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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/system.h>
30#include <asm/page.h>
31#include <asm/pgtable.h>
32
33#if 0
34#define DEBUGP printk
35#else
36#define DEBUGP(fmt...)
37#endif
38
39void *module_alloc(unsigned long size)
40{
41 if (PAGE_ALIGN(size) > MODULES_LEN)
42 return NULL;
43 return __vmalloc_node_range(size, 1, MODULES_VADDR, MODULES_END,
44 GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC,
45 -1, __builtin_return_address(0));
46}
47
48#ifdef CONFIG_X86_32
49int apply_relocate(Elf32_Shdr *sechdrs,
50 const char *strtab,
51 unsigned int symindex,
52 unsigned int relsec,
53 struct module *me)
54{
55 unsigned int i;
56 Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
57 Elf32_Sym *sym;
58 uint32_t *location;
59
60 DEBUGP("Applying relocate section %u to %u\n", relsec,
61 sechdrs[relsec].sh_info);
62 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
63 /* This is where to make the change */
64 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
65 + rel[i].r_offset;
66 /* This is the symbol it is referring to. Note that all
67 undefined symbols have been resolved. */
68 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
69 + ELF32_R_SYM(rel[i].r_info);
70
71 switch (ELF32_R_TYPE(rel[i].r_info)) {
72 case R_386_32:
73 /* We add the value into the location given */
74 *location += sym->st_value;
75 break;
76 case R_386_PC32:
77 /* Add the value, subtract its postition */
78 *location += sym->st_value - (uint32_t)location;
79 break;
80 default:
81 printk(KERN_ERR "module %s: Unknown relocation: %u\n",
82 me->name, ELF32_R_TYPE(rel[i].r_info));
83 return -ENOEXEC;
84 }
85 }
86 return 0;
87}
88#else /*X86_64*/
89int apply_relocate_add(Elf64_Shdr *sechdrs,
90 const char *strtab,
91 unsigned int symindex,
92 unsigned int relsec,
93 struct module *me)
94{
95 unsigned int i;
96 Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
97 Elf64_Sym *sym;
98 void *loc;
99 u64 val;
100
101 DEBUGP("Applying relocate section %u to %u\n", relsec,
102 sechdrs[relsec].sh_info);
103 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
104 /* This is where to make the change */
105 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
106 + rel[i].r_offset;
107
108 /* This is the symbol it is referring to. Note that all
109 undefined symbols have been resolved. */
110 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
111 + ELF64_R_SYM(rel[i].r_info);
112
113 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
114 (int)ELF64_R_TYPE(rel[i].r_info),
115 sym->st_value, rel[i].r_addend, (u64)loc);
116
117 val = sym->st_value + rel[i].r_addend;
118
119 switch (ELF64_R_TYPE(rel[i].r_info)) {
120 case R_X86_64_NONE:
121 break;
122 case R_X86_64_64:
123 *(u64 *)loc = val;
124 break;
125 case R_X86_64_32:
126 *(u32 *)loc = val;
127 if (val != *(u32 *)loc)
128 goto overflow;
129 break;
130 case R_X86_64_32S:
131 *(s32 *)loc = val;
132 if ((s64)val != *(s32 *)loc)
133 goto overflow;
134 break;
135 case R_X86_64_PC32:
136 val -= (u64)loc;
137 *(u32 *)loc = val;
138#if 0
139 if ((s64)val != *(s32 *)loc)
140 goto overflow;
141#endif
142 break;
143 default:
144 printk(KERN_ERR "module %s: Unknown rela relocation: %llu\n",
145 me->name, ELF64_R_TYPE(rel[i].r_info));
146 return -ENOEXEC;
147 }
148 }
149 return 0;
150
151overflow:
152 printk(KERN_ERR "overflow in relocation type %d val %Lx\n",
153 (int)ELF64_R_TYPE(rel[i].r_info), val);
154 printk(KERN_ERR "`%s' likely not compiled with -mcmodel=kernel\n",
155 me->name);
156 return -ENOEXEC;
157}
158#endif
159
160int module_finalize(const Elf_Ehdr *hdr,
161 const Elf_Shdr *sechdrs,
162 struct module *me)
163{
164 const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
165 *para = NULL;
166 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
167
168 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
169 if (!strcmp(".text", secstrings + s->sh_name))
170 text = s;
171 if (!strcmp(".altinstructions", secstrings + s->sh_name))
172 alt = s;
173 if (!strcmp(".smp_locks", secstrings + s->sh_name))
174 locks = s;
175 if (!strcmp(".parainstructions", secstrings + s->sh_name))
176 para = s;
177 }
178
179 if (alt) {
180 /* patch .altinstructions */
181 void *aseg = (void *)alt->sh_addr;
182 apply_alternatives(aseg, aseg + alt->sh_size);
183 }
184 if (locks && text) {
185 void *lseg = (void *)locks->sh_addr;
186 void *tseg = (void *)text->sh_addr;
187 alternatives_smp_module_add(me, me->name,
188 lseg, lseg + locks->sh_size,
189 tseg, tseg + text->sh_size);
190 }
191
192 if (para) {
193 void *pseg = (void *)para->sh_addr;
194 apply_paravirt(pseg, pseg + para->sh_size);
195 }
196
197 /* make jump label nops */
198 jump_label_apply_nops(me);
199
200 return 0;
201}
202
203void module_arch_cleanup(struct module *mod)
204{
205 alternatives_smp_module_del(mod);
206}
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}