xref: /openbmc/linux/arch/parisc/kernel/ptrace.c (revision 37744fee)
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 		/* Nullified, just crank over the queue. */
80 		task_regs(task)->iaoq[0] = task_regs(task)->iaoq[1];
81 		task_regs(task)->iasq[0] = task_regs(task)->iasq[1];
82 		task_regs(task)->iaoq[1] = task_regs(task)->iaoq[0] + 4;
83 		pa_psw(task)->n = 0;
84 		pa_psw(task)->x = 0;
85 		pa_psw(task)->y = 0;
86 		pa_psw(task)->z = 0;
87 		pa_psw(task)->b = 0;
88 		ptrace_disable(task);
89 		/* Don't wake up the task, but let the
90 		   parent know something happened. */
91 		force_sig_fault_to_task(SIGTRAP, TRAP_TRACE,
92 					(void __user *) (task_regs(task)->iaoq[0] & ~3),
93 					task);
94 		/* notify_parent(task, SIGCHLD); */
95 		return;
96 	}
97 
98 	/* Enable recovery counter traps.  The recovery counter
99 	 * itself will be set to zero on a task switch.  If the
100 	 * task is suspended on a syscall then the syscall return
101 	 * path will overwrite the recovery counter with a suitable
102 	 * value such that it traps once back in user space.  We
103 	 * disable interrupts in the tasks PSW here also, to avoid
104 	 * interrupts while the recovery counter is decrementing.
105 	 */
106 	pa_psw(task)->r = 1;
107 	pa_psw(task)->t = 0;
108 	pa_psw(task)->h = 0;
109 	pa_psw(task)->l = 0;
110 }
111 
112 void user_enable_block_step(struct task_struct *task)
113 {
114 	clear_tsk_thread_flag(task, TIF_SINGLESTEP);
115 	set_tsk_thread_flag(task, TIF_BLOCKSTEP);
116 
117 	/* Enable taken branch trap. */
118 	pa_psw(task)->r = 0;
119 	pa_psw(task)->t = 1;
120 	pa_psw(task)->h = 0;
121 	pa_psw(task)->l = 0;
122 }
123 
124 long arch_ptrace(struct task_struct *child, long request,
125 		 unsigned long addr, unsigned long data)
126 {
127 	unsigned long __user *datap = (unsigned long __user *)data;
128 	unsigned long tmp;
129 	long ret = -EIO;
130 
131 	switch (request) {
132 
133 	/* Read the word at location addr in the USER area.  For ptraced
134 	   processes, the kernel saves all regs on a syscall. */
135 	case PTRACE_PEEKUSR:
136 		if ((addr & (sizeof(unsigned long)-1)) ||
137 		     addr >= sizeof(struct pt_regs))
138 			break;
139 		tmp = *(unsigned long *) ((char *) task_regs(child) + addr);
140 		ret = put_user(tmp, datap);
141 		break;
142 
143 	/* Write the word at location addr in the USER area.  This will need
144 	   to change when the kernel no longer saves all regs on a syscall.
145 	   FIXME.  There is a problem at the moment in that r3-r18 are only
146 	   saved if the process is ptraced on syscall entry, and even then
147 	   those values are overwritten by actual register values on syscall
148 	   exit. */
149 	case PTRACE_POKEUSR:
150 		/* Some register values written here may be ignored in
151 		 * entry.S:syscall_restore_rfi; e.g. iaoq is written with
152 		 * r31/r31+4, and not with the values in pt_regs.
153 		 */
154 		if (addr == PT_PSW) {
155 			/* Allow writing to Nullify, Divide-step-correction,
156 			 * and carry/borrow bits.
157 			 * BEWARE, if you set N, and then single step, it won't
158 			 * stop on the nullified instruction.
159 			 */
160 			data &= USER_PSW_BITS;
161 			task_regs(child)->gr[0] &= ~USER_PSW_BITS;
162 			task_regs(child)->gr[0] |= data;
163 			ret = 0;
164 			break;
165 		}
166 
167 		if ((addr & (sizeof(unsigned long)-1)) ||
168 		     addr >= sizeof(struct pt_regs))
169 			break;
170 		if (addr == PT_IAOQ0 || addr == PT_IAOQ1) {
171 			data |= 3; /* ensure userspace privilege */
172 		}
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 	compat_ulong_t pos;
235 
236 	if (offset < 32*4)	/* gr[0..31] */
237 		pos = offset * 2 + 4;
238 	else if (offset < 32*4+32*8)	/* fr[0] ... fr[31] */
239 		pos = (offset - 32*4) + PT_FR0;
240 	else if (offset < sizeof(struct pt_regs)/2 + 32*4) /* sr[0] ... ipsw */
241 		pos = (offset - 32*4 - 32*8) * 2 + PT_SR0 + 4;
242 	else
243 		pos = sizeof(struct pt_regs);
244 
245 	return pos;
246 }
247 
248 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
249 			compat_ulong_t addr, compat_ulong_t data)
250 {
251 	compat_uint_t tmp;
252 	long ret = -EIO;
253 
254 	switch (request) {
255 
256 	case PTRACE_PEEKUSR:
257 		if (addr & (sizeof(compat_uint_t)-1))
258 			break;
259 		addr = translate_usr_offset(addr);
260 		if (addr >= sizeof(struct pt_regs))
261 			break;
262 
263 		tmp = *(compat_uint_t *) ((char *) task_regs(child) + addr);
264 		ret = put_user(tmp, (compat_uint_t *) (unsigned long) data);
265 		break;
266 
267 	/* Write the word at location addr in the USER area.  This will need
268 	   to change when the kernel no longer saves all regs on a syscall.
269 	   FIXME.  There is a problem at the moment in that r3-r18 are only
270 	   saved if the process is ptraced on syscall entry, and even then
271 	   those values are overwritten by actual register values on syscall
272 	   exit. */
273 	case PTRACE_POKEUSR:
274 		/* Some register values written here may be ignored in
275 		 * entry.S:syscall_restore_rfi; e.g. iaoq is written with
276 		 * r31/r31+4, and not with the values in pt_regs.
277 		 */
278 		if (addr == PT_PSW) {
279 			/* Since PT_PSW==0, it is valid for 32 bit processes
280 			 * under 64 bit kernels as well.
281 			 */
282 			ret = arch_ptrace(child, request, addr, data);
283 		} else {
284 			if (addr & (sizeof(compat_uint_t)-1))
285 				break;
286 			addr = translate_usr_offset(addr);
287 			if (addr >= sizeof(struct pt_regs))
288 				break;
289 			if (addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4) {
290 				data |= 3; /* ensure userspace privilege */
291 			}
292 			if (addr >= PT_FR0 && addr <= PT_FR31 + 4) {
293 				/* Special case, fp regs are 64 bits anyway */
294 				*(__u32 *) ((char *) task_regs(child) + addr) = data;
295 				ret = 0;
296 			}
297 			else if ((addr >= PT_GR1+4 && addr <= PT_GR31+4) ||
298 					addr == PT_IAOQ0+4 || addr == PT_IAOQ1+4 ||
299 					addr == PT_SAR+4) {
300 				/* Zero the top 32 bits */
301 				*(__u32 *) ((char *) task_regs(child) + addr - 4) = 0;
302 				*(__u32 *) ((char *) task_regs(child) + addr) = data;
303 				ret = 0;
304 			}
305 		}
306 		break;
307 
308 	default:
309 		ret = compat_ptrace_request(child, request, addr, data);
310 		break;
311 	}
312 
313 	return ret;
314 }
315 #endif
316 
317 long do_syscall_trace_enter(struct pt_regs *regs)
318 {
319 	if (test_thread_flag(TIF_SYSCALL_TRACE)) {
320 		int rc = tracehook_report_syscall_entry(regs);
321 
322 		/*
323 		 * As tracesys_next does not set %r28 to -ENOSYS
324 		 * when %r20 is set to -1, initialize it here.
325 		 */
326 		regs->gr[28] = -ENOSYS;
327 
328 		if (rc) {
329 			/*
330 			 * A nonzero return code from
331 			 * tracehook_report_syscall_entry() tells us
332 			 * to prevent the syscall execution.  Skip
333 			 * the syscall call and the syscall restart handling.
334 			 *
335 			 * Note that the tracer may also just change
336 			 * regs->gr[20] to an invalid syscall number,
337 			 * that is handled by tracesys_next.
338 			 */
339 			regs->gr[20] = -1UL;
340 			return -1;
341 		}
342 	}
343 
344 	/* Do the secure computing check after ptrace. */
345 	if (secure_computing() == -1)
346 		return -1;
347 
348 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
349 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
350 		trace_sys_enter(regs, regs->gr[20]);
351 #endif
352 
353 #ifdef CONFIG_64BIT
354 	if (!is_compat_task())
355 		audit_syscall_entry(regs->gr[20], regs->gr[26], regs->gr[25],
356 				    regs->gr[24], regs->gr[23]);
357 	else
358 #endif
359 		audit_syscall_entry(regs->gr[20] & 0xffffffff,
360 			regs->gr[26] & 0xffffffff,
361 			regs->gr[25] & 0xffffffff,
362 			regs->gr[24] & 0xffffffff,
363 			regs->gr[23] & 0xffffffff);
364 
365 	/*
366 	 * Sign extend the syscall number to 64bit since it may have been
367 	 * modified by a compat ptrace call
368 	 */
369 	return (int) ((u32) regs->gr[20]);
370 }
371 
372 void do_syscall_trace_exit(struct pt_regs *regs)
373 {
374 	int stepping = test_thread_flag(TIF_SINGLESTEP) ||
375 		test_thread_flag(TIF_BLOCKSTEP);
376 
377 	audit_syscall_exit(regs);
378 
379 #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
380 	if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
381 		trace_sys_exit(regs, regs->gr[20]);
382 #endif
383 
384 	if (stepping || test_thread_flag(TIF_SYSCALL_TRACE))
385 		tracehook_report_syscall_exit(regs, stepping);
386 }
387 
388 
389 /*
390  * regset functions.
391  */
392 
393 static int fpr_get(struct task_struct *target,
394 		     const struct user_regset *regset,
395 		     unsigned int pos, unsigned int count,
396 		     void *kbuf, void __user *ubuf)
397 {
398 	struct pt_regs *regs = task_regs(target);
399 	__u64 *k = kbuf;
400 	__u64 __user *u = ubuf;
401 	__u64 reg;
402 
403 	pos /= sizeof(reg);
404 	count /= sizeof(reg);
405 
406 	if (kbuf)
407 		for (; count > 0 && pos < ELF_NFPREG; --count)
408 			*k++ = regs->fr[pos++];
409 	else
410 		for (; count > 0 && pos < ELF_NFPREG; --count)
411 			if (__put_user(regs->fr[pos++], u++))
412 				return -EFAULT;
413 
414 	kbuf = k;
415 	ubuf = u;
416 	pos *= sizeof(reg);
417 	count *= sizeof(reg);
418 	return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
419 					ELF_NFPREG * sizeof(reg), -1);
420 }
421 
422 static int fpr_set(struct task_struct *target,
423 		     const struct user_regset *regset,
424 		     unsigned int pos, unsigned int count,
425 		     const void *kbuf, const void __user *ubuf)
426 {
427 	struct pt_regs *regs = task_regs(target);
428 	const __u64 *k = kbuf;
429 	const __u64 __user *u = ubuf;
430 	__u64 reg;
431 
432 	pos /= sizeof(reg);
433 	count /= sizeof(reg);
434 
435 	if (kbuf)
436 		for (; count > 0 && pos < ELF_NFPREG; --count)
437 			regs->fr[pos++] = *k++;
438 	else
439 		for (; count > 0 && pos < ELF_NFPREG; --count) {
440 			if (__get_user(reg, u++))
441 				return -EFAULT;
442 			regs->fr[pos++] = reg;
443 		}
444 
445 	kbuf = k;
446 	ubuf = u;
447 	pos *= sizeof(reg);
448 	count *= sizeof(reg);
449 	return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
450 					 ELF_NFPREG * sizeof(reg), -1);
451 }
452 
453 #define RI(reg) (offsetof(struct user_regs_struct,reg) / sizeof(long))
454 
455 static unsigned long get_reg(struct pt_regs *regs, int num)
456 {
457 	switch (num) {
458 	case RI(gr[0]) ... RI(gr[31]):	return regs->gr[num - RI(gr[0])];
459 	case RI(sr[0]) ... RI(sr[7]):	return regs->sr[num - RI(sr[0])];
460 	case RI(iasq[0]):		return regs->iasq[0];
461 	case RI(iasq[1]):		return regs->iasq[1];
462 	case RI(iaoq[0]):		return regs->iaoq[0];
463 	case RI(iaoq[1]):		return regs->iaoq[1];
464 	case RI(sar):			return regs->sar;
465 	case RI(iir):			return regs->iir;
466 	case RI(isr):			return regs->isr;
467 	case RI(ior):			return regs->ior;
468 	case RI(ipsw):			return regs->ipsw;
469 	case RI(cr27):			return regs->cr27;
470 	case RI(cr0):			return mfctl(0);
471 	case RI(cr24):			return mfctl(24);
472 	case RI(cr25):			return mfctl(25);
473 	case RI(cr26):			return mfctl(26);
474 	case RI(cr28):			return mfctl(28);
475 	case RI(cr29):			return mfctl(29);
476 	case RI(cr30):			return mfctl(30);
477 	case RI(cr31):			return mfctl(31);
478 	case RI(cr8):			return mfctl(8);
479 	case RI(cr9):			return mfctl(9);
480 	case RI(cr12):			return mfctl(12);
481 	case RI(cr13):			return mfctl(13);
482 	case RI(cr10):			return mfctl(10);
483 	case RI(cr15):			return mfctl(15);
484 	default:			return 0;
485 	}
486 }
487 
488 static void set_reg(struct pt_regs *regs, int num, unsigned long val)
489 {
490 	switch (num) {
491 	case RI(gr[0]): /*
492 			 * PSW is in gr[0].
493 			 * Allow writing to Nullify, Divide-step-correction,
494 			 * and carry/borrow bits.
495 			 * BEWARE, if you set N, and then single step, it won't
496 			 * stop on the nullified instruction.
497 			 */
498 			val &= USER_PSW_BITS;
499 			regs->gr[0] &= ~USER_PSW_BITS;
500 			regs->gr[0] |= val;
501 			return;
502 	case RI(gr[1]) ... RI(gr[31]):
503 			regs->gr[num - RI(gr[0])] = val;
504 			return;
505 	case RI(iaoq[0]):
506 	case RI(iaoq[1]):
507 			/* set 2 lowest bits to ensure userspace privilege: */
508 			regs->iaoq[num - RI(iaoq[0])] = val | 3;
509 			return;
510 	case RI(sar):	regs->sar = val;
511 			return;
512 	default:	return;
513 #if 0
514 	/* do not allow to change any of the following registers (yet) */
515 	case RI(sr[0]) ... RI(sr[7]):	return regs->sr[num - RI(sr[0])];
516 	case RI(iasq[0]):		return regs->iasq[0];
517 	case RI(iasq[1]):		return regs->iasq[1];
518 	case RI(iir):			return regs->iir;
519 	case RI(isr):			return regs->isr;
520 	case RI(ior):			return regs->ior;
521 	case RI(ipsw):			return regs->ipsw;
522 	case RI(cr27):			return regs->cr27;
523         case cr0, cr24, cr25, cr26, cr27, cr28, cr29, cr30, cr31;
524         case cr8, cr9, cr12, cr13, cr10, cr15;
525 #endif
526 	}
527 }
528 
529 static int gpr_get(struct task_struct *target,
530 		     const struct user_regset *regset,
531 		     unsigned int pos, unsigned int count,
532 		     void *kbuf, void __user *ubuf)
533 {
534 	struct pt_regs *regs = task_regs(target);
535 	unsigned long *k = kbuf;
536 	unsigned long __user *u = ubuf;
537 	unsigned long reg;
538 
539 	pos /= sizeof(reg);
540 	count /= sizeof(reg);
541 
542 	if (kbuf)
543 		for (; count > 0 && pos < ELF_NGREG; --count)
544 			*k++ = get_reg(regs, pos++);
545 	else
546 		for (; count > 0 && pos < ELF_NGREG; --count)
547 			if (__put_user(get_reg(regs, pos++), u++))
548 				return -EFAULT;
549 	kbuf = k;
550 	ubuf = u;
551 	pos *= sizeof(reg);
552 	count *= sizeof(reg);
553 	return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
554 					ELF_NGREG * sizeof(reg), -1);
555 }
556 
557 static int gpr_set(struct task_struct *target,
558 		     const struct user_regset *regset,
559 		     unsigned int pos, unsigned int count,
560 		     const void *kbuf, const void __user *ubuf)
561 {
562 	struct pt_regs *regs = task_regs(target);
563 	const unsigned long *k = kbuf;
564 	const unsigned long __user *u = ubuf;
565 	unsigned long reg;
566 
567 	pos /= sizeof(reg);
568 	count /= sizeof(reg);
569 
570 	if (kbuf)
571 		for (; count > 0 && pos < ELF_NGREG; --count)
572 			set_reg(regs, pos++, *k++);
573 	else
574 		for (; count > 0 && pos < ELF_NGREG; --count) {
575 			if (__get_user(reg, u++))
576 				return -EFAULT;
577 			set_reg(regs, pos++, reg);
578 		}
579 
580 	kbuf = k;
581 	ubuf = u;
582 	pos *= sizeof(reg);
583 	count *= sizeof(reg);
584 	return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
585 					 ELF_NGREG * sizeof(reg), -1);
586 }
587 
588 static const struct user_regset native_regsets[] = {
589 	[REGSET_GENERAL] = {
590 		.core_note_type = NT_PRSTATUS, .n = ELF_NGREG,
591 		.size = sizeof(long), .align = sizeof(long),
592 		.get = gpr_get, .set = gpr_set
593 	},
594 	[REGSET_FP] = {
595 		.core_note_type = NT_PRFPREG, .n = ELF_NFPREG,
596 		.size = sizeof(__u64), .align = sizeof(__u64),
597 		.get = fpr_get, .set = fpr_set
598 	}
599 };
600 
601 static const struct user_regset_view user_parisc_native_view = {
602 	.name = "parisc", .e_machine = ELF_ARCH, .ei_osabi = ELFOSABI_LINUX,
603 	.regsets = native_regsets, .n = ARRAY_SIZE(native_regsets)
604 };
605 
606 #ifdef CONFIG_64BIT
607 #include <linux/compat.h>
608 
609 static int gpr32_get(struct task_struct *target,
610 		     const struct user_regset *regset,
611 		     unsigned int pos, unsigned int count,
612 		     void *kbuf, void __user *ubuf)
613 {
614 	struct pt_regs *regs = task_regs(target);
615 	compat_ulong_t *k = kbuf;
616 	compat_ulong_t __user *u = ubuf;
617 	compat_ulong_t reg;
618 
619 	pos /= sizeof(reg);
620 	count /= sizeof(reg);
621 
622 	if (kbuf)
623 		for (; count > 0 && pos < ELF_NGREG; --count)
624 			*k++ = get_reg(regs, pos++);
625 	else
626 		for (; count > 0 && pos < ELF_NGREG; --count)
627 			if (__put_user((compat_ulong_t) get_reg(regs, pos++), u++))
628 				return -EFAULT;
629 
630 	kbuf = k;
631 	ubuf = u;
632 	pos *= sizeof(reg);
633 	count *= sizeof(reg);
634 	return user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
635 					ELF_NGREG * sizeof(reg), -1);
636 }
637 
638 static int gpr32_set(struct task_struct *target,
639 		     const struct user_regset *regset,
640 		     unsigned int pos, unsigned int count,
641 		     const void *kbuf, const void __user *ubuf)
642 {
643 	struct pt_regs *regs = task_regs(target);
644 	const compat_ulong_t *k = kbuf;
645 	const compat_ulong_t __user *u = ubuf;
646 	compat_ulong_t reg;
647 
648 	pos /= sizeof(reg);
649 	count /= sizeof(reg);
650 
651 	if (kbuf)
652 		for (; count > 0 && pos < ELF_NGREG; --count)
653 			set_reg(regs, pos++, *k++);
654 	else
655 		for (; count > 0 && pos < ELF_NGREG; --count) {
656 			if (__get_user(reg, u++))
657 				return -EFAULT;
658 			set_reg(regs, pos++, reg);
659 		}
660 
661 	kbuf = k;
662 	ubuf = u;
663 	pos *= sizeof(reg);
664 	count *= sizeof(reg);
665 	return user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
666 					 ELF_NGREG * sizeof(reg), -1);
667 }
668 
669 /*
670  * These are the regset flavors matching the 32bit native set.
671  */
672 static const struct user_regset compat_regsets[] = {
673 	[REGSET_GENERAL] = {
674 		.core_note_type = NT_PRSTATUS, .n = ELF_NGREG,
675 		.size = sizeof(compat_long_t), .align = sizeof(compat_long_t),
676 		.get = gpr32_get, .set = gpr32_set
677 	},
678 	[REGSET_FP] = {
679 		.core_note_type = NT_PRFPREG, .n = ELF_NFPREG,
680 		.size = sizeof(__u64), .align = sizeof(__u64),
681 		.get = fpr_get, .set = fpr_set
682 	}
683 };
684 
685 static const struct user_regset_view user_parisc_compat_view = {
686 	.name = "parisc", .e_machine = EM_PARISC, .ei_osabi = ELFOSABI_LINUX,
687 	.regsets = compat_regsets, .n = ARRAY_SIZE(compat_regsets)
688 };
689 #endif	/* CONFIG_64BIT */
690 
691 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
692 {
693 	BUILD_BUG_ON(sizeof(struct user_regs_struct)/sizeof(long) != ELF_NGREG);
694 	BUILD_BUG_ON(sizeof(struct user_fp_struct)/sizeof(__u64) != ELF_NFPREG);
695 #ifdef CONFIG_64BIT
696 	if (is_compat_task())
697 		return &user_parisc_compat_view;
698 #endif
699 	return &user_parisc_native_view;
700 }
701 
702 
703 /* HAVE_REGS_AND_STACK_ACCESS_API feature */
704 
705 struct pt_regs_offset {
706 	const char *name;
707 	int offset;
708 };
709 
710 #define REG_OFFSET_NAME(r)    {.name = #r, .offset = offsetof(struct pt_regs, r)}
711 #define REG_OFFSET_INDEX(r,i) {.name = #r#i, .offset = offsetof(struct pt_regs, r[i])}
712 #define REG_OFFSET_END {.name = NULL, .offset = 0}
713 
714 static const struct pt_regs_offset regoffset_table[] = {
715 	REG_OFFSET_INDEX(gr,0),
716 	REG_OFFSET_INDEX(gr,1),
717 	REG_OFFSET_INDEX(gr,2),
718 	REG_OFFSET_INDEX(gr,3),
719 	REG_OFFSET_INDEX(gr,4),
720 	REG_OFFSET_INDEX(gr,5),
721 	REG_OFFSET_INDEX(gr,6),
722 	REG_OFFSET_INDEX(gr,7),
723 	REG_OFFSET_INDEX(gr,8),
724 	REG_OFFSET_INDEX(gr,9),
725 	REG_OFFSET_INDEX(gr,10),
726 	REG_OFFSET_INDEX(gr,11),
727 	REG_OFFSET_INDEX(gr,12),
728 	REG_OFFSET_INDEX(gr,13),
729 	REG_OFFSET_INDEX(gr,14),
730 	REG_OFFSET_INDEX(gr,15),
731 	REG_OFFSET_INDEX(gr,16),
732 	REG_OFFSET_INDEX(gr,17),
733 	REG_OFFSET_INDEX(gr,18),
734 	REG_OFFSET_INDEX(gr,19),
735 	REG_OFFSET_INDEX(gr,20),
736 	REG_OFFSET_INDEX(gr,21),
737 	REG_OFFSET_INDEX(gr,22),
738 	REG_OFFSET_INDEX(gr,23),
739 	REG_OFFSET_INDEX(gr,24),
740 	REG_OFFSET_INDEX(gr,25),
741 	REG_OFFSET_INDEX(gr,26),
742 	REG_OFFSET_INDEX(gr,27),
743 	REG_OFFSET_INDEX(gr,28),
744 	REG_OFFSET_INDEX(gr,29),
745 	REG_OFFSET_INDEX(gr,30),
746 	REG_OFFSET_INDEX(gr,31),
747 	REG_OFFSET_INDEX(sr,0),
748 	REG_OFFSET_INDEX(sr,1),
749 	REG_OFFSET_INDEX(sr,2),
750 	REG_OFFSET_INDEX(sr,3),
751 	REG_OFFSET_INDEX(sr,4),
752 	REG_OFFSET_INDEX(sr,5),
753 	REG_OFFSET_INDEX(sr,6),
754 	REG_OFFSET_INDEX(sr,7),
755 	REG_OFFSET_INDEX(iasq,0),
756 	REG_OFFSET_INDEX(iasq,1),
757 	REG_OFFSET_INDEX(iaoq,0),
758 	REG_OFFSET_INDEX(iaoq,1),
759 	REG_OFFSET_NAME(cr27),
760 	REG_OFFSET_NAME(ksp),
761 	REG_OFFSET_NAME(kpc),
762 	REG_OFFSET_NAME(sar),
763 	REG_OFFSET_NAME(iir),
764 	REG_OFFSET_NAME(isr),
765 	REG_OFFSET_NAME(ior),
766 	REG_OFFSET_NAME(ipsw),
767 	REG_OFFSET_END,
768 };
769 
770 /**
771  * regs_query_register_offset() - query register offset from its name
772  * @name:	the name of a register
773  *
774  * regs_query_register_offset() returns the offset of a register in struct
775  * pt_regs from its name. If the name is invalid, this returns -EINVAL;
776  */
777 int regs_query_register_offset(const char *name)
778 {
779 	const struct pt_regs_offset *roff;
780 	for (roff = regoffset_table; roff->name != NULL; roff++)
781 		if (!strcmp(roff->name, name))
782 			return roff->offset;
783 	return -EINVAL;
784 }
785 
786 /**
787  * regs_query_register_name() - query register name from its offset
788  * @offset:	the offset of a register in struct pt_regs.
789  *
790  * regs_query_register_name() returns the name of a register from its
791  * offset in struct pt_regs. If the @offset is invalid, this returns NULL;
792  */
793 const char *regs_query_register_name(unsigned int offset)
794 {
795 	const struct pt_regs_offset *roff;
796 	for (roff = regoffset_table; roff->name != NULL; roff++)
797 		if (roff->offset == offset)
798 			return roff->name;
799 	return NULL;
800 }
801 
802 /**
803  * regs_within_kernel_stack() - check the address in the stack
804  * @regs:      pt_regs which contains kernel stack pointer.
805  * @addr:      address which is checked.
806  *
807  * regs_within_kernel_stack() checks @addr is within the kernel stack page(s).
808  * If @addr is within the kernel stack, it returns true. If not, returns false.
809  */
810 int regs_within_kernel_stack(struct pt_regs *regs, unsigned long addr)
811 {
812 	return ((addr & ~(THREAD_SIZE - 1))  ==
813 		(kernel_stack_pointer(regs) & ~(THREAD_SIZE - 1)));
814 }
815 
816 /**
817  * regs_get_kernel_stack_nth() - get Nth entry of the stack
818  * @regs:	pt_regs which contains kernel stack pointer.
819  * @n:		stack entry number.
820  *
821  * regs_get_kernel_stack_nth() returns @n th entry of the kernel stack which
822  * is specified by @regs. If the @n th entry is NOT in the kernel stack,
823  * this returns 0.
824  */
825 unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n)
826 {
827 	unsigned long *addr = (unsigned long *)kernel_stack_pointer(regs);
828 
829 	addr -= n;
830 
831 	if (!regs_within_kernel_stack(regs, (unsigned long)addr))
832 		return 0;
833 
834 	return *addr;
835 }
836