xref: /openbmc/linux/arch/s390/kernel/ptrace.c (revision 31a254f6)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  Ptrace user space interface.
4  *
5  *    Copyright IBM Corp. 1999, 2010
6  *    Author(s): Denis Joseph Barrow
7  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
8  */
9 
10 #include "asm/ptrace.h"
11 #include <linux/kernel.h>
12 #include <linux/sched.h>
13 #include <linux/sched/task_stack.h>
14 #include <linux/mm.h>
15 #include <linux/smp.h>
16 #include <linux/errno.h>
17 #include <linux/ptrace.h>
18 #include <linux/user.h>
19 #include <linux/security.h>
20 #include <linux/audit.h>
21 #include <linux/signal.h>
22 #include <linux/elf.h>
23 #include <linux/regset.h>
24 #include <linux/seccomp.h>
25 #include <linux/compat.h>
26 #include <trace/syscall.h>
27 #include <asm/page.h>
28 #include <linux/uaccess.h>
29 #include <asm/unistd.h>
30 #include <asm/switch_to.h>
31 #include <asm/runtime_instr.h>
32 #include <asm/facility.h>
33 
34 #include "entry.h"
35 
36 #ifdef CONFIG_COMPAT
37 #include "compat_ptrace.h"
38 #endif
39 
40 void update_cr_regs(struct task_struct *task)
41 {
42 	struct pt_regs *regs = task_pt_regs(task);
43 	struct thread_struct *thread = &task->thread;
44 	struct per_regs old, new;
45 	union ctlreg0 cr0_old, cr0_new;
46 	union ctlreg2 cr2_old, cr2_new;
47 	int cr0_changed, cr2_changed;
48 
49 	__ctl_store(cr0_old.val, 0, 0);
50 	__ctl_store(cr2_old.val, 2, 2);
51 	cr0_new = cr0_old;
52 	cr2_new = cr2_old;
53 	/* Take care of the enable/disable of transactional execution. */
54 	if (MACHINE_HAS_TE) {
55 		/* Set or clear transaction execution TXC bit 8. */
56 		cr0_new.tcx = 1;
57 		if (task->thread.per_flags & PER_FLAG_NO_TE)
58 			cr0_new.tcx = 0;
59 		/* Set or clear transaction execution TDC bits 62 and 63. */
60 		cr2_new.tdc = 0;
61 		if (task->thread.per_flags & PER_FLAG_TE_ABORT_RAND) {
62 			if (task->thread.per_flags & PER_FLAG_TE_ABORT_RAND_TEND)
63 				cr2_new.tdc = 1;
64 			else
65 				cr2_new.tdc = 2;
66 		}
67 	}
68 	/* Take care of enable/disable of guarded storage. */
69 	if (MACHINE_HAS_GS) {
70 		cr2_new.gse = 0;
71 		if (task->thread.gs_cb)
72 			cr2_new.gse = 1;
73 	}
74 	/* Load control register 0/2 iff changed */
75 	cr0_changed = cr0_new.val != cr0_old.val;
76 	cr2_changed = cr2_new.val != cr2_old.val;
77 	if (cr0_changed)
78 		__ctl_load(cr0_new.val, 0, 0);
79 	if (cr2_changed)
80 		__ctl_load(cr2_new.val, 2, 2);
81 	/* Copy user specified PER registers */
82 	new.control = thread->per_user.control;
83 	new.start = thread->per_user.start;
84 	new.end = thread->per_user.end;
85 
86 	/* merge TIF_SINGLE_STEP into user specified PER registers. */
87 	if (test_tsk_thread_flag(task, TIF_SINGLE_STEP) ||
88 	    test_tsk_thread_flag(task, TIF_UPROBE_SINGLESTEP)) {
89 		if (test_tsk_thread_flag(task, TIF_BLOCK_STEP))
90 			new.control |= PER_EVENT_BRANCH;
91 		else
92 			new.control |= PER_EVENT_IFETCH;
93 		new.control |= PER_CONTROL_SUSPENSION;
94 		new.control |= PER_EVENT_TRANSACTION_END;
95 		if (test_tsk_thread_flag(task, TIF_UPROBE_SINGLESTEP))
96 			new.control |= PER_EVENT_IFETCH;
97 		new.start = 0;
98 		new.end = -1UL;
99 	}
100 
101 	/* Take care of the PER enablement bit in the PSW. */
102 	if (!(new.control & PER_EVENT_MASK)) {
103 		regs->psw.mask &= ~PSW_MASK_PER;
104 		return;
105 	}
106 	regs->psw.mask |= PSW_MASK_PER;
107 	__ctl_store(old, 9, 11);
108 	if (memcmp(&new, &old, sizeof(struct per_regs)) != 0)
109 		__ctl_load(new, 9, 11);
110 }
111 
112 void user_enable_single_step(struct task_struct *task)
113 {
114 	clear_tsk_thread_flag(task, TIF_BLOCK_STEP);
115 	set_tsk_thread_flag(task, TIF_SINGLE_STEP);
116 }
117 
118 void user_disable_single_step(struct task_struct *task)
119 {
120 	clear_tsk_thread_flag(task, TIF_BLOCK_STEP);
121 	clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
122 }
123 
124 void user_enable_block_step(struct task_struct *task)
125 {
126 	set_tsk_thread_flag(task, TIF_SINGLE_STEP);
127 	set_tsk_thread_flag(task, TIF_BLOCK_STEP);
128 }
129 
130 /*
131  * Called by kernel/ptrace.c when detaching..
132  *
133  * Clear all debugging related fields.
134  */
135 void ptrace_disable(struct task_struct *task)
136 {
137 	memset(&task->thread.per_user, 0, sizeof(task->thread.per_user));
138 	memset(&task->thread.per_event, 0, sizeof(task->thread.per_event));
139 	clear_tsk_thread_flag(task, TIF_SINGLE_STEP);
140 	clear_tsk_thread_flag(task, TIF_PER_TRAP);
141 	task->thread.per_flags = 0;
142 }
143 
144 #define __ADDR_MASK 7
145 
146 static inline unsigned long __peek_user_per(struct task_struct *child,
147 					    addr_t addr)
148 {
149 	if (addr == offsetof(struct per_struct_kernel, cr9))
150 		/* Control bits of the active per set. */
151 		return test_thread_flag(TIF_SINGLE_STEP) ?
152 			PER_EVENT_IFETCH : child->thread.per_user.control;
153 	else if (addr == offsetof(struct per_struct_kernel, cr10))
154 		/* Start address of the active per set. */
155 		return test_thread_flag(TIF_SINGLE_STEP) ?
156 			0 : child->thread.per_user.start;
157 	else if (addr == offsetof(struct per_struct_kernel, cr11))
158 		/* End address of the active per set. */
159 		return test_thread_flag(TIF_SINGLE_STEP) ?
160 			-1UL : child->thread.per_user.end;
161 	else if (addr == offsetof(struct per_struct_kernel, bits))
162 		/* Single-step bit. */
163 		return test_thread_flag(TIF_SINGLE_STEP) ?
164 			(1UL << (BITS_PER_LONG - 1)) : 0;
165 	else if (addr == offsetof(struct per_struct_kernel, starting_addr))
166 		/* Start address of the user specified per set. */
167 		return child->thread.per_user.start;
168 	else if (addr == offsetof(struct per_struct_kernel, ending_addr))
169 		/* End address of the user specified per set. */
170 		return child->thread.per_user.end;
171 	else if (addr == offsetof(struct per_struct_kernel, perc_atmid))
172 		/* PER code, ATMID and AI of the last PER trap */
173 		return (unsigned long)
174 			child->thread.per_event.cause << (BITS_PER_LONG - 16);
175 	else if (addr == offsetof(struct per_struct_kernel, address))
176 		/* Address of the last PER trap */
177 		return child->thread.per_event.address;
178 	else if (addr == offsetof(struct per_struct_kernel, access_id))
179 		/* Access id of the last PER trap */
180 		return (unsigned long)
181 			child->thread.per_event.paid << (BITS_PER_LONG - 8);
182 	return 0;
183 }
184 
185 /*
186  * Read the word at offset addr from the user area of a process. The
187  * trouble here is that the information is littered over different
188  * locations. The process registers are found on the kernel stack,
189  * the floating point stuff and the trace settings are stored in
190  * the task structure. In addition the different structures in
191  * struct user contain pad bytes that should be read as zeroes.
192  * Lovely...
193  */
194 static unsigned long __peek_user(struct task_struct *child, addr_t addr)
195 {
196 	addr_t offset, tmp;
197 
198 	if (addr < offsetof(struct user, regs.acrs)) {
199 		/*
200 		 * psw and gprs are stored on the stack
201 		 */
202 		tmp = *(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr);
203 		if (addr == offsetof(struct user, regs.psw.mask)) {
204 			/* Return a clean psw mask. */
205 			tmp &= PSW_MASK_USER | PSW_MASK_RI;
206 			tmp |= PSW_USER_BITS;
207 		}
208 
209 	} else if (addr < offsetof(struct user, regs.orig_gpr2)) {
210 		/*
211 		 * access registers are stored in the thread structure
212 		 */
213 		offset = addr - offsetof(struct user, regs.acrs);
214 		/*
215 		 * Very special case: old & broken 64 bit gdb reading
216 		 * from acrs[15]. Result is a 64 bit value. Read the
217 		 * 32 bit acrs[15] value and shift it by 32. Sick...
218 		 */
219 		if (addr == offsetof(struct user, regs.acrs[15]))
220 			tmp = ((unsigned long) child->thread.acrs[15]) << 32;
221 		else
222 			tmp = *(addr_t *)((addr_t) &child->thread.acrs + offset);
223 
224 	} else if (addr == offsetof(struct user, regs.orig_gpr2)) {
225 		/*
226 		 * orig_gpr2 is stored on the kernel stack
227 		 */
228 		tmp = (addr_t) task_pt_regs(child)->orig_gpr2;
229 
230 	} else if (addr < offsetof(struct user, regs.fp_regs)) {
231 		/*
232 		 * prevent reads of padding hole between
233 		 * orig_gpr2 and fp_regs on s390.
234 		 */
235 		tmp = 0;
236 
237 	} else if (addr == offsetof(struct user, regs.fp_regs.fpc)) {
238 		/*
239 		 * floating point control reg. is in the thread structure
240 		 */
241 		tmp = child->thread.fpu.fpc;
242 		tmp <<= BITS_PER_LONG - 32;
243 
244 	} else if (addr < offsetof(struct user, regs.fp_regs) + sizeof(s390_fp_regs)) {
245 		/*
246 		 * floating point regs. are either in child->thread.fpu
247 		 * or the child->thread.fpu.vxrs array
248 		 */
249 		offset = addr - offsetof(struct user, regs.fp_regs.fprs);
250 		if (MACHINE_HAS_VX)
251 			tmp = *(addr_t *)
252 			       ((addr_t) child->thread.fpu.vxrs + 2*offset);
253 		else
254 			tmp = *(addr_t *)
255 			       ((addr_t) child->thread.fpu.fprs + offset);
256 
257 	} else if (addr < offsetof(struct user, regs.per_info) + sizeof(per_struct)) {
258 		/*
259 		 * Handle access to the per_info structure.
260 		 */
261 		addr -= offsetof(struct user, regs.per_info);
262 		tmp = __peek_user_per(child, addr);
263 
264 	} else
265 		tmp = 0;
266 
267 	return tmp;
268 }
269 
270 static int
271 peek_user(struct task_struct *child, addr_t addr, addr_t data)
272 {
273 	addr_t tmp, mask;
274 
275 	/*
276 	 * Stupid gdb peeks/pokes the access registers in 64 bit with
277 	 * an alignment of 4. Programmers from hell...
278 	 */
279 	mask = __ADDR_MASK;
280 	if (addr >= offsetof(struct user, regs.acrs) &&
281 	    addr < offsetof(struct user, regs.orig_gpr2))
282 		mask = 3;
283 	if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
284 		return -EIO;
285 
286 	tmp = __peek_user(child, addr);
287 	return put_user(tmp, (addr_t __user *) data);
288 }
289 
290 static inline void __poke_user_per(struct task_struct *child,
291 				   addr_t addr, addr_t data)
292 {
293 	/*
294 	 * There are only three fields in the per_info struct that the
295 	 * debugger user can write to.
296 	 * 1) cr9: the debugger wants to set a new PER event mask
297 	 * 2) starting_addr: the debugger wants to set a new starting
298 	 *    address to use with the PER event mask.
299 	 * 3) ending_addr: the debugger wants to set a new ending
300 	 *    address to use with the PER event mask.
301 	 * The user specified PER event mask and the start and end
302 	 * addresses are used only if single stepping is not in effect.
303 	 * Writes to any other field in per_info are ignored.
304 	 */
305 	if (addr == offsetof(struct per_struct_kernel, cr9))
306 		/* PER event mask of the user specified per set. */
307 		child->thread.per_user.control =
308 			data & (PER_EVENT_MASK | PER_CONTROL_MASK);
309 	else if (addr == offsetof(struct per_struct_kernel, starting_addr))
310 		/* Starting address of the user specified per set. */
311 		child->thread.per_user.start = data;
312 	else if (addr == offsetof(struct per_struct_kernel, ending_addr))
313 		/* Ending address of the user specified per set. */
314 		child->thread.per_user.end = data;
315 }
316 
317 /*
318  * Write a word to the user area of a process at location addr. This
319  * operation does have an additional problem compared to peek_user.
320  * Stores to the program status word and on the floating point
321  * control register needs to get checked for validity.
322  */
323 static int __poke_user(struct task_struct *child, addr_t addr, addr_t data)
324 {
325 	addr_t offset;
326 
327 
328 	if (addr < offsetof(struct user, regs.acrs)) {
329 		struct pt_regs *regs = task_pt_regs(child);
330 		/*
331 		 * psw and gprs are stored on the stack
332 		 */
333 		if (addr == offsetof(struct user, regs.psw.mask)) {
334 			unsigned long mask = PSW_MASK_USER;
335 
336 			mask |= is_ri_task(child) ? PSW_MASK_RI : 0;
337 			if ((data ^ PSW_USER_BITS) & ~mask)
338 				/* Invalid psw mask. */
339 				return -EINVAL;
340 			if ((data & PSW_MASK_ASC) == PSW_ASC_HOME)
341 				/* Invalid address-space-control bits */
342 				return -EINVAL;
343 			if ((data & PSW_MASK_EA) && !(data & PSW_MASK_BA))
344 				/* Invalid addressing mode bits */
345 				return -EINVAL;
346 		}
347 
348 		if (test_pt_regs_flag(regs, PIF_SYSCALL) &&
349 			addr == offsetof(struct user, regs.gprs[2])) {
350 			struct pt_regs *regs = task_pt_regs(child);
351 
352 			regs->int_code = 0x20000 | (data & 0xffff);
353 		}
354 		*(addr_t *)((addr_t) &regs->psw + addr) = data;
355 	} else if (addr < offsetof(struct user, regs.orig_gpr2)) {
356 		/*
357 		 * access registers are stored in the thread structure
358 		 */
359 		offset = addr - offsetof(struct user, regs.acrs);
360 		/*
361 		 * Very special case: old & broken 64 bit gdb writing
362 		 * to acrs[15] with a 64 bit value. Ignore the lower
363 		 * half of the value and write the upper 32 bit to
364 		 * acrs[15]. Sick...
365 		 */
366 		if (addr == offsetof(struct user, regs.acrs[15]))
367 			child->thread.acrs[15] = (unsigned int) (data >> 32);
368 		else
369 			*(addr_t *)((addr_t) &child->thread.acrs + offset) = data;
370 
371 	} else if (addr == offsetof(struct user, regs.orig_gpr2)) {
372 		/*
373 		 * orig_gpr2 is stored on the kernel stack
374 		 */
375 		task_pt_regs(child)->orig_gpr2 = data;
376 
377 	} else if (addr < offsetof(struct user, regs.fp_regs)) {
378 		/*
379 		 * prevent writes of padding hole between
380 		 * orig_gpr2 and fp_regs on s390.
381 		 */
382 		return 0;
383 
384 	} else if (addr == offsetof(struct user, regs.fp_regs.fpc)) {
385 		/*
386 		 * floating point control reg. is in the thread structure
387 		 */
388 		save_fpu_regs();
389 		if ((unsigned int) data != 0 ||
390 		    test_fp_ctl(data >> (BITS_PER_LONG - 32)))
391 			return -EINVAL;
392 		child->thread.fpu.fpc = data >> (BITS_PER_LONG - 32);
393 
394 	} else if (addr < offsetof(struct user, regs.fp_regs) + sizeof(s390_fp_regs)) {
395 		/*
396 		 * floating point regs. are either in child->thread.fpu
397 		 * or the child->thread.fpu.vxrs array
398 		 */
399 		offset = addr - offsetof(struct user, regs.fp_regs.fprs);
400 		if (MACHINE_HAS_VX)
401 			*(addr_t *)((addr_t)
402 				child->thread.fpu.vxrs + 2*offset) = data;
403 		else
404 			*(addr_t *)((addr_t)
405 				child->thread.fpu.fprs + offset) = data;
406 
407 	} else if (addr < offsetof(struct user, regs.per_info) + sizeof(per_struct)) {
408 		/*
409 		 * Handle access to the per_info structure.
410 		 */
411 		addr -= offsetof(struct user, regs.per_info);
412 		__poke_user_per(child, addr, data);
413 
414 	}
415 
416 	return 0;
417 }
418 
419 static int poke_user(struct task_struct *child, addr_t addr, addr_t data)
420 {
421 	addr_t mask;
422 
423 	/*
424 	 * Stupid gdb peeks/pokes the access registers in 64 bit with
425 	 * an alignment of 4. Programmers from hell indeed...
426 	 */
427 	mask = __ADDR_MASK;
428 	if (addr >= offsetof(struct user, regs.acrs) &&
429 	    addr < offsetof(struct user, regs.orig_gpr2))
430 		mask = 3;
431 	if ((addr & mask) || addr > sizeof(struct user) - __ADDR_MASK)
432 		return -EIO;
433 
434 	return __poke_user(child, addr, data);
435 }
436 
437 long arch_ptrace(struct task_struct *child, long request,
438 		 unsigned long addr, unsigned long data)
439 {
440 	ptrace_area parea;
441 	int copied, ret;
442 
443 	switch (request) {
444 	case PTRACE_PEEKUSR:
445 		/* read the word at location addr in the USER area. */
446 		return peek_user(child, addr, data);
447 
448 	case PTRACE_POKEUSR:
449 		/* write the word at location addr in the USER area */
450 		return poke_user(child, addr, data);
451 
452 	case PTRACE_PEEKUSR_AREA:
453 	case PTRACE_POKEUSR_AREA:
454 		if (copy_from_user(&parea, (void __force __user *) addr,
455 							sizeof(parea)))
456 			return -EFAULT;
457 		addr = parea.kernel_addr;
458 		data = parea.process_addr;
459 		copied = 0;
460 		while (copied < parea.len) {
461 			if (request == PTRACE_PEEKUSR_AREA)
462 				ret = peek_user(child, addr, data);
463 			else {
464 				addr_t utmp;
465 				if (get_user(utmp,
466 					     (addr_t __force __user *) data))
467 					return -EFAULT;
468 				ret = poke_user(child, addr, utmp);
469 			}
470 			if (ret)
471 				return ret;
472 			addr += sizeof(unsigned long);
473 			data += sizeof(unsigned long);
474 			copied += sizeof(unsigned long);
475 		}
476 		return 0;
477 	case PTRACE_GET_LAST_BREAK:
478 		return put_user(child->thread.last_break, (unsigned long __user *)data);
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 		return ptrace_request(child, request, addr, data);
511 	}
512 }
513 
514 #ifdef CONFIG_COMPAT
515 /*
516  * Now the fun part starts... a 31 bit program running in the
517  * 31 bit emulation tracing another program. PTRACE_PEEKTEXT,
518  * PTRACE_PEEKDATA, PTRACE_POKETEXT and PTRACE_POKEDATA are easy
519  * to handle, the difference to the 64 bit versions of the requests
520  * is that the access is done in multiples of 4 byte instead of
521  * 8 bytes (sizeof(unsigned long) on 31/64 bit).
522  * The ugly part are PTRACE_PEEKUSR, PTRACE_PEEKUSR_AREA,
523  * PTRACE_POKEUSR and PTRACE_POKEUSR_AREA. If the traced program
524  * is a 31 bit program too, the content of struct user can be
525  * emulated. A 31 bit program peeking into the struct user of
526  * a 64 bit program is a no-no.
527  */
528 
529 /*
530  * Same as peek_user_per but for a 31 bit program.
531  */
532 static inline __u32 __peek_user_per_compat(struct task_struct *child,
533 					   addr_t addr)
534 {
535 	if (addr == offsetof(struct compat_per_struct_kernel, cr9))
536 		/* Control bits of the active per set. */
537 		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
538 			PER_EVENT_IFETCH : child->thread.per_user.control;
539 	else if (addr == offsetof(struct compat_per_struct_kernel, cr10))
540 		/* Start address of the active per set. */
541 		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
542 			0 : child->thread.per_user.start;
543 	else if (addr == offsetof(struct compat_per_struct_kernel, cr11))
544 		/* End address of the active per set. */
545 		return test_thread_flag(TIF_SINGLE_STEP) ?
546 			PSW32_ADDR_INSN : child->thread.per_user.end;
547 	else if (addr == offsetof(struct compat_per_struct_kernel, bits))
548 		/* Single-step bit. */
549 		return (__u32) test_thread_flag(TIF_SINGLE_STEP) ?
550 			0x80000000 : 0;
551 	else if (addr == offsetof(struct compat_per_struct_kernel, starting_addr))
552 		/* Start address of the user specified per set. */
553 		return (__u32) child->thread.per_user.start;
554 	else if (addr == offsetof(struct compat_per_struct_kernel, ending_addr))
555 		/* End address of the user specified per set. */
556 		return (__u32) child->thread.per_user.end;
557 	else if (addr == offsetof(struct compat_per_struct_kernel, perc_atmid))
558 		/* PER code, ATMID and AI of the last PER trap */
559 		return (__u32) child->thread.per_event.cause << 16;
560 	else if (addr == offsetof(struct compat_per_struct_kernel, address))
561 		/* Address of the last PER trap */
562 		return (__u32) child->thread.per_event.address;
563 	else if (addr == offsetof(struct compat_per_struct_kernel, access_id))
564 		/* Access id of the last PER trap */
565 		return (__u32) child->thread.per_event.paid << 24;
566 	return 0;
567 }
568 
569 /*
570  * Same as peek_user but for a 31 bit program.
571  */
572 static u32 __peek_user_compat(struct task_struct *child, addr_t addr)
573 {
574 	addr_t offset;
575 	__u32 tmp;
576 
577 	if (addr < offsetof(struct compat_user, regs.acrs)) {
578 		struct pt_regs *regs = task_pt_regs(child);
579 		/*
580 		 * psw and gprs are stored on the stack
581 		 */
582 		if (addr == offsetof(struct compat_user, regs.psw.mask)) {
583 			/* Fake a 31 bit psw mask. */
584 			tmp = (__u32)(regs->psw.mask >> 32);
585 			tmp &= PSW32_MASK_USER | PSW32_MASK_RI;
586 			tmp |= PSW32_USER_BITS;
587 		} else if (addr == offsetof(struct compat_user, regs.psw.addr)) {
588 			/* Fake a 31 bit psw address. */
589 			tmp = (__u32) regs->psw.addr |
590 				(__u32)(regs->psw.mask & PSW_MASK_BA);
591 		} else {
592 			/* gpr 0-15 */
593 			tmp = *(__u32 *)((addr_t) &regs->psw + addr*2 + 4);
594 		}
595 	} else if (addr < offsetof(struct compat_user, regs.orig_gpr2)) {
596 		/*
597 		 * access registers are stored in the thread structure
598 		 */
599 		offset = addr - offsetof(struct compat_user, regs.acrs);
600 		tmp = *(__u32*)((addr_t) &child->thread.acrs + offset);
601 
602 	} else if (addr == offsetof(struct compat_user, regs.orig_gpr2)) {
603 		/*
604 		 * orig_gpr2 is stored on the kernel stack
605 		 */
606 		tmp = *(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4);
607 
608 	} else if (addr < offsetof(struct compat_user, regs.fp_regs)) {
609 		/*
610 		 * prevent reads of padding hole between
611 		 * orig_gpr2 and fp_regs on s390.
612 		 */
613 		tmp = 0;
614 
615 	} else if (addr == offsetof(struct compat_user, regs.fp_regs.fpc)) {
616 		/*
617 		 * floating point control reg. is in the thread structure
618 		 */
619 		tmp = child->thread.fpu.fpc;
620 
621 	} else if (addr < offsetof(struct compat_user, regs.fp_regs) + sizeof(s390_fp_regs)) {
622 		/*
623 		 * floating point regs. are either in child->thread.fpu
624 		 * or the child->thread.fpu.vxrs array
625 		 */
626 		offset = addr - offsetof(struct compat_user, regs.fp_regs.fprs);
627 		if (MACHINE_HAS_VX)
628 			tmp = *(__u32 *)
629 			       ((addr_t) child->thread.fpu.vxrs + 2*offset);
630 		else
631 			tmp = *(__u32 *)
632 			       ((addr_t) child->thread.fpu.fprs + offset);
633 
634 	} else if (addr < offsetof(struct compat_user, regs.per_info) + sizeof(struct compat_per_struct_kernel)) {
635 		/*
636 		 * Handle access to the per_info structure.
637 		 */
638 		addr -= offsetof(struct compat_user, regs.per_info);
639 		tmp = __peek_user_per_compat(child, addr);
640 
641 	} else
642 		tmp = 0;
643 
644 	return tmp;
645 }
646 
647 static int peek_user_compat(struct task_struct *child,
648 			    addr_t addr, addr_t data)
649 {
650 	__u32 tmp;
651 
652 	if (!is_compat_task() || (addr & 3) || addr > sizeof(struct user) - 3)
653 		return -EIO;
654 
655 	tmp = __peek_user_compat(child, addr);
656 	return put_user(tmp, (__u32 __user *) data);
657 }
658 
659 /*
660  * Same as poke_user_per but for a 31 bit program.
661  */
662 static inline void __poke_user_per_compat(struct task_struct *child,
663 					  addr_t addr, __u32 data)
664 {
665 	if (addr == offsetof(struct compat_per_struct_kernel, cr9))
666 		/* PER event mask of the user specified per set. */
667 		child->thread.per_user.control =
668 			data & (PER_EVENT_MASK | PER_CONTROL_MASK);
669 	else if (addr == offsetof(struct compat_per_struct_kernel, starting_addr))
670 		/* Starting address of the user specified per set. */
671 		child->thread.per_user.start = data;
672 	else if (addr == offsetof(struct compat_per_struct_kernel, ending_addr))
673 		/* Ending address of the user specified per set. */
674 		child->thread.per_user.end = data;
675 }
676 
677 /*
678  * Same as poke_user but for a 31 bit program.
679  */
680 static int __poke_user_compat(struct task_struct *child,
681 			      addr_t addr, addr_t data)
682 {
683 	__u32 tmp = (__u32) data;
684 	addr_t offset;
685 
686 	if (addr < offsetof(struct compat_user, regs.acrs)) {
687 		struct pt_regs *regs = task_pt_regs(child);
688 		/*
689 		 * psw, gprs, acrs and orig_gpr2 are stored on the stack
690 		 */
691 		if (addr == offsetof(struct compat_user, regs.psw.mask)) {
692 			__u32 mask = PSW32_MASK_USER;
693 
694 			mask |= is_ri_task(child) ? PSW32_MASK_RI : 0;
695 			/* Build a 64 bit psw mask from 31 bit mask. */
696 			if ((tmp ^ PSW32_USER_BITS) & ~mask)
697 				/* Invalid psw mask. */
698 				return -EINVAL;
699 			if ((data & PSW32_MASK_ASC) == PSW32_ASC_HOME)
700 				/* Invalid address-space-control bits */
701 				return -EINVAL;
702 			regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
703 				(regs->psw.mask & PSW_MASK_BA) |
704 				(__u64)(tmp & mask) << 32;
705 		} else if (addr == offsetof(struct compat_user, regs.psw.addr)) {
706 			/* Build a 64 bit psw address from 31 bit address. */
707 			regs->psw.addr = (__u64) tmp & PSW32_ADDR_INSN;
708 			/* Transfer 31 bit amode bit to psw mask. */
709 			regs->psw.mask = (regs->psw.mask & ~PSW_MASK_BA) |
710 				(__u64)(tmp & PSW32_ADDR_AMODE);
711 		} else {
712 			if (test_pt_regs_flag(regs, PIF_SYSCALL) &&
713 				addr == offsetof(struct compat_user, regs.gprs[2])) {
714 				struct pt_regs *regs = task_pt_regs(child);
715 
716 				regs->int_code = 0x20000 | (data & 0xffff);
717 			}
718 			/* gpr 0-15 */
719 			*(__u32*)((addr_t) &regs->psw + addr*2 + 4) = tmp;
720 		}
721 	} else if (addr < offsetof(struct compat_user, regs.orig_gpr2)) {
722 		/*
723 		 * access registers are stored in the thread structure
724 		 */
725 		offset = addr - offsetof(struct compat_user, regs.acrs);
726 		*(__u32*)((addr_t) &child->thread.acrs + offset) = tmp;
727 
728 	} else if (addr == offsetof(struct compat_user, regs.orig_gpr2)) {
729 		/*
730 		 * orig_gpr2 is stored on the kernel stack
731 		 */
732 		*(__u32*)((addr_t) &task_pt_regs(child)->orig_gpr2 + 4) = tmp;
733 
734 	} else if (addr < offsetof(struct compat_user, regs.fp_regs)) {
735 		/*
736 		 * prevent writess of padding hole between
737 		 * orig_gpr2 and fp_regs on s390.
738 		 */
739 		return 0;
740 
741 	} else if (addr == offsetof(struct compat_user, regs.fp_regs.fpc)) {
742 		/*
743 		 * floating point control reg. is in the thread structure
744 		 */
745 		save_fpu_regs();
746 		if (test_fp_ctl(tmp))
747 			return -EINVAL;
748 		child->thread.fpu.fpc = data;
749 
750 	} else if (addr < offsetof(struct compat_user, regs.fp_regs) + sizeof(s390_fp_regs)) {
751 		/*
752 		 * floating point regs. are either in child->thread.fpu
753 		 * or the child->thread.fpu.vxrs array
754 		 */
755 		offset = addr - offsetof(struct compat_user, regs.fp_regs.fprs);
756 		if (MACHINE_HAS_VX)
757 			*(__u32 *)((addr_t)
758 				child->thread.fpu.vxrs + 2*offset) = tmp;
759 		else
760 			*(__u32 *)((addr_t)
761 				child->thread.fpu.fprs + offset) = tmp;
762 
763 	} else if (addr < offsetof(struct compat_user, regs.per_info) + sizeof(struct compat_per_struct_kernel)) {
764 		/*
765 		 * Handle access to the per_info structure.
766 		 */
767 		addr -= offsetof(struct compat_user, regs.per_info);
768 		__poke_user_per_compat(child, addr, data);
769 	}
770 
771 	return 0;
772 }
773 
774 static int poke_user_compat(struct task_struct *child,
775 			    addr_t addr, addr_t data)
776 {
777 	if (!is_compat_task() || (addr & 3) ||
778 	    addr > sizeof(struct compat_user) - 3)
779 		return -EIO;
780 
781 	return __poke_user_compat(child, addr, data);
782 }
783 
784 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
785 			compat_ulong_t caddr, compat_ulong_t cdata)
786 {
787 	unsigned long addr = caddr;
788 	unsigned long data = cdata;
789 	compat_ptrace_area parea;
790 	int copied, ret;
791 
792 	switch (request) {
793 	case PTRACE_PEEKUSR:
794 		/* read the word at location addr in the USER area. */
795 		return peek_user_compat(child, addr, data);
796 
797 	case PTRACE_POKEUSR:
798 		/* write the word at location addr in the USER area */
799 		return poke_user_compat(child, addr, data);
800 
801 	case PTRACE_PEEKUSR_AREA:
802 	case PTRACE_POKEUSR_AREA:
803 		if (copy_from_user(&parea, (void __force __user *) addr,
804 							sizeof(parea)))
805 			return -EFAULT;
806 		addr = parea.kernel_addr;
807 		data = parea.process_addr;
808 		copied = 0;
809 		while (copied < parea.len) {
810 			if (request == PTRACE_PEEKUSR_AREA)
811 				ret = peek_user_compat(child, addr, data);
812 			else {
813 				__u32 utmp;
814 				if (get_user(utmp,
815 					     (__u32 __force __user *) data))
816 					return -EFAULT;
817 				ret = poke_user_compat(child, addr, utmp);
818 			}
819 			if (ret)
820 				return ret;
821 			addr += sizeof(unsigned int);
822 			data += sizeof(unsigned int);
823 			copied += sizeof(unsigned int);
824 		}
825 		return 0;
826 	case PTRACE_GET_LAST_BREAK:
827 		return put_user(child->thread.last_break, (unsigned int __user *)data);
828 	}
829 	return compat_ptrace_request(child, request, addr, data);
830 }
831 #endif
832 
833 /*
834  * user_regset definitions.
835  */
836 
837 static int s390_regs_get(struct task_struct *target,
838 			 const struct user_regset *regset,
839 			 struct membuf to)
840 {
841 	unsigned pos;
842 	if (target == current)
843 		save_access_regs(target->thread.acrs);
844 
845 	for (pos = 0; pos < sizeof(s390_regs); pos += sizeof(long))
846 		membuf_store(&to, __peek_user(target, pos));
847 	return 0;
848 }
849 
850 static int s390_regs_set(struct task_struct *target,
851 			 const struct user_regset *regset,
852 			 unsigned int pos, unsigned int count,
853 			 const void *kbuf, const void __user *ubuf)
854 {
855 	int rc = 0;
856 
857 	if (target == current)
858 		save_access_regs(target->thread.acrs);
859 
860 	if (kbuf) {
861 		const unsigned long *k = kbuf;
862 		while (count > 0 && !rc) {
863 			rc = __poke_user(target, pos, *k++);
864 			count -= sizeof(*k);
865 			pos += sizeof(*k);
866 		}
867 	} else {
868 		const unsigned long  __user *u = ubuf;
869 		while (count > 0 && !rc) {
870 			unsigned long word;
871 			rc = __get_user(word, u++);
872 			if (rc)
873 				break;
874 			rc = __poke_user(target, pos, word);
875 			count -= sizeof(*u);
876 			pos += sizeof(*u);
877 		}
878 	}
879 
880 	if (rc == 0 && target == current)
881 		restore_access_regs(target->thread.acrs);
882 
883 	return rc;
884 }
885 
886 static int s390_fpregs_get(struct task_struct *target,
887 			   const struct user_regset *regset,
888 			   struct membuf to)
889 {
890 	_s390_fp_regs fp_regs;
891 
892 	if (target == current)
893 		save_fpu_regs();
894 
895 	fp_regs.fpc = target->thread.fpu.fpc;
896 	fpregs_store(&fp_regs, &target->thread.fpu);
897 
898 	return membuf_write(&to, &fp_regs, sizeof(fp_regs));
899 }
900 
901 static int s390_fpregs_set(struct task_struct *target,
902 			   const struct user_regset *regset, unsigned int pos,
903 			   unsigned int count, const void *kbuf,
904 			   const void __user *ubuf)
905 {
906 	int rc = 0;
907 	freg_t fprs[__NUM_FPRS];
908 
909 	save_fpu_regs();
910 	if (MACHINE_HAS_VX)
911 		convert_vx_to_fp(fprs, target->thread.fpu.vxrs);
912 	else
913 		memcpy(&fprs, target->thread.fpu.fprs, sizeof(fprs));
914 
915 	/* If setting FPC, must validate it first. */
916 	if (count > 0 && pos < offsetof(s390_fp_regs, fprs)) {
917 		u32 ufpc[2] = { target->thread.fpu.fpc, 0 };
918 		rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ufpc,
919 					0, offsetof(s390_fp_regs, fprs));
920 		if (rc)
921 			return rc;
922 		if (ufpc[1] != 0 || test_fp_ctl(ufpc[0]))
923 			return -EINVAL;
924 		target->thread.fpu.fpc = ufpc[0];
925 	}
926 
927 	if (rc == 0 && count > 0)
928 		rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
929 					fprs, offsetof(s390_fp_regs, fprs), -1);
930 	if (rc)
931 		return rc;
932 
933 	if (MACHINE_HAS_VX)
934 		convert_fp_to_vx(target->thread.fpu.vxrs, fprs);
935 	else
936 		memcpy(target->thread.fpu.fprs, &fprs, sizeof(fprs));
937 
938 	return rc;
939 }
940 
941 static int s390_last_break_get(struct task_struct *target,
942 			       const struct user_regset *regset,
943 			       struct membuf to)
944 {
945 	return membuf_store(&to, target->thread.last_break);
946 }
947 
948 static int s390_last_break_set(struct task_struct *target,
949 			       const struct user_regset *regset,
950 			       unsigned int pos, unsigned int count,
951 			       const void *kbuf, const void __user *ubuf)
952 {
953 	return 0;
954 }
955 
956 static int s390_tdb_get(struct task_struct *target,
957 			const struct user_regset *regset,
958 			struct membuf to)
959 {
960 	struct pt_regs *regs = task_pt_regs(target);
961 	size_t size;
962 
963 	if (!(regs->int_code & 0x200))
964 		return -ENODATA;
965 	size = sizeof(target->thread.trap_tdb.data);
966 	return membuf_write(&to, target->thread.trap_tdb.data, size);
967 }
968 
969 static int s390_tdb_set(struct task_struct *target,
970 			const struct user_regset *regset,
971 			unsigned int pos, unsigned int count,
972 			const void *kbuf, const void __user *ubuf)
973 {
974 	return 0;
975 }
976 
977 static int s390_vxrs_low_get(struct task_struct *target,
978 			     const struct user_regset *regset,
979 			     struct membuf to)
980 {
981 	__u64 vxrs[__NUM_VXRS_LOW];
982 	int i;
983 
984 	if (!MACHINE_HAS_VX)
985 		return -ENODEV;
986 	if (target == current)
987 		save_fpu_regs();
988 	for (i = 0; i < __NUM_VXRS_LOW; i++)
989 		vxrs[i] = target->thread.fpu.vxrs[i].low;
990 	return membuf_write(&to, vxrs, sizeof(vxrs));
991 }
992 
993 static int s390_vxrs_low_set(struct task_struct *target,
994 			     const struct user_regset *regset,
995 			     unsigned int pos, unsigned int count,
996 			     const void *kbuf, const void __user *ubuf)
997 {
998 	__u64 vxrs[__NUM_VXRS_LOW];
999 	int i, rc;
1000 
1001 	if (!MACHINE_HAS_VX)
1002 		return -ENODEV;
1003 	if (target == current)
1004 		save_fpu_regs();
1005 
1006 	for (i = 0; i < __NUM_VXRS_LOW; i++)
1007 		vxrs[i] = target->thread.fpu.vxrs[i].low;
1008 
1009 	rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf, vxrs, 0, -1);
1010 	if (rc == 0)
1011 		for (i = 0; i < __NUM_VXRS_LOW; i++)
1012 			target->thread.fpu.vxrs[i].low = vxrs[i];
1013 
1014 	return rc;
1015 }
1016 
1017 static int s390_vxrs_high_get(struct task_struct *target,
1018 			      const struct user_regset *regset,
1019 			      struct membuf to)
1020 {
1021 	if (!MACHINE_HAS_VX)
1022 		return -ENODEV;
1023 	if (target == current)
1024 		save_fpu_regs();
1025 	return membuf_write(&to, target->thread.fpu.vxrs + __NUM_VXRS_LOW,
1026 			    __NUM_VXRS_HIGH * sizeof(__vector128));
1027 }
1028 
1029 static int s390_vxrs_high_set(struct task_struct *target,
1030 			      const struct user_regset *regset,
1031 			      unsigned int pos, unsigned int count,
1032 			      const void *kbuf, const void __user *ubuf)
1033 {
1034 	int rc;
1035 
1036 	if (!MACHINE_HAS_VX)
1037 		return -ENODEV;
1038 	if (target == current)
1039 		save_fpu_regs();
1040 
1041 	rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
1042 				target->thread.fpu.vxrs + __NUM_VXRS_LOW, 0, -1);
1043 	return rc;
1044 }
1045 
1046 static int s390_system_call_get(struct task_struct *target,
1047 				const struct user_regset *regset,
1048 				struct membuf to)
1049 {
1050 	return membuf_store(&to, target->thread.system_call);
1051 }
1052 
1053 static int s390_system_call_set(struct task_struct *target,
1054 				const struct user_regset *regset,
1055 				unsigned int pos, unsigned int count,
1056 				const void *kbuf, const void __user *ubuf)
1057 {
1058 	unsigned int *data = &target->thread.system_call;
1059 	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
1060 				  data, 0, sizeof(unsigned int));
1061 }
1062 
1063 static int s390_gs_cb_get(struct task_struct *target,
1064 			  const struct user_regset *regset,
1065 			  struct membuf to)
1066 {
1067 	struct gs_cb *data = target->thread.gs_cb;
1068 
1069 	if (!MACHINE_HAS_GS)
1070 		return -ENODEV;
1071 	if (!data)
1072 		return -ENODATA;
1073 	if (target == current)
1074 		save_gs_cb(data);
1075 	return membuf_write(&to, data, sizeof(struct gs_cb));
1076 }
1077 
1078 static int s390_gs_cb_set(struct task_struct *target,
1079 			  const struct user_regset *regset,
1080 			  unsigned int pos, unsigned int count,
1081 			  const void *kbuf, const void __user *ubuf)
1082 {
1083 	struct gs_cb gs_cb = { }, *data = NULL;
1084 	int rc;
1085 
1086 	if (!MACHINE_HAS_GS)
1087 		return -ENODEV;
1088 	if (!target->thread.gs_cb) {
1089 		data = kzalloc(sizeof(*data), GFP_KERNEL);
1090 		if (!data)
1091 			return -ENOMEM;
1092 	}
1093 	if (!target->thread.gs_cb)
1094 		gs_cb.gsd = 25;
1095 	else if (target == current)
1096 		save_gs_cb(&gs_cb);
1097 	else
1098 		gs_cb = *target->thread.gs_cb;
1099 	rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
1100 				&gs_cb, 0, sizeof(gs_cb));
1101 	if (rc) {
1102 		kfree(data);
1103 		return -EFAULT;
1104 	}
1105 	preempt_disable();
1106 	if (!target->thread.gs_cb)
1107 		target->thread.gs_cb = data;
1108 	*target->thread.gs_cb = gs_cb;
1109 	if (target == current) {
1110 		__ctl_set_bit(2, 4);
1111 		restore_gs_cb(target->thread.gs_cb);
1112 	}
1113 	preempt_enable();
1114 	return rc;
1115 }
1116 
1117 static int s390_gs_bc_get(struct task_struct *target,
1118 			  const struct user_regset *regset,
1119 			  struct membuf to)
1120 {
1121 	struct gs_cb *data = target->thread.gs_bc_cb;
1122 
1123 	if (!MACHINE_HAS_GS)
1124 		return -ENODEV;
1125 	if (!data)
1126 		return -ENODATA;
1127 	return membuf_write(&to, data, sizeof(struct gs_cb));
1128 }
1129 
1130 static int s390_gs_bc_set(struct task_struct *target,
1131 			  const struct user_regset *regset,
1132 			  unsigned int pos, unsigned int count,
1133 			  const void *kbuf, const void __user *ubuf)
1134 {
1135 	struct gs_cb *data = target->thread.gs_bc_cb;
1136 
1137 	if (!MACHINE_HAS_GS)
1138 		return -ENODEV;
1139 	if (!data) {
1140 		data = kzalloc(sizeof(*data), GFP_KERNEL);
1141 		if (!data)
1142 			return -ENOMEM;
1143 		target->thread.gs_bc_cb = data;
1144 	}
1145 	return user_regset_copyin(&pos, &count, &kbuf, &ubuf,
1146 				  data, 0, sizeof(struct gs_cb));
1147 }
1148 
1149 static bool is_ri_cb_valid(struct runtime_instr_cb *cb)
1150 {
1151 	return (cb->rca & 0x1f) == 0 &&
1152 		(cb->roa & 0xfff) == 0 &&
1153 		(cb->rla & 0xfff) == 0xfff &&
1154 		cb->s == 1 &&
1155 		cb->k == 1 &&
1156 		cb->h == 0 &&
1157 		cb->reserved1 == 0 &&
1158 		cb->ps == 1 &&
1159 		cb->qs == 0 &&
1160 		cb->pc == 1 &&
1161 		cb->qc == 0 &&
1162 		cb->reserved2 == 0 &&
1163 		cb->reserved3 == 0 &&
1164 		cb->reserved4 == 0 &&
1165 		cb->reserved5 == 0 &&
1166 		cb->reserved6 == 0 &&
1167 		cb->reserved7 == 0 &&
1168 		cb->reserved8 == 0 &&
1169 		cb->rla >= cb->roa &&
1170 		cb->rca >= cb->roa &&
1171 		cb->rca <= cb->rla+1 &&
1172 		cb->m < 3;
1173 }
1174 
1175 static int s390_runtime_instr_get(struct task_struct *target,
1176 				const struct user_regset *regset,
1177 				struct membuf to)
1178 {
1179 	struct runtime_instr_cb *data = target->thread.ri_cb;
1180 
1181 	if (!test_facility(64))
1182 		return -ENODEV;
1183 	if (!data)
1184 		return -ENODATA;
1185 
1186 	return membuf_write(&to, data, sizeof(struct runtime_instr_cb));
1187 }
1188 
1189 static int s390_runtime_instr_set(struct task_struct *target,
1190 				  const struct user_regset *regset,
1191 				  unsigned int pos, unsigned int count,
1192 				  const void *kbuf, const void __user *ubuf)
1193 {
1194 	struct runtime_instr_cb ri_cb = { }, *data = NULL;
1195 	int rc;
1196 
1197 	if (!test_facility(64))
1198 		return -ENODEV;
1199 
1200 	if (!target->thread.ri_cb) {
1201 		data = kzalloc(sizeof(*data), GFP_KERNEL);
1202 		if (!data)
1203 			return -ENOMEM;
1204 	}
1205 
1206 	if (target->thread.ri_cb) {
1207 		if (target == current)
1208 			store_runtime_instr_cb(&ri_cb);
1209 		else
1210 			ri_cb = *target->thread.ri_cb;
1211 	}
1212 
1213 	rc = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
1214 				&ri_cb, 0, sizeof(struct runtime_instr_cb));
1215 	if (rc) {
1216 		kfree(data);
1217 		return -EFAULT;
1218 	}
1219 
1220 	if (!is_ri_cb_valid(&ri_cb)) {
1221 		kfree(data);
1222 		return -EINVAL;
1223 	}
1224 	/*
1225 	 * Override access key in any case, since user space should
1226 	 * not be able to set it, nor should it care about it.
1227 	 */
1228 	ri_cb.key = PAGE_DEFAULT_KEY >> 4;
1229 	preempt_disable();
1230 	if (!target->thread.ri_cb)
1231 		target->thread.ri_cb = data;
1232 	*target->thread.ri_cb = ri_cb;
1233 	if (target == current)
1234 		load_runtime_instr_cb(target->thread.ri_cb);
1235 	preempt_enable();
1236 
1237 	return 0;
1238 }
1239 
1240 static const struct user_regset s390_regsets[] = {
1241 	{
1242 		.core_note_type = NT_PRSTATUS,
1243 		.n = sizeof(s390_regs) / sizeof(long),
1244 		.size = sizeof(long),
1245 		.align = sizeof(long),
1246 		.regset_get = s390_regs_get,
1247 		.set = s390_regs_set,
1248 	},
1249 	{
1250 		.core_note_type = NT_PRFPREG,
1251 		.n = sizeof(s390_fp_regs) / sizeof(long),
1252 		.size = sizeof(long),
1253 		.align = sizeof(long),
1254 		.regset_get = s390_fpregs_get,
1255 		.set = s390_fpregs_set,
1256 	},
1257 	{
1258 		.core_note_type = NT_S390_SYSTEM_CALL,
1259 		.n = 1,
1260 		.size = sizeof(unsigned int),
1261 		.align = sizeof(unsigned int),
1262 		.regset_get = s390_system_call_get,
1263 		.set = s390_system_call_set,
1264 	},
1265 	{
1266 		.core_note_type = NT_S390_LAST_BREAK,
1267 		.n = 1,
1268 		.size = sizeof(long),
1269 		.align = sizeof(long),
1270 		.regset_get = s390_last_break_get,
1271 		.set = s390_last_break_set,
1272 	},
1273 	{
1274 		.core_note_type = NT_S390_TDB,
1275 		.n = 1,
1276 		.size = 256,
1277 		.align = 1,
1278 		.regset_get = s390_tdb_get,
1279 		.set = s390_tdb_set,
1280 	},
1281 	{
1282 		.core_note_type = NT_S390_VXRS_LOW,
1283 		.n = __NUM_VXRS_LOW,
1284 		.size = sizeof(__u64),
1285 		.align = sizeof(__u64),
1286 		.regset_get = s390_vxrs_low_get,
1287 		.set = s390_vxrs_low_set,
1288 	},
1289 	{
1290 		.core_note_type = NT_S390_VXRS_HIGH,
1291 		.n = __NUM_VXRS_HIGH,
1292 		.size = sizeof(__vector128),
1293 		.align = sizeof(__vector128),
1294 		.regset_get = s390_vxrs_high_get,
1295 		.set = s390_vxrs_high_set,
1296 	},
1297 	{
1298 		.core_note_type = NT_S390_GS_CB,
1299 		.n = sizeof(struct gs_cb) / sizeof(__u64),
1300 		.size = sizeof(__u64),
1301 		.align = sizeof(__u64),
1302 		.regset_get = s390_gs_cb_get,
1303 		.set = s390_gs_cb_set,
1304 	},
1305 	{
1306 		.core_note_type = NT_S390_GS_BC,
1307 		.n = sizeof(struct gs_cb) / sizeof(__u64),
1308 		.size = sizeof(__u64),
1309 		.align = sizeof(__u64),
1310 		.regset_get = s390_gs_bc_get,
1311 		.set = s390_gs_bc_set,
1312 	},
1313 	{
1314 		.core_note_type = NT_S390_RI_CB,
1315 		.n = sizeof(struct runtime_instr_cb) / sizeof(__u64),
1316 		.size = sizeof(__u64),
1317 		.align = sizeof(__u64),
1318 		.regset_get = s390_runtime_instr_get,
1319 		.set = s390_runtime_instr_set,
1320 	},
1321 };
1322 
1323 static const struct user_regset_view user_s390_view = {
1324 	.name = "s390x",
1325 	.e_machine = EM_S390,
1326 	.regsets = s390_regsets,
1327 	.n = ARRAY_SIZE(s390_regsets)
1328 };
1329 
1330 #ifdef CONFIG_COMPAT
1331 static int s390_compat_regs_get(struct task_struct *target,
1332 				const struct user_regset *regset,
1333 				struct membuf to)
1334 {
1335 	unsigned n;
1336 
1337 	if (target == current)
1338 		save_access_regs(target->thread.acrs);
1339 
1340 	for (n = 0; n < sizeof(s390_compat_regs); n += sizeof(compat_ulong_t))
1341 		membuf_store(&to, __peek_user_compat(target, n));
1342 	return 0;
1343 }
1344 
1345 static int s390_compat_regs_set(struct task_struct *target,
1346 				const struct user_regset *regset,
1347 				unsigned int pos, unsigned int count,
1348 				const void *kbuf, const void __user *ubuf)
1349 {
1350 	int rc = 0;
1351 
1352 	if (target == current)
1353 		save_access_regs(target->thread.acrs);
1354 
1355 	if (kbuf) {
1356 		const compat_ulong_t *k = kbuf;
1357 		while (count > 0 && !rc) {
1358 			rc = __poke_user_compat(target, pos, *k++);
1359 			count -= sizeof(*k);
1360 			pos += sizeof(*k);
1361 		}
1362 	} else {
1363 		const compat_ulong_t  __user *u = ubuf;
1364 		while (count > 0 && !rc) {
1365 			compat_ulong_t word;
1366 			rc = __get_user(word, u++);
1367 			if (rc)
1368 				break;
1369 			rc = __poke_user_compat(target, pos, word);
1370 			count -= sizeof(*u);
1371 			pos += sizeof(*u);
1372 		}
1373 	}
1374 
1375 	if (rc == 0 && target == current)
1376 		restore_access_regs(target->thread.acrs);
1377 
1378 	return rc;
1379 }
1380 
1381 static int s390_compat_regs_high_get(struct task_struct *target,
1382 				     const struct user_regset *regset,
1383 				     struct membuf to)
1384 {
1385 	compat_ulong_t *gprs_high;
1386 	int i;
1387 
1388 	gprs_high = (compat_ulong_t *)task_pt_regs(target)->gprs;
1389 	for (i = 0; i < NUM_GPRS; i++, gprs_high += 2)
1390 		membuf_store(&to, *gprs_high);
1391 	return 0;
1392 }
1393 
1394 static int s390_compat_regs_high_set(struct task_struct *target,
1395 				     const struct user_regset *regset,
1396 				     unsigned int pos, unsigned int count,
1397 				     const void *kbuf, const void __user *ubuf)
1398 {
1399 	compat_ulong_t *gprs_high;
1400 	int rc = 0;
1401 
1402 	gprs_high = (compat_ulong_t *)
1403 		&task_pt_regs(target)->gprs[pos / sizeof(compat_ulong_t)];
1404 	if (kbuf) {
1405 		const compat_ulong_t *k = kbuf;
1406 		while (count > 0) {
1407 			*gprs_high = *k++;
1408 			*gprs_high += 2;
1409 			count -= sizeof(*k);
1410 		}
1411 	} else {
1412 		const compat_ulong_t  __user *u = ubuf;
1413 		while (count > 0 && !rc) {
1414 			unsigned long word;
1415 			rc = __get_user(word, u++);
1416 			if (rc)
1417 				break;
1418 			*gprs_high = word;
1419 			*gprs_high += 2;
1420 			count -= sizeof(*u);
1421 		}
1422 	}
1423 
1424 	return rc;
1425 }
1426 
1427 static int s390_compat_last_break_get(struct task_struct *target,
1428 				      const struct user_regset *regset,
1429 				      struct membuf to)
1430 {
1431 	compat_ulong_t last_break = target->thread.last_break;
1432 
1433 	return membuf_store(&to, (unsigned long)last_break);
1434 }
1435 
1436 static int s390_compat_last_break_set(struct task_struct *target,
1437 				      const struct user_regset *regset,
1438 				      unsigned int pos, unsigned int count,
1439 				      const void *kbuf, const void __user *ubuf)
1440 {
1441 	return 0;
1442 }
1443 
1444 static const struct user_regset s390_compat_regsets[] = {
1445 	{
1446 		.core_note_type = NT_PRSTATUS,
1447 		.n = sizeof(s390_compat_regs) / sizeof(compat_long_t),
1448 		.size = sizeof(compat_long_t),
1449 		.align = sizeof(compat_long_t),
1450 		.regset_get = s390_compat_regs_get,
1451 		.set = s390_compat_regs_set,
1452 	},
1453 	{
1454 		.core_note_type = NT_PRFPREG,
1455 		.n = sizeof(s390_fp_regs) / sizeof(compat_long_t),
1456 		.size = sizeof(compat_long_t),
1457 		.align = sizeof(compat_long_t),
1458 		.regset_get = s390_fpregs_get,
1459 		.set = s390_fpregs_set,
1460 	},
1461 	{
1462 		.core_note_type = NT_S390_SYSTEM_CALL,
1463 		.n = 1,
1464 		.size = sizeof(compat_uint_t),
1465 		.align = sizeof(compat_uint_t),
1466 		.regset_get = s390_system_call_get,
1467 		.set = s390_system_call_set,
1468 	},
1469 	{
1470 		.core_note_type = NT_S390_LAST_BREAK,
1471 		.n = 1,
1472 		.size = sizeof(long),
1473 		.align = sizeof(long),
1474 		.regset_get = s390_compat_last_break_get,
1475 		.set = s390_compat_last_break_set,
1476 	},
1477 	{
1478 		.core_note_type = NT_S390_TDB,
1479 		.n = 1,
1480 		.size = 256,
1481 		.align = 1,
1482 		.regset_get = s390_tdb_get,
1483 		.set = s390_tdb_set,
1484 	},
1485 	{
1486 		.core_note_type = NT_S390_VXRS_LOW,
1487 		.n = __NUM_VXRS_LOW,
1488 		.size = sizeof(__u64),
1489 		.align = sizeof(__u64),
1490 		.regset_get = s390_vxrs_low_get,
1491 		.set = s390_vxrs_low_set,
1492 	},
1493 	{
1494 		.core_note_type = NT_S390_VXRS_HIGH,
1495 		.n = __NUM_VXRS_HIGH,
1496 		.size = sizeof(__vector128),
1497 		.align = sizeof(__vector128),
1498 		.regset_get = s390_vxrs_high_get,
1499 		.set = s390_vxrs_high_set,
1500 	},
1501 	{
1502 		.core_note_type = NT_S390_HIGH_GPRS,
1503 		.n = sizeof(s390_compat_regs_high) / sizeof(compat_long_t),
1504 		.size = sizeof(compat_long_t),
1505 		.align = sizeof(compat_long_t),
1506 		.regset_get = s390_compat_regs_high_get,
1507 		.set = s390_compat_regs_high_set,
1508 	},
1509 	{
1510 		.core_note_type = NT_S390_GS_CB,
1511 		.n = sizeof(struct gs_cb) / sizeof(__u64),
1512 		.size = sizeof(__u64),
1513 		.align = sizeof(__u64),
1514 		.regset_get = s390_gs_cb_get,
1515 		.set = s390_gs_cb_set,
1516 	},
1517 	{
1518 		.core_note_type = NT_S390_GS_BC,
1519 		.n = sizeof(struct gs_cb) / sizeof(__u64),
1520 		.size = sizeof(__u64),
1521 		.align = sizeof(__u64),
1522 		.regset_get = s390_gs_bc_get,
1523 		.set = s390_gs_bc_set,
1524 	},
1525 	{
1526 		.core_note_type = NT_S390_RI_CB,
1527 		.n = sizeof(struct runtime_instr_cb) / sizeof(__u64),
1528 		.size = sizeof(__u64),
1529 		.align = sizeof(__u64),
1530 		.regset_get = s390_runtime_instr_get,
1531 		.set = s390_runtime_instr_set,
1532 	},
1533 };
1534 
1535 static const struct user_regset_view user_s390_compat_view = {
1536 	.name = "s390",
1537 	.e_machine = EM_S390,
1538 	.regsets = s390_compat_regsets,
1539 	.n = ARRAY_SIZE(s390_compat_regsets)
1540 };
1541 #endif
1542 
1543 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
1544 {
1545 #ifdef CONFIG_COMPAT
1546 	if (test_tsk_thread_flag(task, TIF_31BIT))
1547 		return &user_s390_compat_view;
1548 #endif
1549 	return &user_s390_view;
1550 }
1551 
1552 static const char *gpr_names[NUM_GPRS] = {
1553 	"r0", "r1",  "r2",  "r3",  "r4",  "r5",  "r6",  "r7",
1554 	"r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
1555 };
1556 
1557 unsigned long regs_get_register(struct pt_regs *regs, unsigned int offset)
1558 {
1559 	if (offset >= NUM_GPRS)
1560 		return 0;
1561 	return regs->gprs[offset];
1562 }
1563 
1564 int regs_query_register_offset(const char *name)
1565 {
1566 	unsigned long offset;
1567 
1568 	if (!name || *name != 'r')
1569 		return -EINVAL;
1570 	if (kstrtoul(name + 1, 10, &offset))
1571 		return -EINVAL;
1572 	if (offset >= NUM_GPRS)
1573 		return -EINVAL;
1574 	return offset;
1575 }
1576 
1577 const char *regs_query_register_name(unsigned int offset)
1578 {
1579 	if (offset >= NUM_GPRS)
1580 		return NULL;
1581 	return gpr_names[offset];
1582 }
1583 
1584 static int regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
1585 {
1586 	unsigned long ksp = kernel_stack_pointer(regs);
1587 
1588 	return (addr & ~(THREAD_SIZE - 1)) == (ksp & ~(THREAD_SIZE - 1));
1589 }
1590 
1591 /**
1592  * regs_get_kernel_stack_nth() - get Nth entry of the stack
1593  * @regs:pt_regs which contains kernel stack pointer.
1594  * @n:stack entry number.
1595  *
1596  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
1597  * is specifined by @regs. If the @n th entry is NOT in the kernel stack,
1598  * this returns 0.
1599  */
1600 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
1601 {
1602 	unsigned long addr;
1603 
1604 	addr = kernel_stack_pointer(regs) + n * sizeof(long);
1605 	if (!regs_within_kernel_stack(regs, addr))
1606 		return 0;
1607 	return *(unsigned long *)addr;
1608 }
1609