This source file includes following definitions.
- alloc_s390_insn_page
- free_s390_insn_page
- copy_instruction
- is_kernel_addr
- s390_get_insn_slot
- s390_free_insn_slot
- arch_prepare_kprobe
- arch_check_ftrace_location
- swap_instruction
- arch_arm_kprobe
- arch_disarm_kprobe
- arch_remove_kprobe
- enable_singlestep
- disable_singlestep
- push_kprobe
- pop_kprobe
- arch_prepare_kretprobe
- kprobe_reenter_check
- kprobe_handler
- kretprobe_trampoline_holder
- trampoline_probe_handler
- resume_execution
- post_kprobe_handler
- kprobe_trap_handler
- kprobe_fault_handler
- kprobe_exceptions_notify
- arch_init_kprobes
- arch_trampoline_kprobe
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9
10 #include <linux/kprobes.h>
11 #include <linux/ptrace.h>
12 #include <linux/preempt.h>
13 #include <linux/stop_machine.h>
14 #include <linux/kdebug.h>
15 #include <linux/uaccess.h>
16 #include <linux/extable.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 #include <linux/hardirq.h>
20 #include <linux/ftrace.h>
21 #include <asm/set_memory.h>
22 #include <asm/sections.h>
23 #include <asm/dis.h>
24
25 DEFINE_PER_CPU(struct kprobe *, current_kprobe);
26 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
27
28 struct kretprobe_blackpoint kretprobe_blacklist[] = { };
29
30 DEFINE_INSN_CACHE_OPS(s390_insn);
31
32 static int insn_page_in_use;
33 static char insn_page[PAGE_SIZE] __aligned(PAGE_SIZE);
34
35 static void *alloc_s390_insn_page(void)
36 {
37 if (xchg(&insn_page_in_use, 1) == 1)
38 return NULL;
39 set_memory_x((unsigned long) &insn_page, 1);
40 return &insn_page;
41 }
42
43 static void free_s390_insn_page(void *page)
44 {
45 set_memory_nx((unsigned long) page, 1);
46 xchg(&insn_page_in_use, 0);
47 }
48
49 struct kprobe_insn_cache kprobe_s390_insn_slots = {
50 .mutex = __MUTEX_INITIALIZER(kprobe_s390_insn_slots.mutex),
51 .alloc = alloc_s390_insn_page,
52 .free = free_s390_insn_page,
53 .pages = LIST_HEAD_INIT(kprobe_s390_insn_slots.pages),
54 .insn_size = MAX_INSN_SIZE,
55 };
56
57 static void copy_instruction(struct kprobe *p)
58 {
59 unsigned long ip = (unsigned long) p->addr;
60 s64 disp, new_disp;
61 u64 addr, new_addr;
62
63 if (ftrace_location(ip) == ip) {
64
65
66
67
68
69
70 ftrace_generate_nop_insn((struct ftrace_insn *)p->ainsn.insn);
71 p->ainsn.is_ftrace_insn = 1;
72 } else
73 memcpy(p->ainsn.insn, p->addr, insn_length(*p->addr >> 8));
74 p->opcode = p->ainsn.insn[0];
75 if (!probe_is_insn_relative_long(p->ainsn.insn))
76 return;
77
78
79
80
81
82
83
84 disp = *(s32 *)&p->ainsn.insn[1];
85 addr = (u64)(unsigned long)p->addr;
86 new_addr = (u64)(unsigned long)p->ainsn.insn;
87 new_disp = ((addr + (disp * 2)) - new_addr) / 2;
88 *(s32 *)&p->ainsn.insn[1] = new_disp;
89 }
90 NOKPROBE_SYMBOL(copy_instruction);
91
92 static inline int is_kernel_addr(void *addr)
93 {
94 return addr < (void *)_end;
95 }
96
97 static int s390_get_insn_slot(struct kprobe *p)
98 {
99
100
101
102
103
104 p->ainsn.insn = NULL;
105 if (is_kernel_addr(p->addr))
106 p->ainsn.insn = get_s390_insn_slot();
107 else if (is_module_addr(p->addr))
108 p->ainsn.insn = get_insn_slot();
109 return p->ainsn.insn ? 0 : -ENOMEM;
110 }
111 NOKPROBE_SYMBOL(s390_get_insn_slot);
112
113 static void s390_free_insn_slot(struct kprobe *p)
114 {
115 if (!p->ainsn.insn)
116 return;
117 if (is_kernel_addr(p->addr))
118 free_s390_insn_slot(p->ainsn.insn, 0);
119 else
120 free_insn_slot(p->ainsn.insn, 0);
121 p->ainsn.insn = NULL;
122 }
123 NOKPROBE_SYMBOL(s390_free_insn_slot);
124
125 int arch_prepare_kprobe(struct kprobe *p)
126 {
127 if ((unsigned long) p->addr & 0x01)
128 return -EINVAL;
129
130 if (probe_is_prohibited_opcode(p->addr))
131 return -EINVAL;
132 if (s390_get_insn_slot(p))
133 return -ENOMEM;
134 copy_instruction(p);
135 return 0;
136 }
137 NOKPROBE_SYMBOL(arch_prepare_kprobe);
138
139 int arch_check_ftrace_location(struct kprobe *p)
140 {
141 return 0;
142 }
143
144 struct swap_insn_args {
145 struct kprobe *p;
146 unsigned int arm_kprobe : 1;
147 };
148
149 static int swap_instruction(void *data)
150 {
151 struct swap_insn_args *args = data;
152 struct ftrace_insn new_insn, *insn;
153 struct kprobe *p = args->p;
154 size_t len;
155
156 new_insn.opc = args->arm_kprobe ? BREAKPOINT_INSTRUCTION : p->opcode;
157 len = sizeof(new_insn.opc);
158 if (!p->ainsn.is_ftrace_insn)
159 goto skip_ftrace;
160 len = sizeof(new_insn);
161 insn = (struct ftrace_insn *) p->addr;
162 if (args->arm_kprobe) {
163 if (is_ftrace_nop(insn))
164 new_insn.disp = KPROBE_ON_FTRACE_NOP;
165 else
166 new_insn.disp = KPROBE_ON_FTRACE_CALL;
167 } else {
168 ftrace_generate_call_insn(&new_insn, (unsigned long)p->addr);
169 if (insn->disp == KPROBE_ON_FTRACE_NOP)
170 ftrace_generate_nop_insn(&new_insn);
171 }
172 skip_ftrace:
173 s390_kernel_write(p->addr, &new_insn, len);
174 return 0;
175 }
176 NOKPROBE_SYMBOL(swap_instruction);
177
178 void arch_arm_kprobe(struct kprobe *p)
179 {
180 struct swap_insn_args args = {.p = p, .arm_kprobe = 1};
181
182 stop_machine_cpuslocked(swap_instruction, &args, NULL);
183 }
184 NOKPROBE_SYMBOL(arch_arm_kprobe);
185
186 void arch_disarm_kprobe(struct kprobe *p)
187 {
188 struct swap_insn_args args = {.p = p, .arm_kprobe = 0};
189
190 stop_machine_cpuslocked(swap_instruction, &args, NULL);
191 }
192 NOKPROBE_SYMBOL(arch_disarm_kprobe);
193
194 void arch_remove_kprobe(struct kprobe *p)
195 {
196 s390_free_insn_slot(p);
197 }
198 NOKPROBE_SYMBOL(arch_remove_kprobe);
199
200 static void enable_singlestep(struct kprobe_ctlblk *kcb,
201 struct pt_regs *regs,
202 unsigned long ip)
203 {
204 struct per_regs per_kprobe;
205
206
207 per_kprobe.control = PER_EVENT_IFETCH;
208 per_kprobe.start = ip;
209 per_kprobe.end = ip;
210
211
212 __ctl_store(kcb->kprobe_saved_ctl, 9, 11);
213 kcb->kprobe_saved_imask = regs->psw.mask &
214 (PSW_MASK_PER | PSW_MASK_IO | PSW_MASK_EXT);
215
216
217 __ctl_load(per_kprobe, 9, 11);
218 regs->psw.mask |= PSW_MASK_PER;
219 regs->psw.mask &= ~(PSW_MASK_IO | PSW_MASK_EXT);
220 regs->psw.addr = ip;
221 }
222 NOKPROBE_SYMBOL(enable_singlestep);
223
224 static void disable_singlestep(struct kprobe_ctlblk *kcb,
225 struct pt_regs *regs,
226 unsigned long ip)
227 {
228
229 __ctl_load(kcb->kprobe_saved_ctl, 9, 11);
230 regs->psw.mask &= ~PSW_MASK_PER;
231 regs->psw.mask |= kcb->kprobe_saved_imask;
232 regs->psw.addr = ip;
233 }
234 NOKPROBE_SYMBOL(disable_singlestep);
235
236
237
238
239
240
241 static void push_kprobe(struct kprobe_ctlblk *kcb, struct kprobe *p)
242 {
243 kcb->prev_kprobe.kp = __this_cpu_read(current_kprobe);
244 kcb->prev_kprobe.status = kcb->kprobe_status;
245 __this_cpu_write(current_kprobe, p);
246 }
247 NOKPROBE_SYMBOL(push_kprobe);
248
249
250
251
252
253
254 static void pop_kprobe(struct kprobe_ctlblk *kcb)
255 {
256 __this_cpu_write(current_kprobe, kcb->prev_kprobe.kp);
257 kcb->kprobe_status = kcb->prev_kprobe.status;
258 }
259 NOKPROBE_SYMBOL(pop_kprobe);
260
261 void arch_prepare_kretprobe(struct kretprobe_instance *ri, struct pt_regs *regs)
262 {
263 ri->ret_addr = (kprobe_opcode_t *) regs->gprs[14];
264
265
266 regs->gprs[14] = (unsigned long) &kretprobe_trampoline;
267 }
268 NOKPROBE_SYMBOL(arch_prepare_kretprobe);
269
270 static void kprobe_reenter_check(struct kprobe_ctlblk *kcb, struct kprobe *p)
271 {
272 switch (kcb->kprobe_status) {
273 case KPROBE_HIT_SSDONE:
274 case KPROBE_HIT_ACTIVE:
275 kprobes_inc_nmissed_count(p);
276 break;
277 case KPROBE_HIT_SS:
278 case KPROBE_REENTER:
279 default:
280
281
282
283
284
285 pr_err("Invalid kprobe detected.\n");
286 dump_kprobe(p);
287 BUG();
288 }
289 }
290 NOKPROBE_SYMBOL(kprobe_reenter_check);
291
292 static int kprobe_handler(struct pt_regs *regs)
293 {
294 struct kprobe_ctlblk *kcb;
295 struct kprobe *p;
296
297
298
299
300
301
302 preempt_disable();
303 kcb = get_kprobe_ctlblk();
304 p = get_kprobe((void *)(regs->psw.addr - 2));
305
306 if (p) {
307 if (kprobe_running()) {
308
309
310
311
312
313
314
315
316
317 kprobe_reenter_check(kcb, p);
318 push_kprobe(kcb, p);
319 kcb->kprobe_status = KPROBE_REENTER;
320 } else {
321
322
323
324
325
326
327
328 push_kprobe(kcb, p);
329 kcb->kprobe_status = KPROBE_HIT_ACTIVE;
330 if (p->pre_handler && p->pre_handler(p, regs)) {
331 pop_kprobe(kcb);
332 preempt_enable_no_resched();
333 return 1;
334 }
335 kcb->kprobe_status = KPROBE_HIT_SS;
336 }
337 enable_singlestep(kcb, regs, (unsigned long) p->ainsn.insn);
338 return 1;
339 }
340
341
342
343
344
345 preempt_enable_no_resched();
346 return 0;
347 }
348 NOKPROBE_SYMBOL(kprobe_handler);
349
350
351
352
353
354
355
356 static void __used kretprobe_trampoline_holder(void)
357 {
358 asm volatile(".global kretprobe_trampoline\n"
359 "kretprobe_trampoline: bcr 0,0\n");
360 }
361
362
363
364
365 static int trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
366 {
367 struct kretprobe_instance *ri;
368 struct hlist_head *head, empty_rp;
369 struct hlist_node *tmp;
370 unsigned long flags, orig_ret_address;
371 unsigned long trampoline_address;
372 kprobe_opcode_t *correct_ret_addr;
373
374 INIT_HLIST_HEAD(&empty_rp);
375 kretprobe_hash_lock(current, &head, &flags);
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390 ri = NULL;
391 orig_ret_address = 0;
392 correct_ret_addr = NULL;
393 trampoline_address = (unsigned long) &kretprobe_trampoline;
394 hlist_for_each_entry_safe(ri, tmp, head, hlist) {
395 if (ri->task != current)
396
397 continue;
398
399 orig_ret_address = (unsigned long) ri->ret_addr;
400
401 if (orig_ret_address != trampoline_address)
402
403
404
405
406
407 break;
408 }
409
410 kretprobe_assert(ri, orig_ret_address, trampoline_address);
411
412 correct_ret_addr = ri->ret_addr;
413 hlist_for_each_entry_safe(ri, tmp, head, hlist) {
414 if (ri->task != current)
415
416 continue;
417
418 orig_ret_address = (unsigned long) ri->ret_addr;
419
420 if (ri->rp && ri->rp->handler) {
421 ri->ret_addr = correct_ret_addr;
422 ri->rp->handler(ri, regs);
423 }
424
425 recycle_rp_inst(ri, &empty_rp);
426
427 if (orig_ret_address != trampoline_address)
428
429
430
431
432
433 break;
434 }
435
436 regs->psw.addr = orig_ret_address;
437
438 kretprobe_hash_unlock(current, &flags);
439
440 hlist_for_each_entry_safe(ri, tmp, &empty_rp, hlist) {
441 hlist_del(&ri->hlist);
442 kfree(ri);
443 }
444
445
446
447
448
449 return 1;
450 }
451 NOKPROBE_SYMBOL(trampoline_probe_handler);
452
453
454
455
456
457
458
459
460
461 static void resume_execution(struct kprobe *p, struct pt_regs *regs)
462 {
463 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
464 unsigned long ip = regs->psw.addr;
465 int fixup = probe_get_fixup_type(p->ainsn.insn);
466
467
468 if (p->ainsn.is_ftrace_insn) {
469 struct ftrace_insn *insn = (struct ftrace_insn *) p->addr;
470 struct ftrace_insn call_insn;
471
472 ftrace_generate_call_insn(&call_insn, (unsigned long) p->addr);
473
474
475
476
477
478
479 if (insn->disp == KPROBE_ON_FTRACE_CALL) {
480 ip += call_insn.disp * 2 - MCOUNT_INSN_SIZE;
481 regs->gprs[0] = (unsigned long)p->addr + sizeof(*insn);
482 }
483 }
484
485 if (fixup & FIXUP_PSW_NORMAL)
486 ip += (unsigned long) p->addr - (unsigned long) p->ainsn.insn;
487
488 if (fixup & FIXUP_BRANCH_NOT_TAKEN) {
489 int ilen = insn_length(p->ainsn.insn[0] >> 8);
490 if (ip - (unsigned long) p->ainsn.insn == ilen)
491 ip = (unsigned long) p->addr + ilen;
492 }
493
494 if (fixup & FIXUP_RETURN_REGISTER) {
495 int reg = (p->ainsn.insn[0] & 0xf0) >> 4;
496 regs->gprs[reg] += (unsigned long) p->addr -
497 (unsigned long) p->ainsn.insn;
498 }
499
500 disable_singlestep(kcb, regs, ip);
501 }
502 NOKPROBE_SYMBOL(resume_execution);
503
504 static int post_kprobe_handler(struct pt_regs *regs)
505 {
506 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
507 struct kprobe *p = kprobe_running();
508
509 if (!p)
510 return 0;
511
512 if (kcb->kprobe_status != KPROBE_REENTER && p->post_handler) {
513 kcb->kprobe_status = KPROBE_HIT_SSDONE;
514 p->post_handler(p, regs, 0);
515 }
516
517 resume_execution(p, regs);
518 pop_kprobe(kcb);
519 preempt_enable_no_resched();
520
521
522
523
524
525
526 if (regs->psw.mask & PSW_MASK_PER)
527 return 0;
528
529 return 1;
530 }
531 NOKPROBE_SYMBOL(post_kprobe_handler);
532
533 static int kprobe_trap_handler(struct pt_regs *regs, int trapnr)
534 {
535 struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
536 struct kprobe *p = kprobe_running();
537 const struct exception_table_entry *entry;
538
539 switch(kcb->kprobe_status) {
540 case KPROBE_HIT_SS:
541 case KPROBE_REENTER:
542
543
544
545
546
547
548
549 disable_singlestep(kcb, regs, (unsigned long) p->addr);
550 pop_kprobe(kcb);
551 preempt_enable_no_resched();
552 break;
553 case KPROBE_HIT_ACTIVE:
554 case KPROBE_HIT_SSDONE:
555
556
557
558
559
560 kprobes_inc_nmissed_count(p);
561
562
563
564
565
566
567
568
569 if (p->fault_handler && p->fault_handler(p, regs, trapnr))
570 return 1;
571
572
573
574
575
576 entry = s390_search_extables(regs->psw.addr);
577 if (entry) {
578 regs->psw.addr = extable_fixup(entry);
579 return 1;
580 }
581
582
583
584
585
586 break;
587 default:
588 break;
589 }
590 return 0;
591 }
592 NOKPROBE_SYMBOL(kprobe_trap_handler);
593
594 int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
595 {
596 int ret;
597
598 if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT))
599 local_irq_disable();
600 ret = kprobe_trap_handler(regs, trapnr);
601 if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT))
602 local_irq_restore(regs->psw.mask & ~PSW_MASK_PER);
603 return ret;
604 }
605 NOKPROBE_SYMBOL(kprobe_fault_handler);
606
607
608
609
610 int kprobe_exceptions_notify(struct notifier_block *self,
611 unsigned long val, void *data)
612 {
613 struct die_args *args = (struct die_args *) data;
614 struct pt_regs *regs = args->regs;
615 int ret = NOTIFY_DONE;
616
617 if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT))
618 local_irq_disable();
619
620 switch (val) {
621 case DIE_BPT:
622 if (kprobe_handler(regs))
623 ret = NOTIFY_STOP;
624 break;
625 case DIE_SSTEP:
626 if (post_kprobe_handler(regs))
627 ret = NOTIFY_STOP;
628 break;
629 case DIE_TRAP:
630 if (!preemptible() && kprobe_running() &&
631 kprobe_trap_handler(regs, args->trapnr))
632 ret = NOTIFY_STOP;
633 break;
634 default:
635 break;
636 }
637
638 if (regs->psw.mask & (PSW_MASK_IO | PSW_MASK_EXT))
639 local_irq_restore(regs->psw.mask & ~PSW_MASK_PER);
640
641 return ret;
642 }
643 NOKPROBE_SYMBOL(kprobe_exceptions_notify);
644
645 static struct kprobe trampoline = {
646 .addr = (kprobe_opcode_t *) &kretprobe_trampoline,
647 .pre_handler = trampoline_probe_handler
648 };
649
650 int __init arch_init_kprobes(void)
651 {
652 return register_kprobe(&trampoline);
653 }
654
655 int arch_trampoline_kprobe(struct kprobe *p)
656 {
657 return p->addr == (kprobe_opcode_t *) &kretprobe_trampoline;
658 }
659 NOKPROBE_SYMBOL(arch_trampoline_kprobe);