1/* 2 * Exception handling for Microblaze 3 * 4 * Rewriten interrupt handling 5 * 6 * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu> 7 * Copyright (C) 2008-2009 PetaLogix 8 * 9 * uClinux customisation (C) 2005 John Williams 10 * 11 * MMU code derived from arch/ppc/kernel/head_4xx.S: 12 * Copyright (C) 1995-1996 Gary Thomas <gdt@linuxppc.org> 13 * Initial PowerPC version. 14 * Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu> 15 * Rewritten for PReP 16 * Copyright (C) 1996 Paul Mackerras <paulus@cs.anu.edu.au> 17 * Low-level exception handers, MMU support, and rewrite. 18 * Copyright (C) 1997 Dan Malek <dmalek@jlc.net> 19 * PowerPC 8xx modifications. 20 * Copyright (C) 1998-1999 TiVo, Inc. 21 * PowerPC 403GCX modifications. 22 * Copyright (C) 1999 Grant Erickson <grant@lcse.umn.edu> 23 * PowerPC 403GCX/405GP modifications. 24 * Copyright 2000 MontaVista Software Inc. 25 * PPC405 modifications 26 * PowerPC 403GCX/405GP modifications. 27 * Author: MontaVista Software, Inc. 28 * frank_rowand@mvista.com or source@mvista.com 29 * debbie_chu@mvista.com 30 * 31 * Original code 32 * Copyright (C) 2004 Xilinx, Inc. 33 * 34 * This program is free software; you can redistribute it and/or modify it 35 * under the terms of the GNU General Public License version 2 as published 36 * by the Free Software Foundation. 37 */ 38 39/* 40 * Here are the handlers which don't require enabling translation 41 * and calling other kernel code thus we can keep their design very simple 42 * and do all processing in real mode. All what they need is a valid current 43 * (that is an issue for the CONFIG_REGISTER_TASK_PTR case) 44 * This handlers use r3,r4,r5,r6 and optionally r[current] to work therefore 45 * these registers are saved/restored 46 * The handlers which require translation are in entry.S --KAA 47 * 48 * Microblaze HW Exception Handler 49 * - Non self-modifying exception handler for the following exception conditions 50 * - Unalignment 51 * - Instruction bus error 52 * - Data bus error 53 * - Illegal instruction opcode 54 * - Divide-by-zero 55 * 56 * - Privileged instruction exception (MMU) 57 * - Data storage exception (MMU) 58 * - Instruction storage exception (MMU) 59 * - Data TLB miss exception (MMU) 60 * - Instruction TLB miss exception (MMU) 61 * 62 * Note we disable interrupts during exception handling, otherwise we will 63 * possibly get multiple re-entrancy if interrupt handles themselves cause 64 * exceptions. JW 65 */ 66 67#include <asm/exceptions.h> 68#include <asm/unistd.h> 69#include <asm/page.h> 70 71#include <asm/entry.h> 72#include <asm/current.h> 73#include <linux/linkage.h> 74 75#include <asm/mmu.h> 76#include <asm/pgtable.h> 77#include <asm/signal.h> 78#include <asm/asm-offsets.h> 79 80/* Helpful Macros */ 81#ifndef CONFIG_MMU 82#define EX_HANDLER_STACK_SIZ (4*19) 83#endif 84#define NUM_TO_REG(num) r ## num 85 86#ifdef CONFIG_MMU 87 #define RESTORE_STATE \ 88 lwi r5, r1, 0; \ 89 mts rmsr, r5; \ 90 nop; \ 91 lwi r3, r1, PT_R3; \ 92 lwi r4, r1, PT_R4; \ 93 lwi r5, r1, PT_R5; \ 94 lwi r6, r1, PT_R6; \ 95 lwi r11, r1, PT_R11; \ 96 lwi r31, r1, PT_R31; \ 97 lwi r1, r0, TOPHYS(r0_ram + 0); 98#endif /* CONFIG_MMU */ 99 100#define LWREG_NOP \ 101 bri ex_handler_unhandled; \ 102 nop; 103 104#define SWREG_NOP \ 105 bri ex_handler_unhandled; \ 106 nop; 107 108/* FIXME this is weird - for noMMU kernel is not possible to use brid 109 * instruction which can shorten executed time 110 */ 111 112/* r3 is the source */ 113#define R3_TO_LWREG_V(regnum) \ 114 swi r3, r1, 4 * regnum; \ 115 bri ex_handler_done; 116 117/* r3 is the source */ 118#define R3_TO_LWREG(regnum) \ 119 or NUM_TO_REG (regnum), r0, r3; \ 120 bri ex_handler_done; 121 122/* r3 is the target */ 123#define SWREG_TO_R3_V(regnum) \ 124 lwi r3, r1, 4 * regnum; \ 125 bri ex_sw_tail; 126 127/* r3 is the target */ 128#define SWREG_TO_R3(regnum) \ 129 or r3, r0, NUM_TO_REG (regnum); \ 130 bri ex_sw_tail; 131 132#ifdef CONFIG_MMU 133 #define R3_TO_LWREG_VM_V(regnum) \ 134 brid ex_lw_end_vm; \ 135 swi r3, r7, 4 * regnum; 136 137 #define R3_TO_LWREG_VM(regnum) \ 138 brid ex_lw_end_vm; \ 139 or NUM_TO_REG (regnum), r0, r3; 140 141 #define SWREG_TO_R3_VM_V(regnum) \ 142 brid ex_sw_tail_vm; \ 143 lwi r3, r7, 4 * regnum; 144 145 #define SWREG_TO_R3_VM(regnum) \ 146 brid ex_sw_tail_vm; \ 147 or r3, r0, NUM_TO_REG (regnum); 148 149 /* Shift right instruction depending on available configuration */ 150 #if CONFIG_XILINX_MICROBLAZE0_USE_BARREL > 0 151 #define BSRLI(rD, rA, imm) \ 152 bsrli rD, rA, imm 153 #elif CONFIG_XILINX_MICROBLAZE0_USE_DIV > 0 154 #define BSRLI(rD, rA, imm) \ 155 ori rD, r0, (1 << imm); \ 156 idivu rD, rD, rA 157 #else 158 #define BSRLI(rD, rA, imm) BSRLI ## imm (rD, rA) 159 /* Only the used shift constants defined here - add more if needed */ 160 #define BSRLI2(rD, rA) \ 161 srl rD, rA; /* << 1 */ \ 162 srl rD, rD; /* << 2 */ 163 #define BSRLI10(rD, rA) \ 164 srl rD, rA; /* << 1 */ \ 165 srl rD, rD; /* << 2 */ \ 166 srl rD, rD; /* << 3 */ \ 167 srl rD, rD; /* << 4 */ \ 168 srl rD, rD; /* << 5 */ \ 169 srl rD, rD; /* << 6 */ \ 170 srl rD, rD; /* << 7 */ \ 171 srl rD, rD; /* << 8 */ \ 172 srl rD, rD; /* << 9 */ \ 173 srl rD, rD /* << 10 */ 174 #define BSRLI20(rD, rA) \ 175 BSRLI10(rD, rA); \ 176 BSRLI10(rD, rD) 177 #endif 178#endif /* CONFIG_MMU */ 179 180.extern other_exception_handler /* Defined in exception.c */ 181 182/* 183 * hw_exception_handler - Handler for exceptions 184 * 185 * Exception handler notes: 186 * - Handles all exceptions 187 * - Does not handle unaligned exceptions during load into r17, r1, r0. 188 * - Does not handle unaligned exceptions during store from r17 (cannot be 189 * done) and r1 (slows down common case) 190 * 191 * Relevant register structures 192 * 193 * EAR - |----|----|----|----|----|----|----|----| 194 * - < ## 32 bit faulting address ## > 195 * 196 * ESR - |----|----|----|----|----| - | - |-----|-----| 197 * - W S REG EXC 198 * 199 * 200 * STACK FRAME STRUCTURE (for NO_MMU) 201 * --------------------------------- 202 * 203 * +-------------+ + 0 204 * | MSR | 205 * +-------------+ + 4 206 * | r1 | 207 * | . | 208 * | . | 209 * | . | 210 * | . | 211 * | r18 | 212 * +-------------+ + 76 213 * | . | 214 * | . | 215 * 216 * NO_MMU kernel use the same r0_ram pointed space - look to vmlinux.lds.S 217 * which is used for storing register values - old style was, that value were 218 * stored in stack but in case of failure you lost information about register. 219 * Currently you can see register value in memory in specific place. 220 * In compare to with previous solution the speed should be the same. 221 * 222 * MMU exception handler has different handling compare to no MMU kernel. 223 * Exception handler use jump table for directing of what happen. For MMU kernel 224 * is this approach better because MMU relate exception are handled by asm code 225 * in this file. In compare to with MMU expect of unaligned exception 226 * is everything handled by C code. 227 */ 228 229/* 230 * every of these handlers is entered having R3/4/5/6/11/current saved on stack 231 * and clobbered so care should be taken to restore them if someone is going to 232 * return from exception 233 */ 234 235/* wrappers to restore state before coming to entry.S */ 236 237#ifdef CONFIG_MMU 238.section .rodata 239.align 4 240_MB_HW_ExceptionVectorTable: 241/* 0 - Undefined */ 242 .long TOPHYS(ex_handler_unhandled) 243/* 1 - Unaligned data access exception */ 244 .long TOPHYS(handle_unaligned_ex) 245/* 2 - Illegal op-code exception */ 246 .long TOPHYS(full_exception_trapw) 247/* 3 - Instruction bus error exception */ 248 .long TOPHYS(full_exception_trapw) 249/* 4 - Data bus error exception */ 250 .long TOPHYS(full_exception_trapw) 251/* 5 - Divide by zero exception */ 252 .long TOPHYS(full_exception_trapw) 253/* 6 - Floating point unit exception */ 254 .long TOPHYS(full_exception_trapw) 255/* 7 - Privileged instruction exception */ 256 .long TOPHYS(full_exception_trapw) 257/* 8 - 15 - Undefined */ 258 .long TOPHYS(ex_handler_unhandled) 259 .long TOPHYS(ex_handler_unhandled) 260 .long TOPHYS(ex_handler_unhandled) 261 .long TOPHYS(ex_handler_unhandled) 262 .long TOPHYS(ex_handler_unhandled) 263 .long TOPHYS(ex_handler_unhandled) 264 .long TOPHYS(ex_handler_unhandled) 265 .long TOPHYS(ex_handler_unhandled) 266/* 16 - Data storage exception */ 267 .long TOPHYS(handle_data_storage_exception) 268/* 17 - Instruction storage exception */ 269 .long TOPHYS(handle_instruction_storage_exception) 270/* 18 - Data TLB miss exception */ 271 .long TOPHYS(handle_data_tlb_miss_exception) 272/* 19 - Instruction TLB miss exception */ 273 .long TOPHYS(handle_instruction_tlb_miss_exception) 274/* 20 - 31 - Undefined */ 275 .long TOPHYS(ex_handler_unhandled) 276 .long TOPHYS(ex_handler_unhandled) 277 .long TOPHYS(ex_handler_unhandled) 278 .long TOPHYS(ex_handler_unhandled) 279 .long TOPHYS(ex_handler_unhandled) 280 .long TOPHYS(ex_handler_unhandled) 281 .long TOPHYS(ex_handler_unhandled) 282 .long TOPHYS(ex_handler_unhandled) 283 .long TOPHYS(ex_handler_unhandled) 284 .long TOPHYS(ex_handler_unhandled) 285 .long TOPHYS(ex_handler_unhandled) 286 .long TOPHYS(ex_handler_unhandled) 287#endif 288 289.global _hw_exception_handler 290.section .text 291.align 4 292.ent _hw_exception_handler 293_hw_exception_handler: 294#ifndef CONFIG_MMU 295 addik r1, r1, -(EX_HANDLER_STACK_SIZ); /* Create stack frame */ 296#else 297 swi r1, r0, TOPHYS(r0_ram + 0); /* GET_SP */ 298 /* Save date to kernel memory. Here is the problem 299 * when you came from user space */ 300 ori r1, r0, TOPHYS(r0_ram + 28); 301#endif 302 swi r3, r1, PT_R3 303 swi r4, r1, PT_R4 304 swi r5, r1, PT_R5 305 swi r6, r1, PT_R6 306 307#ifdef CONFIG_MMU 308 swi r11, r1, PT_R11 309 swi r31, r1, PT_R31 310 lwi r31, r0, TOPHYS(PER_CPU(CURRENT_SAVE)) /* get saved current */ 311#endif 312 313 mfs r5, rmsr; 314 nop 315 swi r5, r1, 0; 316 mfs r4, resr 317 nop 318 mfs r3, rear; 319 nop 320 321#ifndef CONFIG_MMU 322 andi r5, r4, 0x1000; /* Check ESR[DS] */ 323 beqi r5, not_in_delay_slot; /* Branch if ESR[DS] not set */ 324 mfs r17, rbtr; /* ESR[DS] set - return address in BTR */ 325 nop 326not_in_delay_slot: 327 swi r17, r1, PT_R17 328#endif 329 330 andi r5, r4, 0x1F; /* Extract ESR[EXC] */ 331 332#ifdef CONFIG_MMU 333 /* Calculate exception vector offset = r5 << 2 */ 334 addk r6, r5, r5; /* << 1 */ 335 addk r6, r6, r6; /* << 2 */ 336 337#ifdef DEBUG 338/* counting which exception happen */ 339 lwi r5, r0, 0x200 + TOPHYS(r0_ram) 340 addi r5, r5, 1 341 swi r5, r0, 0x200 + TOPHYS(r0_ram) 342 lwi r5, r6, 0x200 + TOPHYS(r0_ram) 343 addi r5, r5, 1 344 swi r5, r6, 0x200 + TOPHYS(r0_ram) 345#endif 346/* end */ 347 /* Load the HW Exception vector */ 348 lwi r6, r6, TOPHYS(_MB_HW_ExceptionVectorTable) 349 bra r6 350 351full_exception_trapw: 352 RESTORE_STATE 353 bri full_exception_trap 354#else 355 /* Exceptions enabled here. This will allow nested exceptions */ 356 mfs r6, rmsr; 357 nop 358 swi r6, r1, 0; /* RMSR_OFFSET */ 359 ori r6, r6, 0x100; /* Turn ON the EE bit */ 360 andi r6, r6, ~2; /* Disable interrupts */ 361 mts rmsr, r6; 362 nop 363 364 xori r6, r5, 1; /* 00001 = Unaligned Exception */ 365 /* Jump to unalignment exception handler */ 366 beqi r6, handle_unaligned_ex; 367 368handle_other_ex: /* Handle Other exceptions here */ 369 /* Save other volatiles before we make procedure calls below */ 370 swi r7, r1, PT_R7 371 swi r8, r1, PT_R8 372 swi r9, r1, PT_R9 373 swi r10, r1, PT_R10 374 swi r11, r1, PT_R11 375 swi r12, r1, PT_R12 376 swi r14, r1, PT_R14 377 swi r15, r1, PT_R15 378 swi r18, r1, PT_R18 379 380 or r5, r1, r0 381 andi r6, r4, 0x1F; /* Load ESR[EC] */ 382 lwi r7, r0, PER_CPU(KM) /* MS: saving current kernel mode to regs */ 383 swi r7, r1, PT_MODE 384 mfs r7, rfsr 385 nop 386 addk r8, r17, r0; /* Load exception address */ 387 bralid r15, full_exception; /* Branch to the handler */ 388 nop; 389 mts rfsr, r0; /* Clear sticky fsr */ 390 nop 391 392 /* 393 * Trigger execution of the signal handler by enabling 394 * interrupts and calling an invalid syscall. 395 */ 396 mfs r5, rmsr; 397 nop 398 ori r5, r5, 2; 399 mts rmsr, r5; /* enable interrupt */ 400 nop 401 addi r12, r0, __NR_syscalls; 402 brki r14, 0x08; 403 mfs r5, rmsr; /* disable interrupt */ 404 nop 405 andi r5, r5, ~2; 406 mts rmsr, r5; 407 nop 408 409 lwi r7, r1, PT_R7 410 lwi r8, r1, PT_R8 411 lwi r9, r1, PT_R9 412 lwi r10, r1, PT_R10 413 lwi r11, r1, PT_R11 414 lwi r12, r1, PT_R12 415 lwi r14, r1, PT_R14 416 lwi r15, r1, PT_R15 417 lwi r18, r1, PT_R18 418 419 bri ex_handler_done; /* Complete exception handling */ 420#endif 421 422/* 0x01 - Unaligned data access exception 423 * This occurs when a word access is not aligned on a word boundary, 424 * or when a 16-bit access is not aligned on a 16-bit boundary. 425 * This handler perform the access, and returns, except for MMU when 426 * the unaligned address is last on a 4k page or the physical address is 427 * not found in the page table, in which case unaligned_data_trap is called. 428 */ 429handle_unaligned_ex: 430 /* Working registers already saved: R3, R4, R5, R6 431 * R4 = ESR 432 * R3 = EAR 433 */ 434#ifdef CONFIG_MMU 435 andi r6, r4, 0x1000 /* Check ESR[DS] */ 436 beqi r6, _no_delayslot /* Branch if ESR[DS] not set */ 437 mfs r17, rbtr; /* ESR[DS] set - return address in BTR */ 438 nop 439_no_delayslot: 440 /* jump to high level unaligned handler */ 441 RESTORE_STATE; 442 bri unaligned_data_trap 443#endif 444 andi r6, r4, 0x3E0; /* Mask and extract the register operand */ 445 srl r6, r6; /* r6 >> 5 */ 446 srl r6, r6; 447 srl r6, r6; 448 srl r6, r6; 449 srl r6, r6; 450 /* Store the register operand in a temporary location */ 451 sbi r6, r0, TOPHYS(ex_reg_op); 452 453 andi r6, r4, 0x400; /* Extract ESR[S] */ 454 bnei r6, ex_sw; 455ex_lw: 456 andi r6, r4, 0x800; /* Extract ESR[W] */ 457 beqi r6, ex_lhw; 458 lbui r5, r3, 0; /* Exception address in r3 */ 459 /* Load a word, byte-by-byte from destination address 460 and save it in tmp space */ 461 sbi r5, r0, TOPHYS(ex_tmp_data_loc_0); 462 lbui r5, r3, 1; 463 sbi r5, r0, TOPHYS(ex_tmp_data_loc_1); 464 lbui r5, r3, 2; 465 sbi r5, r0, TOPHYS(ex_tmp_data_loc_2); 466 lbui r5, r3, 3; 467 sbi r5, r0, TOPHYS(ex_tmp_data_loc_3); 468 /* Get the destination register value into r4 */ 469 lwi r4, r0, TOPHYS(ex_tmp_data_loc_0); 470 bri ex_lw_tail; 471ex_lhw: 472 lbui r5, r3, 0; /* Exception address in r3 */ 473 /* Load a half-word, byte-by-byte from destination 474 address and save it in tmp space */ 475 sbi r5, r0, TOPHYS(ex_tmp_data_loc_0); 476 lbui r5, r3, 1; 477 sbi r5, r0, TOPHYS(ex_tmp_data_loc_1); 478 /* Get the destination register value into r4 */ 479 lhui r4, r0, TOPHYS(ex_tmp_data_loc_0); 480ex_lw_tail: 481 /* Get the destination register number into r5 */ 482 lbui r5, r0, TOPHYS(ex_reg_op); 483 /* Form load_word jump table offset (lw_table + (8 * regnum)) */ 484 la r6, r0, TOPHYS(lw_table); 485 addk r5, r5, r5; 486 addk r5, r5, r5; 487 addk r5, r5, r5; 488 addk r5, r5, r6; 489 bra r5; 490ex_lw_end: /* Exception handling of load word, ends */ 491ex_sw: 492 /* Get the destination register number into r5 */ 493 lbui r5, r0, TOPHYS(ex_reg_op); 494 /* Form store_word jump table offset (sw_table + (8 * regnum)) */ 495 la r6, r0, TOPHYS(sw_table); 496 add r5, r5, r5; 497 add r5, r5, r5; 498 add r5, r5, r5; 499 add r5, r5, r6; 500 bra r5; 501ex_sw_tail: 502 mfs r6, resr; 503 nop 504 andi r6, r6, 0x800; /* Extract ESR[W] */ 505 beqi r6, ex_shw; 506 /* Get the word - delay slot */ 507 swi r4, r0, TOPHYS(ex_tmp_data_loc_0); 508 /* Store the word, byte-by-byte into destination address */ 509 lbui r4, r0, TOPHYS(ex_tmp_data_loc_0); 510 sbi r4, r3, 0; 511 lbui r4, r0, TOPHYS(ex_tmp_data_loc_1); 512 sbi r4, r3, 1; 513 lbui r4, r0, TOPHYS(ex_tmp_data_loc_2); 514 sbi r4, r3, 2; 515 lbui r4, r0, TOPHYS(ex_tmp_data_loc_3); 516 sbi r4, r3, 3; 517 bri ex_handler_done; 518 519ex_shw: 520 /* Store the lower half-word, byte-by-byte into destination address */ 521 swi r4, r0, TOPHYS(ex_tmp_data_loc_0); 522 lbui r4, r0, TOPHYS(ex_tmp_data_loc_2); 523 sbi r4, r3, 0; 524 lbui r4, r0, TOPHYS(ex_tmp_data_loc_3); 525 sbi r4, r3, 1; 526ex_sw_end: /* Exception handling of store word, ends. */ 527 528ex_handler_done: 529#ifndef CONFIG_MMU 530 lwi r5, r1, 0 /* RMSR */ 531 mts rmsr, r5 532 nop 533 lwi r3, r1, PT_R3 534 lwi r4, r1, PT_R4 535 lwi r5, r1, PT_R5 536 lwi r6, r1, PT_R6 537 lwi r17, r1, PT_R17 538 539 rted r17, 0 540 addik r1, r1, (EX_HANDLER_STACK_SIZ); /* Restore stack frame */ 541#else 542 RESTORE_STATE; 543 rted r17, 0 544 nop 545#endif 546 547#ifdef CONFIG_MMU 548 /* Exception vector entry code. This code runs with address translation 549 * turned off (i.e. using physical addresses). */ 550 551 /* Exception vectors. */ 552 553 /* 0x10 - Data Storage Exception 554 * This happens for just a few reasons. U0 set (but we don't do that), 555 * or zone protection fault (user violation, write to protected page). 556 * If this is just an update of modified status, we do that quickly 557 * and exit. Otherwise, we call heavyweight functions to do the work. 558 */ 559 handle_data_storage_exception: 560 /* Working registers already saved: R3, R4, R5, R6 561 * R3 = ESR 562 */ 563 mfs r11, rpid 564 nop 565 /* If we are faulting a kernel address, we have to use the 566 * kernel page tables. 567 */ 568 ori r5, r0, CONFIG_KERNEL_START 569 cmpu r5, r3, r5 570 bgti r5, ex3 571 /* First, check if it was a zone fault (which means a user 572 * tried to access a kernel or read-protected page - always 573 * a SEGV). All other faults here must be stores, so no 574 * need to check ESR_S as well. */ 575 andi r4, r4, 0x800 /* ESR_Z - zone protection */ 576 bnei r4, ex2 577 578 ori r4, r0, swapper_pg_dir 579 mts rpid, r0 /* TLB will have 0 TID */ 580 nop 581 bri ex4 582 583 /* Get the PGD for the current thread. */ 584 ex3: 585 /* First, check if it was a zone fault (which means a user 586 * tried to access a kernel or read-protected page - always 587 * a SEGV). All other faults here must be stores, so no 588 * need to check ESR_S as well. */ 589 andi r4, r4, 0x800 /* ESR_Z */ 590 bnei r4, ex2 591 /* get current task address */ 592 addi r4 ,CURRENT_TASK, TOPHYS(0); 593 lwi r4, r4, TASK_THREAD+PGDIR 594 ex4: 595 tophys(r4,r4) 596 BSRLI(r5,r3,20) /* Create L1 (pgdir/pmd) address */ 597 andi r5, r5, 0xffc 598/* Assume pgdir aligned on 4K boundary, no need for "andi r4,r4,0xfffff003" */ 599 or r4, r4, r5 600 lwi r4, r4, 0 /* Get L1 entry */ 601 andi r5, r4, 0xfffff000 /* Extract L2 (pte) base address */ 602 beqi r5, ex2 /* Bail if no table */ 603 604 tophys(r5,r5) 605 BSRLI(r6,r3,10) /* Compute PTE address */ 606 andi r6, r6, 0xffc 607 andi r5, r5, 0xfffff003 608 or r5, r5, r6 609 lwi r4, r5, 0 /* Get Linux PTE */ 610 611 andi r6, r4, _PAGE_RW /* Is it writeable? */ 612 beqi r6, ex2 /* Bail if not */ 613 614 /* Update 'changed' */ 615 ori r4, r4, _PAGE_DIRTY|_PAGE_ACCESSED|_PAGE_HWWRITE 616 swi r4, r5, 0 /* Update Linux page table */ 617 618 /* Most of the Linux PTE is ready to load into the TLB LO. 619 * We set ZSEL, where only the LS-bit determines user access. 620 * We set execute, because we don't have the granularity to 621 * properly set this at the page level (Linux problem). 622 * If shared is set, we cause a zero PID->TID load. 623 * Many of these bits are software only. Bits we don't set 624 * here we (properly should) assume have the appropriate value. 625 */ 626 andni r4, r4, 0x0ce2 /* Make sure 20, 21 are zero */ 627 ori r4, r4, _PAGE_HWEXEC /* make it executable */ 628 629 /* find the TLB index that caused the fault. It has to be here*/ 630 mts rtlbsx, r3 631 nop 632 mfs r5, rtlbx /* DEBUG: TBD */ 633 nop 634 mts rtlblo, r4 /* Load TLB LO */ 635 nop 636 /* Will sync shadow TLBs */ 637 638 /* Done...restore registers and get out of here. */ 639 mts rpid, r11 640 nop 641 bri 4 642 643 RESTORE_STATE; 644 rted r17, 0 645 nop 646 ex2: 647 /* The bailout. Restore registers to pre-exception conditions 648 * and call the heavyweights to help us out. */ 649 mts rpid, r11 650 nop 651 bri 4 652 RESTORE_STATE; 653 bri page_fault_data_trap 654 655 656 /* 0x11 - Instruction Storage Exception 657 * This is caused by a fetch from non-execute or guarded pages. */ 658 handle_instruction_storage_exception: 659 /* Working registers already saved: R3, R4, R5, R6 660 * R3 = ESR 661 */ 662 663 RESTORE_STATE; 664 bri page_fault_instr_trap 665 666 /* 0x12 - Data TLB Miss Exception 667 * As the name implies, translation is not in the MMU, so search the 668 * page tables and fix it. The only purpose of this function is to 669 * load TLB entries from the page table if they exist. 670 */ 671 handle_data_tlb_miss_exception: 672 /* Working registers already saved: R3, R4, R5, R6 673 * R3 = EAR, R4 = ESR 674 */ 675 mfs r11, rpid 676 nop 677 678 /* If we are faulting a kernel address, we have to use the 679 * kernel page tables. */ 680 ori r6, r0, CONFIG_KERNEL_START 681 cmpu r4, r3, r6 682 bgti r4, ex5 683 ori r4, r0, swapper_pg_dir 684 mts rpid, r0 /* TLB will have 0 TID */ 685 nop 686 bri ex6 687 688 /* Get the PGD for the current thread. */ 689 ex5: 690 /* get current task address */ 691 addi r4 ,CURRENT_TASK, TOPHYS(0); 692 lwi r4, r4, TASK_THREAD+PGDIR 693 ex6: 694 tophys(r4,r4) 695 BSRLI(r5,r3,20) /* Create L1 (pgdir/pmd) address */ 696 andi r5, r5, 0xffc 697/* Assume pgdir aligned on 4K boundary, no need for "andi r4,r4,0xfffff003" */ 698 or r4, r4, r5 699 lwi r4, r4, 0 /* Get L1 entry */ 700 andi r5, r4, 0xfffff000 /* Extract L2 (pte) base address */ 701 beqi r5, ex7 /* Bail if no table */ 702 703 tophys(r5,r5) 704 BSRLI(r6,r3,10) /* Compute PTE address */ 705 andi r6, r6, 0xffc 706 andi r5, r5, 0xfffff003 707 or r5, r5, r6 708 lwi r4, r5, 0 /* Get Linux PTE */ 709 710 andi r6, r4, _PAGE_PRESENT 711 beqi r6, ex7 712 713 ori r4, r4, _PAGE_ACCESSED 714 swi r4, r5, 0 715 716 /* Most of the Linux PTE is ready to load into the TLB LO. 717 * We set ZSEL, where only the LS-bit determines user access. 718 * We set execute, because we don't have the granularity to 719 * properly set this at the page level (Linux problem). 720 * If shared is set, we cause a zero PID->TID load. 721 * Many of these bits are software only. Bits we don't set 722 * here we (properly should) assume have the appropriate value. 723 */ 724 brid finish_tlb_load 725 andni r4, r4, 0x0ce2 /* Make sure 20, 21 are zero */ 726 ex7: 727 /* The bailout. Restore registers to pre-exception conditions 728 * and call the heavyweights to help us out. 729 */ 730 mts rpid, r11 731 nop 732 bri 4 733 RESTORE_STATE; 734 bri page_fault_data_trap 735 736 /* 0x13 - Instruction TLB Miss Exception 737 * Nearly the same as above, except we get our information from 738 * different registers and bailout to a different point. 739 */ 740 handle_instruction_tlb_miss_exception: 741 /* Working registers already saved: R3, R4, R5, R6 742 * R3 = ESR 743 */ 744 mfs r11, rpid 745 nop 746 747 /* If we are faulting a kernel address, we have to use the 748 * kernel page tables. 749 */ 750 ori r4, r0, CONFIG_KERNEL_START 751 cmpu r4, r3, r4 752 bgti r4, ex8 753 ori r4, r0, swapper_pg_dir 754 mts rpid, r0 /* TLB will have 0 TID */ 755 nop 756 bri ex9 757 758 /* Get the PGD for the current thread. */ 759 ex8: 760 /* get current task address */ 761 addi r4 ,CURRENT_TASK, TOPHYS(0); 762 lwi r4, r4, TASK_THREAD+PGDIR 763 ex9: 764 tophys(r4,r4) 765 BSRLI(r5,r3,20) /* Create L1 (pgdir/pmd) address */ 766 andi r5, r5, 0xffc 767/* Assume pgdir aligned on 4K boundary, no need for "andi r4,r4,0xfffff003" */ 768 or r4, r4, r5 769 lwi r4, r4, 0 /* Get L1 entry */ 770 andi r5, r4, 0xfffff000 /* Extract L2 (pte) base address */ 771 beqi r5, ex10 /* Bail if no table */ 772 773 tophys(r5,r5) 774 BSRLI(r6,r3,10) /* Compute PTE address */ 775 andi r6, r6, 0xffc 776 andi r5, r5, 0xfffff003 777 or r5, r5, r6 778 lwi r4, r5, 0 /* Get Linux PTE */ 779 780 andi r6, r4, _PAGE_PRESENT 781 beqi r6, ex10 782 783 ori r4, r4, _PAGE_ACCESSED 784 swi r4, r5, 0 785 786 /* Most of the Linux PTE is ready to load into the TLB LO. 787 * We set ZSEL, where only the LS-bit determines user access. 788 * We set execute, because we don't have the granularity to 789 * properly set this at the page level (Linux problem). 790 * If shared is set, we cause a zero PID->TID load. 791 * Many of these bits are software only. Bits we don't set 792 * here we (properly should) assume have the appropriate value. 793 */ 794 brid finish_tlb_load 795 andni r4, r4, 0x0ce2 /* Make sure 20, 21 are zero */ 796 ex10: 797 /* The bailout. Restore registers to pre-exception conditions 798 * and call the heavyweights to help us out. 799 */ 800 mts rpid, r11 801 nop 802 bri 4 803 RESTORE_STATE; 804 bri page_fault_instr_trap 805 806/* Both the instruction and data TLB miss get to this point to load the TLB. 807 * r3 - EA of fault 808 * r4 - TLB LO (info from Linux PTE) 809 * r5, r6 - available to use 810 * PID - loaded with proper value when we get here 811 * Upon exit, we reload everything and RFI. 812 * A common place to load the TLB. 813 */ 814 tlb_index: 815 .long 1 /* MS: storing last used tlb index */ 816 finish_tlb_load: 817 /* MS: load the last used TLB index. */ 818 lwi r5, r0, TOPHYS(tlb_index) 819 addik r5, r5, 1 /* MS: inc tlb_index -> use next one */ 820 821/* MS: FIXME this is potential fault, because this is mask not count */ 822 andi r5, r5, (MICROBLAZE_TLB_SIZE-1) 823 ori r6, r0, 1 824 cmp r31, r5, r6 825 blti r31, ex12 826 addik r5, r6, 1 827 ex12: 828 /* MS: save back current TLB index */ 829 swi r5, r0, TOPHYS(tlb_index) 830 831 ori r4, r4, _PAGE_HWEXEC /* make it executable */ 832 mts rtlbx, r5 /* MS: save current TLB */ 833 nop 834 mts rtlblo, r4 /* MS: save to TLB LO */ 835 nop 836 837 /* Create EPN. This is the faulting address plus a static 838 * set of bits. These are size, valid, E, U0, and ensure 839 * bits 20 and 21 are zero. 840 */ 841 andi r3, r3, 0xfffff000 842 ori r3, r3, 0x0c0 843 mts rtlbhi, r3 /* Load TLB HI */ 844 nop 845 846 /* Done...restore registers and get out of here. */ 847 mts rpid, r11 848 nop 849 bri 4 850 RESTORE_STATE; 851 rted r17, 0 852 nop 853 854 /* extern void giveup_fpu(struct task_struct *prev) 855 * 856 * The MicroBlaze processor may have an FPU, so this should not just 857 * return: TBD. 858 */ 859 .globl giveup_fpu; 860 .align 4; 861 giveup_fpu: 862 bralid r15,0 /* TBD */ 863 nop 864 865 /* At present, this routine just hangs. - extern void abort(void) */ 866 .globl abort; 867 .align 4; 868 abort: 869 br r0 870 871 .globl set_context; 872 .align 4; 873 set_context: 874 mts rpid, r5 /* Shadow TLBs are automatically */ 875 nop 876 bri 4 /* flushed by changing PID */ 877 rtsd r15,8 878 nop 879 880#endif 881.end _hw_exception_handler 882 883#ifdef CONFIG_MMU 884/* Unaligned data access exception last on a 4k page for MMU. 885 * When this is called, we are in virtual mode with exceptions enabled 886 * and registers 1-13,15,17,18 saved. 887 * 888 * R3 = ESR 889 * R4 = EAR 890 * R7 = pointer to saved registers (struct pt_regs *regs) 891 * 892 * This handler perform the access, and returns via ret_from_exc. 893 */ 894.global _unaligned_data_exception 895.ent _unaligned_data_exception 896_unaligned_data_exception: 897 andi r8, r3, 0x3E0; /* Mask and extract the register operand */ 898 BSRLI(r8,r8,2); /* r8 >> 2 = register operand * 8 */ 899 andi r6, r3, 0x400; /* Extract ESR[S] */ 900 bneid r6, ex_sw_vm; 901 andi r6, r3, 0x800; /* Extract ESR[W] - delay slot */ 902ex_lw_vm: 903 beqid r6, ex_lhw_vm; 904load1: lbui r5, r4, 0; /* Exception address in r4 - delay slot */ 905/* Load a word, byte-by-byte from destination address and save it in tmp space*/ 906 la r6, r0, ex_tmp_data_loc_0; 907 sbi r5, r6, 0; 908load2: lbui r5, r4, 1; 909 sbi r5, r6, 1; 910load3: lbui r5, r4, 2; 911 sbi r5, r6, 2; 912load4: lbui r5, r4, 3; 913 sbi r5, r6, 3; 914 brid ex_lw_tail_vm; 915/* Get the destination register value into r3 - delay slot */ 916 lwi r3, r6, 0; 917ex_lhw_vm: 918 /* Load a half-word, byte-by-byte from destination address and 919 * save it in tmp space */ 920 la r6, r0, ex_tmp_data_loc_0; 921 sbi r5, r6, 0; 922load5: lbui r5, r4, 1; 923 sbi r5, r6, 1; 924 lhui r3, r6, 0; /* Get the destination register value into r3 */ 925ex_lw_tail_vm: 926 /* Form load_word jump table offset (lw_table_vm + (8 * regnum)) */ 927 addik r5, r8, lw_table_vm; 928 bra r5; 929ex_lw_end_vm: /* Exception handling of load word, ends */ 930 brai ret_from_exc; 931ex_sw_vm: 932/* Form store_word jump table offset (sw_table_vm + (8 * regnum)) */ 933 addik r5, r8, sw_table_vm; 934 bra r5; 935ex_sw_tail_vm: 936 la r5, r0, ex_tmp_data_loc_0; 937 beqid r6, ex_shw_vm; 938 swi r3, r5, 0; /* Get the word - delay slot */ 939 /* Store the word, byte-by-byte into destination address */ 940 lbui r3, r5, 0; 941store1: sbi r3, r4, 0; 942 lbui r3, r5, 1; 943store2: sbi r3, r4, 1; 944 lbui r3, r5, 2; 945store3: sbi r3, r4, 2; 946 lbui r3, r5, 3; 947 brid ret_from_exc; 948store4: sbi r3, r4, 3; /* Delay slot */ 949ex_shw_vm: 950 /* Store the lower half-word, byte-by-byte into destination address */ 951 lbui r3, r5, 2; 952store5: sbi r3, r4, 0; 953 lbui r3, r5, 3; 954 brid ret_from_exc; 955store6: sbi r3, r4, 1; /* Delay slot */ 956ex_sw_end_vm: /* Exception handling of store word, ends. */ 957 958/* We have to prevent cases that get/put_user macros get unaligned pointer 959 * to bad page area. We have to find out which origin instruction caused it 960 * and called fixup for that origin instruction not instruction in unaligned 961 * handler */ 962ex_unaligned_fixup: 963 ori r5, r7, 0 /* setup pointer to pt_regs */ 964 lwi r6, r7, PT_PC; /* faulting address is one instruction above */ 965 addik r6, r6, -4 /* for finding proper fixup */ 966 swi r6, r7, PT_PC; /* a save back it to PT_PC */ 967 addik r7, r0, SIGSEGV 968 /* call bad_page_fault for finding aligned fixup, fixup address is saved 969 * in PT_PC which is used as return address from exception */ 970 la r15, r0, ret_from_exc-8 /* setup return address */ 971 brid bad_page_fault 972 nop 973 974/* We prevent all load/store because it could failed any attempt to access */ 975.section __ex_table,"a"; 976 .word load1,ex_unaligned_fixup; 977 .word load2,ex_unaligned_fixup; 978 .word load3,ex_unaligned_fixup; 979 .word load4,ex_unaligned_fixup; 980 .word load5,ex_unaligned_fixup; 981 .word store1,ex_unaligned_fixup; 982 .word store2,ex_unaligned_fixup; 983 .word store3,ex_unaligned_fixup; 984 .word store4,ex_unaligned_fixup; 985 .word store5,ex_unaligned_fixup; 986 .word store6,ex_unaligned_fixup; 987.previous; 988.end _unaligned_data_exception 989#endif /* CONFIG_MMU */ 990 991ex_handler_unhandled: 992/* FIXME add handle function for unhandled exception - dump register */ 993 bri 0 994 995/* 996 * hw_exception_handler Jump Table 997 * - Contains code snippets for each register that caused the unalign exception 998 * - Hence exception handler is NOT self-modifying 999 * - Separate table for load exceptions and store exceptions. 1000 * - Each table is of size: (8 * 32) = 256 bytes 1001 */ 1002 1003.section .text 1004.align 4 1005lw_table: 1006lw_r0: R3_TO_LWREG (0); 1007lw_r1: LWREG_NOP; 1008lw_r2: R3_TO_LWREG (2); 1009lw_r3: R3_TO_LWREG_V (3); 1010lw_r4: R3_TO_LWREG_V (4); 1011lw_r5: R3_TO_LWREG_V (5); 1012lw_r6: R3_TO_LWREG_V (6); 1013lw_r7: R3_TO_LWREG (7); 1014lw_r8: R3_TO_LWREG (8); 1015lw_r9: R3_TO_LWREG (9); 1016lw_r10: R3_TO_LWREG (10); 1017lw_r11: R3_TO_LWREG (11); 1018lw_r12: R3_TO_LWREG (12); 1019lw_r13: R3_TO_LWREG (13); 1020lw_r14: R3_TO_LWREG (14); 1021lw_r15: R3_TO_LWREG (15); 1022lw_r16: R3_TO_LWREG (16); 1023lw_r17: LWREG_NOP; 1024lw_r18: R3_TO_LWREG (18); 1025lw_r19: R3_TO_LWREG (19); 1026lw_r20: R3_TO_LWREG (20); 1027lw_r21: R3_TO_LWREG (21); 1028lw_r22: R3_TO_LWREG (22); 1029lw_r23: R3_TO_LWREG (23); 1030lw_r24: R3_TO_LWREG (24); 1031lw_r25: R3_TO_LWREG (25); 1032lw_r26: R3_TO_LWREG (26); 1033lw_r27: R3_TO_LWREG (27); 1034lw_r28: R3_TO_LWREG (28); 1035lw_r29: R3_TO_LWREG (29); 1036lw_r30: R3_TO_LWREG (30); 1037#ifdef CONFIG_MMU 1038lw_r31: R3_TO_LWREG_V (31); 1039#else 1040lw_r31: R3_TO_LWREG (31); 1041#endif 1042 1043sw_table: 1044sw_r0: SWREG_TO_R3 (0); 1045sw_r1: SWREG_NOP; 1046sw_r2: SWREG_TO_R3 (2); 1047sw_r3: SWREG_TO_R3_V (3); 1048sw_r4: SWREG_TO_R3_V (4); 1049sw_r5: SWREG_TO_R3_V (5); 1050sw_r6: SWREG_TO_R3_V (6); 1051sw_r7: SWREG_TO_R3 (7); 1052sw_r8: SWREG_TO_R3 (8); 1053sw_r9: SWREG_TO_R3 (9); 1054sw_r10: SWREG_TO_R3 (10); 1055sw_r11: SWREG_TO_R3 (11); 1056sw_r12: SWREG_TO_R3 (12); 1057sw_r13: SWREG_TO_R3 (13); 1058sw_r14: SWREG_TO_R3 (14); 1059sw_r15: SWREG_TO_R3 (15); 1060sw_r16: SWREG_TO_R3 (16); 1061sw_r17: SWREG_NOP; 1062sw_r18: SWREG_TO_R3 (18); 1063sw_r19: SWREG_TO_R3 (19); 1064sw_r20: SWREG_TO_R3 (20); 1065sw_r21: SWREG_TO_R3 (21); 1066sw_r22: SWREG_TO_R3 (22); 1067sw_r23: SWREG_TO_R3 (23); 1068sw_r24: SWREG_TO_R3 (24); 1069sw_r25: SWREG_TO_R3 (25); 1070sw_r26: SWREG_TO_R3 (26); 1071sw_r27: SWREG_TO_R3 (27); 1072sw_r28: SWREG_TO_R3 (28); 1073sw_r29: SWREG_TO_R3 (29); 1074sw_r30: SWREG_TO_R3 (30); 1075#ifdef CONFIG_MMU 1076sw_r31: SWREG_TO_R3_V (31); 1077#else 1078sw_r31: SWREG_TO_R3 (31); 1079#endif 1080 1081#ifdef CONFIG_MMU 1082lw_table_vm: 1083lw_r0_vm: R3_TO_LWREG_VM (0); 1084lw_r1_vm: R3_TO_LWREG_VM_V (1); 1085lw_r2_vm: R3_TO_LWREG_VM_V (2); 1086lw_r3_vm: R3_TO_LWREG_VM_V (3); 1087lw_r4_vm: R3_TO_LWREG_VM_V (4); 1088lw_r5_vm: R3_TO_LWREG_VM_V (5); 1089lw_r6_vm: R3_TO_LWREG_VM_V (6); 1090lw_r7_vm: R3_TO_LWREG_VM_V (7); 1091lw_r8_vm: R3_TO_LWREG_VM_V (8); 1092lw_r9_vm: R3_TO_LWREG_VM_V (9); 1093lw_r10_vm: R3_TO_LWREG_VM_V (10); 1094lw_r11_vm: R3_TO_LWREG_VM_V (11); 1095lw_r12_vm: R3_TO_LWREG_VM_V (12); 1096lw_r13_vm: R3_TO_LWREG_VM_V (13); 1097lw_r14_vm: R3_TO_LWREG_VM (14); 1098lw_r15_vm: R3_TO_LWREG_VM_V (15); 1099lw_r16_vm: R3_TO_LWREG_VM (16); 1100lw_r17_vm: R3_TO_LWREG_VM_V (17); 1101lw_r18_vm: R3_TO_LWREG_VM_V (18); 1102lw_r19_vm: R3_TO_LWREG_VM (19); 1103lw_r20_vm: R3_TO_LWREG_VM (20); 1104lw_r21_vm: R3_TO_LWREG_VM (21); 1105lw_r22_vm: R3_TO_LWREG_VM (22); 1106lw_r23_vm: R3_TO_LWREG_VM (23); 1107lw_r24_vm: R3_TO_LWREG_VM (24); 1108lw_r25_vm: R3_TO_LWREG_VM (25); 1109lw_r26_vm: R3_TO_LWREG_VM (26); 1110lw_r27_vm: R3_TO_LWREG_VM (27); 1111lw_r28_vm: R3_TO_LWREG_VM (28); 1112lw_r29_vm: R3_TO_LWREG_VM (29); 1113lw_r30_vm: R3_TO_LWREG_VM (30); 1114lw_r31_vm: R3_TO_LWREG_VM_V (31); 1115 1116sw_table_vm: 1117sw_r0_vm: SWREG_TO_R3_VM (0); 1118sw_r1_vm: SWREG_TO_R3_VM_V (1); 1119sw_r2_vm: SWREG_TO_R3_VM_V (2); 1120sw_r3_vm: SWREG_TO_R3_VM_V (3); 1121sw_r4_vm: SWREG_TO_R3_VM_V (4); 1122sw_r5_vm: SWREG_TO_R3_VM_V (5); 1123sw_r6_vm: SWREG_TO_R3_VM_V (6); 1124sw_r7_vm: SWREG_TO_R3_VM_V (7); 1125sw_r8_vm: SWREG_TO_R3_VM_V (8); 1126sw_r9_vm: SWREG_TO_R3_VM_V (9); 1127sw_r10_vm: SWREG_TO_R3_VM_V (10); 1128sw_r11_vm: SWREG_TO_R3_VM_V (11); 1129sw_r12_vm: SWREG_TO_R3_VM_V (12); 1130sw_r13_vm: SWREG_TO_R3_VM_V (13); 1131sw_r14_vm: SWREG_TO_R3_VM (14); 1132sw_r15_vm: SWREG_TO_R3_VM_V (15); 1133sw_r16_vm: SWREG_TO_R3_VM (16); 1134sw_r17_vm: SWREG_TO_R3_VM_V (17); 1135sw_r18_vm: SWREG_TO_R3_VM_V (18); 1136sw_r19_vm: SWREG_TO_R3_VM (19); 1137sw_r20_vm: SWREG_TO_R3_VM (20); 1138sw_r21_vm: SWREG_TO_R3_VM (21); 1139sw_r22_vm: SWREG_TO_R3_VM (22); 1140sw_r23_vm: SWREG_TO_R3_VM (23); 1141sw_r24_vm: SWREG_TO_R3_VM (24); 1142sw_r25_vm: SWREG_TO_R3_VM (25); 1143sw_r26_vm: SWREG_TO_R3_VM (26); 1144sw_r27_vm: SWREG_TO_R3_VM (27); 1145sw_r28_vm: SWREG_TO_R3_VM (28); 1146sw_r29_vm: SWREG_TO_R3_VM (29); 1147sw_r30_vm: SWREG_TO_R3_VM (30); 1148sw_r31_vm: SWREG_TO_R3_VM_V (31); 1149#endif /* CONFIG_MMU */ 1150 1151/* Temporary data structures used in the handler */ 1152.section .data 1153.align 4 1154ex_tmp_data_loc_0: 1155 .byte 0 1156ex_tmp_data_loc_1: 1157 .byte 0 1158ex_tmp_data_loc_2: 1159 .byte 0 1160ex_tmp_data_loc_3: 1161 .byte 0 1162ex_reg_op: 1163 .byte 0 1164