xref: /linux/arch/mips/kernel/traps.c (revision 2b8232ce512105e28453f301d1510de8363bccd1)
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/bug.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/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/types.h>
43 #include <asm/stacktrace.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_ri_rdhwr_vivt(void);
57 extern asmlinkage void handle_ri_rdhwr(void);
58 extern asmlinkage void handle_cpu(void);
59 extern asmlinkage void handle_ov(void);
60 extern asmlinkage void handle_tr(void);
61 extern asmlinkage void handle_fpe(void);
62 extern asmlinkage void handle_mdmx(void);
63 extern asmlinkage void handle_watch(void);
64 extern asmlinkage void handle_mt(void);
65 extern asmlinkage void handle_dsp(void);
66 extern asmlinkage void handle_mcheck(void);
67 extern asmlinkage void handle_reserved(void);
68 
69 extern int fpu_emulator_cop1Handler(struct pt_regs *xcp,
70 	struct mips_fpu_struct *ctx, int has_fpu);
71 
72 void (*board_watchpoint_handler)(struct pt_regs *regs);
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 __user *sp = (unsigned long __user *)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 static void show_code(unsigned int __user *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 #ifdef CONFIG_CPU_HAS_SMARTMIPS
233 	printk("Acx    : %0*lx\n", field, regs->acx);
234 #endif
235 	printk("Hi    : %0*lx\n", field, regs->hi);
236 	printk("Lo    : %0*lx\n", field, regs->lo);
237 
238 	/*
239 	 * Saved cp0 registers
240 	 */
241 	printk("epc   : %0*lx ", field, regs->cp0_epc);
242 	print_symbol("%s ", regs->cp0_epc);
243 	printk("    %s\n", print_tainted());
244 	printk("ra    : %0*lx ", field, regs->regs[31]);
245 	print_symbol("%s\n", regs->regs[31]);
246 
247 	printk("Status: %08x    ", (uint32_t) regs->cp0_status);
248 
249 	if (current_cpu_data.isa_level == MIPS_CPU_ISA_I) {
250 		if (regs->cp0_status & ST0_KUO)
251 			printk("KUo ");
252 		if (regs->cp0_status & ST0_IEO)
253 			printk("IEo ");
254 		if (regs->cp0_status & ST0_KUP)
255 			printk("KUp ");
256 		if (regs->cp0_status & ST0_IEP)
257 			printk("IEp ");
258 		if (regs->cp0_status & ST0_KUC)
259 			printk("KUc ");
260 		if (regs->cp0_status & ST0_IEC)
261 			printk("IEc ");
262 	} else {
263 		if (regs->cp0_status & ST0_KX)
264 			printk("KX ");
265 		if (regs->cp0_status & ST0_SX)
266 			printk("SX ");
267 		if (regs->cp0_status & ST0_UX)
268 			printk("UX ");
269 		switch (regs->cp0_status & ST0_KSU) {
270 		case KSU_USER:
271 			printk("USER ");
272 			break;
273 		case KSU_SUPERVISOR:
274 			printk("SUPERVISOR ");
275 			break;
276 		case KSU_KERNEL:
277 			printk("KERNEL ");
278 			break;
279 		default:
280 			printk("BAD_MODE ");
281 			break;
282 		}
283 		if (regs->cp0_status & ST0_ERL)
284 			printk("ERL ");
285 		if (regs->cp0_status & ST0_EXL)
286 			printk("EXL ");
287 		if (regs->cp0_status & ST0_IE)
288 			printk("IE ");
289 	}
290 	printk("\n");
291 
292 	printk("Cause : %08x\n", cause);
293 
294 	cause = (cause & CAUSEF_EXCCODE) >> CAUSEB_EXCCODE;
295 	if (1 <= cause && cause <= 5)
296 		printk("BadVA : %0*lx\n", field, regs->cp0_badvaddr);
297 
298 	printk("PrId  : %08x (%s)\n", read_c0_prid(),
299 	       cpu_name_string());
300 }
301 
302 void show_registers(struct pt_regs *regs)
303 {
304 	show_regs(regs);
305 	print_modules();
306 	printk("Process %s (pid: %d, threadinfo=%p, task=%p)\n",
307 	        current->comm, current->pid, current_thread_info(), current);
308 	show_stacktrace(current, regs);
309 	show_code((unsigned int __user *) regs->cp0_epc);
310 	printk("\n");
311 }
312 
313 static DEFINE_SPINLOCK(die_lock);
314 
315 void __noreturn die(const char * str, struct pt_regs * regs)
316 {
317 	static int die_counter;
318 #ifdef CONFIG_MIPS_MT_SMTC
319 	unsigned long dvpret = dvpe();
320 #endif /* CONFIG_MIPS_MT_SMTC */
321 
322 	console_verbose();
323 	spin_lock_irq(&die_lock);
324 	bust_spinlocks(1);
325 #ifdef CONFIG_MIPS_MT_SMTC
326 	mips_mt_regdump(dvpret);
327 #endif /* CONFIG_MIPS_MT_SMTC */
328 	printk("%s[#%d]:\n", str, ++die_counter);
329 	show_registers(regs);
330 	add_taint(TAINT_DIE);
331 	spin_unlock_irq(&die_lock);
332 
333 	if (in_interrupt())
334 		panic("Fatal exception in interrupt");
335 
336 	if (panic_on_oops) {
337 		printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
338 		ssleep(5);
339 		panic("Fatal exception");
340 	}
341 
342 	do_exit(SIGSEGV);
343 }
344 
345 extern const struct exception_table_entry __start___dbe_table[];
346 extern const struct exception_table_entry __stop___dbe_table[];
347 
348 __asm__(
349 "	.section	__dbe_table, \"a\"\n"
350 "	.previous			\n");
351 
352 /* Given an address, look for it in the exception tables. */
353 static const struct exception_table_entry *search_dbe_tables(unsigned long addr)
354 {
355 	const struct exception_table_entry *e;
356 
357 	e = search_extable(__start___dbe_table, __stop___dbe_table - 1, addr);
358 	if (!e)
359 		e = search_module_dbetables(addr);
360 	return e;
361 }
362 
363 asmlinkage void do_be(struct pt_regs *regs)
364 {
365 	const int field = 2 * sizeof(unsigned long);
366 	const struct exception_table_entry *fixup = NULL;
367 	int data = regs->cp0_cause & 4;
368 	int action = MIPS_BE_FATAL;
369 
370 	/* XXX For now.  Fixme, this searches the wrong table ...  */
371 	if (data && !user_mode(regs))
372 		fixup = search_dbe_tables(exception_epc(regs));
373 
374 	if (fixup)
375 		action = MIPS_BE_FIXUP;
376 
377 	if (board_be_handler)
378 		action = board_be_handler(regs, fixup != NULL);
379 
380 	switch (action) {
381 	case MIPS_BE_DISCARD:
382 		return;
383 	case MIPS_BE_FIXUP:
384 		if (fixup) {
385 			regs->cp0_epc = fixup->nextinsn;
386 			return;
387 		}
388 		break;
389 	default:
390 		break;
391 	}
392 
393 	/*
394 	 * Assume it would be too dangerous to continue ...
395 	 */
396 	printk(KERN_ALERT "%s bus error, epc == %0*lx, ra == %0*lx\n",
397 	       data ? "Data" : "Instruction",
398 	       field, regs->cp0_epc, field, regs->regs[31]);
399 	die_if_kernel("Oops", regs);
400 	force_sig(SIGBUS, current);
401 }
402 
403 /*
404  * ll/sc emulation
405  */
406 
407 #define OPCODE 0xfc000000
408 #define BASE   0x03e00000
409 #define RT     0x001f0000
410 #define OFFSET 0x0000ffff
411 #define LL     0xc0000000
412 #define SC     0xe0000000
413 #define SPEC3  0x7c000000
414 #define RD     0x0000f800
415 #define FUNC   0x0000003f
416 #define RDHWR  0x0000003b
417 
418 /*
419  * The ll_bit is cleared by r*_switch.S
420  */
421 
422 unsigned long ll_bit;
423 
424 static struct task_struct *ll_task = NULL;
425 
426 static inline void simulate_ll(struct pt_regs *regs, unsigned int opcode)
427 {
428 	unsigned long value, __user *vaddr;
429 	long offset;
430 	int signal = 0;
431 
432 	/*
433 	 * analyse the ll instruction that just caused a ri exception
434 	 * and put the referenced address to addr.
435 	 */
436 
437 	/* sign extend offset */
438 	offset = opcode & OFFSET;
439 	offset <<= 16;
440 	offset >>= 16;
441 
442 	vaddr = (unsigned long __user *)
443 	        ((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
444 
445 	if ((unsigned long)vaddr & 3) {
446 		signal = SIGBUS;
447 		goto sig;
448 	}
449 	if (get_user(value, vaddr)) {
450 		signal = SIGSEGV;
451 		goto sig;
452 	}
453 
454 	preempt_disable();
455 
456 	if (ll_task == NULL || ll_task == current) {
457 		ll_bit = 1;
458 	} else {
459 		ll_bit = 0;
460 	}
461 	ll_task = current;
462 
463 	preempt_enable();
464 
465 	compute_return_epc(regs);
466 
467 	regs->regs[(opcode & RT) >> 16] = value;
468 
469 	return;
470 
471 sig:
472 	force_sig(signal, current);
473 }
474 
475 static inline void simulate_sc(struct pt_regs *regs, unsigned int opcode)
476 {
477 	unsigned long __user *vaddr;
478 	unsigned long reg;
479 	long offset;
480 	int signal = 0;
481 
482 	/*
483 	 * analyse the sc instruction that just caused a ri exception
484 	 * and put the referenced address to addr.
485 	 */
486 
487 	/* sign extend offset */
488 	offset = opcode & OFFSET;
489 	offset <<= 16;
490 	offset >>= 16;
491 
492 	vaddr = (unsigned long __user *)
493 	        ((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
494 	reg = (opcode & RT) >> 16;
495 
496 	if ((unsigned long)vaddr & 3) {
497 		signal = SIGBUS;
498 		goto sig;
499 	}
500 
501 	preempt_disable();
502 
503 	if (ll_bit == 0 || ll_task != current) {
504 		compute_return_epc(regs);
505 		regs->regs[reg] = 0;
506 		preempt_enable();
507 		return;
508 	}
509 
510 	preempt_enable();
511 
512 	if (put_user(regs->regs[reg], vaddr)) {
513 		signal = SIGSEGV;
514 		goto sig;
515 	}
516 
517 	compute_return_epc(regs);
518 	regs->regs[reg] = 1;
519 
520 	return;
521 
522 sig:
523 	force_sig(signal, current);
524 }
525 
526 /*
527  * ll uses the opcode of lwc0 and sc uses the opcode of swc0.  That is both
528  * opcodes are supposed to result in coprocessor unusable exceptions if
529  * executed on ll/sc-less processors.  That's the theory.  In practice a
530  * few processors such as NEC's VR4100 throw reserved instruction exceptions
531  * instead, so we're doing the emulation thing in both exception handlers.
532  */
533 static inline int simulate_llsc(struct pt_regs *regs)
534 {
535 	unsigned int opcode;
536 
537 	if (get_user(opcode, (unsigned int __user *) exception_epc(regs)))
538 		goto out_sigsegv;
539 
540 	if ((opcode & OPCODE) == LL) {
541 		simulate_ll(regs, opcode);
542 		return 0;
543 	}
544 	if ((opcode & OPCODE) == SC) {
545 		simulate_sc(regs, opcode);
546 		return 0;
547 	}
548 
549 	return -EFAULT;			/* Strange things going on ... */
550 
551 out_sigsegv:
552 	force_sig(SIGSEGV, current);
553 	return -EFAULT;
554 }
555 
556 /*
557  * Simulate trapping 'rdhwr' instructions to provide user accessible
558  * registers not implemented in hardware.  The only current use of this
559  * is the thread area pointer.
560  */
561 static inline int simulate_rdhwr(struct pt_regs *regs)
562 {
563 	struct thread_info *ti = task_thread_info(current);
564 	unsigned int opcode;
565 
566 	if (get_user(opcode, (unsigned int __user *) exception_epc(regs)))
567 		goto out_sigsegv;
568 
569 	if (unlikely(compute_return_epc(regs)))
570 		return -EFAULT;
571 
572 	if ((opcode & OPCODE) == SPEC3 && (opcode & FUNC) == RDHWR) {
573 		int rd = (opcode & RD) >> 11;
574 		int rt = (opcode & RT) >> 16;
575 		switch (rd) {
576 			case 29:
577 				regs->regs[rt] = ti->tp_value;
578 				return 0;
579 			default:
580 				return -EFAULT;
581 		}
582 	}
583 
584 	/* Not ours.  */
585 	return -EFAULT;
586 
587 out_sigsegv:
588 	force_sig(SIGSEGV, current);
589 	return -EFAULT;
590 }
591 
592 asmlinkage void do_ov(struct pt_regs *regs)
593 {
594 	siginfo_t info;
595 
596 	die_if_kernel("Integer overflow", regs);
597 
598 	info.si_code = FPE_INTOVF;
599 	info.si_signo = SIGFPE;
600 	info.si_errno = 0;
601 	info.si_addr = (void __user *) regs->cp0_epc;
602 	force_sig_info(SIGFPE, &info, current);
603 }
604 
605 /*
606  * XXX Delayed fp exceptions when doing a lazy ctx switch XXX
607  */
608 asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
609 {
610 	siginfo_t info;
611 
612 	die_if_kernel("FP exception in kernel code", regs);
613 
614 	if (fcr31 & FPU_CSR_UNI_X) {
615 		int sig;
616 
617 		/*
618 		 * Unimplemented operation exception.  If we've got the full
619 		 * software emulator on-board, let's use it...
620 		 *
621 		 * Force FPU to dump state into task/thread context.  We're
622 		 * moving a lot of data here for what is probably a single
623 		 * instruction, but the alternative is to pre-decode the FP
624 		 * register operands before invoking the emulator, which seems
625 		 * a bit extreme for what should be an infrequent event.
626 		 */
627 		/* Ensure 'resume' not overwrite saved fp context again. */
628 		lose_fpu(1);
629 
630 		/* Run the emulator */
631 		sig = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1);
632 
633 		/*
634 		 * We can't allow the emulated instruction to leave any of
635 		 * the cause bit set in $fcr31.
636 		 */
637 		current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
638 
639 		/* Restore the hardware register state */
640 		own_fpu(1);	/* Using the FPU again.  */
641 
642 		/* If something went wrong, signal */
643 		if (sig)
644 			force_sig(sig, current);
645 
646 		return;
647 	} else if (fcr31 & FPU_CSR_INV_X)
648 		info.si_code = FPE_FLTINV;
649 	else if (fcr31 & FPU_CSR_DIV_X)
650 		info.si_code = FPE_FLTDIV;
651 	else if (fcr31 & FPU_CSR_OVF_X)
652 		info.si_code = FPE_FLTOVF;
653 	else if (fcr31 & FPU_CSR_UDF_X)
654 		info.si_code = FPE_FLTUND;
655 	else if (fcr31 & FPU_CSR_INE_X)
656 		info.si_code = FPE_FLTRES;
657 	else
658 		info.si_code = __SI_FAULT;
659 	info.si_signo = SIGFPE;
660 	info.si_errno = 0;
661 	info.si_addr = (void __user *) regs->cp0_epc;
662 	force_sig_info(SIGFPE, &info, current);
663 }
664 
665 asmlinkage void do_bp(struct pt_regs *regs)
666 {
667 	unsigned int opcode, bcode;
668 	siginfo_t info;
669 
670 	if (__get_user(opcode, (unsigned int __user *) exception_epc(regs)))
671 		goto out_sigsegv;
672 
673 	/*
674 	 * There is the ancient bug in the MIPS assemblers that the break
675 	 * code starts left to bit 16 instead to bit 6 in the opcode.
676 	 * Gas is bug-compatible, but not always, grrr...
677 	 * We handle both cases with a simple heuristics.  --macro
678 	 */
679 	bcode = ((opcode >> 6) & ((1 << 20) - 1));
680 	if (bcode < (1 << 10))
681 		bcode <<= 10;
682 
683 	/*
684 	 * (A short test says that IRIX 5.3 sends SIGTRAP for all break
685 	 * insns, even for break codes that indicate arithmetic failures.
686 	 * Weird ...)
687 	 * But should we continue the brokenness???  --macro
688 	 */
689 	switch (bcode) {
690 	case BRK_OVERFLOW << 10:
691 	case BRK_DIVZERO << 10:
692 		die_if_kernel("Break instruction in kernel code", regs);
693 		if (bcode == (BRK_DIVZERO << 10))
694 			info.si_code = FPE_INTDIV;
695 		else
696 			info.si_code = FPE_INTOVF;
697 		info.si_signo = SIGFPE;
698 		info.si_errno = 0;
699 		info.si_addr = (void __user *) regs->cp0_epc;
700 		force_sig_info(SIGFPE, &info, current);
701 		break;
702 	case BRK_BUG:
703 		die("Kernel bug detected", regs);
704 		break;
705 	default:
706 		die_if_kernel("Break instruction in kernel code", regs);
707 		force_sig(SIGTRAP, current);
708 	}
709 	return;
710 
711 out_sigsegv:
712 	force_sig(SIGSEGV, current);
713 }
714 
715 asmlinkage void do_tr(struct pt_regs *regs)
716 {
717 	unsigned int opcode, tcode = 0;
718 	siginfo_t info;
719 
720 	if (__get_user(opcode, (unsigned int __user *) exception_epc(regs)))
721 		goto out_sigsegv;
722 
723 	/* Immediate versions don't provide a code.  */
724 	if (!(opcode & OPCODE))
725 		tcode = ((opcode >> 6) & ((1 << 10) - 1));
726 
727 	/*
728 	 * (A short test says that IRIX 5.3 sends SIGTRAP for all trap
729 	 * insns, even for trap codes that indicate arithmetic failures.
730 	 * Weird ...)
731 	 * But should we continue the brokenness???  --macro
732 	 */
733 	switch (tcode) {
734 	case BRK_OVERFLOW:
735 	case BRK_DIVZERO:
736 		die_if_kernel("Trap instruction in kernel code", regs);
737 		if (tcode == BRK_DIVZERO)
738 			info.si_code = FPE_INTDIV;
739 		else
740 			info.si_code = FPE_INTOVF;
741 		info.si_signo = SIGFPE;
742 		info.si_errno = 0;
743 		info.si_addr = (void __user *) regs->cp0_epc;
744 		force_sig_info(SIGFPE, &info, current);
745 		break;
746 	case BRK_BUG:
747 		die("Kernel bug detected", regs);
748 		break;
749 	default:
750 		die_if_kernel("Trap instruction in kernel code", regs);
751 		force_sig(SIGTRAP, current);
752 	}
753 	return;
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 /*
774  * MIPS MT processors may have fewer FPU contexts than CPU threads. If we've
775  * emulated more than some threshold number of instructions, force migration to
776  * a "CPU" that has FP support.
777  */
778 static void mt_ase_fp_affinity(void)
779 {
780 #ifdef CONFIG_MIPS_MT_FPAFF
781 	if (mt_fpemul_threshold > 0 &&
782 	     ((current->thread.emulated_fp++ > mt_fpemul_threshold))) {
783 		/*
784 		 * If there's no FPU present, or if the application has already
785 		 * restricted the allowed set to exclude any CPUs with FPUs,
786 		 * we'll skip the procedure.
787 		 */
788 		if (cpus_intersects(current->cpus_allowed, mt_fpu_cpumask)) {
789 			cpumask_t tmask;
790 
791 			cpus_and(tmask, current->thread.user_cpus_allowed,
792 			         mt_fpu_cpumask);
793 			set_cpus_allowed(current, tmask);
794 			set_thread_flag(TIF_FPUBOUND);
795 		}
796 	}
797 #endif /* CONFIG_MIPS_MT_FPAFF */
798 }
799 
800 asmlinkage void do_cpu(struct pt_regs *regs)
801 {
802 	unsigned int cpid;
803 
804 	die_if_kernel("do_cpu invoked from kernel context!", regs);
805 
806 	cpid = (regs->cp0_cause >> CAUSEB_CE) & 3;
807 
808 	switch (cpid) {
809 	case 0:
810 		if (!cpu_has_llsc)
811 			if (!simulate_llsc(regs))
812 				return;
813 
814 		if (!simulate_rdhwr(regs))
815 			return;
816 
817 		break;
818 
819 	case 1:
820 		if (used_math())	/* Using the FPU again.  */
821 			own_fpu(1);
822 		else {			/* First time FPU user.  */
823 			init_fpu();
824 			set_used_math();
825 		}
826 
827 		if (!raw_cpu_has_fpu) {
828 			int sig;
829 			sig = fpu_emulator_cop1Handler(regs,
830 						&current->thread.fpu, 0);
831 			if (sig)
832 				force_sig(sig, current);
833 			else
834 				mt_ase_fp_affinity();
835 		}
836 
837 		return;
838 
839 	case 2:
840 	case 3:
841 		break;
842 	}
843 
844 	force_sig(SIGILL, current);
845 }
846 
847 asmlinkage void do_mdmx(struct pt_regs *regs)
848 {
849 	force_sig(SIGILL, current);
850 }
851 
852 asmlinkage void do_watch(struct pt_regs *regs)
853 {
854 	if (board_watchpoint_handler) {
855 		(*board_watchpoint_handler)(regs);
856 		return;
857 	}
858 
859 	/*
860 	 * We use the watch exception where available to detect stack
861 	 * overflows.
862 	 */
863 	dump_tlb_all();
864 	show_regs(regs);
865 	panic("Caught WATCH exception - probably caused by stack overflow.");
866 }
867 
868 asmlinkage void do_mcheck(struct pt_regs *regs)
869 {
870 	const int field = 2 * sizeof(unsigned long);
871 	int multi_match = regs->cp0_status & ST0_TS;
872 
873 	show_regs(regs);
874 
875 	if (multi_match) {
876 		printk("Index   : %0x\n", read_c0_index());
877 		printk("Pagemask: %0x\n", read_c0_pagemask());
878 		printk("EntryHi : %0*lx\n", field, read_c0_entryhi());
879 		printk("EntryLo0: %0*lx\n", field, read_c0_entrylo0());
880 		printk("EntryLo1: %0*lx\n", field, read_c0_entrylo1());
881 		printk("\n");
882 		dump_tlb_all();
883 	}
884 
885 	show_code((unsigned int __user *) regs->cp0_epc);
886 
887 	/*
888 	 * Some chips may have other causes of machine check (e.g. SB1
889 	 * graduation timer)
890 	 */
891 	panic("Caught Machine Check exception - %scaused by multiple "
892 	      "matching entries in the TLB.",
893 	      (multi_match) ? "" : "not ");
894 }
895 
896 asmlinkage void do_mt(struct pt_regs *regs)
897 {
898 	int subcode;
899 
900 	subcode = (read_vpe_c0_vpecontrol() & VPECONTROL_EXCPT)
901 			>> VPECONTROL_EXCPT_SHIFT;
902 	switch (subcode) {
903 	case 0:
904 		printk(KERN_DEBUG "Thread Underflow\n");
905 		break;
906 	case 1:
907 		printk(KERN_DEBUG "Thread Overflow\n");
908 		break;
909 	case 2:
910 		printk(KERN_DEBUG "Invalid YIELD Qualifier\n");
911 		break;
912 	case 3:
913 		printk(KERN_DEBUG "Gating Storage Exception\n");
914 		break;
915 	case 4:
916 		printk(KERN_DEBUG "YIELD Scheduler Exception\n");
917 		break;
918 	case 5:
919 		printk(KERN_DEBUG "Gating Storage Schedulier Exception\n");
920 		break;
921 	default:
922 		printk(KERN_DEBUG "*** UNKNOWN THREAD EXCEPTION %d ***\n",
923 			subcode);
924 		break;
925 	}
926 	die_if_kernel("MIPS MT Thread exception in kernel", regs);
927 
928 	force_sig(SIGILL, current);
929 }
930 
931 
932 asmlinkage void do_dsp(struct pt_regs *regs)
933 {
934 	if (cpu_has_dsp)
935 		panic("Unexpected DSP exception\n");
936 
937 	force_sig(SIGILL, current);
938 }
939 
940 asmlinkage void do_reserved(struct pt_regs *regs)
941 {
942 	/*
943 	 * Game over - no way to handle this if it ever occurs.  Most probably
944 	 * caused by a new unknown cpu type or after another deadly
945 	 * hard/software error.
946 	 */
947 	show_regs(regs);
948 	panic("Caught reserved exception %ld - should not happen.",
949 	      (regs->cp0_cause & 0x7f) >> 2);
950 }
951 
952 /*
953  * Some MIPS CPUs can enable/disable for cache parity detection, but do
954  * it different ways.
955  */
956 static inline void parity_protection_init(void)
957 {
958 	switch (current_cpu_type()) {
959 	case CPU_24K:
960 	case CPU_34K:
961 	case CPU_5KC:
962 		write_c0_ecc(0x80000000);
963 		back_to_back_c0_hazard();
964 		/* Set the PE bit (bit 31) in the c0_errctl register. */
965 		printk(KERN_INFO "Cache parity protection %sabled\n",
966 		       (read_c0_ecc() & 0x80000000) ? "en" : "dis");
967 		break;
968 	case CPU_20KC:
969 	case CPU_25KF:
970 		/* Clear the DE bit (bit 16) in the c0_status register. */
971 		printk(KERN_INFO "Enable cache parity protection for "
972 		       "MIPS 20KC/25KF CPUs.\n");
973 		clear_c0_status(ST0_DE);
974 		break;
975 	default:
976 		break;
977 	}
978 }
979 
980 asmlinkage void cache_parity_error(void)
981 {
982 	const int field = 2 * sizeof(unsigned long);
983 	unsigned int reg_val;
984 
985 	/* For the moment, report the problem and hang. */
986 	printk("Cache error exception:\n");
987 	printk("cp0_errorepc == %0*lx\n", field, read_c0_errorepc());
988 	reg_val = read_c0_cacheerr();
989 	printk("c0_cacheerr == %08x\n", reg_val);
990 
991 	printk("Decoded c0_cacheerr: %s cache fault in %s reference.\n",
992 	       reg_val & (1<<30) ? "secondary" : "primary",
993 	       reg_val & (1<<31) ? "data" : "insn");
994 	printk("Error bits: %s%s%s%s%s%s%s\n",
995 	       reg_val & (1<<29) ? "ED " : "",
996 	       reg_val & (1<<28) ? "ET " : "",
997 	       reg_val & (1<<26) ? "EE " : "",
998 	       reg_val & (1<<25) ? "EB " : "",
999 	       reg_val & (1<<24) ? "EI " : "",
1000 	       reg_val & (1<<23) ? "E1 " : "",
1001 	       reg_val & (1<<22) ? "E0 " : "");
1002 	printk("IDX: 0x%08x\n", reg_val & ((1<<22)-1));
1003 
1004 #if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
1005 	if (reg_val & (1<<22))
1006 		printk("DErrAddr0: 0x%0*lx\n", field, read_c0_derraddr0());
1007 
1008 	if (reg_val & (1<<23))
1009 		printk("DErrAddr1: 0x%0*lx\n", field, read_c0_derraddr1());
1010 #endif
1011 
1012 	panic("Can't handle the cache error!");
1013 }
1014 
1015 /*
1016  * SDBBP EJTAG debug exception handler.
1017  * We skip the instruction and return to the next instruction.
1018  */
1019 void ejtag_exception_handler(struct pt_regs *regs)
1020 {
1021 	const int field = 2 * sizeof(unsigned long);
1022 	unsigned long depc, old_epc;
1023 	unsigned int debug;
1024 
1025 	printk(KERN_DEBUG "SDBBP EJTAG debug exception - not handled yet, just ignored!\n");
1026 	depc = read_c0_depc();
1027 	debug = read_c0_debug();
1028 	printk(KERN_DEBUG "c0_depc = %0*lx, DEBUG = %08x\n", field, depc, debug);
1029 	if (debug & 0x80000000) {
1030 		/*
1031 		 * In branch delay slot.
1032 		 * We cheat a little bit here and use EPC to calculate the
1033 		 * debug return address (DEPC). EPC is restored after the
1034 		 * calculation.
1035 		 */
1036 		old_epc = regs->cp0_epc;
1037 		regs->cp0_epc = depc;
1038 		__compute_return_epc(regs);
1039 		depc = regs->cp0_epc;
1040 		regs->cp0_epc = old_epc;
1041 	} else
1042 		depc += 4;
1043 	write_c0_depc(depc);
1044 
1045 #if 0
1046 	printk(KERN_DEBUG "\n\n----- Enable EJTAG single stepping ----\n\n");
1047 	write_c0_debug(debug | 0x100);
1048 #endif
1049 }
1050 
1051 /*
1052  * NMI exception handler.
1053  */
1054 NORET_TYPE void ATTRIB_NORET nmi_exception_handler(struct pt_regs *regs)
1055 {
1056 	bust_spinlocks(1);
1057 	printk("NMI taken!!!!\n");
1058 	die("NMI", regs);
1059 }
1060 
1061 #define VECTORSPACING 0x100	/* for EI/VI mode */
1062 
1063 unsigned long ebase;
1064 unsigned long exception_handlers[32];
1065 unsigned long vi_handlers[64];
1066 
1067 /*
1068  * As a side effect of the way this is implemented we're limited
1069  * to interrupt handlers in the address range from
1070  * KSEG0 <= x < KSEG0 + 256mb on the Nevada.  Oh well ...
1071  */
1072 void *set_except_vector(int n, void *addr)
1073 {
1074 	unsigned long handler = (unsigned long) addr;
1075 	unsigned long old_handler = exception_handlers[n];
1076 
1077 	exception_handlers[n] = handler;
1078 	if (n == 0 && cpu_has_divec) {
1079 		*(u32 *)(ebase + 0x200) = 0x08000000 |
1080 					  (0x03ffffff & (handler >> 2));
1081 		flush_icache_range(ebase + 0x200, ebase + 0x204);
1082 	}
1083 	return (void *)old_handler;
1084 }
1085 
1086 #ifdef CONFIG_CPU_MIPSR2_SRS
1087 /*
1088  * MIPSR2 shadow register set allocation
1089  * FIXME: SMP...
1090  */
1091 
1092 static struct shadow_registers {
1093 	/*
1094 	 * Number of shadow register sets supported
1095 	 */
1096 	unsigned long sr_supported;
1097 	/*
1098 	 * Bitmap of allocated shadow registers
1099 	 */
1100 	unsigned long sr_allocated;
1101 } shadow_registers;
1102 
1103 static void mips_srs_init(void)
1104 {
1105 	shadow_registers.sr_supported = ((read_c0_srsctl() >> 26) & 0x0f) + 1;
1106 	printk(KERN_INFO "%ld MIPSR2 register sets available\n",
1107 	       shadow_registers.sr_supported);
1108 	shadow_registers.sr_allocated = 1;	/* Set 0 used by kernel */
1109 }
1110 
1111 int mips_srs_max(void)
1112 {
1113 	return shadow_registers.sr_supported;
1114 }
1115 
1116 int mips_srs_alloc(void)
1117 {
1118 	struct shadow_registers *sr = &shadow_registers;
1119 	int set;
1120 
1121 again:
1122 	set = find_first_zero_bit(&sr->sr_allocated, sr->sr_supported);
1123 	if (set >= sr->sr_supported)
1124 		return -1;
1125 
1126 	if (test_and_set_bit(set, &sr->sr_allocated))
1127 		goto again;
1128 
1129 	return set;
1130 }
1131 
1132 void mips_srs_free(int set)
1133 {
1134 	struct shadow_registers *sr = &shadow_registers;
1135 
1136 	clear_bit(set, &sr->sr_allocated);
1137 }
1138 
1139 static asmlinkage void do_default_vi(void)
1140 {
1141 	show_regs(get_irq_regs());
1142 	panic("Caught unexpected vectored interrupt.");
1143 }
1144 
1145 static void *set_vi_srs_handler(int n, vi_handler_t addr, int srs)
1146 {
1147 	unsigned long handler;
1148 	unsigned long old_handler = vi_handlers[n];
1149 	u32 *w;
1150 	unsigned char *b;
1151 
1152 	if (!cpu_has_veic && !cpu_has_vint)
1153 		BUG();
1154 
1155 	if (addr == NULL) {
1156 		handler = (unsigned long) do_default_vi;
1157 		srs = 0;
1158 	} else
1159 		handler = (unsigned long) addr;
1160 	vi_handlers[n] = (unsigned long) addr;
1161 
1162 	b = (unsigned char *)(ebase + 0x200 + n*VECTORSPACING);
1163 
1164 	if (srs >= mips_srs_max())
1165 		panic("Shadow register set %d not supported", srs);
1166 
1167 	if (cpu_has_veic) {
1168 		if (board_bind_eic_interrupt)
1169 			board_bind_eic_interrupt(n, srs);
1170 	} else if (cpu_has_vint) {
1171 		/* SRSMap is only defined if shadow sets are implemented */
1172 		if (mips_srs_max() > 1)
1173 			change_c0_srsmap(0xf << n*4, srs << n*4);
1174 	}
1175 
1176 	if (srs == 0) {
1177 		/*
1178 		 * If no shadow set is selected then use the default handler
1179 		 * that does normal register saving and a standard interrupt exit
1180 		 */
1181 
1182 		extern char except_vec_vi, except_vec_vi_lui;
1183 		extern char except_vec_vi_ori, except_vec_vi_end;
1184 #ifdef CONFIG_MIPS_MT_SMTC
1185 		/*
1186 		 * We need to provide the SMTC vectored interrupt handler
1187 		 * not only with the address of the handler, but with the
1188 		 * Status.IM bit to be masked before going there.
1189 		 */
1190 		extern char except_vec_vi_mori;
1191 		const int mori_offset = &except_vec_vi_mori - &except_vec_vi;
1192 #endif /* CONFIG_MIPS_MT_SMTC */
1193 		const int handler_len = &except_vec_vi_end - &except_vec_vi;
1194 		const int lui_offset = &except_vec_vi_lui - &except_vec_vi;
1195 		const int ori_offset = &except_vec_vi_ori - &except_vec_vi;
1196 
1197 		if (handler_len > VECTORSPACING) {
1198 			/*
1199 			 * Sigh... panicing won't help as the console
1200 			 * is probably not configured :(
1201 			 */
1202 			panic("VECTORSPACING too small");
1203 		}
1204 
1205 		memcpy(b, &except_vec_vi, handler_len);
1206 #ifdef CONFIG_MIPS_MT_SMTC
1207 		BUG_ON(n > 7);	/* Vector index %d exceeds SMTC maximum. */
1208 
1209 		w = (u32 *)(b + mori_offset);
1210 		*w = (*w & 0xffff0000) | (0x100 << n);
1211 #endif /* CONFIG_MIPS_MT_SMTC */
1212 		w = (u32 *)(b + lui_offset);
1213 		*w = (*w & 0xffff0000) | (((u32)handler >> 16) & 0xffff);
1214 		w = (u32 *)(b + ori_offset);
1215 		*w = (*w & 0xffff0000) | ((u32)handler & 0xffff);
1216 		flush_icache_range((unsigned long)b, (unsigned long)(b+handler_len));
1217 	}
1218 	else {
1219 		/*
1220 		 * In other cases jump directly to the interrupt handler
1221 		 *
1222 		 * It is the handlers responsibility to save registers if required
1223 		 * (eg hi/lo) and return from the exception using "eret"
1224 		 */
1225 		w = (u32 *)b;
1226 		*w++ = 0x08000000 | (((u32)handler >> 2) & 0x03fffff); /* j handler */
1227 		*w = 0;
1228 		flush_icache_range((unsigned long)b, (unsigned long)(b+8));
1229 	}
1230 
1231 	return (void *)old_handler;
1232 }
1233 
1234 void *set_vi_handler(int n, vi_handler_t addr)
1235 {
1236 	return set_vi_srs_handler(n, addr, 0);
1237 }
1238 
1239 #else
1240 
1241 static inline void mips_srs_init(void)
1242 {
1243 }
1244 
1245 #endif /* CONFIG_CPU_MIPSR2_SRS */
1246 
1247 /*
1248  * This is used by native signal handling
1249  */
1250 asmlinkage int (*save_fp_context)(struct sigcontext __user *sc);
1251 asmlinkage int (*restore_fp_context)(struct sigcontext __user *sc);
1252 
1253 extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
1254 extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
1255 
1256 extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc);
1257 extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc);
1258 
1259 #ifdef CONFIG_SMP
1260 static int smp_save_fp_context(struct sigcontext __user *sc)
1261 {
1262 	return raw_cpu_has_fpu
1263 	       ? _save_fp_context(sc)
1264 	       : fpu_emulator_save_context(sc);
1265 }
1266 
1267 static int smp_restore_fp_context(struct sigcontext __user *sc)
1268 {
1269 	return raw_cpu_has_fpu
1270 	       ? _restore_fp_context(sc)
1271 	       : fpu_emulator_restore_context(sc);
1272 }
1273 #endif
1274 
1275 static inline void signal_init(void)
1276 {
1277 #ifdef CONFIG_SMP
1278 	/* For now just do the cpu_has_fpu check when the functions are invoked */
1279 	save_fp_context = smp_save_fp_context;
1280 	restore_fp_context = smp_restore_fp_context;
1281 #else
1282 	if (cpu_has_fpu) {
1283 		save_fp_context = _save_fp_context;
1284 		restore_fp_context = _restore_fp_context;
1285 	} else {
1286 		save_fp_context = fpu_emulator_save_context;
1287 		restore_fp_context = fpu_emulator_restore_context;
1288 	}
1289 #endif
1290 }
1291 
1292 #ifdef CONFIG_MIPS32_COMPAT
1293 
1294 /*
1295  * This is used by 32-bit signal stuff on the 64-bit kernel
1296  */
1297 asmlinkage int (*save_fp_context32)(struct sigcontext32 __user *sc);
1298 asmlinkage int (*restore_fp_context32)(struct sigcontext32 __user *sc);
1299 
1300 extern asmlinkage int _save_fp_context32(struct sigcontext32 __user *sc);
1301 extern asmlinkage int _restore_fp_context32(struct sigcontext32 __user *sc);
1302 
1303 extern asmlinkage int fpu_emulator_save_context32(struct sigcontext32 __user *sc);
1304 extern asmlinkage int fpu_emulator_restore_context32(struct sigcontext32 __user *sc);
1305 
1306 static inline void signal32_init(void)
1307 {
1308 	if (cpu_has_fpu) {
1309 		save_fp_context32 = _save_fp_context32;
1310 		restore_fp_context32 = _restore_fp_context32;
1311 	} else {
1312 		save_fp_context32 = fpu_emulator_save_context32;
1313 		restore_fp_context32 = fpu_emulator_restore_context32;
1314 	}
1315 }
1316 #endif
1317 
1318 extern void cpu_cache_init(void);
1319 extern void tlb_init(void);
1320 extern void flush_tlb_handlers(void);
1321 
1322 void __init per_cpu_trap_init(void)
1323 {
1324 	unsigned int cpu = smp_processor_id();
1325 	unsigned int status_set = ST0_CU0;
1326 #ifdef CONFIG_MIPS_MT_SMTC
1327 	int secondaryTC = 0;
1328 	int bootTC = (cpu == 0);
1329 
1330 	/*
1331 	 * Only do per_cpu_trap_init() for first TC of Each VPE.
1332 	 * Note that this hack assumes that the SMTC init code
1333 	 * assigns TCs consecutively and in ascending order.
1334 	 */
1335 
1336 	if (((read_c0_tcbind() & TCBIND_CURTC) != 0) &&
1337 	    ((read_c0_tcbind() & TCBIND_CURVPE) == cpu_data[cpu - 1].vpe_id))
1338 		secondaryTC = 1;
1339 #endif /* CONFIG_MIPS_MT_SMTC */
1340 
1341 	/*
1342 	 * Disable coprocessors and select 32-bit or 64-bit addressing
1343 	 * and the 16/32 or 32/32 FPR register model.  Reset the BEV
1344 	 * flag that some firmware may have left set and the TS bit (for
1345 	 * IP27).  Set XX for ISA IV code to work.
1346 	 */
1347 #ifdef CONFIG_64BIT
1348 	status_set |= ST0_FR|ST0_KX|ST0_SX|ST0_UX;
1349 #endif
1350 	if (current_cpu_data.isa_level == MIPS_CPU_ISA_IV)
1351 		status_set |= ST0_XX;
1352 	change_c0_status(ST0_CU|ST0_MX|ST0_RE|ST0_FR|ST0_BEV|ST0_TS|ST0_KX|ST0_SX|ST0_UX,
1353 			 status_set);
1354 
1355 	if (cpu_has_dsp)
1356 		set_c0_status(ST0_MX);
1357 
1358 #ifdef CONFIG_CPU_MIPSR2
1359 	if (cpu_has_mips_r2) {
1360 		unsigned int enable = 0x0000000f;
1361 
1362 		if (cpu_has_userlocal)
1363 			enable |= (1 << 29);
1364 
1365 		write_c0_hwrena(enable);
1366 	}
1367 #endif
1368 
1369 #ifdef CONFIG_MIPS_MT_SMTC
1370 	if (!secondaryTC) {
1371 #endif /* CONFIG_MIPS_MT_SMTC */
1372 
1373 	if (cpu_has_veic || cpu_has_vint) {
1374 		write_c0_ebase(ebase);
1375 		/* Setting vector spacing enables EI/VI mode  */
1376 		change_c0_intctl(0x3e0, VECTORSPACING);
1377 	}
1378 	if (cpu_has_divec) {
1379 		if (cpu_has_mipsmt) {
1380 			unsigned int vpflags = dvpe();
1381 			set_c0_cause(CAUSEF_IV);
1382 			evpe(vpflags);
1383 		} else
1384 			set_c0_cause(CAUSEF_IV);
1385 	}
1386 
1387 	/*
1388 	 * Before R2 both interrupt numbers were fixed to 7, so on R2 only:
1389 	 *
1390 	 *  o read IntCtl.IPTI to determine the timer interrupt
1391 	 *  o read IntCtl.IPPCI to determine the performance counter interrupt
1392 	 */
1393 	if (cpu_has_mips_r2) {
1394 		cp0_compare_irq = (read_c0_intctl() >> 29) & 7;
1395 		cp0_perfcount_irq = (read_c0_intctl() >> 26) & 7;
1396 		if (cp0_perfcount_irq == cp0_compare_irq)
1397 			cp0_perfcount_irq = -1;
1398 	} else {
1399 		cp0_compare_irq = CP0_LEGACY_COMPARE_IRQ;
1400 		cp0_perfcount_irq = -1;
1401 	}
1402 
1403 #ifdef CONFIG_MIPS_MT_SMTC
1404 	}
1405 #endif /* CONFIG_MIPS_MT_SMTC */
1406 
1407 	cpu_data[cpu].asid_cache = ASID_FIRST_VERSION;
1408 	TLBMISS_HANDLER_SETUP();
1409 
1410 	atomic_inc(&init_mm.mm_count);
1411 	current->active_mm = &init_mm;
1412 	BUG_ON(current->mm);
1413 	enter_lazy_tlb(&init_mm, current);
1414 
1415 #ifdef CONFIG_MIPS_MT_SMTC
1416 	if (bootTC) {
1417 #endif /* CONFIG_MIPS_MT_SMTC */
1418 		cpu_cache_init();
1419 		tlb_init();
1420 #ifdef CONFIG_MIPS_MT_SMTC
1421 	} else if (!secondaryTC) {
1422 		/*
1423 		 * First TC in non-boot VPE must do subset of tlb_init()
1424 		 * for MMU countrol registers.
1425 		 */
1426 		write_c0_pagemask(PM_DEFAULT_MASK);
1427 		write_c0_wired(0);
1428 	}
1429 #endif /* CONFIG_MIPS_MT_SMTC */
1430 }
1431 
1432 /* Install CPU exception handler */
1433 void __init set_handler(unsigned long offset, void *addr, unsigned long size)
1434 {
1435 	memcpy((void *)(ebase + offset), addr, size);
1436 	flush_icache_range(ebase + offset, ebase + offset + size);
1437 }
1438 
1439 static char panic_null_cerr[] __initdata =
1440 	"Trying to set NULL cache error exception handler";
1441 
1442 /* Install uncached CPU exception handler */
1443 void __init set_uncached_handler(unsigned long offset, void *addr, unsigned long size)
1444 {
1445 #ifdef CONFIG_32BIT
1446 	unsigned long uncached_ebase = KSEG1ADDR(ebase);
1447 #endif
1448 #ifdef CONFIG_64BIT
1449 	unsigned long uncached_ebase = TO_UNCAC(ebase);
1450 #endif
1451 
1452 	if (!addr)
1453 		panic(panic_null_cerr);
1454 
1455 	memcpy((void *)(uncached_ebase + offset), addr, size);
1456 }
1457 
1458 static int __initdata rdhwr_noopt;
1459 static int __init set_rdhwr_noopt(char *str)
1460 {
1461 	rdhwr_noopt = 1;
1462 	return 1;
1463 }
1464 
1465 __setup("rdhwr_noopt", set_rdhwr_noopt);
1466 
1467 void __init trap_init(void)
1468 {
1469 	extern char except_vec3_generic, except_vec3_r4000;
1470 	extern char except_vec4;
1471 	unsigned long i;
1472 
1473 	if (cpu_has_veic || cpu_has_vint)
1474 		ebase = (unsigned long) alloc_bootmem_low_pages(0x200 + VECTORSPACING*64);
1475 	else
1476 		ebase = CAC_BASE;
1477 
1478 	mips_srs_init();
1479 
1480 	per_cpu_trap_init();
1481 
1482 	/*
1483 	 * Copy the generic exception handlers to their final destination.
1484 	 * This will be overriden later as suitable for a particular
1485 	 * configuration.
1486 	 */
1487 	set_handler(0x180, &except_vec3_generic, 0x80);
1488 
1489 	/*
1490 	 * Setup default vectors
1491 	 */
1492 	for (i = 0; i <= 31; i++)
1493 		set_except_vector(i, handle_reserved);
1494 
1495 	/*
1496 	 * Copy the EJTAG debug exception vector handler code to it's final
1497 	 * destination.
1498 	 */
1499 	if (cpu_has_ejtag && board_ejtag_handler_setup)
1500 		board_ejtag_handler_setup();
1501 
1502 	/*
1503 	 * Only some CPUs have the watch exceptions.
1504 	 */
1505 	if (cpu_has_watch)
1506 		set_except_vector(23, handle_watch);
1507 
1508 	/*
1509 	 * Initialise interrupt handlers
1510 	 */
1511 	if (cpu_has_veic || cpu_has_vint) {
1512 		int nvec = cpu_has_veic ? 64 : 8;
1513 		for (i = 0; i < nvec; i++)
1514 			set_vi_handler(i, NULL);
1515 	}
1516 	else if (cpu_has_divec)
1517 		set_handler(0x200, &except_vec4, 0x8);
1518 
1519 	/*
1520 	 * Some CPUs can enable/disable for cache parity detection, but does
1521 	 * it different ways.
1522 	 */
1523 	parity_protection_init();
1524 
1525 	/*
1526 	 * The Data Bus Errors / Instruction Bus Errors are signaled
1527 	 * by external hardware.  Therefore these two exceptions
1528 	 * may have board specific handlers.
1529 	 */
1530 	if (board_be_init)
1531 		board_be_init();
1532 
1533 	set_except_vector(0, handle_int);
1534 	set_except_vector(1, handle_tlbm);
1535 	set_except_vector(2, handle_tlbl);
1536 	set_except_vector(3, handle_tlbs);
1537 
1538 	set_except_vector(4, handle_adel);
1539 	set_except_vector(5, handle_ades);
1540 
1541 	set_except_vector(6, handle_ibe);
1542 	set_except_vector(7, handle_dbe);
1543 
1544 	set_except_vector(8, handle_sys);
1545 	set_except_vector(9, handle_bp);
1546 	set_except_vector(10, rdhwr_noopt ? handle_ri :
1547 			  (cpu_has_vtag_icache ?
1548 			   handle_ri_rdhwr_vivt : handle_ri_rdhwr));
1549 	set_except_vector(11, handle_cpu);
1550 	set_except_vector(12, handle_ov);
1551 	set_except_vector(13, handle_tr);
1552 
1553 	if (current_cpu_type() == CPU_R6000 ||
1554 	    current_cpu_type() == CPU_R6000A) {
1555 		/*
1556 		 * The R6000 is the only R-series CPU that features a machine
1557 		 * check exception (similar to the R4000 cache error) and
1558 		 * unaligned ldc1/sdc1 exception.  The handlers have not been
1559 		 * written yet.  Well, anyway there is no R6000 machine on the
1560 		 * current list of targets for Linux/MIPS.
1561 		 * (Duh, crap, there is someone with a triple R6k machine)
1562 		 */
1563 		//set_except_vector(14, handle_mc);
1564 		//set_except_vector(15, handle_ndc);
1565 	}
1566 
1567 
1568 	if (board_nmi_handler_setup)
1569 		board_nmi_handler_setup();
1570 
1571 	if (cpu_has_fpu && !cpu_has_nofpuex)
1572 		set_except_vector(15, handle_fpe);
1573 
1574 	set_except_vector(22, handle_mdmx);
1575 
1576 	if (cpu_has_mcheck)
1577 		set_except_vector(24, handle_mcheck);
1578 
1579 	if (cpu_has_mipsmt)
1580 		set_except_vector(25, handle_mt);
1581 
1582 	set_except_vector(26, handle_dsp);
1583 
1584 	if (cpu_has_vce)
1585 		/* Special exception: R4[04]00 uses also the divec space. */
1586 		memcpy((void *)(CAC_BASE + 0x180), &except_vec3_r4000, 0x100);
1587 	else if (cpu_has_4kex)
1588 		memcpy((void *)(CAC_BASE + 0x180), &except_vec3_generic, 0x80);
1589 	else
1590 		memcpy((void *)(CAC_BASE + 0x080), &except_vec3_generic, 0x80);
1591 
1592 	signal_init();
1593 #ifdef CONFIG_MIPS32_COMPAT
1594 	signal32_init();
1595 #endif
1596 
1597 	flush_icache_range(ebase, ebase + 0x400);
1598 	flush_tlb_handlers();
1599 }
1600