3c000490a7dd1938cb20a3f410ab31223bbf8c18
[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         /* 'O'utput */
205         gdbmsgbuf[0] = 'O';
206
207         /* Fill and send buffers... */
208         while (len > 0) {
209                 bufptr = gdbmsgbuf + 1;
210
211                 /* Calculate how many this time */
212                 if ((len << 1) > (BUFMAX - 2))
213                         wcount = (BUFMAX - 2) >> 1;
214                 else
215                         wcount = len;
216
217                 /* Pack in hex chars */
218                 for (i = 0; i < wcount; i++)
219                         bufptr = pack_hex_byte(bufptr, s[i]);
220                 *bufptr = '\0';
221
222                 /* Move up */
223                 s += wcount;
224                 len -= wcount;
225
226                 /* Write packet */
227                 put_packet(gdbmsgbuf);
228         }
229 }
230
231 /*
232  * Convert the memory pointed to by mem into hex, placing result in
233  * buf.  Return a pointer to the last char put in buf (null). May
234  * return an error.
235  */
236 int kgdb_mem2hex(char *mem, char *buf, int count)
237 {
238         char *tmp;
239         int err;
240
241         /*
242          * We use the upper half of buf as an intermediate buffer for the
243          * raw memory copy.  Hex conversion will work against this one.
244          */
245         tmp = buf + count;
246
247         err = probe_kernel_read(tmp, mem, count);
248         if (!err) {
249                 while (count > 0) {
250                         buf = pack_hex_byte(buf, *tmp);
251                         tmp++;
252                         count--;
253                 }
254
255                 *buf = 0;
256         }
257
258         return err;
259 }
260
261 /*
262  * Convert the hex array pointed to by buf into binary to be placed in
263  * mem.  Return a pointer to the character AFTER the last byte
264  * written.  May return an error.
265  */
266 int kgdb_hex2mem(char *buf, char *mem, int count)
267 {
268         char *tmp_raw;
269         char *tmp_hex;
270
271         /*
272          * We use the upper half of buf as an intermediate buffer for the
273          * raw memory that is converted from hex.
274          */
275         tmp_raw = buf + count * 2;
276
277         tmp_hex = tmp_raw - 1;
278         while (tmp_hex >= buf) {
279                 tmp_raw--;
280                 *tmp_raw = hex(*tmp_hex--);
281                 *tmp_raw |= hex(*tmp_hex--) << 4;
282         }
283
284         return probe_kernel_write(mem, tmp_raw, count);
285 }
286
287 /*
288  * While we find nice hex chars, build a long_val.
289  * Return number of chars processed.
290  */
291 int kgdb_hex2long(char **ptr, unsigned long *long_val)
292 {
293         int hex_val;
294         int num = 0;
295         int negate = 0;
296
297         *long_val = 0;
298
299         if (**ptr == '-') {
300                 negate = 1;
301                 (*ptr)++;
302         }
303         while (**ptr) {
304                 hex_val = hex(**ptr);
305                 if (hex_val < 0)
306                         break;
307
308                 *long_val = (*long_val << 4) | hex_val;
309                 num++;
310                 (*ptr)++;
311         }
312
313         if (negate)
314                 *long_val = -*long_val;
315
316         return num;
317 }
318
319 /*
320  * Copy the binary array pointed to by buf into mem.  Fix $, #, and
321  * 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success.
322  * The input buf is overwitten with the result to write to mem.
323  */
324 static int kgdb_ebin2mem(char *buf, char *mem, int count)
325 {
326         int size = 0;
327         char *c = buf;
328
329         while (count-- > 0) {
330                 c[size] = *buf++;
331                 if (c[size] == 0x7d)
332                         c[size] = *buf++ ^ 0x20;
333                 size++;
334         }
335
336         return probe_kernel_write(mem, c, size);
337 }
338
339 /* Write memory due to an 'M' or 'X' packet. */
340 static int write_mem_msg(int binary)
341 {
342         char *ptr = &remcom_in_buffer[1];
343         unsigned long addr;
344         unsigned long length;
345         int err;
346
347         if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
348             kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
349                 if (binary)
350                         err = kgdb_ebin2mem(ptr, (char *)addr, length);
351                 else
352                         err = kgdb_hex2mem(ptr, (char *)addr, length);
353                 if (err)
354                         return err;
355                 if (CACHE_FLUSH_IS_SAFE)
356                         flush_icache_range(addr, addr + length);
357                 return 0;
358         }
359
360         return -EINVAL;
361 }
362
363 static void error_packet(char *pkt, int error)
364 {
365         error = -error;
366         pkt[0] = 'E';
367         pkt[1] = hex_asc[(error / 10)];
368         pkt[2] = hex_asc[(error % 10)];
369         pkt[3] = '\0';
370 }
371
372 /*
373  * Thread ID accessors. We represent a flat TID space to GDB, where
374  * the per CPU idle threads (which under Linux all have PID 0) are
375  * remapped to negative TIDs.
376  */
377
378 #define BUF_THREAD_ID_SIZE      16
379
380 static char *pack_threadid(char *pkt, unsigned char *id)
381 {
382         char *limit;
383
384         limit = pkt + BUF_THREAD_ID_SIZE;
385         while (pkt < limit)
386                 pkt = pack_hex_byte(pkt, *id++);
387
388         return pkt;
389 }
390
391 static void int_to_threadref(unsigned char *id, int value)
392 {
393         unsigned char *scan;
394         int i = 4;
395
396         scan = (unsigned char *)id;
397         while (i--)
398                 *scan++ = 0;
399         put_unaligned_be32(value, scan);
400 }
401
402 static struct task_struct *getthread(struct pt_regs *regs, int tid)
403 {
404         /*
405          * Non-positive TIDs are remapped to the cpu shadow information
406          */
407         if (tid == 0 || tid == -1)
408                 tid = -atomic_read(&kgdb_active) - 2;
409         if (tid < -1 && tid > -NR_CPUS - 2) {
410                 if (kgdb_info[-tid - 2].task)
411                         return kgdb_info[-tid - 2].task;
412                 else
413                         return idle_task(-tid - 2);
414         }
415         if (tid <= 0) {
416                 printk(KERN_ERR "KGDB: Internal thread select error\n");
417                 dump_stack();
418                 return NULL;
419         }
420
421         /*
422          * find_task_by_pid_ns() does not take the tasklist lock anymore
423          * but is nicely RCU locked - hence is a pretty resilient
424          * thing to use:
425          */
426         return find_task_by_pid_ns(tid, &init_pid_ns);
427 }
428
429
430 /*
431  * Remap normal tasks to their real PID,
432  * CPU shadow threads are mapped to -CPU - 2
433  */
434 static inline int shadow_pid(int realpid)
435 {
436         if (realpid)
437                 return realpid;
438
439         return -raw_smp_processor_id() - 2;
440 }
441
442 /*
443  * All the functions that start with gdb_cmd are the various
444  * operations to implement the handlers for the gdbserial protocol
445  * where KGDB is communicating with an external debugger
446  */
447
448 /* Handle the '?' status packets */
449 static void gdb_cmd_status(struct kgdb_state *ks)
450 {
451         /*
452          * We know that this packet is only sent
453          * during initial connect.  So to be safe,
454          * we clear out our breakpoints now in case
455          * GDB is reconnecting.
456          */
457         dbg_remove_all_break();
458
459         remcom_out_buffer[0] = 'S';
460         pack_hex_byte(&remcom_out_buffer[1], ks->signo);
461 }
462
463 /* Handle the 'g' get registers request */
464 static void gdb_cmd_getregs(struct kgdb_state *ks)
465 {
466         struct task_struct *thread;
467         void *local_debuggerinfo;
468         int i;
469
470         thread = kgdb_usethread;
471         if (!thread) {
472                 thread = kgdb_info[ks->cpu].task;
473                 local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
474         } else {
475                 local_debuggerinfo = NULL;
476                 for_each_online_cpu(i) {
477                         /*
478                          * Try to find the task on some other
479                          * or possibly this node if we do not
480                          * find the matching task then we try
481                          * to approximate the results.
482                          */
483                         if (thread == kgdb_info[i].task)
484                                 local_debuggerinfo = kgdb_info[i].debuggerinfo;
485                 }
486         }
487
488         /*
489          * All threads that don't have debuggerinfo should be
490          * in schedule() sleeping, since all other CPUs
491          * are in kgdb_wait, and thus have debuggerinfo.
492          */
493         if (local_debuggerinfo) {
494                 pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
495         } else {
496                 /*
497                  * Pull stuff saved during switch_to; nothing
498                  * else is accessible (or even particularly
499                  * relevant).
500                  *
501                  * This should be enough for a stack trace.
502                  */
503                 sleeping_thread_to_gdb_regs(gdb_regs, thread);
504         }
505         kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
506 }
507
508 /* Handle the 'G' set registers request */
509 static void gdb_cmd_setregs(struct kgdb_state *ks)
510 {
511         kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
512
513         if (kgdb_usethread && kgdb_usethread != current) {
514                 error_packet(remcom_out_buffer, -EINVAL);
515         } else {
516                 gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
517                 strcpy(remcom_out_buffer, "OK");
518         }
519 }
520
521 /* Handle the 'm' memory read bytes */
522 static void gdb_cmd_memread(struct kgdb_state *ks)
523 {
524         char *ptr = &remcom_in_buffer[1];
525         unsigned long length;
526         unsigned long addr;
527         int err;
528
529         if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
530                                         kgdb_hex2long(&ptr, &length) > 0) {
531                 err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
532                 if (err)
533                         error_packet(remcom_out_buffer, err);
534         } else {
535                 error_packet(remcom_out_buffer, -EINVAL);
536         }
537 }
538
539 /* Handle the 'M' memory write bytes */
540 static void gdb_cmd_memwrite(struct kgdb_state *ks)
541 {
542         int err = write_mem_msg(0);
543
544         if (err)
545                 error_packet(remcom_out_buffer, err);
546         else
547                 strcpy(remcom_out_buffer, "OK");
548 }
549
550 /* Handle the 'X' memory binary write bytes */
551 static void gdb_cmd_binwrite(struct kgdb_state *ks)
552 {
553         int err = write_mem_msg(1);
554
555         if (err)
556                 error_packet(remcom_out_buffer, err);
557         else
558                 strcpy(remcom_out_buffer, "OK");
559 }
560
561 /* Handle the 'D' or 'k', detach or kill packets */
562 static void gdb_cmd_detachkill(struct kgdb_state *ks)
563 {
564         int error;
565
566         /* The detach case */
567         if (remcom_in_buffer[0] == 'D') {
568                 error = dbg_remove_all_break();
569                 if (error < 0) {
570                         error_packet(remcom_out_buffer, error);
571                 } else {
572                         strcpy(remcom_out_buffer, "OK");
573                         kgdb_connected = 0;
574                 }
575                 put_packet(remcom_out_buffer);
576         } else {
577                 /*
578                  * Assume the kill case, with no exit code checking,
579                  * trying to force detach the debugger:
580                  */
581                 dbg_remove_all_break();
582                 kgdb_connected = 0;
583         }
584 }
585
586 /* Handle the 'R' reboot packets */
587 static int gdb_cmd_reboot(struct kgdb_state *ks)
588 {
589         /* For now, only honor R0 */
590         if (strcmp(remcom_in_buffer, "R0") == 0) {
591                 printk(KERN_CRIT "Executing emergency reboot\n");
592                 strcpy(remcom_out_buffer, "OK");
593                 put_packet(remcom_out_buffer);
594
595                 /*
596                  * Execution should not return from
597                  * machine_emergency_restart()
598                  */
599                 machine_emergency_restart();
600                 kgdb_connected = 0;
601
602                 return 1;
603         }
604         return 0;
605 }
606
607 /* Handle the 'q' query packets */
608 static void gdb_cmd_query(struct kgdb_state *ks)
609 {
610         struct task_struct *g;
611         struct task_struct *p;
612         unsigned char thref[8];
613         char *ptr;
614         int i;
615         int cpu;
616         int finished = 0;
617
618         switch (remcom_in_buffer[1]) {
619         case 's':
620         case 'f':
621                 if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) {
622                         error_packet(remcom_out_buffer, -EINVAL);
623                         break;
624                 }
625
626                 i = 0;
627                 remcom_out_buffer[0] = 'm';
628                 ptr = remcom_out_buffer + 1;
629                 if (remcom_in_buffer[1] == 'f') {
630                         /* Each cpu is a shadow thread */
631                         for_each_online_cpu(cpu) {
632                                 ks->thr_query = 0;
633                                 int_to_threadref(thref, -cpu - 2);
634                                 pack_threadid(ptr, thref);
635                                 ptr += BUF_THREAD_ID_SIZE;
636                                 *(ptr++) = ',';
637                                 i++;
638                         }
639                 }
640
641                 do_each_thread(g, p) {
642                         if (i >= ks->thr_query && !finished) {
643                                 int_to_threadref(thref, p->pid);
644                                 pack_threadid(ptr, thref);
645                                 ptr += BUF_THREAD_ID_SIZE;
646                                 *(ptr++) = ',';
647                                 ks->thr_query++;
648                                 if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0)
649                                         finished = 1;
650                         }
651                         i++;
652                 } while_each_thread(g, p);
653
654                 *(--ptr) = '\0';
655                 break;
656
657         case 'C':
658                 /* Current thread id */
659                 strcpy(remcom_out_buffer, "QC");
660                 ks->threadid = shadow_pid(current->pid);
661                 int_to_threadref(thref, ks->threadid);
662                 pack_threadid(remcom_out_buffer + 2, thref);
663                 break;
664         case 'T':
665                 if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) {
666                         error_packet(remcom_out_buffer, -EINVAL);
667                         break;
668                 }
669                 ks->threadid = 0;
670                 ptr = remcom_in_buffer + 17;
671                 kgdb_hex2long(&ptr, &ks->threadid);
672                 if (!getthread(ks->linux_regs, ks->threadid)) {
673                         error_packet(remcom_out_buffer, -EINVAL);
674                         break;
675                 }
676                 if ((int)ks->threadid > 0) {
677                         kgdb_mem2hex(getthread(ks->linux_regs,
678                                         ks->threadid)->comm,
679                                         remcom_out_buffer, 16);
680                 } else {
681                         static char tmpstr[23 + BUF_THREAD_ID_SIZE];
682
683                         sprintf(tmpstr, "shadowCPU%d",
684                                         (int)(-ks->threadid - 2));
685                         kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
686                 }
687                 break;
688         }
689 }
690
691 /* Handle the 'H' task query packets */
692 static void gdb_cmd_task(struct kgdb_state *ks)
693 {
694         struct task_struct *thread;
695         char *ptr;
696
697         switch (remcom_in_buffer[1]) {
698         case 'g':
699                 ptr = &remcom_in_buffer[2];
700                 kgdb_hex2long(&ptr, &ks->threadid);
701                 thread = getthread(ks->linux_regs, ks->threadid);
702                 if (!thread && ks->threadid > 0) {
703                         error_packet(remcom_out_buffer, -EINVAL);
704                         break;
705                 }
706                 kgdb_usethread = thread;
707                 ks->kgdb_usethreadid = ks->threadid;
708                 strcpy(remcom_out_buffer, "OK");
709                 break;
710         case 'c':
711                 ptr = &remcom_in_buffer[2];
712                 kgdb_hex2long(&ptr, &ks->threadid);
713                 if (!ks->threadid) {
714                         kgdb_contthread = NULL;
715                 } else {
716                         thread = getthread(ks->linux_regs, ks->threadid);
717                         if (!thread && ks->threadid > 0) {
718                                 error_packet(remcom_out_buffer, -EINVAL);
719                                 break;
720                         }
721                         kgdb_contthread = thread;
722                 }
723                 strcpy(remcom_out_buffer, "OK");
724                 break;
725         }
726 }
727
728 /* Handle the 'T' thread query packets */
729 static void gdb_cmd_thread(struct kgdb_state *ks)
730 {
731         char *ptr = &remcom_in_buffer[1];
732         struct task_struct *thread;
733
734         kgdb_hex2long(&ptr, &ks->threadid);
735         thread = getthread(ks->linux_regs, ks->threadid);
736         if (thread)
737                 strcpy(remcom_out_buffer, "OK");
738         else
739                 error_packet(remcom_out_buffer, -EINVAL);
740 }
741
742 /* Handle the 'z' or 'Z' breakpoint remove or set packets */
743 static void gdb_cmd_break(struct kgdb_state *ks)
744 {
745         /*
746          * Since GDB-5.3, it's been drafted that '0' is a software
747          * breakpoint, '1' is a hardware breakpoint, so let's do that.
748          */
749         char *bpt_type = &remcom_in_buffer[1];
750         char *ptr = &remcom_in_buffer[2];
751         unsigned long addr;
752         unsigned long length;
753         int error = 0;
754
755         if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
756                 /* Unsupported */
757                 if (*bpt_type > '4')
758                         return;
759         } else {
760                 if (*bpt_type != '0' && *bpt_type != '1')
761                         /* Unsupported. */
762                         return;
763         }
764
765         /*
766          * Test if this is a hardware breakpoint, and
767          * if we support it:
768          */
769         if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
770                 /* Unsupported. */
771                 return;
772
773         if (*(ptr++) != ',') {
774                 error_packet(remcom_out_buffer, -EINVAL);
775                 return;
776         }
777         if (!kgdb_hex2long(&ptr, &addr)) {
778                 error_packet(remcom_out_buffer, -EINVAL);
779                 return;
780         }
781         if (*(ptr++) != ',' ||
782                 !kgdb_hex2long(&ptr, &length)) {
783                 error_packet(remcom_out_buffer, -EINVAL);
784                 return;
785         }
786
787         if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
788                 error = dbg_set_sw_break(addr);
789         else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
790                 error = dbg_remove_sw_break(addr);
791         else if (remcom_in_buffer[0] == 'Z')
792                 error = arch_kgdb_ops.set_hw_breakpoint(addr,
793                         (int)length, *bpt_type - '0');
794         else if (remcom_in_buffer[0] == 'z')
795                 error = arch_kgdb_ops.remove_hw_breakpoint(addr,
796                         (int) length, *bpt_type - '0');
797
798         if (error == 0)
799                 strcpy(remcom_out_buffer, "OK");
800         else
801                 error_packet(remcom_out_buffer, error);
802 }
803
804 /* Handle the 'C' signal / exception passing packets */
805 static int gdb_cmd_exception_pass(struct kgdb_state *ks)
806 {
807         /* C09 == pass exception
808          * C15 == detach kgdb, pass exception
809          */
810         if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
811
812                 ks->pass_exception = 1;
813                 remcom_in_buffer[0] = 'c';
814
815         } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
816
817                 ks->pass_exception = 1;
818                 remcom_in_buffer[0] = 'D';
819                 dbg_remove_all_break();
820                 kgdb_connected = 0;
821                 return 1;
822
823         } else {
824                 gdbstub_msg_write("KGDB only knows signal 9 (pass)"
825                         " and 15 (pass and disconnect)\n"
826                         "Executing a continue without signal passing\n", 0);
827                 remcom_in_buffer[0] = 'c';
828         }
829
830         /* Indicate fall through */
831         return -1;
832 }
833
834 /*
835  * This function performs all gdbserial command procesing
836  */
837 int gdb_serial_stub(struct kgdb_state *ks)
838 {
839         int error = 0;
840         int tmp;
841
842         /* Clear the out buffer. */
843         memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
844
845         if (kgdb_connected) {
846                 unsigned char thref[8];
847                 char *ptr;
848
849                 /* Reply to host that an exception has occurred */
850                 ptr = remcom_out_buffer;
851                 *ptr++ = 'T';
852                 ptr = pack_hex_byte(ptr, ks->signo);
853                 ptr += strlen(strcpy(ptr, "thread:"));
854                 int_to_threadref(thref, shadow_pid(current->pid));
855                 ptr = pack_threadid(ptr, thref);
856                 *ptr++ = ';';
857                 put_packet(remcom_out_buffer);
858         }
859
860         kgdb_usethread = kgdb_info[ks->cpu].task;
861         ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
862         ks->pass_exception = 0;
863
864         while (1) {
865                 error = 0;
866
867                 /* Clear the out buffer. */
868                 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
869
870                 get_packet(remcom_in_buffer);
871
872                 switch (remcom_in_buffer[0]) {
873                 case '?': /* gdbserial status */
874                         gdb_cmd_status(ks);
875                         break;
876                 case 'g': /* return the value of the CPU registers */
877                         gdb_cmd_getregs(ks);
878                         break;
879                 case 'G': /* set the value of the CPU registers - return OK */
880                         gdb_cmd_setregs(ks);
881                         break;
882                 case 'm': /* mAA..AA,LLLL  Read LLLL bytes at address AA..AA */
883                         gdb_cmd_memread(ks);
884                         break;
885                 case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
886                         gdb_cmd_memwrite(ks);
887                         break;
888                 case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
889                         gdb_cmd_binwrite(ks);
890                         break;
891                         /* kill or detach. KGDB should treat this like a
892                          * continue.
893                          */
894                 case 'D': /* Debugger detach */
895                 case 'k': /* Debugger detach via kill */
896                         gdb_cmd_detachkill(ks);
897                         goto default_handle;
898                 case 'R': /* Reboot */
899                         if (gdb_cmd_reboot(ks))
900                                 goto default_handle;
901                         break;
902                 case 'q': /* query command */
903                         gdb_cmd_query(ks);
904                         break;
905                 case 'H': /* task related */
906                         gdb_cmd_task(ks);
907                         break;
908                 case 'T': /* Query thread status */
909                         gdb_cmd_thread(ks);
910                         break;
911                 case 'z': /* Break point remove */
912                 case 'Z': /* Break point set */
913                         gdb_cmd_break(ks);
914                         break;
915 #ifdef CONFIG_KGDB_KDB
916                 case '3': /* Escape into back into kdb */
917                         if (remcom_in_buffer[1] == '\0') {
918                                 gdb_cmd_detachkill(ks);
919                                 return DBG_PASS_EVENT;
920                         }
921 #endif
922                 case 'C': /* Exception passing */
923                         tmp = gdb_cmd_exception_pass(ks);
924                         if (tmp > 0)
925                                 goto default_handle;
926                         if (tmp == 0)
927                                 break;
928                         /* Fall through on tmp < 0 */
929                 case 'c': /* Continue packet */
930                 case 's': /* Single step packet */
931                         if (kgdb_contthread && kgdb_contthread != current) {
932                                 /* Can't switch threads in kgdb */
933                                 error_packet(remcom_out_buffer, -EINVAL);
934                                 break;
935                         }
936                         dbg_activate_sw_breakpoints();
937                         /* Fall through to default processing */
938                 default:
939 default_handle:
940                         error = kgdb_arch_handle_exception(ks->ex_vector,
941                                                 ks->signo,
942                                                 ks->err_code,
943                                                 remcom_in_buffer,
944                                                 remcom_out_buffer,
945                                                 ks->linux_regs);
946                         /*
947                          * Leave cmd processing on error, detach,
948                          * kill, continue, or single step.
949                          */
950                         if (error >= 0 || remcom_in_buffer[0] == 'D' ||
951                             remcom_in_buffer[0] == 'k') {
952                                 error = 0;
953                                 goto kgdb_exit;
954                         }
955
956                 }
957
958                 /* reply to the request */
959                 put_packet(remcom_out_buffer);
960         }
961
962 kgdb_exit:
963         if (ks->pass_exception)
964                 error = 1;
965         return error;
966 }
967
968 int gdbstub_state(struct kgdb_state *ks, char *cmd)
969 {
970         int error;
971
972         switch (cmd[0]) {
973         case 'e':
974                 error = kgdb_arch_handle_exception(ks->ex_vector,
975                                                    ks->signo,
976                                                    ks->err_code,
977                                                    remcom_in_buffer,
978                                                    remcom_out_buffer,
979                                                    ks->linux_regs);
980                 return error;
981         case 's':
982         case 'c':
983                 strcpy(remcom_in_buffer, cmd);
984                 return 0;
985         case '?':
986                 gdb_cmd_status(ks);
987                 break;
988         case '\0':
989                 strcpy(remcom_out_buffer, "");
990                 break;
991         }
992         dbg_io_ops->write_char('+');
993         put_packet(remcom_out_buffer);
994         return 0;
995 }