xref: /linux/arch/s390/kernel/ptrace.c (revision dfff0fa65ab15db45acd64b3189787d37ab163cd)
1 /*
2  *  arch/s390/kernel/ptrace.c
3  *
4  *  S390 version
5  *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
6  *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
7  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
8  *
9  *  Based on PowerPC version
10  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
11  *
12  *  Derived from "arch/m68k/kernel/ptrace.c"
13  *  Copyright (C) 1994 by Hamish Macdonald
14  *  Taken from linux/kernel/ptrace.c and modified for M680x0.
15  *  linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
16  *
17  * Modified by Cort Dougan (cort@cs.nmt.edu)
18  *
19  *
20  * This file is subject to the terms and conditions of the GNU General
21  * Public License.  See the file README.legal in the main directory of
22  * this archive for more details.
23  */
24 
25 #include <linux/kernel.h>
26 #include <linux/sched.h>
27 #include <linux/mm.h>
28 #include <linux/smp.h>
29 #include <linux/errno.h>
30 #include <linux/ptrace.h>
31 #include <linux/user.h>
32 #include <linux/security.h>
33 #include <linux/audit.h>
34 #include <linux/signal.h>
35 #include <linux/elf.h>
36 #include <linux/regset.h>
37 #include <linux/tracehook.h>
38 #include <linux/seccomp.h>
39 #include <trace/syscall.h>
40 #include <asm/compat.h>
41 #include <asm/segment.h>
42 #include <asm/page.h>
43 #include <asm/pgtable.h>
44 #include <asm/pgalloc.h>
45 #include <asm/system.h>
46 #include <asm/uaccess.h>
47 #include <asm/unistd.h>
48 #include "entry.h"
49 
50 #ifdef CONFIG_COMPAT
51 #include "compat_ptrace.h"
52 #endif
53 
54 enum s390_regset {
55 	REGSET_GENERAL,
56 	REGSET_FP,
57 };
58 
59 static void
60 FixPerRegisters(struct task_struct *task)
61 {
62 	struct pt_regs *regs;
63 	per_struct *per_info;
64 
65 	regs = task_pt_regs(task);
66 	per_info = (per_struct *) &task->thread.per_info;
67 	per_info->control_regs.bits.em_instruction_fetch =
68 		per_info->single_step | per_info->instruction_fetch;
69 
70 	if (per_info->single_step) {
71 		per_info->control_regs.bits.starting_addr = 0;
72 #ifdef CONFIG_COMPAT
73 		if (is_compat_task())
74 			per_info->control_regs.bits.ending_addr = 0x7fffffffUL;
75 		else
76 #endif
77 			per_info->control_regs.bits.ending_addr = PSW_ADDR_INSN;
78 	} else {
79 		per_info->control_regs.bits.starting_addr =
80 			per_info->starting_addr;
81 		per_info->control_regs.bits.ending_addr =
82 			per_info->ending_addr;
83 	}
84 	/*
85 	 * if any of the control reg tracing bits are on
86 	 * we switch on per in the psw
87 	 */
88 	if (per_info->control_regs.words.cr[0] & PER_EM_MASK)
89 		regs->psw.mask |= PSW_MASK_PER;
90 	else
91 		regs->psw.mask &= ~PSW_MASK_PER;
92 
93 	if (per_info->control_regs.bits.em_storage_alteration)
94 		per_info->control_regs.bits.storage_alt_space_ctl = 1;
95 	else
96 		per_info->control_regs.bits.storage_alt_space_ctl = 0;
97 }
98 
99 void user_enable_single_step(struct task_struct *task)
100 {
101 	task->thread.per_info.single_step = 1;
102 	FixPerRegisters(task);
103 }
104 
105 void user_disable_single_step(struct task_struct *task)
106 {
107 	task->thread.per_info.single_step = 0;
108 	FixPerRegisters(task);
109 }
110 
111 /*
112  * Called by kernel/ptrace.c when detaching..
113  *
114  * Make sure single step bits etc are not set.
115  */
116 void
117 ptrace_disable(struct task_struct *child)
118 {
119 	/* make sure the single step bit is not set. */
120 	user_disable_single_step(child);
121 }
122 
123 #ifndef CONFIG_64BIT
124 # define __ADDR_MASK 3
125 #else
126 # define __ADDR_MASK 7
127 #endif
128 
129 /*
130  * Read the word at offset addr from the user area of a process. The
131  * trouble here is that the information is littered over different
132  * locations. The process registers are found on the kernel stack,
133  * the floating point stuff and the trace settings are stored in
134  * the task structure. In addition the different structures in
135  * struct user contain pad bytes that should be read as zeroes.
136  * Lovely...
137  */
138 static unsigned long __peek_user(struct task_struct *child, addr_t addr)
139 {
140 	struct user *dummy = NULL;
141 	addr_t offset, tmp;
142 
143 	if (addr < (addr_t) &dummy->regs.acrs) {
144 		/*
145 		 * psw and gprs are stored on the stack
146 		 */
147 		tmp = *(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr);
148 		if (addr == (addr_t) &dummy->regs.psw.mask)
149 			/* Remove per bit from user psw. */
150 			tmp &= ~PSW_MASK_PER;
151 
152 	} else if (addr < (addr_t) &dummy->regs.orig_gpr2) {
153 		/*
154 		 * access registers are stored in the thread structure
155 		 */
156 		offset = addr - (addr_t) &dummy->regs.acrs;
157 #ifdef CONFIG_64BIT
158 		/*
159 		 * Very special case: old & broken 64 bit gdb reading
160 		 * from acrs[15]. Result is a 64 bit value. Read the
161 		 * 32 bit acrs[15] value and shift it by 32. Sick...
162 		 */
163 		if (addr == (addr_t) &dummy->regs.acrs[15])
164 			tmp = ((unsigned long) child->thread.acrs[15]) << 32;
165 		else
166 #endif
167 		tmp = *(addr_t *)((addr_t) &child->thread.acrs + offset);
168 
169 	} else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
170 		/*
171 		 * orig_gpr2 is stored on the kernel stack
172 		 */
173 		tmp = (addr_t) task_pt_regs(child)->orig_gpr2;
174 
175 	} else if (addr < (addr_t) &dummy->regs.fp_regs) {
176 		/*
177 		 * prevent reads of padding hole between
178 		 * orig_gpr2 and fp_regs on s390.
179 		 */
180 		tmp = 0;
181 
182 	} else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
183 		/*
184 		 * floating point regs. are stored in the thread structure
185 		 */
186 		offset = addr - (addr_t) &dummy->regs.fp_regs;
187 		tmp = *(addr_t *)((addr_t) &child->thread.fp_regs + offset);
188 		if (addr == (addr_t) &dummy->regs.fp_regs.fpc)
189 			tmp &= (unsigned long) FPC_VALID_MASK
190 				<< (BITS_PER_LONG - 32);
191 
192 	} else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
193 		/*
194 		 * per_info is found in the thread structure
195 		 */
196 		offset = addr - (addr_t) &dummy->regs.per_info;
197 		tmp = *(addr_t *)((addr_t) &child->thread.per_info + offset);
198 
199 	} else
200 		tmp = 0;
201 
202 	return tmp;
203 }
204 
205 static int
206 peek_user(struct task_struct *child, addr_t addr, addr_t data)
207 {
208 	addr_t tmp, mask;
209 
210 	/*
211 	 * Stupid gdb peeks/pokes the access registers in 64 bit with
212 	 * an alignment of 4. Programmers from hell...
213 	 */
214 	mask = __ADDR_MASK;
215 #ifdef CONFIG_64BIT
216 	if (addr >= (addr_t) &((struct user *) NULL)->regs.acrs &&
217 	    addr < (addr_t) &((struct user *) NULL)->regs.orig_gpr2)
218 		mask = 3;
219 #endif
220 	if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
221 		return -EIO;
222 
223 	tmp = __peek_user(child, addr);
224 	return put_user(tmp, (addr_t __user *) data);
225 }
226 
227 /*
228  * Write a word to the user area of a process at location addr. This
229  * operation does have an additional problem compared to peek_user.
230  * Stores to the program status word and on the floating point
231  * control register needs to get checked for validity.
232  */
233 static int __poke_user(struct task_struct *child, addr_t addr, addr_t data)
234 {
235 	struct user *dummy = NULL;
236 	addr_t offset;
237 
238 	if (addr < (addr_t) &dummy->regs.acrs) {
239 		/*
240 		 * psw and gprs are stored on the stack
241 		 */
242 		if (addr == (addr_t) &dummy->regs.psw.mask &&
243 #ifdef CONFIG_COMPAT
244 		    data != PSW_MASK_MERGE(psw_user32_bits, data) &&
245 #endif
246 		    data != PSW_MASK_MERGE(psw_user_bits, data))
247 			/* Invalid psw mask. */
248 			return -EINVAL;
249 #ifndef CONFIG_64BIT
250 		if (addr == (addr_t) &dummy->regs.psw.addr)
251 			/* I'd like to reject addresses without the
252 			   high order bit but older gdb's rely on it */
253 			data |= PSW_ADDR_AMODE;
254 #endif
255 		*(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr) = data;
256 
257 	} else if (addr < (addr_t) (&dummy->regs.orig_gpr2)) {
258 		/*
259 		 * access registers are stored in the thread structure
260 		 */
261 		offset = addr - (addr_t) &dummy->regs.acrs;
262 #ifdef CONFIG_64BIT
263 		/*
264 		 * Very special case: old & broken 64 bit gdb writing
265 		 * to acrs[15] with a 64 bit value. Ignore the lower
266 		 * half of the value and write the upper 32 bit to
267 		 * acrs[15]. Sick...
268 		 */
269 		if (addr == (addr_t) &dummy->regs.acrs[15])
270 			child->thread.acrs[15] = (unsigned int) (data >> 32);
271 		else
272 #endif
273 		*(addr_t *)((addr_t) &child->thread.acrs + offset) = data;
274 
275 	} else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
276 		/*
277 		 * orig_gpr2 is stored on the kernel stack
278 		 */
279 		task_pt_regs(child)->orig_gpr2 = data;
280 
281 	} else if (addr < (addr_t) &dummy->regs.fp_regs) {
282 		/*
283 		 * prevent writes of padding hole between
284 		 * orig_gpr2 and fp_regs on s390.
285 		 */
286 		return 0;
287 
288 	} else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
289 		/*
290 		 * floating point regs. are stored in the thread structure
291 		 */
292 		if (addr == (addr_t) &dummy->regs.fp_regs.fpc &&
293 		    (data & ~((unsigned long) FPC_VALID_MASK
294 			      << (BITS_PER_LONG - 32))) != 0)
295 			return -EINVAL;
296 		offset = addr - (addr_t) &dummy->regs.fp_regs;
297 		*(addr_t *)((addr_t) &child->thread.fp_regs + offset) = data;
298 
299 	} else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
300 		/*
301 		 * per_info is found in the thread structure
302 		 */
303 		offset = addr - (addr_t) &dummy->regs.per_info;
304 		*(addr_t *)((addr_t) &child->thread.per_info + offset) = data;
305 
306 	}
307 
308 	FixPerRegisters(child);
309 	return 0;
310 }
311 
312 static int
313 poke_user(struct task_struct *child, addr_t addr, addr_t data)
314 {
315 	addr_t mask;
316 
317 	/*
318 	 * Stupid gdb peeks/pokes the access registers in 64 bit with
319 	 * an alignment of 4. Programmers from hell indeed...
320 	 */
321 	mask = __ADDR_MASK;
322 #ifdef CONFIG_64BIT
323 	if (addr >= (addr_t) &((struct user *) NULL)->regs.acrs &&
324 	    addr < (addr_t) &((struct user *) NULL)->regs.orig_gpr2)
325 		mask = 3;
326 #endif
327 	if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
328 		return -EIO;
329 
330 	return __poke_user(child, addr, data);
331 }
332 
333 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
334 {
335 	ptrace_area parea;
336 	int copied, ret;
337 
338 	switch (request) {
339 	case PTRACE_PEEKTEXT:
340 	case PTRACE_PEEKDATA:
341 		/* Remove high order bit from address (only for 31 bit). */
342 		addr &= PSW_ADDR_INSN;
343 		/* read word at location addr. */
344 		return generic_ptrace_peekdata(child, addr, data);
345 
346 	case PTRACE_PEEKUSR:
347 		/* read the word at location addr in the USER area. */
348 		return peek_user(child, addr, data);
349 
350 	case PTRACE_POKETEXT:
351 	case PTRACE_POKEDATA:
352 		/* Remove high order bit from address (only for 31 bit). */
353 		addr &= PSW_ADDR_INSN;
354 		/* write the word at location addr. */
355 		return generic_ptrace_pokedata(child, addr, data);
356 
357 	case PTRACE_POKEUSR:
358 		/* write the word at location addr in the USER area */
359 		return poke_user(child, addr, data);
360 
361 	case PTRACE_PEEKUSR_AREA:
362 	case PTRACE_POKEUSR_AREA:
363 		if (copy_from_user(&parea, (void __force __user *) addr,
364 							sizeof(parea)))
365 			return -EFAULT;
366 		addr = parea.kernel_addr;
367 		data = parea.process_addr;
368 		copied = 0;
369 		while (copied < parea.len) {
370 			if (request == PTRACE_PEEKUSR_AREA)
371 				ret = peek_user(child, addr, data);
372 			else {
373 				addr_t utmp;
374 				if (get_user(utmp,
375 					     (addr_t __force __user *) data))
376 					return -EFAULT;
377 				ret = poke_user(child, addr, utmp);
378 			}
379 			if (ret)
380 				return ret;
381 			addr += sizeof(unsigned long);
382 			data += sizeof(unsigned long);
383 			copied += sizeof(unsigned long);
384 		}
385 		return 0;
386 	}
387 	return ptrace_request(child, request, addr, data);
388 }
389 
390 #ifdef CONFIG_COMPAT
391 /*
392  * Now the fun part starts... a 31 bit program running in the
393  * 31 bit emulation tracing another program. PTRACE_PEEKTEXT,
394  * PTRACE_PEEKDATA, PTRACE_POKETEXT and PTRACE_POKEDATA are easy
395  * to handle, the difference to the 64 bit versions of the requests
396  * is that the access is done in multiples of 4 byte instead of
397  * 8 bytes (sizeof(unsigned long) on 31/64 bit).
398  * The ugly part are PTRACE_PEEKUSR, PTRACE_PEEKUSR_AREA,
399  * PTRACE_POKEUSR and PTRACE_POKEUSR_AREA. If the traced program
400  * is a 31 bit program too, the content of struct user can be
401  * emulated. A 31 bit program peeking into the struct user of
402  * a 64 bit program is a no-no.
403  */
404 
405 /*
406  * Same as peek_user but for a 31 bit program.
407  */
408 static u32 __peek_user_compat(struct task_struct *child, addr_t addr)
409 {
410 	struct user32 *dummy32 = NULL;
411 	per_struct32 *dummy_per32 = NULL;
412 	addr_t offset;
413 	__u32 tmp;
414 
415 	if (addr < (addr_t) &dummy32->regs.acrs) {
416 		/*
417 		 * psw and gprs are stored on the stack
418 		 */
419 		if (addr == (addr_t) &dummy32->regs.psw.mask) {
420 			/* Fake a 31 bit psw mask. */
421 			tmp = (__u32)(task_pt_regs(child)->psw.mask >> 32);
422 			tmp = PSW32_MASK_MERGE(psw32_user_bits, tmp);
423 		} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
424 			/* Fake a 31 bit psw address. */
425 			tmp = (__u32) task_pt_regs(child)->psw.addr |
426 				PSW32_ADDR_AMODE31;
427 		} else {
428 			/* gpr 0-15 */
429 			tmp = *(__u32 *)((addr_t) &task_pt_regs(child)->psw +
430 					 addr*2 + 4);
431 		}
432 	} else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
433 		/*
434 		 * access registers are stored in the thread structure
435 		 */
436 		offset = addr - (addr_t) &dummy32->regs.acrs;
437 		tmp = *(__u32*)((addr_t) &child->thread.acrs + offset);
438 
439 	} else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
440 		/*
441 		 * orig_gpr2 is stored on the kernel stack
442 		 */
443 		tmp = *(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4);
444 
445 	} else if (addr < (addr_t) &dummy32->regs.fp_regs) {
446 		/*
447 		 * prevent reads of padding hole between
448 		 * orig_gpr2 and fp_regs on s390.
449 		 */
450 		tmp = 0;
451 
452 	} else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
453 		/*
454 		 * floating point regs. are stored in the thread structure
455 		 */
456 	        offset = addr - (addr_t) &dummy32->regs.fp_regs;
457 		tmp = *(__u32 *)((addr_t) &child->thread.fp_regs + offset);
458 
459 	} else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
460 		/*
461 		 * per_info is found in the thread structure
462 		 */
463 		offset = addr - (addr_t) &dummy32->regs.per_info;
464 		/* This is magic. See per_struct and per_struct32. */
465 		if ((offset >= (addr_t) &dummy_per32->control_regs &&
466 		     offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
467 		    (offset >= (addr_t) &dummy_per32->starting_addr &&
468 		     offset <= (addr_t) &dummy_per32->ending_addr) ||
469 		    offset == (addr_t) &dummy_per32->lowcore.words.address)
470 			offset = offset*2 + 4;
471 		else
472 			offset = offset*2;
473 		tmp = *(__u32 *)((addr_t) &child->thread.per_info + offset);
474 
475 	} else
476 		tmp = 0;
477 
478 	return tmp;
479 }
480 
481 static int peek_user_compat(struct task_struct *child,
482 			    addr_t addr, addr_t data)
483 {
484 	__u32 tmp;
485 
486 	if (!is_compat_task() || (addr & 3) || addr > sizeof(struct user) - 3)
487 		return -EIO;
488 
489 	tmp = __peek_user_compat(child, addr);
490 	return put_user(tmp, (__u32 __user *) data);
491 }
492 
493 /*
494  * Same as poke_user but for a 31 bit program.
495  */
496 static int __poke_user_compat(struct task_struct *child,
497 			      addr_t addr, addr_t data)
498 {
499 	struct user32 *dummy32 = NULL;
500 	per_struct32 *dummy_per32 = NULL;
501 	__u32 tmp = (__u32) data;
502 	addr_t offset;
503 
504 	if (addr < (addr_t) &dummy32->regs.acrs) {
505 		/*
506 		 * psw, gprs, acrs and orig_gpr2 are stored on the stack
507 		 */
508 		if (addr == (addr_t) &dummy32->regs.psw.mask) {
509 			/* Build a 64 bit psw mask from 31 bit mask. */
510 			if (tmp != PSW32_MASK_MERGE(psw32_user_bits, tmp))
511 				/* Invalid psw mask. */
512 				return -EINVAL;
513 			task_pt_regs(child)->psw.mask =
514 				PSW_MASK_MERGE(psw_user32_bits, (__u64) tmp << 32);
515 		} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
516 			/* Build a 64 bit psw address from 31 bit address. */
517 			task_pt_regs(child)->psw.addr =
518 				(__u64) tmp & PSW32_ADDR_INSN;
519 		} else {
520 			/* gpr 0-15 */
521 			*(__u32*)((addr_t) &task_pt_regs(child)->psw
522 				  + addr*2 + 4) = tmp;
523 		}
524 	} else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
525 		/*
526 		 * access registers are stored in the thread structure
527 		 */
528 		offset = addr - (addr_t) &dummy32->regs.acrs;
529 		*(__u32*)((addr_t) &child->thread.acrs + offset) = tmp;
530 
531 	} else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
532 		/*
533 		 * orig_gpr2 is stored on the kernel stack
534 		 */
535 		*(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4) = tmp;
536 
537 	} else if (addr < (addr_t) &dummy32->regs.fp_regs) {
538 		/*
539 		 * prevent writess of padding hole between
540 		 * orig_gpr2 and fp_regs on s390.
541 		 */
542 		return 0;
543 
544 	} else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
545 		/*
546 		 * floating point regs. are stored in the thread structure
547 		 */
548 		if (addr == (addr_t) &dummy32->regs.fp_regs.fpc &&
549 		    (tmp & ~FPC_VALID_MASK) != 0)
550 			/* Invalid floating point control. */
551 			return -EINVAL;
552 	        offset = addr - (addr_t) &dummy32->regs.fp_regs;
553 		*(__u32 *)((addr_t) &child->thread.fp_regs + offset) = tmp;
554 
555 	} else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
556 		/*
557 		 * per_info is found in the thread structure.
558 		 */
559 		offset = addr - (addr_t) &dummy32->regs.per_info;
560 		/*
561 		 * This is magic. See per_struct and per_struct32.
562 		 * By incident the offsets in per_struct are exactly
563 		 * twice the offsets in per_struct32 for all fields.
564 		 * The 8 byte fields need special handling though,
565 		 * because the second half (bytes 4-7) is needed and
566 		 * not the first half.
567 		 */
568 		if ((offset >= (addr_t) &dummy_per32->control_regs &&
569 		     offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
570 		    (offset >= (addr_t) &dummy_per32->starting_addr &&
571 		     offset <= (addr_t) &dummy_per32->ending_addr) ||
572 		    offset == (addr_t) &dummy_per32->lowcore.words.address)
573 			offset = offset*2 + 4;
574 		else
575 			offset = offset*2;
576 		*(__u32 *)((addr_t) &child->thread.per_info + offset) = tmp;
577 
578 	}
579 
580 	FixPerRegisters(child);
581 	return 0;
582 }
583 
584 static int poke_user_compat(struct task_struct *child,
585 			    addr_t addr, addr_t data)
586 {
587 	if (!is_compat_task() || (addr & 3) || addr > sizeof(struct user32) - 3)
588 		return -EIO;
589 
590 	return __poke_user_compat(child, addr, data);
591 }
592 
593 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
594 			compat_ulong_t caddr, compat_ulong_t cdata)
595 {
596 	unsigned long addr = caddr;
597 	unsigned long data = cdata;
598 	ptrace_area_emu31 parea;
599 	int copied, ret;
600 
601 	switch (request) {
602 	case PTRACE_PEEKUSR:
603 		/* read the word at location addr in the USER area. */
604 		return peek_user_compat(child, addr, data);
605 
606 	case PTRACE_POKEUSR:
607 		/* write the word at location addr in the USER area */
608 		return poke_user_compat(child, addr, data);
609 
610 	case PTRACE_PEEKUSR_AREA:
611 	case PTRACE_POKEUSR_AREA:
612 		if (copy_from_user(&parea, (void __force __user *) addr,
613 							sizeof(parea)))
614 			return -EFAULT;
615 		addr = parea.kernel_addr;
616 		data = parea.process_addr;
617 		copied = 0;
618 		while (copied < parea.len) {
619 			if (request == PTRACE_PEEKUSR_AREA)
620 				ret = peek_user_compat(child, addr, data);
621 			else {
622 				__u32 utmp;
623 				if (get_user(utmp,
624 					     (__u32 __force __user *) data))
625 					return -EFAULT;
626 				ret = poke_user_compat(child, addr, utmp);
627 			}
628 			if (ret)
629 				return ret;
630 			addr += sizeof(unsigned int);
631 			data += sizeof(unsigned int);
632 			copied += sizeof(unsigned int);
633 		}
634 		return 0;
635 	}
636 	return compat_ptrace_request(child, request, addr, data);
637 }
638 #endif
639 
640 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
641 {
642 	long ret;
643 
644 	/* Do the secure computing check first. */
645 	secure_computing(regs->gprs[2]);
646 
647 	/*
648 	 * The sysc_tracesys code in entry.S stored the system
649 	 * call number to gprs[2].
650 	 */
651 	ret = regs->gprs[2];
652 	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
653 	    (tracehook_report_syscall_entry(regs) ||
654 	     regs->gprs[2] >= NR_syscalls)) {
655 		/*
656 		 * Tracing decided this syscall should not happen or the
657 		 * debugger stored an invalid system call number. Skip
658 		 * the system call and the system call restart handling.
659 		 */
660 		regs->svcnr = 0;
661 		ret = -1;
662 	}
663 
664 	if (unlikely(test_thread_flag(TIF_SYSCALL_FTRACE)))
665 		ftrace_syscall_enter(regs);
666 
667 	if (unlikely(current->audit_context))
668 		audit_syscall_entry(is_compat_task() ?
669 					AUDIT_ARCH_S390 : AUDIT_ARCH_S390X,
670 				    regs->gprs[2], regs->orig_gpr2,
671 				    regs->gprs[3], regs->gprs[4],
672 				    regs->gprs[5]);
673 	return ret;
674 }
675 
676 asmlinkage void do_syscall_trace_exit(struct pt_regs *regs)
677 {
678 	if (unlikely(current->audit_context))
679 		audit_syscall_exit(AUDITSC_RESULT(regs->gprs[2]),
680 				   regs->gprs[2]);
681 
682 	if (unlikely(test_thread_flag(TIF_SYSCALL_FTRACE)))
683 		ftrace_syscall_exit(regs);
684 
685 	if (test_thread_flag(TIF_SYSCALL_TRACE))
686 		tracehook_report_syscall_exit(regs, 0);
687 }
688 
689 /*
690  * user_regset definitions.
691  */
692 
693 static int s390_regs_get(struct task_struct *target,
694 			 const struct user_regset *regset,
695 			 unsigned int pos, unsigned int count,
696 			 void *kbuf, void __user *ubuf)
697 {
698 	if (target == current)
699 		save_access_regs(target->thread.acrs);
700 
701 	if (kbuf) {
702 		unsigned long *k = kbuf;
703 		while (count > 0) {
704 			*k++ = __peek_user(target, pos);
705 			count -= sizeof(*k);
706 			pos += sizeof(*k);
707 		}
708 	} else {
709 		unsigned long __user *u = ubuf;
710 		while (count > 0) {
711 			if (__put_user(__peek_user(target, pos), u++))
712 				return -EFAULT;
713 			count -= sizeof(*u);
714 			pos += sizeof(*u);
715 		}
716 	}
717 	return 0;
718 }
719 
720 static int s390_regs_set(struct task_struct *target,
721 			 const struct user_regset *regset,
722 			 unsigned int pos, unsigned int count,
723 			 const void *kbuf, const void __user *ubuf)
724 {
725 	int rc = 0;
726 
727 	if (target == current)
728 		save_access_regs(target->thread.acrs);
729 
730 	if (kbuf) {
731 		const unsigned long *k = kbuf;
732 		while (count > 0 && !rc) {
733 			rc = __poke_user(target, pos, *k++);
734 			count -= sizeof(*k);
735 			pos += sizeof(*k);
736 		}
737 	} else {
738 		const unsigned long  __user *u = ubuf;
739 		while (count > 0 && !rc) {
740 			unsigned long word;
741 			rc = __get_user(word, u++);
742 			if (rc)
743 				break;
744 			rc = __poke_user(target, pos, word);
745 			count -= sizeof(*u);
746 			pos += sizeof(*u);
747 		}
748 	}
749 
750 	if (rc == 0 && target == current)
751 		restore_access_regs(target->thread.acrs);
752 
753 	return rc;
754 }
755 
756 static int s390_fpregs_get(struct task_struct *target,
757 			   const struct user_regset *regset, unsigned int pos,
758 			   unsigned int count, void *kbuf, void __user *ubuf)
759 {
760 	if (target == current)
761 		save_fp_regs(&target->thread.fp_regs);
762 
763 	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
764 				   &target->thread.fp_regs, 0, -1);
765 }
766 
767 static int s390_fpregs_set(struct task_struct *target,
768 			   const struct user_regset *regset, unsigned int pos,
769 			   unsigned int count, const void *kbuf,
770 			   const void __user *ubuf)
771 {
772 	int rc = 0;
773 
774 	if (target == current)
775 		save_fp_regs(&target->thread.fp_regs);
776 
777 	/* If setting FPC, must validate it first. */
778 	if (count > 0 && pos < offsetof(s390_fp_regs, fprs)) {
779 		u32 fpc[2] = { target->thread.fp_regs.fpc, 0 };
780 		rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &fpc,
781 					0, offsetof(s390_fp_regs, fprs));
782 		if (rc)
783 			return rc;
784 		if ((fpc[0] & ~FPC_VALID_MASK) != 0 || fpc[1] != 0)
785 			return -EINVAL;
786 		target->thread.fp_regs.fpc = fpc[0];
787 	}
788 
789 	if (rc == 0 && count > 0)
790 		rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
791 					target->thread.fp_regs.fprs,
792 					offsetof(s390_fp_regs, fprs), -1);
793 
794 	if (rc == 0 && target == current)
795 		restore_fp_regs(&target->thread.fp_regs);
796 
797 	return rc;
798 }
799 
800 static const struct user_regset s390_regsets[] = {
801 	[REGSET_GENERAL] = {
802 		.core_note_type = NT_PRSTATUS,
803 		.n = sizeof(s390_regs) / sizeof(long),
804 		.size = sizeof(long),
805 		.align = sizeof(long),
806 		.get = s390_regs_get,
807 		.set = s390_regs_set,
808 	},
809 	[REGSET_FP] = {
810 		.core_note_type = NT_PRFPREG,
811 		.n = sizeof(s390_fp_regs) / sizeof(long),
812 		.size = sizeof(long),
813 		.align = sizeof(long),
814 		.get = s390_fpregs_get,
815 		.set = s390_fpregs_set,
816 	},
817 };
818 
819 static const struct user_regset_view user_s390_view = {
820 	.name = UTS_MACHINE,
821 	.e_machine = EM_S390,
822 	.regsets = s390_regsets,
823 	.n = ARRAY_SIZE(s390_regsets)
824 };
825 
826 #ifdef CONFIG_COMPAT
827 static int s390_compat_regs_get(struct task_struct *target,
828 				const struct user_regset *regset,
829 				unsigned int pos, unsigned int count,
830 				void *kbuf, void __user *ubuf)
831 {
832 	if (target == current)
833 		save_access_regs(target->thread.acrs);
834 
835 	if (kbuf) {
836 		compat_ulong_t *k = kbuf;
837 		while (count > 0) {
838 			*k++ = __peek_user_compat(target, pos);
839 			count -= sizeof(*k);
840 			pos += sizeof(*k);
841 		}
842 	} else {
843 		compat_ulong_t __user *u = ubuf;
844 		while (count > 0) {
845 			if (__put_user(__peek_user_compat(target, pos), u++))
846 				return -EFAULT;
847 			count -= sizeof(*u);
848 			pos += sizeof(*u);
849 		}
850 	}
851 	return 0;
852 }
853 
854 static int s390_compat_regs_set(struct task_struct *target,
855 				const struct user_regset *regset,
856 				unsigned int pos, unsigned int count,
857 				const void *kbuf, const void __user *ubuf)
858 {
859 	int rc = 0;
860 
861 	if (target == current)
862 		save_access_regs(target->thread.acrs);
863 
864 	if (kbuf) {
865 		const compat_ulong_t *k = kbuf;
866 		while (count > 0 && !rc) {
867 			rc = __poke_user_compat(target, pos, *k++);
868 			count -= sizeof(*k);
869 			pos += sizeof(*k);
870 		}
871 	} else {
872 		const compat_ulong_t  __user *u = ubuf;
873 		while (count > 0 && !rc) {
874 			compat_ulong_t word;
875 			rc = __get_user(word, u++);
876 			if (rc)
877 				break;
878 			rc = __poke_user_compat(target, pos, word);
879 			count -= sizeof(*u);
880 			pos += sizeof(*u);
881 		}
882 	}
883 
884 	if (rc == 0 && target == current)
885 		restore_access_regs(target->thread.acrs);
886 
887 	return rc;
888 }
889 
890 static const struct user_regset s390_compat_regsets[] = {
891 	[REGSET_GENERAL] = {
892 		.core_note_type = NT_PRSTATUS,
893 		.n = sizeof(s390_compat_regs) / sizeof(compat_long_t),
894 		.size = sizeof(compat_long_t),
895 		.align = sizeof(compat_long_t),
896 		.get = s390_compat_regs_get,
897 		.set = s390_compat_regs_set,
898 	},
899 	[REGSET_FP] = {
900 		.core_note_type = NT_PRFPREG,
901 		.n = sizeof(s390_fp_regs) / sizeof(compat_long_t),
902 		.size = sizeof(compat_long_t),
903 		.align = sizeof(compat_long_t),
904 		.get = s390_fpregs_get,
905 		.set = s390_fpregs_set,
906 	},
907 };
908 
909 static const struct user_regset_view user_s390_compat_view = {
910 	.name = "s390",
911 	.e_machine = EM_S390,
912 	.regsets = s390_compat_regsets,
913 	.n = ARRAY_SIZE(s390_compat_regsets)
914 };
915 #endif
916 
917 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
918 {
919 #ifdef CONFIG_COMPAT
920 	if (test_tsk_thread_flag(task, TIF_31BIT))
921 		return &user_s390_compat_view;
922 #endif
923 	return &user_s390_view;
924 }
925