xref: /openbmc/linux/arch/parisc/kernel/ptrace.c (revision 2359ccdd)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Kernel support for the ptrace() and syscall tracing interfaces.
4  *
5  * Copyright (C) 2000 Hewlett-Packard Co, Linuxcare Inc.
6  * Copyright (C) 2000 Matthew Wilcox <matthew@wil.cx>
7  * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org>
8  * Copyright (C) 2008-2016 Helge Deller <deller@gmx.de>
9  */
10 
11 #include <linux/kernel.h>
12 #include <linux/sched.h>
13 #include <linux/mm.h>
14 #include <linux/smp.h>
15 #include <linux/elf.h>
16 #include <linux/errno.h>
17 #include <linux/ptrace.h>
18 #include <linux/tracehook.h>
19 #include <linux/user.h>
20 #include <linux/personality.h>
21 #include <linux/regset.h>
22 #include <linux/security.h>
23 #include <linux/seccomp.h>
24 #include <linux/compat.h>
25 #include <linux/signal.h>
26 #include <linux/audit.h>
27 
28 #include <linux/uaccess.h>
29 #include <asm/pgtable.h>
30 #include <asm/processor.h>
31 #include <asm/asm-offsets.h>
32 
33 /* PSW bits we allow the debugger to modify */
34 #define USER_PSW_BITS	(PSW_N | PSW_B | PSW_V | PSW_CB)
35 
36 #define CREATE_TRACE_POINTS
37 #include <trace/events/syscalls.h>
38 
39 /*
40  * These are our native regset flavors.
41  */
42 enum parisc_regset {
43 	REGSET_GENERAL,
44 	REGSET_FP
45 };
46 
47 /*
48  * Called by kernel/ptrace.c when detaching..
49  *
50  * Make sure single step bits etc are not set.
51  */
52 void ptrace_disable(struct task_struct *task)
53 {
54 	clear_tsk_thread_flag(task, TIF_SINGLESTEP);
55 	clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
56 
57 	/* make sure the trap bits are not set */
58 	pa_psw(task)->r = 0;
59 	pa_psw(task)->t = 0;
60 	pa_psw(task)->h = 0;
61 	pa_psw(task)->l = 0;
62 }
63 
64 /*
65  * The following functions are called by ptrace_resume() when
66  * enabling or disabling single/block tracing.
67  */
68 void user_disable_single_step(struct task_struct *task)
69 {
70 	ptrace_disable(task);
71 }
72 
73 void user_enable_single_step(struct task_struct *task)
74 {
75 	clear_tsk_thread_flag(task, TIF_BLOCKSTEP);
76 	set_tsk_thread_flag(task, TIF_SINGLESTEP);
77 
78 	if (pa_psw(task)->n) {
79 		struct siginfo si;
80 
81 		/* Nullified, just crank over the queue. */
82 		task_regs(task)->iaoq[0] = task_regs(task)->iaoq[1];
83 		task_regs(task)->iasq[0] = task_regs(task)->iasq[1];
84 		task_regs(task)->iaoq[1] = task_regs(task)->iaoq[0] + 4;
85 		pa_psw(task)->n = 0;
86 		pa_psw(task)->x = 0;
87 		pa_psw(task)->y = 0;
88 		pa_psw(task)->z = 0;
89 		pa_psw(task)->b = 0;
90 		ptrace_disable(task);
91 		/* Don't wake up the task, but let the
92 		   parent know something happened. */
93 		si.si_code = TRAP_TRACE;
94 		si.si_addr = (void __user *) (task_regs(task)->iaoq[0] & ~3);
95 		si.si_signo = SIGTRAP;
96 		si.si_errno = 0;
97 		force_sig_info(SIGTRAP, &si, task);
98 		/* notify_parent(task, SIGCHLD); */
99 		return;
100 	}
101 
102 	/* Enable recovery counter traps.  The recovery counter
103 	 * itself will be set to zero on a task switch.  If the
104 	 * task is suspended on a syscall then the syscall return
105 	 * path will overwrite the recovery counter with a suitable
106 	 * value such that it traps once back in user space.  We
107 	 * disable interrupts in the tasks PSW here also, to avoid
108 	 * interrupts while the recovery counter is decrementing.
109 	 */
110 	pa_psw(task)->r = 1;
111 	pa_psw(task)->t = 0;
112 	pa_psw(task)->h = 0;
113 	pa_psw(task)->l = 0;
114 }
115 
116 void user_enable_block_step(struct task_struct *task)
117 {
118 	clear_tsk_thread_flag(task, TIF_SINGLESTEP);
119 	set_tsk_thread_flag(task, TIF_BLOCKSTEP);
120 
121 	/* Enable taken branch trap. */
122 	pa_psw(task)->r = 0;
123 	pa_psw(task)->t = 1;
124 	pa_psw(task)->h = 0;
125 	pa_psw(task)->l = 0;
126 }
127 
128 long arch_ptrace(struct task_struct *child, long request,
129 		 unsigned long addr, unsigned long data)
130 {
131 	unsigned long __user *datap = (unsigned long __user *)data;
132 	unsigned long tmp;
133 	long ret = -EIO;
134 
135 	switch (request) {
136 
137 	/* Read the word at location addr in the USER area.  For ptraced
138 	   processes, the kernel saves all regs on a syscall. */
139 	case PTRACE_PEEKUSR:
140 		if ((addr & (sizeof(unsigned long)-1)) ||
141 		     addr >= sizeof(struct pt_regs))
142 			break;
143 		tmp = *(unsigned long *) ((char *) task_regs(child) + addr);
144 		ret = put_user(tmp, datap);
145 		break;
146 
147 	/* Write the word at location addr in the USER area.  This will need
148 	   to change when the kernel no longer saves all regs on a syscall.
149 	   FIXME.  There is a problem at the moment in that r3-r18 are only
150 	   saved if the process is ptraced on syscall entry, and even then
151 	   those values are overwritten by actual register values on syscall
152 	   exit. */
153 	case PTRACE_POKEUSR:
154 		/* Some register values written here may be ignored in
155 		 * entry.S:syscall_restore_rfi; e.g. iaoq is written with
156 		 * r31/r31+4, and not with the values in pt_regs.
157 		 */
158 		if (addr == PT_PSW) {
159 			/* Allow writing to Nullify, Divide-step-correction,
160 			 * and carry/borrow bits.
161 			 * BEWARE, if you set N, and then single step, it won't
162 			 * stop on the nullified instruction.
163 			 */
164 			data &= USER_PSW_BITS;
165 			task_regs(child)->gr[0] &= ~USER_PSW_BITS;
166 			task_regs(child)->gr[0] |= data;
167 			ret = 0;
168 			break;
169 		}
170 
171 		if ((addr & (sizeof(unsigned long)-1)) ||
172 		     addr >= sizeof(struct pt_regs))
173 			break;
174 		if ((addr >= PT_GR1 && addr <= PT_GR31) ||
175 				addr == PT_IAOQ0 || addr == PT_IAOQ1 ||
176 				(addr >= PT_FR0 && addr <= PT_FR31 + 4) ||
177 				addr == PT_SAR) {
178 			*(unsigned long *) ((char *) task_regs(child) + addr) = data;
179 			ret = 0;
180 		}
181 		break;
182 
183 	case PTRACE_GETREGS:	/* Get all gp regs from the child. */
184 		return copy_regset_to_user(child,
185 					   task_user_regset_view(current),
186 					   REGSET_GENERAL,
187 					   0, sizeof(struct user_regs_struct),
188 					   datap);
189 
190 	case PTRACE_SETREGS:	/* Set all gp regs in the child. */
191 		return copy_regset_from_user(child,
192 					     task_user_regset_view(current),
193 					     REGSET_GENERAL,
194 					     0, sizeof(struct user_regs_struct),
195 					     datap);
196 
197 	case PTRACE_GETFPREGS:	/* Get the child FPU state. */
198 		return copy_regset_to_user(child,
199 					   task_user_regset_view(current),
200 					   REGSET_FP,
201 					   0, sizeof(struct user_fp_struct),
202 					   datap);
203 
204 	case PTRACE_SETFPREGS:	/* Set the child FPU state. */
205 		return copy_regset_from_user(child,
206 					     task_user_regset_view(current),
207 					     REGSET_FP,
208 					     0, sizeof(struct user_fp_struct),
209 					     datap);
210 
211 	default:
212 		ret = ptrace_request(child, request, addr, data);
213 		break;
214 	}
215 
216 	return ret;
217 }
218 
219 
220 #ifdef CONFIG_COMPAT
221 
222 /* This function is needed to translate 32 bit pt_regs offsets in to
223  * 64 bit pt_regs offsets.  For example, a 32 bit gdb under a 64 bit kernel
224  * will request offset 12 if it wants gr3, but the lower 32 bits of
225  * the 64 bit kernels view of gr3 will be at offset 28 (3*8 + 4).
226  * This code relies on a 32 bit pt_regs being comprised of 32 bit values
227  * except for the fp registers which (a) are 64 bits, and (b) follow
228  * the gr registers at the start of pt_regs.  The 32 bit pt_regs should
229  * be half the size of the 64 bit pt_regs, plus 32*4 to allow for fr[]
230  * being 64 bit in both cases.
231  */
232 
233 static compat_ulong_t translate_usr_offset(compat_ulong_t offset)
234 {
235 	if (offset < 0)
236 		return sizeof(struct pt_regs);
237 	else if (offset <= 32*4)	/* gr[0..31] */
238 		return offset * 2 + 4;
239 	else if (offset <= 32*4+32*8)	/* gr[0..31] + fr[0..31] */
240 		return offset + 32*4;
241 	else if (offset < sizeof(struct pt_regs)/2 + 32*4)
242 		return offset * 2 + 4 - 32*8;
243 	else
244 		return sizeof(struct pt_regs);
245 }
246 
247 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
248 			compat_ulong_t addr, compat_ulong_t data)
249 {
250 	compat_uint_t tmp;
251 	long ret = -EIO;
252 
253 	switch (request) {
254 
255 	case PTRACE_PEEKUSR:
256 		if (addr & (sizeof(compat_uint_t)-1))
257 			break;
258 		addr = translate_usr_offset(addr);
259 		if (addr >= sizeof(struct pt_regs))
260 			break;
261 
262 		tmp = *(compat_uint_t *) ((char *) task_regs(child) + addr);
263 		ret = put_user(tmp, (compat_uint_t *) (unsigned long) data);
264 		break;
265 
266 	/* Write the word at location addr in the USER area.  This will need
267 	   to change when the kernel no longer saves all regs on a syscall.
268 	   FIXME.  There is a problem at the moment in that r3-r18 are only
269 	   saved if the process is ptraced on syscall entry, and even then
270 	   those values are overwritten by actual register values on syscall
271 	   exit. */
272 	case PTRACE_POKEUSR:
273 		/* Some register values written here may be ignored in
274 		 * entry.S:syscall_restore_rfi; e.g. iaoq is written with
275 		 * r31/r31+4, and not with the values in pt_regs.
276 		 */
277 		if (addr == PT_PSW) {
278 			/* Since PT_PSW==0, it is valid for 32 bit processes
279 			 * under 64 bit kernels as well.
280 			 */
281 			ret = arch_ptrace(child, request, addr, data);
282 		} else {
283 			if (addr & (sizeof(compat_uint_t)-1))
284 				break;
285 			addr = translate_usr_offset(addr);
286 			if (addr >= sizeof(struct pt_regs))
287 				break;
288 			if (addr >= PT_FR0 && addr <= PT_FR31 + 4) {
289 				/* Special case, fp regs are 64 bits anyway */
290 				*(__u64 *) ((char *) task_regs(child) + addr) = data;
291 				ret = 0;
292 			}
293 			else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) ||
294 					addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4 ||
295 					addr == PT_SAR+4) {
296 				/* Zero the top 32 bits */
297 				*(__u32 *) ((char *) task_regs(child) + addr - 4) = 0;
298 				*(__u32 *) ((char *) task_regs(child) + addr) = data;
299 				ret = 0;
300 			}
301 		}
302 		break;
303 
304 	default:
305 		ret = compat_ptrace_request(child, request, addr, data);
306 		break;
307 	}
308 
309 	return ret;
310 }
311 #endif
312 
313 long do_syscall_trace_enter(struct pt_regs *regs)
314 {
315 	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
316 	    tracehook_report_syscall_entry(regs)) {
317 		/*
318 		 * Tracing decided this syscall should not happen or the
319 		 * debugger stored an invalid system call number. Skip
320 		 * the system call and the system call restart handling.
321 		 */
322 		regs->gr[20] = -1UL;
323 		goto out;
324 	}
325 
326 	/* Do the secure computing check after ptrace. */
327 	if (secure_computing(NULL) == -1)
328 		return -1;
329 
330 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
331 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
332 		trace_sys_enter(regs, regs->gr[20]);
333 #endif
334 
335 #ifdef CONFIG_64BIT
336 	if (!is_compat_task())
337 		audit_syscall_entry(regs->gr[20], regs->gr[26], regs->gr[25],
338 				    regs->gr[24], regs->gr[23]);
339 	else
340 #endif
341 		audit_syscall_entry(regs->gr[20] & 0xffffffff,
342 			regs->gr[26] & 0xffffffff,
343 			regs->gr[25] & 0xffffffff,
344 			regs->gr[24] & 0xffffffff,
345 			regs->gr[23] & 0xffffffff);
346 
347 out:
348 	/*
349 	 * Sign extend the syscall number to 64bit since it may have been
350 	 * modified by a compat ptrace call
351 	 */
352 	return (int) ((u32) regs->gr[20]);
353 }
354 
355 void do_syscall_trace_exit(struct pt_regs *regs)
356 {
357 	int stepping = test_thread_flag(TIF_SINGLESTEP) ||
358 		test_thread_flag(TIF_BLOCKSTEP);
359 
360 	audit_syscall_exit(regs);
361 
362 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
363 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
364 		trace_sys_exit(regs, regs->gr[20]);
365 #endif
366 
367 	if (stepping || test_thread_flag(TIF_SYSCALL_TRACE))
368 		tracehook_report_syscall_exit(regs, stepping);
369 }
370 
371 
372 /*
373  * regset functions.
374  */
375 
376 static int fpr_get(struct task_struct *target,
377 		     const struct user_regset *regset,
378 		     unsigned int pos, unsigned int count,
379 		     void *kbuf, void __user *ubuf)
380 {
381 	struct pt_regs *regs = task_regs(target);
382 	__u64 *k = kbuf;
383 	__u64 __user *u = ubuf;
384 	__u64 reg;
385 
386 	pos /= sizeof(reg);
387 	count /= sizeof(reg);
388 
389 	if (kbuf)
390 		for (; count > 0 && pos < ELF_NFPREG; --count)
391 			*k++ = regs->fr[pos++];
392 	else
393 		for (; count > 0 && pos < ELF_NFPREG; --count)
394 			if (__put_user(regs->fr[pos++], u++))
395 				return -EFAULT;
396 
397 	kbuf = k;
398 	ubuf = u;
399 	pos *= sizeof(reg);
400 	count *= sizeof(reg);
401 	return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
402 					ELF_NFPREG * sizeof(reg), -1);
403 }
404 
405 static int fpr_set(struct task_struct *target,
406 		     const struct user_regset *regset,
407 		     unsigned int pos, unsigned int count,
408 		     const void *kbuf, const void __user *ubuf)
409 {
410 	struct pt_regs *regs = task_regs(target);
411 	const __u64 *k = kbuf;
412 	const __u64 __user *u = ubuf;
413 	__u64 reg;
414 
415 	pos /= sizeof(reg);
416 	count /= sizeof(reg);
417 
418 	if (kbuf)
419 		for (; count > 0 && pos < ELF_NFPREG; --count)
420 			regs->fr[pos++] = *k++;
421 	else
422 		for (; count > 0 && pos < ELF_NFPREG; --count) {
423 			if (__get_user(reg, u++))
424 				return -EFAULT;
425 			regs->fr[pos++] = reg;
426 		}
427 
428 	kbuf = k;
429 	ubuf = u;
430 	pos *= sizeof(reg);
431 	count *= sizeof(reg);
432 	return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
433 					 ELF_NFPREG * sizeof(reg), -1);
434 }
435 
436 #define RI(reg) (offsetof(struct user_regs_struct,reg) / sizeof(long))
437 
438 static unsigned long get_reg(struct pt_regs *regs, int num)
439 {
440 	switch (num) {
441 	case RI(gr[0]) ... RI(gr[31]):	return regs->gr[num - RI(gr[0])];
442 	case RI(sr[0]) ... RI(sr[7]):	return regs->sr[num - RI(sr[0])];
443 	case RI(iasq[0]):		return regs->iasq[0];
444 	case RI(iasq[1]):		return regs->iasq[1];
445 	case RI(iaoq[0]):		return regs->iaoq[0];
446 	case RI(iaoq[1]):		return regs->iaoq[1];
447 	case RI(sar):			return regs->sar;
448 	case RI(iir):			return regs->iir;
449 	case RI(isr):			return regs->isr;
450 	case RI(ior):			return regs->ior;
451 	case RI(ipsw):			return regs->ipsw;
452 	case RI(cr27):			return regs->cr27;
453 	case RI(cr0):			return mfctl(0);
454 	case RI(cr24):			return mfctl(24);
455 	case RI(cr25):			return mfctl(25);
456 	case RI(cr26):			return mfctl(26);
457 	case RI(cr28):			return mfctl(28);
458 	case RI(cr29):			return mfctl(29);
459 	case RI(cr30):			return mfctl(30);
460 	case RI(cr31):			return mfctl(31);
461 	case RI(cr8):			return mfctl(8);
462 	case RI(cr9):			return mfctl(9);
463 	case RI(cr12):			return mfctl(12);
464 	case RI(cr13):			return mfctl(13);
465 	case RI(cr10):			return mfctl(10);
466 	case RI(cr15):			return mfctl(15);
467 	default:			return 0;
468 	}
469 }
470 
471 static void set_reg(struct pt_regs *regs, int num, unsigned long val)
472 {
473 	switch (num) {
474 	case RI(gr[0]): /*
475 			 * PSW is in gr[0].
476 			 * Allow writing to Nullify, Divide-step-correction,
477 			 * and carry/borrow bits.
478 			 * BEWARE, if you set N, and then single step, it won't
479 			 * stop on the nullified instruction.
480 			 */
481 			val &= USER_PSW_BITS;
482 			regs->gr[0] &= ~USER_PSW_BITS;
483 			regs->gr[0] |= val;
484 			return;
485 	case RI(gr[1]) ... RI(gr[31]):
486 			regs->gr[num - RI(gr[0])] = val;
487 			return;
488 	case RI(iaoq[0]):
489 	case RI(iaoq[1]):
490 			regs->iaoq[num - RI(iaoq[0])] = val;
491 			return;
492 	case RI(sar):	regs->sar = val;
493 			return;
494 	default:	return;
495 #if 0
496 	/* do not allow to change any of the following registers (yet) */
497 	case RI(sr[0]) ... RI(sr[7]):	return regs->sr[num - RI(sr[0])];
498 	case RI(iasq[0]):		return regs->iasq[0];
499 	case RI(iasq[1]):		return regs->iasq[1];
500 	case RI(iir):			return regs->iir;
501 	case RI(isr):			return regs->isr;
502 	case RI(ior):			return regs->ior;
503 	case RI(ipsw):			return regs->ipsw;
504 	case RI(cr27):			return regs->cr27;
505         case cr0, cr24, cr25, cr26, cr27, cr28, cr29, cr30, cr31;
506         case cr8, cr9, cr12, cr13, cr10, cr15;
507 #endif
508 	}
509 }
510 
511 static int gpr_get(struct task_struct *target,
512 		     const struct user_regset *regset,
513 		     unsigned int pos, unsigned int count,
514 		     void *kbuf, void __user *ubuf)
515 {
516 	struct pt_regs *regs = task_regs(target);
517 	unsigned long *k = kbuf;
518 	unsigned long __user *u = ubuf;
519 	unsigned long reg;
520 
521 	pos /= sizeof(reg);
522 	count /= sizeof(reg);
523 
524 	if (kbuf)
525 		for (; count > 0 && pos < ELF_NGREG; --count)
526 			*k++ = get_reg(regs, pos++);
527 	else
528 		for (; count > 0 && pos < ELF_NGREG; --count)
529 			if (__put_user(get_reg(regs, pos++), u++))
530 				return -EFAULT;
531 	kbuf = k;
532 	ubuf = u;
533 	pos *= sizeof(reg);
534 	count *= sizeof(reg);
535 	return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
536 					ELF_NGREG * sizeof(reg), -1);
537 }
538 
539 static int gpr_set(struct task_struct *target,
540 		     const struct user_regset *regset,
541 		     unsigned int pos, unsigned int count,
542 		     const void *kbuf, const void __user *ubuf)
543 {
544 	struct pt_regs *regs = task_regs(target);
545 	const unsigned long *k = kbuf;
546 	const unsigned long __user *u = ubuf;
547 	unsigned long reg;
548 
549 	pos /= sizeof(reg);
550 	count /= sizeof(reg);
551 
552 	if (kbuf)
553 		for (; count > 0 && pos < ELF_NGREG; --count)
554 			set_reg(regs, pos++, *k++);
555 	else
556 		for (; count > 0 && pos < ELF_NGREG; --count) {
557 			if (__get_user(reg, u++))
558 				return -EFAULT;
559 			set_reg(regs, pos++, reg);
560 		}
561 
562 	kbuf = k;
563 	ubuf = u;
564 	pos *= sizeof(reg);
565 	count *= sizeof(reg);
566 	return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
567 					 ELF_NGREG * sizeof(reg), -1);
568 }
569 
570 static const struct user_regset native_regsets[] = {
571 	[REGSET_GENERAL] = {
572 		.core_note_type = NT_PRSTATUS, .n = ELF_NGREG,
573 		.size = sizeof(long), .align = sizeof(long),
574 		.get = gpr_get, .set = gpr_set
575 	},
576 	[REGSET_FP] = {
577 		.core_note_type = NT_PRFPREG, .n = ELF_NFPREG,
578 		.size = sizeof(__u64), .align = sizeof(__u64),
579 		.get = fpr_get, .set = fpr_set
580 	}
581 };
582 
583 static const struct user_regset_view user_parisc_native_view = {
584 	.name = "parisc", .e_machine = ELF_ARCH, .ei_osabi = ELFOSABI_LINUX,
585 	.regsets = native_regsets, .n = ARRAY_SIZE(native_regsets)
586 };
587 
588 #ifdef CONFIG_64BIT
589 #include <linux/compat.h>
590 
591 static int gpr32_get(struct task_struct *target,
592 		     const struct user_regset *regset,
593 		     unsigned int pos, unsigned int count,
594 		     void *kbuf, void __user *ubuf)
595 {
596 	struct pt_regs *regs = task_regs(target);
597 	compat_ulong_t *k = kbuf;
598 	compat_ulong_t __user *u = ubuf;
599 	compat_ulong_t reg;
600 
601 	pos /= sizeof(reg);
602 	count /= sizeof(reg);
603 
604 	if (kbuf)
605 		for (; count > 0 && pos < ELF_NGREG; --count)
606 			*k++ = get_reg(regs, pos++);
607 	else
608 		for (; count > 0 && pos < ELF_NGREG; --count)
609 			if (__put_user((compat_ulong_t) get_reg(regs, pos++), u++))
610 				return -EFAULT;
611 
612 	kbuf = k;
613 	ubuf = u;
614 	pos *= sizeof(reg);
615 	count *= sizeof(reg);
616 	return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
617 					ELF_NGREG * sizeof(reg), -1);
618 }
619 
620 static int gpr32_set(struct task_struct *target,
621 		     const struct user_regset *regset,
622 		     unsigned int pos, unsigned int count,
623 		     const void *kbuf, const void __user *ubuf)
624 {
625 	struct pt_regs *regs = task_regs(target);
626 	const compat_ulong_t *k = kbuf;
627 	const compat_ulong_t __user *u = ubuf;
628 	compat_ulong_t reg;
629 
630 	pos /= sizeof(reg);
631 	count /= sizeof(reg);
632 
633 	if (kbuf)
634 		for (; count > 0 && pos < ELF_NGREG; --count)
635 			set_reg(regs, pos++, *k++);
636 	else
637 		for (; count > 0 && pos < ELF_NGREG; --count) {
638 			if (__get_user(reg, u++))
639 				return -EFAULT;
640 			set_reg(regs, pos++, reg);
641 		}
642 
643 	kbuf = k;
644 	ubuf = u;
645 	pos *= sizeof(reg);
646 	count *= sizeof(reg);
647 	return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
648 					 ELF_NGREG * sizeof(reg), -1);
649 }
650 
651 /*
652  * These are the regset flavors matching the 32bit native set.
653  */
654 static const struct user_regset compat_regsets[] = {
655 	[REGSET_GENERAL] = {
656 		.core_note_type = NT_PRSTATUS, .n = ELF_NGREG,
657 		.size = sizeof(compat_long_t), .align = sizeof(compat_long_t),
658 		.get = gpr32_get, .set = gpr32_set
659 	},
660 	[REGSET_FP] = {
661 		.core_note_type = NT_PRFPREG, .n = ELF_NFPREG,
662 		.size = sizeof(__u64), .align = sizeof(__u64),
663 		.get = fpr_get, .set = fpr_set
664 	}
665 };
666 
667 static const struct user_regset_view user_parisc_compat_view = {
668 	.name = "parisc", .e_machine = EM_PARISC, .ei_osabi = ELFOSABI_LINUX,
669 	.regsets = compat_regsets, .n = ARRAY_SIZE(compat_regsets)
670 };
671 #endif	/* CONFIG_64BIT */
672 
673 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
674 {
675 	BUILD_BUG_ON(sizeof(struct user_regs_struct)/sizeof(long) != ELF_NGREG);
676 	BUILD_BUG_ON(sizeof(struct user_fp_struct)/sizeof(__u64) != ELF_NFPREG);
677 #ifdef CONFIG_64BIT
678 	if (is_compat_task())
679 		return &user_parisc_compat_view;
680 #endif
681 	return &user_parisc_native_view;
682 }
683