1 /* Kernel module help for i386.
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
25 #if 0
26 #define DEBUGP printk
27 #else
28 #define DEBUGP(fmt...)
29 #endif
30
31 void *module_alloc(unsigned long size)
32 {
33 if (size == 0)
34 return NULL;
35 return vmalloc_exec(size);
36 }
37
38
39 /* Free memory returned from module_alloc */
40 void module_free(struct module *mod, void *module_region)
41 {
42 vfree(module_region);
43 /* FIXME: If module_region == mod->init_region, trim exception
44 table entries. */
45 }
46
47 /* We don't need anything special. */
48 int module_frob_arch_sections(Elf_Ehdr *hdr,
49 Elf_Shdr *sechdrs,
50 char *secstrings,
51 struct module *mod)
52 {
53 return 0;
54 }
55
56 int apply_relocate(Elf32_Shdr *sechdrs,
57 const char *strtab,
58 unsigned int symindex,
59 unsigned int relsec,
60 struct module *me)
61 {
62 unsigned int i;
63 Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
64 Elf32_Sym *sym;
65 uint32_t *location;
66
67 DEBUGP("Applying relocate section %u to %u\n", relsec,
68 sechdrs[relsec].sh_info);
69 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
70 /* This is where to make the change */
71 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
72 + rel[i].r_offset;
73 /* This is the symbol it is referring to. Note that all
74 undefined symbols have been resolved. */
75 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
76 + ELF32_R_SYM(rel[i].r_info);
77
78 switch (ELF32_R_TYPE(rel[i].r_info)) {
79 case R_386_32:
80 /* We add the value into the location given */
81 *location += sym->st_value;
82 break;
83 case R_386_PC32:
84 /* Add the value, subtract its postition */
85 *location += sym->st_value - (uint32_t)location;
86 break;
87 default:
88 printk(KERN_ERR "module %s: Unknown relocation: %u\n",
89 me->name, ELF32_R_TYPE(rel[i].r_info));
90 return -ENOEXEC;
91 }
92 }
93 return 0;
94 }
95
96 int apply_relocate_add(Elf32_Shdr *sechdrs,
97 const char *strtab,
98 unsigned int symindex,
99 unsigned int relsec,
100 struct module *me)
101 {
102 printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n",
103 me->name);
104 return -ENOEXEC;
105 }
106
107 extern void apply_alternatives(void *start, void *end);
108
109 int module_finalize(const Elf_Ehdr *hdr,
110 const Elf_Shdr *sechdrs,
111 struct module *me)
112 {
113 const Elf_Shdr *s;
114 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
115
116 /* look for .altinstructions to patch */
117 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
118 void *seg;
119 if (strcmp(".altinstructions", secstrings + s->sh_name))
120 continue;
121 seg = (void *)s->sh_addr;
122 apply_alternatives(seg, seg + s->sh_size);
123 }
124 return 0;
125 }
126
127 void module_arch_cleanup(struct module *mod)
128 {
129 }
130
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