1/*
   2 *  Kernel Probes (KProbes)
   3 *  kernel/kprobes.c
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License as published by
   7 * the Free Software Foundation; either version 2 of the License, or
   8 * (at your option) any later version.
   9 *
  10 * This program is distributed in the hope that it will be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 * GNU General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License
  16 * along with this program; if not, write to the Free Software
  17 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18 *
  19 * Copyright (C) IBM Corporation, 2002, 2004
  20 *
  21 * 2002-Oct	Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
  22 *		Probes initial implementation (includes suggestions from
  23 *		Rusty Russell).
  24 * 2004-Aug	Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with
  25 *		hlists and exceptions notifier as suggested by Andi Kleen.
  26 * 2004-July	Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
  27 *		interface to access function arguments.
  28 * 2004-Sep	Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes
  29 *		exceptions notifier to be first on the priority list.
  30 * 2005-May	Hien Nguyen <hien@us.ibm.com>, Jim Keniston
  31 *		<jkenisto@us.ibm.com> and Prasanna S Panchamukhi
  32 *		<prasanna@in.ibm.com> added function-return probes.
  33 */
  34#include <linux/kprobes.h>
  35#include <linux/hash.h>
  36#include <linux/init.h>
  37#include <linux/slab.h>
  38#include <linux/stddef.h>
  39#include <linux/export.h>
  40#include <linux/moduleloader.h>
  41#include <linux/kallsyms.h>
  42#include <linux/freezer.h>
  43#include <linux/seq_file.h>
  44#include <linux/debugfs.h>
  45#include <linux/sysctl.h>
  46#include <linux/kdebug.h>
  47#include <linux/memory.h>
  48#include <linux/ftrace.h>
  49#include <linux/cpu.h>
  50#include <linux/jump_label.h>
 
 
  51
  52#include <asm-generic/sections.h>
  53#include <asm/cacheflush.h>
  54#include <asm/errno.h>
  55#include <asm/uaccess.h>
  56
  57#define KPROBE_HASH_BITS 6
  58#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
  59
  60
  61/*
  62 * Some oddball architectures like 64bit powerpc have function descriptors
  63 * so this must be overridable.
  64 */
  65#ifndef kprobe_lookup_name
  66#define kprobe_lookup_name(name, addr) \
  67	addr = ((kprobe_opcode_t *)(kallsyms_lookup_name(name)))
  68#endif
  69
  70static int kprobes_initialized;
 
 
 
 
 
  71static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
  72static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
  73
  74/* NOTE: change this value only with kprobe_mutex held */
  75static bool kprobes_all_disarmed;
  76
  77/* This protects kprobe_table and optimizing_list */
  78static DEFINE_MUTEX(kprobe_mutex);
  79static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
  80static struct {
  81	raw_spinlock_t lock ____cacheline_aligned_in_smp;
  82} kretprobe_table_locks[KPROBE_TABLE_SIZE];
  83
  84static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
 
  85{
  86	return &(kretprobe_table_locks[hash].lock);
  87}
  88
  89/*
  90 * Normally, functions that we'd want to prohibit kprobes in, are marked
  91 * __kprobes. But, there are cases where such functions already belong to
  92 * a different section (__sched for preempt_schedule)
  93 *
  94 * For such cases, we now have a blacklist
  95 */
  96static struct kprobe_blackpoint kprobe_blacklist[] = {
  97	{"preempt_schedule",},
  98	{"native_get_debugreg",},
  99	{"irq_entries_start",},
 100	{"common_interrupt",},
 101	{"mcount",},	/* mcount can be called from everywhere */
 102	{NULL}    /* Terminator */
 103};
 104
 105#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
 106/*
 107 * kprobe->ainsn.insn points to the copy of the instruction to be
 108 * single-stepped. x86_64, POWER4 and above have no-exec support and
 109 * stepping on the instruction on a vmalloced/kmalloced/data page
 110 * is a recipe for disaster
 111 */
 112struct kprobe_insn_page {
 113	struct list_head list;
 114	kprobe_opcode_t *insns;		/* Page of instruction slots */
 
 115	int nused;
 116	int ngarbage;
 117	char slot_used[];
 118};
 119
 120#define KPROBE_INSN_PAGE_SIZE(slots)			\
 121	(offsetof(struct kprobe_insn_page, slot_used) +	\
 122	 (sizeof(char) * (slots)))
 123
 124struct kprobe_insn_cache {
 125	struct list_head pages;	/* list of kprobe_insn_page */
 126	size_t insn_size;	/* size of instruction slot */
 127	int nr_garbage;
 128};
 129
 130static int slots_per_page(struct kprobe_insn_cache *c)
 131{
 132	return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t));
 133}
 134
 135enum kprobe_slot_state {
 136	SLOT_CLEAN = 0,
 137	SLOT_DIRTY = 1,
 138	SLOT_USED = 2,
 139};
 140
 141static DEFINE_MUTEX(kprobe_insn_mutex);	/* Protects kprobe_insn_slots */
 142static struct kprobe_insn_cache kprobe_insn_slots = {
 
 
 
 
 
 
 
 
 
 
 
 
 
 143	.pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
 144	.insn_size = MAX_INSN_SIZE,
 145	.nr_garbage = 0,
 146};
 147static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c);
 148
 149/**
 150 * __get_insn_slot() - Find a slot on an executable page for an instruction.
 151 * We allocate an executable page if there's no room on existing ones.
 152 */
 153static kprobe_opcode_t __kprobes *__get_insn_slot(struct kprobe_insn_cache *c)
 154{
 155	struct kprobe_insn_page *kip;
 
 156
 
 
 157 retry:
 158	list_for_each_entry(kip, &c->pages, list) {
 
 159		if (kip->nused < slots_per_page(c)) {
 160			int i;
 161			for (i = 0; i < slots_per_page(c); i++) {
 162				if (kip->slot_used[i] == SLOT_CLEAN) {
 163					kip->slot_used[i] = SLOT_USED;
 164					kip->nused++;
 165					return kip->insns + (i * c->insn_size);
 
 
 166				}
 167			}
 168			/* kip->nused is broken. Fix it. */
 169			kip->nused = slots_per_page(c);
 170			WARN_ON(1);
 171		}
 172	}
 
 173
 174	/* If there are any garbage slots, collect it and try again. */
 175	if (c->nr_garbage && collect_garbage_slots(c) == 0)
 176		goto retry;
 177
 178	/* All out of space.  Need to allocate a new page. */
 179	kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL);
 180	if (!kip)
 181		return NULL;
 182
 183	/*
 184	 * Use module_alloc so this page is within +/- 2GB of where the
 185	 * kernel image and loaded module images reside. This is required
 186	 * so x86_64 can correctly handle the %rip-relative fixups.
 187	 */
 188	kip->insns = module_alloc(PAGE_SIZE);
 189	if (!kip->insns) {
 190		kfree(kip);
 191		return NULL;
 192	}
 193	INIT_LIST_HEAD(&kip->list);
 194	memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
 195	kip->slot_used[0] = SLOT_USED;
 196	kip->nused = 1;
 197	kip->ngarbage = 0;
 198	list_add(&kip->list, &c->pages);
 199	return kip->insns;
 200}
 201
 202
 203kprobe_opcode_t __kprobes *get_insn_slot(void)
 204{
 205	kprobe_opcode_t *ret = NULL;
 206
 207	mutex_lock(&kprobe_insn_mutex);
 208	ret = __get_insn_slot(&kprobe_insn_slots);
 209	mutex_unlock(&kprobe_insn_mutex);
 210
 211	return ret;
 212}
 213
 214/* Return 1 if all garbages are collected, otherwise 0. */
 215static int __kprobes collect_one_slot(struct kprobe_insn_page *kip, int idx)
 216{
 217	kip->slot_used[idx] = SLOT_CLEAN;
 218	kip->nused--;
 219	if (kip->nused == 0) {
 220		/*
 221		 * Page is no longer in use.  Free it unless
 222		 * it's the last one.  We keep the last one
 223		 * so as not to have to set it up again the
 224		 * next time somebody inserts a probe.
 225		 */
 226		if (!list_is_singular(&kip->list)) {
 227			list_del(&kip->list);
 228			module_free(NULL, kip->insns);
 
 
 
 
 
 
 
 
 229			kfree(kip);
 230		}
 231		return 1;
 232	}
 233	return 0;
 234}
 235
 236static int __kprobes collect_garbage_slots(struct kprobe_insn_cache *c)
 237{
 238	struct kprobe_insn_page *kip, *next;
 239
 240	/* Ensure no-one is interrupted on the garbages */
 241	synchronize_sched();
 242
 243	list_for_each_entry_safe(kip, next, &c->pages, list) {
 244		int i;
 245		if (kip->ngarbage == 0)
 246			continue;
 247		kip->ngarbage = 0;	/* we will collect all garbages */
 248		for (i = 0; i < slots_per_page(c); i++) {
 249			if (kip->slot_used[i] == SLOT_DIRTY &&
 250			    collect_one_slot(kip, i))
 251				break;
 252		}
 253	}
 254	c->nr_garbage = 0;
 255	return 0;
 256}
 257
 258static void __kprobes __free_insn_slot(struct kprobe_insn_cache *c,
 259				       kprobe_opcode_t *slot, int dirty)
 260{
 261	struct kprobe_insn_page *kip;
 
 262
 263	list_for_each_entry(kip, &c->pages, list) {
 264		long idx = ((long)slot - (long)kip->insns) /
 265				(c->insn_size * sizeof(kprobe_opcode_t));
 266		if (idx >= 0 && idx < slots_per_page(c)) {
 267			WARN_ON(kip->slot_used[idx] != SLOT_USED);
 268			if (dirty) {
 269				kip->slot_used[idx] = SLOT_DIRTY;
 270				kip->ngarbage++;
 271				if (++c->nr_garbage > slots_per_page(c))
 272					collect_garbage_slots(c);
 273			} else
 274				collect_one_slot(kip, idx);
 275			return;
 276		}
 277	}
 278	/* Could not free this slot. */
 279	WARN_ON(1);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 280}
 281
 282void __kprobes free_insn_slot(kprobe_opcode_t * slot, int dirty)
 
 
 
 
 
 283{
 284	mutex_lock(&kprobe_insn_mutex);
 285	__free_insn_slot(&kprobe_insn_slots, slot, dirty);
 286	mutex_unlock(&kprobe_insn_mutex);
 
 
 
 
 
 
 
 
 
 
 
 287}
 288#ifdef CONFIG_OPTPROBES
 289/* For optimized_kprobe buffer */
 290static DEFINE_MUTEX(kprobe_optinsn_mutex); /* Protects kprobe_optinsn_slots */
 291static struct kprobe_insn_cache kprobe_optinsn_slots = {
 292	.pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
 293	/* .insn_size is initialized later */
 294	.nr_garbage = 0,
 295};
 296/* Get a slot for optimized_kprobe buffer */
 297kprobe_opcode_t __kprobes *get_optinsn_slot(void)
 298{
 299	kprobe_opcode_t *ret = NULL;
 
 300
 301	mutex_lock(&kprobe_optinsn_mutex);
 302	ret = __get_insn_slot(&kprobe_optinsn_slots);
 303	mutex_unlock(&kprobe_optinsn_mutex);
 
 
 
 
 
 
 
 
 304
 305	return ret;
 306}
 307
 308void __kprobes free_optinsn_slot(kprobe_opcode_t * slot, int dirty)
 
 
 
 
 
 
 309{
 310	mutex_lock(&kprobe_optinsn_mutex);
 311	__free_insn_slot(&kprobe_optinsn_slots, slot, dirty);
 312	mutex_unlock(&kprobe_optinsn_mutex);
 313}
 
 
 
 
 
 
 
 
 
 
 
 314#endif
 315#endif
 316
 317/* We have preemption disabled.. so it is safe to use __ versions */
 318static inline void set_kprobe_instance(struct kprobe *kp)
 319{
 320	__this_cpu_write(kprobe_instance, kp);
 321}
 322
 323static inline void reset_kprobe_instance(void)
 324{
 325	__this_cpu_write(kprobe_instance, NULL);
 326}
 327
 328/*
 329 * This routine is called either:
 330 * 	- under the kprobe_mutex - during kprobe_[un]register()
 331 * 				OR
 332 * 	- with preemption disabled - from arch/xxx/kernel/kprobes.c
 333 */
 334struct kprobe __kprobes *get_kprobe(void *addr)
 335{
 336	struct hlist_head *head;
 337	struct hlist_node *node;
 338	struct kprobe *p;
 339
 340	head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)];
 341	hlist_for_each_entry_rcu(p, node, head, hlist) {
 
 342		if (p->addr == addr)
 343			return p;
 344	}
 345
 346	return NULL;
 347}
 
 348
 349static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
 350
 351/* Return true if the kprobe is an aggregator */
 352static inline int kprobe_aggrprobe(struct kprobe *p)
 353{
 354	return p->pre_handler == aggr_pre_handler;
 355}
 356
 357/* Return true(!0) if the kprobe is unused */
 358static inline int kprobe_unused(struct kprobe *p)
 359{
 360	return kprobe_aggrprobe(p) && kprobe_disabled(p) &&
 361	       list_empty(&p->list);
 362}
 363
 364/*
 365 * Keep all fields in the kprobe consistent
 366 */
 367static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
 368{
 369	memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t));
 370	memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn));
 371}
 372
 373#ifdef CONFIG_OPTPROBES
 374/* NOTE: change this value only with kprobe_mutex held */
 375static bool kprobes_allow_optimization;
 376
 377/*
 378 * Call all pre_handler on the list, but ignores its return value.
 379 * This must be called from arch-dep optimized caller.
 380 */
 381void __kprobes opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
 382{
 383	struct kprobe *kp;
 384
 385	list_for_each_entry_rcu(kp, &p->list, list) {
 386		if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
 387			set_kprobe_instance(kp);
 388			kp->pre_handler(kp, regs);
 389		}
 390		reset_kprobe_instance();
 391	}
 392}
 
 393
 394/* Free optimized instructions and optimized_kprobe */
 395static __kprobes void free_aggr_kprobe(struct kprobe *p)
 396{
 397	struct optimized_kprobe *op;
 398
 399	op = container_of(p, struct optimized_kprobe, kp);
 400	arch_remove_optimized_kprobe(op);
 401	arch_remove_kprobe(p);
 402	kfree(op);
 403}
 404
 405/* Return true(!0) if the kprobe is ready for optimization. */
 406static inline int kprobe_optready(struct kprobe *p)
 407{
 408	struct optimized_kprobe *op;
 409
 410	if (kprobe_aggrprobe(p)) {
 411		op = container_of(p, struct optimized_kprobe, kp);
 412		return arch_prepared_optinsn(&op->optinsn);
 413	}
 414
 415	return 0;
 416}
 417
 418/* Return true(!0) if the kprobe is disarmed. Note: p must be on hash list */
 419static inline int kprobe_disarmed(struct kprobe *p)
 420{
 421	struct optimized_kprobe *op;
 422
 423	/* If kprobe is not aggr/opt probe, just return kprobe is disabled */
 424	if (!kprobe_aggrprobe(p))
 425		return kprobe_disabled(p);
 426
 427	op = container_of(p, struct optimized_kprobe, kp);
 428
 429	return kprobe_disabled(p) && list_empty(&op->list);
 430}
 431
 432/* Return true(!0) if the probe is queued on (un)optimizing lists */
 433static int __kprobes kprobe_queued(struct kprobe *p)
 434{
 435	struct optimized_kprobe *op;
 436
 437	if (kprobe_aggrprobe(p)) {
 438		op = container_of(p, struct optimized_kprobe, kp);
 439		if (!list_empty(&op->list))
 440			return 1;
 441	}
 442	return 0;
 443}
 444
 445/*
 446 * Return an optimized kprobe whose optimizing code replaces
 447 * instructions including addr (exclude breakpoint).
 448 */
 449static struct kprobe *__kprobes get_optimized_kprobe(unsigned long addr)
 450{
 451	int i;
 452	struct kprobe *p = NULL;
 453	struct optimized_kprobe *op;
 454
 455	/* Don't check i == 0, since that is a breakpoint case. */
 456	for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH; i++)
 457		p = get_kprobe((void *)(addr - i));
 458
 459	if (p && kprobe_optready(p)) {
 460		op = container_of(p, struct optimized_kprobe, kp);
 461		if (arch_within_optimized_kprobe(op, addr))
 462			return p;
 463	}
 464
 465	return NULL;
 466}
 467
 468/* Optimization staging list, protected by kprobe_mutex */
 469static LIST_HEAD(optimizing_list);
 470static LIST_HEAD(unoptimizing_list);
 
 471
 472static void kprobe_optimizer(struct work_struct *work);
 473static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
 474static DECLARE_COMPLETION(optimizer_comp);
 475#define OPTIMIZE_DELAY 5
 476
 477/*
 478 * Optimize (replace a breakpoint with a jump) kprobes listed on
 479 * optimizing_list.
 480 */
 481static __kprobes void do_optimize_kprobes(void)
 482{
 483	/* Optimization never be done when disarmed */
 484	if (kprobes_all_disarmed || !kprobes_allow_optimization ||
 485	    list_empty(&optimizing_list))
 486		return;
 487
 488	/*
 489	 * The optimization/unoptimization refers online_cpus via
 490	 * stop_machine() and cpu-hotplug modifies online_cpus.
 491	 * And same time, text_mutex will be held in cpu-hotplug and here.
 492	 * This combination can cause a deadlock (cpu-hotplug try to lock
 493	 * text_mutex but stop_machine can not be done because online_cpus
 494	 * has been changed)
 495	 * To avoid this deadlock, we need to call get_online_cpus()
 496	 * for preventing cpu-hotplug outside of text_mutex locking.
 497	 */
 498	get_online_cpus();
 499	mutex_lock(&text_mutex);
 
 
 
 
 
 500	arch_optimize_kprobes(&optimizing_list);
 501	mutex_unlock(&text_mutex);
 502	put_online_cpus();
 503}
 504
 505/*
 506 * Unoptimize (replace a jump with a breakpoint and remove the breakpoint
 507 * if need) kprobes listed on unoptimizing_list.
 508 */
 509static __kprobes void do_unoptimize_kprobes(struct list_head *free_list)
 510{
 511	struct optimized_kprobe *op, *tmp;
 512
 
 
 
 
 513	/* Unoptimization must be done anytime */
 514	if (list_empty(&unoptimizing_list))
 515		return;
 516
 517	/* Ditto to do_optimize_kprobes */
 518	get_online_cpus();
 519	mutex_lock(&text_mutex);
 520	arch_unoptimize_kprobes(&unoptimizing_list, free_list);
 521	/* Loop free_list for disarming */
 522	list_for_each_entry_safe(op, tmp, free_list, list) {
 
 
 523		/* Disarm probes if marked disabled */
 524		if (kprobe_disabled(&op->kp))
 525			arch_disarm_kprobe(&op->kp);
 526		if (kprobe_unused(&op->kp)) {
 527			/*
 528			 * Remove unused probes from hash list. After waiting
 529			 * for synchronization, these probes are reclaimed.
 530			 * (reclaiming is done by do_free_cleaned_kprobes.)
 531			 */
 532			hlist_del_rcu(&op->kp.hlist);
 533		} else
 534			list_del_init(&op->list);
 535	}
 536	mutex_unlock(&text_mutex);
 537	put_online_cpus();
 538}
 539
 540/* Reclaim all kprobes on the free_list */
 541static __kprobes void do_free_cleaned_kprobes(struct list_head *free_list)
 542{
 543	struct optimized_kprobe *op, *tmp;
 544
 545	list_for_each_entry_safe(op, tmp, free_list, list) {
 546		BUG_ON(!kprobe_unused(&op->kp));
 547		list_del_init(&op->list);
 
 
 
 
 
 
 
 548		free_aggr_kprobe(&op->kp);
 549	}
 550}
 551
 552/* Start optimizer after OPTIMIZE_DELAY passed */
 553static __kprobes void kick_kprobe_optimizer(void)
 554{
 555	if (!delayed_work_pending(&optimizing_work))
 556		schedule_delayed_work(&optimizing_work, OPTIMIZE_DELAY);
 557}
 558
 559/* Kprobe jump optimizer */
 560static __kprobes void kprobe_optimizer(struct work_struct *work)
 561{
 562	LIST_HEAD(free_list);
 563
 564	/* Lock modules while optimizing kprobes */
 565	mutex_lock(&module_mutex);
 566	mutex_lock(&kprobe_mutex);
 
 
 567
 568	/*
 569	 * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
 570	 * kprobes before waiting for quiesence period.
 571	 */
 572	do_unoptimize_kprobes(&free_list);
 573
 574	/*
 575	 * Step 2: Wait for quiesence period to ensure all running interrupts
 576	 * are done. Because optprobe may modify multiple instructions
 577	 * there is a chance that Nth instruction is interrupted. In that
 578	 * case, running interrupt can return to 2nd-Nth byte of jump
 579	 * instruction. This wait is for avoiding it.
 
 
 580	 */
 581	synchronize_sched();
 582
 583	/* Step 3: Optimize kprobes after quiesence period */
 584	do_optimize_kprobes();
 585
 586	/* Step 4: Free cleaned kprobes after quiesence period */
 587	do_free_cleaned_kprobes(&free_list);
 588
 589	mutex_unlock(&kprobe_mutex);
 590	mutex_unlock(&module_mutex);
 591
 592	/* Step 5: Kick optimizer again if needed */
 593	if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
 594		kick_kprobe_optimizer();
 595	else
 596		/* Wake up all waiters */
 597		complete_all(&optimizer_comp);
 598}
 599
 600/* Wait for completing optimization and unoptimization */
 601static __kprobes void wait_for_kprobe_optimizer(void)
 602{
 603	if (delayed_work_pending(&optimizing_work))
 604		wait_for_completion(&optimizer_comp);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 605}
 606
 607/* Optimize kprobe if p is ready to be optimized */
 608static __kprobes void optimize_kprobe(struct kprobe *p)
 609{
 610	struct optimized_kprobe *op;
 611
 612	/* Check if the kprobe is disabled or not ready for optimization. */
 613	if (!kprobe_optready(p) || !kprobes_allow_optimization ||
 614	    (kprobe_disabled(p) || kprobes_all_disarmed))
 615		return;
 616
 617	/* Both of break_handler and post_handler are not supported. */
 618	if (p->break_handler || p->post_handler)
 619		return;
 620
 621	op = container_of(p, struct optimized_kprobe, kp);
 622
 623	/* Check there is no other kprobes at the optimized instructions */
 624	if (arch_check_optimized_kprobe(op) < 0)
 625		return;
 626
 627	/* Check if it is already optimized. */
 628	if (op->kp.flags & KPROBE_FLAG_OPTIMIZED)
 
 
 
 
 629		return;
 
 630	op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
 631
 632	if (!list_empty(&op->list))
 633		/* This is under unoptimizing. Just dequeue the probe */
 634		list_del_init(&op->list);
 635	else {
 636		list_add(&op->list, &optimizing_list);
 637		kick_kprobe_optimizer();
 638	}
 639}
 640
 641/* Short cut to direct unoptimizing */
 642static __kprobes void force_unoptimize_kprobe(struct optimized_kprobe *op)
 643{
 644	get_online_cpus();
 645	arch_unoptimize_kprobe(op);
 646	put_online_cpus();
 647	if (kprobe_disabled(&op->kp))
 648		arch_disarm_kprobe(&op->kp);
 649}
 650
 651/* Unoptimize a kprobe if p is optimized */
 652static __kprobes void unoptimize_kprobe(struct kprobe *p, bool force)
 653{
 654	struct optimized_kprobe *op;
 655
 656	if (!kprobe_aggrprobe(p) || kprobe_disarmed(p))
 657		return; /* This is not an optprobe nor optimized */
 658
 659	op = container_of(p, struct optimized_kprobe, kp);
 660	if (!kprobe_optimized(p)) {
 661		/* Unoptimized or unoptimizing case */
 662		if (force && !list_empty(&op->list)) {
 663			/*
 664			 * Only if this is unoptimizing kprobe and forced,
 665			 * forcibly unoptimize it. (No need to unoptimize
 666			 * unoptimized kprobe again :)
 667			 */
 668			list_del_init(&op->list);
 669			force_unoptimize_kprobe(op);
 670		}
 671		return;
 672	}
 673
 674	op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
 675	if (!list_empty(&op->list)) {
 676		/* Dequeue from the optimization queue */
 677		list_del_init(&op->list);
 
 
 
 
 
 
 
 
 
 
 
 
 
 678		return;
 679	}
 
 680	/* Optimized kprobe case */
 681	if (force)
 682		/* Forcibly update the code: this is a special case */
 683		force_unoptimize_kprobe(op);
 684	else {
 685		list_add(&op->list, &unoptimizing_list);
 686		kick_kprobe_optimizer();
 687	}
 688}
 689
 690/* Cancel unoptimizing for reusing */
 691static void reuse_unused_kprobe(struct kprobe *ap)
 692{
 693	struct optimized_kprobe *op;
 694
 695	BUG_ON(!kprobe_unused(ap));
 696	/*
 697	 * Unused kprobe MUST be on the way of delayed unoptimizing (means
 698	 * there is still a relative jump) and disabled.
 699	 */
 700	op = container_of(ap, struct optimized_kprobe, kp);
 701	if (unlikely(list_empty(&op->list)))
 702		printk(KERN_WARNING "Warning: found a stray unused "
 703			"aggrprobe@%p\n", ap->addr);
 704	/* Enable the probe again */
 705	ap->flags &= ~KPROBE_FLAG_DISABLED;
 706	/* Optimize it again (remove from op->list) */
 707	BUG_ON(!kprobe_optready(ap));
 
 
 708	optimize_kprobe(ap);
 
 709}
 710
 711/* Remove optimized instructions */
 712static void __kprobes kill_optimized_kprobe(struct kprobe *p)
 713{
 714	struct optimized_kprobe *op;
 715
 716	op = container_of(p, struct optimized_kprobe, kp);
 717	if (!list_empty(&op->list))
 718		/* Dequeue from the (un)optimization queue */
 719		list_del_init(&op->list);
 720
 721	op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
 
 
 
 
 
 
 
 
 
 
 
 
 722	/* Don't touch the code, because it is already freed. */
 723	arch_remove_optimized_kprobe(op);
 724}
 725
 
 
 
 
 
 
 
 726/* Try to prepare optimized instructions */
 727static __kprobes void prepare_optimized_kprobe(struct kprobe *p)
 728{
 729	struct optimized_kprobe *op;
 730
 731	op = container_of(p, struct optimized_kprobe, kp);
 732	arch_prepare_optimized_kprobe(op);
 733}
 734
 735/* Allocate new optimized_kprobe and try to prepare optimized instructions */
 736static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
 737{
 738	struct optimized_kprobe *op;
 739
 740	op = kzalloc(sizeof(struct optimized_kprobe), GFP_KERNEL);
 741	if (!op)
 742		return NULL;
 743
 744	INIT_LIST_HEAD(&op->list);
 745	op->kp.addr = p->addr;
 746	arch_prepare_optimized_kprobe(op);
 747
 748	return &op->kp;
 749}
 750
 751static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
 752
 753/*
 754 * Prepare an optimized_kprobe and optimize it
 755 * NOTE: p must be a normal registered kprobe
 756 */
 757static __kprobes void try_to_optimize_kprobe(struct kprobe *p)
 758{
 759	struct kprobe *ap;
 760	struct optimized_kprobe *op;
 761
 
 
 
 
 
 
 
 
 
 762	ap = alloc_aggr_kprobe(p);
 763	if (!ap)
 764		return;
 765
 766	op = container_of(ap, struct optimized_kprobe, kp);
 767	if (!arch_prepared_optinsn(&op->optinsn)) {
 768		/* If failed to setup optimizing, fallback to kprobe */
 769		arch_remove_optimized_kprobe(op);
 770		kfree(op);
 771		return;
 772	}
 773
 774	init_aggr_kprobe(ap, p);
 775	optimize_kprobe(ap);
 
 
 
 
 
 776}
 777
 778#ifdef CONFIG_SYSCTL
 779/* This should be called with kprobe_mutex locked */
 780static void __kprobes optimize_all_kprobes(void)
 781{
 782	struct hlist_head *head;
 783	struct hlist_node *node;
 784	struct kprobe *p;
 785	unsigned int i;
 786
 
 787	/* If optimization is already allowed, just return */
 788	if (kprobes_allow_optimization)
 789		return;
 790
 
 791	kprobes_allow_optimization = true;
 792	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
 793		head = &kprobe_table[i];
 794		hlist_for_each_entry_rcu(p, node, head, hlist)
 795			if (!kprobe_disabled(p))
 796				optimize_kprobe(p);
 797	}
 
 798	printk(KERN_INFO "Kprobes globally optimized\n");
 
 
 799}
 800
 801/* This should be called with kprobe_mutex locked */
 802static void __kprobes unoptimize_all_kprobes(void)
 803{
 804	struct hlist_head *head;
 805	struct hlist_node *node;
 806	struct kprobe *p;
 807	unsigned int i;
 808
 
 809	/* If optimization is already prohibited, just return */
 810	if (!kprobes_allow_optimization)
 
 811		return;
 
 812
 
 813	kprobes_allow_optimization = false;
 814	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
 815		head = &kprobe_table[i];
 816		hlist_for_each_entry_rcu(p, node, head, hlist) {
 817			if (!kprobe_disabled(p))
 818				unoptimize_kprobe(p, false);
 819		}
 820	}
 
 
 
 821	/* Wait for unoptimizing completion */
 822	wait_for_kprobe_optimizer();
 823	printk(KERN_INFO "Kprobes globally unoptimized\n");
 824}
 825
 
 826int sysctl_kprobes_optimization;
 827int proc_kprobes_optimization_handler(struct ctl_table *table, int write,
 828				      void __user *buffer, size_t *length,
 829				      loff_t *ppos)
 830{
 831	int ret;
 832
 833	mutex_lock(&kprobe_mutex);
 834	sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0;
 835	ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
 836
 837	if (sysctl_kprobes_optimization)
 838		optimize_all_kprobes();
 839	else
 840		unoptimize_all_kprobes();
 841	mutex_unlock(&kprobe_mutex);
 842
 843	return ret;
 844}
 845#endif /* CONFIG_SYSCTL */
 846
 847/* Put a breakpoint for a probe. Must be called with text_mutex locked */
 848static void __kprobes __arm_kprobe(struct kprobe *p)
 849{
 850	struct kprobe *_p;
 851
 852	/* Check collision with other optimized kprobes */
 853	_p = get_optimized_kprobe((unsigned long)p->addr);
 854	if (unlikely(_p))
 855		/* Fallback to unoptimized kprobe */
 856		unoptimize_kprobe(_p, true);
 857
 858	arch_arm_kprobe(p);
 859	optimize_kprobe(p);	/* Try to optimize (add kprobe to a list) */
 860}
 861
 862/* Remove the breakpoint of a probe. Must be called with text_mutex locked */
 863static void __kprobes __disarm_kprobe(struct kprobe *p, bool reopt)
 864{
 865	struct kprobe *_p;
 866
 867	unoptimize_kprobe(p, false);	/* Try to unoptimize */
 
 868
 869	if (!kprobe_queued(p)) {
 870		arch_disarm_kprobe(p);
 871		/* If another kprobe was blocked, optimize it. */
 872		_p = get_optimized_kprobe((unsigned long)p->addr);
 873		if (unlikely(_p) && reopt)
 874			optimize_kprobe(_p);
 875	}
 876	/* TODO: reoptimize others after unoptimized this probe */
 877}
 878
 879#else /* !CONFIG_OPTPROBES */
 880
 881#define optimize_kprobe(p)			do {} while (0)
 882#define unoptimize_kprobe(p, f)			do {} while (0)
 883#define kill_optimized_kprobe(p)		do {} while (0)
 884#define prepare_optimized_kprobe(p)		do {} while (0)
 885#define try_to_optimize_kprobe(p)		do {} while (0)
 886#define __arm_kprobe(p)				arch_arm_kprobe(p)
 887#define __disarm_kprobe(p, o)			arch_disarm_kprobe(p)
 888#define kprobe_disarmed(p)			kprobe_disabled(p)
 889#define wait_for_kprobe_optimizer()		do {} while (0)
 890
 891/* There should be no unused kprobes can be reused without optimization */
 892static void reuse_unused_kprobe(struct kprobe *ap)
 893{
 
 
 
 
 
 
 894	printk(KERN_ERR "Error: There should be no unused kprobe here.\n");
 895	BUG_ON(kprobe_unused(ap));
 896}
 897
 898static __kprobes void free_aggr_kprobe(struct kprobe *p)
 899{
 900	arch_remove_kprobe(p);
 901	kfree(p);
 902}
 903
 904static __kprobes struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
 905{
 906	return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
 907}
 908#endif /* CONFIG_OPTPROBES */
 909
 910/* Arm a kprobe with text_mutex */
 911static void __kprobes arm_kprobe(struct kprobe *kp)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 912{
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 913	/*
 914	 * Here, since __arm_kprobe() doesn't use stop_machine(),
 915	 * this doesn't cause deadlock on text_mutex. So, we don't
 916	 * need get_online_cpus().
 917	 */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 918	mutex_lock(&text_mutex);
 919	__arm_kprobe(kp);
 920	mutex_unlock(&text_mutex);
 
 
 
 921}
 922
 923/* Disarm a kprobe with text_mutex */
 924static void __kprobes disarm_kprobe(struct kprobe *kp)
 925{
 926	/* Ditto */
 
 
 
 927	mutex_lock(&text_mutex);
 928	__disarm_kprobe(kp, true);
 929	mutex_unlock(&text_mutex);
 
 
 
 930}
 931
 932/*
 933 * Aggregate handlers for multiple kprobes support - these handlers
 934 * take care of invoking the individual kprobe handlers on p->list
 935 */
 936static int __kprobes aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
 937{
 938	struct kprobe *kp;
 939
 940	list_for_each_entry_rcu(kp, &p->list, list) {
 941		if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
 942			set_kprobe_instance(kp);
 943			if (kp->pre_handler(kp, regs))
 944				return 1;
 945		}
 946		reset_kprobe_instance();
 947	}
 948	return 0;
 949}
 
 950
 951static void __kprobes aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
 952					unsigned long flags)
 953{
 954	struct kprobe *kp;
 955
 956	list_for_each_entry_rcu(kp, &p->list, list) {
 957		if (kp->post_handler && likely(!kprobe_disabled(kp))) {
 958			set_kprobe_instance(kp);
 959			kp->post_handler(kp, regs, flags);
 960			reset_kprobe_instance();
 961		}
 962	}
 963}
 964
 965static int __kprobes aggr_fault_handler(struct kprobe *p, struct pt_regs *regs,
 966					int trapnr)
 967{
 968	struct kprobe *cur = __this_cpu_read(kprobe_instance);
 969
 970	/*
 971	 * if we faulted "during" the execution of a user specified
 972	 * probe handler, invoke just that probe's fault handler
 973	 */
 974	if (cur && cur->fault_handler) {
 975		if (cur->fault_handler(cur, regs, trapnr))
 976			return 1;
 977	}
 978	return 0;
 979}
 980
 981static int __kprobes aggr_break_handler(struct kprobe *p, struct pt_regs *regs)
 982{
 983	struct kprobe *cur = __this_cpu_read(kprobe_instance);
 984	int ret = 0;
 985
 986	if (cur && cur->break_handler) {
 987		if (cur->break_handler(cur, regs))
 988			ret = 1;
 989	}
 990	reset_kprobe_instance();
 991	return ret;
 992}
 993
 994/* Walks the list and increments nmissed count for multiprobe case */
 995void __kprobes kprobes_inc_nmissed_count(struct kprobe *p)
 996{
 997	struct kprobe *kp;
 998	if (!kprobe_aggrprobe(p)) {
 999		p->nmissed++;
1000	} else {
1001		list_for_each_entry_rcu(kp, &p->list, list)
1002			kp->nmissed++;
1003	}
1004	return;
1005}
 
1006
1007void __kprobes recycle_rp_inst(struct kretprobe_instance *ri,
1008				struct hlist_head *head)
1009{
1010	struct kretprobe *rp = ri->rp;
1011
1012	/* remove rp inst off the rprobe_inst_table */
1013	hlist_del(&ri->hlist);
1014	INIT_HLIST_NODE(&ri->hlist);
1015	if (likely(rp)) {
1016		raw_spin_lock(&rp->lock);
1017		hlist_add_head(&ri->hlist, &rp->free_instances);
1018		raw_spin_unlock(&rp->lock);
1019	} else
1020		/* Unregistering */
1021		hlist_add_head(&ri->hlist, head);
1022}
 
1023
1024void __kprobes kretprobe_hash_lock(struct task_struct *tsk,
1025			 struct hlist_head **head, unsigned long *flags)
1026__acquires(hlist_lock)
1027{
1028	unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
1029	raw_spinlock_t *hlist_lock;
1030
1031	*head = &kretprobe_inst_table[hash];
1032	hlist_lock = kretprobe_table_lock_ptr(hash);
1033	raw_spin_lock_irqsave(hlist_lock, *flags);
 
1034}
 
1035
1036static void __kprobes kretprobe_table_lock(unsigned long hash,
1037	unsigned long *flags)
1038__acquires(hlist_lock)
1039{
1040	raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
1041	raw_spin_lock_irqsave(hlist_lock, *flags);
1042}
1043
1044void __kprobes kretprobe_hash_unlock(struct task_struct *tsk,
1045	unsigned long *flags)
1046__releases(hlist_lock)
1047{
1048	unsigned long hash = hash_ptr(tsk, KPROBE_HASH_BITS);
1049	raw_spinlock_t *hlist_lock;
1050
1051	hlist_lock = kretprobe_table_lock_ptr(hash);
1052	raw_spin_unlock_irqrestore(hlist_lock, *flags);
 
 
1053}
1054
1055static void __kprobes kretprobe_table_unlock(unsigned long hash,
1056       unsigned long *flags)
1057__releases(hlist_lock)
1058{
1059	raw_spinlock_t *hlist_lock = kretprobe_table_lock_ptr(hash);
1060	raw_spin_unlock_irqrestore(hlist_lock, *flags);
1061}
1062
1063/*
1064 * This function is called from finish_task_switch when task tk becomes dead,
1065 * so that we can recycle any function-return probe instances associated
1066 * with this task. These left over instances represent probed functions
1067 * that have been called but will never return.
1068 */
1069void __kprobes kprobe_flush_task(struct task_struct *tk)
1070{
1071	struct kretprobe_instance *ri;
1072	struct hlist_head *head, empty_rp;
1073	struct hlist_node *node, *tmp;
1074	unsigned long hash, flags = 0;
1075
 
1076	if (unlikely(!kprobes_initialized))
1077		/* Early boot.  kretprobe_table_locks not yet initialized. */
1078		return;
1079
1080	INIT_HLIST_HEAD(&empty_rp);
1081	hash = hash_ptr(tk, KPROBE_HASH_BITS);
1082	head = &kretprobe_inst_table[hash];
1083	kretprobe_table_lock(hash, &flags);
1084	hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {
1085		if (ri->task == tk)
1086			recycle_rp_inst(ri, &empty_rp);
1087	}
1088	kretprobe_table_unlock(hash, &flags);
1089	hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {
1090		hlist_del(&ri->hlist);
1091		kfree(ri);
1092	}
 
 
1093}
 
1094
1095static inline void free_rp_inst(struct kretprobe *rp)
1096{
1097	struct kretprobe_instance *ri;
1098	struct hlist_node *pos, *next;
 
 
 
 
 
 
1099
1100	hlist_for_each_entry_safe(ri, pos, next, &rp->free_instances, hlist) {
1101		hlist_del(&ri->hlist);
1102		kfree(ri);
 
1103	}
1104}
1105
1106static void __kprobes cleanup_rp_inst(struct kretprobe *rp)
1107{
1108	unsigned long flags, hash;
1109	struct kretprobe_instance *ri;
1110	struct hlist_node *pos, *next;
1111	struct hlist_head *head;
1112
1113	/* No race here */
1114	for (hash = 0; hash < KPROBE_TABLE_SIZE; hash++) {
1115		kretprobe_table_lock(hash, &flags);
1116		head = &kretprobe_inst_table[hash];
1117		hlist_for_each_entry_safe(ri, pos, next, head, hlist) {
1118			if (ri->rp == rp)
1119				ri->rp = NULL;
1120		}
1121		kretprobe_table_unlock(hash, &flags);
1122	}
1123	free_rp_inst(rp);
1124}
1125
1126/*
1127* Add the new probe to ap->list. Fail if this is the
1128* second jprobe at the address - two jprobes can't coexist
1129*/
1130static int __kprobes add_new_kprobe(struct kprobe *ap, struct kprobe *p)
1131{
1132	BUG_ON(kprobe_gone(ap) || kprobe_gone(p));
1133
1134	if (p->break_handler || p->post_handler)
1135		unoptimize_kprobe(ap, true);	/* Fall back to normal kprobe */
1136
1137	if (p->break_handler) {
1138		if (ap->break_handler)
1139			return -EEXIST;
1140		list_add_tail_rcu(&p->list, &ap->list);
1141		ap->break_handler = aggr_break_handler;
1142	} else
1143		list_add_rcu(&p->list, &ap->list);
1144	if (p->post_handler && !ap->post_handler)
1145		ap->post_handler = aggr_post_handler;
1146
1147	if (kprobe_disabled(ap) && !kprobe_disabled(p)) {
1148		ap->flags &= ~KPROBE_FLAG_DISABLED;
1149		if (!kprobes_all_disarmed)
1150			/* Arm the breakpoint again. */
1151			__arm_kprobe(ap);
1152	}
1153	return 0;
1154}
1155
1156/*
1157 * Fill in the required fields of the "manager kprobe". Replace the
1158 * earlier kprobe in the hlist with the manager kprobe
1159 */
1160static void __kprobes init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
1161{
1162	/* Copy p's insn slot to ap */
1163	copy_kprobe(p, ap);
1164	flush_insn_slot(ap);
1165	ap->addr = p->addr;
1166	ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
1167	ap->pre_handler = aggr_pre_handler;
1168	ap->fault_handler = aggr_fault_handler;
1169	/* We don't care the kprobe which has gone. */
1170	if (p->post_handler && !kprobe_gone(p))
1171		ap->post_handler = aggr_post_handler;
1172	if (p->break_handler && !kprobe_gone(p))
1173		ap->break_handler = aggr_break_handler;
1174
1175	INIT_LIST_HEAD(&ap->list);
1176	INIT_HLIST_NODE(&ap->hlist);
1177
1178	list_add_rcu(&p->list, &ap->list);
1179	hlist_replace_rcu(&p->hlist, &ap->hlist);
1180}
1181
1182/*
1183 * This is the second or subsequent kprobe at the address - handle
1184 * the intricacies
1185 */
1186static int __kprobes register_aggr_kprobe(struct kprobe *orig_p,
1187					  struct kprobe *p)
1188{
1189	int ret = 0;
1190	struct kprobe *ap = orig_p;
1191
 
 
 
 
 
 
1192	if (!kprobe_aggrprobe(orig_p)) {
1193		/* If orig_p is not an aggr_kprobe, create new aggr_kprobe. */
1194		ap = alloc_aggr_kprobe(orig_p);
1195		if (!ap)
1196			return -ENOMEM;
 
 
1197		init_aggr_kprobe(ap, orig_p);
1198	} else if (kprobe_unused(ap))
1199		/* This probe is going to die. Rescue it */
1200		reuse_unused_kprobe(ap);
 
 
 
1201
1202	if (kprobe_gone(ap)) {
1203		/*
1204		 * Attempting to insert new probe at the same location that
1205		 * had a probe in the module vaddr area which already
1206		 * freed. So, the instruction slot has already been
1207		 * released. We need a new slot for the new probe.
1208		 */
1209		ret = arch_prepare_kprobe(ap);
1210		if (ret)
1211			/*
1212			 * Even if fail to allocate new slot, don't need to
1213			 * free aggr_probe. It will be used next time, or
1214			 * freed by unregister_kprobe.
1215			 */
1216			return ret;
1217
1218		/* Prepare optimized instructions if possible. */
1219		prepare_optimized_kprobe(ap);
1220
1221		/*
1222		 * Clear gone flag to prevent allocating new slot again, and
1223		 * set disabled flag because it is not armed yet.
1224		 */
1225		ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
1226			    | KPROBE_FLAG_DISABLED;
1227	}
1228
1229	/* Copy ap's insn slot to p */
1230	copy_kprobe(ap, p);
1231	return add_new_kprobe(ap, p);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1232}
1233
1234static int __kprobes in_kprobes_functions(unsigned long addr)
1235{
1236	struct kprobe_blackpoint *kb;
 
 
 
1237
1238	if (addr >= (unsigned long)__kprobes_text_start &&
1239	    addr < (unsigned long)__kprobes_text_end)
1240		return -EINVAL;
 
 
 
1241	/*
1242	 * If there exists a kprobe_blacklist, verify and
1243	 * fail any probe registration in the prohibited area
1244	 */
1245	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
1246		if (kb->start_addr) {
1247			if (addr >= kb->start_addr &&
1248			    addr < (kb->start_addr + kb->range))
1249				return -EINVAL;
1250		}
1251	}
1252	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1253}
1254
1255/*
1256 * If we have a symbol_name argument, look it up and add the offset field
1257 * to it. This way, we can specify a relative address to a symbol.
1258 * This returns encoded errors if it fails to look up symbol or invalid
1259 * combination of parameters.
1260 */
1261static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p)
 
1262{
1263	kprobe_opcode_t *addr = p->addr;
1264
1265	if ((p->symbol_name && p->addr) ||
1266	    (!p->symbol_name && !p->addr))
1267		goto invalid;
1268
1269	if (p->symbol_name) {
1270		kprobe_lookup_name(p->symbol_name, addr);
1271		if (!addr)
1272			return ERR_PTR(-ENOENT);
1273	}
1274
1275	addr = (kprobe_opcode_t *)(((char *)addr) + p->offset);
1276	if (addr)
1277		return addr;
1278
1279invalid:
1280	return ERR_PTR(-EINVAL);
1281}
1282
 
 
 
 
 
1283/* Check passed kprobe is valid and return kprobe in kprobe_table. */
1284static struct kprobe * __kprobes __get_valid_kprobe(struct kprobe *p)
1285{
1286	struct kprobe *ap, *list_p;
1287
 
 
1288	ap = get_kprobe(p->addr);
1289	if (unlikely(!ap))
1290		return NULL;
1291
1292	if (p != ap) {
1293		list_for_each_entry_rcu(list_p, &ap->list, list)
1294			if (list_p == p)
1295			/* kprobe p is a valid probe */
1296				goto valid;
1297		return NULL;
1298	}
1299valid:
1300	return ap;
1301}
1302
1303/* Return error if the kprobe is being re-registered */
1304static inline int check_kprobe_rereg(struct kprobe *p)
 
 
 
1305{
1306	int ret = 0;
1307
1308	mutex_lock(&kprobe_mutex);
1309	if (__get_valid_kprobe(p))
1310		ret = -EINVAL;
1311	mutex_unlock(&kprobe_mutex);
1312
1313	return ret;
1314}
1315
1316int __kprobes register_kprobe(struct kprobe *p)
1317{
1318	int ret = 0;
1319	struct kprobe *old_p;
1320	struct module *probed_mod;
1321	kprobe_opcode_t *addr;
1322
1323	addr = kprobe_addr(p);
1324	if (IS_ERR(addr))
1325		return PTR_ERR(addr);
1326	p->addr = addr;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1327
1328	ret = check_kprobe_rereg(p);
1329	if (ret)
1330		return ret;
1331
1332	jump_label_lock();
1333	preempt_disable();
 
 
1334	if (!kernel_text_address((unsigned long) p->addr) ||
1335	    in_kprobes_functions((unsigned long) p->addr) ||
1336	    ftrace_text_reserved(p->addr, p->addr) ||
1337	    jump_label_text_reserved(p->addr, p->addr)) {
 
1338		ret = -EINVAL;
1339		goto cannot_probe;
1340	}
1341
1342	/* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
1343	p->flags &= KPROBE_FLAG_DISABLED;
1344
1345	/*
1346	 * Check if are we probing a module.
1347	 */
1348	probed_mod = __module_text_address((unsigned long) p->addr);
1349	if (probed_mod) {
1350		/* Return -ENOENT if fail. */
1351		ret = -ENOENT;
1352		/*
1353		 * We must hold a refcount of the probed module while updating
1354		 * its code to prohibit unexpected unloading.
1355		 */
1356		if (unlikely(!try_module_get(probed_mod)))
1357			goto cannot_probe;
 
 
1358
1359		/*
1360		 * If the module freed .init.text, we couldn't insert
1361		 * kprobes in there.
1362		 */
1363		if (within_module_init((unsigned long)p->addr, probed_mod) &&
1364		    probed_mod->state != MODULE_STATE_COMING) {
1365			module_put(probed_mod);
1366			goto cannot_probe;
 
1367		}
1368		/* ret will be updated by following code */
1369	}
 
1370	preempt_enable();
1371	jump_label_unlock();
1372
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1373	p->nmissed = 0;
1374	INIT_LIST_HEAD(&p->list);
1375	mutex_lock(&kprobe_mutex);
1376
1377	jump_label_lock(); /* needed to call jump_label_text_reserved() */
 
 
1378
1379	get_online_cpus();	/* For avoiding text_mutex deadlock. */
1380	mutex_lock(&text_mutex);
1381
1382	old_p = get_kprobe(p->addr);
1383	if (old_p) {
1384		/* Since this may unoptimize old_p, locking text_mutex. */
1385		ret = register_aggr_kprobe(old_p, p);
1386		goto out;
1387	}
1388
1389	ret = arch_prepare_kprobe(p);
 
 
 
 
 
1390	if (ret)
1391		goto out;
1392
1393	INIT_HLIST_NODE(&p->hlist);
1394	hlist_add_head_rcu(&p->hlist,
1395		       &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]);
1396
1397	if (!kprobes_all_disarmed && !kprobe_disabled(p))
1398		__arm_kprobe(p);
 
 
 
 
 
 
1399
1400	/* Try to optimize kprobe */
1401	try_to_optimize_kprobe(p);
1402
1403out:
1404	mutex_unlock(&text_mutex);
1405	put_online_cpus();
1406	jump_label_unlock();
1407	mutex_unlock(&kprobe_mutex);
1408
1409	if (probed_mod)
1410		module_put(probed_mod);
1411
1412	return ret;
1413
1414cannot_probe:
1415	preempt_enable();
1416	jump_label_unlock();
1417	return ret;
1418}
1419EXPORT_SYMBOL_GPL(register_kprobe);
1420
1421/* Check if all probes on the aggrprobe are disabled */
1422static int __kprobes aggr_kprobe_disabled(struct kprobe *ap)
1423{
1424	struct kprobe *kp;
1425
1426	list_for_each_entry_rcu(kp, &ap->list, list)
 
 
1427		if (!kprobe_disabled(kp))
1428			/*
1429			 * There is an active probe on the list.
1430			 * We can't disable this ap.
1431			 */
1432			return 0;
1433
1434	return 1;
1435}
1436
1437/* Disable one kprobe: Make sure called under kprobe_mutex is locked */
1438static struct kprobe *__kprobes __disable_kprobe(struct kprobe *p)
1439{
1440	struct kprobe *orig_p;
 
1441
1442	/* Get an original kprobe for return */
1443	orig_p = __get_valid_kprobe(p);
1444	if (unlikely(orig_p == NULL))
1445		return NULL;
1446
1447	if (!kprobe_disabled(p)) {
1448		/* Disable probe if it is a child probe */
1449		if (p != orig_p)
1450			p->flags |= KPROBE_FLAG_DISABLED;
1451
1452		/* Try to disarm and disable this/parent probe */
1453		if (p == orig_p || aggr_kprobe_disabled(orig_p)) {
1454			disarm_kprobe(orig_p);
 
 
 
 
 
 
 
 
 
 
 
1455			orig_p->flags |= KPROBE_FLAG_DISABLED;
1456		}
1457	}
1458
1459	return orig_p;
1460}
1461
1462/*
1463 * Unregister a kprobe without a scheduler synchronization.
1464 */
1465static int __kprobes __unregister_kprobe_top(struct kprobe *p)
1466{
1467	struct kprobe *ap, *list_p;
1468
1469	/* Disable kprobe. This will disarm it if needed. */
1470	ap = __disable_kprobe(p);
1471	if (ap == NULL)
1472		return -EINVAL;
1473
1474	if (ap == p)
1475		/*
1476		 * This probe is an independent(and non-optimized) kprobe
1477		 * (not an aggrprobe). Remove from the hash list.
1478		 */
1479		goto disarmed;
1480
1481	/* Following process expects this probe is an aggrprobe */
1482	WARN_ON(!kprobe_aggrprobe(ap));
1483
1484	if (list_is_singular(&ap->list) && kprobe_disarmed(ap))
1485		/*
1486		 * !disarmed could be happen if the probe is under delayed
1487		 * unoptimizing.
1488		 */
1489		goto disarmed;
1490	else {
1491		/* If disabling probe has special handlers, update aggrprobe */
1492		if (p->break_handler && !kprobe_gone(p))
1493			ap->break_handler = NULL;
1494		if (p->post_handler && !kprobe_gone(p)) {
1495			list_for_each_entry_rcu(list_p, &ap->list, list) {
1496				if ((list_p != p) && (list_p->post_handler))
1497					goto noclean;
1498			}
1499			ap->post_handler = NULL;
1500		}
1501noclean:
1502		/*
1503		 * Remove from the aggrprobe: this path will do nothing in
1504		 * __unregister_kprobe_bottom().
1505		 */
1506		list_del_rcu(&p->list);
1507		if (!kprobe_disabled(ap) && !kprobes_all_disarmed)
1508			/*
1509			 * Try to optimize this probe again, because post
1510			 * handler may have been changed.
1511			 */
1512			optimize_kprobe(ap);
1513	}
1514	return 0;
1515
1516disarmed:
1517	BUG_ON(!kprobe_disarmed(ap));
1518	hlist_del_rcu(&ap->hlist);
1519	return 0;
1520}
1521
1522static void __kprobes __unregister_kprobe_bottom(struct kprobe *p)
1523{
1524	struct kprobe *ap;
1525
1526	if (list_empty(&p->list))
1527		/* This is an independent kprobe */
1528		arch_remove_kprobe(p);
1529	else if (list_is_singular(&p->list)) {
1530		/* This is the last child of an aggrprobe */
1531		ap = list_entry(p->list.next, struct kprobe, list);
1532		list_del(&p->list);
1533		free_aggr_kprobe(ap);
1534	}
1535	/* Otherwise, do nothing. */
1536}
1537
1538int __kprobes register_kprobes(struct kprobe **kps, int num)
1539{
1540	int i, ret = 0;
1541
1542	if (num <= 0)
1543		return -EINVAL;
1544	for (i = 0; i < num; i++) {
1545		ret = register_kprobe(kps[i]);
1546		if (ret < 0) {
1547			if (i > 0)
1548				unregister_kprobes(kps, i);
1549			break;
1550		}
1551	}
1552	return ret;
1553}
1554EXPORT_SYMBOL_GPL(register_kprobes);
1555
1556void __kprobes unregister_kprobe(struct kprobe *p)
1557{
1558	unregister_kprobes(&p, 1);
1559}
1560EXPORT_SYMBOL_GPL(unregister_kprobe);
1561
1562void __kprobes unregister_kprobes(struct kprobe **kps, int num)
1563{
1564	int i;
1565
1566	if (num <= 0)
1567		return;
1568	mutex_lock(&kprobe_mutex);
1569	for (i = 0; i < num; i++)
1570		if (__unregister_kprobe_top(kps[i]) < 0)
1571			kps[i]->addr = NULL;
1572	mutex_unlock(&kprobe_mutex);
1573
1574	synchronize_sched();
1575	for (i = 0; i < num; i++)
1576		if (kps[i]->addr)
1577			__unregister_kprobe_bottom(kps[i]);
1578}
1579EXPORT_SYMBOL_GPL(unregister_kprobes);
1580
 
 
 
 
 
 
 
1581static struct notifier_block kprobe_exceptions_nb = {
1582	.notifier_call = kprobe_exceptions_notify,
1583	.priority = 0x7fffffff /* we need to be notified first */
1584};
1585
1586unsigned long __weak arch_deref_entry_point(void *entry)
1587{
1588	return (unsigned long)entry;
1589}
1590
1591int __kprobes register_jprobes(struct jprobe **jps, int num)
1592{
1593	struct jprobe *jp;
1594	int ret = 0, i;
1595
1596	if (num <= 0)
1597		return -EINVAL;
1598	for (i = 0; i < num; i++) {
1599		unsigned long addr, offset;
1600		jp = jps[i];
1601		addr = arch_deref_entry_point(jp->entry);
1602
1603		/* Verify probepoint is a function entry point */
1604		if (kallsyms_lookup_size_offset(addr, NULL, &offset) &&
1605		    offset == 0) {
1606			jp->kp.pre_handler = setjmp_pre_handler;
1607			jp->kp.break_handler = longjmp_break_handler;
1608			ret = register_kprobe(&jp->kp);
1609		} else
1610			ret = -EINVAL;
1611
1612		if (ret < 0) {
1613			if (i > 0)
1614				unregister_jprobes(jps, i);
1615			break;
 
 
 
 
 
 
1616		}
 
 
1617	}
1618	return ret;
1619}
1620EXPORT_SYMBOL_GPL(register_jprobes);
1621
1622int __kprobes register_jprobe(struct jprobe *jp)
1623{
1624	return register_jprobes(&jp, 1);
1625}
1626EXPORT_SYMBOL_GPL(register_jprobe);
1627
1628void __kprobes unregister_jprobe(struct jprobe *jp)
1629{
1630	unregister_jprobes(&jp, 1);
1631}
1632EXPORT_SYMBOL_GPL(unregister_jprobe);
1633
1634void __kprobes unregister_jprobes(struct jprobe **jps, int num)
1635{
1636	int i;
1637
1638	if (num <= 0)
1639		return;
1640	mutex_lock(&kprobe_mutex);
1641	for (i = 0; i < num; i++)
1642		if (__unregister_kprobe_top(&jps[i]->kp) < 0)
1643			jps[i]->kp.addr = NULL;
1644	mutex_unlock(&kprobe_mutex);
1645
1646	synchronize_sched();
1647	for (i = 0; i < num; i++) {
1648		if (jps[i]->kp.addr)
1649			__unregister_kprobe_bottom(&jps[i]->kp);
1650	}
 
 
1651}
1652EXPORT_SYMBOL_GPL(unregister_jprobes);
1653
1654#ifdef CONFIG_KRETPROBES
1655/*
1656 * This kprobe pre_handler is registered with every kretprobe. When probe
1657 * hits it will set up the return probe.
1658 */
1659static int __kprobes pre_handler_kretprobe(struct kprobe *p,
1660					   struct pt_regs *regs)
1661{
1662	struct kretprobe *rp = container_of(p, struct kretprobe, kp);
1663	unsigned long hash, flags = 0;
1664	struct kretprobe_instance *ri;
 
1665
1666	/*TODO: consider to only swap the RA after the last pre_handler fired */
1667	hash = hash_ptr(current, KPROBE_HASH_BITS);
1668	raw_spin_lock_irqsave(&rp->lock, flags);
1669	if (!hlist_empty(&rp->free_instances)) {
1670		ri = hlist_entry(rp->free_instances.first,
1671				struct kretprobe_instance, hlist);
1672		hlist_del(&ri->hlist);
1673		raw_spin_unlock_irqrestore(&rp->lock, flags);
1674
1675		ri->rp = rp;
1676		ri->task = current;
1677
1678		if (rp->entry_handler && rp->entry_handler(ri, regs)) {
1679			raw_spin_lock_irqsave(&rp->lock, flags);
1680			hlist_add_head(&ri->hlist, &rp->free_instances);
1681			raw_spin_unlock_irqrestore(&rp->lock, flags);
1682			return 0;
1683		}
1684
1685		arch_prepare_kretprobe(ri, regs);
1686
1687		/* XXX(hch): why is there no hlist_move_head? */
1688		INIT_HLIST_NODE(&ri->hlist);
1689		kretprobe_table_lock(hash, &flags);
1690		hlist_add_head(&ri->hlist, &kretprobe_inst_table[hash]);
1691		kretprobe_table_unlock(hash, &flags);
1692	} else {
1693		rp->nmissed++;
1694		raw_spin_unlock_irqrestore(&rp->lock, flags);
1695	}
 
 
 
 
 
1696	return 0;
1697}
 
1698
1699int __kprobes register_kretprobe(struct kretprobe *rp)
1700{
1701	int ret = 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1702	struct kretprobe_instance *inst;
1703	int i;
1704	void *addr;
1705
 
 
 
 
 
 
 
 
1706	if (kretprobe_blacklist_size) {
1707		addr = kprobe_addr(&rp->kp);
1708		if (IS_ERR(addr))
1709			return PTR_ERR(addr);
1710
1711		for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1712			if (kretprobe_blacklist[i].addr == addr)
1713				return -EINVAL;
1714		}
1715	}
1716
1717	rp->kp.pre_handler = pre_handler_kretprobe;
1718	rp->kp.post_handler = NULL;
1719	rp->kp.fault_handler = NULL;
1720	rp->kp.break_handler = NULL;
1721
1722	/* Pre-allocate memory for max kretprobe instances */
1723	if (rp->maxactive <= 0) {
1724#ifdef CONFIG_PREEMPT
1725		rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
1726#else
1727		rp->maxactive = num_possible_cpus();
1728#endif
1729	}
1730	raw_spin_lock_init(&rp->lock);
1731	INIT_HLIST_HEAD(&rp->free_instances);
 
 
 
 
1732	for (i = 0; i < rp->maxactive; i++) {
1733		inst = kmalloc(sizeof(struct kretprobe_instance) +
1734			       rp->data_size, GFP_KERNEL);
1735		if (inst == NULL) {
 
1736			free_rp_inst(rp);
1737			return -ENOMEM;
1738		}
1739		INIT_HLIST_NODE(&inst->hlist);
1740		hlist_add_head(&inst->hlist, &rp->free_instances);
1741	}
 
1742
1743	rp->nmissed = 0;
1744	/* Establish function entry probe point */
1745	ret = register_kprobe(&rp->kp);
1746	if (ret != 0)
1747		free_rp_inst(rp);
1748	return ret;
1749}
1750EXPORT_SYMBOL_GPL(register_kretprobe);
1751
1752int __kprobes register_kretprobes(struct kretprobe **rps, int num)
1753{
1754	int ret = 0, i;
1755
1756	if (num <= 0)
1757		return -EINVAL;
1758	for (i = 0; i < num; i++) {
1759		ret = register_kretprobe(rps[i]);
1760		if (ret < 0) {
1761			if (i > 0)
1762				unregister_kretprobes(rps, i);
1763			break;
1764		}
1765	}
1766	return ret;
1767}
1768EXPORT_SYMBOL_GPL(register_kretprobes);
1769
1770void __kprobes unregister_kretprobe(struct kretprobe *rp)
1771{
1772	unregister_kretprobes(&rp, 1);
1773}
1774EXPORT_SYMBOL_GPL(unregister_kretprobe);
1775
1776void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
1777{
1778	int i;
1779
1780	if (num <= 0)
1781		return;
1782	mutex_lock(&kprobe_mutex);
1783	for (i = 0; i < num; i++)
1784		if (__unregister_kprobe_top(&rps[i]->kp) < 0)
1785			rps[i]->kp.addr = NULL;
 
 
1786	mutex_unlock(&kprobe_mutex);
1787
1788	synchronize_sched();
1789	for (i = 0; i < num; i++) {
1790		if (rps[i]->kp.addr) {
1791			__unregister_kprobe_bottom(&rps[i]->kp);
1792			cleanup_rp_inst(rps[i]);
1793		}
1794	}
1795}
1796EXPORT_SYMBOL_GPL(unregister_kretprobes);
1797
1798#else /* CONFIG_KRETPROBES */
1799int __kprobes register_kretprobe(struct kretprobe *rp)
1800{
1801	return -ENOSYS;
1802}
1803EXPORT_SYMBOL_GPL(register_kretprobe);
1804
1805int __kprobes register_kretprobes(struct kretprobe **rps, int num)
1806{
1807	return -ENOSYS;
1808}
1809EXPORT_SYMBOL_GPL(register_kretprobes);
1810
1811void __kprobes unregister_kretprobe(struct kretprobe *rp)
1812{
1813}
1814EXPORT_SYMBOL_GPL(unregister_kretprobe);
1815
1816void __kprobes unregister_kretprobes(struct kretprobe **rps, int num)
1817{
1818}
1819EXPORT_SYMBOL_GPL(unregister_kretprobes);
1820
1821static int __kprobes pre_handler_kretprobe(struct kprobe *p,
1822					   struct pt_regs *regs)
1823{
1824	return 0;
1825}
 
1826
1827#endif /* CONFIG_KRETPROBES */
1828
1829/* Set the kprobe gone and remove its instruction buffer. */
1830static void __kprobes kill_kprobe(struct kprobe *p)
1831{
1832	struct kprobe *kp;
1833
 
 
1834	p->flags |= KPROBE_FLAG_GONE;
1835	if (kprobe_aggrprobe(p)) {
1836		/*
1837		 * If this is an aggr_kprobe, we have to list all the
1838		 * chained probes and mark them GONE.
1839		 */
1840		list_for_each_entry_rcu(kp, &p->list, list)
1841			kp->flags |= KPROBE_FLAG_GONE;
1842		p->post_handler = NULL;
1843		p->break_handler = NULL;
1844		kill_optimized_kprobe(p);
1845	}
1846	/*
1847	 * Here, we can remove insn_slot safely, because no thread calls
1848	 * the original probed function (which will be freed soon) any more.
1849	 */
1850	arch_remove_kprobe(p);
 
 
 
 
 
 
 
 
1851}
1852
1853/* Disable one kprobe */
1854int __kprobes disable_kprobe(struct kprobe *kp)
1855{
1856	int ret = 0;
 
1857
1858	mutex_lock(&kprobe_mutex);
1859
1860	/* Disable this kprobe */
1861	if (__disable_kprobe(kp) == NULL)
1862		ret = -EINVAL;
 
1863
1864	mutex_unlock(&kprobe_mutex);
1865	return ret;
1866}
1867EXPORT_SYMBOL_GPL(disable_kprobe);
1868
1869/* Enable one kprobe */
1870int __kprobes enable_kprobe(struct kprobe *kp)
1871{
1872	int ret = 0;
1873	struct kprobe *p;
1874
1875	mutex_lock(&kprobe_mutex);
1876
1877	/* Check whether specified probe is valid. */
1878	p = __get_valid_kprobe(kp);
1879	if (unlikely(p == NULL)) {
1880		ret = -EINVAL;
1881		goto out;
1882	}
1883
1884	if (kprobe_gone(kp)) {
1885		/* This kprobe has gone, we couldn't enable it. */
1886		ret = -EINVAL;
1887		goto out;
1888	}
1889
1890	if (p != kp)
1891		kp->flags &= ~KPROBE_FLAG_DISABLED;
1892
1893	if (!kprobes_all_disarmed && kprobe_disabled(p)) {
1894		p->flags &= ~KPROBE_FLAG_DISABLED;
1895		arm_kprobe(p);
 
 
1896	}
1897out:
1898	mutex_unlock(&kprobe_mutex);
1899	return ret;
1900}
1901EXPORT_SYMBOL_GPL(enable_kprobe);
1902
1903void __kprobes dump_kprobe(struct kprobe *kp)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1904{
1905	printk(KERN_WARNING "Dumping kprobe:\n");
1906	printk(KERN_WARNING "Name: %s\nAddress: %p\nOffset: %x\n",
1907	       kp->symbol_name, kp->addr, kp->offset);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1908}
1909
1910/* Module notifier call back, checking kprobes on the module */
1911static int __kprobes kprobes_module_callback(struct notifier_block *nb,
1912					     unsigned long val, void *data)
1913{
1914	struct module *mod = data;
1915	struct hlist_head *head;
1916	struct hlist_node *node;
1917	struct kprobe *p;
1918	unsigned int i;
1919	int checkcore = (val == MODULE_STATE_GOING);
1920
 
 
 
 
 
1921	if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
1922		return NOTIFY_DONE;
1923
1924	/*
1925	 * When MODULE_STATE_GOING was notified, both of module .text and
1926	 * .init.text sections would be freed. When MODULE_STATE_LIVE was
1927	 * notified, only .init.text section would be freed. We need to
1928	 * disable kprobes which have been inserted in the sections.
1929	 */
1930	mutex_lock(&kprobe_mutex);
1931	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1932		head = &kprobe_table[i];
1933		hlist_for_each_entry_rcu(p, node, head, hlist)
1934			if (within_module_init((unsigned long)p->addr, mod) ||
1935			    (checkcore &&
1936			     within_module_core((unsigned long)p->addr, mod))) {
1937				/*
1938				 * The vaddr this probe is installed will soon
1939				 * be vfreed buy not synced to disk. Hence,
1940				 * disarming the breakpoint isn't needed.
 
 
 
 
 
 
1941				 */
1942				kill_kprobe(p);
1943			}
1944	}
 
 
1945	mutex_unlock(&kprobe_mutex);
1946	return NOTIFY_DONE;
1947}
1948
1949static struct notifier_block kprobe_module_nb = {
1950	.notifier_call = kprobes_module_callback,
1951	.priority = 0
1952};
1953
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1954static int __init init_kprobes(void)
1955{
1956	int i, err = 0;
1957	unsigned long offset = 0, size = 0;
1958	char *modname, namebuf[128];
1959	const char *symbol_name;
1960	void *addr;
1961	struct kprobe_blackpoint *kb;
1962
1963	/* FIXME allocate the probe table, currently defined statically */
1964	/* initialize all list heads */
1965	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
1966		INIT_HLIST_HEAD(&kprobe_table[i]);
1967		INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
1968		raw_spin_lock_init(&(kretprobe_table_locks[i].lock));
1969	}
1970
1971	/*
1972	 * Lookup and populate the kprobe_blacklist.
1973	 *
1974	 * Unlike the kretprobe blacklist, we'll need to determine
1975	 * the range of addresses that belong to the said functions,
1976	 * since a kprobe need not necessarily be at the beginning
1977	 * of a function.
1978	 */
1979	for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
1980		kprobe_lookup_name(kb->name, addr);
1981		if (!addr)
1982			continue;
1983
1984		kb->start_addr = (unsigned long)addr;
1985		symbol_name = kallsyms_lookup(kb->start_addr,
1986				&size, &offset, &modname, namebuf);
1987		if (!symbol_name)
1988			kb->range = 0;
1989		else
1990			kb->range = size;
1991	}
1992
1993	if (kretprobe_blacklist_size) {
1994		/* lookup the function address from its name */
1995		for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
1996			kprobe_lookup_name(kretprobe_blacklist[i].name,
1997					   kretprobe_blacklist[i].addr);
1998			if (!kretprobe_blacklist[i].addr)
1999				printk("kretprobe: lookup failed: %s\n",
2000				       kretprobe_blacklist[i].name);
2001		}
2002	}
2003
2004#if defined(CONFIG_OPTPROBES)
2005#if defined(__ARCH_WANT_KPROBES_INSN_SLOT)
2006	/* Init kprobe_optinsn_slots */
2007	kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
2008#endif
2009	/* By default, kprobes can be optimized */
2010	kprobes_allow_optimization = true;
2011#endif
2012
2013	/* By default, kprobes are armed */
2014	kprobes_all_disarmed = false;
2015
 
 
 
 
 
2016	err = arch_init_kprobes();
2017	if (!err)
2018		err = register_die_notifier(&kprobe_exceptions_nb);
2019	if (!err)
2020		err = register_module_notifier(&kprobe_module_nb);
2021
2022	kprobes_initialized = (err == 0);
2023
2024	if (!err)
2025		init_test_probes();
2026	return err;
2027}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2028
2029#ifdef CONFIG_DEBUG_FS
2030static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p,
2031		const char *sym, int offset, char *modname, struct kprobe *pp)
2032{
2033	char *kprobe_type;
 
2034
2035	if (p->pre_handler == pre_handler_kretprobe)
2036		kprobe_type = "r";
2037	else if (p->pre_handler == setjmp_pre_handler)
2038		kprobe_type = "j";
2039	else
2040		kprobe_type = "k";
2041
 
 
 
2042	if (sym)
2043		seq_printf(pi, "%p  %s  %s+0x%x  %s ",
2044			p->addr, kprobe_type, sym, offset,
2045			(modname ? modname : " "));
2046	else
2047		seq_printf(pi, "%p  %s  %p ",
2048			p->addr, kprobe_type, p->addr);
2049
2050	if (!pp)
2051		pp = p;
2052	seq_printf(pi, "%s%s%s\n",
2053		(kprobe_gone(p) ? "[GONE]" : ""),
2054		((kprobe_disabled(p) && !kprobe_gone(p)) ?  "[DISABLED]" : ""),
2055		(kprobe_optimized(pp) ? "[OPTIMIZED]" : ""));
 
2056}
2057
2058static void __kprobes *kprobe_seq_start(struct seq_file *f, loff_t *pos)
2059{
2060	return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
2061}
2062
2063static void __kprobes *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
2064{
2065	(*pos)++;
2066	if (*pos >= KPROBE_TABLE_SIZE)
2067		return NULL;
2068	return pos;
2069}
2070
2071static void __kprobes kprobe_seq_stop(struct seq_file *f, void *v)
2072{
2073	/* Nothing to do */
2074}
2075
2076static int __kprobes show_kprobe_addr(struct seq_file *pi, void *v)
2077{
2078	struct hlist_head *head;
2079	struct hlist_node *node;
2080	struct kprobe *p, *kp;
2081	const char *sym = NULL;
2082	unsigned int i = *(loff_t *) v;
2083	unsigned long offset = 0;
2084	char *modname, namebuf[128];
2085
2086	head = &kprobe_table[i];
2087	preempt_disable();
2088	hlist_for_each_entry_rcu(p, node, head, hlist) {
2089		sym = kallsyms_lookup((unsigned long)p->addr, NULL,
2090					&offset, &modname, namebuf);
2091		if (kprobe_aggrprobe(p)) {
2092			list_for_each_entry_rcu(kp, &p->list, list)
2093				report_probe(pi, kp, sym, offset, modname, p);
2094		} else
2095			report_probe(pi, p, sym, offset, modname, NULL);
2096	}
2097	preempt_enable();
2098	return 0;
2099}
2100
2101static const struct seq_operations kprobes_seq_ops = {
2102	.start = kprobe_seq_start,
2103	.next  = kprobe_seq_next,
2104	.stop  = kprobe_seq_stop,
2105	.show  = show_kprobe_addr
2106};
2107
2108static int __kprobes kprobes_open(struct inode *inode, struct file *filp)
 
 
 
 
 
 
 
 
 
2109{
2110	return seq_open(filp, &kprobes_seq_ops);
2111}
2112
2113static const struct file_operations debugfs_kprobes_operations = {
2114	.open           = kprobes_open,
2115	.read           = seq_read,
2116	.llseek         = seq_lseek,
2117	.release        = seq_release,
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2118};
 
2119
2120static void __kprobes arm_all_kprobes(void)
2121{
2122	struct hlist_head *head;
2123	struct hlist_node *node;
2124	struct kprobe *p;
2125	unsigned int i;
 
2126
2127	mutex_lock(&kprobe_mutex);
2128
2129	/* If kprobes are armed, just return */
2130	if (!kprobes_all_disarmed)
2131		goto already_enabled;
2132
 
 
 
 
 
 
2133	/* Arming kprobes doesn't optimize kprobe itself */
2134	mutex_lock(&text_mutex);
2135	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2136		head = &kprobe_table[i];
2137		hlist_for_each_entry_rcu(p, node, head, hlist)
2138			if (!kprobe_disabled(p))
2139				__arm_kprobe(p);
 
 
 
 
 
 
 
 
2140	}
2141	mutex_unlock(&text_mutex);
2142
2143	kprobes_all_disarmed = false;
2144	printk(KERN_INFO "Kprobes globally enabled\n");
 
 
 
2145
2146already_enabled:
2147	mutex_unlock(&kprobe_mutex);
2148	return;
2149}
2150
2151static void __kprobes disarm_all_kprobes(void)
2152{
2153	struct hlist_head *head;
2154	struct hlist_node *node;
2155	struct kprobe *p;
2156	unsigned int i;
 
2157
2158	mutex_lock(&kprobe_mutex);
2159
2160	/* If kprobes are already disarmed, just return */
2161	if (kprobes_all_disarmed) {
2162		mutex_unlock(&kprobe_mutex);
2163		return;
2164	}
2165
2166	kprobes_all_disarmed = true;
2167	printk(KERN_INFO "Kprobes globally disabled\n");
2168
2169	mutex_lock(&text_mutex);
2170	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2171		head = &kprobe_table[i];
2172		hlist_for_each_entry_rcu(p, node, head, hlist) {
2173			if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p))
2174				__disarm_kprobe(p, false);
 
 
 
 
 
 
 
2175		}
2176	}
2177	mutex_unlock(&text_mutex);
 
 
 
 
 
 
2178	mutex_unlock(&kprobe_mutex);
2179
2180	/* Wait for disarming all kprobes by optimizer */
2181	wait_for_kprobe_optimizer();
 
 
2182}
2183
2184/*
2185 * XXX: The debugfs bool file interface doesn't allow for callbacks
2186 * when the bool state is switched. We can reuse that facility when
2187 * available
2188 */
2189static ssize_t read_enabled_file_bool(struct file *file,
2190	       char __user *user_buf, size_t count, loff_t *ppos)
2191{
2192	char buf[3];
2193
2194	if (!kprobes_all_disarmed)
2195		buf[0] = '1';
2196	else
2197		buf[0] = '0';
2198	buf[1] = '\n';
2199	buf[2] = 0x00;
2200	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
2201}
2202
2203static ssize_t write_enabled_file_bool(struct file *file,
2204	       const char __user *user_buf, size_t count, loff_t *ppos)
2205{
2206	char buf[32];
2207	size_t buf_size;
 
2208
2209	buf_size = min(count, (sizeof(buf)-1));
2210	if (copy_from_user(buf, user_buf, buf_size))
2211		return -EFAULT;
2212
 
2213	switch (buf[0]) {
2214	case 'y':
2215	case 'Y':
2216	case '1':
2217		arm_all_kprobes();
2218		break;
2219	case 'n':
2220	case 'N':
2221	case '0':
2222		disarm_all_kprobes();
2223		break;
 
 
2224	}
2225
 
 
 
2226	return count;
2227}
2228
2229static const struct file_operations fops_kp = {
2230	.read =         read_enabled_file_bool,
2231	.write =        write_enabled_file_bool,
2232	.llseek =	default_llseek,
2233};
2234
2235static int __kprobes debugfs_kprobe_init(void)
2236{
2237	struct dentry *dir, *file;
2238	unsigned int value = 1;
2239
2240	dir = debugfs_create_dir("kprobes", NULL);
2241	if (!dir)
2242		return -ENOMEM;
2243
2244	file = debugfs_create_file("list", 0444, dir, NULL,
2245				&debugfs_kprobes_operations);
2246	if (!file) {
2247		debugfs_remove(dir);
2248		return -ENOMEM;
2249	}
2250
2251	file = debugfs_create_file("enabled", 0600, dir,
2252					&value, &fops_kp);
2253	if (!file) {
2254		debugfs_remove(dir);
2255		return -ENOMEM;
2256	}
2257
2258	return 0;
2259}
2260
2261late_initcall(debugfs_kprobe_init);
2262#endif /* CONFIG_DEBUG_FS */
2263
2264module_init(init_kprobes);
2265
2266/* defined in arch/.../kernel/kprobes.c */
2267EXPORT_SYMBOL_GPL(jprobe_return);