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| Current File : //usr/src/libexec/rtld-elf/powerpc/reloc.c |
/* $NetBSD: ppc_reloc.c,v 1.10 2001/09/10 06:09:41 mycroft Exp $ */
/*-
* Copyright (C) 1998 Tsubai Masanari
* 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.
*
* $FreeBSD: release/9.1.0/libexec/rtld-elf/powerpc/reloc.c 235396 2012-05-13 12:50:42Z kib $
*/
#include <sys/param.h>
#include <sys/mman.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <machine/cpu.h>
#include <machine/cpufunc.h>
#include <machine/md_var.h>
#include "debug.h"
#include "rtld.h"
#define _ppc_ha(x) ((((u_int32_t)(x) & 0x8000) ? \
((u_int32_t)(x) + 0x10000) : (u_int32_t)(x)) >> 16)
#define _ppc_la(x) ((u_int32_t)(x) & 0xffff)
#define min(a,b) (((a) < (b)) ? (a) : (b))
#define max(a,b) (((a) > (b)) ? (a) : (b))
#define PLT_EXTENDED_BEGIN (1 << 13)
#define JMPTAB_BASE(N) (18 + N*2 + ((N > PLT_EXTENDED_BEGIN) ? \
(N - PLT_EXTENDED_BEGIN)*2 : 0))
/*
* Process the R_PPC_COPY relocations
*/
int
do_copy_relocations(Obj_Entry *dstobj)
{
const Elf_Rela *relalim;
const Elf_Rela *rela;
/*
* COPY relocs are invalid outside of the main program
*/
assert(dstobj->mainprog);
relalim = (const Elf_Rela *) ((caddr_t) dstobj->rela +
dstobj->relasize);
for (rela = dstobj->rela; rela < relalim; rela++) {
void *dstaddr;
const Elf_Sym *dstsym;
const char *name;
size_t size;
const void *srcaddr;
const Elf_Sym *srcsym = NULL;
const Obj_Entry *srcobj, *defobj;
SymLook req;
int res;
if (ELF_R_TYPE(rela->r_info) != R_PPC_COPY) {
continue;
}
dstaddr = (void *) (dstobj->relocbase + rela->r_offset);
dstsym = dstobj->symtab + ELF_R_SYM(rela->r_info);
name = dstobj->strtab + dstsym->st_name;
size = dstsym->st_size;
symlook_init(&req, name);
req.ventry = fetch_ventry(dstobj, ELF_R_SYM(rela->r_info));
req.flags = SYMLOOK_EARLY;
for (srcobj = dstobj->next; srcobj != NULL;
srcobj = srcobj->next) {
res = symlook_obj(&req, srcobj);
if (res == 0) {
srcsym = req.sym_out;
defobj = req.defobj_out;
break;
}
}
if (srcobj == NULL) {
_rtld_error("Undefined symbol \"%s\" "
" referenced from COPY"
" relocation in %s", name, dstobj->path);
return (-1);
}
srcaddr = (const void *) (defobj->relocbase+srcsym->st_value);
memcpy(dstaddr, srcaddr, size);
dbg("copy_reloc: src=%p,dst=%p,size=%d\n",srcaddr,dstaddr,size);
}
return (0);
}
/*
* Perform early relocation of the run-time linker image
*/
void
reloc_non_plt_self(Elf_Dyn *dynp, Elf_Addr relocbase)
{
const Elf_Rela *rela = 0, *relalim;
Elf_Addr relasz = 0;
Elf_Addr *where;
/*
* Extract the rela/relasz values from the dynamic section
*/
for (; dynp->d_tag != DT_NULL; dynp++) {
switch (dynp->d_tag) {
case DT_RELA:
rela = (const Elf_Rela *)(relocbase+dynp->d_un.d_ptr);
break;
case DT_RELASZ:
relasz = dynp->d_un.d_val;
break;
}
}
/*
* Relocate these values
*/
relalim = (const Elf_Rela *)((caddr_t)rela + relasz);
for (; rela < relalim; rela++) {
where = (Elf_Addr *)(relocbase + rela->r_offset);
*where = (Elf_Addr)(relocbase + rela->r_addend);
}
}
/*
* Relocate a non-PLT object with addend.
*/
static int
reloc_nonplt_object(Obj_Entry *obj_rtld, Obj_Entry *obj, const Elf_Rela *rela,
SymCache *cache, int flags, RtldLockState *lockstate)
{
Elf_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
const Elf_Sym *def;
const Obj_Entry *defobj;
Elf_Addr tmp;
switch (ELF_R_TYPE(rela->r_info)) {
case R_PPC_NONE:
break;
case R_PPC_ADDR32: /* word32 S + A */
case R_PPC_GLOB_DAT: /* word32 S + A */
def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
flags, cache, lockstate);
if (def == NULL) {
return (-1);
}
tmp = (Elf_Addr)(defobj->relocbase + def->st_value +
rela->r_addend);
/* Don't issue write if unnecessary; avoid COW page fault */
if (*where != tmp) {
*where = tmp;
}
break;
case R_PPC_RELATIVE: /* word32 B + A */
tmp = (Elf_Addr)(obj->relocbase + rela->r_addend);
/* As above, don't issue write unnecessarily */
if (*where != tmp) {
*where = tmp;
}
break;
case R_PPC_COPY:
/*
* These are deferred until all other relocations
* have been done. All we do here is make sure
* that the COPY relocation is not in a shared
* library. They are allowed only in executable
* files.
*/
if (!obj->mainprog) {
_rtld_error("%s: Unexpected R_COPY "
" relocation in shared library",
obj->path);
return (-1);
}
break;
case R_PPC_JMP_SLOT:
/*
* These will be handled by the plt/jmpslot routines
*/
break;
case R_PPC_DTPMOD32:
def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
flags, cache, lockstate);
if (def == NULL)
return (-1);
*where = (Elf_Addr) defobj->tlsindex;
break;
case R_PPC_TPREL32:
def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
flags, cache, lockstate);
if (def == NULL)
return (-1);
/*
* We lazily allocate offsets for static TLS as we
* see the first relocation that references the
* TLS block. This allows us to support (small
* amounts of) static TLS in dynamically loaded
* modules. If we run out of space, we generate an
* error.
*/
if (!defobj->tls_done) {
if (!allocate_tls_offset((Obj_Entry*) defobj)) {
_rtld_error("%s: No space available for static "
"Thread Local Storage", obj->path);
return (-1);
}
}
*(Elf_Addr **)where = *where * sizeof(Elf_Addr)
+ (Elf_Addr *)(def->st_value + rela->r_addend
+ defobj->tlsoffset - TLS_TP_OFFSET);
break;
case R_PPC_DTPREL32:
def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
flags, cache, lockstate);
if (def == NULL)
return (-1);
*where += (Elf_Addr)(def->st_value + rela->r_addend
- TLS_DTV_OFFSET);
break;
default:
_rtld_error("%s: Unsupported relocation type %d"
" in non-PLT relocations\n", obj->path,
ELF_R_TYPE(rela->r_info));
return (-1);
}
return (0);
}
/*
* Process non-PLT relocations
*/
int
reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags,
RtldLockState *lockstate)
{
const Elf_Rela *relalim;
const Elf_Rela *rela;
SymCache *cache;
int r = -1;
/*
* The dynamic loader may be called from a thread, we have
* limited amounts of stack available so we cannot use alloca().
*/
if (obj != obj_rtld) {
cache = calloc(obj->dynsymcount, sizeof(SymCache));
/* No need to check for NULL here */
} else
cache = NULL;
/*
* From the SVR4 PPC ABI:
* "The PowerPC family uses only the Elf32_Rela relocation
* entries with explicit addends."
*/
relalim = (const Elf_Rela *)((caddr_t)obj->rela + obj->relasize);
for (rela = obj->rela; rela < relalim; rela++) {
if (reloc_nonplt_object(obj_rtld, obj, rela, cache, flags,
lockstate) < 0)
goto done;
}
r = 0;
done:
if (cache != NULL)
free(cache);
/* Synchronize icache for text seg in case we made any changes */
__syncicache(obj->mapbase, obj->textsize);
return (r);
}
/*
* Initialise a PLT slot to the resolving trampoline
*/
static int
reloc_plt_object(Obj_Entry *obj, const Elf_Rela *rela)
{
Elf_Word *where = (Elf_Word *)(obj->relocbase + rela->r_offset);
Elf_Addr *pltresolve, *pltlongresolve, *jmptab;
Elf_Addr distance;
int N = obj->pltrelasize / sizeof(Elf_Rela);
int reloff;
reloff = rela - obj->pltrela;
if (reloff < 0)
return (-1);
pltlongresolve = obj->pltgot + 5;
pltresolve = pltlongresolve + 5;
distance = (Elf_Addr)pltresolve - (Elf_Addr)(where + 1);
dbg(" reloc_plt_object: where=%p,pltres=%p,reloff=%x,distance=%x",
(void *)where, (void *)pltresolve, reloff, distance);
if (reloff < PLT_EXTENDED_BEGIN) {
/* li r11,reloff */
/* b pltresolve */
where[0] = 0x39600000 | reloff;
where[1] = 0x48000000 | (distance & 0x03fffffc);
} else {
jmptab = obj->pltgot + JMPTAB_BASE(N);
jmptab[reloff] = (u_int)pltlongresolve;
/* lis r11,jmptab[reloff]@ha */
/* lwzu r12,jmptab[reloff]@l(r11) */
/* mtctr r12 */
/* bctr */
where[0] = 0x3d600000 | _ppc_ha(&jmptab[reloff]);
where[1] = 0x858b0000 | _ppc_la(&jmptab[reloff]);
where[2] = 0x7d8903a6;
where[3] = 0x4e800420;
}
/*
* The icache will be sync'd in reloc_plt, which is called
* after all the slots have been updated
*/
return (0);
}
/*
* Process the PLT relocations.
*/
int
reloc_plt(Obj_Entry *obj)
{
const Elf_Rela *relalim;
const Elf_Rela *rela;
int N = obj->pltrelasize / sizeof(Elf_Rela);
if (obj->pltrelasize != 0) {
relalim = (const Elf_Rela *)((char *)obj->pltrela +
obj->pltrelasize);
for (rela = obj->pltrela; rela < relalim; rela++) {
assert(ELF_R_TYPE(rela->r_info) == R_PPC_JMP_SLOT);
if (reloc_plt_object(obj, rela) < 0) {
return (-1);
}
}
}
/*
* Sync the icache for the byte range represented by the
* trampoline routines and call slots.
*/
if (obj->pltgot != NULL)
__syncicache(obj->pltgot, JMPTAB_BASE(N)*4);
return (0);
}
/*
* LD_BIND_NOW was set - force relocation for all jump slots
*/
int
reloc_jmpslots(Obj_Entry *obj, int flags, RtldLockState *lockstate)
{
const Obj_Entry *defobj;
const Elf_Rela *relalim;
const Elf_Rela *rela;
const Elf_Sym *def;
Elf_Addr *where;
Elf_Addr target;
relalim = (const Elf_Rela *)((char *)obj->pltrela + obj->pltrelasize);
for (rela = obj->pltrela; rela < relalim; rela++) {
assert(ELF_R_TYPE(rela->r_info) == R_PPC_JMP_SLOT);
where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj,
SYMLOOK_IN_PLT | flags, NULL, lockstate);
if (def == NULL) {
dbg("reloc_jmpslots: sym not found");
return (-1);
}
target = (Elf_Addr)(defobj->relocbase + def->st_value);
#if 0
/* PG XXX */
dbg("\"%s\" in \"%s\" --> %p in \"%s\"",
defobj->strtab + def->st_name, basename(obj->path),
(void *)target, basename(defobj->path));
#endif
reloc_jmpslot(where, target, defobj, obj,
(const Elf_Rel *) rela);
}
obj->jmpslots_done = true;
return (0);
}
/*
* Update the value of a PLT jump slot. Branch directly to the target if
* it is within +/- 32Mb, otherwise go indirectly via the pltcall
* trampoline call and jump table.
*/
Elf_Addr
reloc_jmpslot(Elf_Addr *wherep, Elf_Addr target, const Obj_Entry *defobj,
const Obj_Entry *obj, const Elf_Rel *rel)
{
Elf_Addr offset;
const Elf_Rela *rela = (const Elf_Rela *) rel;
dbg(" reloc_jmpslot: where=%p, target=%p",
(void *)wherep, (void *)target);
/*
* At the PLT entry pointed at by `wherep', construct
* a direct transfer to the now fully resolved function
* address.
*/
offset = target - (Elf_Addr)wherep;
if (abs(offset) < 32*1024*1024) { /* inside 32MB? */
/* b value # branch directly */
*wherep = 0x48000000 | (offset & 0x03fffffc);
__syncicache(wherep, 4);
} else {
Elf_Addr *pltcall, *jmptab;
int distance;
int N = obj->pltrelasize / sizeof(Elf_Rela);
int reloff = rela - obj->pltrela;
if (reloff < 0)
return (-1);
pltcall = obj->pltgot;
dbg(" reloc_jmpslot: indir, reloff=%x, N=%x\n",
reloff, N);
jmptab = obj->pltgot + JMPTAB_BASE(N);
jmptab[reloff] = target;
powerpc_mb(); /* Order jmptab update before next changes */
if (reloff < PLT_EXTENDED_BEGIN) {
/* for extended PLT entries, we keep the old code */
distance = (Elf_Addr)pltcall - (Elf_Addr)(wherep + 1);
/* li r11,reloff */
/* b pltcall # use indirect pltcall routine */
/* first instruction same as before */
wherep[1] = 0x48000000 | (distance & 0x03fffffc);
__syncicache(wherep, 8);
}
}
return (target);
}
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);
}
/*
* Setup the plt glue routines.
*/
#define PLTCALL_SIZE 20
#define PLTLONGRESOLVE_SIZE 20
#define PLTRESOLVE_SIZE 24
void
init_pltgot(Obj_Entry *obj)
{
Elf_Word *pltcall, *pltresolve, *pltlongresolve;
Elf_Word *jmptab;
int N = obj->pltrelasize / sizeof(Elf_Rela);
pltcall = obj->pltgot;
if (pltcall == NULL) {
return;
}
/*
* From the SVR4 PPC ABI:
*
* 'The first 18 words (72 bytes) of the PLT are reserved for
* use by the dynamic linker.
* ...
* 'If the executable or shared object requires N procedure
* linkage table entries, the link editor shall reserve 3*N
* words (12*N bytes) following the 18 reserved words. The
* first 2*N of these words are the procedure linkage table
* entries themselves. The static linker directs calls to bytes
* (72 + (i-1)*8), for i between 1 and N inclusive. The remaining
* N words (4*N bytes) are reserved for use by the dynamic linker.'
*/
/*
* Copy the absolute-call assembler stub into the first part of
* the reserved PLT area.
*/
memcpy(pltcall, _rtld_powerpc_pltcall, PLTCALL_SIZE);
/*
* Determine the address of the jumptable, which is the dyn-linker
* reserved area after the call cells. Write the absolute address
* of the jumptable into the absolute-call assembler code so it
* can determine this address.
*/
jmptab = obj->pltgot + JMPTAB_BASE(N);
pltcall[1] |= _ppc_ha(jmptab); /* addis 11,11,jmptab@ha */
pltcall[2] |= _ppc_la(jmptab); /* lwz 11,jmptab@l(11) */
/*
* Skip down 20 bytes into the initial reserved area and copy
* in the standard resolving assembler call. Into this assembler,
* insert the absolute address of the _rtld_bind_start routine
* and the address of the relocation object.
*
* We place pltlongresolve first, so it can fix up its arguments
* and then fall through to the regular PLT resolver.
*/
pltlongresolve = obj->pltgot + 5;
memcpy(pltlongresolve, _rtld_powerpc_pltlongresolve,
PLTLONGRESOLVE_SIZE);
pltlongresolve[0] |= _ppc_ha(jmptab); /* lis 12,jmptab@ha */
pltlongresolve[1] |= _ppc_la(jmptab); /* addi 12,12,jmptab@l */
pltresolve = pltlongresolve + PLTLONGRESOLVE_SIZE/sizeof(uint32_t);
memcpy(pltresolve, _rtld_powerpc_pltresolve, PLTRESOLVE_SIZE);
pltresolve[0] |= _ppc_ha(_rtld_bind_start);
pltresolve[1] |= _ppc_la(_rtld_bind_start);
pltresolve[3] |= _ppc_ha(obj);
pltresolve[4] |= _ppc_la(obj);
/*
* The icache will be sync'd in reloc_plt, which is called
* after all the slots have been updated
*/
}
void
allocate_initial_tls(Obj_Entry *list)
{
register Elf_Addr **tp __asm__("r2");
Elf_Addr **_tp;
/*
* Fix the size of the static TLS block by using the maximum
* offset allocated so far and adding a bit for dynamic modules to
* use.
*/
tls_static_space = tls_last_offset + tls_last_size + RTLD_STATIC_TLS_EXTRA;
_tp = (Elf_Addr **) ((char *) allocate_tls(list, NULL, TLS_TCB_SIZE, 8)
+ TLS_TP_OFFSET + TLS_TCB_SIZE);
/*
* XXX gcc seems to ignore 'tp = _tp;'
*/
__asm __volatile("mr %0,%1" : "=r"(tp) : "r"(_tp));
}
void*
__tls_get_addr(tls_index* ti)
{
register Elf_Addr **tp __asm__("r2");
char *p;
p = tls_get_addr_common((Elf_Addr**)((Elf_Addr)tp - TLS_TP_OFFSET
- TLS_TCB_SIZE), ti->ti_module, ti->ti_offset);
return (p + TLS_DTV_OFFSET);
}