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/amd64/amd64/support.S

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    1 /*-
    2  * Copyright (c) 2003 Peter Wemm.
    3  * Copyright (c) 1993 The Regents of the University of California.
    4  * All rights reserved.
    5  *
    6  * Redistribution and use in source and binary forms, with or without
    7  * modification, are permitted provided that the following conditions
    8  * are met:
    9  * 1. Redistributions of source code must retain the above copyright
   10  *    notice, this list of conditions and the following disclaimer.
   11  * 2. Redistributions in binary form must reproduce the above copyright
   12  *    notice, this list of conditions and the following disclaimer in the
   13  *    documentation and/or other materials provided with the distribution.
   14  * 4. Neither the name of the University nor the names of its contributors
   15  *    may be used to endorse or promote products derived from this software
   16  *    without specific prior written permission.
   17  *
   18  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   28  * SUCH DAMAGE.
   29  *
   30  * $FreeBSD: stable/11/sys/amd64/amd64/support.S 338427 2018-09-02 10:51:31Z kib $
   31  */
   32 
   33 #include "opt_ddb.h"
   34 
   35 #include <machine/asmacros.h>
   36 #include <machine/specialreg.h>
   37 #include <machine/pmap.h>
   38 
   39 #include "assym.s"
   40 
   41         .text
   42 
   43 /*
   44  * bcopy family
   45  * void bzero(void *buf, u_int len)
   46  */
   47 
   48 /* done */
   49 ENTRY(bzero)
   50         PUSH_FRAME_POINTER
   51         movq    %rsi,%rcx
   52         xorl    %eax,%eax
   53         shrq    $3,%rcx
   54         rep
   55         stosq
   56         movq    %rsi,%rcx
   57         andq    $7,%rcx
   58         rep
   59         stosb
   60         POP_FRAME_POINTER
   61         ret
   62 END(bzero)
   63 
   64 /* Address: %rdi */
   65 ENTRY(pagezero)
   66         PUSH_FRAME_POINTER
   67         movq    $PAGE_SIZE/8,%rcx
   68         xorl    %eax,%eax
   69         rep
   70         stosq
   71         POP_FRAME_POINTER
   72         ret
   73 END(pagezero)
   74 
   75 ENTRY(bcmp)
   76         PUSH_FRAME_POINTER
   77         movq    %rdx,%rcx
   78         shrq    $3,%rcx
   79         repe
   80         cmpsq
   81         jne     1f
   82 
   83         movq    %rdx,%rcx
   84         andq    $7,%rcx
   85         repe
   86         cmpsb
   87 1:
   88         setne   %al
   89         movsbl  %al,%eax
   90         POP_FRAME_POINTER
   91         ret
   92 END(bcmp)
   93 
   94 /*
   95  * bcopy(src, dst, cnt)
   96  *       rdi, rsi, rdx
   97  *  ws@tools.de     (Wolfgang Solfrank, TooLs GmbH) +49-228-985800
   98  */
   99 ENTRY(bcopy)
  100         PUSH_FRAME_POINTER
  101         xchgq   %rsi,%rdi
  102         movq    %rdx,%rcx
  103 
  104         movq    %rdi,%rax
  105         subq    %rsi,%rax
  106         cmpq    %rcx,%rax                       /* overlapping && src < dst? */
  107         jb      1f
  108 
  109         shrq    $3,%rcx                         /* copy by 64-bit words */
  110         rep
  111         movsq
  112         movq    %rdx,%rcx
  113         andq    $7,%rcx                         /* any bytes left? */
  114         rep
  115         movsb
  116         POP_FRAME_POINTER
  117         ret
  118 
  119         /* ALIGN_TEXT */
  120 1:
  121         addq    %rcx,%rdi                       /* copy backwards */
  122         addq    %rcx,%rsi
  123         decq    %rdi
  124         decq    %rsi
  125         andq    $7,%rcx                         /* any fractional bytes? */
  126         std
  127         rep
  128         movsb
  129         movq    %rdx,%rcx                       /* copy remainder by 32-bit words */
  130         shrq    $3,%rcx
  131         subq    $7,%rsi
  132         subq    $7,%rdi
  133         rep
  134         movsq
  135         cld
  136         POP_FRAME_POINTER
  137         ret
  138 END(bcopy)
  139 
  140 /*
  141  * Note: memcpy does not support overlapping copies
  142  */
  143 ENTRY(memcpy)
  144         PUSH_FRAME_POINTER
  145         movq    %rdi,%rax
  146         movq    %rdx,%rcx
  147         shrq    $3,%rcx                         /* copy by 64-bit words */
  148         rep
  149         movsq
  150         movq    %rdx,%rcx
  151         andq    $7,%rcx                         /* any bytes left? */
  152         rep
  153         movsb
  154         POP_FRAME_POINTER
  155         ret
  156 END(memcpy)
  157 
  158 /*
  159  * pagecopy(%rdi=from, %rsi=to)
  160  */
  161 ENTRY(pagecopy)
  162         PUSH_FRAME_POINTER
  163         movq    $-PAGE_SIZE,%rax
  164         movq    %rax,%rdx
  165         subq    %rax,%rdi
  166         subq    %rax,%rsi
  167 1:
  168         prefetchnta (%rdi,%rax)
  169         addq    $64,%rax
  170         jne     1b
  171 2:
  172         movq    (%rdi,%rdx),%rax
  173         movnti  %rax,(%rsi,%rdx)
  174         movq    8(%rdi,%rdx),%rax
  175         movnti  %rax,8(%rsi,%rdx)
  176         movq    16(%rdi,%rdx),%rax
  177         movnti  %rax,16(%rsi,%rdx)
  178         movq    24(%rdi,%rdx),%rax
  179         movnti  %rax,24(%rsi,%rdx)
  180         addq    $32,%rdx
  181         jne     2b
  182         sfence
  183         POP_FRAME_POINTER
  184         ret
  185 END(pagecopy)
  186 
  187 /* fillw(pat, base, cnt) */
  188 /*       %rdi,%rsi, %rdx */
  189 ENTRY(fillw)
  190         PUSH_FRAME_POINTER
  191         movq    %rdi,%rax
  192         movq    %rsi,%rdi
  193         movq    %rdx,%rcx
  194         rep
  195         stosw
  196         POP_FRAME_POINTER
  197         ret
  198 END(fillw)
  199 
  200 /*****************************************************************************/
  201 /* copyout and fubyte family                                                 */
  202 /*****************************************************************************/
  203 /*
  204  * Access user memory from inside the kernel. These routines should be
  205  * the only places that do this.
  206  *
  207  * These routines set curpcb->pcb_onfault for the time they execute. When a
  208  * protection violation occurs inside the functions, the trap handler
  209  * returns to *curpcb->pcb_onfault instead of the function.
  210  */
  211 
  212 /*
  213  * copyout(from_kernel, to_user, len)
  214  *         %rdi,        %rsi,    %rdx
  215  */
  216 ENTRY(copyout)
  217         PUSH_FRAME_POINTER
  218         movq    PCPU(CURPCB),%rax
  219         movq    $copyout_fault,PCB_ONFAULT(%rax)
  220         testq   %rdx,%rdx                       /* anything to do? */
  221         jz      done_copyout
  222 
  223         /*
  224          * Check explicitly for non-user addresses.  This check is essential
  225          * because it prevents usermode from writing into the kernel.  We do
  226          * not verify anywhere else that the user did not specify a rogue
  227          * address.
  228          */
  229         /*
  230          * First, prevent address wrapping.
  231          */
  232         movq    %rsi,%rax
  233         addq    %rdx,%rax
  234         jc      copyout_fault
  235 /*
  236  * XXX STOP USING VM_MAXUSER_ADDRESS.
  237  * It is an end address, not a max, so every time it is used correctly it
  238  * looks like there is an off by one error, and of course it caused an off
  239  * by one error in several places.
  240  */
  241         movq    $VM_MAXUSER_ADDRESS,%rcx
  242         cmpq    %rcx,%rax
  243         ja      copyout_fault
  244 
  245         xchgq   %rdi,%rsi
  246         /* bcopy(%rsi, %rdi, %rdx) */
  247         movq    %rdx,%rcx
  248 
  249         shrq    $3,%rcx
  250         rep
  251         movsq
  252         movb    %dl,%cl
  253         andb    $7,%cl
  254         rep
  255         movsb
  256 
  257 done_copyout:
  258         xorl    %eax,%eax
  259         movq    PCPU(CURPCB),%rdx
  260         movq    %rax,PCB_ONFAULT(%rdx)
  261         POP_FRAME_POINTER
  262         ret
  263 
  264         ALIGN_TEXT
  265 copyout_fault:
  266         movq    PCPU(CURPCB),%rdx
  267         movq    $0,PCB_ONFAULT(%rdx)
  268         movq    $EFAULT,%rax
  269         POP_FRAME_POINTER
  270         ret
  271 END(copyout)
  272 
  273 /*
  274  * copyin(from_user, to_kernel, len)
  275  *        %rdi,      %rsi,      %rdx
  276  */
  277 ENTRY(copyin)
  278         PUSH_FRAME_POINTER
  279         movq    PCPU(CURPCB),%rax
  280         movq    $copyin_fault,PCB_ONFAULT(%rax)
  281         testq   %rdx,%rdx                       /* anything to do? */
  282         jz      done_copyin
  283 
  284         /*
  285          * make sure address is valid
  286          */
  287         movq    %rdi,%rax
  288         addq    %rdx,%rax
  289         jc      copyin_fault
  290         movq    $VM_MAXUSER_ADDRESS,%rcx
  291         cmpq    %rcx,%rax
  292         ja      copyin_fault
  293 
  294         xchgq   %rdi,%rsi
  295         movq    %rdx,%rcx
  296         movb    %cl,%al
  297         shrq    $3,%rcx                         /* copy longword-wise */
  298         rep
  299         movsq
  300         movb    %al,%cl
  301         andb    $7,%cl                          /* copy remaining bytes */
  302         rep
  303         movsb
  304 
  305 done_copyin:
  306         xorl    %eax,%eax
  307         movq    PCPU(CURPCB),%rdx
  308         movq    %rax,PCB_ONFAULT(%rdx)
  309         POP_FRAME_POINTER
  310         ret
  311 
  312         ALIGN_TEXT
  313 copyin_fault:
  314         movq    PCPU(CURPCB),%rdx
  315         movq    $0,PCB_ONFAULT(%rdx)
  316         movq    $EFAULT,%rax
  317         POP_FRAME_POINTER
  318         ret
  319 END(copyin)
  320 
  321 /*
  322  * casueword32.  Compare and set user integer.  Returns -1 on fault,
  323  *        0 if access was successful.  Old value is written to *oldp.
  324  *        dst = %rdi, old = %esi, oldp = %rdx, new = %ecx
  325  */
  326 ENTRY(casueword32)
  327         PUSH_FRAME_POINTER
  328         movq    PCPU(CURPCB),%r8
  329         movq    $fusufault,PCB_ONFAULT(%r8)
  330 
  331         movq    $VM_MAXUSER_ADDRESS-4,%rax
  332         cmpq    %rax,%rdi                       /* verify address is valid */
  333         ja      fusufault
  334 
  335         movl    %esi,%eax                       /* old */
  336 #ifdef SMP
  337         lock
  338 #endif
  339         cmpxchgl %ecx,(%rdi)                    /* new = %ecx */
  340 
  341         /*
  342          * The old value is in %eax.  If the store succeeded it will be the
  343          * value we expected (old) from before the store, otherwise it will
  344          * be the current value.  Save %eax into %esi to prepare the return
  345          * value.
  346          */
  347         movl    %eax,%esi
  348         xorl    %eax,%eax
  349         movq    %rax,PCB_ONFAULT(%r8)
  350 
  351         /*
  352          * Access the oldp after the pcb_onfault is cleared, to correctly
  353          * catch corrupted pointer.
  354          */
  355         movl    %esi,(%rdx)                     /* oldp = %rdx */
  356         POP_FRAME_POINTER
  357         ret
  358 END(casueword32)
  359 
  360 /*
  361  * casueword.  Compare and set user long.  Returns -1 on fault,
  362  *        0 if access was successful.  Old value is written to *oldp.
  363  *        dst = %rdi, old = %rsi, oldp = %rdx, new = %rcx
  364  */
  365 ENTRY(casueword)
  366         PUSH_FRAME_POINTER
  367         movq    PCPU(CURPCB),%r8
  368         movq    $fusufault,PCB_ONFAULT(%r8)
  369 
  370         movq    $VM_MAXUSER_ADDRESS-4,%rax
  371         cmpq    %rax,%rdi                       /* verify address is valid */
  372         ja      fusufault
  373 
  374         movq    %rsi,%rax                       /* old */
  375 #ifdef SMP
  376         lock
  377 #endif
  378         cmpxchgq %rcx,(%rdi)                    /* new = %rcx */
  379 
  380         /*
  381          * The old value is in %rax.  If the store succeeded it will be the
  382          * value we expected (old) from before the store, otherwise it will
  383          * be the current value.
  384          */
  385         movq    %rax,%rsi
  386         xorl    %eax,%eax
  387         movq    %rax,PCB_ONFAULT(%r8)
  388         movq    %rsi,(%rdx)
  389         POP_FRAME_POINTER
  390         ret
  391 END(casueword)
  392 
  393 /*
  394  * Fetch (load) a 64-bit word, a 32-bit word, a 16-bit word, or an 8-bit
  395  * byte from user memory.
  396  * addr = %rdi, valp = %rsi
  397  */
  398 
  399 ALTENTRY(fueword64)
  400 ENTRY(fueword)
  401         PUSH_FRAME_POINTER
  402         movq    PCPU(CURPCB),%rcx
  403         movq    $fusufault,PCB_ONFAULT(%rcx)
  404 
  405         movq    $VM_MAXUSER_ADDRESS-8,%rax
  406         cmpq    %rax,%rdi                       /* verify address is valid */
  407         ja      fusufault
  408 
  409         xorl    %eax,%eax
  410         movq    (%rdi),%r11
  411         movq    %rax,PCB_ONFAULT(%rcx)
  412         movq    %r11,(%rsi)
  413         POP_FRAME_POINTER
  414         ret
  415 END(fueword64)
  416 END(fueword)
  417 
  418 ENTRY(fueword32)
  419         PUSH_FRAME_POINTER
  420         movq    PCPU(CURPCB),%rcx
  421         movq    $fusufault,PCB_ONFAULT(%rcx)
  422 
  423         movq    $VM_MAXUSER_ADDRESS-4,%rax
  424         cmpq    %rax,%rdi                       /* verify address is valid */
  425         ja      fusufault
  426 
  427         xorl    %eax,%eax
  428         movl    (%rdi),%r11d
  429         movq    %rax,PCB_ONFAULT(%rcx)
  430         movl    %r11d,(%rsi)
  431         POP_FRAME_POINTER
  432         ret
  433 END(fueword32)
  434 
  435 /*
  436  * fuswintr() and suswintr() are specialized variants of fuword16() and
  437  * suword16(), respectively.  They are called from the profiling code,
  438  * potentially at interrupt time.  If they fail, that's okay; good things
  439  * will happen later.  They always fail for now, until the trap code is
  440  * able to deal with this.
  441  */
  442 ALTENTRY(suswintr)
  443 ENTRY(fuswintr)
  444         movq    $-1,%rax
  445         ret
  446 END(suswintr)
  447 END(fuswintr)
  448 
  449 ENTRY(fuword16)
  450         PUSH_FRAME_POINTER
  451         movq    PCPU(CURPCB),%rcx
  452         movq    $fusufault,PCB_ONFAULT(%rcx)
  453 
  454         movq    $VM_MAXUSER_ADDRESS-2,%rax
  455         cmpq    %rax,%rdi
  456         ja      fusufault
  457 
  458         movzwl  (%rdi),%eax
  459         movq    $0,PCB_ONFAULT(%rcx)
  460         POP_FRAME_POINTER
  461         ret
  462 END(fuword16)
  463 
  464 ENTRY(fubyte)
  465         PUSH_FRAME_POINTER
  466         movq    PCPU(CURPCB),%rcx
  467         movq    $fusufault,PCB_ONFAULT(%rcx)
  468 
  469         movq    $VM_MAXUSER_ADDRESS-1,%rax
  470         cmpq    %rax,%rdi
  471         ja      fusufault
  472 
  473         movzbl  (%rdi),%eax
  474         movq    $0,PCB_ONFAULT(%rcx)
  475         POP_FRAME_POINTER
  476         ret
  477 END(fubyte)
  478 
  479         ALIGN_TEXT
  480 fusufault:
  481         movq    PCPU(CURPCB),%rcx
  482         xorl    %eax,%eax
  483         movq    %rax,PCB_ONFAULT(%rcx)
  484         decq    %rax
  485         POP_FRAME_POINTER
  486         ret
  487 
  488 /*
  489  * Store a 64-bit word, a 32-bit word, a 16-bit word, or an 8-bit byte to
  490  * user memory.
  491  * addr = %rdi, value = %rsi
  492  */
  493 ALTENTRY(suword64)
  494 ENTRY(suword)
  495         PUSH_FRAME_POINTER
  496         movq    PCPU(CURPCB),%rcx
  497         movq    $fusufault,PCB_ONFAULT(%rcx)
  498 
  499         movq    $VM_MAXUSER_ADDRESS-8,%rax
  500         cmpq    %rax,%rdi                       /* verify address validity */
  501         ja      fusufault
  502 
  503         movq    %rsi,(%rdi)
  504         xorl    %eax,%eax
  505         movq    PCPU(CURPCB),%rcx
  506         movq    %rax,PCB_ONFAULT(%rcx)
  507         POP_FRAME_POINTER
  508         ret
  509 END(suword64)
  510 END(suword)
  511 
  512 ENTRY(suword32)
  513         PUSH_FRAME_POINTER
  514         movq    PCPU(CURPCB),%rcx
  515         movq    $fusufault,PCB_ONFAULT(%rcx)
  516 
  517         movq    $VM_MAXUSER_ADDRESS-4,%rax
  518         cmpq    %rax,%rdi                       /* verify address validity */
  519         ja      fusufault
  520 
  521         movl    %esi,(%rdi)
  522         xorl    %eax,%eax
  523         movq    PCPU(CURPCB),%rcx
  524         movq    %rax,PCB_ONFAULT(%rcx)
  525         POP_FRAME_POINTER
  526         ret
  527 END(suword32)
  528 
  529 ENTRY(suword16)
  530         PUSH_FRAME_POINTER
  531         movq    PCPU(CURPCB),%rcx
  532         movq    $fusufault,PCB_ONFAULT(%rcx)
  533 
  534         movq    $VM_MAXUSER_ADDRESS-2,%rax
  535         cmpq    %rax,%rdi                       /* verify address validity */
  536         ja      fusufault
  537 
  538         movw    %si,(%rdi)
  539         xorl    %eax,%eax
  540         movq    PCPU(CURPCB),%rcx               /* restore trashed register */
  541         movq    %rax,PCB_ONFAULT(%rcx)
  542         POP_FRAME_POINTER
  543         ret
  544 END(suword16)
  545 
  546 ENTRY(subyte)
  547         PUSH_FRAME_POINTER
  548         movq    PCPU(CURPCB),%rcx
  549         movq    $fusufault,PCB_ONFAULT(%rcx)
  550 
  551         movq    $VM_MAXUSER_ADDRESS-1,%rax
  552         cmpq    %rax,%rdi                       /* verify address validity */
  553         ja      fusufault
  554 
  555         movl    %esi,%eax
  556         movb    %al,(%rdi)
  557         xorl    %eax,%eax
  558         movq    PCPU(CURPCB),%rcx               /* restore trashed register */
  559         movq    %rax,PCB_ONFAULT(%rcx)
  560         POP_FRAME_POINTER
  561         ret
  562 END(subyte)
  563 
  564 /*
  565  * copyinstr(from, to, maxlen, int *lencopied)
  566  *           %rdi, %rsi, %rdx, %rcx
  567  *
  568  *      copy a string from 'from' to 'to', stop when a 0 character is reached.
  569  *      return ENAMETOOLONG if string is longer than maxlen, and
  570  *      EFAULT on protection violations. If lencopied is non-zero,
  571  *      return the actual length in *lencopied.
  572  */
  573 ENTRY(copyinstr)
  574         PUSH_FRAME_POINTER
  575         movq    %rdx,%r8                        /* %r8 = maxlen */
  576         movq    %rcx,%r9                        /* %r9 = *len */
  577         xchgq   %rdi,%rsi                       /* %rdi = from, %rsi = to */
  578         movq    PCPU(CURPCB),%rcx
  579         movq    $cpystrflt,PCB_ONFAULT(%rcx)
  580 
  581         movq    $VM_MAXUSER_ADDRESS,%rax
  582 
  583         /* make sure 'from' is within bounds */
  584         subq    %rsi,%rax
  585         jbe     cpystrflt
  586 
  587         /* restrict maxlen to <= VM_MAXUSER_ADDRESS-from */
  588         cmpq    %rdx,%rax
  589         jae     1f
  590         movq    %rax,%rdx
  591         movq    %rax,%r8
  592 1:
  593         incq    %rdx
  594 
  595 2:
  596         decq    %rdx
  597         jz      3f
  598 
  599         lodsb
  600         stosb
  601         orb     %al,%al
  602         jnz     2b
  603 
  604         /* Success -- 0 byte reached */
  605         decq    %rdx
  606         xorl    %eax,%eax
  607         jmp     cpystrflt_x
  608 3:
  609         /* rdx is zero - return ENAMETOOLONG or EFAULT */
  610         movq    $VM_MAXUSER_ADDRESS,%rax
  611         cmpq    %rax,%rsi
  612         jae     cpystrflt
  613 4:
  614         movq    $ENAMETOOLONG,%rax
  615         jmp     cpystrflt_x
  616 
  617 cpystrflt:
  618         movq    $EFAULT,%rax
  619 
  620 cpystrflt_x:
  621         /* set *lencopied and return %eax */
  622         movq    PCPU(CURPCB),%rcx
  623         movq    $0,PCB_ONFAULT(%rcx)
  624 
  625         testq   %r9,%r9
  626         jz      1f
  627         subq    %rdx,%r8
  628         movq    %r8,(%r9)
  629 1:
  630         POP_FRAME_POINTER
  631         ret
  632 END(copyinstr)
  633 
  634 /*
  635  * copystr(from, to, maxlen, int *lencopied)
  636  *         %rdi, %rsi, %rdx, %rcx
  637  */
  638 ENTRY(copystr)
  639         PUSH_FRAME_POINTER
  640         movq    %rdx,%r8                        /* %r8 = maxlen */
  641 
  642         xchgq   %rdi,%rsi
  643         incq    %rdx
  644 1:
  645         decq    %rdx
  646         jz      4f
  647         lodsb
  648         stosb
  649         orb     %al,%al
  650         jnz     1b
  651 
  652         /* Success -- 0 byte reached */
  653         decq    %rdx
  654         xorl    %eax,%eax
  655         jmp     6f
  656 4:
  657         /* rdx is zero -- return ENAMETOOLONG */
  658         movq    $ENAMETOOLONG,%rax
  659 
  660 6:
  661 
  662         testq   %rcx,%rcx
  663         jz      7f
  664         /* set *lencopied and return %rax */
  665         subq    %rdx,%r8
  666         movq    %r8,(%rcx)
  667 7:
  668         POP_FRAME_POINTER
  669         ret
  670 END(copystr)
  671 
  672 /*
  673  * Handling of special amd64 registers and descriptor tables etc
  674  */
  675 /* void lgdt(struct region_descriptor *rdp); */
  676 ENTRY(lgdt)
  677         /* reload the descriptor table */
  678         lgdt    (%rdi)
  679 
  680         /* flush the prefetch q */
  681         jmp     1f
  682         nop
  683 1:
  684         movl    $KDSEL,%eax
  685         movl    %eax,%ds
  686         movl    %eax,%es
  687         movl    %eax,%fs        /* Beware, use wrmsr to set 64 bit base */
  688         movl    %eax,%gs
  689         movl    %eax,%ss
  690 
  691         /* reload code selector by turning return into intersegmental return */
  692         popq    %rax
  693         pushq   $KCSEL
  694         pushq   %rax
  695         MEXITCOUNT
  696         lretq
  697 END(lgdt)
  698 
  699 /*****************************************************************************/
  700 /* setjump, longjump                                                         */
  701 /*****************************************************************************/
  702 
  703 ENTRY(setjmp)
  704         movq    %rbx,0(%rdi)                    /* save rbx */
  705         movq    %rsp,8(%rdi)                    /* save rsp */
  706         movq    %rbp,16(%rdi)                   /* save rbp */
  707         movq    %r12,24(%rdi)                   /* save r12 */
  708         movq    %r13,32(%rdi)                   /* save r13 */
  709         movq    %r14,40(%rdi)                   /* save r14 */
  710         movq    %r15,48(%rdi)                   /* save r15 */
  711         movq    0(%rsp),%rdx                    /* get rta */
  712         movq    %rdx,56(%rdi)                   /* save rip */
  713         xorl    %eax,%eax                       /* return(0); */
  714         ret
  715 END(setjmp)
  716 
  717 ENTRY(longjmp)
  718         movq    0(%rdi),%rbx                    /* restore rbx */
  719         movq    8(%rdi),%rsp                    /* restore rsp */
  720         movq    16(%rdi),%rbp                   /* restore rbp */
  721         movq    24(%rdi),%r12                   /* restore r12 */
  722         movq    32(%rdi),%r13                   /* restore r13 */
  723         movq    40(%rdi),%r14                   /* restore r14 */
  724         movq    48(%rdi),%r15                   /* restore r15 */
  725         movq    56(%rdi),%rdx                   /* get rta */
  726         movq    %rdx,0(%rsp)                    /* put in return frame */
  727         xorl    %eax,%eax                       /* return(1); */
  728         incl    %eax
  729         ret
  730 END(longjmp)
  731 
  732 /*
  733  * Support for reading MSRs in the safe manner.
  734  */
  735 ENTRY(rdmsr_safe)
  736 /* int rdmsr_safe(u_int msr, uint64_t *data) */
  737         PUSH_FRAME_POINTER
  738         movq    PCPU(CURPCB),%r8
  739         movq    $msr_onfault,PCB_ONFAULT(%r8)
  740         movl    %edi,%ecx
  741         rdmsr                   /* Read MSR pointed by %ecx. Returns
  742                                    hi byte in edx, lo in %eax */
  743         salq    $32,%rdx        /* sign-shift %rdx left */
  744         movl    %eax,%eax       /* zero-extend %eax -> %rax */
  745         orq     %rdx,%rax
  746         movq    %rax,(%rsi)
  747         xorq    %rax,%rax
  748         movq    %rax,PCB_ONFAULT(%r8)
  749         POP_FRAME_POINTER
  750         ret
  751 
  752 /*
  753  * Support for writing MSRs in the safe manner.
  754  */
  755 ENTRY(wrmsr_safe)
  756 /* int wrmsr_safe(u_int msr, uint64_t data) */
  757         PUSH_FRAME_POINTER
  758         movq    PCPU(CURPCB),%r8
  759         movq    $msr_onfault,PCB_ONFAULT(%r8)
  760         movl    %edi,%ecx
  761         movl    %esi,%eax
  762         sarq    $32,%rsi
  763         movl    %esi,%edx
  764         wrmsr                   /* Write MSR pointed by %ecx. Accepts
  765                                    hi byte in edx, lo in %eax. */
  766         xorq    %rax,%rax
  767         movq    %rax,PCB_ONFAULT(%r8)
  768         POP_FRAME_POINTER
  769         ret
  770 
  771 /*
  772  * MSR operations fault handler
  773  */
  774         ALIGN_TEXT
  775 msr_onfault:
  776         movq    $0,PCB_ONFAULT(%r8)
  777         movl    $EFAULT,%eax
  778         POP_FRAME_POINTER
  779         ret
  780 
  781 /*
  782  * void pmap_pti_pcid_invalidate(uint64_t ucr3, uint64_t kcr3);
  783  * Invalidates address space addressed by ucr3, then returns to kcr3.
  784  * Done in assembler to ensure no other memory accesses happen while
  785  * on ucr3.
  786  */
  787         ALIGN_TEXT
  788 ENTRY(pmap_pti_pcid_invalidate)
  789         pushfq
  790         cli
  791         movq    %rdi,%cr3       /* to user page table */
  792         movq    %rsi,%cr3       /* back to kernel */
  793         popfq
  794         retq
  795 
  796 /*
  797  * void pmap_pti_pcid_invlpg(uint64_t ucr3, uint64_t kcr3, vm_offset_t va);
  798  * Invalidates virtual address va in address space ucr3, then returns to kcr3.
  799  */
  800         ALIGN_TEXT
  801 ENTRY(pmap_pti_pcid_invlpg)
  802         pushfq
  803         cli
  804         movq    %rdi,%cr3       /* to user page table */
  805         invlpg  (%rdx)
  806         movq    %rsi,%cr3       /* back to kernel */
  807         popfq
  808         retq
  809 
  810 /*
  811  * void pmap_pti_pcid_invlrng(uint64_t ucr3, uint64_t kcr3, vm_offset_t sva,
  812  *     vm_offset_t eva);
  813  * Invalidates virtual addresses between sva and eva in address space ucr3,
  814  * then returns to kcr3.
  815  */
  816         ALIGN_TEXT
  817 ENTRY(pmap_pti_pcid_invlrng)
  818         pushfq
  819         cli
  820         movq    %rdi,%cr3       /* to user page table */
  821 1:      invlpg  (%rdx)
  822         addq    $PAGE_SIZE,%rdx
  823         cmpq    %rdx,%rcx
  824         ja      1b
  825         movq    %rsi,%cr3       /* back to kernel */
  826         popfq
  827         retq
  828 
  829         .altmacro
  830         .macro  ibrs_seq_label l
  831 handle_ibrs_\l:
  832         .endm
  833         .macro  ibrs_call_label l
  834         call    handle_ibrs_\l
  835         .endm
  836         .macro  ibrs_seq count
  837         ll=1
  838         .rept   \count
  839         ibrs_call_label %(ll)
  840         nop
  841         ibrs_seq_label %(ll)
  842         addq    $8,%rsp
  843         ll=ll+1
  844         .endr
  845         .endm
  846 
  847 /* all callers already saved %rax, %rdx, and %rcx */
  848 ENTRY(handle_ibrs_entry)
  849         cmpb    $0,hw_ibrs_active(%rip)
  850         je      1f
  851         movl    $MSR_IA32_SPEC_CTRL,%ecx
  852         rdmsr
  853         orl     $(IA32_SPEC_CTRL_IBRS|IA32_SPEC_CTRL_STIBP),%eax
  854         orl     $(IA32_SPEC_CTRL_IBRS|IA32_SPEC_CTRL_STIBP)>>32,%edx
  855         wrmsr
  856         movb    $1,PCPU(IBPB_SET)
  857         testl   $CPUID_STDEXT_SMEP,cpu_stdext_feature(%rip)
  858         jne     1f
  859         ibrs_seq 32
  860 1:      ret
  861 END(handle_ibrs_entry)
  862 
  863 ENTRY(handle_ibrs_exit)
  864         cmpb    $0,PCPU(IBPB_SET)
  865         je      1f
  866         movl    $MSR_IA32_SPEC_CTRL,%ecx
  867         rdmsr
  868         andl    $~(IA32_SPEC_CTRL_IBRS|IA32_SPEC_CTRL_STIBP),%eax
  869         andl    $~((IA32_SPEC_CTRL_IBRS|IA32_SPEC_CTRL_STIBP)>>32),%edx
  870         wrmsr
  871         movb    $0,PCPU(IBPB_SET)
  872 1:      ret
  873 END(handle_ibrs_exit)
  874 
  875 /* registers-neutral version, but needs stack */
  876 ENTRY(handle_ibrs_exit_rs)
  877         cmpb    $0,PCPU(IBPB_SET)
  878         je      1f
  879         pushq   %rax
  880         pushq   %rdx
  881         pushq   %rcx
  882         movl    $MSR_IA32_SPEC_CTRL,%ecx
  883         rdmsr
  884         andl    $~(IA32_SPEC_CTRL_IBRS|IA32_SPEC_CTRL_STIBP),%eax
  885         andl    $~((IA32_SPEC_CTRL_IBRS|IA32_SPEC_CTRL_STIBP)>>32),%edx
  886         wrmsr
  887         popq    %rcx
  888         popq    %rdx
  889         popq    %rax
  890         movb    $0,PCPU(IBPB_SET)
  891 1:      ret
  892 END(handle_ibrs_exit_rs)
  893 
  894         .noaltmacro
  895 
  896 /*
  897  * Flush L1D cache.  Load enough of the data from the kernel text
  898  * to flush existing L1D content.
  899  *
  900  * N.B. The function does not follow ABI calling conventions, it corrupts %rbx.
  901  * The vmm.ko caller expects that only %rax, %rdx, %rbx, %rcx, %r9, and %rflags
  902  * registers are clobbered.  The NMI handler caller only needs %r13 preserved.
  903  */
  904 ENTRY(flush_l1d_sw)
  905 #define L1D_FLUSH_SIZE  (64 * 1024)
  906         movq    $KERNBASE, %r9
  907         movq    $-L1D_FLUSH_SIZE, %rcx
  908         /*
  909          * pass 1: Preload TLB.
  910          * Kernel text is mapped using superpages.  TLB preload is
  911          * done for the benefit of older CPUs which split 2M page
  912          * into 4k TLB entries.
  913          */
  914 1:      movb    L1D_FLUSH_SIZE(%r9, %rcx), %al
  915         addq    $PAGE_SIZE, %rcx
  916         jne     1b
  917         xorl    %eax, %eax
  918         cpuid
  919         movq    $-L1D_FLUSH_SIZE, %rcx
  920         /* pass 2: Read each cache line. */
  921 2:      movb    L1D_FLUSH_SIZE(%r9, %rcx), %al
  922         addq    $64, %rcx
  923         jne     2b
  924         lfence
  925         ret
  926 #undef  L1D_FLUSH_SIZE
  927 END(flush_l1d_sw)

Cache object: 74e449c7daf792a69abac03c8a299f3a


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