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