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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#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/page.h>
30#include <asm/pgtable.h>
31
32#if 0
33#define DEBUGP printk
34#else
35#define DEBUGP(fmt...)
36#endif
37
38void *module_alloc(unsigned long size)
39{
40 if (PAGE_ALIGN(size) > MODULES_LEN)
41 return NULL;
42 return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
43 GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC,
44 -1, __builtin_return_address(0));
45}
46
47#ifdef CONFIG_X86_32
48int apply_relocate(Elf32_Shdr *sechdrs,
49 const char *strtab,
50 unsigned int symindex,
51 unsigned int relsec,
52 struct module *me)
53{
54 unsigned int i;
55 Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
56 Elf32_Sym *sym;
57 uint32_t *location;
58
59 DEBUGP("Applying relocate section %u to %u\n", relsec,
60 sechdrs[relsec].sh_info);
61 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
62 /* This is where to make the change */
63 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
64 + rel[i].r_offset;
65 /* This is the symbol it is referring to. Note that all
66 undefined symbols have been resolved. */
67 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
68 + ELF32_R_SYM(rel[i].r_info);
69
70 switch (ELF32_R_TYPE(rel[i].r_info)) {
71 case R_386_32:
72 /* We add the value into the location given */
73 *location += sym->st_value;
74 break;
75 case R_386_PC32:
76 /* Add the value, subtract its postition */
77 *location += sym->st_value - (uint32_t)location;
78 break;
79 default:
80 printk(KERN_ERR "module %s: Unknown relocation: %u\n",
81 me->name, ELF32_R_TYPE(rel[i].r_info));
82 return -ENOEXEC;
83 }
84 }
85 return 0;
86}
87#else /*X86_64*/
88int apply_relocate_add(Elf64_Shdr *sechdrs,
89 const char *strtab,
90 unsigned int symindex,
91 unsigned int relsec,
92 struct module *me)
93{
94 unsigned int i;
95 Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
96 Elf64_Sym *sym;
97 void *loc;
98 u64 val;
99
100 DEBUGP("Applying relocate section %u to %u\n", relsec,
101 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 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
105 + rel[i].r_offset;
106
107 /* This is the symbol it is referring to. Note that all
108 undefined symbols have been resolved. */
109 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
110 + ELF64_R_SYM(rel[i].r_info);
111
112 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
113 (int)ELF64_R_TYPE(rel[i].r_info),
114 sym->st_value, rel[i].r_addend, (u64)loc);
115
116 val = sym->st_value + rel[i].r_addend;
117
118 switch (ELF64_R_TYPE(rel[i].r_info)) {
119 case R_X86_64_NONE:
120 break;
121 case R_X86_64_64:
122 *(u64 *)loc = val;
123 break;
124 case R_X86_64_32:
125 *(u32 *)loc = val;
126 if (val != *(u32 *)loc)
127 goto overflow;
128 break;
129 case R_X86_64_32S:
130 *(s32 *)loc = val;
131 if ((s64)val != *(s32 *)loc)
132 goto overflow;
133 break;
134 case R_X86_64_PC32:
135 val -= (u64)loc;
136 *(u32 *)loc = val;
137#if 0
138 if ((s64)val != *(s32 *)loc)
139 goto overflow;
140#endif
141 break;
142 default:
143 printk(KERN_ERR "module %s: Unknown rela relocation: %llu\n",
144 me->name, ELF64_R_TYPE(rel[i].r_info));
145 return -ENOEXEC;
146 }
147 }
148 return 0;
149
150overflow:
151 printk(KERN_ERR "overflow in relocation type %d val %Lx\n",
152 (int)ELF64_R_TYPE(rel[i].r_info), val);
153 printk(KERN_ERR "`%s' likely not compiled with -mcmodel=kernel\n",
154 me->name);
155 return -ENOEXEC;
156}
157#endif
158
159int module_finalize(const Elf_Ehdr *hdr,
160 const Elf_Shdr *sechdrs,
161 struct module *me)
162{
163 const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
164 *para = NULL;
165 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
166
167 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
168 if (!strcmp(".text", secstrings + s->sh_name))
169 text = s;
170 if (!strcmp(".altinstructions", secstrings + s->sh_name))
171 alt = s;
172 if (!strcmp(".smp_locks", secstrings + s->sh_name))
173 locks = s;
174 if (!strcmp(".parainstructions", secstrings + s->sh_name))
175 para = s;
176 }
177
178 if (alt) {
179 /* patch .altinstructions */
180 void *aseg = (void *)alt->sh_addr;
181 apply_alternatives(aseg, aseg + alt->sh_size);
182 }
183 if (locks && text) {
184 void *lseg = (void *)locks->sh_addr;
185 void *tseg = (void *)text->sh_addr;
186 alternatives_smp_module_add(me, me->name,
187 lseg, lseg + locks->sh_size,
188 tseg, tseg + text->sh_size);
189 }
190
191 if (para) {
192 void *pseg = (void *)para->sh_addr;
193 apply_paravirt(pseg, pseg + para->sh_size);
194 }
195
196 /* make jump label nops */
197 jump_label_apply_nops(me);
198
199 return 0;
200}
201
202void module_arch_cleanup(struct module *mod)
203{
204 alternatives_smp_module_del(mod);
205}
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}