Linas Vepstas | 98fb103 | 2011-10-31 18:40:46 -0500 | [diff] [blame] | 1 | /* |
| 2 | * Kernel module loader for Hexagon |
| 3 | * |
Richard Kuo | e1858b2 | 2012-09-19 16:22:02 -0500 | [diff] [blame] | 4 | * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved. |
Linas Vepstas | 98fb103 | 2011-10-31 18:40:46 -0500 | [diff] [blame] | 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 and |
| 8 | * only version 2 as published by the Free Software Foundation. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program; if not, write to the Free Software |
| 17 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 18 | * 02110-1301, USA. |
| 19 | */ |
| 20 | |
| 21 | #include <asm/module.h> |
| 22 | #include <linux/elf.h> |
| 23 | #include <linux/module.h> |
| 24 | #include <linux/moduleloader.h> |
| 25 | #include <linux/vmalloc.h> |
| 26 | |
| 27 | #if 0 |
| 28 | #define DEBUGP printk |
| 29 | #else |
| 30 | #define DEBUGP(fmt , ...) |
| 31 | #endif |
| 32 | |
| 33 | /* |
| 34 | * module_frob_arch_sections - tweak got/plt sections. |
| 35 | * @hdr - pointer to elf header |
| 36 | * @sechdrs - pointer to elf load section headers |
| 37 | * @secstrings - symbol names |
| 38 | * @mod - pointer to module |
| 39 | */ |
| 40 | int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, |
| 41 | char *secstrings, |
| 42 | struct module *mod) |
| 43 | { |
| 44 | unsigned int i; |
| 45 | int found = 0; |
| 46 | |
| 47 | /* Look for .plt and/or .got.plt and/or .init.plt sections */ |
| 48 | for (i = 0; i < hdr->e_shnum; i++) { |
| 49 | DEBUGP("Section %d is %s\n", i, |
| 50 | secstrings + sechdrs[i].sh_name); |
| 51 | if (strcmp(secstrings + sechdrs[i].sh_name, ".plt") == 0) |
| 52 | found = i+1; |
| 53 | if (strcmp(secstrings + sechdrs[i].sh_name, ".got.plt") == 0) |
| 54 | found = i+1; |
| 55 | if (strcmp(secstrings + sechdrs[i].sh_name, ".rela.plt") == 0) |
| 56 | found = i+1; |
| 57 | } |
| 58 | |
| 59 | /* At this time, we don't support modules comiled with -shared */ |
| 60 | if (found) { |
| 61 | printk(KERN_WARNING |
| 62 | "Module '%s' contains unexpected .plt/.got sections.\n", |
| 63 | mod->name); |
| 64 | /* return -ENOEXEC; */ |
| 65 | } |
| 66 | |
| 67 | return 0; |
| 68 | } |
| 69 | |
| 70 | /* |
| 71 | * apply_relocate_add - perform rela relocations. |
| 72 | * @sechdrs - pointer to section headers |
| 73 | * @strtab - some sort of start address? |
| 74 | * @symindex - symbol index offset or something? |
| 75 | * @relsec - address to relocate to? |
| 76 | * @module - pointer to module |
| 77 | * |
| 78 | * Perform rela relocations. |
| 79 | */ |
| 80 | int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, |
| 81 | unsigned int symindex, unsigned int relsec, |
| 82 | struct module *module) |
| 83 | { |
| 84 | unsigned int i; |
| 85 | Elf32_Sym *sym; |
| 86 | uint32_t *location; |
| 87 | uint32_t value; |
| 88 | unsigned int nrelocs = sechdrs[relsec].sh_size / sizeof(Elf32_Rela); |
| 89 | Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr; |
| 90 | Elf32_Word sym_info = sechdrs[relsec].sh_info; |
| 91 | Elf32_Sym *sym_base = (Elf32_Sym *) sechdrs[symindex].sh_addr; |
| 92 | void *loc_base = (void *) sechdrs[sym_info].sh_addr; |
| 93 | |
| 94 | DEBUGP("Applying relocations in section %u to section %u base=%p\n", |
| 95 | relsec, sym_info, loc_base); |
| 96 | |
| 97 | for (i = 0; i < nrelocs; i++) { |
| 98 | |
| 99 | /* Symbol to relocate */ |
| 100 | sym = sym_base + ELF32_R_SYM(rela[i].r_info); |
| 101 | |
| 102 | /* Where to make the change */ |
| 103 | location = loc_base + rela[i].r_offset; |
| 104 | |
| 105 | /* `Everything is relative'. */ |
| 106 | value = sym->st_value + rela[i].r_addend; |
| 107 | |
| 108 | DEBUGP("%d: value=%08x loc=%p reloc=%d symbol=%s\n", |
| 109 | i, value, location, ELF32_R_TYPE(rela[i].r_info), |
| 110 | sym->st_name ? |
| 111 | &strtab[sym->st_name] : "(anonymous)"); |
| 112 | |
| 113 | switch (ELF32_R_TYPE(rela[i].r_info)) { |
| 114 | case R_HEXAGON_B22_PCREL: { |
| 115 | int dist = (int)(value - (uint32_t)location); |
| 116 | if ((dist < -0x00800000) || |
| 117 | (dist >= 0x00800000)) { |
| 118 | printk(KERN_ERR |
| 119 | "%s: %s: %08x=%08x-%08x %s\n", |
| 120 | module->name, |
| 121 | "R_HEXAGON_B22_PCREL reloc out of range", |
| 122 | dist, value, (uint32_t)location, |
| 123 | sym->st_name ? |
| 124 | &strtab[sym->st_name] : "(anonymous)"); |
| 125 | return -ENOEXEC; |
| 126 | } |
| 127 | DEBUGP("B22_PCREL contents: %08X.\n", *location); |
| 128 | *location &= ~0x01ff3fff; |
| 129 | *location |= 0x00003fff & dist; |
| 130 | *location |= 0x01ff0000 & (dist<<2); |
| 131 | DEBUGP("Contents after reloc: %08x\n", *location); |
| 132 | break; |
| 133 | } |
| 134 | case R_HEXAGON_HI16: |
| 135 | value = (value>>16) & 0xffff; |
| 136 | /* fallthrough */ |
| 137 | case R_HEXAGON_LO16: |
| 138 | *location &= ~0x00c03fff; |
| 139 | *location |= value & 0x3fff; |
| 140 | *location |= (value & 0xc000) << 8; |
| 141 | break; |
| 142 | case R_HEXAGON_32: |
| 143 | *location = value; |
| 144 | break; |
| 145 | case R_HEXAGON_32_PCREL: |
| 146 | *location = value - (uint32_t)location; |
| 147 | break; |
| 148 | case R_HEXAGON_PLT_B22_PCREL: |
| 149 | case R_HEXAGON_GOTOFF_LO16: |
| 150 | case R_HEXAGON_GOTOFF_HI16: |
| 151 | printk(KERN_ERR "%s: GOT/PLT relocations unsupported\n", |
| 152 | module->name); |
| 153 | return -ENOEXEC; |
| 154 | default: |
| 155 | printk(KERN_ERR "%s: unknown relocation: %u\n", |
| 156 | module->name, |
| 157 | ELF32_R_TYPE(rela[i].r_info)); |
| 158 | return -ENOEXEC; |
| 159 | } |
| 160 | } |
| 161 | return 0; |
| 162 | } |