xref: /openbmc/linux/arch/mips/kernel/traps.c (revision 99b7e93c)
1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Copyright (C) 1994 - 1999, 2000, 01, 06 Ralf Baechle
7  * Copyright (C) 1995, 1996 Paul M. Antoine
8  * Copyright (C) 1998 Ulf Carlsson
9  * Copyright (C) 1999 Silicon Graphics, Inc.
10  * Kevin D. Kissell, kevink@mips.com and Carsten Langgaard, carstenl@mips.com
11  * Copyright (C) 2002, 2003, 2004, 2005, 2007  Maciej W. Rozycki
12  * Copyright (C) 2000, 2001, 2012 MIPS Technologies, Inc.  All rights reserved.
13  * Copyright (C) 2014, Imagination Technologies Ltd.
14  */
15 #include <linux/bitops.h>
16 #include <linux/bug.h>
17 #include <linux/compiler.h>
18 #include <linux/context_tracking.h>
19 #include <linux/cpu_pm.h>
20 #include <linux/kexec.h>
21 #include <linux/init.h>
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/mm.h>
25 #include <linux/sched.h>
26 #include <linux/smp.h>
27 #include <linux/spinlock.h>
28 #include <linux/kallsyms.h>
29 #include <linux/bootmem.h>
30 #include <linux/interrupt.h>
31 #include <linux/ptrace.h>
32 #include <linux/kgdb.h>
33 #include <linux/kdebug.h>
34 #include <linux/kprobes.h>
35 #include <linux/notifier.h>
36 #include <linux/kdb.h>
37 #include <linux/irq.h>
38 #include <linux/perf_event.h>
39 
40 #include <asm/bootinfo.h>
41 #include <asm/branch.h>
42 #include <asm/break.h>
43 #include <asm/cop2.h>
44 #include <asm/cpu.h>
45 #include <asm/cpu-type.h>
46 #include <asm/dsp.h>
47 #include <asm/fpu.h>
48 #include <asm/fpu_emulator.h>
49 #include <asm/idle.h>
50 #include <asm/mips-r2-to-r6-emul.h>
51 #include <asm/mipsregs.h>
52 #include <asm/mipsmtregs.h>
53 #include <asm/module.h>
54 #include <asm/msa.h>
55 #include <asm/pgtable.h>
56 #include <asm/ptrace.h>
57 #include <asm/sections.h>
58 #include <asm/tlbdebug.h>
59 #include <asm/traps.h>
60 #include <asm/uaccess.h>
61 #include <asm/watch.h>
62 #include <asm/mmu_context.h>
63 #include <asm/types.h>
64 #include <asm/stacktrace.h>
65 #include <asm/uasm.h>
66 
67 extern void check_wait(void);
68 extern asmlinkage void rollback_handle_int(void);
69 extern asmlinkage void handle_int(void);
70 extern u32 handle_tlbl[];
71 extern u32 handle_tlbs[];
72 extern u32 handle_tlbm[];
73 extern asmlinkage void handle_adel(void);
74 extern asmlinkage void handle_ades(void);
75 extern asmlinkage void handle_ibe(void);
76 extern asmlinkage void handle_dbe(void);
77 extern asmlinkage void handle_sys(void);
78 extern asmlinkage void handle_bp(void);
79 extern asmlinkage void handle_ri(void);
80 extern asmlinkage void handle_ri_rdhwr_vivt(void);
81 extern asmlinkage void handle_ri_rdhwr(void);
82 extern asmlinkage void handle_cpu(void);
83 extern asmlinkage void handle_ov(void);
84 extern asmlinkage void handle_tr(void);
85 extern asmlinkage void handle_msa_fpe(void);
86 extern asmlinkage void handle_fpe(void);
87 extern asmlinkage void handle_ftlb(void);
88 extern asmlinkage void handle_msa(void);
89 extern asmlinkage void handle_mdmx(void);
90 extern asmlinkage void handle_watch(void);
91 extern asmlinkage void handle_mt(void);
92 extern asmlinkage void handle_dsp(void);
93 extern asmlinkage void handle_mcheck(void);
94 extern asmlinkage void handle_reserved(void);
95 extern void tlb_do_page_fault_0(void);
96 
97 void (*board_be_init)(void);
98 int (*board_be_handler)(struct pt_regs *regs, int is_fixup);
99 void (*board_nmi_handler_setup)(void);
100 void (*board_ejtag_handler_setup)(void);
101 void (*board_bind_eic_interrupt)(int irq, int regset);
102 void (*board_ebase_setup)(void);
103 void(*board_cache_error_setup)(void);
104 
105 static void show_raw_backtrace(unsigned long reg29)
106 {
107 	unsigned long *sp = (unsigned long *)(reg29 & ~3);
108 	unsigned long addr;
109 
110 	printk("Call Trace:");
111 #ifdef CONFIG_KALLSYMS
112 	printk("\n");
113 #endif
114 	while (!kstack_end(sp)) {
115 		unsigned long __user *p =
116 			(unsigned long __user *)(unsigned long)sp++;
117 		if (__get_user(addr, p)) {
118 			printk(" (Bad stack address)");
119 			break;
120 		}
121 		if (__kernel_text_address(addr))
122 			print_ip_sym(addr);
123 	}
124 	printk("\n");
125 }
126 
127 #ifdef CONFIG_KALLSYMS
128 int raw_show_trace;
129 static int __init set_raw_show_trace(char *str)
130 {
131 	raw_show_trace = 1;
132 	return 1;
133 }
134 __setup("raw_show_trace", set_raw_show_trace);
135 #endif
136 
137 static void show_backtrace(struct task_struct *task, const struct pt_regs *regs)
138 {
139 	unsigned long sp = regs->regs[29];
140 	unsigned long ra = regs->regs[31];
141 	unsigned long pc = regs->cp0_epc;
142 
143 	if (!task)
144 		task = current;
145 
146 	if (raw_show_trace || !__kernel_text_address(pc)) {
147 		show_raw_backtrace(sp);
148 		return;
149 	}
150 	printk("Call Trace:\n");
151 	do {
152 		print_ip_sym(pc);
153 		pc = unwind_stack(task, &sp, pc, &ra);
154 	} while (pc);
155 	printk("\n");
156 }
157 
158 /*
159  * This routine abuses get_user()/put_user() to reference pointers
160  * with at least a bit of error checking ...
161  */
162 static void show_stacktrace(struct task_struct *task,
163 	const struct pt_regs *regs)
164 {
165 	const int field = 2 * sizeof(unsigned long);
166 	long stackdata;
167 	int i;
168 	unsigned long __user *sp = (unsigned long __user *)regs->regs[29];
169 
170 	printk("Stack :");
171 	i = 0;
172 	while ((unsigned long) sp & (PAGE_SIZE - 1)) {
173 		if (i && ((i % (64 / field)) == 0))
174 			printk("\n	 ");
175 		if (i > 39) {
176 			printk(" ...");
177 			break;
178 		}
179 
180 		if (__get_user(stackdata, sp++)) {
181 			printk(" (Bad stack address)");
182 			break;
183 		}
184 
185 		printk(" %0*lx", field, stackdata);
186 		i++;
187 	}
188 	printk("\n");
189 	show_backtrace(task, regs);
190 }
191 
192 void show_stack(struct task_struct *task, unsigned long *sp)
193 {
194 	struct pt_regs regs;
195 	if (sp) {
196 		regs.regs[29] = (unsigned long)sp;
197 		regs.regs[31] = 0;
198 		regs.cp0_epc = 0;
199 	} else {
200 		if (task && task != current) {
201 			regs.regs[29] = task->thread.reg29;
202 			regs.regs[31] = 0;
203 			regs.cp0_epc = task->thread.reg31;
204 #ifdef CONFIG_KGDB_KDB
205 		} else if (atomic_read(&kgdb_active) != -1 &&
206 			   kdb_current_regs) {
207 			memcpy(&regs, kdb_current_regs, sizeof(regs));
208 #endif /* CONFIG_KGDB_KDB */
209 		} else {
210 			prepare_frametrace(&regs);
211 		}
212 	}
213 	show_stacktrace(task, &regs);
214 }
215 
216 static void show_code(unsigned int __user *pc)
217 {
218 	long i;
219 	unsigned short __user *pc16 = NULL;
220 
221 	printk("\nCode:");
222 
223 	if ((unsigned long)pc & 1)
224 		pc16 = (unsigned short __user *)((unsigned long)pc & ~1);
225 	for(i = -3 ; i < 6 ; i++) {
226 		unsigned int insn;
227 		if (pc16 ? __get_user(insn, pc16 + i) : __get_user(insn, pc + i)) {
228 			printk(" (Bad address in epc)\n");
229 			break;
230 		}
231 		printk("%c%0*x%c", (i?' ':'<'), pc16 ? 4 : 8, insn, (i?' ':'>'));
232 	}
233 }
234 
235 static void __show_regs(const struct pt_regs *regs)
236 {
237 	const int field = 2 * sizeof(unsigned long);
238 	unsigned int cause = regs->cp0_cause;
239 	int i;
240 
241 	show_regs_print_info(KERN_DEFAULT);
242 
243 	/*
244 	 * Saved main processor registers
245 	 */
246 	for (i = 0; i < 32; ) {
247 		if ((i % 4) == 0)
248 			printk("$%2d   :", i);
249 		if (i == 0)
250 			printk(" %0*lx", field, 0UL);
251 		else if (i == 26 || i == 27)
252 			printk(" %*s", field, "");
253 		else
254 			printk(" %0*lx", field, regs->regs[i]);
255 
256 		i++;
257 		if ((i % 4) == 0)
258 			printk("\n");
259 	}
260 
261 #ifdef CONFIG_CPU_HAS_SMARTMIPS
262 	printk("Acx    : %0*lx\n", field, regs->acx);
263 #endif
264 	printk("Hi    : %0*lx\n", field, regs->hi);
265 	printk("Lo    : %0*lx\n", field, regs->lo);
266 
267 	/*
268 	 * Saved cp0 registers
269 	 */
270 	printk("epc   : %0*lx %pS\n", field, regs->cp0_epc,
271 	       (void *) regs->cp0_epc);
272 	printk("ra    : %0*lx %pS\n", field, regs->regs[31],
273 	       (void *) regs->regs[31]);
274 
275 	printk("Status: %08x	", (uint32_t) regs->cp0_status);
276 
277 	if (cpu_has_3kex) {
278 		if (regs->cp0_status & ST0_KUO)
279 			printk("KUo ");
280 		if (regs->cp0_status & ST0_IEO)
281 			printk("IEo ");
282 		if (regs->cp0_status & ST0_KUP)
283 			printk("KUp ");
284 		if (regs->cp0_status & ST0_IEP)
285 			printk("IEp ");
286 		if (regs->cp0_status & ST0_KUC)
287 			printk("KUc ");
288 		if (regs->cp0_status & ST0_IEC)
289 			printk("IEc ");
290 	} else if (cpu_has_4kex) {
291 		if (regs->cp0_status & ST0_KX)
292 			printk("KX ");
293 		if (regs->cp0_status & ST0_SX)
294 			printk("SX ");
295 		if (regs->cp0_status & ST0_UX)
296 			printk("UX ");
297 		switch (regs->cp0_status & ST0_KSU) {
298 		case KSU_USER:
299 			printk("USER ");
300 			break;
301 		case KSU_SUPERVISOR:
302 			printk("SUPERVISOR ");
303 			break;
304 		case KSU_KERNEL:
305 			printk("KERNEL ");
306 			break;
307 		default:
308 			printk("BAD_MODE ");
309 			break;
310 		}
311 		if (regs->cp0_status & ST0_ERL)
312 			printk("ERL ");
313 		if (regs->cp0_status & ST0_EXL)
314 			printk("EXL ");
315 		if (regs->cp0_status & ST0_IE)
316 			printk("IE ");
317 	}
318 	printk("\n");
319 
320 	printk("Cause : %08x\n", cause);
321 
322 	cause = (cause & CAUSEF_EXCCODE) >> CAUSEB_EXCCODE;
323 	if (1 <= cause && cause <= 5)
324 		printk("BadVA : %0*lx\n", field, regs->cp0_badvaddr);
325 
326 	printk("PrId  : %08x (%s)\n", read_c0_prid(),
327 	       cpu_name_string());
328 }
329 
330 /*
331  * FIXME: really the generic show_regs should take a const pointer argument.
332  */
333 void show_regs(struct pt_regs *regs)
334 {
335 	__show_regs((struct pt_regs *)regs);
336 }
337 
338 void show_registers(struct pt_regs *regs)
339 {
340 	const int field = 2 * sizeof(unsigned long);
341 	mm_segment_t old_fs = get_fs();
342 
343 	__show_regs(regs);
344 	print_modules();
345 	printk("Process %s (pid: %d, threadinfo=%p, task=%p, tls=%0*lx)\n",
346 	       current->comm, current->pid, current_thread_info(), current,
347 	      field, current_thread_info()->tp_value);
348 	if (cpu_has_userlocal) {
349 		unsigned long tls;
350 
351 		tls = read_c0_userlocal();
352 		if (tls != current_thread_info()->tp_value)
353 			printk("*HwTLS: %0*lx\n", field, tls);
354 	}
355 
356 	if (!user_mode(regs))
357 		/* Necessary for getting the correct stack content */
358 		set_fs(KERNEL_DS);
359 	show_stacktrace(current, regs);
360 	show_code((unsigned int __user *) regs->cp0_epc);
361 	printk("\n");
362 	set_fs(old_fs);
363 }
364 
365 static int regs_to_trapnr(struct pt_regs *regs)
366 {
367 	return (regs->cp0_cause >> 2) & 0x1f;
368 }
369 
370 static DEFINE_RAW_SPINLOCK(die_lock);
371 
372 void __noreturn die(const char *str, struct pt_regs *regs)
373 {
374 	static int die_counter;
375 	int sig = SIGSEGV;
376 
377 	oops_enter();
378 
379 	if (notify_die(DIE_OOPS, str, regs, 0, regs_to_trapnr(regs),
380 		       SIGSEGV) == NOTIFY_STOP)
381 		sig = 0;
382 
383 	console_verbose();
384 	raw_spin_lock_irq(&die_lock);
385 	bust_spinlocks(1);
386 
387 	printk("%s[#%d]:\n", str, ++die_counter);
388 	show_registers(regs);
389 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
390 	raw_spin_unlock_irq(&die_lock);
391 
392 	oops_exit();
393 
394 	if (in_interrupt())
395 		panic("Fatal exception in interrupt");
396 
397 	if (panic_on_oops) {
398 		printk(KERN_EMERG "Fatal exception: panic in 5 seconds");
399 		ssleep(5);
400 		panic("Fatal exception");
401 	}
402 
403 	if (regs && kexec_should_crash(current))
404 		crash_kexec(regs);
405 
406 	do_exit(sig);
407 }
408 
409 extern struct exception_table_entry __start___dbe_table[];
410 extern struct exception_table_entry __stop___dbe_table[];
411 
412 __asm__(
413 "	.section	__dbe_table, \"a\"\n"
414 "	.previous			\n");
415 
416 /* Given an address, look for it in the exception tables. */
417 static const struct exception_table_entry *search_dbe_tables(unsigned long addr)
418 {
419 	const struct exception_table_entry *e;
420 
421 	e = search_extable(__start___dbe_table, __stop___dbe_table - 1, addr);
422 	if (!e)
423 		e = search_module_dbetables(addr);
424 	return e;
425 }
426 
427 asmlinkage void do_be(struct pt_regs *regs)
428 {
429 	const int field = 2 * sizeof(unsigned long);
430 	const struct exception_table_entry *fixup = NULL;
431 	int data = regs->cp0_cause & 4;
432 	int action = MIPS_BE_FATAL;
433 	enum ctx_state prev_state;
434 
435 	prev_state = exception_enter();
436 	/* XXX For now.	 Fixme, this searches the wrong table ...  */
437 	if (data && !user_mode(regs))
438 		fixup = search_dbe_tables(exception_epc(regs));
439 
440 	if (fixup)
441 		action = MIPS_BE_FIXUP;
442 
443 	if (board_be_handler)
444 		action = board_be_handler(regs, fixup != NULL);
445 
446 	switch (action) {
447 	case MIPS_BE_DISCARD:
448 		goto out;
449 	case MIPS_BE_FIXUP:
450 		if (fixup) {
451 			regs->cp0_epc = fixup->nextinsn;
452 			goto out;
453 		}
454 		break;
455 	default:
456 		break;
457 	}
458 
459 	/*
460 	 * Assume it would be too dangerous to continue ...
461 	 */
462 	printk(KERN_ALERT "%s bus error, epc == %0*lx, ra == %0*lx\n",
463 	       data ? "Data" : "Instruction",
464 	       field, regs->cp0_epc, field, regs->regs[31]);
465 	if (notify_die(DIE_OOPS, "bus error", regs, 0, regs_to_trapnr(regs),
466 		       SIGBUS) == NOTIFY_STOP)
467 		goto out;
468 
469 	die_if_kernel("Oops", regs);
470 	force_sig(SIGBUS, current);
471 
472 out:
473 	exception_exit(prev_state);
474 }
475 
476 /*
477  * ll/sc, rdhwr, sync emulation
478  */
479 
480 #define OPCODE 0xfc000000
481 #define BASE   0x03e00000
482 #define RT     0x001f0000
483 #define OFFSET 0x0000ffff
484 #define LL     0xc0000000
485 #define SC     0xe0000000
486 #define SPEC0  0x00000000
487 #define SPEC3  0x7c000000
488 #define RD     0x0000f800
489 #define FUNC   0x0000003f
490 #define SYNC   0x0000000f
491 #define RDHWR  0x0000003b
492 
493 /*  microMIPS definitions   */
494 #define MM_POOL32A_FUNC 0xfc00ffff
495 #define MM_RDHWR        0x00006b3c
496 #define MM_RS           0x001f0000
497 #define MM_RT           0x03e00000
498 
499 /*
500  * The ll_bit is cleared by r*_switch.S
501  */
502 
503 unsigned int ll_bit;
504 struct task_struct *ll_task;
505 
506 static inline int simulate_ll(struct pt_regs *regs, unsigned int opcode)
507 {
508 	unsigned long value, __user *vaddr;
509 	long offset;
510 
511 	/*
512 	 * analyse the ll instruction that just caused a ri exception
513 	 * and put the referenced address to addr.
514 	 */
515 
516 	/* sign extend offset */
517 	offset = opcode & OFFSET;
518 	offset <<= 16;
519 	offset >>= 16;
520 
521 	vaddr = (unsigned long __user *)
522 		((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
523 
524 	if ((unsigned long)vaddr & 3)
525 		return SIGBUS;
526 	if (get_user(value, vaddr))
527 		return SIGSEGV;
528 
529 	preempt_disable();
530 
531 	if (ll_task == NULL || ll_task == current) {
532 		ll_bit = 1;
533 	} else {
534 		ll_bit = 0;
535 	}
536 	ll_task = current;
537 
538 	preempt_enable();
539 
540 	regs->regs[(opcode & RT) >> 16] = value;
541 
542 	return 0;
543 }
544 
545 static inline int simulate_sc(struct pt_regs *regs, unsigned int opcode)
546 {
547 	unsigned long __user *vaddr;
548 	unsigned long reg;
549 	long offset;
550 
551 	/*
552 	 * analyse the sc instruction that just caused a ri exception
553 	 * and put the referenced address to addr.
554 	 */
555 
556 	/* sign extend offset */
557 	offset = opcode & OFFSET;
558 	offset <<= 16;
559 	offset >>= 16;
560 
561 	vaddr = (unsigned long __user *)
562 		((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
563 	reg = (opcode & RT) >> 16;
564 
565 	if ((unsigned long)vaddr & 3)
566 		return SIGBUS;
567 
568 	preempt_disable();
569 
570 	if (ll_bit == 0 || ll_task != current) {
571 		regs->regs[reg] = 0;
572 		preempt_enable();
573 		return 0;
574 	}
575 
576 	preempt_enable();
577 
578 	if (put_user(regs->regs[reg], vaddr))
579 		return SIGSEGV;
580 
581 	regs->regs[reg] = 1;
582 
583 	return 0;
584 }
585 
586 /*
587  * ll uses the opcode of lwc0 and sc uses the opcode of swc0.  That is both
588  * opcodes are supposed to result in coprocessor unusable exceptions if
589  * executed on ll/sc-less processors.  That's the theory.  In practice a
590  * few processors such as NEC's VR4100 throw reserved instruction exceptions
591  * instead, so we're doing the emulation thing in both exception handlers.
592  */
593 static int simulate_llsc(struct pt_regs *regs, unsigned int opcode)
594 {
595 	if ((opcode & OPCODE) == LL) {
596 		perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS,
597 				1, regs, 0);
598 		return simulate_ll(regs, opcode);
599 	}
600 	if ((opcode & OPCODE) == SC) {
601 		perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS,
602 				1, regs, 0);
603 		return simulate_sc(regs, opcode);
604 	}
605 
606 	return -1;			/* Must be something else ... */
607 }
608 
609 /*
610  * Simulate trapping 'rdhwr' instructions to provide user accessible
611  * registers not implemented in hardware.
612  */
613 static int simulate_rdhwr(struct pt_regs *regs, int rd, int rt)
614 {
615 	struct thread_info *ti = task_thread_info(current);
616 
617 	perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS,
618 			1, regs, 0);
619 	switch (rd) {
620 	case 0:		/* CPU number */
621 		regs->regs[rt] = smp_processor_id();
622 		return 0;
623 	case 1:		/* SYNCI length */
624 		regs->regs[rt] = min(current_cpu_data.dcache.linesz,
625 				     current_cpu_data.icache.linesz);
626 		return 0;
627 	case 2:		/* Read count register */
628 		regs->regs[rt] = read_c0_count();
629 		return 0;
630 	case 3:		/* Count register resolution */
631 		switch (current_cpu_type()) {
632 		case CPU_20KC:
633 		case CPU_25KF:
634 			regs->regs[rt] = 1;
635 			break;
636 		default:
637 			regs->regs[rt] = 2;
638 		}
639 		return 0;
640 	case 29:
641 		regs->regs[rt] = ti->tp_value;
642 		return 0;
643 	default:
644 		return -1;
645 	}
646 }
647 
648 static int simulate_rdhwr_normal(struct pt_regs *regs, unsigned int opcode)
649 {
650 	if ((opcode & OPCODE) == SPEC3 && (opcode & FUNC) == RDHWR) {
651 		int rd = (opcode & RD) >> 11;
652 		int rt = (opcode & RT) >> 16;
653 
654 		simulate_rdhwr(regs, rd, rt);
655 		return 0;
656 	}
657 
658 	/* Not ours.  */
659 	return -1;
660 }
661 
662 static int simulate_rdhwr_mm(struct pt_regs *regs, unsigned short opcode)
663 {
664 	if ((opcode & MM_POOL32A_FUNC) == MM_RDHWR) {
665 		int rd = (opcode & MM_RS) >> 16;
666 		int rt = (opcode & MM_RT) >> 21;
667 		simulate_rdhwr(regs, rd, rt);
668 		return 0;
669 	}
670 
671 	/* Not ours.  */
672 	return -1;
673 }
674 
675 static int simulate_sync(struct pt_regs *regs, unsigned int opcode)
676 {
677 	if ((opcode & OPCODE) == SPEC0 && (opcode & FUNC) == SYNC) {
678 		perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS,
679 				1, regs, 0);
680 		return 0;
681 	}
682 
683 	return -1;			/* Must be something else ... */
684 }
685 
686 asmlinkage void do_ov(struct pt_regs *regs)
687 {
688 	enum ctx_state prev_state;
689 	siginfo_t info;
690 
691 	prev_state = exception_enter();
692 	die_if_kernel("Integer overflow", regs);
693 
694 	info.si_code = FPE_INTOVF;
695 	info.si_signo = SIGFPE;
696 	info.si_errno = 0;
697 	info.si_addr = (void __user *) regs->cp0_epc;
698 	force_sig_info(SIGFPE, &info, current);
699 	exception_exit(prev_state);
700 }
701 
702 int process_fpemu_return(int sig, void __user *fault_addr, unsigned long fcr31)
703 {
704 	struct siginfo si = { 0 };
705 
706 	switch (sig) {
707 	case 0:
708 		return 0;
709 
710 	case SIGFPE:
711 		si.si_addr = fault_addr;
712 		si.si_signo = sig;
713 		/*
714 		 * Inexact can happen together with Overflow or Underflow.
715 		 * Respect the mask to deliver the correct exception.
716 		 */
717 		fcr31 &= (fcr31 & FPU_CSR_ALL_E) <<
718 			 (ffs(FPU_CSR_ALL_X) - ffs(FPU_CSR_ALL_E));
719 		if (fcr31 & FPU_CSR_INV_X)
720 			si.si_code = FPE_FLTINV;
721 		else if (fcr31 & FPU_CSR_DIV_X)
722 			si.si_code = FPE_FLTDIV;
723 		else if (fcr31 & FPU_CSR_OVF_X)
724 			si.si_code = FPE_FLTOVF;
725 		else if (fcr31 & FPU_CSR_UDF_X)
726 			si.si_code = FPE_FLTUND;
727 		else if (fcr31 & FPU_CSR_INE_X)
728 			si.si_code = FPE_FLTRES;
729 		else
730 			si.si_code = __SI_FAULT;
731 		force_sig_info(sig, &si, current);
732 		return 1;
733 
734 	case SIGBUS:
735 		si.si_addr = fault_addr;
736 		si.si_signo = sig;
737 		si.si_code = BUS_ADRERR;
738 		force_sig_info(sig, &si, current);
739 		return 1;
740 
741 	case SIGSEGV:
742 		si.si_addr = fault_addr;
743 		si.si_signo = sig;
744 		down_read(&current->mm->mmap_sem);
745 		if (find_vma(current->mm, (unsigned long)fault_addr))
746 			si.si_code = SEGV_ACCERR;
747 		else
748 			si.si_code = SEGV_MAPERR;
749 		up_read(&current->mm->mmap_sem);
750 		force_sig_info(sig, &si, current);
751 		return 1;
752 
753 	default:
754 		force_sig(sig, current);
755 		return 1;
756 	}
757 }
758 
759 static int simulate_fp(struct pt_regs *regs, unsigned int opcode,
760 		       unsigned long old_epc, unsigned long old_ra)
761 {
762 	union mips_instruction inst = { .word = opcode };
763 	void __user *fault_addr;
764 	unsigned long fcr31;
765 	int sig;
766 
767 	/* If it's obviously not an FP instruction, skip it */
768 	switch (inst.i_format.opcode) {
769 	case cop1_op:
770 	case cop1x_op:
771 	case lwc1_op:
772 	case ldc1_op:
773 	case swc1_op:
774 	case sdc1_op:
775 		break;
776 
777 	default:
778 		return -1;
779 	}
780 
781 	/*
782 	 * do_ri skipped over the instruction via compute_return_epc, undo
783 	 * that for the FPU emulator.
784 	 */
785 	regs->cp0_epc = old_epc;
786 	regs->regs[31] = old_ra;
787 
788 	/* Save the FP context to struct thread_struct */
789 	lose_fpu(1);
790 
791 	/* Run the emulator */
792 	sig = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1,
793 				       &fault_addr);
794 	fcr31 = current->thread.fpu.fcr31;
795 
796 	/*
797 	 * We can't allow the emulated instruction to leave any of
798 	 * the cause bits set in $fcr31.
799 	 */
800 	current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
801 
802 	/* Restore the hardware register state */
803 	own_fpu(1);
804 
805 	/* Send a signal if required.  */
806 	process_fpemu_return(sig, fault_addr, fcr31);
807 
808 	return 0;
809 }
810 
811 /*
812  * XXX Delayed fp exceptions when doing a lazy ctx switch XXX
813  */
814 asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
815 {
816 	enum ctx_state prev_state;
817 	void __user *fault_addr;
818 	int sig;
819 
820 	prev_state = exception_enter();
821 	if (notify_die(DIE_FP, "FP exception", regs, 0, regs_to_trapnr(regs),
822 		       SIGFPE) == NOTIFY_STOP)
823 		goto out;
824 
825 	/* Clear FCSR.Cause before enabling interrupts */
826 	write_32bit_cp1_register(CP1_STATUS, fcr31 & ~FPU_CSR_ALL_X);
827 	local_irq_enable();
828 
829 	die_if_kernel("FP exception in kernel code", regs);
830 
831 	if (fcr31 & FPU_CSR_UNI_X) {
832 		/*
833 		 * Unimplemented operation exception.  If we've got the full
834 		 * software emulator on-board, let's use it...
835 		 *
836 		 * Force FPU to dump state into task/thread context.  We're
837 		 * moving a lot of data here for what is probably a single
838 		 * instruction, but the alternative is to pre-decode the FP
839 		 * register operands before invoking the emulator, which seems
840 		 * a bit extreme for what should be an infrequent event.
841 		 */
842 		/* Ensure 'resume' not overwrite saved fp context again. */
843 		lose_fpu(1);
844 
845 		/* Run the emulator */
846 		sig = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1,
847 					       &fault_addr);
848 		fcr31 = current->thread.fpu.fcr31;
849 
850 		/*
851 		 * We can't allow the emulated instruction to leave any of
852 		 * the cause bits set in $fcr31.
853 		 */
854 		current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
855 
856 		/* Restore the hardware register state */
857 		own_fpu(1);	/* Using the FPU again.	 */
858 	} else {
859 		sig = SIGFPE;
860 		fault_addr = (void __user *) regs->cp0_epc;
861 	}
862 
863 	/* Send a signal if required.  */
864 	process_fpemu_return(sig, fault_addr, fcr31);
865 
866 out:
867 	exception_exit(prev_state);
868 }
869 
870 void do_trap_or_bp(struct pt_regs *regs, unsigned int code,
871 	const char *str)
872 {
873 	siginfo_t info;
874 	char b[40];
875 
876 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
877 	if (kgdb_ll_trap(DIE_TRAP, str, regs, code, regs_to_trapnr(regs), SIGTRAP) == NOTIFY_STOP)
878 		return;
879 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
880 
881 	if (notify_die(DIE_TRAP, str, regs, code, regs_to_trapnr(regs),
882 		       SIGTRAP) == NOTIFY_STOP)
883 		return;
884 
885 	/*
886 	 * A short test says that IRIX 5.3 sends SIGTRAP for all trap
887 	 * insns, even for trap and break codes that indicate arithmetic
888 	 * failures.  Weird ...
889 	 * But should we continue the brokenness???  --macro
890 	 */
891 	switch (code) {
892 	case BRK_OVERFLOW:
893 	case BRK_DIVZERO:
894 		scnprintf(b, sizeof(b), "%s instruction in kernel code", str);
895 		die_if_kernel(b, regs);
896 		if (code == BRK_DIVZERO)
897 			info.si_code = FPE_INTDIV;
898 		else
899 			info.si_code = FPE_INTOVF;
900 		info.si_signo = SIGFPE;
901 		info.si_errno = 0;
902 		info.si_addr = (void __user *) regs->cp0_epc;
903 		force_sig_info(SIGFPE, &info, current);
904 		break;
905 	case BRK_BUG:
906 		die_if_kernel("Kernel bug detected", regs);
907 		force_sig(SIGTRAP, current);
908 		break;
909 	case BRK_MEMU:
910 		/*
911 		 * This breakpoint code is used by the FPU emulator to retake
912 		 * control of the CPU after executing the instruction from the
913 		 * delay slot of an emulated branch.
914 		 *
915 		 * Terminate if exception was recognized as a delay slot return
916 		 * otherwise handle as normal.
917 		 */
918 		if (do_dsemulret(regs))
919 			return;
920 
921 		die_if_kernel("Math emu break/trap", regs);
922 		force_sig(SIGTRAP, current);
923 		break;
924 	default:
925 		scnprintf(b, sizeof(b), "%s instruction in kernel code", str);
926 		die_if_kernel(b, regs);
927 		force_sig(SIGTRAP, current);
928 	}
929 }
930 
931 asmlinkage void do_bp(struct pt_regs *regs)
932 {
933 	unsigned long epc = msk_isa16_mode(exception_epc(regs));
934 	unsigned int opcode, bcode;
935 	enum ctx_state prev_state;
936 	mm_segment_t seg;
937 
938 	seg = get_fs();
939 	if (!user_mode(regs))
940 		set_fs(KERNEL_DS);
941 
942 	prev_state = exception_enter();
943 	if (get_isa16_mode(regs->cp0_epc)) {
944 		u16 instr[2];
945 
946 		if (__get_user(instr[0], (u16 __user *)epc))
947 			goto out_sigsegv;
948 
949 		if (!cpu_has_mmips) {
950 			/* MIPS16e mode */
951 			bcode = (instr[0] >> 5) & 0x3f;
952 		} else if (mm_insn_16bit(instr[0])) {
953 			/* 16-bit microMIPS BREAK */
954 			bcode = instr[0] & 0xf;
955 		} else {
956 			/* 32-bit microMIPS BREAK */
957 			if (__get_user(instr[1], (u16 __user *)(epc + 2)))
958 				goto out_sigsegv;
959 			opcode = (instr[0] << 16) | instr[1];
960 			bcode = (opcode >> 6) & ((1 << 20) - 1);
961 		}
962 	} else {
963 		if (__get_user(opcode, (unsigned int __user *)epc))
964 			goto out_sigsegv;
965 		bcode = (opcode >> 6) & ((1 << 20) - 1);
966 	}
967 
968 	/*
969 	 * There is the ancient bug in the MIPS assemblers that the break
970 	 * code starts left to bit 16 instead to bit 6 in the opcode.
971 	 * Gas is bug-compatible, but not always, grrr...
972 	 * We handle both cases with a simple heuristics.  --macro
973 	 */
974 	if (bcode >= (1 << 10))
975 		bcode = ((bcode & ((1 << 10) - 1)) << 10) | (bcode >> 10);
976 
977 	/*
978 	 * notify the kprobe handlers, if instruction is likely to
979 	 * pertain to them.
980 	 */
981 	switch (bcode) {
982 	case BRK_KPROBE_BP:
983 		if (notify_die(DIE_BREAK, "debug", regs, bcode,
984 			       regs_to_trapnr(regs), SIGTRAP) == NOTIFY_STOP)
985 			goto out;
986 		else
987 			break;
988 	case BRK_KPROBE_SSTEPBP:
989 		if (notify_die(DIE_SSTEPBP, "single_step", regs, bcode,
990 			       regs_to_trapnr(regs), SIGTRAP) == NOTIFY_STOP)
991 			goto out;
992 		else
993 			break;
994 	default:
995 		break;
996 	}
997 
998 	do_trap_or_bp(regs, bcode, "Break");
999 
1000 out:
1001 	set_fs(seg);
1002 	exception_exit(prev_state);
1003 	return;
1004 
1005 out_sigsegv:
1006 	force_sig(SIGSEGV, current);
1007 	goto out;
1008 }
1009 
1010 asmlinkage void do_tr(struct pt_regs *regs)
1011 {
1012 	u32 opcode, tcode = 0;
1013 	enum ctx_state prev_state;
1014 	u16 instr[2];
1015 	mm_segment_t seg;
1016 	unsigned long epc = msk_isa16_mode(exception_epc(regs));
1017 
1018 	seg = get_fs();
1019 	if (!user_mode(regs))
1020 		set_fs(get_ds());
1021 
1022 	prev_state = exception_enter();
1023 	if (get_isa16_mode(regs->cp0_epc)) {
1024 		if (__get_user(instr[0], (u16 __user *)(epc + 0)) ||
1025 		    __get_user(instr[1], (u16 __user *)(epc + 2)))
1026 			goto out_sigsegv;
1027 		opcode = (instr[0] << 16) | instr[1];
1028 		/* Immediate versions don't provide a code.  */
1029 		if (!(opcode & OPCODE))
1030 			tcode = (opcode >> 12) & ((1 << 4) - 1);
1031 	} else {
1032 		if (__get_user(opcode, (u32 __user *)epc))
1033 			goto out_sigsegv;
1034 		/* Immediate versions don't provide a code.  */
1035 		if (!(opcode & OPCODE))
1036 			tcode = (opcode >> 6) & ((1 << 10) - 1);
1037 	}
1038 
1039 	do_trap_or_bp(regs, tcode, "Trap");
1040 
1041 out:
1042 	set_fs(seg);
1043 	exception_exit(prev_state);
1044 	return;
1045 
1046 out_sigsegv:
1047 	force_sig(SIGSEGV, current);
1048 	goto out;
1049 }
1050 
1051 asmlinkage void do_ri(struct pt_regs *regs)
1052 {
1053 	unsigned int __user *epc = (unsigned int __user *)exception_epc(regs);
1054 	unsigned long old_epc = regs->cp0_epc;
1055 	unsigned long old31 = regs->regs[31];
1056 	enum ctx_state prev_state;
1057 	unsigned int opcode = 0;
1058 	int status = -1;
1059 
1060 	/*
1061 	 * Avoid any kernel code. Just emulate the R2 instruction
1062 	 * as quickly as possible.
1063 	 */
1064 	if (mipsr2_emulation && cpu_has_mips_r6 &&
1065 	    likely(user_mode(regs)) &&
1066 	    likely(get_user(opcode, epc) >= 0)) {
1067 		unsigned long fcr31 = 0;
1068 
1069 		status = mipsr2_decoder(regs, opcode, &fcr31);
1070 		switch (status) {
1071 		case 0:
1072 		case SIGEMT:
1073 			task_thread_info(current)->r2_emul_return = 1;
1074 			return;
1075 		case SIGILL:
1076 			goto no_r2_instr;
1077 		default:
1078 			process_fpemu_return(status,
1079 					     &current->thread.cp0_baduaddr,
1080 					     fcr31);
1081 			task_thread_info(current)->r2_emul_return = 1;
1082 			return;
1083 		}
1084 	}
1085 
1086 no_r2_instr:
1087 
1088 	prev_state = exception_enter();
1089 
1090 	if (notify_die(DIE_RI, "RI Fault", regs, 0, regs_to_trapnr(regs),
1091 		       SIGILL) == NOTIFY_STOP)
1092 		goto out;
1093 
1094 	die_if_kernel("Reserved instruction in kernel code", regs);
1095 
1096 	if (unlikely(compute_return_epc(regs) < 0))
1097 		goto out;
1098 
1099 	if (get_isa16_mode(regs->cp0_epc)) {
1100 		unsigned short mmop[2] = { 0 };
1101 
1102 		if (unlikely(get_user(mmop[0], epc) < 0))
1103 			status = SIGSEGV;
1104 		if (unlikely(get_user(mmop[1], epc) < 0))
1105 			status = SIGSEGV;
1106 		opcode = (mmop[0] << 16) | mmop[1];
1107 
1108 		if (status < 0)
1109 			status = simulate_rdhwr_mm(regs, opcode);
1110 	} else {
1111 		if (unlikely(get_user(opcode, epc) < 0))
1112 			status = SIGSEGV;
1113 
1114 		if (!cpu_has_llsc && status < 0)
1115 			status = simulate_llsc(regs, opcode);
1116 
1117 		if (status < 0)
1118 			status = simulate_rdhwr_normal(regs, opcode);
1119 
1120 		if (status < 0)
1121 			status = simulate_sync(regs, opcode);
1122 
1123 		if (status < 0)
1124 			status = simulate_fp(regs, opcode, old_epc, old31);
1125 	}
1126 
1127 	if (status < 0)
1128 		status = SIGILL;
1129 
1130 	if (unlikely(status > 0)) {
1131 		regs->cp0_epc = old_epc;		/* Undo skip-over.  */
1132 		regs->regs[31] = old31;
1133 		force_sig(status, current);
1134 	}
1135 
1136 out:
1137 	exception_exit(prev_state);
1138 }
1139 
1140 /*
1141  * MIPS MT processors may have fewer FPU contexts than CPU threads. If we've
1142  * emulated more than some threshold number of instructions, force migration to
1143  * a "CPU" that has FP support.
1144  */
1145 static void mt_ase_fp_affinity(void)
1146 {
1147 #ifdef CONFIG_MIPS_MT_FPAFF
1148 	if (mt_fpemul_threshold > 0 &&
1149 	     ((current->thread.emulated_fp++ > mt_fpemul_threshold))) {
1150 		/*
1151 		 * If there's no FPU present, or if the application has already
1152 		 * restricted the allowed set to exclude any CPUs with FPUs,
1153 		 * we'll skip the procedure.
1154 		 */
1155 		if (cpumask_intersects(&current->cpus_allowed, &mt_fpu_cpumask)) {
1156 			cpumask_t tmask;
1157 
1158 			current->thread.user_cpus_allowed
1159 				= current->cpus_allowed;
1160 			cpumask_and(&tmask, &current->cpus_allowed,
1161 				    &mt_fpu_cpumask);
1162 			set_cpus_allowed_ptr(current, &tmask);
1163 			set_thread_flag(TIF_FPUBOUND);
1164 		}
1165 	}
1166 #endif /* CONFIG_MIPS_MT_FPAFF */
1167 }
1168 
1169 /*
1170  * No lock; only written during early bootup by CPU 0.
1171  */
1172 static RAW_NOTIFIER_HEAD(cu2_chain);
1173 
1174 int __ref register_cu2_notifier(struct notifier_block *nb)
1175 {
1176 	return raw_notifier_chain_register(&cu2_chain, nb);
1177 }
1178 
1179 int cu2_notifier_call_chain(unsigned long val, void *v)
1180 {
1181 	return raw_notifier_call_chain(&cu2_chain, val, v);
1182 }
1183 
1184 static int default_cu2_call(struct notifier_block *nfb, unsigned long action,
1185 	void *data)
1186 {
1187 	struct pt_regs *regs = data;
1188 
1189 	die_if_kernel("COP2: Unhandled kernel unaligned access or invalid "
1190 			      "instruction", regs);
1191 	force_sig(SIGILL, current);
1192 
1193 	return NOTIFY_OK;
1194 }
1195 
1196 static int wait_on_fp_mode_switch(atomic_t *p)
1197 {
1198 	/*
1199 	 * The FP mode for this task is currently being switched. That may
1200 	 * involve modifications to the format of this tasks FP context which
1201 	 * make it unsafe to proceed with execution for the moment. Instead,
1202 	 * schedule some other task.
1203 	 */
1204 	schedule();
1205 	return 0;
1206 }
1207 
1208 static int enable_restore_fp_context(int msa)
1209 {
1210 	int err, was_fpu_owner, prior_msa;
1211 
1212 	/*
1213 	 * If an FP mode switch is currently underway, wait for it to
1214 	 * complete before proceeding.
1215 	 */
1216 	wait_on_atomic_t(&current->mm->context.fp_mode_switching,
1217 			 wait_on_fp_mode_switch, TASK_KILLABLE);
1218 
1219 	if (!used_math()) {
1220 		/* First time FP context user. */
1221 		preempt_disable();
1222 		err = init_fpu();
1223 		if (msa && !err) {
1224 			enable_msa();
1225 			_init_msa_upper();
1226 			set_thread_flag(TIF_USEDMSA);
1227 			set_thread_flag(TIF_MSA_CTX_LIVE);
1228 		}
1229 		preempt_enable();
1230 		if (!err)
1231 			set_used_math();
1232 		return err;
1233 	}
1234 
1235 	/*
1236 	 * This task has formerly used the FP context.
1237 	 *
1238 	 * If this thread has no live MSA vector context then we can simply
1239 	 * restore the scalar FP context. If it has live MSA vector context
1240 	 * (that is, it has or may have used MSA since last performing a
1241 	 * function call) then we'll need to restore the vector context. This
1242 	 * applies even if we're currently only executing a scalar FP
1243 	 * instruction. This is because if we were to later execute an MSA
1244 	 * instruction then we'd either have to:
1245 	 *
1246 	 *  - Restore the vector context & clobber any registers modified by
1247 	 *    scalar FP instructions between now & then.
1248 	 *
1249 	 * or
1250 	 *
1251 	 *  - Not restore the vector context & lose the most significant bits
1252 	 *    of all vector registers.
1253 	 *
1254 	 * Neither of those options is acceptable. We cannot restore the least
1255 	 * significant bits of the registers now & only restore the most
1256 	 * significant bits later because the most significant bits of any
1257 	 * vector registers whose aliased FP register is modified now will have
1258 	 * been zeroed. We'd have no way to know that when restoring the vector
1259 	 * context & thus may load an outdated value for the most significant
1260 	 * bits of a vector register.
1261 	 */
1262 	if (!msa && !thread_msa_context_live())
1263 		return own_fpu(1);
1264 
1265 	/*
1266 	 * This task is using or has previously used MSA. Thus we require
1267 	 * that Status.FR == 1.
1268 	 */
1269 	preempt_disable();
1270 	was_fpu_owner = is_fpu_owner();
1271 	err = own_fpu_inatomic(0);
1272 	if (err)
1273 		goto out;
1274 
1275 	enable_msa();
1276 	write_msa_csr(current->thread.fpu.msacsr);
1277 	set_thread_flag(TIF_USEDMSA);
1278 
1279 	/*
1280 	 * If this is the first time that the task is using MSA and it has
1281 	 * previously used scalar FP in this time slice then we already nave
1282 	 * FP context which we shouldn't clobber. We do however need to clear
1283 	 * the upper 64b of each vector register so that this task has no
1284 	 * opportunity to see data left behind by another.
1285 	 */
1286 	prior_msa = test_and_set_thread_flag(TIF_MSA_CTX_LIVE);
1287 	if (!prior_msa && was_fpu_owner) {
1288 		_init_msa_upper();
1289 
1290 		goto out;
1291 	}
1292 
1293 	if (!prior_msa) {
1294 		/*
1295 		 * Restore the least significant 64b of each vector register
1296 		 * from the existing scalar FP context.
1297 		 */
1298 		_restore_fp(current);
1299 
1300 		/*
1301 		 * The task has not formerly used MSA, so clear the upper 64b
1302 		 * of each vector register such that it cannot see data left
1303 		 * behind by another task.
1304 		 */
1305 		_init_msa_upper();
1306 	} else {
1307 		/* We need to restore the vector context. */
1308 		restore_msa(current);
1309 
1310 		/* Restore the scalar FP control & status register */
1311 		if (!was_fpu_owner)
1312 			write_32bit_cp1_register(CP1_STATUS,
1313 						 current->thread.fpu.fcr31);
1314 	}
1315 
1316 out:
1317 	preempt_enable();
1318 
1319 	return 0;
1320 }
1321 
1322 asmlinkage void do_cpu(struct pt_regs *regs)
1323 {
1324 	enum ctx_state prev_state;
1325 	unsigned int __user *epc;
1326 	unsigned long old_epc, old31;
1327 	void __user *fault_addr;
1328 	unsigned int opcode;
1329 	unsigned long fcr31;
1330 	unsigned int cpid;
1331 	int status, err;
1332 	unsigned long __maybe_unused flags;
1333 	int sig;
1334 
1335 	prev_state = exception_enter();
1336 	cpid = (regs->cp0_cause >> CAUSEB_CE) & 3;
1337 
1338 	if (cpid != 2)
1339 		die_if_kernel("do_cpu invoked from kernel context!", regs);
1340 
1341 	switch (cpid) {
1342 	case 0:
1343 		epc = (unsigned int __user *)exception_epc(regs);
1344 		old_epc = regs->cp0_epc;
1345 		old31 = regs->regs[31];
1346 		opcode = 0;
1347 		status = -1;
1348 
1349 		if (unlikely(compute_return_epc(regs) < 0))
1350 			break;
1351 
1352 		if (get_isa16_mode(regs->cp0_epc)) {
1353 			unsigned short mmop[2] = { 0 };
1354 
1355 			if (unlikely(get_user(mmop[0], epc) < 0))
1356 				status = SIGSEGV;
1357 			if (unlikely(get_user(mmop[1], epc) < 0))
1358 				status = SIGSEGV;
1359 			opcode = (mmop[0] << 16) | mmop[1];
1360 
1361 			if (status < 0)
1362 				status = simulate_rdhwr_mm(regs, opcode);
1363 		} else {
1364 			if (unlikely(get_user(opcode, epc) < 0))
1365 				status = SIGSEGV;
1366 
1367 			if (!cpu_has_llsc && status < 0)
1368 				status = simulate_llsc(regs, opcode);
1369 
1370 			if (status < 0)
1371 				status = simulate_rdhwr_normal(regs, opcode);
1372 		}
1373 
1374 		if (status < 0)
1375 			status = SIGILL;
1376 
1377 		if (unlikely(status > 0)) {
1378 			regs->cp0_epc = old_epc;	/* Undo skip-over.  */
1379 			regs->regs[31] = old31;
1380 			force_sig(status, current);
1381 		}
1382 
1383 		break;
1384 
1385 	case 3:
1386 		/*
1387 		 * The COP3 opcode space and consequently the CP0.Status.CU3
1388 		 * bit and the CP0.Cause.CE=3 encoding have been removed as
1389 		 * of the MIPS III ISA.  From the MIPS IV and MIPS32r2 ISAs
1390 		 * up the space has been reused for COP1X instructions, that
1391 		 * are enabled by the CP0.Status.CU1 bit and consequently
1392 		 * use the CP0.Cause.CE=1 encoding for Coprocessor Unusable
1393 		 * exceptions.  Some FPU-less processors that implement one
1394 		 * of these ISAs however use this code erroneously for COP1X
1395 		 * instructions.  Therefore we redirect this trap to the FP
1396 		 * emulator too.
1397 		 */
1398 		if (raw_cpu_has_fpu || !cpu_has_mips_4_5_64_r2_r6) {
1399 			force_sig(SIGILL, current);
1400 			break;
1401 		}
1402 		/* Fall through.  */
1403 
1404 	case 1:
1405 		err = enable_restore_fp_context(0);
1406 
1407 		if (raw_cpu_has_fpu && !err)
1408 			break;
1409 
1410 		sig = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 0,
1411 					       &fault_addr);
1412 		fcr31 = current->thread.fpu.fcr31;
1413 
1414 		/*
1415 		 * We can't allow the emulated instruction to leave
1416 		 * any of the cause bits set in $fcr31.
1417 		 */
1418 		current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
1419 
1420 		/* Send a signal if required.  */
1421 		if (!process_fpemu_return(sig, fault_addr, fcr31) && !err)
1422 			mt_ase_fp_affinity();
1423 
1424 		break;
1425 
1426 	case 2:
1427 		raw_notifier_call_chain(&cu2_chain, CU2_EXCEPTION, regs);
1428 		break;
1429 	}
1430 
1431 	exception_exit(prev_state);
1432 }
1433 
1434 asmlinkage void do_msa_fpe(struct pt_regs *regs, unsigned int msacsr)
1435 {
1436 	enum ctx_state prev_state;
1437 
1438 	prev_state = exception_enter();
1439 	if (notify_die(DIE_MSAFP, "MSA FP exception", regs, 0,
1440 		       regs_to_trapnr(regs), SIGFPE) == NOTIFY_STOP)
1441 		goto out;
1442 
1443 	/* Clear MSACSR.Cause before enabling interrupts */
1444 	write_msa_csr(msacsr & ~MSA_CSR_CAUSEF);
1445 	local_irq_enable();
1446 
1447 	die_if_kernel("do_msa_fpe invoked from kernel context!", regs);
1448 	force_sig(SIGFPE, current);
1449 out:
1450 	exception_exit(prev_state);
1451 }
1452 
1453 asmlinkage void do_msa(struct pt_regs *regs)
1454 {
1455 	enum ctx_state prev_state;
1456 	int err;
1457 
1458 	prev_state = exception_enter();
1459 
1460 	if (!cpu_has_msa || test_thread_flag(TIF_32BIT_FPREGS)) {
1461 		force_sig(SIGILL, current);
1462 		goto out;
1463 	}
1464 
1465 	die_if_kernel("do_msa invoked from kernel context!", regs);
1466 
1467 	err = enable_restore_fp_context(1);
1468 	if (err)
1469 		force_sig(SIGILL, current);
1470 out:
1471 	exception_exit(prev_state);
1472 }
1473 
1474 asmlinkage void do_mdmx(struct pt_regs *regs)
1475 {
1476 	enum ctx_state prev_state;
1477 
1478 	prev_state = exception_enter();
1479 	force_sig(SIGILL, current);
1480 	exception_exit(prev_state);
1481 }
1482 
1483 /*
1484  * Called with interrupts disabled.
1485  */
1486 asmlinkage void do_watch(struct pt_regs *regs)
1487 {
1488 	enum ctx_state prev_state;
1489 	u32 cause;
1490 
1491 	prev_state = exception_enter();
1492 	/*
1493 	 * Clear WP (bit 22) bit of cause register so we don't loop
1494 	 * forever.
1495 	 */
1496 	cause = read_c0_cause();
1497 	cause &= ~(1 << 22);
1498 	write_c0_cause(cause);
1499 
1500 	/*
1501 	 * If the current thread has the watch registers loaded, save
1502 	 * their values and send SIGTRAP.  Otherwise another thread
1503 	 * left the registers set, clear them and continue.
1504 	 */
1505 	if (test_tsk_thread_flag(current, TIF_LOAD_WATCH)) {
1506 		mips_read_watch_registers();
1507 		local_irq_enable();
1508 		force_sig(SIGTRAP, current);
1509 	} else {
1510 		mips_clear_watch_registers();
1511 		local_irq_enable();
1512 	}
1513 	exception_exit(prev_state);
1514 }
1515 
1516 asmlinkage void do_mcheck(struct pt_regs *regs)
1517 {
1518 	const int field = 2 * sizeof(unsigned long);
1519 	int multi_match = regs->cp0_status & ST0_TS;
1520 	enum ctx_state prev_state;
1521 
1522 	prev_state = exception_enter();
1523 	show_regs(regs);
1524 
1525 	if (multi_match) {
1526 		pr_err("Index	: %0x\n", read_c0_index());
1527 		pr_err("Pagemask: %0x\n", read_c0_pagemask());
1528 		pr_err("EntryHi : %0*lx\n", field, read_c0_entryhi());
1529 		pr_err("EntryLo0: %0*lx\n", field, read_c0_entrylo0());
1530 		pr_err("EntryLo1: %0*lx\n", field, read_c0_entrylo1());
1531 		pr_err("Wired   : %0x\n", read_c0_wired());
1532 		pr_err("Pagegrain: %0x\n", read_c0_pagegrain());
1533 		if (cpu_has_htw) {
1534 			pr_err("PWField : %0*lx\n", field, read_c0_pwfield());
1535 			pr_err("PWSize  : %0*lx\n", field, read_c0_pwsize());
1536 			pr_err("PWCtl   : %0x\n", read_c0_pwctl());
1537 		}
1538 		pr_err("\n");
1539 		dump_tlb_all();
1540 	}
1541 
1542 	show_code((unsigned int __user *) regs->cp0_epc);
1543 
1544 	/*
1545 	 * Some chips may have other causes of machine check (e.g. SB1
1546 	 * graduation timer)
1547 	 */
1548 	panic("Caught Machine Check exception - %scaused by multiple "
1549 	      "matching entries in the TLB.",
1550 	      (multi_match) ? "" : "not ");
1551 }
1552 
1553 asmlinkage void do_mt(struct pt_regs *regs)
1554 {
1555 	int subcode;
1556 
1557 	subcode = (read_vpe_c0_vpecontrol() & VPECONTROL_EXCPT)
1558 			>> VPECONTROL_EXCPT_SHIFT;
1559 	switch (subcode) {
1560 	case 0:
1561 		printk(KERN_DEBUG "Thread Underflow\n");
1562 		break;
1563 	case 1:
1564 		printk(KERN_DEBUG "Thread Overflow\n");
1565 		break;
1566 	case 2:
1567 		printk(KERN_DEBUG "Invalid YIELD Qualifier\n");
1568 		break;
1569 	case 3:
1570 		printk(KERN_DEBUG "Gating Storage Exception\n");
1571 		break;
1572 	case 4:
1573 		printk(KERN_DEBUG "YIELD Scheduler Exception\n");
1574 		break;
1575 	case 5:
1576 		printk(KERN_DEBUG "Gating Storage Scheduler Exception\n");
1577 		break;
1578 	default:
1579 		printk(KERN_DEBUG "*** UNKNOWN THREAD EXCEPTION %d ***\n",
1580 			subcode);
1581 		break;
1582 	}
1583 	die_if_kernel("MIPS MT Thread exception in kernel", regs);
1584 
1585 	force_sig(SIGILL, current);
1586 }
1587 
1588 
1589 asmlinkage void do_dsp(struct pt_regs *regs)
1590 {
1591 	if (cpu_has_dsp)
1592 		panic("Unexpected DSP exception");
1593 
1594 	force_sig(SIGILL, current);
1595 }
1596 
1597 asmlinkage void do_reserved(struct pt_regs *regs)
1598 {
1599 	/*
1600 	 * Game over - no way to handle this if it ever occurs.	 Most probably
1601 	 * caused by a new unknown cpu type or after another deadly
1602 	 * hard/software error.
1603 	 */
1604 	show_regs(regs);
1605 	panic("Caught reserved exception %ld - should not happen.",
1606 	      (regs->cp0_cause & 0x7f) >> 2);
1607 }
1608 
1609 static int __initdata l1parity = 1;
1610 static int __init nol1parity(char *s)
1611 {
1612 	l1parity = 0;
1613 	return 1;
1614 }
1615 __setup("nol1par", nol1parity);
1616 static int __initdata l2parity = 1;
1617 static int __init nol2parity(char *s)
1618 {
1619 	l2parity = 0;
1620 	return 1;
1621 }
1622 __setup("nol2par", nol2parity);
1623 
1624 /*
1625  * Some MIPS CPUs can enable/disable for cache parity detection, but do
1626  * it different ways.
1627  */
1628 static inline void parity_protection_init(void)
1629 {
1630 	switch (current_cpu_type()) {
1631 	case CPU_24K:
1632 	case CPU_34K:
1633 	case CPU_74K:
1634 	case CPU_1004K:
1635 	case CPU_1074K:
1636 	case CPU_INTERAPTIV:
1637 	case CPU_PROAPTIV:
1638 	case CPU_P5600:
1639 	case CPU_QEMU_GENERIC:
1640 		{
1641 #define ERRCTL_PE	0x80000000
1642 #define ERRCTL_L2P	0x00800000
1643 			unsigned long errctl;
1644 			unsigned int l1parity_present, l2parity_present;
1645 
1646 			errctl = read_c0_ecc();
1647 			errctl &= ~(ERRCTL_PE|ERRCTL_L2P);
1648 
1649 			/* probe L1 parity support */
1650 			write_c0_ecc(errctl | ERRCTL_PE);
1651 			back_to_back_c0_hazard();
1652 			l1parity_present = (read_c0_ecc() & ERRCTL_PE);
1653 
1654 			/* probe L2 parity support */
1655 			write_c0_ecc(errctl|ERRCTL_L2P);
1656 			back_to_back_c0_hazard();
1657 			l2parity_present = (read_c0_ecc() & ERRCTL_L2P);
1658 
1659 			if (l1parity_present && l2parity_present) {
1660 				if (l1parity)
1661 					errctl |= ERRCTL_PE;
1662 				if (l1parity ^ l2parity)
1663 					errctl |= ERRCTL_L2P;
1664 			} else if (l1parity_present) {
1665 				if (l1parity)
1666 					errctl |= ERRCTL_PE;
1667 			} else if (l2parity_present) {
1668 				if (l2parity)
1669 					errctl |= ERRCTL_L2P;
1670 			} else {
1671 				/* No parity available */
1672 			}
1673 
1674 			printk(KERN_INFO "Writing ErrCtl register=%08lx\n", errctl);
1675 
1676 			write_c0_ecc(errctl);
1677 			back_to_back_c0_hazard();
1678 			errctl = read_c0_ecc();
1679 			printk(KERN_INFO "Readback ErrCtl register=%08lx\n", errctl);
1680 
1681 			if (l1parity_present)
1682 				printk(KERN_INFO "Cache parity protection %sabled\n",
1683 				       (errctl & ERRCTL_PE) ? "en" : "dis");
1684 
1685 			if (l2parity_present) {
1686 				if (l1parity_present && l1parity)
1687 					errctl ^= ERRCTL_L2P;
1688 				printk(KERN_INFO "L2 cache parity protection %sabled\n",
1689 				       (errctl & ERRCTL_L2P) ? "en" : "dis");
1690 			}
1691 		}
1692 		break;
1693 
1694 	case CPU_5KC:
1695 	case CPU_5KE:
1696 	case CPU_LOONGSON1:
1697 		write_c0_ecc(0x80000000);
1698 		back_to_back_c0_hazard();
1699 		/* Set the PE bit (bit 31) in the c0_errctl register. */
1700 		printk(KERN_INFO "Cache parity protection %sabled\n",
1701 		       (read_c0_ecc() & 0x80000000) ? "en" : "dis");
1702 		break;
1703 	case CPU_20KC:
1704 	case CPU_25KF:
1705 		/* Clear the DE bit (bit 16) in the c0_status register. */
1706 		printk(KERN_INFO "Enable cache parity protection for "
1707 		       "MIPS 20KC/25KF CPUs.\n");
1708 		clear_c0_status(ST0_DE);
1709 		break;
1710 	default:
1711 		break;
1712 	}
1713 }
1714 
1715 asmlinkage void cache_parity_error(void)
1716 {
1717 	const int field = 2 * sizeof(unsigned long);
1718 	unsigned int reg_val;
1719 
1720 	/* For the moment, report the problem and hang. */
1721 	printk("Cache error exception:\n");
1722 	printk("cp0_errorepc == %0*lx\n", field, read_c0_errorepc());
1723 	reg_val = read_c0_cacheerr();
1724 	printk("c0_cacheerr == %08x\n", reg_val);
1725 
1726 	printk("Decoded c0_cacheerr: %s cache fault in %s reference.\n",
1727 	       reg_val & (1<<30) ? "secondary" : "primary",
1728 	       reg_val & (1<<31) ? "data" : "insn");
1729 	if ((cpu_has_mips_r2_r6) &&
1730 	    ((current_cpu_data.processor_id & 0xff0000) == PRID_COMP_MIPS)) {
1731 		pr_err("Error bits: %s%s%s%s%s%s%s%s\n",
1732 			reg_val & (1<<29) ? "ED " : "",
1733 			reg_val & (1<<28) ? "ET " : "",
1734 			reg_val & (1<<27) ? "ES " : "",
1735 			reg_val & (1<<26) ? "EE " : "",
1736 			reg_val & (1<<25) ? "EB " : "",
1737 			reg_val & (1<<24) ? "EI " : "",
1738 			reg_val & (1<<23) ? "E1 " : "",
1739 			reg_val & (1<<22) ? "E0 " : "");
1740 	} else {
1741 		pr_err("Error bits: %s%s%s%s%s%s%s\n",
1742 			reg_val & (1<<29) ? "ED " : "",
1743 			reg_val & (1<<28) ? "ET " : "",
1744 			reg_val & (1<<26) ? "EE " : "",
1745 			reg_val & (1<<25) ? "EB " : "",
1746 			reg_val & (1<<24) ? "EI " : "",
1747 			reg_val & (1<<23) ? "E1 " : "",
1748 			reg_val & (1<<22) ? "E0 " : "");
1749 	}
1750 	printk("IDX: 0x%08x\n", reg_val & ((1<<22)-1));
1751 
1752 #if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
1753 	if (reg_val & (1<<22))
1754 		printk("DErrAddr0: 0x%0*lx\n", field, read_c0_derraddr0());
1755 
1756 	if (reg_val & (1<<23))
1757 		printk("DErrAddr1: 0x%0*lx\n", field, read_c0_derraddr1());
1758 #endif
1759 
1760 	panic("Can't handle the cache error!");
1761 }
1762 
1763 asmlinkage void do_ftlb(void)
1764 {
1765 	const int field = 2 * sizeof(unsigned long);
1766 	unsigned int reg_val;
1767 
1768 	/* For the moment, report the problem and hang. */
1769 	if ((cpu_has_mips_r2_r6) &&
1770 	    ((current_cpu_data.processor_id & 0xff0000) == PRID_COMP_MIPS)) {
1771 		pr_err("FTLB error exception, cp0_ecc=0x%08x:\n",
1772 		       read_c0_ecc());
1773 		pr_err("cp0_errorepc == %0*lx\n", field, read_c0_errorepc());
1774 		reg_val = read_c0_cacheerr();
1775 		pr_err("c0_cacheerr == %08x\n", reg_val);
1776 
1777 		if ((reg_val & 0xc0000000) == 0xc0000000) {
1778 			pr_err("Decoded c0_cacheerr: FTLB parity error\n");
1779 		} else {
1780 			pr_err("Decoded c0_cacheerr: %s cache fault in %s reference.\n",
1781 			       reg_val & (1<<30) ? "secondary" : "primary",
1782 			       reg_val & (1<<31) ? "data" : "insn");
1783 		}
1784 	} else {
1785 		pr_err("FTLB error exception\n");
1786 	}
1787 	/* Just print the cacheerr bits for now */
1788 	cache_parity_error();
1789 }
1790 
1791 /*
1792  * SDBBP EJTAG debug exception handler.
1793  * We skip the instruction and return to the next instruction.
1794  */
1795 void ejtag_exception_handler(struct pt_regs *regs)
1796 {
1797 	const int field = 2 * sizeof(unsigned long);
1798 	unsigned long depc, old_epc, old_ra;
1799 	unsigned int debug;
1800 
1801 	printk(KERN_DEBUG "SDBBP EJTAG debug exception - not handled yet, just ignored!\n");
1802 	depc = read_c0_depc();
1803 	debug = read_c0_debug();
1804 	printk(KERN_DEBUG "c0_depc = %0*lx, DEBUG = %08x\n", field, depc, debug);
1805 	if (debug & 0x80000000) {
1806 		/*
1807 		 * In branch delay slot.
1808 		 * We cheat a little bit here and use EPC to calculate the
1809 		 * debug return address (DEPC). EPC is restored after the
1810 		 * calculation.
1811 		 */
1812 		old_epc = regs->cp0_epc;
1813 		old_ra = regs->regs[31];
1814 		regs->cp0_epc = depc;
1815 		compute_return_epc(regs);
1816 		depc = regs->cp0_epc;
1817 		regs->cp0_epc = old_epc;
1818 		regs->regs[31] = old_ra;
1819 	} else
1820 		depc += 4;
1821 	write_c0_depc(depc);
1822 
1823 #if 0
1824 	printk(KERN_DEBUG "\n\n----- Enable EJTAG single stepping ----\n\n");
1825 	write_c0_debug(debug | 0x100);
1826 #endif
1827 }
1828 
1829 /*
1830  * NMI exception handler.
1831  * No lock; only written during early bootup by CPU 0.
1832  */
1833 static RAW_NOTIFIER_HEAD(nmi_chain);
1834 
1835 int register_nmi_notifier(struct notifier_block *nb)
1836 {
1837 	return raw_notifier_chain_register(&nmi_chain, nb);
1838 }
1839 
1840 void __noreturn nmi_exception_handler(struct pt_regs *regs)
1841 {
1842 	char str[100];
1843 
1844 	raw_notifier_call_chain(&nmi_chain, 0, regs);
1845 	bust_spinlocks(1);
1846 	snprintf(str, 100, "CPU%d NMI taken, CP0_EPC=%lx\n",
1847 		 smp_processor_id(), regs->cp0_epc);
1848 	regs->cp0_epc = read_c0_errorepc();
1849 	die(str, regs);
1850 }
1851 
1852 #define VECTORSPACING 0x100	/* for EI/VI mode */
1853 
1854 unsigned long ebase;
1855 unsigned long exception_handlers[32];
1856 unsigned long vi_handlers[64];
1857 
1858 void __init *set_except_vector(int n, void *addr)
1859 {
1860 	unsigned long handler = (unsigned long) addr;
1861 	unsigned long old_handler;
1862 
1863 #ifdef CONFIG_CPU_MICROMIPS
1864 	/*
1865 	 * Only the TLB handlers are cache aligned with an even
1866 	 * address. All other handlers are on an odd address and
1867 	 * require no modification. Otherwise, MIPS32 mode will
1868 	 * be entered when handling any TLB exceptions. That
1869 	 * would be bad...since we must stay in microMIPS mode.
1870 	 */
1871 	if (!(handler & 0x1))
1872 		handler |= 1;
1873 #endif
1874 	old_handler = xchg(&exception_handlers[n], handler);
1875 
1876 	if (n == 0 && cpu_has_divec) {
1877 #ifdef CONFIG_CPU_MICROMIPS
1878 		unsigned long jump_mask = ~((1 << 27) - 1);
1879 #else
1880 		unsigned long jump_mask = ~((1 << 28) - 1);
1881 #endif
1882 		u32 *buf = (u32 *)(ebase + 0x200);
1883 		unsigned int k0 = 26;
1884 		if ((handler & jump_mask) == ((ebase + 0x200) & jump_mask)) {
1885 			uasm_i_j(&buf, handler & ~jump_mask);
1886 			uasm_i_nop(&buf);
1887 		} else {
1888 			UASM_i_LA(&buf, k0, handler);
1889 			uasm_i_jr(&buf, k0);
1890 			uasm_i_nop(&buf);
1891 		}
1892 		local_flush_icache_range(ebase + 0x200, (unsigned long)buf);
1893 	}
1894 	return (void *)old_handler;
1895 }
1896 
1897 static void do_default_vi(void)
1898 {
1899 	show_regs(get_irq_regs());
1900 	panic("Caught unexpected vectored interrupt.");
1901 }
1902 
1903 static void *set_vi_srs_handler(int n, vi_handler_t addr, int srs)
1904 {
1905 	unsigned long handler;
1906 	unsigned long old_handler = vi_handlers[n];
1907 	int srssets = current_cpu_data.srsets;
1908 	u16 *h;
1909 	unsigned char *b;
1910 
1911 	BUG_ON(!cpu_has_veic && !cpu_has_vint);
1912 
1913 	if (addr == NULL) {
1914 		handler = (unsigned long) do_default_vi;
1915 		srs = 0;
1916 	} else
1917 		handler = (unsigned long) addr;
1918 	vi_handlers[n] = handler;
1919 
1920 	b = (unsigned char *)(ebase + 0x200 + n*VECTORSPACING);
1921 
1922 	if (srs >= srssets)
1923 		panic("Shadow register set %d not supported", srs);
1924 
1925 	if (cpu_has_veic) {
1926 		if (board_bind_eic_interrupt)
1927 			board_bind_eic_interrupt(n, srs);
1928 	} else if (cpu_has_vint) {
1929 		/* SRSMap is only defined if shadow sets are implemented */
1930 		if (srssets > 1)
1931 			change_c0_srsmap(0xf << n*4, srs << n*4);
1932 	}
1933 
1934 	if (srs == 0) {
1935 		/*
1936 		 * If no shadow set is selected then use the default handler
1937 		 * that does normal register saving and standard interrupt exit
1938 		 */
1939 		extern char except_vec_vi, except_vec_vi_lui;
1940 		extern char except_vec_vi_ori, except_vec_vi_end;
1941 		extern char rollback_except_vec_vi;
1942 		char *vec_start = using_rollback_handler() ?
1943 			&rollback_except_vec_vi : &except_vec_vi;
1944 #if defined(CONFIG_CPU_MICROMIPS) || defined(CONFIG_CPU_BIG_ENDIAN)
1945 		const int lui_offset = &except_vec_vi_lui - vec_start + 2;
1946 		const int ori_offset = &except_vec_vi_ori - vec_start + 2;
1947 #else
1948 		const int lui_offset = &except_vec_vi_lui - vec_start;
1949 		const int ori_offset = &except_vec_vi_ori - vec_start;
1950 #endif
1951 		const int handler_len = &except_vec_vi_end - vec_start;
1952 
1953 		if (handler_len > VECTORSPACING) {
1954 			/*
1955 			 * Sigh... panicing won't help as the console
1956 			 * is probably not configured :(
1957 			 */
1958 			panic("VECTORSPACING too small");
1959 		}
1960 
1961 		set_handler(((unsigned long)b - ebase), vec_start,
1962 #ifdef CONFIG_CPU_MICROMIPS
1963 				(handler_len - 1));
1964 #else
1965 				handler_len);
1966 #endif
1967 		h = (u16 *)(b + lui_offset);
1968 		*h = (handler >> 16) & 0xffff;
1969 		h = (u16 *)(b + ori_offset);
1970 		*h = (handler & 0xffff);
1971 		local_flush_icache_range((unsigned long)b,
1972 					 (unsigned long)(b+handler_len));
1973 	}
1974 	else {
1975 		/*
1976 		 * In other cases jump directly to the interrupt handler. It
1977 		 * is the handler's responsibility to save registers if required
1978 		 * (eg hi/lo) and return from the exception using "eret".
1979 		 */
1980 		u32 insn;
1981 
1982 		h = (u16 *)b;
1983 		/* j handler */
1984 #ifdef CONFIG_CPU_MICROMIPS
1985 		insn = 0xd4000000 | (((u32)handler & 0x07ffffff) >> 1);
1986 #else
1987 		insn = 0x08000000 | (((u32)handler & 0x0fffffff) >> 2);
1988 #endif
1989 		h[0] = (insn >> 16) & 0xffff;
1990 		h[1] = insn & 0xffff;
1991 		h[2] = 0;
1992 		h[3] = 0;
1993 		local_flush_icache_range((unsigned long)b,
1994 					 (unsigned long)(b+8));
1995 	}
1996 
1997 	return (void *)old_handler;
1998 }
1999 
2000 void *set_vi_handler(int n, vi_handler_t addr)
2001 {
2002 	return set_vi_srs_handler(n, addr, 0);
2003 }
2004 
2005 extern void tlb_init(void);
2006 
2007 /*
2008  * Timer interrupt
2009  */
2010 int cp0_compare_irq;
2011 EXPORT_SYMBOL_GPL(cp0_compare_irq);
2012 int cp0_compare_irq_shift;
2013 
2014 /*
2015  * Performance counter IRQ or -1 if shared with timer
2016  */
2017 int cp0_perfcount_irq;
2018 EXPORT_SYMBOL_GPL(cp0_perfcount_irq);
2019 
2020 /*
2021  * Fast debug channel IRQ or -1 if not present
2022  */
2023 int cp0_fdc_irq;
2024 EXPORT_SYMBOL_GPL(cp0_fdc_irq);
2025 
2026 static int noulri;
2027 
2028 static int __init ulri_disable(char *s)
2029 {
2030 	pr_info("Disabling ulri\n");
2031 	noulri = 1;
2032 
2033 	return 1;
2034 }
2035 __setup("noulri", ulri_disable);
2036 
2037 /* configure STATUS register */
2038 static void configure_status(void)
2039 {
2040 	/*
2041 	 * Disable coprocessors and select 32-bit or 64-bit addressing
2042 	 * and the 16/32 or 32/32 FPR register model.  Reset the BEV
2043 	 * flag that some firmware may have left set and the TS bit (for
2044 	 * IP27).  Set XX for ISA IV code to work.
2045 	 */
2046 	unsigned int status_set = ST0_CU0;
2047 #ifdef CONFIG_64BIT
2048 	status_set |= ST0_FR|ST0_KX|ST0_SX|ST0_UX;
2049 #endif
2050 	if (current_cpu_data.isa_level & MIPS_CPU_ISA_IV)
2051 		status_set |= ST0_XX;
2052 	if (cpu_has_dsp)
2053 		status_set |= ST0_MX;
2054 
2055 	change_c0_status(ST0_CU|ST0_MX|ST0_RE|ST0_FR|ST0_BEV|ST0_TS|ST0_KX|ST0_SX|ST0_UX,
2056 			 status_set);
2057 }
2058 
2059 /* configure HWRENA register */
2060 static void configure_hwrena(void)
2061 {
2062 	unsigned int hwrena = cpu_hwrena_impl_bits;
2063 
2064 	if (cpu_has_mips_r2_r6)
2065 		hwrena |= 0x0000000f;
2066 
2067 	if (!noulri && cpu_has_userlocal)
2068 		hwrena |= (1 << 29);
2069 
2070 	if (hwrena)
2071 		write_c0_hwrena(hwrena);
2072 }
2073 
2074 static void configure_exception_vector(void)
2075 {
2076 	if (cpu_has_veic || cpu_has_vint) {
2077 		unsigned long sr = set_c0_status(ST0_BEV);
2078 		write_c0_ebase(ebase);
2079 		write_c0_status(sr);
2080 		/* Setting vector spacing enables EI/VI mode  */
2081 		change_c0_intctl(0x3e0, VECTORSPACING);
2082 	}
2083 	if (cpu_has_divec) {
2084 		if (cpu_has_mipsmt) {
2085 			unsigned int vpflags = dvpe();
2086 			set_c0_cause(CAUSEF_IV);
2087 			evpe(vpflags);
2088 		} else
2089 			set_c0_cause(CAUSEF_IV);
2090 	}
2091 }
2092 
2093 void per_cpu_trap_init(bool is_boot_cpu)
2094 {
2095 	unsigned int cpu = smp_processor_id();
2096 
2097 	configure_status();
2098 	configure_hwrena();
2099 
2100 	configure_exception_vector();
2101 
2102 	/*
2103 	 * Before R2 both interrupt numbers were fixed to 7, so on R2 only:
2104 	 *
2105 	 *  o read IntCtl.IPTI to determine the timer interrupt
2106 	 *  o read IntCtl.IPPCI to determine the performance counter interrupt
2107 	 *  o read IntCtl.IPFDC to determine the fast debug channel interrupt
2108 	 */
2109 	if (cpu_has_mips_r2_r6) {
2110 		cp0_compare_irq_shift = CAUSEB_TI - CAUSEB_IP;
2111 		cp0_compare_irq = (read_c0_intctl() >> INTCTLB_IPTI) & 7;
2112 		cp0_perfcount_irq = (read_c0_intctl() >> INTCTLB_IPPCI) & 7;
2113 		cp0_fdc_irq = (read_c0_intctl() >> INTCTLB_IPFDC) & 7;
2114 		if (!cp0_fdc_irq)
2115 			cp0_fdc_irq = -1;
2116 
2117 	} else {
2118 		cp0_compare_irq = CP0_LEGACY_COMPARE_IRQ;
2119 		cp0_compare_irq_shift = CP0_LEGACY_PERFCNT_IRQ;
2120 		cp0_perfcount_irq = -1;
2121 		cp0_fdc_irq = -1;
2122 	}
2123 
2124 	if (!cpu_data[cpu].asid_cache)
2125 		cpu_data[cpu].asid_cache = ASID_FIRST_VERSION;
2126 
2127 	atomic_inc(&init_mm.mm_count);
2128 	current->active_mm = &init_mm;
2129 	BUG_ON(current->mm);
2130 	enter_lazy_tlb(&init_mm, current);
2131 
2132 		/* Boot CPU's cache setup in setup_arch(). */
2133 		if (!is_boot_cpu)
2134 			cpu_cache_init();
2135 		tlb_init();
2136 	TLBMISS_HANDLER_SETUP();
2137 }
2138 
2139 /* Install CPU exception handler */
2140 void set_handler(unsigned long offset, void *addr, unsigned long size)
2141 {
2142 #ifdef CONFIG_CPU_MICROMIPS
2143 	memcpy((void *)(ebase + offset), ((unsigned char *)addr - 1), size);
2144 #else
2145 	memcpy((void *)(ebase + offset), addr, size);
2146 #endif
2147 	local_flush_icache_range(ebase + offset, ebase + offset + size);
2148 }
2149 
2150 static char panic_null_cerr[] =
2151 	"Trying to set NULL cache error exception handler";
2152 
2153 /*
2154  * Install uncached CPU exception handler.
2155  * This is suitable only for the cache error exception which is the only
2156  * exception handler that is being run uncached.
2157  */
2158 void set_uncached_handler(unsigned long offset, void *addr,
2159 	unsigned long size)
2160 {
2161 	unsigned long uncached_ebase = CKSEG1ADDR(ebase);
2162 
2163 	if (!addr)
2164 		panic(panic_null_cerr);
2165 
2166 	memcpy((void *)(uncached_ebase + offset), addr, size);
2167 }
2168 
2169 static int __initdata rdhwr_noopt;
2170 static int __init set_rdhwr_noopt(char *str)
2171 {
2172 	rdhwr_noopt = 1;
2173 	return 1;
2174 }
2175 
2176 __setup("rdhwr_noopt", set_rdhwr_noopt);
2177 
2178 void __init trap_init(void)
2179 {
2180 	extern char except_vec3_generic;
2181 	extern char except_vec4;
2182 	extern char except_vec3_r4000;
2183 	unsigned long i;
2184 
2185 	check_wait();
2186 
2187 #if defined(CONFIG_KGDB)
2188 	if (kgdb_early_setup)
2189 		return; /* Already done */
2190 #endif
2191 
2192 	if (cpu_has_veic || cpu_has_vint) {
2193 		unsigned long size = 0x200 + VECTORSPACING*64;
2194 		ebase = (unsigned long)
2195 			__alloc_bootmem(size, 1 << fls(size), 0);
2196 	} else {
2197 #ifdef CONFIG_KVM_GUEST
2198 #define KVM_GUEST_KSEG0     0x40000000
2199         ebase = KVM_GUEST_KSEG0;
2200 #else
2201         ebase = CKSEG0;
2202 #endif
2203 		if (cpu_has_mips_r2_r6)
2204 			ebase += (read_c0_ebase() & 0x3ffff000);
2205 	}
2206 
2207 	if (cpu_has_mmips) {
2208 		unsigned int config3 = read_c0_config3();
2209 
2210 		if (IS_ENABLED(CONFIG_CPU_MICROMIPS))
2211 			write_c0_config3(config3 | MIPS_CONF3_ISA_OE);
2212 		else
2213 			write_c0_config3(config3 & ~MIPS_CONF3_ISA_OE);
2214 	}
2215 
2216 	if (board_ebase_setup)
2217 		board_ebase_setup();
2218 	per_cpu_trap_init(true);
2219 
2220 	/*
2221 	 * Copy the generic exception handlers to their final destination.
2222 	 * This will be overriden later as suitable for a particular
2223 	 * configuration.
2224 	 */
2225 	set_handler(0x180, &except_vec3_generic, 0x80);
2226 
2227 	/*
2228 	 * Setup default vectors
2229 	 */
2230 	for (i = 0; i <= 31; i++)
2231 		set_except_vector(i, handle_reserved);
2232 
2233 	/*
2234 	 * Copy the EJTAG debug exception vector handler code to it's final
2235 	 * destination.
2236 	 */
2237 	if (cpu_has_ejtag && board_ejtag_handler_setup)
2238 		board_ejtag_handler_setup();
2239 
2240 	/*
2241 	 * Only some CPUs have the watch exceptions.
2242 	 */
2243 	if (cpu_has_watch)
2244 		set_except_vector(23, handle_watch);
2245 
2246 	/*
2247 	 * Initialise interrupt handlers
2248 	 */
2249 	if (cpu_has_veic || cpu_has_vint) {
2250 		int nvec = cpu_has_veic ? 64 : 8;
2251 		for (i = 0; i < nvec; i++)
2252 			set_vi_handler(i, NULL);
2253 	}
2254 	else if (cpu_has_divec)
2255 		set_handler(0x200, &except_vec4, 0x8);
2256 
2257 	/*
2258 	 * Some CPUs can enable/disable for cache parity detection, but does
2259 	 * it different ways.
2260 	 */
2261 	parity_protection_init();
2262 
2263 	/*
2264 	 * The Data Bus Errors / Instruction Bus Errors are signaled
2265 	 * by external hardware.  Therefore these two exceptions
2266 	 * may have board specific handlers.
2267 	 */
2268 	if (board_be_init)
2269 		board_be_init();
2270 
2271 	set_except_vector(0, using_rollback_handler() ? rollback_handle_int
2272 						      : handle_int);
2273 	set_except_vector(1, handle_tlbm);
2274 	set_except_vector(2, handle_tlbl);
2275 	set_except_vector(3, handle_tlbs);
2276 
2277 	set_except_vector(4, handle_adel);
2278 	set_except_vector(5, handle_ades);
2279 
2280 	set_except_vector(6, handle_ibe);
2281 	set_except_vector(7, handle_dbe);
2282 
2283 	set_except_vector(8, handle_sys);
2284 	set_except_vector(9, handle_bp);
2285 	set_except_vector(10, rdhwr_noopt ? handle_ri :
2286 			  (cpu_has_vtag_icache ?
2287 			   handle_ri_rdhwr_vivt : handle_ri_rdhwr));
2288 	set_except_vector(11, handle_cpu);
2289 	set_except_vector(12, handle_ov);
2290 	set_except_vector(13, handle_tr);
2291 	set_except_vector(14, handle_msa_fpe);
2292 
2293 	if (current_cpu_type() == CPU_R6000 ||
2294 	    current_cpu_type() == CPU_R6000A) {
2295 		/*
2296 		 * The R6000 is the only R-series CPU that features a machine
2297 		 * check exception (similar to the R4000 cache error) and
2298 		 * unaligned ldc1/sdc1 exception.  The handlers have not been
2299 		 * written yet.	 Well, anyway there is no R6000 machine on the
2300 		 * current list of targets for Linux/MIPS.
2301 		 * (Duh, crap, there is someone with a triple R6k machine)
2302 		 */
2303 		//set_except_vector(14, handle_mc);
2304 		//set_except_vector(15, handle_ndc);
2305 	}
2306 
2307 
2308 	if (board_nmi_handler_setup)
2309 		board_nmi_handler_setup();
2310 
2311 	if (cpu_has_fpu && !cpu_has_nofpuex)
2312 		set_except_vector(15, handle_fpe);
2313 
2314 	set_except_vector(16, handle_ftlb);
2315 
2316 	if (cpu_has_rixiex) {
2317 		set_except_vector(19, tlb_do_page_fault_0);
2318 		set_except_vector(20, tlb_do_page_fault_0);
2319 	}
2320 
2321 	set_except_vector(21, handle_msa);
2322 	set_except_vector(22, handle_mdmx);
2323 
2324 	if (cpu_has_mcheck)
2325 		set_except_vector(24, handle_mcheck);
2326 
2327 	if (cpu_has_mipsmt)
2328 		set_except_vector(25, handle_mt);
2329 
2330 	set_except_vector(26, handle_dsp);
2331 
2332 	if (board_cache_error_setup)
2333 		board_cache_error_setup();
2334 
2335 	if (cpu_has_vce)
2336 		/* Special exception: R4[04]00 uses also the divec space. */
2337 		set_handler(0x180, &except_vec3_r4000, 0x100);
2338 	else if (cpu_has_4kex)
2339 		set_handler(0x180, &except_vec3_generic, 0x80);
2340 	else
2341 		set_handler(0x080, &except_vec3_generic, 0x80);
2342 
2343 	local_flush_icache_range(ebase, ebase + 0x400);
2344 
2345 	sort_extable(__start___dbe_table, __stop___dbe_table);
2346 
2347 	cu2_notifier(default_cu2_call, 0x80000000);	/* Run last  */
2348 }
2349 
2350 static int trap_pm_notifier(struct notifier_block *self, unsigned long cmd,
2351 			    void *v)
2352 {
2353 	switch (cmd) {
2354 	case CPU_PM_ENTER_FAILED:
2355 	case CPU_PM_EXIT:
2356 		configure_status();
2357 		configure_hwrena();
2358 		configure_exception_vector();
2359 
2360 		/* Restore register with CPU number for TLB handlers */
2361 		TLBMISS_HANDLER_RESTORE();
2362 
2363 		break;
2364 	}
2365 
2366 	return NOTIFY_OK;
2367 }
2368 
2369 static struct notifier_block trap_pm_notifier_block = {
2370 	.notifier_call = trap_pm_notifier,
2371 };
2372 
2373 static int __init trap_pm_init(void)
2374 {
2375 	return cpu_pm_register_notifier(&trap_pm_notifier_block);
2376 }
2377 arch_initcall(trap_pm_init);
2378