xref: /linux/arch/mips/kernel/traps.c (revision 7b12b9137930eb821b68e1bfa11e9de692208620)
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/config.h>
15 #include <linux/init.h>
16 #include <linux/mm.h>
17 #include <linux/module.h>
18 #include <linux/sched.h>
19 #include <linux/smp.h>
20 #include <linux/smp_lock.h>
21 #include <linux/spinlock.h>
22 #include <linux/kallsyms.h>
23 #include <linux/bootmem.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 
45 extern asmlinkage void handle_int(void);
46 extern asmlinkage void handle_tlbm(void);
47 extern asmlinkage void handle_tlbl(void);
48 extern asmlinkage void handle_tlbs(void);
49 extern asmlinkage void handle_adel(void);
50 extern asmlinkage void handle_ades(void);
51 extern asmlinkage void handle_ibe(void);
52 extern asmlinkage void handle_dbe(void);
53 extern asmlinkage void handle_sys(void);
54 extern asmlinkage void handle_bp(void);
55 extern asmlinkage void handle_ri(void);
56 extern asmlinkage void handle_cpu(void);
57 extern asmlinkage void handle_ov(void);
58 extern asmlinkage void handle_tr(void);
59 extern asmlinkage void handle_fpe(void);
60 extern asmlinkage void handle_mdmx(void);
61 extern asmlinkage void handle_watch(void);
62 extern asmlinkage void handle_mt(void);
63 extern asmlinkage void handle_dsp(void);
64 extern asmlinkage void handle_mcheck(void);
65 extern asmlinkage void handle_reserved(void);
66 
67 extern int fpu_emulator_cop1Handler(struct pt_regs *xcp,
68 	struct mips_fpu_soft_struct *ctx);
69 
70 void (*board_be_init)(void);
71 int (*board_be_handler)(struct pt_regs *regs, int is_fixup);
72 void (*board_nmi_handler_setup)(void);
73 void (*board_ejtag_handler_setup)(void);
74 void (*board_bind_eic_interrupt)(int irq, int regset);
75 
76 /*
77  * These constant is for searching for possible module text segments.
78  * MODULE_RANGE is a guess of how much space is likely to be vmalloced.
79  */
80 #define MODULE_RANGE (8*1024*1024)
81 
82 /*
83  * This routine abuses get_user()/put_user() to reference pointers
84  * with at least a bit of error checking ...
85  */
86 void show_stack(struct task_struct *task, unsigned long *sp)
87 {
88 	const int field = 2 * sizeof(unsigned long);
89 	long stackdata;
90 	int i;
91 
92 	if (!sp) {
93 		if (task && task != current)
94 			sp = (unsigned long *) task->thread.reg29;
95 		else
96 			sp = (unsigned long *) &sp;
97 	}
98 
99 	printk("Stack :");
100 	i = 0;
101 	while ((unsigned long) sp & (PAGE_SIZE - 1)) {
102 		if (i && ((i % (64 / field)) == 0))
103 			printk("\n       ");
104 		if (i > 39) {
105 			printk(" ...");
106 			break;
107 		}
108 
109 		if (__get_user(stackdata, sp++)) {
110 			printk(" (Bad stack address)");
111 			break;
112 		}
113 
114 		printk(" %0*lx", field, stackdata);
115 		i++;
116 	}
117 	printk("\n");
118 }
119 
120 void show_trace(struct task_struct *task, unsigned long *stack)
121 {
122 	const int field = 2 * sizeof(unsigned long);
123 	unsigned long addr;
124 
125 	if (!stack) {
126 		if (task && task != current)
127 			stack = (unsigned long *) task->thread.reg29;
128 		else
129 			stack = (unsigned long *) &stack;
130 	}
131 
132 	printk("Call Trace:");
133 #ifdef CONFIG_KALLSYMS
134 	printk("\n");
135 #endif
136 	while (!kstack_end(stack)) {
137 		addr = *stack++;
138 		if (__kernel_text_address(addr)) {
139 			printk(" [<%0*lx>] ", field, addr);
140 			print_symbol("%s\n", addr);
141 		}
142 	}
143 	printk("\n");
144 }
145 
146 /*
147  * The architecture-independent dump_stack generator
148  */
149 void dump_stack(void)
150 {
151 	unsigned long stack;
152 
153 	show_trace(current, &stack);
154 }
155 
156 EXPORT_SYMBOL(dump_stack);
157 
158 void show_code(unsigned int *pc)
159 {
160 	long i;
161 
162 	printk("\nCode:");
163 
164 	for(i = -3 ; i < 6 ; i++) {
165 		unsigned int insn;
166 		if (__get_user(insn, pc + i)) {
167 			printk(" (Bad address in epc)\n");
168 			break;
169 		}
170 		printk("%c%08x%c", (i?' ':'<'), insn, (i?' ':'>'));
171 	}
172 }
173 
174 void show_regs(struct pt_regs *regs)
175 {
176 	const int field = 2 * sizeof(unsigned long);
177 	unsigned int cause = regs->cp0_cause;
178 	int i;
179 
180 	printk("Cpu %d\n", smp_processor_id());
181 
182 	/*
183 	 * Saved main processor registers
184 	 */
185 	for (i = 0; i < 32; ) {
186 		if ((i % 4) == 0)
187 			printk("$%2d   :", i);
188 		if (i == 0)
189 			printk(" %0*lx", field, 0UL);
190 		else if (i == 26 || i == 27)
191 			printk(" %*s", field, "");
192 		else
193 			printk(" %0*lx", field, regs->regs[i]);
194 
195 		i++;
196 		if ((i % 4) == 0)
197 			printk("\n");
198 	}
199 
200 	printk("Hi    : %0*lx\n", field, regs->hi);
201 	printk("Lo    : %0*lx\n", field, regs->lo);
202 
203 	/*
204 	 * Saved cp0 registers
205 	 */
206 	printk("epc   : %0*lx ", field, regs->cp0_epc);
207 	print_symbol("%s ", regs->cp0_epc);
208 	printk("    %s\n", print_tainted());
209 	printk("ra    : %0*lx ", field, regs->regs[31]);
210 	print_symbol("%s\n", regs->regs[31]);
211 
212 	printk("Status: %08x    ", (uint32_t) regs->cp0_status);
213 
214 	if (current_cpu_data.isa_level == MIPS_CPU_ISA_I) {
215 		if (regs->cp0_status & ST0_KUO)
216 			printk("KUo ");
217 		if (regs->cp0_status & ST0_IEO)
218 			printk("IEo ");
219 		if (regs->cp0_status & ST0_KUP)
220 			printk("KUp ");
221 		if (regs->cp0_status & ST0_IEP)
222 			printk("IEp ");
223 		if (regs->cp0_status & ST0_KUC)
224 			printk("KUc ");
225 		if (regs->cp0_status & ST0_IEC)
226 			printk("IEc ");
227 	} else {
228 		if (regs->cp0_status & ST0_KX)
229 			printk("KX ");
230 		if (regs->cp0_status & ST0_SX)
231 			printk("SX ");
232 		if (regs->cp0_status & ST0_UX)
233 			printk("UX ");
234 		switch (regs->cp0_status & ST0_KSU) {
235 		case KSU_USER:
236 			printk("USER ");
237 			break;
238 		case KSU_SUPERVISOR:
239 			printk("SUPERVISOR ");
240 			break;
241 		case KSU_KERNEL:
242 			printk("KERNEL ");
243 			break;
244 		default:
245 			printk("BAD_MODE ");
246 			break;
247 		}
248 		if (regs->cp0_status & ST0_ERL)
249 			printk("ERL ");
250 		if (regs->cp0_status & ST0_EXL)
251 			printk("EXL ");
252 		if (regs->cp0_status & ST0_IE)
253 			printk("IE ");
254 	}
255 	printk("\n");
256 
257 	printk("Cause : %08x\n", cause);
258 
259 	cause = (cause & CAUSEF_EXCCODE) >> CAUSEB_EXCCODE;
260 	if (1 <= cause && cause <= 5)
261 		printk("BadVA : %0*lx\n", field, regs->cp0_badvaddr);
262 
263 	printk("PrId  : %08x\n", read_c0_prid());
264 }
265 
266 void show_registers(struct pt_regs *regs)
267 {
268 	show_regs(regs);
269 	print_modules();
270 	printk("Process %s (pid: %d, threadinfo=%p, task=%p)\n",
271 	        current->comm, current->pid, current_thread_info(), current);
272 	show_stack(current, (long *) regs->regs[29]);
273 	show_trace(current, (long *) regs->regs[29]);
274 	show_code((unsigned int *) regs->cp0_epc);
275 	printk("\n");
276 }
277 
278 static DEFINE_SPINLOCK(die_lock);
279 
280 NORET_TYPE void ATTRIB_NORET die(const char * str, struct pt_regs * regs)
281 {
282 	static int die_counter;
283 #ifdef CONFIG_MIPS_MT_SMTC
284 	unsigned long dvpret = dvpe();
285 #endif /* CONFIG_MIPS_MT_SMTC */
286 
287 	console_verbose();
288 	spin_lock_irq(&die_lock);
289 	bust_spinlocks(1);
290 #ifdef CONFIG_MIPS_MT_SMTC
291 	mips_mt_regdump(dvpret);
292 #endif /* CONFIG_MIPS_MT_SMTC */
293 	printk("%s[#%d]:\n", str, ++die_counter);
294 	show_registers(regs);
295 	spin_unlock_irq(&die_lock);
296 	do_exit(SIGSEGV);
297 }
298 
299 extern const struct exception_table_entry __start___dbe_table[];
300 extern const struct exception_table_entry __stop___dbe_table[];
301 
302 void __declare_dbe_table(void)
303 {
304 	__asm__ __volatile__(
305 	".section\t__dbe_table,\"a\"\n\t"
306 	".previous"
307 	);
308 }
309 
310 /* Given an address, look for it in the exception tables. */
311 static const struct exception_table_entry *search_dbe_tables(unsigned long addr)
312 {
313 	const struct exception_table_entry *e;
314 
315 	e = search_extable(__start___dbe_table, __stop___dbe_table - 1, addr);
316 	if (!e)
317 		e = search_module_dbetables(addr);
318 	return e;
319 }
320 
321 asmlinkage void do_be(struct pt_regs *regs)
322 {
323 	const int field = 2 * sizeof(unsigned long);
324 	const struct exception_table_entry *fixup = NULL;
325 	int data = regs->cp0_cause & 4;
326 	int action = MIPS_BE_FATAL;
327 
328 	/* XXX For now.  Fixme, this searches the wrong table ...  */
329 	if (data && !user_mode(regs))
330 		fixup = search_dbe_tables(exception_epc(regs));
331 
332 	if (fixup)
333 		action = MIPS_BE_FIXUP;
334 
335 	if (board_be_handler)
336 		action = board_be_handler(regs, fixup != 0);
337 
338 	switch (action) {
339 	case MIPS_BE_DISCARD:
340 		return;
341 	case MIPS_BE_FIXUP:
342 		if (fixup) {
343 			regs->cp0_epc = fixup->nextinsn;
344 			return;
345 		}
346 		break;
347 	default:
348 		break;
349 	}
350 
351 	/*
352 	 * Assume it would be too dangerous to continue ...
353 	 */
354 	printk(KERN_ALERT "%s bus error, epc == %0*lx, ra == %0*lx\n",
355 	       data ? "Data" : "Instruction",
356 	       field, regs->cp0_epc, field, regs->regs[31]);
357 	die_if_kernel("Oops", regs);
358 	force_sig(SIGBUS, current);
359 }
360 
361 static inline int get_insn_opcode(struct pt_regs *regs, unsigned int *opcode)
362 {
363 	unsigned int __user *epc;
364 
365 	epc = (unsigned int __user *) regs->cp0_epc +
366 	      ((regs->cp0_cause & CAUSEF_BD) != 0);
367 	if (!get_user(*opcode, epc))
368 		return 0;
369 
370 	force_sig(SIGSEGV, current);
371 	return 1;
372 }
373 
374 /*
375  * ll/sc emulation
376  */
377 
378 #define OPCODE 0xfc000000
379 #define BASE   0x03e00000
380 #define RT     0x001f0000
381 #define OFFSET 0x0000ffff
382 #define LL     0xc0000000
383 #define SC     0xe0000000
384 #define SPEC3  0x7c000000
385 #define RD     0x0000f800
386 #define FUNC   0x0000003f
387 #define RDHWR  0x0000003b
388 
389 /*
390  * The ll_bit is cleared by r*_switch.S
391  */
392 
393 unsigned long ll_bit;
394 
395 static struct task_struct *ll_task = NULL;
396 
397 static inline void simulate_ll(struct pt_regs *regs, unsigned int opcode)
398 {
399 	unsigned long value, __user *vaddr;
400 	long offset;
401 	int signal = 0;
402 
403 	/*
404 	 * analyse the ll instruction that just caused a ri exception
405 	 * and put the referenced address to addr.
406 	 */
407 
408 	/* sign extend offset */
409 	offset = opcode & OFFSET;
410 	offset <<= 16;
411 	offset >>= 16;
412 
413 	vaddr = (unsigned long __user *)
414 	        ((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
415 
416 	if ((unsigned long)vaddr & 3) {
417 		signal = SIGBUS;
418 		goto sig;
419 	}
420 	if (get_user(value, vaddr)) {
421 		signal = SIGSEGV;
422 		goto sig;
423 	}
424 
425 	preempt_disable();
426 
427 	if (ll_task == NULL || ll_task == current) {
428 		ll_bit = 1;
429 	} else {
430 		ll_bit = 0;
431 	}
432 	ll_task = current;
433 
434 	preempt_enable();
435 
436 	compute_return_epc(regs);
437 
438 	regs->regs[(opcode & RT) >> 16] = value;
439 
440 	return;
441 
442 sig:
443 	force_sig(signal, current);
444 }
445 
446 static inline void simulate_sc(struct pt_regs *regs, unsigned int opcode)
447 {
448 	unsigned long __user *vaddr;
449 	unsigned long reg;
450 	long offset;
451 	int signal = 0;
452 
453 	/*
454 	 * analyse the sc instruction that just caused a ri exception
455 	 * and put the referenced address to addr.
456 	 */
457 
458 	/* sign extend offset */
459 	offset = opcode & OFFSET;
460 	offset <<= 16;
461 	offset >>= 16;
462 
463 	vaddr = (unsigned long __user *)
464 	        ((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
465 	reg = (opcode & RT) >> 16;
466 
467 	if ((unsigned long)vaddr & 3) {
468 		signal = SIGBUS;
469 		goto sig;
470 	}
471 
472 	preempt_disable();
473 
474 	if (ll_bit == 0 || ll_task != current) {
475 		compute_return_epc(regs);
476 		regs->regs[reg] = 0;
477 		preempt_enable();
478 		return;
479 	}
480 
481 	preempt_enable();
482 
483 	if (put_user(regs->regs[reg], vaddr)) {
484 		signal = SIGSEGV;
485 		goto sig;
486 	}
487 
488 	compute_return_epc(regs);
489 	regs->regs[reg] = 1;
490 
491 	return;
492 
493 sig:
494 	force_sig(signal, current);
495 }
496 
497 /*
498  * ll uses the opcode of lwc0 and sc uses the opcode of swc0.  That is both
499  * opcodes are supposed to result in coprocessor unusable exceptions if
500  * executed on ll/sc-less processors.  That's the theory.  In practice a
501  * few processors such as NEC's VR4100 throw reserved instruction exceptions
502  * instead, so we're doing the emulation thing in both exception handlers.
503  */
504 static inline int simulate_llsc(struct pt_regs *regs)
505 {
506 	unsigned int opcode;
507 
508 	if (unlikely(get_insn_opcode(regs, &opcode)))
509 		return -EFAULT;
510 
511 	if ((opcode & OPCODE) == LL) {
512 		simulate_ll(regs, opcode);
513 		return 0;
514 	}
515 	if ((opcode & OPCODE) == SC) {
516 		simulate_sc(regs, opcode);
517 		return 0;
518 	}
519 
520 	return -EFAULT;			/* Strange things going on ... */
521 }
522 
523 /*
524  * Simulate trapping 'rdhwr' instructions to provide user accessible
525  * registers not implemented in hardware.  The only current use of this
526  * is the thread area pointer.
527  */
528 static inline int simulate_rdhwr(struct pt_regs *regs)
529 {
530 	struct thread_info *ti = task_thread_info(current);
531 	unsigned int opcode;
532 
533 	if (unlikely(get_insn_opcode(regs, &opcode)))
534 		return -EFAULT;
535 
536 	if (unlikely(compute_return_epc(regs)))
537 		return -EFAULT;
538 
539 	if ((opcode & OPCODE) == SPEC3 && (opcode & FUNC) == RDHWR) {
540 		int rd = (opcode & RD) >> 11;
541 		int rt = (opcode & RT) >> 16;
542 		switch (rd) {
543 			case 29:
544 				regs->regs[rt] = ti->tp_value;
545 				return 0;
546 			default:
547 				return -EFAULT;
548 		}
549 	}
550 
551 	/* Not ours.  */
552 	return -EFAULT;
553 }
554 
555 asmlinkage void do_ov(struct pt_regs *regs)
556 {
557 	siginfo_t info;
558 
559 	die_if_kernel("Integer overflow", regs);
560 
561 	info.si_code = FPE_INTOVF;
562 	info.si_signo = SIGFPE;
563 	info.si_errno = 0;
564 	info.si_addr = (void __user *) regs->cp0_epc;
565 	force_sig_info(SIGFPE, &info, current);
566 }
567 
568 /*
569  * XXX Delayed fp exceptions when doing a lazy ctx switch XXX
570  */
571 asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
572 {
573 	if (fcr31 & FPU_CSR_UNI_X) {
574 		int sig;
575 
576 		preempt_disable();
577 
578 #ifdef CONFIG_PREEMPT
579 		if (!is_fpu_owner()) {
580 			/* We might lose fpu before disabling preempt... */
581 			own_fpu();
582 			BUG_ON(!used_math());
583 			restore_fp(current);
584 		}
585 #endif
586 		/*
587 		 * Unimplemented operation exception.  If we've got the full
588 		 * software emulator on-board, let's use it...
589 		 *
590 		 * Force FPU to dump state into task/thread context.  We're
591 		 * moving a lot of data here for what is probably a single
592 		 * instruction, but the alternative is to pre-decode the FP
593 		 * register operands before invoking the emulator, which seems
594 		 * a bit extreme for what should be an infrequent event.
595 		 */
596 		save_fp(current);
597 		/* Ensure 'resume' not overwrite saved fp context again. */
598 		lose_fpu();
599 
600 		preempt_enable();
601 
602 		/* Run the emulator */
603 		sig = fpu_emulator_cop1Handler (regs,
604 			&current->thread.fpu.soft);
605 
606 		preempt_disable();
607 
608 		own_fpu();	/* Using the FPU again.  */
609 		/*
610 		 * We can't allow the emulated instruction to leave any of
611 		 * the cause bit set in $fcr31.
612 		 */
613 		current->thread.fpu.soft.fcr31 &= ~FPU_CSR_ALL_X;
614 
615 		/* Restore the hardware register state */
616 		restore_fp(current);
617 
618 		preempt_enable();
619 
620 		/* If something went wrong, signal */
621 		if (sig)
622 			force_sig(sig, current);
623 
624 		return;
625 	}
626 
627 	force_sig(SIGFPE, current);
628 }
629 
630 asmlinkage void do_bp(struct pt_regs *regs)
631 {
632 	unsigned int opcode, bcode;
633 	siginfo_t info;
634 
635 	die_if_kernel("Break instruction in kernel code", regs);
636 
637 	if (get_insn_opcode(regs, &opcode))
638 		return;
639 
640 	/*
641 	 * There is the ancient bug in the MIPS assemblers that the break
642 	 * code starts left to bit 16 instead to bit 6 in the opcode.
643 	 * Gas is bug-compatible, but not always, grrr...
644 	 * We handle both cases with a simple heuristics.  --macro
645 	 */
646 	bcode = ((opcode >> 6) & ((1 << 20) - 1));
647 	if (bcode < (1 << 10))
648 		bcode <<= 10;
649 
650 	/*
651 	 * (A short test says that IRIX 5.3 sends SIGTRAP for all break
652 	 * insns, even for break codes that indicate arithmetic failures.
653 	 * Weird ...)
654 	 * But should we continue the brokenness???  --macro
655 	 */
656 	switch (bcode) {
657 	case BRK_OVERFLOW << 10:
658 	case BRK_DIVZERO << 10:
659 		if (bcode == (BRK_DIVZERO << 10))
660 			info.si_code = FPE_INTDIV;
661 		else
662 			info.si_code = FPE_INTOVF;
663 		info.si_signo = SIGFPE;
664 		info.si_errno = 0;
665 		info.si_addr = (void __user *) regs->cp0_epc;
666 		force_sig_info(SIGFPE, &info, current);
667 		break;
668 	default:
669 		force_sig(SIGTRAP, current);
670 	}
671 }
672 
673 asmlinkage void do_tr(struct pt_regs *regs)
674 {
675 	unsigned int opcode, tcode = 0;
676 	siginfo_t info;
677 
678 	die_if_kernel("Trap instruction in kernel code", regs);
679 
680 	if (get_insn_opcode(regs, &opcode))
681 		return;
682 
683 	/* Immediate versions don't provide a code.  */
684 	if (!(opcode & OPCODE))
685 		tcode = ((opcode >> 6) & ((1 << 10) - 1));
686 
687 	/*
688 	 * (A short test says that IRIX 5.3 sends SIGTRAP for all trap
689 	 * insns, even for trap codes that indicate arithmetic failures.
690 	 * Weird ...)
691 	 * But should we continue the brokenness???  --macro
692 	 */
693 	switch (tcode) {
694 	case BRK_OVERFLOW:
695 	case BRK_DIVZERO:
696 		if (tcode == BRK_DIVZERO)
697 			info.si_code = FPE_INTDIV;
698 		else
699 			info.si_code = FPE_INTOVF;
700 		info.si_signo = SIGFPE;
701 		info.si_errno = 0;
702 		info.si_addr = (void __user *) regs->cp0_epc;
703 		force_sig_info(SIGFPE, &info, current);
704 		break;
705 	default:
706 		force_sig(SIGTRAP, current);
707 	}
708 }
709 
710 asmlinkage void do_ri(struct pt_regs *regs)
711 {
712 	die_if_kernel("Reserved instruction in kernel code", regs);
713 
714 	if (!cpu_has_llsc)
715 		if (!simulate_llsc(regs))
716 			return;
717 
718 	if (!simulate_rdhwr(regs))
719 		return;
720 
721 	force_sig(SIGILL, current);
722 }
723 
724 asmlinkage void do_cpu(struct pt_regs *regs)
725 {
726 	unsigned int cpid;
727 
728 	die_if_kernel("do_cpu invoked from kernel context!", regs);
729 
730 	cpid = (regs->cp0_cause >> CAUSEB_CE) & 3;
731 
732 	switch (cpid) {
733 	case 0:
734 		if (!cpu_has_llsc)
735 			if (!simulate_llsc(regs))
736 				return;
737 
738 		if (!simulate_rdhwr(regs))
739 			return;
740 
741 		break;
742 
743 	case 1:
744 		preempt_disable();
745 
746 		own_fpu();
747 		if (used_math()) {	/* Using the FPU again.  */
748 			restore_fp(current);
749 		} else {			/* First time FPU user.  */
750 			init_fpu();
751 			set_used_math();
752 		}
753 
754 		preempt_enable();
755 
756 		if (!cpu_has_fpu) {
757 			int sig = fpu_emulator_cop1Handler(regs,
758 						&current->thread.fpu.soft);
759 			if (sig)
760 				force_sig(sig, current);
761 #ifdef CONFIG_MIPS_MT_FPAFF
762 			else {
763 			/*
764 			 * MIPS MT processors may have fewer FPU contexts
765 			 * than CPU threads. If we've emulated more than
766 			 * some threshold number of instructions, force
767 			 * migration to a "CPU" that has FP support.
768 			 */
769 			 if(mt_fpemul_threshold > 0
770 			 && ((current->thread.emulated_fp++
771 			    > mt_fpemul_threshold))) {
772 			  /*
773 			   * If there's no FPU present, or if the
774 			   * application has already restricted
775 			   * the allowed set to exclude any CPUs
776 			   * with FPUs, we'll skip the procedure.
777 			   */
778 			  if (cpus_intersects(current->cpus_allowed,
779 			  			mt_fpu_cpumask)) {
780 			    cpumask_t tmask;
781 
782 			    cpus_and(tmask,
783 					current->thread.user_cpus_allowed,
784 					mt_fpu_cpumask);
785 			    set_cpus_allowed(current, tmask);
786 			    current->thread.mflags |= MF_FPUBOUND;
787 			  }
788 			 }
789 			}
790 #endif /* CONFIG_MIPS_MT_FPAFF */
791 		}
792 
793 		return;
794 
795 	case 2:
796 	case 3:
797 		die_if_kernel("do_cpu invoked from kernel context!", regs);
798 		break;
799 	}
800 
801 	force_sig(SIGILL, current);
802 }
803 
804 asmlinkage void do_mdmx(struct pt_regs *regs)
805 {
806 	force_sig(SIGILL, current);
807 }
808 
809 asmlinkage void do_watch(struct pt_regs *regs)
810 {
811 	/*
812 	 * We use the watch exception where available to detect stack
813 	 * overflows.
814 	 */
815 	dump_tlb_all();
816 	show_regs(regs);
817 	panic("Caught WATCH exception - probably caused by stack overflow.");
818 }
819 
820 asmlinkage void do_mcheck(struct pt_regs *regs)
821 {
822 	show_regs(regs);
823 	dump_tlb_all();
824 	/*
825 	 * Some chips may have other causes of machine check (e.g. SB1
826 	 * graduation timer)
827 	 */
828 	panic("Caught Machine Check exception - %scaused by multiple "
829 	      "matching entries in the TLB.",
830 	      (regs->cp0_status & ST0_TS) ? "" : "not ");
831 }
832 
833 asmlinkage void do_mt(struct pt_regs *regs)
834 {
835 	int subcode;
836 
837 	die_if_kernel("MIPS MT Thread exception in kernel", regs);
838 
839 	subcode = (read_vpe_c0_vpecontrol() & VPECONTROL_EXCPT)
840 			>> VPECONTROL_EXCPT_SHIFT;
841 	switch (subcode) {
842 	case 0:
843 		printk(KERN_ERR "Thread Underflow\n");
844 		break;
845 	case 1:
846 		printk(KERN_ERR "Thread Overflow\n");
847 		break;
848 	case 2:
849 		printk(KERN_ERR "Invalid YIELD Qualifier\n");
850 		break;
851 	case 3:
852 		printk(KERN_ERR "Gating Storage Exception\n");
853 		break;
854 	case 4:
855 		printk(KERN_ERR "YIELD Scheduler Exception\n");
856 		break;
857 	case 5:
858 		printk(KERN_ERR "Gating Storage Schedulier Exception\n");
859 		break;
860 	default:
861 		printk(KERN_ERR "*** UNKNOWN THREAD EXCEPTION %d ***\n",
862 			subcode);
863 		break;
864 	}
865 	die_if_kernel("MIPS MT Thread exception in kernel", regs);
866 
867 	force_sig(SIGILL, current);
868 }
869 
870 
871 asmlinkage void do_dsp(struct pt_regs *regs)
872 {
873 	if (cpu_has_dsp)
874 		panic("Unexpected DSP exception\n");
875 
876 	force_sig(SIGILL, current);
877 }
878 
879 asmlinkage void do_reserved(struct pt_regs *regs)
880 {
881 	/*
882 	 * Game over - no way to handle this if it ever occurs.  Most probably
883 	 * caused by a new unknown cpu type or after another deadly
884 	 * hard/software error.
885 	 */
886 	show_regs(regs);
887 	panic("Caught reserved exception %ld - should not happen.",
888 	      (regs->cp0_cause & 0x7f) >> 2);
889 }
890 
891 asmlinkage void do_default_vi(struct pt_regs *regs)
892 {
893 	show_regs(regs);
894 	panic("Caught unexpected vectored interrupt.");
895 }
896 
897 /*
898  * Some MIPS CPUs can enable/disable for cache parity detection, but do
899  * it different ways.
900  */
901 static inline void parity_protection_init(void)
902 {
903 	switch (current_cpu_data.cputype) {
904 	case CPU_24K:
905 	case CPU_5KC:
906 		write_c0_ecc(0x80000000);
907 		back_to_back_c0_hazard();
908 		/* Set the PE bit (bit 31) in the c0_errctl register. */
909 		printk(KERN_INFO "Cache parity protection %sabled\n",
910 		       (read_c0_ecc() & 0x80000000) ? "en" : "dis");
911 		break;
912 	case CPU_20KC:
913 	case CPU_25KF:
914 		/* Clear the DE bit (bit 16) in the c0_status register. */
915 		printk(KERN_INFO "Enable cache parity protection for "
916 		       "MIPS 20KC/25KF CPUs.\n");
917 		clear_c0_status(ST0_DE);
918 		break;
919 	default:
920 		break;
921 	}
922 }
923 
924 asmlinkage void cache_parity_error(void)
925 {
926 	const int field = 2 * sizeof(unsigned long);
927 	unsigned int reg_val;
928 
929 	/* For the moment, report the problem and hang. */
930 	printk("Cache error exception:\n");
931 	printk("cp0_errorepc == %0*lx\n", field, read_c0_errorepc());
932 	reg_val = read_c0_cacheerr();
933 	printk("c0_cacheerr == %08x\n", reg_val);
934 
935 	printk("Decoded c0_cacheerr: %s cache fault in %s reference.\n",
936 	       reg_val & (1<<30) ? "secondary" : "primary",
937 	       reg_val & (1<<31) ? "data" : "insn");
938 	printk("Error bits: %s%s%s%s%s%s%s\n",
939 	       reg_val & (1<<29) ? "ED " : "",
940 	       reg_val & (1<<28) ? "ET " : "",
941 	       reg_val & (1<<26) ? "EE " : "",
942 	       reg_val & (1<<25) ? "EB " : "",
943 	       reg_val & (1<<24) ? "EI " : "",
944 	       reg_val & (1<<23) ? "E1 " : "",
945 	       reg_val & (1<<22) ? "E0 " : "");
946 	printk("IDX: 0x%08x\n", reg_val & ((1<<22)-1));
947 
948 #if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
949 	if (reg_val & (1<<22))
950 		printk("DErrAddr0: 0x%0*lx\n", field, read_c0_derraddr0());
951 
952 	if (reg_val & (1<<23))
953 		printk("DErrAddr1: 0x%0*lx\n", field, read_c0_derraddr1());
954 #endif
955 
956 	panic("Can't handle the cache error!");
957 }
958 
959 /*
960  * SDBBP EJTAG debug exception handler.
961  * We skip the instruction and return to the next instruction.
962  */
963 void ejtag_exception_handler(struct pt_regs *regs)
964 {
965 	const int field = 2 * sizeof(unsigned long);
966 	unsigned long depc, old_epc;
967 	unsigned int debug;
968 
969 	printk("SDBBP EJTAG debug exception - not handled yet, just ignored!\n");
970 	depc = read_c0_depc();
971 	debug = read_c0_debug();
972 	printk("c0_depc = %0*lx, DEBUG = %08x\n", field, depc, debug);
973 	if (debug & 0x80000000) {
974 		/*
975 		 * In branch delay slot.
976 		 * We cheat a little bit here and use EPC to calculate the
977 		 * debug return address (DEPC). EPC is restored after the
978 		 * calculation.
979 		 */
980 		old_epc = regs->cp0_epc;
981 		regs->cp0_epc = depc;
982 		__compute_return_epc(regs);
983 		depc = regs->cp0_epc;
984 		regs->cp0_epc = old_epc;
985 	} else
986 		depc += 4;
987 	write_c0_depc(depc);
988 
989 #if 0
990 	printk("\n\n----- Enable EJTAG single stepping ----\n\n");
991 	write_c0_debug(debug | 0x100);
992 #endif
993 }
994 
995 /*
996  * NMI exception handler.
997  */
998 void nmi_exception_handler(struct pt_regs *regs)
999 {
1000 #ifdef CONFIG_MIPS_MT_SMTC
1001 	unsigned long dvpret = dvpe();
1002 	bust_spinlocks(1);
1003 	printk("NMI taken!!!!\n");
1004 	mips_mt_regdump(dvpret);
1005 #else
1006 	bust_spinlocks(1);
1007 	printk("NMI taken!!!!\n");
1008 #endif /* CONFIG_MIPS_MT_SMTC */
1009 	die("NMI", regs);
1010 	while(1) ;
1011 }
1012 
1013 #define VECTORSPACING 0x100	/* for EI/VI mode */
1014 
1015 unsigned long ebase;
1016 unsigned long exception_handlers[32];
1017 unsigned long vi_handlers[64];
1018 
1019 /*
1020  * As a side effect of the way this is implemented we're limited
1021  * to interrupt handlers in the address range from
1022  * KSEG0 <= x < KSEG0 + 256mb on the Nevada.  Oh well ...
1023  */
1024 void *set_except_vector(int n, void *addr)
1025 {
1026 	unsigned long handler = (unsigned long) addr;
1027 	unsigned long old_handler = exception_handlers[n];
1028 
1029 	exception_handlers[n] = handler;
1030 	if (n == 0 && cpu_has_divec) {
1031 		*(volatile u32 *)(ebase + 0x200) = 0x08000000 |
1032 		                                 (0x03ffffff & (handler >> 2));
1033 		flush_icache_range(ebase + 0x200, ebase + 0x204);
1034 	}
1035 	return (void *)old_handler;
1036 }
1037 
1038 #ifdef CONFIG_CPU_MIPSR2
1039 /*
1040  * MIPSR2 shadow register set allocation
1041  * FIXME: SMP...
1042  */
1043 
1044 static struct shadow_registers {
1045 	/*
1046 	 * Number of shadow register sets supported
1047 	 */
1048 	unsigned long sr_supported;
1049 	/*
1050 	 * Bitmap of allocated shadow registers
1051 	 */
1052 	unsigned long sr_allocated;
1053 } shadow_registers;
1054 
1055 static void mips_srs_init(void)
1056 {
1057 #ifdef CONFIG_CPU_MIPSR2_SRS
1058 	shadow_registers.sr_supported = ((read_c0_srsctl() >> 26) & 0x0f) + 1;
1059 	printk(KERN_INFO "%d MIPSR2 register sets available\n",
1060 	       shadow_registers.sr_supported);
1061 #endif
1062 	shadow_registers.sr_allocated = 1;	/* Set 0 used by kernel */
1063 }
1064 
1065 int mips_srs_max(void)
1066 {
1067 	return shadow_registers.sr_supported;
1068 }
1069 
1070 int mips_srs_alloc(void)
1071 {
1072 	struct shadow_registers *sr = &shadow_registers;
1073 	int set;
1074 
1075 again:
1076 	set = find_first_zero_bit(&sr->sr_allocated, sr->sr_supported);
1077 	if (set >= sr->sr_supported)
1078 		return -1;
1079 
1080 	if (test_and_set_bit(set, &sr->sr_allocated))
1081 		goto again;
1082 
1083 	return set;
1084 }
1085 
1086 void mips_srs_free(int set)
1087 {
1088 	struct shadow_registers *sr = &shadow_registers;
1089 
1090 	clear_bit(set, &sr->sr_allocated);
1091 }
1092 
1093 static void *set_vi_srs_handler(int n, void *addr, int srs)
1094 {
1095 	unsigned long handler;
1096 	unsigned long old_handler = vi_handlers[n];
1097 	u32 *w;
1098 	unsigned char *b;
1099 
1100 	if (!cpu_has_veic && !cpu_has_vint)
1101 		BUG();
1102 
1103 	if (addr == NULL) {
1104 		handler = (unsigned long) do_default_vi;
1105 		srs = 0;
1106 	} else
1107 		handler = (unsigned long) addr;
1108 	vi_handlers[n] = (unsigned long) addr;
1109 
1110 	b = (unsigned char *)(ebase + 0x200 + n*VECTORSPACING);
1111 
1112 	if (srs >= mips_srs_max())
1113 		panic("Shadow register set %d not supported", srs);
1114 
1115 	if (cpu_has_veic) {
1116 		if (board_bind_eic_interrupt)
1117 			board_bind_eic_interrupt (n, srs);
1118 	} else if (cpu_has_vint) {
1119 		/* SRSMap is only defined if shadow sets are implemented */
1120 		if (mips_srs_max() > 1)
1121 			change_c0_srsmap (0xf << n*4, srs << n*4);
1122 	}
1123 
1124 	if (srs == 0) {
1125 		/*
1126 		 * If no shadow set is selected then use the default handler
1127 		 * that does normal register saving and a standard interrupt exit
1128 		 */
1129 
1130 		extern char except_vec_vi, except_vec_vi_lui;
1131 		extern char except_vec_vi_ori, except_vec_vi_end;
1132 #ifdef CONFIG_MIPS_MT_SMTC
1133 		/*
1134 		 * We need to provide the SMTC vectored interrupt handler
1135 		 * not only with the address of the handler, but with the
1136 		 * Status.IM bit to be masked before going there.
1137 		 */
1138 		extern char except_vec_vi_mori;
1139 		const int mori_offset = &except_vec_vi_mori - &except_vec_vi;
1140 #endif /* CONFIG_MIPS_MT_SMTC */
1141 		const int handler_len = &except_vec_vi_end - &except_vec_vi;
1142 		const int lui_offset = &except_vec_vi_lui - &except_vec_vi;
1143 		const int ori_offset = &except_vec_vi_ori - &except_vec_vi;
1144 
1145 		if (handler_len > VECTORSPACING) {
1146 			/*
1147 			 * Sigh... panicing won't help as the console
1148 			 * is probably not configured :(
1149 			 */
1150 			panic ("VECTORSPACING too small");
1151 		}
1152 
1153 		memcpy (b, &except_vec_vi, handler_len);
1154 #ifdef CONFIG_MIPS_MT_SMTC
1155 		if (n > 7)
1156 			printk("Vector index %d exceeds SMTC maximum\n", n);
1157 		w = (u32 *)(b + mori_offset);
1158 		*w = (*w & 0xffff0000) | (0x100 << n);
1159 #endif /* CONFIG_MIPS_MT_SMTC */
1160 		w = (u32 *)(b + lui_offset);
1161 		*w = (*w & 0xffff0000) | (((u32)handler >> 16) & 0xffff);
1162 		w = (u32 *)(b + ori_offset);
1163 		*w = (*w & 0xffff0000) | ((u32)handler & 0xffff);
1164 		flush_icache_range((unsigned long)b, (unsigned long)(b+handler_len));
1165 	}
1166 	else {
1167 		/*
1168 		 * In other cases jump directly to the interrupt handler
1169 		 *
1170 		 * It is the handlers responsibility to save registers if required
1171 		 * (eg hi/lo) and return from the exception using "eret"
1172 		 */
1173 		w = (u32 *)b;
1174 		*w++ = 0x08000000 | (((u32)handler >> 2) & 0x03fffff); /* j handler */
1175 		*w = 0;
1176 		flush_icache_range((unsigned long)b, (unsigned long)(b+8));
1177 	}
1178 
1179 	return (void *)old_handler;
1180 }
1181 
1182 void *set_vi_handler(int n, void *addr)
1183 {
1184 	return set_vi_srs_handler(n, addr, 0);
1185 }
1186 #endif
1187 
1188 /*
1189  * This is used by native signal handling
1190  */
1191 asmlinkage int (*save_fp_context)(struct sigcontext *sc);
1192 asmlinkage int (*restore_fp_context)(struct sigcontext *sc);
1193 
1194 extern asmlinkage int _save_fp_context(struct sigcontext *sc);
1195 extern asmlinkage int _restore_fp_context(struct sigcontext *sc);
1196 
1197 extern asmlinkage int fpu_emulator_save_context(struct sigcontext *sc);
1198 extern asmlinkage int fpu_emulator_restore_context(struct sigcontext *sc);
1199 
1200 #ifdef CONFIG_SMP
1201 static int smp_save_fp_context(struct sigcontext *sc)
1202 {
1203 	return cpu_has_fpu
1204 	       ? _save_fp_context(sc)
1205 	       : fpu_emulator_save_context(sc);
1206 }
1207 
1208 static int smp_restore_fp_context(struct sigcontext *sc)
1209 {
1210 	return cpu_has_fpu
1211 	       ? _restore_fp_context(sc)
1212 	       : fpu_emulator_restore_context(sc);
1213 }
1214 #endif
1215 
1216 static inline void signal_init(void)
1217 {
1218 #ifdef CONFIG_SMP
1219 	/* For now just do the cpu_has_fpu check when the functions are invoked */
1220 	save_fp_context = smp_save_fp_context;
1221 	restore_fp_context = smp_restore_fp_context;
1222 #else
1223 	if (cpu_has_fpu) {
1224 		save_fp_context = _save_fp_context;
1225 		restore_fp_context = _restore_fp_context;
1226 	} else {
1227 		save_fp_context = fpu_emulator_save_context;
1228 		restore_fp_context = fpu_emulator_restore_context;
1229 	}
1230 #endif
1231 }
1232 
1233 #ifdef CONFIG_MIPS32_COMPAT
1234 
1235 /*
1236  * This is used by 32-bit signal stuff on the 64-bit kernel
1237  */
1238 asmlinkage int (*save_fp_context32)(struct sigcontext32 *sc);
1239 asmlinkage int (*restore_fp_context32)(struct sigcontext32 *sc);
1240 
1241 extern asmlinkage int _save_fp_context32(struct sigcontext32 *sc);
1242 extern asmlinkage int _restore_fp_context32(struct sigcontext32 *sc);
1243 
1244 extern asmlinkage int fpu_emulator_save_context32(struct sigcontext32 *sc);
1245 extern asmlinkage int fpu_emulator_restore_context32(struct sigcontext32 *sc);
1246 
1247 static inline void signal32_init(void)
1248 {
1249 	if (cpu_has_fpu) {
1250 		save_fp_context32 = _save_fp_context32;
1251 		restore_fp_context32 = _restore_fp_context32;
1252 	} else {
1253 		save_fp_context32 = fpu_emulator_save_context32;
1254 		restore_fp_context32 = fpu_emulator_restore_context32;
1255 	}
1256 }
1257 #endif
1258 
1259 extern void cpu_cache_init(void);
1260 extern void tlb_init(void);
1261 extern void flush_tlb_handlers(void);
1262 
1263 void __init per_cpu_trap_init(void)
1264 {
1265 	unsigned int cpu = smp_processor_id();
1266 	unsigned int status_set = ST0_CU0;
1267 #ifdef CONFIG_MIPS_MT_SMTC
1268 	int secondaryTC = 0;
1269 	int bootTC = (cpu == 0);
1270 
1271 	/*
1272 	 * Only do per_cpu_trap_init() for first TC of Each VPE.
1273 	 * Note that this hack assumes that the SMTC init code
1274 	 * assigns TCs consecutively and in ascending order.
1275 	 */
1276 
1277 	if (((read_c0_tcbind() & TCBIND_CURTC) != 0) &&
1278 	    ((read_c0_tcbind() & TCBIND_CURVPE) == cpu_data[cpu - 1].vpe_id))
1279 		secondaryTC = 1;
1280 #endif /* CONFIG_MIPS_MT_SMTC */
1281 
1282 	/*
1283 	 * Disable coprocessors and select 32-bit or 64-bit addressing
1284 	 * and the 16/32 or 32/32 FPR register model.  Reset the BEV
1285 	 * flag that some firmware may have left set and the TS bit (for
1286 	 * IP27).  Set XX for ISA IV code to work.
1287 	 */
1288 #ifdef CONFIG_64BIT
1289 	status_set |= ST0_FR|ST0_KX|ST0_SX|ST0_UX;
1290 #endif
1291 	if (current_cpu_data.isa_level == MIPS_CPU_ISA_IV)
1292 		status_set |= ST0_XX;
1293 	change_c0_status(ST0_CU|ST0_MX|ST0_RE|ST0_FR|ST0_BEV|ST0_TS|ST0_KX|ST0_SX|ST0_UX,
1294 			 status_set);
1295 
1296 	if (cpu_has_dsp)
1297 		set_c0_status(ST0_MX);
1298 
1299 #ifdef CONFIG_CPU_MIPSR2
1300 	write_c0_hwrena (0x0000000f); /* Allow rdhwr to all registers */
1301 #endif
1302 
1303 #ifdef CONFIG_MIPS_MT_SMTC
1304 	if (!secondaryTC) {
1305 #endif /* CONFIG_MIPS_MT_SMTC */
1306 
1307 	/*
1308 	 * Interrupt handling.
1309 	 */
1310 	if (cpu_has_veic || cpu_has_vint) {
1311 		write_c0_ebase (ebase);
1312 		/* Setting vector spacing enables EI/VI mode  */
1313 		change_c0_intctl (0x3e0, VECTORSPACING);
1314 	}
1315 	if (cpu_has_divec) {
1316 		if (cpu_has_mipsmt) {
1317 			unsigned int vpflags = dvpe();
1318 			set_c0_cause(CAUSEF_IV);
1319 			evpe(vpflags);
1320 		} else
1321 			set_c0_cause(CAUSEF_IV);
1322 	}
1323 #ifdef CONFIG_MIPS_MT_SMTC
1324 	}
1325 #endif /* CONFIG_MIPS_MT_SMTC */
1326 
1327 	cpu_data[cpu].asid_cache = ASID_FIRST_VERSION;
1328 	TLBMISS_HANDLER_SETUP();
1329 
1330 	atomic_inc(&init_mm.mm_count);
1331 	current->active_mm = &init_mm;
1332 	BUG_ON(current->mm);
1333 	enter_lazy_tlb(&init_mm, current);
1334 
1335 #ifdef CONFIG_MIPS_MT_SMTC
1336 	if (bootTC) {
1337 #endif /* CONFIG_MIPS_MT_SMTC */
1338 		cpu_cache_init();
1339 		tlb_init();
1340 #ifdef CONFIG_MIPS_MT_SMTC
1341 	}
1342 #endif /* CONFIG_MIPS_MT_SMTC */
1343 }
1344 
1345 /* Install CPU exception handler */
1346 void __init set_handler (unsigned long offset, void *addr, unsigned long size)
1347 {
1348 	memcpy((void *)(ebase + offset), addr, size);
1349 	flush_icache_range(ebase + offset, ebase + offset + size);
1350 }
1351 
1352 /* Install uncached CPU exception handler */
1353 void __init set_uncached_handler (unsigned long offset, void *addr, unsigned long size)
1354 {
1355 #ifdef CONFIG_32BIT
1356 	unsigned long uncached_ebase = KSEG1ADDR(ebase);
1357 #endif
1358 #ifdef CONFIG_64BIT
1359 	unsigned long uncached_ebase = TO_UNCAC(ebase);
1360 #endif
1361 
1362 	memcpy((void *)(uncached_ebase + offset), addr, size);
1363 }
1364 
1365 void __init trap_init(void)
1366 {
1367 	extern char except_vec3_generic, except_vec3_r4000;
1368 	extern char except_vec4;
1369 	unsigned long i;
1370 
1371 	if (cpu_has_veic || cpu_has_vint)
1372 		ebase = (unsigned long) alloc_bootmem_low_pages (0x200 + VECTORSPACING*64);
1373 	else
1374 		ebase = CAC_BASE;
1375 
1376 #ifdef CONFIG_CPU_MIPSR2
1377 	mips_srs_init();
1378 #endif
1379 
1380 	per_cpu_trap_init();
1381 
1382 	/*
1383 	 * Copy the generic exception handlers to their final destination.
1384 	 * This will be overriden later as suitable for a particular
1385 	 * configuration.
1386 	 */
1387 	set_handler(0x180, &except_vec3_generic, 0x80);
1388 
1389 	/*
1390 	 * Setup default vectors
1391 	 */
1392 	for (i = 0; i <= 31; i++)
1393 		set_except_vector(i, handle_reserved);
1394 
1395 	/*
1396 	 * Copy the EJTAG debug exception vector handler code to it's final
1397 	 * destination.
1398 	 */
1399 	if (cpu_has_ejtag && board_ejtag_handler_setup)
1400 		board_ejtag_handler_setup ();
1401 
1402 	/*
1403 	 * Only some CPUs have the watch exceptions.
1404 	 */
1405 	if (cpu_has_watch)
1406 		set_except_vector(23, handle_watch);
1407 
1408 	/*
1409 	 * Initialise interrupt handlers
1410 	 */
1411 	if (cpu_has_veic || cpu_has_vint) {
1412 		int nvec = cpu_has_veic ? 64 : 8;
1413 		for (i = 0; i < nvec; i++)
1414 			set_vi_handler(i, NULL);
1415 	}
1416 	else if (cpu_has_divec)
1417 		set_handler(0x200, &except_vec4, 0x8);
1418 
1419 	/*
1420 	 * Some CPUs can enable/disable for cache parity detection, but does
1421 	 * it different ways.
1422 	 */
1423 	parity_protection_init();
1424 
1425 	/*
1426 	 * The Data Bus Errors / Instruction Bus Errors are signaled
1427 	 * by external hardware.  Therefore these two exceptions
1428 	 * may have board specific handlers.
1429 	 */
1430 	if (board_be_init)
1431 		board_be_init();
1432 
1433 	set_except_vector(0, handle_int);
1434 	set_except_vector(1, handle_tlbm);
1435 	set_except_vector(2, handle_tlbl);
1436 	set_except_vector(3, handle_tlbs);
1437 
1438 	set_except_vector(4, handle_adel);
1439 	set_except_vector(5, handle_ades);
1440 
1441 	set_except_vector(6, handle_ibe);
1442 	set_except_vector(7, handle_dbe);
1443 
1444 	set_except_vector(8, handle_sys);
1445 	set_except_vector(9, handle_bp);
1446 	set_except_vector(10, handle_ri);
1447 	set_except_vector(11, handle_cpu);
1448 	set_except_vector(12, handle_ov);
1449 	set_except_vector(13, handle_tr);
1450 
1451 	if (current_cpu_data.cputype == CPU_R6000 ||
1452 	    current_cpu_data.cputype == CPU_R6000A) {
1453 		/*
1454 		 * The R6000 is the only R-series CPU that features a machine
1455 		 * check exception (similar to the R4000 cache error) and
1456 		 * unaligned ldc1/sdc1 exception.  The handlers have not been
1457 		 * written yet.  Well, anyway there is no R6000 machine on the
1458 		 * current list of targets for Linux/MIPS.
1459 		 * (Duh, crap, there is someone with a triple R6k machine)
1460 		 */
1461 		//set_except_vector(14, handle_mc);
1462 		//set_except_vector(15, handle_ndc);
1463 	}
1464 
1465 
1466 	if (board_nmi_handler_setup)
1467 		board_nmi_handler_setup();
1468 
1469 	if (cpu_has_fpu && !cpu_has_nofpuex)
1470 		set_except_vector(15, handle_fpe);
1471 
1472 	set_except_vector(22, handle_mdmx);
1473 
1474 	if (cpu_has_mcheck)
1475 		set_except_vector(24, handle_mcheck);
1476 
1477 	if (cpu_has_mipsmt)
1478 		set_except_vector(25, handle_mt);
1479 
1480 	if (cpu_has_dsp)
1481 		set_except_vector(26, handle_dsp);
1482 
1483 	if (cpu_has_vce)
1484 		/* Special exception: R4[04]00 uses also the divec space. */
1485 		memcpy((void *)(CAC_BASE + 0x180), &except_vec3_r4000, 0x100);
1486 	else if (cpu_has_4kex)
1487 		memcpy((void *)(CAC_BASE + 0x180), &except_vec3_generic, 0x80);
1488 	else
1489 		memcpy((void *)(CAC_BASE + 0x080), &except_vec3_generic, 0x80);
1490 
1491 	signal_init();
1492 #ifdef CONFIG_MIPS32_COMPAT
1493 	signal32_init();
1494 #endif
1495 
1496 	flush_icache_range(ebase, ebase + 0x400);
1497 	flush_tlb_handlers();
1498 }
1499