1 /* $NetBSD: kobj_machdep.c,v 1.6 2023/04/28 07:33:56 skrll Exp $ */
2
3 /*-
4 * Copyright (c) 1999, 2002, 2008 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Paul Kranenburg and by Charles M. Hannum.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32 #define ELFSIZE ARCH_ELFSIZE
33
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/kobj.h>
37 #include <sys/exec.h>
38 #include <sys/exec_elf.h>
39
40 /*
41 * The following table holds for each relocation type:
42 * - the width in bits of the memory location the relocation
43 * applies to (not currently used)
44 * - the number of bits the relocation value must be shifted to the
45 * right (i.e. discard least significant bits) to fit into
46 * the appropriate field in the instruction word.
47 * - flags indicating whether
48 * * the relocation involves a symbol
49 * * the relocation is relative to the current position
50 * * the relocation is for a GOT entry
51 * * the relocation is relative to the load address
52 *
53 */
54 #define _RF_S 0x80000000 /* Resolve symbol */
55 #define _RF_A 0x40000000 /* Use addend */
56 #define _RF_P 0x20000000 /* Location relative */
57 #define _RF_G 0x10000000 /* GOT offset */
58 #define _RF_B 0x08000000 /* Load address relative */
59 #define _RF_U 0x04000000 /* Unaligned */
60 #define _RF_SZ(s) (((s) & 0xff) << 8) /* memory target size */
61 #define _RF_RS(s) ( (s) & 0xff) /* right shift */
62 static const int reloc_target_flags[] = {
63 0, /* NONE */
64 _RF_S|_RF_A| _RF_SZ(8) | _RF_RS(0), /* RELOC_8 */
65 _RF_S|_RF_A| _RF_SZ(16) | _RF_RS(0), /* RELOC_16 */
66 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* RELOC_32 */
67 _RF_S|_RF_A|_RF_P| _RF_SZ(8) | _RF_RS(0), /* DISP_8 */
68 _RF_S|_RF_A|_RF_P| _RF_SZ(16) | _RF_RS(0), /* DISP_16 */
69 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* DISP_32 */
70 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_30 */
71 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WDISP_22 */
72 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(10), /* HI22 */
73 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 22 */
74 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* 13 */
75 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* LO10 */
76 _RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT10 */
77 _RF_G| _RF_SZ(32) | _RF_RS(0), /* GOT13 */
78 _RF_G| _RF_SZ(32) | _RF_RS(10), /* GOT22 */
79 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(0), /* PC10 */
80 _RF_S|_RF_A|_RF_P| _RF_SZ(32) | _RF_RS(10), /* PC22 */
81 _RF_A|_RF_P| _RF_SZ(32) | _RF_RS(2), /* WPLT30 */
82 _RF_SZ(32) | _RF_RS(0), /* COPY */
83 _RF_S|_RF_A| _RF_SZ(32) | _RF_RS(0), /* GLOB_DAT */
84 _RF_SZ(32) | _RF_RS(0), /* JMP_SLOT */
85 _RF_A| _RF_B| _RF_SZ(32) | _RF_RS(0), /* RELATIVE */
86 _RF_S|_RF_A| _RF_U| _RF_SZ(32) | _RF_RS(0), /* UA_32 */
87 };
88
89 #ifdef RTLD_DEBUG_RELOC
90 static const char *reloc_names[] = {
91 "NONE", "RELOC_8", "RELOC_16", "RELOC_32", "DISP_8",
92 "DISP_16", "DISP_32", "WDISP_30", "WDISP_22", "HI22",
93 "22", "13", "LO10", "GOT10", "GOT13",
94 "GOT22", "PC10", "PC22", "WPLT30", "COPY",
95 "GLOB_DAT", "JMP_SLOT", "RELATIVE", "UA_32"
96 };
97 #endif
98
99 #define RELOC_RESOLVE_SYMBOL(t) ((reloc_target_flags[t] & _RF_S) != 0)
100 #define RELOC_PC_RELATIVE(t) ((reloc_target_flags[t] & _RF_P) != 0)
101 #define RELOC_BASE_RELATIVE(t) ((reloc_target_flags[t] & _RF_B) != 0)
102 #define RELOC_UNALIGNED(t) ((reloc_target_flags[t] & _RF_U) != 0)
103 #define RELOC_USE_ADDEND(t) ((reloc_target_flags[t] & _RF_A) != 0)
104 #define RELOC_TARGET_SIZE(t) ((reloc_target_flags[t] >> 8) & 0xff)
105 #define RELOC_VALUE_RIGHTSHIFT(t) (reloc_target_flags[t] & 0xff)
106
107 static const int reloc_target_bitmask[] = {
108 #define _BM(x) (~(-(1ULL << (x))))
109 0, /* NONE */
110 _BM(8), _BM(16), _BM(32), /* RELOC_8, _16, _32 */
111 _BM(8), _BM(16), _BM(32), /* DISP8, DISP16, DISP32 */
112 _BM(30), _BM(22), /* WDISP30, WDISP22 */
113 _BM(22), _BM(22), /* HI22, _22 */
114 _BM(13), _BM(10), /* RELOC_13, _LO10 */
115 _BM(10), _BM(13), _BM(22), /* GOT10, GOT13, GOT22 */
116 _BM(10), _BM(22), /* _PC10, _PC22 */
117 _BM(30), 0, /* _WPLT30, _COPY */
118 -1, -1, -1, /* _GLOB_DAT, JMP_SLOT, _RELATIVE */
119 _BM(32) /* _UA32 */
120 #undef _BM
121 };
122 #define RELOC_VALUE_BITMASK(t) (reloc_target_bitmask[t])
123
124 int
kobj_reloc(kobj_t ko,uintptr_t relocbase,const void * data,bool isrela,bool local)125 kobj_reloc(kobj_t ko, uintptr_t relocbase, const void *data,
126 bool isrela, bool local)
127 {
128 const Elf_Rela *rela;
129 Elf_Addr *where, addr;
130 Elf_Word value, mask;
131 uintptr_t tmp;
132 u_int symidx, type;
133 int error;
134
135 rela = data;
136 where = (Elf_Addr *) (relocbase + rela->r_offset);
137 symidx = ELF_R_SYM(rela->r_info);
138 type = ELF_R_TYPE(rela->r_info);
139 value = rela->r_addend;
140
141 const Elf_Sym *sym = kobj_symbol(ko, symidx);
142
143 if (!local && ELF_ST_BIND(sym->st_info) == STB_LOCAL) {
144 return 0;
145 }
146
147 if (type == R_TYPE(NONE))
148 return 0;
149
150 if (!isrela) {
151 printf("kobj_reloc: only support RELA relocations\n");
152 return -1;
153 }
154
155 if (type == R_TYPE(JMP_SLOT) || type == R_TYPE(COPY) ||
156 type > R_TYPE(6)) {
157 printf("kobj_reloc: unexpected reloc type %d\n", type);
158 return -1;
159 }
160
161 if (type == R_TYPE(RELATIVE)) {
162 *where += (Elf_Addr)(relocbase + value);
163 return 0;
164 }
165
166 if (RELOC_RESOLVE_SYMBOL(type)) {
167 error = kobj_sym_lookup(ko, symidx, &addr);
168 if (error)
169 return -1;
170 value += addr;
171 }
172
173 if (RELOC_PC_RELATIVE(type)) {
174 value -= (Elf_Word)where;
175 }
176
177 if (RELOC_BASE_RELATIVE(type)) {
178 value += (Elf_Word)(relocbase + *where);
179 }
180
181 mask = RELOC_VALUE_BITMASK(type);
182 value >>= RELOC_VALUE_RIGHTSHIFT(type);
183 value &= mask;
184
185 if (RELOC_UNALIGNED(type)) {
186 /* Handle unaligned relocations. */
187 char *ptr = (char *)where;
188 int i, size = RELOC_TARGET_SIZE(type)/8;
189
190 /* Read it in one byte at a time. */
191 for (i = 0, tmp = 0; i < size; i++)
192 tmp = (tmp << 8) | ptr[i];
193
194 tmp &= ~mask;
195 tmp |= value;
196
197 /* Write it back out. */
198 for (i=0; i<size; i++)
199 ptr[i] = ((tmp >> (8*i)) & 0xff);
200
201 } else {
202 *where &= ~mask;
203 *where |= value;
204 }
205
206 return 0;
207 }
208
209 int
kobj_machdep(kobj_t ko,void * base,size_t size,bool load)210 kobj_machdep(kobj_t ko, void *base, size_t size, bool load)
211 {
212
213 return 0;
214 }
215