1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Program to hack in a PT_NOTE program header entry in an ELF file. 4 * This is needed for OF on RS/6000s to load an image correctly. 5 * Note that OF needs a program header entry for the note, not an 6 * ELF section. 7 * 8 * Copyright 2000 Paul Mackerras. 9 * 10 * Adapted for 64 bit little endian images by Andrew Tauferner. 11 * 12 * Usage: addnote zImage 13 */ 14 #include <stdio.h> 15 #include <stdlib.h> 16 #include <fcntl.h> 17 #include <unistd.h> 18 #include <string.h> 19 20 /* CHRP note section */ 21 static const char arch[] = "PowerPC"; 22 23 #define N_DESCR 6 24 unsigned int descr[N_DESCR] = { 25 0xffffffff, /* real-mode = true */ 26 0x02000000, /* real-base, i.e. where we expect OF to be */ 27 0xffffffff, /* real-size */ 28 0xffffffff, /* virt-base */ 29 0xffffffff, /* virt-size */ 30 0x4000, /* load-base */ 31 }; 32 33 /* RPA note section */ 34 static const char rpaname[] = "IBM,RPA-Client-Config"; 35 36 /* 37 * Note: setting ignore_my_client_config *should* mean that OF ignores 38 * all the other fields, but there is a firmware bug which means that 39 * it looks at the splpar field at least. So these values need to be 40 * reasonable. 41 */ 42 #define N_RPA_DESCR 8 43 unsigned int rpanote[N_RPA_DESCR] = { 44 0, /* lparaffinity */ 45 64, /* min_rmo_size */ 46 0, /* min_rmo_percent */ 47 40, /* max_pft_size */ 48 1, /* splpar */ 49 -1, /* min_load */ 50 0, /* new_mem_def */ 51 1, /* ignore_my_client_config */ 52 }; 53 54 #define ROUNDUP(len) (((len) + 3) & ~3) 55 56 unsigned char buf[1024]; 57 #define ELFDATA2LSB 1 58 #define ELFDATA2MSB 2 59 static int e_data = ELFDATA2MSB; 60 #define ELFCLASS32 1 61 #define ELFCLASS64 2 62 static int e_class = ELFCLASS32; 63 64 #define GET_16BE(off) ((buf[off] << 8) + (buf[(off)+1])) 65 #define GET_32BE(off) ((GET_16BE(off) << 16U) + GET_16BE((off)+2U)) 66 #define GET_64BE(off) ((((unsigned long long)GET_32BE(off)) << 32ULL) + \ 67 ((unsigned long long)GET_32BE((off)+4ULL))) 68 #define PUT_16BE(off, v)(buf[off] = ((v) >> 8) & 0xff, \ 69 buf[(off) + 1] = (v) & 0xff) 70 #define PUT_32BE(off, v)(PUT_16BE((off), (v) >> 16L), PUT_16BE((off) + 2, (v))) 71 #define PUT_64BE(off, v)((PUT_32BE((off), (v) >> 32L), \ 72 PUT_32BE((off) + 4, (v)))) 73 74 #define GET_16LE(off) ((buf[off]) + (buf[(off)+1] << 8)) 75 #define GET_32LE(off) (GET_16LE(off) + (GET_16LE((off)+2U) << 16U)) 76 #define GET_64LE(off) ((unsigned long long)GET_32LE(off) + \ 77 (((unsigned long long)GET_32LE((off)+4ULL)) << 32ULL)) 78 #define PUT_16LE(off, v) (buf[off] = (v) & 0xff, \ 79 buf[(off) + 1] = ((v) >> 8) & 0xff) 80 #define PUT_32LE(off, v) (PUT_16LE((off), (v)), PUT_16LE((off) + 2, (v) >> 16L)) 81 #define PUT_64LE(off, v) (PUT_32LE((off), (v)), PUT_32LE((off) + 4, (v) >> 32L)) 82 83 #define GET_16(off) (e_data == ELFDATA2MSB ? GET_16BE(off) : GET_16LE(off)) 84 #define GET_32(off) (e_data == ELFDATA2MSB ? GET_32BE(off) : GET_32LE(off)) 85 #define GET_64(off) (e_data == ELFDATA2MSB ? GET_64BE(off) : GET_64LE(off)) 86 #define PUT_16(off, v) (e_data == ELFDATA2MSB ? PUT_16BE(off, v) : \ 87 PUT_16LE(off, v)) 88 #define PUT_32(off, v) (e_data == ELFDATA2MSB ? PUT_32BE(off, v) : \ 89 PUT_32LE(off, v)) 90 #define PUT_64(off, v) (e_data == ELFDATA2MSB ? PUT_64BE(off, v) : \ 91 PUT_64LE(off, v)) 92 93 /* Structure of an ELF file */ 94 #define E_IDENT 0 /* ELF header */ 95 #define E_PHOFF (e_class == ELFCLASS32 ? 28 : 32) 96 #define E_PHENTSIZE (e_class == ELFCLASS32 ? 42 : 54) 97 #define E_PHNUM (e_class == ELFCLASS32 ? 44 : 56) 98 #define E_HSIZE (e_class == ELFCLASS32 ? 52 : 64) 99 100 #define EI_MAGIC 0 /* offsets in E_IDENT area */ 101 #define EI_CLASS 4 102 #define EI_DATA 5 103 104 #define PH_TYPE 0 /* ELF program header */ 105 #define PH_OFFSET (e_class == ELFCLASS32 ? 4 : 8) 106 #define PH_FILESZ (e_class == ELFCLASS32 ? 16 : 32) 107 #define PH_HSIZE (e_class == ELFCLASS32 ? 32 : 56) 108 109 #define PT_NOTE 4 /* Program header type = note */ 110 111 112 unsigned char elf_magic[4] = { 0x7f, 'E', 'L', 'F' }; 113 114 int 115 main(int ac, char **av) 116 { 117 int fd, n, i; 118 unsigned long ph, ps, np; 119 long nnote, nnote2, ns; 120 121 if (ac != 2) { 122 fprintf(stderr, "Usage: %s elf-file\n", av[0]); 123 exit(1); 124 } 125 fd = open(av[1], O_RDWR); 126 if (fd < 0) { 127 perror(av[1]); 128 exit(1); 129 } 130 131 nnote = 12 + ROUNDUP(strlen(arch) + 1) + sizeof(descr); 132 nnote2 = 12 + ROUNDUP(strlen(rpaname) + 1) + sizeof(rpanote); 133 134 n = read(fd, buf, sizeof(buf)); 135 if (n < 0) { 136 perror("read"); 137 exit(1); 138 } 139 140 if (memcmp(&buf[E_IDENT+EI_MAGIC], elf_magic, 4) != 0) 141 goto notelf; 142 e_class = buf[E_IDENT+EI_CLASS]; 143 if (e_class != ELFCLASS32 && e_class != ELFCLASS64) 144 goto notelf; 145 e_data = buf[E_IDENT+EI_DATA]; 146 if (e_data != ELFDATA2MSB && e_data != ELFDATA2LSB) 147 goto notelf; 148 if (n < E_HSIZE) 149 goto notelf; 150 151 ph = (e_class == ELFCLASS32 ? GET_32(E_PHOFF) : GET_64(E_PHOFF)); 152 ps = GET_16(E_PHENTSIZE); 153 np = GET_16(E_PHNUM); 154 if (ph < E_HSIZE || ps < PH_HSIZE || np < 1) 155 goto notelf; 156 if (ph + (np + 2) * ps + nnote + nnote2 > n) 157 goto nospace; 158 159 for (i = 0; i < np; ++i) { 160 if (GET_32(ph + PH_TYPE) == PT_NOTE) { 161 fprintf(stderr, "%s already has a note entry\n", 162 av[1]); 163 exit(0); 164 } 165 ph += ps; 166 } 167 168 /* XXX check that the area we want to use is all zeroes */ 169 for (i = 0; i < 2 * ps + nnote + nnote2; ++i) 170 if (buf[ph + i] != 0) 171 goto nospace; 172 173 /* fill in the program header entry */ 174 ns = ph + 2 * ps; 175 PUT_32(ph + PH_TYPE, PT_NOTE); 176 if (e_class == ELFCLASS32) 177 PUT_32(ph + PH_OFFSET, ns); 178 else 179 PUT_64(ph + PH_OFFSET, ns); 180 181 if (e_class == ELFCLASS32) 182 PUT_32(ph + PH_FILESZ, nnote); 183 else 184 PUT_64(ph + PH_FILESZ, nnote); 185 186 /* fill in the note area we point to */ 187 /* XXX we should probably make this a proper section */ 188 PUT_32(ns, strlen(arch) + 1); 189 PUT_32(ns + 4, N_DESCR * 4); 190 PUT_32(ns + 8, 0x1275); 191 strcpy((char *) &buf[ns + 12], arch); 192 ns += 12 + strlen(arch) + 1; 193 for (i = 0; i < N_DESCR; ++i, ns += 4) 194 PUT_32BE(ns, descr[i]); 195 196 /* fill in the second program header entry and the RPA note area */ 197 ph += ps; 198 PUT_32(ph + PH_TYPE, PT_NOTE); 199 if (e_class == ELFCLASS32) 200 PUT_32(ph + PH_OFFSET, ns); 201 else 202 PUT_64(ph + PH_OFFSET, ns); 203 204 if (e_class == ELFCLASS32) 205 PUT_32(ph + PH_FILESZ, nnote); 206 else 207 PUT_64(ph + PH_FILESZ, nnote2); 208 209 /* fill in the note area we point to */ 210 PUT_32(ns, strlen(rpaname) + 1); 211 PUT_32(ns + 4, sizeof(rpanote)); 212 PUT_32(ns + 8, 0x12759999); 213 strcpy((char *) &buf[ns + 12], rpaname); 214 ns += 12 + ROUNDUP(strlen(rpaname) + 1); 215 for (i = 0; i < N_RPA_DESCR; ++i, ns += 4) 216 PUT_32BE(ns, rpanote[i]); 217 218 /* Update the number of program headers */ 219 PUT_16(E_PHNUM, np + 2); 220 221 /* write back */ 222 i = lseek(fd, (long) 0, SEEK_SET); 223 if (i < 0) { 224 perror("lseek"); 225 exit(1); 226 } 227 i = write(fd, buf, n); 228 if (i < 0) { 229 perror("write"); 230 exit(1); 231 } 232 if (i < n) { 233 fprintf(stderr, "%s: write truncated\n", av[1]); 234 exit(1); 235 } 236 237 exit(0); 238 239 notelf: 240 fprintf(stderr, "%s does not appear to be an ELF file\n", av[1]); 241 exit(1); 242 243 nospace: 244 fprintf(stderr, "sorry, I can't find space in %s to put the note\n", 245 av[1]); 246 exit(1); 247 } 248