kgdb: remove #include <linux/serial_8250.h> from kgdb.h
[~shefty/rdma-dev.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@ucw.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/serial_core.h>
35 #include <linux/reboot.h>
36 #include <linux/uaccess.h>
37 #include <asm/cacheflush.h>
38 #include <asm/unaligned.h>
39 #include "debug_core.h"
40
41 #define KGDB_MAX_THREAD_QUERY 17
42
43 /* Our I/O buffers. */
44 static char                     remcom_in_buffer[BUFMAX];
45 static char                     remcom_out_buffer[BUFMAX];
46 static int                      gdbstub_use_prev_in_buf;
47 static int                      gdbstub_prev_in_buf_pos;
48
49 /* Storage for the registers, in GDB format. */
50 static unsigned long            gdb_regs[(NUMREGBYTES +
51                                         sizeof(unsigned long) - 1) /
52                                         sizeof(unsigned long)];
53
54 /*
55  * GDB remote protocol parser:
56  */
57
58 #ifdef CONFIG_KGDB_KDB
59 static int gdbstub_read_wait(void)
60 {
61         int ret = -1;
62         int i;
63
64         if (unlikely(gdbstub_use_prev_in_buf)) {
65                 if (gdbstub_prev_in_buf_pos < gdbstub_use_prev_in_buf)
66                         return remcom_in_buffer[gdbstub_prev_in_buf_pos++];
67                 else
68                         gdbstub_use_prev_in_buf = 0;
69         }
70
71         /* poll any additional I/O interfaces that are defined */
72         while (ret < 0)
73                 for (i = 0; kdb_poll_funcs[i] != NULL; i++) {
74                         ret = kdb_poll_funcs[i]();
75                         if (ret > 0)
76                                 break;
77                 }
78         return ret;
79 }
80 #else
81 static int gdbstub_read_wait(void)
82 {
83         int ret = dbg_io_ops->read_char();
84         while (ret == NO_POLL_CHAR)
85                 ret = dbg_io_ops->read_char();
86         return ret;
87 }
88 #endif
89 /* scan for the sequence $<data>#<checksum> */
90 static void get_packet(char *buffer)
91 {
92         unsigned char checksum;
93         unsigned char xmitcsum;
94         int count;
95         char ch;
96
97         do {
98                 /*
99                  * Spin and wait around for the start character, ignore all
100                  * other characters:
101                  */
102                 while ((ch = (gdbstub_read_wait())) != '$')
103                         /* nothing */;
104
105                 kgdb_connected = 1;
106                 checksum = 0;
107                 xmitcsum = -1;
108
109                 count = 0;
110
111                 /*
112                  * now, read until a # or end of buffer is found:
113                  */
114                 while (count < (BUFMAX - 1)) {
115                         ch = gdbstub_read_wait();
116                         if (ch == '#')
117                                 break;
118                         checksum = checksum + ch;
119                         buffer[count] = ch;
120                         count = count + 1;
121                 }
122
123                 if (ch == '#') {
124                         xmitcsum = hex_to_bin(gdbstub_read_wait()) << 4;
125                         xmitcsum += hex_to_bin(gdbstub_read_wait());
126
127                         if (checksum != xmitcsum)
128                                 /* failed checksum */
129                                 dbg_io_ops->write_char('-');
130                         else
131                                 /* successful transfer */
132                                 dbg_io_ops->write_char('+');
133                         if (dbg_io_ops->flush)
134                                 dbg_io_ops->flush();
135                 }
136                 buffer[count] = 0;
137         } while (checksum != xmitcsum);
138 }
139
140 /*
141  * Send the packet in buffer.
142  * Check for gdb connection if asked for.
143  */
144 static void put_packet(char *buffer)
145 {
146         unsigned char checksum;
147         int count;
148         char ch;
149
150         /*
151          * $<packet info>#<checksum>.
152          */
153         while (1) {
154                 dbg_io_ops->write_char('$');
155                 checksum = 0;
156                 count = 0;
157
158                 while ((ch = buffer[count])) {
159                         dbg_io_ops->write_char(ch);
160                         checksum += ch;
161                         count++;
162                 }
163
164                 dbg_io_ops->write_char('#');
165                 dbg_io_ops->write_char(hex_asc_hi(checksum));
166                 dbg_io_ops->write_char(hex_asc_lo(checksum));
167                 if (dbg_io_ops->flush)
168                         dbg_io_ops->flush();
169
170                 /* Now see what we get in reply. */
171                 ch = gdbstub_read_wait();
172
173                 if (ch == 3)
174                         ch = gdbstub_read_wait();
175
176                 /* If we get an ACK, we are done. */
177                 if (ch == '+')
178                         return;
179
180                 /*
181                  * If we get the start of another packet, this means
182                  * that GDB is attempting to reconnect.  We will NAK
183                  * the packet being sent, and stop trying to send this
184                  * packet.
185                  */
186                 if (ch == '$') {
187                         dbg_io_ops->write_char('-');
188                         if (dbg_io_ops->flush)
189                                 dbg_io_ops->flush();
190                         return;
191                 }
192         }
193 }
194
195 static char gdbmsgbuf[BUFMAX + 1];
196
197 void gdbstub_msg_write(const char *s, int len)
198 {
199         char *bufptr;
200         int wcount;
201         int i;
202
203         if (len == 0)
204                 len = strlen(s);
205
206         /* 'O'utput */
207         gdbmsgbuf[0] = 'O';
208
209         /* Fill and send buffers... */
210         while (len > 0) {
211                 bufptr = gdbmsgbuf + 1;
212
213                 /* Calculate how many this time */
214                 if ((len << 1) > (BUFMAX - 2))
215                         wcount = (BUFMAX - 2) >> 1;
216                 else
217                         wcount = len;
218
219                 /* Pack in hex chars */
220                 for (i = 0; i < wcount; i++)
221                         bufptr = hex_byte_pack(bufptr, s[i]);
222                 *bufptr = '\0';
223
224                 /* Move up */
225                 s += wcount;
226                 len -= wcount;
227
228                 /* Write packet */
229                 put_packet(gdbmsgbuf);
230         }
231 }
232
233 /*
234  * Convert the memory pointed to by mem into hex, placing result in
235  * buf.  Return a pointer to the last char put in buf (null). May
236  * return an error.
237  */
238 char *kgdb_mem2hex(char *mem, char *buf, int count)
239 {
240         char *tmp;
241         int err;
242
243         /*
244          * We use the upper half of buf as an intermediate buffer for the
245          * raw memory copy.  Hex conversion will work against this one.
246          */
247         tmp = buf + count;
248
249         err = probe_kernel_read(tmp, mem, count);
250         if (err)
251                 return NULL;
252         while (count > 0) {
253                 buf = hex_byte_pack(buf, *tmp);
254                 tmp++;
255                 count--;
256         }
257         *buf = 0;
258
259         return buf;
260 }
261
262 /*
263  * Convert the hex array pointed to by buf into binary to be placed in
264  * mem.  Return a pointer to the character AFTER the last byte
265  * written.  May return an error.
266  */
267 int kgdb_hex2mem(char *buf, char *mem, int count)
268 {
269         char *tmp_raw;
270         char *tmp_hex;
271
272         /*
273          * We use the upper half of buf as an intermediate buffer for the
274          * raw memory that is converted from hex.
275          */
276         tmp_raw = buf + count * 2;
277
278         tmp_hex = tmp_raw - 1;
279         while (tmp_hex >= buf) {
280                 tmp_raw--;
281                 *tmp_raw = hex_to_bin(*tmp_hex--);
282                 *tmp_raw |= hex_to_bin(*tmp_hex--) << 4;
283         }
284
285         return probe_kernel_write(mem, tmp_raw, count);
286 }
287
288 /*
289  * While we find nice hex chars, build a long_val.
290  * Return number of chars processed.
291  */
292 int kgdb_hex2long(char **ptr, unsigned long *long_val)
293 {
294         int hex_val;
295         int num = 0;
296         int negate = 0;
297
298         *long_val = 0;
299
300         if (**ptr == '-') {
301                 negate = 1;
302                 (*ptr)++;
303         }
304         while (**ptr) {
305                 hex_val = hex_to_bin(**ptr);
306                 if (hex_val < 0)
307                         break;
308
309                 *long_val = (*long_val << 4) | hex_val;
310                 num++;
311                 (*ptr)++;
312         }
313
314         if (negate)
315                 *long_val = -*long_val;
316
317         return num;
318 }
319
320 /*
321  * Copy the binary array pointed to by buf into mem.  Fix $, #, and
322  * 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success.
323  * The input buf is overwitten with the result to write to mem.
324  */
325 static int kgdb_ebin2mem(char *buf, char *mem, int count)
326 {
327         int size = 0;
328         char *c = buf;
329
330         while (count-- > 0) {
331                 c[size] = *buf++;
332                 if (c[size] == 0x7d)
333                         c[size] = *buf++ ^ 0x20;
334                 size++;
335         }
336
337         return probe_kernel_write(mem, c, size);
338 }
339
340 #if DBG_MAX_REG_NUM > 0
341 void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
342 {
343         int i;
344         int idx = 0;
345         char *ptr = (char *)gdb_regs;
346
347         for (i = 0; i < DBG_MAX_REG_NUM; i++) {
348                 dbg_get_reg(i, ptr + idx, regs);
349                 idx += dbg_reg_def[i].size;
350         }
351 }
352
353 void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
354 {
355         int i;
356         int idx = 0;
357         char *ptr = (char *)gdb_regs;
358
359         for (i = 0; i < DBG_MAX_REG_NUM; i++) {
360                 dbg_set_reg(i, ptr + idx, regs);
361                 idx += dbg_reg_def[i].size;
362         }
363 }
364 #endif /* DBG_MAX_REG_NUM > 0 */
365
366 /* Write memory due to an 'M' or 'X' packet. */
367 static int write_mem_msg(int binary)
368 {
369         char *ptr = &remcom_in_buffer[1];
370         unsigned long addr;
371         unsigned long length;
372         int err;
373
374         if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
375             kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
376                 if (binary)
377                         err = kgdb_ebin2mem(ptr, (char *)addr, length);
378                 else
379                         err = kgdb_hex2mem(ptr, (char *)addr, length);
380                 if (err)
381                         return err;
382                 if (CACHE_FLUSH_IS_SAFE)
383                         flush_icache_range(addr, addr + length);
384                 return 0;
385         }
386
387         return -EINVAL;
388 }
389
390 static void error_packet(char *pkt, int error)
391 {
392         error = -error;
393         pkt[0] = 'E';
394         pkt[1] = hex_asc[(error / 10)];
395         pkt[2] = hex_asc[(error % 10)];
396         pkt[3] = '\0';
397 }
398
399 /*
400  * Thread ID accessors. We represent a flat TID space to GDB, where
401  * the per CPU idle threads (which under Linux all have PID 0) are
402  * remapped to negative TIDs.
403  */
404
405 #define BUF_THREAD_ID_SIZE      8
406
407 static char *pack_threadid(char *pkt, unsigned char *id)
408 {
409         unsigned char *limit;
410         int lzero = 1;
411
412         limit = id + (BUF_THREAD_ID_SIZE / 2);
413         while (id < limit) {
414                 if (!lzero || *id != 0) {
415                         pkt = hex_byte_pack(pkt, *id);
416                         lzero = 0;
417                 }
418                 id++;
419         }
420
421         if (lzero)
422                 pkt = hex_byte_pack(pkt, 0);
423
424         return pkt;
425 }
426
427 static void int_to_threadref(unsigned char *id, int value)
428 {
429         put_unaligned_be32(value, id);
430 }
431
432 static struct task_struct *getthread(struct pt_regs *regs, int tid)
433 {
434         /*
435          * Non-positive TIDs are remapped to the cpu shadow information
436          */
437         if (tid == 0 || tid == -1)
438                 tid = -atomic_read(&kgdb_active) - 2;
439         if (tid < -1 && tid > -NR_CPUS - 2) {
440                 if (kgdb_info[-tid - 2].task)
441                         return kgdb_info[-tid - 2].task;
442                 else
443                         return idle_task(-tid - 2);
444         }
445         if (tid <= 0) {
446                 printk(KERN_ERR "KGDB: Internal thread select error\n");
447                 dump_stack();
448                 return NULL;
449         }
450
451         /*
452          * find_task_by_pid_ns() does not take the tasklist lock anymore
453          * but is nicely RCU locked - hence is a pretty resilient
454          * thing to use:
455          */
456         return find_task_by_pid_ns(tid, &init_pid_ns);
457 }
458
459
460 /*
461  * Remap normal tasks to their real PID,
462  * CPU shadow threads are mapped to -CPU - 2
463  */
464 static inline int shadow_pid(int realpid)
465 {
466         if (realpid)
467                 return realpid;
468
469         return -raw_smp_processor_id() - 2;
470 }
471
472 /*
473  * All the functions that start with gdb_cmd are the various
474  * operations to implement the handlers for the gdbserial protocol
475  * where KGDB is communicating with an external debugger
476  */
477
478 /* Handle the '?' status packets */
479 static void gdb_cmd_status(struct kgdb_state *ks)
480 {
481         /*
482          * We know that this packet is only sent
483          * during initial connect.  So to be safe,
484          * we clear out our breakpoints now in case
485          * GDB is reconnecting.
486          */
487         dbg_remove_all_break();
488
489         remcom_out_buffer[0] = 'S';
490         hex_byte_pack(&remcom_out_buffer[1], ks->signo);
491 }
492
493 static void gdb_get_regs_helper(struct kgdb_state *ks)
494 {
495         struct task_struct *thread;
496         void *local_debuggerinfo;
497         int i;
498
499         thread = kgdb_usethread;
500         if (!thread) {
501                 thread = kgdb_info[ks->cpu].task;
502                 local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
503         } else {
504                 local_debuggerinfo = NULL;
505                 for_each_online_cpu(i) {
506                         /*
507                          * Try to find the task on some other
508                          * or possibly this node if we do not
509                          * find the matching task then we try
510                          * to approximate the results.
511                          */
512                         if (thread == kgdb_info[i].task)
513                                 local_debuggerinfo = kgdb_info[i].debuggerinfo;
514                 }
515         }
516
517         /*
518          * All threads that don't have debuggerinfo should be
519          * in schedule() sleeping, since all other CPUs
520          * are in kgdb_wait, and thus have debuggerinfo.
521          */
522         if (local_debuggerinfo) {
523                 pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
524         } else {
525                 /*
526                  * Pull stuff saved during switch_to; nothing
527                  * else is accessible (or even particularly
528                  * relevant).
529                  *
530                  * This should be enough for a stack trace.
531                  */
532                 sleeping_thread_to_gdb_regs(gdb_regs, thread);
533         }
534 }
535
536 /* Handle the 'g' get registers request */
537 static void gdb_cmd_getregs(struct kgdb_state *ks)
538 {
539         gdb_get_regs_helper(ks);
540         kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
541 }
542
543 /* Handle the 'G' set registers request */
544 static void gdb_cmd_setregs(struct kgdb_state *ks)
545 {
546         kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
547
548         if (kgdb_usethread && kgdb_usethread != current) {
549                 error_packet(remcom_out_buffer, -EINVAL);
550         } else {
551                 gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
552                 strcpy(remcom_out_buffer, "OK");
553         }
554 }
555
556 /* Handle the 'm' memory read bytes */
557 static void gdb_cmd_memread(struct kgdb_state *ks)
558 {
559         char *ptr = &remcom_in_buffer[1];
560         unsigned long length;
561         unsigned long addr;
562         char *err;
563
564         if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
565                                         kgdb_hex2long(&ptr, &length) > 0) {
566                 err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
567                 if (!err)
568                         error_packet(remcom_out_buffer, -EINVAL);
569         } else {
570                 error_packet(remcom_out_buffer, -EINVAL);
571         }
572 }
573
574 /* Handle the 'M' memory write bytes */
575 static void gdb_cmd_memwrite(struct kgdb_state *ks)
576 {
577         int err = write_mem_msg(0);
578
579         if (err)
580                 error_packet(remcom_out_buffer, err);
581         else
582                 strcpy(remcom_out_buffer, "OK");
583 }
584
585 #if DBG_MAX_REG_NUM > 0
586 static char *gdb_hex_reg_helper(int regnum, char *out)
587 {
588         int i;
589         int offset = 0;
590
591         for (i = 0; i < regnum; i++)
592                 offset += dbg_reg_def[i].size;
593         return kgdb_mem2hex((char *)gdb_regs + offset, out,
594                             dbg_reg_def[i].size);
595 }
596
597 /* Handle the 'p' individual regster get */
598 static void gdb_cmd_reg_get(struct kgdb_state *ks)
599 {
600         unsigned long regnum;
601         char *ptr = &remcom_in_buffer[1];
602
603         kgdb_hex2long(&ptr, &regnum);
604         if (regnum >= DBG_MAX_REG_NUM) {
605                 error_packet(remcom_out_buffer, -EINVAL);
606                 return;
607         }
608         gdb_get_regs_helper(ks);
609         gdb_hex_reg_helper(regnum, remcom_out_buffer);
610 }
611
612 /* Handle the 'P' individual regster set */
613 static void gdb_cmd_reg_set(struct kgdb_state *ks)
614 {
615         unsigned long regnum;
616         char *ptr = &remcom_in_buffer[1];
617         int i = 0;
618
619         kgdb_hex2long(&ptr, &regnum);
620         if (*ptr++ != '=' ||
621             !(!kgdb_usethread || kgdb_usethread == current) ||
622             !dbg_get_reg(regnum, gdb_regs, ks->linux_regs)) {
623                 error_packet(remcom_out_buffer, -EINVAL);
624                 return;
625         }
626         memset(gdb_regs, 0, sizeof(gdb_regs));
627         while (i < sizeof(gdb_regs) * 2)
628                 if (hex_to_bin(ptr[i]) >= 0)
629                         i++;
630                 else
631                         break;
632         i = i / 2;
633         kgdb_hex2mem(ptr, (char *)gdb_regs, i);
634         dbg_set_reg(regnum, gdb_regs, ks->linux_regs);
635         strcpy(remcom_out_buffer, "OK");
636 }
637 #endif /* DBG_MAX_REG_NUM > 0 */
638
639 /* Handle the 'X' memory binary write bytes */
640 static void gdb_cmd_binwrite(struct kgdb_state *ks)
641 {
642         int err = write_mem_msg(1);
643
644         if (err)
645                 error_packet(remcom_out_buffer, err);
646         else
647                 strcpy(remcom_out_buffer, "OK");
648 }
649
650 /* Handle the 'D' or 'k', detach or kill packets */
651 static void gdb_cmd_detachkill(struct kgdb_state *ks)
652 {
653         int error;
654
655         /* The detach case */
656         if (remcom_in_buffer[0] == 'D') {
657                 error = dbg_remove_all_break();
658                 if (error < 0) {
659                         error_packet(remcom_out_buffer, error);
660                 } else {
661                         strcpy(remcom_out_buffer, "OK");
662                         kgdb_connected = 0;
663                 }
664                 put_packet(remcom_out_buffer);
665         } else {
666                 /*
667                  * Assume the kill case, with no exit code checking,
668                  * trying to force detach the debugger:
669                  */
670                 dbg_remove_all_break();
671                 kgdb_connected = 0;
672         }
673 }
674
675 /* Handle the 'R' reboot packets */
676 static int gdb_cmd_reboot(struct kgdb_state *ks)
677 {
678         /* For now, only honor R0 */
679         if (strcmp(remcom_in_buffer, "R0") == 0) {
680                 printk(KERN_CRIT "Executing emergency reboot\n");
681                 strcpy(remcom_out_buffer, "OK");
682                 put_packet(remcom_out_buffer);
683
684                 /*
685                  * Execution should not return from
686                  * machine_emergency_restart()
687                  */
688                 machine_emergency_restart();
689                 kgdb_connected = 0;
690
691                 return 1;
692         }
693         return 0;
694 }
695
696 /* Handle the 'q' query packets */
697 static void gdb_cmd_query(struct kgdb_state *ks)
698 {
699         struct task_struct *g;
700         struct task_struct *p;
701         unsigned char thref[BUF_THREAD_ID_SIZE];
702         char *ptr;
703         int i;
704         int cpu;
705         int finished = 0;
706
707         switch (remcom_in_buffer[1]) {
708         case 's':
709         case 'f':
710                 if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10))
711                         break;
712
713                 i = 0;
714                 remcom_out_buffer[0] = 'm';
715                 ptr = remcom_out_buffer + 1;
716                 if (remcom_in_buffer[1] == 'f') {
717                         /* Each cpu is a shadow thread */
718                         for_each_online_cpu(cpu) {
719                                 ks->thr_query = 0;
720                                 int_to_threadref(thref, -cpu - 2);
721                                 ptr = pack_threadid(ptr, thref);
722                                 *(ptr++) = ',';
723                                 i++;
724                         }
725                 }
726
727                 do_each_thread(g, p) {
728                         if (i >= ks->thr_query && !finished) {
729                                 int_to_threadref(thref, p->pid);
730                                 ptr = pack_threadid(ptr, thref);
731                                 *(ptr++) = ',';
732                                 ks->thr_query++;
733                                 if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0)
734                                         finished = 1;
735                         }
736                         i++;
737                 } while_each_thread(g, p);
738
739                 *(--ptr) = '\0';
740                 break;
741
742         case 'C':
743                 /* Current thread id */
744                 strcpy(remcom_out_buffer, "QC");
745                 ks->threadid = shadow_pid(current->pid);
746                 int_to_threadref(thref, ks->threadid);
747                 pack_threadid(remcom_out_buffer + 2, thref);
748                 break;
749         case 'T':
750                 if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16))
751                         break;
752
753                 ks->threadid = 0;
754                 ptr = remcom_in_buffer + 17;
755                 kgdb_hex2long(&ptr, &ks->threadid);
756                 if (!getthread(ks->linux_regs, ks->threadid)) {
757                         error_packet(remcom_out_buffer, -EINVAL);
758                         break;
759                 }
760                 if ((int)ks->threadid > 0) {
761                         kgdb_mem2hex(getthread(ks->linux_regs,
762                                         ks->threadid)->comm,
763                                         remcom_out_buffer, 16);
764                 } else {
765                         static char tmpstr[23 + BUF_THREAD_ID_SIZE];
766
767                         sprintf(tmpstr, "shadowCPU%d",
768                                         (int)(-ks->threadid - 2));
769                         kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
770                 }
771                 break;
772 #ifdef CONFIG_KGDB_KDB
773         case 'R':
774                 if (strncmp(remcom_in_buffer, "qRcmd,", 6) == 0) {
775                         int len = strlen(remcom_in_buffer + 6);
776
777                         if ((len % 2) != 0) {
778                                 strcpy(remcom_out_buffer, "E01");
779                                 break;
780                         }
781                         kgdb_hex2mem(remcom_in_buffer + 6,
782                                      remcom_out_buffer, len);
783                         len = len / 2;
784                         remcom_out_buffer[len++] = 0;
785
786                         kdb_parse(remcom_out_buffer);
787                         strcpy(remcom_out_buffer, "OK");
788                 }
789                 break;
790 #endif
791         }
792 }
793
794 /* Handle the 'H' task query packets */
795 static void gdb_cmd_task(struct kgdb_state *ks)
796 {
797         struct task_struct *thread;
798         char *ptr;
799
800         switch (remcom_in_buffer[1]) {
801         case 'g':
802                 ptr = &remcom_in_buffer[2];
803                 kgdb_hex2long(&ptr, &ks->threadid);
804                 thread = getthread(ks->linux_regs, ks->threadid);
805                 if (!thread && ks->threadid > 0) {
806                         error_packet(remcom_out_buffer, -EINVAL);
807                         break;
808                 }
809                 kgdb_usethread = thread;
810                 ks->kgdb_usethreadid = ks->threadid;
811                 strcpy(remcom_out_buffer, "OK");
812                 break;
813         case 'c':
814                 ptr = &remcom_in_buffer[2];
815                 kgdb_hex2long(&ptr, &ks->threadid);
816                 if (!ks->threadid) {
817                         kgdb_contthread = NULL;
818                 } else {
819                         thread = getthread(ks->linux_regs, ks->threadid);
820                         if (!thread && ks->threadid > 0) {
821                                 error_packet(remcom_out_buffer, -EINVAL);
822                                 break;
823                         }
824                         kgdb_contthread = thread;
825                 }
826                 strcpy(remcom_out_buffer, "OK");
827                 break;
828         }
829 }
830
831 /* Handle the 'T' thread query packets */
832 static void gdb_cmd_thread(struct kgdb_state *ks)
833 {
834         char *ptr = &remcom_in_buffer[1];
835         struct task_struct *thread;
836
837         kgdb_hex2long(&ptr, &ks->threadid);
838         thread = getthread(ks->linux_regs, ks->threadid);
839         if (thread)
840                 strcpy(remcom_out_buffer, "OK");
841         else
842                 error_packet(remcom_out_buffer, -EINVAL);
843 }
844
845 /* Handle the 'z' or 'Z' breakpoint remove or set packets */
846 static void gdb_cmd_break(struct kgdb_state *ks)
847 {
848         /*
849          * Since GDB-5.3, it's been drafted that '0' is a software
850          * breakpoint, '1' is a hardware breakpoint, so let's do that.
851          */
852         char *bpt_type = &remcom_in_buffer[1];
853         char *ptr = &remcom_in_buffer[2];
854         unsigned long addr;
855         unsigned long length;
856         int error = 0;
857
858         if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
859                 /* Unsupported */
860                 if (*bpt_type > '4')
861                         return;
862         } else {
863                 if (*bpt_type != '0' && *bpt_type != '1')
864                         /* Unsupported. */
865                         return;
866         }
867
868         /*
869          * Test if this is a hardware breakpoint, and
870          * if we support it:
871          */
872         if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
873                 /* Unsupported. */
874                 return;
875
876         if (*(ptr++) != ',') {
877                 error_packet(remcom_out_buffer, -EINVAL);
878                 return;
879         }
880         if (!kgdb_hex2long(&ptr, &addr)) {
881                 error_packet(remcom_out_buffer, -EINVAL);
882                 return;
883         }
884         if (*(ptr++) != ',' ||
885                 !kgdb_hex2long(&ptr, &length)) {
886                 error_packet(remcom_out_buffer, -EINVAL);
887                 return;
888         }
889
890         if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
891                 error = dbg_set_sw_break(addr);
892         else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
893                 error = dbg_remove_sw_break(addr);
894         else if (remcom_in_buffer[0] == 'Z')
895                 error = arch_kgdb_ops.set_hw_breakpoint(addr,
896                         (int)length, *bpt_type - '0');
897         else if (remcom_in_buffer[0] == 'z')
898                 error = arch_kgdb_ops.remove_hw_breakpoint(addr,
899                         (int) length, *bpt_type - '0');
900
901         if (error == 0)
902                 strcpy(remcom_out_buffer, "OK");
903         else
904                 error_packet(remcom_out_buffer, error);
905 }
906
907 /* Handle the 'C' signal / exception passing packets */
908 static int gdb_cmd_exception_pass(struct kgdb_state *ks)
909 {
910         /* C09 == pass exception
911          * C15 == detach kgdb, pass exception
912          */
913         if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
914
915                 ks->pass_exception = 1;
916                 remcom_in_buffer[0] = 'c';
917
918         } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
919
920                 ks->pass_exception = 1;
921                 remcom_in_buffer[0] = 'D';
922                 dbg_remove_all_break();
923                 kgdb_connected = 0;
924                 return 1;
925
926         } else {
927                 gdbstub_msg_write("KGDB only knows signal 9 (pass)"
928                         " and 15 (pass and disconnect)\n"
929                         "Executing a continue without signal passing\n", 0);
930                 remcom_in_buffer[0] = 'c';
931         }
932
933         /* Indicate fall through */
934         return -1;
935 }
936
937 /*
938  * This function performs all gdbserial command procesing
939  */
940 int gdb_serial_stub(struct kgdb_state *ks)
941 {
942         int error = 0;
943         int tmp;
944
945         /* Initialize comm buffer and globals. */
946         memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
947         kgdb_usethread = kgdb_info[ks->cpu].task;
948         ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
949         ks->pass_exception = 0;
950
951         if (kgdb_connected) {
952                 unsigned char thref[BUF_THREAD_ID_SIZE];
953                 char *ptr;
954
955                 /* Reply to host that an exception has occurred */
956                 ptr = remcom_out_buffer;
957                 *ptr++ = 'T';
958                 ptr = hex_byte_pack(ptr, ks->signo);
959                 ptr += strlen(strcpy(ptr, "thread:"));
960                 int_to_threadref(thref, shadow_pid(current->pid));
961                 ptr = pack_threadid(ptr, thref);
962                 *ptr++ = ';';
963                 put_packet(remcom_out_buffer);
964         }
965
966         while (1) {
967                 error = 0;
968
969                 /* Clear the out buffer. */
970                 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
971
972                 get_packet(remcom_in_buffer);
973
974                 switch (remcom_in_buffer[0]) {
975                 case '?': /* gdbserial status */
976                         gdb_cmd_status(ks);
977                         break;
978                 case 'g': /* return the value of the CPU registers */
979                         gdb_cmd_getregs(ks);
980                         break;
981                 case 'G': /* set the value of the CPU registers - return OK */
982                         gdb_cmd_setregs(ks);
983                         break;
984                 case 'm': /* mAA..AA,LLLL  Read LLLL bytes at address AA..AA */
985                         gdb_cmd_memread(ks);
986                         break;
987                 case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
988                         gdb_cmd_memwrite(ks);
989                         break;
990 #if DBG_MAX_REG_NUM > 0
991                 case 'p': /* pXX Return gdb register XX (in hex) */
992                         gdb_cmd_reg_get(ks);
993                         break;
994                 case 'P': /* PXX=aaaa Set gdb register XX to aaaa (in hex) */
995                         gdb_cmd_reg_set(ks);
996                         break;
997 #endif /* DBG_MAX_REG_NUM > 0 */
998                 case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
999                         gdb_cmd_binwrite(ks);
1000                         break;
1001                         /* kill or detach. KGDB should treat this like a
1002                          * continue.
1003                          */
1004                 case 'D': /* Debugger detach */
1005                 case 'k': /* Debugger detach via kill */
1006                         gdb_cmd_detachkill(ks);
1007                         goto default_handle;
1008                 case 'R': /* Reboot */
1009                         if (gdb_cmd_reboot(ks))
1010                                 goto default_handle;
1011                         break;
1012                 case 'q': /* query command */
1013                         gdb_cmd_query(ks);
1014                         break;
1015                 case 'H': /* task related */
1016                         gdb_cmd_task(ks);
1017                         break;
1018                 case 'T': /* Query thread status */
1019                         gdb_cmd_thread(ks);
1020                         break;
1021                 case 'z': /* Break point remove */
1022                 case 'Z': /* Break point set */
1023                         gdb_cmd_break(ks);
1024                         break;
1025 #ifdef CONFIG_KGDB_KDB
1026                 case '3': /* Escape into back into kdb */
1027                         if (remcom_in_buffer[1] == '\0') {
1028                                 gdb_cmd_detachkill(ks);
1029                                 return DBG_PASS_EVENT;
1030                         }
1031 #endif
1032                 case 'C': /* Exception passing */
1033                         tmp = gdb_cmd_exception_pass(ks);
1034                         if (tmp > 0)
1035                                 goto default_handle;
1036                         if (tmp == 0)
1037                                 break;
1038                         /* Fall through on tmp < 0 */
1039                 case 'c': /* Continue packet */
1040                 case 's': /* Single step packet */
1041                         if (kgdb_contthread && kgdb_contthread != current) {
1042                                 /* Can't switch threads in kgdb */
1043                                 error_packet(remcom_out_buffer, -EINVAL);
1044                                 break;
1045                         }
1046                         dbg_activate_sw_breakpoints();
1047                         /* Fall through to default processing */
1048                 default:
1049 default_handle:
1050                         error = kgdb_arch_handle_exception(ks->ex_vector,
1051                                                 ks->signo,
1052                                                 ks->err_code,
1053                                                 remcom_in_buffer,
1054                                                 remcom_out_buffer,
1055                                                 ks->linux_regs);
1056                         /*
1057                          * Leave cmd processing on error, detach,
1058                          * kill, continue, or single step.
1059                          */
1060                         if (error >= 0 || remcom_in_buffer[0] == 'D' ||
1061                             remcom_in_buffer[0] == 'k') {
1062                                 error = 0;
1063                                 goto kgdb_exit;
1064                         }
1065
1066                 }
1067
1068                 /* reply to the request */
1069                 put_packet(remcom_out_buffer);
1070         }
1071
1072 kgdb_exit:
1073         if (ks->pass_exception)
1074                 error = 1;
1075         return error;
1076 }
1077
1078 int gdbstub_state(struct kgdb_state *ks, char *cmd)
1079 {
1080         int error;
1081
1082         switch (cmd[0]) {
1083         case 'e':
1084                 error = kgdb_arch_handle_exception(ks->ex_vector,
1085                                                    ks->signo,
1086                                                    ks->err_code,
1087                                                    remcom_in_buffer,
1088                                                    remcom_out_buffer,
1089                                                    ks->linux_regs);
1090                 return error;
1091         case 's':
1092         case 'c':
1093                 strcpy(remcom_in_buffer, cmd);
1094                 return 0;
1095         case '$':
1096                 strcpy(remcom_in_buffer, cmd);
1097                 gdbstub_use_prev_in_buf = strlen(remcom_in_buffer);
1098                 gdbstub_prev_in_buf_pos = 0;
1099                 return 0;
1100         }
1101         dbg_io_ops->write_char('+');
1102         put_packet(remcom_out_buffer);
1103         return 0;
1104 }
1105
1106 /**
1107  * gdbstub_exit - Send an exit message to GDB
1108  * @status: The exit code to report.
1109  */
1110 void gdbstub_exit(int status)
1111 {
1112         unsigned char checksum, ch, buffer[3];
1113         int loop;
1114
1115         if (!kgdb_connected)
1116                 return;
1117         kgdb_connected = 0;
1118
1119         if (!dbg_io_ops || dbg_kdb_mode)
1120                 return;
1121
1122         buffer[0] = 'W';
1123         buffer[1] = hex_asc_hi(status);
1124         buffer[2] = hex_asc_lo(status);
1125
1126         dbg_io_ops->write_char('$');
1127         checksum = 0;
1128
1129         for (loop = 0; loop < 3; loop++) {
1130                 ch = buffer[loop];
1131                 checksum += ch;
1132                 dbg_io_ops->write_char(ch);
1133         }
1134
1135         dbg_io_ops->write_char('#');
1136         dbg_io_ops->write_char(hex_asc_hi(checksum));
1137         dbg_io_ops->write_char(hex_asc_lo(checksum));
1138
1139         /* make sure the output is flushed, lest the bootloader clobber it */
1140         if (dbg_io_ops->flush)
1141                 dbg_io_ops->flush();
1142 }