Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | } |