Commit | Line | Data |
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1da177e4 LT |
1 | /* Kernel module help for PPC. |
2 | Copyright (C) 2001 Rusty Russell. | |
3 | ||
4 | This program is free software; you can redistribute it and/or modify | |
5 | it under the terms of the GNU General Public License as published by | |
6 | the Free Software Foundation; either version 2 of the License, or | |
7 | (at your option) any later version. | |
8 | ||
9 | This program is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | GNU General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU General Public License | |
15 | along with this program; if not, write to the Free Software | |
16 | Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
17 | */ | |
18 | #include <linux/module.h> | |
19 | #include <linux/moduleloader.h> | |
20 | #include <linux/elf.h> | |
21 | #include <linux/vmalloc.h> | |
22 | #include <linux/fs.h> | |
23 | #include <linux/string.h> | |
24 | #include <linux/kernel.h> | |
25 | #include <linux/cache.h> | |
73c9ceab | 26 | #include <linux/bug.h> |
eda09fbd | 27 | #include <linux/sort.h> |
1da177e4 | 28 | |
21c4ff80 BH |
29 | #include "setup.h" |
30 | ||
1da177e4 LT |
31 | #if 0 |
32 | #define DEBUGP printk | |
33 | #else | |
34 | #define DEBUGP(fmt , ...) | |
35 | #endif | |
36 | ||
37 | LIST_HEAD(module_bug_list); | |
38 | ||
39 | void *module_alloc(unsigned long size) | |
40 | { | |
41 | if (size == 0) | |
42 | return NULL; | |
43 | return vmalloc(size); | |
44 | } | |
45 | ||
46 | /* Free memory returned from module_alloc */ | |
47 | void module_free(struct module *mod, void *module_region) | |
48 | { | |
49 | vfree(module_region); | |
50 | /* FIXME: If module_region == mod->init_region, trim exception | |
51 | table entries. */ | |
52 | } | |
53 | ||
54 | /* Count how many different relocations (different symbol, different | |
55 | addend) */ | |
56 | static unsigned int count_relocs(const Elf32_Rela *rela, unsigned int num) | |
57 | { | |
eda09fbd EM |
58 | unsigned int i, r_info, r_addend, _count_relocs; |
59 | ||
60 | _count_relocs = 0; | |
61 | r_info = 0; | |
62 | r_addend = 0; | |
63 | for (i = 0; i < num; i++) | |
64 | /* Only count 24-bit relocs, others don't need stubs */ | |
65 | if (ELF32_R_TYPE(rela[i].r_info) == R_PPC_REL24 && | |
66 | (r_info != ELF32_R_SYM(rela[i].r_info) || | |
67 | r_addend != rela[i].r_addend)) { | |
68 | _count_relocs++; | |
69 | r_info = ELF32_R_SYM(rela[i].r_info); | |
70 | r_addend = rela[i].r_addend; | |
1da177e4 | 71 | } |
eda09fbd EM |
72 | |
73 | return _count_relocs; | |
74 | } | |
75 | ||
76 | static int relacmp(const void *_x, const void *_y) | |
77 | { | |
78 | const Elf32_Rela *x, *y; | |
79 | ||
80 | y = (Elf32_Rela *)_x; | |
81 | x = (Elf32_Rela *)_y; | |
82 | ||
83 | /* Compare the entire r_info (as opposed to ELF32_R_SYM(r_info) only) to | |
84 | * make the comparison cheaper/faster. It won't affect the sorting or | |
85 | * the counting algorithms' performance | |
86 | */ | |
87 | if (x->r_info < y->r_info) | |
88 | return -1; | |
89 | else if (x->r_info > y->r_info) | |
90 | return 1; | |
91 | else if (x->r_addend < y->r_addend) | |
92 | return -1; | |
93 | else if (x->r_addend > y->r_addend) | |
94 | return 1; | |
95 | else | |
96 | return 0; | |
97 | } | |
98 | ||
99 | static void relaswap(void *_x, void *_y, int size) | |
100 | { | |
101 | uint32_t *x, *y, tmp; | |
102 | int i; | |
103 | ||
104 | y = (uint32_t *)_x; | |
105 | x = (uint32_t *)_y; | |
106 | ||
107 | for (i = 0; i < sizeof(Elf32_Rela) / sizeof(uint32_t); i++) { | |
108 | tmp = x[i]; | |
109 | x[i] = y[i]; | |
110 | y[i] = tmp; | |
1da177e4 | 111 | } |
1da177e4 LT |
112 | } |
113 | ||
114 | /* Get the potential trampolines size required of the init and | |
115 | non-init sections */ | |
116 | static unsigned long get_plt_size(const Elf32_Ehdr *hdr, | |
117 | const Elf32_Shdr *sechdrs, | |
118 | const char *secstrings, | |
119 | int is_init) | |
120 | { | |
121 | unsigned long ret = 0; | |
122 | unsigned i; | |
123 | ||
124 | /* Everything marked ALLOC (this includes the exported | |
125 | symbols) */ | |
126 | for (i = 1; i < hdr->e_shnum; i++) { | |
127 | /* If it's called *.init*, and we're not init, we're | |
128 | not interested */ | |
129 | if ((strstr(secstrings + sechdrs[i].sh_name, ".init") != 0) | |
130 | != is_init) | |
131 | continue; | |
132 | ||
133 | /* We don't want to look at debug sections. */ | |
134 | if (strstr(secstrings + sechdrs[i].sh_name, ".debug") != 0) | |
135 | continue; | |
136 | ||
137 | if (sechdrs[i].sh_type == SHT_RELA) { | |
138 | DEBUGP("Found relocations in section %u\n", i); | |
139 | DEBUGP("Ptr: %p. Number: %u\n", | |
140 | (void *)hdr + sechdrs[i].sh_offset, | |
141 | sechdrs[i].sh_size / sizeof(Elf32_Rela)); | |
eda09fbd EM |
142 | |
143 | /* Sort the relocation information based on a symbol and | |
144 | * addend key. This is a stable O(n*log n) complexity | |
145 | * alogrithm but it will reduce the complexity of | |
146 | * count_relocs() to linear complexity O(n) | |
147 | */ | |
148 | sort((void *)hdr + sechdrs[i].sh_offset, | |
149 | sechdrs[i].sh_size / sizeof(Elf32_Rela), | |
150 | sizeof(Elf32_Rela), relacmp, relaswap); | |
151 | ||
1da177e4 LT |
152 | ret += count_relocs((void *)hdr |
153 | + sechdrs[i].sh_offset, | |
154 | sechdrs[i].sh_size | |
155 | / sizeof(Elf32_Rela)) | |
156 | * sizeof(struct ppc_plt_entry); | |
157 | } | |
158 | } | |
159 | ||
160 | return ret; | |
161 | } | |
162 | ||
163 | int module_frob_arch_sections(Elf32_Ehdr *hdr, | |
164 | Elf32_Shdr *sechdrs, | |
165 | char *secstrings, | |
166 | struct module *me) | |
167 | { | |
168 | unsigned int i; | |
169 | ||
170 | /* Find .plt and .init.plt sections */ | |
171 | for (i = 0; i < hdr->e_shnum; i++) { | |
172 | if (strcmp(secstrings + sechdrs[i].sh_name, ".init.plt") == 0) | |
173 | me->arch.init_plt_section = i; | |
174 | else if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0) | |
175 | me->arch.core_plt_section = i; | |
176 | } | |
177 | if (!me->arch.core_plt_section || !me->arch.init_plt_section) { | |
178 | printk("Module doesn't contain .plt or .init.plt sections.\n"); | |
179 | return -ENOEXEC; | |
180 | } | |
181 | ||
182 | /* Override their sizes */ | |
183 | sechdrs[me->arch.core_plt_section].sh_size | |
184 | = get_plt_size(hdr, sechdrs, secstrings, 0); | |
185 | sechdrs[me->arch.init_plt_section].sh_size | |
186 | = get_plt_size(hdr, sechdrs, secstrings, 1); | |
187 | return 0; | |
188 | } | |
189 | ||
190 | int apply_relocate(Elf32_Shdr *sechdrs, | |
191 | const char *strtab, | |
192 | unsigned int symindex, | |
193 | unsigned int relsec, | |
194 | struct module *module) | |
195 | { | |
196 | printk(KERN_ERR "%s: Non-ADD RELOCATION unsupported\n", | |
197 | module->name); | |
198 | return -ENOEXEC; | |
199 | } | |
200 | ||
201 | static inline int entry_matches(struct ppc_plt_entry *entry, Elf32_Addr val) | |
202 | { | |
203 | if (entry->jump[0] == 0x3d600000 + ((val + 0x8000) >> 16) | |
204 | && entry->jump[1] == 0x396b0000 + (val & 0xffff)) | |
205 | return 1; | |
206 | return 0; | |
207 | } | |
208 | ||
209 | /* Set up a trampoline in the PLT to bounce us to the distant function */ | |
210 | static uint32_t do_plt_call(void *location, | |
211 | Elf32_Addr val, | |
212 | Elf32_Shdr *sechdrs, | |
213 | struct module *mod) | |
214 | { | |
215 | struct ppc_plt_entry *entry; | |
216 | ||
217 | DEBUGP("Doing plt for call to 0x%x at 0x%x\n", val, (unsigned int)location); | |
218 | /* Init, or core PLT? */ | |
219 | if (location >= mod->module_core | |
220 | && location < mod->module_core + mod->core_size) | |
221 | entry = (void *)sechdrs[mod->arch.core_plt_section].sh_addr; | |
222 | else | |
223 | entry = (void *)sechdrs[mod->arch.init_plt_section].sh_addr; | |
224 | ||
225 | /* Find this entry, or if that fails, the next avail. entry */ | |
226 | while (entry->jump[0]) { | |
227 | if (entry_matches(entry, val)) return (uint32_t)entry; | |
228 | entry++; | |
229 | } | |
230 | ||
231 | /* Stolen from Paul Mackerras as well... */ | |
232 | entry->jump[0] = 0x3d600000+((val+0x8000)>>16); /* lis r11,sym@ha */ | |
233 | entry->jump[1] = 0x396b0000 + (val&0xffff); /* addi r11,r11,sym@l*/ | |
234 | entry->jump[2] = 0x7d6903a6; /* mtctr r11 */ | |
235 | entry->jump[3] = 0x4e800420; /* bctr */ | |
236 | ||
237 | DEBUGP("Initialized plt for 0x%x at %p\n", val, entry); | |
238 | return (uint32_t)entry; | |
239 | } | |
240 | ||
241 | int apply_relocate_add(Elf32_Shdr *sechdrs, | |
242 | const char *strtab, | |
243 | unsigned int symindex, | |
244 | unsigned int relsec, | |
245 | struct module *module) | |
246 | { | |
247 | unsigned int i; | |
248 | Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr; | |
249 | Elf32_Sym *sym; | |
250 | uint32_t *location; | |
251 | uint32_t value; | |
252 | ||
253 | DEBUGP("Applying ADD relocate section %u to %u\n", relsec, | |
254 | sechdrs[relsec].sh_info); | |
255 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) { | |
256 | /* This is where to make the change */ | |
257 | location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr | |
258 | + rela[i].r_offset; | |
259 | /* This is the symbol it is referring to. Note that all | |
260 | undefined symbols have been resolved. */ | |
261 | sym = (Elf32_Sym *)sechdrs[symindex].sh_addr | |
262 | + ELF32_R_SYM(rela[i].r_info); | |
263 | /* `Everything is relative'. */ | |
264 | value = sym->st_value + rela[i].r_addend; | |
265 | ||
266 | switch (ELF32_R_TYPE(rela[i].r_info)) { | |
267 | case R_PPC_ADDR32: | |
268 | /* Simply set it */ | |
269 | *(uint32_t *)location = value; | |
270 | break; | |
271 | ||
272 | case R_PPC_ADDR16_LO: | |
273 | /* Low half of the symbol */ | |
274 | *(uint16_t *)location = value; | |
275 | break; | |
9a3d6458 SV |
276 | |
277 | case R_PPC_ADDR16_HI: | |
278 | /* Higher half of the symbol */ | |
279 | *(uint16_t *)location = (value >> 16); | |
280 | break; | |
281 | ||
1da177e4 LT |
282 | case R_PPC_ADDR16_HA: |
283 | /* Sign-adjusted lower 16 bits: PPC ELF ABI says: | |
284 | (((x >> 16) + ((x & 0x8000) ? 1 : 0))) & 0xFFFF. | |
285 | This is the same, only sane. | |
286 | */ | |
287 | *(uint16_t *)location = (value + 0x8000) >> 16; | |
288 | break; | |
289 | ||
290 | case R_PPC_REL24: | |
291 | if ((int)(value - (uint32_t)location) < -0x02000000 | |
292 | || (int)(value - (uint32_t)location) >= 0x02000000) | |
293 | value = do_plt_call(location, value, | |
294 | sechdrs, module); | |
295 | ||
296 | /* Only replace bits 2 through 26 */ | |
297 | DEBUGP("REL24 value = %08X. location = %08X\n", | |
298 | value, (uint32_t)location); | |
299 | DEBUGP("Location before: %08X.\n", | |
300 | *(uint32_t *)location); | |
301 | *(uint32_t *)location | |
302 | = (*(uint32_t *)location & ~0x03fffffc) | |
303 | | ((value - (uint32_t)location) | |
304 | & 0x03fffffc); | |
305 | DEBUGP("Location after: %08X.\n", | |
306 | *(uint32_t *)location); | |
307 | DEBUGP("ie. jump to %08X+%08X = %08X\n", | |
308 | *(uint32_t *)location & 0x03fffffc, | |
309 | (uint32_t)location, | |
310 | (*(uint32_t *)location & 0x03fffffc) | |
311 | + (uint32_t)location); | |
312 | break; | |
313 | ||
314 | case R_PPC_REL32: | |
315 | /* 32-bit relative jump. */ | |
316 | *(uint32_t *)location = value - (uint32_t)location; | |
317 | break; | |
318 | ||
319 | default: | |
320 | printk("%s: unknown ADD relocation: %u\n", | |
321 | module->name, | |
322 | ELF32_R_TYPE(rela[i].r_info)); | |
323 | return -ENOEXEC; | |
324 | } | |
325 | } | |
326 | return 0; | |
327 | } | |
328 | ||
21c4ff80 BH |
329 | static const Elf_Shdr *find_section(const Elf_Ehdr *hdr, |
330 | const Elf_Shdr *sechdrs, | |
331 | const char *name) | |
332 | { | |
333 | char *secstrings; | |
334 | unsigned int i; | |
335 | ||
336 | secstrings = (char *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; | |
337 | for (i = 1; i < hdr->e_shnum; i++) | |
338 | if (strcmp(secstrings+sechdrs[i].sh_name, name) == 0) | |
339 | return &sechdrs[i]; | |
340 | return NULL; | |
341 | } | |
342 | ||
1da177e4 LT |
343 | int module_finalize(const Elf_Ehdr *hdr, |
344 | const Elf_Shdr *sechdrs, | |
345 | struct module *me) | |
346 | { | |
21c4ff80 | 347 | const Elf_Shdr *sect; |
73c9ceab | 348 | int err; |
1da177e4 | 349 | |
73c9ceab JF |
350 | err = module_bug_finalize(hdr, sechdrs, me); |
351 | if (err) /* never true, currently */ | |
352 | return err; | |
1da177e4 | 353 | |
21c4ff80 BH |
354 | /* Apply feature fixups */ |
355 | sect = find_section(hdr, sechdrs, "__ftr_fixup"); | |
356 | if (sect != NULL) | |
357 | do_feature_fixups(cur_cpu_spec->cpu_features, | |
358 | (void *)sect->sh_addr, | |
359 | (void *)sect->sh_addr + sect->sh_size); | |
360 | ||
1da177e4 LT |
361 | return 0; |
362 | } | |
363 | ||
364 | void module_arch_cleanup(struct module *mod) | |
365 | { | |
73c9ceab | 366 | module_bug_cleanup(mod); |
1da177e4 LT |
367 | } |
368 | ||
369 | struct bug_entry *module_find_bug(unsigned long bugaddr) | |
370 | { | |
371 | struct mod_arch_specific *mod; | |
372 | unsigned int i; | |
373 | struct bug_entry *bug; | |
374 | ||
375 | list_for_each_entry(mod, &module_bug_list, bug_list) { | |
376 | bug = mod->bug_table; | |
377 | for (i = 0; i < mod->num_bugs; ++i, ++bug) | |
378 | if (bugaddr == bug->bug_addr) | |
379 | return bug; | |
380 | } | |
381 | return NULL; | |
382 | } |