summaryrefslogtreecommitdiffstats
path: root/arch/mips/kernel/ptrace.c
blob: 4812c6d916e4c5af7bf36f12aa7f1cdce4ad533f (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
/*
 * 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) 1992 Ross Biro
 * Copyright (C) Linus Torvalds
 * Copyright (C) 1994, 95, 96, 97, 98, 2000 Ralf Baechle
 * Copyright (C) 1996 David S. Miller
 * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
 * Copyright (C) 1999 MIPS Technologies, Inc.
 * Copyright (C) 2000 Ulf Carlsson
 *
 * At this time Linux/MIPS64 only supports syscall tracing, even for 32-bit
 * binaries.
 */
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/smp.h>
#include <linux/user.h>
#include <linux/security.h>
#include <linux/audit.h>
#include <linux/seccomp.h>

#include <asm/byteorder.h>
#include <asm/cpu.h>
#include <asm/dsp.h>
#include <asm/fpu.h>
#include <asm/mipsregs.h>
#include <asm/mipsmtregs.h>
#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/uaccess.h>
#include <asm/bootinfo.h>
#include <asm/reg.h>

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Make sure single step bits etc are not set.
 */
void ptrace_disable(struct task_struct *child)
{
	/* Don't load the watchpoint registers for the ex-child. */
	clear_tsk_thread_flag(child, TIF_LOAD_WATCH);
}

/*
 * Read a general register set.  We always use the 64-bit format, even
 * for 32-bit kernels and for 32-bit processes on a 64-bit kernel.
 * Registers are sign extended to fill the available space.
 */
int ptrace_getregs(struct task_struct *child, __s64 __user *data)
{
	struct pt_regs *regs;
	int i;

	if (!access_ok(VERIFY_WRITE, data, 38 * 8))
		return -EIO;

	regs = task_pt_regs(child);

	for (i = 0; i < 32; i++)
		__put_user((long)regs->regs[i], data + i);
	__put_user((long)regs->lo, data + EF_LO - EF_R0);
	__put_user((long)regs->hi, data + EF_HI - EF_R0);
	__put_user((long)regs->cp0_epc, data + EF_CP0_EPC - EF_R0);
	__put_user((long)regs->cp0_badvaddr, data + EF_CP0_BADVADDR - EF_R0);
	__put_user((long)regs->cp0_status, data + EF_CP0_STATUS - EF_R0);
	__put_user((long)regs->cp0_cause, data + EF_CP0_CAUSE - EF_R0);

	return 0;
}

/*
 * Write a general register set.  As for PTRACE_GETREGS, we always use
 * the 64-bit format.  On a 32-bit kernel only the lower order half
 * (according to endianness) will be used.
 */
int ptrace_setregs(struct task_struct *child, __s64 __user *data)
{
	struct pt_regs *regs;
	int i;

	if (!access_ok(VERIFY_READ, data, 38 * 8))
		return -EIO;

	regs = task_pt_regs(child);

	for (i = 0; i < 32; i++)
		__get_user(regs->regs[i], data + i);
	__get_user(regs->lo, data + EF_LO - EF_R0);
	__get_user(regs->hi, data + EF_HI - EF_R0);
	__get_user(regs->cp0_epc, data + EF_CP0_EPC - EF_R0);

	/* badvaddr, status, and cause may not be written.  */

	return 0;
}

int ptrace_getfpregs(struct task_struct *child, __u32 __user *data)
{
	int i;
	unsigned int tmp;

	if (!access_ok(VERIFY_WRITE, data, 33 * 8))
		return -EIO;

	if (tsk_used_math(child)) {
		fpureg_t *fregs = get_fpu_regs(child);
		for (i = 0; i < 32; i++)
			__put_user(fregs[i], i + (__u64 __user *) data);
	} else {
		for (i = 0; i < 32; i++)
			__put_user((__u64) -1, i + (__u64 __user *) data);
	}

	__put_user(child->thread.fpu.fcr31, data + 64);

	preempt_disable();
	if (cpu_has_fpu) {
		unsigned int flags;

		if (cpu_has_mipsmt) {
			unsigned int vpflags = dvpe();
			flags = read_c0_status();
			__enable_fpu();
			__asm__ __volatile__("cfc1\t%0,$0" : "=r" (tmp));
			write_c0_status(flags);
			evpe(vpflags);
		} else {
			flags = read_c0_status();
			__enable_fpu();
			__asm__ __volatile__("cfc1\t%0,$0" : "=r" (tmp));
			write_c0_status(flags);
		}
	} else {
		tmp = 0;
	}
	preempt_enable();
	__put_user(tmp, data + 65);

	return 0;
}

int ptrace_setfpregs(struct task_struct *child, __u32 __user *data)
{
	fpureg_t *fregs;
	int i;

	if (!access_ok(VERIFY_READ, data, 33 * 8))
		return -EIO;

	fregs = get_fpu_regs(child);

	for (i = 0; i < 32; i++)
		__get_user(fregs[i], i + (__u64 __user *) data);

	__get_user(child->thread.fpu.fcr31, data + 64);

	/* FIR may not be written.  */

	return 0;
}

int ptrace_get_watch_regs(struct task_struct *child,
			  struct pt_watch_regs __user *addr)
{
	enum pt_watch_style style;
	int i;

	if (!cpu_has_watch || current_cpu_data.watch_reg_use_cnt == 0)
		return -EIO;
	if (!access_ok(VERIFY_WRITE, addr, sizeof(struct pt_watch_regs)))
		return -EIO;

#ifdef CONFIG_32BIT
	style = pt_watch_style_mips32;
#define WATCH_STYLE mips32
#else
	style = pt_watch_style_mips64;
#define WATCH_STYLE mips64
#endif

	__put_user(style, &addr->style);
	__put_user(current_cpu_data.watch_reg_use_cnt,
		   &addr->WATCH_STYLE.num_valid);
	for (i = 0; i < current_cpu_data.watch_reg_use_cnt; i++) {
		__put_user(child->thread.watch.mips3264.watchlo[i],
			   &addr->WATCH_STYLE.watchlo[i]);
		__put_user(child->thread.watch.mips3264.watchhi[i] & 0xfff,
			   &addr->WATCH_STYLE.watchhi[i]);
		__put_user(current_cpu_data.watch_reg_masks[i],
			   &addr->WATCH_STYLE.watch_masks[i]);
	}
	for (; i < 8; i++) {
		__put_user(0, &addr->WATCH_STYLE.watchlo[i]);
		__put_user(0, &addr->WATCH_STYLE.watchhi[i]);
		__put_user(0, &addr->WATCH_STYLE.watch_masks[i]);
	}

	return 0;
}

int ptrace_set_watch_regs(struct task_struct *child,
			  struct pt_watch_regs __user *addr)
{
	int i;
	int watch_active = 0;
	unsigned long lt[NUM_WATCH_REGS];
	u16 ht[NUM_WATCH_REGS];

	if (!cpu_has_watch || current_cpu_data.watch_reg_use_cnt == 0)
		return -EIO;
	if (!access_ok(VERIFY_READ, addr, sizeof(struct pt_watch_regs)))
		return -EIO;
	/* Check the values. */
	for (i = 0; i < current_cpu_data.watch_reg_use_cnt; i++) {
		__get_user(lt[i], &addr->WATCH_STYLE.watchlo[i]);
#ifdef CONFIG_32BIT
		if (lt[i] & __UA_LIMIT)
			return -EINVAL;
#else
		if (test_tsk_thread_flag(child, TIF_32BIT_ADDR)) {
			if (lt[i] & 0xffffffff80000000UL)
				return -EINVAL;
		} else {
			if (lt[i] & __UA_LIMIT)
				return -EINVAL;
		}
#endif
		__get_user(ht[i], &addr->WATCH_STYLE.watchhi[i]);
		if (ht[i] & ~0xff8)
			return -EINVAL;
	}
	/* Install them. */
	for (i = 0; i < current_cpu_data.watch_reg_use_cnt; i++) {
		if (lt[i] & 7)
			watch_active = 1;
		child->thread.watch.mips3264.watchlo[i] = lt[i];
		/* Set the G bit. */
		child->thread.watch.mips3264.watchhi[i] = ht[i];
	}

	if (watch_active)
		set_tsk_thread_flag(child, TIF_LOAD_WATCH);
	else
		clear_tsk_thread_flag(child, TIF_LOAD_WATCH);

	return 0;
}

long arch_ptrace(struct task_struct *child, long request,
		 unsigned long addr, unsigned long data)
{
	int ret;
	void __user *addrp = (void __user *) addr;
	void __user *datavp = (void __user *) data;
	unsigned long __user *datalp = (void __user *) data;

	switch (request) {
	/* when I and D space are separate, these will need to be fixed. */
	case PTRACE_PEEKTEXT: /* read word at location addr. */
	case PTRACE_PEEKDATA:
		ret = generic_ptrace_peekdata(child, addr, data);
		break;

	/* Read the word at location addr in the USER area. */
	case PTRACE_PEEKUSR: {
		struct pt_regs *regs;
		unsigned long tmp = 0;

		regs = task_pt_regs(child);
		ret = 0;  /* Default return value. */

		switch (addr) {
		case 0 ... 31:
			tmp = regs->regs[addr];
			break;
		case FPR_BASE ... FPR_BASE + 31:
			if (tsk_used_math(child)) {
				fpureg_t *fregs = get_fpu_regs(child);

#ifdef CONFIG_32BIT
				/*
				 * The odd registers are actually the high
				 * order bits of the values stored in the even
				 * registers - unless we're using r2k_switch.S.
				 */
				if (addr & 1)
					tmp = (unsigned long) (fregs[((addr & ~1) - 32)] >> 32);
				else
					tmp = (unsigned long) (fregs[(addr - 32)] & 0xffffffff);
#endif
#ifdef CONFIG_64BIT
				tmp = fregs[addr - FPR_BASE];
#endif
			} else {
				tmp = -1;	/* FP not yet used  */
			}
			break;
		case PC:
			tmp = regs->cp0_epc;
			break;
		case CAUSE:
			tmp = regs->cp0_cause;
			break;
		case BADVADDR:
			tmp = regs->cp0_badvaddr;
			break;
		case MMHI:
			tmp = regs->hi;
			break;
		case MMLO:
			tmp = regs->lo;
			break;
#ifdef CONFIG_CPU_HAS_SMARTMIPS
		case ACX:
			tmp = regs->acx;
			break;
#endif
		case FPC_CSR:
			tmp = child->thread.fpu.fcr31;
			break;
		case FPC_EIR: {	/* implementation / version register */
			unsigned int flags;
#ifdef CONFIG_MIPS_MT_SMTC
			unsigned long irqflags;
			unsigned int mtflags;
#endif /* CONFIG_MIPS_MT_SMTC */

			preempt_disable();
			if (!cpu_has_fpu) {
				preempt_enable();
				break;
			}

#ifdef CONFIG_MIPS_MT_SMTC
			/* Read-modify-write of Status must be atomic */
			local_irq_save(irqflags);
			mtflags = dmt();
#endif /* CONFIG_MIPS_MT_SMTC */
			if (cpu_has_mipsmt) {
				unsigned int vpflags = dvpe();
				flags = read_c0_status();
				__enable_fpu();
				__asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
				write_c0_status(flags);
				evpe(vpflags);
			} else {
				flags = read_c0_status();
				__enable_fpu();
				__asm__ __volatile__("cfc1\t%0,$0": "=r" (tmp));
				write_c0_status(flags);
			}
#ifdef CONFIG_MIPS_MT_SMTC
			emt(mtflags);
			local_irq_restore(irqflags);
#endif /* CONFIG_MIPS_MT_SMTC */
			preempt_enable();
			break;
		}
		case DSP_BASE ... DSP_BASE + 5: {
			dspreg_t *dregs;

			if (!cpu_has_dsp) {
				tmp = 0;
				ret = -EIO;
				goto out;
			}
			dregs = __get_dsp_regs(child);
			tmp = (unsigned long) (dregs[addr - DSP_BASE]);
			break;
		}
		case DSP_CONTROL:
			if (!cpu_has_dsp) {
				tmp = 0;
				ret = -EIO;
				goto out;
			}
			tmp = child->thread.dsp.dspcontrol;
			break;
		default:
			tmp = 0;
			ret = -EIO;
			goto out;
		}
		ret = put_user(tmp, datalp);
		break;
	}

	/* when I and D space are separate, this will have to be fixed. */
	case PTRACE_POKETEXT: /* write the word at location addr. */
	case PTRACE_POKEDATA:
		ret = generic_ptrace_pokedata(child, addr, data);
		break;

	case PTRACE_POKEUSR: {
		struct pt_regs *regs;
		ret = 0;
		regs = task_pt_regs(child);

		switch (addr) {
		case 0 ... 31:
			regs->regs[addr] = data;
			break;
		case FPR_BASE ... FPR_BASE + 31: {
			fpureg_t *fregs = get_fpu_regs(child);

			if (!tsk_used_math(child)) {
				/* FP not yet used  */
				memset(&child->thread.fpu, ~0,
				       sizeof(child->thread.fpu));
				child->thread.fpu.fcr31 = 0;
			}
#ifdef CONFIG_32BIT
			/*
			 * The odd registers are actually the high order bits
			 * of the values stored in the even registers - unless
			 * we're using r2k_switch.S.
			 */
			if (addr & 1) {
				fregs[(addr & ~1) - FPR_BASE] &= 0xffffffff;
				fregs[(addr & ~1) - FPR_BASE] |= ((unsigned long long) data) << 32;
			} else {
				fregs[addr - FPR_BASE] &= ~0xffffffffLL;
				fregs[addr - FPR_BASE] |= data;
			}
#endif
#ifdef CONFIG_64BIT
			fregs[addr - FPR_BASE] = data;
#endif
			break;
		}
		case PC:
			regs->cp0_epc = data;
			break;
		case MMHI:
			regs->hi = data;
			break;
		case MMLO:
			regs->lo = data;
			break;
#ifdef CONFIG_CPU_HAS_SMARTMIPS
		case ACX:
			regs->acx = data;
			break;
#endif
		case FPC_CSR:
			child->thread.fpu.fcr31 = data;
			break;
		case DSP_BASE ... DSP_BASE + 5: {
			dspreg_t *dregs;

			if (!cpu_has_dsp) {
				ret = -EIO;
				break;
			}

			dregs = __get_dsp_regs(child);
			dregs[addr - DSP_BASE] = data;
			break;
		}
		case DSP_CONTROL:
			if (!cpu_has_dsp) {
				ret = -EIO;
				break;
			}
			child->thread.dsp.dspcontrol = data;
			break;
		default:
			/* The rest are not allowed. */
			ret = -EIO;
			break;
		}
		break;
		}

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

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

	case PTRACE_GETFPREGS:
		ret = ptrace_getfpregs(child, datavp);
		break;

	case PTRACE_SETFPREGS:
		ret = ptrace_setfpregs(child, datavp);
		break;

	case PTRACE_GET_THREAD_AREA:
		ret = put_user(task_thread_info(child)->tp_value, datalp);
		break;

	case PTRACE_GET_WATCH_REGS:
		ret = ptrace_get_watch_regs(child, addrp);
		break;

	case PTRACE_SET_WATCH_REGS:
		ret = ptrace_set_watch_regs(child, addrp);
		break;

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

static inline int audit_arch(void)
{
	int arch = EM_MIPS;
#ifdef CONFIG_64BIT
	arch |=  __AUDIT_ARCH_64BIT;
#endif
#if defined(__LITTLE_ENDIAN)
	arch |=  __AUDIT_ARCH_LE;
#endif
	return arch;
}

/*
 * Notification of system call entry/exit
 * - triggered by current->work.syscall_trace
 */
asmlinkage void syscall_trace_enter(struct pt_regs *regs)
{
	/* do the secure computing check first */
	secure_computing_strict(regs->regs[2]);

	if (!(current->ptrace & PT_PTRACED))
		goto out;

	if (!test_thread_flag(TIF_SYSCALL_TRACE))
		goto out;

	/* 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;
	}

out:
	audit_syscall_entry(audit_arch(), regs->regs[2],
			    regs->regs[4], regs->regs[5],
			    regs->regs[6], regs->regs[7]);
}

/*
 * Notification of system call entry/exit
 * - triggered by current->work.syscall_trace
 */
asmlinkage void syscall_trace_leave(struct pt_regs *regs)
{
	audit_syscall_exit(regs);

	if (!(current->ptrace & PT_PTRACED))
		return;

	if (!test_thread_flag(TIF_SYSCALL_TRACE))
		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;
	}
}