freebsd-dev/libexec/rtld-elf/mips/reloc.c
Adrian Chadd b812fe4d6b [mips] add support for using the MIPS user register for TLS data.
This work, originally from Stacey Son, uses the MIPS UserReg for
reading the TLS data, and will fall back to the normal syscall path
when it isn't supported.

This code dynamically patches cpu_switch() to bypass the UserReg
instruction so to avoid generating a machine exception.

Thanks to sson for the original work, and to Dan Nelson for
bringing it to date and testing it on MIPS32 with me.

Tested:

* mips64 (sson)
* mips74k (dnelson_1901@yahoo.com) - AR9344 SoC, UserReg support
* mips24k (adrian) - AR9331 SoC, no UserReg support

Obtained from:	sson, dnelson_1901@yahoo.com
2016-08-07 01:29:55 +00:00

703 lines
18 KiB
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("$FreeBSD$");
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/endian.h>
#include <stdlib.h>
#include <string.h>
#include <inttypes.h>
#include <machine/sysarch.h>
#include <machine/tls.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 = NULL, *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_die();
target = (Elf_Addr)(defobj->relocbase + def->st_value);
dbg("bind now/fixup at %s sym # %jd in %s --> was=%p new=%p",
obj->path,
(intmax_t)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);
if ((flags & SYMLOOK_IFUNC) != 0)
/* XXX not implemented */
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 %p",
got, obj->local_gotno, 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:%p",
i, 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:%p",
i, obj->relocbase);
}
}
} else {
/* TODO: add cache here */
def = find_symdef(i, obj, &defobj, flags, NULL,
lockstate);
if (def == NULL) {
dbg("Warning4, can't 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:%p",
i, 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;
}
#ifdef __mips_n64
case R_TYPE(TLS_DTPMOD64):
#else
case R_TYPE(TLS_DTPMOD32):
#endif
{
const size_t rlen = sizeof(Elf_Addr);
Elf_Addr old = load_ptr(where, rlen);
Elf_Addr val = old;
def = find_symdef(r_symndx, obj, &defobj, flags, NULL,
lockstate);
if (def == NULL)
return -1;
val += (Elf_Addr)defobj->tlsindex;
store_ptr(where, val, rlen);
dbg("DTPMOD %s in %s %p --> %p in %s",
obj->strtab + obj->symtab[r_symndx].st_name,
obj->path, (void *)old, (void*)val, defobj->path);
break;
}
#ifdef __mips_n64
case R_TYPE(TLS_DTPREL64):
#else
case R_TYPE(TLS_DTPREL32):
#endif
{
const size_t rlen = sizeof(Elf_Addr);
Elf_Addr old = load_ptr(where, rlen);
Elf_Addr val = old;
def = find_symdef(r_symndx, obj, &defobj, flags, NULL,
lockstate);
if (def == NULL)
return -1;
if (!defobj->tls_done && allocate_tls_offset(obj))
return -1;
val += (Elf_Addr)def->st_value - TLS_DTP_OFFSET;
store_ptr(where, val, rlen);
dbg("DTPREL %s in %s %p --> %p in %s",
obj->strtab + obj->symtab[r_symndx].st_name,
obj->path, (void*)old, (void *)val, defobj->path);
break;
}
#ifdef __mips_n64
case R_TYPE(TLS_TPREL64):
#else
case R_TYPE(TLS_TPREL32):
#endif
{
const size_t rlen = sizeof(Elf_Addr);
Elf_Addr old = load_ptr(where, rlen);
Elf_Addr val = old;
def = find_symdef(r_symndx, obj, &defobj, flags, NULL,
lockstate);
if (def == NULL)
return -1;
if (!defobj->tls_done && allocate_tls_offset(obj))
return -1;
val += (Elf_Addr)(def->st_value + defobj->tlsoffset
- TLS_TP_OFFSET - TLS_TCB_SIZE);
store_ptr(where, val, rlen);
dbg("TPREL %s in %s %p --> %p in %s",
obj->strtab + obj->symtab[r_symndx].st_name,
obj->path, (void*)old, (void *)val, defobj->path);
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:%s", obj, obj->pltrel, (int)obj->pltrelsize);
dbg("gottable %p num syms:%s", 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)
{
char *tls;
/*
* 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;
tls = (char *) allocate_tls(objs, NULL, TLS_TCB_SIZE, 8);
sysarch(MIPS_SET_TLS, tls);
}
#ifdef __mips_n64
void *
_mips_get_tls(void)
{
uint64_t _rv;
__asm__ __volatile__ (
".set\tpush\n\t"
".set\tmips64r2\n\t"
"rdhwr\t%0, $29\n\t"
".set\tpop"
: "=v" (_rv));
/*
* XXXSS See 'git show c6be4f4d2d1b71c04de5d3bbb6933ce2dbcdb317'
*
* Remove the offset since this really a request to get the TLS
* pointer via sysarch() (in theory). Of course, this may go away
* once the TLS code is rewritten.
*/
_rv = _rv - TLS_TP_OFFSET - TLS_TCB_SIZE;
return (void *)_rv;
}
#else /* mips 32 */
void *
_mips_get_tls(void)
{
uint32_t _rv;
__asm__ __volatile__ (
".set\tpush\n\t"
".set\tmips32r2\n\t"
"rdhwr\t%0, $29\n\t"
".set\tpop"
: "=v" (_rv));
/*
* XXXSS See 'git show c6be4f4d2d1b71c04de5d3bbb6933ce2dbcdb317'
*
* Remove the offset since this really a request to get the TLS
* pointer via sysarch() (in theory). Of course, this may go away
* once the TLS code is rewritten.
*/
_rv = _rv - TLS_TP_OFFSET - TLS_TCB_SIZE;
return (void *)_rv;
}
#endif /* ! __mips_n64 */
void *
__tls_get_addr(tls_index* ti)
{
Elf_Addr** tls;
char *p;
#ifdef TLS_USE_SYSARCH
sysarch(MIPS_GET_TLS, &tls);
#else
tls = _mips_get_tls();
#endif
p = tls_get_addr_common(tls, ti->ti_module, ti->ti_offset + TLS_DTP_OFFSET);
return (p);
}