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