xref: /openbmc/linux/arch/ia64/kernel/ptrace.c (revision 7f9321ff)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Kernel support for the ptrace() and syscall tracing interfaces.
4  *
5  * Copyright (C) 1999-2005 Hewlett-Packard Co
6  *	David Mosberger-Tang <davidm@hpl.hp.com>
7  * Copyright (C) 2006 Intel Co
8  *  2006-08-12	- IA64 Native Utrace implementation support added by
9  *	Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
10  *
11  * Derived from the x86 and Alpha versions.
12  */
13 #include <linux/kernel.h>
14 #include <linux/sched.h>
15 #include <linux/sched/task.h>
16 #include <linux/sched/task_stack.h>
17 #include <linux/mm.h>
18 #include <linux/errno.h>
19 #include <linux/ptrace.h>
20 #include <linux/user.h>
21 #include <linux/security.h>
22 #include <linux/audit.h>
23 #include <linux/signal.h>
24 #include <linux/regset.h>
25 #include <linux/elf.h>
26 #include <linux/tracehook.h>
27 
28 #include <asm/processor.h>
29 #include <asm/ptrace_offsets.h>
30 #include <asm/rse.h>
31 #include <linux/uaccess.h>
32 #include <asm/unwind.h>
33 
34 #include "entry.h"
35 
36 /*
37  * Bits in the PSR that we allow ptrace() to change:
38  *	be, up, ac, mfl, mfh (the user mask; five bits total)
39  *	db (debug breakpoint fault; one bit)
40  *	id (instruction debug fault disable; one bit)
41  *	dd (data debug fault disable; one bit)
42  *	ri (restart instruction; two bits)
43  *	is (instruction set; one bit)
44  */
45 #define IPSR_MASK (IA64_PSR_UM | IA64_PSR_DB | IA64_PSR_IS	\
46 		   | IA64_PSR_ID | IA64_PSR_DD | IA64_PSR_RI)
47 
48 #define MASK(nbits)	((1UL << (nbits)) - 1)	/* mask with NBITS bits set */
49 #define PFM_MASK	MASK(38)
50 
51 #define PTRACE_DEBUG	0
52 
53 #if PTRACE_DEBUG
54 # define dprintk(format...)	printk(format)
55 # define inline
56 #else
57 # define dprintk(format...)
58 #endif
59 
60 /* Return TRUE if PT was created due to kernel-entry via a system-call.  */
61 
62 static inline int
63 in_syscall (struct pt_regs *pt)
64 {
65 	return (long) pt->cr_ifs >= 0;
66 }
67 
68 /*
69  * Collect the NaT bits for r1-r31 from scratch_unat and return a NaT
70  * bitset where bit i is set iff the NaT bit of register i is set.
71  */
72 unsigned long
73 ia64_get_scratch_nat_bits (struct pt_regs *pt, unsigned long scratch_unat)
74 {
75 #	define GET_BITS(first, last, unat)				\
76 	({								\
77 		unsigned long bit = ia64_unat_pos(&pt->r##first);	\
78 		unsigned long nbits = (last - first + 1);		\
79 		unsigned long mask = MASK(nbits) << first;		\
80 		unsigned long dist;					\
81 		if (bit < first)					\
82 			dist = 64 + bit - first;			\
83 		else							\
84 			dist = bit - first;				\
85 		ia64_rotr(unat, dist) & mask;				\
86 	})
87 	unsigned long val;
88 
89 	/*
90 	 * Registers that are stored consecutively in struct pt_regs
91 	 * can be handled in parallel.  If the register order in
92 	 * struct_pt_regs changes, this code MUST be updated.
93 	 */
94 	val  = GET_BITS( 1,  1, scratch_unat);
95 	val |= GET_BITS( 2,  3, scratch_unat);
96 	val |= GET_BITS(12, 13, scratch_unat);
97 	val |= GET_BITS(14, 14, scratch_unat);
98 	val |= GET_BITS(15, 15, scratch_unat);
99 	val |= GET_BITS( 8, 11, scratch_unat);
100 	val |= GET_BITS(16, 31, scratch_unat);
101 	return val;
102 
103 #	undef GET_BITS
104 }
105 
106 /*
107  * Set the NaT bits for the scratch registers according to NAT and
108  * return the resulting unat (assuming the scratch registers are
109  * stored in PT).
110  */
111 unsigned long
112 ia64_put_scratch_nat_bits (struct pt_regs *pt, unsigned long nat)
113 {
114 #	define PUT_BITS(first, last, nat)				\
115 	({								\
116 		unsigned long bit = ia64_unat_pos(&pt->r##first);	\
117 		unsigned long nbits = (last - first + 1);		\
118 		unsigned long mask = MASK(nbits) << first;		\
119 		long dist;						\
120 		if (bit < first)					\
121 			dist = 64 + bit - first;			\
122 		else							\
123 			dist = bit - first;				\
124 		ia64_rotl(nat & mask, dist);				\
125 	})
126 	unsigned long scratch_unat;
127 
128 	/*
129 	 * Registers that are stored consecutively in struct pt_regs
130 	 * can be handled in parallel.  If the register order in
131 	 * struct_pt_regs changes, this code MUST be updated.
132 	 */
133 	scratch_unat  = PUT_BITS( 1,  1, nat);
134 	scratch_unat |= PUT_BITS( 2,  3, nat);
135 	scratch_unat |= PUT_BITS(12, 13, nat);
136 	scratch_unat |= PUT_BITS(14, 14, nat);
137 	scratch_unat |= PUT_BITS(15, 15, nat);
138 	scratch_unat |= PUT_BITS( 8, 11, nat);
139 	scratch_unat |= PUT_BITS(16, 31, nat);
140 
141 	return scratch_unat;
142 
143 #	undef PUT_BITS
144 }
145 
146 #define IA64_MLX_TEMPLATE	0x2
147 #define IA64_MOVL_OPCODE	6
148 
149 void
150 ia64_increment_ip (struct pt_regs *regs)
151 {
152 	unsigned long w0, ri = ia64_psr(regs)->ri + 1;
153 
154 	if (ri > 2) {
155 		ri = 0;
156 		regs->cr_iip += 16;
157 	} else if (ri == 2) {
158 		get_user(w0, (char __user *) regs->cr_iip + 0);
159 		if (((w0 >> 1) & 0xf) == IA64_MLX_TEMPLATE) {
160 			/*
161 			 * rfi'ing to slot 2 of an MLX bundle causes
162 			 * an illegal operation fault.  We don't want
163 			 * that to happen...
164 			 */
165 			ri = 0;
166 			regs->cr_iip += 16;
167 		}
168 	}
169 	ia64_psr(regs)->ri = ri;
170 }
171 
172 void
173 ia64_decrement_ip (struct pt_regs *regs)
174 {
175 	unsigned long w0, ri = ia64_psr(regs)->ri - 1;
176 
177 	if (ia64_psr(regs)->ri == 0) {
178 		regs->cr_iip -= 16;
179 		ri = 2;
180 		get_user(w0, (char __user *) regs->cr_iip + 0);
181 		if (((w0 >> 1) & 0xf) == IA64_MLX_TEMPLATE) {
182 			/*
183 			 * rfi'ing to slot 2 of an MLX bundle causes
184 			 * an illegal operation fault.  We don't want
185 			 * that to happen...
186 			 */
187 			ri = 1;
188 		}
189 	}
190 	ia64_psr(regs)->ri = ri;
191 }
192 
193 /*
194  * This routine is used to read an rnat bits that are stored on the
195  * kernel backing store.  Since, in general, the alignment of the user
196  * and kernel are different, this is not completely trivial.  In
197  * essence, we need to construct the user RNAT based on up to two
198  * kernel RNAT values and/or the RNAT value saved in the child's
199  * pt_regs.
200  *
201  * user rbs
202  *
203  * +--------+ <-- lowest address
204  * | slot62 |
205  * +--------+
206  * |  rnat  | 0x....1f8
207  * +--------+
208  * | slot00 | \
209  * +--------+ |
210  * | slot01 | > child_regs->ar_rnat
211  * +--------+ |
212  * | slot02 | /				kernel rbs
213  * +--------+				+--------+
214  *	    <- child_regs->ar_bspstore	| slot61 | <-- krbs
215  * +- - - - +				+--------+
216  *					| slot62 |
217  * +- - - - +				+--------+
218  *					|  rnat	 |
219  * +- - - - +				+--------+
220  *   vrnat				| slot00 |
221  * +- - - - +				+--------+
222  *					=	 =
223  *					+--------+
224  *					| slot00 | \
225  *					+--------+ |
226  *					| slot01 | > child_stack->ar_rnat
227  *					+--------+ |
228  *					| slot02 | /
229  *					+--------+
230  *						  <--- child_stack->ar_bspstore
231  *
232  * The way to think of this code is as follows: bit 0 in the user rnat
233  * corresponds to some bit N (0 <= N <= 62) in one of the kernel rnat
234  * value.  The kernel rnat value holding this bit is stored in
235  * variable rnat0.  rnat1 is loaded with the kernel rnat value that
236  * form the upper bits of the user rnat value.
237  *
238  * Boundary cases:
239  *
240  * o when reading the rnat "below" the first rnat slot on the kernel
241  *   backing store, rnat0/rnat1 are set to 0 and the low order bits are
242  *   merged in from pt->ar_rnat.
243  *
244  * o when reading the rnat "above" the last rnat slot on the kernel
245  *   backing store, rnat0/rnat1 gets its value from sw->ar_rnat.
246  */
247 static unsigned long
248 get_rnat (struct task_struct *task, struct switch_stack *sw,
249 	  unsigned long *krbs, unsigned long *urnat_addr,
250 	  unsigned long *urbs_end)
251 {
252 	unsigned long rnat0 = 0, rnat1 = 0, urnat = 0, *slot0_kaddr;
253 	unsigned long umask = 0, mask, m;
254 	unsigned long *kbsp, *ubspstore, *rnat0_kaddr, *rnat1_kaddr, shift;
255 	long num_regs, nbits;
256 	struct pt_regs *pt;
257 
258 	pt = task_pt_regs(task);
259 	kbsp = (unsigned long *) sw->ar_bspstore;
260 	ubspstore = (unsigned long *) pt->ar_bspstore;
261 
262 	if (urbs_end < urnat_addr)
263 		nbits = ia64_rse_num_regs(urnat_addr - 63, urbs_end);
264 	else
265 		nbits = 63;
266 	mask = MASK(nbits);
267 	/*
268 	 * First, figure out which bit number slot 0 in user-land maps
269 	 * to in the kernel rnat.  Do this by figuring out how many
270 	 * register slots we're beyond the user's backingstore and
271 	 * then computing the equivalent address in kernel space.
272 	 */
273 	num_regs = ia64_rse_num_regs(ubspstore, urnat_addr + 1);
274 	slot0_kaddr = ia64_rse_skip_regs(krbs, num_regs);
275 	shift = ia64_rse_slot_num(slot0_kaddr);
276 	rnat1_kaddr = ia64_rse_rnat_addr(slot0_kaddr);
277 	rnat0_kaddr = rnat1_kaddr - 64;
278 
279 	if (ubspstore + 63 > urnat_addr) {
280 		/* some bits need to be merged in from pt->ar_rnat */
281 		umask = MASK(ia64_rse_slot_num(ubspstore)) & mask;
282 		urnat = (pt->ar_rnat & umask);
283 		mask &= ~umask;
284 		if (!mask)
285 			return urnat;
286 	}
287 
288 	m = mask << shift;
289 	if (rnat0_kaddr >= kbsp)
290 		rnat0 = sw->ar_rnat;
291 	else if (rnat0_kaddr > krbs)
292 		rnat0 = *rnat0_kaddr;
293 	urnat |= (rnat0 & m) >> shift;
294 
295 	m = mask >> (63 - shift);
296 	if (rnat1_kaddr >= kbsp)
297 		rnat1 = sw->ar_rnat;
298 	else if (rnat1_kaddr > krbs)
299 		rnat1 = *rnat1_kaddr;
300 	urnat |= (rnat1 & m) << (63 - shift);
301 	return urnat;
302 }
303 
304 /*
305  * The reverse of get_rnat.
306  */
307 static void
308 put_rnat (struct task_struct *task, struct switch_stack *sw,
309 	  unsigned long *krbs, unsigned long *urnat_addr, unsigned long urnat,
310 	  unsigned long *urbs_end)
311 {
312 	unsigned long rnat0 = 0, rnat1 = 0, *slot0_kaddr, umask = 0, mask, m;
313 	unsigned long *kbsp, *ubspstore, *rnat0_kaddr, *rnat1_kaddr, shift;
314 	long num_regs, nbits;
315 	struct pt_regs *pt;
316 	unsigned long cfm, *urbs_kargs;
317 
318 	pt = task_pt_regs(task);
319 	kbsp = (unsigned long *) sw->ar_bspstore;
320 	ubspstore = (unsigned long *) pt->ar_bspstore;
321 
322 	urbs_kargs = urbs_end;
323 	if (in_syscall(pt)) {
324 		/*
325 		 * If entered via syscall, don't allow user to set rnat bits
326 		 * for syscall args.
327 		 */
328 		cfm = pt->cr_ifs;
329 		urbs_kargs = ia64_rse_skip_regs(urbs_end, -(cfm & 0x7f));
330 	}
331 
332 	if (urbs_kargs >= urnat_addr)
333 		nbits = 63;
334 	else {
335 		if ((urnat_addr - 63) >= urbs_kargs)
336 			return;
337 		nbits = ia64_rse_num_regs(urnat_addr - 63, urbs_kargs);
338 	}
339 	mask = MASK(nbits);
340 
341 	/*
342 	 * First, figure out which bit number slot 0 in user-land maps
343 	 * to in the kernel rnat.  Do this by figuring out how many
344 	 * register slots we're beyond the user's backingstore and
345 	 * then computing the equivalent address in kernel space.
346 	 */
347 	num_regs = ia64_rse_num_regs(ubspstore, urnat_addr + 1);
348 	slot0_kaddr = ia64_rse_skip_regs(krbs, num_regs);
349 	shift = ia64_rse_slot_num(slot0_kaddr);
350 	rnat1_kaddr = ia64_rse_rnat_addr(slot0_kaddr);
351 	rnat0_kaddr = rnat1_kaddr - 64;
352 
353 	if (ubspstore + 63 > urnat_addr) {
354 		/* some bits need to be place in pt->ar_rnat: */
355 		umask = MASK(ia64_rse_slot_num(ubspstore)) & mask;
356 		pt->ar_rnat = (pt->ar_rnat & ~umask) | (urnat & umask);
357 		mask &= ~umask;
358 		if (!mask)
359 			return;
360 	}
361 	/*
362 	 * Note: Section 11.1 of the EAS guarantees that bit 63 of an
363 	 * rnat slot is ignored. so we don't have to clear it here.
364 	 */
365 	rnat0 = (urnat << shift);
366 	m = mask << shift;
367 	if (rnat0_kaddr >= kbsp)
368 		sw->ar_rnat = (sw->ar_rnat & ~m) | (rnat0 & m);
369 	else if (rnat0_kaddr > krbs)
370 		*rnat0_kaddr = ((*rnat0_kaddr & ~m) | (rnat0 & m));
371 
372 	rnat1 = (urnat >> (63 - shift));
373 	m = mask >> (63 - shift);
374 	if (rnat1_kaddr >= kbsp)
375 		sw->ar_rnat = (sw->ar_rnat & ~m) | (rnat1 & m);
376 	else if (rnat1_kaddr > krbs)
377 		*rnat1_kaddr = ((*rnat1_kaddr & ~m) | (rnat1 & m));
378 }
379 
380 static inline int
381 on_kernel_rbs (unsigned long addr, unsigned long bspstore,
382 	       unsigned long urbs_end)
383 {
384 	unsigned long *rnat_addr = ia64_rse_rnat_addr((unsigned long *)
385 						      urbs_end);
386 	return (addr >= bspstore && addr <= (unsigned long) rnat_addr);
387 }
388 
389 /*
390  * Read a word from the user-level backing store of task CHILD.  ADDR
391  * is the user-level address to read the word from, VAL a pointer to
392  * the return value, and USER_BSP gives the end of the user-level
393  * backing store (i.e., it's the address that would be in ar.bsp after
394  * the user executed a "cover" instruction).
395  *
396  * This routine takes care of accessing the kernel register backing
397  * store for those registers that got spilled there.  It also takes
398  * care of calculating the appropriate RNaT collection words.
399  */
400 long
401 ia64_peek (struct task_struct *child, struct switch_stack *child_stack,
402 	   unsigned long user_rbs_end, unsigned long addr, long *val)
403 {
404 	unsigned long *bspstore, *krbs, regnum, *laddr, *urbs_end, *rnat_addr;
405 	struct pt_regs *child_regs;
406 	size_t copied;
407 	long ret;
408 
409 	urbs_end = (long *) user_rbs_end;
410 	laddr = (unsigned long *) addr;
411 	child_regs = task_pt_regs(child);
412 	bspstore = (unsigned long *) child_regs->ar_bspstore;
413 	krbs = (unsigned long *) child + IA64_RBS_OFFSET/8;
414 	if (on_kernel_rbs(addr, (unsigned long) bspstore,
415 			  (unsigned long) urbs_end))
416 	{
417 		/*
418 		 * Attempt to read the RBS in an area that's actually
419 		 * on the kernel RBS => read the corresponding bits in
420 		 * the kernel RBS.
421 		 */
422 		rnat_addr = ia64_rse_rnat_addr(laddr);
423 		ret = get_rnat(child, child_stack, krbs, rnat_addr, urbs_end);
424 
425 		if (laddr == rnat_addr) {
426 			/* return NaT collection word itself */
427 			*val = ret;
428 			return 0;
429 		}
430 
431 		if (((1UL << ia64_rse_slot_num(laddr)) & ret) != 0) {
432 			/*
433 			 * It is implementation dependent whether the
434 			 * data portion of a NaT value gets saved on a
435 			 * st8.spill or RSE spill (e.g., see EAS 2.6,
436 			 * 4.4.4.6 Register Spill and Fill).  To get
437 			 * consistent behavior across all possible
438 			 * IA-64 implementations, we return zero in
439 			 * this case.
440 			 */
441 			*val = 0;
442 			return 0;
443 		}
444 
445 		if (laddr < urbs_end) {
446 			/*
447 			 * The desired word is on the kernel RBS and
448 			 * is not a NaT.
449 			 */
450 			regnum = ia64_rse_num_regs(bspstore, laddr);
451 			*val = *ia64_rse_skip_regs(krbs, regnum);
452 			return 0;
453 		}
454 	}
455 	copied = access_process_vm(child, addr, &ret, sizeof(ret), FOLL_FORCE);
456 	if (copied != sizeof(ret))
457 		return -EIO;
458 	*val = ret;
459 	return 0;
460 }
461 
462 long
463 ia64_poke (struct task_struct *child, struct switch_stack *child_stack,
464 	   unsigned long user_rbs_end, unsigned long addr, long val)
465 {
466 	unsigned long *bspstore, *krbs, regnum, *laddr;
467 	unsigned long *urbs_end = (long *) user_rbs_end;
468 	struct pt_regs *child_regs;
469 
470 	laddr = (unsigned long *) addr;
471 	child_regs = task_pt_regs(child);
472 	bspstore = (unsigned long *) child_regs->ar_bspstore;
473 	krbs = (unsigned long *) child + IA64_RBS_OFFSET/8;
474 	if (on_kernel_rbs(addr, (unsigned long) bspstore,
475 			  (unsigned long) urbs_end))
476 	{
477 		/*
478 		 * Attempt to write the RBS in an area that's actually
479 		 * on the kernel RBS => write the corresponding bits
480 		 * in the kernel RBS.
481 		 */
482 		if (ia64_rse_is_rnat_slot(laddr))
483 			put_rnat(child, child_stack, krbs, laddr, val,
484 				 urbs_end);
485 		else {
486 			if (laddr < urbs_end) {
487 				regnum = ia64_rse_num_regs(bspstore, laddr);
488 				*ia64_rse_skip_regs(krbs, regnum) = val;
489 			}
490 		}
491 	} else if (access_process_vm(child, addr, &val, sizeof(val),
492 				FOLL_FORCE | FOLL_WRITE)
493 		   != sizeof(val))
494 		return -EIO;
495 	return 0;
496 }
497 
498 /*
499  * Calculate the address of the end of the user-level register backing
500  * store.  This is the address that would have been stored in ar.bsp
501  * if the user had executed a "cover" instruction right before
502  * entering the kernel.  If CFMP is not NULL, it is used to return the
503  * "current frame mask" that was active at the time the kernel was
504  * entered.
505  */
506 unsigned long
507 ia64_get_user_rbs_end (struct task_struct *child, struct pt_regs *pt,
508 		       unsigned long *cfmp)
509 {
510 	unsigned long *krbs, *bspstore, cfm = pt->cr_ifs;
511 	long ndirty;
512 
513 	krbs = (unsigned long *) child + IA64_RBS_OFFSET/8;
514 	bspstore = (unsigned long *) pt->ar_bspstore;
515 	ndirty = ia64_rse_num_regs(krbs, krbs + (pt->loadrs >> 19));
516 
517 	if (in_syscall(pt))
518 		ndirty += (cfm & 0x7f);
519 	else
520 		cfm &= ~(1UL << 63);	/* clear valid bit */
521 
522 	if (cfmp)
523 		*cfmp = cfm;
524 	return (unsigned long) ia64_rse_skip_regs(bspstore, ndirty);
525 }
526 
527 /*
528  * Synchronize (i.e, write) the RSE backing store living in kernel
529  * space to the VM of the CHILD task.  SW and PT are the pointers to
530  * the switch_stack and pt_regs structures, respectively.
531  * USER_RBS_END is the user-level address at which the backing store
532  * ends.
533  */
534 long
535 ia64_sync_user_rbs (struct task_struct *child, struct switch_stack *sw,
536 		    unsigned long user_rbs_start, unsigned long user_rbs_end)
537 {
538 	unsigned long addr, val;
539 	long ret;
540 
541 	/* now copy word for word from kernel rbs to user rbs: */
542 	for (addr = user_rbs_start; addr < user_rbs_end; addr += 8) {
543 		ret = ia64_peek(child, sw, user_rbs_end, addr, &val);
544 		if (ret < 0)
545 			return ret;
546 		if (access_process_vm(child, addr, &val, sizeof(val),
547 				FOLL_FORCE | FOLL_WRITE)
548 		    != sizeof(val))
549 			return -EIO;
550 	}
551 	return 0;
552 }
553 
554 static long
555 ia64_sync_kernel_rbs (struct task_struct *child, struct switch_stack *sw,
556 		unsigned long user_rbs_start, unsigned long user_rbs_end)
557 {
558 	unsigned long addr, val;
559 	long ret;
560 
561 	/* now copy word for word from user rbs to kernel rbs: */
562 	for (addr = user_rbs_start; addr < user_rbs_end; addr += 8) {
563 		if (access_process_vm(child, addr, &val, sizeof(val),
564 				FOLL_FORCE)
565 				!= sizeof(val))
566 			return -EIO;
567 
568 		ret = ia64_poke(child, sw, user_rbs_end, addr, val);
569 		if (ret < 0)
570 			return ret;
571 	}
572 	return 0;
573 }
574 
575 typedef long (*syncfunc_t)(struct task_struct *, struct switch_stack *,
576 			    unsigned long, unsigned long);
577 
578 static void do_sync_rbs(struct unw_frame_info *info, void *arg)
579 {
580 	struct pt_regs *pt;
581 	unsigned long urbs_end;
582 	syncfunc_t fn = arg;
583 
584 	if (unw_unwind_to_user(info) < 0)
585 		return;
586 	pt = task_pt_regs(info->task);
587 	urbs_end = ia64_get_user_rbs_end(info->task, pt, NULL);
588 
589 	fn(info->task, info->sw, pt->ar_bspstore, urbs_end);
590 }
591 
592 /*
593  * when a thread is stopped (ptraced), debugger might change thread's user
594  * stack (change memory directly), and we must avoid the RSE stored in kernel
595  * to override user stack (user space's RSE is newer than kernel's in the
596  * case). To workaround the issue, we copy kernel RSE to user RSE before the
597  * task is stopped, so user RSE has updated data.  we then copy user RSE to
598  * kernel after the task is resummed from traced stop and kernel will use the
599  * newer RSE to return to user. TIF_RESTORE_RSE is the flag to indicate we need
600  * synchronize user RSE to kernel.
601  */
602 void ia64_ptrace_stop(void)
603 {
604 	if (test_and_set_tsk_thread_flag(current, TIF_RESTORE_RSE))
605 		return;
606 	set_notify_resume(current);
607 	unw_init_running(do_sync_rbs, ia64_sync_user_rbs);
608 }
609 
610 /*
611  * This is called to read back the register backing store.
612  */
613 void ia64_sync_krbs(void)
614 {
615 	clear_tsk_thread_flag(current, TIF_RESTORE_RSE);
616 
617 	unw_init_running(do_sync_rbs, ia64_sync_kernel_rbs);
618 }
619 
620 /*
621  * After PTRACE_ATTACH, a thread's register backing store area in user
622  * space is assumed to contain correct data whenever the thread is
623  * stopped.  arch_ptrace_stop takes care of this on tracing stops.
624  * But if the child was already stopped for job control when we attach
625  * to it, then it might not ever get into ptrace_stop by the time we
626  * want to examine the user memory containing the RBS.
627  */
628 void
629 ptrace_attach_sync_user_rbs (struct task_struct *child)
630 {
631 	int stopped = 0;
632 	struct unw_frame_info info;
633 
634 	/*
635 	 * If the child is in TASK_STOPPED, we need to change that to
636 	 * TASK_TRACED momentarily while we operate on it.  This ensures
637 	 * that the child won't be woken up and return to user mode while
638 	 * we are doing the sync.  (It can only be woken up for SIGKILL.)
639 	 */
640 
641 	read_lock(&tasklist_lock);
642 	if (child->sighand) {
643 		spin_lock_irq(&child->sighand->siglock);
644 		if (child->state == TASK_STOPPED &&
645 		    !test_and_set_tsk_thread_flag(child, TIF_RESTORE_RSE)) {
646 			set_notify_resume(child);
647 
648 			child->state = TASK_TRACED;
649 			stopped = 1;
650 		}
651 		spin_unlock_irq(&child->sighand->siglock);
652 	}
653 	read_unlock(&tasklist_lock);
654 
655 	if (!stopped)
656 		return;
657 
658 	unw_init_from_blocked_task(&info, child);
659 	do_sync_rbs(&info, ia64_sync_user_rbs);
660 
661 	/*
662 	 * Now move the child back into TASK_STOPPED if it should be in a
663 	 * job control stop, so that SIGCONT can be used to wake it up.
664 	 */
665 	read_lock(&tasklist_lock);
666 	if (child->sighand) {
667 		spin_lock_irq(&child->sighand->siglock);
668 		if (child->state == TASK_TRACED &&
669 		    (child->signal->flags & SIGNAL_STOP_STOPPED)) {
670 			child->state = TASK_STOPPED;
671 		}
672 		spin_unlock_irq(&child->sighand->siglock);
673 	}
674 	read_unlock(&tasklist_lock);
675 }
676 
677 /*
678  * Write f32-f127 back to task->thread.fph if it has been modified.
679  */
680 inline void
681 ia64_flush_fph (struct task_struct *task)
682 {
683 	struct ia64_psr *psr = ia64_psr(task_pt_regs(task));
684 
685 	/*
686 	 * Prevent migrating this task while
687 	 * we're fiddling with the FPU state
688 	 */
689 	preempt_disable();
690 	if (ia64_is_local_fpu_owner(task) && psr->mfh) {
691 		psr->mfh = 0;
692 		task->thread.flags |= IA64_THREAD_FPH_VALID;
693 		ia64_save_fpu(&task->thread.fph[0]);
694 	}
695 	preempt_enable();
696 }
697 
698 /*
699  * Sync the fph state of the task so that it can be manipulated
700  * through thread.fph.  If necessary, f32-f127 are written back to
701  * thread.fph or, if the fph state hasn't been used before, thread.fph
702  * is cleared to zeroes.  Also, access to f32-f127 is disabled to
703  * ensure that the task picks up the state from thread.fph when it
704  * executes again.
705  */
706 void
707 ia64_sync_fph (struct task_struct *task)
708 {
709 	struct ia64_psr *psr = ia64_psr(task_pt_regs(task));
710 
711 	ia64_flush_fph(task);
712 	if (!(task->thread.flags & IA64_THREAD_FPH_VALID)) {
713 		task->thread.flags |= IA64_THREAD_FPH_VALID;
714 		memset(&task->thread.fph, 0, sizeof(task->thread.fph));
715 	}
716 	ia64_drop_fpu(task);
717 	psr->dfh = 1;
718 }
719 
720 /*
721  * Change the machine-state of CHILD such that it will return via the normal
722  * kernel exit-path, rather than the syscall-exit path.
723  */
724 static void
725 convert_to_non_syscall (struct task_struct *child, struct pt_regs  *pt,
726 			unsigned long cfm)
727 {
728 	struct unw_frame_info info, prev_info;
729 	unsigned long ip, sp, pr;
730 
731 	unw_init_from_blocked_task(&info, child);
732 	while (1) {
733 		prev_info = info;
734 		if (unw_unwind(&info) < 0)
735 			return;
736 
737 		unw_get_sp(&info, &sp);
738 		if ((long)((unsigned long)child + IA64_STK_OFFSET - sp)
739 		    < IA64_PT_REGS_SIZE) {
740 			dprintk("ptrace.%s: ran off the top of the kernel "
741 				"stack\n", __func__);
742 			return;
743 		}
744 		if (unw_get_pr (&prev_info, &pr) < 0) {
745 			unw_get_rp(&prev_info, &ip);
746 			dprintk("ptrace.%s: failed to read "
747 				"predicate register (ip=0x%lx)\n",
748 				__func__, ip);
749 			return;
750 		}
751 		if (unw_is_intr_frame(&info)
752 		    && (pr & (1UL << PRED_USER_STACK)))
753 			break;
754 	}
755 
756 	/*
757 	 * Note: at the time of this call, the target task is blocked
758 	 * in notify_resume_user() and by clearling PRED_LEAVE_SYSCALL
759 	 * (aka, "pLvSys") we redirect execution from
760 	 * .work_pending_syscall_end to .work_processed_kernel.
761 	 */
762 	unw_get_pr(&prev_info, &pr);
763 	pr &= ~((1UL << PRED_SYSCALL) | (1UL << PRED_LEAVE_SYSCALL));
764 	pr |=  (1UL << PRED_NON_SYSCALL);
765 	unw_set_pr(&prev_info, pr);
766 
767 	pt->cr_ifs = (1UL << 63) | cfm;
768 	/*
769 	 * Clear the memory that is NOT written on syscall-entry to
770 	 * ensure we do not leak kernel-state to user when execution
771 	 * resumes.
772 	 */
773 	pt->r2 = 0;
774 	pt->r3 = 0;
775 	pt->r14 = 0;
776 	memset(&pt->r16, 0, 16*8);	/* clear r16-r31 */
777 	memset(&pt->f6, 0, 6*16);	/* clear f6-f11 */
778 	pt->b7 = 0;
779 	pt->ar_ccv = 0;
780 	pt->ar_csd = 0;
781 	pt->ar_ssd = 0;
782 }
783 
784 static int
785 access_nat_bits (struct task_struct *child, struct pt_regs *pt,
786 		 struct unw_frame_info *info,
787 		 unsigned long *data, int write_access)
788 {
789 	unsigned long regnum, nat_bits, scratch_unat, dummy = 0;
790 	char nat = 0;
791 
792 	if (write_access) {
793 		nat_bits = *data;
794 		scratch_unat = ia64_put_scratch_nat_bits(pt, nat_bits);
795 		if (unw_set_ar(info, UNW_AR_UNAT, scratch_unat) < 0) {
796 			dprintk("ptrace: failed to set ar.unat\n");
797 			return -1;
798 		}
799 		for (regnum = 4; regnum <= 7; ++regnum) {
800 			unw_get_gr(info, regnum, &dummy, &nat);
801 			unw_set_gr(info, regnum, dummy,
802 				   (nat_bits >> regnum) & 1);
803 		}
804 	} else {
805 		if (unw_get_ar(info, UNW_AR_UNAT, &scratch_unat) < 0) {
806 			dprintk("ptrace: failed to read ar.unat\n");
807 			return -1;
808 		}
809 		nat_bits = ia64_get_scratch_nat_bits(pt, scratch_unat);
810 		for (regnum = 4; regnum <= 7; ++regnum) {
811 			unw_get_gr(info, regnum, &dummy, &nat);
812 			nat_bits |= (nat != 0) << regnum;
813 		}
814 		*data = nat_bits;
815 	}
816 	return 0;
817 }
818 
819 static int
820 access_elf_reg(struct task_struct *target, struct unw_frame_info *info,
821 		unsigned long addr, unsigned long *data, int write_access);
822 
823 static long
824 ptrace_getregs (struct task_struct *child, struct pt_all_user_regs __user *ppr)
825 {
826 	unsigned long psr, ec, lc, rnat, bsp, cfm, nat_bits, val;
827 	struct unw_frame_info info;
828 	struct ia64_fpreg fpval;
829 	struct switch_stack *sw;
830 	struct pt_regs *pt;
831 	long ret, retval = 0;
832 	char nat = 0;
833 	int i;
834 
835 	if (!access_ok(ppr, sizeof(struct pt_all_user_regs)))
836 		return -EIO;
837 
838 	pt = task_pt_regs(child);
839 	sw = (struct switch_stack *) (child->thread.ksp + 16);
840 	unw_init_from_blocked_task(&info, child);
841 	if (unw_unwind_to_user(&info) < 0) {
842 		return -EIO;
843 	}
844 
845 	if (((unsigned long) ppr & 0x7) != 0) {
846 		dprintk("ptrace:unaligned register address %p\n", ppr);
847 		return -EIO;
848 	}
849 
850 	if (access_elf_reg(child, &info, ELF_CR_IPSR_OFFSET, &psr, 0) < 0 ||
851 	    access_elf_reg(child, &info, ELF_AR_EC_OFFSET, &ec, 0) < 0 ||
852 	    access_elf_reg(child, &info, ELF_AR_LC_OFFSET, &lc, 0) < 0 ||
853 	    access_elf_reg(child, &info, ELF_AR_RNAT_OFFSET, &rnat, 0) < 0 ||
854 	    access_elf_reg(child, &info, ELF_AR_BSP_OFFSET, &bsp, 0) < 0 ||
855 	    access_elf_reg(child, &info, ELF_CFM_OFFSET, &cfm, 0) < 0 ||
856 	    access_elf_reg(child, &info, ELF_NAT_OFFSET, &nat_bits, 0) < 0)
857 		return -EIO;
858 
859 	/* control regs */
860 
861 	retval |= __put_user(pt->cr_iip, &ppr->cr_iip);
862 	retval |= __put_user(psr, &ppr->cr_ipsr);
863 
864 	/* app regs */
865 
866 	retval |= __put_user(pt->ar_pfs, &ppr->ar[PT_AUR_PFS]);
867 	retval |= __put_user(pt->ar_rsc, &ppr->ar[PT_AUR_RSC]);
868 	retval |= __put_user(pt->ar_bspstore, &ppr->ar[PT_AUR_BSPSTORE]);
869 	retval |= __put_user(pt->ar_unat, &ppr->ar[PT_AUR_UNAT]);
870 	retval |= __put_user(pt->ar_ccv, &ppr->ar[PT_AUR_CCV]);
871 	retval |= __put_user(pt->ar_fpsr, &ppr->ar[PT_AUR_FPSR]);
872 
873 	retval |= __put_user(ec, &ppr->ar[PT_AUR_EC]);
874 	retval |= __put_user(lc, &ppr->ar[PT_AUR_LC]);
875 	retval |= __put_user(rnat, &ppr->ar[PT_AUR_RNAT]);
876 	retval |= __put_user(bsp, &ppr->ar[PT_AUR_BSP]);
877 	retval |= __put_user(cfm, &ppr->cfm);
878 
879 	/* gr1-gr3 */
880 
881 	retval |= __copy_to_user(&ppr->gr[1], &pt->r1, sizeof(long));
882 	retval |= __copy_to_user(&ppr->gr[2], &pt->r2, sizeof(long) *2);
883 
884 	/* gr4-gr7 */
885 
886 	for (i = 4; i < 8; i++) {
887 		if (unw_access_gr(&info, i, &val, &nat, 0) < 0)
888 			return -EIO;
889 		retval |= __put_user(val, &ppr->gr[i]);
890 	}
891 
892 	/* gr8-gr11 */
893 
894 	retval |= __copy_to_user(&ppr->gr[8], &pt->r8, sizeof(long) * 4);
895 
896 	/* gr12-gr15 */
897 
898 	retval |= __copy_to_user(&ppr->gr[12], &pt->r12, sizeof(long) * 2);
899 	retval |= __copy_to_user(&ppr->gr[14], &pt->r14, sizeof(long));
900 	retval |= __copy_to_user(&ppr->gr[15], &pt->r15, sizeof(long));
901 
902 	/* gr16-gr31 */
903 
904 	retval |= __copy_to_user(&ppr->gr[16], &pt->r16, sizeof(long) * 16);
905 
906 	/* b0 */
907 
908 	retval |= __put_user(pt->b0, &ppr->br[0]);
909 
910 	/* b1-b5 */
911 
912 	for (i = 1; i < 6; i++) {
913 		if (unw_access_br(&info, i, &val, 0) < 0)
914 			return -EIO;
915 		__put_user(val, &ppr->br[i]);
916 	}
917 
918 	/* b6-b7 */
919 
920 	retval |= __put_user(pt->b6, &ppr->br[6]);
921 	retval |= __put_user(pt->b7, &ppr->br[7]);
922 
923 	/* fr2-fr5 */
924 
925 	for (i = 2; i < 6; i++) {
926 		if (unw_get_fr(&info, i, &fpval) < 0)
927 			return -EIO;
928 		retval |= __copy_to_user(&ppr->fr[i], &fpval, sizeof (fpval));
929 	}
930 
931 	/* fr6-fr11 */
932 
933 	retval |= __copy_to_user(&ppr->fr[6], &pt->f6,
934 				 sizeof(struct ia64_fpreg) * 6);
935 
936 	/* fp scratch regs(12-15) */
937 
938 	retval |= __copy_to_user(&ppr->fr[12], &sw->f12,
939 				 sizeof(struct ia64_fpreg) * 4);
940 
941 	/* fr16-fr31 */
942 
943 	for (i = 16; i < 32; i++) {
944 		if (unw_get_fr(&info, i, &fpval) < 0)
945 			return -EIO;
946 		retval |= __copy_to_user(&ppr->fr[i], &fpval, sizeof (fpval));
947 	}
948 
949 	/* fph */
950 
951 	ia64_flush_fph(child);
952 	retval |= __copy_to_user(&ppr->fr[32], &child->thread.fph,
953 				 sizeof(ppr->fr[32]) * 96);
954 
955 	/*  preds */
956 
957 	retval |= __put_user(pt->pr, &ppr->pr);
958 
959 	/* nat bits */
960 
961 	retval |= __put_user(nat_bits, &ppr->nat);
962 
963 	ret = retval ? -EIO : 0;
964 	return ret;
965 }
966 
967 static long
968 ptrace_setregs (struct task_struct *child, struct pt_all_user_regs __user *ppr)
969 {
970 	unsigned long psr, rsc, ec, lc, rnat, bsp, cfm, nat_bits, val = 0;
971 	struct unw_frame_info info;
972 	struct switch_stack *sw;
973 	struct ia64_fpreg fpval;
974 	struct pt_regs *pt;
975 	long retval = 0;
976 	int i;
977 
978 	memset(&fpval, 0, sizeof(fpval));
979 
980 	if (!access_ok(ppr, sizeof(struct pt_all_user_regs)))
981 		return -EIO;
982 
983 	pt = task_pt_regs(child);
984 	sw = (struct switch_stack *) (child->thread.ksp + 16);
985 	unw_init_from_blocked_task(&info, child);
986 	if (unw_unwind_to_user(&info) < 0) {
987 		return -EIO;
988 	}
989 
990 	if (((unsigned long) ppr & 0x7) != 0) {
991 		dprintk("ptrace:unaligned register address %p\n", ppr);
992 		return -EIO;
993 	}
994 
995 	/* control regs */
996 
997 	retval |= __get_user(pt->cr_iip, &ppr->cr_iip);
998 	retval |= __get_user(psr, &ppr->cr_ipsr);
999 
1000 	/* app regs */
1001 
1002 	retval |= __get_user(pt->ar_pfs, &ppr->ar[PT_AUR_PFS]);
1003 	retval |= __get_user(rsc, &ppr->ar[PT_AUR_RSC]);
1004 	retval |= __get_user(pt->ar_bspstore, &ppr->ar[PT_AUR_BSPSTORE]);
1005 	retval |= __get_user(pt->ar_unat, &ppr->ar[PT_AUR_UNAT]);
1006 	retval |= __get_user(pt->ar_ccv, &ppr->ar[PT_AUR_CCV]);
1007 	retval |= __get_user(pt->ar_fpsr, &ppr->ar[PT_AUR_FPSR]);
1008 
1009 	retval |= __get_user(ec, &ppr->ar[PT_AUR_EC]);
1010 	retval |= __get_user(lc, &ppr->ar[PT_AUR_LC]);
1011 	retval |= __get_user(rnat, &ppr->ar[PT_AUR_RNAT]);
1012 	retval |= __get_user(bsp, &ppr->ar[PT_AUR_BSP]);
1013 	retval |= __get_user(cfm, &ppr->cfm);
1014 
1015 	/* gr1-gr3 */
1016 
1017 	retval |= __copy_from_user(&pt->r1, &ppr->gr[1], sizeof(long));
1018 	retval |= __copy_from_user(&pt->r2, &ppr->gr[2], sizeof(long) * 2);
1019 
1020 	/* gr4-gr7 */
1021 
1022 	for (i = 4; i < 8; i++) {
1023 		retval |= __get_user(val, &ppr->gr[i]);
1024 		/* NaT bit will be set via PT_NAT_BITS: */
1025 		if (unw_set_gr(&info, i, val, 0) < 0)
1026 			return -EIO;
1027 	}
1028 
1029 	/* gr8-gr11 */
1030 
1031 	retval |= __copy_from_user(&pt->r8, &ppr->gr[8], sizeof(long) * 4);
1032 
1033 	/* gr12-gr15 */
1034 
1035 	retval |= __copy_from_user(&pt->r12, &ppr->gr[12], sizeof(long) * 2);
1036 	retval |= __copy_from_user(&pt->r14, &ppr->gr[14], sizeof(long));
1037 	retval |= __copy_from_user(&pt->r15, &ppr->gr[15], sizeof(long));
1038 
1039 	/* gr16-gr31 */
1040 
1041 	retval |= __copy_from_user(&pt->r16, &ppr->gr[16], sizeof(long) * 16);
1042 
1043 	/* b0 */
1044 
1045 	retval |= __get_user(pt->b0, &ppr->br[0]);
1046 
1047 	/* b1-b5 */
1048 
1049 	for (i = 1; i < 6; i++) {
1050 		retval |= __get_user(val, &ppr->br[i]);
1051 		unw_set_br(&info, i, val);
1052 	}
1053 
1054 	/* b6-b7 */
1055 
1056 	retval |= __get_user(pt->b6, &ppr->br[6]);
1057 	retval |= __get_user(pt->b7, &ppr->br[7]);
1058 
1059 	/* fr2-fr5 */
1060 
1061 	for (i = 2; i < 6; i++) {
1062 		retval |= __copy_from_user(&fpval, &ppr->fr[i], sizeof(fpval));
1063 		if (unw_set_fr(&info, i, fpval) < 0)
1064 			return -EIO;
1065 	}
1066 
1067 	/* fr6-fr11 */
1068 
1069 	retval |= __copy_from_user(&pt->f6, &ppr->fr[6],
1070 				   sizeof(ppr->fr[6]) * 6);
1071 
1072 	/* fp scratch regs(12-15) */
1073 
1074 	retval |= __copy_from_user(&sw->f12, &ppr->fr[12],
1075 				   sizeof(ppr->fr[12]) * 4);
1076 
1077 	/* fr16-fr31 */
1078 
1079 	for (i = 16; i < 32; i++) {
1080 		retval |= __copy_from_user(&fpval, &ppr->fr[i],
1081 					   sizeof(fpval));
1082 		if (unw_set_fr(&info, i, fpval) < 0)
1083 			return -EIO;
1084 	}
1085 
1086 	/* fph */
1087 
1088 	ia64_sync_fph(child);
1089 	retval |= __copy_from_user(&child->thread.fph, &ppr->fr[32],
1090 				   sizeof(ppr->fr[32]) * 96);
1091 
1092 	/* preds */
1093 
1094 	retval |= __get_user(pt->pr, &ppr->pr);
1095 
1096 	/* nat bits */
1097 
1098 	retval |= __get_user(nat_bits, &ppr->nat);
1099 
1100 	retval |= access_elf_reg(child, &info, ELF_CR_IPSR_OFFSET, &psr, 1);
1101 	retval |= access_elf_reg(child, &info, ELF_AR_RSC_OFFSET, &rsc, 1);
1102 	retval |= access_elf_reg(child, &info, ELF_AR_EC_OFFSET, &ec, 1);
1103 	retval |= access_elf_reg(child, &info, ELF_AR_LC_OFFSET, &lc, 1);
1104 	retval |= access_elf_reg(child, &info, ELF_AR_RNAT_OFFSET, &rnat, 1);
1105 	retval |= access_elf_reg(child, &info, ELF_AR_BSP_OFFSET, &bsp, 1);
1106 	retval |= access_elf_reg(child, &info, ELF_CFM_OFFSET, &cfm, 1);
1107 	retval |= access_elf_reg(child, &info, ELF_NAT_OFFSET, &nat_bits, 1);
1108 
1109 	return retval ? -EIO : 0;
1110 }
1111 
1112 void
1113 user_enable_single_step (struct task_struct *child)
1114 {
1115 	struct ia64_psr *child_psr = ia64_psr(task_pt_regs(child));
1116 
1117 	set_tsk_thread_flag(child, TIF_SINGLESTEP);
1118 	child_psr->ss = 1;
1119 }
1120 
1121 void
1122 user_enable_block_step (struct task_struct *child)
1123 {
1124 	struct ia64_psr *child_psr = ia64_psr(task_pt_regs(child));
1125 
1126 	set_tsk_thread_flag(child, TIF_SINGLESTEP);
1127 	child_psr->tb = 1;
1128 }
1129 
1130 void
1131 user_disable_single_step (struct task_struct *child)
1132 {
1133 	struct ia64_psr *child_psr = ia64_psr(task_pt_regs(child));
1134 
1135 	/* make sure the single step/taken-branch trap bits are not set: */
1136 	clear_tsk_thread_flag(child, TIF_SINGLESTEP);
1137 	child_psr->ss = 0;
1138 	child_psr->tb = 0;
1139 }
1140 
1141 /*
1142  * Called by kernel/ptrace.c when detaching..
1143  *
1144  * Make sure the single step bit is not set.
1145  */
1146 void
1147 ptrace_disable (struct task_struct *child)
1148 {
1149 	user_disable_single_step(child);
1150 }
1151 
1152 static int
1153 access_uarea (struct task_struct *child, unsigned long addr,
1154 	      unsigned long *data, int write_access);
1155 
1156 long
1157 arch_ptrace (struct task_struct *child, long request,
1158 	     unsigned long addr, unsigned long data)
1159 {
1160 	switch (request) {
1161 	case PTRACE_PEEKTEXT:
1162 	case PTRACE_PEEKDATA:
1163 		/* read word at location addr */
1164 		if (ptrace_access_vm(child, addr, &data, sizeof(data),
1165 				FOLL_FORCE)
1166 		    != sizeof(data))
1167 			return -EIO;
1168 		/* ensure return value is not mistaken for error code */
1169 		force_successful_syscall_return();
1170 		return data;
1171 
1172 	/* PTRACE_POKETEXT and PTRACE_POKEDATA is handled
1173 	 * by the generic ptrace_request().
1174 	 */
1175 
1176 	case PTRACE_PEEKUSR:
1177 		/* read the word at addr in the USER area */
1178 		if (access_uarea(child, addr, &data, 0) < 0)
1179 			return -EIO;
1180 		/* ensure return value is not mistaken for error code */
1181 		force_successful_syscall_return();
1182 		return data;
1183 
1184 	case PTRACE_POKEUSR:
1185 		/* write the word at addr in the USER area */
1186 		if (access_uarea(child, addr, &data, 1) < 0)
1187 			return -EIO;
1188 		return 0;
1189 
1190 	case PTRACE_OLD_GETSIGINFO:
1191 		/* for backwards-compatibility */
1192 		return ptrace_request(child, PTRACE_GETSIGINFO, addr, data);
1193 
1194 	case PTRACE_OLD_SETSIGINFO:
1195 		/* for backwards-compatibility */
1196 		return ptrace_request(child, PTRACE_SETSIGINFO, addr, data);
1197 
1198 	case PTRACE_GETREGS:
1199 		return ptrace_getregs(child,
1200 				      (struct pt_all_user_regs __user *) data);
1201 
1202 	case PTRACE_SETREGS:
1203 		return ptrace_setregs(child,
1204 				      (struct pt_all_user_regs __user *) data);
1205 
1206 	default:
1207 		return ptrace_request(child, request, addr, data);
1208 	}
1209 }
1210 
1211 
1212 /* "asmlinkage" so the input arguments are preserved... */
1213 
1214 asmlinkage long
1215 syscall_trace_enter (long arg0, long arg1, long arg2, long arg3,
1216 		     long arg4, long arg5, long arg6, long arg7,
1217 		     struct pt_regs regs)
1218 {
1219 	if (test_thread_flag(TIF_SYSCALL_TRACE))
1220 		if (tracehook_report_syscall_entry(&regs))
1221 			return -ENOSYS;
1222 
1223 	/* copy user rbs to kernel rbs */
1224 	if (test_thread_flag(TIF_RESTORE_RSE))
1225 		ia64_sync_krbs();
1226 
1227 
1228 	audit_syscall_entry(regs.r15, arg0, arg1, arg2, arg3);
1229 
1230 	return 0;
1231 }
1232 
1233 /* "asmlinkage" so the input arguments are preserved... */
1234 
1235 asmlinkage void
1236 syscall_trace_leave (long arg0, long arg1, long arg2, long arg3,
1237 		     long arg4, long arg5, long arg6, long arg7,
1238 		     struct pt_regs regs)
1239 {
1240 	int step;
1241 
1242 	audit_syscall_exit(&regs);
1243 
1244 	step = test_thread_flag(TIF_SINGLESTEP);
1245 	if (step || test_thread_flag(TIF_SYSCALL_TRACE))
1246 		tracehook_report_syscall_exit(&regs, step);
1247 
1248 	/* copy user rbs to kernel rbs */
1249 	if (test_thread_flag(TIF_RESTORE_RSE))
1250 		ia64_sync_krbs();
1251 }
1252 
1253 /* Utrace implementation starts here */
1254 struct regset_get {
1255 	void *kbuf;
1256 	void __user *ubuf;
1257 };
1258 
1259 struct regset_set {
1260 	const void *kbuf;
1261 	const void __user *ubuf;
1262 };
1263 
1264 struct regset_getset {
1265 	struct task_struct *target;
1266 	const struct user_regset *regset;
1267 	union {
1268 		struct regset_get get;
1269 		struct regset_set set;
1270 	} u;
1271 	unsigned int pos;
1272 	unsigned int count;
1273 	int ret;
1274 };
1275 
1276 static const ptrdiff_t pt_offsets[32] =
1277 {
1278 #define R(n) offsetof(struct pt_regs, r##n)
1279 	[0] = -1, R(1), R(2), R(3),
1280 	[4] = -1, [5] = -1, [6] = -1, [7] = -1,
1281 	R(8), R(9), R(10), R(11), R(12), R(13), R(14), R(15),
1282 	R(16), R(17), R(18), R(19), R(20), R(21), R(22), R(23),
1283 	R(24), R(25), R(26), R(27), R(28), R(29), R(30), R(31),
1284 #undef R
1285 };
1286 
1287 static int
1288 access_elf_gpreg(struct task_struct *target, struct unw_frame_info *info,
1289 		unsigned long addr, unsigned long *data, int write_access)
1290 {
1291 	struct pt_regs *pt = task_pt_regs(target);
1292 	unsigned reg = addr / sizeof(unsigned long);
1293 	ptrdiff_t d = pt_offsets[reg];
1294 
1295 	if (d >= 0) {
1296 		unsigned long *ptr = (void *)pt + d;
1297 		if (write_access)
1298 			*ptr = *data;
1299 		else
1300 			*data = *ptr;
1301 		return 0;
1302 	} else {
1303 		char nat = 0;
1304 		if (write_access) {
1305 			/* read NaT bit first: */
1306 			unsigned long dummy;
1307 			int ret = unw_get_gr(info, reg, &dummy, &nat);
1308 			if (ret < 0)
1309 				return ret;
1310 		}
1311 		return unw_access_gr(info, reg, data, &nat, write_access);
1312 	}
1313 }
1314 
1315 static int
1316 access_elf_breg(struct task_struct *target, struct unw_frame_info *info,
1317 		unsigned long addr, unsigned long *data, int write_access)
1318 {
1319 	struct pt_regs *pt;
1320 	unsigned long *ptr = NULL;
1321 
1322 	pt = task_pt_regs(target);
1323 	switch (addr) {
1324 	case ELF_BR_OFFSET(0):
1325 		ptr = &pt->b0;
1326 		break;
1327 	case ELF_BR_OFFSET(1) ... ELF_BR_OFFSET(5):
1328 		return unw_access_br(info, (addr - ELF_BR_OFFSET(0))/8,
1329 				     data, write_access);
1330 	case ELF_BR_OFFSET(6):
1331 		ptr = &pt->b6;
1332 		break;
1333 	case ELF_BR_OFFSET(7):
1334 		ptr = &pt->b7;
1335 	}
1336 	if (write_access)
1337 		*ptr = *data;
1338 	else
1339 		*data = *ptr;
1340 	return 0;
1341 }
1342 
1343 static int
1344 access_elf_areg(struct task_struct *target, struct unw_frame_info *info,
1345 		unsigned long addr, unsigned long *data, int write_access)
1346 {
1347 	struct pt_regs *pt;
1348 	unsigned long cfm, urbs_end;
1349 	unsigned long *ptr = NULL;
1350 
1351 	pt = task_pt_regs(target);
1352 	if (addr >= ELF_AR_RSC_OFFSET && addr <= ELF_AR_SSD_OFFSET) {
1353 		switch (addr) {
1354 		case ELF_AR_RSC_OFFSET:
1355 			/* force PL3 */
1356 			if (write_access)
1357 				pt->ar_rsc = *data | (3 << 2);
1358 			else
1359 				*data = pt->ar_rsc;
1360 			return 0;
1361 		case ELF_AR_BSP_OFFSET:
1362 			/*
1363 			 * By convention, we use PT_AR_BSP to refer to
1364 			 * the end of the user-level backing store.
1365 			 * Use ia64_rse_skip_regs(PT_AR_BSP, -CFM.sof)
1366 			 * to get the real value of ar.bsp at the time
1367 			 * the kernel was entered.
1368 			 *
1369 			 * Furthermore, when changing the contents of
1370 			 * PT_AR_BSP (or PT_CFM) while the task is
1371 			 * blocked in a system call, convert the state
1372 			 * so that the non-system-call exit
1373 			 * path is used.  This ensures that the proper
1374 			 * state will be picked up when resuming
1375 			 * execution.  However, it *also* means that
1376 			 * once we write PT_AR_BSP/PT_CFM, it won't be
1377 			 * possible to modify the syscall arguments of
1378 			 * the pending system call any longer.  This
1379 			 * shouldn't be an issue because modifying
1380 			 * PT_AR_BSP/PT_CFM generally implies that
1381 			 * we're either abandoning the pending system
1382 			 * call or that we defer it's re-execution
1383 			 * (e.g., due to GDB doing an inferior
1384 			 * function call).
1385 			 */
1386 			urbs_end = ia64_get_user_rbs_end(target, pt, &cfm);
1387 			if (write_access) {
1388 				if (*data != urbs_end) {
1389 					if (in_syscall(pt))
1390 						convert_to_non_syscall(target,
1391 								       pt,
1392 								       cfm);
1393 					/*
1394 					 * Simulate user-level write
1395 					 * of ar.bsp:
1396 					 */
1397 					pt->loadrs = 0;
1398 					pt->ar_bspstore = *data;
1399 				}
1400 			} else
1401 				*data = urbs_end;
1402 			return 0;
1403 		case ELF_AR_BSPSTORE_OFFSET:
1404 			ptr = &pt->ar_bspstore;
1405 			break;
1406 		case ELF_AR_RNAT_OFFSET:
1407 			ptr = &pt->ar_rnat;
1408 			break;
1409 		case ELF_AR_CCV_OFFSET:
1410 			ptr = &pt->ar_ccv;
1411 			break;
1412 		case ELF_AR_UNAT_OFFSET:
1413 			ptr = &pt->ar_unat;
1414 			break;
1415 		case ELF_AR_FPSR_OFFSET:
1416 			ptr = &pt->ar_fpsr;
1417 			break;
1418 		case ELF_AR_PFS_OFFSET:
1419 			ptr = &pt->ar_pfs;
1420 			break;
1421 		case ELF_AR_LC_OFFSET:
1422 			return unw_access_ar(info, UNW_AR_LC, data,
1423 					     write_access);
1424 		case ELF_AR_EC_OFFSET:
1425 			return unw_access_ar(info, UNW_AR_EC, data,
1426 					     write_access);
1427 		case ELF_AR_CSD_OFFSET:
1428 			ptr = &pt->ar_csd;
1429 			break;
1430 		case ELF_AR_SSD_OFFSET:
1431 			ptr = &pt->ar_ssd;
1432 		}
1433 	} else if (addr >= ELF_CR_IIP_OFFSET && addr <= ELF_CR_IPSR_OFFSET) {
1434 		switch (addr) {
1435 		case ELF_CR_IIP_OFFSET:
1436 			ptr = &pt->cr_iip;
1437 			break;
1438 		case ELF_CFM_OFFSET:
1439 			urbs_end = ia64_get_user_rbs_end(target, pt, &cfm);
1440 			if (write_access) {
1441 				if (((cfm ^ *data) & PFM_MASK) != 0) {
1442 					if (in_syscall(pt))
1443 						convert_to_non_syscall(target,
1444 								       pt,
1445 								       cfm);
1446 					pt->cr_ifs = ((pt->cr_ifs & ~PFM_MASK)
1447 						      | (*data & PFM_MASK));
1448 				}
1449 			} else
1450 				*data = cfm;
1451 			return 0;
1452 		case ELF_CR_IPSR_OFFSET:
1453 			if (write_access) {
1454 				unsigned long tmp = *data;
1455 				/* psr.ri==3 is a reserved value: SDM 2:25 */
1456 				if ((tmp & IA64_PSR_RI) == IA64_PSR_RI)
1457 					tmp &= ~IA64_PSR_RI;
1458 				pt->cr_ipsr = ((tmp & IPSR_MASK)
1459 					       | (pt->cr_ipsr & ~IPSR_MASK));
1460 			} else
1461 				*data = (pt->cr_ipsr & IPSR_MASK);
1462 			return 0;
1463 		}
1464 	} else if (addr == ELF_NAT_OFFSET)
1465 		return access_nat_bits(target, pt, info,
1466 				       data, write_access);
1467 	else if (addr == ELF_PR_OFFSET)
1468 		ptr = &pt->pr;
1469 	else
1470 		return -1;
1471 
1472 	if (write_access)
1473 		*ptr = *data;
1474 	else
1475 		*data = *ptr;
1476 
1477 	return 0;
1478 }
1479 
1480 static int
1481 access_elf_reg(struct task_struct *target, struct unw_frame_info *info,
1482 		unsigned long addr, unsigned long *data, int write_access)
1483 {
1484 	if (addr >= ELF_GR_OFFSET(1) && addr <= ELF_GR_OFFSET(31))
1485 		return access_elf_gpreg(target, info, addr, data, write_access);
1486 	else if (addr >= ELF_BR_OFFSET(0) && addr <= ELF_BR_OFFSET(7))
1487 		return access_elf_breg(target, info, addr, data, write_access);
1488 	else
1489 		return access_elf_areg(target, info, addr, data, write_access);
1490 }
1491 
1492 struct regset_membuf {
1493 	struct membuf to;
1494 	int ret;
1495 };
1496 
1497 static void do_gpregs_get(struct unw_frame_info *info, void *arg)
1498 {
1499 	struct regset_membuf *dst = arg;
1500 	struct membuf to = dst->to;
1501 	unsigned int n;
1502 	elf_greg_t reg;
1503 
1504 	if (unw_unwind_to_user(info) < 0)
1505 		return;
1506 
1507 	/*
1508 	 * coredump format:
1509 	 *      r0-r31
1510 	 *      NaT bits (for r0-r31; bit N == 1 iff rN is a NaT)
1511 	 *      predicate registers (p0-p63)
1512 	 *      b0-b7
1513 	 *      ip cfm user-mask
1514 	 *      ar.rsc ar.bsp ar.bspstore ar.rnat
1515 	 *      ar.ccv ar.unat ar.fpsr ar.pfs ar.lc ar.ec
1516 	 */
1517 
1518 
1519 	/* Skip r0 */
1520 	membuf_zero(&to, 8);
1521 	for (n = 8; to.left && n < ELF_AR_END_OFFSET; n += 8) {
1522 		if (access_elf_reg(info->task, info, n, &reg, 0) < 0) {
1523 			dst->ret = -EIO;
1524 			return;
1525 		}
1526 		membuf_store(&to, reg);
1527 	}
1528 }
1529 
1530 static void do_gpregs_set(struct unw_frame_info *info, void *arg)
1531 {
1532 	struct regset_getset *dst = arg;
1533 
1534 	if (unw_unwind_to_user(info) < 0)
1535 		return;
1536 
1537 	if (!dst->count)
1538 		return;
1539 	/* Skip r0 */
1540 	if (dst->pos < ELF_GR_OFFSET(1)) {
1541 		dst->ret = user_regset_copyin_ignore(&dst->pos, &dst->count,
1542 						       &dst->u.set.kbuf,
1543 						       &dst->u.set.ubuf,
1544 						       0, ELF_GR_OFFSET(1));
1545 		if (dst->ret)
1546 			return;
1547 	}
1548 
1549 	while (dst->count && dst->pos < ELF_AR_END_OFFSET) {
1550 		unsigned int n, from, to;
1551 		elf_greg_t tmp[16];
1552 
1553 		from = dst->pos;
1554 		to = from + sizeof(tmp);
1555 		if (to > ELF_AR_END_OFFSET)
1556 			to = ELF_AR_END_OFFSET;
1557 		/* get up to 16 values */
1558 		dst->ret = user_regset_copyin(&dst->pos, &dst->count,
1559 				&dst->u.set.kbuf, &dst->u.set.ubuf, tmp,
1560 				from, to);
1561 		if (dst->ret)
1562 			return;
1563 		/* now copy them into registers */
1564 		for (n = 0; from < dst->pos; from += sizeof(elf_greg_t), n++)
1565 			if (access_elf_reg(dst->target, info, from,
1566 						&tmp[n], 1) < 0) {
1567 				dst->ret = -EIO;
1568 				return;
1569 			}
1570 	}
1571 }
1572 
1573 #define ELF_FP_OFFSET(i)	(i * sizeof(elf_fpreg_t))
1574 
1575 static void do_fpregs_get(struct unw_frame_info *info, void *arg)
1576 {
1577 	struct task_struct *task = info->task;
1578 	struct regset_membuf *dst = arg;
1579 	struct membuf to = dst->to;
1580 	elf_fpreg_t reg;
1581 	unsigned int n;
1582 
1583 	if (unw_unwind_to_user(info) < 0)
1584 		return;
1585 
1586 	/* Skip pos 0 and 1 */
1587 	membuf_zero(&to, 2 * sizeof(elf_fpreg_t));
1588 
1589 	/* fr2-fr31 */
1590 	for (n = 2; to.left && n < 32; n++) {
1591 		if (unw_get_fr(info, n, &reg)) {
1592 			dst->ret = -EIO;
1593 			return;
1594 		}
1595 		membuf_write(&to, &reg, sizeof(reg));
1596 	}
1597 
1598 	/* fph */
1599 	if (!to.left)
1600 		return;
1601 
1602 	ia64_flush_fph(task);
1603 	if (task->thread.flags & IA64_THREAD_FPH_VALID)
1604 		membuf_write(&to, &task->thread.fph, 96 * sizeof(reg));
1605 	else
1606 		membuf_zero(&to, 96 * sizeof(reg));
1607 }
1608 
1609 static void do_fpregs_set(struct unw_frame_info *info, void *arg)
1610 {
1611 	struct regset_getset *dst = arg;
1612 	elf_fpreg_t fpreg, tmp[30];
1613 	int index, start, end;
1614 
1615 	if (unw_unwind_to_user(info) < 0)
1616 		return;
1617 
1618 	/* Skip pos 0 and 1 */
1619 	if (dst->count > 0 && dst->pos < ELF_FP_OFFSET(2)) {
1620 		dst->ret = user_regset_copyin_ignore(&dst->pos, &dst->count,
1621 						       &dst->u.set.kbuf,
1622 						       &dst->u.set.ubuf,
1623 						       0, ELF_FP_OFFSET(2));
1624 		if (dst->count == 0 || dst->ret)
1625 			return;
1626 	}
1627 
1628 	/* fr2-fr31 */
1629 	if (dst->count > 0 && dst->pos < ELF_FP_OFFSET(32)) {
1630 		start = dst->pos;
1631 		end = min(((unsigned int)ELF_FP_OFFSET(32)),
1632 			 dst->pos + dst->count);
1633 		dst->ret = user_regset_copyin(&dst->pos, &dst->count,
1634 				&dst->u.set.kbuf, &dst->u.set.ubuf, tmp,
1635 				ELF_FP_OFFSET(2), ELF_FP_OFFSET(32));
1636 		if (dst->ret)
1637 			return;
1638 
1639 		if (start & 0xF) { /* only write high part */
1640 			if (unw_get_fr(info, start / sizeof(elf_fpreg_t),
1641 					 &fpreg)) {
1642 				dst->ret = -EIO;
1643 				return;
1644 			}
1645 			tmp[start / sizeof(elf_fpreg_t) - 2].u.bits[0]
1646 				= fpreg.u.bits[0];
1647 			start &= ~0xFUL;
1648 		}
1649 		if (end & 0xF) { /* only write low part */
1650 			if (unw_get_fr(info, end / sizeof(elf_fpreg_t),
1651 					&fpreg)) {
1652 				dst->ret = -EIO;
1653 				return;
1654 			}
1655 			tmp[end / sizeof(elf_fpreg_t) - 2].u.bits[1]
1656 				= fpreg.u.bits[1];
1657 			end = (end + 0xF) & ~0xFUL;
1658 		}
1659 
1660 		for ( ;	start < end ; start += sizeof(elf_fpreg_t)) {
1661 			index = start / sizeof(elf_fpreg_t);
1662 			if (unw_set_fr(info, index, tmp[index - 2])) {
1663 				dst->ret = -EIO;
1664 				return;
1665 			}
1666 		}
1667 		if (dst->ret || dst->count == 0)
1668 			return;
1669 	}
1670 
1671 	/* fph */
1672 	if (dst->count > 0 && dst->pos < ELF_FP_OFFSET(128)) {
1673 		ia64_sync_fph(dst->target);
1674 		dst->ret = user_regset_copyin(&dst->pos, &dst->count,
1675 						&dst->u.set.kbuf,
1676 						&dst->u.set.ubuf,
1677 						&dst->target->thread.fph,
1678 						ELF_FP_OFFSET(32), -1);
1679 	}
1680 }
1681 
1682 static void
1683 unwind_and_call(void (*call)(struct unw_frame_info *, void *),
1684 	       struct task_struct *target, void *data)
1685 {
1686 	if (target == current)
1687 		unw_init_running(call, data);
1688 	else {
1689 		struct unw_frame_info info;
1690 		memset(&info, 0, sizeof(info));
1691 		unw_init_from_blocked_task(&info, target);
1692 		(*call)(&info, data);
1693 	}
1694 }
1695 
1696 static int
1697 do_regset_call(void (*call)(struct unw_frame_info *, void *),
1698 	       struct task_struct *target,
1699 	       const struct user_regset *regset,
1700 	       unsigned int pos, unsigned int count,
1701 	       const void *kbuf, const void __user *ubuf)
1702 {
1703 	struct regset_getset info = { .target = target, .regset = regset,
1704 				 .pos = pos, .count = count,
1705 				 .u.set = { .kbuf = kbuf, .ubuf = ubuf },
1706 				 .ret = 0 };
1707 	unwind_and_call(call, target, &info);
1708 	return info.ret;
1709 }
1710 
1711 static int
1712 gpregs_get(struct task_struct *target,
1713 	   const struct user_regset *regset,
1714 	   struct membuf to)
1715 {
1716 	struct regset_membuf info = {.to = to};
1717 	unwind_and_call(do_gpregs_get, target, &info);
1718 	return info.ret;
1719 }
1720 
1721 static int gpregs_set(struct task_struct *target,
1722 		const struct user_regset *regset,
1723 		unsigned int pos, unsigned int count,
1724 		const void *kbuf, const void __user *ubuf)
1725 {
1726 	return do_regset_call(do_gpregs_set, target, regset, pos, count,
1727 		kbuf, ubuf);
1728 }
1729 
1730 static void do_gpregs_writeback(struct unw_frame_info *info, void *arg)
1731 {
1732 	do_sync_rbs(info, ia64_sync_user_rbs);
1733 }
1734 
1735 /*
1736  * This is called to write back the register backing store.
1737  * ptrace does this before it stops, so that a tracer reading the user
1738  * memory after the thread stops will get the current register data.
1739  */
1740 static int
1741 gpregs_writeback(struct task_struct *target,
1742 		 const struct user_regset *regset,
1743 		 int now)
1744 {
1745 	if (test_and_set_tsk_thread_flag(target, TIF_RESTORE_RSE))
1746 		return 0;
1747 	set_notify_resume(target);
1748 	return do_regset_call(do_gpregs_writeback, target, regset, 0, 0,
1749 		NULL, NULL);
1750 }
1751 
1752 static int
1753 fpregs_active(struct task_struct *target, const struct user_regset *regset)
1754 {
1755 	return (target->thread.flags & IA64_THREAD_FPH_VALID) ? 128 : 32;
1756 }
1757 
1758 static int fpregs_get(struct task_struct *target,
1759 		const struct user_regset *regset,
1760 		struct membuf to)
1761 {
1762 	struct regset_membuf info = {.to = to};
1763 	unwind_and_call(do_fpregs_get, target, &info);
1764 	return info.ret;
1765 }
1766 
1767 static int fpregs_set(struct task_struct *target,
1768 		const struct user_regset *regset,
1769 		unsigned int pos, unsigned int count,
1770 		const void *kbuf, const void __user *ubuf)
1771 {
1772 	return do_regset_call(do_fpregs_set, target, regset, pos, count,
1773 		kbuf, ubuf);
1774 }
1775 
1776 static int
1777 access_uarea(struct task_struct *child, unsigned long addr,
1778 	      unsigned long *data, int write_access)
1779 {
1780 	unsigned int pos = -1; /* an invalid value */
1781 	unsigned long *ptr, regnum;
1782 
1783 	if ((addr & 0x7) != 0) {
1784 		dprintk("ptrace: unaligned register address 0x%lx\n", addr);
1785 		return -1;
1786 	}
1787 	if ((addr >= PT_NAT_BITS + 8 && addr < PT_F2) ||
1788 		(addr >= PT_R7 + 8 && addr < PT_B1) ||
1789 		(addr >= PT_AR_LC + 8 && addr < PT_CR_IPSR) ||
1790 		(addr >= PT_AR_SSD + 8 && addr < PT_DBR)) {
1791 		dprintk("ptrace: rejecting access to register "
1792 					"address 0x%lx\n", addr);
1793 		return -1;
1794 	}
1795 
1796 	switch (addr) {
1797 	case PT_F32 ... (PT_F127 + 15):
1798 		pos = addr - PT_F32 + ELF_FP_OFFSET(32);
1799 		break;
1800 	case PT_F2 ... (PT_F5 + 15):
1801 		pos = addr - PT_F2 + ELF_FP_OFFSET(2);
1802 		break;
1803 	case PT_F10 ... (PT_F31 + 15):
1804 		pos = addr - PT_F10 + ELF_FP_OFFSET(10);
1805 		break;
1806 	case PT_F6 ... (PT_F9 + 15):
1807 		pos = addr - PT_F6 + ELF_FP_OFFSET(6);
1808 		break;
1809 	}
1810 
1811 	if (pos != -1) {
1812 		unsigned reg = pos / sizeof(elf_fpreg_t);
1813 		int which_half = (pos / sizeof(unsigned long)) & 1;
1814 
1815 		if (reg < 32) { /* fr2-fr31 */
1816 			struct unw_frame_info info;
1817 			elf_fpreg_t fpreg;
1818 
1819 			memset(&info, 0, sizeof(info));
1820 			unw_init_from_blocked_task(&info, child);
1821 			if (unw_unwind_to_user(&info) < 0)
1822 				return 0;
1823 
1824 			if (unw_get_fr(&info, reg, &fpreg))
1825 				return -1;
1826 			if (write_access) {
1827 				fpreg.u.bits[which_half] = *data;
1828 				if (unw_set_fr(&info, reg, fpreg))
1829 					return -1;
1830 			} else {
1831 				*data = fpreg.u.bits[which_half];
1832 			}
1833 		} else { /* fph */
1834 			elf_fpreg_t *p = &child->thread.fph[reg - 32];
1835 			unsigned long *bits = &p->u.bits[which_half];
1836 
1837 			ia64_sync_fph(child);
1838 			if (write_access)
1839 				*bits = *data;
1840 			else if (child->thread.flags & IA64_THREAD_FPH_VALID)
1841 				*data = *bits;
1842 			else
1843 				*data = 0;
1844 		}
1845 		return 0;
1846 	}
1847 
1848 	switch (addr) {
1849 	case PT_NAT_BITS:
1850 		pos = ELF_NAT_OFFSET;
1851 		break;
1852 	case PT_R4 ... PT_R7:
1853 		pos = addr - PT_R4 + ELF_GR_OFFSET(4);
1854 		break;
1855 	case PT_B1 ... PT_B5:
1856 		pos = addr - PT_B1 + ELF_BR_OFFSET(1);
1857 		break;
1858 	case PT_AR_EC:
1859 		pos = ELF_AR_EC_OFFSET;
1860 		break;
1861 	case PT_AR_LC:
1862 		pos = ELF_AR_LC_OFFSET;
1863 		break;
1864 	case PT_CR_IPSR:
1865 		pos = ELF_CR_IPSR_OFFSET;
1866 		break;
1867 	case PT_CR_IIP:
1868 		pos = ELF_CR_IIP_OFFSET;
1869 		break;
1870 	case PT_CFM:
1871 		pos = ELF_CFM_OFFSET;
1872 		break;
1873 	case PT_AR_UNAT:
1874 		pos = ELF_AR_UNAT_OFFSET;
1875 		break;
1876 	case PT_AR_PFS:
1877 		pos = ELF_AR_PFS_OFFSET;
1878 		break;
1879 	case PT_AR_RSC:
1880 		pos = ELF_AR_RSC_OFFSET;
1881 		break;
1882 	case PT_AR_RNAT:
1883 		pos = ELF_AR_RNAT_OFFSET;
1884 		break;
1885 	case PT_AR_BSPSTORE:
1886 		pos = ELF_AR_BSPSTORE_OFFSET;
1887 		break;
1888 	case PT_PR:
1889 		pos = ELF_PR_OFFSET;
1890 		break;
1891 	case PT_B6:
1892 		pos = ELF_BR_OFFSET(6);
1893 		break;
1894 	case PT_AR_BSP:
1895 		pos = ELF_AR_BSP_OFFSET;
1896 		break;
1897 	case PT_R1 ... PT_R3:
1898 		pos = addr - PT_R1 + ELF_GR_OFFSET(1);
1899 		break;
1900 	case PT_R12 ... PT_R15:
1901 		pos = addr - PT_R12 + ELF_GR_OFFSET(12);
1902 		break;
1903 	case PT_R8 ... PT_R11:
1904 		pos = addr - PT_R8 + ELF_GR_OFFSET(8);
1905 		break;
1906 	case PT_R16 ... PT_R31:
1907 		pos = addr - PT_R16 + ELF_GR_OFFSET(16);
1908 		break;
1909 	case PT_AR_CCV:
1910 		pos = ELF_AR_CCV_OFFSET;
1911 		break;
1912 	case PT_AR_FPSR:
1913 		pos = ELF_AR_FPSR_OFFSET;
1914 		break;
1915 	case PT_B0:
1916 		pos = ELF_BR_OFFSET(0);
1917 		break;
1918 	case PT_B7:
1919 		pos = ELF_BR_OFFSET(7);
1920 		break;
1921 	case PT_AR_CSD:
1922 		pos = ELF_AR_CSD_OFFSET;
1923 		break;
1924 	case PT_AR_SSD:
1925 		pos = ELF_AR_SSD_OFFSET;
1926 		break;
1927 	}
1928 
1929 	if (pos != -1) {
1930 		struct unw_frame_info info;
1931 
1932 		memset(&info, 0, sizeof(info));
1933 		unw_init_from_blocked_task(&info, child);
1934 		if (unw_unwind_to_user(&info) < 0)
1935 			return 0;
1936 
1937 		return access_elf_reg(child, &info, pos, data, write_access);
1938 	}
1939 
1940 	/* access debug registers */
1941 	if (addr >= PT_IBR) {
1942 		regnum = (addr - PT_IBR) >> 3;
1943 		ptr = &child->thread.ibr[0];
1944 	} else {
1945 		regnum = (addr - PT_DBR) >> 3;
1946 		ptr = &child->thread.dbr[0];
1947 	}
1948 
1949 	if (regnum >= 8) {
1950 		dprintk("ptrace: rejecting access to register "
1951 				"address 0x%lx\n", addr);
1952 		return -1;
1953 	}
1954 
1955 	if (!(child->thread.flags & IA64_THREAD_DBG_VALID)) {
1956 		child->thread.flags |= IA64_THREAD_DBG_VALID;
1957 		memset(child->thread.dbr, 0,
1958 				sizeof(child->thread.dbr));
1959 		memset(child->thread.ibr, 0,
1960 				sizeof(child->thread.ibr));
1961 	}
1962 
1963 	ptr += regnum;
1964 
1965 	if ((regnum & 1) && write_access) {
1966 		/* don't let the user set kernel-level breakpoints: */
1967 		*ptr = *data & ~(7UL << 56);
1968 		return 0;
1969 	}
1970 	if (write_access)
1971 		*ptr = *data;
1972 	else
1973 		*data = *ptr;
1974 	return 0;
1975 }
1976 
1977 static const struct user_regset native_regsets[] = {
1978 	{
1979 		.core_note_type = NT_PRSTATUS,
1980 		.n = ELF_NGREG,
1981 		.size = sizeof(elf_greg_t), .align = sizeof(elf_greg_t),
1982 		.regset_get = gpregs_get, .set = gpregs_set,
1983 		.writeback = gpregs_writeback
1984 	},
1985 	{
1986 		.core_note_type = NT_PRFPREG,
1987 		.n = ELF_NFPREG,
1988 		.size = sizeof(elf_fpreg_t), .align = sizeof(elf_fpreg_t),
1989 		.regset_get = fpregs_get, .set = fpregs_set, .active = fpregs_active
1990 	},
1991 };
1992 
1993 static const struct user_regset_view user_ia64_view = {
1994 	.name = "ia64",
1995 	.e_machine = EM_IA_64,
1996 	.regsets = native_regsets, .n = ARRAY_SIZE(native_regsets)
1997 };
1998 
1999 const struct user_regset_view *task_user_regset_view(struct task_struct *tsk)
2000 {
2001 	return &user_ia64_view;
2002 }
2003 
2004 struct syscall_get_set_args {
2005 	unsigned int i;
2006 	unsigned int n;
2007 	unsigned long *args;
2008 	struct pt_regs *regs;
2009 	int rw;
2010 };
2011 
2012 static void syscall_get_set_args_cb(struct unw_frame_info *info, void *data)
2013 {
2014 	struct syscall_get_set_args *args = data;
2015 	struct pt_regs *pt = args->regs;
2016 	unsigned long *krbs, cfm, ndirty, nlocals, nouts;
2017 	int i, count;
2018 
2019 	if (unw_unwind_to_user(info) < 0)
2020 		return;
2021 
2022 	/*
2023 	 * We get here via a few paths:
2024 	 * - break instruction: cfm is shared with caller.
2025 	 *   syscall args are in out= regs, locals are non-empty.
2026 	 * - epsinstruction: cfm is set by br.call
2027 	 *   locals don't exist.
2028 	 *
2029 	 * For both cases argguments are reachable in cfm.sof - cfm.sol.
2030 	 * CFM: [ ... | sor: 17..14 | sol : 13..7 | sof : 6..0 ]
2031 	 */
2032 	cfm = pt->cr_ifs;
2033 	nlocals = (cfm >> 7) & 0x7f; /* aka sol */
2034 	nouts = (cfm & 0x7f) - nlocals; /* aka sof - sol */
2035 	krbs = (unsigned long *)info->task + IA64_RBS_OFFSET/8;
2036 	ndirty = ia64_rse_num_regs(krbs, krbs + (pt->loadrs >> 19));
2037 
2038 	count = 0;
2039 	if (in_syscall(pt))
2040 		count = min_t(int, args->n, nouts);
2041 
2042 	/* Iterate over outs. */
2043 	for (i = 0; i < count; i++) {
2044 		int j = ndirty + nlocals + i + args->i;
2045 		if (args->rw)
2046 			*ia64_rse_skip_regs(krbs, j) = args->args[i];
2047 		else
2048 			args->args[i] = *ia64_rse_skip_regs(krbs, j);
2049 	}
2050 
2051 	if (!args->rw) {
2052 		while (i < args->n) {
2053 			args->args[i] = 0;
2054 			i++;
2055 		}
2056 	}
2057 }
2058 
2059 void ia64_syscall_get_set_arguments(struct task_struct *task,
2060 	struct pt_regs *regs, unsigned long *args, int rw)
2061 {
2062 	struct syscall_get_set_args data = {
2063 		.i = 0,
2064 		.n = 6,
2065 		.args = args,
2066 		.regs = regs,
2067 		.rw = rw,
2068 	};
2069 
2070 	if (task == current)
2071 		unw_init_running(syscall_get_set_args_cb, &data);
2072 	else {
2073 		struct unw_frame_info ufi;
2074 		memset(&ufi, 0, sizeof(ufi));
2075 		unw_init_from_blocked_task(&ufi, task);
2076 		syscall_get_set_args_cb(&ufi, &data);
2077 	}
2078 }
2079