aboutsummaryrefslogtreecommitdiff
path: root/arch/sparc/kernel/process_64.c
blob: d959cd0a4aa4c520f3dba28e6b1cb6060726c100 (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
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
/*  arch/sparc64/kernel/process.c
 *
 *  Copyright (C) 1995, 1996, 2008 David S. Miller (davem@davemloft.net)
 *  Copyright (C) 1996       Eddie C. Dost   (ecd@skynet.be)
 *  Copyright (C) 1997, 1998 Jakub Jelinek   (jj@sunsite.mff.cuni.cz)
 */

/*
 * This file handles the architecture-dependent parts of process handling..
 */

#include <stdarg.h>

#include <linux/errno.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/smp.h>
#include <linux/stddef.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/user.h>
#include <linux/delay.h>
#include <linux/compat.h>
#include <linux/tick.h>
#include <linux/init.h>
#include <linux/cpu.h>
#include <linux/elfcore.h>
#include <linux/sysrq.h>
#include <linux/nmi.h>

#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/pstate.h>
#include <asm/elf.h>
#include <asm/fpumacro.h>
#include <asm/head.h>
#include <asm/cpudata.h>
#include <asm/mmu_context.h>
#include <asm/unistd.h>
#include <asm/hypervisor.h>
#include <asm/syscalls.h>
#include <asm/irq_regs.h>
#include <asm/smp.h>

#include "kstack.h"

static void sparc64_yield(int cpu)
{
	if (tlb_type != hypervisor) {
		touch_nmi_watchdog();
		return;
	}

	clear_thread_flag(TIF_POLLING_NRFLAG);
	smp_mb__after_clear_bit();

	while (!need_resched() && !cpu_is_offline(cpu)) {
		unsigned long pstate;

		/* Disable interrupts. */
		__asm__ __volatile__(
			"rdpr %%pstate, %0\n\t"
			"andn %0, %1, %0\n\t"
			"wrpr %0, %%g0, %%pstate"
			: "=&r" (pstate)
			: "i" (PSTATE_IE));

		if (!need_resched() && !cpu_is_offline(cpu))
			sun4v_cpu_yield();

		/* Re-enable interrupts. */
		__asm__ __volatile__(
			"rdpr %%pstate, %0\n\t"
			"or %0, %1, %0\n\t"
			"wrpr %0, %%g0, %%pstate"
			: "=&r" (pstate)
			: "i" (PSTATE_IE));
	}

	set_thread_flag(TIF_POLLING_NRFLAG);
}

/* The idle loop on sparc64. */
void cpu_idle(void)
{
	int cpu = smp_processor_id();

	set_thread_flag(TIF_POLLING_NRFLAG);

	while(1) {
		tick_nohz_stop_sched_tick(1);

		while (!need_resched() && !cpu_is_offline(cpu))
			sparc64_yield(cpu);

		tick_nohz_restart_sched_tick();

		preempt_enable_no_resched();

#ifdef CONFIG_HOTPLUG_CPU
		if (cpu_is_offline(cpu))
			cpu_play_dead();
#endif

		schedule();
		preempt_disable();
	}
}

#ifdef CONFIG_COMPAT
static void show_regwindow32(struct pt_regs *regs)
{
	struct reg_window32 __user *rw;
	struct reg_window32 r_w;
	mm_segment_t old_fs;
	
	__asm__ __volatile__ ("flushw");
	rw = compat_ptr((unsigned)regs->u_regs[14]);
	old_fs = get_fs();
	set_fs (USER_DS);
	if (copy_from_user (&r_w, rw, sizeof(r_w))) {
		set_fs (old_fs);
		return;
	}

	set_fs (old_fs);			
	printk("l0: %08x l1: %08x l2: %08x l3: %08x "
	       "l4: %08x l5: %08x l6: %08x l7: %08x\n",
	       r_w.locals[0], r_w.locals[1], r_w.locals[2], r_w.locals[3],
	       r_w.locals[4], r_w.locals[5], r_w.locals[6], r_w.locals[7]);
	printk("i0: %08x i1: %08x i2: %08x i3: %08x "
	       "i4: %08x i5: %08x i6: %08x i7: %08x\n",
	       r_w.ins[0], r_w.ins[1], r_w.ins[2], r_w.ins[3],
	       r_w.ins[4], r_w.ins[5], r_w.ins[6], r_w.ins[7]);
}
#else
#define show_regwindow32(regs)	do { } while (0)
#endif

static void show_regwindow(struct pt_regs *regs)
{
	struct reg_window __user *rw;
	struct reg_window *rwk;
	struct reg_window r_w;
	mm_segment_t old_fs;

	if ((regs->tstate & TSTATE_PRIV) || !(test_thread_flag(TIF_32BIT))) {
		__asm__ __volatile__ ("flushw");
		rw = (struct reg_window __user *)
			(regs->u_regs[14] + STACK_BIAS);
		rwk = (struct reg_window *)
			(regs->u_regs[14] + STACK_BIAS);
		if (!(regs->tstate & TSTATE_PRIV)) {
			old_fs = get_fs();
			set_fs (USER_DS);
			if (copy_from_user (&r_w, rw, sizeof(r_w))) {
				set_fs (old_fs);
				return;
			}
			rwk = &r_w;
			set_fs (old_fs);			
		}
	} else {
		show_regwindow32(regs);
		return;
	}
	printk("l0: %016lx l1: %016lx l2: %016lx l3: %016lx\n",
	       rwk->locals[0], rwk->locals[1], rwk->locals[2], rwk->locals[3]);
	printk("l4: %016lx l5: %016lx l6: %016lx l7: %016lx\n",
	       rwk->locals[4], rwk->locals[5], rwk->locals[6], rwk->locals[7]);
	printk("i0: %016lx i1: %016lx i2: %016lx i3: %016lx\n",
	       rwk->ins[0], rwk->ins[1], rwk->ins[2], rwk->ins[3]);
	printk("i4: %016lx i5: %016lx i6: %016lx i7: %016lx\n",
	       rwk->ins[4], rwk->ins[5], rwk->ins[6], rwk->ins[7]);
	if (regs->tstate & TSTATE_PRIV)
		printk("I7: <%pS>\n", (void *) rwk->ins[7]);
}

void show_regs(struct pt_regs *regs)
{
	printk("TSTATE: %016lx TPC: %016lx TNPC: %016lx Y: %08x    %s\n", regs->tstate,
	       regs->tpc, regs->tnpc, regs->y, print_tainted());
	printk("TPC: <%pS>\n", (void *) regs->tpc);
	printk("g0: %016lx g1: %016lx g2: %016lx g3: %016lx\n",
	       regs->u_regs[0], regs->u_regs[1], regs->u_regs[2],
	       regs->u_regs[3]);
	printk("g4: %016lx g5: %016lx g6: %016lx g7: %016lx\n",
	       regs->u_regs[4], regs->u_regs[5], regs->u_regs[6],
	       regs->u_regs[7]);
	printk("o0: %016lx o1: %016lx o2: %016lx o3: %016lx\n",
	       regs->u_regs[8], regs->u_regs[9], regs->u_regs[10],
	       regs->u_regs[11]);
	printk("o4: %016lx o5: %016lx sp: %016lx ret_pc: %016lx\n",
	       regs->u_regs[12], regs->u_regs[13], regs->u_regs[14],
	       regs->u_regs[15]);
	printk("RPC: <%pS>\n", (void *) regs->u_regs[15]);
	show_regwindow(regs);
	show_stack(current, (unsigned long *) regs->u_regs[UREG_FP]);
}

struct global_reg_snapshot global_reg_snapshot[NR_CPUS];
static DEFINE_SPINLOCK(global_reg_snapshot_lock);

static void __global_reg_self(struct thread_info *tp, struct pt_regs *regs,
			      int this_cpu)
{
	flushw_all();

	global_reg_snapshot[this_cpu].tstate = regs->tstate;
	global_reg_snapshot[this_cpu].tpc = regs->tpc;
	global_reg_snapshot[this_cpu].tnpc = regs->tnpc;
	global_reg_snapshot[this_cpu].o7 = regs->u_regs[UREG_I7];

	if (regs->tstate & TSTATE_PRIV) {
		struct reg_window *rw;

		rw = (struct reg_window *)
			(regs->u_regs[UREG_FP] + STACK_BIAS);
		if (kstack_valid(tp, (unsigned long) rw)) {
			global_reg_snapshot[this_cpu].i7 = rw->ins[7];
			rw = (struct reg_window *)
				(rw->ins[6] + STACK_BIAS);
			if (kstack_valid(tp, (unsigned long) rw))
				global_reg_snapshot[this_cpu].rpc = rw->ins[7];
		}
	} else {
		global_reg_snapshot[this_cpu].i7 = 0;
		global_reg_snapshot[this_cpu].rpc = 0;
	}
	global_reg_snapshot[this_cpu].thread = tp;
}

/* In order to avoid hangs we do not try to synchronize with the
 * global register dump client cpus.  The last store they make is to
 * the thread pointer, so do a short poll waiting for that to become
 * non-NULL.
 */
static void __global_reg_poll(struct global_reg_snapshot *gp)
{
	int limit = 0;

	while (!gp->thread && ++limit < 100) {
		barrier();
		udelay(1);
	}
}

void arch_trigger_all_cpu_backtrace(void)
{
	struct thread_info *tp = current_thread_info();
	struct pt_regs *regs = get_irq_regs();
	unsigned long flags;
	int this_cpu, cpu;

	if (!regs)
		regs = tp->kregs;

	spin_lock_irqsave(&global_reg_snapshot_lock, flags);

	memset(global_reg_snapshot, 0, sizeof(global_reg_snapshot));

	this_cpu = raw_smp_processor_id();

	__global_reg_self(tp, regs, this_cpu);

	smp_fetch_global_regs();

	for_each_online_cpu(cpu) {
		struct global_reg_snapshot *gp = &global_reg_snapshot[cpu];

		__global_reg_poll(gp);

		tp = gp->thread;
		printk("%c CPU[%3d]: TSTATE[%016lx] TPC[%016lx] TNPC[%016lx] TASK[%s:%d]\n",
		       (cpu == this_cpu ? '*' : ' '), cpu,
		       gp->tstate, gp->tpc, gp->tnpc,
		       ((tp && tp->task) ? tp->task->comm : "NULL"),
		       ((tp && tp->task) ? tp->task->pid : -1));

		if (gp->tstate & TSTATE_PRIV) {
			printk("             TPC[%pS] O7[%pS] I7[%pS] RPC[%pS]\n",
			       (void *) gp->tpc,
			       (void *) gp->o7,
			       (void *) gp->i7,
			       (void *) gp->rpc);
		} else {
			printk("             TPC[%lx] O7[%lx] I7[%lx] RPC[%lx]\n",
			       gp->tpc, gp->o7, gp->i7, gp->rpc);
		}
	}

	memset(global_reg_snapshot, 0, sizeof(global_reg_snapshot));

	spin_unlock_irqrestore(&global_reg_snapshot_lock, flags);
}

#ifdef CONFIG_MAGIC_SYSRQ

static void sysrq_handle_globreg(int key)
{
	arch_trigger_all_cpu_backtrace();
}

static struct sysrq_key_op sparc_globalreg_op = {
	.handler	= sysrq_handle_globreg,
	.help_msg	= "Globalregs",
	.action_msg	= "Show Global CPU Regs",
};

static int __init sparc_globreg_init(void)
{
	return register_sysrq_key('y', &sparc_globalreg_op);
}

core_initcall(sparc_globreg_init);

#endif

unsigned long thread_saved_pc(struct task_struct *tsk)
{
	struct thread_info *ti = task_thread_info(tsk);
	unsigned long ret = 0xdeadbeefUL;
	
	if (ti && ti->ksp) {
		unsigned long *sp;
		sp = (unsigned long *)(ti->ksp + STACK_BIAS);
		if (((unsigned long)sp & (sizeof(long) - 1)) == 0UL &&
		    sp[14]) {
			unsigned long *fp;
			fp = (unsigned long *)(sp[14] + STACK_BIAS);
			if (((unsigned long)fp & (sizeof(long) - 1)) == 0UL)
				ret = fp[15];
		}
	}
	return ret;
}

/* Free current thread data structures etc.. */
void exit_thread(void)
{
	struct thread_info *t = current_thread_info();

	if (t->utraps) {
		if (t->utraps[0] < 2)
			kfree (t->utraps);
		else
			t->utraps[0]--;
	}
}

void flush_thread(void)
{
	struct thread_info *t = current_thread_info();
	struct mm_struct *mm;

	mm = t->task->mm;
	if (mm)
		tsb_context_switch(mm);

	set_thread_wsaved(0);

	/* Clear FPU register state. */
	t->fpsaved[0] = 0;
}

/* It's a bit more tricky when 64-bit tasks are involved... */
static unsigned long clone_stackframe(unsigned long csp, unsigned long psp)
{
	unsigned long fp, distance, rval;

	if (!(test_thread_flag(TIF_32BIT))) {
		csp += STACK_BIAS;
		psp += STACK_BIAS;
		__get_user(fp, &(((struct reg_window __user *)psp)->ins[6]));
		fp += STACK_BIAS;
	} else
		__get_user(fp, &(((struct reg_window32 __user *)psp)->ins[6]));

	/* Now align the stack as this is mandatory in the Sparc ABI
	 * due to how register windows work.  This hides the
	 * restriction from thread libraries etc.
	 */
	csp &= ~15UL;

	distance = fp - psp;
	rval = (csp - distance);
	if (copy_in_user((void __user *) rval, (void __user *) psp, distance))
		rval = 0;
	else if (test_thread_flag(TIF_32BIT)) {
		if (put_user(((u32)csp),
			     &(((struct reg_window32 __user *)rval)->ins[6])))
			rval = 0;
	} else {
		if (put_user(((u64)csp - STACK_BIAS),
			     &(((struct reg_window __user *)rval)->ins[6])))
			rval = 0;
		else
			rval = rval - STACK_BIAS;
	}

	return rval;
}

/* Standard stuff. */
static inline void shift_window_buffer(int first_win, int last_win,
				       struct thread_info *t)
{
	int i;

	for (i = first_win; i < last_win; i++) {
		t->rwbuf_stkptrs[i] = t->rwbuf_stkptrs[i+1];
		memcpy(&t->reg_window[i], &t->reg_window[i+1],
		       sizeof(struct reg_window));
	}
}

void synchronize_user_stack(void)
{
	struct thread_info *t = current_thread_info();
	unsigned long window;

	flush_user_windows();
	if ((window = get_thread_wsaved()) != 0) {
		int winsize = sizeof(struct reg_window);
		int bias = 0;

		if (test_thread_flag(TIF_32BIT))
			winsize = sizeof(struct reg_window32);
		else
			bias = STACK_BIAS;

		window -= 1;
		do {
			unsigned long sp = (t->rwbuf_stkptrs[window] + bias);
			struct reg_window *rwin = &t->reg_window[window];

			if (!copy_to_user((char __user *)sp, rwin, winsize)) {
				shift_window_buffer(window, get_thread_wsaved() - 1, t);
				set_thread_wsaved(get_thread_wsaved() - 1);
			}
		} while (window--);
	}
}

static void stack_unaligned(unsigned long sp)
{
	siginfo_t info;

	info.si_signo = SIGBUS;
	info.si_errno = 0;
	info.si_code = BUS_ADRALN;
	info.si_addr = (void __user *) sp;
	info.si_trapno = 0;
	force_sig_info(SIGBUS, &info, current);
}

void fault_in_user_windows(void)
{
	struct thread_info *t = current_thread_info();
	unsigned long window;
	int winsize = sizeof(struct reg_window);
	int bias = 0;

	if (test_thread_flag(TIF_32BIT))
		winsize = sizeof(struct reg_window32);
	else
		bias = STACK_BIAS;

	flush_user_windows();
	window = get_thread_wsaved();

	if (likely(window != 0)) {
		window -= 1;
		do {
			unsigned long sp = (t->rwbuf_stkptrs[window] + bias);
			struct reg_window *rwin = &t->reg_window[window];

			if (unlikely(sp & 0x7UL))
				stack_unaligned(sp);

			if (unlikely(copy_to_user((char __user *)sp,
						  rwin, winsize)))
				goto barf;
		} while (window--);
	}
	set_thread_wsaved(0);
	return;

barf:
	set_thread_wsaved(window + 1);
	do_exit(SIGILL);
}

asmlinkage long sparc_do_fork(unsigned long clone_flags,
			      unsigned long stack_start,
			      struct pt_regs *regs,
			      unsigned long stack_size)
{
	int __user *parent_tid_ptr, *child_tid_ptr;
	unsigned long orig_i1 = regs->u_regs[UREG_I1];
	long ret;

#ifdef CONFIG_COMPAT
	if (test_thread_flag(TIF_32BIT)) {
		parent_tid_ptr = compat_ptr(regs->u_regs[UREG_I2]);
		child_tid_ptr = compat_ptr(regs->u_regs[UREG_I4]);
	} else
#endif
	{
		parent_tid_ptr = (int __user *) regs->u_regs[UREG_I2];
		child_tid_ptr = (int __user *) regs->u_regs[UREG_I4];
	}

	ret = do_fork(clone_flags, stack_start,
		      regs, stack_size,
		      parent_tid_ptr, child_tid_ptr);

	/* If we get an error and potentially restart the system
	 * call, we're screwed because copy_thread() clobbered
	 * the parent's %o1.  So detect that case and restore it
	 * here.
	 */
	if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
		regs->u_regs[UREG_I1] = orig_i1;

	return ret;
}

/* Copy a Sparc thread.  The fork() return value conventions
 * under SunOS are nothing short of bletcherous:
 * Parent -->  %o0 == childs  pid, %o1 == 0
 * Child  -->  %o0 == parents pid, %o1 == 1
 */
int copy_thread(unsigned long clone_flags, unsigned long sp,
		unsigned long unused,
		struct task_struct *p, struct pt_regs *regs)
{
	struct thread_info *t = task_thread_info(p);
	struct sparc_stackf *parent_sf;
	unsigned long child_stack_sz;
	char *child_trap_frame;
	int kernel_thread;

	kernel_thread = (regs->tstate & TSTATE_PRIV) ? 1 : 0;
	parent_sf = ((struct sparc_stackf *) regs) - 1;

	/* Calculate offset to stack_frame & pt_regs */
	child_stack_sz = ((STACKFRAME_SZ + TRACEREG_SZ) +
			  (kernel_thread ? STACKFRAME_SZ : 0));
	child_trap_frame = (task_stack_page(p) +
			    (THREAD_SIZE - child_stack_sz));
	memcpy(child_trap_frame, parent_sf, child_stack_sz);

	t->flags = (t->flags & ~((0xffUL << TI_FLAG_CWP_SHIFT) |
				 (0xffUL << TI_FLAG_CURRENT_DS_SHIFT))) |
		(((regs->tstate + 1) & TSTATE_CWP) << TI_FLAG_CWP_SHIFT);
	t->new_child = 1;
	t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS;
	t->kregs = (struct pt_regs *) (child_trap_frame +
				       sizeof(struct sparc_stackf));
	t->fpsaved[0] = 0;

	if (kernel_thread) {
		struct sparc_stackf *child_sf = (struct sparc_stackf *)
			(child_trap_frame + (STACKFRAME_SZ + TRACEREG_SZ));

		/* Zero terminate the stack backtrace.  */
		child_sf->fp = NULL;
		t->kregs->u_regs[UREG_FP] =
		  ((unsigned long) child_sf) - STACK_BIAS;

		t->flags |= ((long)ASI_P << TI_FLAG_CURRENT_DS_SHIFT);
		t->kregs->u_regs[UREG_G6] = (unsigned long) t;
		t->kregs->u_regs[UREG_G4] = (unsigned long) t->task;
	} else {
		if (t->flags & _TIF_32BIT) {
			sp &= 0x00000000ffffffffUL;
			regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
		}
		t->kregs->u_regs[UREG_FP] = sp;
		t->flags |= ((long)ASI_AIUS << TI_FLAG_CURRENT_DS_SHIFT);
		if (sp != regs->u_regs[UREG_FP]) {
			unsigned long csp;

			csp = clone_stackframe(sp, regs->u_regs[UREG_FP]);
			if (!csp)
				return -EFAULT;
			t->kregs->u_regs[UREG_FP] = csp;
		}
		if (t->utraps)
			t->utraps[0]++;
	}

	/* Set the return value for the child. */
	t->kregs->u_regs[UREG_I0] = current->pid;
	t->kregs->u_regs[UREG_I1] = 1;

	/* Set the second return value for the parent. */
	regs->u_regs[UREG_I1] = 0;

	if (clone_flags & CLONE_SETTLS)
		t->kregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];

	return 0;
}

/*
 * This is the mechanism for creating a new kernel thread.
 *
 * NOTE! Only a kernel-only process(ie the swapper or direct descendants
 * who haven't done an "execve()") should use this: it will work within
 * a system call from a "real" process, but the process memory space will
 * not be freed until both the parent and the child have exited.
 */
pid_t kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
{
	long retval;

	/* If the parent runs before fn(arg) is called by the child,
	 * the input registers of this function can be clobbered.
	 * So we stash 'fn' and 'arg' into global registers which
	 * will not be modified by the parent.
	 */
	__asm__ __volatile__("mov %4, %%g2\n\t"	   /* Save FN into global */
			     "mov %5, %%g3\n\t"	   /* Save ARG into global */
			     "mov %1, %%g1\n\t"	   /* Clone syscall nr. */
			     "mov %2, %%o0\n\t"	   /* Clone flags. */
			     "mov 0, %%o1\n\t"	   /* usp arg == 0 */
			     "t 0x6d\n\t"	   /* Linux/Sparc clone(). */
			     "brz,a,pn %%o1, 1f\n\t" /* Parent, just return. */
			     " mov %%o0, %0\n\t"
			     "jmpl %%g2, %%o7\n\t"   /* Call the function. */
			     " mov %%g3, %%o0\n\t"   /* Set arg in delay. */
			     "mov %3, %%g1\n\t"
			     "t 0x6d\n\t"	   /* Linux/Sparc exit(). */
			     /* Notreached by child. */
			     "1:" :
			     "=r" (retval) :
			     "i" (__NR_clone), "r" (flags | CLONE_VM | CLONE_UNTRACED),
			     "i" (__NR_exit),  "r" (fn), "r" (arg) :
			     "g1", "g2", "g3", "o0", "o1", "memory", "cc");
	return retval;
}
EXPORT_SYMBOL(kernel_thread);

typedef struct {
	union {
		unsigned int	pr_regs[32];
		unsigned long	pr_dregs[16];
	} pr_fr;
	unsigned int __unused;
	unsigned int	pr_fsr;
	unsigned char	pr_qcnt;
	unsigned char	pr_q_entrysize;
	unsigned char	pr_en;
	unsigned int	pr_q[64];
} elf_fpregset_t32;

/*
 * fill in the fpu structure for a core dump.
 */
int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
{
	unsigned long *kfpregs = current_thread_info()->fpregs;
	unsigned long fprs = current_thread_info()->fpsaved[0];

	if (test_thread_flag(TIF_32BIT)) {
		elf_fpregset_t32 *fpregs32 = (elf_fpregset_t32 *)fpregs;

		if (fprs & FPRS_DL)
			memcpy(&fpregs32->pr_fr.pr_regs[0], kfpregs,
			       sizeof(unsigned int) * 32);
		else
			memset(&fpregs32->pr_fr.pr_regs[0], 0,
			       sizeof(unsigned int) * 32);
		fpregs32->pr_qcnt = 0;
		fpregs32->pr_q_entrysize = 8;
		memset(&fpregs32->pr_q[0], 0,
		       (sizeof(unsigned int) * 64));
		if (fprs & FPRS_FEF) {
			fpregs32->pr_fsr = (unsigned int) current_thread_info()->xfsr[0];
			fpregs32->pr_en = 1;
		} else {
			fpregs32->pr_fsr = 0;
			fpregs32->pr_en = 0;
		}
	} else {
		if(fprs & FPRS_DL)
			memcpy(&fpregs->pr_regs[0], kfpregs,
			       sizeof(unsigned int) * 32);
		else
			memset(&fpregs->pr_regs[0], 0,
			       sizeof(unsigned int) * 32);
		if(fprs & FPRS_DU)
			memcpy(&fpregs->pr_regs[16], kfpregs+16,
			       sizeof(unsigned int) * 32);
		else
			memset(&fpregs->pr_regs[16], 0,
			       sizeof(unsigned int) * 32);
		if(fprs & FPRS_FEF) {
			fpregs->pr_fsr = current_thread_info()->xfsr[0];
			fpregs->pr_gsr = current_thread_info()->gsr[0];
		} else {
			fpregs->pr_fsr = fpregs->pr_gsr = 0;
		}
		fpregs->pr_fprs = fprs;
	}
	return 1;
}
EXPORT_SYMBOL(dump_fpu);

/*
 * sparc_execve() executes a new program after the asm stub has set
 * things up for us.  This should basically do what I want it to.
 */
asmlinkage int sparc_execve(struct pt_regs *regs)
{
	int error, base = 0;
	char *filename;

	/* User register window flush is done by entry.S */

	/* Check for indirect call. */
	if (regs->u_regs[UREG_G1] == 0)
		base = 1;

	filename = getname((char __user *)regs->u_regs[base + UREG_I0]);
	error = PTR_ERR(filename);
	if (IS_ERR(filename))
		goto out;
	error = do_execve(filename,
			  (const char __user *const __user *)
			  regs->u_regs[base + UREG_I1],
			  (const char __user *const __user *)
			  regs->u_regs[base + UREG_I2], regs);
	putname(filename);
	if (!error) {
		fprs_write(0);
		current_thread_info()->xfsr[0] = 0;
		current_thread_info()->fpsaved[0] = 0;
		regs->tstate &= ~TSTATE_PEF;
	}
out:
	return error;
}

unsigned long get_wchan(struct task_struct *task)
{
	unsigned long pc, fp, bias = 0;
	struct thread_info *tp;
	struct reg_window *rw;
        unsigned long ret = 0;
	int count = 0; 

	if (!task || task == current ||
            task->state == TASK_RUNNING)
		goto out;

	tp = task_thread_info(task);
	bias = STACK_BIAS;
	fp = task_thread_info(task)->ksp + bias;

	do {
		if (!kstack_valid(tp, fp))
			break;
		rw = (struct reg_window *) fp;
		pc = rw->ins[7];
		if (!in_sched_functions(pc)) {
			ret = pc;
			goto out;
		}
		fp = rw->ins[6] + bias;
	} while (++count < 16);

out:
	return ret;
}