]>
Commit | Line | Data |
---|---|---|
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; | |
209 | struct address_space *mapping; | |
210 | void *vaddr_old, *vaddr_new; | |
211 | struct vm_area_struct *vma; | |
3ff54efd | 212 | struct uprobe *uprobe; |
2b144498 | 213 | int ret; |
5323ce71 | 214 | retry: |
2b144498 SD |
215 | /* Read the page with vaddr into memory */ |
216 | ret = get_user_pages(NULL, mm, vaddr, 1, 0, 0, &old_page, &vma); | |
217 | if (ret <= 0) | |
218 | return ret; | |
7b2d81d4 | 219 | |
2b144498 SD |
220 | ret = -EINVAL; |
221 | ||
222 | /* | |
223 | * We are interested in text pages only. Our pages of interest | |
224 | * should be mapped for read and execute only. We desist from | |
225 | * adding probes in write mapped pages since the breakpoints | |
226 | * might end up in the file copy. | |
227 | */ | |
5cb4ac3a | 228 | if (!valid_vma(vma, is_swbp_insn(&opcode))) |
2b144498 SD |
229 | goto put_out; |
230 | ||
3ff54efd | 231 | uprobe = container_of(auprobe, struct uprobe, arch); |
2b144498 SD |
232 | mapping = uprobe->inode->i_mapping; |
233 | if (mapping != vma->vm_file->f_mapping) | |
234 | goto put_out; | |
235 | ||
2b144498 SD |
236 | ret = -ENOMEM; |
237 | new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr); | |
238 | if (!new_page) | |
239 | goto put_out; | |
240 | ||
241 | __SetPageUptodate(new_page); | |
242 | ||
243 | /* | |
244 | * lock page will serialize against do_wp_page()'s | |
245 | * PageAnon() handling | |
246 | */ | |
247 | lock_page(old_page); | |
248 | /* copy the page now that we've got it stable */ | |
249 | vaddr_old = kmap_atomic(old_page); | |
250 | vaddr_new = kmap_atomic(new_page); | |
251 | ||
252 | memcpy(vaddr_new, vaddr_old, PAGE_SIZE); | |
d9c4a30e | 253 | memcpy(vaddr_new + (vaddr & ~PAGE_MASK), &opcode, UPROBE_SWBP_INSN_SIZE); |
2b144498 SD |
254 | |
255 | kunmap_atomic(vaddr_new); | |
256 | kunmap_atomic(vaddr_old); | |
257 | ||
258 | ret = anon_vma_prepare(vma); | |
259 | if (ret) | |
260 | goto unlock_out; | |
261 | ||
262 | lock_page(new_page); | |
263 | ret = __replace_page(vma, old_page, new_page); | |
264 | unlock_page(new_page); | |
265 | ||
266 | unlock_out: | |
267 | unlock_page(old_page); | |
268 | page_cache_release(new_page); | |
269 | ||
270 | put_out: | |
7b2d81d4 IM |
271 | put_page(old_page); |
272 | ||
5323ce71 ON |
273 | if (unlikely(ret == -EAGAIN)) |
274 | goto retry; | |
2b144498 SD |
275 | return ret; |
276 | } | |
277 | ||
278 | /** | |
279 | * read_opcode - read the opcode at a given virtual address. | |
280 | * @mm: the probed process address space. | |
281 | * @vaddr: the virtual address to read the opcode. | |
282 | * @opcode: location to store the read opcode. | |
283 | * | |
284 | * Called with mm->mmap_sem held (for read and with a reference to | |
285 | * mm. | |
286 | * | |
287 | * For mm @mm, read the opcode at @vaddr and store it in @opcode. | |
288 | * Return 0 (success) or a negative errno. | |
289 | */ | |
7b2d81d4 | 290 | static int read_opcode(struct mm_struct *mm, unsigned long vaddr, uprobe_opcode_t *opcode) |
2b144498 SD |
291 | { |
292 | struct page *page; | |
293 | void *vaddr_new; | |
294 | int ret; | |
295 | ||
a3d7bb47 | 296 | ret = get_user_pages(NULL, mm, vaddr, 1, 0, 1, &page, NULL); |
2b144498 SD |
297 | if (ret <= 0) |
298 | return ret; | |
299 | ||
300 | lock_page(page); | |
301 | vaddr_new = kmap_atomic(page); | |
302 | vaddr &= ~PAGE_MASK; | |
5cb4ac3a | 303 | memcpy(opcode, vaddr_new + vaddr, UPROBE_SWBP_INSN_SIZE); |
2b144498 SD |
304 | kunmap_atomic(vaddr_new); |
305 | unlock_page(page); | |
7b2d81d4 IM |
306 | |
307 | put_page(page); | |
308 | ||
2b144498 SD |
309 | return 0; |
310 | } | |
311 | ||
5cb4ac3a | 312 | static int is_swbp_at_addr(struct mm_struct *mm, unsigned long vaddr) |
2b144498 SD |
313 | { |
314 | uprobe_opcode_t opcode; | |
7b2d81d4 | 315 | int result; |
2b144498 | 316 | |
c00b2750 ON |
317 | if (current->mm == mm) { |
318 | pagefault_disable(); | |
319 | result = __copy_from_user_inatomic(&opcode, (void __user*)vaddr, | |
320 | sizeof(opcode)); | |
321 | pagefault_enable(); | |
322 | ||
323 | if (likely(result == 0)) | |
324 | goto out; | |
325 | } | |
326 | ||
7b2d81d4 | 327 | result = read_opcode(mm, vaddr, &opcode); |
2b144498 SD |
328 | if (result) |
329 | return result; | |
c00b2750 | 330 | out: |
5cb4ac3a | 331 | if (is_swbp_insn(&opcode)) |
2b144498 SD |
332 | return 1; |
333 | ||
334 | return 0; | |
335 | } | |
336 | ||
337 | /** | |
5cb4ac3a | 338 | * set_swbp - store breakpoint at a given address. |
e3343e6a | 339 | * @auprobe: arch specific probepoint information. |
2b144498 | 340 | * @mm: the probed process address space. |
2b144498 SD |
341 | * @vaddr: the virtual address to insert the opcode. |
342 | * | |
343 | * For mm @mm, store the breakpoint instruction at @vaddr. | |
344 | * Return 0 (success) or a negative errno. | |
345 | */ | |
5cb4ac3a | 346 | int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) |
2b144498 | 347 | { |
7b2d81d4 | 348 | int result; |
c5784de2 PZ |
349 | /* |
350 | * See the comment near uprobes_hash(). | |
351 | */ | |
5cb4ac3a | 352 | result = is_swbp_at_addr(mm, vaddr); |
2b144498 SD |
353 | if (result == 1) |
354 | return -EEXIST; | |
355 | ||
356 | if (result) | |
357 | return result; | |
358 | ||
5cb4ac3a | 359 | return write_opcode(auprobe, mm, vaddr, UPROBE_SWBP_INSN); |
2b144498 SD |
360 | } |
361 | ||
362 | /** | |
363 | * set_orig_insn - Restore the original instruction. | |
364 | * @mm: the probed process address space. | |
e3343e6a | 365 | * @auprobe: arch specific probepoint information. |
2b144498 SD |
366 | * @vaddr: the virtual address to insert the opcode. |
367 | * @verify: if true, verify existance of breakpoint instruction. | |
368 | * | |
369 | * For mm @mm, restore the original opcode (opcode) at @vaddr. | |
370 | * Return 0 (success) or a negative errno. | |
371 | */ | |
7b2d81d4 | 372 | int __weak |
e3343e6a | 373 | set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr, bool verify) |
2b144498 SD |
374 | { |
375 | if (verify) { | |
7b2d81d4 | 376 | int result; |
2b144498 | 377 | |
5cb4ac3a | 378 | result = is_swbp_at_addr(mm, vaddr); |
2b144498 SD |
379 | if (!result) |
380 | return -EINVAL; | |
381 | ||
382 | if (result != 1) | |
383 | return result; | |
384 | } | |
e3343e6a | 385 | return write_opcode(auprobe, mm, vaddr, *(uprobe_opcode_t *)auprobe->insn); |
2b144498 SD |
386 | } |
387 | ||
388 | static int match_uprobe(struct uprobe *l, struct uprobe *r) | |
389 | { | |
390 | if (l->inode < r->inode) | |
391 | return -1; | |
7b2d81d4 | 392 | |
2b144498 SD |
393 | if (l->inode > r->inode) |
394 | return 1; | |
2b144498 | 395 | |
7b2d81d4 IM |
396 | if (l->offset < r->offset) |
397 | return -1; | |
398 | ||
399 | if (l->offset > r->offset) | |
400 | return 1; | |
2b144498 SD |
401 | |
402 | return 0; | |
403 | } | |
404 | ||
405 | static struct uprobe *__find_uprobe(struct inode *inode, loff_t offset) | |
406 | { | |
407 | struct uprobe u = { .inode = inode, .offset = offset }; | |
408 | struct rb_node *n = uprobes_tree.rb_node; | |
409 | struct uprobe *uprobe; | |
410 | int match; | |
411 | ||
412 | while (n) { | |
413 | uprobe = rb_entry(n, struct uprobe, rb_node); | |
414 | match = match_uprobe(&u, uprobe); | |
415 | if (!match) { | |
416 | atomic_inc(&uprobe->ref); | |
417 | return uprobe; | |
418 | } | |
7b2d81d4 | 419 | |
2b144498 SD |
420 | if (match < 0) |
421 | n = n->rb_left; | |
422 | else | |
423 | n = n->rb_right; | |
424 | } | |
425 | return NULL; | |
426 | } | |
427 | ||
428 | /* | |
429 | * Find a uprobe corresponding to a given inode:offset | |
430 | * Acquires uprobes_treelock | |
431 | */ | |
432 | static struct uprobe *find_uprobe(struct inode *inode, loff_t offset) | |
433 | { | |
434 | struct uprobe *uprobe; | |
435 | unsigned long flags; | |
436 | ||
437 | spin_lock_irqsave(&uprobes_treelock, flags); | |
438 | uprobe = __find_uprobe(inode, offset); | |
439 | spin_unlock_irqrestore(&uprobes_treelock, flags); | |
7b2d81d4 | 440 | |
2b144498 SD |
441 | return uprobe; |
442 | } | |
443 | ||
444 | static struct uprobe *__insert_uprobe(struct uprobe *uprobe) | |
445 | { | |
446 | struct rb_node **p = &uprobes_tree.rb_node; | |
447 | struct rb_node *parent = NULL; | |
448 | struct uprobe *u; | |
449 | int match; | |
450 | ||
451 | while (*p) { | |
452 | parent = *p; | |
453 | u = rb_entry(parent, struct uprobe, rb_node); | |
454 | match = match_uprobe(uprobe, u); | |
455 | if (!match) { | |
456 | atomic_inc(&u->ref); | |
457 | return u; | |
458 | } | |
459 | ||
460 | if (match < 0) | |
461 | p = &parent->rb_left; | |
462 | else | |
463 | p = &parent->rb_right; | |
464 | ||
465 | } | |
7b2d81d4 | 466 | |
2b144498 SD |
467 | u = NULL; |
468 | rb_link_node(&uprobe->rb_node, parent, p); | |
469 | rb_insert_color(&uprobe->rb_node, &uprobes_tree); | |
470 | /* get access + creation ref */ | |
471 | atomic_set(&uprobe->ref, 2); | |
7b2d81d4 | 472 | |
2b144498 SD |
473 | return u; |
474 | } | |
475 | ||
476 | /* | |
7b2d81d4 | 477 | * Acquire uprobes_treelock. |
2b144498 SD |
478 | * Matching uprobe already exists in rbtree; |
479 | * increment (access refcount) and return the matching uprobe. | |
480 | * | |
481 | * No matching uprobe; insert the uprobe in rb_tree; | |
482 | * get a double refcount (access + creation) and return NULL. | |
483 | */ | |
484 | static struct uprobe *insert_uprobe(struct uprobe *uprobe) | |
485 | { | |
486 | unsigned long flags; | |
487 | struct uprobe *u; | |
488 | ||
489 | spin_lock_irqsave(&uprobes_treelock, flags); | |
490 | u = __insert_uprobe(uprobe); | |
491 | spin_unlock_irqrestore(&uprobes_treelock, flags); | |
7b2d81d4 | 492 | |
0326f5a9 SD |
493 | /* For now assume that the instruction need not be single-stepped */ |
494 | uprobe->flags |= UPROBE_SKIP_SSTEP; | |
495 | ||
2b144498 SD |
496 | return u; |
497 | } | |
498 | ||
499 | static void put_uprobe(struct uprobe *uprobe) | |
500 | { | |
501 | if (atomic_dec_and_test(&uprobe->ref)) | |
502 | kfree(uprobe); | |
503 | } | |
504 | ||
505 | static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset) | |
506 | { | |
507 | struct uprobe *uprobe, *cur_uprobe; | |
508 | ||
509 | uprobe = kzalloc(sizeof(struct uprobe), GFP_KERNEL); | |
510 | if (!uprobe) | |
511 | return NULL; | |
512 | ||
513 | uprobe->inode = igrab(inode); | |
514 | uprobe->offset = offset; | |
515 | init_rwsem(&uprobe->consumer_rwsem); | |
2b144498 SD |
516 | |
517 | /* add to uprobes_tree, sorted on inode:offset */ | |
518 | cur_uprobe = insert_uprobe(uprobe); | |
519 | ||
520 | /* a uprobe exists for this inode:offset combination */ | |
521 | if (cur_uprobe) { | |
522 | kfree(uprobe); | |
523 | uprobe = cur_uprobe; | |
524 | iput(inode); | |
7b2d81d4 | 525 | } else { |
2b144498 | 526 | atomic_inc(&uprobe_events); |
7b2d81d4 IM |
527 | } |
528 | ||
2b144498 SD |
529 | return uprobe; |
530 | } | |
531 | ||
0326f5a9 SD |
532 | static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs) |
533 | { | |
534 | struct uprobe_consumer *uc; | |
535 | ||
536 | if (!(uprobe->flags & UPROBE_RUN_HANDLER)) | |
537 | return; | |
538 | ||
539 | down_read(&uprobe->consumer_rwsem); | |
540 | for (uc = uprobe->consumers; uc; uc = uc->next) { | |
541 | if (!uc->filter || uc->filter(uc, current)) | |
542 | uc->handler(uc, regs); | |
543 | } | |
544 | up_read(&uprobe->consumer_rwsem); | |
545 | } | |
546 | ||
2b144498 | 547 | /* Returns the previous consumer */ |
7b2d81d4 | 548 | static struct uprobe_consumer * |
e3343e6a | 549 | consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc) |
2b144498 SD |
550 | { |
551 | down_write(&uprobe->consumer_rwsem); | |
e3343e6a SD |
552 | uc->next = uprobe->consumers; |
553 | uprobe->consumers = uc; | |
2b144498 | 554 | up_write(&uprobe->consumer_rwsem); |
7b2d81d4 | 555 | |
e3343e6a | 556 | return uc->next; |
2b144498 SD |
557 | } |
558 | ||
559 | /* | |
e3343e6a SD |
560 | * For uprobe @uprobe, delete the consumer @uc. |
561 | * Return true if the @uc is deleted successfully | |
2b144498 SD |
562 | * or return false. |
563 | */ | |
e3343e6a | 564 | static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *uc) |
2b144498 SD |
565 | { |
566 | struct uprobe_consumer **con; | |
567 | bool ret = false; | |
568 | ||
569 | down_write(&uprobe->consumer_rwsem); | |
570 | for (con = &uprobe->consumers; *con; con = &(*con)->next) { | |
e3343e6a SD |
571 | if (*con == uc) { |
572 | *con = uc->next; | |
2b144498 SD |
573 | ret = true; |
574 | break; | |
575 | } | |
576 | } | |
577 | up_write(&uprobe->consumer_rwsem); | |
7b2d81d4 | 578 | |
2b144498 SD |
579 | return ret; |
580 | } | |
581 | ||
e3343e6a | 582 | static int |
d436615e | 583 | __copy_insn(struct address_space *mapping, struct file *filp, char *insn, |
2b144498 SD |
584 | unsigned long nbytes, unsigned long offset) |
585 | { | |
2b144498 SD |
586 | struct page *page; |
587 | void *vaddr; | |
588 | unsigned long off1; | |
589 | unsigned long idx; | |
590 | ||
591 | if (!filp) | |
592 | return -EINVAL; | |
593 | ||
cc359d18 ON |
594 | if (!mapping->a_ops->readpage) |
595 | return -EIO; | |
596 | ||
2b144498 SD |
597 | idx = (unsigned long)(offset >> PAGE_CACHE_SHIFT); |
598 | off1 = offset &= ~PAGE_MASK; | |
599 | ||
600 | /* | |
601 | * Ensure that the page that has the original instruction is | |
602 | * populated and in page-cache. | |
603 | */ | |
604 | page = read_mapping_page(mapping, idx, filp); | |
605 | if (IS_ERR(page)) | |
606 | return PTR_ERR(page); | |
607 | ||
608 | vaddr = kmap_atomic(page); | |
609 | memcpy(insn, vaddr + off1, nbytes); | |
610 | kunmap_atomic(vaddr); | |
611 | page_cache_release(page); | |
7b2d81d4 | 612 | |
2b144498 SD |
613 | return 0; |
614 | } | |
615 | ||
d436615e | 616 | static int copy_insn(struct uprobe *uprobe, struct file *filp) |
2b144498 SD |
617 | { |
618 | struct address_space *mapping; | |
2b144498 | 619 | unsigned long nbytes; |
7b2d81d4 | 620 | int bytes; |
2b144498 | 621 | |
d436615e | 622 | nbytes = PAGE_SIZE - (uprobe->offset & ~PAGE_MASK); |
2b144498 SD |
623 | mapping = uprobe->inode->i_mapping; |
624 | ||
625 | /* Instruction at end of binary; copy only available bytes */ | |
626 | if (uprobe->offset + MAX_UINSN_BYTES > uprobe->inode->i_size) | |
627 | bytes = uprobe->inode->i_size - uprobe->offset; | |
628 | else | |
629 | bytes = MAX_UINSN_BYTES; | |
630 | ||
631 | /* Instruction at the page-boundary; copy bytes in second page */ | |
632 | if (nbytes < bytes) { | |
fc36f595 ON |
633 | int err = __copy_insn(mapping, filp, uprobe->arch.insn + nbytes, |
634 | bytes - nbytes, uprobe->offset + nbytes); | |
635 | if (err) | |
636 | return err; | |
2b144498 SD |
637 | bytes = nbytes; |
638 | } | |
d436615e | 639 | return __copy_insn(mapping, filp, uprobe->arch.insn, bytes, uprobe->offset); |
2b144498 SD |
640 | } |
641 | ||
682968e0 SD |
642 | /* |
643 | * How mm->uprobes_state.count gets updated | |
644 | * uprobe_mmap() increments the count if | |
645 | * - it successfully adds a breakpoint. | |
646 | * - it cannot add a breakpoint, but sees that there is a underlying | |
647 | * breakpoint (via a is_swbp_at_addr()). | |
648 | * | |
649 | * uprobe_munmap() decrements the count if | |
650 | * - it sees a underlying breakpoint, (via is_swbp_at_addr) | |
651 | * (Subsequent uprobe_unregister wouldnt find the breakpoint | |
652 | * unless a uprobe_mmap kicks in, since the old vma would be | |
653 | * dropped just after uprobe_munmap.) | |
654 | * | |
655 | * uprobe_register increments the count if: | |
656 | * - it successfully adds a breakpoint. | |
657 | * | |
658 | * uprobe_unregister decrements the count if: | |
659 | * - it sees a underlying breakpoint and removes successfully. | |
660 | * (via is_swbp_at_addr) | |
661 | * (Subsequent uprobe_munmap wouldnt find the breakpoint | |
662 | * since there is no underlying breakpoint after the | |
663 | * breakpoint removal.) | |
664 | */ | |
e3343e6a SD |
665 | static int |
666 | install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, | |
816c03fb | 667 | struct vm_area_struct *vma, unsigned long vaddr) |
2b144498 | 668 | { |
2b144498 SD |
669 | int ret; |
670 | ||
671 | /* | |
672 | * If probe is being deleted, unregister thread could be done with | |
673 | * the vma-rmap-walk through. Adding a probe now can be fatal since | |
674 | * nobody will be able to cleanup. Also we could be from fork or | |
675 | * mremap path, where the probe might have already been inserted. | |
676 | * Hence behave as if probe already existed. | |
677 | */ | |
678 | if (!uprobe->consumers) | |
679 | return -EEXIST; | |
680 | ||
900771a4 | 681 | if (!(uprobe->flags & UPROBE_COPY_INSN)) { |
d436615e | 682 | ret = copy_insn(uprobe, vma->vm_file); |
2b144498 SD |
683 | if (ret) |
684 | return ret; | |
685 | ||
5cb4ac3a | 686 | if (is_swbp_insn((uprobe_opcode_t *)uprobe->arch.insn)) |
c1914a09 | 687 | return -ENOTSUPP; |
2b144498 | 688 | |
816c03fb | 689 | ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, vaddr); |
2b144498 SD |
690 | if (ret) |
691 | return ret; | |
692 | ||
d9c4a30e ON |
693 | /* write_opcode() assumes we don't cross page boundary */ |
694 | BUG_ON((uprobe->offset & ~PAGE_MASK) + | |
695 | UPROBE_SWBP_INSN_SIZE > PAGE_SIZE); | |
696 | ||
900771a4 | 697 | uprobe->flags |= UPROBE_COPY_INSN; |
2b144498 | 698 | } |
682968e0 SD |
699 | |
700 | /* | |
701 | * Ideally, should be updating the probe count after the breakpoint | |
702 | * has been successfully inserted. However a thread could hit the | |
703 | * breakpoint we just inserted even before the probe count is | |
704 | * incremented. If this is the first breakpoint placed, breakpoint | |
705 | * notifier might ignore uprobes and pass the trap to the thread. | |
706 | * Hence increment before and decrement on failure. | |
707 | */ | |
708 | atomic_inc(&mm->uprobes_state.count); | |
816c03fb | 709 | ret = set_swbp(&uprobe->arch, mm, vaddr); |
682968e0 SD |
710 | if (ret) |
711 | atomic_dec(&mm->uprobes_state.count); | |
2b144498 SD |
712 | |
713 | return ret; | |
714 | } | |
715 | ||
e3343e6a | 716 | static void |
816c03fb | 717 | remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, unsigned long vaddr) |
2b144498 | 718 | { |
816c03fb | 719 | if (!set_orig_insn(&uprobe->arch, mm, vaddr, true)) |
682968e0 | 720 | atomic_dec(&mm->uprobes_state.count); |
2b144498 SD |
721 | } |
722 | ||
0326f5a9 | 723 | /* |
778b032d ON |
724 | * There could be threads that have already hit the breakpoint. They |
725 | * will recheck the current insn and restart if find_uprobe() fails. | |
726 | * See find_active_uprobe(). | |
0326f5a9 | 727 | */ |
2b144498 SD |
728 | static void delete_uprobe(struct uprobe *uprobe) |
729 | { | |
730 | unsigned long flags; | |
731 | ||
732 | spin_lock_irqsave(&uprobes_treelock, flags); | |
733 | rb_erase(&uprobe->rb_node, &uprobes_tree); | |
734 | spin_unlock_irqrestore(&uprobes_treelock, flags); | |
735 | iput(uprobe->inode); | |
736 | put_uprobe(uprobe); | |
737 | atomic_dec(&uprobe_events); | |
738 | } | |
739 | ||
26872090 ON |
740 | struct map_info { |
741 | struct map_info *next; | |
742 | struct mm_struct *mm; | |
816c03fb | 743 | unsigned long vaddr; |
26872090 ON |
744 | }; |
745 | ||
746 | static inline struct map_info *free_map_info(struct map_info *info) | |
2b144498 | 747 | { |
26872090 ON |
748 | struct map_info *next = info->next; |
749 | kfree(info); | |
750 | return next; | |
751 | } | |
752 | ||
753 | static struct map_info * | |
754 | build_map_info(struct address_space *mapping, loff_t offset, bool is_register) | |
755 | { | |
756 | unsigned long pgoff = offset >> PAGE_SHIFT; | |
2b144498 SD |
757 | struct prio_tree_iter iter; |
758 | struct vm_area_struct *vma; | |
26872090 ON |
759 | struct map_info *curr = NULL; |
760 | struct map_info *prev = NULL; | |
761 | struct map_info *info; | |
762 | int more = 0; | |
2b144498 | 763 | |
26872090 ON |
764 | again: |
765 | mutex_lock(&mapping->i_mmap_mutex); | |
2b144498 SD |
766 | vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) { |
767 | if (!valid_vma(vma, is_register)) | |
768 | continue; | |
769 | ||
7a5bfb66 ON |
770 | if (!prev && !more) { |
771 | /* | |
772 | * Needs GFP_NOWAIT to avoid i_mmap_mutex recursion through | |
773 | * reclaim. This is optimistic, no harm done if it fails. | |
774 | */ | |
775 | prev = kmalloc(sizeof(struct map_info), | |
776 | GFP_NOWAIT | __GFP_NOMEMALLOC | __GFP_NOWARN); | |
777 | if (prev) | |
778 | prev->next = NULL; | |
779 | } | |
26872090 ON |
780 | if (!prev) { |
781 | more++; | |
782 | continue; | |
2b144498 | 783 | } |
2b144498 | 784 | |
26872090 ON |
785 | if (!atomic_inc_not_zero(&vma->vm_mm->mm_users)) |
786 | continue; | |
7b2d81d4 | 787 | |
26872090 ON |
788 | info = prev; |
789 | prev = prev->next; | |
790 | info->next = curr; | |
791 | curr = info; | |
2b144498 | 792 | |
26872090 ON |
793 | info->mm = vma->vm_mm; |
794 | info->vaddr = vma_address(vma, offset); | |
795 | } | |
2b144498 SD |
796 | mutex_unlock(&mapping->i_mmap_mutex); |
797 | ||
26872090 ON |
798 | if (!more) |
799 | goto out; | |
800 | ||
801 | prev = curr; | |
802 | while (curr) { | |
803 | mmput(curr->mm); | |
804 | curr = curr->next; | |
805 | } | |
7b2d81d4 | 806 | |
26872090 ON |
807 | do { |
808 | info = kmalloc(sizeof(struct map_info), GFP_KERNEL); | |
809 | if (!info) { | |
810 | curr = ERR_PTR(-ENOMEM); | |
811 | goto out; | |
812 | } | |
813 | info->next = prev; | |
814 | prev = info; | |
815 | } while (--more); | |
816 | ||
817 | goto again; | |
818 | out: | |
819 | while (prev) | |
820 | prev = free_map_info(prev); | |
821 | return curr; | |
2b144498 SD |
822 | } |
823 | ||
824 | static int register_for_each_vma(struct uprobe *uprobe, bool is_register) | |
825 | { | |
26872090 ON |
826 | struct map_info *info; |
827 | int err = 0; | |
2b144498 | 828 | |
26872090 ON |
829 | info = build_map_info(uprobe->inode->i_mapping, |
830 | uprobe->offset, is_register); | |
831 | if (IS_ERR(info)) | |
832 | return PTR_ERR(info); | |
7b2d81d4 | 833 | |
26872090 ON |
834 | while (info) { |
835 | struct mm_struct *mm = info->mm; | |
836 | struct vm_area_struct *vma; | |
7b2d81d4 | 837 | |
26872090 ON |
838 | if (err) |
839 | goto free; | |
7b2d81d4 | 840 | |
77fc4af1 | 841 | down_write(&mm->mmap_sem); |
26872090 ON |
842 | vma = find_vma(mm, (unsigned long)info->vaddr); |
843 | if (!vma || !valid_vma(vma, is_register)) | |
844 | goto unlock; | |
845 | ||
2b144498 | 846 | if (vma->vm_file->f_mapping->host != uprobe->inode || |
816c03fb | 847 | vma_address(vma, uprobe->offset) != info->vaddr) |
26872090 | 848 | goto unlock; |
2b144498 | 849 | |
2b144498 | 850 | if (is_register) { |
26872090 | 851 | err = install_breakpoint(uprobe, mm, vma, info->vaddr); |
c5784de2 PZ |
852 | /* |
853 | * We can race against uprobe_mmap(), see the | |
854 | * comment near uprobe_hash(). | |
855 | */ | |
26872090 ON |
856 | if (err == -EEXIST) |
857 | err = 0; | |
858 | } else { | |
859 | remove_breakpoint(uprobe, mm, info->vaddr); | |
2b144498 | 860 | } |
26872090 ON |
861 | unlock: |
862 | up_write(&mm->mmap_sem); | |
863 | free: | |
864 | mmput(mm); | |
865 | info = free_map_info(info); | |
2b144498 | 866 | } |
7b2d81d4 | 867 | |
26872090 | 868 | return err; |
2b144498 SD |
869 | } |
870 | ||
7b2d81d4 | 871 | static int __uprobe_register(struct uprobe *uprobe) |
2b144498 SD |
872 | { |
873 | return register_for_each_vma(uprobe, true); | |
874 | } | |
875 | ||
7b2d81d4 | 876 | static void __uprobe_unregister(struct uprobe *uprobe) |
2b144498 SD |
877 | { |
878 | if (!register_for_each_vma(uprobe, false)) | |
879 | delete_uprobe(uprobe); | |
880 | ||
881 | /* TODO : cant unregister? schedule a worker thread */ | |
882 | } | |
883 | ||
884 | /* | |
7b2d81d4 | 885 | * uprobe_register - register a probe |
2b144498 SD |
886 | * @inode: the file in which the probe has to be placed. |
887 | * @offset: offset from the start of the file. | |
e3343e6a | 888 | * @uc: information on howto handle the probe.. |
2b144498 | 889 | * |
7b2d81d4 | 890 | * Apart from the access refcount, uprobe_register() takes a creation |
2b144498 SD |
891 | * refcount (thro alloc_uprobe) if and only if this @uprobe is getting |
892 | * inserted into the rbtree (i.e first consumer for a @inode:@offset | |
7b2d81d4 | 893 | * tuple). Creation refcount stops uprobe_unregister from freeing the |
2b144498 | 894 | * @uprobe even before the register operation is complete. Creation |
e3343e6a | 895 | * refcount is released when the last @uc for the @uprobe |
2b144498 SD |
896 | * unregisters. |
897 | * | |
898 | * Return errno if it cannot successully install probes | |
899 | * else return 0 (success) | |
900 | */ | |
e3343e6a | 901 | int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) |
2b144498 SD |
902 | { |
903 | struct uprobe *uprobe; | |
7b2d81d4 | 904 | int ret; |
2b144498 | 905 | |
e3343e6a | 906 | if (!inode || !uc || uc->next) |
7b2d81d4 | 907 | return -EINVAL; |
2b144498 SD |
908 | |
909 | if (offset > i_size_read(inode)) | |
7b2d81d4 | 910 | return -EINVAL; |
2b144498 SD |
911 | |
912 | ret = 0; | |
913 | mutex_lock(uprobes_hash(inode)); | |
914 | uprobe = alloc_uprobe(inode, offset); | |
7b2d81d4 | 915 | |
e3343e6a | 916 | if (uprobe && !consumer_add(uprobe, uc)) { |
7b2d81d4 | 917 | ret = __uprobe_register(uprobe); |
2b144498 SD |
918 | if (ret) { |
919 | uprobe->consumers = NULL; | |
7b2d81d4 IM |
920 | __uprobe_unregister(uprobe); |
921 | } else { | |
900771a4 | 922 | uprobe->flags |= UPROBE_RUN_HANDLER; |
7b2d81d4 | 923 | } |
2b144498 SD |
924 | } |
925 | ||
926 | mutex_unlock(uprobes_hash(inode)); | |
927 | put_uprobe(uprobe); | |
928 | ||
929 | return ret; | |
930 | } | |
931 | ||
932 | /* | |
7b2d81d4 | 933 | * uprobe_unregister - unregister a already registered probe. |
2b144498 SD |
934 | * @inode: the file in which the probe has to be removed. |
935 | * @offset: offset from the start of the file. | |
e3343e6a | 936 | * @uc: identify which probe if multiple probes are colocated. |
2b144498 | 937 | */ |
e3343e6a | 938 | void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) |
2b144498 | 939 | { |
7b2d81d4 | 940 | struct uprobe *uprobe; |
2b144498 | 941 | |
e3343e6a | 942 | if (!inode || !uc) |
2b144498 SD |
943 | return; |
944 | ||
945 | uprobe = find_uprobe(inode, offset); | |
946 | if (!uprobe) | |
947 | return; | |
948 | ||
949 | mutex_lock(uprobes_hash(inode)); | |
2b144498 | 950 | |
e3343e6a | 951 | if (consumer_del(uprobe, uc)) { |
7b2d81d4 IM |
952 | if (!uprobe->consumers) { |
953 | __uprobe_unregister(uprobe); | |
900771a4 | 954 | uprobe->flags &= ~UPROBE_RUN_HANDLER; |
7b2d81d4 | 955 | } |
2b144498 SD |
956 | } |
957 | ||
2b144498 SD |
958 | mutex_unlock(uprobes_hash(inode)); |
959 | if (uprobe) | |
960 | put_uprobe(uprobe); | |
961 | } | |
962 | ||
963 | /* | |
964 | * Of all the nodes that correspond to the given inode, return the node | |
965 | * with the least offset. | |
966 | */ | |
967 | static struct rb_node *find_least_offset_node(struct inode *inode) | |
968 | { | |
969 | struct uprobe u = { .inode = inode, .offset = 0}; | |
970 | struct rb_node *n = uprobes_tree.rb_node; | |
971 | struct rb_node *close_node = NULL; | |
972 | struct uprobe *uprobe; | |
973 | int match; | |
974 | ||
975 | while (n) { | |
976 | uprobe = rb_entry(n, struct uprobe, rb_node); | |
977 | match = match_uprobe(&u, uprobe); | |
7b2d81d4 | 978 | |
2b144498 SD |
979 | if (uprobe->inode == inode) |
980 | close_node = n; | |
981 | ||
982 | if (!match) | |
983 | return close_node; | |
984 | ||
985 | if (match < 0) | |
986 | n = n->rb_left; | |
987 | else | |
988 | n = n->rb_right; | |
989 | } | |
7b2d81d4 | 990 | |
2b144498 SD |
991 | return close_node; |
992 | } | |
993 | ||
994 | /* | |
995 | * For a given inode, build a list of probes that need to be inserted. | |
996 | */ | |
997 | static void build_probe_list(struct inode *inode, struct list_head *head) | |
998 | { | |
999 | struct uprobe *uprobe; | |
2b144498 | 1000 | unsigned long flags; |
7b2d81d4 | 1001 | struct rb_node *n; |
2b144498 SD |
1002 | |
1003 | spin_lock_irqsave(&uprobes_treelock, flags); | |
7b2d81d4 | 1004 | |
2b144498 | 1005 | n = find_least_offset_node(inode); |
7b2d81d4 | 1006 | |
2b144498 SD |
1007 | for (; n; n = rb_next(n)) { |
1008 | uprobe = rb_entry(n, struct uprobe, rb_node); | |
1009 | if (uprobe->inode != inode) | |
1010 | break; | |
1011 | ||
1012 | list_add(&uprobe->pending_list, head); | |
1013 | atomic_inc(&uprobe->ref); | |
1014 | } | |
7b2d81d4 | 1015 | |
2b144498 SD |
1016 | spin_unlock_irqrestore(&uprobes_treelock, flags); |
1017 | } | |
1018 | ||
1019 | /* | |
1020 | * Called from mmap_region. | |
1021 | * called with mm->mmap_sem acquired. | |
1022 | * | |
1023 | * Return -ve no if we fail to insert probes and we cannot | |
1024 | * bail-out. | |
7b2d81d4 IM |
1025 | * Return 0 otherwise. i.e: |
1026 | * | |
2b144498 SD |
1027 | * - successful insertion of probes |
1028 | * - (or) no possible probes to be inserted. | |
1029 | * - (or) insertion of probes failed but we can bail-out. | |
1030 | */ | |
7b2d81d4 | 1031 | int uprobe_mmap(struct vm_area_struct *vma) |
2b144498 SD |
1032 | { |
1033 | struct list_head tmp_list; | |
449d0d7c | 1034 | struct uprobe *uprobe; |
2b144498 | 1035 | struct inode *inode; |
682968e0 | 1036 | int ret, count; |
2b144498 SD |
1037 | |
1038 | if (!atomic_read(&uprobe_events) || !valid_vma(vma, true)) | |
7b2d81d4 | 1039 | return 0; |
2b144498 SD |
1040 | |
1041 | inode = vma->vm_file->f_mapping->host; | |
1042 | if (!inode) | |
7b2d81d4 | 1043 | return 0; |
2b144498 SD |
1044 | |
1045 | INIT_LIST_HEAD(&tmp_list); | |
1046 | mutex_lock(uprobes_mmap_hash(inode)); | |
1047 | build_probe_list(inode, &tmp_list); | |
7b2d81d4 IM |
1048 | |
1049 | ret = 0; | |
682968e0 | 1050 | count = 0; |
7b2d81d4 | 1051 | |
449d0d7c | 1052 | list_for_each_entry(uprobe, &tmp_list, pending_list) { |
2b144498 | 1053 | if (!ret) { |
816c03fb | 1054 | loff_t vaddr = vma_address(vma, uprobe->offset); |
682968e0 SD |
1055 | |
1056 | if (vaddr < vma->vm_start || vaddr >= vma->vm_end) { | |
1057 | put_uprobe(uprobe); | |
1058 | continue; | |
2b144498 | 1059 | } |
682968e0 SD |
1060 | |
1061 | ret = install_breakpoint(uprobe, vma->vm_mm, vma, vaddr); | |
c5784de2 PZ |
1062 | /* |
1063 | * We can race against uprobe_register(), see the | |
1064 | * comment near uprobe_hash(). | |
1065 | */ | |
682968e0 SD |
1066 | if (ret == -EEXIST) { |
1067 | ret = 0; | |
1068 | ||
1069 | if (!is_swbp_at_addr(vma->vm_mm, vaddr)) | |
1070 | continue; | |
1071 | ||
1072 | /* | |
1073 | * Unable to insert a breakpoint, but | |
1074 | * breakpoint lies underneath. Increment the | |
1075 | * probe count. | |
1076 | */ | |
1077 | atomic_inc(&vma->vm_mm->uprobes_state.count); | |
1078 | } | |
1079 | ||
1080 | if (!ret) | |
1081 | count++; | |
2b144498 SD |
1082 | } |
1083 | put_uprobe(uprobe); | |
1084 | } | |
1085 | ||
1086 | mutex_unlock(uprobes_mmap_hash(inode)); | |
1087 | ||
682968e0 SD |
1088 | if (ret) |
1089 | atomic_sub(count, &vma->vm_mm->uprobes_state.count); | |
1090 | ||
2b144498 SD |
1091 | return ret; |
1092 | } | |
1093 | ||
682968e0 SD |
1094 | /* |
1095 | * Called in context of a munmap of a vma. | |
1096 | */ | |
cbc91f71 | 1097 | void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end) |
682968e0 SD |
1098 | { |
1099 | struct list_head tmp_list; | |
449d0d7c | 1100 | struct uprobe *uprobe; |
682968e0 SD |
1101 | struct inode *inode; |
1102 | ||
1103 | if (!atomic_read(&uprobe_events) || !valid_vma(vma, false)) | |
1104 | return; | |
1105 | ||
1106 | if (!atomic_read(&vma->vm_mm->uprobes_state.count)) | |
1107 | return; | |
1108 | ||
1109 | inode = vma->vm_file->f_mapping->host; | |
1110 | if (!inode) | |
1111 | return; | |
1112 | ||
1113 | INIT_LIST_HEAD(&tmp_list); | |
1114 | mutex_lock(uprobes_mmap_hash(inode)); | |
1115 | build_probe_list(inode, &tmp_list); | |
1116 | ||
449d0d7c | 1117 | list_for_each_entry(uprobe, &tmp_list, pending_list) { |
816c03fb | 1118 | loff_t vaddr = vma_address(vma, uprobe->offset); |
682968e0 | 1119 | |
cbc91f71 | 1120 | if (vaddr >= start && vaddr < end) { |
682968e0 SD |
1121 | /* |
1122 | * An unregister could have removed the probe before | |
1123 | * unmap. So check before we decrement the count. | |
1124 | */ | |
1125 | if (is_swbp_at_addr(vma->vm_mm, vaddr) == 1) | |
1126 | atomic_dec(&vma->vm_mm->uprobes_state.count); | |
1127 | } | |
1128 | put_uprobe(uprobe); | |
1129 | } | |
1130 | mutex_unlock(uprobes_mmap_hash(inode)); | |
1131 | } | |
1132 | ||
d4b3b638 SD |
1133 | /* Slot allocation for XOL */ |
1134 | static int xol_add_vma(struct xol_area *area) | |
1135 | { | |
1136 | struct mm_struct *mm; | |
1137 | int ret; | |
1138 | ||
1139 | area->page = alloc_page(GFP_HIGHUSER); | |
1140 | if (!area->page) | |
1141 | return -ENOMEM; | |
1142 | ||
1143 | ret = -EALREADY; | |
1144 | mm = current->mm; | |
1145 | ||
1146 | down_write(&mm->mmap_sem); | |
1147 | if (mm->uprobes_state.xol_area) | |
1148 | goto fail; | |
1149 | ||
1150 | ret = -ENOMEM; | |
1151 | ||
1152 | /* Try to map as high as possible, this is only a hint. */ | |
1153 | area->vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, PAGE_SIZE, 0, 0); | |
1154 | if (area->vaddr & ~PAGE_MASK) { | |
1155 | ret = area->vaddr; | |
1156 | goto fail; | |
1157 | } | |
1158 | ||
1159 | ret = install_special_mapping(mm, area->vaddr, PAGE_SIZE, | |
1160 | VM_EXEC|VM_MAYEXEC|VM_DONTCOPY|VM_IO, &area->page); | |
1161 | if (ret) | |
1162 | goto fail; | |
1163 | ||
1164 | smp_wmb(); /* pairs with get_xol_area() */ | |
1165 | mm->uprobes_state.xol_area = area; | |
1166 | ret = 0; | |
1167 | ||
1168 | fail: | |
1169 | up_write(&mm->mmap_sem); | |
1170 | if (ret) | |
1171 | __free_page(area->page); | |
1172 | ||
1173 | return ret; | |
1174 | } | |
1175 | ||
1176 | static struct xol_area *get_xol_area(struct mm_struct *mm) | |
1177 | { | |
1178 | struct xol_area *area; | |
1179 | ||
1180 | area = mm->uprobes_state.xol_area; | |
1181 | smp_read_barrier_depends(); /* pairs with wmb in xol_add_vma() */ | |
1182 | ||
1183 | return area; | |
1184 | } | |
1185 | ||
1186 | /* | |
1187 | * xol_alloc_area - Allocate process's xol_area. | |
1188 | * This area will be used for storing instructions for execution out of | |
1189 | * line. | |
1190 | * | |
1191 | * Returns the allocated area or NULL. | |
1192 | */ | |
1193 | static struct xol_area *xol_alloc_area(void) | |
1194 | { | |
1195 | struct xol_area *area; | |
1196 | ||
1197 | area = kzalloc(sizeof(*area), GFP_KERNEL); | |
1198 | if (unlikely(!area)) | |
1199 | return NULL; | |
1200 | ||
1201 | area->bitmap = kzalloc(BITS_TO_LONGS(UINSNS_PER_PAGE) * sizeof(long), GFP_KERNEL); | |
1202 | ||
1203 | if (!area->bitmap) | |
1204 | goto fail; | |
1205 | ||
1206 | init_waitqueue_head(&area->wq); | |
1207 | if (!xol_add_vma(area)) | |
1208 | return area; | |
1209 | ||
1210 | fail: | |
1211 | kfree(area->bitmap); | |
1212 | kfree(area); | |
1213 | ||
1214 | return get_xol_area(current->mm); | |
1215 | } | |
1216 | ||
1217 | /* | |
1218 | * uprobe_clear_state - Free the area allocated for slots. | |
1219 | */ | |
1220 | void uprobe_clear_state(struct mm_struct *mm) | |
1221 | { | |
1222 | struct xol_area *area = mm->uprobes_state.xol_area; | |
1223 | ||
1224 | if (!area) | |
1225 | return; | |
1226 | ||
1227 | put_page(area->page); | |
1228 | kfree(area->bitmap); | |
1229 | kfree(area); | |
1230 | } | |
1231 | ||
1232 | /* | |
1233 | * uprobe_reset_state - Free the area allocated for slots. | |
1234 | */ | |
1235 | void uprobe_reset_state(struct mm_struct *mm) | |
1236 | { | |
1237 | mm->uprobes_state.xol_area = NULL; | |
682968e0 | 1238 | atomic_set(&mm->uprobes_state.count, 0); |
d4b3b638 SD |
1239 | } |
1240 | ||
1241 | /* | |
1242 | * - search for a free slot. | |
1243 | */ | |
1244 | static unsigned long xol_take_insn_slot(struct xol_area *area) | |
1245 | { | |
1246 | unsigned long slot_addr; | |
1247 | int slot_nr; | |
1248 | ||
1249 | do { | |
1250 | slot_nr = find_first_zero_bit(area->bitmap, UINSNS_PER_PAGE); | |
1251 | if (slot_nr < UINSNS_PER_PAGE) { | |
1252 | if (!test_and_set_bit(slot_nr, area->bitmap)) | |
1253 | break; | |
1254 | ||
1255 | slot_nr = UINSNS_PER_PAGE; | |
1256 | continue; | |
1257 | } | |
1258 | wait_event(area->wq, (atomic_read(&area->slot_count) < UINSNS_PER_PAGE)); | |
1259 | } while (slot_nr >= UINSNS_PER_PAGE); | |
1260 | ||
1261 | slot_addr = area->vaddr + (slot_nr * UPROBE_XOL_SLOT_BYTES); | |
1262 | atomic_inc(&area->slot_count); | |
1263 | ||
1264 | return slot_addr; | |
1265 | } | |
1266 | ||
1267 | /* | |
1268 | * xol_get_insn_slot - If was not allocated a slot, then | |
1269 | * allocate a slot. | |
1270 | * Returns the allocated slot address or 0. | |
1271 | */ | |
1272 | static unsigned long xol_get_insn_slot(struct uprobe *uprobe, unsigned long slot_addr) | |
1273 | { | |
1274 | struct xol_area *area; | |
1275 | unsigned long offset; | |
1276 | void *vaddr; | |
1277 | ||
1278 | area = get_xol_area(current->mm); | |
1279 | if (!area) { | |
1280 | area = xol_alloc_area(); | |
1281 | if (!area) | |
1282 | return 0; | |
1283 | } | |
1284 | current->utask->xol_vaddr = xol_take_insn_slot(area); | |
1285 | ||
1286 | /* | |
1287 | * Initialize the slot if xol_vaddr points to valid | |
1288 | * instruction slot. | |
1289 | */ | |
1290 | if (unlikely(!current->utask->xol_vaddr)) | |
1291 | return 0; | |
1292 | ||
1293 | current->utask->vaddr = slot_addr; | |
1294 | offset = current->utask->xol_vaddr & ~PAGE_MASK; | |
1295 | vaddr = kmap_atomic(area->page); | |
1296 | memcpy(vaddr + offset, uprobe->arch.insn, MAX_UINSN_BYTES); | |
1297 | kunmap_atomic(vaddr); | |
1298 | ||
1299 | return current->utask->xol_vaddr; | |
1300 | } | |
1301 | ||
1302 | /* | |
1303 | * xol_free_insn_slot - If slot was earlier allocated by | |
1304 | * @xol_get_insn_slot(), make the slot available for | |
1305 | * subsequent requests. | |
1306 | */ | |
1307 | static void xol_free_insn_slot(struct task_struct *tsk) | |
1308 | { | |
1309 | struct xol_area *area; | |
1310 | unsigned long vma_end; | |
1311 | unsigned long slot_addr; | |
1312 | ||
1313 | if (!tsk->mm || !tsk->mm->uprobes_state.xol_area || !tsk->utask) | |
1314 | return; | |
1315 | ||
1316 | slot_addr = tsk->utask->xol_vaddr; | |
1317 | ||
1318 | if (unlikely(!slot_addr || IS_ERR_VALUE(slot_addr))) | |
1319 | return; | |
1320 | ||
1321 | area = tsk->mm->uprobes_state.xol_area; | |
1322 | vma_end = area->vaddr + PAGE_SIZE; | |
1323 | if (area->vaddr <= slot_addr && slot_addr < vma_end) { | |
1324 | unsigned long offset; | |
1325 | int slot_nr; | |
1326 | ||
1327 | offset = slot_addr - area->vaddr; | |
1328 | slot_nr = offset / UPROBE_XOL_SLOT_BYTES; | |
1329 | if (slot_nr >= UINSNS_PER_PAGE) | |
1330 | return; | |
1331 | ||
1332 | clear_bit(slot_nr, area->bitmap); | |
1333 | atomic_dec(&area->slot_count); | |
1334 | if (waitqueue_active(&area->wq)) | |
1335 | wake_up(&area->wq); | |
1336 | ||
1337 | tsk->utask->xol_vaddr = 0; | |
1338 | } | |
1339 | } | |
1340 | ||
0326f5a9 SD |
1341 | /** |
1342 | * uprobe_get_swbp_addr - compute address of swbp given post-swbp regs | |
1343 | * @regs: Reflects the saved state of the task after it has hit a breakpoint | |
1344 | * instruction. | |
1345 | * Return the address of the breakpoint instruction. | |
1346 | */ | |
1347 | unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs) | |
1348 | { | |
1349 | return instruction_pointer(regs) - UPROBE_SWBP_INSN_SIZE; | |
1350 | } | |
1351 | ||
1352 | /* | |
1353 | * Called with no locks held. | |
1354 | * Called in context of a exiting or a exec-ing thread. | |
1355 | */ | |
1356 | void uprobe_free_utask(struct task_struct *t) | |
1357 | { | |
1358 | struct uprobe_task *utask = t->utask; | |
1359 | ||
0326f5a9 SD |
1360 | if (!utask) |
1361 | return; | |
1362 | ||
1363 | if (utask->active_uprobe) | |
1364 | put_uprobe(utask->active_uprobe); | |
1365 | ||
d4b3b638 | 1366 | xol_free_insn_slot(t); |
0326f5a9 SD |
1367 | kfree(utask); |
1368 | t->utask = NULL; | |
1369 | } | |
1370 | ||
1371 | /* | |
1372 | * Called in context of a new clone/fork from copy_process. | |
1373 | */ | |
1374 | void uprobe_copy_process(struct task_struct *t) | |
1375 | { | |
1376 | t->utask = NULL; | |
0326f5a9 SD |
1377 | } |
1378 | ||
1379 | /* | |
1380 | * Allocate a uprobe_task object for the task. | |
1381 | * Called when the thread hits a breakpoint for the first time. | |
1382 | * | |
1383 | * Returns: | |
1384 | * - pointer to new uprobe_task on success | |
1385 | * - NULL otherwise | |
1386 | */ | |
1387 | static struct uprobe_task *add_utask(void) | |
1388 | { | |
1389 | struct uprobe_task *utask; | |
1390 | ||
1391 | utask = kzalloc(sizeof *utask, GFP_KERNEL); | |
1392 | if (unlikely(!utask)) | |
1393 | return NULL; | |
1394 | ||
1395 | utask->active_uprobe = NULL; | |
1396 | current->utask = utask; | |
1397 | return utask; | |
1398 | } | |
1399 | ||
1400 | /* Prepare to single-step probed instruction out of line. */ | |
1401 | static int | |
1402 | pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long vaddr) | |
1403 | { | |
d4b3b638 SD |
1404 | if (xol_get_insn_slot(uprobe, vaddr) && !arch_uprobe_pre_xol(&uprobe->arch, regs)) |
1405 | return 0; | |
1406 | ||
0326f5a9 SD |
1407 | return -EFAULT; |
1408 | } | |
1409 | ||
1410 | /* | |
1411 | * If we are singlestepping, then ensure this thread is not connected to | |
1412 | * non-fatal signals until completion of singlestep. When xol insn itself | |
1413 | * triggers the signal, restart the original insn even if the task is | |
1414 | * already SIGKILL'ed (since coredump should report the correct ip). This | |
1415 | * is even more important if the task has a handler for SIGSEGV/etc, The | |
1416 | * _same_ instruction should be repeated again after return from the signal | |
1417 | * handler, and SSTEP can never finish in this case. | |
1418 | */ | |
1419 | bool uprobe_deny_signal(void) | |
1420 | { | |
1421 | struct task_struct *t = current; | |
1422 | struct uprobe_task *utask = t->utask; | |
1423 | ||
1424 | if (likely(!utask || !utask->active_uprobe)) | |
1425 | return false; | |
1426 | ||
1427 | WARN_ON_ONCE(utask->state != UTASK_SSTEP); | |
1428 | ||
1429 | if (signal_pending(t)) { | |
1430 | spin_lock_irq(&t->sighand->siglock); | |
1431 | clear_tsk_thread_flag(t, TIF_SIGPENDING); | |
1432 | spin_unlock_irq(&t->sighand->siglock); | |
1433 | ||
1434 | if (__fatal_signal_pending(t) || arch_uprobe_xol_was_trapped(t)) { | |
1435 | utask->state = UTASK_SSTEP_TRAPPED; | |
1436 | set_tsk_thread_flag(t, TIF_UPROBE); | |
1437 | set_tsk_thread_flag(t, TIF_NOTIFY_RESUME); | |
1438 | } | |
1439 | } | |
1440 | ||
1441 | return true; | |
1442 | } | |
1443 | ||
1444 | /* | |
1445 | * Avoid singlestepping the original instruction if the original instruction | |
1446 | * is a NOP or can be emulated. | |
1447 | */ | |
1448 | static bool can_skip_sstep(struct uprobe *uprobe, struct pt_regs *regs) | |
1449 | { | |
1450 | if (arch_uprobe_skip_sstep(&uprobe->arch, regs)) | |
1451 | return true; | |
1452 | ||
1453 | uprobe->flags &= ~UPROBE_SKIP_SSTEP; | |
1454 | return false; | |
1455 | } | |
1456 | ||
d790d346 | 1457 | static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp) |
0326f5a9 | 1458 | { |
3a9ea052 ON |
1459 | struct mm_struct *mm = current->mm; |
1460 | struct uprobe *uprobe = NULL; | |
0326f5a9 | 1461 | struct vm_area_struct *vma; |
0326f5a9 | 1462 | |
0326f5a9 SD |
1463 | down_read(&mm->mmap_sem); |
1464 | vma = find_vma(mm, bp_vaddr); | |
3a9ea052 ON |
1465 | if (vma && vma->vm_start <= bp_vaddr) { |
1466 | if (valid_vma(vma, false)) { | |
1467 | struct inode *inode; | |
1468 | loff_t offset; | |
0326f5a9 | 1469 | |
3a9ea052 ON |
1470 | inode = vma->vm_file->f_mapping->host; |
1471 | offset = bp_vaddr - vma->vm_start; | |
1472 | offset += (vma->vm_pgoff << PAGE_SHIFT); | |
1473 | uprobe = find_uprobe(inode, offset); | |
1474 | } | |
d790d346 ON |
1475 | |
1476 | if (!uprobe) | |
1477 | *is_swbp = is_swbp_at_addr(mm, bp_vaddr); | |
1478 | } else { | |
1479 | *is_swbp = -EFAULT; | |
0326f5a9 | 1480 | } |
0326f5a9 SD |
1481 | up_read(&mm->mmap_sem); |
1482 | ||
3a9ea052 ON |
1483 | return uprobe; |
1484 | } | |
1485 | ||
1486 | /* | |
1487 | * Run handler and ask thread to singlestep. | |
1488 | * Ensure all non-fatal signals cannot interrupt thread while it singlesteps. | |
1489 | */ | |
1490 | static void handle_swbp(struct pt_regs *regs) | |
1491 | { | |
1492 | struct uprobe_task *utask; | |
1493 | struct uprobe *uprobe; | |
1494 | unsigned long bp_vaddr; | |
56bb4cf6 | 1495 | int uninitialized_var(is_swbp); |
3a9ea052 ON |
1496 | |
1497 | bp_vaddr = uprobe_get_swbp_addr(regs); | |
d790d346 | 1498 | uprobe = find_active_uprobe(bp_vaddr, &is_swbp); |
3a9ea052 | 1499 | |
0326f5a9 | 1500 | if (!uprobe) { |
56bb4cf6 ON |
1501 | if (is_swbp > 0) { |
1502 | /* No matching uprobe; signal SIGTRAP. */ | |
1503 | send_sig(SIGTRAP, current, 0); | |
1504 | } else { | |
1505 | /* | |
1506 | * Either we raced with uprobe_unregister() or we can't | |
1507 | * access this memory. The latter is only possible if | |
1508 | * another thread plays with our ->mm. In both cases | |
1509 | * we can simply restart. If this vma was unmapped we | |
1510 | * can pretend this insn was not executed yet and get | |
1511 | * the (correct) SIGSEGV after restart. | |
1512 | */ | |
1513 | instruction_pointer_set(regs, bp_vaddr); | |
1514 | } | |
0326f5a9 SD |
1515 | return; |
1516 | } | |
1517 | ||
1518 | utask = current->utask; | |
1519 | if (!utask) { | |
1520 | utask = add_utask(); | |
1521 | /* Cannot allocate; re-execute the instruction. */ | |
1522 | if (!utask) | |
1523 | goto cleanup_ret; | |
1524 | } | |
1525 | utask->active_uprobe = uprobe; | |
1526 | handler_chain(uprobe, regs); | |
1527 | if (uprobe->flags & UPROBE_SKIP_SSTEP && can_skip_sstep(uprobe, regs)) | |
1528 | goto cleanup_ret; | |
1529 | ||
1530 | utask->state = UTASK_SSTEP; | |
1531 | if (!pre_ssout(uprobe, regs, bp_vaddr)) { | |
1532 | user_enable_single_step(current); | |
1533 | return; | |
1534 | } | |
1535 | ||
1536 | cleanup_ret: | |
1537 | if (utask) { | |
1538 | utask->active_uprobe = NULL; | |
1539 | utask->state = UTASK_RUNNING; | |
1540 | } | |
1541 | if (uprobe) { | |
1542 | if (!(uprobe->flags & UPROBE_SKIP_SSTEP)) | |
1543 | ||
1544 | /* | |
1545 | * cannot singlestep; cannot skip instruction; | |
1546 | * re-execute the instruction. | |
1547 | */ | |
1548 | instruction_pointer_set(regs, bp_vaddr); | |
1549 | ||
1550 | put_uprobe(uprobe); | |
1551 | } | |
1552 | } | |
1553 | ||
1554 | /* | |
1555 | * Perform required fix-ups and disable singlestep. | |
1556 | * Allow pending signals to take effect. | |
1557 | */ | |
1558 | static void handle_singlestep(struct uprobe_task *utask, struct pt_regs *regs) | |
1559 | { | |
1560 | struct uprobe *uprobe; | |
1561 | ||
1562 | uprobe = utask->active_uprobe; | |
1563 | if (utask->state == UTASK_SSTEP_ACK) | |
1564 | arch_uprobe_post_xol(&uprobe->arch, regs); | |
1565 | else if (utask->state == UTASK_SSTEP_TRAPPED) | |
1566 | arch_uprobe_abort_xol(&uprobe->arch, regs); | |
1567 | else | |
1568 | WARN_ON_ONCE(1); | |
1569 | ||
1570 | put_uprobe(uprobe); | |
1571 | utask->active_uprobe = NULL; | |
1572 | utask->state = UTASK_RUNNING; | |
1573 | user_disable_single_step(current); | |
d4b3b638 | 1574 | xol_free_insn_slot(current); |
0326f5a9 SD |
1575 | |
1576 | spin_lock_irq(¤t->sighand->siglock); | |
1577 | recalc_sigpending(); /* see uprobe_deny_signal() */ | |
1578 | spin_unlock_irq(¤t->sighand->siglock); | |
1579 | } | |
1580 | ||
1581 | /* | |
1582 | * On breakpoint hit, breakpoint notifier sets the TIF_UPROBE flag. (and on | |
1583 | * subsequent probe hits on the thread sets the state to UTASK_BP_HIT) and | |
1584 | * allows the thread to return from interrupt. | |
1585 | * | |
1586 | * On singlestep exception, singlestep notifier sets the TIF_UPROBE flag and | |
1587 | * also sets the state to UTASK_SSTEP_ACK and allows the thread to return from | |
1588 | * interrupt. | |
1589 | * | |
1590 | * While returning to userspace, thread notices the TIF_UPROBE flag and calls | |
1591 | * uprobe_notify_resume(). | |
1592 | */ | |
1593 | void uprobe_notify_resume(struct pt_regs *regs) | |
1594 | { | |
1595 | struct uprobe_task *utask; | |
1596 | ||
1597 | utask = current->utask; | |
1598 | if (!utask || utask->state == UTASK_BP_HIT) | |
1599 | handle_swbp(regs); | |
1600 | else | |
1601 | handle_singlestep(utask, regs); | |
1602 | } | |
1603 | ||
1604 | /* | |
1605 | * uprobe_pre_sstep_notifier gets called from interrupt context as part of | |
1606 | * notifier mechanism. Set TIF_UPROBE flag and indicate breakpoint hit. | |
1607 | */ | |
1608 | int uprobe_pre_sstep_notifier(struct pt_regs *regs) | |
1609 | { | |
1610 | struct uprobe_task *utask; | |
1611 | ||
682968e0 SD |
1612 | if (!current->mm || !atomic_read(¤t->mm->uprobes_state.count)) |
1613 | /* task is currently not uprobed */ | |
0326f5a9 SD |
1614 | return 0; |
1615 | ||
1616 | utask = current->utask; | |
1617 | if (utask) | |
1618 | utask->state = UTASK_BP_HIT; | |
1619 | ||
1620 | set_thread_flag(TIF_UPROBE); | |
0326f5a9 SD |
1621 | |
1622 | return 1; | |
1623 | } | |
1624 | ||
1625 | /* | |
1626 | * uprobe_post_sstep_notifier gets called in interrupt context as part of notifier | |
1627 | * mechanism. Set TIF_UPROBE flag and indicate completion of singlestep. | |
1628 | */ | |
1629 | int uprobe_post_sstep_notifier(struct pt_regs *regs) | |
1630 | { | |
1631 | struct uprobe_task *utask = current->utask; | |
1632 | ||
1633 | if (!current->mm || !utask || !utask->active_uprobe) | |
1634 | /* task is currently not uprobed */ | |
1635 | return 0; | |
1636 | ||
1637 | utask->state = UTASK_SSTEP_ACK; | |
1638 | set_thread_flag(TIF_UPROBE); | |
1639 | return 1; | |
1640 | } | |
1641 | ||
1642 | static struct notifier_block uprobe_exception_nb = { | |
1643 | .notifier_call = arch_uprobe_exception_notify, | |
1644 | .priority = INT_MAX-1, /* notified after kprobes, kgdb */ | |
1645 | }; | |
1646 | ||
2b144498 SD |
1647 | static int __init init_uprobes(void) |
1648 | { | |
1649 | int i; | |
1650 | ||
1651 | for (i = 0; i < UPROBES_HASH_SZ; i++) { | |
1652 | mutex_init(&uprobes_mutex[i]); | |
1653 | mutex_init(&uprobes_mmap_mutex[i]); | |
1654 | } | |
0326f5a9 SD |
1655 | |
1656 | return register_die_notifier(&uprobe_exception_nb); | |
2b144498 | 1657 | } |
0326f5a9 | 1658 | module_init(init_uprobes); |
2b144498 SD |
1659 | |
1660 | static void __exit exit_uprobes(void) | |
1661 | { | |
1662 | } | |
2b144498 | 1663 | module_exit(exit_uprobes); |