xref: /linux/arch/mips/kernel/traps.c (revision 606d099cdd1080bbb50ea50dc52d98252f8f10a1)
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) 2000, 01 MIPS Technologies, Inc.
12  * Copyright (C) 2002, 2003, 2004, 2005  Maciej W. Rozycki
13  */
14 #include <linux/init.h>
15 #include <linux/mm.h>
16 #include <linux/module.h>
17 #include <linux/sched.h>
18 #include <linux/smp.h>
19 #include <linux/smp_lock.h>
20 #include <linux/spinlock.h>
21 #include <linux/kallsyms.h>
22 #include <linux/bootmem.h>
23 #include <linux/interrupt.h>
24 
25 #include <asm/bootinfo.h>
26 #include <asm/branch.h>
27 #include <asm/break.h>
28 #include <asm/cpu.h>
29 #include <asm/dsp.h>
30 #include <asm/fpu.h>
31 #include <asm/mipsregs.h>
32 #include <asm/mipsmtregs.h>
33 #include <asm/module.h>
34 #include <asm/pgtable.h>
35 #include <asm/ptrace.h>
36 #include <asm/sections.h>
37 #include <asm/system.h>
38 #include <asm/tlbdebug.h>
39 #include <asm/traps.h>
40 #include <asm/uaccess.h>
41 #include <asm/mmu_context.h>
42 #include <asm/watch.h>
43 #include <asm/types.h>
44 #include <asm/stacktrace.h>
45 
46 extern asmlinkage void handle_int(void);
47 extern asmlinkage void handle_tlbm(void);
48 extern asmlinkage void handle_tlbl(void);
49 extern asmlinkage void handle_tlbs(void);
50 extern asmlinkage void handle_adel(void);
51 extern asmlinkage void handle_ades(void);
52 extern asmlinkage void handle_ibe(void);
53 extern asmlinkage void handle_dbe(void);
54 extern asmlinkage void handle_sys(void);
55 extern asmlinkage void handle_bp(void);
56 extern asmlinkage void handle_ri(void);
57 extern asmlinkage void handle_ri_rdhwr_vivt(void);
58 extern asmlinkage void handle_ri_rdhwr(void);
59 extern asmlinkage void handle_cpu(void);
60 extern asmlinkage void handle_ov(void);
61 extern asmlinkage void handle_tr(void);
62 extern asmlinkage void handle_fpe(void);
63 extern asmlinkage void handle_mdmx(void);
64 extern asmlinkage void handle_watch(void);
65 extern asmlinkage void handle_mt(void);
66 extern asmlinkage void handle_dsp(void);
67 extern asmlinkage void handle_mcheck(void);
68 extern asmlinkage void handle_reserved(void);
69 
70 extern int fpu_emulator_cop1Handler(struct pt_regs *xcp,
71 	struct mips_fpu_struct *ctx, int has_fpu);
72 
73 void (*board_be_init)(void);
74 int (*board_be_handler)(struct pt_regs *regs, int is_fixup);
75 void (*board_nmi_handler_setup)(void);
76 void (*board_ejtag_handler_setup)(void);
77 void (*board_bind_eic_interrupt)(int irq, int regset);
78 
79 
80 static void show_raw_backtrace(unsigned long reg29)
81 {
82 	unsigned long *sp = (unsigned long *)reg29;
83 	unsigned long addr;
84 
85 	printk("Call Trace:");
86 #ifdef CONFIG_KALLSYMS
87 	printk("\n");
88 #endif
89 	while (!kstack_end(sp)) {
90 		addr = *sp++;
91 		if (__kernel_text_address(addr))
92 			print_ip_sym(addr);
93 	}
94 	printk("\n");
95 }
96 
97 #ifdef CONFIG_KALLSYMS
98 int raw_show_trace;
99 static int __init set_raw_show_trace(char *str)
100 {
101 	raw_show_trace = 1;
102 	return 1;
103 }
104 __setup("raw_show_trace", set_raw_show_trace);
105 #endif
106 
107 static void show_backtrace(struct task_struct *task, struct pt_regs *regs)
108 {
109 	unsigned long sp = regs->regs[29];
110 	unsigned long ra = regs->regs[31];
111 	unsigned long pc = regs->cp0_epc;
112 
113 	if (raw_show_trace || !__kernel_text_address(pc)) {
114 		show_raw_backtrace(sp);
115 		return;
116 	}
117 	printk("Call Trace:\n");
118 	do {
119 		print_ip_sym(pc);
120 		pc = unwind_stack(task, &sp, pc, &ra);
121 	} while (pc);
122 	printk("\n");
123 }
124 
125 /*
126  * This routine abuses get_user()/put_user() to reference pointers
127  * with at least a bit of error checking ...
128  */
129 static void show_stacktrace(struct task_struct *task, struct pt_regs *regs)
130 {
131 	const int field = 2 * sizeof(unsigned long);
132 	long stackdata;
133 	int i;
134 	unsigned long *sp = (unsigned long *)regs->regs[29];
135 
136 	printk("Stack :");
137 	i = 0;
138 	while ((unsigned long) sp & (PAGE_SIZE - 1)) {
139 		if (i && ((i % (64 / field)) == 0))
140 			printk("\n       ");
141 		if (i > 39) {
142 			printk(" ...");
143 			break;
144 		}
145 
146 		if (__get_user(stackdata, sp++)) {
147 			printk(" (Bad stack address)");
148 			break;
149 		}
150 
151 		printk(" %0*lx", field, stackdata);
152 		i++;
153 	}
154 	printk("\n");
155 	show_backtrace(task, regs);
156 }
157 
158 void show_stack(struct task_struct *task, unsigned long *sp)
159 {
160 	struct pt_regs regs;
161 	if (sp) {
162 		regs.regs[29] = (unsigned long)sp;
163 		regs.regs[31] = 0;
164 		regs.cp0_epc = 0;
165 	} else {
166 		if (task && task != current) {
167 			regs.regs[29] = task->thread.reg29;
168 			regs.regs[31] = 0;
169 			regs.cp0_epc = task->thread.reg31;
170 		} else {
171 			prepare_frametrace(&regs);
172 		}
173 	}
174 	show_stacktrace(task, &regs);
175 }
176 
177 /*
178  * The architecture-independent dump_stack generator
179  */
180 void dump_stack(void)
181 {
182 	struct pt_regs regs;
183 
184 	prepare_frametrace(&regs);
185 	show_backtrace(current, &regs);
186 }
187 
188 EXPORT_SYMBOL(dump_stack);
189 
190 void show_code(unsigned int *pc)
191 {
192 	long i;
193 
194 	printk("\nCode:");
195 
196 	for(i = -3 ; i < 6 ; i++) {
197 		unsigned int insn;
198 		if (__get_user(insn, pc + i)) {
199 			printk(" (Bad address in epc)\n");
200 			break;
201 		}
202 		printk("%c%08x%c", (i?' ':'<'), insn, (i?' ':'>'));
203 	}
204 }
205 
206 void show_regs(struct pt_regs *regs)
207 {
208 	const int field = 2 * sizeof(unsigned long);
209 	unsigned int cause = regs->cp0_cause;
210 	int i;
211 
212 	printk("Cpu %d\n", smp_processor_id());
213 
214 	/*
215 	 * Saved main processor registers
216 	 */
217 	for (i = 0; i < 32; ) {
218 		if ((i % 4) == 0)
219 			printk("$%2d   :", i);
220 		if (i == 0)
221 			printk(" %0*lx", field, 0UL);
222 		else if (i == 26 || i == 27)
223 			printk(" %*s", field, "");
224 		else
225 			printk(" %0*lx", field, regs->regs[i]);
226 
227 		i++;
228 		if ((i % 4) == 0)
229 			printk("\n");
230 	}
231 
232 	printk("Hi    : %0*lx\n", field, regs->hi);
233 	printk("Lo    : %0*lx\n", field, regs->lo);
234 
235 	/*
236 	 * Saved cp0 registers
237 	 */
238 	printk("epc   : %0*lx ", field, regs->cp0_epc);
239 	print_symbol("%s ", regs->cp0_epc);
240 	printk("    %s\n", print_tainted());
241 	printk("ra    : %0*lx ", field, regs->regs[31]);
242 	print_symbol("%s\n", regs->regs[31]);
243 
244 	printk("Status: %08x    ", (uint32_t) regs->cp0_status);
245 
246 	if (current_cpu_data.isa_level == MIPS_CPU_ISA_I) {
247 		if (regs->cp0_status & ST0_KUO)
248 			printk("KUo ");
249 		if (regs->cp0_status & ST0_IEO)
250 			printk("IEo ");
251 		if (regs->cp0_status & ST0_KUP)
252 			printk("KUp ");
253 		if (regs->cp0_status & ST0_IEP)
254 			printk("IEp ");
255 		if (regs->cp0_status & ST0_KUC)
256 			printk("KUc ");
257 		if (regs->cp0_status & ST0_IEC)
258 			printk("IEc ");
259 	} else {
260 		if (regs->cp0_status & ST0_KX)
261 			printk("KX ");
262 		if (regs->cp0_status & ST0_SX)
263 			printk("SX ");
264 		if (regs->cp0_status & ST0_UX)
265 			printk("UX ");
266 		switch (regs->cp0_status & ST0_KSU) {
267 		case KSU_USER:
268 			printk("USER ");
269 			break;
270 		case KSU_SUPERVISOR:
271 			printk("SUPERVISOR ");
272 			break;
273 		case KSU_KERNEL:
274 			printk("KERNEL ");
275 			break;
276 		default:
277 			printk("BAD_MODE ");
278 			break;
279 		}
280 		if (regs->cp0_status & ST0_ERL)
281 			printk("ERL ");
282 		if (regs->cp0_status & ST0_EXL)
283 			printk("EXL ");
284 		if (regs->cp0_status & ST0_IE)
285 			printk("IE ");
286 	}
287 	printk("\n");
288 
289 	printk("Cause : %08x\n", cause);
290 
291 	cause = (cause & CAUSEF_EXCCODE) >> CAUSEB_EXCCODE;
292 	if (1 <= cause && cause <= 5)
293 		printk("BadVA : %0*lx\n", field, regs->cp0_badvaddr);
294 
295 	printk("PrId  : %08x\n", read_c0_prid());
296 }
297 
298 void show_registers(struct pt_regs *regs)
299 {
300 	show_regs(regs);
301 	print_modules();
302 	printk("Process %s (pid: %d, threadinfo=%p, task=%p)\n",
303 	        current->comm, current->pid, current_thread_info(), current);
304 	show_stacktrace(current, regs);
305 	show_code((unsigned int *) regs->cp0_epc);
306 	printk("\n");
307 }
308 
309 static DEFINE_SPINLOCK(die_lock);
310 
311 NORET_TYPE void ATTRIB_NORET die(const char * str, struct pt_regs * regs)
312 {
313 	static int die_counter;
314 #ifdef CONFIG_MIPS_MT_SMTC
315 	unsigned long dvpret = dvpe();
316 #endif /* CONFIG_MIPS_MT_SMTC */
317 
318 	console_verbose();
319 	spin_lock_irq(&die_lock);
320 	bust_spinlocks(1);
321 #ifdef CONFIG_MIPS_MT_SMTC
322 	mips_mt_regdump(dvpret);
323 #endif /* CONFIG_MIPS_MT_SMTC */
324 	printk("%s[#%d]:\n", str, ++die_counter);
325 	show_registers(regs);
326 	spin_unlock_irq(&die_lock);
327 
328 	if (in_interrupt())
329 		panic("Fatal exception in interrupt");
330 
331 	if (panic_on_oops) {
332 		printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
333 		ssleep(5);
334 		panic("Fatal exception");
335 	}
336 
337 	do_exit(SIGSEGV);
338 }
339 
340 extern const struct exception_table_entry __start___dbe_table[];
341 extern const struct exception_table_entry __stop___dbe_table[];
342 
343 void __declare_dbe_table(void)
344 {
345 	__asm__ __volatile__(
346 	".section\t__dbe_table,\"a\"\n\t"
347 	".previous"
348 	);
349 }
350 
351 /* Given an address, look for it in the exception tables. */
352 static const struct exception_table_entry *search_dbe_tables(unsigned long addr)
353 {
354 	const struct exception_table_entry *e;
355 
356 	e = search_extable(__start___dbe_table, __stop___dbe_table - 1, addr);
357 	if (!e)
358 		e = search_module_dbetables(addr);
359 	return e;
360 }
361 
362 asmlinkage void do_be(struct pt_regs *regs)
363 {
364 	const int field = 2 * sizeof(unsigned long);
365 	const struct exception_table_entry *fixup = NULL;
366 	int data = regs->cp0_cause & 4;
367 	int action = MIPS_BE_FATAL;
368 
369 	/* XXX For now.  Fixme, this searches the wrong table ...  */
370 	if (data && !user_mode(regs))
371 		fixup = search_dbe_tables(exception_epc(regs));
372 
373 	if (fixup)
374 		action = MIPS_BE_FIXUP;
375 
376 	if (board_be_handler)
377 		action = board_be_handler(regs, fixup != 0);
378 
379 	switch (action) {
380 	case MIPS_BE_DISCARD:
381 		return;
382 	case MIPS_BE_FIXUP:
383 		if (fixup) {
384 			regs->cp0_epc = fixup->nextinsn;
385 			return;
386 		}
387 		break;
388 	default:
389 		break;
390 	}
391 
392 	/*
393 	 * Assume it would be too dangerous to continue ...
394 	 */
395 	printk(KERN_ALERT "%s bus error, epc == %0*lx, ra == %0*lx\n",
396 	       data ? "Data" : "Instruction",
397 	       field, regs->cp0_epc, field, regs->regs[31]);
398 	die_if_kernel("Oops", regs);
399 	force_sig(SIGBUS, current);
400 }
401 
402 /*
403  * ll/sc emulation
404  */
405 
406 #define OPCODE 0xfc000000
407 #define BASE   0x03e00000
408 #define RT     0x001f0000
409 #define OFFSET 0x0000ffff
410 #define LL     0xc0000000
411 #define SC     0xe0000000
412 #define SPEC3  0x7c000000
413 #define RD     0x0000f800
414 #define FUNC   0x0000003f
415 #define RDHWR  0x0000003b
416 
417 /*
418  * The ll_bit is cleared by r*_switch.S
419  */
420 
421 unsigned long ll_bit;
422 
423 static struct task_struct *ll_task = NULL;
424 
425 static inline void simulate_ll(struct pt_regs *regs, unsigned int opcode)
426 {
427 	unsigned long value, __user *vaddr;
428 	long offset;
429 	int signal = 0;
430 
431 	/*
432 	 * analyse the ll instruction that just caused a ri exception
433 	 * and put the referenced address to addr.
434 	 */
435 
436 	/* sign extend offset */
437 	offset = opcode & OFFSET;
438 	offset <<= 16;
439 	offset >>= 16;
440 
441 	vaddr = (unsigned long __user *)
442 	        ((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
443 
444 	if ((unsigned long)vaddr & 3) {
445 		signal = SIGBUS;
446 		goto sig;
447 	}
448 	if (get_user(value, vaddr)) {
449 		signal = SIGSEGV;
450 		goto sig;
451 	}
452 
453 	preempt_disable();
454 
455 	if (ll_task == NULL || ll_task == current) {
456 		ll_bit = 1;
457 	} else {
458 		ll_bit = 0;
459 	}
460 	ll_task = current;
461 
462 	preempt_enable();
463 
464 	compute_return_epc(regs);
465 
466 	regs->regs[(opcode & RT) >> 16] = value;
467 
468 	return;
469 
470 sig:
471 	force_sig(signal, current);
472 }
473 
474 static inline void simulate_sc(struct pt_regs *regs, unsigned int opcode)
475 {
476 	unsigned long __user *vaddr;
477 	unsigned long reg;
478 	long offset;
479 	int signal = 0;
480 
481 	/*
482 	 * analyse the sc instruction that just caused a ri exception
483 	 * and put the referenced address to addr.
484 	 */
485 
486 	/* sign extend offset */
487 	offset = opcode & OFFSET;
488 	offset <<= 16;
489 	offset >>= 16;
490 
491 	vaddr = (unsigned long __user *)
492 	        ((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
493 	reg = (opcode & RT) >> 16;
494 
495 	if ((unsigned long)vaddr & 3) {
496 		signal = SIGBUS;
497 		goto sig;
498 	}
499 
500 	preempt_disable();
501 
502 	if (ll_bit == 0 || ll_task != current) {
503 		compute_return_epc(regs);
504 		regs->regs[reg] = 0;
505 		preempt_enable();
506 		return;
507 	}
508 
509 	preempt_enable();
510 
511 	if (put_user(regs->regs[reg], vaddr)) {
512 		signal = SIGSEGV;
513 		goto sig;
514 	}
515 
516 	compute_return_epc(regs);
517 	regs->regs[reg] = 1;
518 
519 	return;
520 
521 sig:
522 	force_sig(signal, current);
523 }
524 
525 /*
526  * ll uses the opcode of lwc0 and sc uses the opcode of swc0.  That is both
527  * opcodes are supposed to result in coprocessor unusable exceptions if
528  * executed on ll/sc-less processors.  That's the theory.  In practice a
529  * few processors such as NEC's VR4100 throw reserved instruction exceptions
530  * instead, so we're doing the emulation thing in both exception handlers.
531  */
532 static inline int simulate_llsc(struct pt_regs *regs)
533 {
534 	unsigned int opcode;
535 
536 	if (get_user(opcode, (unsigned int __user *) exception_epc(regs)))
537 		goto out_sigsegv;
538 
539 	if ((opcode & OPCODE) == LL) {
540 		simulate_ll(regs, opcode);
541 		return 0;
542 	}
543 	if ((opcode & OPCODE) == SC) {
544 		simulate_sc(regs, opcode);
545 		return 0;
546 	}
547 
548 	return -EFAULT;			/* Strange things going on ... */
549 
550 out_sigsegv:
551 	force_sig(SIGSEGV, current);
552 	return -EFAULT;
553 }
554 
555 /*
556  * Simulate trapping 'rdhwr' instructions to provide user accessible
557  * registers not implemented in hardware.  The only current use of this
558  * is the thread area pointer.
559  */
560 static inline int simulate_rdhwr(struct pt_regs *regs)
561 {
562 	struct thread_info *ti = task_thread_info(current);
563 	unsigned int opcode;
564 
565 	if (get_user(opcode, (unsigned int __user *) exception_epc(regs)))
566 		goto out_sigsegv;
567 
568 	if (unlikely(compute_return_epc(regs)))
569 		return -EFAULT;
570 
571 	if ((opcode & OPCODE) == SPEC3 && (opcode & FUNC) == RDHWR) {
572 		int rd = (opcode & RD) >> 11;
573 		int rt = (opcode & RT) >> 16;
574 		switch (rd) {
575 			case 29:
576 				regs->regs[rt] = ti->tp_value;
577 				return 0;
578 			default:
579 				return -EFAULT;
580 		}
581 	}
582 
583 	/* Not ours.  */
584 	return -EFAULT;
585 
586 out_sigsegv:
587 	force_sig(SIGSEGV, current);
588 	return -EFAULT;
589 }
590 
591 asmlinkage void do_ov(struct pt_regs *regs)
592 {
593 	siginfo_t info;
594 
595 	die_if_kernel("Integer overflow", regs);
596 
597 	info.si_code = FPE_INTOVF;
598 	info.si_signo = SIGFPE;
599 	info.si_errno = 0;
600 	info.si_addr = (void __user *) regs->cp0_epc;
601 	force_sig_info(SIGFPE, &info, current);
602 }
603 
604 /*
605  * XXX Delayed fp exceptions when doing a lazy ctx switch XXX
606  */
607 asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
608 {
609 	die_if_kernel("FP exception in kernel code", regs);
610 
611 	if (fcr31 & FPU_CSR_UNI_X) {
612 		int sig;
613 
614 		preempt_disable();
615 
616 #ifdef CONFIG_PREEMPT
617 		if (!is_fpu_owner()) {
618 			/* We might lose fpu before disabling preempt... */
619 			own_fpu();
620 			BUG_ON(!used_math());
621 			restore_fp(current);
622 		}
623 #endif
624 		/*
625 		 * Unimplemented operation exception.  If we've got the full
626 		 * software emulator on-board, let's use it...
627 		 *
628 		 * Force FPU to dump state into task/thread context.  We're
629 		 * moving a lot of data here for what is probably a single
630 		 * instruction, but the alternative is to pre-decode the FP
631 		 * register operands before invoking the emulator, which seems
632 		 * a bit extreme for what should be an infrequent event.
633 		 */
634 		save_fp(current);
635 		/* Ensure 'resume' not overwrite saved fp context again. */
636 		lose_fpu();
637 
638 		preempt_enable();
639 
640 		/* Run the emulator */
641 		sig = fpu_emulator_cop1Handler (regs, &current->thread.fpu, 1);
642 
643 		preempt_disable();
644 
645 		own_fpu();	/* Using the FPU again.  */
646 		/*
647 		 * We can't allow the emulated instruction to leave any of
648 		 * the cause bit set in $fcr31.
649 		 */
650 		current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
651 
652 		/* Restore the hardware register state */
653 		restore_fp(current);
654 
655 		preempt_enable();
656 
657 		/* If something went wrong, signal */
658 		if (sig)
659 			force_sig(sig, current);
660 
661 		return;
662 	}
663 
664 	force_sig(SIGFPE, current);
665 }
666 
667 asmlinkage void do_bp(struct pt_regs *regs)
668 {
669 	unsigned int opcode, bcode;
670 	siginfo_t info;
671 
672 	if (get_user(opcode, (unsigned int __user *) exception_epc(regs)))
673 		goto out_sigsegv;
674 
675 	/*
676 	 * There is the ancient bug in the MIPS assemblers that the break
677 	 * code starts left to bit 16 instead to bit 6 in the opcode.
678 	 * Gas is bug-compatible, but not always, grrr...
679 	 * We handle both cases with a simple heuristics.  --macro
680 	 */
681 	bcode = ((opcode >> 6) & ((1 << 20) - 1));
682 	if (bcode < (1 << 10))
683 		bcode <<= 10;
684 
685 	/*
686 	 * (A short test says that IRIX 5.3 sends SIGTRAP for all break
687 	 * insns, even for break codes that indicate arithmetic failures.
688 	 * Weird ...)
689 	 * But should we continue the brokenness???  --macro
690 	 */
691 	switch (bcode) {
692 	case BRK_OVERFLOW << 10:
693 	case BRK_DIVZERO << 10:
694 		die_if_kernel("Break instruction in kernel code", regs);
695 		if (bcode == (BRK_DIVZERO << 10))
696 			info.si_code = FPE_INTDIV;
697 		else
698 			info.si_code = FPE_INTOVF;
699 		info.si_signo = SIGFPE;
700 		info.si_errno = 0;
701 		info.si_addr = (void __user *) regs->cp0_epc;
702 		force_sig_info(SIGFPE, &info, current);
703 		break;
704 	case BRK_BUG:
705 		die("Kernel bug detected", regs);
706 		break;
707 	default:
708 		die_if_kernel("Break instruction in kernel code", regs);
709 		force_sig(SIGTRAP, current);
710 	}
711 
712 out_sigsegv:
713 	force_sig(SIGSEGV, current);
714 }
715 
716 asmlinkage void do_tr(struct pt_regs *regs)
717 {
718 	unsigned int opcode, tcode = 0;
719 	siginfo_t info;
720 
721 	if (get_user(opcode, (unsigned int __user *) exception_epc(regs)))
722 		goto out_sigsegv;
723 
724 	/* Immediate versions don't provide a code.  */
725 	if (!(opcode & OPCODE))
726 		tcode = ((opcode >> 6) & ((1 << 10) - 1));
727 
728 	/*
729 	 * (A short test says that IRIX 5.3 sends SIGTRAP for all trap
730 	 * insns, even for trap codes that indicate arithmetic failures.
731 	 * Weird ...)
732 	 * But should we continue the brokenness???  --macro
733 	 */
734 	switch (tcode) {
735 	case BRK_OVERFLOW:
736 	case BRK_DIVZERO:
737 		die_if_kernel("Trap instruction in kernel code", regs);
738 		if (tcode == BRK_DIVZERO)
739 			info.si_code = FPE_INTDIV;
740 		else
741 			info.si_code = FPE_INTOVF;
742 		info.si_signo = SIGFPE;
743 		info.si_errno = 0;
744 		info.si_addr = (void __user *) regs->cp0_epc;
745 		force_sig_info(SIGFPE, &info, current);
746 		break;
747 	case BRK_BUG:
748 		die("Kernel bug detected", regs);
749 		break;
750 	default:
751 		die_if_kernel("Trap instruction in kernel code", regs);
752 		force_sig(SIGTRAP, current);
753 	}
754 
755 out_sigsegv:
756 	force_sig(SIGSEGV, current);
757 }
758 
759 asmlinkage void do_ri(struct pt_regs *regs)
760 {
761 	die_if_kernel("Reserved instruction in kernel code", regs);
762 
763 	if (!cpu_has_llsc)
764 		if (!simulate_llsc(regs))
765 			return;
766 
767 	if (!simulate_rdhwr(regs))
768 		return;
769 
770 	force_sig(SIGILL, current);
771 }
772 
773 asmlinkage void do_cpu(struct pt_regs *regs)
774 {
775 	unsigned int cpid;
776 
777 	die_if_kernel("do_cpu invoked from kernel context!", regs);
778 
779 	cpid = (regs->cp0_cause >> CAUSEB_CE) & 3;
780 
781 	switch (cpid) {
782 	case 0:
783 		if (!cpu_has_llsc)
784 			if (!simulate_llsc(regs))
785 				return;
786 
787 		if (!simulate_rdhwr(regs))
788 			return;
789 
790 		break;
791 
792 	case 1:
793 		preempt_disable();
794 
795 		own_fpu();
796 		if (used_math()) {	/* Using the FPU again.  */
797 			restore_fp(current);
798 		} else {			/* First time FPU user.  */
799 			init_fpu();
800 			set_used_math();
801 		}
802 
803 		if (cpu_has_fpu) {
804 			preempt_enable();
805 		} else {
806 			int sig;
807 			preempt_enable();
808 			sig = fpu_emulator_cop1Handler(regs,
809 						&current->thread.fpu, 0);
810 			if (sig)
811 				force_sig(sig, current);
812 #ifdef CONFIG_MIPS_MT_FPAFF
813 			else {
814 			/*
815 			 * MIPS MT processors may have fewer FPU contexts
816 			 * than CPU threads. If we've emulated more than
817 			 * some threshold number of instructions, force
818 			 * migration to a "CPU" that has FP support.
819 			 */
820 			 if(mt_fpemul_threshold > 0
821 			 && ((current->thread.emulated_fp++
822 			    > mt_fpemul_threshold))) {
823 			  /*
824 			   * If there's no FPU present, or if the
825 			   * application has already restricted
826 			   * the allowed set to exclude any CPUs
827 			   * with FPUs, we'll skip the procedure.
828 			   */
829 			  if (cpus_intersects(current->cpus_allowed,
830 			  			mt_fpu_cpumask)) {
831 			    cpumask_t tmask;
832 
833 			    cpus_and(tmask,
834 					current->thread.user_cpus_allowed,
835 					mt_fpu_cpumask);
836 			    set_cpus_allowed(current, tmask);
837 			    current->thread.mflags |= MF_FPUBOUND;
838 			  }
839 			 }
840 			}
841 #endif /* CONFIG_MIPS_MT_FPAFF */
842 		}
843 
844 		return;
845 
846 	case 2:
847 	case 3:
848 		die_if_kernel("do_cpu invoked from kernel context!", regs);
849 		break;
850 	}
851 
852 	force_sig(SIGILL, current);
853 }
854 
855 asmlinkage void do_mdmx(struct pt_regs *regs)
856 {
857 	force_sig(SIGILL, current);
858 }
859 
860 asmlinkage void do_watch(struct pt_regs *regs)
861 {
862 	/*
863 	 * We use the watch exception where available to detect stack
864 	 * overflows.
865 	 */
866 	dump_tlb_all();
867 	show_regs(regs);
868 	panic("Caught WATCH exception - probably caused by stack overflow.");
869 }
870 
871 asmlinkage void do_mcheck(struct pt_regs *regs)
872 {
873 	const int field = 2 * sizeof(unsigned long);
874 	int multi_match = regs->cp0_status & ST0_TS;
875 
876 	show_regs(regs);
877 
878 	if (multi_match) {
879 		printk("Index   : %0x\n", read_c0_index());
880 		printk("Pagemask: %0x\n", read_c0_pagemask());
881 		printk("EntryHi : %0*lx\n", field, read_c0_entryhi());
882 		printk("EntryLo0: %0*lx\n", field, read_c0_entrylo0());
883 		printk("EntryLo1: %0*lx\n", field, read_c0_entrylo1());
884 		printk("\n");
885 		dump_tlb_all();
886 	}
887 
888 	show_code((unsigned int *) regs->cp0_epc);
889 
890 	/*
891 	 * Some chips may have other causes of machine check (e.g. SB1
892 	 * graduation timer)
893 	 */
894 	panic("Caught Machine Check exception - %scaused by multiple "
895 	      "matching entries in the TLB.",
896 	      (multi_match) ? "" : "not ");
897 }
898 
899 asmlinkage void do_mt(struct pt_regs *regs)
900 {
901 	int subcode;
902 
903 	subcode = (read_vpe_c0_vpecontrol() & VPECONTROL_EXCPT)
904 			>> VPECONTROL_EXCPT_SHIFT;
905 	switch (subcode) {
906 	case 0:
907 		printk(KERN_DEBUG "Thread Underflow\n");
908 		break;
909 	case 1:
910 		printk(KERN_DEBUG "Thread Overflow\n");
911 		break;
912 	case 2:
913 		printk(KERN_DEBUG "Invalid YIELD Qualifier\n");
914 		break;
915 	case 3:
916 		printk(KERN_DEBUG "Gating Storage Exception\n");
917 		break;
918 	case 4:
919 		printk(KERN_DEBUG "YIELD Scheduler Exception\n");
920 		break;
921 	case 5:
922 		printk(KERN_DEBUG "Gating Storage Schedulier Exception\n");
923 		break;
924 	default:
925 		printk(KERN_DEBUG "*** UNKNOWN THREAD EXCEPTION %d ***\n",
926 			subcode);
927 		break;
928 	}
929 	die_if_kernel("MIPS MT Thread exception in kernel", regs);
930 
931 	force_sig(SIGILL, current);
932 }
933 
934 
935 asmlinkage void do_dsp(struct pt_regs *regs)
936 {
937 	if (cpu_has_dsp)
938 		panic("Unexpected DSP exception\n");
939 
940 	force_sig(SIGILL, current);
941 }
942 
943 asmlinkage void do_reserved(struct pt_regs *regs)
944 {
945 	/*
946 	 * Game over - no way to handle this if it ever occurs.  Most probably
947 	 * caused by a new unknown cpu type or after another deadly
948 	 * hard/software error.
949 	 */
950 	show_regs(regs);
951 	panic("Caught reserved exception %ld - should not happen.",
952 	      (regs->cp0_cause & 0x7f) >> 2);
953 }
954 
955 asmlinkage void do_default_vi(struct pt_regs *regs)
956 {
957 	show_regs(regs);
958 	panic("Caught unexpected vectored interrupt.");
959 }
960 
961 /*
962  * Some MIPS CPUs can enable/disable for cache parity detection, but do
963  * it different ways.
964  */
965 static inline void parity_protection_init(void)
966 {
967 	switch (current_cpu_data.cputype) {
968 	case CPU_24K:
969 	case CPU_34K:
970 	case CPU_5KC:
971 		write_c0_ecc(0x80000000);
972 		back_to_back_c0_hazard();
973 		/* Set the PE bit (bit 31) in the c0_errctl register. */
974 		printk(KERN_INFO "Cache parity protection %sabled\n",
975 		       (read_c0_ecc() & 0x80000000) ? "en" : "dis");
976 		break;
977 	case CPU_20KC:
978 	case CPU_25KF:
979 		/* Clear the DE bit (bit 16) in the c0_status register. */
980 		printk(KERN_INFO "Enable cache parity protection for "
981 		       "MIPS 20KC/25KF CPUs.\n");
982 		clear_c0_status(ST0_DE);
983 		break;
984 	default:
985 		break;
986 	}
987 }
988 
989 asmlinkage void cache_parity_error(void)
990 {
991 	const int field = 2 * sizeof(unsigned long);
992 	unsigned int reg_val;
993 
994 	/* For the moment, report the problem and hang. */
995 	printk("Cache error exception:\n");
996 	printk("cp0_errorepc == %0*lx\n", field, read_c0_errorepc());
997 	reg_val = read_c0_cacheerr();
998 	printk("c0_cacheerr == %08x\n", reg_val);
999 
1000 	printk("Decoded c0_cacheerr: %s cache fault in %s reference.\n",
1001 	       reg_val & (1<<30) ? "secondary" : "primary",
1002 	       reg_val & (1<<31) ? "data" : "insn");
1003 	printk("Error bits: %s%s%s%s%s%s%s\n",
1004 	       reg_val & (1<<29) ? "ED " : "",
1005 	       reg_val & (1<<28) ? "ET " : "",
1006 	       reg_val & (1<<26) ? "EE " : "",
1007 	       reg_val & (1<<25) ? "EB " : "",
1008 	       reg_val & (1<<24) ? "EI " : "",
1009 	       reg_val & (1<<23) ? "E1 " : "",
1010 	       reg_val & (1<<22) ? "E0 " : "");
1011 	printk("IDX: 0x%08x\n", reg_val & ((1<<22)-1));
1012 
1013 #if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
1014 	if (reg_val & (1<<22))
1015 		printk("DErrAddr0: 0x%0*lx\n", field, read_c0_derraddr0());
1016 
1017 	if (reg_val & (1<<23))
1018 		printk("DErrAddr1: 0x%0*lx\n", field, read_c0_derraddr1());
1019 #endif
1020 
1021 	panic("Can't handle the cache error!");
1022 }
1023 
1024 /*
1025  * SDBBP EJTAG debug exception handler.
1026  * We skip the instruction and return to the next instruction.
1027  */
1028 void ejtag_exception_handler(struct pt_regs *regs)
1029 {
1030 	const int field = 2 * sizeof(unsigned long);
1031 	unsigned long depc, old_epc;
1032 	unsigned int debug;
1033 
1034 	printk(KERN_DEBUG "SDBBP EJTAG debug exception - not handled yet, just ignored!\n");
1035 	depc = read_c0_depc();
1036 	debug = read_c0_debug();
1037 	printk(KERN_DEBUG "c0_depc = %0*lx, DEBUG = %08x\n", field, depc, debug);
1038 	if (debug & 0x80000000) {
1039 		/*
1040 		 * In branch delay slot.
1041 		 * We cheat a little bit here and use EPC to calculate the
1042 		 * debug return address (DEPC). EPC is restored after the
1043 		 * calculation.
1044 		 */
1045 		old_epc = regs->cp0_epc;
1046 		regs->cp0_epc = depc;
1047 		__compute_return_epc(regs);
1048 		depc = regs->cp0_epc;
1049 		regs->cp0_epc = old_epc;
1050 	} else
1051 		depc += 4;
1052 	write_c0_depc(depc);
1053 
1054 #if 0
1055 	printk(KERN_DEBUG "\n\n----- Enable EJTAG single stepping ----\n\n");
1056 	write_c0_debug(debug | 0x100);
1057 #endif
1058 }
1059 
1060 /*
1061  * NMI exception handler.
1062  */
1063 void nmi_exception_handler(struct pt_regs *regs)
1064 {
1065 #ifdef CONFIG_MIPS_MT_SMTC
1066 	unsigned long dvpret = dvpe();
1067 	bust_spinlocks(1);
1068 	printk("NMI taken!!!!\n");
1069 	mips_mt_regdump(dvpret);
1070 #else
1071 	bust_spinlocks(1);
1072 	printk("NMI taken!!!!\n");
1073 #endif /* CONFIG_MIPS_MT_SMTC */
1074 	die("NMI", regs);
1075 	while(1) ;
1076 }
1077 
1078 #define VECTORSPACING 0x100	/* for EI/VI mode */
1079 
1080 unsigned long ebase;
1081 unsigned long exception_handlers[32];
1082 unsigned long vi_handlers[64];
1083 
1084 /*
1085  * As a side effect of the way this is implemented we're limited
1086  * to interrupt handlers in the address range from
1087  * KSEG0 <= x < KSEG0 + 256mb on the Nevada.  Oh well ...
1088  */
1089 void *set_except_vector(int n, void *addr)
1090 {
1091 	unsigned long handler = (unsigned long) addr;
1092 	unsigned long old_handler = exception_handlers[n];
1093 
1094 	exception_handlers[n] = handler;
1095 	if (n == 0 && cpu_has_divec) {
1096 		*(volatile u32 *)(ebase + 0x200) = 0x08000000 |
1097 		                                 (0x03ffffff & (handler >> 2));
1098 		flush_icache_range(ebase + 0x200, ebase + 0x204);
1099 	}
1100 	return (void *)old_handler;
1101 }
1102 
1103 #ifdef CONFIG_CPU_MIPSR2_SRS
1104 /*
1105  * MIPSR2 shadow register set allocation
1106  * FIXME: SMP...
1107  */
1108 
1109 static struct shadow_registers {
1110 	/*
1111 	 * Number of shadow register sets supported
1112 	 */
1113 	unsigned long sr_supported;
1114 	/*
1115 	 * Bitmap of allocated shadow registers
1116 	 */
1117 	unsigned long sr_allocated;
1118 } shadow_registers;
1119 
1120 static void mips_srs_init(void)
1121 {
1122 	shadow_registers.sr_supported = ((read_c0_srsctl() >> 26) & 0x0f) + 1;
1123 	printk(KERN_INFO "%ld MIPSR2 register sets available\n",
1124 	       shadow_registers.sr_supported);
1125 	shadow_registers.sr_allocated = 1;	/* Set 0 used by kernel */
1126 }
1127 
1128 int mips_srs_max(void)
1129 {
1130 	return shadow_registers.sr_supported;
1131 }
1132 
1133 int mips_srs_alloc(void)
1134 {
1135 	struct shadow_registers *sr = &shadow_registers;
1136 	int set;
1137 
1138 again:
1139 	set = find_first_zero_bit(&sr->sr_allocated, sr->sr_supported);
1140 	if (set >= sr->sr_supported)
1141 		return -1;
1142 
1143 	if (test_and_set_bit(set, &sr->sr_allocated))
1144 		goto again;
1145 
1146 	return set;
1147 }
1148 
1149 void mips_srs_free(int set)
1150 {
1151 	struct shadow_registers *sr = &shadow_registers;
1152 
1153 	clear_bit(set, &sr->sr_allocated);
1154 }
1155 
1156 static void *set_vi_srs_handler(int n, void *addr, int srs)
1157 {
1158 	unsigned long handler;
1159 	unsigned long old_handler = vi_handlers[n];
1160 	u32 *w;
1161 	unsigned char *b;
1162 
1163 	if (!cpu_has_veic && !cpu_has_vint)
1164 		BUG();
1165 
1166 	if (addr == NULL) {
1167 		handler = (unsigned long) do_default_vi;
1168 		srs = 0;
1169 	} else
1170 		handler = (unsigned long) addr;
1171 	vi_handlers[n] = (unsigned long) addr;
1172 
1173 	b = (unsigned char *)(ebase + 0x200 + n*VECTORSPACING);
1174 
1175 	if (srs >= mips_srs_max())
1176 		panic("Shadow register set %d not supported", srs);
1177 
1178 	if (cpu_has_veic) {
1179 		if (board_bind_eic_interrupt)
1180 			board_bind_eic_interrupt (n, srs);
1181 	} else if (cpu_has_vint) {
1182 		/* SRSMap is only defined if shadow sets are implemented */
1183 		if (mips_srs_max() > 1)
1184 			change_c0_srsmap (0xf << n*4, srs << n*4);
1185 	}
1186 
1187 	if (srs == 0) {
1188 		/*
1189 		 * If no shadow set is selected then use the default handler
1190 		 * that does normal register saving and a standard interrupt exit
1191 		 */
1192 
1193 		extern char except_vec_vi, except_vec_vi_lui;
1194 		extern char except_vec_vi_ori, except_vec_vi_end;
1195 #ifdef CONFIG_MIPS_MT_SMTC
1196 		/*
1197 		 * We need to provide the SMTC vectored interrupt handler
1198 		 * not only with the address of the handler, but with the
1199 		 * Status.IM bit to be masked before going there.
1200 		 */
1201 		extern char except_vec_vi_mori;
1202 		const int mori_offset = &except_vec_vi_mori - &except_vec_vi;
1203 #endif /* CONFIG_MIPS_MT_SMTC */
1204 		const int handler_len = &except_vec_vi_end - &except_vec_vi;
1205 		const int lui_offset = &except_vec_vi_lui - &except_vec_vi;
1206 		const int ori_offset = &except_vec_vi_ori - &except_vec_vi;
1207 
1208 		if (handler_len > VECTORSPACING) {
1209 			/*
1210 			 * Sigh... panicing won't help as the console
1211 			 * is probably not configured :(
1212 			 */
1213 			panic ("VECTORSPACING too small");
1214 		}
1215 
1216 		memcpy (b, &except_vec_vi, handler_len);
1217 #ifdef CONFIG_MIPS_MT_SMTC
1218 		if (n > 7)
1219 			printk("Vector index %d exceeds SMTC maximum\n", n);
1220 		w = (u32 *)(b + mori_offset);
1221 		*w = (*w & 0xffff0000) | (0x100 << n);
1222 #endif /* CONFIG_MIPS_MT_SMTC */
1223 		w = (u32 *)(b + lui_offset);
1224 		*w = (*w & 0xffff0000) | (((u32)handler >> 16) & 0xffff);
1225 		w = (u32 *)(b + ori_offset);
1226 		*w = (*w & 0xffff0000) | ((u32)handler & 0xffff);
1227 		flush_icache_range((unsigned long)b, (unsigned long)(b+handler_len));
1228 	}
1229 	else {
1230 		/*
1231 		 * In other cases jump directly to the interrupt handler
1232 		 *
1233 		 * It is the handlers responsibility to save registers if required
1234 		 * (eg hi/lo) and return from the exception using "eret"
1235 		 */
1236 		w = (u32 *)b;
1237 		*w++ = 0x08000000 | (((u32)handler >> 2) & 0x03fffff); /* j handler */
1238 		*w = 0;
1239 		flush_icache_range((unsigned long)b, (unsigned long)(b+8));
1240 	}
1241 
1242 	return (void *)old_handler;
1243 }
1244 
1245 void *set_vi_handler(int n, void *addr)
1246 {
1247 	return set_vi_srs_handler(n, addr, 0);
1248 }
1249 
1250 #else
1251 
1252 static inline void mips_srs_init(void)
1253 {
1254 }
1255 
1256 #endif /* CONFIG_CPU_MIPSR2_SRS */
1257 
1258 /*
1259  * This is used by native signal handling
1260  */
1261 asmlinkage int (*save_fp_context)(struct sigcontext *sc);
1262 asmlinkage int (*restore_fp_context)(struct sigcontext *sc);
1263 
1264 extern asmlinkage int _save_fp_context(struct sigcontext *sc);
1265 extern asmlinkage int _restore_fp_context(struct sigcontext *sc);
1266 
1267 extern asmlinkage int fpu_emulator_save_context(struct sigcontext *sc);
1268 extern asmlinkage int fpu_emulator_restore_context(struct sigcontext *sc);
1269 
1270 #ifdef CONFIG_SMP
1271 static int smp_save_fp_context(struct sigcontext *sc)
1272 {
1273 	return cpu_has_fpu
1274 	       ? _save_fp_context(sc)
1275 	       : fpu_emulator_save_context(sc);
1276 }
1277 
1278 static int smp_restore_fp_context(struct sigcontext *sc)
1279 {
1280 	return cpu_has_fpu
1281 	       ? _restore_fp_context(sc)
1282 	       : fpu_emulator_restore_context(sc);
1283 }
1284 #endif
1285 
1286 static inline void signal_init(void)
1287 {
1288 #ifdef CONFIG_SMP
1289 	/* For now just do the cpu_has_fpu check when the functions are invoked */
1290 	save_fp_context = smp_save_fp_context;
1291 	restore_fp_context = smp_restore_fp_context;
1292 #else
1293 	if (cpu_has_fpu) {
1294 		save_fp_context = _save_fp_context;
1295 		restore_fp_context = _restore_fp_context;
1296 	} else {
1297 		save_fp_context = fpu_emulator_save_context;
1298 		restore_fp_context = fpu_emulator_restore_context;
1299 	}
1300 #endif
1301 }
1302 
1303 #ifdef CONFIG_MIPS32_COMPAT
1304 
1305 /*
1306  * This is used by 32-bit signal stuff on the 64-bit kernel
1307  */
1308 asmlinkage int (*save_fp_context32)(struct sigcontext32 *sc);
1309 asmlinkage int (*restore_fp_context32)(struct sigcontext32 *sc);
1310 
1311 extern asmlinkage int _save_fp_context32(struct sigcontext32 *sc);
1312 extern asmlinkage int _restore_fp_context32(struct sigcontext32 *sc);
1313 
1314 extern asmlinkage int fpu_emulator_save_context32(struct sigcontext32 *sc);
1315 extern asmlinkage int fpu_emulator_restore_context32(struct sigcontext32 *sc);
1316 
1317 static inline void signal32_init(void)
1318 {
1319 	if (cpu_has_fpu) {
1320 		save_fp_context32 = _save_fp_context32;
1321 		restore_fp_context32 = _restore_fp_context32;
1322 	} else {
1323 		save_fp_context32 = fpu_emulator_save_context32;
1324 		restore_fp_context32 = fpu_emulator_restore_context32;
1325 	}
1326 }
1327 #endif
1328 
1329 extern void cpu_cache_init(void);
1330 extern void tlb_init(void);
1331 extern void flush_tlb_handlers(void);
1332 
1333 void __init per_cpu_trap_init(void)
1334 {
1335 	unsigned int cpu = smp_processor_id();
1336 	unsigned int status_set = ST0_CU0;
1337 #ifdef CONFIG_MIPS_MT_SMTC
1338 	int secondaryTC = 0;
1339 	int bootTC = (cpu == 0);
1340 
1341 	/*
1342 	 * Only do per_cpu_trap_init() for first TC of Each VPE.
1343 	 * Note that this hack assumes that the SMTC init code
1344 	 * assigns TCs consecutively and in ascending order.
1345 	 */
1346 
1347 	if (((read_c0_tcbind() & TCBIND_CURTC) != 0) &&
1348 	    ((read_c0_tcbind() & TCBIND_CURVPE) == cpu_data[cpu - 1].vpe_id))
1349 		secondaryTC = 1;
1350 #endif /* CONFIG_MIPS_MT_SMTC */
1351 
1352 	/*
1353 	 * Disable coprocessors and select 32-bit or 64-bit addressing
1354 	 * and the 16/32 or 32/32 FPR register model.  Reset the BEV
1355 	 * flag that some firmware may have left set and the TS bit (for
1356 	 * IP27).  Set XX for ISA IV code to work.
1357 	 */
1358 #ifdef CONFIG_64BIT
1359 	status_set |= ST0_FR|ST0_KX|ST0_SX|ST0_UX;
1360 #endif
1361 	if (current_cpu_data.isa_level == MIPS_CPU_ISA_IV)
1362 		status_set |= ST0_XX;
1363 	change_c0_status(ST0_CU|ST0_MX|ST0_RE|ST0_FR|ST0_BEV|ST0_TS|ST0_KX|ST0_SX|ST0_UX,
1364 			 status_set);
1365 
1366 	if (cpu_has_dsp)
1367 		set_c0_status(ST0_MX);
1368 
1369 #ifdef CONFIG_CPU_MIPSR2
1370 	write_c0_hwrena (0x0000000f); /* Allow rdhwr to all registers */
1371 #endif
1372 
1373 #ifdef CONFIG_MIPS_MT_SMTC
1374 	if (!secondaryTC) {
1375 #endif /* CONFIG_MIPS_MT_SMTC */
1376 
1377 	/*
1378 	 * Interrupt handling.
1379 	 */
1380 	if (cpu_has_veic || cpu_has_vint) {
1381 		write_c0_ebase (ebase);
1382 		/* Setting vector spacing enables EI/VI mode  */
1383 		change_c0_intctl (0x3e0, VECTORSPACING);
1384 	}
1385 	if (cpu_has_divec) {
1386 		if (cpu_has_mipsmt) {
1387 			unsigned int vpflags = dvpe();
1388 			set_c0_cause(CAUSEF_IV);
1389 			evpe(vpflags);
1390 		} else
1391 			set_c0_cause(CAUSEF_IV);
1392 	}
1393 #ifdef CONFIG_MIPS_MT_SMTC
1394 	}
1395 #endif /* CONFIG_MIPS_MT_SMTC */
1396 
1397 	cpu_data[cpu].asid_cache = ASID_FIRST_VERSION;
1398 	TLBMISS_HANDLER_SETUP();
1399 
1400 	atomic_inc(&init_mm.mm_count);
1401 	current->active_mm = &init_mm;
1402 	BUG_ON(current->mm);
1403 	enter_lazy_tlb(&init_mm, current);
1404 
1405 #ifdef CONFIG_MIPS_MT_SMTC
1406 	if (bootTC) {
1407 #endif /* CONFIG_MIPS_MT_SMTC */
1408 		cpu_cache_init();
1409 		tlb_init();
1410 #ifdef CONFIG_MIPS_MT_SMTC
1411 	}
1412 #endif /* CONFIG_MIPS_MT_SMTC */
1413 }
1414 
1415 /* Install CPU exception handler */
1416 void __init set_handler (unsigned long offset, void *addr, unsigned long size)
1417 {
1418 	memcpy((void *)(ebase + offset), addr, size);
1419 	flush_icache_range(ebase + offset, ebase + offset + size);
1420 }
1421 
1422 /* Install uncached CPU exception handler */
1423 void __init set_uncached_handler (unsigned long offset, void *addr, unsigned long size)
1424 {
1425 #ifdef CONFIG_32BIT
1426 	unsigned long uncached_ebase = KSEG1ADDR(ebase);
1427 #endif
1428 #ifdef CONFIG_64BIT
1429 	unsigned long uncached_ebase = TO_UNCAC(ebase);
1430 #endif
1431 
1432 	memcpy((void *)(uncached_ebase + offset), addr, size);
1433 }
1434 
1435 static int __initdata rdhwr_noopt;
1436 static int __init set_rdhwr_noopt(char *str)
1437 {
1438 	rdhwr_noopt = 1;
1439 	return 1;
1440 }
1441 
1442 __setup("rdhwr_noopt", set_rdhwr_noopt);
1443 
1444 void __init trap_init(void)
1445 {
1446 	extern char except_vec3_generic, except_vec3_r4000;
1447 	extern char except_vec4;
1448 	unsigned long i;
1449 
1450 	if (cpu_has_veic || cpu_has_vint)
1451 		ebase = (unsigned long) alloc_bootmem_low_pages (0x200 + VECTORSPACING*64);
1452 	else
1453 		ebase = CAC_BASE;
1454 
1455 	mips_srs_init();
1456 
1457 	per_cpu_trap_init();
1458 
1459 	/*
1460 	 * Copy the generic exception handlers to their final destination.
1461 	 * This will be overriden later as suitable for a particular
1462 	 * configuration.
1463 	 */
1464 	set_handler(0x180, &except_vec3_generic, 0x80);
1465 
1466 	/*
1467 	 * Setup default vectors
1468 	 */
1469 	for (i = 0; i <= 31; i++)
1470 		set_except_vector(i, handle_reserved);
1471 
1472 	/*
1473 	 * Copy the EJTAG debug exception vector handler code to it's final
1474 	 * destination.
1475 	 */
1476 	if (cpu_has_ejtag && board_ejtag_handler_setup)
1477 		board_ejtag_handler_setup ();
1478 
1479 	/*
1480 	 * Only some CPUs have the watch exceptions.
1481 	 */
1482 	if (cpu_has_watch)
1483 		set_except_vector(23, handle_watch);
1484 
1485 	/*
1486 	 * Initialise interrupt handlers
1487 	 */
1488 	if (cpu_has_veic || cpu_has_vint) {
1489 		int nvec = cpu_has_veic ? 64 : 8;
1490 		for (i = 0; i < nvec; i++)
1491 			set_vi_handler(i, NULL);
1492 	}
1493 	else if (cpu_has_divec)
1494 		set_handler(0x200, &except_vec4, 0x8);
1495 
1496 	/*
1497 	 * Some CPUs can enable/disable for cache parity detection, but does
1498 	 * it different ways.
1499 	 */
1500 	parity_protection_init();
1501 
1502 	/*
1503 	 * The Data Bus Errors / Instruction Bus Errors are signaled
1504 	 * by external hardware.  Therefore these two exceptions
1505 	 * may have board specific handlers.
1506 	 */
1507 	if (board_be_init)
1508 		board_be_init();
1509 
1510 	set_except_vector(0, handle_int);
1511 	set_except_vector(1, handle_tlbm);
1512 	set_except_vector(2, handle_tlbl);
1513 	set_except_vector(3, handle_tlbs);
1514 
1515 	set_except_vector(4, handle_adel);
1516 	set_except_vector(5, handle_ades);
1517 
1518 	set_except_vector(6, handle_ibe);
1519 	set_except_vector(7, handle_dbe);
1520 
1521 	set_except_vector(8, handle_sys);
1522 	set_except_vector(9, handle_bp);
1523 	set_except_vector(10, rdhwr_noopt ? handle_ri :
1524 			  (cpu_has_vtag_icache ?
1525 			   handle_ri_rdhwr_vivt : handle_ri_rdhwr));
1526 	set_except_vector(11, handle_cpu);
1527 	set_except_vector(12, handle_ov);
1528 	set_except_vector(13, handle_tr);
1529 
1530 	if (current_cpu_data.cputype == CPU_R6000 ||
1531 	    current_cpu_data.cputype == CPU_R6000A) {
1532 		/*
1533 		 * The R6000 is the only R-series CPU that features a machine
1534 		 * check exception (similar to the R4000 cache error) and
1535 		 * unaligned ldc1/sdc1 exception.  The handlers have not been
1536 		 * written yet.  Well, anyway there is no R6000 machine on the
1537 		 * current list of targets for Linux/MIPS.
1538 		 * (Duh, crap, there is someone with a triple R6k machine)
1539 		 */
1540 		//set_except_vector(14, handle_mc);
1541 		//set_except_vector(15, handle_ndc);
1542 	}
1543 
1544 
1545 	if (board_nmi_handler_setup)
1546 		board_nmi_handler_setup();
1547 
1548 	if (cpu_has_fpu && !cpu_has_nofpuex)
1549 		set_except_vector(15, handle_fpe);
1550 
1551 	set_except_vector(22, handle_mdmx);
1552 
1553 	if (cpu_has_mcheck)
1554 		set_except_vector(24, handle_mcheck);
1555 
1556 	if (cpu_has_mipsmt)
1557 		set_except_vector(25, handle_mt);
1558 
1559 	if (cpu_has_dsp)
1560 		set_except_vector(26, handle_dsp);
1561 
1562 	if (cpu_has_vce)
1563 		/* Special exception: R4[04]00 uses also the divec space. */
1564 		memcpy((void *)(CAC_BASE + 0x180), &except_vec3_r4000, 0x100);
1565 	else if (cpu_has_4kex)
1566 		memcpy((void *)(CAC_BASE + 0x180), &except_vec3_generic, 0x80);
1567 	else
1568 		memcpy((void *)(CAC_BASE + 0x080), &except_vec3_generic, 0x80);
1569 
1570 	signal_init();
1571 #ifdef CONFIG_MIPS32_COMPAT
1572 	signal32_init();
1573 #endif
1574 
1575 	flush_icache_range(ebase, ebase + 0x400);
1576 	flush_tlb_handlers();
1577 }
1578