genode/repos/base/src/lib/ldso/arm/relocation.h

119 lines
2.9 KiB
C++

/**
* \brief ARM specific relocations
* \author Sebastian Sumpf
* \date 2014-10-26
*/
/*
* Copyright (C) 2014 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU General Public License version 2.
*/
#ifndef _INCLUDE__ARM__RELOCATION_H_
#define _INCLUDE__ARM__RELOCATION_H_
#include <relocation_generic.h>
namespace Linker {
enum Reloc_types {
R_ABS32 = 2,
R_REL32 = 3,
R_COPY = 20,
R_GLOB_DAT = 21,
R_JMPSLOT = 22,
R_RELATIVE = 23,
};
class Reloc_non_plt;
typedef Reloc_plt_generic<Elf::Rel, DT_REL, R_JMPSLOT> Reloc_plt;
typedef Reloc_jmpslot_generic<Elf::Rel, DT_REL, false> Reloc_jmpslot;
typedef Reloc_bind_now_generic<Elf::Rel, DT_REL> Reloc_bind_now;
};
class Linker::Reloc_non_plt : public Reloc_non_plt_generic
{
private:
void _rel32(Elf::Rel const *rel, Elf::Addr *addr)
{
Elf::Addr reloc_base;
Elf::Sym const *sym;
if (!(sym = locate_symbol(rel->sym(), _dag, &reloc_base)))
return;
/* S + A - P */
*addr = reloc_base + sym->st_value - (Elf::Addr)addr + *addr;
trace("REL32", (unsigned long)addr, *addr, 0);
}
void _glob_dat(Elf::Rel const *rel, Elf::Addr *addr, bool no_addend)
{
Elf::Addr reloc_base;
Elf::Sym const *sym;
if (!(sym = locate_symbol(rel->sym(), _dag, &reloc_base)))
return;
Elf::Addr addend = no_addend ? 0 : *addr;
/* S + A */
*addr = addend + reloc_base + sym->st_value;
trace("GLOB_DAT", (unsigned long)addr, *addr, 0);
}
void _relative(Elf::Addr *addr)
{
/*
* This ommits the linker and the binary, the linker has relative
* relocations within its text-segment (e.g., 'initial_sp' and friends), which
* we cannot write to from here).
*/
if (_dag->obj->reloc_base())
*addr += _dag->obj->reloc_base();
}
public:
Reloc_non_plt(Dag const *dag, Elf::Rela const *, unsigned long)
: Reloc_non_plt_generic(dag)
{
PERR("LD: DT_RELA not supported");
throw Incompatible();
}
Reloc_non_plt(Dag const *dag, Elf::Rel const *rel, unsigned long size, bool second_pass)
: Reloc_non_plt_generic(dag)
{
Elf::Rel const *end = rel + (size / sizeof(Elf::Rel));
for (; rel < end; rel++) {
Elf::Addr *addr = (Elf::Addr *)(_dag->obj->reloc_base() + rel->offset);
if (second_pass && rel->type() != R_GLOB_DAT)
continue;
switch (rel->type()) {
case R_REL32 : _rel32(rel, addr); break;
case R_COPY : _copy<Elf::Rel>(rel, addr); break;
case R_ABS32 :
case R_GLOB_DAT: _glob_dat(rel, addr, second_pass); break;
case R_RELATIVE: _relative(addr); break;
default:
trace("UNKREL", rel->type(), 0, 0);
if (_dag->root) {
PWRN("LD: Unkown relocation %u", rel->type());
throw Incompatible();
}
break;
}
}
}
};
#endif /* _INCLUDE__ARM__RELOCATION_H_ */