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30#include <linux/perf_event.h>
31#include <linux/hw_breakpoint.h>
32#include <linux/irqflags.h>
33#include <linux/notifier.h>
34#include <linux/kallsyms.h>
35#include <linux/kprobes.h>
36#include <linux/percpu.h>
37#include <linux/kdebug.h>
38#include <linux/kernel.h>
39#include <linux/export.h>
40#include <linux/sched.h>
41#include <linux/smp.h>
42
43#include <asm/hw_breakpoint.h>
44#include <asm/processor.h>
45#include <asm/debugreg.h>
46#include <asm/user.h>
47
48
49DEFINE_PER_CPU(unsigned long, cpu_dr7);
50EXPORT_PER_CPU_SYMBOL(cpu_dr7);
51
52
53static DEFINE_PER_CPU(unsigned long, cpu_debugreg[HBP_NUM]);
54
55
56
57
58
59static DEFINE_PER_CPU(struct perf_event *, bp_per_reg[HBP_NUM]);
60
61
62static inline unsigned long
63__encode_dr7(int drnum, unsigned int len, unsigned int type)
64{
65 unsigned long bp_info;
66
67 bp_info = (len | type) & 0xf;
68 bp_info <<= (DR_CONTROL_SHIFT + drnum * DR_CONTROL_SIZE);
69 bp_info |= (DR_GLOBAL_ENABLE << (drnum * DR_ENABLE_SIZE));
70
71 return bp_info;
72}
73
74
75
76
77
78unsigned long encode_dr7(int drnum, unsigned int len, unsigned int type)
79{
80 return __encode_dr7(drnum, len, type) | DR_GLOBAL_SLOWDOWN;
81}
82
83
84
85
86
87int decode_dr7(unsigned long dr7, int bpnum, unsigned *len, unsigned *type)
88{
89 int bp_info = dr7 >> (DR_CONTROL_SHIFT + bpnum * DR_CONTROL_SIZE);
90
91 *len = (bp_info & 0xc) | 0x40;
92 *type = (bp_info & 0x3) | 0x80;
93
94 return (dr7 >> (bpnum * DR_ENABLE_SIZE)) & 0x3;
95}
96
97
98
99
100
101
102
103
104
105
106int arch_install_hw_breakpoint(struct perf_event *bp)
107{
108 struct arch_hw_breakpoint *info = counter_arch_bp(bp);
109 unsigned long *dr7;
110 int i;
111
112 for (i = 0; i < HBP_NUM; i++) {
113 struct perf_event **slot = this_cpu_ptr(&bp_per_reg[i]);
114
115 if (!*slot) {
116 *slot = bp;
117 break;
118 }
119 }
120
121 if (WARN_ONCE(i == HBP_NUM, "Can't find any breakpoint slot"))
122 return -EBUSY;
123
124 set_debugreg(info->address, i);
125 __this_cpu_write(cpu_debugreg[i], info->address);
126
127 dr7 = this_cpu_ptr(&cpu_dr7);
128 *dr7 |= encode_dr7(i, info->len, info->type);
129
130 set_debugreg(*dr7, 7);
131 if (info->mask)
132 set_dr_addr_mask(info->mask, i);
133
134 return 0;
135}
136
137
138
139
140
141
142
143
144
145
146void arch_uninstall_hw_breakpoint(struct perf_event *bp)
147{
148 struct arch_hw_breakpoint *info = counter_arch_bp(bp);
149 unsigned long *dr7;
150 int i;
151
152 for (i = 0; i < HBP_NUM; i++) {
153 struct perf_event **slot = this_cpu_ptr(&bp_per_reg[i]);
154
155 if (*slot == bp) {
156 *slot = NULL;
157 break;
158 }
159 }
160
161 if (WARN_ONCE(i == HBP_NUM, "Can't find any breakpoint slot"))
162 return;
163
164 dr7 = this_cpu_ptr(&cpu_dr7);
165 *dr7 &= ~__encode_dr7(i, info->len, info->type);
166
167 set_debugreg(*dr7, 7);
168 if (info->mask)
169 set_dr_addr_mask(0, i);
170}
171
172
173
174
175int arch_check_bp_in_kernelspace(struct perf_event *bp)
176{
177 unsigned int len;
178 unsigned long va;
179 struct arch_hw_breakpoint *info = counter_arch_bp(bp);
180
181 va = info->address;
182 len = bp->attr.bp_len;
183
184
185
186
187
188 return (va >= TASK_SIZE_MAX) || ((va + len - 1) >= TASK_SIZE_MAX);
189}
190
191int arch_bp_generic_fields(int x86_len, int x86_type,
192 int *gen_len, int *gen_type)
193{
194
195 switch (x86_type) {
196 case X86_BREAKPOINT_EXECUTE:
197 if (x86_len != X86_BREAKPOINT_LEN_X)
198 return -EINVAL;
199
200 *gen_type = HW_BREAKPOINT_X;
201 *gen_len = sizeof(long);
202 return 0;
203 case X86_BREAKPOINT_WRITE:
204 *gen_type = HW_BREAKPOINT_W;
205 break;
206 case X86_BREAKPOINT_RW:
207 *gen_type = HW_BREAKPOINT_W | HW_BREAKPOINT_R;
208 break;
209 default:
210 return -EINVAL;
211 }
212
213
214 switch (x86_len) {
215 case X86_BREAKPOINT_LEN_1:
216 *gen_len = HW_BREAKPOINT_LEN_1;
217 break;
218 case X86_BREAKPOINT_LEN_2:
219 *gen_len = HW_BREAKPOINT_LEN_2;
220 break;
221 case X86_BREAKPOINT_LEN_4:
222 *gen_len = HW_BREAKPOINT_LEN_4;
223 break;
224#ifdef CONFIG_X86_64
225 case X86_BREAKPOINT_LEN_8:
226 *gen_len = HW_BREAKPOINT_LEN_8;
227 break;
228#endif
229 default:
230 return -EINVAL;
231 }
232
233 return 0;
234}
235
236
237static int arch_build_bp_info(struct perf_event *bp)
238{
239 struct arch_hw_breakpoint *info = counter_arch_bp(bp);
240
241 info->address = bp->attr.bp_addr;
242
243
244 switch (bp->attr.bp_type) {
245 case HW_BREAKPOINT_W:
246 info->type = X86_BREAKPOINT_WRITE;
247 break;
248 case HW_BREAKPOINT_W | HW_BREAKPOINT_R:
249 info->type = X86_BREAKPOINT_RW;
250 break;
251 case HW_BREAKPOINT_X:
252
253
254
255
256
257 if (bp->attr.bp_addr >= TASK_SIZE_MAX) {
258#ifdef CONFIG_KPROBES
259 if (within_kprobe_blacklist(bp->attr.bp_addr))
260 return -EINVAL;
261#else
262 return -EINVAL;
263#endif
264 }
265
266 info->type = X86_BREAKPOINT_EXECUTE;
267
268
269
270
271
272 if (bp->attr.bp_len == sizeof(long)) {
273 info->len = X86_BREAKPOINT_LEN_X;
274 return 0;
275 }
276 default:
277 return -EINVAL;
278 }
279
280
281 info->mask = 0;
282
283 switch (bp->attr.bp_len) {
284 case HW_BREAKPOINT_LEN_1:
285 info->len = X86_BREAKPOINT_LEN_1;
286 break;
287 case HW_BREAKPOINT_LEN_2:
288 info->len = X86_BREAKPOINT_LEN_2;
289 break;
290 case HW_BREAKPOINT_LEN_4:
291 info->len = X86_BREAKPOINT_LEN_4;
292 break;
293#ifdef CONFIG_X86_64
294 case HW_BREAKPOINT_LEN_8:
295 info->len = X86_BREAKPOINT_LEN_8;
296 break;
297#endif
298 default:
299
300 if (!is_power_of_2(bp->attr.bp_len))
301 return -EINVAL;
302 if (bp->attr.bp_addr & (bp->attr.bp_len - 1))
303 return -EINVAL;
304
305 if (!boot_cpu_has(X86_FEATURE_BPEXT))
306 return -EOPNOTSUPP;
307
308
309
310
311
312
313
314
315 info->mask = bp->attr.bp_len - 1;
316 info->len = X86_BREAKPOINT_LEN_1;
317 }
318
319 return 0;
320}
321
322
323
324
325int arch_validate_hwbkpt_settings(struct perf_event *bp)
326{
327 struct arch_hw_breakpoint *info = counter_arch_bp(bp);
328 unsigned int align;
329 int ret;
330
331
332 ret = arch_build_bp_info(bp);
333 if (ret)
334 return ret;
335
336 switch (info->len) {
337 case X86_BREAKPOINT_LEN_1:
338 align = 0;
339 if (info->mask)
340 align = info->mask;
341 break;
342 case X86_BREAKPOINT_LEN_2:
343 align = 1;
344 break;
345 case X86_BREAKPOINT_LEN_4:
346 align = 3;
347 break;
348#ifdef CONFIG_X86_64
349 case X86_BREAKPOINT_LEN_8:
350 align = 7;
351 break;
352#endif
353 default:
354 WARN_ON_ONCE(1);
355 }
356
357
358
359
360
361 if (info->address & align)
362 return -EINVAL;
363
364 return 0;
365}
366
367
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371
372
373
374
375void aout_dump_debugregs(struct user *dump)
376{
377 int i;
378 int dr7 = 0;
379 struct perf_event *bp;
380 struct arch_hw_breakpoint *info;
381 struct thread_struct *thread = ¤t->thread;
382
383 for (i = 0; i < HBP_NUM; i++) {
384 bp = thread->ptrace_bps[i];
385
386 if (bp && !bp->attr.disabled) {
387 dump->u_debugreg[i] = bp->attr.bp_addr;
388 info = counter_arch_bp(bp);
389 dr7 |= encode_dr7(i, info->len, info->type);
390 } else {
391 dump->u_debugreg[i] = 0;
392 }
393 }
394
395 dump->u_debugreg[4] = 0;
396 dump->u_debugreg[5] = 0;
397 dump->u_debugreg[6] = current->thread.debugreg6;
398
399 dump->u_debugreg[7] = dr7;
400}
401EXPORT_SYMBOL_GPL(aout_dump_debugregs);
402
403
404
405
406void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
407{
408 int i;
409 struct thread_struct *t = &tsk->thread;
410
411 for (i = 0; i < HBP_NUM; i++) {
412 unregister_hw_breakpoint(t->ptrace_bps[i]);
413 t->ptrace_bps[i] = NULL;
414 }
415
416 t->debugreg6 = 0;
417 t->ptrace_dr7 = 0;
418}
419
420void hw_breakpoint_restore(void)
421{
422 set_debugreg(__this_cpu_read(cpu_debugreg[0]), 0);
423 set_debugreg(__this_cpu_read(cpu_debugreg[1]), 1);
424 set_debugreg(__this_cpu_read(cpu_debugreg[2]), 2);
425 set_debugreg(__this_cpu_read(cpu_debugreg[3]), 3);
426 set_debugreg(current->thread.debugreg6, 6);
427 set_debugreg(__this_cpu_read(cpu_dr7), 7);
428}
429EXPORT_SYMBOL_GPL(hw_breakpoint_restore);
430
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445
446
447static int hw_breakpoint_handler(struct die_args *args)
448{
449 int i, cpu, rc = NOTIFY_STOP;
450 struct perf_event *bp;
451 unsigned long dr7, dr6;
452 unsigned long *dr6_p;
453
454
455 dr6_p = (unsigned long *)ERR_PTR(args->err);
456 dr6 = *dr6_p;
457
458
459 if (dr6 & DR_STEP)
460 return NOTIFY_DONE;
461
462
463 if ((dr6 & DR_TRAP_BITS) == 0)
464 return NOTIFY_DONE;
465
466 get_debugreg(dr7, 7);
467
468 set_debugreg(0UL, 7);
469
470
471
472
473
474 current->thread.debugreg6 &= ~DR_TRAP_BITS;
475 cpu = get_cpu();
476
477
478 for (i = 0; i < HBP_NUM; ++i) {
479 if (likely(!(dr6 & (DR_TRAP0 << i))))
480 continue;
481
482
483
484
485
486
487
488 rcu_read_lock();
489
490 bp = per_cpu(bp_per_reg[i], cpu);
491
492
493
494
495 (*dr6_p) &= ~(DR_TRAP0 << i);
496
497
498
499
500 if (!bp) {
501 rcu_read_unlock();
502 break;
503 }
504
505 perf_bp_event(bp, args->regs);
506
507
508
509
510
511 if (bp->hw.info.type == X86_BREAKPOINT_EXECUTE)
512 args->regs->flags |= X86_EFLAGS_RF;
513
514 rcu_read_unlock();
515 }
516
517
518
519
520
521 if ((current->thread.debugreg6 & DR_TRAP_BITS) ||
522 (dr6 & (~DR_TRAP_BITS)))
523 rc = NOTIFY_DONE;
524
525 set_debugreg(dr7, 7);
526 put_cpu();
527
528 return rc;
529}
530
531
532
533
534int hw_breakpoint_exceptions_notify(
535 struct notifier_block *unused, unsigned long val, void *data)
536{
537 if (val != DIE_DEBUG)
538 return NOTIFY_DONE;
539
540 return hw_breakpoint_handler(data);
541}
542
543void hw_breakpoint_pmu_read(struct perf_event *bp)
544{
545
546}
547