1 /*
2 * Kernel Debugger Architecture Independent Breakpoint Handler
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
6 * for more details.
7 *
8 * Copyright (c) 1999-2004 Silicon Graphics, Inc. All Rights Reserved.
9 * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
10 */
11
12 #include <linux/string.h>
13 #include <linux/kernel.h>
14 #include <linux/init.h>
15 #include <linux/kdb.h>
16 #include <linux/kgdb.h>
17 #include <linux/smp.h>
18 #include <linux/sched.h>
19 #include <linux/interrupt.h>
20 #include "kdb_private.h"
21
22 /*
23 * Table of kdb_breakpoints
24 */
25 kdb_bp_t kdb_breakpoints[KDB_MAXBPT];
26
kdb_setsinglestep(struct pt_regs * regs)27 static void kdb_setsinglestep(struct pt_regs *regs)
28 {
29 KDB_STATE_SET(DOING_SS);
30 }
31
32 static char *kdb_rwtypes[] = {
33 "Instruction(i)",
34 "Instruction(Register)",
35 "Data Write",
36 "I/O",
37 "Data Access"
38 };
39
kdb_bptype(kdb_bp_t * bp)40 static char *kdb_bptype(kdb_bp_t *bp)
41 {
42 if (bp->bp_type < 0 || bp->bp_type > 4)
43 return "";
44
45 return kdb_rwtypes[bp->bp_type];
46 }
47
kdb_parsebp(int argc,const char ** argv,int * nextargp,kdb_bp_t * bp)48 static int kdb_parsebp(int argc, const char **argv, int *nextargp, kdb_bp_t *bp)
49 {
50 int nextarg = *nextargp;
51 int diag;
52
53 bp->bph_length = 1;
54 if ((argc + 1) != nextarg) {
55 if (strncasecmp(argv[nextarg], "datar", sizeof("datar")) == 0)
56 bp->bp_type = BP_ACCESS_WATCHPOINT;
57 else if (strncasecmp(argv[nextarg], "dataw", sizeof("dataw")) == 0)
58 bp->bp_type = BP_WRITE_WATCHPOINT;
59 else if (strncasecmp(argv[nextarg], "inst", sizeof("inst")) == 0)
60 bp->bp_type = BP_HARDWARE_BREAKPOINT;
61 else
62 return KDB_ARGCOUNT;
63
64 bp->bph_length = 1;
65
66 nextarg++;
67
68 if ((argc + 1) != nextarg) {
69 unsigned long len;
70
71 diag = kdbgetularg((char *)argv[nextarg],
72 &len);
73 if (diag)
74 return diag;
75
76
77 if (len > 8)
78 return KDB_BADLENGTH;
79
80 bp->bph_length = len;
81 nextarg++;
82 }
83
84 if ((argc + 1) != nextarg)
85 return KDB_ARGCOUNT;
86 }
87
88 *nextargp = nextarg;
89 return 0;
90 }
91
_kdb_bp_remove(kdb_bp_t * bp)92 static int _kdb_bp_remove(kdb_bp_t *bp)
93 {
94 int ret = 1;
95 if (!bp->bp_installed)
96 return ret;
97 if (!bp->bp_type)
98 ret = dbg_remove_sw_break(bp->bp_addr);
99 else
100 ret = arch_kgdb_ops.remove_hw_breakpoint(bp->bp_addr,
101 bp->bph_length,
102 bp->bp_type);
103 if (ret == 0)
104 bp->bp_installed = 0;
105 return ret;
106 }
107
kdb_handle_bp(struct pt_regs * regs,kdb_bp_t * bp)108 static void kdb_handle_bp(struct pt_regs *regs, kdb_bp_t *bp)
109 {
110 if (KDB_DEBUG(BP))
111 kdb_printf("regs->ip = 0x%lx\n", instruction_pointer(regs));
112
113 /*
114 * Setup single step
115 */
116 kdb_setsinglestep(regs);
117
118 /*
119 * Reset delay attribute
120 */
121 bp->bp_delay = 0;
122 bp->bp_delayed = 1;
123 }
124
_kdb_bp_install(struct pt_regs * regs,kdb_bp_t * bp)125 static int _kdb_bp_install(struct pt_regs *regs, kdb_bp_t *bp)
126 {
127 int ret;
128 /*
129 * Install the breakpoint, if it is not already installed.
130 */
131
132 if (KDB_DEBUG(BP))
133 kdb_printf("%s: bp_installed %d\n",
134 __func__, bp->bp_installed);
135 if (!KDB_STATE(SSBPT))
136 bp->bp_delay = 0;
137 if (bp->bp_installed)
138 return 1;
139 if (bp->bp_delay || (bp->bp_delayed && KDB_STATE(DOING_SS))) {
140 if (KDB_DEBUG(BP))
141 kdb_printf("%s: delayed bp\n", __func__);
142 kdb_handle_bp(regs, bp);
143 return 0;
144 }
145 if (!bp->bp_type)
146 ret = dbg_set_sw_break(bp->bp_addr);
147 else
148 ret = arch_kgdb_ops.set_hw_breakpoint(bp->bp_addr,
149 bp->bph_length,
150 bp->bp_type);
151 if (ret == 0) {
152 bp->bp_installed = 1;
153 } else {
154 kdb_printf("%s: failed to set breakpoint at 0x%lx\n",
155 __func__, bp->bp_addr);
156 if (!bp->bp_type) {
157 kdb_printf("Software breakpoints are unavailable.\n"
158 " Boot the kernel with rodata=off\n"
159 " OR use hw breaks: help bph\n");
160 }
161 return 1;
162 }
163 return 0;
164 }
165
166 /*
167 * kdb_bp_install
168 *
169 * Install kdb_breakpoints prior to returning from the
170 * kernel debugger. This allows the kdb_breakpoints to be set
171 * upon functions that are used internally by kdb, such as
172 * printk(). This function is only called once per kdb session.
173 */
kdb_bp_install(struct pt_regs * regs)174 void kdb_bp_install(struct pt_regs *regs)
175 {
176 int i;
177
178 for (i = 0; i < KDB_MAXBPT; i++) {
179 kdb_bp_t *bp = &kdb_breakpoints[i];
180
181 if (KDB_DEBUG(BP)) {
182 kdb_printf("%s: bp %d bp_enabled %d\n",
183 __func__, i, bp->bp_enabled);
184 }
185 if (bp->bp_enabled)
186 _kdb_bp_install(regs, bp);
187 }
188 }
189
190 /*
191 * kdb_bp_remove
192 *
193 * Remove kdb_breakpoints upon entry to the kernel debugger.
194 *
195 * Parameters:
196 * None.
197 * Outputs:
198 * None.
199 * Returns:
200 * None.
201 * Locking:
202 * None.
203 * Remarks:
204 */
kdb_bp_remove(void)205 void kdb_bp_remove(void)
206 {
207 int i;
208
209 for (i = KDB_MAXBPT - 1; i >= 0; i--) {
210 kdb_bp_t *bp = &kdb_breakpoints[i];
211
212 if (KDB_DEBUG(BP)) {
213 kdb_printf("%s: bp %d bp_enabled %d\n",
214 __func__, i, bp->bp_enabled);
215 }
216 if (bp->bp_enabled)
217 _kdb_bp_remove(bp);
218 }
219 }
220
221
222 /*
223 * kdb_printbp
224 *
225 * Internal function to format and print a breakpoint entry.
226 *
227 * Parameters:
228 * None.
229 * Outputs:
230 * None.
231 * Returns:
232 * None.
233 * Locking:
234 * None.
235 * Remarks:
236 */
237
kdb_printbp(kdb_bp_t * bp,int i)238 static void kdb_printbp(kdb_bp_t *bp, int i)
239 {
240 kdb_printf("%s ", kdb_bptype(bp));
241 kdb_printf("BP #%d at ", i);
242 kdb_symbol_print(bp->bp_addr, NULL, KDB_SP_DEFAULT);
243
244 if (bp->bp_enabled)
245 kdb_printf("\n is enabled ");
246 else
247 kdb_printf("\n is disabled");
248
249 kdb_printf(" addr at %016lx, hardtype=%d installed=%d\n",
250 bp->bp_addr, bp->bp_type, bp->bp_installed);
251
252 kdb_printf("\n");
253 }
254
255 /*
256 * kdb_bp
257 *
258 * Handle the bp commands.
259 *
260 * [bp|bph] <addr-expression> [DATAR|DATAW]
261 *
262 * Parameters:
263 * argc Count of arguments in argv
264 * argv Space delimited command line arguments
265 * Outputs:
266 * None.
267 * Returns:
268 * Zero for success, a kdb diagnostic if failure.
269 * Locking:
270 * None.
271 * Remarks:
272 *
273 * bp Set breakpoint on all cpus. Only use hardware assist if need.
274 * bph Set breakpoint on all cpus. Force hardware register
275 */
276
kdb_bp(int argc,const char ** argv)277 static int kdb_bp(int argc, const char **argv)
278 {
279 int i, bpno;
280 kdb_bp_t *bp, *bp_check;
281 int diag;
282 char *symname = NULL;
283 long offset = 0ul;
284 int nextarg;
285 kdb_bp_t template = {0};
286
287 if (argc == 0) {
288 /*
289 * Display breakpoint table
290 */
291 for (bpno = 0, bp = kdb_breakpoints; bpno < KDB_MAXBPT;
292 bpno++, bp++) {
293 if (bp->bp_free)
294 continue;
295 kdb_printbp(bp, bpno);
296 }
297
298 return 0;
299 }
300
301 nextarg = 1;
302 diag = kdbgetaddrarg(argc, argv, &nextarg, &template.bp_addr,
303 &offset, &symname);
304 if (diag)
305 return diag;
306 if (!template.bp_addr)
307 return KDB_BADINT;
308
309 /*
310 * Find an empty bp structure to allocate
311 */
312 for (bpno = 0, bp = kdb_breakpoints; bpno < KDB_MAXBPT; bpno++, bp++) {
313 if (bp->bp_free)
314 break;
315 }
316
317 if (bpno == KDB_MAXBPT)
318 return KDB_TOOMANYBPT;
319
320 if (strcmp(argv[0], "bph") == 0) {
321 template.bp_type = BP_HARDWARE_BREAKPOINT;
322 diag = kdb_parsebp(argc, argv, &nextarg, &template);
323 if (diag)
324 return diag;
325 } else {
326 template.bp_type = BP_BREAKPOINT;
327 }
328
329 /*
330 * Check for clashing breakpoints.
331 *
332 * Note, in this design we can't have hardware breakpoints
333 * enabled for both read and write on the same address.
334 */
335 for (i = 0, bp_check = kdb_breakpoints; i < KDB_MAXBPT;
336 i++, bp_check++) {
337 if (!bp_check->bp_free &&
338 bp_check->bp_addr == template.bp_addr) {
339 kdb_printf("You already have a breakpoint at "
340 kdb_bfd_vma_fmt0 "\n", template.bp_addr);
341 return KDB_DUPBPT;
342 }
343 }
344
345 template.bp_enabled = 1;
346
347 /*
348 * Actually allocate the breakpoint found earlier
349 */
350 *bp = template;
351 bp->bp_free = 0;
352
353 kdb_printbp(bp, bpno);
354
355 return 0;
356 }
357
358 /*
359 * kdb_bc
360 *
361 * Handles the 'bc', 'be', and 'bd' commands
362 *
363 * [bd|bc|be] <breakpoint-number>
364 * [bd|bc|be] *
365 *
366 * Parameters:
367 * argc Count of arguments in argv
368 * argv Space delimited command line arguments
369 * Outputs:
370 * None.
371 * Returns:
372 * Zero for success, a kdb diagnostic for failure
373 * Locking:
374 * None.
375 * Remarks:
376 */
kdb_bc(int argc,const char ** argv)377 static int kdb_bc(int argc, const char **argv)
378 {
379 unsigned long addr;
380 kdb_bp_t *bp = NULL;
381 int lowbp = KDB_MAXBPT;
382 int highbp = 0;
383 int done = 0;
384 int i;
385 int diag = 0;
386
387 int cmd; /* KDBCMD_B? */
388 #define KDBCMD_BC 0
389 #define KDBCMD_BE 1
390 #define KDBCMD_BD 2
391
392 if (strcmp(argv[0], "be") == 0)
393 cmd = KDBCMD_BE;
394 else if (strcmp(argv[0], "bd") == 0)
395 cmd = KDBCMD_BD;
396 else
397 cmd = KDBCMD_BC;
398
399 if (argc != 1)
400 return KDB_ARGCOUNT;
401
402 if (strcmp(argv[1], "*") == 0) {
403 lowbp = 0;
404 highbp = KDB_MAXBPT;
405 } else {
406 diag = kdbgetularg(argv[1], &addr);
407 if (diag)
408 return diag;
409
410 /*
411 * For addresses less than the maximum breakpoint number,
412 * assume that the breakpoint number is desired.
413 */
414 if (addr < KDB_MAXBPT) {
415 bp = &kdb_breakpoints[addr];
416 lowbp = highbp = addr;
417 highbp++;
418 } else {
419 for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT;
420 i++, bp++) {
421 if (bp->bp_addr == addr) {
422 lowbp = highbp = i;
423 highbp++;
424 break;
425 }
426 }
427 }
428 }
429
430 /*
431 * Now operate on the set of breakpoints matching the input
432 * criteria (either '*' for all, or an individual breakpoint).
433 */
434 for (bp = &kdb_breakpoints[lowbp], i = lowbp;
435 i < highbp;
436 i++, bp++) {
437 if (bp->bp_free)
438 continue;
439
440 done++;
441
442 switch (cmd) {
443 case KDBCMD_BC:
444 bp->bp_enabled = 0;
445
446 kdb_printf("Breakpoint %d at "
447 kdb_bfd_vma_fmt " cleared\n",
448 i, bp->bp_addr);
449
450 bp->bp_addr = 0;
451 bp->bp_free = 1;
452
453 break;
454 case KDBCMD_BE:
455 bp->bp_enabled = 1;
456
457 kdb_printf("Breakpoint %d at "
458 kdb_bfd_vma_fmt " enabled",
459 i, bp->bp_addr);
460
461 kdb_printf("\n");
462 break;
463 case KDBCMD_BD:
464 if (!bp->bp_enabled)
465 break;
466
467 bp->bp_enabled = 0;
468
469 kdb_printf("Breakpoint %d at "
470 kdb_bfd_vma_fmt " disabled\n",
471 i, bp->bp_addr);
472
473 break;
474 }
475 if (bp->bp_delay && (cmd == KDBCMD_BC || cmd == KDBCMD_BD)) {
476 bp->bp_delay = 0;
477 KDB_STATE_CLEAR(SSBPT);
478 }
479 }
480
481 return (!done) ? KDB_BPTNOTFOUND : 0;
482 }
483
484 /*
485 * kdb_ss
486 *
487 * Process the 'ss' (Single Step) command.
488 *
489 * ss
490 *
491 * Parameters:
492 * argc Argument count
493 * argv Argument vector
494 * Outputs:
495 * None.
496 * Returns:
497 * KDB_CMD_SS for success, a kdb error if failure.
498 * Locking:
499 * None.
500 * Remarks:
501 *
502 * Set the arch specific option to trigger a debug trap after the next
503 * instruction.
504 */
505
kdb_ss(int argc,const char ** argv)506 static int kdb_ss(int argc, const char **argv)
507 {
508 if (argc != 0)
509 return KDB_ARGCOUNT;
510 /*
511 * Set trace flag and go.
512 */
513 KDB_STATE_SET(DOING_SS);
514 return KDB_CMD_SS;
515 }
516
517 /* Initialize the breakpoint table and register breakpoint commands. */
518
kdb_initbptab(void)519 void __init kdb_initbptab(void)
520 {
521 int i;
522 kdb_bp_t *bp;
523
524 /*
525 * First time initialization.
526 */
527 memset(&kdb_breakpoints, '\0', sizeof(kdb_breakpoints));
528
529 for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++)
530 bp->bp_free = 1;
531
532 kdb_register_flags("bp", kdb_bp, "[<vaddr>]",
533 "Set/Display breakpoints", 0,
534 KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS);
535 kdb_register_flags("bl", kdb_bp, "[<vaddr>]",
536 "Display breakpoints", 0,
537 KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS);
538 if (arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT)
539 kdb_register_flags("bph", kdb_bp, "[<vaddr>]",
540 "[datar [length]|dataw [length]] Set hw brk", 0,
541 KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS);
542 kdb_register_flags("bc", kdb_bc, "<bpnum>",
543 "Clear Breakpoint", 0,
544 KDB_ENABLE_FLOW_CTRL);
545 kdb_register_flags("be", kdb_bc, "<bpnum>",
546 "Enable Breakpoint", 0,
547 KDB_ENABLE_FLOW_CTRL);
548 kdb_register_flags("bd", kdb_bc, "<bpnum>",
549 "Disable Breakpoint", 0,
550 KDB_ENABLE_FLOW_CTRL);
551
552 kdb_register_flags("ss", kdb_ss, "",
553 "Single Step", 1,
554 KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS);
555 /*
556 * Architecture dependent initialization.
557 */
558 }
559
