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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 /* Add the value, subtract its position */
118 *location += sym->st_value - (uint32_t)location;
119 break;
120 default:
121 pr_err("%s: Unknown relocation: %u\n",
122 me->name, ELF32_R_TYPE(rel[i].r_info));
123 return -ENOEXEC;
124 }
125 }
126 return 0;
127}
128#else /*X86_64*/
129static int __apply_relocate_add(Elf64_Shdr *sechdrs,
130 const char *strtab,
131 unsigned int symindex,
132 unsigned int relsec,
133 struct module *me,
134 void *(*write)(void *dest, const void *src, size_t len))
135{
136 unsigned int i;
137 Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
138 Elf64_Sym *sym;
139 void *loc;
140 u64 val;
141
142 DEBUGP("Applying relocate section %u to %u\n",
143 relsec, sechdrs[relsec].sh_info);
144 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
145 /* This is where to make the change */
146 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
147 + rel[i].r_offset;
148
149 /* This is the symbol it is referring to. Note that all
150 undefined symbols have been resolved. */
151 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
152 + ELF64_R_SYM(rel[i].r_info);
153
154 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
155 (int)ELF64_R_TYPE(rel[i].r_info),
156 sym->st_value, rel[i].r_addend, (u64)loc);
157
158 val = sym->st_value + rel[i].r_addend;
159
160 switch (ELF64_R_TYPE(rel[i].r_info)) {
161 case R_X86_64_NONE:
162 break;
163 case R_X86_64_64:
164 if (*(u64 *)loc != 0)
165 goto invalid_relocation;
166 write(loc, &val, 8);
167 break;
168 case R_X86_64_32:
169 if (*(u32 *)loc != 0)
170 goto invalid_relocation;
171 write(loc, &val, 4);
172 if (val != *(u32 *)loc)
173 goto overflow;
174 break;
175 case R_X86_64_32S:
176 if (*(s32 *)loc != 0)
177 goto invalid_relocation;
178 write(loc, &val, 4);
179 if ((s64)val != *(s32 *)loc)
180 goto overflow;
181 break;
182 case R_X86_64_PC32:
183 case R_X86_64_PLT32:
184 if (*(u32 *)loc != 0)
185 goto invalid_relocation;
186 val -= (u64)loc;
187 write(loc, &val, 4);
188#if 0
189 if ((s64)val != *(s32 *)loc)
190 goto overflow;
191#endif
192 break;
193 case R_X86_64_PC64:
194 if (*(u64 *)loc != 0)
195 goto invalid_relocation;
196 val -= (u64)loc;
197 write(loc, &val, 8);
198 break;
199 default:
200 pr_err("%s: Unknown rela relocation: %llu\n",
201 me->name, ELF64_R_TYPE(rel[i].r_info));
202 return -ENOEXEC;
203 }
204 }
205 return 0;
206
207invalid_relocation:
208 pr_err("x86/modules: Skipping invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
209 (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
210 return -ENOEXEC;
211
212overflow:
213 pr_err("overflow in relocation type %d val %Lx\n",
214 (int)ELF64_R_TYPE(rel[i].r_info), val);
215 pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
216 me->name);
217 return -ENOEXEC;
218}
219
220int apply_relocate_add(Elf64_Shdr *sechdrs,
221 const char *strtab,
222 unsigned int symindex,
223 unsigned int relsec,
224 struct module *me)
225{
226 int ret;
227 bool early = me->state == MODULE_STATE_UNFORMED;
228 void *(*write)(void *, const void *, size_t) = memcpy;
229
230 if (!early) {
231 write = text_poke;
232 mutex_lock(&text_mutex);
233 }
234
235 ret = __apply_relocate_add(sechdrs, strtab, symindex, relsec, me,
236 write);
237
238 if (!early) {
239 text_poke_sync();
240 mutex_unlock(&text_mutex);
241 }
242
243 return ret;
244}
245
246#endif
247
248int module_finalize(const Elf_Ehdr *hdr,
249 const Elf_Shdr *sechdrs,
250 struct module *me)
251{
252 const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
253 *para = NULL, *orc = NULL, *orc_ip = NULL;
254 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
255
256 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
257 if (!strcmp(".text", secstrings + s->sh_name))
258 text = s;
259 if (!strcmp(".altinstructions", secstrings + s->sh_name))
260 alt = s;
261 if (!strcmp(".smp_locks", secstrings + s->sh_name))
262 locks = s;
263 if (!strcmp(".parainstructions", secstrings + s->sh_name))
264 para = s;
265 if (!strcmp(".orc_unwind", secstrings + s->sh_name))
266 orc = s;
267 if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
268 orc_ip = s;
269 }
270
271 if (alt) {
272 /* patch .altinstructions */
273 void *aseg = (void *)alt->sh_addr;
274 apply_alternatives(aseg, aseg + alt->sh_size);
275 }
276 if (locks && text) {
277 void *lseg = (void *)locks->sh_addr;
278 void *tseg = (void *)text->sh_addr;
279 alternatives_smp_module_add(me, me->name,
280 lseg, lseg + locks->sh_size,
281 tseg, tseg + text->sh_size);
282 }
283
284 if (para) {
285 void *pseg = (void *)para->sh_addr;
286 apply_paravirt(pseg, pseg + para->sh_size);
287 }
288
289 /* make jump label nops */
290 jump_label_apply_nops(me);
291
292 if (orc && orc_ip)
293 unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
294 (void *)orc->sh_addr, orc->sh_size);
295
296 return 0;
297}
298
299void module_arch_cleanup(struct module *mod)
300{
301 alternatives_smp_module_del(mod);
302}
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#include <linux/moduleloader.h>
19#include <linux/elf.h>
20#include <linux/vmalloc.h>
21#include <linux/fs.h>
22#include <linux/string.h>
23#include <linux/kernel.h>
24#include <linux/bug.h>
25#include <linux/mm.h>
26#include <linux/gfp.h>
27#include <linux/jump_label.h>
28
29#include <asm/system.h>
30#include <asm/page.h>
31#include <asm/pgtable.h>
32
33#if 0
34#define DEBUGP printk
35#else
36#define DEBUGP(fmt...)
37#endif
38
39void *module_alloc(unsigned long size)
40{
41 if (PAGE_ALIGN(size) > MODULES_LEN)
42 return NULL;
43 return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
44 GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC,
45 -1, __builtin_return_address(0));
46}
47
48#ifdef CONFIG_X86_32
49int apply_relocate(Elf32_Shdr *sechdrs,
50 const char *strtab,
51 unsigned int symindex,
52 unsigned int relsec,
53 struct module *me)
54{
55 unsigned int i;
56 Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
57 Elf32_Sym *sym;
58 uint32_t *location;
59
60 DEBUGP("Applying relocate section %u to %u\n", relsec,
61 sechdrs[relsec].sh_info);
62 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
63 /* This is where to make the change */
64 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
65 + rel[i].r_offset;
66 /* This is the symbol it is referring to. Note that all
67 undefined symbols have been resolved. */
68 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
69 + ELF32_R_SYM(rel[i].r_info);
70
71 switch (ELF32_R_TYPE(rel[i].r_info)) {
72 case R_386_32:
73 /* We add the value into the location given */
74 *location += sym->st_value;
75 break;
76 case R_386_PC32:
77 /* Add the value, subtract its postition */
78 *location += sym->st_value - (uint32_t)location;
79 break;
80 default:
81 printk(KERN_ERR "module %s: Unknown relocation: %u\n",
82 me->name, ELF32_R_TYPE(rel[i].r_info));
83 return -ENOEXEC;
84 }
85 }
86 return 0;
87}
88#else /*X86_64*/
89int apply_relocate_add(Elf64_Shdr *sechdrs,
90 const char *strtab,
91 unsigned int symindex,
92 unsigned int relsec,
93 struct module *me)
94{
95 unsigned int i;
96 Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
97 Elf64_Sym *sym;
98 void *loc;
99 u64 val;
100
101 DEBUGP("Applying relocate section %u to %u\n", relsec,
102 sechdrs[relsec].sh_info);
103 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
104 /* This is where to make the change */
105 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
106 + rel[i].r_offset;
107
108 /* This is the symbol it is referring to. Note that all
109 undefined symbols have been resolved. */
110 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
111 + ELF64_R_SYM(rel[i].r_info);
112
113 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
114 (int)ELF64_R_TYPE(rel[i].r_info),
115 sym->st_value, rel[i].r_addend, (u64)loc);
116
117 val = sym->st_value + rel[i].r_addend;
118
119 switch (ELF64_R_TYPE(rel[i].r_info)) {
120 case R_X86_64_NONE:
121 break;
122 case R_X86_64_64:
123 *(u64 *)loc = val;
124 break;
125 case R_X86_64_32:
126 *(u32 *)loc = val;
127 if (val != *(u32 *)loc)
128 goto overflow;
129 break;
130 case R_X86_64_32S:
131 *(s32 *)loc = val;
132 if ((s64)val != *(s32 *)loc)
133 goto overflow;
134 break;
135 case R_X86_64_PC32:
136 val -= (u64)loc;
137 *(u32 *)loc = val;
138#if 0
139 if ((s64)val != *(s32 *)loc)
140 goto overflow;
141#endif
142 break;
143 default:
144 printk(KERN_ERR "module %s: Unknown rela relocation: %llu\n",
145 me->name, ELF64_R_TYPE(rel[i].r_info));
146 return -ENOEXEC;
147 }
148 }
149 return 0;
150
151overflow:
152 printk(KERN_ERR "overflow in relocation type %d val %Lx\n",
153 (int)ELF64_R_TYPE(rel[i].r_info), val);
154 printk(KERN_ERR "`%s' likely not compiled with -mcmodel=kernel\n",
155 me->name);
156 return -ENOEXEC;
157}
158#endif
159
160int module_finalize(const Elf_Ehdr *hdr,
161 const Elf_Shdr *sechdrs,
162 struct module *me)
163{
164 const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
165 *para = NULL;
166 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
167
168 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
169 if (!strcmp(".text", secstrings + s->sh_name))
170 text = s;
171 if (!strcmp(".altinstructions", secstrings + s->sh_name))
172 alt = s;
173 if (!strcmp(".smp_locks", secstrings + s->sh_name))
174 locks = s;
175 if (!strcmp(".parainstructions", secstrings + s->sh_name))
176 para = s;
177 }
178
179 if (alt) {
180 /* patch .altinstructions */
181 void *aseg = (void *)alt->sh_addr;
182 apply_alternatives(aseg, aseg + alt->sh_size);
183 }
184 if (locks && text) {
185 void *lseg = (void *)locks->sh_addr;
186 void *tseg = (void *)text->sh_addr;
187 alternatives_smp_module_add(me, me->name,
188 lseg, lseg + locks->sh_size,
189 tseg, tseg + text->sh_size);
190 }
191
192 if (para) {
193 void *pseg = (void *)para->sh_addr;
194 apply_paravirt(pseg, pseg + para->sh_size);
195 }
196
197 /* make jump label nops */
198 jump_label_apply_nops(me);
199
200 return 0;
201}
202
203void module_arch_cleanup(struct module *mod)
204{
205 alternatives_smp_module_del(mod);
206}