xref: /linux/arch/sparc/kernel/process_64.c (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732)
1 /*  arch/sparc64/kernel/process.c
2  *
3  *  Copyright (C) 1995, 1996, 2008 David S. Miller (davem@davemloft.net)
4  *  Copyright (C) 1996       Eddie C. Dost   (ecd@skynet.be)
5  *  Copyright (C) 1997, 1998 Jakub Jelinek   (jj@sunsite.mff.cuni.cz)
6  */
7 
8 /*
9  * This file handles the architecture-dependent parts of process handling..
10  */
11 
12 #include <stdarg.h>
13 
14 #include <linux/errno.h>
15 #include <linux/export.h>
16 #include <linux/sched.h>
17 #include <linux/kernel.h>
18 #include <linux/mm.h>
19 #include <linux/fs.h>
20 #include <linux/smp.h>
21 #include <linux/stddef.h>
22 #include <linux/ptrace.h>
23 #include <linux/slab.h>
24 #include <linux/user.h>
25 #include <linux/delay.h>
26 #include <linux/compat.h>
27 #include <linux/tick.h>
28 #include <linux/init.h>
29 #include <linux/cpu.h>
30 #include <linux/perf_event.h>
31 #include <linux/elfcore.h>
32 #include <linux/sysrq.h>
33 #include <linux/nmi.h>
34 #include <linux/context_tracking.h>
35 
36 #include <asm/uaccess.h>
37 #include <asm/page.h>
38 #include <asm/pgalloc.h>
39 #include <asm/pgtable.h>
40 #include <asm/processor.h>
41 #include <asm/pstate.h>
42 #include <asm/elf.h>
43 #include <asm/fpumacro.h>
44 #include <asm/head.h>
45 #include <asm/cpudata.h>
46 #include <asm/mmu_context.h>
47 #include <asm/unistd.h>
48 #include <asm/hypervisor.h>
49 #include <asm/syscalls.h>
50 #include <asm/irq_regs.h>
51 #include <asm/smp.h>
52 #include <asm/pcr.h>
53 
54 #include "kstack.h"
55 
56 /* Idle loop support on sparc64. */
57 void arch_cpu_idle(void)
58 {
59 	if (tlb_type != hypervisor) {
60 		touch_nmi_watchdog();
61 		local_irq_enable();
62 	} else {
63 		unsigned long pstate;
64 
65 		local_irq_enable();
66 
67                 /* The sun4v sleeping code requires that we have PSTATE.IE cleared over
68                  * the cpu sleep hypervisor call.
69                  */
70 		__asm__ __volatile__(
71 			"rdpr %%pstate, %0\n\t"
72 			"andn %0, %1, %0\n\t"
73 			"wrpr %0, %%g0, %%pstate"
74 			: "=&r" (pstate)
75 			: "i" (PSTATE_IE));
76 
77 		if (!need_resched() && !cpu_is_offline(smp_processor_id()))
78 			sun4v_cpu_yield();
79 
80 		/* Re-enable interrupts. */
81 		__asm__ __volatile__(
82 			"rdpr %%pstate, %0\n\t"
83 			"or %0, %1, %0\n\t"
84 			"wrpr %0, %%g0, %%pstate"
85 			: "=&r" (pstate)
86 			: "i" (PSTATE_IE));
87 	}
88 }
89 
90 #ifdef CONFIG_HOTPLUG_CPU
91 void arch_cpu_idle_dead(void)
92 {
93 	sched_preempt_enable_no_resched();
94 	cpu_play_dead();
95 }
96 #endif
97 
98 #ifdef CONFIG_COMPAT
99 static void show_regwindow32(struct pt_regs *regs)
100 {
101 	struct reg_window32 __user *rw;
102 	struct reg_window32 r_w;
103 	mm_segment_t old_fs;
104 
105 	__asm__ __volatile__ ("flushw");
106 	rw = compat_ptr((unsigned)regs->u_regs[14]);
107 	old_fs = get_fs();
108 	set_fs (USER_DS);
109 	if (copy_from_user (&r_w, rw, sizeof(r_w))) {
110 		set_fs (old_fs);
111 		return;
112 	}
113 
114 	set_fs (old_fs);
115 	printk("l0: %08x l1: %08x l2: %08x l3: %08x "
116 	       "l4: %08x l5: %08x l6: %08x l7: %08x\n",
117 	       r_w.locals[0], r_w.locals[1], r_w.locals[2], r_w.locals[3],
118 	       r_w.locals[4], r_w.locals[5], r_w.locals[6], r_w.locals[7]);
119 	printk("i0: %08x i1: %08x i2: %08x i3: %08x "
120 	       "i4: %08x i5: %08x i6: %08x i7: %08x\n",
121 	       r_w.ins[0], r_w.ins[1], r_w.ins[2], r_w.ins[3],
122 	       r_w.ins[4], r_w.ins[5], r_w.ins[6], r_w.ins[7]);
123 }
124 #else
125 #define show_regwindow32(regs)	do { } while (0)
126 #endif
127 
128 static void show_regwindow(struct pt_regs *regs)
129 {
130 	struct reg_window __user *rw;
131 	struct reg_window *rwk;
132 	struct reg_window r_w;
133 	mm_segment_t old_fs;
134 
135 	if ((regs->tstate & TSTATE_PRIV) || !(test_thread_flag(TIF_32BIT))) {
136 		__asm__ __volatile__ ("flushw");
137 		rw = (struct reg_window __user *)
138 			(regs->u_regs[14] + STACK_BIAS);
139 		rwk = (struct reg_window *)
140 			(regs->u_regs[14] + STACK_BIAS);
141 		if (!(regs->tstate & TSTATE_PRIV)) {
142 			old_fs = get_fs();
143 			set_fs (USER_DS);
144 			if (copy_from_user (&r_w, rw, sizeof(r_w))) {
145 				set_fs (old_fs);
146 				return;
147 			}
148 			rwk = &r_w;
149 			set_fs (old_fs);
150 		}
151 	} else {
152 		show_regwindow32(regs);
153 		return;
154 	}
155 	printk("l0: %016lx l1: %016lx l2: %016lx l3: %016lx\n",
156 	       rwk->locals[0], rwk->locals[1], rwk->locals[2], rwk->locals[3]);
157 	printk("l4: %016lx l5: %016lx l6: %016lx l7: %016lx\n",
158 	       rwk->locals[4], rwk->locals[5], rwk->locals[6], rwk->locals[7]);
159 	printk("i0: %016lx i1: %016lx i2: %016lx i3: %016lx\n",
160 	       rwk->ins[0], rwk->ins[1], rwk->ins[2], rwk->ins[3]);
161 	printk("i4: %016lx i5: %016lx i6: %016lx i7: %016lx\n",
162 	       rwk->ins[4], rwk->ins[5], rwk->ins[6], rwk->ins[7]);
163 	if (regs->tstate & TSTATE_PRIV)
164 		printk("I7: <%pS>\n", (void *) rwk->ins[7]);
165 }
166 
167 void show_regs(struct pt_regs *regs)
168 {
169 	show_regs_print_info(KERN_DEFAULT);
170 
171 	printk("TSTATE: %016lx TPC: %016lx TNPC: %016lx Y: %08x    %s\n", regs->tstate,
172 	       regs->tpc, regs->tnpc, regs->y, print_tainted());
173 	printk("TPC: <%pS>\n", (void *) regs->tpc);
174 	printk("g0: %016lx g1: %016lx g2: %016lx g3: %016lx\n",
175 	       regs->u_regs[0], regs->u_regs[1], regs->u_regs[2],
176 	       regs->u_regs[3]);
177 	printk("g4: %016lx g5: %016lx g6: %016lx g7: %016lx\n",
178 	       regs->u_regs[4], regs->u_regs[5], regs->u_regs[6],
179 	       regs->u_regs[7]);
180 	printk("o0: %016lx o1: %016lx o2: %016lx o3: %016lx\n",
181 	       regs->u_regs[8], regs->u_regs[9], regs->u_regs[10],
182 	       regs->u_regs[11]);
183 	printk("o4: %016lx o5: %016lx sp: %016lx ret_pc: %016lx\n",
184 	       regs->u_regs[12], regs->u_regs[13], regs->u_regs[14],
185 	       regs->u_regs[15]);
186 	printk("RPC: <%pS>\n", (void *) regs->u_regs[15]);
187 	show_regwindow(regs);
188 	show_stack(current, (unsigned long *) regs->u_regs[UREG_FP]);
189 }
190 
191 union global_cpu_snapshot global_cpu_snapshot[NR_CPUS];
192 static DEFINE_SPINLOCK(global_cpu_snapshot_lock);
193 
194 static void __global_reg_self(struct thread_info *tp, struct pt_regs *regs,
195 			      int this_cpu)
196 {
197 	struct global_reg_snapshot *rp;
198 
199 	flushw_all();
200 
201 	rp = &global_cpu_snapshot[this_cpu].reg;
202 
203 	rp->tstate = regs->tstate;
204 	rp->tpc = regs->tpc;
205 	rp->tnpc = regs->tnpc;
206 	rp->o7 = regs->u_regs[UREG_I7];
207 
208 	if (regs->tstate & TSTATE_PRIV) {
209 		struct reg_window *rw;
210 
211 		rw = (struct reg_window *)
212 			(regs->u_regs[UREG_FP] + STACK_BIAS);
213 		if (kstack_valid(tp, (unsigned long) rw)) {
214 			rp->i7 = rw->ins[7];
215 			rw = (struct reg_window *)
216 				(rw->ins[6] + STACK_BIAS);
217 			if (kstack_valid(tp, (unsigned long) rw))
218 				rp->rpc = rw->ins[7];
219 		}
220 	} else {
221 		rp->i7 = 0;
222 		rp->rpc = 0;
223 	}
224 	rp->thread = tp;
225 }
226 
227 /* In order to avoid hangs we do not try to synchronize with the
228  * global register dump client cpus.  The last store they make is to
229  * the thread pointer, so do a short poll waiting for that to become
230  * non-NULL.
231  */
232 static void __global_reg_poll(struct global_reg_snapshot *gp)
233 {
234 	int limit = 0;
235 
236 	while (!gp->thread && ++limit < 100) {
237 		barrier();
238 		udelay(1);
239 	}
240 }
241 
242 void arch_trigger_all_cpu_backtrace(bool include_self)
243 {
244 	struct thread_info *tp = current_thread_info();
245 	struct pt_regs *regs = get_irq_regs();
246 	unsigned long flags;
247 	int this_cpu, cpu;
248 
249 	if (!regs)
250 		regs = tp->kregs;
251 
252 	spin_lock_irqsave(&global_cpu_snapshot_lock, flags);
253 
254 	this_cpu = raw_smp_processor_id();
255 
256 	memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
257 
258 	if (include_self)
259 		__global_reg_self(tp, regs, this_cpu);
260 
261 	smp_fetch_global_regs();
262 
263 	for_each_online_cpu(cpu) {
264 		struct global_reg_snapshot *gp;
265 
266 		if (!include_self && cpu == this_cpu)
267 			continue;
268 
269 		gp = &global_cpu_snapshot[cpu].reg;
270 
271 		__global_reg_poll(gp);
272 
273 		tp = gp->thread;
274 		printk("%c CPU[%3d]: TSTATE[%016lx] TPC[%016lx] TNPC[%016lx] TASK[%s:%d]\n",
275 		       (cpu == this_cpu ? '*' : ' '), cpu,
276 		       gp->tstate, gp->tpc, gp->tnpc,
277 		       ((tp && tp->task) ? tp->task->comm : "NULL"),
278 		       ((tp && tp->task) ? tp->task->pid : -1));
279 
280 		if (gp->tstate & TSTATE_PRIV) {
281 			printk("             TPC[%pS] O7[%pS] I7[%pS] RPC[%pS]\n",
282 			       (void *) gp->tpc,
283 			       (void *) gp->o7,
284 			       (void *) gp->i7,
285 			       (void *) gp->rpc);
286 		} else {
287 			printk("             TPC[%lx] O7[%lx] I7[%lx] RPC[%lx]\n",
288 			       gp->tpc, gp->o7, gp->i7, gp->rpc);
289 		}
290 
291 		touch_nmi_watchdog();
292 	}
293 
294 	memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
295 
296 	spin_unlock_irqrestore(&global_cpu_snapshot_lock, flags);
297 }
298 
299 #ifdef CONFIG_MAGIC_SYSRQ
300 
301 static void sysrq_handle_globreg(int key)
302 {
303 	arch_trigger_all_cpu_backtrace(true);
304 }
305 
306 static struct sysrq_key_op sparc_globalreg_op = {
307 	.handler	= sysrq_handle_globreg,
308 	.help_msg	= "global-regs(y)",
309 	.action_msg	= "Show Global CPU Regs",
310 };
311 
312 static void __global_pmu_self(int this_cpu)
313 {
314 	struct global_pmu_snapshot *pp;
315 	int i, num;
316 
317 	if (!pcr_ops)
318 		return;
319 
320 	pp = &global_cpu_snapshot[this_cpu].pmu;
321 
322 	num = 1;
323 	if (tlb_type == hypervisor &&
324 	    sun4v_chip_type >= SUN4V_CHIP_NIAGARA4)
325 		num = 4;
326 
327 	for (i = 0; i < num; i++) {
328 		pp->pcr[i] = pcr_ops->read_pcr(i);
329 		pp->pic[i] = pcr_ops->read_pic(i);
330 	}
331 }
332 
333 static void __global_pmu_poll(struct global_pmu_snapshot *pp)
334 {
335 	int limit = 0;
336 
337 	while (!pp->pcr[0] && ++limit < 100) {
338 		barrier();
339 		udelay(1);
340 	}
341 }
342 
343 static void pmu_snapshot_all_cpus(void)
344 {
345 	unsigned long flags;
346 	int this_cpu, cpu;
347 
348 	spin_lock_irqsave(&global_cpu_snapshot_lock, flags);
349 
350 	memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
351 
352 	this_cpu = raw_smp_processor_id();
353 
354 	__global_pmu_self(this_cpu);
355 
356 	smp_fetch_global_pmu();
357 
358 	for_each_online_cpu(cpu) {
359 		struct global_pmu_snapshot *pp = &global_cpu_snapshot[cpu].pmu;
360 
361 		__global_pmu_poll(pp);
362 
363 		printk("%c CPU[%3d]: PCR[%08lx:%08lx:%08lx:%08lx] PIC[%08lx:%08lx:%08lx:%08lx]\n",
364 		       (cpu == this_cpu ? '*' : ' '), cpu,
365 		       pp->pcr[0], pp->pcr[1], pp->pcr[2], pp->pcr[3],
366 		       pp->pic[0], pp->pic[1], pp->pic[2], pp->pic[3]);
367 
368 		touch_nmi_watchdog();
369 	}
370 
371 	memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
372 
373 	spin_unlock_irqrestore(&global_cpu_snapshot_lock, flags);
374 }
375 
376 static void sysrq_handle_globpmu(int key)
377 {
378 	pmu_snapshot_all_cpus();
379 }
380 
381 static struct sysrq_key_op sparc_globalpmu_op = {
382 	.handler	= sysrq_handle_globpmu,
383 	.help_msg	= "global-pmu(x)",
384 	.action_msg	= "Show Global PMU Regs",
385 };
386 
387 static int __init sparc_sysrq_init(void)
388 {
389 	int ret = register_sysrq_key('y', &sparc_globalreg_op);
390 
391 	if (!ret)
392 		ret = register_sysrq_key('x', &sparc_globalpmu_op);
393 	return ret;
394 }
395 
396 core_initcall(sparc_sysrq_init);
397 
398 #endif
399 
400 unsigned long thread_saved_pc(struct task_struct *tsk)
401 {
402 	struct thread_info *ti = task_thread_info(tsk);
403 	unsigned long ret = 0xdeadbeefUL;
404 
405 	if (ti && ti->ksp) {
406 		unsigned long *sp;
407 		sp = (unsigned long *)(ti->ksp + STACK_BIAS);
408 		if (((unsigned long)sp & (sizeof(long) - 1)) == 0UL &&
409 		    sp[14]) {
410 			unsigned long *fp;
411 			fp = (unsigned long *)(sp[14] + STACK_BIAS);
412 			if (((unsigned long)fp & (sizeof(long) - 1)) == 0UL)
413 				ret = fp[15];
414 		}
415 	}
416 	return ret;
417 }
418 
419 /* Free current thread data structures etc.. */
420 void exit_thread(void)
421 {
422 	struct thread_info *t = current_thread_info();
423 
424 	if (t->utraps) {
425 		if (t->utraps[0] < 2)
426 			kfree (t->utraps);
427 		else
428 			t->utraps[0]--;
429 	}
430 }
431 
432 void flush_thread(void)
433 {
434 	struct thread_info *t = current_thread_info();
435 	struct mm_struct *mm;
436 
437 	mm = t->task->mm;
438 	if (mm)
439 		tsb_context_switch(mm);
440 
441 	set_thread_wsaved(0);
442 
443 	/* Clear FPU register state. */
444 	t->fpsaved[0] = 0;
445 }
446 
447 /* It's a bit more tricky when 64-bit tasks are involved... */
448 static unsigned long clone_stackframe(unsigned long csp, unsigned long psp)
449 {
450 	bool stack_64bit = test_thread_64bit_stack(psp);
451 	unsigned long fp, distance, rval;
452 
453 	if (stack_64bit) {
454 		csp += STACK_BIAS;
455 		psp += STACK_BIAS;
456 		__get_user(fp, &(((struct reg_window __user *)psp)->ins[6]));
457 		fp += STACK_BIAS;
458 		if (test_thread_flag(TIF_32BIT))
459 			fp &= 0xffffffff;
460 	} else
461 		__get_user(fp, &(((struct reg_window32 __user *)psp)->ins[6]));
462 
463 	/* Now align the stack as this is mandatory in the Sparc ABI
464 	 * due to how register windows work.  This hides the
465 	 * restriction from thread libraries etc.
466 	 */
467 	csp &= ~15UL;
468 
469 	distance = fp - psp;
470 	rval = (csp - distance);
471 	if (copy_in_user((void __user *) rval, (void __user *) psp, distance))
472 		rval = 0;
473 	else if (!stack_64bit) {
474 		if (put_user(((u32)csp),
475 			     &(((struct reg_window32 __user *)rval)->ins[6])))
476 			rval = 0;
477 	} else {
478 		if (put_user(((u64)csp - STACK_BIAS),
479 			     &(((struct reg_window __user *)rval)->ins[6])))
480 			rval = 0;
481 		else
482 			rval = rval - STACK_BIAS;
483 	}
484 
485 	return rval;
486 }
487 
488 /* Standard stuff. */
489 static inline void shift_window_buffer(int first_win, int last_win,
490 				       struct thread_info *t)
491 {
492 	int i;
493 
494 	for (i = first_win; i < last_win; i++) {
495 		t->rwbuf_stkptrs[i] = t->rwbuf_stkptrs[i+1];
496 		memcpy(&t->reg_window[i], &t->reg_window[i+1],
497 		       sizeof(struct reg_window));
498 	}
499 }
500 
501 void synchronize_user_stack(void)
502 {
503 	struct thread_info *t = current_thread_info();
504 	unsigned long window;
505 
506 	flush_user_windows();
507 	if ((window = get_thread_wsaved()) != 0) {
508 		window -= 1;
509 		do {
510 			struct reg_window *rwin = &t->reg_window[window];
511 			int winsize = sizeof(struct reg_window);
512 			unsigned long sp;
513 
514 			sp = t->rwbuf_stkptrs[window];
515 
516 			if (test_thread_64bit_stack(sp))
517 				sp += STACK_BIAS;
518 			else
519 				winsize = sizeof(struct reg_window32);
520 
521 			if (!copy_to_user((char __user *)sp, rwin, winsize)) {
522 				shift_window_buffer(window, get_thread_wsaved() - 1, t);
523 				set_thread_wsaved(get_thread_wsaved() - 1);
524 			}
525 		} while (window--);
526 	}
527 }
528 
529 static void stack_unaligned(unsigned long sp)
530 {
531 	siginfo_t info;
532 
533 	info.si_signo = SIGBUS;
534 	info.si_errno = 0;
535 	info.si_code = BUS_ADRALN;
536 	info.si_addr = (void __user *) sp;
537 	info.si_trapno = 0;
538 	force_sig_info(SIGBUS, &info, current);
539 }
540 
541 void fault_in_user_windows(void)
542 {
543 	struct thread_info *t = current_thread_info();
544 	unsigned long window;
545 
546 	flush_user_windows();
547 	window = get_thread_wsaved();
548 
549 	if (likely(window != 0)) {
550 		window -= 1;
551 		do {
552 			struct reg_window *rwin = &t->reg_window[window];
553 			int winsize = sizeof(struct reg_window);
554 			unsigned long sp;
555 
556 			sp = t->rwbuf_stkptrs[window];
557 
558 			if (test_thread_64bit_stack(sp))
559 				sp += STACK_BIAS;
560 			else
561 				winsize = sizeof(struct reg_window32);
562 
563 			if (unlikely(sp & 0x7UL))
564 				stack_unaligned(sp);
565 
566 			if (unlikely(copy_to_user((char __user *)sp,
567 						  rwin, winsize)))
568 				goto barf;
569 		} while (window--);
570 	}
571 	set_thread_wsaved(0);
572 	return;
573 
574 barf:
575 	set_thread_wsaved(window + 1);
576 	user_exit();
577 	do_exit(SIGILL);
578 }
579 
580 asmlinkage long sparc_do_fork(unsigned long clone_flags,
581 			      unsigned long stack_start,
582 			      struct pt_regs *regs,
583 			      unsigned long stack_size)
584 {
585 	int __user *parent_tid_ptr, *child_tid_ptr;
586 	unsigned long orig_i1 = regs->u_regs[UREG_I1];
587 	long ret;
588 
589 #ifdef CONFIG_COMPAT
590 	if (test_thread_flag(TIF_32BIT)) {
591 		parent_tid_ptr = compat_ptr(regs->u_regs[UREG_I2]);
592 		child_tid_ptr = compat_ptr(regs->u_regs[UREG_I4]);
593 	} else
594 #endif
595 	{
596 		parent_tid_ptr = (int __user *) regs->u_regs[UREG_I2];
597 		child_tid_ptr = (int __user *) regs->u_regs[UREG_I4];
598 	}
599 
600 	ret = do_fork(clone_flags, stack_start, stack_size,
601 		      parent_tid_ptr, child_tid_ptr);
602 
603 	/* If we get an error and potentially restart the system
604 	 * call, we're screwed because copy_thread() clobbered
605 	 * the parent's %o1.  So detect that case and restore it
606 	 * here.
607 	 */
608 	if ((unsigned long)ret >= -ERESTART_RESTARTBLOCK)
609 		regs->u_regs[UREG_I1] = orig_i1;
610 
611 	return ret;
612 }
613 
614 /* Copy a Sparc thread.  The fork() return value conventions
615  * under SunOS are nothing short of bletcherous:
616  * Parent -->  %o0 == childs  pid, %o1 == 0
617  * Child  -->  %o0 == parents pid, %o1 == 1
618  */
619 int copy_thread(unsigned long clone_flags, unsigned long sp,
620 		unsigned long arg, struct task_struct *p)
621 {
622 	struct thread_info *t = task_thread_info(p);
623 	struct pt_regs *regs = current_pt_regs();
624 	struct sparc_stackf *parent_sf;
625 	unsigned long child_stack_sz;
626 	char *child_trap_frame;
627 
628 	/* Calculate offset to stack_frame & pt_regs */
629 	child_stack_sz = (STACKFRAME_SZ + TRACEREG_SZ);
630 	child_trap_frame = (task_stack_page(p) +
631 			    (THREAD_SIZE - child_stack_sz));
632 
633 	t->new_child = 1;
634 	t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS;
635 	t->kregs = (struct pt_regs *) (child_trap_frame +
636 				       sizeof(struct sparc_stackf));
637 	t->fpsaved[0] = 0;
638 
639 	if (unlikely(p->flags & PF_KTHREAD)) {
640 		memset(child_trap_frame, 0, child_stack_sz);
641 		__thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] =
642 			(current_pt_regs()->tstate + 1) & TSTATE_CWP;
643 		t->current_ds = ASI_P;
644 		t->kregs->u_regs[UREG_G1] = sp; /* function */
645 		t->kregs->u_regs[UREG_G2] = arg;
646 		return 0;
647 	}
648 
649 	parent_sf = ((struct sparc_stackf *) regs) - 1;
650 	memcpy(child_trap_frame, parent_sf, child_stack_sz);
651 	if (t->flags & _TIF_32BIT) {
652 		sp &= 0x00000000ffffffffUL;
653 		regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
654 	}
655 	t->kregs->u_regs[UREG_FP] = sp;
656 	__thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] =
657 		(regs->tstate + 1) & TSTATE_CWP;
658 	t->current_ds = ASI_AIUS;
659 	if (sp != regs->u_regs[UREG_FP]) {
660 		unsigned long csp;
661 
662 		csp = clone_stackframe(sp, regs->u_regs[UREG_FP]);
663 		if (!csp)
664 			return -EFAULT;
665 		t->kregs->u_regs[UREG_FP] = csp;
666 	}
667 	if (t->utraps)
668 		t->utraps[0]++;
669 
670 	/* Set the return value for the child. */
671 	t->kregs->u_regs[UREG_I0] = current->pid;
672 	t->kregs->u_regs[UREG_I1] = 1;
673 
674 	/* Set the second return value for the parent. */
675 	regs->u_regs[UREG_I1] = 0;
676 
677 	if (clone_flags & CLONE_SETTLS)
678 		t->kregs->u_regs[UREG_G7] = regs->u_regs[UREG_I3];
679 
680 	return 0;
681 }
682 
683 typedef struct {
684 	union {
685 		unsigned int	pr_regs[32];
686 		unsigned long	pr_dregs[16];
687 	} pr_fr;
688 	unsigned int __unused;
689 	unsigned int	pr_fsr;
690 	unsigned char	pr_qcnt;
691 	unsigned char	pr_q_entrysize;
692 	unsigned char	pr_en;
693 	unsigned int	pr_q[64];
694 } elf_fpregset_t32;
695 
696 /*
697  * fill in the fpu structure for a core dump.
698  */
699 int dump_fpu (struct pt_regs * regs, elf_fpregset_t * fpregs)
700 {
701 	unsigned long *kfpregs = current_thread_info()->fpregs;
702 	unsigned long fprs = current_thread_info()->fpsaved[0];
703 
704 	if (test_thread_flag(TIF_32BIT)) {
705 		elf_fpregset_t32 *fpregs32 = (elf_fpregset_t32 *)fpregs;
706 
707 		if (fprs & FPRS_DL)
708 			memcpy(&fpregs32->pr_fr.pr_regs[0], kfpregs,
709 			       sizeof(unsigned int) * 32);
710 		else
711 			memset(&fpregs32->pr_fr.pr_regs[0], 0,
712 			       sizeof(unsigned int) * 32);
713 		fpregs32->pr_qcnt = 0;
714 		fpregs32->pr_q_entrysize = 8;
715 		memset(&fpregs32->pr_q[0], 0,
716 		       (sizeof(unsigned int) * 64));
717 		if (fprs & FPRS_FEF) {
718 			fpregs32->pr_fsr = (unsigned int) current_thread_info()->xfsr[0];
719 			fpregs32->pr_en = 1;
720 		} else {
721 			fpregs32->pr_fsr = 0;
722 			fpregs32->pr_en = 0;
723 		}
724 	} else {
725 		if(fprs & FPRS_DL)
726 			memcpy(&fpregs->pr_regs[0], kfpregs,
727 			       sizeof(unsigned int) * 32);
728 		else
729 			memset(&fpregs->pr_regs[0], 0,
730 			       sizeof(unsigned int) * 32);
731 		if(fprs & FPRS_DU)
732 			memcpy(&fpregs->pr_regs[16], kfpregs+16,
733 			       sizeof(unsigned int) * 32);
734 		else
735 			memset(&fpregs->pr_regs[16], 0,
736 			       sizeof(unsigned int) * 32);
737 		if(fprs & FPRS_FEF) {
738 			fpregs->pr_fsr = current_thread_info()->xfsr[0];
739 			fpregs->pr_gsr = current_thread_info()->gsr[0];
740 		} else {
741 			fpregs->pr_fsr = fpregs->pr_gsr = 0;
742 		}
743 		fpregs->pr_fprs = fprs;
744 	}
745 	return 1;
746 }
747 EXPORT_SYMBOL(dump_fpu);
748 
749 unsigned long get_wchan(struct task_struct *task)
750 {
751 	unsigned long pc, fp, bias = 0;
752 	struct thread_info *tp;
753 	struct reg_window *rw;
754         unsigned long ret = 0;
755 	int count = 0;
756 
757 	if (!task || task == current ||
758             task->state == TASK_RUNNING)
759 		goto out;
760 
761 	tp = task_thread_info(task);
762 	bias = STACK_BIAS;
763 	fp = task_thread_info(task)->ksp + bias;
764 
765 	do {
766 		if (!kstack_valid(tp, fp))
767 			break;
768 		rw = (struct reg_window *) fp;
769 		pc = rw->ins[7];
770 		if (!in_sched_functions(pc)) {
771 			ret = pc;
772 			goto out;
773 		}
774 		fp = rw->ins[6] + bias;
775 	} while (++count < 16);
776 
777 out:
778 	return ret;
779 }
780