4ef9dddf4588a33196104e079292fb1b3198948d
[linux-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 char *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                 return NULL;
242         while (count > 0) {
243                 buf = pack_hex_byte(buf, *tmp);
244                 tmp++;
245                 count--;
246         }
247         *buf = 0;
248
249         return buf;
250 }
251
252 /*
253  * Convert the hex array pointed to by buf into binary to be placed in
254  * mem.  Return a pointer to the character AFTER the last byte
255  * written.  May return an error.
256  */
257 int kgdb_hex2mem(char *buf, char *mem, int count)
258 {
259         char *tmp_raw;
260         char *tmp_hex;
261
262         /*
263          * We use the upper half of buf as an intermediate buffer for the
264          * raw memory that is converted from hex.
265          */
266         tmp_raw = buf + count * 2;
267
268         tmp_hex = tmp_raw - 1;
269         while (tmp_hex >= buf) {
270                 tmp_raw--;
271                 *tmp_raw = hex_to_bin(*tmp_hex--);
272                 *tmp_raw |= hex_to_bin(*tmp_hex--) << 4;
273         }
274
275         return probe_kernel_write(mem, tmp_raw, count);
276 }
277
278 /*
279  * While we find nice hex chars, build a long_val.
280  * Return number of chars processed.
281  */
282 int kgdb_hex2long(char **ptr, unsigned long *long_val)
283 {
284         int hex_val;
285         int num = 0;
286         int negate = 0;
287
288         *long_val = 0;
289
290         if (**ptr == '-') {
291                 negate = 1;
292                 (*ptr)++;
293         }
294         while (**ptr) {
295                 hex_val = hex_to_bin(**ptr);
296                 if (hex_val < 0)
297                         break;
298
299                 *long_val = (*long_val << 4) | hex_val;
300                 num++;
301                 (*ptr)++;
302         }
303
304         if (negate)
305                 *long_val = -*long_val;
306
307         return num;
308 }
309
310 /*
311  * Copy the binary array pointed to by buf into mem.  Fix $, #, and
312  * 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success.
313  * The input buf is overwitten with the result to write to mem.
314  */
315 static int kgdb_ebin2mem(char *buf, char *mem, int count)
316 {
317         int size = 0;
318         char *c = buf;
319
320         while (count-- > 0) {
321                 c[size] = *buf++;
322                 if (c[size] == 0x7d)
323                         c[size] = *buf++ ^ 0x20;
324                 size++;
325         }
326
327         return probe_kernel_write(mem, c, size);
328 }
329
330 #if DBG_MAX_REG_NUM > 0
331 void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
332 {
333         int i;
334         int idx = 0;
335         char *ptr = (char *)gdb_regs;
336
337         for (i = 0; i < DBG_MAX_REG_NUM; i++) {
338                 dbg_get_reg(i, ptr + idx, regs);
339                 idx += dbg_reg_def[i].size;
340         }
341 }
342
343 void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
344 {
345         int i;
346         int idx = 0;
347         char *ptr = (char *)gdb_regs;
348
349         for (i = 0; i < DBG_MAX_REG_NUM; i++) {
350                 dbg_set_reg(i, ptr + idx, regs);
351                 idx += dbg_reg_def[i].size;
352         }
353 }
354 #endif /* DBG_MAX_REG_NUM > 0 */
355
356 /* Write memory due to an 'M' or 'X' packet. */
357 static int write_mem_msg(int binary)
358 {
359         char *ptr = &remcom_in_buffer[1];
360         unsigned long addr;
361         unsigned long length;
362         int err;
363
364         if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
365             kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
366                 if (binary)
367                         err = kgdb_ebin2mem(ptr, (char *)addr, length);
368                 else
369                         err = kgdb_hex2mem(ptr, (char *)addr, length);
370                 if (err)
371                         return err;
372                 if (CACHE_FLUSH_IS_SAFE)
373                         flush_icache_range(addr, addr + length);
374                 return 0;
375         }
376
377         return -EINVAL;
378 }
379
380 static void error_packet(char *pkt, int error)
381 {
382         error = -error;
383         pkt[0] = 'E';
384         pkt[1] = hex_asc[(error / 10)];
385         pkt[2] = hex_asc[(error % 10)];
386         pkt[3] = '\0';
387 }
388
389 /*
390  * Thread ID accessors. We represent a flat TID space to GDB, where
391  * the per CPU idle threads (which under Linux all have PID 0) are
392  * remapped to negative TIDs.
393  */
394
395 #define BUF_THREAD_ID_SIZE      8
396
397 static char *pack_threadid(char *pkt, unsigned char *id)
398 {
399         unsigned char *limit;
400         int lzero = 1;
401
402         limit = id + (BUF_THREAD_ID_SIZE / 2);
403         while (id < limit) {
404                 if (!lzero || *id != 0) {
405                         pkt = pack_hex_byte(pkt, *id);
406                         lzero = 0;
407                 }
408                 id++;
409         }
410
411         if (lzero)
412                 pkt = pack_hex_byte(pkt, 0);
413
414         return pkt;
415 }
416
417 static void int_to_threadref(unsigned char *id, int value)
418 {
419         put_unaligned_be32(value, id);
420 }
421
422 static struct task_struct *getthread(struct pt_regs *regs, int tid)
423 {
424         /*
425          * Non-positive TIDs are remapped to the cpu shadow information
426          */
427         if (tid == 0 || tid == -1)
428                 tid = -atomic_read(&kgdb_active) - 2;
429         if (tid < -1 && tid > -NR_CPUS - 2) {
430                 if (kgdb_info[-tid - 2].task)
431                         return kgdb_info[-tid - 2].task;
432                 else
433                         return idle_task(-tid - 2);
434         }
435         if (tid <= 0) {
436                 printk(KERN_ERR "KGDB: Internal thread select error\n");
437                 dump_stack();
438                 return NULL;
439         }
440
441         /*
442          * find_task_by_pid_ns() does not take the tasklist lock anymore
443          * but is nicely RCU locked - hence is a pretty resilient
444          * thing to use:
445          */
446         return find_task_by_pid_ns(tid, &init_pid_ns);
447 }
448
449
450 /*
451  * Remap normal tasks to their real PID,
452  * CPU shadow threads are mapped to -CPU - 2
453  */
454 static inline int shadow_pid(int realpid)
455 {
456         if (realpid)
457                 return realpid;
458
459         return -raw_smp_processor_id() - 2;
460 }
461
462 /*
463  * All the functions that start with gdb_cmd are the various
464  * operations to implement the handlers for the gdbserial protocol
465  * where KGDB is communicating with an external debugger
466  */
467
468 /* Handle the '?' status packets */
469 static void gdb_cmd_status(struct kgdb_state *ks)
470 {
471         /*
472          * We know that this packet is only sent
473          * during initial connect.  So to be safe,
474          * we clear out our breakpoints now in case
475          * GDB is reconnecting.
476          */
477         dbg_remove_all_break();
478
479         remcom_out_buffer[0] = 'S';
480         pack_hex_byte(&remcom_out_buffer[1], ks->signo);
481 }
482
483 static void gdb_get_regs_helper(struct kgdb_state *ks)
484 {
485         struct task_struct *thread;
486         void *local_debuggerinfo;
487         int i;
488
489         thread = kgdb_usethread;
490         if (!thread) {
491                 thread = kgdb_info[ks->cpu].task;
492                 local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
493         } else {
494                 local_debuggerinfo = NULL;
495                 for_each_online_cpu(i) {
496                         /*
497                          * Try to find the task on some other
498                          * or possibly this node if we do not
499                          * find the matching task then we try
500                          * to approximate the results.
501                          */
502                         if (thread == kgdb_info[i].task)
503                                 local_debuggerinfo = kgdb_info[i].debuggerinfo;
504                 }
505         }
506
507         /*
508          * All threads that don't have debuggerinfo should be
509          * in schedule() sleeping, since all other CPUs
510          * are in kgdb_wait, and thus have debuggerinfo.
511          */
512         if (local_debuggerinfo) {
513                 pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
514         } else {
515                 /*
516                  * Pull stuff saved during switch_to; nothing
517                  * else is accessible (or even particularly
518                  * relevant).
519                  *
520                  * This should be enough for a stack trace.
521                  */
522                 sleeping_thread_to_gdb_regs(gdb_regs, thread);
523         }
524 }
525
526 /* Handle the 'g' get registers request */
527 static void gdb_cmd_getregs(struct kgdb_state *ks)
528 {
529         gdb_get_regs_helper(ks);
530         kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
531 }
532
533 /* Handle the 'G' set registers request */
534 static void gdb_cmd_setregs(struct kgdb_state *ks)
535 {
536         kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
537
538         if (kgdb_usethread && kgdb_usethread != current) {
539                 error_packet(remcom_out_buffer, -EINVAL);
540         } else {
541                 gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
542                 strcpy(remcom_out_buffer, "OK");
543         }
544 }
545
546 /* Handle the 'm' memory read bytes */
547 static void gdb_cmd_memread(struct kgdb_state *ks)
548 {
549         char *ptr = &remcom_in_buffer[1];
550         unsigned long length;
551         unsigned long addr;
552         char *err;
553
554         if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
555                                         kgdb_hex2long(&ptr, &length) > 0) {
556                 err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
557                 if (!err)
558                         error_packet(remcom_out_buffer, -EINVAL);
559         } else {
560                 error_packet(remcom_out_buffer, -EINVAL);
561         }
562 }
563
564 /* Handle the 'M' memory write bytes */
565 static void gdb_cmd_memwrite(struct kgdb_state *ks)
566 {
567         int err = write_mem_msg(0);
568
569         if (err)
570                 error_packet(remcom_out_buffer, err);
571         else
572                 strcpy(remcom_out_buffer, "OK");
573 }
574
575 #if DBG_MAX_REG_NUM > 0
576 static char *gdb_hex_reg_helper(int regnum, char *out)
577 {
578         int i;
579         int offset = 0;
580
581         for (i = 0; i < regnum; i++)
582                 offset += dbg_reg_def[i].size;
583         return kgdb_mem2hex((char *)gdb_regs + offset, out,
584                             dbg_reg_def[i].size);
585 }
586
587 /* Handle the 'p' individual regster get */
588 static void gdb_cmd_reg_get(struct kgdb_state *ks)
589 {
590         unsigned long regnum;
591         char *ptr = &remcom_in_buffer[1];
592
593         kgdb_hex2long(&ptr, &regnum);
594         if (regnum >= DBG_MAX_REG_NUM) {
595                 error_packet(remcom_out_buffer, -EINVAL);
596                 return;
597         }
598         gdb_get_regs_helper(ks);
599         gdb_hex_reg_helper(regnum, remcom_out_buffer);
600 }
601
602 /* Handle the 'P' individual regster set */
603 static void gdb_cmd_reg_set(struct kgdb_state *ks)
604 {
605         unsigned long regnum;
606         char *ptr = &remcom_in_buffer[1];
607
608         kgdb_hex2long(&ptr, &regnum);
609         if (*ptr++ != '=' ||
610             !(!kgdb_usethread || kgdb_usethread == current) ||
611             !dbg_get_reg(regnum, gdb_regs, ks->linux_regs)) {
612                 error_packet(remcom_out_buffer, -EINVAL);
613                 return;
614         }
615         kgdb_hex2mem(ptr, (char *)gdb_regs, dbg_reg_def[regnum].size);
616         dbg_set_reg(regnum, gdb_regs, ks->linux_regs);
617         strcpy(remcom_out_buffer, "OK");
618 }
619 #endif /* DBG_MAX_REG_NUM > 0 */
620
621 /* Handle the 'X' memory binary write bytes */
622 static void gdb_cmd_binwrite(struct kgdb_state *ks)
623 {
624         int err = write_mem_msg(1);
625
626         if (err)
627                 error_packet(remcom_out_buffer, err);
628         else
629                 strcpy(remcom_out_buffer, "OK");
630 }
631
632 /* Handle the 'D' or 'k', detach or kill packets */
633 static void gdb_cmd_detachkill(struct kgdb_state *ks)
634 {
635         int error;
636
637         /* The detach case */
638         if (remcom_in_buffer[0] == 'D') {
639                 error = dbg_remove_all_break();
640                 if (error < 0) {
641                         error_packet(remcom_out_buffer, error);
642                 } else {
643                         strcpy(remcom_out_buffer, "OK");
644                         kgdb_connected = 0;
645                 }
646                 put_packet(remcom_out_buffer);
647         } else {
648                 /*
649                  * Assume the kill case, with no exit code checking,
650                  * trying to force detach the debugger:
651                  */
652                 dbg_remove_all_break();
653                 kgdb_connected = 0;
654         }
655 }
656
657 /* Handle the 'R' reboot packets */
658 static int gdb_cmd_reboot(struct kgdb_state *ks)
659 {
660         /* For now, only honor R0 */
661         if (strcmp(remcom_in_buffer, "R0") == 0) {
662                 printk(KERN_CRIT "Executing emergency reboot\n");
663                 strcpy(remcom_out_buffer, "OK");
664                 put_packet(remcom_out_buffer);
665
666                 /*
667                  * Execution should not return from
668                  * machine_emergency_restart()
669                  */
670                 machine_emergency_restart();
671                 kgdb_connected = 0;
672
673                 return 1;
674         }
675         return 0;
676 }
677
678 /* Handle the 'q' query packets */
679 static void gdb_cmd_query(struct kgdb_state *ks)
680 {
681         struct task_struct *g;
682         struct task_struct *p;
683         unsigned char thref[BUF_THREAD_ID_SIZE];
684         char *ptr;
685         int i;
686         int cpu;
687         int finished = 0;
688
689         switch (remcom_in_buffer[1]) {
690         case 's':
691         case 'f':
692                 if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10))
693                         break;
694
695                 i = 0;
696                 remcom_out_buffer[0] = 'm';
697                 ptr = remcom_out_buffer + 1;
698                 if (remcom_in_buffer[1] == 'f') {
699                         /* Each cpu is a shadow thread */
700                         for_each_online_cpu(cpu) {
701                                 ks->thr_query = 0;
702                                 int_to_threadref(thref, -cpu - 2);
703                                 ptr = pack_threadid(ptr, thref);
704                                 *(ptr++) = ',';
705                                 i++;
706                         }
707                 }
708
709                 do_each_thread(g, p) {
710                         if (i >= ks->thr_query && !finished) {
711                                 int_to_threadref(thref, p->pid);
712                                 ptr = pack_threadid(ptr, thref);
713                                 *(ptr++) = ',';
714                                 ks->thr_query++;
715                                 if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0)
716                                         finished = 1;
717                         }
718                         i++;
719                 } while_each_thread(g, p);
720
721                 *(--ptr) = '\0';
722                 break;
723
724         case 'C':
725                 /* Current thread id */
726                 strcpy(remcom_out_buffer, "QC");
727                 ks->threadid = shadow_pid(current->pid);
728                 int_to_threadref(thref, ks->threadid);
729                 pack_threadid(remcom_out_buffer + 2, thref);
730                 break;
731         case 'T':
732                 if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16))
733                         break;
734
735                 ks->threadid = 0;
736                 ptr = remcom_in_buffer + 17;
737                 kgdb_hex2long(&ptr, &ks->threadid);
738                 if (!getthread(ks->linux_regs, ks->threadid)) {
739                         error_packet(remcom_out_buffer, -EINVAL);
740                         break;
741                 }
742                 if ((int)ks->threadid > 0) {
743                         kgdb_mem2hex(getthread(ks->linux_regs,
744                                         ks->threadid)->comm,
745                                         remcom_out_buffer, 16);
746                 } else {
747                         static char tmpstr[23 + BUF_THREAD_ID_SIZE];
748
749                         sprintf(tmpstr, "shadowCPU%d",
750                                         (int)(-ks->threadid - 2));
751                         kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
752                 }
753                 break;
754 #ifdef CONFIG_KGDB_KDB
755         case 'R':
756                 if (strncmp(remcom_in_buffer, "qRcmd,", 6) == 0) {
757                         int len = strlen(remcom_in_buffer + 6);
758
759                         if ((len % 2) != 0) {
760                                 strcpy(remcom_out_buffer, "E01");
761                                 break;
762                         }
763                         kgdb_hex2mem(remcom_in_buffer + 6,
764                                      remcom_out_buffer, len);
765                         len = len / 2;
766                         remcom_out_buffer[len++] = 0;
767
768                         kdb_parse(remcom_out_buffer);
769                         strcpy(remcom_out_buffer, "OK");
770                 }
771                 break;
772 #endif
773         }
774 }
775
776 /* Handle the 'H' task query packets */
777 static void gdb_cmd_task(struct kgdb_state *ks)
778 {
779         struct task_struct *thread;
780         char *ptr;
781
782         switch (remcom_in_buffer[1]) {
783         case 'g':
784                 ptr = &remcom_in_buffer[2];
785                 kgdb_hex2long(&ptr, &ks->threadid);
786                 thread = getthread(ks->linux_regs, ks->threadid);
787                 if (!thread && ks->threadid > 0) {
788                         error_packet(remcom_out_buffer, -EINVAL);
789                         break;
790                 }
791                 kgdb_usethread = thread;
792                 ks->kgdb_usethreadid = ks->threadid;
793                 strcpy(remcom_out_buffer, "OK");
794                 break;
795         case 'c':
796                 ptr = &remcom_in_buffer[2];
797                 kgdb_hex2long(&ptr, &ks->threadid);
798                 if (!ks->threadid) {
799                         kgdb_contthread = NULL;
800                 } else {
801                         thread = getthread(ks->linux_regs, ks->threadid);
802                         if (!thread && ks->threadid > 0) {
803                                 error_packet(remcom_out_buffer, -EINVAL);
804                                 break;
805                         }
806                         kgdb_contthread = thread;
807                 }
808                 strcpy(remcom_out_buffer, "OK");
809                 break;
810         }
811 }
812
813 /* Handle the 'T' thread query packets */
814 static void gdb_cmd_thread(struct kgdb_state *ks)
815 {
816         char *ptr = &remcom_in_buffer[1];
817         struct task_struct *thread;
818
819         kgdb_hex2long(&ptr, &ks->threadid);
820         thread = getthread(ks->linux_regs, ks->threadid);
821         if (thread)
822                 strcpy(remcom_out_buffer, "OK");
823         else
824                 error_packet(remcom_out_buffer, -EINVAL);
825 }
826
827 /* Handle the 'z' or 'Z' breakpoint remove or set packets */
828 static void gdb_cmd_break(struct kgdb_state *ks)
829 {
830         /*
831          * Since GDB-5.3, it's been drafted that '0' is a software
832          * breakpoint, '1' is a hardware breakpoint, so let's do that.
833          */
834         char *bpt_type = &remcom_in_buffer[1];
835         char *ptr = &remcom_in_buffer[2];
836         unsigned long addr;
837         unsigned long length;
838         int error = 0;
839
840         if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
841                 /* Unsupported */
842                 if (*bpt_type > '4')
843                         return;
844         } else {
845                 if (*bpt_type != '0' && *bpt_type != '1')
846                         /* Unsupported. */
847                         return;
848         }
849
850         /*
851          * Test if this is a hardware breakpoint, and
852          * if we support it:
853          */
854         if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
855                 /* Unsupported. */
856                 return;
857
858         if (*(ptr++) != ',') {
859                 error_packet(remcom_out_buffer, -EINVAL);
860                 return;
861         }
862         if (!kgdb_hex2long(&ptr, &addr)) {
863                 error_packet(remcom_out_buffer, -EINVAL);
864                 return;
865         }
866         if (*(ptr++) != ',' ||
867                 !kgdb_hex2long(&ptr, &length)) {
868                 error_packet(remcom_out_buffer, -EINVAL);
869                 return;
870         }
871
872         if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
873                 error = dbg_set_sw_break(addr);
874         else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
875                 error = dbg_remove_sw_break(addr);
876         else if (remcom_in_buffer[0] == 'Z')
877                 error = arch_kgdb_ops.set_hw_breakpoint(addr,
878                         (int)length, *bpt_type - '0');
879         else if (remcom_in_buffer[0] == 'z')
880                 error = arch_kgdb_ops.remove_hw_breakpoint(addr,
881                         (int) length, *bpt_type - '0');
882
883         if (error == 0)
884                 strcpy(remcom_out_buffer, "OK");
885         else
886                 error_packet(remcom_out_buffer, error);
887 }
888
889 /* Handle the 'C' signal / exception passing packets */
890 static int gdb_cmd_exception_pass(struct kgdb_state *ks)
891 {
892         /* C09 == pass exception
893          * C15 == detach kgdb, pass exception
894          */
895         if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
896
897                 ks->pass_exception = 1;
898                 remcom_in_buffer[0] = 'c';
899
900         } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
901
902                 ks->pass_exception = 1;
903                 remcom_in_buffer[0] = 'D';
904                 dbg_remove_all_break();
905                 kgdb_connected = 0;
906                 return 1;
907
908         } else {
909                 gdbstub_msg_write("KGDB only knows signal 9 (pass)"
910                         " and 15 (pass and disconnect)\n"
911                         "Executing a continue without signal passing\n", 0);
912                 remcom_in_buffer[0] = 'c';
913         }
914
915         /* Indicate fall through */
916         return -1;
917 }
918
919 /*
920  * This function performs all gdbserial command procesing
921  */
922 int gdb_serial_stub(struct kgdb_state *ks)
923 {
924         int error = 0;
925         int tmp;
926
927         /* Initialize comm buffer and globals. */
928         memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
929         kgdb_usethread = kgdb_info[ks->cpu].task;
930         ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
931         ks->pass_exception = 0;
932
933         if (kgdb_connected) {
934                 unsigned char thref[BUF_THREAD_ID_SIZE];
935                 char *ptr;
936
937                 /* Reply to host that an exception has occurred */
938                 ptr = remcom_out_buffer;
939                 *ptr++ = 'T';
940                 ptr = pack_hex_byte(ptr, ks->signo);
941                 ptr += strlen(strcpy(ptr, "thread:"));
942                 int_to_threadref(thref, shadow_pid(current->pid));
943                 ptr = pack_threadid(ptr, thref);
944                 *ptr++ = ';';
945                 put_packet(remcom_out_buffer);
946         }
947
948         while (1) {
949                 error = 0;
950
951                 /* Clear the out buffer. */
952                 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
953
954                 get_packet(remcom_in_buffer);
955
956                 switch (remcom_in_buffer[0]) {
957                 case '?': /* gdbserial status */
958                         gdb_cmd_status(ks);
959                         break;
960                 case 'g': /* return the value of the CPU registers */
961                         gdb_cmd_getregs(ks);
962                         break;
963                 case 'G': /* set the value of the CPU registers - return OK */
964                         gdb_cmd_setregs(ks);
965                         break;
966                 case 'm': /* mAA..AA,LLLL  Read LLLL bytes at address AA..AA */
967                         gdb_cmd_memread(ks);
968                         break;
969                 case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
970                         gdb_cmd_memwrite(ks);
971                         break;
972 #if DBG_MAX_REG_NUM > 0
973                 case 'p': /* pXX Return gdb register XX (in hex) */
974                         gdb_cmd_reg_get(ks);
975                         break;
976                 case 'P': /* PXX=aaaa Set gdb register XX to aaaa (in hex) */
977                         gdb_cmd_reg_set(ks);
978                         break;
979 #endif /* DBG_MAX_REG_NUM > 0 */
980                 case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
981                         gdb_cmd_binwrite(ks);
982                         break;
983                         /* kill or detach. KGDB should treat this like a
984                          * continue.
985                          */
986                 case 'D': /* Debugger detach */
987                 case 'k': /* Debugger detach via kill */
988                         gdb_cmd_detachkill(ks);
989                         goto default_handle;
990                 case 'R': /* Reboot */
991                         if (gdb_cmd_reboot(ks))
992                                 goto default_handle;
993                         break;
994                 case 'q': /* query command */
995                         gdb_cmd_query(ks);
996                         break;
997                 case 'H': /* task related */
998                         gdb_cmd_task(ks);
999                         break;
1000                 case 'T': /* Query thread status */
1001                         gdb_cmd_thread(ks);
1002                         break;
1003                 case 'z': /* Break point remove */
1004                 case 'Z': /* Break point set */
1005                         gdb_cmd_break(ks);
1006                         break;
1007 #ifdef CONFIG_KGDB_KDB
1008                 case '3': /* Escape into back into kdb */
1009                         if (remcom_in_buffer[1] == '\0') {
1010                                 gdb_cmd_detachkill(ks);
1011                                 return DBG_PASS_EVENT;
1012                         }
1013 #endif
1014                 case 'C': /* Exception passing */
1015                         tmp = gdb_cmd_exception_pass(ks);
1016                         if (tmp > 0)
1017                                 goto default_handle;
1018                         if (tmp == 0)
1019                                 break;
1020                         /* Fall through on tmp < 0 */
1021                 case 'c': /* Continue packet */
1022                 case 's': /* Single step packet */
1023                         if (kgdb_contthread && kgdb_contthread != current) {
1024                                 /* Can't switch threads in kgdb */
1025                                 error_packet(remcom_out_buffer, -EINVAL);
1026                                 break;
1027                         }
1028                         dbg_activate_sw_breakpoints();
1029                         /* Fall through to default processing */
1030                 default:
1031 default_handle:
1032                         error = kgdb_arch_handle_exception(ks->ex_vector,
1033                                                 ks->signo,
1034                                                 ks->err_code,
1035                                                 remcom_in_buffer,
1036                                                 remcom_out_buffer,
1037                                                 ks->linux_regs);
1038                         /*
1039                          * Leave cmd processing on error, detach,
1040                          * kill, continue, or single step.
1041                          */
1042                         if (error >= 0 || remcom_in_buffer[0] == 'D' ||
1043                             remcom_in_buffer[0] == 'k') {
1044                                 error = 0;
1045                                 goto kgdb_exit;
1046                         }
1047
1048                 }
1049
1050                 /* reply to the request */
1051                 put_packet(remcom_out_buffer);
1052         }
1053
1054 kgdb_exit:
1055         if (ks->pass_exception)
1056                 error = 1;
1057         return error;
1058 }
1059
1060 int gdbstub_state(struct kgdb_state *ks, char *cmd)
1061 {
1062         int error;
1063
1064         switch (cmd[0]) {
1065         case 'e':
1066                 error = kgdb_arch_handle_exception(ks->ex_vector,
1067                                                    ks->signo,
1068                                                    ks->err_code,
1069                                                    remcom_in_buffer,
1070                                                    remcom_out_buffer,
1071                                                    ks->linux_regs);
1072                 return error;
1073         case 's':
1074         case 'c':
1075                 strcpy(remcom_in_buffer, cmd);
1076                 return 0;
1077         case '?':
1078                 gdb_cmd_status(ks);
1079                 break;
1080         case '\0':
1081                 strcpy(remcom_out_buffer, "");
1082                 break;
1083         }
1084         dbg_io_ops->write_char('+');
1085         put_packet(remcom_out_buffer);
1086         return 0;
1087 }