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