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-rw-r--r--kernel/kgdb.c1764
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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#include <asm/unaligned.h>
56
57static int kgdb_break_asap;
58
59#define KGDB_MAX_THREAD_QUERY 17
60struct kgdb_state {
61 int ex_vector;
62 int signo;
63 int err_code;
64 int cpu;
65 int pass_exception;
66 unsigned long thr_query;
67 unsigned long threadid;
68 long kgdb_usethreadid;
69 struct pt_regs *linux_regs;
70};
71
72/* Exception state values */
73#define DCPU_WANT_MASTER 0x1 /* Waiting to become a master kgdb cpu */
74#define DCPU_NEXT_MASTER 0x2 /* Transition from one master cpu to another */
75#define DCPU_IS_SLAVE 0x4 /* Slave cpu enter exception */
76#define DCPU_SSTEP 0x8 /* CPU is single stepping */
77
78static struct debuggerinfo_struct {
79 void *debuggerinfo;
80 struct task_struct *task;
81 int exception_state;
82} kgdb_info[NR_CPUS];
83
84/**
85 * kgdb_connected - Is a host GDB connected to us?
86 */
87int kgdb_connected;
88EXPORT_SYMBOL_GPL(kgdb_connected);
89
90/* All the KGDB handlers are installed */
91static int kgdb_io_module_registered;
92
93/* Guard for recursive entry */
94static int exception_level;
95
96static struct kgdb_io *kgdb_io_ops;
97static DEFINE_SPINLOCK(kgdb_registration_lock);
98
99/* kgdb console driver is loaded */
100static int kgdb_con_registered;
101/* determine if kgdb console output should be used */
102static int kgdb_use_con;
103
104static int __init opt_kgdb_con(char *str)
105{
106 kgdb_use_con = 1;
107 return 0;
108}
109
110early_param("kgdbcon", opt_kgdb_con);
111
112module_param(kgdb_use_con, int, 0644);
113
114/*
115 * Holds information about breakpoints in a kernel. These breakpoints are
116 * added and removed by gdb.
117 */
118static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = {
119 [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED }
120};
121
122/*
123 * The CPU# of the active CPU, or -1 if none:
124 */
125atomic_t kgdb_active = ATOMIC_INIT(-1);
126
127/*
128 * We use NR_CPUs not PERCPU, in case kgdb is used to debug early
129 * bootup code (which might not have percpu set up yet):
130 */
131static atomic_t passive_cpu_wait[NR_CPUS];
132static atomic_t cpu_in_kgdb[NR_CPUS];
133atomic_t kgdb_setting_breakpoint;
134
135struct task_struct *kgdb_usethread;
136struct task_struct *kgdb_contthread;
137
138int kgdb_single_step;
139pid_t kgdb_sstep_pid;
140
141/* Our I/O buffers. */
142static char remcom_in_buffer[BUFMAX];
143static char remcom_out_buffer[BUFMAX];
144
145/* Storage for the registers, in GDB format. */
146static unsigned long gdb_regs[(NUMREGBYTES +
147 sizeof(unsigned long) - 1) /
148 sizeof(unsigned long)];
149
150/* to keep track of the CPU which is doing the single stepping*/
151atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1);
152
153/*
154 * If you are debugging a problem where roundup (the collection of
155 * all other CPUs) is a problem [this should be extremely rare],
156 * then use the nokgdbroundup option to avoid roundup. In that case
157 * the other CPUs might interfere with your debugging context, so
158 * use this with care:
159 */
160static int kgdb_do_roundup = 1;
161
162static int __init opt_nokgdbroundup(char *str)
163{
164 kgdb_do_roundup = 0;
165
166 return 0;
167}
168
169early_param("nokgdbroundup", opt_nokgdbroundup);
170
171/*
172 * Finally, some KGDB code :-)
173 */
174
175/*
176 * Weak aliases for breakpoint management,
177 * can be overriden by architectures when needed:
178 */
179int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
180{
181 int err;
182
183 err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE);
184 if (err)
185 return err;
186
187 return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr,
188 BREAK_INSTR_SIZE);
189}
190
191int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle)
192{
193 return probe_kernel_write((char *)addr,
194 (char *)bundle, BREAK_INSTR_SIZE);
195}
196
197int __weak kgdb_validate_break_address(unsigned long addr)
198{
199 char tmp_variable[BREAK_INSTR_SIZE];
200 int err;
201 /* Validate setting the breakpoint and then removing it. In the
202 * remove fails, the kernel needs to emit a bad message because we
203 * are deep trouble not being able to put things back the way we
204 * found them.
205 */
206 err = kgdb_arch_set_breakpoint(addr, tmp_variable);
207 if (err)
208 return err;
209 err = kgdb_arch_remove_breakpoint(addr, tmp_variable);
210 if (err)
211 printk(KERN_ERR "KGDB: Critical breakpoint error, kernel "
212 "memory destroyed at: %lx", addr);
213 return err;
214}
215
216unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs)
217{
218 return instruction_pointer(regs);
219}
220
221int __weak kgdb_arch_init(void)
222{
223 return 0;
224}
225
226int __weak kgdb_skipexception(int exception, struct pt_regs *regs)
227{
228 return 0;
229}
230
231void __weak
232kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code)
233{
234 return;
235}
236
237/**
238 * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
239 * @regs: Current &struct pt_regs.
240 *
241 * This function will be called if the particular architecture must
242 * disable hardware debugging while it is processing gdb packets or
243 * handling exception.
244 */
245void __weak kgdb_disable_hw_debug(struct pt_regs *regs)
246{
247}
248
249/*
250 * GDB remote protocol parser:
251 */
252
253static int hex(char ch)
254{
255 if ((ch >= 'a') && (ch <= 'f'))
256 return ch - 'a' + 10;
257 if ((ch >= '0') && (ch <= '9'))
258 return ch - '0';
259 if ((ch >= 'A') && (ch <= 'F'))
260 return ch - 'A' + 10;
261 return -1;
262}
263
264/* scan for the sequence $<data>#<checksum> */
265static void get_packet(char *buffer)
266{
267 unsigned char checksum;
268 unsigned char xmitcsum;
269 int count;
270 char ch;
271
272 do {
273 /*
274 * Spin and wait around for the start character, ignore all
275 * other characters:
276 */
277 while ((ch = (kgdb_io_ops->read_char())) != '$')
278 /* nothing */;
279
280 kgdb_connected = 1;
281 checksum = 0;
282 xmitcsum = -1;
283
284 count = 0;
285
286 /*
287 * now, read until a # or end of buffer is found:
288 */
289 while (count < (BUFMAX - 1)) {
290 ch = kgdb_io_ops->read_char();
291 if (ch == '#')
292 break;
293 checksum = checksum + ch;
294 buffer[count] = ch;
295 count = count + 1;
296 }
297 buffer[count] = 0;
298
299 if (ch == '#') {
300 xmitcsum = hex(kgdb_io_ops->read_char()) << 4;
301 xmitcsum += hex(kgdb_io_ops->read_char());
302
303 if (checksum != xmitcsum)
304 /* failed checksum */
305 kgdb_io_ops->write_char('-');
306 else
307 /* successful transfer */
308 kgdb_io_ops->write_char('+');
309 if (kgdb_io_ops->flush)
310 kgdb_io_ops->flush();
311 }
312 } while (checksum != xmitcsum);
313}
314
315/*
316 * Send the packet in buffer.
317 * Check for gdb connection if asked for.
318 */
319static void put_packet(char *buffer)
320{
321 unsigned char checksum;
322 int count;
323 char ch;
324
325 /*
326 * $<packet info>#<checksum>.
327 */
328 while (1) {
329 kgdb_io_ops->write_char('$');
330 checksum = 0;
331 count = 0;
332
333 while ((ch = buffer[count])) {
334 kgdb_io_ops->write_char(ch);
335 checksum += ch;
336 count++;
337 }
338
339 kgdb_io_ops->write_char('#');
340 kgdb_io_ops->write_char(hex_asc_hi(checksum));
341 kgdb_io_ops->write_char(hex_asc_lo(checksum));
342 if (kgdb_io_ops->flush)
343 kgdb_io_ops->flush();
344
345 /* Now see what we get in reply. */
346 ch = kgdb_io_ops->read_char();
347
348 if (ch == 3)
349 ch = kgdb_io_ops->read_char();
350
351 /* If we get an ACK, we are done. */
352 if (ch == '+')
353 return;
354
355 /*
356 * If we get the start of another packet, this means
357 * that GDB is attempting to reconnect. We will NAK
358 * the packet being sent, and stop trying to send this
359 * packet.
360 */
361 if (ch == '$') {
362 kgdb_io_ops->write_char('-');
363 if (kgdb_io_ops->flush)
364 kgdb_io_ops->flush();
365 return;
366 }
367 }
368}
369
370/*
371 * Convert the memory pointed to by mem into hex, placing result in buf.
372 * Return a pointer to the last char put in buf (null). May return an error.
373 */
374int kgdb_mem2hex(char *mem, char *buf, int count)
375{
376 char *tmp;
377 int err;
378
379 /*
380 * We use the upper half of buf as an intermediate buffer for the
381 * raw memory copy. Hex conversion will work against this one.
382 */
383 tmp = buf + count;
384
385 err = probe_kernel_read(tmp, mem, count);
386 if (!err) {
387 while (count > 0) {
388 buf = pack_hex_byte(buf, *tmp);
389 tmp++;
390 count--;
391 }
392
393 *buf = 0;
394 }
395
396 return err;
397}
398
399/*
400 * Copy the binary array pointed to by buf into mem. Fix $, #, and
401 * 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success.
402 * The input buf is overwitten with the result to write to mem.
403 */
404static int kgdb_ebin2mem(char *buf, char *mem, int count)
405{
406 int size = 0;
407 char *c = buf;
408
409 while (count-- > 0) {
410 c[size] = *buf++;
411 if (c[size] == 0x7d)
412 c[size] = *buf++ ^ 0x20;
413 size++;
414 }
415
416 return probe_kernel_write(mem, c, size);
417}
418
419/*
420 * Convert the hex array pointed to by buf into binary to be placed in mem.
421 * Return a pointer to the character AFTER the last byte written.
422 * May return an error.
423 */
424int kgdb_hex2mem(char *buf, char *mem, int count)
425{
426 char *tmp_raw;
427 char *tmp_hex;
428
429 /*
430 * We use the upper half of buf as an intermediate buffer for the
431 * raw memory that is converted from hex.
432 */
433 tmp_raw = buf + count * 2;
434
435 tmp_hex = tmp_raw - 1;
436 while (tmp_hex >= buf) {
437 tmp_raw--;
438 *tmp_raw = hex(*tmp_hex--);
439 *tmp_raw |= hex(*tmp_hex--) << 4;
440 }
441
442 return probe_kernel_write(mem, tmp_raw, count);
443}
444
445/*
446 * While we find nice hex chars, build a long_val.
447 * Return number of chars processed.
448 */
449int kgdb_hex2long(char **ptr, unsigned long *long_val)
450{
451 int hex_val;
452 int num = 0;
453 int negate = 0;
454
455 *long_val = 0;
456
457 if (**ptr == '-') {
458 negate = 1;
459 (*ptr)++;
460 }
461 while (**ptr) {
462 hex_val = hex(**ptr);
463 if (hex_val < 0)
464 break;
465
466 *long_val = (*long_val << 4) | hex_val;
467 num++;
468 (*ptr)++;
469 }
470
471 if (negate)
472 *long_val = -*long_val;
473
474 return num;
475}
476
477/* Write memory due to an 'M' or 'X' packet. */
478static int write_mem_msg(int binary)
479{
480 char *ptr = &remcom_in_buffer[1];
481 unsigned long addr;
482 unsigned long length;
483 int err;
484
485 if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
486 kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
487 if (binary)
488 err = kgdb_ebin2mem(ptr, (char *)addr, length);
489 else
490 err = kgdb_hex2mem(ptr, (char *)addr, length);
491 if (err)
492 return err;
493 if (CACHE_FLUSH_IS_SAFE)
494 flush_icache_range(addr, addr + length);
495 return 0;
496 }
497
498 return -EINVAL;
499}
500
501static void error_packet(char *pkt, int error)
502{
503 error = -error;
504 pkt[0] = 'E';
505 pkt[1] = hex_asc[(error / 10)];
506 pkt[2] = hex_asc[(error % 10)];
507 pkt[3] = '\0';
508}
509
510/*
511 * Thread ID accessors. We represent a flat TID space to GDB, where
512 * the per CPU idle threads (which under Linux all have PID 0) are
513 * remapped to negative TIDs.
514 */
515
516#define BUF_THREAD_ID_SIZE 16
517
518static char *pack_threadid(char *pkt, unsigned char *id)
519{
520 char *limit;
521
522 limit = pkt + BUF_THREAD_ID_SIZE;
523 while (pkt < limit)
524 pkt = pack_hex_byte(pkt, *id++);
525
526 return pkt;
527}
528
529static void int_to_threadref(unsigned char *id, int value)
530{
531 unsigned char *scan;
532 int i = 4;
533
534 scan = (unsigned char *)id;
535 while (i--)
536 *scan++ = 0;
537 put_unaligned_be32(value, scan);
538}
539
540static struct task_struct *getthread(struct pt_regs *regs, int tid)
541{
542 /*
543 * Non-positive TIDs are remapped to the cpu shadow information
544 */
545 if (tid == 0 || tid == -1)
546 tid = -atomic_read(&kgdb_active) - 2;
547 if (tid < -1 && tid > -NR_CPUS - 2) {
548 if (kgdb_info[-tid - 2].task)
549 return kgdb_info[-tid - 2].task;
550 else
551 return idle_task(-tid - 2);
552 }
553 if (tid <= 0) {
554 printk(KERN_ERR "KGDB: Internal thread select error\n");
555 dump_stack();
556 return NULL;
557 }
558
559 /*
560 * find_task_by_pid_ns() does not take the tasklist lock anymore
561 * but is nicely RCU locked - hence is a pretty resilient
562 * thing to use:
563 */
564 return find_task_by_pid_ns(tid, &init_pid_ns);
565}
566
567/*
568 * Some architectures need cache flushes when we set/clear a
569 * breakpoint:
570 */
571static void kgdb_flush_swbreak_addr(unsigned long addr)
572{
573 if (!CACHE_FLUSH_IS_SAFE)
574 return;
575
576 if (current->mm && current->mm->mmap_cache) {
577 flush_cache_range(current->mm->mmap_cache,
578 addr, addr + BREAK_INSTR_SIZE);
579 }
580 /* Force flush instruction cache if it was outside the mm */
581 flush_icache_range(addr, addr + BREAK_INSTR_SIZE);
582}
583
584/*
585 * SW breakpoint management:
586 */
587static int kgdb_activate_sw_breakpoints(void)
588{
589 unsigned long addr;
590 int error;
591 int ret = 0;
592 int i;
593
594 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
595 if (kgdb_break[i].state != BP_SET)
596 continue;
597
598 addr = kgdb_break[i].bpt_addr;
599 error = kgdb_arch_set_breakpoint(addr,
600 kgdb_break[i].saved_instr);
601 if (error) {
602 ret = error;
603 printk(KERN_INFO "KGDB: BP install failed: %lx", addr);
604 continue;
605 }
606
607 kgdb_flush_swbreak_addr(addr);
608 kgdb_break[i].state = BP_ACTIVE;
609 }
610 return ret;
611}
612
613static int kgdb_set_sw_break(unsigned long addr)
614{
615 int err = kgdb_validate_break_address(addr);
616 int breakno = -1;
617 int i;
618
619 if (err)
620 return err;
621
622 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
623 if ((kgdb_break[i].state == BP_SET) &&
624 (kgdb_break[i].bpt_addr == addr))
625 return -EEXIST;
626 }
627 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
628 if (kgdb_break[i].state == BP_REMOVED &&
629 kgdb_break[i].bpt_addr == addr) {
630 breakno = i;
631 break;
632 }
633 }
634
635 if (breakno == -1) {
636 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
637 if (kgdb_break[i].state == BP_UNDEFINED) {
638 breakno = i;
639 break;
640 }
641 }
642 }
643
644 if (breakno == -1)
645 return -E2BIG;
646
647 kgdb_break[breakno].state = BP_SET;
648 kgdb_break[breakno].type = BP_BREAKPOINT;
649 kgdb_break[breakno].bpt_addr = addr;
650
651 return 0;
652}
653
654static int kgdb_deactivate_sw_breakpoints(void)
655{
656 unsigned long addr;
657 int error;
658 int ret = 0;
659 int i;
660
661 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
662 if (kgdb_break[i].state != BP_ACTIVE)
663 continue;
664 addr = kgdb_break[i].bpt_addr;
665 error = kgdb_arch_remove_breakpoint(addr,
666 kgdb_break[i].saved_instr);
667 if (error) {
668 printk(KERN_INFO "KGDB: BP remove failed: %lx\n", addr);
669 ret = error;
670 }
671
672 kgdb_flush_swbreak_addr(addr);
673 kgdb_break[i].state = BP_SET;
674 }
675 return ret;
676}
677
678static int kgdb_remove_sw_break(unsigned long addr)
679{
680 int i;
681
682 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
683 if ((kgdb_break[i].state == BP_SET) &&
684 (kgdb_break[i].bpt_addr == addr)) {
685 kgdb_break[i].state = BP_REMOVED;
686 return 0;
687 }
688 }
689 return -ENOENT;
690}
691
692int kgdb_isremovedbreak(unsigned long addr)
693{
694 int i;
695
696 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
697 if ((kgdb_break[i].state == BP_REMOVED) &&
698 (kgdb_break[i].bpt_addr == addr))
699 return 1;
700 }
701 return 0;
702}
703
704static int remove_all_break(void)
705{
706 unsigned long addr;
707 int error;
708 int i;
709
710 /* Clear memory breakpoints. */
711 for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
712 if (kgdb_break[i].state != BP_ACTIVE)
713 goto setundefined;
714 addr = kgdb_break[i].bpt_addr;
715 error = kgdb_arch_remove_breakpoint(addr,
716 kgdb_break[i].saved_instr);
717 if (error)
718 printk(KERN_ERR "KGDB: breakpoint remove failed: %lx\n",
719 addr);
720setundefined:
721 kgdb_break[i].state = BP_UNDEFINED;
722 }
723
724 /* Clear hardware breakpoints. */
725 if (arch_kgdb_ops.remove_all_hw_break)
726 arch_kgdb_ops.remove_all_hw_break();
727
728 return 0;
729}
730
731/*
732 * Remap normal tasks to their real PID,
733 * CPU shadow threads are mapped to -CPU - 2
734 */
735static inline int shadow_pid(int realpid)
736{
737 if (realpid)
738 return realpid;
739
740 return -raw_smp_processor_id() - 2;
741}
742
743static char gdbmsgbuf[BUFMAX + 1];
744
745static void kgdb_msg_write(const char *s, int len)
746{
747 char *bufptr;
748 int wcount;
749 int i;
750
751 /* 'O'utput */
752 gdbmsgbuf[0] = 'O';
753
754 /* Fill and send buffers... */
755 while (len > 0) {
756 bufptr = gdbmsgbuf + 1;
757
758 /* Calculate how many this time */
759 if ((len << 1) > (BUFMAX - 2))
760 wcount = (BUFMAX - 2) >> 1;
761 else
762 wcount = len;
763
764 /* Pack in hex chars */
765 for (i = 0; i < wcount; i++)
766 bufptr = pack_hex_byte(bufptr, s[i]);
767 *bufptr = '\0';
768
769 /* Move up */
770 s += wcount;
771 len -= wcount;
772
773 /* Write packet */
774 put_packet(gdbmsgbuf);
775 }
776}
777
778/*
779 * Return true if there is a valid kgdb I/O module. Also if no
780 * debugger is attached a message can be printed to the console about
781 * waiting for the debugger to attach.
782 *
783 * The print_wait argument is only to be true when called from inside
784 * the core kgdb_handle_exception, because it will wait for the
785 * debugger to attach.
786 */
787static int kgdb_io_ready(int print_wait)
788{
789 if (!kgdb_io_ops)
790 return 0;
791 if (kgdb_connected)
792 return 1;
793 if (atomic_read(&kgdb_setting_breakpoint))
794 return 1;
795 if (print_wait)
796 printk(KERN_CRIT "KGDB: Waiting for remote debugger\n");
797 return 1;
798}
799
800/*
801 * All the functions that start with gdb_cmd are the various
802 * operations to implement the handlers for the gdbserial protocol
803 * where KGDB is communicating with an external debugger
804 */
805
806/* Handle the '?' status packets */
807static void gdb_cmd_status(struct kgdb_state *ks)
808{
809 /*
810 * We know that this packet is only sent
811 * during initial connect. So to be safe,
812 * we clear out our breakpoints now in case
813 * GDB is reconnecting.
814 */
815 remove_all_break();
816
817 remcom_out_buffer[0] = 'S';
818 pack_hex_byte(&remcom_out_buffer[1], ks->signo);
819}
820
821/* Handle the 'g' get registers request */
822static void gdb_cmd_getregs(struct kgdb_state *ks)
823{
824 struct task_struct *thread;
825 void *local_debuggerinfo;
826 int i;
827
828 thread = kgdb_usethread;
829 if (!thread) {
830 thread = kgdb_info[ks->cpu].task;
831 local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
832 } else {
833 local_debuggerinfo = NULL;
834 for_each_online_cpu(i) {
835 /*
836 * Try to find the task on some other
837 * or possibly this node if we do not
838 * find the matching task then we try
839 * to approximate the results.
840 */
841 if (thread == kgdb_info[i].task)
842 local_debuggerinfo = kgdb_info[i].debuggerinfo;
843 }
844 }
845
846 /*
847 * All threads that don't have debuggerinfo should be
848 * in schedule() sleeping, since all other CPUs
849 * are in kgdb_wait, and thus have debuggerinfo.
850 */
851 if (local_debuggerinfo) {
852 pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
853 } else {
854 /*
855 * Pull stuff saved during switch_to; nothing
856 * else is accessible (or even particularly
857 * relevant).
858 *
859 * This should be enough for a stack trace.
860 */
861 sleeping_thread_to_gdb_regs(gdb_regs, thread);
862 }
863 kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
864}
865
866/* Handle the 'G' set registers request */
867static void gdb_cmd_setregs(struct kgdb_state *ks)
868{
869 kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
870
871 if (kgdb_usethread && kgdb_usethread != current) {
872 error_packet(remcom_out_buffer, -EINVAL);
873 } else {
874 gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
875 strcpy(remcom_out_buffer, "OK");
876 }
877}
878
879/* Handle the 'm' memory read bytes */
880static void gdb_cmd_memread(struct kgdb_state *ks)
881{
882 char *ptr = &remcom_in_buffer[1];
883 unsigned long length;
884 unsigned long addr;
885 int err;
886
887 if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
888 kgdb_hex2long(&ptr, &length) > 0) {
889 err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
890 if (err)
891 error_packet(remcom_out_buffer, err);
892 } else {
893 error_packet(remcom_out_buffer, -EINVAL);
894 }
895}
896
897/* Handle the 'M' memory write bytes */
898static void gdb_cmd_memwrite(struct kgdb_state *ks)
899{
900 int err = write_mem_msg(0);
901
902 if (err)
903 error_packet(remcom_out_buffer, err);
904 else
905 strcpy(remcom_out_buffer, "OK");
906}
907
908/* Handle the 'X' memory binary write bytes */
909static void gdb_cmd_binwrite(struct kgdb_state *ks)
910{
911 int err = write_mem_msg(1);
912
913 if (err)
914 error_packet(remcom_out_buffer, err);
915 else
916 strcpy(remcom_out_buffer, "OK");
917}
918
919/* Handle the 'D' or 'k', detach or kill packets */
920static void gdb_cmd_detachkill(struct kgdb_state *ks)
921{
922 int error;
923
924 /* The detach case */
925 if (remcom_in_buffer[0] == 'D') {
926 error = remove_all_break();
927 if (error < 0) {
928 error_packet(remcom_out_buffer, error);
929 } else {
930 strcpy(remcom_out_buffer, "OK");
931 kgdb_connected = 0;
932 }
933 put_packet(remcom_out_buffer);
934 } else {
935 /*
936 * Assume the kill case, with no exit code checking,
937 * trying to force detach the debugger:
938 */
939 remove_all_break();
940 kgdb_connected = 0;
941 }
942}
943
944/* Handle the 'R' reboot packets */
945static int gdb_cmd_reboot(struct kgdb_state *ks)
946{
947 /* For now, only honor R0 */
948 if (strcmp(remcom_in_buffer, "R0") == 0) {
949 printk(KERN_CRIT "Executing emergency reboot\n");
950 strcpy(remcom_out_buffer, "OK");
951 put_packet(remcom_out_buffer);
952
953 /*
954 * Execution should not return from
955 * machine_emergency_restart()
956 */
957 machine_emergency_restart();
958 kgdb_connected = 0;
959
960 return 1;
961 }
962 return 0;
963}
964
965/* Handle the 'q' query packets */
966static void gdb_cmd_query(struct kgdb_state *ks)
967{
968 struct task_struct *g;
969 struct task_struct *p;
970 unsigned char thref[8];
971 char *ptr;
972 int i;
973 int cpu;
974 int finished = 0;
975
976 switch (remcom_in_buffer[1]) {
977 case 's':
978 case 'f':
979 if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) {
980 error_packet(remcom_out_buffer, -EINVAL);
981 break;
982 }
983
984 i = 0;
985 remcom_out_buffer[0] = 'm';
986 ptr = remcom_out_buffer + 1;
987 if (remcom_in_buffer[1] == 'f') {
988 /* Each cpu is a shadow thread */
989 for_each_online_cpu(cpu) {
990 ks->thr_query = 0;
991 int_to_threadref(thref, -cpu - 2);
992 pack_threadid(ptr, thref);
993 ptr += BUF_THREAD_ID_SIZE;
994 *(ptr++) = ',';
995 i++;
996 }
997 }
998
999 do_each_thread(g, p) {
1000 if (i >= ks->thr_query && !finished) {
1001 int_to_threadref(thref, p->pid);
1002 pack_threadid(ptr, thref);
1003 ptr += BUF_THREAD_ID_SIZE;
1004 *(ptr++) = ',';
1005 ks->thr_query++;
1006 if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0)
1007 finished = 1;
1008 }
1009 i++;
1010 } while_each_thread(g, p);
1011
1012 *(--ptr) = '\0';
1013 break;
1014
1015 case 'C':
1016 /* Current thread id */
1017 strcpy(remcom_out_buffer, "QC");
1018 ks->threadid = shadow_pid(current->pid);
1019 int_to_threadref(thref, ks->threadid);
1020 pack_threadid(remcom_out_buffer + 2, thref);
1021 break;
1022 case 'T':
1023 if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) {
1024 error_packet(remcom_out_buffer, -EINVAL);
1025 break;
1026 }
1027 ks->threadid = 0;
1028 ptr = remcom_in_buffer + 17;
1029 kgdb_hex2long(&ptr, &ks->threadid);
1030 if (!getthread(ks->linux_regs, ks->threadid)) {
1031 error_packet(remcom_out_buffer, -EINVAL);
1032 break;
1033 }
1034 if ((int)ks->threadid > 0) {
1035 kgdb_mem2hex(getthread(ks->linux_regs,
1036 ks->threadid)->comm,
1037 remcom_out_buffer, 16);
1038 } else {
1039 static char tmpstr[23 + BUF_THREAD_ID_SIZE];
1040
1041 sprintf(tmpstr, "shadowCPU%d",
1042 (int)(-ks->threadid - 2));
1043 kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
1044 }
1045 break;
1046 }
1047}
1048
1049/* Handle the 'H' task query packets */
1050static void gdb_cmd_task(struct kgdb_state *ks)
1051{
1052 struct task_struct *thread;
1053 char *ptr;
1054
1055 switch (remcom_in_buffer[1]) {
1056 case 'g':
1057 ptr = &remcom_in_buffer[2];
1058 kgdb_hex2long(&ptr, &ks->threadid);
1059 thread = getthread(ks->linux_regs, ks->threadid);
1060 if (!thread && ks->threadid > 0) {
1061 error_packet(remcom_out_buffer, -EINVAL);
1062 break;
1063 }
1064 kgdb_usethread = thread;
1065 ks->kgdb_usethreadid = ks->threadid;
1066 strcpy(remcom_out_buffer, "OK");
1067 break;
1068 case 'c':
1069 ptr = &remcom_in_buffer[2];
1070 kgdb_hex2long(&ptr, &ks->threadid);
1071 if (!ks->threadid) {
1072 kgdb_contthread = NULL;
1073 } else {
1074 thread = getthread(ks->linux_regs, ks->threadid);
1075 if (!thread && ks->threadid > 0) {
1076 error_packet(remcom_out_buffer, -EINVAL);
1077 break;
1078 }
1079 kgdb_contthread = thread;
1080 }
1081 strcpy(remcom_out_buffer, "OK");
1082 break;
1083 }
1084}
1085
1086/* Handle the 'T' thread query packets */
1087static void gdb_cmd_thread(struct kgdb_state *ks)
1088{
1089 char *ptr = &remcom_in_buffer[1];
1090 struct task_struct *thread;
1091
1092 kgdb_hex2long(&ptr, &ks->threadid);
1093 thread = getthread(ks->linux_regs, ks->threadid);
1094 if (thread)
1095 strcpy(remcom_out_buffer, "OK");
1096 else
1097 error_packet(remcom_out_buffer, -EINVAL);
1098}
1099
1100/* Handle the 'z' or 'Z' breakpoint remove or set packets */
1101static void gdb_cmd_break(struct kgdb_state *ks)
1102{
1103 /*
1104 * Since GDB-5.3, it's been drafted that '0' is a software
1105 * breakpoint, '1' is a hardware breakpoint, so let's do that.
1106 */
1107 char *bpt_type = &remcom_in_buffer[1];
1108 char *ptr = &remcom_in_buffer[2];
1109 unsigned long addr;
1110 unsigned long length;
1111 int error = 0;
1112
1113 if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
1114 /* Unsupported */
1115 if (*bpt_type > '4')
1116 return;
1117 } else {
1118 if (*bpt_type != '0' && *bpt_type != '1')
1119 /* Unsupported. */
1120 return;
1121 }
1122
1123 /*
1124 * Test if this is a hardware breakpoint, and
1125 * if we support it:
1126 */
1127 if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
1128 /* Unsupported. */
1129 return;
1130
1131 if (*(ptr++) != ',') {
1132 error_packet(remcom_out_buffer, -EINVAL);
1133 return;
1134 }
1135 if (!kgdb_hex2long(&ptr, &addr)) {
1136 error_packet(remcom_out_buffer, -EINVAL);
1137 return;
1138 }
1139 if (*(ptr++) != ',' ||
1140 !kgdb_hex2long(&ptr, &length)) {
1141 error_packet(remcom_out_buffer, -EINVAL);
1142 return;
1143 }
1144
1145 if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
1146 error = kgdb_set_sw_break(addr);
1147 else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
1148 error = kgdb_remove_sw_break(addr);
1149 else if (remcom_in_buffer[0] == 'Z')
1150 error = arch_kgdb_ops.set_hw_breakpoint(addr,
1151 (int)length, *bpt_type - '0');
1152 else if (remcom_in_buffer[0] == 'z')
1153 error = arch_kgdb_ops.remove_hw_breakpoint(addr,
1154 (int) length, *bpt_type - '0');
1155
1156 if (error == 0)
1157 strcpy(remcom_out_buffer, "OK");
1158 else
1159 error_packet(remcom_out_buffer, error);
1160}
1161
1162/* Handle the 'C' signal / exception passing packets */
1163static int gdb_cmd_exception_pass(struct kgdb_state *ks)
1164{
1165 /* C09 == pass exception
1166 * C15 == detach kgdb, pass exception
1167 */
1168 if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
1169
1170 ks->pass_exception = 1;
1171 remcom_in_buffer[0] = 'c';
1172
1173 } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
1174
1175 ks->pass_exception = 1;
1176 remcom_in_buffer[0] = 'D';
1177 remove_all_break();
1178 kgdb_connected = 0;
1179 return 1;
1180
1181 } else {
1182 kgdb_msg_write("KGDB only knows signal 9 (pass)"
1183 " and 15 (pass and disconnect)\n"
1184 "Executing a continue without signal passing\n", 0);
1185 remcom_in_buffer[0] = 'c';
1186 }
1187
1188 /* Indicate fall through */
1189 return -1;
1190}
1191
1192/*
1193 * This function performs all gdbserial command procesing
1194 */
1195static int gdb_serial_stub(struct kgdb_state *ks)
1196{
1197 int error = 0;
1198 int tmp;
1199
1200 /* Clear the out buffer. */
1201 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
1202
1203 if (kgdb_connected) {
1204 unsigned char thref[8];
1205 char *ptr;
1206
1207 /* Reply to host that an exception has occurred */
1208 ptr = remcom_out_buffer;
1209 *ptr++ = 'T';
1210 ptr = pack_hex_byte(ptr, ks->signo);
1211 ptr += strlen(strcpy(ptr, "thread:"));
1212 int_to_threadref(thref, shadow_pid(current->pid));
1213 ptr = pack_threadid(ptr, thref);
1214 *ptr++ = ';';
1215 put_packet(remcom_out_buffer);
1216 }
1217
1218 kgdb_usethread = kgdb_info[ks->cpu].task;
1219 ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
1220 ks->pass_exception = 0;
1221
1222 while (1) {
1223 error = 0;
1224
1225 /* Clear the out buffer. */
1226 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
1227
1228 get_packet(remcom_in_buffer);
1229
1230 switch (remcom_in_buffer[0]) {
1231 case '?': /* gdbserial status */
1232 gdb_cmd_status(ks);
1233 break;
1234 case 'g': /* return the value of the CPU registers */
1235 gdb_cmd_getregs(ks);
1236 break;
1237 case 'G': /* set the value of the CPU registers - return OK */
1238 gdb_cmd_setregs(ks);
1239 break;
1240 case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */
1241 gdb_cmd_memread(ks);
1242 break;
1243 case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
1244 gdb_cmd_memwrite(ks);
1245 break;
1246 case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
1247 gdb_cmd_binwrite(ks);
1248 break;
1249 /* kill or detach. KGDB should treat this like a
1250 * continue.
1251 */
1252 case 'D': /* Debugger detach */
1253 case 'k': /* Debugger detach via kill */
1254 gdb_cmd_detachkill(ks);
1255 goto default_handle;
1256 case 'R': /* Reboot */
1257 if (gdb_cmd_reboot(ks))
1258 goto default_handle;
1259 break;
1260 case 'q': /* query command */
1261 gdb_cmd_query(ks);
1262 break;
1263 case 'H': /* task related */
1264 gdb_cmd_task(ks);
1265 break;
1266 case 'T': /* Query thread status */
1267 gdb_cmd_thread(ks);
1268 break;
1269 case 'z': /* Break point remove */
1270 case 'Z': /* Break point set */
1271 gdb_cmd_break(ks);
1272 break;
1273 case 'C': /* Exception passing */
1274 tmp = gdb_cmd_exception_pass(ks);
1275 if (tmp > 0)
1276 goto default_handle;
1277 if (tmp == 0)
1278 break;
1279 /* Fall through on tmp < 0 */
1280 case 'c': /* Continue packet */
1281 case 's': /* Single step packet */
1282 if (kgdb_contthread && kgdb_contthread != current) {
1283 /* Can't switch threads in kgdb */
1284 error_packet(remcom_out_buffer, -EINVAL);
1285 break;
1286 }
1287 kgdb_activate_sw_breakpoints();
1288 /* Fall through to default processing */
1289 default:
1290default_handle:
1291 error = kgdb_arch_handle_exception(ks->ex_vector,
1292 ks->signo,
1293 ks->err_code,
1294 remcom_in_buffer,
1295 remcom_out_buffer,
1296 ks->linux_regs);
1297 /*
1298 * Leave cmd processing on error, detach,
1299 * kill, continue, or single step.
1300 */
1301 if (error >= 0 || remcom_in_buffer[0] == 'D' ||
1302 remcom_in_buffer[0] == 'k') {
1303 error = 0;
1304 goto kgdb_exit;
1305 }
1306
1307 }
1308
1309 /* reply to the request */
1310 put_packet(remcom_out_buffer);
1311 }
1312
1313kgdb_exit:
1314 if (ks->pass_exception)
1315 error = 1;
1316 return error;
1317}
1318
1319static int kgdb_reenter_check(struct kgdb_state *ks)
1320{
1321 unsigned long addr;
1322
1323 if (atomic_read(&kgdb_active) != raw_smp_processor_id())
1324 return 0;
1325
1326 /* Panic on recursive debugger calls: */
1327 exception_level++;
1328 addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
1329 kgdb_deactivate_sw_breakpoints();
1330
1331 /*
1332 * If the break point removed ok at the place exception
1333 * occurred, try to recover and print a warning to the end
1334 * user because the user planted a breakpoint in a place that
1335 * KGDB needs in order to function.
1336 */
1337 if (kgdb_remove_sw_break(addr) == 0) {
1338 exception_level = 0;
1339 kgdb_skipexception(ks->ex_vector, ks->linux_regs);
1340 kgdb_activate_sw_breakpoints();
1341 printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed %lx\n",
1342 addr);
1343 WARN_ON_ONCE(1);
1344
1345 return 1;
1346 }
1347 remove_all_break();
1348 kgdb_skipexception(ks->ex_vector, ks->linux_regs);
1349
1350 if (exception_level > 1) {
1351 dump_stack();
1352 panic("Recursive entry to debugger");
1353 }
1354
1355 printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n");
1356 dump_stack();
1357 panic("Recursive entry to debugger");
1358
1359 return 1;
1360}
1361
1362static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs)
1363{
1364 unsigned long flags;
1365 int sstep_tries = 100;
1366 int error = 0;
1367 int i, cpu;
1368 int trace_on = 0;
1369acquirelock:
1370 /*
1371 * Interrupts will be restored by the 'trap return' code, except when
1372 * single stepping.
1373 */
1374 local_irq_save(flags);
1375
1376 cpu = ks->cpu;
1377 kgdb_info[cpu].debuggerinfo = regs;
1378 kgdb_info[cpu].task = current;
1379 /*
1380 * Make sure the above info reaches the primary CPU before
1381 * our cpu_in_kgdb[] flag setting does:
1382 */
1383 atomic_inc(&cpu_in_kgdb[cpu]);
1384
1385 /*
1386 * CPU will loop if it is a slave or request to become a kgdb
1387 * master cpu and acquire the kgdb_active lock:
1388 */
1389 while (1) {
1390 if (kgdb_info[cpu].exception_state & DCPU_WANT_MASTER) {
1391 if (atomic_cmpxchg(&kgdb_active, -1, cpu) == cpu)
1392 break;
1393 } else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) {
1394 if (!atomic_read(&passive_cpu_wait[cpu]))
1395 goto return_normal;
1396 } else {
1397return_normal:
1398 /* Return to normal operation by executing any
1399 * hw breakpoint fixup.
1400 */
1401 if (arch_kgdb_ops.correct_hw_break)
1402 arch_kgdb_ops.correct_hw_break();
1403 if (trace_on)
1404 tracing_on();
1405 atomic_dec(&cpu_in_kgdb[cpu]);
1406 touch_softlockup_watchdog_sync();
1407 clocksource_touch_watchdog();
1408 local_irq_restore(flags);
1409 return 0;
1410 }
1411 cpu_relax();
1412 }
1413
1414 /*
1415 * For single stepping, try to only enter on the processor
1416 * that was single stepping. To gaurd against a deadlock, the
1417 * kernel will only try for the value of sstep_tries before
1418 * giving up and continuing on.
1419 */
1420 if (atomic_read(&kgdb_cpu_doing_single_step) != -1 &&
1421 (kgdb_info[cpu].task &&
1422 kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) {
1423 atomic_set(&kgdb_active, -1);
1424 touch_softlockup_watchdog_sync();
1425 clocksource_touch_watchdog();
1426 local_irq_restore(flags);
1427
1428 goto acquirelock;
1429 }
1430
1431 if (!kgdb_io_ready(1)) {
1432 error = 1;
1433 goto kgdb_restore; /* No I/O connection, so resume the system */
1434 }
1435
1436 /*
1437 * Don't enter if we have hit a removed breakpoint.
1438 */
1439 if (kgdb_skipexception(ks->ex_vector, ks->linux_regs))
1440 goto kgdb_restore;
1441
1442 /* Call the I/O driver's pre_exception routine */
1443 if (kgdb_io_ops->pre_exception)
1444 kgdb_io_ops->pre_exception();
1445
1446 kgdb_disable_hw_debug(ks->linux_regs);
1447
1448 /*
1449 * Get the passive CPU lock which will hold all the non-primary
1450 * CPU in a spin state while the debugger is active
1451 */
1452 if (!kgdb_single_step) {
1453 for (i = 0; i < NR_CPUS; i++)
1454 atomic_inc(&passive_cpu_wait[i]);
1455 }
1456
1457#ifdef CONFIG_SMP
1458 /* Signal the other CPUs to enter kgdb_wait() */
1459 if ((!kgdb_single_step) && kgdb_do_roundup)
1460 kgdb_roundup_cpus(flags);
1461#endif
1462
1463 /*
1464 * Wait for the other CPUs to be notified and be waiting for us:
1465 */
1466 for_each_online_cpu(i) {
1467 while (!atomic_read(&cpu_in_kgdb[i]))
1468 cpu_relax();
1469 }
1470
1471 /*
1472 * At this point the primary processor is completely
1473 * in the debugger and all secondary CPUs are quiescent
1474 */
1475 kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code);
1476 kgdb_deactivate_sw_breakpoints();
1477 kgdb_single_step = 0;
1478 kgdb_contthread = current;
1479 exception_level = 0;
1480 trace_on = tracing_is_on();
1481 if (trace_on)
1482 tracing_off();
1483
1484 /* Talk to debugger with gdbserial protocol */
1485 error = gdb_serial_stub(ks);
1486
1487 /* Call the I/O driver's post_exception routine */
1488 if (kgdb_io_ops->post_exception)
1489 kgdb_io_ops->post_exception();
1490
1491 atomic_dec(&cpu_in_kgdb[ks->cpu]);
1492
1493 if (!kgdb_single_step) {
1494 for (i = NR_CPUS-1; i >= 0; i--)
1495 atomic_dec(&passive_cpu_wait[i]);
1496 /*
1497 * Wait till all the CPUs have quit
1498 * from the debugger.
1499 */
1500 for_each_online_cpu(i) {
1501 while (atomic_read(&cpu_in_kgdb[i]))
1502 cpu_relax();
1503 }
1504 }
1505
1506kgdb_restore:
1507 if (atomic_read(&kgdb_cpu_doing_single_step) != -1) {
1508 int sstep_cpu = atomic_read(&kgdb_cpu_doing_single_step);
1509 if (kgdb_info[sstep_cpu].task)
1510 kgdb_sstep_pid = kgdb_info[sstep_cpu].task->pid;
1511 else
1512 kgdb_sstep_pid = 0;
1513 }
1514 if (trace_on)
1515 tracing_on();
1516 /* Free kgdb_active */
1517 atomic_set(&kgdb_active, -1);
1518 touch_softlockup_watchdog_sync();
1519 clocksource_touch_watchdog();
1520 local_irq_restore(flags);
1521
1522 return error;
1523}
1524
1525/*
1526 * kgdb_handle_exception() - main entry point from a kernel exception
1527 *
1528 * Locking hierarchy:
1529 * interface locks, if any (begin_session)
1530 * kgdb lock (kgdb_active)
1531 */
1532int
1533kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
1534{
1535 struct kgdb_state kgdb_var;
1536 struct kgdb_state *ks = &kgdb_var;
1537 int ret;
1538
1539 ks->cpu = raw_smp_processor_id();
1540 ks->ex_vector = evector;
1541 ks->signo = signo;
1542 ks->ex_vector = evector;
1543 ks->err_code = ecode;
1544 ks->kgdb_usethreadid = 0;
1545 ks->linux_regs = regs;
1546
1547 if (kgdb_reenter_check(ks))
1548 return 0; /* Ouch, double exception ! */
1549 kgdb_info[ks->cpu].exception_state |= DCPU_WANT_MASTER;
1550 ret = kgdb_cpu_enter(ks, regs);
1551 kgdb_info[ks->cpu].exception_state &= ~DCPU_WANT_MASTER;
1552 return ret;
1553}
1554
1555int kgdb_nmicallback(int cpu, void *regs)
1556{
1557#ifdef CONFIG_SMP
1558 struct kgdb_state kgdb_var;
1559 struct kgdb_state *ks = &kgdb_var;
1560
1561 memset(ks, 0, sizeof(struct kgdb_state));
1562 ks->cpu = cpu;
1563 ks->linux_regs = regs;
1564
1565 if (!atomic_read(&cpu_in_kgdb[cpu]) &&
1566 atomic_read(&kgdb_active) != -1 &&
1567 atomic_read(&kgdb_active) != cpu) {
1568 kgdb_info[cpu].exception_state |= DCPU_IS_SLAVE;
1569 kgdb_cpu_enter(ks, regs);
1570 kgdb_info[cpu].exception_state &= ~DCPU_IS_SLAVE;
1571 return 0;
1572 }
1573#endif
1574 return 1;
1575}
1576
1577static void kgdb_console_write(struct console *co, const char *s,
1578 unsigned count)
1579{
1580 unsigned long flags;
1581
1582 /* If we're debugging, or KGDB has not connected, don't try
1583 * and print. */
1584 if (!kgdb_connected || atomic_read(&kgdb_active) != -1)
1585 return;
1586
1587 local_irq_save(flags);
1588 kgdb_msg_write(s, count);
1589 local_irq_restore(flags);
1590}
1591
1592static struct console kgdbcons = {
1593 .name = "kgdb",
1594 .write = kgdb_console_write,
1595 .flags = CON_PRINTBUFFER | CON_ENABLED,
1596 .index = -1,
1597};
1598
1599#ifdef CONFIG_MAGIC_SYSRQ
1600static void sysrq_handle_gdb(int key, struct tty_struct *tty)
1601{
1602 if (!kgdb_io_ops) {
1603 printk(KERN_CRIT "ERROR: No KGDB I/O module available\n");
1604 return;
1605 }
1606 if (!kgdb_connected)
1607 printk(KERN_CRIT "Entering KGDB\n");
1608
1609 kgdb_breakpoint();
1610}
1611
1612static struct sysrq_key_op sysrq_gdb_op = {
1613 .handler = sysrq_handle_gdb,
1614 .help_msg = "debug(G)",
1615 .action_msg = "DEBUG",
1616};
1617#endif
1618
1619static void kgdb_register_callbacks(void)
1620{
1621 if (!kgdb_io_module_registered) {
1622 kgdb_io_module_registered = 1;
1623 kgdb_arch_init();
1624#ifdef CONFIG_MAGIC_SYSRQ
1625 register_sysrq_key('g', &sysrq_gdb_op);
1626#endif
1627 if (kgdb_use_con && !kgdb_con_registered) {
1628 register_console(&kgdbcons);
1629 kgdb_con_registered = 1;
1630 }
1631 }
1632}
1633
1634static void kgdb_unregister_callbacks(void)
1635{
1636 /*
1637 * When this routine is called KGDB should unregister from the
1638 * panic handler and clean up, making sure it is not handling any
1639 * break exceptions at the time.
1640 */
1641 if (kgdb_io_module_registered) {
1642 kgdb_io_module_registered = 0;
1643 kgdb_arch_exit();
1644#ifdef CONFIG_MAGIC_SYSRQ
1645 unregister_sysrq_key('g', &sysrq_gdb_op);
1646#endif
1647 if (kgdb_con_registered) {
1648 unregister_console(&kgdbcons);
1649 kgdb_con_registered = 0;
1650 }
1651 }
1652}
1653
1654static void kgdb_initial_breakpoint(void)
1655{
1656 kgdb_break_asap = 0;
1657
1658 printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n");
1659 kgdb_breakpoint();
1660}
1661
1662/**
1663 * kgdb_register_io_module - register KGDB IO module
1664 * @new_kgdb_io_ops: the io ops vector
1665 *
1666 * Register it with the KGDB core.
1667 */
1668int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops)
1669{
1670 int err;
1671
1672 spin_lock(&kgdb_registration_lock);
1673
1674 if (kgdb_io_ops) {
1675 spin_unlock(&kgdb_registration_lock);
1676
1677 printk(KERN_ERR "kgdb: Another I/O driver is already "
1678 "registered with KGDB.\n");
1679 return -EBUSY;
1680 }
1681
1682 if (new_kgdb_io_ops->init) {
1683 err = new_kgdb_io_ops->init();
1684 if (err) {
1685 spin_unlock(&kgdb_registration_lock);
1686 return err;
1687 }
1688 }
1689
1690 kgdb_io_ops = new_kgdb_io_ops;
1691
1692 spin_unlock(&kgdb_registration_lock);
1693
1694 printk(KERN_INFO "kgdb: Registered I/O driver %s.\n",
1695 new_kgdb_io_ops->name);
1696
1697 /* Arm KGDB now. */
1698 kgdb_register_callbacks();
1699
1700 if (kgdb_break_asap)
1701 kgdb_initial_breakpoint();
1702
1703 return 0;
1704}
1705EXPORT_SYMBOL_GPL(kgdb_register_io_module);
1706
1707/**
1708 * kkgdb_unregister_io_module - unregister KGDB IO module
1709 * @old_kgdb_io_ops: the io ops vector
1710 *
1711 * Unregister it with the KGDB core.
1712 */
1713void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops)
1714{
1715 BUG_ON(kgdb_connected);
1716
1717 /*
1718 * KGDB is no longer able to communicate out, so
1719 * unregister our callbacks and reset state.
1720 */
1721 kgdb_unregister_callbacks();
1722
1723 spin_lock(&kgdb_registration_lock);
1724
1725 WARN_ON_ONCE(kgdb_io_ops != old_kgdb_io_ops);
1726 kgdb_io_ops = NULL;
1727
1728 spin_unlock(&kgdb_registration_lock);
1729
1730 printk(KERN_INFO
1731 "kgdb: Unregistered I/O driver %s, debugger disabled.\n",
1732 old_kgdb_io_ops->name);
1733}
1734EXPORT_SYMBOL_GPL(kgdb_unregister_io_module);
1735
1736/**
1737 * kgdb_breakpoint - generate breakpoint exception
1738 *
1739 * This function will generate a breakpoint exception. It is used at the
1740 * beginning of a program to sync up with a debugger and can be used
1741 * otherwise as a quick means to stop program execution and "break" into
1742 * the debugger.
1743 */
1744void kgdb_breakpoint(void)
1745{
1746 atomic_inc(&kgdb_setting_breakpoint);
1747 wmb(); /* Sync point before breakpoint */
1748 arch_kgdb_breakpoint();
1749 wmb(); /* Sync point after breakpoint */
1750 atomic_dec(&kgdb_setting_breakpoint);
1751}
1752EXPORT_SYMBOL_GPL(kgdb_breakpoint);
1753
1754static int __init opt_kgdb_wait(char *str)
1755{
1756 kgdb_break_asap = 1;
1757
1758 if (kgdb_io_module_registered)
1759 kgdb_initial_breakpoint();
1760
1761 return 0;
1762}
1763
1764early_param("kgdbwait", opt_kgdb_wait);
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-29 16:33:10 -0500