xref: /openbmc/linux/arch/s390/kernel/ptrace.c (revision 4bce6fce)
1 /*
2  *  Ptrace user space interface.
3  *
4  *    Copyright IBM Corp. 1999, 2010
5  *    Author(s): Denis Joseph Barrow
6  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
7  */
8 
9 #include <linux/kernel.h>
10 #include <linux/sched.h>
11 #include <linux/mm.h>
12 #include <linux/smp.h>
13 #include <linux/errno.h>
14 #include <linux/ptrace.h>
15 #include <linux/user.h>
16 #include <linux/security.h>
17 #include <linux/audit.h>
18 #include <linux/signal.h>
19 #include <linux/elf.h>
20 #include <linux/regset.h>
21 #include <linux/tracehook.h>
22 #include <linux/seccomp.h>
23 #include <linux/compat.h>
24 #include <trace/syscall.h>
25 #include <asm/segment.h>
26 #include <asm/page.h>
27 #include <asm/pgtable.h>
28 #include <asm/pgalloc.h>
29 #include <asm/uaccess.h>
30 #include <asm/unistd.h>
31 #include <asm/switch_to.h>
32 #include "entry.h"
33 
34 #ifdef CONFIG_COMPAT
35 #include "compat_ptrace.h"
36 #endif
37 
38 #define CREATE_TRACE_POINTS
39 #include <trace/events/syscalls.h>
40 
41 void update_cr_regs(struct task_struct *task)
42 {
43 	struct pt_regs *regs = task_pt_regs(task);
44 	struct thread_struct *thread = &task->thread;
45 	struct per_regs old, new;
46 
47 	/* Take care of the enable/disable of transactional execution. */
48 	if (MACHINE_HAS_TE || MACHINE_HAS_VX) {
49 		unsigned long cr, cr_new;
50 
51 		__ctl_store(cr, 0, 0);
52 		cr_new = cr;
53 		if (MACHINE_HAS_TE) {
54 			/* Set or clear transaction execution TXC bit 8. */
55 			cr_new |= (1UL << 55);
56 			if (task->thread.per_flags & PER_FLAG_NO_TE)
57 				cr_new &= ~(1UL << 55);
58 		}
59 		if (MACHINE_HAS_VX) {
60 			/* Enable/disable of vector extension */
61 			cr_new &= ~(1UL << 17);
62 			if (task->thread.vxrs)
63 				cr_new |= (1UL << 17);
64 		}
65 		if (cr_new != cr)
66 			__ctl_load(cr_new, 0, 0);
67 		if (MACHINE_HAS_TE) {
68 			/* Set/clear transaction execution TDC bits 62/63. */
69 			__ctl_store(cr, 2, 2);
70 			cr_new = cr & ~3UL;
71 			if (task->thread.per_flags & PER_FLAG_TE_ABORT_RAND) {
72 				if (task->thread.per_flags &
73 				    PER_FLAG_TE_ABORT_RAND_TEND)
74 					cr_new |= 1UL;
75 				else
76 					cr_new |= 2UL;
77 			}
78 			if (cr_new != cr)
79 				__ctl_load(cr_new, 2, 2);
80 		}
81 	}
82 	/* Copy user specified PER registers */
83 	new.control = thread->per_user.control;
84 	new.start = thread->per_user.start;
85 	new.end = thread->per_user.end;
86 
87 	/* merge TIF_SINGLE_STEP into user specified PER registers. */
88 	if (test_tsk_thread_flag(task, TIF_SINGLE_STEP) ||
89 	    test_tsk_thread_flag(task, TIF_UPROBE_SINGLESTEP)) {
90 		if (test_tsk_thread_flag(task, TIF_BLOCK_STEP))
91 			new.control |= PER_EVENT_BRANCH;
92 		else
93 			new.control |= PER_EVENT_IFETCH;
94 		new.control |= PER_CONTROL_SUSPENSION;
95 		new.control |= PER_EVENT_TRANSACTION_END;
96 		if (test_tsk_thread_flag(task, TIF_UPROBE_SINGLESTEP))
97 			new.control |= PER_EVENT_IFETCH;
98 		new.start = 0;
99 		new.end = PSW_ADDR_INSN;
100 	}
101 
102 	/* Take care of the PER enablement bit in the PSW. */
103 	if (!(new.control & PER_EVENT_MASK)) {
104 		regs->psw.mask &= ~PSW_MASK_PER;
105 		return;
106 	}
107 	regs->psw.mask |= PSW_MASK_PER;
108 	__ctl_store(old, 9, 11);
109 	if (memcmp(&new, &old, sizeof(struct per_regs)) != 0)
110 		__ctl_load(new, 9, 11);
111 }
112 
113 void user_enable_single_step(struct task_struct *task)
114 {
115 	clear_tsk_thread_flag(task, TIF_BLOCK_STEP);
116 	set_tsk_thread_flag(task, TIF_SINGLE_STEP);
117 }
118 
119 void user_disable_single_step(struct task_struct *task)
120 {
121 	clear_tsk_thread_flag(task, TIF_BLOCK_STEP);
122 	clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
123 }
124 
125 void user_enable_block_step(struct task_struct *task)
126 {
127 	set_tsk_thread_flag(task, TIF_SINGLE_STEP);
128 	set_tsk_thread_flag(task, TIF_BLOCK_STEP);
129 }
130 
131 /*
132  * Called by kernel/ptrace.c when detaching..
133  *
134  * Clear all debugging related fields.
135  */
136 void ptrace_disable(struct task_struct *task)
137 {
138 	memset(&task->thread.per_user, 0, sizeof(task->thread.per_user));
139 	memset(&task->thread.per_event, 0, sizeof(task->thread.per_event));
140 	clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
141 	clear_pt_regs_flag(task_pt_regs(task), PIF_PER_TRAP);
142 	task->thread.per_flags = 0;
143 }
144 
145 #define __ADDR_MASK 7
146 
147 static inline unsigned long __peek_user_per(struct task_struct *child,
148 					    addr_t addr)
149 {
150 	struct per_struct_kernel *dummy = NULL;
151 
152 	if (addr == (addr_t) &dummy->cr9)
153 		/* Control bits of the active per set. */
154 		return test_thread_flag(TIF_SINGLE_STEP) ?
155 			PER_EVENT_IFETCH : child->thread.per_user.control;
156 	else if (addr == (addr_t) &dummy->cr10)
157 		/* Start address of the active per set. */
158 		return test_thread_flag(TIF_SINGLE_STEP) ?
159 			0 : child->thread.per_user.start;
160 	else if (addr == (addr_t) &dummy->cr11)
161 		/* End address of the active per set. */
162 		return test_thread_flag(TIF_SINGLE_STEP) ?
163 			PSW_ADDR_INSN : child->thread.per_user.end;
164 	else if (addr == (addr_t) &dummy->bits)
165 		/* Single-step bit. */
166 		return test_thread_flag(TIF_SINGLE_STEP) ?
167 			(1UL << (BITS_PER_LONG - 1)) : 0;
168 	else if (addr == (addr_t) &dummy->starting_addr)
169 		/* Start address of the user specified per set. */
170 		return child->thread.per_user.start;
171 	else if (addr == (addr_t) &dummy->ending_addr)
172 		/* End address of the user specified per set. */
173 		return child->thread.per_user.end;
174 	else if (addr == (addr_t) &dummy->perc_atmid)
175 		/* PER code, ATMID and AI of the last PER trap */
176 		return (unsigned long)
177 			child->thread.per_event.cause << (BITS_PER_LONG - 16);
178 	else if (addr == (addr_t) &dummy->address)
179 		/* Address of the last PER trap */
180 		return child->thread.per_event.address;
181 	else if (addr == (addr_t) &dummy->access_id)
182 		/* Access id of the last PER trap */
183 		return (unsigned long)
184 			child->thread.per_event.paid << (BITS_PER_LONG - 8);
185 	return 0;
186 }
187 
188 /*
189  * Read the word at offset addr from the user area of a process. The
190  * trouble here is that the information is littered over different
191  * locations. The process registers are found on the kernel stack,
192  * the floating point stuff and the trace settings are stored in
193  * the task structure. In addition the different structures in
194  * struct user contain pad bytes that should be read as zeroes.
195  * Lovely...
196  */
197 static unsigned long __peek_user(struct task_struct *child, addr_t addr)
198 {
199 	struct user *dummy = NULL;
200 	addr_t offset, tmp;
201 
202 	if (addr < (addr_t) &dummy->regs.acrs) {
203 		/*
204 		 * psw and gprs are stored on the stack
205 		 */
206 		tmp = *(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr);
207 		if (addr == (addr_t) &dummy->regs.psw.mask) {
208 			/* Return a clean psw mask. */
209 			tmp &= PSW_MASK_USER | PSW_MASK_RI;
210 			tmp |= PSW_USER_BITS;
211 		}
212 
213 	} else if (addr < (addr_t) &dummy->regs.orig_gpr2) {
214 		/*
215 		 * access registers are stored in the thread structure
216 		 */
217 		offset = addr - (addr_t) &dummy->regs.acrs;
218 		/*
219 		 * Very special case: old & broken 64 bit gdb reading
220 		 * from acrs[15]. Result is a 64 bit value. Read the
221 		 * 32 bit acrs[15] value and shift it by 32. Sick...
222 		 */
223 		if (addr == (addr_t) &dummy->regs.acrs[15])
224 			tmp = ((unsigned long) child->thread.acrs[15]) << 32;
225 		else
226 			tmp = *(addr_t *)((addr_t) &child->thread.acrs + offset);
227 
228 	} else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
229 		/*
230 		 * orig_gpr2 is stored on the kernel stack
231 		 */
232 		tmp = (addr_t) task_pt_regs(child)->orig_gpr2;
233 
234 	} else if (addr < (addr_t) &dummy->regs.fp_regs) {
235 		/*
236 		 * prevent reads of padding hole between
237 		 * orig_gpr2 and fp_regs on s390.
238 		 */
239 		tmp = 0;
240 
241 	} else if (addr == (addr_t) &dummy->regs.fp_regs.fpc) {
242 		/*
243 		 * floating point control reg. is in the thread structure
244 		 */
245 		tmp = child->thread.fp_regs.fpc;
246 		tmp <<= BITS_PER_LONG - 32;
247 
248 	} else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
249 		/*
250 		 * floating point regs. are either in child->thread.fp_regs
251 		 * or the child->thread.vxrs array
252 		 */
253 		offset = addr - (addr_t) &dummy->regs.fp_regs.fprs;
254 		if (child->thread.vxrs)
255 			tmp = *(addr_t *)
256 			       ((addr_t) child->thread.vxrs + 2*offset);
257 		else
258 			tmp = *(addr_t *)
259 			       ((addr_t) &child->thread.fp_regs.fprs + offset);
260 
261 	} else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
262 		/*
263 		 * Handle access to the per_info structure.
264 		 */
265 		addr -= (addr_t) &dummy->regs.per_info;
266 		tmp = __peek_user_per(child, addr);
267 
268 	} else
269 		tmp = 0;
270 
271 	return tmp;
272 }
273 
274 static int
275 peek_user(struct task_struct *child, addr_t addr, addr_t data)
276 {
277 	addr_t tmp, mask;
278 
279 	/*
280 	 * Stupid gdb peeks/pokes the access registers in 64 bit with
281 	 * an alignment of 4. Programmers from hell...
282 	 */
283 	mask = __ADDR_MASK;
284 	if (addr >= (addr_t) &((struct user *) NULL)->regs.acrs &&
285 	    addr < (addr_t) &((struct user *) NULL)->regs.orig_gpr2)
286 		mask = 3;
287 	if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
288 		return -EIO;
289 
290 	tmp = __peek_user(child, addr);
291 	return put_user(tmp, (addr_t __user *) data);
292 }
293 
294 static inline void __poke_user_per(struct task_struct *child,
295 				   addr_t addr, addr_t data)
296 {
297 	struct per_struct_kernel *dummy = NULL;
298 
299 	/*
300 	 * There are only three fields in the per_info struct that the
301 	 * debugger user can write to.
302 	 * 1) cr9: the debugger wants to set a new PER event mask
303 	 * 2) starting_addr: the debugger wants to set a new starting
304 	 *    address to use with the PER event mask.
305 	 * 3) ending_addr: the debugger wants to set a new ending
306 	 *    address to use with the PER event mask.
307 	 * The user specified PER event mask and the start and end
308 	 * addresses are used only if single stepping is not in effect.
309 	 * Writes to any other field in per_info are ignored.
310 	 */
311 	if (addr == (addr_t) &dummy->cr9)
312 		/* PER event mask of the user specified per set. */
313 		child->thread.per_user.control =
314 			data & (PER_EVENT_MASK | PER_CONTROL_MASK);
315 	else if (addr == (addr_t) &dummy->starting_addr)
316 		/* Starting address of the user specified per set. */
317 		child->thread.per_user.start = data;
318 	else if (addr == (addr_t) &dummy->ending_addr)
319 		/* Ending address of the user specified per set. */
320 		child->thread.per_user.end = data;
321 }
322 
323 /*
324  * Write a word to the user area of a process at location addr. This
325  * operation does have an additional problem compared to peek_user.
326  * Stores to the program status word and on the floating point
327  * control register needs to get checked for validity.
328  */
329 static int __poke_user(struct task_struct *child, addr_t addr, addr_t data)
330 {
331 	struct user *dummy = NULL;
332 	addr_t offset;
333 
334 	if (addr < (addr_t) &dummy->regs.acrs) {
335 		/*
336 		 * psw and gprs are stored on the stack
337 		 */
338 		if (addr == (addr_t) &dummy->regs.psw.mask) {
339 			unsigned long mask = PSW_MASK_USER;
340 
341 			mask |= is_ri_task(child) ? PSW_MASK_RI : 0;
342 			if ((data ^ PSW_USER_BITS) & ~mask)
343 				/* Invalid psw mask. */
344 				return -EINVAL;
345 			if ((data & PSW_MASK_ASC) == PSW_ASC_HOME)
346 				/* Invalid address-space-control bits */
347 				return -EINVAL;
348 			if ((data & PSW_MASK_EA) && !(data & PSW_MASK_BA))
349 				/* Invalid addressing mode bits */
350 				return -EINVAL;
351 		}
352 		*(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr) = data;
353 
354 	} else if (addr < (addr_t) (&dummy->regs.orig_gpr2)) {
355 		/*
356 		 * access registers are stored in the thread structure
357 		 */
358 		offset = addr - (addr_t) &dummy->regs.acrs;
359 		/*
360 		 * Very special case: old & broken 64 bit gdb writing
361 		 * to acrs[15] with a 64 bit value. Ignore the lower
362 		 * half of the value and write the upper 32 bit to
363 		 * acrs[15]. Sick...
364 		 */
365 		if (addr == (addr_t) &dummy->regs.acrs[15])
366 			child->thread.acrs[15] = (unsigned int) (data >> 32);
367 		else
368 			*(addr_t *)((addr_t) &child->thread.acrs + offset) = data;
369 
370 	} else if (addr == (addr_t) &dummy->regs.orig_gpr2) {
371 		/*
372 		 * orig_gpr2 is stored on the kernel stack
373 		 */
374 		task_pt_regs(child)->orig_gpr2 = data;
375 
376 	} else if (addr < (addr_t) &dummy->regs.fp_regs) {
377 		/*
378 		 * prevent writes of padding hole between
379 		 * orig_gpr2 and fp_regs on s390.
380 		 */
381 		return 0;
382 
383 	} else if (addr == (addr_t) &dummy->regs.fp_regs.fpc) {
384 		/*
385 		 * floating point control reg. is in the thread structure
386 		 */
387 		if ((unsigned int) data != 0 ||
388 		    test_fp_ctl(data >> (BITS_PER_LONG - 32)))
389 			return -EINVAL;
390 		child->thread.fp_regs.fpc = data >> (BITS_PER_LONG - 32);
391 
392 	} else if (addr < (addr_t) (&dummy->regs.fp_regs + 1)) {
393 		/*
394 		 * floating point regs. are either in child->thread.fp_regs
395 		 * or the child->thread.vxrs array
396 		 */
397 		offset = addr - (addr_t) &dummy->regs.fp_regs.fprs;
398 		if (child->thread.vxrs)
399 			*(addr_t *)((addr_t)
400 				child->thread.vxrs + 2*offset) = data;
401 		else
402 			*(addr_t *)((addr_t)
403 				&child->thread.fp_regs.fprs + offset) = data;
404 
405 	} else if (addr < (addr_t) (&dummy->regs.per_info + 1)) {
406 		/*
407 		 * Handle access to the per_info structure.
408 		 */
409 		addr -= (addr_t) &dummy->regs.per_info;
410 		__poke_user_per(child, addr, data);
411 
412 	}
413 
414 	return 0;
415 }
416 
417 static int poke_user(struct task_struct *child, addr_t addr, addr_t data)
418 {
419 	addr_t mask;
420 
421 	/*
422 	 * Stupid gdb peeks/pokes the access registers in 64 bit with
423 	 * an alignment of 4. Programmers from hell indeed...
424 	 */
425 	mask = __ADDR_MASK;
426 	if (addr >= (addr_t) &((struct user *) NULL)->regs.acrs &&
427 	    addr < (addr_t) &((struct user *) NULL)->regs.orig_gpr2)
428 		mask = 3;
429 	if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
430 		return -EIO;
431 
432 	return __poke_user(child, addr, data);
433 }
434 
435 long arch_ptrace(struct task_struct *child, long request,
436 		 unsigned long addr, unsigned long data)
437 {
438 	ptrace_area parea;
439 	int copied, ret;
440 
441 	switch (request) {
442 	case PTRACE_PEEKUSR:
443 		/* read the word at location addr in the USER area. */
444 		return peek_user(child, addr, data);
445 
446 	case PTRACE_POKEUSR:
447 		/* write the word at location addr in the USER area */
448 		return poke_user(child, addr, data);
449 
450 	case PTRACE_PEEKUSR_AREA:
451 	case PTRACE_POKEUSR_AREA:
452 		if (copy_from_user(&parea, (void __force __user *) addr,
453 							sizeof(parea)))
454 			return -EFAULT;
455 		addr = parea.kernel_addr;
456 		data = parea.process_addr;
457 		copied = 0;
458 		while (copied < parea.len) {
459 			if (request == PTRACE_PEEKUSR_AREA)
460 				ret = peek_user(child, addr, data);
461 			else {
462 				addr_t utmp;
463 				if (get_user(utmp,
464 					     (addr_t __force __user *) data))
465 					return -EFAULT;
466 				ret = poke_user(child, addr, utmp);
467 			}
468 			if (ret)
469 				return ret;
470 			addr += sizeof(unsigned long);
471 			data += sizeof(unsigned long);
472 			copied += sizeof(unsigned long);
473 		}
474 		return 0;
475 	case PTRACE_GET_LAST_BREAK:
476 		put_user(task_thread_info(child)->last_break,
477 			 (unsigned long __user *) data);
478 		return 0;
479 	case PTRACE_ENABLE_TE:
480 		if (!MACHINE_HAS_TE)
481 			return -EIO;
482 		child->thread.per_flags &= ~PER_FLAG_NO_TE;
483 		return 0;
484 	case PTRACE_DISABLE_TE:
485 		if (!MACHINE_HAS_TE)
486 			return -EIO;
487 		child->thread.per_flags |= PER_FLAG_NO_TE;
488 		child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND;
489 		return 0;
490 	case PTRACE_TE_ABORT_RAND:
491 		if (!MACHINE_HAS_TE || (child->thread.per_flags & PER_FLAG_NO_TE))
492 			return -EIO;
493 		switch (data) {
494 		case 0UL:
495 			child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND;
496 			break;
497 		case 1UL:
498 			child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND;
499 			child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND_TEND;
500 			break;
501 		case 2UL:
502 			child->thread.per_flags |= PER_FLAG_TE_ABORT_RAND;
503 			child->thread.per_flags &= ~PER_FLAG_TE_ABORT_RAND_TEND;
504 			break;
505 		default:
506 			return -EINVAL;
507 		}
508 		return 0;
509 	default:
510 		/* Removing high order bit from addr (only for 31 bit). */
511 		addr &= PSW_ADDR_INSN;
512 		return ptrace_request(child, request, addr, data);
513 	}
514 }
515 
516 #ifdef CONFIG_COMPAT
517 /*
518  * Now the fun part starts... a 31 bit program running in the
519  * 31 bit emulation tracing another program. PTRACE_PEEKTEXT,
520  * PTRACE_PEEKDATA, PTRACE_POKETEXT and PTRACE_POKEDATA are easy
521  * to handle, the difference to the 64 bit versions of the requests
522  * is that the access is done in multiples of 4 byte instead of
523  * 8 bytes (sizeof(unsigned long) on 31/64 bit).
524  * The ugly part are PTRACE_PEEKUSR, PTRACE_PEEKUSR_AREA,
525  * PTRACE_POKEUSR and PTRACE_POKEUSR_AREA. If the traced program
526  * is a 31 bit program too, the content of struct user can be
527  * emulated. A 31 bit program peeking into the struct user of
528  * a 64 bit program is a no-no.
529  */
530 
531 /*
532  * Same as peek_user_per but for a 31 bit program.
533  */
534 static inline __u32 __peek_user_per_compat(struct task_struct *child,
535 					   addr_t addr)
536 {
537 	struct compat_per_struct_kernel *dummy32 = NULL;
538 
539 	if (addr == (addr_t) &dummy32->cr9)
540 		/* Control bits of the active per set. */
541 		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
542 			PER_EVENT_IFETCH : child->thread.per_user.control;
543 	else if (addr == (addr_t) &dummy32->cr10)
544 		/* Start address of the active per set. */
545 		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
546 			0 : child->thread.per_user.start;
547 	else if (addr == (addr_t) &dummy32->cr11)
548 		/* End address of the active per set. */
549 		return test_thread_flag(TIF_SINGLE_STEP) ?
550 			PSW32_ADDR_INSN : child->thread.per_user.end;
551 	else if (addr == (addr_t) &dummy32->bits)
552 		/* Single-step bit. */
553 		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
554 			0x80000000 : 0;
555 	else if (addr == (addr_t) &dummy32->starting_addr)
556 		/* Start address of the user specified per set. */
557 		return (__u32) child->thread.per_user.start;
558 	else if (addr == (addr_t) &dummy32->ending_addr)
559 		/* End address of the user specified per set. */
560 		return (__u32) child->thread.per_user.end;
561 	else if (addr == (addr_t) &dummy32->perc_atmid)
562 		/* PER code, ATMID and AI of the last PER trap */
563 		return (__u32) child->thread.per_event.cause << 16;
564 	else if (addr == (addr_t) &dummy32->address)
565 		/* Address of the last PER trap */
566 		return (__u32) child->thread.per_event.address;
567 	else if (addr == (addr_t) &dummy32->access_id)
568 		/* Access id of the last PER trap */
569 		return (__u32) child->thread.per_event.paid << 24;
570 	return 0;
571 }
572 
573 /*
574  * Same as peek_user but for a 31 bit program.
575  */
576 static u32 __peek_user_compat(struct task_struct *child, addr_t addr)
577 {
578 	struct compat_user *dummy32 = NULL;
579 	addr_t offset;
580 	__u32 tmp;
581 
582 	if (addr < (addr_t) &dummy32->regs.acrs) {
583 		struct pt_regs *regs = task_pt_regs(child);
584 		/*
585 		 * psw and gprs are stored on the stack
586 		 */
587 		if (addr == (addr_t) &dummy32->regs.psw.mask) {
588 			/* Fake a 31 bit psw mask. */
589 			tmp = (__u32)(regs->psw.mask >> 32);
590 			tmp &= PSW32_MASK_USER | PSW32_MASK_RI;
591 			tmp |= PSW32_USER_BITS;
592 		} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
593 			/* Fake a 31 bit psw address. */
594 			tmp = (__u32) regs->psw.addr |
595 				(__u32)(regs->psw.mask & PSW_MASK_BA);
596 		} else {
597 			/* gpr 0-15 */
598 			tmp = *(__u32 *)((addr_t) &regs->psw + addr*2 + 4);
599 		}
600 	} else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
601 		/*
602 		 * access registers are stored in the thread structure
603 		 */
604 		offset = addr - (addr_t) &dummy32->regs.acrs;
605 		tmp = *(__u32*)((addr_t) &child->thread.acrs + offset);
606 
607 	} else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
608 		/*
609 		 * orig_gpr2 is stored on the kernel stack
610 		 */
611 		tmp = *(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4);
612 
613 	} else if (addr < (addr_t) &dummy32->regs.fp_regs) {
614 		/*
615 		 * prevent reads of padding hole between
616 		 * orig_gpr2 and fp_regs on s390.
617 		 */
618 		tmp = 0;
619 
620 	} else if (addr == (addr_t) &dummy32->regs.fp_regs.fpc) {
621 		/*
622 		 * floating point control reg. is in the thread structure
623 		 */
624 		tmp = child->thread.fp_regs.fpc;
625 
626 	} else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
627 		/*
628 		 * floating point regs. are either in child->thread.fp_regs
629 		 * or the child->thread.vxrs array
630 		 */
631 		offset = addr - (addr_t) &dummy32->regs.fp_regs.fprs;
632 		if (child->thread.vxrs)
633 			tmp = *(__u32 *)
634 			       ((addr_t) child->thread.vxrs + 2*offset);
635 		else
636 			tmp = *(__u32 *)
637 			       ((addr_t) &child->thread.fp_regs.fprs + offset);
638 
639 	} else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
640 		/*
641 		 * Handle access to the per_info structure.
642 		 */
643 		addr -= (addr_t) &dummy32->regs.per_info;
644 		tmp = __peek_user_per_compat(child, addr);
645 
646 	} else
647 		tmp = 0;
648 
649 	return tmp;
650 }
651 
652 static int peek_user_compat(struct task_struct *child,
653 			    addr_t addr, addr_t data)
654 {
655 	__u32 tmp;
656 
657 	if (!is_compat_task() || (addr & 3) || addr > sizeof(struct user) - 3)
658 		return -EIO;
659 
660 	tmp = __peek_user_compat(child, addr);
661 	return put_user(tmp, (__u32 __user *) data);
662 }
663 
664 /*
665  * Same as poke_user_per but for a 31 bit program.
666  */
667 static inline void __poke_user_per_compat(struct task_struct *child,
668 					  addr_t addr, __u32 data)
669 {
670 	struct compat_per_struct_kernel *dummy32 = NULL;
671 
672 	if (addr == (addr_t) &dummy32->cr9)
673 		/* PER event mask of the user specified per set. */
674 		child->thread.per_user.control =
675 			data & (PER_EVENT_MASK | PER_CONTROL_MASK);
676 	else if (addr == (addr_t) &dummy32->starting_addr)
677 		/* Starting address of the user specified per set. */
678 		child->thread.per_user.start = data;
679 	else if (addr == (addr_t) &dummy32->ending_addr)
680 		/* Ending address of the user specified per set. */
681 		child->thread.per_user.end = data;
682 }
683 
684 /*
685  * Same as poke_user but for a 31 bit program.
686  */
687 static int __poke_user_compat(struct task_struct *child,
688 			      addr_t addr, addr_t data)
689 {
690 	struct compat_user *dummy32 = NULL;
691 	__u32 tmp = (__u32) data;
692 	addr_t offset;
693 
694 	if (addr < (addr_t) &dummy32->regs.acrs) {
695 		struct pt_regs *regs = task_pt_regs(child);
696 		/*
697 		 * psw, gprs, acrs and orig_gpr2 are stored on the stack
698 		 */
699 		if (addr == (addr_t) &dummy32->regs.psw.mask) {
700 			__u32 mask = PSW32_MASK_USER;
701 
702 			mask |= is_ri_task(child) ? PSW32_MASK_RI : 0;
703 			/* Build a 64 bit psw mask from 31 bit mask. */
704 			if ((tmp ^ PSW32_USER_BITS) & ~mask)
705 				/* Invalid psw mask. */
706 				return -EINVAL;
707 			if ((data & PSW32_MASK_ASC) == PSW32_ASC_HOME)
708 				/* Invalid address-space-control bits */
709 				return -EINVAL;
710 			regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
711 				(regs->psw.mask & PSW_MASK_BA) |
712 				(__u64)(tmp & mask) << 32;
713 		} else if (addr == (addr_t) &dummy32->regs.psw.addr) {
714 			/* Build a 64 bit psw address from 31 bit address. */
715 			regs->psw.addr = (__u64) tmp & PSW32_ADDR_INSN;
716 			/* Transfer 31 bit amode bit to psw mask. */
717 			regs->psw.mask = (regs->psw.mask & ~PSW_MASK_BA) |
718 				(__u64)(tmp & PSW32_ADDR_AMODE);
719 		} else {
720 			/* gpr 0-15 */
721 			*(__u32*)((addr_t) &regs->psw + addr*2 + 4) = tmp;
722 		}
723 	} else if (addr < (addr_t) (&dummy32->regs.orig_gpr2)) {
724 		/*
725 		 * access registers are stored in the thread structure
726 		 */
727 		offset = addr - (addr_t) &dummy32->regs.acrs;
728 		*(__u32*)((addr_t) &child->thread.acrs + offset) = tmp;
729 
730 	} else if (addr == (addr_t) (&dummy32->regs.orig_gpr2)) {
731 		/*
732 		 * orig_gpr2 is stored on the kernel stack
733 		 */
734 		*(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4) = tmp;
735 
736 	} else if (addr < (addr_t) &dummy32->regs.fp_regs) {
737 		/*
738 		 * prevent writess of padding hole between
739 		 * orig_gpr2 and fp_regs on s390.
740 		 */
741 		return 0;
742 
743 	} else if (addr == (addr_t) &dummy32->regs.fp_regs.fpc) {
744 		/*
745 		 * floating point control reg. is in the thread structure
746 		 */
747 		if (test_fp_ctl(tmp))
748 			return -EINVAL;
749 		child->thread.fp_regs.fpc = data;
750 
751 	} else if (addr < (addr_t) (&dummy32->regs.fp_regs + 1)) {
752 		/*
753 		 * floating point regs. are either in child->thread.fp_regs
754 		 * or the child->thread.vxrs array
755 		 */
756 		offset = addr - (addr_t) &dummy32->regs.fp_regs.fprs;
757 		if (child->thread.vxrs)
758 			*(__u32 *)((addr_t)
759 				child->thread.vxrs + 2*offset) = tmp;
760 		else
761 			*(__u32 *)((addr_t)
762 				&child->thread.fp_regs.fprs + offset) = tmp;
763 
764 	} else if (addr < (addr_t) (&dummy32->regs.per_info + 1)) {
765 		/*
766 		 * Handle access to the per_info structure.
767 		 */
768 		addr -= (addr_t) &dummy32->regs.per_info;
769 		__poke_user_per_compat(child, addr, data);
770 	}
771 
772 	return 0;
773 }
774 
775 static int poke_user_compat(struct task_struct *child,
776 			    addr_t addr, addr_t data)
777 {
778 	if (!is_compat_task() || (addr & 3) ||
779 	    addr > sizeof(struct compat_user) - 3)
780 		return -EIO;
781 
782 	return __poke_user_compat(child, addr, data);
783 }
784 
785 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
786 			compat_ulong_t caddr, compat_ulong_t cdata)
787 {
788 	unsigned long addr = caddr;
789 	unsigned long data = cdata;
790 	compat_ptrace_area parea;
791 	int copied, ret;
792 
793 	switch (request) {
794 	case PTRACE_PEEKUSR:
795 		/* read the word at location addr in the USER area. */
796 		return peek_user_compat(child, addr, data);
797 
798 	case PTRACE_POKEUSR:
799 		/* write the word at location addr in the USER area */
800 		return poke_user_compat(child, addr, data);
801 
802 	case PTRACE_PEEKUSR_AREA:
803 	case PTRACE_POKEUSR_AREA:
804 		if (copy_from_user(&parea, (void __force __user *) addr,
805 							sizeof(parea)))
806 			return -EFAULT;
807 		addr = parea.kernel_addr;
808 		data = parea.process_addr;
809 		copied = 0;
810 		while (copied < parea.len) {
811 			if (request == PTRACE_PEEKUSR_AREA)
812 				ret = peek_user_compat(child, addr, data);
813 			else {
814 				__u32 utmp;
815 				if (get_user(utmp,
816 					     (__u32 __force __user *) data))
817 					return -EFAULT;
818 				ret = poke_user_compat(child, addr, utmp);
819 			}
820 			if (ret)
821 				return ret;
822 			addr += sizeof(unsigned int);
823 			data += sizeof(unsigned int);
824 			copied += sizeof(unsigned int);
825 		}
826 		return 0;
827 	case PTRACE_GET_LAST_BREAK:
828 		put_user(task_thread_info(child)->last_break,
829 			 (unsigned int __user *) data);
830 		return 0;
831 	}
832 	return compat_ptrace_request(child, request, addr, data);
833 }
834 #endif
835 
836 asmlinkage long do_syscall_trace_enter(struct pt_regs *regs)
837 {
838 	long ret = 0;
839 
840 	/* Do the secure computing check first. */
841 	if (secure_computing()) {
842 		/* seccomp failures shouldn't expose any additional code. */
843 		ret = -1;
844 		goto out;
845 	}
846 
847 	/*
848 	 * The sysc_tracesys code in entry.S stored the system
849 	 * call number to gprs[2].
850 	 */
851 	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
852 	    (tracehook_report_syscall_entry(regs) ||
853 	     regs->gprs[2] >= NR_syscalls)) {
854 		/*
855 		 * Tracing decided this syscall should not happen or the
856 		 * debugger stored an invalid system call number. Skip
857 		 * the system call and the system call restart handling.
858 		 */
859 		clear_pt_regs_flag(regs, PIF_SYSCALL);
860 		ret = -1;
861 	}
862 
863 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
864 		trace_sys_enter(regs, regs->gprs[2]);
865 
866 	audit_syscall_entry(regs->gprs[2], regs->orig_gpr2,
867 			    regs->gprs[3], regs->gprs[4],
868 			    regs->gprs[5]);
869 out:
870 	return ret ?: regs->gprs[2];
871 }
872 
873 asmlinkage void do_syscall_trace_exit(struct pt_regs *regs)
874 {
875 	audit_syscall_exit(regs);
876 
877 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
878 		trace_sys_exit(regs, regs->gprs[2]);
879 
880 	if (test_thread_flag(TIF_SYSCALL_TRACE))
881 		tracehook_report_syscall_exit(regs, 0);
882 }
883 
884 /*
885  * user_regset definitions.
886  */
887 
888 static int s390_regs_get(struct task_struct *target,
889 			 const struct user_regset *regset,
890 			 unsigned int pos, unsigned int count,
891 			 void *kbuf, void __user *ubuf)
892 {
893 	if (target == current)
894 		save_access_regs(target->thread.acrs);
895 
896 	if (kbuf) {
897 		unsigned long *k = kbuf;
898 		while (count > 0) {
899 			*k++ = __peek_user(target, pos);
900 			count -= sizeof(*k);
901 			pos += sizeof(*k);
902 		}
903 	} else {
904 		unsigned long __user *u = ubuf;
905 		while (count > 0) {
906 			if (__put_user(__peek_user(target, pos), u++))
907 				return -EFAULT;
908 			count -= sizeof(*u);
909 			pos += sizeof(*u);
910 		}
911 	}
912 	return 0;
913 }
914 
915 static int s390_regs_set(struct task_struct *target,
916 			 const struct user_regset *regset,
917 			 unsigned int pos, unsigned int count,
918 			 const void *kbuf, const void __user *ubuf)
919 {
920 	int rc = 0;
921 
922 	if (target == current)
923 		save_access_regs(target->thread.acrs);
924 
925 	if (kbuf) {
926 		const unsigned long *k = kbuf;
927 		while (count > 0 && !rc) {
928 			rc = __poke_user(target, pos, *k++);
929 			count -= sizeof(*k);
930 			pos += sizeof(*k);
931 		}
932 	} else {
933 		const unsigned long  __user *u = ubuf;
934 		while (count > 0 && !rc) {
935 			unsigned long word;
936 			rc = __get_user(word, u++);
937 			if (rc)
938 				break;
939 			rc = __poke_user(target, pos, word);
940 			count -= sizeof(*u);
941 			pos += sizeof(*u);
942 		}
943 	}
944 
945 	if (rc == 0 && target == current)
946 		restore_access_regs(target->thread.acrs);
947 
948 	return rc;
949 }
950 
951 static int s390_fpregs_get(struct task_struct *target,
952 			   const struct user_regset *regset, unsigned int pos,
953 			   unsigned int count, void *kbuf, void __user *ubuf)
954 {
955 	if (target == current) {
956 		save_fp_ctl(&target->thread.fp_regs.fpc);
957 		save_fp_regs(target->thread.fp_regs.fprs);
958 	} else if (target->thread.vxrs) {
959 		int i;
960 
961 		for (i = 0; i < __NUM_VXRS_LOW; i++)
962 			target->thread.fp_regs.fprs[i] =
963 				*(freg_t *)(target->thread.vxrs + i);
964 	}
965 	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
966 				   &target->thread.fp_regs, 0, -1);
967 }
968 
969 static int s390_fpregs_set(struct task_struct *target,
970 			   const struct user_regset *regset, unsigned int pos,
971 			   unsigned int count, const void *kbuf,
972 			   const void __user *ubuf)
973 {
974 	int rc = 0;
975 
976 	if (target == current) {
977 		save_fp_ctl(&target->thread.fp_regs.fpc);
978 		save_fp_regs(target->thread.fp_regs.fprs);
979 	}
980 
981 	/* If setting FPC, must validate it first. */
982 	if (count > 0 && pos < offsetof(s390_fp_regs, fprs)) {
983 		u32 ufpc[2] = { target->thread.fp_regs.fpc, 0 };
984 		rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ufpc,
985 					0, offsetof(s390_fp_regs, fprs));
986 		if (rc)
987 			return rc;
988 		if (ufpc[1] != 0 || test_fp_ctl(ufpc[0]))
989 			return -EINVAL;
990 		target->thread.fp_regs.fpc = ufpc[0];
991 	}
992 
993 	if (rc == 0 && count > 0)
994 		rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
995 					target->thread.fp_regs.fprs,
996 					offsetof(s390_fp_regs, fprs), -1);
997 
998 	if (rc == 0) {
999 		if (target == current) {
1000 			restore_fp_ctl(&target->thread.fp_regs.fpc);
1001 			restore_fp_regs(target->thread.fp_regs.fprs);
1002 		} else if (target->thread.vxrs) {
1003 			int i;
1004 
1005 			for (i = 0; i < __NUM_VXRS_LOW; i++)
1006 				*(freg_t *)(target->thread.vxrs + i) =
1007 					target->thread.fp_regs.fprs[i];
1008 		}
1009 	}
1010 
1011 	return rc;
1012 }
1013 
1014 static int s390_last_break_get(struct task_struct *target,
1015 			       const struct user_regset *regset,
1016 			       unsigned int pos, unsigned int count,
1017 			       void *kbuf, void __user *ubuf)
1018 {
1019 	if (count > 0) {
1020 		if (kbuf) {
1021 			unsigned long *k = kbuf;
1022 			*k = task_thread_info(target)->last_break;
1023 		} else {
1024 			unsigned long  __user *u = ubuf;
1025 			if (__put_user(task_thread_info(target)->last_break, u))
1026 				return -EFAULT;
1027 		}
1028 	}
1029 	return 0;
1030 }
1031 
1032 static int s390_last_break_set(struct task_struct *target,
1033 			       const struct user_regset *regset,
1034 			       unsigned int pos, unsigned int count,
1035 			       const void *kbuf, const void __user *ubuf)
1036 {
1037 	return 0;
1038 }
1039 
1040 static int s390_tdb_get(struct task_struct *target,
1041 			const struct user_regset *regset,
1042 			unsigned int pos, unsigned int count,
1043 			void *kbuf, void __user *ubuf)
1044 {
1045 	struct pt_regs *regs = task_pt_regs(target);
1046 	unsigned char *data;
1047 
1048 	if (!(regs->int_code & 0x200))
1049 		return -ENODATA;
1050 	data = target->thread.trap_tdb;
1051 	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, data, 0, 256);
1052 }
1053 
1054 static int s390_tdb_set(struct task_struct *target,
1055 			const struct user_regset *regset,
1056 			unsigned int pos, unsigned int count,
1057 			const void *kbuf, const void __user *ubuf)
1058 {
1059 	return 0;
1060 }
1061 
1062 static int s390_vxrs_low_get(struct task_struct *target,
1063 			     const struct user_regset *regset,
1064 			     unsigned int pos, unsigned int count,
1065 			     void *kbuf, void __user *ubuf)
1066 {
1067 	__u64 vxrs[__NUM_VXRS_LOW];
1068 	int i;
1069 
1070 	if (!MACHINE_HAS_VX)
1071 		return -ENODEV;
1072 	if (target->thread.vxrs) {
1073 		if (target == current)
1074 			save_vx_regs(target->thread.vxrs);
1075 		for (i = 0; i < __NUM_VXRS_LOW; i++)
1076 			vxrs[i] = *((__u64 *)(target->thread.vxrs + i) + 1);
1077 	} else
1078 		memset(vxrs, 0, sizeof(vxrs));
1079 	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, vxrs, 0, -1);
1080 }
1081 
1082 static int s390_vxrs_low_set(struct task_struct *target,
1083 			     const struct user_regset *regset,
1084 			     unsigned int pos, unsigned int count,
1085 			     const void *kbuf, const void __user *ubuf)
1086 {
1087 	__u64 vxrs[__NUM_VXRS_LOW];
1088 	int i, rc;
1089 
1090 	if (!MACHINE_HAS_VX)
1091 		return -ENODEV;
1092 	if (!target->thread.vxrs) {
1093 		rc = alloc_vector_registers(target);
1094 		if (rc)
1095 			return rc;
1096 	} else if (target == current)
1097 		save_vx_regs(target->thread.vxrs);
1098 
1099 	rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, vxrs, 0, -1);
1100 	if (rc == 0) {
1101 		for (i = 0; i < __NUM_VXRS_LOW; i++)
1102 			*((__u64 *)(target->thread.vxrs + i) + 1) = vxrs[i];
1103 		if (target == current)
1104 			restore_vx_regs(target->thread.vxrs);
1105 	}
1106 
1107 	return rc;
1108 }
1109 
1110 static int s390_vxrs_high_get(struct task_struct *target,
1111 			      const struct user_regset *regset,
1112 			      unsigned int pos, unsigned int count,
1113 			      void *kbuf, void __user *ubuf)
1114 {
1115 	__vector128 vxrs[__NUM_VXRS_HIGH];
1116 
1117 	if (!MACHINE_HAS_VX)
1118 		return -ENODEV;
1119 	if (target->thread.vxrs) {
1120 		if (target == current)
1121 			save_vx_regs(target->thread.vxrs);
1122 		memcpy(vxrs, target->thread.vxrs + __NUM_VXRS_LOW,
1123 		       sizeof(vxrs));
1124 	} else
1125 		memset(vxrs, 0, sizeof(vxrs));
1126 	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, vxrs, 0, -1);
1127 }
1128 
1129 static int s390_vxrs_high_set(struct task_struct *target,
1130 			      const struct user_regset *regset,
1131 			      unsigned int pos, unsigned int count,
1132 			      const void *kbuf, const void __user *ubuf)
1133 {
1134 	int rc;
1135 
1136 	if (!MACHINE_HAS_VX)
1137 		return -ENODEV;
1138 	if (!target->thread.vxrs) {
1139 		rc = alloc_vector_registers(target);
1140 		if (rc)
1141 			return rc;
1142 	} else if (target == current)
1143 		save_vx_regs(target->thread.vxrs);
1144 
1145 	rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
1146 				target->thread.vxrs + __NUM_VXRS_LOW, 0, -1);
1147 	if (rc == 0 && target == current)
1148 		restore_vx_regs(target->thread.vxrs);
1149 
1150 	return rc;
1151 }
1152 
1153 static int s390_system_call_get(struct task_struct *target,
1154 				const struct user_regset *regset,
1155 				unsigned int pos, unsigned int count,
1156 				void *kbuf, void __user *ubuf)
1157 {
1158 	unsigned int *data = &task_thread_info(target)->system_call;
1159 	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
1160 				   data, 0, sizeof(unsigned int));
1161 }
1162 
1163 static int s390_system_call_set(struct task_struct *target,
1164 				const struct user_regset *regset,
1165 				unsigned int pos, unsigned int count,
1166 				const void *kbuf, const void __user *ubuf)
1167 {
1168 	unsigned int *data = &task_thread_info(target)->system_call;
1169 	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
1170 				  data, 0, sizeof(unsigned int));
1171 }
1172 
1173 static const struct user_regset s390_regsets[] = {
1174 	{
1175 		.core_note_type = NT_PRSTATUS,
1176 		.n = sizeof(s390_regs) / sizeof(long),
1177 		.size = sizeof(long),
1178 		.align = sizeof(long),
1179 		.get = s390_regs_get,
1180 		.set = s390_regs_set,
1181 	},
1182 	{
1183 		.core_note_type = NT_PRFPREG,
1184 		.n = sizeof(s390_fp_regs) / sizeof(long),
1185 		.size = sizeof(long),
1186 		.align = sizeof(long),
1187 		.get = s390_fpregs_get,
1188 		.set = s390_fpregs_set,
1189 	},
1190 	{
1191 		.core_note_type = NT_S390_SYSTEM_CALL,
1192 		.n = 1,
1193 		.size = sizeof(unsigned int),
1194 		.align = sizeof(unsigned int),
1195 		.get = s390_system_call_get,
1196 		.set = s390_system_call_set,
1197 	},
1198 	{
1199 		.core_note_type = NT_S390_LAST_BREAK,
1200 		.n = 1,
1201 		.size = sizeof(long),
1202 		.align = sizeof(long),
1203 		.get = s390_last_break_get,
1204 		.set = s390_last_break_set,
1205 	},
1206 	{
1207 		.core_note_type = NT_S390_TDB,
1208 		.n = 1,
1209 		.size = 256,
1210 		.align = 1,
1211 		.get = s390_tdb_get,
1212 		.set = s390_tdb_set,
1213 	},
1214 	{
1215 		.core_note_type = NT_S390_VXRS_LOW,
1216 		.n = __NUM_VXRS_LOW,
1217 		.size = sizeof(__u64),
1218 		.align = sizeof(__u64),
1219 		.get = s390_vxrs_low_get,
1220 		.set = s390_vxrs_low_set,
1221 	},
1222 	{
1223 		.core_note_type = NT_S390_VXRS_HIGH,
1224 		.n = __NUM_VXRS_HIGH,
1225 		.size = sizeof(__vector128),
1226 		.align = sizeof(__vector128),
1227 		.get = s390_vxrs_high_get,
1228 		.set = s390_vxrs_high_set,
1229 	},
1230 };
1231 
1232 static const struct user_regset_view user_s390_view = {
1233 	.name = UTS_MACHINE,
1234 	.e_machine = EM_S390,
1235 	.regsets = s390_regsets,
1236 	.n = ARRAY_SIZE(s390_regsets)
1237 };
1238 
1239 #ifdef CONFIG_COMPAT
1240 static int s390_compat_regs_get(struct task_struct *target,
1241 				const struct user_regset *regset,
1242 				unsigned int pos, unsigned int count,
1243 				void *kbuf, void __user *ubuf)
1244 {
1245 	if (target == current)
1246 		save_access_regs(target->thread.acrs);
1247 
1248 	if (kbuf) {
1249 		compat_ulong_t *k = kbuf;
1250 		while (count > 0) {
1251 			*k++ = __peek_user_compat(target, pos);
1252 			count -= sizeof(*k);
1253 			pos += sizeof(*k);
1254 		}
1255 	} else {
1256 		compat_ulong_t __user *u = ubuf;
1257 		while (count > 0) {
1258 			if (__put_user(__peek_user_compat(target, pos), u++))
1259 				return -EFAULT;
1260 			count -= sizeof(*u);
1261 			pos += sizeof(*u);
1262 		}
1263 	}
1264 	return 0;
1265 }
1266 
1267 static int s390_compat_regs_set(struct task_struct *target,
1268 				const struct user_regset *regset,
1269 				unsigned int pos, unsigned int count,
1270 				const void *kbuf, const void __user *ubuf)
1271 {
1272 	int rc = 0;
1273 
1274 	if (target == current)
1275 		save_access_regs(target->thread.acrs);
1276 
1277 	if (kbuf) {
1278 		const compat_ulong_t *k = kbuf;
1279 		while (count > 0 && !rc) {
1280 			rc = __poke_user_compat(target, pos, *k++);
1281 			count -= sizeof(*k);
1282 			pos += sizeof(*k);
1283 		}
1284 	} else {
1285 		const compat_ulong_t  __user *u = ubuf;
1286 		while (count > 0 && !rc) {
1287 			compat_ulong_t word;
1288 			rc = __get_user(word, u++);
1289 			if (rc)
1290 				break;
1291 			rc = __poke_user_compat(target, pos, word);
1292 			count -= sizeof(*u);
1293 			pos += sizeof(*u);
1294 		}
1295 	}
1296 
1297 	if (rc == 0 && target == current)
1298 		restore_access_regs(target->thread.acrs);
1299 
1300 	return rc;
1301 }
1302 
1303 static int s390_compat_regs_high_get(struct task_struct *target,
1304 				     const struct user_regset *regset,
1305 				     unsigned int pos, unsigned int count,
1306 				     void *kbuf, void __user *ubuf)
1307 {
1308 	compat_ulong_t *gprs_high;
1309 
1310 	gprs_high = (compat_ulong_t *)
1311 		&task_pt_regs(target)->gprs[pos / sizeof(compat_ulong_t)];
1312 	if (kbuf) {
1313 		compat_ulong_t *k = kbuf;
1314 		while (count > 0) {
1315 			*k++ = *gprs_high;
1316 			gprs_high += 2;
1317 			count -= sizeof(*k);
1318 		}
1319 	} else {
1320 		compat_ulong_t __user *u = ubuf;
1321 		while (count > 0) {
1322 			if (__put_user(*gprs_high, u++))
1323 				return -EFAULT;
1324 			gprs_high += 2;
1325 			count -= sizeof(*u);
1326 		}
1327 	}
1328 	return 0;
1329 }
1330 
1331 static int s390_compat_regs_high_set(struct task_struct *target,
1332 				     const struct user_regset *regset,
1333 				     unsigned int pos, unsigned int count,
1334 				     const void *kbuf, const void __user *ubuf)
1335 {
1336 	compat_ulong_t *gprs_high;
1337 	int rc = 0;
1338 
1339 	gprs_high = (compat_ulong_t *)
1340 		&task_pt_regs(target)->gprs[pos / sizeof(compat_ulong_t)];
1341 	if (kbuf) {
1342 		const compat_ulong_t *k = kbuf;
1343 		while (count > 0) {
1344 			*gprs_high = *k++;
1345 			*gprs_high += 2;
1346 			count -= sizeof(*k);
1347 		}
1348 	} else {
1349 		const compat_ulong_t  __user *u = ubuf;
1350 		while (count > 0 && !rc) {
1351 			unsigned long word;
1352 			rc = __get_user(word, u++);
1353 			if (rc)
1354 				break;
1355 			*gprs_high = word;
1356 			*gprs_high += 2;
1357 			count -= sizeof(*u);
1358 		}
1359 	}
1360 
1361 	return rc;
1362 }
1363 
1364 static int s390_compat_last_break_get(struct task_struct *target,
1365 				      const struct user_regset *regset,
1366 				      unsigned int pos, unsigned int count,
1367 				      void *kbuf, void __user *ubuf)
1368 {
1369 	compat_ulong_t last_break;
1370 
1371 	if (count > 0) {
1372 		last_break = task_thread_info(target)->last_break;
1373 		if (kbuf) {
1374 			unsigned long *k = kbuf;
1375 			*k = last_break;
1376 		} else {
1377 			unsigned long  __user *u = ubuf;
1378 			if (__put_user(last_break, u))
1379 				return -EFAULT;
1380 		}
1381 	}
1382 	return 0;
1383 }
1384 
1385 static int s390_compat_last_break_set(struct task_struct *target,
1386 				      const struct user_regset *regset,
1387 				      unsigned int pos, unsigned int count,
1388 				      const void *kbuf, const void __user *ubuf)
1389 {
1390 	return 0;
1391 }
1392 
1393 static const struct user_regset s390_compat_regsets[] = {
1394 	{
1395 		.core_note_type = NT_PRSTATUS,
1396 		.n = sizeof(s390_compat_regs) / sizeof(compat_long_t),
1397 		.size = sizeof(compat_long_t),
1398 		.align = sizeof(compat_long_t),
1399 		.get = s390_compat_regs_get,
1400 		.set = s390_compat_regs_set,
1401 	},
1402 	{
1403 		.core_note_type = NT_PRFPREG,
1404 		.n = sizeof(s390_fp_regs) / sizeof(compat_long_t),
1405 		.size = sizeof(compat_long_t),
1406 		.align = sizeof(compat_long_t),
1407 		.get = s390_fpregs_get,
1408 		.set = s390_fpregs_set,
1409 	},
1410 	{
1411 		.core_note_type = NT_S390_SYSTEM_CALL,
1412 		.n = 1,
1413 		.size = sizeof(compat_uint_t),
1414 		.align = sizeof(compat_uint_t),
1415 		.get = s390_system_call_get,
1416 		.set = s390_system_call_set,
1417 	},
1418 	{
1419 		.core_note_type = NT_S390_LAST_BREAK,
1420 		.n = 1,
1421 		.size = sizeof(long),
1422 		.align = sizeof(long),
1423 		.get = s390_compat_last_break_get,
1424 		.set = s390_compat_last_break_set,
1425 	},
1426 	{
1427 		.core_note_type = NT_S390_TDB,
1428 		.n = 1,
1429 		.size = 256,
1430 		.align = 1,
1431 		.get = s390_tdb_get,
1432 		.set = s390_tdb_set,
1433 	},
1434 	{
1435 		.core_note_type = NT_S390_VXRS_LOW,
1436 		.n = __NUM_VXRS_LOW,
1437 		.size = sizeof(__u64),
1438 		.align = sizeof(__u64),
1439 		.get = s390_vxrs_low_get,
1440 		.set = s390_vxrs_low_set,
1441 	},
1442 	{
1443 		.core_note_type = NT_S390_VXRS_HIGH,
1444 		.n = __NUM_VXRS_HIGH,
1445 		.size = sizeof(__vector128),
1446 		.align = sizeof(__vector128),
1447 		.get = s390_vxrs_high_get,
1448 		.set = s390_vxrs_high_set,
1449 	},
1450 	{
1451 		.core_note_type = NT_S390_HIGH_GPRS,
1452 		.n = sizeof(s390_compat_regs_high) / sizeof(compat_long_t),
1453 		.size = sizeof(compat_long_t),
1454 		.align = sizeof(compat_long_t),
1455 		.get = s390_compat_regs_high_get,
1456 		.set = s390_compat_regs_high_set,
1457 	},
1458 };
1459 
1460 static const struct user_regset_view user_s390_compat_view = {
1461 	.name = "s390",
1462 	.e_machine = EM_S390,
1463 	.regsets = s390_compat_regsets,
1464 	.n = ARRAY_SIZE(s390_compat_regsets)
1465 };
1466 #endif
1467 
1468 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
1469 {
1470 #ifdef CONFIG_COMPAT
1471 	if (test_tsk_thread_flag(task, TIF_31BIT))
1472 		return &user_s390_compat_view;
1473 #endif
1474 	return &user_s390_view;
1475 }
1476 
1477 static const char *gpr_names[NUM_GPRS] = {
1478 	"r0", "r1",  "r2",  "r3",  "r4",  "r5",  "r6",  "r7",
1479 	"r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
1480 };
1481 
1482 unsigned long regs_get_register(struct pt_regs *regs, unsigned int offset)
1483 {
1484 	if (offset >= NUM_GPRS)
1485 		return 0;
1486 	return regs->gprs[offset];
1487 }
1488 
1489 int regs_query_register_offset(const char *name)
1490 {
1491 	unsigned long offset;
1492 
1493 	if (!name || *name != 'r')
1494 		return -EINVAL;
1495 	if (kstrtoul(name + 1, 10, &offset))
1496 		return -EINVAL;
1497 	if (offset >= NUM_GPRS)
1498 		return -EINVAL;
1499 	return offset;
1500 }
1501 
1502 const char *regs_query_register_name(unsigned int offset)
1503 {
1504 	if (offset >= NUM_GPRS)
1505 		return NULL;
1506 	return gpr_names[offset];
1507 }
1508 
1509 static int regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
1510 {
1511 	unsigned long ksp = kernel_stack_pointer(regs);
1512 
1513 	return (addr & ~(THREAD_SIZE - 1)) == (ksp & ~(THREAD_SIZE - 1));
1514 }
1515 
1516 /**
1517  * regs_get_kernel_stack_nth() - get Nth entry of the stack
1518  * @regs:pt_regs which contains kernel stack pointer.
1519  * @n:stack entry number.
1520  *
1521  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
1522  * is specifined by @regs. If the @n th entry is NOT in the kernel stack,
1523  * this returns 0.
1524  */
1525 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
1526 {
1527 	unsigned long addr;
1528 
1529 	addr = kernel_stack_pointer(regs) + n * sizeof(long);
1530 	if (!regs_within_kernel_stack(regs, addr))
1531 		return 0;
1532 	return *(unsigned long *)addr;
1533 }
1534