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 21 ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr; 22 ELF(Ehdr) *hdr = (ELF(Ehdr) *)raw_addr; 23 ELF(Dyn) *dyn = 0, *dyn_end = 0; 24 INT_BITS syms[NSYMS] = {}; 25 26 ELF(Phdr) *pt = (ELF(Phdr) *)(raw_addr + GET_BE(&hdr->e_phoff)); 27 28 /* Walk the segment table. */ 29 for (i = 0; i < GET_BE(&hdr->e_phnum); i++) { 30 if (GET_BE(&pt[i].p_type) == PT_LOAD) { 31 if (found_load) 32 fail("multiple PT_LOAD segs\n"); 33 34 if (GET_BE(&pt[i].p_offset) != 0 || 35 GET_BE(&pt[i].p_vaddr) != 0) 36 fail("PT_LOAD in wrong place\n"); 37 38 if (GET_BE(&pt[i].p_memsz) != GET_BE(&pt[i].p_filesz)) 39 fail("cannot handle memsz != filesz\n"); 40 41 load_size = GET_BE(&pt[i].p_memsz); 42 found_load = 1; 43 } else if (GET_BE(&pt[i].p_type) == PT_DYNAMIC) { 44 dyn = raw_addr + GET_BE(&pt[i].p_offset); 45 dyn_end = raw_addr + GET_BE(&pt[i].p_offset) + 46 GET_BE(&pt[i].p_memsz); 47 } 48 } 49 if (!found_load) 50 fail("no PT_LOAD seg\n"); 51 52 if (stripped_len < load_size) 53 fail("stripped input is too short\n"); 54 55 /* Walk the dynamic table */ 56 for (i = 0; dyn + i < dyn_end && 57 GET_BE(&dyn[i].d_tag) != DT_NULL; i++) { 58 typeof(dyn[i].d_tag) tag = GET_BE(&dyn[i].d_tag); 59 typeof(dyn[i].d_un.d_val) val = GET_BE(&dyn[i].d_un.d_val); 60 61 if ((tag == DT_RELSZ || tag == DT_RELASZ) && (val != 0)) 62 fail("vdso image contains dynamic relocations\n"); 63 } 64 65 /* Walk the section table */ 66 for (i = 0; i < GET_BE(&hdr->e_shnum); i++) { 67 ELF(Shdr) *sh = raw_addr + GET_BE(&hdr->e_shoff) + 68 GET_BE(&hdr->e_shentsize) * i; 69 if (GET_BE(&sh->sh_type) == SHT_SYMTAB) 70 symtab_hdr = sh; 71 } 72 73 if (!symtab_hdr) 74 fail("no symbol table\n"); 75 76 strtab_hdr = raw_addr + GET_BE(&hdr->e_shoff) + 77 GET_BE(&hdr->e_shentsize) * GET_BE(&symtab_hdr->sh_link); 78 79 /* Walk the symbol table */ 80 for (i = 0; 81 i < GET_BE(&symtab_hdr->sh_size) / GET_BE(&symtab_hdr->sh_entsize); 82 i++) { 83 int k; 84 85 ELF(Sym) *sym = raw_addr + GET_BE(&symtab_hdr->sh_offset) + 86 GET_BE(&symtab_hdr->sh_entsize) * i; 87 const char *name = raw_addr + GET_BE(&strtab_hdr->sh_offset) + 88 GET_BE(&sym->st_name); 89 90 for (k = 0; k < NSYMS; k++) { 91 if (!strcmp(name, required_syms[k].name)) { 92 if (syms[k]) { 93 fail("duplicate symbol %s\n", 94 required_syms[k].name); 95 } 96 97 /* 98 * Careful: we use negative addresses, but 99 * st_value is unsigned, so we rely 100 * on syms[k] being a signed type of the 101 * correct width. 102 */ 103 syms[k] = GET_BE(&sym->st_value); 104 } 105 } 106 } 107 108 /* Validate mapping addresses. */ 109 if (syms[sym_vvar_start] % 8192) 110 fail("vvar_begin must be a multiple of 8192\n"); 111 112 if (!name) { 113 fwrite(stripped_addr, stripped_len, 1, outfile); 114 return; 115 } 116 117 mapping_size = (stripped_len + 8191) / 8192 * 8192; 118 119 fprintf(outfile, "/* AUTOMATICALLY GENERATED -- DO NOT EDIT */\n\n"); 120 fprintf(outfile, "#include <linux/cache.h>\n"); 121 fprintf(outfile, "#include <asm/vdso.h>\n"); 122 fprintf(outfile, "\n"); 123 fprintf(outfile, 124 "static unsigned char raw_data[%lu] __ro_after_init __aligned(8192)= {", 125 mapping_size); 126 for (j = 0; j < stripped_len; j++) { 127 if (j % 10 == 0) 128 fprintf(outfile, "\n\t"); 129 fprintf(outfile, "0x%02X, ", 130 (int)((unsigned char *)stripped_addr)[j]); 131 } 132 fprintf(outfile, "\n};\n\n"); 133 134 fprintf(outfile, "const struct vdso_image %s_builtin = {\n", name); 135 fprintf(outfile, "\t.data = raw_data,\n"); 136 fprintf(outfile, "\t.size = %lu,\n", mapping_size); 137 for (i = 0; i < NSYMS; i++) { 138 if (required_syms[i].export && syms[i]) 139 fprintf(outfile, "\t.sym_%s = %" PRIi64 ",\n", 140 required_syms[i].name, (int64_t)syms[i]); 141 } 142 fprintf(outfile, "};\n"); 143 } 144