arch/powerpc/boot/addnote.c

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