1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * Copyright (C) 2015 Imagination Technologies 4 * Author: Alex Smith <alex.smith@imgtec.com> 5 */ 6 7 static inline bool FUNC(patch_vdso)(const char *path, void *vdso) 8 { 9 const ELF(Ehdr) *ehdr = vdso; 10 void *shdrs; 11 ELF(Shdr) *shdr; 12 char *shstrtab, *name; 13 uint16_t sh_count, sh_entsize, i; 14 15 shdrs = vdso + FUNC(swap_uint)(ehdr->e_shoff); 16 sh_count = swap_uint16(ehdr->e_shnum); 17 sh_entsize = swap_uint16(ehdr->e_shentsize); 18 19 shdr = shdrs + (sh_entsize * swap_uint16(ehdr->e_shstrndx)); 20 shstrtab = vdso + FUNC(swap_uint)(shdr->sh_offset); 21 22 for (i = 0; i < sh_count; i++) { 23 shdr = shdrs + (i * sh_entsize); 24 name = shstrtab + swap_uint32(shdr->sh_name); 25 26 /* 27 * Ensure there are no relocation sections - ld.so does not 28 * relocate the VDSO so if there are relocations things will 29 * break. 30 */ 31 switch (swap_uint32(shdr->sh_type)) { 32 case SHT_REL: 33 case SHT_RELA: 34 fprintf(stderr, 35 "%s: '%s' contains relocation sections\n", 36 program_name, path); 37 return false; 38 } 39 40 /* Check for existing sections. */ 41 if (strcmp(name, ".MIPS.abiflags") == 0) { 42 fprintf(stderr, 43 "%s: '%s' already contains a '.MIPS.abiflags' section\n", 44 program_name, path); 45 return false; 46 } 47 48 if (strcmp(name, ".mips_abiflags") == 0) { 49 strcpy(name, ".MIPS.abiflags"); 50 shdr->sh_type = swap_uint32(SHT_MIPS_ABIFLAGS); 51 shdr->sh_entsize = shdr->sh_size; 52 } 53 } 54 55 return true; 56 } 57 58 static inline bool FUNC(get_symbols)(const char *path, void *vdso) 59 { 60 const ELF(Ehdr) *ehdr = vdso; 61 void *shdrs, *symtab; 62 ELF(Shdr) *shdr; 63 const ELF(Sym) *sym; 64 char *strtab, *name; 65 uint16_t sh_count, sh_entsize, st_count, st_entsize, i, j; 66 uint64_t offset; 67 uint32_t flags; 68 69 shdrs = vdso + FUNC(swap_uint)(ehdr->e_shoff); 70 sh_count = swap_uint16(ehdr->e_shnum); 71 sh_entsize = swap_uint16(ehdr->e_shentsize); 72 73 for (i = 0; i < sh_count; i++) { 74 shdr = shdrs + (i * sh_entsize); 75 76 if (swap_uint32(shdr->sh_type) == SHT_SYMTAB) 77 break; 78 } 79 80 if (i == sh_count) { 81 fprintf(stderr, "%s: '%s' has no symbol table\n", program_name, 82 path); 83 return false; 84 } 85 86 /* Get flags */ 87 flags = swap_uint32(ehdr->e_flags); 88 if (elf_class == ELFCLASS64) 89 elf_abi = ABI_N64; 90 else if (flags & EF_MIPS_ABI2) 91 elf_abi = ABI_N32; 92 else 93 elf_abi = ABI_O32; 94 95 /* Get symbol table. */ 96 symtab = vdso + FUNC(swap_uint)(shdr->sh_offset); 97 st_entsize = FUNC(swap_uint)(shdr->sh_entsize); 98 st_count = FUNC(swap_uint)(shdr->sh_size) / st_entsize; 99 100 /* Get string table. */ 101 shdr = shdrs + (swap_uint32(shdr->sh_link) * sh_entsize); 102 strtab = vdso + FUNC(swap_uint)(shdr->sh_offset); 103 104 /* Write offsets for symbols needed by the kernel. */ 105 for (i = 0; vdso_symbols[i].name; i++) { 106 if (!(vdso_symbols[i].abis & elf_abi)) 107 continue; 108 109 for (j = 0; j < st_count; j++) { 110 sym = symtab + (j * st_entsize); 111 name = strtab + swap_uint32(sym->st_name); 112 113 if (!strcmp(name, vdso_symbols[i].name)) { 114 offset = FUNC(swap_uint)(sym->st_value); 115 116 fprintf(out_file, 117 "\t.%s = 0x%" PRIx64 ",\n", 118 vdso_symbols[i].offset_name, offset); 119 break; 120 } 121 } 122 123 if (j == st_count) { 124 fprintf(stderr, 125 "%s: '%s' is missing required symbol '%s'\n", 126 program_name, path, vdso_symbols[i].name); 127 return false; 128 } 129 } 130 131 return true; 132 } 133