The Design and Implementation of the FreeBSD Operating System, Second Edition
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    1 /*-
    2  * Copyright (c) 1993 The Regents of the University of California.
    3  * All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 4. Neither the name of the University nor the names of its contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  *
   29  * $FreeBSD$
   30  */
   31 
   32 #include "opt_npx.h"
   33 
   34 #include <machine/asmacros.h>
   35 #include <machine/cputypes.h>
   36 #include <machine/intr_machdep.h>
   37 #include <machine/pmap.h>
   38 #include <machine/specialreg.h>
   39 
   40 #include "assym.s"
   41 
   42 #define IDXSHIFT        10
   43 
   44         .data
   45         .globl  bcopy_vector
   46 bcopy_vector:
   47         .long   generic_bcopy
   48         .globl  bzero_vector
   49 bzero_vector:
   50         .long   generic_bzero
   51         .globl  copyin_vector
   52 copyin_vector:
   53         .long   generic_copyin
   54         .globl  copyout_vector
   55 copyout_vector:
   56         .long   generic_copyout
   57 #if defined(I586_CPU) && defined(DEV_NPX)
   58 kernel_fpu_lock:
   59         .byte   0xfe
   60         .space  3
   61 #endif
   62         ALIGN_DATA
   63         .globl  intrcnt, eintrcnt
   64 intrcnt:
   65         .space  INTRCNT_COUNT * 4
   66 eintrcnt:
   67 
   68         .globl  intrnames, eintrnames
   69 intrnames:
   70         .space  INTRCNT_COUNT * (MAXCOMLEN + 1)
   71 eintrnames:
   72 
   73         .text
   74 
   75 /*
   76  * bcopy family
   77  * void bzero(void *buf, u_int len)
   78  */
   79 
   80 ENTRY(bzero)
   81         MEXITCOUNT
   82         jmp     *bzero_vector
   83 
   84 ENTRY(generic_bzero)
   85         pushl   %edi
   86         movl    8(%esp),%edi
   87         movl    12(%esp),%ecx
   88         xorl    %eax,%eax
   89         shrl    $2,%ecx
   90         cld
   91         rep
   92         stosl
   93         movl    12(%esp),%ecx
   94         andl    $3,%ecx
   95         rep
   96         stosb
   97         popl    %edi
   98         ret
   99 
  100 #ifdef I486_CPU
  101 ENTRY(i486_bzero)
  102         movl    4(%esp),%edx
  103         movl    8(%esp),%ecx
  104         xorl    %eax,%eax
  105 /*
  106  * do 64 byte chunks first
  107  *
  108  * XXX this is probably over-unrolled at least for DX2's
  109  */
  110 2:
  111         cmpl    $64,%ecx
  112         jb      3f
  113         movl    %eax,(%edx)
  114         movl    %eax,4(%edx)
  115         movl    %eax,8(%edx)
  116         movl    %eax,12(%edx)
  117         movl    %eax,16(%edx)
  118         movl    %eax,20(%edx)
  119         movl    %eax,24(%edx)
  120         movl    %eax,28(%edx)
  121         movl    %eax,32(%edx)
  122         movl    %eax,36(%edx)
  123         movl    %eax,40(%edx)
  124         movl    %eax,44(%edx)
  125         movl    %eax,48(%edx)
  126         movl    %eax,52(%edx)
  127         movl    %eax,56(%edx)
  128         movl    %eax,60(%edx)
  129         addl    $64,%edx
  130         subl    $64,%ecx
  131         jnz     2b
  132         ret
  133 
  134 /*
  135  * do 16 byte chunks
  136  */
  137         SUPERALIGN_TEXT
  138 3:
  139         cmpl    $16,%ecx
  140         jb      4f
  141         movl    %eax,(%edx)
  142         movl    %eax,4(%edx)
  143         movl    %eax,8(%edx)
  144         movl    %eax,12(%edx)
  145         addl    $16,%edx
  146         subl    $16,%ecx
  147         jnz     3b
  148         ret
  149 
  150 /*
  151  * do 4 byte chunks
  152  */
  153         SUPERALIGN_TEXT
  154 4:
  155         cmpl    $4,%ecx
  156         jb      5f
  157         movl    %eax,(%edx)
  158         addl    $4,%edx
  159         subl    $4,%ecx
  160         jnz     4b
  161         ret
  162 
  163 /*
  164  * do 1 byte chunks
  165  * a jump table seems to be faster than a loop or more range reductions
  166  *
  167  * XXX need a const section for non-text
  168  */
  169         .data
  170 jtab:
  171         .long   do0
  172         .long   do1
  173         .long   do2
  174         .long   do3
  175 
  176         .text
  177         SUPERALIGN_TEXT
  178 5:
  179         jmp     *jtab(,%ecx,4)
  180 
  181         SUPERALIGN_TEXT
  182 do3:
  183         movw    %ax,(%edx)
  184         movb    %al,2(%edx)
  185         ret
  186 
  187         SUPERALIGN_TEXT
  188 do2:
  189         movw    %ax,(%edx)
  190         ret
  191 
  192         SUPERALIGN_TEXT
  193 do1:
  194         movb    %al,(%edx)
  195         ret
  196 
  197         SUPERALIGN_TEXT
  198 do0:
  199         ret
  200 #endif
  201 
  202 #if defined(I586_CPU) && defined(DEV_NPX)
  203 ENTRY(i586_bzero)
  204         movl    4(%esp),%edx
  205         movl    8(%esp),%ecx
  206 
  207         /*
  208          * The FPU register method is twice as fast as the integer register
  209          * method unless the target is in the L1 cache and we pre-allocate a
  210          * cache line for it (then the integer register method is 4-5 times
  211          * faster).  However, we never pre-allocate cache lines, since that
  212          * would make the integer method 25% or more slower for the common
  213          * case when the target isn't in either the L1 cache or the L2 cache.
  214          * Thus we normally use the FPU register method unless the overhead
  215          * would be too large.
  216          */
  217         cmpl    $256,%ecx       /* empirical; clts, fninit, smsw cost a lot */
  218         jb      intreg_i586_bzero
  219 
  220         /*
  221          * The FPU registers may belong to an application or to fastmove()
  222          * or to another invocation of bcopy() or ourself in a higher level
  223          * interrupt or trap handler.  Preserving the registers is
  224          * complicated since we avoid it if possible at all levels.  We
  225          * want to localize the complications even when that increases them.
  226          * Here the extra work involves preserving CR0_TS in TS.
  227          * `fpcurthread != NULL' is supposed to be the condition that all the
  228          * FPU resources belong to an application, but fpcurthread and CR0_TS
  229          * aren't set atomically enough for this condition to work in
  230          * interrupt handlers.
  231          *
  232          * Case 1: FPU registers belong to the application: we must preserve
  233          * the registers if we use them, so we only use the FPU register
  234          * method if the target size is large enough to amortize the extra
  235          * overhead for preserving them.  CR0_TS must be preserved although
  236          * it is very likely to end up as set.
  237          *
  238          * Case 2: FPU registers belong to fastmove(): fastmove() currently
  239          * makes the registers look like they belong to an application so
  240          * that cpu_switch() and savectx() don't have to know about it, so
  241          * this case reduces to case 1.
  242          *
  243          * Case 3: FPU registers belong to the kernel: don't use the FPU
  244          * register method.  This case is unlikely, and supporting it would
  245          * be more complicated and might take too much stack.
  246          *
  247          * Case 4: FPU registers don't belong to anyone: the FPU registers
  248          * don't need to be preserved, so we always use the FPU register
  249          * method.  CR0_TS must be preserved although it is very likely to
  250          * always end up as clear.
  251          */
  252         cmpl    $0,PCPU(FPCURTHREAD)
  253         je      i586_bz1
  254 
  255         /*
  256          * XXX don't use the FPU for cases 1 and 2, since preemptive
  257          * scheduling of ithreads broke these cases.  Note that we can
  258          * no longer get here from an interrupt handler, since the
  259          * context sitch to the interrupt handler will have saved the
  260          * FPU state.
  261          */
  262         jmp     intreg_i586_bzero
  263 
  264         cmpl    $256+184,%ecx           /* empirical; not quite 2*108 more */
  265         jb      intreg_i586_bzero
  266         sarb    $1,kernel_fpu_lock
  267         jc      intreg_i586_bzero
  268         smsw    %ax
  269         clts
  270         subl    $108,%esp
  271         fnsave  0(%esp)
  272         jmp     i586_bz2
  273 
  274 i586_bz1:
  275         sarb    $1,kernel_fpu_lock
  276         jc      intreg_i586_bzero
  277         smsw    %ax
  278         clts
  279         fninit                          /* XXX should avoid needing this */
  280 i586_bz2:
  281         fldz
  282 
  283         /*
  284          * Align to an 8 byte boundary (misalignment in the main loop would
  285          * cost a factor of >= 2).  Avoid jumps (at little cost if it is
  286          * already aligned) by always zeroing 8 bytes and using the part up
  287          * to the _next_ alignment position.
  288          */
  289         fstl    0(%edx)
  290         addl    %edx,%ecx               /* part of %ecx -= new_%edx - %edx */
  291         addl    $8,%edx
  292         andl    $~7,%edx
  293         subl    %edx,%ecx
  294 
  295         /*
  296          * Similarly align `len' to a multiple of 8.
  297          */
  298         fstl    -8(%edx,%ecx)
  299         decl    %ecx
  300         andl    $~7,%ecx
  301 
  302         /*
  303          * This wouldn't be any faster if it were unrolled, since the loop
  304          * control instructions are much faster than the fstl and/or done
  305          * in parallel with it so their overhead is insignificant.
  306          */
  307 fpureg_i586_bzero_loop:
  308         fstl    0(%edx)
  309         addl    $8,%edx
  310         subl    $8,%ecx
  311         cmpl    $8,%ecx
  312         jae     fpureg_i586_bzero_loop
  313 
  314         cmpl    $0,PCPU(FPCURTHREAD)
  315         je      i586_bz3
  316 
  317         /* XXX check that the condition for cases 1-2 stayed false. */
  318 i586_bzero_oops:
  319         int     $3
  320         jmp     i586_bzero_oops
  321 
  322         frstor  0(%esp)
  323         addl    $108,%esp
  324         lmsw    %ax
  325         movb    $0xfe,kernel_fpu_lock
  326         ret
  327 
  328 i586_bz3:
  329         fstp    %st(0)
  330         lmsw    %ax
  331         movb    $0xfe,kernel_fpu_lock
  332         ret
  333 
  334 intreg_i586_bzero:
  335         /*
  336          * `rep stos' seems to be the best method in practice for small
  337          * counts.  Fancy methods usually take too long to start up due
  338          * to cache and BTB misses.
  339          */
  340         pushl   %edi
  341         movl    %edx,%edi
  342         xorl    %eax,%eax
  343         shrl    $2,%ecx
  344         cld
  345         rep
  346         stosl
  347         movl    12(%esp),%ecx
  348         andl    $3,%ecx
  349         jne     1f
  350         popl    %edi
  351         ret
  352 
  353 1:
  354         rep
  355         stosb
  356         popl    %edi
  357         ret
  358 #endif /* I586_CPU && defined(DEV_NPX) */
  359 
  360 ENTRY(sse2_pagezero)
  361         pushl   %ebx
  362         movl    8(%esp),%ecx
  363         movl    %ecx,%eax
  364         addl    $4096,%eax
  365         xor     %ebx,%ebx
  366 1:
  367         movnti  %ebx,(%ecx)
  368         addl    $4,%ecx
  369         cmpl    %ecx,%eax
  370         jne     1b
  371         sfence
  372         popl    %ebx
  373         ret
  374 
  375 ENTRY(i686_pagezero)
  376         pushl   %edi
  377         pushl   %ebx
  378 
  379         movl    12(%esp), %edi
  380         movl    $1024, %ecx
  381         cld
  382 
  383         ALIGN_TEXT
  384 1:
  385         xorl    %eax, %eax
  386         repe
  387         scasl
  388         jnz     2f
  389 
  390         popl    %ebx
  391         popl    %edi
  392         ret
  393 
  394         ALIGN_TEXT
  395 
  396 2:
  397         incl    %ecx
  398         subl    $4, %edi
  399 
  400         movl    %ecx, %edx
  401         cmpl    $16, %ecx
  402 
  403         jge     3f
  404 
  405         movl    %edi, %ebx
  406         andl    $0x3f, %ebx
  407         shrl    %ebx
  408         shrl    %ebx
  409         movl    $16, %ecx
  410         subl    %ebx, %ecx
  411 
  412 3:
  413         subl    %ecx, %edx
  414         rep
  415         stosl
  416 
  417         movl    %edx, %ecx
  418         testl   %edx, %edx
  419         jnz     1b
  420 
  421         popl    %ebx
  422         popl    %edi
  423         ret
  424 
  425 /* fillw(pat, base, cnt) */
  426 ENTRY(fillw)
  427         pushl   %edi
  428         movl    8(%esp),%eax
  429         movl    12(%esp),%edi
  430         movl    16(%esp),%ecx
  431         cld
  432         rep
  433         stosw
  434         popl    %edi
  435         ret
  436 
  437 ENTRY(bcopyb)
  438         pushl   %esi
  439         pushl   %edi
  440         movl    12(%esp),%esi
  441         movl    16(%esp),%edi
  442         movl    20(%esp),%ecx
  443         movl    %edi,%eax
  444         subl    %esi,%eax
  445         cmpl    %ecx,%eax                       /* overlapping && src < dst? */
  446         jb      1f
  447         cld                                     /* nope, copy forwards */
  448         rep
  449         movsb
  450         popl    %edi
  451         popl    %esi
  452         ret
  453 
  454         ALIGN_TEXT
  455 1:
  456         addl    %ecx,%edi                       /* copy backwards. */
  457         addl    %ecx,%esi
  458         decl    %edi
  459         decl    %esi
  460         std
  461         rep
  462         movsb
  463         popl    %edi
  464         popl    %esi
  465         cld
  466         ret
  467 
  468 ENTRY(bcopy)
  469         MEXITCOUNT
  470         jmp     *bcopy_vector
  471 
  472 /*
  473  * generic_bcopy(src, dst, cnt)
  474  *  ws@tools.de     (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
  475  */
  476 ENTRY(generic_bcopy)
  477         pushl   %esi
  478         pushl   %edi
  479         movl    12(%esp),%esi
  480         movl    16(%esp),%edi
  481         movl    20(%esp),%ecx
  482 
  483         movl    %edi,%eax
  484         subl    %esi,%eax
  485         cmpl    %ecx,%eax                       /* overlapping && src < dst? */
  486         jb      1f
  487 
  488         shrl    $2,%ecx                         /* copy by 32-bit words */
  489         cld                                     /* nope, copy forwards */
  490         rep
  491         movsl
  492         movl    20(%esp),%ecx
  493         andl    $3,%ecx                         /* any bytes left? */
  494         rep
  495         movsb
  496         popl    %edi
  497         popl    %esi
  498         ret
  499 
  500         ALIGN_TEXT
  501 1:
  502         addl    %ecx,%edi                       /* copy backwards */
  503         addl    %ecx,%esi
  504         decl    %edi
  505         decl    %esi
  506         andl    $3,%ecx                         /* any fractional bytes? */
  507         std
  508         rep
  509         movsb
  510         movl    20(%esp),%ecx                   /* copy remainder by 32-bit words */
  511         shrl    $2,%ecx
  512         subl    $3,%esi
  513         subl    $3,%edi
  514         rep
  515         movsl
  516         popl    %edi
  517         popl    %esi
  518         cld
  519         ret
  520 
  521 #if defined(I586_CPU) && defined(DEV_NPX)
  522 ENTRY(i586_bcopy)
  523         pushl   %esi
  524         pushl   %edi
  525         movl    12(%esp),%esi
  526         movl    16(%esp),%edi
  527         movl    20(%esp),%ecx
  528 
  529         movl    %edi,%eax
  530         subl    %esi,%eax
  531         cmpl    %ecx,%eax                       /* overlapping && src < dst? */
  532         jb      1f
  533 
  534         cmpl    $1024,%ecx
  535         jb      small_i586_bcopy
  536 
  537         sarb    $1,kernel_fpu_lock
  538         jc      small_i586_bcopy
  539         cmpl    $0,PCPU(FPCURTHREAD)
  540         je      i586_bc1
  541 
  542         /* XXX turn off handling of cases 1-2, as above. */
  543         movb    $0xfe,kernel_fpu_lock
  544         jmp     small_i586_bcopy
  545 
  546         smsw    %dx
  547         clts
  548         subl    $108,%esp
  549         fnsave  0(%esp)
  550         jmp     4f
  551 
  552 i586_bc1:
  553         smsw    %dx
  554         clts
  555         fninit                          /* XXX should avoid needing this */
  556 
  557         ALIGN_TEXT
  558 4:
  559         pushl   %ecx
  560 #define DCACHE_SIZE     8192
  561         cmpl    $(DCACHE_SIZE-512)/2,%ecx
  562         jbe     2f
  563         movl    $(DCACHE_SIZE-512)/2,%ecx
  564 2:
  565         subl    %ecx,0(%esp)
  566         cmpl    $256,%ecx
  567         jb      5f                      /* XXX should prefetch if %ecx >= 32 */
  568         pushl   %esi
  569         pushl   %ecx
  570         ALIGN_TEXT
  571 3:
  572         movl    0(%esi),%eax
  573         movl    32(%esi),%eax
  574         movl    64(%esi),%eax
  575         movl    96(%esi),%eax
  576         movl    128(%esi),%eax
  577         movl    160(%esi),%eax
  578         movl    192(%esi),%eax
  579         movl    224(%esi),%eax
  580         addl    $256,%esi
  581         subl    $256,%ecx
  582         cmpl    $256,%ecx
  583         jae     3b
  584         popl    %ecx
  585         popl    %esi
  586 5:
  587         ALIGN_TEXT
  588 large_i586_bcopy_loop:
  589         fildq   0(%esi)
  590         fildq   8(%esi)
  591         fildq   16(%esi)
  592         fildq   24(%esi)
  593         fildq   32(%esi)
  594         fildq   40(%esi)
  595         fildq   48(%esi)
  596         fildq   56(%esi)
  597         fistpq  56(%edi)
  598         fistpq  48(%edi)
  599         fistpq  40(%edi)
  600         fistpq  32(%edi)
  601         fistpq  24(%edi)
  602         fistpq  16(%edi)
  603         fistpq  8(%edi)
  604         fistpq  0(%edi)
  605         addl    $64,%esi
  606         addl    $64,%edi
  607         subl    $64,%ecx
  608         cmpl    $64,%ecx
  609         jae     large_i586_bcopy_loop
  610         popl    %eax
  611         addl    %eax,%ecx
  612         cmpl    $64,%ecx
  613         jae     4b
  614 
  615         cmpl    $0,PCPU(FPCURTHREAD)
  616         je      i586_bc2
  617 
  618         /* XXX check that the condition for cases 1-2 stayed false. */
  619 i586_bcopy_oops:
  620         int     $3
  621         jmp     i586_bcopy_oops
  622 
  623         frstor  0(%esp)
  624         addl    $108,%esp
  625 i586_bc2:
  626         lmsw    %dx
  627         movb    $0xfe,kernel_fpu_lock
  628 
  629 /*
  630  * This is a duplicate of the main part of generic_bcopy.  See the comments
  631  * there.  Jumping into generic_bcopy would cost a whole 0-1 cycles and
  632  * would mess up high resolution profiling.
  633  */
  634         ALIGN_TEXT
  635 small_i586_bcopy:
  636         shrl    $2,%ecx
  637         cld
  638         rep
  639         movsl
  640         movl    20(%esp),%ecx
  641         andl    $3,%ecx
  642         rep
  643         movsb
  644         popl    %edi
  645         popl    %esi
  646         ret
  647 
  648         ALIGN_TEXT
  649 1:
  650         addl    %ecx,%edi
  651         addl    %ecx,%esi
  652         decl    %edi
  653         decl    %esi
  654         andl    $3,%ecx
  655         std
  656         rep
  657         movsb
  658         movl    20(%esp),%ecx
  659         shrl    $2,%ecx
  660         subl    $3,%esi
  661         subl    $3,%edi
  662         rep
  663         movsl
  664         popl    %edi
  665         popl    %esi
  666         cld
  667         ret
  668 #endif /* I586_CPU && defined(DEV_NPX) */
  669 
  670 /*
  671  * Note: memcpy does not support overlapping copies
  672  */
  673 ENTRY(memcpy)
  674         pushl   %edi
  675         pushl   %esi
  676         movl    12(%esp),%edi
  677         movl    16(%esp),%esi
  678         movl    20(%esp),%ecx
  679         movl    %edi,%eax
  680         shrl    $2,%ecx                         /* copy by 32-bit words */
  681         cld                                     /* nope, copy forwards */
  682         rep
  683         movsl
  684         movl    20(%esp),%ecx
  685         andl    $3,%ecx                         /* any bytes left? */
  686         rep
  687         movsb
  688         popl    %esi
  689         popl    %edi
  690         ret
  691 
  692 
  693 /*****************************************************************************/
  694 /* copyout and fubyte family                                                 */
  695 /*****************************************************************************/
  696 /*
  697  * Access user memory from inside the kernel. These routines and possibly
  698  * the math- and DOS emulators should be the only places that do this.
  699  *
  700  * We have to access the memory with user's permissions, so use a segment
  701  * selector with RPL 3. For writes to user space we have to additionally
  702  * check the PTE for write permission, because the 386 does not check
  703  * write permissions when we are executing with EPL 0. The 486 does check
  704  * this if the WP bit is set in CR0, so we can use a simpler version here.
  705  *
  706  * These routines set curpcb->onfault for the time they execute. When a
  707  * protection violation occurs inside the functions, the trap handler
  708  * returns to *curpcb->onfault instead of the function.
  709  */
  710 
  711 /*
  712  * copyout(from_kernel, to_user, len)  - MP SAFE
  713  */
  714 ENTRY(copyout)
  715         MEXITCOUNT
  716         jmp     *copyout_vector
  717 
  718 ENTRY(generic_copyout)
  719         movl    PCPU(CURPCB),%eax
  720         movl    $copyout_fault,PCB_ONFAULT(%eax)
  721         pushl   %esi
  722         pushl   %edi
  723         pushl   %ebx
  724         movl    16(%esp),%esi
  725         movl    20(%esp),%edi
  726         movl    24(%esp),%ebx
  727         testl   %ebx,%ebx                       /* anything to do? */
  728         jz      done_copyout
  729 
  730         /*
  731          * Check explicitly for non-user addresses.  If 486 write protection
  732          * is being used, this check is essential because we are in kernel
  733          * mode so the h/w does not provide any protection against writing
  734          * kernel addresses.
  735          */
  736 
  737         /*
  738          * First, prevent address wrapping.
  739          */
  740         movl    %edi,%eax
  741         addl    %ebx,%eax
  742         jc      copyout_fault
  743 /*
  744  * XXX STOP USING VM_MAXUSER_ADDRESS.
  745  * It is an end address, not a max, so every time it is used correctly it
  746  * looks like there is an off by one error, and of course it caused an off
  747  * by one error in several places.
  748  */
  749         cmpl    $VM_MAXUSER_ADDRESS,%eax
  750         ja      copyout_fault
  751 
  752         /* bcopy(%esi, %edi, %ebx) */
  753         movl    %ebx,%ecx
  754 
  755 #if defined(I586_CPU) && defined(DEV_NPX)
  756         ALIGN_TEXT
  757 slow_copyout:
  758 #endif
  759         shrl    $2,%ecx
  760         cld
  761         rep
  762         movsl
  763         movb    %bl,%cl
  764         andb    $3,%cl
  765         rep
  766         movsb
  767 
  768 done_copyout:
  769         popl    %ebx
  770         popl    %edi
  771         popl    %esi
  772         xorl    %eax,%eax
  773         movl    PCPU(CURPCB),%edx
  774         movl    %eax,PCB_ONFAULT(%edx)
  775         ret
  776 
  777         ALIGN_TEXT
  778 copyout_fault:
  779         popl    %ebx
  780         popl    %edi
  781         popl    %esi
  782         movl    PCPU(CURPCB),%edx
  783         movl    $0,PCB_ONFAULT(%edx)
  784         movl    $EFAULT,%eax
  785         ret
  786 
  787 #if defined(I586_CPU) && defined(DEV_NPX)
  788 ENTRY(i586_copyout)
  789         /*
  790          * Duplicated from generic_copyout.  Could be done a bit better.
  791          */
  792         movl    PCPU(CURPCB),%eax
  793         movl    $copyout_fault,PCB_ONFAULT(%eax)
  794         pushl   %esi
  795         pushl   %edi
  796         pushl   %ebx
  797         movl    16(%esp),%esi
  798         movl    20(%esp),%edi
  799         movl    24(%esp),%ebx
  800         testl   %ebx,%ebx                       /* anything to do? */
  801         jz      done_copyout
  802 
  803         /*
  804          * Check explicitly for non-user addresses.  If 486 write protection
  805          * is being used, this check is essential because we are in kernel
  806          * mode so the h/w does not provide any protection against writing
  807          * kernel addresses.
  808          */
  809 
  810         /*
  811          * First, prevent address wrapping.
  812          */
  813         movl    %edi,%eax
  814         addl    %ebx,%eax
  815         jc      copyout_fault
  816 /*
  817  * XXX STOP USING VM_MAXUSER_ADDRESS.
  818  * It is an end address, not a max, so every time it is used correctly it
  819  * looks like there is an off by one error, and of course it caused an off
  820  * by one error in several places.
  821  */
  822         cmpl    $VM_MAXUSER_ADDRESS,%eax
  823         ja      copyout_fault
  824 
  825         /* bcopy(%esi, %edi, %ebx) */
  826 3:
  827         movl    %ebx,%ecx
  828         /*
  829          * End of duplicated code.
  830          */
  831 
  832         cmpl    $1024,%ecx
  833         jb      slow_copyout
  834 
  835         pushl   %ecx
  836         call    fastmove
  837         addl    $4,%esp
  838         jmp     done_copyout
  839 #endif /* I586_CPU && defined(DEV_NPX) */
  840 
  841 /*
  842  * copyin(from_user, to_kernel, len) - MP SAFE
  843  */
  844 ENTRY(copyin)
  845         MEXITCOUNT
  846         jmp     *copyin_vector
  847 
  848 ENTRY(generic_copyin)
  849         movl    PCPU(CURPCB),%eax
  850         movl    $copyin_fault,PCB_ONFAULT(%eax)
  851         pushl   %esi
  852         pushl   %edi
  853         movl    12(%esp),%esi                   /* caddr_t from */
  854         movl    16(%esp),%edi                   /* caddr_t to */
  855         movl    20(%esp),%ecx                   /* size_t  len */
  856 
  857         /*
  858          * make sure address is valid
  859          */
  860         movl    %esi,%edx
  861         addl    %ecx,%edx
  862         jc      copyin_fault
  863         cmpl    $VM_MAXUSER_ADDRESS,%edx
  864         ja      copyin_fault
  865 
  866 #if defined(I586_CPU) && defined(DEV_NPX)
  867         ALIGN_TEXT
  868 slow_copyin:
  869 #endif
  870         movb    %cl,%al
  871         shrl    $2,%ecx                         /* copy longword-wise */
  872         cld
  873         rep
  874         movsl
  875         movb    %al,%cl
  876         andb    $3,%cl                          /* copy remaining bytes */
  877         rep
  878         movsb
  879 
  880 #if defined(I586_CPU) && defined(DEV_NPX)
  881         ALIGN_TEXT
  882 done_copyin:
  883 #endif
  884         popl    %edi
  885         popl    %esi
  886         xorl    %eax,%eax
  887         movl    PCPU(CURPCB),%edx
  888         movl    %eax,PCB_ONFAULT(%edx)
  889         ret
  890 
  891         ALIGN_TEXT
  892 copyin_fault:
  893         popl    %edi
  894         popl    %esi
  895         movl    PCPU(CURPCB),%edx
  896         movl    $0,PCB_ONFAULT(%edx)
  897         movl    $EFAULT,%eax
  898         ret
  899 
  900 #if defined(I586_CPU) && defined(DEV_NPX)
  901 ENTRY(i586_copyin)
  902         /*
  903          * Duplicated from generic_copyin.  Could be done a bit better.
  904          */
  905         movl    PCPU(CURPCB),%eax
  906         movl    $copyin_fault,PCB_ONFAULT(%eax)
  907         pushl   %esi
  908         pushl   %edi
  909         movl    12(%esp),%esi                   /* caddr_t from */
  910         movl    16(%esp),%edi                   /* caddr_t to */
  911         movl    20(%esp),%ecx                   /* size_t  len */
  912 
  913         /*
  914          * make sure address is valid
  915          */
  916         movl    %esi,%edx
  917         addl    %ecx,%edx
  918         jc      copyin_fault
  919         cmpl    $VM_MAXUSER_ADDRESS,%edx
  920         ja      copyin_fault
  921         /*
  922          * End of duplicated code.
  923          */
  924 
  925         cmpl    $1024,%ecx
  926         jb      slow_copyin
  927 
  928         pushl   %ebx                    /* XXX prepare for fastmove_fault */
  929         pushl   %ecx
  930         call    fastmove
  931         addl    $8,%esp
  932         jmp     done_copyin
  933 #endif /* I586_CPU && defined(DEV_NPX) */
  934 
  935 #if defined(I586_CPU) && defined(DEV_NPX)
  936 /* fastmove(src, dst, len)
  937         src in %esi
  938         dst in %edi
  939         len in %ecx             XXX changed to on stack for profiling
  940         uses %eax and %edx for tmp. storage
  941  */
  942 /* XXX use ENTRY() to get profiling.  fastmove() is actually a non-entry. */
  943 ENTRY(fastmove)
  944         pushl   %ebp
  945         movl    %esp,%ebp
  946         subl    $PCB_SAVEFPU_SIZE+3*4,%esp
  947 
  948         movl    8(%ebp),%ecx
  949         cmpl    $63,%ecx
  950         jbe     fastmove_tail
  951 
  952         testl   $7,%esi /* check if src addr is multiple of 8 */
  953         jnz     fastmove_tail
  954 
  955         testl   $7,%edi /* check if dst addr is multiple of 8 */
  956         jnz     fastmove_tail
  957 
  958         /* XXX grab FPU context atomically. */
  959         cli
  960 
  961 /* if (fpcurthread != NULL) { */
  962         cmpl    $0,PCPU(FPCURTHREAD)
  963         je      6f
  964 /*    fnsave(&curpcb->pcb_savefpu); */
  965         movl    PCPU(CURPCB),%eax
  966         fnsave  PCB_SAVEFPU(%eax)
  967 /*   FPCURTHREAD = NULL; */
  968         movl    $0,PCPU(FPCURTHREAD)
  969 /* } */
  970 6:
  971 /* now we own the FPU. */
  972 
  973 /*
  974  * The process' FP state is saved in the pcb, but if we get
  975  * switched, the cpu_switch() will store our FP state in the
  976  * pcb.  It should be possible to avoid all the copying for
  977  * this, e.g., by setting a flag to tell cpu_switch() to
  978  * save the state somewhere else.
  979  */
  980 /* tmp = curpcb->pcb_savefpu; */
  981         movl    %ecx,-12(%ebp)
  982         movl    %esi,-8(%ebp)
  983         movl    %edi,-4(%ebp)
  984         movl    %esp,%edi
  985         movl    PCPU(CURPCB),%esi
  986         addl    $PCB_SAVEFPU,%esi
  987         cld
  988         movl    $PCB_SAVEFPU_SIZE>>2,%ecx
  989         rep
  990         movsl
  991         movl    -12(%ebp),%ecx
  992         movl    -8(%ebp),%esi
  993         movl    -4(%ebp),%edi
  994 /* stop_emulating(); */
  995         clts
  996 /* fpcurthread = curthread; */
  997         movl    PCPU(CURTHREAD),%eax
  998         movl    %eax,PCPU(FPCURTHREAD)
  999         movl    PCPU(CURPCB),%eax
 1000 
 1001         /* XXX end of atomic FPU context grab. */
 1002         sti
 1003 
 1004         movl    $fastmove_fault,PCB_ONFAULT(%eax)
 1005 4:
 1006         movl    %ecx,-12(%ebp)
 1007         cmpl    $1792,%ecx
 1008         jbe     2f
 1009         movl    $1792,%ecx
 1010 2:
 1011         subl    %ecx,-12(%ebp)
 1012         cmpl    $256,%ecx
 1013         jb      5f
 1014         movl    %ecx,-8(%ebp)
 1015         movl    %esi,-4(%ebp)
 1016         ALIGN_TEXT
 1017 3:
 1018         movl    0(%esi),%eax
 1019         movl    32(%esi),%eax
 1020         movl    64(%esi),%eax
 1021         movl    96(%esi),%eax
 1022         movl    128(%esi),%eax
 1023         movl    160(%esi),%eax
 1024         movl    192(%esi),%eax
 1025         movl    224(%esi),%eax
 1026         addl    $256,%esi
 1027         subl    $256,%ecx
 1028         cmpl    $256,%ecx
 1029         jae     3b
 1030         movl    -8(%ebp),%ecx
 1031         movl    -4(%ebp),%esi
 1032 5:
 1033         ALIGN_TEXT
 1034 fastmove_loop:
 1035         fildq   0(%esi)
 1036         fildq   8(%esi)
 1037         fildq   16(%esi)
 1038         fildq   24(%esi)
 1039         fildq   32(%esi)
 1040         fildq   40(%esi)
 1041         fildq   48(%esi)
 1042         fildq   56(%esi)
 1043         fistpq  56(%edi)
 1044         fistpq  48(%edi)
 1045         fistpq  40(%edi)
 1046         fistpq  32(%edi)
 1047         fistpq  24(%edi)
 1048         fistpq  16(%edi)
 1049         fistpq  8(%edi)
 1050         fistpq  0(%edi)
 1051         addl    $-64,%ecx
 1052         addl    $64,%esi
 1053         addl    $64,%edi
 1054         cmpl    $63,%ecx
 1055         ja      fastmove_loop
 1056         movl    -12(%ebp),%eax
 1057         addl    %eax,%ecx
 1058         cmpl    $64,%ecx
 1059         jae     4b
 1060 
 1061         /* XXX ungrab FPU context atomically. */
 1062         cli
 1063 
 1064 /* curpcb->pcb_savefpu = tmp; */
 1065         movl    %ecx,-12(%ebp)
 1066         movl    %esi,-8(%ebp)
 1067         movl    %edi,-4(%ebp)
 1068         movl    PCPU(CURPCB),%edi
 1069         addl    $PCB_SAVEFPU,%edi
 1070         movl    %esp,%esi
 1071         cld
 1072         movl    $PCB_SAVEFPU_SIZE>>2,%ecx
 1073         rep
 1074         movsl
 1075         movl    -12(%ebp),%ecx
 1076         movl    -8(%ebp),%esi
 1077         movl    -4(%ebp),%edi
 1078 
 1079 /* start_emulating(); */
 1080         smsw    %ax
 1081         orb     $CR0_TS,%al
 1082         lmsw    %ax
 1083 /* fpcurthread = NULL; */
 1084         movl    $0,PCPU(FPCURTHREAD)
 1085 
 1086         /* XXX end of atomic FPU context ungrab. */
 1087         sti
 1088 
 1089         ALIGN_TEXT
 1090 fastmove_tail:
 1091         movl    PCPU(CURPCB),%eax
 1092         movl    $fastmove_tail_fault,PCB_ONFAULT(%eax)
 1093 
 1094         movb    %cl,%al
 1095         shrl    $2,%ecx                         /* copy longword-wise */
 1096         cld
 1097         rep
 1098         movsl
 1099         movb    %al,%cl
 1100         andb    $3,%cl                          /* copy remaining bytes */
 1101         rep
 1102         movsb
 1103 
 1104         movl    %ebp,%esp
 1105         popl    %ebp
 1106         ret
 1107 
 1108         ALIGN_TEXT
 1109 fastmove_fault:
 1110         /* XXX ungrab FPU context atomically. */
 1111         cli
 1112 
 1113         movl    PCPU(CURPCB),%edi
 1114         addl    $PCB_SAVEFPU,%edi
 1115         movl    %esp,%esi
 1116         cld
 1117         movl    $PCB_SAVEFPU_SIZE>>2,%ecx
 1118         rep
 1119         movsl
 1120 
 1121         smsw    %ax
 1122         orb     $CR0_TS,%al
 1123         lmsw    %ax
 1124         movl    $0,PCPU(FPCURTHREAD)
 1125 
 1126         /* XXX end of atomic FPU context ungrab. */
 1127         sti
 1128 
 1129 fastmove_tail_fault:
 1130         movl    %ebp,%esp
 1131         popl    %ebp
 1132         addl    $8,%esp
 1133         popl    %ebx
 1134         popl    %edi
 1135         popl    %esi
 1136         movl    PCPU(CURPCB),%edx
 1137         movl    $0,PCB_ONFAULT(%edx)
 1138         movl    $EFAULT,%eax
 1139         ret
 1140 #endif /* I586_CPU && defined(DEV_NPX) */
 1141 
 1142 /*
 1143  * casuptr.  Compare and set user pointer.  Returns -1 or the current value.
 1144  */
 1145 ENTRY(casuptr)
 1146         movl    PCPU(CURPCB),%ecx
 1147         movl    $fusufault,PCB_ONFAULT(%ecx)
 1148         movl    4(%esp),%edx                    /* dst */
 1149         movl    8(%esp),%eax                    /* old */
 1150         movl    12(%esp),%ecx                   /* new */
 1151 
 1152         cmpl    $VM_MAXUSER_ADDRESS-4,%edx      /* verify address is valid */
 1153         ja      fusufault
 1154 
 1155 #ifdef SMP
 1156         lock
 1157 #endif
 1158         cmpxchgl %ecx, (%edx)                   /* Compare and set. */
 1159 
 1160         /*
 1161          * The old value is in %eax.  If the store succeeded it will be the
 1162          * value we expected (old) from before the store, otherwise it will
 1163          * be the current value.
 1164          */
 1165 
 1166         movl    PCPU(CURPCB),%ecx
 1167         movl    $fusufault,PCB_ONFAULT(%ecx)
 1168         movl    $0,PCB_ONFAULT(%ecx)
 1169         ret
 1170 
 1171 /*
 1172  * Fetch (load) a 32-bit word, a 16-bit word, or an 8-bit byte from user
 1173  * memory.  All these functions are MPSAFE.
 1174  */
 1175 
 1176 ALTENTRY(fuword32)
 1177 ENTRY(fuword)
 1178         movl    PCPU(CURPCB),%ecx
 1179         movl    $fusufault,PCB_ONFAULT(%ecx)
 1180         movl    4(%esp),%edx                    /* from */
 1181 
 1182         cmpl    $VM_MAXUSER_ADDRESS-4,%edx      /* verify address is valid */
 1183         ja      fusufault
 1184 
 1185         movl    (%edx),%eax
 1186         movl    $0,PCB_ONFAULT(%ecx)
 1187         ret
 1188 
 1189 /*
 1190  * fuswintr() and suswintr() are specialized variants of fuword16() and
 1191  * suword16(), respectively.  They are called from the profiling code,
 1192  * potentially at interrupt time.  If they fail, that's okay; good things
 1193  * will happen later.  They always fail for now, until the trap code is
 1194  * able to deal with this.
 1195  */
 1196 ALTENTRY(suswintr)
 1197 ENTRY(fuswintr)
 1198         movl    $-1,%eax
 1199         ret
 1200 
 1201 ENTRY(fuword16)
 1202         movl    PCPU(CURPCB),%ecx
 1203         movl    $fusufault,PCB_ONFAULT(%ecx)
 1204         movl    4(%esp),%edx
 1205 
 1206         cmpl    $VM_MAXUSER_ADDRESS-2,%edx
 1207         ja      fusufault
 1208 
 1209         movzwl  (%edx),%eax
 1210         movl    $0,PCB_ONFAULT(%ecx)
 1211         ret
 1212 
 1213 ENTRY(fubyte)
 1214         movl    PCPU(CURPCB),%ecx
 1215         movl    $fusufault,PCB_ONFAULT(%ecx)
 1216         movl    4(%esp),%edx
 1217 
 1218         cmpl    $VM_MAXUSER_ADDRESS-1,%edx
 1219         ja      fusufault
 1220 
 1221         movzbl  (%edx),%eax
 1222         movl    $0,PCB_ONFAULT(%ecx)
 1223         ret
 1224 
 1225         ALIGN_TEXT
 1226 fusufault:
 1227         movl    PCPU(CURPCB),%ecx
 1228         xorl    %eax,%eax
 1229         movl    %eax,PCB_ONFAULT(%ecx)
 1230         decl    %eax
 1231         ret
 1232 
 1233 /*
 1234  * Store a 32-bit word, a 16-bit word, or an 8-bit byte to user memory.
 1235  * All these functions are MPSAFE.
 1236  */
 1237 
 1238 ALTENTRY(suword32)
 1239 ENTRY(suword)
 1240         movl    PCPU(CURPCB),%ecx
 1241         movl    $fusufault,PCB_ONFAULT(%ecx)
 1242         movl    4(%esp),%edx
 1243 
 1244         cmpl    $VM_MAXUSER_ADDRESS-4,%edx      /* verify address validity */
 1245         ja      fusufault
 1246 
 1247         movl    8(%esp),%eax
 1248         movl    %eax,(%edx)
 1249         xorl    %eax,%eax
 1250         movl    PCPU(CURPCB),%ecx
 1251         movl    %eax,PCB_ONFAULT(%ecx)
 1252         ret
 1253 
 1254 ENTRY(suword16)
 1255         movl    PCPU(CURPCB),%ecx
 1256         movl    $fusufault,PCB_ONFAULT(%ecx)
 1257         movl    4(%esp),%edx
 1258 
 1259         cmpl    $VM_MAXUSER_ADDRESS-2,%edx      /* verify address validity */
 1260         ja      fusufault
 1261 
 1262         movw    8(%esp),%ax
 1263         movw    %ax,(%edx)
 1264         xorl    %eax,%eax
 1265         movl    PCPU(CURPCB),%ecx               /* restore trashed register */
 1266         movl    %eax,PCB_ONFAULT(%ecx)
 1267         ret
 1268 
 1269 ENTRY(subyte)
 1270         movl    PCPU(CURPCB),%ecx
 1271         movl    $fusufault,PCB_ONFAULT(%ecx)
 1272         movl    4(%esp),%edx
 1273 
 1274         cmpl    $VM_MAXUSER_ADDRESS-1,%edx      /* verify address validity */
 1275         ja      fusufault
 1276 
 1277         movb    8(%esp),%al
 1278         movb    %al,(%edx)
 1279         xorl    %eax,%eax
 1280         movl    PCPU(CURPCB),%ecx               /* restore trashed register */
 1281         movl    %eax,PCB_ONFAULT(%ecx)
 1282         ret
 1283 
 1284 /*
 1285  * copyinstr(from, to, maxlen, int *lencopied) - MP SAFE
 1286  *
 1287  *      copy a string from from to to, stop when a 0 character is reached.
 1288  *      return ENAMETOOLONG if string is longer than maxlen, and
 1289  *      EFAULT on protection violations. If lencopied is non-zero,
 1290  *      return the actual length in *lencopied.
 1291  */
 1292 ENTRY(copyinstr)
 1293         pushl   %esi
 1294         pushl   %edi
 1295         movl    PCPU(CURPCB),%ecx
 1296         movl    $cpystrflt,PCB_ONFAULT(%ecx)
 1297 
 1298         movl    12(%esp),%esi                   /* %esi = from */
 1299         movl    16(%esp),%edi                   /* %edi = to */
 1300         movl    20(%esp),%edx                   /* %edx = maxlen */
 1301 
 1302         movl    $VM_MAXUSER_ADDRESS,%eax
 1303 
 1304         /* make sure 'from' is within bounds */
 1305         subl    %esi,%eax
 1306         jbe     cpystrflt
 1307 
 1308         /* restrict maxlen to <= VM_MAXUSER_ADDRESS-from */
 1309         cmpl    %edx,%eax
 1310         jae     1f
 1311         movl    %eax,%edx
 1312         movl    %eax,20(%esp)
 1313 1:
 1314         incl    %edx
 1315         cld
 1316 
 1317 2:
 1318         decl    %edx
 1319         jz      3f
 1320 
 1321         lodsb
 1322         stosb
 1323         orb     %al,%al
 1324         jnz     2b
 1325 
 1326         /* Success -- 0 byte reached */
 1327         decl    %edx
 1328         xorl    %eax,%eax
 1329         jmp     cpystrflt_x
 1330 3:
 1331         /* edx is zero - return ENAMETOOLONG or EFAULT */
 1332         cmpl    $VM_MAXUSER_ADDRESS,%esi
 1333         jae     cpystrflt
 1334 4:
 1335         movl    $ENAMETOOLONG,%eax
 1336         jmp     cpystrflt_x
 1337 
 1338 cpystrflt:
 1339         movl    $EFAULT,%eax
 1340 
 1341 cpystrflt_x:
 1342         /* set *lencopied and return %eax */
 1343         movl    PCPU(CURPCB),%ecx
 1344         movl    $0,PCB_ONFAULT(%ecx)
 1345         movl    20(%esp),%ecx
 1346         subl    %edx,%ecx
 1347         movl    24(%esp),%edx
 1348         testl   %edx,%edx
 1349         jz      1f
 1350         movl    %ecx,(%edx)
 1351 1:
 1352         popl    %edi
 1353         popl    %esi
 1354         ret
 1355 
 1356 
 1357 /*
 1358  * copystr(from, to, maxlen, int *lencopied) - MP SAFE
 1359  */
 1360 ENTRY(copystr)
 1361         pushl   %esi
 1362         pushl   %edi
 1363 
 1364         movl    12(%esp),%esi                   /* %esi = from */
 1365         movl    16(%esp),%edi                   /* %edi = to */
 1366         movl    20(%esp),%edx                   /* %edx = maxlen */
 1367         incl    %edx
 1368         cld
 1369 1:
 1370         decl    %edx
 1371         jz      4f
 1372         lodsb
 1373         stosb
 1374         orb     %al,%al
 1375         jnz     1b
 1376 
 1377         /* Success -- 0 byte reached */
 1378         decl    %edx
 1379         xorl    %eax,%eax
 1380         jmp     6f
 1381 4:
 1382         /* edx is zero -- return ENAMETOOLONG */
 1383         movl    $ENAMETOOLONG,%eax
 1384 
 1385 6:
 1386         /* set *lencopied and return %eax */
 1387         movl    20(%esp),%ecx
 1388         subl    %edx,%ecx
 1389         movl    24(%esp),%edx
 1390         testl   %edx,%edx
 1391         jz      7f
 1392         movl    %ecx,(%edx)
 1393 7:
 1394         popl    %edi
 1395         popl    %esi
 1396         ret
 1397 
 1398 ENTRY(bcmp)
 1399         pushl   %edi
 1400         pushl   %esi
 1401         movl    12(%esp),%edi
 1402         movl    16(%esp),%esi
 1403         movl    20(%esp),%edx
 1404 
 1405         movl    %edx,%ecx
 1406         shrl    $2,%ecx
 1407         cld                                     /* compare forwards */
 1408         repe
 1409         cmpsl
 1410         jne     1f
 1411 
 1412         movl    %edx,%ecx
 1413         andl    $3,%ecx
 1414         repe
 1415         cmpsb
 1416 1:
 1417         setne   %al
 1418         movsbl  %al,%eax
 1419         popl    %esi
 1420         popl    %edi
 1421         ret
 1422 
 1423 
 1424 /*
 1425  * Handling of special 386 registers and descriptor tables etc
 1426  */
 1427 /* void lgdt(struct region_descriptor *rdp); */
 1428 ENTRY(lgdt)
 1429         /* reload the descriptor table */
 1430         movl    4(%esp),%eax
 1431         lgdt    (%eax)
 1432 
 1433         /* flush the prefetch q */
 1434         jmp     1f
 1435         nop
 1436 1:
 1437         /* reload "stale" selectors */
 1438         movl    $KDSEL,%eax
 1439         movl    %eax,%ds
 1440         movl    %eax,%es
 1441         movl    %eax,%gs
 1442         movl    %eax,%ss
 1443         movl    $KPSEL,%eax
 1444         movl    %eax,%fs
 1445 
 1446         /* reload code selector by turning return into intersegmental return */
 1447         movl    (%esp),%eax
 1448         pushl   %eax
 1449         movl    $KCSEL,4(%esp)
 1450         MEXITCOUNT
 1451         lret
 1452 
 1453 /* ssdtosd(*ssdp,*sdp) */
 1454 ENTRY(ssdtosd)
 1455         pushl   %ebx
 1456         movl    8(%esp),%ecx
 1457         movl    8(%ecx),%ebx
 1458         shll    $16,%ebx
 1459         movl    (%ecx),%edx
 1460         roll    $16,%edx
 1461         movb    %dh,%bl
 1462         movb    %dl,%bh
 1463         rorl    $8,%ebx
 1464         movl    4(%ecx),%eax
 1465         movw    %ax,%dx
 1466         andl    $0xf0000,%eax
 1467         orl     %eax,%ebx
 1468         movl    12(%esp),%ecx
 1469         movl    %edx,(%ecx)
 1470         movl    %ebx,4(%ecx)
 1471         popl    %ebx
 1472         ret
 1473 
 1474 /* void reset_dbregs() */
 1475 ENTRY(reset_dbregs)
 1476         movl    $0,%eax
 1477         movl    %eax,%dr7     /* disable all breapoints first */
 1478         movl    %eax,%dr0
 1479         movl    %eax,%dr1
 1480         movl    %eax,%dr2
 1481         movl    %eax,%dr3
 1482         movl    %eax,%dr6
 1483         ret
 1484 
 1485 /*****************************************************************************/
 1486 /* setjump, longjump                                                         */
 1487 /*****************************************************************************/
 1488 
 1489 ENTRY(setjmp)
 1490         movl    4(%esp),%eax
 1491         movl    %ebx,(%eax)                     /* save ebx */
 1492         movl    %esp,4(%eax)                    /* save esp */
 1493         movl    %ebp,8(%eax)                    /* save ebp */
 1494         movl    %esi,12(%eax)                   /* save esi */
 1495         movl    %edi,16(%eax)                   /* save edi */
 1496         movl    (%esp),%edx                     /* get rta */
 1497         movl    %edx,20(%eax)                   /* save eip */
 1498         xorl    %eax,%eax                       /* return(0); */
 1499         ret
 1500 
 1501 ENTRY(longjmp)
 1502         movl    4(%esp),%eax
 1503         movl    (%eax),%ebx                     /* restore ebx */
 1504         movl    4(%eax),%esp                    /* restore esp */
 1505         movl    8(%eax),%ebp                    /* restore ebp */
 1506         movl    12(%eax),%esi                   /* restore esi */
 1507         movl    16(%eax),%edi                   /* restore edi */
 1508         movl    20(%eax),%edx                   /* get rta */
 1509         movl    %edx,(%esp)                     /* put in return frame */
 1510         xorl    %eax,%eax                       /* return(1); */
 1511         incl    %eax
 1512         ret
 1513 
 1514 /*
 1515  * Support for BB-profiling (gcc -a).  The kernbb program will extract
 1516  * the data from the kernel.
 1517  */
 1518 
 1519         .data
 1520         ALIGN_DATA
 1521         .globl bbhead
 1522 bbhead:
 1523         .long 0
 1524 
 1525         .text
 1526 NON_GPROF_ENTRY(__bb_init_func)
 1527         movl    4(%esp),%eax
 1528         movl    $1,(%eax)
 1529         movl    bbhead,%edx
 1530         movl    %edx,16(%eax)
 1531         movl    %eax,bbhead
 1532         NON_GPROF_RET

Cache object: d1b8a437ad836fec31b16e860c9d1cb7


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