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/* Machine-dependent ELF dynamic relocation inline functions. FreeBSD/amd64 version.
Copyright (C) 2006 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Petr Salinger, 2006.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include_next <dl-machine.h>
#undef RTLD_START
/* Initial entry point code for the dynamic linker.
The C function `_dl_start' is the real entry point;
its return value is the user program's entry point. */
#define RTLD_START asm ("\n\
.text\n\
.align 16\n\
.globl _start\n\
# we dont use it: .globl _dl_start_user\n\
_start:\n\
# align stack.\n\
andq $-16, %rsp\n\
# save argument pointer.\n\
movq %rdi, %r13\n\
call _dl_start\n\
# we dont use it: _dl_start_user:\n\
# Save the user entry point address in %r12.\n\
movq %rax, %r12\n\
# See if we were run as a command with the executable file\n\
# name as an extra leading argument.\n\
movl _dl_skip_args(%rip), %eax\n\
# get the original argument count.\n\
movq 0(%r13), %rdx\n\
# Adjust the pointer to skip _dl_skip_args words.\n\
leaq (%r13,%rax,8), %r13\n\
# Subtract _dl_skip_args from argc.\n\
subl %eax, %edx\n\
# Put argc on adjusted place\n\
movq %rdx, 0(%r13)\n\
# Call _dl_init (struct link_map *main_map, int argc, char **argv, char **env)\n\
# argc -> rsi\n\
movq %rdx, %rsi\n\
# _dl_loaded -> rdi\n\
movq _rtld_local(%rip), %rdi\n\
# env -> rcx\n\
leaq 16(%r13,%rdx,8), %rcx\n\
# argv -> rdx\n\
leaq 8(%r13), %rdx\n\
# Clear %rbp to mark outermost frame obviously even for constructors.\n\
xorl %ebp, %ebp\n\
# Call the function to run the initializers.\n\
call _dl_init@PLT\n\
# Pass our finalizer function to the user in %rdx, as per ELF ABI draft.\n\
leaq _dl_fini(%rip), %rdx\n\
# And make sure %rdi points to argc stored on the stack.\n\
movq %r13, %rdi\n\
# Pass finalizer function also in %rsi, as per C calling convention.\n\
movq %rdx, %rsi\n\
# Jump to the user's entry point.\n\
jmp *%r12\n\
.previous\n\
");
#if 0
Under FreeBSD:
#define AT_EXECPATH 15 /* Path to the executable. */
Under Linux:
#define AT_PLATFORM 15 /* String identifying platform. */
Filled entries from kernel:
if (args->execfd != -1)
AUXARGS_ENTRY(pos, AT_EXECFD, args->execfd);
AUXARGS_ENTRY(pos, AT_PHDR, args->phdr);
AUXARGS_ENTRY(pos, AT_PHENT, args->phent);
AUXARGS_ENTRY(pos, AT_PHNUM, args->phnum);
AUXARGS_ENTRY(pos, AT_PAGESZ, args->pagesz);
AUXARGS_ENTRY(pos, AT_FLAGS, args->flags);
AUXARGS_ENTRY(pos, AT_ENTRY, args->entry);
AUXARGS_ENTRY(pos, AT_BASE, args->base);
if (imgp->execpathp != 0)
AUXARGS_ENTRY(pos, AT_EXECPATH, imgp->execpathp);
AUXARGS_ENTRY(pos, AT_NULL, 0);
#endif
#ifndef _DL_MACHINE_KFREEBSD
#define _DL_MACHINE_KFREEBSD
static inline void __attribute__ ((unused))
dl_platform_kfreebsd_x86_64_init (void)
{
/* This calls cpuid and and fills dl_x86_cpu_features */
DL_PLATFORM_INIT;
/* we don't have reasonable AT_PLATFORM from kernel
use cpuid to guess AT_HWCAP */
GLRO(dl_hwcap) = GLRO(dl_x86_cpu_features).cpuid[COMMON_CPUID_INDEX_1].edx;
GLRO(dl_platform) = ELF_MACHINE_NAME;
}
#undef DL_PLATFORM_INIT
#define DL_PLATFORM_INIT dl_platform_kfreebsd_x86_64_init ()
#endif
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