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. */ |
42 | static char remcom_in_buffer[BUFMAX]; |
43 | static char remcom_out_buffer[BUFMAX]; |
44 | static int gdbstub_use_prev_in_buf; |
45 | static int gdbstub_prev_in_buf_pos; |
46 | |
47 | /* Storage for the registers, in GDB format. */ |
48 | static 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 |
57 | static 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 |
79 | static 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 $<data>#<checksum> */ |
88 | static void get_packet(char *buffer) |
89 | { |
90 | unsigned char checksum; |
91 | unsigned char xmitcsum; |
92 | int count; |
93 | char ch; |
94 | |
95 | do { |
96 | /* |
97 | * Spin and wait around for the start character, ignore all |
98 | * other characters: |
99 | */ |
100 | while ((ch = (gdbstub_read_wait())) != '$') |
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(ch: gdbstub_read_wait()) << 4; |
123 | xmitcsum += hex_to_bin(ch: 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 | */ |
142 | static 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 | |
193 | static char gdbmsgbuf[BUFMAX + 1]; |
194 | |
195 | void 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(buf: bufptr, byte: s[i]); |
220 | *bufptr = '\0'; |
221 | |
222 | /* Move up */ |
223 | s += wcount; |
224 | len -= wcount; |
225 | |
226 | /* Write packet */ |
227 | put_packet(buffer: 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 | */ |
236 | char *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(dst: tmp, src: mem, size: count); |
248 | if (err) |
249 | return NULL; |
250 | while (count > 0) { |
251 | buf = hex_byte_pack(buf, byte: *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 | */ |
265 | int 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(ch: *tmp_hex--); |
280 | *tmp_raw |= hex_to_bin(ch: *tmp_hex--) << 4; |
281 | } |
282 | |
283 | return copy_to_kernel_nofault(dst: mem, src: tmp_raw, size: count); |
284 | } |
285 | |
286 | /* |
287 | * While we find nice hex chars, build a long_val. |
288 | * Return number of chars processed. |
289 | */ |
290 | int 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(ch: **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 | */ |
323 | static 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(dst: mem, src: c, size); |
336 | } |
337 | |
338 | #if DBG_MAX_REG_NUM > 0 |
339 | void 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(regno: i, mem: ptr + idx, regs); |
347 | idx += dbg_reg_def[i].size; |
348 | } |
349 | } |
350 | |
351 | void 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(regno: i, mem: 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. */ |
365 | static 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: &ptr, long_val: &addr) > 0 && *(ptr++) == ',' && |
373 | kgdb_hex2long(ptr: &ptr, long_val: &length) > 0 && *(ptr++) == ':') { |
374 | if (binary) |
375 | err = kgdb_ebin2mem(buf: ptr, mem: (char *)addr, count: length); |
376 | else |
377 | err = kgdb_hex2mem(buf: ptr, mem: (char *)addr, count: length); |
378 | if (err) |
379 | return err; |
380 | if (CACHE_FLUSH_IS_SAFE) |
381 | flush_icache_range(start: addr, end: addr + length); |
382 | return 0; |
383 | } |
384 | |
385 | return -EINVAL; |
386 | } |
387 | |
388 | static 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 | |
405 | static 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(buf: pkt, byte: *id); |
414 | lzero = 0; |
415 | } |
416 | id++; |
417 | } |
418 | |
419 | if (lzero) |
420 | pkt = hex_byte_pack(buf: pkt, byte: 0); |
421 | |
422 | return pkt; |
423 | } |
424 | |
425 | static void int_to_threadref(unsigned char *id, int value) |
426 | { |
427 | put_unaligned_be32(val: value, p: id); |
428 | } |
429 | |
430 | static 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(v: &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(cpu: -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(nr: tid, ns: &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 | */ |
462 | static 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 */ |
477 | static 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(buf: &remcom_out_buffer[1], byte: ks->signo); |
489 | } |
490 | |
491 | static 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, 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, p: thread); |
531 | } |
532 | } |
533 | |
534 | /* Handle the 'g' get registers request */ |
535 | static void gdb_cmd_getregs(struct kgdb_state *ks) |
536 | { |
537 | gdb_get_regs_helper(ks); |
538 | kgdb_mem2hex(mem: (char *)gdb_regs, buf: remcom_out_buffer, NUMREGBYTES); |
539 | } |
540 | |
541 | /* Handle the 'G' set registers request */ |
542 | static void gdb_cmd_setregs(struct kgdb_state *ks) |
543 | { |
544 | kgdb_hex2mem(buf: &remcom_in_buffer[1], mem: (char *)gdb_regs, NUMREGBYTES); |
545 | |
546 | if (kgdb_usethread && kgdb_usethread != current) { |
547 | error_packet(pkt: remcom_out_buffer, error: -EINVAL); |
548 | } else { |
549 | gdb_regs_to_pt_regs(gdb_regs, regs: ks->linux_regs); |
550 | strcpy(p: remcom_out_buffer, q: "OK" ); |
551 | } |
552 | } |
553 | |
554 | /* Handle the 'm' memory read bytes */ |
555 | static 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: &ptr, long_val: &addr) > 0 && *ptr++ == ',' && |
563 | kgdb_hex2long(ptr: &ptr, long_val: &length) > 0) { |
564 | err = kgdb_mem2hex(mem: (char *)addr, buf: remcom_out_buffer, count: length); |
565 | if (!err) |
566 | error_packet(pkt: remcom_out_buffer, error: -EINVAL); |
567 | } else { |
568 | error_packet(pkt: remcom_out_buffer, error: -EINVAL); |
569 | } |
570 | } |
571 | |
572 | /* Handle the 'M' memory write bytes */ |
573 | static void gdb_cmd_memwrite(struct kgdb_state *ks) |
574 | { |
575 | int err = write_mem_msg(binary: 0); |
576 | |
577 | if (err) |
578 | error_packet(pkt: remcom_out_buffer, error: err); |
579 | else |
580 | strcpy(p: remcom_out_buffer, q: "OK" ); |
581 | } |
582 | |
583 | #if DBG_MAX_REG_NUM > 0 |
584 | static 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(mem: (char *)gdb_regs + offset, buf: out, |
592 | count: dbg_reg_def[i].size); |
593 | } |
594 | |
595 | /* Handle the 'p' individual register get */ |
596 | static 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: &ptr, long_val: ®num); |
602 | if (regnum >= DBG_MAX_REG_NUM) { |
603 | error_packet(pkt: remcom_out_buffer, error: -EINVAL); |
604 | return; |
605 | } |
606 | gdb_get_regs_helper(ks); |
607 | gdb_hex_reg_helper(regnum, out: remcom_out_buffer); |
608 | } |
609 | |
610 | /* Handle the 'P' individual register set */ |
611 | static 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: &ptr, long_val: ®num); |
618 | if (*ptr++ != '=' || |
619 | !(!kgdb_usethread || kgdb_usethread == current) || |
620 | !dbg_get_reg(regno: regnum, mem: gdb_regs, regs: ks->linux_regs)) { |
621 | error_packet(pkt: remcom_out_buffer, error: -EINVAL); |
622 | return; |
623 | } |
624 | memset(gdb_regs, 0, sizeof(gdb_regs)); |
625 | while (i < sizeof(gdb_regs) * 2) |
626 | if (hex_to_bin(ch: ptr[i]) >= 0) |
627 | i++; |
628 | else |
629 | break; |
630 | i = i / 2; |
631 | kgdb_hex2mem(buf: ptr, mem: (char *)gdb_regs, count: i); |
632 | dbg_set_reg(regno: regnum, mem: gdb_regs, regs: ks->linux_regs); |
633 | strcpy(p: remcom_out_buffer, q: "OK" ); |
634 | } |
635 | #endif /* DBG_MAX_REG_NUM > 0 */ |
636 | |
637 | /* Handle the 'X' memory binary write bytes */ |
638 | static void gdb_cmd_binwrite(struct kgdb_state *ks) |
639 | { |
640 | int err = write_mem_msg(binary: 1); |
641 | |
642 | if (err) |
643 | error_packet(pkt: remcom_out_buffer, error: err); |
644 | else |
645 | strcpy(p: remcom_out_buffer, q: "OK" ); |
646 | } |
647 | |
648 | /* Handle the 'D' or 'k', detach or kill packets */ |
649 | static 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(pkt: remcom_out_buffer, error); |
658 | } else { |
659 | strcpy(p: remcom_out_buffer, q: "OK" ); |
660 | kgdb_connected = 0; |
661 | } |
662 | put_packet(buffer: 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 */ |
674 | static 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(p: remcom_out_buffer, q: "OK" ); |
680 | put_packet(buffer: 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 */ |
695 | static 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(p: remcom_in_buffer + 2, q: "ThreadInfo" , size: 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(id: thref, value: -cpu - 2); |
719 | ptr = pack_threadid(pkt: ptr, id: 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(id: thref, value: p->pid); |
728 | ptr = pack_threadid(pkt: ptr, id: 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(p: remcom_out_buffer, q: "QC" ); |
743 | ks->threadid = shadow_pid(current->pid); |
744 | int_to_threadref(id: thref, value: ks->threadid); |
745 | pack_threadid(pkt: remcom_out_buffer + 2, id: thref); |
746 | break; |
747 | case 'T': |
748 | if (memcmp(p: remcom_in_buffer + 1, q: "ThreadExtraInfo," , size: 16)) |
749 | break; |
750 | |
751 | ks->threadid = 0; |
752 | ptr = remcom_in_buffer + 17; |
753 | kgdb_hex2long(ptr: &ptr, long_val: &ks->threadid); |
754 | if (!getthread(regs: ks->linux_regs, tid: ks->threadid)) { |
755 | error_packet(pkt: remcom_out_buffer, error: -EINVAL); |
756 | break; |
757 | } |
758 | if ((int)ks->threadid > 0) { |
759 | kgdb_mem2hex(mem: getthread(regs: ks->linux_regs, |
760 | tid: ks->threadid)->comm, |
761 | buf: remcom_out_buffer, count: 16); |
762 | } else { |
763 | static char tmpstr[23 + BUF_THREAD_ID_SIZE]; |
764 | |
765 | sprintf(buf: tmpstr, fmt: "shadowCPU%d" , |
766 | (int)(-ks->threadid - 2)); |
767 | kgdb_mem2hex(mem: tmpstr, buf: 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(p: remcom_out_buffer, q: "E01" ); |
777 | break; |
778 | } |
779 | kgdb_hex2mem(buf: remcom_in_buffer + 6, |
780 | mem: remcom_out_buffer, count: len); |
781 | len = len / 2; |
782 | remcom_out_buffer[len++] = 0; |
783 | |
784 | kdb_common_init_state(ks); |
785 | kdb_parse(cmdstr: remcom_out_buffer); |
786 | kdb_common_deinit_state(); |
787 | |
788 | strcpy(p: remcom_out_buffer, q: "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 */ |
809 | static 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: &ptr, long_val: &ks->threadid); |
818 | thread = getthread(regs: ks->linux_regs, tid: ks->threadid); |
819 | if (!thread && ks->threadid > 0) { |
820 | error_packet(pkt: remcom_out_buffer, error: -EINVAL); |
821 | break; |
822 | } |
823 | kgdb_usethread = thread; |
824 | ks->kgdb_usethreadid = ks->threadid; |
825 | strcpy(p: remcom_out_buffer, q: "OK" ); |
826 | break; |
827 | case 'c': |
828 | ptr = &remcom_in_buffer[2]; |
829 | kgdb_hex2long(ptr: &ptr, long_val: &ks->threadid); |
830 | if (!ks->threadid) { |
831 | kgdb_contthread = NULL; |
832 | } else { |
833 | thread = getthread(regs: ks->linux_regs, tid: ks->threadid); |
834 | if (!thread && ks->threadid > 0) { |
835 | error_packet(pkt: remcom_out_buffer, error: -EINVAL); |
836 | break; |
837 | } |
838 | kgdb_contthread = thread; |
839 | } |
840 | strcpy(p: remcom_out_buffer, q: "OK" ); |
841 | break; |
842 | } |
843 | } |
844 | |
845 | /* Handle the 'T' thread query packets */ |
846 | static 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: &ptr, long_val: &ks->threadid); |
852 | thread = getthread(regs: ks->linux_regs, tid: ks->threadid); |
853 | if (thread) |
854 | strcpy(p: remcom_out_buffer, q: "OK" ); |
855 | else |
856 | error_packet(pkt: remcom_out_buffer, error: -EINVAL); |
857 | } |
858 | |
859 | /* Handle the 'z' or 'Z' breakpoint remove or set packets */ |
860 | static 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(pkt: remcom_out_buffer, error: -EINVAL); |
892 | return; |
893 | } |
894 | if (!kgdb_hex2long(ptr: &ptr, long_val: &addr)) { |
895 | error_packet(pkt: remcom_out_buffer, error: -EINVAL); |
896 | return; |
897 | } |
898 | if (*(ptr++) != ',' || |
899 | !kgdb_hex2long(ptr: &ptr, long_val: &length)) { |
900 | error_packet(pkt: remcom_out_buffer, error: -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(p: remcom_out_buffer, q: "OK" ); |
917 | else |
918 | error_packet(pkt: remcom_out_buffer, error); |
919 | } |
920 | |
921 | /* Handle the 'C' signal / exception passing packets */ |
922 | static 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(s: "KGDB only knows signal 9 (pass)" |
942 | " and 15 (pass and disconnect)\n" |
943 | "Executing a continue without signal passing\n" , len: 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 | */ |
954 | int 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(realpid: 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(buf: ptr, byte: ks->signo); |
973 | ptr += strlen(strcpy(ptr, "thread:" )); |
974 | int_to_threadref(id: thref, value: shadow_pid(current->pid)); |
975 | ptr = pack_threadid(pkt: ptr, id: thref); |
976 | *ptr++ = ';'; |
977 | put_packet(buffer: 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(buffer: 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(pkt: remcom_out_buffer, error: -EINVAL); |
1059 | break; |
1060 | } |
1061 | fallthrough; /* to default processing */ |
1062 | default: |
1063 | default_handle: |
1064 | error = kgdb_arch_handle_exception(vector: ks->ex_vector, |
1065 | signo: ks->signo, |
1066 | err_code: ks->err_code, |
1067 | remcom_in_buffer, |
1068 | remcom_out_buffer, |
1069 | regs: 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(buffer: remcom_out_buffer); |
1084 | } |
1085 | |
1086 | kgdb_exit: |
1087 | if (ks->pass_exception) |
1088 | error = 1; |
1089 | return error; |
1090 | } |
1091 | |
1092 | int 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(vector: ks->ex_vector, |
1099 | signo: ks->signo, |
1100 | err_code: ks->err_code, |
1101 | remcom_in_buffer, |
1102 | remcom_out_buffer, |
1103 | regs: 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(buffer: 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 | */ |
1124 | void 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 | } |
1157 | |