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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// 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/string.h>
18#include <linux/kernel.h>
19#include <linux/moduleloader.h>
20#include <linux/bug.h>
21#include <asm/alternative.h>
22#include <asm/nospec-branch.h>
23#include <asm/facility.h>
24
25#if 0
26#define DEBUGP printk
27#else
28#define DEBUGP(fmt , ...)
29#endif
30
31#define PLT_ENTRY_SIZE 20
32
33void *module_alloc(unsigned long size)
34{
35 if (PAGE_ALIGN(size) > MODULES_LEN)
36 return NULL;
37 return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
38 GFP_KERNEL, PAGE_KERNEL_EXEC,
39 0, NUMA_NO_NODE,
40 __builtin_return_address(0));
41}
42
43void module_arch_freeing_init(struct module *mod)
44{
45 if (is_livepatch_module(mod) &&
46 mod->state == MODULE_STATE_LIVE)
47 return;
48
49 vfree(mod->arch.syminfo);
50 mod->arch.syminfo = NULL;
51}
52
53static void check_rela(Elf_Rela *rela, struct module *me)
54{
55 struct mod_arch_syminfo *info;
56
57 info = me->arch.syminfo + ELF_R_SYM (rela->r_info);
58 switch (ELF_R_TYPE (rela->r_info)) {
59 case R_390_GOT12: /* 12 bit GOT offset. */
60 case R_390_GOT16: /* 16 bit GOT offset. */
61 case R_390_GOT20: /* 20 bit GOT offset. */
62 case R_390_GOT32: /* 32 bit GOT offset. */
63 case R_390_GOT64: /* 64 bit GOT offset. */
64 case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */
65 case R_390_GOTPLT12: /* 12 bit offset to jump slot. */
66 case R_390_GOTPLT16: /* 16 bit offset to jump slot. */
67 case R_390_GOTPLT20: /* 20 bit offset to jump slot. */
68 case R_390_GOTPLT32: /* 32 bit offset to jump slot. */
69 case R_390_GOTPLT64: /* 64 bit offset to jump slot. */
70 case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */
71 if (info->got_offset == -1UL) {
72 info->got_offset = me->arch.got_size;
73 me->arch.got_size += sizeof(void*);
74 }
75 break;
76 case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */
77 case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */
78 case R_390_PLT32: /* 32 bit PC relative PLT address. */
79 case R_390_PLT64: /* 64 bit PC relative PLT address. */
80 case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */
81 case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */
82 case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */
83 if (info->plt_offset == -1UL) {
84 info->plt_offset = me->arch.plt_size;
85 me->arch.plt_size += PLT_ENTRY_SIZE;
86 }
87 break;
88 case R_390_COPY:
89 case R_390_GLOB_DAT:
90 case R_390_JMP_SLOT:
91 case R_390_RELATIVE:
92 /* Only needed if we want to support loading of
93 modules linked with -shared. */
94 break;
95 }
96}
97
98/*
99 * Account for GOT and PLT relocations. We can't add sections for
100 * got and plt but we can increase the core module size.
101 */
102int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
103 char *secstrings, struct module *me)
104{
105 Elf_Shdr *symtab;
106 Elf_Sym *symbols;
107 Elf_Rela *rela;
108 char *strings;
109 int nrela, i, j;
110
111 /* Find symbol table and string table. */
112 symtab = NULL;
113 for (i = 0; i < hdr->e_shnum; i++)
114 switch (sechdrs[i].sh_type) {
115 case SHT_SYMTAB:
116 symtab = sechdrs + i;
117 break;
118 }
119 if (!symtab) {
120 printk(KERN_ERR "module %s: no symbol table\n", me->name);
121 return -ENOEXEC;
122 }
123
124 /* Allocate one syminfo structure per symbol. */
125 me->arch.nsyms = symtab->sh_size / sizeof(Elf_Sym);
126 me->arch.syminfo = vmalloc(me->arch.nsyms *
127 sizeof(struct mod_arch_syminfo));
128 if (!me->arch.syminfo)
129 return -ENOMEM;
130 symbols = (void *) hdr + symtab->sh_offset;
131 strings = (void *) hdr + sechdrs[symtab->sh_link].sh_offset;
132 for (i = 0; i < me->arch.nsyms; i++) {
133 if (symbols[i].st_shndx == SHN_UNDEF &&
134 strcmp(strings + symbols[i].st_name,
135 "_GLOBAL_OFFSET_TABLE_") == 0)
136 /* "Define" it as absolute. */
137 symbols[i].st_shndx = SHN_ABS;
138 me->arch.syminfo[i].got_offset = -1UL;
139 me->arch.syminfo[i].plt_offset = -1UL;
140 me->arch.syminfo[i].got_initialized = 0;
141 me->arch.syminfo[i].plt_initialized = 0;
142 }
143
144 /* Search for got/plt relocations. */
145 me->arch.got_size = me->arch.plt_size = 0;
146 for (i = 0; i < hdr->e_shnum; i++) {
147 if (sechdrs[i].sh_type != SHT_RELA)
148 continue;
149 nrela = sechdrs[i].sh_size / sizeof(Elf_Rela);
150 rela = (void *) hdr + sechdrs[i].sh_offset;
151 for (j = 0; j < nrela; j++)
152 check_rela(rela + j, me);
153 }
154
155 /* Increase core size by size of got & plt and set start
156 offsets for got and plt. */
157 me->core_layout.size = ALIGN(me->core_layout.size, 4);
158 me->arch.got_offset = me->core_layout.size;
159 me->core_layout.size += me->arch.got_size;
160 me->arch.plt_offset = me->core_layout.size;
161 if (me->arch.plt_size) {
162 if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_disable)
163 me->arch.plt_size += PLT_ENTRY_SIZE;
164 me->core_layout.size += me->arch.plt_size;
165 }
166 return 0;
167}
168
169static int apply_rela_bits(Elf_Addr loc, Elf_Addr val,
170 int sign, int bits, int shift)
171{
172 unsigned long umax;
173 long min, max;
174
175 if (val & ((1UL << shift) - 1))
176 return -ENOEXEC;
177 if (sign) {
178 val = (Elf_Addr)(((long) val) >> shift);
179 min = -(1L << (bits - 1));
180 max = (1L << (bits - 1)) - 1;
181 if ((long) val < min || (long) val > max)
182 return -ENOEXEC;
183 } else {
184 val >>= shift;
185 umax = ((1UL << (bits - 1)) << 1) - 1;
186 if ((unsigned long) val > umax)
187 return -ENOEXEC;
188 }
189
190 if (bits == 8)
191 *(unsigned char *) loc = val;
192 else if (bits == 12)
193 *(unsigned short *) loc = (val & 0xfff) |
194 (*(unsigned short *) loc & 0xf000);
195 else if (bits == 16)
196 *(unsigned short *) loc = val;
197 else if (bits == 20)
198 *(unsigned int *) loc = (val & 0xfff) << 16 |
199 (val & 0xff000) >> 4 |
200 (*(unsigned int *) loc & 0xf00000ff);
201 else if (bits == 32)
202 *(unsigned int *) loc = val;
203 else if (bits == 64)
204 *(unsigned long *) loc = val;
205 return 0;
206}
207
208static int apply_rela(Elf_Rela *rela, Elf_Addr base, Elf_Sym *symtab,
209 const char *strtab, struct module *me)
210{
211 struct mod_arch_syminfo *info;
212 Elf_Addr loc, val;
213 int r_type, r_sym;
214 int rc = -ENOEXEC;
215
216 /* This is where to make the change */
217 loc = base + rela->r_offset;
218 /* This is the symbol it is referring to. Note that all
219 undefined symbols have been resolved. */
220 r_sym = ELF_R_SYM(rela->r_info);
221 r_type = ELF_R_TYPE(rela->r_info);
222 info = me->arch.syminfo + r_sym;
223 val = symtab[r_sym].st_value;
224
225 switch (r_type) {
226 case R_390_NONE: /* No relocation. */
227 rc = 0;
228 break;
229 case R_390_8: /* Direct 8 bit. */
230 case R_390_12: /* Direct 12 bit. */
231 case R_390_16: /* Direct 16 bit. */
232 case R_390_20: /* Direct 20 bit. */
233 case R_390_32: /* Direct 32 bit. */
234 case R_390_64: /* Direct 64 bit. */
235 val += rela->r_addend;
236 if (r_type == R_390_8)
237 rc = apply_rela_bits(loc, val, 0, 8, 0);
238 else if (r_type == R_390_12)
239 rc = apply_rela_bits(loc, val, 0, 12, 0);
240 else if (r_type == R_390_16)
241 rc = apply_rela_bits(loc, val, 0, 16, 0);
242 else if (r_type == R_390_20)
243 rc = apply_rela_bits(loc, val, 1, 20, 0);
244 else if (r_type == R_390_32)
245 rc = apply_rela_bits(loc, val, 0, 32, 0);
246 else if (r_type == R_390_64)
247 rc = apply_rela_bits(loc, val, 0, 64, 0);
248 break;
249 case R_390_PC16: /* PC relative 16 bit. */
250 case R_390_PC16DBL: /* PC relative 16 bit shifted by 1. */
251 case R_390_PC32DBL: /* PC relative 32 bit shifted by 1. */
252 case R_390_PC32: /* PC relative 32 bit. */
253 case R_390_PC64: /* PC relative 64 bit. */
254 val += rela->r_addend - loc;
255 if (r_type == R_390_PC16)
256 rc = apply_rela_bits(loc, val, 1, 16, 0);
257 else if (r_type == R_390_PC16DBL)
258 rc = apply_rela_bits(loc, val, 1, 16, 1);
259 else if (r_type == R_390_PC32DBL)
260 rc = apply_rela_bits(loc, val, 1, 32, 1);
261 else if (r_type == R_390_PC32)
262 rc = apply_rela_bits(loc, val, 1, 32, 0);
263 else if (r_type == R_390_PC64)
264 rc = apply_rela_bits(loc, val, 1, 64, 0);
265 break;
266 case R_390_GOT12: /* 12 bit GOT offset. */
267 case R_390_GOT16: /* 16 bit GOT offset. */
268 case R_390_GOT20: /* 20 bit GOT offset. */
269 case R_390_GOT32: /* 32 bit GOT offset. */
270 case R_390_GOT64: /* 64 bit GOT offset. */
271 case R_390_GOTENT: /* 32 bit PC rel. to GOT entry shifted by 1. */
272 case R_390_GOTPLT12: /* 12 bit offset to jump slot. */
273 case R_390_GOTPLT20: /* 20 bit offset to jump slot. */
274 case R_390_GOTPLT16: /* 16 bit offset to jump slot. */
275 case R_390_GOTPLT32: /* 32 bit offset to jump slot. */
276 case R_390_GOTPLT64: /* 64 bit offset to jump slot. */
277 case R_390_GOTPLTENT: /* 32 bit rel. offset to jump slot >> 1. */
278 if (info->got_initialized == 0) {
279 Elf_Addr *gotent;
280
281 gotent = me->core_layout.base + me->arch.got_offset +
282 info->got_offset;
283 *gotent = val;
284 info->got_initialized = 1;
285 }
286 val = info->got_offset + rela->r_addend;
287 if (r_type == R_390_GOT12 ||
288 r_type == R_390_GOTPLT12)
289 rc = apply_rela_bits(loc, val, 0, 12, 0);
290 else if (r_type == R_390_GOT16 ||
291 r_type == R_390_GOTPLT16)
292 rc = apply_rela_bits(loc, val, 0, 16, 0);
293 else if (r_type == R_390_GOT20 ||
294 r_type == R_390_GOTPLT20)
295 rc = apply_rela_bits(loc, val, 1, 20, 0);
296 else if (r_type == R_390_GOT32 ||
297 r_type == R_390_GOTPLT32)
298 rc = apply_rela_bits(loc, val, 0, 32, 0);
299 else if (r_type == R_390_GOT64 ||
300 r_type == R_390_GOTPLT64)
301 rc = apply_rela_bits(loc, val, 0, 64, 0);
302 else if (r_type == R_390_GOTENT ||
303 r_type == R_390_GOTPLTENT) {
304 val += (Elf_Addr) me->core_layout.base - loc;
305 rc = apply_rela_bits(loc, val, 1, 32, 1);
306 }
307 break;
308 case R_390_PLT16DBL: /* 16 bit PC rel. PLT shifted by 1. */
309 case R_390_PLT32DBL: /* 32 bit PC rel. PLT shifted by 1. */
310 case R_390_PLT32: /* 32 bit PC relative PLT address. */
311 case R_390_PLT64: /* 64 bit PC relative PLT address. */
312 case R_390_PLTOFF16: /* 16 bit offset from GOT to PLT. */
313 case R_390_PLTOFF32: /* 32 bit offset from GOT to PLT. */
314 case R_390_PLTOFF64: /* 16 bit offset from GOT to PLT. */
315 if (info->plt_initialized == 0) {
316 unsigned int *ip;
317 ip = me->core_layout.base + me->arch.plt_offset +
318 info->plt_offset;
319 ip[0] = 0x0d10e310; /* basr 1,0 */
320 ip[1] = 0x100a0004; /* lg 1,10(1) */
321 if (IS_ENABLED(CONFIG_EXPOLINE) && !nospec_disable) {
322 unsigned int *ij;
323 ij = me->core_layout.base +
324 me->arch.plt_offset +
325 me->arch.plt_size - PLT_ENTRY_SIZE;
326 ip[2] = 0xa7f40000 + /* j __jump_r1 */
327 (unsigned int)(u16)
328 (((unsigned long) ij - 8 -
329 (unsigned long) ip) / 2);
330 } else {
331 ip[2] = 0x07f10000; /* br %r1 */
332 }
333 ip[3] = (unsigned int) (val >> 32);
334 ip[4] = (unsigned int) val;
335 info->plt_initialized = 1;
336 }
337 if (r_type == R_390_PLTOFF16 ||
338 r_type == R_390_PLTOFF32 ||
339 r_type == R_390_PLTOFF64)
340 val = me->arch.plt_offset - me->arch.got_offset +
341 info->plt_offset + rela->r_addend;
342 else {
343 if (!((r_type == R_390_PLT16DBL &&
344 val - loc + 0xffffUL < 0x1ffffeUL) ||
345 (r_type == R_390_PLT32DBL &&
346 val - loc + 0xffffffffULL < 0x1fffffffeULL)))
347 val = (Elf_Addr) me->core_layout.base +
348 me->arch.plt_offset +
349 info->plt_offset;
350 val += rela->r_addend - loc;
351 }
352 if (r_type == R_390_PLT16DBL)
353 rc = apply_rela_bits(loc, val, 1, 16, 1);
354 else if (r_type == R_390_PLTOFF16)
355 rc = apply_rela_bits(loc, val, 0, 16, 0);
356 else if (r_type == R_390_PLT32DBL)
357 rc = apply_rela_bits(loc, val, 1, 32, 1);
358 else if (r_type == R_390_PLT32 ||
359 r_type == R_390_PLTOFF32)
360 rc = apply_rela_bits(loc, val, 0, 32, 0);
361 else if (r_type == R_390_PLT64 ||
362 r_type == R_390_PLTOFF64)
363 rc = apply_rela_bits(loc, val, 0, 64, 0);
364 break;
365 case R_390_GOTOFF16: /* 16 bit offset to GOT. */
366 case R_390_GOTOFF32: /* 32 bit offset to GOT. */
367 case R_390_GOTOFF64: /* 64 bit offset to GOT. */
368 val = val + rela->r_addend -
369 ((Elf_Addr) me->core_layout.base + me->arch.got_offset);
370 if (r_type == R_390_GOTOFF16)
371 rc = apply_rela_bits(loc, val, 0, 16, 0);
372 else if (r_type == R_390_GOTOFF32)
373 rc = apply_rela_bits(loc, val, 0, 32, 0);
374 else if (r_type == R_390_GOTOFF64)
375 rc = apply_rela_bits(loc, val, 0, 64, 0);
376 break;
377 case R_390_GOTPC: /* 32 bit PC relative offset to GOT. */
378 case R_390_GOTPCDBL: /* 32 bit PC rel. off. to GOT shifted by 1. */
379 val = (Elf_Addr) me->core_layout.base + me->arch.got_offset +
380 rela->r_addend - loc;
381 if (r_type == R_390_GOTPC)
382 rc = apply_rela_bits(loc, val, 1, 32, 0);
383 else if (r_type == R_390_GOTPCDBL)
384 rc = apply_rela_bits(loc, val, 1, 32, 1);
385 break;
386 case R_390_COPY:
387 case R_390_GLOB_DAT: /* Create GOT entry. */
388 case R_390_JMP_SLOT: /* Create PLT entry. */
389 case R_390_RELATIVE: /* Adjust by program base. */
390 /* Only needed if we want to support loading of
391 modules linked with -shared. */
392 return -ENOEXEC;
393 default:
394 printk(KERN_ERR "module %s: unknown relocation: %u\n",
395 me->name, r_type);
396 return -ENOEXEC;
397 }
398 if (rc) {
399 printk(KERN_ERR "module %s: relocation error for symbol %s "
400 "(r_type %i, value 0x%lx)\n",
401 me->name, strtab + symtab[r_sym].st_name,
402 r_type, (unsigned long) val);
403 return rc;
404 }
405 return 0;
406}
407
408int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
409 unsigned int symindex, unsigned int relsec,
410 struct module *me)
411{
412 Elf_Addr base;
413 Elf_Sym *symtab;
414 Elf_Rela *rela;
415 unsigned long i, n;
416 int rc;
417
418 DEBUGP("Applying relocate section %u to %u\n",
419 relsec, sechdrs[relsec].sh_info);
420 base = sechdrs[sechdrs[relsec].sh_info].sh_addr;
421 symtab = (Elf_Sym *) sechdrs[symindex].sh_addr;
422 rela = (Elf_Rela *) sechdrs[relsec].sh_addr;
423 n = sechdrs[relsec].sh_size / sizeof(Elf_Rela);
424
425 for (i = 0; i < n; i++, rela++) {
426 rc = apply_rela(rela, base, symtab, strtab, me);
427 if (rc)
428 return rc;
429 }
430 return 0;
431}
432
433int module_finalize(const Elf_Ehdr *hdr,
434 const Elf_Shdr *sechdrs,
435 struct module *me)
436{
437 const Elf_Shdr *s;
438 char *secstrings, *secname;
439 void *aseg;
440
441 if (IS_ENABLED(CONFIG_EXPOLINE) &&
442 !nospec_disable && me->arch.plt_size) {
443 unsigned int *ij;
444
445 ij = me->core_layout.base + me->arch.plt_offset +
446 me->arch.plt_size - PLT_ENTRY_SIZE;
447 if (test_facility(35)) {
448 ij[0] = 0xc6000000; /* exrl %r0,.+10 */
449 ij[1] = 0x0005a7f4; /* j . */
450 ij[2] = 0x000007f1; /* br %r1 */
451 } else {
452 ij[0] = 0x44000000 | (unsigned int)
453 offsetof(struct lowcore, br_r1_trampoline);
454 ij[1] = 0xa7f40000; /* j . */
455 }
456 }
457
458 secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
459 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
460 aseg = (void *) s->sh_addr;
461 secname = secstrings + s->sh_name;
462
463 if (!strcmp(".altinstructions", secname))
464 /* patch .altinstructions */
465 apply_alternatives(aseg, aseg + s->sh_size);
466
467 if (IS_ENABLED(CONFIG_EXPOLINE) &&
468 (!strncmp(".s390_indirect", secname, 14)))
469 nospec_revert(aseg, aseg + s->sh_size);
470
471 if (IS_ENABLED(CONFIG_EXPOLINE) &&
472 (!strncmp(".s390_return", secname, 12)))
473 nospec_revert(aseg, aseg + s->sh_size);
474 }
475
476 jump_label_apply_nops(me);
477 return 0;
478}