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