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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
5c9a8750 DV |
2 | #define pr_fmt(fmt) "kcov: " fmt |
3 | ||
36f05ae8 | 4 | #define DISABLE_BRANCH_PROFILING |
db862358 | 5 | #include <linux/atomic.h> |
5c9a8750 | 6 | #include <linux/compiler.h> |
db862358 KW |
7 | #include <linux/errno.h> |
8 | #include <linux/export.h> | |
5c9a8750 DV |
9 | #include <linux/types.h> |
10 | #include <linux/file.h> | |
11 | #include <linux/fs.h> | |
eec028c9 | 12 | #include <linux/hashtable.h> |
db862358 | 13 | #include <linux/init.h> |
5c9a8750 | 14 | #include <linux/mm.h> |
db862358 | 15 | #include <linux/preempt.h> |
5c9a8750 | 16 | #include <linux/printk.h> |
166ad0e1 | 17 | #include <linux/sched.h> |
5c9a8750 DV |
18 | #include <linux/slab.h> |
19 | #include <linux/spinlock.h> | |
20 | #include <linux/vmalloc.h> | |
21 | #include <linux/debugfs.h> | |
22 | #include <linux/uaccess.h> | |
23 | #include <linux/kcov.h> | |
39e07cb6 | 24 | #include <linux/refcount.h> |
eec028c9 | 25 | #include <linux/log2.h> |
4983f0ab | 26 | #include <asm/setup.h> |
5c9a8750 | 27 | |
eec028c9 AK |
28 | #define kcov_debug(fmt, ...) pr_debug("%s: " fmt, __func__, ##__VA_ARGS__) |
29 | ||
ded97d2c VC |
30 | /* Number of 64-bit words written per one comparison: */ |
31 | #define KCOV_WORDS_PER_CMP 4 | |
32 | ||
5c9a8750 DV |
33 | /* |
34 | * kcov descriptor (one per opened debugfs file). | |
35 | * State transitions of the descriptor: | |
36 | * - initial state after open() | |
37 | * - then there must be a single ioctl(KCOV_INIT_TRACE) call | |
38 | * - then, mmap() call (several calls are allowed but not useful) | |
ded97d2c VC |
39 | * - then, ioctl(KCOV_ENABLE, arg), where arg is |
40 | * KCOV_TRACE_PC - to trace only the PCs | |
41 | * or | |
42 | * KCOV_TRACE_CMP - to trace only the comparison operands | |
43 | * - then, ioctl(KCOV_DISABLE) to disable the task. | |
44 | * Enabling/disabling ioctls can be repeated (only one task a time allowed). | |
5c9a8750 DV |
45 | */ |
46 | struct kcov { | |
47 | /* | |
48 | * Reference counter. We keep one for: | |
49 | * - opened file descriptor | |
50 | * - task with enabled coverage (we can't unwire it from another task) | |
eec028c9 | 51 | * - each code section for remote coverage collection |
5c9a8750 | 52 | */ |
39e07cb6 | 53 | refcount_t refcount; |
5c9a8750 DV |
54 | /* The lock protects mode, size, area and t. */ |
55 | spinlock_t lock; | |
56 | enum kcov_mode mode; | |
eec028c9 AK |
57 | /* Size of arena (in long's). */ |
58 | unsigned int size; | |
5c9a8750 DV |
59 | /* Coverage buffer shared with user space. */ |
60 | void *area; | |
61 | /* Task for which we collect coverage, or NULL. */ | |
62 | struct task_struct *t; | |
eec028c9 AK |
63 | /* Collecting coverage from remote (background) threads. */ |
64 | bool remote; | |
65 | /* Size of remote area (in long's). */ | |
66 | unsigned int remote_size; | |
67 | /* | |
68 | * Sequence is incremented each time kcov is reenabled, used by | |
69 | * kcov_remote_stop(), see the comment there. | |
70 | */ | |
71 | int sequence; | |
5c9a8750 DV |
72 | }; |
73 | ||
eec028c9 AK |
74 | struct kcov_remote_area { |
75 | struct list_head list; | |
76 | unsigned int size; | |
77 | }; | |
78 | ||
79 | struct kcov_remote { | |
80 | u64 handle; | |
81 | struct kcov *kcov; | |
82 | struct hlist_node hnode; | |
83 | }; | |
84 | ||
85 | static DEFINE_SPINLOCK(kcov_remote_lock); | |
86 | static DEFINE_HASHTABLE(kcov_remote_map, 4); | |
87 | static struct list_head kcov_remote_areas = LIST_HEAD_INIT(kcov_remote_areas); | |
88 | ||
5ff3b30a AK |
89 | struct kcov_percpu_data { |
90 | void *irq_area; | |
d5d2c51f | 91 | local_lock_t lock; |
5ff3b30a AK |
92 | |
93 | unsigned int saved_mode; | |
94 | unsigned int saved_size; | |
95 | void *saved_area; | |
96 | struct kcov *saved_kcov; | |
97 | int saved_sequence; | |
98 | }; | |
99 | ||
d5d2c51f SAS |
100 | static DEFINE_PER_CPU(struct kcov_percpu_data, kcov_percpu_data) = { |
101 | .lock = INIT_LOCAL_LOCK(lock), | |
102 | }; | |
5ff3b30a | 103 | |
eec028c9 AK |
104 | /* Must be called with kcov_remote_lock locked. */ |
105 | static struct kcov_remote *kcov_remote_find(u64 handle) | |
106 | { | |
107 | struct kcov_remote *remote; | |
108 | ||
109 | hash_for_each_possible(kcov_remote_map, remote, hnode, handle) { | |
110 | if (remote->handle == handle) | |
111 | return remote; | |
112 | } | |
113 | return NULL; | |
114 | } | |
115 | ||
3c61df38 | 116 | /* Must be called with kcov_remote_lock locked. */ |
eec028c9 AK |
117 | static struct kcov_remote *kcov_remote_add(struct kcov *kcov, u64 handle) |
118 | { | |
119 | struct kcov_remote *remote; | |
120 | ||
121 | if (kcov_remote_find(handle)) | |
122 | return ERR_PTR(-EEXIST); | |
123 | remote = kmalloc(sizeof(*remote), GFP_ATOMIC); | |
124 | if (!remote) | |
125 | return ERR_PTR(-ENOMEM); | |
126 | remote->handle = handle; | |
127 | remote->kcov = kcov; | |
128 | hash_add(kcov_remote_map, &remote->hnode, handle); | |
129 | return remote; | |
130 | } | |
131 | ||
132 | /* Must be called with kcov_remote_lock locked. */ | |
133 | static struct kcov_remote_area *kcov_remote_area_get(unsigned int size) | |
134 | { | |
135 | struct kcov_remote_area *area; | |
136 | struct list_head *pos; | |
137 | ||
eec028c9 AK |
138 | list_for_each(pos, &kcov_remote_areas) { |
139 | area = list_entry(pos, struct kcov_remote_area, list); | |
140 | if (area->size == size) { | |
141 | list_del(&area->list); | |
eec028c9 AK |
142 | return area; |
143 | } | |
144 | } | |
eec028c9 AK |
145 | return NULL; |
146 | } | |
147 | ||
148 | /* Must be called with kcov_remote_lock locked. */ | |
149 | static void kcov_remote_area_put(struct kcov_remote_area *area, | |
150 | unsigned int size) | |
151 | { | |
eec028c9 AK |
152 | INIT_LIST_HEAD(&area->list); |
153 | area->size = size; | |
154 | list_add(&area->list, &kcov_remote_areas); | |
155 | } | |
156 | ||
903e8ff8 | 157 | static notrace bool check_kcov_mode(enum kcov_mode needed_mode, struct task_struct *t) |
5c9a8750 | 158 | { |
0ed557aa | 159 | unsigned int mode; |
5c9a8750 | 160 | |
5c9a8750 DV |
161 | /* |
162 | * We are interested in code coverage as a function of a syscall inputs, | |
5ff3b30a AK |
163 | * so we ignore code executed in interrupts, unless we are in a remote |
164 | * coverage collection section in a softirq. | |
5c9a8750 | 165 | */ |
5ff3b30a | 166 | if (!in_task() && !(in_serving_softirq() && t->kcov_softirq)) |
ded97d2c | 167 | return false; |
5c9a8750 | 168 | mode = READ_ONCE(t->kcov_mode); |
ded97d2c VC |
169 | /* |
170 | * There is some code that runs in interrupts but for which | |
171 | * in_interrupt() returns false (e.g. preempt_schedule_irq()). | |
172 | * READ_ONCE()/barrier() effectively provides load-acquire wrt | |
173 | * interrupts, there are paired barrier()/WRITE_ONCE() in | |
eec028c9 | 174 | * kcov_start(). |
ded97d2c VC |
175 | */ |
176 | barrier(); | |
177 | return mode == needed_mode; | |
178 | } | |
4983f0ab | 179 | |
903e8ff8 | 180 | static notrace unsigned long canonicalize_ip(unsigned long ip) |
ded97d2c | 181 | { |
4983f0ab | 182 | #ifdef CONFIG_RANDOMIZE_BASE |
ded97d2c | 183 | ip -= kaslr_offset(); |
4983f0ab | 184 | #endif |
ded97d2c VC |
185 | return ip; |
186 | } | |
5c9a8750 | 187 | |
ded97d2c VC |
188 | /* |
189 | * Entry point from instrumented code. | |
190 | * This is called once per basic-block/edge. | |
191 | */ | |
192 | void notrace __sanitizer_cov_trace_pc(void) | |
193 | { | |
194 | struct task_struct *t; | |
195 | unsigned long *area; | |
196 | unsigned long ip = canonicalize_ip(_RET_IP_); | |
197 | unsigned long pos; | |
198 | ||
199 | t = current; | |
200 | if (!check_kcov_mode(KCOV_MODE_TRACE_PC, t)) | |
201 | return; | |
202 | ||
203 | area = t->kcov_area; | |
204 | /* The first 64-bit word is the number of subsequent PCs. */ | |
205 | pos = READ_ONCE(area[0]) + 1; | |
206 | if (likely(pos < t->kcov_size)) { | |
207 | area[pos] = ip; | |
208 | WRITE_ONCE(area[0], pos); | |
5c9a8750 DV |
209 | } |
210 | } | |
211 | EXPORT_SYMBOL(__sanitizer_cov_trace_pc); | |
212 | ||
ded97d2c | 213 | #ifdef CONFIG_KCOV_ENABLE_COMPARISONS |
63472443 | 214 | static void notrace write_comp_data(u64 type, u64 arg1, u64 arg2, u64 ip) |
ded97d2c VC |
215 | { |
216 | struct task_struct *t; | |
217 | u64 *area; | |
218 | u64 count, start_index, end_pos, max_pos; | |
219 | ||
220 | t = current; | |
221 | if (!check_kcov_mode(KCOV_MODE_TRACE_CMP, t)) | |
222 | return; | |
223 | ||
224 | ip = canonicalize_ip(ip); | |
225 | ||
226 | /* | |
227 | * We write all comparison arguments and types as u64. | |
228 | * The buffer was allocated for t->kcov_size unsigned longs. | |
229 | */ | |
230 | area = (u64 *)t->kcov_area; | |
231 | max_pos = t->kcov_size * sizeof(unsigned long); | |
232 | ||
233 | count = READ_ONCE(area[0]); | |
234 | ||
235 | /* Every record is KCOV_WORDS_PER_CMP 64-bit words. */ | |
236 | start_index = 1 + count * KCOV_WORDS_PER_CMP; | |
237 | end_pos = (start_index + KCOV_WORDS_PER_CMP) * sizeof(u64); | |
238 | if (likely(end_pos <= max_pos)) { | |
239 | area[start_index] = type; | |
240 | area[start_index + 1] = arg1; | |
241 | area[start_index + 2] = arg2; | |
242 | area[start_index + 3] = ip; | |
243 | WRITE_ONCE(area[0], count + 1); | |
244 | } | |
245 | } | |
246 | ||
247 | void notrace __sanitizer_cov_trace_cmp1(u8 arg1, u8 arg2) | |
248 | { | |
249 | write_comp_data(KCOV_CMP_SIZE(0), arg1, arg2, _RET_IP_); | |
250 | } | |
251 | EXPORT_SYMBOL(__sanitizer_cov_trace_cmp1); | |
252 | ||
253 | void notrace __sanitizer_cov_trace_cmp2(u16 arg1, u16 arg2) | |
254 | { | |
255 | write_comp_data(KCOV_CMP_SIZE(1), arg1, arg2, _RET_IP_); | |
256 | } | |
257 | EXPORT_SYMBOL(__sanitizer_cov_trace_cmp2); | |
258 | ||
689d77f0 | 259 | void notrace __sanitizer_cov_trace_cmp4(u32 arg1, u32 arg2) |
ded97d2c VC |
260 | { |
261 | write_comp_data(KCOV_CMP_SIZE(2), arg1, arg2, _RET_IP_); | |
262 | } | |
263 | EXPORT_SYMBOL(__sanitizer_cov_trace_cmp4); | |
264 | ||
265 | void notrace __sanitizer_cov_trace_cmp8(u64 arg1, u64 arg2) | |
266 | { | |
267 | write_comp_data(KCOV_CMP_SIZE(3), arg1, arg2, _RET_IP_); | |
268 | } | |
269 | EXPORT_SYMBOL(__sanitizer_cov_trace_cmp8); | |
270 | ||
271 | void notrace __sanitizer_cov_trace_const_cmp1(u8 arg1, u8 arg2) | |
272 | { | |
273 | write_comp_data(KCOV_CMP_SIZE(0) | KCOV_CMP_CONST, arg1, arg2, | |
274 | _RET_IP_); | |
275 | } | |
276 | EXPORT_SYMBOL(__sanitizer_cov_trace_const_cmp1); | |
277 | ||
278 | void notrace __sanitizer_cov_trace_const_cmp2(u16 arg1, u16 arg2) | |
279 | { | |
280 | write_comp_data(KCOV_CMP_SIZE(1) | KCOV_CMP_CONST, arg1, arg2, | |
281 | _RET_IP_); | |
282 | } | |
283 | EXPORT_SYMBOL(__sanitizer_cov_trace_const_cmp2); | |
284 | ||
689d77f0 | 285 | void notrace __sanitizer_cov_trace_const_cmp4(u32 arg1, u32 arg2) |
ded97d2c VC |
286 | { |
287 | write_comp_data(KCOV_CMP_SIZE(2) | KCOV_CMP_CONST, arg1, arg2, | |
288 | _RET_IP_); | |
289 | } | |
290 | EXPORT_SYMBOL(__sanitizer_cov_trace_const_cmp4); | |
291 | ||
292 | void notrace __sanitizer_cov_trace_const_cmp8(u64 arg1, u64 arg2) | |
293 | { | |
294 | write_comp_data(KCOV_CMP_SIZE(3) | KCOV_CMP_CONST, arg1, arg2, | |
295 | _RET_IP_); | |
296 | } | |
297 | EXPORT_SYMBOL(__sanitizer_cov_trace_const_cmp8); | |
298 | ||
299 | void notrace __sanitizer_cov_trace_switch(u64 val, u64 *cases) | |
300 | { | |
301 | u64 i; | |
302 | u64 count = cases[0]; | |
303 | u64 size = cases[1]; | |
304 | u64 type = KCOV_CMP_CONST; | |
305 | ||
306 | switch (size) { | |
307 | case 8: | |
308 | type |= KCOV_CMP_SIZE(0); | |
309 | break; | |
310 | case 16: | |
311 | type |= KCOV_CMP_SIZE(1); | |
312 | break; | |
313 | case 32: | |
314 | type |= KCOV_CMP_SIZE(2); | |
315 | break; | |
316 | case 64: | |
317 | type |= KCOV_CMP_SIZE(3); | |
318 | break; | |
319 | default: | |
320 | return; | |
321 | } | |
322 | for (i = 0; i < count; i++) | |
323 | write_comp_data(type, cases[i + 2], val, _RET_IP_); | |
324 | } | |
325 | EXPORT_SYMBOL(__sanitizer_cov_trace_switch); | |
326 | #endif /* ifdef CONFIG_KCOV_ENABLE_COMPARISONS */ | |
327 | ||
76484b1c AK |
328 | static void kcov_start(struct task_struct *t, struct kcov *kcov, |
329 | unsigned int size, void *area, enum kcov_mode mode, | |
330 | int sequence) | |
eec028c9 AK |
331 | { |
332 | kcov_debug("t = %px, size = %u, area = %px\n", t, size, area); | |
76484b1c | 333 | t->kcov = kcov; |
eec028c9 AK |
334 | /* Cache in task struct for performance. */ |
335 | t->kcov_size = size; | |
336 | t->kcov_area = area; | |
eeb91f9a | 337 | t->kcov_sequence = sequence; |
eec028c9 AK |
338 | /* See comment in check_kcov_mode(). */ |
339 | barrier(); | |
340 | WRITE_ONCE(t->kcov_mode, mode); | |
eec028c9 AK |
341 | } |
342 | ||
343 | static void kcov_stop(struct task_struct *t) | |
344 | { | |
345 | WRITE_ONCE(t->kcov_mode, KCOV_MODE_DISABLED); | |
346 | barrier(); | |
76484b1c | 347 | t->kcov = NULL; |
eec028c9 AK |
348 | t->kcov_size = 0; |
349 | t->kcov_area = NULL; | |
350 | } | |
351 | ||
352 | static void kcov_task_reset(struct task_struct *t) | |
353 | { | |
354 | kcov_stop(t); | |
eec028c9 AK |
355 | t->kcov_sequence = 0; |
356 | t->kcov_handle = 0; | |
357 | } | |
358 | ||
359 | void kcov_task_init(struct task_struct *t) | |
360 | { | |
361 | kcov_task_reset(t); | |
362 | t->kcov_handle = current->kcov_handle; | |
363 | } | |
364 | ||
365 | static void kcov_reset(struct kcov *kcov) | |
366 | { | |
367 | kcov->t = NULL; | |
368 | kcov->mode = KCOV_MODE_INIT; | |
369 | kcov->remote = false; | |
370 | kcov->remote_size = 0; | |
371 | kcov->sequence++; | |
372 | } | |
373 | ||
374 | static void kcov_remote_reset(struct kcov *kcov) | |
375 | { | |
376 | int bkt; | |
377 | struct kcov_remote *remote; | |
378 | struct hlist_node *tmp; | |
5ff3b30a | 379 | unsigned long flags; |
eec028c9 | 380 | |
5ff3b30a | 381 | spin_lock_irqsave(&kcov_remote_lock, flags); |
eec028c9 AK |
382 | hash_for_each_safe(kcov_remote_map, bkt, tmp, remote, hnode) { |
383 | if (remote->kcov != kcov) | |
384 | continue; | |
eec028c9 AK |
385 | hash_del(&remote->hnode); |
386 | kfree(remote); | |
387 | } | |
388 | /* Do reset before unlock to prevent races with kcov_remote_start(). */ | |
389 | kcov_reset(kcov); | |
5ff3b30a | 390 | spin_unlock_irqrestore(&kcov_remote_lock, flags); |
eec028c9 AK |
391 | } |
392 | ||
393 | static void kcov_disable(struct task_struct *t, struct kcov *kcov) | |
394 | { | |
395 | kcov_task_reset(t); | |
396 | if (kcov->remote) | |
397 | kcov_remote_reset(kcov); | |
398 | else | |
399 | kcov_reset(kcov); | |
400 | } | |
401 | ||
5c9a8750 DV |
402 | static void kcov_get(struct kcov *kcov) |
403 | { | |
39e07cb6 | 404 | refcount_inc(&kcov->refcount); |
5c9a8750 DV |
405 | } |
406 | ||
407 | static void kcov_put(struct kcov *kcov) | |
408 | { | |
39e07cb6 | 409 | if (refcount_dec_and_test(&kcov->refcount)) { |
eec028c9 | 410 | kcov_remote_reset(kcov); |
5c9a8750 DV |
411 | vfree(kcov->area); |
412 | kfree(kcov); | |
413 | } | |
414 | } | |
415 | ||
5c9a8750 DV |
416 | void kcov_task_exit(struct task_struct *t) |
417 | { | |
418 | struct kcov *kcov; | |
5ff3b30a | 419 | unsigned long flags; |
5c9a8750 DV |
420 | |
421 | kcov = t->kcov; | |
422 | if (kcov == NULL) | |
423 | return; | |
eec028c9 | 424 | |
5ff3b30a | 425 | spin_lock_irqsave(&kcov->lock, flags); |
eec028c9 AK |
426 | kcov_debug("t = %px, kcov->t = %px\n", t, kcov->t); |
427 | /* | |
428 | * For KCOV_ENABLE devices we want to make sure that t->kcov->t == t, | |
429 | * which comes down to: | |
430 | * WARN_ON(!kcov->remote && kcov->t != t); | |
431 | * | |
432 | * For KCOV_REMOTE_ENABLE devices, the exiting task is either: | |
3021e692 AK |
433 | * |
434 | * 1. A remote task between kcov_remote_start() and kcov_remote_stop(). | |
eec028c9 AK |
435 | * In this case we should print a warning right away, since a task |
436 | * shouldn't be exiting when it's in a kcov coverage collection | |
437 | * section. Here t points to the task that is collecting remote | |
438 | * coverage, and t->kcov->t points to the thread that created the | |
439 | * kcov device. Which means that to detect this case we need to | |
440 | * check that t != t->kcov->t, and this gives us the following: | |
441 | * WARN_ON(kcov->remote && kcov->t != t); | |
442 | * | |
443 | * 2. The task that created kcov exiting without calling KCOV_DISABLE, | |
3021e692 | 444 | * and then again we make sure that t->kcov->t == t: |
eec028c9 AK |
445 | * WARN_ON(kcov->remote && kcov->t != t); |
446 | * | |
447 | * By combining all three checks into one we get: | |
448 | */ | |
5c9a8750 | 449 | if (WARN_ON(kcov->t != t)) { |
5ff3b30a | 450 | spin_unlock_irqrestore(&kcov->lock, flags); |
5c9a8750 DV |
451 | return; |
452 | } | |
453 | /* Just to not leave dangling references behind. */ | |
eec028c9 | 454 | kcov_disable(t, kcov); |
5ff3b30a | 455 | spin_unlock_irqrestore(&kcov->lock, flags); |
5c9a8750 DV |
456 | kcov_put(kcov); |
457 | } | |
458 | ||
459 | static int kcov_mmap(struct file *filep, struct vm_area_struct *vma) | |
460 | { | |
461 | int res = 0; | |
5c9a8750 DV |
462 | struct kcov *kcov = vma->vm_file->private_data; |
463 | unsigned long size, off; | |
464 | struct page *page; | |
5ff3b30a | 465 | unsigned long flags; |
5c9a8750 | 466 | |
5ff3b30a | 467 | spin_lock_irqsave(&kcov->lock, flags); |
5c9a8750 | 468 | size = kcov->size * sizeof(unsigned long); |
b3d7fe86 | 469 | if (kcov->area == NULL || vma->vm_pgoff != 0 || |
5c9a8750 DV |
470 | vma->vm_end - vma->vm_start != size) { |
471 | res = -EINVAL; | |
472 | goto exit; | |
473 | } | |
b3d7fe86 AN |
474 | spin_unlock_irqrestore(&kcov->lock, flags); |
475 | vma->vm_flags |= VM_DONTEXPAND; | |
476 | for (off = 0; off < size; off += PAGE_SIZE) { | |
477 | page = vmalloc_to_page(kcov->area + off); | |
478 | if (vm_insert_page(vma, vma->vm_start + off, page)) | |
479 | WARN_ONCE(1, "vm_insert_page() failed"); | |
5c9a8750 | 480 | } |
b3d7fe86 | 481 | return 0; |
5c9a8750 | 482 | exit: |
5ff3b30a | 483 | spin_unlock_irqrestore(&kcov->lock, flags); |
5c9a8750 DV |
484 | return res; |
485 | } | |
486 | ||
487 | static int kcov_open(struct inode *inode, struct file *filep) | |
488 | { | |
489 | struct kcov *kcov; | |
490 | ||
491 | kcov = kzalloc(sizeof(*kcov), GFP_KERNEL); | |
492 | if (!kcov) | |
493 | return -ENOMEM; | |
ded97d2c | 494 | kcov->mode = KCOV_MODE_DISABLED; |
eec028c9 | 495 | kcov->sequence = 1; |
39e07cb6 | 496 | refcount_set(&kcov->refcount, 1); |
5c9a8750 DV |
497 | spin_lock_init(&kcov->lock); |
498 | filep->private_data = kcov; | |
499 | return nonseekable_open(inode, filep); | |
500 | } | |
501 | ||
502 | static int kcov_close(struct inode *inode, struct file *filep) | |
503 | { | |
504 | kcov_put(filep->private_data); | |
505 | return 0; | |
506 | } | |
507 | ||
eec028c9 AK |
508 | static int kcov_get_mode(unsigned long arg) |
509 | { | |
510 | if (arg == KCOV_TRACE_PC) | |
511 | return KCOV_MODE_TRACE_PC; | |
512 | else if (arg == KCOV_TRACE_CMP) | |
513 | #ifdef CONFIG_KCOV_ENABLE_COMPARISONS | |
514 | return KCOV_MODE_TRACE_CMP; | |
515 | #else | |
516 | return -ENOTSUPP; | |
517 | #endif | |
518 | else | |
519 | return -EINVAL; | |
520 | } | |
521 | ||
dc55daff MR |
522 | /* |
523 | * Fault in a lazily-faulted vmalloc area before it can be used by | |
524 | * __santizer_cov_trace_pc(), to avoid recursion issues if any code on the | |
525 | * vmalloc fault handling path is instrumented. | |
526 | */ | |
527 | static void kcov_fault_in_area(struct kcov *kcov) | |
528 | { | |
529 | unsigned long stride = PAGE_SIZE / sizeof(unsigned long); | |
530 | unsigned long *area = kcov->area; | |
531 | unsigned long offset; | |
532 | ||
533 | for (offset = 0; offset < kcov->size; offset += stride) | |
534 | READ_ONCE(area[offset]); | |
535 | } | |
536 | ||
eec028c9 AK |
537 | static inline bool kcov_check_handle(u64 handle, bool common_valid, |
538 | bool uncommon_valid, bool zero_valid) | |
539 | { | |
540 | if (handle & ~(KCOV_SUBSYSTEM_MASK | KCOV_INSTANCE_MASK)) | |
541 | return false; | |
542 | switch (handle & KCOV_SUBSYSTEM_MASK) { | |
543 | case KCOV_SUBSYSTEM_COMMON: | |
544 | return (handle & KCOV_INSTANCE_MASK) ? | |
545 | common_valid : zero_valid; | |
546 | case KCOV_SUBSYSTEM_USB: | |
547 | return uncommon_valid; | |
548 | default: | |
549 | return false; | |
550 | } | |
551 | return false; | |
552 | } | |
553 | ||
5c9a8750 DV |
554 | static int kcov_ioctl_locked(struct kcov *kcov, unsigned int cmd, |
555 | unsigned long arg) | |
556 | { | |
557 | struct task_struct *t; | |
17581aa1 | 558 | unsigned long flags, unused; |
eec028c9 AK |
559 | int mode, i; |
560 | struct kcov_remote_arg *remote_arg; | |
561 | struct kcov_remote *remote; | |
5c9a8750 DV |
562 | |
563 | switch (cmd) { | |
5c9a8750 DV |
564 | case KCOV_ENABLE: |
565 | /* | |
566 | * Enable coverage for the current task. | |
567 | * At this point user must have been enabled trace mode, | |
568 | * and mmapped the file. Coverage collection is disabled only | |
569 | * at task exit or voluntary by KCOV_DISABLE. After that it can | |
570 | * be enabled for another task. | |
571 | */ | |
ded97d2c | 572 | if (kcov->mode != KCOV_MODE_INIT || !kcov->area) |
5c9a8750 | 573 | return -EINVAL; |
a77660d2 DV |
574 | t = current; |
575 | if (kcov->t != NULL || t->kcov != NULL) | |
5c9a8750 | 576 | return -EBUSY; |
eec028c9 AK |
577 | mode = kcov_get_mode(arg); |
578 | if (mode < 0) | |
579 | return mode; | |
dc55daff | 580 | kcov_fault_in_area(kcov); |
eec028c9 | 581 | kcov->mode = mode; |
76484b1c | 582 | kcov_start(t, kcov, kcov->size, kcov->area, kcov->mode, |
eec028c9 | 583 | kcov->sequence); |
5c9a8750 | 584 | kcov->t = t; |
eec028c9 | 585 | /* Put either in kcov_task_exit() or in KCOV_DISABLE. */ |
5c9a8750 DV |
586 | kcov_get(kcov); |
587 | return 0; | |
588 | case KCOV_DISABLE: | |
589 | /* Disable coverage for the current task. */ | |
590 | unused = arg; | |
591 | if (unused != 0 || current->kcov != kcov) | |
592 | return -EINVAL; | |
593 | t = current; | |
594 | if (WARN_ON(kcov->t != t)) | |
595 | return -EINVAL; | |
eec028c9 | 596 | kcov_disable(t, kcov); |
5c9a8750 DV |
597 | kcov_put(kcov); |
598 | return 0; | |
eec028c9 | 599 | case KCOV_REMOTE_ENABLE: |
eec028c9 AK |
600 | if (kcov->mode != KCOV_MODE_INIT || !kcov->area) |
601 | return -EINVAL; | |
602 | t = current; | |
603 | if (kcov->t != NULL || t->kcov != NULL) | |
604 | return -EBUSY; | |
605 | remote_arg = (struct kcov_remote_arg *)arg; | |
606 | mode = kcov_get_mode(remote_arg->trace_mode); | |
607 | if (mode < 0) | |
608 | return mode; | |
609 | if (remote_arg->area_size > LONG_MAX / sizeof(unsigned long)) | |
610 | return -EINVAL; | |
611 | kcov->mode = mode; | |
612 | t->kcov = kcov; | |
613 | kcov->t = t; | |
614 | kcov->remote = true; | |
615 | kcov->remote_size = remote_arg->area_size; | |
5ff3b30a | 616 | spin_lock_irqsave(&kcov_remote_lock, flags); |
eec028c9 | 617 | for (i = 0; i < remote_arg->num_handles; i++) { |
eec028c9 AK |
618 | if (!kcov_check_handle(remote_arg->handles[i], |
619 | false, true, false)) { | |
5ff3b30a AK |
620 | spin_unlock_irqrestore(&kcov_remote_lock, |
621 | flags); | |
eec028c9 AK |
622 | kcov_disable(t, kcov); |
623 | return -EINVAL; | |
624 | } | |
625 | remote = kcov_remote_add(kcov, remote_arg->handles[i]); | |
626 | if (IS_ERR(remote)) { | |
5ff3b30a AK |
627 | spin_unlock_irqrestore(&kcov_remote_lock, |
628 | flags); | |
eec028c9 AK |
629 | kcov_disable(t, kcov); |
630 | return PTR_ERR(remote); | |
631 | } | |
632 | } | |
633 | if (remote_arg->common_handle) { | |
eec028c9 AK |
634 | if (!kcov_check_handle(remote_arg->common_handle, |
635 | true, false, false)) { | |
5ff3b30a AK |
636 | spin_unlock_irqrestore(&kcov_remote_lock, |
637 | flags); | |
eec028c9 AK |
638 | kcov_disable(t, kcov); |
639 | return -EINVAL; | |
640 | } | |
641 | remote = kcov_remote_add(kcov, | |
642 | remote_arg->common_handle); | |
643 | if (IS_ERR(remote)) { | |
5ff3b30a AK |
644 | spin_unlock_irqrestore(&kcov_remote_lock, |
645 | flags); | |
eec028c9 AK |
646 | kcov_disable(t, kcov); |
647 | return PTR_ERR(remote); | |
648 | } | |
649 | t->kcov_handle = remote_arg->common_handle; | |
650 | } | |
5ff3b30a | 651 | spin_unlock_irqrestore(&kcov_remote_lock, flags); |
eec028c9 AK |
652 | /* Put either in kcov_task_exit() or in KCOV_DISABLE. */ |
653 | kcov_get(kcov); | |
654 | return 0; | |
5c9a8750 DV |
655 | default: |
656 | return -ENOTTY; | |
657 | } | |
658 | } | |
659 | ||
660 | static long kcov_ioctl(struct file *filep, unsigned int cmd, unsigned long arg) | |
661 | { | |
662 | struct kcov *kcov; | |
663 | int res; | |
eec028c9 AK |
664 | struct kcov_remote_arg *remote_arg = NULL; |
665 | unsigned int remote_num_handles; | |
666 | unsigned long remote_arg_size; | |
17581aa1 | 667 | unsigned long size, flags; |
b3d7fe86 | 668 | void *area; |
eec028c9 | 669 | |
17581aa1 AN |
670 | kcov = filep->private_data; |
671 | switch (cmd) { | |
672 | case KCOV_INIT_TRACE: | |
673 | /* | |
674 | * Enable kcov in trace mode and setup buffer size. | |
675 | * Must happen before anything else. | |
676 | * | |
677 | * First check the size argument - it must be at least 2 | |
b3d7fe86 | 678 | * to hold the current position and one PC. |
17581aa1 AN |
679 | */ |
680 | size = arg; | |
681 | if (size < 2 || size > INT_MAX / sizeof(unsigned long)) | |
682 | return -EINVAL; | |
b3d7fe86 AN |
683 | area = vmalloc_user(size * sizeof(unsigned long)); |
684 | if (area == NULL) | |
685 | return -ENOMEM; | |
17581aa1 AN |
686 | spin_lock_irqsave(&kcov->lock, flags); |
687 | if (kcov->mode != KCOV_MODE_DISABLED) { | |
688 | spin_unlock_irqrestore(&kcov->lock, flags); | |
b3d7fe86 | 689 | vfree(area); |
17581aa1 AN |
690 | return -EBUSY; |
691 | } | |
b3d7fe86 | 692 | kcov->area = area; |
17581aa1 AN |
693 | kcov->size = size; |
694 | kcov->mode = KCOV_MODE_INIT; | |
695 | spin_unlock_irqrestore(&kcov->lock, flags); | |
696 | return 0; | |
697 | case KCOV_REMOTE_ENABLE: | |
eec028c9 AK |
698 | if (get_user(remote_num_handles, (unsigned __user *)(arg + |
699 | offsetof(struct kcov_remote_arg, num_handles)))) | |
700 | return -EFAULT; | |
701 | if (remote_num_handles > KCOV_REMOTE_MAX_HANDLES) | |
702 | return -EINVAL; | |
703 | remote_arg_size = struct_size(remote_arg, handles, | |
704 | remote_num_handles); | |
705 | remote_arg = memdup_user((void __user *)arg, remote_arg_size); | |
706 | if (IS_ERR(remote_arg)) | |
707 | return PTR_ERR(remote_arg); | |
708 | if (remote_arg->num_handles != remote_num_handles) { | |
709 | kfree(remote_arg); | |
710 | return -EINVAL; | |
711 | } | |
712 | arg = (unsigned long)remote_arg; | |
17581aa1 AN |
713 | fallthrough; |
714 | default: | |
715 | /* | |
716 | * All other commands can be normally executed under a spin lock, so we | |
717 | * obtain and release it here in order to simplify kcov_ioctl_locked(). | |
718 | */ | |
719 | spin_lock_irqsave(&kcov->lock, flags); | |
720 | res = kcov_ioctl_locked(kcov, cmd, arg); | |
721 | spin_unlock_irqrestore(&kcov->lock, flags); | |
722 | kfree(remote_arg); | |
723 | return res; | |
eec028c9 | 724 | } |
5c9a8750 DV |
725 | } |
726 | ||
727 | static const struct file_operations kcov_fops = { | |
728 | .open = kcov_open, | |
729 | .unlocked_ioctl = kcov_ioctl, | |
7483e5d4 | 730 | .compat_ioctl = kcov_ioctl, |
5c9a8750 DV |
731 | .mmap = kcov_mmap, |
732 | .release = kcov_close, | |
733 | }; | |
734 | ||
eec028c9 AK |
735 | /* |
736 | * kcov_remote_start() and kcov_remote_stop() can be used to annotate a section | |
5ff3b30a AK |
737 | * of code in a kernel background thread or in a softirq to allow kcov to be |
738 | * used to collect coverage from that part of code. | |
eec028c9 AK |
739 | * |
740 | * The handle argument of kcov_remote_start() identifies a code section that is | |
741 | * used for coverage collection. A userspace process passes this handle to | |
742 | * KCOV_REMOTE_ENABLE ioctl to make the used kcov device start collecting | |
743 | * coverage for the code section identified by this handle. | |
744 | * | |
745 | * The usage of these annotations in the kernel code is different depending on | |
746 | * the type of the kernel thread whose code is being annotated. | |
747 | * | |
748 | * For global kernel threads that are spawned in a limited number of instances | |
5ff3b30a AK |
749 | * (e.g. one USB hub_event() worker thread is spawned per USB HCD) and for |
750 | * softirqs, each instance must be assigned a unique 4-byte instance id. The | |
751 | * instance id is then combined with a 1-byte subsystem id to get a handle via | |
eec028c9 AK |
752 | * kcov_remote_handle(subsystem_id, instance_id). |
753 | * | |
754 | * For local kernel threads that are spawned from system calls handler when a | |
755 | * user interacts with some kernel interface (e.g. vhost workers), a handle is | |
756 | * passed from a userspace process as the common_handle field of the | |
757 | * kcov_remote_arg struct (note, that the user must generate a handle by using | |
758 | * kcov_remote_handle() with KCOV_SUBSYSTEM_COMMON as the subsystem id and an | |
759 | * arbitrary 4-byte non-zero number as the instance id). This common handle | |
760 | * then gets saved into the task_struct of the process that issued the | |
324cfb19 MG |
761 | * KCOV_REMOTE_ENABLE ioctl. When this process issues system calls that spawn |
762 | * kernel threads, the common handle must be retrieved via kcov_common_handle() | |
eec028c9 AK |
763 | * and passed to the spawned threads via custom annotations. Those kernel |
764 | * threads must in turn be annotated with kcov_remote_start(common_handle) and | |
765 | * kcov_remote_stop(). All of the threads that are spawned by the same process | |
766 | * obtain the same handle, hence the name "common". | |
767 | * | |
768 | * See Documentation/dev-tools/kcov.rst for more details. | |
769 | * | |
5ff3b30a | 770 | * Internally, kcov_remote_start() looks up the kcov device associated with the |
eec028c9 AK |
771 | * provided handle, allocates an area for coverage collection, and saves the |
772 | * pointers to kcov and area into the current task_struct to allow coverage to | |
3021e692 | 773 | * be collected via __sanitizer_cov_trace_pc(). |
eec028c9 AK |
774 | * In turns kcov_remote_stop() clears those pointers from task_struct to stop |
775 | * collecting coverage and copies all collected coverage into the kcov area. | |
776 | */ | |
5fe7042d AK |
777 | |
778 | static inline bool kcov_mode_enabled(unsigned int mode) | |
779 | { | |
780 | return (mode & ~KCOV_IN_CTXSW) != KCOV_MODE_DISABLED; | |
781 | } | |
782 | ||
fed79d05 | 783 | static void kcov_remote_softirq_start(struct task_struct *t) |
5ff3b30a AK |
784 | { |
785 | struct kcov_percpu_data *data = this_cpu_ptr(&kcov_percpu_data); | |
786 | unsigned int mode; | |
787 | ||
788 | mode = READ_ONCE(t->kcov_mode); | |
789 | barrier(); | |
790 | if (kcov_mode_enabled(mode)) { | |
791 | data->saved_mode = mode; | |
792 | data->saved_size = t->kcov_size; | |
793 | data->saved_area = t->kcov_area; | |
794 | data->saved_sequence = t->kcov_sequence; | |
795 | data->saved_kcov = t->kcov; | |
796 | kcov_stop(t); | |
797 | } | |
798 | } | |
799 | ||
fed79d05 | 800 | static void kcov_remote_softirq_stop(struct task_struct *t) |
5ff3b30a AK |
801 | { |
802 | struct kcov_percpu_data *data = this_cpu_ptr(&kcov_percpu_data); | |
803 | ||
804 | if (data->saved_kcov) { | |
805 | kcov_start(t, data->saved_kcov, data->saved_size, | |
806 | data->saved_area, data->saved_mode, | |
807 | data->saved_sequence); | |
808 | data->saved_mode = 0; | |
809 | data->saved_size = 0; | |
810 | data->saved_area = NULL; | |
811 | data->saved_sequence = 0; | |
812 | data->saved_kcov = NULL; | |
813 | } | |
814 | } | |
815 | ||
eec028c9 AK |
816 | void kcov_remote_start(u64 handle) |
817 | { | |
5fe7042d | 818 | struct task_struct *t = current; |
eec028c9 | 819 | struct kcov_remote *remote; |
67b3d3cc | 820 | struct kcov *kcov; |
5fe7042d | 821 | unsigned int mode; |
eec028c9 | 822 | void *area; |
eec028c9 | 823 | unsigned int size; |
eec028c9 | 824 | int sequence; |
5ff3b30a | 825 | unsigned long flags; |
eec028c9 AK |
826 | |
827 | if (WARN_ON(!kcov_check_handle(handle, true, true, true))) | |
828 | return; | |
5ff3b30a | 829 | if (!in_task() && !in_serving_softirq()) |
eec028c9 | 830 | return; |
5fe7042d | 831 | |
d5d2c51f | 832 | local_lock_irqsave(&kcov_percpu_data.lock, flags); |
5ff3b30a | 833 | |
eec028c9 | 834 | /* |
5ff3b30a AK |
835 | * Check that kcov_remote_start() is not called twice in background |
836 | * threads nor called by user tasks (with enabled kcov). | |
eec028c9 | 837 | */ |
5fe7042d | 838 | mode = READ_ONCE(t->kcov_mode); |
5ff3b30a | 839 | if (WARN_ON(in_task() && kcov_mode_enabled(mode))) { |
d5d2c51f | 840 | local_unlock_irqrestore(&kcov_percpu_data.lock, flags); |
eec028c9 | 841 | return; |
5ff3b30a AK |
842 | } |
843 | /* | |
844 | * Check that kcov_remote_start() is not called twice in softirqs. | |
845 | * Note, that kcov_remote_start() can be called from a softirq that | |
846 | * happened while collecting coverage from a background thread. | |
847 | */ | |
848 | if (WARN_ON(in_serving_softirq() && t->kcov_softirq)) { | |
d5d2c51f | 849 | local_unlock_irqrestore(&kcov_percpu_data.lock, flags); |
5ff3b30a AK |
850 | return; |
851 | } | |
eec028c9 AK |
852 | |
853 | spin_lock(&kcov_remote_lock); | |
854 | remote = kcov_remote_find(handle); | |
855 | if (!remote) { | |
d5d2c51f SAS |
856 | spin_unlock(&kcov_remote_lock); |
857 | local_unlock_irqrestore(&kcov_percpu_data.lock, flags); | |
eec028c9 AK |
858 | return; |
859 | } | |
5ff3b30a AK |
860 | kcov_debug("handle = %llx, context: %s\n", handle, |
861 | in_task() ? "task" : "softirq"); | |
67b3d3cc | 862 | kcov = remote->kcov; |
eec028c9 | 863 | /* Put in kcov_remote_stop(). */ |
67b3d3cc | 864 | kcov_get(kcov); |
eec028c9 AK |
865 | /* |
866 | * Read kcov fields before unlock to prevent races with | |
867 | * KCOV_DISABLE / kcov_remote_reset(). | |
868 | */ | |
67b3d3cc AK |
869 | mode = kcov->mode; |
870 | sequence = kcov->sequence; | |
5ff3b30a AK |
871 | if (in_task()) { |
872 | size = kcov->remote_size; | |
873 | area = kcov_remote_area_get(size); | |
874 | } else { | |
875 | size = CONFIG_KCOV_IRQ_AREA_SIZE; | |
876 | area = this_cpu_ptr(&kcov_percpu_data)->irq_area; | |
877 | } | |
22036abe | 878 | spin_unlock(&kcov_remote_lock); |
eec028c9 | 879 | |
5ff3b30a | 880 | /* Can only happen when in_task(). */ |
eec028c9 | 881 | if (!area) { |
d5d2c51f | 882 | local_unlock_irqrestore(&kcov_percpu_data.lock, flags); |
eec028c9 AK |
883 | area = vmalloc(size * sizeof(unsigned long)); |
884 | if (!area) { | |
67b3d3cc | 885 | kcov_put(kcov); |
eec028c9 AK |
886 | return; |
887 | } | |
d5d2c51f | 888 | local_lock_irqsave(&kcov_percpu_data.lock, flags); |
eec028c9 | 889 | } |
5ff3b30a | 890 | |
eec028c9 AK |
891 | /* Reset coverage size. */ |
892 | *(u64 *)area = 0; | |
893 | ||
5ff3b30a AK |
894 | if (in_serving_softirq()) { |
895 | kcov_remote_softirq_start(t); | |
896 | t->kcov_softirq = 1; | |
897 | } | |
76484b1c | 898 | kcov_start(t, kcov, size, area, mode, sequence); |
eec028c9 | 899 | |
d5d2c51f | 900 | local_unlock_irqrestore(&kcov_percpu_data.lock, flags); |
5ff3b30a | 901 | |
eec028c9 AK |
902 | } |
903 | EXPORT_SYMBOL(kcov_remote_start); | |
904 | ||
905 | static void kcov_move_area(enum kcov_mode mode, void *dst_area, | |
906 | unsigned int dst_area_size, void *src_area) | |
907 | { | |
908 | u64 word_size = sizeof(unsigned long); | |
909 | u64 count_size, entry_size_log; | |
910 | u64 dst_len, src_len; | |
911 | void *dst_entries, *src_entries; | |
912 | u64 dst_occupied, dst_free, bytes_to_move, entries_moved; | |
913 | ||
914 | kcov_debug("%px %u <= %px %lu\n", | |
915 | dst_area, dst_area_size, src_area, *(unsigned long *)src_area); | |
916 | ||
917 | switch (mode) { | |
918 | case KCOV_MODE_TRACE_PC: | |
919 | dst_len = READ_ONCE(*(unsigned long *)dst_area); | |
920 | src_len = *(unsigned long *)src_area; | |
921 | count_size = sizeof(unsigned long); | |
922 | entry_size_log = __ilog2_u64(sizeof(unsigned long)); | |
923 | break; | |
924 | case KCOV_MODE_TRACE_CMP: | |
925 | dst_len = READ_ONCE(*(u64 *)dst_area); | |
926 | src_len = *(u64 *)src_area; | |
927 | count_size = sizeof(u64); | |
928 | BUILD_BUG_ON(!is_power_of_2(KCOV_WORDS_PER_CMP)); | |
929 | entry_size_log = __ilog2_u64(sizeof(u64) * KCOV_WORDS_PER_CMP); | |
930 | break; | |
931 | default: | |
932 | WARN_ON(1); | |
933 | return; | |
934 | } | |
935 | ||
936 | /* As arm can't divide u64 integers use log of entry size. */ | |
937 | if (dst_len > ((dst_area_size * word_size - count_size) >> | |
938 | entry_size_log)) | |
939 | return; | |
940 | dst_occupied = count_size + (dst_len << entry_size_log); | |
941 | dst_free = dst_area_size * word_size - dst_occupied; | |
942 | bytes_to_move = min(dst_free, src_len << entry_size_log); | |
943 | dst_entries = dst_area + dst_occupied; | |
944 | src_entries = src_area + count_size; | |
945 | memcpy(dst_entries, src_entries, bytes_to_move); | |
946 | entries_moved = bytes_to_move >> entry_size_log; | |
947 | ||
948 | switch (mode) { | |
949 | case KCOV_MODE_TRACE_PC: | |
950 | WRITE_ONCE(*(unsigned long *)dst_area, dst_len + entries_moved); | |
951 | break; | |
952 | case KCOV_MODE_TRACE_CMP: | |
953 | WRITE_ONCE(*(u64 *)dst_area, dst_len + entries_moved); | |
954 | break; | |
955 | default: | |
956 | break; | |
957 | } | |
958 | } | |
959 | ||
960 | /* See the comment before kcov_remote_start() for usage details. */ | |
961 | void kcov_remote_stop(void) | |
962 | { | |
963 | struct task_struct *t = current; | |
5fe7042d AK |
964 | struct kcov *kcov; |
965 | unsigned int mode; | |
966 | void *area; | |
967 | unsigned int size; | |
968 | int sequence; | |
5ff3b30a AK |
969 | unsigned long flags; |
970 | ||
971 | if (!in_task() && !in_serving_softirq()) | |
972 | return; | |
973 | ||
d5d2c51f | 974 | local_lock_irqsave(&kcov_percpu_data.lock, flags); |
eec028c9 | 975 | |
5fe7042d AK |
976 | mode = READ_ONCE(t->kcov_mode); |
977 | barrier(); | |
5ff3b30a | 978 | if (!kcov_mode_enabled(mode)) { |
d5d2c51f | 979 | local_unlock_irqrestore(&kcov_percpu_data.lock, flags); |
eec028c9 | 980 | return; |
5ff3b30a | 981 | } |
3021e692 AK |
982 | /* |
983 | * When in softirq, check if the corresponding kcov_remote_start() | |
984 | * actually found the remote handle and started collecting coverage. | |
985 | */ | |
986 | if (in_serving_softirq() && !t->kcov_softirq) { | |
d5d2c51f | 987 | local_unlock_irqrestore(&kcov_percpu_data.lock, flags); |
3021e692 AK |
988 | return; |
989 | } | |
990 | /* Make sure that kcov_softirq is only set when in softirq. */ | |
5ff3b30a | 991 | if (WARN_ON(!in_serving_softirq() && t->kcov_softirq)) { |
d5d2c51f | 992 | local_unlock_irqrestore(&kcov_percpu_data.lock, flags); |
5ff3b30a AK |
993 | return; |
994 | } | |
995 | ||
3021e692 AK |
996 | kcov = t->kcov; |
997 | area = t->kcov_area; | |
998 | size = t->kcov_size; | |
999 | sequence = t->kcov_sequence; | |
1000 | ||
eec028c9 | 1001 | kcov_stop(t); |
5ff3b30a AK |
1002 | if (in_serving_softirq()) { |
1003 | t->kcov_softirq = 0; | |
1004 | kcov_remote_softirq_stop(t); | |
1005 | } | |
eec028c9 AK |
1006 | |
1007 | spin_lock(&kcov->lock); | |
1008 | /* | |
1009 | * KCOV_DISABLE could have been called between kcov_remote_start() | |
5ff3b30a | 1010 | * and kcov_remote_stop(), hence the sequence check. |
eec028c9 | 1011 | */ |
eec028c9 AK |
1012 | if (sequence == kcov->sequence && kcov->remote) |
1013 | kcov_move_area(kcov->mode, kcov->area, kcov->size, area); | |
1014 | spin_unlock(&kcov->lock); | |
1015 | ||
5ff3b30a AK |
1016 | if (in_task()) { |
1017 | spin_lock(&kcov_remote_lock); | |
1018 | kcov_remote_area_put(area, size); | |
1019 | spin_unlock(&kcov_remote_lock); | |
1020 | } | |
eec028c9 | 1021 | |
d5d2c51f | 1022 | local_unlock_irqrestore(&kcov_percpu_data.lock, flags); |
5ff3b30a AK |
1023 | |
1024 | /* Get in kcov_remote_start(). */ | |
eec028c9 AK |
1025 | kcov_put(kcov); |
1026 | } | |
1027 | EXPORT_SYMBOL(kcov_remote_stop); | |
1028 | ||
1029 | /* See the comment before kcov_remote_start() for usage details. */ | |
1030 | u64 kcov_common_handle(void) | |
1031 | { | |
b08e84da AN |
1032 | if (!in_task()) |
1033 | return 0; | |
eec028c9 AK |
1034 | return current->kcov_handle; |
1035 | } | |
1036 | EXPORT_SYMBOL(kcov_common_handle); | |
1037 | ||
5c9a8750 DV |
1038 | static int __init kcov_init(void) |
1039 | { | |
5ff3b30a AK |
1040 | int cpu; |
1041 | ||
1042 | for_each_possible_cpu(cpu) { | |
741ddd45 SAS |
1043 | void *area = vmalloc_node(CONFIG_KCOV_IRQ_AREA_SIZE * |
1044 | sizeof(unsigned long), cpu_to_node(cpu)); | |
5ff3b30a AK |
1045 | if (!area) |
1046 | return -ENOMEM; | |
1047 | per_cpu_ptr(&kcov_percpu_data, cpu)->irq_area = area; | |
1048 | } | |
1049 | ||
df4565f9 NS |
1050 | /* |
1051 | * The kcov debugfs file won't ever get removed and thus, | |
1052 | * there is no need to protect it against removal races. The | |
1053 | * use of debugfs_create_file_unsafe() is actually safe here. | |
1054 | */ | |
ec9672d5 GKH |
1055 | debugfs_create_file_unsafe("kcov", 0600, NULL, NULL, &kcov_fops); |
1056 | ||
5c9a8750 DV |
1057 | return 0; |
1058 | } | |
1059 | ||
1060 | device_initcall(kcov_init); |