xref: /openbmc/linux/arch/sparc/kernel/process_64.c (revision 5224f790) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*  arch/sparc64/kernel/process.c
3  *
4  *  Copyright (C) 1995, 1996, 2008 David S. Miller (davem@davemloft.net)
5  *  Copyright (C) 1996       Eddie C. Dost   (ecd@skynet.be)
6  *  Copyright (C) 1997, 1998 Jakub Jelinek   (jj@sunsite.mff.cuni.cz)
7  */
8 
9 /*
10  * This file handles the architecture-dependent parts of process handling..
11  */
12 #include <linux/errno.h>
13 #include <linux/export.h>
14 #include <linux/sched.h>
15 #include <linux/sched/debug.h>
16 #include <linux/sched/task.h>
17 #include <linux/sched/task_stack.h>
18 #include <linux/kernel.h>
19 #include <linux/mm.h>
20 #include <linux/fs.h>
21 #include <linux/smp.h>
22 #include <linux/stddef.h>
23 #include <linux/ptrace.h>
24 #include <linux/slab.h>
25 #include <linux/user.h>
26 #include <linux/delay.h>
27 #include <linux/compat.h>
28 #include <linux/tick.h>
29 #include <linux/init.h>
30 #include <linux/cpu.h>
31 #include <linux/perf_event.h>
32 #include <linux/elfcore.h>
33 #include <linux/sysrq.h>
34 #include <linux/nmi.h>
35 #include <linux/context_tracking.h>
36 #include <linux/signal.h>
37 
38 #include <linux/uaccess.h>
39 #include <asm/page.h>
40 #include <asm/pgalloc.h>
41 #include <asm/processor.h>
42 #include <asm/pstate.h>
43 #include <asm/elf.h>
44 #include <asm/fpumacro.h>
45 #include <asm/head.h>
46 #include <asm/cpudata.h>
47 #include <asm/mmu_context.h>
48 #include <asm/unistd.h>
49 #include <asm/hypervisor.h>
50 #include <asm/syscalls.h>
51 #include <asm/irq_regs.h>
52 #include <asm/smp.h>
53 #include <asm/pcr.h>
54 
55 #include "kstack.h"
56 
57 /* Idle loop support on sparc64. */
58 void arch_cpu_idle(void)
59 {
60 	if (tlb_type != hypervisor) {
61 		touch_nmi_watchdog();
62 		raw_local_irq_enable();
63 	} else {
64 		unsigned long pstate;
65 
66 		raw_local_irq_enable();
67 
68                 /* The sun4v sleeping code requires that we have PSTATE.IE cleared over
69                  * the cpu sleep hypervisor call.
70                  */
71 		__asm__ __volatile__(
72 			"rdpr %%pstate, %0\n\t"
73 			"andn %0, %1, %0\n\t"
74 			"wrpr %0, %%g0, %%pstate"
75 			: "=&r" (pstate)
76 			: "i" (PSTATE_IE));
77 
78 		if (!need_resched() && !cpu_is_offline(smp_processor_id())) {
79 			sun4v_cpu_yield();
80 			/* If resumed by cpu_poke then we need to explicitly
81 			 * call scheduler_ipi().
82 			 */
83 			scheduler_poke();
84 		}
85 
86 		/* Re-enable interrupts. */
87 		__asm__ __volatile__(
88 			"rdpr %%pstate, %0\n\t"
89 			"or %0, %1, %0\n\t"
90 			"wrpr %0, %%g0, %%pstate"
91 			: "=&r" (pstate)
92 			: "i" (PSTATE_IE));
93 	}
94 }
95 
96 #ifdef CONFIG_HOTPLUG_CPU
97 void arch_cpu_idle_dead(void)
98 {
99 	sched_preempt_enable_no_resched();
100 	cpu_play_dead();
101 }
102 #endif
103 
104 #ifdef CONFIG_COMPAT
105 static void show_regwindow32(struct pt_regs *regs)
106 {
107 	struct reg_window32 __user *rw;
108 	struct reg_window32 r_w;
109 	mm_segment_t old_fs;
110 
111 	__asm__ __volatile__ ("flushw");
112 	rw = compat_ptr((unsigned int)regs->u_regs[14]);
113 	old_fs = get_fs();
114 	set_fs (USER_DS);
115 	if (copy_from_user (&r_w, rw, sizeof(r_w))) {
116 		set_fs (old_fs);
117 		return;
118 	}
119 
120 	set_fs (old_fs);
121 	printk("l0: %08x l1: %08x l2: %08x l3: %08x "
122 	       "l4: %08x l5: %08x l6: %08x l7: %08x\n",
123 	       r_w.locals[0], r_w.locals[1], r_w.locals[2], r_w.locals[3],
124 	       r_w.locals[4], r_w.locals[5], r_w.locals[6], r_w.locals[7]);
125 	printk("i0: %08x i1: %08x i2: %08x i3: %08x "
126 	       "i4: %08x i5: %08x i6: %08x i7: %08x\n",
127 	       r_w.ins[0], r_w.ins[1], r_w.ins[2], r_w.ins[3],
128 	       r_w.ins[4], r_w.ins[5], r_w.ins[6], r_w.ins[7]);
129 }
130 #else
131 #define show_regwindow32(regs)	do { } while (0)
132 #endif
133 
134 static void show_regwindow(struct pt_regs *regs)
135 {
136 	struct reg_window __user *rw;
137 	struct reg_window *rwk;
138 	struct reg_window r_w;
139 	mm_segment_t old_fs;
140 
141 	if ((regs->tstate & TSTATE_PRIV) || !(test_thread_flag(TIF_32BIT))) {
142 		__asm__ __volatile__ ("flushw");
143 		rw = (struct reg_window __user *)
144 			(regs->u_regs[14] + STACK_BIAS);
145 		rwk = (struct reg_window *)
146 			(regs->u_regs[14] + STACK_BIAS);
147 		if (!(regs->tstate & TSTATE_PRIV)) {
148 			old_fs = get_fs();
149 			set_fs (USER_DS);
150 			if (copy_from_user (&r_w, rw, sizeof(r_w))) {
151 				set_fs (old_fs);
152 				return;
153 			}
154 			rwk = &r_w;
155 			set_fs (old_fs);
156 		}
157 	} else {
158 		show_regwindow32(regs);
159 		return;
160 	}
161 	printk("l0: %016lx l1: %016lx l2: %016lx l3: %016lx\n",
162 	       rwk->locals[0], rwk->locals[1], rwk->locals[2], rwk->locals[3]);
163 	printk("l4: %016lx l5: %016lx l6: %016lx l7: %016lx\n",
164 	       rwk->locals[4], rwk->locals[5], rwk->locals[6], rwk->locals[7]);
165 	printk("i0: %016lx i1: %016lx i2: %016lx i3: %016lx\n",
166 	       rwk->ins[0], rwk->ins[1], rwk->ins[2], rwk->ins[3]);
167 	printk("i4: %016lx i5: %016lx i6: %016lx i7: %016lx\n",
168 	       rwk->ins[4], rwk->ins[5], rwk->ins[6], rwk->ins[7]);
169 	if (regs->tstate & TSTATE_PRIV)
170 		printk("I7: <%pS>\n", (void *) rwk->ins[7]);
171 }
172 
173 void show_regs(struct pt_regs *regs)
174 {
175 	show_regs_print_info(KERN_DEFAULT);
176 
177 	printk("TSTATE: %016lx TPC: %016lx TNPC: %016lx Y: %08x    %s\n", regs->tstate,
178 	       regs->tpc, regs->tnpc, regs->y, print_tainted());
179 	printk("TPC: <%pS>\n", (void *) regs->tpc);
180 	printk("g0: %016lx g1: %016lx g2: %016lx g3: %016lx\n",
181 	       regs->u_regs[0], regs->u_regs[1], regs->u_regs[2],
182 	       regs->u_regs[3]);
183 	printk("g4: %016lx g5: %016lx g6: %016lx g7: %016lx\n",
184 	       regs->u_regs[4], regs->u_regs[5], regs->u_regs[6],
185 	       regs->u_regs[7]);
186 	printk("o0: %016lx o1: %016lx o2: %016lx o3: %016lx\n",
187 	       regs->u_regs[8], regs->u_regs[9], regs->u_regs[10],
188 	       regs->u_regs[11]);
189 	printk("o4: %016lx o5: %016lx sp: %016lx ret_pc: %016lx\n",
190 	       regs->u_regs[12], regs->u_regs[13], regs->u_regs[14],
191 	       regs->u_regs[15]);
192 	printk("RPC: <%pS>\n", (void *) regs->u_regs[15]);
193 	show_regwindow(regs);
194 	show_stack(current, (unsigned long *)regs->u_regs[UREG_FP], KERN_DEFAULT);
195 }
196 
197 union global_cpu_snapshot global_cpu_snapshot[NR_CPUS];
198 static DEFINE_SPINLOCK(global_cpu_snapshot_lock);
199 
200 static void __global_reg_self(struct thread_info *tp, struct pt_regs *regs,
201 			      int this_cpu)
202 {
203 	struct global_reg_snapshot *rp;
204 
205 	flushw_all();
206 
207 	rp = &global_cpu_snapshot[this_cpu].reg;
208 
209 	rp->tstate = regs->tstate;
210 	rp->tpc = regs->tpc;
211 	rp->tnpc = regs->tnpc;
212 	rp->o7 = regs->u_regs[UREG_I7];
213 
214 	if (regs->tstate & TSTATE_PRIV) {
215 		struct reg_window *rw;
216 
217 		rw = (struct reg_window *)
218 			(regs->u_regs[UREG_FP] + STACK_BIAS);
219 		if (kstack_valid(tp, (unsigned long) rw)) {
220 			rp->i7 = rw->ins[7];
221 			rw = (struct reg_window *)
222 				(rw->ins[6] + STACK_BIAS);
223 			if (kstack_valid(tp, (unsigned long) rw))
224 				rp->rpc = rw->ins[7];
225 		}
226 	} else {
227 		rp->i7 = 0;
228 		rp->rpc = 0;
229 	}
230 	rp->thread = tp;
231 }
232 
233 /* In order to avoid hangs we do not try to synchronize with the
234  * global register dump client cpus.  The last store they make is to
235  * the thread pointer, so do a short poll waiting for that to become
236  * non-NULL.
237  */
238 static void __global_reg_poll(struct global_reg_snapshot *gp)
239 {
240 	int limit = 0;
241 
242 	while (!gp->thread && ++limit < 100) {
243 		barrier();
244 		udelay(1);
245 	}
246 }
247 
248 void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
249 {
250 	struct thread_info *tp = current_thread_info();
251 	struct pt_regs *regs = get_irq_regs();
252 	unsigned long flags;
253 	int this_cpu, cpu;
254 
255 	if (!regs)
256 		regs = tp->kregs;
257 
258 	spin_lock_irqsave(&global_cpu_snapshot_lock, flags);
259 
260 	this_cpu = raw_smp_processor_id();
261 
262 	memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
263 
264 	if (cpumask_test_cpu(this_cpu, mask) && !exclude_self)
265 		__global_reg_self(tp, regs, this_cpu);
266 
267 	smp_fetch_global_regs();
268 
269 	for_each_cpu(cpu, mask) {
270 		struct global_reg_snapshot *gp;
271 
272 		if (exclude_self && cpu == this_cpu)
273 			continue;
274 
275 		gp = &global_cpu_snapshot[cpu].reg;
276 
277 		__global_reg_poll(gp);
278 
279 		tp = gp->thread;
280 		printk("%c CPU[%3d]: TSTATE[%016lx] TPC[%016lx] TNPC[%016lx] TASK[%s:%d]\n",
281 		       (cpu == this_cpu ? '*' : ' '), cpu,
282 		       gp->tstate, gp->tpc, gp->tnpc,
283 		       ((tp && tp->task) ? tp->task->comm : "NULL"),
284 		       ((tp && tp->task) ? tp->task->pid : -1));
285 
286 		if (gp->tstate & TSTATE_PRIV) {
287 			printk("             TPC[%pS] O7[%pS] I7[%pS] RPC[%pS]\n",
288 			       (void *) gp->tpc,
289 			       (void *) gp->o7,
290 			       (void *) gp->i7,
291 			       (void *) gp->rpc);
292 		} else {
293 			printk("             TPC[%lx] O7[%lx] I7[%lx] RPC[%lx]\n",
294 			       gp->tpc, gp->o7, gp->i7, gp->rpc);
295 		}
296 
297 		touch_nmi_watchdog();
298 	}
299 
300 	memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
301 
302 	spin_unlock_irqrestore(&global_cpu_snapshot_lock, flags);
303 }
304 
305 #ifdef CONFIG_MAGIC_SYSRQ
306 
307 static void sysrq_handle_globreg(int key)
308 {
309 	trigger_all_cpu_backtrace();
310 }
311 
312 static const struct sysrq_key_op sparc_globalreg_op = {
313 	.handler	= sysrq_handle_globreg,
314 	.help_msg	= "global-regs(y)",
315 	.action_msg	= "Show Global CPU Regs",
316 };
317 
318 static void __global_pmu_self(int this_cpu)
319 {
320 	struct global_pmu_snapshot *pp;
321 	int i, num;
322 
323 	if (!pcr_ops)
324 		return;
325 
326 	pp = &global_cpu_snapshot[this_cpu].pmu;
327 
328 	num = 1;
329 	if (tlb_type == hypervisor &&
330 	    sun4v_chip_type >= SUN4V_CHIP_NIAGARA4)
331 		num = 4;
332 
333 	for (i = 0; i < num; i++) {
334 		pp->pcr[i] = pcr_ops->read_pcr(i);
335 		pp->pic[i] = pcr_ops->read_pic(i);
336 	}
337 }
338 
339 static void __global_pmu_poll(struct global_pmu_snapshot *pp)
340 {
341 	int limit = 0;
342 
343 	while (!pp->pcr[0] && ++limit < 100) {
344 		barrier();
345 		udelay(1);
346 	}
347 }
348 
349 static void pmu_snapshot_all_cpus(void)
350 {
351 	unsigned long flags;
352 	int this_cpu, cpu;
353 
354 	spin_lock_irqsave(&global_cpu_snapshot_lock, flags);
355 
356 	memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
357 
358 	this_cpu = raw_smp_processor_id();
359 
360 	__global_pmu_self(this_cpu);
361 
362 	smp_fetch_global_pmu();
363 
364 	for_each_online_cpu(cpu) {
365 		struct global_pmu_snapshot *pp = &global_cpu_snapshot[cpu].pmu;
366 
367 		__global_pmu_poll(pp);
368 
369 		printk("%c CPU[%3d]: PCR[%08lx:%08lx:%08lx:%08lx] PIC[%08lx:%08lx:%08lx:%08lx]\n",
370 		       (cpu == this_cpu ? '*' : ' '), cpu,
371 		       pp->pcr[0], pp->pcr[1], pp->pcr[2], pp->pcr[3],
372 		       pp->pic[0], pp->pic[1], pp->pic[2], pp->pic[3]);
373 
374 		touch_nmi_watchdog();
375 	}
376 
377 	memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
378 
379 	spin_unlock_irqrestore(&global_cpu_snapshot_lock, flags);
380 }
381 
382 static void sysrq_handle_globpmu(int key)
383 {
384 	pmu_snapshot_all_cpus();
385 }
386 
387 static const struct sysrq_key_op sparc_globalpmu_op = {
388 	.handler	= sysrq_handle_globpmu,
389 	.help_msg	= "global-pmu(x)",
390 	.action_msg	= "Show Global PMU Regs",
391 };
392 
393 static int __init sparc_sysrq_init(void)
394 {
395 	int ret = register_sysrq_key('y', &sparc_globalreg_op);
396 
397 	if (!ret)
398 		ret = register_sysrq_key('x', &sparc_globalpmu_op);
399 	return ret;
400 }
401 
402 core_initcall(sparc_sysrq_init);
403 
404 #endif
405 
406 /* Free current thread data structures etc.. */
407 void exit_thread(struct task_struct *tsk)
408 {
409 	struct thread_info *t = task_thread_info(tsk);
410 
411 	if (t->utraps) {
412 		if (t->utraps[0] < 2)
413 			kfree (t->utraps);
414 		else
415 			t->utraps[0]--;
416 	}
417 }
418 
419 void flush_thread(void)
420 {
421 	struct thread_info *t = current_thread_info();
422 	struct mm_struct *mm;
423 
424 	mm = t->task->mm;
425 	if (mm)
426 		tsb_context_switch(mm);
427 
428 	set_thread_wsaved(0);
429 
430 	/* Clear FPU register state. */
431 	t->fpsaved[0] = 0;
432 }
433 
434 /* It's a bit more tricky when 64-bit tasks are involved... */
435 static unsigned long clone_stackframe(unsigned long csp, unsigned long psp)
436 {
437 	bool stack_64bit = test_thread_64bit_stack(psp);
438 	unsigned long fp, distance, rval;
439 
440 	if (stack_64bit) {
441 		csp += STACK_BIAS;
442 		psp += STACK_BIAS;
443 		__get_user(fp, &(((struct reg_window __user *)psp)->ins[6]));
444 		fp += STACK_BIAS;
445 		if (test_thread_flag(TIF_32BIT))
446 			fp &= 0xffffffff;
447 	} else
448 		__get_user(fp, &(((struct reg_window32 __user *)psp)->ins[6]));
449 
450 	/* Now align the stack as this is mandatory in the Sparc ABI
451 	 * due to how register windows work.  This hides the
452 	 * restriction from thread libraries etc.
453 	 */
454 	csp &= ~15UL;
455 
456 	distance = fp - psp;
457 	rval = (csp - distance);
458 	if (raw_copy_in_user((void __user *)rval, (void __user *)psp, distance))
459 		rval = 0;
460 	else if (!stack_64bit) {
461 		if (put_user(((u32)csp),
462 			     &(((struct reg_window32 __user *)rval)->ins[6])))
463 			rval = 0;
464 	} else {
465 		if (put_user(((u64)csp - STACK_BIAS),
466 			     &(((struct reg_window __user *)rval)->ins[6])))
467 			rval = 0;
468 		else
469 			rval = rval - STACK_BIAS;
470 	}
471 
472 	return rval;
473 }
474 
475 /* Standard stuff. */
476 static inline void shift_window_buffer(int first_win, int last_win,
477 				       struct thread_info *t)
478 {
479 	int i;
480 
481 	for (i = first_win; i < last_win; i++) {
482 		t->rwbuf_stkptrs[i] = t->rwbuf_stkptrs[i+1];
483 		memcpy(&t->reg_window[i], &t->reg_window[i+1],
484 		       sizeof(struct reg_window));
485 	}
486 }
487 
488 void synchronize_user_stack(void)
489 {
490 	struct thread_info *t = current_thread_info();
491 	unsigned long window;
492 
493 	flush_user_windows();
494 	if ((window = get_thread_wsaved()) != 0) {
495 		window -= 1;
496 		do {
497 			struct reg_window *rwin = &t->reg_window[window];
498 			int winsize = sizeof(struct reg_window);
499 			unsigned long sp;
500 
501 			sp = t->rwbuf_stkptrs[window];
502 
503 			if (test_thread_64bit_stack(sp))
504 				sp += STACK_BIAS;
505 			else
506 				winsize = sizeof(struct reg_window32);
507 
508 			if (!copy_to_user((char __user *)sp, rwin, winsize)) {
509 				shift_window_buffer(window, get_thread_wsaved() - 1, t);
510 				set_thread_wsaved(get_thread_wsaved() - 1);
511 			}
512 		} while (window--);
513 	}
514 }
515 
516 static void stack_unaligned(unsigned long sp)
517 {
518 	force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *) sp);
519 }
520 
521 static const char uwfault32[] = KERN_INFO \
522 	"%s[%d]: bad register window fault: SP %08lx (orig_sp %08lx) TPC %08lx O7 %08lx\n";
523 static const char uwfault64[] = KERN_INFO \
524 	"%s[%d]: bad register window fault: SP %016lx (orig_sp %016lx) TPC %08lx O7 %016lx\n";
525 
526 void fault_in_user_windows(struct pt_regs *regs)
527 {
528 	struct thread_info *t = current_thread_info();
529 	unsigned long window;
530 
531 	flush_user_windows();
532 	window = get_thread_wsaved();
533 
534 	if (likely(window != 0)) {
535 		window -= 1;
536 		do {
537 			struct reg_window *rwin = &t->reg_window[window];
538 			int winsize = sizeof(struct reg_window);
539 			unsigned long sp, orig_sp;
540 
541 			orig_sp = sp = t->rwbuf_stkptrs[window];
542 
543 			if (test_thread_64bit_stack(sp))
544 				sp += STACK_BIAS;
545 			else
546 				winsize = sizeof(struct reg_window32);
547 
548 			if (unlikely(sp & 0x7UL))
549 				stack_unaligned(sp);
550 
551 			if (unlikely(copy_to_user((char __user *)sp,
552 						  rwin, winsize))) {
553 				if (show_unhandled_signals)
554 					printk_ratelimited(is_compat_task() ?
555 							   uwfault32 : uwfault64,
556 							   current->comm, current->pid,
557 							   sp, orig_sp,
558 							   regs->tpc,
559 							   regs->u_regs[UREG_I7]);
560 				goto barf;
561 			}
562 		} while (window--);
563 	}
564 	set_thread_wsaved(0);
565 	return;
566 
567 barf:
568 	set_thread_wsaved(window + 1);
569 	force_sig(SIGSEGV);
570 }
571 
572 /* Copy a Sparc thread.  The fork() return value conventions
573  * under SunOS are nothing short of bletcherous:
574  * Parent -->  %o0 == childs  pid, %o1 == 0
575  * Child  -->  %o0 == parents pid, %o1 == 1
576  */
577 int copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long arg,
578 		struct task_struct *p, unsigned long tls)
579 {
580 	struct thread_info *t = task_thread_info(p);
581 	struct pt_regs *regs = current_pt_regs();
582 	struct sparc_stackf *parent_sf;
583 	unsigned long child_stack_sz;
584 	char *child_trap_frame;
585 
586 	/* Calculate offset to stack_frame & pt_regs */
587 	child_stack_sz = (STACKFRAME_SZ + TRACEREG_SZ);
588 	child_trap_frame = (task_stack_page(p) +
589 			    (THREAD_SIZE - child_stack_sz));
590 
591 	t->new_child = 1;
592 	t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS;
593 	t->kregs = (struct pt_regs *) (child_trap_frame +
594 				       sizeof(struct sparc_stackf));
595 	t->fpsaved[0] = 0;
596 
597 	if (unlikely(p->flags & (PF_KTHREAD | PF_IO_WORKER))) {
598 		memset(child_trap_frame, 0, child_stack_sz);
599 		__thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] =
600 			(current_pt_regs()->tstate + 1) & TSTATE_CWP;
601 		t->current_ds = ASI_P;
602 		t->kregs->u_regs[UREG_G1] = sp; /* function */
603 		t->kregs->u_regs[UREG_G2] = arg;
604 		return 0;
605 	}
606 
607 	parent_sf = ((struct sparc_stackf *) regs) - 1;
608 	memcpy(child_trap_frame, parent_sf, child_stack_sz);
609 	if (t->flags & _TIF_32BIT) {
610 		sp &= 0x00000000ffffffffUL;
611 		regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
612 	}
613 	t->kregs->u_regs[UREG_FP] = sp;
614 	__thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] =
615 		(regs->tstate + 1) & TSTATE_CWP;
616 	t->current_ds = ASI_AIUS;
617 	if (sp != regs->u_regs[UREG_FP]) {
618 		unsigned long csp;
619 
620 		csp = clone_stackframe(sp, regs->u_regs[UREG_FP]);
621 		if (!csp)
622 			return -EFAULT;
623 		t->kregs->u_regs[UREG_FP] = csp;
624 	}
625 	if (t->utraps)
626 		t->utraps[0]++;
627 
628 	/* Set the return value for the child. */
629 	t->kregs->u_regs[UREG_I0] = current->pid;
630 	t->kregs->u_regs[UREG_I1] = 1;
631 
632 	/* Set the second return value for the parent. */
633 	regs->u_regs[UREG_I1] = 0;
634 
635 	if (clone_flags & CLONE_SETTLS)
636 		t->kregs->u_regs[UREG_G7] = tls;
637 
638 	return 0;
639 }
640 
641 /* TIF_MCDPER in thread info flags for current task is updated lazily upon
642  * a context switch. Update this flag in current task's thread flags
643  * before dup so the dup'd task will inherit the current TIF_MCDPER flag.
644  */
645 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
646 {
647 	if (adi_capable()) {
648 		register unsigned long tmp_mcdper;
649 
650 		__asm__ __volatile__(
651 			".word 0x83438000\n\t"	/* rd  %mcdper, %g1 */
652 			"mov %%g1, %0\n\t"
653 			: "=r" (tmp_mcdper)
654 			:
655 			: "g1");
656 		if (tmp_mcdper)
657 			set_thread_flag(TIF_MCDPER);
658 		else
659 			clear_thread_flag(TIF_MCDPER);
660 	}
661 
662 	*dst = *src;
663 	return 0;
664 }
665 
666 unsigned long __get_wchan(struct task_struct *task)
667 {
668 	unsigned long pc, fp, bias = 0;
669 	struct thread_info *tp;
670 	struct reg_window *rw;
671         unsigned long ret = 0;
672 	int count = 0;
673 
674 	tp = task_thread_info(task);
675 	bias = STACK_BIAS;
676 	fp = task_thread_info(task)->ksp + bias;
677 
678 	do {
679 		if (!kstack_valid(tp, fp))
680 			break;
681 		rw = (struct reg_window *) fp;
682 		pc = rw->ins[7];
683 		if (!in_sched_functions(pc)) {
684 			ret = pc;
685 			goto out;
686 		}
687 		fp = rw->ins[6] + bias;
688 	} while (++count < 16);
689 
690 out:
691 	return ret;
692 }
693