sys/i386/i386/locore.s

   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  * 4. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  *      from: @(#)locore.s      7.3 (Berkeley) 5/13/91
  33  * $FreeBSD$
  34  *
  35  *              originally from: locore.s, by William F. Jolitz
  36  *
  37  *              Substantially rewritten by David Greenman, Rod Grimes,
  38  *                      Bruce Evans, Wolfgang Solfrank, Poul-Henning Kamp
  39  *                      and many others.
  40  */
  41
  42 #include "opt_bootp.h"
  43 #include "opt_compat.h"
  44 #include "opt_nfsroot.h"
  45 #include "opt_pmap.h"
  46
  47 #include <sys/syscall.h>
  48 #include <sys/reboot.h>
  49
  50 #include <machine/asmacros.h>
  51 #include <machine/cputypes.h>
  52 #include <machine/psl.h>
  53 #include <machine/pmap.h>
  54 #include <machine/specialreg.h>
  55
  56 #include "assym.s"
  57
  58 /*
  59  *      XXX
  60  *
  61  * Note: This version greatly munged to avoid various assembler errors
  62  * that may be fixed in newer versions of gas. Perhaps newer versions
  63  * will have more pleasant appearance.
  64  */
  65
  66 /*
  67  * PTmap is recursive pagemap at top of virtual address space.
  68  * Within PTmap, the page directory can be found (third indirection).
  69  */
  70         .globl  PTmap,PTD,PTDpde
  71         .set    PTmap,(PTDPTDI << PDRSHIFT)
  72         .set    PTD,PTmap + (PTDPTDI * PAGE_SIZE)
  73         .set    PTDpde,PTD + (PTDPTDI * PDESIZE)
  74
  75 /*
  76  * Compiled KERNBASE location and the kernel load address
  77  */
  78         .globl  kernbase
  79         .set    kernbase,KERNBASE
  80         .globl  kernload
  81         .set    kernload,KERNLOAD
  82
  83 /*
  84  * Globals
  85  */
  86         .data
  87         ALIGN_DATA                      /* just to be sure */
  88
  89         .space  0x2000                  /* space for tmpstk - temporary stack */
  90 tmpstk:
  91
  92         .globl  bootinfo
  93 bootinfo:       .space  BOOTINFO_SIZE   /* bootinfo that we can handle */
  94
  95                 .globl KERNend
  96 KERNend:        .long   0               /* phys addr end of kernel (just after bss) */
  97 physfree:       .long   0               /* phys addr of next free page */
  98
  99         .globl  IdlePTD
 100 IdlePTD:        .long   0               /* phys addr of kernel PTD */
 101
 102 #if defined(PAE) || defined(PAE_TABLES)
 103         .globl  IdlePDPT
 104 IdlePDPT:       .long   0               /* phys addr of kernel PDPT */
 105 #endif
 106
 107         .globl  KPTmap
 108 KPTmap:         .long   0               /* address of kernel page tables */
 109
 110         .globl  KPTphys
 111 KPTphys:        .long   0               /* phys addr of kernel page tables */
 112
 113         .globl  proc0kstack
 114 proc0kstack:    .long   0               /* address of proc 0 kstack space */
 115 p0kpa:          .long   0               /* phys addr of proc0's STACK */
 116
 117 vm86phystk:     .long   0               /* PA of vm86/bios stack */
 118
 119         .globl  vm86paddr, vm86pa
 120 vm86paddr:      .long   0               /* address of vm86 region */
 121 vm86pa:         .long   0               /* phys addr of vm86 region */
 122
 123 #ifdef PC98
 124         .globl  pc98_system_parameter
 125 pc98_system_parameter:
 126         .space  0x240
 127 #endif
 128
 129 /**********************************************************************
 130  *
 131  * Some handy macros
 132  *
 133  */
 134
 135 #define R(foo) ((foo)-KERNBASE)
 136
 137 #define ALLOCPAGES(foo) \
 138         movl    R(physfree), %esi ; \
 139         movl    $((foo)*PAGE_SIZE), %eax ; \
 140         addl    %esi, %eax ; \
 141         movl    %eax, R(physfree) ; \
 142         movl    %esi, %edi ; \
 143         movl    $((foo)*PAGE_SIZE),%ecx ; \
 144         xorl    %eax,%eax ; \
 145         cld ; \
 146         rep ; \
 147         stosb
 148
 149 /*
 150  * fillkpt
 151  *      eax = page frame address
 152  *      ebx = index into page table
 153  *      ecx = how many pages to map
 154  *      base = base address of page dir/table
 155  *      prot = protection bits
 156  */
 157 #define fillkpt(base, prot)               \
 158         shll    $PTESHIFT,%ebx          ; \
 159         addl    base,%ebx               ; \
 160         orl     $PG_V,%eax              ; \
 161         orl     prot,%eax               ; \
 162 1:      movl    %eax,(%ebx)             ; \
 163         addl    $PAGE_SIZE,%eax         ; /* increment physical address */ \
 164         addl    $PTESIZE,%ebx           ; /* next pte */ \
 165         loop    1b
 166
 167 /*
 168  * fillkptphys(prot)
 169  *      eax = physical address
 170  *      ecx = how many pages to map
 171  *      prot = protection bits
 172  */
 173 #define fillkptphys(prot)                 \
 174         movl    %eax, %ebx              ; \
 175         shrl    $PAGE_SHIFT, %ebx       ; \
 176         fillkpt(R(KPTphys), prot)
 177
 178         .text
 179 /**********************************************************************
 180  *
 181  * This is where the bootblocks start us, set the ball rolling...
 182  *
 183  */
 184 NON_GPROF_ENTRY(btext)
 185
 186 #ifdef PC98
 187         /* save SYSTEM PARAMETER for resume (NS/T or other) */
 188         movl    $0xa1400,%esi
 189         movl    $R(pc98_system_parameter),%edi
 190         movl    $0x0240,%ecx
 191         cld
 192         rep
 193         movsb
 194 #else   /* IBM-PC */
 195 /* Tell the bios to warmboot next time */
 196         movw    $0x1234,0x472
 197 #endif  /* PC98 */
 198
 199 /* Set up a real frame in case the double return in newboot is executed. */
 200         pushl   %ebp
 201         movl    %esp, %ebp
 202
 203 /* Don't trust what the BIOS gives for eflags. */
 204         pushl   $PSL_KERNEL
 205         popfl
 206
 207 /*
 208  * Don't trust what the BIOS gives for %fs and %gs.  Trust the bootstrap
 209  * to set %cs, %ds, %es and %ss.
 210  */
 211         mov     %ds, %ax
 212         mov     %ax, %fs
 213         mov     %ax, %gs
 214
 215 /*
 216  * Clear the bss.  Not all boot programs do it, and it is our job anyway.
 217  *
 218  * XXX we don't check that there is memory for our bss and page tables
 219  * before using it.
 220  *
 221  * Note: we must be careful to not overwrite an active gdt or idt.  They
 222  * inactive from now until we switch to new ones, since we don't load any
 223  * more segment registers or permit interrupts until after the switch.
 224  */
 225         movl    $R(end),%ecx
 226         movl    $R(edata),%edi
 227         subl    %edi,%ecx
 228         xorl    %eax,%eax
 229         cld
 230         rep
 231         stosb
 232
 233         call    recover_bootinfo
 234
 235 /* Get onto a stack that we can trust. */
 236 /*
 237  * XXX this step is delayed in case recover_bootinfo needs to return via
 238  * the old stack, but it need not be, since recover_bootinfo actually
 239  * returns via the old frame.
 240  */
 241         movl    $R(tmpstk),%esp
 242
 243 #ifdef PC98
 244         /* pc98_machine_type & M_EPSON_PC98 */
 245         testb   $0x02,R(pc98_system_parameter)+220
 246         jz      3f
 247         /* epson_machine_id <= 0x0b */
 248         cmpb    $0x0b,R(pc98_system_parameter)+224
 249         ja      3f
 250
 251         /* count up memory */
 252         movl    $0x100000,%eax          /* next, talley remaining memory */
 253         movl    $0xFFF-0x100,%ecx
 254 1:      movl    0(%eax),%ebx            /* save location to check */
 255         movl    $0xa55a5aa5,0(%eax)     /* write test pattern */
 256         cmpl    $0xa55a5aa5,0(%eax)     /* does not check yet for rollover */
 257         jne     2f
 258         movl    %ebx,0(%eax)            /* restore memory */
 259         addl    $PAGE_SIZE,%eax
 260         loop    1b
 261 2:      subl    $0x100000,%eax
 262         shrl    $17,%eax
 263         movb    %al,R(pc98_system_parameter)+1
 264 3:
 265
 266         movw    R(pc98_system_parameter+0x86),%ax
 267         movw    %ax,R(cpu_id)
 268 #endif
 269
 270         call    identify_cpu
 271         call    create_pagetables
 272
 273 /*
 274  * If the CPU has support for VME, turn it on.
 275  */
 276         testl   $CPUID_VME, R(cpu_feature)
 277         jz      1f
 278         movl    %cr4, %eax
 279         orl     $CR4_VME, %eax
 280         movl    %eax, %cr4
 281 1:
 282
 283 /* Now enable paging */
 284 #if defined(PAE) || defined(PAE_TABLES)
 285         movl    R(IdlePDPT), %eax
 286         movl    %eax, %cr3
 287         movl    %cr4, %eax
 288         orl     $CR4_PAE, %eax
 289         movl    %eax, %cr4
 290 #else
 291         movl    R(IdlePTD), %eax
 292         movl    %eax,%cr3               /* load ptd addr into mmu */
 293 #endif
 294         movl    %cr0,%eax               /* get control word */
 295         orl     $CR0_PE|CR0_PG,%eax     /* enable paging */
 296         movl    %eax,%cr0               /* and let's page NOW! */
 297
 298         pushl   $begin                  /* jump to high virtualized address */
 299         ret
 300
 301 /* now running relocated at KERNBASE where the system is linked to run */
 302 begin:
 303         /* set up bootstrap stack */
 304         movl    proc0kstack,%eax        /* location of in-kernel stack */
 305
 306         /*
 307          * Only use bottom page for init386().  init386() calculates the
 308          * PCB + FPU save area size and returns the true top of stack.
 309          */
 310         leal    PAGE_SIZE(%eax),%esp
 311
 312         xorl    %ebp,%ebp               /* mark end of frames */
 313
 314         pushl   physfree                /* value of first for init386(first) */
 315         call    init386                 /* wire 386 chip for unix operation */
 316
 317         /*
 318          * Clean up the stack in a way that db_numargs() understands, so
 319          * that backtraces in ddb don't underrun the stack.  Traps for
 320          * inaccessible memory are more fatal than usual this early.
 321          */
 322         addl    $4,%esp
 323
 324         /* Switch to true top of stack. */
 325         movl    %eax,%esp
 326
 327         call    mi_startup              /* autoconfiguration, mountroot etc */
 328         /* NOTREACHED */
 329         addl    $0,%esp                 /* for db_numargs() again */
 330
 331 /*
 332  * Signal trampoline, copied to top of user stack
 333  */
 334 NON_GPROF_ENTRY(sigcode)
 335         calll   *SIGF_HANDLER(%esp)
 336         leal    SIGF_UC(%esp),%eax      /* get ucontext */
 337         pushl   %eax
 338         testl   $PSL_VM,UC_EFLAGS(%eax)
 339         jne     1f
 340         mov     UC_GS(%eax),%gs         /* restore %gs */
 341 1:
 342         movl    $SYS_sigreturn,%eax
 343         pushl   %eax                    /* junk to fake return addr. */
 344         int     $0x80                   /* enter kernel with args */
 345                                         /* on stack */
 346 1:
 347         jmp     1b
 348
 349 #ifdef COMPAT_FREEBSD4
 350         ALIGN_TEXT
 351 freebsd4_sigcode:
 352         calll   *SIGF_HANDLER(%esp)
 353         leal    SIGF_UC4(%esp),%eax     /* get ucontext */
 354         pushl   %eax
 355         testl   $PSL_VM,UC4_EFLAGS(%eax)
 356         jne     1f
 357         mov     UC4_GS(%eax),%gs        /* restore %gs */
 358 1:
 359         movl    $344,%eax               /* 4.x SYS_sigreturn */
 360         pushl   %eax                    /* junk to fake return addr. */
 361         int     $0x80                   /* enter kernel with args */
 362                                         /* on stack */
 363 1:
 364         jmp     1b
 365 #endif
 366
 367 #ifdef COMPAT_43
 368         ALIGN_TEXT
 369 osigcode:
 370         call    *SIGF_HANDLER(%esp)     /* call signal handler */
 371         lea     SIGF_SC(%esp),%eax      /* get sigcontext */
 372         pushl   %eax
 373         testl   $PSL_VM,SC_PS(%eax)
 374         jne     9f
 375         mov     SC_GS(%eax),%gs         /* restore %gs */
 376 9:
 377         movl    $103,%eax               /* 3.x SYS_sigreturn */
 378         pushl   %eax                    /* junk to fake return addr. */
 379         int     $0x80                   /* enter kernel with args */
 380 0:      jmp     0b
 381 #endif /* COMPAT_43 */
 382
 383         ALIGN_TEXT
 384 esigcode:
 385
 386         .data
 387         .globl  szsigcode
 388 szsigcode:
 389         .long   esigcode-sigcode
 390 #ifdef COMPAT_FREEBSD4
 391         .globl  szfreebsd4_sigcode
 392 szfreebsd4_sigcode:
 393         .long   esigcode-freebsd4_sigcode
 394 #endif
 395 #ifdef COMPAT_43
 396         .globl  szosigcode
 397 szosigcode:
 398         .long   esigcode-osigcode
 399 #endif
 400         .text
 401
 402 /**********************************************************************
 403  *
 404  * Recover the bootinfo passed to us from the boot program
 405  *
 406  */
 407 recover_bootinfo:
 408         /*
 409          * This code is called in different ways depending on what loaded
 410          * and started the kernel.  This is used to detect how we get the
 411          * arguments from the other code and what we do with them.
 412          *
 413          * Old disk boot blocks:
 414          *      (*btext)(howto, bootdev, cyloffset, esym);
 415          *      [return address == 0, and can NOT be returned to]
 416          *      [cyloffset was not supported by the FreeBSD boot code
 417          *       and always passed in as 0]
 418          *      [esym is also known as total in the boot code, and
 419          *       was never properly supported by the FreeBSD boot code]
 420          *
 421          * Old diskless netboot code:
 422          *      (*btext)(0,0,0,0,&nfsdiskless,0,0,0);
 423          *      [return address != 0, and can NOT be returned to]
 424          *      If we are being booted by this code it will NOT work,
 425          *      so we are just going to halt if we find this case.
 426          *
 427          * New uniform boot code:
 428          *      (*btext)(howto, bootdev, 0, 0, 0, &bootinfo)
 429          *      [return address != 0, and can be returned to]
 430          *
 431          * There may seem to be a lot of wasted arguments in here, but
 432          * that is so the newer boot code can still load very old kernels
 433          * and old boot code can load new kernels.
 434          */
 435
 436         /*
 437          * The old style disk boot blocks fake a frame on the stack and
 438          * did an lret to get here.  The frame on the stack has a return
 439          * address of 0.
 440          */
 441         cmpl    $0,4(%ebp)
 442         je      olddiskboot
 443
 444         /*
 445          * We have some form of return address, so this is either the
 446          * old diskless netboot code, or the new uniform code.  That can
 447          * be detected by looking at the 5th argument, if it is 0
 448          * we are being booted by the new uniform boot code.
 449          */
 450         cmpl    $0,24(%ebp)
 451         je      newboot
 452
 453         /*
 454          * Seems we have been loaded by the old diskless boot code, we
 455          * don't stand a chance of running as the diskless structure
 456          * changed considerably between the two, so just halt.
 457          */
 458          hlt
 459
 460         /*
 461          * We have been loaded by the new uniform boot code.
 462          * Let's check the bootinfo version, and if we do not understand
 463          * it we return to the loader with a status of 1 to indicate this error
 464          */
 465 newboot:
 466         movl    28(%ebp),%ebx           /* &bootinfo.version */
 467         movl    BI_VERSION(%ebx),%eax
 468         cmpl    $1,%eax                 /* We only understand version 1 */
 469         je      1f
 470         movl    $1,%eax                 /* Return status */
 471         leave
 472         /*
 473          * XXX this returns to our caller's caller (as is required) since
 474          * we didn't set up a frame and our caller did.
 475          */
 476         ret
 477
 478 1:
 479         /*
 480          * If we have a kernelname copy it in
 481          */
 482         movl    BI_KERNELNAME(%ebx),%esi
 483         cmpl    $0,%esi
 484         je      2f                      /* No kernelname */
 485         movl    $MAXPATHLEN,%ecx        /* Brute force!!! */
 486         movl    $R(kernelname),%edi
 487         cmpb    $'/',(%esi)             /* Make sure it starts with a slash */
 488         je      1f
 489         movb    $'/',(%edi)
 490         incl    %edi
 491         decl    %ecx
 492 1:
 493         cld
 494         rep
 495         movsb
 496
 497 2:
 498         /*
 499          * Determine the size of the boot loader's copy of the bootinfo
 500          * struct.  This is impossible to do properly because old versions
 501          * of the struct don't contain a size field and there are 2 old
 502          * versions with the same version number.
 503          */
 504         movl    $BI_ENDCOMMON,%ecx      /* prepare for sizeless version */
 505         testl   $RB_BOOTINFO,8(%ebp)    /* bi_size (and bootinfo) valid? */
 506         je      got_bi_size             /* no, sizeless version */
 507         movl    BI_SIZE(%ebx),%ecx
 508 got_bi_size:
 509
 510         /*
 511          * Copy the common part of the bootinfo struct
 512          */
 513         movl    %ebx,%esi
 514         movl    $R(bootinfo),%edi
 515         cmpl    $BOOTINFO_SIZE,%ecx
 516         jbe     got_common_bi_size
 517         movl    $BOOTINFO_SIZE,%ecx
 518 got_common_bi_size:
 519         cld
 520         rep
 521         movsb
 522
 523 #ifdef NFS_ROOT
 524 #ifndef BOOTP_NFSV3
 525         /*
 526          * If we have a nfs_diskless structure copy it in
 527          */
 528         movl    BI_NFS_DISKLESS(%ebx),%esi
 529         cmpl    $0,%esi
 530         je      olddiskboot
 531         movl    $R(nfs_diskless),%edi
 532         movl    $NFSDISKLESS_SIZE,%ecx
 533         cld
 534         rep
 535         movsb
 536         movl    $R(nfs_diskless_valid),%edi
 537         movl    $1,(%edi)
 538 #endif
 539 #endif
 540
 541         /*
 542          * The old style disk boot.
 543          *      (*btext)(howto, bootdev, cyloffset, esym);
 544          * Note that the newer boot code just falls into here to pick
 545          * up howto and bootdev, cyloffset and esym are no longer used
 546          */
 547 olddiskboot:
 548         movl    8(%ebp),%eax
 549         movl    %eax,R(boothowto)
 550         movl    12(%ebp),%eax
 551         movl    %eax,R(bootdev)
 552
 553         ret
 554
 555
 556 /**********************************************************************
 557  *
 558  * Identify the CPU and initialize anything special about it
 559  *
 560  */
 561 identify_cpu:
 562
 563         /* Try to toggle alignment check flag; does not exist on 386. */
 564         pushfl
 565         popl    %eax
 566         movl    %eax,%ecx
 567         orl     $PSL_AC,%eax
 568         pushl   %eax
 569         popfl
 570         pushfl
 571         popl    %eax
 572         xorl    %ecx,%eax
 573         andl    $PSL_AC,%eax
 574         pushl   %ecx
 575         popfl
 576
 577         testl   %eax,%eax
 578         jnz     try486
 579
 580         /* NexGen CPU does not have aligment check flag. */
 581         pushfl
 582         movl    $0x5555, %eax
 583         xorl    %edx, %edx
 584         movl    $2, %ecx
 585         clc
 586         divl    %ecx
 587         jz      trynexgen
 588         popfl
 589         movl    $CPU_386,R(cpu)
 590         jmp     3f
 591
 592 trynexgen:
 593         popfl
 594         movl    $CPU_NX586,R(cpu)
 595         movl    $0x4778654e,R(cpu_vendor)       # store vendor string
 596         movl    $0x72446e65,R(cpu_vendor+4)
 597         movl    $0x6e657669,R(cpu_vendor+8)
 598         movl    $0,R(cpu_vendor+12)
 599         jmp     3f
 600
 601 try486: /* Try to toggle identification flag; does not exist on early 486s. */
 602         pushfl
 603         popl    %eax
 604         movl    %eax,%ecx
 605         xorl    $PSL_ID,%eax
 606         pushl   %eax
 607         popfl
 608         pushfl
 609         popl    %eax
 610         xorl    %ecx,%eax
 611         andl    $PSL_ID,%eax
 612         pushl   %ecx
 613         popfl
 614
 615         testl   %eax,%eax
 616         jnz     trycpuid
 617         movl    $CPU_486,R(cpu)
 618
 619         /*
 620          * Check Cyrix CPU
 621          * Cyrix CPUs do not change the undefined flags following
 622          * execution of the divide instruction which divides 5 by 2.
 623          *
 624          * Note: CPUID is enabled on M2, so it passes another way.
 625          */
 626         pushfl
 627         movl    $0x5555, %eax
 628         xorl    %edx, %edx
 629         movl    $2, %ecx
 630         clc
 631         divl    %ecx
 632         jnc     trycyrix
 633         popfl
 634         jmp     3f              /* You may use Intel CPU. */
 635
 636 trycyrix:
 637         popfl
 638         /*
 639          * IBM Bluelighting CPU also doesn't change the undefined flags.
 640          * Because IBM doesn't disclose the information for Bluelighting
 641          * CPU, we couldn't distinguish it from Cyrix's (including IBM
 642          * brand of Cyrix CPUs).
 643          */
 644         movl    $0x69727943,R(cpu_vendor)       # store vendor string
 645         movl    $0x736e4978,R(cpu_vendor+4)
 646         movl    $0x64616574,R(cpu_vendor+8)
 647         jmp     3f
 648
 649 trycpuid:       /* Use the `cpuid' instruction. */
 650         xorl    %eax,%eax
 651         cpuid                                   # cpuid 0
 652         movl    %eax,R(cpu_high)                # highest capability
 653         movl    %ebx,R(cpu_vendor)              # store vendor string
 654         movl    %edx,R(cpu_vendor+4)
 655         movl    %ecx,R(cpu_vendor+8)
 656         movb    $0,R(cpu_vendor+12)
 657
 658         movl    $1,%eax
 659         cpuid                                   # cpuid 1
 660         movl    %eax,R(cpu_id)                  # store cpu_id
 661         movl    %ebx,R(cpu_procinfo)            # store cpu_procinfo
 662         movl    %edx,R(cpu_feature)             # store cpu_feature
 663         movl    %ecx,R(cpu_feature2)            # store cpu_feature2
 664         rorl    $8,%eax                         # extract family type
 665         andl    $15,%eax
 666         cmpl    $5,%eax
 667         jae     1f
 668
 669         /* less than Pentium; must be 486 */
 670         movl    $CPU_486,R(cpu)
 671         jmp     3f
 672 1:
 673         /* a Pentium? */
 674         cmpl    $5,%eax
 675         jne     2f
 676         movl    $CPU_586,R(cpu)
 677         jmp     3f
 678 2:
 679         /* Greater than Pentium...call it a Pentium Pro */
 680         movl    $CPU_686,R(cpu)
 681 3:
 682         ret
 683
 684
 685 /**********************************************************************
 686  *
 687  * Create the first page directory and its page tables.
 688  *
 689  */
 690
 691 create_pagetables:
 692
 693 /* Find end of kernel image (rounded up to a page boundary). */
 694         movl    $R(_end),%esi
 695
 696 /* Include symbols, if any. */
 697         movl    R(bootinfo+BI_ESYMTAB),%edi
 698         testl   %edi,%edi
 699         je      over_symalloc
 700         movl    %edi,%esi
 701         movl    $KERNBASE,%edi
 702         addl    %edi,R(bootinfo+BI_SYMTAB)
 703         addl    %edi,R(bootinfo+BI_ESYMTAB)
 704 over_symalloc:
 705
 706 /* If we are told where the end of the kernel space is, believe it. */
 707         movl    R(bootinfo+BI_KERNEND),%edi
 708         testl   %edi,%edi
 709         je      no_kernend
 710         movl    %edi,%esi
 711 no_kernend:
 712
 713         addl    $PDRMASK,%esi           /* Play conservative for now, and */
 714         andl    $~PDRMASK,%esi          /*   ... wrap to next 4M. */
 715         movl    %esi,R(KERNend)         /* save end of kernel */
 716         movl    %esi,R(physfree)        /* next free page is at end of kernel */
 717
 718 /* Allocate Kernel Page Tables */
 719         ALLOCPAGES(NKPT)
 720         movl    %esi,R(KPTphys)
 721         addl    $(KERNBASE-(KPTDI<<(PDRSHIFT-PAGE_SHIFT+PTESHIFT))),%esi
 722         movl    %esi,R(KPTmap)
 723
 724 /* Allocate Page Table Directory */
 725 #if defined(PAE) || defined(PAE_TABLES)
 726         /* XXX only need 32 bytes (easier for now) */
 727         ALLOCPAGES(1)
 728         movl    %esi,R(IdlePDPT)
 729 #endif
 730         ALLOCPAGES(NPGPTD)
 731         movl    %esi,R(IdlePTD)
 732
 733 /* Allocate KSTACK */
 734         ALLOCPAGES(TD0_KSTACK_PAGES)
 735         movl    %esi,R(p0kpa)
 736         addl    $KERNBASE, %esi
 737         movl    %esi, R(proc0kstack)
 738
 739         ALLOCPAGES(1)                   /* vm86/bios stack */
 740         movl    %esi,R(vm86phystk)
 741
 742         ALLOCPAGES(3)                   /* pgtable + ext + IOPAGES */
 743         movl    %esi,R(vm86pa)
 744         addl    $KERNBASE, %esi
 745         movl    %esi, R(vm86paddr)
 746
 747 /*
 748  * Enable PSE and PGE.
 749  */
 750 #ifndef DISABLE_PSE
 751         testl   $CPUID_PSE, R(cpu_feature)
 752         jz      1f
 753         movl    $PG_PS, R(pseflag)
 754         movl    %cr4, %eax
 755         orl     $CR4_PSE, %eax
 756         movl    %eax, %cr4
 757 1:
 758 #endif
 759 #ifndef DISABLE_PG_G
 760         testl   $CPUID_PGE, R(cpu_feature)
 761         jz      2f
 762         movl    $PG_G, R(pgeflag)
 763         movl    %cr4, %eax
 764         orl     $CR4_PGE, %eax
 765         movl    %eax, %cr4
 766 2:
 767 #endif
 768
 769 /*
 770  * Initialize page table pages mapping physical address zero through the
 771  * end of the kernel.  All of the page table entries allow read and write
 772  * access.  Write access to the first physical page is required by bios32
 773  * calls, and write access to the first 1 MB of physical memory is required
 774  * by ACPI for implementing suspend and resume.  We do this even
 775  * if we've enabled PSE above, we'll just switch the corresponding kernel
 776  * PDEs before we turn on paging.
 777  *
 778  * XXX: We waste some pages here in the PSE case!
 779  */
 780         xorl    %eax, %eax
 781         movl    R(KERNend),%ecx
 782         shrl    $PAGE_SHIFT,%ecx
 783         fillkptphys($PG_RW)
 784
 785 /* Map page table pages. */
 786         movl    R(KPTphys),%eax
 787         movl    $NKPT,%ecx
 788         fillkptphys($PG_RW)
 789
 790 /* Map page directory. */
 791 #if defined(PAE) || defined(PAE_TABLES)
 792         movl    R(IdlePDPT), %eax
 793         movl    $1, %ecx
 794         fillkptphys($PG_RW)
 795 #endif
 796
 797         movl    R(IdlePTD), %eax
 798         movl    $NPGPTD, %ecx
 799         fillkptphys($PG_RW)
 800
 801 /* Map proc0's KSTACK in the physical way ... */
 802         movl    R(p0kpa), %eax
 803         movl    $(TD0_KSTACK_PAGES), %ecx
 804         fillkptphys($PG_RW)
 805
 806 /* Map ISA hole */
 807         movl    $ISA_HOLE_START, %eax
 808         movl    $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
 809         fillkptphys($PG_RW)
 810
 811 /* Map space for the vm86 region */
 812         movl    R(vm86phystk), %eax
 813         movl    $4, %ecx
 814         fillkptphys($PG_RW)
 815
 816 /* Map page 0 into the vm86 page table */
 817         movl    $0, %eax
 818         movl    $0, %ebx
 819         movl    $1, %ecx
 820         fillkpt(R(vm86pa), $PG_RW|PG_U)
 821
 822 /* ...likewise for the ISA hole */
 823         movl    $ISA_HOLE_START, %eax
 824         movl    $ISA_HOLE_START>>PAGE_SHIFT, %ebx
 825         movl    $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
 826         fillkpt(R(vm86pa), $PG_RW|PG_U)
 827
 828 /*
 829  * Create an identity mapping for low physical memory, including the kernel.
 830  * The part of this mapping that covers the first 1 MB of physical memory
 831  * becomes a permanent part of the kernel's address space.  The rest of this
 832  * mapping is destroyed in pmap_bootstrap().  Ordinarily, the same page table
 833  * pages are shared by the identity mapping and the kernel's native mapping.
 834  * However, the permanent identity mapping cannot contain PG_G mappings.
 835  * Thus, if the kernel is loaded within the permanent identity mapping, that
 836  * page table page must be duplicated and not shared.
 837  *
 838  * N.B. Due to errata concerning large pages and physical address zero,
 839  * a PG_PS mapping is not used.
 840  */
 841         movl    R(KPTphys), %eax
 842         xorl    %ebx, %ebx
 843         movl    $NKPT, %ecx
 844         fillkpt(R(IdlePTD), $PG_RW)
 845 #if KERNLOAD < (1 << PDRSHIFT)
 846         testl   $PG_G, R(pgeflag)
 847         jz      1f
 848         ALLOCPAGES(1)
 849         movl    %esi, %edi
 850         movl    R(IdlePTD), %eax
 851         movl    (%eax), %esi
 852         movl    %edi, (%eax)
 853         movl    $PAGE_SIZE, %ecx
 854         cld
 855         rep
 856         movsb
 857 1:
 858 #endif
 859
 860 /*
 861  * For the non-PSE case, install PDEs for PTs covering the KVA.
 862  * For the PSE case, do the same, but clobber the ones corresponding
 863  * to the kernel (from btext to KERNend) with 4M (2M for PAE) ('PS')
 864  * PDEs immediately after.
 865  */
 866         movl    R(KPTphys), %eax
 867         movl    $KPTDI, %ebx
 868         movl    $NKPT, %ecx
 869         fillkpt(R(IdlePTD), $PG_RW)
 870         cmpl    $0,R(pseflag)
 871         je      done_pde
 872
 873         movl    R(KERNend), %ecx
 874         movl    $KERNLOAD, %eax
 875         subl    %eax, %ecx
 876         shrl    $PDRSHIFT, %ecx
 877         movl    $(KPTDI+(KERNLOAD/(1 << PDRSHIFT))), %ebx
 878         shll    $PDESHIFT, %ebx
 879         addl    R(IdlePTD), %ebx
 880         orl     $(PG_V|PG_RW|PG_PS), %eax
 881 1:      movl    %eax, (%ebx)
 882         addl    $(1 << PDRSHIFT), %eax
 883         addl    $PDESIZE, %ebx
 884         loop    1b
 885
 886 done_pde:
 887 /* install a pde recursively mapping page directory as a page table */
 888         movl    R(IdlePTD), %eax
 889         movl    $PTDPTDI, %ebx
 890         movl    $NPGPTD,%ecx
 891         fillkpt(R(IdlePTD), $PG_RW)
 892
 893 #if defined(PAE) || defined(PAE_TABLES)
 894         movl    R(IdlePTD), %eax
 895         xorl    %ebx, %ebx
 896         movl    $NPGPTD, %ecx
 897         fillkpt(R(IdlePDPT), $0x0)
 898 #endif
 899
 900         ret
 901
 902 #ifdef XENHVM
 903 /* Xen Hypercall page */
 904         .text
 905 .p2align PAGE_SHIFT, 0x90       /* Hypercall_page needs to be PAGE aligned */
 906
 907 NON_GPROF_ENTRY(hypercall_page)
 908         .skip   0x1000, 0x90    /* Fill with "nop"s */
 909 #endif