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-rw-r--r--kernel/kgdb.c1693
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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/interrupt.h>
32#include <linux/spinlock.h>
33#include <linux/console.h>
34#include <linux/threads.h>
35#include <linux/uaccess.h>
36#include <linux/kernel.h>
37#include <linux/module.h>
38#include <linux/ptrace.h>
39#include <linux/reboot.h>
40#include <linux/string.h>
41#include <linux/delay.h>
42#include <linux/sched.h>
43#include <linux/sysrq.h>
44#include <linux/init.h>
45#include <linux/kgdb.h>
46#include <linux/pid.h>
47#include <linux/smp.h>
48#include <linux/mm.h>
49
50#include <asm/cacheflush.h>
51#include <asm/byteorder.h>
52#include <asm/atomic.h>
53#include <asm/system.h>
54
55static int kgdb_break_asap;
56
57struct kgdb_state {
58 int ex_vector;
59 int signo;
60 int err_code;
61 int cpu;
62 int pass_exception;
63 long threadid;
64 long kgdb_usethreadid;
65 struct pt_regs *linux_regs;
66};
67
68static struct debuggerinfo_struct {
69 void *debuggerinfo;
70 struct task_struct *task;
71} kgdb_info[NR_CPUS];
72
73/**
74 * kgdb_connected - Is a host GDB connected to us?
75 */
76int kgdb_connected;
77EXPORT_SYMBOL_GPL(kgdb_connected);
78
79/* All the KGDB handlers are installed */
80static int kgdb_io_module_registered;
81
82/* Guard for recursive entry */
83static int exception_level;
84
85static struct kgdb_io *kgdb_io_ops;
86static DEFINE_SPINLOCK(kgdb_registration_lock);
87
88/* kgdb console driver is loaded */
89static int kgdb_con_registered;
90/* determine if kgdb console output should be used */
91static int kgdb_use_con;
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);
102
103/*
104 * Holds information about breakpoints in a kernel. These breakpoints are
105 * added and removed by gdb.
106 */
107static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = {
108 [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED }
109};
110
111/*
112 * The CPU# of the active CPU, or -1 if none:
113 */
114atomic_t kgdb_active = ATOMIC_INIT(-1);
115
116/*
117 * We use NR_CPUs not PERCPU, in case kgdb is used to debug early
118 * bootup code (which might not have percpu set up yet):
119 */
120static atomic_t passive_cpu_wait[NR_CPUS];
121static atomic_t cpu_in_kgdb[NR_CPUS];
122atomic_t kgdb_setting_breakpoint;
123
124struct task_struct *kgdb_usethread;
125struct task_struct *kgdb_contthread;
126
127int kgdb_single_step;
128
129/* Our I/O buffers. */
130static char remcom_in_buffer[BUFMAX];
131static char remcom_out_buffer[BUFMAX];
132
133/* Storage for the registers, in GDB format. */
134static unsigned long gdb_regs[(NUMREGBYTES +
135 sizeof(unsigned long) - 1) /
136 sizeof(unsigned long)];
137
138/* to keep track of the CPU which is doing the single stepping*/
139atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1);
140
141/*
142 * If you are debugging a problem where roundup (the collection of
143 * all other CPUs) is a problem [this should be extremely rare],
144 * then use the nokgdbroundup option to avoid roundup. In that case
145 * the other CPUs might interfere with your debugging context, so
146 * use this with care:
147 */
148int kgdb_do_roundup = 1;
149
150static int __init opt_nokgdbroundup(char *str)
151{
152 kgdb_do_roundup = 0;
153
154 return 0;
155}
156
157early_param("nokgdbroundup", opt_nokgdbroundup);
158
159/*
160 * Finally, some KGDB code :-)
161 */
162
163/*
164 * Weak aliases for breakpoint management,
165 * can be overriden by architectures when needed:
166 */
167int __weak kgdb_validate_break_address(unsigned long addr)
168{
169 char tmp_variable[BREAK_INSTR_SIZE];
170
171 return probe_kernel_read(tmp_variable, (char *)addr, BREAK_INSTR_SIZE);
172}
173
174int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
175{
176 int err;
177
178 err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE);
179 if (err)
180 return err;
181
182 return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr,
183 BREAK_INSTR_SIZE);
184}
185
186int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle)
187{
188 return probe_kernel_write((char *)addr,
189 (char *)bundle, BREAK_INSTR_SIZE);
190}
191
192unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
193{
194 return instruction_pointer(regs);
195}
196
197int __weak kgdb_arch_init(void)
198{
199 return 0;
200}
201
202/**
203 * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
204 * @regs: Current &struct pt_regs.
205 *
206 * This function will be called if the particular architecture must
207 * disable hardware debugging while it is processing gdb packets or
208 * handling exception.
209 */
210void __weak kgdb_disable_hw_debug(struct pt_regs *regs)
211{
212}
213
214/*
215 * GDB remote protocol parser:
216 */
217
218static const char hexchars[] = "0123456789abcdef";
219
220static int hex(char ch)
221{
222 if ((ch >= 'a') && (ch <= 'f'))
223 return ch - 'a' + 10;
224 if ((ch >= '0') && (ch <= '9'))
225 return ch - '0';
226 if ((ch >= 'A') && (ch <= 'F'))
227 return ch - 'A' + 10;
228 return -1;
229}
230
231/* scan for the sequence $<data>#<checksum> */
232static void get_packet(char *buffer)
233{
234 unsigned char checksum;
235 unsigned char xmitcsum;
236 int count;
237 char ch;
238
239 do {
240 /*
241 * Spin and wait around for the start character, ignore all
242 * other characters:
243 */
244 while ((ch = (kgdb_io_ops->read_char())) != '$')
245 /* nothing */;
246
247 kgdb_connected = 1;
248 checksum = 0;
249 xmitcsum = -1;
250
251 count = 0;
252
253 /*
254 * now, read until a # or end of buffer is found:
255 */
256 while (count < (BUFMAX - 1)) {
257 ch = kgdb_io_ops->read_char();
258 if (ch == '#')
259 break;
260 checksum = checksum + ch;
261 buffer[count] = ch;
262 count = count + 1;
263 }
264 buffer[count] = 0;
265
266 if (ch == '#') {
267 xmitcsum = hex(kgdb_io_ops->read_char()) << 4;
268 xmitcsum += hex(kgdb_io_ops->read_char());
269
270 if (checksum != xmitcsum)
271 /* failed checksum */
272 kgdb_io_ops->write_char('-');
273 else
274 /* successful transfer */
275 kgdb_io_ops->write_char('+');
276 if (kgdb_io_ops->flush)
277 kgdb_io_ops->flush();
278 }
279 } while (checksum != xmitcsum);
280}
281
282/*
283 * Send the packet in buffer.
284 * Check for gdb connection if asked for.
285 */
286static void put_packet(char *buffer)
287{
288 unsigned char checksum;
289 int count;
290 char ch;
291
292 /*
293 * $<packet info>#<checksum>.
294 */
295 while (1) {
296 kgdb_io_ops->write_char('$');
297 checksum = 0;
298 count = 0;
299
300 while ((ch = buffer[count])) {
301 kgdb_io_ops->write_char(ch);
302 checksum += ch;
303 count++;
304 }
305
306 kgdb_io_ops->write_char('#');
307 kgdb_io_ops->write_char(hexchars[checksum >> 4]);
308 kgdb_io_ops->write_char(hexchars[checksum & 0xf]);
309 if (kgdb_io_ops->flush)
310 kgdb_io_ops->flush();
311
312 /* Now see what we get in reply. */
313 ch = kgdb_io_ops->read_char();
314
315 if (ch == 3)
316 ch = kgdb_io_ops->read_char();
317
318 /* If we get an ACK, we are done. */
319 if (ch == '+')
320 return;
321
322 /*
323 * If we get the start of another packet, this means
324 * that GDB is attempting to reconnect. We will NAK
325 * the packet being sent, and stop trying to send this
326 * packet.
327 */
328 if (ch == '$') {
329 kgdb_io_ops->write_char('-');
330 if (kgdb_io_ops->flush)
331 kgdb_io_ops->flush();
332 return;
333 }
334 }
335}
336
337static char *pack_hex_byte(char *pkt, u8 byte)
338{
339 *pkt++ = hexchars[byte >> 4];
340 *pkt++ = hexchars[byte & 0xf];
341
342 return pkt;
343}
344
345/*
346 * Convert the memory pointed to by mem into hex, placing result in buf.
347 * Return a pointer to the last char put in buf (null). May return an error.
348 */
349int kgdb_mem2hex(char *mem, char *buf, int count)
350{
351 char *tmp;
352 int err;
353
354 /*
355 * We use the upper half of buf as an intermediate buffer for the
356 * raw memory copy. Hex conversion will work against this one.
357 */
358 tmp = buf + count;
359
360 err = probe_kernel_read(tmp, mem, count);
361 if (!err) {
362 while (count > 0) {
363 buf = pack_hex_byte(buf, *tmp);
364 tmp++;
365 count--;
366 }
367
368 *buf = 0;
369 }
370
371 return err;
372}
373
374/*
375 * Copy the binary array pointed to by buf into mem. Fix $, #, and
376 * 0x7d escaped with 0x7d. Return a pointer to the character after
377 * the last byte written.
378 */
379static int kgdb_ebin2mem(char *buf, char *mem, int count)
380{
381 int err = 0;
382 char c;
383
384 while (count-- > 0) {
385 c = *buf++;
386 if (c == 0x7d)
387 c = *buf++ ^ 0x20;
388
389 err = probe_kernel_write(mem, &c, 1);
390 if (err)
391 break;
392
393 mem++;
394 }
395
396 return err;
397}
398
399/*
400 * Convert the hex array pointed to by buf into binary to be placed in mem.
401 * Return a pointer to the character AFTER the last byte written.
402 * May return an error.
403 */
404int kgdb_hex2mem(char *buf, char *mem, int count)
405{
406 char *tmp_raw;
407 char *tmp_hex;
408
409 /*
410 * We use the upper half of buf as an intermediate buffer for the
411 * raw memory that is converted from hex.
412 */
413 tmp_raw = buf + count * 2;
414
415 tmp_hex = tmp_raw - 1;
416 while (tmp_hex >= buf) {
417 tmp_raw--;
418 *tmp_raw = hex(*tmp_hex--);
419 *tmp_raw |= hex(*tmp_hex--) << 4;
420 }
421
422 return probe_kernel_write(mem, tmp_raw, count);
423}
424
425/*
426 * While we find nice hex chars, build a long_val.
427 * Return number of chars processed.
428 */
429int kgdb_hex2long(char **ptr, long *long_val)
430{
431 int hex_val;
432 int num = 0;
433
434 *long_val = 0;
435
436 while (**ptr) {
437 hex_val = hex(**ptr);
438 if (hex_val < 0)
439 break;
440
441 *long_val = (*long_val << 4) | hex_val;
442 num++;
443 (*ptr)++;
444 }
445
446 return num;
447}
448
449/* Write memory due to an 'M' or 'X' packet. */
450static int write_mem_msg(int binary)
451{
452 char *ptr = &remcom_in_buffer[1];
453 unsigned long addr;
454 unsigned long length;
455 int err;
456
457 if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
458 kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
459 if (binary)
460 err = kgdb_ebin2mem(ptr, (char *)addr, length);
461 else
462 err = kgdb_hex2mem(ptr, (char *)addr, length);
463 if (err)
464 return err;
465 if (CACHE_FLUSH_IS_SAFE)
466 flush_icache_range(addr, addr + length + 1);
467 return 0;
468 }
469
470 return -EINVAL;
471}
472
473static void error_packet(char *pkt, int error)
474{
475 error = -error;
476 pkt[0] = 'E';
477 pkt[1] = hexchars[(error / 10)];
478 pkt[2] = hexchars[(error % 10)];
479 pkt[3] = '\0';
480}
481
482/*
483 * Thread ID accessors. We represent a flat TID space to GDB, where
484 * the per CPU idle threads (which under Linux all have PID 0) are
485 * remapped to negative TIDs.
486 */
487
488#define BUF_THREAD_ID_SIZE 16
489
490static char *pack_threadid(char *pkt, unsigned char *id)
491{
492 char *limit;
493
494 limit = pkt + BUF_THREAD_ID_SIZE;
495 while (pkt < limit)
496 pkt = pack_hex_byte(pkt, *id++);
497
498 return pkt;
499}
500
501static void int_to_threadref(unsigned char *id, int value)
502{
503 unsigned char *scan;
504 int i = 4;
505
506 scan = (unsigned char *)id;
507 while (i--)
508 *scan++ = 0;
509 *scan++ = (value >> 24) & 0xff;
510 *scan++ = (value >> 16) & 0xff;
511 *scan++ = (value >> 8) & 0xff;
512 *scan++ = (value & 0xff);
513}
514
515static struct task_struct *getthread(struct pt_regs *regs, int tid)
516{
517 /*
518 * Non-positive TIDs are remapped idle tasks:
519 */
520 if (tid <= 0)
521 return idle_task(-tid);
522
523 /*
524 * find_task_by_pid_ns() does not take the tasklist lock anymore
525 * but is nicely RCU locked - hence is a pretty resilient
526 * thing to use:
527 */
528 return find_task_by_pid_ns(tid, &init_pid_ns);
529}
530
531/*
532 * CPU debug state control:
533 */
534
535#ifdef CONFIG_SMP
536static void kgdb_wait(struct pt_regs *regs)
537{
538 unsigned long flags;
539 int cpu;
540
541 local_irq_save(flags);
542 cpu = raw_smp_processor_id();
543 kgdb_info[cpu].debuggerinfo = regs;
544 kgdb_info[cpu].task = current;
545 /*
546 * Make sure the above info reaches the primary CPU before
547 * our cpu_in_kgdb[] flag setting does:
548 */
549 smp_wmb();
550 atomic_set(&cpu_in_kgdb[cpu], 1);
551
552 /*
553 * The primary CPU must be active to enter here, but this is
554 * guard in case the primary CPU had not been selected if
555 * this was an entry via nmi.
556 */
557 while (atomic_read(&kgdb_active) == -1)
558 cpu_relax();
559
560 /* Wait till primary CPU goes completely into the debugger. */
561 while (!atomic_read(&cpu_in_kgdb[atomic_read(&kgdb_active)]))
562 cpu_relax();
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 local_irq_restore(flags);
578}
579#endif
580
581/*
582 * Some architectures need cache flushes when we set/clear a
583 * breakpoint:
584 */
585static void kgdb_flush_swbreak_addr(unsigned long addr)
586{
587 if (!CACHE_FLUSH_IS_SAFE)
588 return;
589
590 if (current->mm) {
591 flush_cache_range(current->mm->mmap_cache,
592 addr, addr + BREAK_INSTR_SIZE);
593 } else {
594 flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
595 }
596}
597
598/*
599 * SW breakpoint management:
600 */
601static int kgdb_activate_sw_breakpoints(void)
602{
603 unsigned long addr;
604 int error = 0;
605 int i;
606
607 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
608 if (kgdb_break[i].state != BP_SET)
609 continue;
610
611 addr = kgdb_break[i].bpt_addr;
612 error = kgdb_arch_set_breakpoint(addr,
613 kgdb_break[i].saved_instr);
614 if (error)
615 return error;
616
617 kgdb_flush_swbreak_addr(addr);
618 kgdb_break[i].state = BP_ACTIVE;
619 }
620 return 0;
621}
622
623static int kgdb_set_sw_break(unsigned long addr)
624{
625 int err = kgdb_validate_break_address(addr);
626 int breakno = -1;
627 int i;
628
629 if (err)
630 return err;
631
632 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
633 if ((kgdb_break[i].state == BP_SET) &&
634 (kgdb_break[i].bpt_addr == addr))
635 return -EEXIST;
636 }
637 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
638 if (kgdb_break[i].state == BP_REMOVED &&
639 kgdb_break[i].bpt_addr == addr) {
640 breakno = i;
641 break;
642 }
643 }
644
645 if (breakno == -1) {
646 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
647 if (kgdb_break[i].state == BP_UNDEFINED) {
648 breakno = i;
649 break;
650 }
651 }
652 }
653
654 if (breakno == -1)
655 return -E2BIG;
656
657 kgdb_break[breakno].state = BP_SET;
658 kgdb_break[breakno].type = BP_BREAKPOINT;
659 kgdb_break[breakno].bpt_addr = addr;
660
661 return 0;
662}
663
664static int kgdb_deactivate_sw_breakpoints(void)
665{
666 unsigned long addr;
667 int error = 0;
668 int i;
669
670 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
671 if (kgdb_break[i].state != BP_ACTIVE)
672 continue;
673 addr = kgdb_break[i].bpt_addr;
674 error = kgdb_arch_remove_breakpoint(addr,
675 kgdb_break[i].saved_instr);
676 if (error)
677 return error;
678
679 kgdb_flush_swbreak_addr(addr);
680 kgdb_break[i].state = BP_SET;
681 }
682 return 0;
683}
684
685static int kgdb_remove_sw_break(unsigned long addr)
686{
687 int i;
688
689 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
690 if ((kgdb_break[i].state == BP_SET) &&
691 (kgdb_break[i].bpt_addr == addr)) {
692 kgdb_break[i].state = BP_REMOVED;
693 return 0;
694 }
695 }
696 return -ENOENT;
697}
698
699int kgdb_isremovedbreak(unsigned long addr)
700{
701 int i;
702
703 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
704 if ((kgdb_break[i].state == BP_REMOVED) &&
705 (kgdb_break[i].bpt_addr == addr))
706 return 1;
707 }
708 return 0;
709}
710
711int remove_all_break(void)
712{
713 unsigned long addr;
714 int error;
715 int i;
716
717 /* Clear memory breakpoints. */
718 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
719 if (kgdb_break[i].state != BP_SET)
720 continue;
721 addr = kgdb_break[i].bpt_addr;
722 error = kgdb_arch_remove_breakpoint(addr,
723 kgdb_break[i].saved_instr);
724 if (error)
725 return error;
726 kgdb_break[i].state = BP_REMOVED;
727 }
728
729 /* Clear hardware breakpoints. */
730 if (arch_kgdb_ops.remove_all_hw_break)
731 arch_kgdb_ops.remove_all_hw_break();
732
733 return 0;
734}
735
736/*
737 * Remap normal tasks to their real PID, idle tasks to -1 ... -NR_CPUs:
738 */
739static inline int shadow_pid(int realpid)
740{
741 if (realpid)
742 return realpid;
743
744 return -1-raw_smp_processor_id();
745}
746
747static char gdbmsgbuf[BUFMAX + 1];
748
749static void kgdb_msg_write(const char *s, int len)
750{
751 char *bufptr;
752 int wcount;
753 int i;
754
755 /* 'O'utput */
756 gdbmsgbuf[0] = 'O';
757
758 /* Fill and send buffers... */
759 while (len > 0) {
760 bufptr = gdbmsgbuf + 1;
761
762 /* Calculate how many this time */
763 if ((len << 1) > (BUFMAX - 2))
764 wcount = (BUFMAX - 2) >> 1;
765 else
766 wcount = len;
767
768 /* Pack in hex chars */
769 for (i = 0; i < wcount; i++)
770 bufptr = pack_hex_byte(bufptr, s[i]);
771 *bufptr = '\0';
772
773 /* Move up */
774 s += wcount;
775 len -= wcount;
776
777 /* Write packet */
778 put_packet(gdbmsgbuf);
779 }
780}
781
782/*
783 * Return true if there is a valid kgdb I/O module. Also if no
784 * debugger is attached a message can be printed to the console about
785 * waiting for the debugger to attach.
786 *
787 * The print_wait argument is only to be true when called from inside
788 * the core kgdb_handle_exception, because it will wait for the
789 * debugger to attach.
790 */
791static int kgdb_io_ready(int print_wait)
792{
793 if (!kgdb_io_ops)
794 return 0;
795 if (kgdb_connected)
796 return 1;
797 if (atomic_read(&kgdb_setting_breakpoint))
798 return 1;
799 if (print_wait)
800 printk(KERN_CRIT "KGDB: Waiting for remote debugger\n");
801 return 1;
802}
803
804/*
805 * All the functions that start with gdb_cmd are the various
806 * operations to implement the handlers for the gdbserial protocol
807 * where KGDB is communicating with an external debugger
808 */
809
810/* Handle the '?' status packets */
811static void gdb_cmd_status(struct kgdb_state *ks)
812{
813 /*
814 * We know that this packet is only sent
815 * during initial connect. So to be safe,
816 * we clear out our breakpoints now in case
817 * GDB is reconnecting.
818 */
819 remove_all_break();
820
821 remcom_out_buffer[0] = 'S';
822 pack_hex_byte(&remcom_out_buffer[1], ks->signo);
823}
824
825/* Handle the 'g' get registers request */
826static void gdb_cmd_getregs(struct kgdb_state *ks)
827{
828 struct task_struct *thread;
829 void *local_debuggerinfo;
830 int i;
831
832 thread = kgdb_usethread;
833 if (!thread) {
834 thread = kgdb_info[ks->cpu].task;
835 local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
836 } else {
837 local_debuggerinfo = NULL;
838 for (i = 0; i < NR_CPUS; i++) {
839 /*
840 * Try to find the task on some other
841 * or possibly this node if we do not
842 * find the matching task then we try
843 * to approximate the results.
844 */
845 if (thread == kgdb_info[i].task)
846 local_debuggerinfo = kgdb_info[i].debuggerinfo;
847 }
848 }
849
850 /*
851 * All threads that don't have debuggerinfo should be
852 * in __schedule() sleeping, since all other CPUs
853 * are in kgdb_wait, and thus have debuggerinfo.
854 */
855 if (local_debuggerinfo) {
856 pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
857 } else {
858 /*
859 * Pull stuff saved during switch_to; nothing
860 * else is accessible (or even particularly
861 * relevant).
862 *
863 * This should be enough for a stack trace.
864 */
865 sleeping_thread_to_gdb_regs(gdb_regs, thread);
866 }
867 kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
868}
869
870/* Handle the 'G' set registers request */
871static void gdb_cmd_setregs(struct kgdb_state *ks)
872{
873 kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
874
875 if (kgdb_usethread && kgdb_usethread != current) {
876 error_packet(remcom_out_buffer, -EINVAL);
877 } else {
878 gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
879 strcpy(remcom_out_buffer, "OK");
880 }
881}
882
883/* Handle the 'm' memory read bytes */
884static void gdb_cmd_memread(struct kgdb_state *ks)
885{
886 char *ptr = &remcom_in_buffer[1];
887 unsigned long length;
888 unsigned long addr;
889 int err;
890
891 if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
892 kgdb_hex2long(&ptr, &length) > 0) {
893 err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
894 if (err)
895 error_packet(remcom_out_buffer, err);
896 } else {
897 error_packet(remcom_out_buffer, -EINVAL);
898 }
899}
900
901/* Handle the 'M' memory write bytes */
902static void gdb_cmd_memwrite(struct kgdb_state *ks)
903{
904 int err = write_mem_msg(0);
905
906 if (err)
907 error_packet(remcom_out_buffer, err);
908 else
909 strcpy(remcom_out_buffer, "OK");
910}
911
912/* Handle the 'X' memory binary write bytes */
913static void gdb_cmd_binwrite(struct kgdb_state *ks)
914{
915 int err = write_mem_msg(1);
916
917 if (err)
918 error_packet(remcom_out_buffer, err);
919 else
920 strcpy(remcom_out_buffer, "OK");
921}
922
923/* Handle the 'D' or 'k', detach or kill packets */
924static void gdb_cmd_detachkill(struct kgdb_state *ks)
925{
926 int error;
927
928 /* The detach case */
929 if (remcom_in_buffer[0] == 'D') {
930 error = remove_all_break();
931 if (error < 0) {
932 error_packet(remcom_out_buffer, error);
933 } else {
934 strcpy(remcom_out_buffer, "OK");
935 kgdb_connected = 0;
936 }
937 put_packet(remcom_out_buffer);
938 } else {
939 /*
940 * Assume the kill case, with no exit code checking,
941 * trying to force detach the debugger:
942 */
943 remove_all_break();
944 kgdb_connected = 0;
945 }
946}
947
948/* Handle the 'R' reboot packets */
949static int gdb_cmd_reboot(struct kgdb_state *ks)
950{
951 /* For now, only honor R0 */
952 if (strcmp(remcom_in_buffer, "R0") == 0) {
953 printk(KERN_CRIT "Executing emergency reboot\n");
954 strcpy(remcom_out_buffer, "OK");
955 put_packet(remcom_out_buffer);
956
957 /*
958 * Execution should not return from
959 * machine_emergency_restart()
960 */
961 machine_emergency_restart();
962 kgdb_connected = 0;
963
964 return 1;
965 }
966 return 0;
967}
968
969/* Handle the 'q' query packets */
970static void gdb_cmd_query(struct kgdb_state *ks)
971{
972 struct task_struct *thread;
973 unsigned char thref[8];
974 char *ptr;
975 int i;
976
977 switch (remcom_in_buffer[1]) {
978 case 's':
979 case 'f':
980 if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) {
981 error_packet(remcom_out_buffer, -EINVAL);
982 break;
983 }
984
985 if (remcom_in_buffer[1] == 'f')
986 ks->threadid = 1;
987
988 remcom_out_buffer[0] = 'm';
989 ptr = remcom_out_buffer + 1;
990
991 for (i = 0; i < 17; ks->threadid++) {
992 thread = getthread(ks->linux_regs, ks->threadid);
993 if (thread) {
994 int_to_threadref(thref, ks->threadid);
995 pack_threadid(ptr, thref);
996 ptr += BUF_THREAD_ID_SIZE;
997 *(ptr++) = ',';
998 i++;
999 }
1000 }
1001 *(--ptr) = '\0';
1002 break;
1003
1004 case 'C':
1005 /* Current thread id */
1006 strcpy(remcom_out_buffer, "QC");
1007 ks->threadid = shadow_pid(current->pid);
1008 int_to_threadref(thref, ks->threadid);
1009 pack_threadid(remcom_out_buffer + 2, thref);
1010 break;
1011 case 'T':
1012 if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) {
1013 error_packet(remcom_out_buffer, -EINVAL);
1014 break;
1015 }
1016 ks->threadid = 0;
1017 ptr = remcom_in_buffer + 17;
1018 kgdb_hex2long(&ptr, &ks->threadid);
1019 if (!getthread(ks->linux_regs, ks->threadid)) {
1020 error_packet(remcom_out_buffer, -EINVAL);
1021 break;
1022 }
1023 if (ks->threadid > 0) {
1024 kgdb_mem2hex(getthread(ks->linux_regs,
1025 ks->threadid)->comm,
1026 remcom_out_buffer, 16);
1027 } else {
1028 static char tmpstr[23 + BUF_THREAD_ID_SIZE];
1029
1030 sprintf(tmpstr, "Shadow task %d for pid 0",
1031 (int)(-ks->threadid-1));
1032 kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
1033 }
1034 break;
1035 }
1036}
1037
1038/* Handle the 'H' task query packets */
1039static void gdb_cmd_task(struct kgdb_state *ks)
1040{
1041 struct task_struct *thread;
1042 char *ptr;
1043
1044 switch (remcom_in_buffer[1]) {
1045 case 'g':
1046 ptr = &remcom_in_buffer[2];
1047 kgdb_hex2long(&ptr, &ks->threadid);
1048 thread = getthread(ks->linux_regs, ks->threadid);
1049 if (!thread && ks->threadid > 0) {
1050 error_packet(remcom_out_buffer, -EINVAL);
1051 break;
1052 }
1053 kgdb_usethread = thread;
1054 ks->kgdb_usethreadid = ks->threadid;
1055 strcpy(remcom_out_buffer, "OK");
1056 break;
1057 case 'c':
1058 ptr = &remcom_in_buffer[2];
1059 kgdb_hex2long(&ptr, &ks->threadid);
1060 if (!ks->threadid) {
1061 kgdb_contthread = NULL;
1062 } else {
1063 thread = getthread(ks->linux_regs, ks->threadid);
1064 if (!thread && ks->threadid > 0) {
1065 error_packet(remcom_out_buffer, -EINVAL);
1066 break;
1067 }
1068 kgdb_contthread = thread;
1069 }
1070 strcpy(remcom_out_buffer, "OK");
1071 break;
1072 }
1073}
1074
1075/* Handle the 'T' thread query packets */
1076static void gdb_cmd_thread(struct kgdb_state *ks)
1077{
1078 char *ptr = &remcom_in_buffer[1];
1079 struct task_struct *thread;
1080
1081 kgdb_hex2long(&ptr, &ks->threadid);
1082 thread = getthread(ks->linux_regs, ks->threadid);
1083 if (thread)
1084 strcpy(remcom_out_buffer, "OK");
1085 else
1086 error_packet(remcom_out_buffer, -EINVAL);
1087}
1088
1089/* Handle the 'z' or 'Z' breakpoint remove or set packets */
1090static void gdb_cmd_break(struct kgdb_state *ks)
1091{
1092 /*
1093 * Since GDB-5.3, it's been drafted that '0' is a software
1094 * breakpoint, '1' is a hardware breakpoint, so let's do that.
1095 */
1096 char *bpt_type = &remcom_in_buffer[1];
1097 char *ptr = &remcom_in_buffer[2];
1098 unsigned long addr;
1099 unsigned long length;
1100 int error = 0;
1101
1102 if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
1103 /* Unsupported */
1104 if (*bpt_type > '4')
1105 return;
1106 } else {
1107 if (*bpt_type != '0' && *bpt_type != '1')
1108 /* Unsupported. */
1109 return;
1110 }
1111
1112 /*
1113 * Test if this is a hardware breakpoint, and
1114 * if we support it:
1115 */
1116 if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
1117 /* Unsupported. */
1118 return;
1119
1120 if (*(ptr++) != ',') {
1121 error_packet(remcom_out_buffer, -EINVAL);
1122 return;
1123 }
1124 if (!kgdb_hex2long(&ptr, &addr)) {
1125 error_packet(remcom_out_buffer, -EINVAL);
1126 return;
1127 }
1128 if (*(ptr++) != ',' ||
1129 !kgdb_hex2long(&ptr, &length)) {
1130 error_packet(remcom_out_buffer, -EINVAL);
1131 return;
1132 }
1133
1134 if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
1135 error = kgdb_set_sw_break(addr);
1136 else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
1137 error = kgdb_remove_sw_break(addr);
1138 else if (remcom_in_buffer[0] == 'Z')
1139 error = arch_kgdb_ops.set_hw_breakpoint(addr,
1140 (int)length, *bpt_type);
1141 else if (remcom_in_buffer[0] == 'z')
1142 error = arch_kgdb_ops.remove_hw_breakpoint(addr,
1143 (int) length, *bpt_type);
1144
1145 if (error == 0)
1146 strcpy(remcom_out_buffer, "OK");
1147 else
1148 error_packet(remcom_out_buffer, error);
1149}
1150
1151/* Handle the 'C' signal / exception passing packets */
1152static int gdb_cmd_exception_pass(struct kgdb_state *ks)
1153{
1154 /* C09 == pass exception
1155 * C15 == detach kgdb, pass exception
1156 */
1157 if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
1158
1159 ks->pass_exception = 1;
1160 remcom_in_buffer[0] = 'c';
1161
1162 } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
1163
1164 ks->pass_exception = 1;
1165 remcom_in_buffer[0] = 'D';
1166 remove_all_break();
1167 kgdb_connected = 0;
1168 return 1;
1169
1170 } else {
1171 error_packet(remcom_out_buffer, -EINVAL);
1172 return 0;
1173 }
1174
1175 /* Indicate fall through */
1176 return -1;
1177}
1178
1179/*
1180 * This function performs all gdbserial command procesing
1181 */
1182static int gdb_serial_stub(struct kgdb_state *ks)
1183{
1184 int error = 0;
1185 int tmp;
1186
1187 /* Clear the out buffer. */
1188 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
1189
1190 if (kgdb_connected) {
1191 unsigned char thref[8];
1192 char *ptr;
1193
1194 /* Reply to host that an exception has occurred */
1195 ptr = remcom_out_buffer;
1196 *ptr++ = 'T';
1197 ptr = pack_hex_byte(ptr, ks->signo);
1198 ptr += strlen(strcpy(ptr, "thread:"));
1199 int_to_threadref(thref, shadow_pid(current->pid));
1200 ptr = pack_threadid(ptr, thref);
1201 *ptr++ = ';';
1202 put_packet(remcom_out_buffer);
1203 }
1204
1205 kgdb_usethread = kgdb_info[ks->cpu].task;
1206 ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
1207 ks->pass_exception = 0;
1208
1209 while (1) {
1210 error = 0;
1211
1212 /* Clear the out buffer. */
1213 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
1214
1215 get_packet(remcom_in_buffer);
1216
1217 switch (remcom_in_buffer[0]) {
1218 case '?': /* gdbserial status */
1219 gdb_cmd_status(ks);
1220 break;
1221 case 'g': /* return the value of the CPU registers */
1222 gdb_cmd_getregs(ks);
1223 break;
1224 case 'G': /* set the value of the CPU registers - return OK */
1225 gdb_cmd_setregs(ks);
1226 break;
1227 case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */
1228 gdb_cmd_memread(ks);
1229 break;
1230 case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
1231 gdb_cmd_memwrite(ks);
1232 break;
1233 case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
1234 gdb_cmd_binwrite(ks);
1235 break;
1236 /* kill or detach. KGDB should treat this like a
1237 * continue.
1238 */
1239 case 'D': /* Debugger detach */
1240 case 'k': /* Debugger detach via kill */
1241 gdb_cmd_detachkill(ks);
1242 goto default_handle;
1243 case 'R': /* Reboot */
1244 if (gdb_cmd_reboot(ks))
1245 goto default_handle;
1246 break;
1247 case 'q': /* query command */
1248 gdb_cmd_query(ks);
1249 break;
1250 case 'H': /* task related */
1251 gdb_cmd_task(ks);
1252 break;
1253 case 'T': /* Query thread status */
1254 gdb_cmd_thread(ks);
1255 break;
1256 case 'z': /* Break point remove */
1257 case 'Z': /* Break point set */
1258 gdb_cmd_break(ks);
1259 break;
1260 case 'C': /* Exception passing */
1261 tmp = gdb_cmd_exception_pass(ks);
1262 if (tmp > 0)
1263 goto default_handle;
1264 if (tmp == 0)
1265 break;
1266 /* Fall through on tmp < 0 */
1267 case 'c': /* Continue packet */
1268 case 's': /* Single step packet */
1269 if (kgdb_contthread && kgdb_contthread != current) {
1270 /* Can't switch threads in kgdb */
1271 error_packet(remcom_out_buffer, -EINVAL);
1272 break;
1273 }
1274 kgdb_activate_sw_breakpoints();
1275 /* Fall through to default processing */
1276 default:
1277default_handle:
1278 error = kgdb_arch_handle_exception(ks->ex_vector,
1279 ks->signo,
1280 ks->err_code,
1281 remcom_in_buffer,
1282 remcom_out_buffer,
1283 ks->linux_regs);
1284 /*
1285 * Leave cmd processing on error, detach,
1286 * kill, continue, or single step.
1287 */
1288 if (error >= 0 || remcom_in_buffer[0] == 'D' ||
1289 remcom_in_buffer[0] == 'k') {
1290 error = 0;
1291 goto kgdb_exit;
1292 }
1293
1294 }
1295
1296 /* reply to the request */
1297 put_packet(remcom_out_buffer);
1298 }
1299
1300kgdb_exit:
1301 if (ks->pass_exception)
1302 error = 1;
1303 return error;
1304}
1305
1306static int kgdb_reenter_check(struct kgdb_state *ks)
1307{
1308 unsigned long addr;
1309
1310 if (atomic_read(&kgdb_active) != raw_smp_processor_id())
1311 return 0;
1312
1313 /* Panic on recursive debugger calls: */
1314 exception_level++;
1315 addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
1316 kgdb_deactivate_sw_breakpoints();
1317
1318 /*
1319 * If the break point removed ok at the place exception
1320 * occurred, try to recover and print a warning to the end
1321 * user because the user planted a breakpoint in a place that
1322 * KGDB needs in order to function.
1323 */
1324 if (kgdb_remove_sw_break(addr) == 0) {
1325 exception_level = 0;
1326 kgdb_skipexception(ks->ex_vector, ks->linux_regs);
1327 kgdb_activate_sw_breakpoints();
1328 printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed\n");
1329 WARN_ON_ONCE(1);
1330
1331 return 1;
1332 }
1333 remove_all_break();
1334 kgdb_skipexception(ks->ex_vector, ks->linux_regs);
1335
1336 if (exception_level > 1) {
1337 dump_stack();
1338 panic("Recursive entry to debugger");
1339 }
1340
1341 printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n");
1342 dump_stack();
1343 panic("Recursive entry to debugger");
1344
1345 return 1;
1346}
1347
1348/*
1349 * kgdb_handle_exception() - main entry point from a kernel exception
1350 *
1351 * Locking hierarchy:
1352 * interface locks, if any (begin_session)
1353 * kgdb lock (kgdb_active)
1354 */
1355int
1356kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
1357{
1358 struct kgdb_state kgdb_var;
1359 struct kgdb_state *ks = &kgdb_var;
1360 unsigned long flags;
1361 int error = 0;
1362 int i, cpu;
1363
1364 ks->cpu = raw_smp_processor_id();
1365 ks->ex_vector = evector;
1366 ks->signo = signo;
1367 ks->ex_vector = evector;
1368 ks->err_code = ecode;
1369 ks->kgdb_usethreadid = 0;
1370 ks->linux_regs = regs;
1371
1372 if (kgdb_reenter_check(ks))
1373 return 0; /* Ouch, double exception ! */
1374
1375acquirelock:
1376 /*
1377 * Interrupts will be restored by the 'trap return' code, except when
1378 * single stepping.
1379 */
1380 local_irq_save(flags);
1381
1382 cpu = raw_smp_processor_id();
1383
1384 /*
1385 * Acquire the kgdb_active lock:
1386 */
1387 while (atomic_cmpxchg(&kgdb_active, -1, cpu) != -1)
1388 cpu_relax();
1389
1390 /*
1391 * Do not start the debugger connection on this CPU if the last
1392 * instance of the exception handler wanted to come into the
1393 * debugger on a different CPU via a single step
1394 */
1395 if (atomic_read(&kgdb_cpu_doing_single_step) != -1 &&
1396 atomic_read(&kgdb_cpu_doing_single_step) != cpu) {
1397
1398 atomic_set(&kgdb_active, -1);
1399 local_irq_restore(flags);
1400
1401 goto acquirelock;
1402 }
1403
1404 if (!kgdb_io_ready(1)) {
1405 error = 1;
1406 goto kgdb_restore; /* No I/O connection, so resume the system */
1407 }
1408
1409 /*
1410 * Don't enter if we have hit a removed breakpoint.
1411 */
1412 if (kgdb_skipexception(ks->ex_vector, ks->linux_regs))
1413 goto kgdb_restore;
1414
1415 /* Call the I/O driver's pre_exception routine */
1416 if (kgdb_io_ops->pre_exception)
1417 kgdb_io_ops->pre_exception();
1418
1419 kgdb_info[ks->cpu].debuggerinfo = ks->linux_regs;
1420 kgdb_info[ks->cpu].task = current;
1421
1422 kgdb_disable_hw_debug(ks->linux_regs);
1423
1424 /*
1425 * Get the passive CPU lock which will hold all the non-primary
1426 * CPU in a spin state while the debugger is active
1427 */
1428 if (!kgdb_single_step || !kgdb_contthread) {
1429 for (i = 0; i < NR_CPUS; i++)
1430 atomic_set(&passive_cpu_wait[i], 1);
1431 }
1432
1433#ifdef CONFIG_SMP
1434 /* Signal the other CPUs to enter kgdb_wait() */
1435 if ((!kgdb_single_step || !kgdb_contthread) && kgdb_do_roundup)
1436 kgdb_roundup_cpus(flags);
1437#endif
1438
1439 /*
1440 * spin_lock code is good enough as a barrier so we don't
1441 * need one here:
1442 */
1443 atomic_set(&cpu_in_kgdb[ks->cpu], 1);
1444
1445 /*
1446 * Wait for the other CPUs to be notified and be waiting for us:
1447 */
1448 for_each_online_cpu(i) {
1449 while (!atomic_read(&cpu_in_kgdb[i]))
1450 cpu_relax();
1451 }
1452
1453 /*
1454 * At this point the primary processor is completely
1455 * in the debugger and all secondary CPUs are quiescent
1456 */
1457 kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code);
1458 kgdb_deactivate_sw_breakpoints();
1459 kgdb_single_step = 0;
1460 kgdb_contthread = NULL;
1461 exception_level = 0;
1462
1463 /* Talk to debugger with gdbserial protocol */
1464 error = gdb_serial_stub(ks);
1465
1466 /* Call the I/O driver's post_exception routine */
1467 if (kgdb_io_ops->post_exception)
1468 kgdb_io_ops->post_exception();
1469
1470 kgdb_info[ks->cpu].debuggerinfo = NULL;
1471 kgdb_info[ks->cpu].task = NULL;
1472 atomic_set(&cpu_in_kgdb[ks->cpu], 0);
1473
1474 if (!kgdb_single_step || !kgdb_contthread) {
1475 for (i = NR_CPUS-1; i >= 0; i--)
1476 atomic_set(&passive_cpu_wait[i], 0);
1477 /*
1478 * Wait till all the CPUs have quit
1479 * from the debugger.
1480 */
1481 for_each_online_cpu(i) {
1482 while (atomic_read(&cpu_in_kgdb[i]))
1483 cpu_relax();
1484 }
1485 }
1486
1487kgdb_restore:
1488 /* Free kgdb_active */
1489 atomic_set(&kgdb_active, -1);
1490 local_irq_restore(flags);
1491
1492 return error;
1493}
1494
1495int kgdb_nmicallback(int cpu, void *regs)
1496{
1497#ifdef CONFIG_SMP
1498 if (!atomic_read(&cpu_in_kgdb[cpu]) &&
1499 atomic_read(&kgdb_active) != cpu) {
1500 kgdb_wait((struct pt_regs *)regs);
1501 return 0;
1502 }
1503#endif
1504 return 1;
1505}
1506
1507void kgdb_console_write(struct console *co, const char *s, unsigned count)
1508{
1509 unsigned long flags;
1510
1511 /* If we're debugging, or KGDB has not connected, don't try
1512 * and print. */
1513 if (!kgdb_connected || atomic_read(&kgdb_active) != -1)
1514 return;
1515
1516 local_irq_save(flags);
1517 kgdb_msg_write(s, count);
1518 local_irq_restore(flags);
1519}
1520
1521static struct console kgdbcons = {
1522 .name = "kgdb",
1523 .write = kgdb_console_write,
1524 .flags = CON_PRINTBUFFER | CON_ENABLED,
1525 .index = -1,
1526};
1527
1528#ifdef CONFIG_MAGIC_SYSRQ
1529static void sysrq_handle_gdb(int key, struct tty_struct *tty)
1530{
1531 if (!kgdb_io_ops) {
1532 printk(KERN_CRIT "ERROR: No KGDB I/O module available\n");
1533 return;
1534 }
1535 if (!kgdb_connected)
1536 printk(KERN_CRIT "Entering KGDB\n");
1537
1538 kgdb_breakpoint();
1539}
1540
1541static struct sysrq_key_op sysrq_gdb_op = {
1542 .handler = sysrq_handle_gdb,
1543 .help_msg = "Gdb",
1544 .action_msg = "GDB",
1545};
1546#endif
1547
1548static void kgdb_register_callbacks(void)
1549{
1550 if (!kgdb_io_module_registered) {
1551 kgdb_io_module_registered = 1;
1552 kgdb_arch_init();
1553#ifdef CONFIG_MAGIC_SYSRQ
1554 register_sysrq_key('g', &sysrq_gdb_op);
1555#endif
1556 if (kgdb_use_con && !kgdb_con_registered) {
1557 register_console(&kgdbcons);
1558 kgdb_con_registered = 1;
1559 }
1560 }
1561}
1562
1563static void kgdb_unregister_callbacks(void)
1564{
1565 /*
1566 * When this routine is called KGDB should unregister from the
1567 * panic handler and clean up, making sure it is not handling any
1568 * break exceptions at the time.
1569 */
1570 if (kgdb_io_module_registered) {
1571 kgdb_io_module_registered = 0;
1572 kgdb_arch_exit();
1573#ifdef CONFIG_MAGIC_SYSRQ
1574 unregister_sysrq_key('g', &sysrq_gdb_op);
1575#endif
1576 if (kgdb_con_registered) {
1577 unregister_console(&kgdbcons);
1578 kgdb_con_registered = 0;
1579 }
1580 }
1581}
1582
1583static void kgdb_initial_breakpoint(void)
1584{
1585 kgdb_break_asap = 0;
1586
1587 printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n");
1588 kgdb_breakpoint();
1589}
1590
1591/**
1592 * kkgdb_register_io_module - register KGDB IO module
1593 * @new_kgdb_io_ops: the io ops vector
1594 *
1595 * Register it with the KGDB core.
1596 */
1597int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops)
1598{
1599 int err;
1600
1601 spin_lock(&kgdb_registration_lock);
1602
1603 if (kgdb_io_ops) {
1604 spin_unlock(&kgdb_registration_lock);
1605
1606 printk(KERN_ERR "kgdb: Another I/O driver is already "
1607 "registered with KGDB.\n");
1608 return -EBUSY;
1609 }
1610
1611 if (new_kgdb_io_ops->init) {
1612 err = new_kgdb_io_ops->init();
1613 if (err) {
1614 spin_unlock(&kgdb_registration_lock);
1615 return err;
1616 }
1617 }
1618
1619 kgdb_io_ops = new_kgdb_io_ops;
1620
1621 spin_unlock(&kgdb_registration_lock);
1622
1623 printk(KERN_INFO "kgdb: Registered I/O driver %s.\n",
1624 new_kgdb_io_ops->name);
1625
1626 /* Arm KGDB now. */
1627 kgdb_register_callbacks();
1628
1629 if (kgdb_break_asap)
1630 kgdb_initial_breakpoint();
1631
1632 return 0;
1633}
1634EXPORT_SYMBOL_GPL(kgdb_register_io_module);
1635
1636/**
1637 * kkgdb_unregister_io_module - unregister KGDB IO module
1638 * @old_kgdb_io_ops: the io ops vector
1639 *
1640 * Unregister it with the KGDB core.
1641 */
1642void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops)
1643{
1644 BUG_ON(kgdb_connected);
1645
1646 /*
1647 * KGDB is no longer able to communicate out, so
1648 * unregister our callbacks and reset state.
1649 */
1650 kgdb_unregister_callbacks();
1651
1652 spin_lock(&kgdb_registration_lock);
1653
1654 WARN_ON_ONCE(kgdb_io_ops != old_kgdb_io_ops);
1655 kgdb_io_ops = NULL;
1656
1657 spin_unlock(&kgdb_registration_lock);
1658
1659 printk(KERN_INFO
1660 "kgdb: Unregistered I/O driver %s, debugger disabled.\n",
1661 old_kgdb_io_ops->name);
1662}
1663EXPORT_SYMBOL_GPL(kgdb_unregister_io_module);
1664
1665/**
1666 * kgdb_breakpoint - generate breakpoint exception
1667 *
1668 * This function will generate a breakpoint exception. It is used at the
1669 * beginning of a program to sync up with a debugger and can be used
1670 * otherwise as a quick means to stop program execution and "break" into
1671 * the debugger.
1672 */
1673void kgdb_breakpoint(void)
1674{
1675 atomic_set(&kgdb_setting_breakpoint, 1);
1676 wmb(); /* Sync point before breakpoint */
1677 arch_kgdb_breakpoint();
1678 wmb(); /* Sync point after breakpoint */
1679 atomic_set(&kgdb_setting_breakpoint, 0);
1680}
1681EXPORT_SYMBOL_GPL(kgdb_breakpoint);
1682
1683static int __init opt_kgdb_wait(char *str)
1684{
1685 kgdb_break_asap = 1;
1686
1687 if (kgdb_io_module_registered)
1688 kgdb_initial_breakpoint();
1689
1690 return 0;
1691}
1692
1693early_param("kgdbwait", opt_kgdb_wait);
generated by cgit v1.2.2 (git 2.25.0) at 2024-12-24 05:10:53 -0500