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1/*
2 * 'traps.c' handles hardware traps and faults after we have saved some
3 * state in 'entry.S'.
4 *
5 * SuperH version: Copyright (C) 1999 Niibe Yutaka
6 * Copyright (C) 2000 Philipp Rumpf
7 * Copyright (C) 2000 David Howells
8 * Copyright (C) 2002 - 2010 Paul Mundt
9 *
10 * This file is subject to the terms and conditions of the GNU General Public
11 * License. See the file "COPYING" in the main directory of this archive
12 * for more details.
13 */
14#include <linux/kernel.h>
15#include <linux/ptrace.h>
16#include <linux/hardirq.h>
17#include <linux/init.h>
18#include <linux/spinlock.h>
19#include <linux/kallsyms.h>
20#include <linux/io.h>
21#include <linux/bug.h>
22#include <linux/debug_locks.h>
23#include <linux/kdebug.h>
24#include <linux/limits.h>
25#include <linux/sysfs.h>
26#include <linux/uaccess.h>
27#include <linux/perf_event.h>
28#include <asm/alignment.h>
29#include <asm/fpu.h>
30#include <asm/kprobes.h>
31#include <asm/traps.h>
32#include <asm/bl_bit.h>
33
34#ifdef CONFIG_CPU_SH2
35# define TRAP_RESERVED_INST 4
36# define TRAP_ILLEGAL_SLOT_INST 6
37# define TRAP_ADDRESS_ERROR 9
38# ifdef CONFIG_CPU_SH2A
39# define TRAP_UBC 12
40# define TRAP_FPU_ERROR 13
41# define TRAP_DIVZERO_ERROR 17
42# define TRAP_DIVOVF_ERROR 18
43# endif
44#else
45#define TRAP_RESERVED_INST 12
46#define TRAP_ILLEGAL_SLOT_INST 13
47#endif
48
49static inline void sign_extend(unsigned int count, unsigned char *dst)
50{
51#ifdef __LITTLE_ENDIAN__
52 if ((count == 1) && dst[0] & 0x80) {
53 dst[1] = 0xff;
54 dst[2] = 0xff;
55 dst[3] = 0xff;
56 }
57 if ((count == 2) && dst[1] & 0x80) {
58 dst[2] = 0xff;
59 dst[3] = 0xff;
60 }
61#else
62 if ((count == 1) && dst[3] & 0x80) {
63 dst[2] = 0xff;
64 dst[1] = 0xff;
65 dst[0] = 0xff;
66 }
67 if ((count == 2) && dst[2] & 0x80) {
68 dst[1] = 0xff;
69 dst[0] = 0xff;
70 }
71#endif
72}
73
74static struct mem_access user_mem_access = {
75 copy_from_user,
76 copy_to_user,
77};
78
79/*
80 * handle an instruction that does an unaligned memory access by emulating the
81 * desired behaviour
82 * - note that PC _may not_ point to the faulting instruction
83 * (if that instruction is in a branch delay slot)
84 * - return 0 if emulation okay, -EFAULT on existential error
85 */
86static int handle_unaligned_ins(insn_size_t instruction, struct pt_regs *regs,
87 struct mem_access *ma)
88{
89 int ret, index, count;
90 unsigned long *rm, *rn;
91 unsigned char *src, *dst;
92 unsigned char __user *srcu, *dstu;
93
94 index = (instruction>>8)&15; /* 0x0F00 */
95 rn = ®s->regs[index];
96
97 index = (instruction>>4)&15; /* 0x00F0 */
98 rm = ®s->regs[index];
99
100 count = 1<<(instruction&3);
101
102 switch (count) {
103 case 1: inc_unaligned_byte_access(); break;
104 case 2: inc_unaligned_word_access(); break;
105 case 4: inc_unaligned_dword_access(); break;
106 case 8: inc_unaligned_multi_access(); break;
107 }
108
109 ret = -EFAULT;
110 switch (instruction>>12) {
111 case 0: /* mov.[bwl] to/from memory via r0+rn */
112 if (instruction & 8) {
113 /* from memory */
114 srcu = (unsigned char __user *)*rm;
115 srcu += regs->regs[0];
116 dst = (unsigned char *)rn;
117 *(unsigned long *)dst = 0;
118
119#if !defined(__LITTLE_ENDIAN__)
120 dst += 4-count;
121#endif
122 if (ma->from(dst, srcu, count))
123 goto fetch_fault;
124
125 sign_extend(count, dst);
126 } else {
127 /* to memory */
128 src = (unsigned char *)rm;
129#if !defined(__LITTLE_ENDIAN__)
130 src += 4-count;
131#endif
132 dstu = (unsigned char __user *)*rn;
133 dstu += regs->regs[0];
134
135 if (ma->to(dstu, src, count))
136 goto fetch_fault;
137 }
138 ret = 0;
139 break;
140
141 case 1: /* mov.l Rm,@(disp,Rn) */
142 src = (unsigned char*) rm;
143 dstu = (unsigned char __user *)*rn;
144 dstu += (instruction&0x000F)<<2;
145
146 if (ma->to(dstu, src, 4))
147 goto fetch_fault;
148 ret = 0;
149 break;
150
151 case 2: /* mov.[bwl] to memory, possibly with pre-decrement */
152 if (instruction & 4)
153 *rn -= count;
154 src = (unsigned char*) rm;
155 dstu = (unsigned char __user *)*rn;
156#if !defined(__LITTLE_ENDIAN__)
157 src += 4-count;
158#endif
159 if (ma->to(dstu, src, count))
160 goto fetch_fault;
161 ret = 0;
162 break;
163
164 case 5: /* mov.l @(disp,Rm),Rn */
165 srcu = (unsigned char __user *)*rm;
166 srcu += (instruction & 0x000F) << 2;
167 dst = (unsigned char *)rn;
168 *(unsigned long *)dst = 0;
169
170 if (ma->from(dst, srcu, 4))
171 goto fetch_fault;
172 ret = 0;
173 break;
174
175 case 6: /* mov.[bwl] from memory, possibly with post-increment */
176 srcu = (unsigned char __user *)*rm;
177 if (instruction & 4)
178 *rm += count;
179 dst = (unsigned char*) rn;
180 *(unsigned long*)dst = 0;
181
182#if !defined(__LITTLE_ENDIAN__)
183 dst += 4-count;
184#endif
185 if (ma->from(dst, srcu, count))
186 goto fetch_fault;
187 sign_extend(count, dst);
188 ret = 0;
189 break;
190
191 case 8:
192 switch ((instruction&0xFF00)>>8) {
193 case 0x81: /* mov.w R0,@(disp,Rn) */
194 src = (unsigned char *) ®s->regs[0];
195#if !defined(__LITTLE_ENDIAN__)
196 src += 2;
197#endif
198 dstu = (unsigned char __user *)*rm; /* called Rn in the spec */
199 dstu += (instruction & 0x000F) << 1;
200
201 if (ma->to(dstu, src, 2))
202 goto fetch_fault;
203 ret = 0;
204 break;
205
206 case 0x85: /* mov.w @(disp,Rm),R0 */
207 srcu = (unsigned char __user *)*rm;
208 srcu += (instruction & 0x000F) << 1;
209 dst = (unsigned char *) ®s->regs[0];
210 *(unsigned long *)dst = 0;
211
212#if !defined(__LITTLE_ENDIAN__)
213 dst += 2;
214#endif
215 if (ma->from(dst, srcu, 2))
216 goto fetch_fault;
217 sign_extend(2, dst);
218 ret = 0;
219 break;
220 }
221 break;
222
223 case 9: /* mov.w @(disp,PC),Rn */
224 srcu = (unsigned char __user *)regs->pc;
225 srcu += 4;
226 srcu += (instruction & 0x00FF) << 1;
227 dst = (unsigned char *)rn;
228 *(unsigned long *)dst = 0;
229
230#if !defined(__LITTLE_ENDIAN__)
231 dst += 2;
232#endif
233
234 if (ma->from(dst, srcu, 2))
235 goto fetch_fault;
236 sign_extend(2, dst);
237 ret = 0;
238 break;
239
240 case 0xd: /* mov.l @(disp,PC),Rn */
241 srcu = (unsigned char __user *)(regs->pc & ~0x3);
242 srcu += 4;
243 srcu += (instruction & 0x00FF) << 2;
244 dst = (unsigned char *)rn;
245 *(unsigned long *)dst = 0;
246
247 if (ma->from(dst, srcu, 4))
248 goto fetch_fault;
249 ret = 0;
250 break;
251 }
252 return ret;
253
254 fetch_fault:
255 /* Argh. Address not only misaligned but also non-existent.
256 * Raise an EFAULT and see if it's trapped
257 */
258 die_if_no_fixup("Fault in unaligned fixup", regs, 0);
259 return -EFAULT;
260}
261
262/*
263 * emulate the instruction in the delay slot
264 * - fetches the instruction from PC+2
265 */
266static inline int handle_delayslot(struct pt_regs *regs,
267 insn_size_t old_instruction,
268 struct mem_access *ma)
269{
270 insn_size_t instruction;
271 void __user *addr = (void __user *)(regs->pc +
272 instruction_size(old_instruction));
273
274 if (copy_from_user(&instruction, addr, sizeof(instruction))) {
275 /* the instruction-fetch faulted */
276 if (user_mode(regs))
277 return -EFAULT;
278
279 /* kernel */
280 die("delay-slot-insn faulting in handle_unaligned_delayslot",
281 regs, 0);
282 }
283
284 return handle_unaligned_ins(instruction, regs, ma);
285}
286
287/*
288 * handle an instruction that does an unaligned memory access
289 * - have to be careful of branch delay-slot instructions that fault
290 * SH3:
291 * - if the branch would be taken PC points to the branch
292 * - if the branch would not be taken, PC points to delay-slot
293 * SH4:
294 * - PC always points to delayed branch
295 * - return 0 if handled, -EFAULT if failed (may not return if in kernel)
296 */
297
298/* Macros to determine offset from current PC for branch instructions */
299/* Explicit type coercion is used to force sign extension where needed */
300#define SH_PC_8BIT_OFFSET(instr) ((((signed char)(instr))*2) + 4)
301#define SH_PC_12BIT_OFFSET(instr) ((((signed short)(instr<<4))>>3) + 4)
302
303int handle_unaligned_access(insn_size_t instruction, struct pt_regs *regs,
304 struct mem_access *ma, int expected,
305 unsigned long address)
306{
307 u_int rm;
308 int ret, index;
309
310 /*
311 * XXX: We can't handle mixed 16/32-bit instructions yet
312 */
313 if (instruction_size(instruction) != 2)
314 return -EINVAL;
315
316 index = (instruction>>8)&15; /* 0x0F00 */
317 rm = regs->regs[index];
318
319 /*
320 * Log the unexpected fixups, and then pass them on to perf.
321 *
322 * We intentionally don't report the expected cases to perf as
323 * otherwise the trapped I/O case will skew the results too much
324 * to be useful.
325 */
326 if (!expected) {
327 unaligned_fixups_notify(current, instruction, regs);
328 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1,
329 regs, address);
330 }
331
332 ret = -EFAULT;
333 switch (instruction&0xF000) {
334 case 0x0000:
335 if (instruction==0x000B) {
336 /* rts */
337 ret = handle_delayslot(regs, instruction, ma);
338 if (ret==0)
339 regs->pc = regs->pr;
340 }
341 else if ((instruction&0x00FF)==0x0023) {
342 /* braf @Rm */
343 ret = handle_delayslot(regs, instruction, ma);
344 if (ret==0)
345 regs->pc += rm + 4;
346 }
347 else if ((instruction&0x00FF)==0x0003) {
348 /* bsrf @Rm */
349 ret = handle_delayslot(regs, instruction, ma);
350 if (ret==0) {
351 regs->pr = regs->pc + 4;
352 regs->pc += rm + 4;
353 }
354 }
355 else {
356 /* mov.[bwl] to/from memory via r0+rn */
357 goto simple;
358 }
359 break;
360
361 case 0x1000: /* mov.l Rm,@(disp,Rn) */
362 goto simple;
363
364 case 0x2000: /* mov.[bwl] to memory, possibly with pre-decrement */
365 goto simple;
366
367 case 0x4000:
368 if ((instruction&0x00FF)==0x002B) {
369 /* jmp @Rm */
370 ret = handle_delayslot(regs, instruction, ma);
371 if (ret==0)
372 regs->pc = rm;
373 }
374 else if ((instruction&0x00FF)==0x000B) {
375 /* jsr @Rm */
376 ret = handle_delayslot(regs, instruction, ma);
377 if (ret==0) {
378 regs->pr = regs->pc + 4;
379 regs->pc = rm;
380 }
381 }
382 else {
383 /* mov.[bwl] to/from memory via r0+rn */
384 goto simple;
385 }
386 break;
387
388 case 0x5000: /* mov.l @(disp,Rm),Rn */
389 goto simple;
390
391 case 0x6000: /* mov.[bwl] from memory, possibly with post-increment */
392 goto simple;
393
394 case 0x8000: /* bf lab, bf/s lab, bt lab, bt/s lab */
395 switch (instruction&0x0F00) {
396 case 0x0100: /* mov.w R0,@(disp,Rm) */
397 goto simple;
398 case 0x0500: /* mov.w @(disp,Rm),R0 */
399 goto simple;
400 case 0x0B00: /* bf lab - no delayslot*/
401 ret = 0;
402 break;
403 case 0x0F00: /* bf/s lab */
404 ret = handle_delayslot(regs, instruction, ma);
405 if (ret==0) {
406#if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
407 if ((regs->sr & 0x00000001) != 0)
408 regs->pc += 4; /* next after slot */
409 else
410#endif
411 regs->pc += SH_PC_8BIT_OFFSET(instruction);
412 }
413 break;
414 case 0x0900: /* bt lab - no delayslot */
415 ret = 0;
416 break;
417 case 0x0D00: /* bt/s lab */
418 ret = handle_delayslot(regs, instruction, ma);
419 if (ret==0) {
420#if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
421 if ((regs->sr & 0x00000001) == 0)
422 regs->pc += 4; /* next after slot */
423 else
424#endif
425 regs->pc += SH_PC_8BIT_OFFSET(instruction);
426 }
427 break;
428 }
429 break;
430
431 case 0x9000: /* mov.w @(disp,Rm),Rn */
432 goto simple;
433
434 case 0xA000: /* bra label */
435 ret = handle_delayslot(regs, instruction, ma);
436 if (ret==0)
437 regs->pc += SH_PC_12BIT_OFFSET(instruction);
438 break;
439
440 case 0xB000: /* bsr label */
441 ret = handle_delayslot(regs, instruction, ma);
442 if (ret==0) {
443 regs->pr = regs->pc + 4;
444 regs->pc += SH_PC_12BIT_OFFSET(instruction);
445 }
446 break;
447
448 case 0xD000: /* mov.l @(disp,Rm),Rn */
449 goto simple;
450 }
451 return ret;
452
453 /* handle non-delay-slot instruction */
454 simple:
455 ret = handle_unaligned_ins(instruction, regs, ma);
456 if (ret==0)
457 regs->pc += instruction_size(instruction);
458 return ret;
459}
460
461/*
462 * Handle various address error exceptions:
463 * - instruction address error:
464 * misaligned PC
465 * PC >= 0x80000000 in user mode
466 * - data address error (read and write)
467 * misaligned data access
468 * access to >= 0x80000000 is user mode
469 * Unfortuntaly we can't distinguish between instruction address error
470 * and data address errors caused by read accesses.
471 */
472asmlinkage void do_address_error(struct pt_regs *regs,
473 unsigned long writeaccess,
474 unsigned long address)
475{
476 unsigned long error_code = 0;
477 mm_segment_t oldfs;
478 siginfo_t info;
479 insn_size_t instruction;
480 int tmp;
481
482 /* Intentional ifdef */
483#ifdef CONFIG_CPU_HAS_SR_RB
484 error_code = lookup_exception_vector();
485#endif
486
487 oldfs = get_fs();
488
489 if (user_mode(regs)) {
490 int si_code = BUS_ADRERR;
491 unsigned int user_action;
492
493 local_irq_enable();
494 inc_unaligned_user_access();
495
496 set_fs(USER_DS);
497 if (copy_from_user(&instruction, (insn_size_t *)(regs->pc & ~1),
498 sizeof(instruction))) {
499 set_fs(oldfs);
500 goto uspace_segv;
501 }
502 set_fs(oldfs);
503
504 /* shout about userspace fixups */
505 unaligned_fixups_notify(current, instruction, regs);
506
507 user_action = unaligned_user_action();
508 if (user_action & UM_FIXUP)
509 goto fixup;
510 if (user_action & UM_SIGNAL)
511 goto uspace_segv;
512 else {
513 /* ignore */
514 regs->pc += instruction_size(instruction);
515 return;
516 }
517
518fixup:
519 /* bad PC is not something we can fix */
520 if (regs->pc & 1) {
521 si_code = BUS_ADRALN;
522 goto uspace_segv;
523 }
524
525 set_fs(USER_DS);
526 tmp = handle_unaligned_access(instruction, regs,
527 &user_mem_access, 0,
528 address);
529 set_fs(oldfs);
530
531 if (tmp == 0)
532 return; /* sorted */
533uspace_segv:
534 printk(KERN_NOTICE "Sending SIGBUS to \"%s\" due to unaligned "
535 "access (PC %lx PR %lx)\n", current->comm, regs->pc,
536 regs->pr);
537
538 info.si_signo = SIGBUS;
539 info.si_errno = 0;
540 info.si_code = si_code;
541 info.si_addr = (void __user *)address;
542 force_sig_info(SIGBUS, &info, current);
543 } else {
544 inc_unaligned_kernel_access();
545
546 if (regs->pc & 1)
547 die("unaligned program counter", regs, error_code);
548
549 set_fs(KERNEL_DS);
550 if (copy_from_user(&instruction, (void __user *)(regs->pc),
551 sizeof(instruction))) {
552 /* Argh. Fault on the instruction itself.
553 This should never happen non-SMP
554 */
555 set_fs(oldfs);
556 die("insn faulting in do_address_error", regs, 0);
557 }
558
559 unaligned_fixups_notify(current, instruction, regs);
560
561 handle_unaligned_access(instruction, regs, &user_mem_access,
562 0, address);
563 set_fs(oldfs);
564 }
565}
566
567#ifdef CONFIG_SH_DSP
568/*
569 * SH-DSP support gerg@snapgear.com.
570 */
571int is_dsp_inst(struct pt_regs *regs)
572{
573 unsigned short inst = 0;
574
575 /*
576 * Safe guard if DSP mode is already enabled or we're lacking
577 * the DSP altogether.
578 */
579 if (!(current_cpu_data.flags & CPU_HAS_DSP) || (regs->sr & SR_DSP))
580 return 0;
581
582 get_user(inst, ((unsigned short *) regs->pc));
583
584 inst &= 0xf000;
585
586 /* Check for any type of DSP or support instruction */
587 if ((inst == 0xf000) || (inst == 0x4000))
588 return 1;
589
590 return 0;
591}
592#else
593#define is_dsp_inst(regs) (0)
594#endif /* CONFIG_SH_DSP */
595
596#ifdef CONFIG_CPU_SH2A
597asmlinkage void do_divide_error(unsigned long r4)
598{
599 siginfo_t info;
600
601 switch (r4) {
602 case TRAP_DIVZERO_ERROR:
603 info.si_code = FPE_INTDIV;
604 break;
605 case TRAP_DIVOVF_ERROR:
606 info.si_code = FPE_INTOVF;
607 break;
608 }
609
610 force_sig_info(SIGFPE, &info, current);
611}
612#endif
613
614asmlinkage void do_reserved_inst(void)
615{
616 struct pt_regs *regs = current_pt_regs();
617 unsigned long error_code;
618 struct task_struct *tsk = current;
619
620#ifdef CONFIG_SH_FPU_EMU
621 unsigned short inst = 0;
622 int err;
623
624 get_user(inst, (unsigned short*)regs->pc);
625
626 err = do_fpu_inst(inst, regs);
627 if (!err) {
628 regs->pc += instruction_size(inst);
629 return;
630 }
631 /* not a FPU inst. */
632#endif
633
634#ifdef CONFIG_SH_DSP
635 /* Check if it's a DSP instruction */
636 if (is_dsp_inst(regs)) {
637 /* Enable DSP mode, and restart instruction. */
638 regs->sr |= SR_DSP;
639 /* Save DSP mode */
640 tsk->thread.dsp_status.status |= SR_DSP;
641 return;
642 }
643#endif
644
645 error_code = lookup_exception_vector();
646
647 local_irq_enable();
648 force_sig(SIGILL, tsk);
649 die_if_no_fixup("reserved instruction", regs, error_code);
650}
651
652#ifdef CONFIG_SH_FPU_EMU
653static int emulate_branch(unsigned short inst, struct pt_regs *regs)
654{
655 /*
656 * bfs: 8fxx: PC+=d*2+4;
657 * bts: 8dxx: PC+=d*2+4;
658 * bra: axxx: PC+=D*2+4;
659 * bsr: bxxx: PC+=D*2+4 after PR=PC+4;
660 * braf:0x23: PC+=Rn*2+4;
661 * bsrf:0x03: PC+=Rn*2+4 after PR=PC+4;
662 * jmp: 4x2b: PC=Rn;
663 * jsr: 4x0b: PC=Rn after PR=PC+4;
664 * rts: 000b: PC=PR;
665 */
666 if (((inst & 0xf000) == 0xb000) || /* bsr */
667 ((inst & 0xf0ff) == 0x0003) || /* bsrf */
668 ((inst & 0xf0ff) == 0x400b)) /* jsr */
669 regs->pr = regs->pc + 4;
670
671 if ((inst & 0xfd00) == 0x8d00) { /* bfs, bts */
672 regs->pc += SH_PC_8BIT_OFFSET(inst);
673 return 0;
674 }
675
676 if ((inst & 0xe000) == 0xa000) { /* bra, bsr */
677 regs->pc += SH_PC_12BIT_OFFSET(inst);
678 return 0;
679 }
680
681 if ((inst & 0xf0df) == 0x0003) { /* braf, bsrf */
682 regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4;
683 return 0;
684 }
685
686 if ((inst & 0xf0df) == 0x400b) { /* jmp, jsr */
687 regs->pc = regs->regs[(inst & 0x0f00) >> 8];
688 return 0;
689 }
690
691 if ((inst & 0xffff) == 0x000b) { /* rts */
692 regs->pc = regs->pr;
693 return 0;
694 }
695
696 return 1;
697}
698#endif
699
700asmlinkage void do_illegal_slot_inst(void)
701{
702 struct pt_regs *regs = current_pt_regs();
703 unsigned long inst;
704 struct task_struct *tsk = current;
705
706 if (kprobe_handle_illslot(regs->pc) == 0)
707 return;
708
709#ifdef CONFIG_SH_FPU_EMU
710 get_user(inst, (unsigned short *)regs->pc + 1);
711 if (!do_fpu_inst(inst, regs)) {
712 get_user(inst, (unsigned short *)regs->pc);
713 if (!emulate_branch(inst, regs))
714 return;
715 /* fault in branch.*/
716 }
717 /* not a FPU inst. */
718#endif
719
720 inst = lookup_exception_vector();
721
722 local_irq_enable();
723 force_sig(SIGILL, tsk);
724 die_if_no_fixup("illegal slot instruction", regs, inst);
725}
726
727asmlinkage void do_exception_error(void)
728{
729 long ex;
730
731 ex = lookup_exception_vector();
732 die_if_kernel("exception", current_pt_regs(), ex);
733}
734
735void per_cpu_trap_init(void)
736{
737 extern void *vbr_base;
738
739 /* NOTE: The VBR value should be at P1
740 (or P2, virtural "fixed" address space).
741 It's definitely should not in physical address. */
742
743 asm volatile("ldc %0, vbr"
744 : /* no output */
745 : "r" (&vbr_base)
746 : "memory");
747
748 /* disable exception blocking now when the vbr has been setup */
749 clear_bl_bit();
750}
751
752void *set_exception_table_vec(unsigned int vec, void *handler)
753{
754 extern void *exception_handling_table[];
755 void *old_handler;
756
757 old_handler = exception_handling_table[vec];
758 exception_handling_table[vec] = handler;
759 return old_handler;
760}
761
762void __init trap_init(void)
763{
764 set_exception_table_vec(TRAP_RESERVED_INST, do_reserved_inst);
765 set_exception_table_vec(TRAP_ILLEGAL_SLOT_INST, do_illegal_slot_inst);
766
767#if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_FPU) || \
768 defined(CONFIG_SH_FPU_EMU)
769 /*
770 * For SH-4 lacking an FPU, treat floating point instructions as
771 * reserved. They'll be handled in the math-emu case, or faulted on
772 * otherwise.
773 */
774 set_exception_table_evt(0x800, do_reserved_inst);
775 set_exception_table_evt(0x820, do_illegal_slot_inst);
776#elif defined(CONFIG_SH_FPU)
777 set_exception_table_evt(0x800, fpu_state_restore_trap_handler);
778 set_exception_table_evt(0x820, fpu_state_restore_trap_handler);
779#endif
780
781#ifdef CONFIG_CPU_SH2
782 set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_trap_handler);
783#endif
784#ifdef CONFIG_CPU_SH2A
785 set_exception_table_vec(TRAP_DIVZERO_ERROR, do_divide_error);
786 set_exception_table_vec(TRAP_DIVOVF_ERROR, do_divide_error);
787#ifdef CONFIG_SH_FPU
788 set_exception_table_vec(TRAP_FPU_ERROR, fpu_error_trap_handler);
789#endif
790#endif
791
792#ifdef TRAP_UBC
793 set_exception_table_vec(TRAP_UBC, breakpoint_trap_handler);
794#endif
795}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * 'traps.c' handles hardware traps and faults after we have saved some
4 * state in 'entry.S'.
5 *
6 * SuperH version: Copyright (C) 1999 Niibe Yutaka
7 * Copyright (C) 2000 Philipp Rumpf
8 * Copyright (C) 2000 David Howells
9 * Copyright (C) 2002 - 2010 Paul Mundt
10 */
11#include <linux/kernel.h>
12#include <linux/ptrace.h>
13#include <linux/hardirq.h>
14#include <linux/init.h>
15#include <linux/spinlock.h>
16#include <linux/kallsyms.h>
17#include <linux/io.h>
18#include <linux/bug.h>
19#include <linux/debug_locks.h>
20#include <linux/kdebug.h>
21#include <linux/limits.h>
22#include <linux/sysfs.h>
23#include <linux/uaccess.h>
24#include <linux/perf_event.h>
25#include <linux/sched/task_stack.h>
26
27#include <asm/alignment.h>
28#include <asm/fpu.h>
29#include <asm/kprobes.h>
30#include <asm/traps.h>
31#include <asm/bl_bit.h>
32
33#ifdef CONFIG_CPU_SH2
34# define TRAP_RESERVED_INST 4
35# define TRAP_ILLEGAL_SLOT_INST 6
36# define TRAP_ADDRESS_ERROR 9
37# ifdef CONFIG_CPU_SH2A
38# define TRAP_UBC 12
39# define TRAP_FPU_ERROR 13
40# define TRAP_DIVZERO_ERROR 17
41# define TRAP_DIVOVF_ERROR 18
42# endif
43#else
44#define TRAP_RESERVED_INST 12
45#define TRAP_ILLEGAL_SLOT_INST 13
46#endif
47
48static inline void sign_extend(unsigned int count, unsigned char *dst)
49{
50#ifdef __LITTLE_ENDIAN__
51 if ((count == 1) && dst[0] & 0x80) {
52 dst[1] = 0xff;
53 dst[2] = 0xff;
54 dst[3] = 0xff;
55 }
56 if ((count == 2) && dst[1] & 0x80) {
57 dst[2] = 0xff;
58 dst[3] = 0xff;
59 }
60#else
61 if ((count == 1) && dst[3] & 0x80) {
62 dst[2] = 0xff;
63 dst[1] = 0xff;
64 dst[0] = 0xff;
65 }
66 if ((count == 2) && dst[2] & 0x80) {
67 dst[1] = 0xff;
68 dst[0] = 0xff;
69 }
70#endif
71}
72
73static struct mem_access user_mem_access = {
74 copy_from_user,
75 copy_to_user,
76};
77
78/*
79 * handle an instruction that does an unaligned memory access by emulating the
80 * desired behaviour
81 * - note that PC _may not_ point to the faulting instruction
82 * (if that instruction is in a branch delay slot)
83 * - return 0 if emulation okay, -EFAULT on existential error
84 */
85static int handle_unaligned_ins(insn_size_t instruction, struct pt_regs *regs,
86 struct mem_access *ma)
87{
88 int ret, index, count;
89 unsigned long *rm, *rn;
90 unsigned char *src, *dst;
91 unsigned char __user *srcu, *dstu;
92
93 index = (instruction>>8)&15; /* 0x0F00 */
94 rn = ®s->regs[index];
95
96 index = (instruction>>4)&15; /* 0x00F0 */
97 rm = ®s->regs[index];
98
99 count = 1<<(instruction&3);
100
101 switch (count) {
102 case 1: inc_unaligned_byte_access(); break;
103 case 2: inc_unaligned_word_access(); break;
104 case 4: inc_unaligned_dword_access(); break;
105 case 8: inc_unaligned_multi_access(); break;
106 }
107
108 ret = -EFAULT;
109 switch (instruction>>12) {
110 case 0: /* mov.[bwl] to/from memory via r0+rn */
111 if (instruction & 8) {
112 /* from memory */
113 srcu = (unsigned char __user *)*rm;
114 srcu += regs->regs[0];
115 dst = (unsigned char *)rn;
116 *(unsigned long *)dst = 0;
117
118#if !defined(__LITTLE_ENDIAN__)
119 dst += 4-count;
120#endif
121 if (ma->from(dst, srcu, count))
122 goto fetch_fault;
123
124 sign_extend(count, dst);
125 } else {
126 /* to memory */
127 src = (unsigned char *)rm;
128#if !defined(__LITTLE_ENDIAN__)
129 src += 4-count;
130#endif
131 dstu = (unsigned char __user *)*rn;
132 dstu += regs->regs[0];
133
134 if (ma->to(dstu, src, count))
135 goto fetch_fault;
136 }
137 ret = 0;
138 break;
139
140 case 1: /* mov.l Rm,@(disp,Rn) */
141 src = (unsigned char*) rm;
142 dstu = (unsigned char __user *)*rn;
143 dstu += (instruction&0x000F)<<2;
144
145 if (ma->to(dstu, src, 4))
146 goto fetch_fault;
147 ret = 0;
148 break;
149
150 case 2: /* mov.[bwl] to memory, possibly with pre-decrement */
151 if (instruction & 4)
152 *rn -= count;
153 src = (unsigned char*) rm;
154 dstu = (unsigned char __user *)*rn;
155#if !defined(__LITTLE_ENDIAN__)
156 src += 4-count;
157#endif
158 if (ma->to(dstu, src, count))
159 goto fetch_fault;
160 ret = 0;
161 break;
162
163 case 5: /* mov.l @(disp,Rm),Rn */
164 srcu = (unsigned char __user *)*rm;
165 srcu += (instruction & 0x000F) << 2;
166 dst = (unsigned char *)rn;
167 *(unsigned long *)dst = 0;
168
169 if (ma->from(dst, srcu, 4))
170 goto fetch_fault;
171 ret = 0;
172 break;
173
174 case 6: /* mov.[bwl] from memory, possibly with post-increment */
175 srcu = (unsigned char __user *)*rm;
176 if (instruction & 4)
177 *rm += count;
178 dst = (unsigned char*) rn;
179 *(unsigned long*)dst = 0;
180
181#if !defined(__LITTLE_ENDIAN__)
182 dst += 4-count;
183#endif
184 if (ma->from(dst, srcu, count))
185 goto fetch_fault;
186 sign_extend(count, dst);
187 ret = 0;
188 break;
189
190 case 8:
191 switch ((instruction&0xFF00)>>8) {
192 case 0x81: /* mov.w R0,@(disp,Rn) */
193 src = (unsigned char *) ®s->regs[0];
194#if !defined(__LITTLE_ENDIAN__)
195 src += 2;
196#endif
197 dstu = (unsigned char __user *)*rm; /* called Rn in the spec */
198 dstu += (instruction & 0x000F) << 1;
199
200 if (ma->to(dstu, src, 2))
201 goto fetch_fault;
202 ret = 0;
203 break;
204
205 case 0x85: /* mov.w @(disp,Rm),R0 */
206 srcu = (unsigned char __user *)*rm;
207 srcu += (instruction & 0x000F) << 1;
208 dst = (unsigned char *) ®s->regs[0];
209 *(unsigned long *)dst = 0;
210
211#if !defined(__LITTLE_ENDIAN__)
212 dst += 2;
213#endif
214 if (ma->from(dst, srcu, 2))
215 goto fetch_fault;
216 sign_extend(2, dst);
217 ret = 0;
218 break;
219 }
220 break;
221
222 case 9: /* mov.w @(disp,PC),Rn */
223 srcu = (unsigned char __user *)regs->pc;
224 srcu += 4;
225 srcu += (instruction & 0x00FF) << 1;
226 dst = (unsigned char *)rn;
227 *(unsigned long *)dst = 0;
228
229#if !defined(__LITTLE_ENDIAN__)
230 dst += 2;
231#endif
232
233 if (ma->from(dst, srcu, 2))
234 goto fetch_fault;
235 sign_extend(2, dst);
236 ret = 0;
237 break;
238
239 case 0xd: /* mov.l @(disp,PC),Rn */
240 srcu = (unsigned char __user *)(regs->pc & ~0x3);
241 srcu += 4;
242 srcu += (instruction & 0x00FF) << 2;
243 dst = (unsigned char *)rn;
244 *(unsigned long *)dst = 0;
245
246 if (ma->from(dst, srcu, 4))
247 goto fetch_fault;
248 ret = 0;
249 break;
250 }
251 return ret;
252
253 fetch_fault:
254 /* Argh. Address not only misaligned but also non-existent.
255 * Raise an EFAULT and see if it's trapped
256 */
257 die_if_no_fixup("Fault in unaligned fixup", regs, 0);
258 return -EFAULT;
259}
260
261/*
262 * emulate the instruction in the delay slot
263 * - fetches the instruction from PC+2
264 */
265static inline int handle_delayslot(struct pt_regs *regs,
266 insn_size_t old_instruction,
267 struct mem_access *ma)
268{
269 insn_size_t instruction;
270 void __user *addr = (void __user *)(regs->pc +
271 instruction_size(old_instruction));
272
273 if (copy_from_user(&instruction, addr, sizeof(instruction))) {
274 /* the instruction-fetch faulted */
275 if (user_mode(regs))
276 return -EFAULT;
277
278 /* kernel */
279 die("delay-slot-insn faulting in handle_unaligned_delayslot",
280 regs, 0);
281 }
282
283 return handle_unaligned_ins(instruction, regs, ma);
284}
285
286/*
287 * handle an instruction that does an unaligned memory access
288 * - have to be careful of branch delay-slot instructions that fault
289 * SH3:
290 * - if the branch would be taken PC points to the branch
291 * - if the branch would not be taken, PC points to delay-slot
292 * SH4:
293 * - PC always points to delayed branch
294 * - return 0 if handled, -EFAULT if failed (may not return if in kernel)
295 */
296
297/* Macros to determine offset from current PC for branch instructions */
298/* Explicit type coercion is used to force sign extension where needed */
299#define SH_PC_8BIT_OFFSET(instr) ((((signed char)(instr))*2) + 4)
300#define SH_PC_12BIT_OFFSET(instr) ((((signed short)(instr<<4))>>3) + 4)
301
302int handle_unaligned_access(insn_size_t instruction, struct pt_regs *regs,
303 struct mem_access *ma, int expected,
304 unsigned long address)
305{
306 u_int rm;
307 int ret, index;
308
309 /*
310 * XXX: We can't handle mixed 16/32-bit instructions yet
311 */
312 if (instruction_size(instruction) != 2)
313 return -EINVAL;
314
315 index = (instruction>>8)&15; /* 0x0F00 */
316 rm = regs->regs[index];
317
318 /*
319 * Log the unexpected fixups, and then pass them on to perf.
320 *
321 * We intentionally don't report the expected cases to perf as
322 * otherwise the trapped I/O case will skew the results too much
323 * to be useful.
324 */
325 if (!expected) {
326 unaligned_fixups_notify(current, instruction, regs);
327 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1,
328 regs, address);
329 }
330
331 ret = -EFAULT;
332 switch (instruction&0xF000) {
333 case 0x0000:
334 if (instruction==0x000B) {
335 /* rts */
336 ret = handle_delayslot(regs, instruction, ma);
337 if (ret==0)
338 regs->pc = regs->pr;
339 }
340 else if ((instruction&0x00FF)==0x0023) {
341 /* braf @Rm */
342 ret = handle_delayslot(regs, instruction, ma);
343 if (ret==0)
344 regs->pc += rm + 4;
345 }
346 else if ((instruction&0x00FF)==0x0003) {
347 /* bsrf @Rm */
348 ret = handle_delayslot(regs, instruction, ma);
349 if (ret==0) {
350 regs->pr = regs->pc + 4;
351 regs->pc += rm + 4;
352 }
353 }
354 else {
355 /* mov.[bwl] to/from memory via r0+rn */
356 goto simple;
357 }
358 break;
359
360 case 0x1000: /* mov.l Rm,@(disp,Rn) */
361 goto simple;
362
363 case 0x2000: /* mov.[bwl] to memory, possibly with pre-decrement */
364 goto simple;
365
366 case 0x4000:
367 if ((instruction&0x00FF)==0x002B) {
368 /* jmp @Rm */
369 ret = handle_delayslot(regs, instruction, ma);
370 if (ret==0)
371 regs->pc = rm;
372 }
373 else if ((instruction&0x00FF)==0x000B) {
374 /* jsr @Rm */
375 ret = handle_delayslot(regs, instruction, ma);
376 if (ret==0) {
377 regs->pr = regs->pc + 4;
378 regs->pc = rm;
379 }
380 }
381 else {
382 /* mov.[bwl] to/from memory via r0+rn */
383 goto simple;
384 }
385 break;
386
387 case 0x5000: /* mov.l @(disp,Rm),Rn */
388 goto simple;
389
390 case 0x6000: /* mov.[bwl] from memory, possibly with post-increment */
391 goto simple;
392
393 case 0x8000: /* bf lab, bf/s lab, bt lab, bt/s lab */
394 switch (instruction&0x0F00) {
395 case 0x0100: /* mov.w R0,@(disp,Rm) */
396 goto simple;
397 case 0x0500: /* mov.w @(disp,Rm),R0 */
398 goto simple;
399 case 0x0B00: /* bf lab - no delayslot*/
400 ret = 0;
401 break;
402 case 0x0F00: /* bf/s lab */
403 ret = handle_delayslot(regs, instruction, ma);
404 if (ret==0) {
405#if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
406 if ((regs->sr & 0x00000001) != 0)
407 regs->pc += 4; /* next after slot */
408 else
409#endif
410 regs->pc += SH_PC_8BIT_OFFSET(instruction);
411 }
412 break;
413 case 0x0900: /* bt lab - no delayslot */
414 ret = 0;
415 break;
416 case 0x0D00: /* bt/s lab */
417 ret = handle_delayslot(regs, instruction, ma);
418 if (ret==0) {
419#if defined(CONFIG_CPU_SH4) || defined(CONFIG_SH7705_CACHE_32KB)
420 if ((regs->sr & 0x00000001) == 0)
421 regs->pc += 4; /* next after slot */
422 else
423#endif
424 regs->pc += SH_PC_8BIT_OFFSET(instruction);
425 }
426 break;
427 }
428 break;
429
430 case 0x9000: /* mov.w @(disp,Rm),Rn */
431 goto simple;
432
433 case 0xA000: /* bra label */
434 ret = handle_delayslot(regs, instruction, ma);
435 if (ret==0)
436 regs->pc += SH_PC_12BIT_OFFSET(instruction);
437 break;
438
439 case 0xB000: /* bsr label */
440 ret = handle_delayslot(regs, instruction, ma);
441 if (ret==0) {
442 regs->pr = regs->pc + 4;
443 regs->pc += SH_PC_12BIT_OFFSET(instruction);
444 }
445 break;
446
447 case 0xD000: /* mov.l @(disp,Rm),Rn */
448 goto simple;
449 }
450 return ret;
451
452 /* handle non-delay-slot instruction */
453 simple:
454 ret = handle_unaligned_ins(instruction, regs, ma);
455 if (ret==0)
456 regs->pc += instruction_size(instruction);
457 return ret;
458}
459
460/*
461 * Handle various address error exceptions:
462 * - instruction address error:
463 * misaligned PC
464 * PC >= 0x80000000 in user mode
465 * - data address error (read and write)
466 * misaligned data access
467 * access to >= 0x80000000 is user mode
468 * Unfortuntaly we can't distinguish between instruction address error
469 * and data address errors caused by read accesses.
470 */
471asmlinkage void do_address_error(struct pt_regs *regs,
472 unsigned long writeaccess,
473 unsigned long address)
474{
475 unsigned long error_code = 0;
476 mm_segment_t oldfs;
477 insn_size_t instruction;
478 int tmp;
479
480 /* Intentional ifdef */
481#ifdef CONFIG_CPU_HAS_SR_RB
482 error_code = lookup_exception_vector();
483#endif
484
485 oldfs = get_fs();
486
487 if (user_mode(regs)) {
488 int si_code = BUS_ADRERR;
489 unsigned int user_action;
490
491 local_irq_enable();
492 inc_unaligned_user_access();
493
494 set_fs(USER_DS);
495 if (copy_from_user(&instruction, (insn_size_t *)(regs->pc & ~1),
496 sizeof(instruction))) {
497 set_fs(oldfs);
498 goto uspace_segv;
499 }
500 set_fs(oldfs);
501
502 /* shout about userspace fixups */
503 unaligned_fixups_notify(current, instruction, regs);
504
505 user_action = unaligned_user_action();
506 if (user_action & UM_FIXUP)
507 goto fixup;
508 if (user_action & UM_SIGNAL)
509 goto uspace_segv;
510 else {
511 /* ignore */
512 regs->pc += instruction_size(instruction);
513 return;
514 }
515
516fixup:
517 /* bad PC is not something we can fix */
518 if (regs->pc & 1) {
519 si_code = BUS_ADRALN;
520 goto uspace_segv;
521 }
522
523 set_fs(USER_DS);
524 tmp = handle_unaligned_access(instruction, regs,
525 &user_mem_access, 0,
526 address);
527 set_fs(oldfs);
528
529 if (tmp == 0)
530 return; /* sorted */
531uspace_segv:
532 printk(KERN_NOTICE "Sending SIGBUS to \"%s\" due to unaligned "
533 "access (PC %lx PR %lx)\n", current->comm, regs->pc,
534 regs->pr);
535
536 force_sig_fault(SIGBUS, si_code, (void __user *)address);
537 } else {
538 inc_unaligned_kernel_access();
539
540 if (regs->pc & 1)
541 die("unaligned program counter", regs, error_code);
542
543 set_fs(KERNEL_DS);
544 if (copy_from_user(&instruction, (void __user *)(regs->pc),
545 sizeof(instruction))) {
546 /* Argh. Fault on the instruction itself.
547 This should never happen non-SMP
548 */
549 set_fs(oldfs);
550 die("insn faulting in do_address_error", regs, 0);
551 }
552
553 unaligned_fixups_notify(current, instruction, regs);
554
555 handle_unaligned_access(instruction, regs, &user_mem_access,
556 0, address);
557 set_fs(oldfs);
558 }
559}
560
561#ifdef CONFIG_SH_DSP
562/*
563 * SH-DSP support gerg@snapgear.com.
564 */
565int is_dsp_inst(struct pt_regs *regs)
566{
567 unsigned short inst = 0;
568
569 /*
570 * Safe guard if DSP mode is already enabled or we're lacking
571 * the DSP altogether.
572 */
573 if (!(current_cpu_data.flags & CPU_HAS_DSP) || (regs->sr & SR_DSP))
574 return 0;
575
576 get_user(inst, ((unsigned short *) regs->pc));
577
578 inst &= 0xf000;
579
580 /* Check for any type of DSP or support instruction */
581 if ((inst == 0xf000) || (inst == 0x4000))
582 return 1;
583
584 return 0;
585}
586#else
587#define is_dsp_inst(regs) (0)
588#endif /* CONFIG_SH_DSP */
589
590#ifdef CONFIG_CPU_SH2A
591asmlinkage void do_divide_error(unsigned long r4)
592{
593 int code;
594
595 switch (r4) {
596 case TRAP_DIVZERO_ERROR:
597 code = FPE_INTDIV;
598 break;
599 case TRAP_DIVOVF_ERROR:
600 code = FPE_INTOVF;
601 break;
602 default:
603 /* Let gcc know unhandled cases don't make it past here */
604 return;
605 }
606 force_sig_fault(SIGFPE, code, NULL);
607}
608#endif
609
610asmlinkage void do_reserved_inst(void)
611{
612 struct pt_regs *regs = current_pt_regs();
613 unsigned long error_code;
614
615#ifdef CONFIG_SH_FPU_EMU
616 unsigned short inst = 0;
617 int err;
618
619 get_user(inst, (unsigned short*)regs->pc);
620
621 err = do_fpu_inst(inst, regs);
622 if (!err) {
623 regs->pc += instruction_size(inst);
624 return;
625 }
626 /* not a FPU inst. */
627#endif
628
629#ifdef CONFIG_SH_DSP
630 /* Check if it's a DSP instruction */
631 if (is_dsp_inst(regs)) {
632 /* Enable DSP mode, and restart instruction. */
633 regs->sr |= SR_DSP;
634 /* Save DSP mode */
635 current->thread.dsp_status.status |= SR_DSP;
636 return;
637 }
638#endif
639
640 error_code = lookup_exception_vector();
641
642 local_irq_enable();
643 force_sig(SIGILL);
644 die_if_no_fixup("reserved instruction", regs, error_code);
645}
646
647#ifdef CONFIG_SH_FPU_EMU
648static int emulate_branch(unsigned short inst, struct pt_regs *regs)
649{
650 /*
651 * bfs: 8fxx: PC+=d*2+4;
652 * bts: 8dxx: PC+=d*2+4;
653 * bra: axxx: PC+=D*2+4;
654 * bsr: bxxx: PC+=D*2+4 after PR=PC+4;
655 * braf:0x23: PC+=Rn*2+4;
656 * bsrf:0x03: PC+=Rn*2+4 after PR=PC+4;
657 * jmp: 4x2b: PC=Rn;
658 * jsr: 4x0b: PC=Rn after PR=PC+4;
659 * rts: 000b: PC=PR;
660 */
661 if (((inst & 0xf000) == 0xb000) || /* bsr */
662 ((inst & 0xf0ff) == 0x0003) || /* bsrf */
663 ((inst & 0xf0ff) == 0x400b)) /* jsr */
664 regs->pr = regs->pc + 4;
665
666 if ((inst & 0xfd00) == 0x8d00) { /* bfs, bts */
667 regs->pc += SH_PC_8BIT_OFFSET(inst);
668 return 0;
669 }
670
671 if ((inst & 0xe000) == 0xa000) { /* bra, bsr */
672 regs->pc += SH_PC_12BIT_OFFSET(inst);
673 return 0;
674 }
675
676 if ((inst & 0xf0df) == 0x0003) { /* braf, bsrf */
677 regs->pc += regs->regs[(inst & 0x0f00) >> 8] + 4;
678 return 0;
679 }
680
681 if ((inst & 0xf0df) == 0x400b) { /* jmp, jsr */
682 regs->pc = regs->regs[(inst & 0x0f00) >> 8];
683 return 0;
684 }
685
686 if ((inst & 0xffff) == 0x000b) { /* rts */
687 regs->pc = regs->pr;
688 return 0;
689 }
690
691 return 1;
692}
693#endif
694
695asmlinkage void do_illegal_slot_inst(void)
696{
697 struct pt_regs *regs = current_pt_regs();
698 unsigned long inst;
699
700 if (kprobe_handle_illslot(regs->pc) == 0)
701 return;
702
703#ifdef CONFIG_SH_FPU_EMU
704 get_user(inst, (unsigned short *)regs->pc + 1);
705 if (!do_fpu_inst(inst, regs)) {
706 get_user(inst, (unsigned short *)regs->pc);
707 if (!emulate_branch(inst, regs))
708 return;
709 /* fault in branch.*/
710 }
711 /* not a FPU inst. */
712#endif
713
714 inst = lookup_exception_vector();
715
716 local_irq_enable();
717 force_sig(SIGILL);
718 die_if_no_fixup("illegal slot instruction", regs, inst);
719}
720
721asmlinkage void do_exception_error(void)
722{
723 long ex;
724
725 ex = lookup_exception_vector();
726 die_if_kernel("exception", current_pt_regs(), ex);
727}
728
729void per_cpu_trap_init(void)
730{
731 extern void *vbr_base;
732
733 /* NOTE: The VBR value should be at P1
734 (or P2, virtural "fixed" address space).
735 It's definitely should not in physical address. */
736
737 asm volatile("ldc %0, vbr"
738 : /* no output */
739 : "r" (&vbr_base)
740 : "memory");
741
742 /* disable exception blocking now when the vbr has been setup */
743 clear_bl_bit();
744}
745
746void *set_exception_table_vec(unsigned int vec, void *handler)
747{
748 extern void *exception_handling_table[];
749 void *old_handler;
750
751 old_handler = exception_handling_table[vec];
752 exception_handling_table[vec] = handler;
753 return old_handler;
754}
755
756void __init trap_init(void)
757{
758 set_exception_table_vec(TRAP_RESERVED_INST, do_reserved_inst);
759 set_exception_table_vec(TRAP_ILLEGAL_SLOT_INST, do_illegal_slot_inst);
760
761#if defined(CONFIG_CPU_SH4) && !defined(CONFIG_SH_FPU) || \
762 defined(CONFIG_SH_FPU_EMU)
763 /*
764 * For SH-4 lacking an FPU, treat floating point instructions as
765 * reserved. They'll be handled in the math-emu case, or faulted on
766 * otherwise.
767 */
768 set_exception_table_evt(0x800, do_reserved_inst);
769 set_exception_table_evt(0x820, do_illegal_slot_inst);
770#elif defined(CONFIG_SH_FPU)
771 set_exception_table_evt(0x800, fpu_state_restore_trap_handler);
772 set_exception_table_evt(0x820, fpu_state_restore_trap_handler);
773#endif
774
775#ifdef CONFIG_CPU_SH2
776 set_exception_table_vec(TRAP_ADDRESS_ERROR, address_error_trap_handler);
777#endif
778#ifdef CONFIG_CPU_SH2A
779 set_exception_table_vec(TRAP_DIVZERO_ERROR, do_divide_error);
780 set_exception_table_vec(TRAP_DIVOVF_ERROR, do_divide_error);
781#ifdef CONFIG_SH_FPU
782 set_exception_table_vec(TRAP_FPU_ERROR, fpu_error_trap_handler);
783#endif
784#endif
785
786#ifdef TRAP_UBC
787 set_exception_table_vec(TRAP_UBC, breakpoint_trap_handler);
788#endif
789}