summaryrefslogtreecommitdiffstats
path: root/arch/tile/kernel/kgdb.c
blob: a506c2c28943715770ab43fa451797a8cb1566e4 (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
/*
 * Copyright 2013 Tilera Corporation. All Rights Reserved.
 *
 *   This program is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU General Public License
 *   as published by the Free Software Foundation, version 2.
 *
 *   This program is distributed in the hope that it will be useful, but
 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 *   NON INFRINGEMENT.  See the GNU General Public License for
 *   more details.
 *
 * TILE-Gx KGDB support.
 */

#include <linux/ptrace.h>
#include <linux/kgdb.h>
#include <linux/kdebug.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <asm/cacheflush.h>

static tile_bundle_bits singlestep_insn = TILEGX_BPT_BUNDLE | DIE_SSTEPBP;
static unsigned long stepped_addr;
static tile_bundle_bits stepped_instr;

struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = {
	{ "r0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[0])},
	{ "r1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[1])},
	{ "r2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[2])},
	{ "r3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[3])},
	{ "r4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[4])},
	{ "r5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[5])},
	{ "r6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[6])},
	{ "r7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[7])},
	{ "r8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[8])},
	{ "r9", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[9])},
	{ "r10", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[10])},
	{ "r11", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[11])},
	{ "r12", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[12])},
	{ "r13", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[13])},
	{ "r14", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[14])},
	{ "r15", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[15])},
	{ "r16", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[16])},
	{ "r17", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[17])},
	{ "r18", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[18])},
	{ "r19", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[19])},
	{ "r20", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[20])},
	{ "r21", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[21])},
	{ "r22", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[22])},
	{ "r23", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[23])},
	{ "r24", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[24])},
	{ "r25", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[25])},
	{ "r26", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[26])},
	{ "r27", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[27])},
	{ "r28", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[28])},
	{ "r29", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[29])},
	{ "r30", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[30])},
	{ "r31", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[31])},
	{ "r32", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[32])},
	{ "r33", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[33])},
	{ "r34", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[34])},
	{ "r35", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[35])},
	{ "r36", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[36])},
	{ "r37", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[37])},
	{ "r38", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[38])},
	{ "r39", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[39])},
	{ "r40", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[40])},
	{ "r41", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[41])},
	{ "r42", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[42])},
	{ "r43", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[43])},
	{ "r44", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[44])},
	{ "r45", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[45])},
	{ "r46", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[46])},
	{ "r47", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[47])},
	{ "r48", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[48])},
	{ "r49", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[49])},
	{ "r50", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[50])},
	{ "r51", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[51])},
	{ "r52", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[52])},
	{ "tp", GDB_SIZEOF_REG, offsetof(struct pt_regs, tp)},
	{ "sp", GDB_SIZEOF_REG, offsetof(struct pt_regs, sp)},
	{ "lr", GDB_SIZEOF_REG, offsetof(struct pt_regs, lr)},
	{ "sn", GDB_SIZEOF_REG, -1},
	{ "idn0", GDB_SIZEOF_REG, -1},
	{ "idn1", GDB_SIZEOF_REG, -1},
	{ "udn0", GDB_SIZEOF_REG, -1},
	{ "udn1", GDB_SIZEOF_REG, -1},
	{ "udn2", GDB_SIZEOF_REG, -1},
	{ "udn3", GDB_SIZEOF_REG, -1},
	{ "zero", GDB_SIZEOF_REG, -1},
	{ "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, pc)},
	{ "faultnum", GDB_SIZEOF_REG, offsetof(struct pt_regs, faultnum)},
};

char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
{
	if (regno >= DBG_MAX_REG_NUM || regno < 0)
		return NULL;

	if (dbg_reg_def[regno].offset != -1)
		memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
		       dbg_reg_def[regno].size);
	else
		memset(mem, 0, dbg_reg_def[regno].size);
	return dbg_reg_def[regno].name;
}

int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
{
	if (regno >= DBG_MAX_REG_NUM || regno < 0)
		return -EINVAL;

	if (dbg_reg_def[regno].offset != -1)
		memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
		       dbg_reg_def[regno].size);
	return 0;
}

/*
 * Similar to pt_regs_to_gdb_regs() except that process is sleeping and so
 * we may not be able to get all the info.
 */
void
sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
{
	struct pt_regs *thread_regs;

	if (task == NULL)
		return;

	/* Initialize to zero. */
	memset(gdb_regs, 0, NUMREGBYTES);

	thread_regs = task_pt_regs(task);
	memcpy(gdb_regs, thread_regs, TREG_LAST_GPR * sizeof(unsigned long));
	gdb_regs[TILEGX_PC_REGNUM] = thread_regs->pc;
	gdb_regs[TILEGX_FAULTNUM_REGNUM] = thread_regs->faultnum;
}

void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
{
	regs->pc = pc;
}

static void kgdb_call_nmi_hook(void *ignored)
{
	kgdb_nmicallback(raw_smp_processor_id(), NULL);
}

void kgdb_roundup_cpus(unsigned long flags)
{
	local_irq_enable();
	smp_call_function(kgdb_call_nmi_hook, NULL, 0);
	local_irq_disable();
}

/*
 * Convert a kernel address to the writable kernel text mapping.
 */
static unsigned long writable_address(unsigned long addr)
{
	unsigned long ret = 0;

	if (core_kernel_text(addr))
		ret = ktext_writable_addr(addr);
	else if (is_module_text_address(addr))
		ret = addr;
	else
		pr_err("Unknown virtual address 0x%lx\n", addr);

	return ret;
}

/*
 * Calculate the new address for after a step.
 */
static unsigned long get_step_address(struct pt_regs *regs)
{
	int src_reg;
	int jump_off;
	int br_off;
	unsigned long addr;
	unsigned int opcode;
	tile_bundle_bits bundle;

	/* Move to the next instruction by default. */
	addr = regs->pc + TILEGX_BUNDLE_SIZE_IN_BYTES;
	bundle = *(unsigned long *)instruction_pointer(regs);

	/* 0: X mode, Otherwise: Y mode. */
	if (bundle & TILEGX_BUNDLE_MODE_MASK) {
		if (get_Opcode_Y1(bundle) == RRR_1_OPCODE_Y1 &&
		    get_RRROpcodeExtension_Y1(bundle) ==
		    UNARY_RRR_1_OPCODE_Y1) {
			opcode = get_UnaryOpcodeExtension_Y1(bundle);

			switch (opcode) {
			case JALR_UNARY_OPCODE_Y1:
			case JALRP_UNARY_OPCODE_Y1:
			case JR_UNARY_OPCODE_Y1:
			case JRP_UNARY_OPCODE_Y1:
				src_reg = get_SrcA_Y1(bundle);
				dbg_get_reg(src_reg, &addr, regs);
				break;
			}
		}
	} else if (get_Opcode_X1(bundle) == RRR_0_OPCODE_X1) {
		if (get_RRROpcodeExtension_X1(bundle) ==
		    UNARY_RRR_0_OPCODE_X1) {
			opcode = get_UnaryOpcodeExtension_X1(bundle);

			switch (opcode) {
			case JALR_UNARY_OPCODE_X1:
			case JALRP_UNARY_OPCODE_X1:
			case JR_UNARY_OPCODE_X1:
			case JRP_UNARY_OPCODE_X1:
				src_reg = get_SrcA_X1(bundle);
				dbg_get_reg(src_reg, &addr, regs);
				break;
			}
		}
	} else if (get_Opcode_X1(bundle) == JUMP_OPCODE_X1) {
		opcode = get_JumpOpcodeExtension_X1(bundle);

		switch (opcode) {
		case JAL_JUMP_OPCODE_X1:
		case J_JUMP_OPCODE_X1:
			jump_off = sign_extend(get_JumpOff_X1(bundle), 27);
			addr = regs->pc +
				(jump_off << TILEGX_LOG2_BUNDLE_SIZE_IN_BYTES);
			break;
		}
	} else if (get_Opcode_X1(bundle) == BRANCH_OPCODE_X1) {
		br_off = 0;
		opcode = get_BrType_X1(bundle);

		switch (opcode) {
		case BEQZT_BRANCH_OPCODE_X1:
		case BEQZ_BRANCH_OPCODE_X1:
			if (get_SrcA_X1(bundle) == 0)
				br_off = get_BrOff_X1(bundle);
			break;
		case BGEZT_BRANCH_OPCODE_X1:
		case BGEZ_BRANCH_OPCODE_X1:
			if (get_SrcA_X1(bundle) >= 0)
				br_off = get_BrOff_X1(bundle);
			break;
		case BGTZT_BRANCH_OPCODE_X1:
		case BGTZ_BRANCH_OPCODE_X1:
			if (get_SrcA_X1(bundle) > 0)
				br_off = get_BrOff_X1(bundle);
			break;
		case BLBCT_BRANCH_OPCODE_X1:
		case BLBC_BRANCH_OPCODE_X1:
			if (!(get_SrcA_X1(bundle) & 1))
				br_off = get_BrOff_X1(bundle);
			break;
		case BLBST_BRANCH_OPCODE_X1:
		case BLBS_BRANCH_OPCODE_X1:
			if (get_SrcA_X1(bundle) & 1)
				br_off = get_BrOff_X1(bundle);
			break;
		case BLEZT_BRANCH_OPCODE_X1:
		case BLEZ_BRANCH_OPCODE_X1:
			if (get_SrcA_X1(bundle) <= 0)
				br_off = get_BrOff_X1(bundle);
			break;
		case BLTZT_BRANCH_OPCODE_X1:
		case BLTZ_BRANCH_OPCODE_X1:
			if (get_SrcA_X1(bundle) < 0)
				br_off = get_BrOff_X1(bundle);
			break;
		case BNEZT_BRANCH_OPCODE_X1:
		case BNEZ_BRANCH_OPCODE_X1:
			if (get_SrcA_X1(bundle) != 0)
				br_off = get_BrOff_X1(bundle);
			break;
		}

		if (br_off != 0) {
			br_off = sign_extend(br_off, 17);
			addr = regs->pc +
				(br_off << TILEGX_LOG2_BUNDLE_SIZE_IN_BYTES);
		}
	}

	return addr;
}

/*
 * Replace the next instruction after the current instruction with a
 * breakpoint instruction.
 */
static void do_single_step(struct pt_regs *regs)
{
	unsigned long addr_wr;

	/* Determine where the target instruction will send us to. */
	stepped_addr = get_step_address(regs);
	probe_kernel_read((char *)&stepped_instr, (char *)stepped_addr,
			  BREAK_INSTR_SIZE);

	addr_wr = writable_address(stepped_addr);
	probe_kernel_write((char *)addr_wr, (char *)&singlestep_insn,
			   BREAK_INSTR_SIZE);
	smp_wmb();
	flush_icache_range(stepped_addr, stepped_addr + BREAK_INSTR_SIZE);
}

static void undo_single_step(struct pt_regs *regs)
{
	unsigned long addr_wr;

	if (stepped_instr == 0)
		return;

	addr_wr = writable_address(stepped_addr);
	probe_kernel_write((char *)addr_wr, (char *)&stepped_instr,
			   BREAK_INSTR_SIZE);
	stepped_instr = 0;
	smp_wmb();
	flush_icache_range(stepped_addr, stepped_addr + BREAK_INSTR_SIZE);
}

/*
 * Calls linux_debug_hook before the kernel dies. If KGDB is enabled,
 * then try to fall into the debugger.
 */
static int
kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
{
	int ret;
	unsigned long flags;
	struct die_args *args = (struct die_args *)ptr;
	struct pt_regs *regs = args->regs;

#ifdef CONFIG_KPROBES
	/*
	 * Return immediately if the kprobes fault notifier has set
	 * DIE_PAGE_FAULT.
	 */
	if (cmd == DIE_PAGE_FAULT)
		return NOTIFY_DONE;
#endif /* CONFIG_KPROBES */

	switch (cmd) {
	case DIE_BREAK:
	case DIE_COMPILED_BPT:
		break;
	case DIE_SSTEPBP:
		local_irq_save(flags);
		kgdb_handle_exception(0, SIGTRAP, 0, regs);
		local_irq_restore(flags);
		return NOTIFY_STOP;
	default:
		/* Userspace events, ignore. */
		if (user_mode(regs))
			return NOTIFY_DONE;
	}

	local_irq_save(flags);
	ret = kgdb_handle_exception(args->trapnr, args->signr, args->err, regs);
	local_irq_restore(flags);
	if (ret)
		return NOTIFY_DONE;

	return NOTIFY_STOP;
}

static struct notifier_block kgdb_notifier = {
	.notifier_call = kgdb_notify,
};

/*
 * kgdb_arch_handle_exception - Handle architecture specific GDB packets.
 * @vector: The error vector of the exception that happened.
 * @signo: The signal number of the exception that happened.
 * @err_code: The error code of the exception that happened.
 * @remcom_in_buffer: The buffer of the packet we have read.
 * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
 * @regs: The &struct pt_regs of the current process.
 *
 * This function MUST handle the 'c' and 's' command packets,
 * as well packets to set / remove a hardware breakpoint, if used.
 * If there are additional packets which the hardware needs to handle,
 * they are handled here. The code should return -1 if it wants to
 * process more packets, and a %0 or %1 if it wants to exit from the
 * kgdb callback.
 */
int kgdb_arch_handle_exception(int vector, int signo, int err_code,
			       char *remcom_in_buffer, char *remcom_out_buffer,
			       struct pt_regs *regs)
{
	char *ptr;
	unsigned long address;

	/* Undo any stepping we may have done. */
	undo_single_step(regs);

	switch (remcom_in_buffer[0]) {
	case 'c':
	case 's':
	case 'D':
	case 'k':
		/*
		 * Try to read optional parameter, pc unchanged if no parm.
		 * If this was a compiled-in breakpoint, we need to move
		 * to the next instruction or we will just breakpoint
		 * over and over again.
		 */
		ptr = &remcom_in_buffer[1];
		if (kgdb_hex2long(&ptr, &address))
			regs->pc = address;
		else if (*(unsigned long *)regs->pc == compiled_bpt)
			regs->pc += BREAK_INSTR_SIZE;

		if (remcom_in_buffer[0] == 's') {
			do_single_step(regs);
			kgdb_single_step = 1;
			atomic_set(&kgdb_cpu_doing_single_step,
				   raw_smp_processor_id());
		} else
			atomic_set(&kgdb_cpu_doing_single_step, -1);

		return 0;
	}

	return -1; /* this means that we do not want to exit from the handler */
}

struct kgdb_arch arch_kgdb_ops;

/*
 * kgdb_arch_init - Perform any architecture specific initalization.
 *
 * This function will handle the initalization of any architecture
 * specific callbacks.
 */
int kgdb_arch_init(void)
{
	tile_bundle_bits bundle = TILEGX_BPT_BUNDLE;

	memcpy(arch_kgdb_ops.gdb_bpt_instr, &bundle, BREAK_INSTR_SIZE);
	return register_die_notifier(&kgdb_notifier);
}

/*
 * kgdb_arch_exit - Perform any architecture specific uninitalization.
 *
 * This function will handle the uninitalization of any architecture
 * specific callbacks, for dynamic registration and unregistration.
 */
void kgdb_arch_exit(void)
{
	unregister_die_notifier(&kgdb_notifier);
}

int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
{
	int err;
	unsigned long addr_wr = writable_address(bpt->bpt_addr);

	if (addr_wr == 0)
		return -1;

	err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
				BREAK_INSTR_SIZE);
	if (err)
		return err;

	err = probe_kernel_write((char *)addr_wr, arch_kgdb_ops.gdb_bpt_instr,
				 BREAK_INSTR_SIZE);
	smp_wmb();
	flush_icache_range((unsigned long)bpt->bpt_addr,
			   (unsigned long)bpt->bpt_addr + BREAK_INSTR_SIZE);
	return err;
}

int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
{
	int err;
	unsigned long addr_wr = writable_address(bpt->bpt_addr);

	if (addr_wr == 0)
		return -1;

	err = probe_kernel_write((char *)addr_wr, (char *)bpt->saved_instr,
				 BREAK_INSTR_SIZE);
	smp_wmb();
	flush_icache_range((unsigned long)bpt->bpt_addr,
			   (unsigned long)bpt->bpt_addr + BREAK_INSTR_SIZE);
	return err;
}