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. */
58void arch_cpu_idle(void)
59{
60	if (tlb_type != hypervisor) {
61		touch_nmi_watchdog();
62	} else {
63		unsigned long pstate;
64
65		raw_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			/* If resumed by cpu_poke then we need to explicitly
80			 * call scheduler_ipi().
81			 */
82			scheduler_poke();
83		}
84
85		/* Re-enable interrupts. */
86		__asm__ __volatile__(
87			"rdpr %%pstate, %0\n\t"
88			"or %0, %1, %0\n\t"
89			"wrpr %0, %%g0, %%pstate"
90			: "=&r" (pstate)
91			: "i" (PSTATE_IE));
92
93		raw_local_irq_disable();
94	}
95}
96
97#ifdef CONFIG_HOTPLUG_CPU
98void __noreturn arch_cpu_idle_dead(void)
99{
100	sched_preempt_enable_no_resched();
101	cpu_play_dead();
102}
103#endif
104
105#ifdef CONFIG_COMPAT
106static void show_regwindow32(struct pt_regs *regs)
107{
108	struct reg_window32 __user *rw;
109	struct reg_window32 r_w;
110
111	__asm__ __volatile__ ("flushw");
112	rw = compat_ptr((unsigned int)regs->u_regs[14]);
113	if (copy_from_user (&r_w, rw, sizeof(r_w))) {
114		return;
115	}
116
117	printk("l0: %08x l1: %08x l2: %08x l3: %08x "
118	       "l4: %08x l5: %08x l6: %08x l7: %08x\n",
119	       r_w.locals[0], r_w.locals[1], r_w.locals[2], r_w.locals[3],
120	       r_w.locals[4], r_w.locals[5], r_w.locals[6], r_w.locals[7]);
121	printk("i0: %08x i1: %08x i2: %08x i3: %08x "
122	       "i4: %08x i5: %08x i6: %08x i7: %08x\n",
123	       r_w.ins[0], r_w.ins[1], r_w.ins[2], r_w.ins[3],
124	       r_w.ins[4], r_w.ins[5], r_w.ins[6], r_w.ins[7]);
125}
126#else
127#define show_regwindow32(regs)	do { } while (0)
128#endif
129
130static void show_regwindow(struct pt_regs *regs)
131{
132	struct reg_window __user *rw;
133	struct reg_window *rwk;
134	struct reg_window r_w;
135
136	if ((regs->tstate & TSTATE_PRIV) || !(test_thread_flag(TIF_32BIT))) {
137		__asm__ __volatile__ ("flushw");
138		rw = (struct reg_window __user *)
139			(regs->u_regs[14] + STACK_BIAS);
140		rwk = (struct reg_window *)
141			(regs->u_regs[14] + STACK_BIAS);
142		if (!(regs->tstate & TSTATE_PRIV)) {
143			if (copy_from_user (&r_w, rw, sizeof(r_w))) {
144				return;
145			}
146			rwk = &r_w;
147		}
148	} else {
149		show_regwindow32(regs);
150		return;
151	}
152	printk("l0: %016lx l1: %016lx l2: %016lx l3: %016lx\n",
153	       rwk->locals[0], rwk->locals[1], rwk->locals[2], rwk->locals[3]);
154	printk("l4: %016lx l5: %016lx l6: %016lx l7: %016lx\n",
155	       rwk->locals[4], rwk->locals[5], rwk->locals[6], rwk->locals[7]);
156	printk("i0: %016lx i1: %016lx i2: %016lx i3: %016lx\n",
157	       rwk->ins[0], rwk->ins[1], rwk->ins[2], rwk->ins[3]);
158	printk("i4: %016lx i5: %016lx i6: %016lx i7: %016lx\n",
159	       rwk->ins[4], rwk->ins[5], rwk->ins[6], rwk->ins[7]);
160	if (regs->tstate & TSTATE_PRIV)
161		printk("I7: <%pS>\n", (void *) rwk->ins[7]);
162}
163
164void show_regs(struct pt_regs *regs)
165{
166	show_regs_print_info(KERN_DEFAULT);
167
168	printk("TSTATE: %016lx TPC: %016lx TNPC: %016lx Y: %08x    %s\n", regs->tstate,
169	       regs->tpc, regs->tnpc, regs->y, print_tainted());
170	printk("TPC: <%pS>\n", (void *) regs->tpc);
171	printk("g0: %016lx g1: %016lx g2: %016lx g3: %016lx\n",
172	       regs->u_regs[0], regs->u_regs[1], regs->u_regs[2],
173	       regs->u_regs[3]);
174	printk("g4: %016lx g5: %016lx g6: %016lx g7: %016lx\n",
175	       regs->u_regs[4], regs->u_regs[5], regs->u_regs[6],
176	       regs->u_regs[7]);
177	printk("o0: %016lx o1: %016lx o2: %016lx o3: %016lx\n",
178	       regs->u_regs[8], regs->u_regs[9], regs->u_regs[10],
179	       regs->u_regs[11]);
180	printk("o4: %016lx o5: %016lx sp: %016lx ret_pc: %016lx\n",
181	       regs->u_regs[12], regs->u_regs[13], regs->u_regs[14],
182	       regs->u_regs[15]);
183	printk("RPC: <%pS>\n", (void *) regs->u_regs[15]);
184	show_regwindow(regs);
185	show_stack(current, (unsigned long *)regs->u_regs[UREG_FP], KERN_DEFAULT);
186}
187
188union global_cpu_snapshot global_cpu_snapshot[NR_CPUS];
189static DEFINE_SPINLOCK(global_cpu_snapshot_lock);
190
191static void __global_reg_self(struct thread_info *tp, struct pt_regs *regs,
192			      int this_cpu)
193{
194	struct global_reg_snapshot *rp;
195
196	flushw_all();
197
198	rp = &global_cpu_snapshot[this_cpu].reg;
199
200	rp->tstate = regs->tstate;
201	rp->tpc = regs->tpc;
202	rp->tnpc = regs->tnpc;
203	rp->o7 = regs->u_regs[UREG_I7];
204
205	if (regs->tstate & TSTATE_PRIV) {
206		struct reg_window *rw;
207
208		rw = (struct reg_window *)
209			(regs->u_regs[UREG_FP] + STACK_BIAS);
210		if (kstack_valid(tp, (unsigned long) rw)) {
211			rp->i7 = rw->ins[7];
212			rw = (struct reg_window *)
213				(rw->ins[6] + STACK_BIAS);
214			if (kstack_valid(tp, (unsigned long) rw))
215				rp->rpc = rw->ins[7];
216		}
217	} else {
218		rp->i7 = 0;
219		rp->rpc = 0;
220	}
221	rp->thread = tp;
222}
223
224/* In order to avoid hangs we do not try to synchronize with the
225 * global register dump client cpus.  The last store they make is to
226 * the thread pointer, so do a short poll waiting for that to become
227 * non-NULL.
228 */
229static void __global_reg_poll(struct global_reg_snapshot *gp)
230{
231	int limit = 0;
232
233	while (!gp->thread && ++limit < 100) {
234		barrier();
235		udelay(1);
236	}
237}
238
239void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu)
240{
241	struct thread_info *tp = current_thread_info();
242	struct pt_regs *regs = get_irq_regs();
243	unsigned long flags;
244	int this_cpu, cpu;
245
246	if (!regs)
247		regs = tp->kregs;
248
249	spin_lock_irqsave(&global_cpu_snapshot_lock, flags);
250
251	this_cpu = raw_smp_processor_id();
252
253	memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
254
255	if (cpumask_test_cpu(this_cpu, mask) && this_cpu != exclude_cpu)
256		__global_reg_self(tp, regs, this_cpu);
257
258	smp_fetch_global_regs();
259
260	for_each_cpu(cpu, mask) {
261		struct global_reg_snapshot *gp;
262
263		if (cpu == exclude_cpu)
264			continue;
265
266		gp = &global_cpu_snapshot[cpu].reg;
267
268		__global_reg_poll(gp);
269
270		tp = gp->thread;
271		printk("%c CPU[%3d]: TSTATE[%016lx] TPC[%016lx] TNPC[%016lx] TASK[%s:%d]\n",
272		       (cpu == this_cpu ? '*' : ' '), cpu,
273		       gp->tstate, gp->tpc, gp->tnpc,
274		       ((tp && tp->task) ? tp->task->comm : "NULL"),
275		       ((tp && tp->task) ? tp->task->pid : -1));
276
277		if (gp->tstate & TSTATE_PRIV) {
278			printk("             TPC[%pS] O7[%pS] I7[%pS] RPC[%pS]\n",
279			       (void *) gp->tpc,
280			       (void *) gp->o7,
281			       (void *) gp->i7,
282			       (void *) gp->rpc);
283		} else {
284			printk("             TPC[%lx] O7[%lx] I7[%lx] RPC[%lx]\n",
285			       gp->tpc, gp->o7, gp->i7, gp->rpc);
286		}
287
288		touch_nmi_watchdog();
289	}
290
291	memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
292
293	spin_unlock_irqrestore(&global_cpu_snapshot_lock, flags);
294}
295
296#ifdef CONFIG_MAGIC_SYSRQ
297
298static void sysrq_handle_globreg(u8 key)
299{
300	trigger_all_cpu_backtrace();
301}
302
303static const struct sysrq_key_op sparc_globalreg_op = {
304	.handler	= sysrq_handle_globreg,
305	.help_msg	= "global-regs(y)",
306	.action_msg	= "Show Global CPU Regs",
307};
308
309static void __global_pmu_self(int this_cpu)
310{
311	struct global_pmu_snapshot *pp;
312	int i, num;
313
314	if (!pcr_ops)
315		return;
316
317	pp = &global_cpu_snapshot[this_cpu].pmu;
318
319	num = 1;
320	if (tlb_type == hypervisor &&
321	    sun4v_chip_type >= SUN4V_CHIP_NIAGARA4)
322		num = 4;
323
324	for (i = 0; i < num; i++) {
325		pp->pcr[i] = pcr_ops->read_pcr(i);
326		pp->pic[i] = pcr_ops->read_pic(i);
327	}
328}
329
330static void __global_pmu_poll(struct global_pmu_snapshot *pp)
331{
332	int limit = 0;
333
334	while (!pp->pcr[0] && ++limit < 100) {
335		barrier();
336		udelay(1);
337	}
338}
339
340static void pmu_snapshot_all_cpus(void)
341{
342	unsigned long flags;
343	int this_cpu, cpu;
344
345	spin_lock_irqsave(&global_cpu_snapshot_lock, flags);
346
347	memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
348
349	this_cpu = raw_smp_processor_id();
350
351	__global_pmu_self(this_cpu);
352
353	smp_fetch_global_pmu();
354
355	for_each_online_cpu(cpu) {
356		struct global_pmu_snapshot *pp = &global_cpu_snapshot[cpu].pmu;
357
358		__global_pmu_poll(pp);
359
360		printk("%c CPU[%3d]: PCR[%08lx:%08lx:%08lx:%08lx] PIC[%08lx:%08lx:%08lx:%08lx]\n",
361		       (cpu == this_cpu ? '*' : ' '), cpu,
362		       pp->pcr[0], pp->pcr[1], pp->pcr[2], pp->pcr[3],
363		       pp->pic[0], pp->pic[1], pp->pic[2], pp->pic[3]);
364
365		touch_nmi_watchdog();
366	}
367
368	memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
369
370	spin_unlock_irqrestore(&global_cpu_snapshot_lock, flags);
371}
372
373static void sysrq_handle_globpmu(u8 key)
374{
375	pmu_snapshot_all_cpus();
376}
377
378static const struct sysrq_key_op sparc_globalpmu_op = {
379	.handler	= sysrq_handle_globpmu,
380	.help_msg	= "global-pmu(x)",
381	.action_msg	= "Show Global PMU Regs",
382};
383
384static int __init sparc_sysrq_init(void)
385{
386	int ret = register_sysrq_key('y', &sparc_globalreg_op);
387
388	if (!ret)
389		ret = register_sysrq_key('x', &sparc_globalpmu_op);
390	return ret;
391}
392
393core_initcall(sparc_sysrq_init);
394
395#endif
396
397/* Free current thread data structures etc.. */
398void exit_thread(struct task_struct *tsk)
399{
400	struct thread_info *t = task_thread_info(tsk);
401
402	if (t->utraps) {
403		if (t->utraps[0] < 2)
404			kfree (t->utraps);
405		else
406			t->utraps[0]--;
407	}
408}
409
410void flush_thread(void)
411{
412	struct thread_info *t = current_thread_info();
413	struct mm_struct *mm;
414
415	mm = t->task->mm;
416	if (mm)
417		tsb_context_switch(mm);
418
419	set_thread_wsaved(0);
420
421	/* Clear FPU register state. */
422	t->fpsaved[0] = 0;
423}
424
425/* It's a bit more tricky when 64-bit tasks are involved... */
426static unsigned long clone_stackframe(unsigned long csp, unsigned long psp)
427{
428	bool stack_64bit = test_thread_64bit_stack(psp);
429	unsigned long fp, distance, rval;
430
431	if (stack_64bit) {
432		csp += STACK_BIAS;
433		psp += STACK_BIAS;
434		__get_user(fp, &(((struct reg_window __user *)psp)->ins[6]));
435		fp += STACK_BIAS;
436		if (test_thread_flag(TIF_32BIT))
437			fp &= 0xffffffff;
438	} else
439		__get_user(fp, &(((struct reg_window32 __user *)psp)->ins[6]));
440
441	/* Now align the stack as this is mandatory in the Sparc ABI
442	 * due to how register windows work.  This hides the
443	 * restriction from thread libraries etc.
444	 */
445	csp &= ~15UL;
446
447	distance = fp - psp;
448	rval = (csp - distance);
449	if (raw_copy_in_user((void __user *)rval, (void __user *)psp, distance))
450		rval = 0;
451	else if (!stack_64bit) {
452		if (put_user(((u32)csp),
453			     &(((struct reg_window32 __user *)rval)->ins[6])))
454			rval = 0;
455	} else {
456		if (put_user(((u64)csp - STACK_BIAS),
457			     &(((struct reg_window __user *)rval)->ins[6])))
458			rval = 0;
459		else
460			rval = rval - STACK_BIAS;
461	}
462
463	return rval;
464}
465
466/* Standard stuff. */
467static inline void shift_window_buffer(int first_win, int last_win,
468				       struct thread_info *t)
469{
470	int i;
471
472	for (i = first_win; i < last_win; i++) {
473		t->rwbuf_stkptrs[i] = t->rwbuf_stkptrs[i+1];
474		memcpy(&t->reg_window[i], &t->reg_window[i+1],
475		       sizeof(struct reg_window));
476	}
477}
478
479void synchronize_user_stack(void)
480{
481	struct thread_info *t = current_thread_info();
482	unsigned long window;
483
484	flush_user_windows();
485	if ((window = get_thread_wsaved()) != 0) {
486		window -= 1;
487		do {
488			struct reg_window *rwin = &t->reg_window[window];
489			int winsize = sizeof(struct reg_window);
490			unsigned long sp;
491
492			sp = t->rwbuf_stkptrs[window];
493
494			if (test_thread_64bit_stack(sp))
495				sp += STACK_BIAS;
496			else
497				winsize = sizeof(struct reg_window32);
498
499			if (!copy_to_user((char __user *)sp, rwin, winsize)) {
500				shift_window_buffer(window, get_thread_wsaved() - 1, t);
501				set_thread_wsaved(get_thread_wsaved() - 1);
502			}
503		} while (window--);
504	}
505}
506
507static void stack_unaligned(unsigned long sp)
508{
509	force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *) sp);
510}
511
512static const char uwfault32[] = KERN_INFO \
513	"%s[%d]: bad register window fault: SP %08lx (orig_sp %08lx) TPC %08lx O7 %08lx\n";
514static const char uwfault64[] = KERN_INFO \
515	"%s[%d]: bad register window fault: SP %016lx (orig_sp %016lx) TPC %08lx O7 %016lx\n";
516
517void fault_in_user_windows(struct pt_regs *regs)
518{
519	struct thread_info *t = current_thread_info();
520	unsigned long window;
521
522	flush_user_windows();
523	window = get_thread_wsaved();
524
525	if (likely(window != 0)) {
526		window -= 1;
527		do {
528			struct reg_window *rwin = &t->reg_window[window];
529			int winsize = sizeof(struct reg_window);
530			unsigned long sp, orig_sp;
531
532			orig_sp = sp = t->rwbuf_stkptrs[window];
533
534			if (test_thread_64bit_stack(sp))
535				sp += STACK_BIAS;
536			else
537				winsize = sizeof(struct reg_window32);
538
539			if (unlikely(sp & 0x7UL))
540				stack_unaligned(sp);
541
542			if (unlikely(copy_to_user((char __user *)sp,
543						  rwin, winsize))) {
544				if (show_unhandled_signals)
545					printk_ratelimited(is_compat_task() ?
546							   uwfault32 : uwfault64,
547							   current->comm, current->pid,
548							   sp, orig_sp,
549							   regs->tpc,
550							   regs->u_regs[UREG_I7]);
551				goto barf;
552			}
553		} while (window--);
554	}
555	set_thread_wsaved(0);
556	return;
557
558barf:
559	set_thread_wsaved(window + 1);
560	force_sig(SIGSEGV);
561}
562
563/* Copy a Sparc thread.  The fork() return value conventions
564 * under SunOS are nothing short of bletcherous:
565 * Parent -->  %o0 == childs  pid, %o1 == 0
566 * Child  -->  %o0 == parents pid, %o1 == 1
567 */
568int copy_thread(struct task_struct *p, const struct kernel_clone_args *args)
569{
570	unsigned long clone_flags = args->flags;
571	unsigned long sp = args->stack;
572	unsigned long tls = args->tls;
573	struct thread_info *t = task_thread_info(p);
574	struct pt_regs *regs = current_pt_regs();
575	struct sparc_stackf *parent_sf;
576	unsigned long child_stack_sz;
577	char *child_trap_frame;
578
579	/* Calculate offset to stack_frame & pt_regs */
580	child_stack_sz = (STACKFRAME_SZ + TRACEREG_SZ);
581	child_trap_frame = (task_stack_page(p) +
582			    (THREAD_SIZE - child_stack_sz));
583
584	t->new_child = 1;
585	t->ksp = ((unsigned long) child_trap_frame) - STACK_BIAS;
586	t->kregs = (struct pt_regs *) (child_trap_frame +
587				       sizeof(struct sparc_stackf));
588	t->fpsaved[0] = 0;
589
590	if (unlikely(args->fn)) {
591		memset(child_trap_frame, 0, child_stack_sz);
592		__thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] =
593			(current_pt_regs()->tstate + 1) & TSTATE_CWP;
594		t->kregs->u_regs[UREG_G1] = (unsigned long) args->fn;
595		t->kregs->u_regs[UREG_G2] = (unsigned long) args->fn_arg;
596		return 0;
597	}
598
599	parent_sf = ((struct sparc_stackf *) regs) - 1;
600	memcpy(child_trap_frame, parent_sf, child_stack_sz);
601	if (t->flags & _TIF_32BIT) {
602		sp &= 0x00000000ffffffffUL;
603		regs->u_regs[UREG_FP] &= 0x00000000ffffffffUL;
604	}
605	t->kregs->u_regs[UREG_FP] = sp;
606	__thread_flag_byte_ptr(t)[TI_FLAG_BYTE_CWP] =
607		(regs->tstate + 1) & TSTATE_CWP;
608	if (sp != regs->u_regs[UREG_FP]) {
609		unsigned long csp;
610
611		csp = clone_stackframe(sp, regs->u_regs[UREG_FP]);
612		if (!csp)
613			return -EFAULT;
614		t->kregs->u_regs[UREG_FP] = csp;
615	}
616	if (t->utraps)
617		t->utraps[0]++;
618
619	/* Set the return value for the child. */
620	t->kregs->u_regs[UREG_I0] = current->pid;
621	t->kregs->u_regs[UREG_I1] = 1;
622
623	/* Set the second return value for the parent. */
624	regs->u_regs[UREG_I1] = 0;
625
626	if (clone_flags & CLONE_SETTLS)
627		t->kregs->u_regs[UREG_G7] = tls;
628
629	return 0;
630}
631
632/* TIF_MCDPER in thread info flags for current task is updated lazily upon
633 * a context switch. Update this flag in current task's thread flags
634 * before dup so the dup'd task will inherit the current TIF_MCDPER flag.
635 */
636int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
637{
638	if (adi_capable()) {
639		register unsigned long tmp_mcdper;
640
641		__asm__ __volatile__(
642			".word 0x83438000\n\t"	/* rd  %mcdper, %g1 */
643			"mov %%g1, %0\n\t"
644			: "=r" (tmp_mcdper)
645			:
646			: "g1");
647		if (tmp_mcdper)
648			set_thread_flag(TIF_MCDPER);
649		else
650			clear_thread_flag(TIF_MCDPER);
651	}
652
653	*dst = *src;
654	return 0;
655}
656
657unsigned long __get_wchan(struct task_struct *task)
658{
659	unsigned long pc, fp, bias = 0;
660	struct thread_info *tp;
661	struct reg_window *rw;
662        unsigned long ret = 0;
663	int count = 0;
664
665	tp = task_thread_info(task);
666	bias = STACK_BIAS;
667	fp = task_thread_info(task)->ksp + bias;
668
669	do {
670		if (!kstack_valid(tp, fp))
671			break;
672		rw = (struct reg_window *) fp;
673		pc = rw->ins[7];
674		if (!in_sched_functions(pc)) {
675			ret = pc;
676			goto out;
677		}
678		fp = rw->ins[6] + bias;
679	} while (++count < 16);
680
681out:
682	return ret;
683}
684