summaryrefslogtreecommitdiffstats
path: root/arch/arm/kernel/ptrace.c
blob: 5feee722ea9878e08a9f6415fe7de8e45d7595f9 (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
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
/*
 *  linux/arch/arm/kernel/ptrace.c
 *
 *  By Ross Biro 1/23/92
 * edited by Linus Torvalds
 * ARM modifications Copyright (C) 2000 Russell King
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/security.h>
#include <linux/init.h>
#include <linux/signal.h>

#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/system.h>
#include <asm/traps.h>

#include "ptrace.h"

#define REG_PC	15
#define REG_PSR	16
/*
 * does not yet catch signals sent when the child dies.
 * in exit.c or in signal.c.
 */

#if 0
/*
 * Breakpoint SWI instruction: SWI &9F0001
 */
#define BREAKINST_ARM	0xef9f0001
#define BREAKINST_THUMB	0xdf00		/* fill this in later */
#else
/*
 * New breakpoints - use an undefined instruction.  The ARM architecture
 * reference manual guarantees that the following instruction space
 * will produce an undefined instruction exception on all CPUs:
 *
 *  ARM:   xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx
 *  Thumb: 1101 1110 xxxx xxxx
 */
#define BREAKINST_ARM	0xe7f001f0
#define BREAKINST_THUMB	0xde01
#endif

/*
 * this routine will get a word off of the processes privileged stack.
 * the offset is how far from the base addr as stored in the THREAD.
 * this routine assumes that all the privileged stacks are in our
 * data space.
 */
static inline long get_user_reg(struct task_struct *task, int offset)
{
	return task_pt_regs(task)->uregs[offset];
}

/*
 * this routine will put a word on the processes privileged stack.
 * the offset is how far from the base addr as stored in the THREAD.
 * this routine assumes that all the privileged stacks are in our
 * data space.
 */
static inline int
put_user_reg(struct task_struct *task, int offset, long data)
{
	struct pt_regs newregs, *regs = task_pt_regs(task);
	int ret = -EINVAL;

	newregs = *regs;
	newregs.uregs[offset] = data;

	if (valid_user_regs(&newregs)) {
		regs->uregs[offset] = data;
		ret = 0;
	}

	return ret;
}

static inline int
read_u32(struct task_struct *task, unsigned long addr, u32 *res)
{
	int ret;

	ret = access_process_vm(task, addr, res, sizeof(*res), 0);

	return ret == sizeof(*res) ? 0 : -EIO;
}

static inline int
read_instr(struct task_struct *task, unsigned long addr, u32 *res)
{
	int ret;

	if (addr & 1) {
		u16 val;
		ret = access_process_vm(task, addr & ~1, &val, sizeof(val), 0);
		ret = ret == sizeof(val) ? 0 : -EIO;
		*res = val;
	} else {
		u32 val;
		ret = access_process_vm(task, addr & ~3, &val, sizeof(val), 0);
		ret = ret == sizeof(val) ? 0 : -EIO;
		*res = val;
	}
	return ret;
}

/*
 * Get value of register `rn' (in the instruction)
 */
static unsigned long
ptrace_getrn(struct task_struct *child, unsigned long insn)
{
	unsigned int reg = (insn >> 16) & 15;
	unsigned long val;

	val = get_user_reg(child, reg);
	if (reg == 15)
		val = pc_pointer(val + 8);

	return val;
}

/*
 * Get value of operand 2 (in an ALU instruction)
 */
static unsigned long
ptrace_getaluop2(struct task_struct *child, unsigned long insn)
{
	unsigned long val;
	int shift;
	int type;

	if (insn & 1 << 25) {
		val = insn & 255;
		shift = (insn >> 8) & 15;
		type = 3;
	} else {
		val = get_user_reg (child, insn & 15);

		if (insn & (1 << 4))
			shift = (int)get_user_reg (child, (insn >> 8) & 15);
		else
			shift = (insn >> 7) & 31;

		type = (insn >> 5) & 3;
	}

	switch (type) {
	case 0:	val <<= shift;	break;
	case 1:	val >>= shift;	break;
	case 2:
		val = (((signed long)val) >> shift);
		break;
	case 3:
 		val = (val >> shift) | (val << (32 - shift));
		break;
	}
	return val;
}

/*
 * Get value of operand 2 (in a LDR instruction)
 */
static unsigned long
ptrace_getldrop2(struct task_struct *child, unsigned long insn)
{
	unsigned long val;
	int shift;
	int type;

	val = get_user_reg(child, insn & 15);
	shift = (insn >> 7) & 31;
	type = (insn >> 5) & 3;

	switch (type) {
	case 0:	val <<= shift;	break;
	case 1:	val >>= shift;	break;
	case 2:
		val = (((signed long)val) >> shift);
		break;
	case 3:
 		val = (val >> shift) | (val << (32 - shift));
		break;
	}
	return val;
}

#define OP_MASK	0x01e00000
#define OP_AND	0x00000000
#define OP_EOR	0x00200000
#define OP_SUB	0x00400000
#define OP_RSB	0x00600000
#define OP_ADD	0x00800000
#define OP_ADC	0x00a00000
#define OP_SBC	0x00c00000
#define OP_RSC	0x00e00000
#define OP_ORR	0x01800000
#define OP_MOV	0x01a00000
#define OP_BIC	0x01c00000
#define OP_MVN	0x01e00000

static unsigned long
get_branch_address(struct task_struct *child, unsigned long pc, unsigned long insn)
{
	u32 alt = 0;

	switch (insn & 0x0e000000) {
	case 0x00000000:
	case 0x02000000: {
		/*
		 * data processing
		 */
		long aluop1, aluop2, ccbit;

	        if ((insn & 0x0fffffd0) == 0x012fff10) {
		        /*
			 * bx or blx
			 */
			alt = get_user_reg(child, insn & 15);
			break;
		}


		if ((insn & 0xf000) != 0xf000)
			break;

		aluop1 = ptrace_getrn(child, insn);
		aluop2 = ptrace_getaluop2(child, insn);
		ccbit  = get_user_reg(child, REG_PSR) & PSR_C_BIT ? 1 : 0;

		switch (insn & OP_MASK) {
		case OP_AND: alt = aluop1 & aluop2;		break;
		case OP_EOR: alt = aluop1 ^ aluop2;		break;
		case OP_SUB: alt = aluop1 - aluop2;		break;
		case OP_RSB: alt = aluop2 - aluop1;		break;
		case OP_ADD: alt = aluop1 + aluop2;		break;
		case OP_ADC: alt = aluop1 + aluop2 + ccbit;	break;
		case OP_SBC: alt = aluop1 - aluop2 + ccbit;	break;
		case OP_RSC: alt = aluop2 - aluop1 + ccbit;	break;
		case OP_ORR: alt = aluop1 | aluop2;		break;
		case OP_MOV: alt = aluop2;			break;
		case OP_BIC: alt = aluop1 & ~aluop2;		break;
		case OP_MVN: alt = ~aluop2;			break;
		}
		break;
	}

	case 0x04000000:
	case 0x06000000:
		/*
		 * ldr
		 */
		if ((insn & 0x0010f000) == 0x0010f000) {
			unsigned long base;

			base = ptrace_getrn(child, insn);
			if (insn & 1 << 24) {
				long aluop2;

				if (insn & 0x02000000)
					aluop2 = ptrace_getldrop2(child, insn);
				else
					aluop2 = insn & 0xfff;

				if (insn & 1 << 23)
					base += aluop2;
				else
					base -= aluop2;
			}
			if (read_u32(child, base, &alt) == 0)
				alt = pc_pointer(alt);
		}
		break;

	case 0x08000000:
		/*
		 * ldm
		 */
		if ((insn & 0x00108000) == 0x00108000) {
			unsigned long base;
			unsigned int nr_regs;

			if (insn & (1 << 23)) {
				nr_regs = hweight16(insn & 65535) << 2;

				if (!(insn & (1 << 24)))
					nr_regs -= 4;
			} else {
				if (insn & (1 << 24))
					nr_regs = -4;
				else
					nr_regs = 0;
			}

			base = ptrace_getrn(child, insn);

			if (read_u32(child, base + nr_regs, &alt) == 0)
				alt = pc_pointer(alt);
			break;
		}
		break;

	case 0x0a000000: {
		/*
		 * bl or b
		 */
		signed long displ;
		/* It's a branch/branch link: instead of trying to
		 * figure out whether the branch will be taken or not,
		 * we'll put a breakpoint at both locations.  This is
		 * simpler, more reliable, and probably not a whole lot
		 * slower than the alternative approach of emulating the
		 * branch.
		 */
		displ = (insn & 0x00ffffff) << 8;
		displ = (displ >> 6) + 8;
		if (displ != 0 && displ != 4)
			alt = pc + displ;
	    }
	    break;
	}

	return alt;
}

static int
swap_insn(struct task_struct *task, unsigned long addr,
	  void *old_insn, void *new_insn, int size)
{
	int ret;

	ret = access_process_vm(task, addr, old_insn, size, 0);
	if (ret == size)
		ret = access_process_vm(task, addr, new_insn, size, 1);
	return ret;
}

static void
add_breakpoint(struct task_struct *task, struct debug_info *dbg, unsigned long addr)
{
	int nr = dbg->nsaved;

	if (nr < 2) {
		u32 new_insn = BREAKINST_ARM;
		int res;

		res = swap_insn(task, addr, &dbg->bp[nr].insn, &new_insn, 4);

		if (res == 4) {
			dbg->bp[nr].address = addr;
			dbg->nsaved += 1;
		}
	} else
		printk(KERN_ERR "ptrace: too many breakpoints\n");
}

/*
 * Clear one breakpoint in the user program.  We copy what the hardware
 * does and use bit 0 of the address to indicate whether this is a Thumb
 * breakpoint or an ARM breakpoint.
 */
static void clear_breakpoint(struct task_struct *task, struct debug_entry *bp)
{
	unsigned long addr = bp->address;
	union debug_insn old_insn;
	int ret;

	if (addr & 1) {
		ret = swap_insn(task, addr & ~1, &old_insn.thumb,
				&bp->insn.thumb, 2);

		if (ret != 2 || old_insn.thumb != BREAKINST_THUMB)
			printk(KERN_ERR "%s:%d: corrupted Thumb breakpoint at "
				"0x%08lx (0x%04x)\n", task->comm, task->pid,
				addr, old_insn.thumb);
	} else {
		ret = swap_insn(task, addr & ~3, &old_insn.arm,
				&bp->insn.arm, 4);

		if (ret != 4 || old_insn.arm != BREAKINST_ARM)
			printk(KERN_ERR "%s:%d: corrupted ARM breakpoint at "
				"0x%08lx (0x%08x)\n", task->comm, task->pid,
				addr, old_insn.arm);
	}
}

void ptrace_set_bpt(struct task_struct *child)
{
	struct pt_regs *regs;
	unsigned long pc;
	u32 insn;
	int res;

	regs = task_pt_regs(child);
	pc = instruction_pointer(regs);

	if (thumb_mode(regs)) {
		printk(KERN_WARNING "ptrace: can't handle thumb mode\n");
		return;
	}

	res = read_instr(child, pc, &insn);
	if (!res) {
		struct debug_info *dbg = &child->thread.debug;
		unsigned long alt;

		dbg->nsaved = 0;

		alt = get_branch_address(child, pc, insn);
		if (alt)
			add_breakpoint(child, dbg, alt);

		/*
		 * Note that we ignore the result of setting the above
		 * breakpoint since it may fail.  When it does, this is
		 * not so much an error, but a forewarning that we may
		 * be receiving a prefetch abort shortly.
		 *
		 * If we don't set this breakpoint here, then we can
		 * lose control of the thread during single stepping.
		 */
		if (!alt || predicate(insn) != PREDICATE_ALWAYS)
			add_breakpoint(child, dbg, pc + 4);
	}
}

/*
 * Ensure no single-step breakpoint is pending.  Returns non-zero
 * value if child was being single-stepped.
 */
void ptrace_cancel_bpt(struct task_struct *child)
{
	int i, nsaved = child->thread.debug.nsaved;

	child->thread.debug.nsaved = 0;

	if (nsaved > 2) {
		printk("ptrace_cancel_bpt: bogus nsaved: %d!\n", nsaved);
		nsaved = 2;
	}

	for (i = 0; i < nsaved; i++)
		clear_breakpoint(child, &child->thread.debug.bp[i]);
}

/*
 * Called by kernel/ptrace.c when detaching..
 */
void ptrace_disable(struct task_struct *child)
{
	single_step_disable(child);
}

/*
 * Handle hitting a breakpoint.
 */
void ptrace_break(struct task_struct *tsk, struct pt_regs *regs)
{
	siginfo_t info;

	ptrace_cancel_bpt(tsk);

	info.si_signo = SIGTRAP;
	info.si_errno = 0;
	info.si_code  = TRAP_BRKPT;
	info.si_addr  = (void __user *)instruction_pointer(regs);

	force_sig_info(SIGTRAP, &info, tsk);
}

static int break_trap(struct pt_regs *regs, unsigned int instr)
{
	ptrace_break(current, regs);
	return 0;
}

static struct undef_hook arm_break_hook = {
	.instr_mask	= 0x0fffffff,
	.instr_val	= 0x07f001f0,
	.cpsr_mask	= PSR_T_BIT,
	.cpsr_val	= 0,
	.fn		= break_trap,
};

static struct undef_hook thumb_break_hook = {
	.instr_mask	= 0xffff,
	.instr_val	= 0xde01,
	.cpsr_mask	= PSR_T_BIT,
	.cpsr_val	= PSR_T_BIT,
	.fn		= break_trap,
};

static int __init ptrace_break_init(void)
{
	register_undef_hook(&arm_break_hook);
	register_undef_hook(&thumb_break_hook);
	return 0;
}

core_initcall(ptrace_break_init);

/*
 * 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 *ret)
{
	unsigned long tmp;

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

	tmp = 0;
	if (off < sizeof(struct pt_regs))
		tmp = get_user_reg(tsk, off >> 2);

	return put_user(tmp, ret);
}

/*
 * Write the word at offset "off" into "struct user".  We
 * actually access the pt_regs stored on the kernel stack.
 */
static int ptrace_write_user(struct task_struct *tsk, unsigned long off,
			     unsigned long val)
{
	if (off & 3 || off >= sizeof(struct user))
		return -EIO;

	if (off >= sizeof(struct pt_regs))
		return 0;

	return put_user_reg(tsk, off >> 2, val);
}

/*
 * 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);

		ret = -EINVAL;
		if (valid_user_regs(&newregs)) {
			*regs = newregs;
			ret = 0;
		}
	}

	return ret;
}

/*
 * Get the child FPU state.
 */
static int ptrace_getfpregs(struct task_struct *tsk, void __user *ufp)
{
	return copy_to_user(ufp, &task_thread_info(tsk)->fpstate,
			    sizeof(struct user_fp)) ? -EFAULT : 0;
}

/*
 * Set the child FPU state.
 */
static int ptrace_setfpregs(struct task_struct *tsk, void __user *ufp)
{
	struct thread_info *thread = task_thread_info(tsk);
	thread->used_cp[1] = thread->used_cp[2] = 1;
	return copy_from_user(&thread->fpstate, ufp,
			      sizeof(struct user_fp)) ? -EFAULT : 0;
}

#ifdef CONFIG_IWMMXT

/*
 * Get the child iWMMXt state.
 */
static int ptrace_getwmmxregs(struct task_struct *tsk, void __user *ufp)
{
	struct thread_info *thread = task_thread_info(tsk);

	if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
		return -ENODATA;
	iwmmxt_task_disable(thread);  /* force it to ram */
	return copy_to_user(ufp, &thread->fpstate.iwmmxt, IWMMXT_SIZE)
		? -EFAULT : 0;
}

/*
 * Set the child iWMMXt state.
 */
static int ptrace_setwmmxregs(struct task_struct *tsk, void __user *ufp)
{
	struct thread_info *thread = task_thread_info(tsk);

	if (!test_ti_thread_flag(thread, TIF_USING_IWMMXT))
		return -EACCES;
	iwmmxt_task_release(thread);  /* force a reload */
	return copy_from_user(&thread->fpstate.iwmmxt, ufp, IWMMXT_SIZE)
		? -EFAULT : 0;
}

#endif

#ifdef CONFIG_CRUNCH
/*
 * Get the child Crunch state.
 */
static int ptrace_getcrunchregs(struct task_struct *tsk, void __user *ufp)
{
	struct thread_info *thread = task_thread_info(tsk);

	crunch_task_disable(thread);  /* force it to ram */
	return copy_to_user(ufp, &thread->crunchstate, CRUNCH_SIZE)
		? -EFAULT : 0;
}

/*
 * Set the child Crunch state.
 */
static int ptrace_setcrunchregs(struct task_struct *tsk, void __user *ufp)
{
	struct thread_info *thread = task_thread_info(tsk);

	crunch_task_release(thread);  /* force a reload */
	return copy_from_user(&thread->crunchstate, ufp, CRUNCH_SIZE)
		? -EFAULT : 0;
}
#endif

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

	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;

		case PTRACE_PEEKUSR:
			ret = ptrace_read_user(child, addr, (unsigned long __user *)data);
			break;

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

		case PTRACE_POKEUSR:
			ret = ptrace_write_user(child, addr, data);
			break;

		/*
		 * continue/restart and stop at next (return from) syscall
		 */
		case PTRACE_SYSCALL:
		case PTRACE_CONT:
			ret = -EIO;
			if (!valid_signal(data))
				break;
			if (request == PTRACE_SYSCALL)
				set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
			else
				clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
			child->exit_code = data;
			single_step_disable(child);
			wake_up_process(child);
			ret = 0;
			break;

		/*
		 * make the child exit.  Best I can do is send it a sigkill.
		 * perhaps it should be put in the status that it wants to
		 * exit.
		 */
		case PTRACE_KILL:
			single_step_disable(child);
			if (child->exit_state != EXIT_ZOMBIE) {
				child->exit_code = SIGKILL;
				wake_up_process(child);
			}
			ret = 0;
			break;

		/*
		 * execute single instruction.
		 */
		case PTRACE_SINGLESTEP:
			ret = -EIO;
			if (!valid_signal(data))
				break;
			single_step_enable(child);
			clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
			child->exit_code = data;
			/* give it a chance to run. */
			wake_up_process(child);
			ret = 0;
			break;

		case PTRACE_GETREGS:
			ret = ptrace_getregs(child, (void __user *)data);
			break;

		case PTRACE_SETREGS:
			ret = ptrace_setregs(child, (void __user *)data);
			break;

		case PTRACE_GETFPREGS:
			ret = ptrace_getfpregs(child, (void __user *)data);
			break;
		
		case PTRACE_SETFPREGS:
			ret = ptrace_setfpregs(child, (void __user *)data);
			break;

#ifdef CONFIG_IWMMXT
		case PTRACE_GETWMMXREGS:
			ret = ptrace_getwmmxregs(child, (void __user *)data);
			break;

		case PTRACE_SETWMMXREGS:
			ret = ptrace_setwmmxregs(child, (void __user *)data);
			break;
#endif

		case PTRACE_GET_THREAD_AREA:
			ret = put_user(task_thread_info(child)->tp_value,
				       (unsigned long __user *) data);
			break;

		case PTRACE_SET_SYSCALL:
			task_thread_info(child)->syscall = data;
			ret = 0;
			break;

#ifdef CONFIG_CRUNCH
		case PTRACE_GETCRUNCHREGS:
			ret = ptrace_getcrunchregs(child, (void __user *)data);
			break;

		case PTRACE_SETCRUNCHREGS:
			ret = ptrace_setcrunchregs(child, (void __user *)data);
			break;
#endif

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

	return ret;
}

asmlinkage int syscall_trace(int why, struct pt_regs *regs, int scno)
{
	unsigned long ip;

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

	/*
	 * Save IP.  IP is used to denote syscall entry/exit:
	 *  IP = 0 -> entry, = 1 -> exit
	 */
	ip = regs->ARM_ip;
	regs->ARM_ip = why;

	current_thread_info()->syscall = scno;

	/* 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;
	}
	regs->ARM_ip = ip;

	return current_thread_info()->syscall;
}
OpenPOWER on IntegriCloud