| Current Path : /usr/src/libexec/rtld-elf/amd64/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //usr/src/libexec/rtld-elf/amd64/rtld_start.S |
/*- * Copyright 1996-1998 John D. Polstra. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * $FreeBSD: release/9.1.0/libexec/rtld-elf/amd64/rtld_start.S 229461 2012-01-04 03:37:41Z eadler $ */ .text .align 4 .globl .rtld_start .type .rtld_start,@function .rtld_start: xorq %rbp,%rbp # Clear frame pointer for good form subq $24,%rsp # A place to store exit procedure addr movq %rdi,%r12 movq %rsp,%rsi # save address of exit proc movq %rsp,%rdx # construct address of obj_main addq $8,%rdx call _rtld@PLT # Call rtld(sp); returns entry point popq %rsi # Get exit procedure address movq %r12,%rdi # *ap /* * At this point, %rax contains the entry point of the main program, and * %rdx contains a pointer to a termination function that should be * registered with atexit(). (crt1.o registers it.) */ .globl .rtld_goto_main .rtld_goto_main: # This symbol exists just to make debugging easier. jmp *%rax # Enter main program /* * Binder entry point. Control is transferred to here by code in the PLT. * On entry, there are two arguments on the stack. In ascending address * order, they are (1) "obj", a pointer to the calling object's Obj_Entry, * and (2) "reloff", the byte offset of the appropriate relocation entry * in the PLT relocation table. * * We are careful to preserve all registers, even the caller-save * registers. That is because this code may be invoked by low-level * assembly-language code that is not ABI-compliant. * * Stack map: * reloff 0x60 * obj 0x58 * spare 0x50 * rflags 0x48 * rax 0x40 * rdx 0x38 * rcx 0x30 * rsi 0x28 * rdi 0x20 * r8 0x18 * r9 0x10 * r10 0x8 * r11 0x0 */ .align 4 .globl _rtld_bind_start .type _rtld_bind_start,@function _rtld_bind_start: subq $8,%rsp pushfq # Save rflags pushq %rax # Save %rax pushq %rdx # Save %rdx pushq %rcx # Save %rcx pushq %rsi # Save %rsi pushq %rdi # Save %rdi pushq %r8 # Save %r8 pushq %r9 # Save %r9 pushq %r10 # Save %r10 pushq %r11 # Save %r11 movq 0x58(%rsp),%rdi # Fetch obj argument movq 0x60(%rsp),%rsi # Fetch reloff argument leaq (%rsi,%rsi,2),%rsi # multiply by 3 leaq (,%rsi,8),%rsi # now 8, for 24 (sizeof Elf_Rela) call _rtld_bind@PLT # Transfer control to the binder /* Now %rax contains the entry point of the function being called. */ movq %rax,0x60(%rsp) # Store target over reloff argument popq %r11 # Restore %r11 popq %r10 # Restore %r10 popq %r9 # Restore %r9 popq %r8 # Restore %r8 popq %rdi # Restore %rdi popq %rsi # Restore %rsi popq %rcx # Restore %rcx popq %rdx # Restore %rdx popq %rax # Restore %rax popfq # Restore rflags leaq 16(%rsp),%rsp # Discard spare, obj, do not change rflags ret # "Return" to target address .section .note.GNU-stack,"",%progbits