xref: /openbmc/linux/arch/loongarch/kernel/traps.c (revision 5e0266f0)
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 	printk("%sCall Trace:", loglvl);
76 	for (unwind_start(&state, task, pregs);
77 	      !unwind_done(&state); unwind_next_frame(&state)) {
78 		addr = unwind_get_return_address(&state);
79 		print_ip_sym(loglvl, addr);
80 	}
81 	printk("%s\n", loglvl);
82 }
83 
84 static void show_stacktrace(struct task_struct *task,
85 	const struct pt_regs *regs, const char *loglvl, bool user)
86 {
87 	int i;
88 	const int field = 2 * sizeof(unsigned long);
89 	unsigned long stackdata;
90 	unsigned long *sp = (unsigned long *)regs->regs[3];
91 
92 	printk("%sStack :", loglvl);
93 	i = 0;
94 	while ((unsigned long) sp & (PAGE_SIZE - 1)) {
95 		if (i && ((i % (64 / field)) == 0)) {
96 			pr_cont("\n");
97 			printk("%s       ", loglvl);
98 		}
99 		if (i > 39) {
100 			pr_cont(" ...");
101 			break;
102 		}
103 
104 		if (__get_addr(&stackdata, sp++, user)) {
105 			pr_cont(" (Bad stack address)");
106 			break;
107 		}
108 
109 		pr_cont(" %0*lx", field, stackdata);
110 		i++;
111 	}
112 	pr_cont("\n");
113 	show_backtrace(task, regs, loglvl, user);
114 }
115 
116 void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
117 {
118 	struct pt_regs regs;
119 
120 	regs.csr_crmd = 0;
121 	if (sp) {
122 		regs.csr_era = 0;
123 		regs.regs[1] = 0;
124 		regs.regs[3] = (unsigned long)sp;
125 	} else {
126 		if (!task || task == current)
127 			prepare_frametrace(&regs);
128 		else {
129 			regs.csr_era = task->thread.reg01;
130 			regs.regs[1] = 0;
131 			regs.regs[3] = task->thread.reg03;
132 			regs.regs[22] = task->thread.reg22;
133 		}
134 	}
135 
136 	show_stacktrace(task, &regs, loglvl, false);
137 }
138 
139 static void show_code(unsigned int *pc, bool user)
140 {
141 	long i;
142 	unsigned int insn;
143 
144 	printk("Code:");
145 
146 	for(i = -3 ; i < 6 ; i++) {
147 		if (__get_inst(&insn, pc + i, user)) {
148 			pr_cont(" (Bad address in era)\n");
149 			break;
150 		}
151 		pr_cont("%c%08x%c", (i?' ':'<'), insn, (i?' ':'>'));
152 	}
153 	pr_cont("\n");
154 }
155 
156 static void __show_regs(const struct pt_regs *regs)
157 {
158 	const int field = 2 * sizeof(unsigned long);
159 	unsigned int excsubcode;
160 	unsigned int exccode;
161 	int i;
162 
163 	show_regs_print_info(KERN_DEFAULT);
164 
165 	/*
166 	 * Saved main processor registers
167 	 */
168 	for (i = 0; i < 32; ) {
169 		if ((i % 4) == 0)
170 			printk("$%2d   :", i);
171 		pr_cont(" %0*lx", field, regs->regs[i]);
172 
173 		i++;
174 		if ((i % 4) == 0)
175 			pr_cont("\n");
176 	}
177 
178 	/*
179 	 * Saved csr registers
180 	 */
181 	printk("era   : %0*lx %pS\n", field, regs->csr_era,
182 	       (void *) regs->csr_era);
183 	printk("ra    : %0*lx %pS\n", field, regs->regs[1],
184 	       (void *) regs->regs[1]);
185 
186 	printk("CSR crmd: %08lx	", regs->csr_crmd);
187 	printk("CSR prmd: %08lx	", regs->csr_prmd);
188 	printk("CSR euen: %08lx	", regs->csr_euen);
189 	printk("CSR ecfg: %08lx	", regs->csr_ecfg);
190 	printk("CSR estat: %08lx	", regs->csr_estat);
191 
192 	pr_cont("\n");
193 
194 	exccode = ((regs->csr_estat) & CSR_ESTAT_EXC) >> CSR_ESTAT_EXC_SHIFT;
195 	excsubcode = ((regs->csr_estat) & CSR_ESTAT_ESUBCODE) >> CSR_ESTAT_ESUBCODE_SHIFT;
196 	printk("ExcCode : %x (SubCode %x)\n", exccode, excsubcode);
197 
198 	if (exccode >= EXCCODE_TLBL && exccode <= EXCCODE_ALE)
199 		printk("BadVA : %0*lx\n", field, regs->csr_badvaddr);
200 
201 	printk("PrId  : %08x (%s)\n", read_cpucfg(LOONGARCH_CPUCFG0),
202 	       cpu_family_string());
203 }
204 
205 void show_regs(struct pt_regs *regs)
206 {
207 	__show_regs((struct pt_regs *)regs);
208 	dump_stack();
209 }
210 
211 void show_registers(struct pt_regs *regs)
212 {
213 	__show_regs(regs);
214 	print_modules();
215 	printk("Process %s (pid: %d, threadinfo=%p, task=%p)\n",
216 	       current->comm, current->pid, current_thread_info(), current);
217 
218 	show_stacktrace(current, regs, KERN_DEFAULT, user_mode(regs));
219 	show_code((void *)regs->csr_era, user_mode(regs));
220 	printk("\n");
221 }
222 
223 static DEFINE_RAW_SPINLOCK(die_lock);
224 
225 void __noreturn die(const char *str, struct pt_regs *regs)
226 {
227 	static int die_counter;
228 	int sig = SIGSEGV;
229 
230 	oops_enter();
231 
232 	if (notify_die(DIE_OOPS, str, regs, 0, current->thread.trap_nr,
233 		       SIGSEGV) == NOTIFY_STOP)
234 		sig = 0;
235 
236 	console_verbose();
237 	raw_spin_lock_irq(&die_lock);
238 	bust_spinlocks(1);
239 
240 	printk("%s[#%d]:\n", str, ++die_counter);
241 	show_registers(regs);
242 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
243 	raw_spin_unlock_irq(&die_lock);
244 
245 	oops_exit();
246 
247 	if (regs && kexec_should_crash(current))
248 		crash_kexec(regs);
249 
250 	if (in_interrupt())
251 		panic("Fatal exception in interrupt");
252 
253 	if (panic_on_oops)
254 		panic("Fatal exception");
255 
256 	make_task_dead(sig);
257 }
258 
259 static inline void setup_vint_size(unsigned int size)
260 {
261 	unsigned int vs;
262 
263 	vs = ilog2(size/4);
264 
265 	if (vs == 0 || vs > 7)
266 		panic("vint_size %d Not support yet", vs);
267 
268 	csr_xchg32(vs<<CSR_ECFG_VS_SHIFT, CSR_ECFG_VS, LOONGARCH_CSR_ECFG);
269 }
270 
271 /*
272  * Send SIGFPE according to FCSR Cause bits, which must have already
273  * been masked against Enable bits.  This is impotant as Inexact can
274  * happen together with Overflow or Underflow, and `ptrace' can set
275  * any bits.
276  */
277 void force_fcsr_sig(unsigned long fcsr, void __user *fault_addr,
278 		     struct task_struct *tsk)
279 {
280 	int si_code = FPE_FLTUNK;
281 
282 	if (fcsr & FPU_CSR_INV_X)
283 		si_code = FPE_FLTINV;
284 	else if (fcsr & FPU_CSR_DIV_X)
285 		si_code = FPE_FLTDIV;
286 	else if (fcsr & FPU_CSR_OVF_X)
287 		si_code = FPE_FLTOVF;
288 	else if (fcsr & FPU_CSR_UDF_X)
289 		si_code = FPE_FLTUND;
290 	else if (fcsr & FPU_CSR_INE_X)
291 		si_code = FPE_FLTRES;
292 
293 	force_sig_fault(SIGFPE, si_code, fault_addr);
294 }
295 
296 int process_fpemu_return(int sig, void __user *fault_addr, unsigned long fcsr)
297 {
298 	int si_code;
299 
300 	switch (sig) {
301 	case 0:
302 		return 0;
303 
304 	case SIGFPE:
305 		force_fcsr_sig(fcsr, fault_addr, current);
306 		return 1;
307 
308 	case SIGBUS:
309 		force_sig_fault(SIGBUS, BUS_ADRERR, fault_addr);
310 		return 1;
311 
312 	case SIGSEGV:
313 		mmap_read_lock(current->mm);
314 		if (vma_lookup(current->mm, (unsigned long)fault_addr))
315 			si_code = SEGV_ACCERR;
316 		else
317 			si_code = SEGV_MAPERR;
318 		mmap_read_unlock(current->mm);
319 		force_sig_fault(SIGSEGV, si_code, fault_addr);
320 		return 1;
321 
322 	default:
323 		force_sig(sig);
324 		return 1;
325 	}
326 }
327 
328 /*
329  * Delayed fp exceptions when doing a lazy ctx switch
330  */
331 asmlinkage void noinstr do_fpe(struct pt_regs *regs, unsigned long fcsr)
332 {
333 	int sig;
334 	void __user *fault_addr;
335 	irqentry_state_t state = irqentry_enter(regs);
336 
337 	if (notify_die(DIE_FP, "FP exception", regs, 0, current->thread.trap_nr,
338 		       SIGFPE) == NOTIFY_STOP)
339 		goto out;
340 
341 	/* Clear FCSR.Cause before enabling interrupts */
342 	write_fcsr(LOONGARCH_FCSR0, fcsr & ~mask_fcsr_x(fcsr));
343 	local_irq_enable();
344 
345 	die_if_kernel("FP exception in kernel code", regs);
346 
347 	sig = SIGFPE;
348 	fault_addr = (void __user *) regs->csr_era;
349 
350 	/* Send a signal if required.  */
351 	process_fpemu_return(sig, fault_addr, fcsr);
352 
353 out:
354 	local_irq_disable();
355 	irqentry_exit(regs, state);
356 }
357 
358 asmlinkage void noinstr do_ade(struct pt_regs *regs)
359 {
360 	irqentry_state_t state = irqentry_enter(regs);
361 
362 	die_if_kernel("Kernel ade access", regs);
363 	force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)regs->csr_badvaddr);
364 
365 	irqentry_exit(regs, state);
366 }
367 
368 /* sysctl hooks */
369 int unaligned_enabled __read_mostly = 1;	/* Enabled by default */
370 int no_unaligned_warning __read_mostly = 1;	/* Only 1 warning by default */
371 
372 asmlinkage void noinstr do_ale(struct pt_regs *regs)
373 {
374 	irqentry_state_t state = irqentry_enter(regs);
375 
376 #ifndef CONFIG_ARCH_STRICT_ALIGN
377 	die_if_kernel("Kernel ale access", regs);
378 	force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)regs->csr_badvaddr);
379 #else
380 	unsigned int *pc;
381 
382 	perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, regs->csr_badvaddr);
383 
384 	/*
385 	 * Did we catch a fault trying to load an instruction?
386 	 */
387 	if (regs->csr_badvaddr == regs->csr_era)
388 		goto sigbus;
389 	if (user_mode(regs) && !test_thread_flag(TIF_FIXADE))
390 		goto sigbus;
391 	if (!unaligned_enabled)
392 		goto sigbus;
393 	if (!no_unaligned_warning)
394 		show_registers(regs);
395 
396 	pc = (unsigned int *)exception_era(regs);
397 
398 	emulate_load_store_insn(regs, (void __user *)regs->csr_badvaddr, pc);
399 
400 	goto out;
401 
402 sigbus:
403 	die_if_kernel("Kernel ale access", regs);
404 	force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)regs->csr_badvaddr);
405 out:
406 #endif
407 	irqentry_exit(regs, state);
408 }
409 
410 #ifdef CONFIG_GENERIC_BUG
411 int is_valid_bugaddr(unsigned long addr)
412 {
413 	return 1;
414 }
415 #endif /* CONFIG_GENERIC_BUG */
416 
417 static void bug_handler(struct pt_regs *regs)
418 {
419 	switch (report_bug(regs->csr_era, regs)) {
420 	case BUG_TRAP_TYPE_BUG:
421 	case BUG_TRAP_TYPE_NONE:
422 		die_if_kernel("Oops - BUG", regs);
423 		force_sig(SIGTRAP);
424 		break;
425 
426 	case BUG_TRAP_TYPE_WARN:
427 		/* Skip the BUG instruction and continue */
428 		regs->csr_era += LOONGARCH_INSN_SIZE;
429 		break;
430 	}
431 }
432 
433 asmlinkage void noinstr do_bp(struct pt_regs *regs)
434 {
435 	bool user = user_mode(regs);
436 	unsigned int opcode, bcode;
437 	unsigned long era = exception_era(regs);
438 	irqentry_state_t state = irqentry_enter(regs);
439 
440 	if (regs->csr_prmd & CSR_PRMD_PIE)
441 		local_irq_enable();
442 
443 	current->thread.trap_nr = read_csr_excode();
444 	if (__get_inst(&opcode, (u32 *)era, user))
445 		goto out_sigsegv;
446 
447 	bcode = (opcode & 0x7fff);
448 
449 	/*
450 	 * notify the kprobe handlers, if instruction is likely to
451 	 * pertain to them.
452 	 */
453 	switch (bcode) {
454 	case BRK_KPROBE_BP:
455 		if (kprobe_breakpoint_handler(regs))
456 			goto out;
457 		else
458 			break;
459 	case BRK_KPROBE_SSTEPBP:
460 		if (kprobe_singlestep_handler(regs))
461 			goto out;
462 		else
463 			break;
464 	case BRK_UPROBE_BP:
465 		if (notify_die(DIE_UPROBE, "Uprobe", regs, bcode,
466 			       current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
467 			goto out;
468 		else
469 			break;
470 	case BRK_UPROBE_XOLBP:
471 		if (notify_die(DIE_UPROBE_XOL, "Uprobe_XOL", regs, bcode,
472 			       current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
473 			goto out;
474 		else
475 			break;
476 	default:
477 		if (notify_die(DIE_TRAP, "Break", regs, bcode,
478 			       current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
479 			goto out;
480 		else
481 			break;
482 	}
483 
484 	switch (bcode) {
485 	case BRK_BUG:
486 		bug_handler(regs);
487 		break;
488 	case BRK_DIVZERO:
489 		die_if_kernel("Break instruction in kernel code", regs);
490 		force_sig_fault(SIGFPE, FPE_INTDIV, (void __user *)regs->csr_era);
491 		break;
492 	case BRK_OVERFLOW:
493 		die_if_kernel("Break instruction in kernel code", regs);
494 		force_sig_fault(SIGFPE, FPE_INTOVF, (void __user *)regs->csr_era);
495 		break;
496 	default:
497 		die_if_kernel("Break instruction in kernel code", regs);
498 		force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->csr_era);
499 		break;
500 	}
501 
502 out:
503 	if (regs->csr_prmd & CSR_PRMD_PIE)
504 		local_irq_disable();
505 
506 	irqentry_exit(regs, state);
507 	return;
508 
509 out_sigsegv:
510 	force_sig(SIGSEGV);
511 	goto out;
512 }
513 
514 asmlinkage void noinstr do_watch(struct pt_regs *regs)
515 {
516 	irqentry_state_t state = irqentry_enter(regs);
517 
518 #ifndef CONFIG_HAVE_HW_BREAKPOINT
519 	pr_warn("Hardware watch point handler not implemented!\n");
520 #else
521 	if (test_tsk_thread_flag(current, TIF_SINGLESTEP)) {
522 		int llbit = (csr_read32(LOONGARCH_CSR_LLBCTL) & 0x1);
523 		unsigned long pc = instruction_pointer(regs);
524 		union loongarch_instruction *ip = (union loongarch_instruction *)pc;
525 
526 		if (llbit) {
527 			/*
528 			 * When the ll-sc combo is encountered, it is regarded as an single
529 			 * instruction. So don't clear llbit and reset CSR.FWPS.Skip until
530 			 * the llsc execution is completed.
531 			 */
532 			csr_write32(CSR_FWPC_SKIP, LOONGARCH_CSR_FWPS);
533 			csr_write32(CSR_LLBCTL_KLO, LOONGARCH_CSR_LLBCTL);
534 			goto out;
535 		}
536 
537 		if (pc == current->thread.single_step) {
538 			/*
539 			 * Certain insns are occasionally not skipped when CSR.FWPS.Skip is
540 			 * set, such as fld.d/fst.d. So singlestep needs to compare whether
541 			 * the csr_era is equal to the value of singlestep which last time set.
542 			 */
543 			if (!is_self_loop_ins(ip, regs)) {
544 				/*
545 				 * Check if the given instruction the target pc is equal to the
546 				 * current pc, If yes, then we should not set the CSR.FWPS.SKIP
547 				 * bit to break the original instruction stream.
548 				 */
549 				csr_write32(CSR_FWPC_SKIP, LOONGARCH_CSR_FWPS);
550 				goto out;
551 			}
552 		}
553 	} else {
554 		breakpoint_handler(regs);
555 		watchpoint_handler(regs);
556 	}
557 
558 	force_sig(SIGTRAP);
559 out:
560 #endif
561 	irqentry_exit(regs, state);
562 }
563 
564 asmlinkage void noinstr do_ri(struct pt_regs *regs)
565 {
566 	int status = SIGILL;
567 	unsigned int opcode = 0;
568 	unsigned int __user *era = (unsigned int __user *)exception_era(regs);
569 	irqentry_state_t state = irqentry_enter(regs);
570 
571 	local_irq_enable();
572 	current->thread.trap_nr = read_csr_excode();
573 
574 	if (notify_die(DIE_RI, "RI Fault", regs, 0, current->thread.trap_nr,
575 		       SIGILL) == NOTIFY_STOP)
576 		goto out;
577 
578 	die_if_kernel("Reserved instruction in kernel code", regs);
579 
580 	if (unlikely(get_user(opcode, era) < 0)) {
581 		status = SIGSEGV;
582 		current->thread.error_code = 1;
583 	}
584 
585 	force_sig(status);
586 
587 out:
588 	local_irq_disable();
589 	irqentry_exit(regs, state);
590 }
591 
592 static void init_restore_fp(void)
593 {
594 	if (!used_math()) {
595 		/* First time FP context user. */
596 		init_fpu();
597 	} else {
598 		/* This task has formerly used the FP context */
599 		if (!is_fpu_owner())
600 			own_fpu_inatomic(1);
601 	}
602 
603 	BUG_ON(!is_fp_enabled());
604 }
605 
606 asmlinkage void noinstr do_fpu(struct pt_regs *regs)
607 {
608 	irqentry_state_t state = irqentry_enter(regs);
609 
610 	local_irq_enable();
611 	die_if_kernel("do_fpu invoked from kernel context!", regs);
612 
613 	preempt_disable();
614 	init_restore_fp();
615 	preempt_enable();
616 
617 	local_irq_disable();
618 	irqentry_exit(regs, state);
619 }
620 
621 asmlinkage void noinstr do_lsx(struct pt_regs *regs)
622 {
623 	irqentry_state_t state = irqentry_enter(regs);
624 
625 	local_irq_enable();
626 	force_sig(SIGILL);
627 	local_irq_disable();
628 
629 	irqentry_exit(regs, state);
630 }
631 
632 asmlinkage void noinstr do_lasx(struct pt_regs *regs)
633 {
634 	irqentry_state_t state = irqentry_enter(regs);
635 
636 	local_irq_enable();
637 	force_sig(SIGILL);
638 	local_irq_disable();
639 
640 	irqentry_exit(regs, state);
641 }
642 
643 asmlinkage void noinstr do_lbt(struct pt_regs *regs)
644 {
645 	irqentry_state_t state = irqentry_enter(regs);
646 
647 	local_irq_enable();
648 	force_sig(SIGILL);
649 	local_irq_disable();
650 
651 	irqentry_exit(regs, state);
652 }
653 
654 asmlinkage void noinstr do_reserved(struct pt_regs *regs)
655 {
656 	irqentry_state_t state = irqentry_enter(regs);
657 
658 	local_irq_enable();
659 	/*
660 	 * Game over - no way to handle this if it ever occurs.	Most probably
661 	 * caused by a fatal error after another hardware/software error.
662 	 */
663 	pr_err("Caught reserved exception %u on pid:%d [%s] - should not happen\n",
664 		read_csr_excode(), current->pid, current->comm);
665 	die_if_kernel("do_reserved exception", regs);
666 	force_sig(SIGUNUSED);
667 
668 	local_irq_disable();
669 
670 	irqentry_exit(regs, state);
671 }
672 
673 asmlinkage void cache_parity_error(void)
674 {
675 	/* For the moment, report the problem and hang. */
676 	pr_err("Cache error exception:\n");
677 	pr_err("csr_merrctl == %08x\n", csr_read32(LOONGARCH_CSR_MERRCTL));
678 	pr_err("csr_merrera == %016llx\n", csr_read64(LOONGARCH_CSR_MERRERA));
679 	panic("Can't handle the cache error!");
680 }
681 
682 asmlinkage void noinstr handle_loongarch_irq(struct pt_regs *regs)
683 {
684 	struct pt_regs *old_regs;
685 
686 	irq_enter_rcu();
687 	old_regs = set_irq_regs(regs);
688 	handle_arch_irq(regs);
689 	set_irq_regs(old_regs);
690 	irq_exit_rcu();
691 }
692 
693 asmlinkage void noinstr do_vint(struct pt_regs *regs, unsigned long sp)
694 {
695 	register int cpu;
696 	register unsigned long stack;
697 	irqentry_state_t state = irqentry_enter(regs);
698 
699 	cpu = smp_processor_id();
700 
701 	if (on_irq_stack(cpu, sp))
702 		handle_loongarch_irq(regs);
703 	else {
704 		stack = per_cpu(irq_stack, cpu) + IRQ_STACK_START;
705 
706 		/* Save task's sp on IRQ stack for unwinding */
707 		*(unsigned long *)stack = sp;
708 
709 		__asm__ __volatile__(
710 		"move	$s0, $sp		\n" /* Preserve sp */
711 		"move	$sp, %[stk]		\n" /* Switch stack */
712 		"move	$a0, %[regs]		\n"
713 		"bl	handle_loongarch_irq	\n"
714 		"move	$sp, $s0		\n" /* Restore sp */
715 		: /* No outputs */
716 		: [stk] "r" (stack), [regs] "r" (regs)
717 		: "$a0", "$a1", "$a2", "$a3", "$a4", "$a5", "$a6", "$a7", "$s0",
718 		  "$t0", "$t1", "$t2", "$t3", "$t4", "$t5", "$t6", "$t7", "$t8",
719 		  "memory");
720 	}
721 
722 	irqentry_exit(regs, state);
723 }
724 
725 unsigned long eentry;
726 unsigned long tlbrentry;
727 
728 long exception_handlers[VECSIZE * 128 / sizeof(long)] __aligned(SZ_64K);
729 
730 static void configure_exception_vector(void)
731 {
732 	eentry    = (unsigned long)exception_handlers;
733 	tlbrentry = (unsigned long)exception_handlers + 80*VECSIZE;
734 
735 	csr_write64(eentry, LOONGARCH_CSR_EENTRY);
736 	csr_write64(eentry, LOONGARCH_CSR_MERRENTRY);
737 	csr_write64(tlbrentry, LOONGARCH_CSR_TLBRENTRY);
738 }
739 
740 void per_cpu_trap_init(int cpu)
741 {
742 	unsigned int i;
743 
744 	setup_vint_size(VECSIZE);
745 
746 	configure_exception_vector();
747 
748 	if (!cpu_data[cpu].asid_cache)
749 		cpu_data[cpu].asid_cache = asid_first_version(cpu);
750 
751 	mmgrab(&init_mm);
752 	current->active_mm = &init_mm;
753 	BUG_ON(current->mm);
754 	enter_lazy_tlb(&init_mm, current);
755 
756 	/* Initialise exception handlers */
757 	if (cpu == 0)
758 		for (i = 0; i < 64; i++)
759 			set_handler(i * VECSIZE, handle_reserved, VECSIZE);
760 
761 	tlb_init(cpu);
762 	cpu_cache_init();
763 }
764 
765 /* Install CPU exception handler */
766 void set_handler(unsigned long offset, void *addr, unsigned long size)
767 {
768 	memcpy((void *)(eentry + offset), addr, size);
769 	local_flush_icache_range(eentry + offset, eentry + offset + size);
770 }
771 
772 static const char panic_null_cerr[] =
773 	"Trying to set NULL cache error exception handler\n";
774 
775 /*
776  * Install uncached CPU exception handler.
777  * This is suitable only for the cache error exception which is the only
778  * exception handler that is being run uncached.
779  */
780 void set_merr_handler(unsigned long offset, void *addr, unsigned long size)
781 {
782 	unsigned long uncached_eentry = TO_UNCACHE(__pa(eentry));
783 
784 	if (!addr)
785 		panic(panic_null_cerr);
786 
787 	memcpy((void *)(uncached_eentry + offset), addr, size);
788 }
789 
790 void __init trap_init(void)
791 {
792 	long i;
793 
794 	/* Set interrupt vector handler */
795 	for (i = EXCCODE_INT_START; i < EXCCODE_INT_END; i++)
796 		set_handler(i * VECSIZE, handle_vint, VECSIZE);
797 
798 	set_handler(EXCCODE_ADE * VECSIZE, handle_ade, VECSIZE);
799 	set_handler(EXCCODE_ALE * VECSIZE, handle_ale, VECSIZE);
800 	set_handler(EXCCODE_SYS * VECSIZE, handle_sys, VECSIZE);
801 	set_handler(EXCCODE_BP * VECSIZE, handle_bp, VECSIZE);
802 	set_handler(EXCCODE_INE * VECSIZE, handle_ri, VECSIZE);
803 	set_handler(EXCCODE_IPE * VECSIZE, handle_ri, VECSIZE);
804 	set_handler(EXCCODE_FPDIS * VECSIZE, handle_fpu, VECSIZE);
805 	set_handler(EXCCODE_LSXDIS * VECSIZE, handle_lsx, VECSIZE);
806 	set_handler(EXCCODE_LASXDIS * VECSIZE, handle_lasx, VECSIZE);
807 	set_handler(EXCCODE_FPE * VECSIZE, handle_fpe, VECSIZE);
808 	set_handler(EXCCODE_BTDIS * VECSIZE, handle_lbt, VECSIZE);
809 	set_handler(EXCCODE_WATCH * VECSIZE, handle_watch, VECSIZE);
810 
811 	cache_error_setup();
812 
813 	local_flush_icache_range(eentry, eentry + 0x400);
814 }
815