1 /* 2 * Copyright (c) 2017 Oracle and/or its affiliates. All rights reserved. 3 */ 4 5 /* 6 * This file is included up to twice from vdso2c.c. It generates code for 7 * 32-bit and 64-bit vDSOs. We will eventually need both for 64-bit builds, 8 * since 32-bit vDSOs will then be built for 32-bit userspace. 9 */ 10 11 static void BITSFUNC(go)(void *raw_addr, size_t raw_len, 12 void *stripped_addr, size_t stripped_len, 13 FILE *outfile, const char *name) 14 { 15 int found_load = 0; 16 unsigned long load_size = -1; /* Work around bogus warning */ 17 unsigned long mapping_size; 18 int i; 19 unsigned long j; 20 ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr; 21 ELF(Ehdr) *hdr = (ELF(Ehdr) *)raw_addr; 22 ELF(Dyn) *dyn = 0, *dyn_end = 0; 23 INT_BITS syms[NSYMS] = {}; 24 25 ELF(Phdr) *pt = (ELF(Phdr) *)(raw_addr + GET_BE(&hdr->e_phoff)); 26 27 /* Walk the segment table. */ 28 for (i = 0; i < GET_BE(&hdr->e_phnum); i++) { 29 if (GET_BE(&pt[i].p_type) == PT_LOAD) { 30 if (found_load) 31 fail("multiple PT_LOAD segs\n"); 32 33 if (GET_BE(&pt[i].p_offset) != 0 || 34 GET_BE(&pt[i].p_vaddr) != 0) 35 fail("PT_LOAD in wrong place\n"); 36 37 if (GET_BE(&pt[i].p_memsz) != GET_BE(&pt[i].p_filesz)) 38 fail("cannot handle memsz != filesz\n"); 39 40 load_size = GET_BE(&pt[i].p_memsz); 41 found_load = 1; 42 } else if (GET_BE(&pt[i].p_type) == PT_DYNAMIC) { 43 dyn = raw_addr + GET_BE(&pt[i].p_offset); 44 dyn_end = raw_addr + GET_BE(&pt[i].p_offset) + 45 GET_BE(&pt[i].p_memsz); 46 } 47 } 48 if (!found_load) 49 fail("no PT_LOAD seg\n"); 50 51 if (stripped_len < load_size) 52 fail("stripped input is too short\n"); 53 54 /* Walk the dynamic table */ 55 for (i = 0; dyn + i < dyn_end && 56 GET_BE(&dyn[i].d_tag) != DT_NULL; i++) { 57 typeof(dyn[i].d_tag) tag = GET_BE(&dyn[i].d_tag); 58 typeof(dyn[i].d_un.d_val) val = GET_BE(&dyn[i].d_un.d_val); 59 60 if ((tag == DT_RELSZ || tag == DT_RELASZ) && (val != 0)) 61 fail("vdso image contains dynamic relocations\n"); 62 } 63 64 /* Walk the section table */ 65 for (i = 0; i < GET_BE(&hdr->e_shnum); i++) { 66 ELF(Shdr) *sh = raw_addr + GET_BE(&hdr->e_shoff) + 67 GET_BE(&hdr->e_shentsize) * i; 68 if (GET_BE(&sh->sh_type) == SHT_SYMTAB) 69 symtab_hdr = sh; 70 } 71 72 if (!symtab_hdr) 73 fail("no symbol table\n"); 74 75 strtab_hdr = raw_addr + GET_BE(&hdr->e_shoff) + 76 GET_BE(&hdr->e_shentsize) * GET_BE(&symtab_hdr->sh_link); 77 78 /* Walk the symbol table */ 79 for (i = 0; 80 i < GET_BE(&symtab_hdr->sh_size) / GET_BE(&symtab_hdr->sh_entsize); 81 i++) { 82 int k; 83 84 ELF(Sym) *sym = raw_addr + GET_BE(&symtab_hdr->sh_offset) + 85 GET_BE(&symtab_hdr->sh_entsize) * i; 86 const char *name = raw_addr + GET_BE(&strtab_hdr->sh_offset) + 87 GET_BE(&sym->st_name); 88 89 for (k = 0; k < NSYMS; k++) { 90 if (!strcmp(name, required_syms[k].name)) { 91 if (syms[k]) { 92 fail("duplicate symbol %s\n", 93 required_syms[k].name); 94 } 95 96 /* 97 * Careful: we use negative addresses, but 98 * st_value is unsigned, so we rely 99 * on syms[k] being a signed type of the 100 * correct width. 101 */ 102 syms[k] = GET_BE(&sym->st_value); 103 } 104 } 105 } 106 107 /* Validate mapping addresses. */ 108 if (syms[sym_vvar_start] % 8192) 109 fail("vvar_begin must be a multiple of 8192\n"); 110 111 if (!name) { 112 fwrite(stripped_addr, stripped_len, 1, outfile); 113 return; 114 } 115 116 mapping_size = (stripped_len + 8191) / 8192 * 8192; 117 118 fprintf(outfile, "/* AUTOMATICALLY GENERATED -- DO NOT EDIT */\n\n"); 119 fprintf(outfile, "#include <linux/cache.h>\n"); 120 fprintf(outfile, "#include <asm/vdso.h>\n"); 121 fprintf(outfile, "\n"); 122 fprintf(outfile, 123 "static unsigned char raw_data[%lu] __ro_after_init __aligned(8192)= {", 124 mapping_size); 125 for (j = 0; j < stripped_len; j++) { 126 if (j % 10 == 0) 127 fprintf(outfile, "\n\t"); 128 fprintf(outfile, "0x%02X, ", 129 (int)((unsigned char *)stripped_addr)[j]); 130 } 131 fprintf(outfile, "\n};\n\n"); 132 133 fprintf(outfile, "const struct vdso_image %s_builtin = {\n", name); 134 fprintf(outfile, "\t.data = raw_data,\n"); 135 fprintf(outfile, "\t.size = %lu,\n", mapping_size); 136 for (i = 0; i < NSYMS; i++) { 137 if (required_syms[i].export && syms[i]) 138 fprintf(outfile, "\t.sym_%s = %" PRIi64 ",\n", 139 required_syms[i].name, (int64_t)syms[i]); 140 } 141 fprintf(outfile, "};\n"); 142 } 143