aboutsummaryrefslogtreecommitdiff
path: root/arch/s390/kernel/ptrace.c
blob: cc02232aa96e93be846ceac801908fc08e070432 (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
/*
 *  arch/s390/kernel/ptrace.c
 *
 *  S390 version
 *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
 *               Martin Schwidefsky (schwidefsky@de.ibm.com)
 *
 *  Based on PowerPC version 
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  Derived from "arch/m68k/kernel/ptrace.c"
 *  Copyright (C) 1994 by Hamish Macdonald
 *  Taken from linux/kernel/ptrace.c and modified for M680x0.
 *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
 *
 * Modified by Cort Dougan (cort@cs.nmt.edu) 
 *
 *
 * This file is subject to the terms and conditions of the GNU General
 * Public License.  See the file README.legal in the main directory of
 * this archive for more details.
 */

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/security.h>
#include <linux/audit.h>
#include <linux/signal.h>

#include <asm/segment.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>

#ifdef CONFIG_COMPAT
#include "compat_ptrace.h"
#endif

static void
FixPerRegisters(struct task_struct *task)
{
	struct pt_regs *regs;
	per_struct *per_info;

	regs = __KSTK_PTREGS(task);
	per_info = (per_struct *) &task->thread.per_info;
	per_info->control_regs.bits.em_instruction_fetch =
		per_info->single_step | per_info->instruction_fetch;
	
	if (per_info->single_step) {
		per_info->control_regs.bits.starting_addr = 0;
#ifdef CONFIG_COMPAT
		if (test_thread_flag(TIF_31BIT))
			per_info->control_regs.bits.ending_addr = 0x7fffffffUL;
		else
#endif
			per_info->control_regs.bits.ending_addr = PSW_ADDR_INSN;
	} else {
		per_info->control_regs.bits.starting_addr =
			per_info->starting_addr;
		per_info->control_regs.bits.ending_addr =
			per_info->ending_addr;
	}
	/*
	 * if any of the control reg tracing bits are on 
	 * we switch on per in the psw
	 */
	if (per_info->control_regs.words.cr[0] & PER_EM_MASK)
		regs->psw.mask |= PSW_MASK_PER;
	else
		regs->psw.mask &= ~PSW_MASK_PER;

	if (per_info->control_regs.bits.em_storage_alteration)
		per_info->control_regs.bits.storage_alt_space_ctl = 1;
	else
		per_info->control_regs.bits.storage_alt_space_ctl = 0;
}

void
set_single_step(struct task_struct *task)
{
	task->thread.per_info.single_step = 1;
	FixPerRegisters(task);
}

void
clear_single_step(struct task_struct *task)
{
	task->thread.per_info.single_step = 0;
	FixPerRegisters(task);
}

/*
 * Called by kernel/ptrace.c when detaching..
 *
 * Make sure single step bits etc are not set.
 */
void
ptrace_disable(struct task_struct *child)
{
	/* make sure the single step bit is not set. */
	clear_single_step(child);
}

#ifndef CONFIG_64BIT
# define __ADDR_MASK 3
#else
# define __ADDR_MASK 7
#endif

/*
 * Read the word at offset addr from the user area of a process. The
 * trouble here is that the information is littered over different
 * locations. The process registers are found on the kernel stack,
 * the floating point stuff and the trace settings are stored in
 * the task structure. In addition the different structures in
 * struct user contain pad bytes that should be read as zeroes.
 * Lovely...
 */
static int
peek_user(struct task_struct *child, addr_t addr, addr_t data)
{
	struct user *dummy = NULL;
	addr_t offset, tmp, mask;

	/*
	 * Stupid gdb peeks/pokes the access registers in 64 bit with
	 * an alignment of 4. Programmers from hell...
	 */
	mask = __ADDR_MASK;
#ifdef CONFIG_64BIT
	if (addr >= (addr_t) &dummy->regs.acrs &&
	    addr < (addr_t) &dummy->regs.orig_gpr2)
		mask = 3;
#endif
	if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
		return -EIO;

	if (addr < (addr_t) &dummy->regs.acrs) {
		/*
		 * psw and gprs are stored on the stack
		 */
		tmp = *(addr_t *)((addr_t) &__KSTK_PTREGS(child)->psw + addr);
		if (addr == (addr_t) &dummy->regs.psw.mask)
			/* Remove per bit from user psw. */
			tmp &= ~PSW_MASK_PER;

	} else if (addr < (addr_t) &dummy->regs.orig_gpr2) {
		/*
		 * access registers are stored in the thread structure
		 */
		offset = addr - (addr_t) &dummy->regs.acrs;
#ifdef CONFIG_64BIT
		/*
		 * Very special case: old & broken 64 bit gdb reading
		 * from acrs[15]. Result is a 64 bit value. Read the
		 * 32 bit acrs[15] value and shift it by 32. Sick...
		 */
		if (addr == (addr_t) &dummy->regs.acrs[15])
			tmp = ((unsigned long) child->thread.acrs[15]) << 32;
		else
#endif
		tmp = *(addr_t *)((addr_t) &child->thread.acrs + offset);

	} else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
		/*
		 * orig_gpr2 is stored on the kernel stack
		 */
		tmp = (addr_t) __KSTK_PTREGS(child)->orig_gpr2;

	} else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
		/* 
		 * floating point regs. are stored in the thread structure
		 */
		offset = addr - (addr_t) &dummy->regs.fp_regs;
		tmp = *(addr_t *)((addr_t) &child->thread.fp_regs + offset);
		if (addr == (addr_t) &dummy->regs.fp_regs.fpc)
			tmp &= (unsigned long) FPC_VALID_MASK
				<< (BITS_PER_LONG - 32);

	} else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
		/*
		 * per_info is found in the thread structure
		 */
		offset = addr - (addr_t) &dummy->regs.per_info;
		tmp = *(addr_t *)((addr_t) &child->thread.per_info + offset);

	} else
		tmp = 0;

	return put_user(tmp, (addr_t __user *) data);
}

/*
 * Write a word to the user area of a process at location addr. This
 * operation does have an additional problem compared to peek_user.
 * Stores to the program status word and on the floating point
 * control register needs to get checked for validity.
 */
static int
poke_user(struct task_struct *child, addr_t addr, addr_t data)
{
	struct user *dummy = NULL;
	addr_t offset, mask;

	/*
	 * Stupid gdb peeks/pokes the access registers in 64 bit with
	 * an alignment of 4. Programmers from hell indeed...
	 */
	mask = __ADDR_MASK;
#ifdef CONFIG_64BIT
	if (addr >= (addr_t) &dummy->regs.acrs &&
	    addr < (addr_t) &dummy->regs.orig_gpr2)
		mask = 3;
#endif
	if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
		return -EIO;

	if (addr < (addr_t) &dummy->regs.acrs) {
		/*
		 * psw and gprs are stored on the stack
		 */
		if (addr == (addr_t) &dummy->regs.psw.mask &&
#ifdef CONFIG_COMPAT
		    data != PSW_MASK_MERGE(PSW_USER32_BITS, data) &&
#endif
		    data != PSW_MASK_MERGE(PSW_USER_BITS, data))
			/* Invalid psw mask. */
			return -EINVAL;
#ifndef CONFIG_64BIT
		if (addr == (addr_t) &dummy->regs.psw.addr)
			/* I'd like to reject addresses without the
			   high order bit but older gdb's rely on it */
			data |= PSW_ADDR_AMODE;
#endif
		*(addr_t *)((addr_t) &__KSTK_PTREGS(child)->psw + addr) = data;

	} else if (addr < (addr_t) (&dummy->regs.orig_gpr2)) {
		/*
		 * access registers are stored in the thread structure
		 */
		offset = addr - (addr_t) &dummy->regs.acrs;
#ifdef CONFIG_64BIT
		/*
		 * Very special case: old & broken 64 bit gdb writing
		 * to acrs[15] with a 64 bit value. Ignore the lower
		 * half of the value and write the upper 32 bit to
		 * acrs[15]. Sick...
		 */
		if (addr == (addr_t) &dummy->regs.acrs[15])
			child->thread.acrs[15] = (unsigned int) (data >> 32);
		else
#endif
		*(addr_t *)((addr_t) &child->thread.acrs + offset) = data;

	} else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
		/*
		 * orig_gpr2 is stored on the kernel stack
		 */
		__KSTK_PTREGS(child)->orig_gpr2 = data;

	} else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
		/*
		 * floating point regs. are stored in the thread structure
		 */
		if (addr == (addr_t) &dummy->regs.fp_regs.fpc &&
		    (data & ~((unsigned long) FPC_VALID_MASK
			      << (BITS_PER_LONG - 32))) != 0)
			return -EINVAL;
		offset = addr - (addr_t) &dummy->regs.fp_regs;
		*(addr_t *)((addr_t) &child->thread.fp_regs + offset) = data;

	} else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
		/*
		 * per_info is found in the thread structure 
		 */
		offset = addr - (addr_t) &dummy->regs.per_info;
		*(addr_t *)((addr_t) &child->thread.per_info + offset) = data;

	}

	FixPerRegisters(child);
	return 0;
}

static int
do_ptrace_normal(struct task_struct *child, long request, long addr, long data)
{
	unsigned long tmp;
	ptrace_area parea; 
	int copied, ret;

	switch (request) {
	case PTRACE_PEEKTEXT:
	case PTRACE_PEEKDATA:
		/* Remove high order bit from address (only for 31 bit). */
		addr &= PSW_ADDR_INSN;
		/* read word at location addr. */
		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
		if (copied != sizeof(tmp))
			return -EIO;
		return put_user(tmp, (unsigned long __user *) data);

	case PTRACE_PEEKUSR:
		/* read the word at location addr in the USER area. */
		return peek_user(child, addr, data);

	case PTRACE_POKETEXT:
	case PTRACE_POKEDATA:
		/* Remove high order bit from address (only for 31 bit). */
		addr &= PSW_ADDR_INSN;
		/* write the word at location addr. */
		copied = access_process_vm(child, addr, &data, sizeof(data),1);
		if (copied != sizeof(data))
			return -EIO;
		return 0;

	case PTRACE_POKEUSR:
		/* write the word at location addr in the USER area */
		return poke_user(child, addr, data);

	case PTRACE_PEEKUSR_AREA:
	case PTRACE_POKEUSR_AREA:
		if (copy_from_user(&parea, (void __user *) addr,
							sizeof(parea)))
			return -EFAULT;
		addr = parea.kernel_addr;
		data = parea.process_addr;
		copied = 0;
		while (copied < parea.len) {
			if (request == PTRACE_PEEKUSR_AREA)
				ret = peek_user(child, addr, data);
			else {
				addr_t tmp;
				if (get_user (tmp, (addr_t __user *) data))
					return -EFAULT;
				ret = poke_user(child, addr, tmp);
			}
			if (ret)
				return ret;
			addr += sizeof(unsigned long);
			data += sizeof(unsigned long);
			copied += sizeof(unsigned long);
		}
		return 0;
	}
	return ptrace_request(child, request, addr, data);
}

#ifdef CONFIG_COMPAT
/*
 * Now the fun part starts... a 31 bit program running in the
 * 31 bit emulation tracing another program. PTRACE_PEEKTEXT,
 * PTRACE_PEEKDATA, PTRACE_POKETEXT and PTRACE_POKEDATA are easy
 * to handle, the difference to the 64 bit versions of the requests
 * is that the access is done in multiples of 4 byte instead of
 * 8 bytes (sizeof(unsigned long) on 31/64 bit).
 * The ugly part are PTRACE_PEEKUSR, PTRACE_PEEKUSR_AREA,
 * PTRACE_POKEUSR and PTRACE_POKEUSR_AREA. If the traced program
 * is a 31 bit program too, the content of struct user can be
 * emulated. A 31 bit program peeking into the struct user of
 * a 64 bit program is a no-no.
 */

/*
 * Same as peek_user but for a 31 bit program.
 */
static int
peek_user_emu31(struct task_struct *child, addr_t addr, addr_t data)
{
	struct user32 *dummy32 = NULL;
	per_struct32 *dummy_per32 = NULL;
	addr_t offset;
	__u32 tmp;

	if (!test_thread_flag(TIF_31BIT) ||
	    (addr & 3) || addr > sizeof(struct user) - 3)
		return -EIO;

	if (addr < (addr_t) &dummy32->regs.acrs) {
		/*
		 * psw and gprs are stored on the stack
		 */
		if (addr == (addr_t) &dummy32->regs.psw.mask) {
			/* Fake a 31 bit psw mask. */
			tmp = (__u32)(__KSTK_PTREGS(child)->psw.mask >> 32);
			tmp = PSW32_MASK_MERGE(PSW32_USER_BITS, tmp);
		} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
			/* Fake a 31 bit psw address. */
			tmp = (__u32) __KSTK_PTREGS(child)->psw.addr |
				PSW32_ADDR_AMODE31;
		} else {
			/* gpr 0-15 */
			tmp = *(__u32 *)((addr_t) &__KSTK_PTREGS(child)->psw +
					 addr*2 + 4);
		}
	} else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
		/*
		 * access registers are stored in the thread structure
		 */
		offset = addr - (addr_t) &dummy32->regs.acrs;
		tmp = *(__u32*)((addr_t) &child->thread.acrs + offset);

	} else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
		/*
		 * orig_gpr2 is stored on the kernel stack
		 */
		tmp = *(__u32*)((addr_t) &__KSTK_PTREGS(child)->orig_gpr2 + 4);

	} else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
		/*
		 * floating point regs. are stored in the thread structure 
		 */
	        offset = addr - (addr_t) &dummy32->regs.fp_regs;
		tmp = *(__u32 *)((addr_t) &child->thread.fp_regs + offset);

	} else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
		/*
		 * per_info is found in the thread structure
		 */
		offset = addr - (addr_t) &dummy32->regs.per_info;
		/* This is magic. See per_struct and per_struct32. */
		if ((offset >= (addr_t) &dummy_per32->control_regs &&
		     offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
		    (offset >= (addr_t) &dummy_per32->starting_addr &&
		     offset <= (addr_t) &dummy_per32->ending_addr) ||
		    offset == (addr_t) &dummy_per32->lowcore.words.address)
			offset = offset*2 + 4;
		else
			offset = offset*2;
		tmp = *(__u32 *)((addr_t) &child->thread.per_info + offset);

	} else
		tmp = 0;

	return put_user(tmp, (__u32 __user *) data);
}

/*
 * Same as poke_user but for a 31 bit program.
 */
static int
poke_user_emu31(struct task_struct *child, addr_t addr, addr_t data)
{
	struct user32 *dummy32 = NULL;
	per_struct32 *dummy_per32 = NULL;
	addr_t offset;
	__u32 tmp;

	if (!test_thread_flag(TIF_31BIT) ||
	    (addr & 3) || addr > sizeof(struct user32) - 3)
		return -EIO;

	tmp = (__u32) data;

	if (addr < (addr_t) &dummy32->regs.acrs) {
		/*
		 * psw, gprs, acrs and orig_gpr2 are stored on the stack
		 */
		if (addr == (addr_t) &dummy32->regs.psw.mask) {
			/* Build a 64 bit psw mask from 31 bit mask. */
			if (tmp != PSW32_MASK_MERGE(PSW32_USER_BITS, tmp))
				/* Invalid psw mask. */
				return -EINVAL;
			__KSTK_PTREGS(child)->psw.mask =
				PSW_MASK_MERGE(PSW_USER32_BITS, (__u64) tmp << 32);
		} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
			/* Build a 64 bit psw address from 31 bit address. */
			__KSTK_PTREGS(child)->psw.addr = 
				(__u64) tmp & PSW32_ADDR_INSN;
		} else {
			/* gpr 0-15 */
			*(__u32*)((addr_t) &__KSTK_PTREGS(child)->psw
				  + addr*2 + 4) = tmp;
		}
	} else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
		/*
		 * access registers are stored in the thread structure
		 */
		offset = addr - (addr_t) &dummy32->regs.acrs;
		*(__u32*)((addr_t) &child->thread.acrs + offset) = tmp;

	} else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
		/*
		 * orig_gpr2 is stored on the kernel stack
		 */
		*(__u32*)((addr_t) &__KSTK_PTREGS(child)->orig_gpr2 + 4) = tmp;

	} else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
		/*
		 * floating point regs. are stored in the thread structure 
		 */
		if (addr == (addr_t) &dummy32->regs.fp_regs.fpc &&
		    (tmp & ~FPC_VALID_MASK) != 0)
			/* Invalid floating point control. */
			return -EINVAL;
	        offset = addr - (addr_t) &dummy32->regs.fp_regs;
		*(__u32 *)((addr_t) &child->thread.fp_regs + offset) = tmp;

	} else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
		/*
		 * per_info is found in the thread structure.
		 */
		offset = addr - (addr_t) &dummy32->regs.per_info;
		/*
		 * This is magic. See per_struct and per_struct32.
		 * By incident the offsets in per_struct are exactly
		 * twice the offsets in per_struct32 for all fields.
		 * The 8 byte fields need special handling though,
		 * because the second half (bytes 4-7) is needed and
		 * not the first half.
		 */
		if ((offset >= (addr_t) &dummy_per32->control_regs &&
		     offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
		    (offset >= (addr_t) &dummy_per32->starting_addr &&
		     offset <= (addr_t) &dummy_per32->ending_addr) ||
		    offset == (addr_t) &dummy_per32->lowcore.words.address)
			offset = offset*2 + 4;
		else
			offset = offset*2;
		*(__u32 *)((addr_t) &child->thread.per_info + offset) = tmp;

	}

	FixPerRegisters(child);
	return 0;
}

static int
do_ptrace_emu31(struct task_struct *child, long request, long addr, long data)
{
	unsigned int tmp;  /* 4 bytes !! */
	ptrace_area_emu31 parea; 
	int copied, ret;

	switch (request) {
	case PTRACE_PEEKTEXT:
	case PTRACE_PEEKDATA:
		/* read word at location addr. */
		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
		if (copied != sizeof(tmp))
			return -EIO;
		return put_user(tmp, (unsigned int __user *) data);

	case PTRACE_PEEKUSR:
		/* read the word at location addr in the USER area. */
		return peek_user_emu31(child, addr, data);

	case PTRACE_POKETEXT:
	case PTRACE_POKEDATA:
		/* write the word at location addr. */
		tmp = data;
		copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 1);
		if (copied != sizeof(tmp))
			return -EIO;
		return 0;

	case PTRACE_POKEUSR:
		/* write the word at location addr in the USER area */
		return poke_user_emu31(child, addr, data);

	case PTRACE_PEEKUSR_AREA:
	case PTRACE_POKEUSR_AREA:
		if (copy_from_user(&parea, (void __user *) addr,
							sizeof(parea)))
			return -EFAULT;
		addr = parea.kernel_addr;
		data = parea.process_addr;
		copied = 0;
		while (copied < parea.len) {
			if (request == PTRACE_PEEKUSR_AREA)
				ret = peek_user_emu31(child, addr, data);
			else {
				__u32 tmp;
				if (get_user (tmp, (__u32 __user *) data))
					return -EFAULT;
				ret = poke_user_emu31(child, addr, tmp);
			}
			if (ret)
				return ret;
			addr += sizeof(unsigned int);
			data += sizeof(unsigned int);
			copied += sizeof(unsigned int);
		}
		return 0;
	case PTRACE_GETEVENTMSG:
		return put_user((__u32) child->ptrace_message,
				(unsigned int __user *) data);
	case PTRACE_GETSIGINFO:
		if (child->last_siginfo == NULL)
			return -EINVAL;
		return copy_siginfo_to_user32((compat_siginfo_t __user *) data,
					      child->last_siginfo);
	case PTRACE_SETSIGINFO:
		if (child->last_siginfo == NULL)
			return -EINVAL;
		return copy_siginfo_from_user32(child->last_siginfo,
						(compat_siginfo_t __user *) data);
	}
	return ptrace_request(child, request, addr, data);
}
#endif

#define PT32_IEEE_IP 0x13c

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

	if (request == PTRACE_ATTACH)
		return ptrace_attach(child);

	/*
	 * Special cases to get/store the ieee instructions pointer.
	 */
	if (child == current) {
		if (request == PTRACE_PEEKUSR && addr == PT_IEEE_IP)
			return peek_user(child, addr, data);
		if (request == PTRACE_POKEUSR && addr == PT_IEEE_IP)
			return poke_user(child, addr, data);
#ifdef CONFIG_COMPAT
		if (request == PTRACE_PEEKUSR &&
		    addr == PT32_IEEE_IP && test_thread_flag(TIF_31BIT))
			return peek_user_emu31(child, addr, data);
		if (request == PTRACE_POKEUSR &&
		    addr == PT32_IEEE_IP && test_thread_flag(TIF_31BIT))
			return poke_user_emu31(child, addr, data);
#endif
	}

	ret = ptrace_check_attach(child, request == PTRACE_KILL);
	if (ret < 0)
		return ret;

	switch (request) {
	case PTRACE_SYSCALL:
		/* continue and stop at next (return from) syscall */
	case PTRACE_CONT:
		/* restart after signal. */
		if (!valid_signal(data))
			return -EIO;
		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;
		/* make sure the single step bit is not set. */
		clear_single_step(child);
		wake_up_process(child);
		return 0;

	case PTRACE_KILL:
		/*
		 * 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.
		 */
		if (child->exit_state == EXIT_ZOMBIE) /* already dead */
			return 0;
		child->exit_code = SIGKILL;
		/* make sure the single step bit is not set. */
		clear_single_step(child);
		wake_up_process(child);
		return 0;

	case PTRACE_SINGLESTEP:
		/* set the trap flag. */
		if (!valid_signal(data))
			return -EIO;
		clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
		child->exit_code = data;
		if (data)
			set_tsk_thread_flag(child, TIF_SINGLE_STEP);
		else
			set_single_step(child);
		/* give it a chance to run. */
		wake_up_process(child);
		return 0;

	case PTRACE_DETACH:
		/* detach a process that was attached. */
		return ptrace_detach(child, data);


	/* Do requests that differ for 31/64 bit */
	default:
#ifdef CONFIG_COMPAT
		if (test_thread_flag(TIF_31BIT))
			return do_ptrace_emu31(child, request, addr, data);
#endif
		return do_ptrace_normal(child, request, addr, data);
	}
	/* Not reached.  */
	return -EIO;
}

asmlinkage long
sys_ptrace(long request, long pid, long addr, long data)
{
	struct task_struct *child;
	int ret;

	lock_kernel();
	if (request == PTRACE_TRACEME) {
		 ret = ptrace_traceme();
		 goto out;
	}

	child = ptrace_get_task_struct(pid);
	if (IS_ERR(child)) {
		ret = PTR_ERR(child);
		goto out;
	}

	ret = do_ptrace(child, request, addr, data);
	put_task_struct(child);
out:
	unlock_kernel();
	return ret;
}

asmlinkage void
syscall_trace(struct pt_regs *regs, int entryexit)
{
	if (unlikely(current->audit_context) && entryexit)
		audit_syscall_exit(current, AUDITSC_RESULT(regs->gprs[2]), regs->gprs[2]);

	if (!test_thread_flag(TIF_SYSCALL_TRACE))
		goto out;
	if (!(current->ptrace & PT_PTRACED))
		goto out;
	ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
				 ? 0x80 : 0));

	/*
	 * If the debuffer has set an invalid system call number,
	 * we prepare to skip the system call restart handling.
	 */
	if (!entryexit && regs->gprs[2] >= NR_syscalls)
		regs->trap = -1;

	/*
	 * 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:
	if (unlikely(current->audit_context) && !entryexit)
		audit_syscall_entry(current, 
				    test_thread_flag(TIF_31BIT)?AUDIT_ARCH_S390:AUDIT_ARCH_S390X,
				    regs->gprs[2], regs->orig_gpr2, regs->gprs[3],
				    regs->gprs[4], regs->gprs[5]);
}