kgdb: gdb "monitor" -> kdb passthrough
[sfrench/cifs-2.6.git] / kernel / debug / gdbstub.c
1 /*
2  * Kernel Debug Core
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) 2005-2009 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
31 #include <linux/kernel.h>
32 #include <linux/kgdb.h>
33 #include <linux/kdb.h>
34 #include <linux/reboot.h>
35 #include <linux/uaccess.h>
36 #include <asm/cacheflush.h>
37 #include <asm/unaligned.h>
38 #include "debug_core.h"
39
40 #define KGDB_MAX_THREAD_QUERY 17
41
42 /* Our I/O buffers. */
43 static char                     remcom_in_buffer[BUFMAX];
44 static char                     remcom_out_buffer[BUFMAX];
45
46 /* Storage for the registers, in GDB format. */
47 static unsigned long            gdb_regs[(NUMREGBYTES +
48                                         sizeof(unsigned long) - 1) /
49                                         sizeof(unsigned long)];
50
51 /*
52  * GDB remote protocol parser:
53  */
54
55 static int hex(char ch)
56 {
57         if ((ch >= 'a') && (ch <= 'f'))
58                 return ch - 'a' + 10;
59         if ((ch >= '0') && (ch <= '9'))
60                 return ch - '0';
61         if ((ch >= 'A') && (ch <= 'F'))
62                 return ch - 'A' + 10;
63         return -1;
64 }
65
66 #ifdef CONFIG_KGDB_KDB
67 static int gdbstub_read_wait(void)
68 {
69         int ret = -1;
70         int i;
71
72         /* poll any additional I/O interfaces that are defined */
73         while (ret < 0)
74                 for (i = 0; kdb_poll_funcs[i] != NULL; i++) {
75                         ret = kdb_poll_funcs[i]();
76                         if (ret > 0)
77                                 break;
78                 }
79         return ret;
80 }
81 #else
82 static int gdbstub_read_wait(void)
83 {
84         int ret = dbg_io_ops->read_char();
85         while (ret == NO_POLL_CHAR)
86                 ret = dbg_io_ops->read_char();
87         return ret;
88 }
89 #endif
90 /* scan for the sequence $<data>#<checksum> */
91 static void get_packet(char *buffer)
92 {
93         unsigned char checksum;
94         unsigned char xmitcsum;
95         int count;
96         char ch;
97
98         do {
99                 /*
100                  * Spin and wait around for the start character, ignore all
101                  * other characters:
102                  */
103                 while ((ch = (gdbstub_read_wait())) != '$')
104                         /* nothing */;
105
106                 kgdb_connected = 1;
107                 checksum = 0;
108                 xmitcsum = -1;
109
110                 count = 0;
111
112                 /*
113                  * now, read until a # or end of buffer is found:
114                  */
115                 while (count < (BUFMAX - 1)) {
116                         ch = gdbstub_read_wait();
117                         if (ch == '#')
118                                 break;
119                         checksum = checksum + ch;
120                         buffer[count] = ch;
121                         count = count + 1;
122                 }
123                 buffer[count] = 0;
124
125                 if (ch == '#') {
126                         xmitcsum = hex(gdbstub_read_wait()) << 4;
127                         xmitcsum += hex(gdbstub_read_wait());
128
129                         if (checksum != xmitcsum)
130                                 /* failed checksum */
131                                 dbg_io_ops->write_char('-');
132                         else
133                                 /* successful transfer */
134                                 dbg_io_ops->write_char('+');
135                         if (dbg_io_ops->flush)
136                                 dbg_io_ops->flush();
137                 }
138         } while (checksum != xmitcsum);
139 }
140
141 /*
142  * Send the packet in buffer.
143  * Check for gdb connection if asked for.
144  */
145 static void put_packet(char *buffer)
146 {
147         unsigned char checksum;
148         int count;
149         char ch;
150
151         /*
152          * $<packet info>#<checksum>.
153          */
154         while (1) {
155                 dbg_io_ops->write_char('$');
156                 checksum = 0;
157                 count = 0;
158
159                 while ((ch = buffer[count])) {
160                         dbg_io_ops->write_char(ch);
161                         checksum += ch;
162                         count++;
163                 }
164
165                 dbg_io_ops->write_char('#');
166                 dbg_io_ops->write_char(hex_asc_hi(checksum));
167                 dbg_io_ops->write_char(hex_asc_lo(checksum));
168                 if (dbg_io_ops->flush)
169                         dbg_io_ops->flush();
170
171                 /* Now see what we get in reply. */
172                 ch = gdbstub_read_wait();
173
174                 if (ch == 3)
175                         ch = gdbstub_read_wait();
176
177                 /* If we get an ACK, we are done. */
178                 if (ch == '+')
179                         return;
180
181                 /*
182                  * If we get the start of another packet, this means
183                  * that GDB is attempting to reconnect.  We will NAK
184                  * the packet being sent, and stop trying to send this
185                  * packet.
186                  */
187                 if (ch == '$') {
188                         dbg_io_ops->write_char('-');
189                         if (dbg_io_ops->flush)
190                                 dbg_io_ops->flush();
191                         return;
192                 }
193         }
194 }
195
196 static char gdbmsgbuf[BUFMAX + 1];
197
198 void gdbstub_msg_write(const char *s, int len)
199 {
200         char *bufptr;
201         int wcount;
202         int i;
203
204         if (len == 0)
205                 len = strlen(s);
206
207         /* 'O'utput */
208         gdbmsgbuf[0] = 'O';
209
210         /* Fill and send buffers... */
211         while (len > 0) {
212                 bufptr = gdbmsgbuf + 1;
213
214                 /* Calculate how many this time */
215                 if ((len << 1) > (BUFMAX - 2))
216                         wcount = (BUFMAX - 2) >> 1;
217                 else
218                         wcount = len;
219
220                 /* Pack in hex chars */
221                 for (i = 0; i < wcount; i++)
222                         bufptr = pack_hex_byte(bufptr, s[i]);
223                 *bufptr = '\0';
224
225                 /* Move up */
226                 s += wcount;
227                 len -= wcount;
228
229                 /* Write packet */
230                 put_packet(gdbmsgbuf);
231         }
232 }
233
234 /*
235  * Convert the memory pointed to by mem into hex, placing result in
236  * buf.  Return a pointer to the last char put in buf (null). May
237  * return an error.
238  */
239 int kgdb_mem2hex(char *mem, char *buf, int count)
240 {
241         char *tmp;
242         int err;
243
244         /*
245          * We use the upper half of buf as an intermediate buffer for the
246          * raw memory copy.  Hex conversion will work against this one.
247          */
248         tmp = buf + count;
249
250         err = probe_kernel_read(tmp, mem, count);
251         if (!err) {
252                 while (count > 0) {
253                         buf = pack_hex_byte(buf, *tmp);
254                         tmp++;
255                         count--;
256                 }
257
258                 *buf = 0;
259         }
260
261         return err;
262 }
263
264 /*
265  * Convert the hex array pointed to by buf into binary to be placed in
266  * mem.  Return a pointer to the character AFTER the last byte
267  * written.  May return an error.
268  */
269 int kgdb_hex2mem(char *buf, char *mem, int count)
270 {
271         char *tmp_raw;
272         char *tmp_hex;
273
274         /*
275          * We use the upper half of buf as an intermediate buffer for the
276          * raw memory that is converted from hex.
277          */
278         tmp_raw = buf + count * 2;
279
280         tmp_hex = tmp_raw - 1;
281         while (tmp_hex >= buf) {
282                 tmp_raw--;
283                 *tmp_raw = hex(*tmp_hex--);
284                 *tmp_raw |= hex(*tmp_hex--) << 4;
285         }
286
287         return probe_kernel_write(mem, tmp_raw, count);
288 }
289
290 /*
291  * While we find nice hex chars, build a long_val.
292  * Return number of chars processed.
293  */
294 int kgdb_hex2long(char **ptr, unsigned long *long_val)
295 {
296         int hex_val;
297         int num = 0;
298         int negate = 0;
299
300         *long_val = 0;
301
302         if (**ptr == '-') {
303                 negate = 1;
304                 (*ptr)++;
305         }
306         while (**ptr) {
307                 hex_val = hex(**ptr);
308                 if (hex_val < 0)
309                         break;
310
311                 *long_val = (*long_val << 4) | hex_val;
312                 num++;
313                 (*ptr)++;
314         }
315
316         if (negate)
317                 *long_val = -*long_val;
318
319         return num;
320 }
321
322 /*
323  * Copy the binary array pointed to by buf into mem.  Fix $, #, and
324  * 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success.
325  * The input buf is overwitten with the result to write to mem.
326  */
327 static int kgdb_ebin2mem(char *buf, char *mem, int count)
328 {
329         int size = 0;
330         char *c = buf;
331
332         while (count-- > 0) {
333                 c[size] = *buf++;
334                 if (c[size] == 0x7d)
335                         c[size] = *buf++ ^ 0x20;
336                 size++;
337         }
338
339         return probe_kernel_write(mem, c, size);
340 }
341
342 /* Write memory due to an 'M' or 'X' packet. */
343 static int write_mem_msg(int binary)
344 {
345         char *ptr = &remcom_in_buffer[1];
346         unsigned long addr;
347         unsigned long length;
348         int err;
349
350         if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
351             kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
352                 if (binary)
353                         err = kgdb_ebin2mem(ptr, (char *)addr, length);
354                 else
355                         err = kgdb_hex2mem(ptr, (char *)addr, length);
356                 if (err)
357                         return err;
358                 if (CACHE_FLUSH_IS_SAFE)
359                         flush_icache_range(addr, addr + length);
360                 return 0;
361         }
362
363         return -EINVAL;
364 }
365
366 static void error_packet(char *pkt, int error)
367 {
368         error = -error;
369         pkt[0] = 'E';
370         pkt[1] = hex_asc[(error / 10)];
371         pkt[2] = hex_asc[(error % 10)];
372         pkt[3] = '\0';
373 }
374
375 /*
376  * Thread ID accessors. We represent a flat TID space to GDB, where
377  * the per CPU idle threads (which under Linux all have PID 0) are
378  * remapped to negative TIDs.
379  */
380
381 #define BUF_THREAD_ID_SIZE      16
382
383 static char *pack_threadid(char *pkt, unsigned char *id)
384 {
385         char *limit;
386
387         limit = pkt + BUF_THREAD_ID_SIZE;
388         while (pkt < limit)
389                 pkt = pack_hex_byte(pkt, *id++);
390
391         return pkt;
392 }
393
394 static void int_to_threadref(unsigned char *id, int value)
395 {
396         unsigned char *scan;
397         int i = 4;
398
399         scan = (unsigned char *)id;
400         while (i--)
401                 *scan++ = 0;
402         put_unaligned_be32(value, scan);
403 }
404
405 static struct task_struct *getthread(struct pt_regs *regs, int tid)
406 {
407         /*
408          * Non-positive TIDs are remapped to the cpu shadow information
409          */
410         if (tid == 0 || tid == -1)
411                 tid = -atomic_read(&kgdb_active) - 2;
412         if (tid < -1 && tid > -NR_CPUS - 2) {
413                 if (kgdb_info[-tid - 2].task)
414                         return kgdb_info[-tid - 2].task;
415                 else
416                         return idle_task(-tid - 2);
417         }
418         if (tid <= 0) {
419                 printk(KERN_ERR "KGDB: Internal thread select error\n");
420                 dump_stack();
421                 return NULL;
422         }
423
424         /*
425          * find_task_by_pid_ns() does not take the tasklist lock anymore
426          * but is nicely RCU locked - hence is a pretty resilient
427          * thing to use:
428          */
429         return find_task_by_pid_ns(tid, &init_pid_ns);
430 }
431
432
433 /*
434  * Remap normal tasks to their real PID,
435  * CPU shadow threads are mapped to -CPU - 2
436  */
437 static inline int shadow_pid(int realpid)
438 {
439         if (realpid)
440                 return realpid;
441
442         return -raw_smp_processor_id() - 2;
443 }
444
445 /*
446  * All the functions that start with gdb_cmd are the various
447  * operations to implement the handlers for the gdbserial protocol
448  * where KGDB is communicating with an external debugger
449  */
450
451 /* Handle the '?' status packets */
452 static void gdb_cmd_status(struct kgdb_state *ks)
453 {
454         /*
455          * We know that this packet is only sent
456          * during initial connect.  So to be safe,
457          * we clear out our breakpoints now in case
458          * GDB is reconnecting.
459          */
460         dbg_remove_all_break();
461
462         remcom_out_buffer[0] = 'S';
463         pack_hex_byte(&remcom_out_buffer[1], ks->signo);
464 }
465
466 /* Handle the 'g' get registers request */
467 static void gdb_cmd_getregs(struct kgdb_state *ks)
468 {
469         struct task_struct *thread;
470         void *local_debuggerinfo;
471         int i;
472
473         thread = kgdb_usethread;
474         if (!thread) {
475                 thread = kgdb_info[ks->cpu].task;
476                 local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
477         } else {
478                 local_debuggerinfo = NULL;
479                 for_each_online_cpu(i) {
480                         /*
481                          * Try to find the task on some other
482                          * or possibly this node if we do not
483                          * find the matching task then we try
484                          * to approximate the results.
485                          */
486                         if (thread == kgdb_info[i].task)
487                                 local_debuggerinfo = kgdb_info[i].debuggerinfo;
488                 }
489         }
490
491         /*
492          * All threads that don't have debuggerinfo should be
493          * in schedule() sleeping, since all other CPUs
494          * are in kgdb_wait, and thus have debuggerinfo.
495          */
496         if (local_debuggerinfo) {
497                 pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
498         } else {
499                 /*
500                  * Pull stuff saved during switch_to; nothing
501                  * else is accessible (or even particularly
502                  * relevant).
503                  *
504                  * This should be enough for a stack trace.
505                  */
506                 sleeping_thread_to_gdb_regs(gdb_regs, thread);
507         }
508         kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
509 }
510
511 /* Handle the 'G' set registers request */
512 static void gdb_cmd_setregs(struct kgdb_state *ks)
513 {
514         kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
515
516         if (kgdb_usethread && kgdb_usethread != current) {
517                 error_packet(remcom_out_buffer, -EINVAL);
518         } else {
519                 gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
520                 strcpy(remcom_out_buffer, "OK");
521         }
522 }
523
524 /* Handle the 'm' memory read bytes */
525 static void gdb_cmd_memread(struct kgdb_state *ks)
526 {
527         char *ptr = &remcom_in_buffer[1];
528         unsigned long length;
529         unsigned long addr;
530         int err;
531
532         if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
533                                         kgdb_hex2long(&ptr, &length) > 0) {
534                 err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
535                 if (err)
536                         error_packet(remcom_out_buffer, err);
537         } else {
538                 error_packet(remcom_out_buffer, -EINVAL);
539         }
540 }
541
542 /* Handle the 'M' memory write bytes */
543 static void gdb_cmd_memwrite(struct kgdb_state *ks)
544 {
545         int err = write_mem_msg(0);
546
547         if (err)
548                 error_packet(remcom_out_buffer, err);
549         else
550                 strcpy(remcom_out_buffer, "OK");
551 }
552
553 /* Handle the 'X' memory binary write bytes */
554 static void gdb_cmd_binwrite(struct kgdb_state *ks)
555 {
556         int err = write_mem_msg(1);
557
558         if (err)
559                 error_packet(remcom_out_buffer, err);
560         else
561                 strcpy(remcom_out_buffer, "OK");
562 }
563
564 /* Handle the 'D' or 'k', detach or kill packets */
565 static void gdb_cmd_detachkill(struct kgdb_state *ks)
566 {
567         int error;
568
569         /* The detach case */
570         if (remcom_in_buffer[0] == 'D') {
571                 error = dbg_remove_all_break();
572                 if (error < 0) {
573                         error_packet(remcom_out_buffer, error);
574                 } else {
575                         strcpy(remcom_out_buffer, "OK");
576                         kgdb_connected = 0;
577                 }
578                 put_packet(remcom_out_buffer);
579         } else {
580                 /*
581                  * Assume the kill case, with no exit code checking,
582                  * trying to force detach the debugger:
583                  */
584                 dbg_remove_all_break();
585                 kgdb_connected = 0;
586         }
587 }
588
589 /* Handle the 'R' reboot packets */
590 static int gdb_cmd_reboot(struct kgdb_state *ks)
591 {
592         /* For now, only honor R0 */
593         if (strcmp(remcom_in_buffer, "R0") == 0) {
594                 printk(KERN_CRIT "Executing emergency reboot\n");
595                 strcpy(remcom_out_buffer, "OK");
596                 put_packet(remcom_out_buffer);
597
598                 /*
599                  * Execution should not return from
600                  * machine_emergency_restart()
601                  */
602                 machine_emergency_restart();
603                 kgdb_connected = 0;
604
605                 return 1;
606         }
607         return 0;
608 }
609
610 /* Handle the 'q' query packets */
611 static void gdb_cmd_query(struct kgdb_state *ks)
612 {
613         struct task_struct *g;
614         struct task_struct *p;
615         unsigned char thref[8];
616         char *ptr;
617         int i;
618         int cpu;
619         int finished = 0;
620
621         switch (remcom_in_buffer[1]) {
622         case 's':
623         case 'f':
624                 if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) {
625                         error_packet(remcom_out_buffer, -EINVAL);
626                         break;
627                 }
628
629                 i = 0;
630                 remcom_out_buffer[0] = 'm';
631                 ptr = remcom_out_buffer + 1;
632                 if (remcom_in_buffer[1] == 'f') {
633                         /* Each cpu is a shadow thread */
634                         for_each_online_cpu(cpu) {
635                                 ks->thr_query = 0;
636                                 int_to_threadref(thref, -cpu - 2);
637                                 pack_threadid(ptr, thref);
638                                 ptr += BUF_THREAD_ID_SIZE;
639                                 *(ptr++) = ',';
640                                 i++;
641                         }
642                 }
643
644                 do_each_thread(g, p) {
645                         if (i >= ks->thr_query && !finished) {
646                                 int_to_threadref(thref, p->pid);
647                                 pack_threadid(ptr, thref);
648                                 ptr += BUF_THREAD_ID_SIZE;
649                                 *(ptr++) = ',';
650                                 ks->thr_query++;
651                                 if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0)
652                                         finished = 1;
653                         }
654                         i++;
655                 } while_each_thread(g, p);
656
657                 *(--ptr) = '\0';
658                 break;
659
660         case 'C':
661                 /* Current thread id */
662                 strcpy(remcom_out_buffer, "QC");
663                 ks->threadid = shadow_pid(current->pid);
664                 int_to_threadref(thref, ks->threadid);
665                 pack_threadid(remcom_out_buffer + 2, thref);
666                 break;
667         case 'T':
668                 if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) {
669                         error_packet(remcom_out_buffer, -EINVAL);
670                         break;
671                 }
672                 ks->threadid = 0;
673                 ptr = remcom_in_buffer + 17;
674                 kgdb_hex2long(&ptr, &ks->threadid);
675                 if (!getthread(ks->linux_regs, ks->threadid)) {
676                         error_packet(remcom_out_buffer, -EINVAL);
677                         break;
678                 }
679                 if ((int)ks->threadid > 0) {
680                         kgdb_mem2hex(getthread(ks->linux_regs,
681                                         ks->threadid)->comm,
682                                         remcom_out_buffer, 16);
683                 } else {
684                         static char tmpstr[23 + BUF_THREAD_ID_SIZE];
685
686                         sprintf(tmpstr, "shadowCPU%d",
687                                         (int)(-ks->threadid - 2));
688                         kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
689                 }
690                 break;
691 #ifdef CONFIG_KGDB_KDB
692         case 'R':
693                 if (strncmp(remcom_in_buffer, "qRcmd,", 6) == 0) {
694                         int len = strlen(remcom_in_buffer + 6);
695
696                         if ((len % 2) != 0) {
697                                 strcpy(remcom_out_buffer, "E01");
698                                 break;
699                         }
700                         kgdb_hex2mem(remcom_in_buffer + 6,
701                                      remcom_out_buffer, len);
702                         len = len / 2;
703                         remcom_out_buffer[len++] = 0;
704
705                         kdb_parse(remcom_out_buffer);
706                         strcpy(remcom_out_buffer, "OK");
707                 }
708                 break;
709 #endif
710         }
711 }
712
713 /* Handle the 'H' task query packets */
714 static void gdb_cmd_task(struct kgdb_state *ks)
715 {
716         struct task_struct *thread;
717         char *ptr;
718
719         switch (remcom_in_buffer[1]) {
720         case 'g':
721                 ptr = &remcom_in_buffer[2];
722                 kgdb_hex2long(&ptr, &ks->threadid);
723                 thread = getthread(ks->linux_regs, ks->threadid);
724                 if (!thread && ks->threadid > 0) {
725                         error_packet(remcom_out_buffer, -EINVAL);
726                         break;
727                 }
728                 kgdb_usethread = thread;
729                 ks->kgdb_usethreadid = ks->threadid;
730                 strcpy(remcom_out_buffer, "OK");
731                 break;
732         case 'c':
733                 ptr = &remcom_in_buffer[2];
734                 kgdb_hex2long(&ptr, &ks->threadid);
735                 if (!ks->threadid) {
736                         kgdb_contthread = NULL;
737                 } else {
738                         thread = getthread(ks->linux_regs, ks->threadid);
739                         if (!thread && ks->threadid > 0) {
740                                 error_packet(remcom_out_buffer, -EINVAL);
741                                 break;
742                         }
743                         kgdb_contthread = thread;
744                 }
745                 strcpy(remcom_out_buffer, "OK");
746                 break;
747         }
748 }
749
750 /* Handle the 'T' thread query packets */
751 static void gdb_cmd_thread(struct kgdb_state *ks)
752 {
753         char *ptr = &remcom_in_buffer[1];
754         struct task_struct *thread;
755
756         kgdb_hex2long(&ptr, &ks->threadid);
757         thread = getthread(ks->linux_regs, ks->threadid);
758         if (thread)
759                 strcpy(remcom_out_buffer, "OK");
760         else
761                 error_packet(remcom_out_buffer, -EINVAL);
762 }
763
764 /* Handle the 'z' or 'Z' breakpoint remove or set packets */
765 static void gdb_cmd_break(struct kgdb_state *ks)
766 {
767         /*
768          * Since GDB-5.3, it's been drafted that '0' is a software
769          * breakpoint, '1' is a hardware breakpoint, so let's do that.
770          */
771         char *bpt_type = &remcom_in_buffer[1];
772         char *ptr = &remcom_in_buffer[2];
773         unsigned long addr;
774         unsigned long length;
775         int error = 0;
776
777         if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
778                 /* Unsupported */
779                 if (*bpt_type > '4')
780                         return;
781         } else {
782                 if (*bpt_type != '0' && *bpt_type != '1')
783                         /* Unsupported. */
784                         return;
785         }
786
787         /*
788          * Test if this is a hardware breakpoint, and
789          * if we support it:
790          */
791         if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
792                 /* Unsupported. */
793                 return;
794
795         if (*(ptr++) != ',') {
796                 error_packet(remcom_out_buffer, -EINVAL);
797                 return;
798         }
799         if (!kgdb_hex2long(&ptr, &addr)) {
800                 error_packet(remcom_out_buffer, -EINVAL);
801                 return;
802         }
803         if (*(ptr++) != ',' ||
804                 !kgdb_hex2long(&ptr, &length)) {
805                 error_packet(remcom_out_buffer, -EINVAL);
806                 return;
807         }
808
809         if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
810                 error = dbg_set_sw_break(addr);
811         else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
812                 error = dbg_remove_sw_break(addr);
813         else if (remcom_in_buffer[0] == 'Z')
814                 error = arch_kgdb_ops.set_hw_breakpoint(addr,
815                         (int)length, *bpt_type - '0');
816         else if (remcom_in_buffer[0] == 'z')
817                 error = arch_kgdb_ops.remove_hw_breakpoint(addr,
818                         (int) length, *bpt_type - '0');
819
820         if (error == 0)
821                 strcpy(remcom_out_buffer, "OK");
822         else
823                 error_packet(remcom_out_buffer, error);
824 }
825
826 /* Handle the 'C' signal / exception passing packets */
827 static int gdb_cmd_exception_pass(struct kgdb_state *ks)
828 {
829         /* C09 == pass exception
830          * C15 == detach kgdb, pass exception
831          */
832         if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
833
834                 ks->pass_exception = 1;
835                 remcom_in_buffer[0] = 'c';
836
837         } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
838
839                 ks->pass_exception = 1;
840                 remcom_in_buffer[0] = 'D';
841                 dbg_remove_all_break();
842                 kgdb_connected = 0;
843                 return 1;
844
845         } else {
846                 gdbstub_msg_write("KGDB only knows signal 9 (pass)"
847                         " and 15 (pass and disconnect)\n"
848                         "Executing a continue without signal passing\n", 0);
849                 remcom_in_buffer[0] = 'c';
850         }
851
852         /* Indicate fall through */
853         return -1;
854 }
855
856 /*
857  * This function performs all gdbserial command procesing
858  */
859 int gdb_serial_stub(struct kgdb_state *ks)
860 {
861         int error = 0;
862         int tmp;
863
864         /* Clear the out buffer. */
865         memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
866
867         if (kgdb_connected) {
868                 unsigned char thref[8];
869                 char *ptr;
870
871                 /* Reply to host that an exception has occurred */
872                 ptr = remcom_out_buffer;
873                 *ptr++ = 'T';
874                 ptr = pack_hex_byte(ptr, ks->signo);
875                 ptr += strlen(strcpy(ptr, "thread:"));
876                 int_to_threadref(thref, shadow_pid(current->pid));
877                 ptr = pack_threadid(ptr, thref);
878                 *ptr++ = ';';
879                 put_packet(remcom_out_buffer);
880         }
881
882         kgdb_usethread = kgdb_info[ks->cpu].task;
883         ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
884         ks->pass_exception = 0;
885
886         while (1) {
887                 error = 0;
888
889                 /* Clear the out buffer. */
890                 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
891
892                 get_packet(remcom_in_buffer);
893
894                 switch (remcom_in_buffer[0]) {
895                 case '?': /* gdbserial status */
896                         gdb_cmd_status(ks);
897                         break;
898                 case 'g': /* return the value of the CPU registers */
899                         gdb_cmd_getregs(ks);
900                         break;
901                 case 'G': /* set the value of the CPU registers - return OK */
902                         gdb_cmd_setregs(ks);
903                         break;
904                 case 'm': /* mAA..AA,LLLL  Read LLLL bytes at address AA..AA */
905                         gdb_cmd_memread(ks);
906                         break;
907                 case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
908                         gdb_cmd_memwrite(ks);
909                         break;
910                 case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
911                         gdb_cmd_binwrite(ks);
912                         break;
913                         /* kill or detach. KGDB should treat this like a
914                          * continue.
915                          */
916                 case 'D': /* Debugger detach */
917                 case 'k': /* Debugger detach via kill */
918                         gdb_cmd_detachkill(ks);
919                         goto default_handle;
920                 case 'R': /* Reboot */
921                         if (gdb_cmd_reboot(ks))
922                                 goto default_handle;
923                         break;
924                 case 'q': /* query command */
925                         gdb_cmd_query(ks);
926                         break;
927                 case 'H': /* task related */
928                         gdb_cmd_task(ks);
929                         break;
930                 case 'T': /* Query thread status */
931                         gdb_cmd_thread(ks);
932                         break;
933                 case 'z': /* Break point remove */
934                 case 'Z': /* Break point set */
935                         gdb_cmd_break(ks);
936                         break;
937 #ifdef CONFIG_KGDB_KDB
938                 case '3': /* Escape into back into kdb */
939                         if (remcom_in_buffer[1] == '\0') {
940                                 gdb_cmd_detachkill(ks);
941                                 return DBG_PASS_EVENT;
942                         }
943 #endif
944                 case 'C': /* Exception passing */
945                         tmp = gdb_cmd_exception_pass(ks);
946                         if (tmp > 0)
947                                 goto default_handle;
948                         if (tmp == 0)
949                                 break;
950                         /* Fall through on tmp < 0 */
951                 case 'c': /* Continue packet */
952                 case 's': /* Single step packet */
953                         if (kgdb_contthread && kgdb_contthread != current) {
954                                 /* Can't switch threads in kgdb */
955                                 error_packet(remcom_out_buffer, -EINVAL);
956                                 break;
957                         }
958                         dbg_activate_sw_breakpoints();
959                         /* Fall through to default processing */
960                 default:
961 default_handle:
962                         error = kgdb_arch_handle_exception(ks->ex_vector,
963                                                 ks->signo,
964                                                 ks->err_code,
965                                                 remcom_in_buffer,
966                                                 remcom_out_buffer,
967                                                 ks->linux_regs);
968                         /*
969                          * Leave cmd processing on error, detach,
970                          * kill, continue, or single step.
971                          */
972                         if (error >= 0 || remcom_in_buffer[0] == 'D' ||
973                             remcom_in_buffer[0] == 'k') {
974                                 error = 0;
975                                 goto kgdb_exit;
976                         }
977
978                 }
979
980                 /* reply to the request */
981                 put_packet(remcom_out_buffer);
982         }
983
984 kgdb_exit:
985         if (ks->pass_exception)
986                 error = 1;
987         return error;
988 }
989
990 int gdbstub_state(struct kgdb_state *ks, char *cmd)
991 {
992         int error;
993
994         switch (cmd[0]) {
995         case 'e':
996                 error = kgdb_arch_handle_exception(ks->ex_vector,
997                                                    ks->signo,
998                                                    ks->err_code,
999                                                    remcom_in_buffer,
1000                                                    remcom_out_buffer,
1001                                                    ks->linux_regs);
1002                 return error;
1003         case 's':
1004         case 'c':
1005                 strcpy(remcom_in_buffer, cmd);
1006                 return 0;
1007         case '?':
1008                 gdb_cmd_status(ks);
1009                 break;
1010         case '\0':
1011                 strcpy(remcom_out_buffer, "");
1012                 break;
1013         }
1014         dbg_io_ops->write_char('+');
1015         put_packet(remcom_out_buffer);
1016         return 0;
1017 }