1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 *
4 * Copyright (C) 2017 Zihao Yu
5 */
6
7 #include <linux/elf.h>
8 #include <linux/err.h>
9 #include <linux/errno.h>
10 #include <linux/moduleloader.h>
11 #include <linux/vmalloc.h>
12 #include <linux/sizes.h>
13 #include <linux/pgtable.h>
14 #include <asm/alternative.h>
15 #include <asm/sections.h>
16
17 /*
18 * The auipc+jalr instruction pair can reach any PC-relative offset
19 * in the range [-2^31 - 2^11, 2^31 - 2^11)
20 */
riscv_insn_valid_32bit_offset(ptrdiff_t val)21 static bool riscv_insn_valid_32bit_offset(ptrdiff_t val)
22 {
23 #ifdef CONFIG_32BIT
24 return true;
25 #else
26 return (-(1L << 31) - (1L << 11)) <= val && val < ((1L << 31) - (1L << 11));
27 #endif
28 }
29
apply_r_riscv_32_rela(struct module * me,u32 * location,Elf_Addr v)30 static int apply_r_riscv_32_rela(struct module *me, u32 *location, Elf_Addr v)
31 {
32 if (v != (u32)v) {
33 pr_err("%s: value %016llx out of range for 32-bit field\n",
34 me->name, (long long)v);
35 return -EINVAL;
36 }
37 *location = v;
38 return 0;
39 }
40
apply_r_riscv_64_rela(struct module * me,u32 * location,Elf_Addr v)41 static int apply_r_riscv_64_rela(struct module *me, u32 *location, Elf_Addr v)
42 {
43 *(u64 *)location = v;
44 return 0;
45 }
46
apply_r_riscv_branch_rela(struct module * me,u32 * location,Elf_Addr v)47 static int apply_r_riscv_branch_rela(struct module *me, u32 *location,
48 Elf_Addr v)
49 {
50 ptrdiff_t offset = (void *)v - (void *)location;
51 u32 imm12 = (offset & 0x1000) << (31 - 12);
52 u32 imm11 = (offset & 0x800) >> (11 - 7);
53 u32 imm10_5 = (offset & 0x7e0) << (30 - 10);
54 u32 imm4_1 = (offset & 0x1e) << (11 - 4);
55
56 *location = (*location & 0x1fff07f) | imm12 | imm11 | imm10_5 | imm4_1;
57 return 0;
58 }
59
apply_r_riscv_jal_rela(struct module * me,u32 * location,Elf_Addr v)60 static int apply_r_riscv_jal_rela(struct module *me, u32 *location,
61 Elf_Addr v)
62 {
63 ptrdiff_t offset = (void *)v - (void *)location;
64 u32 imm20 = (offset & 0x100000) << (31 - 20);
65 u32 imm19_12 = (offset & 0xff000);
66 u32 imm11 = (offset & 0x800) << (20 - 11);
67 u32 imm10_1 = (offset & 0x7fe) << (30 - 10);
68
69 *location = (*location & 0xfff) | imm20 | imm19_12 | imm11 | imm10_1;
70 return 0;
71 }
72
apply_r_riscv_rvc_branch_rela(struct module * me,u32 * location,Elf_Addr v)73 static int apply_r_riscv_rvc_branch_rela(struct module *me, u32 *location,
74 Elf_Addr v)
75 {
76 ptrdiff_t offset = (void *)v - (void *)location;
77 u16 imm8 = (offset & 0x100) << (12 - 8);
78 u16 imm7_6 = (offset & 0xc0) >> (6 - 5);
79 u16 imm5 = (offset & 0x20) >> (5 - 2);
80 u16 imm4_3 = (offset & 0x18) << (12 - 5);
81 u16 imm2_1 = (offset & 0x6) << (12 - 10);
82
83 *(u16 *)location = (*(u16 *)location & 0xe383) |
84 imm8 | imm7_6 | imm5 | imm4_3 | imm2_1;
85 return 0;
86 }
87
apply_r_riscv_rvc_jump_rela(struct module * me,u32 * location,Elf_Addr v)88 static int apply_r_riscv_rvc_jump_rela(struct module *me, u32 *location,
89 Elf_Addr v)
90 {
91 ptrdiff_t offset = (void *)v - (void *)location;
92 u16 imm11 = (offset & 0x800) << (12 - 11);
93 u16 imm10 = (offset & 0x400) >> (10 - 8);
94 u16 imm9_8 = (offset & 0x300) << (12 - 11);
95 u16 imm7 = (offset & 0x80) >> (7 - 6);
96 u16 imm6 = (offset & 0x40) << (12 - 11);
97 u16 imm5 = (offset & 0x20) >> (5 - 2);
98 u16 imm4 = (offset & 0x10) << (12 - 5);
99 u16 imm3_1 = (offset & 0xe) << (12 - 10);
100
101 *(u16 *)location = (*(u16 *)location & 0xe003) |
102 imm11 | imm10 | imm9_8 | imm7 | imm6 | imm5 | imm4 | imm3_1;
103 return 0;
104 }
105
apply_r_riscv_pcrel_hi20_rela(struct module * me,u32 * location,Elf_Addr v)106 static int apply_r_riscv_pcrel_hi20_rela(struct module *me, u32 *location,
107 Elf_Addr v)
108 {
109 ptrdiff_t offset = (void *)v - (void *)location;
110 s32 hi20;
111
112 if (!riscv_insn_valid_32bit_offset(offset)) {
113 pr_err(
114 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
115 me->name, (long long)v, location);
116 return -EINVAL;
117 }
118
119 hi20 = (offset + 0x800) & 0xfffff000;
120 *location = (*location & 0xfff) | hi20;
121 return 0;
122 }
123
apply_r_riscv_pcrel_lo12_i_rela(struct module * me,u32 * location,Elf_Addr v)124 static int apply_r_riscv_pcrel_lo12_i_rela(struct module *me, u32 *location,
125 Elf_Addr v)
126 {
127 /*
128 * v is the lo12 value to fill. It is calculated before calling this
129 * handler.
130 */
131 *location = (*location & 0xfffff) | ((v & 0xfff) << 20);
132 return 0;
133 }
134
apply_r_riscv_pcrel_lo12_s_rela(struct module * me,u32 * location,Elf_Addr v)135 static int apply_r_riscv_pcrel_lo12_s_rela(struct module *me, u32 *location,
136 Elf_Addr v)
137 {
138 /*
139 * v is the lo12 value to fill. It is calculated before calling this
140 * handler.
141 */
142 u32 imm11_5 = (v & 0xfe0) << (31 - 11);
143 u32 imm4_0 = (v & 0x1f) << (11 - 4);
144
145 *location = (*location & 0x1fff07f) | imm11_5 | imm4_0;
146 return 0;
147 }
148
apply_r_riscv_hi20_rela(struct module * me,u32 * location,Elf_Addr v)149 static int apply_r_riscv_hi20_rela(struct module *me, u32 *location,
150 Elf_Addr v)
151 {
152 s32 hi20;
153
154 if (IS_ENABLED(CONFIG_CMODEL_MEDLOW)) {
155 pr_err(
156 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
157 me->name, (long long)v, location);
158 return -EINVAL;
159 }
160
161 hi20 = ((s32)v + 0x800) & 0xfffff000;
162 *location = (*location & 0xfff) | hi20;
163 return 0;
164 }
165
apply_r_riscv_lo12_i_rela(struct module * me,u32 * location,Elf_Addr v)166 static int apply_r_riscv_lo12_i_rela(struct module *me, u32 *location,
167 Elf_Addr v)
168 {
169 /* Skip medlow checking because of filtering by HI20 already */
170 s32 hi20 = ((s32)v + 0x800) & 0xfffff000;
171 s32 lo12 = ((s32)v - hi20);
172 *location = (*location & 0xfffff) | ((lo12 & 0xfff) << 20);
173 return 0;
174 }
175
apply_r_riscv_lo12_s_rela(struct module * me,u32 * location,Elf_Addr v)176 static int apply_r_riscv_lo12_s_rela(struct module *me, u32 *location,
177 Elf_Addr v)
178 {
179 /* Skip medlow checking because of filtering by HI20 already */
180 s32 hi20 = ((s32)v + 0x800) & 0xfffff000;
181 s32 lo12 = ((s32)v - hi20);
182 u32 imm11_5 = (lo12 & 0xfe0) << (31 - 11);
183 u32 imm4_0 = (lo12 & 0x1f) << (11 - 4);
184 *location = (*location & 0x1fff07f) | imm11_5 | imm4_0;
185 return 0;
186 }
187
apply_r_riscv_got_hi20_rela(struct module * me,u32 * location,Elf_Addr v)188 static int apply_r_riscv_got_hi20_rela(struct module *me, u32 *location,
189 Elf_Addr v)
190 {
191 ptrdiff_t offset = (void *)v - (void *)location;
192 s32 hi20;
193
194 /* Always emit the got entry */
195 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) {
196 offset = module_emit_got_entry(me, v);
197 offset = (void *)offset - (void *)location;
198 } else {
199 pr_err(
200 "%s: can not generate the GOT entry for symbol = %016llx from PC = %p\n",
201 me->name, (long long)v, location);
202 return -EINVAL;
203 }
204
205 hi20 = (offset + 0x800) & 0xfffff000;
206 *location = (*location & 0xfff) | hi20;
207 return 0;
208 }
209
apply_r_riscv_call_plt_rela(struct module * me,u32 * location,Elf_Addr v)210 static int apply_r_riscv_call_plt_rela(struct module *me, u32 *location,
211 Elf_Addr v)
212 {
213 ptrdiff_t offset = (void *)v - (void *)location;
214 u32 hi20, lo12;
215
216 if (!riscv_insn_valid_32bit_offset(offset)) {
217 /* Only emit the plt entry if offset over 32-bit range */
218 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) {
219 offset = module_emit_plt_entry(me, v);
220 offset = (void *)offset - (void *)location;
221 } else {
222 pr_err(
223 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
224 me->name, (long long)v, location);
225 return -EINVAL;
226 }
227 }
228
229 hi20 = (offset + 0x800) & 0xfffff000;
230 lo12 = (offset - hi20) & 0xfff;
231 *location = (*location & 0xfff) | hi20;
232 *(location + 1) = (*(location + 1) & 0xfffff) | (lo12 << 20);
233 return 0;
234 }
235
apply_r_riscv_call_rela(struct module * me,u32 * location,Elf_Addr v)236 static int apply_r_riscv_call_rela(struct module *me, u32 *location,
237 Elf_Addr v)
238 {
239 ptrdiff_t offset = (void *)v - (void *)location;
240 u32 hi20, lo12;
241
242 if (!riscv_insn_valid_32bit_offset(offset)) {
243 pr_err(
244 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
245 me->name, (long long)v, location);
246 return -EINVAL;
247 }
248
249 hi20 = (offset + 0x800) & 0xfffff000;
250 lo12 = (offset - hi20) & 0xfff;
251 *location = (*location & 0xfff) | hi20;
252 *(location + 1) = (*(location + 1) & 0xfffff) | (lo12 << 20);
253 return 0;
254 }
255
apply_r_riscv_relax_rela(struct module * me,u32 * location,Elf_Addr v)256 static int apply_r_riscv_relax_rela(struct module *me, u32 *location,
257 Elf_Addr v)
258 {
259 return 0;
260 }
261
apply_r_riscv_align_rela(struct module * me,u32 * location,Elf_Addr v)262 static int apply_r_riscv_align_rela(struct module *me, u32 *location,
263 Elf_Addr v)
264 {
265 pr_err(
266 "%s: The unexpected relocation type 'R_RISCV_ALIGN' from PC = %p\n",
267 me->name, location);
268 return -EINVAL;
269 }
270
apply_r_riscv_add16_rela(struct module * me,u32 * location,Elf_Addr v)271 static int apply_r_riscv_add16_rela(struct module *me, u32 *location,
272 Elf_Addr v)
273 {
274 *(u16 *)location += (u16)v;
275 return 0;
276 }
277
apply_r_riscv_add32_rela(struct module * me,u32 * location,Elf_Addr v)278 static int apply_r_riscv_add32_rela(struct module *me, u32 *location,
279 Elf_Addr v)
280 {
281 *(u32 *)location += (u32)v;
282 return 0;
283 }
284
apply_r_riscv_add64_rela(struct module * me,u32 * location,Elf_Addr v)285 static int apply_r_riscv_add64_rela(struct module *me, u32 *location,
286 Elf_Addr v)
287 {
288 *(u64 *)location += (u64)v;
289 return 0;
290 }
291
apply_r_riscv_sub16_rela(struct module * me,u32 * location,Elf_Addr v)292 static int apply_r_riscv_sub16_rela(struct module *me, u32 *location,
293 Elf_Addr v)
294 {
295 *(u16 *)location -= (u16)v;
296 return 0;
297 }
298
apply_r_riscv_sub32_rela(struct module * me,u32 * location,Elf_Addr v)299 static int apply_r_riscv_sub32_rela(struct module *me, u32 *location,
300 Elf_Addr v)
301 {
302 *(u32 *)location -= (u32)v;
303 return 0;
304 }
305
apply_r_riscv_sub64_rela(struct module * me,u32 * location,Elf_Addr v)306 static int apply_r_riscv_sub64_rela(struct module *me, u32 *location,
307 Elf_Addr v)
308 {
309 *(u64 *)location -= (u64)v;
310 return 0;
311 }
312
313 static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
314 Elf_Addr v) = {
315 [R_RISCV_32] = apply_r_riscv_32_rela,
316 [R_RISCV_64] = apply_r_riscv_64_rela,
317 [R_RISCV_BRANCH] = apply_r_riscv_branch_rela,
318 [R_RISCV_JAL] = apply_r_riscv_jal_rela,
319 [R_RISCV_RVC_BRANCH] = apply_r_riscv_rvc_branch_rela,
320 [R_RISCV_RVC_JUMP] = apply_r_riscv_rvc_jump_rela,
321 [R_RISCV_PCREL_HI20] = apply_r_riscv_pcrel_hi20_rela,
322 [R_RISCV_PCREL_LO12_I] = apply_r_riscv_pcrel_lo12_i_rela,
323 [R_RISCV_PCREL_LO12_S] = apply_r_riscv_pcrel_lo12_s_rela,
324 [R_RISCV_HI20] = apply_r_riscv_hi20_rela,
325 [R_RISCV_LO12_I] = apply_r_riscv_lo12_i_rela,
326 [R_RISCV_LO12_S] = apply_r_riscv_lo12_s_rela,
327 [R_RISCV_GOT_HI20] = apply_r_riscv_got_hi20_rela,
328 [R_RISCV_CALL_PLT] = apply_r_riscv_call_plt_rela,
329 [R_RISCV_CALL] = apply_r_riscv_call_rela,
330 [R_RISCV_RELAX] = apply_r_riscv_relax_rela,
331 [R_RISCV_ALIGN] = apply_r_riscv_align_rela,
332 [R_RISCV_ADD16] = apply_r_riscv_add16_rela,
333 [R_RISCV_ADD32] = apply_r_riscv_add32_rela,
334 [R_RISCV_ADD64] = apply_r_riscv_add64_rela,
335 [R_RISCV_SUB16] = apply_r_riscv_sub16_rela,
336 [R_RISCV_SUB32] = apply_r_riscv_sub32_rela,
337 [R_RISCV_SUB64] = apply_r_riscv_sub64_rela,
338 };
339
apply_relocate_add(Elf_Shdr * sechdrs,const char * strtab,unsigned int symindex,unsigned int relsec,struct module * me)340 int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
341 unsigned int symindex, unsigned int relsec,
342 struct module *me)
343 {
344 Elf_Rela *rel = (void *) sechdrs[relsec].sh_addr;
345 int (*handler)(struct module *me, u32 *location, Elf_Addr v);
346 Elf_Sym *sym;
347 u32 *location;
348 unsigned int i, type;
349 Elf_Addr v;
350 int res;
351
352 pr_debug("Applying relocate section %u to %u\n", relsec,
353 sechdrs[relsec].sh_info);
354
355 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
356 /* This is where to make the change */
357 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
358 + rel[i].r_offset;
359 /* This is the symbol it is referring to */
360 sym = (Elf_Sym *)sechdrs[symindex].sh_addr
361 + ELF_RISCV_R_SYM(rel[i].r_info);
362 if (IS_ERR_VALUE(sym->st_value)) {
363 /* Ignore unresolved weak symbol */
364 if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
365 continue;
366 pr_warn("%s: Unknown symbol %s\n",
367 me->name, strtab + sym->st_name);
368 return -ENOENT;
369 }
370
371 type = ELF_RISCV_R_TYPE(rel[i].r_info);
372
373 if (type < ARRAY_SIZE(reloc_handlers_rela))
374 handler = reloc_handlers_rela[type];
375 else
376 handler = NULL;
377
378 if (!handler) {
379 pr_err("%s: Unknown relocation type %u\n",
380 me->name, type);
381 return -EINVAL;
382 }
383
384 v = sym->st_value + rel[i].r_addend;
385
386 if (type == R_RISCV_PCREL_LO12_I || type == R_RISCV_PCREL_LO12_S) {
387 unsigned int j;
388
389 for (j = 0; j < sechdrs[relsec].sh_size / sizeof(*rel); j++) {
390 unsigned long hi20_loc =
391 sechdrs[sechdrs[relsec].sh_info].sh_addr
392 + rel[j].r_offset;
393 u32 hi20_type = ELF_RISCV_R_TYPE(rel[j].r_info);
394
395 /* Find the corresponding HI20 relocation entry */
396 if (hi20_loc == sym->st_value
397 && (hi20_type == R_RISCV_PCREL_HI20
398 || hi20_type == R_RISCV_GOT_HI20)) {
399 s32 hi20, lo12;
400 Elf_Sym *hi20_sym =
401 (Elf_Sym *)sechdrs[symindex].sh_addr
402 + ELF_RISCV_R_SYM(rel[j].r_info);
403 unsigned long hi20_sym_val =
404 hi20_sym->st_value
405 + rel[j].r_addend;
406
407 /* Calculate lo12 */
408 size_t offset = hi20_sym_val - hi20_loc;
409 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)
410 && hi20_type == R_RISCV_GOT_HI20) {
411 offset = module_emit_got_entry(
412 me, hi20_sym_val);
413 offset = offset - hi20_loc;
414 }
415 hi20 = (offset + 0x800) & 0xfffff000;
416 lo12 = offset - hi20;
417 v = lo12;
418
419 break;
420 }
421 }
422 if (j == sechdrs[relsec].sh_size / sizeof(*rel)) {
423 pr_err(
424 "%s: Can not find HI20 relocation information\n",
425 me->name);
426 return -EINVAL;
427 }
428 }
429
430 res = handler(me, location, v);
431 if (res)
432 return res;
433 }
434
435 return 0;
436 }
437
438 #if defined(CONFIG_MMU) && defined(CONFIG_64BIT)
module_alloc(unsigned long size)439 void *module_alloc(unsigned long size)
440 {
441 return __vmalloc_node_range(size, 1, MODULES_VADDR,
442 MODULES_END, GFP_KERNEL,
443 PAGE_KERNEL, 0, NUMA_NO_NODE,
444 __builtin_return_address(0));
445 }
446 #endif
447
module_finalize(const Elf_Ehdr * hdr,const Elf_Shdr * sechdrs,struct module * me)448 int module_finalize(const Elf_Ehdr *hdr,
449 const Elf_Shdr *sechdrs,
450 struct module *me)
451 {
452 const Elf_Shdr *s;
453
454 s = find_section(hdr, sechdrs, ".alternative");
455 if (s)
456 apply_module_alternatives((void *)s->sh_addr, s->sh_size);
457
458 return 0;
459 }
460
