xref: /linux/arch/parisc/kernel/ptrace.c (revision e58e871becec2d3b04ed91c0c16fe8deac9c9dfa)
1 /*
2  * Kernel support for the ptrace() and syscall tracing interfaces.
3  *
4  * Copyright (C) 2000 Hewlett-Packard Co, Linuxcare Inc.
5  * Copyright (C) 2000 Matthew Wilcox <matthew@wil.cx>
6  * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
7  * Copyright (C) 2008-2016 Helge Deller <deller@gmx.de>
8  */
9 
10 #include <linux/kernel.h>
11 #include <linux/sched.h>
12 #include <linux/mm.h>
13 #include <linux/smp.h>
14 #include <linux/elf.h>
15 #include <linux/errno.h>
16 #include <linux/ptrace.h>
17 #include <linux/tracehook.h>
18 #include <linux/user.h>
19 #include <linux/personality.h>
20 #include <linux/regset.h>
21 #include <linux/security.h>
22 #include <linux/seccomp.h>
23 #include <linux/compat.h>
24 #include <linux/signal.h>
25 #include <linux/audit.h>
26 
27 #include <linux/uaccess.h>
28 #include <asm/pgtable.h>
29 #include <asm/processor.h>
30 #include <asm/asm-offsets.h>
31 
32 /* PSW bits we allow the debugger to modify */
33 #define USER_PSW_BITS	(PSW_N | PSW_B | PSW_V | PSW_CB)
34 
35 #define CREATE_TRACE_POINTS
36 #include <trace/events/syscalls.h>
37 
38 /*
39  * These are our native regset flavors.
40  */
41 enum parisc_regset {
42 	REGSET_GENERAL,
43 	REGSET_FP
44 };
45 
46 /*
47  * Called by kernel/ptrace.c when detaching..
48  *
49  * Make sure single step bits etc are not set.
50  */
51 void ptrace_disable(struct task_struct *task)
52 {
53 	clear_tsk_thread_flag(task, TIF_SINGLESTEP);
54 	clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
55 
56 	/* make sure the trap bits are not set */
57 	pa_psw(task)->r = 0;
58 	pa_psw(task)->t = 0;
59 	pa_psw(task)->h = 0;
60 	pa_psw(task)->l = 0;
61 }
62 
63 /*
64  * The following functions are called by ptrace_resume() when
65  * enabling or disabling single/block tracing.
66  */
67 void user_disable_single_step(struct task_struct *task)
68 {
69 	ptrace_disable(task);
70 }
71 
72 void user_enable_single_step(struct task_struct *task)
73 {
74 	clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
75 	set_tsk_thread_flag(task, TIF_SINGLESTEP);
76 
77 	if (pa_psw(task)->n) {
78 		struct siginfo si;
79 
80 		/* Nullified, just crank over the queue. */
81 		task_regs(task)->iaoq[0] = task_regs(task)->iaoq[1];
82 		task_regs(task)->iasq[0] = task_regs(task)->iasq[1];
83 		task_regs(task)->iaoq[1] = task_regs(task)->iaoq[0] + 4;
84 		pa_psw(task)->n = 0;
85 		pa_psw(task)->x = 0;
86 		pa_psw(task)->y = 0;
87 		pa_psw(task)->z = 0;
88 		pa_psw(task)->b = 0;
89 		ptrace_disable(task);
90 		/* Don't wake up the task, but let the
91 		   parent know something happened. */
92 		si.si_code = TRAP_TRACE;
93 		si.si_addr = (void __user *) (task_regs(task)->iaoq[0] & ~3);
94 		si.si_signo = SIGTRAP;
95 		si.si_errno = 0;
96 		force_sig_info(SIGTRAP, &si, task);
97 		/* notify_parent(task, SIGCHLD); */
98 		return;
99 	}
100 
101 	/* Enable recovery counter traps.  The recovery counter
102 	 * itself will be set to zero on a task switch.  If the
103 	 * task is suspended on a syscall then the syscall return
104 	 * path will overwrite the recovery counter with a suitable
105 	 * value such that it traps once back in user space.  We
106 	 * disable interrupts in the tasks PSW here also, to avoid
107 	 * interrupts while the recovery counter is decrementing.
108 	 */
109 	pa_psw(task)->r = 1;
110 	pa_psw(task)->t = 0;
111 	pa_psw(task)->h = 0;
112 	pa_psw(task)->l = 0;
113 }
114 
115 void user_enable_block_step(struct task_struct *task)
116 {
117 	clear_tsk_thread_flag(task, TIF_SINGLESTEP);
118 	set_tsk_thread_flag(task, TIF_BLOCKSTEP);
119 
120 	/* Enable taken branch trap. */
121 	pa_psw(task)->r = 0;
122 	pa_psw(task)->t = 1;
123 	pa_psw(task)->h = 0;
124 	pa_psw(task)->l = 0;
125 }
126 
127 long arch_ptrace(struct task_struct *child, long request,
128 		 unsigned long addr, unsigned long data)
129 {
130 	unsigned long __user *datap = (unsigned long __user *)data;
131 	unsigned long tmp;
132 	long ret = -EIO;
133 
134 	switch (request) {
135 
136 	/* Read the word at location addr in the USER area.  For ptraced
137 	   processes, the kernel saves all regs on a syscall. */
138 	case PTRACE_PEEKUSR:
139 		if ((addr & (sizeof(unsigned long)-1)) ||
140 		     addr >= sizeof(struct pt_regs))
141 			break;
142 		tmp = *(unsigned long *) ((char *) task_regs(child) + addr);
143 		ret = put_user(tmp, datap);
144 		break;
145 
146 	/* Write the word at location addr in the USER area.  This will need
147 	   to change when the kernel no longer saves all regs on a syscall.
148 	   FIXME.  There is a problem at the moment in that r3-r18 are only
149 	   saved if the process is ptraced on syscall entry, and even then
150 	   those values are overwritten by actual register values on syscall
151 	   exit. */
152 	case PTRACE_POKEUSR:
153 		/* Some register values written here may be ignored in
154 		 * entry.S:syscall_restore_rfi; e.g. iaoq is written with
155 		 * r31/r31+4, and not with the values in pt_regs.
156 		 */
157 		if (addr == PT_PSW) {
158 			/* Allow writing to Nullify, Divide-step-correction,
159 			 * and carry/borrow bits.
160 			 * BEWARE, if you set N, and then single step, it won't
161 			 * stop on the nullified instruction.
162 			 */
163 			data &= USER_PSW_BITS;
164 			task_regs(child)->gr[0] &= ~USER_PSW_BITS;
165 			task_regs(child)->gr[0] |= data;
166 			ret = 0;
167 			break;
168 		}
169 
170 		if ((addr & (sizeof(unsigned long)-1)) ||
171 		     addr >= sizeof(struct pt_regs))
172 			break;
173 		if ((addr >= PT_GR1 && addr <= PT_GR31) ||
174 				addr == PT_IAOQ0 || addr == PT_IAOQ1 ||
175 				(addr >= PT_FR0 && addr <= PT_FR31 + 4) ||
176 				addr == PT_SAR) {
177 			*(unsigned long *) ((char *) task_regs(child) + addr) = data;
178 			ret = 0;
179 		}
180 		break;
181 
182 	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
183 		return copy_regset_to_user(child,
184 					   task_user_regset_view(current),
185 					   REGSET_GENERAL,
186 					   0, sizeof(struct user_regs_struct),
187 					   datap);
188 
189 	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
190 		return copy_regset_from_user(child,
191 					     task_user_regset_view(current),
192 					     REGSET_GENERAL,
193 					     0, sizeof(struct user_regs_struct),
194 					     datap);
195 
196 	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
197 		return copy_regset_to_user(child,
198 					   task_user_regset_view(current),
199 					   REGSET_FP,
200 					   0, sizeof(struct user_fp_struct),
201 					   datap);
202 
203 	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
204 		return copy_regset_from_user(child,
205 					     task_user_regset_view(current),
206 					     REGSET_FP,
207 					     0, sizeof(struct user_fp_struct),
208 					     datap);
209 
210 	default:
211 		ret = ptrace_request(child, request, addr, data);
212 		break;
213 	}
214 
215 	return ret;
216 }
217 
218 
219 #ifdef CONFIG_COMPAT
220 
221 /* This function is needed to translate 32 bit pt_regs offsets in to
222  * 64 bit pt_regs offsets.  For example, a 32 bit gdb under a 64 bit kernel
223  * will request offset 12 if it wants gr3, but the lower 32 bits of
224  * the 64 bit kernels view of gr3 will be at offset 28 (3*8 + 4).
225  * This code relies on a 32 bit pt_regs being comprised of 32 bit values
226  * except for the fp registers which (a) are 64 bits, and (b) follow
227  * the gr registers at the start of pt_regs.  The 32 bit pt_regs should
228  * be half the size of the 64 bit pt_regs, plus 32*4 to allow for fr[]
229  * being 64 bit in both cases.
230  */
231 
232 static compat_ulong_t translate_usr_offset(compat_ulong_t offset)
233 {
234 	if (offset < 0)
235 		return sizeof(struct pt_regs);
236 	else if (offset <= 32*4)	/* gr[0..31] */
237 		return offset * 2 + 4;
238 	else if (offset <= 32*4+32*8)	/* gr[0..31] + fr[0..31] */
239 		return offset + 32*4;
240 	else if (offset < sizeof(struct pt_regs)/2 + 32*4)
241 		return offset * 2 + 4 - 32*8;
242 	else
243 		return sizeof(struct pt_regs);
244 }
245 
246 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
247 			compat_ulong_t addr, compat_ulong_t data)
248 {
249 	compat_uint_t tmp;
250 	long ret = -EIO;
251 
252 	switch (request) {
253 
254 	case PTRACE_PEEKUSR:
255 		if (addr & (sizeof(compat_uint_t)-1))
256 			break;
257 		addr = translate_usr_offset(addr);
258 		if (addr >= sizeof(struct pt_regs))
259 			break;
260 
261 		tmp = *(compat_uint_t *) ((char *) task_regs(child) + addr);
262 		ret = put_user(tmp, (compat_uint_t *) (unsigned long) data);
263 		break;
264 
265 	/* Write the word at location addr in the USER area.  This will need
266 	   to change when the kernel no longer saves all regs on a syscall.
267 	   FIXME.  There is a problem at the moment in that r3-r18 are only
268 	   saved if the process is ptraced on syscall entry, and even then
269 	   those values are overwritten by actual register values on syscall
270 	   exit. */
271 	case PTRACE_POKEUSR:
272 		/* Some register values written here may be ignored in
273 		 * entry.S:syscall_restore_rfi; e.g. iaoq is written with
274 		 * r31/r31+4, and not with the values in pt_regs.
275 		 */
276 		if (addr == PT_PSW) {
277 			/* Since PT_PSW==0, it is valid for 32 bit processes
278 			 * under 64 bit kernels as well.
279 			 */
280 			ret = arch_ptrace(child, request, addr, data);
281 		} else {
282 			if (addr & (sizeof(compat_uint_t)-1))
283 				break;
284 			addr = translate_usr_offset(addr);
285 			if (addr >= sizeof(struct pt_regs))
286 				break;
287 			if (addr >= PT_FR0 && addr <= PT_FR31 + 4) {
288 				/* Special case, fp regs are 64 bits anyway */
289 				*(__u64 *) ((char *) task_regs(child) + addr) = data;
290 				ret = 0;
291 			}
292 			else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) ||
293 					addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4 ||
294 					addr == PT_SAR+4) {
295 				/* Zero the top 32 bits */
296 				*(__u32 *) ((char *) task_regs(child) + addr - 4) = 0;
297 				*(__u32 *) ((char *) task_regs(child) + addr) = data;
298 				ret = 0;
299 			}
300 		}
301 		break;
302 
303 	default:
304 		ret = compat_ptrace_request(child, request, addr, data);
305 		break;
306 	}
307 
308 	return ret;
309 }
310 #endif
311 
312 long do_syscall_trace_enter(struct pt_regs *regs)
313 {
314 	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
315 	    tracehook_report_syscall_entry(regs)) {
316 		/*
317 		 * Tracing decided this syscall should not happen or the
318 		 * debugger stored an invalid system call number. Skip
319 		 * the system call and the system call restart handling.
320 		 */
321 		regs->gr[20] = -1UL;
322 		goto out;
323 	}
324 
325 	/* Do the secure computing check after ptrace. */
326 	if (secure_computing(NULL) == -1)
327 		return -1;
328 
329 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
330 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
331 		trace_sys_enter(regs, regs->gr[20]);
332 #endif
333 
334 #ifdef CONFIG_64BIT
335 	if (!is_compat_task())
336 		audit_syscall_entry(regs->gr[20], regs->gr[26], regs->gr[25],
337 				    regs->gr[24], regs->gr[23]);
338 	else
339 #endif
340 		audit_syscall_entry(regs->gr[20] & 0xffffffff,
341 			regs->gr[26] & 0xffffffff,
342 			regs->gr[25] & 0xffffffff,
343 			regs->gr[24] & 0xffffffff,
344 			regs->gr[23] & 0xffffffff);
345 
346 out:
347 	/*
348 	 * Sign extend the syscall number to 64bit since it may have been
349 	 * modified by a compat ptrace call
350 	 */
351 	return (int) ((u32) regs->gr[20]);
352 }
353 
354 void do_syscall_trace_exit(struct pt_regs *regs)
355 {
356 	int stepping = test_thread_flag(TIF_SINGLESTEP) ||
357 		test_thread_flag(TIF_BLOCKSTEP);
358 
359 	audit_syscall_exit(regs);
360 
361 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
362 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
363 		trace_sys_exit(regs, regs->gr[20]);
364 #endif
365 
366 	if (stepping || test_thread_flag(TIF_SYSCALL_TRACE))
367 		tracehook_report_syscall_exit(regs, stepping);
368 }
369 
370 
371 /*
372  * regset functions.
373  */
374 
375 static int fpr_get(struct task_struct *target,
376 		     const struct user_regset *regset,
377 		     unsigned int pos, unsigned int count,
378 		     void *kbuf, void __user *ubuf)
379 {
380 	struct pt_regs *regs = task_regs(target);
381 	__u64 *k = kbuf;
382 	__u64 __user *u = ubuf;
383 	__u64 reg;
384 
385 	pos /= sizeof(reg);
386 	count /= sizeof(reg);
387 
388 	if (kbuf)
389 		for (; count > 0 && pos < ELF_NFPREG; --count)
390 			*k++ = regs->fr[pos++];
391 	else
392 		for (; count > 0 && pos < ELF_NFPREG; --count)
393 			if (__put_user(regs->fr[pos++], u++))
394 				return -EFAULT;
395 
396 	kbuf = k;
397 	ubuf = u;
398 	pos *= sizeof(reg);
399 	count *= sizeof(reg);
400 	return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
401 					ELF_NFPREG * sizeof(reg), -1);
402 }
403 
404 static int fpr_set(struct task_struct *target,
405 		     const struct user_regset *regset,
406 		     unsigned int pos, unsigned int count,
407 		     const void *kbuf, const void __user *ubuf)
408 {
409 	struct pt_regs *regs = task_regs(target);
410 	const __u64 *k = kbuf;
411 	const __u64 __user *u = ubuf;
412 	__u64 reg;
413 
414 	pos /= sizeof(reg);
415 	count /= sizeof(reg);
416 
417 	if (kbuf)
418 		for (; count > 0 && pos < ELF_NFPREG; --count)
419 			regs->fr[pos++] = *k++;
420 	else
421 		for (; count > 0 && pos < ELF_NFPREG; --count) {
422 			if (__get_user(reg, u++))
423 				return -EFAULT;
424 			regs->fr[pos++] = reg;
425 		}
426 
427 	kbuf = k;
428 	ubuf = u;
429 	pos *= sizeof(reg);
430 	count *= sizeof(reg);
431 	return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
432 					 ELF_NFPREG * sizeof(reg), -1);
433 }
434 
435 #define RI(reg) (offsetof(struct user_regs_struct,reg) / sizeof(long))
436 
437 static unsigned long get_reg(struct pt_regs *regs, int num)
438 {
439 	switch (num) {
440 	case RI(gr[0]) ... RI(gr[31]):	return regs->gr[num - RI(gr[0])];
441 	case RI(sr[0]) ... RI(sr[7]):	return regs->sr[num - RI(sr[0])];
442 	case RI(iasq[0]):		return regs->iasq[0];
443 	case RI(iasq[1]):		return regs->iasq[1];
444 	case RI(iaoq[0]):		return regs->iaoq[0];
445 	case RI(iaoq[1]):		return regs->iaoq[1];
446 	case RI(sar):			return regs->sar;
447 	case RI(iir):			return regs->iir;
448 	case RI(isr):			return regs->isr;
449 	case RI(ior):			return regs->ior;
450 	case RI(ipsw):			return regs->ipsw;
451 	case RI(cr27):			return regs->cr27;
452 	case RI(cr0):			return mfctl(0);
453 	case RI(cr24):			return mfctl(24);
454 	case RI(cr25):			return mfctl(25);
455 	case RI(cr26):			return mfctl(26);
456 	case RI(cr28):			return mfctl(28);
457 	case RI(cr29):			return mfctl(29);
458 	case RI(cr30):			return mfctl(30);
459 	case RI(cr31):			return mfctl(31);
460 	case RI(cr8):			return mfctl(8);
461 	case RI(cr9):			return mfctl(9);
462 	case RI(cr12):			return mfctl(12);
463 	case RI(cr13):			return mfctl(13);
464 	case RI(cr10):			return mfctl(10);
465 	case RI(cr15):			return mfctl(15);
466 	default:			return 0;
467 	}
468 }
469 
470 static void set_reg(struct pt_regs *regs, int num, unsigned long val)
471 {
472 	switch (num) {
473 	case RI(gr[0]): /*
474 			 * PSW is in gr[0].
475 			 * Allow writing to Nullify, Divide-step-correction,
476 			 * and carry/borrow bits.
477 			 * BEWARE, if you set N, and then single step, it won't
478 			 * stop on the nullified instruction.
479 			 */
480 			val &= USER_PSW_BITS;
481 			regs->gr[0] &= ~USER_PSW_BITS;
482 			regs->gr[0] |= val;
483 			return;
484 	case RI(gr[1]) ... RI(gr[31]):
485 			regs->gr[num - RI(gr[0])] = val;
486 			return;
487 	case RI(iaoq[0]):
488 	case RI(iaoq[1]):
489 			regs->iaoq[num - RI(iaoq[0])] = val;
490 			return;
491 	case RI(sar):	regs->sar = val;
492 			return;
493 	default:	return;
494 #if 0
495 	/* do not allow to change any of the following registers (yet) */
496 	case RI(sr[0]) ... RI(sr[7]):	return regs->sr[num - RI(sr[0])];
497 	case RI(iasq[0]):		return regs->iasq[0];
498 	case RI(iasq[1]):		return regs->iasq[1];
499 	case RI(iir):			return regs->iir;
500 	case RI(isr):			return regs->isr;
501 	case RI(ior):			return regs->ior;
502 	case RI(ipsw):			return regs->ipsw;
503 	case RI(cr27):			return regs->cr27;
504         case cr0, cr24, cr25, cr26, cr27, cr28, cr29, cr30, cr31;
505         case cr8, cr9, cr12, cr13, cr10, cr15;
506 #endif
507 	}
508 }
509 
510 static int gpr_get(struct task_struct *target,
511 		     const struct user_regset *regset,
512 		     unsigned int pos, unsigned int count,
513 		     void *kbuf, void __user *ubuf)
514 {
515 	struct pt_regs *regs = task_regs(target);
516 	unsigned long *k = kbuf;
517 	unsigned long __user *u = ubuf;
518 	unsigned long reg;
519 
520 	pos /= sizeof(reg);
521 	count /= sizeof(reg);
522 
523 	if (kbuf)
524 		for (; count > 0 && pos < ELF_NGREG; --count)
525 			*k++ = get_reg(regs, pos++);
526 	else
527 		for (; count > 0 && pos < ELF_NGREG; --count)
528 			if (__put_user(get_reg(regs, pos++), u++))
529 				return -EFAULT;
530 	kbuf = k;
531 	ubuf = u;
532 	pos *= sizeof(reg);
533 	count *= sizeof(reg);
534 	return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
535 					ELF_NGREG * sizeof(reg), -1);
536 }
537 
538 static int gpr_set(struct task_struct *target,
539 		     const struct user_regset *regset,
540 		     unsigned int pos, unsigned int count,
541 		     const void *kbuf, const void __user *ubuf)
542 {
543 	struct pt_regs *regs = task_regs(target);
544 	const unsigned long *k = kbuf;
545 	const unsigned long __user *u = ubuf;
546 	unsigned long reg;
547 
548 	pos /= sizeof(reg);
549 	count /= sizeof(reg);
550 
551 	if (kbuf)
552 		for (; count > 0 && pos < ELF_NGREG; --count)
553 			set_reg(regs, pos++, *k++);
554 	else
555 		for (; count > 0 && pos < ELF_NGREG; --count) {
556 			if (__get_user(reg, u++))
557 				return -EFAULT;
558 			set_reg(regs, pos++, reg);
559 		}
560 
561 	kbuf = k;
562 	ubuf = u;
563 	pos *= sizeof(reg);
564 	count *= sizeof(reg);
565 	return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
566 					 ELF_NGREG * sizeof(reg), -1);
567 }
568 
569 static const struct user_regset native_regsets[] = {
570 	[REGSET_GENERAL] = {
571 		.core_note_type = NT_PRSTATUS, .n = ELF_NGREG,
572 		.size = sizeof(long), .align = sizeof(long),
573 		.get = gpr_get, .set = gpr_set
574 	},
575 	[REGSET_FP] = {
576 		.core_note_type = NT_PRFPREG, .n = ELF_NFPREG,
577 		.size = sizeof(__u64), .align = sizeof(__u64),
578 		.get = fpr_get, .set = fpr_set
579 	}
580 };
581 
582 static const struct user_regset_view user_parisc_native_view = {
583 	.name = "parisc", .e_machine = ELF_ARCH, .ei_osabi = ELFOSABI_LINUX,
584 	.regsets = native_regsets, .n = ARRAY_SIZE(native_regsets)
585 };
586 
587 #ifdef CONFIG_64BIT
588 #include <linux/compat.h>
589 
590 static int gpr32_get(struct task_struct *target,
591 		     const struct user_regset *regset,
592 		     unsigned int pos, unsigned int count,
593 		     void *kbuf, void __user *ubuf)
594 {
595 	struct pt_regs *regs = task_regs(target);
596 	compat_ulong_t *k = kbuf;
597 	compat_ulong_t __user *u = ubuf;
598 	compat_ulong_t reg;
599 
600 	pos /= sizeof(reg);
601 	count /= sizeof(reg);
602 
603 	if (kbuf)
604 		for (; count > 0 && pos < ELF_NGREG; --count)
605 			*k++ = get_reg(regs, pos++);
606 	else
607 		for (; count > 0 && pos < ELF_NGREG; --count)
608 			if (__put_user((compat_ulong_t) get_reg(regs, pos++), u++))
609 				return -EFAULT;
610 
611 	kbuf = k;
612 	ubuf = u;
613 	pos *= sizeof(reg);
614 	count *= sizeof(reg);
615 	return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
616 					ELF_NGREG * sizeof(reg), -1);
617 }
618 
619 static int gpr32_set(struct task_struct *target,
620 		     const struct user_regset *regset,
621 		     unsigned int pos, unsigned int count,
622 		     const void *kbuf, const void __user *ubuf)
623 {
624 	struct pt_regs *regs = task_regs(target);
625 	const compat_ulong_t *k = kbuf;
626 	const compat_ulong_t __user *u = ubuf;
627 	compat_ulong_t reg;
628 
629 	pos /= sizeof(reg);
630 	count /= sizeof(reg);
631 
632 	if (kbuf)
633 		for (; count > 0 && pos < ELF_NGREG; --count)
634 			set_reg(regs, pos++, *k++);
635 	else
636 		for (; count > 0 && pos < ELF_NGREG; --count) {
637 			if (__get_user(reg, u++))
638 				return -EFAULT;
639 			set_reg(regs, pos++, reg);
640 		}
641 
642 	kbuf = k;
643 	ubuf = u;
644 	pos *= sizeof(reg);
645 	count *= sizeof(reg);
646 	return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
647 					 ELF_NGREG * sizeof(reg), -1);
648 }
649 
650 /*
651  * These are the regset flavors matching the 32bit native set.
652  */
653 static const struct user_regset compat_regsets[] = {
654 	[REGSET_GENERAL] = {
655 		.core_note_type = NT_PRSTATUS, .n = ELF_NGREG,
656 		.size = sizeof(compat_long_t), .align = sizeof(compat_long_t),
657 		.get = gpr32_get, .set = gpr32_set
658 	},
659 	[REGSET_FP] = {
660 		.core_note_type = NT_PRFPREG, .n = ELF_NFPREG,
661 		.size = sizeof(__u64), .align = sizeof(__u64),
662 		.get = fpr_get, .set = fpr_set
663 	}
664 };
665 
666 static const struct user_regset_view user_parisc_compat_view = {
667 	.name = "parisc", .e_machine = EM_PARISC, .ei_osabi = ELFOSABI_LINUX,
668 	.regsets = compat_regsets, .n = ARRAY_SIZE(compat_regsets)
669 };
670 #endif	/* CONFIG_64BIT */
671 
672 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
673 {
674 	BUILD_BUG_ON(sizeof(struct user_regs_struct)/sizeof(long) != ELF_NGREG);
675 	BUILD_BUG_ON(sizeof(struct user_fp_struct)/sizeof(__u64) != ELF_NFPREG);
676 #ifdef CONFIG_64BIT
677 	if (is_compat_task())
678 		return &user_parisc_compat_view;
679 #endif
680 	return &user_parisc_native_view;
681 }
682