freebsd-nq/libexec/rtld-elf/powerpc64/reloc.c
Pedro F. Giffuni e6209940de libexec: adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

No functional change intended.
2017-11-27 15:25:02 +00:00

569 lines
14 KiB
C

/* $NetBSD: ppc_reloc.c,v 1.10 2001/09/10 06:09:41 mycroft Exp $ */
/*-
* SPDX-License-Identifier: BSD-2-Clause-NetBSD
*
* 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"
#if !defined(_CALL_ELF) || _CALL_ELF == 1
struct funcdesc {
Elf_Addr addr;
Elf_Addr toc;
Elf_Addr env;
};
#endif
/*
* 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 = globallist_next(dstobj); srcobj != NULL;
srcobj = globallist_next(srcobj)) {
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 = NULL, *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;
if ((flags & SYMLOOK_IFUNC) != 0)
/* XXX not implemented */
return (0);
/*
* 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);
long reloff;
reloff = rela - obj->pltrela;
dbg(" reloc_plt_object: where=%p,reloff=%lx,glink=%#lx", (void *)where,
reloff, obj->glink);
#if !defined(_CALL_ELF) || _CALL_ELF == 1
/* Glink code is 3 instructions after the first 32k, 2 before */
*where = (Elf_Addr)obj->glink + 32 +
8*((reloff < 0x8000) ? reloff : 0x8000) +
12*((reloff < 0x8000) ? 0 : (reloff - 0x8000));
#else
*where = (Elf_Addr)obj->glink + 4*reloff + 32;
#endif
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 (def == &sym_zero) {
/* Zero undefined weak symbols */
#if !defined(_CALL_ELF) || _CALL_ELF == 1
bzero(where, sizeof(struct funcdesc));
#else
*where = 0;
#endif
} 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)
{
/*
* At the PLT entry pointed at by `wherep', construct
* a direct transfer to the now fully resolved function
* address.
*/
#if !defined(_CALL_ELF) || _CALL_ELF == 1
dbg(" reloc_jmpslot: where=%p, target=%p (%#lx + %#lx)",
(void *)wherep, (void *)target, *(Elf_Addr *)target,
(Elf_Addr)defobj->relocbase);
if (ld_bind_not)
goto out;
/*
* For the trampoline, the second two elements of the function
* descriptor are unused, so we are fine replacing those at any time
* with the real ones with no thread safety implications. However, we
* need to make sure the main entry point pointer ([0]) is seen to be
* modified *after* the second two elements. This can't be done in
* general, since there are no barriers in the reading code, but put in
* some isyncs to at least make it a little better.
*/
memcpy(wherep, (void *)target, sizeof(struct funcdesc));
wherep[2] = ((Elf_Addr *)target)[2];
wherep[1] = ((Elf_Addr *)target)[1];
__asm __volatile ("isync" : : : "memory");
wherep[0] = ((Elf_Addr *)target)[0];
__asm __volatile ("isync" : : : "memory");
if (((struct funcdesc *)(wherep))->addr < (Elf_Addr)defobj->relocbase) {
/*
* It is possible (LD_BIND_NOW) that the function
* descriptor we are copying has not yet been relocated.
* If this happens, fix it. Don't worry about threading in
* this case since LD_BIND_NOW makes it irrelevant.
*/
((struct funcdesc *)(wherep))->addr +=
(Elf_Addr)defobj->relocbase;
((struct funcdesc *)(wherep))->toc +=
(Elf_Addr)defobj->relocbase;
}
out:
#else
dbg(" reloc_jmpslot: where=%p, target=%p", (void *)wherep,
(void *)target);
if (!ld_bind_not)
*wherep = target;
#endif
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)
{
Elf_Addr *pltcall;
pltcall = obj->pltgot;
if (pltcall == NULL) {
return;
}
#if defined(_CALL_ELF) && _CALL_ELF == 2
pltcall[0] = (Elf_Addr)&_rtld_bind_start;
pltcall[1] = (Elf_Addr)obj;
#else
memcpy(pltcall, _rtld_bind_start, sizeof(struct funcdesc));
pltcall[2] = (Elf_Addr)obj;
#endif
}
void
ifunc_init(Elf_Auxinfo aux_info[__min_size(AT_COUNT)] __unused)
{
}
void
allocate_initial_tls(Obj_Entry *list)
{
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);
__asm __volatile("mr 13,%0" :: "r"(tp));
}
void*
__tls_get_addr(tls_index* ti)
{
Elf_Addr **tp;
char *p;
__asm __volatile("mr %0,13" : "=r"(tp));
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);
}