1/* 2 * PowerPC version 3 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 4 * Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP 5 * Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu> 6 * Low-level exception handlers and MMU support 7 * rewritten by Paul Mackerras. 8 * Copyright (C) 1996 Paul Mackerras. 9 * MPC8xx modifications by Dan Malek 10 * Copyright (C) 1997 Dan Malek (dmalek@jlc.net). 11 * 12 * This file contains low-level support and setup for PowerPC 8xx 13 * embedded processors, including trap and interrupt dispatch. 14 * 15 * This program is free software; you can redistribute it and/or 16 * modify it under the terms of the GNU General Public License 17 * as published by the Free Software Foundation; either version 18 * 2 of the License, or (at your option) any later version. 19 * 20 */ 21 22#include <linux/init.h> 23#include <asm/processor.h> 24#include <asm/page.h> 25#include <asm/mmu.h> 26#include <asm/cache.h> 27#include <asm/pgtable.h> 28#include <asm/cputable.h> 29#include <asm/thread_info.h> 30#include <asm/ppc_asm.h> 31#include <asm/asm-offsets.h> 32#include <asm/ptrace.h> 33#include <asm/export.h> 34#include <asm/code-patching-asm.h> 35 36#if CONFIG_TASK_SIZE <= 0x80000000 && CONFIG_PAGE_OFFSET >= 0x80000000 37/* By simply checking Address >= 0x80000000, we know if its a kernel address */ 38#define SIMPLE_KERNEL_ADDRESS 1 39#endif 40 41/* 42 * We need an ITLB miss handler for kernel addresses if: 43 * - Either we have modules 44 * - Or we have not pinned the first 8M 45 */ 46#if defined(CONFIG_MODULES) || !defined(CONFIG_PIN_TLB_TEXT) || \ 47 defined(CONFIG_DEBUG_PAGEALLOC) 48#define ITLB_MISS_KERNEL 1 49#endif 50 51/* 52 * Value for the bits that have fixed value in RPN entries. 53 * Also used for tagging DAR for DTLBerror. 54 */ 55#define RPN_PATTERN 0x00f0 56 57#define PAGE_SHIFT_512K 19 58#define PAGE_SHIFT_8M 23 59 60 __HEAD 61_ENTRY(_stext); 62_ENTRY(_start); 63 64/* MPC8xx 65 * This port was done on an MBX board with an 860. Right now I only 66 * support an ELF compressed (zImage) boot from EPPC-Bug because the 67 * code there loads up some registers before calling us: 68 * r3: ptr to board info data 69 * r4: initrd_start or if no initrd then 0 70 * r5: initrd_end - unused if r4 is 0 71 * r6: Start of command line string 72 * r7: End of command line string 73 * 74 * I decided to use conditional compilation instead of checking PVR and 75 * adding more processor specific branches around code I don't need. 76 * Since this is an embedded processor, I also appreciate any memory 77 * savings I can get. 78 * 79 * The MPC8xx does not have any BATs, but it supports large page sizes. 80 * We first initialize the MMU to support 8M byte pages, then load one 81 * entry into each of the instruction and data TLBs to map the first 82 * 8M 1:1. I also mapped an additional I/O space 1:1 so we can get to 83 * the "internal" processor registers before MMU_init is called. 84 * 85 * -- Dan 86 */ 87 .globl __start 88__start: 89 mr r31,r3 /* save device tree ptr */ 90 91 /* We have to turn on the MMU right away so we get cache modes 92 * set correctly. 93 */ 94 bl initial_mmu 95 96/* We now have the lower 8 Meg mapped into TLB entries, and the caches 97 * ready to work. 98 */ 99 100turn_on_mmu: 101 mfmsr r0 102 ori r0,r0,MSR_DR|MSR_IR 103 mtspr SPRN_SRR1,r0 104 lis r0,start_here@h 105 ori r0,r0,start_here@l 106 mtspr SPRN_SRR0,r0 107 rfi /* enables MMU */ 108 109 110#ifdef CONFIG_PERF_EVENTS 111 .align 4 112 113 .globl itlb_miss_counter 114itlb_miss_counter: 115 .space 4 116 117 .globl dtlb_miss_counter 118dtlb_miss_counter: 119 .space 4 120 121 .globl instruction_counter 122instruction_counter: 123 .space 4 124#endif 125 126/* 127 * Exception entry code. This code runs with address translation 128 * turned off, i.e. using physical addresses. 129 * We assume sprg3 has the physical address of the current 130 * task's thread_struct. 131 */ 132#define EXCEPTION_PROLOG \ 133 mtspr SPRN_SPRG_SCRATCH0, r10; \ 134 mtspr SPRN_SPRG_SCRATCH1, r11; \ 135 mfcr r10; \ 136 EXCEPTION_PROLOG_1; \ 137 EXCEPTION_PROLOG_2 138 139#define EXCEPTION_PROLOG_1 \ 140 mfspr r11,SPRN_SRR1; /* check whether user or kernel */ \ 141 andi. r11,r11,MSR_PR; \ 142 tophys(r11,r1); /* use tophys(r1) if kernel */ \ 143 beq 1f; \ 144 mfspr r11,SPRN_SPRG_THREAD; \ 145 lwz r11,THREAD_INFO-THREAD(r11); \ 146 addi r11,r11,THREAD_SIZE; \ 147 tophys(r11,r11); \ 1481: subi r11,r11,INT_FRAME_SIZE /* alloc exc. frame */ 149 150 151#define EXCEPTION_PROLOG_2 \ 152 stw r10,_CCR(r11); /* save registers */ \ 153 stw r12,GPR12(r11); \ 154 stw r9,GPR9(r11); \ 155 mfspr r10,SPRN_SPRG_SCRATCH0; \ 156 stw r10,GPR10(r11); \ 157 mfspr r12,SPRN_SPRG_SCRATCH1; \ 158 stw r12,GPR11(r11); \ 159 mflr r10; \ 160 stw r10,_LINK(r11); \ 161 mfspr r12,SPRN_SRR0; \ 162 mfspr r9,SPRN_SRR1; \ 163 stw r1,GPR1(r11); \ 164 stw r1,0(r11); \ 165 tovirt(r1,r11); /* set new kernel sp */ \ 166 li r10,MSR_KERNEL & ~(MSR_IR|MSR_DR); /* can take exceptions */ \ 167 mtmsr r10; \ 168 stw r0,GPR0(r11); \ 169 lis r10, STACK_FRAME_REGS_MARKER@ha; /* exception frame marker */ \ 170 addi r10, r10, STACK_FRAME_REGS_MARKER@l; \ 171 stw r10, 8(r11); \ 172 SAVE_4GPRS(3, r11); \ 173 SAVE_2GPRS(7, r11) 174 175/* 176 * Note: code which follows this uses cr0.eq (set if from kernel), 177 * r11, r12 (SRR0), and r9 (SRR1). 178 * 179 * Note2: once we have set r1 we are in a position to take exceptions 180 * again, and we could thus set MSR:RI at that point. 181 */ 182 183/* 184 * Exception vectors. 185 */ 186#define EXCEPTION(n, label, hdlr, xfer) \ 187 . = n; \ 188label: \ 189 EXCEPTION_PROLOG; \ 190 addi r3,r1,STACK_FRAME_OVERHEAD; \ 191 xfer(n, hdlr) 192 193#define EXC_XFER_TEMPLATE(n, hdlr, trap, copyee, tfer, ret) \ 194 li r10,trap; \ 195 stw r10,_TRAP(r11); \ 196 li r10,MSR_KERNEL; \ 197 copyee(r10, r9); \ 198 bl tfer; \ 199i##n: \ 200 .long hdlr; \ 201 .long ret 202 203#define COPY_EE(d, s) rlwimi d,s,0,16,16 204#define NOCOPY(d, s) 205 206#define EXC_XFER_STD(n, hdlr) \ 207 EXC_XFER_TEMPLATE(n, hdlr, n, NOCOPY, transfer_to_handler_full, \ 208 ret_from_except_full) 209 210#define EXC_XFER_LITE(n, hdlr) \ 211 EXC_XFER_TEMPLATE(n, hdlr, n+1, NOCOPY, transfer_to_handler, \ 212 ret_from_except) 213 214#define EXC_XFER_EE(n, hdlr) \ 215 EXC_XFER_TEMPLATE(n, hdlr, n, COPY_EE, transfer_to_handler_full, \ 216 ret_from_except_full) 217 218#define EXC_XFER_EE_LITE(n, hdlr) \ 219 EXC_XFER_TEMPLATE(n, hdlr, n+1, COPY_EE, transfer_to_handler, \ 220 ret_from_except) 221 222/* System reset */ 223 EXCEPTION(0x100, Reset, system_reset_exception, EXC_XFER_STD) 224 225/* Machine check */ 226 . = 0x200 227MachineCheck: 228 EXCEPTION_PROLOG 229 mfspr r4,SPRN_DAR 230 stw r4,_DAR(r11) 231 li r5,RPN_PATTERN 232 mtspr SPRN_DAR,r5 /* Tag DAR, to be used in DTLB Error */ 233 mfspr r5,SPRN_DSISR 234 stw r5,_DSISR(r11) 235 addi r3,r1,STACK_FRAME_OVERHEAD 236 EXC_XFER_STD(0x200, machine_check_exception) 237 238/* Data access exception. 239 * This is "never generated" by the MPC8xx. 240 */ 241 . = 0x300 242DataAccess: 243 244/* Instruction access exception. 245 * This is "never generated" by the MPC8xx. 246 */ 247 . = 0x400 248InstructionAccess: 249 250/* External interrupt */ 251 EXCEPTION(0x500, HardwareInterrupt, do_IRQ, EXC_XFER_LITE) 252 253/* Alignment exception */ 254 . = 0x600 255Alignment: 256 EXCEPTION_PROLOG 257 mfspr r4,SPRN_DAR 258 stw r4,_DAR(r11) 259 li r5,RPN_PATTERN 260 mtspr SPRN_DAR,r5 /* Tag DAR, to be used in DTLB Error */ 261 mfspr r5,SPRN_DSISR 262 stw r5,_DSISR(r11) 263 addi r3,r1,STACK_FRAME_OVERHEAD 264 EXC_XFER_EE(0x600, alignment_exception) 265 266/* Program check exception */ 267 EXCEPTION(0x700, ProgramCheck, program_check_exception, EXC_XFER_STD) 268 269/* No FPU on MPC8xx. This exception is not supposed to happen. 270*/ 271 EXCEPTION(0x800, FPUnavailable, unknown_exception, EXC_XFER_STD) 272 273/* Decrementer */ 274 EXCEPTION(0x900, Decrementer, timer_interrupt, EXC_XFER_LITE) 275 276 EXCEPTION(0xa00, Trap_0a, unknown_exception, EXC_XFER_EE) 277 EXCEPTION(0xb00, Trap_0b, unknown_exception, EXC_XFER_EE) 278 279/* System call */ 280 . = 0xc00 281SystemCall: 282 EXCEPTION_PROLOG 283 EXC_XFER_EE_LITE(0xc00, DoSyscall) 284 285/* Single step - not used on 601 */ 286 EXCEPTION(0xd00, SingleStep, single_step_exception, EXC_XFER_STD) 287 EXCEPTION(0xe00, Trap_0e, unknown_exception, EXC_XFER_EE) 288 EXCEPTION(0xf00, Trap_0f, unknown_exception, EXC_XFER_EE) 289 290/* On the MPC8xx, this is a software emulation interrupt. It occurs 291 * for all unimplemented and illegal instructions. 292 */ 293 EXCEPTION(0x1000, SoftEmu, program_check_exception, EXC_XFER_STD) 294 295 . = 0x1100 296/* 297 * For the MPC8xx, this is a software tablewalk to load the instruction 298 * TLB. The task switch loads the M_TWB register with the pointer to the first 299 * level table. 300 * If we discover there is no second level table (value is zero) or if there 301 * is an invalid pte, we load that into the TLB, which causes another fault 302 * into the TLB Error interrupt where we can handle such problems. 303 * We have to use the MD_xxx registers for the tablewalk because the 304 * equivalent MI_xxx registers only perform the attribute functions. 305 */ 306 307#ifdef CONFIG_8xx_CPU15 308#define INVALIDATE_ADJACENT_PAGES_CPU15(addr) \ 309 addi addr, addr, PAGE_SIZE; \ 310 tlbie addr; \ 311 addi addr, addr, -(PAGE_SIZE << 1); \ 312 tlbie addr; \ 313 addi addr, addr, PAGE_SIZE 314#else 315#define INVALIDATE_ADJACENT_PAGES_CPU15(addr) 316#endif 317 318InstructionTLBMiss: 319 mtspr SPRN_SPRG_SCRATCH0, r10 320#if defined(ITLB_MISS_KERNEL) || defined(CONFIG_SWAP) 321 mtspr SPRN_SPRG_SCRATCH1, r11 322#endif 323 324 /* If we are faulting a kernel address, we have to use the 325 * kernel page tables. 326 */ 327 mfspr r10, SPRN_SRR0 /* Get effective address of fault */ 328 INVALIDATE_ADJACENT_PAGES_CPU15(r10) 329 mtspr SPRN_MD_EPN, r10 330 /* Only modules will cause ITLB Misses as we always 331 * pin the first 8MB of kernel memory */ 332#ifdef ITLB_MISS_KERNEL 333 mfcr r11 334#if defined(SIMPLE_KERNEL_ADDRESS) && defined(CONFIG_PIN_TLB_TEXT) 335 cmpi cr0, r10, 0 /* Address >= 0x80000000 */ 336#else 337 rlwinm r10, r10, 16, 0xfff8 338 cmpli cr0, r10, PAGE_OFFSET@h 339#ifndef CONFIG_PIN_TLB_TEXT 340 /* It is assumed that kernel code fits into the first 8M page */ 3410: cmpli cr7, r10, (PAGE_OFFSET + 0x0800000)@h 342 patch_site 0b, patch__itlbmiss_linmem_top 343#endif 344#endif 345#endif 346 mfspr r10, SPRN_M_TWB /* Get level 1 table */ 347#ifdef ITLB_MISS_KERNEL 348#if defined(SIMPLE_KERNEL_ADDRESS) && defined(CONFIG_PIN_TLB_TEXT) 349 bge+ 3f 350#else 351 blt+ 3f 352#endif 353#ifndef CONFIG_PIN_TLB_TEXT 354 blt cr7, ITLBMissLinear 355#endif 356 rlwinm r10, r10, 0, 20, 31 357 oris r10, r10, (swapper_pg_dir - PAGE_OFFSET)@ha 3583: 359#endif 360 lwz r10, (swapper_pg_dir-PAGE_OFFSET)@l(r10) /* Get level 1 entry */ 361 mtspr SPRN_MI_TWC, r10 /* Set segment attributes */ 362 363 mtspr SPRN_MD_TWC, r10 364 mfspr r10, SPRN_MD_TWC 365 lwz r10, 0(r10) /* Get the pte */ 366#ifdef ITLB_MISS_KERNEL 367 mtcr r11 368#endif 369#ifdef CONFIG_SWAP 370 rlwinm r11, r10, 32-5, _PAGE_PRESENT 371 and r11, r11, r10 372 rlwimi r10, r11, 0, _PAGE_PRESENT 373#endif 374 /* The Linux PTE won't go exactly into the MMU TLB. 375 * Software indicator bits 20 and 23 must be clear. 376 * Software indicator bits 22, 24, 25, 26, and 27 must be 377 * set. All other Linux PTE bits control the behavior 378 * of the MMU. 379 */ 380 rlwimi r10, r10, 0, 0x0f00 /* Clear bits 20-23 */ 381 rlwimi r10, r10, 4, 0x0400 /* Copy _PAGE_EXEC into bit 21 */ 382 ori r10, r10, RPN_PATTERN | 0x200 /* Set 22 and 24-27 */ 383 mtspr SPRN_MI_RPN, r10 /* Update TLB entry */ 384 385 /* Restore registers */ 3860: mfspr r10, SPRN_SPRG_SCRATCH0 387#if defined(ITLB_MISS_KERNEL) || defined(CONFIG_SWAP) 388 mfspr r11, SPRN_SPRG_SCRATCH1 389#endif 390 rfi 391 patch_site 0b, patch__itlbmiss_exit_1 392 393#ifdef CONFIG_PERF_EVENTS 394 patch_site 0f, patch__itlbmiss_perf 3950: lwz r10, (itlb_miss_counter - PAGE_OFFSET)@l(0) 396 addi r10, r10, 1 397 stw r10, (itlb_miss_counter - PAGE_OFFSET)@l(0) 398 mfspr r10, SPRN_SPRG_SCRATCH0 399#if defined(ITLB_MISS_KERNEL) || defined(CONFIG_SWAP) 400 mfspr r11, SPRN_SPRG_SCRATCH1 401#endif 402 rfi 403#endif 404 405#ifndef CONFIG_PIN_TLB_TEXT 406ITLBMissLinear: 407 mtcr r11 408 /* Set 8M byte page and mark it valid */ 409 li r11, MI_PS8MEG | MI_SVALID 410 mtspr SPRN_MI_TWC, r11 411 rlwinm r10, r10, 20, 0x0f800000 /* 8xx supports max 256Mb RAM */ 412 ori r10, r10, 0xf0 | MI_SPS16K | _PAGE_SH | _PAGE_DIRTY | \ 413 _PAGE_PRESENT 414 mtspr SPRN_MI_RPN, r10 /* Update TLB entry */ 415 4160: mfspr r10, SPRN_SPRG_SCRATCH0 417 mfspr r11, SPRN_SPRG_SCRATCH1 418 rfi 419 patch_site 0b, patch__itlbmiss_exit_2 420#endif 421 422 . = 0x1200 423DataStoreTLBMiss: 424 mtspr SPRN_SPRG_SCRATCH0, r10 425 mtspr SPRN_SPRG_SCRATCH1, r11 426 mfcr r11 427 428 /* If we are faulting a kernel address, we have to use the 429 * kernel page tables. 430 */ 431 mfspr r10, SPRN_MD_EPN 432 rlwinm r10, r10, 16, 0xfff8 433 cmpli cr0, r10, PAGE_OFFSET@h 434#ifndef CONFIG_PIN_TLB_IMMR 435 cmpli cr6, r10, VIRT_IMMR_BASE@h 436#endif 4370: cmpli cr7, r10, (PAGE_OFFSET + 0x1800000)@h 438 patch_site 0b, patch__dtlbmiss_linmem_top 439 440 mfspr r10, SPRN_M_TWB /* Get level 1 table */ 441 blt+ 3f 442#ifndef CONFIG_PIN_TLB_IMMR 4430: beq- cr6, DTLBMissIMMR 444 patch_site 0b, patch__dtlbmiss_immr_jmp 445#endif 446 blt cr7, DTLBMissLinear 447 rlwinm r10, r10, 0, 20, 31 448 oris r10, r10, (swapper_pg_dir - PAGE_OFFSET)@ha 4493: 450 mtcr r11 451 lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r10) /* Get level 1 entry */ 452 453 mtspr SPRN_MD_TWC, r11 454 mfspr r10, SPRN_MD_TWC 455 lwz r10, 0(r10) /* Get the pte */ 456 457 /* Insert the Guarded flag into the TWC from the Linux PTE. 458 * It is bit 27 of both the Linux PTE and the TWC (at least 459 * I got that right :-). It will be better when we can put 460 * this into the Linux pgd/pmd and load it in the operation 461 * above. 462 */ 463 rlwimi r11, r10, 0, _PAGE_GUARDED 464 mtspr SPRN_MD_TWC, r11 465 466 /* Both _PAGE_ACCESSED and _PAGE_PRESENT has to be set. 467 * We also need to know if the insn is a load/store, so: 468 * Clear _PAGE_PRESENT and load that which will 469 * trap into DTLB Error with store bit set accordinly. 470 */ 471 /* PRESENT=0x1, ACCESSED=0x20 472 * r11 = ((r10 & PRESENT) & ((r10 & ACCESSED) >> 5)); 473 * r10 = (r10 & ~PRESENT) | r11; 474 */ 475#ifdef CONFIG_SWAP 476 rlwinm r11, r10, 32-5, _PAGE_PRESENT 477 and r11, r11, r10 478 rlwimi r10, r11, 0, _PAGE_PRESENT 479#endif 480 /* The Linux PTE won't go exactly into the MMU TLB. 481 * Software indicator bits 24, 25, 26, and 27 must be 482 * set. All other Linux PTE bits control the behavior 483 * of the MMU. 484 */ 485 li r11, RPN_PATTERN 486 rlwimi r10, r11, 0, 24, 27 /* Set 24-27 */ 487 mtspr SPRN_MD_RPN, r10 /* Update TLB entry */ 488 489 /* Restore registers */ 490 mtspr SPRN_DAR, r11 /* Tag DAR */ 491 4920: mfspr r10, SPRN_SPRG_SCRATCH0 493 mfspr r11, SPRN_SPRG_SCRATCH1 494 rfi 495 patch_site 0b, patch__dtlbmiss_exit_1 496 497#ifdef CONFIG_PERF_EVENTS 498 patch_site 0f, patch__dtlbmiss_perf 4990: lwz r10, (dtlb_miss_counter - PAGE_OFFSET)@l(0) 500 addi r10, r10, 1 501 stw r10, (dtlb_miss_counter - PAGE_OFFSET)@l(0) 502 mfspr r10, SPRN_SPRG_SCRATCH0 503 mfspr r11, SPRN_SPRG_SCRATCH1 504 rfi 505#endif 506 507DTLBMissIMMR: 508 mtcr r11 509 /* Set 512k byte guarded page and mark it valid */ 510 li r10, MD_PS512K | MD_GUARDED | MD_SVALID 511 mtspr SPRN_MD_TWC, r10 512 mfspr r10, SPRN_IMMR /* Get current IMMR */ 513 rlwinm r10, r10, 0, 0xfff80000 /* Get 512 kbytes boundary */ 514 ori r10, r10, 0xf0 | MD_SPS16K | _PAGE_SH | _PAGE_DIRTY | \ 515 _PAGE_PRESENT | _PAGE_NO_CACHE 516 mtspr SPRN_MD_RPN, r10 /* Update TLB entry */ 517 518 li r11, RPN_PATTERN 519 mtspr SPRN_DAR, r11 /* Tag DAR */ 520 5210: mfspr r10, SPRN_SPRG_SCRATCH0 522 mfspr r11, SPRN_SPRG_SCRATCH1 523 rfi 524 patch_site 0b, patch__dtlbmiss_exit_2 525 526DTLBMissLinear: 527 mtcr r11 528 /* Set 8M byte page and mark it valid */ 529 li r11, MD_PS8MEG | MD_SVALID 530 mtspr SPRN_MD_TWC, r11 531 rlwinm r10, r10, 20, 0x0f800000 /* 8xx supports max 256Mb RAM */ 532 ori r10, r10, 0xf0 | MD_SPS16K | _PAGE_SH | _PAGE_DIRTY | \ 533 _PAGE_PRESENT 534 mtspr SPRN_MD_RPN, r10 /* Update TLB entry */ 535 536 li r11, RPN_PATTERN 537 mtspr SPRN_DAR, r11 /* Tag DAR */ 538 5390: mfspr r10, SPRN_SPRG_SCRATCH0 540 mfspr r11, SPRN_SPRG_SCRATCH1 541 rfi 542 patch_site 0b, patch__dtlbmiss_exit_3 543 544/* This is an instruction TLB error on the MPC8xx. This could be due 545 * to many reasons, such as executing guarded memory or illegal instruction 546 * addresses. There is nothing to do but handle a big time error fault. 547 */ 548 . = 0x1300 549InstructionTLBError: 550 EXCEPTION_PROLOG 551 mr r4,r12 552 andis. r5,r9,DSISR_SRR1_MATCH_32S@h /* Filter relevant SRR1 bits */ 553 andis. r10,r9,SRR1_ISI_NOPT@h 554 beq+ 1f 555 tlbie r4 556itlbie: 557 /* 0x400 is InstructionAccess exception, needed by bad_page_fault() */ 5581: EXC_XFER_LITE(0x400, handle_page_fault) 559 560/* This is the data TLB error on the MPC8xx. This could be due to 561 * many reasons, including a dirty update to a pte. We bail out to 562 * a higher level function that can handle it. 563 */ 564 . = 0x1400 565DataTLBError: 566 mtspr SPRN_SPRG_SCRATCH0, r10 567 mtspr SPRN_SPRG_SCRATCH1, r11 568 mfcr r10 569 570 mfspr r11, SPRN_DAR 571 cmpwi cr0, r11, RPN_PATTERN 572 beq- FixupDAR /* must be a buggy dcbX, icbi insn. */ 573DARFixed:/* Return from dcbx instruction bug workaround */ 574 EXCEPTION_PROLOG_1 575 EXCEPTION_PROLOG_2 576 mfspr r5,SPRN_DSISR 577 stw r5,_DSISR(r11) 578 mfspr r4,SPRN_DAR 579 andis. r10,r5,DSISR_NOHPTE@h 580 beq+ 1f 581 tlbie r4 582dtlbie: 5831: li r10,RPN_PATTERN 584 mtspr SPRN_DAR,r10 /* Tag DAR, to be used in DTLB Error */ 585 /* 0x300 is DataAccess exception, needed by bad_page_fault() */ 586 EXC_XFER_LITE(0x300, handle_page_fault) 587 588 EXCEPTION(0x1500, Trap_15, unknown_exception, EXC_XFER_EE) 589 EXCEPTION(0x1600, Trap_16, unknown_exception, EXC_XFER_EE) 590 EXCEPTION(0x1700, Trap_17, unknown_exception, EXC_XFER_EE) 591 EXCEPTION(0x1800, Trap_18, unknown_exception, EXC_XFER_EE) 592 EXCEPTION(0x1900, Trap_19, unknown_exception, EXC_XFER_EE) 593 EXCEPTION(0x1a00, Trap_1a, unknown_exception, EXC_XFER_EE) 594 EXCEPTION(0x1b00, Trap_1b, unknown_exception, EXC_XFER_EE) 595 596/* On the MPC8xx, these next four traps are used for development 597 * support of breakpoints and such. Someday I will get around to 598 * using them. 599 */ 600 . = 0x1c00 601DataBreakpoint: 602 mtspr SPRN_SPRG_SCRATCH0, r10 603 mtspr SPRN_SPRG_SCRATCH1, r11 604 mfcr r10 605 mfspr r11, SPRN_SRR0 606 cmplwi cr0, r11, (dtlbie - PAGE_OFFSET)@l 607 cmplwi cr7, r11, (itlbie - PAGE_OFFSET)@l 608 beq- cr0, 11f 609 beq- cr7, 11f 610 EXCEPTION_PROLOG_1 611 EXCEPTION_PROLOG_2 612 addi r3,r1,STACK_FRAME_OVERHEAD 613 mfspr r4,SPRN_BAR 614 stw r4,_DAR(r11) 615 mfspr r5,SPRN_DSISR 616 EXC_XFER_EE(0x1c00, do_break) 61711: 618 mtcr r10 619 mfspr r10, SPRN_SPRG_SCRATCH0 620 mfspr r11, SPRN_SPRG_SCRATCH1 621 rfi 622 623#ifdef CONFIG_PERF_EVENTS 624 . = 0x1d00 625InstructionBreakpoint: 626 mtspr SPRN_SPRG_SCRATCH0, r10 627 lwz r10, (instruction_counter - PAGE_OFFSET)@l(0) 628 addi r10, r10, -1 629 stw r10, (instruction_counter - PAGE_OFFSET)@l(0) 630 lis r10, 0xffff 631 ori r10, r10, 0x01 632 mtspr SPRN_COUNTA, r10 633 mfspr r10, SPRN_SPRG_SCRATCH0 634 rfi 635#else 636 EXCEPTION(0x1d00, Trap_1d, unknown_exception, EXC_XFER_EE) 637#endif 638 EXCEPTION(0x1e00, Trap_1e, unknown_exception, EXC_XFER_EE) 639 EXCEPTION(0x1f00, Trap_1f, unknown_exception, EXC_XFER_EE) 640 641 . = 0x2000 642 643/* This is the procedure to calculate the data EA for buggy dcbx,dcbi instructions 644 * by decoding the registers used by the dcbx instruction and adding them. 645 * DAR is set to the calculated address. 646 */ 647 /* define if you don't want to use self modifying code */ 648#define NO_SELF_MODIFYING_CODE 649FixupDAR:/* Entry point for dcbx workaround. */ 650 mtspr SPRN_M_TW, r10 651 /* fetch instruction from memory. */ 652 mfspr r10, SPRN_SRR0 653 mtspr SPRN_MD_EPN, r10 654 rlwinm r11, r10, 16, 0xfff8 655 cmpli cr0, r11, PAGE_OFFSET@h 656 mfspr r11, SPRN_M_TWB /* Get level 1 table */ 657 blt+ 3f 658 rlwinm r11, r10, 16, 0xfff8 659 6600: cmpli cr7, r11, (PAGE_OFFSET + 0x1800000)@h 661 patch_site 0b, patch__fixupdar_linmem_top 662 663 /* create physical page address from effective address */ 664 tophys(r11, r10) 665 blt- cr7, 201f 666 mfspr r11, SPRN_M_TWB /* Get level 1 table */ 667 rlwinm r11, r11, 0, 20, 31 668 oris r11, r11, (swapper_pg_dir - PAGE_OFFSET)@ha 6693: 670 lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r11) /* Get the level 1 entry */ 671 mtspr SPRN_MD_TWC, r11 672 mtcr r11 673 mfspr r11, SPRN_MD_TWC 674 lwz r11, 0(r11) /* Get the pte */ 675 bt 28,200f /* bit 28 = Large page (8M) */ 676 bt 29,202f /* bit 29 = Large page (8M or 512K) */ 677 /* concat physical page address(r11) and page offset(r10) */ 678 rlwimi r11, r10, 0, 32 - PAGE_SHIFT, 31 679201: lwz r11,0(r11) 680/* Check if it really is a dcbx instruction. */ 681/* dcbt and dcbtst does not generate DTLB Misses/Errors, 682 * no need to include them here */ 683 xoris r10, r11, 0x7c00 /* check if major OP code is 31 */ 684 rlwinm r10, r10, 0, 21, 5 685 cmpwi cr0, r10, 2028 /* Is dcbz? */ 686 beq+ 142f 687 cmpwi cr0, r10, 940 /* Is dcbi? */ 688 beq+ 142f 689 cmpwi cr0, r10, 108 /* Is dcbst? */ 690 beq+ 144f /* Fix up store bit! */ 691 cmpwi cr0, r10, 172 /* Is dcbf? */ 692 beq+ 142f 693 cmpwi cr0, r10, 1964 /* Is icbi? */ 694 beq+ 142f 695141: mfspr r10,SPRN_M_TW 696 b DARFixed /* Nope, go back to normal TLB processing */ 697 698200: 699 /* concat physical page address(r11) and page offset(r10) */ 700 rlwimi r11, r10, 0, 32 - PAGE_SHIFT_8M, 31 701 b 201b 702 703202: 704 /* concat physical page address(r11) and page offset(r10) */ 705 rlwimi r11, r10, 0, 32 - PAGE_SHIFT_512K, 31 706 b 201b 707 708144: mfspr r10, SPRN_DSISR 709 rlwinm r10, r10,0,7,5 /* Clear store bit for buggy dcbst insn */ 710 mtspr SPRN_DSISR, r10 711142: /* continue, it was a dcbx, dcbi instruction. */ 712#ifndef NO_SELF_MODIFYING_CODE 713 andis. r10,r11,0x1f /* test if reg RA is r0 */ 714 li r10,modified_instr@l 715 dcbtst r0,r10 /* touch for store */ 716 rlwinm r11,r11,0,0,20 /* Zero lower 10 bits */ 717 oris r11,r11,640 /* Transform instr. to a "add r10,RA,RB" */ 718 ori r11,r11,532 719 stw r11,0(r10) /* store add/and instruction */ 720 dcbf 0,r10 /* flush new instr. to memory. */ 721 icbi 0,r10 /* invalidate instr. cache line */ 722 mfspr r11, SPRN_SPRG_SCRATCH1 /* restore r11 */ 723 mfspr r10, SPRN_SPRG_SCRATCH0 /* restore r10 */ 724 isync /* Wait until new instr is loaded from memory */ 725modified_instr: 726 .space 4 /* this is where the add instr. is stored */ 727 bne+ 143f 728 subf r10,r0,r10 /* r10=r10-r0, only if reg RA is r0 */ 729143: mtdar r10 /* store faulting EA in DAR */ 730 mfspr r10,SPRN_M_TW 731 b DARFixed /* Go back to normal TLB handling */ 732#else 733 mfctr r10 734 mtdar r10 /* save ctr reg in DAR */ 735 rlwinm r10, r11, 24, 24, 28 /* offset into jump table for reg RB */ 736 addi r10, r10, 150f@l /* add start of table */ 737 mtctr r10 /* load ctr with jump address */ 738 xor r10, r10, r10 /* sum starts at zero */ 739 bctr /* jump into table */ 740150: 741 add r10, r10, r0 ;b 151f 742 add r10, r10, r1 ;b 151f 743 add r10, r10, r2 ;b 151f 744 add r10, r10, r3 ;b 151f 745 add r10, r10, r4 ;b 151f 746 add r10, r10, r5 ;b 151f 747 add r10, r10, r6 ;b 151f 748 add r10, r10, r7 ;b 151f 749 add r10, r10, r8 ;b 151f 750 add r10, r10, r9 ;b 151f 751 mtctr r11 ;b 154f /* r10 needs special handling */ 752 mtctr r11 ;b 153f /* r11 needs special handling */ 753 add r10, r10, r12 ;b 151f 754 add r10, r10, r13 ;b 151f 755 add r10, r10, r14 ;b 151f 756 add r10, r10, r15 ;b 151f 757 add r10, r10, r16 ;b 151f 758 add r10, r10, r17 ;b 151f 759 add r10, r10, r18 ;b 151f 760 add r10, r10, r19 ;b 151f 761 add r10, r10, r20 ;b 151f 762 add r10, r10, r21 ;b 151f 763 add r10, r10, r22 ;b 151f 764 add r10, r10, r23 ;b 151f 765 add r10, r10, r24 ;b 151f 766 add r10, r10, r25 ;b 151f 767 add r10, r10, r26 ;b 151f 768 add r10, r10, r27 ;b 151f 769 add r10, r10, r28 ;b 151f 770 add r10, r10, r29 ;b 151f 771 add r10, r10, r30 ;b 151f 772 add r10, r10, r31 773151: 774 rlwinm. r11,r11,19,24,28 /* offset into jump table for reg RA */ 775 beq 152f /* if reg RA is zero, don't add it */ 776 addi r11, r11, 150b@l /* add start of table */ 777 mtctr r11 /* load ctr with jump address */ 778 rlwinm r11,r11,0,16,10 /* make sure we don't execute this more than once */ 779 bctr /* jump into table */ 780152: 781 mfdar r11 782 mtctr r11 /* restore ctr reg from DAR */ 783 mtdar r10 /* save fault EA to DAR */ 784 mfspr r10,SPRN_M_TW 785 b DARFixed /* Go back to normal TLB handling */ 786 787 /* special handling for r10,r11 since these are modified already */ 788153: mfspr r11, SPRN_SPRG_SCRATCH1 /* load r11 from SPRN_SPRG_SCRATCH1 */ 789 add r10, r10, r11 /* add it */ 790 mfctr r11 /* restore r11 */ 791 b 151b 792154: mfspr r11, SPRN_SPRG_SCRATCH0 /* load r10 from SPRN_SPRG_SCRATCH0 */ 793 add r10, r10, r11 /* add it */ 794 mfctr r11 /* restore r11 */ 795 b 151b 796#endif 797 798/* 799 * This is where the main kernel code starts. 800 */ 801start_here: 802 /* ptr to current */ 803 lis r2,init_task@h 804 ori r2,r2,init_task@l 805 806 /* ptr to phys current thread */ 807 tophys(r4,r2) 808 addi r4,r4,THREAD /* init task's THREAD */ 809 mtspr SPRN_SPRG_THREAD,r4 810 811 /* stack */ 812 lis r1,init_thread_union@ha 813 addi r1,r1,init_thread_union@l 814 li r0,0 815 stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1) 816 817 lis r6, swapper_pg_dir@ha 818 tophys(r6,r6) 819 mtspr SPRN_M_TWB, r6 820 821 bl early_init /* We have to do this with MMU on */ 822 823/* 824 * Decide what sort of machine this is and initialize the MMU. 825 */ 826 li r3,0 827 mr r4,r31 828 bl machine_init 829 bl MMU_init 830 831/* 832 * Go back to running unmapped so we can load up new values 833 * and change to using our exception vectors. 834 * On the 8xx, all we have to do is invalidate the TLB to clear 835 * the old 8M byte TLB mappings and load the page table base register. 836 */ 837 /* The right way to do this would be to track it down through 838 * init's THREAD like the context switch code does, but this is 839 * easier......until someone changes init's static structures. 840 */ 841 lis r4,2f@h 842 ori r4,r4,2f@l 843 tophys(r4,r4) 844 li r3,MSR_KERNEL & ~(MSR_IR|MSR_DR) 845 mtspr SPRN_SRR0,r4 846 mtspr SPRN_SRR1,r3 847 rfi 848/* Load up the kernel context */ 8492: 850 tlbia /* Clear all TLB entries */ 851 sync /* wait for tlbia/tlbie to finish */ 852 853 /* set up the PTE pointers for the Abatron bdiGDB. 854 */ 855 tovirt(r6,r6) 856 lis r5, abatron_pteptrs@h 857 ori r5, r5, abatron_pteptrs@l 858 stw r5, 0xf0(0) /* Must match your Abatron config file */ 859 tophys(r5,r5) 860 stw r6, 0(r5) 861 862/* Now turn on the MMU for real! */ 863 li r4,MSR_KERNEL 864 lis r3,start_kernel@h 865 ori r3,r3,start_kernel@l 866 mtspr SPRN_SRR0,r3 867 mtspr SPRN_SRR1,r4 868 rfi /* enable MMU and jump to start_kernel */ 869 870/* Set up the initial MMU state so we can do the first level of 871 * kernel initialization. This maps the first 8 MBytes of memory 1:1 872 * virtual to physical. Also, set the cache mode since that is defined 873 * by TLB entries and perform any additional mapping (like of the IMMR). 874 * If configured to pin some TLBs, we pin the first 8 Mbytes of kernel, 875 * 24 Mbytes of data, and the 512k IMMR space. Anything not covered by 876 * these mappings is mapped by page tables. 877 */ 878initial_mmu: 879 li r8, 0 880 mtspr SPRN_MI_CTR, r8 /* remove PINNED ITLB entries */ 881 lis r10, MD_RESETVAL@h 882#ifndef CONFIG_8xx_COPYBACK 883 oris r10, r10, MD_WTDEF@h 884#endif 885 mtspr SPRN_MD_CTR, r10 /* remove PINNED DTLB entries */ 886 887 tlbia /* Invalidate all TLB entries */ 888#ifdef CONFIG_PIN_TLB_TEXT 889 lis r8, MI_RSV4I@h 890 ori r8, r8, 0x1c00 891 892 mtspr SPRN_MI_CTR, r8 /* Set instruction MMU control */ 893#endif 894 895#ifdef CONFIG_PIN_TLB_DATA 896 oris r10, r10, MD_RSV4I@h 897 mtspr SPRN_MD_CTR, r10 /* Set data TLB control */ 898#endif 899 900 /* Now map the lower 8 Meg into the ITLB. */ 901 lis r8, KERNELBASE@h /* Create vaddr for TLB */ 902 ori r8, r8, MI_EVALID /* Mark it valid */ 903 mtspr SPRN_MI_EPN, r8 904 li r8, MI_PS8MEG /* Set 8M byte page */ 905 ori r8, r8, MI_SVALID /* Make it valid */ 906 mtspr SPRN_MI_TWC, r8 907 li r8, MI_BOOTINIT /* Create RPN for address 0 */ 908 mtspr SPRN_MI_RPN, r8 /* Store TLB entry */ 909 910 lis r8, MI_APG_INIT@h /* Set protection modes */ 911 ori r8, r8, MI_APG_INIT@l 912 mtspr SPRN_MI_AP, r8 913 lis r8, MD_APG_INIT@h 914 ori r8, r8, MD_APG_INIT@l 915 mtspr SPRN_MD_AP, r8 916 917 /* Map a 512k page for the IMMR to get the processor 918 * internal registers (among other things). 919 */ 920#ifdef CONFIG_PIN_TLB_IMMR 921 oris r10, r10, MD_RSV4I@h 922 ori r10, r10, 0x1c00 923 mtspr SPRN_MD_CTR, r10 924 925 mfspr r9, 638 /* Get current IMMR */ 926 andis. r9, r9, 0xfff8 /* Get 512 kbytes boundary */ 927 928 lis r8, VIRT_IMMR_BASE@h /* Create vaddr for TLB */ 929 ori r8, r8, MD_EVALID /* Mark it valid */ 930 mtspr SPRN_MD_EPN, r8 931 li r8, MD_PS512K | MD_GUARDED /* Set 512k byte page */ 932 ori r8, r8, MD_SVALID /* Make it valid */ 933 mtspr SPRN_MD_TWC, r8 934 mr r8, r9 /* Create paddr for TLB */ 935 ori r8, r8, MI_BOOTINIT|0x2 /* Inhibit cache -- Cort */ 936 mtspr SPRN_MD_RPN, r8 937#endif 938 939 /* Since the cache is enabled according to the information we 940 * just loaded into the TLB, invalidate and enable the caches here. 941 * We should probably check/set other modes....later. 942 */ 943 lis r8, IDC_INVALL@h 944 mtspr SPRN_IC_CST, r8 945 mtspr SPRN_DC_CST, r8 946 lis r8, IDC_ENABLE@h 947 mtspr SPRN_IC_CST, r8 948#ifdef CONFIG_8xx_COPYBACK 949 mtspr SPRN_DC_CST, r8 950#else 951 /* For a debug option, I left this here to easily enable 952 * the write through cache mode 953 */ 954 lis r8, DC_SFWT@h 955 mtspr SPRN_DC_CST, r8 956 lis r8, IDC_ENABLE@h 957 mtspr SPRN_DC_CST, r8 958#endif 959 /* Disable debug mode entry on breakpoints */ 960 mfspr r8, SPRN_DER 961#ifdef CONFIG_PERF_EVENTS 962 rlwinm r8, r8, 0, ~0xc 963#else 964 rlwinm r8, r8, 0, ~0x8 965#endif 966 mtspr SPRN_DER, r8 967 blr 968 969 970/* 971 * We put a few things here that have to be page-aligned. 972 * This stuff goes at the beginning of the data segment, 973 * which is page-aligned. 974 */ 975 .data 976 .globl sdata 977sdata: 978 .globl empty_zero_page 979 .align PAGE_SHIFT 980empty_zero_page: 981 .space PAGE_SIZE 982EXPORT_SYMBOL(empty_zero_page) 983 984 .globl swapper_pg_dir 985swapper_pg_dir: 986 .space PGD_TABLE_SIZE 987 988/* Room for two PTE table poiners, usually the kernel and current user 989 * pointer to their respective root page table (pgdir). 990 */ 991abatron_pteptrs: 992 .space 8 993