diff --git a/Pal/src/host/Linux/elf-x86_64.h b/Pal/src/host/Linux/elf-x86_64.h new file mode 100644 index 00000000..0bc4de9e --- /dev/null +++ b/Pal/src/host/Linux/elf-x86_64.h @@ -0,0 +1,79 @@ +/* -*- mode:c; c-file-style:"k&r"; c-basic-offset: 4; tab-width:4; indent-tabs-mode:nil; mode:auto-fill; fill-column:78; -*- */ +/* vim: set ts=4 sw=4 et tw=78 fo=cqt wm=0: */ + +/* Copyright (C) 2014 OSCAR lab, Stony Brook University + This file is part of Graphene Library OS. + + Graphene Library OS is free software: you can redistribute it and/or + modify it under the terms of the GNU General Public License + as published by the Free Software Foundation, either version 3 of the + License, or (at your option) any later version. + + Graphene Library OS 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 General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see . */ + +/* + * dl-machine-x86_64.h + * + * This files contain architecture-specific implementation of ELF dynamic + * relocation function. + * The source code is imported and modified from the GNU C Library. + */ + +#define ELF_MACHINE_NAME "x86_64" + +#include +#include +#include +#include "pal_internal.h" + +/* Return the link-time address of _DYNAMIC. Conveniently, this is the + first element of the GOT. This must be inlined in a function which + uses global data. */ +static inline Elf64_Addr __attribute__ ((unused)) +elf_machine_dynamic (void) +{ + Elf64_Addr addr; + + /* This works because we have our GOT address available in the small PIC + model. */ + addr = (Elf64_Addr) &_DYNAMIC; + + return addr; +} + +/* Return the run-time load address of the shared object. */ +static inline Elf64_Addr __attribute__ ((unused)) +elf_machine_load_address (void) +{ + Elf64_Addr addr; + + /* The easy way is just the same as on x86: + leaq _dl_start, %0 + leaq _dl_start(%%rip), %1 + subq %0, %1 + but this does not work with binutils since we then have + a R_X86_64_32S relocation in a shared lib. + + Instead we store the address of _dl_start in the data section + and compare it with the current value that we can get via + an RIP relative addressing mode. Note that this is the address + of _dl_start before any relocation performed at runtime. In case + the binary is prelinked the resulting "address" is actually a + load offset which is zero if the binary was loaded at the address + it is prelinked for. */ + + asm ("leaq " XSTRINGIFY(_ENTRY) "(%%rip), %0\n\t" + "subq 1f(%%rip), %0\n\t" + ".section\t.data.rel.ro\n" + "1:\t.quad " XSTRINGIFY(_ENTRY) "\n\t" + ".previous\n\t" + : "=r" (addr) : : "cc"); + + return addr; +}