1 /* 2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) 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 version 2 as 6 * published by the Free Software Foundation. 7 */ 8 9 #include <linux/module.h> 10 #include <linux/moduleloader.h> 11 #include <linux/kernel.h> 12 #include <linux/elf.h> 13 #include <linux/vmalloc.h> 14 #include <linux/slab.h> 15 #include <linux/fs.h> 16 #include <linux/string.h> 17 #include <asm/unwind.h> 18 19 static inline void arc_write_me(unsigned short *addr, unsigned long value) 20 { 21 *addr = (value & 0xffff0000) >> 16; 22 *(addr + 1) = (value & 0xffff); 23 } 24 25 /* 26 * This gets called before relocation loop in generic loader 27 * Make a note of the section index of unwinding section 28 */ 29 int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 30 char *secstr, struct module *mod) 31 { 32 #ifdef CONFIG_ARC_DW2_UNWIND 33 mod->arch.unw_sec_idx = 0; 34 mod->arch.unw_info = NULL; 35 #endif 36 mod->arch.secstr = secstr; 37 return 0; 38 } 39 40 void module_arch_cleanup(struct module *mod) 41 { 42 #ifdef CONFIG_ARC_DW2_UNWIND 43 if (mod->arch.unw_info) 44 unwind_remove_table(mod->arch.unw_info, 0); 45 #endif 46 } 47 48 int apply_relocate_add(Elf32_Shdr *sechdrs, 49 const char *strtab, 50 unsigned int symindex, /* sec index for sym tbl */ 51 unsigned int relsec, /* sec index for relo sec */ 52 struct module *module) 53 { 54 int i, n, relo_type; 55 Elf32_Rela *rel_entry = (void *)sechdrs[relsec].sh_addr; 56 Elf32_Sym *sym_entry, *sym_sec; 57 Elf32_Addr relocation, location, tgt_addr; 58 unsigned int tgtsec; 59 60 /* 61 * @relsec has relocations e.g. .rela.init.text 62 * @tgtsec is section to patch e.g. .init.text 63 */ 64 tgtsec = sechdrs[relsec].sh_info; 65 tgt_addr = sechdrs[tgtsec].sh_addr; 66 sym_sec = (Elf32_Sym *) sechdrs[symindex].sh_addr; 67 n = sechdrs[relsec].sh_size / sizeof(*rel_entry); 68 69 pr_debug("\nSection to fixup %s @%x\n", 70 module->arch.secstr + sechdrs[tgtsec].sh_name, tgt_addr); 71 pr_debug("=========================================================\n"); 72 pr_debug("r_off\tr_add\tst_value ADDRESS VALUE\n"); 73 pr_debug("=========================================================\n"); 74 75 /* Loop thru entries in relocation section */ 76 for (i = 0; i < n; i++) { 77 const char *s; 78 79 /* This is where to make the change */ 80 location = tgt_addr + rel_entry[i].r_offset; 81 82 /* This is the symbol it is referring to. Note that all 83 undefined symbols have been resolved. */ 84 sym_entry = sym_sec + ELF32_R_SYM(rel_entry[i].r_info); 85 86 relocation = sym_entry->st_value + rel_entry[i].r_addend; 87 88 if (sym_entry->st_name == 0 && ELF_ST_TYPE (sym_entry->st_info) == STT_SECTION) { 89 s = module->arch.secstr + sechdrs[sym_entry->st_shndx].sh_name; 90 } else { 91 s = strtab + sym_entry->st_name; 92 } 93 94 pr_debug(" %x\t%x\t%x %x %x [%s]\n", 95 rel_entry[i].r_offset, rel_entry[i].r_addend, 96 sym_entry->st_value, location, relocation, s); 97 98 /* This assumes modules are built with -mlong-calls 99 * so any branches/jumps are absolute 32 bit jmps 100 * global data access again is abs 32 bit. 101 * Both of these are handled by same relocation type 102 */ 103 relo_type = ELF32_R_TYPE(rel_entry[i].r_info); 104 105 if (likely(R_ARC_32_ME == relo_type)) /* ME ( S + A ) */ 106 arc_write_me((unsigned short *)location, relocation); 107 else if (R_ARC_32 == relo_type) /* ( S + A ) */ 108 *((Elf32_Addr *) location) = relocation; 109 else if (R_ARC_32_PCREL == relo_type) /* ( S + A ) - PDATA ) */ 110 *((Elf32_Addr *) location) = relocation - location; 111 else 112 goto relo_err; 113 114 } 115 116 #ifdef CONFIG_ARC_DW2_UNWIND 117 if (strcmp(module->arch.secstr+sechdrs[tgtsec].sh_name, ".eh_frame") == 0) 118 module->arch.unw_sec_idx = tgtsec; 119 #endif 120 121 return 0; 122 123 relo_err: 124 pr_err("%s: unknown relocation: %u\n", 125 module->name, ELF32_R_TYPE(rel_entry[i].r_info)); 126 return -ENOEXEC; 127 128 } 129 130 /* Just before lift off: After sections have been relocated, we add the 131 * dwarf section to unwinder table pool 132 * This couldn't be done in module_frob_arch_sections() because 133 * relocations had not been applied by then 134 */ 135 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs, 136 struct module *mod) 137 { 138 #ifdef CONFIG_ARC_DW2_UNWIND 139 void *unw; 140 int unwsec = mod->arch.unw_sec_idx; 141 142 if (unwsec) { 143 unw = unwind_add_table(mod, (void *)sechdrs[unwsec].sh_addr, 144 sechdrs[unwsec].sh_size); 145 mod->arch.unw_info = unw; 146 } 147 #endif 148 return 0; 149 } 150