arch/powerpc/boot/addnote.c

   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 }