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25#include <linux/kernel.h>
26#include <linux/highmem.h>
27#include <linux/pagemap.h>
28#include <linux/slab.h>
29#include <linux/sched.h>
30#include <linux/rmap.h>
31#include <linux/mmu_notifier.h>
32#include <linux/swap.h>
33#include <linux/ptrace.h>
34#include <linux/kdebug.h>
35#include "../../mm/internal.h"
36#include <linux/percpu-rwsem.h>
37
38#include <linux/uprobes.h>
39
40#define UINSNS_PER_PAGE (PAGE_SIZE/UPROBE_XOL_SLOT_BYTES)
41#define MAX_UPROBE_XOL_SLOTS UINSNS_PER_PAGE
42
43static struct rb_root uprobes_tree = RB_ROOT;
44
45static DEFINE_SPINLOCK(uprobes_treelock);
46
47#define UPROBES_HASH_SZ 13
48
49
50
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59
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64
65
66
67static struct mutex uprobes_mutex[UPROBES_HASH_SZ];
68
69#define uprobes_hash(v) (&uprobes_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ])
70
71
72static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ];
73#define uprobes_mmap_hash(v) (&uprobes_mmap_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ])
74
75static struct percpu_rw_semaphore dup_mmap_sem;
76
77
78
79
80
81
82static atomic_t uprobe_events = ATOMIC_INIT(0);
83
84
85#define UPROBE_COPY_INSN 0
86
87#define UPROBE_RUN_HANDLER 1
88
89#define UPROBE_SKIP_SSTEP 2
90
91struct uprobe {
92 struct rb_node rb_node;
93 atomic_t ref;
94 struct rw_semaphore consumer_rwsem;
95 struct mutex copy_mutex;
96 struct list_head pending_list;
97 struct uprobe_consumer *consumers;
98 struct inode *inode;
99 loff_t offset;
100 unsigned long flags;
101 struct arch_uprobe arch;
102};
103
104
105
106
107
108
109
110
111
112static bool valid_vma(struct vm_area_struct *vma, bool is_register)
113{
114 vm_flags_t flags = VM_HUGETLB | VM_MAYEXEC | VM_SHARED;
115
116 if (is_register)
117 flags |= VM_WRITE;
118
119 return vma->vm_file && (vma->vm_flags & flags) == VM_MAYEXEC;
120}
121
122static unsigned long offset_to_vaddr(struct vm_area_struct *vma, loff_t offset)
123{
124 return vma->vm_start + offset - ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
125}
126
127static loff_t vaddr_to_offset(struct vm_area_struct *vma, unsigned long vaddr)
128{
129 return ((loff_t)vma->vm_pgoff << PAGE_SHIFT) + (vaddr - vma->vm_start);
130}
131
132
133
134
135
136
137
138
139
140
141
142
143static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
144 struct page *page, struct page *kpage)
145{
146 struct mm_struct *mm = vma->vm_mm;
147 spinlock_t *ptl;
148 pte_t *ptep;
149 int err;
150
151 const unsigned long mmun_start = addr;
152 const unsigned long mmun_end = addr + PAGE_SIZE;
153
154
155 lock_page(page);
156
157 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
158 err = -EAGAIN;
159 ptep = page_check_address(page, mm, addr, &ptl, 0);
160 if (!ptep)
161 goto unlock;
162
163 get_page(kpage);
164 page_add_new_anon_rmap(kpage, vma, addr);
165
166 if (!PageAnon(page)) {
167 dec_mm_counter(mm, MM_FILEPAGES);
168 inc_mm_counter(mm, MM_ANONPAGES);
169 }
170
171 flush_cache_page(vma, addr, pte_pfn(*ptep));
172 ptep_clear_flush(vma, addr, ptep);
173 set_pte_at_notify(mm, addr, ptep, mk_pte(kpage, vma->vm_page_prot));
174
175 page_remove_rmap(page);
176 if (!page_mapped(page))
177 try_to_free_swap(page);
178 pte_unmap_unlock(ptep, ptl);
179
180 if (vma->vm_flags & VM_LOCKED)
181 munlock_vma_page(page);
182 put_page(page);
183
184 err = 0;
185 unlock:
186 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
187 unlock_page(page);
188 return err;
189}
190
191
192
193
194
195
196
197bool __weak is_swbp_insn(uprobe_opcode_t *insn)
198{
199 return *insn == UPROBE_SWBP_INSN;
200}
201
202static void copy_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *opcode)
203{
204 void *kaddr = kmap_atomic(page);
205 memcpy(opcode, kaddr + (vaddr & ~PAGE_MASK), UPROBE_SWBP_INSN_SIZE);
206 kunmap_atomic(kaddr);
207}
208
209static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode)
210{
211 uprobe_opcode_t old_opcode;
212 bool is_swbp;
213
214 copy_opcode(page, vaddr, &old_opcode);
215 is_swbp = is_swbp_insn(&old_opcode);
216
217 if (is_swbp_insn(new_opcode)) {
218 if (is_swbp)
219 return 0;
220 } else {
221 if (!is_swbp)
222 return 0;
223 }
224
225 return 1;
226}
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249
250static int write_opcode(struct mm_struct *mm, unsigned long vaddr,
251 uprobe_opcode_t opcode)
252{
253 struct page *old_page, *new_page;
254 void *vaddr_old, *vaddr_new;
255 struct vm_area_struct *vma;
256 int ret;
257
258retry:
259
260 ret = get_user_pages(NULL, mm, vaddr, 1, 0, 1, &old_page, &vma);
261 if (ret <= 0)
262 return ret;
263
264 ret = verify_opcode(old_page, vaddr, &opcode);
265 if (ret <= 0)
266 goto put_old;
267
268 ret = -ENOMEM;
269 new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr);
270 if (!new_page)
271 goto put_old;
272
273 __SetPageUptodate(new_page);
274
275
276 vaddr_old = kmap_atomic(old_page);
277 vaddr_new = kmap_atomic(new_page);
278
279 memcpy(vaddr_new, vaddr_old, PAGE_SIZE);
280 memcpy(vaddr_new + (vaddr & ~PAGE_MASK), &opcode, UPROBE_SWBP_INSN_SIZE);
281
282 kunmap_atomic(vaddr_new);
283 kunmap_atomic(vaddr_old);
284
285 ret = anon_vma_prepare(vma);
286 if (ret)
287 goto put_new;
288
289 ret = __replace_page(vma, vaddr, old_page, new_page);
290
291put_new:
292 page_cache_release(new_page);
293put_old:
294 put_page(old_page);
295
296 if (unlikely(ret == -EAGAIN))
297 goto retry;
298 return ret;
299}
300
301
302
303
304
305
306
307
308
309
310int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr)
311{
312 return write_opcode(mm, vaddr, UPROBE_SWBP_INSN);
313}
314
315
316
317
318
319
320
321
322
323
324int __weak
325set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr)
326{
327 return write_opcode(mm, vaddr, *(uprobe_opcode_t *)auprobe->insn);
328}
329
330static int match_uprobe(struct uprobe *l, struct uprobe *r)
331{
332 if (l->inode < r->inode)
333 return -1;
334
335 if (l->inode > r->inode)
336 return 1;
337
338 if (l->offset < r->offset)
339 return -1;
340
341 if (l->offset > r->offset)
342 return 1;
343
344 return 0;
345}
346
347static struct uprobe *__find_uprobe(struct inode *inode, loff_t offset)
348{
349 struct uprobe u = { .inode = inode, .offset = offset };
350 struct rb_node *n = uprobes_tree.rb_node;
351 struct uprobe *uprobe;
352 int match;
353
354 while (n) {
355 uprobe = rb_entry(n, struct uprobe, rb_node);
356 match = match_uprobe(&u, uprobe);
357 if (!match) {
358 atomic_inc(&uprobe->ref);
359 return uprobe;
360 }
361
362 if (match < 0)
363 n = n->rb_left;
364 else
365 n = n->rb_right;
366 }
367 return NULL;
368}
369
370
371
372
373
374static struct uprobe *find_uprobe(struct inode *inode, loff_t offset)
375{
376 struct uprobe *uprobe;
377
378 spin_lock(&uprobes_treelock);
379 uprobe = __find_uprobe(inode, offset);
380 spin_unlock(&uprobes_treelock);
381
382 return uprobe;
383}
384
385static struct uprobe *__insert_uprobe(struct uprobe *uprobe)
386{
387 struct rb_node **p = &uprobes_tree.rb_node;
388 struct rb_node *parent = NULL;
389 struct uprobe *u;
390 int match;
391
392 while (*p) {
393 parent = *p;
394 u = rb_entry(parent, struct uprobe, rb_node);
395 match = match_uprobe(uprobe, u);
396 if (!match) {
397 atomic_inc(&u->ref);
398 return u;
399 }
400
401 if (match < 0)
402 p = &parent->rb_left;
403 else
404 p = &parent->rb_right;
405
406 }
407
408 u = NULL;
409 rb_link_node(&uprobe->rb_node, parent, p);
410 rb_insert_color(&uprobe->rb_node, &uprobes_tree);
411
412 atomic_set(&uprobe->ref, 2);
413
414 return u;
415}
416
417
418
419
420
421
422
423
424
425static struct uprobe *insert_uprobe(struct uprobe *uprobe)
426{
427 struct uprobe *u;
428
429 spin_lock(&uprobes_treelock);
430 u = __insert_uprobe(uprobe);
431 spin_unlock(&uprobes_treelock);
432
433
434 __set_bit(UPROBE_SKIP_SSTEP, &uprobe->flags);
435
436 return u;
437}
438
439static void put_uprobe(struct uprobe *uprobe)
440{
441 if (atomic_dec_and_test(&uprobe->ref))
442 kfree(uprobe);
443}
444
445static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset)
446{
447 struct uprobe *uprobe, *cur_uprobe;
448
449 uprobe = kzalloc(sizeof(struct uprobe), GFP_KERNEL);
450 if (!uprobe)
451 return NULL;
452
453 uprobe->inode = igrab(inode);
454 uprobe->offset = offset;
455 init_rwsem(&uprobe->consumer_rwsem);
456 mutex_init(&uprobe->copy_mutex);
457
458
459 cur_uprobe = insert_uprobe(uprobe);
460
461
462 if (cur_uprobe) {
463 kfree(uprobe);
464 uprobe = cur_uprobe;
465 iput(inode);
466 } else {
467 atomic_inc(&uprobe_events);
468 }
469
470 return uprobe;
471}
472
473static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs)
474{
475 struct uprobe_consumer *uc;
476
477 if (!test_bit(UPROBE_RUN_HANDLER, &uprobe->flags))
478 return;
479
480 down_read(&uprobe->consumer_rwsem);
481 for (uc = uprobe->consumers; uc; uc = uc->next) {
482 if (!uc->filter || uc->filter(uc, current))
483 uc->handler(uc, regs);
484 }
485 up_read(&uprobe->consumer_rwsem);
486}
487
488
489static struct uprobe_consumer *
490consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc)
491{
492 down_write(&uprobe->consumer_rwsem);
493 uc->next = uprobe->consumers;
494 uprobe->consumers = uc;
495 up_write(&uprobe->consumer_rwsem);
496
497 return uc->next;
498}
499
500
501
502
503
504
505static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *uc)
506{
507 struct uprobe_consumer **con;
508 bool ret = false;
509
510 down_write(&uprobe->consumer_rwsem);
511 for (con = &uprobe->consumers; *con; con = &(*con)->next) {
512 if (*con == uc) {
513 *con = uc->next;
514 ret = true;
515 break;
516 }
517 }
518 up_write(&uprobe->consumer_rwsem);
519
520 return ret;
521}
522
523static int
524__copy_insn(struct address_space *mapping, struct file *filp, char *insn,
525 unsigned long nbytes, loff_t offset)
526{
527 struct page *page;
528 void *vaddr;
529 unsigned long off;
530 pgoff_t idx;
531
532 if (!filp)
533 return -EINVAL;
534
535 if (!mapping->a_ops->readpage)
536 return -EIO;
537
538 idx = offset >> PAGE_CACHE_SHIFT;
539 off = offset & ~PAGE_MASK;
540
541
542
543
544
545 page = read_mapping_page(mapping, idx, filp);
546 if (IS_ERR(page))
547 return PTR_ERR(page);
548
549 vaddr = kmap_atomic(page);
550 memcpy(insn, vaddr + off, nbytes);
551 kunmap_atomic(vaddr);
552 page_cache_release(page);
553
554 return 0;
555}
556
557static int copy_insn(struct uprobe *uprobe, struct file *filp)
558{
559 struct address_space *mapping;
560 unsigned long nbytes;
561 int bytes;
562
563 nbytes = PAGE_SIZE - (uprobe->offset & ~PAGE_MASK);
564 mapping = uprobe->inode->i_mapping;
565
566
567 if (uprobe->offset + MAX_UINSN_BYTES > uprobe->inode->i_size)
568 bytes = uprobe->inode->i_size - uprobe->offset;
569 else
570 bytes = MAX_UINSN_BYTES;
571
572
573 if (nbytes < bytes) {
574 int err = __copy_insn(mapping, filp, uprobe->arch.insn + nbytes,
575 bytes - nbytes, uprobe->offset + nbytes);
576 if (err)
577 return err;
578 bytes = nbytes;
579 }
580 return __copy_insn(mapping, filp, uprobe->arch.insn, bytes, uprobe->offset);
581}
582
583static int prepare_uprobe(struct uprobe *uprobe, struct file *file,
584 struct mm_struct *mm, unsigned long vaddr)
585{
586 int ret = 0;
587
588 if (test_bit(UPROBE_COPY_INSN, &uprobe->flags))
589 return ret;
590
591 mutex_lock(&uprobe->copy_mutex);
592 if (test_bit(UPROBE_COPY_INSN, &uprobe->flags))
593 goto out;
594
595 ret = copy_insn(uprobe, file);
596 if (ret)
597 goto out;
598
599 ret = -ENOTSUPP;
600 if (is_swbp_insn((uprobe_opcode_t *)uprobe->arch.insn))
601 goto out;
602
603 ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, vaddr);
604 if (ret)
605 goto out;
606
607
608 BUG_ON((uprobe->offset & ~PAGE_MASK) +
609 UPROBE_SWBP_INSN_SIZE > PAGE_SIZE);
610
611 smp_wmb();
612 set_bit(UPROBE_COPY_INSN, &uprobe->flags);
613
614 out:
615 mutex_unlock(&uprobe->copy_mutex);
616
617 return ret;
618}
619
620static int
621install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm,
622 struct vm_area_struct *vma, unsigned long vaddr)
623{
624 bool first_uprobe;
625 int ret;
626
627
628
629
630
631
632
633
634 if (!uprobe->consumers)
635 return 0;
636
637 ret = prepare_uprobe(uprobe, vma->vm_file, mm, vaddr);
638 if (ret)
639 return ret;
640
641
642
643
644
645 first_uprobe = !test_bit(MMF_HAS_UPROBES, &mm->flags);
646 if (first_uprobe)
647 set_bit(MMF_HAS_UPROBES, &mm->flags);
648
649 ret = set_swbp(&uprobe->arch, mm, vaddr);
650 if (!ret)
651 clear_bit(MMF_RECALC_UPROBES, &mm->flags);
652 else if (first_uprobe)
653 clear_bit(MMF_HAS_UPROBES, &mm->flags);
654
655 return ret;
656}
657
658static int
659remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, unsigned long vaddr)
660{
661
662 if (!test_bit(MMF_HAS_UPROBES, &mm->flags))
663 return 0;
664
665 set_bit(MMF_RECALC_UPROBES, &mm->flags);
666 return set_orig_insn(&uprobe->arch, mm, vaddr);
667}
668
669
670
671
672
673
674static void delete_uprobe(struct uprobe *uprobe)
675{
676 spin_lock(&uprobes_treelock);
677 rb_erase(&uprobe->rb_node, &uprobes_tree);
678 spin_unlock(&uprobes_treelock);
679 iput(uprobe->inode);
680 put_uprobe(uprobe);
681 atomic_dec(&uprobe_events);
682}
683
684struct map_info {
685 struct map_info *next;
686 struct mm_struct *mm;
687 unsigned long vaddr;
688};
689
690static inline struct map_info *free_map_info(struct map_info *info)
691{
692 struct map_info *next = info->next;
693 kfree(info);
694 return next;
695}
696
697static struct map_info *
698build_map_info(struct address_space *mapping, loff_t offset, bool is_register)
699{
700 unsigned long pgoff = offset >> PAGE_SHIFT;
701 struct vm_area_struct *vma;
702 struct map_info *curr = NULL;
703 struct map_info *prev = NULL;
704 struct map_info *info;
705 int more = 0;
706
707 again:
708 mutex_lock(&mapping->i_mmap_mutex);
709 vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
710 if (!valid_vma(vma, is_register))
711 continue;
712
713 if (!prev && !more) {
714
715
716
717
718 prev = kmalloc(sizeof(struct map_info),
719 GFP_NOWAIT | __GFP_NOMEMALLOC | __GFP_NOWARN);
720 if (prev)
721 prev->next = NULL;
722 }
723 if (!prev) {
724 more++;
725 continue;
726 }
727
728 if (!atomic_inc_not_zero(&vma->vm_mm->mm_users))
729 continue;
730
731 info = prev;
732 prev = prev->next;
733 info->next = curr;
734 curr = info;
735
736 info->mm = vma->vm_mm;
737 info->vaddr = offset_to_vaddr(vma, offset);
738 }
739 mutex_unlock(&mapping->i_mmap_mutex);
740
741 if (!more)
742 goto out;
743
744 prev = curr;
745 while (curr) {
746 mmput(curr->mm);
747 curr = curr->next;
748 }
749
750 do {
751 info = kmalloc(sizeof(struct map_info), GFP_KERNEL);
752 if (!info) {
753 curr = ERR_PTR(-ENOMEM);
754 goto out;
755 }
756 info->next = prev;
757 prev = info;
758 } while (--more);
759
760 goto again;
761 out:
762 while (prev)
763 prev = free_map_info(prev);
764 return curr;
765}
766
767static int register_for_each_vma(struct uprobe *uprobe, bool is_register)
768{
769 struct map_info *info;
770 int err = 0;
771
772 percpu_down_write(&dup_mmap_sem);
773 info = build_map_info(uprobe->inode->i_mapping,
774 uprobe->offset, is_register);
775 if (IS_ERR(info)) {
776 err = PTR_ERR(info);
777 goto out;
778 }
779
780 while (info) {
781 struct mm_struct *mm = info->mm;
782 struct vm_area_struct *vma;
783
784 if (err && is_register)
785 goto free;
786
787 down_write(&mm->mmap_sem);
788 vma = find_vma(mm, info->vaddr);
789 if (!vma || !valid_vma(vma, is_register) ||
790 vma->vm_file->f_mapping->host != uprobe->inode)
791 goto unlock;
792
793 if (vma->vm_start > info->vaddr ||
794 vaddr_to_offset(vma, info->vaddr) != uprobe->offset)
795 goto unlock;
796
797 if (is_register)
798 err = install_breakpoint(uprobe, mm, vma, info->vaddr);
799 else
800 err |= remove_breakpoint(uprobe, mm, info->vaddr);
801
802 unlock:
803 up_write(&mm->mmap_sem);
804 free:
805 mmput(mm);
806 info = free_map_info(info);
807 }
808 out:
809 percpu_up_write(&dup_mmap_sem);
810 return err;
811}
812
813static int __uprobe_register(struct uprobe *uprobe)
814{
815 return register_for_each_vma(uprobe, true);
816}
817
818static void __uprobe_unregister(struct uprobe *uprobe)
819{
820 if (!register_for_each_vma(uprobe, false))
821 delete_uprobe(uprobe);
822
823
824}
825
826
827
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834
835
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841
842
843int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
844{
845 struct uprobe *uprobe;
846 int ret;
847
848 if (!inode || !uc || uc->next)
849 return -EINVAL;
850
851 if (offset > i_size_read(inode))
852 return -EINVAL;
853
854 ret = 0;
855 mutex_lock(uprobes_hash(inode));
856 uprobe = alloc_uprobe(inode, offset);
857
858 if (!uprobe) {
859 ret = -ENOMEM;
860 } else if (!consumer_add(uprobe, uc)) {
861 ret = __uprobe_register(uprobe);
862 if (ret) {
863 uprobe->consumers = NULL;
864 __uprobe_unregister(uprobe);
865 } else {
866 set_bit(UPROBE_RUN_HANDLER, &uprobe->flags);
867 }
868 }
869
870 mutex_unlock(uprobes_hash(inode));
871 if (uprobe)
872 put_uprobe(uprobe);
873
874 return ret;
875}
876
877
878
879
880
881
882
883void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc)
884{
885 struct uprobe *uprobe;
886
887 if (!inode || !uc)
888 return;
889
890 uprobe = find_uprobe(inode, offset);
891 if (!uprobe)
892 return;
893
894 mutex_lock(uprobes_hash(inode));
895
896 if (consumer_del(uprobe, uc)) {
897 if (!uprobe->consumers) {
898 __uprobe_unregister(uprobe);
899 clear_bit(UPROBE_RUN_HANDLER, &uprobe->flags);
900 }
901 }
902
903 mutex_unlock(uprobes_hash(inode));
904 if (uprobe)
905 put_uprobe(uprobe);
906}
907
908static struct rb_node *
909find_node_in_range(struct inode *inode, loff_t min, loff_t max)
910{
911 struct rb_node *n = uprobes_tree.rb_node;
912
913 while (n) {
914 struct uprobe *u = rb_entry(n, struct uprobe, rb_node);
915
916 if (inode < u->inode) {
917 n = n->rb_left;
918 } else if (inode > u->inode) {
919 n = n->rb_right;
920 } else {
921 if (max < u->offset)
922 n = n->rb_left;
923 else if (min > u->offset)
924 n = n->rb_right;
925 else
926 break;
927 }
928 }
929
930 return n;
931}
932
933
934
935
936static void build_probe_list(struct inode *inode,
937 struct vm_area_struct *vma,
938 unsigned long start, unsigned long end,
939 struct list_head *head)
940{
941 loff_t min, max;
942 struct rb_node *n, *t;
943 struct uprobe *u;
944
945 INIT_LIST_HEAD(head);
946 min = vaddr_to_offset(vma, start);
947 max = min + (end - start) - 1;
948
949 spin_lock(&uprobes_treelock);
950 n = find_node_in_range(inode, min, max);
951 if (n) {
952 for (t = n; t; t = rb_prev(t)) {
953 u = rb_entry(t, struct uprobe, rb_node);
954 if (u->inode != inode || u->offset < min)
955 break;
956 list_add(&u->pending_list, head);
957 atomic_inc(&u->ref);
958 }
959 for (t = n; (t = rb_next(t)); ) {
960 u = rb_entry(t, struct uprobe, rb_node);
961 if (u->inode != inode || u->offset > max)
962 break;
963 list_add(&u->pending_list, head);
964 atomic_inc(&u->ref);
965 }
966 }
967 spin_unlock(&uprobes_treelock);
968}
969
970
971
972
973
974
975
976int uprobe_mmap(struct vm_area_struct *vma)
977{
978 struct list_head tmp_list;
979 struct uprobe *uprobe, *u;
980 struct inode *inode;
981
982 if (!atomic_read(&uprobe_events) || !valid_vma(vma, true))
983 return 0;
984
985 inode = vma->vm_file->f_mapping->host;
986 if (!inode)
987 return 0;
988
989 mutex_lock(uprobes_mmap_hash(inode));
990 build_probe_list(inode, vma, vma->vm_start, vma->vm_end, &tmp_list);
991
992 list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) {
993 if (!fatal_signal_pending(current)) {
994 unsigned long vaddr = offset_to_vaddr(vma, uprobe->offset);
995 install_breakpoint(uprobe, vma->vm_mm, vma, vaddr);
996 }
997 put_uprobe(uprobe);
998 }
999 mutex_unlock(uprobes_mmap_hash(inode));
1000
1001 return 0;
1002}
1003
1004static bool
1005vma_has_uprobes(struct vm_area_struct *vma, unsigned long start, unsigned long end)
1006{
1007 loff_t min, max;
1008 struct inode *inode;
1009 struct rb_node *n;
1010
1011 inode = vma->vm_file->f_mapping->host;
1012
1013 min = vaddr_to_offset(vma, start);
1014 max = min + (end - start) - 1;
1015
1016 spin_lock(&uprobes_treelock);
1017 n = find_node_in_range(inode, min, max);
1018 spin_unlock(&uprobes_treelock);
1019
1020 return !!n;
1021}
1022
1023
1024
1025
1026void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end)
1027{
1028 if (!atomic_read(&uprobe_events) || !valid_vma(vma, false))
1029 return;
1030
1031 if (!atomic_read(&vma->vm_mm->mm_users))
1032 return;
1033
1034 if (!test_bit(MMF_HAS_UPROBES, &vma->vm_mm->flags) ||
1035 test_bit(MMF_RECALC_UPROBES, &vma->vm_mm->flags))
1036 return;
1037
1038 if (vma_has_uprobes(vma, start, end))
1039 set_bit(MMF_RECALC_UPROBES, &vma->vm_mm->flags);
1040}
1041
1042
1043static int xol_add_vma(struct xol_area *area)
1044{
1045 struct mm_struct *mm;
1046 int ret;
1047
1048 area->page = alloc_page(GFP_HIGHUSER);
1049 if (!area->page)
1050 return -ENOMEM;
1051
1052 ret = -EALREADY;
1053 mm = current->mm;
1054
1055 down_write(&mm->mmap_sem);
1056 if (mm->uprobes_state.xol_area)
1057 goto fail;
1058
1059 ret = -ENOMEM;
1060
1061
1062 area->vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, PAGE_SIZE, 0, 0);
1063 if (area->vaddr & ~PAGE_MASK) {
1064 ret = area->vaddr;
1065 goto fail;
1066 }
1067
1068 ret = install_special_mapping(mm, area->vaddr, PAGE_SIZE,
1069 VM_EXEC|VM_MAYEXEC|VM_DONTCOPY|VM_IO, &area->page);
1070 if (ret)
1071 goto fail;
1072
1073 smp_wmb();
1074 mm->uprobes_state.xol_area = area;
1075 ret = 0;
1076
1077fail:
1078 up_write(&mm->mmap_sem);
1079 if (ret)
1080 __free_page(area->page);
1081
1082 return ret;
1083}
1084
1085static struct xol_area *get_xol_area(struct mm_struct *mm)
1086{
1087 struct xol_area *area;
1088
1089 area = mm->uprobes_state.xol_area;
1090 smp_read_barrier_depends();
1091
1092 return area;
1093}
1094
1095
1096
1097
1098
1099
1100
1101
1102static struct xol_area *xol_alloc_area(void)
1103{
1104 struct xol_area *area;
1105
1106 area = kzalloc(sizeof(*area), GFP_KERNEL);
1107 if (unlikely(!area))
1108 return NULL;
1109
1110 area->bitmap = kzalloc(BITS_TO_LONGS(UINSNS_PER_PAGE) * sizeof(long), GFP_KERNEL);
1111
1112 if (!area->bitmap)
1113 goto fail;
1114
1115 init_waitqueue_head(&area->wq);
1116 if (!xol_add_vma(area))
1117 return area;
1118
1119fail:
1120 kfree(area->bitmap);
1121 kfree(area);
1122
1123 return get_xol_area(current->mm);
1124}
1125
1126
1127
1128
1129void uprobe_clear_state(struct mm_struct *mm)
1130{
1131 struct xol_area *area = mm->uprobes_state.xol_area;
1132
1133 if (!area)
1134 return;
1135
1136 put_page(area->page);
1137 kfree(area->bitmap);
1138 kfree(area);
1139}
1140
1141void uprobe_start_dup_mmap(void)
1142{
1143 percpu_down_read(&dup_mmap_sem);
1144}
1145
1146void uprobe_end_dup_mmap(void)
1147{
1148 percpu_up_read(&dup_mmap_sem);
1149}
1150
1151void uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm)
1152{
1153 newmm->uprobes_state.xol_area = NULL;
1154
1155 if (test_bit(MMF_HAS_UPROBES, &oldmm->flags)) {
1156 set_bit(MMF_HAS_UPROBES, &newmm->flags);
1157
1158 set_bit(MMF_RECALC_UPROBES, &newmm->flags);
1159 }
1160}
1161
1162
1163
1164
1165static unsigned long xol_take_insn_slot(struct xol_area *area)
1166{
1167 unsigned long slot_addr;
1168 int slot_nr;
1169
1170 do {
1171 slot_nr = find_first_zero_bit(area->bitmap, UINSNS_PER_PAGE);
1172 if (slot_nr < UINSNS_PER_PAGE) {
1173 if (!test_and_set_bit(slot_nr, area->bitmap))
1174 break;
1175
1176 slot_nr = UINSNS_PER_PAGE;
1177 continue;
1178 }
1179 wait_event(area->wq, (atomic_read(&area->slot_count) < UINSNS_PER_PAGE));
1180 } while (slot_nr >= UINSNS_PER_PAGE);
1181
1182 slot_addr = area->vaddr + (slot_nr * UPROBE_XOL_SLOT_BYTES);
1183 atomic_inc(&area->slot_count);
1184
1185 return slot_addr;
1186}
1187
1188
1189
1190
1191
1192
1193static unsigned long xol_get_insn_slot(struct uprobe *uprobe, unsigned long slot_addr)
1194{
1195 struct xol_area *area;
1196 unsigned long offset;
1197 void *vaddr;
1198
1199 area = get_xol_area(current->mm);
1200 if (!area) {
1201 area = xol_alloc_area();
1202 if (!area)
1203 return 0;
1204 }
1205 current->utask->xol_vaddr = xol_take_insn_slot(area);
1206
1207
1208
1209
1210
1211 if (unlikely(!current->utask->xol_vaddr))
1212 return 0;
1213
1214 current->utask->vaddr = slot_addr;
1215 offset = current->utask->xol_vaddr & ~PAGE_MASK;
1216 vaddr = kmap_atomic(area->page);
1217 memcpy(vaddr + offset, uprobe->arch.insn, MAX_UINSN_BYTES);
1218 kunmap_atomic(vaddr);
1219
1220
1221
1222
1223 flush_dcache_page(area->page);
1224
1225 return current->utask->xol_vaddr;
1226}
1227
1228
1229
1230
1231
1232
1233static void xol_free_insn_slot(struct task_struct *tsk)
1234{
1235 struct xol_area *area;
1236 unsigned long vma_end;
1237 unsigned long slot_addr;
1238
1239 if (!tsk->mm || !tsk->mm->uprobes_state.xol_area || !tsk->utask)
1240 return;
1241
1242 slot_addr = tsk->utask->xol_vaddr;
1243
1244 if (unlikely(!slot_addr || IS_ERR_VALUE(slot_addr)))
1245 return;
1246
1247 area = tsk->mm->uprobes_state.xol_area;
1248 vma_end = area->vaddr + PAGE_SIZE;
1249 if (area->vaddr <= slot_addr && slot_addr < vma_end) {
1250 unsigned long offset;
1251 int slot_nr;
1252
1253 offset = slot_addr - area->vaddr;
1254 slot_nr = offset / UPROBE_XOL_SLOT_BYTES;
1255 if (slot_nr >= UINSNS_PER_PAGE)
1256 return;
1257
1258 clear_bit(slot_nr, area->bitmap);
1259 atomic_dec(&area->slot_count);
1260 if (waitqueue_active(&area->wq))
1261 wake_up(&area->wq);
1262
1263 tsk->utask->xol_vaddr = 0;
1264 }
1265}
1266
1267
1268
1269
1270
1271
1272
1273unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs)
1274{
1275 return instruction_pointer(regs) - UPROBE_SWBP_INSN_SIZE;
1276}
1277
1278
1279
1280
1281
1282void uprobe_free_utask(struct task_struct *t)
1283{
1284 struct uprobe_task *utask = t->utask;
1285
1286 if (!utask)
1287 return;
1288
1289 if (utask->active_uprobe)
1290 put_uprobe(utask->active_uprobe);
1291
1292 xol_free_insn_slot(t);
1293 kfree(utask);
1294 t->utask = NULL;
1295}
1296
1297
1298
1299
1300void uprobe_copy_process(struct task_struct *t)
1301{
1302 t->utask = NULL;
1303}
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313static struct uprobe_task *add_utask(void)
1314{
1315 struct uprobe_task *utask;
1316
1317 utask = kzalloc(sizeof *utask, GFP_KERNEL);
1318 if (unlikely(!utask))
1319 return NULL;
1320
1321 current->utask = utask;
1322 return utask;
1323}
1324
1325
1326static int
1327pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long vaddr)
1328{
1329 if (xol_get_insn_slot(uprobe, vaddr) && !arch_uprobe_pre_xol(&uprobe->arch, regs))
1330 return 0;
1331
1332 return -EFAULT;
1333}
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344bool uprobe_deny_signal(void)
1345{
1346 struct task_struct *t = current;
1347 struct uprobe_task *utask = t->utask;
1348
1349 if (likely(!utask || !utask->active_uprobe))
1350 return false;
1351
1352 WARN_ON_ONCE(utask->state != UTASK_SSTEP);
1353
1354 if (signal_pending(t)) {
1355 spin_lock_irq(&t->sighand->siglock);
1356 clear_tsk_thread_flag(t, TIF_SIGPENDING);
1357 spin_unlock_irq(&t->sighand->siglock);
1358
1359 if (__fatal_signal_pending(t) || arch_uprobe_xol_was_trapped(t)) {
1360 utask->state = UTASK_SSTEP_TRAPPED;
1361 set_tsk_thread_flag(t, TIF_UPROBE);
1362 set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
1363 }
1364 }
1365
1366 return true;
1367}
1368
1369
1370
1371
1372
1373static bool can_skip_sstep(struct uprobe *uprobe, struct pt_regs *regs)
1374{
1375 if (test_bit(UPROBE_SKIP_SSTEP, &uprobe->flags)) {
1376 if (arch_uprobe_skip_sstep(&uprobe->arch, regs))
1377 return true;
1378 clear_bit(UPROBE_SKIP_SSTEP, &uprobe->flags);
1379 }
1380 return false;
1381}
1382
1383static void mmf_recalc_uprobes(struct mm_struct *mm)
1384{
1385 struct vm_area_struct *vma;
1386
1387 for (vma = mm->mmap; vma; vma = vma->vm_next) {
1388 if (!valid_vma(vma, false))
1389 continue;
1390
1391
1392
1393
1394
1395 if (vma_has_uprobes(vma, vma->vm_start, vma->vm_end))
1396 return;
1397 }
1398
1399 clear_bit(MMF_HAS_UPROBES, &mm->flags);
1400}
1401
1402static int is_swbp_at_addr(struct mm_struct *mm, unsigned long vaddr)
1403{
1404 struct page *page;
1405 uprobe_opcode_t opcode;
1406 int result;
1407
1408 pagefault_disable();
1409 result = __copy_from_user_inatomic(&opcode, (void __user*)vaddr,
1410 sizeof(opcode));
1411 pagefault_enable();
1412
1413 if (likely(result == 0))
1414 goto out;
1415
1416 result = get_user_pages(NULL, mm, vaddr, 1, 0, 1, &page, NULL);
1417 if (result < 0)
1418 return result;
1419
1420 copy_opcode(page, vaddr, &opcode);
1421 put_page(page);
1422 out:
1423 return is_swbp_insn(&opcode);
1424}
1425
1426static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp)
1427{
1428 struct mm_struct *mm = current->mm;
1429 struct uprobe *uprobe = NULL;
1430 struct vm_area_struct *vma;
1431
1432 down_read(&mm->mmap_sem);
1433 vma = find_vma(mm, bp_vaddr);
1434 if (vma && vma->vm_start <= bp_vaddr) {
1435 if (valid_vma(vma, false)) {
1436 struct inode *inode = vma->vm_file->f_mapping->host;
1437 loff_t offset = vaddr_to_offset(vma, bp_vaddr);
1438
1439 uprobe = find_uprobe(inode, offset);
1440 }
1441
1442 if (!uprobe)
1443 *is_swbp = is_swbp_at_addr(mm, bp_vaddr);
1444 } else {
1445 *is_swbp = -EFAULT;
1446 }
1447
1448 if (!uprobe && test_and_clear_bit(MMF_RECALC_UPROBES, &mm->flags))
1449 mmf_recalc_uprobes(mm);
1450 up_read(&mm->mmap_sem);
1451
1452 return uprobe;
1453}
1454
1455
1456
1457
1458
1459static void handle_swbp(struct pt_regs *regs)
1460{
1461 struct uprobe_task *utask;
1462 struct uprobe *uprobe;
1463 unsigned long bp_vaddr;
1464 int uninitialized_var(is_swbp);
1465
1466 bp_vaddr = uprobe_get_swbp_addr(regs);
1467 uprobe = find_active_uprobe(bp_vaddr, &is_swbp);
1468
1469 if (!uprobe) {
1470 if (is_swbp > 0) {
1471
1472 send_sig(SIGTRAP, current, 0);
1473 } else {
1474
1475
1476
1477
1478
1479
1480
1481
1482 instruction_pointer_set(regs, bp_vaddr);
1483 }
1484 return;
1485 }
1486
1487
1488
1489
1490
1491 smp_rmb();
1492 if (unlikely(!test_bit(UPROBE_COPY_INSN, &uprobe->flags)))
1493 goto restart;
1494
1495 utask = current->utask;
1496 if (!utask) {
1497 utask = add_utask();
1498
1499 if (!utask)
1500 goto restart;
1501 }
1502
1503 handler_chain(uprobe, regs);
1504 if (can_skip_sstep(uprobe, regs))
1505 goto out;
1506
1507 if (!pre_ssout(uprobe, regs, bp_vaddr)) {
1508 utask->active_uprobe = uprobe;
1509 utask->state = UTASK_SSTEP;
1510 return;
1511 }
1512
1513restart:
1514
1515
1516
1517
1518 instruction_pointer_set(regs, bp_vaddr);
1519out:
1520 put_uprobe(uprobe);
1521}
1522
1523
1524
1525
1526
1527static void handle_singlestep(struct uprobe_task *utask, struct pt_regs *regs)
1528{
1529 struct uprobe *uprobe;
1530
1531 uprobe = utask->active_uprobe;
1532 if (utask->state == UTASK_SSTEP_ACK)
1533 arch_uprobe_post_xol(&uprobe->arch, regs);
1534 else if (utask->state == UTASK_SSTEP_TRAPPED)
1535 arch_uprobe_abort_xol(&uprobe->arch, regs);
1536 else
1537 WARN_ON_ONCE(1);
1538
1539 put_uprobe(uprobe);
1540 utask->active_uprobe = NULL;
1541 utask->state = UTASK_RUNNING;
1542 xol_free_insn_slot(current);
1543
1544 spin_lock_irq(¤t->sighand->siglock);
1545 recalc_sigpending();
1546 spin_unlock_irq(¤t->sighand->siglock);
1547}
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560void uprobe_notify_resume(struct pt_regs *regs)
1561{
1562 struct uprobe_task *utask;
1563
1564 clear_thread_flag(TIF_UPROBE);
1565
1566 utask = current->utask;
1567 if (utask && utask->active_uprobe)
1568 handle_singlestep(utask, regs);
1569 else
1570 handle_swbp(regs);
1571}
1572
1573
1574
1575
1576
1577int uprobe_pre_sstep_notifier(struct pt_regs *regs)
1578{
1579 if (!current->mm || !test_bit(MMF_HAS_UPROBES, ¤t->mm->flags))
1580 return 0;
1581
1582 set_thread_flag(TIF_UPROBE);
1583 return 1;
1584}
1585
1586
1587
1588
1589
1590int uprobe_post_sstep_notifier(struct pt_regs *regs)
1591{
1592 struct uprobe_task *utask = current->utask;
1593
1594 if (!current->mm || !utask || !utask->active_uprobe)
1595
1596 return 0;
1597
1598 utask->state = UTASK_SSTEP_ACK;
1599 set_thread_flag(TIF_UPROBE);
1600 return 1;
1601}
1602
1603static struct notifier_block uprobe_exception_nb = {
1604 .notifier_call = arch_uprobe_exception_notify,
1605 .priority = INT_MAX-1,
1606};
1607
1608static int __init init_uprobes(void)
1609{
1610 int i;
1611
1612 for (i = 0; i < UPROBES_HASH_SZ; i++) {
1613 mutex_init(&uprobes_mutex[i]);
1614 mutex_init(&uprobes_mmap_mutex[i]);
1615 }
1616
1617 if (percpu_init_rwsem(&dup_mmap_sem))
1618 return -ENOMEM;
1619
1620 return register_die_notifier(&uprobe_exception_nb);
1621}
1622module_init(init_uprobes);
1623
1624static void __exit exit_uprobes(void)
1625{
1626}
1627module_exit(exit_uprobes);
1628