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1/*
2 * This program is free software; you can redistribute it and/or modify
3 * it under the terms of the GNU General Public License as published by
4 * the Free Software Foundation; either version 2 of the License, or
5 * (at your option) any later version.
6 *
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 * GNU General Public License for more details.
11 *
12 * Copyright (C) 2017 Zihao Yu
13 */
14
15#include <linux/elf.h>
16#include <linux/err.h>
17#include <linux/errno.h>
18#include <linux/moduleloader.h>
19
20static int apply_r_riscv_64_rela(struct module *me, u32 *location, Elf_Addr v)
21{
22 *(u64 *)location = v;
23 return 0;
24}
25
26static int apply_r_riscv_branch_rela(struct module *me, u32 *location,
27 Elf_Addr v)
28{
29 s64 offset = (void *)v - (void *)location;
30 u32 imm12 = (offset & 0x1000) << (31 - 12);
31 u32 imm11 = (offset & 0x800) >> (11 - 7);
32 u32 imm10_5 = (offset & 0x7e0) << (30 - 10);
33 u32 imm4_1 = (offset & 0x1e) << (11 - 4);
34
35 *location = (*location & 0x1fff07f) | imm12 | imm11 | imm10_5 | imm4_1;
36 return 0;
37}
38
39static int apply_r_riscv_jal_rela(struct module *me, u32 *location,
40 Elf_Addr v)
41{
42 s64 offset = (void *)v - (void *)location;
43 u32 imm20 = (offset & 0x100000) << (31 - 20);
44 u32 imm19_12 = (offset & 0xff000);
45 u32 imm11 = (offset & 0x800) << (20 - 11);
46 u32 imm10_1 = (offset & 0x7fe) << (30 - 10);
47
48 *location = (*location & 0xfff) | imm20 | imm19_12 | imm11 | imm10_1;
49 return 0;
50}
51
52static int apply_r_riscv_rcv_branch_rela(struct module *me, u32 *location,
53 Elf_Addr v)
54{
55 s64 offset = (void *)v - (void *)location;
56 u16 imm8 = (offset & 0x100) << (12 - 8);
57 u16 imm7_6 = (offset & 0xc0) >> (6 - 5);
58 u16 imm5 = (offset & 0x20) >> (5 - 2);
59 u16 imm4_3 = (offset & 0x18) << (12 - 5);
60 u16 imm2_1 = (offset & 0x6) << (12 - 10);
61
62 *(u16 *)location = (*(u16 *)location & 0xe383) |
63 imm8 | imm7_6 | imm5 | imm4_3 | imm2_1;
64 return 0;
65}
66
67static int apply_r_riscv_rvc_jump_rela(struct module *me, u32 *location,
68 Elf_Addr v)
69{
70 s64 offset = (void *)v - (void *)location;
71 u16 imm11 = (offset & 0x800) << (12 - 11);
72 u16 imm10 = (offset & 0x400) >> (10 - 8);
73 u16 imm9_8 = (offset & 0x300) << (12 - 11);
74 u16 imm7 = (offset & 0x80) >> (7 - 6);
75 u16 imm6 = (offset & 0x40) << (12 - 11);
76 u16 imm5 = (offset & 0x20) >> (5 - 2);
77 u16 imm4 = (offset & 0x10) << (12 - 5);
78 u16 imm3_1 = (offset & 0xe) << (12 - 10);
79
80 *(u16 *)location = (*(u16 *)location & 0xe003) |
81 imm11 | imm10 | imm9_8 | imm7 | imm6 | imm5 | imm4 | imm3_1;
82 return 0;
83}
84
85static int apply_r_riscv_pcrel_hi20_rela(struct module *me, u32 *location,
86 Elf_Addr v)
87{
88 s64 offset = (void *)v - (void *)location;
89 s32 hi20;
90
91 if (offset != (s32)offset) {
92 pr_err(
93 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
94 me->name, v, location);
95 return -EINVAL;
96 }
97
98 hi20 = (offset + 0x800) & 0xfffff000;
99 *location = (*location & 0xfff) | hi20;
100 return 0;
101}
102
103static int apply_r_riscv_pcrel_lo12_i_rela(struct module *me, u32 *location,
104 Elf_Addr v)
105{
106 /*
107 * v is the lo12 value to fill. It is calculated before calling this
108 * handler.
109 */
110 *location = (*location & 0xfffff) | ((v & 0xfff) << 20);
111 return 0;
112}
113
114static int apply_r_riscv_pcrel_lo12_s_rela(struct module *me, u32 *location,
115 Elf_Addr v)
116{
117 /*
118 * v is the lo12 value to fill. It is calculated before calling this
119 * handler.
120 */
121 u32 imm11_5 = (v & 0xfe0) << (31 - 11);
122 u32 imm4_0 = (v & 0x1f) << (11 - 4);
123
124 *location = (*location & 0x1fff07f) | imm11_5 | imm4_0;
125 return 0;
126}
127
128static int apply_r_riscv_hi20_rela(struct module *me, u32 *location,
129 Elf_Addr v)
130{
131 s32 hi20;
132
133 if (IS_ENABLED(CMODEL_MEDLOW)) {
134 pr_err(
135 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
136 me->name, v, location);
137 return -EINVAL;
138 }
139
140 hi20 = ((s32)v + 0x800) & 0xfffff000;
141 *location = (*location & 0xfff) | hi20;
142 return 0;
143}
144
145static int apply_r_riscv_lo12_i_rela(struct module *me, u32 *location,
146 Elf_Addr v)
147{
148 /* Skip medlow checking because of filtering by HI20 already */
149 s32 hi20 = ((s32)v + 0x800) & 0xfffff000;
150 s32 lo12 = ((s32)v - hi20);
151 *location = (*location & 0xfffff) | ((lo12 & 0xfff) << 20);
152 return 0;
153}
154
155static int apply_r_riscv_lo12_s_rela(struct module *me, u32 *location,
156 Elf_Addr v)
157{
158 /* Skip medlow checking because of filtering by HI20 already */
159 s32 hi20 = ((s32)v + 0x800) & 0xfffff000;
160 s32 lo12 = ((s32)v - hi20);
161 u32 imm11_5 = (lo12 & 0xfe0) << (31 - 11);
162 u32 imm4_0 = (lo12 & 0x1f) << (11 - 4);
163 *location = (*location & 0x1fff07f) | imm11_5 | imm4_0;
164 return 0;
165}
166
167static int apply_r_riscv_got_hi20_rela(struct module *me, u32 *location,
168 Elf_Addr v)
169{
170 s64 offset = (void *)v - (void *)location;
171 s32 hi20;
172
173 /* Always emit the got entry */
174 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) {
175 offset = module_emit_got_entry(me, v);
176 offset = (void *)offset - (void *)location;
177 } else {
178 pr_err(
179 "%s: can not generate the GOT entry for symbol = %016llx from PC = %p\n",
180 me->name, v, location);
181 return -EINVAL;
182 }
183
184 hi20 = (offset + 0x800) & 0xfffff000;
185 *location = (*location & 0xfff) | hi20;
186 return 0;
187}
188
189static int apply_r_riscv_call_plt_rela(struct module *me, u32 *location,
190 Elf_Addr v)
191{
192 s64 offset = (void *)v - (void *)location;
193 s32 fill_v = offset;
194 u32 hi20, lo12;
195
196 if (offset != fill_v) {
197 /* Only emit the plt entry if offset over 32-bit range */
198 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) {
199 offset = module_emit_plt_entry(me, v);
200 offset = (void *)offset - (void *)location;
201 } else {
202 pr_err(
203 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
204 me->name, v, location);
205 return -EINVAL;
206 }
207 }
208
209 hi20 = (offset + 0x800) & 0xfffff000;
210 lo12 = (offset - hi20) & 0xfff;
211 *location = (*location & 0xfff) | hi20;
212 *(location + 1) = (*(location + 1) & 0xfffff) | (lo12 << 20);
213 return 0;
214}
215
216static int apply_r_riscv_call_rela(struct module *me, u32 *location,
217 Elf_Addr v)
218{
219 s64 offset = (void *)v - (void *)location;
220 s32 fill_v = offset;
221 u32 hi20, lo12;
222
223 if (offset != fill_v) {
224 pr_err(
225 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
226 me->name, v, location);
227 return -EINVAL;
228 }
229
230 hi20 = (offset + 0x800) & 0xfffff000;
231 lo12 = (offset - hi20) & 0xfff;
232 *location = (*location & 0xfff) | hi20;
233 *(location + 1) = (*(location + 1) & 0xfffff) | (lo12 << 20);
234 return 0;
235}
236
237static int apply_r_riscv_relax_rela(struct module *me, u32 *location,
238 Elf_Addr v)
239{
240 return 0;
241}
242
243static int apply_r_riscv_align_rela(struct module *me, u32 *location,
244 Elf_Addr v)
245{
246 pr_err(
247 "%s: The unexpected relocation type 'R_RISCV_ALIGN' from PC = %p\n",
248 me->name, location);
249 return -EINVAL;
250}
251
252static int apply_r_riscv_add32_rela(struct module *me, u32 *location,
253 Elf_Addr v)
254{
255 *(u32 *)location += (*(u32 *)v);
256 return 0;
257}
258
259static int apply_r_riscv_sub32_rela(struct module *me, u32 *location,
260 Elf_Addr v)
261{
262 *(u32 *)location -= (*(u32 *)v);
263 return 0;
264}
265
266static int (*reloc_handlers_rela[]) (struct module *me, u32 *location,
267 Elf_Addr v) = {
268 [R_RISCV_64] = apply_r_riscv_64_rela,
269 [R_RISCV_BRANCH] = apply_r_riscv_branch_rela,
270 [R_RISCV_JAL] = apply_r_riscv_jal_rela,
271 [R_RISCV_RVC_BRANCH] = apply_r_riscv_rcv_branch_rela,
272 [R_RISCV_RVC_JUMP] = apply_r_riscv_rvc_jump_rela,
273 [R_RISCV_PCREL_HI20] = apply_r_riscv_pcrel_hi20_rela,
274 [R_RISCV_PCREL_LO12_I] = apply_r_riscv_pcrel_lo12_i_rela,
275 [R_RISCV_PCREL_LO12_S] = apply_r_riscv_pcrel_lo12_s_rela,
276 [R_RISCV_HI20] = apply_r_riscv_hi20_rela,
277 [R_RISCV_LO12_I] = apply_r_riscv_lo12_i_rela,
278 [R_RISCV_LO12_S] = apply_r_riscv_lo12_s_rela,
279 [R_RISCV_GOT_HI20] = apply_r_riscv_got_hi20_rela,
280 [R_RISCV_CALL_PLT] = apply_r_riscv_call_plt_rela,
281 [R_RISCV_CALL] = apply_r_riscv_call_rela,
282 [R_RISCV_RELAX] = apply_r_riscv_relax_rela,
283 [R_RISCV_ALIGN] = apply_r_riscv_align_rela,
284 [R_RISCV_ADD32] = apply_r_riscv_add32_rela,
285 [R_RISCV_SUB32] = apply_r_riscv_sub32_rela,
286};
287
288int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
289 unsigned int symindex, unsigned int relsec,
290 struct module *me)
291{
292 Elf_Rela *rel = (void *) sechdrs[relsec].sh_addr;
293 int (*handler)(struct module *me, u32 *location, Elf_Addr v);
294 Elf_Sym *sym;
295 u32 *location;
296 unsigned int i, type;
297 Elf_Addr v;
298 int res;
299
300 pr_debug("Applying relocate section %u to %u\n", relsec,
301 sechdrs[relsec].sh_info);
302
303 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
304 /* This is where to make the change */
305 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
306 + rel[i].r_offset;
307 /* This is the symbol it is referring to */
308 sym = (Elf_Sym *)sechdrs[symindex].sh_addr
309 + ELF_RISCV_R_SYM(rel[i].r_info);
310 if (IS_ERR_VALUE(sym->st_value)) {
311 /* Ignore unresolved weak symbol */
312 if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
313 continue;
314 pr_warning("%s: Unknown symbol %s\n",
315 me->name, strtab + sym->st_name);
316 return -ENOENT;
317 }
318
319 type = ELF_RISCV_R_TYPE(rel[i].r_info);
320
321 if (type < ARRAY_SIZE(reloc_handlers_rela))
322 handler = reloc_handlers_rela[type];
323 else
324 handler = NULL;
325
326 if (!handler) {
327 pr_err("%s: Unknown relocation type %u\n",
328 me->name, type);
329 return -EINVAL;
330 }
331
332 v = sym->st_value + rel[i].r_addend;
333
334 if (type == R_RISCV_PCREL_LO12_I || type == R_RISCV_PCREL_LO12_S) {
335 unsigned int j;
336
337 for (j = 0; j < sechdrs[relsec].sh_size / sizeof(*rel); j++) {
338 u64 hi20_loc =
339 sechdrs[sechdrs[relsec].sh_info].sh_addr
340 + rel[j].r_offset;
341 u32 hi20_type = ELF_RISCV_R_TYPE(rel[j].r_info);
342
343 /* Find the corresponding HI20 relocation entry */
344 if (hi20_loc == sym->st_value
345 && (hi20_type == R_RISCV_PCREL_HI20
346 || hi20_type == R_RISCV_GOT_HI20)) {
347 s32 hi20, lo12;
348 Elf_Sym *hi20_sym =
349 (Elf_Sym *)sechdrs[symindex].sh_addr
350 + ELF_RISCV_R_SYM(rel[j].r_info);
351 u64 hi20_sym_val =
352 hi20_sym->st_value
353 + rel[j].r_addend;
354
355 /* Calculate lo12 */
356 u64 offset = hi20_sym_val - hi20_loc;
357 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)
358 && hi20_type == R_RISCV_GOT_HI20) {
359 offset = module_emit_got_entry(
360 me, hi20_sym_val);
361 offset = offset - hi20_loc;
362 }
363 hi20 = (offset + 0x800) & 0xfffff000;
364 lo12 = offset - hi20;
365 v = lo12;
366
367 break;
368 }
369 }
370 if (j == sechdrs[relsec].sh_size / sizeof(*rel)) {
371 pr_err(
372 "%s: Can not find HI20 relocation information\n",
373 me->name);
374 return -EINVAL;
375 }
376 }
377
378 res = handler(me, location, v);
379 if (res)
380 return res;
381 }
382
383 return 0;
384}
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/hashtable.h>
11#include <linux/kernel.h>
12#include <linux/log2.h>
13#include <linux/moduleloader.h>
14#include <linux/sizes.h>
15#include <linux/pgtable.h>
16#include <asm/alternative.h>
17#include <asm/sections.h>
18
19struct used_bucket {
20 struct list_head head;
21 struct hlist_head *bucket;
22};
23
24struct relocation_head {
25 struct hlist_node node;
26 struct list_head rel_entry;
27 void *location;
28};
29
30struct relocation_entry {
31 struct list_head head;
32 Elf_Addr value;
33 unsigned int type;
34};
35
36struct relocation_handlers {
37 int (*reloc_handler)(struct module *me, void *location, Elf_Addr v);
38 int (*accumulate_handler)(struct module *me, void *location,
39 long buffer);
40};
41
42/*
43 * The auipc+jalr instruction pair can reach any PC-relative offset
44 * in the range [-2^31 - 2^11, 2^31 - 2^11)
45 */
46static bool riscv_insn_valid_32bit_offset(ptrdiff_t val)
47{
48#ifdef CONFIG_32BIT
49 return true;
50#else
51 return (-(1L << 31) - (1L << 11)) <= val && val < ((1L << 31) - (1L << 11));
52#endif
53}
54
55static int riscv_insn_rmw(void *location, u32 keep, u32 set)
56{
57 __le16 *parcel = location;
58 u32 insn = (u32)le16_to_cpu(parcel[0]) | (u32)le16_to_cpu(parcel[1]) << 16;
59
60 insn &= keep;
61 insn |= set;
62
63 parcel[0] = cpu_to_le16(insn);
64 parcel[1] = cpu_to_le16(insn >> 16);
65 return 0;
66}
67
68static int riscv_insn_rvc_rmw(void *location, u16 keep, u16 set)
69{
70 __le16 *parcel = location;
71 u16 insn = le16_to_cpu(*parcel);
72
73 insn &= keep;
74 insn |= set;
75
76 *parcel = cpu_to_le16(insn);
77 return 0;
78}
79
80static int apply_r_riscv_32_rela(struct module *me, void *location, Elf_Addr v)
81{
82 if (v != (u32)v) {
83 pr_err("%s: value %016llx out of range for 32-bit field\n",
84 me->name, (long long)v);
85 return -EINVAL;
86 }
87 *(u32 *)location = v;
88 return 0;
89}
90
91static int apply_r_riscv_64_rela(struct module *me, void *location, Elf_Addr v)
92{
93 *(u64 *)location = v;
94 return 0;
95}
96
97static int apply_r_riscv_branch_rela(struct module *me, void *location,
98 Elf_Addr v)
99{
100 ptrdiff_t offset = (void *)v - location;
101 u32 imm12 = (offset & 0x1000) << (31 - 12);
102 u32 imm11 = (offset & 0x800) >> (11 - 7);
103 u32 imm10_5 = (offset & 0x7e0) << (30 - 10);
104 u32 imm4_1 = (offset & 0x1e) << (11 - 4);
105
106 return riscv_insn_rmw(location, 0x1fff07f, imm12 | imm11 | imm10_5 | imm4_1);
107}
108
109static int apply_r_riscv_jal_rela(struct module *me, void *location,
110 Elf_Addr v)
111{
112 ptrdiff_t offset = (void *)v - location;
113 u32 imm20 = (offset & 0x100000) << (31 - 20);
114 u32 imm19_12 = (offset & 0xff000);
115 u32 imm11 = (offset & 0x800) << (20 - 11);
116 u32 imm10_1 = (offset & 0x7fe) << (30 - 10);
117
118 return riscv_insn_rmw(location, 0xfff, imm20 | imm19_12 | imm11 | imm10_1);
119}
120
121static int apply_r_riscv_rvc_branch_rela(struct module *me, void *location,
122 Elf_Addr v)
123{
124 ptrdiff_t offset = (void *)v - location;
125 u16 imm8 = (offset & 0x100) << (12 - 8);
126 u16 imm7_6 = (offset & 0xc0) >> (6 - 5);
127 u16 imm5 = (offset & 0x20) >> (5 - 2);
128 u16 imm4_3 = (offset & 0x18) << (12 - 5);
129 u16 imm2_1 = (offset & 0x6) << (12 - 10);
130
131 return riscv_insn_rvc_rmw(location, 0xe383,
132 imm8 | imm7_6 | imm5 | imm4_3 | imm2_1);
133}
134
135static int apply_r_riscv_rvc_jump_rela(struct module *me, void *location,
136 Elf_Addr v)
137{
138 ptrdiff_t offset = (void *)v - location;
139 u16 imm11 = (offset & 0x800) << (12 - 11);
140 u16 imm10 = (offset & 0x400) >> (10 - 8);
141 u16 imm9_8 = (offset & 0x300) << (12 - 11);
142 u16 imm7 = (offset & 0x80) >> (7 - 6);
143 u16 imm6 = (offset & 0x40) << (12 - 11);
144 u16 imm5 = (offset & 0x20) >> (5 - 2);
145 u16 imm4 = (offset & 0x10) << (12 - 5);
146 u16 imm3_1 = (offset & 0xe) << (12 - 10);
147
148 return riscv_insn_rvc_rmw(location, 0xe003,
149 imm11 | imm10 | imm9_8 | imm7 | imm6 | imm5 | imm4 | imm3_1);
150}
151
152static int apply_r_riscv_pcrel_hi20_rela(struct module *me, void *location,
153 Elf_Addr v)
154{
155 ptrdiff_t offset = (void *)v - location;
156
157 if (!riscv_insn_valid_32bit_offset(offset)) {
158 pr_err(
159 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
160 me->name, (long long)v, location);
161 return -EINVAL;
162 }
163
164 return riscv_insn_rmw(location, 0xfff, (offset + 0x800) & 0xfffff000);
165}
166
167static int apply_r_riscv_pcrel_lo12_i_rela(struct module *me, void *location,
168 Elf_Addr v)
169{
170 /*
171 * v is the lo12 value to fill. It is calculated before calling this
172 * handler.
173 */
174 return riscv_insn_rmw(location, 0xfffff, (v & 0xfff) << 20);
175}
176
177static int apply_r_riscv_pcrel_lo12_s_rela(struct module *me, void *location,
178 Elf_Addr v)
179{
180 /*
181 * v is the lo12 value to fill. It is calculated before calling this
182 * handler.
183 */
184 u32 imm11_5 = (v & 0xfe0) << (31 - 11);
185 u32 imm4_0 = (v & 0x1f) << (11 - 4);
186
187 return riscv_insn_rmw(location, 0x1fff07f, imm11_5 | imm4_0);
188}
189
190static int apply_r_riscv_hi20_rela(struct module *me, void *location,
191 Elf_Addr v)
192{
193 if (IS_ENABLED(CONFIG_CMODEL_MEDLOW)) {
194 pr_err(
195 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
196 me->name, (long long)v, location);
197 return -EINVAL;
198 }
199
200 return riscv_insn_rmw(location, 0xfff, ((s32)v + 0x800) & 0xfffff000);
201}
202
203static int apply_r_riscv_lo12_i_rela(struct module *me, void *location,
204 Elf_Addr v)
205{
206 /* Skip medlow checking because of filtering by HI20 already */
207 s32 hi20 = ((s32)v + 0x800) & 0xfffff000;
208 s32 lo12 = ((s32)v - hi20);
209
210 return riscv_insn_rmw(location, 0xfffff, (lo12 & 0xfff) << 20);
211}
212
213static int apply_r_riscv_lo12_s_rela(struct module *me, void *location,
214 Elf_Addr v)
215{
216 /* Skip medlow checking because of filtering by HI20 already */
217 s32 hi20 = ((s32)v + 0x800) & 0xfffff000;
218 s32 lo12 = ((s32)v - hi20);
219 u32 imm11_5 = (lo12 & 0xfe0) << (31 - 11);
220 u32 imm4_0 = (lo12 & 0x1f) << (11 - 4);
221
222 return riscv_insn_rmw(location, 0x1fff07f, imm11_5 | imm4_0);
223}
224
225static int apply_r_riscv_got_hi20_rela(struct module *me, void *location,
226 Elf_Addr v)
227{
228 ptrdiff_t offset = (void *)v - location;
229
230 /* Always emit the got entry */
231 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) {
232 offset = (void *)module_emit_got_entry(me, v) - location;
233 } else {
234 pr_err(
235 "%s: can not generate the GOT entry for symbol = %016llx from PC = %p\n",
236 me->name, (long long)v, location);
237 return -EINVAL;
238 }
239
240 return riscv_insn_rmw(location, 0xfff, (offset + 0x800) & 0xfffff000);
241}
242
243static int apply_r_riscv_call_plt_rela(struct module *me, void *location,
244 Elf_Addr v)
245{
246 ptrdiff_t offset = (void *)v - location;
247 u32 hi20, lo12;
248
249 if (!riscv_insn_valid_32bit_offset(offset)) {
250 /* Only emit the plt entry if offset over 32-bit range */
251 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) {
252 offset = (void *)module_emit_plt_entry(me, v) - location;
253 } else {
254 pr_err(
255 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
256 me->name, (long long)v, location);
257 return -EINVAL;
258 }
259 }
260
261 hi20 = (offset + 0x800) & 0xfffff000;
262 lo12 = (offset - hi20) & 0xfff;
263 riscv_insn_rmw(location, 0xfff, hi20);
264 return riscv_insn_rmw(location + 4, 0xfffff, lo12 << 20);
265}
266
267static int apply_r_riscv_call_rela(struct module *me, void *location,
268 Elf_Addr v)
269{
270 ptrdiff_t offset = (void *)v - location;
271 u32 hi20, lo12;
272
273 if (!riscv_insn_valid_32bit_offset(offset)) {
274 pr_err(
275 "%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
276 me->name, (long long)v, location);
277 return -EINVAL;
278 }
279
280 hi20 = (offset + 0x800) & 0xfffff000;
281 lo12 = (offset - hi20) & 0xfff;
282 riscv_insn_rmw(location, 0xfff, hi20);
283 return riscv_insn_rmw(location + 4, 0xfffff, lo12 << 20);
284}
285
286static int apply_r_riscv_relax_rela(struct module *me, void *location,
287 Elf_Addr v)
288{
289 return 0;
290}
291
292static int apply_r_riscv_align_rela(struct module *me, void *location,
293 Elf_Addr v)
294{
295 pr_err(
296 "%s: The unexpected relocation type 'R_RISCV_ALIGN' from PC = %p\n",
297 me->name, location);
298 return -EINVAL;
299}
300
301static int apply_r_riscv_add8_rela(struct module *me, void *location, Elf_Addr v)
302{
303 *(u8 *)location += (u8)v;
304 return 0;
305}
306
307static int apply_r_riscv_add16_rela(struct module *me, void *location,
308 Elf_Addr v)
309{
310 *(u16 *)location += (u16)v;
311 return 0;
312}
313
314static int apply_r_riscv_add32_rela(struct module *me, void *location,
315 Elf_Addr v)
316{
317 *(u32 *)location += (u32)v;
318 return 0;
319}
320
321static int apply_r_riscv_add64_rela(struct module *me, void *location,
322 Elf_Addr v)
323{
324 *(u64 *)location += (u64)v;
325 return 0;
326}
327
328static int apply_r_riscv_sub8_rela(struct module *me, void *location, Elf_Addr v)
329{
330 *(u8 *)location -= (u8)v;
331 return 0;
332}
333
334static int apply_r_riscv_sub16_rela(struct module *me, void *location,
335 Elf_Addr v)
336{
337 *(u16 *)location -= (u16)v;
338 return 0;
339}
340
341static int apply_r_riscv_sub32_rela(struct module *me, void *location,
342 Elf_Addr v)
343{
344 *(u32 *)location -= (u32)v;
345 return 0;
346}
347
348static int apply_r_riscv_sub64_rela(struct module *me, void *location,
349 Elf_Addr v)
350{
351 *(u64 *)location -= (u64)v;
352 return 0;
353}
354
355static int dynamic_linking_not_supported(struct module *me, void *location,
356 Elf_Addr v)
357{
358 pr_err("%s: Dynamic linking not supported in kernel modules PC = %p\n",
359 me->name, location);
360 return -EINVAL;
361}
362
363static int tls_not_supported(struct module *me, void *location, Elf_Addr v)
364{
365 pr_err("%s: Thread local storage not supported in kernel modules PC = %p\n",
366 me->name, location);
367 return -EINVAL;
368}
369
370static int apply_r_riscv_sub6_rela(struct module *me, void *location, Elf_Addr v)
371{
372 u8 *byte = location;
373 u8 value = v;
374
375 *byte = (*byte - (value & 0x3f)) & 0x3f;
376 return 0;
377}
378
379static int apply_r_riscv_set6_rela(struct module *me, void *location, Elf_Addr v)
380{
381 u8 *byte = location;
382 u8 value = v;
383
384 *byte = (*byte & 0xc0) | (value & 0x3f);
385 return 0;
386}
387
388static int apply_r_riscv_set8_rela(struct module *me, void *location, Elf_Addr v)
389{
390 *(u8 *)location = (u8)v;
391 return 0;
392}
393
394static int apply_r_riscv_set16_rela(struct module *me, void *location,
395 Elf_Addr v)
396{
397 *(u16 *)location = (u16)v;
398 return 0;
399}
400
401static int apply_r_riscv_set32_rela(struct module *me, void *location,
402 Elf_Addr v)
403{
404 *(u32 *)location = (u32)v;
405 return 0;
406}
407
408static int apply_r_riscv_32_pcrel_rela(struct module *me, void *location,
409 Elf_Addr v)
410{
411 *(u32 *)location = v - (uintptr_t)location;
412 return 0;
413}
414
415static int apply_r_riscv_plt32_rela(struct module *me, void *location,
416 Elf_Addr v)
417{
418 ptrdiff_t offset = (void *)v - location;
419
420 if (!riscv_insn_valid_32bit_offset(offset)) {
421 /* Only emit the plt entry if offset over 32-bit range */
422 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)) {
423 offset = (void *)module_emit_plt_entry(me, v) - location;
424 } else {
425 pr_err("%s: target %016llx can not be addressed by the 32-bit offset from PC = %p\n",
426 me->name, (long long)v, location);
427 return -EINVAL;
428 }
429 }
430
431 *(u32 *)location = (u32)offset;
432 return 0;
433}
434
435static int apply_r_riscv_set_uleb128(struct module *me, void *location, Elf_Addr v)
436{
437 *(long *)location = v;
438 return 0;
439}
440
441static int apply_r_riscv_sub_uleb128(struct module *me, void *location, Elf_Addr v)
442{
443 *(long *)location -= v;
444 return 0;
445}
446
447static int apply_6_bit_accumulation(struct module *me, void *location, long buffer)
448{
449 u8 *byte = location;
450 u8 value = buffer;
451
452 if (buffer > 0x3f) {
453 pr_err("%s: value %ld out of range for 6-bit relocation.\n",
454 me->name, buffer);
455 return -EINVAL;
456 }
457
458 *byte = (*byte & 0xc0) | (value & 0x3f);
459 return 0;
460}
461
462static int apply_8_bit_accumulation(struct module *me, void *location, long buffer)
463{
464 if (buffer > U8_MAX) {
465 pr_err("%s: value %ld out of range for 8-bit relocation.\n",
466 me->name, buffer);
467 return -EINVAL;
468 }
469 *(u8 *)location = (u8)buffer;
470 return 0;
471}
472
473static int apply_16_bit_accumulation(struct module *me, void *location, long buffer)
474{
475 if (buffer > U16_MAX) {
476 pr_err("%s: value %ld out of range for 16-bit relocation.\n",
477 me->name, buffer);
478 return -EINVAL;
479 }
480 *(u16 *)location = (u16)buffer;
481 return 0;
482}
483
484static int apply_32_bit_accumulation(struct module *me, void *location, long buffer)
485{
486 if (buffer > U32_MAX) {
487 pr_err("%s: value %ld out of range for 32-bit relocation.\n",
488 me->name, buffer);
489 return -EINVAL;
490 }
491 *(u32 *)location = (u32)buffer;
492 return 0;
493}
494
495static int apply_64_bit_accumulation(struct module *me, void *location, long buffer)
496{
497 *(u64 *)location = (u64)buffer;
498 return 0;
499}
500
501static int apply_uleb128_accumulation(struct module *me, void *location, long buffer)
502{
503 /*
504 * ULEB128 is a variable length encoding. Encode the buffer into
505 * the ULEB128 data format.
506 */
507 u8 *p = location;
508
509 while (buffer != 0) {
510 u8 value = buffer & 0x7f;
511
512 buffer >>= 7;
513 value |= (!!buffer) << 7;
514
515 *p++ = value;
516 }
517 return 0;
518}
519
520/*
521 * Relocations defined in the riscv-elf-psabi-doc.
522 * This handles static linking only.
523 */
524static const struct relocation_handlers reloc_handlers[] = {
525 [R_RISCV_32] = { .reloc_handler = apply_r_riscv_32_rela },
526 [R_RISCV_64] = { .reloc_handler = apply_r_riscv_64_rela },
527 [R_RISCV_RELATIVE] = { .reloc_handler = dynamic_linking_not_supported },
528 [R_RISCV_COPY] = { .reloc_handler = dynamic_linking_not_supported },
529 [R_RISCV_JUMP_SLOT] = { .reloc_handler = dynamic_linking_not_supported },
530 [R_RISCV_TLS_DTPMOD32] = { .reloc_handler = dynamic_linking_not_supported },
531 [R_RISCV_TLS_DTPMOD64] = { .reloc_handler = dynamic_linking_not_supported },
532 [R_RISCV_TLS_DTPREL32] = { .reloc_handler = dynamic_linking_not_supported },
533 [R_RISCV_TLS_DTPREL64] = { .reloc_handler = dynamic_linking_not_supported },
534 [R_RISCV_TLS_TPREL32] = { .reloc_handler = dynamic_linking_not_supported },
535 [R_RISCV_TLS_TPREL64] = { .reloc_handler = dynamic_linking_not_supported },
536 /* 12-15 undefined */
537 [R_RISCV_BRANCH] = { .reloc_handler = apply_r_riscv_branch_rela },
538 [R_RISCV_JAL] = { .reloc_handler = apply_r_riscv_jal_rela },
539 [R_RISCV_CALL] = { .reloc_handler = apply_r_riscv_call_rela },
540 [R_RISCV_CALL_PLT] = { .reloc_handler = apply_r_riscv_call_plt_rela },
541 [R_RISCV_GOT_HI20] = { .reloc_handler = apply_r_riscv_got_hi20_rela },
542 [R_RISCV_TLS_GOT_HI20] = { .reloc_handler = tls_not_supported },
543 [R_RISCV_TLS_GD_HI20] = { .reloc_handler = tls_not_supported },
544 [R_RISCV_PCREL_HI20] = { .reloc_handler = apply_r_riscv_pcrel_hi20_rela },
545 [R_RISCV_PCREL_LO12_I] = { .reloc_handler = apply_r_riscv_pcrel_lo12_i_rela },
546 [R_RISCV_PCREL_LO12_S] = { .reloc_handler = apply_r_riscv_pcrel_lo12_s_rela },
547 [R_RISCV_HI20] = { .reloc_handler = apply_r_riscv_hi20_rela },
548 [R_RISCV_LO12_I] = { .reloc_handler = apply_r_riscv_lo12_i_rela },
549 [R_RISCV_LO12_S] = { .reloc_handler = apply_r_riscv_lo12_s_rela },
550 [R_RISCV_TPREL_HI20] = { .reloc_handler = tls_not_supported },
551 [R_RISCV_TPREL_LO12_I] = { .reloc_handler = tls_not_supported },
552 [R_RISCV_TPREL_LO12_S] = { .reloc_handler = tls_not_supported },
553 [R_RISCV_TPREL_ADD] = { .reloc_handler = tls_not_supported },
554 [R_RISCV_ADD8] = { .reloc_handler = apply_r_riscv_add8_rela,
555 .accumulate_handler = apply_8_bit_accumulation },
556 [R_RISCV_ADD16] = { .reloc_handler = apply_r_riscv_add16_rela,
557 .accumulate_handler = apply_16_bit_accumulation },
558 [R_RISCV_ADD32] = { .reloc_handler = apply_r_riscv_add32_rela,
559 .accumulate_handler = apply_32_bit_accumulation },
560 [R_RISCV_ADD64] = { .reloc_handler = apply_r_riscv_add64_rela,
561 .accumulate_handler = apply_64_bit_accumulation },
562 [R_RISCV_SUB8] = { .reloc_handler = apply_r_riscv_sub8_rela,
563 .accumulate_handler = apply_8_bit_accumulation },
564 [R_RISCV_SUB16] = { .reloc_handler = apply_r_riscv_sub16_rela,
565 .accumulate_handler = apply_16_bit_accumulation },
566 [R_RISCV_SUB32] = { .reloc_handler = apply_r_riscv_sub32_rela,
567 .accumulate_handler = apply_32_bit_accumulation },
568 [R_RISCV_SUB64] = { .reloc_handler = apply_r_riscv_sub64_rela,
569 .accumulate_handler = apply_64_bit_accumulation },
570 /* 41-42 reserved for future standard use */
571 [R_RISCV_ALIGN] = { .reloc_handler = apply_r_riscv_align_rela },
572 [R_RISCV_RVC_BRANCH] = { .reloc_handler = apply_r_riscv_rvc_branch_rela },
573 [R_RISCV_RVC_JUMP] = { .reloc_handler = apply_r_riscv_rvc_jump_rela },
574 /* 46-50 reserved for future standard use */
575 [R_RISCV_RELAX] = { .reloc_handler = apply_r_riscv_relax_rela },
576 [R_RISCV_SUB6] = { .reloc_handler = apply_r_riscv_sub6_rela,
577 .accumulate_handler = apply_6_bit_accumulation },
578 [R_RISCV_SET6] = { .reloc_handler = apply_r_riscv_set6_rela,
579 .accumulate_handler = apply_6_bit_accumulation },
580 [R_RISCV_SET8] = { .reloc_handler = apply_r_riscv_set8_rela,
581 .accumulate_handler = apply_8_bit_accumulation },
582 [R_RISCV_SET16] = { .reloc_handler = apply_r_riscv_set16_rela,
583 .accumulate_handler = apply_16_bit_accumulation },
584 [R_RISCV_SET32] = { .reloc_handler = apply_r_riscv_set32_rela,
585 .accumulate_handler = apply_32_bit_accumulation },
586 [R_RISCV_32_PCREL] = { .reloc_handler = apply_r_riscv_32_pcrel_rela },
587 [R_RISCV_IRELATIVE] = { .reloc_handler = dynamic_linking_not_supported },
588 [R_RISCV_PLT32] = { .reloc_handler = apply_r_riscv_plt32_rela },
589 [R_RISCV_SET_ULEB128] = { .reloc_handler = apply_r_riscv_set_uleb128,
590 .accumulate_handler = apply_uleb128_accumulation },
591 [R_RISCV_SUB_ULEB128] = { .reloc_handler = apply_r_riscv_sub_uleb128,
592 .accumulate_handler = apply_uleb128_accumulation },
593 /* 62-191 reserved for future standard use */
594 /* 192-255 nonstandard ABI extensions */
595};
596
597static void
598process_accumulated_relocations(struct module *me,
599 struct hlist_head **relocation_hashtable,
600 struct list_head *used_buckets_list)
601{
602 /*
603 * Only ADD/SUB/SET/ULEB128 should end up here.
604 *
605 * Each bucket may have more than one relocation location. All
606 * relocations for a location are stored in a list in a bucket.
607 *
608 * Relocations are applied to a temp variable before being stored to the
609 * provided location to check for overflow. This also allows ULEB128 to
610 * properly decide how many entries are needed before storing to
611 * location. The final value is stored into location using the handler
612 * for the last relocation to an address.
613 *
614 * Three layers of indexing:
615 * - Each of the buckets in use
616 * - Groups of relocations in each bucket by location address
617 * - Each relocation entry for a location address
618 */
619 struct used_bucket *bucket_iter;
620 struct used_bucket *bucket_iter_tmp;
621 struct relocation_head *rel_head_iter;
622 struct hlist_node *rel_head_iter_tmp;
623 struct relocation_entry *rel_entry_iter;
624 struct relocation_entry *rel_entry_iter_tmp;
625 int curr_type;
626 void *location;
627 long buffer;
628
629 list_for_each_entry_safe(bucket_iter, bucket_iter_tmp,
630 used_buckets_list, head) {
631 hlist_for_each_entry_safe(rel_head_iter, rel_head_iter_tmp,
632 bucket_iter->bucket, node) {
633 buffer = 0;
634 location = rel_head_iter->location;
635 list_for_each_entry_safe(rel_entry_iter,
636 rel_entry_iter_tmp,
637 &rel_head_iter->rel_entry,
638 head) {
639 curr_type = rel_entry_iter->type;
640 reloc_handlers[curr_type].reloc_handler(
641 me, &buffer, rel_entry_iter->value);
642 kfree(rel_entry_iter);
643 }
644 reloc_handlers[curr_type].accumulate_handler(
645 me, location, buffer);
646 kfree(rel_head_iter);
647 }
648 kfree(bucket_iter);
649 }
650
651 kfree(*relocation_hashtable);
652}
653
654static int add_relocation_to_accumulate(struct module *me, int type,
655 void *location,
656 unsigned int hashtable_bits, Elf_Addr v,
657 struct hlist_head *relocation_hashtable,
658 struct list_head *used_buckets_list)
659{
660 struct relocation_entry *entry;
661 struct relocation_head *rel_head;
662 struct hlist_head *current_head;
663 struct used_bucket *bucket;
664 unsigned long hash;
665
666 entry = kmalloc(sizeof(*entry), GFP_KERNEL);
667
668 if (!entry)
669 return -ENOMEM;
670
671 INIT_LIST_HEAD(&entry->head);
672 entry->type = type;
673 entry->value = v;
674
675 hash = hash_min((uintptr_t)location, hashtable_bits);
676
677 current_head = &relocation_hashtable[hash];
678
679 /*
680 * Search for the relocation_head for the relocations that happen at the
681 * provided location
682 */
683 bool found = false;
684 struct relocation_head *rel_head_iter;
685
686 hlist_for_each_entry(rel_head_iter, current_head, node) {
687 if (rel_head_iter->location == location) {
688 found = true;
689 rel_head = rel_head_iter;
690 break;
691 }
692 }
693
694 /*
695 * If there has not yet been any relocations at the provided location,
696 * create a relocation_head for that location and populate it with this
697 * relocation_entry.
698 */
699 if (!found) {
700 rel_head = kmalloc(sizeof(*rel_head), GFP_KERNEL);
701
702 if (!rel_head) {
703 kfree(entry);
704 return -ENOMEM;
705 }
706
707 INIT_LIST_HEAD(&rel_head->rel_entry);
708 rel_head->location = location;
709 INIT_HLIST_NODE(&rel_head->node);
710 if (!current_head->first) {
711 bucket =
712 kmalloc(sizeof(struct used_bucket), GFP_KERNEL);
713
714 if (!bucket) {
715 kfree(entry);
716 kfree(rel_head);
717 return -ENOMEM;
718 }
719
720 INIT_LIST_HEAD(&bucket->head);
721 bucket->bucket = current_head;
722 list_add(&bucket->head, used_buckets_list);
723 }
724 hlist_add_head(&rel_head->node, current_head);
725 }
726
727 /* Add relocation to head of discovered rel_head */
728 list_add_tail(&entry->head, &rel_head->rel_entry);
729
730 return 0;
731}
732
733static unsigned int
734initialize_relocation_hashtable(unsigned int num_relocations,
735 struct hlist_head **relocation_hashtable)
736{
737 /* Can safely assume that bits is not greater than sizeof(long) */
738 unsigned long hashtable_size = roundup_pow_of_two(num_relocations);
739 /*
740 * When hashtable_size == 1, hashtable_bits == 0.
741 * This is valid because the hashing algorithm returns 0 in this case.
742 */
743 unsigned int hashtable_bits = ilog2(hashtable_size);
744
745 /*
746 * Double size of hashtable if num_relocations * 1.25 is greater than
747 * hashtable_size.
748 */
749 int should_double_size = ((num_relocations + (num_relocations >> 2)) > (hashtable_size));
750
751 hashtable_bits += should_double_size;
752
753 hashtable_size <<= should_double_size;
754
755 *relocation_hashtable = kmalloc_array(hashtable_size,
756 sizeof(**relocation_hashtable),
757 GFP_KERNEL);
758 if (!*relocation_hashtable)
759 return 0;
760
761 __hash_init(*relocation_hashtable, hashtable_size);
762
763 return hashtable_bits;
764}
765
766int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab,
767 unsigned int symindex, unsigned int relsec,
768 struct module *me)
769{
770 Elf_Rela *rel = (void *) sechdrs[relsec].sh_addr;
771 int (*handler)(struct module *me, void *location, Elf_Addr v);
772 Elf_Sym *sym;
773 void *location;
774 unsigned int i, type;
775 unsigned int j_idx = 0;
776 Elf_Addr v;
777 int res;
778 unsigned int num_relocations = sechdrs[relsec].sh_size / sizeof(*rel);
779 struct hlist_head *relocation_hashtable;
780 unsigned int hashtable_bits;
781 LIST_HEAD(used_buckets_list);
782
783 hashtable_bits = initialize_relocation_hashtable(num_relocations,
784 &relocation_hashtable);
785
786 if (!relocation_hashtable)
787 return -ENOMEM;
788
789 pr_debug("Applying relocate section %u to %u\n", relsec,
790 sechdrs[relsec].sh_info);
791
792 for (i = 0; i < num_relocations; i++) {
793 /* This is where to make the change */
794 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
795 + rel[i].r_offset;
796 /* This is the symbol it is referring to */
797 sym = (Elf_Sym *)sechdrs[symindex].sh_addr
798 + ELF_RISCV_R_SYM(rel[i].r_info);
799 if (IS_ERR_VALUE(sym->st_value)) {
800 /* Ignore unresolved weak symbol */
801 if (ELF_ST_BIND(sym->st_info) == STB_WEAK)
802 continue;
803 pr_warn("%s: Unknown symbol %s\n",
804 me->name, strtab + sym->st_name);
805 return -ENOENT;
806 }
807
808 type = ELF_RISCV_R_TYPE(rel[i].r_info);
809
810 if (type < ARRAY_SIZE(reloc_handlers))
811 handler = reloc_handlers[type].reloc_handler;
812 else
813 handler = NULL;
814
815 if (!handler) {
816 pr_err("%s: Unknown relocation type %u\n",
817 me->name, type);
818 return -EINVAL;
819 }
820
821 v = sym->st_value + rel[i].r_addend;
822
823 if (type == R_RISCV_PCREL_LO12_I || type == R_RISCV_PCREL_LO12_S) {
824 unsigned int j = j_idx;
825 bool found = false;
826
827 do {
828 unsigned long hi20_loc =
829 sechdrs[sechdrs[relsec].sh_info].sh_addr
830 + rel[j].r_offset;
831 u32 hi20_type = ELF_RISCV_R_TYPE(rel[j].r_info);
832
833 /* Find the corresponding HI20 relocation entry */
834 if (hi20_loc == sym->st_value
835 && (hi20_type == R_RISCV_PCREL_HI20
836 || hi20_type == R_RISCV_GOT_HI20)) {
837 s32 hi20, lo12;
838 Elf_Sym *hi20_sym =
839 (Elf_Sym *)sechdrs[symindex].sh_addr
840 + ELF_RISCV_R_SYM(rel[j].r_info);
841 unsigned long hi20_sym_val =
842 hi20_sym->st_value
843 + rel[j].r_addend;
844
845 /* Calculate lo12 */
846 size_t offset = hi20_sym_val - hi20_loc;
847 if (IS_ENABLED(CONFIG_MODULE_SECTIONS)
848 && hi20_type == R_RISCV_GOT_HI20) {
849 offset = module_emit_got_entry(
850 me, hi20_sym_val);
851 offset = offset - hi20_loc;
852 }
853 hi20 = (offset + 0x800) & 0xfffff000;
854 lo12 = offset - hi20;
855 v = lo12;
856 found = true;
857
858 break;
859 }
860
861 j++;
862 if (j > sechdrs[relsec].sh_size / sizeof(*rel))
863 j = 0;
864
865 } while (j_idx != j);
866
867 if (!found) {
868 pr_err(
869 "%s: Can not find HI20 relocation information\n",
870 me->name);
871 return -EINVAL;
872 }
873
874 /* Record the previous j-loop end index */
875 j_idx = j;
876 }
877
878 if (reloc_handlers[type].accumulate_handler)
879 res = add_relocation_to_accumulate(me, type, location,
880 hashtable_bits, v,
881 relocation_hashtable,
882 &used_buckets_list);
883 else
884 res = handler(me, location, v);
885 if (res)
886 return res;
887 }
888
889 process_accumulated_relocations(me, &relocation_hashtable,
890 &used_buckets_list);
891
892 return 0;
893}
894
895int module_finalize(const Elf_Ehdr *hdr,
896 const Elf_Shdr *sechdrs,
897 struct module *me)
898{
899 const Elf_Shdr *s;
900
901 s = find_section(hdr, sechdrs, ".alternative");
902 if (s)
903 apply_module_alternatives((void *)s->sh_addr, s->sh_size);
904
905 return 0;
906}