1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Infrastructure for profiling code inserted by 'gcc -pg'.
   4 *
   5 * Copyright (C) 2007-2008 Steven Rostedt <srostedt@redhat.com>
   6 * Copyright (C) 2004-2008 Ingo Molnar <mingo@redhat.com>
   7 *
   8 * Originally ported from the -rt patch by:
   9 *   Copyright (C) 2007 Arnaldo Carvalho de Melo <acme@redhat.com>
  10 *
  11 * Based on code in the latency_tracer, that is:
  12 *
  13 *  Copyright (C) 2004-2006 Ingo Molnar
  14 *  Copyright (C) 2004 Nadia Yvette Chambers
  15 */
  16
  17#include <linux/stop_machine.h>
  18#include <linux/clocksource.h>
  19#include <linux/sched/task.h>
  20#include <linux/kallsyms.h>
  21#include <linux/security.h>
  22#include <linux/seq_file.h>
  23#include <linux/tracefs.h>
  24#include <linux/hardirq.h>
  25#include <linux/kthread.h>
  26#include <linux/uaccess.h>
  27#include <linux/bsearch.h>
  28#include <linux/module.h>
  29#include <linux/ftrace.h>
  30#include <linux/sysctl.h>
  31#include <linux/slab.h>
  32#include <linux/ctype.h>
  33#include <linux/sort.h>
  34#include <linux/list.h>
  35#include <linux/hash.h>
  36#include <linux/rcupdate.h>
  37#include <linux/kprobes.h>
  38
  39#include <trace/events/sched.h>
  40
  41#include <asm/sections.h>
  42#include <asm/setup.h>
  43
  44#include "ftrace_internal.h"
  45#include "trace_output.h"
  46#include "trace_stat.h"
  47
  48#define FTRACE_INVALID_FUNCTION		"__ftrace_invalid_address__"
  49
  50#define FTRACE_WARN_ON(cond)			\
  51	({					\
  52		int ___r = cond;		\
  53		if (WARN_ON(___r))		\
  54			ftrace_kill();		\
  55		___r;				\
  56	})
  57
  58#define FTRACE_WARN_ON_ONCE(cond)		\
  59	({					\
  60		int ___r = cond;		\
  61		if (WARN_ON_ONCE(___r))		\
  62			ftrace_kill();		\
  63		___r;				\
  64	})
  65
  66/* hash bits for specific function selection */
  67#define FTRACE_HASH_DEFAULT_BITS 10
  68#define FTRACE_HASH_MAX_BITS 12
  69
  70#ifdef CONFIG_DYNAMIC_FTRACE
  71#define INIT_OPS_HASH(opsname)	\
  72	.func_hash		= &opsname.local_hash,			\
  73	.local_hash.regex_lock	= __MUTEX_INITIALIZER(opsname.local_hash.regex_lock),
  74#else
  75#define INIT_OPS_HASH(opsname)
  76#endif
  77
  78enum {
  79	FTRACE_MODIFY_ENABLE_FL		= (1 << 0),
  80	FTRACE_MODIFY_MAY_SLEEP_FL	= (1 << 1),
  81};
  82
  83struct ftrace_ops ftrace_list_end __read_mostly = {
  84	.func		= ftrace_stub,
  85	.flags		= FTRACE_OPS_FL_STUB,
  86	INIT_OPS_HASH(ftrace_list_end)
  87};
  88
  89/* ftrace_enabled is a method to turn ftrace on or off */
  90int ftrace_enabled __read_mostly;
  91static int __maybe_unused last_ftrace_enabled;
  92
  93/* Current function tracing op */
  94struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
  95/* What to set function_trace_op to */
  96static struct ftrace_ops *set_function_trace_op;
  97
  98static bool ftrace_pids_enabled(struct ftrace_ops *ops)
  99{
 100	struct trace_array *tr;
 101
 102	if (!(ops->flags & FTRACE_OPS_FL_PID) || !ops->private)
 103		return false;
 104
 105	tr = ops->private;
 106
 107	return tr->function_pids != NULL || tr->function_no_pids != NULL;
 108}
 109
 110static void ftrace_update_trampoline(struct ftrace_ops *ops);
 111
 112/*
 113 * ftrace_disabled is set when an anomaly is discovered.
 114 * ftrace_disabled is much stronger than ftrace_enabled.
 115 */
 116static int ftrace_disabled __read_mostly;
 117
 118DEFINE_MUTEX(ftrace_lock);
 119
 120struct ftrace_ops __rcu *ftrace_ops_list __read_mostly = &ftrace_list_end;
 121ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub;
 122struct ftrace_ops global_ops;
 123
 124/* Defined by vmlinux.lds.h see the comment above arch_ftrace_ops_list_func for details */
 125void ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
 126			  struct ftrace_ops *op, struct ftrace_regs *fregs);
 
 
 
 
 
 127
 128static inline void ftrace_ops_init(struct ftrace_ops *ops)
 129{
 130#ifdef CONFIG_DYNAMIC_FTRACE
 131	if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED)) {
 132		mutex_init(&ops->local_hash.regex_lock);
 133		ops->func_hash = &ops->local_hash;
 134		ops->flags |= FTRACE_OPS_FL_INITIALIZED;
 135	}
 136#endif
 137}
 138
 139static void ftrace_pid_func(unsigned long ip, unsigned long parent_ip,
 140			    struct ftrace_ops *op, struct ftrace_regs *fregs)
 141{
 142	struct trace_array *tr = op->private;
 143	int pid;
 144
 145	if (tr) {
 146		pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
 147		if (pid == FTRACE_PID_IGNORE)
 148			return;
 149		if (pid != FTRACE_PID_TRACE &&
 150		    pid != current->pid)
 151			return;
 152	}
 153
 154	op->saved_func(ip, parent_ip, op, fregs);
 155}
 156
 157static void ftrace_sync_ipi(void *data)
 158{
 159	/* Probably not needed, but do it anyway */
 160	smp_rmb();
 161}
 162
 163static ftrace_func_t ftrace_ops_get_list_func(struct ftrace_ops *ops)
 164{
 165	/*
 166	 * If this is a dynamic or RCU ops, or we force list func,
 167	 * then it needs to call the list anyway.
 168	 */
 169	if (ops->flags & (FTRACE_OPS_FL_DYNAMIC | FTRACE_OPS_FL_RCU) ||
 170	    FTRACE_FORCE_LIST_FUNC)
 171		return ftrace_ops_list_func;
 172
 173	return ftrace_ops_get_func(ops);
 174}
 175
 176static void update_ftrace_function(void)
 177{
 178	ftrace_func_t func;
 179
 180	/*
 181	 * Prepare the ftrace_ops that the arch callback will use.
 182	 * If there's only one ftrace_ops registered, the ftrace_ops_list
 183	 * will point to the ops we want.
 184	 */
 185	set_function_trace_op = rcu_dereference_protected(ftrace_ops_list,
 186						lockdep_is_held(&ftrace_lock));
 187
 188	/* If there's no ftrace_ops registered, just call the stub function */
 189	if (set_function_trace_op == &ftrace_list_end) {
 190		func = ftrace_stub;
 191
 192	/*
 193	 * If we are at the end of the list and this ops is
 194	 * recursion safe and not dynamic and the arch supports passing ops,
 195	 * then have the mcount trampoline call the function directly.
 196	 */
 197	} else if (rcu_dereference_protected(ftrace_ops_list->next,
 198			lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
 199		func = ftrace_ops_get_list_func(ftrace_ops_list);
 200
 201	} else {
 202		/* Just use the default ftrace_ops */
 203		set_function_trace_op = &ftrace_list_end;
 204		func = ftrace_ops_list_func;
 205	}
 206
 207	update_function_graph_func();
 208
 209	/* If there's no change, then do nothing more here */
 210	if (ftrace_trace_function == func)
 211		return;
 212
 213	/*
 214	 * If we are using the list function, it doesn't care
 215	 * about the function_trace_ops.
 216	 */
 217	if (func == ftrace_ops_list_func) {
 218		ftrace_trace_function = func;
 219		/*
 220		 * Don't even bother setting function_trace_ops,
 221		 * it would be racy to do so anyway.
 222		 */
 223		return;
 224	}
 225
 226#ifndef CONFIG_DYNAMIC_FTRACE
 227	/*
 228	 * For static tracing, we need to be a bit more careful.
 229	 * The function change takes affect immediately. Thus,
 230	 * we need to coordinate the setting of the function_trace_ops
 231	 * with the setting of the ftrace_trace_function.
 232	 *
 233	 * Set the function to the list ops, which will call the
 234	 * function we want, albeit indirectly, but it handles the
 235	 * ftrace_ops and doesn't depend on function_trace_op.
 236	 */
 237	ftrace_trace_function = ftrace_ops_list_func;
 238	/*
 239	 * Make sure all CPUs see this. Yes this is slow, but static
 240	 * tracing is slow and nasty to have enabled.
 241	 */
 242	synchronize_rcu_tasks_rude();
 243	/* Now all cpus are using the list ops. */
 244	function_trace_op = set_function_trace_op;
 245	/* Make sure the function_trace_op is visible on all CPUs */
 246	smp_wmb();
 247	/* Nasty way to force a rmb on all cpus */
 248	smp_call_function(ftrace_sync_ipi, NULL, 1);
 249	/* OK, we are all set to update the ftrace_trace_function now! */
 250#endif /* !CONFIG_DYNAMIC_FTRACE */
 251
 252	ftrace_trace_function = func;
 253}
 254
 255static void add_ftrace_ops(struct ftrace_ops __rcu **list,
 256			   struct ftrace_ops *ops)
 257{
 258	rcu_assign_pointer(ops->next, *list);
 259
 260	/*
 261	 * We are entering ops into the list but another
 262	 * CPU might be walking that list. We need to make sure
 263	 * the ops->next pointer is valid before another CPU sees
 264	 * the ops pointer included into the list.
 265	 */
 266	rcu_assign_pointer(*list, ops);
 267}
 268
 269static int remove_ftrace_ops(struct ftrace_ops __rcu **list,
 270			     struct ftrace_ops *ops)
 271{
 272	struct ftrace_ops **p;
 273
 274	/*
 275	 * If we are removing the last function, then simply point
 276	 * to the ftrace_stub.
 277	 */
 278	if (rcu_dereference_protected(*list,
 279			lockdep_is_held(&ftrace_lock)) == ops &&
 280	    rcu_dereference_protected(ops->next,
 281			lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
 282		*list = &ftrace_list_end;
 283		return 0;
 284	}
 285
 286	for (p = list; *p != &ftrace_list_end; p = &(*p)->next)
 287		if (*p == ops)
 288			break;
 289
 290	if (*p != ops)
 291		return -1;
 292
 293	*p = (*p)->next;
 294	return 0;
 295}
 296
 297static void ftrace_update_trampoline(struct ftrace_ops *ops);
 298
 299int __register_ftrace_function(struct ftrace_ops *ops)
 300{
 301	if (ops->flags & FTRACE_OPS_FL_DELETED)
 302		return -EINVAL;
 303
 304	if (WARN_ON(ops->flags & FTRACE_OPS_FL_ENABLED))
 305		return -EBUSY;
 306
 307#ifndef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 308	/*
 309	 * If the ftrace_ops specifies SAVE_REGS, then it only can be used
 310	 * if the arch supports it, or SAVE_REGS_IF_SUPPORTED is also set.
 311	 * Setting SAVE_REGS_IF_SUPPORTED makes SAVE_REGS irrelevant.
 312	 */
 313	if (ops->flags & FTRACE_OPS_FL_SAVE_REGS &&
 314	    !(ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED))
 315		return -EINVAL;
 316
 317	if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED)
 318		ops->flags |= FTRACE_OPS_FL_SAVE_REGS;
 319#endif
 320	if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT))
 321		return -EBUSY;
 322
 323	if (!is_kernel_core_data((unsigned long)ops))
 324		ops->flags |= FTRACE_OPS_FL_DYNAMIC;
 325
 326	add_ftrace_ops(&ftrace_ops_list, ops);
 327
 328	/* Always save the function, and reset at unregistering */
 329	ops->saved_func = ops->func;
 330
 331	if (ftrace_pids_enabled(ops))
 332		ops->func = ftrace_pid_func;
 333
 334	ftrace_update_trampoline(ops);
 335
 336	if (ftrace_enabled)
 337		update_ftrace_function();
 338
 339	return 0;
 340}
 341
 342int __unregister_ftrace_function(struct ftrace_ops *ops)
 343{
 344	int ret;
 345
 346	if (WARN_ON(!(ops->flags & FTRACE_OPS_FL_ENABLED)))
 347		return -EBUSY;
 348
 349	ret = remove_ftrace_ops(&ftrace_ops_list, ops);
 350
 351	if (ret < 0)
 352		return ret;
 353
 354	if (ftrace_enabled)
 355		update_ftrace_function();
 356
 357	ops->func = ops->saved_func;
 358
 359	return 0;
 360}
 361
 362static void ftrace_update_pid_func(void)
 363{
 364	struct ftrace_ops *op;
 365
 366	/* Only do something if we are tracing something */
 367	if (ftrace_trace_function == ftrace_stub)
 368		return;
 369
 370	do_for_each_ftrace_op(op, ftrace_ops_list) {
 371		if (op->flags & FTRACE_OPS_FL_PID) {
 372			op->func = ftrace_pids_enabled(op) ?
 373				ftrace_pid_func : op->saved_func;
 374			ftrace_update_trampoline(op);
 375		}
 376	} while_for_each_ftrace_op(op);
 377
 378	update_ftrace_function();
 379}
 380
 381#ifdef CONFIG_FUNCTION_PROFILER
 382struct ftrace_profile {
 383	struct hlist_node		node;
 384	unsigned long			ip;
 385	unsigned long			counter;
 386#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 387	unsigned long long		time;
 388	unsigned long long		time_squared;
 389#endif
 390};
 391
 392struct ftrace_profile_page {
 393	struct ftrace_profile_page	*next;
 394	unsigned long			index;
 395	struct ftrace_profile		records[];
 396};
 397
 398struct ftrace_profile_stat {
 399	atomic_t			disabled;
 400	struct hlist_head		*hash;
 401	struct ftrace_profile_page	*pages;
 402	struct ftrace_profile_page	*start;
 403	struct tracer_stat		stat;
 404};
 405
 406#define PROFILE_RECORDS_SIZE						\
 407	(PAGE_SIZE - offsetof(struct ftrace_profile_page, records))
 408
 409#define PROFILES_PER_PAGE					\
 410	(PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
 411
 412static int ftrace_profile_enabled __read_mostly;
 413
 414/* ftrace_profile_lock - synchronize the enable and disable of the profiler */
 415static DEFINE_MUTEX(ftrace_profile_lock);
 416
 417static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
 418
 419#define FTRACE_PROFILE_HASH_BITS 10
 420#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
 421
 422static void *
 423function_stat_next(void *v, int idx)
 424{
 425	struct ftrace_profile *rec = v;
 426	struct ftrace_profile_page *pg;
 427
 428	pg = (struct ftrace_profile_page *)((unsigned long)rec & PAGE_MASK);
 429
 430 again:
 431	if (idx != 0)
 432		rec++;
 433
 434	if ((void *)rec >= (void *)&pg->records[pg->index]) {
 435		pg = pg->next;
 436		if (!pg)
 437			return NULL;
 438		rec = &pg->records[0];
 439		if (!rec->counter)
 440			goto again;
 441	}
 442
 443	return rec;
 444}
 445
 446static void *function_stat_start(struct tracer_stat *trace)
 447{
 448	struct ftrace_profile_stat *stat =
 449		container_of(trace, struct ftrace_profile_stat, stat);
 450
 451	if (!stat || !stat->start)
 452		return NULL;
 453
 454	return function_stat_next(&stat->start->records[0], 0);
 455}
 456
 457#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 458/* function graph compares on total time */
 459static int function_stat_cmp(const void *p1, const void *p2)
 460{
 461	const struct ftrace_profile *a = p1;
 462	const struct ftrace_profile *b = p2;
 463
 464	if (a->time < b->time)
 465		return -1;
 466	if (a->time > b->time)
 467		return 1;
 468	else
 469		return 0;
 470}
 471#else
 472/* not function graph compares against hits */
 473static int function_stat_cmp(const void *p1, const void *p2)
 474{
 475	const struct ftrace_profile *a = p1;
 476	const struct ftrace_profile *b = p2;
 477
 478	if (a->counter < b->counter)
 479		return -1;
 480	if (a->counter > b->counter)
 481		return 1;
 482	else
 483		return 0;
 484}
 485#endif
 486
 487static int function_stat_headers(struct seq_file *m)
 488{
 489#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 490	seq_puts(m, "  Function                               "
 491		 "Hit    Time            Avg             s^2\n"
 492		    "  --------                               "
 493		 "---    ----            ---             ---\n");
 494#else
 495	seq_puts(m, "  Function                               Hit\n"
 496		    "  --------                               ---\n");
 497#endif
 498	return 0;
 499}
 500
 501static int function_stat_show(struct seq_file *m, void *v)
 502{
 503	struct ftrace_profile *rec = v;
 504	char str[KSYM_SYMBOL_LEN];
 505	int ret = 0;
 506#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 507	static struct trace_seq s;
 508	unsigned long long avg;
 509	unsigned long long stddev;
 510#endif
 511	mutex_lock(&ftrace_profile_lock);
 512
 513	/* we raced with function_profile_reset() */
 514	if (unlikely(rec->counter == 0)) {
 515		ret = -EBUSY;
 516		goto out;
 517	}
 518
 519#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 520	avg = div64_ul(rec->time, rec->counter);
 521	if (tracing_thresh && (avg < tracing_thresh))
 522		goto out;
 523#endif
 524
 525	kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
 526	seq_printf(m, "  %-30.30s  %10lu", str, rec->counter);
 527
 528#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 529	seq_puts(m, "    ");
 530
 531	/* Sample standard deviation (s^2) */
 532	if (rec->counter <= 1)
 533		stddev = 0;
 534	else {
 535		/*
 536		 * Apply Welford's method:
 537		 * s^2 = 1 / (n * (n-1)) * (n * \Sum (x_i)^2 - (\Sum x_i)^2)
 538		 */
 539		stddev = rec->counter * rec->time_squared -
 540			 rec->time * rec->time;
 541
 542		/*
 543		 * Divide only 1000 for ns^2 -> us^2 conversion.
 544		 * trace_print_graph_duration will divide 1000 again.
 545		 */
 546		stddev = div64_ul(stddev,
 547				  rec->counter * (rec->counter - 1) * 1000);
 548	}
 549
 550	trace_seq_init(&s);
 551	trace_print_graph_duration(rec->time, &s);
 552	trace_seq_puts(&s, "    ");
 553	trace_print_graph_duration(avg, &s);
 554	trace_seq_puts(&s, "    ");
 555	trace_print_graph_duration(stddev, &s);
 556	trace_print_seq(m, &s);
 557#endif
 558	seq_putc(m, '\n');
 559out:
 560	mutex_unlock(&ftrace_profile_lock);
 561
 562	return ret;
 563}
 564
 565static void ftrace_profile_reset(struct ftrace_profile_stat *stat)
 566{
 567	struct ftrace_profile_page *pg;
 568
 569	pg = stat->pages = stat->start;
 570
 571	while (pg) {
 572		memset(pg->records, 0, PROFILE_RECORDS_SIZE);
 573		pg->index = 0;
 574		pg = pg->next;
 575	}
 576
 577	memset(stat->hash, 0,
 578	       FTRACE_PROFILE_HASH_SIZE * sizeof(struct hlist_head));
 579}
 580
 581static int ftrace_profile_pages_init(struct ftrace_profile_stat *stat)
 582{
 583	struct ftrace_profile_page *pg;
 584	int functions;
 585	int pages;
 586	int i;
 587
 588	/* If we already allocated, do nothing */
 589	if (stat->pages)
 590		return 0;
 591
 592	stat->pages = (void *)get_zeroed_page(GFP_KERNEL);
 593	if (!stat->pages)
 594		return -ENOMEM;
 595
 596#ifdef CONFIG_DYNAMIC_FTRACE
 597	functions = ftrace_update_tot_cnt;
 598#else
 599	/*
 600	 * We do not know the number of functions that exist because
 601	 * dynamic tracing is what counts them. With past experience
 602	 * we have around 20K functions. That should be more than enough.
 603	 * It is highly unlikely we will execute every function in
 604	 * the kernel.
 605	 */
 606	functions = 20000;
 607#endif
 608
 609	pg = stat->start = stat->pages;
 610
 611	pages = DIV_ROUND_UP(functions, PROFILES_PER_PAGE);
 612
 613	for (i = 1; i < pages; i++) {
 614		pg->next = (void *)get_zeroed_page(GFP_KERNEL);
 615		if (!pg->next)
 616			goto out_free;
 617		pg = pg->next;
 618	}
 619
 620	return 0;
 621
 622 out_free:
 623	pg = stat->start;
 624	while (pg) {
 625		unsigned long tmp = (unsigned long)pg;
 626
 627		pg = pg->next;
 628		free_page(tmp);
 629	}
 630
 631	stat->pages = NULL;
 632	stat->start = NULL;
 633
 634	return -ENOMEM;
 635}
 636
 637static int ftrace_profile_init_cpu(int cpu)
 638{
 639	struct ftrace_profile_stat *stat;
 640	int size;
 641
 642	stat = &per_cpu(ftrace_profile_stats, cpu);
 643
 644	if (stat->hash) {
 645		/* If the profile is already created, simply reset it */
 646		ftrace_profile_reset(stat);
 647		return 0;
 648	}
 649
 650	/*
 651	 * We are profiling all functions, but usually only a few thousand
 652	 * functions are hit. We'll make a hash of 1024 items.
 653	 */
 654	size = FTRACE_PROFILE_HASH_SIZE;
 655
 656	stat->hash = kcalloc(size, sizeof(struct hlist_head), GFP_KERNEL);
 657
 658	if (!stat->hash)
 659		return -ENOMEM;
 660
 661	/* Preallocate the function profiling pages */
 662	if (ftrace_profile_pages_init(stat) < 0) {
 663		kfree(stat->hash);
 664		stat->hash = NULL;
 665		return -ENOMEM;
 666	}
 667
 668	return 0;
 669}
 670
 671static int ftrace_profile_init(void)
 672{
 673	int cpu;
 674	int ret = 0;
 675
 676	for_each_possible_cpu(cpu) {
 677		ret = ftrace_profile_init_cpu(cpu);
 678		if (ret)
 679			break;
 680	}
 681
 682	return ret;
 683}
 684
 685/* interrupts must be disabled */
 686static struct ftrace_profile *
 687ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
 688{
 689	struct ftrace_profile *rec;
 690	struct hlist_head *hhd;
 691	unsigned long key;
 692
 693	key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
 694	hhd = &stat->hash[key];
 695
 696	if (hlist_empty(hhd))
 697		return NULL;
 698
 699	hlist_for_each_entry_rcu_notrace(rec, hhd, node) {
 700		if (rec->ip == ip)
 701			return rec;
 702	}
 703
 704	return NULL;
 705}
 706
 707static void ftrace_add_profile(struct ftrace_profile_stat *stat,
 708			       struct ftrace_profile *rec)
 709{
 710	unsigned long key;
 711
 712	key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
 713	hlist_add_head_rcu(&rec->node, &stat->hash[key]);
 714}
 715
 716/*
 717 * The memory is already allocated, this simply finds a new record to use.
 718 */
 719static struct ftrace_profile *
 720ftrace_profile_alloc(struct ftrace_profile_stat *stat, unsigned long ip)
 721{
 722	struct ftrace_profile *rec = NULL;
 723
 724	/* prevent recursion (from NMIs) */
 725	if (atomic_inc_return(&stat->disabled) != 1)
 726		goto out;
 727
 728	/*
 729	 * Try to find the function again since an NMI
 730	 * could have added it
 731	 */
 732	rec = ftrace_find_profiled_func(stat, ip);
 733	if (rec)
 734		goto out;
 735
 736	if (stat->pages->index == PROFILES_PER_PAGE) {
 737		if (!stat->pages->next)
 738			goto out;
 739		stat->pages = stat->pages->next;
 740	}
 741
 742	rec = &stat->pages->records[stat->pages->index++];
 743	rec->ip = ip;
 744	ftrace_add_profile(stat, rec);
 745
 746 out:
 747	atomic_dec(&stat->disabled);
 748
 749	return rec;
 750}
 751
 752static void
 753function_profile_call(unsigned long ip, unsigned long parent_ip,
 754		      struct ftrace_ops *ops, struct ftrace_regs *fregs)
 755{
 756	struct ftrace_profile_stat *stat;
 757	struct ftrace_profile *rec;
 758	unsigned long flags;
 759
 760	if (!ftrace_profile_enabled)
 761		return;
 762
 763	local_irq_save(flags);
 764
 765	stat = this_cpu_ptr(&ftrace_profile_stats);
 766	if (!stat->hash || !ftrace_profile_enabled)
 767		goto out;
 768
 769	rec = ftrace_find_profiled_func(stat, ip);
 770	if (!rec) {
 771		rec = ftrace_profile_alloc(stat, ip);
 772		if (!rec)
 773			goto out;
 774	}
 775
 776	rec->counter++;
 777 out:
 778	local_irq_restore(flags);
 779}
 780
 781#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 782static bool fgraph_graph_time = true;
 783
 784void ftrace_graph_graph_time_control(bool enable)
 785{
 786	fgraph_graph_time = enable;
 787}
 788
 789static int profile_graph_entry(struct ftrace_graph_ent *trace)
 790{
 791	struct ftrace_ret_stack *ret_stack;
 792
 793	function_profile_call(trace->func, 0, NULL, NULL);
 794
 795	/* If function graph is shutting down, ret_stack can be NULL */
 796	if (!current->ret_stack)
 797		return 0;
 798
 799	ret_stack = ftrace_graph_get_ret_stack(current, 0);
 800	if (ret_stack)
 801		ret_stack->subtime = 0;
 802
 803	return 1;
 804}
 805
 806static void profile_graph_return(struct ftrace_graph_ret *trace)
 807{
 808	struct ftrace_ret_stack *ret_stack;
 809	struct ftrace_profile_stat *stat;
 810	unsigned long long calltime;
 811	struct ftrace_profile *rec;
 812	unsigned long flags;
 813
 814	local_irq_save(flags);
 815	stat = this_cpu_ptr(&ftrace_profile_stats);
 816	if (!stat->hash || !ftrace_profile_enabled)
 817		goto out;
 818
 819	/* If the calltime was zero'd ignore it */
 820	if (!trace->calltime)
 821		goto out;
 822
 823	calltime = trace->rettime - trace->calltime;
 824
 825	if (!fgraph_graph_time) {
 826
 827		/* Append this call time to the parent time to subtract */
 828		ret_stack = ftrace_graph_get_ret_stack(current, 1);
 829		if (ret_stack)
 830			ret_stack->subtime += calltime;
 831
 832		ret_stack = ftrace_graph_get_ret_stack(current, 0);
 833		if (ret_stack && ret_stack->subtime < calltime)
 834			calltime -= ret_stack->subtime;
 835		else
 836			calltime = 0;
 837	}
 838
 839	rec = ftrace_find_profiled_func(stat, trace->func);
 840	if (rec) {
 841		rec->time += calltime;
 842		rec->time_squared += calltime * calltime;
 843	}
 844
 845 out:
 846	local_irq_restore(flags);
 847}
 848
 849static struct fgraph_ops fprofiler_ops = {
 850	.entryfunc = &profile_graph_entry,
 851	.retfunc = &profile_graph_return,
 852};
 853
 854static int register_ftrace_profiler(void)
 855{
 856	return register_ftrace_graph(&fprofiler_ops);
 857}
 858
 859static void unregister_ftrace_profiler(void)
 860{
 861	unregister_ftrace_graph(&fprofiler_ops);
 862}
 863#else
 864static struct ftrace_ops ftrace_profile_ops __read_mostly = {
 865	.func		= function_profile_call,
 866	.flags		= FTRACE_OPS_FL_INITIALIZED,
 867	INIT_OPS_HASH(ftrace_profile_ops)
 868};
 869
 870static int register_ftrace_profiler(void)
 871{
 872	return register_ftrace_function(&ftrace_profile_ops);
 873}
 874
 875static void unregister_ftrace_profiler(void)
 876{
 877	unregister_ftrace_function(&ftrace_profile_ops);
 878}
 879#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 880
 881static ssize_t
 882ftrace_profile_write(struct file *filp, const char __user *ubuf,
 883		     size_t cnt, loff_t *ppos)
 884{
 885	unsigned long val;
 886	int ret;
 887
 888	ret = kstrtoul_from_user(ubuf, cnt, 10, &val);
 889	if (ret)
 890		return ret;
 891
 892	val = !!val;
 893
 894	mutex_lock(&ftrace_profile_lock);
 895	if (ftrace_profile_enabled ^ val) {
 896		if (val) {
 897			ret = ftrace_profile_init();
 898			if (ret < 0) {
 899				cnt = ret;
 900				goto out;
 901			}
 902
 903			ret = register_ftrace_profiler();
 904			if (ret < 0) {
 905				cnt = ret;
 906				goto out;
 907			}
 908			ftrace_profile_enabled = 1;
 909		} else {
 910			ftrace_profile_enabled = 0;
 911			/*
 912			 * unregister_ftrace_profiler calls stop_machine
 913			 * so this acts like an synchronize_rcu.
 914			 */
 915			unregister_ftrace_profiler();
 916		}
 917	}
 918 out:
 919	mutex_unlock(&ftrace_profile_lock);
 920
 921	*ppos += cnt;
 922
 923	return cnt;
 924}
 925
 926static ssize_t
 927ftrace_profile_read(struct file *filp, char __user *ubuf,
 928		     size_t cnt, loff_t *ppos)
 929{
 930	char buf[64];		/* big enough to hold a number */
 931	int r;
 932
 933	r = sprintf(buf, "%u\n", ftrace_profile_enabled);
 934	return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
 935}
 936
 937static const struct file_operations ftrace_profile_fops = {
 938	.open		= tracing_open_generic,
 939	.read		= ftrace_profile_read,
 940	.write		= ftrace_profile_write,
 941	.llseek		= default_llseek,
 942};
 943
 944/* used to initialize the real stat files */
 945static struct tracer_stat function_stats __initdata = {
 946	.name		= "functions",
 947	.stat_start	= function_stat_start,
 948	.stat_next	= function_stat_next,
 949	.stat_cmp	= function_stat_cmp,
 950	.stat_headers	= function_stat_headers,
 951	.stat_show	= function_stat_show
 952};
 953
 954static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
 955{
 956	struct ftrace_profile_stat *stat;
 
 957	char *name;
 958	int ret;
 959	int cpu;
 960
 961	for_each_possible_cpu(cpu) {
 962		stat = &per_cpu(ftrace_profile_stats, cpu);
 963
 964		name = kasprintf(GFP_KERNEL, "function%d", cpu);
 965		if (!name) {
 966			/*
 967			 * The files created are permanent, if something happens
 968			 * we still do not free memory.
 969			 */
 970			WARN(1,
 971			     "Could not allocate stat file for cpu %d\n",
 972			     cpu);
 973			return;
 974		}
 975		stat->stat = function_stats;
 976		stat->stat.name = name;
 977		ret = register_stat_tracer(&stat->stat);
 978		if (ret) {
 979			WARN(1,
 980			     "Could not register function stat for cpu %d\n",
 981			     cpu);
 982			kfree(name);
 983			return;
 984		}
 985	}
 986
 987	trace_create_file("function_profile_enabled",
 988			  TRACE_MODE_WRITE, d_tracer, NULL,
 989			  &ftrace_profile_fops);
 
 990}
 991
 992#else /* CONFIG_FUNCTION_PROFILER */
 993static __init void ftrace_profile_tracefs(struct dentry *d_tracer)
 994{
 995}
 996#endif /* CONFIG_FUNCTION_PROFILER */
 997
 998#ifdef CONFIG_DYNAMIC_FTRACE
 999
1000static struct ftrace_ops *removed_ops;
1001
1002/*
1003 * Set when doing a global update, like enabling all recs or disabling them.
1004 * It is not set when just updating a single ftrace_ops.
1005 */
1006static bool update_all_ops;
1007
1008#ifndef CONFIG_FTRACE_MCOUNT_RECORD
1009# error Dynamic ftrace depends on MCOUNT_RECORD
1010#endif
1011
1012struct ftrace_func_probe {
1013	struct ftrace_probe_ops	*probe_ops;
1014	struct ftrace_ops	ops;
1015	struct trace_array	*tr;
1016	struct list_head	list;
1017	void			*data;
1018	int			ref;
1019};
1020
1021/*
1022 * We make these constant because no one should touch them,
1023 * but they are used as the default "empty hash", to avoid allocating
1024 * it all the time. These are in a read only section such that if
1025 * anyone does try to modify it, it will cause an exception.
1026 */
1027static const struct hlist_head empty_buckets[1];
1028static const struct ftrace_hash empty_hash = {
1029	.buckets = (struct hlist_head *)empty_buckets,
1030};
1031#define EMPTY_HASH	((struct ftrace_hash *)&empty_hash)
1032
1033struct ftrace_ops global_ops = {
1034	.func				= ftrace_stub,
1035	.local_hash.notrace_hash	= EMPTY_HASH,
1036	.local_hash.filter_hash		= EMPTY_HASH,
1037	INIT_OPS_HASH(global_ops)
1038	.flags				= FTRACE_OPS_FL_INITIALIZED |
 
1039					  FTRACE_OPS_FL_PID,
1040};
1041
1042/*
1043 * Used by the stack unwinder to know about dynamic ftrace trampolines.
1044 */
1045struct ftrace_ops *ftrace_ops_trampoline(unsigned long addr)
1046{
1047	struct ftrace_ops *op = NULL;
1048
1049	/*
1050	 * Some of the ops may be dynamically allocated,
1051	 * they are freed after a synchronize_rcu().
1052	 */
1053	preempt_disable_notrace();
1054
1055	do_for_each_ftrace_op(op, ftrace_ops_list) {
1056		/*
1057		 * This is to check for dynamically allocated trampolines.
1058		 * Trampolines that are in kernel text will have
1059		 * core_kernel_text() return true.
1060		 */
1061		if (op->trampoline && op->trampoline_size)
1062			if (addr >= op->trampoline &&
1063			    addr < op->trampoline + op->trampoline_size) {
1064				preempt_enable_notrace();
1065				return op;
1066			}
1067	} while_for_each_ftrace_op(op);
1068	preempt_enable_notrace();
1069
1070	return NULL;
1071}
1072
1073/*
1074 * This is used by __kernel_text_address() to return true if the
1075 * address is on a dynamically allocated trampoline that would
1076 * not return true for either core_kernel_text() or
1077 * is_module_text_address().
1078 */
1079bool is_ftrace_trampoline(unsigned long addr)
1080{
1081	return ftrace_ops_trampoline(addr) != NULL;
1082}
1083
1084struct ftrace_page {
1085	struct ftrace_page	*next;
1086	struct dyn_ftrace	*records;
1087	int			index;
1088	int			order;
1089};
1090
1091#define ENTRY_SIZE sizeof(struct dyn_ftrace)
1092#define ENTRIES_PER_PAGE (PAGE_SIZE / ENTRY_SIZE)
1093
1094static struct ftrace_page	*ftrace_pages_start;
1095static struct ftrace_page	*ftrace_pages;
1096
1097static __always_inline unsigned long
1098ftrace_hash_key(struct ftrace_hash *hash, unsigned long ip)
1099{
1100	if (hash->size_bits > 0)
1101		return hash_long(ip, hash->size_bits);
1102
1103	return 0;
1104}
1105
1106/* Only use this function if ftrace_hash_empty() has already been tested */
1107static __always_inline struct ftrace_func_entry *
1108__ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1109{
1110	unsigned long key;
1111	struct ftrace_func_entry *entry;
1112	struct hlist_head *hhd;
1113
1114	key = ftrace_hash_key(hash, ip);
1115	hhd = &hash->buckets[key];
1116
1117	hlist_for_each_entry_rcu_notrace(entry, hhd, hlist) {
1118		if (entry->ip == ip)
1119			return entry;
1120	}
1121	return NULL;
1122}
1123
1124/**
1125 * ftrace_lookup_ip - Test to see if an ip exists in an ftrace_hash
1126 * @hash: The hash to look at
1127 * @ip: The instruction pointer to test
1128 *
1129 * Search a given @hash to see if a given instruction pointer (@ip)
1130 * exists in it.
1131 *
1132 * Returns the entry that holds the @ip if found. NULL otherwise.
1133 */
1134struct ftrace_func_entry *
1135ftrace_lookup_ip(struct ftrace_hash *hash, unsigned long ip)
1136{
1137	if (ftrace_hash_empty(hash))
1138		return NULL;
1139
1140	return __ftrace_lookup_ip(hash, ip);
1141}
1142
1143static void __add_hash_entry(struct ftrace_hash *hash,
1144			     struct ftrace_func_entry *entry)
1145{
1146	struct hlist_head *hhd;
1147	unsigned long key;
1148
1149	key = ftrace_hash_key(hash, entry->ip);
1150	hhd = &hash->buckets[key];
1151	hlist_add_head(&entry->hlist, hhd);
1152	hash->count++;
1153}
1154
1155static int add_hash_entry(struct ftrace_hash *hash, unsigned long ip)
1156{
1157	struct ftrace_func_entry *entry;
1158
1159	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
1160	if (!entry)
1161		return -ENOMEM;
1162
1163	entry->ip = ip;
1164	__add_hash_entry(hash, entry);
1165
1166	return 0;
1167}
1168
1169static void
1170free_hash_entry(struct ftrace_hash *hash,
1171		  struct ftrace_func_entry *entry)
1172{
1173	hlist_del(&entry->hlist);
1174	kfree(entry);
1175	hash->count--;
1176}
1177
1178static void
1179remove_hash_entry(struct ftrace_hash *hash,
1180		  struct ftrace_func_entry *entry)
1181{
1182	hlist_del_rcu(&entry->hlist);
1183	hash->count--;
1184}
1185
1186static void ftrace_hash_clear(struct ftrace_hash *hash)
1187{
1188	struct hlist_head *hhd;
1189	struct hlist_node *tn;
1190	struct ftrace_func_entry *entry;
1191	int size = 1 << hash->size_bits;
1192	int i;
1193
1194	if (!hash->count)
1195		return;
1196
1197	for (i = 0; i < size; i++) {
1198		hhd = &hash->buckets[i];
1199		hlist_for_each_entry_safe(entry, tn, hhd, hlist)
1200			free_hash_entry(hash, entry);
1201	}
1202	FTRACE_WARN_ON(hash->count);
1203}
1204
1205static void free_ftrace_mod(struct ftrace_mod_load *ftrace_mod)
1206{
1207	list_del(&ftrace_mod->list);
1208	kfree(ftrace_mod->module);
1209	kfree(ftrace_mod->func);
1210	kfree(ftrace_mod);
1211}
1212
1213static void clear_ftrace_mod_list(struct list_head *head)
1214{
1215	struct ftrace_mod_load *p, *n;
1216
1217	/* stack tracer isn't supported yet */
1218	if (!head)
1219		return;
1220
1221	mutex_lock(&ftrace_lock);
1222	list_for_each_entry_safe(p, n, head, list)
1223		free_ftrace_mod(p);
1224	mutex_unlock(&ftrace_lock);
1225}
1226
1227static void free_ftrace_hash(struct ftrace_hash *hash)
1228{
1229	if (!hash || hash == EMPTY_HASH)
1230		return;
1231	ftrace_hash_clear(hash);
1232	kfree(hash->buckets);
1233	kfree(hash);
1234}
1235
1236static void __free_ftrace_hash_rcu(struct rcu_head *rcu)
1237{
1238	struct ftrace_hash *hash;
1239
1240	hash = container_of(rcu, struct ftrace_hash, rcu);
1241	free_ftrace_hash(hash);
1242}
1243
1244static void free_ftrace_hash_rcu(struct ftrace_hash *hash)
1245{
1246	if (!hash || hash == EMPTY_HASH)
1247		return;
1248	call_rcu(&hash->rcu, __free_ftrace_hash_rcu);
1249}
1250
1251/**
1252 * ftrace_free_filter - remove all filters for an ftrace_ops
1253 * @ops - the ops to remove the filters from
1254 */
1255void ftrace_free_filter(struct ftrace_ops *ops)
1256{
1257	ftrace_ops_init(ops);
1258	free_ftrace_hash(ops->func_hash->filter_hash);
1259	free_ftrace_hash(ops->func_hash->notrace_hash);
1260}
1261EXPORT_SYMBOL_GPL(ftrace_free_filter);
1262
1263static struct ftrace_hash *alloc_ftrace_hash(int size_bits)
1264{
1265	struct ftrace_hash *hash;
1266	int size;
1267
1268	hash = kzalloc(sizeof(*hash), GFP_KERNEL);
1269	if (!hash)
1270		return NULL;
1271
1272	size = 1 << size_bits;
1273	hash->buckets = kcalloc(size, sizeof(*hash->buckets), GFP_KERNEL);
1274
1275	if (!hash->buckets) {
1276		kfree(hash);
1277		return NULL;
1278	}
1279
1280	hash->size_bits = size_bits;
1281
1282	return hash;
1283}
1284
1285
1286static int ftrace_add_mod(struct trace_array *tr,
1287			  const char *func, const char *module,
1288			  int enable)
1289{
1290	struct ftrace_mod_load *ftrace_mod;
1291	struct list_head *mod_head = enable ? &tr->mod_trace : &tr->mod_notrace;
1292
1293	ftrace_mod = kzalloc(sizeof(*ftrace_mod), GFP_KERNEL);
1294	if (!ftrace_mod)
1295		return -ENOMEM;
1296
1297	INIT_LIST_HEAD(&ftrace_mod->list);
1298	ftrace_mod->func = kstrdup(func, GFP_KERNEL);
1299	ftrace_mod->module = kstrdup(module, GFP_KERNEL);
1300	ftrace_mod->enable = enable;
1301
1302	if (!ftrace_mod->func || !ftrace_mod->module)
1303		goto out_free;
1304
1305	list_add(&ftrace_mod->list, mod_head);
1306
1307	return 0;
1308
1309 out_free:
1310	free_ftrace_mod(ftrace_mod);
1311
1312	return -ENOMEM;
1313}
1314
1315static struct ftrace_hash *
1316alloc_and_copy_ftrace_hash(int size_bits, struct ftrace_hash *hash)
1317{
1318	struct ftrace_func_entry *entry;
1319	struct ftrace_hash *new_hash;
1320	int size;
1321	int ret;
1322	int i;
1323
1324	new_hash = alloc_ftrace_hash(size_bits);
1325	if (!new_hash)
1326		return NULL;
1327
1328	if (hash)
1329		new_hash->flags = hash->flags;
1330
1331	/* Empty hash? */
1332	if (ftrace_hash_empty(hash))
1333		return new_hash;
1334
1335	size = 1 << hash->size_bits;
1336	for (i = 0; i < size; i++) {
1337		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
1338			ret = add_hash_entry(new_hash, entry->ip);
1339			if (ret < 0)
1340				goto free_hash;
1341		}
1342	}
1343
1344	FTRACE_WARN_ON(new_hash->count != hash->count);
1345
1346	return new_hash;
1347
1348 free_hash:
1349	free_ftrace_hash(new_hash);
1350	return NULL;
1351}
1352
1353static void
1354ftrace_hash_rec_disable_modify(struct ftrace_ops *ops, int filter_hash);
1355static void
1356ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash);
1357
1358static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
1359				       struct ftrace_hash *new_hash);
1360
1361static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size)
1362{
1363	struct ftrace_func_entry *entry;
1364	struct ftrace_hash *new_hash;
1365	struct hlist_head *hhd;
1366	struct hlist_node *tn;
1367	int bits = 0;
1368	int i;
1369
1370	/*
1371	 * Use around half the size (max bit of it), but
1372	 * a minimum of 2 is fine (as size of 0 or 1 both give 1 for bits).
1373	 */
1374	bits = fls(size / 2);
 
1375
1376	/* Don't allocate too much */
1377	if (bits > FTRACE_HASH_MAX_BITS)
1378		bits = FTRACE_HASH_MAX_BITS;
1379
1380	new_hash = alloc_ftrace_hash(bits);
1381	if (!new_hash)
1382		return NULL;
1383
1384	new_hash->flags = src->flags;
1385
1386	size = 1 << src->size_bits;
1387	for (i = 0; i < size; i++) {
1388		hhd = &src->buckets[i];
1389		hlist_for_each_entry_safe(entry, tn, hhd, hlist) {
1390			remove_hash_entry(src, entry);
1391			__add_hash_entry(new_hash, entry);
1392		}
1393	}
1394	return new_hash;
1395}
1396
1397static struct ftrace_hash *
1398__ftrace_hash_move(struct ftrace_hash *src)
1399{
1400	int size = src->count;
1401
1402	/*
1403	 * If the new source is empty, just return the empty_hash.
1404	 */
1405	if (ftrace_hash_empty(src))
1406		return EMPTY_HASH;
1407
1408	return dup_hash(src, size);
1409}
1410
1411static int
1412ftrace_hash_move(struct ftrace_ops *ops, int enable,
1413		 struct ftrace_hash **dst, struct ftrace_hash *src)
1414{
1415	struct ftrace_hash *new_hash;
1416	int ret;
1417
1418	/* Reject setting notrace hash on IPMODIFY ftrace_ops */
1419	if (ops->flags & FTRACE_OPS_FL_IPMODIFY && !enable)
1420		return -EINVAL;
1421
1422	new_hash = __ftrace_hash_move(src);
1423	if (!new_hash)
1424		return -ENOMEM;
1425
1426	/* Make sure this can be applied if it is IPMODIFY ftrace_ops */
1427	if (enable) {
1428		/* IPMODIFY should be updated only when filter_hash updating */
1429		ret = ftrace_hash_ipmodify_update(ops, new_hash);
1430		if (ret < 0) {
1431			free_ftrace_hash(new_hash);
1432			return ret;
1433		}
1434	}
1435
1436	/*
1437	 * Remove the current set, update the hash and add
1438	 * them back.
1439	 */
1440	ftrace_hash_rec_disable_modify(ops, enable);
1441
1442	rcu_assign_pointer(*dst, new_hash);
1443
1444	ftrace_hash_rec_enable_modify(ops, enable);
1445
1446	return 0;
1447}
1448
1449static bool hash_contains_ip(unsigned long ip,
1450			     struct ftrace_ops_hash *hash)
1451{
1452	/*
1453	 * The function record is a match if it exists in the filter
1454	 * hash and not in the notrace hash. Note, an empty hash is
1455	 * considered a match for the filter hash, but an empty
1456	 * notrace hash is considered not in the notrace hash.
1457	 */
1458	return (ftrace_hash_empty(hash->filter_hash) ||
1459		__ftrace_lookup_ip(hash->filter_hash, ip)) &&
1460		(ftrace_hash_empty(hash->notrace_hash) ||
1461		 !__ftrace_lookup_ip(hash->notrace_hash, ip));
1462}
1463
1464/*
1465 * Test the hashes for this ops to see if we want to call
1466 * the ops->func or not.
1467 *
1468 * It's a match if the ip is in the ops->filter_hash or
1469 * the filter_hash does not exist or is empty,
1470 *  AND
1471 * the ip is not in the ops->notrace_hash.
1472 *
1473 * This needs to be called with preemption disabled as
1474 * the hashes are freed with call_rcu().
1475 */
1476int
1477ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
1478{
1479	struct ftrace_ops_hash hash;
1480	int ret;
1481
1482#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
1483	/*
1484	 * There's a small race when adding ops that the ftrace handler
1485	 * that wants regs, may be called without them. We can not
1486	 * allow that handler to be called if regs is NULL.
1487	 */
1488	if (regs == NULL && (ops->flags & FTRACE_OPS_FL_SAVE_REGS))
1489		return 0;
1490#endif
1491
1492	rcu_assign_pointer(hash.filter_hash, ops->func_hash->filter_hash);
1493	rcu_assign_pointer(hash.notrace_hash, ops->func_hash->notrace_hash);
1494
1495	if (hash_contains_ip(ip, &hash))
1496		ret = 1;
1497	else
1498		ret = 0;
1499
1500	return ret;
1501}
1502
1503/*
1504 * This is a double for. Do not use 'break' to break out of the loop,
1505 * you must use a goto.
1506 */
1507#define do_for_each_ftrace_rec(pg, rec)					\
1508	for (pg = ftrace_pages_start; pg; pg = pg->next) {		\
1509		int _____i;						\
1510		for (_____i = 0; _____i < pg->index; _____i++) {	\
1511			rec = &pg->records[_____i];
1512
1513#define while_for_each_ftrace_rec()		\
1514		}				\
1515	}
1516
1517
1518static int ftrace_cmp_recs(const void *a, const void *b)
1519{
1520	const struct dyn_ftrace *key = a;
1521	const struct dyn_ftrace *rec = b;
1522
1523	if (key->flags < rec->ip)
1524		return -1;
1525	if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
1526		return 1;
1527	return 0;
1528}
1529
1530static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
1531{
1532	struct ftrace_page *pg;
1533	struct dyn_ftrace *rec = NULL;
1534	struct dyn_ftrace key;
1535
1536	key.ip = start;
1537	key.flags = end;	/* overload flags, as it is unsigned long */
1538
1539	for (pg = ftrace_pages_start; pg; pg = pg->next) {
1540		if (end < pg->records[0].ip ||
1541		    start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
1542			continue;
1543		rec = bsearch(&key, pg->records, pg->index,
1544			      sizeof(struct dyn_ftrace),
1545			      ftrace_cmp_recs);
1546		if (rec)
1547			break;
1548	}
1549	return rec;
1550}
1551
1552/**
1553 * ftrace_location_range - return the first address of a traced location
1554 *	if it touches the given ip range
1555 * @start: start of range to search.
1556 * @end: end of range to search (inclusive). @end points to the last byte
1557 *	to check.
1558 *
1559 * Returns rec->ip if the related ftrace location is a least partly within
1560 * the given address range. That is, the first address of the instruction
1561 * that is either a NOP or call to the function tracer. It checks the ftrace
1562 * internal tables to determine if the address belongs or not.
1563 */
1564unsigned long ftrace_location_range(unsigned long start, unsigned long end)
1565{
1566	struct dyn_ftrace *rec;
1567
1568	rec = lookup_rec(start, end);
1569	if (rec)
1570		return rec->ip;
1571
1572	return 0;
1573}
1574
1575/**
1576 * ftrace_location - return the ftrace location
1577 * @ip: the instruction pointer to check
1578 *
1579 * If @ip matches the ftrace location, return @ip.
1580 * If @ip matches sym+0, return sym's ftrace location.
1581 * Otherwise, return 0.
 
1582 */
1583unsigned long ftrace_location(unsigned long ip)
1584{
1585	struct dyn_ftrace *rec;
1586	unsigned long offset;
1587	unsigned long size;
1588
1589	rec = lookup_rec(ip, ip);
1590	if (!rec) {
1591		if (!kallsyms_lookup_size_offset(ip, &size, &offset))
1592			goto out;
1593
1594		/* map sym+0 to __fentry__ */
1595		if (!offset)
1596			rec = lookup_rec(ip, ip + size - 1);
1597	}
1598
1599	if (rec)
1600		return rec->ip;
1601
1602out:
1603	return 0;
1604}
1605
1606/**
1607 * ftrace_text_reserved - return true if range contains an ftrace location
1608 * @start: start of range to search
1609 * @end: end of range to search (inclusive). @end points to the last byte to check.
1610 *
1611 * Returns 1 if @start and @end contains a ftrace location.
1612 * That is, the instruction that is either a NOP or call to
1613 * the function tracer. It checks the ftrace internal tables to
1614 * determine if the address belongs or not.
1615 */
1616int ftrace_text_reserved(const void *start, const void *end)
1617{
1618	unsigned long ret;
1619
1620	ret = ftrace_location_range((unsigned long)start,
1621				    (unsigned long)end);
1622
1623	return (int)!!ret;
1624}
1625
1626/* Test if ops registered to this rec needs regs */
1627static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec)
1628{
1629	struct ftrace_ops *ops;
1630	bool keep_regs = false;
1631
1632	for (ops = ftrace_ops_list;
1633	     ops != &ftrace_list_end; ops = ops->next) {
1634		/* pass rec in as regs to have non-NULL val */
1635		if (ftrace_ops_test(ops, rec->ip, rec)) {
1636			if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1637				keep_regs = true;
1638				break;
1639			}
1640		}
1641	}
1642
1643	return  keep_regs;
1644}
1645
1646static struct ftrace_ops *
1647ftrace_find_tramp_ops_any(struct dyn_ftrace *rec);
1648static struct ftrace_ops *
1649ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude);
1650static struct ftrace_ops *
1651ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, struct ftrace_ops *ops);
1652
1653static bool skip_record(struct dyn_ftrace *rec)
1654{
1655	/*
1656	 * At boot up, weak functions are set to disable. Function tracing
1657	 * can be enabled before they are, and they still need to be disabled now.
1658	 * If the record is disabled, still continue if it is marked as already
1659	 * enabled (this is needed to keep the accounting working).
1660	 */
1661	return rec->flags & FTRACE_FL_DISABLED &&
1662		!(rec->flags & FTRACE_FL_ENABLED);
1663}
1664
1665static bool __ftrace_hash_rec_update(struct ftrace_ops *ops,
1666				     int filter_hash,
1667				     bool inc)
1668{
1669	struct ftrace_hash *hash;
1670	struct ftrace_hash *other_hash;
1671	struct ftrace_page *pg;
1672	struct dyn_ftrace *rec;
1673	bool update = false;
1674	int count = 0;
1675	int all = false;
1676
1677	/* Only update if the ops has been registered */
1678	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1679		return false;
1680
1681	/*
1682	 * In the filter_hash case:
1683	 *   If the count is zero, we update all records.
1684	 *   Otherwise we just update the items in the hash.
1685	 *
1686	 * In the notrace_hash case:
1687	 *   We enable the update in the hash.
1688	 *   As disabling notrace means enabling the tracing,
1689	 *   and enabling notrace means disabling, the inc variable
1690	 *   gets inversed.
1691	 */
1692	if (filter_hash) {
1693		hash = ops->func_hash->filter_hash;
1694		other_hash = ops->func_hash->notrace_hash;
1695		if (ftrace_hash_empty(hash))
1696			all = true;
1697	} else {
1698		inc = !inc;
1699		hash = ops->func_hash->notrace_hash;
1700		other_hash = ops->func_hash->filter_hash;
1701		/*
1702		 * If the notrace hash has no items,
1703		 * then there's nothing to do.
1704		 */
1705		if (ftrace_hash_empty(hash))
1706			return false;
1707	}
1708
1709	do_for_each_ftrace_rec(pg, rec) {
1710		int in_other_hash = 0;
1711		int in_hash = 0;
1712		int match = 0;
1713
1714		if (skip_record(rec))
1715			continue;
1716
1717		if (all) {
1718			/*
1719			 * Only the filter_hash affects all records.
1720			 * Update if the record is not in the notrace hash.
1721			 */
1722			if (!other_hash || !ftrace_lookup_ip(other_hash, rec->ip))
1723				match = 1;
1724		} else {
1725			in_hash = !!ftrace_lookup_ip(hash, rec->ip);
1726			in_other_hash = !!ftrace_lookup_ip(other_hash, rec->ip);
1727
1728			/*
1729			 * If filter_hash is set, we want to match all functions
1730			 * that are in the hash but not in the other hash.
1731			 *
1732			 * If filter_hash is not set, then we are decrementing.
1733			 * That means we match anything that is in the hash
1734			 * and also in the other_hash. That is, we need to turn
1735			 * off functions in the other hash because they are disabled
1736			 * by this hash.
1737			 */
1738			if (filter_hash && in_hash && !in_other_hash)
1739				match = 1;
1740			else if (!filter_hash && in_hash &&
1741				 (in_other_hash || ftrace_hash_empty(other_hash)))
1742				match = 1;
1743		}
1744		if (!match)
1745			continue;
1746
1747		if (inc) {
1748			rec->flags++;
1749			if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX))
1750				return false;
1751
1752			if (ops->flags & FTRACE_OPS_FL_DIRECT)
1753				rec->flags |= FTRACE_FL_DIRECT;
1754
1755			/*
1756			 * If there's only a single callback registered to a
1757			 * function, and the ops has a trampoline registered
1758			 * for it, then we can call it directly.
1759			 */
1760			if (ftrace_rec_count(rec) == 1 && ops->trampoline)
1761				rec->flags |= FTRACE_FL_TRAMP;
1762			else
1763				/*
1764				 * If we are adding another function callback
1765				 * to this function, and the previous had a
1766				 * custom trampoline in use, then we need to go
1767				 * back to the default trampoline.
1768				 */
1769				rec->flags &= ~FTRACE_FL_TRAMP;
1770
1771			/*
1772			 * If any ops wants regs saved for this function
1773			 * then all ops will get saved regs.
1774			 */
1775			if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
1776				rec->flags |= FTRACE_FL_REGS;
1777		} else {
1778			if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0))
1779				return false;
1780			rec->flags--;
1781
1782			/*
1783			 * Only the internal direct_ops should have the
1784			 * DIRECT flag set. Thus, if it is removing a
1785			 * function, then that function should no longer
1786			 * be direct.
1787			 */
1788			if (ops->flags & FTRACE_OPS_FL_DIRECT)
1789				rec->flags &= ~FTRACE_FL_DIRECT;
1790
1791			/*
1792			 * If the rec had REGS enabled and the ops that is
1793			 * being removed had REGS set, then see if there is
1794			 * still any ops for this record that wants regs.
1795			 * If not, we can stop recording them.
1796			 */
1797			if (ftrace_rec_count(rec) > 0 &&
1798			    rec->flags & FTRACE_FL_REGS &&
1799			    ops->flags & FTRACE_OPS_FL_SAVE_REGS) {
1800				if (!test_rec_ops_needs_regs(rec))
1801					rec->flags &= ~FTRACE_FL_REGS;
1802			}
1803
1804			/*
1805			 * The TRAMP needs to be set only if rec count
1806			 * is decremented to one, and the ops that is
1807			 * left has a trampoline. As TRAMP can only be
1808			 * enabled if there is only a single ops attached
1809			 * to it.
1810			 */
1811			if (ftrace_rec_count(rec) == 1 &&
1812			    ftrace_find_tramp_ops_any_other(rec, ops))
1813				rec->flags |= FTRACE_FL_TRAMP;
1814			else
1815				rec->flags &= ~FTRACE_FL_TRAMP;
1816
1817			/*
1818			 * flags will be cleared in ftrace_check_record()
1819			 * if rec count is zero.
1820			 */
1821		}
1822		count++;
1823
1824		/* Must match FTRACE_UPDATE_CALLS in ftrace_modify_all_code() */
1825		update |= ftrace_test_record(rec, true) != FTRACE_UPDATE_IGNORE;
1826
1827		/* Shortcut, if we handled all records, we are done. */
1828		if (!all && count == hash->count)
1829			return update;
1830	} while_for_each_ftrace_rec();
1831
1832	return update;
1833}
1834
1835static bool ftrace_hash_rec_disable(struct ftrace_ops *ops,
1836				    int filter_hash)
1837{
1838	return __ftrace_hash_rec_update(ops, filter_hash, 0);
1839}
1840
1841static bool ftrace_hash_rec_enable(struct ftrace_ops *ops,
1842				   int filter_hash)
1843{
1844	return __ftrace_hash_rec_update(ops, filter_hash, 1);
1845}
1846
1847static void ftrace_hash_rec_update_modify(struct ftrace_ops *ops,
1848					  int filter_hash, int inc)
1849{
1850	struct ftrace_ops *op;
1851
1852	__ftrace_hash_rec_update(ops, filter_hash, inc);
1853
1854	if (ops->func_hash != &global_ops.local_hash)
1855		return;
1856
1857	/*
1858	 * If the ops shares the global_ops hash, then we need to update
1859	 * all ops that are enabled and use this hash.
1860	 */
1861	do_for_each_ftrace_op(op, ftrace_ops_list) {
1862		/* Already done */
1863		if (op == ops)
1864			continue;
1865		if (op->func_hash == &global_ops.local_hash)
1866			__ftrace_hash_rec_update(op, filter_hash, inc);
1867	} while_for_each_ftrace_op(op);
1868}
1869
1870static void ftrace_hash_rec_disable_modify(struct ftrace_ops *ops,
1871					   int filter_hash)
1872{
1873	ftrace_hash_rec_update_modify(ops, filter_hash, 0);
1874}
1875
1876static void ftrace_hash_rec_enable_modify(struct ftrace_ops *ops,
1877					  int filter_hash)
1878{
1879	ftrace_hash_rec_update_modify(ops, filter_hash, 1);
1880}
1881
1882/*
1883 * Try to update IPMODIFY flag on each ftrace_rec. Return 0 if it is OK
1884 * or no-needed to update, -EBUSY if it detects a conflict of the flag
1885 * on a ftrace_rec, and -EINVAL if the new_hash tries to trace all recs.
1886 * Note that old_hash and new_hash has below meanings
1887 *  - If the hash is NULL, it hits all recs (if IPMODIFY is set, this is rejected)
1888 *  - If the hash is EMPTY_HASH, it hits nothing
1889 *  - Anything else hits the recs which match the hash entries.
1890 *
1891 * DIRECT ops does not have IPMODIFY flag, but we still need to check it
1892 * against functions with FTRACE_FL_IPMODIFY. If there is any overlap, call
1893 * ops_func(SHARE_IPMODIFY_SELF) to make sure current ops can share with
1894 * IPMODIFY. If ops_func(SHARE_IPMODIFY_SELF) returns non-zero, propagate
1895 * the return value to the caller and eventually to the owner of the DIRECT
1896 * ops.
1897 */
1898static int __ftrace_hash_update_ipmodify(struct ftrace_ops *ops,
1899					 struct ftrace_hash *old_hash,
1900					 struct ftrace_hash *new_hash)
1901{
1902	struct ftrace_page *pg;
1903	struct dyn_ftrace *rec, *end = NULL;
1904	int in_old, in_new;
1905	bool is_ipmodify, is_direct;
1906
1907	/* Only update if the ops has been registered */
1908	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
1909		return 0;
1910
1911	is_ipmodify = ops->flags & FTRACE_OPS_FL_IPMODIFY;
1912	is_direct = ops->flags & FTRACE_OPS_FL_DIRECT;
1913
1914	/* neither IPMODIFY nor DIRECT, skip */
1915	if (!is_ipmodify && !is_direct)
1916		return 0;
1917
1918	if (WARN_ON_ONCE(is_ipmodify && is_direct))
1919		return 0;
1920
1921	/*
1922	 * Since the IPMODIFY and DIRECT are very address sensitive
1923	 * actions, we do not allow ftrace_ops to set all functions to new
1924	 * hash.
1925	 */
1926	if (!new_hash || !old_hash)
1927		return -EINVAL;
1928
1929	/* Update rec->flags */
1930	do_for_each_ftrace_rec(pg, rec) {
1931
1932		if (rec->flags & FTRACE_FL_DISABLED)
1933			continue;
1934
1935		/* We need to update only differences of filter_hash */
1936		in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1937		in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1938		if (in_old == in_new)
1939			continue;
1940
1941		if (in_new) {
1942			if (rec->flags & FTRACE_FL_IPMODIFY) {
1943				int ret;
1944
1945				/* Cannot have two ipmodify on same rec */
1946				if (is_ipmodify)
1947					goto rollback;
1948
1949				FTRACE_WARN_ON(rec->flags & FTRACE_FL_DIRECT);
1950
1951				/*
1952				 * Another ops with IPMODIFY is already
1953				 * attached. We are now attaching a direct
1954				 * ops. Run SHARE_IPMODIFY_SELF, to check
1955				 * whether sharing is supported.
1956				 */
1957				if (!ops->ops_func)
1958					return -EBUSY;
1959				ret = ops->ops_func(ops, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_SELF);
1960				if (ret)
1961					return ret;
1962			} else if (is_ipmodify) {
1963				rec->flags |= FTRACE_FL_IPMODIFY;
1964			}
1965		} else if (is_ipmodify) {
1966			rec->flags &= ~FTRACE_FL_IPMODIFY;
1967		}
1968	} while_for_each_ftrace_rec();
1969
1970	return 0;
1971
1972rollback:
1973	end = rec;
1974
1975	/* Roll back what we did above */
1976	do_for_each_ftrace_rec(pg, rec) {
1977
1978		if (rec->flags & FTRACE_FL_DISABLED)
1979			continue;
1980
1981		if (rec == end)
1982			goto err_out;
1983
1984		in_old = !!ftrace_lookup_ip(old_hash, rec->ip);
1985		in_new = !!ftrace_lookup_ip(new_hash, rec->ip);
1986		if (in_old == in_new)
1987			continue;
1988
1989		if (in_new)
1990			rec->flags &= ~FTRACE_FL_IPMODIFY;
1991		else
1992			rec->flags |= FTRACE_FL_IPMODIFY;
1993	} while_for_each_ftrace_rec();
1994
1995err_out:
1996	return -EBUSY;
1997}
1998
1999static int ftrace_hash_ipmodify_enable(struct ftrace_ops *ops)
2000{
2001	struct ftrace_hash *hash = ops->func_hash->filter_hash;
2002
2003	if (ftrace_hash_empty(hash))
2004		hash = NULL;
2005
2006	return __ftrace_hash_update_ipmodify(ops, EMPTY_HASH, hash);
2007}
2008
2009/* Disabling always succeeds */
2010static void ftrace_hash_ipmodify_disable(struct ftrace_ops *ops)
2011{
2012	struct ftrace_hash *hash = ops->func_hash->filter_hash;
2013
2014	if (ftrace_hash_empty(hash))
2015		hash = NULL;
2016
2017	__ftrace_hash_update_ipmodify(ops, hash, EMPTY_HASH);
2018}
2019
2020static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
2021				       struct ftrace_hash *new_hash)
2022{
2023	struct ftrace_hash *old_hash = ops->func_hash->filter_hash;
2024
2025	if (ftrace_hash_empty(old_hash))
2026		old_hash = NULL;
2027
2028	if (ftrace_hash_empty(new_hash))
2029		new_hash = NULL;
2030
2031	return __ftrace_hash_update_ipmodify(ops, old_hash, new_hash);
2032}
2033
2034static void print_ip_ins(const char *fmt, const unsigned char *p)
2035{
2036	char ins[MCOUNT_INSN_SIZE];
2037
2038	if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) {
2039		printk(KERN_CONT "%s[FAULT] %px\n", fmt, p);
2040		return;
2041	}
2042
2043	printk(KERN_CONT "%s", fmt);
2044	pr_cont("%*phC", MCOUNT_INSN_SIZE, ins);
 
 
2045}
2046
2047enum ftrace_bug_type ftrace_bug_type;
2048const void *ftrace_expected;
2049
2050static void print_bug_type(void)
2051{
2052	switch (ftrace_bug_type) {
2053	case FTRACE_BUG_UNKNOWN:
2054		break;
2055	case FTRACE_BUG_INIT:
2056		pr_info("Initializing ftrace call sites\n");
2057		break;
2058	case FTRACE_BUG_NOP:
2059		pr_info("Setting ftrace call site to NOP\n");
2060		break;
2061	case FTRACE_BUG_CALL:
2062		pr_info("Setting ftrace call site to call ftrace function\n");
2063		break;
2064	case FTRACE_BUG_UPDATE:
2065		pr_info("Updating ftrace call site to call a different ftrace function\n");
2066		break;
2067	}
2068}
2069
2070/**
2071 * ftrace_bug - report and shutdown function tracer
2072 * @failed: The failed type (EFAULT, EINVAL, EPERM)
2073 * @rec: The record that failed
2074 *
2075 * The arch code that enables or disables the function tracing
2076 * can call ftrace_bug() when it has detected a problem in
2077 * modifying the code. @failed should be one of either:
2078 * EFAULT - if the problem happens on reading the @ip address
2079 * EINVAL - if what is read at @ip is not what was expected
2080 * EPERM - if the problem happens on writing to the @ip address
2081 */
2082void ftrace_bug(int failed, struct dyn_ftrace *rec)
2083{
2084	unsigned long ip = rec ? rec->ip : 0;
2085
2086	pr_info("------------[ ftrace bug ]------------\n");
2087
2088	switch (failed) {
2089	case -EFAULT:
2090		pr_info("ftrace faulted on modifying ");
2091		print_ip_sym(KERN_INFO, ip);
2092		break;
2093	case -EINVAL:
2094		pr_info("ftrace failed to modify ");
2095		print_ip_sym(KERN_INFO, ip);
2096		print_ip_ins(" actual:   ", (unsigned char *)ip);
2097		pr_cont("\n");
2098		if (ftrace_expected) {
2099			print_ip_ins(" expected: ", ftrace_expected);
2100			pr_cont("\n");
2101		}
2102		break;
2103	case -EPERM:
2104		pr_info("ftrace faulted on writing ");
2105		print_ip_sym(KERN_INFO, ip);
2106		break;
2107	default:
2108		pr_info("ftrace faulted on unknown error ");
2109		print_ip_sym(KERN_INFO, ip);
2110	}
2111	print_bug_type();
2112	if (rec) {
2113		struct ftrace_ops *ops = NULL;
2114
2115		pr_info("ftrace record flags: %lx\n", rec->flags);
2116		pr_cont(" (%ld)%s", ftrace_rec_count(rec),
2117			rec->flags & FTRACE_FL_REGS ? " R" : "  ");
2118		if (rec->flags & FTRACE_FL_TRAMP_EN) {
2119			ops = ftrace_find_tramp_ops_any(rec);
2120			if (ops) {
2121				do {
2122					pr_cont("\ttramp: %pS (%pS)",
2123						(void *)ops->trampoline,
2124						(void *)ops->func);
2125					ops = ftrace_find_tramp_ops_next(rec, ops);
2126				} while (ops);
2127			} else
2128				pr_cont("\ttramp: ERROR!");
2129
2130		}
2131		ip = ftrace_get_addr_curr(rec);
2132		pr_cont("\n expected tramp: %lx\n", ip);
2133	}
2134
2135	FTRACE_WARN_ON_ONCE(1);
2136}
2137
2138static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update)
2139{
2140	unsigned long flag = 0UL;
2141
2142	ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2143
2144	if (skip_record(rec))
2145		return FTRACE_UPDATE_IGNORE;
2146
2147	/*
2148	 * If we are updating calls:
2149	 *
2150	 *   If the record has a ref count, then we need to enable it
2151	 *   because someone is using it.
2152	 *
2153	 *   Otherwise we make sure its disabled.
2154	 *
2155	 * If we are disabling calls, then disable all records that
2156	 * are enabled.
2157	 */
2158	if (enable && ftrace_rec_count(rec))
2159		flag = FTRACE_FL_ENABLED;
2160
2161	/*
2162	 * If enabling and the REGS flag does not match the REGS_EN, or
2163	 * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore
2164	 * this record. Set flags to fail the compare against ENABLED.
2165	 * Same for direct calls.
2166	 */
2167	if (flag) {
2168		if (!(rec->flags & FTRACE_FL_REGS) !=
2169		    !(rec->flags & FTRACE_FL_REGS_EN))
2170			flag |= FTRACE_FL_REGS;
2171
2172		if (!(rec->flags & FTRACE_FL_TRAMP) !=
2173		    !(rec->flags & FTRACE_FL_TRAMP_EN))
2174			flag |= FTRACE_FL_TRAMP;
2175
2176		/*
2177		 * Direct calls are special, as count matters.
2178		 * We must test the record for direct, if the
2179		 * DIRECT and DIRECT_EN do not match, but only
2180		 * if the count is 1. That's because, if the
2181		 * count is something other than one, we do not
2182		 * want the direct enabled (it will be done via the
2183		 * direct helper). But if DIRECT_EN is set, and
2184		 * the count is not one, we need to clear it.
2185		 */
2186		if (ftrace_rec_count(rec) == 1) {
2187			if (!(rec->flags & FTRACE_FL_DIRECT) !=
2188			    !(rec->flags & FTRACE_FL_DIRECT_EN))
2189				flag |= FTRACE_FL_DIRECT;
2190		} else if (rec->flags & FTRACE_FL_DIRECT_EN) {
2191			flag |= FTRACE_FL_DIRECT;
2192		}
2193	}
2194
2195	/* If the state of this record hasn't changed, then do nothing */
2196	if ((rec->flags & FTRACE_FL_ENABLED) == flag)
2197		return FTRACE_UPDATE_IGNORE;
2198
2199	if (flag) {
2200		/* Save off if rec is being enabled (for return value) */
2201		flag ^= rec->flags & FTRACE_FL_ENABLED;
2202
2203		if (update) {
2204			rec->flags |= FTRACE_FL_ENABLED;
2205			if (flag & FTRACE_FL_REGS) {
2206				if (rec->flags & FTRACE_FL_REGS)
2207					rec->flags |= FTRACE_FL_REGS_EN;
2208				else
2209					rec->flags &= ~FTRACE_FL_REGS_EN;
2210			}
2211			if (flag & FTRACE_FL_TRAMP) {
2212				if (rec->flags & FTRACE_FL_TRAMP)
2213					rec->flags |= FTRACE_FL_TRAMP_EN;
2214				else
2215					rec->flags &= ~FTRACE_FL_TRAMP_EN;
2216			}
2217
2218			if (flag & FTRACE_FL_DIRECT) {
2219				/*
2220				 * If there's only one user (direct_ops helper)
2221				 * then we can call the direct function
2222				 * directly (no ftrace trampoline).
2223				 */
2224				if (ftrace_rec_count(rec) == 1) {
2225					if (rec->flags & FTRACE_FL_DIRECT)
2226						rec->flags |= FTRACE_FL_DIRECT_EN;
2227					else
2228						rec->flags &= ~FTRACE_FL_DIRECT_EN;
2229				} else {
2230					/*
2231					 * Can only call directly if there's
2232					 * only one callback to the function.
2233					 */
2234					rec->flags &= ~FTRACE_FL_DIRECT_EN;
2235				}
2236			}
2237		}
2238
2239		/*
2240		 * If this record is being updated from a nop, then
2241		 *   return UPDATE_MAKE_CALL.
2242		 * Otherwise,
2243		 *   return UPDATE_MODIFY_CALL to tell the caller to convert
2244		 *   from the save regs, to a non-save regs function or
2245		 *   vice versa, or from a trampoline call.
2246		 */
2247		if (flag & FTRACE_FL_ENABLED) {
2248			ftrace_bug_type = FTRACE_BUG_CALL;
2249			return FTRACE_UPDATE_MAKE_CALL;
2250		}
2251
2252		ftrace_bug_type = FTRACE_BUG_UPDATE;
2253		return FTRACE_UPDATE_MODIFY_CALL;
2254	}
2255
2256	if (update) {
2257		/* If there's no more users, clear all flags */
2258		if (!ftrace_rec_count(rec))
2259			rec->flags &= FTRACE_FL_DISABLED;
2260		else
2261			/*
2262			 * Just disable the record, but keep the ops TRAMP
2263			 * and REGS states. The _EN flags must be disabled though.
2264			 */
2265			rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN |
2266					FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN);
2267	}
2268
2269	ftrace_bug_type = FTRACE_BUG_NOP;
2270	return FTRACE_UPDATE_MAKE_NOP;
2271}
2272
2273/**
2274 * ftrace_update_record - set a record that now is tracing or not
2275 * @rec: the record to update
2276 * @enable: set to true if the record is tracing, false to force disable
2277 *
2278 * The records that represent all functions that can be traced need
2279 * to be updated when tracing has been enabled.
2280 */
2281int ftrace_update_record(struct dyn_ftrace *rec, bool enable)
2282{
2283	return ftrace_check_record(rec, enable, true);
2284}
2285
2286/**
2287 * ftrace_test_record - check if the record has been enabled or not
2288 * @rec: the record to test
2289 * @enable: set to true to check if enabled, false if it is disabled
2290 *
2291 * The arch code may need to test if a record is already set to
2292 * tracing to determine how to modify the function code that it
2293 * represents.
2294 */
2295int ftrace_test_record(struct dyn_ftrace *rec, bool enable)
2296{
2297	return ftrace_check_record(rec, enable, false);
2298}
2299
2300static struct ftrace_ops *
2301ftrace_find_tramp_ops_any(struct dyn_ftrace *rec)
2302{
2303	struct ftrace_ops *op;
2304	unsigned long ip = rec->ip;
2305
2306	do_for_each_ftrace_op(op, ftrace_ops_list) {
2307
2308		if (!op->trampoline)
2309			continue;
2310
2311		if (hash_contains_ip(ip, op->func_hash))
2312			return op;
2313	} while_for_each_ftrace_op(op);
2314
2315	return NULL;
2316}
2317
2318static struct ftrace_ops *
2319ftrace_find_tramp_ops_any_other(struct dyn_ftrace *rec, struct ftrace_ops *op_exclude)
2320{
2321	struct ftrace_ops *op;
2322	unsigned long ip = rec->ip;
2323
2324	do_for_each_ftrace_op(op, ftrace_ops_list) {
2325
2326		if (op == op_exclude || !op->trampoline)
2327			continue;
2328
2329		if (hash_contains_ip(ip, op->func_hash))
2330			return op;
2331	} while_for_each_ftrace_op(op);
2332
2333	return NULL;
2334}
2335
2336static struct ftrace_ops *
2337ftrace_find_tramp_ops_next(struct dyn_ftrace *rec,
2338			   struct ftrace_ops *op)
2339{
2340	unsigned long ip = rec->ip;
2341
2342	while_for_each_ftrace_op(op) {
2343
2344		if (!op->trampoline)
2345			continue;
2346
2347		if (hash_contains_ip(ip, op->func_hash))
2348			return op;
2349	}
2350
2351	return NULL;
2352}
2353
2354static struct ftrace_ops *
2355ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec)
2356{
2357	struct ftrace_ops *op;
2358	unsigned long ip = rec->ip;
2359
2360	/*
2361	 * Need to check removed ops first.
2362	 * If they are being removed, and this rec has a tramp,
2363	 * and this rec is in the ops list, then it would be the
2364	 * one with the tramp.
2365	 */
2366	if (removed_ops) {
2367		if (hash_contains_ip(ip, &removed_ops->old_hash))
2368			return removed_ops;
2369	}
2370
2371	/*
2372	 * Need to find the current trampoline for a rec.
2373	 * Now, a trampoline is only attached to a rec if there
2374	 * was a single 'ops' attached to it. But this can be called
2375	 * when we are adding another op to the rec or removing the
2376	 * current one. Thus, if the op is being added, we can
2377	 * ignore it because it hasn't attached itself to the rec
2378	 * yet.
2379	 *
2380	 * If an ops is being modified (hooking to different functions)
2381	 * then we don't care about the new functions that are being
2382	 * added, just the old ones (that are probably being removed).
2383	 *
2384	 * If we are adding an ops to a function that already is using
2385	 * a trampoline, it needs to be removed (trampolines are only
2386	 * for single ops connected), then an ops that is not being
2387	 * modified also needs to be checked.
2388	 */
2389	do_for_each_ftrace_op(op, ftrace_ops_list) {
2390
2391		if (!op->trampoline)
2392			continue;
2393
2394		/*
2395		 * If the ops is being added, it hasn't gotten to
2396		 * the point to be removed from this tree yet.
2397		 */
2398		if (op->flags & FTRACE_OPS_FL_ADDING)
2399			continue;
2400
2401
2402		/*
2403		 * If the ops is being modified and is in the old
2404		 * hash, then it is probably being removed from this
2405		 * function.
2406		 */
2407		if ((op->flags & FTRACE_OPS_FL_MODIFYING) &&
2408		    hash_contains_ip(ip, &op->old_hash))
2409			return op;
2410		/*
2411		 * If the ops is not being added or modified, and it's
2412		 * in its normal filter hash, then this must be the one
2413		 * we want!
2414		 */
2415		if (!(op->flags & FTRACE_OPS_FL_MODIFYING) &&
2416		    hash_contains_ip(ip, op->func_hash))
2417			return op;
2418
2419	} while_for_each_ftrace_op(op);
2420
2421	return NULL;
2422}
2423
2424static struct ftrace_ops *
2425ftrace_find_tramp_ops_new(struct dyn_ftrace *rec)
2426{
2427	struct ftrace_ops *op;
2428	unsigned long ip = rec->ip;
2429
2430	do_for_each_ftrace_op(op, ftrace_ops_list) {
2431		/* pass rec in as regs to have non-NULL val */
2432		if (hash_contains_ip(ip, op->func_hash))
2433			return op;
2434	} while_for_each_ftrace_op(op);
2435
2436	return NULL;
2437}
2438
2439#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
2440/* Protected by rcu_tasks for reading, and direct_mutex for writing */
2441static struct ftrace_hash *direct_functions = EMPTY_HASH;
2442static DEFINE_MUTEX(direct_mutex);
2443int ftrace_direct_func_count;
2444
2445/*
2446 * Search the direct_functions hash to see if the given instruction pointer
2447 * has a direct caller attached to it.
2448 */
2449unsigned long ftrace_find_rec_direct(unsigned long ip)
2450{
2451	struct ftrace_func_entry *entry;
2452
2453	entry = __ftrace_lookup_ip(direct_functions, ip);
2454	if (!entry)
2455		return 0;
2456
2457	return entry->direct;
2458}
2459
2460static struct ftrace_func_entry*
2461ftrace_add_rec_direct(unsigned long ip, unsigned long addr,
2462		      struct ftrace_hash **free_hash)
2463{
2464	struct ftrace_func_entry *entry;
2465
2466	if (ftrace_hash_empty(direct_functions) ||
2467	    direct_functions->count > 2 * (1 << direct_functions->size_bits)) {
2468		struct ftrace_hash *new_hash;
2469		int size = ftrace_hash_empty(direct_functions) ? 0 :
2470			direct_functions->count + 1;
2471
2472		if (size < 32)
2473			size = 32;
2474
2475		new_hash = dup_hash(direct_functions, size);
2476		if (!new_hash)
2477			return NULL;
2478
2479		*free_hash = direct_functions;
2480		direct_functions = new_hash;
2481	}
2482
2483	entry = kmalloc(sizeof(*entry), GFP_KERNEL);
2484	if (!entry)
2485		return NULL;
2486
2487	entry->ip = ip;
2488	entry->direct = addr;
2489	__add_hash_entry(direct_functions, entry);
2490	return entry;
2491}
2492
2493static void call_direct_funcs(unsigned long ip, unsigned long pip,
2494			      struct ftrace_ops *ops, struct ftrace_regs *fregs)
2495{
2496	unsigned long addr;
2497
2498	addr = ftrace_find_rec_direct(ip);
2499	if (!addr)
2500		return;
2501
2502	arch_ftrace_set_direct_caller(fregs, addr);
2503}
2504
2505struct ftrace_ops direct_ops = {
2506	.func		= call_direct_funcs,
2507	.flags		= FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS
 
2508			  | FTRACE_OPS_FL_PERMANENT,
2509	/*
2510	 * By declaring the main trampoline as this trampoline
2511	 * it will never have one allocated for it. Allocated
2512	 * trampolines should not call direct functions.
2513	 * The direct_ops should only be called by the builtin
2514	 * ftrace_regs_caller trampoline.
2515	 */
2516	.trampoline	= FTRACE_REGS_ADDR,
2517};
2518#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
2519
2520/**
2521 * ftrace_get_addr_new - Get the call address to set to
2522 * @rec:  The ftrace record descriptor
2523 *
2524 * If the record has the FTRACE_FL_REGS set, that means that it
2525 * wants to convert to a callback that saves all regs. If FTRACE_FL_REGS
2526 * is not set, then it wants to convert to the normal callback.
2527 *
2528 * Returns the address of the trampoline to set to
2529 */
2530unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec)
2531{
2532	struct ftrace_ops *ops;
2533	unsigned long addr;
2534
2535	if ((rec->flags & FTRACE_FL_DIRECT) &&
2536	    (ftrace_rec_count(rec) == 1)) {
2537		addr = ftrace_find_rec_direct(rec->ip);
2538		if (addr)
2539			return addr;
2540		WARN_ON_ONCE(1);
2541	}
2542
2543	/* Trampolines take precedence over regs */
2544	if (rec->flags & FTRACE_FL_TRAMP) {
2545		ops = ftrace_find_tramp_ops_new(rec);
2546		if (FTRACE_WARN_ON(!ops || !ops->trampoline)) {
2547			pr_warn("Bad trampoline accounting at: %p (%pS) (%lx)\n",
2548				(void *)rec->ip, (void *)rec->ip, rec->flags);
2549			/* Ftrace is shutting down, return anything */
2550			return (unsigned long)FTRACE_ADDR;
2551		}
2552		return ops->trampoline;
2553	}
2554
2555	if (rec->flags & FTRACE_FL_REGS)
2556		return (unsigned long)FTRACE_REGS_ADDR;
2557	else
2558		return (unsigned long)FTRACE_ADDR;
2559}
2560
2561/**
2562 * ftrace_get_addr_curr - Get the call address that is already there
2563 * @rec:  The ftrace record descriptor
2564 *
2565 * The FTRACE_FL_REGS_EN is set when the record already points to
2566 * a function that saves all the regs. Basically the '_EN' version
2567 * represents the current state of the function.
2568 *
2569 * Returns the address of the trampoline that is currently being called
2570 */
2571unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec)
2572{
2573	struct ftrace_ops *ops;
2574	unsigned long addr;
2575
2576	/* Direct calls take precedence over trampolines */
2577	if (rec->flags & FTRACE_FL_DIRECT_EN) {
2578		addr = ftrace_find_rec_direct(rec->ip);
2579		if (addr)
2580			return addr;
2581		WARN_ON_ONCE(1);
2582	}
2583
2584	/* Trampolines take precedence over regs */
2585	if (rec->flags & FTRACE_FL_TRAMP_EN) {
2586		ops = ftrace_find_tramp_ops_curr(rec);
2587		if (FTRACE_WARN_ON(!ops)) {
2588			pr_warn("Bad trampoline accounting at: %p (%pS)\n",
2589				(void *)rec->ip, (void *)rec->ip);
2590			/* Ftrace is shutting down, return anything */
2591			return (unsigned long)FTRACE_ADDR;
2592		}
2593		return ops->trampoline;
2594	}
2595
2596	if (rec->flags & FTRACE_FL_REGS_EN)
2597		return (unsigned long)FTRACE_REGS_ADDR;
2598	else
2599		return (unsigned long)FTRACE_ADDR;
2600}
2601
2602static int
2603__ftrace_replace_code(struct dyn_ftrace *rec, bool enable)
2604{
2605	unsigned long ftrace_old_addr;
2606	unsigned long ftrace_addr;
2607	int ret;
2608
2609	ftrace_addr = ftrace_get_addr_new(rec);
2610
2611	/* This needs to be done before we call ftrace_update_record */
2612	ftrace_old_addr = ftrace_get_addr_curr(rec);
2613
2614	ret = ftrace_update_record(rec, enable);
2615
2616	ftrace_bug_type = FTRACE_BUG_UNKNOWN;
2617
2618	switch (ret) {
2619	case FTRACE_UPDATE_IGNORE:
2620		return 0;
2621
2622	case FTRACE_UPDATE_MAKE_CALL:
2623		ftrace_bug_type = FTRACE_BUG_CALL;
2624		return ftrace_make_call(rec, ftrace_addr);
2625
2626	case FTRACE_UPDATE_MAKE_NOP:
2627		ftrace_bug_type = FTRACE_BUG_NOP;
2628		return ftrace_make_nop(NULL, rec, ftrace_old_addr);
2629
2630	case FTRACE_UPDATE_MODIFY_CALL:
2631		ftrace_bug_type = FTRACE_BUG_UPDATE;
2632		return ftrace_modify_call(rec, ftrace_old_addr, ftrace_addr);
2633	}
2634
2635	return -1; /* unknown ftrace bug */
2636}
2637
2638void __weak ftrace_replace_code(int mod_flags)
2639{
2640	struct dyn_ftrace *rec;
2641	struct ftrace_page *pg;
2642	bool enable = mod_flags & FTRACE_MODIFY_ENABLE_FL;
2643	int schedulable = mod_flags & FTRACE_MODIFY_MAY_SLEEP_FL;
2644	int failed;
2645
2646	if (unlikely(ftrace_disabled))
2647		return;
2648
2649	do_for_each_ftrace_rec(pg, rec) {
2650
2651		if (skip_record(rec))
2652			continue;
2653
2654		failed = __ftrace_replace_code(rec, enable);
2655		if (failed) {
2656			ftrace_bug(failed, rec);
2657			/* Stop processing */
2658			return;
2659		}
2660		if (schedulable)
2661			cond_resched();
2662	} while_for_each_ftrace_rec();
2663}
2664
2665struct ftrace_rec_iter {
2666	struct ftrace_page	*pg;
2667	int			index;
2668};
2669
2670/**
2671 * ftrace_rec_iter_start - start up iterating over traced functions
2672 *
2673 * Returns an iterator handle that is used to iterate over all
2674 * the records that represent address locations where functions
2675 * are traced.
2676 *
2677 * May return NULL if no records are available.
2678 */
2679struct ftrace_rec_iter *ftrace_rec_iter_start(void)
2680{
2681	/*
2682	 * We only use a single iterator.
2683	 * Protected by the ftrace_lock mutex.
2684	 */
2685	static struct ftrace_rec_iter ftrace_rec_iter;
2686	struct ftrace_rec_iter *iter = &ftrace_rec_iter;
2687
2688	iter->pg = ftrace_pages_start;
2689	iter->index = 0;
2690
2691	/* Could have empty pages */
2692	while (iter->pg && !iter->pg->index)
2693		iter->pg = iter->pg->next;
2694
2695	if (!iter->pg)
2696		return NULL;
2697
2698	return iter;
2699}
2700
2701/**
2702 * ftrace_rec_iter_next - get the next record to process.
2703 * @iter: The handle to the iterator.
2704 *
2705 * Returns the next iterator after the given iterator @iter.
2706 */
2707struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter)
2708{
2709	iter->index++;
2710
2711	if (iter->index >= iter->pg->index) {
2712		iter->pg = iter->pg->next;
2713		iter->index = 0;
2714
2715		/* Could have empty pages */
2716		while (iter->pg && !iter->pg->index)
2717			iter->pg = iter->pg->next;
2718	}
2719
2720	if (!iter->pg)
2721		return NULL;
2722
2723	return iter;
2724}
2725
2726/**
2727 * ftrace_rec_iter_record - get the record at the iterator location
2728 * @iter: The current iterator location
2729 *
2730 * Returns the record that the current @iter is at.
2731 */
2732struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter)
2733{
2734	return &iter->pg->records[iter->index];
2735}
2736
2737static int
2738ftrace_nop_initialize(struct module *mod, struct dyn_ftrace *rec)
2739{
2740	int ret;
2741
2742	if (unlikely(ftrace_disabled))
2743		return 0;
2744
2745	ret = ftrace_init_nop(mod, rec);
2746	if (ret) {
2747		ftrace_bug_type = FTRACE_BUG_INIT;
2748		ftrace_bug(ret, rec);
2749		return 0;
2750	}
2751	return 1;
2752}
2753
2754/*
2755 * archs can override this function if they must do something
2756 * before the modifying code is performed.
2757 */
2758void __weak ftrace_arch_code_modify_prepare(void)
2759{
 
2760}
2761
2762/*
2763 * archs can override this function if they must do something
2764 * after the modifying code is performed.
2765 */
2766void __weak ftrace_arch_code_modify_post_process(void)
2767{
2768}
2769
2770static int update_ftrace_func(ftrace_func_t func)
2771{
2772	static ftrace_func_t save_func;
2773
2774	/* Avoid updating if it hasn't changed */
2775	if (func == save_func)
2776		return 0;
2777
2778	save_func = func;
2779
2780	return ftrace_update_ftrace_func(func);
2781}
2782
2783void ftrace_modify_all_code(int command)
2784{
2785	int update = command & FTRACE_UPDATE_TRACE_FUNC;
2786	int mod_flags = 0;
2787	int err = 0;
2788
2789	if (command & FTRACE_MAY_SLEEP)
2790		mod_flags = FTRACE_MODIFY_MAY_SLEEP_FL;
2791
2792	/*
2793	 * If the ftrace_caller calls a ftrace_ops func directly,
2794	 * we need to make sure that it only traces functions it
2795	 * expects to trace. When doing the switch of functions,
2796	 * we need to update to the ftrace_ops_list_func first
2797	 * before the transition between old and new calls are set,
2798	 * as the ftrace_ops_list_func will check the ops hashes
2799	 * to make sure the ops are having the right functions
2800	 * traced.
2801	 */
2802	if (update) {
2803		err = update_ftrace_func(ftrace_ops_list_func);
2804		if (FTRACE_WARN_ON(err))
2805			return;
2806	}
2807
2808	if (command & FTRACE_UPDATE_CALLS)
2809		ftrace_replace_code(mod_flags | FTRACE_MODIFY_ENABLE_FL);
2810	else if (command & FTRACE_DISABLE_CALLS)
2811		ftrace_replace_code(mod_flags);
2812
2813	if (update && ftrace_trace_function != ftrace_ops_list_func) {
2814		function_trace_op = set_function_trace_op;
2815		smp_wmb();
2816		/* If irqs are disabled, we are in stop machine */
2817		if (!irqs_disabled())
2818			smp_call_function(ftrace_sync_ipi, NULL, 1);
2819		err = update_ftrace_func(ftrace_trace_function);
2820		if (FTRACE_WARN_ON(err))
2821			return;
2822	}
2823
2824	if (command & FTRACE_START_FUNC_RET)
2825		err = ftrace_enable_ftrace_graph_caller();
2826	else if (command & FTRACE_STOP_FUNC_RET)
2827		err = ftrace_disable_ftrace_graph_caller();
2828	FTRACE_WARN_ON(err);
2829}
2830
2831static int __ftrace_modify_code(void *data)
2832{
2833	int *command = data;
2834
2835	ftrace_modify_all_code(*command);
2836
2837	return 0;
2838}
2839
2840/**
2841 * ftrace_run_stop_machine - go back to the stop machine method
2842 * @command: The command to tell ftrace what to do
2843 *
2844 * If an arch needs to fall back to the stop machine method, the
2845 * it can call this function.
2846 */
2847void ftrace_run_stop_machine(int command)
2848{
2849	stop_machine(__ftrace_modify_code, &command, NULL);
2850}
2851
2852/**
2853 * arch_ftrace_update_code - modify the code to trace or not trace
2854 * @command: The command that needs to be done
2855 *
2856 * Archs can override this function if it does not need to
2857 * run stop_machine() to modify code.
2858 */
2859void __weak arch_ftrace_update_code(int command)
2860{
2861	ftrace_run_stop_machine(command);
2862}
2863
2864static void ftrace_run_update_code(int command)
2865{
2866	ftrace_arch_code_modify_prepare();
 
 
 
 
 
2867
2868	/*
2869	 * By default we use stop_machine() to modify the code.
2870	 * But archs can do what ever they want as long as it
2871	 * is safe. The stop_machine() is the safest, but also
2872	 * produces the most overhead.
2873	 */
2874	arch_ftrace_update_code(command);
2875
2876	ftrace_arch_code_modify_post_process();
 
2877}
2878
2879static void ftrace_run_modify_code(struct ftrace_ops *ops, int command,
2880				   struct ftrace_ops_hash *old_hash)
2881{
2882	ops->flags |= FTRACE_OPS_FL_MODIFYING;
2883	ops->old_hash.filter_hash = old_hash->filter_hash;
2884	ops->old_hash.notrace_hash = old_hash->notrace_hash;
2885	ftrace_run_update_code(command);
2886	ops->old_hash.filter_hash = NULL;
2887	ops->old_hash.notrace_hash = NULL;
2888	ops->flags &= ~FTRACE_OPS_FL_MODIFYING;
2889}
2890
2891static ftrace_func_t saved_ftrace_func;
2892static int ftrace_start_up;
2893
2894void __weak arch_ftrace_trampoline_free(struct ftrace_ops *ops)
2895{
2896}
2897
2898/* List of trace_ops that have allocated trampolines */
2899static LIST_HEAD(ftrace_ops_trampoline_list);
2900
2901static void ftrace_add_trampoline_to_kallsyms(struct ftrace_ops *ops)
2902{
2903	lockdep_assert_held(&ftrace_lock);
2904	list_add_rcu(&ops->list, &ftrace_ops_trampoline_list);
2905}
2906
2907static void ftrace_remove_trampoline_from_kallsyms(struct ftrace_ops *ops)
2908{
2909	lockdep_assert_held(&ftrace_lock);
2910	list_del_rcu(&ops->list);
2911	synchronize_rcu();
2912}
2913
2914/*
2915 * "__builtin__ftrace" is used as a module name in /proc/kallsyms for symbols
2916 * for pages allocated for ftrace purposes, even though "__builtin__ftrace" is
2917 * not a module.
2918 */
2919#define FTRACE_TRAMPOLINE_MOD "__builtin__ftrace"
2920#define FTRACE_TRAMPOLINE_SYM "ftrace_trampoline"
2921
2922static void ftrace_trampoline_free(struct ftrace_ops *ops)
2923{
2924	if (ops && (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP) &&
2925	    ops->trampoline) {
2926		/*
2927		 * Record the text poke event before the ksymbol unregister
2928		 * event.
2929		 */
2930		perf_event_text_poke((void *)ops->trampoline,
2931				     (void *)ops->trampoline,
2932				     ops->trampoline_size, NULL, 0);
2933		perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
2934				   ops->trampoline, ops->trampoline_size,
2935				   true, FTRACE_TRAMPOLINE_SYM);
2936		/* Remove from kallsyms after the perf events */
2937		ftrace_remove_trampoline_from_kallsyms(ops);
2938	}
2939
2940	arch_ftrace_trampoline_free(ops);
2941}
2942
2943static void ftrace_startup_enable(int command)
2944{
2945	if (saved_ftrace_func != ftrace_trace_function) {
2946		saved_ftrace_func = ftrace_trace_function;
2947		command |= FTRACE_UPDATE_TRACE_FUNC;
2948	}
2949
2950	if (!command || !ftrace_enabled)
2951		return;
2952
2953	ftrace_run_update_code(command);
2954}
2955
2956static void ftrace_startup_all(int command)
2957{
2958	update_all_ops = true;
2959	ftrace_startup_enable(command);
2960	update_all_ops = false;
2961}
2962
2963int ftrace_startup(struct ftrace_ops *ops, int command)
2964{
2965	int ret;
2966
2967	if (unlikely(ftrace_disabled))
2968		return -ENODEV;
2969
2970	ret = __register_ftrace_function(ops);
2971	if (ret)
2972		return ret;
2973
2974	ftrace_start_up++;
2975
2976	/*
2977	 * Note that ftrace probes uses this to start up
2978	 * and modify functions it will probe. But we still
2979	 * set the ADDING flag for modification, as probes
2980	 * do not have trampolines. If they add them in the
2981	 * future, then the probes will need to distinguish
2982	 * between adding and updating probes.
2983	 */
2984	ops->flags |= FTRACE_OPS_FL_ENABLED | FTRACE_OPS_FL_ADDING;
2985
2986	ret = ftrace_hash_ipmodify_enable(ops);
2987	if (ret < 0) {
2988		/* Rollback registration process */
2989		__unregister_ftrace_function(ops);
2990		ftrace_start_up--;
2991		ops->flags &= ~FTRACE_OPS_FL_ENABLED;
2992		if (ops->flags & FTRACE_OPS_FL_DYNAMIC)
2993			ftrace_trampoline_free(ops);
2994		return ret;
2995	}
2996
2997	if (ftrace_hash_rec_enable(ops, 1))
2998		command |= FTRACE_UPDATE_CALLS;
2999
3000	ftrace_startup_enable(command);
3001
3002	/*
3003	 * If ftrace is in an undefined state, we just remove ops from list
3004	 * to prevent the NULL pointer, instead of totally rolling it back and
3005	 * free trampoline, because those actions could cause further damage.
3006	 */
3007	if (unlikely(ftrace_disabled)) {
3008		__unregister_ftrace_function(ops);
3009		return -ENODEV;
3010	}
3011
3012	ops->flags &= ~FTRACE_OPS_FL_ADDING;
3013
3014	return 0;
3015}
3016
3017int ftrace_shutdown(struct ftrace_ops *ops, int command)
3018{
3019	int ret;
3020
3021	if (unlikely(ftrace_disabled))
3022		return -ENODEV;
3023
3024	ret = __unregister_ftrace_function(ops);
3025	if (ret)
3026		return ret;
3027
3028	ftrace_start_up--;
3029	/*
3030	 * Just warn in case of unbalance, no need to kill ftrace, it's not
3031	 * critical but the ftrace_call callers may be never nopped again after
3032	 * further ftrace uses.
3033	 */
3034	WARN_ON_ONCE(ftrace_start_up < 0);
3035
3036	/* Disabling ipmodify never fails */
3037	ftrace_hash_ipmodify_disable(ops);
3038
3039	if (ftrace_hash_rec_disable(ops, 1))
3040		command |= FTRACE_UPDATE_CALLS;
3041
3042	ops->flags &= ~FTRACE_OPS_FL_ENABLED;
3043
3044	if (saved_ftrace_func != ftrace_trace_function) {
3045		saved_ftrace_func = ftrace_trace_function;
3046		command |= FTRACE_UPDATE_TRACE_FUNC;
3047	}
3048
3049	if (!command || !ftrace_enabled)
3050		goto out;
 
 
 
 
 
 
 
 
 
 
3051
3052	/*
3053	 * If the ops uses a trampoline, then it needs to be
3054	 * tested first on update.
3055	 */
3056	ops->flags |= FTRACE_OPS_FL_REMOVING;
3057	removed_ops = ops;
3058
3059	/* The trampoline logic checks the old hashes */
3060	ops->old_hash.filter_hash = ops->func_hash->filter_hash;
3061	ops->old_hash.notrace_hash = ops->func_hash->notrace_hash;
3062
3063	ftrace_run_update_code(command);
3064
3065	/*
3066	 * If there's no more ops registered with ftrace, run a
3067	 * sanity check to make sure all rec flags are cleared.
3068	 */
3069	if (rcu_dereference_protected(ftrace_ops_list,
3070			lockdep_is_held(&ftrace_lock)) == &ftrace_list_end) {
3071		struct ftrace_page *pg;
3072		struct dyn_ftrace *rec;
3073
3074		do_for_each_ftrace_rec(pg, rec) {
3075			if (FTRACE_WARN_ON_ONCE(rec->flags & ~FTRACE_FL_DISABLED))
3076				pr_warn("  %pS flags:%lx\n",
3077					(void *)rec->ip, rec->flags);
3078		} while_for_each_ftrace_rec();
3079	}
3080
3081	ops->old_hash.filter_hash = NULL;
3082	ops->old_hash.notrace_hash = NULL;
3083
3084	removed_ops = NULL;
3085	ops->flags &= ~FTRACE_OPS_FL_REMOVING;
3086
3087out:
3088	/*
3089	 * Dynamic ops may be freed, we must make sure that all
3090	 * callers are done before leaving this function.
 
 
3091	 */
3092	if (ops->flags & FTRACE_OPS_FL_DYNAMIC) {
3093		/*
3094		 * We need to do a hard force of sched synchronization.
3095		 * This is because we use preempt_disable() to do RCU, but
3096		 * the function tracers can be called where RCU is not watching
3097		 * (like before user_exit()). We can not rely on the RCU
3098		 * infrastructure to do the synchronization, thus we must do it
3099		 * ourselves.
3100		 */
3101		synchronize_rcu_tasks_rude();
3102
3103		/*
3104		 * When the kernel is preemptive, tasks can be preempted
3105		 * while on a ftrace trampoline. Just scheduling a task on
3106		 * a CPU is not good enough to flush them. Calling
3107		 * synchronize_rcu_tasks() will wait for those tasks to
3108		 * execute and either schedule voluntarily or enter user space.
3109		 */
3110		if (IS_ENABLED(CONFIG_PREEMPTION))
3111			synchronize_rcu_tasks();
3112
 
3113		ftrace_trampoline_free(ops);
3114	}
3115
3116	return 0;
3117}
3118
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3119static u64		ftrace_update_time;
3120unsigned long		ftrace_update_tot_cnt;
3121unsigned long		ftrace_number_of_pages;
3122unsigned long		ftrace_number_of_groups;
3123
3124static inline int ops_traces_mod(struct ftrace_ops *ops)
3125{
3126	/*
3127	 * Filter_hash being empty will default to trace module.
3128	 * But notrace hash requires a test of individual module functions.
3129	 */
3130	return ftrace_hash_empty(ops->func_hash->filter_hash) &&
3131		ftrace_hash_empty(ops->func_hash->notrace_hash);
3132}
3133
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3134static int ftrace_update_code(struct module *mod, struct ftrace_page *new_pgs)
3135{
3136	bool init_nop = ftrace_need_init_nop();
3137	struct ftrace_page *pg;
3138	struct dyn_ftrace *p;
3139	u64 start, stop;
3140	unsigned long update_cnt = 0;
3141	unsigned long rec_flags = 0;
3142	int i;
3143
3144	start = ftrace_now(raw_smp_processor_id());
3145
3146	/*
3147	 * When a module is loaded, this function is called to convert
3148	 * the calls to mcount in its text to nops, and also to create
3149	 * an entry in the ftrace data. Now, if ftrace is activated
3150	 * after this call, but before the module sets its text to
3151	 * read-only, the modification of enabling ftrace can fail if
3152	 * the read-only is done while ftrace is converting the calls.
3153	 * To prevent this, the module's records are set as disabled
3154	 * and will be enabled after the call to set the module's text
3155	 * to read-only.
3156	 */
3157	if (mod)
3158		rec_flags |= FTRACE_FL_DISABLED;
3159
3160	for (pg = new_pgs; pg; pg = pg->next) {
3161
3162		for (i = 0; i < pg->index; i++) {
3163
3164			/* If something went wrong, bail without enabling anything */
3165			if (unlikely(ftrace_disabled))
3166				return -1;
3167
3168			p = &pg->records[i];
3169			p->flags = rec_flags;
3170
3171			/*
3172			 * Do the initial record conversion from mcount jump
3173			 * to the NOP instructions.
3174			 */
3175			if (init_nop && !ftrace_nop_initialize(mod, p))
 
3176				break;
3177
3178			update_cnt++;
3179		}
3180	}
3181
3182	stop = ftrace_now(raw_smp_processor_id());
3183	ftrace_update_time = stop - start;
3184	ftrace_update_tot_cnt += update_cnt;
3185
3186	return 0;
3187}
3188
3189static int ftrace_allocate_records(struct ftrace_page *pg, int count)
3190{
3191	int order;
3192	int pages;
3193	int cnt;
3194
3195	if (WARN_ON(!count))
3196		return -EINVAL;
3197
3198	/* We want to fill as much as possible, with no empty pages */
3199	pages = DIV_ROUND_UP(count, ENTRIES_PER_PAGE);
3200	order = fls(pages) - 1;
 
 
 
 
 
3201
3202 again:
3203	pg->records = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
3204
3205	if (!pg->records) {
3206		/* if we can't allocate this size, try something smaller */
3207		if (!order)
3208			return -ENOMEM;
3209		order--;
3210		goto again;
3211	}
3212
3213	ftrace_number_of_pages += 1 << order;
3214	ftrace_number_of_groups++;
3215
3216	cnt = (PAGE_SIZE << order) / ENTRY_SIZE;
3217	pg->order = order;
3218
3219	if (cnt > count)
3220		cnt = count;
3221
3222	return cnt;
3223}
3224
3225static struct ftrace_page *
3226ftrace_allocate_pages(unsigned long num_to_init)
3227{
3228	struct ftrace_page *start_pg;
3229	struct ftrace_page *pg;
 
3230	int cnt;
3231
3232	if (!num_to_init)
3233		return NULL;
3234
3235	start_pg = pg = kzalloc(sizeof(*pg), GFP_KERNEL);
3236	if (!pg)
3237		return NULL;
3238
3239	/*
3240	 * Try to allocate as much as possible in one continues
3241	 * location that fills in all of the space. We want to
3242	 * waste as little space as possible.
3243	 */
3244	for (;;) {
3245		cnt = ftrace_allocate_records(pg, num_to_init);
3246		if (cnt < 0)
3247			goto free_pages;
3248
3249		num_to_init -= cnt;
3250		if (!num_to_init)
3251			break;
3252
3253		pg->next = kzalloc(sizeof(*pg), GFP_KERNEL);
3254		if (!pg->next)
3255			goto free_pages;
3256
3257		pg = pg->next;
3258	}
3259
3260	return start_pg;
3261
3262 free_pages:
3263	pg = start_pg;
3264	while (pg) {
3265		if (pg->records) {
3266			free_pages((unsigned long)pg->records, pg->order);
3267			ftrace_number_of_pages -= 1 << pg->order;
3268		}
3269		start_pg = pg->next;
3270		kfree(pg);
3271		pg = start_pg;
 
3272		ftrace_number_of_groups--;
3273	}
3274	pr_info("ftrace: FAILED to allocate memory for functions\n");
3275	return NULL;
3276}
3277
3278#define FTRACE_BUFF_MAX (KSYM_SYMBOL_LEN+4) /* room for wildcards */
3279
3280struct ftrace_iterator {
3281	loff_t				pos;
3282	loff_t				func_pos;
3283	loff_t				mod_pos;
3284	struct ftrace_page		*pg;
3285	struct dyn_ftrace		*func;
3286	struct ftrace_func_probe	*probe;
3287	struct ftrace_func_entry	*probe_entry;
3288	struct trace_parser		parser;
3289	struct ftrace_hash		*hash;
3290	struct ftrace_ops		*ops;
3291	struct trace_array		*tr;
3292	struct list_head		*mod_list;
3293	int				pidx;
3294	int				idx;
3295	unsigned			flags;
3296};
3297
3298static void *
3299t_probe_next(struct seq_file *m, loff_t *pos)
3300{
3301	struct ftrace_iterator *iter = m->private;
3302	struct trace_array *tr = iter->ops->private;
3303	struct list_head *func_probes;
3304	struct ftrace_hash *hash;
3305	struct list_head *next;
3306	struct hlist_node *hnd = NULL;
3307	struct hlist_head *hhd;
3308	int size;
3309
3310	(*pos)++;
3311	iter->pos = *pos;
3312
3313	if (!tr)
3314		return NULL;
3315
3316	func_probes = &tr->func_probes;
3317	if (list_empty(func_probes))
3318		return NULL;
3319
3320	if (!iter->probe) {
3321		next = func_probes->next;
3322		iter->probe = list_entry(next, struct ftrace_func_probe, list);
3323	}
3324
3325	if (iter->probe_entry)
3326		hnd = &iter->probe_entry->hlist;
3327
3328	hash = iter->probe->ops.func_hash->filter_hash;
3329
3330	/*
3331	 * A probe being registered may temporarily have an empty hash
3332	 * and it's at the end of the func_probes list.
3333	 */
3334	if (!hash || hash == EMPTY_HASH)
3335		return NULL;
3336
3337	size = 1 << hash->size_bits;
3338
3339 retry:
3340	if (iter->pidx >= size) {
3341		if (iter->probe->list.next == func_probes)
3342			return NULL;
3343		next = iter->probe->list.next;
3344		iter->probe = list_entry(next, struct ftrace_func_probe, list);
3345		hash = iter->probe->ops.func_hash->filter_hash;
3346		size = 1 << hash->size_bits;
3347		iter->pidx = 0;
3348	}
3349
3350	hhd = &hash->buckets[iter->pidx];
3351
3352	if (hlist_empty(hhd)) {
3353		iter->pidx++;
3354		hnd = NULL;
3355		goto retry;
3356	}
3357
3358	if (!hnd)
3359		hnd = hhd->first;
3360	else {
3361		hnd = hnd->next;
3362		if (!hnd) {
3363			iter->pidx++;
3364			goto retry;
3365		}
3366	}
3367
3368	if (WARN_ON_ONCE(!hnd))
3369		return NULL;
3370
3371	iter->probe_entry = hlist_entry(hnd, struct ftrace_func_entry, hlist);
3372
3373	return iter;
3374}
3375
3376static void *t_probe_start(struct seq_file *m, loff_t *pos)
3377{
3378	struct ftrace_iterator *iter = m->private;
3379	void *p = NULL;
3380	loff_t l;
3381
3382	if (!(iter->flags & FTRACE_ITER_DO_PROBES))
3383		return NULL;
3384
3385	if (iter->mod_pos > *pos)
3386		return NULL;
3387
3388	iter->probe = NULL;
3389	iter->probe_entry = NULL;
3390	iter->pidx = 0;
3391	for (l = 0; l <= (*pos - iter->mod_pos); ) {
3392		p = t_probe_next(m, &l);
3393		if (!p)
3394			break;
3395	}
3396	if (!p)
3397		return NULL;
3398
3399	/* Only set this if we have an item */
3400	iter->flags |= FTRACE_ITER_PROBE;
3401
3402	return iter;
3403}
3404
3405static int
3406t_probe_show(struct seq_file *m, struct ftrace_iterator *iter)
3407{
3408	struct ftrace_func_entry *probe_entry;
3409	struct ftrace_probe_ops *probe_ops;
3410	struct ftrace_func_probe *probe;
3411
3412	probe = iter->probe;
3413	probe_entry = iter->probe_entry;
3414
3415	if (WARN_ON_ONCE(!probe || !probe_entry))
3416		return -EIO;
3417
3418	probe_ops = probe->probe_ops;
3419
3420	if (probe_ops->print)
3421		return probe_ops->print(m, probe_entry->ip, probe_ops, probe->data);
3422
3423	seq_printf(m, "%ps:%ps\n", (void *)probe_entry->ip,
3424		   (void *)probe_ops->func);
3425
3426	return 0;
3427}
3428
3429static void *
3430t_mod_next(struct seq_file *m, loff_t *pos)
3431{
3432	struct ftrace_iterator *iter = m->private;
3433	struct trace_array *tr = iter->tr;
3434
3435	(*pos)++;
3436	iter->pos = *pos;
3437
3438	iter->mod_list = iter->mod_list->next;
3439
3440	if (iter->mod_list == &tr->mod_trace ||
3441	    iter->mod_list == &tr->mod_notrace) {
3442		iter->flags &= ~FTRACE_ITER_MOD;
3443		return NULL;
3444	}
3445
3446	iter->mod_pos = *pos;
3447
3448	return iter;
3449}
3450
3451static void *t_mod_start(struct seq_file *m, loff_t *pos)
3452{
3453	struct ftrace_iterator *iter = m->private;
3454	void *p = NULL;
3455	loff_t l;
3456
3457	if (iter->func_pos > *pos)
3458		return NULL;
3459
3460	iter->mod_pos = iter->func_pos;
3461
3462	/* probes are only available if tr is set */
3463	if (!iter->tr)
3464		return NULL;
3465
3466	for (l = 0; l <= (*pos - iter->func_pos); ) {
3467		p = t_mod_next(m, &l);
3468		if (!p)
3469			break;
3470	}
3471	if (!p) {
3472		iter->flags &= ~FTRACE_ITER_MOD;
3473		return t_probe_start(m, pos);
3474	}
3475
3476	/* Only set this if we have an item */
3477	iter->flags |= FTRACE_ITER_MOD;
3478
3479	return iter;
3480}
3481
3482static int
3483t_mod_show(struct seq_file *m, struct ftrace_iterator *iter)
3484{
3485	struct ftrace_mod_load *ftrace_mod;
3486	struct trace_array *tr = iter->tr;
3487
3488	if (WARN_ON_ONCE(!iter->mod_list) ||
3489			 iter->mod_list == &tr->mod_trace ||
3490			 iter->mod_list == &tr->mod_notrace)
3491		return -EIO;
3492
3493	ftrace_mod = list_entry(iter->mod_list, struct ftrace_mod_load, list);
3494
3495	if (ftrace_mod->func)
3496		seq_printf(m, "%s", ftrace_mod->func);
3497	else
3498		seq_putc(m, '*');
3499
3500	seq_printf(m, ":mod:%s\n", ftrace_mod->module);
3501
3502	return 0;
3503}
3504
3505static void *
3506t_func_next(struct seq_file *m, loff_t *pos)
3507{
3508	struct ftrace_iterator *iter = m->private;
3509	struct dyn_ftrace *rec = NULL;
3510
3511	(*pos)++;
3512
3513 retry:
3514	if (iter->idx >= iter->pg->index) {
3515		if (iter->pg->next) {
3516			iter->pg = iter->pg->next;
3517			iter->idx = 0;
3518			goto retry;
3519		}
3520	} else {
3521		rec = &iter->pg->records[iter->idx++];
3522		if (((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3523		     !ftrace_lookup_ip(iter->hash, rec->ip)) ||
3524
3525		    ((iter->flags & FTRACE_ITER_ENABLED) &&
3526		     !(rec->flags & FTRACE_FL_ENABLED))) {
3527
3528			rec = NULL;
3529			goto retry;
3530		}
3531	}
3532
3533	if (!rec)
3534		return NULL;
3535
3536	iter->pos = iter->func_pos = *pos;
3537	iter->func = rec;
3538
3539	return iter;
3540}
3541
3542static void *
3543t_next(struct seq_file *m, void *v, loff_t *pos)
3544{
3545	struct ftrace_iterator *iter = m->private;
3546	loff_t l = *pos; /* t_probe_start() must use original pos */
3547	void *ret;
3548
3549	if (unlikely(ftrace_disabled))
3550		return NULL;
3551
3552	if (iter->flags & FTRACE_ITER_PROBE)
3553		return t_probe_next(m, pos);
3554
3555	if (iter->flags & FTRACE_ITER_MOD)
3556		return t_mod_next(m, pos);
3557
3558	if (iter->flags & FTRACE_ITER_PRINTALL) {
3559		/* next must increment pos, and t_probe_start does not */
3560		(*pos)++;
3561		return t_mod_start(m, &l);
3562	}
3563
3564	ret = t_func_next(m, pos);
3565
3566	if (!ret)
3567		return t_mod_start(m, &l);
3568
3569	return ret;
3570}
3571
3572static void reset_iter_read(struct ftrace_iterator *iter)
3573{
3574	iter->pos = 0;
3575	iter->func_pos = 0;
3576	iter->flags &= ~(FTRACE_ITER_PRINTALL | FTRACE_ITER_PROBE | FTRACE_ITER_MOD);
3577}
3578
3579static void *t_start(struct seq_file *m, loff_t *pos)
3580{
3581	struct ftrace_iterator *iter = m->private;
3582	void *p = NULL;
3583	loff_t l;
3584
3585	mutex_lock(&ftrace_lock);
3586
3587	if (unlikely(ftrace_disabled))
3588		return NULL;
3589
3590	/*
3591	 * If an lseek was done, then reset and start from beginning.
3592	 */
3593	if (*pos < iter->pos)
3594		reset_iter_read(iter);
3595
3596	/*
3597	 * For set_ftrace_filter reading, if we have the filter
3598	 * off, we can short cut and just print out that all
3599	 * functions are enabled.
3600	 */
3601	if ((iter->flags & (FTRACE_ITER_FILTER | FTRACE_ITER_NOTRACE)) &&
3602	    ftrace_hash_empty(iter->hash)) {
3603		iter->func_pos = 1; /* Account for the message */
3604		if (*pos > 0)
3605			return t_mod_start(m, pos);
3606		iter->flags |= FTRACE_ITER_PRINTALL;
3607		/* reset in case of seek/pread */
3608		iter->flags &= ~FTRACE_ITER_PROBE;
3609		return iter;
3610	}
3611
3612	if (iter->flags & FTRACE_ITER_MOD)
3613		return t_mod_start(m, pos);
3614
3615	/*
3616	 * Unfortunately, we need to restart at ftrace_pages_start
3617	 * every time we let go of the ftrace_mutex. This is because
3618	 * those pointers can change without the lock.
3619	 */
3620	iter->pg = ftrace_pages_start;
3621	iter->idx = 0;
3622	for (l = 0; l <= *pos; ) {
3623		p = t_func_next(m, &l);
3624		if (!p)
3625			break;
3626	}
3627
3628	if (!p)
3629		return t_mod_start(m, pos);
3630
3631	return iter;
3632}
3633
3634static void t_stop(struct seq_file *m, void *p)
3635{
3636	mutex_unlock(&ftrace_lock);
3637}
3638
3639void * __weak
3640arch_ftrace_trampoline_func(struct ftrace_ops *ops, struct dyn_ftrace *rec)
3641{
3642	return NULL;
3643}
3644
3645static void add_trampoline_func(struct seq_file *m, struct ftrace_ops *ops,
3646				struct dyn_ftrace *rec)
3647{
3648	void *ptr;
3649
3650	ptr = arch_ftrace_trampoline_func(ops, rec);
3651	if (ptr)
3652		seq_printf(m, " ->%pS", ptr);
3653}
3654
3655#ifdef FTRACE_MCOUNT_MAX_OFFSET
3656/*
3657 * Weak functions can still have an mcount/fentry that is saved in
3658 * the __mcount_loc section. These can be detected by having a
3659 * symbol offset of greater than FTRACE_MCOUNT_MAX_OFFSET, as the
3660 * symbol found by kallsyms is not the function that the mcount/fentry
3661 * is part of. The offset is much greater in these cases.
3662 *
3663 * Test the record to make sure that the ip points to a valid kallsyms
3664 * and if not, mark it disabled.
3665 */
3666static int test_for_valid_rec(struct dyn_ftrace *rec)
3667{
3668	char str[KSYM_SYMBOL_LEN];
3669	unsigned long offset;
3670	const char *ret;
3671
3672	ret = kallsyms_lookup(rec->ip, NULL, &offset, NULL, str);
3673
3674	/* Weak functions can cause invalid addresses */
3675	if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3676		rec->flags |= FTRACE_FL_DISABLED;
3677		return 0;
3678	}
3679	return 1;
3680}
3681
3682static struct workqueue_struct *ftrace_check_wq __initdata;
3683static struct work_struct ftrace_check_work __initdata;
3684
3685/*
3686 * Scan all the mcount/fentry entries to make sure they are valid.
3687 */
3688static __init void ftrace_check_work_func(struct work_struct *work)
3689{
3690	struct ftrace_page *pg;
3691	struct dyn_ftrace *rec;
3692
3693	mutex_lock(&ftrace_lock);
3694	do_for_each_ftrace_rec(pg, rec) {
3695		test_for_valid_rec(rec);
3696	} while_for_each_ftrace_rec();
3697	mutex_unlock(&ftrace_lock);
3698}
3699
3700static int __init ftrace_check_for_weak_functions(void)
3701{
3702	INIT_WORK(&ftrace_check_work, ftrace_check_work_func);
3703
3704	ftrace_check_wq = alloc_workqueue("ftrace_check_wq", WQ_UNBOUND, 0);
3705
3706	queue_work(ftrace_check_wq, &ftrace_check_work);
3707	return 0;
3708}
3709
3710static int __init ftrace_check_sync(void)
3711{
3712	/* Make sure the ftrace_check updates are finished */
3713	if (ftrace_check_wq)
3714		destroy_workqueue(ftrace_check_wq);
3715	return 0;
3716}
3717
3718late_initcall_sync(ftrace_check_sync);
3719subsys_initcall(ftrace_check_for_weak_functions);
3720
3721static int print_rec(struct seq_file *m, unsigned long ip)
3722{
3723	unsigned long offset;
3724	char str[KSYM_SYMBOL_LEN];
3725	char *modname;
3726	const char *ret;
3727
3728	ret = kallsyms_lookup(ip, NULL, &offset, &modname, str);
3729	/* Weak functions can cause invalid addresses */
3730	if (!ret || offset > FTRACE_MCOUNT_MAX_OFFSET) {
3731		snprintf(str, KSYM_SYMBOL_LEN, "%s_%ld",
3732			 FTRACE_INVALID_FUNCTION, offset);
3733		ret = NULL;
3734	}
3735
3736	seq_puts(m, str);
3737	if (modname)
3738		seq_printf(m, " [%s]", modname);
3739	return ret == NULL ? -1 : 0;
3740}
3741#else
3742static inline int test_for_valid_rec(struct dyn_ftrace *rec)
3743{
3744	return 1;
3745}
3746
3747static inline int print_rec(struct seq_file *m, unsigned long ip)
3748{
3749	seq_printf(m, "%ps", (void *)ip);
3750	return 0;
3751}
3752#endif
3753
3754static int t_show(struct seq_file *m, void *v)
3755{
3756	struct ftrace_iterator *iter = m->private;
3757	struct dyn_ftrace *rec;
3758
3759	if (iter->flags & FTRACE_ITER_PROBE)
3760		return t_probe_show(m, iter);
3761
3762	if (iter->flags & FTRACE_ITER_MOD)
3763		return t_mod_show(m, iter);
3764
3765	if (iter->flags & FTRACE_ITER_PRINTALL) {
3766		if (iter->flags & FTRACE_ITER_NOTRACE)
3767			seq_puts(m, "#### no functions disabled ####\n");
3768		else
3769			seq_puts(m, "#### all functions enabled ####\n");
3770		return 0;
3771	}
3772
3773	rec = iter->func;
3774
3775	if (!rec)
3776		return 0;
3777
3778	if (print_rec(m, rec->ip)) {
3779		/* This should only happen when a rec is disabled */
3780		WARN_ON_ONCE(!(rec->flags & FTRACE_FL_DISABLED));
3781		seq_putc(m, '\n');
3782		return 0;
3783	}
3784
3785	if (iter->flags & FTRACE_ITER_ENABLED) {
3786		struct ftrace_ops *ops;
3787
3788		seq_printf(m, " (%ld)%s%s%s",
3789			   ftrace_rec_count(rec),
3790			   rec->flags & FTRACE_FL_REGS ? " R" : "  ",
3791			   rec->flags & FTRACE_FL_IPMODIFY ? " I" : "  ",
3792			   rec->flags & FTRACE_FL_DIRECT ? " D" : "  ");
3793		if (rec->flags & FTRACE_FL_TRAMP_EN) {
3794			ops = ftrace_find_tramp_ops_any(rec);
3795			if (ops) {
3796				do {
3797					seq_printf(m, "\ttramp: %pS (%pS)",
3798						   (void *)ops->trampoline,
3799						   (void *)ops->func);
3800					add_trampoline_func(m, ops, rec);
3801					ops = ftrace_find_tramp_ops_next(rec, ops);
3802				} while (ops);
3803			} else
3804				seq_puts(m, "\ttramp: ERROR!");
3805		} else {
3806			add_trampoline_func(m, NULL, rec);
3807		}
3808		if (rec->flags & FTRACE_FL_DIRECT) {
3809			unsigned long direct;
3810
3811			direct = ftrace_find_rec_direct(rec->ip);
3812			if (direct)
3813				seq_printf(m, "\n\tdirect-->%pS", (void *)direct);
3814		}
3815	}
3816
3817	seq_putc(m, '\n');
3818
3819	return 0;
3820}
3821
3822static const struct seq_operations show_ftrace_seq_ops = {
3823	.start = t_start,
3824	.next = t_next,
3825	.stop = t_stop,
3826	.show = t_show,
3827};
3828
3829static int
3830ftrace_avail_open(struct inode *inode, struct file *file)
3831{
3832	struct ftrace_iterator *iter;
3833	int ret;
3834
3835	ret = security_locked_down(LOCKDOWN_TRACEFS);
3836	if (ret)
3837		return ret;
3838
3839	if (unlikely(ftrace_disabled))
3840		return -ENODEV;
3841
3842	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3843	if (!iter)
3844		return -ENOMEM;
3845
3846	iter->pg = ftrace_pages_start;
3847	iter->ops = &global_ops;
3848
3849	return 0;
3850}
3851
3852static int
3853ftrace_enabled_open(struct inode *inode, struct file *file)
3854{
3855	struct ftrace_iterator *iter;
3856
3857	/*
3858	 * This shows us what functions are currently being
3859	 * traced and by what. Not sure if we want lockdown
3860	 * to hide such critical information for an admin.
3861	 * Although, perhaps it can show information we don't
3862	 * want people to see, but if something is tracing
3863	 * something, we probably want to know about it.
3864	 */
3865
3866	iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter));
3867	if (!iter)
3868		return -ENOMEM;
3869
3870	iter->pg = ftrace_pages_start;
3871	iter->flags = FTRACE_ITER_ENABLED;
3872	iter->ops = &global_ops;
3873
3874	return 0;
3875}
3876
3877/**
3878 * ftrace_regex_open - initialize function tracer filter files
3879 * @ops: The ftrace_ops that hold the hash filters
3880 * @flag: The type of filter to process
3881 * @inode: The inode, usually passed in to your open routine
3882 * @file: The file, usually passed in to your open routine
3883 *
3884 * ftrace_regex_open() initializes the filter files for the
3885 * @ops. Depending on @flag it may process the filter hash or
3886 * the notrace hash of @ops. With this called from the open
3887 * routine, you can use ftrace_filter_write() for the write
3888 * routine if @flag has FTRACE_ITER_FILTER set, or
3889 * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
3890 * tracing_lseek() should be used as the lseek routine, and
3891 * release must call ftrace_regex_release().
3892 */
3893int
3894ftrace_regex_open(struct ftrace_ops *ops, int flag,
3895		  struct inode *inode, struct file *file)
3896{
3897	struct ftrace_iterator *iter;
3898	struct ftrace_hash *hash;
3899	struct list_head *mod_head;
3900	struct trace_array *tr = ops->private;
3901	int ret = -ENOMEM;
3902
3903	ftrace_ops_init(ops);
3904
3905	if (unlikely(ftrace_disabled))
3906		return -ENODEV;
3907
3908	if (tracing_check_open_get_tr(tr))
3909		return -ENODEV;
3910
3911	iter = kzalloc(sizeof(*iter), GFP_KERNEL);
3912	if (!iter)
3913		goto out;
3914
3915	if (trace_parser_get_init(&iter->parser, FTRACE_BUFF_MAX))
3916		goto out;
3917
3918	iter->ops = ops;
3919	iter->flags = flag;
3920	iter->tr = tr;
3921
3922	mutex_lock(&ops->func_hash->regex_lock);
3923
3924	if (flag & FTRACE_ITER_NOTRACE) {
3925		hash = ops->func_hash->notrace_hash;
3926		mod_head = tr ? &tr->mod_notrace : NULL;
3927	} else {
3928		hash = ops->func_hash->filter_hash;
3929		mod_head = tr ? &tr->mod_trace : NULL;
3930	}
3931
3932	iter->mod_list = mod_head;
3933
3934	if (file->f_mode & FMODE_WRITE) {
3935		const int size_bits = FTRACE_HASH_DEFAULT_BITS;
3936
3937		if (file->f_flags & O_TRUNC) {
3938			iter->hash = alloc_ftrace_hash(size_bits);
3939			clear_ftrace_mod_list(mod_head);
3940	        } else {
3941			iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash);
3942		}
3943
3944		if (!iter->hash) {
3945			trace_parser_put(&iter->parser);
3946			goto out_unlock;
3947		}
3948	} else
3949		iter->hash = hash;
3950
3951	ret = 0;
3952
3953	if (file->f_mode & FMODE_READ) {
3954		iter->pg = ftrace_pages_start;
3955
3956		ret = seq_open(file, &show_ftrace_seq_ops);
3957		if (!ret) {
3958			struct seq_file *m = file->private_data;
3959			m->private = iter;
3960		} else {
3961			/* Failed */
3962			free_ftrace_hash(iter->hash);
3963			trace_parser_put(&iter->parser);
3964		}
3965	} else
3966		file->private_data = iter;
3967
3968 out_unlock:
3969	mutex_unlock(&ops->func_hash->regex_lock);
3970
3971 out:
3972	if (ret) {
3973		kfree(iter);
3974		if (tr)
3975			trace_array_put(tr);
3976	}
3977
3978	return ret;
3979}
3980
3981static int
3982ftrace_filter_open(struct inode *inode, struct file *file)
3983{
3984	struct ftrace_ops *ops = inode->i_private;
3985
3986	/* Checks for tracefs lockdown */
3987	return ftrace_regex_open(ops,
3988			FTRACE_ITER_FILTER | FTRACE_ITER_DO_PROBES,
3989			inode, file);
3990}
3991
3992static int
3993ftrace_notrace_open(struct inode *inode, struct file *file)
3994{
3995	struct ftrace_ops *ops = inode->i_private;
3996
3997	/* Checks for tracefs lockdown */
3998	return ftrace_regex_open(ops, FTRACE_ITER_NOTRACE,
3999				 inode, file);
4000}
4001
4002/* Type for quick search ftrace basic regexes (globs) from filter_parse_regex */
4003struct ftrace_glob {
4004	char *search;
4005	unsigned len;
4006	int type;
4007};
4008
4009/*
4010 * If symbols in an architecture don't correspond exactly to the user-visible
4011 * name of what they represent, it is possible to define this function to
4012 * perform the necessary adjustments.
4013*/
4014char * __weak arch_ftrace_match_adjust(char *str, const char *search)
4015{
4016	return str;
4017}
4018
4019static int ftrace_match(char *str, struct ftrace_glob *g)
4020{
4021	int matched = 0;
4022	int slen;
4023
4024	str = arch_ftrace_match_adjust(str, g->search);
4025
4026	switch (g->type) {
4027	case MATCH_FULL:
4028		if (strcmp(str, g->search) == 0)
4029			matched = 1;
4030		break;
4031	case MATCH_FRONT_ONLY:
4032		if (strncmp(str, g->search, g->len) == 0)
4033			matched = 1;
4034		break;
4035	case MATCH_MIDDLE_ONLY:
4036		if (strstr(str, g->search))
4037			matched = 1;
4038		break;
4039	case MATCH_END_ONLY:
4040		slen = strlen(str);
4041		if (slen >= g->len &&
4042		    memcmp(str + slen - g->len, g->search, g->len) == 0)
4043			matched = 1;
4044		break;
4045	case MATCH_GLOB:
4046		if (glob_match(g->search, str))
4047			matched = 1;
4048		break;
4049	}
4050
4051	return matched;
4052}
4053
4054static int
4055enter_record(struct ftrace_hash *hash, struct dyn_ftrace *rec, int clear_filter)
4056{
4057	struct ftrace_func_entry *entry;
4058	int ret = 0;
4059
4060	entry = ftrace_lookup_ip(hash, rec->ip);
4061	if (clear_filter) {
4062		/* Do nothing if it doesn't exist */
4063		if (!entry)
4064			return 0;
4065
4066		free_hash_entry(hash, entry);
4067	} else {
4068		/* Do nothing if it exists */
4069		if (entry)
4070			return 0;
4071
4072		ret = add_hash_entry(hash, rec->ip);
4073	}
4074	return ret;
4075}
4076
4077static int
4078add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
4079		 int clear_filter)
4080{
4081	long index = simple_strtoul(func_g->search, NULL, 0);
4082	struct ftrace_page *pg;
4083	struct dyn_ftrace *rec;
4084
4085	/* The index starts at 1 */
4086	if (--index < 0)
4087		return 0;
4088
4089	do_for_each_ftrace_rec(pg, rec) {
4090		if (pg->index <= index) {
4091			index -= pg->index;
4092			/* this is a double loop, break goes to the next page */
4093			break;
4094		}
4095		rec = &pg->records[index];
4096		enter_record(hash, rec, clear_filter);
4097		return 1;
4098	} while_for_each_ftrace_rec();
4099	return 0;
4100}
4101
4102#ifdef FTRACE_MCOUNT_MAX_OFFSET
4103static int lookup_ip(unsigned long ip, char **modname, char *str)
4104{
4105	unsigned long offset;
4106
4107	kallsyms_lookup(ip, NULL, &offset, modname, str);
4108	if (offset > FTRACE_MCOUNT_MAX_OFFSET)
4109		return -1;
4110	return 0;
4111}
4112#else
4113static int lookup_ip(unsigned long ip, char **modname, char *str)
4114{
4115	kallsyms_lookup(ip, NULL, NULL, modname, str);
4116	return 0;
4117}
4118#endif
4119
4120static int
4121ftrace_match_record(struct dyn_ftrace *rec, struct ftrace_glob *func_g,
4122		struct ftrace_glob *mod_g, int exclude_mod)
4123{
4124	char str[KSYM_SYMBOL_LEN];
4125	char *modname;
4126
4127	if (lookup_ip(rec->ip, &modname, str)) {
4128		/* This should only happen when a rec is disabled */
4129		WARN_ON_ONCE(system_state == SYSTEM_RUNNING &&
4130			     !(rec->flags & FTRACE_FL_DISABLED));
4131		return 0;
4132	}
4133
4134	if (mod_g) {
4135		int mod_matches = (modname) ? ftrace_match(modname, mod_g) : 0;
4136
4137		/* blank module name to match all modules */
4138		if (!mod_g->len) {
4139			/* blank module globbing: modname xor exclude_mod */
4140			if (!exclude_mod != !modname)
4141				goto func_match;
4142			return 0;
4143		}
4144
4145		/*
4146		 * exclude_mod is set to trace everything but the given
4147		 * module. If it is set and the module matches, then
4148		 * return 0. If it is not set, and the module doesn't match
4149		 * also return 0. Otherwise, check the function to see if
4150		 * that matches.
4151		 */
4152		if (!mod_matches == !exclude_mod)
4153			return 0;
4154func_match:
4155		/* blank search means to match all funcs in the mod */
4156		if (!func_g->len)
4157			return 1;
4158	}
4159
4160	return ftrace_match(str, func_g);
4161}
4162
4163static int
4164match_records(struct ftrace_hash *hash, char *func, int len, char *mod)
4165{
4166	struct ftrace_page *pg;
4167	struct dyn_ftrace *rec;
4168	struct ftrace_glob func_g = { .type = MATCH_FULL };
4169	struct ftrace_glob mod_g = { .type = MATCH_FULL };
4170	struct ftrace_glob *mod_match = (mod) ? &mod_g : NULL;
4171	int exclude_mod = 0;
4172	int found = 0;
4173	int ret;
4174	int clear_filter = 0;
4175
4176	if (func) {
4177		func_g.type = filter_parse_regex(func, len, &func_g.search,
4178						 &clear_filter);
4179		func_g.len = strlen(func_g.search);
4180	}
4181
4182	if (mod) {
4183		mod_g.type = filter_parse_regex(mod, strlen(mod),
4184				&mod_g.search, &exclude_mod);
4185		mod_g.len = strlen(mod_g.search);
4186	}
4187
4188	mutex_lock(&ftrace_lock);
4189
4190	if (unlikely(ftrace_disabled))
4191		goto out_unlock;
4192
4193	if (func_g.type == MATCH_INDEX) {
4194		found = add_rec_by_index(hash, &func_g, clear_filter);
4195		goto out_unlock;
4196	}
4197
4198	do_for_each_ftrace_rec(pg, rec) {
4199
4200		if (rec->flags & FTRACE_FL_DISABLED)
4201			continue;
4202
4203		if (ftrace_match_record(rec, &func_g, mod_match, exclude_mod)) {
4204			ret = enter_record(hash, rec, clear_filter);
4205			if (ret < 0) {
4206				found = ret;
4207				goto out_unlock;
4208			}
4209			found = 1;
4210		}
4211		cond_resched();
4212	} while_for_each_ftrace_rec();
4213 out_unlock:
4214	mutex_unlock(&ftrace_lock);
4215
4216	return found;
4217}
4218
4219static int
4220ftrace_match_records(struct ftrace_hash *hash, char *buff, int len)
4221{
4222	return match_records(hash, buff, len, NULL);
4223}
4224
4225static void ftrace_ops_update_code(struct ftrace_ops *ops,
4226				   struct ftrace_ops_hash *old_hash)
4227{
4228	struct ftrace_ops *op;
4229
4230	if (!ftrace_enabled)
4231		return;
4232
4233	if (ops->flags & FTRACE_OPS_FL_ENABLED) {
4234		ftrace_run_modify_code(ops, FTRACE_UPDATE_CALLS, old_hash);
4235		return;
4236	}
4237
4238	/*
4239	 * If this is the shared global_ops filter, then we need to
4240	 * check if there is another ops that shares it, is enabled.
4241	 * If so, we still need to run the modify code.
4242	 */
4243	if (ops->func_hash != &global_ops.local_hash)
4244		return;
4245
4246	do_for_each_ftrace_op(op, ftrace_ops_list) {
4247		if (op->func_hash == &global_ops.local_hash &&
4248		    op->flags & FTRACE_OPS_FL_ENABLED) {
4249			ftrace_run_modify_code(op, FTRACE_UPDATE_CALLS, old_hash);
4250			/* Only need to do this once */
4251			return;
4252		}
4253	} while_for_each_ftrace_op(op);
4254}
4255
4256static int ftrace_hash_move_and_update_ops(struct ftrace_ops *ops,
4257					   struct ftrace_hash **orig_hash,
4258					   struct ftrace_hash *hash,
4259					   int enable)
4260{
4261	struct ftrace_ops_hash old_hash_ops;
4262	struct ftrace_hash *old_hash;
4263	int ret;
4264
4265	old_hash = *orig_hash;
4266	old_hash_ops.filter_hash = ops->func_hash->filter_hash;
4267	old_hash_ops.notrace_hash = ops->func_hash->notrace_hash;
4268	ret = ftrace_hash_move(ops, enable, orig_hash, hash);
4269	if (!ret) {
4270		ftrace_ops_update_code(ops, &old_hash_ops);
4271		free_ftrace_hash_rcu(old_hash);
4272	}
4273	return ret;
4274}
4275
4276static bool module_exists(const char *module)
4277{
4278	/* All modules have the symbol __this_module */
4279	static const char this_mod[] = "__this_module";
4280	char modname[MAX_PARAM_PREFIX_LEN + sizeof(this_mod) + 2];
4281	unsigned long val;
4282	int n;
4283
4284	n = snprintf(modname, sizeof(modname), "%s:%s", module, this_mod);
4285
4286	if (n > sizeof(modname) - 1)
4287		return false;
4288
4289	val = module_kallsyms_lookup_name(modname);
4290	return val != 0;
4291}
4292
4293static int cache_mod(struct trace_array *tr,
4294		     const char *func, char *module, int enable)
4295{
4296	struct ftrace_mod_load *ftrace_mod, *n;
4297	struct list_head *head = enable ? &tr->mod_trace : &tr->mod_notrace;
4298	int ret;
4299
4300	mutex_lock(&ftrace_lock);
4301
4302	/* We do not cache inverse filters */
4303	if (func[0] == '!') {
4304		func++;
4305		ret = -EINVAL;
4306
4307		/* Look to remove this hash */
4308		list_for_each_entry_safe(ftrace_mod, n, head, list) {
4309			if (strcmp(ftrace_mod->module, module) != 0)
4310				continue;
4311
4312			/* no func matches all */
4313			if (strcmp(func, "*") == 0 ||
4314			    (ftrace_mod->func &&
4315			     strcmp(ftrace_mod->func, func) == 0)) {
4316				ret = 0;
4317				free_ftrace_mod(ftrace_mod);
4318				continue;
4319			}
4320		}
4321		goto out;
4322	}
4323
4324	ret = -EINVAL;
4325	/* We only care about modules that have not been loaded yet */
4326	if (module_exists(module))
4327		goto out;
4328
4329	/* Save this string off, and execute it when the module is loaded */
4330	ret = ftrace_add_mod(tr, func, module, enable);
4331 out:
4332	mutex_unlock(&ftrace_lock);
4333
4334	return ret;
4335}
4336
4337static int
4338ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
4339		 int reset, int enable);
4340
4341#ifdef CONFIG_MODULES
4342static void process_mod_list(struct list_head *head, struct ftrace_ops *ops,
4343			     char *mod, bool enable)
4344{
4345	struct ftrace_mod_load *ftrace_mod, *n;
4346	struct ftrace_hash **orig_hash, *new_hash;
4347	LIST_HEAD(process_mods);
4348	char *func;
 
4349
4350	mutex_lock(&ops->func_hash->regex_lock);
4351
4352	if (enable)
4353		orig_hash = &ops->func_hash->filter_hash;
4354	else
4355		orig_hash = &ops->func_hash->notrace_hash;
4356
4357	new_hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS,
4358					      *orig_hash);
4359	if (!new_hash)
4360		goto out; /* warn? */
4361
4362	mutex_lock(&ftrace_lock);
4363
4364	list_for_each_entry_safe(ftrace_mod, n, head, list) {
4365
4366		if (strcmp(ftrace_mod->module, mod) != 0)
4367			continue;
4368
4369		if (ftrace_mod->func)
4370			func = kstrdup(ftrace_mod->func, GFP_KERNEL);
4371		else
4372			func = kstrdup("*", GFP_KERNEL);
4373
4374		if (!func) /* warn? */
4375			continue;
4376
4377		list_move(&ftrace_mod->list, &process_mods);
 
4378
4379		/* Use the newly allocated func, as it may be "*" */
4380		kfree(ftrace_mod->func);
4381		ftrace_mod->func = func;
4382	}
4383
4384	mutex_unlock(&ftrace_lock);
4385
4386	list_for_each_entry_safe(ftrace_mod, n, &process_mods, list) {
4387
4388		func = ftrace_mod->func;
4389
4390		/* Grabs ftrace_lock, which is why we have this extra step */
4391		match_records(new_hash, func, strlen(func), mod);
4392		free_ftrace_mod(ftrace_mod);
4393	}
4394
4395	if (enable && list_empty(head))
4396		new_hash->flags &= ~FTRACE_HASH_FL_MOD;
4397
4398	mutex_lock(&ftrace_lock);
4399
4400	ftrace_hash_move_and_update_ops(ops, orig_hash,
4401					      new_hash, enable);
4402	mutex_unlock(&ftrace_lock);
4403
4404 out:
4405	mutex_unlock(&ops->func_hash->regex_lock);
4406
4407	free_ftrace_hash(new_hash);
4408}
4409
4410static void process_cached_mods(const char *mod_name)
4411{
4412	struct trace_array *tr;
4413	char *mod;
4414
4415	mod = kstrdup(mod_name, GFP_KERNEL);
4416	if (!mod)
4417		return;
4418
4419	mutex_lock(&trace_types_lock);
4420	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
4421		if (!list_empty(&tr->mod_trace))
4422			process_mod_list(&tr->mod_trace, tr->ops, mod, true);
4423		if (!list_empty(&tr->mod_notrace))
4424			process_mod_list(&tr->mod_notrace, tr->ops, mod, false);
4425	}
4426	mutex_unlock(&trace_types_lock);
4427
4428	kfree(mod);
4429}
4430#endif
4431
4432/*
4433 * We register the module command as a template to show others how
4434 * to register the a command as well.
4435 */
4436
4437static int
4438ftrace_mod_callback(struct trace_array *tr, struct ftrace_hash *hash,
4439		    char *func_orig, char *cmd, char *module, int enable)
4440{
4441	char *func;
4442	int ret;
4443
4444	/* match_records() modifies func, and we need the original */
4445	func = kstrdup(func_orig, GFP_KERNEL);
4446	if (!func)
4447		return -ENOMEM;
4448
4449	/*
4450	 * cmd == 'mod' because we only registered this func
4451	 * for the 'mod' ftrace_func_command.
4452	 * But if you register one func with multiple commands,
4453	 * you can tell which command was used by the cmd
4454	 * parameter.
4455	 */
4456	ret = match_records(hash, func, strlen(func), module);
4457	kfree(func);
4458
4459	if (!ret)
4460		return cache_mod(tr, func_orig, module, enable);
4461	if (ret < 0)
4462		return ret;
4463	return 0;
4464}
4465
4466static struct ftrace_func_command ftrace_mod_cmd = {
4467	.name			= "mod",
4468	.func			= ftrace_mod_callback,
4469};
4470
4471static int __init ftrace_mod_cmd_init(void)
4472{
4473	return register_ftrace_command(&ftrace_mod_cmd);
4474}
4475core_initcall(ftrace_mod_cmd_init);
4476
4477static void function_trace_probe_call(unsigned long ip, unsigned long parent_ip,
4478				      struct ftrace_ops *op, struct ftrace_regs *fregs)
4479{
4480	struct ftrace_probe_ops *probe_ops;
4481	struct ftrace_func_probe *probe;
4482
4483	probe = container_of(op, struct ftrace_func_probe, ops);
4484	probe_ops = probe->probe_ops;
4485
4486	/*
4487	 * Disable preemption for these calls to prevent a RCU grace
4488	 * period. This syncs the hash iteration and freeing of items
4489	 * on the hash. rcu_read_lock is too dangerous here.
4490	 */
4491	preempt_disable_notrace();
4492	probe_ops->func(ip, parent_ip, probe->tr, probe_ops, probe->data);
4493	preempt_enable_notrace();
4494}
4495
4496struct ftrace_func_map {
4497	struct ftrace_func_entry	entry;
4498	void				*data;
4499};
4500
4501struct ftrace_func_mapper {
4502	struct ftrace_hash		hash;
4503};
4504
4505/**
4506 * allocate_ftrace_func_mapper - allocate a new ftrace_func_mapper
4507 *
4508 * Returns a ftrace_func_mapper descriptor that can be used to map ips to data.
4509 */
4510struct ftrace_func_mapper *allocate_ftrace_func_mapper(void)
4511{
4512	struct ftrace_hash *hash;
4513
4514	/*
4515	 * The mapper is simply a ftrace_hash, but since the entries
4516	 * in the hash are not ftrace_func_entry type, we define it
4517	 * as a separate structure.
4518	 */
4519	hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
4520	return (struct ftrace_func_mapper *)hash;
4521}
4522
4523/**
4524 * ftrace_func_mapper_find_ip - Find some data mapped to an ip
4525 * @mapper: The mapper that has the ip maps
4526 * @ip: the instruction pointer to find the data for
4527 *
4528 * Returns the data mapped to @ip if found otherwise NULL. The return
4529 * is actually the address of the mapper data pointer. The address is
4530 * returned for use cases where the data is no bigger than a long, and
4531 * the user can use the data pointer as its data instead of having to
4532 * allocate more memory for the reference.
4533 */
4534void **ftrace_func_mapper_find_ip(struct ftrace_func_mapper *mapper,
4535				  unsigned long ip)
4536{
4537	struct ftrace_func_entry *entry;
4538	struct ftrace_func_map *map;
4539
4540	entry = ftrace_lookup_ip(&mapper->hash, ip);
4541	if (!entry)
4542		return NULL;
4543
4544	map = (struct ftrace_func_map *)entry;
4545	return &map->data;
4546}
4547
4548/**
4549 * ftrace_func_mapper_add_ip - Map some data to an ip
4550 * @mapper: The mapper that has the ip maps
4551 * @ip: The instruction pointer address to map @data to
4552 * @data: The data to map to @ip
4553 *
4554 * Returns 0 on success otherwise an error.
4555 */
4556int ftrace_func_mapper_add_ip(struct ftrace_func_mapper *mapper,
4557			      unsigned long ip, void *data)
4558{
4559	struct ftrace_func_entry *entry;
4560	struct ftrace_func_map *map;
4561
4562	entry = ftrace_lookup_ip(&mapper->hash, ip);
4563	if (entry)
4564		return -EBUSY;
4565
4566	map = kmalloc(sizeof(*map), GFP_KERNEL);
4567	if (!map)
4568		return -ENOMEM;
4569
4570	map->entry.ip = ip;
4571	map->data = data;
4572
4573	__add_hash_entry(&mapper->hash, &map->entry);
4574
4575	return 0;
4576}
4577
4578/**
4579 * ftrace_func_mapper_remove_ip - Remove an ip from the mapping
4580 * @mapper: The mapper that has the ip maps
4581 * @ip: The instruction pointer address to remove the data from
4582 *
4583 * Returns the data if it is found, otherwise NULL.
4584 * Note, if the data pointer is used as the data itself, (see
4585 * ftrace_func_mapper_find_ip(), then the return value may be meaningless,
4586 * if the data pointer was set to zero.
4587 */
4588void *ftrace_func_mapper_remove_ip(struct ftrace_func_mapper *mapper,
4589				   unsigned long ip)
4590{
4591	struct ftrace_func_entry *entry;
4592	struct ftrace_func_map *map;
4593	void *data;
4594
4595	entry = ftrace_lookup_ip(&mapper->hash, ip);
4596	if (!entry)
4597		return NULL;
4598
4599	map = (struct ftrace_func_map *)entry;
4600	data = map->data;
4601
4602	remove_hash_entry(&mapper->hash, entry);
4603	kfree(entry);
4604
4605	return data;
4606}
4607
4608/**
4609 * free_ftrace_func_mapper - free a mapping of ips and data
4610 * @mapper: The mapper that has the ip maps
4611 * @free_func: A function to be called on each data item.
4612 *
4613 * This is used to free the function mapper. The @free_func is optional
4614 * and can be used if the data needs to be freed as well.
4615 */
4616void free_ftrace_func_mapper(struct ftrace_func_mapper *mapper,
4617			     ftrace_mapper_func free_func)
4618{
4619	struct ftrace_func_entry *entry;
4620	struct ftrace_func_map *map;
4621	struct hlist_head *hhd;
4622	int size, i;
4623
4624	if (!mapper)
4625		return;
4626
4627	if (free_func && mapper->hash.count) {
4628		size = 1 << mapper->hash.size_bits;
4629		for (i = 0; i < size; i++) {
4630			hhd = &mapper->hash.buckets[i];
4631			hlist_for_each_entry(entry, hhd, hlist) {
4632				map = (struct ftrace_func_map *)entry;
4633				free_func(map);
4634			}
4635		}
4636	}
4637	free_ftrace_hash(&mapper->hash);
4638}
4639
4640static void release_probe(struct ftrace_func_probe *probe)
4641{
4642	struct ftrace_probe_ops *probe_ops;
4643
4644	mutex_lock(&ftrace_lock);
4645
4646	WARN_ON(probe->ref <= 0);
4647
4648	/* Subtract the ref that was used to protect this instance */
4649	probe->ref--;
4650
4651	if (!probe->ref) {
4652		probe_ops = probe->probe_ops;
4653		/*
4654		 * Sending zero as ip tells probe_ops to free
4655		 * the probe->data itself
4656		 */
4657		if (probe_ops->free)
4658			probe_ops->free(probe_ops, probe->tr, 0, probe->data);
4659		list_del(&probe->list);
4660		kfree(probe);
4661	}
4662	mutex_unlock(&ftrace_lock);
4663}
4664
4665static void acquire_probe_locked(struct ftrace_func_probe *probe)
4666{
4667	/*
4668	 * Add one ref to keep it from being freed when releasing the
4669	 * ftrace_lock mutex.
4670	 */
4671	probe->ref++;
4672}
4673
4674int
4675register_ftrace_function_probe(char *glob, struct trace_array *tr,
4676			       struct ftrace_probe_ops *probe_ops,
4677			       void *data)
4678{
4679	struct ftrace_func_probe *probe = NULL, *iter;
4680	struct ftrace_func_entry *entry;
 
4681	struct ftrace_hash **orig_hash;
4682	struct ftrace_hash *old_hash;
4683	struct ftrace_hash *hash;
4684	int count = 0;
4685	int size;
4686	int ret;
4687	int i;
4688
4689	if (WARN_ON(!tr))
4690		return -EINVAL;
4691
4692	/* We do not support '!' for function probes */
4693	if (WARN_ON(glob[0] == '!'))
4694		return -EINVAL;
4695
4696
4697	mutex_lock(&ftrace_lock);
4698	/* Check if the probe_ops is already registered */
4699	list_for_each_entry(iter, &tr->func_probes, list) {
4700		if (iter->probe_ops == probe_ops) {
4701			probe = iter;
4702			break;
4703		}
4704	}
4705	if (!probe) {
4706		probe = kzalloc(sizeof(*probe), GFP_KERNEL);
4707		if (!probe) {
4708			mutex_unlock(&ftrace_lock);
4709			return -ENOMEM;
4710		}
4711		probe->probe_ops = probe_ops;
4712		probe->ops.func = function_trace_probe_call;
4713		probe->tr = tr;
4714		ftrace_ops_init(&probe->ops);
4715		list_add(&probe->list, &tr->func_probes);
4716	}
4717
4718	acquire_probe_locked(probe);
4719
4720	mutex_unlock(&ftrace_lock);
4721
4722	/*
4723	 * Note, there's a small window here that the func_hash->filter_hash
4724	 * may be NULL or empty. Need to be careful when reading the loop.
4725	 */
4726	mutex_lock(&probe->ops.func_hash->regex_lock);
4727
4728	orig_hash = &probe->ops.func_hash->filter_hash;
4729	old_hash = *orig_hash;
4730	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4731
4732	if (!hash) {
4733		ret = -ENOMEM;
4734		goto out;
4735	}
4736
4737	ret = ftrace_match_records(hash, glob, strlen(glob));
4738
4739	/* Nothing found? */
4740	if (!ret)
4741		ret = -EINVAL;
4742
4743	if (ret < 0)
4744		goto out;
4745
4746	size = 1 << hash->size_bits;
4747	for (i = 0; i < size; i++) {
4748		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4749			if (ftrace_lookup_ip(old_hash, entry->ip))
4750				continue;
4751			/*
4752			 * The caller might want to do something special
4753			 * for each function we find. We call the callback
4754			 * to give the caller an opportunity to do so.
4755			 */
4756			if (probe_ops->init) {
4757				ret = probe_ops->init(probe_ops, tr,
4758						      entry->ip, data,
4759						      &probe->data);
4760				if (ret < 0) {
4761					if (probe_ops->free && count)
4762						probe_ops->free(probe_ops, tr,
4763								0, probe->data);
4764					probe->data = NULL;
4765					goto out;
4766				}
4767			}
4768			count++;
4769		}
4770	}
4771
4772	mutex_lock(&ftrace_lock);
4773
4774	if (!count) {
4775		/* Nothing was added? */
4776		ret = -EINVAL;
4777		goto out_unlock;
4778	}
4779
4780	ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4781					      hash, 1);
4782	if (ret < 0)
4783		goto err_unlock;
4784
4785	/* One ref for each new function traced */
4786	probe->ref += count;
4787
4788	if (!(probe->ops.flags & FTRACE_OPS_FL_ENABLED))
4789		ret = ftrace_startup(&probe->ops, 0);
4790
4791 out_unlock:
4792	mutex_unlock(&ftrace_lock);
4793
4794	if (!ret)
4795		ret = count;
4796 out:
4797	mutex_unlock(&probe->ops.func_hash->regex_lock);
4798	free_ftrace_hash(hash);
4799
4800	release_probe(probe);
4801
4802	return ret;
4803
4804 err_unlock:
4805	if (!probe_ops->free || !count)
4806		goto out_unlock;
4807
4808	/* Failed to do the move, need to call the free functions */
4809	for (i = 0; i < size; i++) {
4810		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
4811			if (ftrace_lookup_ip(old_hash, entry->ip))
4812				continue;
4813			probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4814		}
4815	}
4816	goto out_unlock;
4817}
4818
4819int
4820unregister_ftrace_function_probe_func(char *glob, struct trace_array *tr,
4821				      struct ftrace_probe_ops *probe_ops)
4822{
4823	struct ftrace_func_probe *probe = NULL, *iter;
4824	struct ftrace_ops_hash old_hash_ops;
4825	struct ftrace_func_entry *entry;
 
4826	struct ftrace_glob func_g;
4827	struct ftrace_hash **orig_hash;
4828	struct ftrace_hash *old_hash;
4829	struct ftrace_hash *hash = NULL;
4830	struct hlist_node *tmp;
4831	struct hlist_head hhd;
4832	char str[KSYM_SYMBOL_LEN];
4833	int count = 0;
4834	int i, ret = -ENODEV;
4835	int size;
4836
4837	if (!glob || !strlen(glob) || !strcmp(glob, "*"))
4838		func_g.search = NULL;
4839	else {
4840		int not;
4841
4842		func_g.type = filter_parse_regex(glob, strlen(glob),
4843						 &func_g.search, &not);
4844		func_g.len = strlen(func_g.search);
4845
4846		/* we do not support '!' for function probes */
4847		if (WARN_ON(not))
4848			return -EINVAL;
4849	}
4850
4851	mutex_lock(&ftrace_lock);
4852	/* Check if the probe_ops is already registered */
4853	list_for_each_entry(iter, &tr->func_probes, list) {
4854		if (iter->probe_ops == probe_ops) {
4855			probe = iter;
4856			break;
4857		}
4858	}
4859	if (!probe)
4860		goto err_unlock_ftrace;
4861
4862	ret = -EINVAL;
4863	if (!(probe->ops.flags & FTRACE_OPS_FL_INITIALIZED))
4864		goto err_unlock_ftrace;
4865
4866	acquire_probe_locked(probe);
4867
4868	mutex_unlock(&ftrace_lock);
4869
4870	mutex_lock(&probe->ops.func_hash->regex_lock);
4871
4872	orig_hash = &probe->ops.func_hash->filter_hash;
4873	old_hash = *orig_hash;
4874
4875	if (ftrace_hash_empty(old_hash))
4876		goto out_unlock;
4877
4878	old_hash_ops.filter_hash = old_hash;
4879	/* Probes only have filters */
4880	old_hash_ops.notrace_hash = NULL;
4881
4882	ret = -ENOMEM;
4883	hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
4884	if (!hash)
4885		goto out_unlock;
4886
4887	INIT_HLIST_HEAD(&hhd);
4888
4889	size = 1 << hash->size_bits;
4890	for (i = 0; i < size; i++) {
4891		hlist_for_each_entry_safe(entry, tmp, &hash->buckets[i], hlist) {
4892
4893			if (func_g.search) {
4894				kallsyms_lookup(entry->ip, NULL, NULL,
4895						NULL, str);
4896				if (!ftrace_match(str, &func_g))
4897					continue;
4898			}
4899			count++;
4900			remove_hash_entry(hash, entry);
4901			hlist_add_head(&entry->hlist, &hhd);
4902		}
4903	}
4904
4905	/* Nothing found? */
4906	if (!count) {
4907		ret = -EINVAL;
4908		goto out_unlock;
4909	}
4910
4911	mutex_lock(&ftrace_lock);
4912
4913	WARN_ON(probe->ref < count);
4914
4915	probe->ref -= count;
4916
4917	if (ftrace_hash_empty(hash))
4918		ftrace_shutdown(&probe->ops, 0);
4919
4920	ret = ftrace_hash_move_and_update_ops(&probe->ops, orig_hash,
4921					      hash, 1);
4922
4923	/* still need to update the function call sites */
4924	if (ftrace_enabled && !ftrace_hash_empty(hash))
4925		ftrace_run_modify_code(&probe->ops, FTRACE_UPDATE_CALLS,
4926				       &old_hash_ops);
4927	synchronize_rcu();
4928
4929	hlist_for_each_entry_safe(entry, tmp, &hhd, hlist) {
4930		hlist_del(&entry->hlist);
4931		if (probe_ops->free)
4932			probe_ops->free(probe_ops, tr, entry->ip, probe->data);
4933		kfree(entry);
4934	}
4935	mutex_unlock(&ftrace_lock);
4936
4937 out_unlock:
4938	mutex_unlock(&probe->ops.func_hash->regex_lock);
4939	free_ftrace_hash(hash);
4940
4941	release_probe(probe);
4942
4943	return ret;
4944
4945 err_unlock_ftrace:
4946	mutex_unlock(&ftrace_lock);
4947	return ret;
4948}
4949
4950void clear_ftrace_function_probes(struct trace_array *tr)
4951{
4952	struct ftrace_func_probe *probe, *n;
4953
4954	list_for_each_entry_safe(probe, n, &tr->func_probes, list)
4955		unregister_ftrace_function_probe_func(NULL, tr, probe->probe_ops);
4956}
4957
4958static LIST_HEAD(ftrace_commands);
4959static DEFINE_MUTEX(ftrace_cmd_mutex);
4960
4961/*
4962 * Currently we only register ftrace commands from __init, so mark this
4963 * __init too.
4964 */
4965__init int register_ftrace_command(struct ftrace_func_command *cmd)
4966{
4967	struct ftrace_func_command *p;
4968	int ret = 0;
4969
4970	mutex_lock(&ftrace_cmd_mutex);
4971	list_for_each_entry(p, &ftrace_commands, list) {
4972		if (strcmp(cmd->name, p->name) == 0) {
4973			ret = -EBUSY;
4974			goto out_unlock;
4975		}
4976	}
4977	list_add(&cmd->list, &ftrace_commands);
4978 out_unlock:
4979	mutex_unlock(&ftrace_cmd_mutex);
4980
4981	return ret;
4982}
4983
4984/*
4985 * Currently we only unregister ftrace commands from __init, so mark
4986 * this __init too.
4987 */
4988__init int unregister_ftrace_command(struct ftrace_func_command *cmd)
4989{
4990	struct ftrace_func_command *p, *n;
4991	int ret = -ENODEV;
4992
4993	mutex_lock(&ftrace_cmd_mutex);
4994	list_for_each_entry_safe(p, n, &ftrace_commands, list) {
4995		if (strcmp(cmd->name, p->name) == 0) {
4996			ret = 0;
4997			list_del_init(&p->list);
4998			goto out_unlock;
4999		}
5000	}
5001 out_unlock:
5002	mutex_unlock(&ftrace_cmd_mutex);
5003
5004	return ret;
5005}
5006
5007static int ftrace_process_regex(struct ftrace_iterator *iter,
5008				char *buff, int len, int enable)
5009{
5010	struct ftrace_hash *hash = iter->hash;
5011	struct trace_array *tr = iter->ops->private;
5012	char *func, *command, *next = buff;
5013	struct ftrace_func_command *p;
5014	int ret = -EINVAL;
5015
5016	func = strsep(&next, ":");
5017
5018	if (!next) {
5019		ret = ftrace_match_records(hash, func, len);
5020		if (!ret)
5021			ret = -EINVAL;
5022		if (ret < 0)
5023			return ret;
5024		return 0;
5025	}
5026
5027	/* command found */
5028
5029	command = strsep(&next, ":");
5030
5031	mutex_lock(&ftrace_cmd_mutex);
5032	list_for_each_entry(p, &ftrace_commands, list) {
5033		if (strcmp(p->name, command) == 0) {
5034			ret = p->func(tr, hash, func, command, next, enable);
5035			goto out_unlock;
5036		}
5037	}
5038 out_unlock:
5039	mutex_unlock(&ftrace_cmd_mutex);
5040
5041	return ret;
5042}
5043
5044static ssize_t
5045ftrace_regex_write(struct file *file, const char __user *ubuf,
5046		   size_t cnt, loff_t *ppos, int enable)
5047{
5048	struct ftrace_iterator *iter;
5049	struct trace_parser *parser;
5050	ssize_t ret, read;
5051
5052	if (!cnt)
5053		return 0;
5054
5055	if (file->f_mode & FMODE_READ) {
5056		struct seq_file *m = file->private_data;
5057		iter = m->private;
5058	} else
5059		iter = file->private_data;
5060
5061	if (unlikely(ftrace_disabled))
5062		return -ENODEV;
5063
5064	/* iter->hash is a local copy, so we don't need regex_lock */
5065
5066	parser = &iter->parser;
5067	read = trace_get_user(parser, ubuf, cnt, ppos);
5068
5069	if (read >= 0 && trace_parser_loaded(parser) &&
5070	    !trace_parser_cont(parser)) {
5071		ret = ftrace_process_regex(iter, parser->buffer,
5072					   parser->idx, enable);
5073		trace_parser_clear(parser);
5074		if (ret < 0)
5075			goto out;
5076	}
5077
5078	ret = read;
5079 out:
5080	return ret;
5081}
5082
5083ssize_t
5084ftrace_filter_write(struct file *file, const char __user *ubuf,
5085		    size_t cnt, loff_t *ppos)
5086{
5087	return ftrace_regex_write(file, ubuf, cnt, ppos, 1);
5088}
5089
5090ssize_t
5091ftrace_notrace_write(struct file *file, const char __user *ubuf,
5092		     size_t cnt, loff_t *ppos)
5093{
5094	return ftrace_regex_write(file, ubuf, cnt, ppos, 0);
5095}
5096
5097static int
5098__ftrace_match_addr(struct ftrace_hash *hash, unsigned long ip, int remove)
5099{
5100	struct ftrace_func_entry *entry;
5101
5102	ip = ftrace_location(ip);
5103	if (!ip)
5104		return -EINVAL;
5105
5106	if (remove) {
5107		entry = ftrace_lookup_ip(hash, ip);
5108		if (!entry)
5109			return -ENOENT;
5110		free_hash_entry(hash, entry);
5111		return 0;
5112	}
5113
5114	return add_hash_entry(hash, ip);
5115}
5116
5117static int
5118ftrace_match_addr(struct ftrace_hash *hash, unsigned long *ips,
5119		  unsigned int cnt, int remove)
5120{
5121	unsigned int i;
5122	int err;
5123
5124	for (i = 0; i < cnt; i++) {
5125		err = __ftrace_match_addr(hash, ips[i], remove);
5126		if (err) {
5127			/*
5128			 * This expects the @hash is a temporary hash and if this
5129			 * fails the caller must free the @hash.
5130			 */
5131			return err;
5132		}
5133	}
5134	return 0;
5135}
5136
5137static int
5138ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
5139		unsigned long *ips, unsigned int cnt,
5140		int remove, int reset, int enable)
5141{
5142	struct ftrace_hash **orig_hash;
5143	struct ftrace_hash *hash;
5144	int ret;
5145
5146	if (unlikely(ftrace_disabled))
5147		return -ENODEV;
5148
5149	mutex_lock(&ops->func_hash->regex_lock);
5150
5151	if (enable)
5152		orig_hash = &ops->func_hash->filter_hash;
5153	else
5154		orig_hash = &ops->func_hash->notrace_hash;
5155
5156	if (reset)
5157		hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
5158	else
5159		hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
5160
5161	if (!hash) {
5162		ret = -ENOMEM;
5163		goto out_regex_unlock;
5164	}
5165
5166	if (buf && !ftrace_match_records(hash, buf, len)) {
5167		ret = -EINVAL;
5168		goto out_regex_unlock;
5169	}
5170	if (ips) {
5171		ret = ftrace_match_addr(hash, ips, cnt, remove);
5172		if (ret < 0)
5173			goto out_regex_unlock;
5174	}
5175
5176	mutex_lock(&ftrace_lock);
5177	ret = ftrace_hash_move_and_update_ops(ops, orig_hash, hash, enable);
5178	mutex_unlock(&ftrace_lock);
5179
5180 out_regex_unlock:
5181	mutex_unlock(&ops->func_hash->regex_lock);
5182
5183	free_ftrace_hash(hash);
5184	return ret;
5185}
5186
5187static int
5188ftrace_set_addr(struct ftrace_ops *ops, unsigned long *ips, unsigned int cnt,
5189		int remove, int reset, int enable)
5190{
5191	return ftrace_set_hash(ops, NULL, 0, ips, cnt, remove, reset, enable);
5192}
5193
5194#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
5195
5196struct ftrace_direct_func {
5197	struct list_head	next;
5198	unsigned long		addr;
5199	int			count;
5200};
5201
5202static LIST_HEAD(ftrace_direct_funcs);
5203
5204/**
5205 * ftrace_find_direct_func - test an address if it is a registered direct caller
5206 * @addr: The address of a registered direct caller
5207 *
5208 * This searches to see if a ftrace direct caller has been registered
5209 * at a specific address, and if so, it returns a descriptor for it.
5210 *
5211 * This can be used by architecture code to see if an address is
5212 * a direct caller (trampoline) attached to a fentry/mcount location.
5213 * This is useful for the function_graph tracer, as it may need to
5214 * do adjustments if it traced a location that also has a direct
5215 * trampoline attached to it.
5216 */
5217struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr)
5218{
5219	struct ftrace_direct_func *entry;
5220	bool found = false;
5221
5222	/* May be called by fgraph trampoline (protected by rcu tasks) */
5223	list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) {
5224		if (entry->addr == addr) {
5225			found = true;
5226			break;
5227		}
5228	}
5229	if (found)
5230		return entry;
5231
5232	return NULL;
5233}
5234
5235static struct ftrace_direct_func *ftrace_alloc_direct_func(unsigned long addr)
5236{
5237	struct ftrace_direct_func *direct;
5238
5239	direct = kmalloc(sizeof(*direct), GFP_KERNEL);
5240	if (!direct)
5241		return NULL;
5242	direct->addr = addr;
5243	direct->count = 0;
5244	list_add_rcu(&direct->next, &ftrace_direct_funcs);
5245	ftrace_direct_func_count++;
5246	return direct;
5247}
5248
5249static int register_ftrace_function_nolock(struct ftrace_ops *ops);
5250
5251/**
5252 * register_ftrace_direct - Call a custom trampoline directly
5253 * @ip: The address of the nop at the beginning of a function
5254 * @addr: The address of the trampoline to call at @ip
5255 *
5256 * This is used to connect a direct call from the nop location (@ip)
5257 * at the start of ftrace traced functions. The location that it calls
5258 * (@addr) must be able to handle a direct call, and save the parameters
5259 * of the function being traced, and restore them (or inject new ones
5260 * if needed), before returning.
5261 *
5262 * Returns:
5263 *  0 on success
5264 *  -EBUSY - Another direct function is already attached (there can be only one)
5265 *  -ENODEV - @ip does not point to a ftrace nop location (or not supported)
5266 *  -ENOMEM - There was an allocation failure.
5267 */
5268int register_ftrace_direct(unsigned long ip, unsigned long addr)
5269{
5270	struct ftrace_direct_func *direct;
5271	struct ftrace_func_entry *entry;
5272	struct ftrace_hash *free_hash = NULL;
5273	struct dyn_ftrace *rec;
5274	int ret = -ENODEV;
5275
5276	mutex_lock(&direct_mutex);
5277
5278	ip = ftrace_location(ip);
5279	if (!ip)
5280		goto out_unlock;
5281
5282	/* See if there's a direct function at @ip already */
5283	ret = -EBUSY;
5284	if (ftrace_find_rec_direct(ip))
5285		goto out_unlock;
5286
5287	ret = -ENODEV;
5288	rec = lookup_rec(ip, ip);
5289	if (!rec)
5290		goto out_unlock;
5291
5292	/*
5293	 * Check if the rec says it has a direct call but we didn't
5294	 * find one earlier?
5295	 */
5296	if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
5297		goto out_unlock;
5298
5299	/* Make sure the ip points to the exact record */
5300	if (ip != rec->ip) {
5301		ip = rec->ip;
5302		/* Need to check this ip for a direct. */
5303		if (ftrace_find_rec_direct(ip))
5304			goto out_unlock;
5305	}
5306
5307	ret = -ENOMEM;
5308	direct = ftrace_find_direct_func(addr);
5309	if (!direct) {
5310		direct = ftrace_alloc_direct_func(addr);
5311		if (!direct)
 
 
 
 
 
 
 
5312			goto out_unlock;
 
 
 
5313	}
5314
5315	entry = ftrace_add_rec_direct(ip, addr, &free_hash);
5316	if (!entry)
5317		goto out_unlock;
5318
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5319	ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0);
 
 
5320
5321	if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) {
5322		ret = register_ftrace_function_nolock(&direct_ops);
5323		if (ret)
5324			ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5325	}
5326
5327	if (ret) {
5328		remove_hash_entry(direct_functions, entry);
5329		kfree(entry);
5330		if (!direct->count) {
5331			list_del_rcu(&direct->next);
5332			synchronize_rcu_tasks();
5333			kfree(direct);
5334			if (free_hash)
5335				free_ftrace_hash(free_hash);
5336			free_hash = NULL;
5337			ftrace_direct_func_count--;
5338		}
5339	} else {
5340		direct->count++;
5341	}
5342 out_unlock:
5343	mutex_unlock(&direct_mutex);
5344
5345	if (free_hash) {
5346		synchronize_rcu_tasks();
5347		free_ftrace_hash(free_hash);
5348	}
5349
5350	return ret;
5351}
5352EXPORT_SYMBOL_GPL(register_ftrace_direct);
5353
5354static struct ftrace_func_entry *find_direct_entry(unsigned long *ip,
5355						   struct dyn_ftrace **recp)
5356{
5357	struct ftrace_func_entry *entry;
5358	struct dyn_ftrace *rec;
5359
5360	rec = lookup_rec(*ip, *ip);
5361	if (!rec)
5362		return NULL;
5363
5364	entry = __ftrace_lookup_ip(direct_functions, rec->ip);
5365	if (!entry) {
5366		WARN_ON(rec->flags & FTRACE_FL_DIRECT);
5367		return NULL;
5368	}
5369
5370	WARN_ON(!(rec->flags & FTRACE_FL_DIRECT));
5371
5372	/* Passed in ip just needs to be on the call site */
5373	*ip = rec->ip;
5374
5375	if (recp)
5376		*recp = rec;
5377
5378	return entry;
5379}
5380
5381int unregister_ftrace_direct(unsigned long ip, unsigned long addr)
5382{
5383	struct ftrace_direct_func *direct;
5384	struct ftrace_func_entry *entry;
5385	struct ftrace_hash *hash;
5386	int ret = -ENODEV;
5387
5388	mutex_lock(&direct_mutex);
5389
5390	ip = ftrace_location(ip);
5391	if (!ip)
5392		goto out_unlock;
5393
5394	entry = find_direct_entry(&ip, NULL);
5395	if (!entry)
5396		goto out_unlock;
5397
5398	hash = direct_ops.func_hash->filter_hash;
5399	if (hash->count == 1)
5400		unregister_ftrace_function(&direct_ops);
5401
5402	ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0);
5403
5404	WARN_ON(ret);
5405
5406	remove_hash_entry(direct_functions, entry);
5407
5408	direct = ftrace_find_direct_func(addr);
5409	if (!WARN_ON(!direct)) {
5410		/* This is the good path (see the ! before WARN) */
5411		direct->count--;
5412		WARN_ON(direct->count < 0);
5413		if (!direct->count) {
5414			list_del_rcu(&direct->next);
5415			synchronize_rcu_tasks();
5416			kfree(direct);
5417			kfree(entry);
5418			ftrace_direct_func_count--;
5419		}
5420	}
5421 out_unlock:
5422	mutex_unlock(&direct_mutex);
5423
5424	return ret;
5425}
5426EXPORT_SYMBOL_GPL(unregister_ftrace_direct);
5427
5428static struct ftrace_ops stub_ops = {
5429	.func		= ftrace_stub,
5430};
5431
5432/**
5433 * ftrace_modify_direct_caller - modify ftrace nop directly
5434 * @entry: The ftrace hash entry of the direct helper for @rec
5435 * @rec: The record representing the function site to patch
5436 * @old_addr: The location that the site at @rec->ip currently calls
5437 * @new_addr: The location that the site at @rec->ip should call
5438 *
5439 * An architecture may overwrite this function to optimize the
5440 * changing of the direct callback on an ftrace nop location.
5441 * This is called with the ftrace_lock mutex held, and no other
5442 * ftrace callbacks are on the associated record (@rec). Thus,
5443 * it is safe to modify the ftrace record, where it should be
5444 * currently calling @old_addr directly, to call @new_addr.
5445 *
5446 * This is called with direct_mutex locked.
5447 *
5448 * Safety checks should be made to make sure that the code at
5449 * @rec->ip is currently calling @old_addr. And this must
5450 * also update entry->direct to @new_addr.
5451 */
5452int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry,
5453				       struct dyn_ftrace *rec,
5454				       unsigned long old_addr,
5455				       unsigned long new_addr)
5456{
5457	unsigned long ip = rec->ip;
5458	int ret;
5459
5460	lockdep_assert_held(&direct_mutex);
5461
5462	/*
5463	 * The ftrace_lock was used to determine if the record
5464	 * had more than one registered user to it. If it did,
5465	 * we needed to prevent that from changing to do the quick
5466	 * switch. But if it did not (only a direct caller was attached)
5467	 * then this function is called. But this function can deal
5468	 * with attached callers to the rec that we care about, and
5469	 * since this function uses standard ftrace calls that take
5470	 * the ftrace_lock mutex, we need to release it.
5471	 */
5472	mutex_unlock(&ftrace_lock);
5473
5474	/*
5475	 * By setting a stub function at the same address, we force
5476	 * the code to call the iterator and the direct_ops helper.
5477	 * This means that @ip does not call the direct call, and
5478	 * we can simply modify it.
5479	 */
5480	ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0);
5481	if (ret)
5482		goto out_lock;
5483
5484	ret = register_ftrace_function_nolock(&stub_ops);
5485	if (ret) {
5486		ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5487		goto out_lock;
5488	}
5489
5490	entry->direct = new_addr;
5491
5492	/*
5493	 * By removing the stub, we put back the direct call, calling
5494	 * the @new_addr.
5495	 */
5496	unregister_ftrace_function(&stub_ops);
5497	ftrace_set_filter_ip(&stub_ops, ip, 1, 0);
5498
5499 out_lock:
5500	mutex_lock(&ftrace_lock);
5501
5502	return ret;
5503}
5504
5505/**
5506 * modify_ftrace_direct - Modify an existing direct call to call something else
5507 * @ip: The instruction pointer to modify
5508 * @old_addr: The address that the current @ip calls directly
5509 * @new_addr: The address that the @ip should call
5510 *
5511 * This modifies a ftrace direct caller at an instruction pointer without
5512 * having to disable it first. The direct call will switch over to the
5513 * @new_addr without missing anything.
5514 *
5515 * Returns: zero on success. Non zero on error, which includes:
5516 *  -ENODEV : the @ip given has no direct caller attached
5517 *  -EINVAL : the @old_addr does not match the current direct caller
5518 */
5519int modify_ftrace_direct(unsigned long ip,
5520			 unsigned long old_addr, unsigned long new_addr)
5521{
5522	struct ftrace_direct_func *direct, *new_direct = NULL;
5523	struct ftrace_func_entry *entry;
5524	struct dyn_ftrace *rec;
5525	int ret = -ENODEV;
5526
5527	mutex_lock(&direct_mutex);
5528
5529	mutex_lock(&ftrace_lock);
5530
5531	ip = ftrace_location(ip);
5532	if (!ip)
5533		goto out_unlock;
5534
5535	entry = find_direct_entry(&ip, &rec);
5536	if (!entry)
5537		goto out_unlock;
5538
5539	ret = -EINVAL;
5540	if (entry->direct != old_addr)
5541		goto out_unlock;
5542
5543	direct = ftrace_find_direct_func(old_addr);
5544	if (WARN_ON(!direct))
5545		goto out_unlock;
5546	if (direct->count > 1) {
5547		ret = -ENOMEM;
5548		new_direct = ftrace_alloc_direct_func(new_addr);
5549		if (!new_direct)
5550			goto out_unlock;
5551		direct->count--;
5552		new_direct->count++;
5553	} else {
5554		direct->addr = new_addr;
5555	}
5556
5557	/*
5558	 * If there's no other ftrace callback on the rec->ip location,
5559	 * then it can be changed directly by the architecture.
5560	 * If there is another caller, then we just need to change the
5561	 * direct caller helper to point to @new_addr.
5562	 */
5563	if (ftrace_rec_count(rec) == 1) {
5564		ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr);
5565	} else {
5566		entry->direct = new_addr;
5567		ret = 0;
5568	}
5569
5570	if (unlikely(ret && new_direct)) {
5571		direct->count++;
5572		list_del_rcu(&new_direct->next);
5573		synchronize_rcu_tasks();
5574		kfree(new_direct);
5575		ftrace_direct_func_count--;
5576	}
5577
5578 out_unlock:
5579	mutex_unlock(&ftrace_lock);
5580	mutex_unlock(&direct_mutex);
5581	return ret;
5582}
5583EXPORT_SYMBOL_GPL(modify_ftrace_direct);
5584
5585#define MULTI_FLAGS (FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS)
5586
5587static int check_direct_multi(struct ftrace_ops *ops)
5588{
5589	if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5590		return -EINVAL;
5591	if ((ops->flags & MULTI_FLAGS) != MULTI_FLAGS)
5592		return -EINVAL;
5593	return 0;
5594}
5595
5596static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long addr)
5597{
5598	struct ftrace_func_entry *entry, *del;
5599	int size, i;
5600
5601	size = 1 << hash->size_bits;
5602	for (i = 0; i < size; i++) {
5603		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5604			del = __ftrace_lookup_ip(direct_functions, entry->ip);
5605			if (del && del->direct == addr) {
5606				remove_hash_entry(direct_functions, del);
5607				kfree(del);
5608			}
5609		}
5610	}
5611}
5612
5613/**
5614 * register_ftrace_direct_multi - Call a custom trampoline directly
5615 * for multiple functions registered in @ops
5616 * @ops: The address of the struct ftrace_ops object
5617 * @addr: The address of the trampoline to call at @ops functions
5618 *
5619 * This is used to connect a direct calls to @addr from the nop locations
5620 * of the functions registered in @ops (with by ftrace_set_filter_ip
5621 * function).
5622 *
5623 * The location that it calls (@addr) must be able to handle a direct call,
5624 * and save the parameters of the function being traced, and restore them
5625 * (or inject new ones if needed), before returning.
5626 *
5627 * Returns:
5628 *  0 on success
5629 *  -EINVAL  - The @ops object was already registered with this call or
5630 *             when there are no functions in @ops object.
5631 *  -EBUSY   - Another direct function is already attached (there can be only one)
5632 *  -ENODEV  - @ip does not point to a ftrace nop location (or not supported)
5633 *  -ENOMEM  - There was an allocation failure.
5634 */
5635int register_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5636{
5637	struct ftrace_hash *hash, *free_hash = NULL;
5638	struct ftrace_func_entry *entry, *new;
5639	int err = -EBUSY, size, i;
5640
5641	if (ops->func || ops->trampoline)
5642		return -EINVAL;
5643	if (!(ops->flags & FTRACE_OPS_FL_INITIALIZED))
5644		return -EINVAL;
5645	if (ops->flags & FTRACE_OPS_FL_ENABLED)
5646		return -EINVAL;
5647
5648	hash = ops->func_hash->filter_hash;
5649	if (ftrace_hash_empty(hash))
5650		return -EINVAL;
5651
5652	mutex_lock(&direct_mutex);
5653
5654	/* Make sure requested entries are not already registered.. */
5655	size = 1 << hash->size_bits;
5656	for (i = 0; i < size; i++) {
5657		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5658			if (ftrace_find_rec_direct(entry->ip))
5659				goto out_unlock;
5660		}
5661	}
5662
5663	/* ... and insert them to direct_functions hash. */
5664	err = -ENOMEM;
5665	for (i = 0; i < size; i++) {
5666		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
5667			new = ftrace_add_rec_direct(entry->ip, addr, &free_hash);
5668			if (!new)
5669				goto out_remove;
5670			entry->direct = addr;
5671		}
5672	}
5673
5674	ops->func = call_direct_funcs;
5675	ops->flags = MULTI_FLAGS;
5676	ops->trampoline = FTRACE_REGS_ADDR;
5677
5678	err = register_ftrace_function_nolock(ops);
5679
5680 out_remove:
5681	if (err)
5682		remove_direct_functions_hash(hash, addr);
5683
5684 out_unlock:
5685	mutex_unlock(&direct_mutex);
5686
5687	if (free_hash) {
5688		synchronize_rcu_tasks();
5689		free_ftrace_hash(free_hash);
5690	}
5691	return err;
5692}
5693EXPORT_SYMBOL_GPL(register_ftrace_direct_multi);
5694
5695/**
5696 * unregister_ftrace_direct_multi - Remove calls to custom trampoline
5697 * previously registered by register_ftrace_direct_multi for @ops object.
5698 * @ops: The address of the struct ftrace_ops object
5699 *
5700 * This is used to remove a direct calls to @addr from the nop locations
5701 * of the functions registered in @ops (with by ftrace_set_filter_ip
5702 * function).
5703 *
5704 * Returns:
5705 *  0 on success
5706 *  -EINVAL - The @ops object was not properly registered.
5707 */
5708int unregister_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5709{
5710	struct ftrace_hash *hash = ops->func_hash->filter_hash;
5711	int err;
5712
5713	if (check_direct_multi(ops))
5714		return -EINVAL;
5715	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5716		return -EINVAL;
5717
5718	mutex_lock(&direct_mutex);
5719	err = unregister_ftrace_function(ops);
5720	remove_direct_functions_hash(hash, addr);
5721	mutex_unlock(&direct_mutex);
5722
5723	/* cleanup for possible another register call */
5724	ops->func = NULL;
5725	ops->trampoline = 0;
5726	return err;
5727}
5728EXPORT_SYMBOL_GPL(unregister_ftrace_direct_multi);
5729
5730static int
5731__modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5732{
5733	struct ftrace_hash *hash;
5734	struct ftrace_func_entry *entry, *iter;
5735	static struct ftrace_ops tmp_ops = {
5736		.func		= ftrace_stub,
5737		.flags		= FTRACE_OPS_FL_STUB,
5738	};
5739	int i, size;
5740	int err;
5741
5742	lockdep_assert_held_once(&direct_mutex);
5743
5744	/* Enable the tmp_ops to have the same functions as the direct ops */
5745	ftrace_ops_init(&tmp_ops);
5746	tmp_ops.func_hash = ops->func_hash;
5747
5748	err = register_ftrace_function_nolock(&tmp_ops);
5749	if (err)
5750		return err;
5751
5752	/*
5753	 * Now the ftrace_ops_list_func() is called to do the direct callers.
5754	 * We can safely change the direct functions attached to each entry.
5755	 */
5756	mutex_lock(&ftrace_lock);
5757
5758	hash = ops->func_hash->filter_hash;
5759	size = 1 << hash->size_bits;
5760	for (i = 0; i < size; i++) {
5761		hlist_for_each_entry(iter, &hash->buckets[i], hlist) {
5762			entry = __ftrace_lookup_ip(direct_functions, iter->ip);
5763			if (!entry)
5764				continue;
5765			entry->direct = addr;
5766		}
5767	}
5768
5769	mutex_unlock(&ftrace_lock);
5770
5771	/* Removing the tmp_ops will add the updated direct callers to the functions */
5772	unregister_ftrace_function(&tmp_ops);
5773
5774	return err;
5775}
5776
5777/**
5778 * modify_ftrace_direct_multi_nolock - Modify an existing direct 'multi' call
5779 * to call something else
5780 * @ops: The address of the struct ftrace_ops object
5781 * @addr: The address of the new trampoline to call at @ops functions
5782 *
5783 * This is used to unregister currently registered direct caller and
5784 * register new one @addr on functions registered in @ops object.
5785 *
5786 * Note there's window between ftrace_shutdown and ftrace_startup calls
5787 * where there will be no callbacks called.
5788 *
5789 * Caller should already have direct_mutex locked, so we don't lock
5790 * direct_mutex here.
5791 *
5792 * Returns: zero on success. Non zero on error, which includes:
5793 *  -EINVAL - The @ops object was not properly registered.
5794 */
5795int modify_ftrace_direct_multi_nolock(struct ftrace_ops *ops, unsigned long addr)
5796{
5797	if (check_direct_multi(ops))
5798		return -EINVAL;
5799	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5800		return -EINVAL;
5801
5802	return __modify_ftrace_direct_multi(ops, addr);
5803}
5804EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi_nolock);
5805
5806/**
5807 * modify_ftrace_direct_multi - Modify an existing direct 'multi' call
5808 * to call something else
5809 * @ops: The address of the struct ftrace_ops object
5810 * @addr: The address of the new trampoline to call at @ops functions
5811 *
5812 * This is used to unregister currently registered direct caller and
5813 * register new one @addr on functions registered in @ops object.
5814 *
5815 * Note there's window between ftrace_shutdown and ftrace_startup calls
5816 * where there will be no callbacks called.
5817 *
5818 * Returns: zero on success. Non zero on error, which includes:
5819 *  -EINVAL - The @ops object was not properly registered.
5820 */
5821int modify_ftrace_direct_multi(struct ftrace_ops *ops, unsigned long addr)
5822{
5823	int err;
5824
5825	if (check_direct_multi(ops))
5826		return -EINVAL;
5827	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
5828		return -EINVAL;
5829
5830	mutex_lock(&direct_mutex);
5831	err = __modify_ftrace_direct_multi(ops, addr);
5832	mutex_unlock(&direct_mutex);
5833	return err;
5834}
5835EXPORT_SYMBOL_GPL(modify_ftrace_direct_multi);
5836#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
5837
5838/**
5839 * ftrace_set_filter_ip - set a function to filter on in ftrace by address
5840 * @ops - the ops to set the filter with
5841 * @ip - the address to add to or remove from the filter.
5842 * @remove - non zero to remove the ip from the filter
5843 * @reset - non zero to reset all filters before applying this filter.
5844 *
5845 * Filters denote which functions should be enabled when tracing is enabled
5846 * If @ip is NULL, it fails to update filter.
5847 *
5848 * This can allocate memory which must be freed before @ops can be freed,
5849 * either by removing each filtered addr or by using
5850 * ftrace_free_filter(@ops).
5851 */
5852int ftrace_set_filter_ip(struct ftrace_ops *ops, unsigned long ip,
5853			 int remove, int reset)
5854{
5855	ftrace_ops_init(ops);
5856	return ftrace_set_addr(ops, &ip, 1, remove, reset, 1);
5857}
5858EXPORT_SYMBOL_GPL(ftrace_set_filter_ip);
5859
5860/**
5861 * ftrace_set_filter_ips - set functions to filter on in ftrace by addresses
5862 * @ops - the ops to set the filter with
5863 * @ips - the array of addresses to add to or remove from the filter.
5864 * @cnt - the number of addresses in @ips
5865 * @remove - non zero to remove ips from the filter
5866 * @reset - non zero to reset all filters before applying this filter.
5867 *
5868 * Filters denote which functions should be enabled when tracing is enabled
5869 * If @ips array or any ip specified within is NULL , it fails to update filter.
5870 *
5871 * This can allocate memory which must be freed before @ops can be freed,
5872 * either by removing each filtered addr or by using
5873 * ftrace_free_filter(@ops).
5874*/
5875int ftrace_set_filter_ips(struct ftrace_ops *ops, unsigned long *ips,
5876			  unsigned int cnt, int remove, int reset)
5877{
5878	ftrace_ops_init(ops);
5879	return ftrace_set_addr(ops, ips, cnt, remove, reset, 1);
5880}
5881EXPORT_SYMBOL_GPL(ftrace_set_filter_ips);
5882
5883/**
5884 * ftrace_ops_set_global_filter - setup ops to use global filters
5885 * @ops - the ops which will use the global filters
5886 *
5887 * ftrace users who need global function trace filtering should call this.
5888 * It can set the global filter only if ops were not initialized before.
5889 */
5890void ftrace_ops_set_global_filter(struct ftrace_ops *ops)
5891{
5892	if (ops->flags & FTRACE_OPS_FL_INITIALIZED)
5893		return;
5894
5895	ftrace_ops_init(ops);
5896	ops->func_hash = &global_ops.local_hash;
5897}
5898EXPORT_SYMBOL_GPL(ftrace_ops_set_global_filter);
5899
5900static int
5901ftrace_set_regex(struct ftrace_ops *ops, unsigned char *buf, int len,
5902		 int reset, int enable)
5903{
5904	return ftrace_set_hash(ops, buf, len, NULL, 0, 0, reset, enable);
5905}
5906
5907/**
5908 * ftrace_set_filter - set a function to filter on in ftrace
5909 * @ops - the ops to set the filter with
5910 * @buf - the string that holds the function filter text.
5911 * @len - the length of the string.
5912 * @reset - non zero to reset all filters before applying this filter.
5913 *
5914 * Filters denote which functions should be enabled when tracing is enabled.
5915 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5916 *
5917 * This can allocate memory which must be freed before @ops can be freed,
5918 * either by removing each filtered addr or by using
5919 * ftrace_free_filter(@ops).
5920 */
5921int ftrace_set_filter(struct ftrace_ops *ops, unsigned char *buf,
5922		       int len, int reset)
5923{
5924	ftrace_ops_init(ops);
5925	return ftrace_set_regex(ops, buf, len, reset, 1);
5926}
5927EXPORT_SYMBOL_GPL(ftrace_set_filter);
5928
5929/**
5930 * ftrace_set_notrace - set a function to not trace in ftrace
5931 * @ops - the ops to set the notrace filter with
5932 * @buf - the string that holds the function notrace text.
5933 * @len - the length of the string.
5934 * @reset - non zero to reset all filters before applying this filter.
5935 *
5936 * Notrace Filters denote which functions should not be enabled when tracing
5937 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5938 * for tracing.
5939 *
5940 * This can allocate memory which must be freed before @ops can be freed,
5941 * either by removing each filtered addr or by using
5942 * ftrace_free_filter(@ops).
5943 */
5944int ftrace_set_notrace(struct ftrace_ops *ops, unsigned char *buf,
5945			int len, int reset)
5946{
5947	ftrace_ops_init(ops);
5948	return ftrace_set_regex(ops, buf, len, reset, 0);
5949}
5950EXPORT_SYMBOL_GPL(ftrace_set_notrace);
5951/**
5952 * ftrace_set_global_filter - set a function to filter on with global tracers
5953 * @buf - the string that holds the function filter text.
5954 * @len - the length of the string.
5955 * @reset - non zero to reset all filters before applying this filter.
5956 *
5957 * Filters denote which functions should be enabled when tracing is enabled.
5958 * If @buf is NULL and reset is set, all functions will be enabled for tracing.
5959 */
5960void ftrace_set_global_filter(unsigned char *buf, int len, int reset)
5961{
5962	ftrace_set_regex(&global_ops, buf, len, reset, 1);
5963}
5964EXPORT_SYMBOL_GPL(ftrace_set_global_filter);
5965
5966/**
5967 * ftrace_set_global_notrace - set a function to not trace with global tracers
5968 * @buf - the string that holds the function notrace text.
5969 * @len - the length of the string.
5970 * @reset - non zero to reset all filters before applying this filter.
5971 *
5972 * Notrace Filters denote which functions should not be enabled when tracing
5973 * is enabled. If @buf is NULL and reset is set, all functions will be enabled
5974 * for tracing.
5975 */
5976void ftrace_set_global_notrace(unsigned char *buf, int len, int reset)
5977{
5978	ftrace_set_regex(&global_ops, buf, len, reset, 0);
5979}
5980EXPORT_SYMBOL_GPL(ftrace_set_global_notrace);
5981
5982/*
5983 * command line interface to allow users to set filters on boot up.
5984 */
5985#define FTRACE_FILTER_SIZE		COMMAND_LINE_SIZE
5986static char ftrace_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
5987static char ftrace_filter_buf[FTRACE_FILTER_SIZE] __initdata;
5988
5989/* Used by function selftest to not test if filter is set */
5990bool ftrace_filter_param __initdata;
5991
5992static int __init set_ftrace_notrace(char *str)
5993{
5994	ftrace_filter_param = true;
5995	strlcpy(ftrace_notrace_buf, str, FTRACE_FILTER_SIZE);
5996	return 1;
5997}
5998__setup("ftrace_notrace=", set_ftrace_notrace);
5999
6000static int __init set_ftrace_filter(char *str)
6001{
6002	ftrace_filter_param = true;
6003	strlcpy(ftrace_filter_buf, str, FTRACE_FILTER_SIZE);
6004	return 1;
6005}
6006__setup("ftrace_filter=", set_ftrace_filter);
6007
6008#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6009static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata;
6010static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata;
6011static int ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer);
6012
6013static int __init set_graph_function(char *str)
6014{
6015	strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE);
6016	return 1;
6017}
6018__setup("ftrace_graph_filter=", set_graph_function);
6019
6020static int __init set_graph_notrace_function(char *str)
6021{
6022	strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE);
6023	return 1;
6024}
6025__setup("ftrace_graph_notrace=", set_graph_notrace_function);
6026
6027static int __init set_graph_max_depth_function(char *str)
6028{
6029	if (!str)
6030		return 0;
6031	fgraph_max_depth = simple_strtoul(str, NULL, 0);
6032	return 1;
6033}
6034__setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
6035
6036static void __init set_ftrace_early_graph(char *buf, int enable)
6037{
6038	int ret;
6039	char *func;
6040	struct ftrace_hash *hash;
6041
6042	hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
6043	if (MEM_FAIL(!hash, "Failed to allocate hash\n"))
6044		return;
6045
6046	while (buf) {
6047		func = strsep(&buf, ",");
6048		/* we allow only one expression at a time */
6049		ret = ftrace_graph_set_hash(hash, func);
6050		if (ret)
6051			printk(KERN_DEBUG "ftrace: function %s not "
6052					  "traceable\n", func);
6053	}
6054
6055	if (enable)
6056		ftrace_graph_hash = hash;
6057	else
6058		ftrace_graph_notrace_hash = hash;
6059}
6060#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6061
6062void __init
6063ftrace_set_early_filter(struct ftrace_ops *ops, char *buf, int enable)
6064{
6065	char *func;
6066
6067	ftrace_ops_init(ops);
6068
6069	while (buf) {
6070		func = strsep(&buf, ",");
6071		ftrace_set_regex(ops, func, strlen(func), 0, enable);
6072	}
6073}
6074
6075static void __init set_ftrace_early_filters(void)
6076{
6077	if (ftrace_filter_buf[0])
6078		ftrace_set_early_filter(&global_ops, ftrace_filter_buf, 1);
6079	if (ftrace_notrace_buf[0])
6080		ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0);
6081#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6082	if (ftrace_graph_buf[0])
6083		set_ftrace_early_graph(ftrace_graph_buf, 1);
6084	if (ftrace_graph_notrace_buf[0])
6085		set_ftrace_early_graph(ftrace_graph_notrace_buf, 0);
6086#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6087}
6088
6089int ftrace_regex_release(struct inode *inode, struct file *file)
6090{
6091	struct seq_file *m = (struct seq_file *)file->private_data;
6092	struct ftrace_iterator *iter;
6093	struct ftrace_hash **orig_hash;
6094	struct trace_parser *parser;
6095	int filter_hash;
 
6096
6097	if (file->f_mode & FMODE_READ) {
6098		iter = m->private;
6099		seq_release(inode, file);
6100	} else
6101		iter = file->private_data;
6102
6103	parser = &iter->parser;
6104	if (trace_parser_loaded(parser)) {
6105		int enable = !(iter->flags & FTRACE_ITER_NOTRACE);
6106
6107		ftrace_process_regex(iter, parser->buffer,
6108				     parser->idx, enable);
6109	}
6110
6111	trace_parser_put(parser);
6112
6113	mutex_lock(&iter->ops->func_hash->regex_lock);
6114
6115	if (file->f_mode & FMODE_WRITE) {
6116		filter_hash = !!(iter->flags & FTRACE_ITER_FILTER);
6117
6118		if (filter_hash) {
6119			orig_hash = &iter->ops->func_hash->filter_hash;
6120			if (iter->tr) {
6121				if (list_empty(&iter->tr->mod_trace))
6122					iter->hash->flags &= ~FTRACE_HASH_FL_MOD;
6123				else
6124					iter->hash->flags |= FTRACE_HASH_FL_MOD;
6125			}
6126		} else
6127			orig_hash = &iter->ops->func_hash->notrace_hash;
6128
6129		mutex_lock(&ftrace_lock);
6130		ftrace_hash_move_and_update_ops(iter->ops, orig_hash,
6131						      iter->hash, filter_hash);
6132		mutex_unlock(&ftrace_lock);
6133	} else {
6134		/* For read only, the hash is the ops hash */
6135		iter->hash = NULL;
6136	}
6137
6138	mutex_unlock(&iter->ops->func_hash->regex_lock);
6139	free_ftrace_hash(iter->hash);
6140	if (iter->tr)
6141		trace_array_put(iter->tr);
6142	kfree(iter);
6143
6144	return 0;
6145}
6146
6147static const struct file_operations ftrace_avail_fops = {
6148	.open = ftrace_avail_open,
6149	.read = seq_read,
6150	.llseek = seq_lseek,
6151	.release = seq_release_private,
6152};
6153
6154static const struct file_operations ftrace_enabled_fops = {
6155	.open = ftrace_enabled_open,
6156	.read = seq_read,
6157	.llseek = seq_lseek,
6158	.release = seq_release_private,
6159};
6160
6161static const struct file_operations ftrace_filter_fops = {
6162	.open = ftrace_filter_open,
6163	.read = seq_read,
6164	.write = ftrace_filter_write,
6165	.llseek = tracing_lseek,
6166	.release = ftrace_regex_release,
6167};
6168
6169static const struct file_operations ftrace_notrace_fops = {
6170	.open = ftrace_notrace_open,
6171	.read = seq_read,
6172	.write = ftrace_notrace_write,
6173	.llseek = tracing_lseek,
6174	.release = ftrace_regex_release,
6175};
6176
6177#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6178
6179static DEFINE_MUTEX(graph_lock);
6180
6181struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
6182struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH;
6183
6184enum graph_filter_type {
6185	GRAPH_FILTER_NOTRACE	= 0,
6186	GRAPH_FILTER_FUNCTION,
6187};
6188
6189#define FTRACE_GRAPH_EMPTY	((void *)1)
6190
6191struct ftrace_graph_data {
6192	struct ftrace_hash		*hash;
6193	struct ftrace_func_entry	*entry;
6194	int				idx;   /* for hash table iteration */
6195	enum graph_filter_type		type;
6196	struct ftrace_hash		*new_hash;
6197	const struct seq_operations	*seq_ops;
6198	struct trace_parser		parser;
6199};
6200
6201static void *
6202__g_next(struct seq_file *m, loff_t *pos)
6203{
6204	struct ftrace_graph_data *fgd = m->private;
6205	struct ftrace_func_entry *entry = fgd->entry;
6206	struct hlist_head *head;
6207	int i, idx = fgd->idx;
6208
6209	if (*pos >= fgd->hash->count)
6210		return NULL;
6211
6212	if (entry) {
6213		hlist_for_each_entry_continue(entry, hlist) {
6214			fgd->entry = entry;
6215			return entry;
6216		}
6217
6218		idx++;
6219	}
6220
6221	for (i = idx; i < 1 << fgd->hash->size_bits; i++) {
6222		head = &fgd->hash->buckets[i];
6223		hlist_for_each_entry(entry, head, hlist) {
6224			fgd->entry = entry;
6225			fgd->idx = i;
6226			return entry;
6227		}
6228	}
6229	return NULL;
6230}
6231
6232static void *
6233g_next(struct seq_file *m, void *v, loff_t *pos)
6234{
6235	(*pos)++;
6236	return __g_next(m, pos);
6237}
6238
6239static void *g_start(struct seq_file *m, loff_t *pos)
6240{
6241	struct ftrace_graph_data *fgd = m->private;
6242
6243	mutex_lock(&graph_lock);
6244
6245	if (fgd->type == GRAPH_FILTER_FUNCTION)
6246		fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6247					lockdep_is_held(&graph_lock));
6248	else
6249		fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6250					lockdep_is_held(&graph_lock));
6251
6252	/* Nothing, tell g_show to print all functions are enabled */
6253	if (ftrace_hash_empty(fgd->hash) && !*pos)
6254		return FTRACE_GRAPH_EMPTY;
6255
6256	fgd->idx = 0;
6257	fgd->entry = NULL;
6258	return __g_next(m, pos);
6259}
6260
6261static void g_stop(struct seq_file *m, void *p)
6262{
6263	mutex_unlock(&graph_lock);
6264}
6265
6266static int g_show(struct seq_file *m, void *v)
6267{
6268	struct ftrace_func_entry *entry = v;
6269
6270	if (!entry)
6271		return 0;
6272
6273	if (entry == FTRACE_GRAPH_EMPTY) {
6274		struct ftrace_graph_data *fgd = m->private;
6275
6276		if (fgd->type == GRAPH_FILTER_FUNCTION)
6277			seq_puts(m, "#### all functions enabled ####\n");
6278		else
6279			seq_puts(m, "#### no functions disabled ####\n");
6280		return 0;
6281	}
6282
6283	seq_printf(m, "%ps\n", (void *)entry->ip);
6284
6285	return 0;
6286}
6287
6288static const struct seq_operations ftrace_graph_seq_ops = {
6289	.start = g_start,
6290	.next = g_next,
6291	.stop = g_stop,
6292	.show = g_show,
6293};
6294
6295static int
6296__ftrace_graph_open(struct inode *inode, struct file *file,
6297		    struct ftrace_graph_data *fgd)
6298{
6299	int ret;
6300	struct ftrace_hash *new_hash = NULL;
6301
6302	ret = security_locked_down(LOCKDOWN_TRACEFS);
6303	if (ret)
6304		return ret;
6305
6306	if (file->f_mode & FMODE_WRITE) {
6307		const int size_bits = FTRACE_HASH_DEFAULT_BITS;
6308
6309		if (trace_parser_get_init(&fgd->parser, FTRACE_BUFF_MAX))
6310			return -ENOMEM;
6311
6312		if (file->f_flags & O_TRUNC)
6313			new_hash = alloc_ftrace_hash(size_bits);
6314		else
6315			new_hash = alloc_and_copy_ftrace_hash(size_bits,
6316							      fgd->hash);
6317		if (!new_hash) {
6318			ret = -ENOMEM;
6319			goto out;
6320		}
6321	}
6322
6323	if (file->f_mode & FMODE_READ) {
6324		ret = seq_open(file, &ftrace_graph_seq_ops);
6325		if (!ret) {
6326			struct seq_file *m = file->private_data;
6327			m->private = fgd;
6328		} else {
6329			/* Failed */
6330			free_ftrace_hash(new_hash);
6331			new_hash = NULL;
6332		}
6333	} else
6334		file->private_data = fgd;
6335
6336out:
6337	if (ret < 0 && file->f_mode & FMODE_WRITE)
6338		trace_parser_put(&fgd->parser);
6339
6340	fgd->new_hash = new_hash;
6341
6342	/*
6343	 * All uses of fgd->hash must be taken with the graph_lock
6344	 * held. The graph_lock is going to be released, so force
6345	 * fgd->hash to be reinitialized when it is taken again.
6346	 */
6347	fgd->hash = NULL;
6348
6349	return ret;
6350}
6351
6352static int
6353ftrace_graph_open(struct inode *inode, struct file *file)
6354{
6355	struct ftrace_graph_data *fgd;
6356	int ret;
6357
6358	if (unlikely(ftrace_disabled))
6359		return -ENODEV;
6360
6361	fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6362	if (fgd == NULL)
6363		return -ENOMEM;
6364
6365	mutex_lock(&graph_lock);
6366
6367	fgd->hash = rcu_dereference_protected(ftrace_graph_hash,
6368					lockdep_is_held(&graph_lock));
6369	fgd->type = GRAPH_FILTER_FUNCTION;
6370	fgd->seq_ops = &ftrace_graph_seq_ops;
6371
6372	ret = __ftrace_graph_open(inode, file, fgd);
6373	if (ret < 0)
6374		kfree(fgd);
6375
6376	mutex_unlock(&graph_lock);
6377	return ret;
6378}
6379
6380static int
6381ftrace_graph_notrace_open(struct inode *inode, struct file *file)
6382{
6383	struct ftrace_graph_data *fgd;
6384	int ret;
6385
6386	if (unlikely(ftrace_disabled))
6387		return -ENODEV;
6388
6389	fgd = kmalloc(sizeof(*fgd), GFP_KERNEL);
6390	if (fgd == NULL)
6391		return -ENOMEM;
6392
6393	mutex_lock(&graph_lock);
6394
6395	fgd->hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6396					lockdep_is_held(&graph_lock));
6397	fgd->type = GRAPH_FILTER_NOTRACE;
6398	fgd->seq_ops = &ftrace_graph_seq_ops;
6399
6400	ret = __ftrace_graph_open(inode, file, fgd);
6401	if (ret < 0)
6402		kfree(fgd);
6403
6404	mutex_unlock(&graph_lock);
6405	return ret;
6406}
6407
6408static int
6409ftrace_graph_release(struct inode *inode, struct file *file)
6410{
6411	struct ftrace_graph_data *fgd;
6412	struct ftrace_hash *old_hash, *new_hash;
6413	struct trace_parser *parser;
6414	int ret = 0;
6415
6416	if (file->f_mode & FMODE_READ) {
6417		struct seq_file *m = file->private_data;
6418
6419		fgd = m->private;
6420		seq_release(inode, file);
6421	} else {
6422		fgd = file->private_data;
6423	}
6424
6425
6426	if (file->f_mode & FMODE_WRITE) {
6427
6428		parser = &fgd->parser;
6429
6430		if (trace_parser_loaded((parser))) {
6431			ret = ftrace_graph_set_hash(fgd->new_hash,
6432						    parser->buffer);
6433		}
6434
6435		trace_parser_put(parser);
6436
6437		new_hash = __ftrace_hash_move(fgd->new_hash);
6438		if (!new_hash) {
6439			ret = -ENOMEM;
6440			goto out;
6441		}
6442
6443		mutex_lock(&graph_lock);
6444
6445		if (fgd->type == GRAPH_FILTER_FUNCTION) {
6446			old_hash = rcu_dereference_protected(ftrace_graph_hash,
6447					lockdep_is_held(&graph_lock));
6448			rcu_assign_pointer(ftrace_graph_hash, new_hash);
6449		} else {
6450			old_hash = rcu_dereference_protected(ftrace_graph_notrace_hash,
6451					lockdep_is_held(&graph_lock));
6452			rcu_assign_pointer(ftrace_graph_notrace_hash, new_hash);
6453		}
6454
6455		mutex_unlock(&graph_lock);
6456
6457		/*
6458		 * We need to do a hard force of sched synchronization.
6459		 * This is because we use preempt_disable() to do RCU, but
6460		 * the function tracers can be called where RCU is not watching
6461		 * (like before user_exit()). We can not rely on the RCU
6462		 * infrastructure to do the synchronization, thus we must do it
6463		 * ourselves.
6464		 */
6465		if (old_hash != EMPTY_HASH)
6466			synchronize_rcu_tasks_rude();
6467
6468		free_ftrace_hash(old_hash);
6469	}
6470
6471 out:
6472	free_ftrace_hash(fgd->new_hash);
6473	kfree(fgd);
6474
6475	return ret;
6476}
6477
6478static int
6479ftrace_graph_set_hash(struct ftrace_hash *hash, char *buffer)
6480{
6481	struct ftrace_glob func_g;
6482	struct dyn_ftrace *rec;
6483	struct ftrace_page *pg;
6484	struct ftrace_func_entry *entry;
6485	int fail = 1;
6486	int not;
6487
6488	/* decode regex */
6489	func_g.type = filter_parse_regex(buffer, strlen(buffer),
6490					 &func_g.search, &not);
6491
6492	func_g.len = strlen(func_g.search);
6493
6494	mutex_lock(&ftrace_lock);
6495
6496	if (unlikely(ftrace_disabled)) {
6497		mutex_unlock(&ftrace_lock);
6498		return -ENODEV;
6499	}
6500
6501	do_for_each_ftrace_rec(pg, rec) {
6502
6503		if (rec->flags & FTRACE_FL_DISABLED)
6504			continue;
6505
6506		if (ftrace_match_record(rec, &func_g, NULL, 0)) {
6507			entry = ftrace_lookup_ip(hash, rec->ip);
6508
6509			if (!not) {
6510				fail = 0;
6511
6512				if (entry)
6513					continue;
6514				if (add_hash_entry(hash, rec->ip) < 0)
6515					goto out;
6516			} else {
6517				if (entry) {
6518					free_hash_entry(hash, entry);
6519					fail = 0;
6520				}
6521			}
6522		}
6523	} while_for_each_ftrace_rec();
6524out:
6525	mutex_unlock(&ftrace_lock);
6526
6527	if (fail)
6528		return -EINVAL;
6529
6530	return 0;
6531}
6532
6533static ssize_t
6534ftrace_graph_write(struct file *file, const char __user *ubuf,
6535		   size_t cnt, loff_t *ppos)
6536{
6537	ssize_t read, ret = 0;
6538	struct ftrace_graph_data *fgd = file->private_data;
6539	struct trace_parser *parser;
6540
6541	if (!cnt)
6542		return 0;
6543
6544	/* Read mode uses seq functions */
6545	if (file->f_mode & FMODE_READ) {
6546		struct seq_file *m = file->private_data;
6547		fgd = m->private;
6548	}
6549
6550	parser = &fgd->parser;
6551
6552	read = trace_get_user(parser, ubuf, cnt, ppos);
6553
6554	if (read >= 0 && trace_parser_loaded(parser) &&
6555	    !trace_parser_cont(parser)) {
6556
6557		ret = ftrace_graph_set_hash(fgd->new_hash,
6558					    parser->buffer);
6559		trace_parser_clear(parser);
6560	}
6561
6562	if (!ret)
6563		ret = read;
6564
6565	return ret;
6566}
6567
6568static const struct file_operations ftrace_graph_fops = {
6569	.open		= ftrace_graph_open,
6570	.read		= seq_read,
6571	.write		= ftrace_graph_write,
6572	.llseek		= tracing_lseek,
6573	.release	= ftrace_graph_release,
6574};
6575
6576static const struct file_operations ftrace_graph_notrace_fops = {
6577	.open		= ftrace_graph_notrace_open,
6578	.read		= seq_read,
6579	.write		= ftrace_graph_write,
6580	.llseek		= tracing_lseek,
6581	.release	= ftrace_graph_release,
6582};
6583#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6584
6585void ftrace_create_filter_files(struct ftrace_ops *ops,
6586				struct dentry *parent)
6587{
6588
6589	trace_create_file("set_ftrace_filter", TRACE_MODE_WRITE, parent,
6590			  ops, &ftrace_filter_fops);
6591
6592	trace_create_file("set_ftrace_notrace", TRACE_MODE_WRITE, parent,
6593			  ops, &ftrace_notrace_fops);
6594}
6595
6596/*
6597 * The name "destroy_filter_files" is really a misnomer. Although
6598 * in the future, it may actually delete the files, but this is
6599 * really intended to make sure the ops passed in are disabled
6600 * and that when this function returns, the caller is free to
6601 * free the ops.
6602 *
6603 * The "destroy" name is only to match the "create" name that this
6604 * should be paired with.
6605 */
6606void ftrace_destroy_filter_files(struct ftrace_ops *ops)
6607{
6608	mutex_lock(&ftrace_lock);
6609	if (ops->flags & FTRACE_OPS_FL_ENABLED)
6610		ftrace_shutdown(ops, 0);
6611	ops->flags |= FTRACE_OPS_FL_DELETED;
6612	ftrace_free_filter(ops);
6613	mutex_unlock(&ftrace_lock);
6614}
6615
6616static __init int ftrace_init_dyn_tracefs(struct dentry *d_tracer)
6617{
6618
6619	trace_create_file("available_filter_functions", TRACE_MODE_READ,
6620			d_tracer, NULL, &ftrace_avail_fops);
6621
6622	trace_create_file("enabled_functions", TRACE_MODE_READ,
6623			d_tracer, NULL, &ftrace_enabled_fops);
6624
6625	ftrace_create_filter_files(&global_ops, d_tracer);
6626
6627#ifdef CONFIG_FUNCTION_GRAPH_TRACER
6628	trace_create_file("set_graph_function", TRACE_MODE_WRITE, d_tracer,
6629				    NULL,
6630				    &ftrace_graph_fops);
6631	trace_create_file("set_graph_notrace", TRACE_MODE_WRITE, d_tracer,
6632				    NULL,
6633				    &ftrace_graph_notrace_fops);
6634#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
6635
6636	return 0;
6637}
6638
6639static int ftrace_cmp_ips(const void *a, const void *b)
6640{
6641	const unsigned long *ipa = a;
6642	const unsigned long *ipb = b;
6643
6644	if (*ipa > *ipb)
6645		return 1;
6646	if (*ipa < *ipb)
6647		return -1;
6648	return 0;
6649}
6650
6651#ifdef CONFIG_FTRACE_SORT_STARTUP_TEST
6652static void test_is_sorted(unsigned long *start, unsigned long count)
6653{
6654	int i;
6655
6656	for (i = 1; i < count; i++) {
6657		if (WARN(start[i - 1] > start[i],
6658			 "[%d] %pS at %lx is not sorted with %pS at %lx\n", i,
6659			 (void *)start[i - 1], start[i - 1],
6660			 (void *)start[i], start[i]))
6661			break;
6662	}
6663	if (i == count)
6664		pr_info("ftrace section at %px sorted properly\n", start);
6665}
6666#else
6667static void test_is_sorted(unsigned long *start, unsigned long count)
6668{
6669}
6670#endif
6671
6672static int ftrace_process_locs(struct module *mod,
6673			       unsigned long *start,
6674			       unsigned long *end)
6675{
6676	struct ftrace_page *start_pg;
6677	struct ftrace_page *pg;
6678	struct dyn_ftrace *rec;
6679	unsigned long count;
6680	unsigned long *p;
6681	unsigned long addr;
6682	unsigned long flags = 0; /* Shut up gcc */
6683	int ret = -ENOMEM;
6684
6685	count = end - start;
6686
6687	if (!count)
6688		return 0;
6689
6690	/*
6691	 * Sorting mcount in vmlinux at build time depend on
6692	 * CONFIG_BUILDTIME_MCOUNT_SORT, while mcount loc in
6693	 * modules can not be sorted at build time.
6694	 */
6695	if (!IS_ENABLED(CONFIG_BUILDTIME_MCOUNT_SORT) || mod) {
6696		sort(start, count, sizeof(*start),
6697		     ftrace_cmp_ips, NULL);
6698	} else {
6699		test_is_sorted(start, count);
6700	}
6701
6702	start_pg = ftrace_allocate_pages(count);
6703	if (!start_pg)
6704		return -ENOMEM;
6705
6706	mutex_lock(&ftrace_lock);
6707
6708	/*
6709	 * Core and each module needs their own pages, as
6710	 * modules will free them when they are removed.
6711	 * Force a new page to be allocated for modules.
6712	 */
6713	if (!mod) {
6714		WARN_ON(ftrace_pages || ftrace_pages_start);
6715		/* First initialization */
6716		ftrace_pages = ftrace_pages_start = start_pg;
6717	} else {
6718		if (!ftrace_pages)
6719			goto out;
6720
6721		if (WARN_ON(ftrace_pages->next)) {
6722			/* Hmm, we have free pages? */
6723			while (ftrace_pages->next)
6724				ftrace_pages = ftrace_pages->next;
6725		}
6726
6727		ftrace_pages->next = start_pg;
6728	}
6729
6730	p = start;
6731	pg = start_pg;
6732	while (p < end) {
6733		unsigned long end_offset;
6734		addr = ftrace_call_adjust(*p++);
6735		/*
6736		 * Some architecture linkers will pad between
6737		 * the different mcount_loc sections of different
6738		 * object files to satisfy alignments.
6739		 * Skip any NULL pointers.
6740		 */
6741		if (!addr)
6742			continue;
6743
6744		end_offset = (pg->index+1) * sizeof(pg->records[0]);
6745		if (end_offset > PAGE_SIZE << pg->order) {
6746			/* We should have allocated enough */
6747			if (WARN_ON(!pg->next))
6748				break;
6749			pg = pg->next;
6750		}
6751
6752		rec = &pg->records[pg->index++];
6753		rec->ip = addr;
6754	}
6755
6756	/* We should have used all pages */
6757	WARN_ON(pg->next);
6758
6759	/* Assign the last page to ftrace_pages */
6760	ftrace_pages = pg;
6761
6762	/*
6763	 * We only need to disable interrupts on start up
6764	 * because we are modifying code that an interrupt
6765	 * may execute, and the modification is not atomic.
6766	 * But for modules, nothing runs the code we modify
6767	 * until we are finished with it, and there's no
6768	 * reason to cause large interrupt latencies while we do it.
6769	 */
6770	if (!mod)
6771		local_irq_save(flags);
6772	ftrace_update_code(mod, start_pg);
6773	if (!mod)
6774		local_irq_restore(flags);
6775	ret = 0;
6776 out:
6777	mutex_unlock(&ftrace_lock);
6778
6779	return ret;
6780}
6781
6782struct ftrace_mod_func {
6783	struct list_head	list;
6784	char			*name;
6785	unsigned long		ip;
6786	unsigned int		size;
6787};
6788
6789struct ftrace_mod_map {
6790	struct rcu_head		rcu;
6791	struct list_head	list;
6792	struct module		*mod;
6793	unsigned long		start_addr;
6794	unsigned long		end_addr;
6795	struct list_head	funcs;
6796	unsigned int		num_funcs;
6797};
6798
6799static int ftrace_get_trampoline_kallsym(unsigned int symnum,
6800					 unsigned long *value, char *type,
6801					 char *name, char *module_name,
6802					 int *exported)
6803{
6804	struct ftrace_ops *op;
6805
6806	list_for_each_entry_rcu(op, &ftrace_ops_trampoline_list, list) {
6807		if (!op->trampoline || symnum--)
6808			continue;
6809		*value = op->trampoline;
6810		*type = 't';
6811		strlcpy(name, FTRACE_TRAMPOLINE_SYM, KSYM_NAME_LEN);
6812		strlcpy(module_name, FTRACE_TRAMPOLINE_MOD, MODULE_NAME_LEN);
6813		*exported = 0;
6814		return 0;
6815	}
6816
6817	return -ERANGE;
6818}
6819
6820#if defined(CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS) || defined(CONFIG_MODULES)
6821/*
6822 * Check if the current ops references the given ip.
6823 *
6824 * If the ops traces all functions, then it was already accounted for.
6825 * If the ops does not trace the current record function, skip it.
6826 * If the ops ignores the function via notrace filter, skip it.
6827 */
6828static bool
6829ops_references_ip(struct ftrace_ops *ops, unsigned long ip)
6830{
6831	/* If ops isn't enabled, ignore it */
6832	if (!(ops->flags & FTRACE_OPS_FL_ENABLED))
6833		return false;
6834
6835	/* If ops traces all then it includes this function */
6836	if (ops_traces_mod(ops))
6837		return true;
6838
6839	/* The function must be in the filter */
6840	if (!ftrace_hash_empty(ops->func_hash->filter_hash) &&
6841	    !__ftrace_lookup_ip(ops->func_hash->filter_hash, ip))
6842		return false;
6843
6844	/* If in notrace hash, we ignore it too */
6845	if (ftrace_lookup_ip(ops->func_hash->notrace_hash, ip))
6846		return false;
6847
6848	return true;
6849}
6850#endif
6851
6852#ifdef CONFIG_MODULES
6853
6854#define next_to_ftrace_page(p) container_of(p, struct ftrace_page, next)
6855
6856static LIST_HEAD(ftrace_mod_maps);
6857
6858static int referenced_filters(struct dyn_ftrace *rec)
6859{
6860	struct ftrace_ops *ops;
6861	int cnt = 0;
6862
6863	for (ops = ftrace_ops_list; ops != &ftrace_list_end; ops = ops->next) {
6864		if (ops_references_ip(ops, rec->ip)) {
6865			if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_DIRECT))
6866				continue;
6867			if (WARN_ON_ONCE(ops->flags & FTRACE_OPS_FL_IPMODIFY))
6868				continue;
6869			cnt++;
6870			if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
6871				rec->flags |= FTRACE_FL_REGS;
6872			if (cnt == 1 && ops->trampoline)
6873				rec->flags |= FTRACE_FL_TRAMP;
6874			else
6875				rec->flags &= ~FTRACE_FL_TRAMP;
6876		}
6877	}
6878
6879	return cnt;
6880}
6881
6882static void
6883clear_mod_from_hash(struct ftrace_page *pg, struct ftrace_hash *hash)
6884{
6885	struct ftrace_func_entry *entry;
6886	struct dyn_ftrace *rec;
6887	int i;
6888
6889	if (ftrace_hash_empty(hash))
6890		return;
6891
6892	for (i = 0; i < pg->index; i++) {
6893		rec = &pg->records[i];
6894		entry = __ftrace_lookup_ip(hash, rec->ip);
6895		/*
6896		 * Do not allow this rec to match again.
6897		 * Yeah, it may waste some memory, but will be removed
6898		 * if/when the hash is modified again.
6899		 */
6900		if (entry)
6901			entry->ip = 0;
6902	}
6903}
6904
6905/* Clear any records from hashes */
6906static void clear_mod_from_hashes(struct ftrace_page *pg)
6907{
6908	struct trace_array *tr;
6909
6910	mutex_lock(&trace_types_lock);
6911	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
6912		if (!tr->ops || !tr->ops->func_hash)
6913			continue;
6914		mutex_lock(&tr->ops->func_hash->regex_lock);
6915		clear_mod_from_hash(pg, tr->ops->func_hash->filter_hash);
6916		clear_mod_from_hash(pg, tr->ops->func_hash->notrace_hash);
6917		mutex_unlock(&tr->ops->func_hash->regex_lock);
6918	}
6919	mutex_unlock(&trace_types_lock);
6920}
6921
6922static void ftrace_free_mod_map(struct rcu_head *rcu)
6923{
6924	struct ftrace_mod_map *mod_map = container_of(rcu, struct ftrace_mod_map, rcu);
6925	struct ftrace_mod_func *mod_func;
6926	struct ftrace_mod_func *n;
6927
6928	/* All the contents of mod_map are now not visible to readers */
6929	list_for_each_entry_safe(mod_func, n, &mod_map->funcs, list) {
6930		kfree(mod_func->name);
6931		list_del(&mod_func->list);
6932		kfree(mod_func);
6933	}
6934
6935	kfree(mod_map);
6936}
6937
6938void ftrace_release_mod(struct module *mod)
6939{
6940	struct ftrace_mod_map *mod_map;
6941	struct ftrace_mod_map *n;
6942	struct dyn_ftrace *rec;
6943	struct ftrace_page **last_pg;
6944	struct ftrace_page *tmp_page = NULL;
6945	struct ftrace_page *pg;
 
6946
6947	mutex_lock(&ftrace_lock);
6948
6949	if (ftrace_disabled)
6950		goto out_unlock;
6951
6952	list_for_each_entry_safe(mod_map, n, &ftrace_mod_maps, list) {
6953		if (mod_map->mod == mod) {
6954			list_del_rcu(&mod_map->list);
6955			call_rcu(&mod_map->rcu, ftrace_free_mod_map);
6956			break;
6957		}
6958	}
6959
6960	/*
6961	 * Each module has its own ftrace_pages, remove
6962	 * them from the list.
6963	 */
6964	last_pg = &ftrace_pages_start;
6965	for (pg = ftrace_pages_start; pg; pg = *last_pg) {
6966		rec = &pg->records[0];
6967		if (within_module_core(rec->ip, mod) ||
6968		    within_module_init(rec->ip, mod)) {
6969			/*
6970			 * As core pages are first, the first
6971			 * page should never be a module page.
6972			 */
6973			if (WARN_ON(pg == ftrace_pages_start))
6974				goto out_unlock;
6975
6976			/* Check if we are deleting the last page */
6977			if (pg == ftrace_pages)
6978				ftrace_pages = next_to_ftrace_page(last_pg);
6979
6980			ftrace_update_tot_cnt -= pg->index;
6981			*last_pg = pg->next;
6982
6983			pg->next = tmp_page;
6984			tmp_page = pg;
6985		} else
6986			last_pg = &pg->next;
6987	}
6988 out_unlock:
6989	mutex_unlock(&ftrace_lock);
6990
6991	for (pg = tmp_page; pg; pg = tmp_page) {
6992
6993		/* Needs to be called outside of ftrace_lock */
6994		clear_mod_from_hashes(pg);
6995
6996		if (pg->records) {
6997			free_pages((unsigned long)pg->records, pg->order);
6998			ftrace_number_of_pages -= 1 << pg->order;
6999		}
7000		tmp_page = pg->next;
7001		kfree(pg);
 
7002		ftrace_number_of_groups--;
7003	}
7004}
7005
7006void ftrace_module_enable(struct module *mod)
7007{
7008	struct dyn_ftrace *rec;
7009	struct ftrace_page *pg;
7010
7011	mutex_lock(&ftrace_lock);
7012
7013	if (ftrace_disabled)
7014		goto out_unlock;
7015
7016	/*
7017	 * If the tracing is enabled, go ahead and enable the record.
7018	 *
7019	 * The reason not to enable the record immediately is the
7020	 * inherent check of ftrace_make_nop/ftrace_make_call for
7021	 * correct previous instructions.  Making first the NOP
7022	 * conversion puts the module to the correct state, thus
7023	 * passing the ftrace_make_call check.
7024	 *
7025	 * We also delay this to after the module code already set the
7026	 * text to read-only, as we now need to set it back to read-write
7027	 * so that we can modify the text.
7028	 */
7029	if (ftrace_start_up)
7030		ftrace_arch_code_modify_prepare();
7031
7032	do_for_each_ftrace_rec(pg, rec) {
7033		int cnt;
7034		/*
7035		 * do_for_each_ftrace_rec() is a double loop.
7036		 * module text shares the pg. If a record is
7037		 * not part of this module, then skip this pg,
7038		 * which the "break" will do.
7039		 */
7040		if (!within_module_core(rec->ip, mod) &&
7041		    !within_module_init(rec->ip, mod))
7042			break;
7043
7044		/* Weak functions should still be ignored */
7045		if (!test_for_valid_rec(rec)) {
7046			/* Clear all other flags. Should not be enabled anyway */
7047			rec->flags = FTRACE_FL_DISABLED;
7048			continue;
7049		}
7050
7051		cnt = 0;
7052
7053		/*
7054		 * When adding a module, we need to check if tracers are
7055		 * currently enabled and if they are, and can trace this record,
7056		 * we need to enable the module functions as well as update the
7057		 * reference counts for those function records.
7058		 */
7059		if (ftrace_start_up)
7060			cnt += referenced_filters(rec);
7061
7062		rec->flags &= ~FTRACE_FL_DISABLED;
7063		rec->flags += cnt;
7064
7065		if (ftrace_start_up && cnt) {
7066			int failed = __ftrace_replace_code(rec, 1);
7067			if (failed) {
7068				ftrace_bug(failed, rec);
7069				goto out_loop;
7070			}
7071		}
7072
7073	} while_for_each_ftrace_rec();
7074
7075 out_loop:
7076	if (ftrace_start_up)
7077		ftrace_arch_code_modify_post_process();
7078
7079 out_unlock:
7080	mutex_unlock(&ftrace_lock);
7081
7082	process_cached_mods(mod->name);
7083}
7084
7085void ftrace_module_init(struct module *mod)
7086{
7087	int ret;
7088
7089	if (ftrace_disabled || !mod->num_ftrace_callsites)
7090		return;
7091
7092	ret = ftrace_process_locs(mod, mod->ftrace_callsites,
7093				  mod->ftrace_callsites + mod->num_ftrace_callsites);
7094	if (ret)
7095		pr_warn("ftrace: failed to allocate entries for module '%s' functions\n",
7096			mod->name);
7097}
7098
7099static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7100				struct dyn_ftrace *rec)
7101{
7102	struct ftrace_mod_func *mod_func;
7103	unsigned long symsize;
7104	unsigned long offset;
7105	char str[KSYM_SYMBOL_LEN];
7106	char *modname;
7107	const char *ret;
7108
7109	ret = kallsyms_lookup(rec->ip, &symsize, &offset, &modname, str);
7110	if (!ret)
7111		return;
7112
7113	mod_func = kmalloc(sizeof(*mod_func), GFP_KERNEL);
7114	if (!mod_func)
7115		return;
7116
7117	mod_func->name = kstrdup(str, GFP_KERNEL);
7118	if (!mod_func->name) {
7119		kfree(mod_func);
7120		return;
7121	}
7122
7123	mod_func->ip = rec->ip - offset;
7124	mod_func->size = symsize;
7125
7126	mod_map->num_funcs++;
7127
7128	list_add_rcu(&mod_func->list, &mod_map->funcs);
7129}
7130
7131static struct ftrace_mod_map *
7132allocate_ftrace_mod_map(struct module *mod,
7133			unsigned long start, unsigned long end)
7134{
7135	struct ftrace_mod_map *mod_map;
7136
7137	mod_map = kmalloc(sizeof(*mod_map), GFP_KERNEL);
7138	if (!mod_map)
7139		return NULL;
7140
7141	mod_map->mod = mod;
7142	mod_map->start_addr = start;
7143	mod_map->end_addr = end;
7144	mod_map->num_funcs = 0;
7145
7146	INIT_LIST_HEAD_RCU(&mod_map->funcs);
7147
7148	list_add_rcu(&mod_map->list, &ftrace_mod_maps);
7149
7150	return mod_map;
7151}
7152
7153static const char *
7154ftrace_func_address_lookup(struct ftrace_mod_map *mod_map,
7155			   unsigned long addr, unsigned long *size,
7156			   unsigned long *off, char *sym)
7157{
7158	struct ftrace_mod_func *found_func =  NULL;
7159	struct ftrace_mod_func *mod_func;
7160
7161	list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7162		if (addr >= mod_func->ip &&
7163		    addr < mod_func->ip + mod_func->size) {
7164			found_func = mod_func;
7165			break;
7166		}
7167	}
7168
7169	if (found_func) {
7170		if (size)
7171			*size = found_func->size;
7172		if (off)
7173			*off = addr - found_func->ip;
7174		if (sym)
7175			strlcpy(sym, found_func->name, KSYM_NAME_LEN);
7176
7177		return found_func->name;
7178	}
7179
7180	return NULL;
7181}
7182
7183const char *
7184ftrace_mod_address_lookup(unsigned long addr, unsigned long *size,
7185		   unsigned long *off, char **modname, char *sym)
7186{
7187	struct ftrace_mod_map *mod_map;
7188	const char *ret = NULL;
7189
7190	/* mod_map is freed via call_rcu() */
7191	preempt_disable();
7192	list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7193		ret = ftrace_func_address_lookup(mod_map, addr, size, off, sym);
7194		if (ret) {
7195			if (modname)
7196				*modname = mod_map->mod->name;
7197			break;
7198		}
7199	}
7200	preempt_enable();
7201
7202	return ret;
7203}
7204
7205int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7206			   char *type, char *name,
7207			   char *module_name, int *exported)
7208{
7209	struct ftrace_mod_map *mod_map;
7210	struct ftrace_mod_func *mod_func;
7211	int ret;
7212
7213	preempt_disable();
7214	list_for_each_entry_rcu(mod_map, &ftrace_mod_maps, list) {
7215
7216		if (symnum >= mod_map->num_funcs) {
7217			symnum -= mod_map->num_funcs;
7218			continue;
7219		}
7220
7221		list_for_each_entry_rcu(mod_func, &mod_map->funcs, list) {
7222			if (symnum > 1) {
7223				symnum--;
7224				continue;
7225			}
7226
7227			*value = mod_func->ip;
7228			*type = 'T';
7229			strlcpy(name, mod_func->name, KSYM_NAME_LEN);
7230			strlcpy(module_name, mod_map->mod->name, MODULE_NAME_LEN);
7231			*exported = 1;
7232			preempt_enable();
7233			return 0;
7234		}
7235		WARN_ON(1);
7236		break;
7237	}
7238	ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7239					    module_name, exported);
7240	preempt_enable();
7241	return ret;
7242}
7243
7244#else
7245static void save_ftrace_mod_rec(struct ftrace_mod_map *mod_map,
7246				struct dyn_ftrace *rec) { }
7247static inline struct ftrace_mod_map *
7248allocate_ftrace_mod_map(struct module *mod,
7249			unsigned long start, unsigned long end)
7250{
7251	return NULL;
7252}
7253int ftrace_mod_get_kallsym(unsigned int symnum, unsigned long *value,
7254			   char *type, char *name, char *module_name,
7255			   int *exported)
7256{
7257	int ret;
7258
7259	preempt_disable();
7260	ret = ftrace_get_trampoline_kallsym(symnum, value, type, name,
7261					    module_name, exported);
7262	preempt_enable();
7263	return ret;
7264}
7265#endif /* CONFIG_MODULES */
7266
7267struct ftrace_init_func {
7268	struct list_head list;
7269	unsigned long ip;
7270};
7271
7272/* Clear any init ips from hashes */
7273static void
7274clear_func_from_hash(struct ftrace_init_func *func, struct ftrace_hash *hash)
7275{
7276	struct ftrace_func_entry *entry;
7277
7278	entry = ftrace_lookup_ip(hash, func->ip);
7279	/*
7280	 * Do not allow this rec to match again.
7281	 * Yeah, it may waste some memory, but will be removed
7282	 * if/when the hash is modified again.
7283	 */
7284	if (entry)
7285		entry->ip = 0;
7286}
7287
7288static void
7289clear_func_from_hashes(struct ftrace_init_func *func)
7290{
7291	struct trace_array *tr;
7292
7293	mutex_lock(&trace_types_lock);
7294	list_for_each_entry(tr, &ftrace_trace_arrays, list) {
7295		if (!tr->ops || !tr->ops->func_hash)
7296			continue;
7297		mutex_lock(&tr->ops->func_hash->regex_lock);
7298		clear_func_from_hash(func, tr->ops->func_hash->filter_hash);
7299		clear_func_from_hash(func, tr->ops->func_hash->notrace_hash);
7300		mutex_unlock(&tr->ops->func_hash->regex_lock);
7301	}
7302	mutex_unlock(&trace_types_lock);
7303}
7304
7305static void add_to_clear_hash_list(struct list_head *clear_list,
7306				   struct dyn_ftrace *rec)
7307{
7308	struct ftrace_init_func *func;
7309
7310	func = kmalloc(sizeof(*func), GFP_KERNEL);
7311	if (!func) {
7312		MEM_FAIL(1, "alloc failure, ftrace filter could be stale\n");
7313		return;
7314	}
7315
7316	func->ip = rec->ip;
7317	list_add(&func->list, clear_list);
7318}
7319
7320void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
7321{
7322	unsigned long start = (unsigned long)(start_ptr);
7323	unsigned long end = (unsigned long)(end_ptr);
7324	struct ftrace_page **last_pg = &ftrace_pages_start;
7325	struct ftrace_page *pg;
7326	struct dyn_ftrace *rec;
7327	struct dyn_ftrace key;
7328	struct ftrace_mod_map *mod_map = NULL;
7329	struct ftrace_init_func *func, *func_next;
7330	struct list_head clear_hash;
 
7331
7332	INIT_LIST_HEAD(&clear_hash);
7333
7334	key.ip = start;
7335	key.flags = end;	/* overload flags, as it is unsigned long */
7336
7337	mutex_lock(&ftrace_lock);
7338
7339	/*
7340	 * If we are freeing module init memory, then check if
7341	 * any tracer is active. If so, we need to save a mapping of
7342	 * the module functions being freed with the address.
7343	 */
7344	if (mod && ftrace_ops_list != &ftrace_list_end)
7345		mod_map = allocate_ftrace_mod_map(mod, start, end);
7346
7347	for (pg = ftrace_pages_start; pg; last_pg = &pg->next, pg = *last_pg) {
7348		if (end < pg->records[0].ip ||
7349		    start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
7350			continue;
7351 again:
7352		rec = bsearch(&key, pg->records, pg->index,
7353			      sizeof(struct dyn_ftrace),
7354			      ftrace_cmp_recs);
7355		if (!rec)
7356			continue;
7357
7358		/* rec will be cleared from hashes after ftrace_lock unlock */
7359		add_to_clear_hash_list(&clear_hash, rec);
7360
7361		if (mod_map)
7362			save_ftrace_mod_rec(mod_map, rec);
7363
7364		pg->index--;
7365		ftrace_update_tot_cnt--;
7366		if (!pg->index) {
7367			*last_pg = pg->next;
7368			if (pg->records) {
7369				free_pages((unsigned long)pg->records, pg->order);
7370				ftrace_number_of_pages -= 1 << pg->order;
7371			}
7372			ftrace_number_of_groups--;
7373			kfree(pg);
7374			pg = container_of(last_pg, struct ftrace_page, next);
7375			if (!(*last_pg))
7376				ftrace_pages = pg;
7377			continue;
7378		}
7379		memmove(rec, rec + 1,
7380			(pg->index - (rec - pg->records)) * sizeof(*rec));
7381		/* More than one function may be in this block */
7382		goto again;
7383	}
7384	mutex_unlock(&ftrace_lock);
7385
7386	list_for_each_entry_safe(func, func_next, &clear_hash, list) {
7387		clear_func_from_hashes(func);
7388		kfree(func);
7389	}
7390}
7391
7392void __init ftrace_free_init_mem(void)
7393{
7394	void *start = (void *)(&__init_begin);
7395	void *end = (void *)(&__init_end);
7396
7397	ftrace_boot_snapshot();
7398
7399	ftrace_free_mem(NULL, start, end);
7400}
7401
7402int __init __weak ftrace_dyn_arch_init(void)
7403{
7404	return 0;
7405}
7406
7407void __init ftrace_init(void)
7408{
7409	extern unsigned long __start_mcount_loc[];
7410	extern unsigned long __stop_mcount_loc[];
7411	unsigned long count, flags;
7412	int ret;
7413
7414	local_irq_save(flags);
7415	ret = ftrace_dyn_arch_init();
7416	local_irq_restore(flags);
7417	if (ret)
7418		goto failed;
7419
7420	count = __stop_mcount_loc - __start_mcount_loc;
7421	if (!count) {
7422		pr_info("ftrace: No functions to be traced?\n");
7423		goto failed;
7424	}
7425
7426	pr_info("ftrace: allocating %ld entries in %ld pages\n",
7427		count, DIV_ROUND_UP(count, ENTRIES_PER_PAGE));
 
 
7428
7429	ret = ftrace_process_locs(NULL,
7430				  __start_mcount_loc,
7431				  __stop_mcount_loc);
7432	if (ret) {
7433		pr_warn("ftrace: failed to allocate entries for functions\n");
7434		goto failed;
7435	}
7436
7437	pr_info("ftrace: allocated %ld pages with %ld groups\n",
7438		ftrace_number_of_pages, ftrace_number_of_groups);
7439
7440	last_ftrace_enabled = ftrace_enabled = 1;
7441
7442	set_ftrace_early_filters();
7443
7444	return;
7445 failed:
7446	ftrace_disabled = 1;
7447}
7448
7449/* Do nothing if arch does not support this */
7450void __weak arch_ftrace_update_trampoline(struct ftrace_ops *ops)
7451{
7452}
7453
7454static void ftrace_update_trampoline(struct ftrace_ops *ops)
7455{
7456	unsigned long trampoline = ops->trampoline;
7457
7458	arch_ftrace_update_trampoline(ops);
7459	if (ops->trampoline && ops->trampoline != trampoline &&
7460	    (ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP)) {
7461		/* Add to kallsyms before the perf events */
7462		ftrace_add_trampoline_to_kallsyms(ops);
7463		perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
7464				   ops->trampoline, ops->trampoline_size, false,
7465				   FTRACE_TRAMPOLINE_SYM);
7466		/*
7467		 * Record the perf text poke event after the ksymbol register
7468		 * event.
7469		 */
7470		perf_event_text_poke((void *)ops->trampoline, NULL, 0,
7471				     (void *)ops->trampoline,
7472				     ops->trampoline_size);
7473	}
7474}
7475
7476void ftrace_init_trace_array(struct trace_array *tr)
7477{
7478	INIT_LIST_HEAD(&tr->func_probes);
7479	INIT_LIST_HEAD(&tr->mod_trace);
7480	INIT_LIST_HEAD(&tr->mod_notrace);
7481}
7482#else
7483
7484struct ftrace_ops global_ops = {
7485	.func			= ftrace_stub,
7486	.flags			= FTRACE_OPS_FL_INITIALIZED |
 
7487				  FTRACE_OPS_FL_PID,
7488};
7489
7490static int __init ftrace_nodyn_init(void)
7491{
7492	ftrace_enabled = 1;
7493	return 0;
7494}
7495core_initcall(ftrace_nodyn_init);
7496
7497static inline int ftrace_init_dyn_tracefs(struct dentry *d_tracer) { return 0; }
 
7498static inline void ftrace_startup_all(int command) { }
7499
 
 
 
7500static void ftrace_update_trampoline(struct ftrace_ops *ops)
7501{
7502}
7503
7504#endif /* CONFIG_DYNAMIC_FTRACE */
7505
7506__init void ftrace_init_global_array_ops(struct trace_array *tr)
7507{
7508	tr->ops = &global_ops;
7509	tr->ops->private = tr;
7510	ftrace_init_trace_array(tr);
7511}
7512
7513void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func)
7514{
7515	/* If we filter on pids, update to use the pid function */
7516	if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
7517		if (WARN_ON(tr->ops->func != ftrace_stub))
7518			printk("ftrace ops had %pS for function\n",
7519			       tr->ops->func);
7520	}
7521	tr->ops->func = func;
7522	tr->ops->private = tr;
7523}
7524
7525void ftrace_reset_array_ops(struct trace_array *tr)
7526{
7527	tr->ops->func = ftrace_stub;
7528}
7529
7530static nokprobe_inline void
7531__ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7532		       struct ftrace_ops *ignored, struct ftrace_regs *fregs)
7533{
7534	struct pt_regs *regs = ftrace_get_regs(fregs);
7535	struct ftrace_ops *op;
7536	int bit;
7537
7538	/*
7539	 * The ftrace_test_and_set_recursion() will disable preemption,
7540	 * which is required since some of the ops may be dynamically
7541	 * allocated, they must be freed after a synchronize_rcu().
7542	 */
7543	bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7544	if (bit < 0)
7545		return;
7546
 
 
 
 
 
 
7547	do_for_each_ftrace_op(op, ftrace_ops_list) {
7548		/* Stub functions don't need to be called nor tested */
7549		if (op->flags & FTRACE_OPS_FL_STUB)
7550			continue;
7551		/*
7552		 * Check the following for each ops before calling their func:
7553		 *  if RCU flag is set, then rcu_is_watching() must be true
 
 
7554		 *  Otherwise test if the ip matches the ops filter
7555		 *
7556		 * If any of the above fails then the op->func() is not executed.
7557		 */
7558		if ((!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching()) &&
7559		    ftrace_ops_test(op, ip, regs)) {
7560			if (FTRACE_WARN_ON(!op->func)) {
7561				pr_warn("op=%p %pS\n", op, op);
7562				goto out;
7563			}
7564			op->func(ip, parent_ip, op, fregs);
7565		}
7566	} while_for_each_ftrace_op(op);
7567out:
 
7568	trace_clear_recursion(bit);
7569}
7570
7571/*
7572 * Some archs only support passing ip and parent_ip. Even though
7573 * the list function ignores the op parameter, we do not want any
7574 * C side effects, where a function is called without the caller
7575 * sending a third parameter.
7576 * Archs are to support both the regs and ftrace_ops at the same time.
7577 * If they support ftrace_ops, it is assumed they support regs.
7578 * If call backs want to use regs, they must either check for regs
7579 * being NULL, or CONFIG_DYNAMIC_FTRACE_WITH_REGS.
7580 * Note, CONFIG_DYNAMIC_FTRACE_WITH_REGS expects a full regs to be saved.
7581 * An architecture can pass partial regs with ftrace_ops and still
7582 * set the ARCH_SUPPORTS_FTRACE_OPS.
7583 *
7584 * In vmlinux.lds.h, ftrace_ops_list_func() is defined to be
7585 * arch_ftrace_ops_list_func.
7586 */
7587#if ARCH_SUPPORTS_FTRACE_OPS
7588void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
7589			       struct ftrace_ops *op, struct ftrace_regs *fregs)
7590{
7591	__ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
7592}
 
7593#else
7594void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip)
7595{
7596	__ftrace_ops_list_func(ip, parent_ip, NULL, NULL);
7597}
 
7598#endif
7599NOKPROBE_SYMBOL(arch_ftrace_ops_list_func);
7600
7601/*
7602 * If there's only one function registered but it does not support
7603 * recursion, needs RCU protection, then this function will be called
7604 * by the mcount trampoline.
7605 */
7606static void ftrace_ops_assist_func(unsigned long ip, unsigned long parent_ip,
7607				   struct ftrace_ops *op, struct ftrace_regs *fregs)
7608{
7609	int bit;
7610
7611	bit = trace_test_and_set_recursion(ip, parent_ip, TRACE_LIST_START);
7612	if (bit < 0)
7613		return;
7614
 
 
7615	if (!(op->flags & FTRACE_OPS_FL_RCU) || rcu_is_watching())
7616		op->func(ip, parent_ip, op, fregs);
7617
 
7618	trace_clear_recursion(bit);
7619}
7620NOKPROBE_SYMBOL(ftrace_ops_assist_func);
7621
7622/**
7623 * ftrace_ops_get_func - get the function a trampoline should call
7624 * @ops: the ops to get the function for
7625 *
7626 * Normally the mcount trampoline will call the ops->func, but there
7627 * are times that it should not. For example, if the ops does not
7628 * have its own recursion protection, then it should call the
7629 * ftrace_ops_assist_func() instead.
7630 *
7631 * Returns the function that the trampoline should call for @ops.
7632 */
7633ftrace_func_t ftrace_ops_get_func(struct ftrace_ops *ops)
7634{
7635	/*
7636	 * If the function does not handle recursion or needs to be RCU safe,
7637	 * then we need to call the assist handler.
7638	 */
7639	if (ops->flags & (FTRACE_OPS_FL_RECURSION |
7640			  FTRACE_OPS_FL_RCU))
7641		return ftrace_ops_assist_func;
7642
7643	return ops->func;
7644}
7645
7646static void
7647ftrace_filter_pid_sched_switch_probe(void *data, bool preempt,
7648				     struct task_struct *prev,
7649				     struct task_struct *next,
7650				     unsigned int prev_state)
7651{
7652	struct trace_array *tr = data;
7653	struct trace_pid_list *pid_list;
7654	struct trace_pid_list *no_pid_list;
7655
7656	pid_list = rcu_dereference_sched(tr->function_pids);
7657	no_pid_list = rcu_dereference_sched(tr->function_no_pids);
7658
7659	if (trace_ignore_this_task(pid_list, no_pid_list, next))
7660		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7661			       FTRACE_PID_IGNORE);
7662	else
7663		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7664			       next->pid);
7665}
7666
7667static void
7668ftrace_pid_follow_sched_process_fork(void *data,
7669				     struct task_struct *self,
7670				     struct task_struct *task)
7671{
7672	struct trace_pid_list *pid_list;
7673	struct trace_array *tr = data;
7674
7675	pid_list = rcu_dereference_sched(tr->function_pids);
7676	trace_filter_add_remove_task(pid_list, self, task);
7677
7678	pid_list = rcu_dereference_sched(tr->function_no_pids);
7679	trace_filter_add_remove_task(pid_list, self, task);
7680}
7681
7682static void
7683ftrace_pid_follow_sched_process_exit(void *data, struct task_struct *task)
7684{
7685	struct trace_pid_list *pid_list;
7686	struct trace_array *tr = data;
7687
7688	pid_list = rcu_dereference_sched(tr->function_pids);
7689	trace_filter_add_remove_task(pid_list, NULL, task);
7690
7691	pid_list = rcu_dereference_sched(tr->function_no_pids);
7692	trace_filter_add_remove_task(pid_list, NULL, task);
7693}
7694
7695void ftrace_pid_follow_fork(struct trace_array *tr, bool enable)
7696{
7697	if (enable) {
7698		register_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7699						  tr);
7700		register_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7701						  tr);
7702	} else {
7703		unregister_trace_sched_process_fork(ftrace_pid_follow_sched_process_fork,
7704						    tr);
7705		unregister_trace_sched_process_free(ftrace_pid_follow_sched_process_exit,
7706						    tr);
7707	}
7708}
7709
7710static void clear_ftrace_pids(struct trace_array *tr, int type)
7711{
7712	struct trace_pid_list *pid_list;
7713	struct trace_pid_list *no_pid_list;
7714	int cpu;
7715
7716	pid_list = rcu_dereference_protected(tr->function_pids,
7717					     lockdep_is_held(&ftrace_lock));
7718	no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7719						lockdep_is_held(&ftrace_lock));
7720
7721	/* Make sure there's something to do */
7722	if (!pid_type_enabled(type, pid_list, no_pid_list))
7723		return;
7724
7725	/* See if the pids still need to be checked after this */
7726	if (!still_need_pid_events(type, pid_list, no_pid_list)) {
7727		unregister_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7728		for_each_possible_cpu(cpu)
7729			per_cpu_ptr(tr->array_buffer.data, cpu)->ftrace_ignore_pid = FTRACE_PID_TRACE;
7730	}
7731
7732	if (type & TRACE_PIDS)
7733		rcu_assign_pointer(tr->function_pids, NULL);
7734
7735	if (type & TRACE_NO_PIDS)
7736		rcu_assign_pointer(tr->function_no_pids, NULL);
7737
7738	/* Wait till all users are no longer using pid filtering */
7739	synchronize_rcu();
7740
7741	if ((type & TRACE_PIDS) && pid_list)
7742		trace_pid_list_free(pid_list);
7743
7744	if ((type & TRACE_NO_PIDS) && no_pid_list)
7745		trace_pid_list_free(no_pid_list);
7746}
7747
7748void ftrace_clear_pids(struct trace_array *tr)
7749{
7750	mutex_lock(&ftrace_lock);
7751
7752	clear_ftrace_pids(tr, TRACE_PIDS | TRACE_NO_PIDS);
7753
7754	mutex_unlock(&ftrace_lock);
7755}
7756
7757static void ftrace_pid_reset(struct trace_array *tr, int type)
7758{
7759	mutex_lock(&ftrace_lock);
7760	clear_ftrace_pids(tr, type);
7761
7762	ftrace_update_pid_func();
7763	ftrace_startup_all(0);
7764
7765	mutex_unlock(&ftrace_lock);
7766}
7767
7768/* Greater than any max PID */
7769#define FTRACE_NO_PIDS		(void *)(PID_MAX_LIMIT + 1)
7770
7771static void *fpid_start(struct seq_file *m, loff_t *pos)
7772	__acquires(RCU)
7773{
7774	struct trace_pid_list *pid_list;
7775	struct trace_array *tr = m->private;
7776
7777	mutex_lock(&ftrace_lock);
7778	rcu_read_lock_sched();
7779
7780	pid_list = rcu_dereference_sched(tr->function_pids);
7781
7782	if (!pid_list)
7783		return !(*pos) ? FTRACE_NO_PIDS : NULL;
7784
7785	return trace_pid_start(pid_list, pos);
7786}
7787
7788static void *fpid_next(struct seq_file *m, void *v, loff_t *pos)
7789{
7790	struct trace_array *tr = m->private;
7791	struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_pids);
7792
7793	if (v == FTRACE_NO_PIDS) {
7794		(*pos)++;
7795		return NULL;
7796	}
7797	return trace_pid_next(pid_list, v, pos);
7798}
7799
7800static void fpid_stop(struct seq_file *m, void *p)
7801	__releases(RCU)
7802{
7803	rcu_read_unlock_sched();
7804	mutex_unlock(&ftrace_lock);
7805}
7806
7807static int fpid_show(struct seq_file *m, void *v)
7808{
7809	if (v == FTRACE_NO_PIDS) {
7810		seq_puts(m, "no pid\n");
7811		return 0;
7812	}
7813
7814	return trace_pid_show(m, v);
7815}
7816
7817static const struct seq_operations ftrace_pid_sops = {
7818	.start = fpid_start,
7819	.next = fpid_next,
7820	.stop = fpid_stop,
7821	.show = fpid_show,
7822};
7823
7824static void *fnpid_start(struct seq_file *m, loff_t *pos)
7825	__acquires(RCU)
7826{
7827	struct trace_pid_list *pid_list;
7828	struct trace_array *tr = m->private;
7829
7830	mutex_lock(&ftrace_lock);
7831	rcu_read_lock_sched();
7832
7833	pid_list = rcu_dereference_sched(tr->function_no_pids);
7834
7835	if (!pid_list)
7836		return !(*pos) ? FTRACE_NO_PIDS : NULL;
7837
7838	return trace_pid_start(pid_list, pos);
7839}
7840
7841static void *fnpid_next(struct seq_file *m, void *v, loff_t *pos)
7842{
7843	struct trace_array *tr = m->private;
7844	struct trace_pid_list *pid_list = rcu_dereference_sched(tr->function_no_pids);
7845
7846	if (v == FTRACE_NO_PIDS) {
7847		(*pos)++;
7848		return NULL;
7849	}
7850	return trace_pid_next(pid_list, v, pos);
7851}
7852
7853static const struct seq_operations ftrace_no_pid_sops = {
7854	.start = fnpid_start,
7855	.next = fnpid_next,
7856	.stop = fpid_stop,
7857	.show = fpid_show,
7858};
7859
7860static int pid_open(struct inode *inode, struct file *file, int type)
7861{
7862	const struct seq_operations *seq_ops;
7863	struct trace_array *tr = inode->i_private;
7864	struct seq_file *m;
7865	int ret = 0;
7866
7867	ret = tracing_check_open_get_tr(tr);
7868	if (ret)
7869		return ret;
7870
7871	if ((file->f_mode & FMODE_WRITE) &&
7872	    (file->f_flags & O_TRUNC))
7873		ftrace_pid_reset(tr, type);
7874
7875	switch (type) {
7876	case TRACE_PIDS:
7877		seq_ops = &ftrace_pid_sops;
7878		break;
7879	case TRACE_NO_PIDS:
7880		seq_ops = &ftrace_no_pid_sops;
7881		break;
7882	default:
7883		trace_array_put(tr);
7884		WARN_ON_ONCE(1);
7885		return -EINVAL;
7886	}
7887
7888	ret = seq_open(file, seq_ops);
7889	if (ret < 0) {
7890		trace_array_put(tr);
7891	} else {
7892		m = file->private_data;
7893		/* copy tr over to seq ops */
7894		m->private = tr;
7895	}
7896
7897	return ret;
7898}
7899
7900static int
7901ftrace_pid_open(struct inode *inode, struct file *file)
7902{
7903	return pid_open(inode, file, TRACE_PIDS);
7904}
7905
7906static int
7907ftrace_no_pid_open(struct inode *inode, struct file *file)
7908{
7909	return pid_open(inode, file, TRACE_NO_PIDS);
7910}
7911
7912static void ignore_task_cpu(void *data)
7913{
7914	struct trace_array *tr = data;
7915	struct trace_pid_list *pid_list;
7916	struct trace_pid_list *no_pid_list;
7917
7918	/*
7919	 * This function is called by on_each_cpu() while the
7920	 * event_mutex is held.
7921	 */
7922	pid_list = rcu_dereference_protected(tr->function_pids,
7923					     mutex_is_locked(&ftrace_lock));
7924	no_pid_list = rcu_dereference_protected(tr->function_no_pids,
7925						mutex_is_locked(&ftrace_lock));
7926
7927	if (trace_ignore_this_task(pid_list, no_pid_list, current))
7928		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7929			       FTRACE_PID_IGNORE);
7930	else
7931		this_cpu_write(tr->array_buffer.data->ftrace_ignore_pid,
7932			       current->pid);
7933}
7934
7935static ssize_t
7936pid_write(struct file *filp, const char __user *ubuf,
7937	  size_t cnt, loff_t *ppos, int type)
7938{
7939	struct seq_file *m = filp->private_data;
7940	struct trace_array *tr = m->private;
7941	struct trace_pid_list *filtered_pids;
7942	struct trace_pid_list *other_pids;
7943	struct trace_pid_list *pid_list;
7944	ssize_t ret;
7945
7946	if (!cnt)
7947		return 0;
7948
7949	mutex_lock(&ftrace_lock);
7950
7951	switch (type) {
7952	case TRACE_PIDS:
7953		filtered_pids = rcu_dereference_protected(tr->function_pids,
7954					     lockdep_is_held(&ftrace_lock));
7955		other_pids = rcu_dereference_protected(tr->function_no_pids,
7956					     lockdep_is_held(&ftrace_lock));
7957		break;
7958	case TRACE_NO_PIDS:
7959		filtered_pids = rcu_dereference_protected(tr->function_no_pids,
7960					     lockdep_is_held(&ftrace_lock));
7961		other_pids = rcu_dereference_protected(tr->function_pids,
7962					     lockdep_is_held(&ftrace_lock));
7963		break;
7964	default:
7965		ret = -EINVAL;
7966		WARN_ON_ONCE(1);
7967		goto out;
7968	}
7969
7970	ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt);
7971	if (ret < 0)
7972		goto out;
7973
7974	switch (type) {
7975	case TRACE_PIDS:
7976		rcu_assign_pointer(tr->function_pids, pid_list);
7977		break;
7978	case TRACE_NO_PIDS:
7979		rcu_assign_pointer(tr->function_no_pids, pid_list);
7980		break;
7981	}
7982
7983
7984	if (filtered_pids) {
7985		synchronize_rcu();
7986		trace_pid_list_free(filtered_pids);
7987	} else if (pid_list && !other_pids) {
7988		/* Register a probe to set whether to ignore the tracing of a task */
7989		register_trace_sched_switch(ftrace_filter_pid_sched_switch_probe, tr);
7990	}
7991
7992	/*
7993	 * Ignoring of pids is done at task switch. But we have to
7994	 * check for those tasks that are currently running.
7995	 * Always do this in case a pid was appended or removed.
7996	 */
7997	on_each_cpu(ignore_task_cpu, tr, 1);
7998
7999	ftrace_update_pid_func();
8000	ftrace_startup_all(0);
8001 out:
8002	mutex_unlock(&ftrace_lock);
8003
8004	if (ret > 0)
8005		*ppos += ret;
8006
8007	return ret;
8008}
8009
8010static ssize_t
8011ftrace_pid_write(struct file *filp, const char __user *ubuf,
8012		 size_t cnt, loff_t *ppos)
8013{
8014	return pid_write(filp, ubuf, cnt, ppos, TRACE_PIDS);
8015}
8016
8017static ssize_t
8018ftrace_no_pid_write(struct file *filp, const char __user *ubuf,
8019		    size_t cnt, loff_t *ppos)
8020{
8021	return pid_write(filp, ubuf, cnt, ppos, TRACE_NO_PIDS);
8022}
8023
8024static int
8025ftrace_pid_release(struct inode *inode, struct file *file)
8026{
8027	struct trace_array *tr = inode->i_private;
8028
8029	trace_array_put(tr);
8030
8031	return seq_release(inode, file);
8032}
8033
8034static const struct file_operations ftrace_pid_fops = {
8035	.open		= ftrace_pid_open,
8036	.write		= ftrace_pid_write,
8037	.read		= seq_read,
8038	.llseek		= tracing_lseek,
8039	.release	= ftrace_pid_release,
8040};
8041
8042static const struct file_operations ftrace_no_pid_fops = {
8043	.open		= ftrace_no_pid_open,
8044	.write		= ftrace_no_pid_write,
8045	.read		= seq_read,
8046	.llseek		= tracing_lseek,
8047	.release	= ftrace_pid_release,
8048};
8049
8050void ftrace_init_tracefs(struct trace_array *tr, struct dentry *d_tracer)
8051{
8052	trace_create_file("set_ftrace_pid", TRACE_MODE_WRITE, d_tracer,
8053			    tr, &ftrace_pid_fops);
8054	trace_create_file("set_ftrace_notrace_pid", TRACE_MODE_WRITE,
8055			  d_tracer, tr, &ftrace_no_pid_fops);
8056}
8057
8058void __init ftrace_init_tracefs_toplevel(struct trace_array *tr,
8059					 struct dentry *d_tracer)
8060{
8061	/* Only the top level directory has the dyn_tracefs and profile */
8062	WARN_ON(!(tr->flags & TRACE_ARRAY_FL_GLOBAL));
8063
8064	ftrace_init_dyn_tracefs(d_tracer);
8065	ftrace_profile_tracefs(d_tracer);
8066}
8067
8068/**
8069 * ftrace_kill - kill ftrace
8070 *
8071 * This function should be used by panic code. It stops ftrace
8072 * but in a not so nice way. If you need to simply kill ftrace
8073 * from a non-atomic section, use ftrace_kill.
8074 */
8075void ftrace_kill(void)
8076{
8077	ftrace_disabled = 1;
8078	ftrace_enabled = 0;
8079	ftrace_trace_function = ftrace_stub;
8080}
8081
8082/**
8083 * ftrace_is_dead - Test if ftrace is dead or not.
8084 *
8085 * Returns 1 if ftrace is "dead", zero otherwise.
8086 */
8087int ftrace_is_dead(void)
8088{
8089	return ftrace_disabled;
8090}
8091
8092#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
8093/*
8094 * When registering ftrace_ops with IPMODIFY, it is necessary to make sure
8095 * it doesn't conflict with any direct ftrace_ops. If there is existing
8096 * direct ftrace_ops on a kernel function being patched, call
8097 * FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER on it to enable sharing.
8098 *
8099 * @ops:     ftrace_ops being registered.
8100 *
8101 * Returns:
8102 *         0 on success;
8103 *         Negative on failure.
8104 */
8105static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
8106{
8107	struct ftrace_func_entry *entry;
8108	struct ftrace_hash *hash;
8109	struct ftrace_ops *op;
8110	int size, i, ret;
8111
8112	lockdep_assert_held_once(&direct_mutex);
8113
8114	if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
8115		return 0;
8116
8117	hash = ops->func_hash->filter_hash;
8118	size = 1 << hash->size_bits;
8119	for (i = 0; i < size; i++) {
8120		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
8121			unsigned long ip = entry->ip;
8122			bool found_op = false;
8123
8124			mutex_lock(&ftrace_lock);
8125			do_for_each_ftrace_op(op, ftrace_ops_list) {
8126				if (!(op->flags & FTRACE_OPS_FL_DIRECT))
8127					continue;
8128				if (ops_references_ip(op, ip)) {
8129					found_op = true;
8130					break;
8131				}
8132			} while_for_each_ftrace_op(op);
8133			mutex_unlock(&ftrace_lock);
8134
8135			if (found_op) {
8136				if (!op->ops_func)
8137					return -EBUSY;
8138
8139				ret = op->ops_func(op, FTRACE_OPS_CMD_ENABLE_SHARE_IPMODIFY_PEER);
8140				if (ret)
8141					return ret;
8142			}
8143		}
8144	}
8145
8146	return 0;
8147}
8148
8149/*
8150 * Similar to prepare_direct_functions_for_ipmodify, clean up after ops
8151 * with IPMODIFY is unregistered. The cleanup is optional for most DIRECT
8152 * ops.
8153 */
8154static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
8155{
8156	struct ftrace_func_entry *entry;
8157	struct ftrace_hash *hash;
8158	struct ftrace_ops *op;
8159	int size, i;
8160
8161	if (!(ops->flags & FTRACE_OPS_FL_IPMODIFY))
8162		return;
8163
8164	mutex_lock(&direct_mutex);
8165
8166	hash = ops->func_hash->filter_hash;
8167	size = 1 << hash->size_bits;
8168	for (i = 0; i < size; i++) {
8169		hlist_for_each_entry(entry, &hash->buckets[i], hlist) {
8170			unsigned long ip = entry->ip;
8171			bool found_op = false;
8172
8173			mutex_lock(&ftrace_lock);
8174			do_for_each_ftrace_op(op, ftrace_ops_list) {
8175				if (!(op->flags & FTRACE_OPS_FL_DIRECT))
8176					continue;
8177				if (ops_references_ip(op, ip)) {
8178					found_op = true;
8179					break;
8180				}
8181			} while_for_each_ftrace_op(op);
8182			mutex_unlock(&ftrace_lock);
8183
8184			/* The cleanup is optional, ignore any errors */
8185			if (found_op && op->ops_func)
8186				op->ops_func(op, FTRACE_OPS_CMD_DISABLE_SHARE_IPMODIFY_PEER);
8187		}
8188	}
8189	mutex_unlock(&direct_mutex);
8190}
8191
8192#define lock_direct_mutex()	mutex_lock(&direct_mutex)
8193#define unlock_direct_mutex()	mutex_unlock(&direct_mutex)
8194
8195#else  /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8196
8197static int prepare_direct_functions_for_ipmodify(struct ftrace_ops *ops)
8198{
8199	return 0;
8200}
8201
8202static void cleanup_direct_functions_after_ipmodify(struct ftrace_ops *ops)
8203{
8204}
8205
8206#define lock_direct_mutex()	do { } while (0)
8207#define unlock_direct_mutex()	do { } while (0)
8208
8209#endif  /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */
8210
8211/*
8212 * Similar to register_ftrace_function, except we don't lock direct_mutex.
8213 */
8214static int register_ftrace_function_nolock(struct ftrace_ops *ops)
8215{
8216	int ret;
8217
8218	ftrace_ops_init(ops);
8219
8220	mutex_lock(&ftrace_lock);
8221
8222	ret = ftrace_startup(ops, 0);
8223
8224	mutex_unlock(&ftrace_lock);
8225
8226	return ret;
8227}
8228
8229/**
8230 * register_ftrace_function - register a function for profiling
8231 * @ops:	ops structure that holds the function for profiling.
8232 *
8233 * Register a function to be called by all functions in the
8234 * kernel.
8235 *
8236 * Note: @ops->func and all the functions it calls must be labeled
8237 *       with "notrace", otherwise it will go into a
8238 *       recursive loop.
8239 */
8240int register_ftrace_function(struct ftrace_ops *ops)
8241{
8242	int ret;
8243
8244	lock_direct_mutex();
8245	ret = prepare_direct_functions_for_ipmodify(ops);
8246	if (ret < 0)
8247		goto out_unlock;
8248
8249	ret = register_ftrace_function_nolock(ops);
 
 
 
 
8250
8251out_unlock:
8252	unlock_direct_mutex();
8253	return ret;
8254}
8255EXPORT_SYMBOL_GPL(register_ftrace_function);
8256
8257/**
8258 * unregister_ftrace_function - unregister a function for profiling.
8259 * @ops:	ops structure that holds the function to unregister
8260 *
8261 * Unregister a function that was added to be called by ftrace profiling.
8262 */
8263int unregister_ftrace_function(struct ftrace_ops *ops)
8264{
8265	int ret;
8266
8267	mutex_lock(&ftrace_lock);
8268	ret = ftrace_shutdown(ops, 0);
8269	mutex_unlock(&ftrace_lock);
8270
8271	cleanup_direct_functions_after_ipmodify(ops);
8272	return ret;
8273}
8274EXPORT_SYMBOL_GPL(unregister_ftrace_function);
8275
8276static int symbols_cmp(const void *a, const void *b)
8277{
8278	const char **str_a = (const char **) a;
8279	const char **str_b = (const char **) b;
8280
8281	return strcmp(*str_a, *str_b);
8282}
8283
8284struct kallsyms_data {
8285	unsigned long *addrs;
8286	const char **syms;
8287	size_t cnt;
8288	size_t found;
8289};
8290
8291/* This function gets called for all kernel and module symbols
8292 * and returns 1 in case we resolved all the requested symbols,
8293 * 0 otherwise.
8294 */
8295static int kallsyms_callback(void *data, const char *name,
8296			     struct module *mod, unsigned long addr)
8297{
8298	struct kallsyms_data *args = data;
8299	const char **sym;
8300	int idx;
8301
8302	sym = bsearch(&name, args->syms, args->cnt, sizeof(*args->syms), symbols_cmp);
8303	if (!sym)
8304		return 0;
8305
8306	idx = sym - args->syms;
8307	if (args->addrs[idx])
8308		return 0;
8309
8310	if (!ftrace_location(addr))
8311		return 0;
8312
8313	args->addrs[idx] = addr;
8314	args->found++;
8315	return args->found == args->cnt ? 1 : 0;
8316}
8317
8318/**
8319 * ftrace_lookup_symbols - Lookup addresses for array of symbols
8320 *
8321 * @sorted_syms: array of symbols pointers symbols to resolve,
8322 * must be alphabetically sorted
8323 * @cnt: number of symbols/addresses in @syms/@addrs arrays
8324 * @addrs: array for storing resulting addresses
8325 *
8326 * This function looks up addresses for array of symbols provided in
8327 * @syms array (must be alphabetically sorted) and stores them in
8328 * @addrs array, which needs to be big enough to store at least @cnt
8329 * addresses.
8330 *
8331 * This function returns 0 if all provided symbols are found,
8332 * -ESRCH otherwise.
8333 */
8334int ftrace_lookup_symbols(const char **sorted_syms, size_t cnt, unsigned long *addrs)
8335{
8336	struct kallsyms_data args;
8337	int found_all;
8338
8339	memset(addrs, 0, sizeof(*addrs) * cnt);
8340	args.addrs = addrs;
8341	args.syms = sorted_syms;
8342	args.cnt = cnt;
8343	args.found = 0;
8344
8345	found_all = kallsyms_on_each_symbol(kallsyms_callback, &args);
8346	if (found_all)
8347		return 0;
8348	found_all = module_kallsyms_on_each_symbol(kallsyms_callback, &args);
8349	return found_all ? 0 : -ESRCH;
8350}
8351
8352#ifdef CONFIG_SYSCTL
8353
8354#ifdef CONFIG_DYNAMIC_FTRACE
8355static void ftrace_startup_sysctl(void)
8356{
8357	int command;
8358
8359	if (unlikely(ftrace_disabled))
8360		return;
8361
8362	/* Force update next time */
8363	saved_ftrace_func = NULL;
8364	/* ftrace_start_up is true if we want ftrace running */
8365	if (ftrace_start_up) {
8366		command = FTRACE_UPDATE_CALLS;
8367		if (ftrace_graph_active)
8368			command |= FTRACE_START_FUNC_RET;
8369		ftrace_startup_enable(command);
8370	}
8371}
8372
8373static void ftrace_shutdown_sysctl(void)
8374{
8375	int command;
8376
8377	if (unlikely(ftrace_disabled))
8378		return;
8379
8380	/* ftrace_start_up is true if ftrace is running */
8381	if (ftrace_start_up) {
8382		command = FTRACE_DISABLE_CALLS;
8383		if (ftrace_graph_active)
8384			command |= FTRACE_STOP_FUNC_RET;
8385		ftrace_run_update_code(command);
8386	}
8387}
8388#else
8389# define ftrace_startup_sysctl()       do { } while (0)
8390# define ftrace_shutdown_sysctl()      do { } while (0)
8391#endif /* CONFIG_DYNAMIC_FTRACE */
8392
8393static bool is_permanent_ops_registered(void)
8394{
8395	struct ftrace_ops *op;
8396
8397	do_for_each_ftrace_op(op, ftrace_ops_list) {
8398		if (op->flags & FTRACE_OPS_FL_PERMANENT)
8399			return true;
8400	} while_for_each_ftrace_op(op);
8401
8402	return false;
8403}
8404
8405static int
8406ftrace_enable_sysctl(struct ctl_table *table, int write,
8407		     void *buffer, size_t *lenp, loff_t *ppos)
8408{
8409	int ret = -ENODEV;
8410
8411	mutex_lock(&ftrace_lock);
8412
8413	if (unlikely(ftrace_disabled))
8414		goto out;
8415
8416	ret = proc_dointvec(table, write, buffer, lenp, ppos);
8417
8418	if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled))
8419		goto out;
8420
8421	if (ftrace_enabled) {
8422
8423		/* we are starting ftrace again */
8424		if (rcu_dereference_protected(ftrace_ops_list,
8425			lockdep_is_held(&ftrace_lock)) != &ftrace_list_end)
8426			update_ftrace_function();
8427
8428		ftrace_startup_sysctl();
8429
8430	} else {
8431		if (is_permanent_ops_registered()) {
8432			ftrace_enabled = true;
8433			ret = -EBUSY;
8434			goto out;
8435		}
8436
8437		/* stopping ftrace calls (just send to ftrace_stub) */
8438		ftrace_trace_function = ftrace_stub;
8439
8440		ftrace_shutdown_sysctl();
8441	}
8442
8443	last_ftrace_enabled = !!ftrace_enabled;
8444 out:
8445	mutex_unlock(&ftrace_lock);
8446	return ret;
8447}
8448
8449static struct ctl_table ftrace_sysctls[] = {
8450	{
8451		.procname       = "ftrace_enabled",
8452		.data           = &ftrace_enabled,
8453		.maxlen         = sizeof(int),
8454		.mode           = 0644,
8455		.proc_handler   = ftrace_enable_sysctl,
8456	},
8457	{}
8458};
8459
8460static int __init ftrace_sysctl_init(void)
8461{
8462	register_sysctl_init("kernel", ftrace_sysctls);
8463	return 0;
8464}
8465late_initcall(ftrace_sysctl_init);
8466#endif