xref: /linux/arch/mips/kernel/traps.c (revision 367b8112fe2ea5c39a7bb4d263dcdd9b612fae18)
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 
29 #include <asm/bootinfo.h>
30 #include <asm/branch.h>
31 #include <asm/break.h>
32 #include <asm/cpu.h>
33 #include <asm/dsp.h>
34 #include <asm/fpu.h>
35 #include <asm/fpu_emulator.h>
36 #include <asm/mipsregs.h>
37 #include <asm/mipsmtregs.h>
38 #include <asm/module.h>
39 #include <asm/pgtable.h>
40 #include <asm/ptrace.h>
41 #include <asm/sections.h>
42 #include <asm/system.h>
43 #include <asm/tlbdebug.h>
44 #include <asm/traps.h>
45 #include <asm/uaccess.h>
46 #include <asm/watch.h>
47 #include <asm/mmu_context.h>
48 #include <asm/types.h>
49 #include <asm/stacktrace.h>
50 
51 extern void check_wait(void);
52 extern asmlinkage void r4k_wait(void);
53 extern asmlinkage void rollback_handle_int(void);
54 extern asmlinkage void handle_int(void);
55 extern asmlinkage void handle_tlbm(void);
56 extern asmlinkage void handle_tlbl(void);
57 extern asmlinkage void handle_tlbs(void);
58 extern asmlinkage void handle_adel(void);
59 extern asmlinkage void handle_ades(void);
60 extern asmlinkage void handle_ibe(void);
61 extern asmlinkage void handle_dbe(void);
62 extern asmlinkage void handle_sys(void);
63 extern asmlinkage void handle_bp(void);
64 extern asmlinkage void handle_ri(void);
65 extern asmlinkage void handle_ri_rdhwr_vivt(void);
66 extern asmlinkage void handle_ri_rdhwr(void);
67 extern asmlinkage void handle_cpu(void);
68 extern asmlinkage void handle_ov(void);
69 extern asmlinkage void handle_tr(void);
70 extern asmlinkage void handle_fpe(void);
71 extern asmlinkage void handle_mdmx(void);
72 extern asmlinkage void handle_watch(void);
73 extern asmlinkage void handle_mt(void);
74 extern asmlinkage void handle_dsp(void);
75 extern asmlinkage void handle_mcheck(void);
76 extern asmlinkage void handle_reserved(void);
77 
78 extern int fpu_emulator_cop1Handler(struct pt_regs *xcp,
79 	struct mips_fpu_struct *ctx, int has_fpu);
80 
81 void (*board_be_init)(void);
82 int (*board_be_handler)(struct pt_regs *regs, int is_fixup);
83 void (*board_nmi_handler_setup)(void);
84 void (*board_ejtag_handler_setup)(void);
85 void (*board_bind_eic_interrupt)(int irq, int regset);
86 
87 
88 static void show_raw_backtrace(unsigned long reg29)
89 {
90 	unsigned long *sp = (unsigned long *)(reg29 & ~3);
91 	unsigned long addr;
92 
93 	printk("Call Trace:");
94 #ifdef CONFIG_KALLSYMS
95 	printk("\n");
96 #endif
97 	while (!kstack_end(sp)) {
98 		unsigned long __user *p =
99 			(unsigned long __user *)(unsigned long)sp++;
100 		if (__get_user(addr, p)) {
101 			printk(" (Bad stack address)");
102 			break;
103 		}
104 		if (__kernel_text_address(addr))
105 			print_ip_sym(addr);
106 	}
107 	printk("\n");
108 }
109 
110 #ifdef CONFIG_KALLSYMS
111 int raw_show_trace;
112 static int __init set_raw_show_trace(char *str)
113 {
114 	raw_show_trace = 1;
115 	return 1;
116 }
117 __setup("raw_show_trace", set_raw_show_trace);
118 #endif
119 
120 static void show_backtrace(struct task_struct *task, const struct pt_regs *regs)
121 {
122 	unsigned long sp = regs->regs[29];
123 	unsigned long ra = regs->regs[31];
124 	unsigned long pc = regs->cp0_epc;
125 
126 	if (raw_show_trace || !__kernel_text_address(pc)) {
127 		show_raw_backtrace(sp);
128 		return;
129 	}
130 	printk("Call Trace:\n");
131 	do {
132 		print_ip_sym(pc);
133 		pc = unwind_stack(task, &sp, pc, &ra);
134 	} while (pc);
135 	printk("\n");
136 }
137 
138 /*
139  * This routine abuses get_user()/put_user() to reference pointers
140  * with at least a bit of error checking ...
141  */
142 static void show_stacktrace(struct task_struct *task,
143 	const struct pt_regs *regs)
144 {
145 	const int field = 2 * sizeof(unsigned long);
146 	long stackdata;
147 	int i;
148 	unsigned long __user *sp = (unsigned long __user *)regs->regs[29];
149 
150 	printk("Stack :");
151 	i = 0;
152 	while ((unsigned long) sp & (PAGE_SIZE - 1)) {
153 		if (i && ((i % (64 / field)) == 0))
154 			printk("\n       ");
155 		if (i > 39) {
156 			printk(" ...");
157 			break;
158 		}
159 
160 		if (__get_user(stackdata, sp++)) {
161 			printk(" (Bad stack address)");
162 			break;
163 		}
164 
165 		printk(" %0*lx", field, stackdata);
166 		i++;
167 	}
168 	printk("\n");
169 	show_backtrace(task, regs);
170 }
171 
172 void show_stack(struct task_struct *task, unsigned long *sp)
173 {
174 	struct pt_regs regs;
175 	if (sp) {
176 		regs.regs[29] = (unsigned long)sp;
177 		regs.regs[31] = 0;
178 		regs.cp0_epc = 0;
179 	} else {
180 		if (task && task != current) {
181 			regs.regs[29] = task->thread.reg29;
182 			regs.regs[31] = 0;
183 			regs.cp0_epc = task->thread.reg31;
184 		} else {
185 			prepare_frametrace(&regs);
186 		}
187 	}
188 	show_stacktrace(task, &regs);
189 }
190 
191 /*
192  * The architecture-independent dump_stack generator
193  */
194 void dump_stack(void)
195 {
196 	struct pt_regs regs;
197 
198 	prepare_frametrace(&regs);
199 	show_backtrace(current, &regs);
200 }
201 
202 EXPORT_SYMBOL(dump_stack);
203 
204 static void show_code(unsigned int __user *pc)
205 {
206 	long i;
207 	unsigned short __user *pc16 = NULL;
208 
209 	printk("\nCode:");
210 
211 	if ((unsigned long)pc & 1)
212 		pc16 = (unsigned short __user *)((unsigned long)pc & ~1);
213 	for(i = -3 ; i < 6 ; i++) {
214 		unsigned int insn;
215 		if (pc16 ? __get_user(insn, pc16 + i) : __get_user(insn, pc + i)) {
216 			printk(" (Bad address in epc)\n");
217 			break;
218 		}
219 		printk("%c%0*x%c", (i?' ':'<'), pc16 ? 4 : 8, insn, (i?' ':'>'));
220 	}
221 }
222 
223 static void __show_regs(const struct pt_regs *regs)
224 {
225 	const int field = 2 * sizeof(unsigned long);
226 	unsigned int cause = regs->cp0_cause;
227 	int i;
228 
229 	printk("Cpu %d\n", smp_processor_id());
230 
231 	/*
232 	 * Saved main processor registers
233 	 */
234 	for (i = 0; i < 32; ) {
235 		if ((i % 4) == 0)
236 			printk("$%2d   :", i);
237 		if (i == 0)
238 			printk(" %0*lx", field, 0UL);
239 		else if (i == 26 || i == 27)
240 			printk(" %*s", field, "");
241 		else
242 			printk(" %0*lx", field, regs->regs[i]);
243 
244 		i++;
245 		if ((i % 4) == 0)
246 			printk("\n");
247 	}
248 
249 #ifdef CONFIG_CPU_HAS_SMARTMIPS
250 	printk("Acx    : %0*lx\n", field, regs->acx);
251 #endif
252 	printk("Hi    : %0*lx\n", field, regs->hi);
253 	printk("Lo    : %0*lx\n", field, regs->lo);
254 
255 	/*
256 	 * Saved cp0 registers
257 	 */
258 	printk("epc   : %0*lx %pS\n", field, regs->cp0_epc,
259 	       (void *) regs->cp0_epc);
260 	printk("    %s\n", print_tainted());
261 	printk("ra    : %0*lx %pS\n", field, regs->regs[31],
262 	       (void *) regs->regs[31]);
263 
264 	printk("Status: %08x    ", (uint32_t) regs->cp0_status);
265 
266 	if (current_cpu_data.isa_level == MIPS_CPU_ISA_I) {
267 		if (regs->cp0_status & ST0_KUO)
268 			printk("KUo ");
269 		if (regs->cp0_status & ST0_IEO)
270 			printk("IEo ");
271 		if (regs->cp0_status & ST0_KUP)
272 			printk("KUp ");
273 		if (regs->cp0_status & ST0_IEP)
274 			printk("IEp ");
275 		if (regs->cp0_status & ST0_KUC)
276 			printk("KUc ");
277 		if (regs->cp0_status & ST0_IEC)
278 			printk("IEc ");
279 	} else {
280 		if (regs->cp0_status & ST0_KX)
281 			printk("KX ");
282 		if (regs->cp0_status & ST0_SX)
283 			printk("SX ");
284 		if (regs->cp0_status & ST0_UX)
285 			printk("UX ");
286 		switch (regs->cp0_status & ST0_KSU) {
287 		case KSU_USER:
288 			printk("USER ");
289 			break;
290 		case KSU_SUPERVISOR:
291 			printk("SUPERVISOR ");
292 			break;
293 		case KSU_KERNEL:
294 			printk("KERNEL ");
295 			break;
296 		default:
297 			printk("BAD_MODE ");
298 			break;
299 		}
300 		if (regs->cp0_status & ST0_ERL)
301 			printk("ERL ");
302 		if (regs->cp0_status & ST0_EXL)
303 			printk("EXL ");
304 		if (regs->cp0_status & ST0_IE)
305 			printk("IE ");
306 	}
307 	printk("\n");
308 
309 	printk("Cause : %08x\n", cause);
310 
311 	cause = (cause & CAUSEF_EXCCODE) >> CAUSEB_EXCCODE;
312 	if (1 <= cause && cause <= 5)
313 		printk("BadVA : %0*lx\n", field, regs->cp0_badvaddr);
314 
315 	printk("PrId  : %08x (%s)\n", read_c0_prid(),
316 	       cpu_name_string());
317 }
318 
319 /*
320  * FIXME: really the generic show_regs should take a const pointer argument.
321  */
322 void show_regs(struct pt_regs *regs)
323 {
324 	__show_regs((struct pt_regs *)regs);
325 }
326 
327 void show_registers(const struct pt_regs *regs)
328 {
329 	const int field = 2 * sizeof(unsigned long);
330 
331 	__show_regs(regs);
332 	print_modules();
333 	printk("Process %s (pid: %d, threadinfo=%p, task=%p, tls=%0*lx)\n",
334 	       current->comm, current->pid, current_thread_info(), current,
335 	      field, current_thread_info()->tp_value);
336 	if (cpu_has_userlocal) {
337 		unsigned long tls;
338 
339 		tls = read_c0_userlocal();
340 		if (tls != current_thread_info()->tp_value)
341 			printk("*HwTLS: %0*lx\n", field, tls);
342 	}
343 
344 	show_stacktrace(current, regs);
345 	show_code((unsigned int __user *) regs->cp0_epc);
346 	printk("\n");
347 }
348 
349 static DEFINE_SPINLOCK(die_lock);
350 
351 void __noreturn die(const char * str, const struct pt_regs * regs)
352 {
353 	static int die_counter;
354 #ifdef CONFIG_MIPS_MT_SMTC
355 	unsigned long dvpret = dvpe();
356 #endif /* CONFIG_MIPS_MT_SMTC */
357 
358 	console_verbose();
359 	spin_lock_irq(&die_lock);
360 	bust_spinlocks(1);
361 #ifdef CONFIG_MIPS_MT_SMTC
362 	mips_mt_regdump(dvpret);
363 #endif /* CONFIG_MIPS_MT_SMTC */
364 	printk("%s[#%d]:\n", str, ++die_counter);
365 	show_registers(regs);
366 	add_taint(TAINT_DIE);
367 	spin_unlock_irq(&die_lock);
368 
369 	if (in_interrupt())
370 		panic("Fatal exception in interrupt");
371 
372 	if (panic_on_oops) {
373 		printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
374 		ssleep(5);
375 		panic("Fatal exception");
376 	}
377 
378 	do_exit(SIGSEGV);
379 }
380 
381 extern struct exception_table_entry __start___dbe_table[];
382 extern struct exception_table_entry __stop___dbe_table[];
383 
384 __asm__(
385 "	.section	__dbe_table, \"a\"\n"
386 "	.previous			\n");
387 
388 /* Given an address, look for it in the exception tables. */
389 static const struct exception_table_entry *search_dbe_tables(unsigned long addr)
390 {
391 	const struct exception_table_entry *e;
392 
393 	e = search_extable(__start___dbe_table, __stop___dbe_table - 1, addr);
394 	if (!e)
395 		e = search_module_dbetables(addr);
396 	return e;
397 }
398 
399 asmlinkage void do_be(struct pt_regs *regs)
400 {
401 	const int field = 2 * sizeof(unsigned long);
402 	const struct exception_table_entry *fixup = NULL;
403 	int data = regs->cp0_cause & 4;
404 	int action = MIPS_BE_FATAL;
405 
406 	/* XXX For now.  Fixme, this searches the wrong table ...  */
407 	if (data && !user_mode(regs))
408 		fixup = search_dbe_tables(exception_epc(regs));
409 
410 	if (fixup)
411 		action = MIPS_BE_FIXUP;
412 
413 	if (board_be_handler)
414 		action = board_be_handler(regs, fixup != NULL);
415 
416 	switch (action) {
417 	case MIPS_BE_DISCARD:
418 		return;
419 	case MIPS_BE_FIXUP:
420 		if (fixup) {
421 			regs->cp0_epc = fixup->nextinsn;
422 			return;
423 		}
424 		break;
425 	default:
426 		break;
427 	}
428 
429 	/*
430 	 * Assume it would be too dangerous to continue ...
431 	 */
432 	printk(KERN_ALERT "%s bus error, epc == %0*lx, ra == %0*lx\n",
433 	       data ? "Data" : "Instruction",
434 	       field, regs->cp0_epc, field, regs->regs[31]);
435 	if (notify_die(DIE_OOPS, "bus error", regs, SIGBUS, 0, 0)
436 	    == NOTIFY_STOP)
437 		return;
438 
439 	die_if_kernel("Oops", regs);
440 	force_sig(SIGBUS, current);
441 }
442 
443 /*
444  * ll/sc, rdhwr, sync emulation
445  */
446 
447 #define OPCODE 0xfc000000
448 #define BASE   0x03e00000
449 #define RT     0x001f0000
450 #define OFFSET 0x0000ffff
451 #define LL     0xc0000000
452 #define SC     0xe0000000
453 #define SPEC0  0x00000000
454 #define SPEC3  0x7c000000
455 #define RD     0x0000f800
456 #define FUNC   0x0000003f
457 #define SYNC   0x0000000f
458 #define RDHWR  0x0000003b
459 
460 /*
461  * The ll_bit is cleared by r*_switch.S
462  */
463 
464 unsigned long ll_bit;
465 
466 static struct task_struct *ll_task = NULL;
467 
468 static inline int simulate_ll(struct pt_regs *regs, unsigned int opcode)
469 {
470 	unsigned long value, __user *vaddr;
471 	long offset;
472 
473 	/*
474 	 * analyse the ll instruction that just caused a ri exception
475 	 * and put the referenced address to addr.
476 	 */
477 
478 	/* sign extend offset */
479 	offset = opcode & OFFSET;
480 	offset <<= 16;
481 	offset >>= 16;
482 
483 	vaddr = (unsigned long __user *)
484 	        ((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
485 
486 	if ((unsigned long)vaddr & 3)
487 		return SIGBUS;
488 	if (get_user(value, vaddr))
489 		return SIGSEGV;
490 
491 	preempt_disable();
492 
493 	if (ll_task == NULL || ll_task == current) {
494 		ll_bit = 1;
495 	} else {
496 		ll_bit = 0;
497 	}
498 	ll_task = current;
499 
500 	preempt_enable();
501 
502 	regs->regs[(opcode & RT) >> 16] = value;
503 
504 	return 0;
505 }
506 
507 static inline int simulate_sc(struct pt_regs *regs, unsigned int opcode)
508 {
509 	unsigned long __user *vaddr;
510 	unsigned long reg;
511 	long offset;
512 
513 	/*
514 	 * analyse the sc instruction that just caused a ri exception
515 	 * and put the referenced address to addr.
516 	 */
517 
518 	/* sign extend offset */
519 	offset = opcode & OFFSET;
520 	offset <<= 16;
521 	offset >>= 16;
522 
523 	vaddr = (unsigned long __user *)
524 	        ((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
525 	reg = (opcode & RT) >> 16;
526 
527 	if ((unsigned long)vaddr & 3)
528 		return SIGBUS;
529 
530 	preempt_disable();
531 
532 	if (ll_bit == 0 || ll_task != current) {
533 		regs->regs[reg] = 0;
534 		preempt_enable();
535 		return 0;
536 	}
537 
538 	preempt_enable();
539 
540 	if (put_user(regs->regs[reg], vaddr))
541 		return SIGSEGV;
542 
543 	regs->regs[reg] = 1;
544 
545 	return 0;
546 }
547 
548 /*
549  * ll uses the opcode of lwc0 and sc uses the opcode of swc0.  That is both
550  * opcodes are supposed to result in coprocessor unusable exceptions if
551  * executed on ll/sc-less processors.  That's the theory.  In practice a
552  * few processors such as NEC's VR4100 throw reserved instruction exceptions
553  * instead, so we're doing the emulation thing in both exception handlers.
554  */
555 static int simulate_llsc(struct pt_regs *regs, unsigned int opcode)
556 {
557 	if ((opcode & OPCODE) == LL)
558 		return simulate_ll(regs, opcode);
559 	if ((opcode & OPCODE) == SC)
560 		return simulate_sc(regs, opcode);
561 
562 	return -1;			/* Must be something else ... */
563 }
564 
565 /*
566  * Simulate trapping 'rdhwr' instructions to provide user accessible
567  * registers not implemented in hardware.
568  */
569 static int simulate_rdhwr(struct pt_regs *regs, unsigned int opcode)
570 {
571 	struct thread_info *ti = task_thread_info(current);
572 
573 	if ((opcode & OPCODE) == SPEC3 && (opcode & FUNC) == RDHWR) {
574 		int rd = (opcode & RD) >> 11;
575 		int rt = (opcode & RT) >> 16;
576 		switch (rd) {
577 		case 0:		/* CPU number */
578 			regs->regs[rt] = smp_processor_id();
579 			return 0;
580 		case 1:		/* SYNCI length */
581 			regs->regs[rt] = min(current_cpu_data.dcache.linesz,
582 					     current_cpu_data.icache.linesz);
583 			return 0;
584 		case 2:		/* Read count register */
585 			regs->regs[rt] = read_c0_count();
586 			return 0;
587 		case 3:		/* Count register resolution */
588 			switch (current_cpu_data.cputype) {
589 			case CPU_20KC:
590 			case CPU_25KF:
591 				regs->regs[rt] = 1;
592 				break;
593 			default:
594 				regs->regs[rt] = 2;
595 			}
596 			return 0;
597 		case 29:
598 			regs->regs[rt] = ti->tp_value;
599 			return 0;
600 		default:
601 			return -1;
602 		}
603 	}
604 
605 	/* Not ours.  */
606 	return -1;
607 }
608 
609 static int simulate_sync(struct pt_regs *regs, unsigned int opcode)
610 {
611 	if ((opcode & OPCODE) == SPEC0 && (opcode & FUNC) == SYNC)
612 		return 0;
613 
614 	return -1;			/* Must be something else ... */
615 }
616 
617 asmlinkage void do_ov(struct pt_regs *regs)
618 {
619 	siginfo_t info;
620 
621 	die_if_kernel("Integer overflow", regs);
622 
623 	info.si_code = FPE_INTOVF;
624 	info.si_signo = SIGFPE;
625 	info.si_errno = 0;
626 	info.si_addr = (void __user *) regs->cp0_epc;
627 	force_sig_info(SIGFPE, &info, current);
628 }
629 
630 /*
631  * XXX Delayed fp exceptions when doing a lazy ctx switch XXX
632  */
633 asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
634 {
635 	siginfo_t info;
636 
637 	if (notify_die(DIE_FP, "FP exception", regs, SIGFPE, 0, 0)
638 	    == NOTIFY_STOP)
639 		return;
640 	die_if_kernel("FP exception in kernel code", regs);
641 
642 	if (fcr31 & FPU_CSR_UNI_X) {
643 		int sig;
644 
645 		/*
646 		 * Unimplemented operation exception.  If we've got the full
647 		 * software emulator on-board, let's use it...
648 		 *
649 		 * Force FPU to dump state into task/thread context.  We're
650 		 * moving a lot of data here for what is probably a single
651 		 * instruction, but the alternative is to pre-decode the FP
652 		 * register operands before invoking the emulator, which seems
653 		 * a bit extreme for what should be an infrequent event.
654 		 */
655 		/* Ensure 'resume' not overwrite saved fp context again. */
656 		lose_fpu(1);
657 
658 		/* Run the emulator */
659 		sig = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1);
660 
661 		/*
662 		 * We can't allow the emulated instruction to leave any of
663 		 * the cause bit set in $fcr31.
664 		 */
665 		current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
666 
667 		/* Restore the hardware register state */
668 		own_fpu(1);	/* Using the FPU again.  */
669 
670 		/* If something went wrong, signal */
671 		if (sig)
672 			force_sig(sig, current);
673 
674 		return;
675 	} else if (fcr31 & FPU_CSR_INV_X)
676 		info.si_code = FPE_FLTINV;
677 	else if (fcr31 & FPU_CSR_DIV_X)
678 		info.si_code = FPE_FLTDIV;
679 	else if (fcr31 & FPU_CSR_OVF_X)
680 		info.si_code = FPE_FLTOVF;
681 	else if (fcr31 & FPU_CSR_UDF_X)
682 		info.si_code = FPE_FLTUND;
683 	else if (fcr31 & FPU_CSR_INE_X)
684 		info.si_code = FPE_FLTRES;
685 	else
686 		info.si_code = __SI_FAULT;
687 	info.si_signo = SIGFPE;
688 	info.si_errno = 0;
689 	info.si_addr = (void __user *) regs->cp0_epc;
690 	force_sig_info(SIGFPE, &info, current);
691 }
692 
693 static void do_trap_or_bp(struct pt_regs *regs, unsigned int code,
694 	const char *str)
695 {
696 	siginfo_t info;
697 	char b[40];
698 
699 	if (notify_die(DIE_TRAP, str, regs, code, 0, 0) == NOTIFY_STOP)
700 		return;
701 
702 	/*
703 	 * A short test says that IRIX 5.3 sends SIGTRAP for all trap
704 	 * insns, even for trap and break codes that indicate arithmetic
705 	 * failures.  Weird ...
706 	 * But should we continue the brokenness???  --macro
707 	 */
708 	switch (code) {
709 	case BRK_OVERFLOW:
710 	case BRK_DIVZERO:
711 		scnprintf(b, sizeof(b), "%s instruction in kernel code", str);
712 		die_if_kernel(b, regs);
713 		if (code == BRK_DIVZERO)
714 			info.si_code = FPE_INTDIV;
715 		else
716 			info.si_code = FPE_INTOVF;
717 		info.si_signo = SIGFPE;
718 		info.si_errno = 0;
719 		info.si_addr = (void __user *) regs->cp0_epc;
720 		force_sig_info(SIGFPE, &info, current);
721 		break;
722 	case BRK_BUG:
723 		die_if_kernel("Kernel bug detected", regs);
724 		force_sig(SIGTRAP, current);
725 		break;
726 	case BRK_MEMU:
727 		/*
728 		 * Address errors may be deliberately induced by the FPU
729 		 * emulator to retake control of the CPU after executing the
730 		 * instruction in the delay slot of an emulated branch.
731 		 *
732 		 * Terminate if exception was recognized as a delay slot return
733 		 * otherwise handle as normal.
734 		 */
735 		if (do_dsemulret(regs))
736 			return;
737 
738 		die_if_kernel("Math emu break/trap", regs);
739 		force_sig(SIGTRAP, current);
740 		break;
741 	default:
742 		scnprintf(b, sizeof(b), "%s instruction in kernel code", str);
743 		die_if_kernel(b, regs);
744 		force_sig(SIGTRAP, current);
745 	}
746 }
747 
748 asmlinkage void do_bp(struct pt_regs *regs)
749 {
750 	unsigned int opcode, bcode;
751 
752 	if (__get_user(opcode, (unsigned int __user *) exception_epc(regs)))
753 		goto out_sigsegv;
754 
755 	/*
756 	 * There is the ancient bug in the MIPS assemblers that the break
757 	 * code starts left to bit 16 instead to bit 6 in the opcode.
758 	 * Gas is bug-compatible, but not always, grrr...
759 	 * We handle both cases with a simple heuristics.  --macro
760 	 */
761 	bcode = ((opcode >> 6) & ((1 << 20) - 1));
762 	if (bcode >= (1 << 10))
763 		bcode >>= 10;
764 
765 	do_trap_or_bp(regs, bcode, "Break");
766 	return;
767 
768 out_sigsegv:
769 	force_sig(SIGSEGV, current);
770 }
771 
772 asmlinkage void do_tr(struct pt_regs *regs)
773 {
774 	unsigned int opcode, tcode = 0;
775 
776 	if (__get_user(opcode, (unsigned int __user *) exception_epc(regs)))
777 		goto out_sigsegv;
778 
779 	/* Immediate versions don't provide a code.  */
780 	if (!(opcode & OPCODE))
781 		tcode = ((opcode >> 6) & ((1 << 10) - 1));
782 
783 	do_trap_or_bp(regs, tcode, "Trap");
784 	return;
785 
786 out_sigsegv:
787 	force_sig(SIGSEGV, current);
788 }
789 
790 asmlinkage void do_ri(struct pt_regs *regs)
791 {
792 	unsigned int __user *epc = (unsigned int __user *)exception_epc(regs);
793 	unsigned long old_epc = regs->cp0_epc;
794 	unsigned int opcode = 0;
795 	int status = -1;
796 
797 	if (notify_die(DIE_RI, "RI Fault", regs, SIGSEGV, 0, 0)
798 	    == NOTIFY_STOP)
799 		return;
800 
801 	die_if_kernel("Reserved instruction in kernel code", regs);
802 
803 	if (unlikely(compute_return_epc(regs) < 0))
804 		return;
805 
806 	if (unlikely(get_user(opcode, epc) < 0))
807 		status = SIGSEGV;
808 
809 	if (!cpu_has_llsc && status < 0)
810 		status = simulate_llsc(regs, opcode);
811 
812 	if (status < 0)
813 		status = simulate_rdhwr(regs, opcode);
814 
815 	if (status < 0)
816 		status = simulate_sync(regs, opcode);
817 
818 	if (status < 0)
819 		status = SIGILL;
820 
821 	if (unlikely(status > 0)) {
822 		regs->cp0_epc = old_epc;		/* Undo skip-over.  */
823 		force_sig(status, current);
824 	}
825 }
826 
827 /*
828  * MIPS MT processors may have fewer FPU contexts than CPU threads. If we've
829  * emulated more than some threshold number of instructions, force migration to
830  * a "CPU" that has FP support.
831  */
832 static void mt_ase_fp_affinity(void)
833 {
834 #ifdef CONFIG_MIPS_MT_FPAFF
835 	if (mt_fpemul_threshold > 0 &&
836 	     ((current->thread.emulated_fp++ > mt_fpemul_threshold))) {
837 		/*
838 		 * If there's no FPU present, or if the application has already
839 		 * restricted the allowed set to exclude any CPUs with FPUs,
840 		 * we'll skip the procedure.
841 		 */
842 		if (cpus_intersects(current->cpus_allowed, mt_fpu_cpumask)) {
843 			cpumask_t tmask;
844 
845 			current->thread.user_cpus_allowed
846 				= current->cpus_allowed;
847 			cpus_and(tmask, current->cpus_allowed,
848 				mt_fpu_cpumask);
849 			set_cpus_allowed(current, tmask);
850 			set_thread_flag(TIF_FPUBOUND);
851 		}
852 	}
853 #endif /* CONFIG_MIPS_MT_FPAFF */
854 }
855 
856 asmlinkage void do_cpu(struct pt_regs *regs)
857 {
858 	unsigned int __user *epc;
859 	unsigned long old_epc;
860 	unsigned int opcode;
861 	unsigned int cpid;
862 	int status;
863 
864 	die_if_kernel("do_cpu invoked from kernel context!", regs);
865 
866 	cpid = (regs->cp0_cause >> CAUSEB_CE) & 3;
867 
868 	switch (cpid) {
869 	case 0:
870 		epc = (unsigned int __user *)exception_epc(regs);
871 		old_epc = regs->cp0_epc;
872 		opcode = 0;
873 		status = -1;
874 
875 		if (unlikely(compute_return_epc(regs) < 0))
876 			return;
877 
878 		if (unlikely(get_user(opcode, epc) < 0))
879 			status = SIGSEGV;
880 
881 		if (!cpu_has_llsc && status < 0)
882 			status = simulate_llsc(regs, opcode);
883 
884 		if (status < 0)
885 			status = simulate_rdhwr(regs, opcode);
886 
887 		if (status < 0)
888 			status = SIGILL;
889 
890 		if (unlikely(status > 0)) {
891 			regs->cp0_epc = old_epc;	/* Undo skip-over.  */
892 			force_sig(status, current);
893 		}
894 
895 		return;
896 
897 	case 1:
898 		if (used_math())	/* Using the FPU again.  */
899 			own_fpu(1);
900 		else {			/* First time FPU user.  */
901 			init_fpu();
902 			set_used_math();
903 		}
904 
905 		if (!raw_cpu_has_fpu) {
906 			int sig;
907 			sig = fpu_emulator_cop1Handler(regs,
908 						&current->thread.fpu, 0);
909 			if (sig)
910 				force_sig(sig, current);
911 			else
912 				mt_ase_fp_affinity();
913 		}
914 
915 		return;
916 
917 	case 2:
918 	case 3:
919 		break;
920 	}
921 
922 	force_sig(SIGILL, current);
923 }
924 
925 asmlinkage void do_mdmx(struct pt_regs *regs)
926 {
927 	force_sig(SIGILL, current);
928 }
929 
930 asmlinkage void do_watch(struct pt_regs *regs)
931 {
932 	u32 cause;
933 
934 	/*
935 	 * Clear WP (bit 22) bit of cause register so we don't loop
936 	 * forever.
937 	 */
938 	cause = read_c0_cause();
939 	cause &= ~(1 << 22);
940 	write_c0_cause(cause);
941 
942 	/*
943 	 * If the current thread has the watch registers loaded, save
944 	 * their values and send SIGTRAP.  Otherwise another thread
945 	 * left the registers set, clear them and continue.
946 	 */
947 	if (test_tsk_thread_flag(current, TIF_LOAD_WATCH)) {
948 		mips_read_watch_registers();
949 		force_sig(SIGTRAP, current);
950 	} else
951 		mips_clear_watch_registers();
952 }
953 
954 asmlinkage void do_mcheck(struct pt_regs *regs)
955 {
956 	const int field = 2 * sizeof(unsigned long);
957 	int multi_match = regs->cp0_status & ST0_TS;
958 
959 	show_regs(regs);
960 
961 	if (multi_match) {
962 		printk("Index   : %0x\n", read_c0_index());
963 		printk("Pagemask: %0x\n", read_c0_pagemask());
964 		printk("EntryHi : %0*lx\n", field, read_c0_entryhi());
965 		printk("EntryLo0: %0*lx\n", field, read_c0_entrylo0());
966 		printk("EntryLo1: %0*lx\n", field, read_c0_entrylo1());
967 		printk("\n");
968 		dump_tlb_all();
969 	}
970 
971 	show_code((unsigned int __user *) regs->cp0_epc);
972 
973 	/*
974 	 * Some chips may have other causes of machine check (e.g. SB1
975 	 * graduation timer)
976 	 */
977 	panic("Caught Machine Check exception - %scaused by multiple "
978 	      "matching entries in the TLB.",
979 	      (multi_match) ? "" : "not ");
980 }
981 
982 asmlinkage void do_mt(struct pt_regs *regs)
983 {
984 	int subcode;
985 
986 	subcode = (read_vpe_c0_vpecontrol() & VPECONTROL_EXCPT)
987 			>> VPECONTROL_EXCPT_SHIFT;
988 	switch (subcode) {
989 	case 0:
990 		printk(KERN_DEBUG "Thread Underflow\n");
991 		break;
992 	case 1:
993 		printk(KERN_DEBUG "Thread Overflow\n");
994 		break;
995 	case 2:
996 		printk(KERN_DEBUG "Invalid YIELD Qualifier\n");
997 		break;
998 	case 3:
999 		printk(KERN_DEBUG "Gating Storage Exception\n");
1000 		break;
1001 	case 4:
1002 		printk(KERN_DEBUG "YIELD Scheduler Exception\n");
1003 		break;
1004 	case 5:
1005 		printk(KERN_DEBUG "Gating Storage Schedulier Exception\n");
1006 		break;
1007 	default:
1008 		printk(KERN_DEBUG "*** UNKNOWN THREAD EXCEPTION %d ***\n",
1009 			subcode);
1010 		break;
1011 	}
1012 	die_if_kernel("MIPS MT Thread exception in kernel", regs);
1013 
1014 	force_sig(SIGILL, current);
1015 }
1016 
1017 
1018 asmlinkage void do_dsp(struct pt_regs *regs)
1019 {
1020 	if (cpu_has_dsp)
1021 		panic("Unexpected DSP exception\n");
1022 
1023 	force_sig(SIGILL, current);
1024 }
1025 
1026 asmlinkage void do_reserved(struct pt_regs *regs)
1027 {
1028 	/*
1029 	 * Game over - no way to handle this if it ever occurs.  Most probably
1030 	 * caused by a new unknown cpu type or after another deadly
1031 	 * hard/software error.
1032 	 */
1033 	show_regs(regs);
1034 	panic("Caught reserved exception %ld - should not happen.",
1035 	      (regs->cp0_cause & 0x7f) >> 2);
1036 }
1037 
1038 static int __initdata l1parity = 1;
1039 static int __init nol1parity(char *s)
1040 {
1041 	l1parity = 0;
1042 	return 1;
1043 }
1044 __setup("nol1par", nol1parity);
1045 static int __initdata l2parity = 1;
1046 static int __init nol2parity(char *s)
1047 {
1048 	l2parity = 0;
1049 	return 1;
1050 }
1051 __setup("nol2par", nol2parity);
1052 
1053 /*
1054  * Some MIPS CPUs can enable/disable for cache parity detection, but do
1055  * it different ways.
1056  */
1057 static inline void parity_protection_init(void)
1058 {
1059 	switch (current_cpu_type()) {
1060 	case CPU_24K:
1061 	case CPU_34K:
1062 	case CPU_74K:
1063 	case CPU_1004K:
1064 		{
1065 #define ERRCTL_PE	0x80000000
1066 #define ERRCTL_L2P	0x00800000
1067 			unsigned long errctl;
1068 			unsigned int l1parity_present, l2parity_present;
1069 
1070 			errctl = read_c0_ecc();
1071 			errctl &= ~(ERRCTL_PE|ERRCTL_L2P);
1072 
1073 			/* probe L1 parity support */
1074 			write_c0_ecc(errctl | ERRCTL_PE);
1075 			back_to_back_c0_hazard();
1076 			l1parity_present = (read_c0_ecc() & ERRCTL_PE);
1077 
1078 			/* probe L2 parity support */
1079 			write_c0_ecc(errctl|ERRCTL_L2P);
1080 			back_to_back_c0_hazard();
1081 			l2parity_present = (read_c0_ecc() & ERRCTL_L2P);
1082 
1083 			if (l1parity_present && l2parity_present) {
1084 				if (l1parity)
1085 					errctl |= ERRCTL_PE;
1086 				if (l1parity ^ l2parity)
1087 					errctl |= ERRCTL_L2P;
1088 			} else if (l1parity_present) {
1089 				if (l1parity)
1090 					errctl |= ERRCTL_PE;
1091 			} else if (l2parity_present) {
1092 				if (l2parity)
1093 					errctl |= ERRCTL_L2P;
1094 			} else {
1095 				/* No parity available */
1096 			}
1097 
1098 			printk(KERN_INFO "Writing ErrCtl register=%08lx\n", errctl);
1099 
1100 			write_c0_ecc(errctl);
1101 			back_to_back_c0_hazard();
1102 			errctl = read_c0_ecc();
1103 			printk(KERN_INFO "Readback ErrCtl register=%08lx\n", errctl);
1104 
1105 			if (l1parity_present)
1106 				printk(KERN_INFO "Cache parity protection %sabled\n",
1107 				       (errctl & ERRCTL_PE) ? "en" : "dis");
1108 
1109 			if (l2parity_present) {
1110 				if (l1parity_present && l1parity)
1111 					errctl ^= ERRCTL_L2P;
1112 				printk(KERN_INFO "L2 cache parity protection %sabled\n",
1113 				       (errctl & ERRCTL_L2P) ? "en" : "dis");
1114 			}
1115 		}
1116 		break;
1117 
1118 	case CPU_5KC:
1119 		write_c0_ecc(0x80000000);
1120 		back_to_back_c0_hazard();
1121 		/* Set the PE bit (bit 31) in the c0_errctl register. */
1122 		printk(KERN_INFO "Cache parity protection %sabled\n",
1123 		       (read_c0_ecc() & 0x80000000) ? "en" : "dis");
1124 		break;
1125 	case CPU_20KC:
1126 	case CPU_25KF:
1127 		/* Clear the DE bit (bit 16) in the c0_status register. */
1128 		printk(KERN_INFO "Enable cache parity protection for "
1129 		       "MIPS 20KC/25KF CPUs.\n");
1130 		clear_c0_status(ST0_DE);
1131 		break;
1132 	default:
1133 		break;
1134 	}
1135 }
1136 
1137 asmlinkage void cache_parity_error(void)
1138 {
1139 	const int field = 2 * sizeof(unsigned long);
1140 	unsigned int reg_val;
1141 
1142 	/* For the moment, report the problem and hang. */
1143 	printk("Cache error exception:\n");
1144 	printk("cp0_errorepc == %0*lx\n", field, read_c0_errorepc());
1145 	reg_val = read_c0_cacheerr();
1146 	printk("c0_cacheerr == %08x\n", reg_val);
1147 
1148 	printk("Decoded c0_cacheerr: %s cache fault in %s reference.\n",
1149 	       reg_val & (1<<30) ? "secondary" : "primary",
1150 	       reg_val & (1<<31) ? "data" : "insn");
1151 	printk("Error bits: %s%s%s%s%s%s%s\n",
1152 	       reg_val & (1<<29) ? "ED " : "",
1153 	       reg_val & (1<<28) ? "ET " : "",
1154 	       reg_val & (1<<26) ? "EE " : "",
1155 	       reg_val & (1<<25) ? "EB " : "",
1156 	       reg_val & (1<<24) ? "EI " : "",
1157 	       reg_val & (1<<23) ? "E1 " : "",
1158 	       reg_val & (1<<22) ? "E0 " : "");
1159 	printk("IDX: 0x%08x\n", reg_val & ((1<<22)-1));
1160 
1161 #if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
1162 	if (reg_val & (1<<22))
1163 		printk("DErrAddr0: 0x%0*lx\n", field, read_c0_derraddr0());
1164 
1165 	if (reg_val & (1<<23))
1166 		printk("DErrAddr1: 0x%0*lx\n", field, read_c0_derraddr1());
1167 #endif
1168 
1169 	panic("Can't handle the cache error!");
1170 }
1171 
1172 /*
1173  * SDBBP EJTAG debug exception handler.
1174  * We skip the instruction and return to the next instruction.
1175  */
1176 void ejtag_exception_handler(struct pt_regs *regs)
1177 {
1178 	const int field = 2 * sizeof(unsigned long);
1179 	unsigned long depc, old_epc;
1180 	unsigned int debug;
1181 
1182 	printk(KERN_DEBUG "SDBBP EJTAG debug exception - not handled yet, just ignored!\n");
1183 	depc = read_c0_depc();
1184 	debug = read_c0_debug();
1185 	printk(KERN_DEBUG "c0_depc = %0*lx, DEBUG = %08x\n", field, depc, debug);
1186 	if (debug & 0x80000000) {
1187 		/*
1188 		 * In branch delay slot.
1189 		 * We cheat a little bit here and use EPC to calculate the
1190 		 * debug return address (DEPC). EPC is restored after the
1191 		 * calculation.
1192 		 */
1193 		old_epc = regs->cp0_epc;
1194 		regs->cp0_epc = depc;
1195 		__compute_return_epc(regs);
1196 		depc = regs->cp0_epc;
1197 		regs->cp0_epc = old_epc;
1198 	} else
1199 		depc += 4;
1200 	write_c0_depc(depc);
1201 
1202 #if 0
1203 	printk(KERN_DEBUG "\n\n----- Enable EJTAG single stepping ----\n\n");
1204 	write_c0_debug(debug | 0x100);
1205 #endif
1206 }
1207 
1208 /*
1209  * NMI exception handler.
1210  */
1211 NORET_TYPE void ATTRIB_NORET nmi_exception_handler(struct pt_regs *regs)
1212 {
1213 	bust_spinlocks(1);
1214 	printk("NMI taken!!!!\n");
1215 	die("NMI", regs);
1216 }
1217 
1218 #define VECTORSPACING 0x100	/* for EI/VI mode */
1219 
1220 unsigned long ebase;
1221 unsigned long exception_handlers[32];
1222 unsigned long vi_handlers[64];
1223 
1224 /*
1225  * As a side effect of the way this is implemented we're limited
1226  * to interrupt handlers in the address range from
1227  * KSEG0 <= x < KSEG0 + 256mb on the Nevada.  Oh well ...
1228  */
1229 void *set_except_vector(int n, void *addr)
1230 {
1231 	unsigned long handler = (unsigned long) addr;
1232 	unsigned long old_handler = exception_handlers[n];
1233 
1234 	exception_handlers[n] = handler;
1235 	if (n == 0 && cpu_has_divec) {
1236 		*(u32 *)(ebase + 0x200) = 0x08000000 |
1237 					  (0x03ffffff & (handler >> 2));
1238 		local_flush_icache_range(ebase + 0x200, ebase + 0x204);
1239 	}
1240 	return (void *)old_handler;
1241 }
1242 
1243 static asmlinkage void do_default_vi(void)
1244 {
1245 	show_regs(get_irq_regs());
1246 	panic("Caught unexpected vectored interrupt.");
1247 }
1248 
1249 static void *set_vi_srs_handler(int n, vi_handler_t addr, int srs)
1250 {
1251 	unsigned long handler;
1252 	unsigned long old_handler = vi_handlers[n];
1253 	int srssets = current_cpu_data.srsets;
1254 	u32 *w;
1255 	unsigned char *b;
1256 
1257 	if (!cpu_has_veic && !cpu_has_vint)
1258 		BUG();
1259 
1260 	if (addr == NULL) {
1261 		handler = (unsigned long) do_default_vi;
1262 		srs = 0;
1263 	} else
1264 		handler = (unsigned long) addr;
1265 	vi_handlers[n] = (unsigned long) addr;
1266 
1267 	b = (unsigned char *)(ebase + 0x200 + n*VECTORSPACING);
1268 
1269 	if (srs >= srssets)
1270 		panic("Shadow register set %d not supported", srs);
1271 
1272 	if (cpu_has_veic) {
1273 		if (board_bind_eic_interrupt)
1274 			board_bind_eic_interrupt(n, srs);
1275 	} else if (cpu_has_vint) {
1276 		/* SRSMap is only defined if shadow sets are implemented */
1277 		if (srssets > 1)
1278 			change_c0_srsmap(0xf << n*4, srs << n*4);
1279 	}
1280 
1281 	if (srs == 0) {
1282 		/*
1283 		 * If no shadow set is selected then use the default handler
1284 		 * that does normal register saving and a standard interrupt exit
1285 		 */
1286 
1287 		extern char except_vec_vi, except_vec_vi_lui;
1288 		extern char except_vec_vi_ori, except_vec_vi_end;
1289 		extern char rollback_except_vec_vi;
1290 		char *vec_start = (cpu_wait == r4k_wait) ?
1291 			&rollback_except_vec_vi : &except_vec_vi;
1292 #ifdef CONFIG_MIPS_MT_SMTC
1293 		/*
1294 		 * We need to provide the SMTC vectored interrupt handler
1295 		 * not only with the address of the handler, but with the
1296 		 * Status.IM bit to be masked before going there.
1297 		 */
1298 		extern char except_vec_vi_mori;
1299 		const int mori_offset = &except_vec_vi_mori - vec_start;
1300 #endif /* CONFIG_MIPS_MT_SMTC */
1301 		const int handler_len = &except_vec_vi_end - vec_start;
1302 		const int lui_offset = &except_vec_vi_lui - vec_start;
1303 		const int ori_offset = &except_vec_vi_ori - vec_start;
1304 
1305 		if (handler_len > VECTORSPACING) {
1306 			/*
1307 			 * Sigh... panicing won't help as the console
1308 			 * is probably not configured :(
1309 			 */
1310 			panic("VECTORSPACING too small");
1311 		}
1312 
1313 		memcpy(b, vec_start, handler_len);
1314 #ifdef CONFIG_MIPS_MT_SMTC
1315 		BUG_ON(n > 7);	/* Vector index %d exceeds SMTC maximum. */
1316 
1317 		w = (u32 *)(b + mori_offset);
1318 		*w = (*w & 0xffff0000) | (0x100 << n);
1319 #endif /* CONFIG_MIPS_MT_SMTC */
1320 		w = (u32 *)(b + lui_offset);
1321 		*w = (*w & 0xffff0000) | (((u32)handler >> 16) & 0xffff);
1322 		w = (u32 *)(b + ori_offset);
1323 		*w = (*w & 0xffff0000) | ((u32)handler & 0xffff);
1324 		local_flush_icache_range((unsigned long)b,
1325 					 (unsigned long)(b+handler_len));
1326 	}
1327 	else {
1328 		/*
1329 		 * In other cases jump directly to the interrupt handler
1330 		 *
1331 		 * It is the handlers responsibility to save registers if required
1332 		 * (eg hi/lo) and return from the exception using "eret"
1333 		 */
1334 		w = (u32 *)b;
1335 		*w++ = 0x08000000 | (((u32)handler >> 2) & 0x03fffff); /* j handler */
1336 		*w = 0;
1337 		local_flush_icache_range((unsigned long)b,
1338 					 (unsigned long)(b+8));
1339 	}
1340 
1341 	return (void *)old_handler;
1342 }
1343 
1344 void *set_vi_handler(int n, vi_handler_t addr)
1345 {
1346 	return set_vi_srs_handler(n, addr, 0);
1347 }
1348 
1349 /*
1350  * This is used by native signal handling
1351  */
1352 asmlinkage int (*save_fp_context)(struct sigcontext __user *sc);
1353 asmlinkage int (*restore_fp_context)(struct sigcontext __user *sc);
1354 
1355 extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
1356 extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
1357 
1358 extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc);
1359 extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc);
1360 
1361 #ifdef CONFIG_SMP
1362 static int smp_save_fp_context(struct sigcontext __user *sc)
1363 {
1364 	return raw_cpu_has_fpu
1365 	       ? _save_fp_context(sc)
1366 	       : fpu_emulator_save_context(sc);
1367 }
1368 
1369 static int smp_restore_fp_context(struct sigcontext __user *sc)
1370 {
1371 	return raw_cpu_has_fpu
1372 	       ? _restore_fp_context(sc)
1373 	       : fpu_emulator_restore_context(sc);
1374 }
1375 #endif
1376 
1377 static inline void signal_init(void)
1378 {
1379 #ifdef CONFIG_SMP
1380 	/* For now just do the cpu_has_fpu check when the functions are invoked */
1381 	save_fp_context = smp_save_fp_context;
1382 	restore_fp_context = smp_restore_fp_context;
1383 #else
1384 	if (cpu_has_fpu) {
1385 		save_fp_context = _save_fp_context;
1386 		restore_fp_context = _restore_fp_context;
1387 	} else {
1388 		save_fp_context = fpu_emulator_save_context;
1389 		restore_fp_context = fpu_emulator_restore_context;
1390 	}
1391 #endif
1392 }
1393 
1394 #ifdef CONFIG_MIPS32_COMPAT
1395 
1396 /*
1397  * This is used by 32-bit signal stuff on the 64-bit kernel
1398  */
1399 asmlinkage int (*save_fp_context32)(struct sigcontext32 __user *sc);
1400 asmlinkage int (*restore_fp_context32)(struct sigcontext32 __user *sc);
1401 
1402 extern asmlinkage int _save_fp_context32(struct sigcontext32 __user *sc);
1403 extern asmlinkage int _restore_fp_context32(struct sigcontext32 __user *sc);
1404 
1405 extern asmlinkage int fpu_emulator_save_context32(struct sigcontext32 __user *sc);
1406 extern asmlinkage int fpu_emulator_restore_context32(struct sigcontext32 __user *sc);
1407 
1408 static inline void signal32_init(void)
1409 {
1410 	if (cpu_has_fpu) {
1411 		save_fp_context32 = _save_fp_context32;
1412 		restore_fp_context32 = _restore_fp_context32;
1413 	} else {
1414 		save_fp_context32 = fpu_emulator_save_context32;
1415 		restore_fp_context32 = fpu_emulator_restore_context32;
1416 	}
1417 }
1418 #endif
1419 
1420 extern void cpu_cache_init(void);
1421 extern void tlb_init(void);
1422 extern void flush_tlb_handlers(void);
1423 
1424 /*
1425  * Timer interrupt
1426  */
1427 int cp0_compare_irq;
1428 
1429 /*
1430  * Performance counter IRQ or -1 if shared with timer
1431  */
1432 int cp0_perfcount_irq;
1433 EXPORT_SYMBOL_GPL(cp0_perfcount_irq);
1434 
1435 static int __cpuinitdata noulri;
1436 
1437 static int __init ulri_disable(char *s)
1438 {
1439 	pr_info("Disabling ulri\n");
1440 	noulri = 1;
1441 
1442 	return 1;
1443 }
1444 __setup("noulri", ulri_disable);
1445 
1446 void __cpuinit per_cpu_trap_init(void)
1447 {
1448 	unsigned int cpu = smp_processor_id();
1449 	unsigned int status_set = ST0_CU0;
1450 #ifdef CONFIG_MIPS_MT_SMTC
1451 	int secondaryTC = 0;
1452 	int bootTC = (cpu == 0);
1453 
1454 	/*
1455 	 * Only do per_cpu_trap_init() for first TC of Each VPE.
1456 	 * Note that this hack assumes that the SMTC init code
1457 	 * assigns TCs consecutively and in ascending order.
1458 	 */
1459 
1460 	if (((read_c0_tcbind() & TCBIND_CURTC) != 0) &&
1461 	    ((read_c0_tcbind() & TCBIND_CURVPE) == cpu_data[cpu - 1].vpe_id))
1462 		secondaryTC = 1;
1463 #endif /* CONFIG_MIPS_MT_SMTC */
1464 
1465 	/*
1466 	 * Disable coprocessors and select 32-bit or 64-bit addressing
1467 	 * and the 16/32 or 32/32 FPR register model.  Reset the BEV
1468 	 * flag that some firmware may have left set and the TS bit (for
1469 	 * IP27).  Set XX for ISA IV code to work.
1470 	 */
1471 #ifdef CONFIG_64BIT
1472 	status_set |= ST0_FR|ST0_KX|ST0_SX|ST0_UX;
1473 #endif
1474 	if (current_cpu_data.isa_level == MIPS_CPU_ISA_IV)
1475 		status_set |= ST0_XX;
1476 	if (cpu_has_dsp)
1477 		status_set |= ST0_MX;
1478 
1479 	change_c0_status(ST0_CU|ST0_MX|ST0_RE|ST0_FR|ST0_BEV|ST0_TS|ST0_KX|ST0_SX|ST0_UX,
1480 			 status_set);
1481 
1482 	if (cpu_has_mips_r2) {
1483 		unsigned int enable = 0x0000000f;
1484 
1485 		if (!noulri && cpu_has_userlocal)
1486 			enable |= (1 << 29);
1487 
1488 		write_c0_hwrena(enable);
1489 	}
1490 
1491 #ifdef CONFIG_MIPS_MT_SMTC
1492 	if (!secondaryTC) {
1493 #endif /* CONFIG_MIPS_MT_SMTC */
1494 
1495 	if (cpu_has_veic || cpu_has_vint) {
1496 		write_c0_ebase(ebase);
1497 		/* Setting vector spacing enables EI/VI mode  */
1498 		change_c0_intctl(0x3e0, VECTORSPACING);
1499 	}
1500 	if (cpu_has_divec) {
1501 		if (cpu_has_mipsmt) {
1502 			unsigned int vpflags = dvpe();
1503 			set_c0_cause(CAUSEF_IV);
1504 			evpe(vpflags);
1505 		} else
1506 			set_c0_cause(CAUSEF_IV);
1507 	}
1508 
1509 	/*
1510 	 * Before R2 both interrupt numbers were fixed to 7, so on R2 only:
1511 	 *
1512 	 *  o read IntCtl.IPTI to determine the timer interrupt
1513 	 *  o read IntCtl.IPPCI to determine the performance counter interrupt
1514 	 */
1515 	if (cpu_has_mips_r2) {
1516 		cp0_compare_irq = (read_c0_intctl() >> 29) & 7;
1517 		cp0_perfcount_irq = (read_c0_intctl() >> 26) & 7;
1518 		if (cp0_perfcount_irq == cp0_compare_irq)
1519 			cp0_perfcount_irq = -1;
1520 	} else {
1521 		cp0_compare_irq = CP0_LEGACY_COMPARE_IRQ;
1522 		cp0_perfcount_irq = -1;
1523 	}
1524 
1525 #ifdef CONFIG_MIPS_MT_SMTC
1526 	}
1527 #endif /* CONFIG_MIPS_MT_SMTC */
1528 
1529 	cpu_data[cpu].asid_cache = ASID_FIRST_VERSION;
1530 	TLBMISS_HANDLER_SETUP();
1531 
1532 	atomic_inc(&init_mm.mm_count);
1533 	current->active_mm = &init_mm;
1534 	BUG_ON(current->mm);
1535 	enter_lazy_tlb(&init_mm, current);
1536 
1537 #ifdef CONFIG_MIPS_MT_SMTC
1538 	if (bootTC) {
1539 #endif /* CONFIG_MIPS_MT_SMTC */
1540 		cpu_cache_init();
1541 		tlb_init();
1542 #ifdef CONFIG_MIPS_MT_SMTC
1543 	} else if (!secondaryTC) {
1544 		/*
1545 		 * First TC in non-boot VPE must do subset of tlb_init()
1546 		 * for MMU countrol registers.
1547 		 */
1548 		write_c0_pagemask(PM_DEFAULT_MASK);
1549 		write_c0_wired(0);
1550 	}
1551 #endif /* CONFIG_MIPS_MT_SMTC */
1552 }
1553 
1554 /* Install CPU exception handler */
1555 void __init set_handler(unsigned long offset, void *addr, unsigned long size)
1556 {
1557 	memcpy((void *)(ebase + offset), addr, size);
1558 	local_flush_icache_range(ebase + offset, ebase + offset + size);
1559 }
1560 
1561 static char panic_null_cerr[] __cpuinitdata =
1562 	"Trying to set NULL cache error exception handler";
1563 
1564 /* Install uncached CPU exception handler */
1565 void __cpuinit set_uncached_handler(unsigned long offset, void *addr,
1566 	unsigned long size)
1567 {
1568 #ifdef CONFIG_32BIT
1569 	unsigned long uncached_ebase = KSEG1ADDR(ebase);
1570 #endif
1571 #ifdef CONFIG_64BIT
1572 	unsigned long uncached_ebase = TO_UNCAC(ebase);
1573 #endif
1574 	if (cpu_has_mips_r2)
1575 		ebase += (read_c0_ebase() & 0x3ffff000);
1576 
1577 	if (!addr)
1578 		panic(panic_null_cerr);
1579 
1580 	memcpy((void *)(uncached_ebase + offset), addr, size);
1581 }
1582 
1583 static int __initdata rdhwr_noopt;
1584 static int __init set_rdhwr_noopt(char *str)
1585 {
1586 	rdhwr_noopt = 1;
1587 	return 1;
1588 }
1589 
1590 __setup("rdhwr_noopt", set_rdhwr_noopt);
1591 
1592 void __init trap_init(void)
1593 {
1594 	extern char except_vec3_generic, except_vec3_r4000;
1595 	extern char except_vec4;
1596 	unsigned long i;
1597 	int rollback;
1598 
1599 	check_wait();
1600 	rollback = (cpu_wait == r4k_wait);
1601 
1602 #if defined(CONFIG_KGDB)
1603 	if (kgdb_early_setup)
1604 		return;	/* Already done */
1605 #endif
1606 
1607 	if (cpu_has_veic || cpu_has_vint)
1608 		ebase = (unsigned long) alloc_bootmem_low_pages(0x200 + VECTORSPACING*64);
1609 	else {
1610 		ebase = CAC_BASE;
1611 		if (cpu_has_mips_r2)
1612 			ebase += (read_c0_ebase() & 0x3ffff000);
1613 	}
1614 
1615 	per_cpu_trap_init();
1616 
1617 	/*
1618 	 * Copy the generic exception handlers to their final destination.
1619 	 * This will be overriden later as suitable for a particular
1620 	 * configuration.
1621 	 */
1622 	set_handler(0x180, &except_vec3_generic, 0x80);
1623 
1624 	/*
1625 	 * Setup default vectors
1626 	 */
1627 	for (i = 0; i <= 31; i++)
1628 		set_except_vector(i, handle_reserved);
1629 
1630 	/*
1631 	 * Copy the EJTAG debug exception vector handler code to it's final
1632 	 * destination.
1633 	 */
1634 	if (cpu_has_ejtag && board_ejtag_handler_setup)
1635 		board_ejtag_handler_setup();
1636 
1637 	/*
1638 	 * Only some CPUs have the watch exceptions.
1639 	 */
1640 	if (cpu_has_watch)
1641 		set_except_vector(23, handle_watch);
1642 
1643 	/*
1644 	 * Initialise interrupt handlers
1645 	 */
1646 	if (cpu_has_veic || cpu_has_vint) {
1647 		int nvec = cpu_has_veic ? 64 : 8;
1648 		for (i = 0; i < nvec; i++)
1649 			set_vi_handler(i, NULL);
1650 	}
1651 	else if (cpu_has_divec)
1652 		set_handler(0x200, &except_vec4, 0x8);
1653 
1654 	/*
1655 	 * Some CPUs can enable/disable for cache parity detection, but does
1656 	 * it different ways.
1657 	 */
1658 	parity_protection_init();
1659 
1660 	/*
1661 	 * The Data Bus Errors / Instruction Bus Errors are signaled
1662 	 * by external hardware.  Therefore these two exceptions
1663 	 * may have board specific handlers.
1664 	 */
1665 	if (board_be_init)
1666 		board_be_init();
1667 
1668 	set_except_vector(0, rollback ? rollback_handle_int : handle_int);
1669 	set_except_vector(1, handle_tlbm);
1670 	set_except_vector(2, handle_tlbl);
1671 	set_except_vector(3, handle_tlbs);
1672 
1673 	set_except_vector(4, handle_adel);
1674 	set_except_vector(5, handle_ades);
1675 
1676 	set_except_vector(6, handle_ibe);
1677 	set_except_vector(7, handle_dbe);
1678 
1679 	set_except_vector(8, handle_sys);
1680 	set_except_vector(9, handle_bp);
1681 	set_except_vector(10, rdhwr_noopt ? handle_ri :
1682 			  (cpu_has_vtag_icache ?
1683 			   handle_ri_rdhwr_vivt : handle_ri_rdhwr));
1684 	set_except_vector(11, handle_cpu);
1685 	set_except_vector(12, handle_ov);
1686 	set_except_vector(13, handle_tr);
1687 
1688 	if (current_cpu_type() == CPU_R6000 ||
1689 	    current_cpu_type() == CPU_R6000A) {
1690 		/*
1691 		 * The R6000 is the only R-series CPU that features a machine
1692 		 * check exception (similar to the R4000 cache error) and
1693 		 * unaligned ldc1/sdc1 exception.  The handlers have not been
1694 		 * written yet.  Well, anyway there is no R6000 machine on the
1695 		 * current list of targets for Linux/MIPS.
1696 		 * (Duh, crap, there is someone with a triple R6k machine)
1697 		 */
1698 		//set_except_vector(14, handle_mc);
1699 		//set_except_vector(15, handle_ndc);
1700 	}
1701 
1702 
1703 	if (board_nmi_handler_setup)
1704 		board_nmi_handler_setup();
1705 
1706 	if (cpu_has_fpu && !cpu_has_nofpuex)
1707 		set_except_vector(15, handle_fpe);
1708 
1709 	set_except_vector(22, handle_mdmx);
1710 
1711 	if (cpu_has_mcheck)
1712 		set_except_vector(24, handle_mcheck);
1713 
1714 	if (cpu_has_mipsmt)
1715 		set_except_vector(25, handle_mt);
1716 
1717 	set_except_vector(26, handle_dsp);
1718 
1719 	if (cpu_has_vce)
1720 		/* Special exception: R4[04]00 uses also the divec space. */
1721 		memcpy((void *)(ebase + 0x180), &except_vec3_r4000, 0x100);
1722 	else if (cpu_has_4kex)
1723 		memcpy((void *)(ebase + 0x180), &except_vec3_generic, 0x80);
1724 	else
1725 		memcpy((void *)(ebase + 0x080), &except_vec3_generic, 0x80);
1726 
1727 	signal_init();
1728 #ifdef CONFIG_MIPS32_COMPAT
1729 	signal32_init();
1730 #endif
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