Commit | Line | Data |
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2b144498 | 1 | /* |
7b2d81d4 | 2 | * User-space Probes (UProbes) |
2b144498 SD |
3 | * |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License as published by | |
6 | * the Free Software Foundation; either version 2 of the License, or | |
7 | * (at your option) any later version. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | * | |
14 | * You should have received a copy of the GNU General Public License | |
15 | * along with this program; if not, write to the Free Software | |
16 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
17 | * | |
35aa621b | 18 | * Copyright (C) IBM Corporation, 2008-2012 |
2b144498 SD |
19 | * Authors: |
20 | * Srikar Dronamraju | |
21 | * Jim Keniston | |
35aa621b | 22 | * Copyright (C) 2011-2012 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> |
2b144498 SD |
23 | */ |
24 | ||
25 | #include <linux/kernel.h> | |
26 | #include <linux/highmem.h> | |
27 | #include <linux/pagemap.h> /* read_mapping_page */ | |
28 | #include <linux/slab.h> | |
29 | #include <linux/sched.h> | |
30 | #include <linux/rmap.h> /* anon_vma_prepare */ | |
31 | #include <linux/mmu_notifier.h> /* set_pte_at_notify */ | |
32 | #include <linux/swap.h> /* try_to_free_swap */ | |
0326f5a9 SD |
33 | #include <linux/ptrace.h> /* user_enable_single_step */ |
34 | #include <linux/kdebug.h> /* notifier mechanism */ | |
7b2d81d4 | 35 | |
2b144498 SD |
36 | #include <linux/uprobes.h> |
37 | ||
d4b3b638 SD |
38 | #define UINSNS_PER_PAGE (PAGE_SIZE/UPROBE_XOL_SLOT_BYTES) |
39 | #define MAX_UPROBE_XOL_SLOTS UINSNS_PER_PAGE | |
40 | ||
2b144498 | 41 | static struct rb_root uprobes_tree = RB_ROOT; |
7b2d81d4 | 42 | |
2b144498 SD |
43 | static DEFINE_SPINLOCK(uprobes_treelock); /* serialize rbtree access */ |
44 | ||
45 | #define UPROBES_HASH_SZ 13 | |
7b2d81d4 | 46 | |
c5784de2 PZ |
47 | /* |
48 | * We need separate register/unregister and mmap/munmap lock hashes because | |
49 | * of mmap_sem nesting. | |
50 | * | |
51 | * uprobe_register() needs to install probes on (potentially) all processes | |
52 | * and thus needs to acquire multiple mmap_sems (consequtively, not | |
53 | * concurrently), whereas uprobe_mmap() is called while holding mmap_sem | |
54 | * for the particular process doing the mmap. | |
55 | * | |
56 | * uprobe_register()->register_for_each_vma() needs to drop/acquire mmap_sem | |
57 | * because of lock order against i_mmap_mutex. This means there's a hole in | |
58 | * the register vma iteration where a mmap() can happen. | |
59 | * | |
60 | * Thus uprobe_register() can race with uprobe_mmap() and we can try and | |
61 | * install a probe where one is already installed. | |
62 | */ | |
63 | ||
2b144498 SD |
64 | /* serialize (un)register */ |
65 | static struct mutex uprobes_mutex[UPROBES_HASH_SZ]; | |
7b2d81d4 IM |
66 | |
67 | #define uprobes_hash(v) (&uprobes_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ]) | |
2b144498 SD |
68 | |
69 | /* serialize uprobe->pending_list */ | |
70 | static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ]; | |
7b2d81d4 | 71 | #define uprobes_mmap_hash(v) (&uprobes_mmap_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ]) |
2b144498 SD |
72 | |
73 | /* | |
7b2d81d4 | 74 | * uprobe_events allows us to skip the uprobe_mmap if there are no uprobe |
2b144498 SD |
75 | * events active at this time. Probably a fine grained per inode count is |
76 | * better? | |
77 | */ | |
78 | static atomic_t uprobe_events = ATOMIC_INIT(0); | |
79 | ||
3ff54efd SD |
80 | struct uprobe { |
81 | struct rb_node rb_node; /* node in the rb tree */ | |
82 | atomic_t ref; | |
83 | struct rw_semaphore consumer_rwsem; | |
84 | struct list_head pending_list; | |
85 | struct uprobe_consumer *consumers; | |
86 | struct inode *inode; /* Also hold a ref to inode */ | |
87 | loff_t offset; | |
88 | int flags; | |
89 | struct arch_uprobe arch; | |
90 | }; | |
91 | ||
2b144498 SD |
92 | /* |
93 | * valid_vma: Verify if the specified vma is an executable vma | |
94 | * Relax restrictions while unregistering: vm_flags might have | |
95 | * changed after breakpoint was inserted. | |
96 | * - is_register: indicates if we are in register context. | |
97 | * - Return 1 if the specified virtual address is in an | |
98 | * executable vma. | |
99 | */ | |
100 | static bool valid_vma(struct vm_area_struct *vma, bool is_register) | |
101 | { | |
102 | if (!vma->vm_file) | |
103 | return false; | |
104 | ||
105 | if (!is_register) | |
106 | return true; | |
107 | ||
ea131377 ON |
108 | if ((vma->vm_flags & (VM_HUGETLB|VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)) |
109 | == (VM_READ|VM_EXEC)) | |
2b144498 SD |
110 | return true; |
111 | ||
112 | return false; | |
113 | } | |
114 | ||
115 | static loff_t vma_address(struct vm_area_struct *vma, loff_t offset) | |
116 | { | |
117 | loff_t vaddr; | |
118 | ||
119 | vaddr = vma->vm_start + offset; | |
120 | vaddr -= vma->vm_pgoff << PAGE_SHIFT; | |
7b2d81d4 | 121 | |
2b144498 SD |
122 | return vaddr; |
123 | } | |
124 | ||
125 | /** | |
126 | * __replace_page - replace page in vma by new page. | |
127 | * based on replace_page in mm/ksm.c | |
128 | * | |
129 | * @vma: vma that holds the pte pointing to page | |
130 | * @page: the cowed page we are replacing by kpage | |
131 | * @kpage: the modified page we replace page by | |
132 | * | |
133 | * Returns 0 on success, -EFAULT on failure. | |
134 | */ | |
7b2d81d4 | 135 | static int __replace_page(struct vm_area_struct *vma, struct page *page, struct page *kpage) |
2b144498 SD |
136 | { |
137 | struct mm_struct *mm = vma->vm_mm; | |
2b144498 | 138 | unsigned long addr; |
5323ce71 ON |
139 | spinlock_t *ptl; |
140 | pte_t *ptep; | |
2b144498 SD |
141 | |
142 | addr = page_address_in_vma(page, vma); | |
143 | if (addr == -EFAULT) | |
5323ce71 | 144 | return -EFAULT; |
2b144498 | 145 | |
5323ce71 | 146 | ptep = page_check_address(page, mm, addr, &ptl, 0); |
2b144498 | 147 | if (!ptep) |
5323ce71 | 148 | return -EAGAIN; |
2b144498 SD |
149 | |
150 | get_page(kpage); | |
151 | page_add_new_anon_rmap(kpage, vma, addr); | |
152 | ||
7396fa81 SD |
153 | if (!PageAnon(page)) { |
154 | dec_mm_counter(mm, MM_FILEPAGES); | |
155 | inc_mm_counter(mm, MM_ANONPAGES); | |
156 | } | |
157 | ||
2b144498 SD |
158 | flush_cache_page(vma, addr, pte_pfn(*ptep)); |
159 | ptep_clear_flush(vma, addr, ptep); | |
160 | set_pte_at_notify(mm, addr, ptep, mk_pte(kpage, vma->vm_page_prot)); | |
161 | ||
162 | page_remove_rmap(page); | |
163 | if (!page_mapped(page)) | |
164 | try_to_free_swap(page); | |
165 | put_page(page); | |
166 | pte_unmap_unlock(ptep, ptl); | |
2b144498 | 167 | |
5323ce71 | 168 | return 0; |
2b144498 SD |
169 | } |
170 | ||
171 | /** | |
5cb4ac3a | 172 | * is_swbp_insn - check if instruction is breakpoint instruction. |
2b144498 | 173 | * @insn: instruction to be checked. |
5cb4ac3a | 174 | * Default implementation of is_swbp_insn |
2b144498 SD |
175 | * Returns true if @insn is a breakpoint instruction. |
176 | */ | |
5cb4ac3a | 177 | bool __weak is_swbp_insn(uprobe_opcode_t *insn) |
2b144498 | 178 | { |
5cb4ac3a | 179 | return *insn == UPROBE_SWBP_INSN; |
2b144498 SD |
180 | } |
181 | ||
182 | /* | |
183 | * NOTE: | |
184 | * Expect the breakpoint instruction to be the smallest size instruction for | |
185 | * the architecture. If an arch has variable length instruction and the | |
186 | * breakpoint instruction is not of the smallest length instruction | |
187 | * supported by that architecture then we need to modify read_opcode / | |
188 | * write_opcode accordingly. This would never be a problem for archs that | |
189 | * have fixed length instructions. | |
190 | */ | |
191 | ||
192 | /* | |
193 | * write_opcode - write the opcode at a given virtual address. | |
e3343e6a | 194 | * @auprobe: arch breakpointing information. |
2b144498 | 195 | * @mm: the probed process address space. |
2b144498 SD |
196 | * @vaddr: the virtual address to store the opcode. |
197 | * @opcode: opcode to be written at @vaddr. | |
198 | * | |
199 | * Called with mm->mmap_sem held (for read and with a reference to | |
200 | * mm). | |
201 | * | |
202 | * For mm @mm, write the opcode at @vaddr. | |
203 | * Return 0 (success) or a negative errno. | |
204 | */ | |
e3343e6a | 205 | static int write_opcode(struct arch_uprobe *auprobe, struct mm_struct *mm, |
2b144498 SD |
206 | unsigned long vaddr, uprobe_opcode_t opcode) |
207 | { | |
208 | struct page *old_page, *new_page; | |
2b144498 SD |
209 | void *vaddr_old, *vaddr_new; |
210 | struct vm_area_struct *vma; | |
2b144498 | 211 | int ret; |
f403072c | 212 | |
5323ce71 | 213 | retry: |
2b144498 SD |
214 | /* Read the page with vaddr into memory */ |
215 | ret = get_user_pages(NULL, mm, vaddr, 1, 0, 0, &old_page, &vma); | |
216 | if (ret <= 0) | |
217 | return ret; | |
7b2d81d4 | 218 | |
2b144498 SD |
219 | ret = -ENOMEM; |
220 | new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr); | |
221 | if (!new_page) | |
222 | goto put_out; | |
223 | ||
224 | __SetPageUptodate(new_page); | |
225 | ||
226 | /* | |
227 | * lock page will serialize against do_wp_page()'s | |
228 | * PageAnon() handling | |
229 | */ | |
230 | lock_page(old_page); | |
231 | /* copy the page now that we've got it stable */ | |
232 | vaddr_old = kmap_atomic(old_page); | |
233 | vaddr_new = kmap_atomic(new_page); | |
234 | ||
235 | memcpy(vaddr_new, vaddr_old, PAGE_SIZE); | |
d9c4a30e | 236 | memcpy(vaddr_new + (vaddr & ~PAGE_MASK), &opcode, UPROBE_SWBP_INSN_SIZE); |
2b144498 SD |
237 | |
238 | kunmap_atomic(vaddr_new); | |
239 | kunmap_atomic(vaddr_old); | |
240 | ||
241 | ret = anon_vma_prepare(vma); | |
242 | if (ret) | |
243 | goto unlock_out; | |
244 | ||
245 | lock_page(new_page); | |
246 | ret = __replace_page(vma, old_page, new_page); | |
247 | unlock_page(new_page); | |
248 | ||
249 | unlock_out: | |
250 | unlock_page(old_page); | |
251 | page_cache_release(new_page); | |
252 | ||
253 | put_out: | |
7b2d81d4 IM |
254 | put_page(old_page); |
255 | ||
5323ce71 ON |
256 | if (unlikely(ret == -EAGAIN)) |
257 | goto retry; | |
2b144498 SD |
258 | return ret; |
259 | } | |
260 | ||
261 | /** | |
262 | * read_opcode - read the opcode at a given virtual address. | |
263 | * @mm: the probed process address space. | |
264 | * @vaddr: the virtual address to read the opcode. | |
265 | * @opcode: location to store the read opcode. | |
266 | * | |
267 | * Called with mm->mmap_sem held (for read and with a reference to | |
268 | * mm. | |
269 | * | |
270 | * For mm @mm, read the opcode at @vaddr and store it in @opcode. | |
271 | * Return 0 (success) or a negative errno. | |
272 | */ | |
7b2d81d4 | 273 | static int read_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t *opcode) |
2b144498 SD |
274 | { |
275 | struct page *page; | |
276 | void *vaddr_new; | |
277 | int ret; | |
278 | ||
a3d7bb47 | 279 | ret = get_user_pages(NULL, mm, vaddr, 1, 0, 1, &page, NULL); |
2b144498 SD |
280 | if (ret <= 0) |
281 | return ret; | |
282 | ||
283 | lock_page(page); | |
284 | vaddr_new = kmap_atomic(page); | |
285 | vaddr &= ~PAGE_MASK; | |
5cb4ac3a | 286 | memcpy(opcode, vaddr_new + vaddr, UPROBE_SWBP_INSN_SIZE); |
2b144498 SD |
287 | kunmap_atomic(vaddr_new); |
288 | unlock_page(page); | |
7b2d81d4 IM |
289 | |
290 | put_page(page); | |
291 | ||
2b144498 SD |
292 | return 0; |
293 | } | |
294 | ||
5cb4ac3a | 295 | static int is_swbp_at_addr(struct mm_struct *mm, unsigned long vaddr) |
2b144498 SD |
296 | { |
297 | uprobe_opcode_t opcode; | |
7b2d81d4 | 298 | int result; |
2b144498 | 299 | |
c00b2750 ON |
300 | if (current->mm == mm) { |
301 | pagefault_disable(); | |
302 | result = __copy_from_user_inatomic(&opcode, (void __user*)vaddr, | |
303 | sizeof(opcode)); | |
304 | pagefault_enable(); | |
305 | ||
306 | if (likely(result == 0)) | |
307 | goto out; | |
308 | } | |
309 | ||
7b2d81d4 | 310 | result = read_opcode(mm, vaddr, &opcode); |
2b144498 SD |
311 | if (result) |
312 | return result; | |
c00b2750 | 313 | out: |
5cb4ac3a | 314 | if (is_swbp_insn(&opcode)) |
2b144498 SD |
315 | return 1; |
316 | ||
317 | return 0; | |
318 | } | |
319 | ||
320 | /** | |
5cb4ac3a | 321 | * set_swbp - store breakpoint at a given address. |
e3343e6a | 322 | * @auprobe: arch specific probepoint information. |
2b144498 | 323 | * @mm: the probed process address space. |
2b144498 SD |
324 | * @vaddr: the virtual address to insert the opcode. |
325 | * | |
326 | * For mm @mm, store the breakpoint instruction at @vaddr. | |
327 | * Return 0 (success) or a negative errno. | |
328 | */ | |
5cb4ac3a | 329 | int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) |
2b144498 | 330 | { |
7b2d81d4 | 331 | int result; |
c5784de2 PZ |
332 | /* |
333 | * See the comment near uprobes_hash(). | |
334 | */ | |
5cb4ac3a | 335 | result = is_swbp_at_addr(mm, vaddr); |
2b144498 SD |
336 | if (result == 1) |
337 | return -EEXIST; | |
338 | ||
339 | if (result) | |
340 | return result; | |
341 | ||
5cb4ac3a | 342 | return write_opcode(auprobe, mm, vaddr, UPROBE_SWBP_INSN); |
2b144498 SD |
343 | } |
344 | ||
345 | /** | |
346 | * set_orig_insn - Restore the original instruction. | |
347 | * @mm: the probed process address space. | |
e3343e6a | 348 | * @auprobe: arch specific probepoint information. |
2b144498 SD |
349 | * @vaddr: the virtual address to insert the opcode. |
350 | * @verify: if true, verify existance of breakpoint instruction. | |
351 | * | |
352 | * For mm @mm, restore the original opcode (opcode) at @vaddr. | |
353 | * Return 0 (success) or a negative errno. | |
354 | */ | |
7b2d81d4 | 355 | int __weak |
e3343e6a | 356 | set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr, bool verify) |
2b144498 SD |
357 | { |
358 | if (verify) { | |
7b2d81d4 | 359 | int result; |
2b144498 | 360 | |
5cb4ac3a | 361 | result = is_swbp_at_addr(mm, vaddr); |
2b144498 SD |
362 | if (!result) |
363 | return -EINVAL; | |
364 | ||
365 | if (result != 1) | |
366 | return result; | |
367 | } | |
e3343e6a | 368 | return write_opcode(auprobe, mm, vaddr, *(uprobe_opcode_t *)auprobe->insn); |
2b144498 SD |
369 | } |
370 | ||
371 | static int match_uprobe(struct uprobe *l, struct uprobe *r) | |
372 | { | |
373 | if (l->inode < r->inode) | |
374 | return -1; | |
7b2d81d4 | 375 | |
2b144498 SD |
376 | if (l->inode > r->inode) |
377 | return 1; | |
2b144498 | 378 | |
7b2d81d4 IM |
379 | if (l->offset < r->offset) |
380 | return -1; | |
381 | ||
382 | if (l->offset > r->offset) | |
383 | return 1; | |
2b144498 SD |
384 | |
385 | return 0; | |
386 | } | |
387 | ||
388 | static struct uprobe *__find_uprobe(struct inode *inode, loff_t offset) | |
389 | { | |
390 | struct uprobe u = { .inode = inode, .offset = offset }; | |
391 | struct rb_node *n = uprobes_tree.rb_node; | |
392 | struct uprobe *uprobe; | |
393 | int match; | |
394 | ||
395 | while (n) { | |
396 | uprobe = rb_entry(n, struct uprobe, rb_node); | |
397 | match = match_uprobe(&u, uprobe); | |
398 | if (!match) { | |
399 | atomic_inc(&uprobe->ref); | |
400 | return uprobe; | |
401 | } | |
7b2d81d4 | 402 | |
2b144498 SD |
403 | if (match < 0) |
404 | n = n->rb_left; | |
405 | else | |
406 | n = n->rb_right; | |
407 | } | |
408 | return NULL; | |
409 | } | |
410 | ||
411 | /* | |
412 | * Find a uprobe corresponding to a given inode:offset | |
413 | * Acquires uprobes_treelock | |
414 | */ | |
415 | static struct uprobe *find_uprobe(struct inode *inode, loff_t offset) | |
416 | { | |
417 | struct uprobe *uprobe; | |
418 | unsigned long flags; | |
419 | ||
420 | spin_lock_irqsave(&uprobes_treelock, flags); | |
421 | uprobe = __find_uprobe(inode, offset); | |
422 | spin_unlock_irqrestore(&uprobes_treelock, flags); | |
7b2d81d4 | 423 | |
2b144498 SD |
424 | return uprobe; |
425 | } | |
426 | ||
427 | static struct uprobe *__insert_uprobe(struct uprobe *uprobe) | |
428 | { | |
429 | struct rb_node **p = &uprobes_tree.rb_node; | |
430 | struct rb_node *parent = NULL; | |
431 | struct uprobe *u; | |
432 | int match; | |
433 | ||
434 | while (*p) { | |
435 | parent = *p; | |
436 | u = rb_entry(parent, struct uprobe, rb_node); | |
437 | match = match_uprobe(uprobe, u); | |
438 | if (!match) { | |
439 | atomic_inc(&u->ref); | |
440 | return u; | |
441 | } | |
442 | ||
443 | if (match < 0) | |
444 | p = &parent->rb_left; | |
445 | else | |
446 | p = &parent->rb_right; | |
447 | ||
448 | } | |
7b2d81d4 | 449 | |
2b144498 SD |
450 | u = NULL; |
451 | rb_link_node(&uprobe->rb_node, parent, p); | |
452 | rb_insert_color(&uprobe->rb_node, &uprobes_tree); | |
453 | /* get access + creation ref */ | |
454 | atomic_set(&uprobe->ref, 2); | |
7b2d81d4 | 455 | |
2b144498 SD |
456 | return u; |
457 | } | |
458 | ||
459 | /* | |
7b2d81d4 | 460 | * Acquire uprobes_treelock. |
2b144498 SD |
461 | * Matching uprobe already exists in rbtree; |
462 | * increment (access refcount) and return the matching uprobe. | |
463 | * | |
464 | * No matching uprobe; insert the uprobe in rb_tree; | |
465 | * get a double refcount (access + creation) and return NULL. | |
466 | */ | |
467 | static struct uprobe *insert_uprobe(struct uprobe *uprobe) | |
468 | { | |
469 | unsigned long flags; | |
470 | struct uprobe *u; | |
471 | ||
472 | spin_lock_irqsave(&uprobes_treelock, flags); | |
473 | u = __insert_uprobe(uprobe); | |
474 | spin_unlock_irqrestore(&uprobes_treelock, flags); | |
7b2d81d4 | 475 | |
0326f5a9 SD |
476 | /* For now assume that the instruction need not be single-stepped */ |
477 | uprobe->flags |= UPROBE_SKIP_SSTEP; | |
478 | ||
2b144498 SD |
479 | return u; |
480 | } | |
481 | ||
482 | static void put_uprobe(struct uprobe *uprobe) | |
483 | { | |
484 | if (atomic_dec_and_test(&uprobe->ref)) | |
485 | kfree(uprobe); | |
486 | } | |
487 | ||
488 | static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset) | |
489 | { | |
490 | struct uprobe *uprobe, *cur_uprobe; | |
491 | ||
492 | uprobe = kzalloc(sizeof(struct uprobe), GFP_KERNEL); | |
493 | if (!uprobe) | |
494 | return NULL; | |
495 | ||
496 | uprobe->inode = igrab(inode); | |
497 | uprobe->offset = offset; | |
498 | init_rwsem(&uprobe->consumer_rwsem); | |
2b144498 SD |
499 | |
500 | /* add to uprobes_tree, sorted on inode:offset */ | |
501 | cur_uprobe = insert_uprobe(uprobe); | |
502 | ||
503 | /* a uprobe exists for this inode:offset combination */ | |
504 | if (cur_uprobe) { | |
505 | kfree(uprobe); | |
506 | uprobe = cur_uprobe; | |
507 | iput(inode); | |
7b2d81d4 | 508 | } else { |
2b144498 | 509 | atomic_inc(&uprobe_events); |
7b2d81d4 IM |
510 | } |
511 | ||
2b144498 SD |
512 | return uprobe; |
513 | } | |
514 | ||
0326f5a9 SD |
515 | static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs) |
516 | { | |
517 | struct uprobe_consumer *uc; | |
518 | ||
519 | if (!(uprobe->flags & UPROBE_RUN_HANDLER)) | |
520 | return; | |
521 | ||
522 | down_read(&uprobe->consumer_rwsem); | |
523 | for (uc = uprobe->consumers; uc; uc = uc->next) { | |
524 | if (!uc->filter || uc->filter(uc, current)) | |
525 | uc->handler(uc, regs); | |
526 | } | |
527 | up_read(&uprobe->consumer_rwsem); | |
528 | } | |
529 | ||
2b144498 | 530 | /* Returns the previous consumer */ |
7b2d81d4 | 531 | static struct uprobe_consumer * |
e3343e6a | 532 | consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc) |
2b144498 SD |
533 | { |
534 | down_write(&uprobe->consumer_rwsem); | |
e3343e6a SD |
535 | uc->next = uprobe->consumers; |
536 | uprobe->consumers = uc; | |
2b144498 | 537 | up_write(&uprobe->consumer_rwsem); |
7b2d81d4 | 538 | |
e3343e6a | 539 | return uc->next; |
2b144498 SD |
540 | } |
541 | ||
542 | /* | |
e3343e6a SD |
543 | * For uprobe @uprobe, delete the consumer @uc. |
544 | * Return true if the @uc is deleted successfully | |
2b144498 SD |
545 | * or return false. |
546 | */ | |
e3343e6a | 547 | static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *uc) |
2b144498 SD |
548 | { |
549 | struct uprobe_consumer **con; | |
550 | bool ret = false; | |
551 | ||
552 | down_write(&uprobe->consumer_rwsem); | |
553 | for (con = &uprobe->consumers; *con; con = &(*con)->next) { | |
e3343e6a SD |
554 | if (*con == uc) { |
555 | *con = uc->next; | |
2b144498 SD |
556 | ret = true; |
557 | break; | |
558 | } | |
559 | } | |
560 | up_write(&uprobe->consumer_rwsem); | |
7b2d81d4 | 561 | |
2b144498 SD |
562 | return ret; |
563 | } | |
564 | ||
e3343e6a | 565 | static int |
d436615e | 566 | __copy_insn(struct address_space *mapping, struct file *filp, char *insn, |
593609a5 | 567 | unsigned long nbytes, loff_t offset) |
2b144498 | 568 | { |
2b144498 SD |
569 | struct page *page; |
570 | void *vaddr; | |
593609a5 ON |
571 | unsigned long off; |
572 | pgoff_t idx; | |
2b144498 SD |
573 | |
574 | if (!filp) | |
575 | return -EINVAL; | |
576 | ||
cc359d18 ON |
577 | if (!mapping->a_ops->readpage) |
578 | return -EIO; | |
579 | ||
593609a5 ON |
580 | idx = offset >> PAGE_CACHE_SHIFT; |
581 | off = offset & ~PAGE_MASK; | |
2b144498 SD |
582 | |
583 | /* | |
584 | * Ensure that the page that has the original instruction is | |
585 | * populated and in page-cache. | |
586 | */ | |
587 | page = read_mapping_page(mapping, idx, filp); | |
588 | if (IS_ERR(page)) | |
589 | return PTR_ERR(page); | |
590 | ||
591 | vaddr = kmap_atomic(page); | |
593609a5 | 592 | memcpy(insn, vaddr + off, nbytes); |
2b144498 SD |
593 | kunmap_atomic(vaddr); |
594 | page_cache_release(page); | |
7b2d81d4 | 595 | |
2b144498 SD |
596 | return 0; |
597 | } | |
598 | ||
d436615e | 599 | static int copy_insn(struct uprobe *uprobe, struct file *filp) |
2b144498 SD |
600 | { |
601 | struct address_space *mapping; | |
2b144498 | 602 | unsigned long nbytes; |
7b2d81d4 | 603 | int bytes; |
2b144498 | 604 | |
d436615e | 605 | nbytes = PAGE_SIZE - (uprobe->offset & ~PAGE_MASK); |
2b144498 SD |
606 | mapping = uprobe->inode->i_mapping; |
607 | ||
608 | /* Instruction at end of binary; copy only available bytes */ | |
609 | if (uprobe->offset + MAX_UINSN_BYTES > uprobe->inode->i_size) | |
610 | bytes = uprobe->inode->i_size - uprobe->offset; | |
611 | else | |
612 | bytes = MAX_UINSN_BYTES; | |
613 | ||
614 | /* Instruction at the page-boundary; copy bytes in second page */ | |
615 | if (nbytes < bytes) { | |
fc36f595 ON |
616 | int err = __copy_insn(mapping, filp, uprobe->arch.insn + nbytes, |
617 | bytes - nbytes, uprobe->offset + nbytes); | |
618 | if (err) | |
619 | return err; | |
2b144498 SD |
620 | bytes = nbytes; |
621 | } | |
d436615e | 622 | return __copy_insn(mapping, filp, uprobe->arch.insn, bytes, uprobe->offset); |
2b144498 SD |
623 | } |
624 | ||
682968e0 SD |
625 | /* |
626 | * How mm->uprobes_state.count gets updated | |
627 | * uprobe_mmap() increments the count if | |
628 | * - it successfully adds a breakpoint. | |
629 | * - it cannot add a breakpoint, but sees that there is a underlying | |
630 | * breakpoint (via a is_swbp_at_addr()). | |
631 | * | |
632 | * uprobe_munmap() decrements the count if | |
633 | * - it sees a underlying breakpoint, (via is_swbp_at_addr) | |
634 | * (Subsequent uprobe_unregister wouldnt find the breakpoint | |
635 | * unless a uprobe_mmap kicks in, since the old vma would be | |
636 | * dropped just after uprobe_munmap.) | |
637 | * | |
638 | * uprobe_register increments the count if: | |
639 | * - it successfully adds a breakpoint. | |
640 | * | |
641 | * uprobe_unregister decrements the count if: | |
642 | * - it sees a underlying breakpoint and removes successfully. | |
643 | * (via is_swbp_at_addr) | |
644 | * (Subsequent uprobe_munmap wouldnt find the breakpoint | |
645 | * since there is no underlying breakpoint after the | |
646 | * breakpoint removal.) | |
647 | */ | |
e3343e6a SD |
648 | static int |
649 | install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, | |
816c03fb | 650 | struct vm_area_struct *vma, unsigned long vaddr) |
2b144498 | 651 | { |
2b144498 SD |
652 | int ret; |
653 | ||
654 | /* | |
655 | * If probe is being deleted, unregister thread could be done with | |
656 | * the vma-rmap-walk through. Adding a probe now can be fatal since | |
657 | * nobody will be able to cleanup. Also we could be from fork or | |
658 | * mremap path, where the probe might have already been inserted. | |
659 | * Hence behave as if probe already existed. | |
660 | */ | |
661 | if (!uprobe->consumers) | |
662 | return -EEXIST; | |
663 | ||
900771a4 | 664 | if (!(uprobe->flags & UPROBE_COPY_INSN)) { |
d436615e | 665 | ret = copy_insn(uprobe, vma->vm_file); |
2b144498 SD |
666 | if (ret) |
667 | return ret; | |
668 | ||
5cb4ac3a | 669 | if (is_swbp_insn((uprobe_opcode_t *)uprobe->arch.insn)) |
c1914a09 | 670 | return -ENOTSUPP; |
2b144498 | 671 | |
816c03fb | 672 | ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, vaddr); |
2b144498 SD |
673 | if (ret) |
674 | return ret; | |
675 | ||
d9c4a30e ON |
676 | /* write_opcode() assumes we don't cross page boundary */ |
677 | BUG_ON((uprobe->offset & ~PAGE_MASK) + | |
678 | UPROBE_SWBP_INSN_SIZE > PAGE_SIZE); | |
679 | ||
900771a4 | 680 | uprobe->flags |= UPROBE_COPY_INSN; |
2b144498 | 681 | } |
682968e0 SD |
682 | |
683 | /* | |
684 | * Ideally, should be updating the probe count after the breakpoint | |
685 | * has been successfully inserted. However a thread could hit the | |
686 | * breakpoint we just inserted even before the probe count is | |
687 | * incremented. If this is the first breakpoint placed, breakpoint | |
688 | * notifier might ignore uprobes and pass the trap to the thread. | |
689 | * Hence increment before and decrement on failure. | |
690 | */ | |
691 | atomic_inc(&mm->uprobes_state.count); | |
816c03fb | 692 | ret = set_swbp(&uprobe->arch, mm, vaddr); |
682968e0 SD |
693 | if (ret) |
694 | atomic_dec(&mm->uprobes_state.count); | |
2b144498 SD |
695 | |
696 | return ret; | |
697 | } | |
698 | ||
e3343e6a | 699 | static void |
816c03fb | 700 | remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, unsigned long vaddr) |
2b144498 | 701 | { |
816c03fb | 702 | if (!set_orig_insn(&uprobe->arch, mm, vaddr, true)) |
682968e0 | 703 | atomic_dec(&mm->uprobes_state.count); |
2b144498 SD |
704 | } |
705 | ||
0326f5a9 | 706 | /* |
778b032d ON |
707 | * There could be threads that have already hit the breakpoint. They |
708 | * will recheck the current insn and restart if find_uprobe() fails. | |
709 | * See find_active_uprobe(). | |
0326f5a9 | 710 | */ |
2b144498 SD |
711 | static void delete_uprobe(struct uprobe *uprobe) |
712 | { | |
713 | unsigned long flags; | |
714 | ||
715 | spin_lock_irqsave(&uprobes_treelock, flags); | |
716 | rb_erase(&uprobe->rb_node, &uprobes_tree); | |
717 | spin_unlock_irqrestore(&uprobes_treelock, flags); | |
718 | iput(uprobe->inode); | |
719 | put_uprobe(uprobe); | |
720 | atomic_dec(&uprobe_events); | |
721 | } | |
722 | ||
26872090 ON |
723 | struct map_info { |
724 | struct map_info *next; | |
725 | struct mm_struct *mm; | |
816c03fb | 726 | unsigned long vaddr; |
26872090 ON |
727 | }; |
728 | ||
729 | static inline struct map_info *free_map_info(struct map_info *info) | |
2b144498 | 730 | { |
26872090 ON |
731 | struct map_info *next = info->next; |
732 | kfree(info); | |
733 | return next; | |
734 | } | |
735 | ||
736 | static struct map_info * | |
737 | build_map_info(struct address_space *mapping, loff_t offset, bool is_register) | |
738 | { | |
739 | unsigned long pgoff = offset >> PAGE_SHIFT; | |
2b144498 SD |
740 | struct prio_tree_iter iter; |
741 | struct vm_area_struct *vma; | |
26872090 ON |
742 | struct map_info *curr = NULL; |
743 | struct map_info *prev = NULL; | |
744 | struct map_info *info; | |
745 | int more = 0; | |
2b144498 | 746 | |
26872090 ON |
747 | again: |
748 | mutex_lock(&mapping->i_mmap_mutex); | |
2b144498 SD |
749 | vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) { |
750 | if (!valid_vma(vma, is_register)) | |
751 | continue; | |
752 | ||
7a5bfb66 ON |
753 | if (!prev && !more) { |
754 | /* | |
755 | * Needs GFP_NOWAIT to avoid i_mmap_mutex recursion through | |
756 | * reclaim. This is optimistic, no harm done if it fails. | |
757 | */ | |
758 | prev = kmalloc(sizeof(struct map_info), | |
759 | GFP_NOWAIT | __GFP_NOMEMALLOC | __GFP_NOWARN); | |
760 | if (prev) | |
761 | prev->next = NULL; | |
762 | } | |
26872090 ON |
763 | if (!prev) { |
764 | more++; | |
765 | continue; | |
2b144498 | 766 | } |
2b144498 | 767 | |
26872090 ON |
768 | if (!atomic_inc_not_zero(&vma->vm_mm->mm_users)) |
769 | continue; | |
7b2d81d4 | 770 | |
26872090 ON |
771 | info = prev; |
772 | prev = prev->next; | |
773 | info->next = curr; | |
774 | curr = info; | |
2b144498 | 775 | |
26872090 ON |
776 | info->mm = vma->vm_mm; |
777 | info->vaddr = vma_address(vma, offset); | |
778 | } | |
2b144498 SD |
779 | mutex_unlock(&mapping->i_mmap_mutex); |
780 | ||
26872090 ON |
781 | if (!more) |
782 | goto out; | |
783 | ||
784 | prev = curr; | |
785 | while (curr) { | |
786 | mmput(curr->mm); | |
787 | curr = curr->next; | |
788 | } | |
7b2d81d4 | 789 | |
26872090 ON |
790 | do { |
791 | info = kmalloc(sizeof(struct map_info), GFP_KERNEL); | |
792 | if (!info) { | |
793 | curr = ERR_PTR(-ENOMEM); | |
794 | goto out; | |
795 | } | |
796 | info->next = prev; | |
797 | prev = info; | |
798 | } while (--more); | |
799 | ||
800 | goto again; | |
801 | out: | |
802 | while (prev) | |
803 | prev = free_map_info(prev); | |
804 | return curr; | |
2b144498 SD |
805 | } |
806 | ||
807 | static int register_for_each_vma(struct uprobe *uprobe, bool is_register) | |
808 | { | |
26872090 ON |
809 | struct map_info *info; |
810 | int err = 0; | |
2b144498 | 811 | |
26872090 ON |
812 | info = build_map_info(uprobe->inode->i_mapping, |
813 | uprobe->offset, is_register); | |
814 | if (IS_ERR(info)) | |
815 | return PTR_ERR(info); | |
7b2d81d4 | 816 | |
26872090 ON |
817 | while (info) { |
818 | struct mm_struct *mm = info->mm; | |
819 | struct vm_area_struct *vma; | |
7b2d81d4 | 820 | |
26872090 ON |
821 | if (err) |
822 | goto free; | |
7b2d81d4 | 823 | |
77fc4af1 | 824 | down_write(&mm->mmap_sem); |
26872090 ON |
825 | vma = find_vma(mm, (unsigned long)info->vaddr); |
826 | if (!vma || !valid_vma(vma, is_register)) | |
827 | goto unlock; | |
828 | ||
2b144498 | 829 | if (vma->vm_file->f_mapping->host != uprobe->inode || |
816c03fb | 830 | vma_address(vma, uprobe->offset) != info->vaddr) |
26872090 | 831 | goto unlock; |
2b144498 | 832 | |
2b144498 | 833 | if (is_register) { |
26872090 | 834 | err = install_breakpoint(uprobe, mm, vma, info->vaddr); |
c5784de2 PZ |
835 | /* |
836 | * We can race against uprobe_mmap(), see the | |
837 | * comment near uprobe_hash(). | |
838 | */ | |
26872090 ON |
839 | if (err == -EEXIST) |
840 | err = 0; | |
841 | } else { | |
842 | remove_breakpoint(uprobe, mm, info->vaddr); | |
2b144498 | 843 | } |
26872090 ON |
844 | unlock: |
845 | up_write(&mm->mmap_sem); | |
846 | free: | |
847 | mmput(mm); | |
848 | info = free_map_info(info); | |
2b144498 | 849 | } |
7b2d81d4 | 850 | |
26872090 | 851 | return err; |
2b144498 SD |
852 | } |
853 | ||
7b2d81d4 | 854 | static int __uprobe_register(struct uprobe *uprobe) |
2b144498 SD |
855 | { |
856 | return register_for_each_vma(uprobe, true); | |
857 | } | |
858 | ||
7b2d81d4 | 859 | static void __uprobe_unregister(struct uprobe *uprobe) |
2b144498 SD |
860 | { |
861 | if (!register_for_each_vma(uprobe, false)) | |
862 | delete_uprobe(uprobe); | |
863 | ||
864 | /* TODO : cant unregister? schedule a worker thread */ | |
865 | } | |
866 | ||
867 | /* | |
7b2d81d4 | 868 | * uprobe_register - register a probe |
2b144498 SD |
869 | * @inode: the file in which the probe has to be placed. |
870 | * @offset: offset from the start of the file. | |
e3343e6a | 871 | * @uc: information on howto handle the probe.. |
2b144498 | 872 | * |
7b2d81d4 | 873 | * Apart from the access refcount, uprobe_register() takes a creation |
2b144498 SD |
874 | * refcount (thro alloc_uprobe) if and only if this @uprobe is getting |
875 | * inserted into the rbtree (i.e first consumer for a @inode:@offset | |
7b2d81d4 | 876 | * tuple). Creation refcount stops uprobe_unregister from freeing the |
2b144498 | 877 | * @uprobe even before the register operation is complete. Creation |
e3343e6a | 878 | * refcount is released when the last @uc for the @uprobe |
2b144498 SD |
879 | * unregisters. |
880 | * | |
881 | * Return errno if it cannot successully install probes | |
882 | * else return 0 (success) | |
883 | */ | |
e3343e6a | 884 | int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) |
2b144498 SD |
885 | { |
886 | struct uprobe *uprobe; | |
7b2d81d4 | 887 | int ret; |
2b144498 | 888 | |
e3343e6a | 889 | if (!inode || !uc || uc->next) |
7b2d81d4 | 890 | return -EINVAL; |
2b144498 SD |
891 | |
892 | if (offset > i_size_read(inode)) | |
7b2d81d4 | 893 | return -EINVAL; |
2b144498 SD |
894 | |
895 | ret = 0; | |
896 | mutex_lock(uprobes_hash(inode)); | |
897 | uprobe = alloc_uprobe(inode, offset); | |
7b2d81d4 | 898 | |
e3343e6a | 899 | if (uprobe && !consumer_add(uprobe, uc)) { |
7b2d81d4 | 900 | ret = __uprobe_register(uprobe); |
2b144498 SD |
901 | if (ret) { |
902 | uprobe->consumers = NULL; | |
7b2d81d4 IM |
903 | __uprobe_unregister(uprobe); |
904 | } else { | |
900771a4 | 905 | uprobe->flags |= UPROBE_RUN_HANDLER; |
7b2d81d4 | 906 | } |
2b144498 SD |
907 | } |
908 | ||
909 | mutex_unlock(uprobes_hash(inode)); | |
910 | put_uprobe(uprobe); | |
911 | ||
912 | return ret; | |
913 | } | |
914 | ||
915 | /* | |
7b2d81d4 | 916 | * uprobe_unregister - unregister a already registered probe. |
2b144498 SD |
917 | * @inode: the file in which the probe has to be removed. |
918 | * @offset: offset from the start of the file. | |
e3343e6a | 919 | * @uc: identify which probe if multiple probes are colocated. |
2b144498 | 920 | */ |
e3343e6a | 921 | void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) |
2b144498 | 922 | { |
7b2d81d4 | 923 | struct uprobe *uprobe; |
2b144498 | 924 | |
e3343e6a | 925 | if (!inode || !uc) |
2b144498 SD |
926 | return; |
927 | ||
928 | uprobe = find_uprobe(inode, offset); | |
929 | if (!uprobe) | |
930 | return; | |
931 | ||
932 | mutex_lock(uprobes_hash(inode)); | |
2b144498 | 933 | |
e3343e6a | 934 | if (consumer_del(uprobe, uc)) { |
7b2d81d4 IM |
935 | if (!uprobe->consumers) { |
936 | __uprobe_unregister(uprobe); | |
900771a4 | 937 | uprobe->flags &= ~UPROBE_RUN_HANDLER; |
7b2d81d4 | 938 | } |
2b144498 SD |
939 | } |
940 | ||
2b144498 SD |
941 | mutex_unlock(uprobes_hash(inode)); |
942 | if (uprobe) | |
943 | put_uprobe(uprobe); | |
944 | } | |
945 | ||
946 | /* | |
947 | * Of all the nodes that correspond to the given inode, return the node | |
948 | * with the least offset. | |
949 | */ | |
950 | static struct rb_node *find_least_offset_node(struct inode *inode) | |
951 | { | |
952 | struct uprobe u = { .inode = inode, .offset = 0}; | |
953 | struct rb_node *n = uprobes_tree.rb_node; | |
954 | struct rb_node *close_node = NULL; | |
955 | struct uprobe *uprobe; | |
956 | int match; | |
957 | ||
958 | while (n) { | |
959 | uprobe = rb_entry(n, struct uprobe, rb_node); | |
960 | match = match_uprobe(&u, uprobe); | |
7b2d81d4 | 961 | |
2b144498 SD |
962 | if (uprobe->inode == inode) |
963 | close_node = n; | |
964 | ||
965 | if (!match) | |
966 | return close_node; | |
967 | ||
968 | if (match < 0) | |
969 | n = n->rb_left; | |
970 | else | |
971 | n = n->rb_right; | |
972 | } | |
7b2d81d4 | 973 | |
2b144498 SD |
974 | return close_node; |
975 | } | |
976 | ||
977 | /* | |
978 | * For a given inode, build a list of probes that need to be inserted. | |
979 | */ | |
980 | static void build_probe_list(struct inode *inode, struct list_head *head) | |
981 | { | |
982 | struct uprobe *uprobe; | |
2b144498 | 983 | unsigned long flags; |
7b2d81d4 | 984 | struct rb_node *n; |
2b144498 SD |
985 | |
986 | spin_lock_irqsave(&uprobes_treelock, flags); | |
7b2d81d4 | 987 | |
2b144498 | 988 | n = find_least_offset_node(inode); |
7b2d81d4 | 989 | |
2b144498 SD |
990 | for (; n; n = rb_next(n)) { |
991 | uprobe = rb_entry(n, struct uprobe, rb_node); | |
992 | if (uprobe->inode != inode) | |
993 | break; | |
994 | ||
995 | list_add(&uprobe->pending_list, head); | |
996 | atomic_inc(&uprobe->ref); | |
997 | } | |
7b2d81d4 | 998 | |
2b144498 SD |
999 | spin_unlock_irqrestore(&uprobes_treelock, flags); |
1000 | } | |
1001 | ||
1002 | /* | |
1003 | * Called from mmap_region. | |
1004 | * called with mm->mmap_sem acquired. | |
1005 | * | |
1006 | * Return -ve no if we fail to insert probes and we cannot | |
1007 | * bail-out. | |
7b2d81d4 IM |
1008 | * Return 0 otherwise. i.e: |
1009 | * | |
2b144498 SD |
1010 | * - successful insertion of probes |
1011 | * - (or) no possible probes to be inserted. | |
1012 | * - (or) insertion of probes failed but we can bail-out. | |
1013 | */ | |
7b2d81d4 | 1014 | int uprobe_mmap(struct vm_area_struct *vma) |
2b144498 SD |
1015 | { |
1016 | struct list_head tmp_list; | |
449d0d7c | 1017 | struct uprobe *uprobe; |
2b144498 | 1018 | struct inode *inode; |
682968e0 | 1019 | int ret, count; |
2b144498 SD |
1020 | |
1021 | if (!atomic_read(&uprobe_events) || !valid_vma(vma, true)) | |
7b2d81d4 | 1022 | return 0; |
2b144498 SD |
1023 | |
1024 | inode = vma->vm_file->f_mapping->host; | |
1025 | if (!inode) | |
7b2d81d4 | 1026 | return 0; |
2b144498 SD |
1027 | |
1028 | INIT_LIST_HEAD(&tmp_list); | |
1029 | mutex_lock(uprobes_mmap_hash(inode)); | |
1030 | build_probe_list(inode, &tmp_list); | |
7b2d81d4 IM |
1031 | |
1032 | ret = 0; | |
682968e0 | 1033 | count = 0; |
7b2d81d4 | 1034 | |
449d0d7c | 1035 | list_for_each_entry(uprobe, &tmp_list, pending_list) { |
2b144498 | 1036 | if (!ret) { |
816c03fb | 1037 | loff_t vaddr = vma_address(vma, uprobe->offset); |
682968e0 SD |
1038 | |
1039 | if (vaddr < vma->vm_start || vaddr >= vma->vm_end) { | |
1040 | put_uprobe(uprobe); | |
1041 | continue; | |
2b144498 | 1042 | } |
682968e0 SD |
1043 | |
1044 | ret = install_breakpoint(uprobe, vma->vm_mm, vma, vaddr); | |
c5784de2 PZ |
1045 | /* |
1046 | * We can race against uprobe_register(), see the | |
1047 | * comment near uprobe_hash(). | |
1048 | */ | |
682968e0 SD |
1049 | if (ret == -EEXIST) { |
1050 | ret = 0; | |
1051 | ||
1052 | if (!is_swbp_at_addr(vma->vm_mm, vaddr)) | |
1053 | continue; | |
1054 | ||
1055 | /* | |
1056 | * Unable to insert a breakpoint, but | |
1057 | * breakpoint lies underneath. Increment the | |
1058 | * probe count. | |
1059 | */ | |
1060 | atomic_inc(&vma->vm_mm->uprobes_state.count); | |
1061 | } | |
1062 | ||
1063 | if (!ret) | |
1064 | count++; | |
2b144498 SD |
1065 | } |
1066 | put_uprobe(uprobe); | |
1067 | } | |
1068 | ||
1069 | mutex_unlock(uprobes_mmap_hash(inode)); | |
1070 | ||
682968e0 SD |
1071 | if (ret) |
1072 | atomic_sub(count, &vma->vm_mm->uprobes_state.count); | |
1073 | ||
2b144498 SD |
1074 | return ret; |
1075 | } | |
1076 | ||
682968e0 SD |
1077 | /* |
1078 | * Called in context of a munmap of a vma. | |
1079 | */ | |
cbc91f71 | 1080 | void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end) |
682968e0 SD |
1081 | { |
1082 | struct list_head tmp_list; | |
449d0d7c | 1083 | struct uprobe *uprobe; |
682968e0 SD |
1084 | struct inode *inode; |
1085 | ||
1086 | if (!atomic_read(&uprobe_events) || !valid_vma(vma, false)) | |
1087 | return; | |
1088 | ||
1089 | if (!atomic_read(&vma->vm_mm->uprobes_state.count)) | |
1090 | return; | |
1091 | ||
1092 | inode = vma->vm_file->f_mapping->host; | |
1093 | if (!inode) | |
1094 | return; | |
1095 | ||
1096 | INIT_LIST_HEAD(&tmp_list); | |
1097 | mutex_lock(uprobes_mmap_hash(inode)); | |
1098 | build_probe_list(inode, &tmp_list); | |
1099 | ||
449d0d7c | 1100 | list_for_each_entry(uprobe, &tmp_list, pending_list) { |
816c03fb | 1101 | loff_t vaddr = vma_address(vma, uprobe->offset); |
682968e0 | 1102 | |
cbc91f71 | 1103 | if (vaddr >= start && vaddr < end) { |
682968e0 SD |
1104 | /* |
1105 | * An unregister could have removed the probe before | |
1106 | * unmap. So check before we decrement the count. | |
1107 | */ | |
1108 | if (is_swbp_at_addr(vma->vm_mm, vaddr) == 1) | |
1109 | atomic_dec(&vma->vm_mm->uprobes_state.count); | |
1110 | } | |
1111 | put_uprobe(uprobe); | |
1112 | } | |
1113 | mutex_unlock(uprobes_mmap_hash(inode)); | |
1114 | } | |
1115 | ||
d4b3b638 SD |
1116 | /* Slot allocation for XOL */ |
1117 | static int xol_add_vma(struct xol_area *area) | |
1118 | { | |
1119 | struct mm_struct *mm; | |
1120 | int ret; | |
1121 | ||
1122 | area->page = alloc_page(GFP_HIGHUSER); | |
1123 | if (!area->page) | |
1124 | return -ENOMEM; | |
1125 | ||
1126 | ret = -EALREADY; | |
1127 | mm = current->mm; | |
1128 | ||
1129 | down_write(&mm->mmap_sem); | |
1130 | if (mm->uprobes_state.xol_area) | |
1131 | goto fail; | |
1132 | ||
1133 | ret = -ENOMEM; | |
1134 | ||
1135 | /* Try to map as high as possible, this is only a hint. */ | |
1136 | area->vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, PAGE_SIZE, 0, 0); | |
1137 | if (area->vaddr & ~PAGE_MASK) { | |
1138 | ret = area->vaddr; | |
1139 | goto fail; | |
1140 | } | |
1141 | ||
1142 | ret = install_special_mapping(mm, area->vaddr, PAGE_SIZE, | |
1143 | VM_EXEC|VM_MAYEXEC|VM_DONTCOPY|VM_IO, &area->page); | |
1144 | if (ret) | |
1145 | goto fail; | |
1146 | ||
1147 | smp_wmb(); /* pairs with get_xol_area() */ | |
1148 | mm->uprobes_state.xol_area = area; | |
1149 | ret = 0; | |
1150 | ||
1151 | fail: | |
1152 | up_write(&mm->mmap_sem); | |
1153 | if (ret) | |
1154 | __free_page(area->page); | |
1155 | ||
1156 | return ret; | |
1157 | } | |
1158 | ||
1159 | static struct xol_area *get_xol_area(struct mm_struct *mm) | |
1160 | { | |
1161 | struct xol_area *area; | |
1162 | ||
1163 | area = mm->uprobes_state.xol_area; | |
1164 | smp_read_barrier_depends(); /* pairs with wmb in xol_add_vma() */ | |
1165 | ||
1166 | return area; | |
1167 | } | |
1168 | ||
1169 | /* | |
1170 | * xol_alloc_area - Allocate process's xol_area. | |
1171 | * This area will be used for storing instructions for execution out of | |
1172 | * line. | |
1173 | * | |
1174 | * Returns the allocated area or NULL. | |
1175 | */ | |
1176 | static struct xol_area *xol_alloc_area(void) | |
1177 | { | |
1178 | struct xol_area *area; | |
1179 | ||
1180 | area = kzalloc(sizeof(*area), GFP_KERNEL); | |
1181 | if (unlikely(!area)) | |
1182 | return NULL; | |
1183 | ||
1184 | area->bitmap = kzalloc(BITS_TO_LONGS(UINSNS_PER_PAGE) * sizeof(long), GFP_KERNEL); | |
1185 | ||
1186 | if (!area->bitmap) | |
1187 | goto fail; | |
1188 | ||
1189 | init_waitqueue_head(&area->wq); | |
1190 | if (!xol_add_vma(area)) | |
1191 | return area; | |
1192 | ||
1193 | fail: | |
1194 | kfree(area->bitmap); | |
1195 | kfree(area); | |
1196 | ||
1197 | return get_xol_area(current->mm); | |
1198 | } | |
1199 | ||
1200 | /* | |
1201 | * uprobe_clear_state - Free the area allocated for slots. | |
1202 | */ | |
1203 | void uprobe_clear_state(struct mm_struct *mm) | |
1204 | { | |
1205 | struct xol_area *area = mm->uprobes_state.xol_area; | |
1206 | ||
1207 | if (!area) | |
1208 | return; | |
1209 | ||
1210 | put_page(area->page); | |
1211 | kfree(area->bitmap); | |
1212 | kfree(area); | |
1213 | } | |
1214 | ||
1215 | /* | |
1216 | * uprobe_reset_state - Free the area allocated for slots. | |
1217 | */ | |
1218 | void uprobe_reset_state(struct mm_struct *mm) | |
1219 | { | |
1220 | mm->uprobes_state.xol_area = NULL; | |
682968e0 | 1221 | atomic_set(&mm->uprobes_state.count, 0); |
d4b3b638 SD |
1222 | } |
1223 | ||
1224 | /* | |
1225 | * - search for a free slot. | |
1226 | */ | |
1227 | static unsigned long xol_take_insn_slot(struct xol_area *area) | |
1228 | { | |
1229 | unsigned long slot_addr; | |
1230 | int slot_nr; | |
1231 | ||
1232 | do { | |
1233 | slot_nr = find_first_zero_bit(area->bitmap, UINSNS_PER_PAGE); | |
1234 | if (slot_nr < UINSNS_PER_PAGE) { | |
1235 | if (!test_and_set_bit(slot_nr, area->bitmap)) | |
1236 | break; | |
1237 | ||
1238 | slot_nr = UINSNS_PER_PAGE; | |
1239 | continue; | |
1240 | } | |
1241 | wait_event(area->wq, (atomic_read(&area->slot_count) < UINSNS_PER_PAGE)); | |
1242 | } while (slot_nr >= UINSNS_PER_PAGE); | |
1243 | ||
1244 | slot_addr = area->vaddr + (slot_nr * UPROBE_XOL_SLOT_BYTES); | |
1245 | atomic_inc(&area->slot_count); | |
1246 | ||
1247 | return slot_addr; | |
1248 | } | |
1249 | ||
1250 | /* | |
1251 | * xol_get_insn_slot - If was not allocated a slot, then | |
1252 | * allocate a slot. | |
1253 | * Returns the allocated slot address or 0. | |
1254 | */ | |
1255 | static unsigned long xol_get_insn_slot(struct uprobe *uprobe, unsigned long slot_addr) | |
1256 | { | |
1257 | struct xol_area *area; | |
1258 | unsigned long offset; | |
1259 | void *vaddr; | |
1260 | ||
1261 | area = get_xol_area(current->mm); | |
1262 | if (!area) { | |
1263 | area = xol_alloc_area(); | |
1264 | if (!area) | |
1265 | return 0; | |
1266 | } | |
1267 | current->utask->xol_vaddr = xol_take_insn_slot(area); | |
1268 | ||
1269 | /* | |
1270 | * Initialize the slot if xol_vaddr points to valid | |
1271 | * instruction slot. | |
1272 | */ | |
1273 | if (unlikely(!current->utask->xol_vaddr)) | |
1274 | return 0; | |
1275 | ||
1276 | current->utask->vaddr = slot_addr; | |
1277 | offset = current->utask->xol_vaddr & ~PAGE_MASK; | |
1278 | vaddr = kmap_atomic(area->page); | |
1279 | memcpy(vaddr + offset, uprobe->arch.insn, MAX_UINSN_BYTES); | |
1280 | kunmap_atomic(vaddr); | |
1281 | ||
1282 | return current->utask->xol_vaddr; | |
1283 | } | |
1284 | ||
1285 | /* | |
1286 | * xol_free_insn_slot - If slot was earlier allocated by | |
1287 | * @xol_get_insn_slot(), make the slot available for | |
1288 | * subsequent requests. | |
1289 | */ | |
1290 | static void xol_free_insn_slot(struct task_struct *tsk) | |
1291 | { | |
1292 | struct xol_area *area; | |
1293 | unsigned long vma_end; | |
1294 | unsigned long slot_addr; | |
1295 | ||
1296 | if (!tsk->mm || !tsk->mm->uprobes_state.xol_area || !tsk->utask) | |
1297 | return; | |
1298 | ||
1299 | slot_addr = tsk->utask->xol_vaddr; | |
1300 | ||
1301 | if (unlikely(!slot_addr || IS_ERR_VALUE(slot_addr))) | |
1302 | return; | |
1303 | ||
1304 | area = tsk->mm->uprobes_state.xol_area; | |
1305 | vma_end = area->vaddr + PAGE_SIZE; | |
1306 | if (area->vaddr <= slot_addr && slot_addr < vma_end) { | |
1307 | unsigned long offset; | |
1308 | int slot_nr; | |
1309 | ||
1310 | offset = slot_addr - area->vaddr; | |
1311 | slot_nr = offset / UPROBE_XOL_SLOT_BYTES; | |
1312 | if (slot_nr >= UINSNS_PER_PAGE) | |
1313 | return; | |
1314 | ||
1315 | clear_bit(slot_nr, area->bitmap); | |
1316 | atomic_dec(&area->slot_count); | |
1317 | if (waitqueue_active(&area->wq)) | |
1318 | wake_up(&area->wq); | |
1319 | ||
1320 | tsk->utask->xol_vaddr = 0; | |
1321 | } | |
1322 | } | |
1323 | ||
0326f5a9 SD |
1324 | /** |
1325 | * uprobe_get_swbp_addr - compute address of swbp given post-swbp regs | |
1326 | * @regs: Reflects the saved state of the task after it has hit a breakpoint | |
1327 | * instruction. | |
1328 | * Return the address of the breakpoint instruction. | |
1329 | */ | |
1330 | unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs) | |
1331 | { | |
1332 | return instruction_pointer(regs) - UPROBE_SWBP_INSN_SIZE; | |
1333 | } | |
1334 | ||
1335 | /* | |
1336 | * Called with no locks held. | |
1337 | * Called in context of a exiting or a exec-ing thread. | |
1338 | */ | |
1339 | void uprobe_free_utask(struct task_struct *t) | |
1340 | { | |
1341 | struct uprobe_task *utask = t->utask; | |
1342 | ||
0326f5a9 SD |
1343 | if (!utask) |
1344 | return; | |
1345 | ||
1346 | if (utask->active_uprobe) | |
1347 | put_uprobe(utask->active_uprobe); | |
1348 | ||
d4b3b638 | 1349 | xol_free_insn_slot(t); |
0326f5a9 SD |
1350 | kfree(utask); |
1351 | t->utask = NULL; | |
1352 | } | |
1353 | ||
1354 | /* | |
1355 | * Called in context of a new clone/fork from copy_process. | |
1356 | */ | |
1357 | void uprobe_copy_process(struct task_struct *t) | |
1358 | { | |
1359 | t->utask = NULL; | |
0326f5a9 SD |
1360 | } |
1361 | ||
1362 | /* | |
1363 | * Allocate a uprobe_task object for the task. | |
1364 | * Called when the thread hits a breakpoint for the first time. | |
1365 | * | |
1366 | * Returns: | |
1367 | * - pointer to new uprobe_task on success | |
1368 | * - NULL otherwise | |
1369 | */ | |
1370 | static struct uprobe_task *add_utask(void) | |
1371 | { | |
1372 | struct uprobe_task *utask; | |
1373 | ||
1374 | utask = kzalloc(sizeof *utask, GFP_KERNEL); | |
1375 | if (unlikely(!utask)) | |
1376 | return NULL; | |
1377 | ||
0326f5a9 SD |
1378 | current->utask = utask; |
1379 | return utask; | |
1380 | } | |
1381 | ||
1382 | /* Prepare to single-step probed instruction out of line. */ | |
1383 | static int | |
1384 | pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long vaddr) | |
1385 | { | |
d4b3b638 SD |
1386 | if (xol_get_insn_slot(uprobe, vaddr) && !arch_uprobe_pre_xol(&uprobe->arch, regs)) |
1387 | return 0; | |
1388 | ||
0326f5a9 SD |
1389 | return -EFAULT; |
1390 | } | |
1391 | ||
1392 | /* | |
1393 | * If we are singlestepping, then ensure this thread is not connected to | |
1394 | * non-fatal signals until completion of singlestep. When xol insn itself | |
1395 | * triggers the signal, restart the original insn even if the task is | |
1396 | * already SIGKILL'ed (since coredump should report the correct ip). This | |
1397 | * is even more important if the task has a handler for SIGSEGV/etc, The | |
1398 | * _same_ instruction should be repeated again after return from the signal | |
1399 | * handler, and SSTEP can never finish in this case. | |
1400 | */ | |
1401 | bool uprobe_deny_signal(void) | |
1402 | { | |
1403 | struct task_struct *t = current; | |
1404 | struct uprobe_task *utask = t->utask; | |
1405 | ||
1406 | if (likely(!utask || !utask->active_uprobe)) | |
1407 | return false; | |
1408 | ||
1409 | WARN_ON_ONCE(utask->state != UTASK_SSTEP); | |
1410 | ||
1411 | if (signal_pending(t)) { | |
1412 | spin_lock_irq(&t->sighand->siglock); | |
1413 | clear_tsk_thread_flag(t, TIF_SIGPENDING); | |
1414 | spin_unlock_irq(&t->sighand->siglock); | |
1415 | ||
1416 | if (__fatal_signal_pending(t) || arch_uprobe_xol_was_trapped(t)) { | |
1417 | utask->state = UTASK_SSTEP_TRAPPED; | |
1418 | set_tsk_thread_flag(t, TIF_UPROBE); | |
1419 | set_tsk_thread_flag(t, TIF_NOTIFY_RESUME); | |
1420 | } | |
1421 | } | |
1422 | ||
1423 | return true; | |
1424 | } | |
1425 | ||
1426 | /* | |
1427 | * Avoid singlestepping the original instruction if the original instruction | |
1428 | * is a NOP or can be emulated. | |
1429 | */ | |
1430 | static bool can_skip_sstep(struct uprobe *uprobe, struct pt_regs *regs) | |
1431 | { | |
1432 | if (arch_uprobe_skip_sstep(&uprobe->arch, regs)) | |
1433 | return true; | |
1434 | ||
1435 | uprobe->flags &= ~UPROBE_SKIP_SSTEP; | |
1436 | return false; | |
1437 | } | |
1438 | ||
d790d346 | 1439 | static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp) |
0326f5a9 | 1440 | { |
3a9ea052 ON |
1441 | struct mm_struct *mm = current->mm; |
1442 | struct uprobe *uprobe = NULL; | |
0326f5a9 | 1443 | struct vm_area_struct *vma; |
0326f5a9 | 1444 | |
0326f5a9 SD |
1445 | down_read(&mm->mmap_sem); |
1446 | vma = find_vma(mm, bp_vaddr); | |
3a9ea052 ON |
1447 | if (vma && vma->vm_start <= bp_vaddr) { |
1448 | if (valid_vma(vma, false)) { | |
1449 | struct inode *inode; | |
1450 | loff_t offset; | |
0326f5a9 | 1451 | |
3a9ea052 ON |
1452 | inode = vma->vm_file->f_mapping->host; |
1453 | offset = bp_vaddr - vma->vm_start; | |
1454 | offset += (vma->vm_pgoff << PAGE_SHIFT); | |
1455 | uprobe = find_uprobe(inode, offset); | |
1456 | } | |
d790d346 ON |
1457 | |
1458 | if (!uprobe) | |
1459 | *is_swbp = is_swbp_at_addr(mm, bp_vaddr); | |
1460 | } else { | |
1461 | *is_swbp = -EFAULT; | |
0326f5a9 | 1462 | } |
0326f5a9 SD |
1463 | up_read(&mm->mmap_sem); |
1464 | ||
3a9ea052 ON |
1465 | return uprobe; |
1466 | } | |
1467 | ||
1468 | /* | |
1469 | * Run handler and ask thread to singlestep. | |
1470 | * Ensure all non-fatal signals cannot interrupt thread while it singlesteps. | |
1471 | */ | |
1472 | static void handle_swbp(struct pt_regs *regs) | |
1473 | { | |
1474 | struct uprobe_task *utask; | |
1475 | struct uprobe *uprobe; | |
1476 | unsigned long bp_vaddr; | |
56bb4cf6 | 1477 | int uninitialized_var(is_swbp); |
3a9ea052 ON |
1478 | |
1479 | bp_vaddr = uprobe_get_swbp_addr(regs); | |
d790d346 | 1480 | uprobe = find_active_uprobe(bp_vaddr, &is_swbp); |
3a9ea052 | 1481 | |
0326f5a9 | 1482 | if (!uprobe) { |
56bb4cf6 ON |
1483 | if (is_swbp > 0) { |
1484 | /* No matching uprobe; signal SIGTRAP. */ | |
1485 | send_sig(SIGTRAP, current, 0); | |
1486 | } else { | |
1487 | /* | |
1488 | * Either we raced with uprobe_unregister() or we can't | |
1489 | * access this memory. The latter is only possible if | |
1490 | * another thread plays with our ->mm. In both cases | |
1491 | * we can simply restart. If this vma was unmapped we | |
1492 | * can pretend this insn was not executed yet and get | |
1493 | * the (correct) SIGSEGV after restart. | |
1494 | */ | |
1495 | instruction_pointer_set(regs, bp_vaddr); | |
1496 | } | |
0326f5a9 SD |
1497 | return; |
1498 | } | |
1499 | ||
1500 | utask = current->utask; | |
1501 | if (!utask) { | |
1502 | utask = add_utask(); | |
1503 | /* Cannot allocate; re-execute the instruction. */ | |
1504 | if (!utask) | |
1505 | goto cleanup_ret; | |
1506 | } | |
1507 | utask->active_uprobe = uprobe; | |
1508 | handler_chain(uprobe, regs); | |
1509 | if (uprobe->flags & UPROBE_SKIP_SSTEP && can_skip_sstep(uprobe, regs)) | |
1510 | goto cleanup_ret; | |
1511 | ||
1512 | utask->state = UTASK_SSTEP; | |
1513 | if (!pre_ssout(uprobe, regs, bp_vaddr)) { | |
1514 | user_enable_single_step(current); | |
1515 | return; | |
1516 | } | |
1517 | ||
1518 | cleanup_ret: | |
1519 | if (utask) { | |
1520 | utask->active_uprobe = NULL; | |
1521 | utask->state = UTASK_RUNNING; | |
1522 | } | |
1523 | if (uprobe) { | |
1524 | if (!(uprobe->flags & UPROBE_SKIP_SSTEP)) | |
1525 | ||
1526 | /* | |
1527 | * cannot singlestep; cannot skip instruction; | |
1528 | * re-execute the instruction. | |
1529 | */ | |
1530 | instruction_pointer_set(regs, bp_vaddr); | |
1531 | ||
1532 | put_uprobe(uprobe); | |
1533 | } | |
1534 | } | |
1535 | ||
1536 | /* | |
1537 | * Perform required fix-ups and disable singlestep. | |
1538 | * Allow pending signals to take effect. | |
1539 | */ | |
1540 | static void handle_singlestep(struct uprobe_task *utask, struct pt_regs *regs) | |
1541 | { | |
1542 | struct uprobe *uprobe; | |
1543 | ||
1544 | uprobe = utask->active_uprobe; | |
1545 | if (utask->state == UTASK_SSTEP_ACK) | |
1546 | arch_uprobe_post_xol(&uprobe->arch, regs); | |
1547 | else if (utask->state == UTASK_SSTEP_TRAPPED) | |
1548 | arch_uprobe_abort_xol(&uprobe->arch, regs); | |
1549 | else | |
1550 | WARN_ON_ONCE(1); | |
1551 | ||
1552 | put_uprobe(uprobe); | |
1553 | utask->active_uprobe = NULL; | |
1554 | utask->state = UTASK_RUNNING; | |
1555 | user_disable_single_step(current); | |
d4b3b638 | 1556 | xol_free_insn_slot(current); |
0326f5a9 SD |
1557 | |
1558 | spin_lock_irq(¤t->sighand->siglock); | |
1559 | recalc_sigpending(); /* see uprobe_deny_signal() */ | |
1560 | spin_unlock_irq(¤t->sighand->siglock); | |
1561 | } | |
1562 | ||
1563 | /* | |
1564 | * On breakpoint hit, breakpoint notifier sets the TIF_UPROBE flag. (and on | |
1565 | * subsequent probe hits on the thread sets the state to UTASK_BP_HIT) and | |
1566 | * allows the thread to return from interrupt. | |
1567 | * | |
1568 | * On singlestep exception, singlestep notifier sets the TIF_UPROBE flag and | |
1569 | * also sets the state to UTASK_SSTEP_ACK and allows the thread to return from | |
1570 | * interrupt. | |
1571 | * | |
1572 | * While returning to userspace, thread notices the TIF_UPROBE flag and calls | |
1573 | * uprobe_notify_resume(). | |
1574 | */ | |
1575 | void uprobe_notify_resume(struct pt_regs *regs) | |
1576 | { | |
1577 | struct uprobe_task *utask; | |
1578 | ||
1579 | utask = current->utask; | |
1580 | if (!utask || utask->state == UTASK_BP_HIT) | |
1581 | handle_swbp(regs); | |
1582 | else | |
1583 | handle_singlestep(utask, regs); | |
1584 | } | |
1585 | ||
1586 | /* | |
1587 | * uprobe_pre_sstep_notifier gets called from interrupt context as part of | |
1588 | * notifier mechanism. Set TIF_UPROBE flag and indicate breakpoint hit. | |
1589 | */ | |
1590 | int uprobe_pre_sstep_notifier(struct pt_regs *regs) | |
1591 | { | |
1592 | struct uprobe_task *utask; | |
1593 | ||
682968e0 SD |
1594 | if (!current->mm || !atomic_read(¤t->mm->uprobes_state.count)) |
1595 | /* task is currently not uprobed */ | |
0326f5a9 SD |
1596 | return 0; |
1597 | ||
1598 | utask = current->utask; | |
1599 | if (utask) | |
1600 | utask->state = UTASK_BP_HIT; | |
1601 | ||
1602 | set_thread_flag(TIF_UPROBE); | |
0326f5a9 SD |
1603 | |
1604 | return 1; | |
1605 | } | |
1606 | ||
1607 | /* | |
1608 | * uprobe_post_sstep_notifier gets called in interrupt context as part of notifier | |
1609 | * mechanism. Set TIF_UPROBE flag and indicate completion of singlestep. | |
1610 | */ | |
1611 | int uprobe_post_sstep_notifier(struct pt_regs *regs) | |
1612 | { | |
1613 | struct uprobe_task *utask = current->utask; | |
1614 | ||
1615 | if (!current->mm || !utask || !utask->active_uprobe) | |
1616 | /* task is currently not uprobed */ | |
1617 | return 0; | |
1618 | ||
1619 | utask->state = UTASK_SSTEP_ACK; | |
1620 | set_thread_flag(TIF_UPROBE); | |
1621 | return 1; | |
1622 | } | |
1623 | ||
1624 | static struct notifier_block uprobe_exception_nb = { | |
1625 | .notifier_call = arch_uprobe_exception_notify, | |
1626 | .priority = INT_MAX-1, /* notified after kprobes, kgdb */ | |
1627 | }; | |
1628 | ||
2b144498 SD |
1629 | static int __init init_uprobes(void) |
1630 | { | |
1631 | int i; | |
1632 | ||
1633 | for (i = 0; i < UPROBES_HASH_SZ; i++) { | |
1634 | mutex_init(&uprobes_mutex[i]); | |
1635 | mutex_init(&uprobes_mmap_mutex[i]); | |
1636 | } | |
0326f5a9 SD |
1637 | |
1638 | return register_die_notifier(&uprobe_exception_nb); | |
2b144498 | 1639 | } |
0326f5a9 | 1640 | module_init(init_uprobes); |
2b144498 SD |
1641 | |
1642 | static void __exit exit_uprobes(void) | |
1643 | { | |
1644 | } | |
2b144498 | 1645 | module_exit(exit_uprobes); |