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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/sched/signal.h>
33#include <linux/kgdb.h>
34#include <linux/kdb.h>
35#include <linux/serial_core.h>
36#include <linux/reboot.h>
37#include <linux/uaccess.h>
38#include <asm/cacheflush.h>
39#include <asm/unaligned.h>
40#include "debug_core.h"
41
42#define KGDB_MAX_THREAD_QUERY 17
43
44/* Our I/O buffers. */
45static char remcom_in_buffer[BUFMAX];
46static char remcom_out_buffer[BUFMAX];
47static int gdbstub_use_prev_in_buf;
48static int gdbstub_prev_in_buf_pos;
49
50/* Storage for the registers, in GDB format. */
51static unsigned long gdb_regs[(NUMREGBYTES +
52 sizeof(unsigned long) - 1) /
53 sizeof(unsigned long)];
54
55/*
56 * GDB remote protocol parser:
57 */
58
59#ifdef CONFIG_KGDB_KDB
60static int gdbstub_read_wait(void)
61{
62 int ret = -1;
63 int i;
64
65 if (unlikely(gdbstub_use_prev_in_buf)) {
66 if (gdbstub_prev_in_buf_pos < gdbstub_use_prev_in_buf)
67 return remcom_in_buffer[gdbstub_prev_in_buf_pos++];
68 else
69 gdbstub_use_prev_in_buf = 0;
70 }
71
72 /* poll any additional I/O interfaces that are defined */
73 while (ret < 0)
74 for (i = 0; kdb_poll_funcs[i] != NULL; i++) {
75 ret = kdb_poll_funcs[i]();
76 if (ret > 0)
77 break;
78 }
79 return ret;
80}
81#else
82static int gdbstub_read_wait(void)
83{
84 int ret = dbg_io_ops->read_char();
85 while (ret == NO_POLL_CHAR)
86 ret = dbg_io_ops->read_char();
87 return ret;
88}
89#endif
90/* scan for the sequence $<data>#<checksum> */
91static void get_packet(char *buffer)
92{
93 unsigned char checksum;
94 unsigned char xmitcsum;
95 int count;
96 char ch;
97
98 do {
99 /*
100 * Spin and wait around for the start character, ignore all
101 * other characters:
102 */
103 while ((ch = (gdbstub_read_wait())) != '$')
104 /* nothing */;
105
106 kgdb_connected = 1;
107 checksum = 0;
108 xmitcsum = -1;
109
110 count = 0;
111
112 /*
113 * now, read until a # or end of buffer is found:
114 */
115 while (count < (BUFMAX - 1)) {
116 ch = gdbstub_read_wait();
117 if (ch == '#')
118 break;
119 checksum = checksum + ch;
120 buffer[count] = ch;
121 count = count + 1;
122 }
123
124 if (ch == '#') {
125 xmitcsum = hex_to_bin(gdbstub_read_wait()) << 4;
126 xmitcsum += hex_to_bin(gdbstub_read_wait());
127
128 if (checksum != xmitcsum)
129 /* failed checksum */
130 dbg_io_ops->write_char('-');
131 else
132 /* successful transfer */
133 dbg_io_ops->write_char('+');
134 if (dbg_io_ops->flush)
135 dbg_io_ops->flush();
136 }
137 buffer[count] = 0;
138 } while (checksum != xmitcsum);
139}
140
141/*
142 * Send the packet in buffer.
143 * Check for gdb connection if asked for.
144 */
145static void put_packet(char *buffer)
146{
147 unsigned char checksum;
148 int count;
149 char ch;
150
151 /*
152 * $<packet info>#<checksum>.
153 */
154 while (1) {
155 dbg_io_ops->write_char('$');
156 checksum = 0;
157 count = 0;
158
159 while ((ch = buffer[count])) {
160 dbg_io_ops->write_char(ch);
161 checksum += ch;
162 count++;
163 }
164
165 dbg_io_ops->write_char('#');
166 dbg_io_ops->write_char(hex_asc_hi(checksum));
167 dbg_io_ops->write_char(hex_asc_lo(checksum));
168 if (dbg_io_ops->flush)
169 dbg_io_ops->flush();
170
171 /* Now see what we get in reply. */
172 ch = gdbstub_read_wait();
173
174 if (ch == 3)
175 ch = gdbstub_read_wait();
176
177 /* If we get an ACK, we are done. */
178 if (ch == '+')
179 return;
180
181 /*
182 * If we get the start of another packet, this means
183 * that GDB is attempting to reconnect. We will NAK
184 * the packet being sent, and stop trying to send this
185 * packet.
186 */
187 if (ch == '$') {
188 dbg_io_ops->write_char('-');
189 if (dbg_io_ops->flush)
190 dbg_io_ops->flush();
191 return;
192 }
193 }
194}
195
196static char gdbmsgbuf[BUFMAX + 1];
197
198void gdbstub_msg_write(const char *s, int len)
199{
200 char *bufptr;
201 int wcount;
202 int i;
203
204 if (len == 0)
205 len = strlen(s);
206
207 /* 'O'utput */
208 gdbmsgbuf[0] = 'O';
209
210 /* Fill and send buffers... */
211 while (len > 0) {
212 bufptr = gdbmsgbuf + 1;
213
214 /* Calculate how many this time */
215 if ((len << 1) > (BUFMAX - 2))
216 wcount = (BUFMAX - 2) >> 1;
217 else
218 wcount = len;
219
220 /* Pack in hex chars */
221 for (i = 0; i < wcount; i++)
222 bufptr = hex_byte_pack(bufptr, s[i]);
223 *bufptr = '\0';
224
225 /* Move up */
226 s += wcount;
227 len -= wcount;
228
229 /* Write packet */
230 put_packet(gdbmsgbuf);
231 }
232}
233
234/*
235 * Convert the memory pointed to by mem into hex, placing result in
236 * buf. Return a pointer to the last char put in buf (null). May
237 * return an error.
238 */
239char *kgdb_mem2hex(char *mem, char *buf, int count)
240{
241 char *tmp;
242 int err;
243
244 /*
245 * We use the upper half of buf as an intermediate buffer for the
246 * raw memory copy. Hex conversion will work against this one.
247 */
248 tmp = buf + count;
249
250 err = probe_kernel_read(tmp, mem, count);
251 if (err)
252 return NULL;
253 while (count > 0) {
254 buf = hex_byte_pack(buf, *tmp);
255 tmp++;
256 count--;
257 }
258 *buf = 0;
259
260 return buf;
261}
262
263/*
264 * Convert the hex array pointed to by buf into binary to be placed in
265 * mem. Return a pointer to the character AFTER the last byte
266 * written. May return an error.
267 */
268int kgdb_hex2mem(char *buf, char *mem, int count)
269{
270 char *tmp_raw;
271 char *tmp_hex;
272
273 /*
274 * We use the upper half of buf as an intermediate buffer for the
275 * raw memory that is converted from hex.
276 */
277 tmp_raw = buf + count * 2;
278
279 tmp_hex = tmp_raw - 1;
280 while (tmp_hex >= buf) {
281 tmp_raw--;
282 *tmp_raw = hex_to_bin(*tmp_hex--);
283 *tmp_raw |= hex_to_bin(*tmp_hex--) << 4;
284 }
285
286 return probe_kernel_write(mem, tmp_raw, count);
287}
288
289/*
290 * While we find nice hex chars, build a long_val.
291 * Return number of chars processed.
292 */
293int kgdb_hex2long(char **ptr, unsigned long *long_val)
294{
295 int hex_val;
296 int num = 0;
297 int negate = 0;
298
299 *long_val = 0;
300
301 if (**ptr == '-') {
302 negate = 1;
303 (*ptr)++;
304 }
305 while (**ptr) {
306 hex_val = hex_to_bin(**ptr);
307 if (hex_val < 0)
308 break;
309
310 *long_val = (*long_val << 4) | hex_val;
311 num++;
312 (*ptr)++;
313 }
314
315 if (negate)
316 *long_val = -*long_val;
317
318 return num;
319}
320
321/*
322 * Copy the binary array pointed to by buf into mem. Fix $, #, and
323 * 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success.
324 * The input buf is overwitten with the result to write to mem.
325 */
326static int kgdb_ebin2mem(char *buf, char *mem, int count)
327{
328 int size = 0;
329 char *c = buf;
330
331 while (count-- > 0) {
332 c[size] = *buf++;
333 if (c[size] == 0x7d)
334 c[size] = *buf++ ^ 0x20;
335 size++;
336 }
337
338 return probe_kernel_write(mem, c, size);
339}
340
341#if DBG_MAX_REG_NUM > 0
342void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
343{
344 int i;
345 int idx = 0;
346 char *ptr = (char *)gdb_regs;
347
348 for (i = 0; i < DBG_MAX_REG_NUM; i++) {
349 dbg_get_reg(i, ptr + idx, regs);
350 idx += dbg_reg_def[i].size;
351 }
352}
353
354void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
355{
356 int i;
357 int idx = 0;
358 char *ptr = (char *)gdb_regs;
359
360 for (i = 0; i < DBG_MAX_REG_NUM; i++) {
361 dbg_set_reg(i, ptr + idx, regs);
362 idx += dbg_reg_def[i].size;
363 }
364}
365#endif /* DBG_MAX_REG_NUM > 0 */
366
367/* Write memory due to an 'M' or 'X' packet. */
368static int write_mem_msg(int binary)
369{
370 char *ptr = &remcom_in_buffer[1];
371 unsigned long addr;
372 unsigned long length;
373 int err;
374
375 if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
376 kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
377 if (binary)
378 err = kgdb_ebin2mem(ptr, (char *)addr, length);
379 else
380 err = kgdb_hex2mem(ptr, (char *)addr, length);
381 if (err)
382 return err;
383 if (CACHE_FLUSH_IS_SAFE)
384 flush_icache_range(addr, addr + length);
385 return 0;
386 }
387
388 return -EINVAL;
389}
390
391static void error_packet(char *pkt, int error)
392{
393 error = -error;
394 pkt[0] = 'E';
395 pkt[1] = hex_asc[(error / 10)];
396 pkt[2] = hex_asc[(error % 10)];
397 pkt[3] = '\0';
398}
399
400/*
401 * Thread ID accessors. We represent a flat TID space to GDB, where
402 * the per CPU idle threads (which under Linux all have PID 0) are
403 * remapped to negative TIDs.
404 */
405
406#define BUF_THREAD_ID_SIZE 8
407
408static char *pack_threadid(char *pkt, unsigned char *id)
409{
410 unsigned char *limit;
411 int lzero = 1;
412
413 limit = id + (BUF_THREAD_ID_SIZE / 2);
414 while (id < limit) {
415 if (!lzero || *id != 0) {
416 pkt = hex_byte_pack(pkt, *id);
417 lzero = 0;
418 }
419 id++;
420 }
421
422 if (lzero)
423 pkt = hex_byte_pack(pkt, 0);
424
425 return pkt;
426}
427
428static void int_to_threadref(unsigned char *id, int value)
429{
430 put_unaligned_be32(value, id);
431}
432
433static struct task_struct *getthread(struct pt_regs *regs, int tid)
434{
435 /*
436 * Non-positive TIDs are remapped to the cpu shadow information
437 */
438 if (tid == 0 || tid == -1)
439 tid = -atomic_read(&kgdb_active) - 2;
440 if (tid < -1 && tid > -NR_CPUS - 2) {
441 if (kgdb_info[-tid - 2].task)
442 return kgdb_info[-tid - 2].task;
443 else
444 return idle_task(-tid - 2);
445 }
446 if (tid <= 0) {
447 printk(KERN_ERR "KGDB: Internal thread select error\n");
448 dump_stack();
449 return NULL;
450 }
451
452 /*
453 * find_task_by_pid_ns() does not take the tasklist lock anymore
454 * but is nicely RCU locked - hence is a pretty resilient
455 * thing to use:
456 */
457 return find_task_by_pid_ns(tid, &init_pid_ns);
458}
459
460
461/*
462 * Remap normal tasks to their real PID,
463 * CPU shadow threads are mapped to -CPU - 2
464 */
465static inline int shadow_pid(int realpid)
466{
467 if (realpid)
468 return realpid;
469
470 return -raw_smp_processor_id() - 2;
471}
472
473/*
474 * All the functions that start with gdb_cmd are the various
475 * operations to implement the handlers for the gdbserial protocol
476 * where KGDB is communicating with an external debugger
477 */
478
479/* Handle the '?' status packets */
480static void gdb_cmd_status(struct kgdb_state *ks)
481{
482 /*
483 * We know that this packet is only sent
484 * during initial connect. So to be safe,
485 * we clear out our breakpoints now in case
486 * GDB is reconnecting.
487 */
488 dbg_remove_all_break();
489
490 remcom_out_buffer[0] = 'S';
491 hex_byte_pack(&remcom_out_buffer[1], ks->signo);
492}
493
494static void gdb_get_regs_helper(struct kgdb_state *ks)
495{
496 struct task_struct *thread;
497 void *local_debuggerinfo;
498 int i;
499
500 thread = kgdb_usethread;
501 if (!thread) {
502 thread = kgdb_info[ks->cpu].task;
503 local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
504 } else {
505 local_debuggerinfo = NULL;
506 for_each_online_cpu(i) {
507 /*
508 * Try to find the task on some other
509 * or possibly this node if we do not
510 * find the matching task then we try
511 * to approximate the results.
512 */
513 if (thread == kgdb_info[i].task)
514 local_debuggerinfo = kgdb_info[i].debuggerinfo;
515 }
516 }
517
518 /*
519 * All threads that don't have debuggerinfo should be
520 * in schedule() sleeping, since all other CPUs
521 * are in kgdb_wait, and thus have debuggerinfo.
522 */
523 if (local_debuggerinfo) {
524 pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
525 } else {
526 /*
527 * Pull stuff saved during switch_to; nothing
528 * else is accessible (or even particularly
529 * relevant).
530 *
531 * This should be enough for a stack trace.
532 */
533 sleeping_thread_to_gdb_regs(gdb_regs, thread);
534 }
535}
536
537/* Handle the 'g' get registers request */
538static void gdb_cmd_getregs(struct kgdb_state *ks)
539{
540 gdb_get_regs_helper(ks);
541 kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
542}
543
544/* Handle the 'G' set registers request */
545static void gdb_cmd_setregs(struct kgdb_state *ks)
546{
547 kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
548
549 if (kgdb_usethread && kgdb_usethread != current) {
550 error_packet(remcom_out_buffer, -EINVAL);
551 } else {
552 gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
553 strcpy(remcom_out_buffer, "OK");
554 }
555}
556
557/* Handle the 'm' memory read bytes */
558static void gdb_cmd_memread(struct kgdb_state *ks)
559{
560 char *ptr = &remcom_in_buffer[1];
561 unsigned long length;
562 unsigned long addr;
563 char *err;
564
565 if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
566 kgdb_hex2long(&ptr, &length) > 0) {
567 err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
568 if (!err)
569 error_packet(remcom_out_buffer, -EINVAL);
570 } else {
571 error_packet(remcom_out_buffer, -EINVAL);
572 }
573}
574
575/* Handle the 'M' memory write bytes */
576static void gdb_cmd_memwrite(struct kgdb_state *ks)
577{
578 int err = write_mem_msg(0);
579
580 if (err)
581 error_packet(remcom_out_buffer, err);
582 else
583 strcpy(remcom_out_buffer, "OK");
584}
585
586#if DBG_MAX_REG_NUM > 0
587static char *gdb_hex_reg_helper(int regnum, char *out)
588{
589 int i;
590 int offset = 0;
591
592 for (i = 0; i < regnum; i++)
593 offset += dbg_reg_def[i].size;
594 return kgdb_mem2hex((char *)gdb_regs + offset, out,
595 dbg_reg_def[i].size);
596}
597
598/* Handle the 'p' individual regster get */
599static void gdb_cmd_reg_get(struct kgdb_state *ks)
600{
601 unsigned long regnum;
602 char *ptr = &remcom_in_buffer[1];
603
604 kgdb_hex2long(&ptr, ®num);
605 if (regnum >= DBG_MAX_REG_NUM) {
606 error_packet(remcom_out_buffer, -EINVAL);
607 return;
608 }
609 gdb_get_regs_helper(ks);
610 gdb_hex_reg_helper(regnum, remcom_out_buffer);
611}
612
613/* Handle the 'P' individual regster set */
614static void gdb_cmd_reg_set(struct kgdb_state *ks)
615{
616 unsigned long regnum;
617 char *ptr = &remcom_in_buffer[1];
618 int i = 0;
619
620 kgdb_hex2long(&ptr, ®num);
621 if (*ptr++ != '=' ||
622 !(!kgdb_usethread || kgdb_usethread == current) ||
623 !dbg_get_reg(regnum, gdb_regs, ks->linux_regs)) {
624 error_packet(remcom_out_buffer, -EINVAL);
625 return;
626 }
627 memset(gdb_regs, 0, sizeof(gdb_regs));
628 while (i < sizeof(gdb_regs) * 2)
629 if (hex_to_bin(ptr[i]) >= 0)
630 i++;
631 else
632 break;
633 i = i / 2;
634 kgdb_hex2mem(ptr, (char *)gdb_regs, i);
635 dbg_set_reg(regnum, gdb_regs, ks->linux_regs);
636 strcpy(remcom_out_buffer, "OK");
637}
638#endif /* DBG_MAX_REG_NUM > 0 */
639
640/* Handle the 'X' memory binary write bytes */
641static void gdb_cmd_binwrite(struct kgdb_state *ks)
642{
643 int err = write_mem_msg(1);
644
645 if (err)
646 error_packet(remcom_out_buffer, err);
647 else
648 strcpy(remcom_out_buffer, "OK");
649}
650
651/* Handle the 'D' or 'k', detach or kill packets */
652static void gdb_cmd_detachkill(struct kgdb_state *ks)
653{
654 int error;
655
656 /* The detach case */
657 if (remcom_in_buffer[0] == 'D') {
658 error = dbg_remove_all_break();
659 if (error < 0) {
660 error_packet(remcom_out_buffer, error);
661 } else {
662 strcpy(remcom_out_buffer, "OK");
663 kgdb_connected = 0;
664 }
665 put_packet(remcom_out_buffer);
666 } else {
667 /*
668 * Assume the kill case, with no exit code checking,
669 * trying to force detach the debugger:
670 */
671 dbg_remove_all_break();
672 kgdb_connected = 0;
673 }
674}
675
676/* Handle the 'R' reboot packets */
677static int gdb_cmd_reboot(struct kgdb_state *ks)
678{
679 /* For now, only honor R0 */
680 if (strcmp(remcom_in_buffer, "R0") == 0) {
681 printk(KERN_CRIT "Executing emergency reboot\n");
682 strcpy(remcom_out_buffer, "OK");
683 put_packet(remcom_out_buffer);
684
685 /*
686 * Execution should not return from
687 * machine_emergency_restart()
688 */
689 machine_emergency_restart();
690 kgdb_connected = 0;
691
692 return 1;
693 }
694 return 0;
695}
696
697/* Handle the 'q' query packets */
698static void gdb_cmd_query(struct kgdb_state *ks)
699{
700 struct task_struct *g;
701 struct task_struct *p;
702 unsigned char thref[BUF_THREAD_ID_SIZE];
703 char *ptr;
704 int i;
705 int cpu;
706 int finished = 0;
707
708 switch (remcom_in_buffer[1]) {
709 case 's':
710 case 'f':
711 if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10))
712 break;
713
714 i = 0;
715 remcom_out_buffer[0] = 'm';
716 ptr = remcom_out_buffer + 1;
717 if (remcom_in_buffer[1] == 'f') {
718 /* Each cpu is a shadow thread */
719 for_each_online_cpu(cpu) {
720 ks->thr_query = 0;
721 int_to_threadref(thref, -cpu - 2);
722 ptr = pack_threadid(ptr, thref);
723 *(ptr++) = ',';
724 i++;
725 }
726 }
727
728 do_each_thread(g, p) {
729 if (i >= ks->thr_query && !finished) {
730 int_to_threadref(thref, p->pid);
731 ptr = pack_threadid(ptr, thref);
732 *(ptr++) = ',';
733 ks->thr_query++;
734 if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0)
735 finished = 1;
736 }
737 i++;
738 } while_each_thread(g, p);
739
740 *(--ptr) = '\0';
741 break;
742
743 case 'C':
744 /* Current thread id */
745 strcpy(remcom_out_buffer, "QC");
746 ks->threadid = shadow_pid(current->pid);
747 int_to_threadref(thref, ks->threadid);
748 pack_threadid(remcom_out_buffer + 2, thref);
749 break;
750 case 'T':
751 if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16))
752 break;
753
754 ks->threadid = 0;
755 ptr = remcom_in_buffer + 17;
756 kgdb_hex2long(&ptr, &ks->threadid);
757 if (!getthread(ks->linux_regs, ks->threadid)) {
758 error_packet(remcom_out_buffer, -EINVAL);
759 break;
760 }
761 if ((int)ks->threadid > 0) {
762 kgdb_mem2hex(getthread(ks->linux_regs,
763 ks->threadid)->comm,
764 remcom_out_buffer, 16);
765 } else {
766 static char tmpstr[23 + BUF_THREAD_ID_SIZE];
767
768 sprintf(tmpstr, "shadowCPU%d",
769 (int)(-ks->threadid - 2));
770 kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
771 }
772 break;
773#ifdef CONFIG_KGDB_KDB
774 case 'R':
775 if (strncmp(remcom_in_buffer, "qRcmd,", 6) == 0) {
776 int len = strlen(remcom_in_buffer + 6);
777
778 if ((len % 2) != 0) {
779 strcpy(remcom_out_buffer, "E01");
780 break;
781 }
782 kgdb_hex2mem(remcom_in_buffer + 6,
783 remcom_out_buffer, len);
784 len = len / 2;
785 remcom_out_buffer[len++] = 0;
786
787 kdb_common_init_state(ks);
788 kdb_parse(remcom_out_buffer);
789 kdb_common_deinit_state();
790
791 strcpy(remcom_out_buffer, "OK");
792 }
793 break;
794#endif
795 }
796}
797
798/* Handle the 'H' task query packets */
799static void gdb_cmd_task(struct kgdb_state *ks)
800{
801 struct task_struct *thread;
802 char *ptr;
803
804 switch (remcom_in_buffer[1]) {
805 case 'g':
806 ptr = &remcom_in_buffer[2];
807 kgdb_hex2long(&ptr, &ks->threadid);
808 thread = getthread(ks->linux_regs, ks->threadid);
809 if (!thread && ks->threadid > 0) {
810 error_packet(remcom_out_buffer, -EINVAL);
811 break;
812 }
813 kgdb_usethread = thread;
814 ks->kgdb_usethreadid = ks->threadid;
815 strcpy(remcom_out_buffer, "OK");
816 break;
817 case 'c':
818 ptr = &remcom_in_buffer[2];
819 kgdb_hex2long(&ptr, &ks->threadid);
820 if (!ks->threadid) {
821 kgdb_contthread = NULL;
822 } else {
823 thread = getthread(ks->linux_regs, ks->threadid);
824 if (!thread && ks->threadid > 0) {
825 error_packet(remcom_out_buffer, -EINVAL);
826 break;
827 }
828 kgdb_contthread = thread;
829 }
830 strcpy(remcom_out_buffer, "OK");
831 break;
832 }
833}
834
835/* Handle the 'T' thread query packets */
836static void gdb_cmd_thread(struct kgdb_state *ks)
837{
838 char *ptr = &remcom_in_buffer[1];
839 struct task_struct *thread;
840
841 kgdb_hex2long(&ptr, &ks->threadid);
842 thread = getthread(ks->linux_regs, ks->threadid);
843 if (thread)
844 strcpy(remcom_out_buffer, "OK");
845 else
846 error_packet(remcom_out_buffer, -EINVAL);
847}
848
849/* Handle the 'z' or 'Z' breakpoint remove or set packets */
850static void gdb_cmd_break(struct kgdb_state *ks)
851{
852 /*
853 * Since GDB-5.3, it's been drafted that '0' is a software
854 * breakpoint, '1' is a hardware breakpoint, so let's do that.
855 */
856 char *bpt_type = &remcom_in_buffer[1];
857 char *ptr = &remcom_in_buffer[2];
858 unsigned long addr;
859 unsigned long length;
860 int error = 0;
861
862 if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
863 /* Unsupported */
864 if (*bpt_type > '4')
865 return;
866 } else {
867 if (*bpt_type != '0' && *bpt_type != '1')
868 /* Unsupported. */
869 return;
870 }
871
872 /*
873 * Test if this is a hardware breakpoint, and
874 * if we support it:
875 */
876 if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
877 /* Unsupported. */
878 return;
879
880 if (*(ptr++) != ',') {
881 error_packet(remcom_out_buffer, -EINVAL);
882 return;
883 }
884 if (!kgdb_hex2long(&ptr, &addr)) {
885 error_packet(remcom_out_buffer, -EINVAL);
886 return;
887 }
888 if (*(ptr++) != ',' ||
889 !kgdb_hex2long(&ptr, &length)) {
890 error_packet(remcom_out_buffer, -EINVAL);
891 return;
892 }
893
894 if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
895 error = dbg_set_sw_break(addr);
896 else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
897 error = dbg_remove_sw_break(addr);
898 else if (remcom_in_buffer[0] == 'Z')
899 error = arch_kgdb_ops.set_hw_breakpoint(addr,
900 (int)length, *bpt_type - '0');
901 else if (remcom_in_buffer[0] == 'z')
902 error = arch_kgdb_ops.remove_hw_breakpoint(addr,
903 (int) length, *bpt_type - '0');
904
905 if (error == 0)
906 strcpy(remcom_out_buffer, "OK");
907 else
908 error_packet(remcom_out_buffer, error);
909}
910
911/* Handle the 'C' signal / exception passing packets */
912static int gdb_cmd_exception_pass(struct kgdb_state *ks)
913{
914 /* C09 == pass exception
915 * C15 == detach kgdb, pass exception
916 */
917 if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
918
919 ks->pass_exception = 1;
920 remcom_in_buffer[0] = 'c';
921
922 } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
923
924 ks->pass_exception = 1;
925 remcom_in_buffer[0] = 'D';
926 dbg_remove_all_break();
927 kgdb_connected = 0;
928 return 1;
929
930 } else {
931 gdbstub_msg_write("KGDB only knows signal 9 (pass)"
932 " and 15 (pass and disconnect)\n"
933 "Executing a continue without signal passing\n", 0);
934 remcom_in_buffer[0] = 'c';
935 }
936
937 /* Indicate fall through */
938 return -1;
939}
940
941/*
942 * This function performs all gdbserial command procesing
943 */
944int gdb_serial_stub(struct kgdb_state *ks)
945{
946 int error = 0;
947 int tmp;
948
949 /* Initialize comm buffer and globals. */
950 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
951 kgdb_usethread = kgdb_info[ks->cpu].task;
952 ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
953 ks->pass_exception = 0;
954
955 if (kgdb_connected) {
956 unsigned char thref[BUF_THREAD_ID_SIZE];
957 char *ptr;
958
959 /* Reply to host that an exception has occurred */
960 ptr = remcom_out_buffer;
961 *ptr++ = 'T';
962 ptr = hex_byte_pack(ptr, ks->signo);
963 ptr += strlen(strcpy(ptr, "thread:"));
964 int_to_threadref(thref, shadow_pid(current->pid));
965 ptr = pack_threadid(ptr, thref);
966 *ptr++ = ';';
967 put_packet(remcom_out_buffer);
968 }
969
970 while (1) {
971 error = 0;
972
973 /* Clear the out buffer. */
974 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
975
976 get_packet(remcom_in_buffer);
977
978 switch (remcom_in_buffer[0]) {
979 case '?': /* gdbserial status */
980 gdb_cmd_status(ks);
981 break;
982 case 'g': /* return the value of the CPU registers */
983 gdb_cmd_getregs(ks);
984 break;
985 case 'G': /* set the value of the CPU registers - return OK */
986 gdb_cmd_setregs(ks);
987 break;
988 case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */
989 gdb_cmd_memread(ks);
990 break;
991 case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
992 gdb_cmd_memwrite(ks);
993 break;
994#if DBG_MAX_REG_NUM > 0
995 case 'p': /* pXX Return gdb register XX (in hex) */
996 gdb_cmd_reg_get(ks);
997 break;
998 case 'P': /* PXX=aaaa Set gdb register XX to aaaa (in hex) */
999 gdb_cmd_reg_set(ks);
1000 break;
1001#endif /* DBG_MAX_REG_NUM > 0 */
1002 case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
1003 gdb_cmd_binwrite(ks);
1004 break;
1005 /* kill or detach. KGDB should treat this like a
1006 * continue.
1007 */
1008 case 'D': /* Debugger detach */
1009 case 'k': /* Debugger detach via kill */
1010 gdb_cmd_detachkill(ks);
1011 goto default_handle;
1012 case 'R': /* Reboot */
1013 if (gdb_cmd_reboot(ks))
1014 goto default_handle;
1015 break;
1016 case 'q': /* query command */
1017 gdb_cmd_query(ks);
1018 break;
1019 case 'H': /* task related */
1020 gdb_cmd_task(ks);
1021 break;
1022 case 'T': /* Query thread status */
1023 gdb_cmd_thread(ks);
1024 break;
1025 case 'z': /* Break point remove */
1026 case 'Z': /* Break point set */
1027 gdb_cmd_break(ks);
1028 break;
1029#ifdef CONFIG_KGDB_KDB
1030 case '3': /* Escape into back into kdb */
1031 if (remcom_in_buffer[1] == '\0') {
1032 gdb_cmd_detachkill(ks);
1033 return DBG_PASS_EVENT;
1034 }
1035#endif
1036 /* Fall through */
1037 case 'C': /* Exception passing */
1038 tmp = gdb_cmd_exception_pass(ks);
1039 if (tmp > 0)
1040 goto default_handle;
1041 if (tmp == 0)
1042 break;
1043 /* Fall through - on tmp < 0 */
1044 case 'c': /* Continue packet */
1045 case 's': /* Single step packet */
1046 if (kgdb_contthread && kgdb_contthread != current) {
1047 /* Can't switch threads in kgdb */
1048 error_packet(remcom_out_buffer, -EINVAL);
1049 break;
1050 }
1051 dbg_activate_sw_breakpoints();
1052 /* Fall through - to default processing */
1053 default:
1054default_handle:
1055 error = kgdb_arch_handle_exception(ks->ex_vector,
1056 ks->signo,
1057 ks->err_code,
1058 remcom_in_buffer,
1059 remcom_out_buffer,
1060 ks->linux_regs);
1061 /*
1062 * Leave cmd processing on error, detach,
1063 * kill, continue, or single step.
1064 */
1065 if (error >= 0 || remcom_in_buffer[0] == 'D' ||
1066 remcom_in_buffer[0] == 'k') {
1067 error = 0;
1068 goto kgdb_exit;
1069 }
1070
1071 }
1072
1073 /* reply to the request */
1074 put_packet(remcom_out_buffer);
1075 }
1076
1077kgdb_exit:
1078 if (ks->pass_exception)
1079 error = 1;
1080 return error;
1081}
1082
1083int gdbstub_state(struct kgdb_state *ks, char *cmd)
1084{
1085 int error;
1086
1087 switch (cmd[0]) {
1088 case 'e':
1089 error = kgdb_arch_handle_exception(ks->ex_vector,
1090 ks->signo,
1091 ks->err_code,
1092 remcom_in_buffer,
1093 remcom_out_buffer,
1094 ks->linux_regs);
1095 return error;
1096 case 's':
1097 case 'c':
1098 strscpy(remcom_in_buffer, cmd, sizeof(remcom_in_buffer));
1099 return 0;
1100 case '$':
1101 strscpy(remcom_in_buffer, cmd, sizeof(remcom_in_buffer));
1102 gdbstub_use_prev_in_buf = strlen(remcom_in_buffer);
1103 gdbstub_prev_in_buf_pos = 0;
1104 return 0;
1105 }
1106 dbg_io_ops->write_char('+');
1107 put_packet(remcom_out_buffer);
1108 return 0;
1109}
1110
1111/**
1112 * gdbstub_exit - Send an exit message to GDB
1113 * @status: The exit code to report.
1114 */
1115void gdbstub_exit(int status)
1116{
1117 unsigned char checksum, ch, buffer[3];
1118 int loop;
1119
1120 if (!kgdb_connected)
1121 return;
1122 kgdb_connected = 0;
1123
1124 if (!dbg_io_ops || dbg_kdb_mode)
1125 return;
1126
1127 buffer[0] = 'W';
1128 buffer[1] = hex_asc_hi(status);
1129 buffer[2] = hex_asc_lo(status);
1130
1131 dbg_io_ops->write_char('$');
1132 checksum = 0;
1133
1134 for (loop = 0; loop < 3; loop++) {
1135 ch = buffer[loop];
1136 checksum += ch;
1137 dbg_io_ops->write_char(ch);
1138 }
1139
1140 dbg_io_ops->write_char('#');
1141 dbg_io_ops->write_char(hex_asc_hi(checksum));
1142 dbg_io_ops->write_char(hex_asc_lo(checksum));
1143
1144 /* make sure the output is flushed, lest the bootloader clobber it */
1145 if (dbg_io_ops->flush)
1146 dbg_io_ops->flush();
1147}
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Kernel Debug Core
4 *
5 * Maintainer: Jason Wessel <jason.wessel@windriver.com>
6 *
7 * Copyright (C) 2000-2001 VERITAS Software Corporation.
8 * Copyright (C) 2002-2004 Timesys Corporation
9 * Copyright (C) 2003-2004 Amit S. Kale <amitkale@linsyssoft.com>
10 * Copyright (C) 2004 Pavel Machek <pavel@ucw.cz>
11 * Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org>
12 * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd.
13 * Copyright (C) 2005-2009 Wind River Systems, Inc.
14 * Copyright (C) 2007 MontaVista Software, Inc.
15 * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
16 *
17 * Contributors at various stages not listed above:
18 * Jason Wessel ( jason.wessel@windriver.com )
19 * George Anzinger <george@mvista.com>
20 * Anurekh Saxena (anurekh.saxena@timesys.com)
21 * Lake Stevens Instrument Division (Glenn Engel)
22 * Jim Kingdon, Cygnus Support.
23 *
24 * Original KGDB stub: David Grothe <dave@gcom.com>,
25 * Tigran Aivazian <tigran@sco.com>
26 */
27
28#include <linux/kernel.h>
29#include <linux/sched/signal.h>
30#include <linux/kgdb.h>
31#include <linux/kdb.h>
32#include <linux/serial_core.h>
33#include <linux/reboot.h>
34#include <linux/uaccess.h>
35#include <asm/cacheflush.h>
36#include <asm/unaligned.h>
37#include "debug_core.h"
38
39#define KGDB_MAX_THREAD_QUERY 17
40
41/* Our I/O buffers. */
42static char remcom_in_buffer[BUFMAX];
43static char remcom_out_buffer[BUFMAX];
44static int gdbstub_use_prev_in_buf;
45static int gdbstub_prev_in_buf_pos;
46
47/* Storage for the registers, in GDB format. */
48static unsigned long gdb_regs[(NUMREGBYTES +
49 sizeof(unsigned long) - 1) /
50 sizeof(unsigned long)];
51
52/*
53 * GDB remote protocol parser:
54 */
55
56#ifdef CONFIG_KGDB_KDB
57static int gdbstub_read_wait(void)
58{
59 int ret = -1;
60 int i;
61
62 if (unlikely(gdbstub_use_prev_in_buf)) {
63 if (gdbstub_prev_in_buf_pos < gdbstub_use_prev_in_buf)
64 return remcom_in_buffer[gdbstub_prev_in_buf_pos++];
65 else
66 gdbstub_use_prev_in_buf = 0;
67 }
68
69 /* poll any additional I/O interfaces that are defined */
70 while (ret < 0)
71 for (i = 0; kdb_poll_funcs[i] != NULL; i++) {
72 ret = kdb_poll_funcs[i]();
73 if (ret > 0)
74 break;
75 }
76 return ret;
77}
78#else
79static int gdbstub_read_wait(void)
80{
81 int ret = dbg_io_ops->read_char();
82 while (ret == NO_POLL_CHAR)
83 ret = dbg_io_ops->read_char();
84 return ret;
85}
86#endif
87/* scan for the sequence $<data>#<checksum> */
88static void get_packet(char *buffer)
89{
90 unsigned char checksum;
91 unsigned char xmitcsum;
92 int count;
93 char ch;
94
95 do {
96 /*
97 * Spin and wait around for the start character, ignore all
98 * other characters:
99 */
100 while ((ch = (gdbstub_read_wait())) != '$')
101 /* nothing */;
102
103 kgdb_connected = 1;
104 checksum = 0;
105 xmitcsum = -1;
106
107 count = 0;
108
109 /*
110 * now, read until a # or end of buffer is found:
111 */
112 while (count < (BUFMAX - 1)) {
113 ch = gdbstub_read_wait();
114 if (ch == '#')
115 break;
116 checksum = checksum + ch;
117 buffer[count] = ch;
118 count = count + 1;
119 }
120
121 if (ch == '#') {
122 xmitcsum = hex_to_bin(gdbstub_read_wait()) << 4;
123 xmitcsum += hex_to_bin(gdbstub_read_wait());
124
125 if (checksum != xmitcsum)
126 /* failed checksum */
127 dbg_io_ops->write_char('-');
128 else
129 /* successful transfer */
130 dbg_io_ops->write_char('+');
131 if (dbg_io_ops->flush)
132 dbg_io_ops->flush();
133 }
134 buffer[count] = 0;
135 } while (checksum != xmitcsum);
136}
137
138/*
139 * Send the packet in buffer.
140 * Check for gdb connection if asked for.
141 */
142static void put_packet(char *buffer)
143{
144 unsigned char checksum;
145 int count;
146 char ch;
147
148 /*
149 * $<packet info>#<checksum>.
150 */
151 while (1) {
152 dbg_io_ops->write_char('$');
153 checksum = 0;
154 count = 0;
155
156 while ((ch = buffer[count])) {
157 dbg_io_ops->write_char(ch);
158 checksum += ch;
159 count++;
160 }
161
162 dbg_io_ops->write_char('#');
163 dbg_io_ops->write_char(hex_asc_hi(checksum));
164 dbg_io_ops->write_char(hex_asc_lo(checksum));
165 if (dbg_io_ops->flush)
166 dbg_io_ops->flush();
167
168 /* Now see what we get in reply. */
169 ch = gdbstub_read_wait();
170
171 if (ch == 3)
172 ch = gdbstub_read_wait();
173
174 /* If we get an ACK, we are done. */
175 if (ch == '+')
176 return;
177
178 /*
179 * If we get the start of another packet, this means
180 * that GDB is attempting to reconnect. We will NAK
181 * the packet being sent, and stop trying to send this
182 * packet.
183 */
184 if (ch == '$') {
185 dbg_io_ops->write_char('-');
186 if (dbg_io_ops->flush)
187 dbg_io_ops->flush();
188 return;
189 }
190 }
191}
192
193static char gdbmsgbuf[BUFMAX + 1];
194
195void gdbstub_msg_write(const char *s, int len)
196{
197 char *bufptr;
198 int wcount;
199 int i;
200
201 if (len == 0)
202 len = strlen(s);
203
204 /* 'O'utput */
205 gdbmsgbuf[0] = 'O';
206
207 /* Fill and send buffers... */
208 while (len > 0) {
209 bufptr = gdbmsgbuf + 1;
210
211 /* Calculate how many this time */
212 if ((len << 1) > (BUFMAX - 2))
213 wcount = (BUFMAX - 2) >> 1;
214 else
215 wcount = len;
216
217 /* Pack in hex chars */
218 for (i = 0; i < wcount; i++)
219 bufptr = hex_byte_pack(bufptr, s[i]);
220 *bufptr = '\0';
221
222 /* Move up */
223 s += wcount;
224 len -= wcount;
225
226 /* Write packet */
227 put_packet(gdbmsgbuf);
228 }
229}
230
231/*
232 * Convert the memory pointed to by mem into hex, placing result in
233 * buf. Return a pointer to the last char put in buf (null). May
234 * return an error.
235 */
236char *kgdb_mem2hex(char *mem, char *buf, int count)
237{
238 char *tmp;
239 int err;
240
241 /*
242 * We use the upper half of buf as an intermediate buffer for the
243 * raw memory copy. Hex conversion will work against this one.
244 */
245 tmp = buf + count;
246
247 err = copy_from_kernel_nofault(tmp, mem, count);
248 if (err)
249 return NULL;
250 while (count > 0) {
251 buf = hex_byte_pack(buf, *tmp);
252 tmp++;
253 count--;
254 }
255 *buf = 0;
256
257 return buf;
258}
259
260/*
261 * Convert the hex array pointed to by buf into binary to be placed in
262 * mem. Return a pointer to the character AFTER the last byte
263 * written. May return an error.
264 */
265int kgdb_hex2mem(char *buf, char *mem, int count)
266{
267 char *tmp_raw;
268 char *tmp_hex;
269
270 /*
271 * We use the upper half of buf as an intermediate buffer for the
272 * raw memory that is converted from hex.
273 */
274 tmp_raw = buf + count * 2;
275
276 tmp_hex = tmp_raw - 1;
277 while (tmp_hex >= buf) {
278 tmp_raw--;
279 *tmp_raw = hex_to_bin(*tmp_hex--);
280 *tmp_raw |= hex_to_bin(*tmp_hex--) << 4;
281 }
282
283 return copy_to_kernel_nofault(mem, tmp_raw, count);
284}
285
286/*
287 * While we find nice hex chars, build a long_val.
288 * Return number of chars processed.
289 */
290int kgdb_hex2long(char **ptr, unsigned long *long_val)
291{
292 int hex_val;
293 int num = 0;
294 int negate = 0;
295
296 *long_val = 0;
297
298 if (**ptr == '-') {
299 negate = 1;
300 (*ptr)++;
301 }
302 while (**ptr) {
303 hex_val = hex_to_bin(**ptr);
304 if (hex_val < 0)
305 break;
306
307 *long_val = (*long_val << 4) | hex_val;
308 num++;
309 (*ptr)++;
310 }
311
312 if (negate)
313 *long_val = -*long_val;
314
315 return num;
316}
317
318/*
319 * Copy the binary array pointed to by buf into mem. Fix $, #, and
320 * 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success.
321 * The input buf is overwritten with the result to write to mem.
322 */
323static int kgdb_ebin2mem(char *buf, char *mem, int count)
324{
325 int size = 0;
326 char *c = buf;
327
328 while (count-- > 0) {
329 c[size] = *buf++;
330 if (c[size] == 0x7d)
331 c[size] = *buf++ ^ 0x20;
332 size++;
333 }
334
335 return copy_to_kernel_nofault(mem, c, size);
336}
337
338#if DBG_MAX_REG_NUM > 0
339void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
340{
341 int i;
342 int idx = 0;
343 char *ptr = (char *)gdb_regs;
344
345 for (i = 0; i < DBG_MAX_REG_NUM; i++) {
346 dbg_get_reg(i, ptr + idx, regs);
347 idx += dbg_reg_def[i].size;
348 }
349}
350
351void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
352{
353 int i;
354 int idx = 0;
355 char *ptr = (char *)gdb_regs;
356
357 for (i = 0; i < DBG_MAX_REG_NUM; i++) {
358 dbg_set_reg(i, ptr + idx, regs);
359 idx += dbg_reg_def[i].size;
360 }
361}
362#endif /* DBG_MAX_REG_NUM > 0 */
363
364/* Write memory due to an 'M' or 'X' packet. */
365static int write_mem_msg(int binary)
366{
367 char *ptr = &remcom_in_buffer[1];
368 unsigned long addr;
369 unsigned long length;
370 int err;
371
372 if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' &&
373 kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') {
374 if (binary)
375 err = kgdb_ebin2mem(ptr, (char *)addr, length);
376 else
377 err = kgdb_hex2mem(ptr, (char *)addr, length);
378 if (err)
379 return err;
380 if (CACHE_FLUSH_IS_SAFE)
381 flush_icache_range(addr, addr + length);
382 return 0;
383 }
384
385 return -EINVAL;
386}
387
388static void error_packet(char *pkt, int error)
389{
390 error = -error;
391 pkt[0] = 'E';
392 pkt[1] = hex_asc[(error / 10)];
393 pkt[2] = hex_asc[(error % 10)];
394 pkt[3] = '\0';
395}
396
397/*
398 * Thread ID accessors. We represent a flat TID space to GDB, where
399 * the per CPU idle threads (which under Linux all have PID 0) are
400 * remapped to negative TIDs.
401 */
402
403#define BUF_THREAD_ID_SIZE 8
404
405static char *pack_threadid(char *pkt, unsigned char *id)
406{
407 unsigned char *limit;
408 int lzero = 1;
409
410 limit = id + (BUF_THREAD_ID_SIZE / 2);
411 while (id < limit) {
412 if (!lzero || *id != 0) {
413 pkt = hex_byte_pack(pkt, *id);
414 lzero = 0;
415 }
416 id++;
417 }
418
419 if (lzero)
420 pkt = hex_byte_pack(pkt, 0);
421
422 return pkt;
423}
424
425static void int_to_threadref(unsigned char *id, int value)
426{
427 put_unaligned_be32(value, id);
428}
429
430static struct task_struct *getthread(struct pt_regs *regs, int tid)
431{
432 /*
433 * Non-positive TIDs are remapped to the cpu shadow information
434 */
435 if (tid == 0 || tid == -1)
436 tid = -atomic_read(&kgdb_active) - 2;
437 if (tid < -1 && tid > -NR_CPUS - 2) {
438 if (kgdb_info[-tid - 2].task)
439 return kgdb_info[-tid - 2].task;
440 else
441 return idle_task(-tid - 2);
442 }
443 if (tid <= 0) {
444 printk(KERN_ERR "KGDB: Internal thread select error\n");
445 dump_stack();
446 return NULL;
447 }
448
449 /*
450 * find_task_by_pid_ns() does not take the tasklist lock anymore
451 * but is nicely RCU locked - hence is a pretty resilient
452 * thing to use:
453 */
454 return find_task_by_pid_ns(tid, &init_pid_ns);
455}
456
457
458/*
459 * Remap normal tasks to their real PID,
460 * CPU shadow threads are mapped to -CPU - 2
461 */
462static inline int shadow_pid(int realpid)
463{
464 if (realpid)
465 return realpid;
466
467 return -raw_smp_processor_id() - 2;
468}
469
470/*
471 * All the functions that start with gdb_cmd are the various
472 * operations to implement the handlers for the gdbserial protocol
473 * where KGDB is communicating with an external debugger
474 */
475
476/* Handle the '?' status packets */
477static void gdb_cmd_status(struct kgdb_state *ks)
478{
479 /*
480 * We know that this packet is only sent
481 * during initial connect. So to be safe,
482 * we clear out our breakpoints now in case
483 * GDB is reconnecting.
484 */
485 dbg_remove_all_break();
486
487 remcom_out_buffer[0] = 'S';
488 hex_byte_pack(&remcom_out_buffer[1], ks->signo);
489}
490
491static void gdb_get_regs_helper(struct kgdb_state *ks)
492{
493 struct task_struct *thread;
494 void *local_debuggerinfo;
495 int i;
496
497 thread = kgdb_usethread;
498 if (!thread) {
499 thread = kgdb_info[ks->cpu].task;
500 local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo;
501 } else {
502 local_debuggerinfo = NULL;
503 for_each_online_cpu(i) {
504 /*
505 * Try to find the task on some other
506 * or possibly this node if we do not
507 * find the matching task then we try
508 * to approximate the results.
509 */
510 if (thread == kgdb_info[i].task)
511 local_debuggerinfo = kgdb_info[i].debuggerinfo;
512 }
513 }
514
515 /*
516 * All threads that don't have debuggerinfo should be
517 * in schedule() sleeping, since all other CPUs
518 * are in kgdb_wait, and thus have debuggerinfo.
519 */
520 if (local_debuggerinfo) {
521 pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo);
522 } else {
523 /*
524 * Pull stuff saved during switch_to; nothing
525 * else is accessible (or even particularly
526 * relevant).
527 *
528 * This should be enough for a stack trace.
529 */
530 sleeping_thread_to_gdb_regs(gdb_regs, thread);
531 }
532}
533
534/* Handle the 'g' get registers request */
535static void gdb_cmd_getregs(struct kgdb_state *ks)
536{
537 gdb_get_regs_helper(ks);
538 kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES);
539}
540
541/* Handle the 'G' set registers request */
542static void gdb_cmd_setregs(struct kgdb_state *ks)
543{
544 kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES);
545
546 if (kgdb_usethread && kgdb_usethread != current) {
547 error_packet(remcom_out_buffer, -EINVAL);
548 } else {
549 gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs);
550 strcpy(remcom_out_buffer, "OK");
551 }
552}
553
554/* Handle the 'm' memory read bytes */
555static void gdb_cmd_memread(struct kgdb_state *ks)
556{
557 char *ptr = &remcom_in_buffer[1];
558 unsigned long length;
559 unsigned long addr;
560 char *err;
561
562 if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' &&
563 kgdb_hex2long(&ptr, &length) > 0) {
564 err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length);
565 if (!err)
566 error_packet(remcom_out_buffer, -EINVAL);
567 } else {
568 error_packet(remcom_out_buffer, -EINVAL);
569 }
570}
571
572/* Handle the 'M' memory write bytes */
573static void gdb_cmd_memwrite(struct kgdb_state *ks)
574{
575 int err = write_mem_msg(0);
576
577 if (err)
578 error_packet(remcom_out_buffer, err);
579 else
580 strcpy(remcom_out_buffer, "OK");
581}
582
583#if DBG_MAX_REG_NUM > 0
584static char *gdb_hex_reg_helper(int regnum, char *out)
585{
586 int i;
587 int offset = 0;
588
589 for (i = 0; i < regnum; i++)
590 offset += dbg_reg_def[i].size;
591 return kgdb_mem2hex((char *)gdb_regs + offset, out,
592 dbg_reg_def[i].size);
593}
594
595/* Handle the 'p' individual register get */
596static void gdb_cmd_reg_get(struct kgdb_state *ks)
597{
598 unsigned long regnum;
599 char *ptr = &remcom_in_buffer[1];
600
601 kgdb_hex2long(&ptr, ®num);
602 if (regnum >= DBG_MAX_REG_NUM) {
603 error_packet(remcom_out_buffer, -EINVAL);
604 return;
605 }
606 gdb_get_regs_helper(ks);
607 gdb_hex_reg_helper(regnum, remcom_out_buffer);
608}
609
610/* Handle the 'P' individual register set */
611static void gdb_cmd_reg_set(struct kgdb_state *ks)
612{
613 unsigned long regnum;
614 char *ptr = &remcom_in_buffer[1];
615 int i = 0;
616
617 kgdb_hex2long(&ptr, ®num);
618 if (*ptr++ != '=' ||
619 !(!kgdb_usethread || kgdb_usethread == current) ||
620 !dbg_get_reg(regnum, gdb_regs, ks->linux_regs)) {
621 error_packet(remcom_out_buffer, -EINVAL);
622 return;
623 }
624 memset(gdb_regs, 0, sizeof(gdb_regs));
625 while (i < sizeof(gdb_regs) * 2)
626 if (hex_to_bin(ptr[i]) >= 0)
627 i++;
628 else
629 break;
630 i = i / 2;
631 kgdb_hex2mem(ptr, (char *)gdb_regs, i);
632 dbg_set_reg(regnum, gdb_regs, ks->linux_regs);
633 strcpy(remcom_out_buffer, "OK");
634}
635#endif /* DBG_MAX_REG_NUM > 0 */
636
637/* Handle the 'X' memory binary write bytes */
638static void gdb_cmd_binwrite(struct kgdb_state *ks)
639{
640 int err = write_mem_msg(1);
641
642 if (err)
643 error_packet(remcom_out_buffer, err);
644 else
645 strcpy(remcom_out_buffer, "OK");
646}
647
648/* Handle the 'D' or 'k', detach or kill packets */
649static void gdb_cmd_detachkill(struct kgdb_state *ks)
650{
651 int error;
652
653 /* The detach case */
654 if (remcom_in_buffer[0] == 'D') {
655 error = dbg_remove_all_break();
656 if (error < 0) {
657 error_packet(remcom_out_buffer, error);
658 } else {
659 strcpy(remcom_out_buffer, "OK");
660 kgdb_connected = 0;
661 }
662 put_packet(remcom_out_buffer);
663 } else {
664 /*
665 * Assume the kill case, with no exit code checking,
666 * trying to force detach the debugger:
667 */
668 dbg_remove_all_break();
669 kgdb_connected = 0;
670 }
671}
672
673/* Handle the 'R' reboot packets */
674static int gdb_cmd_reboot(struct kgdb_state *ks)
675{
676 /* For now, only honor R0 */
677 if (strcmp(remcom_in_buffer, "R0") == 0) {
678 printk(KERN_CRIT "Executing emergency reboot\n");
679 strcpy(remcom_out_buffer, "OK");
680 put_packet(remcom_out_buffer);
681
682 /*
683 * Execution should not return from
684 * machine_emergency_restart()
685 */
686 machine_emergency_restart();
687 kgdb_connected = 0;
688
689 return 1;
690 }
691 return 0;
692}
693
694/* Handle the 'q' query packets */
695static void gdb_cmd_query(struct kgdb_state *ks)
696{
697 struct task_struct *g;
698 struct task_struct *p;
699 unsigned char thref[BUF_THREAD_ID_SIZE];
700 char *ptr;
701 int i;
702 int cpu;
703 int finished = 0;
704
705 switch (remcom_in_buffer[1]) {
706 case 's':
707 case 'f':
708 if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10))
709 break;
710
711 i = 0;
712 remcom_out_buffer[0] = 'm';
713 ptr = remcom_out_buffer + 1;
714 if (remcom_in_buffer[1] == 'f') {
715 /* Each cpu is a shadow thread */
716 for_each_online_cpu(cpu) {
717 ks->thr_query = 0;
718 int_to_threadref(thref, -cpu - 2);
719 ptr = pack_threadid(ptr, thref);
720 *(ptr++) = ',';
721 i++;
722 }
723 }
724
725 for_each_process_thread(g, p) {
726 if (i >= ks->thr_query && !finished) {
727 int_to_threadref(thref, p->pid);
728 ptr = pack_threadid(ptr, thref);
729 *(ptr++) = ',';
730 ks->thr_query++;
731 if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0)
732 finished = 1;
733 }
734 i++;
735 }
736
737 *(--ptr) = '\0';
738 break;
739
740 case 'C':
741 /* Current thread id */
742 strcpy(remcom_out_buffer, "QC");
743 ks->threadid = shadow_pid(current->pid);
744 int_to_threadref(thref, ks->threadid);
745 pack_threadid(remcom_out_buffer + 2, thref);
746 break;
747 case 'T':
748 if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16))
749 break;
750
751 ks->threadid = 0;
752 ptr = remcom_in_buffer + 17;
753 kgdb_hex2long(&ptr, &ks->threadid);
754 if (!getthread(ks->linux_regs, ks->threadid)) {
755 error_packet(remcom_out_buffer, -EINVAL);
756 break;
757 }
758 if ((int)ks->threadid > 0) {
759 kgdb_mem2hex(getthread(ks->linux_regs,
760 ks->threadid)->comm,
761 remcom_out_buffer, 16);
762 } else {
763 static char tmpstr[23 + BUF_THREAD_ID_SIZE];
764
765 sprintf(tmpstr, "shadowCPU%d",
766 (int)(-ks->threadid - 2));
767 kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr));
768 }
769 break;
770#ifdef CONFIG_KGDB_KDB
771 case 'R':
772 if (strncmp(remcom_in_buffer, "qRcmd,", 6) == 0) {
773 int len = strlen(remcom_in_buffer + 6);
774
775 if ((len % 2) != 0) {
776 strcpy(remcom_out_buffer, "E01");
777 break;
778 }
779 kgdb_hex2mem(remcom_in_buffer + 6,
780 remcom_out_buffer, len);
781 len = len / 2;
782 remcom_out_buffer[len++] = 0;
783
784 kdb_common_init_state(ks);
785 kdb_parse(remcom_out_buffer);
786 kdb_common_deinit_state();
787
788 strcpy(remcom_out_buffer, "OK");
789 }
790 break;
791#endif
792#ifdef CONFIG_HAVE_ARCH_KGDB_QXFER_PKT
793 case 'S':
794 if (!strncmp(remcom_in_buffer, "qSupported:", 11))
795 strcpy(remcom_out_buffer, kgdb_arch_gdb_stub_feature);
796 break;
797 case 'X':
798 if (!strncmp(remcom_in_buffer, "qXfer:", 6))
799 kgdb_arch_handle_qxfer_pkt(remcom_in_buffer,
800 remcom_out_buffer);
801 break;
802#endif
803 default:
804 break;
805 }
806}
807
808/* Handle the 'H' task query packets */
809static void gdb_cmd_task(struct kgdb_state *ks)
810{
811 struct task_struct *thread;
812 char *ptr;
813
814 switch (remcom_in_buffer[1]) {
815 case 'g':
816 ptr = &remcom_in_buffer[2];
817 kgdb_hex2long(&ptr, &ks->threadid);
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_usethread = thread;
824 ks->kgdb_usethreadid = ks->threadid;
825 strcpy(remcom_out_buffer, "OK");
826 break;
827 case 'c':
828 ptr = &remcom_in_buffer[2];
829 kgdb_hex2long(&ptr, &ks->threadid);
830 if (!ks->threadid) {
831 kgdb_contthread = NULL;
832 } else {
833 thread = getthread(ks->linux_regs, ks->threadid);
834 if (!thread && ks->threadid > 0) {
835 error_packet(remcom_out_buffer, -EINVAL);
836 break;
837 }
838 kgdb_contthread = thread;
839 }
840 strcpy(remcom_out_buffer, "OK");
841 break;
842 }
843}
844
845/* Handle the 'T' thread query packets */
846static void gdb_cmd_thread(struct kgdb_state *ks)
847{
848 char *ptr = &remcom_in_buffer[1];
849 struct task_struct *thread;
850
851 kgdb_hex2long(&ptr, &ks->threadid);
852 thread = getthread(ks->linux_regs, ks->threadid);
853 if (thread)
854 strcpy(remcom_out_buffer, "OK");
855 else
856 error_packet(remcom_out_buffer, -EINVAL);
857}
858
859/* Handle the 'z' or 'Z' breakpoint remove or set packets */
860static void gdb_cmd_break(struct kgdb_state *ks)
861{
862 /*
863 * Since GDB-5.3, it's been drafted that '0' is a software
864 * breakpoint, '1' is a hardware breakpoint, so let's do that.
865 */
866 char *bpt_type = &remcom_in_buffer[1];
867 char *ptr = &remcom_in_buffer[2];
868 unsigned long addr;
869 unsigned long length;
870 int error = 0;
871
872 if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') {
873 /* Unsupported */
874 if (*bpt_type > '4')
875 return;
876 } else {
877 if (*bpt_type != '0' && *bpt_type != '1')
878 /* Unsupported. */
879 return;
880 }
881
882 /*
883 * Test if this is a hardware breakpoint, and
884 * if we support it:
885 */
886 if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT))
887 /* Unsupported. */
888 return;
889
890 if (*(ptr++) != ',') {
891 error_packet(remcom_out_buffer, -EINVAL);
892 return;
893 }
894 if (!kgdb_hex2long(&ptr, &addr)) {
895 error_packet(remcom_out_buffer, -EINVAL);
896 return;
897 }
898 if (*(ptr++) != ',' ||
899 !kgdb_hex2long(&ptr, &length)) {
900 error_packet(remcom_out_buffer, -EINVAL);
901 return;
902 }
903
904 if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0')
905 error = dbg_set_sw_break(addr);
906 else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0')
907 error = dbg_remove_sw_break(addr);
908 else if (remcom_in_buffer[0] == 'Z')
909 error = arch_kgdb_ops.set_hw_breakpoint(addr,
910 (int)length, *bpt_type - '0');
911 else if (remcom_in_buffer[0] == 'z')
912 error = arch_kgdb_ops.remove_hw_breakpoint(addr,
913 (int) length, *bpt_type - '0');
914
915 if (error == 0)
916 strcpy(remcom_out_buffer, "OK");
917 else
918 error_packet(remcom_out_buffer, error);
919}
920
921/* Handle the 'C' signal / exception passing packets */
922static int gdb_cmd_exception_pass(struct kgdb_state *ks)
923{
924 /* C09 == pass exception
925 * C15 == detach kgdb, pass exception
926 */
927 if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') {
928
929 ks->pass_exception = 1;
930 remcom_in_buffer[0] = 'c';
931
932 } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') {
933
934 ks->pass_exception = 1;
935 remcom_in_buffer[0] = 'D';
936 dbg_remove_all_break();
937 kgdb_connected = 0;
938 return 1;
939
940 } else {
941 gdbstub_msg_write("KGDB only knows signal 9 (pass)"
942 " and 15 (pass and disconnect)\n"
943 "Executing a continue without signal passing\n", 0);
944 remcom_in_buffer[0] = 'c';
945 }
946
947 /* Indicate fall through */
948 return -1;
949}
950
951/*
952 * This function performs all gdbserial command processing
953 */
954int gdb_serial_stub(struct kgdb_state *ks)
955{
956 int error = 0;
957 int tmp;
958
959 /* Initialize comm buffer and globals. */
960 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
961 kgdb_usethread = kgdb_info[ks->cpu].task;
962 ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid);
963 ks->pass_exception = 0;
964
965 if (kgdb_connected) {
966 unsigned char thref[BUF_THREAD_ID_SIZE];
967 char *ptr;
968
969 /* Reply to host that an exception has occurred */
970 ptr = remcom_out_buffer;
971 *ptr++ = 'T';
972 ptr = hex_byte_pack(ptr, ks->signo);
973 ptr += strlen(strcpy(ptr, "thread:"));
974 int_to_threadref(thref, shadow_pid(current->pid));
975 ptr = pack_threadid(ptr, thref);
976 *ptr++ = ';';
977 put_packet(remcom_out_buffer);
978 }
979
980 while (1) {
981 error = 0;
982
983 /* Clear the out buffer. */
984 memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer));
985
986 get_packet(remcom_in_buffer);
987
988 switch (remcom_in_buffer[0]) {
989 case '?': /* gdbserial status */
990 gdb_cmd_status(ks);
991 break;
992 case 'g': /* return the value of the CPU registers */
993 gdb_cmd_getregs(ks);
994 break;
995 case 'G': /* set the value of the CPU registers - return OK */
996 gdb_cmd_setregs(ks);
997 break;
998 case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */
999 gdb_cmd_memread(ks);
1000 break;
1001 case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */
1002 gdb_cmd_memwrite(ks);
1003 break;
1004#if DBG_MAX_REG_NUM > 0
1005 case 'p': /* pXX Return gdb register XX (in hex) */
1006 gdb_cmd_reg_get(ks);
1007 break;
1008 case 'P': /* PXX=aaaa Set gdb register XX to aaaa (in hex) */
1009 gdb_cmd_reg_set(ks);
1010 break;
1011#endif /* DBG_MAX_REG_NUM > 0 */
1012 case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */
1013 gdb_cmd_binwrite(ks);
1014 break;
1015 /* kill or detach. KGDB should treat this like a
1016 * continue.
1017 */
1018 case 'D': /* Debugger detach */
1019 case 'k': /* Debugger detach via kill */
1020 gdb_cmd_detachkill(ks);
1021 goto default_handle;
1022 case 'R': /* Reboot */
1023 if (gdb_cmd_reboot(ks))
1024 goto default_handle;
1025 break;
1026 case 'q': /* query command */
1027 gdb_cmd_query(ks);
1028 break;
1029 case 'H': /* task related */
1030 gdb_cmd_task(ks);
1031 break;
1032 case 'T': /* Query thread status */
1033 gdb_cmd_thread(ks);
1034 break;
1035 case 'z': /* Break point remove */
1036 case 'Z': /* Break point set */
1037 gdb_cmd_break(ks);
1038 break;
1039#ifdef CONFIG_KGDB_KDB
1040 case '3': /* Escape into back into kdb */
1041 if (remcom_in_buffer[1] == '\0') {
1042 gdb_cmd_detachkill(ks);
1043 return DBG_PASS_EVENT;
1044 }
1045 fallthrough;
1046#endif
1047 case 'C': /* Exception passing */
1048 tmp = gdb_cmd_exception_pass(ks);
1049 if (tmp > 0)
1050 goto default_handle;
1051 if (tmp == 0)
1052 break;
1053 fallthrough; /* on tmp < 0 */
1054 case 'c': /* Continue packet */
1055 case 's': /* Single step packet */
1056 if (kgdb_contthread && kgdb_contthread != current) {
1057 /* Can't switch threads in kgdb */
1058 error_packet(remcom_out_buffer, -EINVAL);
1059 break;
1060 }
1061 fallthrough; /* to default processing */
1062 default:
1063default_handle:
1064 error = kgdb_arch_handle_exception(ks->ex_vector,
1065 ks->signo,
1066 ks->err_code,
1067 remcom_in_buffer,
1068 remcom_out_buffer,
1069 ks->linux_regs);
1070 /*
1071 * Leave cmd processing on error, detach,
1072 * kill, continue, or single step.
1073 */
1074 if (error >= 0 || remcom_in_buffer[0] == 'D' ||
1075 remcom_in_buffer[0] == 'k') {
1076 error = 0;
1077 goto kgdb_exit;
1078 }
1079
1080 }
1081
1082 /* reply to the request */
1083 put_packet(remcom_out_buffer);
1084 }
1085
1086kgdb_exit:
1087 if (ks->pass_exception)
1088 error = 1;
1089 return error;
1090}
1091
1092int gdbstub_state(struct kgdb_state *ks, char *cmd)
1093{
1094 int error;
1095
1096 switch (cmd[0]) {
1097 case 'e':
1098 error = kgdb_arch_handle_exception(ks->ex_vector,
1099 ks->signo,
1100 ks->err_code,
1101 remcom_in_buffer,
1102 remcom_out_buffer,
1103 ks->linux_regs);
1104 return error;
1105 case 's':
1106 case 'c':
1107 strscpy(remcom_in_buffer, cmd, sizeof(remcom_in_buffer));
1108 return 0;
1109 case '$':
1110 strscpy(remcom_in_buffer, cmd, sizeof(remcom_in_buffer));
1111 gdbstub_use_prev_in_buf = strlen(remcom_in_buffer);
1112 gdbstub_prev_in_buf_pos = 0;
1113 return 0;
1114 }
1115 dbg_io_ops->write_char('+');
1116 put_packet(remcom_out_buffer);
1117 return 0;
1118}
1119
1120/**
1121 * gdbstub_exit - Send an exit message to GDB
1122 * @status: The exit code to report.
1123 */
1124void gdbstub_exit(int status)
1125{
1126 unsigned char checksum, ch, buffer[3];
1127 int loop;
1128
1129 if (!kgdb_connected)
1130 return;
1131 kgdb_connected = 0;
1132
1133 if (!dbg_io_ops || dbg_kdb_mode)
1134 return;
1135
1136 buffer[0] = 'W';
1137 buffer[1] = hex_asc_hi(status);
1138 buffer[2] = hex_asc_lo(status);
1139
1140 dbg_io_ops->write_char('$');
1141 checksum = 0;
1142
1143 for (loop = 0; loop < 3; loop++) {
1144 ch = buffer[loop];
1145 checksum += ch;
1146 dbg_io_ops->write_char(ch);
1147 }
1148
1149 dbg_io_ops->write_char('#');
1150 dbg_io_ops->write_char(hex_asc_hi(checksum));
1151 dbg_io_ops->write_char(hex_asc_lo(checksum));
1152
1153 /* make sure the output is flushed, lest the bootloader clobber it */
1154 if (dbg_io_ops->flush)
1155 dbg_io_ops->flush();
1156}