Commit | Line | Data |
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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> | |
55 | ||
56 | static int kgdb_break_asap; | |
57 | ||
58 | struct kgdb_state { | |
59 | int ex_vector; | |
60 | int signo; | |
61 | int err_code; | |
62 | int cpu; | |
63 | int pass_exception; | |
64 | long threadid; | |
65 | long kgdb_usethreadid; | |
66 | struct pt_regs *linux_regs; | |
67 | }; | |
68 | ||
69 | static struct debuggerinfo_struct { | |
70 | void *debuggerinfo; | |
71 | struct task_struct *task; | |
72 | } kgdb_info[NR_CPUS]; | |
73 | ||
74 | /** | |
75 | * kgdb_connected - Is a host GDB connected to us? | |
76 | */ | |
77 | int kgdb_connected; | |
78 | EXPORT_SYMBOL_GPL(kgdb_connected); | |
79 | ||
80 | /* All the KGDB handlers are installed */ | |
81 | static int kgdb_io_module_registered; | |
82 | ||
83 | /* Guard for recursive entry */ | |
84 | static int exception_level; | |
85 | ||
86 | static struct kgdb_io *kgdb_io_ops; | |
87 | static DEFINE_SPINLOCK(kgdb_registration_lock); | |
88 | ||
89 | /* kgdb console driver is loaded */ | |
90 | static int kgdb_con_registered; | |
91 | /* determine if kgdb console output should be used */ | |
92 | static int kgdb_use_con; | |
93 | ||
94 | static int __init opt_kgdb_con(char *str) | |
95 | { | |
96 | kgdb_use_con = 1; | |
97 | return 0; | |
98 | } | |
99 | ||
100 | early_param("kgdbcon", opt_kgdb_con); | |
101 | ||
102 | module_param(kgdb_use_con, int, 0644); | |
103 | ||
104 | /* | |
105 | * Holds information about breakpoints in a kernel. These breakpoints are | |
106 | * added and removed by gdb. | |
107 | */ | |
108 | static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = { | |
109 | [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED } | |
110 | }; | |
111 | ||
112 | /* | |
113 | * The CPU# of the active CPU, or -1 if none: | |
114 | */ | |
115 | atomic_t kgdb_active = ATOMIC_INIT(-1); | |
116 | ||
117 | /* | |
118 | * We use NR_CPUs not PERCPU, in case kgdb is used to debug early | |
119 | * bootup code (which might not have percpu set up yet): | |
120 | */ | |
121 | static atomic_t passive_cpu_wait[NR_CPUS]; | |
122 | static atomic_t cpu_in_kgdb[NR_CPUS]; | |
123 | atomic_t kgdb_setting_breakpoint; | |
124 | ||
125 | struct task_struct *kgdb_usethread; | |
126 | struct task_struct *kgdb_contthread; | |
127 | ||
128 | int kgdb_single_step; | |
129 | ||
130 | /* Our I/O buffers. */ | |
131 | static char remcom_in_buffer[BUFMAX]; | |
132 | static char remcom_out_buffer[BUFMAX]; | |
133 | ||
134 | /* Storage for the registers, in GDB format. */ | |
135 | static unsigned long gdb_regs[(NUMREGBYTES + | |
136 | sizeof(unsigned long) - 1) / | |
137 | sizeof(unsigned long)]; | |
138 | ||
139 | /* to keep track of the CPU which is doing the single stepping*/ | |
140 | atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1); | |
141 | ||
142 | /* | |
143 | * If you are debugging a problem where roundup (the collection of | |
144 | * all other CPUs) is a problem [this should be extremely rare], | |
145 | * then use the nokgdbroundup option to avoid roundup. In that case | |
146 | * the other CPUs might interfere with your debugging context, so | |
147 | * use this with care: | |
148 | */ | |
149 | int kgdb_do_roundup = 1; | |
150 | ||
151 | static int __init opt_nokgdbroundup(char *str) | |
152 | { | |
153 | kgdb_do_roundup = 0; | |
154 | ||
155 | return 0; | |
156 | } | |
157 | ||
158 | early_param("nokgdbroundup", opt_nokgdbroundup); | |
159 | ||
160 | /* | |
161 | * Finally, some KGDB code :-) | |
162 | */ | |
163 | ||
164 | /* | |
165 | * Weak aliases for breakpoint management, | |
166 | * can be overriden by architectures when needed: | |
167 | */ | |
168 | int __weak kgdb_validate_break_address(unsigned long addr) | |
169 | { | |
170 | char tmp_variable[BREAK_INSTR_SIZE]; | |
171 | ||
172 | return probe_kernel_read(tmp_variable, (char *)addr, BREAK_INSTR_SIZE); | |
173 | } | |
174 | ||
175 | int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr) | |
176 | { | |
177 | int err; | |
178 | ||
179 | err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE); | |
180 | if (err) | |
181 | return err; | |
182 | ||
183 | return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr, | |
184 | BREAK_INSTR_SIZE); | |
185 | } | |
186 | ||
187 | int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle) | |
188 | { | |
189 | return probe_kernel_write((char *)addr, | |
190 | (char *)bundle, BREAK_INSTR_SIZE); | |
191 | } | |
192 | ||
193 | unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs) | |
194 | { | |
195 | return instruction_pointer(regs); | |
196 | } | |
197 | ||
198 | int __weak kgdb_arch_init(void) | |
199 | { | |
200 | return 0; | |
201 | } | |
202 | ||
b4b8ac52 JW |
203 | int __weak kgdb_skipexception(int exception, struct pt_regs *regs) |
204 | { | |
205 | return 0; | |
206 | } | |
207 | ||
208 | void __weak | |
209 | kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code) | |
210 | { | |
211 | return; | |
212 | } | |
213 | ||
dc7d5527 JW |
214 | /** |
215 | * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb. | |
216 | * @regs: Current &struct pt_regs. | |
217 | * | |
218 | * This function will be called if the particular architecture must | |
219 | * disable hardware debugging while it is processing gdb packets or | |
220 | * handling exception. | |
221 | */ | |
222 | void __weak kgdb_disable_hw_debug(struct pt_regs *regs) | |
223 | { | |
224 | } | |
225 | ||
226 | /* | |
227 | * GDB remote protocol parser: | |
228 | */ | |
229 | ||
230 | static const char hexchars[] = "0123456789abcdef"; | |
231 | ||
232 | static int hex(char ch) | |
233 | { | |
234 | if ((ch >= 'a') && (ch <= 'f')) | |
235 | return ch - 'a' + 10; | |
236 | if ((ch >= '0') && (ch <= '9')) | |
237 | return ch - '0'; | |
238 | if ((ch >= 'A') && (ch <= 'F')) | |
239 | return ch - 'A' + 10; | |
240 | return -1; | |
241 | } | |
242 | ||
243 | /* scan for the sequence $<data>#<checksum> */ | |
244 | static void get_packet(char *buffer) | |
245 | { | |
246 | unsigned char checksum; | |
247 | unsigned char xmitcsum; | |
248 | int count; | |
249 | char ch; | |
250 | ||
251 | do { | |
252 | /* | |
253 | * Spin and wait around for the start character, ignore all | |
254 | * other characters: | |
255 | */ | |
256 | while ((ch = (kgdb_io_ops->read_char())) != '$') | |
257 | /* nothing */; | |
258 | ||
259 | kgdb_connected = 1; | |
260 | checksum = 0; | |
261 | xmitcsum = -1; | |
262 | ||
263 | count = 0; | |
264 | ||
265 | /* | |
266 | * now, read until a # or end of buffer is found: | |
267 | */ | |
268 | while (count < (BUFMAX - 1)) { | |
269 | ch = kgdb_io_ops->read_char(); | |
270 | if (ch == '#') | |
271 | break; | |
272 | checksum = checksum + ch; | |
273 | buffer[count] = ch; | |
274 | count = count + 1; | |
275 | } | |
276 | buffer[count] = 0; | |
277 | ||
278 | if (ch == '#') { | |
279 | xmitcsum = hex(kgdb_io_ops->read_char()) << 4; | |
280 | xmitcsum += hex(kgdb_io_ops->read_char()); | |
281 | ||
282 | if (checksum != xmitcsum) | |
283 | /* failed checksum */ | |
284 | kgdb_io_ops->write_char('-'); | |
285 | else | |
286 | /* successful transfer */ | |
287 | kgdb_io_ops->write_char('+'); | |
288 | if (kgdb_io_ops->flush) | |
289 | kgdb_io_ops->flush(); | |
290 | } | |
291 | } while (checksum != xmitcsum); | |
292 | } | |
293 | ||
294 | /* | |
295 | * Send the packet in buffer. | |
296 | * Check for gdb connection if asked for. | |
297 | */ | |
298 | static void put_packet(char *buffer) | |
299 | { | |
300 | unsigned char checksum; | |
301 | int count; | |
302 | char ch; | |
303 | ||
304 | /* | |
305 | * $<packet info>#<checksum>. | |
306 | */ | |
307 | while (1) { | |
308 | kgdb_io_ops->write_char('$'); | |
309 | checksum = 0; | |
310 | count = 0; | |
311 | ||
312 | while ((ch = buffer[count])) { | |
313 | kgdb_io_ops->write_char(ch); | |
314 | checksum += ch; | |
315 | count++; | |
316 | } | |
317 | ||
318 | kgdb_io_ops->write_char('#'); | |
319 | kgdb_io_ops->write_char(hexchars[checksum >> 4]); | |
320 | kgdb_io_ops->write_char(hexchars[checksum & 0xf]); | |
321 | if (kgdb_io_ops->flush) | |
322 | kgdb_io_ops->flush(); | |
323 | ||
324 | /* Now see what we get in reply. */ | |
325 | ch = kgdb_io_ops->read_char(); | |
326 | ||
327 | if (ch == 3) | |
328 | ch = kgdb_io_ops->read_char(); | |
329 | ||
330 | /* If we get an ACK, we are done. */ | |
331 | if (ch == '+') | |
332 | return; | |
333 | ||
334 | /* | |
335 | * If we get the start of another packet, this means | |
336 | * that GDB is attempting to reconnect. We will NAK | |
337 | * the packet being sent, and stop trying to send this | |
338 | * packet. | |
339 | */ | |
340 | if (ch == '$') { | |
341 | kgdb_io_ops->write_char('-'); | |
342 | if (kgdb_io_ops->flush) | |
343 | kgdb_io_ops->flush(); | |
344 | return; | |
345 | } | |
346 | } | |
347 | } | |
348 | ||
349 | static char *pack_hex_byte(char *pkt, u8 byte) | |
350 | { | |
351 | *pkt++ = hexchars[byte >> 4]; | |
352 | *pkt++ = hexchars[byte & 0xf]; | |
353 | ||
354 | return pkt; | |
355 | } | |
356 | ||
357 | /* | |
358 | * Convert the memory pointed to by mem into hex, placing result in buf. | |
359 | * Return a pointer to the last char put in buf (null). May return an error. | |
360 | */ | |
361 | int kgdb_mem2hex(char *mem, char *buf, int count) | |
362 | { | |
363 | char *tmp; | |
364 | int err; | |
365 | ||
366 | /* | |
367 | * We use the upper half of buf as an intermediate buffer for the | |
368 | * raw memory copy. Hex conversion will work against this one. | |
369 | */ | |
370 | tmp = buf + count; | |
371 | ||
372 | err = probe_kernel_read(tmp, mem, count); | |
373 | if (!err) { | |
374 | while (count > 0) { | |
375 | buf = pack_hex_byte(buf, *tmp); | |
376 | tmp++; | |
377 | count--; | |
378 | } | |
379 | ||
380 | *buf = 0; | |
381 | } | |
382 | ||
383 | return err; | |
384 | } | |
385 | ||
386 | /* | |
387 | * Copy the binary array pointed to by buf into mem. Fix $, #, and | |
388 | * 0x7d escaped with 0x7d. Return a pointer to the character after | |
389 | * the last byte written. | |
390 | */ | |
391 | static int kgdb_ebin2mem(char *buf, char *mem, int count) | |
392 | { | |
393 | int err = 0; | |
394 | char c; | |
395 | ||
396 | while (count-- > 0) { | |
397 | c = *buf++; | |
398 | if (c == 0x7d) | |
399 | c = *buf++ ^ 0x20; | |
400 | ||
401 | err = probe_kernel_write(mem, &c, 1); | |
402 | if (err) | |
403 | break; | |
404 | ||
405 | mem++; | |
406 | } | |
407 | ||
408 | return err; | |
409 | } | |
410 | ||
411 | /* | |
412 | * Convert the hex array pointed to by buf into binary to be placed in mem. | |
413 | * Return a pointer to the character AFTER the last byte written. | |
414 | * May return an error. | |
415 | */ | |
416 | int kgdb_hex2mem(char *buf, char *mem, int count) | |
417 | { | |
418 | char *tmp_raw; | |
419 | char *tmp_hex; | |
420 | ||
421 | /* | |
422 | * We use the upper half of buf as an intermediate buffer for the | |
423 | * raw memory that is converted from hex. | |
424 | */ | |
425 | tmp_raw = buf + count * 2; | |
426 | ||
427 | tmp_hex = tmp_raw - 1; | |
428 | while (tmp_hex >= buf) { | |
429 | tmp_raw--; | |
430 | *tmp_raw = hex(*tmp_hex--); | |
431 | *tmp_raw |= hex(*tmp_hex--) << 4; | |
432 | } | |
433 | ||
434 | return probe_kernel_write(mem, tmp_raw, count); | |
435 | } | |
436 | ||
437 | /* | |
438 | * While we find nice hex chars, build a long_val. | |
439 | * Return number of chars processed. | |
440 | */ | |
441 | int kgdb_hex2long(char **ptr, long *long_val) | |
442 | { | |
443 | int hex_val; | |
444 | int num = 0; | |
445 | ||
446 | *long_val = 0; | |
447 | ||
448 | while (**ptr) { | |
449 | hex_val = hex(**ptr); | |
450 | if (hex_val < 0) | |
451 | break; | |
452 | ||
453 | *long_val = (*long_val << 4) | hex_val; | |
454 | num++; | |
455 | (*ptr)++; | |
456 | } | |
457 | ||
458 | return num; | |
459 | } | |
460 | ||
461 | /* Write memory due to an 'M' or 'X' packet. */ | |
462 | static int write_mem_msg(int binary) | |
463 | { | |
464 | char *ptr = &remcom_in_buffer[1]; | |
465 | unsigned long addr; | |
466 | unsigned long length; | |
467 | int err; | |
468 | ||
469 | if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' && | |
470 | kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') { | |
471 | if (binary) | |
472 | err = kgdb_ebin2mem(ptr, (char *)addr, length); | |
473 | else | |
474 | err = kgdb_hex2mem(ptr, (char *)addr, length); | |
475 | if (err) | |
476 | return err; | |
477 | if (CACHE_FLUSH_IS_SAFE) | |
478 | flush_icache_range(addr, addr + length + 1); | |
479 | return 0; | |
480 | } | |
481 | ||
482 | return -EINVAL; | |
483 | } | |
484 | ||
485 | static void error_packet(char *pkt, int error) | |
486 | { | |
487 | error = -error; | |
488 | pkt[0] = 'E'; | |
489 | pkt[1] = hexchars[(error / 10)]; | |
490 | pkt[2] = hexchars[(error % 10)]; | |
491 | pkt[3] = '\0'; | |
492 | } | |
493 | ||
494 | /* | |
495 | * Thread ID accessors. We represent a flat TID space to GDB, where | |
496 | * the per CPU idle threads (which under Linux all have PID 0) are | |
497 | * remapped to negative TIDs. | |
498 | */ | |
499 | ||
500 | #define BUF_THREAD_ID_SIZE 16 | |
501 | ||
502 | static char *pack_threadid(char *pkt, unsigned char *id) | |
503 | { | |
504 | char *limit; | |
505 | ||
506 | limit = pkt + BUF_THREAD_ID_SIZE; | |
507 | while (pkt < limit) | |
508 | pkt = pack_hex_byte(pkt, *id++); | |
509 | ||
510 | return pkt; | |
511 | } | |
512 | ||
513 | static void int_to_threadref(unsigned char *id, int value) | |
514 | { | |
515 | unsigned char *scan; | |
516 | int i = 4; | |
517 | ||
518 | scan = (unsigned char *)id; | |
519 | while (i--) | |
520 | *scan++ = 0; | |
521 | *scan++ = (value >> 24) & 0xff; | |
522 | *scan++ = (value >> 16) & 0xff; | |
523 | *scan++ = (value >> 8) & 0xff; | |
524 | *scan++ = (value & 0xff); | |
525 | } | |
526 | ||
527 | static struct task_struct *getthread(struct pt_regs *regs, int tid) | |
528 | { | |
529 | /* | |
530 | * Non-positive TIDs are remapped idle tasks: | |
531 | */ | |
532 | if (tid <= 0) | |
533 | return idle_task(-tid); | |
534 | ||
535 | /* | |
536 | * find_task_by_pid_ns() does not take the tasklist lock anymore | |
537 | * but is nicely RCU locked - hence is a pretty resilient | |
538 | * thing to use: | |
539 | */ | |
540 | return find_task_by_pid_ns(tid, &init_pid_ns); | |
541 | } | |
542 | ||
543 | /* | |
544 | * CPU debug state control: | |
545 | */ | |
546 | ||
547 | #ifdef CONFIG_SMP | |
548 | static void kgdb_wait(struct pt_regs *regs) | |
549 | { | |
550 | unsigned long flags; | |
551 | int cpu; | |
552 | ||
553 | local_irq_save(flags); | |
554 | cpu = raw_smp_processor_id(); | |
555 | kgdb_info[cpu].debuggerinfo = regs; | |
556 | kgdb_info[cpu].task = current; | |
557 | /* | |
558 | * Make sure the above info reaches the primary CPU before | |
559 | * our cpu_in_kgdb[] flag setting does: | |
560 | */ | |
561 | smp_wmb(); | |
562 | atomic_set(&cpu_in_kgdb[cpu], 1); | |
563 | ||
564 | /* | |
565 | * The primary CPU must be active to enter here, but this is | |
566 | * guard in case the primary CPU had not been selected if | |
567 | * this was an entry via nmi. | |
568 | */ | |
569 | while (atomic_read(&kgdb_active) == -1) | |
570 | cpu_relax(); | |
571 | ||
572 | /* Wait till primary CPU goes completely into the debugger. */ | |
573 | while (!atomic_read(&cpu_in_kgdb[atomic_read(&kgdb_active)])) | |
574 | cpu_relax(); | |
575 | ||
576 | /* Wait till primary CPU is done with debugging */ | |
577 | while (atomic_read(&passive_cpu_wait[cpu])) | |
578 | cpu_relax(); | |
579 | ||
580 | kgdb_info[cpu].debuggerinfo = NULL; | |
581 | kgdb_info[cpu].task = NULL; | |
582 | ||
583 | /* fix up hardware debug registers on local cpu */ | |
584 | if (arch_kgdb_ops.correct_hw_break) | |
585 | arch_kgdb_ops.correct_hw_break(); | |
586 | ||
587 | /* Signal the primary CPU that we are done: */ | |
588 | atomic_set(&cpu_in_kgdb[cpu], 0); | |
7c3078b6 | 589 | clocksource_touch_watchdog(); |
dc7d5527 JW |
590 | local_irq_restore(flags); |
591 | } | |
592 | #endif | |
593 | ||
594 | /* | |
595 | * Some architectures need cache flushes when we set/clear a | |
596 | * breakpoint: | |
597 | */ | |
598 | static void kgdb_flush_swbreak_addr(unsigned long addr) | |
599 | { | |
600 | if (!CACHE_FLUSH_IS_SAFE) | |
601 | return; | |
602 | ||
603 | if (current->mm) { | |
604 | flush_cache_range(current->mm->mmap_cache, | |
605 | addr, addr + BREAK_INSTR_SIZE); | |
606 | } else { | |
607 | flush_icache_range(addr, addr + BREAK_INSTR_SIZE); | |
608 | } | |
609 | } | |
610 | ||
611 | /* | |
612 | * SW breakpoint management: | |
613 | */ | |
614 | static int kgdb_activate_sw_breakpoints(void) | |
615 | { | |
616 | unsigned long addr; | |
617 | int error = 0; | |
618 | int i; | |
619 | ||
620 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
621 | if (kgdb_break[i].state != BP_SET) | |
622 | continue; | |
623 | ||
624 | addr = kgdb_break[i].bpt_addr; | |
625 | error = kgdb_arch_set_breakpoint(addr, | |
626 | kgdb_break[i].saved_instr); | |
627 | if (error) | |
628 | return error; | |
629 | ||
630 | kgdb_flush_swbreak_addr(addr); | |
631 | kgdb_break[i].state = BP_ACTIVE; | |
632 | } | |
633 | return 0; | |
634 | } | |
635 | ||
636 | static int kgdb_set_sw_break(unsigned long addr) | |
637 | { | |
638 | int err = kgdb_validate_break_address(addr); | |
639 | int breakno = -1; | |
640 | int i; | |
641 | ||
642 | if (err) | |
643 | return err; | |
644 | ||
645 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
646 | if ((kgdb_break[i].state == BP_SET) && | |
647 | (kgdb_break[i].bpt_addr == addr)) | |
648 | return -EEXIST; | |
649 | } | |
650 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
651 | if (kgdb_break[i].state == BP_REMOVED && | |
652 | kgdb_break[i].bpt_addr == addr) { | |
653 | breakno = i; | |
654 | break; | |
655 | } | |
656 | } | |
657 | ||
658 | if (breakno == -1) { | |
659 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
660 | if (kgdb_break[i].state == BP_UNDEFINED) { | |
661 | breakno = i; | |
662 | break; | |
663 | } | |
664 | } | |
665 | } | |
666 | ||
667 | if (breakno == -1) | |
668 | return -E2BIG; | |
669 | ||
670 | kgdb_break[breakno].state = BP_SET; | |
671 | kgdb_break[breakno].type = BP_BREAKPOINT; | |
672 | kgdb_break[breakno].bpt_addr = addr; | |
673 | ||
674 | return 0; | |
675 | } | |
676 | ||
677 | static int kgdb_deactivate_sw_breakpoints(void) | |
678 | { | |
679 | unsigned long addr; | |
680 | int error = 0; | |
681 | int i; | |
682 | ||
683 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
684 | if (kgdb_break[i].state != BP_ACTIVE) | |
685 | continue; | |
686 | addr = kgdb_break[i].bpt_addr; | |
687 | error = kgdb_arch_remove_breakpoint(addr, | |
688 | kgdb_break[i].saved_instr); | |
689 | if (error) | |
690 | return error; | |
691 | ||
692 | kgdb_flush_swbreak_addr(addr); | |
693 | kgdb_break[i].state = BP_SET; | |
694 | } | |
695 | return 0; | |
696 | } | |
697 | ||
698 | static int kgdb_remove_sw_break(unsigned long addr) | |
699 | { | |
700 | int i; | |
701 | ||
702 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
703 | if ((kgdb_break[i].state == BP_SET) && | |
704 | (kgdb_break[i].bpt_addr == addr)) { | |
705 | kgdb_break[i].state = BP_REMOVED; | |
706 | return 0; | |
707 | } | |
708 | } | |
709 | return -ENOENT; | |
710 | } | |
711 | ||
712 | int kgdb_isremovedbreak(unsigned long addr) | |
713 | { | |
714 | int i; | |
715 | ||
716 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
717 | if ((kgdb_break[i].state == BP_REMOVED) && | |
718 | (kgdb_break[i].bpt_addr == addr)) | |
719 | return 1; | |
720 | } | |
721 | return 0; | |
722 | } | |
723 | ||
724 | int remove_all_break(void) | |
725 | { | |
726 | unsigned long addr; | |
727 | int error; | |
728 | int i; | |
729 | ||
730 | /* Clear memory breakpoints. */ | |
731 | for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { | |
732 | if (kgdb_break[i].state != BP_SET) | |
733 | continue; | |
734 | addr = kgdb_break[i].bpt_addr; | |
735 | error = kgdb_arch_remove_breakpoint(addr, | |
736 | kgdb_break[i].saved_instr); | |
737 | if (error) | |
738 | return error; | |
739 | kgdb_break[i].state = BP_REMOVED; | |
740 | } | |
741 | ||
742 | /* Clear hardware breakpoints. */ | |
743 | if (arch_kgdb_ops.remove_all_hw_break) | |
744 | arch_kgdb_ops.remove_all_hw_break(); | |
745 | ||
746 | return 0; | |
747 | } | |
748 | ||
749 | /* | |
750 | * Remap normal tasks to their real PID, idle tasks to -1 ... -NR_CPUs: | |
751 | */ | |
752 | static inline int shadow_pid(int realpid) | |
753 | { | |
754 | if (realpid) | |
755 | return realpid; | |
756 | ||
757 | return -1-raw_smp_processor_id(); | |
758 | } | |
759 | ||
760 | static char gdbmsgbuf[BUFMAX + 1]; | |
761 | ||
762 | static void kgdb_msg_write(const char *s, int len) | |
763 | { | |
764 | char *bufptr; | |
765 | int wcount; | |
766 | int i; | |
767 | ||
768 | /* 'O'utput */ | |
769 | gdbmsgbuf[0] = 'O'; | |
770 | ||
771 | /* Fill and send buffers... */ | |
772 | while (len > 0) { | |
773 | bufptr = gdbmsgbuf + 1; | |
774 | ||
775 | /* Calculate how many this time */ | |
776 | if ((len << 1) > (BUFMAX - 2)) | |
777 | wcount = (BUFMAX - 2) >> 1; | |
778 | else | |
779 | wcount = len; | |
780 | ||
781 | /* Pack in hex chars */ | |
782 | for (i = 0; i < wcount; i++) | |
783 | bufptr = pack_hex_byte(bufptr, s[i]); | |
784 | *bufptr = '\0'; | |
785 | ||
786 | /* Move up */ | |
787 | s += wcount; | |
788 | len -= wcount; | |
789 | ||
790 | /* Write packet */ | |
791 | put_packet(gdbmsgbuf); | |
792 | } | |
793 | } | |
794 | ||
795 | /* | |
796 | * Return true if there is a valid kgdb I/O module. Also if no | |
797 | * debugger is attached a message can be printed to the console about | |
798 | * waiting for the debugger to attach. | |
799 | * | |
800 | * The print_wait argument is only to be true when called from inside | |
801 | * the core kgdb_handle_exception, because it will wait for the | |
802 | * debugger to attach. | |
803 | */ | |
804 | static int kgdb_io_ready(int print_wait) | |
805 | { | |
806 | if (!kgdb_io_ops) | |
807 | return 0; | |
808 | if (kgdb_connected) | |
809 | return 1; | |
810 | if (atomic_read(&kgdb_setting_breakpoint)) | |
811 | return 1; | |
812 | if (print_wait) | |
813 | printk(KERN_CRIT "KGDB: Waiting for remote debugger\n"); | |
814 | return 1; | |
815 | } | |
816 | ||
817 | /* | |
818 | * All the functions that start with gdb_cmd are the various | |
819 | * operations to implement the handlers for the gdbserial protocol | |
820 | * where KGDB is communicating with an external debugger | |
821 | */ | |
822 | ||
823 | /* Handle the '?' status packets */ | |
824 | static void gdb_cmd_status(struct kgdb_state *ks) | |
825 | { | |
826 | /* | |
827 | * We know that this packet is only sent | |
828 | * during initial connect. So to be safe, | |
829 | * we clear out our breakpoints now in case | |
830 | * GDB is reconnecting. | |
831 | */ | |
832 | remove_all_break(); | |
833 | ||
834 | remcom_out_buffer[0] = 'S'; | |
835 | pack_hex_byte(&remcom_out_buffer[1], ks->signo); | |
836 | } | |
837 | ||
838 | /* Handle the 'g' get registers request */ | |
839 | static void gdb_cmd_getregs(struct kgdb_state *ks) | |
840 | { | |
841 | struct task_struct *thread; | |
842 | void *local_debuggerinfo; | |
843 | int i; | |
844 | ||
845 | thread = kgdb_usethread; | |
846 | if (!thread) { | |
847 | thread = kgdb_info[ks->cpu].task; | |
848 | local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo; | |
849 | } else { | |
850 | local_debuggerinfo = NULL; | |
851 | for (i = 0; i < NR_CPUS; i++) { | |
852 | /* | |
853 | * Try to find the task on some other | |
854 | * or possibly this node if we do not | |
855 | * find the matching task then we try | |
856 | * to approximate the results. | |
857 | */ | |
858 | if (thread == kgdb_info[i].task) | |
859 | local_debuggerinfo = kgdb_info[i].debuggerinfo; | |
860 | } | |
861 | } | |
862 | ||
863 | /* | |
864 | * All threads that don't have debuggerinfo should be | |
865 | * in __schedule() sleeping, since all other CPUs | |
866 | * are in kgdb_wait, and thus have debuggerinfo. | |
867 | */ | |
868 | if (local_debuggerinfo) { | |
869 | pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo); | |
870 | } else { | |
871 | /* | |
872 | * Pull stuff saved during switch_to; nothing | |
873 | * else is accessible (or even particularly | |
874 | * relevant). | |
875 | * | |
876 | * This should be enough for a stack trace. | |
877 | */ | |
878 | sleeping_thread_to_gdb_regs(gdb_regs, thread); | |
879 | } | |
880 | kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES); | |
881 | } | |
882 | ||
883 | /* Handle the 'G' set registers request */ | |
884 | static void gdb_cmd_setregs(struct kgdb_state *ks) | |
885 | { | |
886 | kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES); | |
887 | ||
888 | if (kgdb_usethread && kgdb_usethread != current) { | |
889 | error_packet(remcom_out_buffer, -EINVAL); | |
890 | } else { | |
891 | gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs); | |
892 | strcpy(remcom_out_buffer, "OK"); | |
893 | } | |
894 | } | |
895 | ||
896 | /* Handle the 'm' memory read bytes */ | |
897 | static void gdb_cmd_memread(struct kgdb_state *ks) | |
898 | { | |
899 | char *ptr = &remcom_in_buffer[1]; | |
900 | unsigned long length; | |
901 | unsigned long addr; | |
902 | int err; | |
903 | ||
904 | if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' && | |
905 | kgdb_hex2long(&ptr, &length) > 0) { | |
906 | err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length); | |
907 | if (err) | |
908 | error_packet(remcom_out_buffer, err); | |
909 | } else { | |
910 | error_packet(remcom_out_buffer, -EINVAL); | |
911 | } | |
912 | } | |
913 | ||
914 | /* Handle the 'M' memory write bytes */ | |
915 | static void gdb_cmd_memwrite(struct kgdb_state *ks) | |
916 | { | |
917 | int err = write_mem_msg(0); | |
918 | ||
919 | if (err) | |
920 | error_packet(remcom_out_buffer, err); | |
921 | else | |
922 | strcpy(remcom_out_buffer, "OK"); | |
923 | } | |
924 | ||
925 | /* Handle the 'X' memory binary write bytes */ | |
926 | static void gdb_cmd_binwrite(struct kgdb_state *ks) | |
927 | { | |
928 | int err = write_mem_msg(1); | |
929 | ||
930 | if (err) | |
931 | error_packet(remcom_out_buffer, err); | |
932 | else | |
933 | strcpy(remcom_out_buffer, "OK"); | |
934 | } | |
935 | ||
936 | /* Handle the 'D' or 'k', detach or kill packets */ | |
937 | static void gdb_cmd_detachkill(struct kgdb_state *ks) | |
938 | { | |
939 | int error; | |
940 | ||
941 | /* The detach case */ | |
942 | if (remcom_in_buffer[0] == 'D') { | |
943 | error = remove_all_break(); | |
944 | if (error < 0) { | |
945 | error_packet(remcom_out_buffer, error); | |
946 | } else { | |
947 | strcpy(remcom_out_buffer, "OK"); | |
948 | kgdb_connected = 0; | |
949 | } | |
950 | put_packet(remcom_out_buffer); | |
951 | } else { | |
952 | /* | |
953 | * Assume the kill case, with no exit code checking, | |
954 | * trying to force detach the debugger: | |
955 | */ | |
956 | remove_all_break(); | |
957 | kgdb_connected = 0; | |
958 | } | |
959 | } | |
960 | ||
961 | /* Handle the 'R' reboot packets */ | |
962 | static int gdb_cmd_reboot(struct kgdb_state *ks) | |
963 | { | |
964 | /* For now, only honor R0 */ | |
965 | if (strcmp(remcom_in_buffer, "R0") == 0) { | |
966 | printk(KERN_CRIT "Executing emergency reboot\n"); | |
967 | strcpy(remcom_out_buffer, "OK"); | |
968 | put_packet(remcom_out_buffer); | |
969 | ||
970 | /* | |
971 | * Execution should not return from | |
972 | * machine_emergency_restart() | |
973 | */ | |
974 | machine_emergency_restart(); | |
975 | kgdb_connected = 0; | |
976 | ||
977 | return 1; | |
978 | } | |
979 | return 0; | |
980 | } | |
981 | ||
982 | /* Handle the 'q' query packets */ | |
983 | static void gdb_cmd_query(struct kgdb_state *ks) | |
984 | { | |
985 | struct task_struct *thread; | |
986 | unsigned char thref[8]; | |
987 | char *ptr; | |
988 | int i; | |
989 | ||
990 | switch (remcom_in_buffer[1]) { | |
991 | case 's': | |
992 | case 'f': | |
993 | if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) { | |
994 | error_packet(remcom_out_buffer, -EINVAL); | |
995 | break; | |
996 | } | |
997 | ||
998 | if (remcom_in_buffer[1] == 'f') | |
999 | ks->threadid = 1; | |
1000 | ||
1001 | remcom_out_buffer[0] = 'm'; | |
1002 | ptr = remcom_out_buffer + 1; | |
1003 | ||
1004 | for (i = 0; i < 17; ks->threadid++) { | |
1005 | thread = getthread(ks->linux_regs, ks->threadid); | |
1006 | if (thread) { | |
1007 | int_to_threadref(thref, ks->threadid); | |
1008 | pack_threadid(ptr, thref); | |
1009 | ptr += BUF_THREAD_ID_SIZE; | |
1010 | *(ptr++) = ','; | |
1011 | i++; | |
1012 | } | |
1013 | } | |
1014 | *(--ptr) = '\0'; | |
1015 | break; | |
1016 | ||
1017 | case 'C': | |
1018 | /* Current thread id */ | |
1019 | strcpy(remcom_out_buffer, "QC"); | |
1020 | ks->threadid = shadow_pid(current->pid); | |
1021 | int_to_threadref(thref, ks->threadid); | |
1022 | pack_threadid(remcom_out_buffer + 2, thref); | |
1023 | break; | |
1024 | case 'T': | |
1025 | if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) { | |
1026 | error_packet(remcom_out_buffer, -EINVAL); | |
1027 | break; | |
1028 | } | |
1029 | ks->threadid = 0; | |
1030 | ptr = remcom_in_buffer + 17; | |
1031 | kgdb_hex2long(&ptr, &ks->threadid); | |
1032 | if (!getthread(ks->linux_regs, ks->threadid)) { | |
1033 | error_packet(remcom_out_buffer, -EINVAL); | |
1034 | break; | |
1035 | } | |
1036 | if (ks->threadid > 0) { | |
1037 | kgdb_mem2hex(getthread(ks->linux_regs, | |
1038 | ks->threadid)->comm, | |
1039 | remcom_out_buffer, 16); | |
1040 | } else { | |
1041 | static char tmpstr[23 + BUF_THREAD_ID_SIZE]; | |
1042 | ||
1043 | sprintf(tmpstr, "Shadow task %d for pid 0", | |
1044 | (int)(-ks->threadid-1)); | |
1045 | kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr)); | |
1046 | } | |
1047 | break; | |
1048 | } | |
1049 | } | |
1050 | ||
1051 | /* Handle the 'H' task query packets */ | |
1052 | static void gdb_cmd_task(struct kgdb_state *ks) | |
1053 | { | |
1054 | struct task_struct *thread; | |
1055 | char *ptr; | |
1056 | ||
1057 | switch (remcom_in_buffer[1]) { | |
1058 | case 'g': | |
1059 | ptr = &remcom_in_buffer[2]; | |
1060 | kgdb_hex2long(&ptr, &ks->threadid); | |
1061 | thread = getthread(ks->linux_regs, ks->threadid); | |
1062 | if (!thread && ks->threadid > 0) { | |
1063 | error_packet(remcom_out_buffer, -EINVAL); | |
1064 | break; | |
1065 | } | |
1066 | kgdb_usethread = thread; | |
1067 | ks->kgdb_usethreadid = ks->threadid; | |
1068 | strcpy(remcom_out_buffer, "OK"); | |
1069 | break; | |
1070 | case 'c': | |
1071 | ptr = &remcom_in_buffer[2]; | |
1072 | kgdb_hex2long(&ptr, &ks->threadid); | |
1073 | if (!ks->threadid) { | |
1074 | kgdb_contthread = NULL; | |
1075 | } else { | |
1076 | thread = getthread(ks->linux_regs, ks->threadid); | |
1077 | if (!thread && ks->threadid > 0) { | |
1078 | error_packet(remcom_out_buffer, -EINVAL); | |
1079 | break; | |
1080 | } | |
1081 | kgdb_contthread = thread; | |
1082 | } | |
1083 | strcpy(remcom_out_buffer, "OK"); | |
1084 | break; | |
1085 | } | |
1086 | } | |
1087 | ||
1088 | /* Handle the 'T' thread query packets */ | |
1089 | static void gdb_cmd_thread(struct kgdb_state *ks) | |
1090 | { | |
1091 | char *ptr = &remcom_in_buffer[1]; | |
1092 | struct task_struct *thread; | |
1093 | ||
1094 | kgdb_hex2long(&ptr, &ks->threadid); | |
1095 | thread = getthread(ks->linux_regs, ks->threadid); | |
1096 | if (thread) | |
1097 | strcpy(remcom_out_buffer, "OK"); | |
1098 | else | |
1099 | error_packet(remcom_out_buffer, -EINVAL); | |
1100 | } | |
1101 | ||
1102 | /* Handle the 'z' or 'Z' breakpoint remove or set packets */ | |
1103 | static void gdb_cmd_break(struct kgdb_state *ks) | |
1104 | { | |
1105 | /* | |
1106 | * Since GDB-5.3, it's been drafted that '0' is a software | |
1107 | * breakpoint, '1' is a hardware breakpoint, so let's do that. | |
1108 | */ | |
1109 | char *bpt_type = &remcom_in_buffer[1]; | |
1110 | char *ptr = &remcom_in_buffer[2]; | |
1111 | unsigned long addr; | |
1112 | unsigned long length; | |
1113 | int error = 0; | |
1114 | ||
1115 | if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') { | |
1116 | /* Unsupported */ | |
1117 | if (*bpt_type > '4') | |
1118 | return; | |
1119 | } else { | |
1120 | if (*bpt_type != '0' && *bpt_type != '1') | |
1121 | /* Unsupported. */ | |
1122 | return; | |
1123 | } | |
1124 | ||
1125 | /* | |
1126 | * Test if this is a hardware breakpoint, and | |
1127 | * if we support it: | |
1128 | */ | |
1129 | if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT)) | |
1130 | /* Unsupported. */ | |
1131 | return; | |
1132 | ||
1133 | if (*(ptr++) != ',') { | |
1134 | error_packet(remcom_out_buffer, -EINVAL); | |
1135 | return; | |
1136 | } | |
1137 | if (!kgdb_hex2long(&ptr, &addr)) { | |
1138 | error_packet(remcom_out_buffer, -EINVAL); | |
1139 | return; | |
1140 | } | |
1141 | if (*(ptr++) != ',' || | |
1142 | !kgdb_hex2long(&ptr, &length)) { | |
1143 | error_packet(remcom_out_buffer, -EINVAL); | |
1144 | return; | |
1145 | } | |
1146 | ||
1147 | if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0') | |
1148 | error = kgdb_set_sw_break(addr); | |
1149 | else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0') | |
1150 | error = kgdb_remove_sw_break(addr); | |
1151 | else if (remcom_in_buffer[0] == 'Z') | |
1152 | error = arch_kgdb_ops.set_hw_breakpoint(addr, | |
64e9ee30 | 1153 | (int)length, *bpt_type - '0'); |
dc7d5527 JW |
1154 | else if (remcom_in_buffer[0] == 'z') |
1155 | error = arch_kgdb_ops.remove_hw_breakpoint(addr, | |
64e9ee30 | 1156 | (int) length, *bpt_type - '0'); |
dc7d5527 JW |
1157 | |
1158 | if (error == 0) | |
1159 | strcpy(remcom_out_buffer, "OK"); | |
1160 | else | |
1161 | error_packet(remcom_out_buffer, error); | |
1162 | } | |
1163 | ||
1164 | /* Handle the 'C' signal / exception passing packets */ | |
1165 | static int gdb_cmd_exception_pass(struct kgdb_state *ks) | |
1166 | { | |
1167 | /* C09 == pass exception | |
1168 | * C15 == detach kgdb, pass exception | |
1169 | */ | |
1170 | if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') { | |
1171 | ||
1172 | ks->pass_exception = 1; | |
1173 | remcom_in_buffer[0] = 'c'; | |
1174 | ||
1175 | } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') { | |
1176 | ||
1177 | ks->pass_exception = 1; | |
1178 | remcom_in_buffer[0] = 'D'; | |
1179 | remove_all_break(); | |
1180 | kgdb_connected = 0; | |
1181 | return 1; | |
1182 | ||
1183 | } else { | |
1184 | error_packet(remcom_out_buffer, -EINVAL); | |
1185 | return 0; | |
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(); | |
67baf94c JW |
1341 | printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed %lx\n", |
1342 | addr); | |
dc7d5527 JW |
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 | /* | |
1363 | * kgdb_handle_exception() - main entry point from a kernel exception | |
1364 | * | |
1365 | * Locking hierarchy: | |
1366 | * interface locks, if any (begin_session) | |
1367 | * kgdb lock (kgdb_active) | |
1368 | */ | |
1369 | int | |
1370 | kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) | |
1371 | { | |
1372 | struct kgdb_state kgdb_var; | |
1373 | struct kgdb_state *ks = &kgdb_var; | |
1374 | unsigned long flags; | |
1375 | int error = 0; | |
1376 | int i, cpu; | |
1377 | ||
1378 | ks->cpu = raw_smp_processor_id(); | |
1379 | ks->ex_vector = evector; | |
1380 | ks->signo = signo; | |
1381 | ks->ex_vector = evector; | |
1382 | ks->err_code = ecode; | |
1383 | ks->kgdb_usethreadid = 0; | |
1384 | ks->linux_regs = regs; | |
1385 | ||
1386 | if (kgdb_reenter_check(ks)) | |
1387 | return 0; /* Ouch, double exception ! */ | |
1388 | ||
1389 | acquirelock: | |
1390 | /* | |
1391 | * Interrupts will be restored by the 'trap return' code, except when | |
1392 | * single stepping. | |
1393 | */ | |
1394 | local_irq_save(flags); | |
1395 | ||
1396 | cpu = raw_smp_processor_id(); | |
1397 | ||
1398 | /* | |
1399 | * Acquire the kgdb_active lock: | |
1400 | */ | |
1401 | while (atomic_cmpxchg(&kgdb_active, -1, cpu) != -1) | |
1402 | cpu_relax(); | |
1403 | ||
1404 | /* | |
1405 | * Do not start the debugger connection on this CPU if the last | |
1406 | * instance of the exception handler wanted to come into the | |
1407 | * debugger on a different CPU via a single step | |
1408 | */ | |
1409 | if (atomic_read(&kgdb_cpu_doing_single_step) != -1 && | |
1410 | atomic_read(&kgdb_cpu_doing_single_step) != cpu) { | |
1411 | ||
1412 | atomic_set(&kgdb_active, -1); | |
7c3078b6 | 1413 | clocksource_touch_watchdog(); |
dc7d5527 JW |
1414 | local_irq_restore(flags); |
1415 | ||
1416 | goto acquirelock; | |
1417 | } | |
1418 | ||
1419 | if (!kgdb_io_ready(1)) { | |
1420 | error = 1; | |
1421 | goto kgdb_restore; /* No I/O connection, so resume the system */ | |
1422 | } | |
1423 | ||
1424 | /* | |
1425 | * Don't enter if we have hit a removed breakpoint. | |
1426 | */ | |
1427 | if (kgdb_skipexception(ks->ex_vector, ks->linux_regs)) | |
1428 | goto kgdb_restore; | |
1429 | ||
1430 | /* Call the I/O driver's pre_exception routine */ | |
1431 | if (kgdb_io_ops->pre_exception) | |
1432 | kgdb_io_ops->pre_exception(); | |
1433 | ||
1434 | kgdb_info[ks->cpu].debuggerinfo = ks->linux_regs; | |
1435 | kgdb_info[ks->cpu].task = current; | |
1436 | ||
1437 | kgdb_disable_hw_debug(ks->linux_regs); | |
1438 | ||
1439 | /* | |
1440 | * Get the passive CPU lock which will hold all the non-primary | |
1441 | * CPU in a spin state while the debugger is active | |
1442 | */ | |
1443 | if (!kgdb_single_step || !kgdb_contthread) { | |
1444 | for (i = 0; i < NR_CPUS; i++) | |
1445 | atomic_set(&passive_cpu_wait[i], 1); | |
1446 | } | |
1447 | ||
1448 | #ifdef CONFIG_SMP | |
1449 | /* Signal the other CPUs to enter kgdb_wait() */ | |
1450 | if ((!kgdb_single_step || !kgdb_contthread) && kgdb_do_roundup) | |
1451 | kgdb_roundup_cpus(flags); | |
1452 | #endif | |
1453 | ||
1454 | /* | |
1455 | * spin_lock code is good enough as a barrier so we don't | |
1456 | * need one here: | |
1457 | */ | |
1458 | atomic_set(&cpu_in_kgdb[ks->cpu], 1); | |
1459 | ||
1460 | /* | |
1461 | * Wait for the other CPUs to be notified and be waiting for us: | |
1462 | */ | |
1463 | for_each_online_cpu(i) { | |
1464 | while (!atomic_read(&cpu_in_kgdb[i])) | |
1465 | cpu_relax(); | |
1466 | } | |
1467 | ||
1468 | /* | |
1469 | * At this point the primary processor is completely | |
1470 | * in the debugger and all secondary CPUs are quiescent | |
1471 | */ | |
1472 | kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code); | |
1473 | kgdb_deactivate_sw_breakpoints(); | |
1474 | kgdb_single_step = 0; | |
1475 | kgdb_contthread = NULL; | |
1476 | exception_level = 0; | |
1477 | ||
1478 | /* Talk to debugger with gdbserial protocol */ | |
1479 | error = gdb_serial_stub(ks); | |
1480 | ||
1481 | /* Call the I/O driver's post_exception routine */ | |
1482 | if (kgdb_io_ops->post_exception) | |
1483 | kgdb_io_ops->post_exception(); | |
1484 | ||
1485 | kgdb_info[ks->cpu].debuggerinfo = NULL; | |
1486 | kgdb_info[ks->cpu].task = NULL; | |
1487 | atomic_set(&cpu_in_kgdb[ks->cpu], 0); | |
1488 | ||
1489 | if (!kgdb_single_step || !kgdb_contthread) { | |
1490 | for (i = NR_CPUS-1; i >= 0; i--) | |
1491 | atomic_set(&passive_cpu_wait[i], 0); | |
1492 | /* | |
1493 | * Wait till all the CPUs have quit | |
1494 | * from the debugger. | |
1495 | */ | |
1496 | for_each_online_cpu(i) { | |
1497 | while (atomic_read(&cpu_in_kgdb[i])) | |
1498 | cpu_relax(); | |
1499 | } | |
1500 | } | |
1501 | ||
1502 | kgdb_restore: | |
1503 | /* Free kgdb_active */ | |
1504 | atomic_set(&kgdb_active, -1); | |
7c3078b6 | 1505 | clocksource_touch_watchdog(); |
dc7d5527 JW |
1506 | local_irq_restore(flags); |
1507 | ||
1508 | return error; | |
1509 | } | |
1510 | ||
1511 | int kgdb_nmicallback(int cpu, void *regs) | |
1512 | { | |
1513 | #ifdef CONFIG_SMP | |
1514 | if (!atomic_read(&cpu_in_kgdb[cpu]) && | |
1515 | atomic_read(&kgdb_active) != cpu) { | |
1516 | kgdb_wait((struct pt_regs *)regs); | |
1517 | return 0; | |
1518 | } | |
1519 | #endif | |
1520 | return 1; | |
1521 | } | |
1522 | ||
1523 | void kgdb_console_write(struct console *co, const char *s, unsigned count) | |
1524 | { | |
1525 | unsigned long flags; | |
1526 | ||
1527 | /* If we're debugging, or KGDB has not connected, don't try | |
1528 | * and print. */ | |
1529 | if (!kgdb_connected || atomic_read(&kgdb_active) != -1) | |
1530 | return; | |
1531 | ||
1532 | local_irq_save(flags); | |
1533 | kgdb_msg_write(s, count); | |
1534 | local_irq_restore(flags); | |
1535 | } | |
1536 | ||
1537 | static struct console kgdbcons = { | |
1538 | .name = "kgdb", | |
1539 | .write = kgdb_console_write, | |
1540 | .flags = CON_PRINTBUFFER | CON_ENABLED, | |
1541 | .index = -1, | |
1542 | }; | |
1543 | ||
1544 | #ifdef CONFIG_MAGIC_SYSRQ | |
1545 | static void sysrq_handle_gdb(int key, struct tty_struct *tty) | |
1546 | { | |
1547 | if (!kgdb_io_ops) { | |
1548 | printk(KERN_CRIT "ERROR: No KGDB I/O module available\n"); | |
1549 | return; | |
1550 | } | |
1551 | if (!kgdb_connected) | |
1552 | printk(KERN_CRIT "Entering KGDB\n"); | |
1553 | ||
1554 | kgdb_breakpoint(); | |
1555 | } | |
1556 | ||
1557 | static struct sysrq_key_op sysrq_gdb_op = { | |
1558 | .handler = sysrq_handle_gdb, | |
1559 | .help_msg = "Gdb", | |
1560 | .action_msg = "GDB", | |
1561 | }; | |
1562 | #endif | |
1563 | ||
1564 | static void kgdb_register_callbacks(void) | |
1565 | { | |
1566 | if (!kgdb_io_module_registered) { | |
1567 | kgdb_io_module_registered = 1; | |
1568 | kgdb_arch_init(); | |
1569 | #ifdef CONFIG_MAGIC_SYSRQ | |
1570 | register_sysrq_key('g', &sysrq_gdb_op); | |
1571 | #endif | |
1572 | if (kgdb_use_con && !kgdb_con_registered) { | |
1573 | register_console(&kgdbcons); | |
1574 | kgdb_con_registered = 1; | |
1575 | } | |
1576 | } | |
1577 | } | |
1578 | ||
1579 | static void kgdb_unregister_callbacks(void) | |
1580 | { | |
1581 | /* | |
1582 | * When this routine is called KGDB should unregister from the | |
1583 | * panic handler and clean up, making sure it is not handling any | |
1584 | * break exceptions at the time. | |
1585 | */ | |
1586 | if (kgdb_io_module_registered) { | |
1587 | kgdb_io_module_registered = 0; | |
1588 | kgdb_arch_exit(); | |
1589 | #ifdef CONFIG_MAGIC_SYSRQ | |
1590 | unregister_sysrq_key('g', &sysrq_gdb_op); | |
1591 | #endif | |
1592 | if (kgdb_con_registered) { | |
1593 | unregister_console(&kgdbcons); | |
1594 | kgdb_con_registered = 0; | |
1595 | } | |
1596 | } | |
1597 | } | |
1598 | ||
1599 | static void kgdb_initial_breakpoint(void) | |
1600 | { | |
1601 | kgdb_break_asap = 0; | |
1602 | ||
1603 | printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n"); | |
1604 | kgdb_breakpoint(); | |
1605 | } | |
1606 | ||
1607 | /** | |
1608 | * kkgdb_register_io_module - register KGDB IO module | |
1609 | * @new_kgdb_io_ops: the io ops vector | |
1610 | * | |
1611 | * Register it with the KGDB core. | |
1612 | */ | |
1613 | int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops) | |
1614 | { | |
1615 | int err; | |
1616 | ||
1617 | spin_lock(&kgdb_registration_lock); | |
1618 | ||
1619 | if (kgdb_io_ops) { | |
1620 | spin_unlock(&kgdb_registration_lock); | |
1621 | ||
1622 | printk(KERN_ERR "kgdb: Another I/O driver is already " | |
1623 | "registered with KGDB.\n"); | |
1624 | return -EBUSY; | |
1625 | } | |
1626 | ||
1627 | if (new_kgdb_io_ops->init) { | |
1628 | err = new_kgdb_io_ops->init(); | |
1629 | if (err) { | |
1630 | spin_unlock(&kgdb_registration_lock); | |
1631 | return err; | |
1632 | } | |
1633 | } | |
1634 | ||
1635 | kgdb_io_ops = new_kgdb_io_ops; | |
1636 | ||
1637 | spin_unlock(&kgdb_registration_lock); | |
1638 | ||
1639 | printk(KERN_INFO "kgdb: Registered I/O driver %s.\n", | |
1640 | new_kgdb_io_ops->name); | |
1641 | ||
1642 | /* Arm KGDB now. */ | |
1643 | kgdb_register_callbacks(); | |
1644 | ||
1645 | if (kgdb_break_asap) | |
1646 | kgdb_initial_breakpoint(); | |
1647 | ||
1648 | return 0; | |
1649 | } | |
1650 | EXPORT_SYMBOL_GPL(kgdb_register_io_module); | |
1651 | ||
1652 | /** | |
1653 | * kkgdb_unregister_io_module - unregister KGDB IO module | |
1654 | * @old_kgdb_io_ops: the io ops vector | |
1655 | * | |
1656 | * Unregister it with the KGDB core. | |
1657 | */ | |
1658 | void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops) | |
1659 | { | |
1660 | BUG_ON(kgdb_connected); | |
1661 | ||
1662 | /* | |
1663 | * KGDB is no longer able to communicate out, so | |
1664 | * unregister our callbacks and reset state. | |
1665 | */ | |
1666 | kgdb_unregister_callbacks(); | |
1667 | ||
1668 | spin_lock(&kgdb_registration_lock); | |
1669 | ||
1670 | WARN_ON_ONCE(kgdb_io_ops != old_kgdb_io_ops); | |
1671 | kgdb_io_ops = NULL; | |
1672 | ||
1673 | spin_unlock(&kgdb_registration_lock); | |
1674 | ||
1675 | printk(KERN_INFO | |
1676 | "kgdb: Unregistered I/O driver %s, debugger disabled.\n", | |
1677 | old_kgdb_io_ops->name); | |
1678 | } | |
1679 | EXPORT_SYMBOL_GPL(kgdb_unregister_io_module); | |
1680 | ||
1681 | /** | |
1682 | * kgdb_breakpoint - generate breakpoint exception | |
1683 | * | |
1684 | * This function will generate a breakpoint exception. It is used at the | |
1685 | * beginning of a program to sync up with a debugger and can be used | |
1686 | * otherwise as a quick means to stop program execution and "break" into | |
1687 | * the debugger. | |
1688 | */ | |
1689 | void kgdb_breakpoint(void) | |
1690 | { | |
1691 | atomic_set(&kgdb_setting_breakpoint, 1); | |
1692 | wmb(); /* Sync point before breakpoint */ | |
1693 | arch_kgdb_breakpoint(); | |
1694 | wmb(); /* Sync point after breakpoint */ | |
1695 | atomic_set(&kgdb_setting_breakpoint, 0); | |
1696 | } | |
1697 | EXPORT_SYMBOL_GPL(kgdb_breakpoint); | |
1698 | ||
1699 | static int __init opt_kgdb_wait(char *str) | |
1700 | { | |
1701 | kgdb_break_asap = 1; | |
1702 | ||
1703 | if (kgdb_io_module_registered) | |
1704 | kgdb_initial_breakpoint(); | |
1705 | ||
1706 | return 0; | |
1707 | } | |
1708 | ||
1709 | early_param("kgdbwait", opt_kgdb_wait); |