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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
22#include <asm/text-patching.h>
23#include <asm/page.h>
24#include <asm/pgtable.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*/
129int apply_relocate_add(Elf64_Shdr *sechdrs,
130 const char *strtab,
131 unsigned int symindex,
132 unsigned int relsec,
133 struct module *me)
134{
135 unsigned int i;
136 Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
137 Elf64_Sym *sym;
138 void *loc;
139 u64 val;
140
141 DEBUGP("Applying relocate section %u to %u\n",
142 relsec, sechdrs[relsec].sh_info);
143 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
144 /* This is where to make the change */
145 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
146 + rel[i].r_offset;
147
148 /* This is the symbol it is referring to. Note that all
149 undefined symbols have been resolved. */
150 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
151 + ELF64_R_SYM(rel[i].r_info);
152
153 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
154 (int)ELF64_R_TYPE(rel[i].r_info),
155 sym->st_value, rel[i].r_addend, (u64)loc);
156
157 val = sym->st_value + rel[i].r_addend;
158
159 switch (ELF64_R_TYPE(rel[i].r_info)) {
160 case R_X86_64_NONE:
161 break;
162 case R_X86_64_64:
163 if (*(u64 *)loc != 0)
164 goto invalid_relocation;
165 *(u64 *)loc = val;
166 break;
167 case R_X86_64_32:
168 if (*(u32 *)loc != 0)
169 goto invalid_relocation;
170 *(u32 *)loc = val;
171 if (val != *(u32 *)loc)
172 goto overflow;
173 break;
174 case R_X86_64_32S:
175 if (*(s32 *)loc != 0)
176 goto invalid_relocation;
177 *(s32 *)loc = val;
178 if ((s64)val != *(s32 *)loc)
179 goto overflow;
180 break;
181 case R_X86_64_PC32:
182 case R_X86_64_PLT32:
183 if (*(u32 *)loc != 0)
184 goto invalid_relocation;
185 val -= (u64)loc;
186 *(u32 *)loc = val;
187#if 0
188 if ((s64)val != *(s32 *)loc)
189 goto overflow;
190#endif
191 break;
192 case R_X86_64_PC64:
193 if (*(u64 *)loc != 0)
194 goto invalid_relocation;
195 val -= (u64)loc;
196 *(u64 *)loc = val;
197 break;
198 default:
199 pr_err("%s: Unknown rela relocation: %llu\n",
200 me->name, ELF64_R_TYPE(rel[i].r_info));
201 return -ENOEXEC;
202 }
203 }
204 return 0;
205
206invalid_relocation:
207 pr_err("x86/modules: Skipping invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
208 (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
209 return -ENOEXEC;
210
211overflow:
212 pr_err("overflow in relocation type %d val %Lx\n",
213 (int)ELF64_R_TYPE(rel[i].r_info), val);
214 pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
215 me->name);
216 return -ENOEXEC;
217}
218#endif
219
220int module_finalize(const Elf_Ehdr *hdr,
221 const Elf_Shdr *sechdrs,
222 struct module *me)
223{
224 const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
225 *para = NULL, *orc = NULL, *orc_ip = NULL;
226 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
227
228 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
229 if (!strcmp(".text", secstrings + s->sh_name))
230 text = s;
231 if (!strcmp(".altinstructions", secstrings + s->sh_name))
232 alt = s;
233 if (!strcmp(".smp_locks", secstrings + s->sh_name))
234 locks = s;
235 if (!strcmp(".parainstructions", secstrings + s->sh_name))
236 para = s;
237 if (!strcmp(".orc_unwind", secstrings + s->sh_name))
238 orc = s;
239 if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
240 orc_ip = s;
241 }
242
243 if (alt) {
244 /* patch .altinstructions */
245 void *aseg = (void *)alt->sh_addr;
246 apply_alternatives(aseg, aseg + alt->sh_size);
247 }
248 if (locks && text) {
249 void *lseg = (void *)locks->sh_addr;
250 void *tseg = (void *)text->sh_addr;
251 alternatives_smp_module_add(me, me->name,
252 lseg, lseg + locks->sh_size,
253 tseg, tseg + text->sh_size);
254 }
255
256 if (para) {
257 void *pseg = (void *)para->sh_addr;
258 apply_paravirt(pseg, pseg + para->sh_size);
259 }
260
261 /* make jump label nops */
262 jump_label_apply_nops(me);
263
264 if (orc && orc_ip)
265 unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
266 (void *)orc->sh_addr, orc->sh_size);
267
268 return 0;
269}
270
271void module_arch_cleanup(struct module *mod)
272{
273 alternatives_smp_module_del(mod);
274}
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/bug.h>
28#include <linux/mm.h>
29#include <linux/gfp.h>
30#include <linux/jump_label.h>
31#include <linux/random.h>
32
33#include <asm/page.h>
34#include <asm/pgtable.h>
35
36#if 0
37#define DEBUGP(fmt, ...) \
38 printk(KERN_DEBUG fmt, ##__VA_ARGS__)
39#else
40#define DEBUGP(fmt, ...) \
41do { \
42 if (0) \
43 printk(KERN_DEBUG fmt, ##__VA_ARGS__); \
44} while (0)
45#endif
46
47#ifdef CONFIG_RANDOMIZE_BASE
48static unsigned long module_load_offset;
49static int randomize_modules = 1;
50
51/* Mutex protects the module_load_offset. */
52static DEFINE_MUTEX(module_kaslr_mutex);
53
54static int __init parse_nokaslr(char *p)
55{
56 randomize_modules = 0;
57 return 0;
58}
59early_param("nokaslr", parse_nokaslr);
60
61static unsigned long int get_module_load_offset(void)
62{
63 if (randomize_modules) {
64 mutex_lock(&module_kaslr_mutex);
65 /*
66 * Calculate the module_load_offset the first time this
67 * code is called. Once calculated it stays the same until
68 * reboot.
69 */
70 if (module_load_offset == 0)
71 module_load_offset =
72 (get_random_int() % 1024 + 1) * PAGE_SIZE;
73 mutex_unlock(&module_kaslr_mutex);
74 }
75 return module_load_offset;
76}
77#else
78static unsigned long int get_module_load_offset(void)
79{
80 return 0;
81}
82#endif
83
84void *module_alloc(unsigned long size)
85{
86 if (PAGE_ALIGN(size) > MODULES_LEN)
87 return NULL;
88 return __vmalloc_node_range(size, 1,
89 MODULES_VADDR + get_module_load_offset(),
90 MODULES_END, GFP_KERNEL | __GFP_HIGHMEM,
91 PAGE_KERNEL_EXEC, NUMA_NO_NODE,
92 __builtin_return_address(0));
93}
94
95#ifdef CONFIG_X86_32
96int apply_relocate(Elf32_Shdr *sechdrs,
97 const char *strtab,
98 unsigned int symindex,
99 unsigned int relsec,
100 struct module *me)
101{
102 unsigned int i;
103 Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
104 Elf32_Sym *sym;
105 uint32_t *location;
106
107 DEBUGP("Applying relocate section %u to %u\n",
108 relsec, sechdrs[relsec].sh_info);
109 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
110 /* This is where to make the change */
111 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
112 + rel[i].r_offset;
113 /* This is the symbol it is referring to. Note that all
114 undefined symbols have been resolved. */
115 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
116 + ELF32_R_SYM(rel[i].r_info);
117
118 switch (ELF32_R_TYPE(rel[i].r_info)) {
119 case R_386_32:
120 /* We add the value into the location given */
121 *location += sym->st_value;
122 break;
123 case R_386_PC32:
124 /* Add the value, subtract its position */
125 *location += sym->st_value - (uint32_t)location;
126 break;
127 default:
128 pr_err("%s: Unknown relocation: %u\n",
129 me->name, ELF32_R_TYPE(rel[i].r_info));
130 return -ENOEXEC;
131 }
132 }
133 return 0;
134}
135#else /*X86_64*/
136int apply_relocate_add(Elf64_Shdr *sechdrs,
137 const char *strtab,
138 unsigned int symindex,
139 unsigned int relsec,
140 struct module *me)
141{
142 unsigned int i;
143 Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
144 Elf64_Sym *sym;
145 void *loc;
146 u64 val;
147
148 DEBUGP("Applying relocate section %u to %u\n",
149 relsec, sechdrs[relsec].sh_info);
150 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
151 /* This is where to make the change */
152 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
153 + rel[i].r_offset;
154
155 /* This is the symbol it is referring to. Note that all
156 undefined symbols have been resolved. */
157 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
158 + ELF64_R_SYM(rel[i].r_info);
159
160 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
161 (int)ELF64_R_TYPE(rel[i].r_info),
162 sym->st_value, rel[i].r_addend, (u64)loc);
163
164 val = sym->st_value + rel[i].r_addend;
165
166 switch (ELF64_R_TYPE(rel[i].r_info)) {
167 case R_X86_64_NONE:
168 break;
169 case R_X86_64_64:
170 *(u64 *)loc = val;
171 break;
172 case R_X86_64_32:
173 *(u32 *)loc = val;
174 if (val != *(u32 *)loc)
175 goto overflow;
176 break;
177 case R_X86_64_32S:
178 *(s32 *)loc = val;
179 if ((s64)val != *(s32 *)loc)
180 goto overflow;
181 break;
182 case R_X86_64_PC32:
183 val -= (u64)loc;
184 *(u32 *)loc = val;
185#if 0
186 if ((s64)val != *(s32 *)loc)
187 goto overflow;
188#endif
189 break;
190 default:
191 pr_err("%s: Unknown rela relocation: %llu\n",
192 me->name, ELF64_R_TYPE(rel[i].r_info));
193 return -ENOEXEC;
194 }
195 }
196 return 0;
197
198overflow:
199 pr_err("overflow in relocation type %d val %Lx\n",
200 (int)ELF64_R_TYPE(rel[i].r_info), val);
201 pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
202 me->name);
203 return -ENOEXEC;
204}
205#endif
206
207int module_finalize(const Elf_Ehdr *hdr,
208 const Elf_Shdr *sechdrs,
209 struct module *me)
210{
211 const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
212 *para = NULL;
213 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
214
215 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
216 if (!strcmp(".text", secstrings + s->sh_name))
217 text = s;
218 if (!strcmp(".altinstructions", secstrings + s->sh_name))
219 alt = s;
220 if (!strcmp(".smp_locks", secstrings + s->sh_name))
221 locks = s;
222 if (!strcmp(".parainstructions", secstrings + s->sh_name))
223 para = s;
224 }
225
226 if (alt) {
227 /* patch .altinstructions */
228 void *aseg = (void *)alt->sh_addr;
229 apply_alternatives(aseg, aseg + alt->sh_size);
230 }
231 if (locks && text) {
232 void *lseg = (void *)locks->sh_addr;
233 void *tseg = (void *)text->sh_addr;
234 alternatives_smp_module_add(me, me->name,
235 lseg, lseg + locks->sh_size,
236 tseg, tseg + text->sh_size);
237 }
238
239 if (para) {
240 void *pseg = (void *)para->sh_addr;
241 apply_paravirt(pseg, pseg + para->sh_size);
242 }
243
244 /* make jump label nops */
245 jump_label_apply_nops(me);
246
247 return 0;
248}
249
250void module_arch_cleanup(struct module *mod)
251{
252 alternatives_smp_module_del(mod);
253}