Commit | Line | Data |
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0067f129 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) 2009 IBM Corporation | |
24f1e32c | 18 | * Copyright (C) 2009 Frederic Weisbecker <fweisbec@gmail.com> |
ba6909b7 P |
19 | * |
20 | * Authors: Alan Stern <stern@rowland.harvard.edu> | |
21 | * K.Prasad <prasad@linux.vnet.ibm.com> | |
22 | * Frederic Weisbecker <fweisbec@gmail.com> | |
0067f129 P |
23 | */ |
24 | ||
25 | /* | |
26 | * HW_breakpoint: a unified kernel/user-space hardware breakpoint facility, | |
27 | * using the CPU's debug registers. | |
28 | */ | |
29 | ||
24f1e32c FW |
30 | #include <linux/perf_event.h> |
31 | #include <linux/hw_breakpoint.h> | |
0067f129 P |
32 | #include <linux/irqflags.h> |
33 | #include <linux/notifier.h> | |
34 | #include <linux/kallsyms.h> | |
e5779e8e | 35 | #include <linux/kprobes.h> |
0067f129 P |
36 | #include <linux/percpu.h> |
37 | #include <linux/kdebug.h> | |
38 | #include <linux/kernel.h> | |
39 | #include <linux/module.h> | |
40 | #include <linux/sched.h> | |
0067f129 P |
41 | #include <linux/smp.h> |
42 | ||
43 | #include <asm/hw_breakpoint.h> | |
44 | #include <asm/processor.h> | |
45 | #include <asm/debugreg.h> | |
46 | ||
24f1e32c | 47 | /* Per cpu debug control register value */ |
28b4e0d8 TH |
48 | DEFINE_PER_CPU(unsigned long, cpu_dr7); |
49 | EXPORT_PER_CPU_SYMBOL(cpu_dr7); | |
24f1e32c FW |
50 | |
51 | /* Per cpu debug address registers values */ | |
52 | static DEFINE_PER_CPU(unsigned long, cpu_debugreg[HBP_NUM]); | |
0067f129 P |
53 | |
54 | /* | |
24f1e32c FW |
55 | * Stores the breakpoints currently in use on each breakpoint address |
56 | * register for each cpus | |
0067f129 | 57 | */ |
24f1e32c | 58 | static DEFINE_PER_CPU(struct perf_event *, bp_per_reg[HBP_NUM]); |
0067f129 P |
59 | |
60 | ||
2c31b795 FW |
61 | static inline unsigned long |
62 | __encode_dr7(int drnum, unsigned int len, unsigned int type) | |
0067f129 P |
63 | { |
64 | unsigned long bp_info; | |
65 | ||
66 | bp_info = (len | type) & 0xf; | |
67 | bp_info <<= (DR_CONTROL_SHIFT + drnum * DR_CONTROL_SIZE); | |
2c31b795 FW |
68 | bp_info |= (DR_GLOBAL_ENABLE << (drnum * DR_ENABLE_SIZE)); |
69 | ||
0067f129 P |
70 | return bp_info; |
71 | } | |
72 | ||
2c31b795 FW |
73 | /* |
74 | * Encode the length, type, Exact, and Enable bits for a particular breakpoint | |
75 | * as stored in debug register 7. | |
76 | */ | |
77 | unsigned long encode_dr7(int drnum, unsigned int len, unsigned int type) | |
78 | { | |
79 | return __encode_dr7(drnum, len, type) | DR_GLOBAL_SLOWDOWN; | |
80 | } | |
81 | ||
24f1e32c FW |
82 | /* |
83 | * Decode the length and type bits for a particular breakpoint as | |
84 | * stored in debug register 7. Return the "enabled" status. | |
85 | */ | |
86 | int decode_dr7(unsigned long dr7, int bpnum, unsigned *len, unsigned *type) | |
0067f129 | 87 | { |
24f1e32c | 88 | int bp_info = dr7 >> (DR_CONTROL_SHIFT + bpnum * DR_CONTROL_SIZE); |
0067f129 | 89 | |
24f1e32c FW |
90 | *len = (bp_info & 0xc) | 0x40; |
91 | *type = (bp_info & 0x3) | 0x80; | |
0067f129 | 92 | |
24f1e32c | 93 | return (dr7 >> (bpnum * DR_ENABLE_SIZE)) & 0x3; |
0067f129 P |
94 | } |
95 | ||
96 | /* | |
24f1e32c FW |
97 | * Install a perf counter breakpoint. |
98 | * | |
99 | * We seek a free debug address register and use it for this | |
100 | * breakpoint. Eventually we enable it in the debug control register. | |
101 | * | |
102 | * Atomic: we hold the counter->ctx->lock and we only handle variables | |
103 | * and registers local to this cpu. | |
0067f129 | 104 | */ |
24f1e32c | 105 | int arch_install_hw_breakpoint(struct perf_event *bp) |
0067f129 | 106 | { |
24f1e32c FW |
107 | struct arch_hw_breakpoint *info = counter_arch_bp(bp); |
108 | unsigned long *dr7; | |
109 | int i; | |
110 | ||
111 | for (i = 0; i < HBP_NUM; i++) { | |
89cbc767 | 112 | struct perf_event **slot = this_cpu_ptr(&bp_per_reg[i]); |
24f1e32c FW |
113 | |
114 | if (!*slot) { | |
115 | *slot = bp; | |
116 | break; | |
117 | } | |
0067f129 P |
118 | } |
119 | ||
24f1e32c FW |
120 | if (WARN_ONCE(i == HBP_NUM, "Can't find any breakpoint slot")) |
121 | return -EBUSY; | |
122 | ||
123 | set_debugreg(info->address, i); | |
0a3aee0d | 124 | __this_cpu_write(cpu_debugreg[i], info->address); |
24f1e32c | 125 | |
89cbc767 | 126 | dr7 = this_cpu_ptr(&cpu_dr7); |
24f1e32c FW |
127 | *dr7 |= encode_dr7(i, info->len, info->type); |
128 | ||
129 | set_debugreg(*dr7, 7); | |
d6d55f0b JS |
130 | if (info->mask) |
131 | set_dr_addr_mask(info->mask, i); | |
24f1e32c FW |
132 | |
133 | return 0; | |
0067f129 P |
134 | } |
135 | ||
136 | /* | |
24f1e32c FW |
137 | * Uninstall the breakpoint contained in the given counter. |
138 | * | |
139 | * First we search the debug address register it uses and then we disable | |
140 | * it. | |
141 | * | |
142 | * Atomic: we hold the counter->ctx->lock and we only handle variables | |
143 | * and registers local to this cpu. | |
0067f129 | 144 | */ |
24f1e32c | 145 | void arch_uninstall_hw_breakpoint(struct perf_event *bp) |
0067f129 | 146 | { |
24f1e32c FW |
147 | struct arch_hw_breakpoint *info = counter_arch_bp(bp); |
148 | unsigned long *dr7; | |
149 | int i; | |
150 | ||
151 | for (i = 0; i < HBP_NUM; i++) { | |
89cbc767 | 152 | struct perf_event **slot = this_cpu_ptr(&bp_per_reg[i]); |
24f1e32c FW |
153 | |
154 | if (*slot == bp) { | |
155 | *slot = NULL; | |
156 | break; | |
157 | } | |
158 | } | |
159 | ||
160 | if (WARN_ONCE(i == HBP_NUM, "Can't find any breakpoint slot")) | |
161 | return; | |
0067f129 | 162 | |
89cbc767 | 163 | dr7 = this_cpu_ptr(&cpu_dr7); |
2c31b795 | 164 | *dr7 &= ~__encode_dr7(i, info->len, info->type); |
24f1e32c FW |
165 | |
166 | set_debugreg(*dr7, 7); | |
d6d55f0b JS |
167 | if (info->mask) |
168 | set_dr_addr_mask(0, i); | |
0067f129 P |
169 | } |
170 | ||
0067f129 P |
171 | /* |
172 | * Check for virtual address in kernel space. | |
173 | */ | |
b2812d03 | 174 | int arch_check_bp_in_kernelspace(struct perf_event *bp) |
0067f129 P |
175 | { |
176 | unsigned int len; | |
b2812d03 FW |
177 | unsigned long va; |
178 | struct arch_hw_breakpoint *info = counter_arch_bp(bp); | |
0067f129 | 179 | |
b2812d03 | 180 | va = info->address; |
36748b95 | 181 | len = bp->attr.bp_len; |
0067f129 P |
182 | |
183 | return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE); | |
184 | } | |
185 | ||
24f1e32c FW |
186 | int arch_bp_generic_fields(int x86_len, int x86_type, |
187 | int *gen_len, int *gen_type) | |
0067f129 | 188 | { |
89e45aac FW |
189 | /* Type */ |
190 | switch (x86_type) { | |
191 | case X86_BREAKPOINT_EXECUTE: | |
192 | if (x86_len != X86_BREAKPOINT_LEN_X) | |
193 | return -EINVAL; | |
194 | ||
195 | *gen_type = HW_BREAKPOINT_X; | |
f7809daf | 196 | *gen_len = sizeof(long); |
89e45aac FW |
197 | return 0; |
198 | case X86_BREAKPOINT_WRITE: | |
199 | *gen_type = HW_BREAKPOINT_W; | |
f7809daf | 200 | break; |
89e45aac FW |
201 | case X86_BREAKPOINT_RW: |
202 | *gen_type = HW_BREAKPOINT_W | HW_BREAKPOINT_R; | |
203 | break; | |
204 | default: | |
205 | return -EINVAL; | |
206 | } | |
207 | ||
208 | /* Len */ | |
209 | switch (x86_len) { | |
24f1e32c FW |
210 | case X86_BREAKPOINT_LEN_1: |
211 | *gen_len = HW_BREAKPOINT_LEN_1; | |
212 | break; | |
213 | case X86_BREAKPOINT_LEN_2: | |
214 | *gen_len = HW_BREAKPOINT_LEN_2; | |
215 | break; | |
216 | case X86_BREAKPOINT_LEN_4: | |
217 | *gen_len = HW_BREAKPOINT_LEN_4; | |
218 | break; | |
219 | #ifdef CONFIG_X86_64 | |
220 | case X86_BREAKPOINT_LEN_8: | |
221 | *gen_len = HW_BREAKPOINT_LEN_8; | |
222 | break; | |
223 | #endif | |
224 | default: | |
225 | return -EINVAL; | |
226 | } | |
0067f129 | 227 | |
24f1e32c FW |
228 | return 0; |
229 | } | |
230 | ||
231 | ||
232 | static int arch_build_bp_info(struct perf_event *bp) | |
233 | { | |
234 | struct arch_hw_breakpoint *info = counter_arch_bp(bp); | |
235 | ||
236 | info->address = bp->attr.bp_addr; | |
237 | ||
f7809daf FW |
238 | /* Type */ |
239 | switch (bp->attr.bp_type) { | |
240 | case HW_BREAKPOINT_W: | |
241 | info->type = X86_BREAKPOINT_WRITE; | |
242 | break; | |
243 | case HW_BREAKPOINT_W | HW_BREAKPOINT_R: | |
244 | info->type = X86_BREAKPOINT_RW; | |
245 | break; | |
246 | case HW_BREAKPOINT_X: | |
e5779e8e AL |
247 | /* |
248 | * We don't allow kernel breakpoints in places that are not | |
249 | * acceptable for kprobes. On non-kprobes kernels, we don't | |
250 | * allow kernel breakpoints at all. | |
251 | */ | |
252 | if (bp->attr.bp_addr >= TASK_SIZE_MAX) { | |
253 | #ifdef CONFIG_KPROBES | |
254 | if (within_kprobe_blacklist(bp->attr.bp_addr)) | |
255 | return -EINVAL; | |
256 | #else | |
257 | return -EINVAL; | |
258 | #endif | |
259 | } | |
260 | ||
f7809daf FW |
261 | info->type = X86_BREAKPOINT_EXECUTE; |
262 | /* | |
263 | * x86 inst breakpoints need to have a specific undefined len. | |
264 | * But we still need to check userspace is not trying to setup | |
265 | * an unsupported length, to get a range breakpoint for example. | |
266 | */ | |
267 | if (bp->attr.bp_len == sizeof(long)) { | |
268 | info->len = X86_BREAKPOINT_LEN_X; | |
269 | return 0; | |
270 | } | |
271 | default: | |
272 | return -EINVAL; | |
273 | } | |
274 | ||
24f1e32c | 275 | /* Len */ |
d6d55f0b JS |
276 | info->mask = 0; |
277 | ||
24f1e32c | 278 | switch (bp->attr.bp_len) { |
0067f129 | 279 | case HW_BREAKPOINT_LEN_1: |
24f1e32c | 280 | info->len = X86_BREAKPOINT_LEN_1; |
0067f129 P |
281 | break; |
282 | case HW_BREAKPOINT_LEN_2: | |
24f1e32c | 283 | info->len = X86_BREAKPOINT_LEN_2; |
0067f129 P |
284 | break; |
285 | case HW_BREAKPOINT_LEN_4: | |
24f1e32c | 286 | info->len = X86_BREAKPOINT_LEN_4; |
0067f129 P |
287 | break; |
288 | #ifdef CONFIG_X86_64 | |
289 | case HW_BREAKPOINT_LEN_8: | |
24f1e32c FW |
290 | info->len = X86_BREAKPOINT_LEN_8; |
291 | break; | |
292 | #endif | |
293 | default: | |
ab513927 | 294 | /* AMD range breakpoint */ |
d6d55f0b JS |
295 | if (!is_power_of_2(bp->attr.bp_len)) |
296 | return -EINVAL; | |
ab513927 AL |
297 | if (bp->attr.bp_addr & (bp->attr.bp_len - 1)) |
298 | return -EINVAL; | |
299 | /* | |
300 | * It's impossible to use a range breakpoint to fake out | |
301 | * user vs kernel detection because bp_len - 1 can't | |
302 | * have the high bit set. If we ever allow range instruction | |
303 | * breakpoints, then we'll have to check for kprobe-blacklisted | |
304 | * addresses anywhere in the range. | |
305 | */ | |
d6d55f0b JS |
306 | if (!cpu_has_bpext) |
307 | return -EOPNOTSUPP; | |
308 | info->mask = bp->attr.bp_len - 1; | |
309 | info->len = X86_BREAKPOINT_LEN_1; | |
24f1e32c FW |
310 | } |
311 | ||
24f1e32c FW |
312 | return 0; |
313 | } | |
d6d55f0b | 314 | |
24f1e32c FW |
315 | /* |
316 | * Validate the arch-specific HW Breakpoint register settings | |
317 | */ | |
b2812d03 | 318 | int arch_validate_hwbkpt_settings(struct perf_event *bp) |
24f1e32c FW |
319 | { |
320 | struct arch_hw_breakpoint *info = counter_arch_bp(bp); | |
321 | unsigned int align; | |
322 | int ret; | |
323 | ||
324 | ||
325 | ret = arch_build_bp_info(bp); | |
326 | if (ret) | |
327 | return ret; | |
328 | ||
24f1e32c FW |
329 | switch (info->len) { |
330 | case X86_BREAKPOINT_LEN_1: | |
331 | align = 0; | |
d6d55f0b JS |
332 | if (info->mask) |
333 | align = info->mask; | |
24f1e32c FW |
334 | break; |
335 | case X86_BREAKPOINT_LEN_2: | |
336 | align = 1; | |
337 | break; | |
338 | case X86_BREAKPOINT_LEN_4: | |
339 | align = 3; | |
340 | break; | |
341 | #ifdef CONFIG_X86_64 | |
342 | case X86_BREAKPOINT_LEN_8: | |
0067f129 P |
343 | align = 7; |
344 | break; | |
345 | #endif | |
346 | default: | |
d6d55f0b | 347 | WARN_ON_ONCE(1); |
0067f129 P |
348 | } |
349 | ||
0067f129 P |
350 | /* |
351 | * Check that the low-order bits of the address are appropriate | |
352 | * for the alignment implied by len. | |
353 | */ | |
24f1e32c | 354 | if (info->address & align) |
0067f129 P |
355 | return -EINVAL; |
356 | ||
0067f129 P |
357 | return 0; |
358 | } | |
359 | ||
9f6b3c2c FW |
360 | /* |
361 | * Dump the debug register contents to the user. | |
362 | * We can't dump our per cpu values because it | |
363 | * may contain cpu wide breakpoint, something that | |
364 | * doesn't belong to the current task. | |
365 | * | |
366 | * TODO: include non-ptrace user breakpoints (perf) | |
367 | */ | |
368 | void aout_dump_debugregs(struct user *dump) | |
369 | { | |
370 | int i; | |
371 | int dr7 = 0; | |
372 | struct perf_event *bp; | |
373 | struct arch_hw_breakpoint *info; | |
374 | struct thread_struct *thread = ¤t->thread; | |
375 | ||
376 | for (i = 0; i < HBP_NUM; i++) { | |
377 | bp = thread->ptrace_bps[i]; | |
378 | ||
379 | if (bp && !bp->attr.disabled) { | |
380 | dump->u_debugreg[i] = bp->attr.bp_addr; | |
381 | info = counter_arch_bp(bp); | |
382 | dr7 |= encode_dr7(i, info->len, info->type); | |
383 | } else { | |
384 | dump->u_debugreg[i] = 0; | |
385 | } | |
386 | } | |
387 | ||
388 | dump->u_debugreg[4] = 0; | |
389 | dump->u_debugreg[5] = 0; | |
390 | dump->u_debugreg[6] = current->thread.debugreg6; | |
391 | ||
392 | dump->u_debugreg[7] = dr7; | |
393 | } | |
68efa37d | 394 | EXPORT_SYMBOL_GPL(aout_dump_debugregs); |
9f6b3c2c | 395 | |
24f1e32c FW |
396 | /* |
397 | * Release the user breakpoints used by ptrace | |
398 | */ | |
399 | void flush_ptrace_hw_breakpoint(struct task_struct *tsk) | |
0067f129 | 400 | { |
24f1e32c FW |
401 | int i; |
402 | struct thread_struct *t = &tsk->thread; | |
403 | ||
404 | for (i = 0; i < HBP_NUM; i++) { | |
405 | unregister_hw_breakpoint(t->ptrace_bps[i]); | |
406 | t->ptrace_bps[i] = NULL; | |
407 | } | |
f7da04c9 ON |
408 | |
409 | t->debugreg6 = 0; | |
410 | t->ptrace_dr7 = 0; | |
0067f129 P |
411 | } |
412 | ||
24f1e32c | 413 | void hw_breakpoint_restore(void) |
0067f129 | 414 | { |
0a3aee0d TH |
415 | set_debugreg(__this_cpu_read(cpu_debugreg[0]), 0); |
416 | set_debugreg(__this_cpu_read(cpu_debugreg[1]), 1); | |
417 | set_debugreg(__this_cpu_read(cpu_debugreg[2]), 2); | |
418 | set_debugreg(__this_cpu_read(cpu_debugreg[3]), 3); | |
24f1e32c | 419 | set_debugreg(current->thread.debugreg6, 6); |
0a3aee0d | 420 | set_debugreg(__this_cpu_read(cpu_dr7), 7); |
0067f129 | 421 | } |
24f1e32c | 422 | EXPORT_SYMBOL_GPL(hw_breakpoint_restore); |
0067f129 P |
423 | |
424 | /* | |
425 | * Handle debug exception notifications. | |
426 | * | |
427 | * Return value is either NOTIFY_STOP or NOTIFY_DONE as explained below. | |
428 | * | |
429 | * NOTIFY_DONE returned if one of the following conditions is true. | |
430 | * i) When the causative address is from user-space and the exception | |
431 | * is a valid one, i.e. not triggered as a result of lazy debug register | |
432 | * switching | |
433 | * ii) When there are more bits than trap<n> set in DR6 register (such | |
434 | * as BD, BS or BT) indicating that more than one debug condition is | |
435 | * met and requires some more action in do_debug(). | |
436 | * | |
437 | * NOTIFY_STOP returned for all other cases | |
438 | * | |
439 | */ | |
9c54b616 | 440 | static int hw_breakpoint_handler(struct die_args *args) |
0067f129 P |
441 | { |
442 | int i, cpu, rc = NOTIFY_STOP; | |
24f1e32c | 443 | struct perf_event *bp; |
62edab90 P |
444 | unsigned long dr7, dr6; |
445 | unsigned long *dr6_p; | |
446 | ||
447 | /* The DR6 value is pointed by args->err */ | |
448 | dr6_p = (unsigned long *)ERR_PTR(args->err); | |
449 | dr6 = *dr6_p; | |
0067f129 | 450 | |
6c0aca28 FW |
451 | /* If it's a single step, TRAP bits are random */ |
452 | if (dr6 & DR_STEP) | |
453 | return NOTIFY_DONE; | |
454 | ||
0067f129 P |
455 | /* Do an early return if no trap bits are set in DR6 */ |
456 | if ((dr6 & DR_TRAP_BITS) == 0) | |
457 | return NOTIFY_DONE; | |
458 | ||
0067f129 P |
459 | get_debugreg(dr7, 7); |
460 | /* Disable breakpoints during exception handling */ | |
461 | set_debugreg(0UL, 7); | |
462 | /* | |
463 | * Assert that local interrupts are disabled | |
464 | * Reset the DRn bits in the virtualized register value. | |
465 | * The ptrace trigger routine will add in whatever is needed. | |
466 | */ | |
467 | current->thread.debugreg6 &= ~DR_TRAP_BITS; | |
468 | cpu = get_cpu(); | |
469 | ||
470 | /* Handle all the breakpoints that were triggered */ | |
471 | for (i = 0; i < HBP_NUM; ++i) { | |
472 | if (likely(!(dr6 & (DR_TRAP0 << i)))) | |
473 | continue; | |
24f1e32c | 474 | |
0067f129 | 475 | /* |
24f1e32c FW |
476 | * The counter may be concurrently released but that can only |
477 | * occur from a call_rcu() path. We can then safely fetch | |
478 | * the breakpoint, use its callback, touch its counter | |
479 | * while we are in an rcu_read_lock() path. | |
0067f129 | 480 | */ |
24f1e32c FW |
481 | rcu_read_lock(); |
482 | ||
483 | bp = per_cpu(bp_per_reg[i], cpu); | |
62edab90 P |
484 | /* |
485 | * Reset the 'i'th TRAP bit in dr6 to denote completion of | |
486 | * exception handling | |
487 | */ | |
488 | (*dr6_p) &= ~(DR_TRAP0 << i); | |
0067f129 P |
489 | /* |
490 | * bp can be NULL due to lazy debug register switching | |
24f1e32c | 491 | * or due to concurrent perf counter removing. |
0067f129 | 492 | */ |
24f1e32c FW |
493 | if (!bp) { |
494 | rcu_read_unlock(); | |
495 | break; | |
496 | } | |
497 | ||
b326e956 | 498 | perf_bp_event(bp, args->regs); |
0067f129 | 499 | |
0c4519e8 FW |
500 | /* |
501 | * Set up resume flag to avoid breakpoint recursion when | |
502 | * returning back to origin. | |
503 | */ | |
504 | if (bp->hw.info.type == X86_BREAKPOINT_EXECUTE) | |
505 | args->regs->flags |= X86_EFLAGS_RF; | |
506 | ||
24f1e32c | 507 | rcu_read_unlock(); |
0067f129 | 508 | } |
e0e53db6 P |
509 | /* |
510 | * Further processing in do_debug() is needed for a) user-space | |
511 | * breakpoints (to generate signals) and b) when the system has | |
512 | * taken exception due to multiple causes | |
513 | */ | |
514 | if ((current->thread.debugreg6 & DR_TRAP_BITS) || | |
515 | (dr6 & (~DR_TRAP_BITS))) | |
0067f129 P |
516 | rc = NOTIFY_DONE; |
517 | ||
518 | set_debugreg(dr7, 7); | |
eadb8a09 | 519 | put_cpu(); |
24f1e32c | 520 | |
0067f129 P |
521 | return rc; |
522 | } | |
523 | ||
524 | /* | |
525 | * Handle debug exception notifications. | |
526 | */ | |
9c54b616 | 527 | int hw_breakpoint_exceptions_notify( |
0067f129 P |
528 | struct notifier_block *unused, unsigned long val, void *data) |
529 | { | |
530 | if (val != DIE_DEBUG) | |
531 | return NOTIFY_DONE; | |
532 | ||
533 | return hw_breakpoint_handler(data); | |
534 | } | |
24f1e32c FW |
535 | |
536 | void hw_breakpoint_pmu_read(struct perf_event *bp) | |
537 | { | |
538 | /* TODO */ | |
539 | } |