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 int i; 34 35 mod->arch.unw_sec_idx = 0; 36 mod->arch.unw_info = NULL; 37 38 for (i = 1; i < hdr->e_shnum; i++) { 39 if (strcmp(secstr+sechdrs[i].sh_name, ".eh_frame") == 0) { 40 mod->arch.unw_sec_idx = i; 41 break; 42 } 43 } 44 #endif 45 return 0; 46 } 47 48 void module_arch_cleanup(struct module *mod) 49 { 50 #ifdef CONFIG_ARC_DW2_UNWIND 51 if (mod->arch.unw_info) 52 unwind_remove_table(mod->arch.unw_info, 0); 53 #endif 54 } 55 56 int apply_relocate_add(Elf32_Shdr *sechdrs, 57 const char *strtab, 58 unsigned int symindex, /* sec index for sym tbl */ 59 unsigned int relsec, /* sec index for relo sec */ 60 struct module *module) 61 { 62 int i, n; 63 Elf32_Rela *rel_entry = (void *)sechdrs[relsec].sh_addr; 64 Elf32_Sym *sym_entry, *sym_sec; 65 Elf32_Addr relocation; 66 Elf32_Addr location; 67 Elf32_Addr sec_to_patch; 68 int relo_type; 69 70 sec_to_patch = sechdrs[sechdrs[relsec].sh_info].sh_addr; 71 sym_sec = (Elf32_Sym *) sechdrs[symindex].sh_addr; 72 n = sechdrs[relsec].sh_size / sizeof(*rel_entry); 73 74 pr_debug("\n========== Module Sym reloc ===========================\n"); 75 pr_debug("Section to fixup %x\n", sec_to_patch); 76 pr_debug("=========================================================\n"); 77 pr_debug("rela->r_off | rela->addend | sym->st_value | ADDR | VALUE\n"); 78 pr_debug("=========================================================\n"); 79 80 /* Loop thru entries in relocation section */ 81 for (i = 0; i < n; i++) { 82 83 /* This is where to make the change */ 84 location = sec_to_patch + rel_entry[i].r_offset; 85 86 /* This is the symbol it is referring to. Note that all 87 undefined symbols have been resolved. */ 88 sym_entry = sym_sec + ELF32_R_SYM(rel_entry[i].r_info); 89 90 relocation = sym_entry->st_value + rel_entry[i].r_addend; 91 92 pr_debug("\t%x\t\t%x\t\t%x %x %x [%s]\n", 93 rel_entry[i].r_offset, rel_entry[i].r_addend, 94 sym_entry->st_value, location, relocation, 95 strtab + sym_entry->st_name); 96 97 /* This assumes modules are built with -mlong-calls 98 * so any branches/jumps are absolute 32 bit jmps 99 * global data access again is abs 32 bit. 100 * Both of these are handled by same relocation type 101 */ 102 relo_type = ELF32_R_TYPE(rel_entry[i].r_info); 103 104 if (likely(R_ARC_32_ME == relo_type)) /* ME ( S + A ) */ 105 arc_write_me((unsigned short *)location, relocation); 106 else if (R_ARC_32 == relo_type) /* ( S + A ) */ 107 *((Elf32_Addr *) location) = relocation; 108 else if (R_ARC_32_PCREL == relo_type) /* ( S + A ) - PDATA ) */ 109 *((Elf32_Addr *) location) = relocation - location; 110 else 111 goto relo_err; 112 113 } 114 return 0; 115 116 relo_err: 117 pr_err("%s: unknown relocation: %u\n", 118 module->name, ELF32_R_TYPE(rel_entry[i].r_info)); 119 return -ENOEXEC; 120 121 } 122 123 /* Just before lift off: After sections have been relocated, we add the 124 * dwarf section to unwinder table pool 125 * This couldn't be done in module_frob_arch_sections() because 126 * relocations had not been applied by then 127 */ 128 int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs, 129 struct module *mod) 130 { 131 #ifdef CONFIG_ARC_DW2_UNWIND 132 void *unw; 133 int unwsec = mod->arch.unw_sec_idx; 134 135 if (unwsec) { 136 unw = unwind_add_table(mod, (void *)sechdrs[unwsec].sh_addr, 137 sechdrs[unwsec].sh_size); 138 mod->arch.unw_info = unw; 139 } 140 #endif 141 return 0; 142 } 143