freebsd-nq/libexec/rtld-elf/powerpc64/reloc.c

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/* $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.
*
* $FreeBSD$
*/
#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/md_var.h>
#include "debug.h"
#include "rtld.h"
struct funcdesc {
Elf_Addr addr;
Elf_Addr toc;
Elf_Addr env;
};
/*
* 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=%zd\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_PPC64_UADDR64: /* doubleword64 S + A */
case R_PPC64_ADDR64:
case R_PPC_GLOB_DAT:
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: /* doubleword64 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_PPC64_DTPMOD64:
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_PPC64_TPREL64:
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_PPC64_DTPREL64:
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 %ld"
" 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 bytes = obj->dynsymcount * sizeof(SymCache);
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 = mmap(NULL, bytes, PROT_READ|PROT_WRITE, MAP_ANON,
-1, 0);
if (cache == MAP_FAILED)
cache = NULL;
} 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)
munmap(cache, bytes);
/* 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_Addr *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
Elf_Addr *glink;
long reloff;
reloff = rela - obj->pltrela;
if (obj->priv == NULL)
obj->priv = xmalloc(obj->pltrelasize);
glink = obj->priv + reloff*sizeof(Elf_Addr)*2;
dbg(" reloc_plt_object: where=%p,reloff=%lx,glink=%p", (void *)where, reloff, glink);
memcpy(where, _rtld_bind_start, sizeof(struct funcdesc));
((struct funcdesc *)(where))->env = (Elf_Addr)glink;
*(glink++) = (Elf_Addr)obj;
*(glink++) = reloff*sizeof(Elf_Rela);
return (0);
}
/*
* Process the PLT relocations.
*/
int
reloc_plt(Obj_Entry *obj)
{
const Elf_Rela *relalim;
const Elf_Rela *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);
}
}
}
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
if (def == &sym_zero) {
/* Zero undefined weak symbols */
bzero(where, sizeof(struct funcdesc));
} else {
reloc_jmpslot(where, target, defobj, obj,
(const Elf_Rel *) rela);
}
}
obj->jmpslots_done = true;
return (0);
}
/*
* Update the value of a PLT jump slot.
*/
Elf_Addr
reloc_jmpslot(Elf_Addr *wherep, Elf_Addr target, const Obj_Entry *defobj,
const Obj_Entry *obj, const Elf_Rel *rel)
{
dbg(" reloc_jmpslot: where=%p, target=%p (%#lx + %#lx)",
(void *)wherep, (void *)target, *(Elf_Addr *)target,
(Elf_Addr)defobj->relocbase);
/*
* At the PLT entry pointed at by `wherep', construct
* a direct transfer to the now fully resolved function
* address.
*/
memcpy(wherep, (void *)target, sizeof(struct funcdesc));
if (((struct funcdesc *)(wherep))->addr < (Elf_Addr)defobj->relocbase) {
/*
* XXX: It is possible (e.g. LD_BIND_NOW) that the function
* descriptor we are copying has not yet been relocated.
* If this happens, fix it.
*/
((struct funcdesc *)(wherep))->addr +=
(Elf_Addr)defobj->relocbase;
((struct funcdesc *)(wherep))->toc +=
(Elf_Addr)defobj->relocbase;
}
__asm __volatile("dcbst 0,%0; sync" :: "r"(wherep) : "memory");
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);
}
void
init_pltgot(Obj_Entry *obj)
{
}
void
allocate_initial_tls(Obj_Entry *list)
{
register Elf_Addr **tp __asm__("r13");
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, 16)
+ 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__("r13");
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);
}