1/* 2 * PowerPC version 3 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org) 4 * 5 * Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP 6 * Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu> 7 * Adapted for Power Macintosh by Paul Mackerras. 8 * Low-level exception handlers and MMU support 9 * rewritten by Paul Mackerras. 10 * Copyright (C) 1996 Paul Mackerras. 11 * 12 * Adapted for 64bit PowerPC by Dave Engebretsen, Peter Bergner, and 13 * Mike Corrigan {engebret|bergner|mikejc}@us.ibm.com 14 * 15 * This file contains the entry point for the 64-bit kernel along 16 * with some early initialization code common to all 64-bit powerpc 17 * variants. 18 * 19 * This program is free software; you can redistribute it and/or 20 * modify it under the terms of the GNU General Public License 21 * as published by the Free Software Foundation; either version 22 * 2 of the License, or (at your option) any later version. 23 */ 24 25#include <linux/threads.h> 26#include <asm/reg.h> 27#include <asm/page.h> 28#include <asm/mmu.h> 29#include <asm/ppc_asm.h> 30#include <asm/asm-offsets.h> 31#include <asm/bug.h> 32#include <asm/cputable.h> 33#include <asm/setup.h> 34#include <asm/hvcall.h> 35#include <asm/thread_info.h> 36#include <asm/firmware.h> 37#include <asm/page_64.h> 38#include <asm/irqflags.h> 39#include <asm/kvm_book3s_asm.h> 40#include <asm/ptrace.h> 41#include <asm/hw_irq.h> 42 43/* The physical memory is laid out such that the secondary processor 44 * spin code sits at 0x0000...0x00ff. On server, the vectors follow 45 * using the layout described in exceptions-64s.S 46 */ 47 48/* 49 * Entering into this code we make the following assumptions: 50 * 51 * For pSeries or server processors: 52 * 1. The MMU is off & open firmware is running in real mode. 53 * 2. The kernel is entered at __start 54 * -or- For OPAL entry: 55 * 1. The MMU is off, processor in HV mode, primary CPU enters at 0 56 * with device-tree in gpr3. We also get OPAL base in r8 and 57 * entry in r9 for debugging purposes 58 * 2. Secondary processors enter at 0x60 with PIR in gpr3 59 * 60 * For Book3E processors: 61 * 1. The MMU is on running in AS0 in a state defined in ePAPR 62 * 2. The kernel is entered at __start 63 */ 64 65 .text 66 .globl _stext 67_stext: 68_GLOBAL(__start) 69 /* NOP this out unconditionally */ 70BEGIN_FTR_SECTION 71 b .__start_initialization_multiplatform 72END_FTR_SECTION(0, 1) 73 74 /* Catch branch to 0 in real mode */ 75 trap 76 77 /* Secondary processors spin on this value until it becomes nonzero. 78 * When it does it contains the real address of the descriptor 79 * of the function that the cpu should jump to to continue 80 * initialization. 81 */ 82 .globl __secondary_hold_spinloop 83__secondary_hold_spinloop: 84 .llong 0x0 85 86 /* Secondary processors write this value with their cpu # */ 87 /* after they enter the spin loop immediately below. */ 88 .globl __secondary_hold_acknowledge 89__secondary_hold_acknowledge: 90 .llong 0x0 91 92#ifdef CONFIG_RELOCATABLE 93 /* This flag is set to 1 by a loader if the kernel should run 94 * at the loaded address instead of the linked address. This 95 * is used by kexec-tools to keep the the kdump kernel in the 96 * crash_kernel region. The loader is responsible for 97 * observing the alignment requirement. 98 */ 99 /* Do not move this variable as kexec-tools knows about it. */ 100 . = 0x5c 101 .globl __run_at_load 102__run_at_load: 103 .long 0x72756e30 /* "run0" -- relocate to 0 by default */ 104#endif 105 106 . = 0x60 107/* 108 * The following code is used to hold secondary processors 109 * in a spin loop after they have entered the kernel, but 110 * before the bulk of the kernel has been relocated. This code 111 * is relocated to physical address 0x60 before prom_init is run. 112 * All of it must fit below the first exception vector at 0x100. 113 * Use .globl here not _GLOBAL because we want __secondary_hold 114 * to be the actual text address, not a descriptor. 115 */ 116 .globl __secondary_hold 117__secondary_hold: 118#ifndef CONFIG_PPC_BOOK3E 119 mfmsr r24 120 ori r24,r24,MSR_RI 121 mtmsrd r24 /* RI on */ 122#endif 123 /* Grab our physical cpu number */ 124 mr r24,r3 125 /* stash r4 for book3e */ 126 mr r25,r4 127 128 /* Tell the master cpu we're here */ 129 /* Relocation is off & we are located at an address less */ 130 /* than 0x100, so only need to grab low order offset. */ 131 std r24,__secondary_hold_acknowledge-_stext(0) 132 sync 133 134 li r26,0 135#ifdef CONFIG_PPC_BOOK3E 136 tovirt(r26,r26) 137#endif 138 /* All secondary cpus wait here until told to start. */ 139100: ld r4,__secondary_hold_spinloop-_stext(r26) 140 cmpdi 0,r4,0 141 beq 100b 142 143#if defined(CONFIG_SMP) || defined(CONFIG_KEXEC) 144#ifdef CONFIG_PPC_BOOK3E 145 tovirt(r4,r4) 146#endif 147 ld r4,0(r4) /* deref function descriptor */ 148 mtctr r4 149 mr r3,r24 150 /* 151 * it may be the case that other platforms have r4 right to 152 * begin with, this gives us some safety in case it is not 153 */ 154#ifdef CONFIG_PPC_BOOK3E 155 mr r4,r25 156#else 157 li r4,0 158#endif 159 /* Make sure that patched code is visible */ 160 isync 161 bctr 162#else 163 BUG_OPCODE 164#endif 165 166/* This value is used to mark exception frames on the stack. */ 167 .section ".toc","aw" 168exception_marker: 169 .tc ID_72656773_68657265[TC],0x7265677368657265 170 .text 171 172/* 173 * On server, we include the exception vectors code here as it 174 * relies on absolute addressing which is only possible within 175 * this compilation unit 176 */ 177#ifdef CONFIG_PPC_BOOK3S 178#include "exceptions-64s.S" 179#endif 180 181_GLOBAL(generic_secondary_thread_init) 182 mr r24,r3 183 184 /* turn on 64-bit mode */ 185 bl .enable_64b_mode 186 187 /* get a valid TOC pointer, wherever we're mapped at */ 188 bl .relative_toc 189 tovirt(r2,r2) 190 191#ifdef CONFIG_PPC_BOOK3E 192 /* Book3E initialization */ 193 mr r3,r24 194 bl .book3e_secondary_thread_init 195#endif 196 b generic_secondary_common_init 197 198/* 199 * On pSeries and most other platforms, secondary processors spin 200 * in the following code. 201 * At entry, r3 = this processor's number (physical cpu id) 202 * 203 * On Book3E, r4 = 1 to indicate that the initial TLB entry for 204 * this core already exists (setup via some other mechanism such 205 * as SCOM before entry). 206 */ 207_GLOBAL(generic_secondary_smp_init) 208 mr r24,r3 209 mr r25,r4 210 211 /* turn on 64-bit mode */ 212 bl .enable_64b_mode 213 214 /* get a valid TOC pointer, wherever we're mapped at */ 215 bl .relative_toc 216 tovirt(r2,r2) 217 218#ifdef CONFIG_PPC_BOOK3E 219 /* Book3E initialization */ 220 mr r3,r24 221 mr r4,r25 222 bl .book3e_secondary_core_init 223#endif 224 225generic_secondary_common_init: 226 /* Set up a paca value for this processor. Since we have the 227 * physical cpu id in r24, we need to search the pacas to find 228 * which logical id maps to our physical one. 229 */ 230 LOAD_REG_ADDR(r13, paca) /* Load paca pointer */ 231 ld r13,0(r13) /* Get base vaddr of paca array */ 232#ifndef CONFIG_SMP 233 addi r13,r13,PACA_SIZE /* know r13 if used accidentally */ 234 b .kexec_wait /* wait for next kernel if !SMP */ 235#else 236 LOAD_REG_ADDR(r7, nr_cpu_ids) /* Load nr_cpu_ids address */ 237 lwz r7,0(r7) /* also the max paca allocated */ 238 li r5,0 /* logical cpu id */ 2391: lhz r6,PACAHWCPUID(r13) /* Load HW procid from paca */ 240 cmpw r6,r24 /* Compare to our id */ 241 beq 2f 242 addi r13,r13,PACA_SIZE /* Loop to next PACA on miss */ 243 addi r5,r5,1 244 cmpw r5,r7 /* Check if more pacas exist */ 245 blt 1b 246 247 mr r3,r24 /* not found, copy phys to r3 */ 248 b .kexec_wait /* next kernel might do better */ 249 2502: SET_PACA(r13) 251#ifdef CONFIG_PPC_BOOK3E 252 addi r12,r13,PACA_EXTLB /* and TLB exc frame in another */ 253 mtspr SPRN_SPRG_TLB_EXFRAME,r12 254#endif 255 256 /* From now on, r24 is expected to be logical cpuid */ 257 mr r24,r5 258 259 /* See if we need to call a cpu state restore handler */ 260 LOAD_REG_ADDR(r23, cur_cpu_spec) 261 ld r23,0(r23) 262 ld r23,CPU_SPEC_RESTORE(r23) 263 cmpdi 0,r23,0 264 beq 3f 265 ld r23,0(r23) 266 mtctr r23 267 bctrl 268 2693: LOAD_REG_ADDR(r3, spinning_secondaries) /* Decrement spinning_secondaries */ 270 lwarx r4,0,r3 271 subi r4,r4,1 272 stwcx. r4,0,r3 273 bne 3b 274 isync 275 2764: HMT_LOW 277 lbz r23,PACAPROCSTART(r13) /* Test if this processor should */ 278 /* start. */ 279 cmpwi 0,r23,0 280 beq 4b /* Loop until told to go */ 281 282 sync /* order paca.run and cur_cpu_spec */ 283 isync /* In case code patching happened */ 284 285 /* Create a temp kernel stack for use before relocation is on. */ 286 ld r1,PACAEMERGSP(r13) 287 subi r1,r1,STACK_FRAME_OVERHEAD 288 289 b __secondary_start 290#endif /* SMP */ 291 292/* 293 * Turn the MMU off. 294 * Assumes we're mapped EA == RA if the MMU is on. 295 */ 296#ifdef CONFIG_PPC_BOOK3S 297_STATIC(__mmu_off) 298 mfmsr r3 299 andi. r0,r3,MSR_IR|MSR_DR 300 beqlr 301 mflr r4 302 andc r3,r3,r0 303 mtspr SPRN_SRR0,r4 304 mtspr SPRN_SRR1,r3 305 sync 306 rfid 307 b . /* prevent speculative execution */ 308#endif 309 310 311/* 312 * Here is our main kernel entry point. We support currently 2 kind of entries 313 * depending on the value of r5. 314 * 315 * r5 != NULL -> OF entry, we go to prom_init, "legacy" parameter content 316 * in r3...r7 317 * 318 * r5 == NULL -> kexec style entry. r3 is a physical pointer to the 319 * DT block, r4 is a physical pointer to the kernel itself 320 * 321 */ 322_GLOBAL(__start_initialization_multiplatform) 323 /* Make sure we are running in 64 bits mode */ 324 bl .enable_64b_mode 325 326 /* Get TOC pointer (current runtime address) */ 327 bl .relative_toc 328 329 /* find out where we are now */ 330 bcl 20,31,$+4 3310: mflr r26 /* r26 = runtime addr here */ 332 addis r26,r26,(_stext - 0b)@ha 333 addi r26,r26,(_stext - 0b)@l /* current runtime base addr */ 334 335 /* 336 * Are we booted from a PROM Of-type client-interface ? 337 */ 338 cmpldi cr0,r5,0 339 beq 1f 340 b .__boot_from_prom /* yes -> prom */ 3411: 342 /* Save parameters */ 343 mr r31,r3 344 mr r30,r4 345#ifdef CONFIG_PPC_EARLY_DEBUG_OPAL 346 /* Save OPAL entry */ 347 mr r28,r8 348 mr r29,r9 349#endif 350 351#ifdef CONFIG_PPC_BOOK3E 352 bl .start_initialization_book3e 353 b .__after_prom_start 354#else 355 /* Setup some critical 970 SPRs before switching MMU off */ 356 mfspr r0,SPRN_PVR 357 srwi r0,r0,16 358 cmpwi r0,0x39 /* 970 */ 359 beq 1f 360 cmpwi r0,0x3c /* 970FX */ 361 beq 1f 362 cmpwi r0,0x44 /* 970MP */ 363 beq 1f 364 cmpwi r0,0x45 /* 970GX */ 365 bne 2f 3661: bl .__cpu_preinit_ppc970 3672: 368 369 /* Switch off MMU if not already off */ 370 bl .__mmu_off 371 b .__after_prom_start 372#endif /* CONFIG_PPC_BOOK3E */ 373 374_INIT_STATIC(__boot_from_prom) 375#ifdef CONFIG_PPC_OF_BOOT_TRAMPOLINE 376 /* Save parameters */ 377 mr r31,r3 378 mr r30,r4 379 mr r29,r5 380 mr r28,r6 381 mr r27,r7 382 383 /* 384 * Align the stack to 16-byte boundary 385 * Depending on the size and layout of the ELF sections in the initial 386 * boot binary, the stack pointer may be unaligned on PowerMac 387 */ 388 rldicr r1,r1,0,59 389 390#ifdef CONFIG_RELOCATABLE 391 /* Relocate code for where we are now */ 392 mr r3,r26 393 bl .relocate 394#endif 395 396 /* Restore parameters */ 397 mr r3,r31 398 mr r4,r30 399 mr r5,r29 400 mr r6,r28 401 mr r7,r27 402 403 /* Do all of the interaction with OF client interface */ 404 mr r8,r26 405 bl .prom_init 406#endif /* #CONFIG_PPC_OF_BOOT_TRAMPOLINE */ 407 408 /* We never return. We also hit that trap if trying to boot 409 * from OF while CONFIG_PPC_OF_BOOT_TRAMPOLINE isn't selected */ 410 trap 411 412_STATIC(__after_prom_start) 413#ifdef CONFIG_RELOCATABLE 414 /* process relocations for the final address of the kernel */ 415 lis r25,PAGE_OFFSET@highest /* compute virtual base of kernel */ 416 sldi r25,r25,32 417 lwz r7,__run_at_load-_stext(r26) 418 cmplwi cr0,r7,1 /* flagged to stay where we are ? */ 419 bne 1f 420 add r25,r25,r26 4211: mr r3,r25 422 bl .relocate 423#endif 424 425/* 426 * We need to run with _stext at physical address PHYSICAL_START. 427 * This will leave some code in the first 256B of 428 * real memory, which are reserved for software use. 429 * 430 * Note: This process overwrites the OF exception vectors. 431 */ 432 li r3,0 /* target addr */ 433#ifdef CONFIG_PPC_BOOK3E 434 tovirt(r3,r3) /* on booke, we already run at PAGE_OFFSET */ 435#endif 436 mr. r4,r26 /* In some cases the loader may */ 437 beq 9f /* have already put us at zero */ 438 li r6,0x100 /* Start offset, the first 0x100 */ 439 /* bytes were copied earlier. */ 440#ifdef CONFIG_PPC_BOOK3E 441 tovirt(r6,r6) /* on booke, we already run at PAGE_OFFSET */ 442#endif 443 444#ifdef CONFIG_RELOCATABLE 445/* 446 * Check if the kernel has to be running as relocatable kernel based on the 447 * variable __run_at_load, if it is set the kernel is treated as relocatable 448 * kernel, otherwise it will be moved to PHYSICAL_START 449 */ 450 lwz r7,__run_at_load-_stext(r26) 451 cmplwi cr0,r7,1 452 bne 3f 453 454 /* just copy interrupts */ 455 LOAD_REG_IMMEDIATE(r5, __end_interrupts - _stext) 456 b 5f 4573: 458#endif 459 lis r5,(copy_to_here - _stext)@ha 460 addi r5,r5,(copy_to_here - _stext)@l /* # bytes of memory to copy */ 461 462 bl .copy_and_flush /* copy the first n bytes */ 463 /* this includes the code being */ 464 /* executed here. */ 465 addis r8,r3,(4f - _stext)@ha /* Jump to the copy of this code */ 466 addi r8,r8,(4f - _stext)@l /* that we just made */ 467 mtctr r8 468 bctr 469 470p_end: .llong _end - _stext 471 4724: /* Now copy the rest of the kernel up to _end */ 473 addis r5,r26,(p_end - _stext)@ha 474 ld r5,(p_end - _stext)@l(r5) /* get _end */ 4755: bl .copy_and_flush /* copy the rest */ 476 4779: b .start_here_multiplatform 478 479/* 480 * Copy routine used to copy the kernel to start at physical address 0 481 * and flush and invalidate the caches as needed. 482 * r3 = dest addr, r4 = source addr, r5 = copy limit, r6 = start offset 483 * on exit, r3, r4, r5 are unchanged, r6 is updated to be >= r5. 484 * 485 * Note: this routine *only* clobbers r0, r6 and lr 486 */ 487_GLOBAL(copy_and_flush) 488 addi r5,r5,-8 489 addi r6,r6,-8 4904: li r0,8 /* Use the smallest common */ 491 /* denominator cache line */ 492 /* size. This results in */ 493 /* extra cache line flushes */ 494 /* but operation is correct. */ 495 /* Can't get cache line size */ 496 /* from NACA as it is being */ 497 /* moved too. */ 498 499 mtctr r0 /* put # words/line in ctr */ 5003: addi r6,r6,8 /* copy a cache line */ 501 ldx r0,r6,r4 502 stdx r0,r6,r3 503 bdnz 3b 504 dcbst r6,r3 /* write it to memory */ 505 sync 506 icbi r6,r3 /* flush the icache line */ 507 cmpld 0,r6,r5 508 blt 4b 509 sync 510 addi r5,r5,8 511 addi r6,r6,8 512 blr 513 514.align 8 515copy_to_here: 516 517#ifdef CONFIG_SMP 518#ifdef CONFIG_PPC_PMAC 519/* 520 * On PowerMac, secondary processors starts from the reset vector, which 521 * is temporarily turned into a call to one of the functions below. 522 */ 523 .section ".text"; 524 .align 2 ; 525 526 .globl __secondary_start_pmac_0 527__secondary_start_pmac_0: 528 /* NB the entries for cpus 0, 1, 2 must each occupy 8 bytes. */ 529 li r24,0 530 b 1f 531 li r24,1 532 b 1f 533 li r24,2 534 b 1f 535 li r24,3 5361: 537 538_GLOBAL(pmac_secondary_start) 539 /* turn on 64-bit mode */ 540 bl .enable_64b_mode 541 542 li r0,0 543 mfspr r3,SPRN_HID4 544 rldimi r3,r0,40,23 /* clear bit 23 (rm_ci) */ 545 sync 546 mtspr SPRN_HID4,r3 547 isync 548 sync 549 slbia 550 551 /* get TOC pointer (real address) */ 552 bl .relative_toc 553 tovirt(r2,r2) 554 555 /* Copy some CPU settings from CPU 0 */ 556 bl .__restore_cpu_ppc970 557 558 /* pSeries do that early though I don't think we really need it */ 559 mfmsr r3 560 ori r3,r3,MSR_RI 561 mtmsrd r3 /* RI on */ 562 563 /* Set up a paca value for this processor. */ 564 LOAD_REG_ADDR(r4,paca) /* Load paca pointer */ 565 ld r4,0(r4) /* Get base vaddr of paca array */ 566 mulli r13,r24,PACA_SIZE /* Calculate vaddr of right paca */ 567 add r13,r13,r4 /* for this processor. */ 568 SET_PACA(r13) /* Save vaddr of paca in an SPRG*/ 569 570 /* Mark interrupts soft and hard disabled (they might be enabled 571 * in the PACA when doing hotplug) 572 */ 573 li r0,0 574 stb r0,PACASOFTIRQEN(r13) 575 li r0,PACA_IRQ_HARD_DIS 576 stb r0,PACAIRQHAPPENED(r13) 577 578 /* Create a temp kernel stack for use before relocation is on. */ 579 ld r1,PACAEMERGSP(r13) 580 subi r1,r1,STACK_FRAME_OVERHEAD 581 582 b __secondary_start 583 584#endif /* CONFIG_PPC_PMAC */ 585 586/* 587 * This function is called after the master CPU has released the 588 * secondary processors. The execution environment is relocation off. 589 * The paca for this processor has the following fields initialized at 590 * this point: 591 * 1. Processor number 592 * 2. Segment table pointer (virtual address) 593 * On entry the following are set: 594 * r1 = stack pointer (real addr of temp stack) 595 * r24 = cpu# (in Linux terms) 596 * r13 = paca virtual address 597 * SPRG_PACA = paca virtual address 598 */ 599 .section ".text"; 600 .align 2 ; 601 602 .globl __secondary_start 603__secondary_start: 604 /* Set thread priority to MEDIUM */ 605 HMT_MEDIUM 606 607 /* Initialize the kernel stack */ 608 LOAD_REG_ADDR(r3, current_set) 609 sldi r28,r24,3 /* get current_set[cpu#] */ 610 ldx r14,r3,r28 611 addi r14,r14,THREAD_SIZE-STACK_FRAME_OVERHEAD 612 std r14,PACAKSAVE(r13) 613 614 /* Do early setup for that CPU (stab, slb, hash table pointer) */ 615 bl .early_setup_secondary 616 617 /* 618 * setup the new stack pointer, but *don't* use this until 619 * translation is on. 620 */ 621 mr r1, r14 622 623 /* Clear backchain so we get nice backtraces */ 624 li r7,0 625 mtlr r7 626 627 /* Mark interrupts soft and hard disabled (they might be enabled 628 * in the PACA when doing hotplug) 629 */ 630 stb r7,PACASOFTIRQEN(r13) 631 li r0,PACA_IRQ_HARD_DIS 632 stb r0,PACAIRQHAPPENED(r13) 633 634 /* enable MMU and jump to start_secondary */ 635 LOAD_REG_ADDR(r3, .start_secondary_prolog) 636 LOAD_REG_IMMEDIATE(r4, MSR_KERNEL) 637 638 mtspr SPRN_SRR0,r3 639 mtspr SPRN_SRR1,r4 640 RFI 641 b . /* prevent speculative execution */ 642 643/* 644 * Running with relocation on at this point. All we want to do is 645 * zero the stack back-chain pointer and get the TOC virtual address 646 * before going into C code. 647 */ 648_GLOBAL(start_secondary_prolog) 649 ld r2,PACATOC(r13) 650 li r3,0 651 std r3,0(r1) /* Zero the stack frame pointer */ 652 bl .start_secondary 653 b . 654/* 655 * Reset stack pointer and call start_secondary 656 * to continue with online operation when woken up 657 * from cede in cpu offline. 658 */ 659_GLOBAL(start_secondary_resume) 660 ld r1,PACAKSAVE(r13) /* Reload kernel stack pointer */ 661 li r3,0 662 std r3,0(r1) /* Zero the stack frame pointer */ 663 bl .start_secondary 664 b . 665#endif 666 667/* 668 * This subroutine clobbers r11 and r12 669 */ 670_GLOBAL(enable_64b_mode) 671 mfmsr r11 /* grab the current MSR */ 672#ifdef CONFIG_PPC_BOOK3E 673 oris r11,r11,0x8000 /* CM bit set, we'll set ICM later */ 674 mtmsr r11 675#else /* CONFIG_PPC_BOOK3E */ 676 li r12,(MSR_64BIT | MSR_ISF)@highest 677 sldi r12,r12,48 678 or r11,r11,r12 679 mtmsrd r11 680 isync 681#endif 682 blr 683 684/* 685 * This puts the TOC pointer into r2, offset by 0x8000 (as expected 686 * by the toolchain). It computes the correct value for wherever we 687 * are running at the moment, using position-independent code. 688 * 689 * Note: The compiler constructs pointers using offsets from the 690 * TOC in -mcmodel=medium mode. After we relocate to 0 but before 691 * the MMU is on we need our TOC to be a virtual address otherwise 692 * these pointers will be real addresses which may get stored and 693 * accessed later with the MMU on. We use tovirt() at the call 694 * sites to handle this. 695 */ 696_GLOBAL(relative_toc) 697 mflr r0 698 bcl 20,31,$+4 6990: mflr r11 700 ld r2,(p_toc - 0b)(r11) 701 add r2,r2,r11 702 mtlr r0 703 blr 704 705p_toc: .llong __toc_start + 0x8000 - 0b 706 707/* 708 * This is where the main kernel code starts. 709 */ 710_INIT_STATIC(start_here_multiplatform) 711 /* set up the TOC */ 712 bl .relative_toc 713 tovirt(r2,r2) 714 715 /* Clear out the BSS. It may have been done in prom_init, 716 * already but that's irrelevant since prom_init will soon 717 * be detached from the kernel completely. Besides, we need 718 * to clear it now for kexec-style entry. 719 */ 720 LOAD_REG_ADDR(r11,__bss_stop) 721 LOAD_REG_ADDR(r8,__bss_start) 722 sub r11,r11,r8 /* bss size */ 723 addi r11,r11,7 /* round up to an even double word */ 724 srdi. r11,r11,3 /* shift right by 3 */ 725 beq 4f 726 addi r8,r8,-8 727 li r0,0 728 mtctr r11 /* zero this many doublewords */ 7293: stdu r0,8(r8) 730 bdnz 3b 7314: 732 733#ifdef CONFIG_PPC_EARLY_DEBUG_OPAL 734 /* Setup OPAL entry */ 735 LOAD_REG_ADDR(r11, opal) 736 std r28,0(r11); 737 std r29,8(r11); 738#endif 739 740#ifndef CONFIG_PPC_BOOK3E 741 mfmsr r6 742 ori r6,r6,MSR_RI 743 mtmsrd r6 /* RI on */ 744#endif 745 746#ifdef CONFIG_RELOCATABLE 747 /* Save the physical address we're running at in kernstart_addr */ 748 LOAD_REG_ADDR(r4, kernstart_addr) 749 clrldi r0,r25,2 750 std r0,0(r4) 751#endif 752 753 /* The following gets the stack set up with the regs */ 754 /* pointing to the real addr of the kernel stack. This is */ 755 /* all done to support the C function call below which sets */ 756 /* up the htab. This is done because we have relocated the */ 757 /* kernel but are still running in real mode. */ 758 759 LOAD_REG_ADDR(r3,init_thread_union) 760 761 /* set up a stack pointer */ 762 addi r1,r3,THREAD_SIZE 763 li r0,0 764 stdu r0,-STACK_FRAME_OVERHEAD(r1) 765 766 /* Do very early kernel initializations, including initial hash table, 767 * stab and slb setup before we turn on relocation. */ 768 769 /* Restore parameters passed from prom_init/kexec */ 770 mr r3,r31 771 bl .early_setup /* also sets r13 and SPRG_PACA */ 772 773 LOAD_REG_ADDR(r3, .start_here_common) 774 ld r4,PACAKMSR(r13) 775 mtspr SPRN_SRR0,r3 776 mtspr SPRN_SRR1,r4 777 RFI 778 b . /* prevent speculative execution */ 779 780 /* This is where all platforms converge execution */ 781_INIT_GLOBAL(start_here_common) 782 /* relocation is on at this point */ 783 std r1,PACAKSAVE(r13) 784 785 /* Load the TOC (virtual address) */ 786 ld r2,PACATOC(r13) 787 788 /* Do more system initializations in virtual mode */ 789 bl .setup_system 790 791 /* Mark interrupts soft and hard disabled (they might be enabled 792 * in the PACA when doing hotplug) 793 */ 794 li r0,0 795 stb r0,PACASOFTIRQEN(r13) 796 li r0,PACA_IRQ_HARD_DIS 797 stb r0,PACAIRQHAPPENED(r13) 798 799 /* Generic kernel entry */ 800 bl .start_kernel 801 802 /* Not reached */ 803 BUG_OPCODE 804 805/* 806 * We put a few things here that have to be page-aligned. 807 * This stuff goes at the beginning of the bss, which is page-aligned. 808 */ 809 .section ".bss" 810 811 .align PAGE_SHIFT 812 813 .globl empty_zero_page 814empty_zero_page: 815 .space PAGE_SIZE 816 817 .globl swapper_pg_dir 818swapper_pg_dir: 819 .space PGD_TABLE_SIZE 820