1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright (c) 1995, 2010, Oracle and/or its affiliates. All rights reserved.
24 */
25
26 /*
27 * Copyright 2019 Joyent, Inc.
28 */
29
30 /*
31 * While this is no longer relevant to the kernel, we keep it in its
32 * traditional location to match the other variants, used from the ld
33 * code.
34 */
35
36 #define ELF_TARGET_386
37 #if defined(DO_RELOC_LIBLD)
38 #undef DO_RELOC_LIBLD
39 #define DO_RELOC_LIBLD_X86
40 #endif
41 #include <stdio.h>
42 #include "sgs.h"
43 #include "machdep.h"
44 #include "libld.h"
45 #include "reloc.h"
46 #include "conv.h"
47 #include "msg.h"
48
49 /*
50 * We need to build this code differently when it is used for
51 * cross linking:
52 * - Data alignment requirements can differ from those
53 * of the running system, so we can't access data
54 * in units larger than a byte
55 * - We have to include code to do byte swapping when the
56 * target and linker host use different byte ordering,
57 * but such code is a waste when running natively.
58 */
59 #if !defined(DO_RELOC_LIBLD) || defined(__i386) || defined(__amd64)
60 #define DORELOC_NATIVE
61 #endif
62
63 /*
64 * This table represents the current relocations that do_reloc() is able to
65 * process. The relocations below that are marked SPECIAL are relocations that
66 * take special processing and shouldn't actually ever be passed to do_reloc().
67 */
68 const Rel_entry reloc_table[R_386_NUM] = {
69 /* R_386_NONE */ {0, FLG_RE_NOTREL, 0, 0, 0},
70 /* R_386_32 */ {0, FLG_RE_NOTREL, 4, 0, 0},
71 /* R_386_PC32 */ {0, FLG_RE_PCREL, 4, 0, 0},
72 /* R_386_GOT32 */ {0, FLG_RE_GOTADD, 4, 0, 0},
73 /* R_386_PLT32 */ {0, FLG_RE_PLTREL | FLG_RE_PCREL, 4, 0, 0},
74 /* R_386_COPY */ {0, FLG_RE_NOTREL, 0, 0, 0}, /* SPECIAL */
75 /* R_386_GLOB_DAT */ {0, FLG_RE_NOTREL, 4, 0, 0},
76 /* R_386_JMP_SLOT */ {0, FLG_RE_NOTREL, 4, 0, 0}, /* SPECIAL */
77 /* R_386_RELATIVE */ {0, FLG_RE_NOTREL, 4, 0, 0},
78 /* R_386_GOTOFF */ {0, FLG_RE_GOTREL, 4, 0, 0},
79 /* R_386_GOTPC */ {0, FLG_RE_PCREL | FLG_RE_GOTPC | FLG_RE_LOCLBND, 4,
80 0, 0},
81 /* R_386_32PLT */ {0, FLG_RE_PLTREL, 4, 0, 0},
82 /* R_386_TLS_GD_PLT */ {0, FLG_RE_PLTREL | FLG_RE_PCREL | FLG_RE_TLSGD, 4,
83 0, 0},
84 /* R_386_TLS_LDM_PLT */ {0, FLG_RE_PLTREL | FLG_RE_PCREL | FLG_RE_TLSLD, 4,
85 0, 0},
86 /* R_386_TLS_TPOFF */ {0, FLG_RE_NOTREL, 4, 0, 0},
87 /* R_386_TLS_IE */ {0, FLG_RE_GOTADD | FLG_RE_TLSIE, 4, 0, 0},
88 /* R_386_TLS_GOTIE */ {0, FLG_RE_GOTADD | FLG_RE_TLSIE, 4, 0, 0},
89 /* R_386_TLS_LE */ {0, FLG_RE_TLSLE, 4, 0, 0},
90 /* R_386_TLS_GD */ {0, FLG_RE_GOTADD | FLG_RE_TLSGD, 4, 0, 0},
91 /* R_386_TLS_LDM */ {0, FLG_RE_GOTADD | FLG_RE_TLSLD, 4, 0, 0},
92 /* R_386_16 */ {0, FLG_RE_NOTREL, 2, 0, 0},
93 /* R_386_PC16 */ {0, FLG_RE_PCREL, 2, 0, 0},
94 /* R_386_8 */ {0, FLG_RE_NOTREL, 1, 0, 0},
95 /* R_386_PC8 */ {0, FLG_RE_PCREL, 1, 0, 0},
96 /* R_386_UNKNOWN24 */ {0, FLG_RE_NOTSUP, 0, 0, 0},
97 /* R_386_UNKNOWN25 */ {0, FLG_RE_NOTSUP, 0, 0, 0},
98 /* R_386_UNKNOWN26 */ {0, FLG_RE_NOTSUP, 0, 0, 0},
99 /* R_386_UNKNOWN27 */ {0, FLG_RE_NOTSUP, 0, 0, 0},
100 /* R_386_UNKNOWN28 */ {0, FLG_RE_NOTSUP, 0, 0, 0},
101 /* R_386_UNKNOWN29 */ {0, FLG_RE_NOTSUP, 0, 0, 0},
102 /* R_386_UNKNOWN30 */ {0, FLG_RE_NOTSUP, 0, 0, 0},
103 /* R_386_UNKNOWN31 */ {0, FLG_RE_NOTSUP, 0, 0, 0},
104 /* R_386_TLS_LDO_32 */ {0, FLG_RE_TLSLD, 4, 0, 0},
105 /* R_386_UNKNOWN33 */ {0, FLG_RE_NOTSUP, 0, 0, 0},
106 /* R_386_UNKNOWN34 */ {0, FLG_RE_NOTSUP, 0, 0, 0},
107 /* R_386_TLS_DTPMOD32 */ {0, FLG_RE_NOTREL, 4, 0, 0},
108 /* R_386_TLS_DTPOFF32 */ {0, FLG_RE_NOTREL, 4, 0, 0},
109 /* R_386_UNKONWN37 */ {0, FLG_RE_NOTSUP, 0, 0, 0},
110 /* R_386_SIZE32 */ {0, FLG_RE_SIZE | FLG_RE_VERIFY, 4, 0, 0}
111 };
112
113 /*
114 * Write a single relocated value to its reference location.
115 * We assume we wish to add the relocation amount, value, to the
116 * value of the address already present at the offset.
117 *
118 * NAME VALUE FIELD CALCULATION
119 *
120 * R_386_NONE 0 none none
121 * R_386_32 1 word32 S + A
122 * R_386_PC32 2 word32 S + A - P
123 * R_386_GOT32 3 word32 G + A - P
124 * R_386_PLT32 4 word32 L + A - P
125 * R_386_COPY 5 none none
126 * R_386_GLOB_DAT 6 word32 S
127 * R_386_JMP_SLOT 7 word32 S
128 * R_386_RELATIVE 8 word32 B + A
129 * R_386_GOTOFF 9 word32 S + A - GOT
130 * R_386_GOTPC 10 word32 GOT + A - P
131 * R_386_32PLT 11 word32 L + A
132 * R_386_TLS_GD_PLT 12 word32 @tlsgdplt
133 * R_386_TLS_LDM_PLT 13 word32 @tlsldmplt
134 * R_386_TLS_TPOFF 14 word32 @ntpoff(S)
135 * R_386_TLS_IE 15 word32 @indntpoff(S)
136 * R_386_TLS_GD 18 word32 @tlsgd(S)
137 * R_386_TLS_LDM 19 word32 @tlsldm(S)
138 * R_386_16 20 word16 S + A
139 * R_386_PC16 21 word16 S + A - P
140 * R_386_8 22 word8 S + A
141 * R_386_PC8 23 word8 S + A - P
142 * R_386_TLS_LDO_32 32 word32 @dtpoff(S)
143 * R_386_TLS_DTPMOD32 35 word32 @dtpmod(S)
144 * R_386_TLS_DTPOFF32 36 word32 @dtpoff(S)
145 * R_386_SIZE32 38 word32 Z + A
146 *
147 * Relocations 0-10 are from Figure 4-4: Relocation Types from the
148 * intel ABI. Relocation 11 (R_386_32PLT) is from the C++ intel abi
149 * and is in the process of being registered with intel ABI (1/13/94).
150 *
151 * Relocations R_386_TLS_* are added to support Thread-Local storage
152 * as recorded in PSARC/2001/509
153 *
154 * Relocation calculations:
155 *
156 * CALCULATION uses the following notation:
157 * A the addend used
158 * B the base address of the shared object in memory
159 * G the offset into the global offset table
160 * GOT the address of teh global offset table
161 * L the procedure linkage entry
162 * P the place of the storage unit being relocated
163 * S the value of the symbol
164 * Z the size of the symbol whose index resides in the relocation
165 * entry
166 *
167 * @dtlndx(x): Allocate two contiguous entries in the GOT table to hold
168 * a Tls_index structure (for passing to __tls_get_addr()). The
169 * instructions referencing this entry will be bound to the first
170 * of the two GOT entries.
171 *
172 * @tmndx(x): Allocate two contiguous entries in the GOT table to hold
173 * a Tls_index structure (for passing to __tls_get_addr()). The
174 * ti_offset field of the Tls_index will be set to 0 (zero) and the
175 * ti_module will be filled in at run-time. The call to
176 * __tls_get_addr() will return the starting offset of the dynamic
177 * TLS block.
178 *
179 * @dtpoff(x): calculate the tlsoffset relative to the TLS block.
180 *
181 * @tpoff(x): calculate the tlsoffset relative to the TLS block.
182 *
183 * @dtpmod(x): calculate the module id of the object containing symbol x.
184 *
185 * The calculations in the CALCULATION column are assumed to have
186 * been performed before calling this function except for the addition of
187 * the addresses in the instructions.
188 */
189 #if defined(DO_RELOC_LIBLD)
190 /*ARGSUSED5*/
191 int
192 do_reloc_ld(Rel_desc *rdesc, uchar_t *off, Xword *value,
193 rel_desc_sname_func_t rel_desc_sname_func,
194 const char *file, int bswap, void *lml)
195 #else
196 int
197 do_reloc_rtld(uchar_t rtype, uchar_t *off, Xword *value, const char *sym,
198 const char *file, void *lml)
199 #endif
200 {
201 #ifdef DO_RELOC_LIBLD
202 #define sym (* rel_desc_sname_func)(rdesc)
203 uchar_t rtype = rdesc->rel_rtype;
204 #endif
205 const Rel_entry *rep;
206
207 rep = &reloc_table[rtype];
208
209 switch (rep->re_fsize) {
210 case 1:
211 /* LINTED */
212 *((uchar_t *)off) += (uchar_t)(*value);
213 break;
214
215 case 2:
216 #if defined(DORELOC_NATIVE)
217 /* LINTED */
218 *((Half *)off) += (Half)(*value);
219 #else
220 {
221 Half v;
222 uchar_t *v_bytes = (uchar_t *)&v;
223
224 if (bswap) {
225 UL_ASSIGN_BSWAP_HALF(v_bytes, off);
226 v += *value;
227 UL_ASSIGN_BSWAP_HALF(off, v_bytes);
228 } else {
229 UL_ASSIGN_HALF(v_bytes, off);
230 v += *value;
231 UL_ASSIGN_HALF(off, v_bytes);
232 }
233 }
234 #endif
235 break;
236
237 case 4:
238 #if defined(DORELOC_NATIVE)
239 /* LINTED */
240 *((Xword *)off) += *value;
241 #else
242 {
243 Word v;
244 uchar_t *v_bytes = (uchar_t *)&v;
245
246 if (bswap) {
247 UL_ASSIGN_BSWAP_WORD(v_bytes, off);
248 v += *value;
249 UL_ASSIGN_BSWAP_WORD(off, v_bytes);
250 } else {
251 UL_ASSIGN_WORD(v_bytes, off);
252 v += *value;
253 UL_ASSIGN_WORD(off, v_bytes);
254 }
255 }
256 #endif
257 break;
258 default:
259 /*
260 * To keep chkmsg() happy: MSG_INTL(MSG_REL_UNSUPSZ)
261 */
262 REL_ERR_UNSUPSZ(lml, file, sym, rtype, rep->re_fsize);
263 return (0);
264 }
265 return (1);
266
267 #ifdef DO_RELOC_LIBLD
268 #undef sym
269 #endif
270 }