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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/* 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}