Commit | Line | Data |
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1da177e4 LT |
1 | /* Kernel module help for PPC64. |
2 | Copyright (C) 2001, 2003 Rusty Russell IBM Corporation. | |
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/elf.h> | |
20 | #include <linux/moduleloader.h> | |
21 | #include <linux/err.h> | |
22 | #include <linux/vmalloc.h> | |
73c9ceab | 23 | #include <linux/bug.h> |
1da177e4 | 24 | #include <asm/module.h> |
21c4ff80 | 25 | #include <asm/firmware.h> |
b7bcda63 | 26 | #include <asm/code-patching.h> |
eda09fbd | 27 | #include <linux/sort.h> |
21c4ff80 BH |
28 | |
29 | #include "setup.h" | |
1da177e4 LT |
30 | |
31 | /* FIXME: We don't do .init separately. To do this, we'd need to have | |
32 | a separate r2 value in the init and core section, and stub between | |
33 | them, too. | |
34 | ||
35 | Using a magic allocator which places modules within 32MB solves | |
36 | this, and makes other things simpler. Anton? | |
37 | --RR. */ | |
38 | #if 0 | |
39 | #define DEBUGP printk | |
40 | #else | |
41 | #define DEBUGP(fmt , ...) | |
42 | #endif | |
43 | ||
1da177e4 LT |
44 | /* Like PPC32, we need little trampolines to do > 24-bit jumps (into |
45 | the kernel itself). But on PPC64, these need to be used for every | |
46 | jump, actually, to reset r2 (TOC+0x8000). */ | |
47 | struct ppc64_stub_entry | |
48 | { | |
49 | /* 28 byte jump instruction sequence (7 instructions) */ | |
50 | unsigned char jump[28]; | |
51 | unsigned char unused[4]; | |
52 | /* Data for the above code */ | |
53 | struct ppc64_opd_entry opd; | |
54 | }; | |
55 | ||
56 | /* We use a stub to fix up r2 (TOC ptr) and to jump to the (external) | |
57 | function which may be more than 24-bits away. We could simply | |
58 | patch the new r2 value and function pointer into the stub, but it's | |
59 | significantly shorter to put these values at the end of the stub | |
60 | code, and patch the stub address (32-bits relative to the TOC ptr, | |
61 | r2) into the stub. */ | |
62 | static struct ppc64_stub_entry ppc64_stub = | |
63 | { .jump = { | |
64 | 0x3d, 0x82, 0x00, 0x00, /* addis r12,r2, <high> */ | |
65 | 0x39, 0x8c, 0x00, 0x00, /* addi r12,r12, <low> */ | |
66 | /* Save current r2 value in magic place on the stack. */ | |
67 | 0xf8, 0x41, 0x00, 0x28, /* std r2,40(r1) */ | |
68 | 0xe9, 0x6c, 0x00, 0x20, /* ld r11,32(r12) */ | |
69 | 0xe8, 0x4c, 0x00, 0x28, /* ld r2,40(r12) */ | |
70 | 0x7d, 0x69, 0x03, 0xa6, /* mtctr r11 */ | |
71 | 0x4e, 0x80, 0x04, 0x20 /* bctr */ | |
72 | } }; | |
73 | ||
74 | /* Count how many different 24-bit relocations (different symbol, | |
75 | different addend) */ | |
76 | static unsigned int count_relocs(const Elf64_Rela *rela, unsigned int num) | |
77 | { | |
eda09fbd | 78 | unsigned int i, r_info, r_addend, _count_relocs; |
1da177e4 LT |
79 | |
80 | /* FIXME: Only count external ones --RR */ | |
eda09fbd EM |
81 | _count_relocs = 0; |
82 | r_info = 0; | |
83 | r_addend = 0; | |
84 | for (i = 0; i < num; i++) | |
1da177e4 | 85 | /* Only count 24-bit relocs, others don't need stubs */ |
eda09fbd EM |
86 | if (ELF64_R_TYPE(rela[i].r_info) == R_PPC_REL24 && |
87 | (r_info != ELF64_R_SYM(rela[i].r_info) || | |
88 | r_addend != rela[i].r_addend)) { | |
89 | _count_relocs++; | |
90 | r_info = ELF64_R_SYM(rela[i].r_info); | |
91 | r_addend = rela[i].r_addend; | |
1da177e4 | 92 | } |
eda09fbd EM |
93 | |
94 | return _count_relocs; | |
1da177e4 LT |
95 | } |
96 | ||
eda09fbd EM |
97 | static int relacmp(const void *_x, const void *_y) |
98 | { | |
99 | const Elf64_Rela *x, *y; | |
100 | ||
101 | y = (Elf64_Rela *)_x; | |
102 | x = (Elf64_Rela *)_y; | |
103 | ||
104 | /* Compare the entire r_info (as opposed to ELF64_R_SYM(r_info) only) to | |
105 | * make the comparison cheaper/faster. It won't affect the sorting or | |
106 | * the counting algorithms' performance | |
107 | */ | |
108 | if (x->r_info < y->r_info) | |
109 | return -1; | |
110 | else if (x->r_info > y->r_info) | |
111 | return 1; | |
112 | else if (x->r_addend < y->r_addend) | |
113 | return -1; | |
114 | else if (x->r_addend > y->r_addend) | |
115 | return 1; | |
116 | else | |
117 | return 0; | |
118 | } | |
119 | ||
120 | static void relaswap(void *_x, void *_y, int size) | |
121 | { | |
122 | uint64_t *x, *y, tmp; | |
123 | int i; | |
124 | ||
125 | y = (uint64_t *)_x; | |
126 | x = (uint64_t *)_y; | |
127 | ||
128 | for (i = 0; i < sizeof(Elf64_Rela) / sizeof(uint64_t); i++) { | |
129 | tmp = x[i]; | |
130 | x[i] = y[i]; | |
131 | y[i] = tmp; | |
132 | } | |
133 | } | |
134 | ||
1da177e4 LT |
135 | /* Get size of potential trampolines required. */ |
136 | static unsigned long get_stubs_size(const Elf64_Ehdr *hdr, | |
137 | const Elf64_Shdr *sechdrs) | |
138 | { | |
139 | /* One extra reloc so it's always 0-funcaddr terminated */ | |
140 | unsigned long relocs = 1; | |
141 | unsigned i; | |
142 | ||
143 | /* Every relocated section... */ | |
144 | for (i = 1; i < hdr->e_shnum; i++) { | |
145 | if (sechdrs[i].sh_type == SHT_RELA) { | |
146 | DEBUGP("Found relocations in section %u\n", i); | |
147 | DEBUGP("Ptr: %p. Number: %lu\n", | |
148 | (void *)sechdrs[i].sh_addr, | |
149 | sechdrs[i].sh_size / sizeof(Elf64_Rela)); | |
eda09fbd EM |
150 | |
151 | /* Sort the relocation information based on a symbol and | |
152 | * addend key. This is a stable O(n*log n) complexity | |
153 | * alogrithm but it will reduce the complexity of | |
154 | * count_relocs() to linear complexity O(n) | |
155 | */ | |
156 | sort((void *)sechdrs[i].sh_addr, | |
157 | sechdrs[i].sh_size / sizeof(Elf64_Rela), | |
158 | sizeof(Elf64_Rela), relacmp, relaswap); | |
159 | ||
1da177e4 LT |
160 | relocs += count_relocs((void *)sechdrs[i].sh_addr, |
161 | sechdrs[i].sh_size | |
162 | / sizeof(Elf64_Rela)); | |
163 | } | |
164 | } | |
165 | ||
166 | DEBUGP("Looks like a total of %lu stubs, max\n", relocs); | |
167 | return relocs * sizeof(struct ppc64_stub_entry); | |
168 | } | |
169 | ||
170 | static void dedotify_versions(struct modversion_info *vers, | |
171 | unsigned long size) | |
172 | { | |
173 | struct modversion_info *end; | |
174 | ||
175 | for (end = (void *)vers + size; vers < end; vers++) | |
176 | if (vers->name[0] == '.') | |
177 | memmove(vers->name, vers->name+1, strlen(vers->name)); | |
178 | } | |
179 | ||
180 | /* Undefined symbols which refer to .funcname, hack to funcname */ | |
181 | static void dedotify(Elf64_Sym *syms, unsigned int numsyms, char *strtab) | |
182 | { | |
183 | unsigned int i; | |
184 | ||
185 | for (i = 1; i < numsyms; i++) { | |
186 | if (syms[i].st_shndx == SHN_UNDEF) { | |
187 | char *name = strtab + syms[i].st_name; | |
188 | if (name[0] == '.') | |
189 | memmove(name, name+1, strlen(name)); | |
190 | } | |
191 | } | |
192 | } | |
193 | ||
194 | int module_frob_arch_sections(Elf64_Ehdr *hdr, | |
195 | Elf64_Shdr *sechdrs, | |
196 | char *secstrings, | |
197 | struct module *me) | |
198 | { | |
199 | unsigned int i; | |
200 | ||
201 | /* Find .toc and .stubs sections, symtab and strtab */ | |
202 | for (i = 1; i < hdr->e_shnum; i++) { | |
203 | char *p; | |
204 | if (strcmp(secstrings + sechdrs[i].sh_name, ".stubs") == 0) | |
205 | me->arch.stubs_section = i; | |
206 | else if (strcmp(secstrings + sechdrs[i].sh_name, ".toc") == 0) | |
207 | me->arch.toc_section = i; | |
208 | else if (strcmp(secstrings+sechdrs[i].sh_name,"__versions")==0) | |
209 | dedotify_versions((void *)hdr + sechdrs[i].sh_offset, | |
210 | sechdrs[i].sh_size); | |
211 | ||
212 | /* We don't handle .init for the moment: rename to _init */ | |
213 | while ((p = strstr(secstrings + sechdrs[i].sh_name, ".init"))) | |
214 | p[0] = '_'; | |
215 | ||
216 | if (sechdrs[i].sh_type == SHT_SYMTAB) | |
217 | dedotify((void *)hdr + sechdrs[i].sh_offset, | |
218 | sechdrs[i].sh_size / sizeof(Elf64_Sym), | |
219 | (void *)hdr | |
220 | + sechdrs[sechdrs[i].sh_link].sh_offset); | |
221 | } | |
f749edae AM |
222 | |
223 | if (!me->arch.stubs_section) { | |
224 | printk("%s: doesn't contain .stubs.\n", me->name); | |
1da177e4 LT |
225 | return -ENOEXEC; |
226 | } | |
227 | ||
f749edae AM |
228 | /* If we don't have a .toc, just use .stubs. We need to set r2 |
229 | to some reasonable value in case the module calls out to | |
230 | other functions via a stub, or if a function pointer escapes | |
231 | the module by some means. */ | |
232 | if (!me->arch.toc_section) | |
233 | me->arch.toc_section = me->arch.stubs_section; | |
234 | ||
1da177e4 LT |
235 | /* Override the stubs size */ |
236 | sechdrs[me->arch.stubs_section].sh_size = get_stubs_size(hdr, sechdrs); | |
237 | return 0; | |
238 | } | |
239 | ||
240 | int apply_relocate(Elf64_Shdr *sechdrs, | |
241 | const char *strtab, | |
242 | unsigned int symindex, | |
243 | unsigned int relsec, | |
244 | struct module *me) | |
245 | { | |
246 | printk(KERN_ERR "%s: Non-ADD RELOCATION unsupported\n", me->name); | |
247 | return -ENOEXEC; | |
248 | } | |
249 | ||
250 | /* r2 is the TOC pointer: it actually points 0x8000 into the TOC (this | |
251 | gives the value maximum span in an instruction which uses a signed | |
252 | offset) */ | |
253 | static inline unsigned long my_r2(Elf64_Shdr *sechdrs, struct module *me) | |
254 | { | |
255 | return sechdrs[me->arch.toc_section].sh_addr + 0x8000; | |
256 | } | |
257 | ||
258 | /* Both low and high 16 bits are added as SIGNED additions, so if low | |
259 | 16 bits has high bit set, high 16 bits must be adjusted. These | |
260 | macros do that (stolen from binutils). */ | |
261 | #define PPC_LO(v) ((v) & 0xffff) | |
262 | #define PPC_HI(v) (((v) >> 16) & 0xffff) | |
263 | #define PPC_HA(v) PPC_HI ((v) + 0x8000) | |
264 | ||
265 | /* Patch stub to reference function and correct r2 value. */ | |
266 | static inline int create_stub(Elf64_Shdr *sechdrs, | |
267 | struct ppc64_stub_entry *entry, | |
268 | struct ppc64_opd_entry *opd, | |
269 | struct module *me) | |
270 | { | |
271 | Elf64_Half *loc1, *loc2; | |
272 | long reladdr; | |
273 | ||
274 | *entry = ppc64_stub; | |
275 | ||
276 | loc1 = (Elf64_Half *)&entry->jump[2]; | |
277 | loc2 = (Elf64_Half *)&entry->jump[6]; | |
278 | ||
279 | /* Stub uses address relative to r2. */ | |
280 | reladdr = (unsigned long)entry - my_r2(sechdrs, me); | |
281 | if (reladdr > 0x7FFFFFFF || reladdr < -(0x80000000L)) { | |
282 | printk("%s: Address %p of stub out of range of %p.\n", | |
283 | me->name, (void *)reladdr, (void *)my_r2); | |
284 | return 0; | |
285 | } | |
286 | DEBUGP("Stub %p get data from reladdr %li\n", entry, reladdr); | |
287 | ||
288 | *loc1 = PPC_HA(reladdr); | |
289 | *loc2 = PPC_LO(reladdr); | |
290 | entry->opd.funcaddr = opd->funcaddr; | |
291 | entry->opd.r2 = opd->r2; | |
292 | return 1; | |
293 | } | |
294 | ||
295 | /* Create stub to jump to function described in this OPD: we need the | |
296 | stub to set up the TOC ptr (r2) for the function. */ | |
297 | static unsigned long stub_for_addr(Elf64_Shdr *sechdrs, | |
298 | unsigned long opdaddr, | |
299 | struct module *me) | |
300 | { | |
301 | struct ppc64_stub_entry *stubs; | |
302 | struct ppc64_opd_entry *opd = (void *)opdaddr; | |
303 | unsigned int i, num_stubs; | |
304 | ||
305 | num_stubs = sechdrs[me->arch.stubs_section].sh_size / sizeof(*stubs); | |
306 | ||
307 | /* Find this stub, or if that fails, the next avail. entry */ | |
308 | stubs = (void *)sechdrs[me->arch.stubs_section].sh_addr; | |
309 | for (i = 0; stubs[i].opd.funcaddr; i++) { | |
310 | BUG_ON(i >= num_stubs); | |
311 | ||
312 | if (stubs[i].opd.funcaddr == opd->funcaddr) | |
313 | return (unsigned long)&stubs[i]; | |
314 | } | |
315 | ||
316 | if (!create_stub(sechdrs, &stubs[i], opd, me)) | |
317 | return 0; | |
318 | ||
319 | return (unsigned long)&stubs[i]; | |
320 | } | |
321 | ||
322 | /* We expect a noop next: if it is, replace it with instruction to | |
323 | restore r2. */ | |
324 | static int restore_r2(u32 *instruction, struct module *me) | |
325 | { | |
b7bcda63 | 326 | if (*instruction != PPC_NOP_INSTR) { |
1da177e4 LT |
327 | printk("%s: Expect noop after relocate, got %08x\n", |
328 | me->name, *instruction); | |
329 | return 0; | |
330 | } | |
331 | *instruction = 0xe8410028; /* ld r2,40(r1) */ | |
332 | return 1; | |
333 | } | |
334 | ||
335 | int apply_relocate_add(Elf64_Shdr *sechdrs, | |
336 | const char *strtab, | |
337 | unsigned int symindex, | |
338 | unsigned int relsec, | |
339 | struct module *me) | |
340 | { | |
341 | unsigned int i; | |
342 | Elf64_Rela *rela = (void *)sechdrs[relsec].sh_addr; | |
343 | Elf64_Sym *sym; | |
344 | unsigned long *location; | |
345 | unsigned long value; | |
346 | ||
347 | DEBUGP("Applying ADD relocate section %u to %u\n", relsec, | |
348 | sechdrs[relsec].sh_info); | |
349 | for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) { | |
350 | /* This is where to make the change */ | |
351 | location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr | |
352 | + rela[i].r_offset; | |
353 | /* This is the symbol it is referring to */ | |
354 | sym = (Elf64_Sym *)sechdrs[symindex].sh_addr | |
355 | + ELF64_R_SYM(rela[i].r_info); | |
356 | ||
357 | DEBUGP("RELOC at %p: %li-type as %s (%lu) + %li\n", | |
358 | location, (long)ELF64_R_TYPE(rela[i].r_info), | |
359 | strtab + sym->st_name, (unsigned long)sym->st_value, | |
360 | (long)rela[i].r_addend); | |
361 | ||
362 | /* `Everything is relative'. */ | |
363 | value = sym->st_value + rela[i].r_addend; | |
364 | ||
365 | switch (ELF64_R_TYPE(rela[i].r_info)) { | |
366 | case R_PPC64_ADDR32: | |
367 | /* Simply set it */ | |
368 | *(u32 *)location = value; | |
369 | break; | |
eda09fbd | 370 | |
1da177e4 LT |
371 | case R_PPC64_ADDR64: |
372 | /* Simply set it */ | |
373 | *(unsigned long *)location = value; | |
374 | break; | |
375 | ||
376 | case R_PPC64_TOC: | |
377 | *(unsigned long *)location = my_r2(sechdrs, me); | |
378 | break; | |
379 | ||
9149ccfa | 380 | case R_PPC64_TOC16: |
f749edae | 381 | /* Subtract TOC pointer */ |
9149ccfa PB |
382 | value -= my_r2(sechdrs, me); |
383 | if (value + 0x8000 > 0xffff) { | |
384 | printk("%s: bad TOC16 relocation (%lu)\n", | |
385 | me->name, value); | |
386 | return -ENOEXEC; | |
387 | } | |
388 | *((uint16_t *) location) | |
389 | = (*((uint16_t *) location) & ~0xffff) | |
390 | | (value & 0xffff); | |
391 | break; | |
392 | ||
1da177e4 | 393 | case R_PPC64_TOC16_DS: |
f749edae | 394 | /* Subtract TOC pointer */ |
1da177e4 LT |
395 | value -= my_r2(sechdrs, me); |
396 | if ((value & 3) != 0 || value + 0x8000 > 0xffff) { | |
397 | printk("%s: bad TOC16_DS relocation (%lu)\n", | |
398 | me->name, value); | |
399 | return -ENOEXEC; | |
400 | } | |
401 | *((uint16_t *) location) | |
402 | = (*((uint16_t *) location) & ~0xfffc) | |
403 | | (value & 0xfffc); | |
404 | break; | |
405 | ||
406 | case R_PPC_REL24: | |
407 | /* FIXME: Handle weak symbols here --RR */ | |
408 | if (sym->st_shndx == SHN_UNDEF) { | |
409 | /* External: go via stub */ | |
410 | value = stub_for_addr(sechdrs, value, me); | |
411 | if (!value) | |
412 | return -ENOENT; | |
413 | if (!restore_r2((u32 *)location + 1, me)) | |
414 | return -ENOEXEC; | |
415 | } | |
416 | ||
417 | /* Convert value to relative */ | |
418 | value -= (unsigned long)location; | |
419 | if (value + 0x2000000 > 0x3ffffff || (value & 3) != 0){ | |
420 | printk("%s: REL24 %li out of range!\n", | |
421 | me->name, (long int)value); | |
422 | return -ENOEXEC; | |
423 | } | |
424 | ||
425 | /* Only replace bits 2 through 26 */ | |
eda09fbd | 426 | *(uint32_t *)location |
1da177e4 LT |
427 | = (*(uint32_t *)location & ~0x03fffffc) |
428 | | (value & 0x03fffffc); | |
429 | break; | |
430 | ||
21c4ff80 BH |
431 | case R_PPC64_REL64: |
432 | /* 64 bits relative (used by features fixups) */ | |
433 | *location = value - (unsigned long)location; | |
434 | break; | |
435 | ||
1da177e4 LT |
436 | default: |
437 | printk("%s: Unknown ADD relocation: %lu\n", | |
438 | me->name, | |
439 | (unsigned long)ELF64_R_TYPE(rela[i].r_info)); | |
440 | return -ENOEXEC; | |
441 | } | |
442 | } | |
443 | ||
444 | return 0; | |
445 | } |