summaryrefslogtreecommitdiff
path: root/kernel/debug/kdb/kdb_bp.c
blob: 90ff129c88a27c50e33be234be695650e7210494 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
/*
 * Kernel Debugger Architecture Independent Breakpoint Handler
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (c) 1999-2004 Silicon Graphics, Inc.  All Rights Reserved.
 * Copyright (c) 2009 Wind River Systems, Inc.  All Rights Reserved.
 */

#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/kdb.h>
#include <linux/kgdb.h>
#include <linux/smp.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include "kdb_private.h"

/*
 * Table of kdb_breakpoints
 */
kdb_bp_t kdb_breakpoints[KDB_MAXBPT];

static void kdb_setsinglestep(struct pt_regs *regs)
{
	KDB_STATE_SET(DOING_SS);
}

static char *kdb_rwtypes[] = {
	"Instruction(i)",
	"Instruction(Register)",
	"Data Write",
	"I/O",
	"Data Access"
};

static char *kdb_bptype(kdb_bp_t *bp)
{
	if (bp->bp_type < 0 || bp->bp_type > 4)
		return "";

	return kdb_rwtypes[bp->bp_type];
}

static int kdb_parsebp(int argc, const char **argv, int *nextargp, kdb_bp_t *bp)
{
	int nextarg = *nextargp;
	int diag;

	bp->bph_length = 1;
	if ((argc + 1) != nextarg) {
		if (strncasecmp(argv[nextarg], "datar", sizeof("datar")) == 0)
			bp->bp_type = BP_ACCESS_WATCHPOINT;
		else if (strncasecmp(argv[nextarg], "dataw", sizeof("dataw")) == 0)
			bp->bp_type = BP_WRITE_WATCHPOINT;
		else if (strncasecmp(argv[nextarg], "inst", sizeof("inst")) == 0)
			bp->bp_type = BP_HARDWARE_BREAKPOINT;
		else
			return KDB_ARGCOUNT;

		bp->bph_length = 1;

		nextarg++;

		if ((argc + 1) != nextarg) {
			unsigned long len;

			diag = kdbgetularg((char *)argv[nextarg],
					   &len);
			if (diag)
				return diag;


			if (len > 8)
				return KDB_BADLENGTH;

			bp->bph_length = len;
			nextarg++;
		}

		if ((argc + 1) != nextarg)
			return KDB_ARGCOUNT;
	}

	*nextargp = nextarg;
	return 0;
}

static int _kdb_bp_remove(kdb_bp_t *bp)
{
	int ret = 1;
	if (!bp->bp_installed)
		return ret;
	if (!bp->bp_type)
		ret = dbg_remove_sw_break(bp->bp_addr);
	else
		ret = arch_kgdb_ops.remove_hw_breakpoint(bp->bp_addr,
			 bp->bph_length,
			 bp->bp_type);
	if (ret == 0)
		bp->bp_installed = 0;
	return ret;
}

static void kdb_handle_bp(struct pt_regs *regs, kdb_bp_t *bp)
{
	if (KDB_DEBUG(BP))
		kdb_printf("regs->ip = 0x%lx\n", instruction_pointer(regs));

	/*
	 * Setup single step
	 */
	kdb_setsinglestep(regs);

	/*
	 * Reset delay attribute
	 */
	bp->bp_delay = 0;
	bp->bp_delayed = 1;
}

static int _kdb_bp_install(struct pt_regs *regs, kdb_bp_t *bp)
{
	int ret;
	/*
	 * Install the breakpoint, if it is not already installed.
	 */

	if (KDB_DEBUG(BP))
		kdb_printf("%s: bp_installed %d\n",
			   __func__, bp->bp_installed);
	if (!KDB_STATE(SSBPT))
		bp->bp_delay = 0;
	if (bp->bp_installed)
		return 1;
	if (bp->bp_delay || (bp->bp_delayed && KDB_STATE(DOING_SS))) {
		if (KDB_DEBUG(BP))
			kdb_printf("%s: delayed bp\n", __func__);
		kdb_handle_bp(regs, bp);
		return 0;
	}
	if (!bp->bp_type)
		ret = dbg_set_sw_break(bp->bp_addr);
	else
		ret = arch_kgdb_ops.set_hw_breakpoint(bp->bp_addr,
			 bp->bph_length,
			 bp->bp_type);
	if (ret == 0) {
		bp->bp_installed = 1;
	} else {
		kdb_printf("%s: failed to set breakpoint at 0x%lx\n",
			   __func__, bp->bp_addr);
		if (!bp->bp_type) {
			kdb_printf("Software breakpoints are unavailable.\n"
				   "  Boot the kernel with rodata=off\n"
				   "  OR use hw breaks: help bph\n");
		}
		return 1;
	}
	return 0;
}

/*
 * kdb_bp_install
 *
 *	Install kdb_breakpoints prior to returning from the
 *	kernel debugger.  This allows the kdb_breakpoints to be set
 *	upon functions that are used internally by kdb, such as
 *	printk().  This function is only called once per kdb session.
 */
void kdb_bp_install(struct pt_regs *regs)
{
	int i;

	for (i = 0; i < KDB_MAXBPT; i++) {
		kdb_bp_t *bp = &kdb_breakpoints[i];

		if (KDB_DEBUG(BP)) {
			kdb_printf("%s: bp %d bp_enabled %d\n",
				   __func__, i, bp->bp_enabled);
		}
		if (bp->bp_enabled)
			_kdb_bp_install(regs, bp);
	}
}

/*
 * kdb_bp_remove
 *
 *	Remove kdb_breakpoints upon entry to the kernel debugger.
 *
 * Parameters:
 *	None.
 * Outputs:
 *	None.
 * Returns:
 *	None.
 * Locking:
 *	None.
 * Remarks:
 */
void kdb_bp_remove(void)
{
	int i;

	for (i = KDB_MAXBPT - 1; i >= 0; i--) {
		kdb_bp_t *bp = &kdb_breakpoints[i];

		if (KDB_DEBUG(BP)) {
			kdb_printf("%s: bp %d bp_enabled %d\n",
				   __func__, i, bp->bp_enabled);
		}
		if (bp->bp_enabled)
			_kdb_bp_remove(bp);
	}
}


/*
 * kdb_printbp
 *
 *	Internal function to format and print a breakpoint entry.
 *
 * Parameters:
 *	None.
 * Outputs:
 *	None.
 * Returns:
 *	None.
 * Locking:
 *	None.
 * Remarks:
 */

static void kdb_printbp(kdb_bp_t *bp, int i)
{
	kdb_printf("%s ", kdb_bptype(bp));
	kdb_printf("BP #%d at ", i);
	kdb_symbol_print(bp->bp_addr, NULL, KDB_SP_DEFAULT);

	if (bp->bp_enabled)
		kdb_printf("\n    is enabled");
	else
		kdb_printf("\n    is disabled");

	kdb_printf("\taddr at %016lx, hardtype=%d installed=%d\n",
		   bp->bp_addr, bp->bp_type, bp->bp_installed);

	kdb_printf("\n");
}

/*
 * kdb_bp
 *
 *	Handle the bp commands.
 *
 *	[bp|bph] <addr-expression> [DATAR|DATAW]
 *
 * Parameters:
 *	argc	Count of arguments in argv
 *	argv	Space delimited command line arguments
 * Outputs:
 *	None.
 * Returns:
 *	Zero for success, a kdb diagnostic if failure.
 * Locking:
 *	None.
 * Remarks:
 *
 *	bp	Set breakpoint on all cpus.  Only use hardware assist if need.
 *	bph	Set breakpoint on all cpus.  Force hardware register
 */

static int kdb_bp(int argc, const char **argv)
{
	int i, bpno;
	kdb_bp_t *bp, *bp_check;
	int diag;
	char *symname = NULL;
	long offset = 0ul;
	int nextarg;
	kdb_bp_t template = {0};

	if (argc == 0) {
		/*
		 * Display breakpoint table
		 */
		for (bpno = 0, bp = kdb_breakpoints; bpno < KDB_MAXBPT;
		     bpno++, bp++) {
			if (bp->bp_free)
				continue;
			kdb_printbp(bp, bpno);
		}

		return 0;
	}

	nextarg = 1;
	diag = kdbgetaddrarg(argc, argv, &nextarg, &template.bp_addr,
			     &offset, &symname);
	if (diag)
		return diag;
	if (!template.bp_addr)
		return KDB_BADINT;

	/*
	 * Find an empty bp structure to allocate
	 */
	for (bpno = 0, bp = kdb_breakpoints; bpno < KDB_MAXBPT; bpno++, bp++) {
		if (bp->bp_free)
			break;
	}

	if (bpno == KDB_MAXBPT)
		return KDB_TOOMANYBPT;

	if (strcmp(argv[0], "bph") == 0) {
		template.bp_type = BP_HARDWARE_BREAKPOINT;
		diag = kdb_parsebp(argc, argv, &nextarg, &template);
		if (diag)
			return diag;
	} else {
		template.bp_type = BP_BREAKPOINT;
	}

	/*
	 * Check for clashing breakpoints.
	 *
	 * Note, in this design we can't have hardware breakpoints
	 * enabled for both read and write on the same address.
	 */
	for (i = 0, bp_check = kdb_breakpoints; i < KDB_MAXBPT;
	     i++, bp_check++) {
		if (!bp_check->bp_free &&
		    bp_check->bp_addr == template.bp_addr) {
			kdb_printf("You already have a breakpoint at "
				   kdb_bfd_vma_fmt0 "\n", template.bp_addr);
			return KDB_DUPBPT;
		}
	}

	template.bp_enabled = 1;

	/*
	 * Actually allocate the breakpoint found earlier
	 */
	*bp = template;
	bp->bp_free = 0;

	kdb_printbp(bp, bpno);

	return 0;
}

/*
 * kdb_bc
 *
 *	Handles the 'bc', 'be', and 'bd' commands
 *
 *	[bd|bc|be] <breakpoint-number>
 *	[bd|bc|be] *
 *
 * Parameters:
 *	argc	Count of arguments in argv
 *	argv	Space delimited command line arguments
 * Outputs:
 *	None.
 * Returns:
 *	Zero for success, a kdb diagnostic for failure
 * Locking:
 *	None.
 * Remarks:
 */
static int kdb_bc(int argc, const char **argv)
{
	unsigned long addr;
	kdb_bp_t *bp = NULL;
	int lowbp = KDB_MAXBPT;
	int highbp = 0;
	int done = 0;
	int i;
	int diag = 0;

	int cmd;			/* KDBCMD_B? */
#define KDBCMD_BC	0
#define KDBCMD_BE	1
#define KDBCMD_BD	2

	if (strcmp(argv[0], "be") == 0)
		cmd = KDBCMD_BE;
	else if (strcmp(argv[0], "bd") == 0)
		cmd = KDBCMD_BD;
	else
		cmd = KDBCMD_BC;

	if (argc != 1)
		return KDB_ARGCOUNT;

	if (strcmp(argv[1], "*") == 0) {
		lowbp = 0;
		highbp = KDB_MAXBPT;
	} else {
		diag = kdbgetularg(argv[1], &addr);
		if (diag)
			return diag;

		/*
		 * For addresses less than the maximum breakpoint number,
		 * assume that the breakpoint number is desired.
		 */
		if (addr < KDB_MAXBPT) {
			bp = &kdb_breakpoints[addr];
			lowbp = highbp = addr;
			highbp++;
		} else {
			for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT;
			    i++, bp++) {
				if (bp->bp_addr == addr) {
					lowbp = highbp = i;
					highbp++;
					break;
				}
			}
		}
	}

	/*
	 * Now operate on the set of breakpoints matching the input
	 * criteria (either '*' for all, or an individual breakpoint).
	 */
	for (bp = &kdb_breakpoints[lowbp], i = lowbp;
	    i < highbp;
	    i++, bp++) {
		if (bp->bp_free)
			continue;

		done++;

		switch (cmd) {
		case KDBCMD_BC:
			bp->bp_enabled = 0;

			kdb_printf("Breakpoint %d at "
				   kdb_bfd_vma_fmt " cleared\n",
				   i, bp->bp_addr);

			bp->bp_addr = 0;
			bp->bp_free = 1;

			break;
		case KDBCMD_BE:
			bp->bp_enabled = 1;

			kdb_printf("Breakpoint %d at "
				   kdb_bfd_vma_fmt " enabled",
				   i, bp->bp_addr);

			kdb_printf("\n");
			break;
		case KDBCMD_BD:
			if (!bp->bp_enabled)
				break;

			bp->bp_enabled = 0;

			kdb_printf("Breakpoint %d at "
				   kdb_bfd_vma_fmt " disabled\n",
				   i, bp->bp_addr);

			break;
		}
		if (bp->bp_delay && (cmd == KDBCMD_BC || cmd == KDBCMD_BD)) {
			bp->bp_delay = 0;
			KDB_STATE_CLEAR(SSBPT);
		}
	}

	return (!done) ? KDB_BPTNOTFOUND : 0;
}

/*
 * kdb_ss
 *
 *	Process the 'ss' (Single Step) command.
 *
 *	ss
 *
 * Parameters:
 *	argc	Argument count
 *	argv	Argument vector
 * Outputs:
 *	None.
 * Returns:
 *	KDB_CMD_SS for success, a kdb error if failure.
 * Locking:
 *	None.
 * Remarks:
 *
 *	Set the arch specific option to trigger a debug trap after the next
 *	instruction.
 */

static int kdb_ss(int argc, const char **argv)
{
	if (argc != 0)
		return KDB_ARGCOUNT;
	/*
	 * Set trace flag and go.
	 */
	KDB_STATE_SET(DOING_SS);
	return KDB_CMD_SS;
}

/* Initialize the breakpoint table and register	breakpoint commands. */

void __init kdb_initbptab(void)
{
	int i;
	kdb_bp_t *bp;

	/*
	 * First time initialization.
	 */
	memset(&kdb_breakpoints, '\0', sizeof(kdb_breakpoints));

	for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++)
		bp->bp_free = 1;

	kdb_register_flags("bp", kdb_bp, "[<vaddr>]",
		"Set/Display breakpoints", 0,
		KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS);
	kdb_register_flags("bl", kdb_bp, "[<vaddr>]",
		"Display breakpoints", 0,
		KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS);
	if (arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT)
		kdb_register_flags("bph", kdb_bp, "[<vaddr>]",
		"[datar [length]|dataw [length]]   Set hw brk", 0,
		KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS);
	kdb_register_flags("bc", kdb_bc, "<bpnum>",
		"Clear Breakpoint", 0,
		KDB_ENABLE_FLOW_CTRL);
	kdb_register_flags("be", kdb_bc, "<bpnum>",
		"Enable Breakpoint", 0,
		KDB_ENABLE_FLOW_CTRL);
	kdb_register_flags("bd", kdb_bc, "<bpnum>",
		"Disable Breakpoint", 0,
		KDB_ENABLE_FLOW_CTRL);

	kdb_register_flags("ss", kdb_ss, "",
		"Single Step", 1,
		KDB_ENABLE_FLOW_CTRL | KDB_REPEAT_NO_ARGS);
	/*
	 * Architecture dependent initialization.
	 */
}