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 <asm/processor.h> 22#include <asm/page.h> 23#include <asm/mmu.h> 24#include <asm/cache.h> 25#include <asm/cputable.h> 26#include <asm/thread_info.h> 27#include <asm/ppc_asm.h> 28#include <asm/asm-offsets.h> 29#include <asm/ptrace.h> 30#include <asm/export.h> 31#include <asm/code-patching-asm.h> 32#include <asm/interrupt.h> 33 34/* 35 * Value for the bits that have fixed value in RPN entries. 36 * Also used for tagging DAR for DTLBerror. 37 */ 38#define RPN_PATTERN 0x00f0 39 40#include "head_32.h" 41 42.macro compare_to_kernel_boundary scratch, addr 43#if CONFIG_TASK_SIZE <= 0x80000000 && CONFIG_PAGE_OFFSET >= 0x80000000 44/* By simply checking Address >= 0x80000000, we know if its a kernel address */ 45 not. \scratch, \addr 46#else 47 rlwinm \scratch, \addr, 16, 0xfff8 48 cmpli cr0, \scratch, PAGE_OFFSET@h 49#endif 50.endm 51 52#define PAGE_SHIFT_512K 19 53#define PAGE_SHIFT_8M 23 54 55 __HEAD 56_GLOBAL(_stext); 57_GLOBAL(_start); 58 59/* MPC8xx 60 * This port was done on an MBX board with an 860. Right now I only 61 * support an ELF compressed (zImage) boot from EPPC-Bug because the 62 * code there loads up some registers before calling us: 63 * r3: ptr to board info data 64 * r4: initrd_start or if no initrd then 0 65 * r5: initrd_end - unused if r4 is 0 66 * r6: Start of command line string 67 * r7: End of command line string 68 * 69 * I decided to use conditional compilation instead of checking PVR and 70 * adding more processor specific branches around code I don't need. 71 * Since this is an embedded processor, I also appreciate any memory 72 * savings I can get. 73 * 74 * The MPC8xx does not have any BATs, but it supports large page sizes. 75 * We first initialize the MMU to support 8M byte pages, then load one 76 * entry into each of the instruction and data TLBs to map the first 77 * 8M 1:1. I also mapped an additional I/O space 1:1 so we can get to 78 * the "internal" processor registers before MMU_init is called. 79 * 80 * -- Dan 81 */ 82 .globl __start 83__start: 84 mr r31,r3 /* save device tree ptr */ 85 86 /* We have to turn on the MMU right away so we get cache modes 87 * set correctly. 88 */ 89 bl initial_mmu 90 91/* We now have the lower 8 Meg mapped into TLB entries, and the caches 92 * ready to work. 93 */ 94 95turn_on_mmu: 96 mfmsr r0 97 ori r0,r0,MSR_DR|MSR_IR 98 mtspr SPRN_SRR1,r0 99 lis r0,start_here@h 100 ori r0,r0,start_here@l 101 mtspr SPRN_SRR0,r0 102 rfi /* enables MMU */ 103 104 105#ifdef CONFIG_PERF_EVENTS 106 .align 4 107 108 .globl itlb_miss_counter 109itlb_miss_counter: 110 .space 4 111 112 .globl dtlb_miss_counter 113dtlb_miss_counter: 114 .space 4 115 116 .globl instruction_counter 117instruction_counter: 118 .space 4 119#endif 120 121/* System reset */ 122 EXCEPTION(INTERRUPT_SYSTEM_RESET, Reset, system_reset_exception) 123 124/* Machine check */ 125 START_EXCEPTION(INTERRUPT_MACHINE_CHECK, MachineCheck) 126 EXCEPTION_PROLOG INTERRUPT_MACHINE_CHECK MachineCheck handle_dar_dsisr=1 127 prepare_transfer_to_handler 128 bl machine_check_exception 129 b interrupt_return 130 131/* External interrupt */ 132 EXCEPTION(INTERRUPT_EXTERNAL, HardwareInterrupt, do_IRQ) 133 134/* Alignment exception */ 135 START_EXCEPTION(INTERRUPT_ALIGNMENT, Alignment) 136 EXCEPTION_PROLOG INTERRUPT_ALIGNMENT Alignment handle_dar_dsisr=1 137 prepare_transfer_to_handler 138 bl alignment_exception 139 REST_NVGPRS(r1) 140 b interrupt_return 141 142/* Program check exception */ 143 START_EXCEPTION(INTERRUPT_PROGRAM, ProgramCheck) 144 EXCEPTION_PROLOG INTERRUPT_PROGRAM ProgramCheck 145 prepare_transfer_to_handler 146 bl program_check_exception 147 REST_NVGPRS(r1) 148 b interrupt_return 149 150/* Decrementer */ 151 EXCEPTION(INTERRUPT_DECREMENTER, Decrementer, timer_interrupt) 152 153/* System call */ 154 START_EXCEPTION(INTERRUPT_SYSCALL, SystemCall) 155 SYSCALL_ENTRY INTERRUPT_SYSCALL 156 157/* Single step - not used on 601 */ 158 EXCEPTION(INTERRUPT_TRACE, SingleStep, single_step_exception) 159 160/* On the MPC8xx, this is a software emulation interrupt. It occurs 161 * for all unimplemented and illegal instructions. 162 */ 163 START_EXCEPTION(INTERRUPT_SOFT_EMU_8xx, SoftEmu) 164 EXCEPTION_PROLOG INTERRUPT_SOFT_EMU_8xx SoftEmu 165 prepare_transfer_to_handler 166 bl emulation_assist_interrupt 167 REST_NVGPRS(r1) 168 b interrupt_return 169 170/* 171 * For the MPC8xx, this is a software tablewalk to load the instruction 172 * TLB. The task switch loads the M_TWB register with the pointer to the first 173 * level table. 174 * If we discover there is no second level table (value is zero) or if there 175 * is an invalid pte, we load that into the TLB, which causes another fault 176 * into the TLB Error interrupt where we can handle such problems. 177 * We have to use the MD_xxx registers for the tablewalk because the 178 * equivalent MI_xxx registers only perform the attribute functions. 179 */ 180 181#ifdef CONFIG_8xx_CPU15 182#define INVALIDATE_ADJACENT_PAGES_CPU15(addr, tmp) \ 183 addi tmp, addr, PAGE_SIZE; \ 184 tlbie tmp; \ 185 addi tmp, addr, -PAGE_SIZE; \ 186 tlbie tmp 187#else 188#define INVALIDATE_ADJACENT_PAGES_CPU15(addr, tmp) 189#endif 190 191 START_EXCEPTION(INTERRUPT_INST_TLB_MISS_8xx, InstructionTLBMiss) 192 mtspr SPRN_SPRG_SCRATCH2, r10 193 mtspr SPRN_M_TW, r11 194 195 /* If we are faulting a kernel address, we have to use the 196 * kernel page tables. 197 */ 198 mfspr r10, SPRN_SRR0 /* Get effective address of fault */ 199 INVALIDATE_ADJACENT_PAGES_CPU15(r10, r11) 200 mtspr SPRN_MD_EPN, r10 201#ifdef CONFIG_MODULES 202 mfcr r11 203 compare_to_kernel_boundary r10, r10 204#endif 205 mfspr r10, SPRN_M_TWB /* Get level 1 table */ 206#ifdef CONFIG_MODULES 207 blt+ 3f 208 rlwinm r10, r10, 0, 20, 31 209 oris r10, r10, (swapper_pg_dir - PAGE_OFFSET)@ha 2103: 211 mtcr r11 212#endif 213 lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r10) /* Get level 1 entry */ 214 mtspr SPRN_MD_TWC, r11 215 mfspr r10, SPRN_MD_TWC 216 lwz r10, 0(r10) /* Get the pte */ 217 rlwimi r11, r10, 0, _PAGE_GUARDED | _PAGE_ACCESSED 218 rlwimi r11, r10, 32 - 9, _PMD_PAGE_512K 219 mtspr SPRN_MI_TWC, r11 220 /* The Linux PTE won't go exactly into the MMU TLB. 221 * Software indicator bits 20 and 23 must be clear. 222 * Software indicator bits 22, 24, 25, 26, and 27 must be 223 * set. All other Linux PTE bits control the behavior 224 * of the MMU. 225 */ 226 rlwinm r10, r10, 0, ~0x0f00 /* Clear bits 20-23 */ 227 rlwimi r10, r10, 4, 0x0400 /* Copy _PAGE_EXEC into bit 21 */ 228 ori r10, r10, RPN_PATTERN | 0x200 /* Set 22 and 24-27 */ 229 mtspr SPRN_MI_RPN, r10 /* Update TLB entry */ 230 231 /* Restore registers */ 2320: mfspr r10, SPRN_SPRG_SCRATCH2 233 mfspr r11, SPRN_M_TW 234 rfi 235 patch_site 0b, patch__itlbmiss_exit_1 236 237#ifdef CONFIG_PERF_EVENTS 238 patch_site 0f, patch__itlbmiss_perf 2390: lwz r10, (itlb_miss_counter - PAGE_OFFSET)@l(0) 240 addi r10, r10, 1 241 stw r10, (itlb_miss_counter - PAGE_OFFSET)@l(0) 242 mfspr r10, SPRN_SPRG_SCRATCH2 243 mfspr r11, SPRN_M_TW 244 rfi 245#endif 246 247 START_EXCEPTION(INTERRUPT_DATA_TLB_MISS_8xx, DataStoreTLBMiss) 248 mtspr SPRN_SPRG_SCRATCH2, r10 249 mtspr SPRN_M_TW, r11 250 mfcr r11 251 252 /* If we are faulting a kernel address, we have to use the 253 * kernel page tables. 254 */ 255 mfspr r10, SPRN_MD_EPN 256 compare_to_kernel_boundary r10, r10 257 mfspr r10, SPRN_M_TWB /* Get level 1 table */ 258 blt+ 3f 259 rlwinm r10, r10, 0, 20, 31 260 oris r10, r10, (swapper_pg_dir - PAGE_OFFSET)@ha 2613: 262 mtcr r11 263 lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r10) /* Get level 1 entry */ 264 265 mtspr SPRN_MD_TWC, r11 266 mfspr r10, SPRN_MD_TWC 267 lwz r10, 0(r10) /* Get the pte */ 268 269 /* Insert Guarded and Accessed flags into the TWC from the Linux PTE. 270 * It is bit 27 of both the Linux PTE and the TWC (at least 271 * I got that right :-). It will be better when we can put 272 * this into the Linux pgd/pmd and load it in the operation 273 * above. 274 */ 275 rlwimi r11, r10, 0, _PAGE_GUARDED | _PAGE_ACCESSED 276 rlwimi r11, r10, 32 - 9, _PMD_PAGE_512K 277 mtspr SPRN_MD_TWC, r11 278 279 /* The Linux PTE won't go exactly into the MMU TLB. 280 * Software indicator bits 24, 25, 26, and 27 must be 281 * set. All other Linux PTE bits control the behavior 282 * of the MMU. 283 */ 284 li r11, RPN_PATTERN 285 rlwimi r10, r11, 0, 24, 27 /* Set 24-27 */ 286 mtspr SPRN_MD_RPN, r10 /* Update TLB entry */ 287 mtspr SPRN_DAR, r11 /* Tag DAR */ 288 289 /* Restore registers */ 290 2910: mfspr r10, SPRN_SPRG_SCRATCH2 292 mfspr r11, SPRN_M_TW 293 rfi 294 patch_site 0b, patch__dtlbmiss_exit_1 295 296#ifdef CONFIG_PERF_EVENTS 297 patch_site 0f, patch__dtlbmiss_perf 2980: lwz r10, (dtlb_miss_counter - PAGE_OFFSET)@l(0) 299 addi r10, r10, 1 300 stw r10, (dtlb_miss_counter - PAGE_OFFSET)@l(0) 301 mfspr r10, SPRN_SPRG_SCRATCH2 302 mfspr r11, SPRN_M_TW 303 rfi 304#endif 305 306/* This is an instruction TLB error on the MPC8xx. This could be due 307 * to many reasons, such as executing guarded memory or illegal instruction 308 * addresses. There is nothing to do but handle a big time error fault. 309 */ 310 START_EXCEPTION(INTERRUPT_INST_TLB_ERROR_8xx, InstructionTLBError) 311 /* 0x400 is InstructionAccess exception, needed by bad_page_fault() */ 312 EXCEPTION_PROLOG INTERRUPT_INST_STORAGE InstructionTLBError 313 andis. r5,r9,DSISR_SRR1_MATCH_32S@h /* Filter relevant SRR1 bits */ 314 andis. r10,r9,SRR1_ISI_NOPT@h 315 beq+ .Litlbie 316 tlbie r12 317.Litlbie: 318 stw r12, _DAR(r11) 319 stw r5, _DSISR(r11) 320 prepare_transfer_to_handler 321 bl do_page_fault 322 b interrupt_return 323 324/* This is the data TLB error on the MPC8xx. This could be due to 325 * many reasons, including a dirty update to a pte. We bail out to 326 * a higher level function that can handle it. 327 */ 328 START_EXCEPTION(INTERRUPT_DATA_TLB_ERROR_8xx, DataTLBError) 329 EXCEPTION_PROLOG_0 handle_dar_dsisr=1 330 mfspr r11, SPRN_DAR 331 cmpwi cr1, r11, RPN_PATTERN 332 beq- cr1, FixupDAR /* must be a buggy dcbX, icbi insn. */ 333DARFixed:/* Return from dcbx instruction bug workaround */ 334 EXCEPTION_PROLOG_1 335 /* 0x300 is DataAccess exception, needed by bad_page_fault() */ 336 EXCEPTION_PROLOG_2 INTERRUPT_DATA_STORAGE DataTLBError handle_dar_dsisr=1 337 lwz r4, _DAR(r11) 338 lwz r5, _DSISR(r11) 339 andis. r10,r5,DSISR_NOHPTE@h 340 beq+ .Ldtlbie 341 tlbie r4 342.Ldtlbie: 343 prepare_transfer_to_handler 344 bl do_page_fault 345 b interrupt_return 346 347#ifdef CONFIG_VMAP_STACK 348 vmap_stack_overflow_exception 349#endif 350 351/* On the MPC8xx, these next four traps are used for development 352 * support of breakpoints and such. Someday I will get around to 353 * using them. 354 */ 355 START_EXCEPTION(INTERRUPT_DATA_BREAKPOINT_8xx, DataBreakpoint) 356 EXCEPTION_PROLOG_0 handle_dar_dsisr=1 357 mfspr r11, SPRN_SRR0 358 cmplwi cr1, r11, (.Ldtlbie - PAGE_OFFSET)@l 359 cmplwi cr7, r11, (.Litlbie - PAGE_OFFSET)@l 360 cror 4*cr1+eq, 4*cr1+eq, 4*cr7+eq 361 bne cr1, 1f 362 mtcr r10 363 mfspr r10, SPRN_SPRG_SCRATCH0 364 mfspr r11, SPRN_SPRG_SCRATCH1 365 rfi 366 3671: EXCEPTION_PROLOG_1 368 EXCEPTION_PROLOG_2 INTERRUPT_DATA_BREAKPOINT_8xx DataBreakpoint handle_dar_dsisr=1 369 mfspr r4,SPRN_BAR 370 stw r4,_DAR(r11) 371 prepare_transfer_to_handler 372 bl do_break 373 REST_NVGPRS(r1) 374 b interrupt_return 375 376#ifdef CONFIG_PERF_EVENTS 377 START_EXCEPTION(INTERRUPT_INST_BREAKPOINT_8xx, InstructionBreakpoint) 378 mtspr SPRN_SPRG_SCRATCH0, r10 379 lwz r10, (instruction_counter - PAGE_OFFSET)@l(0) 380 addi r10, r10, -1 381 stw r10, (instruction_counter - PAGE_OFFSET)@l(0) 382 lis r10, 0xffff 383 ori r10, r10, 0x01 384 mtspr SPRN_COUNTA, r10 385 mfspr r10, SPRN_SPRG_SCRATCH0 386 rfi 387#else 388 EXCEPTION(INTERRUPT_INST_BREAKPOINT_8xx, Trap_1d, unknown_exception) 389#endif 390 EXCEPTION(0x1e00, Trap_1e, unknown_exception) 391 EXCEPTION(0x1f00, Trap_1f, unknown_exception) 392 393 __HEAD 394 . = 0x2000 395 396/* This is the procedure to calculate the data EA for buggy dcbx,dcbi instructions 397 * by decoding the registers used by the dcbx instruction and adding them. 398 * DAR is set to the calculated address. 399 */ 400FixupDAR:/* Entry point for dcbx workaround. */ 401 mtspr SPRN_M_TW, r10 402 /* fetch instruction from memory. */ 403 mfspr r10, SPRN_SRR0 404 mtspr SPRN_MD_EPN, r10 405 rlwinm r11, r10, 16, 0xfff8 406 cmpli cr1, r11, PAGE_OFFSET@h 407 mfspr r11, SPRN_M_TWB /* Get level 1 table */ 408 blt+ cr1, 3f 409 410 /* create physical page address from effective address */ 411 tophys(r11, r10) 412 mfspr r11, SPRN_M_TWB /* Get level 1 table */ 413 rlwinm r11, r11, 0, 20, 31 414 oris r11, r11, (swapper_pg_dir - PAGE_OFFSET)@ha 4153: 416 lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r11) /* Get the level 1 entry */ 417 mtspr SPRN_MD_TWC, r11 418 mtcrf 0x01, r11 419 mfspr r11, SPRN_MD_TWC 420 lwz r11, 0(r11) /* Get the pte */ 421 bt 28,200f /* bit 28 = Large page (8M) */ 422 /* concat physical page address(r11) and page offset(r10) */ 423 rlwimi r11, r10, 0, 32 - PAGE_SHIFT, 31 424201: 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 443200: 444 /* concat physical page address(r11) and page offset(r10) */ 445 rlwimi r11, r10, 0, 32 - PAGE_SHIFT_8M, 31 446 b 201b 447 448144: mfspr r10, SPRN_DSISR 449 rlwinm r10, r10,0,7,5 /* Clear store bit for buggy dcbst insn */ 450 mtspr SPRN_DSISR, r10 451142: /* continue, it was a dcbx, dcbi instruction. */ 452 mfctr r10 453 mtdar r10 /* save ctr reg in DAR */ 454 rlwinm r10, r11, 24, 24, 28 /* offset into jump table for reg RB */ 455 addi r10, r10, 150f@l /* add start of table */ 456 mtctr r10 /* load ctr with jump address */ 457 xor r10, r10, r10 /* sum starts at zero */ 458 bctr /* jump into table */ 459150: 460 add r10, r10, r0 ;b 151f 461 add r10, r10, r1 ;b 151f 462 add r10, r10, r2 ;b 151f 463 add r10, r10, r3 ;b 151f 464 add r10, r10, r4 ;b 151f 465 add r10, r10, r5 ;b 151f 466 add r10, r10, r6 ;b 151f 467 add r10, r10, r7 ;b 151f 468 add r10, r10, r8 ;b 151f 469 add r10, r10, r9 ;b 151f 470 mtctr r11 ;b 154f /* r10 needs special handling */ 471 mtctr r11 ;b 153f /* r11 needs special handling */ 472 add r10, r10, r12 ;b 151f 473 add r10, r10, r13 ;b 151f 474 add r10, r10, r14 ;b 151f 475 add r10, r10, r15 ;b 151f 476 add r10, r10, r16 ;b 151f 477 add r10, r10, r17 ;b 151f 478 add r10, r10, r18 ;b 151f 479 add r10, r10, r19 ;b 151f 480 add r10, r10, r20 ;b 151f 481 add r10, r10, r21 ;b 151f 482 add r10, r10, r22 ;b 151f 483 add r10, r10, r23 ;b 151f 484 add r10, r10, r24 ;b 151f 485 add r10, r10, r25 ;b 151f 486 add r10, r10, r26 ;b 151f 487 add r10, r10, r27 ;b 151f 488 add r10, r10, r28 ;b 151f 489 add r10, r10, r29 ;b 151f 490 add r10, r10, r30 ;b 151f 491 add r10, r10, r31 492151: 493 rlwinm r11,r11,19,24,28 /* offset into jump table for reg RA */ 494 cmpwi cr1, r11, 0 495 beq cr1, 152f /* if reg RA is zero, don't add it */ 496 addi r11, r11, 150b@l /* add start of table */ 497 mtctr r11 /* load ctr with jump address */ 498 rlwinm r11,r11,0,16,10 /* make sure we don't execute this more than once */ 499 bctr /* jump into table */ 500152: 501 mfdar r11 502 mtctr r11 /* restore ctr reg from DAR */ 503 mfspr r11, SPRN_SPRG_THREAD 504 stw r10, DAR(r11) 505 mfspr r10, SPRN_DSISR 506 stw r10, DSISR(r11) 507 mfspr r10,SPRN_M_TW 508 b DARFixed /* Go back to normal TLB handling */ 509 510 /* special handling for r10,r11 since these are modified already */ 511153: mfspr r11, SPRN_SPRG_SCRATCH1 /* load r11 from SPRN_SPRG_SCRATCH1 */ 512 add r10, r10, r11 /* add it */ 513 mfctr r11 /* restore r11 */ 514 b 151b 515154: mfspr r11, SPRN_SPRG_SCRATCH0 /* load r10 from SPRN_SPRG_SCRATCH0 */ 516 add r10, r10, r11 /* add it */ 517 mfctr r11 /* restore r11 */ 518 b 151b 519 520/* 521 * This is where the main kernel code starts. 522 */ 523start_here: 524 /* ptr to current */ 525 lis r2,init_task@h 526 ori r2,r2,init_task@l 527 528 /* ptr to phys current thread */ 529 tophys(r4,r2) 530 addi r4,r4,THREAD /* init task's THREAD */ 531 mtspr SPRN_SPRG_THREAD,r4 532 533 /* stack */ 534 lis r1,init_thread_union@ha 535 addi r1,r1,init_thread_union@l 536 lis r0, STACK_END_MAGIC@h 537 ori r0, r0, STACK_END_MAGIC@l 538 stw r0, 0(r1) 539 li r0,0 540 stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1) 541 542 lis r6, swapper_pg_dir@ha 543 tophys(r6,r6) 544 mtspr SPRN_M_TWB, r6 545 546 bl early_init /* We have to do this with MMU on */ 547 548/* 549 * Decide what sort of machine this is and initialize the MMU. 550 */ 551#ifdef CONFIG_KASAN 552 bl kasan_early_init 553#endif 554 li r3,0 555 mr r4,r31 556 bl machine_init 557 bl MMU_init 558 559/* 560 * Go back to running unmapped so we can load up new values 561 * and change to using our exception vectors. 562 * On the 8xx, all we have to do is invalidate the TLB to clear 563 * the old 8M byte TLB mappings and load the page table base register. 564 */ 565 /* The right way to do this would be to track it down through 566 * init's THREAD like the context switch code does, but this is 567 * easier......until someone changes init's static structures. 568 */ 569 lis r4,2f@h 570 ori r4,r4,2f@l 571 tophys(r4,r4) 572 li r3,MSR_KERNEL & ~(MSR_IR|MSR_DR) 573 mtspr SPRN_SRR0,r4 574 mtspr SPRN_SRR1,r3 575 rfi 576/* Load up the kernel context */ 5772: 578#ifdef CONFIG_PIN_TLB_IMMR 579 lis r0, MD_TWAM@h 580 oris r0, r0, 0x1f00 581 mtspr SPRN_MD_CTR, r0 582 LOAD_REG_IMMEDIATE(r0, VIRT_IMMR_BASE | MD_EVALID) 583 tlbie r0 584 mtspr SPRN_MD_EPN, r0 585 LOAD_REG_IMMEDIATE(r0, MD_SVALID | MD_PS512K | MD_GUARDED) 586 mtspr SPRN_MD_TWC, r0 587 mfspr r0, SPRN_IMMR 588 rlwinm r0, r0, 0, 0xfff80000 589 ori r0, r0, 0xf0 | _PAGE_DIRTY | _PAGE_SPS | _PAGE_SH | \ 590 _PAGE_NO_CACHE | _PAGE_PRESENT 591 mtspr SPRN_MD_RPN, r0 592 lis r0, (MD_TWAM | MD_RSV4I)@h 593 mtspr SPRN_MD_CTR, r0 594#endif 595#if !defined(CONFIG_PIN_TLB_DATA) && !defined(CONFIG_PIN_TLB_IMMR) 596 lis r0, MD_TWAM@h 597 mtspr SPRN_MD_CTR, r0 598#endif 599 tlbia /* Clear all TLB entries */ 600 sync /* wait for tlbia/tlbie to finish */ 601 602 /* set up the PTE pointers for the Abatron bdiGDB. 603 */ 604 lis r5, abatron_pteptrs@h 605 ori r5, r5, abatron_pteptrs@l 606 stw r5, 0xf0(0) /* Must match your Abatron config file */ 607 tophys(r5,r5) 608 lis r6, swapper_pg_dir@h 609 ori r6, r6, swapper_pg_dir@l 610 stw r6, 0(r5) 611 612/* Now turn on the MMU for real! */ 613 li r4,MSR_KERNEL 614 lis r3,start_kernel@h 615 ori r3,r3,start_kernel@l 616 mtspr SPRN_SRR0,r3 617 mtspr SPRN_SRR1,r4 618 rfi /* enable MMU and jump to start_kernel */ 619 620/* Set up the initial MMU state so we can do the first level of 621 * kernel initialization. This maps the first 8 MBytes of memory 1:1 622 * virtual to physical. Also, set the cache mode since that is defined 623 * by TLB entries and perform any additional mapping (like of the IMMR). 624 * If configured to pin some TLBs, we pin the first 8 Mbytes of kernel, 625 * 24 Mbytes of data, and the 512k IMMR space. Anything not covered by 626 * these mappings is mapped by page tables. 627 */ 628initial_mmu: 629 li r8, 0 630 mtspr SPRN_MI_CTR, r8 /* remove PINNED ITLB entries */ 631 lis r10, MD_TWAM@h 632 mtspr SPRN_MD_CTR, r10 /* remove PINNED DTLB entries */ 633 634 tlbia /* Invalidate all TLB entries */ 635 636 lis r8, MI_APG_INIT@h /* Set protection modes */ 637 ori r8, r8, MI_APG_INIT@l 638 mtspr SPRN_MI_AP, r8 639 lis r8, MD_APG_INIT@h 640 ori r8, r8, MD_APG_INIT@l 641 mtspr SPRN_MD_AP, r8 642 643 /* Map the lower RAM (up to 32 Mbytes) into the ITLB and DTLB */ 644 lis r8, MI_RSV4I@h 645 ori r8, r8, 0x1c00 646 oris r12, r10, MD_RSV4I@h 647 ori r12, r12, 0x1c00 648 li r9, 4 /* up to 4 pages of 8M */ 649 mtctr r9 650 lis r9, KERNELBASE@h /* Create vaddr for TLB */ 651 li r10, MI_PS8MEG | _PMD_ACCESSED | MI_SVALID 652 li r11, MI_BOOTINIT /* Create RPN for address 0 */ 6531: 654 mtspr SPRN_MI_CTR, r8 /* Set instruction MMU control */ 655 addi r8, r8, 0x100 656 ori r0, r9, MI_EVALID /* Mark it valid */ 657 mtspr SPRN_MI_EPN, r0 658 mtspr SPRN_MI_TWC, r10 659 mtspr SPRN_MI_RPN, r11 /* Store TLB entry */ 660 mtspr SPRN_MD_CTR, r12 661 addi r12, r12, 0x100 662 mtspr SPRN_MD_EPN, r0 663 mtspr SPRN_MD_TWC, r10 664 mtspr SPRN_MD_RPN, r11 665 addis r9, r9, 0x80 666 addis r11, r11, 0x80 667 668 bdnz 1b 669 670 /* Since the cache is enabled according to the information we 671 * just loaded into the TLB, invalidate and enable the caches here. 672 * We should probably check/set other modes....later. 673 */ 674 lis r8, IDC_INVALL@h 675 mtspr SPRN_IC_CST, r8 676 mtspr SPRN_DC_CST, r8 677 lis r8, IDC_ENABLE@h 678 mtspr SPRN_IC_CST, r8 679 mtspr SPRN_DC_CST, r8 680 /* Disable debug mode entry on breakpoints */ 681 mfspr r8, SPRN_DER 682#ifdef CONFIG_PERF_EVENTS 683 rlwinm r8, r8, 0, ~0xc 684#else 685 rlwinm r8, r8, 0, ~0x8 686#endif 687 mtspr SPRN_DER, r8 688 blr 689 690_GLOBAL(mmu_pin_tlb) 691 lis r9, (1f - PAGE_OFFSET)@h 692 ori r9, r9, (1f - PAGE_OFFSET)@l 693 mfmsr r10 694 mflr r11 695 li r12, MSR_KERNEL & ~(MSR_IR | MSR_DR | MSR_RI) 696 rlwinm r0, r10, 0, ~MSR_RI 697 rlwinm r0, r0, 0, ~MSR_EE 698 mtmsr r0 699 isync 700 .align 4 701 mtspr SPRN_SRR0, r9 702 mtspr SPRN_SRR1, r12 703 rfi 7041: 705 li r5, 0 706 lis r6, MD_TWAM@h 707 mtspr SPRN_MI_CTR, r5 708 mtspr SPRN_MD_CTR, r6 709 tlbia 710 711 LOAD_REG_IMMEDIATE(r5, 28 << 8) 712 LOAD_REG_IMMEDIATE(r6, PAGE_OFFSET) 713 LOAD_REG_IMMEDIATE(r7, MI_SVALID | MI_PS8MEG | _PMD_ACCESSED) 714 LOAD_REG_IMMEDIATE(r8, 0xf0 | _PAGE_RO | _PAGE_SPS | _PAGE_SH | _PAGE_PRESENT) 715 LOAD_REG_ADDR(r9, _sinittext) 716 li r0, 4 717 mtctr r0 718 7192: ori r0, r6, MI_EVALID 720 mtspr SPRN_MI_CTR, r5 721 mtspr SPRN_MI_EPN, r0 722 mtspr SPRN_MI_TWC, r7 723 mtspr SPRN_MI_RPN, r8 724 addi r5, r5, 0x100 725 addis r6, r6, SZ_8M@h 726 addis r8, r8, SZ_8M@h 727 cmplw r6, r9 728 bdnzt lt, 2b 729 lis r0, MI_RSV4I@h 730 mtspr SPRN_MI_CTR, r0 731 732 LOAD_REG_IMMEDIATE(r5, 28 << 8 | MD_TWAM) 733#ifdef CONFIG_PIN_TLB_DATA 734 LOAD_REG_IMMEDIATE(r6, PAGE_OFFSET) 735 LOAD_REG_IMMEDIATE(r7, MI_SVALID | MI_PS8MEG | _PMD_ACCESSED) 736 li r8, 0 737#ifdef CONFIG_PIN_TLB_IMMR 738 li r0, 3 739#else 740 li r0, 4 741#endif 742 mtctr r0 743 cmpwi r4, 0 744 beq 4f 745 LOAD_REG_ADDR(r9, _sinittext) 746 7472: ori r0, r6, MD_EVALID 748 ori r12, r8, 0xf0 | _PAGE_RO | _PAGE_SPS | _PAGE_SH | _PAGE_PRESENT 749 mtspr SPRN_MD_CTR, r5 750 mtspr SPRN_MD_EPN, r0 751 mtspr SPRN_MD_TWC, r7 752 mtspr SPRN_MD_RPN, r12 753 addi r5, r5, 0x100 754 addis r6, r6, SZ_8M@h 755 addis r8, r8, SZ_8M@h 756 cmplw r6, r9 757 bdnzt lt, 2b 7584: 7592: ori r0, r6, MD_EVALID 760 ori r12, r8, 0xf0 | _PAGE_DIRTY | _PAGE_SPS | _PAGE_SH | _PAGE_PRESENT 761 mtspr SPRN_MD_CTR, r5 762 mtspr SPRN_MD_EPN, r0 763 mtspr SPRN_MD_TWC, r7 764 mtspr SPRN_MD_RPN, r12 765 addi r5, r5, 0x100 766 addis r6, r6, SZ_8M@h 767 addis r8, r8, SZ_8M@h 768 cmplw r6, r3 769 bdnzt lt, 2b 770#endif 771#ifdef CONFIG_PIN_TLB_IMMR 772 LOAD_REG_IMMEDIATE(r0, VIRT_IMMR_BASE | MD_EVALID) 773 LOAD_REG_IMMEDIATE(r7, MD_SVALID | MD_PS512K | MD_GUARDED | _PMD_ACCESSED) 774 mfspr r8, SPRN_IMMR 775 rlwinm r8, r8, 0, 0xfff80000 776 ori r8, r8, 0xf0 | _PAGE_DIRTY | _PAGE_SPS | _PAGE_SH | \ 777 _PAGE_NO_CACHE | _PAGE_PRESENT 778 mtspr SPRN_MD_CTR, r5 779 mtspr SPRN_MD_EPN, r0 780 mtspr SPRN_MD_TWC, r7 781 mtspr SPRN_MD_RPN, r8 782#endif 783#if defined(CONFIG_PIN_TLB_IMMR) || defined(CONFIG_PIN_TLB_DATA) 784 lis r0, (MD_RSV4I | MD_TWAM)@h 785 mtspr SPRN_MD_CTR, r0 786#endif 787 mtspr SPRN_SRR1, r10 788 mtspr SPRN_SRR0, r11 789 rfi 790