The Design and Implementation of the FreeBSD Operating System, Second Edition
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  * 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: stable/9/sys/i386/i386/locore.s 213455 2010-10-05 17:06:51Z alc $
   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 #ifdef PAE
  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 #ifdef PAE
  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                         /* bootstrap stack end location */
  306         leal    (KSTACK_PAGES*PAGE_SIZE-PCB_SIZE)(%eax),%esp
  307 
  308         xorl    %ebp,%ebp               /* mark end of frames */
  309 
  310 #ifdef PAE
  311         movl    IdlePDPT,%esi
  312 #else
  313         movl    IdlePTD,%esi
  314 #endif
  315         movl    %esi,(KSTACK_PAGES*PAGE_SIZE-PCB_SIZE+PCB_CR3)(%eax)
  316 
  317         pushl   physfree                /* value of first for init386(first) */
  318         call    init386                 /* wire 386 chip for unix operation */
  319 
  320         /*
  321          * Clean up the stack in a way that db_numargs() understands, so
  322          * that backtraces in ddb don't underrun the stack.  Traps for
  323          * inaccessible memory are more fatal than usual this early.
  324          */
  325         addl    $4,%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 #ifdef PAE
  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(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!  DON'T BLINDLY REMOVE
  779  * THIS!  SMP needs the page table to be there to map the kernel P==V.
  780  */
  781         xorl    %eax, %eax
  782         movl    R(KERNend),%ecx
  783         shrl    $PAGE_SHIFT,%ecx
  784         fillkptphys($PG_RW)
  785 
  786 /* Map page table pages. */
  787         movl    R(KPTphys),%eax
  788         movl    $NKPT,%ecx
  789         fillkptphys($PG_RW)
  790 
  791 /* Map page directory. */
  792 #ifdef PAE
  793         movl    R(IdlePDPT), %eax
  794         movl    $1, %ecx
  795         fillkptphys($PG_RW)
  796 #endif
  797 
  798         movl    R(IdlePTD), %eax
  799         movl    $NPGPTD, %ecx
  800         fillkptphys($PG_RW)
  801 
  802 /* Map proc0's KSTACK in the physical way ... */
  803         movl    R(p0kpa), %eax
  804         movl    $(KSTACK_PAGES), %ecx
  805         fillkptphys($PG_RW)
  806 
  807 /* Map ISA hole */
  808         movl    $ISA_HOLE_START, %eax
  809         movl    $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
  810         fillkptphys($PG_RW)
  811 
  812 /* Map space for the vm86 region */
  813         movl    R(vm86phystk), %eax
  814         movl    $4, %ecx
  815         fillkptphys($PG_RW)
  816 
  817 /* Map page 0 into the vm86 page table */
  818         movl    $0, %eax
  819         movl    $0, %ebx
  820         movl    $1, %ecx
  821         fillkpt(R(vm86pa), $PG_RW|PG_U)
  822 
  823 /* ...likewise for the ISA hole */
  824         movl    $ISA_HOLE_START, %eax
  825         movl    $ISA_HOLE_START>>PAGE_SHIFT, %ebx
  826         movl    $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
  827         fillkpt(R(vm86pa), $PG_RW|PG_U)
  828 
  829 /*
  830  * Create an identity mapping for low physical memory, including the kernel.
  831  * The part of this mapping that covers the first 1 MB of physical memory
  832  * becomes a permanent part of the kernel's address space.  The rest of this
  833  * mapping is destroyed in pmap_bootstrap().  Ordinarily, the same page table
  834  * pages are shared by the identity mapping and the kernel's native mapping.
  835  * However, the permanent identity mapping cannot contain PG_G mappings.
  836  * Thus, if the kernel is loaded within the permanent identity mapping, that
  837  * page table page must be duplicated and not shared.
  838  *
  839  * N.B. Due to errata concerning large pages and physical address zero,
  840  * a PG_PS mapping is not used.
  841  */
  842         movl    R(KPTphys), %eax
  843         xorl    %ebx, %ebx
  844         movl    $NKPT, %ecx
  845         fillkpt(R(IdlePTD), $PG_RW)
  846 #if KERNLOAD < (1 << PDRSHIFT)
  847         testl   $PG_G, R(pgeflag)
  848         jz      1f
  849         ALLOCPAGES(1)
  850         movl    %esi, %edi
  851         movl    R(IdlePTD), %eax
  852         movl    (%eax), %esi
  853         movl    %edi, (%eax)
  854         movl    $PAGE_SIZE, %ecx
  855         cld
  856         rep
  857         movsb
  858 1:      
  859 #endif
  860 
  861 /*
  862  * For the non-PSE case, install PDEs for PTs covering the KVA.
  863  * For the PSE case, do the same, but clobber the ones corresponding
  864  * to the kernel (from btext to KERNend) with 4M (2M for PAE) ('PS')
  865  * PDEs immediately after.
  866  */
  867         movl    R(KPTphys), %eax
  868         movl    $KPTDI, %ebx
  869         movl    $NKPT, %ecx
  870         fillkpt(R(IdlePTD), $PG_RW)
  871         cmpl    $0,R(pseflag)
  872         je      done_pde
  873 
  874         movl    R(KERNend), %ecx
  875         movl    $KERNLOAD, %eax
  876         subl    %eax, %ecx
  877         shrl    $PDRSHIFT, %ecx
  878         movl    $(KPTDI+(KERNLOAD/(1 << PDRSHIFT))), %ebx
  879         shll    $PDESHIFT, %ebx
  880         addl    R(IdlePTD), %ebx
  881         orl     $(PG_V|PG_RW|PG_PS), %eax
  882 1:      movl    %eax, (%ebx)
  883         addl    $(1 << PDRSHIFT), %eax
  884         addl    $PDESIZE, %ebx
  885         loop    1b
  886 
  887 done_pde:
  888 /* install a pde recursively mapping page directory as a page table */
  889         movl    R(IdlePTD), %eax
  890         movl    $PTDPTDI, %ebx
  891         movl    $NPGPTD,%ecx
  892         fillkpt(R(IdlePTD), $PG_RW)
  893 
  894 #ifdef PAE
  895         movl    R(IdlePTD), %eax
  896         xorl    %ebx, %ebx
  897         movl    $NPGPTD, %ecx
  898         fillkpt(R(IdlePDPT), $0x0)
  899 #endif
  900 
  901         ret

Cache object: 495fafad991db57c6c84c2bcfd243f8e


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