xref: /openbmc/linux/arch/mips/kernel/traps.c (revision 64c70b1c)
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 *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 #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\n", read_c0_prid());
299 }
300 
301 void show_registers(struct pt_regs *regs)
302 {
303 	show_regs(regs);
304 	print_modules();
305 	printk("Process %s (pid: %d, threadinfo=%p, task=%p)\n",
306 	        current->comm, current->pid, current_thread_info(), current);
307 	show_stacktrace(current, regs);
308 	show_code((unsigned int *) regs->cp0_epc);
309 	printk("\n");
310 }
311 
312 static DEFINE_SPINLOCK(die_lock);
313 
314 void __noreturn die(const char * str, struct pt_regs * regs)
315 {
316 	static int die_counter;
317 #ifdef CONFIG_MIPS_MT_SMTC
318 	unsigned long dvpret = dvpe();
319 #endif /* CONFIG_MIPS_MT_SMTC */
320 
321 	console_verbose();
322 	spin_lock_irq(&die_lock);
323 	bust_spinlocks(1);
324 #ifdef CONFIG_MIPS_MT_SMTC
325 	mips_mt_regdump(dvpret);
326 #endif /* CONFIG_MIPS_MT_SMTC */
327 	printk("%s[#%d]:\n", str, ++die_counter);
328 	show_registers(regs);
329 	spin_unlock_irq(&die_lock);
330 
331 	if (in_interrupt())
332 		panic("Fatal exception in interrupt");
333 
334 	if (panic_on_oops) {
335 		printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
336 		ssleep(5);
337 		panic("Fatal exception");
338 	}
339 
340 	do_exit(SIGSEGV);
341 }
342 
343 extern const struct exception_table_entry __start___dbe_table[];
344 extern const struct exception_table_entry __stop___dbe_table[];
345 
346 __asm__(
347 "	.section	__dbe_table, \"a\"\n"
348 "	.previous			\n");
349 
350 /* Given an address, look for it in the exception tables. */
351 static const struct exception_table_entry *search_dbe_tables(unsigned long addr)
352 {
353 	const struct exception_table_entry *e;
354 
355 	e = search_extable(__start___dbe_table, __stop___dbe_table - 1, addr);
356 	if (!e)
357 		e = search_module_dbetables(addr);
358 	return e;
359 }
360 
361 asmlinkage void do_be(struct pt_regs *regs)
362 {
363 	const int field = 2 * sizeof(unsigned long);
364 	const struct exception_table_entry *fixup = NULL;
365 	int data = regs->cp0_cause & 4;
366 	int action = MIPS_BE_FATAL;
367 
368 	/* XXX For now.  Fixme, this searches the wrong table ...  */
369 	if (data && !user_mode(regs))
370 		fixup = search_dbe_tables(exception_epc(regs));
371 
372 	if (fixup)
373 		action = MIPS_BE_FIXUP;
374 
375 	if (board_be_handler)
376 		action = board_be_handler(regs, fixup != 0);
377 
378 	switch (action) {
379 	case MIPS_BE_DISCARD:
380 		return;
381 	case MIPS_BE_FIXUP:
382 		if (fixup) {
383 			regs->cp0_epc = fixup->nextinsn;
384 			return;
385 		}
386 		break;
387 	default:
388 		break;
389 	}
390 
391 	/*
392 	 * Assume it would be too dangerous to continue ...
393 	 */
394 	printk(KERN_ALERT "%s bus error, epc == %0*lx, ra == %0*lx\n",
395 	       data ? "Data" : "Instruction",
396 	       field, regs->cp0_epc, field, regs->regs[31]);
397 	die_if_kernel("Oops", regs);
398 	force_sig(SIGBUS, current);
399 }
400 
401 /*
402  * ll/sc emulation
403  */
404 
405 #define OPCODE 0xfc000000
406 #define BASE   0x03e00000
407 #define RT     0x001f0000
408 #define OFFSET 0x0000ffff
409 #define LL     0xc0000000
410 #define SC     0xe0000000
411 #define SPEC3  0x7c000000
412 #define RD     0x0000f800
413 #define FUNC   0x0000003f
414 #define RDHWR  0x0000003b
415 
416 /*
417  * The ll_bit is cleared by r*_switch.S
418  */
419 
420 unsigned long ll_bit;
421 
422 static struct task_struct *ll_task = NULL;
423 
424 static inline void simulate_ll(struct pt_regs *regs, unsigned int opcode)
425 {
426 	unsigned long value, __user *vaddr;
427 	long offset;
428 	int signal = 0;
429 
430 	/*
431 	 * analyse the ll instruction that just caused a ri exception
432 	 * and put the referenced address to addr.
433 	 */
434 
435 	/* sign extend offset */
436 	offset = opcode & OFFSET;
437 	offset <<= 16;
438 	offset >>= 16;
439 
440 	vaddr = (unsigned long __user *)
441 	        ((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
442 
443 	if ((unsigned long)vaddr & 3) {
444 		signal = SIGBUS;
445 		goto sig;
446 	}
447 	if (get_user(value, vaddr)) {
448 		signal = SIGSEGV;
449 		goto sig;
450 	}
451 
452 	preempt_disable();
453 
454 	if (ll_task == NULL || ll_task == current) {
455 		ll_bit = 1;
456 	} else {
457 		ll_bit = 0;
458 	}
459 	ll_task = current;
460 
461 	preempt_enable();
462 
463 	compute_return_epc(regs);
464 
465 	regs->regs[(opcode & RT) >> 16] = value;
466 
467 	return;
468 
469 sig:
470 	force_sig(signal, current);
471 }
472 
473 static inline void simulate_sc(struct pt_regs *regs, unsigned int opcode)
474 {
475 	unsigned long __user *vaddr;
476 	unsigned long reg;
477 	long offset;
478 	int signal = 0;
479 
480 	/*
481 	 * analyse the sc instruction that just caused a ri exception
482 	 * and put the referenced address to addr.
483 	 */
484 
485 	/* sign extend offset */
486 	offset = opcode & OFFSET;
487 	offset <<= 16;
488 	offset >>= 16;
489 
490 	vaddr = (unsigned long __user *)
491 	        ((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
492 	reg = (opcode & RT) >> 16;
493 
494 	if ((unsigned long)vaddr & 3) {
495 		signal = SIGBUS;
496 		goto sig;
497 	}
498 
499 	preempt_disable();
500 
501 	if (ll_bit == 0 || ll_task != current) {
502 		compute_return_epc(regs);
503 		regs->regs[reg] = 0;
504 		preempt_enable();
505 		return;
506 	}
507 
508 	preempt_enable();
509 
510 	if (put_user(regs->regs[reg], vaddr)) {
511 		signal = SIGSEGV;
512 		goto sig;
513 	}
514 
515 	compute_return_epc(regs);
516 	regs->regs[reg] = 1;
517 
518 	return;
519 
520 sig:
521 	force_sig(signal, current);
522 }
523 
524 /*
525  * ll uses the opcode of lwc0 and sc uses the opcode of swc0.  That is both
526  * opcodes are supposed to result in coprocessor unusable exceptions if
527  * executed on ll/sc-less processors.  That's the theory.  In practice a
528  * few processors such as NEC's VR4100 throw reserved instruction exceptions
529  * instead, so we're doing the emulation thing in both exception handlers.
530  */
531 static inline int simulate_llsc(struct pt_regs *regs)
532 {
533 	unsigned int opcode;
534 
535 	if (get_user(opcode, (unsigned int __user *) exception_epc(regs)))
536 		goto out_sigsegv;
537 
538 	if ((opcode & OPCODE) == LL) {
539 		simulate_ll(regs, opcode);
540 		return 0;
541 	}
542 	if ((opcode & OPCODE) == SC) {
543 		simulate_sc(regs, opcode);
544 		return 0;
545 	}
546 
547 	return -EFAULT;			/* Strange things going on ... */
548 
549 out_sigsegv:
550 	force_sig(SIGSEGV, current);
551 	return -EFAULT;
552 }
553 
554 /*
555  * Simulate trapping 'rdhwr' instructions to provide user accessible
556  * registers not implemented in hardware.  The only current use of this
557  * is the thread area pointer.
558  */
559 static inline int simulate_rdhwr(struct pt_regs *regs)
560 {
561 	struct thread_info *ti = task_thread_info(current);
562 	unsigned int opcode;
563 
564 	if (get_user(opcode, (unsigned int __user *) exception_epc(regs)))
565 		goto out_sigsegv;
566 
567 	if (unlikely(compute_return_epc(regs)))
568 		return -EFAULT;
569 
570 	if ((opcode & OPCODE) == SPEC3 && (opcode & FUNC) == RDHWR) {
571 		int rd = (opcode & RD) >> 11;
572 		int rt = (opcode & RT) >> 16;
573 		switch (rd) {
574 			case 29:
575 				regs->regs[rt] = ti->tp_value;
576 				return 0;
577 			default:
578 				return -EFAULT;
579 		}
580 	}
581 
582 	/* Not ours.  */
583 	return -EFAULT;
584 
585 out_sigsegv:
586 	force_sig(SIGSEGV, current);
587 	return -EFAULT;
588 }
589 
590 asmlinkage void do_ov(struct pt_regs *regs)
591 {
592 	siginfo_t info;
593 
594 	die_if_kernel("Integer overflow", regs);
595 
596 	info.si_code = FPE_INTOVF;
597 	info.si_signo = SIGFPE;
598 	info.si_errno = 0;
599 	info.si_addr = (void __user *) regs->cp0_epc;
600 	force_sig_info(SIGFPE, &info, current);
601 }
602 
603 /*
604  * XXX Delayed fp exceptions when doing a lazy ctx switch XXX
605  */
606 asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
607 {
608 	die_if_kernel("FP exception in kernel code", regs);
609 
610 	if (fcr31 & FPU_CSR_UNI_X) {
611 		int sig;
612 
613 		/*
614 		 * Unimplemented operation exception.  If we've got the full
615 		 * software emulator on-board, let's use it...
616 		 *
617 		 * Force FPU to dump state into task/thread context.  We're
618 		 * moving a lot of data here for what is probably a single
619 		 * instruction, but the alternative is to pre-decode the FP
620 		 * register operands before invoking the emulator, which seems
621 		 * a bit extreme for what should be an infrequent event.
622 		 */
623 		/* Ensure 'resume' not overwrite saved fp context again. */
624 		lose_fpu(1);
625 
626 		/* Run the emulator */
627 		sig = fpu_emulator_cop1Handler (regs, &current->thread.fpu, 1);
628 
629 		/*
630 		 * We can't allow the emulated instruction to leave any of
631 		 * the cause bit set in $fcr31.
632 		 */
633 		current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
634 
635 		/* Restore the hardware register state */
636 		own_fpu(1);	/* Using the FPU again.  */
637 
638 		/* If something went wrong, signal */
639 		if (sig)
640 			force_sig(sig, current);
641 
642 		return;
643 	}
644 
645 	force_sig(SIGFPE, current);
646 }
647 
648 asmlinkage void do_bp(struct pt_regs *regs)
649 {
650 	unsigned int opcode, bcode;
651 	siginfo_t info;
652 
653 	if (__get_user(opcode, (unsigned int __user *) exception_epc(regs)))
654 		goto out_sigsegv;
655 
656 	/*
657 	 * There is the ancient bug in the MIPS assemblers that the break
658 	 * code starts left to bit 16 instead to bit 6 in the opcode.
659 	 * Gas is bug-compatible, but not always, grrr...
660 	 * We handle both cases with a simple heuristics.  --macro
661 	 */
662 	bcode = ((opcode >> 6) & ((1 << 20) - 1));
663 	if (bcode < (1 << 10))
664 		bcode <<= 10;
665 
666 	/*
667 	 * (A short test says that IRIX 5.3 sends SIGTRAP for all break
668 	 * insns, even for break codes that indicate arithmetic failures.
669 	 * Weird ...)
670 	 * But should we continue the brokenness???  --macro
671 	 */
672 	switch (bcode) {
673 	case BRK_OVERFLOW << 10:
674 	case BRK_DIVZERO << 10:
675 		die_if_kernel("Break instruction in kernel code", regs);
676 		if (bcode == (BRK_DIVZERO << 10))
677 			info.si_code = FPE_INTDIV;
678 		else
679 			info.si_code = FPE_INTOVF;
680 		info.si_signo = SIGFPE;
681 		info.si_errno = 0;
682 		info.si_addr = (void __user *) regs->cp0_epc;
683 		force_sig_info(SIGFPE, &info, current);
684 		break;
685 	case BRK_BUG:
686 		die("Kernel bug detected", regs);
687 		break;
688 	default:
689 		die_if_kernel("Break instruction in kernel code", regs);
690 		force_sig(SIGTRAP, current);
691 	}
692 	return;
693 
694 out_sigsegv:
695 	force_sig(SIGSEGV, current);
696 }
697 
698 asmlinkage void do_tr(struct pt_regs *regs)
699 {
700 	unsigned int opcode, tcode = 0;
701 	siginfo_t info;
702 
703 	if (__get_user(opcode, (unsigned int __user *) exception_epc(regs)))
704 		goto out_sigsegv;
705 
706 	/* Immediate versions don't provide a code.  */
707 	if (!(opcode & OPCODE))
708 		tcode = ((opcode >> 6) & ((1 << 10) - 1));
709 
710 	/*
711 	 * (A short test says that IRIX 5.3 sends SIGTRAP for all trap
712 	 * insns, even for trap codes that indicate arithmetic failures.
713 	 * Weird ...)
714 	 * But should we continue the brokenness???  --macro
715 	 */
716 	switch (tcode) {
717 	case BRK_OVERFLOW:
718 	case BRK_DIVZERO:
719 		die_if_kernel("Trap instruction in kernel code", regs);
720 		if (tcode == BRK_DIVZERO)
721 			info.si_code = FPE_INTDIV;
722 		else
723 			info.si_code = FPE_INTOVF;
724 		info.si_signo = SIGFPE;
725 		info.si_errno = 0;
726 		info.si_addr = (void __user *) regs->cp0_epc;
727 		force_sig_info(SIGFPE, &info, current);
728 		break;
729 	case BRK_BUG:
730 		die("Kernel bug detected", regs);
731 		break;
732 	default:
733 		die_if_kernel("Trap instruction in kernel code", regs);
734 		force_sig(SIGTRAP, current);
735 	}
736 	return;
737 
738 out_sigsegv:
739 	force_sig(SIGSEGV, current);
740 }
741 
742 asmlinkage void do_ri(struct pt_regs *regs)
743 {
744 	die_if_kernel("Reserved instruction in kernel code", regs);
745 
746 	if (!cpu_has_llsc)
747 		if (!simulate_llsc(regs))
748 			return;
749 
750 	if (!simulate_rdhwr(regs))
751 		return;
752 
753 	force_sig(SIGILL, current);
754 }
755 
756 /*
757  * MIPS MT processors may have fewer FPU contexts than CPU threads. If we've
758  * emulated more than some threshold number of instructions, force migration to
759  * a "CPU" that has FP support.
760  */
761 static void mt_ase_fp_affinity(void)
762 {
763 #ifdef CONFIG_MIPS_MT_FPAFF
764 	if (mt_fpemul_threshold > 0 &&
765 	     ((current->thread.emulated_fp++ > mt_fpemul_threshold))) {
766 		/*
767 		 * If there's no FPU present, or if the application has already
768 		 * restricted the allowed set to exclude any CPUs with FPUs,
769 		 * we'll skip the procedure.
770 		 */
771 		if (cpus_intersects(current->cpus_allowed, mt_fpu_cpumask)) {
772 			cpumask_t tmask;
773 
774 			cpus_and(tmask, current->thread.user_cpus_allowed,
775 			         mt_fpu_cpumask);
776 			set_cpus_allowed(current, tmask);
777 			current->thread.mflags |= MF_FPUBOUND;
778 		}
779 	}
780 #endif /* CONFIG_MIPS_MT_FPAFF */
781 }
782 
783 asmlinkage void do_cpu(struct pt_regs *regs)
784 {
785 	unsigned int cpid;
786 
787 	die_if_kernel("do_cpu invoked from kernel context!", regs);
788 
789 	cpid = (regs->cp0_cause >> CAUSEB_CE) & 3;
790 
791 	switch (cpid) {
792 	case 0:
793 		if (!cpu_has_llsc)
794 			if (!simulate_llsc(regs))
795 				return;
796 
797 		if (!simulate_rdhwr(regs))
798 			return;
799 
800 		break;
801 
802 	case 1:
803 		if (used_math())	/* Using the FPU again.  */
804 			own_fpu(1);
805 		else {			/* First time FPU user.  */
806 			init_fpu();
807 			set_used_math();
808 		}
809 
810 		if (!raw_cpu_has_fpu) {
811 			int sig;
812 			sig = fpu_emulator_cop1Handler(regs,
813 						&current->thread.fpu, 0);
814 			if (sig)
815 				force_sig(sig, current);
816 			else
817 				mt_ase_fp_affinity();
818 		}
819 
820 		return;
821 
822 	case 2:
823 	case 3:
824 		break;
825 	}
826 
827 	force_sig(SIGILL, current);
828 }
829 
830 asmlinkage void do_mdmx(struct pt_regs *regs)
831 {
832 	force_sig(SIGILL, current);
833 }
834 
835 asmlinkage void do_watch(struct pt_regs *regs)
836 {
837 	if (board_watchpoint_handler) {
838 		(*board_watchpoint_handler)(regs);
839 		return;
840 	}
841 
842 	/*
843 	 * We use the watch exception where available to detect stack
844 	 * overflows.
845 	 */
846 	dump_tlb_all();
847 	show_regs(regs);
848 	panic("Caught WATCH exception - probably caused by stack overflow.");
849 }
850 
851 asmlinkage void do_mcheck(struct pt_regs *regs)
852 {
853 	const int field = 2 * sizeof(unsigned long);
854 	int multi_match = regs->cp0_status & ST0_TS;
855 
856 	show_regs(regs);
857 
858 	if (multi_match) {
859 		printk("Index   : %0x\n", read_c0_index());
860 		printk("Pagemask: %0x\n", read_c0_pagemask());
861 		printk("EntryHi : %0*lx\n", field, read_c0_entryhi());
862 		printk("EntryLo0: %0*lx\n", field, read_c0_entrylo0());
863 		printk("EntryLo1: %0*lx\n", field, read_c0_entrylo1());
864 		printk("\n");
865 		dump_tlb_all();
866 	}
867 
868 	show_code((unsigned int *) regs->cp0_epc);
869 
870 	/*
871 	 * Some chips may have other causes of machine check (e.g. SB1
872 	 * graduation timer)
873 	 */
874 	panic("Caught Machine Check exception - %scaused by multiple "
875 	      "matching entries in the TLB.",
876 	      (multi_match) ? "" : "not ");
877 }
878 
879 asmlinkage void do_mt(struct pt_regs *regs)
880 {
881 	int subcode;
882 
883 	subcode = (read_vpe_c0_vpecontrol() & VPECONTROL_EXCPT)
884 			>> VPECONTROL_EXCPT_SHIFT;
885 	switch (subcode) {
886 	case 0:
887 		printk(KERN_DEBUG "Thread Underflow\n");
888 		break;
889 	case 1:
890 		printk(KERN_DEBUG "Thread Overflow\n");
891 		break;
892 	case 2:
893 		printk(KERN_DEBUG "Invalid YIELD Qualifier\n");
894 		break;
895 	case 3:
896 		printk(KERN_DEBUG "Gating Storage Exception\n");
897 		break;
898 	case 4:
899 		printk(KERN_DEBUG "YIELD Scheduler Exception\n");
900 		break;
901 	case 5:
902 		printk(KERN_DEBUG "Gating Storage Schedulier Exception\n");
903 		break;
904 	default:
905 		printk(KERN_DEBUG "*** UNKNOWN THREAD EXCEPTION %d ***\n",
906 			subcode);
907 		break;
908 	}
909 	die_if_kernel("MIPS MT Thread exception in kernel", regs);
910 
911 	force_sig(SIGILL, current);
912 }
913 
914 
915 asmlinkage void do_dsp(struct pt_regs *regs)
916 {
917 	if (cpu_has_dsp)
918 		panic("Unexpected DSP exception\n");
919 
920 	force_sig(SIGILL, current);
921 }
922 
923 asmlinkage void do_reserved(struct pt_regs *regs)
924 {
925 	/*
926 	 * Game over - no way to handle this if it ever occurs.  Most probably
927 	 * caused by a new unknown cpu type or after another deadly
928 	 * hard/software error.
929 	 */
930 	show_regs(regs);
931 	panic("Caught reserved exception %ld - should not happen.",
932 	      (regs->cp0_cause & 0x7f) >> 2);
933 }
934 
935 /*
936  * Some MIPS CPUs can enable/disable for cache parity detection, but do
937  * it different ways.
938  */
939 static inline void parity_protection_init(void)
940 {
941 	switch (current_cpu_data.cputype) {
942 	case CPU_24K:
943 	case CPU_34K:
944 	case CPU_5KC:
945 		write_c0_ecc(0x80000000);
946 		back_to_back_c0_hazard();
947 		/* Set the PE bit (bit 31) in the c0_errctl register. */
948 		printk(KERN_INFO "Cache parity protection %sabled\n",
949 		       (read_c0_ecc() & 0x80000000) ? "en" : "dis");
950 		break;
951 	case CPU_20KC:
952 	case CPU_25KF:
953 		/* Clear the DE bit (bit 16) in the c0_status register. */
954 		printk(KERN_INFO "Enable cache parity protection for "
955 		       "MIPS 20KC/25KF CPUs.\n");
956 		clear_c0_status(ST0_DE);
957 		break;
958 	default:
959 		break;
960 	}
961 }
962 
963 asmlinkage void cache_parity_error(void)
964 {
965 	const int field = 2 * sizeof(unsigned long);
966 	unsigned int reg_val;
967 
968 	/* For the moment, report the problem and hang. */
969 	printk("Cache error exception:\n");
970 	printk("cp0_errorepc == %0*lx\n", field, read_c0_errorepc());
971 	reg_val = read_c0_cacheerr();
972 	printk("c0_cacheerr == %08x\n", reg_val);
973 
974 	printk("Decoded c0_cacheerr: %s cache fault in %s reference.\n",
975 	       reg_val & (1<<30) ? "secondary" : "primary",
976 	       reg_val & (1<<31) ? "data" : "insn");
977 	printk("Error bits: %s%s%s%s%s%s%s\n",
978 	       reg_val & (1<<29) ? "ED " : "",
979 	       reg_val & (1<<28) ? "ET " : "",
980 	       reg_val & (1<<26) ? "EE " : "",
981 	       reg_val & (1<<25) ? "EB " : "",
982 	       reg_val & (1<<24) ? "EI " : "",
983 	       reg_val & (1<<23) ? "E1 " : "",
984 	       reg_val & (1<<22) ? "E0 " : "");
985 	printk("IDX: 0x%08x\n", reg_val & ((1<<22)-1));
986 
987 #if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
988 	if (reg_val & (1<<22))
989 		printk("DErrAddr0: 0x%0*lx\n", field, read_c0_derraddr0());
990 
991 	if (reg_val & (1<<23))
992 		printk("DErrAddr1: 0x%0*lx\n", field, read_c0_derraddr1());
993 #endif
994 
995 	panic("Can't handle the cache error!");
996 }
997 
998 /*
999  * SDBBP EJTAG debug exception handler.
1000  * We skip the instruction and return to the next instruction.
1001  */
1002 void ejtag_exception_handler(struct pt_regs *regs)
1003 {
1004 	const int field = 2 * sizeof(unsigned long);
1005 	unsigned long depc, old_epc;
1006 	unsigned int debug;
1007 
1008 	printk(KERN_DEBUG "SDBBP EJTAG debug exception - not handled yet, just ignored!\n");
1009 	depc = read_c0_depc();
1010 	debug = read_c0_debug();
1011 	printk(KERN_DEBUG "c0_depc = %0*lx, DEBUG = %08x\n", field, depc, debug);
1012 	if (debug & 0x80000000) {
1013 		/*
1014 		 * In branch delay slot.
1015 		 * We cheat a little bit here and use EPC to calculate the
1016 		 * debug return address (DEPC). EPC is restored after the
1017 		 * calculation.
1018 		 */
1019 		old_epc = regs->cp0_epc;
1020 		regs->cp0_epc = depc;
1021 		__compute_return_epc(regs);
1022 		depc = regs->cp0_epc;
1023 		regs->cp0_epc = old_epc;
1024 	} else
1025 		depc += 4;
1026 	write_c0_depc(depc);
1027 
1028 #if 0
1029 	printk(KERN_DEBUG "\n\n----- Enable EJTAG single stepping ----\n\n");
1030 	write_c0_debug(debug | 0x100);
1031 #endif
1032 }
1033 
1034 /*
1035  * NMI exception handler.
1036  */
1037 void nmi_exception_handler(struct pt_regs *regs)
1038 {
1039 #ifdef CONFIG_MIPS_MT_SMTC
1040 	unsigned long dvpret = dvpe();
1041 	bust_spinlocks(1);
1042 	printk("NMI taken!!!!\n");
1043 	mips_mt_regdump(dvpret);
1044 #else
1045 	bust_spinlocks(1);
1046 	printk("NMI taken!!!!\n");
1047 #endif /* CONFIG_MIPS_MT_SMTC */
1048 	die("NMI", regs);
1049 	while(1) ;
1050 }
1051 
1052 #define VECTORSPACING 0x100	/* for EI/VI mode */
1053 
1054 unsigned long ebase;
1055 unsigned long exception_handlers[32];
1056 unsigned long vi_handlers[64];
1057 
1058 /*
1059  * As a side effect of the way this is implemented we're limited
1060  * to interrupt handlers in the address range from
1061  * KSEG0 <= x < KSEG0 + 256mb on the Nevada.  Oh well ...
1062  */
1063 void *set_except_vector(int n, void *addr)
1064 {
1065 	unsigned long handler = (unsigned long) addr;
1066 	unsigned long old_handler = exception_handlers[n];
1067 
1068 	exception_handlers[n] = handler;
1069 	if (n == 0 && cpu_has_divec) {
1070 		*(volatile u32 *)(ebase + 0x200) = 0x08000000 |
1071 		                                 (0x03ffffff & (handler >> 2));
1072 		flush_icache_range(ebase + 0x200, ebase + 0x204);
1073 	}
1074 	return (void *)old_handler;
1075 }
1076 
1077 #ifdef CONFIG_CPU_MIPSR2_SRS
1078 /*
1079  * MIPSR2 shadow register set allocation
1080  * FIXME: SMP...
1081  */
1082 
1083 static struct shadow_registers {
1084 	/*
1085 	 * Number of shadow register sets supported
1086 	 */
1087 	unsigned long sr_supported;
1088 	/*
1089 	 * Bitmap of allocated shadow registers
1090 	 */
1091 	unsigned long sr_allocated;
1092 } shadow_registers;
1093 
1094 static void mips_srs_init(void)
1095 {
1096 	shadow_registers.sr_supported = ((read_c0_srsctl() >> 26) & 0x0f) + 1;
1097 	printk(KERN_INFO "%ld MIPSR2 register sets available\n",
1098 	       shadow_registers.sr_supported);
1099 	shadow_registers.sr_allocated = 1;	/* Set 0 used by kernel */
1100 }
1101 
1102 int mips_srs_max(void)
1103 {
1104 	return shadow_registers.sr_supported;
1105 }
1106 
1107 int mips_srs_alloc(void)
1108 {
1109 	struct shadow_registers *sr = &shadow_registers;
1110 	int set;
1111 
1112 again:
1113 	set = find_first_zero_bit(&sr->sr_allocated, sr->sr_supported);
1114 	if (set >= sr->sr_supported)
1115 		return -1;
1116 
1117 	if (test_and_set_bit(set, &sr->sr_allocated))
1118 		goto again;
1119 
1120 	return set;
1121 }
1122 
1123 void mips_srs_free(int set)
1124 {
1125 	struct shadow_registers *sr = &shadow_registers;
1126 
1127 	clear_bit(set, &sr->sr_allocated);
1128 }
1129 
1130 static asmlinkage void do_default_vi(void)
1131 {
1132 	show_regs(get_irq_regs());
1133 	panic("Caught unexpected vectored interrupt.");
1134 }
1135 
1136 static void *set_vi_srs_handler(int n, vi_handler_t addr, int srs)
1137 {
1138 	unsigned long handler;
1139 	unsigned long old_handler = vi_handlers[n];
1140 	u32 *w;
1141 	unsigned char *b;
1142 
1143 	if (!cpu_has_veic && !cpu_has_vint)
1144 		BUG();
1145 
1146 	if (addr == NULL) {
1147 		handler = (unsigned long) do_default_vi;
1148 		srs = 0;
1149 	} else
1150 		handler = (unsigned long) addr;
1151 	vi_handlers[n] = (unsigned long) addr;
1152 
1153 	b = (unsigned char *)(ebase + 0x200 + n*VECTORSPACING);
1154 
1155 	if (srs >= mips_srs_max())
1156 		panic("Shadow register set %d not supported", srs);
1157 
1158 	if (cpu_has_veic) {
1159 		if (board_bind_eic_interrupt)
1160 			board_bind_eic_interrupt (n, srs);
1161 	} else if (cpu_has_vint) {
1162 		/* SRSMap is only defined if shadow sets are implemented */
1163 		if (mips_srs_max() > 1)
1164 			change_c0_srsmap (0xf << n*4, srs << n*4);
1165 	}
1166 
1167 	if (srs == 0) {
1168 		/*
1169 		 * If no shadow set is selected then use the default handler
1170 		 * that does normal register saving and a standard interrupt exit
1171 		 */
1172 
1173 		extern char except_vec_vi, except_vec_vi_lui;
1174 		extern char except_vec_vi_ori, except_vec_vi_end;
1175 #ifdef CONFIG_MIPS_MT_SMTC
1176 		/*
1177 		 * We need to provide the SMTC vectored interrupt handler
1178 		 * not only with the address of the handler, but with the
1179 		 * Status.IM bit to be masked before going there.
1180 		 */
1181 		extern char except_vec_vi_mori;
1182 		const int mori_offset = &except_vec_vi_mori - &except_vec_vi;
1183 #endif /* CONFIG_MIPS_MT_SMTC */
1184 		const int handler_len = &except_vec_vi_end - &except_vec_vi;
1185 		const int lui_offset = &except_vec_vi_lui - &except_vec_vi;
1186 		const int ori_offset = &except_vec_vi_ori - &except_vec_vi;
1187 
1188 		if (handler_len > VECTORSPACING) {
1189 			/*
1190 			 * Sigh... panicing won't help as the console
1191 			 * is probably not configured :(
1192 			 */
1193 			panic ("VECTORSPACING too small");
1194 		}
1195 
1196 		memcpy (b, &except_vec_vi, handler_len);
1197 #ifdef CONFIG_MIPS_MT_SMTC
1198 		BUG_ON(n > 7);	/* Vector index %d exceeds SMTC maximum. */
1199 
1200 		w = (u32 *)(b + mori_offset);
1201 		*w = (*w & 0xffff0000) | (0x100 << n);
1202 #endif /* CONFIG_MIPS_MT_SMTC */
1203 		w = (u32 *)(b + lui_offset);
1204 		*w = (*w & 0xffff0000) | (((u32)handler >> 16) & 0xffff);
1205 		w = (u32 *)(b + ori_offset);
1206 		*w = (*w & 0xffff0000) | ((u32)handler & 0xffff);
1207 		flush_icache_range((unsigned long)b, (unsigned long)(b+handler_len));
1208 	}
1209 	else {
1210 		/*
1211 		 * In other cases jump directly to the interrupt handler
1212 		 *
1213 		 * It is the handlers responsibility to save registers if required
1214 		 * (eg hi/lo) and return from the exception using "eret"
1215 		 */
1216 		w = (u32 *)b;
1217 		*w++ = 0x08000000 | (((u32)handler >> 2) & 0x03fffff); /* j handler */
1218 		*w = 0;
1219 		flush_icache_range((unsigned long)b, (unsigned long)(b+8));
1220 	}
1221 
1222 	return (void *)old_handler;
1223 }
1224 
1225 void *set_vi_handler(int n, vi_handler_t addr)
1226 {
1227 	return set_vi_srs_handler(n, addr, 0);
1228 }
1229 
1230 #else
1231 
1232 static inline void mips_srs_init(void)
1233 {
1234 }
1235 
1236 #endif /* CONFIG_CPU_MIPSR2_SRS */
1237 
1238 /*
1239  * This is used by native signal handling
1240  */
1241 asmlinkage int (*save_fp_context)(struct sigcontext __user *sc);
1242 asmlinkage int (*restore_fp_context)(struct sigcontext __user *sc);
1243 
1244 extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
1245 extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
1246 
1247 extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc);
1248 extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc);
1249 
1250 #ifdef CONFIG_SMP
1251 static int smp_save_fp_context(struct sigcontext __user *sc)
1252 {
1253 	return raw_cpu_has_fpu
1254 	       ? _save_fp_context(sc)
1255 	       : fpu_emulator_save_context(sc);
1256 }
1257 
1258 static int smp_restore_fp_context(struct sigcontext __user *sc)
1259 {
1260 	return raw_cpu_has_fpu
1261 	       ? _restore_fp_context(sc)
1262 	       : fpu_emulator_restore_context(sc);
1263 }
1264 #endif
1265 
1266 static inline void signal_init(void)
1267 {
1268 #ifdef CONFIG_SMP
1269 	/* For now just do the cpu_has_fpu check when the functions are invoked */
1270 	save_fp_context = smp_save_fp_context;
1271 	restore_fp_context = smp_restore_fp_context;
1272 #else
1273 	if (cpu_has_fpu) {
1274 		save_fp_context = _save_fp_context;
1275 		restore_fp_context = _restore_fp_context;
1276 	} else {
1277 		save_fp_context = fpu_emulator_save_context;
1278 		restore_fp_context = fpu_emulator_restore_context;
1279 	}
1280 #endif
1281 }
1282 
1283 #ifdef CONFIG_MIPS32_COMPAT
1284 
1285 /*
1286  * This is used by 32-bit signal stuff on the 64-bit kernel
1287  */
1288 asmlinkage int (*save_fp_context32)(struct sigcontext32 __user *sc);
1289 asmlinkage int (*restore_fp_context32)(struct sigcontext32 __user *sc);
1290 
1291 extern asmlinkage int _save_fp_context32(struct sigcontext32 __user *sc);
1292 extern asmlinkage int _restore_fp_context32(struct sigcontext32 __user *sc);
1293 
1294 extern asmlinkage int fpu_emulator_save_context32(struct sigcontext32 __user *sc);
1295 extern asmlinkage int fpu_emulator_restore_context32(struct sigcontext32 __user *sc);
1296 
1297 static inline void signal32_init(void)
1298 {
1299 	if (cpu_has_fpu) {
1300 		save_fp_context32 = _save_fp_context32;
1301 		restore_fp_context32 = _restore_fp_context32;
1302 	} else {
1303 		save_fp_context32 = fpu_emulator_save_context32;
1304 		restore_fp_context32 = fpu_emulator_restore_context32;
1305 	}
1306 }
1307 #endif
1308 
1309 extern void cpu_cache_init(void);
1310 extern void tlb_init(void);
1311 extern void flush_tlb_handlers(void);
1312 
1313 void __init per_cpu_trap_init(void)
1314 {
1315 	unsigned int cpu = smp_processor_id();
1316 	unsigned int status_set = ST0_CU0;
1317 #ifdef CONFIG_MIPS_MT_SMTC
1318 	int secondaryTC = 0;
1319 	int bootTC = (cpu == 0);
1320 
1321 	/*
1322 	 * Only do per_cpu_trap_init() for first TC of Each VPE.
1323 	 * Note that this hack assumes that the SMTC init code
1324 	 * assigns TCs consecutively and in ascending order.
1325 	 */
1326 
1327 	if (((read_c0_tcbind() & TCBIND_CURTC) != 0) &&
1328 	    ((read_c0_tcbind() & TCBIND_CURVPE) == cpu_data[cpu - 1].vpe_id))
1329 		secondaryTC = 1;
1330 #endif /* CONFIG_MIPS_MT_SMTC */
1331 
1332 	/*
1333 	 * Disable coprocessors and select 32-bit or 64-bit addressing
1334 	 * and the 16/32 or 32/32 FPR register model.  Reset the BEV
1335 	 * flag that some firmware may have left set and the TS bit (for
1336 	 * IP27).  Set XX for ISA IV code to work.
1337 	 */
1338 #ifdef CONFIG_64BIT
1339 	status_set |= ST0_FR|ST0_KX|ST0_SX|ST0_UX;
1340 #endif
1341 	if (current_cpu_data.isa_level == MIPS_CPU_ISA_IV)
1342 		status_set |= ST0_XX;
1343 	change_c0_status(ST0_CU|ST0_MX|ST0_RE|ST0_FR|ST0_BEV|ST0_TS|ST0_KX|ST0_SX|ST0_UX,
1344 			 status_set);
1345 
1346 	if (cpu_has_dsp)
1347 		set_c0_status(ST0_MX);
1348 
1349 #ifdef CONFIG_CPU_MIPSR2
1350 	if (cpu_has_mips_r2) {
1351 		unsigned int enable = 0x0000000f;
1352 
1353 		if (cpu_has_userlocal)
1354 			enable |= (1 << 29);
1355 
1356 		write_c0_hwrena(enable);
1357 	}
1358 #endif
1359 
1360 #ifdef CONFIG_MIPS_MT_SMTC
1361 	if (!secondaryTC) {
1362 #endif /* CONFIG_MIPS_MT_SMTC */
1363 
1364 	if (cpu_has_veic || cpu_has_vint) {
1365 		write_c0_ebase (ebase);
1366 		/* Setting vector spacing enables EI/VI mode  */
1367 		change_c0_intctl (0x3e0, VECTORSPACING);
1368 	}
1369 	if (cpu_has_divec) {
1370 		if (cpu_has_mipsmt) {
1371 			unsigned int vpflags = dvpe();
1372 			set_c0_cause(CAUSEF_IV);
1373 			evpe(vpflags);
1374 		} else
1375 			set_c0_cause(CAUSEF_IV);
1376 	}
1377 
1378 	/*
1379 	 * Before R2 both interrupt numbers were fixed to 7, so on R2 only:
1380 	 *
1381 	 *  o read IntCtl.IPTI to determine the timer interrupt
1382 	 *  o read IntCtl.IPPCI to determine the performance counter interrupt
1383 	 */
1384 	if (cpu_has_mips_r2) {
1385 		cp0_compare_irq = (read_c0_intctl () >> 29) & 7;
1386 		cp0_perfcount_irq = (read_c0_intctl () >> 26) & 7;
1387 		if (cp0_perfcount_irq == cp0_compare_irq)
1388 			cp0_perfcount_irq = -1;
1389 	} else {
1390 		cp0_compare_irq = CP0_LEGACY_COMPARE_IRQ;
1391 		cp0_perfcount_irq = -1;
1392 	}
1393 
1394 #ifdef CONFIG_MIPS_MT_SMTC
1395 	}
1396 #endif /* CONFIG_MIPS_MT_SMTC */
1397 
1398 	cpu_data[cpu].asid_cache = ASID_FIRST_VERSION;
1399 	TLBMISS_HANDLER_SETUP();
1400 
1401 	atomic_inc(&init_mm.mm_count);
1402 	current->active_mm = &init_mm;
1403 	BUG_ON(current->mm);
1404 	enter_lazy_tlb(&init_mm, current);
1405 
1406 #ifdef CONFIG_MIPS_MT_SMTC
1407 	if (bootTC) {
1408 #endif /* CONFIG_MIPS_MT_SMTC */
1409 		cpu_cache_init();
1410 		tlb_init();
1411 #ifdef CONFIG_MIPS_MT_SMTC
1412 	} else if (!secondaryTC) {
1413 		/*
1414 		 * First TC in non-boot VPE must do subset of tlb_init()
1415 		 * for MMU countrol registers.
1416 		 */
1417 		write_c0_pagemask(PM_DEFAULT_MASK);
1418 		write_c0_wired(0);
1419 	}
1420 #endif /* CONFIG_MIPS_MT_SMTC */
1421 }
1422 
1423 /* Install CPU exception handler */
1424 void __init set_handler (unsigned long offset, void *addr, unsigned long size)
1425 {
1426 	memcpy((void *)(ebase + offset), addr, size);
1427 	flush_icache_range(ebase + offset, ebase + offset + size);
1428 }
1429 
1430 /* Install uncached CPU exception handler */
1431 void __init set_uncached_handler (unsigned long offset, void *addr, unsigned long size)
1432 {
1433 #ifdef CONFIG_32BIT
1434 	unsigned long uncached_ebase = KSEG1ADDR(ebase);
1435 #endif
1436 #ifdef CONFIG_64BIT
1437 	unsigned long uncached_ebase = TO_UNCAC(ebase);
1438 #endif
1439 
1440 	memcpy((void *)(uncached_ebase + offset), addr, size);
1441 }
1442 
1443 static int __initdata rdhwr_noopt;
1444 static int __init set_rdhwr_noopt(char *str)
1445 {
1446 	rdhwr_noopt = 1;
1447 	return 1;
1448 }
1449 
1450 __setup("rdhwr_noopt", set_rdhwr_noopt);
1451 
1452 void __init trap_init(void)
1453 {
1454 	extern char except_vec3_generic, except_vec3_r4000;
1455 	extern char except_vec4;
1456 	unsigned long i;
1457 
1458 	if (cpu_has_veic || cpu_has_vint)
1459 		ebase = (unsigned long) alloc_bootmem_low_pages (0x200 + VECTORSPACING*64);
1460 	else
1461 		ebase = CAC_BASE;
1462 
1463 	mips_srs_init();
1464 
1465 	per_cpu_trap_init();
1466 
1467 	/*
1468 	 * Copy the generic exception handlers to their final destination.
1469 	 * This will be overriden later as suitable for a particular
1470 	 * configuration.
1471 	 */
1472 	set_handler(0x180, &except_vec3_generic, 0x80);
1473 
1474 	/*
1475 	 * Setup default vectors
1476 	 */
1477 	for (i = 0; i <= 31; i++)
1478 		set_except_vector(i, handle_reserved);
1479 
1480 	/*
1481 	 * Copy the EJTAG debug exception vector handler code to it's final
1482 	 * destination.
1483 	 */
1484 	if (cpu_has_ejtag && board_ejtag_handler_setup)
1485 		board_ejtag_handler_setup ();
1486 
1487 	/*
1488 	 * Only some CPUs have the watch exceptions.
1489 	 */
1490 	if (cpu_has_watch)
1491 		set_except_vector(23, handle_watch);
1492 
1493 	/*
1494 	 * Initialise interrupt handlers
1495 	 */
1496 	if (cpu_has_veic || cpu_has_vint) {
1497 		int nvec = cpu_has_veic ? 64 : 8;
1498 		for (i = 0; i < nvec; i++)
1499 			set_vi_handler(i, NULL);
1500 	}
1501 	else if (cpu_has_divec)
1502 		set_handler(0x200, &except_vec4, 0x8);
1503 
1504 	/*
1505 	 * Some CPUs can enable/disable for cache parity detection, but does
1506 	 * it different ways.
1507 	 */
1508 	parity_protection_init();
1509 
1510 	/*
1511 	 * The Data Bus Errors / Instruction Bus Errors are signaled
1512 	 * by external hardware.  Therefore these two exceptions
1513 	 * may have board specific handlers.
1514 	 */
1515 	if (board_be_init)
1516 		board_be_init();
1517 
1518 	set_except_vector(0, handle_int);
1519 	set_except_vector(1, handle_tlbm);
1520 	set_except_vector(2, handle_tlbl);
1521 	set_except_vector(3, handle_tlbs);
1522 
1523 	set_except_vector(4, handle_adel);
1524 	set_except_vector(5, handle_ades);
1525 
1526 	set_except_vector(6, handle_ibe);
1527 	set_except_vector(7, handle_dbe);
1528 
1529 	set_except_vector(8, handle_sys);
1530 	set_except_vector(9, handle_bp);
1531 	set_except_vector(10, rdhwr_noopt ? handle_ri :
1532 			  (cpu_has_vtag_icache ?
1533 			   handle_ri_rdhwr_vivt : handle_ri_rdhwr));
1534 	set_except_vector(11, handle_cpu);
1535 	set_except_vector(12, handle_ov);
1536 	set_except_vector(13, handle_tr);
1537 
1538 	if (current_cpu_data.cputype == CPU_R6000 ||
1539 	    current_cpu_data.cputype == CPU_R6000A) {
1540 		/*
1541 		 * The R6000 is the only R-series CPU that features a machine
1542 		 * check exception (similar to the R4000 cache error) and
1543 		 * unaligned ldc1/sdc1 exception.  The handlers have not been
1544 		 * written yet.  Well, anyway there is no R6000 machine on the
1545 		 * current list of targets for Linux/MIPS.
1546 		 * (Duh, crap, there is someone with a triple R6k machine)
1547 		 */
1548 		//set_except_vector(14, handle_mc);
1549 		//set_except_vector(15, handle_ndc);
1550 	}
1551 
1552 
1553 	if (board_nmi_handler_setup)
1554 		board_nmi_handler_setup();
1555 
1556 	if (cpu_has_fpu && !cpu_has_nofpuex)
1557 		set_except_vector(15, handle_fpe);
1558 
1559 	set_except_vector(22, handle_mdmx);
1560 
1561 	if (cpu_has_mcheck)
1562 		set_except_vector(24, handle_mcheck);
1563 
1564 	if (cpu_has_mipsmt)
1565 		set_except_vector(25, handle_mt);
1566 
1567 	set_except_vector(26, handle_dsp);
1568 
1569 	if (cpu_has_vce)
1570 		/* Special exception: R4[04]00 uses also the divec space. */
1571 		memcpy((void *)(CAC_BASE + 0x180), &except_vec3_r4000, 0x100);
1572 	else if (cpu_has_4kex)
1573 		memcpy((void *)(CAC_BASE + 0x180), &except_vec3_generic, 0x80);
1574 	else
1575 		memcpy((void *)(CAC_BASE + 0x080), &except_vec3_generic, 0x80);
1576 
1577 	signal_init();
1578 #ifdef CONFIG_MIPS32_COMPAT
1579 	signal32_init();
1580 #endif
1581 
1582 	flush_icache_range(ebase, ebase + 0x400);
1583 	flush_tlb_handlers();
1584 }
1585