xref: /linux/arch/s390/kernel/ptrace.c (revision 8b1935e6a36b0967efc593d67ed3aebbfbc1f5b1)
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 #define CREATE_TRACE_POINTS
55 #include <trace/events/syscalls.h>
56 
57 enum s390_regset {
58 	REGSET_GENERAL,
59 	REGSET_FP,
60 	REGSET_GENERAL_EXTENDED,
61 };
62 
63 static void
64 FixPerRegisters(struct task_struct *task)
65 {
66 	struct pt_regs *regs;
67 	per_struct *per_info;
68 	per_cr_words cr_words;
69 
70 	regs = task_pt_regs(task);
71 	per_info = (per_struct *) &task->thread.per_info;
72 	per_info->control_regs.bits.em_instruction_fetch =
73 		per_info->single_step | per_info->instruction_fetch;
74 
75 	if (per_info->single_step) {
76 		per_info->control_regs.bits.starting_addr = 0;
77 #ifdef CONFIG_COMPAT
78 		if (is_compat_task())
79 			per_info->control_regs.bits.ending_addr = 0x7fffffffUL;
80 		else
81 #endif
82 			per_info->control_regs.bits.ending_addr = PSW_ADDR_INSN;
83 	} else {
84 		per_info->control_regs.bits.starting_addr =
85 			per_info->starting_addr;
86 		per_info->control_regs.bits.ending_addr =
87 			per_info->ending_addr;
88 	}
89 	/*
90 	 * if any of the control reg tracing bits are on
91 	 * we switch on per in the psw
92 	 */
93 	if (per_info->control_regs.words.cr[0] & PER_EM_MASK)
94 		regs->psw.mask |= PSW_MASK_PER;
95 	else
96 		regs->psw.mask &= ~PSW_MASK_PER;
97 
98 	if (per_info->control_regs.bits.em_storage_alteration)
99 		per_info->control_regs.bits.storage_alt_space_ctl = 1;
100 	else
101 		per_info->control_regs.bits.storage_alt_space_ctl = 0;
102 
103 	if (task == current) {
104 		__ctl_store(cr_words, 9, 11);
105 		if (memcmp(&cr_words, &per_info->control_regs.words,
106 			   sizeof(cr_words)) != 0)
107 			__ctl_load(per_info->control_regs.words, 9, 11);
108 	}
109 }
110 
111 void user_enable_single_step(struct task_struct *task)
112 {
113 	task->thread.per_info.single_step = 1;
114 	FixPerRegisters(task);
115 }
116 
117 void user_disable_single_step(struct task_struct *task)
118 {
119 	task->thread.per_info.single_step = 0;
120 	FixPerRegisters(task);
121 }
122 
123 /*
124  * Called by kernel/ptrace.c when detaching..
125  *
126  * Make sure single step bits etc are not set.
127  */
128 void
129 ptrace_disable(struct task_struct *child)
130 {
131 	/* make sure the single step bit is not set. */
132 	user_disable_single_step(child);
133 }
134 
135 #ifndef CONFIG_64BIT
136 # define __ADDR_MASK 3
137 #else
138 # define __ADDR_MASK 7
139 #endif
140 
141 /*
142  * Read the word at offset addr from the user area of a process. The
143  * trouble here is that the information is littered over different
144  * locations. The process registers are found on the kernel stack,
145  * the floating point stuff and the trace settings are stored in
146  * the task structure. In addition the different structures in
147  * struct user contain pad bytes that should be read as zeroes.
148  * Lovely...
149  */
150 static unsigned long __peek_user(struct task_struct *child, addr_t addr)
151 {
152 	struct user *dummy = NULL;
153 	addr_t offset, tmp;
154 
155 	if (addr < (addr_t) &dummy->regs.acrs) {
156 		/*
157 		 * psw and gprs are stored on the stack
158 		 */
159 		tmp = *(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr);
160 		if (addr == (addr_t) &dummy->regs.psw.mask)
161 			/* Remove per bit from user psw. */
162 			tmp &= ~PSW_MASK_PER;
163 
164 	} else if (addr < (addr_t) &dummy->regs.orig_gpr2) {
165 		/*
166 		 * access registers are stored in the thread structure
167 		 */
168 		offset = addr - (addr_t) &dummy->regs.acrs;
169 #ifdef CONFIG_64BIT
170 		/*
171 		 * Very special case: old & broken 64 bit gdb reading
172 		 * from acrs[15]. Result is a 64 bit value. Read the
173 		 * 32 bit acrs[15] value and shift it by 32. Sick...
174 		 */
175 		if (addr == (addr_t) &dummy->regs.acrs[15])
176 			tmp = ((unsigned long) child->thread.acrs[15]) << 32;
177 		else
178 #endif
179 		tmp = *(addr_t *)((addr_t) &child->thread.acrs + offset);
180 
181 	} else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
182 		/*
183 		 * orig_gpr2 is stored on the kernel stack
184 		 */
185 		tmp = (addr_t) task_pt_regs(child)->orig_gpr2;
186 
187 	} else if (addr < (addr_t) &dummy->regs.fp_regs) {
188 		/*
189 		 * prevent reads of padding hole between
190 		 * orig_gpr2 and fp_regs on s390.
191 		 */
192 		tmp = 0;
193 
194 	} else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
195 		/*
196 		 * floating point regs. are stored in the thread structure
197 		 */
198 		offset = addr - (addr_t) &dummy->regs.fp_regs;
199 		tmp = *(addr_t *)((addr_t) &child->thread.fp_regs + offset);
200 		if (addr == (addr_t) &dummy->regs.fp_regs.fpc)
201 			tmp &= (unsigned long) FPC_VALID_MASK
202 				<< (BITS_PER_LONG - 32);
203 
204 	} else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
205 		/*
206 		 * per_info is found in the thread structure
207 		 */
208 		offset = addr - (addr_t) &dummy->regs.per_info;
209 		tmp = *(addr_t *)((addr_t) &child->thread.per_info + offset);
210 
211 	} else
212 		tmp = 0;
213 
214 	return tmp;
215 }
216 
217 static int
218 peek_user(struct task_struct *child, addr_t addr, addr_t data)
219 {
220 	addr_t tmp, mask;
221 
222 	/*
223 	 * Stupid gdb peeks/pokes the access registers in 64 bit with
224 	 * an alignment of 4. Programmers from hell...
225 	 */
226 	mask = __ADDR_MASK;
227 #ifdef CONFIG_64BIT
228 	if (addr >= (addr_t) &((struct user *) NULL)->regs.acrs &&
229 	    addr < (addr_t) &((struct user *) NULL)->regs.orig_gpr2)
230 		mask = 3;
231 #endif
232 	if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
233 		return -EIO;
234 
235 	tmp = __peek_user(child, addr);
236 	return put_user(tmp, (addr_t __user *) data);
237 }
238 
239 /*
240  * Write a word to the user area of a process at location addr. This
241  * operation does have an additional problem compared to peek_user.
242  * Stores to the program status word and on the floating point
243  * control register needs to get checked for validity.
244  */
245 static int __poke_user(struct task_struct *child, addr_t addr, addr_t data)
246 {
247 	struct user *dummy = NULL;
248 	addr_t offset;
249 
250 	if (addr < (addr_t) &dummy->regs.acrs) {
251 		/*
252 		 * psw and gprs are stored on the stack
253 		 */
254 		if (addr == (addr_t) &dummy->regs.psw.mask &&
255 #ifdef CONFIG_COMPAT
256 		    data != PSW_MASK_MERGE(psw_user32_bits, data) &&
257 #endif
258 		    data != PSW_MASK_MERGE(psw_user_bits, data))
259 			/* Invalid psw mask. */
260 			return -EINVAL;
261 #ifndef CONFIG_64BIT
262 		if (addr == (addr_t) &dummy->regs.psw.addr)
263 			/* I'd like to reject addresses without the
264 			   high order bit but older gdb's rely on it */
265 			data |= PSW_ADDR_AMODE;
266 #endif
267 		*(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr) = data;
268 
269 	} else if (addr < (addr_t) (&dummy->regs.orig_gpr2)) {
270 		/*
271 		 * access registers are stored in the thread structure
272 		 */
273 		offset = addr - (addr_t) &dummy->regs.acrs;
274 #ifdef CONFIG_64BIT
275 		/*
276 		 * Very special case: old & broken 64 bit gdb writing
277 		 * to acrs[15] with a 64 bit value. Ignore the lower
278 		 * half of the value and write the upper 32 bit to
279 		 * acrs[15]. Sick...
280 		 */
281 		if (addr == (addr_t) &dummy->regs.acrs[15])
282 			child->thread.acrs[15] = (unsigned int) (data >> 32);
283 		else
284 #endif
285 		*(addr_t *)((addr_t) &child->thread.acrs + offset) = data;
286 
287 	} else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
288 		/*
289 		 * orig_gpr2 is stored on the kernel stack
290 		 */
291 		task_pt_regs(child)->orig_gpr2 = data;
292 
293 	} else if (addr < (addr_t) &dummy->regs.fp_regs) {
294 		/*
295 		 * prevent writes of padding hole between
296 		 * orig_gpr2 and fp_regs on s390.
297 		 */
298 		return 0;
299 
300 	} else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
301 		/*
302 		 * floating point regs. are stored in the thread structure
303 		 */
304 		if (addr == (addr_t) &dummy->regs.fp_regs.fpc &&
305 		    (data & ~((unsigned long) FPC_VALID_MASK
306 			      << (BITS_PER_LONG - 32))) != 0)
307 			return -EINVAL;
308 		offset = addr - (addr_t) &dummy->regs.fp_regs;
309 		*(addr_t *)((addr_t) &child->thread.fp_regs + offset) = data;
310 
311 	} else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
312 		/*
313 		 * per_info is found in the thread structure
314 		 */
315 		offset = addr - (addr_t) &dummy->regs.per_info;
316 		*(addr_t *)((addr_t) &child->thread.per_info + offset) = data;
317 
318 	}
319 
320 	FixPerRegisters(child);
321 	return 0;
322 }
323 
324 static int
325 poke_user(struct task_struct *child, addr_t addr, addr_t data)
326 {
327 	addr_t mask;
328 
329 	/*
330 	 * Stupid gdb peeks/pokes the access registers in 64 bit with
331 	 * an alignment of 4. Programmers from hell indeed...
332 	 */
333 	mask = __ADDR_MASK;
334 #ifdef CONFIG_64BIT
335 	if (addr >= (addr_t) &((struct user *) NULL)->regs.acrs &&
336 	    addr < (addr_t) &((struct user *) NULL)->regs.orig_gpr2)
337 		mask = 3;
338 #endif
339 	if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
340 		return -EIO;
341 
342 	return __poke_user(child, addr, data);
343 }
344 
345 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
346 {
347 	ptrace_area parea;
348 	int copied, ret;
349 
350 	switch (request) {
351 	case PTRACE_PEEKUSR:
352 		/* read the word at location addr in the USER area. */
353 		return peek_user(child, addr, data);
354 
355 	case PTRACE_POKEUSR:
356 		/* write the word at location addr in the USER area */
357 		return poke_user(child, addr, data);
358 
359 	case PTRACE_PEEKUSR_AREA:
360 	case PTRACE_POKEUSR_AREA:
361 		if (copy_from_user(&parea, (void __force __user *) addr,
362 							sizeof(parea)))
363 			return -EFAULT;
364 		addr = parea.kernel_addr;
365 		data = parea.process_addr;
366 		copied = 0;
367 		while (copied < parea.len) {
368 			if (request == PTRACE_PEEKUSR_AREA)
369 				ret = peek_user(child, addr, data);
370 			else {
371 				addr_t utmp;
372 				if (get_user(utmp,
373 					     (addr_t __force __user *) data))
374 					return -EFAULT;
375 				ret = poke_user(child, addr, utmp);
376 			}
377 			if (ret)
378 				return ret;
379 			addr += sizeof(unsigned long);
380 			data += sizeof(unsigned long);
381 			copied += sizeof(unsigned long);
382 		}
383 		return 0;
384 	default:
385 		/* Removing high order bit from addr (only for 31 bit). */
386 		addr &= PSW_ADDR_INSN;
387 		return ptrace_request(child, request, addr, data);
388 	}
389 }
390 
391 #ifdef CONFIG_COMPAT
392 /*
393  * Now the fun part starts... a 31 bit program running in the
394  * 31 bit emulation tracing another program. PTRACE_PEEKTEXT,
395  * PTRACE_PEEKDATA, PTRACE_POKETEXT and PTRACE_POKEDATA are easy
396  * to handle, the difference to the 64 bit versions of the requests
397  * is that the access is done in multiples of 4 byte instead of
398  * 8 bytes (sizeof(unsigned long) on 31/64 bit).
399  * The ugly part are PTRACE_PEEKUSR, PTRACE_PEEKUSR_AREA,
400  * PTRACE_POKEUSR and PTRACE_POKEUSR_AREA. If the traced program
401  * is a 31 bit program too, the content of struct user can be
402  * emulated. A 31 bit program peeking into the struct user of
403  * a 64 bit program is a no-no.
404  */
405 
406 /*
407  * Same as peek_user but for a 31 bit program.
408  */
409 static u32 __peek_user_compat(struct task_struct *child, addr_t addr)
410 {
411 	struct user32 *dummy32 = NULL;
412 	per_struct32 *dummy_per32 = NULL;
413 	addr_t offset;
414 	__u32 tmp;
415 
416 	if (addr < (addr_t) &dummy32->regs.acrs) {
417 		/*
418 		 * psw and gprs are stored on the stack
419 		 */
420 		if (addr == (addr_t) &dummy32->regs.psw.mask) {
421 			/* Fake a 31 bit psw mask. */
422 			tmp = (__u32)(task_pt_regs(child)->psw.mask >> 32);
423 			tmp = PSW32_MASK_MERGE(psw32_user_bits, tmp);
424 		} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
425 			/* Fake a 31 bit psw address. */
426 			tmp = (__u32) task_pt_regs(child)->psw.addr |
427 				PSW32_ADDR_AMODE31;
428 		} else {
429 			/* gpr 0-15 */
430 			tmp = *(__u32 *)((addr_t) &task_pt_regs(child)->psw +
431 					 addr*2 + 4);
432 		}
433 	} else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
434 		/*
435 		 * access registers are stored in the thread structure
436 		 */
437 		offset = addr - (addr_t) &dummy32->regs.acrs;
438 		tmp = *(__u32*)((addr_t) &child->thread.acrs + offset);
439 
440 	} else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
441 		/*
442 		 * orig_gpr2 is stored on the kernel stack
443 		 */
444 		tmp = *(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4);
445 
446 	} else if (addr < (addr_t) &dummy32->regs.fp_regs) {
447 		/*
448 		 * prevent reads of padding hole between
449 		 * orig_gpr2 and fp_regs on s390.
450 		 */
451 		tmp = 0;
452 
453 	} else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
454 		/*
455 		 * floating point regs. are stored in the thread structure
456 		 */
457 	        offset = addr - (addr_t) &dummy32->regs.fp_regs;
458 		tmp = *(__u32 *)((addr_t) &child->thread.fp_regs + offset);
459 
460 	} else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
461 		/*
462 		 * per_info is found in the thread structure
463 		 */
464 		offset = addr - (addr_t) &dummy32->regs.per_info;
465 		/* This is magic. See per_struct and per_struct32. */
466 		if ((offset >= (addr_t) &dummy_per32->control_regs &&
467 		     offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
468 		    (offset >= (addr_t) &dummy_per32->starting_addr &&
469 		     offset <= (addr_t) &dummy_per32->ending_addr) ||
470 		    offset == (addr_t) &dummy_per32->lowcore.words.address)
471 			offset = offset*2 + 4;
472 		else
473 			offset = offset*2;
474 		tmp = *(__u32 *)((addr_t) &child->thread.per_info + offset);
475 
476 	} else
477 		tmp = 0;
478 
479 	return tmp;
480 }
481 
482 static int peek_user_compat(struct task_struct *child,
483 			    addr_t addr, addr_t data)
484 {
485 	__u32 tmp;
486 
487 	if (!is_compat_task() || (addr & 3) || addr > sizeof(struct user) - 3)
488 		return -EIO;
489 
490 	tmp = __peek_user_compat(child, addr);
491 	return put_user(tmp, (__u32 __user *) data);
492 }
493 
494 /*
495  * Same as poke_user but for a 31 bit program.
496  */
497 static int __poke_user_compat(struct task_struct *child,
498 			      addr_t addr, addr_t data)
499 {
500 	struct user32 *dummy32 = NULL;
501 	per_struct32 *dummy_per32 = NULL;
502 	__u32 tmp = (__u32) data;
503 	addr_t offset;
504 
505 	if (addr < (addr_t) &dummy32->regs.acrs) {
506 		/*
507 		 * psw, gprs, acrs and orig_gpr2 are stored on the stack
508 		 */
509 		if (addr == (addr_t) &dummy32->regs.psw.mask) {
510 			/* Build a 64 bit psw mask from 31 bit mask. */
511 			if (tmp != PSW32_MASK_MERGE(psw32_user_bits, tmp))
512 				/* Invalid psw mask. */
513 				return -EINVAL;
514 			task_pt_regs(child)->psw.mask =
515 				PSW_MASK_MERGE(psw_user32_bits, (__u64) tmp << 32);
516 		} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
517 			/* Build a 64 bit psw address from 31 bit address. */
518 			task_pt_regs(child)->psw.addr =
519 				(__u64) tmp & PSW32_ADDR_INSN;
520 		} else {
521 			/* gpr 0-15 */
522 			*(__u32*)((addr_t) &task_pt_regs(child)->psw
523 				  + addr*2 + 4) = tmp;
524 		}
525 	} else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
526 		/*
527 		 * access registers are stored in the thread structure
528 		 */
529 		offset = addr - (addr_t) &dummy32->regs.acrs;
530 		*(__u32*)((addr_t) &child->thread.acrs + offset) = tmp;
531 
532 	} else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
533 		/*
534 		 * orig_gpr2 is stored on the kernel stack
535 		 */
536 		*(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4) = tmp;
537 
538 	} else if (addr < (addr_t) &dummy32->regs.fp_regs) {
539 		/*
540 		 * prevent writess of padding hole between
541 		 * orig_gpr2 and fp_regs on s390.
542 		 */
543 		return 0;
544 
545 	} else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
546 		/*
547 		 * floating point regs. are stored in the thread structure
548 		 */
549 		if (addr == (addr_t) &dummy32->regs.fp_regs.fpc &&
550 		    (tmp & ~FPC_VALID_MASK) != 0)
551 			/* Invalid floating point control. */
552 			return -EINVAL;
553 	        offset = addr - (addr_t) &dummy32->regs.fp_regs;
554 		*(__u32 *)((addr_t) &child->thread.fp_regs + offset) = tmp;
555 
556 	} else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
557 		/*
558 		 * per_info is found in the thread structure.
559 		 */
560 		offset = addr - (addr_t) &dummy32->regs.per_info;
561 		/*
562 		 * This is magic. See per_struct and per_struct32.
563 		 * By incident the offsets in per_struct are exactly
564 		 * twice the offsets in per_struct32 for all fields.
565 		 * The 8 byte fields need special handling though,
566 		 * because the second half (bytes 4-7) is needed and
567 		 * not the first half.
568 		 */
569 		if ((offset >= (addr_t) &dummy_per32->control_regs &&
570 		     offset < (addr_t) (&dummy_per32->control_regs + 1)) ||
571 		    (offset >= (addr_t) &dummy_per32->starting_addr &&
572 		     offset <= (addr_t) &dummy_per32->ending_addr) ||
573 		    offset == (addr_t) &dummy_per32->lowcore.words.address)
574 			offset = offset*2 + 4;
575 		else
576 			offset = offset*2;
577 		*(__u32 *)((addr_t) &child->thread.per_info + offset) = tmp;
578 
579 	}
580 
581 	FixPerRegisters(child);
582 	return 0;
583 }
584 
585 static int poke_user_compat(struct task_struct *child,
586 			    addr_t addr, addr_t data)
587 {
588 	if (!is_compat_task() || (addr & 3) || addr > sizeof(struct user32) - 3)
589 		return -EIO;
590 
591 	return __poke_user_compat(child, addr, data);
592 }
593 
594 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
595 			compat_ulong_t caddr, compat_ulong_t cdata)
596 {
597 	unsigned long addr = caddr;
598 	unsigned long data = cdata;
599 	ptrace_area_emu31 parea;
600 	int copied, ret;
601 
602 	switch (request) {
603 	case PTRACE_PEEKUSR:
604 		/* read the word at location addr in the USER area. */
605 		return peek_user_compat(child, addr, data);
606 
607 	case PTRACE_POKEUSR:
608 		/* write the word at location addr in the USER area */
609 		return poke_user_compat(child, addr, data);
610 
611 	case PTRACE_PEEKUSR_AREA:
612 	case PTRACE_POKEUSR_AREA:
613 		if (copy_from_user(&parea, (void __force __user *) addr,
614 							sizeof(parea)))
615 			return -EFAULT;
616 		addr = parea.kernel_addr;
617 		data = parea.process_addr;
618 		copied = 0;
619 		while (copied < parea.len) {
620 			if (request == PTRACE_PEEKUSR_AREA)
621 				ret = peek_user_compat(child, addr, data);
622 			else {
623 				__u32 utmp;
624 				if (get_user(utmp,
625 					     (__u32 __force __user *) data))
626 					return -EFAULT;
627 				ret = poke_user_compat(child, addr, utmp);
628 			}
629 			if (ret)
630 				return ret;
631 			addr += sizeof(unsigned int);
632 			data += sizeof(unsigned int);
633 			copied += sizeof(unsigned int);
634 		}
635 		return 0;
636 	}
637 	return compat_ptrace_request(child, request, addr, data);
638 }
639 #endif
640 
641 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
642 {
643 	long ret;
644 
645 	/* Do the secure computing check first. */
646 	secure_computing(regs->gprs[2]);
647 
648 	/*
649 	 * The sysc_tracesys code in entry.S stored the system
650 	 * call number to gprs[2].
651 	 */
652 	ret = regs->gprs[2];
653 	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
654 	    (tracehook_report_syscall_entry(regs) ||
655 	     regs->gprs[2] >= NR_syscalls)) {
656 		/*
657 		 * Tracing decided this syscall should not happen or the
658 		 * debugger stored an invalid system call number. Skip
659 		 * the system call and the system call restart handling.
660 		 */
661 		regs->svcnr = 0;
662 		ret = -1;
663 	}
664 
665 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
666 		trace_sys_enter(regs, regs->gprs[2]);
667 
668 	if (unlikely(current->audit_context))
669 		audit_syscall_entry(is_compat_task() ?
670 					AUDIT_ARCH_S390 : AUDIT_ARCH_S390X,
671 				    regs->gprs[2], regs->orig_gpr2,
672 				    regs->gprs[3], regs->gprs[4],
673 				    regs->gprs[5]);
674 	return ret;
675 }
676 
677 asmlinkage void do_syscall_trace_exit(struct pt_regs *regs)
678 {
679 	if (unlikely(current->audit_context))
680 		audit_syscall_exit(AUDITSC_RESULT(regs->gprs[2]),
681 				   regs->gprs[2]);
682 
683 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
684 		trace_sys_exit(regs, regs->gprs[2]);
685 
686 	if (test_thread_flag(TIF_SYSCALL_TRACE))
687 		tracehook_report_syscall_exit(regs, 0);
688 }
689 
690 /*
691  * user_regset definitions.
692  */
693 
694 static int s390_regs_get(struct task_struct *target,
695 			 const struct user_regset *regset,
696 			 unsigned int pos, unsigned int count,
697 			 void *kbuf, void __user *ubuf)
698 {
699 	if (target == current)
700 		save_access_regs(target->thread.acrs);
701 
702 	if (kbuf) {
703 		unsigned long *k = kbuf;
704 		while (count > 0) {
705 			*k++ = __peek_user(target, pos);
706 			count -= sizeof(*k);
707 			pos += sizeof(*k);
708 		}
709 	} else {
710 		unsigned long __user *u = ubuf;
711 		while (count > 0) {
712 			if (__put_user(__peek_user(target, pos), u++))
713 				return -EFAULT;
714 			count -= sizeof(*u);
715 			pos += sizeof(*u);
716 		}
717 	}
718 	return 0;
719 }
720 
721 static int s390_regs_set(struct task_struct *target,
722 			 const struct user_regset *regset,
723 			 unsigned int pos, unsigned int count,
724 			 const void *kbuf, const void __user *ubuf)
725 {
726 	int rc = 0;
727 
728 	if (target == current)
729 		save_access_regs(target->thread.acrs);
730 
731 	if (kbuf) {
732 		const unsigned long *k = kbuf;
733 		while (count > 0 && !rc) {
734 			rc = __poke_user(target, pos, *k++);
735 			count -= sizeof(*k);
736 			pos += sizeof(*k);
737 		}
738 	} else {
739 		const unsigned long  __user *u = ubuf;
740 		while (count > 0 && !rc) {
741 			unsigned long word;
742 			rc = __get_user(word, u++);
743 			if (rc)
744 				break;
745 			rc = __poke_user(target, pos, word);
746 			count -= sizeof(*u);
747 			pos += sizeof(*u);
748 		}
749 	}
750 
751 	if (rc == 0 && target == current)
752 		restore_access_regs(target->thread.acrs);
753 
754 	return rc;
755 }
756 
757 static int s390_fpregs_get(struct task_struct *target,
758 			   const struct user_regset *regset, unsigned int pos,
759 			   unsigned int count, void *kbuf, void __user *ubuf)
760 {
761 	if (target == current)
762 		save_fp_regs(&target->thread.fp_regs);
763 
764 	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
765 				   &target->thread.fp_regs, 0, -1);
766 }
767 
768 static int s390_fpregs_set(struct task_struct *target,
769 			   const struct user_regset *regset, unsigned int pos,
770 			   unsigned int count, const void *kbuf,
771 			   const void __user *ubuf)
772 {
773 	int rc = 0;
774 
775 	if (target == current)
776 		save_fp_regs(&target->thread.fp_regs);
777 
778 	/* If setting FPC, must validate it first. */
779 	if (count > 0 && pos < offsetof(s390_fp_regs, fprs)) {
780 		u32 fpc[2] = { target->thread.fp_regs.fpc, 0 };
781 		rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &fpc,
782 					0, offsetof(s390_fp_regs, fprs));
783 		if (rc)
784 			return rc;
785 		if ((fpc[0] & ~FPC_VALID_MASK) != 0 || fpc[1] != 0)
786 			return -EINVAL;
787 		target->thread.fp_regs.fpc = fpc[0];
788 	}
789 
790 	if (rc == 0 && count > 0)
791 		rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
792 					target->thread.fp_regs.fprs,
793 					offsetof(s390_fp_regs, fprs), -1);
794 
795 	if (rc == 0 && target == current)
796 		restore_fp_regs(&target->thread.fp_regs);
797 
798 	return rc;
799 }
800 
801 static const struct user_regset s390_regsets[] = {
802 	[REGSET_GENERAL] = {
803 		.core_note_type = NT_PRSTATUS,
804 		.n = sizeof(s390_regs) / sizeof(long),
805 		.size = sizeof(long),
806 		.align = sizeof(long),
807 		.get = s390_regs_get,
808 		.set = s390_regs_set,
809 	},
810 	[REGSET_FP] = {
811 		.core_note_type = NT_PRFPREG,
812 		.n = sizeof(s390_fp_regs) / sizeof(long),
813 		.size = sizeof(long),
814 		.align = sizeof(long),
815 		.get = s390_fpregs_get,
816 		.set = s390_fpregs_set,
817 	},
818 };
819 
820 static const struct user_regset_view user_s390_view = {
821 	.name = UTS_MACHINE,
822 	.e_machine = EM_S390,
823 	.regsets = s390_regsets,
824 	.n = ARRAY_SIZE(s390_regsets)
825 };
826 
827 #ifdef CONFIG_COMPAT
828 static int s390_compat_regs_get(struct task_struct *target,
829 				const struct user_regset *regset,
830 				unsigned int pos, unsigned int count,
831 				void *kbuf, void __user *ubuf)
832 {
833 	if (target == current)
834 		save_access_regs(target->thread.acrs);
835 
836 	if (kbuf) {
837 		compat_ulong_t *k = kbuf;
838 		while (count > 0) {
839 			*k++ = __peek_user_compat(target, pos);
840 			count -= sizeof(*k);
841 			pos += sizeof(*k);
842 		}
843 	} else {
844 		compat_ulong_t __user *u = ubuf;
845 		while (count > 0) {
846 			if (__put_user(__peek_user_compat(target, pos), u++))
847 				return -EFAULT;
848 			count -= sizeof(*u);
849 			pos += sizeof(*u);
850 		}
851 	}
852 	return 0;
853 }
854 
855 static int s390_compat_regs_set(struct task_struct *target,
856 				const struct user_regset *regset,
857 				unsigned int pos, unsigned int count,
858 				const void *kbuf, const void __user *ubuf)
859 {
860 	int rc = 0;
861 
862 	if (target == current)
863 		save_access_regs(target->thread.acrs);
864 
865 	if (kbuf) {
866 		const compat_ulong_t *k = kbuf;
867 		while (count > 0 && !rc) {
868 			rc = __poke_user_compat(target, pos, *k++);
869 			count -= sizeof(*k);
870 			pos += sizeof(*k);
871 		}
872 	} else {
873 		const compat_ulong_t  __user *u = ubuf;
874 		while (count > 0 && !rc) {
875 			compat_ulong_t word;
876 			rc = __get_user(word, u++);
877 			if (rc)
878 				break;
879 			rc = __poke_user_compat(target, pos, word);
880 			count -= sizeof(*u);
881 			pos += sizeof(*u);
882 		}
883 	}
884 
885 	if (rc == 0 && target == current)
886 		restore_access_regs(target->thread.acrs);
887 
888 	return rc;
889 }
890 
891 static int s390_compat_regs_high_get(struct task_struct *target,
892 				     const struct user_regset *regset,
893 				     unsigned int pos, unsigned int count,
894 				     void *kbuf, void __user *ubuf)
895 {
896 	compat_ulong_t *gprs_high;
897 
898 	gprs_high = (compat_ulong_t *)
899 		&task_pt_regs(target)->gprs[pos / sizeof(compat_ulong_t)];
900 	if (kbuf) {
901 		compat_ulong_t *k = kbuf;
902 		while (count > 0) {
903 			*k++ = *gprs_high;
904 			gprs_high += 2;
905 			count -= sizeof(*k);
906 		}
907 	} else {
908 		compat_ulong_t __user *u = ubuf;
909 		while (count > 0) {
910 			if (__put_user(*gprs_high, u++))
911 				return -EFAULT;
912 			gprs_high += 2;
913 			count -= sizeof(*u);
914 		}
915 	}
916 	return 0;
917 }
918 
919 static int s390_compat_regs_high_set(struct task_struct *target,
920 				     const struct user_regset *regset,
921 				     unsigned int pos, unsigned int count,
922 				     const void *kbuf, const void __user *ubuf)
923 {
924 	compat_ulong_t *gprs_high;
925 	int rc = 0;
926 
927 	gprs_high = (compat_ulong_t *)
928 		&task_pt_regs(target)->gprs[pos / sizeof(compat_ulong_t)];
929 	if (kbuf) {
930 		const compat_ulong_t *k = kbuf;
931 		while (count > 0) {
932 			*gprs_high = *k++;
933 			*gprs_high += 2;
934 			count -= sizeof(*k);
935 		}
936 	} else {
937 		const compat_ulong_t  __user *u = ubuf;
938 		while (count > 0 && !rc) {
939 			unsigned long word;
940 			rc = __get_user(word, u++);
941 			if (rc)
942 				break;
943 			*gprs_high = word;
944 			*gprs_high += 2;
945 			count -= sizeof(*u);
946 		}
947 	}
948 
949 	return rc;
950 }
951 
952 static const struct user_regset s390_compat_regsets[] = {
953 	[REGSET_GENERAL] = {
954 		.core_note_type = NT_PRSTATUS,
955 		.n = sizeof(s390_compat_regs) / sizeof(compat_long_t),
956 		.size = sizeof(compat_long_t),
957 		.align = sizeof(compat_long_t),
958 		.get = s390_compat_regs_get,
959 		.set = s390_compat_regs_set,
960 	},
961 	[REGSET_FP] = {
962 		.core_note_type = NT_PRFPREG,
963 		.n = sizeof(s390_fp_regs) / sizeof(compat_long_t),
964 		.size = sizeof(compat_long_t),
965 		.align = sizeof(compat_long_t),
966 		.get = s390_fpregs_get,
967 		.set = s390_fpregs_set,
968 	},
969 	[REGSET_GENERAL_EXTENDED] = {
970 		.core_note_type = NT_S390_HIGH_GPRS,
971 		.n = sizeof(s390_compat_regs_high) / sizeof(compat_long_t),
972 		.size = sizeof(compat_long_t),
973 		.align = sizeof(compat_long_t),
974 		.get = s390_compat_regs_high_get,
975 		.set = s390_compat_regs_high_set,
976 	},
977 };
978 
979 static const struct user_regset_view user_s390_compat_view = {
980 	.name = "s390",
981 	.e_machine = EM_S390,
982 	.regsets = s390_compat_regsets,
983 	.n = ARRAY_SIZE(s390_compat_regsets)
984 };
985 #endif
986 
987 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
988 {
989 #ifdef CONFIG_COMPAT
990 	if (test_tsk_thread_flag(task, TIF_31BIT))
991 		return &user_s390_compat_view;
992 #endif
993 	return &user_s390_view;
994 }
995 
996 static const char *gpr_names[NUM_GPRS] = {
997 	"r0", "r1",  "r2",  "r3",  "r4",  "r5",  "r6",  "r7",
998 	"r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
999 };
1000 
1001 unsigned long regs_get_register(struct pt_regs *regs, unsigned int offset)
1002 {
1003 	if (offset >= NUM_GPRS)
1004 		return 0;
1005 	return regs->gprs[offset];
1006 }
1007 
1008 int regs_query_register_offset(const char *name)
1009 {
1010 	unsigned long offset;
1011 
1012 	if (!name || *name != 'r')
1013 		return -EINVAL;
1014 	if (strict_strtoul(name + 1, 10, &offset))
1015 		return -EINVAL;
1016 	if (offset >= NUM_GPRS)
1017 		return -EINVAL;
1018 	return offset;
1019 }
1020 
1021 const char *regs_query_register_name(unsigned int offset)
1022 {
1023 	if (offset >= NUM_GPRS)
1024 		return NULL;
1025 	return gpr_names[offset];
1026 }
1027 
1028 static int regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
1029 {
1030 	unsigned long ksp = kernel_stack_pointer(regs);
1031 
1032 	return (addr & ~(THREAD_SIZE - 1)) == (ksp & ~(THREAD_SIZE - 1));
1033 }
1034 
1035 /**
1036  * regs_get_kernel_stack_nth() - get Nth entry of the stack
1037  * @regs:pt_regs which contains kernel stack pointer.
1038  * @n:stack entry number.
1039  *
1040  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
1041  * is specifined by @regs. If the @n th entry is NOT in the kernel stack,
1042  * this returns 0.
1043  */
1044 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
1045 {
1046 	unsigned long addr;
1047 
1048 	addr = kernel_stack_pointer(regs) + n * sizeof(long);
1049 	if (!regs_within_kernel_stack(regs, addr))
1050 		return 0;
1051 	return *(unsigned long *)addr;
1052 }
1053