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| Current File : //usr/src/libexec/rtld-elf/mips/reloc.c |
/* $NetBSD: mips_reloc.c,v 1.58 2010/01/14 11:57:06 skrll 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>
__FBSDID("$FreeBSD: release/9.1.0/libexec/rtld-elf/mips/reloc.c 233831 2012-04-03 08:54:35Z kib $");
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/endian.h>
#include <stdlib.h>
#include <string.h>
#include "debug.h"
#include "rtld.h"
#ifdef __mips_n64
#define GOT1_MASK 0x8000000000000000UL
#else
#define GOT1_MASK 0x80000000UL
#endif
void
init_pltgot(Obj_Entry *obj)
{
if (obj->pltgot != NULL) {
obj->pltgot[0] = (Elf_Addr) &_rtld_bind_start;
if (obj->pltgot[1] & 0x80000000)
obj->pltgot[1] = (Elf_Addr) obj | GOT1_MASK;
}
}
int
do_copy_relocations(Obj_Entry *dstobj)
{
/* Do nothing */
return 0;
}
void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr);
/*
* It is possible for the compiler to emit relocations for unaligned data.
* We handle this situation with these inlines.
*/
#ifdef __mips_n64
/*
* ELF64 MIPS encodes the relocs uniquely. The first 32-bits of info contain
* the symbol index. The top 32-bits contain three relocation types encoded
* in big-endian integer with first relocation in LSB. This means for little
* endian we have to byte swap that integer (r_type).
*/
#define Elf_Sxword Elf64_Sxword
#define ELF_R_NXTTYPE_64_P(r_type) ((((r_type) >> 8) & 0xff) == R_TYPE(64))
#if BYTE_ORDER == LITTLE_ENDIAN
#undef ELF_R_SYM
#undef ELF_R_TYPE
#define ELF_R_SYM(r_info) ((r_info) & 0xffffffff)
#define ELF_R_TYPE(r_info) bswap32((r_info) >> 32)
#endif
#else
#define ELF_R_NXTTYPE_64_P(r_type) (0)
#define Elf_Sxword Elf32_Sword
#endif
static __inline Elf_Sxword
load_ptr(void *where, size_t len)
{
Elf_Sxword val;
if (__predict_true(((uintptr_t)where & (len - 1)) == 0)) {
#ifdef __mips_n64
if (len == sizeof(Elf_Sxword))
return *(Elf_Sxword *)where;
#endif
return *(Elf_Sword *)where;
}
val = 0;
#if BYTE_ORDER == LITTLE_ENDIAN
(void)memcpy(&val, where, len);
#endif
#if BYTE_ORDER == BIG_ENDIAN
(void)memcpy((uint8_t *)((&val)+1) - len, where, len);
#endif
return (len == sizeof(Elf_Sxword)) ? val : (Elf_Sword)val;
}
static __inline void
store_ptr(void *where, Elf_Sxword val, size_t len)
{
if (__predict_true(((uintptr_t)where & (len - 1)) == 0)) {
#ifdef __mips_n64
if (len == sizeof(Elf_Sxword)) {
*(Elf_Sxword *)where = val;
return;
}
#endif
*(Elf_Sword *)where = val;
return;
}
#if BYTE_ORDER == LITTLE_ENDIAN
(void)memcpy(where, &val, len);
#endif
#if BYTE_ORDER == BIG_ENDIAN
(void)memcpy(where, (const uint8_t *)((&val)+1) - len, len);
#endif
}
void
_rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase)
{
const Elf_Rel *rel = 0, *rellim;
Elf_Addr relsz = 0;
const Elf_Sym *symtab = NULL, *sym;
Elf_Addr *where;
Elf_Addr *got = NULL;
Elf_Word local_gotno = 0, symtabno = 0, gotsym = 0;
size_t 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] & GOT1_MASK) ? 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++) {
Elf_Word r_symndx, r_type;
where = (void *)(relocbase + rel->r_offset);
r_symndx = ELF_R_SYM(rel->r_info);
r_type = ELF_R_TYPE(rel->r_info);
switch (r_type & 0xff) {
case R_TYPE(REL32): {
const size_t rlen =
ELF_R_NXTTYPE_64_P(r_type)
? sizeof(Elf_Sxword)
: sizeof(Elf_Sword);
Elf_Sxword old = load_ptr(where, rlen);
Elf_Sxword val = old;
#ifdef __mips_n64
assert(r_type == R_TYPE(REL32)
|| r_type == (R_TYPE(REL32)|(R_TYPE(64) << 8)));
#endif
assert(r_symndx < gotsym);
sym = symtab + r_symndx;
assert(ELF_ST_BIND(sym->st_info) == STB_LOCAL);
val += relocbase;
store_ptr(where, val, sizeof(Elf_Sword));
dbg("REL32/L(%p) %p -> %p in <self>",
where, (void *)old, (void *)val);
store_ptr(where, val, rlen);
break;
}
case R_TYPE(GPREL32):
case R_TYPE(NONE):
break;
default:
abort();
break;
}
}
}
Elf_Addr
_mips_rtld_bind(Obj_Entry *obj, Elf_Size reloff)
{
Elf_Addr *got = obj->pltgot;
const Elf_Sym *def;
const Obj_Entry *defobj;
Elf_Addr target;
def = find_symdef(reloff, obj, &defobj, SYMLOOK_IN_PLT, NULL,
NULL);
if (def == NULL)
_rtld_error("bind failed no symbol");
target = (Elf_Addr)(defobj->relocbase + def->st_value);
dbg("bind now/fixup at %s sym # %d in %s --> was=%p new=%p",
obj->path,
reloff, defobj->strtab + def->st_name,
(void *)got[obj->local_gotno + reloff - obj->gotsym],
(void *)target);
got[obj->local_gotno + reloff - obj->gotsym] = target;
return (Elf_Addr)target;
}
int
reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags,
RtldLockState *lockstate)
{
const Elf_Rel *rel;
const Elf_Rel *rellim;
Elf_Addr *got = obj->pltgot;
const Elf_Sym *sym, *def;
const Obj_Entry *defobj;
Elf_Word i;
#ifdef SUPPORT_OLD_BROKEN_LD
int broken;
#endif
/* The relocation for the dynamic loader has already been done. */
if (obj == obj_rtld)
return (0);
#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] & GOT1_MASK) ? 2 : 1;
/* Relocate the local GOT entries */
got += i;
dbg("got:%p for %d entries adding %x",
got, obj->local_gotno, (uint32_t)obj->relocbase);
for (; i < obj->local_gotno; i++) {
*got += (Elf_Addr)obj->relocbase;
got++;
}
sym = obj->symtab + obj->gotsym;
dbg("got:%p for %d entries",
got, obj->symtabno);
/* Now do the global GOT entries */
for (i = obj->gotsym; i < obj->symtabno; i++) {
dbg(" doing got %d sym %p (%s, %lx)", i - obj->gotsym, sym,
sym->st_name + obj->strtab, (u_long) *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 = find_symdef(i, obj, &defobj, flags, NULL,
lockstate);
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;
if ((Elf_Addr)(*got) == (Elf_Addr)obj->relocbase) {
dbg("Warning2, i:%d maps to relocbase address:%x",
i, (uint32_t)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;
if ((Elf_Addr)(*got) == (Elf_Addr)obj->relocbase) {
dbg("Warning3, i:%d maps to relocbase address:%x",
i, (uint32_t)obj->relocbase);
}
}
} else {
/* TODO: add cache here */
def = find_symdef(i, obj, &defobj, flags, NULL,
lockstate);
if (def == NULL) {
dbg("Warning4, cant find symbole %d", i);
return -1;
}
*got = def->st_value + (Elf_Addr)defobj->relocbase;
if ((Elf_Addr)(*got) == (Elf_Addr)obj->relocbase) {
dbg("Warning4, i:%d maps to relocbase address:%x",
i, (uint32_t)obj->relocbase);
dbg("via first obj symbol %s",
obj->strtab + obj->symtab[i].st_name);
dbg("found in obj %p:%s",
defobj, defobj->path);
}
}
dbg(" --> now %lx", (u_long) *got);
++sym;
++got;
}
got = obj->pltgot;
rellim = (const Elf_Rel *)((caddr_t)obj->rel + obj->relsize);
for (rel = obj->rel; rel < rellim; rel++) {
Elf_Word r_symndx, r_type;
void *where;
where = obj->relocbase + rel->r_offset;
r_symndx = ELF_R_SYM(rel->r_info);
r_type = ELF_R_TYPE(rel->r_info);
switch (r_type & 0xff) {
case R_TYPE(NONE):
break;
case R_TYPE(REL32): {
/* 32-bit PC-relative reference */
const size_t rlen =
ELF_R_NXTTYPE_64_P(r_type)
? sizeof(Elf_Sxword)
: sizeof(Elf_Sword);
Elf_Sxword old = load_ptr(where, rlen);
Elf_Sxword val = old;
def = obj->symtab + r_symndx;
if (r_symndx >= obj->gotsym) {
val += got[obj->local_gotno + r_symndx - obj->gotsym];
dbg("REL32/G(%p) %p --> %p (%s) in %s",
where, (void *)old, (void *)val,
obj->strtab + def->st_name,
obj->path);
} 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
*/
if (def->st_info ==
ELF_ST_INFO(STB_LOCAL, STT_SECTION)
#ifdef SUPPORT_OLD_BROKEN_LD
&& !broken
#endif
)
val += (Elf_Addr)def->st_value;
val += (Elf_Addr)obj->relocbase;
dbg("REL32/L(%p) %p -> %p (%s) in %s",
where, (void *)old, (void *)val,
obj->strtab + def->st_name, obj->path);
}
store_ptr(where, val, rlen);
break;
}
default:
dbg("sym = %lu, type = %lu, offset = %p, "
"contents = %p, symbol = %s",
(u_long)r_symndx, (u_long)ELF_R_TYPE(rel->r_info),
(void *)rel->r_offset,
(void *)load_ptr(where, sizeof(Elf_Sword)),
obj->strtab + obj->symtab[r_symndx].st_name);
_rtld_error("%s: Unsupported relocation type %ld "
"in non-PLT relocations",
obj->path, (u_long) ELF_R_TYPE(rel->r_info));
return -1;
}
}
return 0;
}
/*
* Process the PLT relocations.
*/
int
reloc_plt(Obj_Entry *obj)
{
#if 0
const Elf_Rel *rellim;
const Elf_Rel *rel;
dbg("reloc_plt obj:%p pltrel:%p sz:%d", obj, obj->pltrel, (int)obj->pltrelsize);
dbg("gottable %p num syms:%d", obj->pltgot, obj->symtabno );
dbg("*****************************************************");
rellim = (const Elf_Rel *)((char *)obj->pltrel +
obj->pltrelsize);
for (rel = obj->pltrel; rel < rellim; rel++) {
Elf_Addr *where;
where = (Elf_Addr *)(obj->relocbase + rel->r_offset);
*where += (Elf_Addr )obj->relocbase;
}
#endif
/* PLT fixups were done above in the GOT relocation. */
return (0);
}
/*
* LD_BIND_NOW was set - force relocation for all jump slots
*/
int
reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate)
{
/* Do nothing */
obj->jmpslots_done = true;
return (0);
}
int
reloc_iresolve(Obj_Entry *obj, struct Struct_RtldLockState *lockstate)
{
/* XXX not implemented */
return (0);
}
int
reloc_gnu_ifunc(Obj_Entry *obj, int flags,
struct Struct_RtldLockState *lockstate)
{
/* XXX not implemented */
return (0);
}
Elf_Addr
reloc_jmpslot(Elf_Addr *where, Elf_Addr target, const Obj_Entry *defobj,
const Obj_Entry *obj, const Elf_Rel *rel)
{
/* Do nothing */
return target;
}
void
allocate_initial_tls(Obj_Entry *objs)
{
}
void *
__tls_get_addr(tls_index* ti)
{
return (NULL);
}