freebsd-skq/libexec/rtld-elf/powerpc/reloc.c
pfg fab328f17f 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

668 lines
16 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/atomic.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 = 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=%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 = 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_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;
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 = 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);
if (ld_bind_not)
goto out;
/*
* 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((int)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;
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);
}
}
out:
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
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, 8)
+ TLS_TP_OFFSET + TLS_TCB_SIZE);
/*
* XXX gcc seems to ignore 'tp = _tp;'
*/
__asm __volatile("mr 2,%0" :: "r"(tp));
}
void*
__tls_get_addr(tls_index* ti)
{
register Elf_Addr **tp;
char *p;
__asm __volatile("mr %0,2" : "=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);
}