summaryrefslogtreecommitdiff
path: root/arch/ia64/kernel/process.c
blob: 913d9a01cbf9b3430d7009038060eb836a9a9666 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
// SPDX-License-Identifier: GPL-2.0
/*
 * Architecture-specific setup.
 *
 * Copyright (C) 1998-2003 Hewlett-Packard Co
 *	David Mosberger-Tang <davidm@hpl.hp.com>
 * 04/11/17 Ashok Raj	<ashok.raj@intel.com> Added CPU Hotplug Support
 *
 * 2005-10-07 Keith Owens <kaos@sgi.com>
 *	      Add notify_die() hooks.
 */
#include <linux/cpu.h>
#include <linux/pm.h>
#include <linux/elf.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/personality.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/sched/hotplug.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <linux/stddef.h>
#include <linux/thread_info.h>
#include <linux/unistd.h>
#include <linux/efi.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/kdebug.h>
#include <linux/utsname.h>
#include <linux/tracehook.h>
#include <linux/rcupdate.h>

#include <asm/cpu.h>
#include <asm/delay.h>
#include <asm/elf.h>
#include <asm/irq.h>
#include <asm/kexec.h>
#include <asm/pgalloc.h>
#include <asm/processor.h>
#include <asm/sal.h>
#include <asm/switch_to.h>
#include <asm/tlbflush.h>
#include <linux/uaccess.h>
#include <asm/unwind.h>
#include <asm/user.h>

#include "entry.h"

#ifdef CONFIG_PERFMON
# include <asm/perfmon.h>
#endif

#include "sigframe.h"

void (*ia64_mark_idle)(int);

unsigned long boot_option_idle_override = IDLE_NO_OVERRIDE;
EXPORT_SYMBOL(boot_option_idle_override);
void (*pm_power_off) (void);
EXPORT_SYMBOL(pm_power_off);

static void
ia64_do_show_stack (struct unw_frame_info *info, void *arg)
{
	unsigned long ip, sp, bsp;
	const char *loglvl = arg;

	printk("%s\nCall Trace:\n", loglvl);
	do {
		unw_get_ip(info, &ip);
		if (ip == 0)
			break;

		unw_get_sp(info, &sp);
		unw_get_bsp(info, &bsp);
		printk("%s [<%016lx>] %pS\n"
			 "                                sp=%016lx bsp=%016lx\n",
			 loglvl, ip, (void *)ip, sp, bsp);
	} while (unw_unwind(info) >= 0);
}

void
show_stack_loglvl (struct task_struct *task, unsigned long *sp,
		   const char *loglvl)
{
	if (!task)
		unw_init_running(ia64_do_show_stack, (void *)loglvl);
	else {
		struct unw_frame_info info;

		unw_init_from_blocked_task(&info, task);
		ia64_do_show_stack(&info, (void *)loglvl);
	}
}

void
show_stack (struct task_struct *task, unsigned long *sp)
{
	show_stack_loglvl(task, sp, KERN_DEFAULT);
}

void
show_regs (struct pt_regs *regs)
{
	unsigned long ip = regs->cr_iip + ia64_psr(regs)->ri;

	print_modules();
	printk("\n");
	show_regs_print_info(KERN_DEFAULT);
	printk("psr : %016lx ifs : %016lx ip  : [<%016lx>]    %s (%s)\n",
	       regs->cr_ipsr, regs->cr_ifs, ip, print_tainted(),
	       init_utsname()->release);
	printk("ip is at %pS\n", (void *)ip);
	printk("unat: %016lx pfs : %016lx rsc : %016lx\n",
	       regs->ar_unat, regs->ar_pfs, regs->ar_rsc);
	printk("rnat: %016lx bsps: %016lx pr  : %016lx\n",
	       regs->ar_rnat, regs->ar_bspstore, regs->pr);
	printk("ldrs: %016lx ccv : %016lx fpsr: %016lx\n",
	       regs->loadrs, regs->ar_ccv, regs->ar_fpsr);
	printk("csd : %016lx ssd : %016lx\n", regs->ar_csd, regs->ar_ssd);
	printk("b0  : %016lx b6  : %016lx b7  : %016lx\n", regs->b0, regs->b6, regs->b7);
	printk("f6  : %05lx%016lx f7  : %05lx%016lx\n",
	       regs->f6.u.bits[1], regs->f6.u.bits[0],
	       regs->f7.u.bits[1], regs->f7.u.bits[0]);
	printk("f8  : %05lx%016lx f9  : %05lx%016lx\n",
	       regs->f8.u.bits[1], regs->f8.u.bits[0],
	       regs->f9.u.bits[1], regs->f9.u.bits[0]);
	printk("f10 : %05lx%016lx f11 : %05lx%016lx\n",
	       regs->f10.u.bits[1], regs->f10.u.bits[0],
	       regs->f11.u.bits[1], regs->f11.u.bits[0]);

	printk("r1  : %016lx r2  : %016lx r3  : %016lx\n", regs->r1, regs->r2, regs->r3);
	printk("r8  : %016lx r9  : %016lx r10 : %016lx\n", regs->r8, regs->r9, regs->r10);
	printk("r11 : %016lx r12 : %016lx r13 : %016lx\n", regs->r11, regs->r12, regs->r13);
	printk("r14 : %016lx r15 : %016lx r16 : %016lx\n", regs->r14, regs->r15, regs->r16);
	printk("r17 : %016lx r18 : %016lx r19 : %016lx\n", regs->r17, regs->r18, regs->r19);
	printk("r20 : %016lx r21 : %016lx r22 : %016lx\n", regs->r20, regs->r21, regs->r22);
	printk("r23 : %016lx r24 : %016lx r25 : %016lx\n", regs->r23, regs->r24, regs->r25);
	printk("r26 : %016lx r27 : %016lx r28 : %016lx\n", regs->r26, regs->r27, regs->r28);
	printk("r29 : %016lx r30 : %016lx r31 : %016lx\n", regs->r29, regs->r30, regs->r31);

	if (user_mode(regs)) {
		/* print the stacked registers */
		unsigned long val, *bsp, ndirty;
		int i, sof, is_nat = 0;

		sof = regs->cr_ifs & 0x7f;	/* size of frame */
		ndirty = (regs->loadrs >> 19);
		bsp = ia64_rse_skip_regs((unsigned long *) regs->ar_bspstore, ndirty);
		for (i = 0; i < sof; ++i) {
			get_user(val, (unsigned long __user *) ia64_rse_skip_regs(bsp, i));
			printk("r%-3u:%c%016lx%s", 32 + i, is_nat ? '*' : ' ', val,
			       ((i == sof - 1) || (i % 3) == 2) ? "\n" : " ");
		}
	} else
		show_stack(NULL, NULL);
}

/* local support for deprecated console_print */
void
console_print(const char *s)
{
	printk(KERN_EMERG "%s", s);
}

void
do_notify_resume_user(sigset_t *unused, struct sigscratch *scr, long in_syscall)
{
	if (fsys_mode(current, &scr->pt)) {
		/*
		 * defer signal-handling etc. until we return to
		 * privilege-level 0.
		 */
		if (!ia64_psr(&scr->pt)->lp)
			ia64_psr(&scr->pt)->lp = 1;
		return;
	}

#ifdef CONFIG_PERFMON
	if (current->thread.pfm_needs_checking)
		/*
		 * Note: pfm_handle_work() allow us to call it with interrupts
		 * disabled, and may enable interrupts within the function.
		 */
		pfm_handle_work();
#endif

	/* deal with pending signal delivery */
	if (test_thread_flag(TIF_SIGPENDING)) {
		local_irq_enable();	/* force interrupt enable */
		ia64_do_signal(scr, in_syscall);
	}

	if (test_and_clear_thread_flag(TIF_NOTIFY_RESUME)) {
		local_irq_enable();	/* force interrupt enable */
		tracehook_notify_resume(&scr->pt);
	}

	/* copy user rbs to kernel rbs */
	if (unlikely(test_thread_flag(TIF_RESTORE_RSE))) {
		local_irq_enable();	/* force interrupt enable */
		ia64_sync_krbs();
	}

	local_irq_disable();	/* force interrupt disable */
}

static int __init nohalt_setup(char * str)
{
	cpu_idle_poll_ctrl(true);
	return 1;
}
__setup("nohalt", nohalt_setup);

#ifdef CONFIG_HOTPLUG_CPU
/* We don't actually take CPU down, just spin without interrupts. */
static inline void play_dead(void)
{
	unsigned int this_cpu = smp_processor_id();

	/* Ack it */
	__this_cpu_write(cpu_state, CPU_DEAD);

	max_xtp();
	local_irq_disable();
	idle_task_exit();
	ia64_jump_to_sal(&sal_boot_rendez_state[this_cpu]);
	/*
	 * The above is a point of no-return, the processor is
	 * expected to be in SAL loop now.
	 */
	BUG();
}
#else
static inline void play_dead(void)
{
	BUG();
}
#endif /* CONFIG_HOTPLUG_CPU */

void arch_cpu_idle_dead(void)
{
	play_dead();
}

void arch_cpu_idle(void)
{
	void (*mark_idle)(int) = ia64_mark_idle;

#ifdef CONFIG_SMP
	min_xtp();
#endif
	rmb();
	if (mark_idle)
		(*mark_idle)(1);

	safe_halt();

	if (mark_idle)
		(*mark_idle)(0);
#ifdef CONFIG_SMP
	normal_xtp();
#endif
}

void
ia64_save_extra (struct task_struct *task)
{
#ifdef CONFIG_PERFMON
	unsigned long info;
#endif

	if ((task->thread.flags & IA64_THREAD_DBG_VALID) != 0)
		ia64_save_debug_regs(&task->thread.dbr[0]);

#ifdef CONFIG_PERFMON
	if ((task->thread.flags & IA64_THREAD_PM_VALID) != 0)
		pfm_save_regs(task);

	info = __this_cpu_read(pfm_syst_info);
	if (info & PFM_CPUINFO_SYST_WIDE)
		pfm_syst_wide_update_task(task, info, 0);
#endif
}

void
ia64_load_extra (struct task_struct *task)
{
#ifdef CONFIG_PERFMON
	unsigned long info;
#endif

	if ((task->thread.flags & IA64_THREAD_DBG_VALID) != 0)
		ia64_load_debug_regs(&task->thread.dbr[0]);

#ifdef CONFIG_PERFMON
	if ((task->thread.flags & IA64_THREAD_PM_VALID) != 0)
		pfm_load_regs(task);

	info = __this_cpu_read(pfm_syst_info);
	if (info & PFM_CPUINFO_SYST_WIDE) 
		pfm_syst_wide_update_task(task, info, 1);
#endif
}

/*
 * Copy the state of an ia-64 thread.
 *
 * We get here through the following  call chain:
 *
 *	from user-level:	from kernel:
 *
 *	<clone syscall>	        <some kernel call frames>
 *	sys_clone		   :
 *	do_fork			do_fork
 *	copy_thread		copy_thread
 *
 * This means that the stack layout is as follows:
 *
 *	+---------------------+ (highest addr)
 *	|   struct pt_regs    |
 *	+---------------------+
 *	| struct switch_stack |
 *	+---------------------+
 *	|                     |
 *	|    memory stack     |
 *	|                     | <-- sp (lowest addr)
 *	+---------------------+
 *
 * Observe that we copy the unat values that are in pt_regs and switch_stack.  Spilling an
 * integer to address X causes bit N in ar.unat to be set to the NaT bit of the register,
 * with N=(X & 0x1ff)/8.  Thus, copying the unat value preserves the NaT bits ONLY if the
 * pt_regs structure in the parent is congruent to that of the child, modulo 512.  Since
 * the stack is page aligned and the page size is at least 4KB, this is always the case,
 * so there is nothing to worry about.
 */
int
copy_thread(unsigned long clone_flags,
	     unsigned long user_stack_base, unsigned long user_stack_size,
	     struct task_struct *p)
{
	extern char ia64_ret_from_clone;
	struct switch_stack *child_stack, *stack;
	unsigned long rbs, child_rbs, rbs_size;
	struct pt_regs *child_ptregs;
	struct pt_regs *regs = current_pt_regs();
	int retval = 0;

	child_ptregs = (struct pt_regs *) ((unsigned long) p + IA64_STK_OFFSET) - 1;
	child_stack = (struct switch_stack *) child_ptregs - 1;

	rbs = (unsigned long) current + IA64_RBS_OFFSET;
	child_rbs = (unsigned long) p + IA64_RBS_OFFSET;

	/* copy parts of thread_struct: */
	p->thread.ksp = (unsigned long) child_stack - 16;

	/*
	 * NOTE: The calling convention considers all floating point
	 * registers in the high partition (fph) to be scratch.  Since
	 * the only way to get to this point is through a system call,
	 * we know that the values in fph are all dead.  Hence, there
	 * is no need to inherit the fph state from the parent to the
	 * child and all we have to do is to make sure that
	 * IA64_THREAD_FPH_VALID is cleared in the child.
	 *
	 * XXX We could push this optimization a bit further by
	 * clearing IA64_THREAD_FPH_VALID on ANY system call.
	 * However, it's not clear this is worth doing.  Also, it
	 * would be a slight deviation from the normal Linux system
	 * call behavior where scratch registers are preserved across
	 * system calls (unless used by the system call itself).
	 */
#	define THREAD_FLAGS_TO_CLEAR	(IA64_THREAD_FPH_VALID | IA64_THREAD_DBG_VALID \
					 | IA64_THREAD_PM_VALID)
#	define THREAD_FLAGS_TO_SET	0
	p->thread.flags = ((current->thread.flags & ~THREAD_FLAGS_TO_CLEAR)
			   | THREAD_FLAGS_TO_SET);

	ia64_drop_fpu(p);	/* don't pick up stale state from a CPU's fph */

	if (unlikely(p->flags & PF_KTHREAD)) {
		if (unlikely(!user_stack_base)) {
			/* fork_idle() called us */
			return 0;
		}
		memset(child_stack, 0, sizeof(*child_ptregs) + sizeof(*child_stack));
		child_stack->r4 = user_stack_base;	/* payload */
		child_stack->r5 = user_stack_size;	/* argument */
		/*
		 * Preserve PSR bits, except for bits 32-34 and 37-45,
		 * which we can't read.
		 */
		child_ptregs->cr_ipsr = ia64_getreg(_IA64_REG_PSR) | IA64_PSR_BN;
		/* mark as valid, empty frame */
		child_ptregs->cr_ifs = 1UL << 63;
		child_stack->ar_fpsr = child_ptregs->ar_fpsr
			= ia64_getreg(_IA64_REG_AR_FPSR);
		child_stack->pr = (1 << PRED_KERNEL_STACK);
		child_stack->ar_bspstore = child_rbs;
		child_stack->b0 = (unsigned long) &ia64_ret_from_clone;

		/* stop some PSR bits from being inherited.
		 * the psr.up/psr.pp bits must be cleared on fork but inherited on execve()
		 * therefore we must specify them explicitly here and not include them in
		 * IA64_PSR_BITS_TO_CLEAR.
		 */
		child_ptregs->cr_ipsr = ((child_ptregs->cr_ipsr | IA64_PSR_BITS_TO_SET)
				 & ~(IA64_PSR_BITS_TO_CLEAR | IA64_PSR_PP | IA64_PSR_UP));

		return 0;
	}
	stack = ((struct switch_stack *) regs) - 1;
	/* copy parent's switch_stack & pt_regs to child: */
	memcpy(child_stack, stack, sizeof(*child_ptregs) + sizeof(*child_stack));

	/* copy the parent's register backing store to the child: */
	rbs_size = stack->ar_bspstore - rbs;
	memcpy((void *) child_rbs, (void *) rbs, rbs_size);
	if (clone_flags & CLONE_SETTLS)
		child_ptregs->r13 = regs->r16;	/* see sys_clone2() in entry.S */
	if (user_stack_base) {
		child_ptregs->r12 = user_stack_base + user_stack_size - 16;
		child_ptregs->ar_bspstore = user_stack_base;
		child_ptregs->ar_rnat = 0;
		child_ptregs->loadrs = 0;
	}
	child_stack->ar_bspstore = child_rbs + rbs_size;
	child_stack->b0 = (unsigned long) &ia64_ret_from_clone;

	/* stop some PSR bits from being inherited.
	 * the psr.up/psr.pp bits must be cleared on fork but inherited on execve()
	 * therefore we must specify them explicitly here and not include them in
	 * IA64_PSR_BITS_TO_CLEAR.
	 */
	child_ptregs->cr_ipsr = ((child_ptregs->cr_ipsr | IA64_PSR_BITS_TO_SET)
				 & ~(IA64_PSR_BITS_TO_CLEAR | IA64_PSR_PP | IA64_PSR_UP));

#ifdef CONFIG_PERFMON
	if (current->thread.pfm_context)
		pfm_inherit(p, child_ptregs);
#endif
	return retval;
}

static void
do_copy_task_regs (struct task_struct *task, struct unw_frame_info *info, void *arg)
{
	unsigned long mask, sp, nat_bits = 0, ar_rnat, urbs_end, cfm;
	unsigned long uninitialized_var(ip);	/* GCC be quiet */
	elf_greg_t *dst = arg;
	struct pt_regs *pt;
	char nat;
	int i;

	memset(dst, 0, sizeof(elf_gregset_t));	/* don't leak any kernel bits to user-level */

	if (unw_unwind_to_user(info) < 0)
		return;

	unw_get_sp(info, &sp);
	pt = (struct pt_regs *) (sp + 16);

	urbs_end = ia64_get_user_rbs_end(task, pt, &cfm);

	if (ia64_sync_user_rbs(task, info->sw, pt->ar_bspstore, urbs_end) < 0)
		return;

	ia64_peek(task, info->sw, urbs_end, (long) ia64_rse_rnat_addr((long *) urbs_end),
		  &ar_rnat);

	/*
	 * coredump format:
	 *	r0-r31
	 *	NaT bits (for r0-r31; bit N == 1 iff rN is a NaT)
	 *	predicate registers (p0-p63)
	 *	b0-b7
	 *	ip cfm user-mask
	 *	ar.rsc ar.bsp ar.bspstore ar.rnat
	 *	ar.ccv ar.unat ar.fpsr ar.pfs ar.lc ar.ec
	 */

	/* r0 is zero */
	for (i = 1, mask = (1UL << i); i < 32; ++i) {
		unw_get_gr(info, i, &dst[i], &nat);
		if (nat)
			nat_bits |= mask;
		mask <<= 1;
	}
	dst[32] = nat_bits;
	unw_get_pr(info, &dst[33]);

	for (i = 0; i < 8; ++i)
		unw_get_br(info, i, &dst[34 + i]);

	unw_get_rp(info, &ip);
	dst[42] = ip + ia64_psr(pt)->ri;
	dst[43] = cfm;
	dst[44] = pt->cr_ipsr & IA64_PSR_UM;

	unw_get_ar(info, UNW_AR_RSC, &dst[45]);
	/*
	 * For bsp and bspstore, unw_get_ar() would return the kernel
	 * addresses, but we need the user-level addresses instead:
	 */
	dst[46] = urbs_end;	/* note: by convention PT_AR_BSP points to the end of the urbs! */
	dst[47] = pt->ar_bspstore;
	dst[48] = ar_rnat;
	unw_get_ar(info, UNW_AR_CCV, &dst[49]);
	unw_get_ar(info, UNW_AR_UNAT, &dst[50]);
	unw_get_ar(info, UNW_AR_FPSR, &dst[51]);
	dst[52] = pt->ar_pfs;	/* UNW_AR_PFS is == to pt->cr_ifs for interrupt frames */
	unw_get_ar(info, UNW_AR_LC, &dst[53]);
	unw_get_ar(info, UNW_AR_EC, &dst[54]);
	unw_get_ar(info, UNW_AR_CSD, &dst[55]);
	unw_get_ar(info, UNW_AR_SSD, &dst[56]);
}

void
do_dump_task_fpu (struct task_struct *task, struct unw_frame_info *info, void *arg)
{
	elf_fpreg_t *dst = arg;
	int i;

	memset(dst, 0, sizeof(elf_fpregset_t));	/* don't leak any "random" bits */

	if (unw_unwind_to_user(info) < 0)
		return;

	/* f0 is 0.0, f1 is 1.0 */

	for (i = 2; i < 32; ++i)
		unw_get_fr(info, i, dst + i);

	ia64_flush_fph(task);
	if ((task->thread.flags & IA64_THREAD_FPH_VALID) != 0)
		memcpy(dst + 32, task->thread.fph, 96*16);
}

void
do_copy_regs (struct unw_frame_info *info, void *arg)
{
	do_copy_task_regs(current, info, arg);
}

void
do_dump_fpu (struct unw_frame_info *info, void *arg)
{
	do_dump_task_fpu(current, info, arg);
}

void
ia64_elf_core_copy_regs (struct pt_regs *pt, elf_gregset_t dst)
{
	unw_init_running(do_copy_regs, dst);
}

int
dump_fpu (struct pt_regs *pt, elf_fpregset_t dst)
{
	unw_init_running(do_dump_fpu, dst);
	return 1;	/* f0-f31 are always valid so we always return 1 */
}

/*
 * Flush thread state.  This is called when a thread does an execve().
 */
void
flush_thread (void)
{
	/* drop floating-point and debug-register state if it exists: */
	current->thread.flags &= ~(IA64_THREAD_FPH_VALID | IA64_THREAD_DBG_VALID);
	ia64_drop_fpu(current);
}

/*
 * Clean up state associated with a thread.  This is called when
 * the thread calls exit().
 */
void
exit_thread (struct task_struct *tsk)
{

	ia64_drop_fpu(tsk);
#ifdef CONFIG_PERFMON
       /* if needed, stop monitoring and flush state to perfmon context */
	if (tsk->thread.pfm_context)
		pfm_exit_thread(tsk);

	/* free debug register resources */
	if (tsk->thread.flags & IA64_THREAD_DBG_VALID)
		pfm_release_debug_registers(tsk);
#endif
}

unsigned long
get_wchan (struct task_struct *p)
{
	struct unw_frame_info info;
	unsigned long ip;
	int count = 0;

	if (!p || p == current || p->state == TASK_RUNNING)
		return 0;

	/*
	 * Note: p may not be a blocked task (it could be current or
	 * another process running on some other CPU.  Rather than
	 * trying to determine if p is really blocked, we just assume
	 * it's blocked and rely on the unwind routines to fail
	 * gracefully if the process wasn't really blocked after all.
	 * --davidm 99/12/15
	 */
	unw_init_from_blocked_task(&info, p);
	do {
		if (p->state == TASK_RUNNING)
			return 0;
		if (unw_unwind(&info) < 0)
			return 0;
		unw_get_ip(&info, &ip);
		if (!in_sched_functions(ip))
			return ip;
	} while (count++ < 16);
	return 0;
}

void
cpu_halt (void)
{
	pal_power_mgmt_info_u_t power_info[8];
	unsigned long min_power;
	int i, min_power_state;

	if (ia64_pal_halt_info(power_info) != 0)
		return;

	min_power_state = 0;
	min_power = power_info[0].pal_power_mgmt_info_s.power_consumption;
	for (i = 1; i < 8; ++i)
		if (power_info[i].pal_power_mgmt_info_s.im
		    && power_info[i].pal_power_mgmt_info_s.power_consumption < min_power) {
			min_power = power_info[i].pal_power_mgmt_info_s.power_consumption;
			min_power_state = i;
		}

	while (1)
		ia64_pal_halt(min_power_state);
}

void machine_shutdown(void)
{
	smp_shutdown_nonboot_cpus(reboot_cpu);

#ifdef CONFIG_KEXEC
	kexec_disable_iosapic();
#endif
}

void
machine_restart (char *restart_cmd)
{
	(void) notify_die(DIE_MACHINE_RESTART, restart_cmd, NULL, 0, 0, 0);
	efi_reboot(REBOOT_WARM, NULL);
}

void
machine_halt (void)
{
	(void) notify_die(DIE_MACHINE_HALT, "", NULL, 0, 0, 0);
	cpu_halt();
}

void
machine_power_off (void)
{
	if (pm_power_off)
		pm_power_off();
	machine_halt();
}

EXPORT_SYMBOL(ia64_delay_loop);