1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Kernel Probes (KProbes)
4 *
5 * Copyright (C) IBM Corporation, 2002, 2004
6 *
7 * 2002-Oct Created by Vamsi Krishna S <vamsi_krishna@in.ibm.com> Kernel
8 * Probes initial implementation (includes suggestions from
9 * Rusty Russell).
10 * 2004-Aug Updated by Prasanna S Panchamukhi <prasanna@in.ibm.com> with
11 * hlists and exceptions notifier as suggested by Andi Kleen.
12 * 2004-July Suparna Bhattacharya <suparna@in.ibm.com> added jumper probes
13 * interface to access function arguments.
14 * 2004-Sep Prasanna S Panchamukhi <prasanna@in.ibm.com> Changed Kprobes
15 * exceptions notifier to be first on the priority list.
16 * 2005-May Hien Nguyen <hien@us.ibm.com>, Jim Keniston
17 * <jkenisto@us.ibm.com> and Prasanna S Panchamukhi
18 * <prasanna@in.ibm.com> added function-return probes.
19 */
20
21#define pr_fmt(fmt) "kprobes: " fmt
22
23#include <linux/kprobes.h>
24#include <linux/hash.h>
25#include <linux/init.h>
26#include <linux/slab.h>
27#include <linux/stddef.h>
28#include <linux/export.h>
29#include <linux/moduleloader.h>
30#include <linux/kallsyms.h>
31#include <linux/freezer.h>
32#include <linux/seq_file.h>
33#include <linux/debugfs.h>
34#include <linux/sysctl.h>
35#include <linux/kdebug.h>
36#include <linux/memory.h>
37#include <linux/ftrace.h>
38#include <linux/cpu.h>
39#include <linux/jump_label.h>
40#include <linux/static_call.h>
41#include <linux/perf_event.h>
42
43#include <asm/sections.h>
44#include <asm/cacheflush.h>
45#include <asm/errno.h>
46#include <linux/uaccess.h>
47
48#define KPROBE_HASH_BITS 6
49#define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS)
50
51#if !defined(CONFIG_OPTPROBES) || !defined(CONFIG_SYSCTL)
52#define kprobe_sysctls_init() do { } while (0)
53#endif
54
55static int kprobes_initialized;
56/* kprobe_table can be accessed by
57 * - Normal hlist traversal and RCU add/del under 'kprobe_mutex' is held.
58 * Or
59 * - RCU hlist traversal under disabling preempt (breakpoint handlers)
60 */
61static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
62
63/* NOTE: change this value only with 'kprobe_mutex' held */
64static bool kprobes_all_disarmed;
65
66/* This protects 'kprobe_table' and 'optimizing_list' */
67static DEFINE_MUTEX(kprobe_mutex);
68static DEFINE_PER_CPU(struct kprobe *, kprobe_instance);
69
70kprobe_opcode_t * __weak kprobe_lookup_name(const char *name,
71 unsigned int __unused)
72{
73 return ((kprobe_opcode_t *)(kallsyms_lookup_name(name)));
74}
75
76/*
77 * Blacklist -- list of 'struct kprobe_blacklist_entry' to store info where
78 * kprobes can not probe.
79 */
80static LIST_HEAD(kprobe_blacklist);
81
82#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
83/*
84 * 'kprobe::ainsn.insn' points to the copy of the instruction to be
85 * single-stepped. x86_64, POWER4 and above have no-exec support and
86 * stepping on the instruction on a vmalloced/kmalloced/data page
87 * is a recipe for disaster
88 */
89struct kprobe_insn_page {
90 struct list_head list;
91 kprobe_opcode_t *insns; /* Page of instruction slots */
92 struct kprobe_insn_cache *cache;
93 int nused;
94 int ngarbage;
95 char slot_used[];
96};
97
98#define KPROBE_INSN_PAGE_SIZE(slots) \
99 (offsetof(struct kprobe_insn_page, slot_used) + \
100 (sizeof(char) * (slots)))
101
102static int slots_per_page(struct kprobe_insn_cache *c)
103{
104 return PAGE_SIZE/(c->insn_size * sizeof(kprobe_opcode_t));
105}
106
107enum kprobe_slot_state {
108 SLOT_CLEAN = 0,
109 SLOT_DIRTY = 1,
110 SLOT_USED = 2,
111};
112
113void __weak *alloc_insn_page(void)
114{
115 /*
116 * Use module_alloc() so this page is within +/- 2GB of where the
117 * kernel image and loaded module images reside. This is required
118 * for most of the architectures.
119 * (e.g. x86-64 needs this to handle the %rip-relative fixups.)
120 */
121 return module_alloc(PAGE_SIZE);
122}
123
124static void free_insn_page(void *page)
125{
126 module_memfree(module_region: page);
127}
128
129struct kprobe_insn_cache kprobe_insn_slots = {
130 .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex),
131 .alloc = alloc_insn_page,
132 .free = free_insn_page,
133 .sym = KPROBE_INSN_PAGE_SYM,
134 .pages = LIST_HEAD_INIT(kprobe_insn_slots.pages),
135 .insn_size = MAX_INSN_SIZE,
136 .nr_garbage = 0,
137};
138static int collect_garbage_slots(struct kprobe_insn_cache *c);
139
140/**
141 * __get_insn_slot() - Find a slot on an executable page for an instruction.
142 * We allocate an executable page if there's no room on existing ones.
143 */
144kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c)
145{
146 struct kprobe_insn_page *kip;
147 kprobe_opcode_t *slot = NULL;
148
149 /* Since the slot array is not protected by rcu, we need a mutex */
150 mutex_lock(&c->mutex);
151 retry:
152 rcu_read_lock();
153 list_for_each_entry_rcu(kip, &c->pages, list) {
154 if (kip->nused < slots_per_page(c)) {
155 int i;
156
157 for (i = 0; i < slots_per_page(c); i++) {
158 if (kip->slot_used[i] == SLOT_CLEAN) {
159 kip->slot_used[i] = SLOT_USED;
160 kip->nused++;
161 slot = kip->insns + (i * c->insn_size);
162 rcu_read_unlock();
163 goto out;
164 }
165 }
166 /* kip->nused is broken. Fix it. */
167 kip->nused = slots_per_page(c);
168 WARN_ON(1);
169 }
170 }
171 rcu_read_unlock();
172
173 /* If there are any garbage slots, collect it and try again. */
174 if (c->nr_garbage && collect_garbage_slots(c) == 0)
175 goto retry;
176
177 /* All out of space. Need to allocate a new page. */
178 kip = kmalloc(KPROBE_INSN_PAGE_SIZE(slots_per_page(c)), GFP_KERNEL);
179 if (!kip)
180 goto out;
181
182 kip->insns = c->alloc();
183 if (!kip->insns) {
184 kfree(objp: kip);
185 goto out;
186 }
187 INIT_LIST_HEAD(list: &kip->list);
188 memset(kip->slot_used, SLOT_CLEAN, slots_per_page(c));
189 kip->slot_used[0] = SLOT_USED;
190 kip->nused = 1;
191 kip->ngarbage = 0;
192 kip->cache = c;
193 list_add_rcu(new: &kip->list, head: &c->pages);
194 slot = kip->insns;
195
196 /* Record the perf ksymbol register event after adding the page */
197 perf_event_ksymbol(ksym_type: PERF_RECORD_KSYMBOL_TYPE_OOL, addr: (unsigned long)kip->insns,
198 PAGE_SIZE, unregister: false, sym: c->sym);
199out:
200 mutex_unlock(lock: &c->mutex);
201 return slot;
202}
203
204/* Return true if all garbages are collected, otherwise false. */
205static bool collect_one_slot(struct kprobe_insn_page *kip, int idx)
206{
207 kip->slot_used[idx] = SLOT_CLEAN;
208 kip->nused--;
209 if (kip->nused == 0) {
210 /*
211 * Page is no longer in use. Free it unless
212 * it's the last one. We keep the last one
213 * so as not to have to set it up again the
214 * next time somebody inserts a probe.
215 */
216 if (!list_is_singular(head: &kip->list)) {
217 /*
218 * Record perf ksymbol unregister event before removing
219 * the page.
220 */
221 perf_event_ksymbol(ksym_type: PERF_RECORD_KSYMBOL_TYPE_OOL,
222 addr: (unsigned long)kip->insns, PAGE_SIZE, unregister: true,
223 sym: kip->cache->sym);
224 list_del_rcu(entry: &kip->list);
225 synchronize_rcu();
226 kip->cache->free(kip->insns);
227 kfree(objp: kip);
228 }
229 return true;
230 }
231 return false;
232}
233
234static int collect_garbage_slots(struct kprobe_insn_cache *c)
235{
236 struct kprobe_insn_page *kip, *next;
237
238 /* Ensure no-one is interrupted on the garbages */
239 synchronize_rcu();
240
241 list_for_each_entry_safe(kip, next, &c->pages, list) {
242 int i;
243
244 if (kip->ngarbage == 0)
245 continue;
246 kip->ngarbage = 0; /* we will collect all garbages */
247 for (i = 0; i < slots_per_page(c); i++) {
248 if (kip->slot_used[i] == SLOT_DIRTY && collect_one_slot(kip, idx: i))
249 break;
250 }
251 }
252 c->nr_garbage = 0;
253 return 0;
254}
255
256void __free_insn_slot(struct kprobe_insn_cache *c,
257 kprobe_opcode_t *slot, int dirty)
258{
259 struct kprobe_insn_page *kip;
260 long idx;
261
262 mutex_lock(&c->mutex);
263 rcu_read_lock();
264 list_for_each_entry_rcu(kip, &c->pages, list) {
265 idx = ((long)slot - (long)kip->insns) /
266 (c->insn_size * sizeof(kprobe_opcode_t));
267 if (idx >= 0 && idx < slots_per_page(c))
268 goto out;
269 }
270 /* Could not find this slot. */
271 WARN_ON(1);
272 kip = NULL;
273out:
274 rcu_read_unlock();
275 /* Mark and sweep: this may sleep */
276 if (kip) {
277 /* Check double free */
278 WARN_ON(kip->slot_used[idx] != SLOT_USED);
279 if (dirty) {
280 kip->slot_used[idx] = SLOT_DIRTY;
281 kip->ngarbage++;
282 if (++c->nr_garbage > slots_per_page(c))
283 collect_garbage_slots(c);
284 } else {
285 collect_one_slot(kip, idx);
286 }
287 }
288 mutex_unlock(lock: &c->mutex);
289}
290
291/*
292 * Check given address is on the page of kprobe instruction slots.
293 * This will be used for checking whether the address on a stack
294 * is on a text area or not.
295 */
296bool __is_insn_slot_addr(struct kprobe_insn_cache *c, unsigned long addr)
297{
298 struct kprobe_insn_page *kip;
299 bool ret = false;
300
301 rcu_read_lock();
302 list_for_each_entry_rcu(kip, &c->pages, list) {
303 if (addr >= (unsigned long)kip->insns &&
304 addr < (unsigned long)kip->insns + PAGE_SIZE) {
305 ret = true;
306 break;
307 }
308 }
309 rcu_read_unlock();
310
311 return ret;
312}
313
314int kprobe_cache_get_kallsym(struct kprobe_insn_cache *c, unsigned int *symnum,
315 unsigned long *value, char *type, char *sym)
316{
317 struct kprobe_insn_page *kip;
318 int ret = -ERANGE;
319
320 rcu_read_lock();
321 list_for_each_entry_rcu(kip, &c->pages, list) {
322 if ((*symnum)--)
323 continue;
324 strscpy(sym, c->sym, KSYM_NAME_LEN);
325 *type = 't';
326 *value = (unsigned long)kip->insns;
327 ret = 0;
328 break;
329 }
330 rcu_read_unlock();
331
332 return ret;
333}
334
335#ifdef CONFIG_OPTPROBES
336void __weak *alloc_optinsn_page(void)
337{
338 return alloc_insn_page();
339}
340
341void __weak free_optinsn_page(void *page)
342{
343 free_insn_page(page);
344}
345
346/* For optimized_kprobe buffer */
347struct kprobe_insn_cache kprobe_optinsn_slots = {
348 .mutex = __MUTEX_INITIALIZER(kprobe_optinsn_slots.mutex),
349 .alloc = alloc_optinsn_page,
350 .free = free_optinsn_page,
351 .sym = KPROBE_OPTINSN_PAGE_SYM,
352 .pages = LIST_HEAD_INIT(kprobe_optinsn_slots.pages),
353 /* .insn_size is initialized later */
354 .nr_garbage = 0,
355};
356#endif
357#endif
358
359/* We have preemption disabled.. so it is safe to use __ versions */
360static inline void set_kprobe_instance(struct kprobe *kp)
361{
362 __this_cpu_write(kprobe_instance, kp);
363}
364
365static inline void reset_kprobe_instance(void)
366{
367 __this_cpu_write(kprobe_instance, NULL);
368}
369
370/*
371 * This routine is called either:
372 * - under the 'kprobe_mutex' - during kprobe_[un]register().
373 * OR
374 * - with preemption disabled - from architecture specific code.
375 */
376struct kprobe *get_kprobe(void *addr)
377{
378 struct hlist_head *head;
379 struct kprobe *p;
380
381 head = &kprobe_table[hash_ptr(ptr: addr, KPROBE_HASH_BITS)];
382 hlist_for_each_entry_rcu(p, head, hlist,
383 lockdep_is_held(&kprobe_mutex)) {
384 if (p->addr == addr)
385 return p;
386 }
387
388 return NULL;
389}
390NOKPROBE_SYMBOL(get_kprobe);
391
392static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs);
393
394/* Return true if 'p' is an aggregator */
395static inline bool kprobe_aggrprobe(struct kprobe *p)
396{
397 return p->pre_handler == aggr_pre_handler;
398}
399
400/* Return true if 'p' is unused */
401static inline bool kprobe_unused(struct kprobe *p)
402{
403 return kprobe_aggrprobe(p) && kprobe_disabled(p) &&
404 list_empty(head: &p->list);
405}
406
407/* Keep all fields in the kprobe consistent. */
408static inline void copy_kprobe(struct kprobe *ap, struct kprobe *p)
409{
410 memcpy(&p->opcode, &ap->opcode, sizeof(kprobe_opcode_t));
411 memcpy(&p->ainsn, &ap->ainsn, sizeof(struct arch_specific_insn));
412}
413
414#ifdef CONFIG_OPTPROBES
415/* NOTE: This is protected by 'kprobe_mutex'. */
416static bool kprobes_allow_optimization;
417
418/*
419 * Call all 'kprobe::pre_handler' on the list, but ignores its return value.
420 * This must be called from arch-dep optimized caller.
421 */
422void opt_pre_handler(struct kprobe *p, struct pt_regs *regs)
423{
424 struct kprobe *kp;
425
426 list_for_each_entry_rcu(kp, &p->list, list) {
427 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
428 set_kprobe_instance(kp);
429 kp->pre_handler(kp, regs);
430 }
431 reset_kprobe_instance();
432 }
433}
434NOKPROBE_SYMBOL(opt_pre_handler);
435
436/* Free optimized instructions and optimized_kprobe */
437static void free_aggr_kprobe(struct kprobe *p)
438{
439 struct optimized_kprobe *op;
440
441 op = container_of(p, struct optimized_kprobe, kp);
442 arch_remove_optimized_kprobe(op);
443 arch_remove_kprobe(p);
444 kfree(objp: op);
445}
446
447/* Return true if the kprobe is ready for optimization. */
448static inline int kprobe_optready(struct kprobe *p)
449{
450 struct optimized_kprobe *op;
451
452 if (kprobe_aggrprobe(p)) {
453 op = container_of(p, struct optimized_kprobe, kp);
454 return arch_prepared_optinsn(optinsn: &op->optinsn);
455 }
456
457 return 0;
458}
459
460/* Return true if the kprobe is disarmed. Note: p must be on hash list */
461bool kprobe_disarmed(struct kprobe *p)
462{
463 struct optimized_kprobe *op;
464
465 /* If kprobe is not aggr/opt probe, just return kprobe is disabled */
466 if (!kprobe_aggrprobe(p))
467 return kprobe_disabled(p);
468
469 op = container_of(p, struct optimized_kprobe, kp);
470
471 return kprobe_disabled(p) && list_empty(head: &op->list);
472}
473
474/* Return true if the probe is queued on (un)optimizing lists */
475static bool kprobe_queued(struct kprobe *p)
476{
477 struct optimized_kprobe *op;
478
479 if (kprobe_aggrprobe(p)) {
480 op = container_of(p, struct optimized_kprobe, kp);
481 if (!list_empty(head: &op->list))
482 return true;
483 }
484 return false;
485}
486
487/*
488 * Return an optimized kprobe whose optimizing code replaces
489 * instructions including 'addr' (exclude breakpoint).
490 */
491static struct kprobe *get_optimized_kprobe(kprobe_opcode_t *addr)
492{
493 int i;
494 struct kprobe *p = NULL;
495 struct optimized_kprobe *op;
496
497 /* Don't check i == 0, since that is a breakpoint case. */
498 for (i = 1; !p && i < MAX_OPTIMIZED_LENGTH / sizeof(kprobe_opcode_t); i++)
499 p = get_kprobe(addr: addr - i);
500
501 if (p && kprobe_optready(p)) {
502 op = container_of(p, struct optimized_kprobe, kp);
503 if (arch_within_optimized_kprobe(op, addr))
504 return p;
505 }
506
507 return NULL;
508}
509
510/* Optimization staging list, protected by 'kprobe_mutex' */
511static LIST_HEAD(optimizing_list);
512static LIST_HEAD(unoptimizing_list);
513static LIST_HEAD(freeing_list);
514
515static void kprobe_optimizer(struct work_struct *work);
516static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
517#define OPTIMIZE_DELAY 5
518
519/*
520 * Optimize (replace a breakpoint with a jump) kprobes listed on
521 * 'optimizing_list'.
522 */
523static void do_optimize_kprobes(void)
524{
525 lockdep_assert_held(&text_mutex);
526 /*
527 * The optimization/unoptimization refers 'online_cpus' via
528 * stop_machine() and cpu-hotplug modifies the 'online_cpus'.
529 * And same time, 'text_mutex' will be held in cpu-hotplug and here.
530 * This combination can cause a deadlock (cpu-hotplug tries to lock
531 * 'text_mutex' but stop_machine() can not be done because
532 * the 'online_cpus' has been changed)
533 * To avoid this deadlock, caller must have locked cpu-hotplug
534 * for preventing cpu-hotplug outside of 'text_mutex' locking.
535 */
536 lockdep_assert_cpus_held();
537
538 /* Optimization never be done when disarmed */
539 if (kprobes_all_disarmed || !kprobes_allow_optimization ||
540 list_empty(head: &optimizing_list))
541 return;
542
543 arch_optimize_kprobes(oplist: &optimizing_list);
544}
545
546/*
547 * Unoptimize (replace a jump with a breakpoint and remove the breakpoint
548 * if need) kprobes listed on 'unoptimizing_list'.
549 */
550static void do_unoptimize_kprobes(void)
551{
552 struct optimized_kprobe *op, *tmp;
553
554 lockdep_assert_held(&text_mutex);
555 /* See comment in do_optimize_kprobes() */
556 lockdep_assert_cpus_held();
557
558 if (!list_empty(head: &unoptimizing_list))
559 arch_unoptimize_kprobes(oplist: &unoptimizing_list, done_list: &freeing_list);
560
561 /* Loop on 'freeing_list' for disarming and removing from kprobe hash list */
562 list_for_each_entry_safe(op, tmp, &freeing_list, list) {
563 /* Switching from detour code to origin */
564 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
565 /* Disarm probes if marked disabled and not gone */
566 if (kprobe_disabled(p: &op->kp) && !kprobe_gone(p: &op->kp))
567 arch_disarm_kprobe(p: &op->kp);
568 if (kprobe_unused(p: &op->kp)) {
569 /*
570 * Remove unused probes from hash list. After waiting
571 * for synchronization, these probes are reclaimed.
572 * (reclaiming is done by do_free_cleaned_kprobes().)
573 */
574 hlist_del_rcu(n: &op->kp.hlist);
575 } else
576 list_del_init(entry: &op->list);
577 }
578}
579
580/* Reclaim all kprobes on the 'freeing_list' */
581static void do_free_cleaned_kprobes(void)
582{
583 struct optimized_kprobe *op, *tmp;
584
585 list_for_each_entry_safe(op, tmp, &freeing_list, list) {
586 list_del_init(entry: &op->list);
587 if (WARN_ON_ONCE(!kprobe_unused(&op->kp))) {
588 /*
589 * This must not happen, but if there is a kprobe
590 * still in use, keep it on kprobes hash list.
591 */
592 continue;
593 }
594 free_aggr_kprobe(p: &op->kp);
595 }
596}
597
598/* Start optimizer after OPTIMIZE_DELAY passed */
599static void kick_kprobe_optimizer(void)
600{
601 schedule_delayed_work(dwork: &optimizing_work, OPTIMIZE_DELAY);
602}
603
604/* Kprobe jump optimizer */
605static void kprobe_optimizer(struct work_struct *work)
606{
607 mutex_lock(&kprobe_mutex);
608 cpus_read_lock();
609 mutex_lock(&text_mutex);
610
611 /*
612 * Step 1: Unoptimize kprobes and collect cleaned (unused and disarmed)
613 * kprobes before waiting for quiesence period.
614 */
615 do_unoptimize_kprobes();
616
617 /*
618 * Step 2: Wait for quiesence period to ensure all potentially
619 * preempted tasks to have normally scheduled. Because optprobe
620 * may modify multiple instructions, there is a chance that Nth
621 * instruction is preempted. In that case, such tasks can return
622 * to 2nd-Nth byte of jump instruction. This wait is for avoiding it.
623 * Note that on non-preemptive kernel, this is transparently converted
624 * to synchronoze_sched() to wait for all interrupts to have completed.
625 */
626 synchronize_rcu_tasks();
627
628 /* Step 3: Optimize kprobes after quiesence period */
629 do_optimize_kprobes();
630
631 /* Step 4: Free cleaned kprobes after quiesence period */
632 do_free_cleaned_kprobes();
633
634 mutex_unlock(lock: &text_mutex);
635 cpus_read_unlock();
636
637 /* Step 5: Kick optimizer again if needed */
638 if (!list_empty(head: &optimizing_list) || !list_empty(head: &unoptimizing_list))
639 kick_kprobe_optimizer();
640
641 mutex_unlock(lock: &kprobe_mutex);
642}
643
644/* Wait for completing optimization and unoptimization */
645void wait_for_kprobe_optimizer(void)
646{
647 mutex_lock(&kprobe_mutex);
648
649 while (!list_empty(head: &optimizing_list) || !list_empty(head: &unoptimizing_list)) {
650 mutex_unlock(lock: &kprobe_mutex);
651
652 /* This will also make 'optimizing_work' execute immmediately */
653 flush_delayed_work(dwork: &optimizing_work);
654 /* 'optimizing_work' might not have been queued yet, relax */
655 cpu_relax();
656
657 mutex_lock(&kprobe_mutex);
658 }
659
660 mutex_unlock(lock: &kprobe_mutex);
661}
662
663bool optprobe_queued_unopt(struct optimized_kprobe *op)
664{
665 struct optimized_kprobe *_op;
666
667 list_for_each_entry(_op, &unoptimizing_list, list) {
668 if (op == _op)
669 return true;
670 }
671
672 return false;
673}
674
675/* Optimize kprobe if p is ready to be optimized */
676static void optimize_kprobe(struct kprobe *p)
677{
678 struct optimized_kprobe *op;
679
680 /* Check if the kprobe is disabled or not ready for optimization. */
681 if (!kprobe_optready(p) || !kprobes_allow_optimization ||
682 (kprobe_disabled(p) || kprobes_all_disarmed))
683 return;
684
685 /* kprobes with 'post_handler' can not be optimized */
686 if (p->post_handler)
687 return;
688
689 op = container_of(p, struct optimized_kprobe, kp);
690
691 /* Check there is no other kprobes at the optimized instructions */
692 if (arch_check_optimized_kprobe(op) < 0)
693 return;
694
695 /* Check if it is already optimized. */
696 if (op->kp.flags & KPROBE_FLAG_OPTIMIZED) {
697 if (optprobe_queued_unopt(op)) {
698 /* This is under unoptimizing. Just dequeue the probe */
699 list_del_init(entry: &op->list);
700 }
701 return;
702 }
703 op->kp.flags |= KPROBE_FLAG_OPTIMIZED;
704
705 /*
706 * On the 'unoptimizing_list' and 'optimizing_list',
707 * 'op' must have OPTIMIZED flag
708 */
709 if (WARN_ON_ONCE(!list_empty(&op->list)))
710 return;
711
712 list_add(new: &op->list, head: &optimizing_list);
713 kick_kprobe_optimizer();
714}
715
716/* Short cut to direct unoptimizing */
717static void force_unoptimize_kprobe(struct optimized_kprobe *op)
718{
719 lockdep_assert_cpus_held();
720 arch_unoptimize_kprobe(op);
721 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
722}
723
724/* Unoptimize a kprobe if p is optimized */
725static void unoptimize_kprobe(struct kprobe *p, bool force)
726{
727 struct optimized_kprobe *op;
728
729 if (!kprobe_aggrprobe(p) || kprobe_disarmed(p))
730 return; /* This is not an optprobe nor optimized */
731
732 op = container_of(p, struct optimized_kprobe, kp);
733 if (!kprobe_optimized(p))
734 return;
735
736 if (!list_empty(head: &op->list)) {
737 if (optprobe_queued_unopt(op)) {
738 /* Queued in unoptimizing queue */
739 if (force) {
740 /*
741 * Forcibly unoptimize the kprobe here, and queue it
742 * in the freeing list for release afterwards.
743 */
744 force_unoptimize_kprobe(op);
745 list_move(list: &op->list, head: &freeing_list);
746 }
747 } else {
748 /* Dequeue from the optimizing queue */
749 list_del_init(entry: &op->list);
750 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
751 }
752 return;
753 }
754
755 /* Optimized kprobe case */
756 if (force) {
757 /* Forcibly update the code: this is a special case */
758 force_unoptimize_kprobe(op);
759 } else {
760 list_add(new: &op->list, head: &unoptimizing_list);
761 kick_kprobe_optimizer();
762 }
763}
764
765/* Cancel unoptimizing for reusing */
766static int reuse_unused_kprobe(struct kprobe *ap)
767{
768 struct optimized_kprobe *op;
769
770 /*
771 * Unused kprobe MUST be on the way of delayed unoptimizing (means
772 * there is still a relative jump) and disabled.
773 */
774 op = container_of(ap, struct optimized_kprobe, kp);
775 WARN_ON_ONCE(list_empty(&op->list));
776 /* Enable the probe again */
777 ap->flags &= ~KPROBE_FLAG_DISABLED;
778 /* Optimize it again. (remove from 'op->list') */
779 if (!kprobe_optready(p: ap))
780 return -EINVAL;
781
782 optimize_kprobe(p: ap);
783 return 0;
784}
785
786/* Remove optimized instructions */
787static void kill_optimized_kprobe(struct kprobe *p)
788{
789 struct optimized_kprobe *op;
790
791 op = container_of(p, struct optimized_kprobe, kp);
792 if (!list_empty(head: &op->list))
793 /* Dequeue from the (un)optimization queue */
794 list_del_init(entry: &op->list);
795 op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED;
796
797 if (kprobe_unused(p)) {
798 /*
799 * Unused kprobe is on unoptimizing or freeing list. We move it
800 * to freeing_list and let the kprobe_optimizer() remove it from
801 * the kprobe hash list and free it.
802 */
803 if (optprobe_queued_unopt(op))
804 list_move(list: &op->list, head: &freeing_list);
805 }
806
807 /* Don't touch the code, because it is already freed. */
808 arch_remove_optimized_kprobe(op);
809}
810
811static inline
812void __prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
813{
814 if (!kprobe_ftrace(p))
815 arch_prepare_optimized_kprobe(op, orig: p);
816}
817
818/* Try to prepare optimized instructions */
819static void prepare_optimized_kprobe(struct kprobe *p)
820{
821 struct optimized_kprobe *op;
822
823 op = container_of(p, struct optimized_kprobe, kp);
824 __prepare_optimized_kprobe(op, p);
825}
826
827/* Allocate new optimized_kprobe and try to prepare optimized instructions. */
828static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
829{
830 struct optimized_kprobe *op;
831
832 op = kzalloc(size: sizeof(struct optimized_kprobe), GFP_KERNEL);
833 if (!op)
834 return NULL;
835
836 INIT_LIST_HEAD(list: &op->list);
837 op->kp.addr = p->addr;
838 __prepare_optimized_kprobe(op, p);
839
840 return &op->kp;
841}
842
843static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p);
844
845/*
846 * Prepare an optimized_kprobe and optimize it.
847 * NOTE: 'p' must be a normal registered kprobe.
848 */
849static void try_to_optimize_kprobe(struct kprobe *p)
850{
851 struct kprobe *ap;
852 struct optimized_kprobe *op;
853
854 /* Impossible to optimize ftrace-based kprobe. */
855 if (kprobe_ftrace(p))
856 return;
857
858 /* For preparing optimization, jump_label_text_reserved() is called. */
859 cpus_read_lock();
860 jump_label_lock();
861 mutex_lock(&text_mutex);
862
863 ap = alloc_aggr_kprobe(p);
864 if (!ap)
865 goto out;
866
867 op = container_of(ap, struct optimized_kprobe, kp);
868 if (!arch_prepared_optinsn(optinsn: &op->optinsn)) {
869 /* If failed to setup optimizing, fallback to kprobe. */
870 arch_remove_optimized_kprobe(op);
871 kfree(objp: op);
872 goto out;
873 }
874
875 init_aggr_kprobe(ap, p);
876 optimize_kprobe(p: ap); /* This just kicks optimizer thread. */
877
878out:
879 mutex_unlock(lock: &text_mutex);
880 jump_label_unlock();
881 cpus_read_unlock();
882}
883
884static void optimize_all_kprobes(void)
885{
886 struct hlist_head *head;
887 struct kprobe *p;
888 unsigned int i;
889
890 mutex_lock(&kprobe_mutex);
891 /* If optimization is already allowed, just return. */
892 if (kprobes_allow_optimization)
893 goto out;
894
895 cpus_read_lock();
896 kprobes_allow_optimization = true;
897 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
898 head = &kprobe_table[i];
899 hlist_for_each_entry(p, head, hlist)
900 if (!kprobe_disabled(p))
901 optimize_kprobe(p);
902 }
903 cpus_read_unlock();
904 pr_info("kprobe jump-optimization is enabled. All kprobes are optimized if possible.\n");
905out:
906 mutex_unlock(lock: &kprobe_mutex);
907}
908
909#ifdef CONFIG_SYSCTL
910static void unoptimize_all_kprobes(void)
911{
912 struct hlist_head *head;
913 struct kprobe *p;
914 unsigned int i;
915
916 mutex_lock(&kprobe_mutex);
917 /* If optimization is already prohibited, just return. */
918 if (!kprobes_allow_optimization) {
919 mutex_unlock(lock: &kprobe_mutex);
920 return;
921 }
922
923 cpus_read_lock();
924 kprobes_allow_optimization = false;
925 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
926 head = &kprobe_table[i];
927 hlist_for_each_entry(p, head, hlist) {
928 if (!kprobe_disabled(p))
929 unoptimize_kprobe(p, force: false);
930 }
931 }
932 cpus_read_unlock();
933 mutex_unlock(lock: &kprobe_mutex);
934
935 /* Wait for unoptimizing completion. */
936 wait_for_kprobe_optimizer();
937 pr_info("kprobe jump-optimization is disabled. All kprobes are based on software breakpoint.\n");
938}
939
940static DEFINE_MUTEX(kprobe_sysctl_mutex);
941static int sysctl_kprobes_optimization;
942static int proc_kprobes_optimization_handler(struct ctl_table *table,
943 int write, void *buffer,
944 size_t *length, loff_t *ppos)
945{
946 int ret;
947
948 mutex_lock(&kprobe_sysctl_mutex);
949 sysctl_kprobes_optimization = kprobes_allow_optimization ? 1 : 0;
950 ret = proc_dointvec_minmax(table, write, buffer, length, ppos);
951
952 if (sysctl_kprobes_optimization)
953 optimize_all_kprobes();
954 else
955 unoptimize_all_kprobes();
956 mutex_unlock(lock: &kprobe_sysctl_mutex);
957
958 return ret;
959}
960
961static struct ctl_table kprobe_sysctls[] = {
962 {
963 .procname = "kprobes-optimization",
964 .data = &sysctl_kprobes_optimization,
965 .maxlen = sizeof(int),
966 .mode = 0644,
967 .proc_handler = proc_kprobes_optimization_handler,
968 .extra1 = SYSCTL_ZERO,
969 .extra2 = SYSCTL_ONE,
970 },
971 {}
972};
973
974static void __init kprobe_sysctls_init(void)
975{
976 register_sysctl_init("debug", kprobe_sysctls);
977}
978#endif /* CONFIG_SYSCTL */
979
980/* Put a breakpoint for a probe. */
981static void __arm_kprobe(struct kprobe *p)
982{
983 struct kprobe *_p;
984
985 lockdep_assert_held(&text_mutex);
986
987 /* Find the overlapping optimized kprobes. */
988 _p = get_optimized_kprobe(addr: p->addr);
989 if (unlikely(_p))
990 /* Fallback to unoptimized kprobe */
991 unoptimize_kprobe(p: _p, force: true);
992
993 arch_arm_kprobe(p);
994 optimize_kprobe(p); /* Try to optimize (add kprobe to a list) */
995}
996
997/* Remove the breakpoint of a probe. */
998static void __disarm_kprobe(struct kprobe *p, bool reopt)
999{
1000 struct kprobe *_p;
1001
1002 lockdep_assert_held(&text_mutex);
1003
1004 /* Try to unoptimize */
1005 unoptimize_kprobe(p, force: kprobes_all_disarmed);
1006
1007 if (!kprobe_queued(p)) {
1008 arch_disarm_kprobe(p);
1009 /* If another kprobe was blocked, re-optimize it. */
1010 _p = get_optimized_kprobe(addr: p->addr);
1011 if (unlikely(_p) && reopt)
1012 optimize_kprobe(p: _p);
1013 }
1014 /*
1015 * TODO: Since unoptimization and real disarming will be done by
1016 * the worker thread, we can not check whether another probe are
1017 * unoptimized because of this probe here. It should be re-optimized
1018 * by the worker thread.
1019 */
1020}
1021
1022#else /* !CONFIG_OPTPROBES */
1023
1024#define optimize_kprobe(p) do {} while (0)
1025#define unoptimize_kprobe(p, f) do {} while (0)
1026#define kill_optimized_kprobe(p) do {} while (0)
1027#define prepare_optimized_kprobe(p) do {} while (0)
1028#define try_to_optimize_kprobe(p) do {} while (0)
1029#define __arm_kprobe(p) arch_arm_kprobe(p)
1030#define __disarm_kprobe(p, o) arch_disarm_kprobe(p)
1031#define kprobe_disarmed(p) kprobe_disabled(p)
1032#define wait_for_kprobe_optimizer() do {} while (0)
1033
1034static int reuse_unused_kprobe(struct kprobe *ap)
1035{
1036 /*
1037 * If the optimized kprobe is NOT supported, the aggr kprobe is
1038 * released at the same time that the last aggregated kprobe is
1039 * unregistered.
1040 * Thus there should be no chance to reuse unused kprobe.
1041 */
1042 WARN_ON_ONCE(1);
1043 return -EINVAL;
1044}
1045
1046static void free_aggr_kprobe(struct kprobe *p)
1047{
1048 arch_remove_kprobe(p);
1049 kfree(p);
1050}
1051
1052static struct kprobe *alloc_aggr_kprobe(struct kprobe *p)
1053{
1054 return kzalloc(sizeof(struct kprobe), GFP_KERNEL);
1055}
1056#endif /* CONFIG_OPTPROBES */
1057
1058#ifdef CONFIG_KPROBES_ON_FTRACE
1059static struct ftrace_ops kprobe_ftrace_ops __read_mostly = {
1060 .func = kprobe_ftrace_handler,
1061 .flags = FTRACE_OPS_FL_SAVE_REGS,
1062};
1063
1064static struct ftrace_ops kprobe_ipmodify_ops __read_mostly = {
1065 .func = kprobe_ftrace_handler,
1066 .flags = FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_IPMODIFY,
1067};
1068
1069static int kprobe_ipmodify_enabled;
1070static int kprobe_ftrace_enabled;
1071
1072static int __arm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
1073 int *cnt)
1074{
1075 int ret;
1076
1077 lockdep_assert_held(&kprobe_mutex);
1078
1079 ret = ftrace_set_filter_ip(ops, ip: (unsigned long)p->addr, remove: 0, reset: 0);
1080 if (WARN_ONCE(ret < 0, "Failed to arm kprobe-ftrace at %pS (error %d)\n", p->addr, ret))
1081 return ret;
1082
1083 if (*cnt == 0) {
1084 ret = register_ftrace_function(ops);
1085 if (WARN(ret < 0, "Failed to register kprobe-ftrace (error %d)\n", ret))
1086 goto err_ftrace;
1087 }
1088
1089 (*cnt)++;
1090 return ret;
1091
1092err_ftrace:
1093 /*
1094 * At this point, sinec ops is not registered, we should be sefe from
1095 * registering empty filter.
1096 */
1097 ftrace_set_filter_ip(ops, ip: (unsigned long)p->addr, remove: 1, reset: 0);
1098 return ret;
1099}
1100
1101static int arm_kprobe_ftrace(struct kprobe *p)
1102{
1103 bool ipmodify = (p->post_handler != NULL);
1104
1105 return __arm_kprobe_ftrace(p,
1106 ops: ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
1107 cnt: ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
1108}
1109
1110static int __disarm_kprobe_ftrace(struct kprobe *p, struct ftrace_ops *ops,
1111 int *cnt)
1112{
1113 int ret;
1114
1115 lockdep_assert_held(&kprobe_mutex);
1116
1117 if (*cnt == 1) {
1118 ret = unregister_ftrace_function(ops);
1119 if (WARN(ret < 0, "Failed to unregister kprobe-ftrace (error %d)\n", ret))
1120 return ret;
1121 }
1122
1123 (*cnt)--;
1124
1125 ret = ftrace_set_filter_ip(ops, ip: (unsigned long)p->addr, remove: 1, reset: 0);
1126 WARN_ONCE(ret < 0, "Failed to disarm kprobe-ftrace at %pS (error %d)\n",
1127 p->addr, ret);
1128 return ret;
1129}
1130
1131static int disarm_kprobe_ftrace(struct kprobe *p)
1132{
1133 bool ipmodify = (p->post_handler != NULL);
1134
1135 return __disarm_kprobe_ftrace(p,
1136 ops: ipmodify ? &kprobe_ipmodify_ops : &kprobe_ftrace_ops,
1137 cnt: ipmodify ? &kprobe_ipmodify_enabled : &kprobe_ftrace_enabled);
1138}
1139#else /* !CONFIG_KPROBES_ON_FTRACE */
1140static inline int arm_kprobe_ftrace(struct kprobe *p)
1141{
1142 return -ENODEV;
1143}
1144
1145static inline int disarm_kprobe_ftrace(struct kprobe *p)
1146{
1147 return -ENODEV;
1148}
1149#endif
1150
1151static int prepare_kprobe(struct kprobe *p)
1152{
1153 /* Must ensure p->addr is really on ftrace */
1154 if (kprobe_ftrace(p))
1155 return arch_prepare_kprobe_ftrace(p);
1156
1157 return arch_prepare_kprobe(p);
1158}
1159
1160static int arm_kprobe(struct kprobe *kp)
1161{
1162 if (unlikely(kprobe_ftrace(kp)))
1163 return arm_kprobe_ftrace(p: kp);
1164
1165 cpus_read_lock();
1166 mutex_lock(&text_mutex);
1167 __arm_kprobe(p: kp);
1168 mutex_unlock(lock: &text_mutex);
1169 cpus_read_unlock();
1170
1171 return 0;
1172}
1173
1174static int disarm_kprobe(struct kprobe *kp, bool reopt)
1175{
1176 if (unlikely(kprobe_ftrace(kp)))
1177 return disarm_kprobe_ftrace(p: kp);
1178
1179 cpus_read_lock();
1180 mutex_lock(&text_mutex);
1181 __disarm_kprobe(p: kp, reopt);
1182 mutex_unlock(lock: &text_mutex);
1183 cpus_read_unlock();
1184
1185 return 0;
1186}
1187
1188/*
1189 * Aggregate handlers for multiple kprobes support - these handlers
1190 * take care of invoking the individual kprobe handlers on p->list
1191 */
1192static int aggr_pre_handler(struct kprobe *p, struct pt_regs *regs)
1193{
1194 struct kprobe *kp;
1195
1196 list_for_each_entry_rcu(kp, &p->list, list) {
1197 if (kp->pre_handler && likely(!kprobe_disabled(kp))) {
1198 set_kprobe_instance(kp);
1199 if (kp->pre_handler(kp, regs))
1200 return 1;
1201 }
1202 reset_kprobe_instance();
1203 }
1204 return 0;
1205}
1206NOKPROBE_SYMBOL(aggr_pre_handler);
1207
1208static void aggr_post_handler(struct kprobe *p, struct pt_regs *regs,
1209 unsigned long flags)
1210{
1211 struct kprobe *kp;
1212
1213 list_for_each_entry_rcu(kp, &p->list, list) {
1214 if (kp->post_handler && likely(!kprobe_disabled(kp))) {
1215 set_kprobe_instance(kp);
1216 kp->post_handler(kp, regs, flags);
1217 reset_kprobe_instance();
1218 }
1219 }
1220}
1221NOKPROBE_SYMBOL(aggr_post_handler);
1222
1223/* Walks the list and increments 'nmissed' if 'p' has child probes. */
1224void kprobes_inc_nmissed_count(struct kprobe *p)
1225{
1226 struct kprobe *kp;
1227
1228 if (!kprobe_aggrprobe(p)) {
1229 p->nmissed++;
1230 } else {
1231 list_for_each_entry_rcu(kp, &p->list, list)
1232 kp->nmissed++;
1233 }
1234}
1235NOKPROBE_SYMBOL(kprobes_inc_nmissed_count);
1236
1237static struct kprobe kprobe_busy = {
1238 .addr = (void *) get_kprobe,
1239};
1240
1241void kprobe_busy_begin(void)
1242{
1243 struct kprobe_ctlblk *kcb;
1244
1245 preempt_disable();
1246 __this_cpu_write(current_kprobe, &kprobe_busy);
1247 kcb = get_kprobe_ctlblk();
1248 kcb->kprobe_status = KPROBE_HIT_ACTIVE;
1249}
1250
1251void kprobe_busy_end(void)
1252{
1253 __this_cpu_write(current_kprobe, NULL);
1254 preempt_enable();
1255}
1256
1257/* Add the new probe to 'ap->list'. */
1258static int add_new_kprobe(struct kprobe *ap, struct kprobe *p)
1259{
1260 if (p->post_handler)
1261 unoptimize_kprobe(p: ap, force: true); /* Fall back to normal kprobe */
1262
1263 list_add_rcu(new: &p->list, head: &ap->list);
1264 if (p->post_handler && !ap->post_handler)
1265 ap->post_handler = aggr_post_handler;
1266
1267 return 0;
1268}
1269
1270/*
1271 * Fill in the required fields of the aggregator kprobe. Replace the
1272 * earlier kprobe in the hlist with the aggregator kprobe.
1273 */
1274static void init_aggr_kprobe(struct kprobe *ap, struct kprobe *p)
1275{
1276 /* Copy the insn slot of 'p' to 'ap'. */
1277 copy_kprobe(ap: p, p: ap);
1278 flush_insn_slot(ap);
1279 ap->addr = p->addr;
1280 ap->flags = p->flags & ~KPROBE_FLAG_OPTIMIZED;
1281 ap->pre_handler = aggr_pre_handler;
1282 /* We don't care the kprobe which has gone. */
1283 if (p->post_handler && !kprobe_gone(p))
1284 ap->post_handler = aggr_post_handler;
1285
1286 INIT_LIST_HEAD(list: &ap->list);
1287 INIT_HLIST_NODE(h: &ap->hlist);
1288
1289 list_add_rcu(new: &p->list, head: &ap->list);
1290 hlist_replace_rcu(old: &p->hlist, new: &ap->hlist);
1291}
1292
1293/*
1294 * This registers the second or subsequent kprobe at the same address.
1295 */
1296static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
1297{
1298 int ret = 0;
1299 struct kprobe *ap = orig_p;
1300
1301 cpus_read_lock();
1302
1303 /* For preparing optimization, jump_label_text_reserved() is called */
1304 jump_label_lock();
1305 mutex_lock(&text_mutex);
1306
1307 if (!kprobe_aggrprobe(p: orig_p)) {
1308 /* If 'orig_p' is not an 'aggr_kprobe', create new one. */
1309 ap = alloc_aggr_kprobe(p: orig_p);
1310 if (!ap) {
1311 ret = -ENOMEM;
1312 goto out;
1313 }
1314 init_aggr_kprobe(ap, p: orig_p);
1315 } else if (kprobe_unused(p: ap)) {
1316 /* This probe is going to die. Rescue it */
1317 ret = reuse_unused_kprobe(ap);
1318 if (ret)
1319 goto out;
1320 }
1321
1322 if (kprobe_gone(p: ap)) {
1323 /*
1324 * Attempting to insert new probe at the same location that
1325 * had a probe in the module vaddr area which already
1326 * freed. So, the instruction slot has already been
1327 * released. We need a new slot for the new probe.
1328 */
1329 ret = arch_prepare_kprobe(p: ap);
1330 if (ret)
1331 /*
1332 * Even if fail to allocate new slot, don't need to
1333 * free the 'ap'. It will be used next time, or
1334 * freed by unregister_kprobe().
1335 */
1336 goto out;
1337
1338 /* Prepare optimized instructions if possible. */
1339 prepare_optimized_kprobe(p: ap);
1340
1341 /*
1342 * Clear gone flag to prevent allocating new slot again, and
1343 * set disabled flag because it is not armed yet.
1344 */
1345 ap->flags = (ap->flags & ~KPROBE_FLAG_GONE)
1346 | KPROBE_FLAG_DISABLED;
1347 }
1348
1349 /* Copy the insn slot of 'p' to 'ap'. */
1350 copy_kprobe(ap, p);
1351 ret = add_new_kprobe(ap, p);
1352
1353out:
1354 mutex_unlock(lock: &text_mutex);
1355 jump_label_unlock();
1356 cpus_read_unlock();
1357
1358 if (ret == 0 && kprobe_disabled(p: ap) && !kprobe_disabled(p)) {
1359 ap->flags &= ~KPROBE_FLAG_DISABLED;
1360 if (!kprobes_all_disarmed) {
1361 /* Arm the breakpoint again. */
1362 ret = arm_kprobe(kp: ap);
1363 if (ret) {
1364 ap->flags |= KPROBE_FLAG_DISABLED;
1365 list_del_rcu(entry: &p->list);
1366 synchronize_rcu();
1367 }
1368 }
1369 }
1370 return ret;
1371}
1372
1373bool __weak arch_within_kprobe_blacklist(unsigned long addr)
1374{
1375 /* The '__kprobes' functions and entry code must not be probed. */
1376 return addr >= (unsigned long)__kprobes_text_start &&
1377 addr < (unsigned long)__kprobes_text_end;
1378}
1379
1380static bool __within_kprobe_blacklist(unsigned long addr)
1381{
1382 struct kprobe_blacklist_entry *ent;
1383
1384 if (arch_within_kprobe_blacklist(addr))
1385 return true;
1386 /*
1387 * If 'kprobe_blacklist' is defined, check the address and
1388 * reject any probe registration in the prohibited area.
1389 */
1390 list_for_each_entry(ent, &kprobe_blacklist, list) {
1391 if (addr >= ent->start_addr && addr < ent->end_addr)
1392 return true;
1393 }
1394 return false;
1395}
1396
1397bool within_kprobe_blacklist(unsigned long addr)
1398{
1399 char symname[KSYM_NAME_LEN], *p;
1400
1401 if (__within_kprobe_blacklist(addr))
1402 return true;
1403
1404 /* Check if the address is on a suffixed-symbol */
1405 if (!lookup_symbol_name(addr, symname)) {
1406 p = strchr(symname, '.');
1407 if (!p)
1408 return false;
1409 *p = '\0';
1410 addr = (unsigned long)kprobe_lookup_name(name: symname, unused: 0);
1411 if (addr)
1412 return __within_kprobe_blacklist(addr);
1413 }
1414 return false;
1415}
1416
1417/*
1418 * arch_adjust_kprobe_addr - adjust the address
1419 * @addr: symbol base address
1420 * @offset: offset within the symbol
1421 * @on_func_entry: was this @addr+@offset on the function entry
1422 *
1423 * Typically returns @addr + @offset, except for special cases where the
1424 * function might be prefixed by a CFI landing pad, in that case any offset
1425 * inside the landing pad is mapped to the first 'real' instruction of the
1426 * symbol.
1427 *
1428 * Specifically, for things like IBT/BTI, skip the resp. ENDBR/BTI.C
1429 * instruction at +0.
1430 */
1431kprobe_opcode_t *__weak arch_adjust_kprobe_addr(unsigned long addr,
1432 unsigned long offset,
1433 bool *on_func_entry)
1434{
1435 *on_func_entry = !offset;
1436 return (kprobe_opcode_t *)(addr + offset);
1437}
1438
1439/*
1440 * If 'symbol_name' is specified, look it up and add the 'offset'
1441 * to it. This way, we can specify a relative address to a symbol.
1442 * This returns encoded errors if it fails to look up symbol or invalid
1443 * combination of parameters.
1444 */
1445static kprobe_opcode_t *
1446_kprobe_addr(kprobe_opcode_t *addr, const char *symbol_name,
1447 unsigned long offset, bool *on_func_entry)
1448{
1449 if ((symbol_name && addr) || (!symbol_name && !addr))
1450 goto invalid;
1451
1452 if (symbol_name) {
1453 /*
1454 * Input: @sym + @offset
1455 * Output: @addr + @offset
1456 *
1457 * NOTE: kprobe_lookup_name() does *NOT* fold the offset
1458 * argument into it's output!
1459 */
1460 addr = kprobe_lookup_name(name: symbol_name, unused: offset);
1461 if (!addr)
1462 return ERR_PTR(error: -ENOENT);
1463 }
1464
1465 /*
1466 * So here we have @addr + @offset, displace it into a new
1467 * @addr' + @offset' where @addr' is the symbol start address.
1468 */
1469 addr = (void *)addr + offset;
1470 if (!kallsyms_lookup_size_offset(addr: (unsigned long)addr, NULL, offset: &offset))
1471 return ERR_PTR(error: -ENOENT);
1472 addr = (void *)addr - offset;
1473
1474 /*
1475 * Then ask the architecture to re-combine them, taking care of
1476 * magical function entry details while telling us if this was indeed
1477 * at the start of the function.
1478 */
1479 addr = arch_adjust_kprobe_addr(addr: (unsigned long)addr, offset, on_func_entry);
1480 if (addr)
1481 return addr;
1482
1483invalid:
1484 return ERR_PTR(error: -EINVAL);
1485}
1486
1487static kprobe_opcode_t *kprobe_addr(struct kprobe *p)
1488{
1489 bool on_func_entry;
1490 return _kprobe_addr(addr: p->addr, symbol_name: p->symbol_name, offset: p->offset, on_func_entry: &on_func_entry);
1491}
1492
1493/*
1494 * Check the 'p' is valid and return the aggregator kprobe
1495 * at the same address.
1496 */
1497static struct kprobe *__get_valid_kprobe(struct kprobe *p)
1498{
1499 struct kprobe *ap, *list_p;
1500
1501 lockdep_assert_held(&kprobe_mutex);
1502
1503 ap = get_kprobe(addr: p->addr);
1504 if (unlikely(!ap))
1505 return NULL;
1506
1507 if (p != ap) {
1508 list_for_each_entry(list_p, &ap->list, list)
1509 if (list_p == p)
1510 /* kprobe p is a valid probe */
1511 goto valid;
1512 return NULL;
1513 }
1514valid:
1515 return ap;
1516}
1517
1518/*
1519 * Warn and return error if the kprobe is being re-registered since
1520 * there must be a software bug.
1521 */
1522static inline int warn_kprobe_rereg(struct kprobe *p)
1523{
1524 int ret = 0;
1525
1526 mutex_lock(&kprobe_mutex);
1527 if (WARN_ON_ONCE(__get_valid_kprobe(p)))
1528 ret = -EINVAL;
1529 mutex_unlock(lock: &kprobe_mutex);
1530
1531 return ret;
1532}
1533
1534static int check_ftrace_location(struct kprobe *p)
1535{
1536 unsigned long addr = (unsigned long)p->addr;
1537
1538 if (ftrace_location(ip: addr) == addr) {
1539#ifdef CONFIG_KPROBES_ON_FTRACE
1540 p->flags |= KPROBE_FLAG_FTRACE;
1541#else /* !CONFIG_KPROBES_ON_FTRACE */
1542 return -EINVAL;
1543#endif
1544 }
1545 return 0;
1546}
1547
1548static bool is_cfi_preamble_symbol(unsigned long addr)
1549{
1550 char symbuf[KSYM_NAME_LEN];
1551
1552 if (lookup_symbol_name(addr, symname: symbuf))
1553 return false;
1554
1555 return str_has_prefix(str: "__cfi_", prefix: symbuf) ||
1556 str_has_prefix(str: "__pfx_", prefix: symbuf);
1557}
1558
1559static int check_kprobe_address_safe(struct kprobe *p,
1560 struct module **probed_mod)
1561{
1562 int ret;
1563
1564 ret = check_ftrace_location(p);
1565 if (ret)
1566 return ret;
1567 jump_label_lock();
1568 preempt_disable();
1569
1570 /* Ensure the address is in a text area, and find a module if exists. */
1571 *probed_mod = NULL;
1572 if (!core_kernel_text(addr: (unsigned long) p->addr)) {
1573 *probed_mod = __module_text_address(addr: (unsigned long) p->addr);
1574 if (!(*probed_mod)) {
1575 ret = -EINVAL;
1576 goto out;
1577 }
1578 }
1579 /* Ensure it is not in reserved area. */
1580 if (in_gate_area_no_mm(addr: (unsigned long) p->addr) ||
1581 within_kprobe_blacklist(addr: (unsigned long) p->addr) ||
1582 jump_label_text_reserved(start: p->addr, end: p->addr) ||
1583 static_call_text_reserved(start: p->addr, end: p->addr) ||
1584 find_bug(bugaddr: (unsigned long)p->addr) ||
1585 is_cfi_preamble_symbol(addr: (unsigned long)p->addr)) {
1586 ret = -EINVAL;
1587 goto out;
1588 }
1589
1590 /* Get module refcount and reject __init functions for loaded modules. */
1591 if (*probed_mod) {
1592 /*
1593 * We must hold a refcount of the probed module while updating
1594 * its code to prohibit unexpected unloading.
1595 */
1596 if (unlikely(!try_module_get(*probed_mod))) {
1597 ret = -ENOENT;
1598 goto out;
1599 }
1600
1601 /*
1602 * If the module freed '.init.text', we couldn't insert
1603 * kprobes in there.
1604 */
1605 if (within_module_init(addr: (unsigned long)p->addr, mod: *probed_mod) &&
1606 (*probed_mod)->state != MODULE_STATE_COMING) {
1607 module_put(module: *probed_mod);
1608 *probed_mod = NULL;
1609 ret = -ENOENT;
1610 }
1611 }
1612out:
1613 preempt_enable();
1614 jump_label_unlock();
1615
1616 return ret;
1617}
1618
1619int register_kprobe(struct kprobe *p)
1620{
1621 int ret;
1622 struct kprobe *old_p;
1623 struct module *probed_mod;
1624 kprobe_opcode_t *addr;
1625 bool on_func_entry;
1626
1627 /* Adjust probe address from symbol */
1628 addr = _kprobe_addr(addr: p->addr, symbol_name: p->symbol_name, offset: p->offset, on_func_entry: &on_func_entry);
1629 if (IS_ERR(ptr: addr))
1630 return PTR_ERR(ptr: addr);
1631 p->addr = addr;
1632
1633 ret = warn_kprobe_rereg(p);
1634 if (ret)
1635 return ret;
1636
1637 /* User can pass only KPROBE_FLAG_DISABLED to register_kprobe */
1638 p->flags &= KPROBE_FLAG_DISABLED;
1639 p->nmissed = 0;
1640 INIT_LIST_HEAD(list: &p->list);
1641
1642 ret = check_kprobe_address_safe(p, probed_mod: &probed_mod);
1643 if (ret)
1644 return ret;
1645
1646 mutex_lock(&kprobe_mutex);
1647
1648 if (on_func_entry)
1649 p->flags |= KPROBE_FLAG_ON_FUNC_ENTRY;
1650
1651 old_p = get_kprobe(addr: p->addr);
1652 if (old_p) {
1653 /* Since this may unoptimize 'old_p', locking 'text_mutex'. */
1654 ret = register_aggr_kprobe(orig_p: old_p, p);
1655 goto out;
1656 }
1657
1658 cpus_read_lock();
1659 /* Prevent text modification */
1660 mutex_lock(&text_mutex);
1661 ret = prepare_kprobe(p);
1662 mutex_unlock(lock: &text_mutex);
1663 cpus_read_unlock();
1664 if (ret)
1665 goto out;
1666
1667 INIT_HLIST_NODE(h: &p->hlist);
1668 hlist_add_head_rcu(n: &p->hlist,
1669 h: &kprobe_table[hash_ptr(ptr: p->addr, KPROBE_HASH_BITS)]);
1670
1671 if (!kprobes_all_disarmed && !kprobe_disabled(p)) {
1672 ret = arm_kprobe(kp: p);
1673 if (ret) {
1674 hlist_del_rcu(n: &p->hlist);
1675 synchronize_rcu();
1676 goto out;
1677 }
1678 }
1679
1680 /* Try to optimize kprobe */
1681 try_to_optimize_kprobe(p);
1682out:
1683 mutex_unlock(lock: &kprobe_mutex);
1684
1685 if (probed_mod)
1686 module_put(module: probed_mod);
1687
1688 return ret;
1689}
1690EXPORT_SYMBOL_GPL(register_kprobe);
1691
1692/* Check if all probes on the 'ap' are disabled. */
1693static bool aggr_kprobe_disabled(struct kprobe *ap)
1694{
1695 struct kprobe *kp;
1696
1697 lockdep_assert_held(&kprobe_mutex);
1698
1699 list_for_each_entry(kp, &ap->list, list)
1700 if (!kprobe_disabled(p: kp))
1701 /*
1702 * Since there is an active probe on the list,
1703 * we can't disable this 'ap'.
1704 */
1705 return false;
1706
1707 return true;
1708}
1709
1710static struct kprobe *__disable_kprobe(struct kprobe *p)
1711{
1712 struct kprobe *orig_p;
1713 int ret;
1714
1715 lockdep_assert_held(&kprobe_mutex);
1716
1717 /* Get an original kprobe for return */
1718 orig_p = __get_valid_kprobe(p);
1719 if (unlikely(orig_p == NULL))
1720 return ERR_PTR(error: -EINVAL);
1721
1722 if (!kprobe_disabled(p)) {
1723 /* Disable probe if it is a child probe */
1724 if (p != orig_p)
1725 p->flags |= KPROBE_FLAG_DISABLED;
1726
1727 /* Try to disarm and disable this/parent probe */
1728 if (p == orig_p || aggr_kprobe_disabled(ap: orig_p)) {
1729 /*
1730 * Don't be lazy here. Even if 'kprobes_all_disarmed'
1731 * is false, 'orig_p' might not have been armed yet.
1732 * Note arm_all_kprobes() __tries__ to arm all kprobes
1733 * on the best effort basis.
1734 */
1735 if (!kprobes_all_disarmed && !kprobe_disabled(p: orig_p)) {
1736 ret = disarm_kprobe(kp: orig_p, reopt: true);
1737 if (ret) {
1738 p->flags &= ~KPROBE_FLAG_DISABLED;
1739 return ERR_PTR(error: ret);
1740 }
1741 }
1742 orig_p->flags |= KPROBE_FLAG_DISABLED;
1743 }
1744 }
1745
1746 return orig_p;
1747}
1748
1749/*
1750 * Unregister a kprobe without a scheduler synchronization.
1751 */
1752static int __unregister_kprobe_top(struct kprobe *p)
1753{
1754 struct kprobe *ap, *list_p;
1755
1756 /* Disable kprobe. This will disarm it if needed. */
1757 ap = __disable_kprobe(p);
1758 if (IS_ERR(ptr: ap))
1759 return PTR_ERR(ptr: ap);
1760
1761 if (ap == p)
1762 /*
1763 * This probe is an independent(and non-optimized) kprobe
1764 * (not an aggrprobe). Remove from the hash list.
1765 */
1766 goto disarmed;
1767
1768 /* Following process expects this probe is an aggrprobe */
1769 WARN_ON(!kprobe_aggrprobe(ap));
1770
1771 if (list_is_singular(head: &ap->list) && kprobe_disarmed(p: ap))
1772 /*
1773 * !disarmed could be happen if the probe is under delayed
1774 * unoptimizing.
1775 */
1776 goto disarmed;
1777 else {
1778 /* If disabling probe has special handlers, update aggrprobe */
1779 if (p->post_handler && !kprobe_gone(p)) {
1780 list_for_each_entry(list_p, &ap->list, list) {
1781 if ((list_p != p) && (list_p->post_handler))
1782 goto noclean;
1783 }
1784 /*
1785 * For the kprobe-on-ftrace case, we keep the
1786 * post_handler setting to identify this aggrprobe
1787 * armed with kprobe_ipmodify_ops.
1788 */
1789 if (!kprobe_ftrace(p: ap))
1790 ap->post_handler = NULL;
1791 }
1792noclean:
1793 /*
1794 * Remove from the aggrprobe: this path will do nothing in
1795 * __unregister_kprobe_bottom().
1796 */
1797 list_del_rcu(entry: &p->list);
1798 if (!kprobe_disabled(p: ap) && !kprobes_all_disarmed)
1799 /*
1800 * Try to optimize this probe again, because post
1801 * handler may have been changed.
1802 */
1803 optimize_kprobe(p: ap);
1804 }
1805 return 0;
1806
1807disarmed:
1808 hlist_del_rcu(n: &ap->hlist);
1809 return 0;
1810}
1811
1812static void __unregister_kprobe_bottom(struct kprobe *p)
1813{
1814 struct kprobe *ap;
1815
1816 if (list_empty(head: &p->list))
1817 /* This is an independent kprobe */
1818 arch_remove_kprobe(p);
1819 else if (list_is_singular(head: &p->list)) {
1820 /* This is the last child of an aggrprobe */
1821 ap = list_entry(p->list.next, struct kprobe, list);
1822 list_del(entry: &p->list);
1823 free_aggr_kprobe(p: ap);
1824 }
1825 /* Otherwise, do nothing. */
1826}
1827
1828int register_kprobes(struct kprobe **kps, int num)
1829{
1830 int i, ret = 0;
1831
1832 if (num <= 0)
1833 return -EINVAL;
1834 for (i = 0; i < num; i++) {
1835 ret = register_kprobe(kps[i]);
1836 if (ret < 0) {
1837 if (i > 0)
1838 unregister_kprobes(kps, num: i);
1839 break;
1840 }
1841 }
1842 return ret;
1843}
1844EXPORT_SYMBOL_GPL(register_kprobes);
1845
1846void unregister_kprobe(struct kprobe *p)
1847{
1848 unregister_kprobes(kps: &p, num: 1);
1849}
1850EXPORT_SYMBOL_GPL(unregister_kprobe);
1851
1852void unregister_kprobes(struct kprobe **kps, int num)
1853{
1854 int i;
1855
1856 if (num <= 0)
1857 return;
1858 mutex_lock(&kprobe_mutex);
1859 for (i = 0; i < num; i++)
1860 if (__unregister_kprobe_top(p: kps[i]) < 0)
1861 kps[i]->addr = NULL;
1862 mutex_unlock(lock: &kprobe_mutex);
1863
1864 synchronize_rcu();
1865 for (i = 0; i < num; i++)
1866 if (kps[i]->addr)
1867 __unregister_kprobe_bottom(p: kps[i]);
1868}
1869EXPORT_SYMBOL_GPL(unregister_kprobes);
1870
1871int __weak kprobe_exceptions_notify(struct notifier_block *self,
1872 unsigned long val, void *data)
1873{
1874 return NOTIFY_DONE;
1875}
1876NOKPROBE_SYMBOL(kprobe_exceptions_notify);
1877
1878static struct notifier_block kprobe_exceptions_nb = {
1879 .notifier_call = kprobe_exceptions_notify,
1880 .priority = 0x7fffffff /* we need to be notified first */
1881};
1882
1883#ifdef CONFIG_KRETPROBES
1884
1885#if !defined(CONFIG_KRETPROBE_ON_RETHOOK)
1886
1887/* callbacks for objpool of kretprobe instances */
1888static int kretprobe_init_inst(void *nod, void *context)
1889{
1890 struct kretprobe_instance *ri = nod;
1891
1892 ri->rph = context;
1893 return 0;
1894}
1895static int kretprobe_fini_pool(struct objpool_head *head, void *context)
1896{
1897 kfree(context);
1898 return 0;
1899}
1900
1901static void free_rp_inst_rcu(struct rcu_head *head)
1902{
1903 struct kretprobe_instance *ri = container_of(head, struct kretprobe_instance, rcu);
1904 struct kretprobe_holder *rph = ri->rph;
1905
1906 objpool_drop(ri, &rph->pool);
1907}
1908NOKPROBE_SYMBOL(free_rp_inst_rcu);
1909
1910static void recycle_rp_inst(struct kretprobe_instance *ri)
1911{
1912 struct kretprobe *rp = get_kretprobe(ri);
1913
1914 if (likely(rp))
1915 objpool_push(ri, &rp->rph->pool);
1916 else
1917 call_rcu(&ri->rcu, free_rp_inst_rcu);
1918}
1919NOKPROBE_SYMBOL(recycle_rp_inst);
1920
1921/*
1922 * This function is called from delayed_put_task_struct() when a task is
1923 * dead and cleaned up to recycle any kretprobe instances associated with
1924 * this task. These left over instances represent probed functions that
1925 * have been called but will never return.
1926 */
1927void kprobe_flush_task(struct task_struct *tk)
1928{
1929 struct kretprobe_instance *ri;
1930 struct llist_node *node;
1931
1932 /* Early boot, not yet initialized. */
1933 if (unlikely(!kprobes_initialized))
1934 return;
1935
1936 kprobe_busy_begin();
1937
1938 node = __llist_del_all(&tk->kretprobe_instances);
1939 while (node) {
1940 ri = container_of(node, struct kretprobe_instance, llist);
1941 node = node->next;
1942
1943 recycle_rp_inst(ri);
1944 }
1945
1946 kprobe_busy_end();
1947}
1948NOKPROBE_SYMBOL(kprobe_flush_task);
1949
1950static inline void free_rp_inst(struct kretprobe *rp)
1951{
1952 struct kretprobe_holder *rph = rp->rph;
1953
1954 if (!rph)
1955 return;
1956 rp->rph = NULL;
1957 objpool_fini(&rph->pool);
1958}
1959
1960/* This assumes the 'tsk' is the current task or the is not running. */
1961static kprobe_opcode_t *__kretprobe_find_ret_addr(struct task_struct *tsk,
1962 struct llist_node **cur)
1963{
1964 struct kretprobe_instance *ri = NULL;
1965 struct llist_node *node = *cur;
1966
1967 if (!node)
1968 node = tsk->kretprobe_instances.first;
1969 else
1970 node = node->next;
1971
1972 while (node) {
1973 ri = container_of(node, struct kretprobe_instance, llist);
1974 if (ri->ret_addr != kretprobe_trampoline_addr()) {
1975 *cur = node;
1976 return ri->ret_addr;
1977 }
1978 node = node->next;
1979 }
1980 return NULL;
1981}
1982NOKPROBE_SYMBOL(__kretprobe_find_ret_addr);
1983
1984/**
1985 * kretprobe_find_ret_addr -- Find correct return address modified by kretprobe
1986 * @tsk: Target task
1987 * @fp: A frame pointer
1988 * @cur: a storage of the loop cursor llist_node pointer for next call
1989 *
1990 * Find the correct return address modified by a kretprobe on @tsk in unsigned
1991 * long type. If it finds the return address, this returns that address value,
1992 * or this returns 0.
1993 * The @tsk must be 'current' or a task which is not running. @fp is a hint
1994 * to get the currect return address - which is compared with the
1995 * kretprobe_instance::fp field. The @cur is a loop cursor for searching the
1996 * kretprobe return addresses on the @tsk. The '*@cur' should be NULL at the
1997 * first call, but '@cur' itself must NOT NULL.
1998 */
1999unsigned long kretprobe_find_ret_addr(struct task_struct *tsk, void *fp,
2000 struct llist_node **cur)
2001{
2002 struct kretprobe_instance *ri;
2003 kprobe_opcode_t *ret;
2004
2005 if (WARN_ON_ONCE(!cur))
2006 return 0;
2007
2008 do {
2009 ret = __kretprobe_find_ret_addr(tsk, cur);
2010 if (!ret)
2011 break;
2012 ri = container_of(*cur, struct kretprobe_instance, llist);
2013 } while (ri->fp != fp);
2014
2015 return (unsigned long)ret;
2016}
2017NOKPROBE_SYMBOL(kretprobe_find_ret_addr);
2018
2019void __weak arch_kretprobe_fixup_return(struct pt_regs *regs,
2020 kprobe_opcode_t *correct_ret_addr)
2021{
2022 /*
2023 * Do nothing by default. Please fill this to update the fake return
2024 * address on the stack with the correct one on each arch if possible.
2025 */
2026}
2027
2028unsigned long __kretprobe_trampoline_handler(struct pt_regs *regs,
2029 void *frame_pointer)
2030{
2031 struct kretprobe_instance *ri = NULL;
2032 struct llist_node *first, *node = NULL;
2033 kprobe_opcode_t *correct_ret_addr;
2034 struct kretprobe *rp;
2035
2036 /* Find correct address and all nodes for this frame. */
2037 correct_ret_addr = __kretprobe_find_ret_addr(current, &node);
2038 if (!correct_ret_addr) {
2039 pr_err("kretprobe: Return address not found, not execute handler. Maybe there is a bug in the kernel.\n");
2040 BUG_ON(1);
2041 }
2042
2043 /*
2044 * Set the return address as the instruction pointer, because if the
2045 * user handler calls stack_trace_save_regs() with this 'regs',
2046 * the stack trace will start from the instruction pointer.
2047 */
2048 instruction_pointer_set(regs, (unsigned long)correct_ret_addr);
2049
2050 /* Run the user handler of the nodes. */
2051 first = current->kretprobe_instances.first;
2052 while (first) {
2053 ri = container_of(first, struct kretprobe_instance, llist);
2054
2055 if (WARN_ON_ONCE(ri->fp != frame_pointer))
2056 break;
2057
2058 rp = get_kretprobe(ri);
2059 if (rp && rp->handler) {
2060 struct kprobe *prev = kprobe_running();
2061
2062 __this_cpu_write(current_kprobe, &rp->kp);
2063 ri->ret_addr = correct_ret_addr;
2064 rp->handler(ri, regs);
2065 __this_cpu_write(current_kprobe, prev);
2066 }
2067 if (first == node)
2068 break;
2069
2070 first = first->next;
2071 }
2072
2073 arch_kretprobe_fixup_return(regs, correct_ret_addr);
2074
2075 /* Unlink all nodes for this frame. */
2076 first = current->kretprobe_instances.first;
2077 current->kretprobe_instances.first = node->next;
2078 node->next = NULL;
2079
2080 /* Recycle free instances. */
2081 while (first) {
2082 ri = container_of(first, struct kretprobe_instance, llist);
2083 first = first->next;
2084
2085 recycle_rp_inst(ri);
2086 }
2087
2088 return (unsigned long)correct_ret_addr;
2089}
2090NOKPROBE_SYMBOL(__kretprobe_trampoline_handler)
2091
2092/*
2093 * This kprobe pre_handler is registered with every kretprobe. When probe
2094 * hits it will set up the return probe.
2095 */
2096static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
2097{
2098 struct kretprobe *rp = container_of(p, struct kretprobe, kp);
2099 struct kretprobe_holder *rph = rp->rph;
2100 struct kretprobe_instance *ri;
2101
2102 ri = objpool_pop(&rph->pool);
2103 if (!ri) {
2104 rp->nmissed++;
2105 return 0;
2106 }
2107
2108 if (rp->entry_handler && rp->entry_handler(ri, regs)) {
2109 objpool_push(ri, &rph->pool);
2110 return 0;
2111 }
2112
2113 arch_prepare_kretprobe(ri, regs);
2114
2115 __llist_add(&ri->llist, &current->kretprobe_instances);
2116
2117 return 0;
2118}
2119NOKPROBE_SYMBOL(pre_handler_kretprobe);
2120#else /* CONFIG_KRETPROBE_ON_RETHOOK */
2121/*
2122 * This kprobe pre_handler is registered with every kretprobe. When probe
2123 * hits it will set up the return probe.
2124 */
2125static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
2126{
2127 struct kretprobe *rp = container_of(p, struct kretprobe, kp);
2128 struct kretprobe_instance *ri;
2129 struct rethook_node *rhn;
2130
2131 rhn = rethook_try_get(rh: rp->rh);
2132 if (!rhn) {
2133 rp->nmissed++;
2134 return 0;
2135 }
2136
2137 ri = container_of(rhn, struct kretprobe_instance, node);
2138
2139 if (rp->entry_handler && rp->entry_handler(ri, regs))
2140 rethook_recycle(node: rhn);
2141 else
2142 rethook_hook(node: rhn, regs, mcount: kprobe_ftrace(p));
2143
2144 return 0;
2145}
2146NOKPROBE_SYMBOL(pre_handler_kretprobe);
2147
2148static void kretprobe_rethook_handler(struct rethook_node *rh, void *data,
2149 unsigned long ret_addr,
2150 struct pt_regs *regs)
2151{
2152 struct kretprobe *rp = (struct kretprobe *)data;
2153 struct kretprobe_instance *ri;
2154 struct kprobe_ctlblk *kcb;
2155
2156 /* The data must NOT be null. This means rethook data structure is broken. */
2157 if (WARN_ON_ONCE(!data) || !rp->handler)
2158 return;
2159
2160 __this_cpu_write(current_kprobe, &rp->kp);
2161 kcb = get_kprobe_ctlblk();
2162 kcb->kprobe_status = KPROBE_HIT_ACTIVE;
2163
2164 ri = container_of(rh, struct kretprobe_instance, node);
2165 rp->handler(ri, regs);
2166
2167 __this_cpu_write(current_kprobe, NULL);
2168}
2169NOKPROBE_SYMBOL(kretprobe_rethook_handler);
2170
2171#endif /* !CONFIG_KRETPROBE_ON_RETHOOK */
2172
2173/**
2174 * kprobe_on_func_entry() -- check whether given address is function entry
2175 * @addr: Target address
2176 * @sym: Target symbol name
2177 * @offset: The offset from the symbol or the address
2178 *
2179 * This checks whether the given @addr+@offset or @sym+@offset is on the
2180 * function entry address or not.
2181 * This returns 0 if it is the function entry, or -EINVAL if it is not.
2182 * And also it returns -ENOENT if it fails the symbol or address lookup.
2183 * Caller must pass @addr or @sym (either one must be NULL), or this
2184 * returns -EINVAL.
2185 */
2186int kprobe_on_func_entry(kprobe_opcode_t *addr, const char *sym, unsigned long offset)
2187{
2188 bool on_func_entry;
2189 kprobe_opcode_t *kp_addr = _kprobe_addr(addr, symbol_name: sym, offset, on_func_entry: &on_func_entry);
2190
2191 if (IS_ERR(ptr: kp_addr))
2192 return PTR_ERR(ptr: kp_addr);
2193
2194 if (!on_func_entry)
2195 return -EINVAL;
2196
2197 return 0;
2198}
2199
2200int register_kretprobe(struct kretprobe *rp)
2201{
2202 int ret;
2203 int i;
2204 void *addr;
2205
2206 ret = kprobe_on_func_entry(addr: rp->kp.addr, sym: rp->kp.symbol_name, offset: rp->kp.offset);
2207 if (ret)
2208 return ret;
2209
2210 /* If only 'rp->kp.addr' is specified, check reregistering kprobes */
2211 if (rp->kp.addr && warn_kprobe_rereg(p: &rp->kp))
2212 return -EINVAL;
2213
2214 if (kretprobe_blacklist_size) {
2215 addr = kprobe_addr(p: &rp->kp);
2216 if (IS_ERR(ptr: addr))
2217 return PTR_ERR(ptr: addr);
2218
2219 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
2220 if (kretprobe_blacklist[i].addr == addr)
2221 return -EINVAL;
2222 }
2223 }
2224
2225 if (rp->data_size > KRETPROBE_MAX_DATA_SIZE)
2226 return -E2BIG;
2227
2228 rp->kp.pre_handler = pre_handler_kretprobe;
2229 rp->kp.post_handler = NULL;
2230
2231 /* Pre-allocate memory for max kretprobe instances */
2232 if (rp->maxactive <= 0)
2233 rp->maxactive = max_t(unsigned int, 10, 2*num_possible_cpus());
2234
2235#ifdef CONFIG_KRETPROBE_ON_RETHOOK
2236 rp->rh = rethook_alloc(data: (void *)rp, handler: kretprobe_rethook_handler,
2237 size: sizeof(struct kretprobe_instance) +
2238 rp->data_size, num: rp->maxactive);
2239 if (IS_ERR(ptr: rp->rh))
2240 return PTR_ERR(ptr: rp->rh);
2241
2242 rp->nmissed = 0;
2243 /* Establish function entry probe point */
2244 ret = register_kprobe(&rp->kp);
2245 if (ret != 0) {
2246 rethook_free(rh: rp->rh);
2247 rp->rh = NULL;
2248 }
2249#else /* !CONFIG_KRETPROBE_ON_RETHOOK */
2250 rp->rph = kzalloc(sizeof(struct kretprobe_holder), GFP_KERNEL);
2251 if (!rp->rph)
2252 return -ENOMEM;
2253
2254 if (objpool_init(&rp->rph->pool, rp->maxactive, rp->data_size +
2255 sizeof(struct kretprobe_instance), GFP_KERNEL,
2256 rp->rph, kretprobe_init_inst, kretprobe_fini_pool)) {
2257 kfree(rp->rph);
2258 rp->rph = NULL;
2259 return -ENOMEM;
2260 }
2261 rcu_assign_pointer(rp->rph->rp, rp);
2262 rp->nmissed = 0;
2263 /* Establish function entry probe point */
2264 ret = register_kprobe(&rp->kp);
2265 if (ret != 0)
2266 free_rp_inst(rp);
2267#endif
2268 return ret;
2269}
2270EXPORT_SYMBOL_GPL(register_kretprobe);
2271
2272int register_kretprobes(struct kretprobe **rps, int num)
2273{
2274 int ret = 0, i;
2275
2276 if (num <= 0)
2277 return -EINVAL;
2278 for (i = 0; i < num; i++) {
2279 ret = register_kretprobe(rps[i]);
2280 if (ret < 0) {
2281 if (i > 0)
2282 unregister_kretprobes(rps, num: i);
2283 break;
2284 }
2285 }
2286 return ret;
2287}
2288EXPORT_SYMBOL_GPL(register_kretprobes);
2289
2290void unregister_kretprobe(struct kretprobe *rp)
2291{
2292 unregister_kretprobes(rps: &rp, num: 1);
2293}
2294EXPORT_SYMBOL_GPL(unregister_kretprobe);
2295
2296void unregister_kretprobes(struct kretprobe **rps, int num)
2297{
2298 int i;
2299
2300 if (num <= 0)
2301 return;
2302 mutex_lock(&kprobe_mutex);
2303 for (i = 0; i < num; i++) {
2304 if (__unregister_kprobe_top(p: &rps[i]->kp) < 0)
2305 rps[i]->kp.addr = NULL;
2306#ifdef CONFIG_KRETPROBE_ON_RETHOOK
2307 rethook_free(rh: rps[i]->rh);
2308#else
2309 rcu_assign_pointer(rps[i]->rph->rp, NULL);
2310#endif
2311 }
2312 mutex_unlock(lock: &kprobe_mutex);
2313
2314 synchronize_rcu();
2315 for (i = 0; i < num; i++) {
2316 if (rps[i]->kp.addr) {
2317 __unregister_kprobe_bottom(p: &rps[i]->kp);
2318#ifndef CONFIG_KRETPROBE_ON_RETHOOK
2319 free_rp_inst(rps[i]);
2320#endif
2321 }
2322 }
2323}
2324EXPORT_SYMBOL_GPL(unregister_kretprobes);
2325
2326#else /* CONFIG_KRETPROBES */
2327int register_kretprobe(struct kretprobe *rp)
2328{
2329 return -EOPNOTSUPP;
2330}
2331EXPORT_SYMBOL_GPL(register_kretprobe);
2332
2333int register_kretprobes(struct kretprobe **rps, int num)
2334{
2335 return -EOPNOTSUPP;
2336}
2337EXPORT_SYMBOL_GPL(register_kretprobes);
2338
2339void unregister_kretprobe(struct kretprobe *rp)
2340{
2341}
2342EXPORT_SYMBOL_GPL(unregister_kretprobe);
2343
2344void unregister_kretprobes(struct kretprobe **rps, int num)
2345{
2346}
2347EXPORT_SYMBOL_GPL(unregister_kretprobes);
2348
2349static int pre_handler_kretprobe(struct kprobe *p, struct pt_regs *regs)
2350{
2351 return 0;
2352}
2353NOKPROBE_SYMBOL(pre_handler_kretprobe);
2354
2355#endif /* CONFIG_KRETPROBES */
2356
2357/* Set the kprobe gone and remove its instruction buffer. */
2358static void kill_kprobe(struct kprobe *p)
2359{
2360 struct kprobe *kp;
2361
2362 lockdep_assert_held(&kprobe_mutex);
2363
2364 /*
2365 * The module is going away. We should disarm the kprobe which
2366 * is using ftrace, because ftrace framework is still available at
2367 * 'MODULE_STATE_GOING' notification.
2368 */
2369 if (kprobe_ftrace(p) && !kprobe_disabled(p) && !kprobes_all_disarmed)
2370 disarm_kprobe_ftrace(p);
2371
2372 p->flags |= KPROBE_FLAG_GONE;
2373 if (kprobe_aggrprobe(p)) {
2374 /*
2375 * If this is an aggr_kprobe, we have to list all the
2376 * chained probes and mark them GONE.
2377 */
2378 list_for_each_entry(kp, &p->list, list)
2379 kp->flags |= KPROBE_FLAG_GONE;
2380 p->post_handler = NULL;
2381 kill_optimized_kprobe(p);
2382 }
2383 /*
2384 * Here, we can remove insn_slot safely, because no thread calls
2385 * the original probed function (which will be freed soon) any more.
2386 */
2387 arch_remove_kprobe(p);
2388}
2389
2390/* Disable one kprobe */
2391int disable_kprobe(struct kprobe *kp)
2392{
2393 int ret = 0;
2394 struct kprobe *p;
2395
2396 mutex_lock(&kprobe_mutex);
2397
2398 /* Disable this kprobe */
2399 p = __disable_kprobe(p: kp);
2400 if (IS_ERR(ptr: p))
2401 ret = PTR_ERR(ptr: p);
2402
2403 mutex_unlock(lock: &kprobe_mutex);
2404 return ret;
2405}
2406EXPORT_SYMBOL_GPL(disable_kprobe);
2407
2408/* Enable one kprobe */
2409int enable_kprobe(struct kprobe *kp)
2410{
2411 int ret = 0;
2412 struct kprobe *p;
2413
2414 mutex_lock(&kprobe_mutex);
2415
2416 /* Check whether specified probe is valid. */
2417 p = __get_valid_kprobe(p: kp);
2418 if (unlikely(p == NULL)) {
2419 ret = -EINVAL;
2420 goto out;
2421 }
2422
2423 if (kprobe_gone(p: kp)) {
2424 /* This kprobe has gone, we couldn't enable it. */
2425 ret = -EINVAL;
2426 goto out;
2427 }
2428
2429 if (p != kp)
2430 kp->flags &= ~KPROBE_FLAG_DISABLED;
2431
2432 if (!kprobes_all_disarmed && kprobe_disabled(p)) {
2433 p->flags &= ~KPROBE_FLAG_DISABLED;
2434 ret = arm_kprobe(kp: p);
2435 if (ret) {
2436 p->flags |= KPROBE_FLAG_DISABLED;
2437 if (p != kp)
2438 kp->flags |= KPROBE_FLAG_DISABLED;
2439 }
2440 }
2441out:
2442 mutex_unlock(lock: &kprobe_mutex);
2443 return ret;
2444}
2445EXPORT_SYMBOL_GPL(enable_kprobe);
2446
2447/* Caller must NOT call this in usual path. This is only for critical case */
2448void dump_kprobe(struct kprobe *kp)
2449{
2450 pr_err("Dump kprobe:\n.symbol_name = %s, .offset = %x, .addr = %pS\n",
2451 kp->symbol_name, kp->offset, kp->addr);
2452}
2453NOKPROBE_SYMBOL(dump_kprobe);
2454
2455int kprobe_add_ksym_blacklist(unsigned long entry)
2456{
2457 struct kprobe_blacklist_entry *ent;
2458 unsigned long offset = 0, size = 0;
2459
2460 if (!kernel_text_address(addr: entry) ||
2461 !kallsyms_lookup_size_offset(addr: entry, symbolsize: &size, offset: &offset))
2462 return -EINVAL;
2463
2464 ent = kmalloc(size: sizeof(*ent), GFP_KERNEL);
2465 if (!ent)
2466 return -ENOMEM;
2467 ent->start_addr = entry;
2468 ent->end_addr = entry + size;
2469 INIT_LIST_HEAD(list: &ent->list);
2470 list_add_tail(new: &ent->list, head: &kprobe_blacklist);
2471
2472 return (int)size;
2473}
2474
2475/* Add all symbols in given area into kprobe blacklist */
2476int kprobe_add_area_blacklist(unsigned long start, unsigned long end)
2477{
2478 unsigned long entry;
2479 int ret = 0;
2480
2481 for (entry = start; entry < end; entry += ret) {
2482 ret = kprobe_add_ksym_blacklist(entry);
2483 if (ret < 0)
2484 return ret;
2485 if (ret == 0) /* In case of alias symbol */
2486 ret = 1;
2487 }
2488 return 0;
2489}
2490
2491/* Remove all symbols in given area from kprobe blacklist */
2492static void kprobe_remove_area_blacklist(unsigned long start, unsigned long end)
2493{
2494 struct kprobe_blacklist_entry *ent, *n;
2495
2496 list_for_each_entry_safe(ent, n, &kprobe_blacklist, list) {
2497 if (ent->start_addr < start || ent->start_addr >= end)
2498 continue;
2499 list_del(entry: &ent->list);
2500 kfree(objp: ent);
2501 }
2502}
2503
2504static void kprobe_remove_ksym_blacklist(unsigned long entry)
2505{
2506 kprobe_remove_area_blacklist(start: entry, end: entry + 1);
2507}
2508
2509int __weak arch_kprobe_get_kallsym(unsigned int *symnum, unsigned long *value,
2510 char *type, char *sym)
2511{
2512 return -ERANGE;
2513}
2514
2515int kprobe_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
2516 char *sym)
2517{
2518#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
2519 if (!kprobe_cache_get_kallsym(c: &kprobe_insn_slots, symnum: &symnum, value, type, sym))
2520 return 0;
2521#ifdef CONFIG_OPTPROBES
2522 if (!kprobe_cache_get_kallsym(c: &kprobe_optinsn_slots, symnum: &symnum, value, type, sym))
2523 return 0;
2524#endif
2525#endif
2526 if (!arch_kprobe_get_kallsym(symnum: &symnum, value, type, sym))
2527 return 0;
2528 return -ERANGE;
2529}
2530
2531int __init __weak arch_populate_kprobe_blacklist(void)
2532{
2533 return 0;
2534}
2535
2536/*
2537 * Lookup and populate the kprobe_blacklist.
2538 *
2539 * Unlike the kretprobe blacklist, we'll need to determine
2540 * the range of addresses that belong to the said functions,
2541 * since a kprobe need not necessarily be at the beginning
2542 * of a function.
2543 */
2544static int __init populate_kprobe_blacklist(unsigned long *start,
2545 unsigned long *end)
2546{
2547 unsigned long entry;
2548 unsigned long *iter;
2549 int ret;
2550
2551 for (iter = start; iter < end; iter++) {
2552 entry = (unsigned long)dereference_symbol_descriptor(ptr: (void *)*iter);
2553 ret = kprobe_add_ksym_blacklist(entry);
2554 if (ret == -EINVAL)
2555 continue;
2556 if (ret < 0)
2557 return ret;
2558 }
2559
2560 /* Symbols in '__kprobes_text' are blacklisted */
2561 ret = kprobe_add_area_blacklist(start: (unsigned long)__kprobes_text_start,
2562 end: (unsigned long)__kprobes_text_end);
2563 if (ret)
2564 return ret;
2565
2566 /* Symbols in 'noinstr' section are blacklisted */
2567 ret = kprobe_add_area_blacklist(start: (unsigned long)__noinstr_text_start,
2568 end: (unsigned long)__noinstr_text_end);
2569
2570 return ret ? : arch_populate_kprobe_blacklist();
2571}
2572
2573static void add_module_kprobe_blacklist(struct module *mod)
2574{
2575 unsigned long start, end;
2576 int i;
2577
2578 if (mod->kprobe_blacklist) {
2579 for (i = 0; i < mod->num_kprobe_blacklist; i++)
2580 kprobe_add_ksym_blacklist(entry: mod->kprobe_blacklist[i]);
2581 }
2582
2583 start = (unsigned long)mod->kprobes_text_start;
2584 if (start) {
2585 end = start + mod->kprobes_text_size;
2586 kprobe_add_area_blacklist(start, end);
2587 }
2588
2589 start = (unsigned long)mod->noinstr_text_start;
2590 if (start) {
2591 end = start + mod->noinstr_text_size;
2592 kprobe_add_area_blacklist(start, end);
2593 }
2594}
2595
2596static void remove_module_kprobe_blacklist(struct module *mod)
2597{
2598 unsigned long start, end;
2599 int i;
2600
2601 if (mod->kprobe_blacklist) {
2602 for (i = 0; i < mod->num_kprobe_blacklist; i++)
2603 kprobe_remove_ksym_blacklist(entry: mod->kprobe_blacklist[i]);
2604 }
2605
2606 start = (unsigned long)mod->kprobes_text_start;
2607 if (start) {
2608 end = start + mod->kprobes_text_size;
2609 kprobe_remove_area_blacklist(start, end);
2610 }
2611
2612 start = (unsigned long)mod->noinstr_text_start;
2613 if (start) {
2614 end = start + mod->noinstr_text_size;
2615 kprobe_remove_area_blacklist(start, end);
2616 }
2617}
2618
2619/* Module notifier call back, checking kprobes on the module */
2620static int kprobes_module_callback(struct notifier_block *nb,
2621 unsigned long val, void *data)
2622{
2623 struct module *mod = data;
2624 struct hlist_head *head;
2625 struct kprobe *p;
2626 unsigned int i;
2627 int checkcore = (val == MODULE_STATE_GOING);
2628
2629 if (val == MODULE_STATE_COMING) {
2630 mutex_lock(&kprobe_mutex);
2631 add_module_kprobe_blacklist(mod);
2632 mutex_unlock(lock: &kprobe_mutex);
2633 }
2634 if (val != MODULE_STATE_GOING && val != MODULE_STATE_LIVE)
2635 return NOTIFY_DONE;
2636
2637 /*
2638 * When 'MODULE_STATE_GOING' was notified, both of module '.text' and
2639 * '.init.text' sections would be freed. When 'MODULE_STATE_LIVE' was
2640 * notified, only '.init.text' section would be freed. We need to
2641 * disable kprobes which have been inserted in the sections.
2642 */
2643 mutex_lock(&kprobe_mutex);
2644 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2645 head = &kprobe_table[i];
2646 hlist_for_each_entry(p, head, hlist)
2647 if (within_module_init(addr: (unsigned long)p->addr, mod) ||
2648 (checkcore &&
2649 within_module_core(addr: (unsigned long)p->addr, mod))) {
2650 /*
2651 * The vaddr this probe is installed will soon
2652 * be vfreed buy not synced to disk. Hence,
2653 * disarming the breakpoint isn't needed.
2654 *
2655 * Note, this will also move any optimized probes
2656 * that are pending to be removed from their
2657 * corresponding lists to the 'freeing_list' and
2658 * will not be touched by the delayed
2659 * kprobe_optimizer() work handler.
2660 */
2661 kill_kprobe(p);
2662 }
2663 }
2664 if (val == MODULE_STATE_GOING)
2665 remove_module_kprobe_blacklist(mod);
2666 mutex_unlock(lock: &kprobe_mutex);
2667 return NOTIFY_DONE;
2668}
2669
2670static struct notifier_block kprobe_module_nb = {
2671 .notifier_call = kprobes_module_callback,
2672 .priority = 0
2673};
2674
2675void kprobe_free_init_mem(void)
2676{
2677 void *start = (void *)(&__init_begin);
2678 void *end = (void *)(&__init_end);
2679 struct hlist_head *head;
2680 struct kprobe *p;
2681 int i;
2682
2683 mutex_lock(&kprobe_mutex);
2684
2685 /* Kill all kprobes on initmem because the target code has been freed. */
2686 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2687 head = &kprobe_table[i];
2688 hlist_for_each_entry(p, head, hlist) {
2689 if (start <= (void *)p->addr && (void *)p->addr < end)
2690 kill_kprobe(p);
2691 }
2692 }
2693
2694 mutex_unlock(lock: &kprobe_mutex);
2695}
2696
2697static int __init init_kprobes(void)
2698{
2699 int i, err;
2700
2701 /* FIXME allocate the probe table, currently defined statically */
2702 /* initialize all list heads */
2703 for (i = 0; i < KPROBE_TABLE_SIZE; i++)
2704 INIT_HLIST_HEAD(&kprobe_table[i]);
2705
2706 err = populate_kprobe_blacklist(start: __start_kprobe_blacklist,
2707 end: __stop_kprobe_blacklist);
2708 if (err)
2709 pr_err("Failed to populate blacklist (error %d), kprobes not restricted, be careful using them!\n", err);
2710
2711 if (kretprobe_blacklist_size) {
2712 /* lookup the function address from its name */
2713 for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
2714 kretprobe_blacklist[i].addr =
2715 kprobe_lookup_name(name: kretprobe_blacklist[i].name, unused: 0);
2716 if (!kretprobe_blacklist[i].addr)
2717 pr_err("Failed to lookup symbol '%s' for kretprobe blacklist. Maybe the target function is removed or renamed.\n",
2718 kretprobe_blacklist[i].name);
2719 }
2720 }
2721
2722 /* By default, kprobes are armed */
2723 kprobes_all_disarmed = false;
2724
2725#if defined(CONFIG_OPTPROBES) && defined(__ARCH_WANT_KPROBES_INSN_SLOT)
2726 /* Init 'kprobe_optinsn_slots' for allocation */
2727 kprobe_optinsn_slots.insn_size = MAX_OPTINSN_SIZE;
2728#endif
2729
2730 err = arch_init_kprobes();
2731 if (!err)
2732 err = register_die_notifier(nb: &kprobe_exceptions_nb);
2733 if (!err)
2734 err = register_module_notifier(nb: &kprobe_module_nb);
2735
2736 kprobes_initialized = (err == 0);
2737 kprobe_sysctls_init();
2738 return err;
2739}
2740early_initcall(init_kprobes);
2741
2742#if defined(CONFIG_OPTPROBES)
2743static int __init init_optprobes(void)
2744{
2745 /*
2746 * Enable kprobe optimization - this kicks the optimizer which
2747 * depends on synchronize_rcu_tasks() and ksoftirqd, that is
2748 * not spawned in early initcall. So delay the optimization.
2749 */
2750 optimize_all_kprobes();
2751
2752 return 0;
2753}
2754subsys_initcall(init_optprobes);
2755#endif
2756
2757#ifdef CONFIG_DEBUG_FS
2758static void report_probe(struct seq_file *pi, struct kprobe *p,
2759 const char *sym, int offset, char *modname, struct kprobe *pp)
2760{
2761 char *kprobe_type;
2762 void *addr = p->addr;
2763
2764 if (p->pre_handler == pre_handler_kretprobe)
2765 kprobe_type = "r";
2766 else
2767 kprobe_type = "k";
2768
2769 if (!kallsyms_show_value(cred: pi->file->f_cred))
2770 addr = NULL;
2771
2772 if (sym)
2773 seq_printf(m: pi, fmt: "%px %s %s+0x%x %s ",
2774 addr, kprobe_type, sym, offset,
2775 (modname ? modname : " "));
2776 else /* try to use %pS */
2777 seq_printf(m: pi, fmt: "%px %s %pS ",
2778 addr, kprobe_type, p->addr);
2779
2780 if (!pp)
2781 pp = p;
2782 seq_printf(m: pi, fmt: "%s%s%s%s\n",
2783 (kprobe_gone(p) ? "[GONE]" : ""),
2784 ((kprobe_disabled(p) && !kprobe_gone(p)) ? "[DISABLED]" : ""),
2785 (kprobe_optimized(p: pp) ? "[OPTIMIZED]" : ""),
2786 (kprobe_ftrace(p: pp) ? "[FTRACE]" : ""));
2787}
2788
2789static void *kprobe_seq_start(struct seq_file *f, loff_t *pos)
2790{
2791 return (*pos < KPROBE_TABLE_SIZE) ? pos : NULL;
2792}
2793
2794static void *kprobe_seq_next(struct seq_file *f, void *v, loff_t *pos)
2795{
2796 (*pos)++;
2797 if (*pos >= KPROBE_TABLE_SIZE)
2798 return NULL;
2799 return pos;
2800}
2801
2802static void kprobe_seq_stop(struct seq_file *f, void *v)
2803{
2804 /* Nothing to do */
2805}
2806
2807static int show_kprobe_addr(struct seq_file *pi, void *v)
2808{
2809 struct hlist_head *head;
2810 struct kprobe *p, *kp;
2811 const char *sym;
2812 unsigned int i = *(loff_t *) v;
2813 unsigned long offset = 0;
2814 char *modname, namebuf[KSYM_NAME_LEN];
2815
2816 head = &kprobe_table[i];
2817 preempt_disable();
2818 hlist_for_each_entry_rcu(p, head, hlist) {
2819 sym = kallsyms_lookup(addr: (unsigned long)p->addr, NULL,
2820 offset: &offset, modname: &modname, namebuf);
2821 if (kprobe_aggrprobe(p)) {
2822 list_for_each_entry_rcu(kp, &p->list, list)
2823 report_probe(pi, p: kp, sym, offset, modname, pp: p);
2824 } else
2825 report_probe(pi, p, sym, offset, modname, NULL);
2826 }
2827 preempt_enable();
2828 return 0;
2829}
2830
2831static const struct seq_operations kprobes_sops = {
2832 .start = kprobe_seq_start,
2833 .next = kprobe_seq_next,
2834 .stop = kprobe_seq_stop,
2835 .show = show_kprobe_addr
2836};
2837
2838DEFINE_SEQ_ATTRIBUTE(kprobes);
2839
2840/* kprobes/blacklist -- shows which functions can not be probed */
2841static void *kprobe_blacklist_seq_start(struct seq_file *m, loff_t *pos)
2842{
2843 mutex_lock(&kprobe_mutex);
2844 return seq_list_start(head: &kprobe_blacklist, pos: *pos);
2845}
2846
2847static void *kprobe_blacklist_seq_next(struct seq_file *m, void *v, loff_t *pos)
2848{
2849 return seq_list_next(v, head: &kprobe_blacklist, ppos: pos);
2850}
2851
2852static int kprobe_blacklist_seq_show(struct seq_file *m, void *v)
2853{
2854 struct kprobe_blacklist_entry *ent =
2855 list_entry(v, struct kprobe_blacklist_entry, list);
2856
2857 /*
2858 * If '/proc/kallsyms' is not showing kernel address, we won't
2859 * show them here either.
2860 */
2861 if (!kallsyms_show_value(cred: m->file->f_cred))
2862 seq_printf(m, fmt: "0x%px-0x%px\t%ps\n", NULL, NULL,
2863 (void *)ent->start_addr);
2864 else
2865 seq_printf(m, fmt: "0x%px-0x%px\t%ps\n", (void *)ent->start_addr,
2866 (void *)ent->end_addr, (void *)ent->start_addr);
2867 return 0;
2868}
2869
2870static void kprobe_blacklist_seq_stop(struct seq_file *f, void *v)
2871{
2872 mutex_unlock(lock: &kprobe_mutex);
2873}
2874
2875static const struct seq_operations kprobe_blacklist_sops = {
2876 .start = kprobe_blacklist_seq_start,
2877 .next = kprobe_blacklist_seq_next,
2878 .stop = kprobe_blacklist_seq_stop,
2879 .show = kprobe_blacklist_seq_show,
2880};
2881DEFINE_SEQ_ATTRIBUTE(kprobe_blacklist);
2882
2883static int arm_all_kprobes(void)
2884{
2885 struct hlist_head *head;
2886 struct kprobe *p;
2887 unsigned int i, total = 0, errors = 0;
2888 int err, ret = 0;
2889
2890 mutex_lock(&kprobe_mutex);
2891
2892 /* If kprobes are armed, just return */
2893 if (!kprobes_all_disarmed)
2894 goto already_enabled;
2895
2896 /*
2897 * optimize_kprobe() called by arm_kprobe() checks
2898 * kprobes_all_disarmed, so set kprobes_all_disarmed before
2899 * arm_kprobe.
2900 */
2901 kprobes_all_disarmed = false;
2902 /* Arming kprobes doesn't optimize kprobe itself */
2903 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2904 head = &kprobe_table[i];
2905 /* Arm all kprobes on a best-effort basis */
2906 hlist_for_each_entry(p, head, hlist) {
2907 if (!kprobe_disabled(p)) {
2908 err = arm_kprobe(kp: p);
2909 if (err) {
2910 errors++;
2911 ret = err;
2912 }
2913 total++;
2914 }
2915 }
2916 }
2917
2918 if (errors)
2919 pr_warn("Kprobes globally enabled, but failed to enable %d out of %d probes. Please check which kprobes are kept disabled via debugfs.\n",
2920 errors, total);
2921 else
2922 pr_info("Kprobes globally enabled\n");
2923
2924already_enabled:
2925 mutex_unlock(lock: &kprobe_mutex);
2926 return ret;
2927}
2928
2929static int disarm_all_kprobes(void)
2930{
2931 struct hlist_head *head;
2932 struct kprobe *p;
2933 unsigned int i, total = 0, errors = 0;
2934 int err, ret = 0;
2935
2936 mutex_lock(&kprobe_mutex);
2937
2938 /* If kprobes are already disarmed, just return */
2939 if (kprobes_all_disarmed) {
2940 mutex_unlock(lock: &kprobe_mutex);
2941 return 0;
2942 }
2943
2944 kprobes_all_disarmed = true;
2945
2946 for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
2947 head = &kprobe_table[i];
2948 /* Disarm all kprobes on a best-effort basis */
2949 hlist_for_each_entry(p, head, hlist) {
2950 if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) {
2951 err = disarm_kprobe(kp: p, reopt: false);
2952 if (err) {
2953 errors++;
2954 ret = err;
2955 }
2956 total++;
2957 }
2958 }
2959 }
2960
2961 if (errors)
2962 pr_warn("Kprobes globally disabled, but failed to disable %d out of %d probes. Please check which kprobes are kept enabled via debugfs.\n",
2963 errors, total);
2964 else
2965 pr_info("Kprobes globally disabled\n");
2966
2967 mutex_unlock(lock: &kprobe_mutex);
2968
2969 /* Wait for disarming all kprobes by optimizer */
2970 wait_for_kprobe_optimizer();
2971
2972 return ret;
2973}
2974
2975/*
2976 * XXX: The debugfs bool file interface doesn't allow for callbacks
2977 * when the bool state is switched. We can reuse that facility when
2978 * available
2979 */
2980static ssize_t read_enabled_file_bool(struct file *file,
2981 char __user *user_buf, size_t count, loff_t *ppos)
2982{
2983 char buf[3];
2984
2985 if (!kprobes_all_disarmed)
2986 buf[0] = '1';
2987 else
2988 buf[0] = '0';
2989 buf[1] = '\n';
2990 buf[2] = 0x00;
2991 return simple_read_from_buffer(to: user_buf, count, ppos, from: buf, available: 2);
2992}
2993
2994static ssize_t write_enabled_file_bool(struct file *file,
2995 const char __user *user_buf, size_t count, loff_t *ppos)
2996{
2997 bool enable;
2998 int ret;
2999
3000 ret = kstrtobool_from_user(s: user_buf, count, res: &enable);
3001 if (ret)
3002 return ret;
3003
3004 ret = enable ? arm_all_kprobes() : disarm_all_kprobes();
3005 if (ret)
3006 return ret;
3007
3008 return count;
3009}
3010
3011static const struct file_operations fops_kp = {
3012 .read = read_enabled_file_bool,
3013 .write = write_enabled_file_bool,
3014 .llseek = default_llseek,
3015};
3016
3017static int __init debugfs_kprobe_init(void)
3018{
3019 struct dentry *dir;
3020
3021 dir = debugfs_create_dir(name: "kprobes", NULL);
3022
3023 debugfs_create_file(name: "list", mode: 0400, parent: dir, NULL, fops: &kprobes_fops);
3024
3025 debugfs_create_file(name: "enabled", mode: 0600, parent: dir, NULL, fops: &fops_kp);
3026
3027 debugfs_create_file(name: "blacklist", mode: 0400, parent: dir, NULL,
3028 fops: &kprobe_blacklist_fops);
3029
3030 return 0;
3031}
3032
3033late_initcall(debugfs_kprobe_init);
3034#endif /* CONFIG_DEBUG_FS */
3035

source code of linux/kernel/kprobes.c