NetBSD-5.0.2/libexec/ld.elf_so/arch/mips/mips_reloc.c
/* $NetBSD: mips_reloc.c,v 1.53 2008/07/24 04:39:25 matt Exp $ */
/*
* Copyright 1997 Michael L. Hitch <mhitch@montana.edu>
* Portions copyright 2002 Charles M. Hannum <root@ihack.net>
* 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.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* 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.
*/
#include <sys/cdefs.h>
#ifndef lint
__RCSID("$NetBSD: mips_reloc.c,v 1.53 2008/07/24 04:39:25 matt Exp $");
#endif /* not lint */
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <string.h>
#include "debug.h"
#include "rtld.h"
#define SUPPORT_OLD_BROKEN_LD
void _rtld_bind_start(void);
void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr);
caddr_t _rtld_bind(Elf_Word, Elf_Addr, Elf_Addr, Elf_Addr);
/*
* It is possible for the compiler to emit relocations for unaligned data.
* We handle this situation with these inlines.
*/
#define RELOC_ALIGNED_P(x) \
(((uintptr_t)(x) & (sizeof(void *) - 1)) == 0)
static inline Elf_Addr
load_ptr(void *where)
{
if (__predict_true(RELOC_ALIGNED_P(where)))
return *(Elf_Addr *)where;
else {
Elf_Addr res;
(void)memcpy(&res, where, sizeof(res));
return res;
}
}
static inline void
store_ptr(void *where, Elf_Addr val)
{
if (__predict_true(RELOC_ALIGNED_P(where)))
*(Elf_Addr *)where = val;
else
(void)memcpy(where, &val, sizeof(val));
}
void
_rtld_setup_pltgot(const Obj_Entry *obj)
{
obj->pltgot[0] = (Elf_Addr) &_rtld_bind_start;
/* XXX only if obj->pltgot[1] & 0x80000000 ?? */
obj->pltgot[1] |= (Elf_Addr) obj;
}
void
_rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase)
{
const Elf_Rel *rel = 0, *rellim;
Elf_Addr relsz = 0;
void *where;
const Elf_Sym *symtab = NULL, *sym;
Elf_Addr *got = NULL;
Elf_Word local_gotno = 0, symtabno = 0, gotsym = 0;
int i;
for (; dynp->d_tag != DT_NULL; dynp++) {
switch (dynp->d_tag) {
case DT_REL:
rel = (const Elf_Rel *)(relocbase + dynp->d_un.d_ptr);
break;
case DT_RELSZ:
relsz = dynp->d_un.d_val;
break;
case DT_SYMTAB:
symtab = (const Elf_Sym *)(relocbase + dynp->d_un.d_ptr);
break;
case DT_PLTGOT:
got = (Elf_Addr *)(relocbase + dynp->d_un.d_ptr);
break;
case DT_MIPS_LOCAL_GOTNO:
local_gotno = dynp->d_un.d_val;
break;
case DT_MIPS_SYMTABNO:
symtabno = dynp->d_un.d_val;
break;
case DT_MIPS_GOTSYM:
gotsym = dynp->d_un.d_val;
break;
}
}
i = (got[1] & 0x80000000) ? 2 : 1;
/* Relocate the local GOT entries */
got += i;
for (; i < local_gotno; i++)
*got++ += relocbase;
sym = symtab + gotsym;
/* Now do the global GOT entries */
for (i = gotsym; i < symtabno; i++) {
*got = sym->st_value + relocbase;
++sym;
++got;
}
rellim = (const Elf_Rel *)((caddr_t)rel + relsz);
for (; rel < rellim; rel++) {
where = (void *)(relocbase + rel->r_offset);
switch (ELF_R_TYPE(rel->r_info)) {
case R_TYPE(NONE):
break;
case R_TYPE(REL32):
assert(ELF_R_SYM(rel->r_info) < gotsym);
sym = symtab + ELF_R_SYM(rel->r_info);
assert(ELF_ST_BIND(sym->st_info) == STB_LOCAL);
store_ptr(where, load_ptr(where) + relocbase);
break;
default:
abort();
}
}
}
int
_rtld_relocate_nonplt_objects(const Obj_Entry *obj)
{
const Elf_Rel *rel;
Elf_Addr *got = obj->pltgot;
const Elf_Sym *sym, *def;
const Obj_Entry *defobj;
int i;
#ifdef SUPPORT_OLD_BROKEN_LD
int broken;
#endif
#ifdef SUPPORT_OLD_BROKEN_LD
broken = 0;
sym = obj->symtab;
for (i = 1; i < 12; i++)
if (sym[i].st_info == ELF_ST_INFO(STB_LOCAL, STT_NOTYPE))
broken = 1;
dbg(("%s: broken=%d", obj->path, broken));
#endif
i = (got[1] & 0x80000000) ? 2 : 1;
/* Relocate the local GOT entries */
got += i;
for (; i < obj->local_gotno; i++)
*got++ += (Elf_Addr)obj->relocbase;
sym = obj->symtab + obj->gotsym;
/* Now do the global GOT entries */
for (i = obj->gotsym; i < obj->symtabno; i++) {
rdbg((" doing got %d sym %p (%s, %x)", i - obj->gotsym, sym,
sym->st_name + obj->strtab, *got));
#ifdef SUPPORT_OLD_BROKEN_LD
if (ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
broken && sym->st_shndx == SHN_UNDEF) {
/*
* XXX DANGER WILL ROBINSON!
* You might think this is stupid, as it intentionally
* defeats lazy binding -- and you'd be right.
* Unfortunately, for lazy binding to work right, we
* need to a way to force the GOT slots used for
* function pointers to be resolved immediately. This
* is supposed to be done automatically by the linker,
* by not outputting a PLT slot and setting st_value
* to 0 if there are non-PLT references, but older
* versions of GNU ld do not do this.
*/
def = _rtld_find_symdef(i, obj, &defobj, false);
if (def == NULL)
return -1;
*got = def->st_value + (Elf_Addr)defobj->relocbase;
} else
#endif
if (ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
sym->st_value != 0 && sym->st_shndx == SHN_UNDEF) {
/*
* If there are non-PLT references to the function,
* st_value should be 0, forcing us to resolve the
* address immediately.
*
* XXX DANGER WILL ROBINSON!
* The linker is not outputting PLT slots for calls to
* functions that are defined in the same shared
* library. This is a bug, because it can screw up
* link ordering rules if the symbol is defined in
* more than one module. For now, if there is a
* definition, we fail the test above and force a full
* symbol lookup. This means that all intra-module
* calls are bound immediately. - mycroft, 2003/09/24
*/
*got = sym->st_value + (Elf_Addr)obj->relocbase;
} else if (sym->st_info == ELF_ST_INFO(STB_GLOBAL, STT_SECTION)) {
/* Symbols with index SHN_ABS are not relocated. */
if (sym->st_shndx != SHN_ABS)
*got = sym->st_value +
(Elf_Addr)obj->relocbase;
} else {
def = _rtld_find_symdef(i, obj, &defobj, false);
if (def == NULL)
return -1;
*got = def->st_value + (Elf_Addr)defobj->relocbase;
}
rdbg((" --> now %x", *got));
++sym;
++got;
}
got = obj->pltgot;
for (rel = obj->rel; rel < obj->rellim; rel++) {
void *where;
Elf_Addr tmp;
unsigned long symnum;
where = obj->relocbase + rel->r_offset;
symnum = ELF_R_SYM(rel->r_info);
switch (ELF_R_TYPE(rel->r_info)) {
case R_TYPE(NONE):
break;
case R_TYPE(REL32):
/* 32-bit PC-relative reference */
def = obj->symtab + symnum;
if (symnum >= obj->gotsym) {
tmp = load_ptr(where);
tmp += got[obj->local_gotno + symnum - obj->gotsym];
store_ptr(where, tmp);
rdbg(("REL32/G %s in %s --> %p in %s",
obj->strtab + def->st_name, obj->path,
(void *)tmp, obj->path));
break;
} else {
/*
* XXX: ABI DIFFERENCE!
*
* Old NetBSD binutils would generate shared
* libs with section-relative relocations being
* already adjusted for the start address of
* the section.
*
* New binutils, OTOH, generate shared libs
* with the same relocations being based at
* zero, so we need to add in the start address
* of the section.
*
* --rkb, Oct 6, 2001
*/
tmp = load_ptr(where);
if (def->st_info ==
ELF_ST_INFO(STB_LOCAL, STT_SECTION)
#ifdef SUPPORT_OLD_BROKEN_LD
&& !broken
#endif
)
tmp += (Elf_Addr)def->st_value;
tmp += (Elf_Addr)obj->relocbase;
store_ptr(where, tmp);
rdbg(("REL32/L %s in %s --> %p in %s",
obj->strtab + def->st_name, obj->path,
(void *)tmp, obj->path));
}
break;
default:
rdbg(("sym = %lu, type = %lu, offset = %p, "
"contents = %p, symbol = %s",
symnum, (u_long)ELF_R_TYPE(rel->r_info),
(void *)rel->r_offset, (void *)load_ptr(where),
obj->strtab + obj->symtab[symnum].st_name));
_rtld_error("%s: Unsupported relocation type %ld "
"in non-PLT relocations\n",
obj->path, (u_long) ELF_R_TYPE(rel->r_info));
return -1;
}
}
return 0;
}
int
_rtld_relocate_plt_lazy(const Obj_Entry *obj)
{
/* PLT fixups were done above in the GOT relocation. */
return 0;
}
static inline int
_rtld_relocate_plt_object(const Obj_Entry *obj, Elf_Word sym, Elf_Addr *tp)
{
Elf_Addr *got = obj->pltgot;
const Elf_Sym *def;
const Obj_Entry *defobj;
Elf_Addr new_value;
def = _rtld_find_symdef(sym, obj, &defobj, true);
if (def == NULL)
return -1;
new_value = (Elf_Addr)(defobj->relocbase + def->st_value);
rdbg(("bind now/fixup in %s --> new=%p",
defobj->strtab + def->st_name, (void *)new_value));
got[obj->local_gotno + sym - obj->gotsym] = new_value;
if (tp)
*tp = new_value;
return 0;
}
caddr_t
_rtld_bind(Elf_Word a0, Elf_Addr a1, Elf_Addr a2, Elf_Addr a3)
{
Elf_Addr *got = (Elf_Addr *)(a2 - 0x7ff0);
const Obj_Entry *obj = (Obj_Entry *)(got[1] & 0x7fffffff);
Elf_Addr new_value;
int err;
err = _rtld_relocate_plt_object(obj, a0, &new_value);
if (err || new_value == 0)
_rtld_die();
return (caddr_t)new_value;
}
int
_rtld_relocate_plt_objects(const Obj_Entry *obj)
{
const Elf_Sym *sym = obj->symtab + obj->gotsym;
int i;
for (i = obj->gotsym; i < obj->symtabno; i++, sym++) {
if (ELF_ST_TYPE(sym->st_info) == STT_FUNC)
if (_rtld_relocate_plt_object(obj, i, NULL) < 0)
return -1;
}
return 0;
}