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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 */ | |
194f8dcb | 35 | #include "../../mm/internal.h" /* munlock_vma_page */ |
7b2d81d4 | 36 | |
2b144498 SD |
37 | #include <linux/uprobes.h> |
38 | ||
d4b3b638 SD |
39 | #define UINSNS_PER_PAGE (PAGE_SIZE/UPROBE_XOL_SLOT_BYTES) |
40 | #define MAX_UPROBE_XOL_SLOTS UINSNS_PER_PAGE | |
41 | ||
2b144498 | 42 | static struct rb_root uprobes_tree = RB_ROOT; |
7b2d81d4 | 43 | |
2b144498 SD |
44 | static DEFINE_SPINLOCK(uprobes_treelock); /* serialize rbtree access */ |
45 | ||
46 | #define UPROBES_HASH_SZ 13 | |
7b2d81d4 | 47 | |
c5784de2 PZ |
48 | /* |
49 | * We need separate register/unregister and mmap/munmap lock hashes because | |
50 | * of mmap_sem nesting. | |
51 | * | |
52 | * uprobe_register() needs to install probes on (potentially) all processes | |
53 | * and thus needs to acquire multiple mmap_sems (consequtively, not | |
54 | * concurrently), whereas uprobe_mmap() is called while holding mmap_sem | |
55 | * for the particular process doing the mmap. | |
56 | * | |
57 | * uprobe_register()->register_for_each_vma() needs to drop/acquire mmap_sem | |
58 | * because of lock order against i_mmap_mutex. This means there's a hole in | |
59 | * the register vma iteration where a mmap() can happen. | |
60 | * | |
61 | * Thus uprobe_register() can race with uprobe_mmap() and we can try and | |
62 | * install a probe where one is already installed. | |
63 | */ | |
64 | ||
2b144498 SD |
65 | /* serialize (un)register */ |
66 | static struct mutex uprobes_mutex[UPROBES_HASH_SZ]; | |
7b2d81d4 IM |
67 | |
68 | #define uprobes_hash(v) (&uprobes_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ]) | |
2b144498 SD |
69 | |
70 | /* serialize uprobe->pending_list */ | |
71 | static struct mutex uprobes_mmap_mutex[UPROBES_HASH_SZ]; | |
7b2d81d4 | 72 | #define uprobes_mmap_hash(v) (&uprobes_mmap_mutex[((unsigned long)(v)) % UPROBES_HASH_SZ]) |
2b144498 SD |
73 | |
74 | /* | |
7b2d81d4 | 75 | * uprobe_events allows us to skip the uprobe_mmap if there are no uprobe |
2b144498 SD |
76 | * events active at this time. Probably a fine grained per inode count is |
77 | * better? | |
78 | */ | |
79 | static atomic_t uprobe_events = ATOMIC_INIT(0); | |
80 | ||
cb9a19fe | 81 | /* Have a copy of original instruction */ |
71434f2f | 82 | #define UPROBE_COPY_INSN 0 |
cb9a19fe | 83 | /* Dont run handlers when first register/ last unregister in progress*/ |
71434f2f | 84 | #define UPROBE_RUN_HANDLER 1 |
cb9a19fe | 85 | /* Can skip singlestep */ |
71434f2f | 86 | #define UPROBE_SKIP_SSTEP 2 |
cb9a19fe | 87 | |
3ff54efd SD |
88 | struct uprobe { |
89 | struct rb_node rb_node; /* node in the rb tree */ | |
90 | atomic_t ref; | |
91 | struct rw_semaphore consumer_rwsem; | |
4710f05f | 92 | struct mutex copy_mutex; /* TODO: kill me and UPROBE_COPY_INSN */ |
3ff54efd SD |
93 | struct list_head pending_list; |
94 | struct uprobe_consumer *consumers; | |
95 | struct inode *inode; /* Also hold a ref to inode */ | |
96 | loff_t offset; | |
71434f2f | 97 | unsigned long flags; |
3ff54efd SD |
98 | struct arch_uprobe arch; |
99 | }; | |
100 | ||
2b144498 SD |
101 | /* |
102 | * valid_vma: Verify if the specified vma is an executable vma | |
103 | * Relax restrictions while unregistering: vm_flags might have | |
104 | * changed after breakpoint was inserted. | |
105 | * - is_register: indicates if we are in register context. | |
106 | * - Return 1 if the specified virtual address is in an | |
107 | * executable vma. | |
108 | */ | |
109 | static bool valid_vma(struct vm_area_struct *vma, bool is_register) | |
110 | { | |
e40cfce6 | 111 | vm_flags_t flags = VM_HUGETLB | VM_MAYEXEC | VM_SHARED; |
2b144498 | 112 | |
e40cfce6 ON |
113 | if (is_register) |
114 | flags |= VM_WRITE; | |
2b144498 | 115 | |
e40cfce6 | 116 | return vma->vm_file && (vma->vm_flags & flags) == VM_MAYEXEC; |
2b144498 SD |
117 | } |
118 | ||
57683f72 | 119 | static unsigned long offset_to_vaddr(struct vm_area_struct *vma, loff_t offset) |
2b144498 | 120 | { |
57683f72 | 121 | return vma->vm_start + offset - ((loff_t)vma->vm_pgoff << PAGE_SHIFT); |
2b144498 SD |
122 | } |
123 | ||
cb113b47 ON |
124 | static loff_t vaddr_to_offset(struct vm_area_struct *vma, unsigned long vaddr) |
125 | { | |
126 | return ((loff_t)vma->vm_pgoff << PAGE_SHIFT) + (vaddr - vma->vm_start); | |
127 | } | |
128 | ||
2b144498 SD |
129 | /** |
130 | * __replace_page - replace page in vma by new page. | |
131 | * based on replace_page in mm/ksm.c | |
132 | * | |
133 | * @vma: vma that holds the pte pointing to page | |
c517ee74 | 134 | * @addr: address the old @page is mapped at |
2b144498 SD |
135 | * @page: the cowed page we are replacing by kpage |
136 | * @kpage: the modified page we replace page by | |
137 | * | |
138 | * Returns 0 on success, -EFAULT on failure. | |
139 | */ | |
c517ee74 ON |
140 | static int __replace_page(struct vm_area_struct *vma, unsigned long addr, |
141 | struct page *page, struct page *kpage) | |
2b144498 SD |
142 | { |
143 | struct mm_struct *mm = vma->vm_mm; | |
5323ce71 ON |
144 | spinlock_t *ptl; |
145 | pte_t *ptep; | |
9f92448c | 146 | int err; |
6bdb913f HE |
147 | /* For mmu_notifiers */ |
148 | const unsigned long mmun_start = addr; | |
149 | const unsigned long mmun_end = addr + PAGE_SIZE; | |
2b144498 | 150 | |
194f8dcb | 151 | /* For try_to_free_swap() and munlock_vma_page() below */ |
9f92448c ON |
152 | lock_page(page); |
153 | ||
6bdb913f | 154 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
9f92448c | 155 | err = -EAGAIN; |
5323ce71 | 156 | ptep = page_check_address(page, mm, addr, &ptl, 0); |
2b144498 | 157 | if (!ptep) |
9f92448c | 158 | goto unlock; |
2b144498 SD |
159 | |
160 | get_page(kpage); | |
161 | page_add_new_anon_rmap(kpage, vma, addr); | |
162 | ||
7396fa81 SD |
163 | if (!PageAnon(page)) { |
164 | dec_mm_counter(mm, MM_FILEPAGES); | |
165 | inc_mm_counter(mm, MM_ANONPAGES); | |
166 | } | |
167 | ||
2b144498 SD |
168 | flush_cache_page(vma, addr, pte_pfn(*ptep)); |
169 | ptep_clear_flush(vma, addr, ptep); | |
170 | set_pte_at_notify(mm, addr, ptep, mk_pte(kpage, vma->vm_page_prot)); | |
171 | ||
172 | page_remove_rmap(page); | |
173 | if (!page_mapped(page)) | |
174 | try_to_free_swap(page); | |
2b144498 | 175 | pte_unmap_unlock(ptep, ptl); |
2b144498 | 176 | |
194f8dcb ON |
177 | if (vma->vm_flags & VM_LOCKED) |
178 | munlock_vma_page(page); | |
179 | put_page(page); | |
180 | ||
9f92448c ON |
181 | err = 0; |
182 | unlock: | |
6bdb913f | 183 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
9f92448c ON |
184 | unlock_page(page); |
185 | return err; | |
2b144498 SD |
186 | } |
187 | ||
188 | /** | |
5cb4ac3a | 189 | * is_swbp_insn - check if instruction is breakpoint instruction. |
2b144498 | 190 | * @insn: instruction to be checked. |
5cb4ac3a | 191 | * Default implementation of is_swbp_insn |
2b144498 SD |
192 | * Returns true if @insn is a breakpoint instruction. |
193 | */ | |
5cb4ac3a | 194 | bool __weak is_swbp_insn(uprobe_opcode_t *insn) |
2b144498 | 195 | { |
5cb4ac3a | 196 | return *insn == UPROBE_SWBP_INSN; |
2b144498 SD |
197 | } |
198 | ||
cceb55aa ON |
199 | static void copy_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *opcode) |
200 | { | |
201 | void *kaddr = kmap_atomic(page); | |
202 | memcpy(opcode, kaddr + (vaddr & ~PAGE_MASK), UPROBE_SWBP_INSN_SIZE); | |
203 | kunmap_atomic(kaddr); | |
204 | } | |
205 | ||
ed6f6a50 ON |
206 | static int verify_opcode(struct page *page, unsigned long vaddr, uprobe_opcode_t *new_opcode) |
207 | { | |
208 | uprobe_opcode_t old_opcode; | |
209 | bool is_swbp; | |
210 | ||
211 | copy_opcode(page, vaddr, &old_opcode); | |
212 | is_swbp = is_swbp_insn(&old_opcode); | |
213 | ||
214 | if (is_swbp_insn(new_opcode)) { | |
215 | if (is_swbp) /* register: already installed? */ | |
216 | return 0; | |
217 | } else { | |
218 | if (!is_swbp) /* unregister: was it changed by us? */ | |
076a365b | 219 | return 0; |
ed6f6a50 ON |
220 | } |
221 | ||
222 | return 1; | |
223 | } | |
224 | ||
2b144498 SD |
225 | /* |
226 | * NOTE: | |
227 | * Expect the breakpoint instruction to be the smallest size instruction for | |
228 | * the architecture. If an arch has variable length instruction and the | |
229 | * breakpoint instruction is not of the smallest length instruction | |
cceb55aa | 230 | * supported by that architecture then we need to modify is_swbp_at_addr and |
2b144498 SD |
231 | * write_opcode accordingly. This would never be a problem for archs that |
232 | * have fixed length instructions. | |
233 | */ | |
234 | ||
235 | /* | |
236 | * write_opcode - write the opcode at a given virtual address. | |
237 | * @mm: the probed process address space. | |
2b144498 SD |
238 | * @vaddr: the virtual address to store the opcode. |
239 | * @opcode: opcode to be written at @vaddr. | |
240 | * | |
241 | * Called with mm->mmap_sem held (for read and with a reference to | |
242 | * mm). | |
243 | * | |
244 | * For mm @mm, write the opcode at @vaddr. | |
245 | * Return 0 (success) or a negative errno. | |
246 | */ | |
cceb55aa ON |
247 | static int write_opcode(struct mm_struct *mm, unsigned long vaddr, |
248 | uprobe_opcode_t opcode) | |
2b144498 SD |
249 | { |
250 | struct page *old_page, *new_page; | |
2b144498 SD |
251 | void *vaddr_old, *vaddr_new; |
252 | struct vm_area_struct *vma; | |
2b144498 | 253 | int ret; |
f403072c | 254 | |
5323ce71 | 255 | retry: |
2b144498 | 256 | /* Read the page with vaddr into memory */ |
75ed82ea | 257 | ret = get_user_pages(NULL, mm, vaddr, 1, 0, 1, &old_page, &vma); |
2b144498 SD |
258 | if (ret <= 0) |
259 | return ret; | |
7b2d81d4 | 260 | |
ed6f6a50 ON |
261 | ret = verify_opcode(old_page, vaddr, &opcode); |
262 | if (ret <= 0) | |
263 | goto put_old; | |
264 | ||
2b144498 SD |
265 | ret = -ENOMEM; |
266 | new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr); | |
267 | if (!new_page) | |
9f92448c | 268 | goto put_old; |
2b144498 SD |
269 | |
270 | __SetPageUptodate(new_page); | |
271 | ||
2b144498 SD |
272 | /* copy the page now that we've got it stable */ |
273 | vaddr_old = kmap_atomic(old_page); | |
274 | vaddr_new = kmap_atomic(new_page); | |
275 | ||
276 | memcpy(vaddr_new, vaddr_old, PAGE_SIZE); | |
d9c4a30e | 277 | memcpy(vaddr_new + (vaddr & ~PAGE_MASK), &opcode, UPROBE_SWBP_INSN_SIZE); |
2b144498 SD |
278 | |
279 | kunmap_atomic(vaddr_new); | |
280 | kunmap_atomic(vaddr_old); | |
281 | ||
282 | ret = anon_vma_prepare(vma); | |
283 | if (ret) | |
9f92448c | 284 | goto put_new; |
2b144498 | 285 | |
c517ee74 | 286 | ret = __replace_page(vma, vaddr, old_page, new_page); |
2b144498 | 287 | |
9f92448c | 288 | put_new: |
2b144498 | 289 | page_cache_release(new_page); |
9f92448c | 290 | put_old: |
7b2d81d4 IM |
291 | put_page(old_page); |
292 | ||
5323ce71 ON |
293 | if (unlikely(ret == -EAGAIN)) |
294 | goto retry; | |
2b144498 SD |
295 | return ret; |
296 | } | |
297 | ||
2b144498 | 298 | /** |
5cb4ac3a | 299 | * set_swbp - store breakpoint at a given address. |
e3343e6a | 300 | * @auprobe: arch specific probepoint information. |
2b144498 | 301 | * @mm: the probed process address space. |
2b144498 SD |
302 | * @vaddr: the virtual address to insert the opcode. |
303 | * | |
304 | * For mm @mm, store the breakpoint instruction at @vaddr. | |
305 | * Return 0 (success) or a negative errno. | |
306 | */ | |
5cb4ac3a | 307 | int __weak set_swbp(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) |
2b144498 | 308 | { |
cceb55aa | 309 | return write_opcode(mm, vaddr, UPROBE_SWBP_INSN); |
2b144498 SD |
310 | } |
311 | ||
312 | /** | |
313 | * set_orig_insn - Restore the original instruction. | |
314 | * @mm: the probed process address space. | |
e3343e6a | 315 | * @auprobe: arch specific probepoint information. |
2b144498 | 316 | * @vaddr: the virtual address to insert the opcode. |
2b144498 SD |
317 | * |
318 | * For mm @mm, restore the original opcode (opcode) at @vaddr. | |
319 | * Return 0 (success) or a negative errno. | |
320 | */ | |
7b2d81d4 | 321 | int __weak |
ded86e7c | 322 | set_orig_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long vaddr) |
2b144498 | 323 | { |
cceb55aa | 324 | return write_opcode(mm, vaddr, *(uprobe_opcode_t *)auprobe->insn); |
2b144498 SD |
325 | } |
326 | ||
327 | static int match_uprobe(struct uprobe *l, struct uprobe *r) | |
328 | { | |
329 | if (l->inode < r->inode) | |
330 | return -1; | |
7b2d81d4 | 331 | |
2b144498 SD |
332 | if (l->inode > r->inode) |
333 | return 1; | |
2b144498 | 334 | |
7b2d81d4 IM |
335 | if (l->offset < r->offset) |
336 | return -1; | |
337 | ||
338 | if (l->offset > r->offset) | |
339 | return 1; | |
2b144498 SD |
340 | |
341 | return 0; | |
342 | } | |
343 | ||
344 | static struct uprobe *__find_uprobe(struct inode *inode, loff_t offset) | |
345 | { | |
346 | struct uprobe u = { .inode = inode, .offset = offset }; | |
347 | struct rb_node *n = uprobes_tree.rb_node; | |
348 | struct uprobe *uprobe; | |
349 | int match; | |
350 | ||
351 | while (n) { | |
352 | uprobe = rb_entry(n, struct uprobe, rb_node); | |
353 | match = match_uprobe(&u, uprobe); | |
354 | if (!match) { | |
355 | atomic_inc(&uprobe->ref); | |
356 | return uprobe; | |
357 | } | |
7b2d81d4 | 358 | |
2b144498 SD |
359 | if (match < 0) |
360 | n = n->rb_left; | |
361 | else | |
362 | n = n->rb_right; | |
363 | } | |
364 | return NULL; | |
365 | } | |
366 | ||
367 | /* | |
368 | * Find a uprobe corresponding to a given inode:offset | |
369 | * Acquires uprobes_treelock | |
370 | */ | |
371 | static struct uprobe *find_uprobe(struct inode *inode, loff_t offset) | |
372 | { | |
373 | struct uprobe *uprobe; | |
2b144498 | 374 | |
6f47caa0 | 375 | spin_lock(&uprobes_treelock); |
2b144498 | 376 | uprobe = __find_uprobe(inode, offset); |
6f47caa0 | 377 | spin_unlock(&uprobes_treelock); |
7b2d81d4 | 378 | |
2b144498 SD |
379 | return uprobe; |
380 | } | |
381 | ||
382 | static struct uprobe *__insert_uprobe(struct uprobe *uprobe) | |
383 | { | |
384 | struct rb_node **p = &uprobes_tree.rb_node; | |
385 | struct rb_node *parent = NULL; | |
386 | struct uprobe *u; | |
387 | int match; | |
388 | ||
389 | while (*p) { | |
390 | parent = *p; | |
391 | u = rb_entry(parent, struct uprobe, rb_node); | |
392 | match = match_uprobe(uprobe, u); | |
393 | if (!match) { | |
394 | atomic_inc(&u->ref); | |
395 | return u; | |
396 | } | |
397 | ||
398 | if (match < 0) | |
399 | p = &parent->rb_left; | |
400 | else | |
401 | p = &parent->rb_right; | |
402 | ||
403 | } | |
7b2d81d4 | 404 | |
2b144498 SD |
405 | u = NULL; |
406 | rb_link_node(&uprobe->rb_node, parent, p); | |
407 | rb_insert_color(&uprobe->rb_node, &uprobes_tree); | |
408 | /* get access + creation ref */ | |
409 | atomic_set(&uprobe->ref, 2); | |
7b2d81d4 | 410 | |
2b144498 SD |
411 | return u; |
412 | } | |
413 | ||
414 | /* | |
7b2d81d4 | 415 | * Acquire uprobes_treelock. |
2b144498 SD |
416 | * Matching uprobe already exists in rbtree; |
417 | * increment (access refcount) and return the matching uprobe. | |
418 | * | |
419 | * No matching uprobe; insert the uprobe in rb_tree; | |
420 | * get a double refcount (access + creation) and return NULL. | |
421 | */ | |
422 | static struct uprobe *insert_uprobe(struct uprobe *uprobe) | |
423 | { | |
2b144498 SD |
424 | struct uprobe *u; |
425 | ||
6f47caa0 | 426 | spin_lock(&uprobes_treelock); |
2b144498 | 427 | u = __insert_uprobe(uprobe); |
6f47caa0 | 428 | spin_unlock(&uprobes_treelock); |
7b2d81d4 | 429 | |
0326f5a9 | 430 | /* For now assume that the instruction need not be single-stepped */ |
71434f2f | 431 | __set_bit(UPROBE_SKIP_SSTEP, &uprobe->flags); |
0326f5a9 | 432 | |
2b144498 SD |
433 | return u; |
434 | } | |
435 | ||
436 | static void put_uprobe(struct uprobe *uprobe) | |
437 | { | |
438 | if (atomic_dec_and_test(&uprobe->ref)) | |
439 | kfree(uprobe); | |
440 | } | |
441 | ||
442 | static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset) | |
443 | { | |
444 | struct uprobe *uprobe, *cur_uprobe; | |
445 | ||
446 | uprobe = kzalloc(sizeof(struct uprobe), GFP_KERNEL); | |
447 | if (!uprobe) | |
448 | return NULL; | |
449 | ||
450 | uprobe->inode = igrab(inode); | |
451 | uprobe->offset = offset; | |
452 | init_rwsem(&uprobe->consumer_rwsem); | |
4710f05f | 453 | mutex_init(&uprobe->copy_mutex); |
2b144498 SD |
454 | |
455 | /* add to uprobes_tree, sorted on inode:offset */ | |
456 | cur_uprobe = insert_uprobe(uprobe); | |
457 | ||
458 | /* a uprobe exists for this inode:offset combination */ | |
459 | if (cur_uprobe) { | |
460 | kfree(uprobe); | |
461 | uprobe = cur_uprobe; | |
462 | iput(inode); | |
7b2d81d4 | 463 | } else { |
2b144498 | 464 | atomic_inc(&uprobe_events); |
7b2d81d4 IM |
465 | } |
466 | ||
2b144498 SD |
467 | return uprobe; |
468 | } | |
469 | ||
0326f5a9 SD |
470 | static void handler_chain(struct uprobe *uprobe, struct pt_regs *regs) |
471 | { | |
472 | struct uprobe_consumer *uc; | |
473 | ||
71434f2f | 474 | if (!test_bit(UPROBE_RUN_HANDLER, &uprobe->flags)) |
0326f5a9 SD |
475 | return; |
476 | ||
477 | down_read(&uprobe->consumer_rwsem); | |
478 | for (uc = uprobe->consumers; uc; uc = uc->next) { | |
479 | if (!uc->filter || uc->filter(uc, current)) | |
480 | uc->handler(uc, regs); | |
481 | } | |
482 | up_read(&uprobe->consumer_rwsem); | |
483 | } | |
484 | ||
2b144498 | 485 | /* Returns the previous consumer */ |
7b2d81d4 | 486 | static struct uprobe_consumer * |
e3343e6a | 487 | consumer_add(struct uprobe *uprobe, struct uprobe_consumer *uc) |
2b144498 SD |
488 | { |
489 | down_write(&uprobe->consumer_rwsem); | |
e3343e6a SD |
490 | uc->next = uprobe->consumers; |
491 | uprobe->consumers = uc; | |
2b144498 | 492 | up_write(&uprobe->consumer_rwsem); |
7b2d81d4 | 493 | |
e3343e6a | 494 | return uc->next; |
2b144498 SD |
495 | } |
496 | ||
497 | /* | |
e3343e6a SD |
498 | * For uprobe @uprobe, delete the consumer @uc. |
499 | * Return true if the @uc is deleted successfully | |
2b144498 SD |
500 | * or return false. |
501 | */ | |
e3343e6a | 502 | static bool consumer_del(struct uprobe *uprobe, struct uprobe_consumer *uc) |
2b144498 SD |
503 | { |
504 | struct uprobe_consumer **con; | |
505 | bool ret = false; | |
506 | ||
507 | down_write(&uprobe->consumer_rwsem); | |
508 | for (con = &uprobe->consumers; *con; con = &(*con)->next) { | |
e3343e6a SD |
509 | if (*con == uc) { |
510 | *con = uc->next; | |
2b144498 SD |
511 | ret = true; |
512 | break; | |
513 | } | |
514 | } | |
515 | up_write(&uprobe->consumer_rwsem); | |
7b2d81d4 | 516 | |
2b144498 SD |
517 | return ret; |
518 | } | |
519 | ||
e3343e6a | 520 | static int |
d436615e | 521 | __copy_insn(struct address_space *mapping, struct file *filp, char *insn, |
593609a5 | 522 | unsigned long nbytes, loff_t offset) |
2b144498 | 523 | { |
2b144498 SD |
524 | struct page *page; |
525 | void *vaddr; | |
593609a5 ON |
526 | unsigned long off; |
527 | pgoff_t idx; | |
2b144498 SD |
528 | |
529 | if (!filp) | |
530 | return -EINVAL; | |
531 | ||
cc359d18 ON |
532 | if (!mapping->a_ops->readpage) |
533 | return -EIO; | |
534 | ||
593609a5 ON |
535 | idx = offset >> PAGE_CACHE_SHIFT; |
536 | off = offset & ~PAGE_MASK; | |
2b144498 SD |
537 | |
538 | /* | |
539 | * Ensure that the page that has the original instruction is | |
540 | * populated and in page-cache. | |
541 | */ | |
542 | page = read_mapping_page(mapping, idx, filp); | |
543 | if (IS_ERR(page)) | |
544 | return PTR_ERR(page); | |
545 | ||
546 | vaddr = kmap_atomic(page); | |
593609a5 | 547 | memcpy(insn, vaddr + off, nbytes); |
2b144498 SD |
548 | kunmap_atomic(vaddr); |
549 | page_cache_release(page); | |
7b2d81d4 | 550 | |
2b144498 SD |
551 | return 0; |
552 | } | |
553 | ||
d436615e | 554 | static int copy_insn(struct uprobe *uprobe, struct file *filp) |
2b144498 SD |
555 | { |
556 | struct address_space *mapping; | |
2b144498 | 557 | unsigned long nbytes; |
7b2d81d4 | 558 | int bytes; |
2b144498 | 559 | |
d436615e | 560 | nbytes = PAGE_SIZE - (uprobe->offset & ~PAGE_MASK); |
2b144498 SD |
561 | mapping = uprobe->inode->i_mapping; |
562 | ||
563 | /* Instruction at end of binary; copy only available bytes */ | |
564 | if (uprobe->offset + MAX_UINSN_BYTES > uprobe->inode->i_size) | |
565 | bytes = uprobe->inode->i_size - uprobe->offset; | |
566 | else | |
567 | bytes = MAX_UINSN_BYTES; | |
568 | ||
569 | /* Instruction at the page-boundary; copy bytes in second page */ | |
570 | if (nbytes < bytes) { | |
fc36f595 ON |
571 | int err = __copy_insn(mapping, filp, uprobe->arch.insn + nbytes, |
572 | bytes - nbytes, uprobe->offset + nbytes); | |
573 | if (err) | |
574 | return err; | |
2b144498 SD |
575 | bytes = nbytes; |
576 | } | |
d436615e | 577 | return __copy_insn(mapping, filp, uprobe->arch.insn, bytes, uprobe->offset); |
2b144498 SD |
578 | } |
579 | ||
cb9a19fe ON |
580 | static int prepare_uprobe(struct uprobe *uprobe, struct file *file, |
581 | struct mm_struct *mm, unsigned long vaddr) | |
582 | { | |
583 | int ret = 0; | |
584 | ||
71434f2f | 585 | if (test_bit(UPROBE_COPY_INSN, &uprobe->flags)) |
cb9a19fe ON |
586 | return ret; |
587 | ||
4710f05f | 588 | mutex_lock(&uprobe->copy_mutex); |
71434f2f | 589 | if (test_bit(UPROBE_COPY_INSN, &uprobe->flags)) |
4710f05f ON |
590 | goto out; |
591 | ||
cb9a19fe ON |
592 | ret = copy_insn(uprobe, file); |
593 | if (ret) | |
594 | goto out; | |
595 | ||
596 | ret = -ENOTSUPP; | |
597 | if (is_swbp_insn((uprobe_opcode_t *)uprobe->arch.insn)) | |
598 | goto out; | |
599 | ||
600 | ret = arch_uprobe_analyze_insn(&uprobe->arch, mm, vaddr); | |
601 | if (ret) | |
602 | goto out; | |
603 | ||
604 | /* write_opcode() assumes we don't cross page boundary */ | |
605 | BUG_ON((uprobe->offset & ~PAGE_MASK) + | |
606 | UPROBE_SWBP_INSN_SIZE > PAGE_SIZE); | |
607 | ||
608 | smp_wmb(); /* pairs with rmb() in find_active_uprobe() */ | |
71434f2f | 609 | set_bit(UPROBE_COPY_INSN, &uprobe->flags); |
cb9a19fe ON |
610 | |
611 | out: | |
4710f05f ON |
612 | mutex_unlock(&uprobe->copy_mutex); |
613 | ||
cb9a19fe ON |
614 | return ret; |
615 | } | |
616 | ||
e3343e6a SD |
617 | static int |
618 | install_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, | |
816c03fb | 619 | struct vm_area_struct *vma, unsigned long vaddr) |
2b144498 | 620 | { |
f8ac4ec9 | 621 | bool first_uprobe; |
2b144498 SD |
622 | int ret; |
623 | ||
624 | /* | |
625 | * If probe is being deleted, unregister thread could be done with | |
626 | * the vma-rmap-walk through. Adding a probe now can be fatal since | |
627 | * nobody will be able to cleanup. Also we could be from fork or | |
628 | * mremap path, where the probe might have already been inserted. | |
629 | * Hence behave as if probe already existed. | |
630 | */ | |
631 | if (!uprobe->consumers) | |
78f74116 | 632 | return 0; |
2b144498 | 633 | |
cb9a19fe ON |
634 | ret = prepare_uprobe(uprobe, vma->vm_file, mm, vaddr); |
635 | if (ret) | |
636 | return ret; | |
682968e0 | 637 | |
f8ac4ec9 ON |
638 | /* |
639 | * set MMF_HAS_UPROBES in advance for uprobe_pre_sstep_notifier(), | |
640 | * the task can hit this breakpoint right after __replace_page(). | |
641 | */ | |
642 | first_uprobe = !test_bit(MMF_HAS_UPROBES, &mm->flags); | |
643 | if (first_uprobe) | |
644 | set_bit(MMF_HAS_UPROBES, &mm->flags); | |
645 | ||
816c03fb | 646 | ret = set_swbp(&uprobe->arch, mm, vaddr); |
9f68f672 ON |
647 | if (!ret) |
648 | clear_bit(MMF_RECALC_UPROBES, &mm->flags); | |
649 | else if (first_uprobe) | |
f8ac4ec9 | 650 | clear_bit(MMF_HAS_UPROBES, &mm->flags); |
2b144498 SD |
651 | |
652 | return ret; | |
653 | } | |
654 | ||
076a365b | 655 | static int |
816c03fb | 656 | remove_breakpoint(struct uprobe *uprobe, struct mm_struct *mm, unsigned long vaddr) |
2b144498 | 657 | { |
9f68f672 ON |
658 | /* can happen if uprobe_register() fails */ |
659 | if (!test_bit(MMF_HAS_UPROBES, &mm->flags)) | |
076a365b | 660 | return 0; |
9f68f672 ON |
661 | |
662 | set_bit(MMF_RECALC_UPROBES, &mm->flags); | |
076a365b | 663 | return set_orig_insn(&uprobe->arch, mm, vaddr); |
2b144498 SD |
664 | } |
665 | ||
0326f5a9 | 666 | /* |
778b032d ON |
667 | * There could be threads that have already hit the breakpoint. They |
668 | * will recheck the current insn and restart if find_uprobe() fails. | |
669 | * See find_active_uprobe(). | |
0326f5a9 | 670 | */ |
2b144498 SD |
671 | static void delete_uprobe(struct uprobe *uprobe) |
672 | { | |
6f47caa0 | 673 | spin_lock(&uprobes_treelock); |
2b144498 | 674 | rb_erase(&uprobe->rb_node, &uprobes_tree); |
6f47caa0 | 675 | spin_unlock(&uprobes_treelock); |
2b144498 SD |
676 | iput(uprobe->inode); |
677 | put_uprobe(uprobe); | |
678 | atomic_dec(&uprobe_events); | |
679 | } | |
680 | ||
26872090 ON |
681 | struct map_info { |
682 | struct map_info *next; | |
683 | struct mm_struct *mm; | |
816c03fb | 684 | unsigned long vaddr; |
26872090 ON |
685 | }; |
686 | ||
687 | static inline struct map_info *free_map_info(struct map_info *info) | |
2b144498 | 688 | { |
26872090 ON |
689 | struct map_info *next = info->next; |
690 | kfree(info); | |
691 | return next; | |
692 | } | |
693 | ||
694 | static struct map_info * | |
695 | build_map_info(struct address_space *mapping, loff_t offset, bool is_register) | |
696 | { | |
697 | unsigned long pgoff = offset >> PAGE_SHIFT; | |
2b144498 | 698 | struct vm_area_struct *vma; |
26872090 ON |
699 | struct map_info *curr = NULL; |
700 | struct map_info *prev = NULL; | |
701 | struct map_info *info; | |
702 | int more = 0; | |
2b144498 | 703 | |
26872090 ON |
704 | again: |
705 | mutex_lock(&mapping->i_mmap_mutex); | |
6b2dbba8 | 706 | vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) { |
2b144498 SD |
707 | if (!valid_vma(vma, is_register)) |
708 | continue; | |
709 | ||
7a5bfb66 ON |
710 | if (!prev && !more) { |
711 | /* | |
712 | * Needs GFP_NOWAIT to avoid i_mmap_mutex recursion through | |
713 | * reclaim. This is optimistic, no harm done if it fails. | |
714 | */ | |
715 | prev = kmalloc(sizeof(struct map_info), | |
716 | GFP_NOWAIT | __GFP_NOMEMALLOC | __GFP_NOWARN); | |
717 | if (prev) | |
718 | prev->next = NULL; | |
719 | } | |
26872090 ON |
720 | if (!prev) { |
721 | more++; | |
722 | continue; | |
2b144498 | 723 | } |
2b144498 | 724 | |
26872090 ON |
725 | if (!atomic_inc_not_zero(&vma->vm_mm->mm_users)) |
726 | continue; | |
7b2d81d4 | 727 | |
26872090 ON |
728 | info = prev; |
729 | prev = prev->next; | |
730 | info->next = curr; | |
731 | curr = info; | |
2b144498 | 732 | |
26872090 | 733 | info->mm = vma->vm_mm; |
57683f72 | 734 | info->vaddr = offset_to_vaddr(vma, offset); |
26872090 | 735 | } |
2b144498 SD |
736 | mutex_unlock(&mapping->i_mmap_mutex); |
737 | ||
26872090 ON |
738 | if (!more) |
739 | goto out; | |
740 | ||
741 | prev = curr; | |
742 | while (curr) { | |
743 | mmput(curr->mm); | |
744 | curr = curr->next; | |
745 | } | |
7b2d81d4 | 746 | |
26872090 ON |
747 | do { |
748 | info = kmalloc(sizeof(struct map_info), GFP_KERNEL); | |
749 | if (!info) { | |
750 | curr = ERR_PTR(-ENOMEM); | |
751 | goto out; | |
752 | } | |
753 | info->next = prev; | |
754 | prev = info; | |
755 | } while (--more); | |
756 | ||
757 | goto again; | |
758 | out: | |
759 | while (prev) | |
760 | prev = free_map_info(prev); | |
761 | return curr; | |
2b144498 SD |
762 | } |
763 | ||
764 | static int register_for_each_vma(struct uprobe *uprobe, bool is_register) | |
765 | { | |
26872090 ON |
766 | struct map_info *info; |
767 | int err = 0; | |
2b144498 | 768 | |
26872090 ON |
769 | info = build_map_info(uprobe->inode->i_mapping, |
770 | uprobe->offset, is_register); | |
771 | if (IS_ERR(info)) | |
772 | return PTR_ERR(info); | |
7b2d81d4 | 773 | |
26872090 ON |
774 | while (info) { |
775 | struct mm_struct *mm = info->mm; | |
776 | struct vm_area_struct *vma; | |
7b2d81d4 | 777 | |
076a365b | 778 | if (err && is_register) |
26872090 | 779 | goto free; |
7b2d81d4 | 780 | |
77fc4af1 | 781 | down_write(&mm->mmap_sem); |
f4d6dfe5 ON |
782 | vma = find_vma(mm, info->vaddr); |
783 | if (!vma || !valid_vma(vma, is_register) || | |
784 | vma->vm_file->f_mapping->host != uprobe->inode) | |
26872090 ON |
785 | goto unlock; |
786 | ||
f4d6dfe5 ON |
787 | if (vma->vm_start > info->vaddr || |
788 | vaddr_to_offset(vma, info->vaddr) != uprobe->offset) | |
26872090 | 789 | goto unlock; |
2b144498 | 790 | |
78f74116 | 791 | if (is_register) |
26872090 | 792 | err = install_breakpoint(uprobe, mm, vma, info->vaddr); |
78f74116 | 793 | else |
076a365b | 794 | err |= remove_breakpoint(uprobe, mm, info->vaddr); |
78f74116 | 795 | |
26872090 ON |
796 | unlock: |
797 | up_write(&mm->mmap_sem); | |
798 | free: | |
799 | mmput(mm); | |
800 | info = free_map_info(info); | |
2b144498 | 801 | } |
7b2d81d4 | 802 | |
26872090 | 803 | return err; |
2b144498 SD |
804 | } |
805 | ||
7b2d81d4 | 806 | static int __uprobe_register(struct uprobe *uprobe) |
2b144498 SD |
807 | { |
808 | return register_for_each_vma(uprobe, true); | |
809 | } | |
810 | ||
7b2d81d4 | 811 | static void __uprobe_unregister(struct uprobe *uprobe) |
2b144498 SD |
812 | { |
813 | if (!register_for_each_vma(uprobe, false)) | |
814 | delete_uprobe(uprobe); | |
815 | ||
816 | /* TODO : cant unregister? schedule a worker thread */ | |
817 | } | |
818 | ||
819 | /* | |
7b2d81d4 | 820 | * uprobe_register - register a probe |
2b144498 SD |
821 | * @inode: the file in which the probe has to be placed. |
822 | * @offset: offset from the start of the file. | |
e3343e6a | 823 | * @uc: information on howto handle the probe.. |
2b144498 | 824 | * |
7b2d81d4 | 825 | * Apart from the access refcount, uprobe_register() takes a creation |
2b144498 SD |
826 | * refcount (thro alloc_uprobe) if and only if this @uprobe is getting |
827 | * inserted into the rbtree (i.e first consumer for a @inode:@offset | |
7b2d81d4 | 828 | * tuple). Creation refcount stops uprobe_unregister from freeing the |
2b144498 | 829 | * @uprobe even before the register operation is complete. Creation |
e3343e6a | 830 | * refcount is released when the last @uc for the @uprobe |
2b144498 SD |
831 | * unregisters. |
832 | * | |
833 | * Return errno if it cannot successully install probes | |
834 | * else return 0 (success) | |
835 | */ | |
e3343e6a | 836 | int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) |
2b144498 SD |
837 | { |
838 | struct uprobe *uprobe; | |
7b2d81d4 | 839 | int ret; |
2b144498 | 840 | |
e3343e6a | 841 | if (!inode || !uc || uc->next) |
7b2d81d4 | 842 | return -EINVAL; |
2b144498 SD |
843 | |
844 | if (offset > i_size_read(inode)) | |
7b2d81d4 | 845 | return -EINVAL; |
2b144498 SD |
846 | |
847 | ret = 0; | |
848 | mutex_lock(uprobes_hash(inode)); | |
849 | uprobe = alloc_uprobe(inode, offset); | |
7b2d81d4 | 850 | |
a5f658b7 ON |
851 | if (!uprobe) { |
852 | ret = -ENOMEM; | |
853 | } else if (!consumer_add(uprobe, uc)) { | |
7b2d81d4 | 854 | ret = __uprobe_register(uprobe); |
2b144498 SD |
855 | if (ret) { |
856 | uprobe->consumers = NULL; | |
7b2d81d4 IM |
857 | __uprobe_unregister(uprobe); |
858 | } else { | |
71434f2f | 859 | set_bit(UPROBE_RUN_HANDLER, &uprobe->flags); |
7b2d81d4 | 860 | } |
2b144498 SD |
861 | } |
862 | ||
863 | mutex_unlock(uprobes_hash(inode)); | |
6d1d8dfa SAS |
864 | if (uprobe) |
865 | put_uprobe(uprobe); | |
2b144498 SD |
866 | |
867 | return ret; | |
868 | } | |
869 | ||
870 | /* | |
7b2d81d4 | 871 | * uprobe_unregister - unregister a already registered probe. |
2b144498 SD |
872 | * @inode: the file in which the probe has to be removed. |
873 | * @offset: offset from the start of the file. | |
e3343e6a | 874 | * @uc: identify which probe if multiple probes are colocated. |
2b144498 | 875 | */ |
e3343e6a | 876 | void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *uc) |
2b144498 | 877 | { |
7b2d81d4 | 878 | struct uprobe *uprobe; |
2b144498 | 879 | |
e3343e6a | 880 | if (!inode || !uc) |
2b144498 SD |
881 | return; |
882 | ||
883 | uprobe = find_uprobe(inode, offset); | |
884 | if (!uprobe) | |
885 | return; | |
886 | ||
887 | mutex_lock(uprobes_hash(inode)); | |
2b144498 | 888 | |
e3343e6a | 889 | if (consumer_del(uprobe, uc)) { |
7b2d81d4 IM |
890 | if (!uprobe->consumers) { |
891 | __uprobe_unregister(uprobe); | |
71434f2f | 892 | clear_bit(UPROBE_RUN_HANDLER, &uprobe->flags); |
7b2d81d4 | 893 | } |
2b144498 SD |
894 | } |
895 | ||
2b144498 SD |
896 | mutex_unlock(uprobes_hash(inode)); |
897 | if (uprobe) | |
898 | put_uprobe(uprobe); | |
899 | } | |
900 | ||
891c3970 ON |
901 | static struct rb_node * |
902 | find_node_in_range(struct inode *inode, loff_t min, loff_t max) | |
2b144498 | 903 | { |
2b144498 | 904 | struct rb_node *n = uprobes_tree.rb_node; |
2b144498 SD |
905 | |
906 | while (n) { | |
891c3970 | 907 | struct uprobe *u = rb_entry(n, struct uprobe, rb_node); |
2b144498 | 908 | |
891c3970 | 909 | if (inode < u->inode) { |
2b144498 | 910 | n = n->rb_left; |
891c3970 | 911 | } else if (inode > u->inode) { |
2b144498 | 912 | n = n->rb_right; |
891c3970 ON |
913 | } else { |
914 | if (max < u->offset) | |
915 | n = n->rb_left; | |
916 | else if (min > u->offset) | |
917 | n = n->rb_right; | |
918 | else | |
919 | break; | |
920 | } | |
2b144498 | 921 | } |
7b2d81d4 | 922 | |
891c3970 | 923 | return n; |
2b144498 SD |
924 | } |
925 | ||
926 | /* | |
891c3970 | 927 | * For a given range in vma, build a list of probes that need to be inserted. |
2b144498 | 928 | */ |
891c3970 ON |
929 | static void build_probe_list(struct inode *inode, |
930 | struct vm_area_struct *vma, | |
931 | unsigned long start, unsigned long end, | |
932 | struct list_head *head) | |
2b144498 | 933 | { |
891c3970 | 934 | loff_t min, max; |
891c3970 ON |
935 | struct rb_node *n, *t; |
936 | struct uprobe *u; | |
7b2d81d4 | 937 | |
891c3970 | 938 | INIT_LIST_HEAD(head); |
cb113b47 | 939 | min = vaddr_to_offset(vma, start); |
891c3970 | 940 | max = min + (end - start) - 1; |
2b144498 | 941 | |
6f47caa0 | 942 | spin_lock(&uprobes_treelock); |
891c3970 ON |
943 | n = find_node_in_range(inode, min, max); |
944 | if (n) { | |
945 | for (t = n; t; t = rb_prev(t)) { | |
946 | u = rb_entry(t, struct uprobe, rb_node); | |
947 | if (u->inode != inode || u->offset < min) | |
948 | break; | |
949 | list_add(&u->pending_list, head); | |
950 | atomic_inc(&u->ref); | |
951 | } | |
952 | for (t = n; (t = rb_next(t)); ) { | |
953 | u = rb_entry(t, struct uprobe, rb_node); | |
954 | if (u->inode != inode || u->offset > max) | |
955 | break; | |
956 | list_add(&u->pending_list, head); | |
957 | atomic_inc(&u->ref); | |
958 | } | |
2b144498 | 959 | } |
6f47caa0 | 960 | spin_unlock(&uprobes_treelock); |
2b144498 SD |
961 | } |
962 | ||
963 | /* | |
5e5be71a | 964 | * Called from mmap_region/vma_adjust with mm->mmap_sem acquired. |
2b144498 | 965 | * |
5e5be71a ON |
966 | * Currently we ignore all errors and always return 0, the callers |
967 | * can't handle the failure anyway. | |
2b144498 | 968 | */ |
7b2d81d4 | 969 | int uprobe_mmap(struct vm_area_struct *vma) |
2b144498 SD |
970 | { |
971 | struct list_head tmp_list; | |
665605a2 | 972 | struct uprobe *uprobe, *u; |
2b144498 | 973 | struct inode *inode; |
2b144498 SD |
974 | |
975 | if (!atomic_read(&uprobe_events) || !valid_vma(vma, true)) | |
7b2d81d4 | 976 | return 0; |
2b144498 SD |
977 | |
978 | inode = vma->vm_file->f_mapping->host; | |
979 | if (!inode) | |
7b2d81d4 | 980 | return 0; |
2b144498 | 981 | |
2b144498 | 982 | mutex_lock(uprobes_mmap_hash(inode)); |
891c3970 | 983 | build_probe_list(inode, vma, vma->vm_start, vma->vm_end, &tmp_list); |
7b2d81d4 | 984 | |
665605a2 | 985 | list_for_each_entry_safe(uprobe, u, &tmp_list, pending_list) { |
5e5be71a | 986 | if (!fatal_signal_pending(current)) { |
57683f72 | 987 | unsigned long vaddr = offset_to_vaddr(vma, uprobe->offset); |
5e5be71a | 988 | install_breakpoint(uprobe, vma->vm_mm, vma, vaddr); |
2b144498 SD |
989 | } |
990 | put_uprobe(uprobe); | |
991 | } | |
2b144498 SD |
992 | mutex_unlock(uprobes_mmap_hash(inode)); |
993 | ||
5e5be71a | 994 | return 0; |
2b144498 SD |
995 | } |
996 | ||
9f68f672 ON |
997 | static bool |
998 | vma_has_uprobes(struct vm_area_struct *vma, unsigned long start, unsigned long end) | |
999 | { | |
1000 | loff_t min, max; | |
1001 | struct inode *inode; | |
1002 | struct rb_node *n; | |
1003 | ||
1004 | inode = vma->vm_file->f_mapping->host; | |
1005 | ||
1006 | min = vaddr_to_offset(vma, start); | |
1007 | max = min + (end - start) - 1; | |
1008 | ||
1009 | spin_lock(&uprobes_treelock); | |
1010 | n = find_node_in_range(inode, min, max); | |
1011 | spin_unlock(&uprobes_treelock); | |
1012 | ||
1013 | return !!n; | |
1014 | } | |
1015 | ||
682968e0 SD |
1016 | /* |
1017 | * Called in context of a munmap of a vma. | |
1018 | */ | |
cbc91f71 | 1019 | void uprobe_munmap(struct vm_area_struct *vma, unsigned long start, unsigned long end) |
682968e0 | 1020 | { |
682968e0 SD |
1021 | if (!atomic_read(&uprobe_events) || !valid_vma(vma, false)) |
1022 | return; | |
1023 | ||
2fd611a9 ON |
1024 | if (!atomic_read(&vma->vm_mm->mm_users)) /* called by mmput() ? */ |
1025 | return; | |
1026 | ||
9f68f672 ON |
1027 | if (!test_bit(MMF_HAS_UPROBES, &vma->vm_mm->flags) || |
1028 | test_bit(MMF_RECALC_UPROBES, &vma->vm_mm->flags)) | |
f8ac4ec9 ON |
1029 | return; |
1030 | ||
9f68f672 ON |
1031 | if (vma_has_uprobes(vma, start, end)) |
1032 | set_bit(MMF_RECALC_UPROBES, &vma->vm_mm->flags); | |
682968e0 SD |
1033 | } |
1034 | ||
d4b3b638 SD |
1035 | /* Slot allocation for XOL */ |
1036 | static int xol_add_vma(struct xol_area *area) | |
1037 | { | |
1038 | struct mm_struct *mm; | |
1039 | int ret; | |
1040 | ||
1041 | area->page = alloc_page(GFP_HIGHUSER); | |
1042 | if (!area->page) | |
1043 | return -ENOMEM; | |
1044 | ||
1045 | ret = -EALREADY; | |
1046 | mm = current->mm; | |
1047 | ||
1048 | down_write(&mm->mmap_sem); | |
1049 | if (mm->uprobes_state.xol_area) | |
1050 | goto fail; | |
1051 | ||
1052 | ret = -ENOMEM; | |
1053 | ||
1054 | /* Try to map as high as possible, this is only a hint. */ | |
1055 | area->vaddr = get_unmapped_area(NULL, TASK_SIZE - PAGE_SIZE, PAGE_SIZE, 0, 0); | |
1056 | if (area->vaddr & ~PAGE_MASK) { | |
1057 | ret = area->vaddr; | |
1058 | goto fail; | |
1059 | } | |
1060 | ||
1061 | ret = install_special_mapping(mm, area->vaddr, PAGE_SIZE, | |
1062 | VM_EXEC|VM_MAYEXEC|VM_DONTCOPY|VM_IO, &area->page); | |
1063 | if (ret) | |
1064 | goto fail; | |
1065 | ||
1066 | smp_wmb(); /* pairs with get_xol_area() */ | |
1067 | mm->uprobes_state.xol_area = area; | |
1068 | ret = 0; | |
1069 | ||
1070 | fail: | |
1071 | up_write(&mm->mmap_sem); | |
1072 | if (ret) | |
1073 | __free_page(area->page); | |
1074 | ||
1075 | return ret; | |
1076 | } | |
1077 | ||
1078 | static struct xol_area *get_xol_area(struct mm_struct *mm) | |
1079 | { | |
1080 | struct xol_area *area; | |
1081 | ||
1082 | area = mm->uprobes_state.xol_area; | |
1083 | smp_read_barrier_depends(); /* pairs with wmb in xol_add_vma() */ | |
1084 | ||
1085 | return area; | |
1086 | } | |
1087 | ||
1088 | /* | |
1089 | * xol_alloc_area - Allocate process's xol_area. | |
1090 | * This area will be used for storing instructions for execution out of | |
1091 | * line. | |
1092 | * | |
1093 | * Returns the allocated area or NULL. | |
1094 | */ | |
1095 | static struct xol_area *xol_alloc_area(void) | |
1096 | { | |
1097 | struct xol_area *area; | |
1098 | ||
1099 | area = kzalloc(sizeof(*area), GFP_KERNEL); | |
1100 | if (unlikely(!area)) | |
1101 | return NULL; | |
1102 | ||
1103 | area->bitmap = kzalloc(BITS_TO_LONGS(UINSNS_PER_PAGE) * sizeof(long), GFP_KERNEL); | |
1104 | ||
1105 | if (!area->bitmap) | |
1106 | goto fail; | |
1107 | ||
1108 | init_waitqueue_head(&area->wq); | |
1109 | if (!xol_add_vma(area)) | |
1110 | return area; | |
1111 | ||
1112 | fail: | |
1113 | kfree(area->bitmap); | |
1114 | kfree(area); | |
1115 | ||
1116 | return get_xol_area(current->mm); | |
1117 | } | |
1118 | ||
1119 | /* | |
1120 | * uprobe_clear_state - Free the area allocated for slots. | |
1121 | */ | |
1122 | void uprobe_clear_state(struct mm_struct *mm) | |
1123 | { | |
1124 | struct xol_area *area = mm->uprobes_state.xol_area; | |
1125 | ||
1126 | if (!area) | |
1127 | return; | |
1128 | ||
1129 | put_page(area->page); | |
1130 | kfree(area->bitmap); | |
1131 | kfree(area); | |
1132 | } | |
1133 | ||
f8ac4ec9 ON |
1134 | void uprobe_dup_mmap(struct mm_struct *oldmm, struct mm_struct *newmm) |
1135 | { | |
61559a81 ON |
1136 | newmm->uprobes_state.xol_area = NULL; |
1137 | ||
9f68f672 | 1138 | if (test_bit(MMF_HAS_UPROBES, &oldmm->flags)) { |
f8ac4ec9 | 1139 | set_bit(MMF_HAS_UPROBES, &newmm->flags); |
9f68f672 ON |
1140 | /* unconditionally, dup_mmap() skips VM_DONTCOPY vmas */ |
1141 | set_bit(MMF_RECALC_UPROBES, &newmm->flags); | |
1142 | } | |
f8ac4ec9 ON |
1143 | } |
1144 | ||
d4b3b638 SD |
1145 | /* |
1146 | * - search for a free slot. | |
1147 | */ | |
1148 | static unsigned long xol_take_insn_slot(struct xol_area *area) | |
1149 | { | |
1150 | unsigned long slot_addr; | |
1151 | int slot_nr; | |
1152 | ||
1153 | do { | |
1154 | slot_nr = find_first_zero_bit(area->bitmap, UINSNS_PER_PAGE); | |
1155 | if (slot_nr < UINSNS_PER_PAGE) { | |
1156 | if (!test_and_set_bit(slot_nr, area->bitmap)) | |
1157 | break; | |
1158 | ||
1159 | slot_nr = UINSNS_PER_PAGE; | |
1160 | continue; | |
1161 | } | |
1162 | wait_event(area->wq, (atomic_read(&area->slot_count) < UINSNS_PER_PAGE)); | |
1163 | } while (slot_nr >= UINSNS_PER_PAGE); | |
1164 | ||
1165 | slot_addr = area->vaddr + (slot_nr * UPROBE_XOL_SLOT_BYTES); | |
1166 | atomic_inc(&area->slot_count); | |
1167 | ||
1168 | return slot_addr; | |
1169 | } | |
1170 | ||
1171 | /* | |
1172 | * xol_get_insn_slot - If was not allocated a slot, then | |
1173 | * allocate a slot. | |
1174 | * Returns the allocated slot address or 0. | |
1175 | */ | |
1176 | static unsigned long xol_get_insn_slot(struct uprobe *uprobe, unsigned long slot_addr) | |
1177 | { | |
1178 | struct xol_area *area; | |
1179 | unsigned long offset; | |
1180 | void *vaddr; | |
1181 | ||
1182 | area = get_xol_area(current->mm); | |
1183 | if (!area) { | |
1184 | area = xol_alloc_area(); | |
1185 | if (!area) | |
1186 | return 0; | |
1187 | } | |
1188 | current->utask->xol_vaddr = xol_take_insn_slot(area); | |
1189 | ||
1190 | /* | |
1191 | * Initialize the slot if xol_vaddr points to valid | |
1192 | * instruction slot. | |
1193 | */ | |
1194 | if (unlikely(!current->utask->xol_vaddr)) | |
1195 | return 0; | |
1196 | ||
1197 | current->utask->vaddr = slot_addr; | |
1198 | offset = current->utask->xol_vaddr & ~PAGE_MASK; | |
1199 | vaddr = kmap_atomic(area->page); | |
1200 | memcpy(vaddr + offset, uprobe->arch.insn, MAX_UINSN_BYTES); | |
1201 | kunmap_atomic(vaddr); | |
1202 | ||
1203 | return current->utask->xol_vaddr; | |
1204 | } | |
1205 | ||
1206 | /* | |
1207 | * xol_free_insn_slot - If slot was earlier allocated by | |
1208 | * @xol_get_insn_slot(), make the slot available for | |
1209 | * subsequent requests. | |
1210 | */ | |
1211 | static void xol_free_insn_slot(struct task_struct *tsk) | |
1212 | { | |
1213 | struct xol_area *area; | |
1214 | unsigned long vma_end; | |
1215 | unsigned long slot_addr; | |
1216 | ||
1217 | if (!tsk->mm || !tsk->mm->uprobes_state.xol_area || !tsk->utask) | |
1218 | return; | |
1219 | ||
1220 | slot_addr = tsk->utask->xol_vaddr; | |
1221 | ||
1222 | if (unlikely(!slot_addr || IS_ERR_VALUE(slot_addr))) | |
1223 | return; | |
1224 | ||
1225 | area = tsk->mm->uprobes_state.xol_area; | |
1226 | vma_end = area->vaddr + PAGE_SIZE; | |
1227 | if (area->vaddr <= slot_addr && slot_addr < vma_end) { | |
1228 | unsigned long offset; | |
1229 | int slot_nr; | |
1230 | ||
1231 | offset = slot_addr - area->vaddr; | |
1232 | slot_nr = offset / UPROBE_XOL_SLOT_BYTES; | |
1233 | if (slot_nr >= UINSNS_PER_PAGE) | |
1234 | return; | |
1235 | ||
1236 | clear_bit(slot_nr, area->bitmap); | |
1237 | atomic_dec(&area->slot_count); | |
1238 | if (waitqueue_active(&area->wq)) | |
1239 | wake_up(&area->wq); | |
1240 | ||
1241 | tsk->utask->xol_vaddr = 0; | |
1242 | } | |
1243 | } | |
1244 | ||
0326f5a9 SD |
1245 | /** |
1246 | * uprobe_get_swbp_addr - compute address of swbp given post-swbp regs | |
1247 | * @regs: Reflects the saved state of the task after it has hit a breakpoint | |
1248 | * instruction. | |
1249 | * Return the address of the breakpoint instruction. | |
1250 | */ | |
1251 | unsigned long __weak uprobe_get_swbp_addr(struct pt_regs *regs) | |
1252 | { | |
1253 | return instruction_pointer(regs) - UPROBE_SWBP_INSN_SIZE; | |
1254 | } | |
1255 | ||
1256 | /* | |
1257 | * Called with no locks held. | |
1258 | * Called in context of a exiting or a exec-ing thread. | |
1259 | */ | |
1260 | void uprobe_free_utask(struct task_struct *t) | |
1261 | { | |
1262 | struct uprobe_task *utask = t->utask; | |
1263 | ||
0326f5a9 SD |
1264 | if (!utask) |
1265 | return; | |
1266 | ||
1267 | if (utask->active_uprobe) | |
1268 | put_uprobe(utask->active_uprobe); | |
1269 | ||
d4b3b638 | 1270 | xol_free_insn_slot(t); |
0326f5a9 SD |
1271 | kfree(utask); |
1272 | t->utask = NULL; | |
1273 | } | |
1274 | ||
1275 | /* | |
1276 | * Called in context of a new clone/fork from copy_process. | |
1277 | */ | |
1278 | void uprobe_copy_process(struct task_struct *t) | |
1279 | { | |
1280 | t->utask = NULL; | |
0326f5a9 SD |
1281 | } |
1282 | ||
1283 | /* | |
1284 | * Allocate a uprobe_task object for the task. | |
1285 | * Called when the thread hits a breakpoint for the first time. | |
1286 | * | |
1287 | * Returns: | |
1288 | * - pointer to new uprobe_task on success | |
1289 | * - NULL otherwise | |
1290 | */ | |
1291 | static struct uprobe_task *add_utask(void) | |
1292 | { | |
1293 | struct uprobe_task *utask; | |
1294 | ||
1295 | utask = kzalloc(sizeof *utask, GFP_KERNEL); | |
1296 | if (unlikely(!utask)) | |
1297 | return NULL; | |
1298 | ||
0326f5a9 SD |
1299 | current->utask = utask; |
1300 | return utask; | |
1301 | } | |
1302 | ||
1303 | /* Prepare to single-step probed instruction out of line. */ | |
1304 | static int | |
1305 | pre_ssout(struct uprobe *uprobe, struct pt_regs *regs, unsigned long vaddr) | |
1306 | { | |
d4b3b638 SD |
1307 | if (xol_get_insn_slot(uprobe, vaddr) && !arch_uprobe_pre_xol(&uprobe->arch, regs)) |
1308 | return 0; | |
1309 | ||
0326f5a9 SD |
1310 | return -EFAULT; |
1311 | } | |
1312 | ||
1313 | /* | |
1314 | * If we are singlestepping, then ensure this thread is not connected to | |
1315 | * non-fatal signals until completion of singlestep. When xol insn itself | |
1316 | * triggers the signal, restart the original insn even if the task is | |
1317 | * already SIGKILL'ed (since coredump should report the correct ip). This | |
1318 | * is even more important if the task has a handler for SIGSEGV/etc, The | |
1319 | * _same_ instruction should be repeated again after return from the signal | |
1320 | * handler, and SSTEP can never finish in this case. | |
1321 | */ | |
1322 | bool uprobe_deny_signal(void) | |
1323 | { | |
1324 | struct task_struct *t = current; | |
1325 | struct uprobe_task *utask = t->utask; | |
1326 | ||
1327 | if (likely(!utask || !utask->active_uprobe)) | |
1328 | return false; | |
1329 | ||
1330 | WARN_ON_ONCE(utask->state != UTASK_SSTEP); | |
1331 | ||
1332 | if (signal_pending(t)) { | |
1333 | spin_lock_irq(&t->sighand->siglock); | |
1334 | clear_tsk_thread_flag(t, TIF_SIGPENDING); | |
1335 | spin_unlock_irq(&t->sighand->siglock); | |
1336 | ||
1337 | if (__fatal_signal_pending(t) || arch_uprobe_xol_was_trapped(t)) { | |
1338 | utask->state = UTASK_SSTEP_TRAPPED; | |
1339 | set_tsk_thread_flag(t, TIF_UPROBE); | |
1340 | set_tsk_thread_flag(t, TIF_NOTIFY_RESUME); | |
1341 | } | |
1342 | } | |
1343 | ||
1344 | return true; | |
1345 | } | |
1346 | ||
1347 | /* | |
1348 | * Avoid singlestepping the original instruction if the original instruction | |
1349 | * is a NOP or can be emulated. | |
1350 | */ | |
1351 | static bool can_skip_sstep(struct uprobe *uprobe, struct pt_regs *regs) | |
1352 | { | |
71434f2f | 1353 | if (test_bit(UPROBE_SKIP_SSTEP, &uprobe->flags)) { |
0578a970 ON |
1354 | if (arch_uprobe_skip_sstep(&uprobe->arch, regs)) |
1355 | return true; | |
71434f2f | 1356 | clear_bit(UPROBE_SKIP_SSTEP, &uprobe->flags); |
0578a970 | 1357 | } |
0326f5a9 SD |
1358 | return false; |
1359 | } | |
1360 | ||
499a4f3e ON |
1361 | static void mmf_recalc_uprobes(struct mm_struct *mm) |
1362 | { | |
1363 | struct vm_area_struct *vma; | |
1364 | ||
1365 | for (vma = mm->mmap; vma; vma = vma->vm_next) { | |
1366 | if (!valid_vma(vma, false)) | |
1367 | continue; | |
1368 | /* | |
1369 | * This is not strictly accurate, we can race with | |
1370 | * uprobe_unregister() and see the already removed | |
1371 | * uprobe if delete_uprobe() was not yet called. | |
1372 | */ | |
1373 | if (vma_has_uprobes(vma, vma->vm_start, vma->vm_end)) | |
1374 | return; | |
1375 | } | |
1376 | ||
1377 | clear_bit(MMF_HAS_UPROBES, &mm->flags); | |
1378 | } | |
1379 | ||
ec75fba9 ON |
1380 | static int is_swbp_at_addr(struct mm_struct *mm, unsigned long vaddr) |
1381 | { | |
1382 | struct page *page; | |
1383 | uprobe_opcode_t opcode; | |
1384 | int result; | |
1385 | ||
1386 | pagefault_disable(); | |
1387 | result = __copy_from_user_inatomic(&opcode, (void __user*)vaddr, | |
1388 | sizeof(opcode)); | |
1389 | pagefault_enable(); | |
1390 | ||
1391 | if (likely(result == 0)) | |
1392 | goto out; | |
1393 | ||
1394 | result = get_user_pages(NULL, mm, vaddr, 1, 0, 1, &page, NULL); | |
1395 | if (result < 0) | |
1396 | return result; | |
1397 | ||
1398 | copy_opcode(page, vaddr, &opcode); | |
1399 | put_page(page); | |
1400 | out: | |
1401 | return is_swbp_insn(&opcode); | |
1402 | } | |
1403 | ||
d790d346 | 1404 | static struct uprobe *find_active_uprobe(unsigned long bp_vaddr, int *is_swbp) |
0326f5a9 | 1405 | { |
3a9ea052 ON |
1406 | struct mm_struct *mm = current->mm; |
1407 | struct uprobe *uprobe = NULL; | |
0326f5a9 | 1408 | struct vm_area_struct *vma; |
0326f5a9 | 1409 | |
0326f5a9 SD |
1410 | down_read(&mm->mmap_sem); |
1411 | vma = find_vma(mm, bp_vaddr); | |
3a9ea052 ON |
1412 | if (vma && vma->vm_start <= bp_vaddr) { |
1413 | if (valid_vma(vma, false)) { | |
cb113b47 ON |
1414 | struct inode *inode = vma->vm_file->f_mapping->host; |
1415 | loff_t offset = vaddr_to_offset(vma, bp_vaddr); | |
0326f5a9 | 1416 | |
3a9ea052 ON |
1417 | uprobe = find_uprobe(inode, offset); |
1418 | } | |
d790d346 ON |
1419 | |
1420 | if (!uprobe) | |
1421 | *is_swbp = is_swbp_at_addr(mm, bp_vaddr); | |
1422 | } else { | |
1423 | *is_swbp = -EFAULT; | |
0326f5a9 | 1424 | } |
499a4f3e ON |
1425 | |
1426 | if (!uprobe && test_and_clear_bit(MMF_RECALC_UPROBES, &mm->flags)) | |
1427 | mmf_recalc_uprobes(mm); | |
0326f5a9 SD |
1428 | up_read(&mm->mmap_sem); |
1429 | ||
3a9ea052 ON |
1430 | return uprobe; |
1431 | } | |
1432 | ||
9d778782 SAS |
1433 | void __weak arch_uprobe_enable_step(struct arch_uprobe *arch) |
1434 | { | |
1435 | user_enable_single_step(current); | |
1436 | } | |
1437 | ||
1438 | void __weak arch_uprobe_disable_step(struct arch_uprobe *arch) | |
1439 | { | |
1440 | user_disable_single_step(current); | |
1441 | } | |
1442 | ||
3a9ea052 ON |
1443 | /* |
1444 | * Run handler and ask thread to singlestep. | |
1445 | * Ensure all non-fatal signals cannot interrupt thread while it singlesteps. | |
1446 | */ | |
1447 | static void handle_swbp(struct pt_regs *regs) | |
1448 | { | |
1449 | struct uprobe_task *utask; | |
1450 | struct uprobe *uprobe; | |
1451 | unsigned long bp_vaddr; | |
56bb4cf6 | 1452 | int uninitialized_var(is_swbp); |
3a9ea052 ON |
1453 | |
1454 | bp_vaddr = uprobe_get_swbp_addr(regs); | |
d790d346 | 1455 | uprobe = find_active_uprobe(bp_vaddr, &is_swbp); |
3a9ea052 | 1456 | |
0326f5a9 | 1457 | if (!uprobe) { |
56bb4cf6 ON |
1458 | if (is_swbp > 0) { |
1459 | /* No matching uprobe; signal SIGTRAP. */ | |
1460 | send_sig(SIGTRAP, current, 0); | |
1461 | } else { | |
1462 | /* | |
1463 | * Either we raced with uprobe_unregister() or we can't | |
1464 | * access this memory. The latter is only possible if | |
1465 | * another thread plays with our ->mm. In both cases | |
1466 | * we can simply restart. If this vma was unmapped we | |
1467 | * can pretend this insn was not executed yet and get | |
1468 | * the (correct) SIGSEGV after restart. | |
1469 | */ | |
1470 | instruction_pointer_set(regs, bp_vaddr); | |
1471 | } | |
0326f5a9 SD |
1472 | return; |
1473 | } | |
142b18dd ON |
1474 | /* |
1475 | * TODO: move copy_insn/etc into _register and remove this hack. | |
1476 | * After we hit the bp, _unregister + _register can install the | |
1477 | * new and not-yet-analyzed uprobe at the same address, restart. | |
1478 | */ | |
1479 | smp_rmb(); /* pairs with wmb() in install_breakpoint() */ | |
71434f2f | 1480 | if (unlikely(!test_bit(UPROBE_COPY_INSN, &uprobe->flags))) |
142b18dd | 1481 | goto restart; |
0326f5a9 SD |
1482 | |
1483 | utask = current->utask; | |
1484 | if (!utask) { | |
1485 | utask = add_utask(); | |
1486 | /* Cannot allocate; re-execute the instruction. */ | |
1487 | if (!utask) | |
0578a970 | 1488 | goto restart; |
0326f5a9 | 1489 | } |
746a9e6b | 1490 | |
0326f5a9 | 1491 | handler_chain(uprobe, regs); |
0578a970 ON |
1492 | if (can_skip_sstep(uprobe, regs)) |
1493 | goto out; | |
0326f5a9 | 1494 | |
0326f5a9 | 1495 | if (!pre_ssout(uprobe, regs, bp_vaddr)) { |
9d778782 | 1496 | arch_uprobe_enable_step(&uprobe->arch); |
746a9e6b ON |
1497 | utask->active_uprobe = uprobe; |
1498 | utask->state = UTASK_SSTEP; | |
0326f5a9 SD |
1499 | return; |
1500 | } | |
1501 | ||
0578a970 ON |
1502 | restart: |
1503 | /* | |
1504 | * cannot singlestep; cannot skip instruction; | |
1505 | * re-execute the instruction. | |
1506 | */ | |
1507 | instruction_pointer_set(regs, bp_vaddr); | |
1508 | out: | |
8bd87445 | 1509 | put_uprobe(uprobe); |
0326f5a9 SD |
1510 | } |
1511 | ||
1512 | /* | |
1513 | * Perform required fix-ups and disable singlestep. | |
1514 | * Allow pending signals to take effect. | |
1515 | */ | |
1516 | static void handle_singlestep(struct uprobe_task *utask, struct pt_regs *regs) | |
1517 | { | |
1518 | struct uprobe *uprobe; | |
1519 | ||
1520 | uprobe = utask->active_uprobe; | |
1521 | if (utask->state == UTASK_SSTEP_ACK) | |
1522 | arch_uprobe_post_xol(&uprobe->arch, regs); | |
1523 | else if (utask->state == UTASK_SSTEP_TRAPPED) | |
1524 | arch_uprobe_abort_xol(&uprobe->arch, regs); | |
1525 | else | |
1526 | WARN_ON_ONCE(1); | |
1527 | ||
9d778782 | 1528 | arch_uprobe_disable_step(&uprobe->arch); |
0326f5a9 SD |
1529 | put_uprobe(uprobe); |
1530 | utask->active_uprobe = NULL; | |
1531 | utask->state = UTASK_RUNNING; | |
d4b3b638 | 1532 | xol_free_insn_slot(current); |
0326f5a9 SD |
1533 | |
1534 | spin_lock_irq(¤t->sighand->siglock); | |
1535 | recalc_sigpending(); /* see uprobe_deny_signal() */ | |
1536 | spin_unlock_irq(¤t->sighand->siglock); | |
1537 | } | |
1538 | ||
1539 | /* | |
1b08e907 ON |
1540 | * On breakpoint hit, breakpoint notifier sets the TIF_UPROBE flag and |
1541 | * allows the thread to return from interrupt. After that handle_swbp() | |
1542 | * sets utask->active_uprobe. | |
0326f5a9 | 1543 | * |
1b08e907 ON |
1544 | * On singlestep exception, singlestep notifier sets the TIF_UPROBE flag |
1545 | * and allows the thread to return from interrupt. | |
0326f5a9 SD |
1546 | * |
1547 | * While returning to userspace, thread notices the TIF_UPROBE flag and calls | |
1548 | * uprobe_notify_resume(). | |
1549 | */ | |
1550 | void uprobe_notify_resume(struct pt_regs *regs) | |
1551 | { | |
1552 | struct uprobe_task *utask; | |
1553 | ||
db023ea5 ON |
1554 | clear_thread_flag(TIF_UPROBE); |
1555 | ||
0326f5a9 | 1556 | utask = current->utask; |
1b08e907 | 1557 | if (utask && utask->active_uprobe) |
0326f5a9 | 1558 | handle_singlestep(utask, regs); |
1b08e907 ON |
1559 | else |
1560 | handle_swbp(regs); | |
0326f5a9 SD |
1561 | } |
1562 | ||
1563 | /* | |
1564 | * uprobe_pre_sstep_notifier gets called from interrupt context as part of | |
1565 | * notifier mechanism. Set TIF_UPROBE flag and indicate breakpoint hit. | |
1566 | */ | |
1567 | int uprobe_pre_sstep_notifier(struct pt_regs *regs) | |
1568 | { | |
f8ac4ec9 | 1569 | if (!current->mm || !test_bit(MMF_HAS_UPROBES, ¤t->mm->flags)) |
0326f5a9 SD |
1570 | return 0; |
1571 | ||
0326f5a9 | 1572 | set_thread_flag(TIF_UPROBE); |
0326f5a9 SD |
1573 | return 1; |
1574 | } | |
1575 | ||
1576 | /* | |
1577 | * uprobe_post_sstep_notifier gets called in interrupt context as part of notifier | |
1578 | * mechanism. Set TIF_UPROBE flag and indicate completion of singlestep. | |
1579 | */ | |
1580 | int uprobe_post_sstep_notifier(struct pt_regs *regs) | |
1581 | { | |
1582 | struct uprobe_task *utask = current->utask; | |
1583 | ||
1584 | if (!current->mm || !utask || !utask->active_uprobe) | |
1585 | /* task is currently not uprobed */ | |
1586 | return 0; | |
1587 | ||
1588 | utask->state = UTASK_SSTEP_ACK; | |
1589 | set_thread_flag(TIF_UPROBE); | |
1590 | return 1; | |
1591 | } | |
1592 | ||
1593 | static struct notifier_block uprobe_exception_nb = { | |
1594 | .notifier_call = arch_uprobe_exception_notify, | |
1595 | .priority = INT_MAX-1, /* notified after kprobes, kgdb */ | |
1596 | }; | |
1597 | ||
2b144498 SD |
1598 | static int __init init_uprobes(void) |
1599 | { | |
1600 | int i; | |
1601 | ||
1602 | for (i = 0; i < UPROBES_HASH_SZ; i++) { | |
1603 | mutex_init(&uprobes_mutex[i]); | |
1604 | mutex_init(&uprobes_mmap_mutex[i]); | |
1605 | } | |
0326f5a9 SD |
1606 | |
1607 | return register_die_notifier(&uprobe_exception_nb); | |
2b144498 | 1608 | } |
0326f5a9 | 1609 | module_init(init_uprobes); |
2b144498 SD |
1610 | |
1611 | static void __exit exit_uprobes(void) | |
1612 | { | |
1613 | } | |
2b144498 | 1614 | module_exit(exit_uprobes); |