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	unsigned long ip = 0;
1599
1600	rcu_read_lock();
1601	rec = lookup_rec(start, end);
1602	if (rec)
1603		ip = rec->ip;
1604	rcu_read_unlock();
1605
1606	return ip;
1607}
1608
1609/**
1610 * ftrace_location - return the ftrace location
1611 * @ip: the instruction pointer to check
1612 *
1613 * Returns:
1614 * * If @ip matches the ftrace location, return @ip.
1615 * * If @ip matches sym+0, return sym's ftrace location.
1616 * * Otherwise, return 0.
1617 */
1618unsigned long ftrace_location(unsigned long ip)
1619{
1620	unsigned long loc;
1621	unsigned long offset;
1622	unsigned long size;
1623
1624	loc = ftrace_location_range(ip, ip);
1625	if (!loc) {
1626		if (!kallsyms_lookup_size_offset(ip, &size, &offset))
1627			goto out;
1628
1629		/* map sym+0 to __fentry__ */
1630		if (!offset)
1631			loc = ftrace_location_range(ip, ip + size - 1);
1632	}
1633
 
 
 
1634out:
1635	return loc;
1636}
1637
1638/**
1639 * ftrace_text_reserved - return true if range contains an ftrace location
1640 * @start: start of range to search
1641 * @end: end of range to search (inclusive). @end points to the last byte to check.
1642 *
1643 * Returns: 1 if @start and @end contains a ftrace location.
1644 * That is, the instruction that is either a NOP or call to
1645 * the function tracer. It checks the ftrace internal tables to
1646 * determine if the address belongs or not.
1647 */
1648int ftrace_text_reserved(const void *start, const void *end)
1649{
1650	unsigned long ret;
1651
1652	ret = ftrace_location_range((unsigned long)start,
1653				    (unsigned long)end);
1654
1655	return (int)!!ret;
1656}
1657
1658/* Test if ops registered to this rec needs regs */
1659static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1660{
1661	struct ftrace_ops *ops;
1662	bool keep_regs = false;
1663
1664	for (ops = ftrace_ops_list;
1665	     ops != &ftrace_list_end; ops = ops->next) {
1666		/* pass rec in as regs to have non-NULL val */
1667		if (ftrace_ops_test(ops, rec->ip, rec)) {
1668			if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1669				keep_regs = true;
1670				break;
1671			}
1672		}
1673	}
1674
1675	return  keep_regs;
1676}
1677
1678static struct ftrace_ops *
1679ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1680static struct ftrace_ops *
1681ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1682static struct ftrace_ops *
1683ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1684
1685static bool skip_record(struct dyn_ftrace *rec)
1686{
1687	/*
1688	 * At boot up, weak functions are set to disable. Function tracing
1689	 * can be enabled before they are, and they still need to be disabled now.
1690	 * If the record is disabled, still continue if it is marked as already
1691	 * enabled (this is needed to keep the accounting working).
1692	 */
1693	return rec->flags & FTRACE_FL_DISABLED &&
1694		!(rec->flags & FTRACE_FL_ENABLED);
1695}
1696
1697static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1698				     int filter_hash,
1699				     bool inc)
1700{
1701	struct ftrace_hash *hash;
1702	struct ftrace_hash *other_hash;
1703	struct ftrace_page *pg;
1704	struct dyn_ftrace *rec;
1705	bool update = false;
1706	int count = 0;
1707	int all = false;
1708
1709	/* Only update if the ops has been registered */
1710	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1711		return false;
1712
1713	/*
1714	 * In the filter_hash case:
1715	 *   If the count is zero, we update all records.
1716	 *   Otherwise we just update the items in the hash.
1717	 *
1718	 * In the notrace_hash case:
1719	 *   We enable the update in the hash.
1720	 *   As disabling notrace means enabling the tracing,
1721	 *   and enabling notrace means disabling, the inc variable
1722	 *   gets inversed.
1723	 */
1724	if (filter_hash) {
1725		hash = ops->func_hash->filter_hash;
1726		other_hash = ops->func_hash->notrace_hash;
1727		if (ftrace_hash_empty(hash))
1728			all = true;
1729	} else {
1730		inc = !inc;
1731		hash = ops->func_hash->notrace_hash;
1732		other_hash = ops->func_hash->filter_hash;
1733		/*
1734		 * If the notrace hash has no items,
1735		 * then there's nothing to do.
1736		 */
1737		if (ftrace_hash_empty(hash))
1738			return false;
1739	}
1740
1741	do_for_each_ftrace_rec(pg, rec) {
1742		int in_other_hash = 0;
1743		int in_hash = 0;
1744		int match = 0;
1745
1746		if (skip_record(rec))
1747			continue;
1748
1749		if (all) {
1750			/*
1751			 * Only the filter_hash affects all records.
1752			 * Update if the record is not in the notrace hash.
1753			 */
1754			if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1755				match = 1;
1756		} else {
1757			in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1758			in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1759
1760			/*
1761			 * If filter_hash is set, we want to match all functions
1762			 * that are in the hash but not in the other hash.
1763			 *
1764			 * If filter_hash is not set, then we are decrementing.
1765			 * That means we match anything that is in the hash
1766			 * and also in the other_hash. That is, we need to turn
1767			 * off functions in the other hash because they are disabled
1768			 * by this hash.
1769			 */
1770			if (filter_hash && in_hash && !in_other_hash)
1771				match = 1;
1772			else if (!filter_hash && in_hash &&
1773				 (in_other_hash || ftrace_hash_empty(other_hash)))
1774				match = 1;
1775		}
1776		if (!match)
1777			continue;
1778
1779		if (inc) {
1780			rec->flags++;
1781			if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1782				return false;
1783
1784			if (ops->flags & FTRACE_OPS_FL_DIRECT)
1785				rec->flags |= FTRACE_FL_DIRECT;
1786
1787			/*
1788			 * If there's only a single callback registered to a
1789			 * function, and the ops has a trampoline registered
1790			 * for it, then we can call it directly.
1791			 */
1792			if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1793				rec->flags |= FTRACE_FL_TRAMP;
1794			else
1795				/*
1796				 * If we are adding another function callback
1797				 * to this function, and the previous had a
1798				 * custom trampoline in use, then we need to go
1799				 * back to the default trampoline.
1800				 */
1801				rec->flags &= ~FTRACE_FL_TRAMP;
1802
1803			/*
1804			 * If any ops wants regs saved for this function
1805			 * then all ops will get saved regs.
1806			 */
1807			if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1808				rec->flags |= FTRACE_FL_REGS;
1809		} else {
1810			if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1811				return false;
1812			rec->flags--;
1813
1814			/*
1815			 * Only the internal direct_ops should have the
1816			 * DIRECT flag set. Thus, if it is removing a
1817			 * function, then that function should no longer
1818			 * be direct.
1819			 */
1820			if (ops->flags & FTRACE_OPS_FL_DIRECT)
1821				rec->flags &= ~FTRACE_FL_DIRECT;
1822
1823			/*
1824			 * If the rec had REGS enabled and the ops that is
1825			 * being removed had REGS set, then see if there is
1826			 * still any ops for this record that wants regs.
1827			 * If not, we can stop recording them.
1828			 */
1829			if (ftrace_rec_count(rec) > 0 &&
1830			    rec->flags & FTRACE_FL_REGS &&
1831			    ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1832				if (!test_rec_ops_needs_regs(rec))
1833					rec->flags &= ~FTRACE_FL_REGS;
1834			}
1835
1836			/*
1837			 * The TRAMP needs to be set only if rec count
1838			 * is decremented to one, and the ops that is
1839			 * left has a trampoline. As TRAMP can only be
1840			 * enabled if there is only a single ops attached
1841			 * to it.
1842			 */
1843			if (ftrace_rec_count(rec) == 1 &&
1844			    ftrace_find_tramp_ops_any_other(rec, ops))
1845				rec->flags |= FTRACE_FL_TRAMP;
1846			else
1847				rec->flags &= ~FTRACE_FL_TRAMP;
1848
1849			/*
1850			 * flags will be cleared in ftrace_check_record()
1851			 * if rec count is zero.
1852			 */
1853		}
1854
1855		/*
1856		 * If the rec has a single associated ops, and ops->func can be
1857		 * called directly, allow the call site to call via the ops.
1858		 */
1859		if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS) &&
1860		    ftrace_rec_count(rec) == 1 &&
1861		    ftrace_ops_get_func(ops) == ops->func)
1862			rec->flags |= FTRACE_FL_CALL_OPS;
1863		else
1864			rec->flags &= ~FTRACE_FL_CALL_OPS;
1865
1866		count++;
1867
1868		/* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1869		update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1870
1871		/* Shortcut, if we handled all records, we are done. */
1872		if (!all && count == hash->count)
1873			return update;
1874	} while_for_each_ftrace_rec();
1875
1876	return update;
1877}
1878
1879static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1880				    int filter_hash)
1881{
1882	return __ftrace_hash_rec_update(ops, filter_hash, 0);
1883}
1884
1885static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1886				   int filter_hash)
1887{
1888	return __ftrace_hash_rec_update(ops, filter_hash, 1);
1889}
1890
1891static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1892					  int filter_hash, int inc)
1893{
1894	struct ftrace_ops *op;
1895
1896	__ftrace_hash_rec_update(ops, filter_hash, inc);
1897
1898	if (ops->func_hash != &global_ops.local_hash)
1899		return;
1900
1901	/*
1902	 * If the ops shares the global_ops hash, then we need to update
1903	 * all ops that are enabled and use this hash.
1904	 */
1905	do_for_each_ftrace_op(op, ftrace_ops_list) {
1906		/* Already done */
1907		if (op == ops)
1908			continue;
1909		if (op->func_hash == &global_ops.local_hash)
1910			__ftrace_hash_rec_update(op, filter_hash, inc);
1911	} while_for_each_ftrace_op(op);
1912}
1913
1914static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1915					   int filter_hash)
1916{
1917	ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1918}
1919
1920static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1921					  int filter_hash)
1922{
1923	ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1924}
1925
1926/*
1927 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1928 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1929 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1930 * Note that old_hash and new_hash has below meanings
1931 *  - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1932 *  - If the hash is EMPTY_HASH, it hits nothing
1933 *  - Anything else hits the recs which match the hash entries.
1934 *
1935 * DIRECT ops does not have IPMODIFY flag, but we still need to check it
1936 * against functions with FTRACE_FL_IPMODIFY. If there is any overlap, call
1937 * ops_func(SHARE_IPMODIFY_SELF) to make sure current ops can share with
1938 * IPMODIFY. If ops_func(SHARE_IPMODIFY_SELF) returns non-zero, propagate
1939 * the return value to the caller and eventually to the owner of the DIRECT
1940 * ops.
1941 */
1942static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1943					 struct ftrace_hash *old_hash,
1944					 struct ftrace_hash *new_hash)
1945{
1946	struct ftrace_page *pg;
1947	struct dyn_ftrace *rec, *end = NULL;
1948	int in_old, in_new;
1949	bool is_ipmodify, is_direct;
1950
1951	/* Only update if the ops has been registered */
1952	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1953		return 0;
1954
1955	is_ipmodify = ops->flags & FTRACE_OPS_FL_IPMODIFY;
1956	is_direct = ops->flags & FTRACE_OPS_FL_DIRECT;
1957
1958	/* neither IPMODIFY nor DIRECT, skip */
1959	if (!is_ipmodify && !is_direct)
1960		return 0;
1961
1962	if (WARN_ON_ONCE(is_ipmodify && is_direct))
1963		return 0;
1964
1965	/*
1966	 * Since the IPMODIFY and DIRECT are very address sensitive
1967	 * actions, we do not allow ftrace_ops to set all functions to new
1968	 * hash.
1969	 */
1970	if (!new_hash || !old_hash)
1971		return -EINVAL;
1972
1973	/* Update rec->flags */
1974	do_for_each_ftrace_rec(pg, rec) {
1975
1976		if (rec->flags & FTRACE_FL_DISABLED)
1977			continue;
1978
1979		/* We need to update only differences of filter_hash */
1980		in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1981		in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1982		if (in_old == in_new)
1983			continue;
1984
1985		if (in_new) {
1986			if (rec->flags & FTRACE_FL_IPMODIFY) {
1987				int ret;
1988
1989				/* Cannot have two ipmodify on same rec */
1990				if (is_ipmodify)
1991					goto rollback;
1992
1993				FTRACE_WARN_ON(rec->flags & FTRACE_FL_DIRECT);
1994
1995				/*
1996				 * Another ops with IPMODIFY is already
1997				 * attached. We are now attaching a direct
1998				 * ops. Run SHARE_IPMODIFY_SELF, to check
1999				 * whether sharing is supported.
2000				 */
2001				if (!ops->ops_func)
2002					return -EBUSY;
2003				ret = ops->ops_func(ops, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF);
2004				if (ret)
2005					return ret;
2006			} else if (is_ipmodify) {
2007				rec->flags |= FTRACE_FL_IPMODIFY;
2008			}
2009		} else if (is_ipmodify) {
2010			rec->flags &= ~FTRACE_FL_IPMODIFY;
2011		}
2012	} while_for_each_ftrace_rec();
2013
2014	return 0;
2015
2016rollback:
2017	end = rec;
2018
2019	/* Roll back what we did above */
2020	do_for_each_ftrace_rec(pg, rec) {
2021
2022		if (rec->flags & FTRACE_FL_DISABLED)
2023			continue;
2024
2025		if (rec == end)
2026			goto err_out;
2027
2028		in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
2029		in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
2030		if (in_old == in_new)
2031			continue;
2032
2033		if (in_new)
2034			rec->flags &= ~FTRACE_FL_IPMODIFY;
2035		else
2036			rec->flags |= FTRACE_FL_IPMODIFY;
2037	} while_for_each_ftrace_rec();
2038
2039err_out:
2040	return -EBUSY;
2041}
2042
2043static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
2044{
2045	struct ftrace_hash *hash = ops->func_hash->filter_hash;
2046
2047	if (ftrace_hash_empty(hash))
2048		hash = NULL;
2049
2050	return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
2051}
2052
2053/* Disabling always succeeds */
2054static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
2055{
2056	struct ftrace_hash *hash = ops->func_hash->filter_hash;
2057
2058	if (ftrace_hash_empty(hash))
2059		hash = NULL;
2060
2061	__ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
2062}
2063
2064static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
2065				       struct ftrace_hash *new_hash)
2066{
2067	struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
2068
2069	if (ftrace_hash_empty(old_hash))
2070		old_hash = NULL;
2071
2072	if (ftrace_hash_empty(new_hash))
2073		new_hash = NULL;
2074
2075	return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
2076}
2077
2078static void print_ip_ins(const char *fmt, const unsigned char *p)
2079{
2080	char ins[MCOUNT_INSN_SIZE];
2081
2082	if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
2083		printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
2084		return;
2085	}
2086
2087	printk(KERN_CONT "%s", fmt);
2088	pr_cont("%*phC", MCOUNT_INSN_SIZE, ins);
2089}
2090
2091enum ftrace_bug_type ftrace_bug_type;
2092const void *ftrace_expected;
2093
2094static void print_bug_type(void)
2095{
2096	switch (ftrace_bug_type) {
2097	case FTRACE_BUG_UNKNOWN:
2098		break;
2099	case FTRACE_BUG_INIT:
2100		pr_info("Initializing ftrace call sites\n");
2101		break;
2102	case FTRACE_BUG_NOP:
2103		pr_info("Setting ftrace call site to NOP\n");
2104		break;
2105	case FTRACE_BUG_CALL:
2106		pr_info("Setting ftrace call site to call ftrace function\n");
2107		break;
2108	case FTRACE_BUG_UPDATE:
2109		pr_info("Updating ftrace call site to call a different ftrace function\n");
2110		break;
2111	}
2112}
2113
2114/**
2115 * ftrace_bug - report and shutdown function tracer
2116 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2117 * @rec: The record that failed
2118 *
2119 * The arch code that enables or disables the function tracing
2120 * can call ftrace_bug() when it has detected a problem in
2121 * modifying the code. @failed should be one of either:
2122 * EFAULT - if the problem happens on reading the @ip address
2123 * EINVAL - if what is read at @ip is not what was expected
2124 * EPERM - if the problem happens on writing to the @ip address
2125 */
2126void ftrace_bug(int failed, struct dyn_ftrace *rec)
2127{
2128	unsigned long ip = rec ? rec->ip : 0;
2129
2130	pr_info("------------[ ftrace bug ]------------\n");
2131
2132	switch (failed) {
2133	case -EFAULT:
2134		pr_info("ftrace faulted on modifying ");
2135		print_ip_sym(KERN_INFO, ip);
2136		break;
2137	case -EINVAL:
2138		pr_info("ftrace failed to modify ");
2139		print_ip_sym(KERN_INFO, ip);
2140		print_ip_ins(" actual:   ", (unsigned char *)ip);
2141		pr_cont("\n");
2142		if (ftrace_expected) {
2143			print_ip_ins(" expected: ", ftrace_expected);
2144			pr_cont("\n");
2145		}
2146		break;
2147	case -EPERM:
2148		pr_info("ftrace faulted on writing ");
2149		print_ip_sym(KERN_INFO, ip);
2150		break;
2151	default:
2152		pr_info("ftrace faulted on unknown error ");
2153		print_ip_sym(KERN_INFO, ip);
2154	}
2155	print_bug_type();
2156	if (rec) {
2157		struct ftrace_ops *ops = NULL;
2158
2159		pr_info("ftrace record flags: %lx\n", rec->flags);
2160		pr_cont(" (%ld)%s%s", ftrace_rec_count(rec),
2161			rec->flags & FTRACE_FL_REGS ? " R" : "  ",
2162			rec->flags & FTRACE_FL_CALL_OPS ? " O" : "  ");
2163		if (rec->flags & FTRACE_FL_TRAMP_EN) {
2164			ops = ftrace_find_tramp_ops_any(rec);
2165			if (ops) {
2166				do {
2167					pr_cont("\ttramp: %pS (%pS)",
2168						(void *)ops->trampoline,
2169						(void *)ops->func);
2170					ops = ftrace_find_tramp_ops_next(rec, ops);
2171				} while (ops);
2172			} else
2173				pr_cont("\ttramp: ERROR!");
2174
2175		}
2176		ip = ftrace_get_addr_curr(rec);
2177		pr_cont("\n expected tramp: %lx\n", ip);
2178	}
2179
2180	FTRACE_WARN_ON_ONCE(1);
2181}
2182
2183static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2184{
2185	unsigned long flag = 0UL;
2186
2187	ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2188
2189	if (skip_record(rec))
2190		return FTRACE_UPDATE_IGNORE;
2191
2192	/*
2193	 * If we are updating calls:
2194	 *
2195	 *   If the record has a ref count, then we need to enable it
2196	 *   because someone is using it.
2197	 *
2198	 *   Otherwise we make sure its disabled.
2199	 *
2200	 * If we are disabling calls, then disable all records that
2201	 * are enabled.
2202	 */
2203	if (enable && ftrace_rec_count(rec))
2204		flag = FTRACE_FL_ENABLED;
2205
2206	/*
2207	 * If enabling and the REGS flag does not match the REGS_EN, or
2208	 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2209	 * this record. Set flags to fail the compare against ENABLED.
2210	 * Same for direct calls.
2211	 */
2212	if (flag) {
2213		if (!(rec->flags & FTRACE_FL_REGS) !=
2214		    !(rec->flags & FTRACE_FL_REGS_EN))
2215			flag |= FTRACE_FL_REGS;
2216
2217		if (!(rec->flags & FTRACE_FL_TRAMP) !=
2218		    !(rec->flags & FTRACE_FL_TRAMP_EN))
2219			flag |= FTRACE_FL_TRAMP;
2220
2221		/*
2222		 * Direct calls are special, as count matters.
2223		 * We must test the record for direct, if the
2224		 * DIRECT and DIRECT_EN do not match, but only
2225		 * if the count is 1. That's because, if the
2226		 * count is something other than one, we do not
2227		 * want the direct enabled (it will be done via the
2228		 * direct helper). But if DIRECT_EN is set, and
2229		 * the count is not one, we need to clear it.
2230		 *
2231		 */
2232		if (ftrace_rec_count(rec) == 1) {
2233			if (!(rec->flags & FTRACE_FL_DIRECT) !=
2234			    !(rec->flags & FTRACE_FL_DIRECT_EN))
2235				flag |= FTRACE_FL_DIRECT;
2236		} else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2237			flag |= FTRACE_FL_DIRECT;
2238		}
2239
2240		/*
2241		 * Ops calls are special, as count matters.
2242		 * As with direct calls, they must only be enabled when count
2243		 * is one, otherwise they'll be handled via the list ops.
2244		 */
2245		if (ftrace_rec_count(rec) == 1) {
2246			if (!(rec->flags & FTRACE_FL_CALL_OPS) !=
2247			    !(rec->flags & FTRACE_FL_CALL_OPS_EN))
2248				flag |= FTRACE_FL_CALL_OPS;
2249		} else if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
2250			flag |= FTRACE_FL_CALL_OPS;
2251		}
2252	}
2253
2254	/* If the state of this record hasn't changed, then do nothing */
2255	if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2256		return FTRACE_UPDATE_IGNORE;
2257
2258	if (flag) {
2259		/* Save off if rec is being enabled (for return value) */
2260		flag ^= rec->flags & FTRACE_FL_ENABLED;
2261
2262		if (update) {
2263			rec->flags |= FTRACE_FL_ENABLED | FTRACE_FL_TOUCHED;
2264			if (flag & FTRACE_FL_REGS) {
2265				if (rec->flags & FTRACE_FL_REGS)
2266					rec->flags |= FTRACE_FL_REGS_EN;
2267				else
2268					rec->flags &= ~FTRACE_FL_REGS_EN;
2269			}
2270			if (flag & FTRACE_FL_TRAMP) {
2271				if (rec->flags & FTRACE_FL_TRAMP)
2272					rec->flags |= FTRACE_FL_TRAMP_EN;
2273				else
2274					rec->flags &= ~FTRACE_FL_TRAMP_EN;
2275			}
2276
2277			/* Keep track of anything that modifies the function */
2278			if (rec->flags & (FTRACE_FL_DIRECT | FTRACE_FL_IPMODIFY))
2279				rec->flags |= FTRACE_FL_MODIFIED;
2280
2281			if (flag & FTRACE_FL_DIRECT) {
2282				/*
2283				 * If there's only one user (direct_ops helper)
2284				 * then we can call the direct function
2285				 * directly (no ftrace trampoline).
2286				 */
2287				if (ftrace_rec_count(rec) == 1) {
2288					if (rec->flags & FTRACE_FL_DIRECT)
2289						rec->flags |= FTRACE_FL_DIRECT_EN;
2290					else
2291						rec->flags &= ~FTRACE_FL_DIRECT_EN;
2292				} else {
2293					/*
2294					 * Can only call directly if there's
2295					 * only one callback to the function.
2296					 */
2297					rec->flags &= ~FTRACE_FL_DIRECT_EN;
2298				}
2299			}
2300
2301			if (flag & FTRACE_FL_CALL_OPS) {
2302				if (ftrace_rec_count(rec) == 1) {
2303					if (rec->flags & FTRACE_FL_CALL_OPS)
2304						rec->flags |= FTRACE_FL_CALL_OPS_EN;
2305					else
2306						rec->flags &= ~FTRACE_FL_CALL_OPS_EN;
2307				} else {
2308					/*
2309					 * Can only call directly if there's
2310					 * only one set of associated ops.
2311					 */
2312					rec->flags &= ~FTRACE_FL_CALL_OPS_EN;
2313				}
2314			}
2315		}
2316
2317		/*
2318		 * If this record is being updated from a nop, then
2319		 *   return UPDATE_MAKE_CALL.
2320		 * Otherwise,
2321		 *   return UPDATE_MODIFY_CALL to tell the caller to convert
2322		 *   from the save regs, to a non-save regs function or
2323		 *   vice versa, or from a trampoline call.
2324		 */
2325		if (flag & FTRACE_FL_ENABLED) {
2326			ftrace_bug_type = FTRACE_BUG_CALL;
2327			return FTRACE_UPDATE_MAKE_CALL;
2328		}
2329
2330		ftrace_bug_type = FTRACE_BUG_UPDATE;
2331		return FTRACE_UPDATE_MODIFY_CALL;
2332	}
2333
2334	if (update) {
2335		/* If there's no more users, clear all flags */
2336		if (!ftrace_rec_count(rec))
2337			rec->flags &= FTRACE_NOCLEAR_FLAGS;
2338		else
2339			/*
2340			 * Just disable the record, but keep the ops TRAMP
2341			 * and REGS states. The _EN flags must be disabled though.
2342			 */
2343			rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2344					FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN |
2345					FTRACE_FL_CALL_OPS_EN);
2346	}
2347
2348	ftrace_bug_type = FTRACE_BUG_NOP;
2349	return FTRACE_UPDATE_MAKE_NOP;
2350}
2351
2352/**
2353 * ftrace_update_record - set a record that now is tracing or not
2354 * @rec: the record to update
2355 * @enable: set to true if the record is tracing, false to force disable
2356 *
2357 * The records that represent all functions that can be traced need
2358 * to be updated when tracing has been enabled.
2359 */
2360int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2361{
2362	return ftrace_check_record(rec, enable, true);
2363}
2364
2365/**
2366 * ftrace_test_record - check if the record has been enabled or not
2367 * @rec: the record to test
2368 * @enable: set to true to check if enabled, false if it is disabled
2369 *
2370 * The arch code may need to test if a record is already set to
2371 * tracing to determine how to modify the function code that it
2372 * represents.
2373 */
2374int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2375{
2376	return ftrace_check_record(rec, enable, false);
2377}
2378
2379static struct ftrace_ops *
2380ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2381{
2382	struct ftrace_ops *op;
2383	unsigned long ip = rec->ip;
2384
2385	do_for_each_ftrace_op(op, ftrace_ops_list) {
2386
2387		if (!op->trampoline)
2388			continue;
2389
2390		if (hash_contains_ip(ip, op->func_hash))
2391			return op;
2392	} while_for_each_ftrace_op(op);
2393
2394	return NULL;
2395}
2396
2397static struct ftrace_ops *
2398ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2399{
2400	struct ftrace_ops *op;
2401	unsigned long ip = rec->ip;
2402
2403	do_for_each_ftrace_op(op, ftrace_ops_list) {
2404
2405		if (op == op_exclude || !op->trampoline)
2406			continue;
2407
2408		if (hash_contains_ip(ip, op->func_hash))
2409			return op;
2410	} while_for_each_ftrace_op(op);
2411
2412	return NULL;
2413}
2414
2415static struct ftrace_ops *
2416ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2417			   struct ftrace_ops *op)
2418{
2419	unsigned long ip = rec->ip;
2420
2421	while_for_each_ftrace_op(op) {
2422
2423		if (!op->trampoline)
2424			continue;
2425
2426		if (hash_contains_ip(ip, op->func_hash))
2427			return op;
2428	}
2429
2430	return NULL;
2431}
2432
2433static struct ftrace_ops *
2434ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2435{
2436	struct ftrace_ops *op;
2437	unsigned long ip = rec->ip;
2438
2439	/*
2440	 * Need to check removed ops first.
2441	 * If they are being removed, and this rec has a tramp,
2442	 * and this rec is in the ops list, then it would be the
2443	 * one with the tramp.
2444	 */
2445	if (removed_ops) {
2446		if (hash_contains_ip(ip, &removed_ops->old_hash))
2447			return removed_ops;
2448	}
2449
2450	/*
2451	 * Need to find the current trampoline for a rec.
2452	 * Now, a trampoline is only attached to a rec if there
2453	 * was a single 'ops' attached to it. But this can be called
2454	 * when we are adding another op to the rec or removing the
2455	 * current one. Thus, if the op is being added, we can
2456	 * ignore it because it hasn't attached itself to the rec
2457	 * yet.
2458	 *
2459	 * If an ops is being modified (hooking to different functions)
2460	 * then we don't care about the new functions that are being
2461	 * added, just the old ones (that are probably being removed).
2462	 *
2463	 * If we are adding an ops to a function that already is using
2464	 * a trampoline, it needs to be removed (trampolines are only
2465	 * for single ops connected), then an ops that is not being
2466	 * modified also needs to be checked.
2467	 */
2468	do_for_each_ftrace_op(op, ftrace_ops_list) {
2469
2470		if (!op->trampoline)
2471			continue;
2472
2473		/*
2474		 * If the ops is being added, it hasn't gotten to
2475		 * the point to be removed from this tree yet.
2476		 */
2477		if (op->flags & FTRACE_OPS_FL_ADDING)
2478			continue;
2479
2480
2481		/*
2482		 * If the ops is being modified and is in the old
2483		 * hash, then it is probably being removed from this
2484		 * function.
2485		 */
2486		if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2487		    hash_contains_ip(ip, &op->old_hash))
2488			return op;
2489		/*
2490		 * If the ops is not being added or modified, and it's
2491		 * in its normal filter hash, then this must be the one
2492		 * we want!
2493		 */
2494		if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2495		    hash_contains_ip(ip, op->func_hash))
2496			return op;
2497
2498	} while_for_each_ftrace_op(op);
2499
2500	return NULL;
2501}
2502
2503static struct ftrace_ops *
2504ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2505{
2506	struct ftrace_ops *op;
2507	unsigned long ip = rec->ip;
2508
2509	do_for_each_ftrace_op(op, ftrace_ops_list) {
2510		/* pass rec in as regs to have non-NULL val */
2511		if (hash_contains_ip(ip, op->func_hash))
2512			return op;
2513	} while_for_each_ftrace_op(op);
2514
2515	return NULL;
2516}
2517
2518struct ftrace_ops *
2519ftrace_find_unique_ops(struct dyn_ftrace *rec)
2520{
2521	struct ftrace_ops *op, *found = NULL;
2522	unsigned long ip = rec->ip;
2523
2524	do_for_each_ftrace_op(op, ftrace_ops_list) {
2525
2526		if (hash_contains_ip(ip, op->func_hash)) {
2527			if (found)
2528				return NULL;
2529			found = op;
2530		}
2531
2532	} while_for_each_ftrace_op(op);
2533
2534	return found;
2535}
2536
2537#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2538/* Protected by rcu_tasks for reading, and direct_mutex for writing */
2539static struct ftrace_hash __rcu *direct_functions = EMPTY_HASH;
2540static DEFINE_MUTEX(direct_mutex);
2541int ftrace_direct_func_count;
2542
2543/*
2544 * Search the direct_functions hash to see if the given instruction pointer
2545 * has a direct caller attached to it.
2546 */
2547unsigned long ftrace_find_rec_direct(unsigned long ip)
2548{
2549	struct ftrace_func_entry *entry;
2550
2551	entry = __ftrace_lookup_ip(direct_functions, ip);
2552	if (!entry)
2553		return 0;
2554
2555	return entry->direct;
2556}
2557
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2558static void call_direct_funcs(unsigned long ip, unsigned long pip,
2559			      struct ftrace_ops *ops, struct ftrace_regs *fregs)
2560{
2561	unsigned long addr = READ_ONCE(ops->direct_call);
2562
 
2563	if (!addr)
2564		return;
2565
2566	arch_ftrace_set_direct_caller(fregs, addr);
2567}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2568#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2569
2570/**
2571 * ftrace_get_addr_new - Get the call address to set to
2572 * @rec:  The ftrace record descriptor
2573 *
2574 * If the record has the FTRACE_FL_REGS set, that means that it
2575 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2576 * is not set, then it wants to convert to the normal callback.
2577 *
2578 * Returns: the address of the trampoline to set to
2579 */
2580unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2581{
2582	struct ftrace_ops *ops;
2583	unsigned long addr;
2584
2585	if ((rec->flags & FTRACE_FL_DIRECT) &&
2586	    (ftrace_rec_count(rec) == 1)) {
2587		addr = ftrace_find_rec_direct(rec->ip);
2588		if (addr)
2589			return addr;
2590		WARN_ON_ONCE(1);
2591	}
2592
2593	/* Trampolines take precedence over regs */
2594	if (rec->flags & FTRACE_FL_TRAMP) {
2595		ops = ftrace_find_tramp_ops_new(rec);
2596		if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2597			pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2598				(void *)rec->ip, (void *)rec->ip, rec->flags);
2599			/* Ftrace is shutting down, return anything */
2600			return (unsigned long)FTRACE_ADDR;
2601		}
2602		return ops->trampoline;
2603	}
2604
2605	if (rec->flags & FTRACE_FL_REGS)
2606		return (unsigned long)FTRACE_REGS_ADDR;
2607	else
2608		return (unsigned long)FTRACE_ADDR;
2609}
2610
2611/**
2612 * ftrace_get_addr_curr - Get the call address that is already there
2613 * @rec:  The ftrace record descriptor
2614 *
2615 * The FTRACE_FL_REGS_EN is set when the record already points to
2616 * a function that saves all the regs. Basically the '_EN' version
2617 * represents the current state of the function.
2618 *
2619 * Returns: the address of the trampoline that is currently being called
2620 */
2621unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2622{
2623	struct ftrace_ops *ops;
2624	unsigned long addr;
2625
2626	/* Direct calls take precedence over trampolines */
2627	if (rec->flags & FTRACE_FL_DIRECT_EN) {
2628		addr = ftrace_find_rec_direct(rec->ip);
2629		if (addr)
2630			return addr;
2631		WARN_ON_ONCE(1);
2632	}
2633
2634	/* Trampolines take precedence over regs */
2635	if (rec->flags & FTRACE_FL_TRAMP_EN) {
2636		ops = ftrace_find_tramp_ops_curr(rec);
2637		if (FTRACE_WARN_ON(!ops)) {
2638			pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2639				(void *)rec->ip, (void *)rec->ip);
2640			/* Ftrace is shutting down, return anything */
2641			return (unsigned long)FTRACE_ADDR;
2642		}
2643		return ops->trampoline;
2644	}
2645
2646	if (rec->flags & FTRACE_FL_REGS_EN)
2647		return (unsigned long)FTRACE_REGS_ADDR;
2648	else
2649		return (unsigned long)FTRACE_ADDR;
2650}
2651
2652static int
2653__ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2654{
2655	unsigned long ftrace_old_addr;
2656	unsigned long ftrace_addr;
2657	int ret;
2658
2659	ftrace_addr = ftrace_get_addr_new(rec);
2660
2661	/* This needs to be done before we call ftrace_update_record */
2662	ftrace_old_addr = ftrace_get_addr_curr(rec);
2663
2664	ret = ftrace_update_record(rec, enable);
2665
2666	ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2667
2668	switch (ret) {
2669	case FTRACE_UPDATE_IGNORE:
2670		return 0;
2671
2672	case FTRACE_UPDATE_MAKE_CALL:
2673		ftrace_bug_type = FTRACE_BUG_CALL;
2674		return ftrace_make_call(rec, ftrace_addr);
2675
2676	case FTRACE_UPDATE_MAKE_NOP:
2677		ftrace_bug_type = FTRACE_BUG_NOP;
2678		return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2679
2680	case FTRACE_UPDATE_MODIFY_CALL:
2681		ftrace_bug_type = FTRACE_BUG_UPDATE;
2682		return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2683	}
2684
2685	return -1; /* unknown ftrace bug */
2686}
2687
2688void __weak ftrace_replace_code(int mod_flags)
2689{
2690	struct dyn_ftrace *rec;
2691	struct ftrace_page *pg;
2692	bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2693	int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2694	int failed;
2695
2696	if (unlikely(ftrace_disabled))
2697		return;
2698
2699	do_for_each_ftrace_rec(pg, rec) {
2700
2701		if (skip_record(rec))
2702			continue;
2703
2704		failed = __ftrace_replace_code(rec, enable);
2705		if (failed) {
2706			ftrace_bug(failed, rec);
2707			/* Stop processing */
2708			return;
2709		}
2710		if (schedulable)
2711			cond_resched();
2712	} while_for_each_ftrace_rec();
2713}
2714
2715struct ftrace_rec_iter {
2716	struct ftrace_page	*pg;
2717	int			index;
2718};
2719
2720/**
2721 * ftrace_rec_iter_start - start up iterating over traced functions
2722 *
2723 * Returns: an iterator handle that is used to iterate over all
2724 * the records that represent address locations where functions
2725 * are traced.
2726 *
2727 * May return NULL if no records are available.
2728 */
2729struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2730{
2731	/*
2732	 * We only use a single iterator.
2733	 * Protected by the ftrace_lock mutex.
2734	 */
2735	static struct ftrace_rec_iter ftrace_rec_iter;
2736	struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2737
2738	iter->pg = ftrace_pages_start;
2739	iter->index = 0;
2740
2741	/* Could have empty pages */
2742	while (iter->pg && !iter->pg->index)
2743		iter->pg = iter->pg->next;
2744
2745	if (!iter->pg)
2746		return NULL;
2747
2748	return iter;
2749}
2750
2751/**
2752 * ftrace_rec_iter_next - get the next record to process.
2753 * @iter: The handle to the iterator.
2754 *
2755 * Returns: the next iterator after the given iterator @iter.
2756 */
2757struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2758{
2759	iter->index++;
2760
2761	if (iter->index >= iter->pg->index) {
2762		iter->pg = iter->pg->next;
2763		iter->index = 0;
2764
2765		/* Could have empty pages */
2766		while (iter->pg && !iter->pg->index)
2767			iter->pg = iter->pg->next;
2768	}
2769
2770	if (!iter->pg)
2771		return NULL;
2772
2773	return iter;
2774}
2775
2776/**
2777 * ftrace_rec_iter_record - get the record at the iterator location
2778 * @iter: The current iterator location
2779 *
2780 * Returns: the record that the current @iter is at.
2781 */
2782struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2783{
2784	return &iter->pg->records[iter->index];
2785}
2786
2787static int
2788ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2789{
2790	int ret;
2791
2792	if (unlikely(ftrace_disabled))
2793		return 0;
2794
2795	ret = ftrace_init_nop(mod, rec);
2796	if (ret) {
2797		ftrace_bug_type = FTRACE_BUG_INIT;
2798		ftrace_bug(ret, rec);
2799		return 0;
2800	}
2801	return 1;
2802}
2803
2804/*
2805 * archs can override this function if they must do something
2806 * before the modifying code is performed.
2807 */
2808void __weak ftrace_arch_code_modify_prepare(void)
2809{
2810}
2811
2812/*
2813 * archs can override this function if they must do something
2814 * after the modifying code is performed.
2815 */
2816void __weak ftrace_arch_code_modify_post_process(void)
2817{
2818}
2819
2820static int update_ftrace_func(ftrace_func_t func)
2821{
2822	static ftrace_func_t save_func;
2823
2824	/* Avoid updating if it hasn't changed */
2825	if (func == save_func)
2826		return 0;
2827
2828	save_func = func;
2829
2830	return ftrace_update_ftrace_func(func);
2831}
2832
2833void ftrace_modify_all_code(int command)
2834{
2835	int update = command & FTRACE_UPDATE_TRACE_FUNC;
2836	int mod_flags = 0;
2837	int err = 0;
2838
2839	if (command & FTRACE_MAY_SLEEP)
2840		mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2841
2842	/*
2843	 * If the ftrace_caller calls a ftrace_ops func directly,
2844	 * we need to make sure that it only traces functions it
2845	 * expects to trace. When doing the switch of functions,
2846	 * we need to update to the ftrace_ops_list_func first
2847	 * before the transition between old and new calls are set,
2848	 * as the ftrace_ops_list_func will check the ops hashes
2849	 * to make sure the ops are having the right functions
2850	 * traced.
2851	 */
2852	if (update) {
2853		err = update_ftrace_func(ftrace_ops_list_func);
2854		if (FTRACE_WARN_ON(err))
2855			return;
2856	}
2857
2858	if (command & FTRACE_UPDATE_CALLS)
2859		ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2860	else if (command & FTRACE_DISABLE_CALLS)
2861		ftrace_replace_code(mod_flags);
2862
2863	if (update && ftrace_trace_function != ftrace_ops_list_func) {
2864		function_trace_op = set_function_trace_op;
2865		smp_wmb();
2866		/* If irqs are disabled, we are in stop machine */
2867		if (!irqs_disabled())
2868			smp_call_function(ftrace_sync_ipi, NULL, 1);
2869		err = update_ftrace_func(ftrace_trace_function);
2870		if (FTRACE_WARN_ON(err))
2871			return;
2872	}
2873
2874	if (command & FTRACE_START_FUNC_RET)
2875		err = ftrace_enable_ftrace_graph_caller();
2876	else if (command & FTRACE_STOP_FUNC_RET)
2877		err = ftrace_disable_ftrace_graph_caller();
2878	FTRACE_WARN_ON(err);
2879}
2880
2881static int __ftrace_modify_code(void *data)
2882{
2883	int *command = data;
2884
2885	ftrace_modify_all_code(*command);
2886
2887	return 0;
2888}
2889
2890/**
2891 * ftrace_run_stop_machine - go back to the stop machine method
2892 * @command: The command to tell ftrace what to do
2893 *
2894 * If an arch needs to fall back to the stop machine method, the
2895 * it can call this function.
2896 */
2897void ftrace_run_stop_machine(int command)
2898{
2899	stop_machine(__ftrace_modify_code, &command, NULL);
2900}
2901
2902/**
2903 * arch_ftrace_update_code - modify the code to trace or not trace
2904 * @command: The command that needs to be done
2905 *
2906 * Archs can override this function if it does not need to
2907 * run stop_machine() to modify code.
2908 */
2909void __weak arch_ftrace_update_code(int command)
2910{
2911	ftrace_run_stop_machine(command);
2912}
2913
2914static void ftrace_run_update_code(int command)
2915{
2916	ftrace_arch_code_modify_prepare();
2917
2918	/*
2919	 * By default we use stop_machine() to modify the code.
2920	 * But archs can do what ever they want as long as it
2921	 * is safe. The stop_machine() is the safest, but also
2922	 * produces the most overhead.
2923	 */
2924	arch_ftrace_update_code(command);
2925
2926	ftrace_arch_code_modify_post_process();
2927}
2928
2929static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2930				   struct ftrace_ops_hash *old_hash)
2931{
2932	ops->flags |= FTRACE_OPS_FL_MODIFYING;
2933	ops->old_hash.filter_hash = old_hash->filter_hash;
2934	ops->old_hash.notrace_hash = old_hash->notrace_hash;
2935	ftrace_run_update_code(command);
2936	ops->old_hash.filter_hash = NULL;
2937	ops->old_hash.notrace_hash = NULL;
2938	ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2939}
2940
2941static ftrace_func_t saved_ftrace_func;
2942static int ftrace_start_up;
2943
2944void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2945{
2946}
2947
2948/* List of trace_ops that have allocated trampolines */
2949static LIST_HEAD(ftrace_ops_trampoline_list);
2950
2951static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2952{
2953	lockdep_assert_held(&ftrace_lock);
2954	list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2955}
2956
2957static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2958{
2959	lockdep_assert_held(&ftrace_lock);
2960	list_del_rcu(&ops->list);
2961	synchronize_rcu();
2962}
2963
2964/*
2965 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2966 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2967 * not a module.
2968 */
2969#define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2970#define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2971
2972static void ftrace_trampoline_free(struct ftrace_ops *ops)
2973{
2974	if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
2975	    ops->trampoline) {
2976		/*
2977		 * Record the text poke event before the ksymbol unregister
2978		 * event.
2979		 */
2980		perf_event_text_poke((void *)ops->trampoline,
2981				     (void *)ops->trampoline,
2982				     ops->trampoline_size, NULL, 0);
2983		perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
2984				   ops->trampoline, ops->trampoline_size,
2985				   true, FTRACE_TRAMPOLINE_SYM);
2986		/* Remove from kallsyms after the perf events */
2987		ftrace_remove_trampoline_from_kallsyms(ops);
2988	}
2989
2990	arch_ftrace_trampoline_free(ops);
2991}
2992
2993static void ftrace_startup_enable(int command)
2994{
2995	if (saved_ftrace_func != ftrace_trace_function) {
2996		saved_ftrace_func = ftrace_trace_function;
2997		command |= FTRACE_UPDATE_TRACE_FUNC;
2998	}
2999
3000	if (!command || !ftrace_enabled)
3001		return;
3002
3003	ftrace_run_update_code(command);
3004}
3005
3006static void ftrace_startup_all(int command)
3007{
3008	update_all_ops = true;
3009	ftrace_startup_enable(command);
3010	update_all_ops = false;
3011}
3012
3013int ftrace_startup(struct ftrace_ops *ops, int command)
3014{
3015	int ret;
3016
3017	if (unlikely(ftrace_disabled))
3018		return -ENODEV;
3019
3020	ret = __register_ftrace_function(ops);
3021	if (ret)
3022		return ret;
3023
3024	ftrace_start_up++;
3025
3026	/*
3027	 * Note that ftrace probes uses this to start up
3028	 * and modify functions it will probe. But we still
3029	 * set the ADDING flag for modification, as probes
3030	 * do not have trampolines. If they add them in the
3031	 * future, then the probes will need to distinguish
3032	 * between adding and updating probes.
3033	 */
3034	ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
3035
3036	ret = ftrace_hash_ipmodify_enable(ops);
3037	if (ret < 0) {
3038		/* Rollback registration process */
3039		__unregister_ftrace_function(ops);
3040		ftrace_start_up--;
3041		ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3042		if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
3043			ftrace_trampoline_free(ops);
3044		return ret;
3045	}
3046
3047	if (ftrace_hash_rec_enable(ops, 1))
3048		command |= FTRACE_UPDATE_CALLS;
3049
3050	ftrace_startup_enable(command);
3051
3052	/*
3053	 * If ftrace is in an undefined state, we just remove ops from list
3054	 * to prevent the NULL pointer, instead of totally rolling it back and
3055	 * free trampoline, because those actions could cause further damage.
3056	 */
3057	if (unlikely(ftrace_disabled)) {
3058		__unregister_ftrace_function(ops);
3059		return -ENODEV;
3060	}
3061
3062	ops->flags &= ~FTRACE_OPS_FL_ADDING;
3063
3064	return 0;
3065}
3066
3067int ftrace_shutdown(struct ftrace_ops *ops, int command)
3068{
3069	int ret;
3070
3071	if (unlikely(ftrace_disabled))
3072		return -ENODEV;
3073
3074	ret = __unregister_ftrace_function(ops);
3075	if (ret)
3076		return ret;
3077
3078	ftrace_start_up--;
3079	/*
3080	 * Just warn in case of unbalance, no need to kill ftrace, it's not
3081	 * critical but the ftrace_call callers may be never nopped again after
3082	 * further ftrace uses.
3083	 */
3084	WARN_ON_ONCE(ftrace_start_up < 0);
3085
3086	/* Disabling ipmodify never fails */
3087	ftrace_hash_ipmodify_disable(ops);
3088
3089	if (ftrace_hash_rec_disable(ops, 1))
3090		command |= FTRACE_UPDATE_CALLS;
3091
3092	ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3093
3094	if (saved_ftrace_func != ftrace_trace_function) {
3095		saved_ftrace_func = ftrace_trace_function;
3096		command |= FTRACE_UPDATE_TRACE_FUNC;
3097	}
3098
3099	if (!command || !ftrace_enabled)
3100		goto out;
3101
3102	/*
3103	 * If the ops uses a trampoline, then it needs to be
3104	 * tested first on update.
3105	 */
3106	ops->flags |= FTRACE_OPS_FL_REMOVING;
3107	removed_ops = ops;
3108
3109	/* The trampoline logic checks the old hashes */
3110	ops->old_hash.filter_hash = ops->func_hash->filter_hash;
3111	ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
3112
3113	ftrace_run_update_code(command);
3114
3115	/*
3116	 * If there's no more ops registered with ftrace, run a
3117	 * sanity check to make sure all rec flags are cleared.
3118	 */
3119	if (rcu_dereference_protected(ftrace_ops_list,
3120			lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
3121		struct ftrace_page *pg;
3122		struct dyn_ftrace *rec;
3123
3124		do_for_each_ftrace_rec(pg, rec) {
3125			if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_NOCLEAR_FLAGS))
3126				pr_warn("  %pS flags:%lx\n",
3127					(void *)rec->ip, rec->flags);
3128		} while_for_each_ftrace_rec();
3129	}
3130
3131	ops->old_hash.filter_hash = NULL;
3132	ops->old_hash.notrace_hash = NULL;
3133
3134	removed_ops = NULL;
3135	ops->flags &= ~FTRACE_OPS_FL_REMOVING;
3136
3137out:
3138	/*
3139	 * Dynamic ops may be freed, we must make sure that all
3140	 * callers are done before leaving this function.
3141	 */
3142	if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
3143		/*
3144		 * We need to do a hard force of sched synchronization.
3145		 * This is because we use preempt_disable() to do RCU, but
3146		 * the function tracers can be called where RCU is not watching
3147		 * (like before user_exit()). We can not rely on the RCU
3148		 * infrastructure to do the synchronization, thus we must do it
3149		 * ourselves.
3150		 */
3151		synchronize_rcu_tasks_rude();
3152
3153		/*
3154		 * When the kernel is preemptive, tasks can be preempted
3155		 * while on a ftrace trampoline. Just scheduling a task on
3156		 * a CPU is not good enough to flush them. Calling
3157		 * synchronize_rcu_tasks() will wait for those tasks to
3158		 * execute and either schedule voluntarily or enter user space.
3159		 */
3160		if (IS_ENABLED(CONFIG_PREEMPTION))
3161			synchronize_rcu_tasks();
3162
3163		ftrace_trampoline_free(ops);
3164	}
3165
3166	return 0;
3167}
3168
3169static u64		ftrace_update_time;
3170unsigned long		ftrace_update_tot_cnt;
3171unsigned long		ftrace_number_of_pages;
3172unsigned long		ftrace_number_of_groups;
3173
3174static inline int ops_traces_mod(struct ftrace_ops *ops)
3175{
3176	/*
3177	 * Filter_hash being empty will default to trace module.
3178	 * But notrace hash requires a test of individual module functions.
3179	 */
3180	return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3181		ftrace_hash_empty(ops->func_hash->notrace_hash);
3182}
3183
3184static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3185{
3186	bool init_nop = ftrace_need_init_nop();
3187	struct ftrace_page *pg;
3188	struct dyn_ftrace *p;
3189	u64 start, stop;
3190	unsigned long update_cnt = 0;
3191	unsigned long rec_flags = 0;
3192	int i;
3193
3194	start = ftrace_now(raw_smp_processor_id());
3195
3196	/*
3197	 * When a module is loaded, this function is called to convert
3198	 * the calls to mcount in its text to nops, and also to create
3199	 * an entry in the ftrace data. Now, if ftrace is activated
3200	 * after this call, but before the module sets its text to
3201	 * read-only, the modification of enabling ftrace can fail if
3202	 * the read-only is done while ftrace is converting the calls.
3203	 * To prevent this, the module's records are set as disabled
3204	 * and will be enabled after the call to set the module's text
3205	 * to read-only.
3206	 */
3207	if (mod)
3208		rec_flags |= FTRACE_FL_DISABLED;
3209
3210	for (pg = new_pgs; pg; pg = pg->next) {
3211
3212		for (i = 0; i < pg->index; i++) {
3213
3214			/* If something went wrong, bail without enabling anything */
3215			if (unlikely(ftrace_disabled))
3216				return -1;
3217
3218			p = &pg->records[i];
3219			p->flags = rec_flags;
3220
3221			/*
3222			 * Do the initial record conversion from mcount jump
3223			 * to the NOP instructions.
3224			 */
3225			if (init_nop && !ftrace_nop_initialize(mod, p))
3226				break;
3227
3228			update_cnt++;
3229		}
3230	}
3231
3232	stop = ftrace_now(raw_smp_processor_id());
3233	ftrace_update_time = stop - start;
3234	ftrace_update_tot_cnt += update_cnt;
3235
3236	return 0;
3237}
3238
3239static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3240{
3241	int order;
3242	int pages;
3243	int cnt;
3244
3245	if (WARN_ON(!count))
3246		return -EINVAL;
3247
3248	/* We want to fill as much as possible, with no empty pages */
3249	pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3250	order = fls(pages) - 1;
3251
3252 again:
3253	pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3254
3255	if (!pg->records) {
3256		/* if we can't allocate this size, try something smaller */
3257		if (!order)
3258			return -ENOMEM;
3259		order--;
3260		goto again;
3261	}
3262
3263	ftrace_number_of_pages += 1 << order;
3264	ftrace_number_of_groups++;
3265
3266	cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3267	pg->order = order;
3268
3269	if (cnt > count)
3270		cnt = count;
3271
3272	return cnt;
3273}
3274
3275static void ftrace_free_pages(struct ftrace_page *pages)
3276{
3277	struct ftrace_page *pg = pages;
3278
3279	while (pg) {
3280		if (pg->records) {
3281			free_pages((unsigned long)pg->records, pg->order);
3282			ftrace_number_of_pages -= 1 << pg->order;
3283		}
3284		pages = pg->next;
3285		kfree(pg);
3286		pg = pages;
3287		ftrace_number_of_groups--;
3288	}
3289}
3290
3291static struct ftrace_page *
3292ftrace_allocate_pages(unsigned long num_to_init)
3293{
3294	struct ftrace_page *start_pg;
3295	struct ftrace_page *pg;
3296	int cnt;
3297
3298	if (!num_to_init)
3299		return NULL;
3300
3301	start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3302	if (!pg)
3303		return NULL;
3304
3305	/*
3306	 * Try to allocate as much as possible in one continues
3307	 * location that fills in all of the space. We want to
3308	 * waste as little space as possible.
3309	 */
3310	for (;;) {
3311		cnt = ftrace_allocate_records(pg, num_to_init);
3312		if (cnt < 0)
3313			goto free_pages;
3314
3315		num_to_init -= cnt;
3316		if (!num_to_init)
3317			break;
3318
3319		pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3320		if (!pg->next)
3321			goto free_pages;
3322
3323		pg = pg->next;
3324	}
3325
3326	return start_pg;
3327
3328 free_pages:
3329	ftrace_free_pages(start_pg);
 
 
 
 
 
 
 
 
 
 
3330	pr_info("ftrace: FAILED to allocate memory for functions\n");
3331	return NULL;
3332}
3333
3334#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3335
3336struct ftrace_iterator {
3337	loff_t				pos;
3338	loff_t				func_pos;
3339	loff_t				mod_pos;
3340	struct ftrace_page		*pg;
3341	struct dyn_ftrace		*func;
3342	struct ftrace_func_probe	*probe;
3343	struct ftrace_func_entry	*probe_entry;
3344	struct trace_parser		parser;
3345	struct ftrace_hash		*hash;
3346	struct ftrace_ops		*ops;
3347	struct trace_array		*tr;
3348	struct list_head		*mod_list;
3349	int				pidx;
3350	int				idx;
3351	unsigned			flags;
3352};
3353
3354static void *
3355t_probe_next(struct seq_file *m, loff_t *pos)
3356{
3357	struct ftrace_iterator *iter = m->private;
3358	struct trace_array *tr = iter->ops->private;
3359	struct list_head *func_probes;
3360	struct ftrace_hash *hash;
3361	struct list_head *next;
3362	struct hlist_node *hnd = NULL;
3363	struct hlist_head *hhd;
3364	int size;
3365
3366	(*pos)++;
3367	iter->pos = *pos;
3368
3369	if (!tr)
3370		return NULL;
3371
3372	func_probes = &tr->func_probes;
3373	if (list_empty(func_probes))
3374		return NULL;
3375
3376	if (!iter->probe) {
3377		next = func_probes->next;
3378		iter->probe = list_entry(next, struct ftrace_func_probe, list);
3379	}
3380
3381	if (iter->probe_entry)
3382		hnd = &iter->probe_entry->hlist;
3383
3384	hash = iter->probe->ops.func_hash->filter_hash;
3385
3386	/*
3387	 * A probe being registered may temporarily have an empty hash
3388	 * and it's at the end of the func_probes list.
3389	 */
3390	if (!hash || hash == EMPTY_HASH)
3391		return NULL;
3392
3393	size = 1 << hash->size_bits;
3394
3395 retry:
3396	if (iter->pidx >= size) {
3397		if (iter->probe->list.next == func_probes)
3398			return NULL;
3399		next = iter->probe->list.next;
3400		iter->probe = list_entry(next, struct ftrace_func_probe, list);
3401		hash = iter->probe->ops.func_hash->filter_hash;
3402		size = 1 << hash->size_bits;
3403		iter->pidx = 0;
3404	}
3405
3406	hhd = &hash->buckets[iter->pidx];
3407
3408	if (hlist_empty(hhd)) {
3409		iter->pidx++;
3410		hnd = NULL;
3411		goto retry;
3412	}
3413
3414	if (!hnd)
3415		hnd = hhd->first;
3416	else {
3417		hnd = hnd->next;
3418		if (!hnd) {
3419			iter->pidx++;
3420			goto retry;
3421		}
3422	}
3423
3424	if (WARN_ON_ONCE(!hnd))
3425		return NULL;
3426
3427	iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3428
3429	return iter;
3430}
3431
3432static void *t_probe_start(struct seq_file *m, loff_t *pos)
3433{
3434	struct ftrace_iterator *iter = m->private;
3435	void *p = NULL;
3436	loff_t l;
3437
3438	if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3439		return NULL;
3440
3441	if (iter->mod_pos > *pos)
3442		return NULL;
3443
3444	iter->probe = NULL;
3445	iter->probe_entry = NULL;
3446	iter->pidx = 0;
3447	for (l = 0; l <= (*pos - iter->mod_pos); ) {
3448		p = t_probe_next(m, &l);
3449		if (!p)
3450			break;
3451	}
3452	if (!p)
3453		return NULL;
3454
3455	/* Only set this if we have an item */
3456	iter->flags |= FTRACE_ITER_PROBE;
3457
3458	return iter;
3459}
3460
3461static int
3462t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3463{
3464	struct ftrace_func_entry *probe_entry;
3465	struct ftrace_probe_ops *probe_ops;
3466	struct ftrace_func_probe *probe;
3467
3468	probe = iter->probe;
3469	probe_entry = iter->probe_entry;
3470
3471	if (WARN_ON_ONCE(!probe || !probe_entry))
3472		return -EIO;
3473
3474	probe_ops = probe->probe_ops;
3475
3476	if (probe_ops->print)
3477		return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3478
3479	seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3480		   (void *)probe_ops->func);
3481
3482	return 0;
3483}
3484
3485static void *
3486t_mod_next(struct seq_file *m, loff_t *pos)
3487{
3488	struct ftrace_iterator *iter = m->private;
3489	struct trace_array *tr = iter->tr;
3490
3491	(*pos)++;
3492	iter->pos = *pos;
3493
3494	iter->mod_list = iter->mod_list->next;
3495
3496	if (iter->mod_list == &tr->mod_trace ||
3497	    iter->mod_list == &tr->mod_notrace) {
3498		iter->flags &= ~FTRACE_ITER_MOD;
3499		return NULL;
3500	}
3501
3502	iter->mod_pos = *pos;
3503
3504	return iter;
3505}
3506
3507static void *t_mod_start(struct seq_file *m, loff_t *pos)
3508{
3509	struct ftrace_iterator *iter = m->private;
3510	void *p = NULL;
3511	loff_t l;
3512
3513	if (iter->func_pos > *pos)
3514		return NULL;
3515
3516	iter->mod_pos = iter->func_pos;
3517
3518	/* probes are only available if tr is set */
3519	if (!iter->tr)
3520		return NULL;
3521
3522	for (l = 0; l <= (*pos - iter->func_pos); ) {
3523		p = t_mod_next(m, &l);
3524		if (!p)
3525			break;
3526	}
3527	if (!p) {
3528		iter->flags &= ~FTRACE_ITER_MOD;
3529		return t_probe_start(m, pos);
3530	}
3531
3532	/* Only set this if we have an item */
3533	iter->flags |= FTRACE_ITER_MOD;
3534
3535	return iter;
3536}
3537
3538static int
3539t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3540{
3541	struct ftrace_mod_load *ftrace_mod;
3542	struct trace_array *tr = iter->tr;
3543
3544	if (WARN_ON_ONCE(!iter->mod_list) ||
3545			 iter->mod_list == &tr->mod_trace ||
3546			 iter->mod_list == &tr->mod_notrace)
3547		return -EIO;
3548
3549	ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3550
3551	if (ftrace_mod->func)
3552		seq_printf(m, "%s", ftrace_mod->func);
3553	else
3554		seq_putc(m, '*');
3555
3556	seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3557
3558	return 0;
3559}
3560
3561static void *
3562t_func_next(struct seq_file *m, loff_t *pos)
3563{
3564	struct ftrace_iterator *iter = m->private;
3565	struct dyn_ftrace *rec = NULL;
3566
3567	(*pos)++;
3568
3569 retry:
3570	if (iter->idx >= iter->pg->index) {
3571		if (iter->pg->next) {
3572			iter->pg = iter->pg->next;
3573			iter->idx = 0;
3574			goto retry;
3575		}
3576	} else {
3577		rec = &iter->pg->records[iter->idx++];
3578		if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3579		     !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3580
3581		    ((iter->flags & FTRACE_ITER_ENABLED) &&
3582		     !(rec->flags & FTRACE_FL_ENABLED)) ||
3583
3584		    ((iter->flags & FTRACE_ITER_TOUCHED) &&
3585		     !(rec->flags & FTRACE_FL_TOUCHED))) {
3586
3587			rec = NULL;
3588			goto retry;
3589		}
3590	}
3591
3592	if (!rec)
3593		return NULL;
3594
3595	iter->pos = iter->func_pos = *pos;
3596	iter->func = rec;
3597
3598	return iter;
3599}
3600
3601static void *
3602t_next(struct seq_file *m, void *v, loff_t *pos)
3603{
3604	struct ftrace_iterator *iter = m->private;
3605	loff_t l = *pos; /* t_probe_start() must use original pos */
3606	void *ret;
3607
3608	if (unlikely(ftrace_disabled))
3609		return NULL;
3610
3611	if (iter->flags & FTRACE_ITER_PROBE)
3612		return t_probe_next(m, pos);
3613
3614	if (iter->flags & FTRACE_ITER_MOD)
3615		return t_mod_next(m, pos);
3616
3617	if (iter->flags & FTRACE_ITER_PRINTALL) {
3618		/* next must increment pos, and t_probe_start does not */
3619		(*pos)++;
3620		return t_mod_start(m, &l);
3621	}
3622
3623	ret = t_func_next(m, pos);
3624
3625	if (!ret)
3626		return t_mod_start(m, &l);
3627
3628	return ret;
3629}
3630
3631static void reset_iter_read(struct ftrace_iterator *iter)
3632{
3633	iter->pos = 0;
3634	iter->func_pos = 0;
3635	iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3636}
3637
3638static void *t_start(struct seq_file *m, loff_t *pos)
3639{
3640	struct ftrace_iterator *iter = m->private;
3641	void *p = NULL;
3642	loff_t l;
3643
3644	mutex_lock(&ftrace_lock);
3645
3646	if (unlikely(ftrace_disabled))
3647		return NULL;
3648
3649	/*
3650	 * If an lseek was done, then reset and start from beginning.
3651	 */
3652	if (*pos < iter->pos)
3653		reset_iter_read(iter);
3654
3655	/*
3656	 * For set_ftrace_filter reading, if we have the filter
3657	 * off, we can short cut and just print out that all
3658	 * functions are enabled.
3659	 */
3660	if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3661	    ftrace_hash_empty(iter->hash)) {
3662		iter->func_pos = 1; /* Account for the message */
3663		if (*pos > 0)
3664			return t_mod_start(m, pos);
3665		iter->flags |= FTRACE_ITER_PRINTALL;
3666		/* reset in case of seek/pread */
3667		iter->flags &= ~FTRACE_ITER_PROBE;
3668		return iter;
3669	}
3670
3671	if (iter->flags & FTRACE_ITER_MOD)
3672		return t_mod_start(m, pos);
3673
3674	/*
3675	 * Unfortunately, we need to restart at ftrace_pages_start
3676	 * every time we let go of the ftrace_mutex. This is because
3677	 * those pointers can change without the lock.
3678	 */
3679	iter->pg = ftrace_pages_start;
3680	iter->idx = 0;
3681	for (l = 0; l <= *pos; ) {
3682		p = t_func_next(m, &l);
3683		if (!p)
3684			break;
3685	}
3686
3687	if (!p)
3688		return t_mod_start(m, pos);
3689
3690	return iter;
3691}
3692
3693static void t_stop(struct seq_file *m, void *p)
3694{
3695	mutex_unlock(&ftrace_lock);
3696}
3697
3698void * __weak
3699arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3700{
3701	return NULL;
3702}
3703
3704static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3705				struct dyn_ftrace *rec)
3706{
3707	void *ptr;
3708
3709	ptr = arch_ftrace_trampoline_func(ops, rec);
3710	if (ptr)
3711		seq_printf(m, " ->%pS", ptr);
3712}
3713
3714#ifdef FTRACE_MCOUNT_MAX_OFFSET
3715/*
3716 * Weak functions can still have an mcount/fentry that is saved in
3717 * the __mcount_loc section. These can be detected by having a
3718 * symbol offset of greater than FTRACE_MCOUNT_MAX_OFFSET, as the
3719 * symbol found by kallsyms is not the function that the mcount/fentry
3720 * is part of. The offset is much greater in these cases.
3721 *
3722 * Test the record to make sure that the ip points to a valid kallsyms
3723 * and if not, mark it disabled.
3724 */
3725static int test_for_valid_rec(struct dyn_ftrace *rec)
3726{
3727	char str[KSYM_SYMBOL_LEN];
3728	unsigned long offset;
3729	const char *ret;
3730
3731	ret = kallsyms_lookup(rec->ip, NULL, &offset, NULL, str);
3732
3733	/* Weak functions can cause invalid addresses */
3734	if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3735		rec->flags |= FTRACE_FL_DISABLED;
3736		return 0;
3737	}
3738	return 1;
3739}
3740
3741static struct workqueue_struct *ftrace_check_wq __initdata;
3742static struct work_struct ftrace_check_work __initdata;
3743
3744/*
3745 * Scan all the mcount/fentry entries to make sure they are valid.
3746 */
3747static __init void ftrace_check_work_func(struct work_struct *work)
3748{
3749	struct ftrace_page *pg;
3750	struct dyn_ftrace *rec;
3751
3752	mutex_lock(&ftrace_lock);
3753	do_for_each_ftrace_rec(pg, rec) {
3754		test_for_valid_rec(rec);
3755	} while_for_each_ftrace_rec();
3756	mutex_unlock(&ftrace_lock);
3757}
3758
3759static int __init ftrace_check_for_weak_functions(void)
3760{
3761	INIT_WORK(&ftrace_check_work, ftrace_check_work_func);
3762
3763	ftrace_check_wq = alloc_workqueue("ftrace_check_wq", WQ_UNBOUND, 0);
3764
3765	queue_work(ftrace_check_wq, &ftrace_check_work);
3766	return 0;
3767}
3768
3769static int __init ftrace_check_sync(void)
3770{
3771	/* Make sure the ftrace_check updates are finished */
3772	if (ftrace_check_wq)
3773		destroy_workqueue(ftrace_check_wq);
3774	return 0;
3775}
3776
3777late_initcall_sync(ftrace_check_sync);
3778subsys_initcall(ftrace_check_for_weak_functions);
3779
3780static int print_rec(struct seq_file *m, unsigned long ip)
3781{
3782	unsigned long offset;
3783	char str[KSYM_SYMBOL_LEN];
3784	char *modname;
3785	const char *ret;
3786
3787	ret = kallsyms_lookup(ip, NULL, &offset, &modname, str);
3788	/* Weak functions can cause invalid addresses */
3789	if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3790		snprintf(str, KSYM_SYMBOL_LEN, "%s_%ld",
3791			 FTRACE_INVALID_FUNCTION, offset);
3792		ret = NULL;
3793	}
3794
3795	seq_puts(m, str);
3796	if (modname)
3797		seq_printf(m, " [%s]", modname);
3798	return ret == NULL ? -1 : 0;
3799}
3800#else
3801static inline int test_for_valid_rec(struct dyn_ftrace *rec)
3802{
3803	return 1;
3804}
3805
3806static inline int print_rec(struct seq_file *m, unsigned long ip)
3807{
3808	seq_printf(m, "%ps", (void *)ip);
3809	return 0;
3810}
3811#endif
3812
3813static int t_show(struct seq_file *m, void *v)
3814{
3815	struct ftrace_iterator *iter = m->private;
3816	struct dyn_ftrace *rec;
3817
3818	if (iter->flags & FTRACE_ITER_PROBE)
3819		return t_probe_show(m, iter);
3820
3821	if (iter->flags & FTRACE_ITER_MOD)
3822		return t_mod_show(m, iter);
3823
3824	if (iter->flags & FTRACE_ITER_PRINTALL) {
3825		if (iter->flags & FTRACE_ITER_NOTRACE)
3826			seq_puts(m, "#### no functions disabled ####\n");
3827		else
3828			seq_puts(m, "#### all functions enabled ####\n");
3829		return 0;
3830	}
3831
3832	rec = iter->func;
3833
3834	if (!rec)
3835		return 0;
3836
3837	if (iter->flags & FTRACE_ITER_ADDRS)
3838		seq_printf(m, "%lx ", rec->ip);
3839
3840	if (print_rec(m, rec->ip)) {
3841		/* This should only happen when a rec is disabled */
3842		WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
3843		seq_putc(m, '\n');
3844		return 0;
3845	}
3846
3847	if (iter->flags & (FTRACE_ITER_ENABLED | FTRACE_ITER_TOUCHED)) {
3848		struct ftrace_ops *ops;
3849
3850		seq_printf(m, " (%ld)%s%s%s%s%s",
3851			   ftrace_rec_count(rec),
3852			   rec->flags & FTRACE_FL_REGS ? " R" : "  ",
3853			   rec->flags & FTRACE_FL_IPMODIFY ? " I" : "  ",
3854			   rec->flags & FTRACE_FL_DIRECT ? " D" : "  ",
3855			   rec->flags & FTRACE_FL_CALL_OPS ? " O" : "  ",
3856			   rec->flags & FTRACE_FL_MODIFIED ? " M " : "   ");
3857		if (rec->flags & FTRACE_FL_TRAMP_EN) {
3858			ops = ftrace_find_tramp_ops_any(rec);
3859			if (ops) {
3860				do {
3861					seq_printf(m, "\ttramp: %pS (%pS)",
3862						   (void *)ops->trampoline,
3863						   (void *)ops->func);
3864					add_trampoline_func(m, ops, rec);
3865					ops = ftrace_find_tramp_ops_next(rec, ops);
3866				} while (ops);
3867			} else
3868				seq_puts(m, "\ttramp: ERROR!");
3869		} else {
3870			add_trampoline_func(m, NULL, rec);
3871		}
3872		if (rec->flags & FTRACE_FL_CALL_OPS_EN) {
3873			ops = ftrace_find_unique_ops(rec);
3874			if (ops) {
3875				seq_printf(m, "\tops: %pS (%pS)",
3876					   ops, ops->func);
3877			} else {
3878				seq_puts(m, "\tops: ERROR!");
3879			}
3880		}
3881		if (rec->flags & FTRACE_FL_DIRECT) {
3882			unsigned long direct;
3883
3884			direct = ftrace_find_rec_direct(rec->ip);
3885			if (direct)
3886				seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3887		}
3888	}
3889
3890	seq_putc(m, '\n');
3891
3892	return 0;
3893}
3894
3895static const struct seq_operations show_ftrace_seq_ops = {
3896	.start = t_start,
3897	.next = t_next,
3898	.stop = t_stop,
3899	.show = t_show,
3900};
3901
3902static int
3903ftrace_avail_open(struct inode *inode, struct file *file)
3904{
3905	struct ftrace_iterator *iter;
3906	int ret;
3907
3908	ret = security_locked_down(LOCKDOWN_TRACEFS);
3909	if (ret)
3910		return ret;
3911
3912	if (unlikely(ftrace_disabled))
3913		return -ENODEV;
3914
3915	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3916	if (!iter)
3917		return -ENOMEM;
3918
3919	iter->pg = ftrace_pages_start;
3920	iter->ops = &global_ops;
3921
3922	return 0;
3923}
3924
3925static int
3926ftrace_enabled_open(struct inode *inode, struct file *file)
3927{
3928	struct ftrace_iterator *iter;
3929
3930	/*
3931	 * This shows us what functions are currently being
3932	 * traced and by what. Not sure if we want lockdown
3933	 * to hide such critical information for an admin.
3934	 * Although, perhaps it can show information we don't
3935	 * want people to see, but if something is tracing
3936	 * something, we probably want to know about it.
3937	 */
3938
3939	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3940	if (!iter)
3941		return -ENOMEM;
3942
3943	iter->pg = ftrace_pages_start;
3944	iter->flags = FTRACE_ITER_ENABLED;
3945	iter->ops = &global_ops;
3946
3947	return 0;
3948}
3949
3950static int
3951ftrace_touched_open(struct inode *inode, struct file *file)
3952{
3953	struct ftrace_iterator *iter;
3954
3955	/*
3956	 * This shows us what functions have ever been enabled
3957	 * (traced, direct, patched, etc). Not sure if we want lockdown
3958	 * to hide such critical information for an admin.
3959	 * Although, perhaps it can show information we don't
3960	 * want people to see, but if something had traced
3961	 * something, we probably want to know about it.
3962	 */
3963
3964	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3965	if (!iter)
3966		return -ENOMEM;
3967
3968	iter->pg = ftrace_pages_start;
3969	iter->flags = FTRACE_ITER_TOUCHED;
3970	iter->ops = &global_ops;
3971
3972	return 0;
3973}
3974
3975static int
3976ftrace_avail_addrs_open(struct inode *inode, struct file *file)
3977{
3978	struct ftrace_iterator *iter;
3979	int ret;
3980
3981	ret = security_locked_down(LOCKDOWN_TRACEFS);
3982	if (ret)
3983		return ret;
3984
3985	if (unlikely(ftrace_disabled))
3986		return -ENODEV;
3987
3988	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3989	if (!iter)
3990		return -ENOMEM;
3991
3992	iter->pg = ftrace_pages_start;
3993	iter->flags = FTRACE_ITER_ADDRS;
3994	iter->ops = &global_ops;
3995
3996	return 0;
3997}
3998
3999/**
4000 * ftrace_regex_open - initialize function tracer filter files
4001 * @ops: The ftrace_ops that hold the hash filters
4002 * @flag: The type of filter to process
4003 * @inode: The inode, usually passed in to your open routine
4004 * @file: The file, usually passed in to your open routine
4005 *
4006 * ftrace_regex_open() initializes the filter files for the
4007 * @ops. Depending on @flag it may process the filter hash or
4008 * the notrace hash of @ops. With this called from the open
4009 * routine, you can use ftrace_filter_write() for the write
4010 * routine if @flag has FTRACE_ITER_FILTER set, or
4011 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
4012 * tracing_lseek() should be used as the lseek routine, and
4013 * release must call ftrace_regex_release().
4014 *
4015 * Returns: 0 on success or a negative errno value on failure
4016 */
4017int
4018ftrace_regex_open(struct ftrace_ops *ops, int flag,
4019		  struct inode *inode, struct file *file)
4020{
4021	struct ftrace_iterator *iter;
4022	struct ftrace_hash *hash;
4023	struct list_head *mod_head;
4024	struct trace_array *tr = ops->private;
4025	int ret = -ENOMEM;
4026
4027	ftrace_ops_init(ops);
4028
4029	if (unlikely(ftrace_disabled))
4030		return -ENODEV;
4031
4032	if (tracing_check_open_get_tr(tr))
4033		return -ENODEV;
4034
4035	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
4036	if (!iter)
4037		goto out;
4038
4039	if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
4040		goto out;
4041
4042	iter->ops = ops;
4043	iter->flags = flag;
4044	iter->tr = tr;
4045
4046	mutex_lock(&ops->func_hash->regex_lock);
4047
4048	if (flag & FTRACE_ITER_NOTRACE) {
4049		hash = ops->func_hash->notrace_hash;
4050		mod_head = tr ? &tr->mod_notrace : NULL;
4051	} else {
4052		hash = ops->func_hash->filter_hash;
4053		mod_head = tr ? &tr->mod_trace : NULL;
4054	}
4055
4056	iter->mod_list = mod_head;
4057
4058	if (file->f_mode & FMODE_WRITE) {
4059		const int size_bits = FTRACE_HASH_DEFAULT_BITS;
4060
4061		if (file->f_flags & O_TRUNC) {
4062			iter->hash = alloc_ftrace_hash(size_bits);
4063			clear_ftrace_mod_list(mod_head);
4064	        } else {
4065			iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
4066		}
4067
4068		if (!iter->hash) {
4069			trace_parser_put(&iter->parser);
4070			goto out_unlock;
4071		}
4072	} else
4073		iter->hash = hash;
4074
4075	ret = 0;
4076
4077	if (file->f_mode & FMODE_READ) {
4078		iter->pg = ftrace_pages_start;
4079
4080		ret = seq_open(file, &show_ftrace_seq_ops);
4081		if (!ret) {
4082			struct seq_file *m = file->private_data;
4083			m->private = iter;
4084		} else {
4085			/* Failed */
4086			free_ftrace_hash(iter->hash);
4087			trace_parser_put(&iter->parser);
4088		}
4089	} else
4090		file->private_data = iter;
4091
4092 out_unlock:
4093	mutex_unlock(&ops->func_hash->regex_lock);
4094
4095 out:
4096	if (ret) {
4097		kfree(iter);
4098		if (tr)
4099			trace_array_put(tr);
4100	}
4101
4102	return ret;
4103}
4104
4105static int
4106ftrace_filter_open(struct inode *inode, struct file *file)
4107{
4108	struct ftrace_ops *ops = inode->i_private;
4109
4110	/* Checks for tracefs lockdown */
4111	return ftrace_regex_open(ops,
4112			FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
4113			inode, file);
4114}
4115
4116static int
4117ftrace_notrace_open(struct inode *inode, struct file *file)
4118{
4119	struct ftrace_ops *ops = inode->i_private;
4120
4121	/* Checks for tracefs lockdown */
4122	return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
4123				 inode, file);
4124}
4125
4126/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
4127struct ftrace_glob {
4128	char *search;
4129	unsigned len;
4130	int type;
4131};
4132
4133/*
4134 * If symbols in an architecture don't correspond exactly to the user-visible
4135 * name of what they represent, it is possible to define this function to
4136 * perform the necessary adjustments.
4137*/
4138char * __weak arch_ftrace_match_adjust(char *str, const char *search)
4139{
4140	return str;
4141}
4142
4143static int ftrace_match(char *str, struct ftrace_glob *g)
4144{
4145	int matched = 0;
4146	int slen;
4147
4148	str = arch_ftrace_match_adjust(str, g->search);
4149
4150	switch (g->type) {
4151	case MATCH_FULL:
4152		if (strcmp(str, g->search) == 0)
4153			matched = 1;
4154		break;
4155	case MATCH_FRONT_ONLY:
4156		if (strncmp(str, g->search, g->len) == 0)
4157			matched = 1;
4158		break;
4159	case MATCH_MIDDLE_ONLY:
4160		if (strstr(str, g->search))
4161			matched = 1;
4162		break;
4163	case MATCH_END_ONLY:
4164		slen = strlen(str);
4165		if (slen >= g->len &&
4166		    memcmp(str + slen - g->len, g->search, g->len) == 0)
4167			matched = 1;
4168		break;
4169	case MATCH_GLOB:
4170		if (glob_match(g->search, str))
4171			matched = 1;
4172		break;
4173	}
4174
4175	return matched;
4176}
4177
4178static int
4179enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
4180{
4181	struct ftrace_func_entry *entry;
4182	int ret = 0;
4183
4184	entry = ftrace_lookup_ip(hash, rec->ip);
4185	if (clear_filter) {
4186		/* Do nothing if it doesn't exist */
4187		if (!entry)
4188			return 0;
4189
4190		free_hash_entry(hash, entry);
4191	} else {
4192		/* Do nothing if it exists */
4193		if (entry)
4194			return 0;
4195		if (add_hash_entry(hash, rec->ip) == NULL)
4196			ret = -ENOMEM;
4197	}
4198	return ret;
4199}
4200
4201static int
4202add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
4203		 int clear_filter)
4204{
4205	long index = simple_strtoul(func_g->search, NULL, 0);
4206	struct ftrace_page *pg;
4207	struct dyn_ftrace *rec;
4208
4209	/* The index starts at 1 */
4210	if (--index < 0)
4211		return 0;
4212
4213	do_for_each_ftrace_rec(pg, rec) {
4214		if (pg->index <= index) {
4215			index -= pg->index;
4216			/* this is a double loop, break goes to the next page */
4217			break;
4218		}
4219		rec = &pg->records[index];
4220		enter_record(hash, rec, clear_filter);
4221		return 1;
4222	} while_for_each_ftrace_rec();
4223	return 0;
4224}
4225
4226#ifdef FTRACE_MCOUNT_MAX_OFFSET
4227static int lookup_ip(unsigned long ip, char **modname, char *str)
4228{
4229	unsigned long offset;
4230
4231	kallsyms_lookup(ip, NULL, &offset, modname, str);
4232	if (offset > FTRACE_MCOUNT_MAX_OFFSET)
4233		return -1;
4234	return 0;
4235}
4236#else
4237static int lookup_ip(unsigned long ip, char **modname, char *str)
4238{
4239	kallsyms_lookup(ip, NULL, NULL, modname, str);
4240	return 0;
4241}
4242#endif
4243
4244static int
4245ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
4246		struct ftrace_glob *mod_g, int exclude_mod)
4247{
4248	char str[KSYM_SYMBOL_LEN];
4249	char *modname;
4250
4251	if (lookup_ip(rec->ip, &modname, str)) {
4252		/* This should only happen when a rec is disabled */
4253		WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
4254			     !(rec->flags & FTRACE_FL_DISABLED));
4255		return 0;
4256	}
4257
4258	if (mod_g) {
4259		int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
4260
4261		/* blank module name to match all modules */
4262		if (!mod_g->len) {
4263			/* blank module globbing: modname xor exclude_mod */
4264			if (!exclude_mod != !modname)
4265				goto func_match;
4266			return 0;
4267		}
4268
4269		/*
4270		 * exclude_mod is set to trace everything but the given
4271		 * module. If it is set and the module matches, then
4272		 * return 0. If it is not set, and the module doesn't match
4273		 * also return 0. Otherwise, check the function to see if
4274		 * that matches.
4275		 */
4276		if (!mod_matches == !exclude_mod)
4277			return 0;
4278func_match:
4279		/* blank search means to match all funcs in the mod */
4280		if (!func_g->len)
4281			return 1;
4282	}
4283
4284	return ftrace_match(str, func_g);
4285}
4286
4287static int
4288match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4289{
4290	struct ftrace_page *pg;
4291	struct dyn_ftrace *rec;
4292	struct ftrace_glob func_g = { .type = MATCH_FULL };
4293	struct ftrace_glob mod_g = { .type = MATCH_FULL };
4294	struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4295	int exclude_mod = 0;
4296	int found = 0;
4297	int ret;
4298	int clear_filter = 0;
4299
4300	if (func) {
4301		func_g.type = filter_parse_regex(func, len, &func_g.search,
4302						 &clear_filter);
4303		func_g.len = strlen(func_g.search);
4304	}
4305
4306	if (mod) {
4307		mod_g.type = filter_parse_regex(mod, strlen(mod),
4308				&mod_g.search, &exclude_mod);
4309		mod_g.len = strlen(mod_g.search);
4310	}
4311
4312	mutex_lock(&ftrace_lock);
4313
4314	if (unlikely(ftrace_disabled))
4315		goto out_unlock;
4316
4317	if (func_g.type == MATCH_INDEX) {
4318		found = add_rec_by_index(hash, &func_g, clear_filter);
4319		goto out_unlock;
4320	}
4321
4322	do_for_each_ftrace_rec(pg, rec) {
4323
4324		if (rec->flags & FTRACE_FL_DISABLED)
4325			continue;
4326
4327		if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4328			ret = enter_record(hash, rec, clear_filter);
4329			if (ret < 0) {
4330				found = ret;
4331				goto out_unlock;
4332			}
4333			found = 1;
4334		}
4335		cond_resched();
4336	} while_for_each_ftrace_rec();
4337 out_unlock:
4338	mutex_unlock(&ftrace_lock);
4339
4340	return found;
4341}
4342
4343static int
4344ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4345{
4346	return match_records(hash, buff, len, NULL);
4347}
4348
4349static void ftrace_ops_update_code(struct ftrace_ops *ops,
4350				   struct ftrace_ops_hash *old_hash)
4351{
4352	struct ftrace_ops *op;
4353
4354	if (!ftrace_enabled)
4355		return;
4356
4357	if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4358		ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4359		return;
4360	}
4361
4362	/*
4363	 * If this is the shared global_ops filter, then we need to
4364	 * check if there is another ops that shares it, is enabled.
4365	 * If so, we still need to run the modify code.
4366	 */
4367	if (ops->func_hash != &global_ops.local_hash)
4368		return;
4369
4370	do_for_each_ftrace_op(op, ftrace_ops_list) {
4371		if (op->func_hash == &global_ops.local_hash &&
4372		    op->flags & FTRACE_OPS_FL_ENABLED) {
4373			ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4374			/* Only need to do this once */
4375			return;
4376		}
4377	} while_for_each_ftrace_op(op);
4378}
4379
4380static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4381					   struct ftrace_hash **orig_hash,
4382					   struct ftrace_hash *hash,
4383					   int enable)
4384{
4385	struct ftrace_ops_hash old_hash_ops;
4386	struct ftrace_hash *old_hash;
4387	int ret;
4388
4389	old_hash = *orig_hash;
4390	old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4391	old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4392	ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4393	if (!ret) {
4394		ftrace_ops_update_code(ops, &old_hash_ops);
4395		free_ftrace_hash_rcu(old_hash);
4396	}
4397	return ret;
4398}
4399
4400static bool module_exists(const char *module)
4401{
4402	/* All modules have the symbol __this_module */
4403	static const char this_mod[] = "__this_module";
4404	char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4405	unsigned long val;
4406	int n;
4407
4408	n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4409
4410	if (n > sizeof(modname) - 1)
4411		return false;
4412
4413	val = module_kallsyms_lookup_name(modname);
4414	return val != 0;
4415}
4416
4417static int cache_mod(struct trace_array *tr,
4418		     const char *func, char *module, int enable)
4419{
4420	struct ftrace_mod_load *ftrace_mod, *n;
4421	struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4422	int ret;
4423
4424	mutex_lock(&ftrace_lock);
4425
4426	/* We do not cache inverse filters */
4427	if (func[0] == '!') {
4428		func++;
4429		ret = -EINVAL;
4430
4431		/* Look to remove this hash */
4432		list_for_each_entry_safe(ftrace_mod, n, head, list) {
4433			if (strcmp(ftrace_mod->module, module) != 0)
4434				continue;
4435
4436			/* no func matches all */
4437			if (strcmp(func, "*") == 0 ||
4438			    (ftrace_mod->func &&
4439			     strcmp(ftrace_mod->func, func) == 0)) {
4440				ret = 0;
4441				free_ftrace_mod(ftrace_mod);
4442				continue;
4443			}
4444		}
4445		goto out;
4446	}
4447
4448	ret = -EINVAL;
4449	/* We only care about modules that have not been loaded yet */
4450	if (module_exists(module))
4451		goto out;
4452
4453	/* Save this string off, and execute it when the module is loaded */
4454	ret = ftrace_add_mod(tr, func, module, enable);
4455 out:
4456	mutex_unlock(&ftrace_lock);
4457
4458	return ret;
4459}
4460
4461static int
4462ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4463		 int reset, int enable);
4464
4465#ifdef CONFIG_MODULES
4466static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4467			     char *mod, bool enable)
4468{
4469	struct ftrace_mod_load *ftrace_mod, *n;
4470	struct ftrace_hash **orig_hash, *new_hash;
4471	LIST_HEAD(process_mods);
4472	char *func;
4473
4474	mutex_lock(&ops->func_hash->regex_lock);
4475
4476	if (enable)
4477		orig_hash = &ops->func_hash->filter_hash;
4478	else
4479		orig_hash = &ops->func_hash->notrace_hash;
4480
4481	new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4482					      *orig_hash);
4483	if (!new_hash)
4484		goto out; /* warn? */
4485
4486	mutex_lock(&ftrace_lock);
4487
4488	list_for_each_entry_safe(ftrace_mod, n, head, list) {
4489
4490		if (strcmp(ftrace_mod->module, mod) != 0)
4491			continue;
4492
4493		if (ftrace_mod->func)
4494			func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4495		else
4496			func = kstrdup("*", GFP_KERNEL);
4497
4498		if (!func) /* warn? */
4499			continue;
4500
4501		list_move(&ftrace_mod->list, &process_mods);
4502
4503		/* Use the newly allocated func, as it may be "*" */
4504		kfree(ftrace_mod->func);
4505		ftrace_mod->func = func;
4506	}
4507
4508	mutex_unlock(&ftrace_lock);
4509
4510	list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4511
4512		func = ftrace_mod->func;
4513
4514		/* Grabs ftrace_lock, which is why we have this extra step */
4515		match_records(new_hash, func, strlen(func), mod);
4516		free_ftrace_mod(ftrace_mod);
4517	}
4518
4519	if (enable && list_empty(head))
4520		new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4521
4522	mutex_lock(&ftrace_lock);
4523
4524	ftrace_hash_move_and_update_ops(ops, orig_hash,
4525					      new_hash, enable);
4526	mutex_unlock(&ftrace_lock);
4527
4528 out:
4529	mutex_unlock(&ops->func_hash->regex_lock);
4530
4531	free_ftrace_hash(new_hash);
4532}
4533
4534static void process_cached_mods(const char *mod_name)
4535{
4536	struct trace_array *tr;
4537	char *mod;
4538
4539	mod = kstrdup(mod_name, GFP_KERNEL);
4540	if (!mod)
4541		return;
4542
4543	mutex_lock(&trace_types_lock);
4544	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4545		if (!list_empty(&tr->mod_trace))
4546			process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4547		if (!list_empty(&tr->mod_notrace))
4548			process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4549	}
4550	mutex_unlock(&trace_types_lock);
4551
4552	kfree(mod);
4553}
4554#endif
4555
4556/*
4557 * We register the module command as a template to show others how
4558 * to register the a command as well.
4559 */
4560
4561static int
4562ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4563		    char *func_orig, char *cmd, char *module, int enable)
4564{
4565	char *func;
4566	int ret;
4567
4568	/* match_records() modifies func, and we need the original */
4569	func = kstrdup(func_orig, GFP_KERNEL);
4570	if (!func)
4571		return -ENOMEM;
4572
4573	/*
4574	 * cmd == 'mod' because we only registered this func
4575	 * for the 'mod' ftrace_func_command.
4576	 * But if you register one func with multiple commands,
4577	 * you can tell which command was used by the cmd
4578	 * parameter.
4579	 */
4580	ret = match_records(hash, func, strlen(func), module);
4581	kfree(func);
4582
4583	if (!ret)
4584		return cache_mod(tr, func_orig, module, enable);
4585	if (ret < 0)
4586		return ret;
4587	return 0;
4588}
4589
4590static struct ftrace_func_command ftrace_mod_cmd = {
4591	.name			= "mod",
4592	.func			= ftrace_mod_callback,
4593};
4594
4595static int __init ftrace_mod_cmd_init(void)
4596{
4597	return register_ftrace_command(&ftrace_mod_cmd);
4598}
4599core_initcall(ftrace_mod_cmd_init);
4600
4601static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4602				      struct ftrace_ops *op, struct ftrace_regs *fregs)
4603{
4604	struct ftrace_probe_ops *probe_ops;
4605	struct ftrace_func_probe *probe;
4606
4607	probe = container_of(op, struct ftrace_func_probe, ops);
4608	probe_ops = probe->probe_ops;
4609
4610	/*
4611	 * Disable preemption for these calls to prevent a RCU grace
4612	 * period. This syncs the hash iteration and freeing of items
4613	 * on the hash. rcu_read_lock is too dangerous here.
4614	 */
4615	preempt_disable_notrace();
4616	probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4617	preempt_enable_notrace();
4618}
4619
4620struct ftrace_func_map {
4621	struct ftrace_func_entry	entry;
4622	void				*data;
4623};
4624
4625struct ftrace_func_mapper {
4626	struct ftrace_hash		hash;
4627};
4628
4629/**
4630 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4631 *
4632 * Returns: a ftrace_func_mapper descriptor that can be used to map ips to data.
4633 */
4634struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4635{
4636	struct ftrace_hash *hash;
4637
4638	/*
4639	 * The mapper is simply a ftrace_hash, but since the entries
4640	 * in the hash are not ftrace_func_entry type, we define it
4641	 * as a separate structure.
4642	 */
4643	hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4644	return (struct ftrace_func_mapper *)hash;
4645}
4646
4647/**
4648 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4649 * @mapper: The mapper that has the ip maps
4650 * @ip: the instruction pointer to find the data for
4651 *
4652 * Returns: the data mapped to @ip if found otherwise NULL. The return
4653 * is actually the address of the mapper data pointer. The address is
4654 * returned for use cases where the data is no bigger than a long, and
4655 * the user can use the data pointer as its data instead of having to
4656 * allocate more memory for the reference.
4657 */
4658void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4659				  unsigned long ip)
4660{
4661	struct ftrace_func_entry *entry;
4662	struct ftrace_func_map *map;
4663
4664	entry = ftrace_lookup_ip(&mapper->hash, ip);
4665	if (!entry)
4666		return NULL;
4667
4668	map = (struct ftrace_func_map *)entry;
4669	return &map->data;
4670}
4671
4672/**
4673 * ftrace_func_mapper_add_ip - Map some data to an ip
4674 * @mapper: The mapper that has the ip maps
4675 * @ip: The instruction pointer address to map @data to
4676 * @data: The data to map to @ip
4677 *
4678 * Returns: 0 on success otherwise an error.
4679 */
4680int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4681			      unsigned long ip, void *data)
4682{
4683	struct ftrace_func_entry *entry;
4684	struct ftrace_func_map *map;
4685
4686	entry = ftrace_lookup_ip(&mapper->hash, ip);
4687	if (entry)
4688		return -EBUSY;
4689
4690	map = kmalloc(sizeof(*map), GFP_KERNEL);
4691	if (!map)
4692		return -ENOMEM;
4693
4694	map->entry.ip = ip;
4695	map->data = data;
4696
4697	__add_hash_entry(&mapper->hash, &map->entry);
4698
4699	return 0;
4700}
4701
4702/**
4703 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4704 * @mapper: The mapper that has the ip maps
4705 * @ip: The instruction pointer address to remove the data from
4706 *
4707 * Returns: the data if it is found, otherwise NULL.
4708 * Note, if the data pointer is used as the data itself, (see
4709 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4710 * if the data pointer was set to zero.
4711 */
4712void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4713				   unsigned long ip)
4714{
4715	struct ftrace_func_entry *entry;
4716	struct ftrace_func_map *map;
4717	void *data;
4718
4719	entry = ftrace_lookup_ip(&mapper->hash, ip);
4720	if (!entry)
4721		return NULL;
4722
4723	map = (struct ftrace_func_map *)entry;
4724	data = map->data;
4725
4726	remove_hash_entry(&mapper->hash, entry);
4727	kfree(entry);
4728
4729	return data;
4730}
4731
4732/**
4733 * free_ftrace_func_mapper - free a mapping of ips and data
4734 * @mapper: The mapper that has the ip maps
4735 * @free_func: A function to be called on each data item.
4736 *
4737 * This is used to free the function mapper. The @free_func is optional
4738 * and can be used if the data needs to be freed as well.
4739 */
4740void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4741			     ftrace_mapper_func free_func)
4742{
4743	struct ftrace_func_entry *entry;
4744	struct ftrace_func_map *map;
4745	struct hlist_head *hhd;
4746	int size, i;
4747
4748	if (!mapper)
4749		return;
4750
4751	if (free_func && mapper->hash.count) {
4752		size = 1 << mapper->hash.size_bits;
4753		for (i = 0; i < size; i++) {
4754			hhd = &mapper->hash.buckets[i];
4755			hlist_for_each_entry(entry, hhd, hlist) {
4756				map = (struct ftrace_func_map *)entry;
4757				free_func(map);
4758			}
4759		}
4760	}
4761	free_ftrace_hash(&mapper->hash);
4762}
4763
4764static void release_probe(struct ftrace_func_probe *probe)
4765{
4766	struct ftrace_probe_ops *probe_ops;
4767
4768	mutex_lock(&ftrace_lock);
4769
4770	WARN_ON(probe->ref <= 0);
4771
4772	/* Subtract the ref that was used to protect this instance */
4773	probe->ref--;
4774
4775	if (!probe->ref) {
4776		probe_ops = probe->probe_ops;
4777		/*
4778		 * Sending zero as ip tells probe_ops to free
4779		 * the probe->data itself
4780		 */
4781		if (probe_ops->free)
4782			probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4783		list_del(&probe->list);
4784		kfree(probe);
4785	}
4786	mutex_unlock(&ftrace_lock);
4787}
4788
4789static void acquire_probe_locked(struct ftrace_func_probe *probe)
4790{
4791	/*
4792	 * Add one ref to keep it from being freed when releasing the
4793	 * ftrace_lock mutex.
4794	 */
4795	probe->ref++;
4796}
4797
4798int
4799register_ftrace_function_probe(char *glob, struct trace_array *tr,
4800			       struct ftrace_probe_ops *probe_ops,
4801			       void *data)
4802{
4803	struct ftrace_func_probe *probe = NULL, *iter;
4804	struct ftrace_func_entry *entry;
4805	struct ftrace_hash **orig_hash;
4806	struct ftrace_hash *old_hash;
4807	struct ftrace_hash *hash;
4808	int count = 0;
4809	int size;
4810	int ret;
4811	int i;
4812
4813	if (WARN_ON(!tr))
4814		return -EINVAL;
4815
4816	/* We do not support '!' for function probes */
4817	if (WARN_ON(glob[0] == '!'))
4818		return -EINVAL;
4819
4820
4821	mutex_lock(&ftrace_lock);
4822	/* Check if the probe_ops is already registered */
4823	list_for_each_entry(iter, &tr->func_probes, list) {
4824		if (iter->probe_ops == probe_ops) {
4825			probe = iter;
4826			break;
4827		}
4828	}
4829	if (!probe) {
4830		probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4831		if (!probe) {
4832			mutex_unlock(&ftrace_lock);
4833			return -ENOMEM;
4834		}
4835		probe->probe_ops = probe_ops;
4836		probe->ops.func = function_trace_probe_call;
4837		probe->tr = tr;
4838		ftrace_ops_init(&probe->ops);
4839		list_add(&probe->list, &tr->func_probes);
4840	}
4841
4842	acquire_probe_locked(probe);
4843
4844	mutex_unlock(&ftrace_lock);
4845
4846	/*
4847	 * Note, there's a small window here that the func_hash->filter_hash
4848	 * may be NULL or empty. Need to be careful when reading the loop.
4849	 */
4850	mutex_lock(&probe->ops.func_hash->regex_lock);
4851
4852	orig_hash = &probe->ops.func_hash->filter_hash;
4853	old_hash = *orig_hash;
4854	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4855
4856	if (!hash) {
4857		ret = -ENOMEM;
4858		goto out;
4859	}
4860
4861	ret = ftrace_match_records(hash, glob, strlen(glob));
4862
4863	/* Nothing found? */
4864	if (!ret)
4865		ret = -EINVAL;
4866
4867	if (ret < 0)
4868		goto out;
4869
4870	size = 1 << hash->size_bits;
4871	for (i = 0; i < size; i++) {
4872		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4873			if (ftrace_lookup_ip(old_hash, entry->ip))
4874				continue;
4875			/*
4876			 * The caller might want to do something special
4877			 * for each function we find. We call the callback
4878			 * to give the caller an opportunity to do so.
4879			 */
4880			if (probe_ops->init) {
4881				ret = probe_ops->init(probe_ops, tr,
4882						      entry->ip, data,
4883						      &probe->data);
4884				if (ret < 0) {
4885					if (probe_ops->free && count)
4886						probe_ops->free(probe_ops, tr,
4887								0, probe->data);
4888					probe->data = NULL;
4889					goto out;
4890				}
4891			}
4892			count++;
4893		}
4894	}
4895
4896	mutex_lock(&ftrace_lock);
4897
4898	if (!count) {
4899		/* Nothing was added? */
4900		ret = -EINVAL;
4901		goto out_unlock;
4902	}
4903
4904	ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4905					      hash, 1);
4906	if (ret < 0)
4907		goto err_unlock;
4908
4909	/* One ref for each new function traced */
4910	probe->ref += count;
4911
4912	if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4913		ret = ftrace_startup(&probe->ops, 0);
4914
4915 out_unlock:
4916	mutex_unlock(&ftrace_lock);
4917
4918	if (!ret)
4919		ret = count;
4920 out:
4921	mutex_unlock(&probe->ops.func_hash->regex_lock);
4922	free_ftrace_hash(hash);
4923
4924	release_probe(probe);
4925
4926	return ret;
4927
4928 err_unlock:
4929	if (!probe_ops->free || !count)
4930		goto out_unlock;
4931
4932	/* Failed to do the move, need to call the free functions */
4933	for (i = 0; i < size; i++) {
4934		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4935			if (ftrace_lookup_ip(old_hash, entry->ip))
4936				continue;
4937			probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4938		}
4939	}
4940	goto out_unlock;
4941}
4942
4943int
4944unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4945				      struct ftrace_probe_ops *probe_ops)
4946{
4947	struct ftrace_func_probe *probe = NULL, *iter;
4948	struct ftrace_ops_hash old_hash_ops;
4949	struct ftrace_func_entry *entry;
4950	struct ftrace_glob func_g;
4951	struct ftrace_hash **orig_hash;
4952	struct ftrace_hash *old_hash;
4953	struct ftrace_hash *hash = NULL;
4954	struct hlist_node *tmp;
4955	struct hlist_head hhd;
4956	char str[KSYM_SYMBOL_LEN];
4957	int count = 0;
4958	int i, ret = -ENODEV;
4959	int size;
4960
4961	if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4962		func_g.search = NULL;
4963	else {
4964		int not;
4965
4966		func_g.type = filter_parse_regex(glob, strlen(glob),
4967						 &func_g.search, &not);
4968		func_g.len = strlen(func_g.search);
4969
4970		/* we do not support '!' for function probes */
4971		if (WARN_ON(not))
4972			return -EINVAL;
4973	}
4974
4975	mutex_lock(&ftrace_lock);
4976	/* Check if the probe_ops is already registered */
4977	list_for_each_entry(iter, &tr->func_probes, list) {
4978		if (iter->probe_ops == probe_ops) {
4979			probe = iter;
4980			break;
4981		}
4982	}
4983	if (!probe)
4984		goto err_unlock_ftrace;
4985
4986	ret = -EINVAL;
4987	if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4988		goto err_unlock_ftrace;
4989
4990	acquire_probe_locked(probe);
4991
4992	mutex_unlock(&ftrace_lock);
4993
4994	mutex_lock(&probe->ops.func_hash->regex_lock);
4995
4996	orig_hash = &probe->ops.func_hash->filter_hash;
4997	old_hash = *orig_hash;
4998
4999	if (ftrace_hash_empty(old_hash))
5000		goto out_unlock;
5001
5002	old_hash_ops.filter_hash = old_hash;
5003	/* Probes only have filters */
5004	old_hash_ops.notrace_hash = NULL;
5005
5006	ret = -ENOMEM;
5007	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
5008	if (!hash)
5009		goto out_unlock;
5010
5011	INIT_HLIST_HEAD(&hhd);
5012
5013	size = 1 << hash->size_bits;
5014	for (i = 0; i < size; i++) {
5015		hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
5016
5017			if (func_g.search) {
5018				kallsyms_lookup(entry->ip, NULL, NULL,
5019						NULL, str);
5020				if (!ftrace_match(str, &func_g))
5021					continue;
5022			}
5023			count++;
5024			remove_hash_entry(hash, entry);
5025			hlist_add_head(&entry->hlist, &hhd);
5026		}
5027	}
5028
5029	/* Nothing found? */
5030	if (!count) {
5031		ret = -EINVAL;
5032		goto out_unlock;
5033	}
5034
5035	mutex_lock(&ftrace_lock);
5036
5037	WARN_ON(probe->ref < count);
5038
5039	probe->ref -= count;
5040
5041	if (ftrace_hash_empty(hash))
5042		ftrace_shutdown(&probe->ops, 0);
5043
5044	ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
5045					      hash, 1);
5046
5047	/* still need to update the function call sites */
5048	if (ftrace_enabled && !ftrace_hash_empty(hash))
5049		ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
5050				       &old_hash_ops);
5051	synchronize_rcu();
5052
5053	hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
5054		hlist_del(&entry->hlist);
5055		if (probe_ops->free)
5056			probe_ops->free(probe_ops, tr, entry->ip, probe->data);
5057		kfree(entry);
5058	}
5059	mutex_unlock(&ftrace_lock);
5060
5061 out_unlock:
5062	mutex_unlock(&probe->ops.func_hash->regex_lock);
5063	free_ftrace_hash(hash);
5064
5065	release_probe(probe);
5066
5067	return ret;
5068
5069 err_unlock_ftrace:
5070	mutex_unlock(&ftrace_lock);
5071	return ret;
5072}
5073
5074void clear_ftrace_function_probes(struct trace_array *tr)
5075{
5076	struct ftrace_func_probe *probe, *n;
5077
5078	list_for_each_entry_safe(probe, n, &tr->func_probes, list)
5079		unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
5080}
5081
5082static LIST_HEAD(ftrace_commands);
5083static DEFINE_MUTEX(ftrace_cmd_mutex);
5084
5085/*
5086 * Currently we only register ftrace commands from __init, so mark this
5087 * __init too.
5088 */
5089__init int register_ftrace_command(struct ftrace_func_command *cmd)
5090{
5091	struct ftrace_func_command *p;
5092	int ret = 0;
5093
5094	mutex_lock(&ftrace_cmd_mutex);
5095	list_for_each_entry(p, &ftrace_commands, list) {
5096		if (strcmp(cmd->name, p->name) == 0) {
5097			ret = -EBUSY;
5098			goto out_unlock;
5099		}
5100	}
5101	list_add(&cmd->list, &ftrace_commands);
5102 out_unlock:
5103	mutex_unlock(&ftrace_cmd_mutex);
5104
5105	return ret;
5106}
5107
5108/*
5109 * Currently we only unregister ftrace commands from __init, so mark
5110 * this __init too.
5111 */
5112__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
5113{
5114	struct ftrace_func_command *p, *n;
5115	int ret = -ENODEV;
5116
5117	mutex_lock(&ftrace_cmd_mutex);
5118	list_for_each_entry_safe(p, n, &ftrace_commands, list) {
5119		if (strcmp(cmd->name, p->name) == 0) {
5120			ret = 0;
5121			list_del_init(&p->list);
5122			goto out_unlock;
5123		}
5124	}
5125 out_unlock:
5126	mutex_unlock(&ftrace_cmd_mutex);
5127
5128	return ret;
5129}
5130
5131static int ftrace_process_regex(struct ftrace_iterator *iter,
5132				char *buff, int len, int enable)
5133{
5134	struct ftrace_hash *hash = iter->hash;
5135	struct trace_array *tr = iter->ops->private;
5136	char *func, *command, *next = buff;
5137	struct ftrace_func_command *p;
5138	int ret = -EINVAL;
5139
5140	func = strsep(&next, ":");
5141
5142	if (!next) {
5143		ret = ftrace_match_records(hash, func, len);
5144		if (!ret)
5145			ret = -EINVAL;
5146		if (ret < 0)
5147			return ret;
5148		return 0;
5149	}
5150
5151	/* command found */
5152
5153	command = strsep(&next, ":");
5154
5155	mutex_lock(&ftrace_cmd_mutex);
5156	list_for_each_entry(p, &ftrace_commands, list) {
5157		if (strcmp(p->name, command) == 0) {
5158			ret = p->func(tr, hash, func, command, next, enable);
5159			goto out_unlock;
5160		}
5161	}
5162 out_unlock:
5163	mutex_unlock(&ftrace_cmd_mutex);
5164
5165	return ret;
5166}
5167
5168static ssize_t
5169ftrace_regex_write(struct file *file, const char __user *ubuf,
5170		   size_t cnt, loff_t *ppos, int enable)
5171{
5172	struct ftrace_iterator *iter;
5173	struct trace_parser *parser;
5174	ssize_t ret, read;
5175
5176	if (!cnt)
5177		return 0;
5178
5179	if (file->f_mode & FMODE_READ) {
5180		struct seq_file *m = file->private_data;
5181		iter = m->private;
5182	} else
5183		iter = file->private_data;
5184
5185	if (unlikely(ftrace_disabled))
5186		return -ENODEV;
5187
5188	/* iter->hash is a local copy, so we don't need regex_lock */
5189
5190	parser = &iter->parser;
5191	read = trace_get_user(parser, ubuf, cnt, ppos);
5192
5193	if (read >= 0 && trace_parser_loaded(parser) &&
5194	    !trace_parser_cont(parser)) {
5195		ret = ftrace_process_regex(iter, parser->buffer,
5196					   parser->idx, enable);
5197		trace_parser_clear(parser);
5198		if (ret < 0)
5199			goto out;
5200	}
5201
5202	ret = read;
5203 out:
5204	return ret;
5205}
5206
5207ssize_t
5208ftrace_filter_write(struct file *file, const char __user *ubuf,
5209		    size_t cnt, loff_t *ppos)
5210{
5211	return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
5212}
5213
5214ssize_t
5215ftrace_notrace_write(struct file *file, const char __user *ubuf,
5216		     size_t cnt, loff_t *ppos)
5217{
5218	return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
5219}
5220
5221static int
5222__ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
5223{
5224	struct ftrace_func_entry *entry;
5225
5226	ip = ftrace_location(ip);
5227	if (!ip)
5228		return -EINVAL;
5229
5230	if (remove) {
5231		entry = ftrace_lookup_ip(hash, ip);
5232		if (!entry)
5233			return -ENOENT;
5234		free_hash_entry(hash, entry);
5235		return 0;
5236	}
5237
5238	entry = add_hash_entry(hash, ip);
5239	return entry ? 0 :  -ENOMEM;
5240}
5241
5242static int
5243ftrace_match_addr(struct ftrace_hash *hash, unsigned long *ips,
5244		  unsigned int cnt, int remove)
5245{
5246	unsigned int i;
5247	int err;
5248
5249	for (i = 0; i < cnt; i++) {
5250		err = __ftrace_match_addr(hash, ips[i], remove);
5251		if (err) {
5252			/*
5253			 * This expects the @hash is a temporary hash and if this
5254			 * fails the caller must free the @hash.
5255			 */
5256			return err;
5257		}
5258	}
5259	return 0;
5260}
5261
5262static int
5263ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
5264		unsigned long *ips, unsigned int cnt,
5265		int remove, int reset, int enable)
5266{
5267	struct ftrace_hash **orig_hash;
5268	struct ftrace_hash *hash;
5269	int ret;
5270
5271	if (unlikely(ftrace_disabled))
5272		return -ENODEV;
5273
5274	mutex_lock(&ops->func_hash->regex_lock);
5275
5276	if (enable)
5277		orig_hash = &ops->func_hash->filter_hash;
5278	else
5279		orig_hash = &ops->func_hash->notrace_hash;
5280
5281	if (reset)
5282		hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5283	else
5284		hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
5285
5286	if (!hash) {
5287		ret = -ENOMEM;
5288		goto out_regex_unlock;
5289	}
5290
5291	if (buf && !ftrace_match_records(hash, buf, len)) {
5292		ret = -EINVAL;
5293		goto out_regex_unlock;
5294	}
5295	if (ips) {
5296		ret = ftrace_match_addr(hash, ips, cnt, remove);
5297		if (ret < 0)
5298			goto out_regex_unlock;
5299	}
5300
5301	mutex_lock(&ftrace_lock);
5302	ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
5303	mutex_unlock(&ftrace_lock);
5304
5305 out_regex_unlock:
5306	mutex_unlock(&ops->func_hash->regex_lock);
5307
5308	free_ftrace_hash(hash);
5309	return ret;
5310}
5311
5312static int
5313ftrace_set_addr(struct ftrace_ops *ops, unsigned long *ips, unsigned int cnt,
5314		int remove, int reset, int enable)
5315{
5316	return ftrace_set_hash(ops, NULL, 0, ips, cnt, remove, reset, enable);
5317}
5318
5319#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5320
5321struct ftrace_direct_func {
5322	struct list_head	next;
5323	unsigned long		addr;
5324	int			count;
5325};
5326
5327static LIST_HEAD(ftrace_direct_funcs);
5328
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5329static int register_ftrace_function_nolock(struct ftrace_ops *ops);
5330
5331/*
5332 * If there are multiple ftrace_ops, use SAVE_REGS by default, so that direct
5333 * call will be jumped from ftrace_regs_caller. Only if the architecture does
5334 * not support ftrace_regs_caller but direct_call, use SAVE_ARGS so that it
5335 * jumps from ftrace_caller for multiple ftrace_ops.
 
 
 
 
 
 
 
 
 
 
 
5336 */
5337#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS
5338#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_ARGS)
5339#else
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5340#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS)
5341#endif
5342
5343static int check_direct_multi(struct ftrace_ops *ops)
5344{
5345	if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5346		return -EINVAL;
5347	if ((ops->flags & MULTI_FLAGS) != MULTI_FLAGS)
5348		return -EINVAL;
5349	return 0;
5350}
5351
5352static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long addr)
5353{
5354	struct ftrace_func_entry *entry, *del;
5355	int size, i;
5356
5357	size = 1 << hash->size_bits;
5358	for (i = 0; i < size; i++) {
5359		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5360			del = __ftrace_lookup_ip(direct_functions, entry->ip);
5361			if (del && del->direct == addr) {
5362				remove_hash_entry(direct_functions, del);
5363				kfree(del);
5364			}
5365		}
5366	}
5367}
5368
5369/**
5370 * register_ftrace_direct - Call a custom trampoline directly
5371 * for multiple functions registered in @ops
5372 * @ops: The address of the struct ftrace_ops object
5373 * @addr: The address of the trampoline to call at @ops functions
5374 *
5375 * This is used to connect a direct calls to @addr from the nop locations
5376 * of the functions registered in @ops (with by ftrace_set_filter_ip
5377 * function).
5378 *
5379 * The location that it calls (@addr) must be able to handle a direct call,
5380 * and save the parameters of the function being traced, and restore them
5381 * (or inject new ones if needed), before returning.
5382 *
5383 * Returns:
5384 *  0 on success
5385 *  -EINVAL  - The @ops object was already registered with this call or
5386 *             when there are no functions in @ops object.
5387 *  -EBUSY   - Another direct function is already attached (there can be only one)
5388 *  -ENODEV  - @ip does not point to a ftrace nop location (or not supported)
5389 *  -ENOMEM  - There was an allocation failure.
5390 */
5391int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5392{
5393	struct ftrace_hash *hash, *new_hash = NULL, *free_hash = NULL;
5394	struct ftrace_func_entry *entry, *new;
5395	int err = -EBUSY, size, i;
5396
5397	if (ops->func || ops->trampoline)
5398		return -EINVAL;
5399	if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5400		return -EINVAL;
5401	if (ops->flags & FTRACE_OPS_FL_ENABLED)
5402		return -EINVAL;
5403
5404	hash = ops->func_hash->filter_hash;
5405	if (ftrace_hash_empty(hash))
5406		return -EINVAL;
5407
5408	mutex_lock(&direct_mutex);
5409
5410	/* Make sure requested entries are not already registered.. */
5411	size = 1 << hash->size_bits;
5412	for (i = 0; i < size; i++) {
5413		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5414			if (ftrace_find_rec_direct(entry->ip))
5415				goto out_unlock;
5416		}
5417	}
5418
 
5419	err = -ENOMEM;
5420
5421	/* Make a copy hash to place the new and the old entries in */
5422	size = hash->count + direct_functions->count;
5423	if (size > 32)
5424		size = 32;
5425	new_hash = alloc_ftrace_hash(fls(size));
5426	if (!new_hash)
5427		goto out_unlock;
5428
5429	/* Now copy over the existing direct entries */
5430	size = 1 << direct_functions->size_bits;
5431	for (i = 0; i < size; i++) {
5432		hlist_for_each_entry(entry, &direct_functions->buckets[i], hlist) {
5433			new = add_hash_entry(new_hash, entry->ip);
5434			if (!new)
5435				goto out_unlock;
5436			new->direct = entry->direct;
5437		}
5438	}
5439
5440	/* ... and add the new entries */
5441	size = 1 << hash->size_bits;
5442	for (i = 0; i < size; i++) {
5443		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5444			new = add_hash_entry(new_hash, entry->ip);
5445			if (!new)
5446				goto out_unlock;
5447			/* Update both the copy and the hash entry */
5448			new->direct = addr;
5449			entry->direct = addr;
5450		}
5451	}
5452
5453	free_hash = direct_functions;
5454	rcu_assign_pointer(direct_functions, new_hash);
5455	new_hash = NULL;
5456
5457	ops->func = call_direct_funcs;
5458	ops->flags = MULTI_FLAGS;
5459	ops->trampoline = FTRACE_REGS_ADDR;
5460	ops->direct_call = addr;
5461
5462	err = register_ftrace_function_nolock(ops);
5463
 
 
 
 
5464 out_unlock:
5465	mutex_unlock(&direct_mutex);
5466
5467	if (free_hash && free_hash != EMPTY_HASH) {
5468		synchronize_rcu_tasks();
5469		free_ftrace_hash(free_hash);
5470	}
5471
5472	if (new_hash)
5473		free_ftrace_hash(new_hash);
5474
5475	return err;
5476}
5477EXPORT_SYMBOL_GPL(register_ftrace_direct);
5478
5479/**
5480 * unregister_ftrace_direct - Remove calls to custom trampoline
5481 * previously registered by register_ftrace_direct for @ops object.
5482 * @ops: The address of the struct ftrace_ops object
5483 *
5484 * This is used to remove a direct calls to @addr from the nop locations
5485 * of the functions registered in @ops (with by ftrace_set_filter_ip
5486 * function).
5487 *
5488 * Returns:
5489 *  0 on success
5490 *  -EINVAL - The @ops object was not properly registered.
5491 */
5492int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
5493			     bool free_filters)
5494{
5495	struct ftrace_hash *hash = ops->func_hash->filter_hash;
5496	int err;
5497
5498	if (check_direct_multi(ops))
5499		return -EINVAL;
5500	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5501		return -EINVAL;
5502
5503	mutex_lock(&direct_mutex);
5504	err = unregister_ftrace_function(ops);
5505	remove_direct_functions_hash(hash, addr);
5506	mutex_unlock(&direct_mutex);
5507
5508	/* cleanup for possible another register call */
5509	ops->func = NULL;
5510	ops->trampoline = 0;
5511
5512	if (free_filters)
5513		ftrace_free_filter(ops);
5514	return err;
5515}
5516EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5517
5518static int
5519__modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5520{
5521	struct ftrace_hash *hash;
5522	struct ftrace_func_entry *entry, *iter;
5523	static struct ftrace_ops tmp_ops = {
5524		.func		= ftrace_stub,
5525		.flags		= FTRACE_OPS_FL_STUB,
5526	};
5527	int i, size;
5528	int err;
5529
5530	lockdep_assert_held_once(&direct_mutex);
5531
5532	/* Enable the tmp_ops to have the same functions as the direct ops */
5533	ftrace_ops_init(&tmp_ops);
5534	tmp_ops.func_hash = ops->func_hash;
5535	tmp_ops.direct_call = addr;
5536
5537	err = register_ftrace_function_nolock(&tmp_ops);
5538	if (err)
5539		return err;
5540
5541	/*
5542	 * Now the ftrace_ops_list_func() is called to do the direct callers.
5543	 * We can safely change the direct functions attached to each entry.
5544	 */
5545	mutex_lock(&ftrace_lock);
5546
5547	hash = ops->func_hash->filter_hash;
5548	size = 1 << hash->size_bits;
5549	for (i = 0; i < size; i++) {
5550		hlist_for_each_entry(iter, &hash->buckets[i], hlist) {
5551			entry = __ftrace_lookup_ip(direct_functions, iter->ip);
5552			if (!entry)
5553				continue;
5554			entry->direct = addr;
5555		}
5556	}
5557	/* Prevent store tearing if a trampoline concurrently accesses the value */
5558	WRITE_ONCE(ops->direct_call, addr);
5559
5560	mutex_unlock(&ftrace_lock);
5561
5562	/* Removing the tmp_ops will add the updated direct callers to the functions */
5563	unregister_ftrace_function(&tmp_ops);
5564
5565	return err;
5566}
5567
5568/**
5569 * modify_ftrace_direct_nolock - Modify an existing direct 'multi' call
5570 * to call something else
5571 * @ops: The address of the struct ftrace_ops object
5572 * @addr: The address of the new trampoline to call at @ops functions
5573 *
5574 * This is used to unregister currently registered direct caller and
5575 * register new one @addr on functions registered in @ops object.
5576 *
5577 * Note there's window between ftrace_shutdown and ftrace_startup calls
5578 * where there will be no callbacks called.
5579 *
5580 * Caller should already have direct_mutex locked, so we don't lock
5581 * direct_mutex here.
5582 *
5583 * Returns: zero on success. Non zero on error, which includes:
5584 *  -EINVAL - The @ops object was not properly registered.
5585 */
5586int modify_ftrace_direct_nolock(struct ftrace_ops *ops, unsigned long addr)
5587{
5588	if (check_direct_multi(ops))
5589		return -EINVAL;
5590	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5591		return -EINVAL;
5592
5593	return __modify_ftrace_direct(ops, addr);
5594}
5595EXPORT_SYMBOL_GPL(modify_ftrace_direct_nolock);
5596
5597/**
5598 * modify_ftrace_direct - Modify an existing direct 'multi' call
5599 * to call something else
5600 * @ops: The address of the struct ftrace_ops object
5601 * @addr: The address of the new trampoline to call at @ops functions
5602 *
5603 * This is used to unregister currently registered direct caller and
5604 * register new one @addr on functions registered in @ops object.
5605 *
5606 * Note there's window between ftrace_shutdown and ftrace_startup calls
5607 * where there will be no callbacks called.
5608 *
5609 * Returns: zero on success. Non zero on error, which includes:
5610 *  -EINVAL - The @ops object was not properly registered.
5611 */
5612int modify_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
5613{
5614	int err;
5615
5616	if (check_direct_multi(ops))
5617		return -EINVAL;
5618	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5619		return -EINVAL;
5620
5621	mutex_lock(&direct_mutex);
5622	err = __modify_ftrace_direct(ops, addr);
5623	mutex_unlock(&direct_mutex);
5624	return err;
5625}
5626EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5627#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5628
5629/**
5630 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5631 * @ops: the ops to set the filter with
5632 * @ip: the address to add to or remove from the filter.
5633 * @remove: non zero to remove the ip from the filter
5634 * @reset: non zero to reset all filters before applying this filter.
5635 *
5636 * Filters denote which functions should be enabled when tracing is enabled
5637 * If @ip is NULL, it fails to update filter.
5638 *
5639 * This can allocate memory which must be freed before @ops can be freed,
5640 * either by removing each filtered addr or by using
5641 * ftrace_free_filter(@ops).
5642 */
5643int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5644			 int remove, int reset)
5645{
5646	ftrace_ops_init(ops);
5647	return ftrace_set_addr(ops, &ip, 1, remove, reset, 1);
5648}
5649EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5650
5651/**
5652 * ftrace_set_filter_ips - set functions to filter on in ftrace by addresses
5653 * @ops: the ops to set the filter with
5654 * @ips: the array of addresses to add to or remove from the filter.
5655 * @cnt: the number of addresses in @ips
5656 * @remove: non zero to remove ips from the filter
5657 * @reset: non zero to reset all filters before applying this filter.
5658 *
5659 * Filters denote which functions should be enabled when tracing is enabled
5660 * If @ips array or any ip specified within is NULL , it fails to update filter.
5661 *
5662 * This can allocate memory which must be freed before @ops can be freed,
5663 * either by removing each filtered addr or by using
5664 * ftrace_free_filter(@ops).
5665*/
5666int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
5667			  unsigned int cnt, int remove, int reset)
5668{
5669	ftrace_ops_init(ops);
5670	return ftrace_set_addr(ops, ips, cnt, remove, reset, 1);
5671}
5672EXPORT_SYMBOL_GPL(ftrace_set_filter_ips);
5673
5674/**
5675 * ftrace_ops_set_global_filter - setup ops to use global filters
5676 * @ops: the ops which will use the global filters
5677 *
5678 * ftrace users who need global function trace filtering should call this.
5679 * It can set the global filter only if ops were not initialized before.
5680 */
5681void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5682{
5683	if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5684		return;
5685
5686	ftrace_ops_init(ops);
5687	ops->func_hash = &global_ops.local_hash;
5688}
5689EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5690
5691static int
5692ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5693		 int reset, int enable)
5694{
5695	return ftrace_set_hash(ops, buf, len, NULL, 0, 0, reset, enable);
5696}
5697
5698/**
5699 * ftrace_set_filter - set a function to filter on in ftrace
5700 * @ops: the ops to set the filter with
5701 * @buf: the string that holds the function filter text.
5702 * @len: the length of the string.
5703 * @reset: non-zero to reset all filters before applying this filter.
5704 *
5705 * Filters denote which functions should be enabled when tracing is enabled.
5706 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5707 *
5708 * This can allocate memory which must be freed before @ops can be freed,
5709 * either by removing each filtered addr or by using
5710 * ftrace_free_filter(@ops).
5711 */
5712int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5713		       int len, int reset)
5714{
5715	ftrace_ops_init(ops);
5716	return ftrace_set_regex(ops, buf, len, reset, 1);
5717}
5718EXPORT_SYMBOL_GPL(ftrace_set_filter);
5719
5720/**
5721 * ftrace_set_notrace - set a function to not trace in ftrace
5722 * @ops: the ops to set the notrace filter with
5723 * @buf: the string that holds the function notrace text.
5724 * @len: the length of the string.
5725 * @reset: non-zero to reset all filters before applying this filter.
5726 *
5727 * Notrace Filters denote which functions should not be enabled when tracing
5728 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5729 * for tracing.
5730 *
5731 * This can allocate memory which must be freed before @ops can be freed,
5732 * either by removing each filtered addr or by using
5733 * ftrace_free_filter(@ops).
5734 */
5735int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5736			int len, int reset)
5737{
5738	ftrace_ops_init(ops);
5739	return ftrace_set_regex(ops, buf, len, reset, 0);
5740}
5741EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5742/**
5743 * ftrace_set_global_filter - set a function to filter on with global tracers
5744 * @buf: the string that holds the function filter text.
5745 * @len: the length of the string.
5746 * @reset: non-zero to reset all filters before applying this filter.
5747 *
5748 * Filters denote which functions should be enabled when tracing is enabled.
5749 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5750 */
5751void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5752{
5753	ftrace_set_regex(&global_ops, buf, len, reset, 1);
5754}
5755EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5756
5757/**
5758 * ftrace_set_global_notrace - set a function to not trace with global tracers
5759 * @buf: the string that holds the function notrace text.
5760 * @len: the length of the string.
5761 * @reset: non-zero to reset all filters before applying this filter.
5762 *
5763 * Notrace Filters denote which functions should not be enabled when tracing
5764 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5765 * for tracing.
5766 */
5767void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5768{
5769	ftrace_set_regex(&global_ops, buf, len, reset, 0);
5770}
5771EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5772
5773/*
5774 * command line interface to allow users to set filters on boot up.
5775 */
5776#define FTRACE_FILTER_SIZE		COMMAND_LINE_SIZE
5777static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5778static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5779
5780/* Used by function selftest to not test if filter is set */
5781bool ftrace_filter_param __initdata;
5782
5783static int __init set_ftrace_notrace(char *str)
5784{
5785	ftrace_filter_param = true;
5786	strscpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5787	return 1;
5788}
5789__setup("ftrace_notrace=", set_ftrace_notrace);
5790
5791static int __init set_ftrace_filter(char *str)
5792{
5793	ftrace_filter_param = true;
5794	strscpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
5795	return 1;
5796}
5797__setup("ftrace_filter=", set_ftrace_filter);
5798
5799#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5800static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
5801static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5802static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
5803
5804static int __init set_graph_function(char *str)
5805{
5806	strscpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
5807	return 1;
5808}
5809__setup("ftrace_graph_filter=", set_graph_function);
5810
5811static int __init set_graph_notrace_function(char *str)
5812{
5813	strscpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
5814	return 1;
5815}
5816__setup("ftrace_graph_notrace=", set_graph_notrace_function);
5817
5818static int __init set_graph_max_depth_function(char *str)
5819{
5820	if (!str)
5821		return 0;
5822	fgraph_max_depth = simple_strtoul(str, NULL, 0);
5823	return 1;
5824}
5825__setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
5826
5827static void __init set_ftrace_early_graph(char *buf, int enable)
5828{
5829	int ret;
5830	char *func;
5831	struct ftrace_hash *hash;
5832
5833	hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5834	if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
5835		return;
5836
5837	while (buf) {
5838		func = strsep(&buf, ",");
5839		/* we allow only one expression at a time */
5840		ret = ftrace_graph_set_hash(hash, func);
5841		if (ret)
5842			printk(KERN_DEBUG "ftrace: function %s not "
5843					  "traceable\n", func);
5844	}
5845
5846	if (enable)
5847		ftrace_graph_hash = hash;
5848	else
5849		ftrace_graph_notrace_hash = hash;
5850}
5851#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5852
5853void __init
5854ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
5855{
5856	char *func;
5857
5858	ftrace_ops_init(ops);
5859
5860	while (buf) {
5861		func = strsep(&buf, ",");
5862		ftrace_set_regex(ops, func, strlen(func), 0, enable);
5863	}
5864}
5865
5866static void __init set_ftrace_early_filters(void)
5867{
5868	if (ftrace_filter_buf[0])
5869		ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
5870	if (ftrace_notrace_buf[0])
5871		ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
5872#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5873	if (ftrace_graph_buf[0])
5874		set_ftrace_early_graph(ftrace_graph_buf, 1);
5875	if (ftrace_graph_notrace_buf[0])
5876		set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
5877#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
5878}
5879
5880int ftrace_regex_release(struct inode *inode, struct file *file)
5881{
5882	struct seq_file *m = (struct seq_file *)file->private_data;
5883	struct ftrace_iterator *iter;
5884	struct ftrace_hash **orig_hash;
5885	struct trace_parser *parser;
5886	int filter_hash;
5887
5888	if (file->f_mode & FMODE_READ) {
5889		iter = m->private;
5890		seq_release(inode, file);
5891	} else
5892		iter = file->private_data;
5893
5894	parser = &iter->parser;
5895	if (trace_parser_loaded(parser)) {
5896		int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
5897
5898		ftrace_process_regex(iter, parser->buffer,
5899				     parser->idx, enable);
5900	}
5901
5902	trace_parser_put(parser);
5903
5904	mutex_lock(&iter->ops->func_hash->regex_lock);
5905
5906	if (file->f_mode & FMODE_WRITE) {
5907		filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
5908
5909		if (filter_hash) {
5910			orig_hash = &iter->ops->func_hash->filter_hash;
5911			if (iter->tr) {
5912				if (list_empty(&iter->tr->mod_trace))
5913					iter->hash->flags &= ~FTRACE_HASH_FL_MOD;
5914				else
5915					iter->hash->flags |= FTRACE_HASH_FL_MOD;
5916			}
5917		} else
5918			orig_hash = &iter->ops->func_hash->notrace_hash;
5919
5920		mutex_lock(&ftrace_lock);
5921		ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
5922						      iter->hash, filter_hash);
5923		mutex_unlock(&ftrace_lock);
5924	} else {
5925		/* For read only, the hash is the ops hash */
5926		iter->hash = NULL;
5927	}
5928
5929	mutex_unlock(&iter->ops->func_hash->regex_lock);
5930	free_ftrace_hash(iter->hash);
5931	if (iter->tr)
5932		trace_array_put(iter->tr);
5933	kfree(iter);
5934
5935	return 0;
5936}
5937
5938static const struct file_operations ftrace_avail_fops = {
5939	.open = ftrace_avail_open,
5940	.read = seq_read,
5941	.llseek = seq_lseek,
5942	.release = seq_release_private,
5943};
5944
5945static const struct file_operations ftrace_enabled_fops = {
5946	.open = ftrace_enabled_open,
5947	.read = seq_read,
5948	.llseek = seq_lseek,
5949	.release = seq_release_private,
5950};
5951
5952static const struct file_operations ftrace_touched_fops = {
5953	.open = ftrace_touched_open,
5954	.read = seq_read,
5955	.llseek = seq_lseek,
5956	.release = seq_release_private,
5957};
5958
5959static const struct file_operations ftrace_avail_addrs_fops = {
5960	.open = ftrace_avail_addrs_open,
5961	.read = seq_read,
5962	.llseek = seq_lseek,
5963	.release = seq_release_private,
5964};
5965
5966static const struct file_operations ftrace_filter_fops = {
5967	.open = ftrace_filter_open,
5968	.read = seq_read,
5969	.write = ftrace_filter_write,
5970	.llseek = tracing_lseek,
5971	.release = ftrace_regex_release,
5972};
5973
5974static const struct file_operations ftrace_notrace_fops = {
5975	.open = ftrace_notrace_open,
5976	.read = seq_read,
5977	.write = ftrace_notrace_write,
5978	.llseek = tracing_lseek,
5979	.release = ftrace_regex_release,
5980};
5981
5982#ifdef CONFIG_FUNCTION_GRAPH_TRACER
5983
5984static DEFINE_MUTEX(graph_lock);
5985
5986struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
5987struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
5988
5989enum graph_filter_type {
5990	GRAPH_FILTER_NOTRACE	= 0,
5991	GRAPH_FILTER_FUNCTION,
5992};
5993
5994#define FTRACE_GRAPH_EMPTY	((void *)1)
5995
5996struct ftrace_graph_data {
5997	struct ftrace_hash		*hash;
5998	struct ftrace_func_entry	*entry;
5999	int				idx;   /* for hash table iteration */
6000	enum graph_filter_type		type;
6001	struct ftrace_hash		*new_hash;
6002	const struct seq_operations	*seq_ops;
6003	struct trace_parser		parser;
6004};
6005
6006static void *
6007__g_next(struct seq_file *m, loff_t *pos)
6008{
6009	struct ftrace_graph_data *fgd = m->private;
6010	struct ftrace_func_entry *entry = fgd->entry;
6011	struct hlist_head *head;
6012	int i, idx = fgd->idx;
6013
6014	if (*pos >= fgd->hash->count)
6015		return NULL;
6016
6017	if (entry) {
6018		hlist_for_each_entry_continue(entry, hlist) {
6019			fgd->entry = entry;
6020			return entry;
6021		}
6022
6023		idx++;
6024	}
6025
6026	for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
6027		head = &fgd->hash->buckets[i];
6028		hlist_for_each_entry(entry, head, hlist) {
6029			fgd->entry = entry;
6030			fgd->idx = i;
6031			return entry;
6032		}
6033	}
6034	return NULL;
6035}
6036
6037static void *
6038g_next(struct seq_file *m, void *v, loff_t *pos)
6039{
6040	(*pos)++;
6041	return __g_next(m, pos);
6042}
6043
6044static void *g_start(struct seq_file *m, loff_t *pos)
6045{
6046	struct ftrace_graph_data *fgd = m->private;
6047
6048	mutex_lock(&graph_lock);
6049
6050	if (fgd->type == GRAPH_FILTER_FUNCTION)
6051		fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6052					lockdep_is_held(&graph_lock));
6053	else
6054		fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6055					lockdep_is_held(&graph_lock));
6056
6057	/* Nothing, tell g_show to print all functions are enabled */
6058	if (ftrace_hash_empty(fgd->hash) && !*pos)
6059		return FTRACE_GRAPH_EMPTY;
6060
6061	fgd->idx = 0;
6062	fgd->entry = NULL;
6063	return __g_next(m, pos);
6064}
6065
6066static void g_stop(struct seq_file *m, void *p)
6067{
6068	mutex_unlock(&graph_lock);
6069}
6070
6071static int g_show(struct seq_file *m, void *v)
6072{
6073	struct ftrace_func_entry *entry = v;
6074
6075	if (!entry)
6076		return 0;
6077
6078	if (entry == FTRACE_GRAPH_EMPTY) {
6079		struct ftrace_graph_data *fgd = m->private;
6080
6081		if (fgd->type == GRAPH_FILTER_FUNCTION)
6082			seq_puts(m, "#### all functions enabled ####\n");
6083		else
6084			seq_puts(m, "#### no functions disabled ####\n");
6085		return 0;
6086	}
6087
6088	seq_printf(m, "%ps\n", (void *)entry->ip);
6089
6090	return 0;
6091}
6092
6093static const struct seq_operations ftrace_graph_seq_ops = {
6094	.start = g_start,
6095	.next = g_next,
6096	.stop = g_stop,
6097	.show = g_show,
6098};
6099
6100static int
6101__ftrace_graph_open(struct inode *inode, struct file *file,
6102		    struct ftrace_graph_data *fgd)
6103{
6104	int ret;
6105	struct ftrace_hash *new_hash = NULL;
6106
6107	ret = security_locked_down(LOCKDOWN_TRACEFS);
6108	if (ret)
6109		return ret;
6110
6111	if (file->f_mode & FMODE_WRITE) {
6112		const int size_bits = FTRACE_HASH_DEFAULT_BITS;
6113
6114		if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
6115			return -ENOMEM;
6116
6117		if (file->f_flags & O_TRUNC)
6118			new_hash = alloc_ftrace_hash(size_bits);
6119		else
6120			new_hash = alloc_and_copy_ftrace_hash(size_bits,
6121							      fgd->hash);
6122		if (!new_hash) {
6123			ret = -ENOMEM;
6124			goto out;
6125		}
6126	}
6127
6128	if (file->f_mode & FMODE_READ) {
6129		ret = seq_open(file, &ftrace_graph_seq_ops);
6130		if (!ret) {
6131			struct seq_file *m = file->private_data;
6132			m->private = fgd;
6133		} else {
6134			/* Failed */
6135			free_ftrace_hash(new_hash);
6136			new_hash = NULL;
6137		}
6138	} else
6139		file->private_data = fgd;
6140
6141out:
6142	if (ret < 0 && file->f_mode & FMODE_WRITE)
6143		trace_parser_put(&fgd->parser);
6144
6145	fgd->new_hash = new_hash;
6146
6147	/*
6148	 * All uses of fgd->hash must be taken with the graph_lock
6149	 * held. The graph_lock is going to be released, so force
6150	 * fgd->hash to be reinitialized when it is taken again.
6151	 */
6152	fgd->hash = NULL;
6153
6154	return ret;
6155}
6156
6157static int
6158ftrace_graph_open(struct inode *inode, struct file *file)
6159{
6160	struct ftrace_graph_data *fgd;
6161	int ret;
6162
6163	if (unlikely(ftrace_disabled))
6164		return -ENODEV;
6165
6166	fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6167	if (fgd == NULL)
6168		return -ENOMEM;
6169
6170	mutex_lock(&graph_lock);
6171
6172	fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6173					lockdep_is_held(&graph_lock));
6174	fgd->type = GRAPH_FILTER_FUNCTION;
6175	fgd->seq_ops = &ftrace_graph_seq_ops;
6176
6177	ret = __ftrace_graph_open(inode, file, fgd);
6178	if (ret < 0)
6179		kfree(fgd);
6180
6181	mutex_unlock(&graph_lock);
6182	return ret;
6183}
6184
6185static int
6186ftrace_graph_notrace_open(struct inode *inode, struct file *file)
6187{
6188	struct ftrace_graph_data *fgd;
6189	int ret;
6190
6191	if (unlikely(ftrace_disabled))
6192		return -ENODEV;
6193
6194	fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6195	if (fgd == NULL)
6196		return -ENOMEM;
6197
6198	mutex_lock(&graph_lock);
6199
6200	fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6201					lockdep_is_held(&graph_lock));
6202	fgd->type = GRAPH_FILTER_NOTRACE;
6203	fgd->seq_ops = &ftrace_graph_seq_ops;
6204
6205	ret = __ftrace_graph_open(inode, file, fgd);
6206	if (ret < 0)
6207		kfree(fgd);
6208
6209	mutex_unlock(&graph_lock);
6210	return ret;
6211}
6212
6213static int
6214ftrace_graph_release(struct inode *inode, struct file *file)
6215{
6216	struct ftrace_graph_data *fgd;
6217	struct ftrace_hash *old_hash, *new_hash;
6218	struct trace_parser *parser;
6219	int ret = 0;
6220
6221	if (file->f_mode & FMODE_READ) {
6222		struct seq_file *m = file->private_data;
6223
6224		fgd = m->private;
6225		seq_release(inode, file);
6226	} else {
6227		fgd = file->private_data;
6228	}
6229
6230
6231	if (file->f_mode & FMODE_WRITE) {
6232
6233		parser = &fgd->parser;
6234
6235		if (trace_parser_loaded((parser))) {
6236			ret = ftrace_graph_set_hash(fgd->new_hash,
6237						    parser->buffer);
6238		}
6239
6240		trace_parser_put(parser);
6241
6242		new_hash = __ftrace_hash_move(fgd->new_hash);
6243		if (!new_hash) {
6244			ret = -ENOMEM;
6245			goto out;
6246		}
6247
6248		mutex_lock(&graph_lock);
6249
6250		if (fgd->type == GRAPH_FILTER_FUNCTION) {
6251			old_hash = rcu_dereference_protected(ftrace_graph_hash,
6252					lockdep_is_held(&graph_lock));
6253			rcu_assign_pointer(ftrace_graph_hash, new_hash);
6254		} else {
6255			old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6256					lockdep_is_held(&graph_lock));
6257			rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
6258		}
6259
6260		mutex_unlock(&graph_lock);
6261
6262		/*
6263		 * We need to do a hard force of sched synchronization.
6264		 * This is because we use preempt_disable() to do RCU, but
6265		 * the function tracers can be called where RCU is not watching
6266		 * (like before user_exit()). We can not rely on the RCU
6267		 * infrastructure to do the synchronization, thus we must do it
6268		 * ourselves.
6269		 */
6270		if (old_hash != EMPTY_HASH)
6271			synchronize_rcu_tasks_rude();
6272
6273		free_ftrace_hash(old_hash);
6274	}
6275
6276 out:
6277	free_ftrace_hash(fgd->new_hash);
6278	kfree(fgd);
6279
6280	return ret;
6281}
6282
6283static int
6284ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
6285{
6286	struct ftrace_glob func_g;
6287	struct dyn_ftrace *rec;
6288	struct ftrace_page *pg;
6289	struct ftrace_func_entry *entry;
6290	int fail = 1;
6291	int not;
6292
6293	/* decode regex */
6294	func_g.type = filter_parse_regex(buffer, strlen(buffer),
6295					 &func_g.search, &not);
6296
6297	func_g.len = strlen(func_g.search);
6298
6299	mutex_lock(&ftrace_lock);
6300
6301	if (unlikely(ftrace_disabled)) {
6302		mutex_unlock(&ftrace_lock);
6303		return -ENODEV;
6304	}
6305
6306	do_for_each_ftrace_rec(pg, rec) {
6307
6308		if (rec->flags & FTRACE_FL_DISABLED)
6309			continue;
6310
6311		if (ftrace_match_record(rec, &func_g, NULL, 0)) {
6312			entry = ftrace_lookup_ip(hash, rec->ip);
6313
6314			if (!not) {
6315				fail = 0;
6316
6317				if (entry)
6318					continue;
6319				if (add_hash_entry(hash, rec->ip) == NULL)
6320					goto out;
6321			} else {
6322				if (entry) {
6323					free_hash_entry(hash, entry);
6324					fail = 0;
6325				}
6326			}
6327		}
6328	} while_for_each_ftrace_rec();
6329out:
6330	mutex_unlock(&ftrace_lock);
6331
6332	if (fail)
6333		return -EINVAL;
6334
6335	return 0;
6336}
6337
6338static ssize_t
6339ftrace_graph_write(struct file *file, const char __user *ubuf,
6340		   size_t cnt, loff_t *ppos)
6341{
6342	ssize_t read, ret = 0;
6343	struct ftrace_graph_data *fgd = file->private_data;
6344	struct trace_parser *parser;
6345
6346	if (!cnt)
6347		return 0;
6348
6349	/* Read mode uses seq functions */
6350	if (file->f_mode & FMODE_READ) {
6351		struct seq_file *m = file->private_data;
6352		fgd = m->private;
6353	}
6354
6355	parser = &fgd->parser;
6356
6357	read = trace_get_user(parser, ubuf, cnt, ppos);
6358
6359	if (read >= 0 && trace_parser_loaded(parser) &&
6360	    !trace_parser_cont(parser)) {
6361
6362		ret = ftrace_graph_set_hash(fgd->new_hash,
6363					    parser->buffer);
6364		trace_parser_clear(parser);
6365	}
6366
6367	if (!ret)
6368		ret = read;
6369
6370	return ret;
6371}
6372
6373static const struct file_operations ftrace_graph_fops = {
6374	.open		= ftrace_graph_open,
6375	.read		= seq_read,
6376	.write		= ftrace_graph_write,
6377	.llseek		= tracing_lseek,
6378	.release	= ftrace_graph_release,
6379};
6380
6381static const struct file_operations ftrace_graph_notrace_fops = {
6382	.open		= ftrace_graph_notrace_open,
6383	.read		= seq_read,
6384	.write		= ftrace_graph_write,
6385	.llseek		= tracing_lseek,
6386	.release	= ftrace_graph_release,
6387};
6388#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6389
6390void ftrace_create_filter_files(struct ftrace_ops *ops,
6391				struct dentry *parent)
6392{
6393
6394	trace_create_file("set_ftrace_filter", TRACE_MODE_WRITE, parent,
6395			  ops, &ftrace_filter_fops);
6396
6397	trace_create_file("set_ftrace_notrace", TRACE_MODE_WRITE, parent,
6398			  ops, &ftrace_notrace_fops);
6399}
6400
6401/*
6402 * The name "destroy_filter_files" is really a misnomer. Although
6403 * in the future, it may actually delete the files, but this is
6404 * really intended to make sure the ops passed in are disabled
6405 * and that when this function returns, the caller is free to
6406 * free the ops.
6407 *
6408 * The "destroy" name is only to match the "create" name that this
6409 * should be paired with.
6410 */
6411void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6412{
6413	mutex_lock(&ftrace_lock);
6414	if (ops->flags & FTRACE_OPS_FL_ENABLED)
6415		ftrace_shutdown(ops, 0);
6416	ops->flags |= FTRACE_OPS_FL_DELETED;
6417	ftrace_free_filter(ops);
6418	mutex_unlock(&ftrace_lock);
6419}
6420
6421static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6422{
6423
6424	trace_create_file("available_filter_functions", TRACE_MODE_READ,
6425			d_tracer, NULL, &ftrace_avail_fops);
6426
6427	trace_create_file("available_filter_functions_addrs", TRACE_MODE_READ,
6428			d_tracer, NULL, &ftrace_avail_addrs_fops);
6429
6430	trace_create_file("enabled_functions", TRACE_MODE_READ,
6431			d_tracer, NULL, &ftrace_enabled_fops);
6432
6433	trace_create_file("touched_functions", TRACE_MODE_READ,
6434			d_tracer, NULL, &ftrace_touched_fops);
6435
6436	ftrace_create_filter_files(&global_ops, d_tracer);
6437
6438#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6439	trace_create_file("set_graph_function", TRACE_MODE_WRITE, d_tracer,
6440				    NULL,
6441				    &ftrace_graph_fops);
6442	trace_create_file("set_graph_notrace", TRACE_MODE_WRITE, d_tracer,
6443				    NULL,
6444				    &ftrace_graph_notrace_fops);
6445#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6446
6447	return 0;
6448}
6449
6450static int ftrace_cmp_ips(const void *a, const void *b)
6451{
6452	const unsigned long *ipa = a;
6453	const unsigned long *ipb = b;
6454
6455	if (*ipa > *ipb)
6456		return 1;
6457	if (*ipa < *ipb)
6458		return -1;
6459	return 0;
6460}
6461
6462#ifdef CONFIG_FTRACE_SORT_STARTUP_TEST
6463static void test_is_sorted(unsigned long *start, unsigned long count)
6464{
6465	int i;
6466
6467	for (i = 1; i < count; i++) {
6468		if (WARN(start[i - 1] > start[i],
6469			 "[%d] %pS at %lx is not sorted with %pS at %lx\n", i,
6470			 (void *)start[i - 1], start[i - 1],
6471			 (void *)start[i], start[i]))
6472			break;
6473	}
6474	if (i == count)
6475		pr_info("ftrace section at %px sorted properly\n", start);
6476}
6477#else
6478static void test_is_sorted(unsigned long *start, unsigned long count)
6479{
6480}
6481#endif
6482
6483static int ftrace_process_locs(struct module *mod,
6484			       unsigned long *start,
6485			       unsigned long *end)
6486{
6487	struct ftrace_page *pg_unuse = NULL;
6488	struct ftrace_page *start_pg;
6489	struct ftrace_page *pg;
6490	struct dyn_ftrace *rec;
6491	unsigned long skipped = 0;
6492	unsigned long count;
6493	unsigned long *p;
6494	unsigned long addr;
6495	unsigned long flags = 0; /* Shut up gcc */
6496	int ret = -ENOMEM;
6497
6498	count = end - start;
6499
6500	if (!count)
6501		return 0;
6502
6503	/*
6504	 * Sorting mcount in vmlinux at build time depend on
6505	 * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in
6506	 * modules can not be sorted at build time.
6507	 */
6508	if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
6509		sort(start, count, sizeof(*start),
6510		     ftrace_cmp_ips, NULL);
6511	} else {
6512		test_is_sorted(start, count);
6513	}
6514
6515	start_pg = ftrace_allocate_pages(count);
6516	if (!start_pg)
6517		return -ENOMEM;
6518
6519	mutex_lock(&ftrace_lock);
6520
6521	/*
6522	 * Core and each module needs their own pages, as
6523	 * modules will free them when they are removed.
6524	 * Force a new page to be allocated for modules.
6525	 */
6526	if (!mod) {
6527		WARN_ON(ftrace_pages || ftrace_pages_start);
6528		/* First initialization */
6529		ftrace_pages = ftrace_pages_start = start_pg;
6530	} else {
6531		if (!ftrace_pages)
6532			goto out;
6533
6534		if (WARN_ON(ftrace_pages->next)) {
6535			/* Hmm, we have free pages? */
6536			while (ftrace_pages->next)
6537				ftrace_pages = ftrace_pages->next;
6538		}
6539
6540		ftrace_pages->next = start_pg;
6541	}
6542
6543	p = start;
6544	pg = start_pg;
6545	while (p < end) {
6546		unsigned long end_offset;
6547		addr = ftrace_call_adjust(*p++);
6548		/*
6549		 * Some architecture linkers will pad between
6550		 * the different mcount_loc sections of different
6551		 * object files to satisfy alignments.
6552		 * Skip any NULL pointers.
6553		 */
6554		if (!addr) {
6555			skipped++;
6556			continue;
6557		}
6558
6559		end_offset = (pg->index+1) * sizeof(pg->records[0]);
6560		if (end_offset > PAGE_SIZE << pg->order) {
6561			/* We should have allocated enough */
6562			if (WARN_ON(!pg->next))
6563				break;
6564			pg = pg->next;
6565		}
6566
6567		rec = &pg->records[pg->index++];
6568		rec->ip = addr;
6569	}
6570
6571	if (pg->next) {
6572		pg_unuse = pg->next;
6573		pg->next = NULL;
6574	}
6575
6576	/* Assign the last page to ftrace_pages */
6577	ftrace_pages = pg;
6578
6579	/*
6580	 * We only need to disable interrupts on start up
6581	 * because we are modifying code that an interrupt
6582	 * may execute, and the modification is not atomic.
6583	 * But for modules, nothing runs the code we modify
6584	 * until we are finished with it, and there's no
6585	 * reason to cause large interrupt latencies while we do it.
6586	 */
6587	if (!mod)
6588		local_irq_save(flags);
6589	ftrace_update_code(mod, start_pg);
6590	if (!mod)
6591		local_irq_restore(flags);
6592	ret = 0;
6593 out:
6594	mutex_unlock(&ftrace_lock);
6595
6596	/* We should have used all pages unless we skipped some */
6597	if (pg_unuse) {
6598		WARN_ON(!skipped);
6599		/* Need to synchronize with ftrace_location_range() */
6600		synchronize_rcu();
6601		ftrace_free_pages(pg_unuse);
6602	}
6603	return ret;
6604}
6605
6606struct ftrace_mod_func {
6607	struct list_head	list;
6608	char			*name;
6609	unsigned long		ip;
6610	unsigned int		size;
6611};
6612
6613struct ftrace_mod_map {
6614	struct rcu_head		rcu;
6615	struct list_head	list;
6616	struct module		*mod;
6617	unsigned long		start_addr;
6618	unsigned long		end_addr;
6619	struct list_head	funcs;
6620	unsigned int		num_funcs;
6621};
6622
6623static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6624					 unsigned long *value, char *type,
6625					 char *name, char *module_name,
6626					 int *exported)
6627{
6628	struct ftrace_ops *op;
6629
6630	list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6631		if (!op->trampoline || symnum--)
6632			continue;
6633		*value = op->trampoline;
6634		*type = 't';
6635		strscpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6636		strscpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6637		*exported = 0;
6638		return 0;
6639	}
6640
6641	return -ERANGE;
6642}
6643
6644#if defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) || defined(CONFIG_MODULES)
6645/*
6646 * Check if the current ops references the given ip.
6647 *
6648 * If the ops traces all functions, then it was already accounted for.
6649 * If the ops does not trace the current record function, skip it.
6650 * If the ops ignores the function via notrace filter, skip it.
6651 */
6652static bool
6653ops_references_ip(struct ftrace_ops *ops, unsigned long ip)
6654{
6655	/* If ops isn't enabled, ignore it */
6656	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
6657		return false;
6658
6659	/* If ops traces all then it includes this function */
6660	if (ops_traces_mod(ops))
6661		return true;
6662
6663	/* The function must be in the filter */
6664	if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
6665	    !__ftrace_lookup_ip(ops->func_hash->filter_hash, ip))
6666		return false;
6667
6668	/* If in notrace hash, we ignore it too */
6669	if (ftrace_lookup_ip(ops->func_hash->notrace_hash, ip))
6670		return false;
6671
6672	return true;
6673}
6674#endif
6675
6676#ifdef CONFIG_MODULES
6677
6678#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6679
6680static LIST_HEAD(ftrace_mod_maps);
6681
6682static int referenced_filters(struct dyn_ftrace *rec)
6683{
6684	struct ftrace_ops *ops;
6685	int cnt = 0;
6686
6687	for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6688		if (ops_references_ip(ops, rec->ip)) {
6689			if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6690				continue;
6691			if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6692				continue;
6693			cnt++;
6694			if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6695				rec->flags |= FTRACE_FL_REGS;
6696			if (cnt == 1 && ops->trampoline)
6697				rec->flags |= FTRACE_FL_TRAMP;
6698			else
6699				rec->flags &= ~FTRACE_FL_TRAMP;
6700		}
6701	}
6702
6703	return cnt;
6704}
6705
6706static void
6707clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6708{
6709	struct ftrace_func_entry *entry;
6710	struct dyn_ftrace *rec;
6711	int i;
6712
6713	if (ftrace_hash_empty(hash))
6714		return;
6715
6716	for (i = 0; i < pg->index; i++) {
6717		rec = &pg->records[i];
6718		entry = __ftrace_lookup_ip(hash, rec->ip);
6719		/*
6720		 * Do not allow this rec to match again.
6721		 * Yeah, it may waste some memory, but will be removed
6722		 * if/when the hash is modified again.
6723		 */
6724		if (entry)
6725			entry->ip = 0;
6726	}
6727}
6728
6729/* Clear any records from hashes */
6730static void clear_mod_from_hashes(struct ftrace_page *pg)
6731{
6732	struct trace_array *tr;
6733
6734	mutex_lock(&trace_types_lock);
6735	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6736		if (!tr->ops || !tr->ops->func_hash)
6737			continue;
6738		mutex_lock(&tr->ops->func_hash->regex_lock);
6739		clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6740		clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6741		mutex_unlock(&tr->ops->func_hash->regex_lock);
6742	}
6743	mutex_unlock(&trace_types_lock);
6744}
6745
6746static void ftrace_free_mod_map(struct rcu_head *rcu)
6747{
6748	struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6749	struct ftrace_mod_func *mod_func;
6750	struct ftrace_mod_func *n;
6751
6752	/* All the contents of mod_map are now not visible to readers */
6753	list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6754		kfree(mod_func->name);
6755		list_del(&mod_func->list);
6756		kfree(mod_func);
6757	}
6758
6759	kfree(mod_map);
6760}
6761
6762void ftrace_release_mod(struct module *mod)
6763{
6764	struct ftrace_mod_map *mod_map;
6765	struct ftrace_mod_map *n;
6766	struct dyn_ftrace *rec;
6767	struct ftrace_page **last_pg;
6768	struct ftrace_page *tmp_page = NULL;
6769	struct ftrace_page *pg;
6770
6771	mutex_lock(&ftrace_lock);
6772
6773	if (ftrace_disabled)
6774		goto out_unlock;
6775
6776	list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6777		if (mod_map->mod == mod) {
6778			list_del_rcu(&mod_map->list);
6779			call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6780			break;
6781		}
6782	}
6783
6784	/*
6785	 * Each module has its own ftrace_pages, remove
6786	 * them from the list.
6787	 */
6788	last_pg = &ftrace_pages_start;
6789	for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6790		rec = &pg->records[0];
6791		if (within_module(rec->ip, mod)) {
 
6792			/*
6793			 * As core pages are first, the first
6794			 * page should never be a module page.
6795			 */
6796			if (WARN_ON(pg == ftrace_pages_start))
6797				goto out_unlock;
6798
6799			/* Check if we are deleting the last page */
6800			if (pg == ftrace_pages)
6801				ftrace_pages = next_to_ftrace_page(last_pg);
6802
6803			ftrace_update_tot_cnt -= pg->index;
6804			*last_pg = pg->next;
6805
6806			pg->next = tmp_page;
6807			tmp_page = pg;
6808		} else
6809			last_pg = &pg->next;
6810	}
6811 out_unlock:
6812	mutex_unlock(&ftrace_lock);
6813
6814	/* Need to synchronize with ftrace_location_range() */
6815	if (tmp_page)
6816		synchronize_rcu();
6817	for (pg = tmp_page; pg; pg = tmp_page) {
6818
6819		/* Needs to be called outside of ftrace_lock */
6820		clear_mod_from_hashes(pg);
6821
6822		if (pg->records) {
6823			free_pages((unsigned long)pg->records, pg->order);
6824			ftrace_number_of_pages -= 1 << pg->order;
6825		}
6826		tmp_page = pg->next;
6827		kfree(pg);
6828		ftrace_number_of_groups--;
6829	}
6830}
6831
6832void ftrace_module_enable(struct module *mod)
6833{
6834	struct dyn_ftrace *rec;
6835	struct ftrace_page *pg;
6836
6837	mutex_lock(&ftrace_lock);
6838
6839	if (ftrace_disabled)
6840		goto out_unlock;
6841
6842	/*
6843	 * If the tracing is enabled, go ahead and enable the record.
6844	 *
6845	 * The reason not to enable the record immediately is the
6846	 * inherent check of ftrace_make_nop/ftrace_make_call for
6847	 * correct previous instructions.  Making first the NOP
6848	 * conversion puts the module to the correct state, thus
6849	 * passing the ftrace_make_call check.
6850	 *
6851	 * We also delay this to after the module code already set the
6852	 * text to read-only, as we now need to set it back to read-write
6853	 * so that we can modify the text.
6854	 */
6855	if (ftrace_start_up)
6856		ftrace_arch_code_modify_prepare();
6857
6858	do_for_each_ftrace_rec(pg, rec) {
6859		int cnt;
6860		/*
6861		 * do_for_each_ftrace_rec() is a double loop.
6862		 * module text shares the pg. If a record is
6863		 * not part of this module, then skip this pg,
6864		 * which the "break" will do.
6865		 */
6866		if (!within_module(rec->ip, mod))
 
6867			break;
6868
6869		/* Weak functions should still be ignored */
6870		if (!test_for_valid_rec(rec)) {
6871			/* Clear all other flags. Should not be enabled anyway */
6872			rec->flags = FTRACE_FL_DISABLED;
6873			continue;
6874		}
6875
6876		cnt = 0;
6877
6878		/*
6879		 * When adding a module, we need to check if tracers are
6880		 * currently enabled and if they are, and can trace this record,
6881		 * we need to enable the module functions as well as update the
6882		 * reference counts for those function records.
6883		 */
6884		if (ftrace_start_up)
6885			cnt += referenced_filters(rec);
6886
6887		rec->flags &= ~FTRACE_FL_DISABLED;
6888		rec->flags += cnt;
6889
6890		if (ftrace_start_up && cnt) {
6891			int failed = __ftrace_replace_code(rec, 1);
6892			if (failed) {
6893				ftrace_bug(failed, rec);
6894				goto out_loop;
6895			}
6896		}
6897
6898	} while_for_each_ftrace_rec();
6899
6900 out_loop:
6901	if (ftrace_start_up)
6902		ftrace_arch_code_modify_post_process();
6903
6904 out_unlock:
6905	mutex_unlock(&ftrace_lock);
6906
6907	process_cached_mods(mod->name);
6908}
6909
6910void ftrace_module_init(struct module *mod)
6911{
6912	int ret;
6913
6914	if (ftrace_disabled || !mod->num_ftrace_callsites)
6915		return;
6916
6917	ret = ftrace_process_locs(mod, mod->ftrace_callsites,
6918				  mod->ftrace_callsites + mod->num_ftrace_callsites);
6919	if (ret)
6920		pr_warn("ftrace: failed to allocate entries for module '%s' functions\n",
6921			mod->name);
6922}
6923
6924static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
6925				struct dyn_ftrace *rec)
6926{
6927	struct ftrace_mod_func *mod_func;
6928	unsigned long symsize;
6929	unsigned long offset;
6930	char str[KSYM_SYMBOL_LEN];
6931	char *modname;
6932	const char *ret;
6933
6934	ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
6935	if (!ret)
6936		return;
6937
6938	mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
6939	if (!mod_func)
6940		return;
6941
6942	mod_func->name = kstrdup(str, GFP_KERNEL);
6943	if (!mod_func->name) {
6944		kfree(mod_func);
6945		return;
6946	}
6947
6948	mod_func->ip = rec->ip - offset;
6949	mod_func->size = symsize;
6950
6951	mod_map->num_funcs++;
6952
6953	list_add_rcu(&mod_func->list, &mod_map->funcs);
6954}
6955
6956static struct ftrace_mod_map *
6957allocate_ftrace_mod_map(struct module *mod,
6958			unsigned long start, unsigned long end)
6959{
6960	struct ftrace_mod_map *mod_map;
6961
6962	mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
6963	if (!mod_map)
6964		return NULL;
6965
6966	mod_map->mod = mod;
6967	mod_map->start_addr = start;
6968	mod_map->end_addr = end;
6969	mod_map->num_funcs = 0;
6970
6971	INIT_LIST_HEAD_RCU(&mod_map->funcs);
6972
6973	list_add_rcu(&mod_map->list, &ftrace_mod_maps);
6974
6975	return mod_map;
6976}
6977
6978static const char *
6979ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
6980			   unsigned long addr, unsigned long *size,
6981			   unsigned long *off, char *sym)
6982{
6983	struct ftrace_mod_func *found_func =  NULL;
6984	struct ftrace_mod_func *mod_func;
6985
6986	list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
6987		if (addr >= mod_func->ip &&
6988		    addr < mod_func->ip + mod_func->size) {
6989			found_func = mod_func;
6990			break;
6991		}
6992	}
6993
6994	if (found_func) {
6995		if (size)
6996			*size = found_func->size;
6997		if (off)
6998			*off = addr - found_func->ip;
6999		if (sym)
7000			strscpy(sym, found_func->name, KSYM_NAME_LEN);
7001
7002		return found_func->name;
7003	}
7004
7005	return NULL;
7006}
7007
7008const char *
7009ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
7010		   unsigned long *off, char **modname, char *sym)
7011{
7012	struct ftrace_mod_map *mod_map;
7013	const char *ret = NULL;
7014
7015	/* mod_map is freed via call_rcu() */
7016	preempt_disable();
7017	list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7018		ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
7019		if (ret) {
7020			if (modname)
7021				*modname = mod_map->mod->name;
7022			break;
7023		}
7024	}
7025	preempt_enable();
7026
7027	return ret;
7028}
7029
7030int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7031			   char *type, char *name,
7032			   char *module_name, int *exported)
7033{
7034	struct ftrace_mod_map *mod_map;
7035	struct ftrace_mod_func *mod_func;
7036	int ret;
7037
7038	preempt_disable();
7039	list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7040
7041		if (symnum >= mod_map->num_funcs) {
7042			symnum -= mod_map->num_funcs;
7043			continue;
7044		}
7045
7046		list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7047			if (symnum > 1) {
7048				symnum--;
7049				continue;
7050			}
7051
7052			*value = mod_func->ip;
7053			*type = 'T';
7054			strscpy(name, mod_func->name, KSYM_NAME_LEN);
7055			strscpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
7056			*exported = 1;
7057			preempt_enable();
7058			return 0;
7059		}
7060		WARN_ON(1);
7061		break;
7062	}
7063	ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7064					    module_name, exported);
7065	preempt_enable();
7066	return ret;
7067}
7068
7069#else
7070static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7071				struct dyn_ftrace *rec) { }
7072static inline struct ftrace_mod_map *
7073allocate_ftrace_mod_map(struct module *mod,
7074			unsigned long start, unsigned long end)
7075{
7076	return NULL;
7077}
7078int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7079			   char *type, char *name, char *module_name,
7080			   int *exported)
7081{
7082	int ret;
7083
7084	preempt_disable();
7085	ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7086					    module_name, exported);
7087	preempt_enable();
7088	return ret;
7089}
7090#endif /* CONFIG_MODULES */
7091
7092struct ftrace_init_func {
7093	struct list_head list;
7094	unsigned long ip;
7095};
7096
7097/* Clear any init ips from hashes */
7098static void
7099clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
7100{
7101	struct ftrace_func_entry *entry;
7102
7103	entry = ftrace_lookup_ip(hash, func->ip);
7104	/*
7105	 * Do not allow this rec to match again.
7106	 * Yeah, it may waste some memory, but will be removed
7107	 * if/when the hash is modified again.
7108	 */
7109	if (entry)
7110		entry->ip = 0;
7111}
7112
7113static void
7114clear_func_from_hashes(struct ftrace_init_func *func)
7115{
7116	struct trace_array *tr;
7117
7118	mutex_lock(&trace_types_lock);
7119	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7120		if (!tr->ops || !tr->ops->func_hash)
7121			continue;
7122		mutex_lock(&tr->ops->func_hash->regex_lock);
7123		clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
7124		clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
7125		mutex_unlock(&tr->ops->func_hash->regex_lock);
7126	}
7127	mutex_unlock(&trace_types_lock);
7128}
7129
7130static void add_to_clear_hash_list(struct list_head *clear_list,
7131				   struct dyn_ftrace *rec)
7132{
7133	struct ftrace_init_func *func;
7134
7135	func = kmalloc(sizeof(*func), GFP_KERNEL);
7136	if (!func) {
7137		MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
7138		return;
7139	}
7140
7141	func->ip = rec->ip;
7142	list_add(&func->list, clear_list);
7143}
7144
7145void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
7146{
7147	unsigned long start = (unsigned long)(start_ptr);
7148	unsigned long end = (unsigned long)(end_ptr);
7149	struct ftrace_page **last_pg = &ftrace_pages_start;
7150	struct ftrace_page *tmp_page = NULL;
7151	struct ftrace_page *pg;
7152	struct dyn_ftrace *rec;
7153	struct dyn_ftrace key;
7154	struct ftrace_mod_map *mod_map = NULL;
7155	struct ftrace_init_func *func, *func_next;
7156	LIST_HEAD(clear_hash);
 
 
7157
7158	key.ip = start;
7159	key.flags = end;	/* overload flags, as it is unsigned long */
7160
7161	mutex_lock(&ftrace_lock);
7162
7163	/*
7164	 * If we are freeing module init memory, then check if
7165	 * any tracer is active. If so, we need to save a mapping of
7166	 * the module functions being freed with the address.
7167	 */
7168	if (mod && ftrace_ops_list != &ftrace_list_end)
7169		mod_map = allocate_ftrace_mod_map(mod, start, end);
7170
7171	for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
7172		if (end < pg->records[0].ip ||
7173		    start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
7174			continue;
7175 again:
7176		rec = bsearch(&key, pg->records, pg->index,
7177			      sizeof(struct dyn_ftrace),
7178			      ftrace_cmp_recs);
7179		if (!rec)
7180			continue;
7181
7182		/* rec will be cleared from hashes after ftrace_lock unlock */
7183		add_to_clear_hash_list(&clear_hash, rec);
7184
7185		if (mod_map)
7186			save_ftrace_mod_rec(mod_map, rec);
7187
7188		pg->index--;
7189		ftrace_update_tot_cnt--;
7190		if (!pg->index) {
7191			*last_pg = pg->next;
7192			pg->next = tmp_page;
7193			tmp_page = pg;
 
 
 
 
7194			pg = container_of(last_pg, struct ftrace_page, next);
7195			if (!(*last_pg))
7196				ftrace_pages = pg;
7197			continue;
7198		}
7199		memmove(rec, rec + 1,
7200			(pg->index - (rec - pg->records)) * sizeof(*rec));
7201		/* More than one function may be in this block */
7202		goto again;
7203	}
7204	mutex_unlock(&ftrace_lock);
7205
7206	list_for_each_entry_safe(func, func_next, &clear_hash, list) {
7207		clear_func_from_hashes(func);
7208		kfree(func);
7209	}
7210	/* Need to synchronize with ftrace_location_range() */
7211	if (tmp_page) {
7212		synchronize_rcu();
7213		ftrace_free_pages(tmp_page);
7214	}
7215}
7216
7217void __init ftrace_free_init_mem(void)
7218{
7219	void *start = (void *)(&__init_begin);
7220	void *end = (void *)(&__init_end);
7221
7222	ftrace_boot_snapshot();
7223
7224	ftrace_free_mem(NULL, start, end);
7225}
7226
7227int __init __weak ftrace_dyn_arch_init(void)
7228{
7229	return 0;
7230}
7231
7232void __init ftrace_init(void)
7233{
7234	extern unsigned long __start_mcount_loc[];
7235	extern unsigned long __stop_mcount_loc[];
7236	unsigned long count, flags;
7237	int ret;
7238
7239	local_irq_save(flags);
7240	ret = ftrace_dyn_arch_init();
7241	local_irq_restore(flags);
7242	if (ret)
7243		goto failed;
7244
7245	count = __stop_mcount_loc - __start_mcount_loc;
7246	if (!count) {
7247		pr_info("ftrace: No functions to be traced?\n");
7248		goto failed;
7249	}
7250
7251	pr_info("ftrace: allocating %ld entries in %ld pages\n",
7252		count, DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
7253
7254	ret = ftrace_process_locs(NULL,
7255				  __start_mcount_loc,
7256				  __stop_mcount_loc);
7257	if (ret) {
7258		pr_warn("ftrace: failed to allocate entries for functions\n");
7259		goto failed;
7260	}
7261
7262	pr_info("ftrace: allocated %ld pages with %ld groups\n",
7263		ftrace_number_of_pages, ftrace_number_of_groups);
7264
7265	last_ftrace_enabled = ftrace_enabled = 1;
7266
7267	set_ftrace_early_filters();
7268
7269	return;
7270 failed:
7271	ftrace_disabled = 1;
7272}
7273
7274/* Do nothing if arch does not support this */
7275void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
7276{
7277}
7278
7279static void ftrace_update_trampoline(struct ftrace_ops *ops)
7280{
7281	unsigned long trampoline = ops->trampoline;
7282
7283	arch_ftrace_update_trampoline(ops);
7284	if (ops->trampoline && ops->trampoline != trampoline &&
7285	    (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
7286		/* Add to kallsyms before the perf events */
7287		ftrace_add_trampoline_to_kallsyms(ops);
7288		perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
7289				   ops->trampoline, ops->trampoline_size, false,
7290				   FTRACE_TRAMPOLINE_SYM);
7291		/*
7292		 * Record the perf text poke event after the ksymbol register
7293		 * event.
7294		 */
7295		perf_event_text_poke((void *)ops->trampoline, NULL, 0,
7296				     (void *)ops->trampoline,
7297				     ops->trampoline_size);
7298	}
7299}
7300
7301void ftrace_init_trace_array(struct trace_array *tr)
7302{
7303	INIT_LIST_HEAD(&tr->func_probes);
7304	INIT_LIST_HEAD(&tr->mod_trace);
7305	INIT_LIST_HEAD(&tr->mod_notrace);
7306}
7307#else
7308
7309struct ftrace_ops global_ops = {
7310	.func			= ftrace_stub,
7311	.flags			= FTRACE_OPS_FL_INITIALIZED |
7312				  FTRACE_OPS_FL_PID,
7313};
7314
7315static int __init ftrace_nodyn_init(void)
7316{
7317	ftrace_enabled = 1;
7318	return 0;
7319}
7320core_initcall(ftrace_nodyn_init);
7321
7322static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
7323static inline void ftrace_startup_all(int command) { }
7324
7325static void ftrace_update_trampoline(struct ftrace_ops *ops)
7326{
7327}
7328
7329#endif /* CONFIG_DYNAMIC_FTRACE */
7330
7331__init void ftrace_init_global_array_ops(struct trace_array *tr)
7332{
7333	tr->ops = &global_ops;
7334	tr->ops->private = tr;
7335	ftrace_init_trace_array(tr);
7336}
7337
7338void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
7339{
7340	/* If we filter on pids, update to use the pid function */
7341	if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
7342		if (WARN_ON(tr->ops->func != ftrace_stub))
7343			printk("ftrace ops had %pS for function\n",
7344			       tr->ops->func);
7345	}
7346	tr->ops->func = func;
7347	tr->ops->private = tr;
7348}
7349
7350void ftrace_reset_array_ops(struct trace_array *tr)
7351{
7352	tr->ops->func = ftrace_stub;
7353}
7354
7355static nokprobe_inline void
7356__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7357		       struct ftrace_ops *ignored, struct ftrace_regs *fregs)
7358{
7359	struct pt_regs *regs = ftrace_get_regs(fregs);
7360	struct ftrace_ops *op;
7361	int bit;
7362
7363	/*
7364	 * The ftrace_test_and_set_recursion() will disable preemption,
7365	 * which is required since some of the ops may be dynamically
7366	 * allocated, they must be freed after a synchronize_rcu().
7367	 */
7368	bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7369	if (bit < 0)
7370		return;
7371
7372	do_for_each_ftrace_op(op, ftrace_ops_list) {
7373		/* Stub functions don't need to be called nor tested */
7374		if (op->flags & FTRACE_OPS_FL_STUB)
7375			continue;
7376		/*
7377		 * Check the following for each ops before calling their func:
7378		 *  if RCU flag is set, then rcu_is_watching() must be true
7379		 *  Otherwise test if the ip matches the ops filter
7380		 *
7381		 * If any of the above fails then the op->func() is not executed.
7382		 */
7383		if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
7384		    ftrace_ops_test(op, ip, regs)) {
7385			if (FTRACE_WARN_ON(!op->func)) {
7386				pr_warn("op=%p %pS\n", op, op);
7387				goto out;
7388			}
7389			op->func(ip, parent_ip, op, fregs);
7390		}
7391	} while_for_each_ftrace_op(op);
7392out:
7393	trace_clear_recursion(bit);
7394}
7395
7396/*
7397 * Some archs only support passing ip and parent_ip. Even though
7398 * the list function ignores the op parameter, we do not want any
7399 * C side effects, where a function is called without the caller
7400 * sending a third parameter.
7401 * Archs are to support both the regs and ftrace_ops at the same time.
7402 * If they support ftrace_ops, it is assumed they support regs.
7403 * If call backs want to use regs, they must either check for regs
7404 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7405 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7406 * An architecture can pass partial regs with ftrace_ops and still
7407 * set the ARCH_SUPPORTS_FTRACE_OPS.
7408 *
7409 * In vmlinux.lds.h, ftrace_ops_list_func() is defined to be
7410 * arch_ftrace_ops_list_func.
7411 */
7412#if ARCH_SUPPORTS_FTRACE_OPS
7413void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7414			       struct ftrace_ops *op, struct ftrace_regs *fregs)
7415{
7416	__ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
7417}
7418#else
7419void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
7420{
7421	__ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7422}
7423#endif
7424NOKPROBE_SYMBOL(arch_ftrace_ops_list_func);
7425
7426/*
7427 * If there's only one function registered but it does not support
7428 * recursion, needs RCU protection, then this function will be called
7429 * by the mcount trampoline.
7430 */
7431static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7432				   struct ftrace_ops *op, struct ftrace_regs *fregs)
7433{
7434	int bit;
7435
7436	bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7437	if (bit < 0)
7438		return;
7439
7440	if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7441		op->func(ip, parent_ip, op, fregs);
7442
7443	trace_clear_recursion(bit);
7444}
7445NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7446
7447/**
7448 * ftrace_ops_get_func - get the function a trampoline should call
7449 * @ops: the ops to get the function for
7450 *
7451 * Normally the mcount trampoline will call the ops->func, but there
7452 * are times that it should not. For example, if the ops does not
7453 * have its own recursion protection, then it should call the
7454 * ftrace_ops_assist_func() instead.
7455 *
7456 * Returns: the function that the trampoline should call for @ops.
7457 */
7458ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7459{
7460	/*
7461	 * If the function does not handle recursion or needs to be RCU safe,
7462	 * then we need to call the assist handler.
7463	 */
7464	if (ops->flags & (FTRACE_OPS_FL_RECURSION |
7465			  FTRACE_OPS_FL_RCU))
7466		return ftrace_ops_assist_func;
7467
7468	return ops->func;
7469}
7470
7471static void
7472ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7473				     struct task_struct *prev,
7474				     struct task_struct *next,
7475				     unsigned int prev_state)
7476{
7477	struct trace_array *tr = data;
7478	struct trace_pid_list *pid_list;
7479	struct trace_pid_list *no_pid_list;
7480
7481	pid_list = rcu_dereference_sched(tr->function_pids);
7482	no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7483
7484	if (trace_ignore_this_task(pid_list, no_pid_list, next))
7485		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7486			       FTRACE_PID_IGNORE);
7487	else
7488		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7489			       next->pid);
7490}
7491
7492static void
7493ftrace_pid_follow_sched_process_fork(void *data,
7494				     struct task_struct *self,
7495				     struct task_struct *task)
7496{
7497	struct trace_pid_list *pid_list;
7498	struct trace_array *tr = data;
7499
7500	pid_list = rcu_dereference_sched(tr->function_pids);
7501	trace_filter_add_remove_task(pid_list, self, task);
7502
7503	pid_list = rcu_dereference_sched(tr->function_no_pids);
7504	trace_filter_add_remove_task(pid_list, self, task);
7505}
7506
7507static void
7508ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7509{
7510	struct trace_pid_list *pid_list;
7511	struct trace_array *tr = data;
7512
7513	pid_list = rcu_dereference_sched(tr->function_pids);
7514	trace_filter_add_remove_task(pid_list, NULL, task);
7515
7516	pid_list = rcu_dereference_sched(tr->function_no_pids);
7517	trace_filter_add_remove_task(pid_list, NULL, task);
7518}
7519
7520void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7521{
7522	if (enable) {
7523		register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7524						  tr);
7525		register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7526						  tr);
7527	} else {
7528		unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7529						    tr);
7530		unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7531						    tr);
7532	}
7533}
7534
7535static void clear_ftrace_pids(struct trace_array *tr, int type)
7536{
7537	struct trace_pid_list *pid_list;
7538	struct trace_pid_list *no_pid_list;
7539	int cpu;
7540
7541	pid_list = rcu_dereference_protected(tr->function_pids,
7542					     lockdep_is_held(&ftrace_lock));
7543	no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7544						lockdep_is_held(&ftrace_lock));
7545
7546	/* Make sure there's something to do */
7547	if (!pid_type_enabled(type, pid_list, no_pid_list))
7548		return;
7549
7550	/* See if the pids still need to be checked after this */
7551	if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7552		unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7553		for_each_possible_cpu(cpu)
7554			per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7555	}
7556
7557	if (type & TRACE_PIDS)
7558		rcu_assign_pointer(tr->function_pids, NULL);
7559
7560	if (type & TRACE_NO_PIDS)
7561		rcu_assign_pointer(tr->function_no_pids, NULL);
7562
7563	/* Wait till all users are no longer using pid filtering */
7564	synchronize_rcu();
7565
7566	if ((type & TRACE_PIDS) && pid_list)
7567		trace_pid_list_free(pid_list);
7568
7569	if ((type & TRACE_NO_PIDS) && no_pid_list)
7570		trace_pid_list_free(no_pid_list);
7571}
7572
7573void ftrace_clear_pids(struct trace_array *tr)
7574{
7575	mutex_lock(&ftrace_lock);
7576
7577	clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7578
7579	mutex_unlock(&ftrace_lock);
7580}
7581
7582static void ftrace_pid_reset(struct trace_array *tr, int type)
7583{
7584	mutex_lock(&ftrace_lock);
7585	clear_ftrace_pids(tr, type);
7586
7587	ftrace_update_pid_func();
7588	ftrace_startup_all(0);
7589
7590	mutex_unlock(&ftrace_lock);
7591}
7592
7593/* Greater than any max PID */
7594#define FTRACE_NO_PIDS		(void *)(PID_MAX_LIMIT + 1)
7595
7596static void *fpid_start(struct seq_file *m, loff_t *pos)
7597	__acquires(RCU)
7598{
7599	struct trace_pid_list *pid_list;
7600	struct trace_array *tr = m->private;
7601
7602	mutex_lock(&ftrace_lock);
7603	rcu_read_lock_sched();
7604
7605	pid_list = rcu_dereference_sched(tr->function_pids);
7606
7607	if (!pid_list)
7608		return !(*pos) ? FTRACE_NO_PIDS : NULL;
7609
7610	return trace_pid_start(pid_list, pos);
7611}
7612
7613static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7614{
7615	struct trace_array *tr = m->private;
7616	struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7617
7618	if (v == FTRACE_NO_PIDS) {
7619		(*pos)++;
7620		return NULL;
7621	}
7622	return trace_pid_next(pid_list, v, pos);
7623}
7624
7625static void fpid_stop(struct seq_file *m, void *p)
7626	__releases(RCU)
7627{
7628	rcu_read_unlock_sched();
7629	mutex_unlock(&ftrace_lock);
7630}
7631
7632static int fpid_show(struct seq_file *m, void *v)
7633{
7634	if (v == FTRACE_NO_PIDS) {
7635		seq_puts(m, "no pid\n");
7636		return 0;
7637	}
7638
7639	return trace_pid_show(m, v);
7640}
7641
7642static const struct seq_operations ftrace_pid_sops = {
7643	.start = fpid_start,
7644	.next = fpid_next,
7645	.stop = fpid_stop,
7646	.show = fpid_show,
7647};
7648
7649static void *fnpid_start(struct seq_file *m, loff_t *pos)
7650	__acquires(RCU)
7651{
7652	struct trace_pid_list *pid_list;
7653	struct trace_array *tr = m->private;
7654
7655	mutex_lock(&ftrace_lock);
7656	rcu_read_lock_sched();
7657
7658	pid_list = rcu_dereference_sched(tr->function_no_pids);
7659
7660	if (!pid_list)
7661		return !(*pos) ? FTRACE_NO_PIDS : NULL;
7662
7663	return trace_pid_start(pid_list, pos);
7664}
7665
7666static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7667{
7668	struct trace_array *tr = m->private;
7669	struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7670
7671	if (v == FTRACE_NO_PIDS) {
7672		(*pos)++;
7673		return NULL;
7674	}
7675	return trace_pid_next(pid_list, v, pos);
7676}
7677
7678static const struct seq_operations ftrace_no_pid_sops = {
7679	.start = fnpid_start,
7680	.next = fnpid_next,
7681	.stop = fpid_stop,
7682	.show = fpid_show,
7683};
7684
7685static int pid_open(struct inode *inode, struct file *file, int type)
7686{
7687	const struct seq_operations *seq_ops;
7688	struct trace_array *tr = inode->i_private;
7689	struct seq_file *m;
7690	int ret = 0;
7691
7692	ret = tracing_check_open_get_tr(tr);
7693	if (ret)
7694		return ret;
7695
7696	if ((file->f_mode & FMODE_WRITE) &&
7697	    (file->f_flags & O_TRUNC))
7698		ftrace_pid_reset(tr, type);
7699
7700	switch (type) {
7701	case TRACE_PIDS:
7702		seq_ops = &ftrace_pid_sops;
7703		break;
7704	case TRACE_NO_PIDS:
7705		seq_ops = &ftrace_no_pid_sops;
7706		break;
7707	default:
7708		trace_array_put(tr);
7709		WARN_ON_ONCE(1);
7710		return -EINVAL;
7711	}
7712
7713	ret = seq_open(file, seq_ops);
7714	if (ret < 0) {
7715		trace_array_put(tr);
7716	} else {
7717		m = file->private_data;
7718		/* copy tr over to seq ops */
7719		m->private = tr;
7720	}
7721
7722	return ret;
7723}
7724
7725static int
7726ftrace_pid_open(struct inode *inode, struct file *file)
7727{
7728	return pid_open(inode, file, TRACE_PIDS);
7729}
7730
7731static int
7732ftrace_no_pid_open(struct inode *inode, struct file *file)
7733{
7734	return pid_open(inode, file, TRACE_NO_PIDS);
7735}
7736
7737static void ignore_task_cpu(void *data)
7738{
7739	struct trace_array *tr = data;
7740	struct trace_pid_list *pid_list;
7741	struct trace_pid_list *no_pid_list;
7742
7743	/*
7744	 * This function is called by on_each_cpu() while the
7745	 * event_mutex is held.
7746	 */
7747	pid_list = rcu_dereference_protected(tr->function_pids,
7748					     mutex_is_locked(&ftrace_lock));
7749	no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7750						mutex_is_locked(&ftrace_lock));
7751
7752	if (trace_ignore_this_task(pid_list, no_pid_list, current))
7753		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7754			       FTRACE_PID_IGNORE);
7755	else
7756		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7757			       current->pid);
7758}
7759
7760static ssize_t
7761pid_write(struct file *filp, const char __user *ubuf,
7762	  size_t cnt, loff_t *ppos, int type)
7763{
7764	struct seq_file *m = filp->private_data;
7765	struct trace_array *tr = m->private;
7766	struct trace_pid_list *filtered_pids;
7767	struct trace_pid_list *other_pids;
7768	struct trace_pid_list *pid_list;
7769	ssize_t ret;
7770
7771	if (!cnt)
7772		return 0;
7773
7774	mutex_lock(&ftrace_lock);
7775
7776	switch (type) {
7777	case TRACE_PIDS:
7778		filtered_pids = rcu_dereference_protected(tr->function_pids,
7779					     lockdep_is_held(&ftrace_lock));
7780		other_pids = rcu_dereference_protected(tr->function_no_pids,
7781					     lockdep_is_held(&ftrace_lock));
7782		break;
7783	case TRACE_NO_PIDS:
7784		filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7785					     lockdep_is_held(&ftrace_lock));
7786		other_pids = rcu_dereference_protected(tr->function_pids,
7787					     lockdep_is_held(&ftrace_lock));
7788		break;
7789	default:
7790		ret = -EINVAL;
7791		WARN_ON_ONCE(1);
7792		goto out;
7793	}
7794
7795	ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7796	if (ret < 0)
7797		goto out;
7798
7799	switch (type) {
7800	case TRACE_PIDS:
7801		rcu_assign_pointer(tr->function_pids, pid_list);
7802		break;
7803	case TRACE_NO_PIDS:
7804		rcu_assign_pointer(tr->function_no_pids, pid_list);
7805		break;
7806	}
7807
7808
7809	if (filtered_pids) {
7810		synchronize_rcu();
7811		trace_pid_list_free(filtered_pids);
7812	} else if (pid_list && !other_pids) {
7813		/* Register a probe to set whether to ignore the tracing of a task */
7814		register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7815	}
7816
7817	/*
7818	 * Ignoring of pids is done at task switch. But we have to
7819	 * check for those tasks that are currently running.
7820	 * Always do this in case a pid was appended or removed.
7821	 */
7822	on_each_cpu(ignore_task_cpu, tr, 1);
7823
7824	ftrace_update_pid_func();
7825	ftrace_startup_all(0);
7826 out:
7827	mutex_unlock(&ftrace_lock);
7828
7829	if (ret > 0)
7830		*ppos += ret;
7831
7832	return ret;
7833}
7834
7835static ssize_t
7836ftrace_pid_write(struct file *filp, const char __user *ubuf,
7837		 size_t cnt, loff_t *ppos)
7838{
7839	return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
7840}
7841
7842static ssize_t
7843ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
7844		    size_t cnt, loff_t *ppos)
7845{
7846	return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
7847}
7848
7849static int
7850ftrace_pid_release(struct inode *inode, struct file *file)
7851{
7852	struct trace_array *tr = inode->i_private;
7853
7854	trace_array_put(tr);
7855
7856	return seq_release(inode, file);
7857}
7858
7859static const struct file_operations ftrace_pid_fops = {
7860	.open		= ftrace_pid_open,
7861	.write		= ftrace_pid_write,
7862	.read		= seq_read,
7863	.llseek		= tracing_lseek,
7864	.release	= ftrace_pid_release,
7865};
7866
7867static const struct file_operations ftrace_no_pid_fops = {
7868	.open		= ftrace_no_pid_open,
7869	.write		= ftrace_no_pid_write,
7870	.read		= seq_read,
7871	.llseek		= tracing_lseek,
7872	.release	= ftrace_pid_release,
7873};
7874
7875void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
7876{
7877	trace_create_file("set_ftrace_pid", TRACE_MODE_WRITE, d_tracer,
7878			    tr, &ftrace_pid_fops);
7879	trace_create_file("set_ftrace_notrace_pid", TRACE_MODE_WRITE,
7880			  d_tracer, tr, &ftrace_no_pid_fops);
7881}
7882
7883void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
7884					 struct dentry *d_tracer)
7885{
7886	/* Only the top level directory has the dyn_tracefs and profile */
7887	WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
7888
7889	ftrace_init_dyn_tracefs(d_tracer);
7890	ftrace_profile_tracefs(d_tracer);
7891}
7892
7893/**
7894 * ftrace_kill - kill ftrace
7895 *
7896 * This function should be used by panic code. It stops ftrace
7897 * but in a not so nice way. If you need to simply kill ftrace
7898 * from a non-atomic section, use ftrace_kill.
7899 */
7900void ftrace_kill(void)
7901{
7902	ftrace_disabled = 1;
7903	ftrace_enabled = 0;
7904	ftrace_trace_function = ftrace_stub;
7905}
7906
7907/**
7908 * ftrace_is_dead - Test if ftrace is dead or not.
7909 *
7910 * Returns: 1 if ftrace is "dead", zero otherwise.
7911 */
7912int ftrace_is_dead(void)
7913{
7914	return ftrace_disabled;
7915}
7916
7917#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
7918/*
7919 * When registering ftrace_ops with IPMODIFY, it is necessary to make sure
7920 * it doesn't conflict with any direct ftrace_ops. If there is existing
7921 * direct ftrace_ops on a kernel function being patched, call
7922 * FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER on it to enable sharing.
7923 *
7924 * @ops:     ftrace_ops being registered.
7925 *
7926 * Returns:
7927 *         0 on success;
7928 *         Negative on failure.
7929 */
7930static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
7931{
7932	struct ftrace_func_entry *entry;
7933	struct ftrace_hash *hash;
7934	struct ftrace_ops *op;
7935	int size, i, ret;
7936
7937	lockdep_assert_held_once(&direct_mutex);
7938
7939	if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
7940		return 0;
7941
7942	hash = ops->func_hash->filter_hash;
7943	size = 1 << hash->size_bits;
7944	for (i = 0; i < size; i++) {
7945		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
7946			unsigned long ip = entry->ip;
7947			bool found_op = false;
7948
7949			mutex_lock(&ftrace_lock);
7950			do_for_each_ftrace_op(op, ftrace_ops_list) {
7951				if (!(op->flags & FTRACE_OPS_FL_DIRECT))
7952					continue;
7953				if (ops_references_ip(op, ip)) {
7954					found_op = true;
7955					break;
7956				}
7957			} while_for_each_ftrace_op(op);
7958			mutex_unlock(&ftrace_lock);
7959
7960			if (found_op) {
7961				if (!op->ops_func)
7962					return -EBUSY;
7963
7964				ret = op->ops_func(op, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER);
7965				if (ret)
7966					return ret;
7967			}
7968		}
7969	}
7970
7971	return 0;
7972}
7973
7974/*
7975 * Similar to prepare_direct_functions_for_ipmodify, clean up after ops
7976 * with IPMODIFY is unregistered. The cleanup is optional for most DIRECT
7977 * ops.
7978 */
7979static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
7980{
7981	struct ftrace_func_entry *entry;
7982	struct ftrace_hash *hash;
7983	struct ftrace_ops *op;
7984	int size, i;
7985
7986	if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
7987		return;
7988
7989	mutex_lock(&direct_mutex);
7990
7991	hash = ops->func_hash->filter_hash;
7992	size = 1 << hash->size_bits;
7993	for (i = 0; i < size; i++) {
7994		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
7995			unsigned long ip = entry->ip;
7996			bool found_op = false;
7997
7998			mutex_lock(&ftrace_lock);
7999			do_for_each_ftrace_op(op, ftrace_ops_list) {
8000				if (!(op->flags & FTRACE_OPS_FL_DIRECT))
8001					continue;
8002				if (ops_references_ip(op, ip)) {
8003					found_op = true;
8004					break;
8005				}
8006			} while_for_each_ftrace_op(op);
8007			mutex_unlock(&ftrace_lock);
8008
8009			/* The cleanup is optional, ignore any errors */
8010			if (found_op && op->ops_func)
8011				op->ops_func(op, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER);
8012		}
8013	}
8014	mutex_unlock(&direct_mutex);
8015}
8016
8017#define lock_direct_mutex()	mutex_lock(&direct_mutex)
8018#define unlock_direct_mutex()	mutex_unlock(&direct_mutex)
8019
8020#else  /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8021
8022static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
8023{
8024	return 0;
8025}
8026
8027static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
8028{
8029}
8030
8031#define lock_direct_mutex()	do { } while (0)
8032#define unlock_direct_mutex()	do { } while (0)
8033
8034#endif  /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8035
8036/*
8037 * Similar to register_ftrace_function, except we don't lock direct_mutex.
8038 */
8039static int register_ftrace_function_nolock(struct ftrace_ops *ops)
8040{
8041	int ret;
8042
8043	ftrace_ops_init(ops);
8044
8045	mutex_lock(&ftrace_lock);
8046
8047	ret = ftrace_startup(ops, 0);
8048
8049	mutex_unlock(&ftrace_lock);
8050
8051	return ret;
8052}
8053
8054/**
8055 * register_ftrace_function - register a function for profiling
8056 * @ops:	ops structure that holds the function for profiling.
8057 *
8058 * Register a function to be called by all functions in the
8059 * kernel.
8060 *
8061 * Note: @ops->func and all the functions it calls must be labeled
8062 *       with "notrace", otherwise it will go into a
8063 *       recursive loop.
8064 */
8065int register_ftrace_function(struct ftrace_ops *ops)
8066{
8067	int ret;
8068
8069	lock_direct_mutex();
8070	ret = prepare_direct_functions_for_ipmodify(ops);
8071	if (ret < 0)
8072		goto out_unlock;
8073
8074	ret = register_ftrace_function_nolock(ops);
8075
8076out_unlock:
8077	unlock_direct_mutex();
8078	return ret;
8079}
8080EXPORT_SYMBOL_GPL(register_ftrace_function);
8081
8082/**
8083 * unregister_ftrace_function - unregister a function for profiling.
8084 * @ops:	ops structure that holds the function to unregister
8085 *
8086 * Unregister a function that was added to be called by ftrace profiling.
8087 */
8088int unregister_ftrace_function(struct ftrace_ops *ops)
8089{
8090	int ret;
8091
8092	mutex_lock(&ftrace_lock);
8093	ret = ftrace_shutdown(ops, 0);
8094	mutex_unlock(&ftrace_lock);
8095
8096	cleanup_direct_functions_after_ipmodify(ops);
8097	return ret;
8098}
8099EXPORT_SYMBOL_GPL(unregister_ftrace_function);
8100
8101static int symbols_cmp(const void *a, const void *b)
8102{
8103	const char **str_a = (const char **) a;
8104	const char **str_b = (const char **) b;
8105
8106	return strcmp(*str_a, *str_b);
8107}
8108
8109struct kallsyms_data {
8110	unsigned long *addrs;
8111	const char **syms;
8112	size_t cnt;
8113	size_t found;
8114};
8115
8116/* This function gets called for all kernel and module symbols
8117 * and returns 1 in case we resolved all the requested symbols,
8118 * 0 otherwise.
8119 */
8120static int kallsyms_callback(void *data, const char *name, unsigned long addr)
 
8121{
8122	struct kallsyms_data *args = data;
8123	const char **sym;
8124	int idx;
8125
8126	sym = bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp);
8127	if (!sym)
8128		return 0;
8129
8130	idx = sym - args->syms;
8131	if (args->addrs[idx])
8132		return 0;
8133
8134	if (!ftrace_location(addr))
8135		return 0;
8136
8137	args->addrs[idx] = addr;
8138	args->found++;
8139	return args->found == args->cnt ? 1 : 0;
8140}
8141
8142/**
8143 * ftrace_lookup_symbols - Lookup addresses for array of symbols
8144 *
8145 * @sorted_syms: array of symbols pointers symbols to resolve,
8146 * must be alphabetically sorted
8147 * @cnt: number of symbols/addresses in @syms/@addrs arrays
8148 * @addrs: array for storing resulting addresses
8149 *
8150 * This function looks up addresses for array of symbols provided in
8151 * @syms array (must be alphabetically sorted) and stores them in
8152 * @addrs array, which needs to be big enough to store at least @cnt
8153 * addresses.
8154 *
8155 * Returns: 0 if all provided symbols are found, -ESRCH otherwise.
 
8156 */
8157int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
8158{
8159	struct kallsyms_data args;
8160	int found_all;
8161
8162	memset(addrs, 0, sizeof(*addrs) * cnt);
8163	args.addrs = addrs;
8164	args.syms = sorted_syms;
8165	args.cnt = cnt;
8166	args.found = 0;
8167
8168	found_all = kallsyms_on_each_symbol(kallsyms_callback, &args);
8169	if (found_all)
8170		return 0;
8171	found_all = module_kallsyms_on_each_symbol(NULL, kallsyms_callback, &args);
8172	return found_all ? 0 : -ESRCH;
8173}
8174
8175#ifdef CONFIG_SYSCTL
8176
8177#ifdef CONFIG_DYNAMIC_FTRACE
8178static void ftrace_startup_sysctl(void)
8179{
8180	int command;
8181
8182	if (unlikely(ftrace_disabled))
8183		return;
8184
8185	/* Force update next time */
8186	saved_ftrace_func = NULL;
8187	/* ftrace_start_up is true if we want ftrace running */
8188	if (ftrace_start_up) {
8189		command = FTRACE_UPDATE_CALLS;
8190		if (ftrace_graph_active)
8191			command |= FTRACE_START_FUNC_RET;
8192		ftrace_startup_enable(command);
8193	}
8194}
8195
8196static void ftrace_shutdown_sysctl(void)
8197{
8198	int command;
8199
8200	if (unlikely(ftrace_disabled))
8201		return;
8202
8203	/* ftrace_start_up is true if ftrace is running */
8204	if (ftrace_start_up) {
8205		command = FTRACE_DISABLE_CALLS;
8206		if (ftrace_graph_active)
8207			command |= FTRACE_STOP_FUNC_RET;
8208		ftrace_run_update_code(command);
8209	}
8210}
8211#else
8212# define ftrace_startup_sysctl()       do { } while (0)
8213# define ftrace_shutdown_sysctl()      do { } while (0)
8214#endif /* CONFIG_DYNAMIC_FTRACE */
8215
8216static bool is_permanent_ops_registered(void)
8217{
8218	struct ftrace_ops *op;
8219
8220	do_for_each_ftrace_op(op, ftrace_ops_list) {
8221		if (op->flags & FTRACE_OPS_FL_PERMANENT)
8222			return true;
8223	} while_for_each_ftrace_op(op);
8224
8225	return false;
8226}
8227
8228static int
8229ftrace_enable_sysctl(struct ctl_table *table, int write,
8230		     void *buffer, size_t *lenp, loff_t *ppos)
8231{
8232	int ret = -ENODEV;
8233
8234	mutex_lock(&ftrace_lock);
8235
8236	if (unlikely(ftrace_disabled))
8237		goto out;
8238
8239	ret = proc_dointvec(table, write, buffer, lenp, ppos);
8240
8241	if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
8242		goto out;
8243
8244	if (ftrace_enabled) {
8245
8246		/* we are starting ftrace again */
8247		if (rcu_dereference_protected(ftrace_ops_list,
8248			lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
8249			update_ftrace_function();
8250
8251		ftrace_startup_sysctl();
8252
8253	} else {
8254		if (is_permanent_ops_registered()) {
8255			ftrace_enabled = true;
8256			ret = -EBUSY;
8257			goto out;
8258		}
8259
8260		/* stopping ftrace calls (just send to ftrace_stub) */
8261		ftrace_trace_function = ftrace_stub;
8262
8263		ftrace_shutdown_sysctl();
8264	}
8265
8266	last_ftrace_enabled = !!ftrace_enabled;
8267 out:
8268	mutex_unlock(&ftrace_lock);
8269	return ret;
8270}
8271
8272static struct ctl_table ftrace_sysctls[] = {
8273	{
8274		.procname       = "ftrace_enabled",
8275		.data           = &ftrace_enabled,
8276		.maxlen         = sizeof(int),
8277		.mode           = 0644,
8278		.proc_handler   = ftrace_enable_sysctl,
8279	},
8280	{}
8281};
8282
8283static int __init ftrace_sysctl_init(void)
8284{
8285	register_sysctl_init("kernel", ftrace_sysctls);
8286	return 0;
8287}
8288late_initcall(ftrace_sysctl_init);
8289#endif