src/dyldStartup.s

   1 /*
   2  * Copyright (c) 1999-2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23 /*
  24  * C runtime startup for i386 and ppc interface to the dynamic linker.
  25  * This is the same as the entry point in crt0.o with the addition of the
  26  * address of the mach header passed as the an extra first argument.
  27  *
  28  * Kernel sets up stack frame to look like:
  29  *
  30  *      | STRING AREA |
  31  *      +-------------+
  32  *      |      0      |
  33 *       +-------------+
  34  *      |  apple[n]   |
  35  *      +-------------+
  36  *             :
  37  *      +-------------+
  38  *      |  apple[0]   |
  39  *      +-------------+
  40  *      |      0      |
  41  *      +-------------+
  42  *      |    env[n]   |
  43  *      +-------------+
  44  *             :
  45  *             :
  46  *      +-------------+
  47  *      |    env[0]   |
  48  *      +-------------+
  49  *      |      0      |
  50  *      +-------------+
  51  *      | arg[argc-1] |
  52  *      +-------------+
  53  *             :
  54  *             :
  55  *      +-------------+
  56  *      |    arg[0]   |
  57  *      +-------------+
  58  *      |     argc    |
  59  *      +-------------+
  60  * sp-> |      mh     | address of where the a.out's file offset 0 is in memory
  61  *      +-------------+
  62  *
  63  *      Where arg[i] and env[i] point into the STRING AREA
  64  */
  65
  66         .globl __dyld_start
  67
  68
  69 #ifdef __i386__
  70         .data
  71 __dyld_start_static_picbase:
  72         .long   L__dyld_start_picbase
  73
  74
  75         .text
  76         .align 2
  77 # stable entry points into dyld
  78         .globl  _stub_binding_helper
  79 _stub_binding_helper:
  80         jmp     _stub_binding_helper_interface
  81         nop
  82         nop
  83         nop
  84         .globl  _dyld_func_lookup
  85 _dyld_func_lookup:
  86         jmp     __Z18lookupDyldFunctionPKcPm
  87
  88         .text
  89         .align  4, 0x90
  90         .globl __dyld_start
  91 __dyld_start:
  92         pushl   $0              # push a zero for debugger end of frames marker
  93         movl    %esp,%ebp       # pointer to base of kernel frame
  94         andl    $-16,%esp       # force SSE alignment
  95
  96         # call dyldbootstrap::start(app_mh, argc, argv, slide)
  97         call    L__dyld_start_picbase
  98 L__dyld_start_picbase:
  99         popl    %ebx            # set %ebx to runtime value of picbase
 100         movl    __dyld_start_static_picbase-L__dyld_start_picbase(%ebx), %eax
 101         subl    %eax, %ebx      # slide = L__dyld_start_picbase - [__dyld_start_static_picbase]
 102         pushl   %ebx            # param4 = slide
 103         lea     12(%ebp),%ebx
 104         pushl   %ebx            # param3 = argv
 105         movl    8(%ebp),%ebx
 106         pushl   %ebx            # param2 = argc
 107         movl    4(%ebp),%ebx
 108         pushl   %ebx            # param1 = mh
 109         call    __ZN13dyldbootstrap5startEPK11mach_headeriPPKcl
 110
 111         # clean up stack and jump to result
 112         movl    %ebp,%esp       # restore the unaligned stack pointer
 113         addl    $8,%esp         # remove the mh argument, and debugger end
 114                                 #  frame marker
 115         movl    $0,%ebp         # restore ebp back to zero
 116         jmp     %eax            # jump to the entry point
 117
 118
 119         .globl dyld_stub_binding_helper
 120 dyld_stub_binding_helper:
 121         hlt
 122 L_end:
 123 #endif /* __i386__ */
 124
 125 #if __ppc__ || __ppc64__
 126 #include <architecture/ppc/mode_independent_asm.h>
 127
 128         .data
 129         .align 2
 130 __dyld_start_static_picbase:
 131         .g_long   L__dyld_start_picbase
 132
 133 #if __ppc__
 134         .set L_mh_offset,0
 135         .set L_argc_offset,4
 136         .set L_argv_offset,8
 137 #else
 138         .set L_mh_offset,0
 139         .set L_argc_offset,8    ; stack is 8-byte aligned and there is a 4-byte hole between argc and argv
 140         .set L_argv_offset,16
 141 #endif
 142
 143         .text
 144         .align 2
 145 ; stable entry points into dyld
 146         .globl  _stub_binding_helper
 147 _stub_binding_helper:
 148         b       _stub_binding_helper_interface
 149         nop
 150         .globl  _dyld_func_lookup
 151 _dyld_func_lookup:
 152         b       __Z18lookupDyldFunctionPKcPm
 153
 154
 155
 156         .text
 157         .align 2
 158 __dyld_start:
 159         mr      r26,r1          ; save original stack pointer into r26
 160         subi    r1,r1,GPR_BYTES ; make space for linkage
 161         clrrgi  r1,r1,5         ; align to 32 bytes
 162         addi    r0,0,0          ; load 0 into r0
 163         stg     r0,0(r1)        ; terminate initial stack frame
 164         stgu    r1,-SF_MINSIZE(r1); allocate minimal stack frame
 165
 166         ; call dyldbootstrap::start(app_mh, argc, argv, slide)
 167         lg      r3,L_mh_offset(r26)     ; r3 = mach_header
 168         lwz     r4,L_argc_offset(r26)   ; r4 = argc (int == 4 bytes)
 169         addi    r5,r26,L_argv_offset    ; r5 = argv
 170         bcl     20,31,L__dyld_start_picbase
 171 L__dyld_start_picbase:
 172         mflr    r31             ; put address of L__dyld_start_picbase in r31
 173         addis   r6,r31,ha16(__dyld_start_static_picbase-L__dyld_start_picbase)
 174         lg      r6,lo16(__dyld_start_static_picbase-L__dyld_start_picbase)(r6)
 175         subf    r6,r6,r31       ; r6 = slide
 176         bl      __ZN13dyldbootstrap5startEPK11mach_headeriPPKcl
 177
 178         ; clean up stack and jump to result
 179         mtctr   r3              ; Put entry point in count register
 180         mr      r12,r3          ;  also put in r12 for ABI convention.
 181         addi    r1,r26,GPR_BYTES; Restore the stack pointer and remove the
 182                                 ;  mach_header argument.
 183         bctr                    ; jump to the program's entry point
 184
 185         .globl dyld_stub_binding_helper
 186 dyld_stub_binding_helper:
 187         trap
 188 L_end:
 189 #endif /* __ppc__ */
 190
 191