_to_init)
3298		return NULL;
3299
3300	start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3301	if (!pg)
3302		return NULL;
3303
3304	/*
3305	 * Try to allocate as much as possible in one continues
3306	 * location that fills in all of the space. We want to
3307	 * waste as little space as possible.
3308	 */
3309	for (;;) {
3310		cnt = ftrace_allocate_records(pg, num_to_init);
3311		if (cnt < 0)
3312			goto free_pages;
3313
3314		num_to_init -= cnt;
3315		if (!num_to_init)
3316			break;
3317
3318		pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3319		if (!pg->next)
3320			goto free_pages;
3321
3322		pg = pg->next;
3323	}
3324
3325	return start_pg;
3326
3327 free_pages:
3328	ftrace_free_pages(start_pg);
 
 
 
 
 
 
 
 
 
 
3329	pr_info("ftrace: FAILED to allocate memory for functions\n");
3330	return NULL;
3331}
3332
3333#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3334
3335struct ftrace_iterator {
3336	loff_t				pos;
3337	loff_t				func_pos;
3338	loff_t				mod_pos;
3339	struct ftrace_page		*pg;
3340	struct dyn_ftrace		*func;
3341	struct ftrace_func_probe	*probe;
3342	struct ftrace_func_entry	*probe_entry;
3343	struct trace_parser		parser;
3344	struct ftrace_hash		*hash;
3345	struct ftrace_ops		*ops;
3346	struct trace_array		*tr;
3347	struct list_head		*mod_list;
3348	int				pidx;
3349	int				idx;
3350	unsigned			flags;
3351};
3352
3353static void *
3354t_probe_next(struct seq_file *m, loff_t *pos)
3355{
3356	struct ftrace_iterator *iter = m->private;
3357	struct trace_array *tr = iter->ops->private;
3358	struct list_head *func_probes;
3359	struct ftrace_hash *hash;
3360	struct list_head *next;
3361	struct hlist_node *hnd = NULL;
3362	struct hlist_head *hhd;
3363	int size;
3364
3365	(*pos)++;
3366	iter->pos = *pos;
3367
3368	if (!tr)
3369		return NULL;
3370
3371	func_probes = &tr->func_probes;
3372	if (list_empty(func_probes))
3373		return NULL;
3374
3375	if (!iter->probe) {
3376		next = func_probes->next;
3377		iter->probe = list_entry(next, struct ftrace_func_probe, list);
3378	}
3379
3380	if (iter->probe_entry)
3381		hnd = &iter->probe_entry->hlist;
3382
3383	hash = iter->probe->ops.func_hash->filter_hash;
3384
3385	/*
3386	 * A probe being registered may temporarily have an empty hash
3387	 * and it's at the end of the func_probes list.
3388	 */
3389	if (!hash || hash == EMPTY_HASH)
3390		return NULL;
3391
3392	size = 1 << hash->size_bits;
3393
3394 retry:
3395	if (iter->pidx >= size) {
3396		if (iter->probe->list.next == func_probes)
3397			return NULL;
3398		next = iter->probe->list.next;
3399		iter->probe = list_entry(next, struct ftrace_func_probe, list);
3400		hash = iter->probe->ops.func_hash->filter_hash;
3401		size = 1 << hash->size_bits;
3402		iter->pidx = 0;
3403	}
3404
3405	hhd = &hash->buckets[iter->pidx];
3406
3407	if (hlist_empty(hhd)) {
3408		iter->pidx++;
3409		hnd = NULL;
3410		goto retry;
3411	}
3412
3413	if (!hnd)
3414		hnd = hhd->first;
3415	else {
3416		hnd = hnd->next;
3417		if (!hnd) {
3418			iter->pidx++;
3419			goto retry;
3420		}
3421	}
3422
3423	if (WARN_ON_ONCE(!hnd))
3424		return NULL;
3425
3426	iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3427
3428	return iter;
3429}
3430
3431static void *t_probe_start(struct seq_file *m, loff_t *pos)
3432{
3433	struct ftrace_iterator *iter = m->private;
3434	void *p = NULL;
3435	loff_t l;
3436
3437	if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3438		return NULL;
3439
3440	if (iter->mod_pos > *pos)
3441		return NULL;
3442
3443	iter->probe = NULL;
3444	iter->probe_entry = NULL;
3445	iter->pidx = 0;
3446	for (l = 0; l <= (*pos - iter->mod_pos); ) {
3447		p = t_probe_next(m, &l);
3448		if (!p)
3449			break;
3450	}
3451	if (!p)
3452		return NULL;
3453
3454	/* Only set this if we have an item */
3455	iter->flags |= FTRACE_ITER_PROBE;
3456
3457	return iter;
3458}
3459
3460static int
3461t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3462{
3463	struct ftrace_func_entry *probe_entry;
3464	struct ftrace_probe_ops *probe_ops;
3465	struct ftrace_func_probe *probe;
3466
3467	probe = iter->probe;
3468	probe_entry = iter->probe_entry;
3469
3470	if (WARN_ON_ONCE(!probe || !probe_entry))
3471		return -EIO;
3472
3473	probe_ops = probe->probe_ops;
3474
3475	if (probe_ops->print)
3476		return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3477
3478	seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3479		   (void *)probe_ops->func);
3480
3481	return 0;
3482}
3483
3484static void *
3485t_mod_next(struct seq_file *m, loff_t *pos)
3486{
3487	struct ftrace_iterator *iter = m->private;
3488	struct trace_array *tr = iter->tr;
3489
3490	(*pos)++;
3491	iter->pos = *pos;
3492
3493	iter->mod_list = iter->mod_list->next;
3494
3495	if (iter->mod_list == &tr->mod_trace ||
3496	    iter->mod_list == &tr->mod_notrace) {
3497		iter->flags &= ~FTRACE_ITER_MOD;
3498		return NULL;
3499	}
3500
3501	iter->mod_pos = *pos;
3502
3503	return iter;
3504}
3505
3506static void *t_mod_start(struct seq_file *m, loff_t *pos)
3507{
3508	struct ftrace_iterator *iter = m->private;
3509	void *p = NULL;
3510	loff_t l;
3511
3512	if (iter->func_pos > *pos)
3513		return NULL;
3514
3515	iter->mod_pos = iter->func_pos;
3516
3517	/* probes are only available if tr is set */
3518	if (!iter->tr)
3519		return NULL;
3520
3521	for (l = 0; l <= (*pos - iter->func_pos); ) {
3522		p = t_mod_next(m, &l);
3523		if (!p)
3524			break;
3525	}
3526	if (!p) {
3527		iter->flags &= ~FTRACE_ITER_MOD;
3528		return t_probe_start(m, pos);
3529	}
3530
3531	/* Only set this if we have an item */
3532	iter->flags |= FTRACE_ITER_MOD;
3533
3534	return iter;
3535}
3536
3537static int
3538t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3539{
3540	struct ftrace_mod_load *ftrace_mod;
3541	struct trace_array *tr = iter->tr;
3542
3543	if (WARN_ON_ONCE(!iter->mod_list) ||
3544			 iter->mod_list == &tr->mod_trace ||
3545			 iter->mod_list == &tr->mod_notrace)
3546		return -EIO;
3547
3548	ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3549
3550	if (ftrace_mod->func)
3551		seq_printf(m, "%s", ftrace_mod->func);
3552	else
3553		seq_putc(m, '*');
3554
3555	seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3556
3557	return 0;
3558}
3559
3560static void *
3561t_func_next(struct seq_file *m, loff_t *pos)
3562{
3563	struct ftrace_iterator *iter = m->private;
3564	struct dyn_ftrace *rec = NULL;
3565
3566	(*pos)++;
3567
3568 retry:
3569	if (iter->idx >= iter->pg->index) {
3570		if (iter->pg->next) {
3571			iter->pg = iter->pg->next;
3572			iter->idx = 0;
3573			goto retry;
3574		}
3575	} else {
3576		rec = &iter->pg->records[iter->idx++];
3577		if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3578		     !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3579
3580		    ((iter->flags & FTRACE_ITER_ENABLED) &&
3581		     !(rec->flags & FTRACE_FL_ENABLED)) ||
3582
3583		    ((iter->flags & FTRACE_ITER_TOUCHED) &&
3584		     !(rec->flags & FTRACE_FL_TOUCHED))) {
3585
3586			rec = NULL;
3587			goto retry;
3588		}
3589	}
3590
3591	if (!rec)
3592		return NULL;
3593
3594	iter->pos = iter->func_pos = *pos;
3595	iter->func = rec;
3596
3597	return iter;
3598}
3599
3600static void *
3601t_next(struct seq_file *m, void *v, loff_t *pos)
3602{
3603	struct ftrace_iterator *iter = m->private;
3604	loff_t l = *pos; /* t_probe_start() must use original pos */
3605	void *ret;
3606
3607	if (unlikely(ftrace_disabled))
3608		return NULL;
3609
3610	if (iter->flags & FTRACE_ITER_PROBE)
3611		return t_probe_next(m, pos);
3612
3613	if (iter->flags & FTRACE_ITER_MOD)
3614		return t_mod_next(m, pos);
3615
3616	if (iter->flags & FTRACE_ITER_PRINTALL) {
3617		/* next must increment pos, and t_probe_start does not */
3618		(*pos)++;
3619		return t_mod_start(m, &l);
3620	}
3621
3622	ret = t_func_next(m, pos);
3623
3624	if (!ret)
3625		return t_mod_start(m, &l);
3626
3627	return ret;
3628}
3629
3630static void reset_iter_read(struct ftrace_iterator *iter)
3631{
3632	iter->pos = 0;
3633	iter->func_pos = 0;
3634	iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3635}
3636
3637static void *t_start(struct seq_file *m, loff_t *pos)
3638{
3639	struct ftrace_iterator *iter = m->private;
3640	void *p = NULL;
3641	loff_t l;
3642
3643	mutex_lock(&ftrace_lock);
3644
3645	if (unlikely(ftrace_disabled))
3646		return NULL;
3647
3648	/*
3649	 * If an lseek was done, then reset and start from beginning.
3650	 */
3651	if (*pos < iter->pos)
3652		reset_iter_read(iter);
3653
3654	/*
3655	 * For set_ftrace_filter reading, if we have the filter
3656	 * off, we can short cut and just print out that all
3657	 * functions are enabled.
3658	 */
3659	if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3660	    ftrace_hash_empty(iter->hash)) {
3661		iter->func_pos = 1; /* Account for the message */
3662		if (*pos > 0)
3663			return t_mod_start(m, pos);
3664		iter->flags |= FTRACE_ITER_PRINTALL;
3665		/* reset in case of seek/pread */
3666		iter->flags &= ~FTRACE_ITER_PROBE;
3667		return iter;
3668	}
3669
3670	if (iter->flags & FTRACE_ITER_MOD)
3671		return t_mod_start(m, pos);
3672
3673	/*
3674	 * Unfortunately, we need to restart at ftrace_pages_start
3675	 * every time we let go of the ftrace_mutex. This is because
3676	 * those pointers can change without the lock.
3677	 */
3678	iter->pg = ftrace_pages_start;
3679	iter->idx = 0;
3680	for (l = 0; l <= *pos; ) {
3681		p = t_func_next(m, &l);
3682		if (!p)
3683			break;
3684	}
3685
3686	if (!p)
3687		return t_mod_start(m, pos);
3688
3689	return iter;
3690}
3691
3692static void t_stop(struct seq_file *m, void *p)
3693{
3694	mutex_unlock(&ftrace_lock);
3695}
3696
3697void * __weak
3698arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3699{
3700	return NULL;
3701}
3702
3703static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3704				struct dyn_ftrace *rec)
3705{
3706	void *ptr;
3707
3708	ptr = arch_ftrace_trampoline_func(ops, rec);
3709	if (ptr)
3710		seq_printf(m, " ->%pS", ptr);
3711}
3712
3713#ifdef FTRACE_MCOUNT_MAX_OFFSET
3714/*
3715 * Weak functions can still have an mcount/fentry that is saved in
3716 * the __mcount_loc section. These can be detected by having a
3717 * symbol offset of greater than FTRACE_MCOUNT_MAX_OFFSET, as the
3718 * symbol found by kallsyms is not the function that the mcount/fentry
3719 * is part of. The offset is much greater in these cases.
3720 *
3721 * Test the record to make sure that the ip points to a valid kallsyms
3722 * and if not, mark it disabled.
3723 */
3724static int test_for_valid_rec(struct dyn_ftrace *rec)
3725{
3726	char str[KSYM_SYMBOL_LEN];
3727	unsigned long offset;
3728	const char *ret;
3729
3730	ret = kallsyms_lookup(rec->ip, NULL, &offset, NULL, str);
3731
3732	/* Weak functions can cause invalid addresses */
3733	if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3734		rec->flags |= FTRACE_FL_DISABLED;
3735		return 0;
3736	}
3737	return 1;
3738}
3739
3740static struct workqueue_struct *ftrace_check_wq __initdata;
3741static struct work_struct ftrace_check_work __initdata;
3742
3743/*
3744 * Scan all the mcount/fentry entries to make sure they are valid.
3745 */
3746static __init void ftrace_check_work_func(struct work_struct *work)
3747{
3748	struct ftrace_page *pg;
3749	struct dyn_ftrace *rec;
3750
3751	mutex_lock(&ftrace_lock);
3752	do_for_each_ftrace_rec(pg, rec) {
3753		test_for_valid_rec(rec);
3754	} while_for_each_ftrace_rec();
3755	mutex_unlock(&ftrace_lock);
3756}
3757
3758static int __init ftrace_check_for_weak_functions(void)
3759{
3760	INIT_WORK(&ftrace_check_work, ftrace_check_work_func);
3761
3762	ftrace_check_wq = alloc_workqueue("ftrace_check_wq", WQ_UNBOUND, 0);
3763
3764	queue_work(ftrace_check_wq, &ftrace_check_work);
3765	return 0;
3766}
3767
3768static int __init ftrace_check_sync(void)
3769{
3770	/* Make sure the ftrace_check updates are finished */
3771	if (ftrace_check_wq)
3772		destroy_workqueue(ftrace_check_wq);
3773	return 0;
3774}
3775
3776late_initcall_sync(ftrace_check_sync);
3777subsys_initcall(ftrace_check_for_weak_functions);
3778
3779static int print_rec(struct seq_file *m, unsigned long ip)
3780{
3781	unsigned long offset;
3782	char str[KSYM_SYMBOL_LEN];
3783	char *modname;
3784	const char *ret;
3785
3786	ret = kallsyms_lookup(ip, NULL, &offset, &modname, str);
3787	/* Weak functions can cause invalid addresses */
3788	if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3789		snprintf(str, KSYM_SYMBOL_LEN, "%s_%ld",
3790			 FTRACE_INVALID_FUNCTION, offset);
3791		ret = NULL;
3792	}
3793
3794	seq_puts(m, str);
3795	if (modname)
3796		seq_printf(m, " [%s]", modname);
3797	return ret == NULL ? -1 : 0;
3798}
3799#else
3800static inline int test_for_valid_rec(struct dyn_ftrace *rec)
3801{
3802	return 1;
3803}
3804
3805static inline int print_rec(struct seq_file *m, unsigned long ip)
3806{
3807	seq_printf(m, "%ps", (void *)ip);
3808	return 0;
3809}
3810#endif
3811
3812static int t_show(struct seq_file *m, void *v)
3813{
3814	struct ftrace_iterator *iter = m->private;
3815	struct dyn_ftrace *rec;
3816
3817	if (iter->flags & FTRACE_ITER_PROBE)
3818		return t_probe_show(m, iter);
3819
3820	if (iter->flags & FTRACE_ITER_MOD)
3821		return t_mod_show(m, iter);
3822
3823	if (iter->flags & FTRACE_ITER_PRINTALL) {
3824		if (iter->flags & FTRACE_ITER_NOTRACE)
3825			seq_puts(m, "#### no functions disabled ####\n");
3826		else
3827			seq_puts(m, "#### all functions enabled ####\n");
3828		return 0;
3829	}
3830
3831	rec = iter->func;
3832
3833	if (!rec)
3834		return 0;
3835
3836	if (iter->flags & FTRACE_ITER_ADDRS)
3837		seq_printf(m, "%lx ", rec->ip);
3838
3839	if (print_rec(m, rec->ip)) {
3840		/* This should only happen when a rec is disabled */
3841		WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
3842		seq_putc(m, '\n');
3843		return 0;
3844	}
3845
3846	if (iter->flags & (FTRACE_ITER_ENABLED | FTRACE_ITER_TOUCHED)) {
3847		struct ftrace_ops *ops;
3848
3849		seq_printf(m, " (%ld)%s%s%s%s%s",
3850			   ftrace_rec_count(rec),
3851			   rec->flags & FTRACE_FL_REGS ? " R" : "  ",
3852			   rec->flags & FTRACE_FL_IPMODIFY ? " I" : "  ",
3853			   rec->flags & FTRACE_FL_DIRECT ? " D" : "  ",
3854			   rec->flags & FTRACE_FL_CALL_OPS ? " O" : "  ",
3855			   rec->flags & FTRACE_FL_MODIFIED ? " M " : "   ");
3856		if (rec->flags & FTRACE_FL_TRAMP_EN) {
3857			ops = ftrace_find_tramp_ops_any(rec);
3858			if (ops) {
3859				do {
3860					seq_printf(m, "\ttramp: %pS (%pS)",
3861						   (void *)ops->trampoline,
3862						   (void *)ops->func);
3863					add_trampoline_func(m, ops, rec);
3864					ops = ftrace_find_tramp_ops_next(rec, ops);
3865				} while (ops);
3866			} else
3867				seq_puts(m, "\ttramp: ERROR!");
3868		} else {
3869			add_trampoline_func(m, NULL, rec);
3870		}
3871		if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
3872			ops = ftrace_find_unique_ops(rec);
3873			if (ops) {
3874				seq_printf(m, "\tops: %pS (%pS)",
3875					   ops, ops->func);
3876			} else {
3877				seq_puts(m, "\tops: ERROR!");
3878			}
3879		}
3880		if (rec->flags & FTRACE_FL_DIRECT) {
3881			unsigned long direct;
3882
3883			direct = ftrace_find_rec_direct(rec->ip);
3884			if (direct)
3885				seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3886		}
3887	}
3888
3889	seq_putc(m, '\n');
3890
3891	return 0;
3892}
3893
3894static const struct seq_operations show_ftrace_seq_ops = {
3895	.start = t_start,
3896	.next = t_next,
3897	.stop = t_stop,
3898	.show = t_show,
3899};
3900
3901static int
3902ftrace_avail_open(struct inode *inode, struct file *file)
3903{
3904	struct ftrace_iterator *iter;
3905	int ret;
3906
3907	ret = security_locked_down(LOCKDOWN_TRACEFS);
3908	if (ret)
3909		return ret;
3910
3911	if (unlikely(ftrace_disabled))
3912		return -ENODEV;
3913
3914	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3915	if (!iter)
3916		return -ENOMEM;
3917
3918	iter->pg = ftrace_pages_start;
3919	iter->ops = &global_ops;
3920
3921	return 0;
3922}
3923
3924static int
3925ftrace_enabled_open(struct inode *inode, struct file *file)
3926{
3927	struct ftrace_iterator *iter;
3928
3929	/*
3930	 * This shows us what functions are currently being
3931	 * traced and by what. Not sure if we want lockdown
3932	 * to hide such critical information for an admin.
3933	 * Although, perhaps it can show information we don't
3934	 * want people to see, but if something is tracing
3935	 * something, we probably want to know about it.
3936	 */
3937
3938	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3939	if (!iter)
3940		return -ENOMEM;
3941
3942	iter->pg = ftrace_pages_start;
3943	iter->flags = FTRACE_ITER_ENABLED;
3944	iter->ops = &global_ops;
3945
3946	return 0;
3947}
3948
3949static int
3950ftrace_touched_open(struct inode *inode, struct file *file)
3951{
3952	struct ftrace_iterator *iter;
3953
3954	/*
3955	 * This shows us what functions have ever been enabled
3956	 * (traced, direct, patched, etc). Not sure if we want lockdown
3957	 * to hide such critical information for an admin.
3958	 * Although, perhaps it can show information we don't
3959	 * want people to see, but if something had traced
3960	 * something, we probably want to know about it.
3961	 */
3962
3963	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3964	if (!iter)
3965		return -ENOMEM;
3966
3967	iter->pg = ftrace_pages_start;
3968	iter->flags = FTRACE_ITER_TOUCHED;
3969	iter->ops = &global_ops;
3970
3971	return 0;
3972}
3973
3974static int
3975ftrace_avail_addrs_open(struct inode *inode, struct file *file)
3976{
3977	struct ftrace_iterator *iter;
3978	int ret;
3979
3980	ret = security_locked_down(LOCKDOWN_TRACEFS);
3981	if (ret)
3982		return ret;
3983
3984	if (unlikely(ftrace_disabled))
3985		return -ENODEV;
3986
3987	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3988	if (!iter)
3989		return -ENOMEM;
3990
3991	iter->pg = ftrace_pages_start;
3992	iter->flags = FTRACE_ITER_ADDRS;
3993	iter->ops = &global_ops;
3994
3995	return 0;
3996}
3997
3998/**
3999 * ftrace_regex_open - initialize function tracer filter files
4000 * @ops: The ftrace_ops that hold the hash filters
4001 * @flag: The type of filter to process
4002 * @inode: The inode, usually passed in to your open routine
4003 * @file: The file, usually passed in to your open routine
4004 *
4005 * ftrace_regex_open() initializes the filter files for the
4006 * @ops. Depending on @flag it may process the filter hash or
4007 * the notrace hash of @ops. With this called from the open
4008 * routine, you can use ftrace_filter_write() for the write
4009 * routine if @flag has FTRACE_ITER_FILTER set, or
4010 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
4011 * tracing_lseek() should be used as the lseek routine, and
4012 * release must call ftrace_regex_release().
4013 */
4014int
4015ftrace_regex_open(struct ftrace_ops *ops, int flag,
4016		  struct inode *inode, struct file *file)
4017{
4018	struct ftrace_iterator *iter;
4019	struct ftrace_hash *hash;
4020	struct list_head *mod_head;
4021	struct trace_array *tr = ops->private;
4022	int ret = -ENOMEM;
4023
4024	ftrace_ops_init(ops);
4025
4026	if (unlikely(ftrace_disabled))
4027		return -ENODEV;
4028
4029	if (tracing_check_open_get_tr(tr))
4030		return -ENODEV;
4031
4032	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
4033	if (!iter)
4034		goto out;
4035
4036	if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
4037		goto out;
4038
4039	iter->ops = ops;
4040	iter->flags = flag;
4041	iter->tr = tr;
4042
4043	mutex_lock(&ops->func_hash->regex_lock);
4044
4045	if (flag & FTRACE_ITER_NOTRACE) {
4046		hash = ops->func_hash->notrace_hash;
4047		mod_head = tr ? &tr->mod_notrace : NULL;
4048	} else {
4049		hash = ops->func_hash->filter_hash;
4050		mod_head = tr ? &tr->mod_trace : NULL;
4051	}
4052
4053	iter->mod_list = mod_head;
4054
4055	if (file->f_mode & FMODE_WRITE) {
4056		const int size_bits = FTRACE_HASH_DEFAULT_BITS;
4057
4058		if (file->f_flags & O_TRUNC) {
4059			iter->hash = alloc_ftrace_hash(size_bits);
4060			clear_ftrace_mod_list(mod_head);
4061	        } else {
4062			iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
4063		}
4064
4065		if (!iter->hash) {
4066			trace_parser_put(&iter->parser);
4067			goto out_unlock;
4068		}
4069	} else
4070		iter->hash = hash;
4071
4072	ret = 0;
4073
4074	if (file->f_mode & FMODE_READ) {
4075		iter->pg = ftrace_pages_start;
4076
4077		ret = seq_open(file, &show_ftrace_seq_ops);
4078		if (!ret) {
4079			struct seq_file *m = file->private_data;
4080			m->private = iter;
4081		} else {
4082			/* Failed */
4083			free_ftrace_hash(iter->hash);
4084			trace_parser_put(&iter->parser);
4085		}
4086	} else
4087		file->private_data = iter;
4088
4089 out_unlock:
4090	mutex_unlock(&ops->func_hash->regex_lock);
4091
4092 out:
4093	if (ret) {
4094		kfree(iter);
4095		if (tr)
4096			trace_array_put(tr);
4097	}
4098
4099	return ret;
4100}
4101
4102static int
4103ftrace_filter_open(struct inode *inode, struct file *file)
4104{
4105	struct ftrace_ops *ops = inode->i_private;
4106
4107	/* Checks for tracefs lockdown */
4108	return ftrace_regex_open(ops,
4109			FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
4110			inode, file);
4111}
4112
4113static int
4114ftrace_notrace_open(struct inode *inode, struct file *file)
4115{
4116	struct ftrace_ops *ops = inode->i_private;
4117
4118	/* Checks for tracefs lockdown */
4119	return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
4120				 inode, file);
4121}
4122
4123/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
4124struct ftrace_glob {
4125	char *search;
4126	unsigned len;
4127	int type;
4128};
4129
4130/*
4131 * If symbols in an architecture don't correspond exactly to the user-visible
4132 * name of what they represent, it is possible to define this function to
4133 * perform the necessary adjustments.
4134*/
4135char * __weak arch_ftrace_match_adjust(char *str, const char *search)
4136{
4137	return str;
4138}
4139
4140static int ftrace_match(char *str, struct ftrace_glob *g)
4141{
4142	int matched = 0;
4143	int slen;
4144
4145	str = arch_ftrace_match_adjust(str, g->search);
4146
4147	switch (g->type) {
4148	case MATCH_FULL:
4149		if (strcmp(str, g->search) == 0)
4150			matched = 1;
4151		break;
4152	case MATCH_FRONT_ONLY:
4153		if (strncmp(str, g->search, g->len) == 0)
4154			matched = 1;
4155		break;
4156	case MATCH_MIDDLE_ONLY:
4157		if (strstr(str, g->search))
4158			matched = 1;
4159		break;
4160	case MATCH_END_ONLY:
4161		slen = strlen(str);
4162		if (slen >= g->len &&
4163		    memcmp(str + slen - g->len, g->search, g->len) == 0)
4164			matched = 1;
4165		break;
4166	case MATCH_GLOB:
4167		if (glob_match(g->search, str))
4168			matched = 1;
4169		break;
4170	}
4171
4172	return matched;
4173}
4174
4175static int
4176enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
4177{
4178	struct ftrace_func_entry *entry;
4179	int ret = 0;
4180
4181	entry = ftrace_lookup_ip(hash, rec->ip);
4182	if (clear_filter) {
4183		/* Do nothing if it doesn't exist */
4184		if (!entry)
4185			return 0;
4186
4187		free_hash_entry(hash, entry);
4188	} else {
4189		/* Do nothing if it exists */
4190		if (entry)
4191			return 0;
4192		if (add_hash_entry(hash, rec->ip) == NULL)
4193			ret = -ENOMEM;
4194	}
4195	return ret;
4196}
4197
4198static int
4199add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
4200		 int clear_filter)
4201{
4202	long index = simple_strtoul(func_g->search, NULL, 0);
4203	struct ftrace_page *pg;
4204	struct dyn_ftrace *rec;
4205
4206	/* The index starts at 1 */
4207	if (--index < 0)
4208		return 0;
4209
4210	do_for_each_ftrace_rec(pg, rec) {
4211		if (pg->index <= index) {
4212			index -= pg->index;
4213			/* this is a double loop, break goes to the next page */
4214			break;
4215		}
4216		rec = &pg->records[index];
4217		enter_record(hash, rec, clear_filter);
4218		return 1;
4219	} while_for_each_ftrace_rec();
4220	return 0;
4221}
4222
4223#ifdef FTRACE_MCOUNT_MAX_OFFSET
4224static int lookup_ip(unsigned long ip, char **modname, char *str)
4225{
4226	unsigned long offset;
4227
4228	kallsyms_lookup(ip, NULL, &offset, modname, str);
4229	if (offset > FTRACE_MCOUNT_MAX_OFFSET)
4230		return -1;
4231	return 0;
4232}
4233#else
4234static int lookup_ip(unsigned long ip, char **modname, char *str)
4235{
4236	kallsyms_lookup(ip, NULL, NULL, modname, str);
4237	return 0;
4238}
4239#endif
4240
4241static int
4242ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
4243		struct ftrace_glob *mod_g, int exclude_mod)
4244{
4245	char str[KSYM_SYMBOL_LEN];
4246	char *modname;
4247
4248	if (lookup_ip(rec->ip, &modname, str)) {
4249		/* This should only happen when a rec is disabled */
4250		WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
4251			     !(rec->flags & FTRACE_FL_DISABLED));
4252		return 0;
4253	}
4254
4255	if (mod_g) {
4256		int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
4257
4258		/* blank module name to match all modules */
4259		if (!mod_g->len) {
4260			/* blank module globbing: modname xor exclude_mod */
4261			if (!exclude_mod != !modname)
4262				goto func_match;
4263			return 0;
4264		}
4265
4266		/*
4267		 * exclude_mod is set to trace everything but the given
4268		 * module. If it is set and the module matches, then
4269		 * return 0. If it is not set, and the module doesn't match
4270		 * also return 0. Otherwise, check the function to see if
4271		 * that matches.
4272		 */
4273		if (!mod_matches == !exclude_mod)
4274			return 0;
4275func_match:
4276		/* blank search means to match all funcs in the mod */
4277		if (!func_g->len)
4278			return 1;
4279	}
4280
4281	return ftrace_match(str, func_g);
4282}
4283
4284static int
4285match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4286{
4287	struct ftrace_page *pg;
4288	struct dyn_ftrace *rec;
4289	struct ftrace_glob func_g = { .type = MATCH_FULL };
4290	struct ftrace_glob mod_g = { .type = MATCH_FULL };
4291	struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4292	int exclude_mod = 0;
4293	int found = 0;
4294	int ret;
4295	int clear_filter = 0;
4296
4297	if (func) {
4298		func_g.type = filter_parse_regex(func, len, &func_g.search,
4299						 &clear_filter);
4300		func_g.len = strlen(func_g.search);
4301	}
4302
4303	if (mod) {
4304		mod_g.type = filter_parse_regex(mod, strlen(mod),
4305				&mod_g.search, &exclude_mod);
4306		mod_g.len = strlen(mod_g.search);
4307	}
4308
4309	mutex_lock(&ftrace_lock);
4310
4311	if (unlikely(ftrace_disabled))
4312		goto out_unlock;
4313
4314	if (func_g.type == MATCH_INDEX) {
4315		found = add_rec_by_index(hash, &func_g, clear_filter);
4316		goto out_unlock;
4317	}
4318
4319	do_for_each_ftrace_rec(pg, rec) {
4320
4321		if (rec->flags & FTRACE_FL_DISABLED)
4322			continue;
4323
4324		if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4325			ret = enter_record(hash, rec, clear_filter);
4326			if (ret < 0) {
4327				found = ret;
4328				goto out_unlock;
4329			}
4330			found = 1;
4331		}
4332		cond_resched();
4333	} while_for_each_ftrace_rec();
4334 out_unlock:
4335	mutex_unlock(&ftrace_lock);
4336
4337	return found;
4338}
4339
4340static int
4341ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4342{
4343	return match_records(hash, buff, len, NULL);
4344}
4345
4346static void ftrace_ops_update_code(struct ftrace_ops *ops,
4347				   struct ftrace_ops_hash *old_hash)
4348{
4349	struct ftrace_ops *op;
4350
4351	if (!ftrace_enabled)
4352		return;
4353
4354	if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4355		ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4356		return;
4357	}
4358
4359	/*
4360	 * If this is the shared global_ops filter, then we need to
4361	 * check if there is another ops that shares it, is enabled.
4362	 * If so, we still need to run the modify code.
4363	 */
4364	if (ops->func_hash != &global_ops.local_hash)
4365		return;
4366
4367	do_for_each_ftrace_op(op, ftrace_ops_list) {
4368		if (op->func_hash == &global_ops.local_hash &&
4369		    op->flags & FTRACE_OPS_FL_ENABLED) {
4370			ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4371			/* Only need to do this once */
4372			return;
4373		}
4374	} while_for_each_ftrace_op(op);
4375}
4376
4377static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4378					   struct ftrace_hash **orig_hash,
4379					   struct ftrace_hash *hash,
4380					   int enable)
4381{
4382	struct ftrace_ops_hash old_hash_ops;
4383	struct ftrace_hash *old_hash;
4384	int ret;
4385
4386	old_hash = *orig_hash;
4387	old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4388	old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4389	ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4390	if (!ret) {
4391		ftrace_ops_update_code(ops, &old_hash_ops);
4392		free_ftrace_hash_rcu(old_hash);
4393	}
4394	return ret;
4395}
4396
4397static bool module_exists(const char *module)
4398{
4399	/* All modules have the symbol __this_module */
4400	static const char this_mod[] = "__this_module";
4401	char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4402	unsigned long val;
4403	int n;
4404
4405	n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4406
4407	if (n > sizeof(modname) - 1)
4408		return false;
4409
4410	val = module_kallsyms_lookup_name(modname);
4411	return val != 0;
4412}
4413
4414static int cache_mod(struct trace_array *tr,
4415		     const char *func, char *module, int enable)
4416{
4417	struct ftrace_mod_load *ftrace_mod, *n;
4418	struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4419	int ret;
4420
4421	mutex_lock(&ftrace_lock);
4422
4423	/* We do not cache inverse filters */
4424	if (func[0] == '!') {
4425		func++;
4426		ret = -EINVAL;
4427
4428		/* Look to remove this hash */
4429		list_for_each_entry_safe(ftrace_mod, n, head, list) {
4430			if (strcmp(ftrace_mod->module, module) != 0)
4431				continue;
4432
4433			/* no func matches all */
4434			if (strcmp(func, "*") == 0 ||
4435			    (ftrace_mod->func &&
4436			     strcmp(ftrace_mod->func, func) == 0)) {
4437				ret = 0;
4438				free_ftrace_mod(ftrace_mod);
4439				continue;
4440			}
4441		}
4442		goto out;
4443	}
4444
4445	ret = -EINVAL;
4446	/* We only care about modules that have not been loaded yet */
4447	if (module_exists(module))
4448		goto out;
4449
4450	/* Save this string off, and execute it when the module is loaded */
4451	ret = ftrace_add_mod(tr, func, module, enable);
4452 out:
4453	mutex_unlock(&ftrace_lock);
4454
4455	return ret;
4456}
4457
4458static int
4459ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4460		 int reset, int enable);
4461
4462#ifdef CONFIG_MODULES
4463static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4464			     char *mod, bool enable)
4465{
4466	struct ftrace_mod_load *ftrace_mod, *n;
4467	struct ftrace_hash **orig_hash, *new_hash;
4468	LIST_HEAD(process_mods);
4469	char *func;
4470
4471	mutex_lock(&ops->func_hash->regex_lock);
4472
4473	if (enable)
4474		orig_hash = &ops->func_hash->filter_hash;
4475	else
4476		orig_hash = &ops->func_hash->notrace_hash;
4477
4478	new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4479					      *orig_hash);
4480	if (!new_hash)
4481		goto out; /* warn? */
4482
4483	mutex_lock(&ftrace_lock);
4484
4485	list_for_each_entry_safe(ftrace_mod, n, head, list) {
4486
4487		if (strcmp(ftrace_mod->module, mod) != 0)
4488			continue;
4489
4490		if (ftrace_mod->func)
4491			func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4492		else
4493			func = kstrdup("*", GFP_KERNEL);
4494
4495		if (!func) /* warn? */
4496			continue;
4497
4498		list_move(&ftrace_mod->list, &process_mods);
4499
4500		/* Use the newly allocated func, as it may be "*" */
4501		kfree(ftrace_mod->func);
4502		ftrace_mod->func = func;
4503	}
4504
4505	mutex_unlock(&ftrace_lock);
4506
4507	list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4508
4509		func = ftrace_mod->func;
4510
4511		/* Grabs ftrace_lock, which is why we have this extra step */
4512		match_records(new_hash, func, strlen(func), mod);
4513		free_ftrace_mod(ftrace_mod);
4514	}
4515
4516	if (enable && list_empty(head))
4517		new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4518
4519	mutex_lock(&ftrace_lock);
4520
4521	ftrace_hash_move_and_update_ops(ops, orig_hash,
4522					      new_hash, enable);
4523	mutex_unlock(&ftrace_lock);
4524
4525 out:
4526	mutex_unlock(&ops->func_hash->regex_lock);
4527
4528	free_ftrace_hash(new_hash);
4529}
4530
4531static void process_cached_mods(const char *mod_name)
4532{
4533	struct trace_array *tr;
4534	char *mod;
4535
4536	mod = kstrdup(mod_name, GFP_KERNEL);
4537	if (!mod)
4538		return;
4539
4540	mutex_lock(&trace_types_lock);
4541	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4542		if (!list_empty(&tr->mod_trace))
4543			process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4544		if (!list_empty(&tr->mod_notrace))
4545			process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4546	}
4547	mutex_unlock(&trace_types_lock);
4548
4549	kfree(mod);
4550}
4551#endif
4552
4553/*
4554 * We register the module command as a template to show others how
4555 * to register the a command as well.
4556 */
4557
4558static int
4559ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4560		    char *func_orig, char *cmd, char *module, int enable)
4561{
4562	char *func;
4563	int ret;
4564
4565	/* match_records() modifies func, and we need the original */
4566	func = kstrdup(func_orig, GFP_KERNEL);
4567	if (!func)
4568		return -ENOMEM;
4569
4570	/*
4571	 * cmd == 'mod' because we only registered this func
4572	 * for the 'mod' ftrace_func_command.
4573	 * But if you register one func with multiple commands,
4574	 * you can tell which command was used by the cmd
4575	 * parameter.
4576	 */
4577	ret = match_records(hash, func, strlen(func), module);
4578	kfree(func);
4579
4580	if (!ret)
4581		return cache_mod(tr, func_orig, module, enable);
4582	if (ret < 0)
4583		return ret;
4584	return 0;
4585}
4586
4587static struct ftrace_func_command ftrace_mod_cmd = {
4588	.name			= "mod",
4589	.func			= ftrace_mod_callback,
4590};
4591
4592static int __init ftrace_mod_cmd_init(void)
4593{
4594	return register_ftrace_command(&ftrace_mod_cmd);
4595}
4596core_initcall(ftrace_mod_cmd_init);
4597
4598static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4599				      struct ftrace_ops *op, struct ftrace_regs *fregs)
4600{
4601	struct ftrace_probe_ops *probe_ops;
4602	struct ftrace_func_probe *probe;
4603
4604	probe = container_of(op, struct ftrace_func_probe, ops);
4605	probe_ops = probe->probe_ops;
4606
4607	/*
4608	 * Disable preemption for these calls to prevent a RCU grace
4609	 * period. This syncs the hash iteration and freeing of items
4610	 * on the hash. rcu_read_lock is too dangerous here.
4611	 */
4612	preempt_disable_notrace();
4613	probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4614	preempt_enable_notrace();
4615}
4616
4617struct ftrace_func_map {
4618	struct ftrace_func_entry	entry;
4619	void				*data;
4620};
4621
4622struct ftrace_func_mapper {
4623	struct ftrace_hash		hash;
4624};
4625
4626/**
4627 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4628 *
4629 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4630 */
4631struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4632{
4633	struct ftrace_hash *hash;
4634
4635	/*
4636	 * The mapper is simply a ftrace_hash, but since the entries
4637	 * in the hash are not ftrace_func_entry type, we define it
4638	 * as a separate structure.
4639	 */
4640	hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4641	return (struct ftrace_func_mapper *)hash;
4642}
4643
4644/**
4645 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4646 * @mapper: The mapper that has the ip maps
4647 * @ip: the instruction pointer to find the data for
4648 *
4649 * Returns the data mapped to @ip if found otherwise NULL. The return
4650 * is actually the address of the mapper data pointer. The address is
4651 * returned for use cases where the data is no bigger than a long, and
4652 * the user can use the data pointer as its data instead of having to
4653 * allocate more memory for the reference.
4654 */
4655void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4656				  unsigned long ip)
4657{
4658	struct ftrace_func_entry *entry;
4659	struct ftrace_func_map *map;
4660
4661	entry = ftrace_lookup_ip(&mapper->hash, ip);
4662	if (!entry)
4663		return NULL;
4664
4665	map = (struct ftrace_func_map *)entry;
4666	return &map->data;
4667}
4668
4669/**
4670 * ftrace_func_mapper_add_ip - Map some data to an ip
4671 * @mapper: The mapper that has the ip maps
4672 * @ip: The instruction pointer address to map @data to
4673 * @data: The data to map to @ip
4674 *
4675 * Returns 0 on success otherwise an error.
4676 */
4677int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4678			      unsigned long ip, void *data)
4679{
4680	struct ftrace_func_entry *entry;
4681	struct ftrace_func_map *map;
4682
4683	entry = ftrace_lookup_ip(&mapper->hash, ip);
4684	if (entry)
4685		return -EBUSY;
4686
4687	map = kmalloc(sizeof(*map), GFP_KERNEL);
4688	if (!map)
4689		return -ENOMEM;
4690
4691	map->entry.ip = ip;
4692	map->data = data;
4693
4694	__add_hash_entry(&mapper->hash, &map->entry);
4695
4696	return 0;
4697}
4698
4699/**
4700 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4701 * @mapper: The mapper that has the ip maps
4702 * @ip: The instruction pointer address to remove the data from
4703 *
4704 * Returns the data if it is found, otherwise NULL.
4705 * Note, if the data pointer is used as the data itself, (see
4706 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4707 * if the data pointer was set to zero.
4708 */
4709void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4710				   unsigned long ip)
4711{
4712	struct ftrace_func_entry *entry;
4713	struct ftrace_func_map *map;
4714	void *data;
4715
4716	entry = ftrace_lookup_ip(&mapper->hash, ip);
4717	if (!entry)
4718		return NULL;
4719
4720	map = (struct ftrace_func_map *)entry;
4721	data = map->data;
4722
4723	remove_hash_entry(&mapper->hash, entry);
4724	kfree(entry);
4725
4726	return data;
4727}
4728
4729/**
4730 * free_ftrace_func_mapper - free a mapping of ips and data
4731 * @mapper: The mapper that has the ip maps
4732 * @free_func: A function to be called on each data item.
4733 *
4734 * This is used to free the function mapper. The @free_func is optional
4735 * and can be used if the data needs to be freed as well.
4736 */
4737void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4738			     ftrace_mapper_func free_func)
4739{
4740	struct ftrace_func_entry *entry;
4741	struct ftrace_func_map *map;
4742	struct hlist_head *hhd;
4743	int size, i;
4744
4745	if (!mapper)
4746		return;
4747
4748	if (free_func && mapper->hash.count) {
4749		size = 1 << mapper->hash.size_bits;
4750		for (i = 0; i < size; i++) {
4751			hhd = &mapper->hash.buckets[i];
4752			hlist_for_each_entry(entry, hhd, hlist) {
4753				map = (struct ftrace_func_map *)entry;
4754				free_func(map);
4755			}
4756		}
4757	}
4758	free_ftrace_hash(&mapper->hash);
4759}
4760
4761static void release_probe(struct ftrace_func_probe *probe)
4762{
4763	struct ftrace_probe_ops *probe_ops;
4764
4765	mutex_lock(&ftrace_lock);
4766
4767	WARN_ON(probe->ref <= 0);
4768
4769	/* Subtract the ref that was used to protect this instance */
4770	probe->ref--;
4771
4772	if (!probe->ref) {
4773		probe_ops = probe->probe_ops;
4774		/*
4775		 * Sending zero as ip tells probe_ops to free
4776		 * the probe->data itself
4777		 */
4778		if (probe_ops->free)
4779			probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4780		list_del(&probe->list);
4781		kfree(probe);
4782	}
4783	mutex_unlock(&ftrace_lock);
4784}
4785
4786static void acquire_probe_locked(struct ftrace_func_probe *probe)
4787{
4788	/*
4789	 * Add one ref to keep it from being freed when releasing the
4790	 * ftrace_lock mutex.
4791	 */
4792	probe->ref++;
4793}
4794
4795int
4796register_ftrace_function_probe(char *glob, struct trace_array *tr,
4797			       struct ftrace_probe_ops *probe_ops,
4798			       void *data)
4799{
4800	struct ftrace_func_probe *probe = NULL, *iter;
4801	struct ftrace_func_entry *entry;
4802	struct ftrace_hash **orig_hash;
4803	struct ftrace_hash *old_hash;
4804	struct ftrace_hash *hash;
4805	int count = 0;
4806	int size;
4807	int ret;
4808	int i;
4809
4810	if (WARN_ON(!tr))
4811		return -EINVAL;
4812
4813	/* We do not support '!' for function probes */
4814	if (WARN_ON(glob[0] == '!'))
4815		return -EINVAL;
4816
4817
4818	mutex_lock(&ftrace_lock);
4819	/* Check if the probe_ops is already registered */
4820	list_for_each_entry(iter, &tr->func_probes, list) {
4821		if (iter->probe_ops == probe_ops) {
4822			probe = iter;
4823			break;
4824		}
4825	}
4826	if (!probe) {
4827		probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4828		if (!probe) {
4829			mutex_unlock(&ftrace_lock);
4830			return -ENOMEM;
4831		}
4832		probe->probe_ops = probe_ops;
4833		probe->ops.func = function_trace_probe_call;
4834		probe->tr = tr;
4835		ftrace_ops_init(&probe->ops);
4836		list_add(&probe->list, &tr->func_probes);
4837	}
4838
4839	acquire_probe_locked(probe);
4840
4841	mutex_unlock(&ftrace_lock);
4842
4843	/*
4844	 * Note, there's a small window here that the func_hash->filter_hash
4845	 * may be NULL or empty. Need to be careful when reading the loop.
4846	 */
4847	mutex_lock(&probe->ops.func_hash->regex_lock);
4848
4849	orig_hash = &probe->ops.func_hash->filter_hash;
4850	old_hash = *orig_hash;
4851	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4852
4853	if (!hash) {
4854		ret = -ENOMEM;
4855		goto out;
4856	}
4857
4858	ret = ftrace_match_records(hash, glob, strlen(glob));
4859
4860	/* Nothing found? */
4861	if (!ret)
4862		ret = -EINVAL;
4863
4864	if (ret < 0)
4865		goto out;
4866
4867	size = 1 << hash->size_bits;
4868	for (i = 0; i < size; i++) {
4869		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4870			if (ftrace_lookup_ip(old_hash, entry->ip))
4871				continue;
4872			/*
4873			 * The caller might want to do something special
4874			 * for each function we find. We call the callback
4875			 * to give the caller an opportunity to do so.
4876			 */
4877			if (probe_ops->init) {
4878				ret = probe_ops->init(probe_ops, tr,
4879						      entry->ip, data,
4880						      &probe->data);
4881				if (ret < 0) {
4882					if (probe_ops->free && count)
4883						probe_ops->free(probe_ops, tr,
4884								0, probe->data);
4885					probe->data = NULL;
4886					goto out;
4887				}
4888			}
4889			count++;
4890		}
4891	}
4892
4893	mutex_lock(&ftrace_lock);
4894
4895	if (!count) {
4896		/* Nothing was added? */
4897		ret = -EINVAL;
4898		goto out_unlock;
4899	}
4900
4901	ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4902					      hash, 1);
4903	if (ret < 0)
4904		goto err_unlock;
4905
4906	/* One ref for each new function traced */
4907	probe->ref += count;
4908
4909	if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4910		ret = ftrace_startup(&probe->ops, 0);
4911
4912 out_unlock:
4913	mutex_unlock(&ftrace_lock);
4914
4915	if (!ret)
4916		ret = count;
4917 out:
4918	mutex_unlock(&probe->ops.func_hash->regex_lock);
4919	free_ftrace_hash(hash);
4920
4921	release_probe(probe);
4922
4923	return ret;
4924
4925 err_unlock:
4926	if (!probe_ops->free || !count)
4927		goto out_unlock;
4928
4929	/* Failed to do the move, need to call the free functions */
4930	for (i = 0; i < size; i++) {
4931		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4932			if (ftrace_lookup_ip(old_hash, entry->ip))
4933				continue;
4934			probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4935		}
4936	}
4937	goto out_unlock;
4938}
4939
4940int
4941unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4942				      struct ftrace_probe_ops *probe_ops)
4943{
4944	struct ftrace_func_probe *probe = NULL, *iter;
4945	struct ftrace_ops_hash old_hash_ops;
4946	struct ftrace_func_entry *entry;
4947	struct ftrace_glob func_g;
4948	struct ftrace_hash **orig_hash;
4949	struct ftrace_hash *old_hash;
4950	struct ftrace_hash *hash = NULL;
4951	struct hlist_node *tmp;
4952	struct hlist_head hhd;
4953	char str[KSYM_SYMBOL_LEN];
4954	int count = 0;
4955	int i, ret = -ENODEV;
4956	int size;
4957
4958	if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4959		func_g.search = NULL;
4960	else {
4961		int not;
4962
4963		func_g.type = filter_parse_regex(glob, strlen(glob),
4964						 &func_g.search, &not);
4965		func_g.len = strlen(func_g.search);
4966
4967		/* we do not support '!' for function probes */
4968		if (WARN_ON(not))
4969			return -EINVAL;
4970	}
4971
4972	mutex_lock(&ftrace_lock);
4973	/* Check if the probe_ops is already registered */
4974	list_for_each_entry(iter, &tr->func_probes, list) {
4975		if (iter->probe_ops == probe_ops) {
4976			probe = iter;
4977			break;
4978		}
4979	}
4980	if (!probe)
4981		goto err_unlock_ftrace;
4982
4983	ret = -EINVAL;
4984	if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4985		goto err_unlock_ftrace;
4986
4987	acquire_probe_locked(probe);
4988
4989	mutex_unlock(&ftrace_lock);
4990
4991	mutex_lock(&probe->ops.func_hash->regex_lock);
4992
4993	orig_hash = &probe->ops.func_hash->filter_hash;
4994	old_hash = *orig_hash;
4995
4996	if (ftrace_hash_empty(old_hash))
4997		goto out_unlock;
4998
4999	old_hash_ops.filter_hash = old_hash;
5000	/* Probes only have filters */
5001	old_hash_ops.notrace_hash = NULL;
5002
5003	ret = -ENOMEM;
5004	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
5005	if (!hash)
5006		goto out_unlock;
5007
5008	INIT_HLIST_HEAD(&hhd);
5009
5010	size = 1 << hash->size_bits;
5011	for (i = 0; i < size; i++) {
5012		hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
5013
5014			if (func_g.search) {
5015				kallsyms_lookup(entry->ip, NULL, NULL,
5016						NULL, str);
5017				if (!ftrace_match(str, &func_g))
5018					continue;
5019			}
5020			count++;
5021			remove_hash_entry(hash, entry);
5022			hlist_add_head(&entry->hlist, &hhd);
5023		}
5024	}
5025
5026	/* Nothing found? */
5027	if (!count) {
5028		ret = -EINVAL;
5029		goto out_unlock;
5030	}
5031
5032	mutex_lock(&ftrace_lock);
5033
5034	WARN_ON(probe->ref < count);
5035
5036	probe->ref -= count;
5037
5038	if (ftrace_hash_empty(hash))
5039		ftrace_shutdown(&probe->ops, 0);
5040
5041	ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
5042					      hash, 1);
5043
5044	/* still need to update the function call sites */
5045	if (ftrace_enabled && !ftrace_hash_empty(hash))
5046		ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
5047				       &old_hash_ops);
5048	synchronize_rcu();
5049
5050	hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
5051		hlist_del(&entry->hlist);
5052		if (probe_ops->free)
5053			probe_ops->free(probe_ops, tr, entry->ip, probe->data);
5054		kfree(entry);
5055	}
5056	mutex_unlock(&ftrace_lock);
5057
5058 out_unlock:
5059	mutex_unlock(&probe->ops.func_hash->regex_lock);
5060	free_ftrace_hash(hash);
5061
5062	release_probe(probe);
5063
5064	return ret;
5065
5066 err_unlock_ftrace:
5067	mutex_unlock(&ftrace_lock);
5068	return ret;
5069}
5070
5071void clear_ftrace_function_probes(struct trace_array *tr)
5072{
5073	struct ftrace_func_probe *probe, *n;
5074
5075	list_for_each_entry_safe(probe, n, &tr->func_probes, list)
5076		unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
5077}
5078
5079static LIST_HEAD(ftrace_commands);
5080static DEFINE_MUTEX(ftrace_cmd_mutex);
5081
5082/*
5083 * Currently we only register ftrace commands from __init, so mark this
5084 * __init too.
5085 */
5086__init int register_ftrace_command(struct ftrace_func_command *cmd)
5087{
5088	struct ftrace_func_command *p;
5089	int ret = 0;
5090
5091	mutex_lock(&ftrace_cmd_mutex);
5092	list_for_each_entry(p, &ftrace_commands, list) {
5093		if (strcmp(cmd->name, p->name) == 0) {
5094			ret = -EBUSY;
5095			goto out_unlock;
5096		}
5097	}
5098	list_add(&cmd->list, &ftrace_commands);
5099 out_unlock:
5100	mutex_unlock(&ftrace_cmd_mutex);
5101
5102	return ret;
5103}
5104
5105/*
5106 * Currently we only unregister ftrace commands from __init, so mark
5107 * this __init too.
5108 */
5109__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
5110{
5111	struct ftrace_func_command *p, *n;
5112	int ret = -ENODEV;
5113
5114	mutex_lock(&ftrace_cmd_mutex);
5115	list_for_each_entry_safe(p, n, &ftrace_commands, list) {
5116		if (strcmp(cmd->name, p->name) == 0) {
5117			ret = 0;
5118			list_del_init(&p->list);
5119			goto out_unlock;
5120		}
5121	}
5122 out_unlock:
5123	mutex_unlock(&ftrace_cmd_mutex);
5124
5125	return ret;
5126}
5127
5128static int ftrace_process_regex(struct ftrace_iterator *iter,
5129				char *buff, int len, int enable)
5130{
5131	struct ftrace_hash *hash = iter->hash;
5132	struct trace_array *tr = iter->ops->private;
5133	char *func, *command, *next = buff;
5134	struct ftrace_func_command *p;
5135	int ret = -EINVAL;
5136
5137	func = strsep(&next, ":");
5138
5139	if (!next) {
5140		ret = ftrace_match_records(hash, func, len);
5141		if (!ret)
5142			ret = -EINVAL;
5143		if (ret < 0)
5144			return ret;
5145		return 0;
5146	}
5147
5148	/* command found */
5149
5150	command = strsep(&next, ":");
5151
5152	mutex_lock(&ftrace_cmd_mutex);
5153	list_for_each_entry(p, &ftrace_commands, list) {
5154		if (strcmp(p->name, command) == 0) {
5155			ret = p->func(tr, hash, func, command, next, enable);
5156			goto out_unlock;
5157		}
5158	}
5159 out_unlock:
5160	mutex_unlock(&ftrace_cmd_mutex);
5161
5162	return ret;
5163}
5164
5165static ssize_t
5166ftrace_regex_write(struct file *file, const char __user *ubuf,
5167		   size_t cnt, loff_t *ppos, int enable)
5168{
5169	struct ftrace_iterator *iter;
5170	struct trace_parser *parser;
5171	ssize_t ret, read;
5172
5173	if (!cnt)
5174		return 0;
5175
5176	if (file->f_mode & FMODE_READ) {
5177		struct seq_file *m = file->private_data;
5178		iter = m->private;
5179	} else
5180		iter = file->private_data;
5181
5182	if (unlikely(ftrace_disabled))
5183		return -ENODEV;
5184
5185	/* iter->hash is a local copy, so we don't need regex_lock */
5186
5187	parser = &iter->parser;
5188	read = trace_get_user(parser, ubuf, cnt, ppos);
5189
5190	if (read >= 0 && trace_parser_loaded(parser) &&
5191	    !trace_parser_cont(parser)) {
5192		ret = ftrace_process_regex(iter, parser->buffer,
5193					   parser->idx, enable);
5194		trace_parser_clear(parser);
5195		if (ret < 0)
5196			goto out;
5197	}
5198
5199	ret = read;
5200 out:
5201	return ret;
5202}
5203
5204ssize_t
5205ftrace_filter_write(struct file *file, const char __user *ubuf,
5206		    size_t cnt, loff_t *ppos)
5207{
5208	return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
5209}
5210
5211ssize_t
5212ftrace_notrace_write(struct file *file, const char __user *ubuf,
5213		     size_t cnt, loff_t *ppos)
5214{
5215	return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
5216}
5217
5218static int
5219__ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
5220{
5221	struct ftrace_func_entry *entry;
5222
5223	ip = ftrace_location(ip);
5224	if (!ip)
5225		return -EINVAL;
5226
5227	if (remove) {
5228		entry = ftrace_lookup_ip(hash, ip);
5229		if (!entry)
5230			return -ENOENT;
5231		free_hash_entry(hash, entry);
5232		return 0;
5233	}
5234
5235	entry = add_hash_entry(hash, ip);
5236	return entry ? 0 :  -ENOMEM;
5237}
5238
5239static int
5240ftrace_match_addr(struct ftrace_hash *hash, unsigned long *ips,
5241		  unsigned int cnt, int remove)
5242{
5243	unsigned int i;
5244	int err;
5245
5246	for (i = 0; i < cnt; i++) {
5247		err = __ftrace_match_addr(hash, ips[i], remove);
5248		if (err) {
5249			/*
5250			 * This expects the @hash is a temporary hash and if this
5251			 * fails the caller must free the @hash.
5252			 */
5253			return err;
5254		}
5255	}
5256	return 0;
5257}
5258
5259static int
5260ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
5261		unsigned long *ips, unsigned int cnt,
5262		int remove, int reset, int enable)
5263{
5264	struct ftrace_hash **orig_hash;
5265	struct ftrace_hash *hash;
5266	int ret;
5267
5268	if (unlikely(ftrace_disabled))
5269		return -ENODEV;
5270
5271	mutex_lock(&ops->func_hash->regex_lock);
5272
5273	if (enable)
5274		orig_hash = &ops->func_hash->filter_hash;
5275	else
5276		orig_hash = &ops->func_hash->notrace_hash;
5277
5278	if (reset)
5279		hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5280	else
5281		hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
5282
5283	if (!hash) {
5284		ret = -ENOMEM;
5285		goto out_regex_unlock;
5286	}
5287
5288	if (buf && !ftrace_match_records(hash, buf, len)) {
5289		ret = -EINVAL;
5290		goto out_regex_unlock;
5291	}
5292	if (ips) {
5293		ret = ftrace_match_addr(hash, ips, cnt, remove);
5294		if (ret < 0)
5295			goto out_regex_unlock;
5296	}
5297
5298	mutex_lock(&ftrace_lock);
5299	ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
5300	mutex_unlock(&ftrace_lock);
5301
5302 out_regex_unlock:
5303	mutex_unlock(&ops->func_hash->regex_lock);
5304
5305	free_ftrace_hash(hash);
5306	return ret;
5307}
5308
5309static int
5310ftrace_set_addr(struct ftrace_ops *ops, unsigned long *ips, unsigned int cnt,
5311		int remove, int reset, int enable)
5312{
5313	return ftrace_set_hash(ops, NULL, 0, ips, cnt, remove, reset, enable);
5314}
5315
5316#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5317
5318struct ftrace_direct_func {
5319	struct list_head	next;
5320	unsigned long		addr;
5321	int			count;
5322};
5323
5324static LIST_HEAD(ftrace_direct_funcs);
5325
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5326static int register_ftrace_function_nolock(struct ftrace_ops *ops);
5327
5328/*
5329 * If there are multiple ftrace_ops, use SAVE_REGS by default, so that direct
5330 * call will be jumped from ftrace_regs_caller. Only if the architecture does
5331 * not support ftrace_regs_caller but direct_call, use SAVE_ARGS so that it
5332 * jumps from ftrace_caller for multiple ftrace_ops.
 
 
 
 
 
 
 
 
 
 
 
5333 */
5334#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS
5335#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_ARGS)
5336#else
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5337#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS)
5338#endif
5339
5340static int check_direct_multi(struct ftrace_ops *ops)
5341{
5342	if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5343		return -EINVAL;
5344	if ((ops->flags & MULTI_FLAGS) != MULTI_FLAGS)
5345		return -EINVAL;
5346	return 0;
5347}
5348
5349static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long addr)
5350{
5351	struct ftrace_func_entry *entry, *del;
5352	int size, i;
5353
5354	size = 1 << hash->size_bits;
5355	for (i = 0; i < size; i++) {
5356		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5357			del = __ftrace_lookup_ip(direct_functions, entry->ip);
5358			if (del && del->direct == addr) {
5359				remove_hash_entry(direct_functions, del);
5360				kfree(del);
5361			}
5362		}
5363	}
5364}
5365
5366/**
5367 * register_ftrace_direct - Call a custom trampoline directly
5368 * for multiple functions registered in @ops
5369 * @ops: The address of the struct ftrace_ops object
5370 * @addr: The address of the trampoline to call at @ops functions
5371 *
5372 * This is used to connect a direct calls to @addr from the nop locations
5373 * of the functions registered in @ops (with by ftrace_set_filter_ip
5374 * function).
5375 *
5376 * The location that it calls (@addr) must be able to handle a direct call,
5377 * and save the parameters of the function being traced, and restore them
5378 * (or inject new ones if needed), before returning.
5379 *
5380 * Returns:
5381 *  0 on success
5382 *  -EINVAL  - The @ops object was already registered with this call or
5383 *             when there are no functions in @ops object.
5384 *  -EBUSY   - Another direct function is already attached (there can be only one)
5385 *  -ENODEV  - @ip does not point to a ftrace nop location (or not supported)
5386 *  -ENOMEM  - There was an allocation failure.
5387 */
5388int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5389{
5390	struct ftrace_hash *hash, *new_hash = NULL, *free_hash = NULL;
5391	struct ftrace_func_entry *entry, *new;
5392	int err = -EBUSY, size, i;
5393
5394	if (ops->func || ops->trampoline)
5395		return -EINVAL;
5396	if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5397		return -EINVAL;
5398	if (ops->flags & FTRACE_OPS_FL_ENABLED)
5399		return -EINVAL;
5400
5401	hash = ops->func_hash->filter_hash;
5402	if (ftrace_hash_empty(hash))
5403		return -EINVAL;
5404
5405	mutex_lock(&direct_mutex);
5406
5407	/* Make sure requested entries are not already registered.. */
5408	size = 1 << hash->size_bits;
5409	for (i = 0; i < size; i++) {
5410		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5411			if (ftrace_find_rec_direct(entry->ip))
5412				goto out_unlock;
5413		}
5414	}
5415
 
5416	err = -ENOMEM;
5417
5418	/* Make a copy hash to place the new and the old entries in */
5419	size = hash->count + direct_functions->count;
5420	if (size > 32)
5421		size = 32;
5422	new_hash = alloc_ftrace_hash(fls(size));
5423	if (!new_hash)
5424		goto out_unlock;
5425
5426	/* Now copy over the existing direct entries */
5427	size = 1 << direct_functions->size_bits;
5428	for (i = 0; i < size; i++) {
5429		hlist_for_each_entry(entry, &direct_functions->buckets[i], hlist) {
5430			new = add_hash_entry(new_hash, entry->ip);
5431			if (!new)
5432				goto out_unlock;
5433			new->direct = entry->direct;
5434		}
5435	}
5436
5437	/* ... and add the new entries */
5438	size = 1 << hash->size_bits;
5439	for (i = 0; i < size; i++) {
5440		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5441			new = add_hash_entry(new_hash, entry->ip);
5442			if (!new)
5443				goto out_unlock;
5444			/* Update both the copy and the hash entry */
5445			new->direct = addr;
5446			entry->direct = addr;
5447		}
5448	}
5449
5450	free_hash = direct_functions;
5451	rcu_assign_pointer(direct_functions, new_hash);
5452	new_hash = NULL;
5453
5454	ops->func = call_direct_funcs;
5455	ops->flags = MULTI_FLAGS;
5456	ops->trampoline = FTRACE_REGS_ADDR;
5457	ops->direct_call = addr;
5458
5459	err = register_ftrace_function_nolock(ops);
5460
 
 
 
 
5461 out_unlock:
5462	mutex_unlock(&direct_mutex);
5463
5464	if (free_hash && free_hash != EMPTY_HASH) {
5465		synchronize_rcu_tasks();
5466		free_ftrace_hash(free_hash);
5467	}
5468
5469	if (new_hash)
5470		free_ftrace_hash(new_hash);
5471
5472	return err;
5473}
5474EXPORT_SYMBOL_GPL(register_ftrace_direct);
5475
5476/**
5477 * unregister_ftrace_direct - Remove calls to custom trampoline
5478 * previously registered by register_ftrace_direct for @ops object.
5479 * @ops: The address of the struct ftrace_ops object
5480 *
5481 * This is used to remove a direct calls to @addr from the nop locations
5482 * of the functions registered in @ops (with by ftrace_set_filter_ip
5483 * function).
5484 *
5485 * Returns:
5486 *  0 on success
5487 *  -EINVAL - The @ops object was not properly registered.
5488 */
5489int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
5490			     bool free_filters)
5491{
5492	struct ftrace_hash *hash = ops->func_hash->filter_hash;
5493	int err;
5494
5495	if (check_direct_multi(ops))
5496		return -EINVAL;
5497	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5498		return -EINVAL;
5499
5500	mutex_lock(&direct_mutex);
5501	err = unregister_ftrace_function(ops);
5502	remove_direct_functions_hash(hash, addr);
5503	mutex_unlock(&direct_mutex);
5504
5505	/* cleanup for possible another register call */
5506	ops->func = NULL;
5507	ops->trampoline = 0;
5508
5509	if (free_filters)
5510		ftrace_free_filter(ops);
5511	return err;
5512}
5513EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5514
5515static int
5516__modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5517{
5518	struct ftrace_hash *hash;
5519	struct ftrace_func_entry *entry, *iter;
5520	static struct ftrace_ops tmp_ops = {
5521		.func		= ftrace_stub,
5522		.flags		= FTRACE_OPS_FL_STUB,
5523	};
5524	int i, size;
5525	int err;
5526
5527	lockdep_assert_held_once(&direct_mutex);
5528
5529	/* Enable the tmp_ops to have the same functions as the direct ops */
5530	ftrace_ops_init(&tmp_ops);
5531	tmp_ops.func_hash = ops->func_hash;
5532	tmp_ops.direct_call = addr;
5533
5534	err = register_ftrace_function_nolock(&tmp_ops);
5535	if (err)
5536		return err;
5537
5538	/*
5539	 * Now the ftrace_ops_list_func() is called to do the direct callers.
5540	 * We can safely change the direct functions attached to each entry.
5541	 */
5542	mutex_lock(&ftrace_lock);
5543
5544	hash = ops->func_hash->filter_hash;
5545	size = 1 << hash->size_bits;
5546	for (i = 0; i < size; i++) {
5547		hlist_for_each_entry(iter, &hash->buckets[i], hlist) {
5548			entry = __ftrace_lookup_ip(direct_functions, iter->ip);
5549			if (!entry)
5550				continue;
5551			entry->direct = addr;
5552		}
5553	}
5554	/* Prevent store tearing if a trampoline concurrently accesses the value */
5555	WRITE_ONCE(ops->direct_call, addr);
5556
5557	mutex_unlock(&ftrace_lock);
5558
5559	/* Removing the tmp_ops will add the updated direct callers to the functions */
5560	unregister_ftrace_function(&tmp_ops);
5561
5562	return err;
5563}
5564
5565/**
5566 * modify_ftrace_direct_nolock - Modify an existing direct 'multi' call
5567 * to call something else
5568 * @ops: The address of the struct ftrace_ops object
5569 * @addr: The address of the new trampoline to call at @ops functions
5570 *
5571 * This is used to unregister currently registered direct caller and
5572 * register new one @addr on functions registered in @ops object.
5573 *
5574 * Note there's window between ftrace_shutdown and ftrace_startup calls
5575 * where there will be no callbacks called.
5576 *
5577 * Caller should already have direct_mutex locked, so we don't lock
5578 * direct_mutex here.
5579 *
5580 * Returns: zero on success. Non zero on error, which includes:
5581 *  -EINVAL - The @ops object was not properly registered.
5582 */
5583int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr)
5584{
5585	if (check_direct_multi(ops))
5586		return -EINVAL;
5587	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5588		return -EINVAL;
5589
5590	return __modify_ftrace_direct(ops, addr);
5591}
5592EXPORT_SYMBOL_GPL(modify_ftrace_direct_nolock);
5593
5594/**
5595 * modify_ftrace_direct - Modify an existing direct 'multi' call
5596 * to call something else
5597 * @ops: The address of the struct ftrace_ops object
5598 * @addr: The address of the new trampoline to call at @ops functions
5599 *
5600 * This is used to unregister currently registered direct caller and
5601 * register new one @addr on functions registered in @ops object.
5602 *
5603 * Note there's window between ftrace_shutdown and ftrace_startup calls
5604 * where there will be no callbacks called.
5605 *
5606 * Returns: zero on success. Non zero on error, which includes:
5607 *  -EINVAL - The @ops object was not properly registered.
5608 */
5609int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5610{
5611	int err;
5612
5613	if (check_direct_multi(ops))
5614		return -EINVAL;
5615	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5616		return -EINVAL;
5617
5618	mutex_lock(&direct_mutex);
5619	err = __modify_ftrace_direct(ops, addr);
5620	mutex_unlock(&direct_mutex);
5621	return err;
5622}
5623EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5624#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5625
5626/**
5627 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5628 * @ops - the ops to set the filter with
5629 * @ip - the address to add to or remove from the filter.
5630 * @remove - non zero to remove the ip from the filter
5631 * @reset - non zero to reset all filters before applying this filter.
5632 *
5633 * Filters denote which functions should be enabled when tracing is enabled
5634 * If @ip is NULL, it fails to update filter.
5635 *
5636 * This can allocate memory which must be freed before @ops can be freed,
5637 * either by removing each filtered addr or by using
5638 * ftrace_free_filter(@ops).
5639 */
5640int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5641			 int remove, int reset)
5642{
5643	ftrace_ops_init(ops);
5644	return ftrace_set_addr(ops, &ip, 1, remove, reset, 1);
5645}
5646EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5647
5648/**
5649 * ftrace_set_filter_ips - set functions to filter on in ftrace by addresses
5650 * @ops - the ops to set the filter with
5651 * @ips - the array of addresses to add to or remove from the filter.
5652 * @cnt - the number of addresses in @ips
5653 * @remove - non zero to remove ips from the filter
5654 * @reset - non zero to reset all filters before applying this filter.
5655 *
5656 * Filters denote which functions should be enabled when tracing is enabled
5657 * If @ips array or any ip specified within is NULL , it fails to update filter.
5658 *
5659 * This can allocate memory which must be freed before @ops can be freed,
5660 * either by removing each filtered addr or by using
5661 * ftrace_free_filter(@ops).
5662*/
5663int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
5664			  unsigned int cnt, int remove, int reset)
5665{
5666	ftrace_ops_init(ops);
5667	return ftrace_set_addr(ops, ips, cnt, remove, reset, 1);
5668}
5669EXPORT_SYMBOL_GPL(ftrace_set_filter_ips);
5670
5671/**
5672 * ftrace_ops_set_global_filter - setup ops to use global filters
5673 * @ops - the ops which will use the global filters
5674 *
5675 * ftrace users who need global function trace filtering should call this.
5676 * It can set the global filter only if ops were not initialized before.
5677 */
5678void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5679{
5680	if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5681		return;
5682
5683	ftrace_ops_init(ops);
5684	ops->func_hash = &global_ops.local_hash;
5685}
5686EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5687
5688static int
5689ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5690		 int reset, int enable)
5691{
5692	return ftrace_set_hash(ops, buf, len, NULL, 0, 0, reset, enable);
5693}
5694
5695/**
5696 * ftrace_set_filter - set a function to filter on in ftrace
5697 * @ops - the ops to set the filter with
5698 * @buf - the string that holds the function filter text.
5699 * @len - the length of the string.
5700 * @reset - non zero to reset all filters before applying this filter.
5701 *
5702 * Filters denote which functions should be enabled when tracing is enabled.
5703 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5704 *
5705 * This can allocate memory which must be freed before @ops can be freed,
5706 * either by removing each filtered addr or by using
5707 * ftrace_free_filter(@ops).
5708 */
5709int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5710		       int len, int reset)
5711{
5712	ftrace_ops_init(ops);
5713	return ftrace_set_regex(ops, buf, len, reset, 1);
5714}
5715EXPORT_SYMBOL_GPL(ftrace_set_filter);
5716
5717/**
5718 * ftrace_set_notrace - set a function to not trace in ftrace
5719 * @ops - the ops to set the notrace filter with
5720 * @buf - the string that holds the function notrace text.
5721 * @len - the length of the string.
5722 * @reset - non zero to reset all filters before applying this filter.
5723 *
5724 * Notrace Filters denote which functions should not be enabled when tracing
5725 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5726 * for tracing.
5727 *
5728 * This can allocate memory which must be freed before @ops can be freed,
5729 * either by removing each filtered addr or by using
5730 * ftrace_free_filter(@ops).
5731 */
5732int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5733			int len, int reset)
5734{
5735	ftrace_ops_init(ops);
5736	return ftrace_set_regex(ops, buf, len, reset, 0);
5737}
5738EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5739/**
5740 * ftrace_set_global_filter - set a function to filter on with global tracers
5741 * @buf - the string that holds the function filter text.
5742 * @len - the length of the string.
5743 * @reset - non zero to reset all filters before applying this filter.
5744 *
5745 * Filters denote which functions should be enabled when tracing is enabled.
5746 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5747 */
5748void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5749{
5750	ftrace_set_regex(&global_ops, buf, len, reset, 1);
5751}
5752EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5753
5754/**
5755 * ftrace_set_global_notrace - set a function to not trace with global tracers
5756 * @buf - the string that holds the function notrace text.
5757 * @len - the length of the string.
5758 * @reset - non zero to reset all filters before applying this filter.
5759 *
5760 * Notrace Filters denote which functions should not be enabled when tracing
5761 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5762 * for tracing.
5763 */
5764void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5765{
5766	ftrace_set_regex(&global_ops, buf, len, reset, 0);
5767}
5768EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5769
5770/*
5771 * command line interface to allow users to set filters on boot up.
5772 */
5773#define FTRACE_FILTER_SIZE		COMMAND_LINE_SIZE
5774static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5775static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5776
5777/* Used by function selftest to not test if filter is set */
5778bool ftrace_filter_param __initdata;
5779
5780static int __init set_ftrace_notrace(char *str)
5781{
5782	ftrace_filter_param = true;
5783	strscpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5784	return 1;
5785}
5786__setup("ftrace_notrace=", set_ftrace_notrace);
5787
5788static int __init set_ftrace_filter(char *str)
5789{
5790	ftrace_filter_param = true;
5791	strscpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5792	return 1;
5793}
5794__setup("ftrace_filter=", set_ftrace_filter);
5795
5796#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5797static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5798static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5799static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5800
5801static int __init set_graph_function(char *str)
5802{
5803	strscpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5804	return 1;
5805}
5806__setup("ftrace_graph_filter=", set_graph_function);
5807
5808static int __init set_graph_notrace_function(char *str)
5809{
5810	strscpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5811	return 1;
5812}
5813__setup("ftrace_graph_notrace=", set_graph_notrace_function);
5814
5815static int __init set_graph_max_depth_function(char *str)
5816{
5817	if (!str)
5818		return 0;
5819	fgraph_max_depth = simple_strtoul(str, NULL, 0);
5820	return 1;
5821}
5822__setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5823
5824static void __init set_ftrace_early_graph(char *buf, int enable)
5825{
5826	int ret;
5827	char *func;
5828	struct ftrace_hash *hash;
5829
5830	hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5831	if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
5832		return;
5833
5834	while (buf) {
5835		func = strsep(&buf, ",");
5836		/* we allow only one expression at a time */
5837		ret = ftrace_graph_set_hash(hash, func);
5838		if (ret)
5839			printk(KERN_DEBUG "ftrace: function %s not "
5840					  "traceable\n", func);
5841	}
5842
5843	if (enable)
5844		ftrace_graph_hash = hash;
5845	else
5846		ftrace_graph_notrace_hash = hash;
5847}
5848#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5849
5850void __init
5851ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5852{
5853	char *func;
5854
5855	ftrace_ops_init(ops);
5856
5857	while (buf) {
5858		func = strsep(&buf, ",");
5859		ftrace_set_regex(ops, func, strlen(func), 0, enable);
5860	}
5861}
5862
5863static void __init set_ftrace_early_filters(void)
5864{
5865	if (ftrace_filter_buf[0])
5866		ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5867	if (ftrace_notrace_buf[0])
5868		ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5869#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5870	if (ftrace_graph_buf[0])
5871		set_ftrace_early_graph(ftrace_graph_buf, 1);
5872	if (ftrace_graph_notrace_buf[0])
5873		set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5874#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5875}
5876
5877int ftrace_regex_release(struct inode *inode, struct file *file)
5878{
5879	struct seq_file *m = (struct seq_file *)file->private_data;
5880	struct ftrace_iterator *iter;
5881	struct ftrace_hash **orig_hash;
5882	struct trace_parser *parser;
5883	int filter_hash;
5884
5885	if (file->f_mode & FMODE_READ) {
5886		iter = m->private;
5887		seq_release(inode, file);
5888	} else
5889		iter = file->private_data;
5890
5891	parser = &iter->parser;
5892	if (trace_parser_loaded(parser)) {
5893		int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
5894
5895		ftrace_process_regex(iter, parser->buffer,
5896				     parser->idx, enable);
5897	}
5898
5899	trace_parser_put(parser);
5900
5901	mutex_lock(&iter->ops->func_hash->regex_lock);
5902
5903	if (file->f_mode & FMODE_WRITE) {
5904		filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5905
5906		if (filter_hash) {
5907			orig_hash = &iter->ops->func_hash->filter_hash;
5908			if (iter->tr) {
5909				if (list_empty(&iter->tr->mod_trace))
5910					iter->hash->flags &= ~FTRACE_HASH_FL_MOD;
5911				else
5912					iter->hash->flags |= FTRACE_HASH_FL_MOD;
5913			}
5914		} else
5915			orig_hash = &iter->ops->func_hash->notrace_hash;
5916
5917		mutex_lock(&ftrace_lock);
5918		ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5919						      iter->hash, filter_hash);
5920		mutex_unlock(&ftrace_lock);
5921	} else {
5922		/* For read only, the hash is the ops hash */
5923		iter->hash = NULL;
5924	}
5925
5926	mutex_unlock(&iter->ops->func_hash->regex_lock);
5927	free_ftrace_hash(iter->hash);
5928	if (iter->tr)
5929		trace_array_put(iter->tr);
5930	kfree(iter);
5931
5932	return 0;
5933}
5934
5935static const struct file_operations ftrace_avail_fops = {
5936	.open = ftrace_avail_open,
5937	.read = seq_read,
5938	.llseek = seq_lseek,
5939	.release = seq_release_private,
5940};
5941
5942static const struct file_operations ftrace_enabled_fops = {
5943	.open = ftrace_enabled_open,
5944	.read = seq_read,
5945	.llseek = seq_lseek,
5946	.release = seq_release_private,
5947};
5948
5949static const struct file_operations ftrace_touched_fops = {
5950	.open = ftrace_touched_open,
5951	.read = seq_read,
5952	.llseek = seq_lseek,
5953	.release = seq_release_private,
5954};
5955
5956static const struct file_operations ftrace_avail_addrs_fops = {
5957	.open = ftrace_avail_addrs_open,
5958	.read = seq_read,
5959	.llseek = seq_lseek,
5960	.release = seq_release_private,
5961};
5962
5963static const struct file_operations ftrace_filter_fops = {
5964	.open = ftrace_filter_open,
5965	.read = seq_read,
5966	.write = ftrace_filter_write,
5967	.llseek = tracing_lseek,
5968	.release = ftrace_regex_release,
5969};
5970
5971static const struct file_operations ftrace_notrace_fops = {
5972	.open = ftrace_notrace_open,
5973	.read = seq_read,
5974	.write = ftrace_notrace_write,
5975	.llseek = tracing_lseek,
5976	.release = ftrace_regex_release,
5977};
5978
5979#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5980
5981static DEFINE_MUTEX(graph_lock);
5982
5983struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5984struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5985
5986enum graph_filter_type {
5987	GRAPH_FILTER_NOTRACE	= 0,
5988	GRAPH_FILTER_FUNCTION,
5989};
5990
5991#define FTRACE_GRAPH_EMPTY	((void *)1)
5992
5993struct ftrace_graph_data {
5994	struct ftrace_hash		*hash;
5995	struct ftrace_func_entry	*entry;
5996	int				idx;   /* for hash table iteration */
5997	enum graph_filter_type		type;
5998	struct ftrace_hash		*new_hash;
5999	const struct seq_operations	*seq_ops;
6000	struct trace_parser		parser;
6001};
6002
6003static void *
6004__g_next(struct seq_file *m, loff_t *pos)
6005{
6006	struct ftrace_graph_data *fgd = m->private;
6007	struct ftrace_func_entry *entry = fgd->entry;
6008	struct hlist_head *head;
6009	int i, idx = fgd->idx;
6010
6011	if (*pos >= fgd->hash->count)
6012		return NULL;
6013
6014	if (entry) {
6015		hlist_for_each_entry_continue(entry, hlist) {
6016			fgd->entry = entry;
6017			return entry;
6018		}
6019
6020		idx++;
6021	}
6022
6023	for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
6024		head = &fgd->hash->buckets[i];
6025		hlist_for_each_entry(entry, head, hlist) {
6026			fgd->entry = entry;
6027			fgd->idx = i;
6028			return entry;
6029		}
6030	}
6031	return NULL;
6032}
6033
6034static void *
6035g_next(struct seq_file *m, void *v, loff_t *pos)
6036{
6037	(*pos)++;
6038	return __g_next(m, pos);
6039}
6040
6041static void *g_start(struct seq_file *m, loff_t *pos)
6042{
6043	struct ftrace_graph_data *fgd = m->private;
6044
6045	mutex_lock(&graph_lock);
6046
6047	if (fgd->type == GRAPH_FILTER_FUNCTION)
6048		fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6049					lockdep_is_held(&graph_lock));
6050	else
6051		fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6052					lockdep_is_held(&graph_lock));
6053
6054	/* Nothing, tell g_show to print all functions are enabled */
6055	if (ftrace_hash_empty(fgd->hash) && !*pos)
6056		return FTRACE_GRAPH_EMPTY;
6057
6058	fgd->idx = 0;
6059	fgd->entry = NULL;
6060	return __g_next(m, pos);
6061}
6062
6063static void g_stop(struct seq_file *m, void *p)
6064{
6065	mutex_unlock(&graph_lock);
6066}
6067
6068static int g_show(struct seq_file *m, void *v)
6069{
6070	struct ftrace_func_entry *entry = v;
6071
6072	if (!entry)
6073		return 0;
6074
6075	if (entry == FTRACE_GRAPH_EMPTY) {
6076		struct ftrace_graph_data *fgd = m->private;
6077
6078		if (fgd->type == GRAPH_FILTER_FUNCTION)
6079			seq_puts(m, "#### all functions enabled ####\n");
6080		else
6081			seq_puts(m, "#### no functions disabled ####\n");
6082		return 0;
6083	}
6084
6085	seq_printf(m, "%ps\n", (void *)entry->ip);
6086
6087	return 0;
6088}
6089
6090static const struct seq_operations ftrace_graph_seq_ops = {
6091	.start = g_start,
6092	.next = g_next,
6093	.stop = g_stop,
6094	.show = g_show,
6095};
6096
6097static int
6098__ftrace_graph_open(struct inode *inode, struct file *file,
6099		    struct ftrace_graph_data *fgd)
6100{
6101	int ret;
6102	struct ftrace_hash *new_hash = NULL;
6103
6104	ret = security_locked_down(LOCKDOWN_TRACEFS);
6105	if (ret)
6106		return ret;
6107
6108	if (file->f_mode & FMODE_WRITE) {
6109		const int size_bits = FTRACE_HASH_DEFAULT_BITS;
6110
6111		if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
6112			return -ENOMEM;
6113
6114		if (file->f_flags & O_TRUNC)
6115			new_hash = alloc_ftrace_hash(size_bits);
6116		else
6117			new_hash = alloc_and_copy_ftrace_hash(size_bits,
6118							      fgd->hash);
6119		if (!new_hash) {
6120			ret = -ENOMEM;
6121			goto out;
6122		}
6123	}
6124
6125	if (file->f_mode & FMODE_READ) {
6126		ret = seq_open(file, &ftrace_graph_seq_ops);
6127		if (!ret) {
6128			struct seq_file *m = file->private_data;
6129			m->private = fgd;
6130		} else {
6131			/* Failed */
6132			free_ftrace_hash(new_hash);
6133			new_hash = NULL;
6134		}
6135	} else
6136		file->private_data = fgd;
6137
6138out:
6139	if (ret < 0 && file->f_mode & FMODE_WRITE)
6140		trace_parser_put(&fgd->parser);
6141
6142	fgd->new_hash = new_hash;
6143
6144	/*
6145	 * All uses of fgd->hash must be taken with the graph_lock
6146	 * held. The graph_lock is going to be released, so force
6147	 * fgd->hash to be reinitialized when it is taken again.
6148	 */
6149	fgd->hash = NULL;
6150
6151	return ret;
6152}
6153
6154static int
6155ftrace_graph_open(struct inode *inode, struct file *file)
6156{
6157	struct ftrace_graph_data *fgd;
6158	int ret;
6159
6160	if (unlikely(ftrace_disabled))
6161		return -ENODEV;
6162
6163	fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6164	if (fgd == NULL)
6165		return -ENOMEM;
6166
6167	mutex_lock(&graph_lock);
6168
6169	fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6170					lockdep_is_held(&graph_lock));
6171	fgd->type = GRAPH_FILTER_FUNCTION;
6172	fgd->seq_ops = &ftrace_graph_seq_ops;
6173
6174	ret = __ftrace_graph_open(inode, file, fgd);
6175	if (ret < 0)
6176		kfree(fgd);
6177
6178	mutex_unlock(&graph_lock);
6179	return ret;
6180}
6181
6182static int
6183ftrace_graph_notrace_open(struct inode *inode, struct file *file)
6184{
6185	struct ftrace_graph_data *fgd;
6186	int ret;
6187
6188	if (unlikely(ftrace_disabled))
6189		return -ENODEV;
6190
6191	fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6192	if (fgd == NULL)
6193		return -ENOMEM;
6194
6195	mutex_lock(&graph_lock);
6196
6197	fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6198					lockdep_is_held(&graph_lock));
6199	fgd->type = GRAPH_FILTER_NOTRACE;
6200	fgd->seq_ops = &ftrace_graph_seq_ops;
6201
6202	ret = __ftrace_graph_open(inode, file, fgd);
6203	if (ret < 0)
6204		kfree(fgd);
6205
6206	mutex_unlock(&graph_lock);
6207	return ret;
6208}
6209
6210static int
6211ftrace_graph_release(struct inode *inode, struct file *file)
6212{
6213	struct ftrace_graph_data *fgd;
6214	struct ftrace_hash *old_hash, *new_hash;
6215	struct trace_parser *parser;
6216	int ret = 0;
6217
6218	if (file->f_mode & FMODE_READ) {
6219		struct seq_file *m = file->private_data;
6220
6221		fgd = m->private;
6222		seq_release(inode, file);
6223	} else {
6224		fgd = file->private_data;
6225	}
6226
6227
6228	if (file->f_mode & FMODE_WRITE) {
6229
6230		parser = &fgd->parser;
6231
6232		if (trace_parser_loaded((parser))) {
6233			ret = ftrace_graph_set_hash(fgd->new_hash,
6234						    parser->buffer);
6235		}
6236
6237		trace_parser_put(parser);
6238
6239		new_hash = __ftrace_hash_move(fgd->new_hash);
6240		if (!new_hash) {
6241			ret = -ENOMEM;
6242			goto out;
6243		}
6244
6245		mutex_lock(&graph_lock);
6246
6247		if (fgd->type == GRAPH_FILTER_FUNCTION) {
6248			old_hash = rcu_dereference_protected(ftrace_graph_hash,
6249					lockdep_is_held(&graph_lock));
6250			rcu_assign_pointer(ftrace_graph_hash, new_hash);
6251		} else {
6252			old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6253					lockdep_is_held(&graph_lock));
6254			rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
6255		}
6256
6257		mutex_unlock(&graph_lock);
6258
6259		/*
6260		 * We need to do a hard force of sched synchronization.
6261		 * This is because we use preempt_disable() to do RCU, but
6262		 * the function tracers can be called where RCU is not watching
6263		 * (like before user_exit()). We can not rely on the RCU
6264		 * infrastructure to do the synchronization, thus we must do it
6265		 * ourselves.
6266		 */
6267		if (old_hash != EMPTY_HASH)
6268			synchronize_rcu_tasks_rude();
6269
6270		free_ftrace_hash(old_hash);
6271	}
6272
6273 out:
6274	free_ftrace_hash(fgd->new_hash);
6275	kfree(fgd);
6276
6277	return ret;
6278}
6279
6280static int
6281ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
6282{
6283	struct ftrace_glob func_g;
6284	struct dyn_ftrace *rec;
6285	struct ftrace_page *pg;
6286	struct ftrace_func_entry *entry;
6287	int fail = 1;
6288	int not;
6289
6290	/* decode regex */
6291	func_g.type = filter_parse_regex(buffer, strlen(buffer),
6292					 &func_g.search, &not);
6293
6294	func_g.len = strlen(func_g.search);
6295
6296	mutex_lock(&ftrace_lock);
6297
6298	if (unlikely(ftrace_disabled)) {
6299		mutex_unlock(&ftrace_lock);
6300		return -ENODEV;
6301	}
6302
6303	do_for_each_ftrace_rec(pg, rec) {
6304
6305		if (rec->flags & FTRACE_FL_DISABLED)
6306			continue;
6307
6308		if (ftrace_match_record(rec, &func_g, NULL, 0)) {
6309			entry = ftrace_lookup_ip(hash, rec->ip);
6310
6311			if (!not) {
6312				fail = 0;
6313
6314				if (entry)
6315					continue;
6316				if (add_hash_entry(hash, rec->ip) == NULL)
6317					goto out;
6318			} else {
6319				if (entry) {
6320					free_hash_entry(hash, entry);
6321					fail = 0;
6322				}
6323			}
6324		}
6325	} while_for_each_ftrace_rec();
6326out:
6327	mutex_unlock(&ftrace_lock);
6328
6329	if (fail)
6330		return -EINVAL;
6331
6332	return 0;
6333}
6334
6335static ssize_t
6336ftrace_graph_write(struct file *file, const char __user *ubuf,
6337		   size_t cnt, loff_t *ppos)
6338{
6339	ssize_t read, ret = 0;
6340	struct ftrace_graph_data *fgd = file->private_data;
6341	struct trace_parser *parser;
6342
6343	if (!cnt)
6344		return 0;
6345
6346	/* Read mode uses seq functions */
6347	if (file->f_mode & FMODE_READ) {
6348		struct seq_file *m = file->private_data;
6349		fgd = m->private;
6350	}
6351
6352	parser = &fgd->parser;
6353
6354	read = trace_get_user(parser, ubuf, cnt, ppos);
6355
6356	if (read >= 0 && trace_parser_loaded(parser) &&
6357	    !trace_parser_cont(parser)) {
6358
6359		ret = ftrace_graph_set_hash(fgd->new_hash,
6360					    parser->buffer);
6361		trace_parser_clear(parser);
6362	}
6363
6364	if (!ret)
6365		ret = read;
6366
6367	return ret;
6368}
6369
6370static const struct file_operations ftrace_graph_fops = {
6371	.open		= ftrace_graph_open,
6372	.read		= seq_read,
6373	.write		= ftrace_graph_write,
6374	.llseek		= tracing_lseek,
6375	.release	= ftrace_graph_release,
6376};
6377
6378static const struct file_operations ftrace_graph_notrace_fops = {
6379	.open		= ftrace_graph_notrace_open,
6380	.read		= seq_read,
6381	.write		= ftrace_graph_write,
6382	.llseek		= tracing_lseek,
6383	.release	= ftrace_graph_release,
6384};
6385#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6386
6387void ftrace_create_filter_files(struct ftrace_ops *ops,
6388				struct dentry *parent)
6389{
6390
6391	trace_create_file("set_ftrace_filter", TRACE_MODE_WRITE, parent,
6392			  ops, &ftrace_filter_fops);
6393
6394	trace_create_file("set_ftrace_notrace", TRACE_MODE_WRITE, parent,
6395			  ops, &ftrace_notrace_fops);
6396}
6397
6398/*
6399 * The name "destroy_filter_files" is really a misnomer. Although
6400 * in the future, it may actually delete the files, but this is
6401 * really intended to make sure the ops passed in are disabled
6402 * and that when this function returns, the caller is free to
6403 * free the ops.
6404 *
6405 * The "destroy" name is only to match the "create" name that this
6406 * should be paired with.
6407 */
6408void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6409{
6410	mutex_lock(&ftrace_lock);
6411	if (ops->flags & FTRACE_OPS_FL_ENABLED)
6412		ftrace_shutdown(ops, 0);
6413	ops->flags |= FTRACE_OPS_FL_DELETED;
6414	ftrace_free_filter(ops);
6415	mutex_unlock(&ftrace_lock);
6416}
6417
6418static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6419{
6420
6421	trace_create_file("available_filter_functions", TRACE_MODE_READ,
6422			d_tracer, NULL, &ftrace_avail_fops);
6423
6424	trace_create_file("available_filter_functions_addrs", TRACE_MODE_READ,
6425			d_tracer, NULL, &ftrace_avail_addrs_fops);
6426
6427	trace_create_file("enabled_functions", TRACE_MODE_READ,
6428			d_tracer, NULL, &ftrace_enabled_fops);
6429
6430	trace_create_file("touched_functions", TRACE_MODE_READ,
6431			d_tracer, NULL, &ftrace_touched_fops);
6432
6433	ftrace_create_filter_files(&global_ops, d_tracer);
6434
6435#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6436	trace_create_file("set_graph_function", TRACE_MODE_WRITE, d_tracer,
6437				    NULL,
6438				    &ftrace_graph_fops);
6439	trace_create_file("set_graph_notrace", TRACE_MODE_WRITE, d_tracer,
6440				    NULL,
6441				    &ftrace_graph_notrace_fops);
6442#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6443
6444	return 0;
6445}
6446
6447static int ftrace_cmp_ips(const void *a, const void *b)
6448{
6449	const unsigned long *ipa = a;
6450	const unsigned long *ipb = b;
6451
6452	if (*ipa > *ipb)
6453		return 1;
6454	if (*ipa < *ipb)
6455		return -1;
6456	return 0;
6457}
6458
6459#ifdef CONFIG_FTRACE_SORT_STARTUP_TEST
6460static void test_is_sorted(unsigned long *start, unsigned long count)
6461{
6462	int i;
6463
6464	for (i = 1; i < count; i++) {
6465		if (WARN(start[i - 1] > start[i],
6466			 "[%d] %pS at %lx is not sorted with %pS at %lx\n", i,
6467			 (void *)start[i - 1], start[i - 1],
6468			 (void *)start[i], start[i]))
6469			break;
6470	}
6471	if (i == count)
6472		pr_info("ftrace section at %px sorted properly\n", start);
6473}
6474#else
6475static void test_is_sorted(unsigned long *start, unsigned long count)
6476{
6477}
6478#endif
6479
6480static int ftrace_process_locs(struct module *mod,
6481			       unsigned long *start,
6482			       unsigned long *end)
6483{
6484	struct ftrace_page *pg_unuse = NULL;
6485	struct ftrace_page *start_pg;
6486	struct ftrace_page *pg;
6487	struct dyn_ftrace *rec;
6488	unsigned long skipped = 0;
6489	unsigned long count;
6490	unsigned long *p;
6491	unsigned long addr;
6492	unsigned long flags = 0; /* Shut up gcc */
6493	int ret = -ENOMEM;
6494
6495	count = end - start;
6496
6497	if (!count)
6498		return 0;
6499
6500	/*
6501	 * Sorting mcount in vmlinux at build time depend on
6502	 * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in
6503	 * modules can not be sorted at build time.
6504	 */
6505	if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
6506		sort(start, count, sizeof(*start),
6507		     ftrace_cmp_ips, NULL);
6508	} else {
6509		test_is_sorted(start, count);
6510	}
6511
6512	start_pg = ftrace_allocate_pages(count);
6513	if (!start_pg)
6514		return -ENOMEM;
6515
6516	mutex_lock(&ftrace_lock);
6517
6518	/*
6519	 * Core and each module needs their own pages, as
6520	 * modules will free them when they are removed.
6521	 * Force a new page to be allocated for modules.
6522	 */
6523	if (!mod) {
6524		WARN_ON(ftrace_pages || ftrace_pages_start);
6525		/* First initialization */
6526		ftrace_pages = ftrace_pages_start = start_pg;
6527	} else {
6528		if (!ftrace_pages)
6529			goto out;
6530
6531		if (WARN_ON(ftrace_pages->next)) {
6532			/* Hmm, we have free pages? */
6533			while (ftrace_pages->next)
6534				ftrace_pages = ftrace_pages->next;
6535		}
6536
6537		ftrace_pages->next = start_pg;
6538	}
6539
6540	p = start;
6541	pg = start_pg;
6542	while (p < end) {
6543		unsigned long end_offset;
6544		addr = ftrace_call_adjust(*p++);
6545		/*
6546		 * Some architecture linkers will pad between
6547		 * the different mcount_loc sections of different
6548		 * object files to satisfy alignments.
6549		 * Skip any NULL pointers.
6550		 */
6551		if (!addr) {
6552			skipped++;
6553			continue;
6554		}
6555
6556		end_offset = (pg->index+1) * sizeof(pg->records[0]);
6557		if (end_offset > PAGE_SIZE << pg->order) {
6558			/* We should have allocated enough */
6559			if (WARN_ON(!pg->next))
6560				break;
6561			pg = pg->next;
6562		}
6563
6564		rec = &pg->records[pg->index++];
6565		rec->ip = addr;
6566	}
6567
6568	if (pg->next) {
6569		pg_unuse = pg->next;
6570		pg->next = NULL;
6571	}
6572
6573	/* Assign the last page to ftrace_pages */
6574	ftrace_pages = pg;
6575
6576	/*
6577	 * We only need to disable interrupts on start up
6578	 * because we are modifying code that an interrupt
6579	 * may execute, and the modification is not atomic.
6580	 * But for modules, nothing runs the code we modify
6581	 * until we are finished with it, and there's no
6582	 * reason to cause large interrupt latencies while we do it.
6583	 */
6584	if (!mod)
6585		local_irq_save(flags);
6586	ftrace_update_code(mod, start_pg);
6587	if (!mod)
6588		local_irq_restore(flags);
6589	ret = 0;
6590 out:
6591	mutex_unlock(&ftrace_lock);
6592
6593	/* We should have used all pages unless we skipped some */
6594	if (pg_unuse) {
6595		WARN_ON(!skipped);
6596		ftrace_free_pages(pg_unuse);
6597	}
6598	return ret;
6599}
6600
6601struct ftrace_mod_func {
6602	struct list_head	list;
6603	char			*name;
6604	unsigned long		ip;
6605	unsigned int		size;
6606};
6607
6608struct ftrace_mod_map {
6609	struct rcu_head		rcu;
6610	struct list_head	list;
6611	struct module		*mod;
6612	unsigned long		start_addr;
6613	unsigned long		end_addr;
6614	struct list_head	funcs;
6615	unsigned int		num_funcs;
6616};
6617
6618static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6619					 unsigned long *value, char *type,
6620					 char *name, char *module_name,
6621					 int *exported)
6622{
6623	struct ftrace_ops *op;
6624
6625	list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6626		if (!op->trampoline || symnum--)
6627			continue;
6628		*value = op->trampoline;
6629		*type = 't';
6630		strscpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6631		strscpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6632		*exported = 0;
6633		return 0;
6634	}
6635
6636	return -ERANGE;
6637}
6638
6639#if defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) || defined(CONFIG_MODULES)
6640/*
6641 * Check if the current ops references the given ip.
6642 *
6643 * If the ops traces all functions, then it was already accounted for.
6644 * If the ops does not trace the current record function, skip it.
6645 * If the ops ignores the function via notrace filter, skip it.
6646 */
6647static bool
6648ops_references_ip(struct ftrace_ops *ops, unsigned long ip)
6649{
6650	/* If ops isn't enabled, ignore it */
6651	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
6652		return false;
6653
6654	/* If ops traces all then it includes this function */
6655	if (ops_traces_mod(ops))
6656		return true;
6657
6658	/* The function must be in the filter */
6659	if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
6660	    !__ftrace_lookup_ip(ops->func_hash->filter_hash, ip))
6661		return false;
6662
6663	/* If in notrace hash, we ignore it too */
6664	if (ftrace_lookup_ip(ops->func_hash->notrace_hash, ip))
6665		return false;
6666
6667	return true;
6668}
6669#endif
6670
6671#ifdef CONFIG_MODULES
6672
6673#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6674
6675static LIST_HEAD(ftrace_mod_maps);
6676
6677static int referenced_filters(struct dyn_ftrace *rec)
6678{
6679	struct ftrace_ops *ops;
6680	int cnt = 0;
6681
6682	for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6683		if (ops_references_ip(ops, rec->ip)) {
6684			if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6685				continue;
6686			if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6687				continue;
6688			cnt++;
6689			if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6690				rec->flags |= FTRACE_FL_REGS;
6691			if (cnt == 1 && ops->trampoline)
6692				rec->flags |= FTRACE_FL_TRAMP;
6693			else
6694				rec->flags &= ~FTRACE_FL_TRAMP;
6695		}
6696	}
6697
6698	return cnt;
6699}
6700
6701static void
6702clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6703{
6704	struct ftrace_func_entry *entry;
6705	struct dyn_ftrace *rec;
6706	int i;
6707
6708	if (ftrace_hash_empty(hash))
6709		return;
6710
6711	for (i = 0; i < pg->index; i++) {
6712		rec = &pg->records[i];
6713		entry = __ftrace_lookup_ip(hash, rec->ip);
6714		/*
6715		 * Do not allow this rec to match again.
6716		 * Yeah, it may waste some memory, but will be removed
6717		 * if/when the hash is modified again.
6718		 */
6719		if (entry)
6720			entry->ip = 0;
6721	}
6722}
6723
6724/* Clear any records from hashes */
6725static void clear_mod_from_hashes(struct ftrace_page *pg)
6726{
6727	struct trace_array *tr;
6728
6729	mutex_lock(&trace_types_lock);
6730	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6731		if (!tr->ops || !tr->ops->func_hash)
6732			continue;
6733		mutex_lock(&tr->ops->func_hash->regex_lock);
6734		clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6735		clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6736		mutex_unlock(&tr->ops->func_hash->regex_lock);
6737	}
6738	mutex_unlock(&trace_types_lock);
6739}
6740
6741static void ftrace_free_mod_map(struct rcu_head *rcu)
6742{
6743	struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6744	struct ftrace_mod_func *mod_func;
6745	struct ftrace_mod_func *n;
6746
6747	/* All the contents of mod_map are now not visible to readers */
6748	list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6749		kfree(mod_func->name);
6750		list_del(&mod_func->list);
6751		kfree(mod_func);
6752	}
6753
6754	kfree(mod_map);
6755}
6756
6757void ftrace_release_mod(struct module *mod)
6758{
6759	struct ftrace_mod_map *mod_map;
6760	struct ftrace_mod_map *n;
6761	struct dyn_ftrace *rec;
6762	struct ftrace_page **last_pg;
6763	struct ftrace_page *tmp_page = NULL;
6764	struct ftrace_page *pg;
6765
6766	mutex_lock(&ftrace_lock);
6767
6768	if (ftrace_disabled)
6769		goto out_unlock;
6770
6771	list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6772		if (mod_map->mod == mod) {
6773			list_del_rcu(&mod_map->list);
6774			call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6775			break;
6776		}
6777	}
6778
6779	/*
6780	 * Each module has its own ftrace_pages, remove
6781	 * them from the list.
6782	 */
6783	last_pg = &ftrace_pages_start;
6784	for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6785		rec = &pg->records[0];
6786		if (within_module(rec->ip, mod)) {
 
6787			/*
6788			 * As core pages are first, the first
6789			 * page should never be a module page.
6790			 */
6791			if (WARN_ON(pg == ftrace_pages_start))
6792				goto out_unlock;
6793
6794			/* Check if we are deleting the last page */
6795			if (pg == ftrace_pages)
6796				ftrace_pages = next_to_ftrace_page(last_pg);
6797
6798			ftrace_update_tot_cnt -= pg->index;
6799			*last_pg = pg->next;
6800
6801			pg->next = tmp_page;
6802			tmp_page = pg;
6803		} else
6804			last_pg = &pg->next;
6805	}
6806 out_unlock:
6807	mutex_unlock(&ftrace_lock);
6808
6809	for (pg = tmp_page; pg; pg = tmp_page) {
6810
6811		/* Needs to be called outside of ftrace_lock */
6812		clear_mod_from_hashes(pg);
6813
6814		if (pg->records) {
6815			free_pages((unsigned long)pg->records, pg->order);
6816			ftrace_number_of_pages -= 1 << pg->order;
6817		}
6818		tmp_page = pg->next;
6819		kfree(pg);
6820		ftrace_number_of_groups--;
6821	}
6822}
6823
6824void ftrace_module_enable(struct module *mod)
6825{
6826	struct dyn_ftrace *rec;
6827	struct ftrace_page *pg;
6828
6829	mutex_lock(&ftrace_lock);
6830
6831	if (ftrace_disabled)
6832		goto out_unlock;
6833
6834	/*
6835	 * If the tracing is enabled, go ahead and enable the record.
6836	 *
6837	 * The reason not to enable the record immediately is the
6838	 * inherent check of ftrace_make_nop/ftrace_make_call for
6839	 * correct previous instructions.  Making first the NOP
6840	 * conversion puts the module to the correct state, thus
6841	 * passing the ftrace_make_call check.
6842	 *
6843	 * We also delay this to after the module code already set the
6844	 * text to read-only, as we now need to set it back to read-write
6845	 * so that we can modify the text.
6846	 */
6847	if (ftrace_start_up)
6848		ftrace_arch_code_modify_prepare();
6849
6850	do_for_each_ftrace_rec(pg, rec) {
6851		int cnt;
6852		/*
6853		 * do_for_each_ftrace_rec() is a double loop.
6854		 * module text shares the pg. If a record is
6855		 * not part of this module, then skip this pg,
6856		 * which the "break" will do.
6857		 */
6858		if (!within_module(rec->ip, mod))
 
6859			break;
6860
6861		/* Weak functions should still be ignored */
6862		if (!test_for_valid_rec(rec)) {
6863			/* Clear all other flags. Should not be enabled anyway */
6864			rec->flags = FTRACE_FL_DISABLED;
6865			continue;
6866		}
6867
6868		cnt = 0;
6869
6870		/*
6871		 * When adding a module, we need to check if tracers are
6872		 * currently enabled and if they are, and can trace this record,
6873		 * we need to enable the module functions as well as update the
6874		 * reference counts for those function records.
6875		 */
6876		if (ftrace_start_up)
6877			cnt += referenced_filters(rec);
6878
6879		rec->flags &= ~FTRACE_FL_DISABLED;
6880		rec->flags += cnt;
6881
6882		if (ftrace_start_up && cnt) {
6883			int failed = __ftrace_replace_code(rec, 1);
6884			if (failed) {
6885				ftrace_bug(failed, rec);
6886				goto out_loop;
6887			}
6888		}
6889
6890	} while_for_each_ftrace_rec();
6891
6892 out_loop:
6893	if (ftrace_start_up)
6894		ftrace_arch_code_modify_post_process();
6895
6896 out_unlock:
6897	mutex_unlock(&ftrace_lock);
6898
6899	process_cached_mods(mod->name);
6900}
6901
6902void ftrace_module_init(struct module *mod)
6903{
6904	int ret;
6905
6906	if (ftrace_disabled || !mod->num_ftrace_callsites)
6907		return;
6908
6909	ret = ftrace_process_locs(mod, mod->ftrace_callsites,
6910				  mod->ftrace_callsites + mod->num_ftrace_callsites);
6911	if (ret)
6912		pr_warn("ftrace: failed to allocate entries for module '%s' functions\n",
6913			mod->name);
6914}
6915
6916static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6917				struct dyn_ftrace *rec)
6918{
6919	struct ftrace_mod_func *mod_func;
6920	unsigned long symsize;
6921	unsigned long offset;
6922	char str[KSYM_SYMBOL_LEN];
6923	char *modname;
6924	const char *ret;
6925
6926	ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6927	if (!ret)
6928		return;
6929
6930	mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6931	if (!mod_func)
6932		return;
6933
6934	mod_func->name = kstrdup(str, GFP_KERNEL);
6935	if (!mod_func->name) {
6936		kfree(mod_func);
6937		return;
6938	}
6939
6940	mod_func->ip = rec->ip - offset;
6941	mod_func->size = symsize;
6942
6943	mod_map->num_funcs++;
6944
6945	list_add_rcu(&mod_func->list, &mod_map->funcs);
6946}
6947
6948static struct ftrace_mod_map *
6949allocate_ftrace_mod_map(struct module *mod,
6950			unsigned long start, unsigned long end)
6951{
6952	struct ftrace_mod_map *mod_map;
6953
6954	mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
6955	if (!mod_map)
6956		return NULL;
6957
6958	mod_map->mod = mod;
6959	mod_map->start_addr = start;
6960	mod_map->end_addr = end;
6961	mod_map->num_funcs = 0;
6962
6963	INIT_LIST_HEAD_RCU(&mod_map->funcs);
6964
6965	list_add_rcu(&mod_map->list, &ftrace_mod_maps);
6966
6967	return mod_map;
6968}
6969
6970static const char *
6971ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
6972			   unsigned long addr, unsigned long *size,
6973			   unsigned long *off, char *sym)
6974{
6975	struct ftrace_mod_func *found_func =  NULL;
6976	struct ftrace_mod_func *mod_func;
6977
6978	list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6979		if (addr >= mod_func->ip &&
6980		    addr < mod_func->ip + mod_func->size) {
6981			found_func = mod_func;
6982			break;
6983		}
6984	}
6985
6986	if (found_func) {
6987		if (size)
6988			*size = found_func->size;
6989		if (off)
6990			*off = addr - found_func->ip;
6991		if (sym)
6992			strscpy(sym, found_func->name, KSYM_NAME_LEN);
6993
6994		return found_func->name;
6995	}
6996
6997	return NULL;
6998}
6999
7000const char *
7001ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
7002		   unsigned long *off, char **modname, char *sym)
7003{
7004	struct ftrace_mod_map *mod_map;
7005	const char *ret = NULL;
7006
7007	/* mod_map is freed via call_rcu() */
7008	preempt_disable();
7009	list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7010		ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
7011		if (ret) {
7012			if (modname)
7013				*modname = mod_map->mod->name;
7014			break;
7015		}
7016	}
7017	preempt_enable();
7018
7019	return ret;
7020}
7021
7022int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7023			   char *type, char *name,
7024			   char *module_name, int *exported)
7025{
7026	struct ftrace_mod_map *mod_map;
7027	struct ftrace_mod_func *mod_func;
7028	int ret;
7029
7030	preempt_disable();
7031	list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7032
7033		if (symnum >= mod_map->num_funcs) {
7034			symnum -= mod_map->num_funcs;
7035			continue;
7036		}
7037
7038		list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7039			if (symnum > 1) {
7040				symnum--;
7041				continue;
7042			}
7043
7044			*value = mod_func->ip;
7045			*type = 'T';
7046			strscpy(name, mod_func->name, KSYM_NAME_LEN);
7047			strscpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
7048			*exported = 1;
7049			preempt_enable();
7050			return 0;
7051		}
7052		WARN_ON(1);
7053		break;
7054	}
7055	ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7056					    module_name, exported);
7057	preempt_enable();
7058	return ret;
7059}
7060
7061#else
7062static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7063				struct dyn_ftrace *rec) { }
7064static inline struct ftrace_mod_map *
7065allocate_ftrace_mod_map(struct module *mod,
7066			unsigned long start, unsigned long end)
7067{
7068	return NULL;
7069}
7070int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7071			   char *type, char *name, char *module_name,
7072			   int *exported)
7073{
7074	int ret;
7075
7076	preempt_disable();
7077	ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7078					    module_name, exported);
7079	preempt_enable();
7080	return ret;
7081}
7082#endif /* CONFIG_MODULES */
7083
7084struct ftrace_init_func {
7085	struct list_head list;
7086	unsigned long ip;
7087};
7088
7089/* Clear any init ips from hashes */
7090static void
7091clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
7092{
7093	struct ftrace_func_entry *entry;
7094
7095	entry = ftrace_lookup_ip(hash, func->ip);
7096	/*
7097	 * Do not allow this rec to match again.
7098	 * Yeah, it may waste some memory, but will be removed
7099	 * if/when the hash is modified again.
7100	 */
7101	if (entry)
7102		entry->ip = 0;
7103}
7104
7105static void
7106clear_func_from_hashes(struct ftrace_init_func *func)
7107{
7108	struct trace_array *tr;
7109
7110	mutex_lock(&trace_types_lock);
7111	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7112		if (!tr->ops || !tr->ops->func_hash)
7113			continue;
7114		mutex_lock(&tr->ops->func_hash->regex_lock);
7115		clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
7116		clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
7117		mutex_unlock(&tr->ops->func_hash->regex_lock);
7118	}
7119	mutex_unlock(&trace_types_lock);
7120}
7121
7122static void add_to_clear_hash_list(struct list_head *clear_list,
7123				   struct dyn_ftrace *rec)
7124{
7125	struct ftrace_init_func *func;
7126
7127	func = kmalloc(sizeof(*func), GFP_KERNEL);
7128	if (!func) {
7129		MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
7130		return;
7131	}
7132
7133	func->ip = rec->ip;
7134	list_add(&func->list, clear_list);
7135}
7136
7137void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
7138{
7139	unsigned long start = (unsigned long)(start_ptr);
7140	unsigned long end = (unsigned long)(end_ptr);
7141	struct ftrace_page **last_pg = &ftrace_pages_start;
7142	struct ftrace_page *pg;
7143	struct dyn_ftrace *rec;
7144	struct dyn_ftrace key;
7145	struct ftrace_mod_map *mod_map = NULL;
7146	struct ftrace_init_func *func, *func_next;
7147	LIST_HEAD(clear_hash);
 
 
7148
7149	key.ip = start;
7150	key.flags = end;	/* overload flags, as it is unsigned long */
7151
7152	mutex_lock(&ftrace_lock);
7153
7154	/*
7155	 * If we are freeing module init memory, then check if
7156	 * any tracer is active. If so, we need to save a mapping of
7157	 * the module functions being freed with the address.
7158	 */
7159	if (mod && ftrace_ops_list != &ftrace_list_end)
7160		mod_map = allocate_ftrace_mod_map(mod, start, end);
7161
7162	for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
7163		if (end < pg->records[0].ip ||
7164		    start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
7165			continue;
7166 again:
7167		rec = bsearch(&key, pg->records, pg->index,
7168			      sizeof(struct dyn_ftrace),
7169			      ftrace_cmp_recs);
7170		if (!rec)
7171			continue;
7172
7173		/* rec will be cleared from hashes after ftrace_lock unlock */
7174		add_to_clear_hash_list(&clear_hash, rec);
7175
7176		if (mod_map)
7177			save_ftrace_mod_rec(mod_map, rec);
7178
7179		pg->index--;
7180		ftrace_update_tot_cnt--;
7181		if (!pg->index) {
7182			*last_pg = pg->next;
7183			if (pg->records) {
7184				free_pages((unsigned long)pg->records, pg->order);
7185				ftrace_number_of_pages -= 1 << pg->order;
7186			}
7187			ftrace_number_of_groups--;
7188			kfree(pg);
7189			pg = container_of(last_pg, struct ftrace_page, next);
7190			if (!(*last_pg))
7191				ftrace_pages = pg;
7192			continue;
7193		}
7194		memmove(rec, rec + 1,
7195			(pg->index - (rec - pg->records)) * sizeof(*rec));
7196		/* More than one function may be in this block */
7197		goto again;
7198	}
7199	mutex_unlock(&ftrace_lock);
7200
7201	list_for_each_entry_safe(func, func_next, &clear_hash, list) {
7202		clear_func_from_hashes(func);
7203		kfree(func);
7204	}
7205}
7206
7207void __init ftrace_free_init_mem(void)
7208{
7209	void *start = (void *)(&__init_begin);
7210	void *end = (void *)(&__init_end);
7211
7212	ftrace_boot_snapshot();
7213
7214	ftrace_free_mem(NULL, start, end);
7215}
7216
7217int __init __weak ftrace_dyn_arch_init(void)
7218{
7219	return 0;
7220}
7221
7222void __init ftrace_init(void)
7223{
7224	extern unsigned long __start_mcount_loc[];
7225	extern unsigned long __stop_mcount_loc[];
7226	unsigned long count, flags;
7227	int ret;
7228
7229	local_irq_save(flags);
7230	ret = ftrace_dyn_arch_init();
7231	local_irq_restore(flags);
7232	if (ret)
7233		goto failed;
7234
7235	count = __stop_mcount_loc - __start_mcount_loc;
7236	if (!count) {
7237		pr_info("ftrace: No functions to be traced?\n");
7238		goto failed;
7239	}
7240
7241	pr_info("ftrace: allocating %ld entries in %ld pages\n",
7242		count, DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
7243
7244	ret = ftrace_process_locs(NULL,
7245				  __start_mcount_loc,
7246				  __stop_mcount_loc);
7247	if (ret) {
7248		pr_warn("ftrace: failed to allocate entries for functions\n");
7249		goto failed;
7250	}
7251
7252	pr_info("ftrace: allocated %ld pages with %ld groups\n",
7253		ftrace_number_of_pages, ftrace_number_of_groups);
7254
7255	last_ftrace_enabled = ftrace_enabled = 1;
7256
7257	set_ftrace_early_filters();
7258
7259	return;
7260 failed:
7261	ftrace_disabled = 1;
7262}
7263
7264/* Do nothing if arch does not support this */
7265void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
7266{
7267}
7268
7269static void ftrace_update_trampoline(struct ftrace_ops *ops)
7270{
7271	unsigned long trampoline = ops->trampoline;
7272
7273	arch_ftrace_update_trampoline(ops);
7274	if (ops->trampoline && ops->trampoline != trampoline &&
7275	    (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
7276		/* Add to kallsyms before the perf events */
7277		ftrace_add_trampoline_to_kallsyms(ops);
7278		perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
7279				   ops->trampoline, ops->trampoline_size, false,
7280				   FTRACE_TRAMPOLINE_SYM);
7281		/*
7282		 * Record the perf text poke event after the ksymbol register
7283		 * event.
7284		 */
7285		perf_event_text_poke((void *)ops->trampoline, NULL, 0,
7286				     (void *)ops->trampoline,
7287				     ops->trampoline_size);
7288	}
7289}
7290
7291void ftrace_init_trace_array(struct trace_array *tr)
7292{
7293	INIT_LIST_HEAD(&tr->func_probes);
7294	INIT_LIST_HEAD(&tr->mod_trace);
7295	INIT_LIST_HEAD(&tr->mod_notrace);
7296}
7297#else
7298
7299struct ftrace_ops global_ops = {
7300	.func			= ftrace_stub,
7301	.flags			= FTRACE_OPS_FL_INITIALIZED |
7302				  FTRACE_OPS_FL_PID,
7303};
7304
7305static int __init ftrace_nodyn_init(void)
7306{
7307	ftrace_enabled = 1;
7308	return 0;
7309}
7310core_initcall(ftrace_nodyn_init);
7311
7312static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
7313static inline void ftrace_startup_all(int command) { }
7314
7315static void ftrace_update_trampoline(struct ftrace_ops *ops)
7316{
7317}
7318
7319#endif /* CONFIG_DYNAMIC_FTRACE */
7320
7321__init void ftrace_init_global_array_ops(struct trace_array *tr)
7322{
7323	tr->ops = &global_ops;
7324	tr->ops->private = tr;
7325	ftrace_init_trace_array(tr);
7326}
7327
7328void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
7329{
7330	/* If we filter on pids, update to use the pid function */
7331	if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
7332		if (WARN_ON(tr->ops->func != ftrace_stub))
7333			printk("ftrace ops had %pS for function\n",
7334			       tr->ops->func);
7335	}
7336	tr->ops->func = func;
7337	tr->ops->private = tr;
7338}
7339
7340void ftrace_reset_array_ops(struct trace_array *tr)
7341{
7342	tr->ops->func = ftrace_stub;
7343}
7344
7345static nokprobe_inline void
7346__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7347		       struct ftrace_ops *ignored, struct ftrace_regs *fregs)
7348{
7349	struct pt_regs *regs = ftrace_get_regs(fregs);
7350	struct ftrace_ops *op;
7351	int bit;
7352
7353	/*
7354	 * The ftrace_test_and_set_recursion() will disable preemption,
7355	 * which is required since some of the ops may be dynamically
7356	 * allocated, they must be freed after a synchronize_rcu().
7357	 */
7358	bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7359	if (bit < 0)
7360		return;
7361
7362	do_for_each_ftrace_op(op, ftrace_ops_list) {
7363		/* Stub functions don't need to be called nor tested */
7364		if (op->flags & FTRACE_OPS_FL_STUB)
7365			continue;
7366		/*
7367		 * Check the following for each ops before calling their func:
7368		 *  if RCU flag is set, then rcu_is_watching() must be true
7369		 *  Otherwise test if the ip matches the ops filter
7370		 *
7371		 * If any of the above fails then the op->func() is not executed.
7372		 */
7373		if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
7374		    ftrace_ops_test(op, ip, regs)) {
7375			if (FTRACE_WARN_ON(!op->func)) {
7376				pr_warn("op=%p %pS\n", op, op);
7377				goto out;
7378			}
7379			op->func(ip, parent_ip, op, fregs);
7380		}
7381	} while_for_each_ftrace_op(op);
7382out:
7383	trace_clear_recursion(bit);
7384}
7385
7386/*
7387 * Some archs only support passing ip and parent_ip. Even though
7388 * the list function ignores the op parameter, we do not want any
7389 * C side effects, where a function is called without the caller
7390 * sending a third parameter.
7391 * Archs are to support both the regs and ftrace_ops at the same time.
7392 * If they support ftrace_ops, it is assumed they support regs.
7393 * If call backs want to use regs, they must either check for regs
7394 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7395 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7396 * An architecture can pass partial regs with ftrace_ops and still
7397 * set the ARCH_SUPPORTS_FTRACE_OPS.
7398 *
7399 * In vmlinux.lds.h, ftrace_ops_list_func() is defined to be
7400 * arch_ftrace_ops_list_func.
7401 */
7402#if ARCH_SUPPORTS_FTRACE_OPS
7403void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7404			       struct ftrace_ops *op, struct ftrace_regs *fregs)
7405{
7406	__ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
7407}
7408#else
7409void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
7410{
7411	__ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7412}
7413#endif
7414NOKPROBE_SYMBOL(arch_ftrace_ops_list_func);
7415
7416/*
7417 * If there's only one function registered but it does not support
7418 * recursion, needs RCU protection, then this function will be called
7419 * by the mcount trampoline.
7420 */
7421static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7422				   struct ftrace_ops *op, struct ftrace_regs *fregs)
7423{
7424	int bit;
7425
7426	bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7427	if (bit < 0)
7428		return;
7429
7430	if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7431		op->func(ip, parent_ip, op, fregs);
7432
7433	trace_clear_recursion(bit);
7434}
7435NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7436
7437/**
7438 * ftrace_ops_get_func - get the function a trampoline should call
7439 * @ops: the ops to get the function for
7440 *
7441 * Normally the mcount trampoline will call the ops->func, but there
7442 * are times that it should not. For example, if the ops does not
7443 * have its own recursion protection, then it should call the
7444 * ftrace_ops_assist_func() instead.
7445 *
7446 * Returns the function that the trampoline should call for @ops.
7447 */
7448ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7449{
7450	/*
7451	 * If the function does not handle recursion or needs to be RCU safe,
7452	 * then we need to call the assist handler.
7453	 */
7454	if (ops->flags & (FTRACE_OPS_FL_RECURSION |
7455			  FTRACE_OPS_FL_RCU))
7456		return ftrace_ops_assist_func;
7457
7458	return ops->func;
7459}
7460
7461static void
7462ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7463				     struct task_struct *prev,
7464				     struct task_struct *next,
7465				     unsigned int prev_state)
7466{
7467	struct trace_array *tr = data;
7468	struct trace_pid_list *pid_list;
7469	struct trace_pid_list *no_pid_list;
7470
7471	pid_list = rcu_dereference_sched(tr->function_pids);
7472	no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7473
7474	if (trace_ignore_this_task(pid_list, no_pid_list, next))
7475		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7476			       FTRACE_PID_IGNORE);
7477	else
7478		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7479			       next->pid);
7480}
7481
7482static void
7483ftrace_pid_follow_sched_process_fork(void *data,
7484				     struct task_struct *self,
7485				     struct task_struct *task)
7486{
7487	struct trace_pid_list *pid_list;
7488	struct trace_array *tr = data;
7489
7490	pid_list = rcu_dereference_sched(tr->function_pids);
7491	trace_filter_add_remove_task(pid_list, self, task);
7492
7493	pid_list = rcu_dereference_sched(tr->function_no_pids);
7494	trace_filter_add_remove_task(pid_list, self, task);
7495}
7496
7497static void
7498ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7499{
7500	struct trace_pid_list *pid_list;
7501	struct trace_array *tr = data;
7502
7503	pid_list = rcu_dereference_sched(tr->function_pids);
7504	trace_filter_add_remove_task(pid_list, NULL, task);
7505
7506	pid_list = rcu_dereference_sched(tr->function_no_pids);
7507	trace_filter_add_remove_task(pid_list, NULL, task);
7508}
7509
7510void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7511{
7512	if (enable) {
7513		register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7514						  tr);
7515		register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7516						  tr);
7517	} else {
7518		unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7519						    tr);
7520		unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7521						    tr);
7522	}
7523}
7524
7525static void clear_ftrace_pids(struct trace_array *tr, int type)
7526{
7527	struct trace_pid_list *pid_list;
7528	struct trace_pid_list *no_pid_list;
7529	int cpu;
7530
7531	pid_list = rcu_dereference_protected(tr->function_pids,
7532					     lockdep_is_held(&ftrace_lock));
7533	no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7534						lockdep_is_held(&ftrace_lock));
7535
7536	/* Make sure there's something to do */
7537	if (!pid_type_enabled(type, pid_list, no_pid_list))
7538		return;
7539
7540	/* See if the pids still need to be checked after this */
7541	if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7542		unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7543		for_each_possible_cpu(cpu)
7544			per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7545	}
7546
7547	if (type & TRACE_PIDS)
7548		rcu_assign_pointer(tr->function_pids, NULL);
7549
7550	if (type & TRACE_NO_PIDS)
7551		rcu_assign_pointer(tr->function_no_pids, NULL);
7552
7553	/* Wait till all users are no longer using pid filtering */
7554	synchronize_rcu();
7555
7556	if ((type & TRACE_PIDS) && pid_list)
7557		trace_pid_list_free(pid_list);
7558
7559	if ((type & TRACE_NO_PIDS) && no_pid_list)
7560		trace_pid_list_free(no_pid_list);
7561}
7562
7563void ftrace_clear_pids(struct trace_array *tr)
7564{
7565	mutex_lock(&ftrace_lock);
7566
7567	clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7568
7569	mutex_unlock(&ftrace_lock);
7570}
7571
7572static void ftrace_pid_reset(struct trace_array *tr, int type)
7573{
7574	mutex_lock(&ftrace_lock);
7575	clear_ftrace_pids(tr, type);
7576
7577	ftrace_update_pid_func();
7578	ftrace_startup_all(0);
7579
7580	mutex_unlock(&ftrace_lock);
7581}
7582
7583/* Greater than any max PID */
7584#define FTRACE_NO_PIDS		(void *)(PID_MAX_LIMIT + 1)
7585
7586static void *fpid_start(struct seq_file *m, loff_t *pos)
7587	__acquires(RCU)
7588{
7589	struct trace_pid_list *pid_list;
7590	struct trace_array *tr = m->private;
7591
7592	mutex_lock(&ftrace_lock);
7593	rcu_read_lock_sched();
7594
7595	pid_list = rcu_dereference_sched(tr->function_pids);
7596
7597	if (!pid_list)
7598		return !(*pos) ? FTRACE_NO_PIDS : NULL;
7599
7600	return trace_pid_start(pid_list, pos);
7601}
7602
7603static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7604{
7605	struct trace_array *tr = m->private;
7606	struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7607
7608	if (v == FTRACE_NO_PIDS) {
7609		(*pos)++;
7610		return NULL;
7611	}
7612	return trace_pid_next(pid_list, v, pos);
7613}
7614
7615static void fpid_stop(struct seq_file *m, void *p)
7616	__releases(RCU)
7617{
7618	rcu_read_unlock_sched();
7619	mutex_unlock(&ftrace_lock);
7620}
7621
7622static int fpid_show(struct seq_file *m, void *v)
7623{
7624	if (v == FTRACE_NO_PIDS) {
7625		seq_puts(m, "no pid\n");
7626		return 0;
7627	}
7628
7629	return trace_pid_show(m, v);
7630}
7631
7632static const struct seq_operations ftrace_pid_sops = {
7633	.start = fpid_start,
7634	.next = fpid_next,
7635	.stop = fpid_stop,
7636	.show = fpid_show,
7637};
7638
7639static void *fnpid_start(struct seq_file *m, loff_t *pos)
7640	__acquires(RCU)
7641{
7642	struct trace_pid_list *pid_list;
7643	struct trace_array *tr = m->private;
7644
7645	mutex_lock(&ftrace_lock);
7646	rcu_read_lock_sched();
7647
7648	pid_list = rcu_dereference_sched(tr->function_no_pids);
7649
7650	if (!pid_list)
7651		return !(*pos) ? FTRACE_NO_PIDS : NULL;
7652
7653	return trace_pid_start(pid_list, pos);
7654}
7655
7656static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7657{
7658	struct trace_array *tr = m->private;
7659	struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7660
7661	if (v == FTRACE_NO_PIDS) {
7662		(*pos)++;
7663		return NULL;
7664	}
7665	return trace_pid_next(pid_list, v, pos);
7666}
7667
7668static const struct seq_operations ftrace_no_pid_sops = {
7669	.start = fnpid_start,
7670	.next = fnpid_next,
7671	.stop = fpid_stop,
7672	.show = fpid_show,
7673};
7674
7675static int pid_open(struct inode *inode, struct file *file, int type)
7676{
7677	const struct seq_operations *seq_ops;
7678	struct trace_array *tr = inode->i_private;
7679	struct seq_file *m;
7680	int ret = 0;
7681
7682	ret = tracing_check_open_get_tr(tr);
7683	if (ret)
7684		return ret;
7685
7686	if ((file->f_mode & FMODE_WRITE) &&
7687	    (file->f_flags & O_TRUNC))
7688		ftrace_pid_reset(tr, type);
7689
7690	switch (type) {
7691	case TRACE_PIDS:
7692		seq_ops = &ftrace_pid_sops;
7693		break;
7694	case TRACE_NO_PIDS:
7695		seq_ops = &ftrace_no_pid_sops;
7696		break;
7697	default:
7698		trace_array_put(tr);
7699		WARN_ON_ONCE(1);
7700		return -EINVAL;
7701	}
7702
7703	ret = seq_open(file, seq_ops);
7704	if (ret < 0) {
7705		trace_array_put(tr);
7706	} else {
7707		m = file->private_data;
7708		/* copy tr over to seq ops */
7709		m->private = tr;
7710	}
7711
7712	return ret;
7713}
7714
7715static int
7716ftrace_pid_open(struct inode *inode, struct file *file)
7717{
7718	return pid_open(inode, file, TRACE_PIDS);
7719}
7720
7721static int
7722ftrace_no_pid_open(struct inode *inode, struct file *file)
7723{
7724	return pid_open(inode, file, TRACE_NO_PIDS);
7725}
7726
7727static void ignore_task_cpu(void *data)
7728{
7729	struct trace_array *tr = data;
7730	struct trace_pid_list *pid_list;
7731	struct trace_pid_list *no_pid_list;
7732
7733	/*
7734	 * This function is called by on_each_cpu() while the
7735	 * event_mutex is held.
7736	 */
7737	pid_list = rcu_dereference_protected(tr->function_pids,
7738					     mutex_is_locked(&ftrace_lock));
7739	no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7740						mutex_is_locked(&ftrace_lock));
7741
7742	if (trace_ignore_this_task(pid_list, no_pid_list, current))
7743		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7744			       FTRACE_PID_IGNORE);
7745	else
7746		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7747			       current->pid);
7748}
7749
7750static ssize_t
7751pid_write(struct file *filp, const char __user *ubuf,
7752	  size_t cnt, loff_t *ppos, int type)
7753{
7754	struct seq_file *m = filp->private_data;
7755	struct trace_array *tr = m->private;
7756	struct trace_pid_list *filtered_pids;
7757	struct trace_pid_list *other_pids;
7758	struct trace_pid_list *pid_list;
7759	ssize_t ret;
7760
7761	if (!cnt)
7762		return 0;
7763
7764	mutex_lock(&ftrace_lock);
7765
7766	switch (type) {
7767	case TRACE_PIDS:
7768		filtered_pids = rcu_dereference_protected(tr->function_pids,
7769					     lockdep_is_held(&ftrace_lock));
7770		other_pids = rcu_dereference_protected(tr->function_no_pids,
7771					     lockdep_is_held(&ftrace_lock));
7772		break;
7773	case TRACE_NO_PIDS:
7774		filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7775					     lockdep_is_held(&ftrace_lock));
7776		other_pids = rcu_dereference_protected(tr->function_pids,
7777					     lockdep_is_held(&ftrace_lock));
7778		break;
7779	default:
7780		ret = -EINVAL;
7781		WARN_ON_ONCE(1);
7782		goto out;
7783	}
7784
7785	ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7786	if (ret < 0)
7787		goto out;
7788
7789	switch (type) {
7790	case TRACE_PIDS:
7791		rcu_assign_pointer(tr->function_pids, pid_list);
7792		break;
7793	case TRACE_NO_PIDS:
7794		rcu_assign_pointer(tr->function_no_pids, pid_list);
7795		break;
7796	}
7797
7798
7799	if (filtered_pids) {
7800		synchronize_rcu();
7801		trace_pid_list_free(filtered_pids);
7802	} else if (pid_list && !other_pids) {
7803		/* Register a probe to set whether to ignore the tracing of a task */
7804		register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7805	}
7806
7807	/*
7808	 * Ignoring of pids is done at task switch. But we have to
7809	 * check for those tasks that are currently running.
7810	 * Always do this in case a pid was appended or removed.
7811	 */
7812	on_each_cpu(ignore_task_cpu, tr, 1);
7813
7814	ftrace_update_pid_func();
7815	ftrace_startup_all(0);
7816 out:
7817	mutex_unlock(&ftrace_lock);
7818
7819	if (ret > 0)
7820		*ppos += ret;
7821
7822	return ret;
7823}
7824
7825static ssize_t
7826ftrace_pid_write(struct file *filp, const char __user *ubuf,
7827		 size_t cnt, loff_t *ppos)
7828{
7829	return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7830}
7831
7832static ssize_t
7833ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7834		    size_t cnt, loff_t *ppos)
7835{
7836	return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7837}
7838
7839static int
7840ftrace_pid_release(struct inode *inode, struct file *file)
7841{
7842	struct trace_array *tr = inode->i_private;
7843
7844	trace_array_put(tr);
7845
7846	return seq_release(inode, file);
7847}
7848
7849static const struct file_operations ftrace_pid_fops = {
7850	.open		= ftrace_pid_open,
7851	.write		= ftrace_pid_write,
7852	.read		= seq_read,
7853	.llseek		= tracing_lseek,
7854	.release	= ftrace_pid_release,
7855};
7856
7857static const struct file_operations ftrace_no_pid_fops = {
7858	.open		= ftrace_no_pid_open,
7859	.write		= ftrace_no_pid_write,
7860	.read		= seq_read,
7861	.llseek		= tracing_lseek,
7862	.release	= ftrace_pid_release,
7863};
7864
7865void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7866{
7867	trace_create_file("set_ftrace_pid", TRACE_MODE_WRITE, d_tracer,
7868			    tr, &ftrace_pid_fops);
7869	trace_create_file("set_ftrace_notrace_pid", TRACE_MODE_WRITE,
7870			  d_tracer, tr, &ftrace_no_pid_fops);
7871}
7872
7873void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
7874					 struct dentry *d_tracer)
7875{
7876	/* Only the top level directory has the dyn_tracefs and profile */
7877	WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
7878
7879	ftrace_init_dyn_tracefs(d_tracer);
7880	ftrace_profile_tracefs(d_tracer);
7881}
7882
7883/**
7884 * ftrace_kill - kill ftrace
7885 *
7886 * This function should be used by panic code. It stops ftrace
7887 * but in a not so nice way. If you need to simply kill ftrace
7888 * from a non-atomic section, use ftrace_kill.
7889 */
7890void ftrace_kill(void)
7891{
7892	ftrace_disabled = 1;
7893	ftrace_enabled = 0;
7894	ftrace_trace_function = ftrace_stub;
7895}
7896
7897/**
7898 * ftrace_is_dead - Test if ftrace is dead or not.
7899 *
7900 * Returns 1 if ftrace is "dead", zero otherwise.
7901 */
7902int ftrace_is_dead(void)
7903{
7904	return ftrace_disabled;
7905}
7906
7907#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
7908/*
7909 * When registering ftrace_ops with IPMODIFY, it is necessary to make sure
7910 * it doesn't conflict with any direct ftrace_ops. If there is existing
7911 * direct ftrace_ops on a kernel function being patched, call
7912 * FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER on it to enable sharing.
7913 *
7914 * @ops:     ftrace_ops being registered.
7915 *
7916 * Returns:
7917 *         0 on success;
7918 *         Negative on failure.
7919 */
7920static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
7921{
7922	struct ftrace_func_entry *entry;
7923	struct ftrace_hash *hash;
7924	struct ftrace_ops *op;
7925	int size, i, ret;
7926
7927	lockdep_assert_held_once(&direct_mutex);
7928
7929	if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
7930		return 0;
7931
7932	hash = ops->func_hash->filter_hash;
7933	size = 1 << hash->size_bits;
7934	for (i = 0; i < size; i++) {
7935		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
7936			unsigned long ip = entry->ip;
7937			bool found_op = false;
7938
7939			mutex_lock(&ftrace_lock);
7940			do_for_each_ftrace_op(op, ftrace_ops_list) {
7941				if (!(op->flags & FTRACE_OPS_FL_DIRECT))
7942					continue;
7943				if (ops_references_ip(op, ip)) {
7944					found_op = true;
7945					break;
7946				}
7947			} while_for_each_ftrace_op(op);
7948			mutex_unlock(&ftrace_lock);
7949
7950			if (found_op) {
7951				if (!op->ops_func)
7952					return -EBUSY;
7953
7954				ret = op->ops_func(op, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER);
7955				if (ret)
7956					return ret;
7957			}
7958		}
7959	}
7960
7961	return 0;
7962}
7963
7964/*
7965 * Similar to prepare_direct_functions_for_ipmodify, clean up after ops
7966 * with IPMODIFY is unregistered. The cleanup is optional for most DIRECT
7967 * ops.
7968 */
7969static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
7970{
7971	struct ftrace_func_entry *entry;
7972	struct ftrace_hash *hash;
7973	struct ftrace_ops *op;
7974	int size, i;
7975
7976	if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
7977		return;
7978
7979	mutex_lock(&direct_mutex);
7980
7981	hash = ops->func_hash->filter_hash;
7982	size = 1 << hash->size_bits;
7983	for (i = 0; i < size; i++) {
7984		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
7985			unsigned long ip = entry->ip;
7986			bool found_op = false;
7987
7988			mutex_lock(&ftrace_lock);
7989			do_for_each_ftrace_op(op, ftrace_ops_list) {
7990				if (!(op->flags & FTRACE_OPS_FL_DIRECT))
7991					continue;
7992				if (ops_references_ip(op, ip)) {
7993					found_op = true;
7994					break;
7995				}
7996			} while_for_each_ftrace_op(op);
7997			mutex_unlock(&ftrace_lock);
7998
7999			/* The cleanup is optional, ignore any errors */
8000			if (found_op && op->ops_func)
8001				op->ops_func(op, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER);
8002		}
8003	}
8004	mutex_unlock(&direct_mutex);
8005}
8006
8007#define lock_direct_mutex()	mutex_lock(&direct_mutex)
8008#define unlock_direct_mutex()	mutex_unlock(&direct_mutex)
8009
8010#else  /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8011
8012static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
8013{
8014	return 0;
8015}
8016
8017static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
8018{
8019}
8020
8021#define lock_direct_mutex()	do { } while (0)
8022#define unlock_direct_mutex()	do { } while (0)
8023
8024#endif  /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8025
8026/*
8027 * Similar to register_ftrace_function, except we don't lock direct_mutex.
8028 */
8029static int register_ftrace_function_nolock(struct ftrace_ops *ops)
8030{
8031	int ret;
8032
8033	ftrace_ops_init(ops);
8034
8035	mutex_lock(&ftrace_lock);
8036
8037	ret = ftrace_startup(ops, 0);
8038
8039	mutex_unlock(&ftrace_lock);
8040
8041	return ret;
8042}
8043
8044/**
8045 * register_ftrace_function - register a function for profiling
8046 * @ops:	ops structure that holds the function for profiling.
8047 *
8048 * Register a function to be called by all functions in the
8049 * kernel.
8050 *
8051 * Note: @ops->func and all the functions it calls must be labeled
8052 *       with "notrace", otherwise it will go into a
8053 *       recursive loop.
8054 */
8055int register_ftrace_function(struct ftrace_ops *ops)
8056{
8057	int ret;
8058
8059	lock_direct_mutex();
8060	ret = prepare_direct_functions_for_ipmodify(ops);
8061	if (ret < 0)
8062		goto out_unlock;
8063
8064	ret = register_ftrace_function_nolock(ops);
8065
8066out_unlock:
8067	unlock_direct_mutex();
8068	return ret;
8069}
8070EXPORT_SYMBOL_GPL(register_ftrace_function);
8071
8072/**
8073 * unregister_ftrace_function - unregister a function for profiling.
8074 * @ops:	ops structure that holds the function to unregister
8075 *
8076 * Unregister a function that was added to be called by ftrace profiling.
8077 */
8078int unregister_ftrace_function(struct ftrace_ops *ops)
8079{
8080	int ret;
8081
8082	mutex_lock(&ftrace_lock);
8083	ret = ftrace_shutdown(ops, 0);
8084	mutex_unlock(&ftrace_lock);
8085
8086	cleanup_direct_functions_after_ipmodify(ops);
8087	return ret;
8088}
8089EXPORT_SYMBOL_GPL(unregister_ftrace_function);
8090
8091static int symbols_cmp(const void *a, const void *b)
8092{
8093	const char **str_a = (const char **) a;
8094	const char **str_b = (const char **) b;
8095
8096	return strcmp(*str_a, *str_b);
8097}
8098
8099struct kallsyms_data {
8100	unsigned long *addrs;
8101	const char **syms;
8102	size_t cnt;
8103	size_t found;
8104};
8105
8106/* This function gets called for all kernel and module symbols
8107 * and returns 1 in case we resolved all the requested symbols,
8108 * 0 otherwise.
8109 */
8110static int kallsyms_callback(void *data, const char *name, unsigned long addr)
 
8111{
8112	struct kallsyms_data *args = data;
8113	const char **sym;
8114	int idx;
8115
8116	sym = bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp);
8117	if (!sym)
8118		return 0;
8119
8120	idx = sym - args->syms;
8121	if (args->addrs[idx])
8122		return 0;
8123
8124	if (!ftrace_location(addr))
8125		return 0;
8126
8127	args->addrs[idx] = addr;
8128	args->found++;
8129	return args->found == args->cnt ? 1 : 0;
8130}
8131
8132/**
8133 * ftrace_lookup_symbols - Lookup addresses for array of symbols
8134 *
8135 * @sorted_syms: array of symbols pointers symbols to resolve,
8136 * must be alphabetically sorted
8137 * @cnt: number of symbols/addresses in @syms/@addrs arrays
8138 * @addrs: array for storing resulting addresses
8139 *
8140 * This function looks up addresses for array of symbols provided in
8141 * @syms array (must be alphabetically sorted) and stores them in
8142 * @addrs array, which needs to be big enough to store at least @cnt
8143 * addresses.
8144 *
8145 * This function returns 0 if all provided symbols are found,
8146 * -ESRCH otherwise.
8147 */
8148int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
8149{
8150	struct kallsyms_data args;
8151	int found_all;
8152
8153	memset(addrs, 0, sizeof(*addrs) * cnt);
8154	args.addrs = addrs;
8155	args.syms = sorted_syms;
8156	args.cnt = cnt;
8157	args.found = 0;
8158
8159	found_all = kallsyms_on_each_symbol(kallsyms_callback, &args);
8160	if (found_all)
8161		return 0;
8162	found_all = module_kallsyms_on_each_symbol(NULL, kallsyms_callback, &args);
8163	return found_all ? 0 : -ESRCH;
8164}
8165
8166#ifdef CONFIG_SYSCTL
8167
8168#ifdef CONFIG_DYNAMIC_FTRACE
8169static void ftrace_startup_sysctl(void)
8170{
8171	int command;
8172
8173	if (unlikely(ftrace_disabled))
8174		return;
8175
8176	/* Force update next time */
8177	saved_ftrace_func = NULL;
8178	/* ftrace_start_up is true if we want ftrace running */
8179	if (ftrace_start_up) {
8180		command = FTRACE_UPDATE_CALLS;
8181		if (ftrace_graph_active)
8182			command |= FTRACE_START_FUNC_RET;
8183		ftrace_startup_enable(command);
8184	}
8185}
8186
8187static void ftrace_shutdown_sysctl(void)
8188{
8189	int command;
8190
8191	if (unlikely(ftrace_disabled))
8192		return;
8193
8194	/* ftrace_start_up is true if ftrace is running */
8195	if (ftrace_start_up) {
8196		command = FTRACE_DISABLE_CALLS;
8197		if (ftrace_graph_active)
8198			command |= FTRACE_STOP_FUNC_RET;
8199		ftrace_run_update_code(command);
8200	}
8201}
8202#else
8203# define ftrace_startup_sysctl()       do { } while (0)
8204# define ftrace_shutdown_sysctl()      do { } while (0)
8205#endif /* CONFIG_DYNAMIC_FTRACE */
8206
8207static bool is_permanent_ops_registered(void)
8208{
8209	struct ftrace_ops *op;
8210
8211	do_for_each_ftrace_op(op, ftrace_ops_list) {
8212		if (op->flags & FTRACE_OPS_FL_PERMANENT)
8213			return true;
8214	} while_for_each_ftrace_op(op);
8215
8216	return false;
8217}
8218
8219static int
8220ftrace_enable_sysctl(struct ctl_table *table, int write,
8221		     void *buffer, size_t *lenp, loff_t *ppos)
8222{
8223	int ret = -ENODEV;
8224
8225	mutex_lock(&ftrace_lock);
8226
8227	if (unlikely(ftrace_disabled))
8228		goto out;
8229
8230	ret = proc_dointvec(table, write, buffer, lenp, ppos);
8231
8232	if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
8233		goto out;
8234
8235	if (ftrace_enabled) {
8236
8237		/* we are starting ftrace again */
8238		if (rcu_dereference_protected(ftrace_ops_list,
8239			lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
8240			update_ftrace_function();
8241
8242		ftrace_startup_sysctl();
8243
8244	} else {
8245		if (is_permanent_ops_registered()) {
8246			ftrace_enabled = true;
8247			ret = -EBUSY;
8248			goto out;
8249		}
8250
8251		/* stopping ftrace calls (just send to ftrace_stub) */
8252		ftrace_trace_function = ftrace_stub;
8253
8254		ftrace_shutdown_sysctl();
8255	}
8256
8257	last_ftrace_enabled = !!ftrace_enabled;
8258 out:
8259	mutex_unlock(&ftrace_lock);
8260	return ret;
8261}
8262
8263static struct ctl_table ftrace_sysctls[] = {
8264	{
8265		.procname       = "ftrace_enabled",
8266		.data           = &ftrace_enabled,
8267		.maxlen         = sizeof(int),
8268		.mode           = 0644,
8269		.proc_handler   = ftrace_enable_sysctl,
8270	},
8271	{}
8272};
8273
8274static int __init ftrace_sysctl_init(void)
8275{
8276	register_sysctl_init("kernel", ftrace_sysctls);
8277	return 0;
8278}
8279late_initcall(ftrace_sysctl_init);
8280#endif