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minix/libexec/ld.elf_so/arch/sparc64/mdreloc.c
Lionel Sambuc 84d9c625bf Synchronize on NetBSD-CVS (2013/12/1 12:00:00 UTC) 
- Fix for possible unset uid/gid in toproto
 - Fix for default mtree style
 - Update libelf
 - Importing libexecinfo
 - Resynchronize GCC, mpc, gmp, mpfr
 - build.sh: Replace params with show-params.
     This has been done as the make target has been renamed in the same
     way, while a new target named params has been added. This new
     target generates a file containing all the parameters, instead of
     printing it on the console.
 - Update test48 with new etc/services (Fix by Ben Gras <ben@minix3.org)
     get getservbyport() out of the inner loop

Change-Id: Ie6ad5226fa2621ff9f0dee8782ea48f9443d2091
2014-07-28 17:05:06 +02:00

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/* $NetBSD: mdreloc.c,v 1.55 2013/10/03 10:45:57 martin Exp $ */
/*-
* Copyright (c) 2000 Eduardo Horvath.
* 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 1.55 2013/10/03 10:45:57 martin Exp $");
#endif /* not lint */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.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[R_TYPE(TLS_TPOFF64)+1] = {
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(64) | _RF_RS(0), /* GLOB_DAT */
_RF_SZ(32) | _RF_RS(0), /* JMP_SLOT */
_RF_A| _RF_B| _RF_SZ(64) | _RF_RS(0), /* RELATIVE */
_RF_S|_RF_A| _RF_U| _RF_SZ(32) | _RF_RS(0), /* UA_32 */
_RF_A| _RF_SZ(32) | _RF_RS(0), /* PLT32 */
_RF_A| _RF_SZ(32) | _RF_RS(10), /* HIPLT22 */
_RF_A| _RF_SZ(32) | _RF_RS(0), /* LOPLT10 */
_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PCPLT32 */
_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PCPLT22 */
_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PCPLT10 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 10 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 11 */
_RF_S|_RF_A| _RF_SZ(64) | _RF_RS(0), /* 64 */
_RF_S|_RF_A|/*extra*/ _RF_SZ(32) | _RF_RS(0), /* OLO10 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(42), /* HH22 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(32), /* HM10 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* LM22 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(42), /* PC_HH22 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(32), /* PC_HM10 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC_LM22 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP16 */
_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP19 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* GLOB_JMP */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 7 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 5 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 6 */
_RF_S|_RF_A|_RF_P| _RF_SZ(64) | _RF_RS(0), /* DISP64 */
_RF_A| _RF_SZ(64) | _RF_RS(0), /* PLT64 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HIX22 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LOX10 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(22), /* H44 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(12), /* M44 */
_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* L44 */
_RF_S|_RF_A| _RF_SZ(64) | _RF_RS(0), /* REGISTER */
_RF_S|_RF_A| _RF_U| _RF_SZ(64) | _RF_RS(0), /* UA64 */
_RF_S|_RF_A| _RF_U| _RF_SZ(16) | _RF_RS(0), /* UA16 */
/* TLS relocs not represented here! */
};
#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", "PLT32",
"HIPLT22", "LOPLT10", "LOPLT10", "PCPLT22", "PCPLT32",
"10", "11", "64", "OLO10", "HH22",
"HM10", "LM22", "PC_HH22", "PC_HM10", "PC_LM22",
"WDISP16", "WDISP19", "GLOB_JMP", "7", "5", "6",
"DISP64", "PLT64", "HIX22", "LOX10", "H44", "M44",
"L44", "REGISTER", "UA64", "UA16",
"TLS_GD_HI22", "TLS_GD_LO10", "TLS_GD_ADD", "TLS_GD_CALL",
"TLS_LDM_HI22", "TLS_LDM_LO10", "TLS_LDM_ADD", "TLS_LDM_CALL",
"TLS_LDO_HIX22", "TLS_LDO_LOX10", "TLS_LDO_ADD", "TLS_IE_HI22",
"TLS_IE_LO10", "TLS_IE_LD", "TLS_IE_LDX", "TLS_IE_ADD", "TLS_LE_HIX22",
"TLS_LE_LOX10", "TLS_DTPMOD32", "TLS_DTPMOD64", "TLS_DTPOFF32",
"TLS_DTPOFF64", "TLS_TPOFF32", "TLS_TPOFF64",
};
#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)
#define RELOC_TLS(t) (t >= R_TYPE(TLS_GD_HI22))
static const long 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 */
_BM(32), _BM(32), _BM(32), /* _GLOB_DAT, JMP_SLOT, _RELATIVE */
_BM(32), _BM(32), /* _UA32, PLT32 */
_BM(22), _BM(10), /* _HIPLT22, LOPLT10 */
_BM(32), _BM(22), _BM(10), /* _PCPLT32, _PCPLT22, _PCPLT10 */
_BM(10), _BM(11), -1, /* _10, _11, _64 */
_BM(10), _BM(22), /* _OLO10, _HH22 */
_BM(10), _BM(22), /* _HM10, _LM22 */
_BM(22), _BM(10), _BM(22), /* _PC_HH22, _PC_HM10, _PC_LM22 */
_BM(16), _BM(19), /* _WDISP16, _WDISP19 */
-1, /* GLOB_JMP */
_BM(7), _BM(5), _BM(6), /* _7, _5, _6 */
-1, -1, /* DISP64, PLT64 */
_BM(22), _BM(13), /* HIX22, LOX10 */
_BM(22), _BM(10), _BM(12), /* H44, M44, L44 */
-1, -1, _BM(16), /* REGISTER, UA64, UA16 */
#undef _BM
};
#define RELOC_VALUE_BITMASK(t) (reloc_target_bitmask[t])
/*
* Instruction templates:
*/
#define BAA 0x10400000 /* ba,a %xcc, 0 */
#define SETHI 0x03000000 /* sethi %hi(0), %g1 */
#define JMP 0x81c06000 /* jmpl %g1+%lo(0), %g0 */
#define NOP 0x01000000 /* sethi %hi(0), %g0 */
#define OR 0x82806000 /* or %g1, 0, %g1 */
#define XOR 0x82c06000 /* xor %g1, 0, %g1 */
#define MOV71 0x8283a000 /* or %o7, 0, %g1 */
#define MOV17 0x9c806000 /* or %g1, 0, %o7 */
#define CALL 0x40000000 /* call 0 */
#define SLLX 0x8b407000 /* sllx %g1, 0, %g1 */
#define SETHIG5 0x0b000000 /* sethi %hi(0), %g5 */
#define ORG5 0x82804005 /* or %g1, %g5, %g1 */
/* %hi(v)/%lo(v) with variable shift */
#define HIVAL(v, s) (((v) >> (s)) & 0x003fffff)
#define LOVAL(v, s) (((v) >> (s)) & 0x000003ff)
void _rtld_bind_start_0(long, long);
void _rtld_bind_start_1(long, long);
void _rtld_relocate_nonplt_self(Elf_Dyn *, Elf_Addr);
caddr_t _rtld_bind(const Obj_Entry *, Elf_Word);
/*
* Install rtld function call into this PLT slot.
*/
#define SAVE 0x9de3bf50 /* i.e. `save %sp,-176,%sp' */
#define SETHI_l0 0x21000000
#define SETHI_l1 0x23000000
#define OR_l0_l0 0xa0142000
#define SLLX_l0_32_l0 0xa12c3020
#define OR_l0_l1_l0 0xa0140011
#define JMPL_l0_o0 0x91c42000
#define MOV_g1_o1 0x92100001
void _rtld_install_plt(Elf_Word *, Elf_Addr);
static inline int _rtld_relocate_plt_object(const Obj_Entry *,
const Elf_Rela *, Elf_Addr *);
void
_rtld_install_plt(Elf_Word *pltgot, Elf_Addr proc)
{
pltgot[0] = SAVE;
pltgot[1] = SETHI_l0 | HIVAL(proc, 42);
pltgot[2] = SETHI_l1 | HIVAL(proc, 10);
pltgot[3] = OR_l0_l0 | LOVAL(proc, 32);
pltgot[4] = SLLX_l0_32_l0;
pltgot[5] = OR_l0_l1_l0;
pltgot[6] = JMPL_l0_o0 | LOVAL(proc, 0);
pltgot[7] = MOV_g1_o1;
}
void
_rtld_setup_pltgot(const Obj_Entry *obj)
{
/*
* On sparc64 we got troubles.
*
* Instructions are 4 bytes long.
* Elf[64]_Addr is 8 bytes long, so are our pltglot[]
* array entries.
* Each PLT entry jumps to PLT0 to enter the dynamic
* linker.
* Loading an arbitrary 64-bit pointer takes 6
* instructions and 2 registers.
*
* Somehow we need to issue a save to get a new stack
* frame, load the address of the dynamic linker, and
* jump there, in 8 instructions or less.
*
* Oh, we need to fill out both PLT0 and PLT1.
*/
{
Elf_Word *entry = (Elf_Word *)obj->pltgot;
/* Install in entries 0 and 1 */
_rtld_install_plt(&entry[0], (Elf_Addr) &_rtld_bind_start_0);
_rtld_install_plt(&entry[8], (Elf_Addr) &_rtld_bind_start_1);
/*
* Install the object reference in first slot
* of entry 2.
*/
obj->pltgot[8] = (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 *)((const uint8_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(Obj_Entry *obj)
{
const Elf_Rela *rela;
const Elf_Sym *def = NULL;
const Obj_Entry *defobj = NULL;
for (rela = obj->rela; rela < obj->relalim; rela++) {
Elf_Addr *where;
Elf_Word type;
Elf_Addr value = 0, mask;
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;
/* OLO10 relocations have extra info */
if ((type & 0x00ff) == R_SPARC_OLO10)
type = R_SPARC_OLO10;
/* 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_TLS_TPOFF64 is currently numerically largest.
*/
if (type > R_TYPE(TLS_TPOFF64)) {
dbg(("unknown relocation type %x at %p", type, rela));
return -1;
}
value = rela->r_addend;
/*
* Handle TLS relocations here, they are different.
*/
if (RELOC_TLS(type)) {
switch (type) {
case R_TYPE(TLS_DTPMOD64):
def = _rtld_find_symdef(symnum, obj,
&defobj, false);
if (def == NULL)
return -1;
*where = (Elf64_Addr)defobj->tlsindex;
rdbg(("TLS_DTPMOD64 %s in %s --> %p",
obj->strtab +
obj->symtab[symnum].st_name,
obj->path, (void *)*where));
break;
case R_TYPE(TLS_DTPOFF64):
def = _rtld_find_symdef(symnum, obj,
&defobj, false);
if (def == NULL)
return -1;
*where = (Elf64_Addr)(def->st_value
+ rela->r_addend);
rdbg(("DTPOFF64 %s in %s --> %p",
obj->strtab +
obj->symtab[symnum].st_name,
obj->path, (void *)*where));
break;
case R_TYPE(TLS_TPOFF64):
def = _rtld_find_symdef(symnum, obj,
&defobj, false);
if (def == NULL)
return -1;
if (!defobj->tls_done &&
_rtld_tls_offset_allocate(obj))
return -1;
*where = (Elf64_Addr)(def->st_value -
defobj->tlsoffset +
rela->r_addend);
rdbg(("TLS_TPOFF64 %s in %s --> %p",
obj->strtab +
obj->symtab[symnum].st_name,
obj->path, (void *)*where));
break;
}
continue;
}
/*
* 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_Addr)(defobj->relocbase + def->st_value);
}
if (type == R_SPARC_OLO10) {
value = (value & 0x3ff)
+ (((Elf64_Xword)rela->r_info<<32)>>40);
}
if (RELOC_PC_RELATIVE(type)) {
value -= (Elf_Addr)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.
*/
#ifdef DIAGNOSTIC
if (value != 0 && *where != 0) {
xprintf("BASE_REL(%s): where=%p, *where 0x%lx, "
"addend=0x%lx, base %p\n",
obj->path, where, *where,
rela->r_addend, obj->relocbase);
}
#endif
/* XXXX -- apparently we ignore the preexisting value */
value += (Elf_Addr)(obj->relocbase);
}
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_Addr)tmp;
#endif
} else if (RELOC_TARGET_SIZE(type) > 32) {
*where &= ~mask;
*where |= value;
#ifdef RTLD_DEBUG_RELOC
value = (Elf_Addr)*where;
#endif
} else {
Elf32_Addr *where32 = (Elf32_Addr *)where;
*where32 &= ~mask;
*where32 |= value;
#ifdef RTLD_DEBUG_RELOC
value = (Elf_Addr)*where32;
#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 = obj->pltrela + reloff;
Elf_Addr result;
int err;
result = 0; /* XXX gcc */
if (ELF_R_TYPE(obj->pltrela->r_info) == R_TYPE(JMP_SLOT)) {
/*
* XXXX
*
* The first four PLT entries are reserved. There is some
* disagreement whether they should have associated relocation
* entries. Both the SPARC 32-bit and 64-bit ELF
* specifications say that they should have relocation entries,
* but the 32-bit SPARC binutils do not generate them, and now
* the 64-bit SPARC binutils have stopped generating them too.
*
* So, to provide binary compatibility, we will check the first
* entry, if it is reserved it should not be of the type
* JMP_SLOT. If it is JMP_SLOT, then the 4 reserved entries
* were not generated and our index is 4 entries too far.
*/
rela -= 4;
}
_rtld_shared_enter();
err = _rtld_relocate_plt_object(obj, rela, &result);
if (err)
_rtld_die();
_rtld_shared_exit();
return (caddr_t)result;
}
int
_rtld_relocate_plt_objects(const Obj_Entry *obj)
{
const Elf_Rela *rela;
rela = obj->pltrela;
/*
* Check for first four reserved entries - and skip them.
* See above for details.
*/
if (ELF_R_TYPE(obj->pltrela->r_info) != R_TYPE(JMP_SLOT))
rela += 4;
for (; rela < obj->pltrelalim; rela++)
if (_rtld_relocate_plt_object(obj, rela, NULL) < 0)
return -1;
return 0;
}
/*
* New inline function that is called by _rtld_relocate_plt_object and
* _rtld_bind
*/
static inline int
_rtld_relocate_plt_object(const Obj_Entry *obj, const Elf_Rela *rela,
Elf_Addr *tp)
{
Elf_Word *where = (Elf_Word *)(obj->relocbase + rela->r_offset);
const Elf_Sym *def;
const Obj_Entry *defobj;
Elf_Addr value, offset;
unsigned long info = rela->r_info;
assert(ELF_R_TYPE(info) == R_TYPE(JMP_SLOT));
def = _rtld_find_plt_symdef(ELF_R_SYM(info), obj, &defobj, tp != NULL);
if (__predict_false(def == NULL))
return -1;
if (__predict_false(def == &_rtld_sym_zero))
return 0;
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.
*
* A PLT entry is supposed to start by looking like this:
*
* sethi %hi(. - .PLT0), %g1
* ba,a %xcc, .PLT1
* nop
* nop
* nop
* nop
* nop
* nop
*
* When we replace these entries we start from the last instruction
* and do it in reverse order so the last thing we do is replace the
* branch. That allows us to change this atomically.
*
* We now need to find out how far we need to jump. We have a choice
* of several different relocation techniques which are increasingly
* expensive.
*/
offset = ((Elf_Addr)where) - value;
if (rela->r_addend) {
Elf_Addr *ptr = (Elf_Addr *)where;
/*
* This entry is >= 32768. The relocations points to a
* PC-relative pointer to the bind_0 stub at the top of the
* PLT section. Update it to point to the target function.
*/
ptr[0] += value - (Elf_Addr)obj->pltgot;
} else if (offset <= (1L<<20) && (Elf_SOff)offset >= -(1L<<20)) {
/*
* We're within 1MB -- we can use a direct branch insn.
*
* We can generate this pattern:
*
* sethi %hi(. - .PLT0), %g1
* ba,a %xcc, addr
* nop
* nop
* nop
* nop
* nop
* nop
*
*/
where[1] = BAA | ((offset >> 2) & 0x3fffff);
__asm volatile("iflush %0+4" : : "r" (where));
} else if (value < (1L<<32)) {
/*
* We're within 32-bits of address zero.
*
* The resulting code in the jump slot is:
*
* sethi %hi(. - .PLT0), %g1
* sethi %hi(addr), %g1
* jmp %g1+%lo(addr)
* nop
* nop
* nop
* nop
* nop
*
*/
where[2] = JMP | LOVAL(value, 0);
where[1] = SETHI | HIVAL(value, 10);
__asm volatile("iflush %0+8" : : "r" (where));
__asm volatile("iflush %0+4" : : "r" (where));
} else if ((Elf_SOff)value <= 0 && (Elf_SOff)value > -(1L<<32)) {
/*
* We're within 32-bits of address -1.
*
* The resulting code in the jump slot is:
*
* sethi %hi(. - .PLT0), %g1
* sethi %hix(addr), %g1
* xor %g1, %lox(addr), %g1
* jmp %g1
* nop
* nop
* nop
* nop
*
*/
where[3] = JMP;
where[2] = XOR | ((~value) & 0x00001fff);
where[1] = SETHI | HIVAL(~value, 10);
__asm volatile("iflush %0+12" : : "r" (where));
__asm volatile("iflush %0+8" : : "r" (where));
__asm volatile("iflush %0+4" : : "r" (where));
} else if (offset <= (1L<<32) && (Elf_SOff)offset >= -((1L<<32) - 4)) {
/*
* We're within 32-bits -- we can use a direct call insn
*
* The resulting code in the jump slot is:
*
* sethi %hi(. - .PLT0), %g1
* mov %o7, %g1
* call (.+offset)
* mov %g1, %o7
* nop
* nop
* nop
* nop
*
*/
where[3] = MOV17;
where[2] = CALL | ((offset >> 4) & 0x3fffffff);
where[1] = MOV71;
__asm volatile("iflush %0+12" : : "r" (where));
__asm volatile("iflush %0+8" : : "r" (where));
__asm volatile("iflush %0+4" : : "r" (where));
} else if (offset < (1L<<44)) {
/*
* We're within 44 bits. We can generate this pattern:
*
* The resulting code in the jump slot is:
*
* sethi %hi(. - .PLT0), %g1
* sethi %h44(addr), %g1
* or %g1, %m44(addr), %g1
* sllx %g1, 12, %g1
* jmp %g1+%l44(addr)
* nop
* nop
* nop
*
*/
where[4] = JMP | LOVAL(offset, 0);
where[3] = SLLX | 12;
where[2] = OR | (((offset) >> 12) & 0x00001fff);
where[1] = SETHI | HIVAL(offset, 22);
__asm volatile("iflush %0+16" : : "r" (where));
__asm volatile("iflush %0+12" : : "r" (where));
__asm volatile("iflush %0+8" : : "r" (where));
__asm volatile("iflush %0+4" : : "r" (where));
} else if ((Elf_SOff)offset < 0 && (Elf_SOff)offset > -(1L<<44)) {
/*
* We're within 44 bits. We can generate this pattern:
*
* The resulting code in the jump slot is:
*
* sethi %hi(. - .PLT0), %g1
* sethi %h44(-addr), %g1
* xor %g1, %m44(-addr), %g1
* sllx %g1, 12, %g1
* jmp %g1+%l44(addr)
* nop
* nop
* nop
*
*/
where[4] = JMP | LOVAL(offset, 0);
where[3] = SLLX | 12;
where[2] = XOR | (((~offset) >> 12) & 0x00001fff);
where[1] = SETHI | HIVAL(~offset, 22);
__asm volatile("iflush %0+16" : : "r" (where));
__asm volatile("iflush %0+12" : : "r" (where));
__asm volatile("iflush %0+8" : : "r" (where));
__asm volatile("iflush %0+4" : : "r" (where));
} else {
/*
* We need to load all 64-bits
*
* The resulting code in the jump slot is:
*
* sethi %hi(. - .PLT0), %g1
* sethi %hh(addr), %g1
* sethi %lm(addr), %g5
* or %g1, %hm(addr), %g1
* sllx %g1, 32, %g1
* or %g1, %g5, %g1
* jmp %g1+%lo(addr)
* nop
*
*/
where[6] = JMP | LOVAL(value, 0);
where[5] = ORG5;
where[4] = SLLX | 32;
where[3] = OR | LOVAL(value, 32);
where[2] = SETHIG5 | HIVAL(value, 10);
where[1] = SETHI | HIVAL(value, 42);
__asm volatile("iflush %0+24" : : "r" (where));
__asm volatile("iflush %0+20" : : "r" (where));
__asm volatile("iflush %0+16" : : "r" (where));
__asm volatile("iflush %0+12" : : "r" (where));
__asm volatile("iflush %0+8" : : "r" (where));
__asm volatile("iflush %0+4" : : "r" (where));
}
if (tp)
*tp = value;
return 0;
}
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