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1/* Kernel module help for x86.
2 Copyright (C) 2001 Rusty Russell.
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17*/
18
19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21#include <linux/moduleloader.h>
22#include <linux/elf.h>
23#include <linux/vmalloc.h>
24#include <linux/fs.h>
25#include <linux/string.h>
26#include <linux/kernel.h>
27#include <linux/kasan.h>
28#include <linux/bug.h>
29#include <linux/mm.h>
30#include <linux/gfp.h>
31#include <linux/jump_label.h>
32#include <linux/random.h>
33
34#include <asm/text-patching.h>
35#include <asm/page.h>
36#include <asm/pgtable.h>
37#include <asm/setup.h>
38#include <asm/unwind.h>
39
40#if 0
41#define DEBUGP(fmt, ...) \
42 printk(KERN_DEBUG fmt, ##__VA_ARGS__)
43#else
44#define DEBUGP(fmt, ...) \
45do { \
46 if (0) \
47 printk(KERN_DEBUG fmt, ##__VA_ARGS__); \
48} while (0)
49#endif
50
51#ifdef CONFIG_RANDOMIZE_BASE
52static unsigned long module_load_offset;
53
54/* Mutex protects the module_load_offset. */
55static DEFINE_MUTEX(module_kaslr_mutex);
56
57static unsigned long int get_module_load_offset(void)
58{
59 if (kaslr_enabled()) {
60 mutex_lock(&module_kaslr_mutex);
61 /*
62 * Calculate the module_load_offset the first time this
63 * code is called. Once calculated it stays the same until
64 * reboot.
65 */
66 if (module_load_offset == 0)
67 module_load_offset =
68 (get_random_int() % 1024 + 1) * PAGE_SIZE;
69 mutex_unlock(&module_kaslr_mutex);
70 }
71 return module_load_offset;
72}
73#else
74static unsigned long int get_module_load_offset(void)
75{
76 return 0;
77}
78#endif
79
80void *module_alloc(unsigned long size)
81{
82 void *p;
83
84 if (PAGE_ALIGN(size) > MODULES_LEN)
85 return NULL;
86
87 p = __vmalloc_node_range(size, MODULE_ALIGN,
88 MODULES_VADDR + get_module_load_offset(),
89 MODULES_END, GFP_KERNEL,
90 PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
91 __builtin_return_address(0));
92 if (p && (kasan_module_alloc(p, size) < 0)) {
93 vfree(p);
94 return NULL;
95 }
96
97 return p;
98}
99
100#ifdef CONFIG_X86_32
101int apply_relocate(Elf32_Shdr *sechdrs,
102 const char *strtab,
103 unsigned int symindex,
104 unsigned int relsec,
105 struct module *me)
106{
107 unsigned int i;
108 Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
109 Elf32_Sym *sym;
110 uint32_t *location;
111
112 DEBUGP("Applying relocate section %u to %u\n",
113 relsec, sechdrs[relsec].sh_info);
114 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
115 /* This is where to make the change */
116 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
117 + rel[i].r_offset;
118 /* This is the symbol it is referring to. Note that all
119 undefined symbols have been resolved. */
120 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
121 + ELF32_R_SYM(rel[i].r_info);
122
123 switch (ELF32_R_TYPE(rel[i].r_info)) {
124 case R_386_32:
125 /* We add the value into the location given */
126 *location += sym->st_value;
127 break;
128 case R_386_PC32:
129 /* Add the value, subtract its position */
130 *location += sym->st_value - (uint32_t)location;
131 break;
132 default:
133 pr_err("%s: Unknown relocation: %u\n",
134 me->name, ELF32_R_TYPE(rel[i].r_info));
135 return -ENOEXEC;
136 }
137 }
138 return 0;
139}
140#else /*X86_64*/
141int apply_relocate_add(Elf64_Shdr *sechdrs,
142 const char *strtab,
143 unsigned int symindex,
144 unsigned int relsec,
145 struct module *me)
146{
147 unsigned int i;
148 Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
149 Elf64_Sym *sym;
150 void *loc;
151 u64 val;
152
153 DEBUGP("Applying relocate section %u to %u\n",
154 relsec, sechdrs[relsec].sh_info);
155 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
156 /* This is where to make the change */
157 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
158 + rel[i].r_offset;
159
160 /* This is the symbol it is referring to. Note that all
161 undefined symbols have been resolved. */
162 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
163 + ELF64_R_SYM(rel[i].r_info);
164
165 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
166 (int)ELF64_R_TYPE(rel[i].r_info),
167 sym->st_value, rel[i].r_addend, (u64)loc);
168
169 val = sym->st_value + rel[i].r_addend;
170
171 switch (ELF64_R_TYPE(rel[i].r_info)) {
172 case R_X86_64_NONE:
173 break;
174 case R_X86_64_64:
175 if (*(u64 *)loc != 0)
176 goto invalid_relocation;
177 *(u64 *)loc = val;
178 break;
179 case R_X86_64_32:
180 if (*(u32 *)loc != 0)
181 goto invalid_relocation;
182 *(u32 *)loc = val;
183 if (val != *(u32 *)loc)
184 goto overflow;
185 break;
186 case R_X86_64_32S:
187 if (*(s32 *)loc != 0)
188 goto invalid_relocation;
189 *(s32 *)loc = val;
190 if ((s64)val != *(s32 *)loc)
191 goto overflow;
192 break;
193 case R_X86_64_PC32:
194 case R_X86_64_PLT32:
195 if (*(u32 *)loc != 0)
196 goto invalid_relocation;
197 val -= (u64)loc;
198 *(u32 *)loc = val;
199#if 0
200 if ((s64)val != *(s32 *)loc)
201 goto overflow;
202#endif
203 break;
204 default:
205 pr_err("%s: Unknown rela relocation: %llu\n",
206 me->name, ELF64_R_TYPE(rel[i].r_info));
207 return -ENOEXEC;
208 }
209 }
210 return 0;
211
212invalid_relocation:
213 pr_err("x86/modules: Skipping invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
214 (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
215 return -ENOEXEC;
216
217overflow:
218 pr_err("overflow in relocation type %d val %Lx\n",
219 (int)ELF64_R_TYPE(rel[i].r_info), val);
220 pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
221 me->name);
222 return -ENOEXEC;
223}
224#endif
225
226int module_finalize(const Elf_Ehdr *hdr,
227 const Elf_Shdr *sechdrs,
228 struct module *me)
229{
230 const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
231 *para = NULL, *orc = NULL, *orc_ip = NULL;
232 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
233
234 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
235 if (!strcmp(".text", secstrings + s->sh_name))
236 text = s;
237 if (!strcmp(".altinstructions", secstrings + s->sh_name))
238 alt = s;
239 if (!strcmp(".smp_locks", secstrings + s->sh_name))
240 locks = s;
241 if (!strcmp(".parainstructions", secstrings + s->sh_name))
242 para = s;
243 if (!strcmp(".orc_unwind", secstrings + s->sh_name))
244 orc = s;
245 if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
246 orc_ip = s;
247 }
248
249 if (alt) {
250 /* patch .altinstructions */
251 void *aseg = (void *)alt->sh_addr;
252 apply_alternatives(aseg, aseg + alt->sh_size);
253 }
254 if (locks && text) {
255 void *lseg = (void *)locks->sh_addr;
256 void *tseg = (void *)text->sh_addr;
257 alternatives_smp_module_add(me, me->name,
258 lseg, lseg + locks->sh_size,
259 tseg, tseg + text->sh_size);
260 }
261
262 if (para) {
263 void *pseg = (void *)para->sh_addr;
264 apply_paravirt(pseg, pseg + para->sh_size);
265 }
266
267 /* make jump label nops */
268 jump_label_apply_nops(me);
269
270 if (orc && orc_ip)
271 unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
272 (void *)orc->sh_addr, orc->sh_size);
273
274 return 0;
275}
276
277void module_arch_cleanup(struct module *mod)
278{
279 alternatives_smp_module_del(mod);
280}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Kernel module help for x86.
3 Copyright (C) 2001 Rusty Russell.
4
5*/
6
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <linux/moduleloader.h>
10#include <linux/elf.h>
11#include <linux/vmalloc.h>
12#include <linux/fs.h>
13#include <linux/string.h>
14#include <linux/kernel.h>
15#include <linux/kasan.h>
16#include <linux/bug.h>
17#include <linux/mm.h>
18#include <linux/gfp.h>
19#include <linux/jump_label.h>
20#include <linux/random.h>
21#include <linux/memory.h>
22
23#include <asm/text-patching.h>
24#include <asm/page.h>
25#include <asm/setup.h>
26#include <asm/unwind.h>
27
28#if 0
29#define DEBUGP(fmt, ...) \
30 printk(KERN_DEBUG fmt, ##__VA_ARGS__)
31#else
32#define DEBUGP(fmt, ...) \
33do { \
34 if (0) \
35 printk(KERN_DEBUG fmt, ##__VA_ARGS__); \
36} while (0)
37#endif
38
39#ifdef CONFIG_RANDOMIZE_BASE
40static unsigned long module_load_offset;
41
42/* Mutex protects the module_load_offset. */
43static DEFINE_MUTEX(module_kaslr_mutex);
44
45static unsigned long int get_module_load_offset(void)
46{
47 if (kaslr_enabled()) {
48 mutex_lock(&module_kaslr_mutex);
49 /*
50 * Calculate the module_load_offset the first time this
51 * code is called. Once calculated it stays the same until
52 * reboot.
53 */
54 if (module_load_offset == 0)
55 module_load_offset =
56 (get_random_int() % 1024 + 1) * PAGE_SIZE;
57 mutex_unlock(&module_kaslr_mutex);
58 }
59 return module_load_offset;
60}
61#else
62static unsigned long int get_module_load_offset(void)
63{
64 return 0;
65}
66#endif
67
68void *module_alloc(unsigned long size)
69{
70 void *p;
71
72 if (PAGE_ALIGN(size) > MODULES_LEN)
73 return NULL;
74
75 p = __vmalloc_node_range(size, MODULE_ALIGN,
76 MODULES_VADDR + get_module_load_offset(),
77 MODULES_END, GFP_KERNEL,
78 PAGE_KERNEL, 0, NUMA_NO_NODE,
79 __builtin_return_address(0));
80 if (p && (kasan_module_alloc(p, size) < 0)) {
81 vfree(p);
82 return NULL;
83 }
84
85 return p;
86}
87
88#ifdef CONFIG_X86_32
89int apply_relocate(Elf32_Shdr *sechdrs,
90 const char *strtab,
91 unsigned int symindex,
92 unsigned int relsec,
93 struct module *me)
94{
95 unsigned int i;
96 Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
97 Elf32_Sym *sym;
98 uint32_t *location;
99
100 DEBUGP("Applying relocate section %u to %u\n",
101 relsec, sechdrs[relsec].sh_info);
102 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
103 /* This is where to make the change */
104 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
105 + rel[i].r_offset;
106 /* This is the symbol it is referring to. Note that all
107 undefined symbols have been resolved. */
108 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
109 + ELF32_R_SYM(rel[i].r_info);
110
111 switch (ELF32_R_TYPE(rel[i].r_info)) {
112 case R_386_32:
113 /* We add the value into the location given */
114 *location += sym->st_value;
115 break;
116 case R_386_PC32:
117 case R_386_PLT32:
118 /* Add the value, subtract its position */
119 *location += sym->st_value - (uint32_t)location;
120 break;
121 default:
122 pr_err("%s: Unknown relocation: %u\n",
123 me->name, ELF32_R_TYPE(rel[i].r_info));
124 return -ENOEXEC;
125 }
126 }
127 return 0;
128}
129#else /*X86_64*/
130static int __apply_relocate_add(Elf64_Shdr *sechdrs,
131 const char *strtab,
132 unsigned int symindex,
133 unsigned int relsec,
134 struct module *me,
135 void *(*write)(void *dest, const void *src, size_t len))
136{
137 unsigned int i;
138 Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
139 Elf64_Sym *sym;
140 void *loc;
141 u64 val;
142
143 DEBUGP("Applying relocate section %u to %u\n",
144 relsec, sechdrs[relsec].sh_info);
145 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
146 /* This is where to make the change */
147 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
148 + rel[i].r_offset;
149
150 /* This is the symbol it is referring to. Note that all
151 undefined symbols have been resolved. */
152 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
153 + ELF64_R_SYM(rel[i].r_info);
154
155 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
156 (int)ELF64_R_TYPE(rel[i].r_info),
157 sym->st_value, rel[i].r_addend, (u64)loc);
158
159 val = sym->st_value + rel[i].r_addend;
160
161 switch (ELF64_R_TYPE(rel[i].r_info)) {
162 case R_X86_64_NONE:
163 break;
164 case R_X86_64_64:
165 if (*(u64 *)loc != 0)
166 goto invalid_relocation;
167 write(loc, &val, 8);
168 break;
169 case R_X86_64_32:
170 if (*(u32 *)loc != 0)
171 goto invalid_relocation;
172 write(loc, &val, 4);
173 if (val != *(u32 *)loc)
174 goto overflow;
175 break;
176 case R_X86_64_32S:
177 if (*(s32 *)loc != 0)
178 goto invalid_relocation;
179 write(loc, &val, 4);
180 if ((s64)val != *(s32 *)loc)
181 goto overflow;
182 break;
183 case R_X86_64_PC32:
184 case R_X86_64_PLT32:
185 if (*(u32 *)loc != 0)
186 goto invalid_relocation;
187 val -= (u64)loc;
188 write(loc, &val, 4);
189#if 0
190 if ((s64)val != *(s32 *)loc)
191 goto overflow;
192#endif
193 break;
194 case R_X86_64_PC64:
195 if (*(u64 *)loc != 0)
196 goto invalid_relocation;
197 val -= (u64)loc;
198 write(loc, &val, 8);
199 break;
200 default:
201 pr_err("%s: Unknown rela relocation: %llu\n",
202 me->name, ELF64_R_TYPE(rel[i].r_info));
203 return -ENOEXEC;
204 }
205 }
206 return 0;
207
208invalid_relocation:
209 pr_err("x86/modules: Skipping invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
210 (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
211 return -ENOEXEC;
212
213overflow:
214 pr_err("overflow in relocation type %d val %Lx\n",
215 (int)ELF64_R_TYPE(rel[i].r_info), val);
216 pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
217 me->name);
218 return -ENOEXEC;
219}
220
221int apply_relocate_add(Elf64_Shdr *sechdrs,
222 const char *strtab,
223 unsigned int symindex,
224 unsigned int relsec,
225 struct module *me)
226{
227 int ret;
228 bool early = me->state == MODULE_STATE_UNFORMED;
229 void *(*write)(void *, const void *, size_t) = memcpy;
230
231 if (!early) {
232 write = text_poke;
233 mutex_lock(&text_mutex);
234 }
235
236 ret = __apply_relocate_add(sechdrs, strtab, symindex, relsec, me,
237 write);
238
239 if (!early) {
240 text_poke_sync();
241 mutex_unlock(&text_mutex);
242 }
243
244 return ret;
245}
246
247#endif
248
249int module_finalize(const Elf_Ehdr *hdr,
250 const Elf_Shdr *sechdrs,
251 struct module *me)
252{
253 const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
254 *para = NULL, *orc = NULL, *orc_ip = NULL;
255 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
256
257 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
258 if (!strcmp(".text", secstrings + s->sh_name))
259 text = s;
260 if (!strcmp(".altinstructions", secstrings + s->sh_name))
261 alt = s;
262 if (!strcmp(".smp_locks", secstrings + s->sh_name))
263 locks = s;
264 if (!strcmp(".parainstructions", secstrings + s->sh_name))
265 para = s;
266 if (!strcmp(".orc_unwind", secstrings + s->sh_name))
267 orc = s;
268 if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
269 orc_ip = s;
270 }
271
272 if (alt) {
273 /* patch .altinstructions */
274 void *aseg = (void *)alt->sh_addr;
275 apply_alternatives(aseg, aseg + alt->sh_size);
276 }
277 if (locks && text) {
278 void *lseg = (void *)locks->sh_addr;
279 void *tseg = (void *)text->sh_addr;
280 alternatives_smp_module_add(me, me->name,
281 lseg, lseg + locks->sh_size,
282 tseg, tseg + text->sh_size);
283 }
284
285 if (para) {
286 void *pseg = (void *)para->sh_addr;
287 apply_paravirt(pseg, pseg + para->sh_size);
288 }
289
290 /* make jump label nops */
291 jump_label_apply_nops(me);
292
293 if (orc && orc_ip)
294 unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
295 (void *)orc->sh_addr, orc->sh_size);
296
297 return 0;
298}
299
300void module_arch_cleanup(struct module *mod)
301{
302 alternatives_smp_module_del(mod);
303}