projects / dragonfly.git / blame
| Commit | Line | Data |
|---|---|---|
| f66e9c25 SS |
1 | /*- |
| 2 | * Copyright 1996-1998 John D. Polstra. | |
| 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 | * | |
| 14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
| 15 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
| 16 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
| 17 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
| 18 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
| 19 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| 20 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| 21 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 22 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
| 23 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 24 | * | |
| 25 | * $FreeBSD: src/libexec/rtld-elf/amd64/rtld_start.S,v 1.5 2004/03/21 01:43:39 peter Exp $ | |
| f66e9c25 SS |
26 | */ |
| 27 | ||
| 5347affc MD |
28 | /* |
| 29 | * Dynamic program start. argv pointer is in %rdi. | |
| 30 | */ | |
| f66e9c25 SS |
31 | .text |
| 32 | .align 4 | |
| 33 | .globl resident_start | |
| 34 | .globl .rtld_start | |
| 35 | .type .rtld_start,@function | |
| 36 | resident_start: | |
| 37 | .rtld_start: | |
| 38 | xorq %rbp,%rbp # Clear frame pointer for good form | |
| 39 | subq $24,%rsp # A place to store exit procedure addr | |
| 40 | movq %rdi,%r12 | |
| 41 | movq %rsp,%rsi # save address of exit proc | |
| 42 | movq %rsp,%rdx # construct address of obj_main | |
| 43 | addq $8,%rdx | |
| 44 | call _rtld@PLT # Call rtld(sp); returns entry point | |
| 45 | popq %rsi # Get exit procedure address | |
| 46 | movq %r12,%rdi # *ap | |
| 47 | /* | |
| 48 | * At this point, %rax contains the entry point of the main program, and | |
| 49 | * %rdx contains a pointer to a termination function that should be | |
| 50 | * registered with atexit(). (crt1.o registers it.) | |
| 51 | */ | |
| 52 | .globl .rtld_goto_main | |
| 53 | .rtld_goto_main: # This symbol exists just to make debugging easier. | |
| 54 | jmp *%rax # Enter main program | |
| 55 | ||
| 56 | ||
| 57 | /* | |
| 58 | * Binder entry point. Control is transferred to here by code in the PLT. | |
| 59 | * On entry, there are two arguments on the stack. In ascending address | |
| 60 | * order, they are (1) "obj", a pointer to the calling object's Obj_Entry, | |
| 61 | * and (2) "reloff", the byte offset of the appropriate relocation entry | |
| 62 | * in the PLT relocation table. | |
| 63 | * | |
| 64 | * We are careful to preserve all registers, even the the caller-save | |
| 65 | * registers. That is because this code may be invoked by low-level | |
| 66 | * assembly-language code that is not ABI-compliant. | |
| 67 | * | |
| 68 | * Stack map: | |
| 69 | * reloff 0x60 | |
| 70 | * obj 0x58 | |
| 71 | * spare 0x50 | |
| 72 | * rflags 0x48 | |
| 73 | * rax 0x40 | |
| 74 | * rdx 0x38 | |
| 75 | * rcx 0x30 | |
| 76 | * rsi 0x28 | |
| 77 | * rdi 0x20 | |
| 78 | * r8 0x18 | |
| 79 | * r9 0x10 | |
| 80 | * r10 0x8 | |
| 81 | * r11 0x0 | |
| 82 | */ | |
| 83 | .align 4 | |
| 84 | .globl _rtld_bind_start | |
| 85 | .type _rtld_bind_start,@function | |
| 86 | _rtld_bind_start: | |
| 87 | subq $8,%rsp | |
| 88 | pushfq # Save rflags | |
| 89 | pushq %rax # Save %rax | |
| 90 | pushq %rdx # Save %rdx | |
| 91 | pushq %rcx # Save %rcx | |
| 92 | pushq %rsi # Save %rsi | |
| 93 | pushq %rdi # Save %rdi | |
| 94 | pushq %r8 # Save %r8 | |
| 95 | pushq %r9 # Save %r9 | |
| 96 | pushq %r10 # Save %r10 | |
| 97 | pushq %r11 # Save %r11 | |
| 5347affc MD |
98 | movq 0x58(%rsp),%rdi # Fetch obj argument (arg 1) |
| 99 | movq 0x60(%rsp),%rsi # Fetch reloff argument (arg 2) | |
| 100 | leaq 0x68(%rsp),%rdx # Fetch original stack pointer (arg 3) | |
| f66e9c25 SS |
101 | leaq (%rsi,%rsi,2),%rsi # multiply by 3 |
| 102 | leaq (,%rsi,8),%rsi # now 8, for 24 (sizeof Elf_Rela) | |
| 103 | ||
| 104 | call _rtld_bind@PLT # Transfer control to the binder | |
| 105 | /* Now %rax contains the entry point of the function being called. */ | |
| 106 | ||
| 107 | movq %rax,0x60(%rsp) # Store target over reloff argument | |
| 108 | popq %r11 # Restore %r11 | |
| 109 | popq %r10 # Restore %r10 | |
| 110 | popq %r9 # Restore %r9 | |
| 111 | popq %r8 # Restore %r8 | |
| 112 | popq %rdi # Restore %rdi | |
| 113 | popq %rsi # Restore %rsi | |
| 114 | popq %rcx # Restore %rcx | |
| 115 | popq %rdx # Restore %rdx | |
| 116 | popq %rax # Restore %rax | |
| 117 | popfq # Restore rflags | |
| 118 | leaq 16(%rsp),%rsp # Discard spare, obj, do not change rflags | |
| 119 | ret # "Return" to target address |