xref: /openbmc/linux/arch/loongarch/kernel/traps.c (revision 9a29f5fc)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Author: Huacai Chen <chenhuacai@loongson.cn>
4  * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
5  */
6 #include <linux/bitops.h>
7 #include <linux/bug.h>
8 #include <linux/compiler.h>
9 #include <linux/context_tracking.h>
10 #include <linux/entry-common.h>
11 #include <linux/init.h>
12 #include <linux/kernel.h>
13 #include <linux/kexec.h>
14 #include <linux/module.h>
15 #include <linux/extable.h>
16 #include <linux/mm.h>
17 #include <linux/sched/mm.h>
18 #include <linux/sched/debug.h>
19 #include <linux/smp.h>
20 #include <linux/spinlock.h>
21 #include <linux/kallsyms.h>
22 #include <linux/memblock.h>
23 #include <linux/interrupt.h>
24 #include <linux/ptrace.h>
25 #include <linux/kgdb.h>
26 #include <linux/kdebug.h>
27 #include <linux/kprobes.h>
28 #include <linux/notifier.h>
29 #include <linux/irq.h>
30 #include <linux/perf_event.h>
31 
32 #include <asm/addrspace.h>
33 #include <asm/bootinfo.h>
34 #include <asm/branch.h>
35 #include <asm/break.h>
36 #include <asm/cpu.h>
37 #include <asm/fpu.h>
38 #include <asm/loongarch.h>
39 #include <asm/mmu_context.h>
40 #include <asm/pgtable.h>
41 #include <asm/ptrace.h>
42 #include <asm/sections.h>
43 #include <asm/siginfo.h>
44 #include <asm/stacktrace.h>
45 #include <asm/tlb.h>
46 #include <asm/types.h>
47 #include <asm/unwind.h>
48 
49 #include "access-helper.h"
50 
51 extern asmlinkage void handle_ade(void);
52 extern asmlinkage void handle_ale(void);
53 extern asmlinkage void handle_sys(void);
54 extern asmlinkage void handle_bp(void);
55 extern asmlinkage void handle_ri(void);
56 extern asmlinkage void handle_fpu(void);
57 extern asmlinkage void handle_fpe(void);
58 extern asmlinkage void handle_lbt(void);
59 extern asmlinkage void handle_lsx(void);
60 extern asmlinkage void handle_lasx(void);
61 extern asmlinkage void handle_reserved(void);
62 extern asmlinkage void handle_watch(void);
63 extern asmlinkage void handle_vint(void);
64 
65 static void show_backtrace(struct task_struct *task, const struct pt_regs *regs,
66 			   const char *loglvl, bool user)
67 {
68 	unsigned long addr;
69 	struct unwind_state state;
70 	struct pt_regs *pregs = (struct pt_regs *)regs;
71 
72 	if (!task)
73 		task = current;
74 
75 	if (user_mode(regs))
76 		state.type = UNWINDER_GUESS;
77 
78 	printk("%sCall Trace:", loglvl);
79 	for (unwind_start(&state, task, pregs);
80 	      !unwind_done(&state); unwind_next_frame(&state)) {
81 		addr = unwind_get_return_address(&state);
82 		print_ip_sym(loglvl, addr);
83 	}
84 	printk("%s\n", loglvl);
85 }
86 
87 static void show_stacktrace(struct task_struct *task,
88 	const struct pt_regs *regs, const char *loglvl, bool user)
89 {
90 	int i;
91 	const int field = 2 * sizeof(unsigned long);
92 	unsigned long stackdata;
93 	unsigned long *sp = (unsigned long *)regs->regs[3];
94 
95 	printk("%sStack :", loglvl);
96 	i = 0;
97 	while ((unsigned long) sp & (PAGE_SIZE - 1)) {
98 		if (i && ((i % (64 / field)) == 0)) {
99 			pr_cont("\n");
100 			printk("%s       ", loglvl);
101 		}
102 		if (i > 39) {
103 			pr_cont(" ...");
104 			break;
105 		}
106 
107 		if (__get_addr(&stackdata, sp++, user)) {
108 			pr_cont(" (Bad stack address)");
109 			break;
110 		}
111 
112 		pr_cont(" %0*lx", field, stackdata);
113 		i++;
114 	}
115 	pr_cont("\n");
116 	show_backtrace(task, regs, loglvl, user);
117 }
118 
119 void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
120 {
121 	struct pt_regs regs;
122 
123 	regs.csr_crmd = 0;
124 	if (sp) {
125 		regs.csr_era = 0;
126 		regs.regs[1] = 0;
127 		regs.regs[3] = (unsigned long)sp;
128 	} else {
129 		if (!task || task == current)
130 			prepare_frametrace(&regs);
131 		else {
132 			regs.csr_era = task->thread.reg01;
133 			regs.regs[1] = 0;
134 			regs.regs[3] = task->thread.reg03;
135 			regs.regs[22] = task->thread.reg22;
136 		}
137 	}
138 
139 	show_stacktrace(task, &regs, loglvl, false);
140 }
141 
142 static void show_code(unsigned int *pc, bool user)
143 {
144 	long i;
145 	unsigned int insn;
146 
147 	printk("Code:");
148 
149 	for(i = -3 ; i < 6 ; i++) {
150 		if (__get_inst(&insn, pc + i, user)) {
151 			pr_cont(" (Bad address in era)\n");
152 			break;
153 		}
154 		pr_cont("%c%08x%c", (i?' ':'<'), insn, (i?' ':'>'));
155 	}
156 	pr_cont("\n");
157 }
158 
159 static void __show_regs(const struct pt_regs *regs)
160 {
161 	const int field = 2 * sizeof(unsigned long);
162 	unsigned int excsubcode;
163 	unsigned int exccode;
164 	int i;
165 
166 	show_regs_print_info(KERN_DEFAULT);
167 
168 	/*
169 	 * Saved main processor registers
170 	 */
171 	for (i = 0; i < 32; ) {
172 		if ((i % 4) == 0)
173 			printk("$%2d   :", i);
174 		pr_cont(" %0*lx", field, regs->regs[i]);
175 
176 		i++;
177 		if ((i % 4) == 0)
178 			pr_cont("\n");
179 	}
180 
181 	/*
182 	 * Saved csr registers
183 	 */
184 	printk("era   : %0*lx %pS\n", field, regs->csr_era,
185 	       (void *) regs->csr_era);
186 	printk("ra    : %0*lx %pS\n", field, regs->regs[1],
187 	       (void *) regs->regs[1]);
188 
189 	printk("CSR crmd: %08lx	", regs->csr_crmd);
190 	printk("CSR prmd: %08lx	", regs->csr_prmd);
191 	printk("CSR euen: %08lx	", regs->csr_euen);
192 	printk("CSR ecfg: %08lx	", regs->csr_ecfg);
193 	printk("CSR estat: %08lx	", regs->csr_estat);
194 
195 	pr_cont("\n");
196 
197 	exccode = ((regs->csr_estat) & CSR_ESTAT_EXC) >> CSR_ESTAT_EXC_SHIFT;
198 	excsubcode = ((regs->csr_estat) & CSR_ESTAT_ESUBCODE) >> CSR_ESTAT_ESUBCODE_SHIFT;
199 	printk("ExcCode : %x (SubCode %x)\n", exccode, excsubcode);
200 
201 	if (exccode >= EXCCODE_TLBL && exccode <= EXCCODE_ALE)
202 		printk("BadVA : %0*lx\n", field, regs->csr_badvaddr);
203 
204 	printk("PrId  : %08x (%s)\n", read_cpucfg(LOONGARCH_CPUCFG0),
205 	       cpu_family_string());
206 }
207 
208 void show_regs(struct pt_regs *regs)
209 {
210 	__show_regs((struct pt_regs *)regs);
211 	dump_stack();
212 }
213 
214 void show_registers(struct pt_regs *regs)
215 {
216 	__show_regs(regs);
217 	print_modules();
218 	printk("Process %s (pid: %d, threadinfo=%p, task=%p)\n",
219 	       current->comm, current->pid, current_thread_info(), current);
220 
221 	show_stacktrace(current, regs, KERN_DEFAULT, user_mode(regs));
222 	show_code((void *)regs->csr_era, user_mode(regs));
223 	printk("\n");
224 }
225 
226 static DEFINE_RAW_SPINLOCK(die_lock);
227 
228 void __noreturn die(const char *str, struct pt_regs *regs)
229 {
230 	static int die_counter;
231 	int sig = SIGSEGV;
232 
233 	oops_enter();
234 
235 	if (notify_die(DIE_OOPS, str, regs, 0, current->thread.trap_nr,
236 		       SIGSEGV) == NOTIFY_STOP)
237 		sig = 0;
238 
239 	console_verbose();
240 	raw_spin_lock_irq(&die_lock);
241 	bust_spinlocks(1);
242 
243 	printk("%s[#%d]:\n", str, ++die_counter);
244 	show_registers(regs);
245 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
246 	raw_spin_unlock_irq(&die_lock);
247 
248 	oops_exit();
249 
250 	if (regs && kexec_should_crash(current))
251 		crash_kexec(regs);
252 
253 	if (in_interrupt())
254 		panic("Fatal exception in interrupt");
255 
256 	if (panic_on_oops)
257 		panic("Fatal exception");
258 
259 	make_task_dead(sig);
260 }
261 
262 static inline void setup_vint_size(unsigned int size)
263 {
264 	unsigned int vs;
265 
266 	vs = ilog2(size/4);
267 
268 	if (vs == 0 || vs > 7)
269 		panic("vint_size %d Not support yet", vs);
270 
271 	csr_xchg32(vs<<CSR_ECFG_VS_SHIFT, CSR_ECFG_VS, LOONGARCH_CSR_ECFG);
272 }
273 
274 /*
275  * Send SIGFPE according to FCSR Cause bits, which must have already
276  * been masked against Enable bits.  This is impotant as Inexact can
277  * happen together with Overflow or Underflow, and `ptrace' can set
278  * any bits.
279  */
280 void force_fcsr_sig(unsigned long fcsr, void __user *fault_addr,
281 		     struct task_struct *tsk)
282 {
283 	int si_code = FPE_FLTUNK;
284 
285 	if (fcsr & FPU_CSR_INV_X)
286 		si_code = FPE_FLTINV;
287 	else if (fcsr & FPU_CSR_DIV_X)
288 		si_code = FPE_FLTDIV;
289 	else if (fcsr & FPU_CSR_OVF_X)
290 		si_code = FPE_FLTOVF;
291 	else if (fcsr & FPU_CSR_UDF_X)
292 		si_code = FPE_FLTUND;
293 	else if (fcsr & FPU_CSR_INE_X)
294 		si_code = FPE_FLTRES;
295 
296 	force_sig_fault(SIGFPE, si_code, fault_addr);
297 }
298 
299 int process_fpemu_return(int sig, void __user *fault_addr, unsigned long fcsr)
300 {
301 	int si_code;
302 
303 	switch (sig) {
304 	case 0:
305 		return 0;
306 
307 	case SIGFPE:
308 		force_fcsr_sig(fcsr, fault_addr, current);
309 		return 1;
310 
311 	case SIGBUS:
312 		force_sig_fault(SIGBUS, BUS_ADRERR, fault_addr);
313 		return 1;
314 
315 	case SIGSEGV:
316 		mmap_read_lock(current->mm);
317 		if (vma_lookup(current->mm, (unsigned long)fault_addr))
318 			si_code = SEGV_ACCERR;
319 		else
320 			si_code = SEGV_MAPERR;
321 		mmap_read_unlock(current->mm);
322 		force_sig_fault(SIGSEGV, si_code, fault_addr);
323 		return 1;
324 
325 	default:
326 		force_sig(sig);
327 		return 1;
328 	}
329 }
330 
331 /*
332  * Delayed fp exceptions when doing a lazy ctx switch
333  */
334 asmlinkage void noinstr do_fpe(struct pt_regs *regs, unsigned long fcsr)
335 {
336 	int sig;
337 	void __user *fault_addr;
338 	irqentry_state_t state = irqentry_enter(regs);
339 
340 	if (notify_die(DIE_FP, "FP exception", regs, 0, current->thread.trap_nr,
341 		       SIGFPE) == NOTIFY_STOP)
342 		goto out;
343 
344 	/* Clear FCSR.Cause before enabling interrupts */
345 	write_fcsr(LOONGARCH_FCSR0, fcsr & ~mask_fcsr_x(fcsr));
346 	local_irq_enable();
347 
348 	die_if_kernel("FP exception in kernel code", regs);
349 
350 	sig = SIGFPE;
351 	fault_addr = (void __user *) regs->csr_era;
352 
353 	/* Send a signal if required.  */
354 	process_fpemu_return(sig, fault_addr, fcsr);
355 
356 out:
357 	local_irq_disable();
358 	irqentry_exit(regs, state);
359 }
360 
361 asmlinkage void noinstr do_ade(struct pt_regs *regs)
362 {
363 	irqentry_state_t state = irqentry_enter(regs);
364 
365 	die_if_kernel("Kernel ade access", regs);
366 	force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)regs->csr_badvaddr);
367 
368 	irqentry_exit(regs, state);
369 }
370 
371 asmlinkage void noinstr do_ale(struct pt_regs *regs)
372 {
373 	irqentry_state_t state = irqentry_enter(regs);
374 
375 	die_if_kernel("Kernel ale access", regs);
376 	force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)regs->csr_badvaddr);
377 
378 	irqentry_exit(regs, state);
379 }
380 
381 #ifdef CONFIG_GENERIC_BUG
382 int is_valid_bugaddr(unsigned long addr)
383 {
384 	return 1;
385 }
386 #endif /* CONFIG_GENERIC_BUG */
387 
388 static void bug_handler(struct pt_regs *regs)
389 {
390 	switch (report_bug(regs->csr_era, regs)) {
391 	case BUG_TRAP_TYPE_BUG:
392 	case BUG_TRAP_TYPE_NONE:
393 		die_if_kernel("Oops - BUG", regs);
394 		force_sig(SIGTRAP);
395 		break;
396 
397 	case BUG_TRAP_TYPE_WARN:
398 		/* Skip the BUG instruction and continue */
399 		regs->csr_era += LOONGARCH_INSN_SIZE;
400 		break;
401 	}
402 }
403 
404 asmlinkage void noinstr do_bp(struct pt_regs *regs)
405 {
406 	bool user = user_mode(regs);
407 	unsigned int opcode, bcode;
408 	unsigned long era = exception_era(regs);
409 	irqentry_state_t state = irqentry_enter(regs);
410 
411 	local_irq_enable();
412 	current->thread.trap_nr = read_csr_excode();
413 	if (__get_inst(&opcode, (u32 *)era, user))
414 		goto out_sigsegv;
415 
416 	bcode = (opcode & 0x7fff);
417 
418 	/*
419 	 * notify the kprobe handlers, if instruction is likely to
420 	 * pertain to them.
421 	 */
422 	switch (bcode) {
423 	case BRK_KPROBE_BP:
424 		if (notify_die(DIE_BREAK, "Kprobe", regs, bcode,
425 			       current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
426 			goto out;
427 		else
428 			break;
429 	case BRK_KPROBE_SSTEPBP:
430 		if (notify_die(DIE_SSTEPBP, "Kprobe_SingleStep", regs, bcode,
431 			       current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
432 			goto out;
433 		else
434 			break;
435 	case BRK_UPROBE_BP:
436 		if (notify_die(DIE_UPROBE, "Uprobe", regs, bcode,
437 			       current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
438 			goto out;
439 		else
440 			break;
441 	case BRK_UPROBE_XOLBP:
442 		if (notify_die(DIE_UPROBE_XOL, "Uprobe_XOL", regs, bcode,
443 			       current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
444 			goto out;
445 		else
446 			break;
447 	default:
448 		if (notify_die(DIE_TRAP, "Break", regs, bcode,
449 			       current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
450 			goto out;
451 		else
452 			break;
453 	}
454 
455 	switch (bcode) {
456 	case BRK_BUG:
457 		bug_handler(regs);
458 		break;
459 	case BRK_DIVZERO:
460 		die_if_kernel("Break instruction in kernel code", regs);
461 		force_sig_fault(SIGFPE, FPE_INTDIV, (void __user *)regs->csr_era);
462 		break;
463 	case BRK_OVERFLOW:
464 		die_if_kernel("Break instruction in kernel code", regs);
465 		force_sig_fault(SIGFPE, FPE_INTOVF, (void __user *)regs->csr_era);
466 		break;
467 	default:
468 		die_if_kernel("Break instruction in kernel code", regs);
469 		force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->csr_era);
470 		break;
471 	}
472 
473 out:
474 	local_irq_disable();
475 	irqentry_exit(regs, state);
476 	return;
477 
478 out_sigsegv:
479 	force_sig(SIGSEGV);
480 	goto out;
481 }
482 
483 asmlinkage void noinstr do_watch(struct pt_regs *regs)
484 {
485 	pr_warn("Hardware watch point handler not implemented!\n");
486 }
487 
488 asmlinkage void noinstr do_ri(struct pt_regs *regs)
489 {
490 	int status = SIGILL;
491 	unsigned int opcode = 0;
492 	unsigned int __user *era = (unsigned int __user *)exception_era(regs);
493 	irqentry_state_t state = irqentry_enter(regs);
494 
495 	local_irq_enable();
496 	current->thread.trap_nr = read_csr_excode();
497 
498 	if (notify_die(DIE_RI, "RI Fault", regs, 0, current->thread.trap_nr,
499 		       SIGILL) == NOTIFY_STOP)
500 		goto out;
501 
502 	die_if_kernel("Reserved instruction in kernel code", regs);
503 
504 	if (unlikely(get_user(opcode, era) < 0)) {
505 		status = SIGSEGV;
506 		current->thread.error_code = 1;
507 	}
508 
509 	force_sig(status);
510 
511 out:
512 	local_irq_disable();
513 	irqentry_exit(regs, state);
514 }
515 
516 static void init_restore_fp(void)
517 {
518 	if (!used_math()) {
519 		/* First time FP context user. */
520 		init_fpu();
521 	} else {
522 		/* This task has formerly used the FP context */
523 		if (!is_fpu_owner())
524 			own_fpu_inatomic(1);
525 	}
526 
527 	BUG_ON(!is_fp_enabled());
528 }
529 
530 asmlinkage void noinstr do_fpu(struct pt_regs *regs)
531 {
532 	irqentry_state_t state = irqentry_enter(regs);
533 
534 	local_irq_enable();
535 	die_if_kernel("do_fpu invoked from kernel context!", regs);
536 
537 	preempt_disable();
538 	init_restore_fp();
539 	preempt_enable();
540 
541 	local_irq_disable();
542 	irqentry_exit(regs, state);
543 }
544 
545 asmlinkage void noinstr do_lsx(struct pt_regs *regs)
546 {
547 	irqentry_state_t state = irqentry_enter(regs);
548 
549 	local_irq_enable();
550 	force_sig(SIGILL);
551 	local_irq_disable();
552 
553 	irqentry_exit(regs, state);
554 }
555 
556 asmlinkage void noinstr do_lasx(struct pt_regs *regs)
557 {
558 	irqentry_state_t state = irqentry_enter(regs);
559 
560 	local_irq_enable();
561 	force_sig(SIGILL);
562 	local_irq_disable();
563 
564 	irqentry_exit(regs, state);
565 }
566 
567 asmlinkage void noinstr do_lbt(struct pt_regs *regs)
568 {
569 	irqentry_state_t state = irqentry_enter(regs);
570 
571 	local_irq_enable();
572 	force_sig(SIGILL);
573 	local_irq_disable();
574 
575 	irqentry_exit(regs, state);
576 }
577 
578 asmlinkage void noinstr do_reserved(struct pt_regs *regs)
579 {
580 	irqentry_state_t state = irqentry_enter(regs);
581 
582 	local_irq_enable();
583 	/*
584 	 * Game over - no way to handle this if it ever occurs.	Most probably
585 	 * caused by a fatal error after another hardware/software error.
586 	 */
587 	pr_err("Caught reserved exception %u on pid:%d [%s] - should not happen\n",
588 		read_csr_excode(), current->pid, current->comm);
589 	die_if_kernel("do_reserved exception", regs);
590 	force_sig(SIGUNUSED);
591 
592 	local_irq_disable();
593 
594 	irqentry_exit(regs, state);
595 }
596 
597 asmlinkage void cache_parity_error(void)
598 {
599 	/* For the moment, report the problem and hang. */
600 	pr_err("Cache error exception:\n");
601 	pr_err("csr_merrctl == %08x\n", csr_read32(LOONGARCH_CSR_MERRCTL));
602 	pr_err("csr_merrera == %016llx\n", csr_read64(LOONGARCH_CSR_MERRERA));
603 	panic("Can't handle the cache error!");
604 }
605 
606 asmlinkage void noinstr handle_loongarch_irq(struct pt_regs *regs)
607 {
608 	struct pt_regs *old_regs;
609 
610 	irq_enter_rcu();
611 	old_regs = set_irq_regs(regs);
612 	handle_arch_irq(regs);
613 	set_irq_regs(old_regs);
614 	irq_exit_rcu();
615 }
616 
617 asmlinkage void noinstr do_vint(struct pt_regs *regs, unsigned long sp)
618 {
619 	register int cpu;
620 	register unsigned long stack;
621 	irqentry_state_t state = irqentry_enter(regs);
622 
623 	cpu = smp_processor_id();
624 
625 	if (on_irq_stack(cpu, sp))
626 		handle_loongarch_irq(regs);
627 	else {
628 		stack = per_cpu(irq_stack, cpu) + IRQ_STACK_START;
629 
630 		/* Save task's sp on IRQ stack for unwinding */
631 		*(unsigned long *)stack = sp;
632 
633 		__asm__ __volatile__(
634 		"move	$s0, $sp		\n" /* Preserve sp */
635 		"move	$sp, %[stk]		\n" /* Switch stack */
636 		"move	$a0, %[regs]		\n"
637 		"bl	handle_loongarch_irq	\n"
638 		"move	$sp, $s0		\n" /* Restore sp */
639 		: /* No outputs */
640 		: [stk] "r" (stack), [regs] "r" (regs)
641 		: "$a0", "$a1", "$a2", "$a3", "$a4", "$a5", "$a6", "$a7", "$s0",
642 		  "$t0", "$t1", "$t2", "$t3", "$t4", "$t5", "$t6", "$t7", "$t8",
643 		  "memory");
644 	}
645 
646 	irqentry_exit(regs, state);
647 }
648 
649 unsigned long eentry;
650 unsigned long tlbrentry;
651 
652 long exception_handlers[VECSIZE * 128 / sizeof(long)] __aligned(SZ_64K);
653 
654 static void configure_exception_vector(void)
655 {
656 	eentry    = (unsigned long)exception_handlers;
657 	tlbrentry = (unsigned long)exception_handlers + 80*VECSIZE;
658 
659 	csr_write64(eentry, LOONGARCH_CSR_EENTRY);
660 	csr_write64(eentry, LOONGARCH_CSR_MERRENTRY);
661 	csr_write64(tlbrentry, LOONGARCH_CSR_TLBRENTRY);
662 }
663 
664 void per_cpu_trap_init(int cpu)
665 {
666 	unsigned int i;
667 
668 	setup_vint_size(VECSIZE);
669 
670 	configure_exception_vector();
671 
672 	if (!cpu_data[cpu].asid_cache)
673 		cpu_data[cpu].asid_cache = asid_first_version(cpu);
674 
675 	mmgrab(&init_mm);
676 	current->active_mm = &init_mm;
677 	BUG_ON(current->mm);
678 	enter_lazy_tlb(&init_mm, current);
679 
680 	/* Initialise exception handlers */
681 	if (cpu == 0)
682 		for (i = 0; i < 64; i++)
683 			set_handler(i * VECSIZE, handle_reserved, VECSIZE);
684 
685 	tlb_init(cpu);
686 	cpu_cache_init();
687 }
688 
689 /* Install CPU exception handler */
690 void set_handler(unsigned long offset, void *addr, unsigned long size)
691 {
692 	memcpy((void *)(eentry + offset), addr, size);
693 	local_flush_icache_range(eentry + offset, eentry + offset + size);
694 }
695 
696 static const char panic_null_cerr[] =
697 	"Trying to set NULL cache error exception handler\n";
698 
699 /*
700  * Install uncached CPU exception handler.
701  * This is suitable only for the cache error exception which is the only
702  * exception handler that is being run uncached.
703  */
704 void set_merr_handler(unsigned long offset, void *addr, unsigned long size)
705 {
706 	unsigned long uncached_eentry = TO_UNCACHE(__pa(eentry));
707 
708 	if (!addr)
709 		panic(panic_null_cerr);
710 
711 	memcpy((void *)(uncached_eentry + offset), addr, size);
712 }
713 
714 void __init trap_init(void)
715 {
716 	long i;
717 
718 	/* Set interrupt vector handler */
719 	for (i = EXCCODE_INT_START; i < EXCCODE_INT_END; i++)
720 		set_handler(i * VECSIZE, handle_vint, VECSIZE);
721 
722 	set_handler(EXCCODE_ADE * VECSIZE, handle_ade, VECSIZE);
723 	set_handler(EXCCODE_ALE * VECSIZE, handle_ale, VECSIZE);
724 	set_handler(EXCCODE_SYS * VECSIZE, handle_sys, VECSIZE);
725 	set_handler(EXCCODE_BP * VECSIZE, handle_bp, VECSIZE);
726 	set_handler(EXCCODE_INE * VECSIZE, handle_ri, VECSIZE);
727 	set_handler(EXCCODE_IPE * VECSIZE, handle_ri, VECSIZE);
728 	set_handler(EXCCODE_FPDIS * VECSIZE, handle_fpu, VECSIZE);
729 	set_handler(EXCCODE_LSXDIS * VECSIZE, handle_lsx, VECSIZE);
730 	set_handler(EXCCODE_LASXDIS * VECSIZE, handle_lasx, VECSIZE);
731 	set_handler(EXCCODE_FPE * VECSIZE, handle_fpe, VECSIZE);
732 	set_handler(EXCCODE_BTDIS * VECSIZE, handle_lbt, VECSIZE);
733 	set_handler(EXCCODE_WATCH * VECSIZE, handle_watch, VECSIZE);
734 
735 	cache_error_setup();
736 
737 	local_flush_icache_range(eentry, eentry + 0x400);
738 }
739