?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / arch / s390 / kernel / module.c
blob1fc6d1ff92d3ec2d564d151b4c8355d08a1714c4
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
33 void *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
43 void 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
53 static 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 */
102 int 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_call_disable)
163 me->arch.plt_size += PLT_ENTRY_SIZE;
164 me->core_layout.size += me->arch.plt_size;
165 }
166 return 0;
167 }
168
169 static 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
208 static 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) &&
322 !nospec_call_disable) {
323 unsigned int *ij;
324 ij = me->core_layout.base +
325 me->arch.plt_offset +
326 me->arch.plt_size - PLT_ENTRY_SIZE;
327 ip[2] = 0xa7f40000 + /* j __jump_r1 */
328 (unsigned int)(u16)
329 (((unsigned long) ij - 8 -
330 (unsigned long) ip) / 2);
331 } else {
332 ip[2] = 0x07f10000; /* br %r1 */
333 }
334 ip[3] = (unsigned int) (val >> 32);
335 ip[4] = (unsigned int) val;
336 info->plt_initialized = 1;
337 }
338 if (r_type == R_390_PLTOFF16 ||
339 r_type == R_390_PLTOFF32 ||
340 r_type == R_390_PLTOFF64)
341 val = me->arch.plt_offset - me->arch.got_offset +
342 info->plt_offset + rela->r_addend;
343 else {
344 if (!((r_type == R_390_PLT16DBL &&
345 val - loc + 0xffffUL < 0x1ffffeUL) ||
346 (r_type == R_390_PLT32DBL &&
347 val - loc + 0xffffffffULL < 0x1fffffffeULL)))
348 val = (Elf_Addr) me->core_layout.base +
349 me->arch.plt_offset +
350 info->plt_offset;
351 val += rela->r_addend - loc;
352 }
353 if (r_type == R_390_PLT16DBL)
354 rc = apply_rela_bits(loc, val, 1, 16, 1);
355 else if (r_type == R_390_PLTOFF16)
356 rc = apply_rela_bits(loc, val, 0, 16, 0);
357 else if (r_type == R_390_PLT32DBL)
358 rc = apply_rela_bits(loc, val, 1, 32, 1);
359 else if (r_type == R_390_PLT32 ||
360 r_type == R_390_PLTOFF32)
361 rc = apply_rela_bits(loc, val, 0, 32, 0);
362 else if (r_type == R_390_PLT64 ||
363 r_type == R_390_PLTOFF64)
364 rc = apply_rela_bits(loc, val, 0, 64, 0);
365 break;
366 case R_390_GOTOFF16: /* 16 bit offset to GOT. */
367 case R_390_GOTOFF32: /* 32 bit offset to GOT. */
368 case R_390_GOTOFF64: /* 64 bit offset to GOT. */
369 val = val + rela->r_addend -
370 ((Elf_Addr) me->core_layout.base + me->arch.got_offset);
371 if (r_type == R_390_GOTOFF16)
372 rc = apply_rela_bits(loc, val, 0, 16, 0);
373 else if (r_type == R_390_GOTOFF32)
374 rc = apply_rela_bits(loc, val, 0, 32, 0);
375 else if (r_type == R_390_GOTOFF64)
376 rc = apply_rela_bits(loc, val, 0, 64, 0);
377 break;
378 case R_390_GOTPC: /* 32 bit PC relative offset to GOT. */
379 case R_390_GOTPCDBL: /* 32 bit PC rel. off. to GOT shifted by 1. */
380 val = (Elf_Addr) me->core_layout.base + me->arch.got_offset +
381 rela->r_addend - loc;
382 if (r_type == R_390_GOTPC)
383 rc = apply_rela_bits(loc, val, 1, 32, 0);
384 else if (r_type == R_390_GOTPCDBL)
385 rc = apply_rela_bits(loc, val, 1, 32, 1);
386 break;
387 case R_390_COPY:
388 case R_390_GLOB_DAT: /* Create GOT entry. */
389 case R_390_JMP_SLOT: /* Create PLT entry. */
390 case R_390_RELATIVE: /* Adjust by program base. */
391 /* Only needed if we want to support loading of
392 modules linked with -shared. */
393 return -ENOEXEC;
394 default:
395 printk(KERN_ERR "module %s: unknown relocation: %u\n",
396 me->name, r_type);
397 return -ENOEXEC;
398 }
399 if (rc) {
400 printk(KERN_ERR "module %s: relocation error for symbol %s "
401 "(r_type %i, value 0x%lx)\n",
402 me->name, strtab + symtab[r_sym].st_name,
403 r_type, (unsigned long) val);
404 return rc;
405 }
406 return 0;
407 }
408
409 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
410 unsigned int symindex, unsigned int relsec,
411 struct module *me)
412 {
413 Elf_Addr base;
414 Elf_Sym *symtab;
415 Elf_Rela *rela;
416 unsigned long i, n;
417 int rc;
418
419 DEBUGP("Applying relocate section %u to %u\n",
420 relsec, sechdrs[relsec].sh_info);
421 base = sechdrs[sechdrs[relsec].sh_info].sh_addr;
422 symtab = (Elf_Sym *) sechdrs[symindex].sh_addr;
423 rela = (Elf_Rela *) sechdrs[relsec].sh_addr;
424 n = sechdrs[relsec].sh_size / sizeof(Elf_Rela);
425
426 for (i = 0; i < n; i++, rela++) {
427 rc = apply_rela(rela, base, symtab, strtab, me);
428 if (rc)
429 return rc;
430 }
431 return 0;
432 }
433
434 int module_finalize(const Elf_Ehdr *hdr,
435 const Elf_Shdr *sechdrs,
436 struct module *me)
437 {
438 const Elf_Shdr *s;
439 char *secstrings, *secname;
440 void *aseg;
441
442 if (IS_ENABLED(CONFIG_EXPOLINE) &&
443 !nospec_call_disable && me->arch.plt_size) {
444 unsigned int *ij;
445
446 ij = me->core_layout.base + me->arch.plt_offset +
447 me->arch.plt_size - PLT_ENTRY_SIZE;
448 if (test_facility(35)) {
449 ij[0] = 0xc6000000; /* exrl %r0,.+10 */
450 ij[1] = 0x0005a7f4; /* j . */
451 ij[2] = 0x000007f1; /* br %r1 */
452 } else {
453 ij[0] = 0x44000000 | (unsigned int)
454 offsetof(struct lowcore, br_r1_trampoline);
455 ij[1] = 0xa7f40000; /* j . */
456 }
457 }
458
459 secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
460 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
461 aseg = (void *) s->sh_addr;
462 secname = secstrings + s->sh_name;
463
464 if (!strcmp(".altinstructions", secname))
465 /* patch .altinstructions */
466 apply_alternatives(aseg, aseg + s->sh_size);
467
468 if (IS_ENABLED(CONFIG_EXPOLINE) &&
469 (!strcmp(".nospec_call_table", secname)))
470 nospec_call_revert(aseg, aseg + s->sh_size);
471
472 if (IS_ENABLED(CONFIG_EXPOLINE) &&
473 (!strcmp(".nospec_return_table", secname)))
474 nospec_return_revert(aseg, aseg + s->sh_size);
475 }
476
477 jump_label_apply_nops(me);
478 return 0;
479 }
CRIS linux kernel tree