summaryrefslogtreecommitdiffstats
path: root/arch/m32r/kernel/ptrace.c
blob: 4c03361537aa6b49f3e2ba144afd667cd6b75307 (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
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
/*
 * linux/arch/m32r/kernel/ptrace.c
 *
 * Copyright (C) 2002  Hirokazu Takata, Takeo Takahashi
 * Copyright (C) 2004  Hirokazu Takata, Kei Sakamoto
 *
 * Original x86 implementation:
 *	By Ross Biro 1/23/92
 *	edited by Linus Torvalds
 *
 * Some code taken from sh version:
 *   Copyright (C) 1999, 2000  Kaz Kojima & Niibe Yutaka
 * Some code taken from arm version:
 *   Copyright (C) 2000 Russell King
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/err.h>
#include <linux/smp.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/string.h>
#include <linux/signal.h>

#include <asm/cacheflush.h>
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/mmu_context.h>

/*
 * This routine will get a word off of the process kernel stack.
 */
static inline unsigned long int
get_stack_long(struct task_struct *task, int offset)
{
	unsigned long *stack;

	stack = (unsigned long *)task_pt_regs(task);

	return stack[offset];
}

/*
 * This routine will put a word on the process kernel stack.
 */
static inline int
put_stack_long(struct task_struct *task, int offset, unsigned long data)
{
	unsigned long *stack;

	stack = (unsigned long *)task_pt_regs(task);
	stack[offset] = data;

	return 0;
}

static int reg_offset[] = {
	PT_R0, PT_R1, PT_R2, PT_R3, PT_R4, PT_R5, PT_R6, PT_R7,
	PT_R8, PT_R9, PT_R10, PT_R11, PT_R12, PT_FP, PT_LR, PT_SPU,
};

/*
 * Read the word at offset "off" into the "struct user".  We
 * actually access the pt_regs stored on the kernel stack.
 */
static int ptrace_read_user(struct task_struct *tsk, unsigned long off,
			    unsigned long __user *data)
{
	unsigned long tmp;
#ifndef NO_FPU
	struct user * dummy = NULL;
#endif

	if ((off & 3) || off > sizeof(struct user) - 3)
		return -EIO;

	off >>= 2;
	switch (off) {
	case PT_EVB:
		__asm__ __volatile__ (
			"mvfc	%0, cr5 \n\t"
	 		: "=r" (tmp)
		);
		break;
	case PT_CBR: {
			unsigned long psw;
			psw = get_stack_long(tsk, PT_PSW);
			tmp = ((psw >> 8) & 1);
		}
		break;
	case PT_PSW: {
			unsigned long psw, bbpsw;
			psw = get_stack_long(tsk, PT_PSW);
			bbpsw = get_stack_long(tsk, PT_BBPSW);
			tmp = ((psw >> 8) & 0xff) | ((bbpsw & 0xff) << 8);
		}
		break;
	case PT_PC:
		tmp = get_stack_long(tsk, PT_BPC);
		break;
	case PT_BPC:
		off = PT_BBPC;
		/* fall through */
	default:
		if (off < (sizeof(struct pt_regs) >> 2))
			tmp = get_stack_long(tsk, off);
#ifndef NO_FPU
		else if (off >= (long)(&dummy->fpu >> 2) &&
			 off < (long)(&dummy->u_fpvalid >> 2)) {
			if (!tsk_used_math(tsk)) {
				if (off == (long)(&dummy->fpu.fpscr >> 2))
					tmp = FPSCR_INIT;
				else
					tmp = 0;
			} else
				tmp = ((long *)(&tsk->thread.fpu >> 2))
					[off - (long)&dummy->fpu];
		} else if (off == (long)(&dummy->u_fpvalid >> 2))
			tmp = !!tsk_used_math(tsk);
#endif /* not NO_FPU */
		else
			tmp = 0;
	}

	return put_user(tmp, data);
}

static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
			     unsigned long data)
{
	int ret = -EIO;
#ifndef NO_FPU
	struct user * dummy = NULL;
#endif

	if ((off & 3) || off > sizeof(struct user) - 3)
		return -EIO;

	off >>= 2;
	switch (off) {
	case PT_EVB:
	case PT_BPC:
	case PT_SPI:
		/* We don't allow to modify evb. */
		ret = 0;
		break;
	case PT_PSW:
	case PT_CBR: {
			/* We allow to modify only cbr in psw */
			unsigned long psw;
			psw = get_stack_long(tsk, PT_PSW);
			psw = (psw & ~0x100) | ((data & 1) << 8);
			ret = put_stack_long(tsk, PT_PSW, psw);
		}
		break;
	case PT_PC:
		off = PT_BPC;
		data &= ~1;
		/* fall through */
	default:
		if (off < (sizeof(struct pt_regs) >> 2))
			ret = put_stack_long(tsk, off, data);
#ifndef NO_FPU
		else if (off >= (long)(&dummy->fpu >> 2) &&
			 off < (long)(&dummy->u_fpvalid >> 2)) {
			set_stopped_child_used_math(tsk);
			((long *)&tsk->thread.fpu)
				[off - (long)&dummy->fpu] = data;
			ret = 0;
		} else if (off == (long)(&dummy->u_fpvalid >> 2)) {
			conditional_stopped_child_used_math(data, tsk);
			ret = 0;
		}
#endif /* not NO_FPU */
		break;
	}

	return ret;
}

/*
 * Get all user integer registers.
 */
static int ptrace_getregs(struct task_struct *tsk, void __user *uregs)
{
	struct pt_regs *regs = task_pt_regs(tsk);

	return copy_to_user(uregs, regs, sizeof(struct pt_regs)) ? -EFAULT : 0;
}

/*
 * Set all user integer registers.
 */
static int ptrace_setregs(struct task_struct *tsk, void __user *uregs)
{
	struct pt_regs newregs;
	int ret;

	ret = -EFAULT;
	if (copy_from_user(&newregs, uregs, sizeof(struct pt_regs)) == 0) {
		struct pt_regs *regs = task_pt_regs(tsk);
		*regs = newregs;
		ret = 0;
	}

	return ret;
}


static inline int
check_condition_bit(struct task_struct *child)
{
	return (int)((get_stack_long(child, PT_PSW) >> 8) & 1);
}

static int
check_condition_src(unsigned long op, unsigned long regno1,
		    unsigned long regno2, struct task_struct *child)
{
	unsigned long reg1, reg2;

	reg2 = get_stack_long(child, reg_offset[regno2]);

	switch (op) {
	case 0x0: /* BEQ */
		reg1 = get_stack_long(child, reg_offset[regno1]);
		return reg1 == reg2;
	case 0x1: /* BNE */
		reg1 = get_stack_long(child, reg_offset[regno1]);
		return reg1 != reg2;
	case 0x8: /* BEQZ */
		return reg2 == 0;
	case 0x9: /* BNEZ */
		return reg2 != 0;
	case 0xa: /* BLTZ */
		return (int)reg2 < 0;
	case 0xb: /* BGEZ */
		return (int)reg2 >= 0;
	case 0xc: /* BLEZ */
		return (int)reg2 <= 0;
	case 0xd: /* BGTZ */
		return (int)reg2 > 0;
	default:
		/* never reached */
		return 0;
	}
}

static void
compute_next_pc_for_16bit_insn(unsigned long insn, unsigned long pc,
			       unsigned long *next_pc,
			       struct task_struct *child)
{
	unsigned long op, op2, op3;
	unsigned long disp;
	unsigned long regno;
	int parallel = 0;

	if (insn & 0x00008000)
		parallel = 1;
	if (pc & 3)
		insn &= 0x7fff;	/* right slot */
	else
		insn >>= 16;	/* left slot */

	op = (insn >> 12) & 0xf;
	op2 = (insn >> 8) & 0xf;
	op3 = (insn >> 4) & 0xf;

	if (op == 0x7) {
		switch (op2) {
		case 0xd: /* BNC */
		case 0x9: /* BNCL */
			if (!check_condition_bit(child)) {
				disp = (long)(insn << 24) >> 22;
				*next_pc = (pc & ~0x3) + disp;
				return;
			}
			break;
		case 0x8: /* BCL */
		case 0xc: /* BC */
			if (check_condition_bit(child)) {
				disp = (long)(insn << 24) >> 22;
				*next_pc = (pc & ~0x3) + disp;
				return;
			}
			break;
		case 0xe: /* BL */
		case 0xf: /* BRA */
			disp = (long)(insn << 24) >> 22;
			*next_pc = (pc & ~0x3) + disp;
			return;
			break;
		}
	} else if (op == 0x1) {
		switch (op2) {
		case 0x0:
			if (op3 == 0xf) { /* TRAP */
#if 1
				/* pass through */
#else
 				/* kernel space is not allowed as next_pc */
				unsigned long evb;
				unsigned long trapno;
				trapno = insn & 0xf;
				__asm__ __volatile__ (
					"mvfc %0, cr5\n"
		 			:"=r"(evb)
		 			:
				);
				*next_pc = evb + (trapno << 2);
				return;
#endif
			} else if (op3 == 0xd) { /* RTE */
				*next_pc = get_stack_long(child, PT_BPC);
				return;
			}
			break;
		case 0xc: /* JC */
			if (op3 == 0xc && check_condition_bit(child)) {
				regno = insn & 0xf;
				*next_pc = get_stack_long(child,
							  reg_offset[regno]);
				return;
			}
			break;
		case 0xd: /* JNC */
			if (op3 == 0xc && !check_condition_bit(child)) {
				regno = insn & 0xf;
				*next_pc = get_stack_long(child,
							  reg_offset[regno]);
				return;
			}
			break;
		case 0xe: /* JL */
		case 0xf: /* JMP */
			if (op3 == 0xc) { /* JMP */
				regno = insn & 0xf;
				*next_pc = get_stack_long(child,
							  reg_offset[regno]);
				return;
			}
			break;
		}
	}
	if (parallel)
		*next_pc = pc + 4;
	else
		*next_pc = pc + 2;
}

static void
compute_next_pc_for_32bit_insn(unsigned long insn, unsigned long pc,
			       unsigned long *next_pc,
			       struct task_struct *child)
{
	unsigned long op;
	unsigned long op2;
	unsigned long disp;
	unsigned long regno1, regno2;

	op = (insn >> 28) & 0xf;
	if (op == 0xf) { 	/* branch 24-bit relative */
		op2 = (insn >> 24) & 0xf;
		switch (op2) {
		case 0xd:	/* BNC */
		case 0x9:	/* BNCL */
			if (!check_condition_bit(child)) {
				disp = (long)(insn << 8) >> 6;
				*next_pc = (pc & ~0x3) + disp;
				return;
			}
			break;
		case 0x8:	/* BCL */
		case 0xc:	/* BC */
			if (check_condition_bit(child)) {
				disp = (long)(insn << 8) >> 6;
				*next_pc = (pc & ~0x3) + disp;
				return;
			}
			break;
		case 0xe:	/* BL */
		case 0xf:	/* BRA */
			disp = (long)(insn << 8) >> 6;
			*next_pc = (pc & ~0x3) + disp;
			return;
		}
	} else if (op == 0xb) { /* branch 16-bit relative */
		op2 = (insn >> 20) & 0xf;
		switch (op2) {
		case 0x0: /* BEQ */
		case 0x1: /* BNE */
		case 0x8: /* BEQZ */
		case 0x9: /* BNEZ */
		case 0xa: /* BLTZ */
		case 0xb: /* BGEZ */
		case 0xc: /* BLEZ */
		case 0xd: /* BGTZ */
			regno1 = ((insn >> 24) & 0xf);
			regno2 = ((insn >> 16) & 0xf);
			if (check_condition_src(op2, regno1, regno2, child)) {
				disp = (long)(insn << 16) >> 14;
				*next_pc = (pc & ~0x3) + disp;
				return;
			}
			break;
		}
	}
	*next_pc = pc + 4;
}

static inline void
compute_next_pc(unsigned long insn, unsigned long pc,
		unsigned long *next_pc, struct task_struct *child)
{
	if (insn & 0x80000000)
		compute_next_pc_for_32bit_insn(insn, pc, next_pc, child);
	else
		compute_next_pc_for_16bit_insn(insn, pc, next_pc, child);
}

static int
register_debug_trap(struct task_struct *child, unsigned long next_pc,
	unsigned long next_insn, unsigned long *code)
{
	struct debug_trap *p = &child->thread.debug_trap;
	unsigned long addr = next_pc & ~3;

	if (p->nr_trap == MAX_TRAPS) {
		printk("kernel BUG at %s %d: p->nr_trap = %d\n",
					__FILE__, __LINE__, p->nr_trap);
		return -1;
	}
	p->addr[p->nr_trap] = addr;
	p->insn[p->nr_trap] = next_insn;
	p->nr_trap++;
	if (next_pc & 3) {
		*code = (next_insn & 0xffff0000) | 0x10f1;
		/* xxx --> TRAP1 */
	} else {
		if ((next_insn & 0x80000000) || (next_insn & 0x8000)) {
			*code = 0x10f17000;
			/* TRAP1 --> NOP */
		} else {
			*code = (next_insn & 0xffff) | 0x10f10000;
			/* TRAP1 --> xxx */
		}
	}
	return 0;
}

static int
unregister_debug_trap(struct task_struct *child, unsigned long addr,
		      unsigned long *code)
{
	struct debug_trap *p = &child->thread.debug_trap;
        int i;

	/* Search debug trap entry. */
	for (i = 0; i < p->nr_trap; i++) {
		if (p->addr[i] == addr)
			break;
	}
	if (i >= p->nr_trap) {
		/* The trap may be requested from debugger.
		 * ptrace should do nothing in this case.
		 */
		return 0;
	}

	/* Recover original instruction code. */
	*code = p->insn[i];

	/* Shift debug trap entries. */
	while (i < p->nr_trap - 1) {
		p->insn[i] = p->insn[i + 1];
		p->addr[i] = p->addr[i + 1];
		i++;
	}
	p->nr_trap--;
	return 1;
}

static void
unregister_all_debug_traps(struct task_struct *child)
{
	struct debug_trap *p = &child->thread.debug_trap;
	int i;

	for (i = 0; i < p->nr_trap; i++)
		access_process_vm(child, p->addr[i], &p->insn[i], sizeof(p->insn[i]), 1);
	p->nr_trap = 0;
}

static inline void
invalidate_cache(void)
{
#if defined(CONFIG_CHIP_M32700) || defined(CONFIG_CHIP_OPSP)

	_flush_cache_copyback_all();

#else	/* ! CONFIG_CHIP_M32700 */

	/* Invalidate cache */
	__asm__ __volatile__ (
                "ldi    r0, #-1					\n\t"
                "ldi    r1, #0					\n\t"
                "stb    r1, @r0		; cache off		\n\t"
                ";						\n\t"
                "ldi    r0, #-2					\n\t"
                "ldi    r1, #1					\n\t"
                "stb    r1, @r0		; cache invalidate	\n\t"
                ".fillinsn					\n"
                "0:						\n\t"
                "ldb    r1, @r0		; invalidate check	\n\t"
                "bnez   r1, 0b					\n\t"
                ";						\n\t"
                "ldi    r0, #-1					\n\t"
                "ldi    r1, #1					\n\t"
                "stb    r1, @r0		; cache on		\n\t"
		: : : "r0", "r1", "memory"
	);
	/* FIXME: copying-back d-cache and invalidating i-cache are needed.
	 */
#endif	/* CONFIG_CHIP_M32700 */
}

/* Embed a debug trap (TRAP1) code */
static int
embed_debug_trap(struct task_struct *child, unsigned long next_pc)
{
	unsigned long next_insn, code;
	unsigned long addr = next_pc & ~3;

	if (access_process_vm(child, addr, &next_insn, sizeof(next_insn), 0)
	    != sizeof(next_insn)) {
		return -1; /* error */
	}

	/* Set a trap code. */
	if (register_debug_trap(child, next_pc, next_insn, &code)) {
		return -1; /* error */
	}
	if (access_process_vm(child, addr, &code, sizeof(code), 1)
	    != sizeof(code)) {
		return -1; /* error */
	}
	return 0; /* success */
}

void
withdraw_debug_trap(struct pt_regs *regs)
{
	unsigned long addr;
	unsigned long code;

 	addr = (regs->bpc - 2) & ~3;
	regs->bpc -= 2;
	if (unregister_debug_trap(current, addr, &code)) {
	    access_process_vm(current, addr, &code, sizeof(code), 1);
	    invalidate_cache();
	}
}

void
init_debug_traps(struct task_struct *child)
{
	struct debug_trap *p = &child->thread.debug_trap;
	int i;
	p->nr_trap = 0;
	for (i = 0; i < MAX_TRAPS; i++) {
		p->addr[i] = 0;
		p->insn[i] = 0;
	}
}

void user_enable_single_step(struct task_struct *child)
{
	unsigned long next_pc;
	unsigned long pc, insn;

	clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);

	/* Compute next pc.  */
	pc = get_stack_long(child, PT_BPC);

	if (access_process_vm(child, pc&~3, &insn, sizeof(insn), 0)
	    != sizeof(insn))
		return -EIO;

	compute_next_pc(insn, pc, &next_pc, child);
	if (next_pc & 0x80000000)
		return -EIO;

	if (embed_debug_trap(child, next_pc))
		return -EIO;

	invalidate_cache();
	return 0;
}

void user_disable_single_step(struct task_struct *child)
{
	unregister_all_debug_traps(child);
	invalidate_cache();
}

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Make sure single step bits etc are not set.
 */
void ptrace_disable(struct task_struct *child)
{
	/* nothing to do.. */
}

long
arch_ptrace(struct task_struct *child, long request,
	    unsigned long addr, unsigned long data)
{
	int ret;
	unsigned long __user *datap = (unsigned long __user *) data;

	switch (request) {
	/*
	 * read word at location "addr" in the child process.
	 */
	case PTRACE_PEEKTEXT:
	case PTRACE_PEEKDATA:
		ret = generic_ptrace_peekdata(child, addr, data);
		break;

	/*
	 * read the word at location addr in the USER area.
	 */
	case PTRACE_PEEKUSR:
		ret = ptrace_read_user(child, addr, datap);
		break;

	/*
	 * write the word at location addr.
	 */
	case PTRACE_POKETEXT:
	case PTRACE_POKEDATA:
		ret = generic_ptrace_pokedata(child, addr, data);
		if (ret == 0 && request == PTRACE_POKETEXT)
			invalidate_cache();
		break;

	/*
	 * write the word at location addr in the USER area.
	 */
	case PTRACE_POKEUSR:
		ret = ptrace_write_user(child, addr, data);
		break;

	case PTRACE_GETREGS:
		ret = ptrace_getregs(child, datap);
		break;

	case PTRACE_SETREGS:
		ret = ptrace_setregs(child, datap);
		break;

	default:
		ret = ptrace_request(child, request, addr, data);
		break;
	}

	return ret;
}

/* notification of system call entry/exit
 * - triggered by current->work.syscall_trace
 */
void do_syscall_trace(void)
{
	if (!test_thread_flag(TIF_SYSCALL_TRACE))
		return;
	if (!(current->ptrace & PT_PTRACED))
		return;
	/* the 0x80 provides a way for the tracing parent to distinguish
	   between a syscall stop and SIGTRAP delivery */
	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
				 ? 0x80 : 0));

	/*
	 * this isn't the same as continuing with a signal, but it will do
	 * for normal use.  strace only continues with a signal if the
	 * stopping signal is not SIGTRAP.  -brl
	 */
	if (current->exit_code) {
		send_sig(current->exit_code, current, 1);
		current->exit_code = 0;
	}
}