323 lines
11 KiB
C
323 lines
11 KiB
C
/* $NetBSD: mdreloc.c,v 1.10 2001/04/25 12:24:51 kleink Exp $ */
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/*-
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* Copyright (c) 1999 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Paul Kranenburg.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/stat.h>
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#include "rtldenv.h"
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#include "debug.h"
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#include "rtld.h"
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/*
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* The following table holds for each relocation type:
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* - the width in bits of the memory location the relocation
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* applies to (not currently used)
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* - the number of bits the relocation value must be shifted to the
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* right (i.e. discard least significant bits) to fit into
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* the appropriate field in the instruction word.
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* - flags indicating whether
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* * the relocation involves a symbol
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* * the relocation is relative to the current position
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* * the relocation is for a GOT entry
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* * the relocation is relative to the load address
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*
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*/
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#define _RF_S 0x80000000 /* Resolve symbol */
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#define _RF_A 0x40000000 /* Use addend */
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#define _RF_P 0x20000000 /* Location relative */
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#define _RF_G 0x10000000 /* GOT offset */
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#define _RF_B 0x08000000 /* Load address relative */
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#define _RF_SZ(s) (((s) & 0xff) << 8) /* memory target size */
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#define _RF_RS(s) ( (s) & 0xff) /* right shift */
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static int reloc_target_flags[] = {
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0, /* NONE */
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_RF_S|_RF_A| _RF_SZ(8) | _RF_RS(0), /* RELOC_8 */
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_RF_S|_RF_A| _RF_SZ(16) | _RF_RS(0), /* RELOC_16 */
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_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* RELOC_32 */
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_RF_S|_RF_A|_RF_P| _RF_SZ(8) | _RF_RS(0), /* DISP_8 */
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_RF_S|_RF_A|_RF_P| _RF_SZ(16) | _RF_RS(0), /* DISP_16 */
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_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* DISP_32 */
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_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_30 */
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_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_22 */
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_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HI22 */
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_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 22 */
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_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 13 */
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_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LO10 */
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_RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT10 */
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_RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT13 */
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_RF_G| _RF_SZ(32) | _RF_RS(10), /* GOT22 */
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_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PC10 */
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_RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC22 */
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_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WPLT30 */
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_RF_SZ(32) | _RF_RS(0), /* COPY */
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_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* GLOB_DAT */
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_RF_SZ(32) | _RF_RS(0), /* JMP_SLOT */
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_RF_A| _RF_B| _RF_SZ(32) | _RF_RS(0), /* RELATIVE */
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_RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* UA_32 */
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/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* PLT32 */
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/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* HIPLT22 */
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/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* LOPLT10 */
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/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* LOPLT10 */
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/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* PCPLT22 */
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/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* PCPLT32 */
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_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 10 */
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_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 11 */
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_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 64 */
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_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* OLO10 */
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_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* HH22 */
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_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* HM10 */
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_RF_S|_RF_A|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* LM22 */
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_RF_S|_RF_A|_RF_P|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* WDISP16 */
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_RF_S|_RF_A|_RF_P|/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* WDISP19 */
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/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* GLOB_JMP */
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/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 7 */
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/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 5 */
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/*unknown*/ _RF_SZ(32) | _RF_RS(0), /* 6 */
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};
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#ifdef RTLD_DEBUG_RELOC
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static const char *reloc_names[] = {
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"NONE", "RELOC_8", "RELOC_16", "RELOC_32", "DISP_8",
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"DISP_16", "DISP_32", "WDISP_30", "WDISP_22", "HI22",
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"22", "13", "LO10", "GOT10", "GOT13",
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"GOT22", "PC10", "PC22", "WPLT30", "COPY",
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"GLOB_DAT", "JMP_SLOT", "RELATIVE", "UA_32", "PLT32",
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"HIPLT22", "LOPLT10", "LOPLT10", "PCPLT22", "PCPLT32",
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"10", "11", "64", "OLO10", "HH22",
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"HM10", "LM22", "WDISP16", "WDISP19", "GLOB_JMP",
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"7", "5", "6"
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};
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#endif
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#define RELOC_RESOLVE_SYMBOL(t) ((reloc_target_flags[t] & _RF_S) != 0)
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#define RELOC_PC_RELATIVE(t) ((reloc_target_flags[t] & _RF_P) != 0)
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#define RELOC_BASE_RELATIVE(t) ((reloc_target_flags[t] & _RF_B) != 0)
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#define RELOC_TARGET_SIZE(t) ((reloc_target_flags[t] >> 8) & 0xff)
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#define RELOC_VALUE_RIGHTSHIFT(t) (reloc_target_flags[t] & 0xff)
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static int reloc_target_bitmask[] = {
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#define _BM(x) (~(-(1ULL << (x))))
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0, /* NONE */
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_BM(8), _BM(16), _BM(32), /* RELOC_8, _16, _32 */
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_BM(8), _BM(16), _BM(32), /* DISP8, DISP16, DISP32 */
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_BM(30), _BM(22), /* WDISP30, WDISP22 */
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_BM(22), _BM(22), /* HI22, _22 */
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_BM(13), _BM(10), /* RELOC_13, _LO10 */
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_BM(10), _BM(13), _BM(22), /* GOT10, GOT13, GOT22 */
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_BM(10), _BM(22), /* _PC10, _PC22 */
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_BM(30), 0, /* _WPLT30, _COPY */
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-1, -1, -1, /* _GLOB_DAT, JMP_SLOT, _RELATIVE */
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_BM(32), _BM(32), /* _UA32, PLT32 */
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_BM(22), _BM(10), /* _HIPLT22, LOPLT10 */
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_BM(32), _BM(22), _BM(10), /* _PCPLT32, _PCPLT22, _PCPLT10 */
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_BM(10), _BM(11), -1, /* _10, _11, _64 */
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_BM(10), _BM(22), /* _OLO10, _HH22 */
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_BM(10), _BM(22), /* _HM10, _LM22 */
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_BM(16), _BM(19), /* _WDISP16, _WDISP19 */
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-1, /* GLOB_JMP */
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_BM(7), _BM(5), _BM(6) /* _7, _5, _6 */
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#undef _BM
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};
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#define RELOC_VALUE_BITMASK(t) (reloc_target_bitmask[t])
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int
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_rtld_relocate_nonplt_object(obj, rela, dodebug)
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Obj_Entry *obj;
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const Elf_Rela *rela;
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bool dodebug;
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{
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Elf_Addr *where = (Elf_Addr *) (obj->relocbase + rela->r_offset);
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Elf_Word type, value, mask;
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const Elf_Sym *def = NULL;
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const Obj_Entry *defobj = NULL;
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type = ELF_R_TYPE(rela->r_info);
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if (type == R_TYPE(NONE))
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return (0);
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/* We do JMP_SLOTs in relocate_plt_object() below */
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if (type == R_TYPE(JMP_SLOT))
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return (0);
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/* COPY relocs are also handled elsewhere */
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if (type == R_TYPE(COPY))
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return (0);
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/*
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* We use the fact that relocation types are an `enum'
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* Note: R_SPARC_6 is currently numerically largest.
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*/
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if (type > R_TYPE(6))
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return (-1);
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value = rela->r_addend;
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/*
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* Handle relative relocs here, because we might not
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* be able to access globals yet.
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*/
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if (!dodebug && type == R_TYPE(RELATIVE)) {
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*where += (Elf_Addr)(obj->relocbase + value);
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return (0);
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}
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if (RELOC_RESOLVE_SYMBOL(type)) {
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/* Find the symbol */
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def = _rtld_find_symdef(_rtld_objlist, rela->r_info,
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NULL, obj, &defobj, false);
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if (def == NULL)
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return (-1);
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/* Add in the symbol's absolute address */
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value += (Elf_Word)(defobj->relocbase + def->st_value);
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}
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if (RELOC_PC_RELATIVE(type)) {
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value -= (Elf_Word)where;
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}
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if (RELOC_BASE_RELATIVE(type)) {
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/*
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* Note that even though sparcs use `Elf_rela' exclusively
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* we still need the implicit memory addend in relocations
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* referring to GOT entries. Undoubtedly, someone f*cked
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* this up in the distant past, and now we're stuck with
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* it in the name of compatibility for all eternity..
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*
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* In any case, the implicit and explicit should be mutually
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* exclusive. We provide a check for that here.
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*/
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#define DIAGNOSTIC
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#ifdef DIAGNOSTIC
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if (value != 0 && *where != 0) {
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xprintf("BASE_REL(%s): where=%p, *where 0x%x, "
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"addend=0x%x, base %p\n",
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obj->path, where, *where,
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rela->r_addend, obj->relocbase);
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}
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#endif
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value += (Elf_Word)(obj->relocbase + *where);
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}
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mask = RELOC_VALUE_BITMASK(type);
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value >>= RELOC_VALUE_RIGHTSHIFT(type);
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value &= mask;
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/* We ignore alignment restrictions here */
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*where &= ~mask;
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*where |= value;
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#ifdef RTLD_DEBUG_RELOC
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if (RELOC_RESOLVE_SYMBOL(type)) {
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rdbg(dodebug, ("%s %s in %s --> %p %s",
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reloc_names[type],
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defobj->strtab + def->st_name, obj->path,
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(void *)*where, defobj->path));
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}
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else {
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rdbg(dodebug, ("%s --> %p", reloc_names[type],
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(void *)*where));
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}
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#endif
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return (0);
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}
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int
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_rtld_relocate_plt_object(obj, rela, addrp, bind_now, dodebug)
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Obj_Entry *obj;
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const Elf_Rela *rela;
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caddr_t *addrp;
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bool bind_now;
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bool dodebug;
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{
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const Elf_Sym *def;
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const Obj_Entry *defobj;
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Elf_Addr *where = (Elf_Addr *) (obj->relocbase + rela->r_offset);
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Elf_Addr value;
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if (bind_now == 0 && obj->pltgot != NULL)
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return (0);
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/* Fully resolve procedure addresses now */
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assert(ELF_R_TYPE(rela->r_info) == R_TYPE(JMP_SLOT));
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def = _rtld_find_symdef(_rtld_objlist, rela->r_info,
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NULL, obj, &defobj, true);
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if (def == NULL)
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return (-1);
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value = (Elf_Addr) (defobj->relocbase + def->st_value);
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rdbg(dodebug, ("bind now %d/fixup in %s --> old=%p new=%p",
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(int)bind_now, defobj->strtab + def->st_name,
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(void *)*where, (void *)value));
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/*
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* At the PLT entry pointed at by `where', we now construct
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* a direct transfer to the now fully resolved function
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* address. The resulting code in the jump slot is:
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*
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* sethi %hi(roffset), %g1
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* sethi %hi(addr), %g1
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* jmp %g1+%lo(addr)
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*
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* We write the third instruction first, since that leaves the
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* previous `b,a' at the second word in place. Hence the whole
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* PLT slot can be atomically change to the new sequence by
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* writing the `sethi' instruction at word 2.
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*/
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#define SETHI 0x03000000
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#define JMP 0x81c06000
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#define NOP 0x01000000
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where[2] = JMP | (value & 0x000003ff);
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where[1] = SETHI | ((value >> 10) & 0x003fffff);
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__asm __volatile("iflush %0+8" : : "r" (where));
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__asm __volatile("iflush %0+4" : : "r" (where));
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if (addrp != NULL)
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*addrp = (caddr_t)value;
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return (0);
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}
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