ARM: tegra3: initialize pll_a during boot
[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@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/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 static int                      gdbstub_use_prev_in_buf;
46 static int                      gdbstub_prev_in_buf_pos;
47
48 /* Storage for the registers, in GDB format. */
49 static unsigned long            gdb_regs[(NUMREGBYTES +
50                                         sizeof(unsigned long) - 1) /
51                                         sizeof(unsigned long)];
52
53 /*
54  * GDB remote protocol parser:
55  */
56
57 #ifdef CONFIG_KGDB_KDB
58 static int gdbstub_read_wait(void)
59 {
60         int ret = -1;
61         int i;
62
63         if (unlikely(gdbstub_use_prev_in_buf)) {
64                 if (gdbstub_prev_in_buf_pos < gdbstub_use_prev_in_buf)
65                         return remcom_in_buffer[gdbstub_prev_in_buf_pos++];
66                 else
67                         gdbstub_use_prev_in_buf = 0;
68         }
69
70         /* poll any additional I/O interfaces that are defined */
71         while (ret < 0)
72                 for (i = 0; kdb_poll_funcs[i] != NULL; i++) {
73                         ret = kdb_poll_funcs[i]();
74                         if (ret > 0)
75                                 break;
76                 }
77         return ret;
78 }
79 #else
80 static int gdbstub_read_wait(void)
81 {
82         int ret = dbg_io_ops->read_char();
83         while (ret == NO_POLL_CHAR)
84                 ret = dbg_io_ops->read_char();
85         return ret;
86 }
87 #endif
88 /* scan for the sequence $<data>#<checksum> */
89 static void get_packet(char *buffer)
90 {
91         unsigned char checksum;
92         unsigned char xmitcsum;
93         int count;
94         char ch;
95
96         do {
97                 /*
98                  * Spin and wait around for the start character, ignore all
99                  * other characters:
100                  */
101                 while ((ch = (gdbstub_read_wait())) != '$')
102                         /* nothing */;
103
104                 kgdb_connected = 1;
105                 checksum = 0;
106                 xmitcsum = -1;
107
108                 count = 0;
109
110                 /*
111                  * now, read until a # or end of buffer is found:
112                  */
113                 while (count < (BUFMAX - 1)) {
114                         ch = gdbstub_read_wait();
115                         if (ch == '#')
116                                 break;
117                         checksum = checksum + ch;
118                         buffer[count] = ch;
119                         count = count + 1;
120                 }
121
122                 if (ch == '#') {
123                         xmitcsum = hex_to_bin(gdbstub_read_wait()) << 4;
124                         xmitcsum += hex_to_bin(gdbstub_read_wait());
125
126                         if (checksum != xmitcsum)
127                                 /* failed checksum */
128                                 dbg_io_ops->write_char('-');
129                         else
130                                 /* successful transfer */
131                                 dbg_io_ops->write_char('+');
132                         if (dbg_io_ops->flush)
133                                 dbg_io_ops->flush();
134                 }
135                 buffer[count] = 0;
136         } while (checksum != xmitcsum);
137 }
138
139 /*
140  * Send the packet in buffer.
141  * Check for gdb connection if asked for.
142  */
143 static void put_packet(char *buffer)
144 {
145         unsigned char checksum;
146         int count;
147         char ch;
148
149         /*
150          * $<packet info>#<checksum>.
151          */
152         while (1) {
153                 dbg_io_ops->write_char('$');
154                 checksum = 0;
155                 count = 0;
156
157                 while ((ch = buffer[count])) {
158                         dbg_io_ops->write_char(ch);
159                         checksum += ch;
160                         count++;
161                 }
162
163                 dbg_io_ops->write_char('#');
164                 dbg_io_ops->write_char(hex_asc_hi(checksum));
165                 dbg_io_ops->write_char(hex_asc_lo(checksum));
166                 if (dbg_io_ops->flush)
167                         dbg_io_ops->flush();
168
169                 /* Now see what we get in reply. */
170                 ch = gdbstub_read_wait();
171
172                 if (ch == 3)
173                         ch = gdbstub_read_wait();
174
175                 /* If we get an ACK, we are done. */
176                 if (ch == '+')
177                         return;
178
179                 /*
180                  * If we get the start of another packet, this means
181                  * that GDB is attempting to reconnect.  We will NAK
182                  * the packet being sent, and stop trying to send this
183                  * packet.
184                  */
185                 if (ch == '$') {
186                         dbg_io_ops->write_char('-');
187                         if (dbg_io_ops->flush)
188                                 dbg_io_ops->flush();
189                         return;
190                 }
191         }
192 }
193
194 static char gdbmsgbuf[BUFMAX + 1];
195
196 void gdbstub_msg_write(const char *s, int len)
197 {
198         char *bufptr;
199         int wcount;
200         int i;
201
202         if (len == 0)
203                 len = strlen(s);
204
205         /* 'O'utput */
206         gdbmsgbuf[0] = 'O';
207
208         /* Fill and send buffers... */
209         while (len > 0) {
210                 bufptr = gdbmsgbuf + 1;
211
212                 /* Calculate how many this time */
213                 if ((len << 1) > (BUFMAX - 2))
214                         wcount = (BUFMAX - 2) >> 1;
215                 else
216                         wcount = len;
217
218                 /* Pack in hex chars */
219                 for (i = 0; i < wcount; i++)
220                         bufptr = pack_hex_byte(bufptr, s[i]);
221                 *bufptr = '\0';
222
223                 /* Move up */
224                 s += wcount;
225                 len -= wcount;
226
227                 /* Write packet */
228                 put_packet(gdbmsgbuf);
229         }
230 }
231
232 /*
233  * Convert the memory pointed to by mem into hex, placing result in
234  * buf.  Return a pointer to the last char put in buf (null). May
235  * return an error.
236  */
237 char *kgdb_mem2hex(char *mem, char *buf, int count)
238 {
239         char *tmp;
240         int err;
241
242         /*
243          * We use the upper half of buf as an intermediate buffer for the
244          * raw memory copy.  Hex conversion will work against this one.
245          */
246         tmp = buf + count;
247
248         err = probe_kernel_read(tmp, mem, count);
249         if (err)
250                 return NULL;
251         while (count > 0) {
252                 buf = pack_hex_byte(buf, *tmp);
253                 tmp++;
254                 count--;
255         }
256         *buf = 0;
257
258         return buf;
259 }
260
261 /*
262  * Convert the hex array pointed to by buf into binary to be placed in
263  * mem.  Return a pointer to the character AFTER the last byte
264  * written.  May return an error.
265  */
266 int kgdb_hex2mem(char *buf, char *mem, int count)
267 {
268         char *tmp_raw;
269         char *tmp_hex;
270
271         /*
272          * We use the upper half of buf as an intermediate buffer for the
273          * raw memory that is converted from hex.
274          */
275         tmp_raw = buf + count * 2;
276
277         tmp_hex = tmp_raw - 1;
278         while (tmp_hex >= buf) {
279                 tmp_raw--;
280                 *tmp_raw = hex_to_bin(*tmp_hex--);
281                 *tmp_raw |= hex_to_bin(*tmp_hex--) << 4;
282         }
283
284         return probe_kernel_write(mem, tmp_raw, count);
285 }
286
287 /*
288  * While we find nice hex chars, build a long_val.
289  * Return number of chars processed.
290  */
291 int kgdb_hex2long(char **ptr, unsigned long *long_val)
292 {
293         int hex_val;
294         int num = 0;
295         int negate = 0;
296
297         *long_val = 0;
298
299         if (**ptr == '-') {
300                 negate = 1;
301                 (*ptr)++;
302         }
303         while (**ptr) {
304                 hex_val = hex_to_bin(**ptr);
305                 if (hex_val < 0)
306                         break;
307
308                 *long_val = (*long_val << 4) | hex_val;
309                 num++;
310                 (*ptr)++;
311         }
312
313         if (negate)
314                 *long_val = -*long_val;
315
316         return num;
317 }
318
319 /*
320  * Copy the binary array pointed to by buf into mem.  Fix $, #, and
321  * 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success.
322  * The input buf is overwitten with the result to write to mem.
323  */
324 static int kgdb_ebin2mem(char *buf, char *mem, int count)
325 {
326         int size = 0;
327         char *c = buf;
328
329         while (count-- > 0) {
330                 c[size] = *buf++;
331                 if (c[size] == 0x7d)
332                         c[size] = *buf++ ^ 0x20;
333                 size++;
334         }
335
336         return probe_kernel_write(mem, c, size);
337 }
338
339 #if DBG_MAX_REG_NUM > 0
340 void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
341 {
342         int i;
343         int idx = 0;
344         char *ptr = (char *)gdb_regs;
345
346         for (i = 0; i < DBG_MAX_REG_NUM; i++) {
347                 dbg_get_reg(i, ptr + idx, regs);
348                 idx += dbg_reg_def[i].size;
349         }
350 }
351
352 void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
353 {
354         int i;
355         int idx = 0;
356         char *ptr = (char *)gdb_regs;
357
358         for (i = 0; i < DBG_MAX_REG_NUM; i++) {
359                 dbg_set_reg(i, ptr + idx, regs);
360                 idx += dbg_reg_def[i].size;
361         }
362 }
363 #endif /* DBG_MAX_REG_NUM > 0 */
364
365 /* Write memory due to an 'M' or 'X' packet. */
366 static int write_mem_msg(int binary)
367 {
368         char *ptr = &remcom_in_buffer[1];
369         unsigned long addr;
370         unsigned long length;
371         int err;
372
373         if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
374             kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
375                 if (binary)
376                         err = kgdb_ebin2mem(ptr, (char *)addr, length);
377                 else
378                         err = kgdb_hex2mem(ptr, (char *)addr, length);
379                 if (err)
380                         return err;
381                 if (CACHE_FLUSH_IS_SAFE)
382                         flush_icache_range(addr, addr + length);
383                 return 0;
384         }
385
386         return -EINVAL;
387 }
388
389 static void error_packet(char *pkt, int error)
390 {
391         error = -error;
392         pkt[0] = 'E';
393         pkt[1] = hex_asc[(error / 10)];
394         pkt[2] = hex_asc[(error % 10)];
395         pkt[3] = '\0';
396 }
397
398 /*
399  * Thread ID accessors. We represent a flat TID space to GDB, where
400  * the per CPU idle threads (which under Linux all have PID 0) are
401  * remapped to negative TIDs.
402  */
403
404 #define BUF_THREAD_ID_SIZE      8
405
406 static char *pack_threadid(char *pkt, unsigned char *id)
407 {
408         unsigned char *limit;
409         int lzero = 1;
410
411         limit = id + (BUF_THREAD_ID_SIZE / 2);
412         while (id < limit) {
413                 if (!lzero || *id != 0) {
414                         pkt = pack_hex_byte(pkt, *id);
415                         lzero = 0;
416                 }
417                 id++;
418         }
419
420         if (lzero)
421                 pkt = pack_hex_byte(pkt, 0);
422
423         return pkt;
424 }
425
426 static void int_to_threadref(unsigned char *id, int value)
427 {
428         put_unaligned_be32(value, id);
429 }
430
431 static struct task_struct *getthread(struct pt_regs *regs, int tid)
432 {
433         /*
434          * Non-positive TIDs are remapped to the cpu shadow information
435          */
436         if (tid == 0 || tid == -1)
437                 tid = -atomic_read(&kgdb_active) - 2;
438         if (tid < -1 && tid > -NR_CPUS - 2) {
439                 if (kgdb_info[-tid - 2].task)
440                         return kgdb_info[-tid - 2].task;
441                 else
442                         return idle_task(-tid - 2);
443         }
444         if (tid <= 0) {
445                 printk(KERN_ERR "KGDB: Internal thread select error\n");
446                 dump_stack();
447                 return NULL;
448         }
449
450         /*
451          * find_task_by_pid_ns() does not take the tasklist lock anymore
452          * but is nicely RCU locked - hence is a pretty resilient
453          * thing to use:
454          */
455         return find_task_by_pid_ns(tid, &init_pid_ns);
456 }
457
458
459 /*
460  * Remap normal tasks to their real PID,
461  * CPU shadow threads are mapped to -CPU - 2
462  */
463 static inline int shadow_pid(int realpid)
464 {
465         if (realpid)
466                 return realpid;
467
468         return -raw_smp_processor_id() - 2;
469 }
470
471 /*
472  * All the functions that start with gdb_cmd are the various
473  * operations to implement the handlers for the gdbserial protocol
474  * where KGDB is communicating with an external debugger
475  */
476
477 /* Handle the '?' status packets */
478 static void gdb_cmd_status(struct kgdb_state *ks)
479 {
480         /*
481          * We know that this packet is only sent
482          * during initial connect.  So to be safe,
483          * we clear out our breakpoints now in case
484          * GDB is reconnecting.
485          */
486         dbg_remove_all_break();
487
488         remcom_out_buffer[0] = 'S';
489         pack_hex_byte(&remcom_out_buffer[1], ks->signo);
490 }
491
492 static void gdb_get_regs_helper(struct kgdb_state *ks)
493 {
494         struct task_struct *thread;
495         void *local_debuggerinfo;
496         int i;
497
498         thread = kgdb_usethread;
499         if (!thread) {
500                 thread = kgdb_info[ks->cpu].task;
501                 local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
502         } else {
503                 local_debuggerinfo = NULL;
504                 for_each_online_cpu(i) {
505                         /*
506                          * Try to find the task on some other
507                          * or possibly this node if we do not
508                          * find the matching task then we try
509                          * to approximate the results.
510                          */
511                         if (thread == kgdb_info[i].task)
512                                 local_debuggerinfo = kgdb_info[i].debuggerinfo;
513                 }
514         }
515
516         /*
517          * All threads that don't have debuggerinfo should be
518          * in schedule() sleeping, since all other CPUs
519          * are in kgdb_wait, and thus have debuggerinfo.
520          */
521         if (local_debuggerinfo) {
522                 pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
523         } else {
524                 /*
525                  * Pull stuff saved during switch_to; nothing
526                  * else is accessible (or even particularly
527                  * relevant).
528                  *
529                  * This should be enough for a stack trace.
530                  */
531                 sleeping_thread_to_gdb_regs(gdb_regs, thread);
532         }
533 }
534
535 /* Handle the 'g' get registers request */
536 static void gdb_cmd_getregs(struct kgdb_state *ks)
537 {
538         gdb_get_regs_helper(ks);
539         kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
540 }
541
542 /* Handle the 'G' set registers request */
543 static void gdb_cmd_setregs(struct kgdb_state *ks)
544 {
545         kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
546
547         if (kgdb_usethread && kgdb_usethread != current) {
548                 error_packet(remcom_out_buffer, -EINVAL);
549         } else {
550                 gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
551                 strcpy(remcom_out_buffer, "OK");
552         }
553 }
554
555 /* Handle the 'm' memory read bytes */
556 static void gdb_cmd_memread(struct kgdb_state *ks)
557 {
558         char *ptr = &remcom_in_buffer[1];
559         unsigned long length;
560         unsigned long addr;
561         char *err;
562
563         if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
564                                         kgdb_hex2long(&ptr, &length) > 0) {
565                 err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
566                 if (!err)
567                         error_packet(remcom_out_buffer, -EINVAL);
568         } else {
569                 error_packet(remcom_out_buffer, -EINVAL);
570         }
571 }
572
573 /* Handle the 'M' memory write bytes */
574 static void gdb_cmd_memwrite(struct kgdb_state *ks)
575 {
576         int err = write_mem_msg(0);
577
578         if (err)
579                 error_packet(remcom_out_buffer, err);
580         else
581                 strcpy(remcom_out_buffer, "OK");
582 }
583
584 #if DBG_MAX_REG_NUM > 0
585 static char *gdb_hex_reg_helper(int regnum, char *out)
586 {
587         int i;
588         int offset = 0;
589
590         for (i = 0; i < regnum; i++)
591                 offset += dbg_reg_def[i].size;
592         return kgdb_mem2hex((char *)gdb_regs + offset, out,
593                             dbg_reg_def[i].size);
594 }
595
596 /* Handle the 'p' individual regster get */
597 static void gdb_cmd_reg_get(struct kgdb_state *ks)
598 {
599         unsigned long regnum;
600         char *ptr = &remcom_in_buffer[1];
601
602         kgdb_hex2long(&ptr, &regnum);
603         if (regnum >= DBG_MAX_REG_NUM) {
604                 error_packet(remcom_out_buffer, -EINVAL);
605                 return;
606         }
607         gdb_get_regs_helper(ks);
608         gdb_hex_reg_helper(regnum, remcom_out_buffer);
609 }
610
611 /* Handle the 'P' individual regster set */
612 static void gdb_cmd_reg_set(struct kgdb_state *ks)
613 {
614         unsigned long regnum;
615         char *ptr = &remcom_in_buffer[1];
616         int i = 0;
617
618         kgdb_hex2long(&ptr, &regnum);
619         if (*ptr++ != '=' ||
620             !(!kgdb_usethread || kgdb_usethread == current) ||
621             !dbg_get_reg(regnum, gdb_regs, ks->linux_regs)) {
622                 error_packet(remcom_out_buffer, -EINVAL);
623                 return;
624         }
625         memset(gdb_regs, 0, sizeof(gdb_regs));
626         while (i < sizeof(gdb_regs) * 2)
627                 if (hex_to_bin(ptr[i]) >= 0)
628                         i++;
629                 else
630                         break;
631         i = i / 2;
632         kgdb_hex2mem(ptr, (char *)gdb_regs, i);
633         dbg_set_reg(regnum, gdb_regs, ks->linux_regs);
634         strcpy(remcom_out_buffer, "OK");
635 }
636 #endif /* DBG_MAX_REG_NUM > 0 */
637
638 /* Handle the 'X' memory binary write bytes */
639 static void gdb_cmd_binwrite(struct kgdb_state *ks)
640 {
641         int err = write_mem_msg(1);
642
643         if (err)
644                 error_packet(remcom_out_buffer, err);
645         else
646                 strcpy(remcom_out_buffer, "OK");
647 }
648
649 /* Handle the 'D' or 'k', detach or kill packets */
650 static void gdb_cmd_detachkill(struct kgdb_state *ks)
651 {
652         int error;
653
654         /* The detach case */
655         if (remcom_in_buffer[0] == 'D') {
656                 error = dbg_remove_all_break();
657                 if (error < 0) {
658                         error_packet(remcom_out_buffer, error);
659                 } else {
660                         strcpy(remcom_out_buffer, "OK");
661                         kgdb_connected = 0;
662                 }
663                 put_packet(remcom_out_buffer);
664         } else {
665                 /*
666                  * Assume the kill case, with no exit code checking,
667                  * trying to force detach the debugger:
668                  */
669                 dbg_remove_all_break();
670                 kgdb_connected = 0;
671         }
672 }
673
674 /* Handle the 'R' reboot packets */
675 static int gdb_cmd_reboot(struct kgdb_state *ks)
676 {
677         /* For now, only honor R0 */
678         if (strcmp(remcom_in_buffer, "R0") == 0) {
679                 printk(KERN_CRIT "Executing emergency reboot\n");
680                 strcpy(remcom_out_buffer, "OK");
681                 put_packet(remcom_out_buffer);
682
683                 /*
684                  * Execution should not return from
685                  * machine_emergency_restart()
686                  */
687                 machine_emergency_restart();
688                 kgdb_connected = 0;
689
690                 return 1;
691         }
692         return 0;
693 }
694
695 /* Handle the 'q' query packets */
696 static void gdb_cmd_query(struct kgdb_state *ks)
697 {
698         struct task_struct *g;
699         struct task_struct *p;
700         unsigned char thref[BUF_THREAD_ID_SIZE];
701         char *ptr;
702         int i;
703         int cpu;
704         int finished = 0;
705
706         switch (remcom_in_buffer[1]) {
707         case 's':
708         case 'f':
709                 if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10))
710                         break;
711
712                 i = 0;
713                 remcom_out_buffer[0] = 'm';
714                 ptr = remcom_out_buffer + 1;
715                 if (remcom_in_buffer[1] == 'f') {
716                         /* Each cpu is a shadow thread */
717                         for_each_online_cpu(cpu) {
718                                 ks->thr_query = 0;
719                                 int_to_threadref(thref, -cpu - 2);
720                                 ptr = pack_threadid(ptr, thref);
721                                 *(ptr++) = ',';
722                                 i++;
723                         }
724                 }
725
726                 do_each_thread(g, p) {
727                         if (i >= ks->thr_query && !finished) {
728                                 int_to_threadref(thref, p->pid);
729                                 ptr = pack_threadid(ptr, thref);
730                                 *(ptr++) = ',';
731                                 ks->thr_query++;
732                                 if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0)
733                                         finished = 1;
734                         }
735                         i++;
736                 } while_each_thread(g, p);
737
738                 *(--ptr) = '\0';
739                 break;
740
741         case 'C':
742                 /* Current thread id */
743                 strcpy(remcom_out_buffer, "QC");
744                 ks->threadid = shadow_pid(current->pid);
745                 int_to_threadref(thref, ks->threadid);
746                 pack_threadid(remcom_out_buffer + 2, thref);
747                 break;
748         case 'T':
749                 if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16))
750                         break;
751
752                 ks->threadid = 0;
753                 ptr = remcom_in_buffer + 17;
754                 kgdb_hex2long(&ptr, &ks->threadid);
755                 if (!getthread(ks->linux_regs, ks->threadid)) {
756                         error_packet(remcom_out_buffer, -EINVAL);
757                         break;
758                 }
759                 if ((int)ks->threadid > 0) {
760                         kgdb_mem2hex(getthread(ks->linux_regs,
761                                         ks->threadid)->comm,
762                                         remcom_out_buffer, 16);
763                 } else {
764                         static char tmpstr[23 + BUF_THREAD_ID_SIZE];
765
766                         sprintf(tmpstr, "shadowCPU%d",
767                                         (int)(-ks->threadid - 2));
768                         kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
769                 }
770                 break;
771 #ifdef CONFIG_KGDB_KDB
772         case 'R':
773                 if (strncmp(remcom_in_buffer, "qRcmd,", 6) == 0) {
774                         int len = strlen(remcom_in_buffer + 6);
775
776                         if ((len % 2) != 0) {
777                                 strcpy(remcom_out_buffer, "E01");
778                                 break;
779                         }
780                         kgdb_hex2mem(remcom_in_buffer + 6,
781                                      remcom_out_buffer, len);
782                         len = len / 2;
783                         remcom_out_buffer[len++] = 0;
784
785                         kdb_parse(remcom_out_buffer);
786                         strcpy(remcom_out_buffer, "OK");
787                 }
788                 break;
789 #endif
790         }
791 }
792
793 /* Handle the 'H' task query packets */
794 static void gdb_cmd_task(struct kgdb_state *ks)
795 {
796         struct task_struct *thread;
797         char *ptr;
798
799         switch (remcom_in_buffer[1]) {
800         case 'g':
801                 ptr = &remcom_in_buffer[2];
802                 kgdb_hex2long(&ptr, &ks->threadid);
803                 thread = getthread(ks->linux_regs, ks->threadid);
804                 if (!thread && ks->threadid > 0) {
805                         error_packet(remcom_out_buffer, -EINVAL);
806                         break;
807                 }
808                 kgdb_usethread = thread;
809                 ks->kgdb_usethreadid = ks->threadid;
810                 strcpy(remcom_out_buffer, "OK");
811                 break;
812         case 'c':
813                 ptr = &remcom_in_buffer[2];
814                 kgdb_hex2long(&ptr, &ks->threadid);
815                 if (!ks->threadid) {
816                         kgdb_contthread = NULL;
817                 } else {
818                         thread = getthread(ks->linux_regs, ks->threadid);
819                         if (!thread && ks->threadid > 0) {
820                                 error_packet(remcom_out_buffer, -EINVAL);
821                                 break;
822                         }
823                         kgdb_contthread = thread;
824                 }
825                 strcpy(remcom_out_buffer, "OK");
826                 break;
827         }
828 }
829
830 /* Handle the 'T' thread query packets */
831 static void gdb_cmd_thread(struct kgdb_state *ks)
832 {
833         char *ptr = &remcom_in_buffer[1];
834         struct task_struct *thread;
835
836         kgdb_hex2long(&ptr, &ks->threadid);
837         thread = getthread(ks->linux_regs, ks->threadid);
838         if (thread)
839                 strcpy(remcom_out_buffer, "OK");
840         else
841                 error_packet(remcom_out_buffer, -EINVAL);
842 }
843
844 /* Handle the 'z' or 'Z' breakpoint remove or set packets */
845 static void gdb_cmd_break(struct kgdb_state *ks)
846 {
847         /*
848          * Since GDB-5.3, it's been drafted that '0' is a software
849          * breakpoint, '1' is a hardware breakpoint, so let's do that.
850          */
851         char *bpt_type = &remcom_in_buffer[1];
852         char *ptr = &remcom_in_buffer[2];
853         unsigned long addr;
854         unsigned long length;
855         int error = 0;
856
857         if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
858                 /* Unsupported */
859                 if (*bpt_type > '4')
860                         return;
861         } else {
862                 if (*bpt_type != '0' && *bpt_type != '1')
863                         /* Unsupported. */
864                         return;
865         }
866
867         /*
868          * Test if this is a hardware breakpoint, and
869          * if we support it:
870          */
871         if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
872                 /* Unsupported. */
873                 return;
874
875         if (*(ptr++) != ',') {
876                 error_packet(remcom_out_buffer, -EINVAL);
877                 return;
878         }
879         if (!kgdb_hex2long(&ptr, &addr)) {
880                 error_packet(remcom_out_buffer, -EINVAL);
881                 return;
882         }
883         if (*(ptr++) != ',' ||
884                 !kgdb_hex2long(&ptr, &length)) {
885                 error_packet(remcom_out_buffer, -EINVAL);
886                 return;
887         }
888
889         if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
890                 error = dbg_set_sw_break(addr);
891         else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
892                 error = dbg_remove_sw_break(addr);
893         else if (remcom_in_buffer[0] == 'Z')
894                 error = arch_kgdb_ops.set_hw_breakpoint(addr,
895                         (int)length, *bpt_type - '0');
896         else if (remcom_in_buffer[0] == 'z')
897                 error = arch_kgdb_ops.remove_hw_breakpoint(addr,
898                         (int) length, *bpt_type - '0');
899
900         if (error == 0)
901                 strcpy(remcom_out_buffer, "OK");
902         else
903                 error_packet(remcom_out_buffer, error);
904 }
905
906 /* Handle the 'C' signal / exception passing packets */
907 static int gdb_cmd_exception_pass(struct kgdb_state *ks)
908 {
909         /* C09 == pass exception
910          * C15 == detach kgdb, pass exception
911          */
912         if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
913
914                 ks->pass_exception = 1;
915                 remcom_in_buffer[0] = 'c';
916
917         } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
918
919                 ks->pass_exception = 1;
920                 remcom_in_buffer[0] = 'D';
921                 dbg_remove_all_break();
922                 kgdb_connected = 0;
923                 return 1;
924
925         } else {
926                 gdbstub_msg_write("KGDB only knows signal 9 (pass)"
927                         " and 15 (pass and disconnect)\n"
928                         "Executing a continue without signal passing\n", 0);
929                 remcom_in_buffer[0] = 'c';
930         }
931
932         /* Indicate fall through */
933         return -1;
934 }
935
936 /*
937  * This function performs all gdbserial command procesing
938  */
939 int gdb_serial_stub(struct kgdb_state *ks)
940 {
941         int error = 0;
942         int tmp;
943
944         /* Initialize comm buffer and globals. */
945         memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
946         kgdb_usethread = kgdb_info[ks->cpu].task;
947         ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
948         ks->pass_exception = 0;
949
950         if (kgdb_connected) {
951                 unsigned char thref[BUF_THREAD_ID_SIZE];
952                 char *ptr;
953
954                 /* Reply to host that an exception has occurred */
955                 ptr = remcom_out_buffer;
956                 *ptr++ = 'T';
957                 ptr = pack_hex_byte(ptr, ks->signo);
958                 ptr += strlen(strcpy(ptr, "thread:"));
959                 int_to_threadref(thref, shadow_pid(current->pid));
960                 ptr = pack_threadid(ptr, thref);
961                 *ptr++ = ';';
962                 put_packet(remcom_out_buffer);
963         }
964
965         while (1) {
966                 error = 0;
967
968                 /* Clear the out buffer. */
969                 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
970
971                 get_packet(remcom_in_buffer);
972
973                 switch (remcom_in_buffer[0]) {
974                 case '?': /* gdbserial status */
975                         gdb_cmd_status(ks);
976                         break;
977                 case 'g': /* return the value of the CPU registers */
978                         gdb_cmd_getregs(ks);
979                         break;
980                 case 'G': /* set the value of the CPU registers - return OK */
981                         gdb_cmd_setregs(ks);
982                         break;
983                 case 'm': /* mAA..AA,LLLL  Read LLLL bytes at address AA..AA */
984                         gdb_cmd_memread(ks);
985                         break;
986                 case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
987                         gdb_cmd_memwrite(ks);
988                         break;
989 #if DBG_MAX_REG_NUM > 0
990                 case 'p': /* pXX Return gdb register XX (in hex) */
991                         gdb_cmd_reg_get(ks);
992                         break;
993                 case 'P': /* PXX=aaaa Set gdb register XX to aaaa (in hex) */
994                         gdb_cmd_reg_set(ks);
995                         break;
996 #endif /* DBG_MAX_REG_NUM > 0 */
997                 case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
998                         gdb_cmd_binwrite(ks);
999                         break;
1000                         /* kill or detach. KGDB should treat this like a
1001                          * continue.
1002                          */
1003                 case 'D': /* Debugger detach */
1004                 case 'k': /* Debugger detach via kill */
1005                         gdb_cmd_detachkill(ks);
1006                         goto default_handle;
1007                 case 'R': /* Reboot */
1008                         if (gdb_cmd_reboot(ks))
1009                                 goto default_handle;
1010                         break;
1011                 case 'q': /* query command */
1012                         gdb_cmd_query(ks);
1013                         break;
1014                 case 'H': /* task related */
1015                         gdb_cmd_task(ks);
1016                         break;
1017                 case 'T': /* Query thread status */
1018                         gdb_cmd_thread(ks);
1019                         break;
1020                 case 'z': /* Break point remove */
1021                 case 'Z': /* Break point set */
1022                         gdb_cmd_break(ks);
1023                         break;
1024 #ifdef CONFIG_KGDB_KDB
1025                 case '3': /* Escape into back into kdb */
1026                         if (remcom_in_buffer[1] == '\0') {
1027                                 gdb_cmd_detachkill(ks);
1028                                 return DBG_PASS_EVENT;
1029                         }
1030 #endif
1031                 case 'C': /* Exception passing */
1032                         tmp = gdb_cmd_exception_pass(ks);
1033                         if (tmp > 0)
1034                                 goto default_handle;
1035                         if (tmp == 0)
1036                                 break;
1037                         /* Fall through on tmp < 0 */
1038                 case 'c': /* Continue packet */
1039                 case 's': /* Single step packet */
1040                         if (kgdb_contthread && kgdb_contthread != current) {
1041                                 /* Can't switch threads in kgdb */
1042                                 error_packet(remcom_out_buffer, -EINVAL);
1043                                 break;
1044                         }
1045                         dbg_activate_sw_breakpoints();
1046                         /* Fall through to default processing */
1047                 default:
1048 default_handle:
1049                         error = kgdb_arch_handle_exception(ks->ex_vector,
1050                                                 ks->signo,
1051                                                 ks->err_code,
1052                                                 remcom_in_buffer,
1053                                                 remcom_out_buffer,
1054                                                 ks->linux_regs);
1055                         /*
1056                          * Leave cmd processing on error, detach,
1057                          * kill, continue, or single step.
1058                          */
1059                         if (error >= 0 || remcom_in_buffer[0] == 'D' ||
1060                             remcom_in_buffer[0] == 'k') {
1061                                 error = 0;
1062                                 goto kgdb_exit;
1063                         }
1064
1065                 }
1066
1067                 /* reply to the request */
1068                 put_packet(remcom_out_buffer);
1069         }
1070
1071 kgdb_exit:
1072         if (ks->pass_exception)
1073                 error = 1;
1074         return error;
1075 }
1076
1077 int gdbstub_state(struct kgdb_state *ks, char *cmd)
1078 {
1079         int error;
1080
1081         switch (cmd[0]) {
1082         case 'e':
1083                 error = kgdb_arch_handle_exception(ks->ex_vector,
1084                                                    ks->signo,
1085                                                    ks->err_code,
1086                                                    remcom_in_buffer,
1087                                                    remcom_out_buffer,
1088                                                    ks->linux_regs);
1089                 return error;
1090         case 's':
1091         case 'c':
1092                 strcpy(remcom_in_buffer, cmd);
1093                 return 0;
1094         case '$':
1095                 strcpy(remcom_in_buffer, cmd);
1096                 gdbstub_use_prev_in_buf = strlen(remcom_in_buffer);
1097                 gdbstub_prev_in_buf_pos = 0;
1098                 return 0;
1099         }
1100         dbg_io_ops->write_char('+');
1101         put_packet(remcom_out_buffer);
1102         return 0;
1103 }
1104
1105 /**
1106  * gdbstub_exit - Send an exit message to GDB
1107  * @status: The exit code to report.
1108  */
1109 void gdbstub_exit(int status)
1110 {
1111         unsigned char checksum, ch, buffer[3];
1112         int loop;
1113
1114         buffer[0] = 'W';
1115         buffer[1] = hex_asc_hi(status);
1116         buffer[2] = hex_asc_lo(status);
1117
1118         dbg_io_ops->write_char('$');
1119         checksum = 0;
1120
1121         for (loop = 0; loop < 3; loop++) {
1122                 ch = buffer[loop];
1123                 checksum += ch;
1124                 dbg_io_ops->write_char(ch);
1125         }
1126
1127         dbg_io_ops->write_char('#');
1128         dbg_io_ops->write_char(hex_asc_hi(checksum));
1129         dbg_io_ops->write_char(hex_asc_lo(checksum));
1130
1131         /* make sure the output is flushed, lest the bootloader clobber it */
1132         dbg_io_ops->flush();
1133 }