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 #include <linux/bug.h>
25
26 #if 0
27 #define DEBUGP printk
28 #else
29 #define DEBUGP(fmt...)
30 #endif
31
module_alloc(unsigned long size)32 void *module_alloc(unsigned long size)
33 {
34 if (size == 0)
35 return NULL;
36 return vmalloc_exec(size);
37 }
38
39
40 /* Free memory returned from module_alloc */
module_free(struct module * mod,void * module_region)41 void module_free(struct module *mod, void *module_region)
42 {
43 vfree(module_region);
44 /* FIXME: If module_region == mod->init_region, trim exception
45 table entries. */
46 }
47
48 /* We don't need anything special. */
module_frob_arch_sections(Elf_Ehdr * hdr,Elf_Shdr * sechdrs,char * secstrings,struct module * mod)49 int module_frob_arch_sections(Elf_Ehdr *hdr,
50 Elf_Shdr *sechdrs,
51 char *secstrings,
52 struct module *mod)
53 {
54 return 0;
55 }
56
apply_relocate(Elf32_Shdr * sechdrs,const char * strtab,unsigned int symindex,unsigned int relsec,struct module * me)57 int apply_relocate(Elf32_Shdr *sechdrs,
58 const char *strtab,
59 unsigned int symindex,
60 unsigned int relsec,
61 struct module *me)
62 {
63 unsigned int i;
64 Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
65 Elf32_Sym *sym;
66 uint32_t *location;
67
68 DEBUGP("Applying relocate section %u to %u\n", relsec,
69 sechdrs[relsec].sh_info);
70 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
71 /* This is where to make the change */
72 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
73 + rel[i].r_offset;
74 /* This is the symbol it is referring to. Note that all
75 undefined symbols have been resolved. */
76 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
77 + ELF32_R_SYM(rel[i].r_info);
78
79 switch (ELF32_R_TYPE(rel[i].r_info)) {
80 case R_386_32:
81 /* We add the value into the location given */
82 *location += sym->st_value;
83 break;
84 case R_386_PC32:
85 /* Add the value, subtract its postition */
86 *location += sym->st_value - (uint32_t)location;
87 break;
88 default:
89 printk(KERN_ERR "module %s: Unknown relocation: %u\n",
90 me->name, ELF32_R_TYPE(rel[i].r_info));
91 return -ENOEXEC;
92 }
93 }
94 return 0;
95 }
96
apply_relocate_add(Elf32_Shdr * sechdrs,const char * strtab,unsigned int symindex,unsigned int relsec,struct module * me)97 int apply_relocate_add(Elf32_Shdr *sechdrs,
98 const char *strtab,
99 unsigned int symindex,
100 unsigned int relsec,
101 struct module *me)
102 {
103 printk(KERN_ERR "module %s: ADD RELOCATION unsupported\n",
104 me->name);
105 return -ENOEXEC;
106 }
107
module_finalize(const Elf_Ehdr * hdr,const Elf_Shdr * sechdrs,struct module * me)108 int module_finalize(const Elf_Ehdr *hdr,
109 const Elf_Shdr *sechdrs,
110 struct module *me)
111 {
112 const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
113 *para = NULL;
114 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
115
116 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
117 if (!strcmp(".text", secstrings + s->sh_name))
118 text = s;
119 if (!strcmp(".altinstructions", secstrings + s->sh_name))
120 alt = s;
121 if (!strcmp(".smp_locks", secstrings + s->sh_name))
122 locks= s;
123 if (!strcmp(".parainstructions", secstrings + s->sh_name))
124 para = s;
125 }
126
127 if (alt) {
128 /* patch .altinstructions */
129 void *aseg = (void *)alt->sh_addr;
130 apply_alternatives(aseg, aseg + alt->sh_size);
131 }
132 if (locks && text) {
133 void *lseg = (void *)locks->sh_addr;
134 void *tseg = (void *)text->sh_addr;
135 alternatives_smp_module_add(me, me->name,
136 lseg, lseg + locks->sh_size,
137 tseg, tseg + text->sh_size);
138 }
139
140 if (para) {
141 void *pseg = (void *)para->sh_addr;
142 apply_paravirt(pseg, pseg + para->sh_size);
143 }
144
145 return module_bug_finalize(hdr, sechdrs, me);
146 }
147
module_arch_cleanup(struct module * mod)148 void module_arch_cleanup(struct module *mod)
149 {
150 alternatives_smp_module_del(mod);
151 module_bug_cleanup(mod);
152 }
153