Commit | Line | Data |
---|---|---|
62a038d3 P |
1 | /* |
2 | * This program is free software; you can redistribute it and/or modify | |
3 | * it under the terms of the GNU General Public License as published by | |
4 | * the Free Software Foundation; either version 2 of the License, or | |
5 | * (at your option) any later version. | |
6 | * | |
7 | * This program is distributed in the hope that it will be useful, | |
8 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
10 | * GNU General Public License for more details. | |
11 | * | |
12 | * You should have received a copy of the GNU General Public License | |
13 | * along with this program; if not, write to the Free Software | |
14 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
15 | * | |
16 | * Copyright (C) 2007 Alan Stern | |
17 | * Copyright (C) IBM Corporation, 2009 | |
24f1e32c | 18 | * Copyright (C) 2009, Frederic Weisbecker <fweisbec@gmail.com> |
ba1c813a FW |
19 | * |
20 | * Thanks to Ingo Molnar for his many suggestions. | |
ba6909b7 P |
21 | * |
22 | * Authors: Alan Stern <stern@rowland.harvard.edu> | |
23 | * K.Prasad <prasad@linux.vnet.ibm.com> | |
24 | * Frederic Weisbecker <fweisbec@gmail.com> | |
62a038d3 P |
25 | */ |
26 | ||
27 | /* | |
28 | * HW_breakpoint: a unified kernel/user-space hardware breakpoint facility, | |
29 | * using the CPU's debug registers. | |
30 | * This file contains the arch-independent routines. | |
31 | */ | |
32 | ||
33 | #include <linux/irqflags.h> | |
34 | #include <linux/kallsyms.h> | |
35 | #include <linux/notifier.h> | |
36 | #include <linux/kprobes.h> | |
37 | #include <linux/kdebug.h> | |
38 | #include <linux/kernel.h> | |
39 | #include <linux/module.h> | |
40 | #include <linux/percpu.h> | |
41 | #include <linux/sched.h> | |
42 | #include <linux/init.h> | |
feef47d0 | 43 | #include <linux/slab.h> |
45a73372 | 44 | #include <linux/list.h> |
88f7a890 | 45 | #include <linux/cpu.h> |
62a038d3 P |
46 | #include <linux/smp.h> |
47 | ||
24f1e32c FW |
48 | #include <linux/hw_breakpoint.h> |
49 | ||
0102752e | 50 | |
ba1c813a FW |
51 | /* |
52 | * Constraints data | |
53 | */ | |
62a038d3 | 54 | |
ba1c813a | 55 | /* Number of pinned cpu breakpoints in a cpu */ |
0102752e | 56 | static DEFINE_PER_CPU(unsigned int, nr_cpu_bp_pinned[TYPE_MAX]); |
ba1c813a FW |
57 | |
58 | /* Number of pinned task breakpoints in a cpu */ | |
777d0411 | 59 | static DEFINE_PER_CPU(unsigned int *, nr_task_bp_pinned[TYPE_MAX]); |
ba1c813a FW |
60 | |
61 | /* Number of non-pinned cpu/task breakpoints in a cpu */ | |
0102752e | 62 | static DEFINE_PER_CPU(unsigned int, nr_bp_flexible[TYPE_MAX]); |
ba1c813a | 63 | |
feef47d0 FW |
64 | static int nr_slots[TYPE_MAX]; |
65 | ||
45a73372 FW |
66 | /* Keep track of the breakpoints attached to tasks */ |
67 | static LIST_HEAD(bp_task_head); | |
68 | ||
feef47d0 FW |
69 | static int constraints_initialized; |
70 | ||
ba1c813a FW |
71 | /* Gather the number of total pinned and un-pinned bp in a cpuset */ |
72 | struct bp_busy_slots { | |
73 | unsigned int pinned; | |
74 | unsigned int flexible; | |
75 | }; | |
76 | ||
77 | /* Serialize accesses to the above constraints */ | |
78 | static DEFINE_MUTEX(nr_bp_mutex); | |
79 | ||
f93a2054 FW |
80 | __weak int hw_breakpoint_weight(struct perf_event *bp) |
81 | { | |
82 | return 1; | |
83 | } | |
84 | ||
0102752e FW |
85 | static inline enum bp_type_idx find_slot_idx(struct perf_event *bp) |
86 | { | |
87 | if (bp->attr.bp_type & HW_BREAKPOINT_RW) | |
88 | return TYPE_DATA; | |
89 | ||
90 | return TYPE_INST; | |
91 | } | |
92 | ||
ba1c813a FW |
93 | /* |
94 | * Report the maximum number of pinned breakpoints a task | |
95 | * have in this cpu | |
96 | */ | |
0102752e | 97 | static unsigned int max_task_bp_pinned(int cpu, enum bp_type_idx type) |
62a038d3 | 98 | { |
ba1c813a | 99 | int i; |
0102752e | 100 | unsigned int *tsk_pinned = per_cpu(nr_task_bp_pinned[type], cpu); |
62a038d3 | 101 | |
feef47d0 | 102 | for (i = nr_slots[type] - 1; i >= 0; i--) { |
ba1c813a FW |
103 | if (tsk_pinned[i] > 0) |
104 | return i + 1; | |
62a038d3 P |
105 | } |
106 | ||
24f1e32c | 107 | return 0; |
62a038d3 P |
108 | } |
109 | ||
45a73372 FW |
110 | /* |
111 | * Count the number of breakpoints of the same type and same task. | |
112 | * The given event must be not on the list. | |
113 | */ | |
0d855354 | 114 | static int task_bp_pinned(int cpu, struct perf_event *bp, enum bp_type_idx type) |
56053170 | 115 | { |
d580ff86 | 116 | struct task_struct *tsk = bp->hw.bp_target; |
45a73372 | 117 | struct perf_event *iter; |
56053170 FW |
118 | int count = 0; |
119 | ||
45a73372 | 120 | list_for_each_entry(iter, &bp_task_head, hw.bp_list) { |
0d855354 MN |
121 | if (iter->hw.bp_target == tsk && |
122 | find_slot_idx(iter) == type && | |
123 | cpu == iter->cpu) | |
45a73372 | 124 | count += hw_breakpoint_weight(iter); |
56053170 FW |
125 | } |
126 | ||
56053170 FW |
127 | return count; |
128 | } | |
129 | ||
ba1c813a FW |
130 | /* |
131 | * Report the number of pinned/un-pinned breakpoints we have in | |
132 | * a given cpu (cpu > -1) or in all of them (cpu = -1). | |
133 | */ | |
56053170 | 134 | static void |
0102752e FW |
135 | fetch_bp_busy_slots(struct bp_busy_slots *slots, struct perf_event *bp, |
136 | enum bp_type_idx type) | |
ba1c813a | 137 | { |
56053170 | 138 | int cpu = bp->cpu; |
d580ff86 | 139 | struct task_struct *tsk = bp->hw.bp_target; |
56053170 | 140 | |
ba1c813a | 141 | if (cpu >= 0) { |
0102752e | 142 | slots->pinned = per_cpu(nr_cpu_bp_pinned[type], cpu); |
56053170 | 143 | if (!tsk) |
0102752e | 144 | slots->pinned += max_task_bp_pinned(cpu, type); |
56053170 | 145 | else |
0d855354 | 146 | slots->pinned += task_bp_pinned(cpu, bp, type); |
0102752e | 147 | slots->flexible = per_cpu(nr_bp_flexible[type], cpu); |
ba1c813a FW |
148 | |
149 | return; | |
150 | } | |
151 | ||
152 | for_each_online_cpu(cpu) { | |
153 | unsigned int nr; | |
154 | ||
0102752e | 155 | nr = per_cpu(nr_cpu_bp_pinned[type], cpu); |
56053170 | 156 | if (!tsk) |
0102752e | 157 | nr += max_task_bp_pinned(cpu, type); |
56053170 | 158 | else |
0d855354 | 159 | nr += task_bp_pinned(cpu, bp, type); |
ba1c813a FW |
160 | |
161 | if (nr > slots->pinned) | |
162 | slots->pinned = nr; | |
163 | ||
0102752e | 164 | nr = per_cpu(nr_bp_flexible[type], cpu); |
ba1c813a FW |
165 | |
166 | if (nr > slots->flexible) | |
167 | slots->flexible = nr; | |
168 | } | |
169 | } | |
170 | ||
f93a2054 FW |
171 | /* |
172 | * For now, continue to consider flexible as pinned, until we can | |
173 | * ensure no flexible event can ever be scheduled before a pinned event | |
174 | * in a same cpu. | |
175 | */ | |
176 | static void | |
177 | fetch_this_slot(struct bp_busy_slots *slots, int weight) | |
178 | { | |
179 | slots->pinned += weight; | |
180 | } | |
181 | ||
ba1c813a FW |
182 | /* |
183 | * Add a pinned breakpoint for the given task in our constraint table | |
184 | */ | |
45a73372 | 185 | static void toggle_bp_task_slot(struct perf_event *bp, int cpu, bool enable, |
f93a2054 | 186 | enum bp_type_idx type, int weight) |
ba1c813a | 187 | { |
11e66357 | 188 | unsigned int *tsk_pinned; |
f93a2054 FW |
189 | int old_count = 0; |
190 | int old_idx = 0; | |
191 | int idx = 0; | |
ba1c813a | 192 | |
0d855354 | 193 | old_count = task_bp_pinned(cpu, bp, type); |
f93a2054 FW |
194 | old_idx = old_count - 1; |
195 | idx = old_idx + weight; | |
ba1c813a | 196 | |
45a73372 | 197 | /* tsk_pinned[n] is the number of tasks having n breakpoints */ |
0102752e | 198 | tsk_pinned = per_cpu(nr_task_bp_pinned[type], cpu); |
ba1c813a | 199 | if (enable) { |
f93a2054 FW |
200 | tsk_pinned[idx]++; |
201 | if (old_count > 0) | |
202 | tsk_pinned[old_idx]--; | |
ba1c813a | 203 | } else { |
f93a2054 FW |
204 | tsk_pinned[idx]--; |
205 | if (old_count > 0) | |
206 | tsk_pinned[old_idx]++; | |
ba1c813a FW |
207 | } |
208 | } | |
209 | ||
210 | /* | |
211 | * Add/remove the given breakpoint in our constraint table | |
212 | */ | |
0102752e | 213 | static void |
f93a2054 FW |
214 | toggle_bp_slot(struct perf_event *bp, bool enable, enum bp_type_idx type, |
215 | int weight) | |
ba1c813a FW |
216 | { |
217 | int cpu = bp->cpu; | |
d580ff86 | 218 | struct task_struct *tsk = bp->hw.bp_target; |
ba1c813a | 219 | |
45a73372 FW |
220 | /* Pinned counter cpu profiling */ |
221 | if (!tsk) { | |
222 | ||
223 | if (enable) | |
224 | per_cpu(nr_cpu_bp_pinned[type], bp->cpu) += weight; | |
225 | else | |
226 | per_cpu(nr_cpu_bp_pinned[type], bp->cpu) -= weight; | |
227 | return; | |
228 | } | |
229 | ||
ba1c813a | 230 | /* Pinned counter task profiling */ |
ba1c813a | 231 | |
45a73372 FW |
232 | if (!enable) |
233 | list_del(&bp->hw.bp_list); | |
234 | ||
235 | if (cpu >= 0) { | |
236 | toggle_bp_task_slot(bp, cpu, enable, type, weight); | |
237 | } else { | |
ba1c813a | 238 | for_each_online_cpu(cpu) |
45a73372 | 239 | toggle_bp_task_slot(bp, cpu, enable, type, weight); |
ba1c813a FW |
240 | } |
241 | ||
ba1c813a | 242 | if (enable) |
45a73372 | 243 | list_add_tail(&bp->hw.bp_list, &bp_task_head); |
ba1c813a FW |
244 | } |
245 | ||
f7136c51 P |
246 | /* |
247 | * Function to perform processor-specific cleanup during unregistration | |
248 | */ | |
249 | __weak void arch_unregister_hw_breakpoint(struct perf_event *bp) | |
250 | { | |
251 | /* | |
252 | * A weak stub function here for those archs that don't define | |
253 | * it inside arch/.../kernel/hw_breakpoint.c | |
254 | */ | |
255 | } | |
256 | ||
ba1c813a FW |
257 | /* |
258 | * Contraints to check before allowing this new breakpoint counter: | |
259 | * | |
260 | * == Non-pinned counter == (Considered as pinned for now) | |
261 | * | |
262 | * - If attached to a single cpu, check: | |
263 | * | |
264 | * (per_cpu(nr_bp_flexible, cpu) || (per_cpu(nr_cpu_bp_pinned, cpu) | |
6ab88863 | 265 | * + max(per_cpu(nr_task_bp_pinned, cpu)))) < HBP_NUM |
ba1c813a FW |
266 | * |
267 | * -> If there are already non-pinned counters in this cpu, it means | |
268 | * there is already a free slot for them. | |
269 | * Otherwise, we check that the maximum number of per task | |
270 | * breakpoints (for this cpu) plus the number of per cpu breakpoint | |
271 | * (for this cpu) doesn't cover every registers. | |
272 | * | |
273 | * - If attached to every cpus, check: | |
274 | * | |
275 | * (per_cpu(nr_bp_flexible, *) || (max(per_cpu(nr_cpu_bp_pinned, *)) | |
6ab88863 | 276 | * + max(per_cpu(nr_task_bp_pinned, *)))) < HBP_NUM |
ba1c813a FW |
277 | * |
278 | * -> This is roughly the same, except we check the number of per cpu | |
279 | * bp for every cpu and we keep the max one. Same for the per tasks | |
280 | * breakpoints. | |
281 | * | |
282 | * | |
283 | * == Pinned counter == | |
284 | * | |
285 | * - If attached to a single cpu, check: | |
286 | * | |
287 | * ((per_cpu(nr_bp_flexible, cpu) > 1) + per_cpu(nr_cpu_bp_pinned, cpu) | |
6ab88863 | 288 | * + max(per_cpu(nr_task_bp_pinned, cpu))) < HBP_NUM |
ba1c813a FW |
289 | * |
290 | * -> Same checks as before. But now the nr_bp_flexible, if any, must keep | |
291 | * one register at least (or they will never be fed). | |
292 | * | |
293 | * - If attached to every cpus, check: | |
294 | * | |
295 | * ((per_cpu(nr_bp_flexible, *) > 1) + max(per_cpu(nr_cpu_bp_pinned, *)) | |
6ab88863 | 296 | * + max(per_cpu(nr_task_bp_pinned, *))) < HBP_NUM |
ba1c813a | 297 | */ |
5352ae63 | 298 | static int __reserve_bp_slot(struct perf_event *bp) |
ba1c813a FW |
299 | { |
300 | struct bp_busy_slots slots = {0}; | |
0102752e | 301 | enum bp_type_idx type; |
f93a2054 | 302 | int weight; |
ba1c813a | 303 | |
feef47d0 FW |
304 | /* We couldn't initialize breakpoint constraints on boot */ |
305 | if (!constraints_initialized) | |
306 | return -ENOMEM; | |
307 | ||
0102752e FW |
308 | /* Basic checks */ |
309 | if (bp->attr.bp_type == HW_BREAKPOINT_EMPTY || | |
310 | bp->attr.bp_type == HW_BREAKPOINT_INVALID) | |
311 | return -EINVAL; | |
312 | ||
313 | type = find_slot_idx(bp); | |
f93a2054 FW |
314 | weight = hw_breakpoint_weight(bp); |
315 | ||
0102752e | 316 | fetch_bp_busy_slots(&slots, bp, type); |
45a73372 FW |
317 | /* |
318 | * Simulate the addition of this breakpoint to the constraints | |
319 | * and see the result. | |
320 | */ | |
f93a2054 | 321 | fetch_this_slot(&slots, weight); |
ba1c813a FW |
322 | |
323 | /* Flexible counters need to keep at least one slot */ | |
feef47d0 | 324 | if (slots.pinned + (!!slots.flexible) > nr_slots[type]) |
5352ae63 | 325 | return -ENOSPC; |
ba1c813a | 326 | |
f93a2054 | 327 | toggle_bp_slot(bp, true, type, weight); |
ba1c813a | 328 | |
5352ae63 JW |
329 | return 0; |
330 | } | |
331 | ||
332 | int reserve_bp_slot(struct perf_event *bp) | |
333 | { | |
334 | int ret; | |
335 | ||
336 | mutex_lock(&nr_bp_mutex); | |
337 | ||
338 | ret = __reserve_bp_slot(bp); | |
339 | ||
ba1c813a FW |
340 | mutex_unlock(&nr_bp_mutex); |
341 | ||
342 | return ret; | |
343 | } | |
344 | ||
5352ae63 JW |
345 | static void __release_bp_slot(struct perf_event *bp) |
346 | { | |
0102752e | 347 | enum bp_type_idx type; |
f93a2054 | 348 | int weight; |
0102752e FW |
349 | |
350 | type = find_slot_idx(bp); | |
f93a2054 FW |
351 | weight = hw_breakpoint_weight(bp); |
352 | toggle_bp_slot(bp, false, type, weight); | |
5352ae63 JW |
353 | } |
354 | ||
24f1e32c | 355 | void release_bp_slot(struct perf_event *bp) |
62a038d3 | 356 | { |
ba1c813a FW |
357 | mutex_lock(&nr_bp_mutex); |
358 | ||
f7136c51 | 359 | arch_unregister_hw_breakpoint(bp); |
5352ae63 | 360 | __release_bp_slot(bp); |
ba1c813a FW |
361 | |
362 | mutex_unlock(&nr_bp_mutex); | |
62a038d3 P |
363 | } |
364 | ||
5352ae63 JW |
365 | /* |
366 | * Allow the kernel debugger to reserve breakpoint slots without | |
367 | * taking a lock using the dbg_* variant of for the reserve and | |
368 | * release breakpoint slots. | |
369 | */ | |
370 | int dbg_reserve_bp_slot(struct perf_event *bp) | |
371 | { | |
372 | if (mutex_is_locked(&nr_bp_mutex)) | |
373 | return -1; | |
374 | ||
375 | return __reserve_bp_slot(bp); | |
376 | } | |
377 | ||
378 | int dbg_release_bp_slot(struct perf_event *bp) | |
379 | { | |
380 | if (mutex_is_locked(&nr_bp_mutex)) | |
381 | return -1; | |
382 | ||
383 | __release_bp_slot(bp); | |
384 | ||
385 | return 0; | |
386 | } | |
ba1c813a | 387 | |
b2812d03 FW |
388 | static int validate_hw_breakpoint(struct perf_event *bp) |
389 | { | |
390 | int ret; | |
391 | ||
392 | ret = arch_validate_hwbkpt_settings(bp); | |
393 | if (ret) | |
394 | return ret; | |
395 | ||
396 | if (arch_check_bp_in_kernelspace(bp)) { | |
397 | if (bp->attr.exclude_kernel) | |
398 | return -EINVAL; | |
399 | /* | |
400 | * Don't let unprivileged users set a breakpoint in the trap | |
401 | * path to avoid trap recursion attacks. | |
402 | */ | |
403 | if (!capable(CAP_SYS_ADMIN)) | |
404 | return -EPERM; | |
405 | } | |
406 | ||
407 | return 0; | |
408 | } | |
409 | ||
b326e956 | 410 | int register_perf_hw_breakpoint(struct perf_event *bp) |
62a038d3 | 411 | { |
24f1e32c | 412 | int ret; |
62a038d3 | 413 | |
24f1e32c FW |
414 | ret = reserve_bp_slot(bp); |
415 | if (ret) | |
416 | return ret; | |
62a038d3 | 417 | |
b2812d03 | 418 | ret = validate_hw_breakpoint(bp); |
62a038d3 | 419 | |
b23ff0e9 MS |
420 | /* if arch_validate_hwbkpt_settings() fails then release bp slot */ |
421 | if (ret) | |
422 | release_bp_slot(bp); | |
423 | ||
24f1e32c FW |
424 | return ret; |
425 | } | |
62a038d3 | 426 | |
62a038d3 P |
427 | /** |
428 | * register_user_hw_breakpoint - register a hardware breakpoint for user space | |
5fa10b28 | 429 | * @attr: breakpoint attributes |
24f1e32c | 430 | * @triggered: callback to trigger when we hit the breakpoint |
62a038d3 | 431 | * @tsk: pointer to 'task_struct' of the process to which the address belongs |
62a038d3 | 432 | */ |
24f1e32c | 433 | struct perf_event * |
5fa10b28 | 434 | register_user_hw_breakpoint(struct perf_event_attr *attr, |
b326e956 | 435 | perf_overflow_handler_t triggered, |
4dc0da86 | 436 | void *context, |
5fa10b28 | 437 | struct task_struct *tsk) |
62a038d3 | 438 | { |
4dc0da86 AK |
439 | return perf_event_create_kernel_counter(attr, -1, tsk, triggered, |
440 | context); | |
62a038d3 P |
441 | } |
442 | EXPORT_SYMBOL_GPL(register_user_hw_breakpoint); | |
443 | ||
444 | /** | |
445 | * modify_user_hw_breakpoint - modify a user-space hardware breakpoint | |
24f1e32c | 446 | * @bp: the breakpoint structure to modify |
5fa10b28 | 447 | * @attr: new breakpoint attributes |
24f1e32c | 448 | * @triggered: callback to trigger when we hit the breakpoint |
62a038d3 | 449 | * @tsk: pointer to 'task_struct' of the process to which the address belongs |
62a038d3 | 450 | */ |
44234adc | 451 | int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *attr) |
62a038d3 | 452 | { |
44234adc | 453 | u64 old_addr = bp->attr.bp_addr; |
cd757645 | 454 | u64 old_len = bp->attr.bp_len; |
44234adc | 455 | int old_type = bp->attr.bp_type; |
44234adc FW |
456 | int err = 0; |
457 | ||
500ad2d8 P |
458 | /* |
459 | * modify_user_hw_breakpoint can be invoked with IRQs disabled and hence it | |
460 | * will not be possible to raise IPIs that invoke __perf_event_disable. | |
461 | * So call the function directly after making sure we are targeting the | |
462 | * current task. | |
463 | */ | |
464 | if (irqs_disabled() && bp->ctx && bp->ctx->task == current) | |
465 | __perf_event_disable(bp); | |
466 | else | |
467 | perf_event_disable(bp); | |
44234adc FW |
468 | |
469 | bp->attr.bp_addr = attr->bp_addr; | |
470 | bp->attr.bp_type = attr->bp_type; | |
471 | bp->attr.bp_len = attr->bp_len; | |
472 | ||
473 | if (attr->disabled) | |
474 | goto end; | |
62a038d3 | 475 | |
b2812d03 | 476 | err = validate_hw_breakpoint(bp); |
44234adc FW |
477 | if (!err) |
478 | perf_event_enable(bp); | |
479 | ||
480 | if (err) { | |
481 | bp->attr.bp_addr = old_addr; | |
482 | bp->attr.bp_type = old_type; | |
483 | bp->attr.bp_len = old_len; | |
484 | if (!bp->attr.disabled) | |
485 | perf_event_enable(bp); | |
486 | ||
487 | return err; | |
488 | } | |
489 | ||
490 | end: | |
491 | bp->attr.disabled = attr->disabled; | |
492 | ||
493 | return 0; | |
62a038d3 P |
494 | } |
495 | EXPORT_SYMBOL_GPL(modify_user_hw_breakpoint); | |
496 | ||
497 | /** | |
24f1e32c | 498 | * unregister_hw_breakpoint - unregister a user-space hardware breakpoint |
62a038d3 | 499 | * @bp: the breakpoint structure to unregister |
62a038d3 | 500 | */ |
24f1e32c | 501 | void unregister_hw_breakpoint(struct perf_event *bp) |
62a038d3 | 502 | { |
24f1e32c FW |
503 | if (!bp) |
504 | return; | |
505 | perf_event_release_kernel(bp); | |
506 | } | |
507 | EXPORT_SYMBOL_GPL(unregister_hw_breakpoint); | |
508 | ||
62a038d3 | 509 | /** |
24f1e32c | 510 | * register_wide_hw_breakpoint - register a wide breakpoint in the kernel |
dd1853c3 | 511 | * @attr: breakpoint attributes |
24f1e32c | 512 | * @triggered: callback to trigger when we hit the breakpoint |
62a038d3 | 513 | * |
24f1e32c | 514 | * @return a set of per_cpu pointers to perf events |
62a038d3 | 515 | */ |
44ee6358 | 516 | struct perf_event * __percpu * |
dd1853c3 | 517 | register_wide_hw_breakpoint(struct perf_event_attr *attr, |
4dc0da86 AK |
518 | perf_overflow_handler_t triggered, |
519 | void *context) | |
62a038d3 | 520 | { |
44ee6358 | 521 | struct perf_event * __percpu *cpu_events, **pevent, *bp; |
24f1e32c FW |
522 | long err; |
523 | int cpu; | |
524 | ||
525 | cpu_events = alloc_percpu(typeof(*cpu_events)); | |
526 | if (!cpu_events) | |
44ee6358 | 527 | return (void __percpu __force *)ERR_PTR(-ENOMEM); |
62a038d3 | 528 | |
88f7a890 LZ |
529 | get_online_cpus(); |
530 | for_each_online_cpu(cpu) { | |
24f1e32c | 531 | pevent = per_cpu_ptr(cpu_events, cpu); |
4dc0da86 AK |
532 | bp = perf_event_create_kernel_counter(attr, cpu, NULL, |
533 | triggered, context); | |
62a038d3 | 534 | |
24f1e32c | 535 | *pevent = bp; |
62a038d3 | 536 | |
605bfaee | 537 | if (IS_ERR(bp)) { |
24f1e32c FW |
538 | err = PTR_ERR(bp); |
539 | goto fail; | |
540 | } | |
62a038d3 | 541 | } |
88f7a890 | 542 | put_online_cpus(); |
62a038d3 | 543 | |
24f1e32c FW |
544 | return cpu_events; |
545 | ||
546 | fail: | |
88f7a890 | 547 | for_each_online_cpu(cpu) { |
24f1e32c | 548 | pevent = per_cpu_ptr(cpu_events, cpu); |
605bfaee | 549 | if (IS_ERR(*pevent)) |
24f1e32c FW |
550 | break; |
551 | unregister_hw_breakpoint(*pevent); | |
552 | } | |
88f7a890 LZ |
553 | put_online_cpus(); |
554 | ||
24f1e32c | 555 | free_percpu(cpu_events); |
44ee6358 | 556 | return (void __percpu __force *)ERR_PTR(err); |
62a038d3 | 557 | } |
f60d24d2 | 558 | EXPORT_SYMBOL_GPL(register_wide_hw_breakpoint); |
62a038d3 P |
559 | |
560 | /** | |
24f1e32c FW |
561 | * unregister_wide_hw_breakpoint - unregister a wide breakpoint in the kernel |
562 | * @cpu_events: the per cpu set of events to unregister | |
62a038d3 | 563 | */ |
44ee6358 | 564 | void unregister_wide_hw_breakpoint(struct perf_event * __percpu *cpu_events) |
62a038d3 | 565 | { |
24f1e32c FW |
566 | int cpu; |
567 | struct perf_event **pevent; | |
62a038d3 | 568 | |
24f1e32c FW |
569 | for_each_possible_cpu(cpu) { |
570 | pevent = per_cpu_ptr(cpu_events, cpu); | |
571 | unregister_hw_breakpoint(*pevent); | |
62a038d3 | 572 | } |
24f1e32c | 573 | free_percpu(cpu_events); |
62a038d3 | 574 | } |
f60d24d2 | 575 | EXPORT_SYMBOL_GPL(unregister_wide_hw_breakpoint); |
62a038d3 P |
576 | |
577 | static struct notifier_block hw_breakpoint_exceptions_nb = { | |
578 | .notifier_call = hw_breakpoint_exceptions_notify, | |
579 | /* we need to be notified first */ | |
580 | .priority = 0x7fffffff | |
581 | }; | |
582 | ||
b0a873eb PZ |
583 | static void bp_perf_event_destroy(struct perf_event *event) |
584 | { | |
585 | release_bp_slot(event); | |
586 | } | |
587 | ||
588 | static int hw_breakpoint_event_init(struct perf_event *bp) | |
589 | { | |
590 | int err; | |
591 | ||
592 | if (bp->attr.type != PERF_TYPE_BREAKPOINT) | |
593 | return -ENOENT; | |
594 | ||
2481c5fa SE |
595 | /* |
596 | * no branch sampling for breakpoint events | |
597 | */ | |
598 | if (has_branch_stack(bp)) | |
599 | return -EOPNOTSUPP; | |
600 | ||
b0a873eb PZ |
601 | err = register_perf_hw_breakpoint(bp); |
602 | if (err) | |
603 | return err; | |
604 | ||
605 | bp->destroy = bp_perf_event_destroy; | |
606 | ||
607 | return 0; | |
608 | } | |
609 | ||
a4eaf7f1 PZ |
610 | static int hw_breakpoint_add(struct perf_event *bp, int flags) |
611 | { | |
612 | if (!(flags & PERF_EF_START)) | |
613 | bp->hw.state = PERF_HES_STOPPED; | |
614 | ||
615 | return arch_install_hw_breakpoint(bp); | |
616 | } | |
617 | ||
618 | static void hw_breakpoint_del(struct perf_event *bp, int flags) | |
619 | { | |
620 | arch_uninstall_hw_breakpoint(bp); | |
621 | } | |
622 | ||
623 | static void hw_breakpoint_start(struct perf_event *bp, int flags) | |
624 | { | |
625 | bp->hw.state = 0; | |
626 | } | |
627 | ||
628 | static void hw_breakpoint_stop(struct perf_event *bp, int flags) | |
629 | { | |
630 | bp->hw.state = PERF_HES_STOPPED; | |
631 | } | |
632 | ||
35edc2a5 PZ |
633 | static int hw_breakpoint_event_idx(struct perf_event *bp) |
634 | { | |
635 | return 0; | |
636 | } | |
637 | ||
b0a873eb | 638 | static struct pmu perf_breakpoint = { |
89a1e187 PZ |
639 | .task_ctx_nr = perf_sw_context, /* could eventually get its own */ |
640 | ||
b0a873eb | 641 | .event_init = hw_breakpoint_event_init, |
a4eaf7f1 PZ |
642 | .add = hw_breakpoint_add, |
643 | .del = hw_breakpoint_del, | |
644 | .start = hw_breakpoint_start, | |
645 | .stop = hw_breakpoint_stop, | |
b0a873eb | 646 | .read = hw_breakpoint_pmu_read, |
35edc2a5 PZ |
647 | |
648 | .event_idx = hw_breakpoint_event_idx, | |
b0a873eb PZ |
649 | }; |
650 | ||
3c502e7a | 651 | int __init init_hw_breakpoint(void) |
62a038d3 | 652 | { |
feef47d0 FW |
653 | unsigned int **task_bp_pinned; |
654 | int cpu, err_cpu; | |
655 | int i; | |
656 | ||
657 | for (i = 0; i < TYPE_MAX; i++) | |
658 | nr_slots[i] = hw_breakpoint_slots(i); | |
659 | ||
660 | for_each_possible_cpu(cpu) { | |
661 | for (i = 0; i < TYPE_MAX; i++) { | |
662 | task_bp_pinned = &per_cpu(nr_task_bp_pinned[i], cpu); | |
663 | *task_bp_pinned = kzalloc(sizeof(int) * nr_slots[i], | |
664 | GFP_KERNEL); | |
665 | if (!*task_bp_pinned) | |
666 | goto err_alloc; | |
667 | } | |
668 | } | |
669 | ||
670 | constraints_initialized = 1; | |
671 | ||
2e80a82a | 672 | perf_pmu_register(&perf_breakpoint, "breakpoint", PERF_TYPE_BREAKPOINT); |
b0a873eb | 673 | |
62a038d3 | 674 | return register_die_notifier(&hw_breakpoint_exceptions_nb); |
feef47d0 FW |
675 | |
676 | err_alloc: | |
677 | for_each_possible_cpu(err_cpu) { | |
feef47d0 | 678 | for (i = 0; i < TYPE_MAX; i++) |
02e176af | 679 | kfree(per_cpu(nr_task_bp_pinned[i], err_cpu)); |
30ce2f7e NK |
680 | if (err_cpu == cpu) |
681 | break; | |
feef47d0 FW |
682 | } |
683 | ||
684 | return -ENOMEM; | |
62a038d3 | 685 | } |
24f1e32c FW |
686 | |
687 |