Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/i386/i386/locore.s
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1 /*- 2 * Copyright (c) 1990 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * William Jolitz. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * from: @(#)locore.s 7.3 (Berkeley) 5/13/91 37 * $FreeBSD: src/sys/i386/i386/locore.s,v 1.75.2.6 1999/09/05 08:11:09 peter Exp $ 38 * 39 * originally from: locore.s, by William F. Jolitz 40 * 41 * Substantially rewritten by David Greenman, Rod Grimes, 42 * Bruce Evans, Wolfgang Solfrank, Poul-Henning Kamp 43 * and many others. 44 */ 45 46 #include "apm.h" 47 #include "opt_cpu.h" 48 #include "opt_ddb.h" 49 #include "opt_userconfig.h" 50 51 #include <sys/errno.h> 52 #include <sys/syscall.h> 53 #include <sys/reboot.h> 54 55 #include <machine/asmacros.h> 56 #include <machine/cputypes.h> 57 #include <machine/psl.h> 58 #include <machine/pmap.h> 59 #include <machine/specialreg.h> 60 61 #include "assym.s" 62 63 /* 64 * XXX 65 * 66 * Note: This version greatly munged to avoid various assembler errors 67 * that may be fixed in newer versions of gas. Perhaps newer versions 68 * will have more pleasant appearance. 69 */ 70 71 /* 72 * PTmap is recursive pagemap at top of virtual address space. 73 * Within PTmap, the page directory can be found (third indirection). 74 */ 75 .globl _PTmap,_PTD,_PTDpde 76 .set _PTmap,(PTDPTDI << PDRSHIFT) 77 .set _PTD,_PTmap + (PTDPTDI * PAGE_SIZE) 78 .set _PTDpde,_PTD + (PTDPTDI * PDESIZE) 79 80 /* 81 * APTmap, APTD is the alternate recursive pagemap. 82 * It's used when modifying another process's page tables. 83 */ 84 .globl _APTmap,_APTD,_APTDpde 85 .set _APTmap,APTDPTDI << PDRSHIFT 86 .set _APTD,_APTmap + (APTDPTDI * PAGE_SIZE) 87 .set _APTDpde,_PTD + (APTDPTDI * PDESIZE) 88 89 /* 90 * Access to each processes kernel stack is via a region of 91 * per-process address space (at the beginning), immediately above 92 * the user process stack. 93 */ 94 .set _kstack,USRSTACK 95 .globl _kstack 96 97 /* 98 * Globals 99 */ 100 .data 101 ALIGN_DATA /* just to be sure */ 102 103 .globl tmpstk 104 .space 0x2000 /* space for tmpstk - temporary stack */ 105 tmpstk: 106 107 .globl _boothowto,_bootdev 108 109 .globl _cpu,_cpu_vendor,_cpu_id,_bootinfo 110 .globl _cpu_high, _cpu_feature 111 112 _cpu: .long 0 /* are we 386, 386sx, or 486 */ 113 _cpu_id: .long 0 /* stepping ID */ 114 _cpu_high: .long 0 /* highest arg to CPUID */ 115 _cpu_feature: .long 0 /* features */ 116 _cpu_vendor: .space 20 /* CPU origin code */ 117 _bootinfo: .space BOOTINFO_SIZE /* bootinfo that we can handle */ 118 119 _KERNend: .long 0 /* phys addr end of kernel (just after bss) */ 120 physfree: .long 0 /* phys addr of next free page */ 121 p0upa: .long 0 /* phys addr of proc0's UPAGES */ 122 p0upt: .long 0 /* phys addr of proc0's UPAGES page table */ 123 124 .globl _IdlePTD 125 _IdlePTD: .long 0 /* phys addr of kernel PTD */ 126 127 _KPTphys: .long 0 /* phys addr of kernel page tables */ 128 129 .globl _proc0paddr 130 _proc0paddr: .long 0 /* address of proc 0 address space */ 131 132 #ifdef BDE_DEBUGGER 133 .globl _bdb_exists /* flag to indicate BDE debugger is present */ 134 _bdb_exists: .long 0 135 #endif 136 137 138 /********************************************************************** 139 * 140 * Some handy macros 141 * 142 */ 143 144 #define R(foo) ((foo)-KERNBASE) 145 146 #define ALLOCPAGES(foo) \ 147 movl R(physfree), %esi ; \ 148 movl $((foo)*PAGE_SIZE), %eax ; \ 149 addl %esi, %eax ; \ 150 movl %eax, R(physfree) ; \ 151 movl %esi, %edi ; \ 152 movl $((foo)*PAGE_SIZE),%ecx ; \ 153 xorl %eax,%eax ; \ 154 cld ; \ 155 rep ; \ 156 stosb 157 158 /* 159 * fillkpt 160 * eax = page frame address 161 * ebx = index into page table 162 * ecx = how many pages to map 163 * base = base address of page dir/table 164 * prot = protection bits 165 */ 166 #define fillkpt(base, prot) \ 167 shll $2,%ebx ; \ 168 addl base,%ebx ; \ 169 orl $PG_V,%eax ; \ 170 orl prot,%eax ; \ 171 1: movl %eax,(%ebx) ; \ 172 addl $PAGE_SIZE,%eax ; /* increment physical address */ \ 173 addl $4,%ebx ; /* next pte */ \ 174 loop 1b 175 176 /* 177 * fillkptphys(prot) 178 * eax = physical address 179 * ecx = how many pages to map 180 * prot = protection bits 181 */ 182 #define fillkptphys(prot) \ 183 movl %eax, %ebx ; \ 184 shrl $PAGE_SHIFT, %ebx ; \ 185 fillkpt(R(_KPTphys), prot) 186 187 .text 188 /********************************************************************** 189 * 190 * This is where the bootblocks start us, set the ball rolling... 191 * 192 */ 193 NON_GPROF_ENTRY(btext) 194 195 #ifdef PC98 196 jmp 1f 197 .globl _pc98_system_parameter 198 .org 0x400 199 _pc98_system_parameter: 200 .space 0x240 /* BIOS parameter block */ 201 1: 202 /* save SYSTEM PARAMETER for resume (NS/T or other) */ 203 movl $0xa1000,%esi 204 movl $0x100000,%edi 205 movl $0x0630,%ecx 206 cld 207 rep 208 movsb 209 #else /* IBM-PC */ 210 #ifdef BDE_DEBUGGER 211 #ifdef BIOS_STEALS_3K 212 cmpl $0x0375c339,0x95504 213 #else 214 cmpl $0x0375c339,0x96104 /* XXX - debugger signature */ 215 #endif 216 jne 1f 217 movb $1,R(_bdb_exists) 218 1: 219 #endif 220 221 /* Tell the bios to warmboot next time */ 222 movw $0x1234,0x472 223 #endif /* PC98 */ 224 225 /* Set up a real frame in case the double return in newboot is executed. */ 226 pushl %ebp 227 movl %esp, %ebp 228 229 /* Don't trust what the BIOS gives for eflags. */ 230 pushl $PSL_KERNEL 231 popfl 232 233 /* 234 * Don't trust what the BIOS gives for %fs and %gs. Trust the bootstrap 235 * to set %cs, %ds, %es and %ss. 236 */ 237 mov %ds, %ax 238 mov %ax, %fs 239 mov %ax, %gs 240 241 call recover_bootinfo 242 243 /* Get onto a stack that we can trust. */ 244 /* 245 * XXX this step is delayed in case recover_bootinfo needs to return via 246 * the old stack, but it need not be, since recover_bootinfo actually 247 * returns via the old frame. 248 */ 249 movl $R(tmpstk),%esp 250 251 #ifdef PC98 252 testb $0x02,0x100620 /* pc98_machine_type & M_EPSON_PC98 */ 253 jz 3f 254 cmpb $0x0b,0x100624 /* epson_machine_id <= 0x0b */ 255 ja 3f 256 257 /* count up memory */ 258 movl $0x100000,%eax /* next, talley remaining memory */ 259 movl $0xFFF-0x100,%ecx 260 1: movl 0(%eax),%ebx /* save location to check */ 261 movl $0xa55a5aa5,0(%eax) /* write test pattern */ 262 cmpl $0xa55a5aa5,0(%eax) /* does not check yet for rollover */ 263 jne 2f 264 movl %ebx,0(%eax) /* restore memory */ 265 addl $PAGE_SIZE,%eax 266 loop 1b 267 2: subl $0x100000,%eax 268 shrl $17,%eax 269 movb %al,0x100401 270 3: 271 #endif 272 273 call identify_cpu 274 275 /* clear bss */ 276 /* 277 * XXX this should be done a little earlier. 278 * 279 * XXX we don't check that there is memory for our bss and page tables 280 * before using it. 281 * 282 * XXX the boot program somewhat bogusly clears the bss. We still have 283 * to do it in case we were unzipped by kzipboot. Then the boot program 284 * only clears kzipboot's bss. 285 * 286 * XXX the gdt and idt are still somewhere in the boot program. We 287 * depend on the convention that the boot program is below 1MB and we 288 * are above 1MB to keep the gdt and idt away from the bss and page 289 * tables. The idt is only used if BDE_DEBUGGER is enabled. 290 */ 291 movl $R(_end),%ecx 292 movl $R(_edata),%edi 293 subl %edi,%ecx 294 xorl %eax,%eax 295 cld 296 rep 297 stosb 298 299 #if NAPM > 0 300 /* 301 * XXX it's not clear that APM can live in the current environonment. 302 * Only pc-relative addressing works. 303 */ 304 call _apm_setup 305 #endif 306 307 call create_pagetables 308 309 #ifdef BDE_DEBUGGER 310 /* 311 * Adjust as much as possible for paging before enabling paging so that the 312 * adjustments can be traced. 313 */ 314 call bdb_prepare_paging 315 #endif 316 317 /* Now enable paging */ 318 movl R(_IdlePTD), %eax 319 movl %eax,%cr3 /* load ptd addr into mmu */ 320 movl %cr0,%eax /* get control word */ 321 orl $CR0_PE|CR0_PG,%eax /* enable paging */ 322 movl %eax,%cr0 /* and let's page NOW! */ 323 324 #ifdef BDE_DEBUGGER 325 /* 326 * Complete the adjustments for paging so that we can keep tracing through 327 * initi386() after the low (physical) addresses for the gdt and idt become 328 * invalid. 329 */ 330 call bdb_commit_paging 331 #endif 332 333 pushl $begin /* jump to high virtualized address */ 334 ret 335 336 /* now running relocated at KERNBASE where the system is linked to run */ 337 begin: 338 /* set up bootstrap stack */ 339 movl $_kstack+UPAGES*PAGE_SIZE,%esp /* bootstrap stack end location */ 340 xorl %eax,%eax /* mark end of frames */ 341 movl %eax,%ebp 342 movl _proc0paddr,%eax 343 movl _IdlePTD, %esi 344 movl %esi,PCB_CR3(%eax) 345 346 movl physfree, %esi 347 pushl %esi /* value of first for init386(first) */ 348 call _init386 /* wire 386 chip for unix operation */ 349 popl %esi 350 351 .globl __ucodesel,__udatasel 352 353 pushl $0 /* unused */ 354 pushl __udatasel /* ss */ 355 pushl $0 /* esp - filled in by execve() */ 356 pushl $PSL_USER /* eflags (IOPL 0, int enab) */ 357 pushl __ucodesel /* cs */ 358 pushl $0 /* eip - filled in by execve() */ 359 subl $(12*4),%esp /* space for rest of registers */ 360 361 pushl %esp /* call main with frame pointer */ 362 call _main /* autoconfiguration, mountroot etc */ 363 364 addl $(13*4),%esp /* back to a frame we can return with */ 365 366 /* 367 * Now we've run main() and determined what cpu-type we are, we can 368 * enable write protection and alignment checking on i486 cpus and 369 * above. 370 */ 371 #if defined(I486_CPU) || defined(I586_CPU) || defined(I686_CPU) 372 cmpl $CPUCLASS_386,_cpu_class 373 je 1f 374 movl %cr0,%eax /* get control word */ 375 orl $CR0_WP|CR0_AM,%eax /* enable i486 features */ 376 movl %eax,%cr0 /* and do it */ 377 1: 378 #endif 379 /* 380 * on return from main(), we are process 1 381 * set up address space and stack so that we can 'return' to user mode 382 */ 383 movl __ucodesel,%eax 384 movl __udatasel,%ecx 385 386 movl %cx,%ds 387 movl %cx,%es 388 movl %ax,%fs /* double map cs to fs */ 389 movl %cx,%gs /* and ds to gs */ 390 iret /* goto user! */ 391 392 #define LCALL(x,y) .byte 0x9a ; .long y ; .word x 393 394 /* 395 * Signal trampoline, copied to top of user stack 396 */ 397 NON_GPROF_ENTRY(sigcode) 398 call SIGF_HANDLER(%esp) 399 lea SIGF_SC(%esp),%eax /* scp (the call may have clobbered the */ 400 /* copy at 8(%esp)) */ 401 pushl %eax 402 pushl %eax /* junk to fake return address */ 403 movl $SYS_sigreturn,%eax /* sigreturn() */ 404 LCALL(0x7,0) /* enter kernel with args on stack */ 405 hlt /* never gets here */ 406 .align 2,0x90 /* long word text-align */ 407 _esigcode: 408 409 .data 410 .globl _szsigcode 411 _szsigcode: 412 .long _esigcode-_sigcode 413 .text 414 415 /********************************************************************** 416 * 417 * Recover the bootinfo passed to us from the boot program 418 * 419 */ 420 recover_bootinfo: 421 /* 422 * This code is called in different ways depending on what loaded 423 * and started the kernel. This is used to detect how we get the 424 * arguments from the other code and what we do with them. 425 * 426 * Old disk boot blocks: 427 * (*btext)(howto, bootdev, cyloffset, esym); 428 * [return address == 0, and can NOT be returned to] 429 * [cyloffset was not supported by the FreeBSD boot code 430 * and always passed in as 0] 431 * [esym is also known as total in the boot code, and 432 * was never properly supported by the FreeBSD boot code] 433 * 434 * Old diskless netboot code: 435 * (*btext)(0,0,0,0,&nfsdiskless,0,0,0); 436 * [return address != 0, and can NOT be returned to] 437 * If we are being booted by this code it will NOT work, 438 * so we are just going to halt if we find this case. 439 * 440 * New uniform boot code: 441 * (*btext)(howto, bootdev, 0, 0, 0, &bootinfo) 442 * [return address != 0, and can be returned to] 443 * 444 * There may seem to be a lot of wasted arguments in here, but 445 * that is so the newer boot code can still load very old kernels 446 * and old boot code can load new kernels. 447 */ 448 449 /* 450 * The old style disk boot blocks fake a frame on the stack and 451 * did an lret to get here. The frame on the stack has a return 452 * address of 0. 453 */ 454 cmpl $0,4(%ebp) 455 je olddiskboot 456 457 /* 458 * We have some form of return address, so this is either the 459 * old diskless netboot code, or the new uniform code. That can 460 * be detected by looking at the 5th argument, if it is 0 461 * we are being booted by the new uniform boot code. 462 */ 463 cmpl $0,24(%ebp) 464 je newboot 465 466 /* 467 * Seems we have been loaded by the old diskless boot code, we 468 * don't stand a chance of running as the diskless structure 469 * changed considerably between the two, so just halt. 470 */ 471 hlt 472 473 /* 474 * We have been loaded by the new uniform boot code. 475 * Let's check the bootinfo version, and if we do not understand 476 * it we return to the loader with a status of 1 to indicate this error 477 */ 478 newboot: 479 movl 28(%ebp),%ebx /* &bootinfo.version */ 480 movl BI_VERSION(%ebx),%eax 481 cmpl $1,%eax /* We only understand version 1 */ 482 je 1f 483 movl $1,%eax /* Return status */ 484 leave 485 /* 486 * XXX this returns to our caller's caller (as is required) since 487 * we didn't set up a frame and our caller did. 488 */ 489 ret 490 491 1: 492 /* 493 * If we have a kernelname copy it in 494 */ 495 movl BI_KERNELNAME(%ebx),%esi 496 cmpl $0,%esi 497 je 2f /* No kernelname */ 498 movl $MAXPATHLEN,%ecx /* Brute force!!! */ 499 movl $R(_kernelname),%edi 500 cmpb $'/',(%esi) /* Make sure it starts with a slash */ 501 je 1f 502 movb $'/',(%edi) 503 incl %edi 504 decl %ecx 505 1: 506 cld 507 rep 508 movsb 509 510 2: 511 /* 512 * Determine the size of the boot loader's copy of the bootinfo 513 * struct. This is impossible to do properly because old versions 514 * of the struct don't contain a size field and there are 2 old 515 * versions with the same version number. 516 */ 517 movl $BI_ENDCOMMON,%ecx /* prepare for sizeless version */ 518 testl $RB_BOOTINFO,8(%ebp) /* bi_size (and bootinfo) valid? */ 519 je got_bi_size /* no, sizeless version */ 520 movl BI_SIZE(%ebx),%ecx 521 got_bi_size: 522 523 /* 524 * Copy the common part of the bootinfo struct 525 */ 526 movl %ebx,%esi 527 movl $R(_bootinfo),%edi 528 cmpl $BOOTINFO_SIZE,%ecx 529 jbe got_common_bi_size 530 movl $BOOTINFO_SIZE,%ecx 531 got_common_bi_size: 532 cld 533 rep 534 movsb 535 536 #ifdef NFS 537 /* 538 * If we have a nfs_diskless structure copy it in 539 */ 540 movl BI_NFS_DISKLESS(%ebx),%esi 541 cmpl $0,%esi 542 je olddiskboot 543 movl $R(_nfs_diskless),%edi 544 movl $NFSDISKLESS_SIZE,%ecx 545 cld 546 rep 547 movsb 548 movl $R(_nfs_diskless_valid),%edi 549 movl $1,(%edi) 550 #endif 551 552 /* 553 * The old style disk boot. 554 * (*btext)(howto, bootdev, cyloffset, esym); 555 * Note that the newer boot code just falls into here to pick 556 * up howto and bootdev, cyloffset and esym are no longer used 557 */ 558 olddiskboot: 559 movl 8(%ebp),%eax 560 movl %eax,R(_boothowto) 561 movl 12(%ebp),%eax 562 movl %eax,R(_bootdev) 563 564 #if defined(USERCONFIG_BOOT) && defined(USERCONFIG) 565 movl $0x10200, %esi 566 movl $R(_userconfig_from_boot),%edi 567 movl $512,%ecx 568 cld 569 rep 570 movsb 571 #endif /* USERCONFIG_BOOT */ 572 573 ret 574 575 576 /********************************************************************** 577 * 578 * Identify the CPU and initialize anything special about it 579 * 580 */ 581 identify_cpu: 582 583 /* Try to toggle alignment check flag; does not exist on 386. */ 584 pushfl 585 popl %eax 586 movl %eax,%ecx 587 orl $PSL_AC,%eax 588 pushl %eax 589 popfl 590 pushfl 591 popl %eax 592 xorl %ecx,%eax 593 andl $PSL_AC,%eax 594 pushl %ecx 595 popfl 596 597 testl %eax,%eax 598 jnz try486 599 600 /* NexGen CPU does not have aligment check flag. */ 601 pushfl 602 movl $0x5555, %eax 603 xorl %edx, %edx 604 movl $2, %ecx 605 clc 606 divl %ecx 607 jz trynexgen 608 popfl 609 movl $CPU_386,R(_cpu) 610 jmp 3f 611 612 trynexgen: 613 popfl 614 movl $CPU_NX586,R(_cpu) 615 movl $0x4778654e,R(_cpu_vendor) # store vendor string 616 movl $0x72446e65,R(_cpu_vendor+4) 617 movl $0x6e657669,R(_cpu_vendor+8) 618 movl $0,R(_cpu_vendor+12) 619 jmp 3f 620 621 try486: /* Try to toggle identification flag; does not exist on early 486s. */ 622 pushfl 623 popl %eax 624 movl %eax,%ecx 625 xorl $PSL_ID,%eax 626 pushl %eax 627 popfl 628 pushfl 629 popl %eax 630 xorl %ecx,%eax 631 andl $PSL_ID,%eax 632 pushl %ecx 633 popfl 634 635 testl %eax,%eax 636 jnz trycpuid 637 movl $CPU_486,R(_cpu) 638 639 /* 640 * Check Cyrix CPU 641 * Cyrix CPUs do not change the undefined flags following 642 * execution of the divide instruction which divides 5 by 2. 643 * 644 * Note: CPUID is enabled on M2, so it passes another way. 645 */ 646 pushfl 647 movl $0x5555, %eax 648 xorl %edx, %edx 649 movl $2, %ecx 650 clc 651 divl %ecx 652 jnc trycyrix 653 popfl 654 jmp 3f /* You may use Intel CPU. */ 655 656 trycyrix: 657 popfl 658 /* 659 * IBM Bluelighting CPU also doesn't change the undefined flags. 660 * Because IBM doesn't disclose the information for Bluelighting 661 * CPU, we couldn't distinguish it from Cyrix's (including IBM 662 * brand of Cyrix CPUs). 663 */ 664 movl $0x69727943,R(_cpu_vendor) # store vendor string 665 movl $0x736e4978,R(_cpu_vendor+4) 666 movl $0x64616574,R(_cpu_vendor+8) 667 jmp 3f 668 669 trycpuid: /* Use the `cpuid' instruction. */ 670 xorl %eax,%eax 671 .byte 0x0f,0xa2 # cpuid 0 672 movl %eax,R(_cpu_high) # highest capability 673 movl %ebx,R(_cpu_vendor) # store vendor string 674 movl %edx,R(_cpu_vendor+4) 675 movl %ecx,R(_cpu_vendor+8) 676 movb $0,R(_cpu_vendor+12) 677 678 movl $1,%eax 679 .byte 0x0f,0xa2 # cpuid 1 680 movl %eax,R(_cpu_id) # store cpu_id 681 movl %edx,R(_cpu_feature) # store cpu_feature 682 rorl $8,%eax # extract family type 683 andl $15,%eax 684 cmpl $5,%eax 685 jae 1f 686 687 /* less than Pentium; must be 486 */ 688 movl $CPU_486,R(_cpu) 689 jmp 3f 690 1: 691 /* a Pentium? */ 692 cmpl $5,%eax 693 jne 2f 694 movl $CPU_586,R(_cpu) 695 jmp 3f 696 2: 697 /* Greater than Pentium...call it a Pentium Pro */ 698 movl $CPU_686,R(_cpu) 699 3: 700 ret 701 702 703 /********************************************************************** 704 * 705 * Create the first page directory and its page tables. 706 * 707 */ 708 709 create_pagetables: 710 711 testl $CPUID_PGE, R(_cpu_feature) 712 jz 1f 713 movl %cr4, %eax 714 orl $CR4_PGE, %eax 715 movl %eax, %cr4 716 1: 717 718 /* Find end of kernel image (rounded up to a page boundary). */ 719 movl $R(_end),%esi 720 721 /* include symbols in "kernel image" if they are loaded and useful */ 722 #ifdef DDB 723 movl R(_bootinfo+BI_ESYMTAB),%edi 724 testl %edi,%edi 725 je over_symalloc 726 movl %edi,%esi 727 movl $KERNBASE,%edi 728 addl %edi,R(_bootinfo+BI_SYMTAB) 729 addl %edi,R(_bootinfo+BI_ESYMTAB) 730 over_symalloc: 731 #endif 732 733 addl $PAGE_MASK,%esi 734 andl $~PAGE_MASK,%esi 735 movl %esi,R(_KERNend) /* save end of kernel */ 736 movl %esi,R(physfree) /* next free page is at end of kernel */ 737 738 /* Allocate Kernel Page Tables */ 739 ALLOCPAGES(NKPT) 740 movl %esi,R(_KPTphys) 741 742 /* Allocate Page Table Directory */ 743 ALLOCPAGES(1) 744 movl %esi,R(_IdlePTD) 745 746 /* Allocate UPAGES */ 747 ALLOCPAGES(UPAGES) 748 movl %esi,R(p0upa) 749 addl $KERNBASE, %esi 750 movl %esi, R(_proc0paddr) 751 752 /* Allocate proc0's page table for the UPAGES. */ 753 ALLOCPAGES(1) 754 movl %esi,R(p0upt) 755 756 /* Map read-only from zero to the end of the kernel text section */ 757 xorl %eax, %eax 758 #ifdef BDE_DEBUGGER 759 /* If the debugger is present, actually map everything read-write. */ 760 cmpl $0,R(_bdb_exists) 761 jne map_read_write 762 #endif 763 xorl %edx,%edx 764 testl $CPUID_PGE, R(_cpu_feature) 765 jz 2f 766 orl $PG_G,%edx 767 768 2: movl $R(_etext),%ecx 769 addl $PAGE_MASK,%ecx 770 shrl $PAGE_SHIFT,%ecx 771 fillkptphys(%edx) 772 773 /* Map read-write, data, bss and symbols */ 774 movl $R(_etext),%eax 775 addl $PAGE_MASK, %eax 776 andl $~PAGE_MASK, %eax 777 map_read_write: 778 movl $PG_RW,%edx 779 testl $CPUID_PGE, R(_cpu_feature) 780 jz 1f 781 orl $PG_G,%edx 782 783 1: movl R(_KERNend),%ecx 784 subl %eax,%ecx 785 shrl $PAGE_SHIFT,%ecx 786 fillkptphys(%edx) 787 788 /* Map page directory. */ 789 movl R(_IdlePTD), %eax 790 movl $1, %ecx 791 fillkptphys($PG_RW) 792 793 /* Map proc0's page table for the UPAGES. */ 794 movl R(p0upt), %eax 795 movl $1, %ecx 796 fillkptphys($PG_RW) 797 798 /* Map proc0's UPAGES in the physical way ... */ 799 movl R(p0upa), %eax 800 movl $UPAGES, %ecx 801 fillkptphys($PG_RW) 802 803 /* Map ISA hole */ 804 movl $ISA_HOLE_START, %eax 805 movl $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx 806 fillkptphys($PG_RW) 807 808 /* Map proc0s UPAGES in the special page table for this purpose ... */ 809 movl R(p0upa), %eax 810 movl $KSTKPTEOFF, %ebx 811 movl $UPAGES, %ecx 812 fillkpt(R(p0upt), $PG_RW) 813 814 /* ... and put the page table in the pde. */ 815 movl R(p0upt), %eax 816 movl $KSTKPTDI, %ebx 817 movl $1, %ecx 818 fillkpt(R(_IdlePTD), $PG_RW) 819 820 /* install a pde for temporary double map of bottom of VA */ 821 movl R(_KPTphys), %eax 822 xorl %ebx, %ebx 823 movl $1, %ecx 824 fillkpt(R(_IdlePTD), $PG_RW) 825 826 /* install pde's for pt's */ 827 movl R(_KPTphys), %eax 828 movl $KPTDI, %ebx 829 movl $NKPT, %ecx 830 fillkpt(R(_IdlePTD), $PG_RW) 831 832 /* install a pde recursively mapping page directory as a page table */ 833 movl R(_IdlePTD), %eax 834 movl $PTDPTDI, %ebx 835 movl $1,%ecx 836 fillkpt(R(_IdlePTD), $PG_RW) 837 838 ret 839 840 #ifdef BDE_DEBUGGER 841 bdb_prepare_paging: 842 cmpl $0,R(_bdb_exists) 843 je bdb_prepare_paging_exit 844 845 subl $6,%esp 846 847 /* 848 * Copy and convert debugger entries from the bootstrap gdt and idt 849 * to the kernel gdt and idt. Everything is still in low memory. 850 * Tracing continues to work after paging is enabled because the 851 * low memory addresses remain valid until everything is relocated. 852 * However, tracing through the setidt() that initializes the trace 853 * trap will crash. 854 */ 855 sgdt (%esp) 856 movl 2(%esp),%esi /* base address of bootstrap gdt */ 857 movl $R(_gdt),%edi 858 movl %edi,2(%esp) /* prepare to load kernel gdt */ 859 movl $8*18/4,%ecx 860 cld 861 rep /* copy gdt */ 862 movsl 863 movl $R(_gdt),-8+2(%edi) /* adjust gdt self-ptr */ 864 movb $0x92,-8+5(%edi) 865 lgdt (%esp) 866 867 sidt (%esp) 868 movl 2(%esp),%esi /* base address of current idt */ 869 movl 8+4(%esi),%eax /* convert dbg descriptor to ... */ 870 movw 8(%esi),%ax 871 movl %eax,R(bdb_dbg_ljmp+1) /* ... immediate offset ... */ 872 movl 8+2(%esi),%eax 873 movw %ax,R(bdb_dbg_ljmp+5) /* ... and selector for ljmp */ 874 movl 24+4(%esi),%eax /* same for bpt descriptor */ 875 movw 24(%esi),%ax 876 movl %eax,R(bdb_bpt_ljmp+1) 877 movl 24+2(%esi),%eax 878 movw %ax,R(bdb_bpt_ljmp+5) 879 movl $R(_idt),%edi 880 movl %edi,2(%esp) /* prepare to load kernel idt */ 881 movl $8*4/4,%ecx 882 cld 883 rep /* copy idt */ 884 movsl 885 lidt (%esp) 886 887 addl $6,%esp 888 889 bdb_prepare_paging_exit: 890 ret 891 892 /* Relocate debugger gdt entries and gdt and idt pointers. */ 893 bdb_commit_paging: 894 cmpl $0,_bdb_exists 895 je bdb_commit_paging_exit 896 897 movl $_gdt+8*9,%eax /* adjust slots 9-17 */ 898 movl $9,%ecx 899 reloc_gdt: 900 movb $KERNBASE>>24,7(%eax) /* top byte of base addresses, was 0, */ 901 addl $8,%eax /* now KERNBASE>>24 */ 902 loop reloc_gdt 903 904 subl $6,%esp 905 sgdt (%esp) 906 addl $KERNBASE,2(%esp) 907 lgdt (%esp) 908 sidt (%esp) 909 addl $KERNBASE,2(%esp) 910 lidt (%esp) 911 addl $6,%esp 912 913 int $3 914 915 bdb_commit_paging_exit: 916 ret 917 918 #endif /* BDE_DEBUGGER */
Cache object: 0d42533c07406db9b89e20dfef5decd7
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