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7389debf ILT |
1 | /* Support for 32-bit i386 NLM (NetWare Loadable Module) |
2 | Copyright (C) 1993 Free Software Foundation, Inc. | |
3 | ||
4 | This file is part of BFD, the Binary File Descriptor library. | |
5 | ||
6 | This program is free software; you can redistribute it and/or modify | |
7 | it under the terms of the GNU General Public License as published by | |
8 | the Free Software Foundation; either version 2 of the License, or | |
9 | (at your option) any later version. | |
10 | ||
11 | This program is distributed in the hope that it will be useful, | |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | GNU General Public License for more details. | |
15 | ||
16 | You should have received a copy of the GNU General Public License | |
17 | along with this program; if not, write to the Free Software | |
18 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
19 | ||
20 | #include "bfd.h" | |
21 | #include "sysdep.h" | |
22 | #include "libbfd.h" | |
23 | ||
24 | #define ARCH_SIZE 32 | |
25 | #include "libnlm.h" | |
26 | ||
27 | static boolean nlm_i386_read_reloc | |
28 | PARAMS ((bfd *, nlmNAME(symbol_type) *, asection **, arelent *)); | |
29 | static boolean nlm_i386_write_reloc | |
30 | PARAMS ((bfd *, asection *, arelent *)); | |
31 | static boolean nlm_i386_mangle_relocs | |
32 | PARAMS ((bfd *, asection *, PTR, bfd_vma, bfd_size_type)); | |
33 | ||
34 | /* Adjust the reloc location by an absolute value. */ | |
35 | ||
36 | static reloc_howto_type nlm_i386_abs_howto = | |
37 | HOWTO (0, /* type */ | |
38 | 0, /* rightshift */ | |
39 | 2, /* size (0 = byte, 1 = short, 2 = long) */ | |
40 | 32, /* bitsize */ | |
41 | false, /* pc_relative */ | |
42 | 0, /* bitpos */ | |
43 | complain_overflow_bitfield, /* complain_on_overflow */ | |
44 | 0, /* special_function */ | |
45 | "32", /* name */ | |
46 | true, /* partial_inplace */ | |
47 | 0xffffffff, /* src_mask */ | |
48 | 0xffffffff, /* dst_mask */ | |
49 | false); /* pcrel_offset */ | |
50 | ||
51 | /* Adjust the reloc location by a PC relative displacement. */ | |
52 | ||
53 | static reloc_howto_type nlm_i386_pcrel_howto = | |
54 | HOWTO (1, /* type */ | |
55 | 0, /* rightshift */ | |
56 | 2, /* size (0 = byte, 1 = short, 2 = long) */ | |
57 | 32, /* bitsize */ | |
58 | true, /* pc_relative */ | |
59 | 0, /* bitpos */ | |
60 | complain_overflow_signed, /* complain_on_overflow */ | |
61 | 0, /* special_function */ | |
62 | "DISP32", /* name */ | |
63 | true, /* partial_inplace */ | |
64 | 0xffffffff, /* src_mask */ | |
65 | 0xffffffff, /* dst_mask */ | |
66 | true); /* pcrel_offset */ | |
67 | ||
68 | /* Read a NetWare i386 reloc. */ | |
69 | ||
70 | static boolean | |
71 | nlm_i386_read_reloc (abfd, sym, secp, rel) | |
72 | bfd *abfd; | |
73 | nlmNAME(symbol_type) *sym; | |
74 | asection **secp; | |
75 | arelent *rel; | |
76 | { | |
77 | bfd_byte temp[4]; | |
78 | bfd_vma val; | |
79 | const char *name; | |
80 | ||
81 | if (bfd_read (temp, sizeof (temp), 1, abfd) != sizeof (temp)) | |
82 | { | |
83 | bfd_error = system_call_error; | |
84 | return false; | |
85 | } | |
86 | ||
87 | val = bfd_get_32 (abfd, temp); | |
88 | ||
89 | /* The value is an offset into either the code or data segment. | |
90 | This is the location which needs to be adjusted. | |
91 | ||
92 | If this is a relocation fixup rather than an imported symbol (the | |
93 | sym argument is NULL) then the high bit is 0 if the location | |
94 | needs to be adjusted by the address of the data segment, or 1 if | |
95 | the location needs to be adjusted by the address of the code | |
96 | segment. If this is an imported symbol, then the high bit is 0 | |
97 | if the location is 0 if the location should be adjusted by the | |
98 | offset to the symbol, or 1 if the location should adjusted by the | |
99 | absolute value of the symbol. | |
100 | ||
101 | The second most significant bit is 0 if the value is an offset | |
102 | into the data segment, or 1 if the value is an offset into the | |
103 | code segment. | |
104 | ||
105 | All this translates fairly easily into a BFD reloc. */ | |
106 | ||
107 | if (sym == NULL) | |
108 | { | |
109 | if ((val & NLM_HIBIT) == 0) | |
110 | name = NLM_INITIALIZED_DATA_NAME; | |
111 | else | |
112 | { | |
113 | name = NLM_CODE_NAME; | |
114 | val &=~ NLM_HIBIT; | |
115 | } | |
116 | rel->sym_ptr_ptr = bfd_get_section_by_name (abfd, name)->symbol_ptr_ptr; | |
117 | rel->howto = &nlm_i386_abs_howto; | |
118 | } | |
119 | else | |
120 | { | |
121 | /* In this case we do not need to set the sym_ptr_ptr field. */ | |
122 | rel->sym_ptr_ptr = NULL; | |
123 | if ((val & NLM_HIBIT) == 0) | |
124 | rel->howto = &nlm_i386_pcrel_howto; | |
125 | else | |
126 | { | |
127 | rel->howto = &nlm_i386_abs_howto; | |
128 | val &=~ NLM_HIBIT; | |
129 | } | |
130 | } | |
131 | ||
132 | if ((val & (NLM_HIBIT >> 1)) == 0) | |
133 | *secp = bfd_get_section_by_name (abfd, NLM_INITIALIZED_DATA_NAME); | |
134 | else | |
135 | { | |
136 | *secp = bfd_get_section_by_name (abfd, NLM_CODE_NAME); | |
137 | val &=~ (NLM_HIBIT >> 1); | |
138 | } | |
139 | ||
140 | rel->address = val; | |
141 | rel->addend = 0; | |
142 | ||
143 | return true; | |
144 | } | |
145 | ||
146 | /* Write a NetWare i386 reloc. */ | |
147 | ||
148 | static boolean | |
149 | nlm_i386_write_reloc (abfd, sec, rel) | |
150 | bfd *abfd; | |
151 | asection *sec; | |
152 | arelent *rel; | |
153 | { | |
154 | asymbol *sym; | |
155 | bfd_vma val; | |
156 | bfd_byte temp[4]; | |
157 | ||
158 | /* NetWare only supports two kinds of relocs. We should check | |
159 | special_function here, as well, but at the moment coff-i386 | |
160 | relocs uses a special_function which does not affect what we do | |
161 | here. */ | |
162 | if (rel->addend != 0 | |
163 | || rel->howto == NULL | |
164 | || rel->howto->rightshift != 0 | |
165 | || rel->howto->size != 2 | |
166 | || rel->howto->bitsize != 32 | |
167 | || rel->howto->bitpos != 0 | |
168 | || ! rel->howto->partial_inplace | |
169 | || rel->howto->src_mask != 0xffffffff | |
170 | || rel->howto->dst_mask != 0xffffffff) | |
171 | { | |
172 | bfd_error = invalid_operation; | |
173 | return false; | |
174 | } | |
175 | ||
176 | sym = *rel->sym_ptr_ptr; | |
177 | ||
178 | /* The value we write out is the offset into the appropriate | |
179 | segment. This offset is the section vma, adjusted by the vma of | |
180 | the lowest section in that segment, plus the address of the | |
181 | relocation. */ | |
182 | val = bfd_get_section_vma (abfd, sec) + rel->address; | |
183 | ||
184 | /* The second most significant bit is 0 if the value is an offset | |
185 | into the data segment, or 1 if the value is an offset into the | |
186 | code segment. */ | |
187 | if (bfd_get_section_flags (abfd, sec) & SEC_CODE) | |
188 | { | |
189 | val -= nlm_get_text_low (abfd); | |
190 | val |= NLM_HIBIT >> 1; | |
191 | } | |
192 | else | |
193 | val -= nlm_get_data_low (abfd); | |
194 | ||
195 | if (bfd_get_section (sym) != &bfd_und_section) | |
196 | { | |
197 | /* NetWare only supports absolute internal relocs. */ | |
198 | if (rel->howto->pc_relative) | |
199 | { | |
200 | bfd_error = invalid_operation; | |
201 | return false; | |
202 | } | |
203 | ||
204 | /* The high bit is 1 if the reloc is against the code section, 0 | |
205 | if against the data section. */ | |
206 | if (bfd_get_section_flags (abfd, bfd_get_section (sym)) & SEC_CODE) | |
207 | val |= NLM_HIBIT; | |
208 | } | |
209 | else | |
210 | { | |
211 | /* The high bit is 1 if this is an absolute reloc, 0 if it is PC | |
212 | relative. */ | |
213 | if (! rel->howto->pc_relative) | |
214 | val |= NLM_HIBIT; | |
215 | else | |
216 | { | |
217 | /* PC relative relocs on NetWare must be pcrel_offset. */ | |
218 | if (! rel->howto->pcrel_offset) | |
219 | { | |
220 | bfd_error = invalid_operation; | |
221 | return false; | |
222 | } | |
223 | } | |
224 | } | |
225 | ||
226 | bfd_put_32 (abfd, val, temp); | |
227 | if (bfd_write (temp, sizeof (temp), 1, abfd) != sizeof (temp)) | |
228 | { | |
229 | bfd_error = system_call_error; | |
230 | return false; | |
231 | } | |
232 | ||
233 | return true; | |
234 | } | |
235 | ||
236 | /* I want to be able to use objcopy to turn a i386 a.out or COFF file | |
237 | into a NetWare i386 module. That means that the relocs from the | |
238 | source file have to be mapped into relocs that apply to the target | |
239 | file. This function is called by nlm_set_section_contents to give | |
240 | it a chance to rework the relocs. | |
241 | ||
242 | This is actually a fairly general concept. However, this is not a | |
243 | general implementation. */ | |
244 | ||
245 | static boolean | |
246 | nlm_i386_mangle_relocs (abfd, sec, data, offset, count) | |
247 | bfd *abfd; | |
248 | asection *sec; | |
249 | PTR data; | |
250 | bfd_vma offset; | |
251 | bfd_size_type count; | |
252 | { | |
253 | arelent **rel_ptr_ptr, **rel_end; | |
254 | ||
255 | rel_ptr_ptr = sec->orelocation; | |
256 | rel_end = rel_ptr_ptr + sec->reloc_count; | |
257 | for (; rel_ptr_ptr < rel_end; rel_ptr_ptr++) | |
258 | { | |
259 | arelent *rel; | |
260 | asymbol *sym; | |
261 | bfd_vma addend; | |
262 | ||
263 | rel = *rel_ptr_ptr; | |
264 | sym = *rel->sym_ptr_ptr; | |
265 | ||
266 | /* Note that no serious harm will ensue if we fail to change a | |
267 | reloc. We will wind up failing in nlm_i386_write_reloc. */ | |
268 | ||
269 | /* Make sure this reloc is within the data we have. We only 4 | |
270 | byte relocs here, so we insist on having 4 bytes. */ | |
271 | if (rel->address < offset | |
272 | || rel->address + 4 > offset + count) | |
273 | continue; | |
274 | ||
275 | /* NetWare doesn't support reloc addends, so we get rid of them | |
276 | here by simply adding them into the object data. We handle | |
277 | the symbol value, if any, the same way. */ | |
278 | addend = rel->addend + sym->value; | |
279 | ||
280 | /* The value of a symbol is the offset into the section. If the | |
281 | symbol is in the .bss segment, we need to include the size of | |
282 | the data segment in the offset as well. Fortunately, we know | |
283 | that at this point the size of the data section is in the NLM | |
284 | header. */ | |
285 | if (((bfd_get_section_flags (abfd, bfd_get_section (sym)) | |
286 | & (SEC_CODE | SEC_DATA)) == 0) | |
287 | && ((bfd_get_section_flags (abfd, bfd_get_section (sym)) | |
288 | & SEC_ALLOC) != 0)) | |
289 | addend += nlm_fixed_header (abfd)->dataImageSize; | |
290 | ||
291 | if (addend != 0 | |
292 | && rel->howto != NULL | |
293 | && rel->howto->rightshift == 0 | |
294 | && rel->howto->size == 2 | |
295 | && rel->howto->bitsize == 32 | |
296 | && rel->howto->bitpos == 0 | |
297 | && rel->howto->partial_inplace | |
298 | && rel->howto->src_mask == 0xffffffff | |
299 | && rel->howto->dst_mask == 0xffffffff) | |
300 | { | |
301 | bfd_vma val; | |
302 | ||
303 | val = bfd_get_32 (abfd, (char *) data + rel->address - offset); | |
304 | val += addend; | |
305 | bfd_put_32 (abfd, val, (char *) data + rel->address - offset); | |
306 | rel->addend = 0; | |
307 | } | |
308 | ||
309 | /* NetWare uses a reloc with pcrel_offset set. We adjust | |
310 | pc_relative relocs accordingly. We are going to change the | |
311 | howto field, so we can only do this if the current one is | |
312 | compatible. We should check special_function here, but at | |
313 | the moment coff-i386 uses a special_function which does not | |
314 | affect what we are doing here. */ | |
315 | if (rel->howto != NULL | |
316 | && rel->howto->pc_relative | |
317 | && ! rel->howto->pcrel_offset | |
318 | && rel->howto->rightshift == 0 | |
319 | && rel->howto->size == 2 | |
320 | && rel->howto->bitsize == 32 | |
321 | && rel->howto->bitpos == 0 | |
322 | && rel->howto->partial_inplace | |
323 | && rel->howto->src_mask == 0xffffffff | |
324 | && rel->howto->dst_mask == 0xffffffff) | |
325 | { | |
326 | bfd_vma val; | |
327 | ||
328 | /* When pcrel_offset is not set, it means that the negative | |
329 | of the address of the memory location is stored in the | |
330 | memory location. We must add it back in. */ | |
331 | val = bfd_get_32 (abfd, (char *) data + rel->address - offset); | |
332 | val += rel->address; | |
333 | bfd_put_32 (abfd, val, (char *) data + rel->address - offset); | |
334 | ||
335 | rel->howto = &nlm_i386_pcrel_howto; | |
336 | } | |
337 | } | |
338 | ||
339 | return true; | |
340 | } | |
341 | ||
342 | static const struct nlm_backend_data nlm32_i386_backend = | |
343 | { | |
344 | bfd_arch_i386, | |
345 | nlm_i386_read_reloc, | |
346 | nlm_i386_write_reloc, | |
347 | nlm_i386_mangle_relocs | |
348 | }; | |
349 | ||
350 | #define TARGET_LITTLE_NAME "nlm32-i386" | |
351 | #define TARGET_LITTLE_SYM nlmNAME(i386_vec) | |
352 | #define TARGET_BACKEND_DATA &nlm32_i386_backend | |
353 | ||
354 | #include "nlm-target.h" |