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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Kernel module help for s390.
4 *
5 * S390 version
6 * Copyright IBM Corp. 2002, 2003
7 * Author(s): Arnd Bergmann (arndb@de.ibm.com)
8 * Martin Schwidefsky (schwidefsky@de.ibm.com)
9 *
10 * based on i386 version
11 * Copyright (C) 2001 Rusty Russell.
12 */
13#include <linux/module.h>
14#include <linux/elf.h>
15#include <linux/vmalloc.h>
16#include <linux/fs.h>
17#include <linux/ftrace.h>
18#include <linux/string.h>
19#include <linux/kernel.h>
20#include <linux/kasan.h>
21#include <linux/moduleloader.h>
22#include <linux/bug.h>
23#include <linux/memory.h>
24#include <linux/execmem.h>
25#include <asm/alternative.h>
26#include <asm/nospec-branch.h>
27#include <asm/facility.h>
28#include <asm/ftrace.lds.h>
29#include <asm/set_memory.h>
30#include <asm/setup.h>
31
32#if 0
33#define DEBUGP printk
34#else
35#define DEBUGP(fmt , ...)
36#endif
37
38#define PLT_ENTRY_SIZE 22
39
40#ifdef CONFIG_FUNCTION_TRACER
41void module_arch_cleanup(struct module *mod)
42{
43 execmem_free(mod->arch.trampolines_start);
44}
45#endif
46
47void module_arch_freeing_init(struct module *mod)
48{
49 if (is_livepatch_module(mod) &&
50 mod->state == MODULE_STATE_LIVE)
51 return;
52
53 vfree(mod->arch.syminfo);
54 mod->arch.syminfo = NULL;
55}
56
57static void check_rela(Elf_Rela *rela, struct module *me)
58{
59 struct mod_arch_syminfo *info;
60
61 info = me->arch.syminfo + ELF_R_SYM (rela->r_info);
62 switch (ELF_R_TYPE (rela->r_info)) {
63 case R_390_GOT12: /* 12 bit GOT offset. */
64 case R_390_GOT16: /* 16 bit GOT offset. */
65 case R_390_GOT20: /* 20 bit GOT offset. */
66 case R_390_GOT32: /* 32 bit GOT offset. */
67 case R_390_GOT64: /* 64 bit GOT offset. */
68 case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */
69 case R_390_GOTPLT12: /* 12 bit offset to jump slot. */
70 case R_390_GOTPLT16: /* 16 bit offset to jump slot. */
71 case R_390_GOTPLT20: /* 20 bit offset to jump slot. */
72 case R_390_GOTPLT32: /* 32 bit offset to jump slot. */
73 case R_390_GOTPLT64: /* 64 bit offset to jump slot. */
74 case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */
75 if (info->got_offset == -1UL) {
76 info->got_offset = me->arch.got_size;
77 me->arch.got_size += sizeof(void*);
78 }
79 break;
80 case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */
81 case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */
82 case R_390_PLT32: /* 32 bit PC relative PLT address. */
83 case R_390_PLT64: /* 64 bit PC relative PLT address. */
84 case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */
85 case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */
86 case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */
87 if (info->plt_offset == -1UL) {
88 info->plt_offset = me->arch.plt_size;
89 me->arch.plt_size += PLT_ENTRY_SIZE;
90 }
91 break;
92 case R_390_COPY:
93 case R_390_GLOB_DAT:
94 case R_390_JMP_SLOT:
95 case R_390_RELATIVE:
96 /* Only needed if we want to support loading of
97 modules linked with -shared. */
98 break;
99 }
100}
101
102/*
103 * Account for GOT and PLT relocations. We can't add sections for
104 * got and plt but we can increase the core module size.
105 */
106int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
107 char *secstrings, struct module *me)
108{
109 Elf_Shdr *symtab;
110 Elf_Sym *symbols;
111 Elf_Rela *rela;
112 char *strings;
113 int nrela, i, j;
114 struct module_memory *mod_mem;
115
116 /* Find symbol table and string table. */
117 symtab = NULL;
118 for (i = 0; i < hdr->e_shnum; i++)
119 switch (sechdrs[i].sh_type) {
120 case SHT_SYMTAB:
121 symtab = sechdrs + i;
122 break;
123 }
124 if (!symtab) {
125 printk(KERN_ERR "module %s: no symbol table\n", me->name);
126 return -ENOEXEC;
127 }
128
129 /* Allocate one syminfo structure per symbol. */
130 me->arch.nsyms = symtab->sh_size / sizeof(Elf_Sym);
131 me->arch.syminfo = vmalloc(array_size(sizeof(struct mod_arch_syminfo),
132 me->arch.nsyms));
133 if (!me->arch.syminfo)
134 return -ENOMEM;
135 symbols = (void *) hdr + symtab->sh_offset;
136 strings = (void *) hdr + sechdrs[symtab->sh_link].sh_offset;
137 for (i = 0; i < me->arch.nsyms; i++) {
138 if (symbols[i].st_shndx == SHN_UNDEF &&
139 strcmp(strings + symbols[i].st_name,
140 "_GLOBAL_OFFSET_TABLE_") == 0)
141 /* "Define" it as absolute. */
142 symbols[i].st_shndx = SHN_ABS;
143 me->arch.syminfo[i].got_offset = -1UL;
144 me->arch.syminfo[i].plt_offset = -1UL;
145 me->arch.syminfo[i].got_initialized = 0;
146 me->arch.syminfo[i].plt_initialized = 0;
147 }
148
149 /* Search for got/plt relocations. */
150 me->arch.got_size = me->arch.plt_size = 0;
151 for (i = 0; i < hdr->e_shnum; i++) {
152 if (sechdrs[i].sh_type != SHT_RELA)
153 continue;
154 nrela = sechdrs[i].sh_size / sizeof(Elf_Rela);
155 rela = (void *) hdr + sechdrs[i].sh_offset;
156 for (j = 0; j < nrela; j++)
157 check_rela(rela + j, me);
158 }
159
160 /* Increase core size by size of got & plt and set start
161 offsets for got and plt. */
162 mod_mem = &me->mem[MOD_TEXT];
163 mod_mem->size = ALIGN(mod_mem->size, 4);
164 me->arch.got_offset = mod_mem->size;
165 mod_mem->size += me->arch.got_size;
166 me->arch.plt_offset = mod_mem->size;
167 if (me->arch.plt_size) {
168 if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_disable)
169 me->arch.plt_size += PLT_ENTRY_SIZE;
170 mod_mem->size += me->arch.plt_size;
171 }
172 return 0;
173}
174
175static int apply_rela_bits(Elf_Addr loc, Elf_Addr val,
176 int sign, int bits, int shift,
177 void *(*write)(void *dest, const void *src, size_t len))
178{
179 unsigned long umax;
180 long min, max;
181 void *dest = (void *)loc;
182
183 if (val & ((1UL << shift) - 1))
184 return -ENOEXEC;
185 if (sign) {
186 val = (Elf_Addr)(((long) val) >> shift);
187 min = -(1L << (bits - 1));
188 max = (1L << (bits - 1)) - 1;
189 if ((long) val < min || (long) val > max)
190 return -ENOEXEC;
191 } else {
192 val >>= shift;
193 umax = ((1UL << (bits - 1)) << 1) - 1;
194 if ((unsigned long) val > umax)
195 return -ENOEXEC;
196 }
197
198 if (bits == 8) {
199 unsigned char tmp = val;
200 write(dest, &tmp, 1);
201 } else if (bits == 12) {
202 unsigned short tmp = (val & 0xfff) |
203 (*(unsigned short *) loc & 0xf000);
204 write(dest, &tmp, 2);
205 } else if (bits == 16) {
206 unsigned short tmp = val;
207 write(dest, &tmp, 2);
208 } else if (bits == 20) {
209 unsigned int tmp = (val & 0xfff) << 16 |
210 (val & 0xff000) >> 4 | (*(unsigned int *) loc & 0xf00000ff);
211 write(dest, &tmp, 4);
212 } else if (bits == 32) {
213 unsigned int tmp = val;
214 write(dest, &tmp, 4);
215 } else if (bits == 64) {
216 unsigned long tmp = val;
217 write(dest, &tmp, 8);
218 }
219 return 0;
220}
221
222static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
223 const char *strtab, struct module *me,
224 void *(*write)(void *dest, const void *src, size_t len))
225{
226 struct mod_arch_syminfo *info;
227 Elf_Addr loc, val;
228 int r_type, r_sym;
229 int rc = -ENOEXEC;
230
231 /* This is where to make the change */
232 loc = base + rela->r_offset;
233 /* This is the symbol it is referring to. Note that all
234 undefined symbols have been resolved. */
235 r_sym = ELF_R_SYM(rela->r_info);
236 r_type = ELF_R_TYPE(rela->r_info);
237 info = me->arch.syminfo + r_sym;
238 val = symtab[r_sym].st_value;
239
240 switch (r_type) {
241 case R_390_NONE: /* No relocation. */
242 rc = 0;
243 break;
244 case R_390_8: /* Direct 8 bit. */
245 case R_390_12: /* Direct 12 bit. */
246 case R_390_16: /* Direct 16 bit. */
247 case R_390_20: /* Direct 20 bit. */
248 case R_390_32: /* Direct 32 bit. */
249 case R_390_64: /* Direct 64 bit. */
250 val += rela->r_addend;
251 if (r_type == R_390_8)
252 rc = apply_rela_bits(loc, val, 0, 8, 0, write);
253 else if (r_type == R_390_12)
254 rc = apply_rela_bits(loc, val, 0, 12, 0, write);
255 else if (r_type == R_390_16)
256 rc = apply_rela_bits(loc, val, 0, 16, 0, write);
257 else if (r_type == R_390_20)
258 rc = apply_rela_bits(loc, val, 1, 20, 0, write);
259 else if (r_type == R_390_32)
260 rc = apply_rela_bits(loc, val, 0, 32, 0, write);
261 else if (r_type == R_390_64)
262 rc = apply_rela_bits(loc, val, 0, 64, 0, write);
263 break;
264 case R_390_PC16: /* PC relative 16 bit. */
265 case R_390_PC16DBL: /* PC relative 16 bit shifted by 1. */
266 case R_390_PC32DBL: /* PC relative 32 bit shifted by 1. */
267 case R_390_PC32: /* PC relative 32 bit. */
268 case R_390_PC64: /* PC relative 64 bit. */
269 val += rela->r_addend - loc;
270 if (r_type == R_390_PC16)
271 rc = apply_rela_bits(loc, val, 1, 16, 0, write);
272 else if (r_type == R_390_PC16DBL)
273 rc = apply_rela_bits(loc, val, 1, 16, 1, write);
274 else if (r_type == R_390_PC32DBL)
275 rc = apply_rela_bits(loc, val, 1, 32, 1, write);
276 else if (r_type == R_390_PC32)
277 rc = apply_rela_bits(loc, val, 1, 32, 0, write);
278 else if (r_type == R_390_PC64)
279 rc = apply_rela_bits(loc, val, 1, 64, 0, write);
280 break;
281 case R_390_GOT12: /* 12 bit GOT offset. */
282 case R_390_GOT16: /* 16 bit GOT offset. */
283 case R_390_GOT20: /* 20 bit GOT offset. */
284 case R_390_GOT32: /* 32 bit GOT offset. */
285 case R_390_GOT64: /* 64 bit GOT offset. */
286 case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */
287 case R_390_GOTPLT12: /* 12 bit offset to jump slot. */
288 case R_390_GOTPLT20: /* 20 bit offset to jump slot. */
289 case R_390_GOTPLT16: /* 16 bit offset to jump slot. */
290 case R_390_GOTPLT32: /* 32 bit offset to jump slot. */
291 case R_390_GOTPLT64: /* 64 bit offset to jump slot. */
292 case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */
293 if (info->got_initialized == 0) {
294 Elf_Addr *gotent = me->mem[MOD_TEXT].base +
295 me->arch.got_offset +
296 info->got_offset;
297
298 write(gotent, &val, sizeof(*gotent));
299 info->got_initialized = 1;
300 }
301 val = info->got_offset + rela->r_addend;
302 if (r_type == R_390_GOT12 ||
303 r_type == R_390_GOTPLT12)
304 rc = apply_rela_bits(loc, val, 0, 12, 0, write);
305 else if (r_type == R_390_GOT16 ||
306 r_type == R_390_GOTPLT16)
307 rc = apply_rela_bits(loc, val, 0, 16, 0, write);
308 else if (r_type == R_390_GOT20 ||
309 r_type == R_390_GOTPLT20)
310 rc = apply_rela_bits(loc, val, 1, 20, 0, write);
311 else if (r_type == R_390_GOT32 ||
312 r_type == R_390_GOTPLT32)
313 rc = apply_rela_bits(loc, val, 0, 32, 0, write);
314 else if (r_type == R_390_GOT64 ||
315 r_type == R_390_GOTPLT64)
316 rc = apply_rela_bits(loc, val, 0, 64, 0, write);
317 else if (r_type == R_390_GOTENT ||
318 r_type == R_390_GOTPLTENT) {
319 val += (Elf_Addr)me->mem[MOD_TEXT].base +
320 me->arch.got_offset - loc;
321 rc = apply_rela_bits(loc, val, 1, 32, 1, write);
322 }
323 break;
324 case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */
325 case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */
326 case R_390_PLT32: /* 32 bit PC relative PLT address. */
327 case R_390_PLT64: /* 64 bit PC relative PLT address. */
328 case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */
329 case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */
330 case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */
331 if (info->plt_initialized == 0) {
332 unsigned char insn[PLT_ENTRY_SIZE];
333 char *plt_base;
334 char *ip;
335
336 plt_base = me->mem[MOD_TEXT].base + me->arch.plt_offset;
337 ip = plt_base + info->plt_offset;
338 *(int *)insn = 0x0d10e310; /* basr 1,0 */
339 *(int *)&insn[4] = 0x100c0004; /* lg 1,12(1) */
340 if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_disable) {
341 char *jump_r1;
342
343 jump_r1 = plt_base + me->arch.plt_size -
344 PLT_ENTRY_SIZE;
345 /* brcl 0xf,__jump_r1 */
346 *(short *)&insn[8] = 0xc0f4;
347 *(int *)&insn[10] = (jump_r1 - (ip + 8)) / 2;
348 } else {
349 *(int *)&insn[8] = 0x07f10000; /* br %r1 */
350 }
351 *(long *)&insn[14] = val;
352
353 write(ip, insn, sizeof(insn));
354 info->plt_initialized = 1;
355 }
356 if (r_type == R_390_PLTOFF16 ||
357 r_type == R_390_PLTOFF32 ||
358 r_type == R_390_PLTOFF64)
359 val = me->arch.plt_offset - me->arch.got_offset +
360 info->plt_offset + rela->r_addend;
361 else {
362 if (!((r_type == R_390_PLT16DBL &&
363 val - loc + 0xffffUL < 0x1ffffeUL) ||
364 (r_type == R_390_PLT32DBL &&
365 val - loc + 0xffffffffULL < 0x1fffffffeULL)))
366 val = (Elf_Addr) me->mem[MOD_TEXT].base +
367 me->arch.plt_offset +
368 info->plt_offset;
369 val += rela->r_addend - loc;
370 }
371 if (r_type == R_390_PLT16DBL)
372 rc = apply_rela_bits(loc, val, 1, 16, 1, write);
373 else if (r_type == R_390_PLTOFF16)
374 rc = apply_rela_bits(loc, val, 0, 16, 0, write);
375 else if (r_type == R_390_PLT32DBL)
376 rc = apply_rela_bits(loc, val, 1, 32, 1, write);
377 else if (r_type == R_390_PLT32 ||
378 r_type == R_390_PLTOFF32)
379 rc = apply_rela_bits(loc, val, 0, 32, 0, write);
380 else if (r_type == R_390_PLT64 ||
381 r_type == R_390_PLTOFF64)
382 rc = apply_rela_bits(loc, val, 0, 64, 0, write);
383 break;
384 case R_390_GOTOFF16: /* 16 bit offset to GOT. */
385 case R_390_GOTOFF32: /* 32 bit offset to GOT. */
386 case R_390_GOTOFF64: /* 64 bit offset to GOT. */
387 val = val + rela->r_addend -
388 ((Elf_Addr) me->mem[MOD_TEXT].base + me->arch.got_offset);
389 if (r_type == R_390_GOTOFF16)
390 rc = apply_rela_bits(loc, val, 0, 16, 0, write);
391 else if (r_type == R_390_GOTOFF32)
392 rc = apply_rela_bits(loc, val, 0, 32, 0, write);
393 else if (r_type == R_390_GOTOFF64)
394 rc = apply_rela_bits(loc, val, 0, 64, 0, write);
395 break;
396 case R_390_GOTPC: /* 32 bit PC relative offset to GOT. */
397 case R_390_GOTPCDBL: /* 32 bit PC rel. off. to GOT shifted by 1. */
398 val = (Elf_Addr) me->mem[MOD_TEXT].base + me->arch.got_offset +
399 rela->r_addend - loc;
400 if (r_type == R_390_GOTPC)
401 rc = apply_rela_bits(loc, val, 1, 32, 0, write);
402 else if (r_type == R_390_GOTPCDBL)
403 rc = apply_rela_bits(loc, val, 1, 32, 1, write);
404 break;
405 case R_390_COPY:
406 case R_390_GLOB_DAT: /* Create GOT entry. */
407 case R_390_JMP_SLOT: /* Create PLT entry. */
408 case R_390_RELATIVE: /* Adjust by program base. */
409 /* Only needed if we want to support loading of
410 modules linked with -shared. */
411 return -ENOEXEC;
412 default:
413 printk(KERN_ERR "module %s: unknown relocation: %u\n",
414 me->name, r_type);
415 return -ENOEXEC;
416 }
417 if (rc) {
418 printk(KERN_ERR "module %s: relocation error for symbol %s "
419 "(r_type %i, value 0x%lx)\n",
420 me->name, strtab + symtab[r_sym].st_name,
421 r_type, (unsigned long) val);
422 return rc;
423 }
424 return 0;
425}
426
427static int __apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
428 unsigned int symindex, unsigned int relsec,
429 struct module *me,
430 void *(*write)(void *dest, const void *src, size_t len))
431{
432 Elf_Addr base;
433 Elf_Sym *symtab;
434 Elf_Rela *rela;
435 unsigned long i, n;
436 int rc;
437
438 DEBUGP("Applying relocate section %u to %u\n",
439 relsec, sechdrs[relsec].sh_info);
440 base = sechdrs[sechdrs[relsec].sh_info].sh_addr;
441 symtab = (Elf_Sym *) sechdrs[symindex].sh_addr;
442 rela = (Elf_Rela *) sechdrs[relsec].sh_addr;
443 n = sechdrs[relsec].sh_size / sizeof(Elf_Rela);
444
445 for (i = 0; i < n; i++, rela++) {
446 rc = apply_rela(rela, base, symtab, strtab, me, write);
447 if (rc)
448 return rc;
449 }
450 return 0;
451}
452
453int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
454 unsigned int symindex, unsigned int relsec,
455 struct module *me)
456{
457 bool early = me->state == MODULE_STATE_UNFORMED;
458 void *(*write)(void *, const void *, size_t) = memcpy;
459
460 if (!early)
461 write = s390_kernel_write;
462
463 return __apply_relocate_add(sechdrs, strtab, symindex, relsec, me,
464 write);
465}
466
467#ifdef CONFIG_FUNCTION_TRACER
468static int module_alloc_ftrace_hotpatch_trampolines(struct module *me,
469 const Elf_Shdr *s)
470{
471 char *start, *end;
472 int numpages;
473 size_t size;
474
475 size = FTRACE_HOTPATCH_TRAMPOLINES_SIZE(s->sh_size);
476 numpages = DIV_ROUND_UP(size, PAGE_SIZE);
477 start = execmem_alloc(EXECMEM_FTRACE, numpages * PAGE_SIZE);
478 if (!start)
479 return -ENOMEM;
480 set_memory_rox((unsigned long)start, numpages);
481 end = start + size;
482
483 me->arch.trampolines_start = (struct ftrace_hotpatch_trampoline *)start;
484 me->arch.trampolines_end = (struct ftrace_hotpatch_trampoline *)end;
485 me->arch.next_trampoline = me->arch.trampolines_start;
486
487 return 0;
488}
489#endif /* CONFIG_FUNCTION_TRACER */
490
491int module_finalize(const Elf_Ehdr *hdr,
492 const Elf_Shdr *sechdrs,
493 struct module *me)
494{
495 const Elf_Shdr *s;
496 char *secstrings, *secname;
497 void *aseg;
498#ifdef CONFIG_FUNCTION_TRACER
499 int ret;
500#endif
501
502 if (IS_ENABLED(CONFIG_EXPOLINE) &&
503 !nospec_disable && me->arch.plt_size) {
504 unsigned int *ij;
505
506 ij = me->mem[MOD_TEXT].base + me->arch.plt_offset +
507 me->arch.plt_size - PLT_ENTRY_SIZE;
508 ij[0] = 0xc6000000; /* exrl %r0,.+10 */
509 ij[1] = 0x0005a7f4; /* j . */
510 ij[2] = 0x000007f1; /* br %r1 */
511 }
512
513 secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
514 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
515 aseg = (void *) s->sh_addr;
516 secname = secstrings + s->sh_name;
517
518 if (!strcmp(".altinstructions", secname))
519 /* patch .altinstructions */
520 apply_alternatives(aseg, aseg + s->sh_size);
521
522 if (IS_ENABLED(CONFIG_EXPOLINE) &&
523 (str_has_prefix(secname, ".s390_indirect")))
524 nospec_revert(aseg, aseg + s->sh_size);
525
526 if (IS_ENABLED(CONFIG_EXPOLINE) &&
527 (str_has_prefix(secname, ".s390_return")))
528 nospec_revert(aseg, aseg + s->sh_size);
529
530#ifdef CONFIG_FUNCTION_TRACER
531 if (!strcmp(FTRACE_CALLSITE_SECTION, secname)) {
532 ret = module_alloc_ftrace_hotpatch_trampolines(me, s);
533 if (ret < 0)
534 return ret;
535 }
536#endif /* CONFIG_FUNCTION_TRACER */
537 }
538
539 return 0;
540}
1/*
2 * arch/s390/kernel/module.c - Kernel module help for s390.
3 *
4 * S390 version
5 * Copyright (C) 2002, 2003 IBM Deutschland Entwicklung GmbH,
6 * IBM Corporation
7 * Author(s): Arnd Bergmann (arndb@de.ibm.com)
8 * Martin Schwidefsky (schwidefsky@de.ibm.com)
9 *
10 * based on i386 version
11 * Copyright (C) 2001 Rusty Russell.
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
17 *
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
22 *
23 * You should have received a copy of the GNU General Public License
24 * along with this program; if not, write to the Free Software
25 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
26 */
27#include <linux/module.h>
28#include <linux/elf.h>
29#include <linux/vmalloc.h>
30#include <linux/fs.h>
31#include <linux/string.h>
32#include <linux/kernel.h>
33#include <linux/moduleloader.h>
34#include <linux/bug.h>
35
36#if 0
37#define DEBUGP printk
38#else
39#define DEBUGP(fmt , ...)
40#endif
41
42#ifndef CONFIG_64BIT
43#define PLT_ENTRY_SIZE 12
44#else /* CONFIG_64BIT */
45#define PLT_ENTRY_SIZE 20
46#endif /* CONFIG_64BIT */
47
48/* Free memory returned from module_alloc */
49void module_free(struct module *mod, void *module_region)
50{
51 if (mod) {
52 vfree(mod->arch.syminfo);
53 mod->arch.syminfo = NULL;
54 }
55 vfree(module_region);
56}
57
58static void
59check_rela(Elf_Rela *rela, struct module *me)
60{
61 struct mod_arch_syminfo *info;
62
63 info = me->arch.syminfo + ELF_R_SYM (rela->r_info);
64 switch (ELF_R_TYPE (rela->r_info)) {
65 case R_390_GOT12: /* 12 bit GOT offset. */
66 case R_390_GOT16: /* 16 bit GOT offset. */
67 case R_390_GOT20: /* 20 bit GOT offset. */
68 case R_390_GOT32: /* 32 bit GOT offset. */
69 case R_390_GOT64: /* 64 bit GOT offset. */
70 case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */
71 case R_390_GOTPLT12: /* 12 bit offset to jump slot. */
72 case R_390_GOTPLT16: /* 16 bit offset to jump slot. */
73 case R_390_GOTPLT20: /* 20 bit offset to jump slot. */
74 case R_390_GOTPLT32: /* 32 bit offset to jump slot. */
75 case R_390_GOTPLT64: /* 64 bit offset to jump slot. */
76 case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */
77 if (info->got_offset == -1UL) {
78 info->got_offset = me->arch.got_size;
79 me->arch.got_size += sizeof(void*);
80 }
81 break;
82 case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */
83 case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */
84 case R_390_PLT32: /* 32 bit PC relative PLT address. */
85 case R_390_PLT64: /* 64 bit PC relative PLT address. */
86 case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */
87 case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */
88 case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */
89 if (info->plt_offset == -1UL) {
90 info->plt_offset = me->arch.plt_size;
91 me->arch.plt_size += PLT_ENTRY_SIZE;
92 }
93 break;
94 case R_390_COPY:
95 case R_390_GLOB_DAT:
96 case R_390_JMP_SLOT:
97 case R_390_RELATIVE:
98 /* Only needed if we want to support loading of
99 modules linked with -shared. */
100 break;
101 }
102}
103
104/*
105 * Account for GOT and PLT relocations. We can't add sections for
106 * got and plt but we can increase the core module size.
107 */
108int
109module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
110 char *secstrings, struct module *me)
111{
112 Elf_Shdr *symtab;
113 Elf_Sym *symbols;
114 Elf_Rela *rela;
115 char *strings;
116 int nrela, i, j;
117
118 /* Find symbol table and string table. */
119 symtab = NULL;
120 for (i = 0; i < hdr->e_shnum; i++)
121 switch (sechdrs[i].sh_type) {
122 case SHT_SYMTAB:
123 symtab = sechdrs + i;
124 break;
125 }
126 if (!symtab) {
127 printk(KERN_ERR "module %s: no symbol table\n", me->name);
128 return -ENOEXEC;
129 }
130
131 /* Allocate one syminfo structure per symbol. */
132 me->arch.nsyms = symtab->sh_size / sizeof(Elf_Sym);
133 me->arch.syminfo = vmalloc(me->arch.nsyms *
134 sizeof(struct mod_arch_syminfo));
135 if (!me->arch.syminfo)
136 return -ENOMEM;
137 symbols = (void *) hdr + symtab->sh_offset;
138 strings = (void *) hdr + sechdrs[symtab->sh_link].sh_offset;
139 for (i = 0; i < me->arch.nsyms; i++) {
140 if (symbols[i].st_shndx == SHN_UNDEF &&
141 strcmp(strings + symbols[i].st_name,
142 "_GLOBAL_OFFSET_TABLE_") == 0)
143 /* "Define" it as absolute. */
144 symbols[i].st_shndx = SHN_ABS;
145 me->arch.syminfo[i].got_offset = -1UL;
146 me->arch.syminfo[i].plt_offset = -1UL;
147 me->arch.syminfo[i].got_initialized = 0;
148 me->arch.syminfo[i].plt_initialized = 0;
149 }
150
151 /* Search for got/plt relocations. */
152 me->arch.got_size = me->arch.plt_size = 0;
153 for (i = 0; i < hdr->e_shnum; i++) {
154 if (sechdrs[i].sh_type != SHT_RELA)
155 continue;
156 nrela = sechdrs[i].sh_size / sizeof(Elf_Rela);
157 rela = (void *) hdr + sechdrs[i].sh_offset;
158 for (j = 0; j < nrela; j++)
159 check_rela(rela + j, me);
160 }
161
162 /* Increase core size by size of got & plt and set start
163 offsets for got and plt. */
164 me->core_size = ALIGN(me->core_size, 4);
165 me->arch.got_offset = me->core_size;
166 me->core_size += me->arch.got_size;
167 me->arch.plt_offset = me->core_size;
168 me->core_size += me->arch.plt_size;
169 return 0;
170}
171
172static int
173apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
174 struct module *me)
175{
176 struct mod_arch_syminfo *info;
177 Elf_Addr loc, val;
178 int r_type, r_sym;
179
180 /* This is where to make the change */
181 loc = base + rela->r_offset;
182 /* This is the symbol it is referring to. Note that all
183 undefined symbols have been resolved. */
184 r_sym = ELF_R_SYM(rela->r_info);
185 r_type = ELF_R_TYPE(rela->r_info);
186 info = me->arch.syminfo + r_sym;
187 val = symtab[r_sym].st_value;
188
189 switch (r_type) {
190 case R_390_8: /* Direct 8 bit. */
191 case R_390_12: /* Direct 12 bit. */
192 case R_390_16: /* Direct 16 bit. */
193 case R_390_20: /* Direct 20 bit. */
194 case R_390_32: /* Direct 32 bit. */
195 case R_390_64: /* Direct 64 bit. */
196 val += rela->r_addend;
197 if (r_type == R_390_8)
198 *(unsigned char *) loc = val;
199 else if (r_type == R_390_12)
200 *(unsigned short *) loc = (val & 0xfff) |
201 (*(unsigned short *) loc & 0xf000);
202 else if (r_type == R_390_16)
203 *(unsigned short *) loc = val;
204 else if (r_type == R_390_20)
205 *(unsigned int *) loc =
206 (*(unsigned int *) loc & 0xf00000ff) |
207 (val & 0xfff) << 16 | (val & 0xff000) >> 4;
208 else if (r_type == R_390_32)
209 *(unsigned int *) loc = val;
210 else if (r_type == R_390_64)
211 *(unsigned long *) loc = val;
212 break;
213 case R_390_PC16: /* PC relative 16 bit. */
214 case R_390_PC16DBL: /* PC relative 16 bit shifted by 1. */
215 case R_390_PC32DBL: /* PC relative 32 bit shifted by 1. */
216 case R_390_PC32: /* PC relative 32 bit. */
217 case R_390_PC64: /* PC relative 64 bit. */
218 val += rela->r_addend - loc;
219 if (r_type == R_390_PC16)
220 *(unsigned short *) loc = val;
221 else if (r_type == R_390_PC16DBL)
222 *(unsigned short *) loc = val >> 1;
223 else if (r_type == R_390_PC32DBL)
224 *(unsigned int *) loc = val >> 1;
225 else if (r_type == R_390_PC32)
226 *(unsigned int *) loc = val;
227 else if (r_type == R_390_PC64)
228 *(unsigned long *) loc = val;
229 break;
230 case R_390_GOT12: /* 12 bit GOT offset. */
231 case R_390_GOT16: /* 16 bit GOT offset. */
232 case R_390_GOT20: /* 20 bit GOT offset. */
233 case R_390_GOT32: /* 32 bit GOT offset. */
234 case R_390_GOT64: /* 64 bit GOT offset. */
235 case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */
236 case R_390_GOTPLT12: /* 12 bit offset to jump slot. */
237 case R_390_GOTPLT20: /* 20 bit offset to jump slot. */
238 case R_390_GOTPLT16: /* 16 bit offset to jump slot. */
239 case R_390_GOTPLT32: /* 32 bit offset to jump slot. */
240 case R_390_GOTPLT64: /* 64 bit offset to jump slot. */
241 case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */
242 if (info->got_initialized == 0) {
243 Elf_Addr *gotent;
244
245 gotent = me->module_core + me->arch.got_offset +
246 info->got_offset;
247 *gotent = val;
248 info->got_initialized = 1;
249 }
250 val = info->got_offset + rela->r_addend;
251 if (r_type == R_390_GOT12 ||
252 r_type == R_390_GOTPLT12)
253 *(unsigned short *) loc = (val & 0xfff) |
254 (*(unsigned short *) loc & 0xf000);
255 else if (r_type == R_390_GOT16 ||
256 r_type == R_390_GOTPLT16)
257 *(unsigned short *) loc = val;
258 else if (r_type == R_390_GOT20 ||
259 r_type == R_390_GOTPLT20)
260 *(unsigned int *) loc =
261 (*(unsigned int *) loc & 0xf00000ff) |
262 (val & 0xfff) << 16 | (val & 0xff000) >> 4;
263 else if (r_type == R_390_GOT32 ||
264 r_type == R_390_GOTPLT32)
265 *(unsigned int *) loc = val;
266 else if (r_type == R_390_GOTENT ||
267 r_type == R_390_GOTPLTENT)
268 *(unsigned int *) loc =
269 (val + (Elf_Addr) me->module_core - loc) >> 1;
270 else if (r_type == R_390_GOT64 ||
271 r_type == R_390_GOTPLT64)
272 *(unsigned long *) loc = val;
273 break;
274 case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */
275 case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */
276 case R_390_PLT32: /* 32 bit PC relative PLT address. */
277 case R_390_PLT64: /* 64 bit PC relative PLT address. */
278 case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */
279 case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */
280 case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */
281 if (info->plt_initialized == 0) {
282 unsigned int *ip;
283 ip = me->module_core + me->arch.plt_offset +
284 info->plt_offset;
285#ifndef CONFIG_64BIT
286 ip[0] = 0x0d105810; /* basr 1,0; l 1,6(1); br 1 */
287 ip[1] = 0x100607f1;
288 ip[2] = val;
289#else /* CONFIG_64BIT */
290 ip[0] = 0x0d10e310; /* basr 1,0; lg 1,10(1); br 1 */
291 ip[1] = 0x100a0004;
292 ip[2] = 0x07f10000;
293 ip[3] = (unsigned int) (val >> 32);
294 ip[4] = (unsigned int) val;
295#endif /* CONFIG_64BIT */
296 info->plt_initialized = 1;
297 }
298 if (r_type == R_390_PLTOFF16 ||
299 r_type == R_390_PLTOFF32 ||
300 r_type == R_390_PLTOFF64)
301 val = me->arch.plt_offset - me->arch.got_offset +
302 info->plt_offset + rela->r_addend;
303 else {
304 if (!((r_type == R_390_PLT16DBL &&
305 val - loc + 0xffffUL < 0x1ffffeUL) ||
306 (r_type == R_390_PLT32DBL &&
307 val - loc + 0xffffffffULL < 0x1fffffffeULL)))
308 val = (Elf_Addr) me->module_core +
309 me->arch.plt_offset +
310 info->plt_offset;
311 val += rela->r_addend - loc;
312 }
313 if (r_type == R_390_PLT16DBL)
314 *(unsigned short *) loc = val >> 1;
315 else if (r_type == R_390_PLTOFF16)
316 *(unsigned short *) loc = val;
317 else if (r_type == R_390_PLT32DBL)
318 *(unsigned int *) loc = val >> 1;
319 else if (r_type == R_390_PLT32 ||
320 r_type == R_390_PLTOFF32)
321 *(unsigned int *) loc = val;
322 else if (r_type == R_390_PLT64 ||
323 r_type == R_390_PLTOFF64)
324 *(unsigned long *) loc = val;
325 break;
326 case R_390_GOTOFF16: /* 16 bit offset to GOT. */
327 case R_390_GOTOFF32: /* 32 bit offset to GOT. */
328 case R_390_GOTOFF64: /* 64 bit offset to GOT. */
329 val = val + rela->r_addend -
330 ((Elf_Addr) me->module_core + me->arch.got_offset);
331 if (r_type == R_390_GOTOFF16)
332 *(unsigned short *) loc = val;
333 else if (r_type == R_390_GOTOFF32)
334 *(unsigned int *) loc = val;
335 else if (r_type == R_390_GOTOFF64)
336 *(unsigned long *) loc = val;
337 break;
338 case R_390_GOTPC: /* 32 bit PC relative offset to GOT. */
339 case R_390_GOTPCDBL: /* 32 bit PC rel. off. to GOT shifted by 1. */
340 val = (Elf_Addr) me->module_core + me->arch.got_offset +
341 rela->r_addend - loc;
342 if (r_type == R_390_GOTPC)
343 *(unsigned int *) loc = val;
344 else if (r_type == R_390_GOTPCDBL)
345 *(unsigned int *) loc = val >> 1;
346 break;
347 case R_390_COPY:
348 case R_390_GLOB_DAT: /* Create GOT entry. */
349 case R_390_JMP_SLOT: /* Create PLT entry. */
350 case R_390_RELATIVE: /* Adjust by program base. */
351 /* Only needed if we want to support loading of
352 modules linked with -shared. */
353 break;
354 default:
355 printk(KERN_ERR "module %s: Unknown relocation: %u\n",
356 me->name, r_type);
357 return -ENOEXEC;
358 }
359 return 0;
360}
361
362int
363apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
364 unsigned int symindex, unsigned int relsec,
365 struct module *me)
366{
367 Elf_Addr base;
368 Elf_Sym *symtab;
369 Elf_Rela *rela;
370 unsigned long i, n;
371 int rc;
372
373 DEBUGP("Applying relocate section %u to %u\n",
374 relsec, sechdrs[relsec].sh_info);
375 base = sechdrs[sechdrs[relsec].sh_info].sh_addr;
376 symtab = (Elf_Sym *) sechdrs[symindex].sh_addr;
377 rela = (Elf_Rela *) sechdrs[relsec].sh_addr;
378 n = sechdrs[relsec].sh_size / sizeof(Elf_Rela);
379
380 for (i = 0; i < n; i++, rela++) {
381 rc = apply_rela(rela, base, symtab, me);
382 if (rc)
383 return rc;
384 }
385 return 0;
386}
387
388int module_finalize(const Elf_Ehdr *hdr,
389 const Elf_Shdr *sechdrs,
390 struct module *me)
391{
392 vfree(me->arch.syminfo);
393 me->arch.syminfo = NULL;
394 return 0;
395}