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/*-
* 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.
*
* $FreeBSD$
*/
.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:
.cfi_startproc
.cfi_adjust_cfa_offset 16
subq $8,%rsp
.cfi_adjust_cfa_offset 8
pushfq # Save rflags
.cfi_adjust_cfa_offset 8
pushq %rax # Save %rax
.cfi_adjust_cfa_offset 8
.cfi_offset %rax,-32
pushq %rdx # Save %rdx
.cfi_adjust_cfa_offset 8
.cfi_offset %rdx,-40
pushq %rcx # Save %rcx
.cfi_adjust_cfa_offset 8
.cfi_offset %rcx,-48
pushq %rsi # Save %rsi
.cfi_adjust_cfa_offset 8
.cfi_offset %rsi,-56
pushq %rdi # Save %rdi
.cfi_adjust_cfa_offset 8
.cfi_offset %rdi,-64
pushq %r8 # Save %r8
.cfi_adjust_cfa_offset 8
.cfi_offset %r8,-72
pushq %r9 # Save %r9
.cfi_adjust_cfa_offset 8
.cfi_offset %r9,-80
pushq %r10 # Save %r10
.cfi_adjust_cfa_offset 8
.cfi_offset %r10,-88
pushq %r11 # Save %r11
.cfi_adjust_cfa_offset 8
.cfi_offset %r11,-96
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
.cfi_adjust_cfa_offset -8
.cfi_restore %r11
popq %r10 # Restore %r10
.cfi_adjust_cfa_offset -8
.cfi_restore %r10
popq %r9 # Restore %r9
.cfi_adjust_cfa_offset -8
.cfi_restore %r9
popq %r8 # Restore %r8
.cfi_adjust_cfa_offset -8
.cfi_restore %r8
popq %rdi # Restore %rdi
.cfi_adjust_cfa_offset -8
.cfi_restore %rdi
popq %rsi # Restore %rsi
.cfi_adjust_cfa_offset -8
.cfi_restore %rsi
popq %rcx # Restore %rcx
.cfi_adjust_cfa_offset -8
.cfi_restore %rcx
popq %rdx # Restore %rdx
.cfi_adjust_cfa_offset -8
.cfi_restore %rdx
popq %rax # Restore %rax
.cfi_adjust_cfa_offset -8
.cfi_restore %rax
popfq # Restore rflags
.cfi_adjust_cfa_offset -8
leaq 16(%rsp),%rsp # Discard spare, obj, do not change rflags
ret # "Return" to target address
.cfi_endproc
.size _rtld_bind_start, . - _rtld_bind_start
.section .note.GNU-stack,"",%progbits
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