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/6.4/sys/i386/i386/locore.s 181131 2008-08-01 20:31:07Z jhb $
   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 #ifdef SMP
  108         .globl  KPTphys
  109 #endif
  110 KPTphys:        .long   0               /* phys addr of kernel page tables */
  111 
  112         .globl  proc0kstack
  113 proc0uarea:     .long   0               /* address of proc 0 uarea (unused)*/
  114 proc0kstack:    .long   0               /* address of proc 0 kstack space */
  115 p0upa:          .long   0               /* phys addr of proc0 UAREA (unused) */
  116 p0kpa:          .long   0               /* phys addr of proc0's STACK */
  117 
  118 vm86phystk:     .long   0               /* PA of vm86/bios stack */
  119 
  120         .globl  vm86paddr, vm86pa
  121 vm86paddr:      .long   0               /* address of vm86 region */
  122 vm86pa:         .long   0               /* phys addr of vm86 region */
  123 
  124 #ifdef PC98
  125         .globl  pc98_system_parameter
  126 pc98_system_parameter:
  127         .space  0x240
  128 #endif
  129 
  130 /**********************************************************************
  131  *
  132  * Some handy macros
  133  *
  134  */
  135 
  136 #define R(foo) ((foo)-KERNBASE)
  137 
  138 #define ALLOCPAGES(foo) \
  139         movl    R(physfree), %esi ; \
  140         movl    $((foo)*PAGE_SIZE), %eax ; \
  141         addl    %esi, %eax ; \
  142         movl    %eax, R(physfree) ; \
  143         movl    %esi, %edi ; \
  144         movl    $((foo)*PAGE_SIZE),%ecx ; \
  145         xorl    %eax,%eax ; \
  146         cld ; \
  147         rep ; \
  148         stosb
  149 
  150 /*
  151  * fillkpt
  152  *      eax = page frame address
  153  *      ebx = index into page table
  154  *      ecx = how many pages to map
  155  *      base = base address of page dir/table
  156  *      prot = protection bits
  157  */
  158 #define fillkpt(base, prot)               \
  159         shll    $PTESHIFT,%ebx          ; \
  160         addl    base,%ebx               ; \
  161         orl     $PG_V,%eax              ; \
  162         orl     prot,%eax               ; \
  163 1:      movl    %eax,(%ebx)             ; \
  164         addl    $PAGE_SIZE,%eax         ; /* increment physical address */ \
  165         addl    $PTESIZE,%ebx           ; /* next pte */ \
  166         loop    1b
  167 
  168 /*
  169  * fillkptphys(prot)
  170  *      eax = physical address
  171  *      ecx = how many pages to map
  172  *      prot = protection bits
  173  */
  174 #define fillkptphys(prot)                 \
  175         movl    %eax, %ebx              ; \
  176         shrl    $PAGE_SHIFT, %ebx       ; \
  177         fillkpt(R(KPTphys), prot)
  178 
  179         .text
  180 /**********************************************************************
  181  *
  182  * This is where the bootblocks start us, set the ball rolling...
  183  *
  184  */
  185 NON_GPROF_ENTRY(btext)
  186 
  187 #ifdef PC98
  188         /* save SYSTEM PARAMETER for resume (NS/T or other) */
  189         movl    $0xa1400,%esi
  190         movl    $R(pc98_system_parameter),%edi
  191         movl    $0x0240,%ecx
  192         cld
  193         rep
  194         movsb
  195 #else   /* IBM-PC */
  196 /* Tell the bios to warmboot next time */
  197         movw    $0x1234,0x472
  198 #endif  /* PC98 */
  199 
  200 /* Set up a real frame in case the double return in newboot is executed. */
  201         pushl   %ebp
  202         movl    %esp, %ebp
  203 
  204 /* Don't trust what the BIOS gives for eflags. */
  205         pushl   $PSL_KERNEL
  206         popfl
  207 
  208 /*
  209  * Don't trust what the BIOS gives for %fs and %gs.  Trust the bootstrap
  210  * to set %cs, %ds, %es and %ss.
  211  */
  212         mov     %ds, %ax
  213         mov     %ax, %fs
  214         mov     %ax, %gs
  215 
  216 /*
  217  * Clear the bss.  Not all boot programs do it, and it is our job anyway.
  218  *
  219  * XXX we don't check that there is memory for our bss and page tables
  220  * before using it.
  221  *
  222  * Note: we must be careful to not overwrite an active gdt or idt.  They
  223  * inactive from now until we switch to new ones, since we don't load any
  224  * more segment registers or permit interrupts until after the switch.
  225  */
  226         movl    $R(end),%ecx
  227         movl    $R(edata),%edi
  228         subl    %edi,%ecx
  229         xorl    %eax,%eax
  230         cld
  231         rep
  232         stosb
  233 
  234         call    recover_bootinfo
  235 
  236 /* Get onto a stack that we can trust. */
  237 /*
  238  * XXX this step is delayed in case recover_bootinfo needs to return via
  239  * the old stack, but it need not be, since recover_bootinfo actually
  240  * returns via the old frame.
  241  */
  242         movl    $R(tmpstk),%esp
  243 
  244 #ifdef PC98
  245         /* pc98_machine_type & M_EPSON_PC98 */
  246         testb   $0x02,R(pc98_system_parameter)+220
  247         jz      3f
  248         /* epson_machine_id <= 0x0b */
  249         cmpb    $0x0b,R(pc98_system_parameter)+224
  250         ja      3f
  251 
  252         /* count up memory */
  253         movl    $0x100000,%eax          /* next, talley remaining memory */
  254         movl    $0xFFF-0x100,%ecx
  255 1:      movl    0(%eax),%ebx            /* save location to check */
  256         movl    $0xa55a5aa5,0(%eax)     /* write test pattern */
  257         cmpl    $0xa55a5aa5,0(%eax)     /* does not check yet for rollover */
  258         jne     2f
  259         movl    %ebx,0(%eax)            /* restore memory */
  260         addl    $PAGE_SIZE,%eax
  261         loop    1b
  262 2:      subl    $0x100000,%eax
  263         shrl    $17,%eax
  264         movb    %al,R(pc98_system_parameter)+1
  265 3:
  266 
  267         movw    R(pc98_system_parameter+0x86),%ax
  268         movw    %ax,R(cpu_id)
  269 #endif
  270 
  271         call    identify_cpu
  272         call    create_pagetables
  273 
  274 /*
  275  * If the CPU has support for VME, turn it on.
  276  */ 
  277         testl   $CPUID_VME, R(cpu_feature)
  278         jz      1f
  279         movl    %cr4, %eax
  280         orl     $CR4_VME, %eax
  281         movl    %eax, %cr4
  282 1:
  283 
  284 /* Now enable paging */
  285 #ifdef PAE
  286         movl    R(IdlePDPT), %eax
  287         movl    %eax, %cr3
  288         movl    %cr4, %eax
  289         orl     $CR4_PAE, %eax
  290         movl    %eax, %cr4
  291 #else
  292         movl    R(IdlePTD), %eax
  293         movl    %eax,%cr3               /* load ptd addr into mmu */
  294 #endif
  295         movl    %cr0,%eax               /* get control word */
  296         orl     $CR0_PE|CR0_PG,%eax     /* enable paging */
  297         movl    %eax,%cr0               /* and let's page NOW! */
  298 
  299         pushl   $begin                  /* jump to high virtualized address */
  300         ret
  301 
  302 /* now running relocated at KERNBASE where the system is linked to run */
  303 begin:
  304         /* set up bootstrap stack */
  305         movl    proc0kstack,%eax        /* location of in-kernel stack */
  306                         /* bootstrap stack end location */
  307         leal    (KSTACK_PAGES*PAGE_SIZE-PCB_SIZE)(%eax),%esp
  308 
  309         xorl    %ebp,%ebp               /* mark end of frames */
  310 
  311 #ifdef PAE
  312         movl    IdlePDPT,%esi
  313 #else
  314         movl    IdlePTD,%esi
  315 #endif
  316         movl    %esi,(KSTACK_PAGES*PAGE_SIZE-PCB_SIZE+PCB_CR3)(%eax)
  317 
  318         pushl   physfree                /* value of first for init386(first) */
  319         call    init386                 /* wire 386 chip for unix operation */
  320 
  321         /*
  322          * Clean up the stack in a way that db_numargs() understands, so
  323          * that backtraces in ddb don't underrun the stack.  Traps for
  324          * inaccessible memory are more fatal than usual this early.
  325          */
  326         addl    $4,%esp
  327 
  328         call    mi_startup              /* autoconfiguration, mountroot etc */
  329         /* NOTREACHED */
  330         addl    $0,%esp                 /* for db_numargs() again */
  331 
  332 /*
  333  * Signal trampoline, copied to top of user stack
  334  */
  335 NON_GPROF_ENTRY(sigcode)
  336         calll   *SIGF_HANDLER(%esp)
  337         leal    SIGF_UC(%esp),%eax      /* get ucontext */
  338         pushl   %eax
  339         testl   $PSL_VM,UC_EFLAGS(%eax)
  340         jne     1f
  341         movl    UC_GS(%eax),%gs         /* restore %gs */
  342 1:
  343         movl    $SYS_sigreturn,%eax
  344         pushl   %eax                    /* junk to fake return addr. */
  345         int     $0x80                   /* enter kernel with args */
  346                                         /* on stack */
  347 1:
  348         jmp     1b
  349 
  350 #ifdef COMPAT_FREEBSD4
  351         ALIGN_TEXT
  352 freebsd4_sigcode:
  353         calll   *SIGF_HANDLER(%esp)
  354         leal    SIGF_UC4(%esp),%eax     /* get ucontext */
  355         pushl   %eax
  356         testl   $PSL_VM,UC4_EFLAGS(%eax)
  357         jne     1f
  358         movl    UC4_GS(%eax),%gs        /* restore %gs */
  359 1:
  360         movl    $344,%eax               /* 4.x SYS_sigreturn */
  361         pushl   %eax                    /* junk to fake return addr. */
  362         int     $0x80                   /* enter kernel with args */
  363                                         /* on stack */
  364 1:
  365         jmp     1b
  366 #endif
  367 
  368 #ifdef COMPAT_43
  369         ALIGN_TEXT
  370 osigcode:
  371         call    *SIGF_HANDLER(%esp)     /* call signal handler */
  372         lea     SIGF_SC(%esp),%eax      /* get sigcontext */
  373         pushl   %eax
  374         testl   $PSL_VM,SC_PS(%eax)
  375         jne     9f
  376         movl    SC_GS(%eax),%gs         /* restore %gs */
  377 9:
  378         movl    $103,%eax               /* 3.x SYS_sigreturn */
  379         pushl   %eax                    /* junk to fake return addr. */
  380         int     $0x80                   /* enter kernel with args */
  381 0:      jmp     0b
  382 #endif /* COMPAT_43 */
  383 
  384         ALIGN_TEXT
  385 esigcode:
  386 
  387         .data
  388         .globl  szsigcode
  389 szsigcode:
  390         .long   esigcode-sigcode
  391 #ifdef COMPAT_FREEBSD4
  392         .globl  szfreebsd4_sigcode
  393 szfreebsd4_sigcode:
  394         .long   esigcode-freebsd4_sigcode
  395 #endif
  396 #ifdef COMPAT_43
  397         .globl  szosigcode
  398 szosigcode:
  399         .long   esigcode-osigcode
  400 #endif
  401         .text
  402 
  403 /**********************************************************************
  404  *
  405  * Recover the bootinfo passed to us from the boot program
  406  *
  407  */
  408 recover_bootinfo:
  409         /*
  410          * This code is called in different ways depending on what loaded
  411          * and started the kernel.  This is used to detect how we get the
  412          * arguments from the other code and what we do with them.
  413          *
  414          * Old disk boot blocks:
  415          *      (*btext)(howto, bootdev, cyloffset, esym);
  416          *      [return address == 0, and can NOT be returned to]
  417          *      [cyloffset was not supported by the FreeBSD boot code
  418          *       and always passed in as 0]
  419          *      [esym is also known as total in the boot code, and
  420          *       was never properly supported by the FreeBSD boot code]
  421          *
  422          * Old diskless netboot code:
  423          *      (*btext)(0,0,0,0,&nfsdiskless,0,0,0);
  424          *      [return address != 0, and can NOT be returned to]
  425          *      If we are being booted by this code it will NOT work,
  426          *      so we are just going to halt if we find this case.
  427          *
  428          * New uniform boot code:
  429          *      (*btext)(howto, bootdev, 0, 0, 0, &bootinfo)
  430          *      [return address != 0, and can be returned to]
  431          *
  432          * There may seem to be a lot of wasted arguments in here, but
  433          * that is so the newer boot code can still load very old kernels
  434          * and old boot code can load new kernels.
  435          */
  436 
  437         /*
  438          * The old style disk boot blocks fake a frame on the stack and
  439          * did an lret to get here.  The frame on the stack has a return
  440          * address of 0.
  441          */
  442         cmpl    $0,4(%ebp)
  443         je      olddiskboot
  444 
  445         /*
  446          * We have some form of return address, so this is either the
  447          * old diskless netboot code, or the new uniform code.  That can
  448          * be detected by looking at the 5th argument, if it is 0
  449          * we are being booted by the new uniform boot code.
  450          */
  451         cmpl    $0,24(%ebp)
  452         je      newboot
  453 
  454         /*
  455          * Seems we have been loaded by the old diskless boot code, we
  456          * don't stand a chance of running as the diskless structure
  457          * changed considerably between the two, so just halt.
  458          */
  459          hlt
  460 
  461         /*
  462          * We have been loaded by the new uniform boot code.
  463          * Let's check the bootinfo version, and if we do not understand
  464          * it we return to the loader with a status of 1 to indicate this error
  465          */
  466 newboot:
  467         movl    28(%ebp),%ebx           /* &bootinfo.version */
  468         movl    BI_VERSION(%ebx),%eax
  469         cmpl    $1,%eax                 /* We only understand version 1 */
  470         je      1f
  471         movl    $1,%eax                 /* Return status */
  472         leave
  473         /*
  474          * XXX this returns to our caller's caller (as is required) since
  475          * we didn't set up a frame and our caller did.
  476          */
  477         ret
  478 
  479 1:
  480         /*
  481          * If we have a kernelname copy it in
  482          */
  483         movl    BI_KERNELNAME(%ebx),%esi
  484         cmpl    $0,%esi
  485         je      2f                      /* No kernelname */
  486         movl    $MAXPATHLEN,%ecx        /* Brute force!!! */
  487         movl    $R(kernelname),%edi
  488         cmpb    $'/',(%esi)             /* Make sure it starts with a slash */
  489         je      1f
  490         movb    $'/',(%edi)
  491         incl    %edi
  492         decl    %ecx
  493 1:
  494         cld
  495         rep
  496         movsb
  497 
  498 2:
  499         /*
  500          * Determine the size of the boot loader's copy of the bootinfo
  501          * struct.  This is impossible to do properly because old versions
  502          * of the struct don't contain a size field and there are 2 old
  503          * versions with the same version number.
  504          */
  505         movl    $BI_ENDCOMMON,%ecx      /* prepare for sizeless version */
  506         testl   $RB_BOOTINFO,8(%ebp)    /* bi_size (and bootinfo) valid? */
  507         je      got_bi_size             /* no, sizeless version */
  508         movl    BI_SIZE(%ebx),%ecx
  509 got_bi_size:
  510 
  511         /*
  512          * Copy the common part of the bootinfo struct
  513          */
  514         movl    %ebx,%esi
  515         movl    $R(bootinfo),%edi
  516         cmpl    $BOOTINFO_SIZE,%ecx
  517         jbe     got_common_bi_size
  518         movl    $BOOTINFO_SIZE,%ecx
  519 got_common_bi_size:
  520         cld
  521         rep
  522         movsb
  523 
  524 #ifdef NFS_ROOT
  525 #ifndef BOOTP_NFSV3
  526         /*
  527          * If we have a nfs_diskless structure copy it in
  528          */
  529         movl    BI_NFS_DISKLESS(%ebx),%esi
  530         cmpl    $0,%esi
  531         je      olddiskboot
  532         movl    $R(nfs_diskless),%edi
  533         movl    $NFSDISKLESS_SIZE,%ecx
  534         cld
  535         rep
  536         movsb
  537         movl    $R(nfs_diskless_valid),%edi
  538         movl    $1,(%edi)
  539 #endif
  540 #endif
  541 
  542         /*
  543          * The old style disk boot.
  544          *      (*btext)(howto, bootdev, cyloffset, esym);
  545          * Note that the newer boot code just falls into here to pick
  546          * up howto and bootdev, cyloffset and esym are no longer used
  547          */
  548 olddiskboot:
  549         movl    8(%ebp),%eax
  550         movl    %eax,R(boothowto)
  551         movl    12(%ebp),%eax
  552         movl    %eax,R(bootdev)
  553 
  554         ret
  555 
  556 
  557 /**********************************************************************
  558  *
  559  * Identify the CPU and initialize anything special about it
  560  *
  561  */
  562 identify_cpu:
  563 
  564         /* Try to toggle alignment check flag; does not exist on 386. */
  565         pushfl
  566         popl    %eax
  567         movl    %eax,%ecx
  568         orl     $PSL_AC,%eax
  569         pushl   %eax
  570         popfl
  571         pushfl
  572         popl    %eax
  573         xorl    %ecx,%eax
  574         andl    $PSL_AC,%eax
  575         pushl   %ecx
  576         popfl
  577 
  578         testl   %eax,%eax
  579         jnz     try486
  580 
  581         /* NexGen CPU does not have aligment check flag. */
  582         pushfl
  583         movl    $0x5555, %eax
  584         xorl    %edx, %edx
  585         movl    $2, %ecx
  586         clc
  587         divl    %ecx
  588         jz      trynexgen
  589         popfl
  590         movl    $CPU_386,R(cpu)
  591         jmp     3f
  592 
  593 trynexgen:
  594         popfl
  595         movl    $CPU_NX586,R(cpu)
  596         movl    $0x4778654e,R(cpu_vendor)       # store vendor string
  597         movl    $0x72446e65,R(cpu_vendor+4)
  598         movl    $0x6e657669,R(cpu_vendor+8)
  599         movl    $0,R(cpu_vendor+12)
  600         jmp     3f
  601 
  602 try486: /* Try to toggle identification flag; does not exist on early 486s. */
  603         pushfl
  604         popl    %eax
  605         movl    %eax,%ecx
  606         xorl    $PSL_ID,%eax
  607         pushl   %eax
  608         popfl
  609         pushfl
  610         popl    %eax
  611         xorl    %ecx,%eax
  612         andl    $PSL_ID,%eax
  613         pushl   %ecx
  614         popfl
  615 
  616         testl   %eax,%eax
  617         jnz     trycpuid
  618         movl    $CPU_486,R(cpu)
  619 
  620         /*
  621          * Check Cyrix CPU
  622          * Cyrix CPUs do not change the undefined flags following
  623          * execution of the divide instruction which divides 5 by 2.
  624          *
  625          * Note: CPUID is enabled on M2, so it passes another way.
  626          */
  627         pushfl
  628         movl    $0x5555, %eax
  629         xorl    %edx, %edx
  630         movl    $2, %ecx
  631         clc
  632         divl    %ecx
  633         jnc     trycyrix
  634         popfl
  635         jmp     3f              /* You may use Intel CPU. */
  636 
  637 trycyrix:
  638         popfl
  639         /*
  640          * IBM Bluelighting CPU also doesn't change the undefined flags.
  641          * Because IBM doesn't disclose the information for Bluelighting
  642          * CPU, we couldn't distinguish it from Cyrix's (including IBM
  643          * brand of Cyrix CPUs).
  644          */
  645         movl    $0x69727943,R(cpu_vendor)       # store vendor string
  646         movl    $0x736e4978,R(cpu_vendor+4)
  647         movl    $0x64616574,R(cpu_vendor+8)
  648         jmp     3f
  649 
  650 trycpuid:       /* Use the `cpuid' instruction. */
  651         xorl    %eax,%eax
  652         cpuid                                   # cpuid 0
  653         movl    %eax,R(cpu_high)                # highest capability
  654         movl    %ebx,R(cpu_vendor)              # store vendor string
  655         movl    %edx,R(cpu_vendor+4)
  656         movl    %ecx,R(cpu_vendor+8)
  657         movb    $0,R(cpu_vendor+12)
  658 
  659         movl    $1,%eax
  660         cpuid                                   # cpuid 1
  661         movl    %eax,R(cpu_id)                  # store cpu_id
  662         movl    %ebx,R(cpu_procinfo)            # store cpu_procinfo
  663         movl    %edx,R(cpu_feature)             # store cpu_feature
  664         movl    %ecx,R(cpu_feature2)            # store cpu_feature2
  665         rorl    $8,%eax                         # extract family type
  666         andl    $15,%eax
  667         cmpl    $5,%eax
  668         jae     1f
  669 
  670         /* less than Pentium; must be 486 */
  671         movl    $CPU_486,R(cpu)
  672         jmp     3f
  673 1:
  674         /* a Pentium? */
  675         cmpl    $5,%eax
  676         jne     2f
  677         movl    $CPU_586,R(cpu)
  678         jmp     3f
  679 2:
  680         /* Greater than Pentium...call it a Pentium Pro */
  681         movl    $CPU_686,R(cpu)
  682 3:
  683         ret
  684 
  685 
  686 /**********************************************************************
  687  *
  688  * Create the first page directory and its page tables.
  689  *
  690  */
  691 
  692 create_pagetables:
  693 
  694 /* Find end of kernel image (rounded up to a page boundary). */
  695         movl    $R(_end),%esi
  696 
  697 /* Include symbols, if any. */
  698         movl    R(bootinfo+BI_ESYMTAB),%edi
  699         testl   %edi,%edi
  700         je      over_symalloc
  701         movl    %edi,%esi
  702         movl    $KERNBASE,%edi
  703         addl    %edi,R(bootinfo+BI_SYMTAB)
  704         addl    %edi,R(bootinfo+BI_ESYMTAB)
  705 over_symalloc:
  706 
  707 /* If we are told where the end of the kernel space is, believe it. */
  708         movl    R(bootinfo+BI_KERNEND),%edi
  709         testl   %edi,%edi
  710         je      no_kernend
  711         movl    %edi,%esi
  712 no_kernend:
  713 
  714         addl    $PDRMASK,%esi           /* Play conservative for now, and */
  715         andl    $~PDRMASK,%esi          /*   ... wrap to next 4M. */
  716         movl    %esi,R(KERNend)         /* save end of kernel */
  717         movl    %esi,R(physfree)        /* next free page is at end of kernel */
  718 
  719 /* Allocate Kernel Page Tables */
  720         ALLOCPAGES(NKPT)
  721         movl    %esi,R(KPTphys)
  722 
  723 /* Allocate Page Table Directory */
  724 #ifdef PAE
  725         /* XXX only need 32 bytes (easier for now) */
  726         ALLOCPAGES(1)
  727         movl    %esi,R(IdlePDPT)
  728 #endif
  729         ALLOCPAGES(NPGPTD)
  730         movl    %esi,R(IdlePTD)
  731 
  732 /* Allocate KSTACK */
  733         ALLOCPAGES(KSTACK_PAGES)
  734         movl    %esi,R(p0kpa)
  735         addl    $KERNBASE, %esi
  736         movl    %esi, R(proc0kstack)
  737 
  738         ALLOCPAGES(1)                   /* vm86/bios stack */
  739         movl    %esi,R(vm86phystk)
  740 
  741         ALLOCPAGES(3)                   /* pgtable + ext + IOPAGES */
  742         movl    %esi,R(vm86pa)
  743         addl    $KERNBASE, %esi
  744         movl    %esi, R(vm86paddr)
  745 
  746 /* Map page zero read-write so bios32 calls can use it */
  747         xorl    %eax, %eax
  748         movl    $PG_RW,%edx
  749         movl    $1,%ecx
  750         fillkptphys(%edx)
  751 
  752 /* Map read-only from page 1 to the beginning of the kernel text section */
  753         movl    $PAGE_SIZE, %eax
  754         xorl    %edx,%edx
  755         movl    $R(btext),%ecx
  756         addl    $PAGE_MASK,%ecx
  757         subl    %eax,%ecx
  758         shrl    $PAGE_SHIFT,%ecx
  759         fillkptphys(%edx)
  760 
  761 /*
  762  * Enable PSE and PGE.
  763  */
  764 #ifndef DISABLE_PSE
  765         testl   $CPUID_PSE, R(cpu_feature)
  766         jz      1f
  767         movl    $PG_PS, R(pseflag)
  768         movl    %cr4, %eax
  769         orl     $CR4_PSE, %eax
  770         movl    %eax, %cr4
  771 1:
  772 #endif
  773 #ifndef DISABLE_PG_G
  774         testl   $CPUID_PGE, R(cpu_feature)
  775         jz      2f
  776         movl    $PG_G, R(pgeflag)
  777         movl    %cr4, %eax
  778         orl     $CR4_PGE, %eax
  779         movl    %eax, %cr4
  780 2:
  781 #endif
  782 
  783 /*
  784  * Write page tables for the kernel starting at btext and
  785  * until the end.  Make sure to map read+write.  We do this even
  786  * if we've enabled PSE above, we'll just switch the corresponding kernel
  787  * PDEs before we turn on paging.
  788  *
  789  * XXX: We waste some pages here in the PSE case!  DON'T BLINDLY REMOVE
  790  * THIS!  SMP needs the page table to be there to map the kernel P==V.
  791  */
  792         movl    $R(btext),%eax
  793         addl    $PAGE_MASK, %eax
  794         andl    $~PAGE_MASK, %eax
  795         movl    $PG_RW,%edx
  796         movl    R(KERNend),%ecx
  797         subl    %eax,%ecx
  798         shrl    $PAGE_SHIFT,%ecx
  799         fillkptphys(%edx)
  800 
  801 /* Map page directory. */
  802 #ifdef PAE
  803         movl    R(IdlePDPT), %eax
  804         movl    $1, %ecx
  805         fillkptphys($PG_RW)
  806 #endif
  807 
  808         movl    R(IdlePTD), %eax
  809         movl    $NPGPTD, %ecx
  810         fillkptphys($PG_RW)
  811 
  812 /* Map proc0's KSTACK in the physical way ... */
  813         movl    R(p0kpa), %eax
  814         movl    $(KSTACK_PAGES), %ecx
  815         fillkptphys($PG_RW)
  816 
  817 /* Map ISA hole */
  818         movl    $ISA_HOLE_START, %eax
  819         movl    $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
  820         fillkptphys($PG_RW)
  821 
  822 /* Map space for the vm86 region */
  823         movl    R(vm86phystk), %eax
  824         movl    $4, %ecx
  825         fillkptphys($PG_RW)
  826 
  827 /* Map page 0 into the vm86 page table */
  828         movl    $0, %eax
  829         movl    $0, %ebx
  830         movl    $1, %ecx
  831         fillkpt(R(vm86pa), $PG_RW|PG_U)
  832 
  833 /* ...likewise for the ISA hole */
  834         movl    $ISA_HOLE_START, %eax
  835         movl    $ISA_HOLE_START>>PAGE_SHIFT, %ebx
  836         movl    $ISA_HOLE_LENGTH>>PAGE_SHIFT, %ecx
  837         fillkpt(R(vm86pa), $PG_RW|PG_U)
  838 
  839 /* install a pde for temporary double map of bottom of VA */
  840         movl    R(KPTphys), %eax
  841         xorl    %ebx, %ebx
  842         movl    $NKPT, %ecx
  843         fillkpt(R(IdlePTD), $PG_RW)
  844 
  845 /*
  846  * For the non-PSE case, install PDEs for PTs covering the kernel.
  847  * For the PSE case, do the same, but clobber the ones corresponding
  848  * to the kernel (from btext to KERNend) with 4M ('PS') PDEs immediately
  849  * after.
  850  */
  851         movl    R(KPTphys), %eax
  852         movl    $KPTDI, %ebx
  853         movl    $NKPT, %ecx
  854         fillkpt(R(IdlePTD), $PG_RW)
  855         cmpl    $0,R(pseflag)
  856         je      done_pde
  857 
  858         movl    R(KERNend), %ecx
  859         movl    $KERNLOAD, %eax
  860         subl    %eax, %ecx
  861         shrl    $PDRSHIFT, %ecx
  862         movl    $(KPTDI+(KERNLOAD/(1 << PDRSHIFT))), %ebx
  863         shll    $PDESHIFT, %ebx
  864         addl    R(IdlePTD), %ebx
  865         orl     $(PG_V|PG_RW|PG_PS), %eax
  866 1:      movl    %eax, (%ebx)
  867         addl    $(1 << PDRSHIFT), %eax
  868         addl    $PDESIZE, %ebx
  869         loop    1b
  870 
  871 done_pde:
  872 /* install a pde recursively mapping page directory as a page table */
  873         movl    R(IdlePTD), %eax
  874         movl    $PTDPTDI, %ebx
  875         movl    $NPGPTD,%ecx
  876         fillkpt(R(IdlePTD), $PG_RW)
  877 
  878 #ifdef PAE
  879         movl    R(IdlePTD), %eax
  880         xorl    %ebx, %ebx
  881         movl    $NPGPTD, %ecx
  882         fillkpt(R(IdlePDPT), $0x0)
  883 #endif
  884 
  885         ret

Cache object: 19e456ab4ce6a5906d0bc4eac40576f6


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