bsd/dev/i386/munge.s

   1 /*
   2  * Coyright (c) 2005-2006 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 /*
  30  * Syscall argument mungers.
  31  *
  32  * The data to be munged has been explicitly copied in to the argument area,
  33  * and will be munged in place in the uu_arg[] array.  Because of this, the
  34  * functions all take the same arguments as their PPC equivalents, but the
  35  * first argument is ignored.  These mungers are for 32-bit app's syscalls,
  36  * since 64-bit args are stored into the save area (which overlays the
  37  * uu_args) in the order the syscall ABI calls for.
  38  *
  39  * The issue is that the incoming args are 32-bit, but we must expand
  40  * them in place into 64-bit args, as if they were from a 64-bit process.
  41  *
  42  * There are several functions in this file.  Each takes two parameters:
  43  *
  44  *      void    munge_XXXX( const void *regs, void *uu_args);
  45  *
  46  * The name of the function encodes the number and type of the parameters,
  47  * as follows:
  48  *
  49  *      w = a 32-bit value such as an int or a 32-bit ptr, that does not
  50  *          require sign extension.  These are handled by zeroing a word
  51  *          of output, and copying a word from input to output.
  52  *
  53  *      s = a 32-bit value such as a long, which must be sign-extended to
  54  *          a 64-bit long-long in the uu_args.  These are handled by
  55  *          loading a word of input and sign extending it to a double,
  56  *          and storing two words of output.
  57  *
  58  *      l = a 64-bit long-long.  These are handled by copying two words
  59  *          of input to the output.
  60  *
  61  * For example, "munge_wls" takes a word, a long-long, and a word.  This
  62  * takes four words in the uu_arg[] area: the first word is in one, the
  63  * long-long takes two, and the final word is in the fourth.  We store six
  64  * words: the low word is left in place, followed by a 0, followed by the
  65  * two words of the long-long, followed by the low word and the sign extended
  66  * high word of the preceeding low word.
  67  *
  68  * Because this is an in-place modification, we actually start at the end
  69  * of uu_arg[] and work our way back to the beginning of the array.
  70  *
  71  * As you can see, we save a lot of code by collapsing mungers that are
  72  * prefixes or suffixes of each other.
  73  */
  74 #include <i386/asm.h>
  75
  76 ENTRY(munge_w)
  77         movl    8(%esp),%ecx    // get &uu_args
  78         movl    $0,4(%ecx)
  79         ret
  80
  81 ENTRY(munge_ww)
  82         movl    8(%esp),%ecx    // get &uu_args
  83         xorl    %edx,%edx
  84         jmp     Lw2
  85 ENTRY(munge_www)
  86         movl    8(%esp),%ecx    // get &uu_args
  87         xorl    %edx,%edx
  88         jmp     Lw3
  89 ENTRY(munge_wwww)
  90         movl    8(%esp),%ecx    // get &uu_args
  91         xorl    %edx,%edx
  92         jmp     Lw4
  93 ENTRY(munge_wwwww)
  94         movl    8(%esp),%ecx    // get &uu_args
  95         xorl    %edx,%edx
  96         jmp     Lw5
  97 ENTRY(munge_wwwwww)
  98         movl    8(%esp),%ecx    // get &uu_args
  99         xorl    %edx,%edx
 100         jmp     Lw6
 101 ENTRY(munge_wwwwwww)
 102         movl    8(%esp),%ecx    // get &uu_args
 103         xorl    %edx,%edx
 104         jmp     Lw7
 105 ENTRY(munge_wwwwwwww)
 106         movl    8(%esp),%ecx    // get &uu_args
 107         xorl    %edx,%edx
 108         movl    28(%ecx),%eax
 109         movl    %eax,56(%ecx)
 110         movl    %edx,60(%ecx)
 111 Lw7:
 112         movl    24(%ecx),%eax
 113         movl    %eax,48(%ecx)
 114         movl    %edx,52(%ecx)
 115 Lw6:
 116         movl    20(%ecx),%eax
 117         movl    %eax,40(%ecx)
 118         movl    %edx,44(%ecx)
 119 Lw5:
 120         movl    16(%ecx),%eax
 121         movl    %eax,32(%ecx)
 122         movl    %edx,36(%ecx)
 123 Lw4:
 124         movl    12(%ecx),%eax
 125         movl    %eax,24(%ecx)
 126         movl    %edx,28(%ecx)
 127 Lw3:
 128         movl    8(%ecx),%eax
 129         movl    %eax,16(%ecx)
 130         movl    %edx,20(%ecx)
 131 Lw2:
 132         movl    4(%ecx),%eax
 133         movl    %eax,8(%ecx)
 134         movl    %edx,12(%ecx)
 135         movl    %edx,4(%ecx)
 136         ret
 137
 138
 139 Entry(munge_wl)                 /* Costs an extra w move to do this */
 140 ENTRY(munge_wlw)
 141         movl    8(%esp),%ecx    // get &uu_args
 142         xorl    %edx,%edx
 143         movl    12(%ecx),%eax
 144         movl    %eax,16(%ecx)
 145         movl    %edx,20(%ecx)
 146         movl    8(%ecx),%eax
 147         movl    %eax,12(%ecx)
 148         movl    4(%ecx),%eax
 149         movl    %eax,8(%ecx)
 150         movl    %edx,4(%ecx)
 151         ret
 152
 153 ENTRY(munge_wwwl)
 154         movl    8(%esp),%ecx    // get &uu_args
 155         xorl    %edx,%edx
 156         movl    12(%ecx),%eax
 157         movl    %eax,24(%ecx)
 158         movl    16(%ecx),%eax
 159         movl    %eax,28(%ecx)
 160         jmp     Lw3
 161
 162 ENTRY(munge_wwwwl)
 163         movl    8(%esp),%ecx    // get &uu_args
 164         xorl    %edx,%edx
 165         movl    16(%ecx),%eax
 166         movl    %eax,32(%ecx)
 167         movl    20(%ecx),%eax
 168         movl    %eax,36(%ecx)
 169         jmp     Lw4
 170
 171 ENTRY(munge_wwwwwl)
 172         movl    8(%esp),%ecx    // get &uu_args
 173         xorl    %edx,%edx
 174         movl    20(%ecx),%eax
 175         movl    %eax,40(%ecx)
 176         movl    24(%ecx),%eax
 177         movl    %eax,44(%ecx)
 178         jmp     Lw5
 179
 180 ENTRY(munge_wsw)
 181         movl    8(%esp),%ecx    // get &uu_args
 182         movl    8(%ecx),%eax
 183         movl    %eax,16(%ecx)
 184         movl    $0,20(%ecx)
 185         movl    4(%ecx),%eax
 186         cltd
 187         movl    %eax,8(%ecx)
 188         movl    %edx,12(%ecx)
 189         movl    $0,4(%ecx)
 190         ret
 191
 192 ENTRY(munge_wws)
 193         movl    8(%esp),%ecx    // get &uu_args
 194         movl    8(%ecx),%eax
 195         cltd
 196         movl    %eax,16(%ecx)
 197         movl    %edx,20(%ecx)
 198         xorl    %edx,%edx
 199         jmp     Lw2
 200
 201 ENTRY(munge_wwwsw)
 202         movl    8(%esp),%ecx    // get &uu_args
 203         movl    16(%ecx),%eax
 204         movl    %eax,32(%ecx)
 205         movl    $0,36(%ecx)
 206         movl    12(%ecx),%eax
 207         cltd
 208         movl    %eax,24(%ecx)
 209         movl    %edx,28(%ecx)
 210         xorl    %edx,%edx
 211         jmp     Lw3