NetBSD-5.0.2/libexec/ld.elf_so/arch/sparc/mdreloc.c
/* $NetBSD: mdreloc.c,v 1.41 2008/07/24 04:39:25 matt Exp $ */
/*-
* Copyright (c) 1999, 2002 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Paul Kranenburg and by Charles M. Hannum.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``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 FOUNDATION OR CONTRIBUTORS
* 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>
#ifndef lint
__RCSID("$NetBSD: mdreloc.c,v 1.41 2008/07/24 04:39:25 matt Exp $");
#endif /* not lint */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include "rtldenv.h"
#include "debug.h"
#include "rtld.h"
/*
* The following table holds for each relocation type:
* - the width in bits of the memory location the relocation
* applies to (not currently used)
* - the number of bits the relocation value must be shifted to the
* right (i.e. discard least significant bits) to fit into
* the appropriate field in the instruction word.
* - flags indicating whether
* * the relocation involves a symbol
* * the relocation is relative to the current position
* * the relocation is for a GOT entry
* * the relocation is relative to the load address
*
*/
#define _RF_S 0x80000000 /* Resolve symbol */
#define _RF_A 0x40000000 /* Use addend */
#define _RF_P 0x20000000 /* Location relative */
#define _RF_G 0x10000000 /* GOT offset */
#define _RF_B 0x08000000 /* Load address relative */
#define _RF_U 0x04000000 /* Unaligned */
#define _RF_SZ(s) (((s) & 0xff) << 8) /* memory target size */
#define _RF_RS(s) ( (s) & 0xff) /* right shift */
static const int reloc_target_flags[] = {
0, /* NONE */
_RF_S|_RF_A| _RF_SZ(8) | _RF_RS(0), /* RELOC_8 */
_RF_S|_RF_A| _RF_SZ(16) | _RF_RS(0), /* RELOC_16 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* RELOC_32 */
_RF_S|_RF_A|_RF_P| _RF_SZ(8) | _RF_RS(0), /* DISP_8 */
_RF_S|_RF_A|_RF_P| _RF_SZ(16) | _RF_RS(0), /* DISP_16 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* DISP_32 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_30 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_22 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HI22 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 22 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 13 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LO10 */
_RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT10 */
_RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT13 */
_RF_G| _RF_SZ(32) | _RF_RS(10), /* GOT22 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PC10 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC22 */
_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WPLT30 */
_RF_SZ(32) | _RF_RS(0), /* COPY */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* GLOB_DAT */
_RF_SZ(32) | _RF_RS(0), /* JMP_SLOT */
_RF_A| _RF_B| _RF_SZ(32) | _RF_RS(0), /* RELATIVE */
_RF_S|_RF_A| _RF_U| _RF_SZ(32) | _RF_RS(0), /* UA_32 */
};
#ifdef RTLD_DEBUG_RELOC
static const char *reloc_names[] = {
"NONE", "RELOC_8", "RELOC_16", "RELOC_32", "DISP_8",
"DISP_16", "DISP_32", "WDISP_30", "WDISP_22", "HI22",
"22", "13", "LO10", "GOT10", "GOT13",
"GOT22", "PC10", "PC22", "WPLT30", "COPY",
"GLOB_DAT", "JMP_SLOT", "RELATIVE", "UA_32"
};
#endif
#define RELOC_RESOLVE_SYMBOL(t) ((reloc_target_flags[t] & _RF_S) != 0)
#define RELOC_PC_RELATIVE(t) ((reloc_target_flags[t] & _RF_P) != 0)
#define RELOC_BASE_RELATIVE(t) ((reloc_target_flags[t] & _RF_B) != 0)
#define RELOC_UNALIGNED(t) ((reloc_target_flags[t] & _RF_U) != 0)
#define RELOC_USE_ADDEND(t) ((reloc_target_flags[t] & _RF_A) != 0)
#define RELOC_TARGET_SIZE(t) ((reloc_target_flags[t] >> 8) & 0xff)
#define RELOC_VALUE_RIGHTSHIFT(t) (reloc_target_flags[t] & 0xff)
static const int reloc_target_bitmask[] = {
#define _BM(x) (~(-(1ULL << (x))))
0, /* NONE */
_BM(8), _BM(16), _BM(32), /* RELOC_8, _16, _32 */
_BM(8), _BM(16), _BM(32), /* DISP8, DISP16, DISP32 */
_BM(30), _BM(22), /* WDISP30, WDISP22 */
_BM(22), _BM(22), /* HI22, _22 */
_BM(13), _BM(10), /* RELOC_13, _LO10 */
_BM(10), _BM(13), _BM(22), /* GOT10, GOT13, GOT22 */
_BM(10), _BM(22), /* _PC10, _PC22 */
_BM(30), 0, /* _WPLT30, _COPY */
-1, -1, -1, /* _GLOB_DAT, JMP_SLOT, _RELATIVE */
_BM(32) /* _UA32 */
#undef _BM
};
#define RELOC_VALUE_BITMASK(t) (reloc_target_bitmask[t])
void _rtld_bind_start(void);
void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr);
caddr_t _rtld_bind(const Obj_Entry *, Elf_Word);
static inline int _rtld_relocate_plt_object(const Obj_Entry *,
const Elf_Rela *, Elf_Addr *);
void
_rtld_setup_pltgot(const Obj_Entry *obj)
{
/*
* PLTGOT is the PLT on the sparc.
* The first entry holds the call the dynamic linker.
* We construct a `call' sequence that transfers
* to `_rtld_bind_start()'.
* The second entry holds the object identification.
* Note: each PLT entry is three words long.
*/
#define SAVE 0x9de3bfa0 /* i.e. `save %sp,-96,%sp' */
#define CALL 0x40000000
#define NOP 0x01000000
obj->pltgot[0] = SAVE;
obj->pltgot[1] = CALL |
((Elf_Addr) &_rtld_bind_start - (Elf_Addr) &obj->pltgot[1]) >> 2;
obj->pltgot[2] = NOP;
obj->pltgot[3] = (Elf_Addr) obj;
}
void
_rtld_relocate_nonplt_self(Elf_Dyn *dynp, Elf_Addr relocbase)
{
const Elf_Rela *rela = 0, *relalim;
Elf_Addr relasz = 0;
Elf_Addr *where;
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;
}
}
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);
}
}
int
_rtld_relocate_nonplt_objects(const Obj_Entry *obj)
{
const Elf_Rela *rela;
for (rela = obj->rela; rela < obj->relalim; rela++) {
Elf_Addr *where;
Elf_Word type, value, mask;
const Elf_Sym *def = NULL;
const Obj_Entry *defobj = NULL;
unsigned long symnum;
where = (Elf_Addr *) (obj->relocbase + rela->r_offset);
symnum = ELF_R_SYM(rela->r_info);
type = ELF_R_TYPE(rela->r_info);
if (type == R_TYPE(NONE))
continue;
/* We do JMP_SLOTs in _rtld_bind() below */
if (type == R_TYPE(JMP_SLOT))
continue;
/* COPY relocs are also handled elsewhere */
if (type == R_TYPE(COPY))
continue;
/*
* We use the fact that relocation types are an `enum'
* Note: R_SPARC_6 is currently numerically largest.
*/
if (type > R_TYPE(6))
return (-1);
value = rela->r_addend;
/*
* Handle relative relocs here, as an optimization.
*/
if (type == R_TYPE(RELATIVE)) {
*where += (Elf_Addr)(obj->relocbase + value);
rdbg(("RELATIVE in %s --> %p", obj->path,
(void *)*where));
continue;
}
if (RELOC_RESOLVE_SYMBOL(type)) {
/* Find the symbol */
def = _rtld_find_symdef(symnum, obj, &defobj, false);
if (def == NULL)
return (-1);
/* Add in the symbol's absolute address */
value += (Elf_Word)(defobj->relocbase + def->st_value);
}
if (RELOC_PC_RELATIVE(type)) {
value -= (Elf_Word)where;
}
if (RELOC_BASE_RELATIVE(type)) {
/*
* Note that even though sparcs use `Elf_rela'
* exclusively we still need the implicit memory addend
* in relocations referring to GOT entries.
* Undoubtedly, someone f*cked this up in the distant
* past, and now we're stuck with it in the name of
* compatibility for all eternity..
*
* In any case, the implicit and explicit should be
* mutually exclusive. We provide a check for that
* here.
*/
#define DIAGNOSTIC
#ifdef DIAGNOSTIC
if (value != 0 && *where != 0) {
xprintf("BASE_REL(%s): where=%p, *where 0x%x, "
"addend=0x%x, base %p\n",
obj->path, where, *where,
rela->r_addend, obj->relocbase);
}
#endif
value += (Elf_Word)(obj->relocbase + *where);
}
mask = RELOC_VALUE_BITMASK(type);
value >>= RELOC_VALUE_RIGHTSHIFT(type);
value &= mask;
if (RELOC_UNALIGNED(type)) {
/* Handle unaligned relocations. */
Elf_Addr tmp = 0;
char *ptr = (char *)where;
int i, size = RELOC_TARGET_SIZE(type)/8;
/* Read it in one byte at a time. */
for (i=0; i<size; i++)
tmp = (tmp << 8) | ptr[i];
tmp &= ~mask;
tmp |= value;
/* Write it back out. */
for (i=0; i<size; i++)
ptr[i] = ((tmp >> (8*i)) & 0xff);
#ifdef RTLD_DEBUG_RELOC
value = (Elf_Word)tmp;
#endif
} else {
*where &= ~mask;
*where |= value;
#ifdef RTLD_DEBUG_RELOC
value = (Elf_Word)*where;
#endif
}
#ifdef RTLD_DEBUG_RELOC
if (RELOC_RESOLVE_SYMBOL(type)) {
rdbg(("%s %s in %s --> %p in %s", reloc_names[type],
obj->strtab + obj->symtab[symnum].st_name,
obj->path, (void *)value, defobj->path));
} else {
rdbg(("%s in %s --> %p", reloc_names[type],
obj->path, (void *)value));
}
#endif
}
return (0);
}
int
_rtld_relocate_plt_lazy(const Obj_Entry *obj)
{
return (0);
}
caddr_t
_rtld_bind(const Obj_Entry *obj, Elf_Word reloff)
{
const Elf_Rela *rela = (const Elf_Rela *)((caddr_t)obj->pltrela + reloff);
Elf_Addr value;
int err;
value = 0; /* XXX gcc */
err = _rtld_relocate_plt_object(obj, rela, &value);
if (err || value == 0)
_rtld_die();
return (caddr_t)value;
}
int
_rtld_relocate_plt_objects(const Obj_Entry *obj)
{
const Elf_Rela *rela = obj->pltrela;
for (; rela < obj->pltrelalim; rela++)
if (_rtld_relocate_plt_object(obj, rela, NULL) < 0)
return -1;
return 0;
}
static inline int
_rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela, Elf_Addr *tp)
{
const Elf_Sym *def;
const Obj_Entry *defobj;
Elf_Word *where = (Elf_Addr *)(obj->relocbase + rela->r_offset);
Elf_Addr value;
/* Fully resolve procedure addresses now */
assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT));
def = _rtld_find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, true);
if (def == NULL)
return -1;
value = (Elf_Addr)(defobj->relocbase + def->st_value);
rdbg(("bind now/fixup in %s --> new=%p",
defobj->strtab + def->st_name, (void *)value));
/*
* At the PLT entry pointed at by `where', we now construct
* a direct transfer to the now fully resolved function
* address. The resulting code in the jump slot is:
*
* sethi %hi(roffset), %g1
* sethi %hi(addr), %g1
* jmp %g1+%lo(addr)
*
* We write the third instruction first, since that leaves the
* previous `b,a' at the second word in place. Hence the whole
* PLT slot can be atomically change to the new sequence by
* writing the `sethi' instruction at word 2.
*/
#define SETHI 0x03000000
#define JMP 0x81c06000
#define NOP 0x01000000
where[2] = JMP | (value & 0x000003ff);
where[1] = SETHI | ((value >> 10) & 0x003fffff);
__asm volatile("iflush %0+8" : : "r" (where));
__asm volatile("iflush %0+4" : : "r" (where));
if (tp)
*tp = value;
return 0;
}