xref: /linux/arch/mips/kernel/traps.c (revision f7511d5f66f01fc451747b24e79f3ada7a3af9af)
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, 2007  Maciej W. Rozycki
13  */
14 #include <linux/bug.h>
15 #include <linux/compiler.h>
16 #include <linux/init.h>
17 #include <linux/mm.h>
18 #include <linux/module.h>
19 #include <linux/sched.h>
20 #include <linux/smp.h>
21 #include <linux/spinlock.h>
22 #include <linux/kallsyms.h>
23 #include <linux/bootmem.h>
24 #include <linux/interrupt.h>
25 #include <linux/ptrace.h>
26 
27 #include <asm/bootinfo.h>
28 #include <asm/branch.h>
29 #include <asm/break.h>
30 #include <asm/cpu.h>
31 #include <asm/dsp.h>
32 #include <asm/fpu.h>
33 #include <asm/mipsregs.h>
34 #include <asm/mipsmtregs.h>
35 #include <asm/module.h>
36 #include <asm/pgtable.h>
37 #include <asm/ptrace.h>
38 #include <asm/sections.h>
39 #include <asm/system.h>
40 #include <asm/tlbdebug.h>
41 #include <asm/traps.h>
42 #include <asm/uaccess.h>
43 #include <asm/mmu_context.h>
44 #include <asm/types.h>
45 #include <asm/stacktrace.h>
46 
47 extern asmlinkage void handle_int(void);
48 extern asmlinkage void handle_tlbm(void);
49 extern asmlinkage void handle_tlbl(void);
50 extern asmlinkage void handle_tlbs(void);
51 extern asmlinkage void handle_adel(void);
52 extern asmlinkage void handle_ades(void);
53 extern asmlinkage void handle_ibe(void);
54 extern asmlinkage void handle_dbe(void);
55 extern asmlinkage void handle_sys(void);
56 extern asmlinkage void handle_bp(void);
57 extern asmlinkage void handle_ri(void);
58 extern asmlinkage void handle_ri_rdhwr_vivt(void);
59 extern asmlinkage void handle_ri_rdhwr(void);
60 extern asmlinkage void handle_cpu(void);
61 extern asmlinkage void handle_ov(void);
62 extern asmlinkage void handle_tr(void);
63 extern asmlinkage void handle_fpe(void);
64 extern asmlinkage void handle_mdmx(void);
65 extern asmlinkage void handle_watch(void);
66 extern asmlinkage void handle_mt(void);
67 extern asmlinkage void handle_dsp(void);
68 extern asmlinkage void handle_mcheck(void);
69 extern asmlinkage void handle_reserved(void);
70 
71 extern int fpu_emulator_cop1Handler(struct pt_regs *xcp,
72 	struct mips_fpu_struct *ctx, int has_fpu);
73 
74 void (*board_watchpoint_handler)(struct pt_regs *regs);
75 void (*board_be_init)(void);
76 int (*board_be_handler)(struct pt_regs *regs, int is_fixup);
77 void (*board_nmi_handler_setup)(void);
78 void (*board_ejtag_handler_setup)(void);
79 void (*board_bind_eic_interrupt)(int irq, int regset);
80 
81 
82 static void show_raw_backtrace(unsigned long reg29)
83 {
84 	unsigned long *sp = (unsigned long *)(reg29 & ~3);
85 	unsigned long addr;
86 
87 	printk("Call Trace:");
88 #ifdef CONFIG_KALLSYMS
89 	printk("\n");
90 #endif
91 #define IS_KVA01(a) ((((unsigned int)a) & 0xc0000000) == 0x80000000)
92 	if (IS_KVA01(sp)) {
93 		while (!kstack_end(sp)) {
94 			addr = *sp++;
95 			if (__kernel_text_address(addr))
96 				print_ip_sym(addr);
97 		}
98 		printk("\n");
99 	}
100 }
101 
102 #ifdef CONFIG_KALLSYMS
103 int raw_show_trace;
104 static int __init set_raw_show_trace(char *str)
105 {
106 	raw_show_trace = 1;
107 	return 1;
108 }
109 __setup("raw_show_trace", set_raw_show_trace);
110 #endif
111 
112 static void show_backtrace(struct task_struct *task, const struct pt_regs *regs)
113 {
114 	unsigned long sp = regs->regs[29];
115 	unsigned long ra = regs->regs[31];
116 	unsigned long pc = regs->cp0_epc;
117 
118 	if (raw_show_trace || !__kernel_text_address(pc)) {
119 		show_raw_backtrace(sp);
120 		return;
121 	}
122 	printk("Call Trace:\n");
123 	do {
124 		print_ip_sym(pc);
125 		pc = unwind_stack(task, &sp, pc, &ra);
126 	} while (pc);
127 	printk("\n");
128 }
129 
130 /*
131  * This routine abuses get_user()/put_user() to reference pointers
132  * with at least a bit of error checking ...
133  */
134 static void show_stacktrace(struct task_struct *task,
135 	const struct pt_regs *regs)
136 {
137 	const int field = 2 * sizeof(unsigned long);
138 	long stackdata;
139 	int i;
140 	unsigned long __user *sp = (unsigned long __user *)regs->regs[29];
141 
142 	printk("Stack :");
143 	i = 0;
144 	while ((unsigned long) sp & (PAGE_SIZE - 1)) {
145 		if (i && ((i % (64 / field)) == 0))
146 			printk("\n       ");
147 		if (i > 39) {
148 			printk(" ...");
149 			break;
150 		}
151 
152 		if (__get_user(stackdata, sp++)) {
153 			printk(" (Bad stack address)");
154 			break;
155 		}
156 
157 		printk(" %0*lx", field, stackdata);
158 		i++;
159 	}
160 	printk("\n");
161 	show_backtrace(task, regs);
162 }
163 
164 void show_stack(struct task_struct *task, unsigned long *sp)
165 {
166 	struct pt_regs regs;
167 	if (sp) {
168 		regs.regs[29] = (unsigned long)sp;
169 		regs.regs[31] = 0;
170 		regs.cp0_epc = 0;
171 	} else {
172 		if (task && task != current) {
173 			regs.regs[29] = task->thread.reg29;
174 			regs.regs[31] = 0;
175 			regs.cp0_epc = task->thread.reg31;
176 		} else {
177 			prepare_frametrace(&regs);
178 		}
179 	}
180 	show_stacktrace(task, &regs);
181 }
182 
183 /*
184  * The architecture-independent dump_stack generator
185  */
186 void dump_stack(void)
187 {
188 	struct pt_regs regs;
189 
190 	prepare_frametrace(&regs);
191 	show_backtrace(current, &regs);
192 }
193 
194 EXPORT_SYMBOL(dump_stack);
195 
196 static void show_code(unsigned int __user *pc)
197 {
198 	long i;
199 	unsigned short __user *pc16 = NULL;
200 
201 	printk("\nCode:");
202 
203 	if ((unsigned long)pc & 1)
204 		pc16 = (unsigned short __user *)((unsigned long)pc & ~1);
205 	for(i = -3 ; i < 6 ; i++) {
206 		unsigned int insn;
207 		if (pc16 ? __get_user(insn, pc16 + i) : __get_user(insn, pc + i)) {
208 			printk(" (Bad address in epc)\n");
209 			break;
210 		}
211 		printk("%c%0*x%c", (i?' ':'<'), pc16 ? 4 : 8, insn, (i?' ':'>'));
212 	}
213 }
214 
215 static void __show_regs(const struct pt_regs *regs)
216 {
217 	const int field = 2 * sizeof(unsigned long);
218 	unsigned int cause = regs->cp0_cause;
219 	int i;
220 
221 	printk("Cpu %d\n", smp_processor_id());
222 
223 	/*
224 	 * Saved main processor registers
225 	 */
226 	for (i = 0; i < 32; ) {
227 		if ((i % 4) == 0)
228 			printk("$%2d   :", i);
229 		if (i == 0)
230 			printk(" %0*lx", field, 0UL);
231 		else if (i == 26 || i == 27)
232 			printk(" %*s", field, "");
233 		else
234 			printk(" %0*lx", field, regs->regs[i]);
235 
236 		i++;
237 		if ((i % 4) == 0)
238 			printk("\n");
239 	}
240 
241 #ifdef CONFIG_CPU_HAS_SMARTMIPS
242 	printk("Acx    : %0*lx\n", field, regs->acx);
243 #endif
244 	printk("Hi    : %0*lx\n", field, regs->hi);
245 	printk("Lo    : %0*lx\n", field, regs->lo);
246 
247 	/*
248 	 * Saved cp0 registers
249 	 */
250 	printk("epc   : %0*lx ", field, regs->cp0_epc);
251 	print_symbol("%s ", regs->cp0_epc);
252 	printk("    %s\n", print_tainted());
253 	printk("ra    : %0*lx ", field, regs->regs[31]);
254 	print_symbol("%s\n", regs->regs[31]);
255 
256 	printk("Status: %08x    ", (uint32_t) regs->cp0_status);
257 
258 	if (current_cpu_data.isa_level == MIPS_CPU_ISA_I) {
259 		if (regs->cp0_status & ST0_KUO)
260 			printk("KUo ");
261 		if (regs->cp0_status & ST0_IEO)
262 			printk("IEo ");
263 		if (regs->cp0_status & ST0_KUP)
264 			printk("KUp ");
265 		if (regs->cp0_status & ST0_IEP)
266 			printk("IEp ");
267 		if (regs->cp0_status & ST0_KUC)
268 			printk("KUc ");
269 		if (regs->cp0_status & ST0_IEC)
270 			printk("IEc ");
271 	} else {
272 		if (regs->cp0_status & ST0_KX)
273 			printk("KX ");
274 		if (regs->cp0_status & ST0_SX)
275 			printk("SX ");
276 		if (regs->cp0_status & ST0_UX)
277 			printk("UX ");
278 		switch (regs->cp0_status & ST0_KSU) {
279 		case KSU_USER:
280 			printk("USER ");
281 			break;
282 		case KSU_SUPERVISOR:
283 			printk("SUPERVISOR ");
284 			break;
285 		case KSU_KERNEL:
286 			printk("KERNEL ");
287 			break;
288 		default:
289 			printk("BAD_MODE ");
290 			break;
291 		}
292 		if (regs->cp0_status & ST0_ERL)
293 			printk("ERL ");
294 		if (regs->cp0_status & ST0_EXL)
295 			printk("EXL ");
296 		if (regs->cp0_status & ST0_IE)
297 			printk("IE ");
298 	}
299 	printk("\n");
300 
301 	printk("Cause : %08x\n", cause);
302 
303 	cause = (cause & CAUSEF_EXCCODE) >> CAUSEB_EXCCODE;
304 	if (1 <= cause && cause <= 5)
305 		printk("BadVA : %0*lx\n", field, regs->cp0_badvaddr);
306 
307 	printk("PrId  : %08x (%s)\n", read_c0_prid(),
308 	       cpu_name_string());
309 }
310 
311 /*
312  * FIXME: really the generic show_regs should take a const pointer argument.
313  */
314 void show_regs(struct pt_regs *regs)
315 {
316 	__show_regs((struct pt_regs *)regs);
317 }
318 
319 void show_registers(const struct pt_regs *regs)
320 {
321 	const int field = 2 * sizeof(unsigned long);
322 
323 	__show_regs(regs);
324 	print_modules();
325 	printk("Process %s (pid: %d, threadinfo=%p, task=%p, tls=%0*lx)\n",
326 	       current->comm, current->pid, current_thread_info(), current,
327 	      field, current_thread_info()->tp_value);
328 	if (cpu_has_userlocal) {
329 		unsigned long tls;
330 
331 		tls = read_c0_userlocal();
332 		if (tls != current_thread_info()->tp_value)
333 			printk("*HwTLS: %0*lx\n", field, tls);
334 	}
335 
336 	show_stacktrace(current, regs);
337 	show_code((unsigned int __user *) regs->cp0_epc);
338 	printk("\n");
339 }
340 
341 static DEFINE_SPINLOCK(die_lock);
342 
343 void __noreturn die(const char * str, const struct pt_regs * regs)
344 {
345 	static int die_counter;
346 #ifdef CONFIG_MIPS_MT_SMTC
347 	unsigned long dvpret = dvpe();
348 #endif /* CONFIG_MIPS_MT_SMTC */
349 
350 	console_verbose();
351 	spin_lock_irq(&die_lock);
352 	bust_spinlocks(1);
353 #ifdef CONFIG_MIPS_MT_SMTC
354 	mips_mt_regdump(dvpret);
355 #endif /* CONFIG_MIPS_MT_SMTC */
356 	printk("%s[#%d]:\n", str, ++die_counter);
357 	show_registers(regs);
358 	add_taint(TAINT_DIE);
359 	spin_unlock_irq(&die_lock);
360 
361 	if (in_interrupt())
362 		panic("Fatal exception in interrupt");
363 
364 	if (panic_on_oops) {
365 		printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
366 		ssleep(5);
367 		panic("Fatal exception");
368 	}
369 
370 	do_exit(SIGSEGV);
371 }
372 
373 extern const struct exception_table_entry __start___dbe_table[];
374 extern const struct exception_table_entry __stop___dbe_table[];
375 
376 __asm__(
377 "	.section	__dbe_table, \"a\"\n"
378 "	.previous			\n");
379 
380 /* Given an address, look for it in the exception tables. */
381 static const struct exception_table_entry *search_dbe_tables(unsigned long addr)
382 {
383 	const struct exception_table_entry *e;
384 
385 	e = search_extable(__start___dbe_table, __stop___dbe_table - 1, addr);
386 	if (!e)
387 		e = search_module_dbetables(addr);
388 	return e;
389 }
390 
391 asmlinkage void do_be(struct pt_regs *regs)
392 {
393 	const int field = 2 * sizeof(unsigned long);
394 	const struct exception_table_entry *fixup = NULL;
395 	int data = regs->cp0_cause & 4;
396 	int action = MIPS_BE_FATAL;
397 
398 	/* XXX For now.  Fixme, this searches the wrong table ...  */
399 	if (data && !user_mode(regs))
400 		fixup = search_dbe_tables(exception_epc(regs));
401 
402 	if (fixup)
403 		action = MIPS_BE_FIXUP;
404 
405 	if (board_be_handler)
406 		action = board_be_handler(regs, fixup != NULL);
407 
408 	switch (action) {
409 	case MIPS_BE_DISCARD:
410 		return;
411 	case MIPS_BE_FIXUP:
412 		if (fixup) {
413 			regs->cp0_epc = fixup->nextinsn;
414 			return;
415 		}
416 		break;
417 	default:
418 		break;
419 	}
420 
421 	/*
422 	 * Assume it would be too dangerous to continue ...
423 	 */
424 	printk(KERN_ALERT "%s bus error, epc == %0*lx, ra == %0*lx\n",
425 	       data ? "Data" : "Instruction",
426 	       field, regs->cp0_epc, field, regs->regs[31]);
427 	die_if_kernel("Oops", regs);
428 	force_sig(SIGBUS, current);
429 }
430 
431 /*
432  * ll/sc, rdhwr, sync emulation
433  */
434 
435 #define OPCODE 0xfc000000
436 #define BASE   0x03e00000
437 #define RT     0x001f0000
438 #define OFFSET 0x0000ffff
439 #define LL     0xc0000000
440 #define SC     0xe0000000
441 #define SPEC0  0x00000000
442 #define SPEC3  0x7c000000
443 #define RD     0x0000f800
444 #define FUNC   0x0000003f
445 #define SYNC   0x0000000f
446 #define RDHWR  0x0000003b
447 
448 /*
449  * The ll_bit is cleared by r*_switch.S
450  */
451 
452 unsigned long ll_bit;
453 
454 static struct task_struct *ll_task = NULL;
455 
456 static inline int simulate_ll(struct pt_regs *regs, unsigned int opcode)
457 {
458 	unsigned long value, __user *vaddr;
459 	long offset;
460 
461 	/*
462 	 * analyse the ll instruction that just caused a ri exception
463 	 * and put the referenced address to addr.
464 	 */
465 
466 	/* sign extend offset */
467 	offset = opcode & OFFSET;
468 	offset <<= 16;
469 	offset >>= 16;
470 
471 	vaddr = (unsigned long __user *)
472 	        ((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
473 
474 	if ((unsigned long)vaddr & 3)
475 		return SIGBUS;
476 	if (get_user(value, vaddr))
477 		return SIGSEGV;
478 
479 	preempt_disable();
480 
481 	if (ll_task == NULL || ll_task == current) {
482 		ll_bit = 1;
483 	} else {
484 		ll_bit = 0;
485 	}
486 	ll_task = current;
487 
488 	preempt_enable();
489 
490 	regs->regs[(opcode & RT) >> 16] = value;
491 
492 	return 0;
493 }
494 
495 static inline int simulate_sc(struct pt_regs *regs, unsigned int opcode)
496 {
497 	unsigned long __user *vaddr;
498 	unsigned long reg;
499 	long offset;
500 
501 	/*
502 	 * analyse the sc instruction that just caused a ri exception
503 	 * and put the referenced address to addr.
504 	 */
505 
506 	/* sign extend offset */
507 	offset = opcode & OFFSET;
508 	offset <<= 16;
509 	offset >>= 16;
510 
511 	vaddr = (unsigned long __user *)
512 	        ((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
513 	reg = (opcode & RT) >> 16;
514 
515 	if ((unsigned long)vaddr & 3)
516 		return SIGBUS;
517 
518 	preempt_disable();
519 
520 	if (ll_bit == 0 || ll_task != current) {
521 		regs->regs[reg] = 0;
522 		preempt_enable();
523 		return 0;
524 	}
525 
526 	preempt_enable();
527 
528 	if (put_user(regs->regs[reg], vaddr))
529 		return SIGSEGV;
530 
531 	regs->regs[reg] = 1;
532 
533 	return 0;
534 }
535 
536 /*
537  * ll uses the opcode of lwc0 and sc uses the opcode of swc0.  That is both
538  * opcodes are supposed to result in coprocessor unusable exceptions if
539  * executed on ll/sc-less processors.  That's the theory.  In practice a
540  * few processors such as NEC's VR4100 throw reserved instruction exceptions
541  * instead, so we're doing the emulation thing in both exception handlers.
542  */
543 static int simulate_llsc(struct pt_regs *regs, unsigned int opcode)
544 {
545 	if ((opcode & OPCODE) == LL)
546 		return simulate_ll(regs, opcode);
547 	if ((opcode & OPCODE) == SC)
548 		return simulate_sc(regs, opcode);
549 
550 	return -1;			/* Must be something else ... */
551 }
552 
553 /*
554  * Simulate trapping 'rdhwr' instructions to provide user accessible
555  * registers not implemented in hardware.
556  */
557 static int simulate_rdhwr(struct pt_regs *regs, unsigned int opcode)
558 {
559 	struct thread_info *ti = task_thread_info(current);
560 
561 	if ((opcode & OPCODE) == SPEC3 && (opcode & FUNC) == RDHWR) {
562 		int rd = (opcode & RD) >> 11;
563 		int rt = (opcode & RT) >> 16;
564 		switch (rd) {
565 		case 0:		/* CPU number */
566 			regs->regs[rt] = smp_processor_id();
567 			return 0;
568 		case 1:		/* SYNCI length */
569 			regs->regs[rt] = min(current_cpu_data.dcache.linesz,
570 					     current_cpu_data.icache.linesz);
571 			return 0;
572 		case 2:		/* Read count register */
573 			regs->regs[rt] = read_c0_count();
574 			return 0;
575 		case 3:		/* Count register resolution */
576 			switch (current_cpu_data.cputype) {
577 			case CPU_20KC:
578 			case CPU_25KF:
579 				regs->regs[rt] = 1;
580 				break;
581 			default:
582 				regs->regs[rt] = 2;
583 			}
584 			return 0;
585 		case 29:
586 			regs->regs[rt] = ti->tp_value;
587 			return 0;
588 		default:
589 			return -1;
590 		}
591 	}
592 
593 	/* Not ours.  */
594 	return -1;
595 }
596 
597 static int simulate_sync(struct pt_regs *regs, unsigned int opcode)
598 {
599 	if ((opcode & OPCODE) == SPEC0 && (opcode & FUNC) == SYNC)
600 		return 0;
601 
602 	return -1;			/* Must be something else ... */
603 }
604 
605 asmlinkage void do_ov(struct pt_regs *regs)
606 {
607 	siginfo_t info;
608 
609 	die_if_kernel("Integer overflow", regs);
610 
611 	info.si_code = FPE_INTOVF;
612 	info.si_signo = SIGFPE;
613 	info.si_errno = 0;
614 	info.si_addr = (void __user *) regs->cp0_epc;
615 	force_sig_info(SIGFPE, &info, current);
616 }
617 
618 /*
619  * XXX Delayed fp exceptions when doing a lazy ctx switch XXX
620  */
621 asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
622 {
623 	siginfo_t info;
624 
625 	die_if_kernel("FP exception in kernel code", regs);
626 
627 	if (fcr31 & FPU_CSR_UNI_X) {
628 		int sig;
629 
630 		/*
631 		 * Unimplemented operation exception.  If we've got the full
632 		 * software emulator on-board, let's use it...
633 		 *
634 		 * Force FPU to dump state into task/thread context.  We're
635 		 * moving a lot of data here for what is probably a single
636 		 * instruction, but the alternative is to pre-decode the FP
637 		 * register operands before invoking the emulator, which seems
638 		 * a bit extreme for what should be an infrequent event.
639 		 */
640 		/* Ensure 'resume' not overwrite saved fp context again. */
641 		lose_fpu(1);
642 
643 		/* Run the emulator */
644 		sig = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1);
645 
646 		/*
647 		 * We can't allow the emulated instruction to leave any of
648 		 * the cause bit set in $fcr31.
649 		 */
650 		current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
651 
652 		/* Restore the hardware register state */
653 		own_fpu(1);	/* Using the FPU again.  */
654 
655 		/* If something went wrong, signal */
656 		if (sig)
657 			force_sig(sig, current);
658 
659 		return;
660 	} else if (fcr31 & FPU_CSR_INV_X)
661 		info.si_code = FPE_FLTINV;
662 	else if (fcr31 & FPU_CSR_DIV_X)
663 		info.si_code = FPE_FLTDIV;
664 	else if (fcr31 & FPU_CSR_OVF_X)
665 		info.si_code = FPE_FLTOVF;
666 	else if (fcr31 & FPU_CSR_UDF_X)
667 		info.si_code = FPE_FLTUND;
668 	else if (fcr31 & FPU_CSR_INE_X)
669 		info.si_code = FPE_FLTRES;
670 	else
671 		info.si_code = __SI_FAULT;
672 	info.si_signo = SIGFPE;
673 	info.si_errno = 0;
674 	info.si_addr = (void __user *) regs->cp0_epc;
675 	force_sig_info(SIGFPE, &info, current);
676 }
677 
678 static void do_trap_or_bp(struct pt_regs *regs, unsigned int code,
679 	const char *str)
680 {
681 	siginfo_t info;
682 	char b[40];
683 
684 	/*
685 	 * A short test says that IRIX 5.3 sends SIGTRAP for all trap
686 	 * insns, even for trap and break codes that indicate arithmetic
687 	 * failures.  Weird ...
688 	 * But should we continue the brokenness???  --macro
689 	 */
690 	switch (code) {
691 	case BRK_OVERFLOW:
692 	case BRK_DIVZERO:
693 		scnprintf(b, sizeof(b), "%s instruction in kernel code", str);
694 		die_if_kernel(b, regs);
695 		if (code == BRK_DIVZERO)
696 			info.si_code = FPE_INTDIV;
697 		else
698 			info.si_code = FPE_INTOVF;
699 		info.si_signo = SIGFPE;
700 		info.si_errno = 0;
701 		info.si_addr = (void __user *) regs->cp0_epc;
702 		force_sig_info(SIGFPE, &info, current);
703 		break;
704 	case BRK_BUG:
705 		die_if_kernel("Kernel bug detected", regs);
706 		force_sig(SIGTRAP, current);
707 		break;
708 	default:
709 		scnprintf(b, sizeof(b), "%s instruction in kernel code", str);
710 		die_if_kernel(b, regs);
711 		force_sig(SIGTRAP, current);
712 	}
713 }
714 
715 asmlinkage void do_bp(struct pt_regs *regs)
716 {
717 	unsigned int opcode, bcode;
718 
719 	if (__get_user(opcode, (unsigned int __user *) exception_epc(regs)))
720 		goto out_sigsegv;
721 
722 	/*
723 	 * There is the ancient bug in the MIPS assemblers that the break
724 	 * code starts left to bit 16 instead to bit 6 in the opcode.
725 	 * Gas is bug-compatible, but not always, grrr...
726 	 * We handle both cases with a simple heuristics.  --macro
727 	 */
728 	bcode = ((opcode >> 6) & ((1 << 20) - 1));
729 	if (bcode >= (1 << 10))
730 		bcode >>= 10;
731 
732 	do_trap_or_bp(regs, bcode, "Break");
733 	return;
734 
735 out_sigsegv:
736 	force_sig(SIGSEGV, current);
737 }
738 
739 asmlinkage void do_tr(struct pt_regs *regs)
740 {
741 	unsigned int opcode, tcode = 0;
742 
743 	if (__get_user(opcode, (unsigned int __user *) exception_epc(regs)))
744 		goto out_sigsegv;
745 
746 	/* Immediate versions don't provide a code.  */
747 	if (!(opcode & OPCODE))
748 		tcode = ((opcode >> 6) & ((1 << 10) - 1));
749 
750 	do_trap_or_bp(regs, tcode, "Trap");
751 	return;
752 
753 out_sigsegv:
754 	force_sig(SIGSEGV, current);
755 }
756 
757 asmlinkage void do_ri(struct pt_regs *regs)
758 {
759 	unsigned int __user *epc = (unsigned int __user *)exception_epc(regs);
760 	unsigned long old_epc = regs->cp0_epc;
761 	unsigned int opcode = 0;
762 	int status = -1;
763 
764 	die_if_kernel("Reserved instruction in kernel code", regs);
765 
766 	if (unlikely(compute_return_epc(regs) < 0))
767 		return;
768 
769 	if (unlikely(get_user(opcode, epc) < 0))
770 		status = SIGSEGV;
771 
772 	if (!cpu_has_llsc && status < 0)
773 		status = simulate_llsc(regs, opcode);
774 
775 	if (status < 0)
776 		status = simulate_rdhwr(regs, opcode);
777 
778 	if (status < 0)
779 		status = simulate_sync(regs, opcode);
780 
781 	if (status < 0)
782 		status = SIGILL;
783 
784 	if (unlikely(status > 0)) {
785 		regs->cp0_epc = old_epc;		/* Undo skip-over.  */
786 		force_sig(status, current);
787 	}
788 }
789 
790 /*
791  * MIPS MT processors may have fewer FPU contexts than CPU threads. If we've
792  * emulated more than some threshold number of instructions, force migration to
793  * a "CPU" that has FP support.
794  */
795 static void mt_ase_fp_affinity(void)
796 {
797 #ifdef CONFIG_MIPS_MT_FPAFF
798 	if (mt_fpemul_threshold > 0 &&
799 	     ((current->thread.emulated_fp++ > mt_fpemul_threshold))) {
800 		/*
801 		 * If there's no FPU present, or if the application has already
802 		 * restricted the allowed set to exclude any CPUs with FPUs,
803 		 * we'll skip the procedure.
804 		 */
805 		if (cpus_intersects(current->cpus_allowed, mt_fpu_cpumask)) {
806 			cpumask_t tmask;
807 
808 			cpus_and(tmask, current->thread.user_cpus_allowed,
809 			         mt_fpu_cpumask);
810 			set_cpus_allowed(current, tmask);
811 			set_thread_flag(TIF_FPUBOUND);
812 		}
813 	}
814 #endif /* CONFIG_MIPS_MT_FPAFF */
815 }
816 
817 asmlinkage void do_cpu(struct pt_regs *regs)
818 {
819 	unsigned int __user *epc;
820 	unsigned long old_epc;
821 	unsigned int opcode;
822 	unsigned int cpid;
823 	int status;
824 
825 	die_if_kernel("do_cpu invoked from kernel context!", regs);
826 
827 	cpid = (regs->cp0_cause >> CAUSEB_CE) & 3;
828 
829 	switch (cpid) {
830 	case 0:
831 		epc = (unsigned int __user *)exception_epc(regs);
832 		old_epc = regs->cp0_epc;
833 		opcode = 0;
834 		status = -1;
835 
836 		if (unlikely(compute_return_epc(regs) < 0))
837 			return;
838 
839 		if (unlikely(get_user(opcode, epc) < 0))
840 			status = SIGSEGV;
841 
842 		if (!cpu_has_llsc && status < 0)
843 			status = simulate_llsc(regs, opcode);
844 
845 		if (status < 0)
846 			status = simulate_rdhwr(regs, opcode);
847 
848 		if (status < 0)
849 			status = SIGILL;
850 
851 		if (unlikely(status > 0)) {
852 			regs->cp0_epc = old_epc;	/* Undo skip-over.  */
853 			force_sig(status, current);
854 		}
855 
856 		return;
857 
858 	case 1:
859 		if (used_math())	/* Using the FPU again.  */
860 			own_fpu(1);
861 		else {			/* First time FPU user.  */
862 			init_fpu();
863 			set_used_math();
864 		}
865 
866 		if (!raw_cpu_has_fpu) {
867 			int sig;
868 			sig = fpu_emulator_cop1Handler(regs,
869 						&current->thread.fpu, 0);
870 			if (sig)
871 				force_sig(sig, current);
872 			else
873 				mt_ase_fp_affinity();
874 		}
875 
876 		return;
877 
878 	case 2:
879 	case 3:
880 		break;
881 	}
882 
883 	force_sig(SIGILL, current);
884 }
885 
886 asmlinkage void do_mdmx(struct pt_regs *regs)
887 {
888 	force_sig(SIGILL, current);
889 }
890 
891 asmlinkage void do_watch(struct pt_regs *regs)
892 {
893 	if (board_watchpoint_handler) {
894 		(*board_watchpoint_handler)(regs);
895 		return;
896 	}
897 
898 	/*
899 	 * We use the watch exception where available to detect stack
900 	 * overflows.
901 	 */
902 	dump_tlb_all();
903 	show_regs(regs);
904 	panic("Caught WATCH exception - probably caused by stack overflow.");
905 }
906 
907 asmlinkage void do_mcheck(struct pt_regs *regs)
908 {
909 	const int field = 2 * sizeof(unsigned long);
910 	int multi_match = regs->cp0_status & ST0_TS;
911 
912 	show_regs(regs);
913 
914 	if (multi_match) {
915 		printk("Index   : %0x\n", read_c0_index());
916 		printk("Pagemask: %0x\n", read_c0_pagemask());
917 		printk("EntryHi : %0*lx\n", field, read_c0_entryhi());
918 		printk("EntryLo0: %0*lx\n", field, read_c0_entrylo0());
919 		printk("EntryLo1: %0*lx\n", field, read_c0_entrylo1());
920 		printk("\n");
921 		dump_tlb_all();
922 	}
923 
924 	show_code((unsigned int __user *) regs->cp0_epc);
925 
926 	/*
927 	 * Some chips may have other causes of machine check (e.g. SB1
928 	 * graduation timer)
929 	 */
930 	panic("Caught Machine Check exception - %scaused by multiple "
931 	      "matching entries in the TLB.",
932 	      (multi_match) ? "" : "not ");
933 }
934 
935 asmlinkage void do_mt(struct pt_regs *regs)
936 {
937 	int subcode;
938 
939 	subcode = (read_vpe_c0_vpecontrol() & VPECONTROL_EXCPT)
940 			>> VPECONTROL_EXCPT_SHIFT;
941 	switch (subcode) {
942 	case 0:
943 		printk(KERN_DEBUG "Thread Underflow\n");
944 		break;
945 	case 1:
946 		printk(KERN_DEBUG "Thread Overflow\n");
947 		break;
948 	case 2:
949 		printk(KERN_DEBUG "Invalid YIELD Qualifier\n");
950 		break;
951 	case 3:
952 		printk(KERN_DEBUG "Gating Storage Exception\n");
953 		break;
954 	case 4:
955 		printk(KERN_DEBUG "YIELD Scheduler Exception\n");
956 		break;
957 	case 5:
958 		printk(KERN_DEBUG "Gating Storage Schedulier Exception\n");
959 		break;
960 	default:
961 		printk(KERN_DEBUG "*** UNKNOWN THREAD EXCEPTION %d ***\n",
962 			subcode);
963 		break;
964 	}
965 	die_if_kernel("MIPS MT Thread exception in kernel", regs);
966 
967 	force_sig(SIGILL, current);
968 }
969 
970 
971 asmlinkage void do_dsp(struct pt_regs *regs)
972 {
973 	if (cpu_has_dsp)
974 		panic("Unexpected DSP exception\n");
975 
976 	force_sig(SIGILL, current);
977 }
978 
979 asmlinkage void do_reserved(struct pt_regs *regs)
980 {
981 	/*
982 	 * Game over - no way to handle this if it ever occurs.  Most probably
983 	 * caused by a new unknown cpu type or after another deadly
984 	 * hard/software error.
985 	 */
986 	show_regs(regs);
987 	panic("Caught reserved exception %ld - should not happen.",
988 	      (regs->cp0_cause & 0x7f) >> 2);
989 }
990 
991 static int __initdata l1parity = 1;
992 static int __init nol1parity(char *s)
993 {
994 	l1parity = 0;
995 	return 1;
996 }
997 __setup("nol1par", nol1parity);
998 static int __initdata l2parity = 1;
999 static int __init nol2parity(char *s)
1000 {
1001 	l2parity = 0;
1002 	return 1;
1003 }
1004 __setup("nol2par", nol2parity);
1005 
1006 /*
1007  * Some MIPS CPUs can enable/disable for cache parity detection, but do
1008  * it different ways.
1009  */
1010 static inline void parity_protection_init(void)
1011 {
1012 	switch (current_cpu_type()) {
1013 	case CPU_24K:
1014 	case CPU_34K:
1015 	case CPU_74K:
1016 	case CPU_1004K:
1017 		{
1018 #define ERRCTL_PE	0x80000000
1019 #define ERRCTL_L2P	0x00800000
1020 			unsigned long errctl;
1021 			unsigned int l1parity_present, l2parity_present;
1022 
1023 			errctl = read_c0_ecc();
1024 			errctl &= ~(ERRCTL_PE|ERRCTL_L2P);
1025 
1026 			/* probe L1 parity support */
1027 			write_c0_ecc(errctl | ERRCTL_PE);
1028 			back_to_back_c0_hazard();
1029 			l1parity_present = (read_c0_ecc() & ERRCTL_PE);
1030 
1031 			/* probe L2 parity support */
1032 			write_c0_ecc(errctl|ERRCTL_L2P);
1033 			back_to_back_c0_hazard();
1034 			l2parity_present = (read_c0_ecc() & ERRCTL_L2P);
1035 
1036 			if (l1parity_present && l2parity_present) {
1037 				if (l1parity)
1038 					errctl |= ERRCTL_PE;
1039 				if (l1parity ^ l2parity)
1040 					errctl |= ERRCTL_L2P;
1041 			} else if (l1parity_present) {
1042 				if (l1parity)
1043 					errctl |= ERRCTL_PE;
1044 			} else if (l2parity_present) {
1045 				if (l2parity)
1046 					errctl |= ERRCTL_L2P;
1047 			} else {
1048 				/* No parity available */
1049 			}
1050 
1051 			printk(KERN_INFO "Writing ErrCtl register=%08lx\n", errctl);
1052 
1053 			write_c0_ecc(errctl);
1054 			back_to_back_c0_hazard();
1055 			errctl = read_c0_ecc();
1056 			printk(KERN_INFO "Readback ErrCtl register=%08lx\n", errctl);
1057 
1058 			if (l1parity_present)
1059 				printk(KERN_INFO "Cache parity protection %sabled\n",
1060 				       (errctl & ERRCTL_PE) ? "en" : "dis");
1061 
1062 			if (l2parity_present) {
1063 				if (l1parity_present && l1parity)
1064 					errctl ^= ERRCTL_L2P;
1065 				printk(KERN_INFO "L2 cache parity protection %sabled\n",
1066 				       (errctl & ERRCTL_L2P) ? "en" : "dis");
1067 			}
1068 		}
1069 		break;
1070 
1071 	case CPU_5KC:
1072 		write_c0_ecc(0x80000000);
1073 		back_to_back_c0_hazard();
1074 		/* Set the PE bit (bit 31) in the c0_errctl register. */
1075 		printk(KERN_INFO "Cache parity protection %sabled\n",
1076 		       (read_c0_ecc() & 0x80000000) ? "en" : "dis");
1077 		break;
1078 	case CPU_20KC:
1079 	case CPU_25KF:
1080 		/* Clear the DE bit (bit 16) in the c0_status register. */
1081 		printk(KERN_INFO "Enable cache parity protection for "
1082 		       "MIPS 20KC/25KF CPUs.\n");
1083 		clear_c0_status(ST0_DE);
1084 		break;
1085 	default:
1086 		break;
1087 	}
1088 }
1089 
1090 asmlinkage void cache_parity_error(void)
1091 {
1092 	const int field = 2 * sizeof(unsigned long);
1093 	unsigned int reg_val;
1094 
1095 	/* For the moment, report the problem and hang. */
1096 	printk("Cache error exception:\n");
1097 	printk("cp0_errorepc == %0*lx\n", field, read_c0_errorepc());
1098 	reg_val = read_c0_cacheerr();
1099 	printk("c0_cacheerr == %08x\n", reg_val);
1100 
1101 	printk("Decoded c0_cacheerr: %s cache fault in %s reference.\n",
1102 	       reg_val & (1<<30) ? "secondary" : "primary",
1103 	       reg_val & (1<<31) ? "data" : "insn");
1104 	printk("Error bits: %s%s%s%s%s%s%s\n",
1105 	       reg_val & (1<<29) ? "ED " : "",
1106 	       reg_val & (1<<28) ? "ET " : "",
1107 	       reg_val & (1<<26) ? "EE " : "",
1108 	       reg_val & (1<<25) ? "EB " : "",
1109 	       reg_val & (1<<24) ? "EI " : "",
1110 	       reg_val & (1<<23) ? "E1 " : "",
1111 	       reg_val & (1<<22) ? "E0 " : "");
1112 	printk("IDX: 0x%08x\n", reg_val & ((1<<22)-1));
1113 
1114 #if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
1115 	if (reg_val & (1<<22))
1116 		printk("DErrAddr0: 0x%0*lx\n", field, read_c0_derraddr0());
1117 
1118 	if (reg_val & (1<<23))
1119 		printk("DErrAddr1: 0x%0*lx\n", field, read_c0_derraddr1());
1120 #endif
1121 
1122 	panic("Can't handle the cache error!");
1123 }
1124 
1125 /*
1126  * SDBBP EJTAG debug exception handler.
1127  * We skip the instruction and return to the next instruction.
1128  */
1129 void ejtag_exception_handler(struct pt_regs *regs)
1130 {
1131 	const int field = 2 * sizeof(unsigned long);
1132 	unsigned long depc, old_epc;
1133 	unsigned int debug;
1134 
1135 	printk(KERN_DEBUG "SDBBP EJTAG debug exception - not handled yet, just ignored!\n");
1136 	depc = read_c0_depc();
1137 	debug = read_c0_debug();
1138 	printk(KERN_DEBUG "c0_depc = %0*lx, DEBUG = %08x\n", field, depc, debug);
1139 	if (debug & 0x80000000) {
1140 		/*
1141 		 * In branch delay slot.
1142 		 * We cheat a little bit here and use EPC to calculate the
1143 		 * debug return address (DEPC). EPC is restored after the
1144 		 * calculation.
1145 		 */
1146 		old_epc = regs->cp0_epc;
1147 		regs->cp0_epc = depc;
1148 		__compute_return_epc(regs);
1149 		depc = regs->cp0_epc;
1150 		regs->cp0_epc = old_epc;
1151 	} else
1152 		depc += 4;
1153 	write_c0_depc(depc);
1154 
1155 #if 0
1156 	printk(KERN_DEBUG "\n\n----- Enable EJTAG single stepping ----\n\n");
1157 	write_c0_debug(debug | 0x100);
1158 #endif
1159 }
1160 
1161 /*
1162  * NMI exception handler.
1163  */
1164 NORET_TYPE void ATTRIB_NORET nmi_exception_handler(struct pt_regs *regs)
1165 {
1166 	bust_spinlocks(1);
1167 	printk("NMI taken!!!!\n");
1168 	die("NMI", regs);
1169 }
1170 
1171 #define VECTORSPACING 0x100	/* for EI/VI mode */
1172 
1173 unsigned long ebase;
1174 unsigned long exception_handlers[32];
1175 unsigned long vi_handlers[64];
1176 
1177 /*
1178  * As a side effect of the way this is implemented we're limited
1179  * to interrupt handlers in the address range from
1180  * KSEG0 <= x < KSEG0 + 256mb on the Nevada.  Oh well ...
1181  */
1182 void *set_except_vector(int n, void *addr)
1183 {
1184 	unsigned long handler = (unsigned long) addr;
1185 	unsigned long old_handler = exception_handlers[n];
1186 
1187 	exception_handlers[n] = handler;
1188 	if (n == 0 && cpu_has_divec) {
1189 		*(u32 *)(ebase + 0x200) = 0x08000000 |
1190 					  (0x03ffffff & (handler >> 2));
1191 		flush_icache_range(ebase + 0x200, ebase + 0x204);
1192 	}
1193 	return (void *)old_handler;
1194 }
1195 
1196 static asmlinkage void do_default_vi(void)
1197 {
1198 	show_regs(get_irq_regs());
1199 	panic("Caught unexpected vectored interrupt.");
1200 }
1201 
1202 static void *set_vi_srs_handler(int n, vi_handler_t addr, int srs)
1203 {
1204 	unsigned long handler;
1205 	unsigned long old_handler = vi_handlers[n];
1206 	int srssets = current_cpu_data.srsets;
1207 	u32 *w;
1208 	unsigned char *b;
1209 
1210 	if (!cpu_has_veic && !cpu_has_vint)
1211 		BUG();
1212 
1213 	if (addr == NULL) {
1214 		handler = (unsigned long) do_default_vi;
1215 		srs = 0;
1216 	} else
1217 		handler = (unsigned long) addr;
1218 	vi_handlers[n] = (unsigned long) addr;
1219 
1220 	b = (unsigned char *)(ebase + 0x200 + n*VECTORSPACING);
1221 
1222 	if (srs >= srssets)
1223 		panic("Shadow register set %d not supported", srs);
1224 
1225 	if (cpu_has_veic) {
1226 		if (board_bind_eic_interrupt)
1227 			board_bind_eic_interrupt(n, srs);
1228 	} else if (cpu_has_vint) {
1229 		/* SRSMap is only defined if shadow sets are implemented */
1230 		if (srssets > 1)
1231 			change_c0_srsmap(0xf << n*4, srs << n*4);
1232 	}
1233 
1234 	if (srs == 0) {
1235 		/*
1236 		 * If no shadow set is selected then use the default handler
1237 		 * that does normal register saving and a standard interrupt exit
1238 		 */
1239 
1240 		extern char except_vec_vi, except_vec_vi_lui;
1241 		extern char except_vec_vi_ori, except_vec_vi_end;
1242 #ifdef CONFIG_MIPS_MT_SMTC
1243 		/*
1244 		 * We need to provide the SMTC vectored interrupt handler
1245 		 * not only with the address of the handler, but with the
1246 		 * Status.IM bit to be masked before going there.
1247 		 */
1248 		extern char except_vec_vi_mori;
1249 		const int mori_offset = &except_vec_vi_mori - &except_vec_vi;
1250 #endif /* CONFIG_MIPS_MT_SMTC */
1251 		const int handler_len = &except_vec_vi_end - &except_vec_vi;
1252 		const int lui_offset = &except_vec_vi_lui - &except_vec_vi;
1253 		const int ori_offset = &except_vec_vi_ori - &except_vec_vi;
1254 
1255 		if (handler_len > VECTORSPACING) {
1256 			/*
1257 			 * Sigh... panicing won't help as the console
1258 			 * is probably not configured :(
1259 			 */
1260 			panic("VECTORSPACING too small");
1261 		}
1262 
1263 		memcpy(b, &except_vec_vi, handler_len);
1264 #ifdef CONFIG_MIPS_MT_SMTC
1265 		BUG_ON(n > 7);	/* Vector index %d exceeds SMTC maximum. */
1266 
1267 		w = (u32 *)(b + mori_offset);
1268 		*w = (*w & 0xffff0000) | (0x100 << n);
1269 #endif /* CONFIG_MIPS_MT_SMTC */
1270 		w = (u32 *)(b + lui_offset);
1271 		*w = (*w & 0xffff0000) | (((u32)handler >> 16) & 0xffff);
1272 		w = (u32 *)(b + ori_offset);
1273 		*w = (*w & 0xffff0000) | ((u32)handler & 0xffff);
1274 		flush_icache_range((unsigned long)b, (unsigned long)(b+handler_len));
1275 	}
1276 	else {
1277 		/*
1278 		 * In other cases jump directly to the interrupt handler
1279 		 *
1280 		 * It is the handlers responsibility to save registers if required
1281 		 * (eg hi/lo) and return from the exception using "eret"
1282 		 */
1283 		w = (u32 *)b;
1284 		*w++ = 0x08000000 | (((u32)handler >> 2) & 0x03fffff); /* j handler */
1285 		*w = 0;
1286 		flush_icache_range((unsigned long)b, (unsigned long)(b+8));
1287 	}
1288 
1289 	return (void *)old_handler;
1290 }
1291 
1292 void *set_vi_handler(int n, vi_handler_t addr)
1293 {
1294 	return set_vi_srs_handler(n, addr, 0);
1295 }
1296 
1297 /*
1298  * This is used by native signal handling
1299  */
1300 asmlinkage int (*save_fp_context)(struct sigcontext __user *sc);
1301 asmlinkage int (*restore_fp_context)(struct sigcontext __user *sc);
1302 
1303 extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
1304 extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
1305 
1306 extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc);
1307 extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc);
1308 
1309 #ifdef CONFIG_SMP
1310 static int smp_save_fp_context(struct sigcontext __user *sc)
1311 {
1312 	return raw_cpu_has_fpu
1313 	       ? _save_fp_context(sc)
1314 	       : fpu_emulator_save_context(sc);
1315 }
1316 
1317 static int smp_restore_fp_context(struct sigcontext __user *sc)
1318 {
1319 	return raw_cpu_has_fpu
1320 	       ? _restore_fp_context(sc)
1321 	       : fpu_emulator_restore_context(sc);
1322 }
1323 #endif
1324 
1325 static inline void signal_init(void)
1326 {
1327 #ifdef CONFIG_SMP
1328 	/* For now just do the cpu_has_fpu check when the functions are invoked */
1329 	save_fp_context = smp_save_fp_context;
1330 	restore_fp_context = smp_restore_fp_context;
1331 #else
1332 	if (cpu_has_fpu) {
1333 		save_fp_context = _save_fp_context;
1334 		restore_fp_context = _restore_fp_context;
1335 	} else {
1336 		save_fp_context = fpu_emulator_save_context;
1337 		restore_fp_context = fpu_emulator_restore_context;
1338 	}
1339 #endif
1340 }
1341 
1342 #ifdef CONFIG_MIPS32_COMPAT
1343 
1344 /*
1345  * This is used by 32-bit signal stuff on the 64-bit kernel
1346  */
1347 asmlinkage int (*save_fp_context32)(struct sigcontext32 __user *sc);
1348 asmlinkage int (*restore_fp_context32)(struct sigcontext32 __user *sc);
1349 
1350 extern asmlinkage int _save_fp_context32(struct sigcontext32 __user *sc);
1351 extern asmlinkage int _restore_fp_context32(struct sigcontext32 __user *sc);
1352 
1353 extern asmlinkage int fpu_emulator_save_context32(struct sigcontext32 __user *sc);
1354 extern asmlinkage int fpu_emulator_restore_context32(struct sigcontext32 __user *sc);
1355 
1356 static inline void signal32_init(void)
1357 {
1358 	if (cpu_has_fpu) {
1359 		save_fp_context32 = _save_fp_context32;
1360 		restore_fp_context32 = _restore_fp_context32;
1361 	} else {
1362 		save_fp_context32 = fpu_emulator_save_context32;
1363 		restore_fp_context32 = fpu_emulator_restore_context32;
1364 	}
1365 }
1366 #endif
1367 
1368 extern void cpu_cache_init(void);
1369 extern void tlb_init(void);
1370 extern void flush_tlb_handlers(void);
1371 
1372 /*
1373  * Timer interrupt
1374  */
1375 int cp0_compare_irq;
1376 
1377 /*
1378  * Performance counter IRQ or -1 if shared with timer
1379  */
1380 int cp0_perfcount_irq;
1381 EXPORT_SYMBOL_GPL(cp0_perfcount_irq);
1382 
1383 static int __cpuinitdata noulri;
1384 
1385 static int __init ulri_disable(char *s)
1386 {
1387 	pr_info("Disabling ulri\n");
1388 	noulri = 1;
1389 
1390 	return 1;
1391 }
1392 __setup("noulri", ulri_disable);
1393 
1394 void __cpuinit per_cpu_trap_init(void)
1395 {
1396 	unsigned int cpu = smp_processor_id();
1397 	unsigned int status_set = ST0_CU0;
1398 #ifdef CONFIG_MIPS_MT_SMTC
1399 	int secondaryTC = 0;
1400 	int bootTC = (cpu == 0);
1401 
1402 	/*
1403 	 * Only do per_cpu_trap_init() for first TC of Each VPE.
1404 	 * Note that this hack assumes that the SMTC init code
1405 	 * assigns TCs consecutively and in ascending order.
1406 	 */
1407 
1408 	if (((read_c0_tcbind() & TCBIND_CURTC) != 0) &&
1409 	    ((read_c0_tcbind() & TCBIND_CURVPE) == cpu_data[cpu - 1].vpe_id))
1410 		secondaryTC = 1;
1411 #endif /* CONFIG_MIPS_MT_SMTC */
1412 
1413 	/*
1414 	 * Disable coprocessors and select 32-bit or 64-bit addressing
1415 	 * and the 16/32 or 32/32 FPR register model.  Reset the BEV
1416 	 * flag that some firmware may have left set and the TS bit (for
1417 	 * IP27).  Set XX for ISA IV code to work.
1418 	 */
1419 #ifdef CONFIG_64BIT
1420 	status_set |= ST0_FR|ST0_KX|ST0_SX|ST0_UX;
1421 #endif
1422 	if (current_cpu_data.isa_level == MIPS_CPU_ISA_IV)
1423 		status_set |= ST0_XX;
1424 	if (cpu_has_dsp)
1425 		status_set |= ST0_MX;
1426 
1427 	change_c0_status(ST0_CU|ST0_MX|ST0_RE|ST0_FR|ST0_BEV|ST0_TS|ST0_KX|ST0_SX|ST0_UX,
1428 			 status_set);
1429 
1430 	if (cpu_has_mips_r2) {
1431 		unsigned int enable = 0x0000000f;
1432 
1433 		if (!noulri && cpu_has_userlocal)
1434 			enable |= (1 << 29);
1435 
1436 		write_c0_hwrena(enable);
1437 	}
1438 
1439 #ifdef CONFIG_MIPS_MT_SMTC
1440 	if (!secondaryTC) {
1441 #endif /* CONFIG_MIPS_MT_SMTC */
1442 
1443 	if (cpu_has_veic || cpu_has_vint) {
1444 		write_c0_ebase(ebase);
1445 		/* Setting vector spacing enables EI/VI mode  */
1446 		change_c0_intctl(0x3e0, VECTORSPACING);
1447 	}
1448 	if (cpu_has_divec) {
1449 		if (cpu_has_mipsmt) {
1450 			unsigned int vpflags = dvpe();
1451 			set_c0_cause(CAUSEF_IV);
1452 			evpe(vpflags);
1453 		} else
1454 			set_c0_cause(CAUSEF_IV);
1455 	}
1456 
1457 	/*
1458 	 * Before R2 both interrupt numbers were fixed to 7, so on R2 only:
1459 	 *
1460 	 *  o read IntCtl.IPTI to determine the timer interrupt
1461 	 *  o read IntCtl.IPPCI to determine the performance counter interrupt
1462 	 */
1463 	if (cpu_has_mips_r2) {
1464 		cp0_compare_irq = (read_c0_intctl() >> 29) & 7;
1465 		cp0_perfcount_irq = (read_c0_intctl() >> 26) & 7;
1466 		if (cp0_perfcount_irq == cp0_compare_irq)
1467 			cp0_perfcount_irq = -1;
1468 	} else {
1469 		cp0_compare_irq = CP0_LEGACY_COMPARE_IRQ;
1470 		cp0_perfcount_irq = -1;
1471 	}
1472 
1473 #ifdef CONFIG_MIPS_MT_SMTC
1474 	}
1475 #endif /* CONFIG_MIPS_MT_SMTC */
1476 
1477 	cpu_data[cpu].asid_cache = ASID_FIRST_VERSION;
1478 	TLBMISS_HANDLER_SETUP();
1479 
1480 	atomic_inc(&init_mm.mm_count);
1481 	current->active_mm = &init_mm;
1482 	BUG_ON(current->mm);
1483 	enter_lazy_tlb(&init_mm, current);
1484 
1485 #ifdef CONFIG_MIPS_MT_SMTC
1486 	if (bootTC) {
1487 #endif /* CONFIG_MIPS_MT_SMTC */
1488 		cpu_cache_init();
1489 		tlb_init();
1490 #ifdef CONFIG_MIPS_MT_SMTC
1491 	} else if (!secondaryTC) {
1492 		/*
1493 		 * First TC in non-boot VPE must do subset of tlb_init()
1494 		 * for MMU countrol registers.
1495 		 */
1496 		write_c0_pagemask(PM_DEFAULT_MASK);
1497 		write_c0_wired(0);
1498 	}
1499 #endif /* CONFIG_MIPS_MT_SMTC */
1500 }
1501 
1502 /* Install CPU exception handler */
1503 void __init set_handler(unsigned long offset, void *addr, unsigned long size)
1504 {
1505 	memcpy((void *)(ebase + offset), addr, size);
1506 	flush_icache_range(ebase + offset, ebase + offset + size);
1507 }
1508 
1509 static char panic_null_cerr[] __cpuinitdata =
1510 	"Trying to set NULL cache error exception handler";
1511 
1512 /* Install uncached CPU exception handler */
1513 void __cpuinit set_uncached_handler(unsigned long offset, void *addr,
1514 	unsigned long size)
1515 {
1516 #ifdef CONFIG_32BIT
1517 	unsigned long uncached_ebase = KSEG1ADDR(ebase);
1518 #endif
1519 #ifdef CONFIG_64BIT
1520 	unsigned long uncached_ebase = TO_UNCAC(ebase);
1521 #endif
1522 
1523 	if (!addr)
1524 		panic(panic_null_cerr);
1525 
1526 	memcpy((void *)(uncached_ebase + offset), addr, size);
1527 }
1528 
1529 static int __initdata rdhwr_noopt;
1530 static int __init set_rdhwr_noopt(char *str)
1531 {
1532 	rdhwr_noopt = 1;
1533 	return 1;
1534 }
1535 
1536 __setup("rdhwr_noopt", set_rdhwr_noopt);
1537 
1538 void __init trap_init(void)
1539 {
1540 	extern char except_vec3_generic, except_vec3_r4000;
1541 	extern char except_vec4;
1542 	unsigned long i;
1543 
1544 	if (cpu_has_veic || cpu_has_vint)
1545 		ebase = (unsigned long) alloc_bootmem_low_pages(0x200 + VECTORSPACING*64);
1546 	else
1547 		ebase = CAC_BASE;
1548 
1549 	per_cpu_trap_init();
1550 
1551 	/*
1552 	 * Copy the generic exception handlers to their final destination.
1553 	 * This will be overriden later as suitable for a particular
1554 	 * configuration.
1555 	 */
1556 	set_handler(0x180, &except_vec3_generic, 0x80);
1557 
1558 	/*
1559 	 * Setup default vectors
1560 	 */
1561 	for (i = 0; i <= 31; i++)
1562 		set_except_vector(i, handle_reserved);
1563 
1564 	/*
1565 	 * Copy the EJTAG debug exception vector handler code to it's final
1566 	 * destination.
1567 	 */
1568 	if (cpu_has_ejtag && board_ejtag_handler_setup)
1569 		board_ejtag_handler_setup();
1570 
1571 	/*
1572 	 * Only some CPUs have the watch exceptions.
1573 	 */
1574 	if (cpu_has_watch)
1575 		set_except_vector(23, handle_watch);
1576 
1577 	/*
1578 	 * Initialise interrupt handlers
1579 	 */
1580 	if (cpu_has_veic || cpu_has_vint) {
1581 		int nvec = cpu_has_veic ? 64 : 8;
1582 		for (i = 0; i < nvec; i++)
1583 			set_vi_handler(i, NULL);
1584 	}
1585 	else if (cpu_has_divec)
1586 		set_handler(0x200, &except_vec4, 0x8);
1587 
1588 	/*
1589 	 * Some CPUs can enable/disable for cache parity detection, but does
1590 	 * it different ways.
1591 	 */
1592 	parity_protection_init();
1593 
1594 	/*
1595 	 * The Data Bus Errors / Instruction Bus Errors are signaled
1596 	 * by external hardware.  Therefore these two exceptions
1597 	 * may have board specific handlers.
1598 	 */
1599 	if (board_be_init)
1600 		board_be_init();
1601 
1602 	set_except_vector(0, handle_int);
1603 	set_except_vector(1, handle_tlbm);
1604 	set_except_vector(2, handle_tlbl);
1605 	set_except_vector(3, handle_tlbs);
1606 
1607 	set_except_vector(4, handle_adel);
1608 	set_except_vector(5, handle_ades);
1609 
1610 	set_except_vector(6, handle_ibe);
1611 	set_except_vector(7, handle_dbe);
1612 
1613 	set_except_vector(8, handle_sys);
1614 	set_except_vector(9, handle_bp);
1615 	set_except_vector(10, rdhwr_noopt ? handle_ri :
1616 			  (cpu_has_vtag_icache ?
1617 			   handle_ri_rdhwr_vivt : handle_ri_rdhwr));
1618 	set_except_vector(11, handle_cpu);
1619 	set_except_vector(12, handle_ov);
1620 	set_except_vector(13, handle_tr);
1621 
1622 	if (current_cpu_type() == CPU_R6000 ||
1623 	    current_cpu_type() == CPU_R6000A) {
1624 		/*
1625 		 * The R6000 is the only R-series CPU that features a machine
1626 		 * check exception (similar to the R4000 cache error) and
1627 		 * unaligned ldc1/sdc1 exception.  The handlers have not been
1628 		 * written yet.  Well, anyway there is no R6000 machine on the
1629 		 * current list of targets for Linux/MIPS.
1630 		 * (Duh, crap, there is someone with a triple R6k machine)
1631 		 */
1632 		//set_except_vector(14, handle_mc);
1633 		//set_except_vector(15, handle_ndc);
1634 	}
1635 
1636 
1637 	if (board_nmi_handler_setup)
1638 		board_nmi_handler_setup();
1639 
1640 	if (cpu_has_fpu && !cpu_has_nofpuex)
1641 		set_except_vector(15, handle_fpe);
1642 
1643 	set_except_vector(22, handle_mdmx);
1644 
1645 	if (cpu_has_mcheck)
1646 		set_except_vector(24, handle_mcheck);
1647 
1648 	if (cpu_has_mipsmt)
1649 		set_except_vector(25, handle_mt);
1650 
1651 	set_except_vector(26, handle_dsp);
1652 
1653 	if (cpu_has_vce)
1654 		/* Special exception: R4[04]00 uses also the divec space. */
1655 		memcpy((void *)(CAC_BASE + 0x180), &except_vec3_r4000, 0x100);
1656 	else if (cpu_has_4kex)
1657 		memcpy((void *)(CAC_BASE + 0x180), &except_vec3_generic, 0x80);
1658 	else
1659 		memcpy((void *)(CAC_BASE + 0x080), &except_vec3_generic, 0x80);
1660 
1661 	signal_init();
1662 #ifdef CONFIG_MIPS32_COMPAT
1663 	signal32_init();
1664 #endif
1665 
1666 	flush_icache_range(ebase, ebase + 0x400);
1667 	flush_tlb_handlers();
1668 }
1669