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
 126 #if __x86_64__
 127         .data
 128         .align 3
 129 __dyld_start_static:
 130         .quad   __dyld_start
 131
 132 # stable entry points into dyld
 133         .text
 134         .align 2
 135         .globl  _stub_binding_helper
 136 _stub_binding_helper:
 137         jmp     _stub_binding_helper_interface
 138         nop
 139         nop
 140         nop
 141         .globl  _dyld_func_lookup
 142 _dyld_func_lookup:
 143         jmp     __Z18lookupDyldFunctionPKcPm
 144
 145         .text
 146         .align 2,0x90
 147         .globl __dyld_start
 148 __dyld_start:
 149         pushq   $0              # push a zero for debugger end of frames marker
 150         movq    %rsp,%rbp       # pointer to base of kernel frame
 151         andq    $-16,%rsp       # force SSE alignment
 152
 153         # call dyldbootstrap::start(app_mh, argc, argv, slide)
 154         movq    8(%rbp),%rdi    # param1 = mh into %rdi
 155         movl    16(%rbp),%esi   # param2 = argc into %esi
 156         leaq    24(%rbp),%rdx   # param3 = &argv[0] into %rdx
 157         movq    __dyld_start_static(%rip), %r8
 158         leaq    __dyld_start(%rip), %rcx
 159         subq     %r8, %rcx      # param4 = slide into %rcx
 160         call    __ZN13dyldbootstrap5startEPK11mach_headeriPPKcl
 161
 162         # clean up stack and jump to result
 163         movq    %rbp,%rsp       # restore the unaligned stack pointer
 164         addq    $16,%rsp        # remove the mh argument, and debugger end frame marker
 165         movq    $0,%rbp         # restore ebp back to zero
 166         jmp     *%rax           # jump to the entry point
 167
 168 #endif /* __x86_64__ */
 169
 170 #if __ppc__ || __ppc64__
 171 #include <architecture/ppc/mode_independent_asm.h>
 172
 173         .data
 174         .align 2
 175 __dyld_start_static_picbase:
 176         .g_long   L__dyld_start_picbase
 177
 178 #if __ppc__
 179         .set L_mh_offset,0
 180         .set L_argc_offset,4
 181         .set L_argv_offset,8
 182 #else
 183         .set L_mh_offset,0
 184         .set L_argc_offset,8    ; stack is 8-byte aligned and there is a 4-byte hole between argc and argv
 185         .set L_argv_offset,16
 186 #endif
 187
 188         .text
 189         .align 2
 190 ; stable entry points into dyld
 191         .globl  _stub_binding_helper
 192 _stub_binding_helper:
 193         b       _stub_binding_helper_interface
 194         nop
 195         .globl  _dyld_func_lookup
 196 _dyld_func_lookup:
 197         b       __Z18lookupDyldFunctionPKcPm
 198
 199
 200
 201         .text
 202         .align 2
 203 __dyld_start:
 204         mr      r26,r1          ; save original stack pointer into r26
 205         subi    r1,r1,GPR_BYTES ; make space for linkage
 206         clrrgi  r1,r1,5         ; align to 32 bytes
 207         addi    r0,0,0          ; load 0 into r0
 208         stg     r0,0(r1)        ; terminate initial stack frame
 209         stgu    r1,-SF_MINSIZE(r1); allocate minimal stack frame
 210
 211         ; call dyldbootstrap::start(app_mh, argc, argv, slide)
 212         lg      r3,L_mh_offset(r26)     ; r3 = mach_header
 213         lwz     r4,L_argc_offset(r26)   ; r4 = argc (int == 4 bytes)
 214         addi    r5,r26,L_argv_offset    ; r5 = argv
 215         bcl     20,31,L__dyld_start_picbase
 216 L__dyld_start_picbase:
 217         mflr    r31             ; put address of L__dyld_start_picbase in r31
 218         addis   r6,r31,ha16(__dyld_start_static_picbase-L__dyld_start_picbase)
 219         lg      r6,lo16(__dyld_start_static_picbase-L__dyld_start_picbase)(r6)
 220         subf    r6,r6,r31       ; r6 = slide
 221         bl      __ZN13dyldbootstrap5startEPK11mach_headeriPPKcl
 222
 223         ; clean up stack and jump to result
 224         mtctr   r3              ; Put entry point in count register
 225         mr      r12,r3          ;  also put in r12 for ABI convention.
 226         addi    r1,r26,GPR_BYTES; Restore the stack pointer and remove the
 227                                 ;  mach_header argument.
 228         bctr                    ; jump to the program's entry point
 229
 230         .globl dyld_stub_binding_helper
 231 dyld_stub_binding_helper:
 232         trap
 233 L_end:
 234 #endif /* __ppc__ */
 235
 236