xref: /linux/arch/mips/kernel/traps.c (revision a5c4300389bb33ade2515c082709217f0614cf15)
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 #include <linux/kgdb.h>
27 #include <linux/kdebug.h>
28 #include <linux/notifier.h>
29 #include <linux/kdb.h>
30 
31 #include <asm/bootinfo.h>
32 #include <asm/branch.h>
33 #include <asm/break.h>
34 #include <asm/cop2.h>
35 #include <asm/cpu.h>
36 #include <asm/dsp.h>
37 #include <asm/fpu.h>
38 #include <asm/fpu_emulator.h>
39 #include <asm/mipsregs.h>
40 #include <asm/mipsmtregs.h>
41 #include <asm/module.h>
42 #include <asm/pgtable.h>
43 #include <asm/ptrace.h>
44 #include <asm/sections.h>
45 #include <asm/system.h>
46 #include <asm/tlbdebug.h>
47 #include <asm/traps.h>
48 #include <asm/uaccess.h>
49 #include <asm/watch.h>
50 #include <asm/mmu_context.h>
51 #include <asm/types.h>
52 #include <asm/stacktrace.h>
53 #include <asm/irq.h>
54 #include <asm/uasm.h>
55 
56 extern void check_wait(void);
57 extern asmlinkage void r4k_wait(void);
58 extern asmlinkage void rollback_handle_int(void);
59 extern asmlinkage void handle_int(void);
60 extern asmlinkage void handle_tlbm(void);
61 extern asmlinkage void handle_tlbl(void);
62 extern asmlinkage void handle_tlbs(void);
63 extern asmlinkage void handle_adel(void);
64 extern asmlinkage void handle_ades(void);
65 extern asmlinkage void handle_ibe(void);
66 extern asmlinkage void handle_dbe(void);
67 extern asmlinkage void handle_sys(void);
68 extern asmlinkage void handle_bp(void);
69 extern asmlinkage void handle_ri(void);
70 extern asmlinkage void handle_ri_rdhwr_vivt(void);
71 extern asmlinkage void handle_ri_rdhwr(void);
72 extern asmlinkage void handle_cpu(void);
73 extern asmlinkage void handle_ov(void);
74 extern asmlinkage void handle_tr(void);
75 extern asmlinkage void handle_fpe(void);
76 extern asmlinkage void handle_mdmx(void);
77 extern asmlinkage void handle_watch(void);
78 extern asmlinkage void handle_mt(void);
79 extern asmlinkage void handle_dsp(void);
80 extern asmlinkage void handle_mcheck(void);
81 extern asmlinkage void handle_reserved(void);
82 
83 extern int fpu_emulator_cop1Handler(struct pt_regs *xcp,
84 	struct mips_fpu_struct *ctx, int has_fpu);
85 
86 void (*board_be_init)(void);
87 int (*board_be_handler)(struct pt_regs *regs, int is_fixup);
88 void (*board_nmi_handler_setup)(void);
89 void (*board_ejtag_handler_setup)(void);
90 void (*board_bind_eic_interrupt)(int irq, int regset);
91 
92 
93 static void show_raw_backtrace(unsigned long reg29)
94 {
95 	unsigned long *sp = (unsigned long *)(reg29 & ~3);
96 	unsigned long addr;
97 
98 	printk("Call Trace:");
99 #ifdef CONFIG_KALLSYMS
100 	printk("\n");
101 #endif
102 	while (!kstack_end(sp)) {
103 		unsigned long __user *p =
104 			(unsigned long __user *)(unsigned long)sp++;
105 		if (__get_user(addr, p)) {
106 			printk(" (Bad stack address)");
107 			break;
108 		}
109 		if (__kernel_text_address(addr))
110 			print_ip_sym(addr);
111 	}
112 	printk("\n");
113 }
114 
115 #ifdef CONFIG_KALLSYMS
116 int raw_show_trace;
117 static int __init set_raw_show_trace(char *str)
118 {
119 	raw_show_trace = 1;
120 	return 1;
121 }
122 __setup("raw_show_trace", set_raw_show_trace);
123 #endif
124 
125 static void show_backtrace(struct task_struct *task, const struct pt_regs *regs)
126 {
127 	unsigned long sp = regs->regs[29];
128 	unsigned long ra = regs->regs[31];
129 	unsigned long pc = regs->cp0_epc;
130 
131 	if (raw_show_trace || !__kernel_text_address(pc)) {
132 		show_raw_backtrace(sp);
133 		return;
134 	}
135 	printk("Call Trace:\n");
136 	do {
137 		print_ip_sym(pc);
138 		pc = unwind_stack(task, &sp, pc, &ra);
139 	} while (pc);
140 	printk("\n");
141 }
142 
143 /*
144  * This routine abuses get_user()/put_user() to reference pointers
145  * with at least a bit of error checking ...
146  */
147 static void show_stacktrace(struct task_struct *task,
148 	const struct pt_regs *regs)
149 {
150 	const int field = 2 * sizeof(unsigned long);
151 	long stackdata;
152 	int i;
153 	unsigned long __user *sp = (unsigned long __user *)regs->regs[29];
154 
155 	printk("Stack :");
156 	i = 0;
157 	while ((unsigned long) sp & (PAGE_SIZE - 1)) {
158 		if (i && ((i % (64 / field)) == 0))
159 			printk("\n       ");
160 		if (i > 39) {
161 			printk(" ...");
162 			break;
163 		}
164 
165 		if (__get_user(stackdata, sp++)) {
166 			printk(" (Bad stack address)");
167 			break;
168 		}
169 
170 		printk(" %0*lx", field, stackdata);
171 		i++;
172 	}
173 	printk("\n");
174 	show_backtrace(task, regs);
175 }
176 
177 void show_stack(struct task_struct *task, unsigned long *sp)
178 {
179 	struct pt_regs regs;
180 	if (sp) {
181 		regs.regs[29] = (unsigned long)sp;
182 		regs.regs[31] = 0;
183 		regs.cp0_epc = 0;
184 	} else {
185 		if (task && task != current) {
186 			regs.regs[29] = task->thread.reg29;
187 			regs.regs[31] = 0;
188 			regs.cp0_epc = task->thread.reg31;
189 #ifdef CONFIG_KGDB_KDB
190 		} else if (atomic_read(&kgdb_active) != -1 &&
191 			   kdb_current_regs) {
192 			memcpy(&regs, kdb_current_regs, sizeof(regs));
193 #endif /* CONFIG_KGDB_KDB */
194 		} else {
195 			prepare_frametrace(&regs);
196 		}
197 	}
198 	show_stacktrace(task, &regs);
199 }
200 
201 /*
202  * The architecture-independent dump_stack generator
203  */
204 void dump_stack(void)
205 {
206 	struct pt_regs regs;
207 
208 	prepare_frametrace(&regs);
209 	show_backtrace(current, &regs);
210 }
211 
212 EXPORT_SYMBOL(dump_stack);
213 
214 static void show_code(unsigned int __user *pc)
215 {
216 	long i;
217 	unsigned short __user *pc16 = NULL;
218 
219 	printk("\nCode:");
220 
221 	if ((unsigned long)pc & 1)
222 		pc16 = (unsigned short __user *)((unsigned long)pc & ~1);
223 	for(i = -3 ; i < 6 ; i++) {
224 		unsigned int insn;
225 		if (pc16 ? __get_user(insn, pc16 + i) : __get_user(insn, pc + i)) {
226 			printk(" (Bad address in epc)\n");
227 			break;
228 		}
229 		printk("%c%0*x%c", (i?' ':'<'), pc16 ? 4 : 8, insn, (i?' ':'>'));
230 	}
231 }
232 
233 static void __show_regs(const struct pt_regs *regs)
234 {
235 	const int field = 2 * sizeof(unsigned long);
236 	unsigned int cause = regs->cp0_cause;
237 	int i;
238 
239 	printk("Cpu %d\n", smp_processor_id());
240 
241 	/*
242 	 * Saved main processor registers
243 	 */
244 	for (i = 0; i < 32; ) {
245 		if ((i % 4) == 0)
246 			printk("$%2d   :", i);
247 		if (i == 0)
248 			printk(" %0*lx", field, 0UL);
249 		else if (i == 26 || i == 27)
250 			printk(" %*s", field, "");
251 		else
252 			printk(" %0*lx", field, regs->regs[i]);
253 
254 		i++;
255 		if ((i % 4) == 0)
256 			printk("\n");
257 	}
258 
259 #ifdef CONFIG_CPU_HAS_SMARTMIPS
260 	printk("Acx    : %0*lx\n", field, regs->acx);
261 #endif
262 	printk("Hi    : %0*lx\n", field, regs->hi);
263 	printk("Lo    : %0*lx\n", field, regs->lo);
264 
265 	/*
266 	 * Saved cp0 registers
267 	 */
268 	printk("epc   : %0*lx %pS\n", field, regs->cp0_epc,
269 	       (void *) regs->cp0_epc);
270 	printk("    %s\n", print_tainted());
271 	printk("ra    : %0*lx %pS\n", field, regs->regs[31],
272 	       (void *) regs->regs[31]);
273 
274 	printk("Status: %08x    ", (uint32_t) regs->cp0_status);
275 
276 	if (current_cpu_data.isa_level == MIPS_CPU_ISA_I) {
277 		if (regs->cp0_status & ST0_KUO)
278 			printk("KUo ");
279 		if (regs->cp0_status & ST0_IEO)
280 			printk("IEo ");
281 		if (regs->cp0_status & ST0_KUP)
282 			printk("KUp ");
283 		if (regs->cp0_status & ST0_IEP)
284 			printk("IEp ");
285 		if (regs->cp0_status & ST0_KUC)
286 			printk("KUc ");
287 		if (regs->cp0_status & ST0_IEC)
288 			printk("IEc ");
289 	} else {
290 		if (regs->cp0_status & ST0_KX)
291 			printk("KX ");
292 		if (regs->cp0_status & ST0_SX)
293 			printk("SX ");
294 		if (regs->cp0_status & ST0_UX)
295 			printk("UX ");
296 		switch (regs->cp0_status & ST0_KSU) {
297 		case KSU_USER:
298 			printk("USER ");
299 			break;
300 		case KSU_SUPERVISOR:
301 			printk("SUPERVISOR ");
302 			break;
303 		case KSU_KERNEL:
304 			printk("KERNEL ");
305 			break;
306 		default:
307 			printk("BAD_MODE ");
308 			break;
309 		}
310 		if (regs->cp0_status & ST0_ERL)
311 			printk("ERL ");
312 		if (regs->cp0_status & ST0_EXL)
313 			printk("EXL ");
314 		if (regs->cp0_status & ST0_IE)
315 			printk("IE ");
316 	}
317 	printk("\n");
318 
319 	printk("Cause : %08x\n", cause);
320 
321 	cause = (cause & CAUSEF_EXCCODE) >> CAUSEB_EXCCODE;
322 	if (1 <= cause && cause <= 5)
323 		printk("BadVA : %0*lx\n", field, regs->cp0_badvaddr);
324 
325 	printk("PrId  : %08x (%s)\n", read_c0_prid(),
326 	       cpu_name_string());
327 }
328 
329 /*
330  * FIXME: really the generic show_regs should take a const pointer argument.
331  */
332 void show_regs(struct pt_regs *regs)
333 {
334 	__show_regs((struct pt_regs *)regs);
335 }
336 
337 void show_registers(const struct pt_regs *regs)
338 {
339 	const int field = 2 * sizeof(unsigned long);
340 
341 	__show_regs(regs);
342 	print_modules();
343 	printk("Process %s (pid: %d, threadinfo=%p, task=%p, tls=%0*lx)\n",
344 	       current->comm, current->pid, current_thread_info(), current,
345 	      field, current_thread_info()->tp_value);
346 	if (cpu_has_userlocal) {
347 		unsigned long tls;
348 
349 		tls = read_c0_userlocal();
350 		if (tls != current_thread_info()->tp_value)
351 			printk("*HwTLS: %0*lx\n", field, tls);
352 	}
353 
354 	show_stacktrace(current, regs);
355 	show_code((unsigned int __user *) regs->cp0_epc);
356 	printk("\n");
357 }
358 
359 static DEFINE_SPINLOCK(die_lock);
360 
361 void __noreturn die(const char * str, struct pt_regs * regs)
362 {
363 	static int die_counter;
364 	int sig = SIGSEGV;
365 #ifdef CONFIG_MIPS_MT_SMTC
366 	unsigned long dvpret = dvpe();
367 #endif /* CONFIG_MIPS_MT_SMTC */
368 
369 	notify_die(DIE_OOPS, str, (struct pt_regs *)regs, SIGSEGV, 0, 0);
370 
371 	console_verbose();
372 	spin_lock_irq(&die_lock);
373 	bust_spinlocks(1);
374 #ifdef CONFIG_MIPS_MT_SMTC
375 	mips_mt_regdump(dvpret);
376 #endif /* CONFIG_MIPS_MT_SMTC */
377 
378 	if (notify_die(DIE_OOPS, str, regs, 0, current->thread.trap_no, SIGSEGV) == NOTIFY_STOP)
379 		sig = 0;
380 
381 	printk("%s[#%d]:\n", str, ++die_counter);
382 	show_registers(regs);
383 	add_taint(TAINT_DIE);
384 	spin_unlock_irq(&die_lock);
385 
386 	if (in_interrupt())
387 		panic("Fatal exception in interrupt");
388 
389 	if (panic_on_oops) {
390 		printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
391 		ssleep(5);
392 		panic("Fatal exception");
393 	}
394 
395 	do_exit(sig);
396 }
397 
398 extern struct exception_table_entry __start___dbe_table[];
399 extern struct exception_table_entry __stop___dbe_table[];
400 
401 __asm__(
402 "	.section	__dbe_table, \"a\"\n"
403 "	.previous			\n");
404 
405 /* Given an address, look for it in the exception tables. */
406 static const struct exception_table_entry *search_dbe_tables(unsigned long addr)
407 {
408 	const struct exception_table_entry *e;
409 
410 	e = search_extable(__start___dbe_table, __stop___dbe_table - 1, addr);
411 	if (!e)
412 		e = search_module_dbetables(addr);
413 	return e;
414 }
415 
416 asmlinkage void do_be(struct pt_regs *regs)
417 {
418 	const int field = 2 * sizeof(unsigned long);
419 	const struct exception_table_entry *fixup = NULL;
420 	int data = regs->cp0_cause & 4;
421 	int action = MIPS_BE_FATAL;
422 
423 	/* XXX For now.  Fixme, this searches the wrong table ...  */
424 	if (data && !user_mode(regs))
425 		fixup = search_dbe_tables(exception_epc(regs));
426 
427 	if (fixup)
428 		action = MIPS_BE_FIXUP;
429 
430 	if (board_be_handler)
431 		action = board_be_handler(regs, fixup != NULL);
432 
433 	switch (action) {
434 	case MIPS_BE_DISCARD:
435 		return;
436 	case MIPS_BE_FIXUP:
437 		if (fixup) {
438 			regs->cp0_epc = fixup->nextinsn;
439 			return;
440 		}
441 		break;
442 	default:
443 		break;
444 	}
445 
446 	/*
447 	 * Assume it would be too dangerous to continue ...
448 	 */
449 	printk(KERN_ALERT "%s bus error, epc == %0*lx, ra == %0*lx\n",
450 	       data ? "Data" : "Instruction",
451 	       field, regs->cp0_epc, field, regs->regs[31]);
452 	if (notify_die(DIE_OOPS, "bus error", regs, SIGBUS, 0, 0)
453 	    == NOTIFY_STOP)
454 		return;
455 
456 	die_if_kernel("Oops", regs);
457 	force_sig(SIGBUS, current);
458 }
459 
460 /*
461  * ll/sc, rdhwr, sync emulation
462  */
463 
464 #define OPCODE 0xfc000000
465 #define BASE   0x03e00000
466 #define RT     0x001f0000
467 #define OFFSET 0x0000ffff
468 #define LL     0xc0000000
469 #define SC     0xe0000000
470 #define SPEC0  0x00000000
471 #define SPEC3  0x7c000000
472 #define RD     0x0000f800
473 #define FUNC   0x0000003f
474 #define SYNC   0x0000000f
475 #define RDHWR  0x0000003b
476 
477 /*
478  * The ll_bit is cleared by r*_switch.S
479  */
480 
481 unsigned int ll_bit;
482 struct task_struct *ll_task;
483 
484 static inline int simulate_ll(struct pt_regs *regs, unsigned int opcode)
485 {
486 	unsigned long value, __user *vaddr;
487 	long offset;
488 
489 	/*
490 	 * analyse the ll instruction that just caused a ri exception
491 	 * and put the referenced address to addr.
492 	 */
493 
494 	/* sign extend offset */
495 	offset = opcode & OFFSET;
496 	offset <<= 16;
497 	offset >>= 16;
498 
499 	vaddr = (unsigned long __user *)
500 	        ((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
501 
502 	if ((unsigned long)vaddr & 3)
503 		return SIGBUS;
504 	if (get_user(value, vaddr))
505 		return SIGSEGV;
506 
507 	preempt_disable();
508 
509 	if (ll_task == NULL || ll_task == current) {
510 		ll_bit = 1;
511 	} else {
512 		ll_bit = 0;
513 	}
514 	ll_task = current;
515 
516 	preempt_enable();
517 
518 	regs->regs[(opcode & RT) >> 16] = value;
519 
520 	return 0;
521 }
522 
523 static inline int simulate_sc(struct pt_regs *regs, unsigned int opcode)
524 {
525 	unsigned long __user *vaddr;
526 	unsigned long reg;
527 	long offset;
528 
529 	/*
530 	 * analyse the sc instruction that just caused a ri exception
531 	 * and put the referenced address to addr.
532 	 */
533 
534 	/* sign extend offset */
535 	offset = opcode & OFFSET;
536 	offset <<= 16;
537 	offset >>= 16;
538 
539 	vaddr = (unsigned long __user *)
540 	        ((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
541 	reg = (opcode & RT) >> 16;
542 
543 	if ((unsigned long)vaddr & 3)
544 		return SIGBUS;
545 
546 	preempt_disable();
547 
548 	if (ll_bit == 0 || ll_task != current) {
549 		regs->regs[reg] = 0;
550 		preempt_enable();
551 		return 0;
552 	}
553 
554 	preempt_enable();
555 
556 	if (put_user(regs->regs[reg], vaddr))
557 		return SIGSEGV;
558 
559 	regs->regs[reg] = 1;
560 
561 	return 0;
562 }
563 
564 /*
565  * ll uses the opcode of lwc0 and sc uses the opcode of swc0.  That is both
566  * opcodes are supposed to result in coprocessor unusable exceptions if
567  * executed on ll/sc-less processors.  That's the theory.  In practice a
568  * few processors such as NEC's VR4100 throw reserved instruction exceptions
569  * instead, so we're doing the emulation thing in both exception handlers.
570  */
571 static int simulate_llsc(struct pt_regs *regs, unsigned int opcode)
572 {
573 	if ((opcode & OPCODE) == LL)
574 		return simulate_ll(regs, opcode);
575 	if ((opcode & OPCODE) == SC)
576 		return simulate_sc(regs, opcode);
577 
578 	return -1;			/* Must be something else ... */
579 }
580 
581 /*
582  * Simulate trapping 'rdhwr' instructions to provide user accessible
583  * registers not implemented in hardware.
584  */
585 static int simulate_rdhwr(struct pt_regs *regs, unsigned int opcode)
586 {
587 	struct thread_info *ti = task_thread_info(current);
588 
589 	if ((opcode & OPCODE) == SPEC3 && (opcode & FUNC) == RDHWR) {
590 		int rd = (opcode & RD) >> 11;
591 		int rt = (opcode & RT) >> 16;
592 		switch (rd) {
593 		case 0:		/* CPU number */
594 			regs->regs[rt] = smp_processor_id();
595 			return 0;
596 		case 1:		/* SYNCI length */
597 			regs->regs[rt] = min(current_cpu_data.dcache.linesz,
598 					     current_cpu_data.icache.linesz);
599 			return 0;
600 		case 2:		/* Read count register */
601 			regs->regs[rt] = read_c0_count();
602 			return 0;
603 		case 3:		/* Count register resolution */
604 			switch (current_cpu_data.cputype) {
605 			case CPU_20KC:
606 			case CPU_25KF:
607 				regs->regs[rt] = 1;
608 				break;
609 			default:
610 				regs->regs[rt] = 2;
611 			}
612 			return 0;
613 		case 29:
614 			regs->regs[rt] = ti->tp_value;
615 			return 0;
616 		default:
617 			return -1;
618 		}
619 	}
620 
621 	/* Not ours.  */
622 	return -1;
623 }
624 
625 static int simulate_sync(struct pt_regs *regs, unsigned int opcode)
626 {
627 	if ((opcode & OPCODE) == SPEC0 && (opcode & FUNC) == SYNC)
628 		return 0;
629 
630 	return -1;			/* Must be something else ... */
631 }
632 
633 asmlinkage void do_ov(struct pt_regs *regs)
634 {
635 	siginfo_t info;
636 
637 	die_if_kernel("Integer overflow", regs);
638 
639 	info.si_code = FPE_INTOVF;
640 	info.si_signo = SIGFPE;
641 	info.si_errno = 0;
642 	info.si_addr = (void __user *) regs->cp0_epc;
643 	force_sig_info(SIGFPE, &info, current);
644 }
645 
646 /*
647  * XXX Delayed fp exceptions when doing a lazy ctx switch XXX
648  */
649 asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
650 {
651 	siginfo_t info;
652 
653 	if (notify_die(DIE_FP, "FP exception", regs, SIGFPE, 0, 0)
654 	    == NOTIFY_STOP)
655 		return;
656 	die_if_kernel("FP exception in kernel code", regs);
657 
658 	if (fcr31 & FPU_CSR_UNI_X) {
659 		int sig;
660 
661 		/*
662 		 * Unimplemented operation exception.  If we've got the full
663 		 * software emulator on-board, let's use it...
664 		 *
665 		 * Force FPU to dump state into task/thread context.  We're
666 		 * moving a lot of data here for what is probably a single
667 		 * instruction, but the alternative is to pre-decode the FP
668 		 * register operands before invoking the emulator, which seems
669 		 * a bit extreme for what should be an infrequent event.
670 		 */
671 		/* Ensure 'resume' not overwrite saved fp context again. */
672 		lose_fpu(1);
673 
674 		/* Run the emulator */
675 		sig = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1);
676 
677 		/*
678 		 * We can't allow the emulated instruction to leave any of
679 		 * the cause bit set in $fcr31.
680 		 */
681 		current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
682 
683 		/* Restore the hardware register state */
684 		own_fpu(1);	/* Using the FPU again.  */
685 
686 		/* If something went wrong, signal */
687 		if (sig)
688 			force_sig(sig, current);
689 
690 		return;
691 	} else if (fcr31 & FPU_CSR_INV_X)
692 		info.si_code = FPE_FLTINV;
693 	else if (fcr31 & FPU_CSR_DIV_X)
694 		info.si_code = FPE_FLTDIV;
695 	else if (fcr31 & FPU_CSR_OVF_X)
696 		info.si_code = FPE_FLTOVF;
697 	else if (fcr31 & FPU_CSR_UDF_X)
698 		info.si_code = FPE_FLTUND;
699 	else if (fcr31 & FPU_CSR_INE_X)
700 		info.si_code = FPE_FLTRES;
701 	else
702 		info.si_code = __SI_FAULT;
703 	info.si_signo = SIGFPE;
704 	info.si_errno = 0;
705 	info.si_addr = (void __user *) regs->cp0_epc;
706 	force_sig_info(SIGFPE, &info, current);
707 }
708 
709 static void do_trap_or_bp(struct pt_regs *regs, unsigned int code,
710 	const char *str)
711 {
712 	siginfo_t info;
713 	char b[40];
714 
715 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
716 	if (kgdb_ll_trap(DIE_TRAP, str, regs, code, 0, 0) == NOTIFY_STOP)
717 		return;
718 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
719 
720 	if (notify_die(DIE_TRAP, str, regs, code, 0, 0) == NOTIFY_STOP)
721 		return;
722 
723 	/*
724 	 * A short test says that IRIX 5.3 sends SIGTRAP for all trap
725 	 * insns, even for trap and break codes that indicate arithmetic
726 	 * failures.  Weird ...
727 	 * But should we continue the brokenness???  --macro
728 	 */
729 	switch (code) {
730 	case BRK_OVERFLOW:
731 	case BRK_DIVZERO:
732 		scnprintf(b, sizeof(b), "%s instruction in kernel code", str);
733 		die_if_kernel(b, regs);
734 		if (code == BRK_DIVZERO)
735 			info.si_code = FPE_INTDIV;
736 		else
737 			info.si_code = FPE_INTOVF;
738 		info.si_signo = SIGFPE;
739 		info.si_errno = 0;
740 		info.si_addr = (void __user *) regs->cp0_epc;
741 		force_sig_info(SIGFPE, &info, current);
742 		break;
743 	case BRK_BUG:
744 		die_if_kernel("Kernel bug detected", regs);
745 		force_sig(SIGTRAP, current);
746 		break;
747 	case BRK_MEMU:
748 		/*
749 		 * Address errors may be deliberately induced by the FPU
750 		 * emulator to retake control of the CPU after executing the
751 		 * instruction in the delay slot of an emulated branch.
752 		 *
753 		 * Terminate if exception was recognized as a delay slot return
754 		 * otherwise handle as normal.
755 		 */
756 		if (do_dsemulret(regs))
757 			return;
758 
759 		die_if_kernel("Math emu break/trap", regs);
760 		force_sig(SIGTRAP, current);
761 		break;
762 	default:
763 		scnprintf(b, sizeof(b), "%s instruction in kernel code", str);
764 		die_if_kernel(b, regs);
765 		force_sig(SIGTRAP, current);
766 	}
767 }
768 
769 asmlinkage void do_bp(struct pt_regs *regs)
770 {
771 	unsigned int opcode, bcode;
772 
773 	if (__get_user(opcode, (unsigned int __user *) exception_epc(regs)))
774 		goto out_sigsegv;
775 
776 	/*
777 	 * There is the ancient bug in the MIPS assemblers that the break
778 	 * code starts left to bit 16 instead to bit 6 in the opcode.
779 	 * Gas is bug-compatible, but not always, grrr...
780 	 * We handle both cases with a simple heuristics.  --macro
781 	 */
782 	bcode = ((opcode >> 6) & ((1 << 20) - 1));
783 	if (bcode >= (1 << 10))
784 		bcode >>= 10;
785 
786 	do_trap_or_bp(regs, bcode, "Break");
787 	return;
788 
789 out_sigsegv:
790 	force_sig(SIGSEGV, current);
791 }
792 
793 asmlinkage void do_tr(struct pt_regs *regs)
794 {
795 	unsigned int opcode, tcode = 0;
796 
797 	if (__get_user(opcode, (unsigned int __user *) exception_epc(regs)))
798 		goto out_sigsegv;
799 
800 	/* Immediate versions don't provide a code.  */
801 	if (!(opcode & OPCODE))
802 		tcode = ((opcode >> 6) & ((1 << 10) - 1));
803 
804 	do_trap_or_bp(regs, tcode, "Trap");
805 	return;
806 
807 out_sigsegv:
808 	force_sig(SIGSEGV, current);
809 }
810 
811 asmlinkage void do_ri(struct pt_regs *regs)
812 {
813 	unsigned int __user *epc = (unsigned int __user *)exception_epc(regs);
814 	unsigned long old_epc = regs->cp0_epc;
815 	unsigned int opcode = 0;
816 	int status = -1;
817 
818 	if (notify_die(DIE_RI, "RI Fault", regs, SIGSEGV, 0, 0)
819 	    == NOTIFY_STOP)
820 		return;
821 
822 	die_if_kernel("Reserved instruction in kernel code", regs);
823 
824 	if (unlikely(compute_return_epc(regs) < 0))
825 		return;
826 
827 	if (unlikely(get_user(opcode, epc) < 0))
828 		status = SIGSEGV;
829 
830 	if (!cpu_has_llsc && status < 0)
831 		status = simulate_llsc(regs, opcode);
832 
833 	if (status < 0)
834 		status = simulate_rdhwr(regs, opcode);
835 
836 	if (status < 0)
837 		status = simulate_sync(regs, opcode);
838 
839 	if (status < 0)
840 		status = SIGILL;
841 
842 	if (unlikely(status > 0)) {
843 		regs->cp0_epc = old_epc;		/* Undo skip-over.  */
844 		force_sig(status, current);
845 	}
846 }
847 
848 /*
849  * MIPS MT processors may have fewer FPU contexts than CPU threads. If we've
850  * emulated more than some threshold number of instructions, force migration to
851  * a "CPU" that has FP support.
852  */
853 static void mt_ase_fp_affinity(void)
854 {
855 #ifdef CONFIG_MIPS_MT_FPAFF
856 	if (mt_fpemul_threshold > 0 &&
857 	     ((current->thread.emulated_fp++ > mt_fpemul_threshold))) {
858 		/*
859 		 * If there's no FPU present, or if the application has already
860 		 * restricted the allowed set to exclude any CPUs with FPUs,
861 		 * we'll skip the procedure.
862 		 */
863 		if (cpus_intersects(current->cpus_allowed, mt_fpu_cpumask)) {
864 			cpumask_t tmask;
865 
866 			current->thread.user_cpus_allowed
867 				= current->cpus_allowed;
868 			cpus_and(tmask, current->cpus_allowed,
869 				mt_fpu_cpumask);
870 			set_cpus_allowed_ptr(current, &tmask);
871 			set_thread_flag(TIF_FPUBOUND);
872 		}
873 	}
874 #endif /* CONFIG_MIPS_MT_FPAFF */
875 }
876 
877 /*
878  * No lock; only written during early bootup by CPU 0.
879  */
880 static RAW_NOTIFIER_HEAD(cu2_chain);
881 
882 int __ref register_cu2_notifier(struct notifier_block *nb)
883 {
884 	return raw_notifier_chain_register(&cu2_chain, nb);
885 }
886 
887 int cu2_notifier_call_chain(unsigned long val, void *v)
888 {
889 	return raw_notifier_call_chain(&cu2_chain, val, v);
890 }
891 
892 static int default_cu2_call(struct notifier_block *nfb, unsigned long action,
893         void *data)
894 {
895 	struct pt_regs *regs = data;
896 
897 	switch (action) {
898 	default:
899 		die_if_kernel("Unhandled kernel unaligned access or invalid "
900 			      "instruction", regs);
901 		/* Fall through  */
902 
903 	case CU2_EXCEPTION:
904 		force_sig(SIGILL, current);
905 	}
906 
907 	return NOTIFY_OK;
908 }
909 
910 static struct notifier_block default_cu2_notifier = {
911 	.notifier_call	= default_cu2_call,
912 	.priority	= 0x80000000,		/* Run last  */
913 };
914 
915 asmlinkage void do_cpu(struct pt_regs *regs)
916 {
917 	unsigned int __user *epc;
918 	unsigned long old_epc;
919 	unsigned int opcode;
920 	unsigned int cpid;
921 	int status;
922 	unsigned long __maybe_unused flags;
923 
924 	die_if_kernel("do_cpu invoked from kernel context!", regs);
925 
926 	cpid = (regs->cp0_cause >> CAUSEB_CE) & 3;
927 
928 	switch (cpid) {
929 	case 0:
930 		epc = (unsigned int __user *)exception_epc(regs);
931 		old_epc = regs->cp0_epc;
932 		opcode = 0;
933 		status = -1;
934 
935 		if (unlikely(compute_return_epc(regs) < 0))
936 			return;
937 
938 		if (unlikely(get_user(opcode, epc) < 0))
939 			status = SIGSEGV;
940 
941 		if (!cpu_has_llsc && status < 0)
942 			status = simulate_llsc(regs, opcode);
943 
944 		if (status < 0)
945 			status = simulate_rdhwr(regs, opcode);
946 
947 		if (status < 0)
948 			status = SIGILL;
949 
950 		if (unlikely(status > 0)) {
951 			regs->cp0_epc = old_epc;	/* Undo skip-over.  */
952 			force_sig(status, current);
953 		}
954 
955 		return;
956 
957 	case 1:
958 		if (used_math())	/* Using the FPU again.  */
959 			own_fpu(1);
960 		else {			/* First time FPU user.  */
961 			init_fpu();
962 			set_used_math();
963 		}
964 
965 		if (!raw_cpu_has_fpu) {
966 			int sig;
967 			sig = fpu_emulator_cop1Handler(regs,
968 						&current->thread.fpu, 0);
969 			if (sig)
970 				force_sig(sig, current);
971 			else
972 				mt_ase_fp_affinity();
973 		}
974 
975 		return;
976 
977 	case 2:
978 		raw_notifier_call_chain(&cu2_chain, CU2_EXCEPTION, regs);
979 		break;
980 
981 	case 3:
982 		break;
983 	}
984 
985 	force_sig(SIGILL, current);
986 }
987 
988 asmlinkage void do_mdmx(struct pt_regs *regs)
989 {
990 	force_sig(SIGILL, current);
991 }
992 
993 /*
994  * Called with interrupts disabled.
995  */
996 asmlinkage void do_watch(struct pt_regs *regs)
997 {
998 	u32 cause;
999 
1000 	/*
1001 	 * Clear WP (bit 22) bit of cause register so we don't loop
1002 	 * forever.
1003 	 */
1004 	cause = read_c0_cause();
1005 	cause &= ~(1 << 22);
1006 	write_c0_cause(cause);
1007 
1008 	/*
1009 	 * If the current thread has the watch registers loaded, save
1010 	 * their values and send SIGTRAP.  Otherwise another thread
1011 	 * left the registers set, clear them and continue.
1012 	 */
1013 	if (test_tsk_thread_flag(current, TIF_LOAD_WATCH)) {
1014 		mips_read_watch_registers();
1015 		local_irq_enable();
1016 		force_sig(SIGTRAP, current);
1017 	} else {
1018 		mips_clear_watch_registers();
1019 		local_irq_enable();
1020 	}
1021 }
1022 
1023 asmlinkage void do_mcheck(struct pt_regs *regs)
1024 {
1025 	const int field = 2 * sizeof(unsigned long);
1026 	int multi_match = regs->cp0_status & ST0_TS;
1027 
1028 	show_regs(regs);
1029 
1030 	if (multi_match) {
1031 		printk("Index   : %0x\n", read_c0_index());
1032 		printk("Pagemask: %0x\n", read_c0_pagemask());
1033 		printk("EntryHi : %0*lx\n", field, read_c0_entryhi());
1034 		printk("EntryLo0: %0*lx\n", field, read_c0_entrylo0());
1035 		printk("EntryLo1: %0*lx\n", field, read_c0_entrylo1());
1036 		printk("\n");
1037 		dump_tlb_all();
1038 	}
1039 
1040 	show_code((unsigned int __user *) regs->cp0_epc);
1041 
1042 	/*
1043 	 * Some chips may have other causes of machine check (e.g. SB1
1044 	 * graduation timer)
1045 	 */
1046 	panic("Caught Machine Check exception - %scaused by multiple "
1047 	      "matching entries in the TLB.",
1048 	      (multi_match) ? "" : "not ");
1049 }
1050 
1051 asmlinkage void do_mt(struct pt_regs *regs)
1052 {
1053 	int subcode;
1054 
1055 	subcode = (read_vpe_c0_vpecontrol() & VPECONTROL_EXCPT)
1056 			>> VPECONTROL_EXCPT_SHIFT;
1057 	switch (subcode) {
1058 	case 0:
1059 		printk(KERN_DEBUG "Thread Underflow\n");
1060 		break;
1061 	case 1:
1062 		printk(KERN_DEBUG "Thread Overflow\n");
1063 		break;
1064 	case 2:
1065 		printk(KERN_DEBUG "Invalid YIELD Qualifier\n");
1066 		break;
1067 	case 3:
1068 		printk(KERN_DEBUG "Gating Storage Exception\n");
1069 		break;
1070 	case 4:
1071 		printk(KERN_DEBUG "YIELD Scheduler Exception\n");
1072 		break;
1073 	case 5:
1074 		printk(KERN_DEBUG "Gating Storage Schedulier Exception\n");
1075 		break;
1076 	default:
1077 		printk(KERN_DEBUG "*** UNKNOWN THREAD EXCEPTION %d ***\n",
1078 			subcode);
1079 		break;
1080 	}
1081 	die_if_kernel("MIPS MT Thread exception in kernel", regs);
1082 
1083 	force_sig(SIGILL, current);
1084 }
1085 
1086 
1087 asmlinkage void do_dsp(struct pt_regs *regs)
1088 {
1089 	if (cpu_has_dsp)
1090 		panic("Unexpected DSP exception\n");
1091 
1092 	force_sig(SIGILL, current);
1093 }
1094 
1095 asmlinkage void do_reserved(struct pt_regs *regs)
1096 {
1097 	/*
1098 	 * Game over - no way to handle this if it ever occurs.  Most probably
1099 	 * caused by a new unknown cpu type or after another deadly
1100 	 * hard/software error.
1101 	 */
1102 	show_regs(regs);
1103 	panic("Caught reserved exception %ld - should not happen.",
1104 	      (regs->cp0_cause & 0x7f) >> 2);
1105 }
1106 
1107 static int __initdata l1parity = 1;
1108 static int __init nol1parity(char *s)
1109 {
1110 	l1parity = 0;
1111 	return 1;
1112 }
1113 __setup("nol1par", nol1parity);
1114 static int __initdata l2parity = 1;
1115 static int __init nol2parity(char *s)
1116 {
1117 	l2parity = 0;
1118 	return 1;
1119 }
1120 __setup("nol2par", nol2parity);
1121 
1122 /*
1123  * Some MIPS CPUs can enable/disable for cache parity detection, but do
1124  * it different ways.
1125  */
1126 static inline void parity_protection_init(void)
1127 {
1128 	switch (current_cpu_type()) {
1129 	case CPU_24K:
1130 	case CPU_34K:
1131 	case CPU_74K:
1132 	case CPU_1004K:
1133 		{
1134 #define ERRCTL_PE	0x80000000
1135 #define ERRCTL_L2P	0x00800000
1136 			unsigned long errctl;
1137 			unsigned int l1parity_present, l2parity_present;
1138 
1139 			errctl = read_c0_ecc();
1140 			errctl &= ~(ERRCTL_PE|ERRCTL_L2P);
1141 
1142 			/* probe L1 parity support */
1143 			write_c0_ecc(errctl | ERRCTL_PE);
1144 			back_to_back_c0_hazard();
1145 			l1parity_present = (read_c0_ecc() & ERRCTL_PE);
1146 
1147 			/* probe L2 parity support */
1148 			write_c0_ecc(errctl|ERRCTL_L2P);
1149 			back_to_back_c0_hazard();
1150 			l2parity_present = (read_c0_ecc() & ERRCTL_L2P);
1151 
1152 			if (l1parity_present && l2parity_present) {
1153 				if (l1parity)
1154 					errctl |= ERRCTL_PE;
1155 				if (l1parity ^ l2parity)
1156 					errctl |= ERRCTL_L2P;
1157 			} else if (l1parity_present) {
1158 				if (l1parity)
1159 					errctl |= ERRCTL_PE;
1160 			} else if (l2parity_present) {
1161 				if (l2parity)
1162 					errctl |= ERRCTL_L2P;
1163 			} else {
1164 				/* No parity available */
1165 			}
1166 
1167 			printk(KERN_INFO "Writing ErrCtl register=%08lx\n", errctl);
1168 
1169 			write_c0_ecc(errctl);
1170 			back_to_back_c0_hazard();
1171 			errctl = read_c0_ecc();
1172 			printk(KERN_INFO "Readback ErrCtl register=%08lx\n", errctl);
1173 
1174 			if (l1parity_present)
1175 				printk(KERN_INFO "Cache parity protection %sabled\n",
1176 				       (errctl & ERRCTL_PE) ? "en" : "dis");
1177 
1178 			if (l2parity_present) {
1179 				if (l1parity_present && l1parity)
1180 					errctl ^= ERRCTL_L2P;
1181 				printk(KERN_INFO "L2 cache parity protection %sabled\n",
1182 				       (errctl & ERRCTL_L2P) ? "en" : "dis");
1183 			}
1184 		}
1185 		break;
1186 
1187 	case CPU_5KC:
1188 		write_c0_ecc(0x80000000);
1189 		back_to_back_c0_hazard();
1190 		/* Set the PE bit (bit 31) in the c0_errctl register. */
1191 		printk(KERN_INFO "Cache parity protection %sabled\n",
1192 		       (read_c0_ecc() & 0x80000000) ? "en" : "dis");
1193 		break;
1194 	case CPU_20KC:
1195 	case CPU_25KF:
1196 		/* Clear the DE bit (bit 16) in the c0_status register. */
1197 		printk(KERN_INFO "Enable cache parity protection for "
1198 		       "MIPS 20KC/25KF CPUs.\n");
1199 		clear_c0_status(ST0_DE);
1200 		break;
1201 	default:
1202 		break;
1203 	}
1204 }
1205 
1206 asmlinkage void cache_parity_error(void)
1207 {
1208 	const int field = 2 * sizeof(unsigned long);
1209 	unsigned int reg_val;
1210 
1211 	/* For the moment, report the problem and hang. */
1212 	printk("Cache error exception:\n");
1213 	printk("cp0_errorepc == %0*lx\n", field, read_c0_errorepc());
1214 	reg_val = read_c0_cacheerr();
1215 	printk("c0_cacheerr == %08x\n", reg_val);
1216 
1217 	printk("Decoded c0_cacheerr: %s cache fault in %s reference.\n",
1218 	       reg_val & (1<<30) ? "secondary" : "primary",
1219 	       reg_val & (1<<31) ? "data" : "insn");
1220 	printk("Error bits: %s%s%s%s%s%s%s\n",
1221 	       reg_val & (1<<29) ? "ED " : "",
1222 	       reg_val & (1<<28) ? "ET " : "",
1223 	       reg_val & (1<<26) ? "EE " : "",
1224 	       reg_val & (1<<25) ? "EB " : "",
1225 	       reg_val & (1<<24) ? "EI " : "",
1226 	       reg_val & (1<<23) ? "E1 " : "",
1227 	       reg_val & (1<<22) ? "E0 " : "");
1228 	printk("IDX: 0x%08x\n", reg_val & ((1<<22)-1));
1229 
1230 #if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
1231 	if (reg_val & (1<<22))
1232 		printk("DErrAddr0: 0x%0*lx\n", field, read_c0_derraddr0());
1233 
1234 	if (reg_val & (1<<23))
1235 		printk("DErrAddr1: 0x%0*lx\n", field, read_c0_derraddr1());
1236 #endif
1237 
1238 	panic("Can't handle the cache error!");
1239 }
1240 
1241 /*
1242  * SDBBP EJTAG debug exception handler.
1243  * We skip the instruction and return to the next instruction.
1244  */
1245 void ejtag_exception_handler(struct pt_regs *regs)
1246 {
1247 	const int field = 2 * sizeof(unsigned long);
1248 	unsigned long depc, old_epc;
1249 	unsigned int debug;
1250 
1251 	printk(KERN_DEBUG "SDBBP EJTAG debug exception - not handled yet, just ignored!\n");
1252 	depc = read_c0_depc();
1253 	debug = read_c0_debug();
1254 	printk(KERN_DEBUG "c0_depc = %0*lx, DEBUG = %08x\n", field, depc, debug);
1255 	if (debug & 0x80000000) {
1256 		/*
1257 		 * In branch delay slot.
1258 		 * We cheat a little bit here and use EPC to calculate the
1259 		 * debug return address (DEPC). EPC is restored after the
1260 		 * calculation.
1261 		 */
1262 		old_epc = regs->cp0_epc;
1263 		regs->cp0_epc = depc;
1264 		__compute_return_epc(regs);
1265 		depc = regs->cp0_epc;
1266 		regs->cp0_epc = old_epc;
1267 	} else
1268 		depc += 4;
1269 	write_c0_depc(depc);
1270 
1271 #if 0
1272 	printk(KERN_DEBUG "\n\n----- Enable EJTAG single stepping ----\n\n");
1273 	write_c0_debug(debug | 0x100);
1274 #endif
1275 }
1276 
1277 /*
1278  * NMI exception handler.
1279  */
1280 NORET_TYPE void ATTRIB_NORET nmi_exception_handler(struct pt_regs *regs)
1281 {
1282 	bust_spinlocks(1);
1283 	printk("NMI taken!!!!\n");
1284 	die("NMI", regs);
1285 }
1286 
1287 #define VECTORSPACING 0x100	/* for EI/VI mode */
1288 
1289 unsigned long ebase;
1290 unsigned long exception_handlers[32];
1291 unsigned long vi_handlers[64];
1292 
1293 void __init *set_except_vector(int n, void *addr)
1294 {
1295 	unsigned long handler = (unsigned long) addr;
1296 	unsigned long old_handler = exception_handlers[n];
1297 
1298 	exception_handlers[n] = handler;
1299 	if (n == 0 && cpu_has_divec) {
1300 		unsigned long jump_mask = ~((1 << 28) - 1);
1301 		u32 *buf = (u32 *)(ebase + 0x200);
1302 		unsigned int k0 = 26;
1303 		if ((handler & jump_mask) == ((ebase + 0x200) & jump_mask)) {
1304 			uasm_i_j(&buf, handler & ~jump_mask);
1305 			uasm_i_nop(&buf);
1306 		} else {
1307 			UASM_i_LA(&buf, k0, handler);
1308 			uasm_i_jr(&buf, k0);
1309 			uasm_i_nop(&buf);
1310 		}
1311 		local_flush_icache_range(ebase + 0x200, (unsigned long)buf);
1312 	}
1313 	return (void *)old_handler;
1314 }
1315 
1316 static asmlinkage void do_default_vi(void)
1317 {
1318 	show_regs(get_irq_regs());
1319 	panic("Caught unexpected vectored interrupt.");
1320 }
1321 
1322 static void *set_vi_srs_handler(int n, vi_handler_t addr, int srs)
1323 {
1324 	unsigned long handler;
1325 	unsigned long old_handler = vi_handlers[n];
1326 	int srssets = current_cpu_data.srsets;
1327 	u32 *w;
1328 	unsigned char *b;
1329 
1330 	BUG_ON(!cpu_has_veic && !cpu_has_vint);
1331 
1332 	if (addr == NULL) {
1333 		handler = (unsigned long) do_default_vi;
1334 		srs = 0;
1335 	} else
1336 		handler = (unsigned long) addr;
1337 	vi_handlers[n] = (unsigned long) addr;
1338 
1339 	b = (unsigned char *)(ebase + 0x200 + n*VECTORSPACING);
1340 
1341 	if (srs >= srssets)
1342 		panic("Shadow register set %d not supported", srs);
1343 
1344 	if (cpu_has_veic) {
1345 		if (board_bind_eic_interrupt)
1346 			board_bind_eic_interrupt(n, srs);
1347 	} else if (cpu_has_vint) {
1348 		/* SRSMap is only defined if shadow sets are implemented */
1349 		if (srssets > 1)
1350 			change_c0_srsmap(0xf << n*4, srs << n*4);
1351 	}
1352 
1353 	if (srs == 0) {
1354 		/*
1355 		 * If no shadow set is selected then use the default handler
1356 		 * that does normal register saving and a standard interrupt exit
1357 		 */
1358 
1359 		extern char except_vec_vi, except_vec_vi_lui;
1360 		extern char except_vec_vi_ori, except_vec_vi_end;
1361 		extern char rollback_except_vec_vi;
1362 		char *vec_start = (cpu_wait == r4k_wait) ?
1363 			&rollback_except_vec_vi : &except_vec_vi;
1364 #ifdef CONFIG_MIPS_MT_SMTC
1365 		/*
1366 		 * We need to provide the SMTC vectored interrupt handler
1367 		 * not only with the address of the handler, but with the
1368 		 * Status.IM bit to be masked before going there.
1369 		 */
1370 		extern char except_vec_vi_mori;
1371 		const int mori_offset = &except_vec_vi_mori - vec_start;
1372 #endif /* CONFIG_MIPS_MT_SMTC */
1373 		const int handler_len = &except_vec_vi_end - vec_start;
1374 		const int lui_offset = &except_vec_vi_lui - vec_start;
1375 		const int ori_offset = &except_vec_vi_ori - vec_start;
1376 
1377 		if (handler_len > VECTORSPACING) {
1378 			/*
1379 			 * Sigh... panicing won't help as the console
1380 			 * is probably not configured :(
1381 			 */
1382 			panic("VECTORSPACING too small");
1383 		}
1384 
1385 		memcpy(b, vec_start, handler_len);
1386 #ifdef CONFIG_MIPS_MT_SMTC
1387 		BUG_ON(n > 7);	/* Vector index %d exceeds SMTC maximum. */
1388 
1389 		w = (u32 *)(b + mori_offset);
1390 		*w = (*w & 0xffff0000) | (0x100 << n);
1391 #endif /* CONFIG_MIPS_MT_SMTC */
1392 		w = (u32 *)(b + lui_offset);
1393 		*w = (*w & 0xffff0000) | (((u32)handler >> 16) & 0xffff);
1394 		w = (u32 *)(b + ori_offset);
1395 		*w = (*w & 0xffff0000) | ((u32)handler & 0xffff);
1396 		local_flush_icache_range((unsigned long)b,
1397 					 (unsigned long)(b+handler_len));
1398 	}
1399 	else {
1400 		/*
1401 		 * In other cases jump directly to the interrupt handler
1402 		 *
1403 		 * It is the handlers responsibility to save registers if required
1404 		 * (eg hi/lo) and return from the exception using "eret"
1405 		 */
1406 		w = (u32 *)b;
1407 		*w++ = 0x08000000 | (((u32)handler >> 2) & 0x03fffff); /* j handler */
1408 		*w = 0;
1409 		local_flush_icache_range((unsigned long)b,
1410 					 (unsigned long)(b+8));
1411 	}
1412 
1413 	return (void *)old_handler;
1414 }
1415 
1416 void *set_vi_handler(int n, vi_handler_t addr)
1417 {
1418 	return set_vi_srs_handler(n, addr, 0);
1419 }
1420 
1421 extern void cpu_cache_init(void);
1422 extern void tlb_init(void);
1423 extern void flush_tlb_handlers(void);
1424 
1425 /*
1426  * Timer interrupt
1427  */
1428 int cp0_compare_irq;
1429 int cp0_compare_irq_shift;
1430 
1431 /*
1432  * Performance counter IRQ or -1 if shared with timer
1433  */
1434 int cp0_perfcount_irq;
1435 EXPORT_SYMBOL_GPL(cp0_perfcount_irq);
1436 
1437 static int __cpuinitdata noulri;
1438 
1439 static int __init ulri_disable(char *s)
1440 {
1441 	pr_info("Disabling ulri\n");
1442 	noulri = 1;
1443 
1444 	return 1;
1445 }
1446 __setup("noulri", ulri_disable);
1447 
1448 void __cpuinit per_cpu_trap_init(void)
1449 {
1450 	unsigned int cpu = smp_processor_id();
1451 	unsigned int status_set = ST0_CU0;
1452 #ifdef CONFIG_MIPS_MT_SMTC
1453 	int secondaryTC = 0;
1454 	int bootTC = (cpu == 0);
1455 
1456 	/*
1457 	 * Only do per_cpu_trap_init() for first TC of Each VPE.
1458 	 * Note that this hack assumes that the SMTC init code
1459 	 * assigns TCs consecutively and in ascending order.
1460 	 */
1461 
1462 	if (((read_c0_tcbind() & TCBIND_CURTC) != 0) &&
1463 	    ((read_c0_tcbind() & TCBIND_CURVPE) == cpu_data[cpu - 1].vpe_id))
1464 		secondaryTC = 1;
1465 #endif /* CONFIG_MIPS_MT_SMTC */
1466 
1467 	/*
1468 	 * Disable coprocessors and select 32-bit or 64-bit addressing
1469 	 * and the 16/32 or 32/32 FPR register model.  Reset the BEV
1470 	 * flag that some firmware may have left set and the TS bit (for
1471 	 * IP27).  Set XX for ISA IV code to work.
1472 	 */
1473 #ifdef CONFIG_64BIT
1474 	status_set |= ST0_FR|ST0_KX|ST0_SX|ST0_UX;
1475 #endif
1476 	if (current_cpu_data.isa_level == MIPS_CPU_ISA_IV)
1477 		status_set |= ST0_XX;
1478 	if (cpu_has_dsp)
1479 		status_set |= ST0_MX;
1480 
1481 	change_c0_status(ST0_CU|ST0_MX|ST0_RE|ST0_FR|ST0_BEV|ST0_TS|ST0_KX|ST0_SX|ST0_UX,
1482 			 status_set);
1483 
1484 	if (cpu_has_mips_r2) {
1485 		unsigned int enable = 0x0000000f | cpu_hwrena_impl_bits;
1486 
1487 		if (!noulri && cpu_has_userlocal)
1488 			enable |= (1 << 29);
1489 
1490 		write_c0_hwrena(enable);
1491 	}
1492 
1493 #ifdef CONFIG_MIPS_MT_SMTC
1494 	if (!secondaryTC) {
1495 #endif /* CONFIG_MIPS_MT_SMTC */
1496 
1497 	if (cpu_has_veic || cpu_has_vint) {
1498 		unsigned long sr = set_c0_status(ST0_BEV);
1499 		write_c0_ebase(ebase);
1500 		write_c0_status(sr);
1501 		/* Setting vector spacing enables EI/VI mode  */
1502 		change_c0_intctl(0x3e0, VECTORSPACING);
1503 	}
1504 	if (cpu_has_divec) {
1505 		if (cpu_has_mipsmt) {
1506 			unsigned int vpflags = dvpe();
1507 			set_c0_cause(CAUSEF_IV);
1508 			evpe(vpflags);
1509 		} else
1510 			set_c0_cause(CAUSEF_IV);
1511 	}
1512 
1513 	/*
1514 	 * Before R2 both interrupt numbers were fixed to 7, so on R2 only:
1515 	 *
1516 	 *  o read IntCtl.IPTI to determine the timer interrupt
1517 	 *  o read IntCtl.IPPCI to determine the performance counter interrupt
1518 	 */
1519 	if (cpu_has_mips_r2) {
1520 		cp0_compare_irq_shift = CAUSEB_TI - CAUSEB_IP;
1521 		cp0_compare_irq = (read_c0_intctl() >> INTCTLB_IPTI) & 7;
1522 		cp0_perfcount_irq = (read_c0_intctl() >> INTCTLB_IPPCI) & 7;
1523 		if (cp0_perfcount_irq == cp0_compare_irq)
1524 			cp0_perfcount_irq = -1;
1525 	} else {
1526 		cp0_compare_irq = CP0_LEGACY_COMPARE_IRQ;
1527 		cp0_compare_irq_shift = cp0_compare_irq;
1528 		cp0_perfcount_irq = -1;
1529 	}
1530 
1531 #ifdef CONFIG_MIPS_MT_SMTC
1532 	}
1533 #endif /* CONFIG_MIPS_MT_SMTC */
1534 
1535 	cpu_data[cpu].asid_cache = ASID_FIRST_VERSION;
1536 	TLBMISS_HANDLER_SETUP();
1537 
1538 	atomic_inc(&init_mm.mm_count);
1539 	current->active_mm = &init_mm;
1540 	BUG_ON(current->mm);
1541 	enter_lazy_tlb(&init_mm, current);
1542 
1543 #ifdef CONFIG_MIPS_MT_SMTC
1544 	if (bootTC) {
1545 #endif /* CONFIG_MIPS_MT_SMTC */
1546 		cpu_cache_init();
1547 		tlb_init();
1548 #ifdef CONFIG_MIPS_MT_SMTC
1549 	} else if (!secondaryTC) {
1550 		/*
1551 		 * First TC in non-boot VPE must do subset of tlb_init()
1552 		 * for MMU countrol registers.
1553 		 */
1554 		write_c0_pagemask(PM_DEFAULT_MASK);
1555 		write_c0_wired(0);
1556 	}
1557 #endif /* CONFIG_MIPS_MT_SMTC */
1558 }
1559 
1560 /* Install CPU exception handler */
1561 void __init set_handler(unsigned long offset, void *addr, unsigned long size)
1562 {
1563 	memcpy((void *)(ebase + offset), addr, size);
1564 	local_flush_icache_range(ebase + offset, ebase + offset + size);
1565 }
1566 
1567 static char panic_null_cerr[] __cpuinitdata =
1568 	"Trying to set NULL cache error exception handler";
1569 
1570 /*
1571  * Install uncached CPU exception handler.
1572  * This is suitable only for the cache error exception which is the only
1573  * exception handler that is being run uncached.
1574  */
1575 void __cpuinit set_uncached_handler(unsigned long offset, void *addr,
1576 	unsigned long size)
1577 {
1578 	unsigned long uncached_ebase = CKSEG1ADDR(ebase);
1579 
1580 	if (!addr)
1581 		panic(panic_null_cerr);
1582 
1583 	memcpy((void *)(uncached_ebase + offset), addr, size);
1584 }
1585 
1586 static int __initdata rdhwr_noopt;
1587 static int __init set_rdhwr_noopt(char *str)
1588 {
1589 	rdhwr_noopt = 1;
1590 	return 1;
1591 }
1592 
1593 __setup("rdhwr_noopt", set_rdhwr_noopt);
1594 
1595 void __init trap_init(void)
1596 {
1597 	extern char except_vec3_generic, except_vec3_r4000;
1598 	extern char except_vec4;
1599 	unsigned long i;
1600 	int rollback;
1601 
1602 	check_wait();
1603 	rollback = (cpu_wait == r4k_wait);
1604 
1605 #if defined(CONFIG_KGDB)
1606 	if (kgdb_early_setup)
1607 		return;	/* Already done */
1608 #endif
1609 
1610 	if (cpu_has_veic || cpu_has_vint) {
1611 		unsigned long size = 0x200 + VECTORSPACING*64;
1612 		ebase = (unsigned long)
1613 			__alloc_bootmem(size, 1 << fls(size), 0);
1614 	} else {
1615 		ebase = CKSEG0;
1616 		if (cpu_has_mips_r2)
1617 			ebase += (read_c0_ebase() & 0x3ffff000);
1618 	}
1619 
1620 	per_cpu_trap_init();
1621 
1622 	/*
1623 	 * Copy the generic exception handlers to their final destination.
1624 	 * This will be overriden later as suitable for a particular
1625 	 * configuration.
1626 	 */
1627 	set_handler(0x180, &except_vec3_generic, 0x80);
1628 
1629 	/*
1630 	 * Setup default vectors
1631 	 */
1632 	for (i = 0; i <= 31; i++)
1633 		set_except_vector(i, handle_reserved);
1634 
1635 	/*
1636 	 * Copy the EJTAG debug exception vector handler code to it's final
1637 	 * destination.
1638 	 */
1639 	if (cpu_has_ejtag && board_ejtag_handler_setup)
1640 		board_ejtag_handler_setup();
1641 
1642 	/*
1643 	 * Only some CPUs have the watch exceptions.
1644 	 */
1645 	if (cpu_has_watch)
1646 		set_except_vector(23, handle_watch);
1647 
1648 	/*
1649 	 * Initialise interrupt handlers
1650 	 */
1651 	if (cpu_has_veic || cpu_has_vint) {
1652 		int nvec = cpu_has_veic ? 64 : 8;
1653 		for (i = 0; i < nvec; i++)
1654 			set_vi_handler(i, NULL);
1655 	}
1656 	else if (cpu_has_divec)
1657 		set_handler(0x200, &except_vec4, 0x8);
1658 
1659 	/*
1660 	 * Some CPUs can enable/disable for cache parity detection, but does
1661 	 * it different ways.
1662 	 */
1663 	parity_protection_init();
1664 
1665 	/*
1666 	 * The Data Bus Errors / Instruction Bus Errors are signaled
1667 	 * by external hardware.  Therefore these two exceptions
1668 	 * may have board specific handlers.
1669 	 */
1670 	if (board_be_init)
1671 		board_be_init();
1672 
1673 	set_except_vector(0, rollback ? rollback_handle_int : handle_int);
1674 	set_except_vector(1, handle_tlbm);
1675 	set_except_vector(2, handle_tlbl);
1676 	set_except_vector(3, handle_tlbs);
1677 
1678 	set_except_vector(4, handle_adel);
1679 	set_except_vector(5, handle_ades);
1680 
1681 	set_except_vector(6, handle_ibe);
1682 	set_except_vector(7, handle_dbe);
1683 
1684 	set_except_vector(8, handle_sys);
1685 	set_except_vector(9, handle_bp);
1686 	set_except_vector(10, rdhwr_noopt ? handle_ri :
1687 			  (cpu_has_vtag_icache ?
1688 			   handle_ri_rdhwr_vivt : handle_ri_rdhwr));
1689 	set_except_vector(11, handle_cpu);
1690 	set_except_vector(12, handle_ov);
1691 	set_except_vector(13, handle_tr);
1692 
1693 	if (current_cpu_type() == CPU_R6000 ||
1694 	    current_cpu_type() == CPU_R6000A) {
1695 		/*
1696 		 * The R6000 is the only R-series CPU that features a machine
1697 		 * check exception (similar to the R4000 cache error) and
1698 		 * unaligned ldc1/sdc1 exception.  The handlers have not been
1699 		 * written yet.  Well, anyway there is no R6000 machine on the
1700 		 * current list of targets for Linux/MIPS.
1701 		 * (Duh, crap, there is someone with a triple R6k machine)
1702 		 */
1703 		//set_except_vector(14, handle_mc);
1704 		//set_except_vector(15, handle_ndc);
1705 	}
1706 
1707 
1708 	if (board_nmi_handler_setup)
1709 		board_nmi_handler_setup();
1710 
1711 	if (cpu_has_fpu && !cpu_has_nofpuex)
1712 		set_except_vector(15, handle_fpe);
1713 
1714 	set_except_vector(22, handle_mdmx);
1715 
1716 	if (cpu_has_mcheck)
1717 		set_except_vector(24, handle_mcheck);
1718 
1719 	if (cpu_has_mipsmt)
1720 		set_except_vector(25, handle_mt);
1721 
1722 	set_except_vector(26, handle_dsp);
1723 
1724 	if (cpu_has_vce)
1725 		/* Special exception: R4[04]00 uses also the divec space. */
1726 		memcpy((void *)(ebase + 0x180), &except_vec3_r4000, 0x100);
1727 	else if (cpu_has_4kex)
1728 		memcpy((void *)(ebase + 0x180), &except_vec3_generic, 0x80);
1729 	else
1730 		memcpy((void *)(ebase + 0x080), &except_vec3_generic, 0x80);
1731 
1732 	local_flush_icache_range(ebase, ebase + 0x400);
1733 	flush_tlb_handlers();
1734 
1735 	sort_extable(__start___dbe_table, __stop___dbe_table);
1736 
1737 	register_cu2_notifier(&default_cu2_notifier);
1738 }
1739