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30
31#define pr_fmt(fmt) "KGDB: " fmt
32
33#include <linux/pid_namespace.h>
34#include <linux/clocksource.h>
35#include <linux/serial_core.h>
36#include <linux/interrupt.h>
37#include <linux/spinlock.h>
38#include <linux/console.h>
39#include <linux/threads.h>
40#include <linux/uaccess.h>
41#include <linux/kernel.h>
42#include <linux/module.h>
43#include <linux/ptrace.h>
44#include <linux/string.h>
45#include <linux/delay.h>
46#include <linux/sched.h>
47#include <linux/sysrq.h>
48#include <linux/reboot.h>
49#include <linux/init.h>
50#include <linux/kgdb.h>
51#include <linux/kdb.h>
52#include <linux/nmi.h>
53#include <linux/pid.h>
54#include <linux/smp.h>
55#include <linux/mm.h>
56#include <linux/vmacache.h>
57#include <linux/rcupdate.h>
58#include <linux/irq.h>
59
60#include <asm/cacheflush.h>
61#include <asm/byteorder.h>
62#include <linux/atomic.h>
63
64#include "debug_core.h"
65
66static int kgdb_break_asap;
67
68struct debuggerinfo_struct kgdb_info[NR_CPUS];
69
70
71
72
73int kgdb_connected;
74EXPORT_SYMBOL_GPL(kgdb_connected);
75
76
77int kgdb_io_module_registered;
78
79
80static int exception_level;
81
82struct kgdb_io *dbg_io_ops;
83static DEFINE_SPINLOCK(kgdb_registration_lock);
84
85
86static int kgdbreboot;
87
88static int kgdb_con_registered;
89
90static int kgdb_use_con;
91
92bool dbg_is_early = true;
93
94int dbg_switch_cpu;
95
96
97int dbg_kdb_mode = 1;
98
99static int __init opt_kgdb_con(char *str)
100{
101 kgdb_use_con = 1;
102 return 0;
103}
104
105early_param("kgdbcon", opt_kgdb_con);
106
107module_param(kgdb_use_con, int, 0644);
108module_param(kgdbreboot, int, 0644);
109
110
111
112
113
114static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = {
115 [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED }
116};
117
118
119
120
121atomic_t kgdb_active = ATOMIC_INIT(-1);
122EXPORT_SYMBOL_GPL(kgdb_active);
123static DEFINE_RAW_SPINLOCK(dbg_master_lock);
124static DEFINE_RAW_SPINLOCK(dbg_slave_lock);
125
126
127
128
129
130static atomic_t masters_in_kgdb;
131static atomic_t slaves_in_kgdb;
132static atomic_t kgdb_break_tasklet_var;
133atomic_t kgdb_setting_breakpoint;
134
135struct task_struct *kgdb_usethread;
136struct task_struct *kgdb_contthread;
137
138int kgdb_single_step;
139static pid_t kgdb_sstep_pid;
140
141
142atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1);
143
144
145
146
147
148
149
150
151static int kgdb_do_roundup = 1;
152
153static int __init opt_nokgdbroundup(char *str)
154{
155 kgdb_do_roundup = 0;
156
157 return 0;
158}
159
160early_param("nokgdbroundup", opt_nokgdbroundup);
161
162
163
164
165
166
167
168
169
170int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
171{
172 int err;
173
174 err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
175 BREAK_INSTR_SIZE);
176 if (err)
177 return err;
178 err = probe_kernel_write((char *)bpt->bpt_addr,
179 arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE);
180 return err;
181}
182
183int __weak kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
184{
185 return probe_kernel_write((char *)bpt->bpt_addr,
186 (char *)bpt->saved_instr, BREAK_INSTR_SIZE);
187}
188
189int __weak kgdb_validate_break_address(unsigned long addr)
190{
191 struct kgdb_bkpt tmp;
192 int err;
193
194
195
196
197
198 tmp.bpt_addr = addr;
199 err = kgdb_arch_set_breakpoint(&tmp);
200 if (err)
201 return err;
202 err = kgdb_arch_remove_breakpoint(&tmp);
203 if (err)
204 pr_err("Critical breakpoint error, kernel memory destroyed at: %lx\n",
205 addr);
206 return err;
207}
208
209unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
210{
211 return instruction_pointer(regs);
212}
213
214int __weak kgdb_arch_init(void)
215{
216 return 0;
217}
218
219int __weak kgdb_skipexception(int exception, struct pt_regs *regs)
220{
221 return 0;
222}
223
224#ifdef CONFIG_SMP
225
226
227
228
229
230static DEFINE_PER_CPU(call_single_data_t, kgdb_roundup_csd);
231
232void __weak kgdb_call_nmi_hook(void *ignored)
233{
234
235
236
237
238
239
240
241
242 kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
243}
244
245void __weak kgdb_roundup_cpus(void)
246{
247 call_single_data_t *csd;
248 int this_cpu = raw_smp_processor_id();
249 int cpu;
250 int ret;
251
252 for_each_online_cpu(cpu) {
253
254 if (cpu == this_cpu)
255 continue;
256
257 csd = &per_cpu(kgdb_roundup_csd, cpu);
258
259
260
261
262
263
264
265
266
267 if (kgdb_info[cpu].rounding_up)
268 continue;
269 kgdb_info[cpu].rounding_up = true;
270
271 csd->func = kgdb_call_nmi_hook;
272 ret = smp_call_function_single_async(cpu, csd);
273 if (ret)
274 kgdb_info[cpu].rounding_up = false;
275 }
276}
277
278#endif
279
280
281
282
283
284static void kgdb_flush_swbreak_addr(unsigned long addr)
285{
286 if (!CACHE_FLUSH_IS_SAFE)
287 return;
288
289 if (current->mm) {
290 int i;
291
292 for (i = 0; i < VMACACHE_SIZE; i++) {
293 if (!current->vmacache.vmas[i])
294 continue;
295 flush_cache_range(current->vmacache.vmas[i],
296 addr, addr + BREAK_INSTR_SIZE);
297 }
298 }
299
300
301 flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
302}
303
304
305
306
307int dbg_activate_sw_breakpoints(void)
308{
309 int error;
310 int ret = 0;
311 int i;
312
313 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
314 if (kgdb_break[i].state != BP_SET)
315 continue;
316
317 error = kgdb_arch_set_breakpoint(&kgdb_break[i]);
318 if (error) {
319 ret = error;
320 pr_info("BP install failed: %lx\n",
321 kgdb_break[i].bpt_addr);
322 continue;
323 }
324
325 kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);
326 kgdb_break[i].state = BP_ACTIVE;
327 }
328 return ret;
329}
330
331int dbg_set_sw_break(unsigned long addr)
332{
333 int err = kgdb_validate_break_address(addr);
334 int breakno = -1;
335 int i;
336
337 if (err)
338 return err;
339
340 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
341 if ((kgdb_break[i].state == BP_SET) &&
342 (kgdb_break[i].bpt_addr == addr))
343 return -EEXIST;
344 }
345 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
346 if (kgdb_break[i].state == BP_REMOVED &&
347 kgdb_break[i].bpt_addr == addr) {
348 breakno = i;
349 break;
350 }
351 }
352
353 if (breakno == -1) {
354 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
355 if (kgdb_break[i].state == BP_UNDEFINED) {
356 breakno = i;
357 break;
358 }
359 }
360 }
361
362 if (breakno == -1)
363 return -E2BIG;
364
365 kgdb_break[breakno].state = BP_SET;
366 kgdb_break[breakno].type = BP_BREAKPOINT;
367 kgdb_break[breakno].bpt_addr = addr;
368
369 return 0;
370}
371
372int dbg_deactivate_sw_breakpoints(void)
373{
374 int error;
375 int ret = 0;
376 int i;
377
378 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
379 if (kgdb_break[i].state != BP_ACTIVE)
380 continue;
381 error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);
382 if (error) {
383 pr_info("BP remove failed: %lx\n",
384 kgdb_break[i].bpt_addr);
385 ret = error;
386 }
387
388 kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);
389 kgdb_break[i].state = BP_SET;
390 }
391 return ret;
392}
393
394int dbg_remove_sw_break(unsigned long addr)
395{
396 int i;
397
398 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
399 if ((kgdb_break[i].state == BP_SET) &&
400 (kgdb_break[i].bpt_addr == addr)) {
401 kgdb_break[i].state = BP_REMOVED;
402 return 0;
403 }
404 }
405 return -ENOENT;
406}
407
408int kgdb_isremovedbreak(unsigned long addr)
409{
410 int i;
411
412 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
413 if ((kgdb_break[i].state == BP_REMOVED) &&
414 (kgdb_break[i].bpt_addr == addr))
415 return 1;
416 }
417 return 0;
418}
419
420int dbg_remove_all_break(void)
421{
422 int error;
423 int i;
424
425
426 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
427 if (kgdb_break[i].state != BP_ACTIVE)
428 goto setundefined;
429 error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);
430 if (error)
431 pr_err("breakpoint remove failed: %lx\n",
432 kgdb_break[i].bpt_addr);
433setundefined:
434 kgdb_break[i].state = BP_UNDEFINED;
435 }
436
437
438 if (arch_kgdb_ops.remove_all_hw_break)
439 arch_kgdb_ops.remove_all_hw_break();
440
441 return 0;
442}
443
444
445
446
447
448
449
450
451
452
453static int kgdb_io_ready(int print_wait)
454{
455 if (!dbg_io_ops)
456 return 0;
457 if (kgdb_connected)
458 return 1;
459 if (atomic_read(&kgdb_setting_breakpoint))
460 return 1;
461 if (print_wait) {
462#ifdef CONFIG_KGDB_KDB
463 if (!dbg_kdb_mode)
464 pr_crit("waiting... or $3#33 for KDB\n");
465#else
466 pr_crit("Waiting for remote debugger\n");
467#endif
468 }
469 return 1;
470}
471
472static int kgdb_reenter_check(struct kgdb_state *ks)
473{
474 unsigned long addr;
475
476 if (atomic_read(&kgdb_active) != raw_smp_processor_id())
477 return 0;
478
479
480 exception_level++;
481 addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
482 dbg_deactivate_sw_breakpoints();
483
484
485
486
487
488
489
490 if (dbg_remove_sw_break(addr) == 0) {
491 exception_level = 0;
492 kgdb_skipexception(ks->ex_vector, ks->linux_regs);
493 dbg_activate_sw_breakpoints();
494 pr_crit("re-enter error: breakpoint removed %lx\n", addr);
495 WARN_ON_ONCE(1);
496
497 return 1;
498 }
499 dbg_remove_all_break();
500 kgdb_skipexception(ks->ex_vector, ks->linux_regs);
501
502 if (exception_level > 1) {
503 dump_stack();
504 panic("Recursive entry to debugger");
505 }
506
507 pr_crit("re-enter exception: ALL breakpoints killed\n");
508#ifdef CONFIG_KGDB_KDB
509
510 return 0;
511#endif
512 dump_stack();
513 panic("Recursive entry to debugger");
514
515 return 1;
516}
517
518static void dbg_touch_watchdogs(void)
519{
520 touch_softlockup_watchdog_sync();
521 clocksource_touch_watchdog();
522 rcu_cpu_stall_reset();
523}
524
525static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs,
526 int exception_state)
527{
528 unsigned long flags;
529 int sstep_tries = 100;
530 int error;
531 int cpu;
532 int trace_on = 0;
533 int online_cpus = num_online_cpus();
534 u64 time_left;
535
536 kgdb_info[ks->cpu].enter_kgdb++;
537 kgdb_info[ks->cpu].exception_state |= exception_state;
538
539 if (exception_state == DCPU_WANT_MASTER)
540 atomic_inc(&masters_in_kgdb);
541 else
542 atomic_inc(&slaves_in_kgdb);
543
544 if (arch_kgdb_ops.disable_hw_break)
545 arch_kgdb_ops.disable_hw_break(regs);
546
547acquirelock:
548
549
550
551
552 local_irq_save(flags);
553
554 cpu = ks->cpu;
555 kgdb_info[cpu].debuggerinfo = regs;
556 kgdb_info[cpu].task = current;
557 kgdb_info[cpu].ret_state = 0;
558 kgdb_info[cpu].irq_depth = hardirq_count() >> HARDIRQ_SHIFT;
559
560
561 smp_mb();
562
563 if (exception_level == 1) {
564 if (raw_spin_trylock(&dbg_master_lock))
565 atomic_xchg(&kgdb_active, cpu);
566 goto cpu_master_loop;
567 }
568
569
570
571
572
573 while (1) {
574cpu_loop:
575 if (kgdb_info[cpu].exception_state & DCPU_NEXT_MASTER) {
576 kgdb_info[cpu].exception_state &= ~DCPU_NEXT_MASTER;
577 goto cpu_master_loop;
578 } else if (kgdb_info[cpu].exception_state & DCPU_WANT_MASTER) {
579 if (raw_spin_trylock(&dbg_master_lock)) {
580 atomic_xchg(&kgdb_active, cpu);
581 break;
582 }
583 } else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) {
584 if (!raw_spin_is_locked(&dbg_slave_lock))
585 goto return_normal;
586 } else {
587return_normal:
588
589
590
591 if (arch_kgdb_ops.correct_hw_break)
592 arch_kgdb_ops.correct_hw_break();
593 if (trace_on)
594 tracing_on();
595 kgdb_info[cpu].debuggerinfo = NULL;
596 kgdb_info[cpu].task = NULL;
597 kgdb_info[cpu].exception_state &=
598 ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE);
599 kgdb_info[cpu].enter_kgdb--;
600 smp_mb__before_atomic();
601 atomic_dec(&slaves_in_kgdb);
602 dbg_touch_watchdogs();
603 local_irq_restore(flags);
604 return 0;
605 }
606 cpu_relax();
607 }
608
609
610
611
612
613
614
615 if (atomic_read(&kgdb_cpu_doing_single_step) != -1 &&
616 (kgdb_info[cpu].task &&
617 kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) {
618 atomic_set(&kgdb_active, -1);
619 raw_spin_unlock(&dbg_master_lock);
620 dbg_touch_watchdogs();
621 local_irq_restore(flags);
622
623 goto acquirelock;
624 }
625
626 if (!kgdb_io_ready(1)) {
627 kgdb_info[cpu].ret_state = 1;
628 goto kgdb_restore;
629 }
630
631
632
633
634 if (kgdb_skipexception(ks->ex_vector, ks->linux_regs))
635 goto kgdb_restore;
636
637
638 if (dbg_io_ops->pre_exception)
639 dbg_io_ops->pre_exception();
640
641
642
643
644
645 if (!kgdb_single_step)
646 raw_spin_lock(&dbg_slave_lock);
647
648#ifdef CONFIG_SMP
649
650 if (ks->send_ready)
651 atomic_set(ks->send_ready, 1);
652
653
654 else if ((!kgdb_single_step) && kgdb_do_roundup)
655 kgdb_roundup_cpus();
656#endif
657
658
659
660
661 time_left = MSEC_PER_SEC;
662 while (kgdb_do_roundup && --time_left &&
663 (atomic_read(&masters_in_kgdb) + atomic_read(&slaves_in_kgdb)) !=
664 online_cpus)
665 udelay(1000);
666 if (!time_left)
667 pr_crit("Timed out waiting for secondary CPUs.\n");
668
669
670
671
672
673 dbg_deactivate_sw_breakpoints();
674 kgdb_single_step = 0;
675 kgdb_contthread = current;
676 exception_level = 0;
677 trace_on = tracing_is_on();
678 if (trace_on)
679 tracing_off();
680
681 while (1) {
682cpu_master_loop:
683 if (dbg_kdb_mode) {
684 kgdb_connected = 1;
685 error = kdb_stub(ks);
686 if (error == -1)
687 continue;
688 kgdb_connected = 0;
689 } else {
690 error = gdb_serial_stub(ks);
691 }
692
693 if (error == DBG_PASS_EVENT) {
694 dbg_kdb_mode = !dbg_kdb_mode;
695 } else if (error == DBG_SWITCH_CPU_EVENT) {
696 kgdb_info[dbg_switch_cpu].exception_state |=
697 DCPU_NEXT_MASTER;
698 goto cpu_loop;
699 } else {
700 kgdb_info[cpu].ret_state = error;
701 break;
702 }
703 }
704
705
706 if (dbg_io_ops->post_exception)
707 dbg_io_ops->post_exception();
708
709 if (!kgdb_single_step) {
710 raw_spin_unlock(&dbg_slave_lock);
711
712 while (kgdb_do_roundup && atomic_read(&slaves_in_kgdb))
713 cpu_relax();
714 }
715
716kgdb_restore:
717 if (atomic_read(&kgdb_cpu_doing_single_step) != -1) {
718 int sstep_cpu = atomic_read(&kgdb_cpu_doing_single_step);
719 if (kgdb_info[sstep_cpu].task)
720 kgdb_sstep_pid = kgdb_info[sstep_cpu].task->pid;
721 else
722 kgdb_sstep_pid = 0;
723 }
724 if (arch_kgdb_ops.correct_hw_break)
725 arch_kgdb_ops.correct_hw_break();
726 if (trace_on)
727 tracing_on();
728
729 kgdb_info[cpu].debuggerinfo = NULL;
730 kgdb_info[cpu].task = NULL;
731 kgdb_info[cpu].exception_state &=
732 ~(DCPU_WANT_MASTER | DCPU_IS_SLAVE);
733 kgdb_info[cpu].enter_kgdb--;
734 smp_mb__before_atomic();
735 atomic_dec(&masters_in_kgdb);
736
737 atomic_set(&kgdb_active, -1);
738 raw_spin_unlock(&dbg_master_lock);
739 dbg_touch_watchdogs();
740 local_irq_restore(flags);
741
742 return kgdb_info[cpu].ret_state;
743}
744
745
746
747
748
749
750
751
752int
753kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
754{
755 struct kgdb_state kgdb_var;
756 struct kgdb_state *ks = &kgdb_var;
757 int ret = 0;
758
759 if (arch_kgdb_ops.enable_nmi)
760 arch_kgdb_ops.enable_nmi(0);
761
762
763
764
765
766
767 if (signo != SIGTRAP && panic_timeout)
768 return 1;
769
770 memset(ks, 0, sizeof(struct kgdb_state));
771 ks->cpu = raw_smp_processor_id();
772 ks->ex_vector = evector;
773 ks->signo = signo;
774 ks->err_code = ecode;
775 ks->linux_regs = regs;
776
777 if (kgdb_reenter_check(ks))
778 goto out;
779 if (kgdb_info[ks->cpu].enter_kgdb != 0)
780 goto out;
781
782 ret = kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER);
783out:
784 if (arch_kgdb_ops.enable_nmi)
785 arch_kgdb_ops.enable_nmi(1);
786 return ret;
787}
788
789
790
791
792
793
794
795static int module_event(struct notifier_block *self, unsigned long val,
796 void *data)
797{
798 return 0;
799}
800
801static struct notifier_block dbg_module_load_nb = {
802 .notifier_call = module_event,
803};
804
805int kgdb_nmicallback(int cpu, void *regs)
806{
807#ifdef CONFIG_SMP
808 struct kgdb_state kgdb_var;
809 struct kgdb_state *ks = &kgdb_var;
810
811 kgdb_info[cpu].rounding_up = false;
812
813 memset(ks, 0, sizeof(struct kgdb_state));
814 ks->cpu = cpu;
815 ks->linux_regs = regs;
816
817 if (kgdb_info[ks->cpu].enter_kgdb == 0 &&
818 raw_spin_is_locked(&dbg_master_lock)) {
819 kgdb_cpu_enter(ks, regs, DCPU_IS_SLAVE);
820 return 0;
821 }
822#endif
823 return 1;
824}
825
826int kgdb_nmicallin(int cpu, int trapnr, void *regs, int err_code,
827 atomic_t *send_ready)
828{
829#ifdef CONFIG_SMP
830 if (!kgdb_io_ready(0) || !send_ready)
831 return 1;
832
833 if (kgdb_info[cpu].enter_kgdb == 0) {
834 struct kgdb_state kgdb_var;
835 struct kgdb_state *ks = &kgdb_var;
836
837 memset(ks, 0, sizeof(struct kgdb_state));
838 ks->cpu = cpu;
839 ks->ex_vector = trapnr;
840 ks->signo = SIGTRAP;
841 ks->err_code = err_code;
842 ks->linux_regs = regs;
843 ks->send_ready = send_ready;
844 kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER);
845 return 0;
846 }
847#endif
848 return 1;
849}
850
851static void kgdb_console_write(struct console *co, const char *s,
852 unsigned count)
853{
854 unsigned long flags;
855
856
857
858 if (!kgdb_connected || atomic_read(&kgdb_active) != -1 || dbg_kdb_mode)
859 return;
860
861 local_irq_save(flags);
862 gdbstub_msg_write(s, count);
863 local_irq_restore(flags);
864}
865
866static struct console kgdbcons = {
867 .name = "kgdb",
868 .write = kgdb_console_write,
869 .flags = CON_PRINTBUFFER | CON_ENABLED,
870 .index = -1,
871};
872
873#ifdef CONFIG_MAGIC_SYSRQ
874static void sysrq_handle_dbg(int key)
875{
876 if (!dbg_io_ops) {
877 pr_crit("ERROR: No KGDB I/O module available\n");
878 return;
879 }
880 if (!kgdb_connected) {
881#ifdef CONFIG_KGDB_KDB
882 if (!dbg_kdb_mode)
883 pr_crit("KGDB or $3#33 for KDB\n");
884#else
885 pr_crit("Entering KGDB\n");
886#endif
887 }
888
889 kgdb_breakpoint();
890}
891
892static struct sysrq_key_op sysrq_dbg_op = {
893 .handler = sysrq_handle_dbg,
894 .help_msg = "debug(g)",
895 .action_msg = "DEBUG",
896};
897#endif
898
899static int kgdb_panic_event(struct notifier_block *self,
900 unsigned long val,
901 void *data)
902{
903
904
905
906
907
908
909 if (panic_timeout)
910 return NOTIFY_DONE;
911
912 if (dbg_kdb_mode)
913 kdb_printf("PANIC: %s\n", (char *)data);
914 kgdb_breakpoint();
915 return NOTIFY_DONE;
916}
917
918static struct notifier_block kgdb_panic_event_nb = {
919 .notifier_call = kgdb_panic_event,
920 .priority = INT_MAX,
921};
922
923void __weak kgdb_arch_late(void)
924{
925}
926
927void __init dbg_late_init(void)
928{
929 dbg_is_early = false;
930 if (kgdb_io_module_registered)
931 kgdb_arch_late();
932 kdb_init(KDB_INIT_FULL);
933}
934
935static int
936dbg_notify_reboot(struct notifier_block *this, unsigned long code, void *x)
937{
938
939
940
941
942
943
944 switch (kgdbreboot) {
945 case 1:
946 kgdb_breakpoint();
947 case -1:
948 goto done;
949 }
950 if (!dbg_kdb_mode)
951 gdbstub_exit(code);
952done:
953 return NOTIFY_DONE;
954}
955
956static struct notifier_block dbg_reboot_notifier = {
957 .notifier_call = dbg_notify_reboot,
958 .next = NULL,
959 .priority = INT_MAX,
960};
961
962static void kgdb_register_callbacks(void)
963{
964 if (!kgdb_io_module_registered) {
965 kgdb_io_module_registered = 1;
966 kgdb_arch_init();
967 if (!dbg_is_early)
968 kgdb_arch_late();
969 register_module_notifier(&dbg_module_load_nb);
970 register_reboot_notifier(&dbg_reboot_notifier);
971 atomic_notifier_chain_register(&panic_notifier_list,
972 &kgdb_panic_event_nb);
973#ifdef CONFIG_MAGIC_SYSRQ
974 register_sysrq_key('g', &sysrq_dbg_op);
975#endif
976 if (kgdb_use_con && !kgdb_con_registered) {
977 register_console(&kgdbcons);
978 kgdb_con_registered = 1;
979 }
980 }
981}
982
983static void kgdb_unregister_callbacks(void)
984{
985
986
987
988
989
990 if (kgdb_io_module_registered) {
991 kgdb_io_module_registered = 0;
992 unregister_reboot_notifier(&dbg_reboot_notifier);
993 unregister_module_notifier(&dbg_module_load_nb);
994 atomic_notifier_chain_unregister(&panic_notifier_list,
995 &kgdb_panic_event_nb);
996 kgdb_arch_exit();
997#ifdef CONFIG_MAGIC_SYSRQ
998 unregister_sysrq_key('g', &sysrq_dbg_op);
999#endif
1000 if (kgdb_con_registered) {
1001 unregister_console(&kgdbcons);
1002 kgdb_con_registered = 0;
1003 }
1004 }
1005}
1006
1007
1008
1009
1010
1011
1012
1013static void kgdb_tasklet_bpt(unsigned long ing)
1014{
1015 kgdb_breakpoint();
1016 atomic_set(&kgdb_break_tasklet_var, 0);
1017}
1018
1019static DECLARE_TASKLET(kgdb_tasklet_breakpoint, kgdb_tasklet_bpt, 0);
1020
1021void kgdb_schedule_breakpoint(void)
1022{
1023 if (atomic_read(&kgdb_break_tasklet_var) ||
1024 atomic_read(&kgdb_active) != -1 ||
1025 atomic_read(&kgdb_setting_breakpoint))
1026 return;
1027 atomic_inc(&kgdb_break_tasklet_var);
1028 tasklet_schedule(&kgdb_tasklet_breakpoint);
1029}
1030EXPORT_SYMBOL_GPL(kgdb_schedule_breakpoint);
1031
1032static void kgdb_initial_breakpoint(void)
1033{
1034 kgdb_break_asap = 0;
1035
1036 pr_crit("Waiting for connection from remote gdb...\n");
1037 kgdb_breakpoint();
1038}
1039
1040
1041
1042
1043
1044
1045
1046int kgdb_register_io_module(struct kgdb_io *new_dbg_io_ops)
1047{
1048 int err;
1049
1050 spin_lock(&kgdb_registration_lock);
1051
1052 if (dbg_io_ops) {
1053 spin_unlock(&kgdb_registration_lock);
1054
1055 pr_err("Another I/O driver is already registered with KGDB\n");
1056 return -EBUSY;
1057 }
1058
1059 if (new_dbg_io_ops->init) {
1060 err = new_dbg_io_ops->init();
1061 if (err) {
1062 spin_unlock(&kgdb_registration_lock);
1063 return err;
1064 }
1065 }
1066
1067 dbg_io_ops = new_dbg_io_ops;
1068
1069 spin_unlock(&kgdb_registration_lock);
1070
1071 pr_info("Registered I/O driver %s\n", new_dbg_io_ops->name);
1072
1073
1074 kgdb_register_callbacks();
1075
1076 if (kgdb_break_asap)
1077 kgdb_initial_breakpoint();
1078
1079 return 0;
1080}
1081EXPORT_SYMBOL_GPL(kgdb_register_io_module);
1082
1083
1084
1085
1086
1087
1088
1089void kgdb_unregister_io_module(struct kgdb_io *old_dbg_io_ops)
1090{
1091 BUG_ON(kgdb_connected);
1092
1093
1094
1095
1096
1097 kgdb_unregister_callbacks();
1098
1099 spin_lock(&kgdb_registration_lock);
1100
1101 WARN_ON_ONCE(dbg_io_ops != old_dbg_io_ops);
1102 dbg_io_ops = NULL;
1103
1104 spin_unlock(&kgdb_registration_lock);
1105
1106 pr_info("Unregistered I/O driver %s, debugger disabled\n",
1107 old_dbg_io_ops->name);
1108}
1109EXPORT_SYMBOL_GPL(kgdb_unregister_io_module);
1110
1111int dbg_io_get_char(void)
1112{
1113 int ret = dbg_io_ops->read_char();
1114 if (ret == NO_POLL_CHAR)
1115 return -1;
1116 if (!dbg_kdb_mode)
1117 return ret;
1118 if (ret == 127)
1119 return 8;
1120 return ret;
1121}
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131noinline void kgdb_breakpoint(void)
1132{
1133 atomic_inc(&kgdb_setting_breakpoint);
1134 wmb();
1135 arch_kgdb_breakpoint();
1136 wmb();
1137 atomic_dec(&kgdb_setting_breakpoint);
1138}
1139EXPORT_SYMBOL_GPL(kgdb_breakpoint);
1140
1141static int __init opt_kgdb_wait(char *str)
1142{
1143 kgdb_break_asap = 1;
1144
1145 kdb_init(KDB_INIT_EARLY);
1146 if (kgdb_io_module_registered)
1147 kgdb_initial_breakpoint();
1148
1149 return 0;
1150}
1151
1152early_param("kgdbwait", opt_kgdb_wait);
1153