module.c (4254B)
1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) 4 */ 5 6#include <linux/module.h> 7#include <linux/moduleloader.h> 8#include <linux/kernel.h> 9#include <linux/elf.h> 10#include <linux/vmalloc.h> 11#include <linux/slab.h> 12#include <linux/fs.h> 13#include <linux/string.h> 14#include <asm/unwind.h> 15 16static inline void arc_write_me(unsigned short *addr, unsigned long value) 17{ 18 *addr = (value & 0xffff0000) >> 16; 19 *(addr + 1) = (value & 0xffff); 20} 21 22/* 23 * This gets called before relocation loop in generic loader 24 * Make a note of the section index of unwinding section 25 */ 26int module_frob_arch_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, 27 char *secstr, struct module *mod) 28{ 29#ifdef CONFIG_ARC_DW2_UNWIND 30 mod->arch.unw_sec_idx = 0; 31 mod->arch.unw_info = NULL; 32#endif 33 mod->arch.secstr = secstr; 34 return 0; 35} 36 37void module_arch_cleanup(struct module *mod) 38{ 39#ifdef CONFIG_ARC_DW2_UNWIND 40 if (mod->arch.unw_info) 41 unwind_remove_table(mod->arch.unw_info, 0); 42#endif 43} 44 45int apply_relocate_add(Elf32_Shdr *sechdrs, 46 const char *strtab, 47 unsigned int symindex, /* sec index for sym tbl */ 48 unsigned int relsec, /* sec index for relo sec */ 49 struct module *module) 50{ 51 int i, n, relo_type; 52 Elf32_Rela *rel_entry = (void *)sechdrs[relsec].sh_addr; 53 Elf32_Sym *sym_entry, *sym_sec; 54 Elf32_Addr relocation, location, tgt_addr; 55 unsigned int tgtsec; 56 57 /* 58 * @relsec has relocations e.g. .rela.init.text 59 * @tgtsec is section to patch e.g. .init.text 60 */ 61 tgtsec = sechdrs[relsec].sh_info; 62 tgt_addr = sechdrs[tgtsec].sh_addr; 63 sym_sec = (Elf32_Sym *) sechdrs[symindex].sh_addr; 64 n = sechdrs[relsec].sh_size / sizeof(*rel_entry); 65 66 pr_debug("\nSection to fixup %s @%x\n", 67 module->arch.secstr + sechdrs[tgtsec].sh_name, tgt_addr); 68 pr_debug("=========================================================\n"); 69 pr_debug("r_off\tr_add\tst_value ADDRESS VALUE\n"); 70 pr_debug("=========================================================\n"); 71 72 /* Loop thru entries in relocation section */ 73 for (i = 0; i < n; i++) { 74 const char *s; 75 76 /* This is where to make the change */ 77 location = tgt_addr + rel_entry[i].r_offset; 78 79 /* This is the symbol it is referring to. Note that all 80 undefined symbols have been resolved. */ 81 sym_entry = sym_sec + ELF32_R_SYM(rel_entry[i].r_info); 82 83 relocation = sym_entry->st_value + rel_entry[i].r_addend; 84 85 if (sym_entry->st_name == 0 && ELF_ST_TYPE (sym_entry->st_info) == STT_SECTION) { 86 s = module->arch.secstr + sechdrs[sym_entry->st_shndx].sh_name; 87 } else { 88 s = strtab + sym_entry->st_name; 89 } 90 91 pr_debug(" %x\t%x\t%x %x %x [%s]\n", 92 rel_entry[i].r_offset, rel_entry[i].r_addend, 93 sym_entry->st_value, location, relocation, s); 94 95 /* This assumes modules are built with -mlong-calls 96 * so any branches/jumps are absolute 32 bit jmps 97 * global data access again is abs 32 bit. 98 * Both of these are handled by same relocation type 99 */ 100 relo_type = ELF32_R_TYPE(rel_entry[i].r_info); 101 102 if (likely(R_ARC_32_ME == relo_type)) /* ME ( S + A ) */ 103 arc_write_me((unsigned short *)location, relocation); 104 else if (R_ARC_32 == relo_type) /* ( S + A ) */ 105 *((Elf32_Addr *) location) = relocation; 106 else if (R_ARC_32_PCREL == relo_type) /* ( S + A ) - PDATA ) */ 107 *((Elf32_Addr *) location) = relocation - location; 108 else 109 goto relo_err; 110 111 } 112 113#ifdef CONFIG_ARC_DW2_UNWIND 114 if (strcmp(module->arch.secstr+sechdrs[tgtsec].sh_name, ".eh_frame") == 0) 115 module->arch.unw_sec_idx = tgtsec; 116#endif 117 118 return 0; 119 120relo_err: 121 pr_err("%s: unknown relocation: %u\n", 122 module->name, ELF32_R_TYPE(rel_entry[i].r_info)); 123 return -ENOEXEC; 124 125} 126 127/* Just before lift off: After sections have been relocated, we add the 128 * dwarf section to unwinder table pool 129 * This couldn't be done in module_frob_arch_sections() because 130 * relocations had not been applied by then 131 */ 132int module_finalize(const Elf32_Ehdr *hdr, const Elf_Shdr *sechdrs, 133 struct module *mod) 134{ 135#ifdef CONFIG_ARC_DW2_UNWIND 136 void *unw; 137 int unwsec = mod->arch.unw_sec_idx; 138 139 if (unwsec) { 140 unw = unwind_add_table(mod, (void *)sechdrs[unwsec].sh_addr, 141 sechdrs[unwsec].sh_size); 142 mod->arch.unw_info = unw; 143 } 144#endif 145 return 0; 146}