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dc7d5527 JW |
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> | |
7c3078b6 | 31 | #include <linux/clocksource.h> |
dc7d5527 JW |
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> | |
827e609b | 55 | #include <asm/unaligned.h> |
dc7d5527 JW |
56 | |
57 | static int kgdb_break_asap; | |
58 | ||
25fc9999 | 59 | #define KGDB_MAX_THREAD_QUERY 17 |
dc7d5527 JW |
60 | struct kgdb_state { |
61 | int ex_vector; | |
62 | int signo; | |
63 | int err_code; | |
64 | int cpu; | |
65 | int pass_exception; | |
25fc9999 | 66 | unsigned long thr_query; |
688b744d | 67 | unsigned long threadid; |
dc7d5527 JW |
68 | long kgdb_usethreadid; |
69 | struct pt_regs *linux_regs; | |
70 | }; | |
71 | ||
72 | static struct debuggerinfo_struct { | |
73 | void *debuggerinfo; | |
74 | struct task_struct *task; | |
75 | } kgdb_info[NR_CPUS]; | |
76 | ||
77 | /** | |
78 | * kgdb_connected - Is a host GDB connected to us? | |
79 | */ | |
80 | int kgdb_connected; | |
81 | EXPORT_SYMBOL_GPL(kgdb_connected); | |
82 | ||
83 | /* All the KGDB handlers are installed */ | |
84 | static int kgdb_io_module_registered; | |
85 | ||
86 | /* Guard for recursive entry */ | |
87 | static int exception_level; | |
88 | ||
89 | static struct kgdb_io *kgdb_io_ops; | |
90 | static DEFINE_SPINLOCK(kgdb_registration_lock); | |
91 | ||
92 | /* kgdb console driver is loaded */ | |
93 | static int kgdb_con_registered; | |
94 | /* determine if kgdb console output should be used */ | |
95 | static int kgdb_use_con; | |
96 | ||
97 | static int __init opt_kgdb_con(char *str) | |
98 | { | |
99 | kgdb_use_con = 1; | |
100 | return 0; | |
101 | } | |
102 | ||
103 | early_param("kgdbcon", opt_kgdb_con); | |
104 | ||
105 | module_param(kgdb_use_con, int, 0644); | |
106 | ||
107 | /* | |
108 | * Holds information about breakpoints in a kernel. These breakpoints are | |
109 | * added and removed by gdb. | |
110 | */ | |
111 | static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = { | |
112 | [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED } | |
113 | }; | |
114 | ||
115 | /* | |
116 | * The CPU# of the active CPU, or -1 if none: | |
117 | */ | |
118 | atomic_t kgdb_active = ATOMIC_INIT(-1); | |
119 | ||
120 | /* | |
121 | * We use NR_CPUs not PERCPU, in case kgdb is used to debug early | |
122 | * bootup code (which might not have percpu set up yet): | |
123 | */ | |
124 | static atomic_t passive_cpu_wait[NR_CPUS]; | |
125 | static atomic_t cpu_in_kgdb[NR_CPUS]; | |
126 | atomic_t kgdb_setting_breakpoint; | |
127 | ||
128 | struct task_struct *kgdb_usethread; | |
129 | struct task_struct *kgdb_contthread; | |
130 | ||
131 | int kgdb_single_step; | |
132 | ||
133 | /* Our I/O buffers. */ | |
134 | static char remcom_in_buffer[BUFMAX]; | |
135 | static char remcom_out_buffer[BUFMAX]; | |
136 | ||
137 | /* Storage for the registers, in GDB format. */ | |
138 | static unsigned long gdb_regs[(NUMREGBYTES + | |
139 | sizeof(unsigned long) - 1) / | |
140 | sizeof(unsigned long)]; | |
141 | ||
142 | /* to keep track of the CPU which is doing the single stepping*/ | |
143 | atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1); | |
144 | ||
145 | /* | |
146 | * If you are debugging a problem where roundup (the collection of | |
147 | * all other CPUs) is a problem [this should be extremely rare], | |
148 | * then use the nokgdbroundup option to avoid roundup. In that case | |
149 | * the other CPUs might interfere with your debugging context, so | |
150 | * use this with care: | |
151 | */ | |
688b744d | 152 | static int kgdb_do_roundup = 1; |
dc7d5527 JW |
153 | |
154 | static int __init opt_nokgdbroundup(char *str) | |
155 | { | |
156 | kgdb_do_roundup = 0; | |
157 | ||
158 | return 0; | |
159 | } | |
160 | ||
161 | early_param("nokgdbroundup", opt_nokgdbroundup); | |
162 | ||
163 | /* | |
164 | * Finally, some KGDB code :-) | |
165 | */ | |
166 | ||
167 | /* | |
168 | * Weak aliases for breakpoint management, | |
169 | * can be overriden by architectures when needed: | |
170 | */ | |
dc7d5527 JW |
171 | int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr) |
172 | { | |
173 | int err; | |
174 | ||
175 | err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE); | |
176 | if (err) | |
177 | return err; | |
178 | ||
179 | return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr, | |
180 | BREAK_INSTR_SIZE); | |
181 | } | |
182 | ||
183 | int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle) | |
184 | { | |
185 | return probe_kernel_write((char *)addr, | |
186 | (char *)bundle, BREAK_INSTR_SIZE); | |
187 | } | |
188 | ||
a9b60bf4 JW |
189 | int __weak kgdb_validate_break_address(unsigned long addr) |
190 | { | |
191 | char tmp_variable[BREAK_INSTR_SIZE]; | |
192 | int err; | |
193 | /* Validate setting the breakpoint and then removing it. In the | |
194 | * remove fails, the kernel needs to emit a bad message because we | |
195 | * are deep trouble not being able to put things back the way we | |
196 | * found them. | |
197 | */ | |
198 | err = kgdb_arch_set_breakpoint(addr, tmp_variable); | |
199 | if (err) | |
200 | return err; | |
201 | err = kgdb_arch_remove_breakpoint(addr, tmp_variable); | |
202 | if (err) | |
203 | printk(KERN_ERR "KGDB: Critical breakpoint error, kernel " | |
204 | "memory destroyed at: %lx", addr); | |
205 | return err; | |
206 | } | |
207 | ||
dc7d5527 JW |
208 | unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs) |
209 | { | |
210 | return instruction_pointer(regs); | |
211 | } | |
212 | ||
213 | int __weak kgdb_arch_init(void) | |
214 | { | |
215 | return 0; | |
216 | } | |
217 | ||
b4b8ac52 JW |
218 | int __weak kgdb_skipexception(int exception, struct pt_regs *regs) |
219 | { | |
220 | return 0; | |
221 | } | |
222 | ||
223 | void __weak | |
224 | kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code) | |
225 | { | |
226 | return; | |
227 | } | |
228 | ||
dc7d5527 JW |
229 | /** |
230 | * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb. | |
231 | * @regs: Current &struct pt_regs. | |
232 | * | |
233 | * This function will be called if the particular architecture must | |
234 | * disable hardware debugging while it is processing gdb packets or | |
235 | * handling exception. | |
236 | */ | |
237 | void __weak kgdb_disable_hw_debug(struct pt_regs *regs) | |
238 | { | |
239 | } | |
240 | ||
241 | /* | |
242 | * GDB remote protocol parser: | |
243 | */ | |
244 | ||
dc7d5527 JW |
245 | static int hex(char ch) |
246 | { | |
247 | if ((ch >= 'a') && (ch <= 'f')) | |
248 | return ch - 'a' + 10; | |
249 | if ((ch >= '0') && (ch <= '9')) | |
250 | return ch - '0'; | |
251 | if ((ch >= 'A') && (ch <= 'F')) | |
252 | return ch - 'A' + 10; | |
253 | return -1; | |
254 | } | |
255 | ||
256 | /* scan for the sequence $<data>#<checksum> */ | |
257 | static void get_packet(char *buffer) | |
258 | { | |
259 | unsigned char checksum; | |
260 | unsigned char xmitcsum; | |
261 | int count; | |
262 | char ch; | |
263 | ||
264 | do { | |
265 | /* | |
266 | * Spin and wait around for the start character, ignore all | |
267 | * other characters: | |
268 | */ | |
269 | while ((ch = (kgdb_io_ops->read_char())) != '$') | |
270 | /* nothing */; | |
271 | ||
272 | kgdb_connected = 1; | |
273 | checksum = 0; | |
274 | xmitcsum = -1; | |
275 | ||
276 | count = 0; | |
277 | ||
278 | /* | |
279 | * now, read until a # or end of buffer is found: | |
280 | */ | |
281 | while (count < (BUFMAX - 1)) { | |
282 | ch = kgdb_io_ops->read_char(); | |
283 | if (ch == '#') | |
284 | break; | |
285 | checksum = checksum + ch; | |
286 | buffer[count] = ch; | |
287 | count = count + 1; | |
288 | } | |
289 | buffer[count] = 0; | |
290 | ||
291 | if (ch == '#') { | |
292 | xmitcsum = hex(kgdb_io_ops->read_char()) << 4; | |
293 | xmitcsum += hex(kgdb_io_ops->read_char()); | |
294 | ||
295 | if (checksum != xmitcsum) | |
296 | /* failed checksum */ | |
297 | kgdb_io_ops->write_char('-'); | |
298 | else | |
299 | /* successful transfer */ | |
300 | kgdb_io_ops->write_char('+'); | |
301 | if (kgdb_io_ops->flush) | |
302 | kgdb_io_ops->flush(); | |
303 | } | |
304 | } while (checksum != xmitcsum); | |
305 | } | |
306 | ||
307 | /* | |
308 | * Send the packet in buffer. | |
309 | * Check for gdb connection if asked for. | |
310 | */ | |
311 | static void put_packet(char *buffer) | |
312 | { | |
313 | unsigned char checksum; | |
314 | int count; | |
315 | char ch; | |
316 | ||
317 | /* | |
318 | * $<packet info>#<checksum>. | |
319 | */ | |
320 | while (1) { | |
321 | kgdb_io_ops->write_char('$'); | |
322 | checksum = 0; | |
323 | count = 0; | |
324 | ||
325 | while ((ch = buffer[count])) { | |
326 | kgdb_io_ops->write_char(ch); | |
327 | checksum += ch; | |
328 | count++; | |
329 | } | |
330 | ||
331 | kgdb_io_ops->write_char('#'); | |
827e609b HH |
332 | kgdb_io_ops->write_char(hex_asc_hi(checksum)); |
333 | kgdb_io_ops->write_char(hex_asc_lo(checksum)); | |
dc7d5527 JW |
334 | if (kgdb_io_ops->flush) |
335 | kgdb_io_ops->flush(); | |
336 | ||
337 | /* Now see what we get in reply. */ | |
338 | ch = kgdb_io_ops->read_char(); | |
339 | ||
340 | if (ch == 3) | |
341 | ch = kgdb_io_ops->read_char(); | |
342 | ||
343 | /* If we get an ACK, we are done. */ | |
344 | if (ch == '+') | |
345 | return; | |
346 | ||
347 | /* | |
348 | * If we get the start of another packet, this means | |
349 | * that GDB is attempting to reconnect. We will NAK | |
350 | * the packet being sent, and stop trying to send this | |
351 | * packet. | |
352 | */ | |
353 | if (ch == '$') { | |
354 | kgdb_io_ops->write_char('-'); | |
355 | if (kgdb_io_ops->flush) | |
356 | kgdb_io_ops->flush(); | |
357 | return; | |
358 | } | |
359 | } | |
360 | } | |
361 | ||
dc7d5527 JW |
362 | /* |
363 | * Convert the memory pointed to by mem into hex, placing result in buf. | |
364 | * Return a pointer to the last char put in buf (null). May return an error. | |
365 | */ | |
366 | int kgdb_mem2hex(char *mem, char *buf, int count) | |
367 | { | |
368 | char *tmp; | |
369 | int err; | |
370 | ||
371 | /* | |
372 | * We use the upper half of buf as an intermediate buffer for the | |
373 | * raw memory copy. Hex conversion will work against this one. | |
374 | */ | |
375 | tmp = buf + count; | |
376 | ||
377 | err = probe_kernel_read(tmp, mem, count); | |
378 | if (!err) { | |
379 | while (count > 0) { | |
380 | buf = pack_hex_byte(buf, *tmp); | |
381 | tmp++; | |
382 | count--; | |
383 | } | |
384 | ||
385 | *buf = 0; | |
386 | } | |
387 | ||
388 | return err; | |
389 | } | |
390 | ||
391 | /* | |
392 | * Copy the binary array pointed to by buf into mem. Fix $, #, and | |
393 | * 0x7d escaped with 0x7d. Return a pointer to the character after | |
394 | * the last byte written. | |
395 | */ | |
396 | static int kgdb_ebin2mem(char *buf, char *mem, int count) | |
397 | { | |
398 | int err = 0; | |
399 | char c; | |
400 | ||
401 | while (count-- > 0) { | |
402 | c = *buf++; | |
403 | if (c == 0x7d) | |
404 | c = *buf++ ^ 0x20; | |
405 | ||
406 | err = probe_kernel_write(mem, &c, 1); | |
407 | if (err) | |
408 | break; | |
409 | ||
410 | mem++; | |
411 | } | |
412 | ||
413 | return err; | |
414 | } | |
415 | ||
416 | /* | |
417 | * Convert the hex array pointed to by buf into binary to be placed in mem. | |
418 | * Return a pointer to the character AFTER the last byte written. | |
419 | * May return an error. | |
420 | */ | |
421 | int kgdb_hex2mem(char *buf, char *mem, int count) | |
422 | { | |
423 | char *tmp_raw; | |
424 | char *tmp_hex; | |
425 | ||
426 | /* | |
427 | * We use the upper half of buf as an intermediate buffer for the | |
428 | * raw memory that is converted from hex. | |
429 | */ | |
430 | tmp_raw = buf + count * 2; | |
431 | ||
432 | tmp_hex = tmp_raw - 1; | |
433 | while (tmp_hex >= buf) { | |
434 | tmp_raw--; | |
435 | *tmp_raw = hex(*tmp_hex--); | |
436 | *tmp_raw |= hex(*tmp_hex--) << 4; | |
437 | } | |
438 | ||
439 | return probe_kernel_write(mem, tmp_raw, count); | |
440 | } | |
441 | ||
442 | /* | |
443 | * While we find nice hex chars, build a long_val. | |
444 | * Return number of chars processed. | |
445 | */ | |
688b744d | 446 | int kgdb_hex2long(char **ptr, unsigned long *long_val) |
dc7d5527 JW |
447 | { |
448 | int hex_val; | |
449 | int num = 0; | |
25fc9999 | 450 | int negate = 0; |
dc7d5527 JW |
451 | |
452 | *long_val = 0; | |
453 | ||
25fc9999 JW |
454 | if (**ptr == '-') { |
455 | negate = 1; | |
456 | (*ptr)++; | |
457 | } | |
dc7d5527 JW |
458 | while (**ptr) { |
459 | hex_val = hex(**ptr); | |
460 | if (hex_val < 0) | |
461 | break; | |
462 | ||
463 | *long_val = (*long_val << 4) | hex_val; | |
464 | num++; | |
465 | (*ptr)++; | |
466 | } | |
467 | ||
25fc9999 JW |
468 | if (negate) |
469 | *long_val = -*long_val; | |
470 | ||
dc7d5527 JW |
471 | return num; |
472 | } | |
473 | ||
474 | /* Write memory due to an 'M' or 'X' packet. */ | |
475 | static int write_mem_msg(int binary) | |
476 | { | |
477 | char *ptr = &remcom_in_buffer[1]; | |
478 | unsigned long addr; | |
479 | unsigned long length; | |
480 | int err; | |
481 | ||
482 | if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' && | |
483 | kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') { | |
484 | if (binary) | |
485 | err = kgdb_ebin2mem(ptr, (char *)addr, length); | |
486 | else | |
487 | err = kgdb_hex2mem(ptr, (char *)addr, length); | |
488 | if (err) | |
489 | return err; | |
490 | if (CACHE_FLUSH_IS_SAFE) | |
18d6522b | 491 | flush_icache_range(addr, addr + length); |
dc7d5527 JW |
492 | return 0; |
493 | } | |
494 | ||
495 | return -EINVAL; | |
496 | } | |
497 | ||
498 | static void error_packet(char *pkt, int error) | |
499 | { | |
500 | error = -error; | |
501 | pkt[0] = 'E'; | |
827e609b HH |
502 | pkt[1] = hex_asc[(error / 10)]; |
503 | pkt[2] = hex_asc[(error % 10)]; | |
dc7d5527 JW |
504 | pkt[3] = '\0'; |
505 | } | |
506 | ||
507 | /* | |
508 | * Thread ID accessors. We represent a flat TID space to GDB, where | |
509 | * the per CPU idle threads (which under Linux all have PID 0) are | |
510 | * remapped to negative TIDs. | |
511 | */ | |
512 | ||
513 | #define BUF_THREAD_ID_SIZE 16 | |
514 | ||
515 | static char *pack_threadid(char *pkt, unsigned char *id) | |
516 | { | |
517 | char *limit; | |
518 | ||
519 | limit = pkt + BUF_THREAD_ID_SIZE; | |
520 | while (pkt < limit) | |
521 | pkt = pack_hex_byte(pkt, *id++); | |
522 | ||
523 | return pkt; | |
524 | } | |
525 | ||
526 | static void int_to_threadref(unsigned char *id, int value) | |
527 | { | |
528 | unsigned char *scan; | |
529 | int i = 4; | |
530 | ||
531 | scan = (unsigned char *)id; | |
532 | while (i--) | |
533 | *scan++ = 0; | |
827e609b | 534 | put_unaligned_be32(value, scan); |
dc7d5527 JW |
535 | } |
536 | ||
537 | static struct task_struct *getthread(struct pt_regs *regs, int tid) | |
538 | { | |
539 | /* | |
25fc9999 | 540 | * Non-positive TIDs are remapped to the cpu shadow information |
dc7d5527 | 541 | */ |
25fc9999 JW |
542 | if (tid == 0 || tid == -1) |
543 | tid = -atomic_read(&kgdb_active) - 2; | |
84667d48 | 544 | if (tid < -1 && tid > -NR_CPUS - 2) { |
25fc9999 JW |
545 | if (kgdb_info[-tid - 2].task) |
546 | return kgdb_info[-tid - 2].task; | |
547 | else | |
548 | return idle_task(-tid - 2); | |
549 | } | |
84667d48 JW |
550 | if (tid <= 0) { |
551 | printk(KERN_ERR "KGDB: Internal thread select error\n"); | |
552 | dump_stack(); | |
553 | return NULL; | |
554 | } | |
dc7d5527 JW |
555 | |
556 | /* | |
557 | * find_task_by_pid_ns() does not take the tasklist lock anymore | |
558 | * but is nicely RCU locked - hence is a pretty resilient | |
559 | * thing to use: | |
560 | */ | |
561 | return find_task_by_pid_ns(tid, &init_pid_ns); | |
562 | } | |
563 | ||
564 | /* | |
565 | * CPU debug state control: | |
566 | */ | |
567 | ||
568 | #ifdef CONFIG_SMP | |
569 | static void kgdb_wait(struct pt_regs *regs) | |
570 | { | |
571 | unsigned long flags; | |
572 | int cpu; | |
573 | ||
574 | local_irq_save(flags); | |
575 | cpu = raw_smp_processor_id(); | |
576 | kgdb_info[cpu].debuggerinfo = regs; | |
577 | kgdb_info[cpu].task = current; | |
578 | /* | |
579 | * Make sure the above info reaches the primary CPU before | |
580 | * our cpu_in_kgdb[] flag setting does: | |
581 | */ | |
582 | smp_wmb(); | |
583 | atomic_set(&cpu_in_kgdb[cpu], 1); | |
584 | ||
dc7d5527 JW |
585 | /* Wait till primary CPU is done with debugging */ |
586 | while (atomic_read(&passive_cpu_wait[cpu])) | |
587 | cpu_relax(); | |
588 | ||
589 | kgdb_info[cpu].debuggerinfo = NULL; | |
590 | kgdb_info[cpu].task = NULL; | |
591 | ||
592 | /* fix up hardware debug registers on local cpu */ | |
593 | if (arch_kgdb_ops.correct_hw_break) | |
594 | arch_kgdb_ops.correct_hw_break(); | |
595 | ||
596 | /* Signal the primary CPU that we are done: */ | |
597 | atomic_set(&cpu_in_kgdb[cpu], 0); | |
cc1e0f4f | 598 | touch_softlockup_watchdog(); |
7c3078b6 | 599 | clocksource_touch_watchdog(); |
dc7d5527 JW |
600 | local_irq_restore(flags); |
601 | } | |
602 | #endif | |
603 | ||
604 | /* | |
605 | * Some architectures need cache flushes when we set/clear a | |
606 | * breakpoint: | |
607 | */ | |
608 | static void kgdb_flush_swbreak_addr(unsigned long addr) | |
609 | { | |
610 | if (!CACHE_FLUSH_IS_SAFE) | |
611 | return; | |
612 | ||
737a460f | 613 | if (current->mm && current->mm->mmap_cache) { |
dc7d5527 JW |
614 | flush_cache_range(current->mm->mmap_cache, |
615 | addr, addr + BREAK_INSTR_SIZE); | |
dc7d5527 | 616 | } |
1a9a3e76 JW |
617 | /* Force flush instruction cache if it was outside the mm */ |
618 | flush_icache_range(addr, addr + BREAK_INSTR_SIZE); | |
dc7d5527 JW |
619 | } |
620 | ||
621 | /* | |
622 | * SW breakpoint management: | |
623 | */ | |
624 | static int kgdb_activate_sw_breakpoints(void) | |
625 | { | |
626 | unsigned long addr; | |
627 | int error = 0; | |
628 | int i; | |
629 | ||
630 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
631 | if (kgdb_break[i].state != BP_SET) | |
632 | continue; | |
633 | ||
634 | addr = kgdb_break[i].bpt_addr; | |
635 | error = kgdb_arch_set_breakpoint(addr, | |
636 | kgdb_break[i].saved_instr); | |
637 | if (error) | |
638 | return error; | |
639 | ||
640 | kgdb_flush_swbreak_addr(addr); | |
641 | kgdb_break[i].state = BP_ACTIVE; | |
642 | } | |
643 | return 0; | |
644 | } | |
645 | ||
646 | static int kgdb_set_sw_break(unsigned long addr) | |
647 | { | |
648 | int err = kgdb_validate_break_address(addr); | |
649 | int breakno = -1; | |
650 | int i; | |
651 | ||
652 | if (err) | |
653 | return err; | |
654 | ||
655 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
656 | if ((kgdb_break[i].state == BP_SET) && | |
657 | (kgdb_break[i].bpt_addr == addr)) | |
658 | return -EEXIST; | |
659 | } | |
660 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
661 | if (kgdb_break[i].state == BP_REMOVED && | |
662 | kgdb_break[i].bpt_addr == addr) { | |
663 | breakno = i; | |
664 | break; | |
665 | } | |
666 | } | |
667 | ||
668 | if (breakno == -1) { | |
669 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
670 | if (kgdb_break[i].state == BP_UNDEFINED) { | |
671 | breakno = i; | |
672 | break; | |
673 | } | |
674 | } | |
675 | } | |
676 | ||
677 | if (breakno == -1) | |
678 | return -E2BIG; | |
679 | ||
680 | kgdb_break[breakno].state = BP_SET; | |
681 | kgdb_break[breakno].type = BP_BREAKPOINT; | |
682 | kgdb_break[breakno].bpt_addr = addr; | |
683 | ||
684 | return 0; | |
685 | } | |
686 | ||
687 | static int kgdb_deactivate_sw_breakpoints(void) | |
688 | { | |
689 | unsigned long addr; | |
690 | int error = 0; | |
691 | int i; | |
692 | ||
693 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
694 | if (kgdb_break[i].state != BP_ACTIVE) | |
695 | continue; | |
696 | addr = kgdb_break[i].bpt_addr; | |
697 | error = kgdb_arch_remove_breakpoint(addr, | |
698 | kgdb_break[i].saved_instr); | |
699 | if (error) | |
700 | return error; | |
701 | ||
702 | kgdb_flush_swbreak_addr(addr); | |
703 | kgdb_break[i].state = BP_SET; | |
704 | } | |
705 | return 0; | |
706 | } | |
707 | ||
708 | static int kgdb_remove_sw_break(unsigned long addr) | |
709 | { | |
710 | int i; | |
711 | ||
712 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
713 | if ((kgdb_break[i].state == BP_SET) && | |
714 | (kgdb_break[i].bpt_addr == addr)) { | |
715 | kgdb_break[i].state = BP_REMOVED; | |
716 | return 0; | |
717 | } | |
718 | } | |
719 | return -ENOENT; | |
720 | } | |
721 | ||
722 | int kgdb_isremovedbreak(unsigned long addr) | |
723 | { | |
724 | int i; | |
725 | ||
726 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
727 | if ((kgdb_break[i].state == BP_REMOVED) && | |
728 | (kgdb_break[i].bpt_addr == addr)) | |
729 | return 1; | |
730 | } | |
731 | return 0; | |
732 | } | |
733 | ||
688b744d | 734 | static int remove_all_break(void) |
dc7d5527 JW |
735 | { |
736 | unsigned long addr; | |
737 | int error; | |
738 | int i; | |
739 | ||
740 | /* Clear memory breakpoints. */ | |
741 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
737a460f JW |
742 | if (kgdb_break[i].state != BP_ACTIVE) |
743 | goto setundefined; | |
dc7d5527 JW |
744 | addr = kgdb_break[i].bpt_addr; |
745 | error = kgdb_arch_remove_breakpoint(addr, | |
746 | kgdb_break[i].saved_instr); | |
747 | if (error) | |
737a460f JW |
748 | printk(KERN_ERR "KGDB: breakpoint remove failed: %lx\n", |
749 | addr); | |
750 | setundefined: | |
751 | kgdb_break[i].state = BP_UNDEFINED; | |
dc7d5527 JW |
752 | } |
753 | ||
754 | /* Clear hardware breakpoints. */ | |
755 | if (arch_kgdb_ops.remove_all_hw_break) | |
756 | arch_kgdb_ops.remove_all_hw_break(); | |
757 | ||
758 | return 0; | |
759 | } | |
760 | ||
761 | /* | |
25fc9999 JW |
762 | * Remap normal tasks to their real PID, |
763 | * CPU shadow threads are mapped to -CPU - 2 | |
dc7d5527 JW |
764 | */ |
765 | static inline int shadow_pid(int realpid) | |
766 | { | |
767 | if (realpid) | |
768 | return realpid; | |
769 | ||
25fc9999 | 770 | return -raw_smp_processor_id() - 2; |
dc7d5527 JW |
771 | } |
772 | ||
773 | static char gdbmsgbuf[BUFMAX + 1]; | |
774 | ||
775 | static void kgdb_msg_write(const char *s, int len) | |
776 | { | |
777 | char *bufptr; | |
778 | int wcount; | |
779 | int i; | |
780 | ||
781 | /* 'O'utput */ | |
782 | gdbmsgbuf[0] = 'O'; | |
783 | ||
784 | /* Fill and send buffers... */ | |
785 | while (len > 0) { | |
786 | bufptr = gdbmsgbuf + 1; | |
787 | ||
788 | /* Calculate how many this time */ | |
789 | if ((len << 1) > (BUFMAX - 2)) | |
790 | wcount = (BUFMAX - 2) >> 1; | |
791 | else | |
792 | wcount = len; | |
793 | ||
794 | /* Pack in hex chars */ | |
795 | for (i = 0; i < wcount; i++) | |
796 | bufptr = pack_hex_byte(bufptr, s[i]); | |
797 | *bufptr = '\0'; | |
798 | ||
799 | /* Move up */ | |
800 | s += wcount; | |
801 | len -= wcount; | |
802 | ||
803 | /* Write packet */ | |
804 | put_packet(gdbmsgbuf); | |
805 | } | |
806 | } | |
807 | ||
808 | /* | |
809 | * Return true if there is a valid kgdb I/O module. Also if no | |
810 | * debugger is attached a message can be printed to the console about | |
811 | * waiting for the debugger to attach. | |
812 | * | |
813 | * The print_wait argument is only to be true when called from inside | |
814 | * the core kgdb_handle_exception, because it will wait for the | |
815 | * debugger to attach. | |
816 | */ | |
817 | static int kgdb_io_ready(int print_wait) | |
818 | { | |
819 | if (!kgdb_io_ops) | |
820 | return 0; | |
821 | if (kgdb_connected) | |
822 | return 1; | |
823 | if (atomic_read(&kgdb_setting_breakpoint)) | |
824 | return 1; | |
825 | if (print_wait) | |
826 | printk(KERN_CRIT "KGDB: Waiting for remote debugger\n"); | |
827 | return 1; | |
828 | } | |
829 | ||
830 | /* | |
831 | * All the functions that start with gdb_cmd are the various | |
832 | * operations to implement the handlers for the gdbserial protocol | |
833 | * where KGDB is communicating with an external debugger | |
834 | */ | |
835 | ||
836 | /* Handle the '?' status packets */ | |
837 | static void gdb_cmd_status(struct kgdb_state *ks) | |
838 | { | |
839 | /* | |
840 | * We know that this packet is only sent | |
841 | * during initial connect. So to be safe, | |
842 | * we clear out our breakpoints now in case | |
843 | * GDB is reconnecting. | |
844 | */ | |
845 | remove_all_break(); | |
846 | ||
847 | remcom_out_buffer[0] = 'S'; | |
848 | pack_hex_byte(&remcom_out_buffer[1], ks->signo); | |
849 | } | |
850 | ||
851 | /* Handle the 'g' get registers request */ | |
852 | static void gdb_cmd_getregs(struct kgdb_state *ks) | |
853 | { | |
854 | struct task_struct *thread; | |
855 | void *local_debuggerinfo; | |
856 | int i; | |
857 | ||
858 | thread = kgdb_usethread; | |
859 | if (!thread) { | |
860 | thread = kgdb_info[ks->cpu].task; | |
861 | local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo; | |
862 | } else { | |
863 | local_debuggerinfo = NULL; | |
25fc9999 | 864 | for_each_online_cpu(i) { |
dc7d5527 JW |
865 | /* |
866 | * Try to find the task on some other | |
867 | * or possibly this node if we do not | |
868 | * find the matching task then we try | |
869 | * to approximate the results. | |
870 | */ | |
871 | if (thread == kgdb_info[i].task) | |
872 | local_debuggerinfo = kgdb_info[i].debuggerinfo; | |
873 | } | |
874 | } | |
875 | ||
876 | /* | |
877 | * All threads that don't have debuggerinfo should be | |
1477b6a7 | 878 | * in schedule() sleeping, since all other CPUs |
dc7d5527 JW |
879 | * are in kgdb_wait, and thus have debuggerinfo. |
880 | */ | |
881 | if (local_debuggerinfo) { | |
882 | pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo); | |
883 | } else { | |
884 | /* | |
885 | * Pull stuff saved during switch_to; nothing | |
886 | * else is accessible (or even particularly | |
887 | * relevant). | |
888 | * | |
889 | * This should be enough for a stack trace. | |
890 | */ | |
891 | sleeping_thread_to_gdb_regs(gdb_regs, thread); | |
892 | } | |
893 | kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES); | |
894 | } | |
895 | ||
896 | /* Handle the 'G' set registers request */ | |
897 | static void gdb_cmd_setregs(struct kgdb_state *ks) | |
898 | { | |
899 | kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES); | |
900 | ||
901 | if (kgdb_usethread && kgdb_usethread != current) { | |
902 | error_packet(remcom_out_buffer, -EINVAL); | |
903 | } else { | |
904 | gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs); | |
905 | strcpy(remcom_out_buffer, "OK"); | |
906 | } | |
907 | } | |
908 | ||
909 | /* Handle the 'm' memory read bytes */ | |
910 | static void gdb_cmd_memread(struct kgdb_state *ks) | |
911 | { | |
912 | char *ptr = &remcom_in_buffer[1]; | |
913 | unsigned long length; | |
914 | unsigned long addr; | |
915 | int err; | |
916 | ||
917 | if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' && | |
918 | kgdb_hex2long(&ptr, &length) > 0) { | |
919 | err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length); | |
920 | if (err) | |
921 | error_packet(remcom_out_buffer, err); | |
922 | } else { | |
923 | error_packet(remcom_out_buffer, -EINVAL); | |
924 | } | |
925 | } | |
926 | ||
927 | /* Handle the 'M' memory write bytes */ | |
928 | static void gdb_cmd_memwrite(struct kgdb_state *ks) | |
929 | { | |
930 | int err = write_mem_msg(0); | |
931 | ||
932 | if (err) | |
933 | error_packet(remcom_out_buffer, err); | |
934 | else | |
935 | strcpy(remcom_out_buffer, "OK"); | |
936 | } | |
937 | ||
938 | /* Handle the 'X' memory binary write bytes */ | |
939 | static void gdb_cmd_binwrite(struct kgdb_state *ks) | |
940 | { | |
941 | int err = write_mem_msg(1); | |
942 | ||
943 | if (err) | |
944 | error_packet(remcom_out_buffer, err); | |
945 | else | |
946 | strcpy(remcom_out_buffer, "OK"); | |
947 | } | |
948 | ||
949 | /* Handle the 'D' or 'k', detach or kill packets */ | |
950 | static void gdb_cmd_detachkill(struct kgdb_state *ks) | |
951 | { | |
952 | int error; | |
953 | ||
954 | /* The detach case */ | |
955 | if (remcom_in_buffer[0] == 'D') { | |
956 | error = remove_all_break(); | |
957 | if (error < 0) { | |
958 | error_packet(remcom_out_buffer, error); | |
959 | } else { | |
960 | strcpy(remcom_out_buffer, "OK"); | |
961 | kgdb_connected = 0; | |
962 | } | |
963 | put_packet(remcom_out_buffer); | |
964 | } else { | |
965 | /* | |
966 | * Assume the kill case, with no exit code checking, | |
967 | * trying to force detach the debugger: | |
968 | */ | |
969 | remove_all_break(); | |
970 | kgdb_connected = 0; | |
971 | } | |
972 | } | |
973 | ||
974 | /* Handle the 'R' reboot packets */ | |
975 | static int gdb_cmd_reboot(struct kgdb_state *ks) | |
976 | { | |
977 | /* For now, only honor R0 */ | |
978 | if (strcmp(remcom_in_buffer, "R0") == 0) { | |
979 | printk(KERN_CRIT "Executing emergency reboot\n"); | |
980 | strcpy(remcom_out_buffer, "OK"); | |
981 | put_packet(remcom_out_buffer); | |
982 | ||
983 | /* | |
984 | * Execution should not return from | |
985 | * machine_emergency_restart() | |
986 | */ | |
987 | machine_emergency_restart(); | |
988 | kgdb_connected = 0; | |
989 | ||
990 | return 1; | |
991 | } | |
992 | return 0; | |
993 | } | |
994 | ||
995 | /* Handle the 'q' query packets */ | |
996 | static void gdb_cmd_query(struct kgdb_state *ks) | |
997 | { | |
25fc9999 JW |
998 | struct task_struct *g; |
999 | struct task_struct *p; | |
dc7d5527 JW |
1000 | unsigned char thref[8]; |
1001 | char *ptr; | |
1002 | int i; | |
25fc9999 JW |
1003 | int cpu; |
1004 | int finished = 0; | |
dc7d5527 JW |
1005 | |
1006 | switch (remcom_in_buffer[1]) { | |
1007 | case 's': | |
1008 | case 'f': | |
1009 | if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) { | |
1010 | error_packet(remcom_out_buffer, -EINVAL); | |
1011 | break; | |
1012 | } | |
1013 | ||
25fc9999 | 1014 | i = 0; |
dc7d5527 JW |
1015 | remcom_out_buffer[0] = 'm'; |
1016 | ptr = remcom_out_buffer + 1; | |
25fc9999 JW |
1017 | if (remcom_in_buffer[1] == 'f') { |
1018 | /* Each cpu is a shadow thread */ | |
1019 | for_each_online_cpu(cpu) { | |
1020 | ks->thr_query = 0; | |
1021 | int_to_threadref(thref, -cpu - 2); | |
dc7d5527 JW |
1022 | pack_threadid(ptr, thref); |
1023 | ptr += BUF_THREAD_ID_SIZE; | |
1024 | *(ptr++) = ','; | |
1025 | i++; | |
1026 | } | |
1027 | } | |
25fc9999 JW |
1028 | |
1029 | do_each_thread(g, p) { | |
1030 | if (i >= ks->thr_query && !finished) { | |
1031 | int_to_threadref(thref, p->pid); | |
1032 | pack_threadid(ptr, thref); | |
1033 | ptr += BUF_THREAD_ID_SIZE; | |
1034 | *(ptr++) = ','; | |
1035 | ks->thr_query++; | |
1036 | if (ks->thr_query % KGDB_MAX_THREAD_QUERY == 0) | |
1037 | finished = 1; | |
1038 | } | |
1039 | i++; | |
1040 | } while_each_thread(g, p); | |
1041 | ||
dc7d5527 JW |
1042 | *(--ptr) = '\0'; |
1043 | break; | |
1044 | ||
1045 | case 'C': | |
1046 | /* Current thread id */ | |
1047 | strcpy(remcom_out_buffer, "QC"); | |
1048 | ks->threadid = shadow_pid(current->pid); | |
1049 | int_to_threadref(thref, ks->threadid); | |
1050 | pack_threadid(remcom_out_buffer + 2, thref); | |
1051 | break; | |
1052 | case 'T': | |
1053 | if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) { | |
1054 | error_packet(remcom_out_buffer, -EINVAL); | |
1055 | break; | |
1056 | } | |
1057 | ks->threadid = 0; | |
1058 | ptr = remcom_in_buffer + 17; | |
1059 | kgdb_hex2long(&ptr, &ks->threadid); | |
1060 | if (!getthread(ks->linux_regs, ks->threadid)) { | |
1061 | error_packet(remcom_out_buffer, -EINVAL); | |
1062 | break; | |
1063 | } | |
25fc9999 | 1064 | if ((int)ks->threadid > 0) { |
dc7d5527 JW |
1065 | kgdb_mem2hex(getthread(ks->linux_regs, |
1066 | ks->threadid)->comm, | |
1067 | remcom_out_buffer, 16); | |
1068 | } else { | |
1069 | static char tmpstr[23 + BUF_THREAD_ID_SIZE]; | |
1070 | ||
25fc9999 JW |
1071 | sprintf(tmpstr, "shadowCPU%d", |
1072 | (int)(-ks->threadid - 2)); | |
dc7d5527 JW |
1073 | kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr)); |
1074 | } | |
1075 | break; | |
1076 | } | |
1077 | } | |
1078 | ||
1079 | /* Handle the 'H' task query packets */ | |
1080 | static void gdb_cmd_task(struct kgdb_state *ks) | |
1081 | { | |
1082 | struct task_struct *thread; | |
1083 | char *ptr; | |
1084 | ||
1085 | switch (remcom_in_buffer[1]) { | |
1086 | case 'g': | |
1087 | ptr = &remcom_in_buffer[2]; | |
1088 | kgdb_hex2long(&ptr, &ks->threadid); | |
1089 | thread = getthread(ks->linux_regs, ks->threadid); | |
1090 | if (!thread && ks->threadid > 0) { | |
1091 | error_packet(remcom_out_buffer, -EINVAL); | |
1092 | break; | |
1093 | } | |
1094 | kgdb_usethread = thread; | |
1095 | ks->kgdb_usethreadid = ks->threadid; | |
1096 | strcpy(remcom_out_buffer, "OK"); | |
1097 | break; | |
1098 | case 'c': | |
1099 | ptr = &remcom_in_buffer[2]; | |
1100 | kgdb_hex2long(&ptr, &ks->threadid); | |
1101 | if (!ks->threadid) { | |
1102 | kgdb_contthread = NULL; | |
1103 | } else { | |
1104 | thread = getthread(ks->linux_regs, ks->threadid); | |
1105 | if (!thread && ks->threadid > 0) { | |
1106 | error_packet(remcom_out_buffer, -EINVAL); | |
1107 | break; | |
1108 | } | |
1109 | kgdb_contthread = thread; | |
1110 | } | |
1111 | strcpy(remcom_out_buffer, "OK"); | |
1112 | break; | |
1113 | } | |
1114 | } | |
1115 | ||
1116 | /* Handle the 'T' thread query packets */ | |
1117 | static void gdb_cmd_thread(struct kgdb_state *ks) | |
1118 | { | |
1119 | char *ptr = &remcom_in_buffer[1]; | |
1120 | struct task_struct *thread; | |
1121 | ||
1122 | kgdb_hex2long(&ptr, &ks->threadid); | |
1123 | thread = getthread(ks->linux_regs, ks->threadid); | |
1124 | if (thread) | |
1125 | strcpy(remcom_out_buffer, "OK"); | |
1126 | else | |
1127 | error_packet(remcom_out_buffer, -EINVAL); | |
1128 | } | |
1129 | ||
1130 | /* Handle the 'z' or 'Z' breakpoint remove or set packets */ | |
1131 | static void gdb_cmd_break(struct kgdb_state *ks) | |
1132 | { | |
1133 | /* | |
1134 | * Since GDB-5.3, it's been drafted that '0' is a software | |
1135 | * breakpoint, '1' is a hardware breakpoint, so let's do that. | |
1136 | */ | |
1137 | char *bpt_type = &remcom_in_buffer[1]; | |
1138 | char *ptr = &remcom_in_buffer[2]; | |
1139 | unsigned long addr; | |
1140 | unsigned long length; | |
1141 | int error = 0; | |
1142 | ||
1143 | if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') { | |
1144 | /* Unsupported */ | |
1145 | if (*bpt_type > '4') | |
1146 | return; | |
1147 | } else { | |
1148 | if (*bpt_type != '0' && *bpt_type != '1') | |
1149 | /* Unsupported. */ | |
1150 | return; | |
1151 | } | |
1152 | ||
1153 | /* | |
1154 | * Test if this is a hardware breakpoint, and | |
1155 | * if we support it: | |
1156 | */ | |
1157 | if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT)) | |
1158 | /* Unsupported. */ | |
1159 | return; | |
1160 | ||
1161 | if (*(ptr++) != ',') { | |
1162 | error_packet(remcom_out_buffer, -EINVAL); | |
1163 | return; | |
1164 | } | |
1165 | if (!kgdb_hex2long(&ptr, &addr)) { | |
1166 | error_packet(remcom_out_buffer, -EINVAL); | |
1167 | return; | |
1168 | } | |
1169 | if (*(ptr++) != ',' || | |
1170 | !kgdb_hex2long(&ptr, &length)) { | |
1171 | error_packet(remcom_out_buffer, -EINVAL); | |
1172 | return; | |
1173 | } | |
1174 | ||
1175 | if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0') | |
1176 | error = kgdb_set_sw_break(addr); | |
1177 | else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0') | |
1178 | error = kgdb_remove_sw_break(addr); | |
1179 | else if (remcom_in_buffer[0] == 'Z') | |
1180 | error = arch_kgdb_ops.set_hw_breakpoint(addr, | |
64e9ee30 | 1181 | (int)length, *bpt_type - '0'); |
dc7d5527 JW |
1182 | else if (remcom_in_buffer[0] == 'z') |
1183 | error = arch_kgdb_ops.remove_hw_breakpoint(addr, | |
64e9ee30 | 1184 | (int) length, *bpt_type - '0'); |
dc7d5527 JW |
1185 | |
1186 | if (error == 0) | |
1187 | strcpy(remcom_out_buffer, "OK"); | |
1188 | else | |
1189 | error_packet(remcom_out_buffer, error); | |
1190 | } | |
1191 | ||
1192 | /* Handle the 'C' signal / exception passing packets */ | |
1193 | static int gdb_cmd_exception_pass(struct kgdb_state *ks) | |
1194 | { | |
1195 | /* C09 == pass exception | |
1196 | * C15 == detach kgdb, pass exception | |
1197 | */ | |
1198 | if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') { | |
1199 | ||
1200 | ks->pass_exception = 1; | |
1201 | remcom_in_buffer[0] = 'c'; | |
1202 | ||
1203 | } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') { | |
1204 | ||
1205 | ks->pass_exception = 1; | |
1206 | remcom_in_buffer[0] = 'D'; | |
1207 | remove_all_break(); | |
1208 | kgdb_connected = 0; | |
1209 | return 1; | |
1210 | ||
1211 | } else { | |
1212 | error_packet(remcom_out_buffer, -EINVAL); | |
1213 | return 0; | |
1214 | } | |
1215 | ||
1216 | /* Indicate fall through */ | |
1217 | return -1; | |
1218 | } | |
1219 | ||
1220 | /* | |
1221 | * This function performs all gdbserial command procesing | |
1222 | */ | |
1223 | static int gdb_serial_stub(struct kgdb_state *ks) | |
1224 | { | |
1225 | int error = 0; | |
1226 | int tmp; | |
1227 | ||
1228 | /* Clear the out buffer. */ | |
1229 | memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); | |
1230 | ||
1231 | if (kgdb_connected) { | |
1232 | unsigned char thref[8]; | |
1233 | char *ptr; | |
1234 | ||
1235 | /* Reply to host that an exception has occurred */ | |
1236 | ptr = remcom_out_buffer; | |
1237 | *ptr++ = 'T'; | |
1238 | ptr = pack_hex_byte(ptr, ks->signo); | |
1239 | ptr += strlen(strcpy(ptr, "thread:")); | |
1240 | int_to_threadref(thref, shadow_pid(current->pid)); | |
1241 | ptr = pack_threadid(ptr, thref); | |
1242 | *ptr++ = ';'; | |
1243 | put_packet(remcom_out_buffer); | |
1244 | } | |
1245 | ||
1246 | kgdb_usethread = kgdb_info[ks->cpu].task; | |
1247 | ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid); | |
1248 | ks->pass_exception = 0; | |
1249 | ||
1250 | while (1) { | |
1251 | error = 0; | |
1252 | ||
1253 | /* Clear the out buffer. */ | |
1254 | memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); | |
1255 | ||
1256 | get_packet(remcom_in_buffer); | |
1257 | ||
1258 | switch (remcom_in_buffer[0]) { | |
1259 | case '?': /* gdbserial status */ | |
1260 | gdb_cmd_status(ks); | |
1261 | break; | |
1262 | case 'g': /* return the value of the CPU registers */ | |
1263 | gdb_cmd_getregs(ks); | |
1264 | break; | |
1265 | case 'G': /* set the value of the CPU registers - return OK */ | |
1266 | gdb_cmd_setregs(ks); | |
1267 | break; | |
1268 | case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ | |
1269 | gdb_cmd_memread(ks); | |
1270 | break; | |
1271 | case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */ | |
1272 | gdb_cmd_memwrite(ks); | |
1273 | break; | |
1274 | case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */ | |
1275 | gdb_cmd_binwrite(ks); | |
1276 | break; | |
1277 | /* kill or detach. KGDB should treat this like a | |
1278 | * continue. | |
1279 | */ | |
1280 | case 'D': /* Debugger detach */ | |
1281 | case 'k': /* Debugger detach via kill */ | |
1282 | gdb_cmd_detachkill(ks); | |
1283 | goto default_handle; | |
1284 | case 'R': /* Reboot */ | |
1285 | if (gdb_cmd_reboot(ks)) | |
1286 | goto default_handle; | |
1287 | break; | |
1288 | case 'q': /* query command */ | |
1289 | gdb_cmd_query(ks); | |
1290 | break; | |
1291 | case 'H': /* task related */ | |
1292 | gdb_cmd_task(ks); | |
1293 | break; | |
1294 | case 'T': /* Query thread status */ | |
1295 | gdb_cmd_thread(ks); | |
1296 | break; | |
1297 | case 'z': /* Break point remove */ | |
1298 | case 'Z': /* Break point set */ | |
1299 | gdb_cmd_break(ks); | |
1300 | break; | |
1301 | case 'C': /* Exception passing */ | |
1302 | tmp = gdb_cmd_exception_pass(ks); | |
1303 | if (tmp > 0) | |
1304 | goto default_handle; | |
1305 | if (tmp == 0) | |
1306 | break; | |
1307 | /* Fall through on tmp < 0 */ | |
1308 | case 'c': /* Continue packet */ | |
1309 | case 's': /* Single step packet */ | |
1310 | if (kgdb_contthread && kgdb_contthread != current) { | |
1311 | /* Can't switch threads in kgdb */ | |
1312 | error_packet(remcom_out_buffer, -EINVAL); | |
1313 | break; | |
1314 | } | |
1315 | kgdb_activate_sw_breakpoints(); | |
1316 | /* Fall through to default processing */ | |
1317 | default: | |
1318 | default_handle: | |
1319 | error = kgdb_arch_handle_exception(ks->ex_vector, | |
1320 | ks->signo, | |
1321 | ks->err_code, | |
1322 | remcom_in_buffer, | |
1323 | remcom_out_buffer, | |
1324 | ks->linux_regs); | |
1325 | /* | |
1326 | * Leave cmd processing on error, detach, | |
1327 | * kill, continue, or single step. | |
1328 | */ | |
1329 | if (error >= 0 || remcom_in_buffer[0] == 'D' || | |
1330 | remcom_in_buffer[0] == 'k') { | |
1331 | error = 0; | |
1332 | goto kgdb_exit; | |
1333 | } | |
1334 | ||
1335 | } | |
1336 | ||
1337 | /* reply to the request */ | |
1338 | put_packet(remcom_out_buffer); | |
1339 | } | |
1340 | ||
1341 | kgdb_exit: | |
1342 | if (ks->pass_exception) | |
1343 | error = 1; | |
1344 | return error; | |
1345 | } | |
1346 | ||
1347 | static int kgdb_reenter_check(struct kgdb_state *ks) | |
1348 | { | |
1349 | unsigned long addr; | |
1350 | ||
1351 | if (atomic_read(&kgdb_active) != raw_smp_processor_id()) | |
1352 | return 0; | |
1353 | ||
1354 | /* Panic on recursive debugger calls: */ | |
1355 | exception_level++; | |
1356 | addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs); | |
1357 | kgdb_deactivate_sw_breakpoints(); | |
1358 | ||
1359 | /* | |
1360 | * If the break point removed ok at the place exception | |
1361 | * occurred, try to recover and print a warning to the end | |
1362 | * user because the user planted a breakpoint in a place that | |
1363 | * KGDB needs in order to function. | |
1364 | */ | |
1365 | if (kgdb_remove_sw_break(addr) == 0) { | |
1366 | exception_level = 0; | |
1367 | kgdb_skipexception(ks->ex_vector, ks->linux_regs); | |
1368 | kgdb_activate_sw_breakpoints(); | |
67baf94c JW |
1369 | printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed %lx\n", |
1370 | addr); | |
dc7d5527 JW |
1371 | WARN_ON_ONCE(1); |
1372 | ||
1373 | return 1; | |
1374 | } | |
1375 | remove_all_break(); | |
1376 | kgdb_skipexception(ks->ex_vector, ks->linux_regs); | |
1377 | ||
1378 | if (exception_level > 1) { | |
1379 | dump_stack(); | |
1380 | panic("Recursive entry to debugger"); | |
1381 | } | |
1382 | ||
1383 | printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n"); | |
1384 | dump_stack(); | |
1385 | panic("Recursive entry to debugger"); | |
1386 | ||
1387 | return 1; | |
1388 | } | |
1389 | ||
1390 | /* | |
1391 | * kgdb_handle_exception() - main entry point from a kernel exception | |
1392 | * | |
1393 | * Locking hierarchy: | |
1394 | * interface locks, if any (begin_session) | |
1395 | * kgdb lock (kgdb_active) | |
1396 | */ | |
1397 | int | |
1398 | kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) | |
1399 | { | |
1400 | struct kgdb_state kgdb_var; | |
1401 | struct kgdb_state *ks = &kgdb_var; | |
1402 | unsigned long flags; | |
1403 | int error = 0; | |
1404 | int i, cpu; | |
1405 | ||
1406 | ks->cpu = raw_smp_processor_id(); | |
1407 | ks->ex_vector = evector; | |
1408 | ks->signo = signo; | |
1409 | ks->ex_vector = evector; | |
1410 | ks->err_code = ecode; | |
1411 | ks->kgdb_usethreadid = 0; | |
1412 | ks->linux_regs = regs; | |
1413 | ||
1414 | if (kgdb_reenter_check(ks)) | |
1415 | return 0; /* Ouch, double exception ! */ | |
1416 | ||
1417 | acquirelock: | |
1418 | /* | |
1419 | * Interrupts will be restored by the 'trap return' code, except when | |
1420 | * single stepping. | |
1421 | */ | |
1422 | local_irq_save(flags); | |
1423 | ||
1424 | cpu = raw_smp_processor_id(); | |
1425 | ||
1426 | /* | |
1427 | * Acquire the kgdb_active lock: | |
1428 | */ | |
1429 | while (atomic_cmpxchg(&kgdb_active, -1, cpu) != -1) | |
1430 | cpu_relax(); | |
1431 | ||
1432 | /* | |
1433 | * Do not start the debugger connection on this CPU if the last | |
1434 | * instance of the exception handler wanted to come into the | |
1435 | * debugger on a different CPU via a single step | |
1436 | */ | |
1437 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1 && | |
1438 | atomic_read(&kgdb_cpu_doing_single_step) != cpu) { | |
1439 | ||
1440 | atomic_set(&kgdb_active, -1); | |
cc1e0f4f | 1441 | touch_softlockup_watchdog(); |
7c3078b6 | 1442 | clocksource_touch_watchdog(); |
dc7d5527 JW |
1443 | local_irq_restore(flags); |
1444 | ||
1445 | goto acquirelock; | |
1446 | } | |
1447 | ||
1448 | if (!kgdb_io_ready(1)) { | |
1449 | error = 1; | |
1450 | goto kgdb_restore; /* No I/O connection, so resume the system */ | |
1451 | } | |
1452 | ||
1453 | /* | |
1454 | * Don't enter if we have hit a removed breakpoint. | |
1455 | */ | |
1456 | if (kgdb_skipexception(ks->ex_vector, ks->linux_regs)) | |
1457 | goto kgdb_restore; | |
1458 | ||
1459 | /* Call the I/O driver's pre_exception routine */ | |
1460 | if (kgdb_io_ops->pre_exception) | |
1461 | kgdb_io_ops->pre_exception(); | |
1462 | ||
1463 | kgdb_info[ks->cpu].debuggerinfo = ks->linux_regs; | |
1464 | kgdb_info[ks->cpu].task = current; | |
1465 | ||
1466 | kgdb_disable_hw_debug(ks->linux_regs); | |
1467 | ||
1468 | /* | |
1469 | * Get the passive CPU lock which will hold all the non-primary | |
1470 | * CPU in a spin state while the debugger is active | |
1471 | */ | |
d7161a65 | 1472 | if (!kgdb_single_step) { |
dc7d5527 JW |
1473 | for (i = 0; i < NR_CPUS; i++) |
1474 | atomic_set(&passive_cpu_wait[i], 1); | |
1475 | } | |
1476 | ||
dc7d5527 JW |
1477 | /* |
1478 | * spin_lock code is good enough as a barrier so we don't | |
1479 | * need one here: | |
1480 | */ | |
1481 | atomic_set(&cpu_in_kgdb[ks->cpu], 1); | |
1482 | ||
56fb7093 JW |
1483 | #ifdef CONFIG_SMP |
1484 | /* Signal the other CPUs to enter kgdb_wait() */ | |
d7161a65 | 1485 | if ((!kgdb_single_step) && kgdb_do_roundup) |
56fb7093 JW |
1486 | kgdb_roundup_cpus(flags); |
1487 | #endif | |
1488 | ||
dc7d5527 JW |
1489 | /* |
1490 | * Wait for the other CPUs to be notified and be waiting for us: | |
1491 | */ | |
1492 | for_each_online_cpu(i) { | |
1493 | while (!atomic_read(&cpu_in_kgdb[i])) | |
1494 | cpu_relax(); | |
1495 | } | |
1496 | ||
1497 | /* | |
1498 | * At this point the primary processor is completely | |
1499 | * in the debugger and all secondary CPUs are quiescent | |
1500 | */ | |
1501 | kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code); | |
1502 | kgdb_deactivate_sw_breakpoints(); | |
1503 | kgdb_single_step = 0; | |
d7161a65 | 1504 | kgdb_contthread = current; |
dc7d5527 JW |
1505 | exception_level = 0; |
1506 | ||
1507 | /* Talk to debugger with gdbserial protocol */ | |
1508 | error = gdb_serial_stub(ks); | |
1509 | ||
1510 | /* Call the I/O driver's post_exception routine */ | |
1511 | if (kgdb_io_ops->post_exception) | |
1512 | kgdb_io_ops->post_exception(); | |
1513 | ||
1514 | kgdb_info[ks->cpu].debuggerinfo = NULL; | |
1515 | kgdb_info[ks->cpu].task = NULL; | |
1516 | atomic_set(&cpu_in_kgdb[ks->cpu], 0); | |
1517 | ||
d7161a65 | 1518 | if (!kgdb_single_step) { |
dc7d5527 JW |
1519 | for (i = NR_CPUS-1; i >= 0; i--) |
1520 | atomic_set(&passive_cpu_wait[i], 0); | |
1521 | /* | |
1522 | * Wait till all the CPUs have quit | |
1523 | * from the debugger. | |
1524 | */ | |
1525 | for_each_online_cpu(i) { | |
1526 | while (atomic_read(&cpu_in_kgdb[i])) | |
1527 | cpu_relax(); | |
1528 | } | |
1529 | } | |
1530 | ||
1531 | kgdb_restore: | |
1532 | /* Free kgdb_active */ | |
1533 | atomic_set(&kgdb_active, -1); | |
cc1e0f4f | 1534 | touch_softlockup_watchdog(); |
7c3078b6 | 1535 | clocksource_touch_watchdog(); |
dc7d5527 JW |
1536 | local_irq_restore(flags); |
1537 | ||
1538 | return error; | |
1539 | } | |
1540 | ||
1541 | int kgdb_nmicallback(int cpu, void *regs) | |
1542 | { | |
1543 | #ifdef CONFIG_SMP | |
1544 | if (!atomic_read(&cpu_in_kgdb[cpu]) && | |
56fb7093 JW |
1545 | atomic_read(&kgdb_active) != cpu && |
1546 | atomic_read(&cpu_in_kgdb[atomic_read(&kgdb_active)])) { | |
dc7d5527 JW |
1547 | kgdb_wait((struct pt_regs *)regs); |
1548 | return 0; | |
1549 | } | |
1550 | #endif | |
1551 | return 1; | |
1552 | } | |
1553 | ||
aabdc3b8 JW |
1554 | static void kgdb_console_write(struct console *co, const char *s, |
1555 | unsigned count) | |
dc7d5527 JW |
1556 | { |
1557 | unsigned long flags; | |
1558 | ||
1559 | /* If we're debugging, or KGDB has not connected, don't try | |
1560 | * and print. */ | |
1561 | if (!kgdb_connected || atomic_read(&kgdb_active) != -1) | |
1562 | return; | |
1563 | ||
1564 | local_irq_save(flags); | |
1565 | kgdb_msg_write(s, count); | |
1566 | local_irq_restore(flags); | |
1567 | } | |
1568 | ||
1569 | static struct console kgdbcons = { | |
1570 | .name = "kgdb", | |
1571 | .write = kgdb_console_write, | |
1572 | .flags = CON_PRINTBUFFER | CON_ENABLED, | |
1573 | .index = -1, | |
1574 | }; | |
1575 | ||
1576 | #ifdef CONFIG_MAGIC_SYSRQ | |
1577 | static void sysrq_handle_gdb(int key, struct tty_struct *tty) | |
1578 | { | |
1579 | if (!kgdb_io_ops) { | |
1580 | printk(KERN_CRIT "ERROR: No KGDB I/O module available\n"); | |
1581 | return; | |
1582 | } | |
1583 | if (!kgdb_connected) | |
1584 | printk(KERN_CRIT "Entering KGDB\n"); | |
1585 | ||
1586 | kgdb_breakpoint(); | |
1587 | } | |
1588 | ||
1589 | static struct sysrq_key_op sysrq_gdb_op = { | |
1590 | .handler = sysrq_handle_gdb, | |
364b5b7b JW |
1591 | .help_msg = "debug(G)", |
1592 | .action_msg = "DEBUG", | |
dc7d5527 JW |
1593 | }; |
1594 | #endif | |
1595 | ||
1596 | static void kgdb_register_callbacks(void) | |
1597 | { | |
1598 | if (!kgdb_io_module_registered) { | |
1599 | kgdb_io_module_registered = 1; | |
1600 | kgdb_arch_init(); | |
1601 | #ifdef CONFIG_MAGIC_SYSRQ | |
1602 | register_sysrq_key('g', &sysrq_gdb_op); | |
1603 | #endif | |
1604 | if (kgdb_use_con && !kgdb_con_registered) { | |
1605 | register_console(&kgdbcons); | |
1606 | kgdb_con_registered = 1; | |
1607 | } | |
1608 | } | |
1609 | } | |
1610 | ||
1611 | static void kgdb_unregister_callbacks(void) | |
1612 | { | |
1613 | /* | |
1614 | * When this routine is called KGDB should unregister from the | |
1615 | * panic handler and clean up, making sure it is not handling any | |
1616 | * break exceptions at the time. | |
1617 | */ | |
1618 | if (kgdb_io_module_registered) { | |
1619 | kgdb_io_module_registered = 0; | |
1620 | kgdb_arch_exit(); | |
1621 | #ifdef CONFIG_MAGIC_SYSRQ | |
1622 | unregister_sysrq_key('g', &sysrq_gdb_op); | |
1623 | #endif | |
1624 | if (kgdb_con_registered) { | |
1625 | unregister_console(&kgdbcons); | |
1626 | kgdb_con_registered = 0; | |
1627 | } | |
1628 | } | |
1629 | } | |
1630 | ||
1631 | static void kgdb_initial_breakpoint(void) | |
1632 | { | |
1633 | kgdb_break_asap = 0; | |
1634 | ||
1635 | printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n"); | |
1636 | kgdb_breakpoint(); | |
1637 | } | |
1638 | ||
1639 | /** | |
737a460f | 1640 | * kgdb_register_io_module - register KGDB IO module |
dc7d5527 JW |
1641 | * @new_kgdb_io_ops: the io ops vector |
1642 | * | |
1643 | * Register it with the KGDB core. | |
1644 | */ | |
1645 | int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops) | |
1646 | { | |
1647 | int err; | |
1648 | ||
1649 | spin_lock(&kgdb_registration_lock); | |
1650 | ||
1651 | if (kgdb_io_ops) { | |
1652 | spin_unlock(&kgdb_registration_lock); | |
1653 | ||
1654 | printk(KERN_ERR "kgdb: Another I/O driver is already " | |
1655 | "registered with KGDB.\n"); | |
1656 | return -EBUSY; | |
1657 | } | |
1658 | ||
1659 | if (new_kgdb_io_ops->init) { | |
1660 | err = new_kgdb_io_ops->init(); | |
1661 | if (err) { | |
1662 | spin_unlock(&kgdb_registration_lock); | |
1663 | return err; | |
1664 | } | |
1665 | } | |
1666 | ||
1667 | kgdb_io_ops = new_kgdb_io_ops; | |
1668 | ||
1669 | spin_unlock(&kgdb_registration_lock); | |
1670 | ||
1671 | printk(KERN_INFO "kgdb: Registered I/O driver %s.\n", | |
1672 | new_kgdb_io_ops->name); | |
1673 | ||
1674 | /* Arm KGDB now. */ | |
1675 | kgdb_register_callbacks(); | |
1676 | ||
1677 | if (kgdb_break_asap) | |
1678 | kgdb_initial_breakpoint(); | |
1679 | ||
1680 | return 0; | |
1681 | } | |
1682 | EXPORT_SYMBOL_GPL(kgdb_register_io_module); | |
1683 | ||
1684 | /** | |
1685 | * kkgdb_unregister_io_module - unregister KGDB IO module | |
1686 | * @old_kgdb_io_ops: the io ops vector | |
1687 | * | |
1688 | * Unregister it with the KGDB core. | |
1689 | */ | |
1690 | void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops) | |
1691 | { | |
1692 | BUG_ON(kgdb_connected); | |
1693 | ||
1694 | /* | |
1695 | * KGDB is no longer able to communicate out, so | |
1696 | * unregister our callbacks and reset state. | |
1697 | */ | |
1698 | kgdb_unregister_callbacks(); | |
1699 | ||
1700 | spin_lock(&kgdb_registration_lock); | |
1701 | ||
1702 | WARN_ON_ONCE(kgdb_io_ops != old_kgdb_io_ops); | |
1703 | kgdb_io_ops = NULL; | |
1704 | ||
1705 | spin_unlock(&kgdb_registration_lock); | |
1706 | ||
1707 | printk(KERN_INFO | |
1708 | "kgdb: Unregistered I/O driver %s, debugger disabled.\n", | |
1709 | old_kgdb_io_ops->name); | |
1710 | } | |
1711 | EXPORT_SYMBOL_GPL(kgdb_unregister_io_module); | |
1712 | ||
1713 | /** | |
1714 | * kgdb_breakpoint - generate breakpoint exception | |
1715 | * | |
1716 | * This function will generate a breakpoint exception. It is used at the | |
1717 | * beginning of a program to sync up with a debugger and can be used | |
1718 | * otherwise as a quick means to stop program execution and "break" into | |
1719 | * the debugger. | |
1720 | */ | |
1721 | void kgdb_breakpoint(void) | |
1722 | { | |
1723 | atomic_set(&kgdb_setting_breakpoint, 1); | |
1724 | wmb(); /* Sync point before breakpoint */ | |
1725 | arch_kgdb_breakpoint(); | |
1726 | wmb(); /* Sync point after breakpoint */ | |
1727 | atomic_set(&kgdb_setting_breakpoint, 0); | |
1728 | } | |
1729 | EXPORT_SYMBOL_GPL(kgdb_breakpoint); | |
1730 | ||
1731 | static int __init opt_kgdb_wait(char *str) | |
1732 | { | |
1733 | kgdb_break_asap = 1; | |
1734 | ||
1735 | if (kgdb_io_module_registered) | |
1736 | kgdb_initial_breakpoint(); | |
1737 | ||
1738 | return 0; | |
1739 | } | |
1740 | ||
1741 | early_param("kgdbwait", opt_kgdb_wait); |