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: releng/6.0/sys/i386/i386/locore.s 146263 2005-05-16 09:47:53Z obrien $
   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 #ifdef SMP
   76 /*
   77  * Define layout of per-cpu address space.
   78  * This is "constructed" in locore.s on the BSP and in mp_machdep.c
   79  * for each AP.  DO NOT REORDER THESE WITHOUT UPDATING THE REST!
   80  */
   81         .globl  SMP_prvspace
   82         .set    SMP_prvspace,(MPPTDI << PDRSHIFT)
   83 #endif /* SMP */
   84 
   85 /*
   86  * Compiled KERNBASE location and the kernel load address
   87  */
   88         .globl  kernbase
   89         .set    kernbase,KERNBASE
   90         .globl  kernload
   91         .set    kernload,KERNLOAD
   92 
   93 /*
   94  * Globals
   95  */
   96         .data
   97         ALIGN_DATA                      /* just to be sure */
   98 
   99         .space  0x2000                  /* space for tmpstk - temporary stack */
  100 tmpstk:
  101 
  102         .globl  bootinfo
  103 bootinfo:       .space  BOOTINFO_SIZE   /* bootinfo that we can handle */
  104 
  105                 .globl KERNend
  106 KERNend:        .long   0               /* phys addr end of kernel (just after bss) */
  107 physfree:       .long   0               /* phys addr of next free page */
  108 
  109 #ifdef SMP
  110                 .globl  cpu0prvpage
  111 cpu0pp:         .long   0               /* phys addr cpu0 private pg */
  112 cpu0prvpage:    .long   0               /* relocated version */
  113 
  114                 .globl  SMPpt
  115 SMPptpa:        .long   0               /* phys addr SMP page table */
  116 SMPpt:          .long   0               /* relocated version */
  117 #endif /* SMP */
  118 
  119         .globl  IdlePTD
  120 IdlePTD:        .long   0               /* phys addr of kernel PTD */
  121 
  122 #ifdef PAE
  123         .globl  IdlePDPT
  124 IdlePDPT:       .long   0               /* phys addr of kernel PDPT */
  125 #endif
  126 
  127 #ifdef SMP
  128         .globl  KPTphys
  129 #endif
  130 KPTphys:        .long   0               /* phys addr of kernel page tables */
  131 
  132         .globl  proc0kstack
  133 proc0uarea:     .long   0               /* address of proc 0 uarea (unused)*/
  134 proc0kstack:    .long   0               /* address of proc 0 kstack space */
  135 p0upa:          .long   0               /* phys addr of proc0 UAREA (unused) */
  136 p0kpa:          .long   0               /* phys addr of proc0's STACK */
  137 
  138 vm86phystk:     .long   0               /* PA of vm86/bios stack */
  139 
  140         .globl  vm86paddr, vm86pa
  141 vm86paddr:      .long   0               /* address of vm86 region */
  142 vm86pa:         .long   0               /* phys addr of vm86 region */
  143 
  144 #ifdef PC98
  145         .globl  pc98_system_parameter
  146 pc98_system_parameter:
  147         .space  0x240
  148 #endif
  149 
  150 /**********************************************************************
  151  *
  152  * Some handy macros
  153  *
  154  */
  155 
  156 #define R(foo) ((foo)-KERNBASE)
  157 
  158 #define ALLOCPAGES(foo) \
  159         movl    R(physfree), %esi ; \
  160         movl    $((foo)*PAGE_SIZE), %eax ; \
  161         addl    %esi, %eax ; \
  162         movl    %eax, R(physfree) ; \
  163         movl    %esi, %edi ; \
  164         movl    $((foo)*PAGE_SIZE),%ecx ; \
  165         xorl    %eax,%eax ; \
  166         cld ; \
  167         rep ; \
  168         stosb
  169 
  170 /*
  171  * fillkpt
  172  *      eax = page frame address
  173  *      ebx = index into page table
  174  *      ecx = how many pages to map
  175  *      base = base address of page dir/table
  176  *      prot = protection bits
  177  */
  178 #define fillkpt(base, prot)               \
  179         shll    $PTESHIFT,%ebx          ; \
  180         addl    base,%ebx               ; \
  181         orl     $PG_V,%eax              ; \
  182         orl     prot,%eax               ; \
  183 1:      movl    %eax,(%ebx)             ; \
  184         addl    $PAGE_SIZE,%eax         ; /* increment physical address */ \
  185         addl    $PTESIZE,%ebx           ; /* next pte */ \
  186         loop    1b
  187 
  188 /*
  189  * fillkptphys(prot)
  190  *      eax = physical address
  191  *      ecx = how many pages to map
  192  *      prot = protection bits
  193  */
  194 #define fillkptphys(prot)                 \
  195         movl    %eax, %ebx              ; \
  196         shrl    $PAGE_SHIFT, %ebx       ; \
  197         fillkpt(R(KPTphys), prot)
  198 
  199         .text
  200 /**********************************************************************
  201  *
  202  * This is where the bootblocks start us, set the ball rolling...
  203  *
  204  */
  205 NON_GPROF_ENTRY(btext)
  206 
  207 #ifdef PC98
  208         /* save SYSTEM PARAMETER for resume (NS/T or other) */
  209         movl    $0xa1400,%esi
  210         movl    $R(pc98_system_parameter),%edi
  211         movl    $0x0240,%ecx
  212         cld
  213         rep
  214         movsb
  215 #else   /* IBM-PC */
  216 /* Tell the bios to warmboot next time */
  217         movw    $0x1234,0x472
  218 #endif  /* PC98 */
  219 
  220 /* Set up a real frame in case the double return in newboot is executed. */
  221         pushl   %ebp
  222         movl    %esp, %ebp
  223 
  224 /* Don't trust what the BIOS gives for eflags. */
  225         pushl   $PSL_KERNEL
  226         popfl
  227 
  228 /*
  229  * Don't trust what the BIOS gives for %fs and %gs.  Trust the bootstrap
  230  * to set %cs, %ds, %es and %ss.
  231  */
  232         mov     %ds, %ax
  233         mov     %ax, %fs
  234         mov     %ax, %gs
  235 
  236 /*
  237  * Clear the bss.  Not all boot programs do it, and it is our job anyway.
  238  *
  239  * XXX we don't check that there is memory for our bss and page tables
  240  * before using it.
  241  *
  242  * Note: we must be careful to not overwrite an active gdt or idt.  They
  243  * inactive from now until we switch to new ones, since we don't load any
  244  * more segment registers or permit interrupts until after the switch.
  245  */
  246         movl    $R(end),%ecx
  247         movl    $R(edata),%edi
  248         subl    %edi,%ecx
  249         xorl    %eax,%eax
  250         cld
  251         rep
  252         stosb
  253 
  254         call    recover_bootinfo
  255 
  256 /* Get onto a stack that we can trust. */
  257 /*
  258  * XXX this step is delayed in case recover_bootinfo needs to return via
  259  * the old stack, but it need not be, since recover_bootinfo actually
  260  * returns via the old frame.
  261  */
  262         movl    $R(tmpstk),%esp
  263 
  264 #ifdef PC98
  265         /* pc98_machine_type & M_EPSON_PC98 */
  266         testb   $0x02,R(pc98_system_parameter)+220
  267         jz      3f
  268         /* epson_machine_id <= 0x0b */
  269         cmpb    $0x0b,R(pc98_system_parameter)+224
  270         ja      3f
  271 
  272         /* count up memory */
  273         movl    $0x100000,%eax          /* next, talley remaining memory */
  274         movl    $0xFFF-0x100,%ecx
  275 1:      movl    0(%eax),%ebx            /* save location to check */
  276         movl    $0xa55a5aa5,0(%eax)     /* write test pattern */
  277         cmpl    $0xa55a5aa5,0(%eax)     /* does not check yet for rollover */
  278         jne     2f
  279         movl    %ebx,0(%eax)            /* restore memory */
  280         addl    $PAGE_SIZE,%eax
  281         loop    1b
  282 2:      subl    $0x100000,%eax
  283         shrl    $17,%eax
  284         movb    %al,R(pc98_system_parameter)+1
  285 3:
  286 
  287         movw    R(pc98_system_parameter+0x86),%ax
  288         movw    %ax,R(cpu_id)
  289 #endif
  290 
  291         call    identify_cpu
  292         call    create_pagetables
  293 
  294 /*
  295  * If the CPU has support for VME, turn it on.
  296  */ 
  297         testl   $CPUID_VME, R(cpu_feature)
  298         jz      1f
  299         movl    %cr4, %eax
  300         orl     $CR4_VME, %eax
  301         movl    %eax, %cr4
  302 1:
  303 
  304 /* Now enable paging */
  305 #ifdef PAE
  306         movl    R(IdlePDPT), %eax
  307         movl    %eax, %cr3
  308         movl    %cr4, %eax
  309         orl     $CR4_PAE, %eax
  310         movl    %eax, %cr4
  311 #else
  312         movl    R(IdlePTD), %eax
  313         movl    %eax,%cr3               /* load ptd addr into mmu */
  314 #endif
  315         movl    %cr0,%eax               /* get control word */
  316         orl     $CR0_PE|CR0_PG,%eax     /* enable paging */
  317         movl    %eax,%cr0               /* and let's page NOW! */
  318 
  319         pushl   $begin                  /* jump to high virtualized address */
  320         ret
  321 
  322 /* now running relocated at KERNBASE where the system is linked to run */
  323 begin:
  324         /* set up bootstrap stack */
  325         movl    proc0kstack,%eax        /* location of in-kernel stack */
  326                         /* bootstrap stack end location */
  327         leal    (KSTACK_PAGES*PAGE_SIZE-PCB_SIZE)(%eax),%esp
  328 
  329         xorl    %ebp,%ebp               /* mark end of frames */
  330 
  331 #ifdef PAE
  332         movl    IdlePDPT,%esi
  333 #else
  334         movl    IdlePTD,%esi
  335 #endif
  336         movl    %esi,(KSTACK_PAGES*PAGE_SIZE-PCB_SIZE+PCB_CR3)(%eax)
  337 
  338         pushl   physfree                /* value of first for init386(first) */
  339         call    init386                 /* wire 386 chip for unix operation */
  340 
  341         /*
  342          * Clean up the stack in a way that db_numargs() understands, so
  343          * that backtraces in ddb don't underrun the stack.  Traps for
  344          * inaccessible memory are more fatal than usual this early.
  345          */
  346         addl    $4,%esp
  347 
  348         call    mi_startup              /* autoconfiguration, mountroot etc */
  349         /* NOTREACHED */
  350         addl    $0,%esp                 /* for db_numargs() again */
  351 
  352 /*
  353  * Signal trampoline, copied to top of user stack
  354  */
  355 NON_GPROF_ENTRY(sigcode)
  356         calll   *SIGF_HANDLER(%esp)
  357         leal    SIGF_UC(%esp),%eax      /* get ucontext */
  358         pushl   %eax
  359         testl   $PSL_VM,UC_EFLAGS(%eax)
  360         jne     1f
  361         movl    UC_GS(%eax),%gs         /* restore %gs */
  362 1:
  363         movl    $SYS_sigreturn,%eax
  364         pushl   %eax                    /* junk to fake return addr. */
  365         int     $0x80                   /* enter kernel with args */
  366                                         /* on stack */
  367 1:
  368         jmp     1b
  369 
  370 #ifdef COMPAT_FREEBSD4
  371         ALIGN_TEXT
  372 freebsd4_sigcode:
  373         calll   *SIGF_HANDLER(%esp)
  374         leal    SIGF_UC4(%esp),%eax     /* get ucontext */
  375         pushl   %eax
  376         testl   $PSL_VM,UC4_EFLAGS(%eax)
  377         jne     1f
  378         movl    UC4_GS(%eax),%gs        /* restore %gs */
  379 1:
  380         movl    $344,%eax               /* 4.x SYS_sigreturn */
  381         pushl   %eax                    /* junk to fake return addr. */
  382         int     $0x80                   /* enter kernel with args */
  383                                         /* on stack */
  384 1:
  385         jmp     1b
  386 #endif
  387 
  388 #ifdef COMPAT_43
  389         ALIGN_TEXT
  390 osigcode:
  391         call    *SIGF_HANDLER(%esp)     /* call signal handler */
  392         lea     SIGF_SC(%esp),%eax      /* get sigcontext */
  393         pushl   %eax
  394         testl   $PSL_VM,SC_PS(%eax)
  395         jne     9f
  396         movl    SC_GS(%eax),%gs         /* restore %gs */
  397 9:
  398         movl    $103,%eax               /* 3.x SYS_sigreturn */
  399         pushl   %eax                    /* junk to fake return addr. */
  400         int     $0x80                   /* enter kernel with args */
  401 0:      jmp     0b
  402 #endif /* COMPAT_43 */
  403 
  404         ALIGN_TEXT
  405 esigcode:
  406 
  407         .data
  408         .globl  szsigcode
  409 szsigcode:
  410         .long   esigcode-sigcode
  411 #ifdef COMPAT_FREEBSD4
  412         .globl  szfreebsd4_sigcode
  413 szfreebsd4_sigcode:
  414         .long   esigcode-freebsd4_sigcode
  415 #endif
  416 #ifdef COMPAT_43
  417         .globl  szosigcode
  418 szosigcode:
  419         .long   esigcode-osigcode
  420 #endif
  421         .text
  422 
  423 /**********************************************************************
  424  *
  425  * Recover the bootinfo passed to us from the boot program
  426  *
  427  */
  428 recover_bootinfo:
  429         /*
  430          * This code is called in different ways depending on what loaded
  431          * and started the kernel.  This is used to detect how we get the
  432          * arguments from the other code and what we do with them.
  433          *
  434          * Old disk boot blocks:
  435          *      (*btext)(howto, bootdev, cyloffset, esym);
  436          *      [return address == 0, and can NOT be returned to]
  437          *      [cyloffset was not supported by the FreeBSD boot code
  438          *       and always passed in as 0]
  439          *      [esym is also known as total in the boot code, and
  440          *       was never properly supported by the FreeBSD boot code]
  441          *
  442          * Old diskless netboot code:
  443          *      (*btext)(0,0,0,0,&nfsdiskless,0,0,0);
  444          *      [return address != 0, and can NOT be returned to]
  445          *      If we are being booted by this code it will NOT work,
  446          *      so we are just going to halt if we find this case.
  447          *
  448          * New uniform boot code:
  449          *      (*btext)(howto, bootdev, 0, 0, 0, &bootinfo)
  450          *      [return address != 0, and can be returned to]
  451          *
  452          * There may seem to be a lot of wasted arguments in here, but
  453          * that is so the newer boot code can still load very old kernels
  454          * and old boot code can load new kernels.
  455          */
  456 
  457         /*
  458          * The old style disk boot blocks fake a frame on the stack and
  459          * did an lret to get here.  The frame on the stack has a return
  460          * address of 0.
  461          */
  462         cmpl    $0,4(%ebp)
  463         je      olddiskboot
  464 
  465         /*
  466          * We have some form of return address, so this is either the
  467          * old diskless netboot code, or the new uniform code.  That can
  468          * be detected by looking at the 5th argument, if it is 0
  469          * we are being booted by the new uniform boot code.
  470          */
  471         cmpl    $0,24(%ebp)
  472         je      newboot
  473 
  474         /*
  475          * Seems we have been loaded by the old diskless boot code, we
  476          * don't stand a chance of running as the diskless structure
  477          * changed considerably between the two, so just halt.
  478          */
  479          hlt
  480 
  481         /*
  482          * We have been loaded by the new uniform boot code.
  483          * Let's check the bootinfo version, and if we do not understand
  484          * it we return to the loader with a status of 1 to indicate this error
  485          */
  486 newboot:
  487         movl    28(%ebp),%ebx           /* &bootinfo.version */
  488         movl    BI_VERSION(%ebx),%eax
  489         cmpl    $1,%eax                 /* We only understand version 1 */
  490         je      1f
  491         movl    $1,%eax                 /* Return status */
  492         leave
  493         /*
  494          * XXX this returns to our caller's caller (as is required) since
  495          * we didn't set up a frame and our caller did.
  496          */
  497         ret
  498 
  499 1:
  500         /*
  501          * If we have a kernelname copy it in
  502          */
  503         movl    BI_KERNELNAME(%ebx),%esi
  504         cmpl    $0,%esi
  505         je      2f                      /* No kernelname */
  506         movl    $MAXPATHLEN,%ecx        /* Brute force!!! */
  507         movl    $R(kernelname),%edi
  508         cmpb    $'/',(%esi)             /* Make sure it starts with a slash */
  509         je      1f
  510         movb    $'/',(%edi)
  511         incl    %edi
  512         decl    %ecx
  513 1:
  514         cld
  515         rep
  516         movsb
  517 
  518 2:
  519         /*
  520          * Determine the size of the boot loader's copy of the bootinfo
  521          * struct.  This is impossible to do properly because old versions
  522          * of the struct don't contain a size field and there are 2 old
  523          * versions with the same version number.
  524          */
  525         movl    $BI_ENDCOMMON,%ecx      /* prepare for sizeless version */
  526         testl   $RB_BOOTINFO,8(%ebp)    /* bi_size (and bootinfo) valid? */
  527         je      got_bi_size             /* no, sizeless version */
  528         movl    BI_SIZE(%ebx),%ecx
  529 got_bi_size:
  530 
  531         /*
  532          * Copy the common part of the bootinfo struct
  533          */
  534         movl    %ebx,%esi
  535         movl    $R(bootinfo),%edi
  536         cmpl    $BOOTINFO_SIZE,%ecx
  537         jbe     got_common_bi_size
  538         movl    $BOOTINFO_SIZE,%ecx
  539 got_common_bi_size:
  540         cld
  541         rep
  542         movsb
  543 
  544 #ifdef NFS_ROOT
  545 #ifndef BOOTP_NFSV3
  546         /*
  547          * If we have a nfs_diskless structure copy it in
  548          */
  549         movl    BI_NFS_DISKLESS(%ebx),%esi
  550         cmpl    $0,%esi
  551         je      olddiskboot
  552         movl    $R(nfs_diskless),%edi
  553         movl    $NFSDISKLESS_SIZE,%ecx
  554         cld
  555         rep
  556         movsb
  557         movl    $R(nfs_diskless_valid),%edi
  558         movl    $1,(%edi)
  559 #endif
  560 #endif
  561 
  562         /*
  563          * The old style disk boot.
  564          *      (*btext)(howto, bootdev, cyloffset, esym);
  565          * Note that the newer boot code just falls into here to pick
  566          * up howto and bootdev, cyloffset and esym are no longer used
  567          */
  568 olddiskboot:
  569         movl    8(%ebp),%eax
  570         movl    %eax,R(boothowto)
  571         movl    12(%ebp),%eax
  572         movl    %eax,R(bootdev)
  573 
  574         ret
  575 
  576 
  577 /**********************************************************************
  578  *
  579  * Identify the CPU and initialize anything special about it
  580  *
  581  */
  582 identify_cpu:
  583 
  584         /* Try to toggle alignment check flag; does not exist on 386. */
  585         pushfl
  586         popl    %eax
  587         movl    %eax,%ecx
  588         orl     $PSL_AC,%eax
  589         pushl   %eax
  590         popfl
  591         pushfl
  592         popl    %eax
  593         xorl    %ecx,%eax
  594         andl    $PSL_AC,%eax
  595         pushl   %ecx
  596         popfl
  597 
  598         testl   %eax,%eax
  599         jnz     try486
  600 
  601         /* NexGen CPU does not have aligment check flag. */
  602         pushfl
  603         movl    $0x5555, %eax
  604         xorl    %edx, %edx
  605         movl    $2, %ecx
  606         clc
  607         divl    %ecx
  608         jz      trynexgen
  609         popfl
  610         movl    $CPU_386,R(cpu)
  611         jmp     3f
  612 
  613 trynexgen:
  614         popfl
  615         movl    $CPU_NX586,R(cpu)
  616         movl    $0x4778654e,R(cpu_vendor)       # store vendor string
  617         movl    $0x72446e65,R(cpu_vendor+4)
  618         movl    $0x6e657669,R(cpu_vendor+8)
  619         movl    $0,R(cpu_vendor+12)
  620         jmp     3f
  621 
  622 try486: /* Try to toggle identification flag; does not exist on early 486s. */
  623         pushfl
  624         popl    %eax
  625         movl    %eax,%ecx
  626         xorl    $PSL_ID,%eax
  627         pushl   %eax
  628         popfl
  629         pushfl
  630         popl    %eax
  631         xorl    %ecx,%eax
  632         andl    $PSL_ID,%eax
  633         pushl   %ecx
  634         popfl
  635 
  636         testl   %eax,%eax
  637         jnz     trycpuid
  638         movl    $CPU_486,R(cpu)
  639 
  640         /*
  641          * Check Cyrix CPU
  642          * Cyrix CPUs do not change the undefined flags following
  643          * execution of the divide instruction which divides 5 by 2.
  644          *
  645          * Note: CPUID is enabled on M2, so it passes another way.
  646          */
  647         pushfl
  648         movl    $0x5555, %eax
  649         xorl    %edx, %edx
  650         movl    $2, %ecx
  651         clc
  652         divl    %ecx
  653         jnc     trycyrix
  654         popfl
  655         jmp     3f              /* You may use Intel CPU. */
  656 
  657 trycyrix:
  658         popfl
  659         /*
  660          * IBM Bluelighting CPU also doesn't change the undefined flags.
  661          * Because IBM doesn't disclose the information for Bluelighting
  662          * CPU, we couldn't distinguish it from Cyrix's (including IBM
  663          * brand of Cyrix CPUs).
  664          */
  665         movl    $0x69727943,R(cpu_vendor)       # store vendor string
  666         movl    $0x736e4978,R(cpu_vendor+4)
  667         movl    $0x64616574,R(cpu_vendor+8)
  668         jmp     3f
  669 
  670 trycpuid:       /* Use the `cpuid' instruction. */
  671         xorl    %eax,%eax
  672         cpuid                                   # cpuid 0
  673         movl    %eax,R(cpu_high)                # highest capability
  674         movl    %ebx,R(cpu_vendor)              # store vendor string
  675         movl    %edx,R(cpu_vendor+4)
  676         movl    %ecx,R(cpu_vendor+8)
  677         movb    $0,R(cpu_vendor+12)
  678 
  679         movl    $1,%eax
  680         cpuid                                   # cpuid 1
  681         movl    %eax,R(cpu_id)                  # store cpu_id
  682         movl    %ebx,R(cpu_procinfo)            # store cpu_procinfo
  683         movl    %edx,R(cpu_feature)             # store cpu_feature
  684         movl    %ecx,R(cpu_feature2)            # store cpu_feature2
  685         rorl    $8,%eax                         # extract family type
  686         andl    $15,%eax
  687         cmpl    $5,%eax
  688         jae     1f
  689 
  690         /* less than Pentium; must be 486 */
  691         movl    $CPU_486,R(cpu)
  692         jmp     3f
  693 1:
  694         /* a Pentium? */
  695         cmpl    $5,%eax
  696         jne     2f
  697         movl    $CPU_586,R(cpu)
  698         jmp     3f
  699 2:
  700         /* Greater than Pentium...call it a Pentium Pro */
  701         movl    $CPU_686,R(cpu)
  702 3:
  703         ret
  704 
  705 
  706 /**********************************************************************
  707  *
  708  * Create the first page directory and its page tables.
  709  *
  710  */
  711 
  712 create_pagetables:
  713 
  714 /* Find end of kernel image (rounded up to a page boundary). */
  715         movl    $R(_end),%esi
  716 
  717 /* Include symbols, if any. */
  718         movl    R(bootinfo+BI_ESYMTAB),%edi
  719         testl   %edi,%edi
  720         je      over_symalloc
  721         movl    %edi,%esi
  722         movl    $KERNBASE,%edi
  723         addl    %edi,R(bootinfo+BI_SYMTAB)
  724         addl    %edi,R(bootinfo+BI_ESYMTAB)
  725 over_symalloc:
  726 
  727 /* If we are told where the end of the kernel space is, believe it. */
  728         movl    R(bootinfo+BI_KERNEND),%edi
  729         testl   %edi,%edi
  730         je      no_kernend
  731         movl    %edi,%esi
  732 no_kernend:
  733 
  734         addl    $PDRMASK,%esi           /* Play conservative for now, and */
  735         andl    $~PDRMASK,%esi          /*   ... wrap to next 4M. */
  736         movl    %esi,R(KERNend)         /* save end of kernel */
  737         movl    %esi,R(physfree)        /* next free page is at end of kernel */
  738 
  739 /* Allocate Kernel Page Tables */
  740         ALLOCPAGES(NKPT)
  741         movl    %esi,R(KPTphys)
  742 
  743 /* Allocate Page Table Directory */
  744 #ifdef PAE
  745         /* XXX only need 32 bytes (easier for now) */
  746         ALLOCPAGES(1)
  747         movl    %esi,R(IdlePDPT)
  748 #endif
  749         ALLOCPAGES(NPGPTD)
  750         movl    %esi,R(IdlePTD)
  751 
  752 /* Allocate KSTACK */
  753         ALLOCPAGES(KSTACK_PAGES)
  754         movl    %esi,R(p0kpa)
  755         addl    $KERNBASE, %esi
  756         movl    %esi, R(proc0kstack)
  757 
  758         ALLOCPAGES(1)                   /* vm86/bios stack */
  759         movl    %esi,R(vm86phystk)
  760 
  761         ALLOCPAGES(3)                   /* pgtable + ext + IOPAGES */
  762         movl    %esi,R(vm86pa)
  763         addl    $KERNBASE, %esi
  764         movl    %esi, R(vm86paddr)
  765 
  766 #ifdef SMP
  767 /* Allocate cpu0's private data page */
  768         ALLOCPAGES(1)
  769         movl    %esi,R(cpu0pp)
  770         addl    $KERNBASE, %esi
  771         movl    %esi, R(cpu0prvpage)    /* relocated to KVM space */
  772 
  773 /* Allocate SMP page table page */
  774         ALLOCPAGES(1)
  775         movl    %esi,R(SMPptpa)
  776         addl    $KERNBASE, %esi
  777         movl    %esi, R(SMPpt)          /* relocated to KVM space */
  778 #endif  /* SMP */
  779 
  780 /* Map page zero read-write so bios32 calls can use it */
  781         xorl    %eax, %eax
  782         movl    $PG_RW,%edx
  783         movl    $1,%ecx
  784         fillkptphys(%edx)
  785 
  786 /* Map read-only from page 1 to the beginning of the kernel text section */
  787         movl    $PAGE_SIZE, %eax
  788         xorl    %edx,%edx
  789         movl    $R(btext),%ecx
  790         addl    $PAGE_MASK,%ecx
  791         subl    %eax,%ecx
  792         shrl    $PAGE_SHIFT,%ecx
  793         fillkptphys(%edx)
  794 
  795 /*
  796  * Enable PSE and PGE.
  797  */
  798 #ifndef DISABLE_PSE
  799         testl   $CPUID_PSE, R(cpu_feature)
  800         jz      1f
  801         movl    $PG_PS, R(pseflag)
  802         movl    %cr4, %eax
  803         orl     $CR4_PSE, %eax
  804         movl    %eax, %cr4
  805 1:
  806 #endif
  807 #ifndef DISABLE_PG_G
  808         testl   $CPUID_PGE, R(cpu_feature)
  809         jz      2f
  810         movl    $PG_G, R(pgeflag)
  811         movl    %cr4, %eax
  812         orl     $CR4_PGE, %eax
  813         movl    %eax, %cr4
  814 2:
  815 #endif
  816 
  817 /*
  818  * Write page tables for the kernel starting at btext and
  819  * until the end.  Make sure to map read+write.  We do this even
  820  * if we've enabled PSE above, we'll just switch the corresponding kernel
  821  * PDEs before we turn on paging.
  822  *
  823  * XXX: We waste some pages here in the PSE case!  DON'T BLINDLY REMOVE
  824  * THIS!  SMP needs the page table to be there to map the kernel P==V.
  825  */
  826         movl    $R(btext),%eax
  827         addl    $PAGE_MASK, %eax
  828         andl    $~PAGE_MASK, %eax
  829         movl    $PG_RW,%edx
  830         movl    R(KERNend),%ecx
  831         subl    %eax,%ecx
  832         shrl    $PAGE_SHIFT,%ecx
  833         fillkptphys(%edx)
  834 
  835 /* Map page directory. */
  836 #ifdef PAE
  837         movl    R(IdlePDPT), %eax
  838         movl    $1, %ecx
  839         fillkptphys($PG_RW)
  840 #endif
  841 
  842         movl    R(IdlePTD), %eax
  843         movl    $NPGPTD, %ecx
  844         fillkptphys($PG_RW)
  845 
  846 /* Map proc0's KSTACK in the physical way ... */
  847         movl    R(p0kpa), %eax
  848         movl    $(KSTACK_PAGES), %ecx
  849         fillkptphys($PG_RW)
  850 
  851 /* Map ISA hole */
  852         movl    $ISA_HOLE_START, %eax
  853         movl    $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
  854         fillkptphys($PG_RW)
  855 
  856 /* Map space for the vm86 region */
  857         movl    R(vm86phystk), %eax
  858         movl    $4, %ecx
  859         fillkptphys($PG_RW)
  860 
  861 /* Map page 0 into the vm86 page table */
  862         movl    $0, %eax
  863         movl    $0, %ebx
  864         movl    $1, %ecx
  865         fillkpt(R(vm86pa), $PG_RW|PG_U)
  866 
  867 /* ...likewise for the ISA hole */
  868         movl    $ISA_HOLE_START, %eax
  869         movl    $ISA_HOLE_START>>PAGE_SHIFT, %ebx
  870         movl    $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
  871         fillkpt(R(vm86pa), $PG_RW|PG_U)
  872 
  873 #ifdef SMP
  874 /* Map cpu0's private page into global kmem (4K @ cpu0prvpage) */
  875         movl    R(cpu0pp), %eax
  876         movl    $1, %ecx
  877         fillkptphys($PG_RW)
  878 
  879 /* Map SMP page table page into global kmem FWIW */
  880         movl    R(SMPptpa), %eax
  881         movl    $1, %ecx
  882         fillkptphys($PG_RW)
  883 
  884 /* Map the private page into the SMP page table */
  885         movl    R(cpu0pp), %eax
  886         movl    $0, %ebx                /* pte offset = 0 */
  887         movl    $1, %ecx                /* one private page coming right up */
  888         fillkpt(R(SMPptpa), $PG_RW)
  889 
  890 /* ... and put the page table table in the pde. */
  891         movl    R(SMPptpa), %eax
  892         movl    $MPPTDI, %ebx
  893         movl    $1, %ecx
  894         fillkpt(R(IdlePTD), $PG_RW)
  895 
  896 /* Fakeup VA for the local apic to allow early traps. */
  897         ALLOCPAGES(1)
  898         movl    %esi, %eax
  899         movl    $(NPTEPG-1), %ebx       /* pte offset = NTEPG-1 */
  900         movl    $1, %ecx                /* one private pt coming right up */
  901         fillkpt(R(SMPptpa), $PG_RW)
  902 #endif  /* SMP */
  903 
  904 /* install a pde for temporary double map of bottom of VA */
  905         movl    R(KPTphys), %eax
  906         xorl    %ebx, %ebx
  907         movl    $NKPT, %ecx
  908         fillkpt(R(IdlePTD), $PG_RW)
  909 
  910 /*
  911  * For the non-PSE case, install PDEs for PTs covering the kernel.
  912  * For the PSE case, do the same, but clobber the ones corresponding
  913  * to the kernel (from btext to KERNend) with 4M ('PS') PDEs immediately
  914  * after.
  915  */
  916         movl    R(KPTphys), %eax
  917         movl    $KPTDI, %ebx
  918         movl    $NKPT, %ecx
  919         fillkpt(R(IdlePTD), $PG_RW)
  920         cmpl    $0,R(pseflag)
  921         je      done_pde
  922 
  923         movl    R(KERNend), %ecx
  924         movl    $KERNLOAD, %eax
  925         subl    %eax, %ecx
  926         shrl    $PDRSHIFT, %ecx
  927         movl    $(KPTDI+(KERNLOAD/(1 << PDRSHIFT))), %ebx
  928         shll    $PDESHIFT, %ebx
  929         addl    R(IdlePTD), %ebx
  930         orl     $(PG_V|PG_RW|PG_PS), %eax
  931 1:      movl    %eax, (%ebx)
  932         addl    $(1 << PDRSHIFT), %eax
  933         addl    $PDESIZE, %ebx
  934         loop    1b
  935 
  936 done_pde:
  937 /* install a pde recursively mapping page directory as a page table */
  938         movl    R(IdlePTD), %eax
  939         movl    $PTDPTDI, %ebx
  940         movl    $NPGPTD,%ecx
  941         fillkpt(R(IdlePTD), $PG_RW)
  942 
  943 #ifdef PAE
  944         movl    R(IdlePTD), %eax
  945         xorl    %ebx, %ebx
  946         movl    $NPGPTD, %ecx
  947         fillkpt(R(IdlePDPT), $0x0)
  948 #endif
  949 
  950         ret

Cache object: 984c9d797e4bdc45dbc8c5804c2221af


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