1/* 2 * Kernel execution entry point code. 3 * 4 * Copyright (c) 1995-1996 Gary Thomas <gdt@linuxppc.org> 5 * Initial PowerPC version. 6 * Copyright (c) 1996 Cort Dougan <cort@cs.nmt.edu> 7 * Rewritten for PReP 8 * Copyright (c) 1996 Paul Mackerras <paulus@cs.anu.edu.au> 9 * Low-level exception handers, MMU support, and rewrite. 10 * Copyright (c) 1997 Dan Malek <dmalek@jlc.net> 11 * PowerPC 8xx modifications. 12 * Copyright (c) 1998-1999 TiVo, Inc. 13 * PowerPC 403GCX modifications. 14 * Copyright (c) 1999 Grant Erickson <grant@lcse.umn.edu> 15 * PowerPC 403GCX/405GP modifications. 16 * Copyright 2000 MontaVista Software Inc. 17 * PPC405 modifications 18 * PowerPC 403GCX/405GP modifications. 19 * Author: MontaVista Software, Inc. 20 * frank_rowand@mvista.com or source@mvista.com 21 * debbie_chu@mvista.com 22 * Copyright 2002-2004 MontaVista Software, Inc. 23 * PowerPC 44x support, Matt Porter <mporter@kernel.crashing.org> 24 * Copyright 2004 Freescale Semiconductor, Inc 25 * PowerPC e500 modifications, Kumar Gala <galak@kernel.crashing.org> 26 * 27 * This program is free software; you can redistribute it and/or modify it 28 * under the terms of the GNU General Public License as published by the 29 * Free Software Foundation; either version 2 of the License, or (at your 30 * option) any later version. 31 */ 32 33#include <linux/init.h> 34#include <linux/threads.h> 35#include <asm/processor.h> 36#include <asm/page.h> 37#include <asm/mmu.h> 38#include <asm/pgtable.h> 39#include <asm/cputable.h> 40#include <asm/thread_info.h> 41#include <asm/ppc_asm.h> 42#include <asm/asm-offsets.h> 43#include <asm/cache.h> 44#include <asm/ptrace.h> 45#include <asm/export.h> 46#include <asm/feature-fixups.h> 47#include "head_booke.h" 48 49/* As with the other PowerPC ports, it is expected that when code 50 * execution begins here, the following registers contain valid, yet 51 * optional, information: 52 * 53 * r3 - Board info structure pointer (DRAM, frequency, MAC address, etc.) 54 * r4 - Starting address of the init RAM disk 55 * r5 - Ending address of the init RAM disk 56 * r6 - Start of kernel command line string (e.g. "mem=128") 57 * r7 - End of kernel command line string 58 * 59 */ 60 __HEAD 61_ENTRY(_stext); 62_ENTRY(_start); 63 /* 64 * Reserve a word at a fixed location to store the address 65 * of abatron_pteptrs 66 */ 67 nop 68 69 /* Translate device tree address to physical, save in r30/r31 */ 70 bl get_phys_addr 71 mr r30,r3 72 mr r31,r4 73 74 li r25,0 /* phys kernel start (low) */ 75 li r24,0 /* CPU number */ 76 li r23,0 /* phys kernel start (high) */ 77 78#ifdef CONFIG_RELOCATABLE 79 LOAD_REG_ADDR_PIC(r3, _stext) /* Get our current runtime base */ 80 81 /* Translate _stext address to physical, save in r23/r25 */ 82 bl get_phys_addr 83 mr r23,r3 84 mr r25,r4 85 86 bl 0f 870: mflr r8 88 addis r3,r8,(is_second_reloc - 0b)@ha 89 lwz r19,(is_second_reloc - 0b)@l(r3) 90 91 /* Check if this is the second relocation. */ 92 cmpwi r19,1 93 bne 1f 94 95 /* 96 * For the second relocation, we already get the real memstart_addr 97 * from device tree. So we will map PAGE_OFFSET to memstart_addr, 98 * then the virtual address of start kernel should be: 99 * PAGE_OFFSET + (kernstart_addr - memstart_addr) 100 * Since the offset between kernstart_addr and memstart_addr should 101 * never be beyond 1G, so we can just use the lower 32bit of them 102 * for the calculation. 103 */ 104 lis r3,PAGE_OFFSET@h 105 106 addis r4,r8,(kernstart_addr - 0b)@ha 107 addi r4,r4,(kernstart_addr - 0b)@l 108 lwz r5,4(r4) 109 110 addis r6,r8,(memstart_addr - 0b)@ha 111 addi r6,r6,(memstart_addr - 0b)@l 112 lwz r7,4(r6) 113 114 subf r5,r7,r5 115 add r3,r3,r5 116 b 2f 117 1181: 119 /* 120 * We have the runtime (virutal) address of our base. 121 * We calculate our shift of offset from a 64M page. 122 * We could map the 64M page we belong to at PAGE_OFFSET and 123 * get going from there. 124 */ 125 lis r4,KERNELBASE@h 126 ori r4,r4,KERNELBASE@l 127 rlwinm r6,r25,0,0x3ffffff /* r6 = PHYS_START % 64M */ 128 rlwinm r5,r4,0,0x3ffffff /* r5 = KERNELBASE % 64M */ 129 subf r3,r5,r6 /* r3 = r6 - r5 */ 130 add r3,r4,r3 /* Required Virtual Address */ 131 1322: bl relocate 133 134 /* 135 * For the second relocation, we already set the right tlb entries 136 * for the kernel space, so skip the code in fsl_booke_entry_mapping.S 137 */ 138 cmpwi r19,1 139 beq set_ivor 140#endif 141 142/* We try to not make any assumptions about how the boot loader 143 * setup or used the TLBs. We invalidate all mappings from the 144 * boot loader and load a single entry in TLB1[0] to map the 145 * first 64M of kernel memory. Any boot info passed from the 146 * bootloader needs to live in this first 64M. 147 * 148 * Requirement on bootloader: 149 * - The page we're executing in needs to reside in TLB1 and 150 * have IPROT=1. If not an invalidate broadcast could 151 * evict the entry we're currently executing in. 152 * 153 * r3 = Index of TLB1 were executing in 154 * r4 = Current MSR[IS] 155 * r5 = Index of TLB1 temp mapping 156 * 157 * Later in mapin_ram we will correctly map lowmem, and resize TLB1[0] 158 * if needed 159 */ 160 161_ENTRY(__early_start) 162 163#define ENTRY_MAPPING_BOOT_SETUP 164#include "fsl_booke_entry_mapping.S" 165#undef ENTRY_MAPPING_BOOT_SETUP 166 167set_ivor: 168 /* Establish the interrupt vector offsets */ 169 SET_IVOR(0, CriticalInput); 170 SET_IVOR(1, MachineCheck); 171 SET_IVOR(2, DataStorage); 172 SET_IVOR(3, InstructionStorage); 173 SET_IVOR(4, ExternalInput); 174 SET_IVOR(5, Alignment); 175 SET_IVOR(6, Program); 176 SET_IVOR(7, FloatingPointUnavailable); 177 SET_IVOR(8, SystemCall); 178 SET_IVOR(9, AuxillaryProcessorUnavailable); 179 SET_IVOR(10, Decrementer); 180 SET_IVOR(11, FixedIntervalTimer); 181 SET_IVOR(12, WatchdogTimer); 182 SET_IVOR(13, DataTLBError); 183 SET_IVOR(14, InstructionTLBError); 184 SET_IVOR(15, DebugCrit); 185 186 /* Establish the interrupt vector base */ 187 lis r4,interrupt_base@h /* IVPR only uses the high 16-bits */ 188 mtspr SPRN_IVPR,r4 189 190 /* Setup the defaults for TLB entries */ 191 li r2,(MAS4_TSIZED(BOOK3E_PAGESZ_4K))@l 192#ifdef CONFIG_E200 193 oris r2,r2,MAS4_TLBSELD(1)@h 194#endif 195 mtspr SPRN_MAS4, r2 196 197#if 0 198 /* Enable DOZE */ 199 mfspr r2,SPRN_HID0 200 oris r2,r2,HID0_DOZE@h 201 mtspr SPRN_HID0, r2 202#endif 203 204#if !defined(CONFIG_BDI_SWITCH) 205 /* 206 * The Abatron BDI JTAG debugger does not tolerate others 207 * mucking with the debug registers. 208 */ 209 lis r2,DBCR0_IDM@h 210 mtspr SPRN_DBCR0,r2 211 isync 212 /* clear any residual debug events */ 213 li r2,-1 214 mtspr SPRN_DBSR,r2 215#endif 216 217#ifdef CONFIG_SMP 218 /* Check to see if we're the second processor, and jump 219 * to the secondary_start code if so 220 */ 221 LOAD_REG_ADDR_PIC(r24, boot_cpuid) 222 lwz r24, 0(r24) 223 cmpwi r24, -1 224 mfspr r24,SPRN_PIR 225 bne __secondary_start 226#endif 227 228 /* 229 * This is where the main kernel code starts. 230 */ 231 232 /* ptr to current */ 233 lis r2,init_task@h 234 ori r2,r2,init_task@l 235 236 /* ptr to current thread */ 237 addi r4,r2,THREAD /* init task's THREAD */ 238 mtspr SPRN_SPRG_THREAD,r4 239 240 /* stack */ 241 lis r1,init_thread_union@h 242 ori r1,r1,init_thread_union@l 243 li r0,0 244 stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1) 245 246 CURRENT_THREAD_INFO(r22, r1) 247 stw r24, TI_CPU(r22) 248 249 bl early_init 250 251#ifdef CONFIG_RELOCATABLE 252 mr r3,r30 253 mr r4,r31 254#ifdef CONFIG_PHYS_64BIT 255 mr r5,r23 256 mr r6,r25 257#else 258 mr r5,r25 259#endif 260 bl relocate_init 261#endif 262 263#ifdef CONFIG_DYNAMIC_MEMSTART 264 lis r3,kernstart_addr@ha 265 la r3,kernstart_addr@l(r3) 266#ifdef CONFIG_PHYS_64BIT 267 stw r23,0(r3) 268 stw r25,4(r3) 269#else 270 stw r25,0(r3) 271#endif 272#endif 273 274/* 275 * Decide what sort of machine this is and initialize the MMU. 276 */ 277 mr r3,r30 278 mr r4,r31 279 bl machine_init 280 bl MMU_init 281 282 /* Setup PTE pointers for the Abatron bdiGDB */ 283 lis r6, swapper_pg_dir@h 284 ori r6, r6, swapper_pg_dir@l 285 lis r5, abatron_pteptrs@h 286 ori r5, r5, abatron_pteptrs@l 287 lis r4, KERNELBASE@h 288 ori r4, r4, KERNELBASE@l 289 stw r5, 0(r4) /* Save abatron_pteptrs at a fixed location */ 290 stw r6, 0(r5) 291 292 /* Let's move on */ 293 lis r4,start_kernel@h 294 ori r4,r4,start_kernel@l 295 lis r3,MSR_KERNEL@h 296 ori r3,r3,MSR_KERNEL@l 297 mtspr SPRN_SRR0,r4 298 mtspr SPRN_SRR1,r3 299 rfi /* change context and jump to start_kernel */ 300 301/* Macros to hide the PTE size differences 302 * 303 * FIND_PTE -- walks the page tables given EA & pgdir pointer 304 * r10 -- EA of fault 305 * r11 -- PGDIR pointer 306 * r12 -- free 307 * label 2: is the bailout case 308 * 309 * if we find the pte (fall through): 310 * r11 is low pte word 311 * r12 is pointer to the pte 312 * r10 is the pshift from the PGD, if we're a hugepage 313 */ 314#ifdef CONFIG_PTE_64BIT 315#ifdef CONFIG_HUGETLB_PAGE 316#define FIND_PTE \ 317 rlwinm r12, r10, 13, 19, 29; /* Compute pgdir/pmd offset */ \ 318 lwzx r11, r12, r11; /* Get pgd/pmd entry */ \ 319 rlwinm. r12, r11, 0, 0, 20; /* Extract pt base address */ \ 320 blt 1000f; /* Normal non-huge page */ \ 321 beq 2f; /* Bail if no table */ \ 322 oris r11, r11, PD_HUGE@h; /* Put back address bit */ \ 323 andi. r10, r11, HUGEPD_SHIFT_MASK@l; /* extract size field */ \ 324 xor r12, r10, r11; /* drop size bits from pointer */ \ 325 b 1001f; \ 3261000: rlwimi r12, r10, 23, 20, 28; /* Compute pte address */ \ 327 li r10, 0; /* clear r10 */ \ 3281001: lwz r11, 4(r12); /* Get pte entry */ 329#else 330#define FIND_PTE \ 331 rlwinm r12, r10, 13, 19, 29; /* Compute pgdir/pmd offset */ \ 332 lwzx r11, r12, r11; /* Get pgd/pmd entry */ \ 333 rlwinm. r12, r11, 0, 0, 20; /* Extract pt base address */ \ 334 beq 2f; /* Bail if no table */ \ 335 rlwimi r12, r10, 23, 20, 28; /* Compute pte address */ \ 336 lwz r11, 4(r12); /* Get pte entry */ 337#endif /* HUGEPAGE */ 338#else /* !PTE_64BIT */ 339#define FIND_PTE \ 340 rlwimi r11, r10, 12, 20, 29; /* Create L1 (pgdir/pmd) address */ \ 341 lwz r11, 0(r11); /* Get L1 entry */ \ 342 rlwinm. r12, r11, 0, 0, 19; /* Extract L2 (pte) base address */ \ 343 beq 2f; /* Bail if no table */ \ 344 rlwimi r12, r10, 22, 20, 29; /* Compute PTE address */ \ 345 lwz r11, 0(r12); /* Get Linux PTE */ 346#endif 347 348/* 349 * Interrupt vector entry code 350 * 351 * The Book E MMUs are always on so we don't need to handle 352 * interrupts in real mode as with previous PPC processors. In 353 * this case we handle interrupts in the kernel virtual address 354 * space. 355 * 356 * Interrupt vectors are dynamically placed relative to the 357 * interrupt prefix as determined by the address of interrupt_base. 358 * The interrupt vectors offsets are programmed using the labels 359 * for each interrupt vector entry. 360 * 361 * Interrupt vectors must be aligned on a 16 byte boundary. 362 * We align on a 32 byte cache line boundary for good measure. 363 */ 364 365interrupt_base: 366 /* Critical Input Interrupt */ 367 CRITICAL_EXCEPTION(0x0100, CRITICAL, CriticalInput, unknown_exception) 368 369 /* Machine Check Interrupt */ 370#ifdef CONFIG_E200 371 /* no RFMCI, MCSRRs on E200 */ 372 CRITICAL_EXCEPTION(0x0200, MACHINE_CHECK, MachineCheck, \ 373 machine_check_exception) 374#else 375 MCHECK_EXCEPTION(0x0200, MachineCheck, machine_check_exception) 376#endif 377 378 /* Data Storage Interrupt */ 379 START_EXCEPTION(DataStorage) 380 NORMAL_EXCEPTION_PROLOG(DATA_STORAGE) 381 mfspr r5,SPRN_ESR /* Grab the ESR, save it, pass arg3 */ 382 stw r5,_ESR(r11) 383 mfspr r4,SPRN_DEAR /* Grab the DEAR, save it, pass arg2 */ 384 andis. r10,r5,(ESR_ILK|ESR_DLK)@h 385 bne 1f 386 EXC_XFER_LITE(0x0300, handle_page_fault) 3871: 388 addi r3,r1,STACK_FRAME_OVERHEAD 389 EXC_XFER_EE_LITE(0x0300, CacheLockingException) 390 391 /* Instruction Storage Interrupt */ 392 INSTRUCTION_STORAGE_EXCEPTION 393 394 /* External Input Interrupt */ 395 EXCEPTION(0x0500, EXTERNAL, ExternalInput, do_IRQ, EXC_XFER_LITE) 396 397 /* Alignment Interrupt */ 398 ALIGNMENT_EXCEPTION 399 400 /* Program Interrupt */ 401 PROGRAM_EXCEPTION 402 403 /* Floating Point Unavailable Interrupt */ 404#ifdef CONFIG_PPC_FPU 405 FP_UNAVAILABLE_EXCEPTION 406#else 407#ifdef CONFIG_E200 408 /* E200 treats 'normal' floating point instructions as FP Unavail exception */ 409 EXCEPTION(0x0800, FP_UNAVAIL, FloatingPointUnavailable, \ 410 program_check_exception, EXC_XFER_EE) 411#else 412 EXCEPTION(0x0800, FP_UNAVAIL, FloatingPointUnavailable, \ 413 unknown_exception, EXC_XFER_EE) 414#endif 415#endif 416 417 /* System Call Interrupt */ 418 START_EXCEPTION(SystemCall) 419 NORMAL_EXCEPTION_PROLOG(SYSCALL) 420 EXC_XFER_EE_LITE(0x0c00, DoSyscall) 421 422 /* Auxiliary Processor Unavailable Interrupt */ 423 EXCEPTION(0x2900, AP_UNAVAIL, AuxillaryProcessorUnavailable, \ 424 unknown_exception, EXC_XFER_EE) 425 426 /* Decrementer Interrupt */ 427 DECREMENTER_EXCEPTION 428 429 /* Fixed Internal Timer Interrupt */ 430 /* TODO: Add FIT support */ 431 EXCEPTION(0x3100, FIT, FixedIntervalTimer, \ 432 unknown_exception, EXC_XFER_EE) 433 434 /* Watchdog Timer Interrupt */ 435#ifdef CONFIG_BOOKE_WDT 436 CRITICAL_EXCEPTION(0x3200, WATCHDOG, WatchdogTimer, WatchdogException) 437#else 438 CRITICAL_EXCEPTION(0x3200, WATCHDOG, WatchdogTimer, unknown_exception) 439#endif 440 441 /* Data TLB Error Interrupt */ 442 START_EXCEPTION(DataTLBError) 443 mtspr SPRN_SPRG_WSCRATCH0, r10 /* Save some working registers */ 444 mfspr r10, SPRN_SPRG_THREAD 445 stw r11, THREAD_NORMSAVE(0)(r10) 446#ifdef CONFIG_KVM_BOOKE_HV 447BEGIN_FTR_SECTION 448 mfspr r11, SPRN_SRR1 449END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV) 450#endif 451 stw r12, THREAD_NORMSAVE(1)(r10) 452 stw r13, THREAD_NORMSAVE(2)(r10) 453 mfcr r13 454 stw r13, THREAD_NORMSAVE(3)(r10) 455 DO_KVM BOOKE_INTERRUPT_DTLB_MISS SPRN_SRR1 456 mfspr r10, SPRN_DEAR /* Get faulting address */ 457 458 /* If we are faulting a kernel address, we have to use the 459 * kernel page tables. 460 */ 461 lis r11, PAGE_OFFSET@h 462 cmplw 5, r10, r11 463 blt 5, 3f 464 lis r11, swapper_pg_dir@h 465 ori r11, r11, swapper_pg_dir@l 466 467 mfspr r12,SPRN_MAS1 /* Set TID to 0 */ 468 rlwinm r12,r12,0,16,1 469 mtspr SPRN_MAS1,r12 470 471 b 4f 472 473 /* Get the PGD for the current thread */ 4743: 475 mfspr r11,SPRN_SPRG_THREAD 476 lwz r11,PGDIR(r11) 477 4784: 479 /* Mask of required permission bits. Note that while we 480 * do copy ESR:ST to _PAGE_RW position as trying to write 481 * to an RO page is pretty common, we don't do it with 482 * _PAGE_DIRTY. We could do it, but it's a fairly rare 483 * event so I'd rather take the overhead when it happens 484 * rather than adding an instruction here. We should measure 485 * whether the whole thing is worth it in the first place 486 * as we could avoid loading SPRN_ESR completely in the first 487 * place... 488 * 489 * TODO: Is it worth doing that mfspr & rlwimi in the first 490 * place or can we save a couple of instructions here ? 491 */ 492 mfspr r12,SPRN_ESR 493#ifdef CONFIG_PTE_64BIT 494 li r13,_PAGE_PRESENT 495 oris r13,r13,_PAGE_ACCESSED@h 496#else 497 li r13,_PAGE_PRESENT|_PAGE_ACCESSED 498#endif 499 rlwimi r13,r12,11,29,29 500 501 FIND_PTE 502 andc. r13,r13,r11 /* Check permission */ 503 504#ifdef CONFIG_PTE_64BIT 505#ifdef CONFIG_SMP 506 subf r13,r11,r12 /* create false data dep */ 507 lwzx r13,r11,r13 /* Get upper pte bits */ 508#else 509 lwz r13,0(r12) /* Get upper pte bits */ 510#endif 511#endif 512 513 bne 2f /* Bail if permission/valid mismach */ 514 515 /* Jump to common tlb load */ 516 b finish_tlb_load 5172: 518 /* The bailout. Restore registers to pre-exception conditions 519 * and call the heavyweights to help us out. 520 */ 521 mfspr r10, SPRN_SPRG_THREAD 522 lwz r11, THREAD_NORMSAVE(3)(r10) 523 mtcr r11 524 lwz r13, THREAD_NORMSAVE(2)(r10) 525 lwz r12, THREAD_NORMSAVE(1)(r10) 526 lwz r11, THREAD_NORMSAVE(0)(r10) 527 mfspr r10, SPRN_SPRG_RSCRATCH0 528 b DataStorage 529 530 /* Instruction TLB Error Interrupt */ 531 /* 532 * Nearly the same as above, except we get our 533 * information from different registers and bailout 534 * to a different point. 535 */ 536 START_EXCEPTION(InstructionTLBError) 537 mtspr SPRN_SPRG_WSCRATCH0, r10 /* Save some working registers */ 538 mfspr r10, SPRN_SPRG_THREAD 539 stw r11, THREAD_NORMSAVE(0)(r10) 540#ifdef CONFIG_KVM_BOOKE_HV 541BEGIN_FTR_SECTION 542 mfspr r11, SPRN_SRR1 543END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV) 544#endif 545 stw r12, THREAD_NORMSAVE(1)(r10) 546 stw r13, THREAD_NORMSAVE(2)(r10) 547 mfcr r13 548 stw r13, THREAD_NORMSAVE(3)(r10) 549 DO_KVM BOOKE_INTERRUPT_ITLB_MISS SPRN_SRR1 550 mfspr r10, SPRN_SRR0 /* Get faulting address */ 551 552 /* If we are faulting a kernel address, we have to use the 553 * kernel page tables. 554 */ 555 lis r11, PAGE_OFFSET@h 556 cmplw 5, r10, r11 557 blt 5, 3f 558 lis r11, swapper_pg_dir@h 559 ori r11, r11, swapper_pg_dir@l 560 561 mfspr r12,SPRN_MAS1 /* Set TID to 0 */ 562 rlwinm r12,r12,0,16,1 563 mtspr SPRN_MAS1,r12 564 565 /* Make up the required permissions for kernel code */ 566#ifdef CONFIG_PTE_64BIT 567 li r13,_PAGE_PRESENT | _PAGE_BAP_SX 568 oris r13,r13,_PAGE_ACCESSED@h 569#else 570 li r13,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC 571#endif 572 b 4f 573 574 /* Get the PGD for the current thread */ 5753: 576 mfspr r11,SPRN_SPRG_THREAD 577 lwz r11,PGDIR(r11) 578 579 /* Make up the required permissions for user code */ 580#ifdef CONFIG_PTE_64BIT 581 li r13,_PAGE_PRESENT | _PAGE_BAP_UX 582 oris r13,r13,_PAGE_ACCESSED@h 583#else 584 li r13,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC 585#endif 586 5874: 588 FIND_PTE 589 andc. r13,r13,r11 /* Check permission */ 590 591#ifdef CONFIG_PTE_64BIT 592#ifdef CONFIG_SMP 593 subf r13,r11,r12 /* create false data dep */ 594 lwzx r13,r11,r13 /* Get upper pte bits */ 595#else 596 lwz r13,0(r12) /* Get upper pte bits */ 597#endif 598#endif 599 600 bne 2f /* Bail if permission mismach */ 601 602 /* Jump to common TLB load point */ 603 b finish_tlb_load 604 6052: 606 /* The bailout. Restore registers to pre-exception conditions 607 * and call the heavyweights to help us out. 608 */ 609 mfspr r10, SPRN_SPRG_THREAD 610 lwz r11, THREAD_NORMSAVE(3)(r10) 611 mtcr r11 612 lwz r13, THREAD_NORMSAVE(2)(r10) 613 lwz r12, THREAD_NORMSAVE(1)(r10) 614 lwz r11, THREAD_NORMSAVE(0)(r10) 615 mfspr r10, SPRN_SPRG_RSCRATCH0 616 b InstructionStorage 617 618/* Define SPE handlers for e200 and e500v2 */ 619#ifdef CONFIG_SPE 620 /* SPE Unavailable */ 621 START_EXCEPTION(SPEUnavailable) 622 NORMAL_EXCEPTION_PROLOG(SPE_UNAVAIL) 623 beq 1f 624 bl load_up_spe 625 b fast_exception_return 6261: addi r3,r1,STACK_FRAME_OVERHEAD 627 EXC_XFER_EE_LITE(0x2010, KernelSPE) 628#elif defined(CONFIG_SPE_POSSIBLE) 629 EXCEPTION(0x2020, SPE_UNAVAIL, SPEUnavailable, \ 630 unknown_exception, EXC_XFER_EE) 631#endif /* CONFIG_SPE_POSSIBLE */ 632 633 /* SPE Floating Point Data */ 634#ifdef CONFIG_SPE 635 EXCEPTION(0x2030, SPE_FP_DATA, SPEFloatingPointData, 636 SPEFloatingPointException, EXC_XFER_EE) 637 638 /* SPE Floating Point Round */ 639 EXCEPTION(0x2050, SPE_FP_ROUND, SPEFloatingPointRound, \ 640 SPEFloatingPointRoundException, EXC_XFER_EE) 641#elif defined(CONFIG_SPE_POSSIBLE) 642 EXCEPTION(0x2040, SPE_FP_DATA, SPEFloatingPointData, 643 unknown_exception, EXC_XFER_EE) 644 EXCEPTION(0x2050, SPE_FP_ROUND, SPEFloatingPointRound, \ 645 unknown_exception, EXC_XFER_EE) 646#endif /* CONFIG_SPE_POSSIBLE */ 647 648 649 /* Performance Monitor */ 650 EXCEPTION(0x2060, PERFORMANCE_MONITOR, PerformanceMonitor, \ 651 performance_monitor_exception, EXC_XFER_STD) 652 653 EXCEPTION(0x2070, DOORBELL, Doorbell, doorbell_exception, EXC_XFER_STD) 654 655 CRITICAL_EXCEPTION(0x2080, DOORBELL_CRITICAL, \ 656 CriticalDoorbell, unknown_exception) 657 658 /* Debug Interrupt */ 659 DEBUG_DEBUG_EXCEPTION 660 DEBUG_CRIT_EXCEPTION 661 662 GUEST_DOORBELL_EXCEPTION 663 664 CRITICAL_EXCEPTION(0, GUEST_DBELL_CRIT, CriticalGuestDoorbell, \ 665 unknown_exception) 666 667 /* Hypercall */ 668 EXCEPTION(0, HV_SYSCALL, Hypercall, unknown_exception, EXC_XFER_EE) 669 670 /* Embedded Hypervisor Privilege */ 671 EXCEPTION(0, HV_PRIV, Ehvpriv, unknown_exception, EXC_XFER_EE) 672 673interrupt_end: 674 675/* 676 * Local functions 677 */ 678 679/* 680 * Both the instruction and data TLB miss get to this 681 * point to load the TLB. 682 * r10 - tsize encoding (if HUGETLB_PAGE) or available to use 683 * r11 - TLB (info from Linux PTE) 684 * r12 - available to use 685 * r13 - upper bits of PTE (if PTE_64BIT) or available to use 686 * CR5 - results of addr >= PAGE_OFFSET 687 * MAS0, MAS1 - loaded with proper value when we get here 688 * MAS2, MAS3 - will need additional info from Linux PTE 689 * Upon exit, we reload everything and RFI. 690 */ 691finish_tlb_load: 692#ifdef CONFIG_HUGETLB_PAGE 693 cmpwi 6, r10, 0 /* check for huge page */ 694 beq 6, finish_tlb_load_cont /* !huge */ 695 696 /* Alas, we need more scratch registers for hugepages */ 697 mfspr r12, SPRN_SPRG_THREAD 698 stw r14, THREAD_NORMSAVE(4)(r12) 699 stw r15, THREAD_NORMSAVE(5)(r12) 700 stw r16, THREAD_NORMSAVE(6)(r12) 701 stw r17, THREAD_NORMSAVE(7)(r12) 702 703 /* Get the next_tlbcam_idx percpu var */ 704#ifdef CONFIG_SMP 705 lwz r12, THREAD_INFO-THREAD(r12) 706 lwz r15, TI_CPU(r12) 707 lis r14, __per_cpu_offset@h 708 ori r14, r14, __per_cpu_offset@l 709 rlwinm r15, r15, 2, 0, 29 710 lwzx r16, r14, r15 711#else 712 li r16, 0 713#endif 714 lis r17, next_tlbcam_idx@h 715 ori r17, r17, next_tlbcam_idx@l 716 add r17, r17, r16 /* r17 = *next_tlbcam_idx */ 717 lwz r15, 0(r17) /* r15 = next_tlbcam_idx */ 718 719 lis r14, MAS0_TLBSEL(1)@h /* select TLB1 (TLBCAM) */ 720 rlwimi r14, r15, 16, 4, 15 /* next_tlbcam_idx entry */ 721 mtspr SPRN_MAS0, r14 722 723 /* Extract TLB1CFG(NENTRY) */ 724 mfspr r16, SPRN_TLB1CFG 725 andi. r16, r16, 0xfff 726 727 /* Update next_tlbcam_idx, wrapping when necessary */ 728 addi r15, r15, 1 729 cmpw r15, r16 730 blt 100f 731 lis r14, tlbcam_index@h 732 ori r14, r14, tlbcam_index@l 733 lwz r15, 0(r14) 734100: stw r15, 0(r17) 735 736 /* 737 * Calc MAS1_TSIZE from r10 (which has pshift encoded) 738 * tlb_enc = (pshift - 10). 739 */ 740 subi r15, r10, 10 741 mfspr r16, SPRN_MAS1 742 rlwimi r16, r15, 7, 20, 24 743 mtspr SPRN_MAS1, r16 744 745 /* copy the pshift for use later */ 746 mr r14, r10 747 748 /* fall through */ 749 750#endif /* CONFIG_HUGETLB_PAGE */ 751 752 /* 753 * We set execute, because we don't have the granularity to 754 * properly set this at the page level (Linux problem). 755 * Many of these bits are software only. Bits we don't set 756 * here we (properly should) assume have the appropriate value. 757 */ 758finish_tlb_load_cont: 759#ifdef CONFIG_PTE_64BIT 760 rlwinm r12, r11, 32-2, 26, 31 /* Move in perm bits */ 761 andi. r10, r11, _PAGE_DIRTY 762 bne 1f 763 li r10, MAS3_SW | MAS3_UW 764 andc r12, r12, r10 7651: rlwimi r12, r13, 20, 0, 11 /* grab RPN[32:43] */ 766 rlwimi r12, r11, 20, 12, 19 /* grab RPN[44:51] */ 7672: mtspr SPRN_MAS3, r12 768BEGIN_MMU_FTR_SECTION 769 srwi r10, r13, 12 /* grab RPN[12:31] */ 770 mtspr SPRN_MAS7, r10 771END_MMU_FTR_SECTION_IFSET(MMU_FTR_BIG_PHYS) 772#else 773 li r10, (_PAGE_EXEC | _PAGE_PRESENT) 774 mr r13, r11 775 rlwimi r10, r11, 31, 29, 29 /* extract _PAGE_DIRTY into SW */ 776 and r12, r11, r10 777 andi. r10, r11, _PAGE_USER /* Test for _PAGE_USER */ 778 slwi r10, r12, 1 779 or r10, r10, r12 780 iseleq r12, r12, r10 781 rlwimi r13, r12, 0, 20, 31 /* Get RPN from PTE, merge w/ perms */ 782 mtspr SPRN_MAS3, r13 783#endif 784 785 mfspr r12, SPRN_MAS2 786#ifdef CONFIG_PTE_64BIT 787 rlwimi r12, r11, 32-19, 27, 31 /* extract WIMGE from pte */ 788#else 789 rlwimi r12, r11, 26, 27, 31 /* extract WIMGE from pte */ 790#endif 791#ifdef CONFIG_HUGETLB_PAGE 792 beq 6, 3f /* don't mask if page isn't huge */ 793 li r13, 1 794 slw r13, r13, r14 795 subi r13, r13, 1 796 rlwinm r13, r13, 0, 0, 19 /* bottom bits used for WIMGE/etc */ 797 andc r12, r12, r13 /* mask off ea bits within the page */ 798#endif 7993: mtspr SPRN_MAS2, r12 800 801#ifdef CONFIG_E200 802 /* Round robin TLB1 entries assignment */ 803 mfspr r12, SPRN_MAS0 804 805 /* Extract TLB1CFG(NENTRY) */ 806 mfspr r11, SPRN_TLB1CFG 807 andi. r11, r11, 0xfff 808 809 /* Extract MAS0(NV) */ 810 andi. r13, r12, 0xfff 811 addi r13, r13, 1 812 cmpw 0, r13, r11 813 addi r12, r12, 1 814 815 /* check if we need to wrap */ 816 blt 7f 817 818 /* wrap back to first free tlbcam entry */ 819 lis r13, tlbcam_index@ha 820 lwz r13, tlbcam_index@l(r13) 821 rlwimi r12, r13, 0, 20, 31 8227: 823 mtspr SPRN_MAS0,r12 824#endif /* CONFIG_E200 */ 825 826tlb_write_entry: 827 tlbwe 828 829 /* Done...restore registers and get out of here. */ 830 mfspr r10, SPRN_SPRG_THREAD 831#ifdef CONFIG_HUGETLB_PAGE 832 beq 6, 8f /* skip restore for 4k page faults */ 833 lwz r14, THREAD_NORMSAVE(4)(r10) 834 lwz r15, THREAD_NORMSAVE(5)(r10) 835 lwz r16, THREAD_NORMSAVE(6)(r10) 836 lwz r17, THREAD_NORMSAVE(7)(r10) 837#endif 8388: lwz r11, THREAD_NORMSAVE(3)(r10) 839 mtcr r11 840 lwz r13, THREAD_NORMSAVE(2)(r10) 841 lwz r12, THREAD_NORMSAVE(1)(r10) 842 lwz r11, THREAD_NORMSAVE(0)(r10) 843 mfspr r10, SPRN_SPRG_RSCRATCH0 844 rfi /* Force context change */ 845 846#ifdef CONFIG_SPE 847/* Note that the SPE support is closely modeled after the AltiVec 848 * support. Changes to one are likely to be applicable to the 849 * other! */ 850_GLOBAL(load_up_spe) 851/* 852 * Disable SPE for the task which had SPE previously, 853 * and save its SPE registers in its thread_struct. 854 * Enables SPE for use in the kernel on return. 855 * On SMP we know the SPE units are free, since we give it up every 856 * switch. -- Kumar 857 */ 858 mfmsr r5 859 oris r5,r5,MSR_SPE@h 860 mtmsr r5 /* enable use of SPE now */ 861 isync 862 /* enable use of SPE after return */ 863 oris r9,r9,MSR_SPE@h 864 mfspr r5,SPRN_SPRG_THREAD /* current task's THREAD (phys) */ 865 li r4,1 866 li r10,THREAD_ACC 867 stw r4,THREAD_USED_SPE(r5) 868 evlddx evr4,r10,r5 869 evmra evr4,evr4 870 REST_32EVRS(0,r10,r5,THREAD_EVR0) 871 blr 872 873/* 874 * SPE unavailable trap from kernel - print a message, but let 875 * the task use SPE in the kernel until it returns to user mode. 876 */ 877KernelSPE: 878 lwz r3,_MSR(r1) 879 oris r3,r3,MSR_SPE@h 880 stw r3,_MSR(r1) /* enable use of SPE after return */ 881#ifdef CONFIG_PRINTK 882 lis r3,87f@h 883 ori r3,r3,87f@l 884 mr r4,r2 /* current */ 885 lwz r5,_NIP(r1) 886 bl printk 887#endif 888 b ret_from_except 889#ifdef CONFIG_PRINTK 89087: .string "SPE used in kernel (task=%p, pc=%x) \n" 891#endif 892 .align 4,0 893 894#endif /* CONFIG_SPE */ 895 896/* 897 * Translate the effec addr in r3 to phys addr. The phys addr will be put 898 * into r3(higher 32bit) and r4(lower 32bit) 899 */ 900get_phys_addr: 901 mfmsr r8 902 mfspr r9,SPRN_PID 903 rlwinm r9,r9,16,0x3fff0000 /* turn PID into MAS6[SPID] */ 904 rlwimi r9,r8,28,0x00000001 /* turn MSR[DS] into MAS6[SAS] */ 905 mtspr SPRN_MAS6,r9 906 907 tlbsx 0,r3 /* must succeed */ 908 909 mfspr r8,SPRN_MAS1 910 mfspr r12,SPRN_MAS3 911 rlwinm r9,r8,25,0x1f /* r9 = log2(page size) */ 912 li r10,1024 913 slw r10,r10,r9 /* r10 = page size */ 914 addi r10,r10,-1 915 and r11,r3,r10 /* r11 = page offset */ 916 andc r4,r12,r10 /* r4 = page base */ 917 or r4,r4,r11 /* r4 = devtree phys addr */ 918#ifdef CONFIG_PHYS_64BIT 919 mfspr r3,SPRN_MAS7 920#endif 921 blr 922 923/* 924 * Global functions 925 */ 926 927#ifdef CONFIG_E200 928/* Adjust or setup IVORs for e200 */ 929_GLOBAL(__setup_e200_ivors) 930 li r3,DebugDebug@l 931 mtspr SPRN_IVOR15,r3 932 li r3,SPEUnavailable@l 933 mtspr SPRN_IVOR32,r3 934 li r3,SPEFloatingPointData@l 935 mtspr SPRN_IVOR33,r3 936 li r3,SPEFloatingPointRound@l 937 mtspr SPRN_IVOR34,r3 938 sync 939 blr 940#endif 941 942#ifdef CONFIG_E500 943#ifndef CONFIG_PPC_E500MC 944/* Adjust or setup IVORs for e500v1/v2 */ 945_GLOBAL(__setup_e500_ivors) 946 li r3,DebugCrit@l 947 mtspr SPRN_IVOR15,r3 948 li r3,SPEUnavailable@l 949 mtspr SPRN_IVOR32,r3 950 li r3,SPEFloatingPointData@l 951 mtspr SPRN_IVOR33,r3 952 li r3,SPEFloatingPointRound@l 953 mtspr SPRN_IVOR34,r3 954 li r3,PerformanceMonitor@l 955 mtspr SPRN_IVOR35,r3 956 sync 957 blr 958#else 959/* Adjust or setup IVORs for e500mc */ 960_GLOBAL(__setup_e500mc_ivors) 961 li r3,DebugDebug@l 962 mtspr SPRN_IVOR15,r3 963 li r3,PerformanceMonitor@l 964 mtspr SPRN_IVOR35,r3 965 li r3,Doorbell@l 966 mtspr SPRN_IVOR36,r3 967 li r3,CriticalDoorbell@l 968 mtspr SPRN_IVOR37,r3 969 sync 970 blr 971 972/* setup ehv ivors for */ 973_GLOBAL(__setup_ehv_ivors) 974 li r3,GuestDoorbell@l 975 mtspr SPRN_IVOR38,r3 976 li r3,CriticalGuestDoorbell@l 977 mtspr SPRN_IVOR39,r3 978 li r3,Hypercall@l 979 mtspr SPRN_IVOR40,r3 980 li r3,Ehvpriv@l 981 mtspr SPRN_IVOR41,r3 982 sync 983 blr 984#endif /* CONFIG_PPC_E500MC */ 985#endif /* CONFIG_E500 */ 986 987#ifdef CONFIG_SPE 988/* 989 * extern void __giveup_spe(struct task_struct *prev) 990 * 991 */ 992_GLOBAL(__giveup_spe) 993 addi r3,r3,THREAD /* want THREAD of task */ 994 lwz r5,PT_REGS(r3) 995 cmpi 0,r5,0 996 SAVE_32EVRS(0, r4, r3, THREAD_EVR0) 997 evxor evr6, evr6, evr6 /* clear out evr6 */ 998 evmwumiaa evr6, evr6, evr6 /* evr6 <- ACC = 0 * 0 + ACC */ 999 li r4,THREAD_ACC 1000 evstddx evr6, r4, r3 /* save off accumulator */ 1001 beq 1f 1002 lwz r4,_MSR-STACK_FRAME_OVERHEAD(r5) 1003 lis r3,MSR_SPE@h 1004 andc r4,r4,r3 /* disable SPE for previous task */ 1005 stw r4,_MSR-STACK_FRAME_OVERHEAD(r5) 10061: 1007 blr 1008#endif /* CONFIG_SPE */ 1009 1010/* 1011 * extern void abort(void) 1012 * 1013 * At present, this routine just applies a system reset. 1014 */ 1015_GLOBAL(abort) 1016 li r13,0 1017 mtspr SPRN_DBCR0,r13 /* disable all debug events */ 1018 isync 1019 mfmsr r13 1020 ori r13,r13,MSR_DE@l /* Enable Debug Events */ 1021 mtmsr r13 1022 isync 1023 mfspr r13,SPRN_DBCR0 1024 lis r13,(DBCR0_IDM|DBCR0_RST_CHIP)@h 1025 mtspr SPRN_DBCR0,r13 1026 isync 1027 1028_GLOBAL(set_context) 1029 1030#ifdef CONFIG_BDI_SWITCH 1031 /* Context switch the PTE pointer for the Abatron BDI2000. 1032 * The PGDIR is the second parameter. 1033 */ 1034 lis r5, abatron_pteptrs@h 1035 ori r5, r5, abatron_pteptrs@l 1036 stw r4, 0x4(r5) 1037#endif 1038 mtspr SPRN_PID,r3 1039 isync /* Force context change */ 1040 blr 1041 1042#ifdef CONFIG_SMP 1043/* When we get here, r24 needs to hold the CPU # */ 1044 .globl __secondary_start 1045__secondary_start: 1046 LOAD_REG_ADDR_PIC(r3, tlbcam_index) 1047 lwz r3,0(r3) 1048 mtctr r3 1049 li r26,0 /* r26 safe? */ 1050 1051 bl switch_to_as1 1052 mr r27,r3 /* tlb entry */ 1053 /* Load each CAM entry */ 10541: mr r3,r26 1055 bl loadcam_entry 1056 addi r26,r26,1 1057 bdnz 1b 1058 mr r3,r27 /* tlb entry */ 1059 LOAD_REG_ADDR_PIC(r4, memstart_addr) 1060 lwz r4,0(r4) 1061 mr r5,r25 /* phys kernel start */ 1062 rlwinm r5,r5,0,~0x3ffffff /* aligned 64M */ 1063 subf r4,r5,r4 /* memstart_addr - phys kernel start */ 1064 li r5,0 /* no device tree */ 1065 li r6,0 /* not boot cpu */ 1066 bl restore_to_as0 1067 1068 1069 lis r3,__secondary_hold_acknowledge@h 1070 ori r3,r3,__secondary_hold_acknowledge@l 1071 stw r24,0(r3) 1072 1073 li r3,0 1074 mr r4,r24 /* Why? */ 1075 bl call_setup_cpu 1076 1077 /* get current_thread_info and current */ 1078 lis r1,secondary_ti@ha 1079 lwz r1,secondary_ti@l(r1) 1080 lwz r2,TI_TASK(r1) 1081 1082 /* stack */ 1083 addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD 1084 li r0,0 1085 stw r0,0(r1) 1086 1087 /* ptr to current thread */ 1088 addi r4,r2,THREAD /* address of our thread_struct */ 1089 mtspr SPRN_SPRG_THREAD,r4 1090 1091 /* Setup the defaults for TLB entries */ 1092 li r4,(MAS4_TSIZED(BOOK3E_PAGESZ_4K))@l 1093 mtspr SPRN_MAS4,r4 1094 1095 /* Jump to start_secondary */ 1096 lis r4,MSR_KERNEL@h 1097 ori r4,r4,MSR_KERNEL@l 1098 lis r3,start_secondary@h 1099 ori r3,r3,start_secondary@l 1100 mtspr SPRN_SRR0,r3 1101 mtspr SPRN_SRR1,r4 1102 sync 1103 rfi 1104 sync 1105 1106 .globl __secondary_hold_acknowledge 1107__secondary_hold_acknowledge: 1108 .long -1 1109#endif 1110 1111/* 1112 * Create a tlb entry with the same effective and physical address as 1113 * the tlb entry used by the current running code. But set the TS to 1. 1114 * Then switch to the address space 1. It will return with the r3 set to 1115 * the ESEL of the new created tlb. 1116 */ 1117_GLOBAL(switch_to_as1) 1118 mflr r5 1119 1120 /* Find a entry not used */ 1121 mfspr r3,SPRN_TLB1CFG 1122 andi. r3,r3,0xfff 1123 mfspr r4,SPRN_PID 1124 rlwinm r4,r4,16,0x3fff0000 /* turn PID into MAS6[SPID] */ 1125 mtspr SPRN_MAS6,r4 11261: lis r4,0x1000 /* Set MAS0(TLBSEL) = 1 */ 1127 addi r3,r3,-1 1128 rlwimi r4,r3,16,4,15 /* Setup MAS0 = TLBSEL | ESEL(r3) */ 1129 mtspr SPRN_MAS0,r4 1130 tlbre 1131 mfspr r4,SPRN_MAS1 1132 andis. r4,r4,MAS1_VALID@h 1133 bne 1b 1134 1135 /* Get the tlb entry used by the current running code */ 1136 bl 0f 11370: mflr r4 1138 tlbsx 0,r4 1139 1140 mfspr r4,SPRN_MAS1 1141 ori r4,r4,MAS1_TS /* Set the TS = 1 */ 1142 mtspr SPRN_MAS1,r4 1143 1144 mfspr r4,SPRN_MAS0 1145 rlwinm r4,r4,0,~MAS0_ESEL_MASK 1146 rlwimi r4,r3,16,4,15 /* Setup MAS0 = TLBSEL | ESEL(r3) */ 1147 mtspr SPRN_MAS0,r4 1148 tlbwe 1149 isync 1150 sync 1151 1152 mfmsr r4 1153 ori r4,r4,MSR_IS | MSR_DS 1154 mtspr SPRN_SRR0,r5 1155 mtspr SPRN_SRR1,r4 1156 sync 1157 rfi 1158 1159/* 1160 * Restore to the address space 0 and also invalidate the tlb entry created 1161 * by switch_to_as1. 1162 * r3 - the tlb entry which should be invalidated 1163 * r4 - __pa(PAGE_OFFSET in AS1) - __pa(PAGE_OFFSET in AS0) 1164 * r5 - device tree virtual address. If r4 is 0, r5 is ignored. 1165 * r6 - boot cpu 1166*/ 1167_GLOBAL(restore_to_as0) 1168 mflr r0 1169 1170 bl 0f 11710: mflr r9 1172 addi r9,r9,1f - 0b 1173 1174 /* 1175 * We may map the PAGE_OFFSET in AS0 to a different physical address, 1176 * so we need calculate the right jump and device tree address based 1177 * on the offset passed by r4. 1178 */ 1179 add r9,r9,r4 1180 add r5,r5,r4 1181 add r0,r0,r4 1182 11832: mfmsr r7 1184 li r8,(MSR_IS | MSR_DS) 1185 andc r7,r7,r8 1186 1187 mtspr SPRN_SRR0,r9 1188 mtspr SPRN_SRR1,r7 1189 sync 1190 rfi 1191 1192 /* Invalidate the temporary tlb entry for AS1 */ 11931: lis r9,0x1000 /* Set MAS0(TLBSEL) = 1 */ 1194 rlwimi r9,r3,16,4,15 /* Setup MAS0 = TLBSEL | ESEL(r3) */ 1195 mtspr SPRN_MAS0,r9 1196 tlbre 1197 mfspr r9,SPRN_MAS1 1198 rlwinm r9,r9,0,2,31 /* Clear MAS1 Valid and IPPROT */ 1199 mtspr SPRN_MAS1,r9 1200 tlbwe 1201 isync 1202 1203 cmpwi r4,0 1204 cmpwi cr1,r6,0 1205 cror eq,4*cr1+eq,eq 1206 bne 3f /* offset != 0 && is_boot_cpu */ 1207 mtlr r0 1208 blr 1209 1210 /* 1211 * The PAGE_OFFSET will map to a different physical address, 1212 * jump to _start to do another relocation again. 1213 */ 12143: mr r3,r5 1215 bl _start 1216 1217/* 1218 * We put a few things here that have to be page-aligned. This stuff 1219 * goes at the beginning of the data segment, which is page-aligned. 1220 */ 1221 .data 1222 .align 12 1223 .globl sdata 1224sdata: 1225 .globl empty_zero_page 1226empty_zero_page: 1227 .space 4096 1228EXPORT_SYMBOL(empty_zero_page) 1229 .globl swapper_pg_dir 1230swapper_pg_dir: 1231 .space PGD_TABLE_SIZE 1232 1233/* 1234 * Room for two PTE pointers, usually the kernel and current user pointers 1235 * to their respective root page table. 1236 */ 1237abatron_pteptrs: 1238 .space 8 1239