Root/
1 | /* |
2 | * KGDB stub. |
3 | * |
4 | * Maintainer: Jason Wessel <jason.wessel@windriver.com> |
5 | * |
6 | * Copyright (C) 2000-2001 VERITAS Software Corporation. |
7 | * Copyright (C) 2002-2004 Timesys Corporation |
8 | * Copyright (C) 2003-2004 Amit S. Kale <amitkale@linsyssoft.com> |
9 | * Copyright (C) 2004 Pavel Machek <pavel@suse.cz> |
10 | * Copyright (C) 2004-2006 Tom Rini <trini@kernel.crashing.org> |
11 | * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd. |
12 | * Copyright (C) 2005-2008 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 | #include <linux/pid_namespace.h> |
31 | #include <linux/clocksource.h> |
32 | #include <linux/interrupt.h> |
33 | #include <linux/spinlock.h> |
34 | #include <linux/console.h> |
35 | #include <linux/threads.h> |
36 | #include <linux/uaccess.h> |
37 | #include <linux/kernel.h> |
38 | #include <linux/module.h> |
39 | #include <linux/ptrace.h> |
40 | #include <linux/reboot.h> |
41 | #include <linux/string.h> |
42 | #include <linux/delay.h> |
43 | #include <linux/sched.h> |
44 | #include <linux/sysrq.h> |
45 | #include <linux/init.h> |
46 | #include <linux/kgdb.h> |
47 | #include <linux/pid.h> |
48 | #include <linux/smp.h> |
49 | #include <linux/mm.h> |
50 | |
51 | #include <asm/cacheflush.h> |
52 | #include <asm/byteorder.h> |
53 | #include <asm/atomic.h> |
54 | #include <asm/system.h> |
55 | #include <asm/unaligned.h> |
56 | |
57 | static int kgdb_break_asap; |
58 | |
59 | #define KGDB_MAX_THREAD_QUERY 17 |
60 | struct kgdb_state { |
61 | int ex_vector; |
62 | int signo; |
63 | int err_code; |
64 | int cpu; |
65 | int pass_exception; |
66 | unsigned long thr_query; |
67 | unsigned long threadid; |
68 | long kgdb_usethreadid; |
69 | struct pt_regs *linux_regs; |
70 | }; |
71 | |
72 | /* Exception state values */ |
73 | #define DCPU_WANT_MASTER 0x1 /* Waiting to become a master kgdb cpu */ |
74 | #define DCPU_NEXT_MASTER 0x2 /* Transition from one master cpu to another */ |
75 | #define DCPU_IS_SLAVE 0x4 /* Slave cpu enter exception */ |
76 | #define DCPU_SSTEP 0x8 /* CPU is single stepping */ |
77 | |
78 | static struct debuggerinfo_struct { |
79 | void *debuggerinfo; |
80 | struct task_struct *task; |
81 | int exception_state; |
82 | } kgdb_info[NR_CPUS]; |
83 | |
84 | /** |
85 | * kgdb_connected - Is a host GDB connected to us? |
86 | */ |
87 | int kgdb_connected; |
88 | EXPORT_SYMBOL_GPL(kgdb_connected); |
89 | |
90 | /* All the KGDB handlers are installed */ |
91 | static int kgdb_io_module_registered; |
92 | |
93 | /* Guard for recursive entry */ |
94 | static int exception_level; |
95 | |
96 | static struct kgdb_io *kgdb_io_ops; |
97 | static DEFINE_SPINLOCK(kgdb_registration_lock); |
98 | |
99 | /* kgdb console driver is loaded */ |
100 | static int kgdb_con_registered; |
101 | /* determine if kgdb console output should be used */ |
102 | static int kgdb_use_con; |
103 | |
104 | static int __init opt_kgdb_con(char *str) |
105 | { |
106 | kgdb_use_con = 1; |
107 | return 0; |
108 | } |
109 | |
110 | early_param("kgdbcon", opt_kgdb_con); |
111 | |
112 | module_param(kgdb_use_con, int, 0644); |
113 | |
114 | /* |
115 | * Holds information about breakpoints in a kernel. These breakpoints are |
116 | * added and removed by gdb. |
117 | */ |
118 | static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = { |
119 | [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED } |
120 | }; |
121 | |
122 | /* |
123 | * The CPU# of the active CPU, or -1 if none: |
124 | */ |
125 | atomic_t kgdb_active = ATOMIC_INIT(-1); |
126 | |
127 | /* |
128 | * We use NR_CPUs not PERCPU, in case kgdb is used to debug early |
129 | * bootup code (which might not have percpu set up yet): |
130 | */ |
131 | static atomic_t passive_cpu_wait[NR_CPUS]; |
132 | static atomic_t cpu_in_kgdb[NR_CPUS]; |
133 | atomic_t kgdb_setting_breakpoint; |
134 | |
135 | struct task_struct *kgdb_usethread; |
136 | struct task_struct *kgdb_contthread; |
137 | |
138 | int kgdb_single_step; |
139 | pid_t kgdb_sstep_pid; |
140 | |
141 | /* Our I/O buffers. */ |
142 | static char remcom_in_buffer[BUFMAX]; |
143 | static char remcom_out_buffer[BUFMAX]; |
144 | |
145 | /* Storage for the registers, in GDB format. */ |
146 | static unsigned long gdb_regs[(NUMREGBYTES + |
147 | sizeof(unsigned long) - 1) / |
148 | sizeof(unsigned long)]; |
149 | |
150 | /* to keep track of the CPU which is doing the single stepping*/ |
151 | atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1); |
152 | |
153 | /* |
154 | * If you are debugging a problem where roundup (the collection of |
155 | * all other CPUs) is a problem [this should be extremely rare], |
156 | * then use the nokgdbroundup option to avoid roundup. In that case |
157 | * the other CPUs might interfere with your debugging context, so |
158 | * use this with care: |
159 | */ |
160 | static int kgdb_do_roundup = 1; |
161 | |
162 | static int __init opt_nokgdbroundup(char *str) |
163 | { |
164 | kgdb_do_roundup = 0; |
165 | |
166 | return 0; |
167 | } |
168 | |
169 | early_param("nokgdbroundup", opt_nokgdbroundup); |
170 | |
171 | /* |
172 | * Finally, some KGDB code :-) |
173 | */ |
174 | |
175 | /* |
176 | * Weak aliases for breakpoint management, |
177 | * can be overriden by architectures when needed: |
178 | */ |
179 | int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr) |
180 | { |
181 | int err; |
182 | |
183 | err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE); |
184 | if (err) |
185 | return err; |
186 | |
187 | return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr, |
188 | BREAK_INSTR_SIZE); |
189 | } |
190 | |
191 | int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle) |
192 | { |
193 | return probe_kernel_write((char *)addr, |
194 | (char *)bundle, BREAK_INSTR_SIZE); |
195 | } |
196 | |
197 | int __weak kgdb_validate_break_address(unsigned long addr) |
198 | { |
199 | char tmp_variable[BREAK_INSTR_SIZE]; |
200 | int err; |
201 | /* Validate setting the breakpoint and then removing it. In the |
202 | * remove fails, the kernel needs to emit a bad message because we |
203 | * are deep trouble not being able to put things back the way we |
204 | * found them. |
205 | */ |
206 | err = kgdb_arch_set_breakpoint(addr, tmp_variable); |
207 | if (err) |
208 | return err; |
209 | err = kgdb_arch_remove_breakpoint(addr, tmp_variable); |
210 | if (err) |
211 | printk(KERN_ERR "KGDB: Critical breakpoint error, kernel " |
212 | "memory destroyed at: %lx", addr); |
213 | return err; |
214 | } |
215 | |
216 | unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs) |
217 | { |
218 | return instruction_pointer(regs); |
219 | } |
220 | |
221 | int __weak kgdb_arch_init(void) |
222 | { |
223 | return 0; |
224 | } |
225 | |
226 | int __weak kgdb_skipexception(int exception, struct pt_regs *regs) |
227 | { |
228 | return 0; |
229 | } |
230 | |
231 | void __weak |
232 | kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code) |
233 | { |
234 | return; |
235 | } |
236 | |
237 | /** |
238 | * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb. |
239 | * @regs: Current &struct pt_regs. |
240 | * |
241 | * This function will be called if the particular architecture must |
242 | * disable hardware debugging while it is processing gdb packets or |
243 | * handling exception. |
244 | */ |
245 | void __weak kgdb_disable_hw_debug(struct pt_regs *regs) |
246 | { |
247 | } |
248 | |
249 | /* |
250 | * GDB remote protocol parser: |
251 | */ |
252 | |
253 | static int hex(char ch) |
254 | { |
255 | if ((ch >= 'a') && (ch <= 'f')) |
256 | return ch - 'a' + 10; |
257 | if ((ch >= '0') && (ch <= '9')) |
258 | return ch - '0'; |
259 | if ((ch >= 'A') && (ch <= 'F')) |
260 | return ch - 'A' + 10; |
261 | return -1; |
262 | } |
263 | |
264 | /* scan for the sequence $<data>#<checksum> */ |
265 | static void get_packet(char *buffer) |
266 | { |
267 | unsigned char checksum; |
268 | unsigned char xmitcsum; |
269 | int count; |
270 | char ch; |
271 | |
272 | do { |
273 | /* |
274 | * Spin and wait around for the start character, ignore all |
275 | * other characters: |
276 | */ |
277 | while ((ch = (kgdb_io_ops->read_char())) != '$') |
278 | /* nothing */; |
279 | |
280 | kgdb_connected = 1; |
281 | checksum = 0; |
282 | xmitcsum = -1; |
283 | |
284 | count = 0; |
285 | |
286 | /* |
287 | * now, read until a # or end of buffer is found: |
288 | */ |
289 | while (count < (BUFMAX - 1)) { |
290 | ch = kgdb_io_ops->read_char(); |
291 | if (ch == '#') |
292 | break; |
293 | checksum = checksum + ch; |
294 | buffer[count] = ch; |
295 | count = count + 1; |
296 | } |
297 | buffer[count] = 0; |
298 | |
299 | if (ch == '#') { |
300 | xmitcsum = hex(kgdb_io_ops->read_char()) << 4; |
301 | xmitcsum += hex(kgdb_io_ops->read_char()); |
302 | |
303 | if (checksum != xmitcsum) |
304 | /* failed checksum */ |
305 | kgdb_io_ops->write_char('-'); |
306 | else |
307 | /* successful transfer */ |
308 | kgdb_io_ops->write_char('+'); |
309 | if (kgdb_io_ops->flush) |
310 | kgdb_io_ops->flush(); |
311 | } |
312 | } while (checksum != xmitcsum); |
313 | } |
314 | |
315 | /* |
316 | * Send the packet in buffer. |
317 | * Check for gdb connection if asked for. |
318 | */ |
319 | static void put_packet(char *buffer) |
320 | { |
321 | unsigned char checksum; |
322 | int count; |
323 | char ch; |
324 | |
325 | /* |
326 | * $<packet info>#<checksum>. |
327 | */ |
328 | while (1) { |
329 | kgdb_io_ops->write_char('$'); |
330 | checksum = 0; |
331 | count = 0; |
332 | |
333 | while ((ch = buffer[count])) { |
334 | kgdb_io_ops->write_char(ch); |
335 | checksum += ch; |
336 | count++; |
337 | } |
338 | |
339 | kgdb_io_ops->write_char('#'); |
340 | kgdb_io_ops->write_char(hex_asc_hi(checksum)); |
341 | kgdb_io_ops->write_char(hex_asc_lo(checksum)); |
342 | if (kgdb_io_ops->flush) |
343 | kgdb_io_ops->flush(); |
344 | |
345 | /* Now see what we get in reply. */ |
346 | ch = kgdb_io_ops->read_char(); |
347 | |
348 | if (ch == 3) |
349 | ch = kgdb_io_ops->read_char(); |
350 | |
351 | /* If we get an ACK, we are done. */ |
352 | if (ch == '+') |
353 | return; |
354 | |
355 | /* |
356 | * If we get the start of another packet, this means |
357 | * that GDB is attempting to reconnect. We will NAK |
358 | * the packet being sent, and stop trying to send this |
359 | * packet. |
360 | */ |
361 | if (ch == '$') { |
362 | kgdb_io_ops->write_char('-'); |
363 | if (kgdb_io_ops->flush) |
364 | kgdb_io_ops->flush(); |
365 | return; |
366 | } |
367 | } |
368 | } |
369 | |
370 | /* |
371 | * Convert the memory pointed to by mem into hex, placing result in buf. |
372 | * Return a pointer to the last char put in buf (null). May return an error. |
373 | */ |
374 | int kgdb_mem2hex(char *mem, char *buf, int count) |
375 | { |
376 | char *tmp; |
377 | int err; |
378 | |
379 | /* |
380 | * We use the upper half of buf as an intermediate buffer for the |
381 | * raw memory copy. Hex conversion will work against this one. |
382 | */ |
383 | tmp = buf + count; |
384 | |
385 | err = probe_kernel_read(tmp, mem, count); |
386 | if (!err) { |
387 | while (count > 0) { |
388 | buf = pack_hex_byte(buf, *tmp); |
389 | tmp++; |
390 | count--; |
391 | } |
392 | |
393 | *buf = 0; |
394 | } |
395 | |
396 | return err; |
397 | } |
398 | |
399 | /* |
400 | * Copy the binary array pointed to by buf into mem. Fix $, #, and |
401 | * 0x7d escaped with 0x7d. Return -EFAULT on failure or 0 on success. |
402 | * The input buf is overwitten with the result to write to mem. |
403 | */ |
404 | static int kgdb_ebin2mem(char *buf, char *mem, int count) |
405 | { |
406 | int size = 0; |
407 | char *c = buf; |
408 | |
409 | while (count-- > 0) { |
410 | c[size] = *buf++; |
411 | if (c[size] == 0x7d) |
412 | c[size] = *buf++ ^ 0x20; |
413 | size++; |
414 | } |
415 | |
416 | return probe_kernel_write(mem, c, size); |
417 | } |
418 | |
419 | /* |
420 | * Convert the hex array pointed to by buf into binary to be placed in mem. |
421 | * Return a pointer to the character AFTER the last byte written. |
422 | * May return an error. |
423 | */ |
424 | int kgdb_hex2mem(char *buf, char *mem, int count) |
425 | { |
426 | char *tmp_raw; |
427 | char *tmp_hex; |
428 | |
429 | /* |
430 | * We use the upper half of buf as an intermediate buffer for the |
431 | * raw memory that is converted from hex. |
432 | */ |
433 | tmp_raw = buf + count * 2; |
434 | |
435 | tmp_hex = tmp_raw - 1; |
436 | while (tmp_hex >= buf) { |
437 | tmp_raw--; |
438 | *tmp_raw = hex(*tmp_hex--); |
439 | *tmp_raw |= hex(*tmp_hex--) << 4; |
440 | } |
441 | |
442 | return probe_kernel_write(mem, tmp_raw, count); |
443 | } |
444 | |
445 | /* |
446 | * While we find nice hex chars, build a long_val. |
447 | * Return number of chars processed. |
448 | */ |
449 | int kgdb_hex2long(char **ptr, unsigned long *long_val) |
450 | { |
451 | int hex_val; |
452 | int num = 0; |
453 | int negate = 0; |
454 | |
455 | *long_val = 0; |
456 | |
457 | if (**ptr == '-') { |
458 | negate = 1; |
459 | (*ptr)++; |
460 | } |
461 | while (**ptr) { |
462 | hex_val = hex(**ptr); |
463 | if (hex_val < 0) |
464 | break; |
465 | |
466 | *long_val = (*long_val << 4) | hex_val; |
467 | num++; |
468 | (*ptr)++; |
469 | } |
470 | |
471 | if (negate) |
472 | *long_val = -*long_val; |
473 | |
474 | return num; |
475 | } |
476 | |
477 | /* Write memory due to an 'M' or 'X' packet. */ |
478 | static int write_mem_msg(int binary) |
479 | { |
480 | char *ptr = &remcom_in_buffer[1]; |
481 | unsigned long addr; |
482 | unsigned long length; |
483 | int err; |
484 | |
485 | if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' && |
486 | kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') { |
487 | if (binary) |
488 | err = kgdb_ebin2mem(ptr, (char *)addr, length); |
489 | else |
490 | err = kgdb_hex2mem(ptr, (char *)addr, length); |
491 | if (err) |
492 | return err; |
493 | if (CACHE_FLUSH_IS_SAFE) |
494 | flush_icache_range(addr, addr + length); |
495 | return 0; |
496 | } |
497 | |
498 | return -EINVAL; |
499 | } |
500 | |
501 | static void error_packet(char *pkt, int error) |
502 | { |
503 | error = -error; |
504 | pkt[0] = 'E'; |
505 | pkt[1] = hex_asc[(error / 10)]; |
506 | pkt[2] = hex_asc[(error % 10)]; |
507 | pkt[3] = '\0'; |
508 | } |
509 | |
510 | /* |
511 | * Thread ID accessors. We represent a flat TID space to GDB, where |
512 | * the per CPU idle threads (which under Linux all have PID 0) are |
513 | * remapped to negative TIDs. |
514 | */ |
515 | |
516 | #define BUF_THREAD_ID_SIZE 16 |
517 | |
518 | static char *pack_threadid(char *pkt, unsigned char *id) |
519 | { |
520 | char *limit; |
521 | |
522 | limit = pkt + BUF_THREAD_ID_SIZE; |
523 | while (pkt < limit) |
524 | pkt = pack_hex_byte(pkt, *id++); |
525 | |
526 | return pkt; |
527 | } |
528 | |
529 | static void int_to_threadref(unsigned char *id, int value) |
530 | { |
531 | unsigned char *scan; |
532 | int i = 4; |
533 | |
534 | scan = (unsigned char *)id; |
535 | while (i--) |
536 | *scan++ = 0; |
537 | put_unaligned_be32(value, scan); |
538 | } |
539 | |
540 | static struct task_struct *getthread(struct pt_regs *regs, int tid) |
541 | { |
542 | /* |
543 | * Non-positive TIDs are remapped to the cpu shadow information |
544 | */ |
545 | if (tid == 0 || tid == -1) |
546 | tid = -atomic_read(&kgdb_active) - 2; |
547 | if (tid < -1 && tid > -NR_CPUS - 2) { |
548 | if (kgdb_info[-tid - 2].task) |
549 | return kgdb_info[-tid - 2].task; |
550 | else |
551 | return idle_task(-tid - 2); |
552 | } |
553 | if (tid <= 0) { |
554 | printk(KERN_ERR "KGDB: Internal thread select error\n"); |
555 | dump_stack(); |
556 | return NULL; |
557 | } |
558 | |
559 | /* |
560 | * find_task_by_pid_ns() does not take the tasklist lock anymore |
561 | * but is nicely RCU locked - hence is a pretty resilient |
562 | * thing to use: |
563 | */ |
564 | return find_task_by_pid_ns(tid, &init_pid_ns); |
565 | } |
566 | |
567 | /* |
568 | * Some architectures need cache flushes when we set/clear a |
569 | * breakpoint: |
570 | */ |
571 | static void kgdb_flush_swbreak_addr(unsigned long addr) |
572 | { |
573 | if (!CACHE_FLUSH_IS_SAFE) |
574 | return; |
575 | |
576 | if (current->mm && current->mm->mmap_cache) { |
577 | flush_cache_range(current->mm->mmap_cache, |
578 | addr, addr + BREAK_INSTR_SIZE); |
579 | } |
580 | /* Force flush instruction cache if it was outside the mm */ |
581 | flush_icache_range(addr, addr + BREAK_INSTR_SIZE); |
582 | } |
583 | |
584 | /* |
585 | * SW breakpoint management: |
586 | */ |
587 | static int kgdb_activate_sw_breakpoints(void) |
588 | { |
589 | unsigned long addr; |
590 | int error; |
591 | int ret = 0; |
592 | int i; |
593 | |
594 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
595 | if (kgdb_break[i].state != BP_SET) |
596 | continue; |
597 | |
598 | addr = kgdb_break[i].bpt_addr; |
599 | error = kgdb_arch_set_breakpoint(addr, |
600 | kgdb_break[i].saved_instr); |
601 | if (error) { |
602 | ret = error; |
603 | printk(KERN_INFO "KGDB: BP install failed: %lx", addr); |
604 | continue; |
605 | } |
606 | |
607 | kgdb_flush_swbreak_addr(addr); |
608 | kgdb_break[i].state = BP_ACTIVE; |
609 | } |
610 | return ret; |
611 | } |
612 | |
613 | static int kgdb_set_sw_break(unsigned long addr) |
614 | { |
615 | int err = kgdb_validate_break_address(addr); |
616 | int breakno = -1; |
617 | int i; |
618 | |
619 | if (err) |
620 | return err; |
621 | |
622 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
623 | if ((kgdb_break[i].state == BP_SET) && |
624 | (kgdb_break[i].bpt_addr == addr)) |
625 | return -EEXIST; |
626 | } |
627 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
628 | if (kgdb_break[i].state == BP_REMOVED && |
629 | kgdb_break[i].bpt_addr == addr) { |
630 | breakno = i; |
631 | break; |
632 | } |
633 | } |
634 | |
635 | if (breakno == -1) { |
636 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
637 | if (kgdb_break[i].state == BP_UNDEFINED) { |
638 | breakno = i; |
639 | break; |
640 | } |
641 | } |
642 | } |
643 | |
644 | if (breakno == -1) |
645 | return -E2BIG; |
646 | |
647 | kgdb_break[breakno].state = BP_SET; |
648 | kgdb_break[breakno].type = BP_BREAKPOINT; |
649 | kgdb_break[breakno].bpt_addr = addr; |
650 | |
651 | return 0; |
652 | } |
653 | |
654 | static int kgdb_deactivate_sw_breakpoints(void) |
655 | { |
656 | unsigned long addr; |
657 | int error; |
658 | int ret = 0; |
659 | int i; |
660 | |
661 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
662 | if (kgdb_break[i].state != BP_ACTIVE) |
663 | continue; |
664 | addr = kgdb_break[i].bpt_addr; |
665 | error = kgdb_arch_remove_breakpoint(addr, |
666 | kgdb_break[i].saved_instr); |
667 | if (error) { |
668 | printk(KERN_INFO "KGDB: BP remove failed: %lx\n", addr); |
669 | ret = error; |
670 | } |
671 | |
672 | kgdb_flush_swbreak_addr(addr); |
673 | kgdb_break[i].state = BP_SET; |
674 | } |
675 | return ret; |
676 | } |
677 | |
678 | static int kgdb_remove_sw_break(unsigned long addr) |
679 | { |
680 | int i; |
681 | |
682 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
683 | if ((kgdb_break[i].state == BP_SET) && |
684 | (kgdb_break[i].bpt_addr == addr)) { |
685 | kgdb_break[i].state = BP_REMOVED; |
686 | return 0; |
687 | } |
688 | } |
689 | return -ENOENT; |
690 | } |
691 | |
692 | int kgdb_isremovedbreak(unsigned long addr) |
693 | { |
694 | int i; |
695 | |
696 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
697 | if ((kgdb_break[i].state == BP_REMOVED) && |
698 | (kgdb_break[i].bpt_addr == addr)) |
699 | return 1; |
700 | } |
701 | return 0; |
702 | } |
703 | |
704 | static int remove_all_break(void) |
705 | { |
706 | unsigned long addr; |
707 | int error; |
708 | int i; |
709 | |
710 | /* Clear memory breakpoints. */ |
711 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { |
712 | if (kgdb_break[i].state != BP_ACTIVE) |
713 | goto setundefined; |
714 | addr = kgdb_break[i].bpt_addr; |
715 | error = kgdb_arch_remove_breakpoint(addr, |
716 | kgdb_break[i].saved_instr); |
717 | if (error) |
718 | printk(KERN_ERR "KGDB: breakpoint remove failed: %lx\n", |
719 | addr); |
720 | setundefined: |
721 | kgdb_break[i].state = BP_UNDEFINED; |
722 | } |
723 | |
724 | /* Clear hardware breakpoints. */ |
725 | if (arch_kgdb_ops.remove_all_hw_break) |
726 | arch_kgdb_ops.remove_all_hw_break(); |
727 | |
728 | return 0; |
729 | } |
730 | |
731 | /* |
732 | * Remap normal tasks to their real PID, |
733 | * CPU shadow threads are mapped to -CPU - 2 |
734 | */ |
735 | static inline int shadow_pid(int realpid) |
736 | { |
737 | if (realpid) |
738 | return realpid; |
739 | |
740 | return -raw_smp_processor_id() - 2; |
741 | } |
742 | |
743 | static char gdbmsgbuf[BUFMAX + 1]; |
744 | |
745 | static void kgdb_msg_write(const char *s, int len) |
746 | { |
747 | char *bufptr; |
748 | int wcount; |
749 | int i; |
750 | |
751 | /* 'O'utput */ |
752 | gdbmsgbuf[0] = 'O'; |
753 | |
754 | /* Fill and send buffers... */ |
755 | while (len > 0) { |
756 | bufptr = gdbmsgbuf + 1; |
757 | |
758 | /* Calculate how many this time */ |
759 | if ((len << 1) > (BUFMAX - 2)) |
760 | wcount = (BUFMAX - 2) >> 1; |
761 | else |
762 | wcount = len; |
763 | |
764 | /* Pack in hex chars */ |
765 | for (i = 0; i < wcount; i++) |
766 | bufptr = pack_hex_byte(bufptr, s[i]); |
767 | *bufptr = '\0'; |
768 | |
769 | /* Move up */ |
770 | s += wcount; |
771 | len -= wcount; |
772 | |
773 | /* Write packet */ |
774 | put_packet(gdbmsgbuf); |
775 | } |
776 | } |
777 | |
778 | /* |
779 | * Return true if there is a valid kgdb I/O module. Also if no |
780 | * debugger is attached a message can be printed to the console about |
781 | * waiting for the debugger to attach. |
782 | * |
783 | * The print_wait argument is only to be true when called from inside |
784 | * the core kgdb_handle_exception, because it will wait for the |
785 | * debugger to attach. |
786 | */ |
787 | static int kgdb_io_ready(int print_wait) |
788 | { |
789 | if (!kgdb_io_ops) |
790 | return 0; |
791 | if (kgdb_connected) |
792 | return 1; |
793 | if (atomic_read(&kgdb_setting_breakpoint)) |
794 | return 1; |
795 | if (print_wait) |
796 | printk(KERN_CRIT "KGDB: Waiting for remote debugger\n"); |
797 | return 1; |
798 | } |
799 | |
800 | /* |
801 | * All the functions that start with gdb_cmd are the various |
802 | * operations to implement the handlers for the gdbserial protocol |
803 | * where KGDB is communicating with an external debugger |
804 | */ |
805 | |
806 | /* Handle the '?' status packets */ |
807 | static void gdb_cmd_status(struct kgdb_state *ks) |
808 | { |
809 | /* |
810 | * We know that this packet is only sent |
811 | * during initial connect. So to be safe, |
812 | * we clear out our breakpoints now in case |
813 | * GDB is reconnecting. |
814 | */ |
815 | remove_all_break(); |
816 | |
817 | remcom_out_buffer[0] = 'S'; |
818 | pack_hex_byte(&remcom_out_buffer[1], ks->signo); |
819 | } |
820 | |
821 | /* Handle the 'g' get registers request */ |
822 | static void gdb_cmd_getregs(struct kgdb_state *ks) |
823 | { |
824 | struct task_struct *thread; |
825 | void *local_debuggerinfo; |
826 | int i; |
827 | |
828 | thread = kgdb_usethread; |
829 | if (!thread) { |
830 | thread = kgdb_info[ks->cpu].task; |
831 | local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo; |
832 | } else { |
833 | local_debuggerinfo = NULL; |
834 | for_each_online_cpu(i) { |
835 | /* |
836 | * Try to find the task on some other |
837 | * or possibly this node if we do not |
838 | * find the matching task then we try |
839 | * to approximate the results. |
840 | */ |
841 | if (thread == kgdb_info[i].task) |
842 | local_debuggerinfo = kgdb_info[i].debuggerinfo; |
843 | } |
844 | } |
845 | |
846 | /* |
847 | * All threads that don't have debuggerinfo should be |
848 | * in schedule() sleeping, since all other CPUs |
849 | * are in kgdb_wait, and thus have debuggerinfo. |
850 | */ |
851 | if (local_debuggerinfo) { |
852 | pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo); |
853 | } else { |
854 | /* |
855 | * Pull stuff saved during switch_to; nothing |
856 | * else is accessible (or even particularly |
857 | * relevant). |
858 | * |
859 | * This should be enough for a stack trace. |
860 | */ |
861 | sleeping_thread_to_gdb_regs(gdb_regs, thread); |
862 | } |
863 | kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES); |
864 | } |
865 | |
866 | /* Handle the 'G' set registers request */ |
867 | static void gdb_cmd_setregs(struct kgdb_state *ks) |
868 | { |
869 | kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES); |
870 | |
871 | if (kgdb_usethread && kgdb_usethread != current) { |
872 | error_packet(remcom_out_buffer, -EINVAL); |
873 | } else { |
874 | gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs); |
875 | strcpy(remcom_out_buffer, "OK"); |
876 | } |
877 | } |
878 | |
879 | /* Handle the 'm' memory read bytes */ |
880 | static void gdb_cmd_memread(struct kgdb_state *ks) |
881 | { |
882 | char *ptr = &remcom_in_buffer[1]; |
883 | unsigned long length; |
884 | unsigned long addr; |
885 | int err; |
886 | |
887 | if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' && |
888 | kgdb_hex2long(&ptr, &length) > 0) { |
889 | err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length); |
890 | if (err) |
891 | error_packet(remcom_out_buffer, err); |
892 | } else { |
893 | error_packet(remcom_out_buffer, -EINVAL); |
894 | } |
895 | } |
896 | |
897 | /* Handle the 'M' memory write bytes */ |
898 | static void gdb_cmd_memwrite(struct kgdb_state *ks) |
899 | { |
900 | int err = write_mem_msg(0); |
901 | |
902 | if (err) |
903 | error_packet(remcom_out_buffer, err); |
904 | else |
905 | strcpy(remcom_out_buffer, "OK"); |
906 | } |
907 | |
908 | /* Handle the 'X' memory binary write bytes */ |
909 | static void gdb_cmd_binwrite(struct kgdb_state *ks) |
910 | { |
911 | int err = write_mem_msg(1); |
912 | |
913 | if (err) |
914 | error_packet(remcom_out_buffer, err); |
915 | else |
916 | strcpy(remcom_out_buffer, "OK"); |
917 | } |
918 | |
919 | /* Handle the 'D' or 'k', detach or kill packets */ |
920 | static void gdb_cmd_detachkill(struct kgdb_state *ks) |
921 | { |
922 | int error; |
923 | |
924 | /* The detach case */ |
925 | if (remcom_in_buffer[0] == 'D') { |
926 | error = remove_all_break(); |
927 | if (error < 0) { |
928 | error_packet(remcom_out_buffer, error); |
929 | } else { |
930 | strcpy(remcom_out_buffer, "OK"); |
931 | kgdb_connected = 0; |
932 | } |
933 | put_packet(remcom_out_buffer); |
934 | } else { |
935 | /* |
936 | * Assume the kill case, with no exit code checking, |
937 | * trying to force detach the debugger: |
938 | */ |
939 | remove_all_break(); |
940 | kgdb_connected = 0; |
941 | } |
942 | } |
943 | |
944 | /* Handle the 'R' reboot packets */ |
945 | static int gdb_cmd_reboot(struct kgdb_state *ks) |
946 | { |
947 | /* For now, only honor R0 */ |
948 | if (strcmp(remcom_in_buffer, "R0") == 0) { |
949 | printk(KERN_CRIT "Executing emergency reboot\n"); |
950 | strcpy(remcom_out_buffer, "OK"); |
951 | put_packet(remcom_out_buffer); |
952 | |
953 | /* |
954 | * Execution should not return from |
955 | * machine_emergency_restart() |
956 | */ |
957 | machine_emergency_restart(); |
958 | kgdb_connected = 0; |
959 | |
960 | return 1; |
961 | } |
962 | return 0; |
963 | } |
964 | |
965 | /* Handle the 'q' query packets */ |
966 | static void gdb_cmd_query(struct kgdb_state *ks) |
967 | { |
968 | struct task_struct *g; |
969 | struct task_struct *p; |
970 | unsigned char thref[8]; |
971 | char *ptr; |
972 | int i; |
973 | int cpu; |
974 | int finished = 0; |
975 | |
976 | switch (remcom_in_buffer[1]) { |
977 | case 's': |
978 | case 'f': |
979 | if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) { |
980 | error_packet(remcom_out_buffer, -EINVAL); |
981 | break; |
982 | } |
983 | |
984 | i = 0; |
985 | remcom_out_buffer[0] = 'm'; |
986 | ptr = remcom_out_buffer + 1; |
987 | if (remcom_in_buffer[1] == 'f') { |
988 | /* Each cpu is a shadow thread */ |
989 | for_each_online_cpu(cpu) { |
990 | ks->thr_query = 0; |
991 | int_to_threadref(thref, -cpu - 2); |
992 | pack_threadid(ptr, thref); |
993 | ptr += BUF_THREAD_ID_SIZE; |
994 | *(ptr++) = ','; |
995 | i++; |
996 | } |
997 | } |
998 | |
999 | do_each_thread(g, p) { |
1000 | if (i >= ks->thr_query && !finished) { |
1001 | int_to_threadref(thref, p->pid); |
1002 | pack_threadid(ptr, thref); |
1003 | ptr += BUF_THREAD_ID_SIZE; |
1004 | *(ptr++) = ','; |
1005 | ks->thr_query++; |
1006 | if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0) |
1007 | finished = 1; |
1008 | } |
1009 | i++; |
1010 | } while_each_thread(g, p); |
1011 | |
1012 | *(--ptr) = '\0'; |
1013 | break; |
1014 | |
1015 | case 'C': |
1016 | /* Current thread id */ |
1017 | strcpy(remcom_out_buffer, "QC"); |
1018 | ks->threadid = shadow_pid(current->pid); |
1019 | int_to_threadref(thref, ks->threadid); |
1020 | pack_threadid(remcom_out_buffer + 2, thref); |
1021 | break; |
1022 | case 'T': |
1023 | if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) { |
1024 | error_packet(remcom_out_buffer, -EINVAL); |
1025 | break; |
1026 | } |
1027 | ks->threadid = 0; |
1028 | ptr = remcom_in_buffer + 17; |
1029 | kgdb_hex2long(&ptr, &ks->threadid); |
1030 | if (!getthread(ks->linux_regs, ks->threadid)) { |
1031 | error_packet(remcom_out_buffer, -EINVAL); |
1032 | break; |
1033 | } |
1034 | if ((int)ks->threadid > 0) { |
1035 | kgdb_mem2hex(getthread(ks->linux_regs, |
1036 | ks->threadid)->comm, |
1037 | remcom_out_buffer, 16); |
1038 | } else { |
1039 | static char tmpstr[23 + BUF_THREAD_ID_SIZE]; |
1040 | |
1041 | sprintf(tmpstr, "shadowCPU%d", |
1042 | (int)(-ks->threadid - 2)); |
1043 | kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr)); |
1044 | } |
1045 | break; |
1046 | } |
1047 | } |
1048 | |
1049 | /* Handle the 'H' task query packets */ |
1050 | static void gdb_cmd_task(struct kgdb_state *ks) |
1051 | { |
1052 | struct task_struct *thread; |
1053 | char *ptr; |
1054 | |
1055 | switch (remcom_in_buffer[1]) { |
1056 | case 'g': |
1057 | ptr = &remcom_in_buffer[2]; |
1058 | kgdb_hex2long(&ptr, &ks->threadid); |
1059 | thread = getthread(ks->linux_regs, ks->threadid); |
1060 | if (!thread && ks->threadid > 0) { |
1061 | error_packet(remcom_out_buffer, -EINVAL); |
1062 | break; |
1063 | } |
1064 | kgdb_usethread = thread; |
1065 | ks->kgdb_usethreadid = ks->threadid; |
1066 | strcpy(remcom_out_buffer, "OK"); |
1067 | break; |
1068 | case 'c': |
1069 | ptr = &remcom_in_buffer[2]; |
1070 | kgdb_hex2long(&ptr, &ks->threadid); |
1071 | if (!ks->threadid) { |
1072 | kgdb_contthread = NULL; |
1073 | } else { |
1074 | thread = getthread(ks->linux_regs, ks->threadid); |
1075 | if (!thread && ks->threadid > 0) { |
1076 | error_packet(remcom_out_buffer, -EINVAL); |
1077 | break; |
1078 | } |
1079 | kgdb_contthread = thread; |
1080 | } |
1081 | strcpy(remcom_out_buffer, "OK"); |
1082 | break; |
1083 | } |
1084 | } |
1085 | |
1086 | /* Handle the 'T' thread query packets */ |
1087 | static void gdb_cmd_thread(struct kgdb_state *ks) |
1088 | { |
1089 | char *ptr = &remcom_in_buffer[1]; |
1090 | struct task_struct *thread; |
1091 | |
1092 | kgdb_hex2long(&ptr, &ks->threadid); |
1093 | thread = getthread(ks->linux_regs, ks->threadid); |
1094 | if (thread) |
1095 | strcpy(remcom_out_buffer, "OK"); |
1096 | else |
1097 | error_packet(remcom_out_buffer, -EINVAL); |
1098 | } |
1099 | |
1100 | /* Handle the 'z' or 'Z' breakpoint remove or set packets */ |
1101 | static void gdb_cmd_break(struct kgdb_state *ks) |
1102 | { |
1103 | /* |
1104 | * Since GDB-5.3, it's been drafted that '0' is a software |
1105 | * breakpoint, '1' is a hardware breakpoint, so let's do that. |
1106 | */ |
1107 | char *bpt_type = &remcom_in_buffer[1]; |
1108 | char *ptr = &remcom_in_buffer[2]; |
1109 | unsigned long addr; |
1110 | unsigned long length; |
1111 | int error = 0; |
1112 | |
1113 | if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') { |
1114 | /* Unsupported */ |
1115 | if (*bpt_type > '4') |
1116 | return; |
1117 | } else { |
1118 | if (*bpt_type != '0' && *bpt_type != '1') |
1119 | /* Unsupported. */ |
1120 | return; |
1121 | } |
1122 | |
1123 | /* |
1124 | * Test if this is a hardware breakpoint, and |
1125 | * if we support it: |
1126 | */ |
1127 | if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT)) |
1128 | /* Unsupported. */ |
1129 | return; |
1130 | |
1131 | if (*(ptr++) != ',') { |
1132 | error_packet(remcom_out_buffer, -EINVAL); |
1133 | return; |
1134 | } |
1135 | if (!kgdb_hex2long(&ptr, &addr)) { |
1136 | error_packet(remcom_out_buffer, -EINVAL); |
1137 | return; |
1138 | } |
1139 | if (*(ptr++) != ',' || |
1140 | !kgdb_hex2long(&ptr, &length)) { |
1141 | error_packet(remcom_out_buffer, -EINVAL); |
1142 | return; |
1143 | } |
1144 | |
1145 | if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0') |
1146 | error = kgdb_set_sw_break(addr); |
1147 | else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0') |
1148 | error = kgdb_remove_sw_break(addr); |
1149 | else if (remcom_in_buffer[0] == 'Z') |
1150 | error = arch_kgdb_ops.set_hw_breakpoint(addr, |
1151 | (int)length, *bpt_type - '0'); |
1152 | else if (remcom_in_buffer[0] == 'z') |
1153 | error = arch_kgdb_ops.remove_hw_breakpoint(addr, |
1154 | (int) length, *bpt_type - '0'); |
1155 | |
1156 | if (error == 0) |
1157 | strcpy(remcom_out_buffer, "OK"); |
1158 | else |
1159 | error_packet(remcom_out_buffer, error); |
1160 | } |
1161 | |
1162 | /* Handle the 'C' signal / exception passing packets */ |
1163 | static int gdb_cmd_exception_pass(struct kgdb_state *ks) |
1164 | { |
1165 | /* C09 == pass exception |
1166 | * C15 == detach kgdb, pass exception |
1167 | */ |
1168 | if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') { |
1169 | |
1170 | ks->pass_exception = 1; |
1171 | remcom_in_buffer[0] = 'c'; |
1172 | |
1173 | } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') { |
1174 | |
1175 | ks->pass_exception = 1; |
1176 | remcom_in_buffer[0] = 'D'; |
1177 | remove_all_break(); |
1178 | kgdb_connected = 0; |
1179 | return 1; |
1180 | |
1181 | } else { |
1182 | kgdb_msg_write("KGDB only knows signal 9 (pass)" |
1183 | " and 15 (pass and disconnect)\n" |
1184 | "Executing a continue without signal passing\n", 0); |
1185 | remcom_in_buffer[0] = 'c'; |
1186 | } |
1187 | |
1188 | /* Indicate fall through */ |
1189 | return -1; |
1190 | } |
1191 | |
1192 | /* |
1193 | * This function performs all gdbserial command procesing |
1194 | */ |
1195 | static int gdb_serial_stub(struct kgdb_state *ks) |
1196 | { |
1197 | int error = 0; |
1198 | int tmp; |
1199 | |
1200 | /* Clear the out buffer. */ |
1201 | memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); |
1202 | |
1203 | if (kgdb_connected) { |
1204 | unsigned char thref[8]; |
1205 | char *ptr; |
1206 | |
1207 | /* Reply to host that an exception has occurred */ |
1208 | ptr = remcom_out_buffer; |
1209 | *ptr++ = 'T'; |
1210 | ptr = pack_hex_byte(ptr, ks->signo); |
1211 | ptr += strlen(strcpy(ptr, "thread:")); |
1212 | int_to_threadref(thref, shadow_pid(current->pid)); |
1213 | ptr = pack_threadid(ptr, thref); |
1214 | *ptr++ = ';'; |
1215 | put_packet(remcom_out_buffer); |
1216 | } |
1217 | |
1218 | kgdb_usethread = kgdb_info[ks->cpu].task; |
1219 | ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid); |
1220 | ks->pass_exception = 0; |
1221 | |
1222 | while (1) { |
1223 | error = 0; |
1224 | |
1225 | /* Clear the out buffer. */ |
1226 | memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); |
1227 | |
1228 | get_packet(remcom_in_buffer); |
1229 | |
1230 | switch (remcom_in_buffer[0]) { |
1231 | case '?': /* gdbserial status */ |
1232 | gdb_cmd_status(ks); |
1233 | break; |
1234 | case 'g': /* return the value of the CPU registers */ |
1235 | gdb_cmd_getregs(ks); |
1236 | break; |
1237 | case 'G': /* set the value of the CPU registers - return OK */ |
1238 | gdb_cmd_setregs(ks); |
1239 | break; |
1240 | case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ |
1241 | gdb_cmd_memread(ks); |
1242 | break; |
1243 | case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */ |
1244 | gdb_cmd_memwrite(ks); |
1245 | break; |
1246 | case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */ |
1247 | gdb_cmd_binwrite(ks); |
1248 | break; |
1249 | /* kill or detach. KGDB should treat this like a |
1250 | * continue. |
1251 | */ |
1252 | case 'D': /* Debugger detach */ |
1253 | case 'k': /* Debugger detach via kill */ |
1254 | gdb_cmd_detachkill(ks); |
1255 | goto default_handle; |
1256 | case 'R': /* Reboot */ |
1257 | if (gdb_cmd_reboot(ks)) |
1258 | goto default_handle; |
1259 | break; |
1260 | case 'q': /* query command */ |
1261 | gdb_cmd_query(ks); |
1262 | break; |
1263 | case 'H': /* task related */ |
1264 | gdb_cmd_task(ks); |
1265 | break; |
1266 | case 'T': /* Query thread status */ |
1267 | gdb_cmd_thread(ks); |
1268 | break; |
1269 | case 'z': /* Break point remove */ |
1270 | case 'Z': /* Break point set */ |
1271 | gdb_cmd_break(ks); |
1272 | break; |
1273 | case 'C': /* Exception passing */ |
1274 | tmp = gdb_cmd_exception_pass(ks); |
1275 | if (tmp > 0) |
1276 | goto default_handle; |
1277 | if (tmp == 0) |
1278 | break; |
1279 | /* Fall through on tmp < 0 */ |
1280 | case 'c': /* Continue packet */ |
1281 | case 's': /* Single step packet */ |
1282 | if (kgdb_contthread && kgdb_contthread != current) { |
1283 | /* Can't switch threads in kgdb */ |
1284 | error_packet(remcom_out_buffer, -EINVAL); |
1285 | break; |
1286 | } |
1287 | kgdb_activate_sw_breakpoints(); |
1288 | /* Fall through to default processing */ |
1289 | default: |
1290 | default_handle: |
1291 | error = kgdb_arch_handle_exception(ks->ex_vector, |
1292 | ks->signo, |
1293 | ks->err_code, |
1294 | remcom_in_buffer, |
1295 | remcom_out_buffer, |
1296 | ks->linux_regs); |
1297 | /* |
1298 | * Leave cmd processing on error, detach, |
1299 | * kill, continue, or single step. |
1300 | */ |
1301 | if (error >= 0 || remcom_in_buffer[0] == 'D' || |
1302 | remcom_in_buffer[0] == 'k') { |
1303 | error = 0; |
1304 | goto kgdb_exit; |
1305 | } |
1306 | |
1307 | } |
1308 | |
1309 | /* reply to the request */ |
1310 | put_packet(remcom_out_buffer); |
1311 | } |
1312 | |
1313 | kgdb_exit: |
1314 | if (ks->pass_exception) |
1315 | error = 1; |
1316 | return error; |
1317 | } |
1318 | |
1319 | static int kgdb_reenter_check(struct kgdb_state *ks) |
1320 | { |
1321 | unsigned long addr; |
1322 | |
1323 | if (atomic_read(&kgdb_active) != raw_smp_processor_id()) |
1324 | return 0; |
1325 | |
1326 | /* Panic on recursive debugger calls: */ |
1327 | exception_level++; |
1328 | addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs); |
1329 | kgdb_deactivate_sw_breakpoints(); |
1330 | |
1331 | /* |
1332 | * If the break point removed ok at the place exception |
1333 | * occurred, try to recover and print a warning to the end |
1334 | * user because the user planted a breakpoint in a place that |
1335 | * KGDB needs in order to function. |
1336 | */ |
1337 | if (kgdb_remove_sw_break(addr) == 0) { |
1338 | exception_level = 0; |
1339 | kgdb_skipexception(ks->ex_vector, ks->linux_regs); |
1340 | kgdb_activate_sw_breakpoints(); |
1341 | printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed %lx\n", |
1342 | addr); |
1343 | WARN_ON_ONCE(1); |
1344 | |
1345 | return 1; |
1346 | } |
1347 | remove_all_break(); |
1348 | kgdb_skipexception(ks->ex_vector, ks->linux_regs); |
1349 | |
1350 | if (exception_level > 1) { |
1351 | dump_stack(); |
1352 | panic("Recursive entry to debugger"); |
1353 | } |
1354 | |
1355 | printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n"); |
1356 | dump_stack(); |
1357 | panic("Recursive entry to debugger"); |
1358 | |
1359 | return 1; |
1360 | } |
1361 | |
1362 | static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs) |
1363 | { |
1364 | unsigned long flags; |
1365 | int sstep_tries = 100; |
1366 | int error = 0; |
1367 | int i, cpu; |
1368 | int trace_on = 0; |
1369 | acquirelock: |
1370 | /* |
1371 | * Interrupts will be restored by the 'trap return' code, except when |
1372 | * single stepping. |
1373 | */ |
1374 | local_irq_save(flags); |
1375 | |
1376 | cpu = ks->cpu; |
1377 | kgdb_info[cpu].debuggerinfo = regs; |
1378 | kgdb_info[cpu].task = current; |
1379 | /* |
1380 | * Make sure the above info reaches the primary CPU before |
1381 | * our cpu_in_kgdb[] flag setting does: |
1382 | */ |
1383 | atomic_inc(&cpu_in_kgdb[cpu]); |
1384 | |
1385 | /* |
1386 | * CPU will loop if it is a slave or request to become a kgdb |
1387 | * master cpu and acquire the kgdb_active lock: |
1388 | */ |
1389 | while (1) { |
1390 | if (kgdb_info[cpu].exception_state & DCPU_WANT_MASTER) { |
1391 | if (atomic_cmpxchg(&kgdb_active, -1, cpu) == cpu) |
1392 | break; |
1393 | } else if (kgdb_info[cpu].exception_state & DCPU_IS_SLAVE) { |
1394 | if (!atomic_read(&passive_cpu_wait[cpu])) |
1395 | goto return_normal; |
1396 | } else { |
1397 | return_normal: |
1398 | /* Return to normal operation by executing any |
1399 | * hw breakpoint fixup. |
1400 | */ |
1401 | if (arch_kgdb_ops.correct_hw_break) |
1402 | arch_kgdb_ops.correct_hw_break(); |
1403 | if (trace_on) |
1404 | tracing_on(); |
1405 | atomic_dec(&cpu_in_kgdb[cpu]); |
1406 | touch_softlockup_watchdog_sync(); |
1407 | clocksource_touch_watchdog(); |
1408 | local_irq_restore(flags); |
1409 | return 0; |
1410 | } |
1411 | cpu_relax(); |
1412 | } |
1413 | |
1414 | /* |
1415 | * For single stepping, try to only enter on the processor |
1416 | * that was single stepping. To gaurd against a deadlock, the |
1417 | * kernel will only try for the value of sstep_tries before |
1418 | * giving up and continuing on. |
1419 | */ |
1420 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1 && |
1421 | (kgdb_info[cpu].task && |
1422 | kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) { |
1423 | atomic_set(&kgdb_active, -1); |
1424 | touch_softlockup_watchdog_sync(); |
1425 | clocksource_touch_watchdog(); |
1426 | local_irq_restore(flags); |
1427 | |
1428 | goto acquirelock; |
1429 | } |
1430 | |
1431 | if (!kgdb_io_ready(1)) { |
1432 | error = 1; |
1433 | goto kgdb_restore; /* No I/O connection, so resume the system */ |
1434 | } |
1435 | |
1436 | /* |
1437 | * Don't enter if we have hit a removed breakpoint. |
1438 | */ |
1439 | if (kgdb_skipexception(ks->ex_vector, ks->linux_regs)) |
1440 | goto kgdb_restore; |
1441 | |
1442 | /* Call the I/O driver's pre_exception routine */ |
1443 | if (kgdb_io_ops->pre_exception) |
1444 | kgdb_io_ops->pre_exception(); |
1445 | |
1446 | kgdb_disable_hw_debug(ks->linux_regs); |
1447 | |
1448 | /* |
1449 | * Get the passive CPU lock which will hold all the non-primary |
1450 | * CPU in a spin state while the debugger is active |
1451 | */ |
1452 | if (!kgdb_single_step) { |
1453 | for (i = 0; i < NR_CPUS; i++) |
1454 | atomic_inc(&passive_cpu_wait[i]); |
1455 | } |
1456 | |
1457 | #ifdef CONFIG_SMP |
1458 | /* Signal the other CPUs to enter kgdb_wait() */ |
1459 | if ((!kgdb_single_step) && kgdb_do_roundup) |
1460 | kgdb_roundup_cpus(flags); |
1461 | #endif |
1462 | |
1463 | /* |
1464 | * Wait for the other CPUs to be notified and be waiting for us: |
1465 | */ |
1466 | for_each_online_cpu(i) { |
1467 | while (!atomic_read(&cpu_in_kgdb[i])) |
1468 | cpu_relax(); |
1469 | } |
1470 | |
1471 | /* |
1472 | * At this point the primary processor is completely |
1473 | * in the debugger and all secondary CPUs are quiescent |
1474 | */ |
1475 | kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code); |
1476 | kgdb_deactivate_sw_breakpoints(); |
1477 | kgdb_single_step = 0; |
1478 | kgdb_contthread = current; |
1479 | exception_level = 0; |
1480 | trace_on = tracing_is_on(); |
1481 | if (trace_on) |
1482 | tracing_off(); |
1483 | |
1484 | /* Talk to debugger with gdbserial protocol */ |
1485 | error = gdb_serial_stub(ks); |
1486 | |
1487 | /* Call the I/O driver's post_exception routine */ |
1488 | if (kgdb_io_ops->post_exception) |
1489 | kgdb_io_ops->post_exception(); |
1490 | |
1491 | atomic_dec(&cpu_in_kgdb[ks->cpu]); |
1492 | |
1493 | if (!kgdb_single_step) { |
1494 | for (i = NR_CPUS-1; i >= 0; i--) |
1495 | atomic_dec(&passive_cpu_wait[i]); |
1496 | /* |
1497 | * Wait till all the CPUs have quit |
1498 | * from the debugger. |
1499 | */ |
1500 | for_each_online_cpu(i) { |
1501 | while (atomic_read(&cpu_in_kgdb[i])) |
1502 | cpu_relax(); |
1503 | } |
1504 | } |
1505 | |
1506 | kgdb_restore: |
1507 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1) { |
1508 | int sstep_cpu = atomic_read(&kgdb_cpu_doing_single_step); |
1509 | if (kgdb_info[sstep_cpu].task) |
1510 | kgdb_sstep_pid = kgdb_info[sstep_cpu].task->pid; |
1511 | else |
1512 | kgdb_sstep_pid = 0; |
1513 | } |
1514 | if (trace_on) |
1515 | tracing_on(); |
1516 | /* Free kgdb_active */ |
1517 | atomic_set(&kgdb_active, -1); |
1518 | touch_softlockup_watchdog_sync(); |
1519 | clocksource_touch_watchdog(); |
1520 | local_irq_restore(flags); |
1521 | |
1522 | return error; |
1523 | } |
1524 | |
1525 | /* |
1526 | * kgdb_handle_exception() - main entry point from a kernel exception |
1527 | * |
1528 | * Locking hierarchy: |
1529 | * interface locks, if any (begin_session) |
1530 | * kgdb lock (kgdb_active) |
1531 | */ |
1532 | int |
1533 | kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) |
1534 | { |
1535 | struct kgdb_state kgdb_var; |
1536 | struct kgdb_state *ks = &kgdb_var; |
1537 | int ret; |
1538 | |
1539 | ks->cpu = raw_smp_processor_id(); |
1540 | ks->ex_vector = evector; |
1541 | ks->signo = signo; |
1542 | ks->ex_vector = evector; |
1543 | ks->err_code = ecode; |
1544 | ks->kgdb_usethreadid = 0; |
1545 | ks->linux_regs = regs; |
1546 | |
1547 | if (kgdb_reenter_check(ks)) |
1548 | return 0; /* Ouch, double exception ! */ |
1549 | kgdb_info[ks->cpu].exception_state |= DCPU_WANT_MASTER; |
1550 | ret = kgdb_cpu_enter(ks, regs); |
1551 | kgdb_info[ks->cpu].exception_state &= ~DCPU_WANT_MASTER; |
1552 | return ret; |
1553 | } |
1554 | |
1555 | int kgdb_nmicallback(int cpu, void *regs) |
1556 | { |
1557 | #ifdef CONFIG_SMP |
1558 | struct kgdb_state kgdb_var; |
1559 | struct kgdb_state *ks = &kgdb_var; |
1560 | |
1561 | memset(ks, 0, sizeof(struct kgdb_state)); |
1562 | ks->cpu = cpu; |
1563 | ks->linux_regs = regs; |
1564 | |
1565 | if (!atomic_read(&cpu_in_kgdb[cpu]) && |
1566 | atomic_read(&kgdb_active) != -1 && |
1567 | atomic_read(&kgdb_active) != cpu) { |
1568 | kgdb_info[cpu].exception_state |= DCPU_IS_SLAVE; |
1569 | kgdb_cpu_enter(ks, regs); |
1570 | kgdb_info[cpu].exception_state &= ~DCPU_IS_SLAVE; |
1571 | return 0; |
1572 | } |
1573 | #endif |
1574 | return 1; |
1575 | } |
1576 | |
1577 | static void kgdb_console_write(struct console *co, const char *s, |
1578 | unsigned count) |
1579 | { |
1580 | unsigned long flags; |
1581 | |
1582 | /* If we're debugging, or KGDB has not connected, don't try |
1583 | * and print. */ |
1584 | if (!kgdb_connected || atomic_read(&kgdb_active) != -1) |
1585 | return; |
1586 | |
1587 | local_irq_save(flags); |
1588 | kgdb_msg_write(s, count); |
1589 | local_irq_restore(flags); |
1590 | } |
1591 | |
1592 | static struct console kgdbcons = { |
1593 | .name = "kgdb", |
1594 | .write = kgdb_console_write, |
1595 | .flags = CON_PRINTBUFFER | CON_ENABLED, |
1596 | .index = -1, |
1597 | }; |
1598 | |
1599 | #ifdef CONFIG_MAGIC_SYSRQ |
1600 | static void sysrq_handle_gdb(int key, struct tty_struct *tty) |
1601 | { |
1602 | if (!kgdb_io_ops) { |
1603 | printk(KERN_CRIT "ERROR: No KGDB I/O module available\n"); |
1604 | return; |
1605 | } |
1606 | if (!kgdb_connected) |
1607 | printk(KERN_CRIT "Entering KGDB\n"); |
1608 | |
1609 | kgdb_breakpoint(); |
1610 | } |
1611 | |
1612 | static struct sysrq_key_op sysrq_gdb_op = { |
1613 | .handler = sysrq_handle_gdb, |
1614 | .help_msg = "debug(G)", |
1615 | .action_msg = "DEBUG", |
1616 | }; |
1617 | #endif |
1618 | |
1619 | static void kgdb_register_callbacks(void) |
1620 | { |
1621 | if (!kgdb_io_module_registered) { |
1622 | kgdb_io_module_registered = 1; |
1623 | kgdb_arch_init(); |
1624 | #ifdef CONFIG_MAGIC_SYSRQ |
1625 | register_sysrq_key('g', &sysrq_gdb_op); |
1626 | #endif |
1627 | if (kgdb_use_con && !kgdb_con_registered) { |
1628 | register_console(&kgdbcons); |
1629 | kgdb_con_registered = 1; |
1630 | } |
1631 | } |
1632 | } |
1633 | |
1634 | static void kgdb_unregister_callbacks(void) |
1635 | { |
1636 | /* |
1637 | * When this routine is called KGDB should unregister from the |
1638 | * panic handler and clean up, making sure it is not handling any |
1639 | * break exceptions at the time. |
1640 | */ |
1641 | if (kgdb_io_module_registered) { |
1642 | kgdb_io_module_registered = 0; |
1643 | kgdb_arch_exit(); |
1644 | #ifdef CONFIG_MAGIC_SYSRQ |
1645 | unregister_sysrq_key('g', &sysrq_gdb_op); |
1646 | #endif |
1647 | if (kgdb_con_registered) { |
1648 | unregister_console(&kgdbcons); |
1649 | kgdb_con_registered = 0; |
1650 | } |
1651 | } |
1652 | } |
1653 | |
1654 | static void kgdb_initial_breakpoint(void) |
1655 | { |
1656 | kgdb_break_asap = 0; |
1657 | |
1658 | printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n"); |
1659 | kgdb_breakpoint(); |
1660 | } |
1661 | |
1662 | /** |
1663 | * kgdb_register_io_module - register KGDB IO module |
1664 | * @new_kgdb_io_ops: the io ops vector |
1665 | * |
1666 | * Register it with the KGDB core. |
1667 | */ |
1668 | int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops) |
1669 | { |
1670 | int err; |
1671 | |
1672 | spin_lock(&kgdb_registration_lock); |
1673 | |
1674 | if (kgdb_io_ops) { |
1675 | spin_unlock(&kgdb_registration_lock); |
1676 | |
1677 | printk(KERN_ERR "kgdb: Another I/O driver is already " |
1678 | "registered with KGDB.\n"); |
1679 | return -EBUSY; |
1680 | } |
1681 | |
1682 | if (new_kgdb_io_ops->init) { |
1683 | err = new_kgdb_io_ops->init(); |
1684 | if (err) { |
1685 | spin_unlock(&kgdb_registration_lock); |
1686 | return err; |
1687 | } |
1688 | } |
1689 | |
1690 | kgdb_io_ops = new_kgdb_io_ops; |
1691 | |
1692 | spin_unlock(&kgdb_registration_lock); |
1693 | |
1694 | printk(KERN_INFO "kgdb: Registered I/O driver %s.\n", |
1695 | new_kgdb_io_ops->name); |
1696 | |
1697 | /* Arm KGDB now. */ |
1698 | kgdb_register_callbacks(); |
1699 | |
1700 | if (kgdb_break_asap) |
1701 | kgdb_initial_breakpoint(); |
1702 | |
1703 | return 0; |
1704 | } |
1705 | EXPORT_SYMBOL_GPL(kgdb_register_io_module); |
1706 | |
1707 | /** |
1708 | * kkgdb_unregister_io_module - unregister KGDB IO module |
1709 | * @old_kgdb_io_ops: the io ops vector |
1710 | * |
1711 | * Unregister it with the KGDB core. |
1712 | */ |
1713 | void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops) |
1714 | { |
1715 | BUG_ON(kgdb_connected); |
1716 | |
1717 | /* |
1718 | * KGDB is no longer able to communicate out, so |
1719 | * unregister our callbacks and reset state. |
1720 | */ |
1721 | kgdb_unregister_callbacks(); |
1722 | |
1723 | spin_lock(&kgdb_registration_lock); |
1724 | |
1725 | WARN_ON_ONCE(kgdb_io_ops != old_kgdb_io_ops); |
1726 | kgdb_io_ops = NULL; |
1727 | |
1728 | spin_unlock(&kgdb_registration_lock); |
1729 | |
1730 | printk(KERN_INFO |
1731 | "kgdb: Unregistered I/O driver %s, debugger disabled.\n", |
1732 | old_kgdb_io_ops->name); |
1733 | } |
1734 | EXPORT_SYMBOL_GPL(kgdb_unregister_io_module); |
1735 | |
1736 | /** |
1737 | * kgdb_breakpoint - generate breakpoint exception |
1738 | * |
1739 | * This function will generate a breakpoint exception. It is used at the |
1740 | * beginning of a program to sync up with a debugger and can be used |
1741 | * otherwise as a quick means to stop program execution and "break" into |
1742 | * the debugger. |
1743 | */ |
1744 | void kgdb_breakpoint(void) |
1745 | { |
1746 | atomic_inc(&kgdb_setting_breakpoint); |
1747 | wmb(); /* Sync point before breakpoint */ |
1748 | arch_kgdb_breakpoint(); |
1749 | wmb(); /* Sync point after breakpoint */ |
1750 | atomic_dec(&kgdb_setting_breakpoint); |
1751 | } |
1752 | EXPORT_SYMBOL_GPL(kgdb_breakpoint); |
1753 | |
1754 | static int __init opt_kgdb_wait(char *str) |
1755 | { |
1756 | kgdb_break_asap = 1; |
1757 | |
1758 | if (kgdb_io_module_registered) |
1759 | kgdb_initial_breakpoint(); |
1760 | |
1761 | return 0; |
1762 | } |
1763 | |
1764 | early_param("kgdbwait", opt_kgdb_wait); |
1765 |
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