xref: /linux/arch/mips/kernel/traps.c (revision a5766f11cfd3a0c03450d99c8fe548c2940be884)
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/mipsregs.h>
36 #include <asm/mipsmtregs.h>
37 #include <asm/module.h>
38 #include <asm/pgtable.h>
39 #include <asm/ptrace.h>
40 #include <asm/sections.h>
41 #include <asm/system.h>
42 #include <asm/tlbdebug.h>
43 #include <asm/traps.h>
44 #include <asm/uaccess.h>
45 #include <asm/watch.h>
46 #include <asm/mmu_context.h>
47 #include <asm/types.h>
48 #include <asm/stacktrace.h>
49 
50 extern void check_wait(void);
51 extern asmlinkage void r4k_wait(void);
52 extern asmlinkage void rollback_handle_int(void);
53 extern asmlinkage void handle_int(void);
54 extern asmlinkage void handle_tlbm(void);
55 extern asmlinkage void handle_tlbl(void);
56 extern asmlinkage void handle_tlbs(void);
57 extern asmlinkage void handle_adel(void);
58 extern asmlinkage void handle_ades(void);
59 extern asmlinkage void handle_ibe(void);
60 extern asmlinkage void handle_dbe(void);
61 extern asmlinkage void handle_sys(void);
62 extern asmlinkage void handle_bp(void);
63 extern asmlinkage void handle_ri(void);
64 extern asmlinkage void handle_ri_rdhwr_vivt(void);
65 extern asmlinkage void handle_ri_rdhwr(void);
66 extern asmlinkage void handle_cpu(void);
67 extern asmlinkage void handle_ov(void);
68 extern asmlinkage void handle_tr(void);
69 extern asmlinkage void handle_fpe(void);
70 extern asmlinkage void handle_mdmx(void);
71 extern asmlinkage void handle_watch(void);
72 extern asmlinkage void handle_mt(void);
73 extern asmlinkage void handle_dsp(void);
74 extern asmlinkage void handle_mcheck(void);
75 extern asmlinkage void handle_reserved(void);
76 
77 extern int fpu_emulator_cop1Handler(struct pt_regs *xcp,
78 	struct mips_fpu_struct *ctx, int has_fpu);
79 
80 void (*board_be_init)(void);
81 int (*board_be_handler)(struct pt_regs *regs, int is_fixup);
82 void (*board_nmi_handler_setup)(void);
83 void (*board_ejtag_handler_setup)(void);
84 void (*board_bind_eic_interrupt)(int irq, int regset);
85 
86 
87 static void show_raw_backtrace(unsigned long reg29)
88 {
89 	unsigned long *sp = (unsigned long *)(reg29 & ~3);
90 	unsigned long addr;
91 
92 	printk("Call Trace:");
93 #ifdef CONFIG_KALLSYMS
94 	printk("\n");
95 #endif
96 	while (!kstack_end(sp)) {
97 		unsigned long __user *p =
98 			(unsigned long __user *)(unsigned long)sp++;
99 		if (__get_user(addr, p)) {
100 			printk(" (Bad stack address)");
101 			break;
102 		}
103 		if (__kernel_text_address(addr))
104 			print_ip_sym(addr);
105 	}
106 	printk("\n");
107 }
108 
109 #ifdef CONFIG_KALLSYMS
110 int raw_show_trace;
111 static int __init set_raw_show_trace(char *str)
112 {
113 	raw_show_trace = 1;
114 	return 1;
115 }
116 __setup("raw_show_trace", set_raw_show_trace);
117 #endif
118 
119 static void show_backtrace(struct task_struct *task, const struct pt_regs *regs)
120 {
121 	unsigned long sp = regs->regs[29];
122 	unsigned long ra = regs->regs[31];
123 	unsigned long pc = regs->cp0_epc;
124 
125 	if (raw_show_trace || !__kernel_text_address(pc)) {
126 		show_raw_backtrace(sp);
127 		return;
128 	}
129 	printk("Call Trace:\n");
130 	do {
131 		print_ip_sym(pc);
132 		pc = unwind_stack(task, &sp, pc, &ra);
133 	} while (pc);
134 	printk("\n");
135 }
136 
137 /*
138  * This routine abuses get_user()/put_user() to reference pointers
139  * with at least a bit of error checking ...
140  */
141 static void show_stacktrace(struct task_struct *task,
142 	const struct pt_regs *regs)
143 {
144 	const int field = 2 * sizeof(unsigned long);
145 	long stackdata;
146 	int i;
147 	unsigned long __user *sp = (unsigned long __user *)regs->regs[29];
148 
149 	printk("Stack :");
150 	i = 0;
151 	while ((unsigned long) sp & (PAGE_SIZE - 1)) {
152 		if (i && ((i % (64 / field)) == 0))
153 			printk("\n       ");
154 		if (i > 39) {
155 			printk(" ...");
156 			break;
157 		}
158 
159 		if (__get_user(stackdata, sp++)) {
160 			printk(" (Bad stack address)");
161 			break;
162 		}
163 
164 		printk(" %0*lx", field, stackdata);
165 		i++;
166 	}
167 	printk("\n");
168 	show_backtrace(task, regs);
169 }
170 
171 void show_stack(struct task_struct *task, unsigned long *sp)
172 {
173 	struct pt_regs regs;
174 	if (sp) {
175 		regs.regs[29] = (unsigned long)sp;
176 		regs.regs[31] = 0;
177 		regs.cp0_epc = 0;
178 	} else {
179 		if (task && task != current) {
180 			regs.regs[29] = task->thread.reg29;
181 			regs.regs[31] = 0;
182 			regs.cp0_epc = task->thread.reg31;
183 		} else {
184 			prepare_frametrace(&regs);
185 		}
186 	}
187 	show_stacktrace(task, &regs);
188 }
189 
190 /*
191  * The architecture-independent dump_stack generator
192  */
193 void dump_stack(void)
194 {
195 	struct pt_regs regs;
196 
197 	prepare_frametrace(&regs);
198 	show_backtrace(current, &regs);
199 }
200 
201 EXPORT_SYMBOL(dump_stack);
202 
203 static void show_code(unsigned int __user *pc)
204 {
205 	long i;
206 	unsigned short __user *pc16 = NULL;
207 
208 	printk("\nCode:");
209 
210 	if ((unsigned long)pc & 1)
211 		pc16 = (unsigned short __user *)((unsigned long)pc & ~1);
212 	for(i = -3 ; i < 6 ; i++) {
213 		unsigned int insn;
214 		if (pc16 ? __get_user(insn, pc16 + i) : __get_user(insn, pc + i)) {
215 			printk(" (Bad address in epc)\n");
216 			break;
217 		}
218 		printk("%c%0*x%c", (i?' ':'<'), pc16 ? 4 : 8, insn, (i?' ':'>'));
219 	}
220 }
221 
222 static void __show_regs(const struct pt_regs *regs)
223 {
224 	const int field = 2 * sizeof(unsigned long);
225 	unsigned int cause = regs->cp0_cause;
226 	int i;
227 
228 	printk("Cpu %d\n", smp_processor_id());
229 
230 	/*
231 	 * Saved main processor registers
232 	 */
233 	for (i = 0; i < 32; ) {
234 		if ((i % 4) == 0)
235 			printk("$%2d   :", i);
236 		if (i == 0)
237 			printk(" %0*lx", field, 0UL);
238 		else if (i == 26 || i == 27)
239 			printk(" %*s", field, "");
240 		else
241 			printk(" %0*lx", field, regs->regs[i]);
242 
243 		i++;
244 		if ((i % 4) == 0)
245 			printk("\n");
246 	}
247 
248 #ifdef CONFIG_CPU_HAS_SMARTMIPS
249 	printk("Acx    : %0*lx\n", field, regs->acx);
250 #endif
251 	printk("Hi    : %0*lx\n", field, regs->hi);
252 	printk("Lo    : %0*lx\n", field, regs->lo);
253 
254 	/*
255 	 * Saved cp0 registers
256 	 */
257 	printk("epc   : %0*lx %pS\n", field, regs->cp0_epc,
258 	       (void *) regs->cp0_epc);
259 	printk("    %s\n", print_tainted());
260 	printk("ra    : %0*lx %pS\n", field, regs->regs[31],
261 	       (void *) regs->regs[31]);
262 
263 	printk("Status: %08x    ", (uint32_t) regs->cp0_status);
264 
265 	if (current_cpu_data.isa_level == MIPS_CPU_ISA_I) {
266 		if (regs->cp0_status & ST0_KUO)
267 			printk("KUo ");
268 		if (regs->cp0_status & ST0_IEO)
269 			printk("IEo ");
270 		if (regs->cp0_status & ST0_KUP)
271 			printk("KUp ");
272 		if (regs->cp0_status & ST0_IEP)
273 			printk("IEp ");
274 		if (regs->cp0_status & ST0_KUC)
275 			printk("KUc ");
276 		if (regs->cp0_status & ST0_IEC)
277 			printk("IEc ");
278 	} else {
279 		if (regs->cp0_status & ST0_KX)
280 			printk("KX ");
281 		if (regs->cp0_status & ST0_SX)
282 			printk("SX ");
283 		if (regs->cp0_status & ST0_UX)
284 			printk("UX ");
285 		switch (regs->cp0_status & ST0_KSU) {
286 		case KSU_USER:
287 			printk("USER ");
288 			break;
289 		case KSU_SUPERVISOR:
290 			printk("SUPERVISOR ");
291 			break;
292 		case KSU_KERNEL:
293 			printk("KERNEL ");
294 			break;
295 		default:
296 			printk("BAD_MODE ");
297 			break;
298 		}
299 		if (regs->cp0_status & ST0_ERL)
300 			printk("ERL ");
301 		if (regs->cp0_status & ST0_EXL)
302 			printk("EXL ");
303 		if (regs->cp0_status & ST0_IE)
304 			printk("IE ");
305 	}
306 	printk("\n");
307 
308 	printk("Cause : %08x\n", cause);
309 
310 	cause = (cause & CAUSEF_EXCCODE) >> CAUSEB_EXCCODE;
311 	if (1 <= cause && cause <= 5)
312 		printk("BadVA : %0*lx\n", field, regs->cp0_badvaddr);
313 
314 	printk("PrId  : %08x (%s)\n", read_c0_prid(),
315 	       cpu_name_string());
316 }
317 
318 /*
319  * FIXME: really the generic show_regs should take a const pointer argument.
320  */
321 void show_regs(struct pt_regs *regs)
322 {
323 	__show_regs((struct pt_regs *)regs);
324 }
325 
326 void show_registers(const struct pt_regs *regs)
327 {
328 	const int field = 2 * sizeof(unsigned long);
329 
330 	__show_regs(regs);
331 	print_modules();
332 	printk("Process %s (pid: %d, threadinfo=%p, task=%p, tls=%0*lx)\n",
333 	       current->comm, current->pid, current_thread_info(), current,
334 	      field, current_thread_info()->tp_value);
335 	if (cpu_has_userlocal) {
336 		unsigned long tls;
337 
338 		tls = read_c0_userlocal();
339 		if (tls != current_thread_info()->tp_value)
340 			printk("*HwTLS: %0*lx\n", field, tls);
341 	}
342 
343 	show_stacktrace(current, regs);
344 	show_code((unsigned int __user *) regs->cp0_epc);
345 	printk("\n");
346 }
347 
348 static DEFINE_SPINLOCK(die_lock);
349 
350 void __noreturn die(const char * str, const struct pt_regs * regs)
351 {
352 	static int die_counter;
353 #ifdef CONFIG_MIPS_MT_SMTC
354 	unsigned long dvpret = dvpe();
355 #endif /* CONFIG_MIPS_MT_SMTC */
356 
357 	console_verbose();
358 	spin_lock_irq(&die_lock);
359 	bust_spinlocks(1);
360 #ifdef CONFIG_MIPS_MT_SMTC
361 	mips_mt_regdump(dvpret);
362 #endif /* CONFIG_MIPS_MT_SMTC */
363 	printk("%s[#%d]:\n", str, ++die_counter);
364 	show_registers(regs);
365 	add_taint(TAINT_DIE);
366 	spin_unlock_irq(&die_lock);
367 
368 	if (in_interrupt())
369 		panic("Fatal exception in interrupt");
370 
371 	if (panic_on_oops) {
372 		printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
373 		ssleep(5);
374 		panic("Fatal exception");
375 	}
376 
377 	do_exit(SIGSEGV);
378 }
379 
380 extern struct exception_table_entry __start___dbe_table[];
381 extern struct exception_table_entry __stop___dbe_table[];
382 
383 __asm__(
384 "	.section	__dbe_table, \"a\"\n"
385 "	.previous			\n");
386 
387 /* Given an address, look for it in the exception tables. */
388 static const struct exception_table_entry *search_dbe_tables(unsigned long addr)
389 {
390 	const struct exception_table_entry *e;
391 
392 	e = search_extable(__start___dbe_table, __stop___dbe_table - 1, addr);
393 	if (!e)
394 		e = search_module_dbetables(addr);
395 	return e;
396 }
397 
398 asmlinkage void do_be(struct pt_regs *regs)
399 {
400 	const int field = 2 * sizeof(unsigned long);
401 	const struct exception_table_entry *fixup = NULL;
402 	int data = regs->cp0_cause & 4;
403 	int action = MIPS_BE_FATAL;
404 
405 	/* XXX For now.  Fixme, this searches the wrong table ...  */
406 	if (data && !user_mode(regs))
407 		fixup = search_dbe_tables(exception_epc(regs));
408 
409 	if (fixup)
410 		action = MIPS_BE_FIXUP;
411 
412 	if (board_be_handler)
413 		action = board_be_handler(regs, fixup != NULL);
414 
415 	switch (action) {
416 	case MIPS_BE_DISCARD:
417 		return;
418 	case MIPS_BE_FIXUP:
419 		if (fixup) {
420 			regs->cp0_epc = fixup->nextinsn;
421 			return;
422 		}
423 		break;
424 	default:
425 		break;
426 	}
427 
428 	/*
429 	 * Assume it would be too dangerous to continue ...
430 	 */
431 	printk(KERN_ALERT "%s bus error, epc == %0*lx, ra == %0*lx\n",
432 	       data ? "Data" : "Instruction",
433 	       field, regs->cp0_epc, field, regs->regs[31]);
434 	if (notify_die(DIE_OOPS, "bus error", regs, SIGBUS, 0, 0)
435 	    == NOTIFY_STOP)
436 		return;
437 
438 	die_if_kernel("Oops", regs);
439 	force_sig(SIGBUS, current);
440 }
441 
442 /*
443  * ll/sc, rdhwr, sync emulation
444  */
445 
446 #define OPCODE 0xfc000000
447 #define BASE   0x03e00000
448 #define RT     0x001f0000
449 #define OFFSET 0x0000ffff
450 #define LL     0xc0000000
451 #define SC     0xe0000000
452 #define SPEC0  0x00000000
453 #define SPEC3  0x7c000000
454 #define RD     0x0000f800
455 #define FUNC   0x0000003f
456 #define SYNC   0x0000000f
457 #define RDHWR  0x0000003b
458 
459 /*
460  * The ll_bit is cleared by r*_switch.S
461  */
462 
463 unsigned long ll_bit;
464 
465 static struct task_struct *ll_task = NULL;
466 
467 static inline int simulate_ll(struct pt_regs *regs, unsigned int opcode)
468 {
469 	unsigned long value, __user *vaddr;
470 	long offset;
471 
472 	/*
473 	 * analyse the ll instruction that just caused a ri exception
474 	 * and put the referenced address to addr.
475 	 */
476 
477 	/* sign extend offset */
478 	offset = opcode & OFFSET;
479 	offset <<= 16;
480 	offset >>= 16;
481 
482 	vaddr = (unsigned long __user *)
483 	        ((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
484 
485 	if ((unsigned long)vaddr & 3)
486 		return SIGBUS;
487 	if (get_user(value, vaddr))
488 		return SIGSEGV;
489 
490 	preempt_disable();
491 
492 	if (ll_task == NULL || ll_task == current) {
493 		ll_bit = 1;
494 	} else {
495 		ll_bit = 0;
496 	}
497 	ll_task = current;
498 
499 	preempt_enable();
500 
501 	regs->regs[(opcode & RT) >> 16] = value;
502 
503 	return 0;
504 }
505 
506 static inline int simulate_sc(struct pt_regs *regs, unsigned int opcode)
507 {
508 	unsigned long __user *vaddr;
509 	unsigned long reg;
510 	long offset;
511 
512 	/*
513 	 * analyse the sc instruction that just caused a ri exception
514 	 * and put the referenced address to addr.
515 	 */
516 
517 	/* sign extend offset */
518 	offset = opcode & OFFSET;
519 	offset <<= 16;
520 	offset >>= 16;
521 
522 	vaddr = (unsigned long __user *)
523 	        ((unsigned long)(regs->regs[(opcode & BASE) >> 21]) + offset);
524 	reg = (opcode & RT) >> 16;
525 
526 	if ((unsigned long)vaddr & 3)
527 		return SIGBUS;
528 
529 	preempt_disable();
530 
531 	if (ll_bit == 0 || ll_task != current) {
532 		regs->regs[reg] = 0;
533 		preempt_enable();
534 		return 0;
535 	}
536 
537 	preempt_enable();
538 
539 	if (put_user(regs->regs[reg], vaddr))
540 		return SIGSEGV;
541 
542 	regs->regs[reg] = 1;
543 
544 	return 0;
545 }
546 
547 /*
548  * ll uses the opcode of lwc0 and sc uses the opcode of swc0.  That is both
549  * opcodes are supposed to result in coprocessor unusable exceptions if
550  * executed on ll/sc-less processors.  That's the theory.  In practice a
551  * few processors such as NEC's VR4100 throw reserved instruction exceptions
552  * instead, so we're doing the emulation thing in both exception handlers.
553  */
554 static int simulate_llsc(struct pt_regs *regs, unsigned int opcode)
555 {
556 	if ((opcode & OPCODE) == LL)
557 		return simulate_ll(regs, opcode);
558 	if ((opcode & OPCODE) == SC)
559 		return simulate_sc(regs, opcode);
560 
561 	return -1;			/* Must be something else ... */
562 }
563 
564 /*
565  * Simulate trapping 'rdhwr' instructions to provide user accessible
566  * registers not implemented in hardware.
567  */
568 static int simulate_rdhwr(struct pt_regs *regs, unsigned int opcode)
569 {
570 	struct thread_info *ti = task_thread_info(current);
571 
572 	if ((opcode & OPCODE) == SPEC3 && (opcode & FUNC) == RDHWR) {
573 		int rd = (opcode & RD) >> 11;
574 		int rt = (opcode & RT) >> 16;
575 		switch (rd) {
576 		case 0:		/* CPU number */
577 			regs->regs[rt] = smp_processor_id();
578 			return 0;
579 		case 1:		/* SYNCI length */
580 			regs->regs[rt] = min(current_cpu_data.dcache.linesz,
581 					     current_cpu_data.icache.linesz);
582 			return 0;
583 		case 2:		/* Read count register */
584 			regs->regs[rt] = read_c0_count();
585 			return 0;
586 		case 3:		/* Count register resolution */
587 			switch (current_cpu_data.cputype) {
588 			case CPU_20KC:
589 			case CPU_25KF:
590 				regs->regs[rt] = 1;
591 				break;
592 			default:
593 				regs->regs[rt] = 2;
594 			}
595 			return 0;
596 		case 29:
597 			regs->regs[rt] = ti->tp_value;
598 			return 0;
599 		default:
600 			return -1;
601 		}
602 	}
603 
604 	/* Not ours.  */
605 	return -1;
606 }
607 
608 static int simulate_sync(struct pt_regs *regs, unsigned int opcode)
609 {
610 	if ((opcode & OPCODE) == SPEC0 && (opcode & FUNC) == SYNC)
611 		return 0;
612 
613 	return -1;			/* Must be something else ... */
614 }
615 
616 asmlinkage void do_ov(struct pt_regs *regs)
617 {
618 	siginfo_t info;
619 
620 	die_if_kernel("Integer overflow", regs);
621 
622 	info.si_code = FPE_INTOVF;
623 	info.si_signo = SIGFPE;
624 	info.si_errno = 0;
625 	info.si_addr = (void __user *) regs->cp0_epc;
626 	force_sig_info(SIGFPE, &info, current);
627 }
628 
629 /*
630  * XXX Delayed fp exceptions when doing a lazy ctx switch XXX
631  */
632 asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
633 {
634 	siginfo_t info;
635 
636 	if (notify_die(DIE_FP, "FP exception", regs, SIGFPE, 0, 0)
637 	    == NOTIFY_STOP)
638 		return;
639 	die_if_kernel("FP exception in kernel code", regs);
640 
641 	if (fcr31 & FPU_CSR_UNI_X) {
642 		int sig;
643 
644 		/*
645 		 * Unimplemented operation exception.  If we've got the full
646 		 * software emulator on-board, let's use it...
647 		 *
648 		 * Force FPU to dump state into task/thread context.  We're
649 		 * moving a lot of data here for what is probably a single
650 		 * instruction, but the alternative is to pre-decode the FP
651 		 * register operands before invoking the emulator, which seems
652 		 * a bit extreme for what should be an infrequent event.
653 		 */
654 		/* Ensure 'resume' not overwrite saved fp context again. */
655 		lose_fpu(1);
656 
657 		/* Run the emulator */
658 		sig = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1);
659 
660 		/*
661 		 * We can't allow the emulated instruction to leave any of
662 		 * the cause bit set in $fcr31.
663 		 */
664 		current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
665 
666 		/* Restore the hardware register state */
667 		own_fpu(1);	/* Using the FPU again.  */
668 
669 		/* If something went wrong, signal */
670 		if (sig)
671 			force_sig(sig, current);
672 
673 		return;
674 	} else if (fcr31 & FPU_CSR_INV_X)
675 		info.si_code = FPE_FLTINV;
676 	else if (fcr31 & FPU_CSR_DIV_X)
677 		info.si_code = FPE_FLTDIV;
678 	else if (fcr31 & FPU_CSR_OVF_X)
679 		info.si_code = FPE_FLTOVF;
680 	else if (fcr31 & FPU_CSR_UDF_X)
681 		info.si_code = FPE_FLTUND;
682 	else if (fcr31 & FPU_CSR_INE_X)
683 		info.si_code = FPE_FLTRES;
684 	else
685 		info.si_code = __SI_FAULT;
686 	info.si_signo = SIGFPE;
687 	info.si_errno = 0;
688 	info.si_addr = (void __user *) regs->cp0_epc;
689 	force_sig_info(SIGFPE, &info, current);
690 }
691 
692 static void do_trap_or_bp(struct pt_regs *regs, unsigned int code,
693 	const char *str)
694 {
695 	siginfo_t info;
696 	char b[40];
697 
698 	if (notify_die(DIE_TRAP, str, regs, code, 0, 0) == NOTIFY_STOP)
699 		return;
700 
701 	/*
702 	 * A short test says that IRIX 5.3 sends SIGTRAP for all trap
703 	 * insns, even for trap and break codes that indicate arithmetic
704 	 * failures.  Weird ...
705 	 * But should we continue the brokenness???  --macro
706 	 */
707 	switch (code) {
708 	case BRK_OVERFLOW:
709 	case BRK_DIVZERO:
710 		scnprintf(b, sizeof(b), "%s instruction in kernel code", str);
711 		die_if_kernel(b, regs);
712 		if (code == BRK_DIVZERO)
713 			info.si_code = FPE_INTDIV;
714 		else
715 			info.si_code = FPE_INTOVF;
716 		info.si_signo = SIGFPE;
717 		info.si_errno = 0;
718 		info.si_addr = (void __user *) regs->cp0_epc;
719 		force_sig_info(SIGFPE, &info, current);
720 		break;
721 	case BRK_BUG:
722 		die_if_kernel("Kernel bug detected", regs);
723 		force_sig(SIGTRAP, current);
724 		break;
725 	default:
726 		scnprintf(b, sizeof(b), "%s instruction in kernel code", str);
727 		die_if_kernel(b, regs);
728 		force_sig(SIGTRAP, current);
729 	}
730 }
731 
732 asmlinkage void do_bp(struct pt_regs *regs)
733 {
734 	unsigned int opcode, bcode;
735 
736 	if (__get_user(opcode, (unsigned int __user *) exception_epc(regs)))
737 		goto out_sigsegv;
738 
739 	/*
740 	 * There is the ancient bug in the MIPS assemblers that the break
741 	 * code starts left to bit 16 instead to bit 6 in the opcode.
742 	 * Gas is bug-compatible, but not always, grrr...
743 	 * We handle both cases with a simple heuristics.  --macro
744 	 */
745 	bcode = ((opcode >> 6) & ((1 << 20) - 1));
746 	if (bcode >= (1 << 10))
747 		bcode >>= 10;
748 
749 	do_trap_or_bp(regs, bcode, "Break");
750 	return;
751 
752 out_sigsegv:
753 	force_sig(SIGSEGV, current);
754 }
755 
756 asmlinkage void do_tr(struct pt_regs *regs)
757 {
758 	unsigned int opcode, tcode = 0;
759 
760 	if (__get_user(opcode, (unsigned int __user *) exception_epc(regs)))
761 		goto out_sigsegv;
762 
763 	/* Immediate versions don't provide a code.  */
764 	if (!(opcode & OPCODE))
765 		tcode = ((opcode >> 6) & ((1 << 10) - 1));
766 
767 	do_trap_or_bp(regs, tcode, "Trap");
768 	return;
769 
770 out_sigsegv:
771 	force_sig(SIGSEGV, current);
772 }
773 
774 asmlinkage void do_ri(struct pt_regs *regs)
775 {
776 	unsigned int __user *epc = (unsigned int __user *)exception_epc(regs);
777 	unsigned long old_epc = regs->cp0_epc;
778 	unsigned int opcode = 0;
779 	int status = -1;
780 
781 	if (notify_die(DIE_RI, "RI Fault", regs, SIGSEGV, 0, 0)
782 	    == NOTIFY_STOP)
783 		return;
784 
785 	die_if_kernel("Reserved instruction in kernel code", regs);
786 
787 	if (unlikely(compute_return_epc(regs) < 0))
788 		return;
789 
790 	if (unlikely(get_user(opcode, epc) < 0))
791 		status = SIGSEGV;
792 
793 	if (!cpu_has_llsc && status < 0)
794 		status = simulate_llsc(regs, opcode);
795 
796 	if (status < 0)
797 		status = simulate_rdhwr(regs, opcode);
798 
799 	if (status < 0)
800 		status = simulate_sync(regs, opcode);
801 
802 	if (status < 0)
803 		status = SIGILL;
804 
805 	if (unlikely(status > 0)) {
806 		regs->cp0_epc = old_epc;		/* Undo skip-over.  */
807 		force_sig(status, current);
808 	}
809 }
810 
811 /*
812  * MIPS MT processors may have fewer FPU contexts than CPU threads. If we've
813  * emulated more than some threshold number of instructions, force migration to
814  * a "CPU" that has FP support.
815  */
816 static void mt_ase_fp_affinity(void)
817 {
818 #ifdef CONFIG_MIPS_MT_FPAFF
819 	if (mt_fpemul_threshold > 0 &&
820 	     ((current->thread.emulated_fp++ > mt_fpemul_threshold))) {
821 		/*
822 		 * If there's no FPU present, or if the application has already
823 		 * restricted the allowed set to exclude any CPUs with FPUs,
824 		 * we'll skip the procedure.
825 		 */
826 		if (cpus_intersects(current->cpus_allowed, mt_fpu_cpumask)) {
827 			cpumask_t tmask;
828 
829 			current->thread.user_cpus_allowed
830 				= current->cpus_allowed;
831 			cpus_and(tmask, current->cpus_allowed,
832 				mt_fpu_cpumask);
833 			set_cpus_allowed(current, tmask);
834 			set_thread_flag(TIF_FPUBOUND);
835 		}
836 	}
837 #endif /* CONFIG_MIPS_MT_FPAFF */
838 }
839 
840 asmlinkage void do_cpu(struct pt_regs *regs)
841 {
842 	unsigned int __user *epc;
843 	unsigned long old_epc;
844 	unsigned int opcode;
845 	unsigned int cpid;
846 	int status;
847 
848 	die_if_kernel("do_cpu invoked from kernel context!", regs);
849 
850 	cpid = (regs->cp0_cause >> CAUSEB_CE) & 3;
851 
852 	switch (cpid) {
853 	case 0:
854 		epc = (unsigned int __user *)exception_epc(regs);
855 		old_epc = regs->cp0_epc;
856 		opcode = 0;
857 		status = -1;
858 
859 		if (unlikely(compute_return_epc(regs) < 0))
860 			return;
861 
862 		if (unlikely(get_user(opcode, epc) < 0))
863 			status = SIGSEGV;
864 
865 		if (!cpu_has_llsc && status < 0)
866 			status = simulate_llsc(regs, opcode);
867 
868 		if (status < 0)
869 			status = simulate_rdhwr(regs, opcode);
870 
871 		if (status < 0)
872 			status = SIGILL;
873 
874 		if (unlikely(status > 0)) {
875 			regs->cp0_epc = old_epc;	/* Undo skip-over.  */
876 			force_sig(status, current);
877 		}
878 
879 		return;
880 
881 	case 1:
882 		if (used_math())	/* Using the FPU again.  */
883 			own_fpu(1);
884 		else {			/* First time FPU user.  */
885 			init_fpu();
886 			set_used_math();
887 		}
888 
889 		if (!raw_cpu_has_fpu) {
890 			int sig;
891 			sig = fpu_emulator_cop1Handler(regs,
892 						&current->thread.fpu, 0);
893 			if (sig)
894 				force_sig(sig, current);
895 			else
896 				mt_ase_fp_affinity();
897 		}
898 
899 		return;
900 
901 	case 2:
902 	case 3:
903 		break;
904 	}
905 
906 	force_sig(SIGILL, current);
907 }
908 
909 asmlinkage void do_mdmx(struct pt_regs *regs)
910 {
911 	force_sig(SIGILL, current);
912 }
913 
914 asmlinkage void do_watch(struct pt_regs *regs)
915 {
916 	u32 cause;
917 
918 	/*
919 	 * Clear WP (bit 22) bit of cause register so we don't loop
920 	 * forever.
921 	 */
922 	cause = read_c0_cause();
923 	cause &= ~(1 << 22);
924 	write_c0_cause(cause);
925 
926 	/*
927 	 * If the current thread has the watch registers loaded, save
928 	 * their values and send SIGTRAP.  Otherwise another thread
929 	 * left the registers set, clear them and continue.
930 	 */
931 	if (test_tsk_thread_flag(current, TIF_LOAD_WATCH)) {
932 		mips_read_watch_registers();
933 		force_sig(SIGTRAP, current);
934 	} else
935 		mips_clear_watch_registers();
936 }
937 
938 asmlinkage void do_mcheck(struct pt_regs *regs)
939 {
940 	const int field = 2 * sizeof(unsigned long);
941 	int multi_match = regs->cp0_status & ST0_TS;
942 
943 	show_regs(regs);
944 
945 	if (multi_match) {
946 		printk("Index   : %0x\n", read_c0_index());
947 		printk("Pagemask: %0x\n", read_c0_pagemask());
948 		printk("EntryHi : %0*lx\n", field, read_c0_entryhi());
949 		printk("EntryLo0: %0*lx\n", field, read_c0_entrylo0());
950 		printk("EntryLo1: %0*lx\n", field, read_c0_entrylo1());
951 		printk("\n");
952 		dump_tlb_all();
953 	}
954 
955 	show_code((unsigned int __user *) regs->cp0_epc);
956 
957 	/*
958 	 * Some chips may have other causes of machine check (e.g. SB1
959 	 * graduation timer)
960 	 */
961 	panic("Caught Machine Check exception - %scaused by multiple "
962 	      "matching entries in the TLB.",
963 	      (multi_match) ? "" : "not ");
964 }
965 
966 asmlinkage void do_mt(struct pt_regs *regs)
967 {
968 	int subcode;
969 
970 	subcode = (read_vpe_c0_vpecontrol() & VPECONTROL_EXCPT)
971 			>> VPECONTROL_EXCPT_SHIFT;
972 	switch (subcode) {
973 	case 0:
974 		printk(KERN_DEBUG "Thread Underflow\n");
975 		break;
976 	case 1:
977 		printk(KERN_DEBUG "Thread Overflow\n");
978 		break;
979 	case 2:
980 		printk(KERN_DEBUG "Invalid YIELD Qualifier\n");
981 		break;
982 	case 3:
983 		printk(KERN_DEBUG "Gating Storage Exception\n");
984 		break;
985 	case 4:
986 		printk(KERN_DEBUG "YIELD Scheduler Exception\n");
987 		break;
988 	case 5:
989 		printk(KERN_DEBUG "Gating Storage Schedulier Exception\n");
990 		break;
991 	default:
992 		printk(KERN_DEBUG "*** UNKNOWN THREAD EXCEPTION %d ***\n",
993 			subcode);
994 		break;
995 	}
996 	die_if_kernel("MIPS MT Thread exception in kernel", regs);
997 
998 	force_sig(SIGILL, current);
999 }
1000 
1001 
1002 asmlinkage void do_dsp(struct pt_regs *regs)
1003 {
1004 	if (cpu_has_dsp)
1005 		panic("Unexpected DSP exception\n");
1006 
1007 	force_sig(SIGILL, current);
1008 }
1009 
1010 asmlinkage void do_reserved(struct pt_regs *regs)
1011 {
1012 	/*
1013 	 * Game over - no way to handle this if it ever occurs.  Most probably
1014 	 * caused by a new unknown cpu type or after another deadly
1015 	 * hard/software error.
1016 	 */
1017 	show_regs(regs);
1018 	panic("Caught reserved exception %ld - should not happen.",
1019 	      (regs->cp0_cause & 0x7f) >> 2);
1020 }
1021 
1022 static int __initdata l1parity = 1;
1023 static int __init nol1parity(char *s)
1024 {
1025 	l1parity = 0;
1026 	return 1;
1027 }
1028 __setup("nol1par", nol1parity);
1029 static int __initdata l2parity = 1;
1030 static int __init nol2parity(char *s)
1031 {
1032 	l2parity = 0;
1033 	return 1;
1034 }
1035 __setup("nol2par", nol2parity);
1036 
1037 /*
1038  * Some MIPS CPUs can enable/disable for cache parity detection, but do
1039  * it different ways.
1040  */
1041 static inline void parity_protection_init(void)
1042 {
1043 	switch (current_cpu_type()) {
1044 	case CPU_24K:
1045 	case CPU_34K:
1046 	case CPU_74K:
1047 	case CPU_1004K:
1048 		{
1049 #define ERRCTL_PE	0x80000000
1050 #define ERRCTL_L2P	0x00800000
1051 			unsigned long errctl;
1052 			unsigned int l1parity_present, l2parity_present;
1053 
1054 			errctl = read_c0_ecc();
1055 			errctl &= ~(ERRCTL_PE|ERRCTL_L2P);
1056 
1057 			/* probe L1 parity support */
1058 			write_c0_ecc(errctl | ERRCTL_PE);
1059 			back_to_back_c0_hazard();
1060 			l1parity_present = (read_c0_ecc() & ERRCTL_PE);
1061 
1062 			/* probe L2 parity support */
1063 			write_c0_ecc(errctl|ERRCTL_L2P);
1064 			back_to_back_c0_hazard();
1065 			l2parity_present = (read_c0_ecc() & ERRCTL_L2P);
1066 
1067 			if (l1parity_present && l2parity_present) {
1068 				if (l1parity)
1069 					errctl |= ERRCTL_PE;
1070 				if (l1parity ^ l2parity)
1071 					errctl |= ERRCTL_L2P;
1072 			} else if (l1parity_present) {
1073 				if (l1parity)
1074 					errctl |= ERRCTL_PE;
1075 			} else if (l2parity_present) {
1076 				if (l2parity)
1077 					errctl |= ERRCTL_L2P;
1078 			} else {
1079 				/* No parity available */
1080 			}
1081 
1082 			printk(KERN_INFO "Writing ErrCtl register=%08lx\n", errctl);
1083 
1084 			write_c0_ecc(errctl);
1085 			back_to_back_c0_hazard();
1086 			errctl = read_c0_ecc();
1087 			printk(KERN_INFO "Readback ErrCtl register=%08lx\n", errctl);
1088 
1089 			if (l1parity_present)
1090 				printk(KERN_INFO "Cache parity protection %sabled\n",
1091 				       (errctl & ERRCTL_PE) ? "en" : "dis");
1092 
1093 			if (l2parity_present) {
1094 				if (l1parity_present && l1parity)
1095 					errctl ^= ERRCTL_L2P;
1096 				printk(KERN_INFO "L2 cache parity protection %sabled\n",
1097 				       (errctl & ERRCTL_L2P) ? "en" : "dis");
1098 			}
1099 		}
1100 		break;
1101 
1102 	case CPU_5KC:
1103 		write_c0_ecc(0x80000000);
1104 		back_to_back_c0_hazard();
1105 		/* Set the PE bit (bit 31) in the c0_errctl register. */
1106 		printk(KERN_INFO "Cache parity protection %sabled\n",
1107 		       (read_c0_ecc() & 0x80000000) ? "en" : "dis");
1108 		break;
1109 	case CPU_20KC:
1110 	case CPU_25KF:
1111 		/* Clear the DE bit (bit 16) in the c0_status register. */
1112 		printk(KERN_INFO "Enable cache parity protection for "
1113 		       "MIPS 20KC/25KF CPUs.\n");
1114 		clear_c0_status(ST0_DE);
1115 		break;
1116 	default:
1117 		break;
1118 	}
1119 }
1120 
1121 asmlinkage void cache_parity_error(void)
1122 {
1123 	const int field = 2 * sizeof(unsigned long);
1124 	unsigned int reg_val;
1125 
1126 	/* For the moment, report the problem and hang. */
1127 	printk("Cache error exception:\n");
1128 	printk("cp0_errorepc == %0*lx\n", field, read_c0_errorepc());
1129 	reg_val = read_c0_cacheerr();
1130 	printk("c0_cacheerr == %08x\n", reg_val);
1131 
1132 	printk("Decoded c0_cacheerr: %s cache fault in %s reference.\n",
1133 	       reg_val & (1<<30) ? "secondary" : "primary",
1134 	       reg_val & (1<<31) ? "data" : "insn");
1135 	printk("Error bits: %s%s%s%s%s%s%s\n",
1136 	       reg_val & (1<<29) ? "ED " : "",
1137 	       reg_val & (1<<28) ? "ET " : "",
1138 	       reg_val & (1<<26) ? "EE " : "",
1139 	       reg_val & (1<<25) ? "EB " : "",
1140 	       reg_val & (1<<24) ? "EI " : "",
1141 	       reg_val & (1<<23) ? "E1 " : "",
1142 	       reg_val & (1<<22) ? "E0 " : "");
1143 	printk("IDX: 0x%08x\n", reg_val & ((1<<22)-1));
1144 
1145 #if defined(CONFIG_CPU_MIPS32) || defined(CONFIG_CPU_MIPS64)
1146 	if (reg_val & (1<<22))
1147 		printk("DErrAddr0: 0x%0*lx\n", field, read_c0_derraddr0());
1148 
1149 	if (reg_val & (1<<23))
1150 		printk("DErrAddr1: 0x%0*lx\n", field, read_c0_derraddr1());
1151 #endif
1152 
1153 	panic("Can't handle the cache error!");
1154 }
1155 
1156 /*
1157  * SDBBP EJTAG debug exception handler.
1158  * We skip the instruction and return to the next instruction.
1159  */
1160 void ejtag_exception_handler(struct pt_regs *regs)
1161 {
1162 	const int field = 2 * sizeof(unsigned long);
1163 	unsigned long depc, old_epc;
1164 	unsigned int debug;
1165 
1166 	printk(KERN_DEBUG "SDBBP EJTAG debug exception - not handled yet, just ignored!\n");
1167 	depc = read_c0_depc();
1168 	debug = read_c0_debug();
1169 	printk(KERN_DEBUG "c0_depc = %0*lx, DEBUG = %08x\n", field, depc, debug);
1170 	if (debug & 0x80000000) {
1171 		/*
1172 		 * In branch delay slot.
1173 		 * We cheat a little bit here and use EPC to calculate the
1174 		 * debug return address (DEPC). EPC is restored after the
1175 		 * calculation.
1176 		 */
1177 		old_epc = regs->cp0_epc;
1178 		regs->cp0_epc = depc;
1179 		__compute_return_epc(regs);
1180 		depc = regs->cp0_epc;
1181 		regs->cp0_epc = old_epc;
1182 	} else
1183 		depc += 4;
1184 	write_c0_depc(depc);
1185 
1186 #if 0
1187 	printk(KERN_DEBUG "\n\n----- Enable EJTAG single stepping ----\n\n");
1188 	write_c0_debug(debug | 0x100);
1189 #endif
1190 }
1191 
1192 /*
1193  * NMI exception handler.
1194  */
1195 NORET_TYPE void ATTRIB_NORET nmi_exception_handler(struct pt_regs *regs)
1196 {
1197 	bust_spinlocks(1);
1198 	printk("NMI taken!!!!\n");
1199 	die("NMI", regs);
1200 }
1201 
1202 #define VECTORSPACING 0x100	/* for EI/VI mode */
1203 
1204 unsigned long ebase;
1205 unsigned long exception_handlers[32];
1206 unsigned long vi_handlers[64];
1207 
1208 /*
1209  * As a side effect of the way this is implemented we're limited
1210  * to interrupt handlers in the address range from
1211  * KSEG0 <= x < KSEG0 + 256mb on the Nevada.  Oh well ...
1212  */
1213 void *set_except_vector(int n, void *addr)
1214 {
1215 	unsigned long handler = (unsigned long) addr;
1216 	unsigned long old_handler = exception_handlers[n];
1217 
1218 	exception_handlers[n] = handler;
1219 	if (n == 0 && cpu_has_divec) {
1220 		*(u32 *)(ebase + 0x200) = 0x08000000 |
1221 					  (0x03ffffff & (handler >> 2));
1222 		local_flush_icache_range(ebase + 0x200, ebase + 0x204);
1223 	}
1224 	return (void *)old_handler;
1225 }
1226 
1227 static asmlinkage void do_default_vi(void)
1228 {
1229 	show_regs(get_irq_regs());
1230 	panic("Caught unexpected vectored interrupt.");
1231 }
1232 
1233 static void *set_vi_srs_handler(int n, vi_handler_t addr, int srs)
1234 {
1235 	unsigned long handler;
1236 	unsigned long old_handler = vi_handlers[n];
1237 	int srssets = current_cpu_data.srsets;
1238 	u32 *w;
1239 	unsigned char *b;
1240 
1241 	if (!cpu_has_veic && !cpu_has_vint)
1242 		BUG();
1243 
1244 	if (addr == NULL) {
1245 		handler = (unsigned long) do_default_vi;
1246 		srs = 0;
1247 	} else
1248 		handler = (unsigned long) addr;
1249 	vi_handlers[n] = (unsigned long) addr;
1250 
1251 	b = (unsigned char *)(ebase + 0x200 + n*VECTORSPACING);
1252 
1253 	if (srs >= srssets)
1254 		panic("Shadow register set %d not supported", srs);
1255 
1256 	if (cpu_has_veic) {
1257 		if (board_bind_eic_interrupt)
1258 			board_bind_eic_interrupt(n, srs);
1259 	} else if (cpu_has_vint) {
1260 		/* SRSMap is only defined if shadow sets are implemented */
1261 		if (srssets > 1)
1262 			change_c0_srsmap(0xf << n*4, srs << n*4);
1263 	}
1264 
1265 	if (srs == 0) {
1266 		/*
1267 		 * If no shadow set is selected then use the default handler
1268 		 * that does normal register saving and a standard interrupt exit
1269 		 */
1270 
1271 		extern char except_vec_vi, except_vec_vi_lui;
1272 		extern char except_vec_vi_ori, except_vec_vi_end;
1273 		extern char rollback_except_vec_vi;
1274 		char *vec_start = (cpu_wait == r4k_wait) ?
1275 			&rollback_except_vec_vi : &except_vec_vi;
1276 #ifdef CONFIG_MIPS_MT_SMTC
1277 		/*
1278 		 * We need to provide the SMTC vectored interrupt handler
1279 		 * not only with the address of the handler, but with the
1280 		 * Status.IM bit to be masked before going there.
1281 		 */
1282 		extern char except_vec_vi_mori;
1283 		const int mori_offset = &except_vec_vi_mori - vec_start;
1284 #endif /* CONFIG_MIPS_MT_SMTC */
1285 		const int handler_len = &except_vec_vi_end - vec_start;
1286 		const int lui_offset = &except_vec_vi_lui - vec_start;
1287 		const int ori_offset = &except_vec_vi_ori - vec_start;
1288 
1289 		if (handler_len > VECTORSPACING) {
1290 			/*
1291 			 * Sigh... panicing won't help as the console
1292 			 * is probably not configured :(
1293 			 */
1294 			panic("VECTORSPACING too small");
1295 		}
1296 
1297 		memcpy(b, vec_start, handler_len);
1298 #ifdef CONFIG_MIPS_MT_SMTC
1299 		BUG_ON(n > 7);	/* Vector index %d exceeds SMTC maximum. */
1300 
1301 		w = (u32 *)(b + mori_offset);
1302 		*w = (*w & 0xffff0000) | (0x100 << n);
1303 #endif /* CONFIG_MIPS_MT_SMTC */
1304 		w = (u32 *)(b + lui_offset);
1305 		*w = (*w & 0xffff0000) | (((u32)handler >> 16) & 0xffff);
1306 		w = (u32 *)(b + ori_offset);
1307 		*w = (*w & 0xffff0000) | ((u32)handler & 0xffff);
1308 		local_flush_icache_range((unsigned long)b,
1309 					 (unsigned long)(b+handler_len));
1310 	}
1311 	else {
1312 		/*
1313 		 * In other cases jump directly to the interrupt handler
1314 		 *
1315 		 * It is the handlers responsibility to save registers if required
1316 		 * (eg hi/lo) and return from the exception using "eret"
1317 		 */
1318 		w = (u32 *)b;
1319 		*w++ = 0x08000000 | (((u32)handler >> 2) & 0x03fffff); /* j handler */
1320 		*w = 0;
1321 		local_flush_icache_range((unsigned long)b,
1322 					 (unsigned long)(b+8));
1323 	}
1324 
1325 	return (void *)old_handler;
1326 }
1327 
1328 void *set_vi_handler(int n, vi_handler_t addr)
1329 {
1330 	return set_vi_srs_handler(n, addr, 0);
1331 }
1332 
1333 /*
1334  * This is used by native signal handling
1335  */
1336 asmlinkage int (*save_fp_context)(struct sigcontext __user *sc);
1337 asmlinkage int (*restore_fp_context)(struct sigcontext __user *sc);
1338 
1339 extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
1340 extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
1341 
1342 extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc);
1343 extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc);
1344 
1345 #ifdef CONFIG_SMP
1346 static int smp_save_fp_context(struct sigcontext __user *sc)
1347 {
1348 	return raw_cpu_has_fpu
1349 	       ? _save_fp_context(sc)
1350 	       : fpu_emulator_save_context(sc);
1351 }
1352 
1353 static int smp_restore_fp_context(struct sigcontext __user *sc)
1354 {
1355 	return raw_cpu_has_fpu
1356 	       ? _restore_fp_context(sc)
1357 	       : fpu_emulator_restore_context(sc);
1358 }
1359 #endif
1360 
1361 static inline void signal_init(void)
1362 {
1363 #ifdef CONFIG_SMP
1364 	/* For now just do the cpu_has_fpu check when the functions are invoked */
1365 	save_fp_context = smp_save_fp_context;
1366 	restore_fp_context = smp_restore_fp_context;
1367 #else
1368 	if (cpu_has_fpu) {
1369 		save_fp_context = _save_fp_context;
1370 		restore_fp_context = _restore_fp_context;
1371 	} else {
1372 		save_fp_context = fpu_emulator_save_context;
1373 		restore_fp_context = fpu_emulator_restore_context;
1374 	}
1375 #endif
1376 }
1377 
1378 #ifdef CONFIG_MIPS32_COMPAT
1379 
1380 /*
1381  * This is used by 32-bit signal stuff on the 64-bit kernel
1382  */
1383 asmlinkage int (*save_fp_context32)(struct sigcontext32 __user *sc);
1384 asmlinkage int (*restore_fp_context32)(struct sigcontext32 __user *sc);
1385 
1386 extern asmlinkage int _save_fp_context32(struct sigcontext32 __user *sc);
1387 extern asmlinkage int _restore_fp_context32(struct sigcontext32 __user *sc);
1388 
1389 extern asmlinkage int fpu_emulator_save_context32(struct sigcontext32 __user *sc);
1390 extern asmlinkage int fpu_emulator_restore_context32(struct sigcontext32 __user *sc);
1391 
1392 static inline void signal32_init(void)
1393 {
1394 	if (cpu_has_fpu) {
1395 		save_fp_context32 = _save_fp_context32;
1396 		restore_fp_context32 = _restore_fp_context32;
1397 	} else {
1398 		save_fp_context32 = fpu_emulator_save_context32;
1399 		restore_fp_context32 = fpu_emulator_restore_context32;
1400 	}
1401 }
1402 #endif
1403 
1404 extern void cpu_cache_init(void);
1405 extern void tlb_init(void);
1406 extern void flush_tlb_handlers(void);
1407 
1408 /*
1409  * Timer interrupt
1410  */
1411 int cp0_compare_irq;
1412 
1413 /*
1414  * Performance counter IRQ or -1 if shared with timer
1415  */
1416 int cp0_perfcount_irq;
1417 EXPORT_SYMBOL_GPL(cp0_perfcount_irq);
1418 
1419 static int __cpuinitdata noulri;
1420 
1421 static int __init ulri_disable(char *s)
1422 {
1423 	pr_info("Disabling ulri\n");
1424 	noulri = 1;
1425 
1426 	return 1;
1427 }
1428 __setup("noulri", ulri_disable);
1429 
1430 void __cpuinit per_cpu_trap_init(void)
1431 {
1432 	unsigned int cpu = smp_processor_id();
1433 	unsigned int status_set = ST0_CU0;
1434 #ifdef CONFIG_MIPS_MT_SMTC
1435 	int secondaryTC = 0;
1436 	int bootTC = (cpu == 0);
1437 
1438 	/*
1439 	 * Only do per_cpu_trap_init() for first TC of Each VPE.
1440 	 * Note that this hack assumes that the SMTC init code
1441 	 * assigns TCs consecutively and in ascending order.
1442 	 */
1443 
1444 	if (((read_c0_tcbind() & TCBIND_CURTC) != 0) &&
1445 	    ((read_c0_tcbind() & TCBIND_CURVPE) == cpu_data[cpu - 1].vpe_id))
1446 		secondaryTC = 1;
1447 #endif /* CONFIG_MIPS_MT_SMTC */
1448 
1449 	/*
1450 	 * Disable coprocessors and select 32-bit or 64-bit addressing
1451 	 * and the 16/32 or 32/32 FPR register model.  Reset the BEV
1452 	 * flag that some firmware may have left set and the TS bit (for
1453 	 * IP27).  Set XX for ISA IV code to work.
1454 	 */
1455 #ifdef CONFIG_64BIT
1456 	status_set |= ST0_FR|ST0_KX|ST0_SX|ST0_UX;
1457 #endif
1458 	if (current_cpu_data.isa_level == MIPS_CPU_ISA_IV)
1459 		status_set |= ST0_XX;
1460 	if (cpu_has_dsp)
1461 		status_set |= ST0_MX;
1462 
1463 	change_c0_status(ST0_CU|ST0_MX|ST0_RE|ST0_FR|ST0_BEV|ST0_TS|ST0_KX|ST0_SX|ST0_UX,
1464 			 status_set);
1465 
1466 	if (cpu_has_mips_r2) {
1467 		unsigned int enable = 0x0000000f;
1468 
1469 		if (!noulri && cpu_has_userlocal)
1470 			enable |= (1 << 29);
1471 
1472 		write_c0_hwrena(enable);
1473 	}
1474 
1475 #ifdef CONFIG_MIPS_MT_SMTC
1476 	if (!secondaryTC) {
1477 #endif /* CONFIG_MIPS_MT_SMTC */
1478 
1479 	if (cpu_has_veic || cpu_has_vint) {
1480 		write_c0_ebase(ebase);
1481 		/* Setting vector spacing enables EI/VI mode  */
1482 		change_c0_intctl(0x3e0, VECTORSPACING);
1483 	}
1484 	if (cpu_has_divec) {
1485 		if (cpu_has_mipsmt) {
1486 			unsigned int vpflags = dvpe();
1487 			set_c0_cause(CAUSEF_IV);
1488 			evpe(vpflags);
1489 		} else
1490 			set_c0_cause(CAUSEF_IV);
1491 	}
1492 
1493 	/*
1494 	 * Before R2 both interrupt numbers were fixed to 7, so on R2 only:
1495 	 *
1496 	 *  o read IntCtl.IPTI to determine the timer interrupt
1497 	 *  o read IntCtl.IPPCI to determine the performance counter interrupt
1498 	 */
1499 	if (cpu_has_mips_r2) {
1500 		cp0_compare_irq = (read_c0_intctl() >> 29) & 7;
1501 		cp0_perfcount_irq = (read_c0_intctl() >> 26) & 7;
1502 		if (cp0_perfcount_irq == cp0_compare_irq)
1503 			cp0_perfcount_irq = -1;
1504 	} else {
1505 		cp0_compare_irq = CP0_LEGACY_COMPARE_IRQ;
1506 		cp0_perfcount_irq = -1;
1507 	}
1508 
1509 #ifdef CONFIG_MIPS_MT_SMTC
1510 	}
1511 #endif /* CONFIG_MIPS_MT_SMTC */
1512 
1513 	cpu_data[cpu].asid_cache = ASID_FIRST_VERSION;
1514 	TLBMISS_HANDLER_SETUP();
1515 
1516 	atomic_inc(&init_mm.mm_count);
1517 	current->active_mm = &init_mm;
1518 	BUG_ON(current->mm);
1519 	enter_lazy_tlb(&init_mm, current);
1520 
1521 #ifdef CONFIG_MIPS_MT_SMTC
1522 	if (bootTC) {
1523 #endif /* CONFIG_MIPS_MT_SMTC */
1524 		cpu_cache_init();
1525 		tlb_init();
1526 #ifdef CONFIG_MIPS_MT_SMTC
1527 	} else if (!secondaryTC) {
1528 		/*
1529 		 * First TC in non-boot VPE must do subset of tlb_init()
1530 		 * for MMU countrol registers.
1531 		 */
1532 		write_c0_pagemask(PM_DEFAULT_MASK);
1533 		write_c0_wired(0);
1534 	}
1535 #endif /* CONFIG_MIPS_MT_SMTC */
1536 }
1537 
1538 /* Install CPU exception handler */
1539 void __init set_handler(unsigned long offset, void *addr, unsigned long size)
1540 {
1541 	memcpy((void *)(ebase + offset), addr, size);
1542 	local_flush_icache_range(ebase + offset, ebase + offset + size);
1543 }
1544 
1545 static char panic_null_cerr[] __cpuinitdata =
1546 	"Trying to set NULL cache error exception handler";
1547 
1548 /* Install uncached CPU exception handler */
1549 void __cpuinit set_uncached_handler(unsigned long offset, void *addr,
1550 	unsigned long size)
1551 {
1552 #ifdef CONFIG_32BIT
1553 	unsigned long uncached_ebase = KSEG1ADDR(ebase);
1554 #endif
1555 #ifdef CONFIG_64BIT
1556 	unsigned long uncached_ebase = TO_UNCAC(ebase);
1557 #endif
1558 
1559 	if (!addr)
1560 		panic(panic_null_cerr);
1561 
1562 	memcpy((void *)(uncached_ebase + offset), addr, size);
1563 }
1564 
1565 static int __initdata rdhwr_noopt;
1566 static int __init set_rdhwr_noopt(char *str)
1567 {
1568 	rdhwr_noopt = 1;
1569 	return 1;
1570 }
1571 
1572 __setup("rdhwr_noopt", set_rdhwr_noopt);
1573 
1574 void __init trap_init(void)
1575 {
1576 	extern char except_vec3_generic, except_vec3_r4000;
1577 	extern char except_vec4;
1578 	unsigned long i;
1579 	int rollback;
1580 
1581 	check_wait();
1582 	rollback = (cpu_wait == r4k_wait);
1583 
1584 #if defined(CONFIG_KGDB)
1585 	if (kgdb_early_setup)
1586 		return;	/* Already done */
1587 #endif
1588 
1589 	if (cpu_has_veic || cpu_has_vint)
1590 		ebase = (unsigned long) alloc_bootmem_low_pages(0x200 + VECTORSPACING*64);
1591 	else
1592 		ebase = CAC_BASE;
1593 
1594 	per_cpu_trap_init();
1595 
1596 	/*
1597 	 * Copy the generic exception handlers to their final destination.
1598 	 * This will be overriden later as suitable for a particular
1599 	 * configuration.
1600 	 */
1601 	set_handler(0x180, &except_vec3_generic, 0x80);
1602 
1603 	/*
1604 	 * Setup default vectors
1605 	 */
1606 	for (i = 0; i <= 31; i++)
1607 		set_except_vector(i, handle_reserved);
1608 
1609 	/*
1610 	 * Copy the EJTAG debug exception vector handler code to it's final
1611 	 * destination.
1612 	 */
1613 	if (cpu_has_ejtag && board_ejtag_handler_setup)
1614 		board_ejtag_handler_setup();
1615 
1616 	/*
1617 	 * Only some CPUs have the watch exceptions.
1618 	 */
1619 	if (cpu_has_watch)
1620 		set_except_vector(23, handle_watch);
1621 
1622 	/*
1623 	 * Initialise interrupt handlers
1624 	 */
1625 	if (cpu_has_veic || cpu_has_vint) {
1626 		int nvec = cpu_has_veic ? 64 : 8;
1627 		for (i = 0; i < nvec; i++)
1628 			set_vi_handler(i, NULL);
1629 	}
1630 	else if (cpu_has_divec)
1631 		set_handler(0x200, &except_vec4, 0x8);
1632 
1633 	/*
1634 	 * Some CPUs can enable/disable for cache parity detection, but does
1635 	 * it different ways.
1636 	 */
1637 	parity_protection_init();
1638 
1639 	/*
1640 	 * The Data Bus Errors / Instruction Bus Errors are signaled
1641 	 * by external hardware.  Therefore these two exceptions
1642 	 * may have board specific handlers.
1643 	 */
1644 	if (board_be_init)
1645 		board_be_init();
1646 
1647 	set_except_vector(0, rollback ? rollback_handle_int : handle_int);
1648 	set_except_vector(1, handle_tlbm);
1649 	set_except_vector(2, handle_tlbl);
1650 	set_except_vector(3, handle_tlbs);
1651 
1652 	set_except_vector(4, handle_adel);
1653 	set_except_vector(5, handle_ades);
1654 
1655 	set_except_vector(6, handle_ibe);
1656 	set_except_vector(7, handle_dbe);
1657 
1658 	set_except_vector(8, handle_sys);
1659 	set_except_vector(9, handle_bp);
1660 	set_except_vector(10, rdhwr_noopt ? handle_ri :
1661 			  (cpu_has_vtag_icache ?
1662 			   handle_ri_rdhwr_vivt : handle_ri_rdhwr));
1663 	set_except_vector(11, handle_cpu);
1664 	set_except_vector(12, handle_ov);
1665 	set_except_vector(13, handle_tr);
1666 
1667 	if (current_cpu_type() == CPU_R6000 ||
1668 	    current_cpu_type() == CPU_R6000A) {
1669 		/*
1670 		 * The R6000 is the only R-series CPU that features a machine
1671 		 * check exception (similar to the R4000 cache error) and
1672 		 * unaligned ldc1/sdc1 exception.  The handlers have not been
1673 		 * written yet.  Well, anyway there is no R6000 machine on the
1674 		 * current list of targets for Linux/MIPS.
1675 		 * (Duh, crap, there is someone with a triple R6k machine)
1676 		 */
1677 		//set_except_vector(14, handle_mc);
1678 		//set_except_vector(15, handle_ndc);
1679 	}
1680 
1681 
1682 	if (board_nmi_handler_setup)
1683 		board_nmi_handler_setup();
1684 
1685 	if (cpu_has_fpu && !cpu_has_nofpuex)
1686 		set_except_vector(15, handle_fpe);
1687 
1688 	set_except_vector(22, handle_mdmx);
1689 
1690 	if (cpu_has_mcheck)
1691 		set_except_vector(24, handle_mcheck);
1692 
1693 	if (cpu_has_mipsmt)
1694 		set_except_vector(25, handle_mt);
1695 
1696 	set_except_vector(26, handle_dsp);
1697 
1698 	if (cpu_has_vce)
1699 		/* Special exception: R4[04]00 uses also the divec space. */
1700 		memcpy((void *)(CAC_BASE + 0x180), &except_vec3_r4000, 0x100);
1701 	else if (cpu_has_4kex)
1702 		memcpy((void *)(CAC_BASE + 0x180), &except_vec3_generic, 0x80);
1703 	else
1704 		memcpy((void *)(CAC_BASE + 0x080), &except_vec3_generic, 0x80);
1705 
1706 	signal_init();
1707 #ifdef CONFIG_MIPS32_COMPAT
1708 	signal32_init();
1709 #endif
1710 
1711 	local_flush_icache_range(ebase, ebase + 0x400);
1712 	flush_tlb_handlers();
1713 
1714 	sort_extable(__start___dbe_table, __stop___dbe_table);
1715 }
1716