1/* SPDX-License-Identifier: GPL-2.0-or-later */ 2/* 3 * PowerPC version 4 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 5 * Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP 6 * Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu> 7 * Low-level exception handlers and MMU support 8 * rewritten by Paul Mackerras. 9 * Copyright (C) 1996 Paul Mackerras. 10 * MPC8xx modifications by Dan Malek 11 * Copyright (C) 1997 Dan Malek (dmalek@jlc.net). 12 * 13 * This file contains low-level support and setup for PowerPC 8xx 14 * embedded processors, including trap and interrupt dispatch. 15 */ 16 17#include <linux/init.h> 18#include <linux/magic.h> 19#include <linux/pgtable.h> 20#include <linux/sizes.h> 21#include <linux/linkage.h> 22 23#include <asm/processor.h> 24#include <asm/page.h> 25#include <asm/mmu.h> 26#include <asm/cache.h> 27#include <asm/cputable.h> 28#include <asm/thread_info.h> 29#include <asm/ppc_asm.h> 30#include <asm/asm-offsets.h> 31#include <asm/ptrace.h> 32#include <asm/code-patching-asm.h> 33#include <asm/interrupt.h> 34 35/* 36 * Value for the bits that have fixed value in RPN entries. 37 * Also used for tagging DAR for DTLBerror. 38 */ 39#define RPN_PATTERN 0x00f0 40 41#include "head_32.h" 42 43#define PAGE_SHIFT_512K 19 44#define PAGE_SHIFT_8M 23 45 46 __HEAD 47_GLOBAL(_stext); 48_GLOBAL(_start); 49 50/* MPC8xx 51 * This port was done on an MBX board with an 860. Right now I only 52 * support an ELF compressed (zImage) boot from EPPC-Bug because the 53 * code there loads up some registers before calling us: 54 * r3: ptr to board info data 55 * r4: initrd_start or if no initrd then 0 56 * r5: initrd_end - unused if r4 is 0 57 * r6: Start of command line string 58 * r7: End of command line string 59 * 60 * I decided to use conditional compilation instead of checking PVR and 61 * adding more processor specific branches around code I don't need. 62 * Since this is an embedded processor, I also appreciate any memory 63 * savings I can get. 64 * 65 * The MPC8xx does not have any BATs, but it supports large page sizes. 66 * We first initialize the MMU to support 8M byte pages, then load one 67 * entry into each of the instruction and data TLBs to map the first 68 * 8M 1:1. I also mapped an additional I/O space 1:1 so we can get to 69 * the "internal" processor registers before MMU_init is called. 70 * 71 * -- Dan 72 */ 73 .globl __start 74__start: 75 mr r31,r3 /* save device tree ptr */ 76 77 /* We have to turn on the MMU right away so we get cache modes 78 * set correctly. 79 */ 80 bl initial_mmu 81 82/* We now have the lower 8 Meg mapped into TLB entries, and the caches 83 * ready to work. 84 */ 85 86turn_on_mmu: 87 mfmsr r0 88 ori r0,r0,MSR_DR|MSR_IR 89 mtspr SPRN_SRR1,r0 90 lis r0,start_here@h 91 ori r0,r0,start_here@l 92 mtspr SPRN_SRR0,r0 93 rfi /* enables MMU */ 94 95 96#ifdef CONFIG_PERF_EVENTS 97 .align 4 98 99 .globl itlb_miss_counter 100itlb_miss_counter: 101 .space 4 102 103 .globl dtlb_miss_counter 104dtlb_miss_counter: 105 .space 4 106 107 .globl instruction_counter 108instruction_counter: 109 .space 4 110#endif 111 112/* System reset */ 113 EXCEPTION(INTERRUPT_SYSTEM_RESET, Reset, system_reset_exception) 114 115/* Machine check */ 116 START_EXCEPTION(INTERRUPT_MACHINE_CHECK, MachineCheck) 117 EXCEPTION_PROLOG INTERRUPT_MACHINE_CHECK MachineCheck handle_dar_dsisr=1 118 prepare_transfer_to_handler 119 bl machine_check_exception 120 b interrupt_return 121 122/* External interrupt */ 123 EXCEPTION(INTERRUPT_EXTERNAL, HardwareInterrupt, do_IRQ) 124 125/* Alignment exception */ 126 START_EXCEPTION(INTERRUPT_ALIGNMENT, Alignment) 127 EXCEPTION_PROLOG INTERRUPT_ALIGNMENT Alignment handle_dar_dsisr=1 128 prepare_transfer_to_handler 129 bl alignment_exception 130 REST_NVGPRS(r1) 131 b interrupt_return 132 133/* Program check exception */ 134 START_EXCEPTION(INTERRUPT_PROGRAM, ProgramCheck) 135 EXCEPTION_PROLOG INTERRUPT_PROGRAM ProgramCheck 136 prepare_transfer_to_handler 137 bl program_check_exception 138 REST_NVGPRS(r1) 139 b interrupt_return 140 141/* Decrementer */ 142 EXCEPTION(INTERRUPT_DECREMENTER, Decrementer, timer_interrupt) 143 144/* System call */ 145 START_EXCEPTION(INTERRUPT_SYSCALL, SystemCall) 146 SYSCALL_ENTRY INTERRUPT_SYSCALL 147 148/* Single step - not used on 601 */ 149 EXCEPTION(INTERRUPT_TRACE, SingleStep, single_step_exception) 150 151/* On the MPC8xx, this is a software emulation interrupt. It occurs 152 * for all unimplemented and illegal instructions. 153 */ 154 START_EXCEPTION(INTERRUPT_SOFT_EMU_8xx, SoftEmu) 155 EXCEPTION_PROLOG INTERRUPT_SOFT_EMU_8xx SoftEmu 156 prepare_transfer_to_handler 157 bl emulation_assist_interrupt 158 REST_NVGPRS(r1) 159 b interrupt_return 160 161/* 162 * For the MPC8xx, this is a software tablewalk to load the instruction 163 * TLB. The task switch loads the M_TWB register with the pointer to the first 164 * level table. 165 * If we discover there is no second level table (value is zero) or if there 166 * is an invalid pte, we load that into the TLB, which causes another fault 167 * into the TLB Error interrupt where we can handle such problems. 168 * We have to use the MD_xxx registers for the tablewalk because the 169 * equivalent MI_xxx registers only perform the attribute functions. 170 */ 171 172#ifdef CONFIG_8xx_CPU15 173#define INVALIDATE_ADJACENT_PAGES_CPU15(addr, tmp) \ 174 addi tmp, addr, PAGE_SIZE; \ 175 tlbie tmp; \ 176 addi tmp, addr, -PAGE_SIZE; \ 177 tlbie tmp 178#else 179#define INVALIDATE_ADJACENT_PAGES_CPU15(addr, tmp) 180#endif 181 182 START_EXCEPTION(INTERRUPT_INST_TLB_MISS_8xx, InstructionTLBMiss) 183 mtspr SPRN_SPRG_SCRATCH2, r10 184 mtspr SPRN_M_TW, r11 185 186 /* If we are faulting a kernel address, we have to use the 187 * kernel page tables. 188 */ 189 mfspr r10, SPRN_SRR0 /* Get effective address of fault */ 190 INVALIDATE_ADJACENT_PAGES_CPU15(r10, r11) 191 mtspr SPRN_MD_EPN, r10 192 mfspr r10, SPRN_M_TWB /* Get level 1 table */ 193 lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r10) /* Get level 1 entry */ 194 mtspr SPRN_MD_TWC, r11 195 mfspr r10, SPRN_MD_TWC 196 lwz r10, 0(r10) /* Get the pte */ 197 rlwimi r11, r10, 0, _PAGE_GUARDED | _PAGE_ACCESSED 198 rlwimi r11, r10, 32 - 9, _PMD_PAGE_512K 199 mtspr SPRN_MI_TWC, r11 200 /* The Linux PTE won't go exactly into the MMU TLB. 201 * Software indicator bits 20 and 23 must be clear. 202 * Software indicator bits 22, 24, 25, 26, and 27 must be 203 * set. All other Linux PTE bits control the behavior 204 * of the MMU. 205 */ 206 rlwinm r10, r10, 0, ~0x0f00 /* Clear bits 20-23 */ 207 rlwimi r10, r10, 4, 0x0400 /* Copy _PAGE_EXEC into bit 21 */ 208 ori r10, r10, RPN_PATTERN | 0x200 /* Set 22 and 24-27 */ 209 mtspr SPRN_MI_RPN, r10 /* Update TLB entry */ 210 211 /* Restore registers */ 2120: mfspr r10, SPRN_SPRG_SCRATCH2 213 mfspr r11, SPRN_M_TW 214 rfi 215 patch_site 0b, patch__itlbmiss_exit_1 216 217#ifdef CONFIG_PERF_EVENTS 218 patch_site 0f, patch__itlbmiss_perf 2190: lwz r10, (itlb_miss_counter - PAGE_OFFSET)@l(0) 220 addi r10, r10, 1 221 stw r10, (itlb_miss_counter - PAGE_OFFSET)@l(0) 222 mfspr r10, SPRN_SPRG_SCRATCH2 223 mfspr r11, SPRN_M_TW 224 rfi 225#endif 226 227 START_EXCEPTION(INTERRUPT_DATA_TLB_MISS_8xx, DataStoreTLBMiss) 228 mtspr SPRN_SPRG_SCRATCH2, r10 229 mtspr SPRN_M_TW, r11 230 231 /* If we are faulting a kernel address, we have to use the 232 * kernel page tables. 233 */ 234 mfspr r10, SPRN_MD_EPN 235 mfspr r10, SPRN_M_TWB /* Get level 1 table */ 236 lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r10) /* Get level 1 entry */ 237 238 mtspr SPRN_MD_TWC, r11 239 mfspr r10, SPRN_MD_TWC 240 lwz r10, 0(r10) /* Get the pte */ 241 242 /* Insert Guarded and Accessed flags into the TWC from the Linux PTE. 243 * It is bit 27 of both the Linux PTE and the TWC (at least 244 * I got that right :-). It will be better when we can put 245 * this into the Linux pgd/pmd and load it in the operation 246 * above. 247 */ 248 rlwimi r11, r10, 0, _PAGE_GUARDED | _PAGE_ACCESSED 249 rlwimi r11, r10, 32 - 9, _PMD_PAGE_512K 250 mtspr SPRN_MD_TWC, r11 251 252 /* The Linux PTE won't go exactly into the MMU TLB. 253 * Software indicator bits 24, 25, 26, and 27 must be 254 * set. All other Linux PTE bits control the behavior 255 * of the MMU. 256 */ 257 li r11, RPN_PATTERN 258 rlwimi r10, r11, 0, 24, 27 /* Set 24-27 */ 259 mtspr SPRN_MD_RPN, r10 /* Update TLB entry */ 260 mtspr SPRN_DAR, r11 /* Tag DAR */ 261 262 /* Restore registers */ 263 2640: mfspr r10, SPRN_SPRG_SCRATCH2 265 mfspr r11, SPRN_M_TW 266 rfi 267 patch_site 0b, patch__dtlbmiss_exit_1 268 269#ifdef CONFIG_PERF_EVENTS 270 patch_site 0f, patch__dtlbmiss_perf 2710: lwz r10, (dtlb_miss_counter - PAGE_OFFSET)@l(0) 272 addi r10, r10, 1 273 stw r10, (dtlb_miss_counter - PAGE_OFFSET)@l(0) 274 mfspr r10, SPRN_SPRG_SCRATCH2 275 mfspr r11, SPRN_M_TW 276 rfi 277#endif 278 279/* This is an instruction TLB error on the MPC8xx. This could be due 280 * to many reasons, such as executing guarded memory or illegal instruction 281 * addresses. There is nothing to do but handle a big time error fault. 282 */ 283 START_EXCEPTION(INTERRUPT_INST_TLB_ERROR_8xx, InstructionTLBError) 284 /* 0x400 is InstructionAccess exception, needed by bad_page_fault() */ 285 EXCEPTION_PROLOG INTERRUPT_INST_STORAGE InstructionTLBError 286 andis. r5,r9,DSISR_SRR1_MATCH_32S@h /* Filter relevant SRR1 bits */ 287 andis. r10,r9,SRR1_ISI_NOPT@h 288 beq+ .Litlbie 289 tlbie r12 290.Litlbie: 291 stw r12, _DAR(r11) 292 stw r5, _DSISR(r11) 293 prepare_transfer_to_handler 294 bl do_page_fault 295 b interrupt_return 296 297/* This is the data TLB error on the MPC8xx. This could be due to 298 * many reasons, including a dirty update to a pte. We bail out to 299 * a higher level function that can handle it. 300 */ 301 START_EXCEPTION(INTERRUPT_DATA_TLB_ERROR_8xx, DataTLBError) 302 EXCEPTION_PROLOG_0 handle_dar_dsisr=1 303 mfspr r11, SPRN_DAR 304 cmpwi cr1, r11, RPN_PATTERN 305 beq- cr1, FixupDAR /* must be a buggy dcbX, icbi insn. */ 306DARFixed:/* Return from dcbx instruction bug workaround */ 307 mfspr r11, SPRN_DSISR 308 rlwinm r11, r11, 0, DSISR_NOHPTE 309 cmpwi cr1, r11, 0 310 beq+ cr1, .Ldtlbie 311 mfspr r11, SPRN_DAR 312 tlbie r11 313 rlwinm r11, r11, 16, 0xffff 314 cmplwi cr1, r11, TASK_SIZE@h 315 bge- cr1, FixupPGD 316.Ldtlbie: 317 EXCEPTION_PROLOG_1 318 /* 0x300 is DataAccess exception, needed by bad_page_fault() */ 319 EXCEPTION_PROLOG_2 INTERRUPT_DATA_STORAGE DataTLBError handle_dar_dsisr=1 320 prepare_transfer_to_handler 321 bl do_page_fault 322 b interrupt_return 323 324#ifdef CONFIG_VMAP_STACK 325 vmap_stack_overflow_exception 326#endif 327 328/* On the MPC8xx, these next four traps are used for development 329 * support of breakpoints and such. Someday I will get around to 330 * using them. 331 */ 332 START_EXCEPTION(INTERRUPT_DATA_BREAKPOINT_8xx, DataBreakpoint) 333 EXCEPTION_PROLOG_0 handle_dar_dsisr=1 334 mfspr r11, SPRN_SRR0 335 cmplwi cr1, r11, (.Ldtlbie - PAGE_OFFSET)@l 336 cmplwi cr7, r11, (.Litlbie - PAGE_OFFSET)@l 337 cror 4*cr1+eq, 4*cr1+eq, 4*cr7+eq 338 bne cr1, 1f 339 mtcr r10 340 mfspr r10, SPRN_SPRG_SCRATCH0 341 mfspr r11, SPRN_SPRG_SCRATCH1 342 rfi 343 3441: EXCEPTION_PROLOG_1 345 EXCEPTION_PROLOG_2 INTERRUPT_DATA_BREAKPOINT_8xx DataBreakpoint handle_dar_dsisr=1 346 mfspr r4,SPRN_BAR 347 stw r4,_DAR(r11) 348 prepare_transfer_to_handler 349 bl do_break 350 REST_NVGPRS(r1) 351 b interrupt_return 352 353#ifdef CONFIG_PERF_EVENTS 354 START_EXCEPTION(INTERRUPT_INST_BREAKPOINT_8xx, InstructionBreakpoint) 355 mtspr SPRN_SPRG_SCRATCH0, r10 356 lwz r10, (instruction_counter - PAGE_OFFSET)@l(0) 357 addi r10, r10, -1 358 stw r10, (instruction_counter - PAGE_OFFSET)@l(0) 359 lis r10, 0xffff 360 ori r10, r10, 0x01 361 mtspr SPRN_COUNTA, r10 362 mfspr r10, SPRN_SPRG_SCRATCH0 363 rfi 364#else 365 EXCEPTION(INTERRUPT_INST_BREAKPOINT_8xx, Trap_1d, unknown_exception) 366#endif 367 EXCEPTION(0x1e00, Trap_1e, unknown_exception) 368 EXCEPTION(0x1f00, Trap_1f, unknown_exception) 369 370 __HEAD 371 . = 0x2000 372 373FixupPGD: 374 mtspr SPRN_M_TW, r10 375 mfspr r10, SPRN_DAR 376 mtspr SPRN_MD_EPN, r10 377 mfspr r11, SPRN_M_TWB /* Get level 1 table */ 378 lwz r10, (swapper_pg_dir - PAGE_OFFSET)@l(r11) /* Get the level 1 entry */ 379 cmpwi cr1, r10, 0 380 bne cr1, 1f 381 382 rlwinm r10, r11, 0, 20, 31 383 oris r10, r10, (swapper_pg_dir - PAGE_OFFSET)@ha 384 lwz r10, (swapper_pg_dir - PAGE_OFFSET)@l(r10) /* Get the level 1 entry */ 385 cmpwi cr1, r10, 0 386 beq cr1, 1f 387 stw r10, (swapper_pg_dir - PAGE_OFFSET)@l(r11) /* Set the level 1 entry */ 388 mfspr r10, SPRN_M_TW 389 mtcr r10 390 mfspr r10, SPRN_SPRG_SCRATCH0 391 mfspr r11, SPRN_SPRG_SCRATCH1 392 rfi 3931: 394 mfspr r10, SPRN_M_TW 395 b .Ldtlbie 396 397/* This is the procedure to calculate the data EA for buggy dcbx,dcbi instructions 398 * by decoding the registers used by the dcbx instruction and adding them. 399 * DAR is set to the calculated address. 400 */ 401FixupDAR:/* Entry point for dcbx workaround. */ 402 mtspr SPRN_M_TW, r10 403 /* fetch instruction from memory. */ 404 mfspr r10, SPRN_SRR0 405 mtspr SPRN_MD_EPN, r10 406 rlwinm r11, r10, 16, 0xfff8 407 cmpli cr1, r11, TASK_SIZE@h 408 mfspr r11, SPRN_M_TWB /* Get level 1 table */ 409 blt+ cr1, 3f 410 411 /* create physical page address from effective address */ 412 tophys(r11, r10) 413 mfspr r11, SPRN_M_TWB /* Get level 1 table */ 414 rlwinm r11, r11, 0, 20, 31 415 oris r11, r11, (swapper_pg_dir - PAGE_OFFSET)@ha 4163: 417 lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r11) /* Get the level 1 entry */ 418 rlwinm r11, r11, 0, ~_PMD_PAGE_8M 419 mtspr SPRN_MD_TWC, r11 420 mfspr r11, SPRN_MD_TWC 421 lwz r11, 0(r11) /* Get the pte */ 422 /* concat physical page address(r11) and page offset(r10) */ 423 rlwimi r11, r10, 0, 32 - PAGE_SHIFT, 31 424 lwz r11,0(r11) 425/* Check if it really is a dcbx instruction. */ 426/* dcbt and dcbtst does not generate DTLB Misses/Errors, 427 * no need to include them here */ 428 xoris r10, r11, 0x7c00 /* check if major OP code is 31 */ 429 rlwinm r10, r10, 0, 21, 5 430 cmpwi cr1, r10, 2028 /* Is dcbz? */ 431 beq+ cr1, 142f 432 cmpwi cr1, r10, 940 /* Is dcbi? */ 433 beq+ cr1, 142f 434 cmpwi cr1, r10, 108 /* Is dcbst? */ 435 beq+ cr1, 144f /* Fix up store bit! */ 436 cmpwi cr1, r10, 172 /* Is dcbf? */ 437 beq+ cr1, 142f 438 cmpwi cr1, r10, 1964 /* Is icbi? */ 439 beq+ cr1, 142f 440141: mfspr r10,SPRN_M_TW 441 b DARFixed /* Nope, go back to normal TLB processing */ 442 443144: mfspr r10, SPRN_DSISR 444 rlwinm r10, r10,0,7,5 /* Clear store bit for buggy dcbst insn */ 445 mtspr SPRN_DSISR, r10 446142: /* continue, it was a dcbx, dcbi instruction. */ 447 mfctr r10 448 mtdar r10 /* save ctr reg in DAR */ 449 rlwinm r10, r11, 24, 24, 28 /* offset into jump table for reg RB */ 450 addi r10, r10, 150f@l /* add start of table */ 451 mtctr r10 /* load ctr with jump address */ 452 xor r10, r10, r10 /* sum starts at zero */ 453 bctr /* jump into table */ 454150: 455 add r10, r10, r0 ;b 151f 456 add r10, r10, r1 ;b 151f 457 add r10, r10, r2 ;b 151f 458 add r10, r10, r3 ;b 151f 459 add r10, r10, r4 ;b 151f 460 add r10, r10, r5 ;b 151f 461 add r10, r10, r6 ;b 151f 462 add r10, r10, r7 ;b 151f 463 add r10, r10, r8 ;b 151f 464 add r10, r10, r9 ;b 151f 465 mtctr r11 ;b 154f /* r10 needs special handling */ 466 mtctr r11 ;b 153f /* r11 needs special handling */ 467 add r10, r10, r12 ;b 151f 468 add r10, r10, r13 ;b 151f 469 add r10, r10, r14 ;b 151f 470 add r10, r10, r15 ;b 151f 471 add r10, r10, r16 ;b 151f 472 add r10, r10, r17 ;b 151f 473 add r10, r10, r18 ;b 151f 474 add r10, r10, r19 ;b 151f 475 add r10, r10, r20 ;b 151f 476 add r10, r10, r21 ;b 151f 477 add r10, r10, r22 ;b 151f 478 add r10, r10, r23 ;b 151f 479 add r10, r10, r24 ;b 151f 480 add r10, r10, r25 ;b 151f 481 add r10, r10, r26 ;b 151f 482 add r10, r10, r27 ;b 151f 483 add r10, r10, r28 ;b 151f 484 add r10, r10, r29 ;b 151f 485 add r10, r10, r30 ;b 151f 486 add r10, r10, r31 487151: 488 rlwinm r11,r11,19,24,28 /* offset into jump table for reg RA */ 489 cmpwi cr1, r11, 0 490 beq cr1, 152f /* if reg RA is zero, don't add it */ 491 addi r11, r11, 150b@l /* add start of table */ 492 mtctr r11 /* load ctr with jump address */ 493 rlwinm r11,r11,0,16,10 /* make sure we don't execute this more than once */ 494 bctr /* jump into table */ 495152: 496 mfdar r11 497 mtctr r11 /* restore ctr reg from DAR */ 498 mfspr r11, SPRN_SPRG_THREAD 499 stw r10, DAR(r11) 500 mfspr r10, SPRN_DSISR 501 stw r10, DSISR(r11) 502 mfspr r10,SPRN_M_TW 503 b DARFixed /* Go back to normal TLB handling */ 504 505 /* special handling for r10,r11 since these are modified already */ 506153: mfspr r11, SPRN_SPRG_SCRATCH1 /* load r11 from SPRN_SPRG_SCRATCH1 */ 507 add r10, r10, r11 /* add it */ 508 mfctr r11 /* restore r11 */ 509 b 151b 510154: mfspr r11, SPRN_SPRG_SCRATCH0 /* load r10 from SPRN_SPRG_SCRATCH0 */ 511 add r10, r10, r11 /* add it */ 512 mfctr r11 /* restore r11 */ 513 b 151b 514 515/* 516 * This is where the main kernel code starts. 517 */ 518start_here: 519 /* ptr to current */ 520 lis r2,init_task@h 521 ori r2,r2,init_task@l 522 523 /* ptr to phys current thread */ 524 tophys(r4,r2) 525 addi r4,r4,THREAD /* init task's THREAD */ 526 mtspr SPRN_SPRG_THREAD,r4 527 528 /* stack */ 529 lis r1,init_thread_union@ha 530 addi r1,r1,init_thread_union@l 531 lis r0, STACK_END_MAGIC@h 532 ori r0, r0, STACK_END_MAGIC@l 533 stw r0, 0(r1) 534 li r0,0 535 stwu r0,THREAD_SIZE-STACK_FRAME_MIN_SIZE(r1) 536 537 lis r6, swapper_pg_dir@ha 538 tophys(r6,r6) 539 mtspr SPRN_M_TWB, r6 540 541 bl early_init /* We have to do this with MMU on */ 542 543/* 544 * Decide what sort of machine this is and initialize the MMU. 545 */ 546#ifdef CONFIG_KASAN 547 bl kasan_early_init 548#endif 549 li r3,0 550 mr r4,r31 551 bl machine_init 552 bl MMU_init 553 554/* 555 * Go back to running unmapped so we can load up new values 556 * and change to using our exception vectors. 557 * On the 8xx, all we have to do is invalidate the TLB to clear 558 * the old 8M byte TLB mappings and load the page table base register. 559 */ 560 /* The right way to do this would be to track it down through 561 * init's THREAD like the context switch code does, but this is 562 * easier......until someone changes init's static structures. 563 */ 564 lis r4,2f@h 565 ori r4,r4,2f@l 566 tophys(r4,r4) 567 li r3,MSR_KERNEL & ~(MSR_IR|MSR_DR) 568 mtspr SPRN_SRR0,r4 569 mtspr SPRN_SRR1,r3 570 rfi 571/* Load up the kernel context */ 5722: 573#ifdef CONFIG_PIN_TLB_IMMR 574 lis r0, MD_TWAM@h 575 oris r0, r0, 0x1f00 576 mtspr SPRN_MD_CTR, r0 577 LOAD_REG_IMMEDIATE(r0, VIRT_IMMR_BASE | MD_EVALID) 578 tlbie r0 579 mtspr SPRN_MD_EPN, r0 580 LOAD_REG_IMMEDIATE(r0, MD_SVALID | MD_PS512K | MD_GUARDED) 581 mtspr SPRN_MD_TWC, r0 582 mfspr r0, SPRN_IMMR 583 rlwinm r0, r0, 0, 0xfff80000 584 ori r0, r0, 0xf0 | _PAGE_DIRTY | _PAGE_SPS | _PAGE_SH | \ 585 _PAGE_NO_CACHE | _PAGE_PRESENT 586 mtspr SPRN_MD_RPN, r0 587 lis r0, (MD_TWAM | MD_RSV4I)@h 588 mtspr SPRN_MD_CTR, r0 589#endif 590#ifndef CONFIG_PIN_TLB_TEXT 591 li r0, 0 592 mtspr SPRN_MI_CTR, r0 593#endif 594#if !defined(CONFIG_PIN_TLB_DATA) && !defined(CONFIG_PIN_TLB_IMMR) 595 lis r0, MD_TWAM@h 596 mtspr SPRN_MD_CTR, r0 597#endif 598 tlbia /* Clear all TLB entries */ 599 sync /* wait for tlbia/tlbie to finish */ 600 601 /* set up the PTE pointers for the Abatron bdiGDB. 602 */ 603 lis r5, abatron_pteptrs@h 604 ori r5, r5, abatron_pteptrs@l 605 stw r5, 0xf0(0) /* Must match your Abatron config file */ 606 tophys(r5,r5) 607 lis r6, swapper_pg_dir@h 608 ori r6, r6, swapper_pg_dir@l 609 stw r6, 0(r5) 610 611/* Now turn on the MMU for real! */ 612 li r4,MSR_KERNEL 613 lis r3,start_kernel@h 614 ori r3,r3,start_kernel@l 615 mtspr SPRN_SRR0,r3 616 mtspr SPRN_SRR1,r4 617 rfi /* enable MMU and jump to start_kernel */ 618 619/* Set up the initial MMU state so we can do the first level of 620 * kernel initialization. This maps the first 8 MBytes of memory 1:1 621 * virtual to physical. Also, set the cache mode since that is defined 622 * by TLB entries and perform any additional mapping (like of the IMMR). 623 * If configured to pin some TLBs, we pin the first 8 Mbytes of kernel, 624 * 24 Mbytes of data, and the 512k IMMR space. Anything not covered by 625 * these mappings is mapped by page tables. 626 */ 627SYM_FUNC_START_LOCAL(initial_mmu) 628 li r8, 0 629 mtspr SPRN_MI_CTR, r8 /* remove PINNED ITLB entries */ 630 lis r10, MD_TWAM@h 631 mtspr SPRN_MD_CTR, r10 /* remove PINNED DTLB entries */ 632 633 tlbia /* Invalidate all TLB entries */ 634 635 lis r8, MI_APG_INIT@h /* Set protection modes */ 636 ori r8, r8, MI_APG_INIT@l 637 mtspr SPRN_MI_AP, r8 638 lis r8, MD_APG_INIT@h 639 ori r8, r8, MD_APG_INIT@l 640 mtspr SPRN_MD_AP, r8 641 642 /* Map the lower RAM (up to 32 Mbytes) into the ITLB and DTLB */ 643 lis r8, MI_RSV4I@h 644 ori r8, r8, 0x1c00 645 oris r12, r10, MD_RSV4I@h 646 ori r12, r12, 0x1c00 647 li r9, 4 /* up to 4 pages of 8M */ 648 mtctr r9 649 lis r9, KERNELBASE@h /* Create vaddr for TLB */ 650 li r10, MI_PS8MEG | _PMD_ACCESSED | MI_SVALID 651 li r11, MI_BOOTINIT /* Create RPN for address 0 */ 6521: 653 mtspr SPRN_MI_CTR, r8 /* Set instruction MMU control */ 654 addi r8, r8, 0x100 655 ori r0, r9, MI_EVALID /* Mark it valid */ 656 mtspr SPRN_MI_EPN, r0 657 mtspr SPRN_MI_TWC, r10 658 mtspr SPRN_MI_RPN, r11 /* Store TLB entry */ 659 mtspr SPRN_MD_CTR, r12 660 addi r12, r12, 0x100 661 mtspr SPRN_MD_EPN, r0 662 mtspr SPRN_MD_TWC, r10 663 mtspr SPRN_MD_RPN, r11 664 addis r9, r9, 0x80 665 addis r11, r11, 0x80 666 667 bdnz 1b 668 669 /* Since the cache is enabled according to the information we 670 * just loaded into the TLB, invalidate and enable the caches here. 671 * We should probably check/set other modes....later. 672 */ 673 lis r8, IDC_INVALL@h 674 mtspr SPRN_IC_CST, r8 675 mtspr SPRN_DC_CST, r8 676 lis r8, IDC_ENABLE@h 677 mtspr SPRN_IC_CST, r8 678 mtspr SPRN_DC_CST, r8 679 /* Disable debug mode entry on breakpoints */ 680 mfspr r8, SPRN_DER 681#ifdef CONFIG_PERF_EVENTS 682 rlwinm r8, r8, 0, ~0xc 683#else 684 rlwinm r8, r8, 0, ~0x8 685#endif 686 mtspr SPRN_DER, r8 687 blr 688SYM_FUNC_END(initial_mmu) 689 690#ifdef CONFIG_PIN_TLB 691_GLOBAL(mmu_pin_tlb) 692 lis r9, (1f - PAGE_OFFSET)@h 693 ori r9, r9, (1f - PAGE_OFFSET)@l 694 mfmsr r10 695 mflr r11 696 li r12, MSR_KERNEL & ~(MSR_IR | MSR_DR | MSR_RI) 697 rlwinm r0, r10, 0, ~MSR_RI 698 rlwinm r0, r0, 0, ~MSR_EE 699 mtmsr r0 700 isync 701 .align 4 702 mtspr SPRN_SRR0, r9 703 mtspr SPRN_SRR1, r12 704 rfi 7051: 706 li r5, 0 707 lis r6, MD_TWAM@h 708 mtspr SPRN_MI_CTR, r5 709 mtspr SPRN_MD_CTR, r6 710 tlbia 711 712#ifdef CONFIG_PIN_TLB_TEXT 713 LOAD_REG_IMMEDIATE(r5, 28 << 8) 714 LOAD_REG_IMMEDIATE(r6, PAGE_OFFSET) 715 LOAD_REG_IMMEDIATE(r7, MI_SVALID | MI_PS8MEG | _PMD_ACCESSED) 716 LOAD_REG_IMMEDIATE(r8, 0xf0 | _PAGE_RO | _PAGE_SPS | _PAGE_SH | _PAGE_PRESENT) 717 LOAD_REG_ADDR(r9, _sinittext) 718 li r0, 4 719 mtctr r0 720 7212: ori r0, r6, MI_EVALID 722 mtspr SPRN_MI_CTR, r5 723 mtspr SPRN_MI_EPN, r0 724 mtspr SPRN_MI_TWC, r7 725 mtspr SPRN_MI_RPN, r8 726 addi r5, r5, 0x100 727 addis r6, r6, SZ_8M@h 728 addis r8, r8, SZ_8M@h 729 cmplw r6, r9 730 bdnzt lt, 2b 731 lis r0, MI_RSV4I@h 732 mtspr SPRN_MI_CTR, r0 733#endif 734 735 LOAD_REG_IMMEDIATE(r5, 28 << 8 | MD_TWAM) 736#ifdef CONFIG_PIN_TLB_DATA 737 LOAD_REG_IMMEDIATE(r6, PAGE_OFFSET) 738 LOAD_REG_IMMEDIATE(r7, MI_SVALID | MI_PS8MEG | _PMD_ACCESSED) 739 li r8, 0 740#ifdef CONFIG_PIN_TLB_IMMR 741 li r0, 3 742#else 743 li r0, 4 744#endif 745 mtctr r0 746 cmpwi r4, 0 747 beq 4f 748 LOAD_REG_ADDR(r9, _sinittext) 749 7502: ori r0, r6, MD_EVALID 751 ori r12, r8, 0xf0 | _PAGE_RO | _PAGE_SPS | _PAGE_SH | _PAGE_PRESENT 752 mtspr SPRN_MD_CTR, r5 753 mtspr SPRN_MD_EPN, r0 754 mtspr SPRN_MD_TWC, r7 755 mtspr SPRN_MD_RPN, r12 756 addi r5, r5, 0x100 757 addis r6, r6, SZ_8M@h 758 addis r8, r8, SZ_8M@h 759 cmplw r6, r9 760 bdnzt lt, 2b 7614: 7622: ori r0, r6, MD_EVALID 763 ori r12, r8, 0xf0 | _PAGE_DIRTY | _PAGE_SPS | _PAGE_SH | _PAGE_PRESENT 764 mtspr SPRN_MD_CTR, r5 765 mtspr SPRN_MD_EPN, r0 766 mtspr SPRN_MD_TWC, r7 767 mtspr SPRN_MD_RPN, r12 768 addi r5, r5, 0x100 769 addis r6, r6, SZ_8M@h 770 addis r8, r8, SZ_8M@h 771 cmplw r6, r3 772 bdnzt lt, 2b 773#endif 774#ifdef CONFIG_PIN_TLB_IMMR 775 LOAD_REG_IMMEDIATE(r0, VIRT_IMMR_BASE | MD_EVALID) 776 LOAD_REG_IMMEDIATE(r7, MD_SVALID | MD_PS512K | MD_GUARDED | _PMD_ACCESSED) 777 mfspr r8, SPRN_IMMR 778 rlwinm r8, r8, 0, 0xfff80000 779 ori r8, r8, 0xf0 | _PAGE_DIRTY | _PAGE_SPS | _PAGE_SH | \ 780 _PAGE_NO_CACHE | _PAGE_PRESENT 781 mtspr SPRN_MD_CTR, r5 782 mtspr SPRN_MD_EPN, r0 783 mtspr SPRN_MD_TWC, r7 784 mtspr SPRN_MD_RPN, r8 785#endif 786#if defined(CONFIG_PIN_TLB_IMMR) || defined(CONFIG_PIN_TLB_DATA) 787 lis r0, (MD_RSV4I | MD_TWAM)@h 788 mtspr SPRN_MD_CTR, r0 789#endif 790 mtspr SPRN_SRR1, r10 791 mtspr SPRN_SRR0, r11 792 rfi 793#endif 794