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diff --git a/kernel/kgdb.c b/kernel/kgdb.c
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1/*
2 * KGDB stub.
3 *
4 * Maintainer: Jason Wessel <jason.wessel@windriver.com>
5 *
6 * Copyright (C) 2000-2001 VERITAS Software Corporation.
7 * Copyright (C) 2002-2004 Timesys Corporation
8 * Copyright (C) 2003-2004 Amit S. Kale <amitkale@linsyssoft.com>
9 * Copyright (C) 2004 Pavel Machek <pavel@suse.cz>
10 * Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org>
11 * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd.
12 * Copyright (C) 2005-2008 Wind River Systems, Inc.
13 * Copyright (C) 2007 MontaVista Software, Inc.
14 * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
15 *
16 * Contributors at various stages not listed above:
17 * Jason Wessel ( jason.wessel@windriver.com )
18 * George Anzinger <george@mvista.com>
19 * Anurekh Saxena (anurekh.saxena@timesys.com)
20 * Lake Stevens Instrument Division (Glenn Engel)
21 * Jim Kingdon, Cygnus Support.
22 *
23 * Original KGDB stub: David Grothe <dave@gcom.com>,
24 * Tigran Aivazian <tigran@sco.com>
25 *
26 * This file is licensed under the terms of the GNU General Public License
27 * version 2. This program is licensed "as is" without any warranty of any
28 * kind, whether express or implied.
29 */
30#include <linux/pid_namespace.h>
31#include <linux/clocksource.h>
32#include <linux/interrupt.h>
33#include <linux/spinlock.h>
34#include <linux/console.h>
35#include <linux/threads.h>
36#include <linux/uaccess.h>
37#include <linux/kernel.h>
38#include <linux/module.h>
39#include <linux/ptrace.h>
40#include <linux/reboot.h>
41#include <linux/string.h>
42#include <linux/delay.h>
43#include <linux/sched.h>
44#include <linux/sysrq.h>
45#include <linux/init.h>
46#include <linux/kgdb.h>
47#include <linux/pid.h>
48#include <linux/smp.h>
49#include <linux/mm.h>
50
51#include <asm/cacheflush.h>
52#include <asm/byteorder.h>
53#include <asm/atomic.h>
54#include <asm/system.h>
55
56static int kgdb_break_asap;
57
58struct kgdb_state {
59 int ex_vector;
60 int signo;
61 int err_code;
62 int cpu;
63 int pass_exception;
64 long threadid;
65 long kgdb_usethreadid;
66 struct pt_regs *linux_regs;
67};
68
69static struct debuggerinfo_struct {
70 void *debuggerinfo;
71 struct task_struct *task;
72} kgdb_info[NR_CPUS];
73
74/**
75 * kgdb_connected - Is a host GDB connected to us?
76 */
77int kgdb_connected;
78EXPORT_SYMBOL_GPL(kgdb_connected);
79
80/* All the KGDB handlers are installed */
81static int kgdb_io_module_registered;
82
83/* Guard for recursive entry */
84static int exception_level;
85
86static struct kgdb_io *kgdb_io_ops;
87static DEFINE_SPINLOCK(kgdb_registration_lock);
88
89/* kgdb console driver is loaded */
90static int kgdb_con_registered;
91/* determine if kgdb console output should be used */
92static int kgdb_use_con;
93
94static int __init opt_kgdb_con(char *str)
95{
96 kgdb_use_con = 1;
97 return 0;
98}
99
100early_param("kgdbcon", opt_kgdb_con);
101
102module_param(kgdb_use_con, int, 0644);
103
104/*
105 * Holds information about breakpoints in a kernel. These breakpoints are
106 * added and removed by gdb.
107 */
108static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = {
109 [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED }
110};
111
112/*
113 * The CPU# of the active CPU, or -1 if none:
114 */
115atomic_t kgdb_active = ATOMIC_INIT(-1);
116
117/*
118 * We use NR_CPUs not PERCPU, in case kgdb is used to debug early
119 * bootup code (which might not have percpu set up yet):
120 */
121static atomic_t passive_cpu_wait[NR_CPUS];
122static atomic_t cpu_in_kgdb[NR_CPUS];
123atomic_t kgdb_setting_breakpoint;
124
125struct task_struct *kgdb_usethread;
126struct task_struct *kgdb_contthread;
127
128int kgdb_single_step;
129
130/* Our I/O buffers. */
131static char remcom_in_buffer[BUFMAX];
132static char remcom_out_buffer[BUFMAX];
133
134/* Storage for the registers, in GDB format. */
135static unsigned long gdb_regs[(NUMREGBYTES +
136 sizeof(unsigned long) - 1) /
137 sizeof(unsigned long)];
138
139/* to keep track of the CPU which is doing the single stepping*/
140atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1);
141
142/*
143 * If you are debugging a problem where roundup (the collection of
144 * all other CPUs) is a problem [this should be extremely rare],
145 * then use the nokgdbroundup option to avoid roundup. In that case
146 * the other CPUs might interfere with your debugging context, so
147 * use this with care:
148 */
149int kgdb_do_roundup = 1;
150
151static int __init opt_nokgdbroundup(char *str)
152{
153 kgdb_do_roundup = 0;
154
155 return 0;
156}
157
158early_param("nokgdbroundup", opt_nokgdbroundup);
159
160/*
161 * Finally, some KGDB code :-)
162 */
163
164/*
165 * Weak aliases for breakpoint management,
166 * can be overriden by architectures when needed:
167 */
168int __weak kgdb_validate_break_address(unsigned long addr)
169{
170 char tmp_variable[BREAK_INSTR_SIZE];
171
172 return probe_kernel_read(tmp_variable, (char *)addr, BREAK_INSTR_SIZE);
173}
174
175int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
176{
177 int err;
178
179 err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE);
180 if (err)
181 return err;
182
183 return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr,
184 BREAK_INSTR_SIZE);
185}
186
187int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle)
188{
189 return probe_kernel_write((char *)addr,
190 (char *)bundle, BREAK_INSTR_SIZE);
191}
192
193unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
194{
195 return instruction_pointer(regs);
196}
197
198int __weak kgdb_arch_init(void)
199{
200 return 0;
201}
202
203int __weak kgdb_skipexception(int exception, struct pt_regs *regs)
204{
205 return 0;
206}
207
208void __weak
209kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code)
210{
211 return;
212}
213
214/**
215 * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
216 * @regs: Current &struct pt_regs.
217 *
218 * This function will be called if the particular architecture must
219 * disable hardware debugging while it is processing gdb packets or
220 * handling exception.
221 */
222void __weak kgdb_disable_hw_debug(struct pt_regs *regs)
223{
224}
225
226/*
227 * GDB remote protocol parser:
228 */
229
230static const char hexchars[] = "0123456789abcdef";
231
232static int hex(char ch)
233{
234 if ((ch >= 'a') && (ch <= 'f'))
235 return ch - 'a' + 10;
236 if ((ch >= '0') && (ch <= '9'))
237 return ch - '0';
238 if ((ch >= 'A') && (ch <= 'F'))
239 return ch - 'A' + 10;
240 return -1;
241}
242
243/* scan for the sequence $<data>#<checksum> */
244static void get_packet(char *buffer)
245{
246 unsigned char checksum;
247 unsigned char xmitcsum;
248 int count;
249 char ch;
250
251 do {
252 /*
253 * Spin and wait around for the start character, ignore all
254 * other characters:
255 */
256 while ((ch = (kgdb_io_ops->read_char())) != '$')
257 /* nothing */;
258
259 kgdb_connected = 1;
260 checksum = 0;
261 xmitcsum = -1;
262
263 count = 0;
264
265 /*
266 * now, read until a # or end of buffer is found:
267 */
268 while (count < (BUFMAX - 1)) {
269 ch = kgdb_io_ops->read_char();
270 if (ch == '#')
271 break;
272 checksum = checksum + ch;
273 buffer[count] = ch;
274 count = count + 1;
275 }
276 buffer[count] = 0;
277
278 if (ch == '#') {
279 xmitcsum = hex(kgdb_io_ops->read_char()) << 4;
280 xmitcsum += hex(kgdb_io_ops->read_char());
281
282 if (checksum != xmitcsum)
283 /* failed checksum */
284 kgdb_io_ops->write_char('-');
285 else
286 /* successful transfer */
287 kgdb_io_ops->write_char('+');
288 if (kgdb_io_ops->flush)
289 kgdb_io_ops->flush();
290 }
291 } while (checksum != xmitcsum);
292}
293
294/*
295 * Send the packet in buffer.
296 * Check for gdb connection if asked for.
297 */
298static void put_packet(char *buffer)
299{
300 unsigned char checksum;
301 int count;
302 char ch;
303
304 /*
305 * $<packet info>#<checksum>.
306 */
307 while (1) {
308 kgdb_io_ops->write_char('$');
309 checksum = 0;
310 count = 0;
311
312 while ((ch = buffer[count])) {
313 kgdb_io_ops->write_char(ch);
314 checksum += ch;
315 count++;
316 }
317
318 kgdb_io_ops->write_char('#');
319 kgdb_io_ops->write_char(hexchars[checksum >> 4]);
320 kgdb_io_ops->write_char(hexchars[checksum & 0xf]);
321 if (kgdb_io_ops->flush)
322 kgdb_io_ops->flush();
323
324 /* Now see what we get in reply. */
325 ch = kgdb_io_ops->read_char();
326
327 if (ch == 3)
328 ch = kgdb_io_ops->read_char();
329
330 /* If we get an ACK, we are done. */
331 if (ch == '+')
332 return;
333
334 /*
335 * If we get the start of another packet, this means
336 * that GDB is attempting to reconnect. We will NAK
337 * the packet being sent, and stop trying to send this
338 * packet.
339 */
340 if (ch == '$') {
341 kgdb_io_ops->write_char('-');
342 if (kgdb_io_ops->flush)
343 kgdb_io_ops->flush();
344 return;
345 }
346 }
347}
348
349static char *pack_hex_byte(char *pkt, u8 byte)
350{
351 *pkt++ = hexchars[byte >> 4];
352 *pkt++ = hexchars[byte & 0xf];
353
354 return pkt;
355}
356
357/*
358 * Convert the memory pointed to by mem into hex, placing result in buf.
359 * Return a pointer to the last char put in buf (null). May return an error.
360 */
361int kgdb_mem2hex(char *mem, char *buf, int count)
362{
363 char *tmp;
364 int err;
365
366 /*
367 * We use the upper half of buf as an intermediate buffer for the
368 * raw memory copy. Hex conversion will work against this one.
369 */
370 tmp = buf + count;
371
372 err = probe_kernel_read(tmp, mem, count);
373 if (!err) {
374 while (count > 0) {
375 buf = pack_hex_byte(buf, *tmp);
376 tmp++;
377 count--;
378 }
379
380 *buf = 0;
381 }
382
383 return err;
384}
385
386/*
387 * Copy the binary array pointed to by buf into mem. Fix $, #, and
388 * 0x7d escaped with 0x7d. Return a pointer to the character after
389 * the last byte written.
390 */
391static int kgdb_ebin2mem(char *buf, char *mem, int count)
392{
393 int err = 0;
394 char c;
395
396 while (count-- > 0) {
397 c = *buf++;
398 if (c == 0x7d)
399 c = *buf++ ^ 0x20;
400
401 err = probe_kernel_write(mem, &c, 1);
402 if (err)
403 break;
404
405 mem++;
406 }
407
408 return err;
409}
410
411/*
412 * Convert the hex array pointed to by buf into binary to be placed in mem.
413 * Return a pointer to the character AFTER the last byte written.
414 * May return an error.
415 */
416int kgdb_hex2mem(char *buf, char *mem, int count)
417{
418 char *tmp_raw;
419 char *tmp_hex;
420
421 /*
422 * We use the upper half of buf as an intermediate buffer for the
423 * raw memory that is converted from hex.
424 */
425 tmp_raw = buf + count * 2;
426
427 tmp_hex = tmp_raw - 1;
428 while (tmp_hex >= buf) {
429 tmp_raw--;
430 *tmp_raw = hex(*tmp_hex--);
431 *tmp_raw |= hex(*tmp_hex--) << 4;
432 }
433
434 return probe_kernel_write(mem, tmp_raw, count);
435}
436
437/*
438 * While we find nice hex chars, build a long_val.
439 * Return number of chars processed.
440 */
441int kgdb_hex2long(char **ptr, long *long_val)
442{
443 int hex_val;
444 int num = 0;
445
446 *long_val = 0;
447
448 while (**ptr) {
449 hex_val = hex(**ptr);
450 if (hex_val < 0)
451 break;
452
453 *long_val = (*long_val << 4) | hex_val;
454 num++;
455 (*ptr)++;
456 }
457
458 return num;
459}
460
461/* Write memory due to an 'M' or 'X' packet. */
462static int write_mem_msg(int binary)
463{
464 char *ptr = &remcom_in_buffer[1];
465 unsigned long addr;
466 unsigned long length;
467 int err;
468
469 if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
470 kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
471 if (binary)
472 err = kgdb_ebin2mem(ptr, (char *)addr, length);
473 else
474 err = kgdb_hex2mem(ptr, (char *)addr, length);
475 if (err)
476 return err;
477 if (CACHE_FLUSH_IS_SAFE)
478 flush_icache_range(addr, addr + length + 1);
479 return 0;
480 }
481
482 return -EINVAL;
483}
484
485static void error_packet(char *pkt, int error)
486{
487 error = -error;
488 pkt[0] = 'E';
489 pkt[1] = hexchars[(error / 10)];
490 pkt[2] = hexchars[(error % 10)];
491 pkt[3] = '\0';
492}
493
494/*
495 * Thread ID accessors. We represent a flat TID space to GDB, where
496 * the per CPU idle threads (which under Linux all have PID 0) are
497 * remapped to negative TIDs.
498 */
499
500#define BUF_THREAD_ID_SIZE 16
501
502static char *pack_threadid(char *pkt, unsigned char *id)
503{
504 char *limit;
505
506 limit = pkt + BUF_THREAD_ID_SIZE;
507 while (pkt < limit)
508 pkt = pack_hex_byte(pkt, *id++);
509
510 return pkt;
511}
512
513static void int_to_threadref(unsigned char *id, int value)
514{
515 unsigned char *scan;
516 int i = 4;
517
518 scan = (unsigned char *)id;
519 while (i--)
520 *scan++ = 0;
521 *scan++ = (value >> 24) & 0xff;
522 *scan++ = (value >> 16) & 0xff;
523 *scan++ = (value >> 8) & 0xff;
524 *scan++ = (value & 0xff);
525}
526
527static struct task_struct *getthread(struct pt_regs *regs, int tid)
528{
529 /*
530 * Non-positive TIDs are remapped idle tasks:
531 */
532 if (tid <= 0)
533 return idle_task(-tid);
534
535 /*
536 * find_task_by_pid_ns() does not take the tasklist lock anymore
537 * but is nicely RCU locked - hence is a pretty resilient
538 * thing to use:
539 */
540 return find_task_by_pid_ns(tid, &init_pid_ns);
541}
542
543/*
544 * CPU debug state control:
545 */
546
547#ifdef CONFIG_SMP
548static void kgdb_wait(struct pt_regs *regs)
549{
550 unsigned long flags;
551 int cpu;
552
553 local_irq_save(flags);
554 cpu = raw_smp_processor_id();
555 kgdb_info[cpu].debuggerinfo = regs;
556 kgdb_info[cpu].task = current;
557 /*
558 * Make sure the above info reaches the primary CPU before
559 * our cpu_in_kgdb[] flag setting does:
560 */
561 smp_wmb();
562 atomic_set(&cpu_in_kgdb[cpu], 1);
563
564 /* Wait till primary CPU is done with debugging */
565 while (atomic_read(&passive_cpu_wait[cpu]))
566 cpu_relax();
567
568 kgdb_info[cpu].debuggerinfo = NULL;
569 kgdb_info[cpu].task = NULL;
570
571 /* fix up hardware debug registers on local cpu */
572 if (arch_kgdb_ops.correct_hw_break)
573 arch_kgdb_ops.correct_hw_break();
574
575 /* Signal the primary CPU that we are done: */
576 atomic_set(&cpu_in_kgdb[cpu], 0);
577 clocksource_touch_watchdog();
578 local_irq_restore(flags);
579}
580#endif
581
582/*
583 * Some architectures need cache flushes when we set/clear a
584 * breakpoint:
585 */
586static void kgdb_flush_swbreak_addr(unsigned long addr)
587{
588 if (!CACHE_FLUSH_IS_SAFE)
589 return;
590
591 if (current->mm && current->mm->mmap_cache) {
592 flush_cache_range(current->mm->mmap_cache,
593 addr, addr + BREAK_INSTR_SIZE);
594 }
595 /* Force flush instruction cache if it was outside the mm */
596 flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
597}
598
599/*
600 * SW breakpoint management:
601 */
602static int kgdb_activate_sw_breakpoints(void)
603{
604 unsigned long addr;
605 int error = 0;
606 int i;
607
608 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
609 if (kgdb_break[i].state != BP_SET)
610 continue;
611
612 addr = kgdb_break[i].bpt_addr;
613 error = kgdb_arch_set_breakpoint(addr,
614 kgdb_break[i].saved_instr);
615 if (error)
616 return error;
617
618 kgdb_flush_swbreak_addr(addr);
619 kgdb_break[i].state = BP_ACTIVE;
620 }
621 return 0;
622}
623
624static int kgdb_set_sw_break(unsigned long addr)
625{
626 int err = kgdb_validate_break_address(addr);
627 int breakno = -1;
628 int i;
629
630 if (err)
631 return err;
632
633 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
634 if ((kgdb_break[i].state == BP_SET) &&
635 (kgdb_break[i].bpt_addr == addr))
636 return -EEXIST;
637 }
638 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
639 if (kgdb_break[i].state == BP_REMOVED &&
640 kgdb_break[i].bpt_addr == addr) {
641 breakno = i;
642 break;
643 }
644 }
645
646 if (breakno == -1) {
647 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
648 if (kgdb_break[i].state == BP_UNDEFINED) {
649 breakno = i;
650 break;
651 }
652 }
653 }
654
655 if (breakno == -1)
656 return -E2BIG;
657
658 kgdb_break[breakno].state = BP_SET;
659 kgdb_break[breakno].type = BP_BREAKPOINT;
660 kgdb_break[breakno].bpt_addr = addr;
661
662 return 0;
663}
664
665static int kgdb_deactivate_sw_breakpoints(void)
666{
667 unsigned long addr;
668 int error = 0;
669 int i;
670
671 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
672 if (kgdb_break[i].state != BP_ACTIVE)
673 continue;
674 addr = kgdb_break[i].bpt_addr;
675 error = kgdb_arch_remove_breakpoint(addr,
676 kgdb_break[i].saved_instr);
677 if (error)
678 return error;
679
680 kgdb_flush_swbreak_addr(addr);
681 kgdb_break[i].state = BP_SET;
682 }
683 return 0;
684}
685
686static int kgdb_remove_sw_break(unsigned long addr)
687{
688 int i;
689
690 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
691 if ((kgdb_break[i].state == BP_SET) &&
692 (kgdb_break[i].bpt_addr == addr)) {
693 kgdb_break[i].state = BP_REMOVED;
694 return 0;
695 }
696 }
697 return -ENOENT;
698}
699
700int kgdb_isremovedbreak(unsigned long addr)
701{
702 int i;
703
704 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
705 if ((kgdb_break[i].state == BP_REMOVED) &&
706 (kgdb_break[i].bpt_addr == addr))
707 return 1;
708 }
709 return 0;
710}
711
712int remove_all_break(void)
713{
714 unsigned long addr;
715 int error;
716 int i;
717
718 /* Clear memory breakpoints. */
719 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
720 if (kgdb_break[i].state != BP_ACTIVE)
721 goto setundefined;
722 addr = kgdb_break[i].bpt_addr;
723 error = kgdb_arch_remove_breakpoint(addr,
724 kgdb_break[i].saved_instr);
725 if (error)
726 printk(KERN_ERR "KGDB: breakpoint remove failed: %lx\n",
727 addr);
728setundefined:
729 kgdb_break[i].state = BP_UNDEFINED;
730 }
731
732 /* Clear hardware breakpoints. */
733 if (arch_kgdb_ops.remove_all_hw_break)
734 arch_kgdb_ops.remove_all_hw_break();
735
736 return 0;
737}
738
739/*
740 * Remap normal tasks to their real PID, idle tasks to -1 ... -NR_CPUs:
741 */
742static inline int shadow_pid(int realpid)
743{
744 if (realpid)
745 return realpid;
746
747 return -1-raw_smp_processor_id();
748}
749
750static char gdbmsgbuf[BUFMAX + 1];
751
752static void kgdb_msg_write(const char *s, int len)
753{
754 char *bufptr;
755 int wcount;
756 int i;
757
758 /* 'O'utput */
759 gdbmsgbuf[0] = 'O';
760
761 /* Fill and send buffers... */
762 while (len > 0) {
763 bufptr = gdbmsgbuf + 1;
764
765 /* Calculate how many this time */
766 if ((len << 1) > (BUFMAX - 2))
767 wcount = (BUFMAX - 2) >> 1;
768 else
769 wcount = len;
770
771 /* Pack in hex chars */
772 for (i = 0; i < wcount; i++)
773 bufptr = pack_hex_byte(bufptr, s[i]);
774 *bufptr = '\0';
775
776 /* Move up */
777 s += wcount;
778 len -= wcount;
779
780 /* Write packet */
781 put_packet(gdbmsgbuf);
782 }
783}
784
785/*
786 * Return true if there is a valid kgdb I/O module. Also if no
787 * debugger is attached a message can be printed to the console about
788 * waiting for the debugger to attach.
789 *
790 * The print_wait argument is only to be true when called from inside
791 * the core kgdb_handle_exception, because it will wait for the
792 * debugger to attach.
793 */
794static int kgdb_io_ready(int print_wait)
795{
796 if (!kgdb_io_ops)
797 return 0;
798 if (kgdb_connected)
799 return 1;
800 if (atomic_read(&kgdb_setting_breakpoint))
801 return 1;
802 if (print_wait)
803 printk(KERN_CRIT "KGDB: Waiting for remote debugger\n");
804 return 1;
805}
806
807/*
808 * All the functions that start with gdb_cmd are the various
809 * operations to implement the handlers for the gdbserial protocol
810 * where KGDB is communicating with an external debugger
811 */
812
813/* Handle the '?' status packets */
814static void gdb_cmd_status(struct kgdb_state *ks)
815{
816 /*
817 * We know that this packet is only sent
818 * during initial connect. So to be safe,
819 * we clear out our breakpoints now in case
820 * GDB is reconnecting.
821 */
822 remove_all_break();
823
824 remcom_out_buffer[0] = 'S';
825 pack_hex_byte(&remcom_out_buffer[1], ks->signo);
826}
827
828/* Handle the 'g' get registers request */
829static void gdb_cmd_getregs(struct kgdb_state *ks)
830{
831 struct task_struct *thread;
832 void *local_debuggerinfo;
833 int i;
834
835 thread = kgdb_usethread;
836 if (!thread) {
837 thread = kgdb_info[ks->cpu].task;
838 local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
839 } else {
840 local_debuggerinfo = NULL;
841 for (i = 0; i < NR_CPUS; i++) {
842 /*
843 * Try to find the task on some other
844 * or possibly this node if we do not
845 * find the matching task then we try
846 * to approximate the results.
847 */
848 if (thread == kgdb_info[i].task)
849 local_debuggerinfo = kgdb_info[i].debuggerinfo;
850 }
851 }
852
853 /*
854 * All threads that don't have debuggerinfo should be
855 * in __schedule() sleeping, since all other CPUs
856 * are in kgdb_wait, and thus have debuggerinfo.
857 */
858 if (local_debuggerinfo) {
859 pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
860 } else {
861 /*
862 * Pull stuff saved during switch_to; nothing
863 * else is accessible (or even particularly
864 * relevant).
865 *
866 * This should be enough for a stack trace.
867 */
868 sleeping_thread_to_gdb_regs(gdb_regs, thread);
869 }
870 kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
871}
872
873/* Handle the 'G' set registers request */
874static void gdb_cmd_setregs(struct kgdb_state *ks)
875{
876 kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
877
878 if (kgdb_usethread && kgdb_usethread != current) {
879 error_packet(remcom_out_buffer, -EINVAL);
880 } else {
881 gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
882 strcpy(remcom_out_buffer, "OK");
883 }
884}
885
886/* Handle the 'm' memory read bytes */
887static void gdb_cmd_memread(struct kgdb_state *ks)
888{
889 char *ptr = &remcom_in_buffer[1];
890 unsigned long length;
891 unsigned long addr;
892 int err;
893
894 if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
895 kgdb_hex2long(&ptr, &length) > 0) {
896 err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
897 if (err)
898 error_packet(remcom_out_buffer, err);
899 } else {
900 error_packet(remcom_out_buffer, -EINVAL);
901 }
902}
903
904/* Handle the 'M' memory write bytes */
905static void gdb_cmd_memwrite(struct kgdb_state *ks)
906{
907 int err = write_mem_msg(0);
908
909 if (err)
910 error_packet(remcom_out_buffer, err);
911 else
912 strcpy(remcom_out_buffer, "OK");
913}
914
915/* Handle the 'X' memory binary write bytes */
916static void gdb_cmd_binwrite(struct kgdb_state *ks)
917{
918 int err = write_mem_msg(1);
919
920 if (err)
921 error_packet(remcom_out_buffer, err);
922 else
923 strcpy(remcom_out_buffer, "OK");
924}
925
926/* Handle the 'D' or 'k', detach or kill packets */
927static void gdb_cmd_detachkill(struct kgdb_state *ks)
928{
929 int error;
930
931 /* The detach case */
932 if (remcom_in_buffer[0] == 'D') {
933 error = remove_all_break();
934 if (error < 0) {
935 error_packet(remcom_out_buffer, error);
936 } else {
937 strcpy(remcom_out_buffer, "OK");
938 kgdb_connected = 0;
939 }
940 put_packet(remcom_out_buffer);
941 } else {
942 /*
943 * Assume the kill case, with no exit code checking,
944 * trying to force detach the debugger:
945 */
946 remove_all_break();
947 kgdb_connected = 0;
948 }
949}
950
951/* Handle the 'R' reboot packets */
952static int gdb_cmd_reboot(struct kgdb_state *ks)
953{
954 /* For now, only honor R0 */
955 if (strcmp(remcom_in_buffer, "R0") == 0) {
956 printk(KERN_CRIT "Executing emergency reboot\n");
957 strcpy(remcom_out_buffer, "OK");
958 put_packet(remcom_out_buffer);
959
960 /*
961 * Execution should not return from
962 * machine_emergency_restart()
963 */
964 machine_emergency_restart();
965 kgdb_connected = 0;
966
967 return 1;
968 }
969 return 0;
970}
971
972/* Handle the 'q' query packets */
973static void gdb_cmd_query(struct kgdb_state *ks)
974{
975 struct task_struct *thread;
976 unsigned char thref[8];
977 char *ptr;
978 int i;
979
980 switch (remcom_in_buffer[1]) {
981 case 's':
982 case 'f':
983 if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) {
984 error_packet(remcom_out_buffer, -EINVAL);
985 break;
986 }
987
988 if (remcom_in_buffer[1] == 'f')
989 ks->threadid = 1;
990
991 remcom_out_buffer[0] = 'm';
992 ptr = remcom_out_buffer + 1;
993
994 for (i = 0; i < 17; ks->threadid++) {
995 thread = getthread(ks->linux_regs, ks->threadid);
996 if (thread) {
997 int_to_threadref(thref, ks->threadid);
998 pack_threadid(ptr, thref);
999 ptr += BUF_THREAD_ID_SIZE;
1000 *(ptr++) = ',';
1001 i++;
1002 }
1003 }
1004 *(--ptr) = '\0';
1005 break;
1006
1007 case 'C':
1008 /* Current thread id */
1009 strcpy(remcom_out_buffer, "QC");
1010 ks->threadid = shadow_pid(current->pid);
1011 int_to_threadref(thref, ks->threadid);
1012 pack_threadid(remcom_out_buffer + 2, thref);
1013 break;
1014 case 'T':
1015 if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) {
1016 error_packet(remcom_out_buffer, -EINVAL);
1017 break;
1018 }
1019 ks->threadid = 0;
1020 ptr = remcom_in_buffer + 17;
1021 kgdb_hex2long(&ptr, &ks->threadid);
1022 if (!getthread(ks->linux_regs, ks->threadid)) {
1023 error_packet(remcom_out_buffer, -EINVAL);
1024 break;
1025 }
1026 if (ks->threadid > 0) {
1027 kgdb_mem2hex(getthread(ks->linux_regs,
1028 ks->threadid)->comm,
1029 remcom_out_buffer, 16);
1030 } else {
1031 static char tmpstr[23 + BUF_THREAD_ID_SIZE];
1032
1033 sprintf(tmpstr, "Shadow task %d for pid 0",
1034 (int)(-ks->threadid-1));
1035 kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
1036 }
1037 break;
1038 }
1039}
1040
1041/* Handle the 'H' task query packets */
1042static void gdb_cmd_task(struct kgdb_state *ks)
1043{
1044 struct task_struct *thread;
1045 char *ptr;
1046
1047 switch (remcom_in_buffer[1]) {
1048 case 'g':
1049 ptr = &remcom_in_buffer[2];
1050 kgdb_hex2long(&ptr, &ks->threadid);
1051 thread = getthread(ks->linux_regs, ks->threadid);
1052 if (!thread && ks->threadid > 0) {
1053 error_packet(remcom_out_buffer, -EINVAL);
1054 break;
1055 }
1056 kgdb_usethread = thread;
1057 ks->kgdb_usethreadid = ks->threadid;
1058 strcpy(remcom_out_buffer, "OK");
1059 break;
1060 case 'c':
1061 ptr = &remcom_in_buffer[2];
1062 kgdb_hex2long(&ptr, &ks->threadid);
1063 if (!ks->threadid) {
1064 kgdb_contthread = NULL;
1065 } else {
1066 thread = getthread(ks->linux_regs, ks->threadid);
1067 if (!thread && ks->threadid > 0) {
1068 error_packet(remcom_out_buffer, -EINVAL);
1069 break;
1070 }
1071 kgdb_contthread = thread;
1072 }
1073 strcpy(remcom_out_buffer, "OK");
1074 break;
1075 }
1076}
1077
1078/* Handle the 'T' thread query packets */
1079static void gdb_cmd_thread(struct kgdb_state *ks)
1080{
1081 char *ptr = &remcom_in_buffer[1];
1082 struct task_struct *thread;
1083
1084 kgdb_hex2long(&ptr, &ks->threadid);
1085 thread = getthread(ks->linux_regs, ks->threadid);
1086 if (thread)
1087 strcpy(remcom_out_buffer, "OK");
1088 else
1089 error_packet(remcom_out_buffer, -EINVAL);
1090}
1091
1092/* Handle the 'z' or 'Z' breakpoint remove or set packets */
1093static void gdb_cmd_break(struct kgdb_state *ks)
1094{
1095 /*
1096 * Since GDB-5.3, it's been drafted that '0' is a software
1097 * breakpoint, '1' is a hardware breakpoint, so let's do that.
1098 */
1099 char *bpt_type = &remcom_in_buffer[1];
1100 char *ptr = &remcom_in_buffer[2];
1101 unsigned long addr;
1102 unsigned long length;
1103 int error = 0;
1104
1105 if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
1106 /* Unsupported */
1107 if (*bpt_type > '4')
1108 return;
1109 } else {
1110 if (*bpt_type != '0' && *bpt_type != '1')
1111 /* Unsupported. */
1112 return;
1113 }
1114
1115 /*
1116 * Test if this is a hardware breakpoint, and
1117 * if we support it:
1118 */
1119 if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
1120 /* Unsupported. */
1121 return;
1122
1123 if (*(ptr++) != ',') {
1124 error_packet(remcom_out_buffer, -EINVAL);
1125 return;
1126 }
1127 if (!kgdb_hex2long(&ptr, &addr)) {
1128 error_packet(remcom_out_buffer, -EINVAL);
1129 return;
1130 }
1131 if (*(ptr++) != ',' ||
1132 !kgdb_hex2long(&ptr, &length)) {
1133 error_packet(remcom_out_buffer, -EINVAL);
1134 return;
1135 }
1136
1137 if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
1138 error = kgdb_set_sw_break(addr);
1139 else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
1140 error = kgdb_remove_sw_break(addr);
1141 else if (remcom_in_buffer[0] == 'Z')
1142 error = arch_kgdb_ops.set_hw_breakpoint(addr,
1143 (int)length, *bpt_type - '0');
1144 else if (remcom_in_buffer[0] == 'z')
1145 error = arch_kgdb_ops.remove_hw_breakpoint(addr,
1146 (int) length, *bpt_type - '0');
1147
1148 if (error == 0)
1149 strcpy(remcom_out_buffer, "OK");
1150 else
1151 error_packet(remcom_out_buffer, error);
1152}
1153
1154/* Handle the 'C' signal / exception passing packets */
1155static int gdb_cmd_exception_pass(struct kgdb_state *ks)
1156{
1157 /* C09 == pass exception
1158 * C15 == detach kgdb, pass exception
1159 */
1160 if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
1161
1162 ks->pass_exception = 1;
1163 remcom_in_buffer[0] = 'c';
1164
1165 } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
1166
1167 ks->pass_exception = 1;
1168 remcom_in_buffer[0] = 'D';
1169 remove_all_break();
1170 kgdb_connected = 0;
1171 return 1;
1172
1173 } else {
1174 error_packet(remcom_out_buffer, -EINVAL);
1175 return 0;
1176 }
1177
1178 /* Indicate fall through */
1179 return -1;
1180}
1181
1182/*
1183 * This function performs all gdbserial command procesing
1184 */
1185static int gdb_serial_stub(struct kgdb_state *ks)
1186{
1187 int error = 0;
1188 int tmp;
1189
1190 /* Clear the out buffer. */
1191 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
1192
1193 if (kgdb_connected) {
1194 unsigned char thref[8];
1195 char *ptr;
1196
1197 /* Reply to host that an exception has occurred */
1198 ptr = remcom_out_buffer;
1199 *ptr++ = 'T';
1200 ptr = pack_hex_byte(ptr, ks->signo);
1201 ptr += strlen(strcpy(ptr, "thread:"));
1202 int_to_threadref(thref, shadow_pid(current->pid));
1203 ptr = pack_threadid(ptr, thref);
1204 *ptr++ = ';';
1205 put_packet(remcom_out_buffer);
1206 }
1207
1208 kgdb_usethread = kgdb_info[ks->cpu].task;
1209 ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
1210 ks->pass_exception = 0;
1211
1212 while (1) {
1213 error = 0;
1214
1215 /* Clear the out buffer. */
1216 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
1217
1218 get_packet(remcom_in_buffer);
1219
1220 switch (remcom_in_buffer[0]) {
1221 case '?': /* gdbserial status */
1222 gdb_cmd_status(ks);
1223 break;
1224 case 'g': /* return the value of the CPU registers */
1225 gdb_cmd_getregs(ks);
1226 break;
1227 case 'G': /* set the value of the CPU registers - return OK */
1228 gdb_cmd_setregs(ks);
1229 break;
1230 case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */
1231 gdb_cmd_memread(ks);
1232 break;
1233 case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
1234 gdb_cmd_memwrite(ks);
1235 break;
1236 case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
1237 gdb_cmd_binwrite(ks);
1238 break;
1239 /* kill or detach. KGDB should treat this like a
1240 * continue.
1241 */
1242 case 'D': /* Debugger detach */
1243 case 'k': /* Debugger detach via kill */
1244 gdb_cmd_detachkill(ks);
1245 goto default_handle;
1246 case 'R': /* Reboot */
1247 if (gdb_cmd_reboot(ks))
1248 goto default_handle;
1249 break;
1250 case 'q': /* query command */
1251 gdb_cmd_query(ks);
1252 break;
1253 case 'H': /* task related */
1254 gdb_cmd_task(ks);
1255 break;
1256 case 'T': /* Query thread status */
1257 gdb_cmd_thread(ks);
1258 break;
1259 case 'z': /* Break point remove */
1260 case 'Z': /* Break point set */
1261 gdb_cmd_break(ks);
1262 break;
1263 case 'C': /* Exception passing */
1264 tmp = gdb_cmd_exception_pass(ks);
1265 if (tmp > 0)
1266 goto default_handle;
1267 if (tmp == 0)
1268 break;
1269 /* Fall through on tmp < 0 */
1270 case 'c': /* Continue packet */
1271 case 's': /* Single step packet */
1272 if (kgdb_contthread && kgdb_contthread != current) {
1273 /* Can't switch threads in kgdb */
1274 error_packet(remcom_out_buffer, -EINVAL);
1275 break;
1276 }
1277 kgdb_activate_sw_breakpoints();
1278 /* Fall through to default processing */
1279 default:
1280default_handle:
1281 error = kgdb_arch_handle_exception(ks->ex_vector,
1282 ks->signo,
1283 ks->err_code,
1284 remcom_in_buffer,
1285 remcom_out_buffer,
1286 ks->linux_regs);
1287 /*
1288 * Leave cmd processing on error, detach,
1289 * kill, continue, or single step.
1290 */
1291 if (error >= 0 || remcom_in_buffer[0] == 'D' ||
1292 remcom_in_buffer[0] == 'k') {
1293 error = 0;
1294 goto kgdb_exit;
1295 }
1296
1297 }
1298
1299 /* reply to the request */
1300 put_packet(remcom_out_buffer);
1301 }
1302
1303kgdb_exit:
1304 if (ks->pass_exception)
1305 error = 1;
1306 return error;
1307}
1308
1309static int kgdb_reenter_check(struct kgdb_state *ks)
1310{
1311 unsigned long addr;
1312
1313 if (atomic_read(&kgdb_active) != raw_smp_processor_id())
1314 return 0;
1315
1316 /* Panic on recursive debugger calls: */
1317 exception_level++;
1318 addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
1319 kgdb_deactivate_sw_breakpoints();
1320
1321 /*
1322 * If the break point removed ok at the place exception
1323 * occurred, try to recover and print a warning to the end
1324 * user because the user planted a breakpoint in a place that
1325 * KGDB needs in order to function.
1326 */
1327 if (kgdb_remove_sw_break(addr) == 0) {
1328 exception_level = 0;
1329 kgdb_skipexception(ks->ex_vector, ks->linux_regs);
1330 kgdb_activate_sw_breakpoints();
1331 printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed %lx\n",
1332 addr);
1333 WARN_ON_ONCE(1);
1334
1335 return 1;
1336 }
1337 remove_all_break();
1338 kgdb_skipexception(ks->ex_vector, ks->linux_regs);
1339
1340 if (exception_level > 1) {
1341 dump_stack();
1342 panic("Recursive entry to debugger");
1343 }
1344
1345 printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n");
1346 dump_stack();
1347 panic("Recursive entry to debugger");
1348
1349 return 1;
1350}
1351
1352/*
1353 * kgdb_handle_exception() - main entry point from a kernel exception
1354 *
1355 * Locking hierarchy:
1356 * interface locks, if any (begin_session)
1357 * kgdb lock (kgdb_active)
1358 */
1359int
1360kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
1361{
1362 struct kgdb_state kgdb_var;
1363 struct kgdb_state *ks = &kgdb_var;
1364 unsigned long flags;
1365 int error = 0;
1366 int i, cpu;
1367
1368 ks->cpu = raw_smp_processor_id();
1369 ks->ex_vector = evector;
1370 ks->signo = signo;
1371 ks->ex_vector = evector;
1372 ks->err_code = ecode;
1373 ks->kgdb_usethreadid = 0;
1374 ks->linux_regs = regs;
1375
1376 if (kgdb_reenter_check(ks))
1377 return 0; /* Ouch, double exception ! */
1378
1379acquirelock:
1380 /*
1381 * Interrupts will be restored by the 'trap return' code, except when
1382 * single stepping.
1383 */
1384 local_irq_save(flags);
1385
1386 cpu = raw_smp_processor_id();
1387
1388 /*
1389 * Acquire the kgdb_active lock:
1390 */
1391 while (atomic_cmpxchg(&kgdb_active, -1, cpu) != -1)
1392 cpu_relax();
1393
1394 /*
1395 * Do not start the debugger connection on this CPU if the last
1396 * instance of the exception handler wanted to come into the
1397 * debugger on a different CPU via a single step
1398 */
1399 if (atomic_read(&kgdb_cpu_doing_single_step) != -1 &&
1400 atomic_read(&kgdb_cpu_doing_single_step) != cpu) {
1401
1402 atomic_set(&kgdb_active, -1);
1403 clocksource_touch_watchdog();
1404 local_irq_restore(flags);
1405
1406 goto acquirelock;
1407 }
1408
1409 if (!kgdb_io_ready(1)) {
1410 error = 1;
1411 goto kgdb_restore; /* No I/O connection, so resume the system */
1412 }
1413
1414 /*
1415 * Don't enter if we have hit a removed breakpoint.
1416 */
1417 if (kgdb_skipexception(ks->ex_vector, ks->linux_regs))
1418 goto kgdb_restore;
1419
1420 /* Call the I/O driver's pre_exception routine */
1421 if (kgdb_io_ops->pre_exception)
1422 kgdb_io_ops->pre_exception();
1423
1424 kgdb_info[ks->cpu].debuggerinfo = ks->linux_regs;
1425 kgdb_info[ks->cpu].task = current;
1426
1427 kgdb_disable_hw_debug(ks->linux_regs);
1428
1429 /*
1430 * Get the passive CPU lock which will hold all the non-primary
1431 * CPU in a spin state while the debugger is active
1432 */
1433 if (!kgdb_single_step || !kgdb_contthread) {
1434 for (i = 0; i < NR_CPUS; i++)
1435 atomic_set(&passive_cpu_wait[i], 1);
1436 }
1437
1438 /*
1439 * spin_lock code is good enough as a barrier so we don't
1440 * need one here:
1441 */
1442 atomic_set(&cpu_in_kgdb[ks->cpu], 1);
1443
1444#ifdef CONFIG_SMP
1445 /* Signal the other CPUs to enter kgdb_wait() */
1446 if ((!kgdb_single_step || !kgdb_contthread) && kgdb_do_roundup)
1447 kgdb_roundup_cpus(flags);
1448#endif
1449
1450 /*
1451 * Wait for the other CPUs to be notified and be waiting for us:
1452 */
1453 for_each_online_cpu(i) {
1454 while (!atomic_read(&cpu_in_kgdb[i]))
1455 cpu_relax();
1456 }
1457
1458 /*
1459 * At this point the primary processor is completely
1460 * in the debugger and all secondary CPUs are quiescent
1461 */
1462 kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code);
1463 kgdb_deactivate_sw_breakpoints();
1464 kgdb_single_step = 0;
1465 kgdb_contthread = NULL;
1466 exception_level = 0;
1467
1468 /* Talk to debugger with gdbserial protocol */
1469 error = gdb_serial_stub(ks);
1470
1471 /* Call the I/O driver's post_exception routine */
1472 if (kgdb_io_ops->post_exception)
1473 kgdb_io_ops->post_exception();
1474
1475 kgdb_info[ks->cpu].debuggerinfo = NULL;
1476 kgdb_info[ks->cpu].task = NULL;
1477 atomic_set(&cpu_in_kgdb[ks->cpu], 0);
1478
1479 if (!kgdb_single_step || !kgdb_contthread) {
1480 for (i = NR_CPUS-1; i >= 0; i--)
1481 atomic_set(&passive_cpu_wait[i], 0);
1482 /*
1483 * Wait till all the CPUs have quit
1484 * from the debugger.
1485 */
1486 for_each_online_cpu(i) {
1487 while (atomic_read(&cpu_in_kgdb[i]))
1488 cpu_relax();
1489 }
1490 }
1491
1492kgdb_restore:
1493 /* Free kgdb_active */
1494 atomic_set(&kgdb_active, -1);
1495 clocksource_touch_watchdog();
1496 local_irq_restore(flags);
1497
1498 return error;
1499}
1500
1501int kgdb_nmicallback(int cpu, void *regs)
1502{
1503#ifdef CONFIG_SMP
1504 if (!atomic_read(&cpu_in_kgdb[cpu]) &&
1505 atomic_read(&kgdb_active) != cpu &&
1506 atomic_read(&cpu_in_kgdb[atomic_read(&kgdb_active)])) {
1507 kgdb_wait((struct pt_regs *)regs);
1508 return 0;
1509 }
1510#endif
1511 return 1;
1512}
1513
1514void kgdb_console_write(struct console *co, const char *s, unsigned count)
1515{
1516 unsigned long flags;
1517
1518 /* If we're debugging, or KGDB has not connected, don't try
1519 * and print. */
1520 if (!kgdb_connected || atomic_read(&kgdb_active) != -1)
1521 return;
1522
1523 local_irq_save(flags);
1524 kgdb_msg_write(s, count);
1525 local_irq_restore(flags);
1526}
1527
1528static struct console kgdbcons = {
1529 .name = "kgdb",
1530 .write = kgdb_console_write,
1531 .flags = CON_PRINTBUFFER | CON_ENABLED,
1532 .index = -1,
1533};
1534
1535#ifdef CONFIG_MAGIC_SYSRQ
1536static void sysrq_handle_gdb(int key, struct tty_struct *tty)
1537{
1538 if (!kgdb_io_ops) {
1539 printk(KERN_CRIT "ERROR: No KGDB I/O module available\n");
1540 return;
1541 }
1542 if (!kgdb_connected)
1543 printk(KERN_CRIT "Entering KGDB\n");
1544
1545 kgdb_breakpoint();
1546}
1547
1548static struct sysrq_key_op sysrq_gdb_op = {
1549 .handler = sysrq_handle_gdb,
1550 .help_msg = "Gdb",
1551 .action_msg = "GDB",
1552};
1553#endif
1554
1555static void kgdb_register_callbacks(void)
1556{
1557 if (!kgdb_io_module_registered) {
1558 kgdb_io_module_registered = 1;
1559 kgdb_arch_init();
1560#ifdef CONFIG_MAGIC_SYSRQ
1561 register_sysrq_key('g', &sysrq_gdb_op);
1562#endif
1563 if (kgdb_use_con && !kgdb_con_registered) {
1564 register_console(&kgdbcons);
1565 kgdb_con_registered = 1;
1566 }
1567 }
1568}
1569
1570static void kgdb_unregister_callbacks(void)
1571{
1572 /*
1573 * When this routine is called KGDB should unregister from the
1574 * panic handler and clean up, making sure it is not handling any
1575 * break exceptions at the time.
1576 */
1577 if (kgdb_io_module_registered) {
1578 kgdb_io_module_registered = 0;
1579 kgdb_arch_exit();
1580#ifdef CONFIG_MAGIC_SYSRQ
1581 unregister_sysrq_key('g', &sysrq_gdb_op);
1582#endif
1583 if (kgdb_con_registered) {
1584 unregister_console(&kgdbcons);
1585 kgdb_con_registered = 0;
1586 }
1587 }
1588}
1589
1590static void kgdb_initial_breakpoint(void)
1591{
1592 kgdb_break_asap = 0;
1593
1594 printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n");
1595 kgdb_breakpoint();
1596}
1597
1598/**
1599 * kgdb_register_io_module - register KGDB IO module
1600 * @new_kgdb_io_ops: the io ops vector
1601 *
1602 * Register it with the KGDB core.
1603 */
1604int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops)
1605{
1606 int err;
1607
1608 spin_lock(&kgdb_registration_lock);
1609
1610 if (kgdb_io_ops) {
1611 spin_unlock(&kgdb_registration_lock);
1612
1613 printk(KERN_ERR "kgdb: Another I/O driver is already "
1614 "registered with KGDB.\n");
1615 return -EBUSY;
1616 }
1617
1618 if (new_kgdb_io_ops->init) {
1619 err = new_kgdb_io_ops->init();
1620 if (err) {
1621 spin_unlock(&kgdb_registration_lock);
1622 return err;
1623 }
1624 }
1625
1626 kgdb_io_ops = new_kgdb_io_ops;
1627
1628 spin_unlock(&kgdb_registration_lock);
1629
1630 printk(KERN_INFO "kgdb: Registered I/O driver %s.\n",
1631 new_kgdb_io_ops->name);
1632
1633 /* Arm KGDB now. */
1634 kgdb_register_callbacks();
1635
1636 if (kgdb_break_asap)
1637 kgdb_initial_breakpoint();
1638
1639 return 0;
1640}
1641EXPORT_SYMBOL_GPL(kgdb_register_io_module);
1642
1643/**
1644 * kkgdb_unregister_io_module - unregister KGDB IO module
1645 * @old_kgdb_io_ops: the io ops vector
1646 *
1647 * Unregister it with the KGDB core.
1648 */
1649void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops)
1650{
1651 BUG_ON(kgdb_connected);
1652
1653 /*
1654 * KGDB is no longer able to communicate out, so
1655 * unregister our callbacks and reset state.
1656 */
1657 kgdb_unregister_callbacks();
1658
1659 spin_lock(&kgdb_registration_lock);
1660
1661 WARN_ON_ONCE(kgdb_io_ops != old_kgdb_io_ops);
1662 kgdb_io_ops = NULL;
1663
1664 spin_unlock(&kgdb_registration_lock);
1665
1666 printk(KERN_INFO
1667 "kgdb: Unregistered I/O driver %s, debugger disabled.\n",
1668 old_kgdb_io_ops->name);
1669}
1670EXPORT_SYMBOL_GPL(kgdb_unregister_io_module);
1671
1672/**
1673 * kgdb_breakpoint - generate breakpoint exception
1674 *
1675 * This function will generate a breakpoint exception. It is used at the
1676 * beginning of a program to sync up with a debugger and can be used
1677 * otherwise as a quick means to stop program execution and "break" into
1678 * the debugger.
1679 */
1680void kgdb_breakpoint(void)
1681{
1682 atomic_set(&kgdb_setting_breakpoint, 1);
1683 wmb(); /* Sync point before breakpoint */
1684 arch_kgdb_breakpoint();
1685 wmb(); /* Sync point after breakpoint */
1686 atomic_set(&kgdb_setting_breakpoint, 0);
1687}
1688EXPORT_SYMBOL_GPL(kgdb_breakpoint);
1689
1690static int __init opt_kgdb_wait(char *str)
1691{
1692 kgdb_break_asap = 1;
1693
1694 if (kgdb_io_module_registered)
1695 kgdb_initial_breakpoint();
1696
1697 return 0;
1698}
1699
1700early_param("kgdbwait", opt_kgdb_wait);
generated by cgit v1.2.2 (git 2.25.0) at 2025-11-01 21:27:26 -0400