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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/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}