xref: /openbmc/linux/arch/arm64/kernel/ptrace.c (revision 6774def6)
1 /*
2  * Based on arch/arm/kernel/ptrace.c
3  *
4  * By Ross Biro 1/23/92
5  * edited by Linus Torvalds
6  * ARM modifications Copyright (C) 2000 Russell King
7  * Copyright (C) 2012 ARM Ltd.
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
20  */
21 
22 #include <linux/audit.h>
23 #include <linux/compat.h>
24 #include <linux/kernel.h>
25 #include <linux/sched.h>
26 #include <linux/mm.h>
27 #include <linux/smp.h>
28 #include <linux/ptrace.h>
29 #include <linux/user.h>
30 #include <linux/security.h>
31 #include <linux/init.h>
32 #include <linux/signal.h>
33 #include <linux/uaccess.h>
34 #include <linux/perf_event.h>
35 #include <linux/hw_breakpoint.h>
36 #include <linux/regset.h>
37 #include <linux/tracehook.h>
38 #include <linux/elf.h>
39 
40 #include <asm/compat.h>
41 #include <asm/debug-monitors.h>
42 #include <asm/pgtable.h>
43 #include <asm/syscall.h>
44 #include <asm/traps.h>
45 #include <asm/system_misc.h>
46 
47 #define CREATE_TRACE_POINTS
48 #include <trace/events/syscalls.h>
49 
50 /*
51  * TODO: does not yet catch signals sent when the child dies.
52  * in exit.c or in signal.c.
53  */
54 
55 /*
56  * Called by kernel/ptrace.c when detaching..
57  */
58 void ptrace_disable(struct task_struct *child)
59 {
60 }
61 
62 #ifdef CONFIG_HAVE_HW_BREAKPOINT
63 /*
64  * Handle hitting a HW-breakpoint.
65  */
66 static void ptrace_hbptriggered(struct perf_event *bp,
67 				struct perf_sample_data *data,
68 				struct pt_regs *regs)
69 {
70 	struct arch_hw_breakpoint *bkpt = counter_arch_bp(bp);
71 	siginfo_t info = {
72 		.si_signo	= SIGTRAP,
73 		.si_errno	= 0,
74 		.si_code	= TRAP_HWBKPT,
75 		.si_addr	= (void __user *)(bkpt->trigger),
76 	};
77 
78 #ifdef CONFIG_COMPAT
79 	int i;
80 
81 	if (!is_compat_task())
82 		goto send_sig;
83 
84 	for (i = 0; i < ARM_MAX_BRP; ++i) {
85 		if (current->thread.debug.hbp_break[i] == bp) {
86 			info.si_errno = (i << 1) + 1;
87 			break;
88 		}
89 	}
90 
91 	for (i = 0; i < ARM_MAX_WRP; ++i) {
92 		if (current->thread.debug.hbp_watch[i] == bp) {
93 			info.si_errno = -((i << 1) + 1);
94 			break;
95 		}
96 	}
97 
98 send_sig:
99 #endif
100 	force_sig_info(SIGTRAP, &info, current);
101 }
102 
103 /*
104  * Unregister breakpoints from this task and reset the pointers in
105  * the thread_struct.
106  */
107 void flush_ptrace_hw_breakpoint(struct task_struct *tsk)
108 {
109 	int i;
110 	struct thread_struct *t = &tsk->thread;
111 
112 	for (i = 0; i < ARM_MAX_BRP; i++) {
113 		if (t->debug.hbp_break[i]) {
114 			unregister_hw_breakpoint(t->debug.hbp_break[i]);
115 			t->debug.hbp_break[i] = NULL;
116 		}
117 	}
118 
119 	for (i = 0; i < ARM_MAX_WRP; i++) {
120 		if (t->debug.hbp_watch[i]) {
121 			unregister_hw_breakpoint(t->debug.hbp_watch[i]);
122 			t->debug.hbp_watch[i] = NULL;
123 		}
124 	}
125 }
126 
127 void ptrace_hw_copy_thread(struct task_struct *tsk)
128 {
129 	memset(&tsk->thread.debug, 0, sizeof(struct debug_info));
130 }
131 
132 static struct perf_event *ptrace_hbp_get_event(unsigned int note_type,
133 					       struct task_struct *tsk,
134 					       unsigned long idx)
135 {
136 	struct perf_event *bp = ERR_PTR(-EINVAL);
137 
138 	switch (note_type) {
139 	case NT_ARM_HW_BREAK:
140 		if (idx < ARM_MAX_BRP)
141 			bp = tsk->thread.debug.hbp_break[idx];
142 		break;
143 	case NT_ARM_HW_WATCH:
144 		if (idx < ARM_MAX_WRP)
145 			bp = tsk->thread.debug.hbp_watch[idx];
146 		break;
147 	}
148 
149 	return bp;
150 }
151 
152 static int ptrace_hbp_set_event(unsigned int note_type,
153 				struct task_struct *tsk,
154 				unsigned long idx,
155 				struct perf_event *bp)
156 {
157 	int err = -EINVAL;
158 
159 	switch (note_type) {
160 	case NT_ARM_HW_BREAK:
161 		if (idx < ARM_MAX_BRP) {
162 			tsk->thread.debug.hbp_break[idx] = bp;
163 			err = 0;
164 		}
165 		break;
166 	case NT_ARM_HW_WATCH:
167 		if (idx < ARM_MAX_WRP) {
168 			tsk->thread.debug.hbp_watch[idx] = bp;
169 			err = 0;
170 		}
171 		break;
172 	}
173 
174 	return err;
175 }
176 
177 static struct perf_event *ptrace_hbp_create(unsigned int note_type,
178 					    struct task_struct *tsk,
179 					    unsigned long idx)
180 {
181 	struct perf_event *bp;
182 	struct perf_event_attr attr;
183 	int err, type;
184 
185 	switch (note_type) {
186 	case NT_ARM_HW_BREAK:
187 		type = HW_BREAKPOINT_X;
188 		break;
189 	case NT_ARM_HW_WATCH:
190 		type = HW_BREAKPOINT_RW;
191 		break;
192 	default:
193 		return ERR_PTR(-EINVAL);
194 	}
195 
196 	ptrace_breakpoint_init(&attr);
197 
198 	/*
199 	 * Initialise fields to sane defaults
200 	 * (i.e. values that will pass validation).
201 	 */
202 	attr.bp_addr	= 0;
203 	attr.bp_len	= HW_BREAKPOINT_LEN_4;
204 	attr.bp_type	= type;
205 	attr.disabled	= 1;
206 
207 	bp = register_user_hw_breakpoint(&attr, ptrace_hbptriggered, NULL, tsk);
208 	if (IS_ERR(bp))
209 		return bp;
210 
211 	err = ptrace_hbp_set_event(note_type, tsk, idx, bp);
212 	if (err)
213 		return ERR_PTR(err);
214 
215 	return bp;
216 }
217 
218 static int ptrace_hbp_fill_attr_ctrl(unsigned int note_type,
219 				     struct arch_hw_breakpoint_ctrl ctrl,
220 				     struct perf_event_attr *attr)
221 {
222 	int err, len, type, disabled = !ctrl.enabled;
223 
224 	attr->disabled = disabled;
225 	if (disabled)
226 		return 0;
227 
228 	err = arch_bp_generic_fields(ctrl, &len, &type);
229 	if (err)
230 		return err;
231 
232 	switch (note_type) {
233 	case NT_ARM_HW_BREAK:
234 		if ((type & HW_BREAKPOINT_X) != type)
235 			return -EINVAL;
236 		break;
237 	case NT_ARM_HW_WATCH:
238 		if ((type & HW_BREAKPOINT_RW) != type)
239 			return -EINVAL;
240 		break;
241 	default:
242 		return -EINVAL;
243 	}
244 
245 	attr->bp_len	= len;
246 	attr->bp_type	= type;
247 
248 	return 0;
249 }
250 
251 static int ptrace_hbp_get_resource_info(unsigned int note_type, u32 *info)
252 {
253 	u8 num;
254 	u32 reg = 0;
255 
256 	switch (note_type) {
257 	case NT_ARM_HW_BREAK:
258 		num = hw_breakpoint_slots(TYPE_INST);
259 		break;
260 	case NT_ARM_HW_WATCH:
261 		num = hw_breakpoint_slots(TYPE_DATA);
262 		break;
263 	default:
264 		return -EINVAL;
265 	}
266 
267 	reg |= debug_monitors_arch();
268 	reg <<= 8;
269 	reg |= num;
270 
271 	*info = reg;
272 	return 0;
273 }
274 
275 static int ptrace_hbp_get_ctrl(unsigned int note_type,
276 			       struct task_struct *tsk,
277 			       unsigned long idx,
278 			       u32 *ctrl)
279 {
280 	struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
281 
282 	if (IS_ERR(bp))
283 		return PTR_ERR(bp);
284 
285 	*ctrl = bp ? encode_ctrl_reg(counter_arch_bp(bp)->ctrl) : 0;
286 	return 0;
287 }
288 
289 static int ptrace_hbp_get_addr(unsigned int note_type,
290 			       struct task_struct *tsk,
291 			       unsigned long idx,
292 			       u64 *addr)
293 {
294 	struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
295 
296 	if (IS_ERR(bp))
297 		return PTR_ERR(bp);
298 
299 	*addr = bp ? bp->attr.bp_addr : 0;
300 	return 0;
301 }
302 
303 static struct perf_event *ptrace_hbp_get_initialised_bp(unsigned int note_type,
304 							struct task_struct *tsk,
305 							unsigned long idx)
306 {
307 	struct perf_event *bp = ptrace_hbp_get_event(note_type, tsk, idx);
308 
309 	if (!bp)
310 		bp = ptrace_hbp_create(note_type, tsk, idx);
311 
312 	return bp;
313 }
314 
315 static int ptrace_hbp_set_ctrl(unsigned int note_type,
316 			       struct task_struct *tsk,
317 			       unsigned long idx,
318 			       u32 uctrl)
319 {
320 	int err;
321 	struct perf_event *bp;
322 	struct perf_event_attr attr;
323 	struct arch_hw_breakpoint_ctrl ctrl;
324 
325 	bp = ptrace_hbp_get_initialised_bp(note_type, tsk, idx);
326 	if (IS_ERR(bp)) {
327 		err = PTR_ERR(bp);
328 		return err;
329 	}
330 
331 	attr = bp->attr;
332 	decode_ctrl_reg(uctrl, &ctrl);
333 	err = ptrace_hbp_fill_attr_ctrl(note_type, ctrl, &attr);
334 	if (err)
335 		return err;
336 
337 	return modify_user_hw_breakpoint(bp, &attr);
338 }
339 
340 static int ptrace_hbp_set_addr(unsigned int note_type,
341 			       struct task_struct *tsk,
342 			       unsigned long idx,
343 			       u64 addr)
344 {
345 	int err;
346 	struct perf_event *bp;
347 	struct perf_event_attr attr;
348 
349 	bp = ptrace_hbp_get_initialised_bp(note_type, tsk, idx);
350 	if (IS_ERR(bp)) {
351 		err = PTR_ERR(bp);
352 		return err;
353 	}
354 
355 	attr = bp->attr;
356 	attr.bp_addr = addr;
357 	err = modify_user_hw_breakpoint(bp, &attr);
358 	return err;
359 }
360 
361 #define PTRACE_HBP_ADDR_SZ	sizeof(u64)
362 #define PTRACE_HBP_CTRL_SZ	sizeof(u32)
363 #define PTRACE_HBP_PAD_SZ	sizeof(u32)
364 
365 static int hw_break_get(struct task_struct *target,
366 			const struct user_regset *regset,
367 			unsigned int pos, unsigned int count,
368 			void *kbuf, void __user *ubuf)
369 {
370 	unsigned int note_type = regset->core_note_type;
371 	int ret, idx = 0, offset, limit;
372 	u32 info, ctrl;
373 	u64 addr;
374 
375 	/* Resource info */
376 	ret = ptrace_hbp_get_resource_info(note_type, &info);
377 	if (ret)
378 		return ret;
379 
380 	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &info, 0,
381 				  sizeof(info));
382 	if (ret)
383 		return ret;
384 
385 	/* Pad */
386 	offset = offsetof(struct user_hwdebug_state, pad);
387 	ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf, offset,
388 				       offset + PTRACE_HBP_PAD_SZ);
389 	if (ret)
390 		return ret;
391 
392 	/* (address, ctrl) registers */
393 	offset = offsetof(struct user_hwdebug_state, dbg_regs);
394 	limit = regset->n * regset->size;
395 	while (count && offset < limit) {
396 		ret = ptrace_hbp_get_addr(note_type, target, idx, &addr);
397 		if (ret)
398 			return ret;
399 		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &addr,
400 					  offset, offset + PTRACE_HBP_ADDR_SZ);
401 		if (ret)
402 			return ret;
403 		offset += PTRACE_HBP_ADDR_SZ;
404 
405 		ret = ptrace_hbp_get_ctrl(note_type, target, idx, &ctrl);
406 		if (ret)
407 			return ret;
408 		ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, &ctrl,
409 					  offset, offset + PTRACE_HBP_CTRL_SZ);
410 		if (ret)
411 			return ret;
412 		offset += PTRACE_HBP_CTRL_SZ;
413 
414 		ret = user_regset_copyout_zero(&pos, &count, &kbuf, &ubuf,
415 					       offset,
416 					       offset + PTRACE_HBP_PAD_SZ);
417 		if (ret)
418 			return ret;
419 		offset += PTRACE_HBP_PAD_SZ;
420 		idx++;
421 	}
422 
423 	return 0;
424 }
425 
426 static int hw_break_set(struct task_struct *target,
427 			const struct user_regset *regset,
428 			unsigned int pos, unsigned int count,
429 			const void *kbuf, const void __user *ubuf)
430 {
431 	unsigned int note_type = regset->core_note_type;
432 	int ret, idx = 0, offset, limit;
433 	u32 ctrl;
434 	u64 addr;
435 
436 	/* Resource info and pad */
437 	offset = offsetof(struct user_hwdebug_state, dbg_regs);
438 	ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf, 0, offset);
439 	if (ret)
440 		return ret;
441 
442 	/* (address, ctrl) registers */
443 	limit = regset->n * regset->size;
444 	while (count && offset < limit) {
445 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &addr,
446 					 offset, offset + PTRACE_HBP_ADDR_SZ);
447 		if (ret)
448 			return ret;
449 		ret = ptrace_hbp_set_addr(note_type, target, idx, addr);
450 		if (ret)
451 			return ret;
452 		offset += PTRACE_HBP_ADDR_SZ;
453 
454 		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &ctrl,
455 					 offset, offset + PTRACE_HBP_CTRL_SZ);
456 		if (ret)
457 			return ret;
458 		ret = ptrace_hbp_set_ctrl(note_type, target, idx, ctrl);
459 		if (ret)
460 			return ret;
461 		offset += PTRACE_HBP_CTRL_SZ;
462 
463 		ret = user_regset_copyin_ignore(&pos, &count, &kbuf, &ubuf,
464 						offset,
465 						offset + PTRACE_HBP_PAD_SZ);
466 		if (ret)
467 			return ret;
468 		offset += PTRACE_HBP_PAD_SZ;
469 		idx++;
470 	}
471 
472 	return 0;
473 }
474 #endif	/* CONFIG_HAVE_HW_BREAKPOINT */
475 
476 static int gpr_get(struct task_struct *target,
477 		   const struct user_regset *regset,
478 		   unsigned int pos, unsigned int count,
479 		   void *kbuf, void __user *ubuf)
480 {
481 	struct user_pt_regs *uregs = &task_pt_regs(target)->user_regs;
482 	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0, -1);
483 }
484 
485 static int gpr_set(struct task_struct *target, const struct user_regset *regset,
486 		   unsigned int pos, unsigned int count,
487 		   const void *kbuf, const void __user *ubuf)
488 {
489 	int ret;
490 	struct user_pt_regs newregs;
491 
492 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newregs, 0, -1);
493 	if (ret)
494 		return ret;
495 
496 	if (!valid_user_regs(&newregs))
497 		return -EINVAL;
498 
499 	task_pt_regs(target)->user_regs = newregs;
500 	return 0;
501 }
502 
503 /*
504  * TODO: update fp accessors for lazy context switching (sync/flush hwstate)
505  */
506 static int fpr_get(struct task_struct *target, const struct user_regset *regset,
507 		   unsigned int pos, unsigned int count,
508 		   void *kbuf, void __user *ubuf)
509 {
510 	struct user_fpsimd_state *uregs;
511 	uregs = &target->thread.fpsimd_state.user_fpsimd;
512 	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0, -1);
513 }
514 
515 static int fpr_set(struct task_struct *target, const struct user_regset *regset,
516 		   unsigned int pos, unsigned int count,
517 		   const void *kbuf, const void __user *ubuf)
518 {
519 	int ret;
520 	struct user_fpsimd_state newstate;
521 
522 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newstate, 0, -1);
523 	if (ret)
524 		return ret;
525 
526 	target->thread.fpsimd_state.user_fpsimd = newstate;
527 	fpsimd_flush_task_state(target);
528 	return ret;
529 }
530 
531 static int tls_get(struct task_struct *target, const struct user_regset *regset,
532 		   unsigned int pos, unsigned int count,
533 		   void *kbuf, void __user *ubuf)
534 {
535 	unsigned long *tls = &target->thread.tp_value;
536 	return user_regset_copyout(&pos, &count, &kbuf, &ubuf, tls, 0, -1);
537 }
538 
539 static int tls_set(struct task_struct *target, const struct user_regset *regset,
540 		   unsigned int pos, unsigned int count,
541 		   const void *kbuf, const void __user *ubuf)
542 {
543 	int ret;
544 	unsigned long tls;
545 
546 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &tls, 0, -1);
547 	if (ret)
548 		return ret;
549 
550 	target->thread.tp_value = tls;
551 	return ret;
552 }
553 
554 enum aarch64_regset {
555 	REGSET_GPR,
556 	REGSET_FPR,
557 	REGSET_TLS,
558 #ifdef CONFIG_HAVE_HW_BREAKPOINT
559 	REGSET_HW_BREAK,
560 	REGSET_HW_WATCH,
561 #endif
562 };
563 
564 static const struct user_regset aarch64_regsets[] = {
565 	[REGSET_GPR] = {
566 		.core_note_type = NT_PRSTATUS,
567 		.n = sizeof(struct user_pt_regs) / sizeof(u64),
568 		.size = sizeof(u64),
569 		.align = sizeof(u64),
570 		.get = gpr_get,
571 		.set = gpr_set
572 	},
573 	[REGSET_FPR] = {
574 		.core_note_type = NT_PRFPREG,
575 		.n = sizeof(struct user_fpsimd_state) / sizeof(u32),
576 		/*
577 		 * We pretend we have 32-bit registers because the fpsr and
578 		 * fpcr are 32-bits wide.
579 		 */
580 		.size = sizeof(u32),
581 		.align = sizeof(u32),
582 		.get = fpr_get,
583 		.set = fpr_set
584 	},
585 	[REGSET_TLS] = {
586 		.core_note_type = NT_ARM_TLS,
587 		.n = 1,
588 		.size = sizeof(void *),
589 		.align = sizeof(void *),
590 		.get = tls_get,
591 		.set = tls_set,
592 	},
593 #ifdef CONFIG_HAVE_HW_BREAKPOINT
594 	[REGSET_HW_BREAK] = {
595 		.core_note_type = NT_ARM_HW_BREAK,
596 		.n = sizeof(struct user_hwdebug_state) / sizeof(u32),
597 		.size = sizeof(u32),
598 		.align = sizeof(u32),
599 		.get = hw_break_get,
600 		.set = hw_break_set,
601 	},
602 	[REGSET_HW_WATCH] = {
603 		.core_note_type = NT_ARM_HW_WATCH,
604 		.n = sizeof(struct user_hwdebug_state) / sizeof(u32),
605 		.size = sizeof(u32),
606 		.align = sizeof(u32),
607 		.get = hw_break_get,
608 		.set = hw_break_set,
609 	},
610 #endif
611 };
612 
613 static const struct user_regset_view user_aarch64_view = {
614 	.name = "aarch64", .e_machine = EM_AARCH64,
615 	.regsets = aarch64_regsets, .n = ARRAY_SIZE(aarch64_regsets)
616 };
617 
618 #ifdef CONFIG_COMPAT
619 #include <linux/compat.h>
620 
621 enum compat_regset {
622 	REGSET_COMPAT_GPR,
623 	REGSET_COMPAT_VFP,
624 };
625 
626 static int compat_gpr_get(struct task_struct *target,
627 			  const struct user_regset *regset,
628 			  unsigned int pos, unsigned int count,
629 			  void *kbuf, void __user *ubuf)
630 {
631 	int ret = 0;
632 	unsigned int i, start, num_regs;
633 
634 	/* Calculate the number of AArch32 registers contained in count */
635 	num_regs = count / regset->size;
636 
637 	/* Convert pos into an register number */
638 	start = pos / regset->size;
639 
640 	if (start + num_regs > regset->n)
641 		return -EIO;
642 
643 	for (i = 0; i < num_regs; ++i) {
644 		unsigned int idx = start + i;
645 		compat_ulong_t reg;
646 
647 		switch (idx) {
648 		case 15:
649 			reg = task_pt_regs(target)->pc;
650 			break;
651 		case 16:
652 			reg = task_pt_regs(target)->pstate;
653 			break;
654 		case 17:
655 			reg = task_pt_regs(target)->orig_x0;
656 			break;
657 		default:
658 			reg = task_pt_regs(target)->regs[idx];
659 		}
660 
661 		if (kbuf) {
662 			memcpy(kbuf, &reg, sizeof(reg));
663 			kbuf += sizeof(reg);
664 		} else {
665 			ret = copy_to_user(ubuf, &reg, sizeof(reg));
666 			if (ret) {
667 				ret = -EFAULT;
668 				break;
669 			}
670 
671 			ubuf += sizeof(reg);
672 		}
673 	}
674 
675 	return ret;
676 }
677 
678 static int compat_gpr_set(struct task_struct *target,
679 			  const struct user_regset *regset,
680 			  unsigned int pos, unsigned int count,
681 			  const void *kbuf, const void __user *ubuf)
682 {
683 	struct pt_regs newregs;
684 	int ret = 0;
685 	unsigned int i, start, num_regs;
686 
687 	/* Calculate the number of AArch32 registers contained in count */
688 	num_regs = count / regset->size;
689 
690 	/* Convert pos into an register number */
691 	start = pos / regset->size;
692 
693 	if (start + num_regs > regset->n)
694 		return -EIO;
695 
696 	newregs = *task_pt_regs(target);
697 
698 	for (i = 0; i < num_regs; ++i) {
699 		unsigned int idx = start + i;
700 		compat_ulong_t reg;
701 
702 		if (kbuf) {
703 			memcpy(&reg, kbuf, sizeof(reg));
704 			kbuf += sizeof(reg);
705 		} else {
706 			ret = copy_from_user(&reg, ubuf, sizeof(reg));
707 			if (ret) {
708 				ret = -EFAULT;
709 				break;
710 			}
711 
712 			ubuf += sizeof(reg);
713 		}
714 
715 		switch (idx) {
716 		case 15:
717 			newregs.pc = reg;
718 			break;
719 		case 16:
720 			newregs.pstate = reg;
721 			break;
722 		case 17:
723 			newregs.orig_x0 = reg;
724 			break;
725 		default:
726 			newregs.regs[idx] = reg;
727 		}
728 
729 	}
730 
731 	if (valid_user_regs(&newregs.user_regs))
732 		*task_pt_regs(target) = newregs;
733 	else
734 		ret = -EINVAL;
735 
736 	return ret;
737 }
738 
739 static int compat_vfp_get(struct task_struct *target,
740 			  const struct user_regset *regset,
741 			  unsigned int pos, unsigned int count,
742 			  void *kbuf, void __user *ubuf)
743 {
744 	struct user_fpsimd_state *uregs;
745 	compat_ulong_t fpscr;
746 	int ret;
747 
748 	uregs = &target->thread.fpsimd_state.user_fpsimd;
749 
750 	/*
751 	 * The VFP registers are packed into the fpsimd_state, so they all sit
752 	 * nicely together for us. We just need to create the fpscr separately.
753 	 */
754 	ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0,
755 				  VFP_STATE_SIZE - sizeof(compat_ulong_t));
756 
757 	if (count && !ret) {
758 		fpscr = (uregs->fpsr & VFP_FPSCR_STAT_MASK) |
759 			(uregs->fpcr & VFP_FPSCR_CTRL_MASK);
760 		ret = put_user(fpscr, (compat_ulong_t *)ubuf);
761 	}
762 
763 	return ret;
764 }
765 
766 static int compat_vfp_set(struct task_struct *target,
767 			  const struct user_regset *regset,
768 			  unsigned int pos, unsigned int count,
769 			  const void *kbuf, const void __user *ubuf)
770 {
771 	struct user_fpsimd_state *uregs;
772 	compat_ulong_t fpscr;
773 	int ret;
774 
775 	if (pos + count > VFP_STATE_SIZE)
776 		return -EIO;
777 
778 	uregs = &target->thread.fpsimd_state.user_fpsimd;
779 
780 	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, uregs, 0,
781 				 VFP_STATE_SIZE - sizeof(compat_ulong_t));
782 
783 	if (count && !ret) {
784 		ret = get_user(fpscr, (compat_ulong_t *)ubuf);
785 		uregs->fpsr = fpscr & VFP_FPSCR_STAT_MASK;
786 		uregs->fpcr = fpscr & VFP_FPSCR_CTRL_MASK;
787 	}
788 
789 	fpsimd_flush_task_state(target);
790 	return ret;
791 }
792 
793 static const struct user_regset aarch32_regsets[] = {
794 	[REGSET_COMPAT_GPR] = {
795 		.core_note_type = NT_PRSTATUS,
796 		.n = COMPAT_ELF_NGREG,
797 		.size = sizeof(compat_elf_greg_t),
798 		.align = sizeof(compat_elf_greg_t),
799 		.get = compat_gpr_get,
800 		.set = compat_gpr_set
801 	},
802 	[REGSET_COMPAT_VFP] = {
803 		.core_note_type = NT_ARM_VFP,
804 		.n = VFP_STATE_SIZE / sizeof(compat_ulong_t),
805 		.size = sizeof(compat_ulong_t),
806 		.align = sizeof(compat_ulong_t),
807 		.get = compat_vfp_get,
808 		.set = compat_vfp_set
809 	},
810 };
811 
812 static const struct user_regset_view user_aarch32_view = {
813 	.name = "aarch32", .e_machine = EM_ARM,
814 	.regsets = aarch32_regsets, .n = ARRAY_SIZE(aarch32_regsets)
815 };
816 
817 static int compat_ptrace_read_user(struct task_struct *tsk, compat_ulong_t off,
818 				   compat_ulong_t __user *ret)
819 {
820 	compat_ulong_t tmp;
821 
822 	if (off & 3)
823 		return -EIO;
824 
825 	if (off == COMPAT_PT_TEXT_ADDR)
826 		tmp = tsk->mm->start_code;
827 	else if (off == COMPAT_PT_DATA_ADDR)
828 		tmp = tsk->mm->start_data;
829 	else if (off == COMPAT_PT_TEXT_END_ADDR)
830 		tmp = tsk->mm->end_code;
831 	else if (off < sizeof(compat_elf_gregset_t))
832 		return copy_regset_to_user(tsk, &user_aarch32_view,
833 					   REGSET_COMPAT_GPR, off,
834 					   sizeof(compat_ulong_t), ret);
835 	else if (off >= COMPAT_USER_SZ)
836 		return -EIO;
837 	else
838 		tmp = 0;
839 
840 	return put_user(tmp, ret);
841 }
842 
843 static int compat_ptrace_write_user(struct task_struct *tsk, compat_ulong_t off,
844 				    compat_ulong_t val)
845 {
846 	int ret;
847 	mm_segment_t old_fs = get_fs();
848 
849 	if (off & 3 || off >= COMPAT_USER_SZ)
850 		return -EIO;
851 
852 	if (off >= sizeof(compat_elf_gregset_t))
853 		return 0;
854 
855 	set_fs(KERNEL_DS);
856 	ret = copy_regset_from_user(tsk, &user_aarch32_view,
857 				    REGSET_COMPAT_GPR, off,
858 				    sizeof(compat_ulong_t),
859 				    &val);
860 	set_fs(old_fs);
861 
862 	return ret;
863 }
864 
865 #ifdef CONFIG_HAVE_HW_BREAKPOINT
866 
867 /*
868  * Convert a virtual register number into an index for a thread_info
869  * breakpoint array. Breakpoints are identified using positive numbers
870  * whilst watchpoints are negative. The registers are laid out as pairs
871  * of (address, control), each pair mapping to a unique hw_breakpoint struct.
872  * Register 0 is reserved for describing resource information.
873  */
874 static int compat_ptrace_hbp_num_to_idx(compat_long_t num)
875 {
876 	return (abs(num) - 1) >> 1;
877 }
878 
879 static int compat_ptrace_hbp_get_resource_info(u32 *kdata)
880 {
881 	u8 num_brps, num_wrps, debug_arch, wp_len;
882 	u32 reg = 0;
883 
884 	num_brps	= hw_breakpoint_slots(TYPE_INST);
885 	num_wrps	= hw_breakpoint_slots(TYPE_DATA);
886 
887 	debug_arch	= debug_monitors_arch();
888 	wp_len		= 8;
889 	reg		|= debug_arch;
890 	reg		<<= 8;
891 	reg		|= wp_len;
892 	reg		<<= 8;
893 	reg		|= num_wrps;
894 	reg		<<= 8;
895 	reg		|= num_brps;
896 
897 	*kdata = reg;
898 	return 0;
899 }
900 
901 static int compat_ptrace_hbp_get(unsigned int note_type,
902 				 struct task_struct *tsk,
903 				 compat_long_t num,
904 				 u32 *kdata)
905 {
906 	u64 addr = 0;
907 	u32 ctrl = 0;
908 
909 	int err, idx = compat_ptrace_hbp_num_to_idx(num);;
910 
911 	if (num & 1) {
912 		err = ptrace_hbp_get_addr(note_type, tsk, idx, &addr);
913 		*kdata = (u32)addr;
914 	} else {
915 		err = ptrace_hbp_get_ctrl(note_type, tsk, idx, &ctrl);
916 		*kdata = ctrl;
917 	}
918 
919 	return err;
920 }
921 
922 static int compat_ptrace_hbp_set(unsigned int note_type,
923 				 struct task_struct *tsk,
924 				 compat_long_t num,
925 				 u32 *kdata)
926 {
927 	u64 addr;
928 	u32 ctrl;
929 
930 	int err, idx = compat_ptrace_hbp_num_to_idx(num);
931 
932 	if (num & 1) {
933 		addr = *kdata;
934 		err = ptrace_hbp_set_addr(note_type, tsk, idx, addr);
935 	} else {
936 		ctrl = *kdata;
937 		err = ptrace_hbp_set_ctrl(note_type, tsk, idx, ctrl);
938 	}
939 
940 	return err;
941 }
942 
943 static int compat_ptrace_gethbpregs(struct task_struct *tsk, compat_long_t num,
944 				    compat_ulong_t __user *data)
945 {
946 	int ret;
947 	u32 kdata;
948 	mm_segment_t old_fs = get_fs();
949 
950 	set_fs(KERNEL_DS);
951 	/* Watchpoint */
952 	if (num < 0) {
953 		ret = compat_ptrace_hbp_get(NT_ARM_HW_WATCH, tsk, num, &kdata);
954 	/* Resource info */
955 	} else if (num == 0) {
956 		ret = compat_ptrace_hbp_get_resource_info(&kdata);
957 	/* Breakpoint */
958 	} else {
959 		ret = compat_ptrace_hbp_get(NT_ARM_HW_BREAK, tsk, num, &kdata);
960 	}
961 	set_fs(old_fs);
962 
963 	if (!ret)
964 		ret = put_user(kdata, data);
965 
966 	return ret;
967 }
968 
969 static int compat_ptrace_sethbpregs(struct task_struct *tsk, compat_long_t num,
970 				    compat_ulong_t __user *data)
971 {
972 	int ret;
973 	u32 kdata = 0;
974 	mm_segment_t old_fs = get_fs();
975 
976 	if (num == 0)
977 		return 0;
978 
979 	ret = get_user(kdata, data);
980 	if (ret)
981 		return ret;
982 
983 	set_fs(KERNEL_DS);
984 	if (num < 0)
985 		ret = compat_ptrace_hbp_set(NT_ARM_HW_WATCH, tsk, num, &kdata);
986 	else
987 		ret = compat_ptrace_hbp_set(NT_ARM_HW_BREAK, tsk, num, &kdata);
988 	set_fs(old_fs);
989 
990 	return ret;
991 }
992 #endif	/* CONFIG_HAVE_HW_BREAKPOINT */
993 
994 long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
995 			compat_ulong_t caddr, compat_ulong_t cdata)
996 {
997 	unsigned long addr = caddr;
998 	unsigned long data = cdata;
999 	void __user *datap = compat_ptr(data);
1000 	int ret;
1001 
1002 	switch (request) {
1003 		case PTRACE_PEEKUSR:
1004 			ret = compat_ptrace_read_user(child, addr, datap);
1005 			break;
1006 
1007 		case PTRACE_POKEUSR:
1008 			ret = compat_ptrace_write_user(child, addr, data);
1009 			break;
1010 
1011 		case COMPAT_PTRACE_GETREGS:
1012 			ret = copy_regset_to_user(child,
1013 						  &user_aarch32_view,
1014 						  REGSET_COMPAT_GPR,
1015 						  0, sizeof(compat_elf_gregset_t),
1016 						  datap);
1017 			break;
1018 
1019 		case COMPAT_PTRACE_SETREGS:
1020 			ret = copy_regset_from_user(child,
1021 						    &user_aarch32_view,
1022 						    REGSET_COMPAT_GPR,
1023 						    0, sizeof(compat_elf_gregset_t),
1024 						    datap);
1025 			break;
1026 
1027 		case COMPAT_PTRACE_GET_THREAD_AREA:
1028 			ret = put_user((compat_ulong_t)child->thread.tp_value,
1029 				       (compat_ulong_t __user *)datap);
1030 			break;
1031 
1032 		case COMPAT_PTRACE_SET_SYSCALL:
1033 			task_pt_regs(child)->syscallno = data;
1034 			ret = 0;
1035 			break;
1036 
1037 		case COMPAT_PTRACE_GETVFPREGS:
1038 			ret = copy_regset_to_user(child,
1039 						  &user_aarch32_view,
1040 						  REGSET_COMPAT_VFP,
1041 						  0, VFP_STATE_SIZE,
1042 						  datap);
1043 			break;
1044 
1045 		case COMPAT_PTRACE_SETVFPREGS:
1046 			ret = copy_regset_from_user(child,
1047 						    &user_aarch32_view,
1048 						    REGSET_COMPAT_VFP,
1049 						    0, VFP_STATE_SIZE,
1050 						    datap);
1051 			break;
1052 
1053 #ifdef CONFIG_HAVE_HW_BREAKPOINT
1054 		case COMPAT_PTRACE_GETHBPREGS:
1055 			ret = compat_ptrace_gethbpregs(child, addr, datap);
1056 			break;
1057 
1058 		case COMPAT_PTRACE_SETHBPREGS:
1059 			ret = compat_ptrace_sethbpregs(child, addr, datap);
1060 			break;
1061 #endif
1062 
1063 		default:
1064 			ret = compat_ptrace_request(child, request, addr,
1065 						    data);
1066 			break;
1067 	}
1068 
1069 	return ret;
1070 }
1071 #endif /* CONFIG_COMPAT */
1072 
1073 const struct user_regset_view *task_user_regset_view(struct task_struct *task)
1074 {
1075 #ifdef CONFIG_COMPAT
1076 	if (is_compat_thread(task_thread_info(task)))
1077 		return &user_aarch32_view;
1078 #endif
1079 	return &user_aarch64_view;
1080 }
1081 
1082 long arch_ptrace(struct task_struct *child, long request,
1083 		 unsigned long addr, unsigned long data)
1084 {
1085 	return ptrace_request(child, request, addr, data);
1086 }
1087 
1088 enum ptrace_syscall_dir {
1089 	PTRACE_SYSCALL_ENTER = 0,
1090 	PTRACE_SYSCALL_EXIT,
1091 };
1092 
1093 static void tracehook_report_syscall(struct pt_regs *regs,
1094 				     enum ptrace_syscall_dir dir)
1095 {
1096 	int regno;
1097 	unsigned long saved_reg;
1098 
1099 	/*
1100 	 * A scratch register (ip(r12) on AArch32, x7 on AArch64) is
1101 	 * used to denote syscall entry/exit:
1102 	 */
1103 	regno = (is_compat_task() ? 12 : 7);
1104 	saved_reg = regs->regs[regno];
1105 	regs->regs[regno] = dir;
1106 
1107 	if (dir == PTRACE_SYSCALL_EXIT)
1108 		tracehook_report_syscall_exit(regs, 0);
1109 	else if (tracehook_report_syscall_entry(regs))
1110 		regs->syscallno = ~0UL;
1111 
1112 	regs->regs[regno] = saved_reg;
1113 }
1114 
1115 asmlinkage int syscall_trace_enter(struct pt_regs *regs)
1116 {
1117 	if (test_thread_flag(TIF_SYSCALL_TRACE))
1118 		tracehook_report_syscall(regs, PTRACE_SYSCALL_ENTER);
1119 
1120 	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
1121 		trace_sys_enter(regs, regs->syscallno);
1122 
1123 	audit_syscall_entry(regs->syscallno, regs->orig_x0, regs->regs[1],
1124 			    regs->regs[2], regs->regs[3]);
1125 
1126 	return regs->syscallno;
1127 }
1128 
1129 asmlinkage void syscall_trace_exit(struct pt_regs *regs)
1130 {
1131 	audit_syscall_exit(regs);
1132 
1133 	if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
1134 		trace_sys_exit(regs, regs_return_value(regs));
1135 
1136 	if (test_thread_flag(TIF_SYSCALL_TRACE))
1137 		tracehook_report_syscall(regs, PTRACE_SYSCALL_EXIT);
1138 }
1139