linux/arch/powerpc/boot/addnote.c
<<
>>
Prefs
   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 * This program is free software; you can redistribute it and/or
  10 * modify it under the terms of the GNU General Public License
  11 * as published by the Free Software Foundation; either version
  12 * 2 of the License, or (at your option) any later version.
  13 *
  14 * Usage: addnote zImage
  15 */
  16#include <stdio.h>
  17#include <stdlib.h>
  18#include <fcntl.h>
  19#include <unistd.h>
  20#include <string.h>
  21
  22/* CHRP note section */
  23static const char arch[] = "PowerPC";
  24
  25#define N_DESCR 6
  26unsigned int descr[N_DESCR] = {
  27        0xffffffff,             /* real-mode = true */
  28        0x02000000,             /* real-base, i.e. where we expect OF to be */
  29        0xffffffff,             /* real-size */
  30        0xffffffff,             /* virt-base */
  31        0xffffffff,             /* virt-size */
  32        0x4000,                 /* load-base */
  33};
  34
  35/* RPA note section */
  36static const char rpaname[] = "IBM,RPA-Client-Config";
  37
  38/*
  39 * Note: setting ignore_my_client_config *should* mean that OF ignores
  40 * all the other fields, but there is a firmware bug which means that
  41 * it looks at the splpar field at least.  So these values need to be
  42 * reasonable.
  43 */
  44#define N_RPA_DESCR     8
  45unsigned int rpanote[N_RPA_DESCR] = {
  46        0,                      /* lparaffinity */
  47        64,                     /* min_rmo_size */
  48        0,                      /* min_rmo_percent */
  49        40,                     /* max_pft_size */
  50        1,                      /* splpar */
  51        -1,                     /* min_load */
  52        0,                      /* new_mem_def */
  53        1,                      /* ignore_my_client_config */
  54};
  55
  56#define ROUNDUP(len)    (((len) + 3) & ~3)
  57
  58unsigned char buf[512];
  59
  60#define GET_16BE(off)   ((buf[off] << 8) + (buf[(off)+1]))
  61#define GET_32BE(off)   ((GET_16BE(off) << 16) + GET_16BE((off)+2))
  62
  63#define PUT_16BE(off, v)        (buf[off] = ((v) >> 8) & 0xff, \
  64                                 buf[(off) + 1] = (v) & 0xff)
  65#define PUT_32BE(off, v)        (PUT_16BE((off), (v) >> 16), \
  66                                 PUT_16BE((off) + 2, (v)))
  67
  68/* Structure of an ELF file */
  69#define E_IDENT         0       /* ELF header */
  70#define E_PHOFF         28
  71#define E_PHENTSIZE     42
  72#define E_PHNUM         44
  73#define E_HSIZE         52      /* size of ELF header */
  74
  75#define EI_MAGIC        0       /* offsets in E_IDENT area */
  76#define EI_CLASS        4
  77#define EI_DATA         5
  78
  79#define PH_TYPE         0       /* ELF program header */
  80#define PH_OFFSET       4
  81#define PH_FILESZ       16
  82#define PH_HSIZE        32      /* size of program header */
  83
  84#define PT_NOTE         4       /* Program header type = note */
  85
  86#define ELFCLASS32      1
  87#define ELFDATA2MSB     2
  88
  89unsigned char elf_magic[4] = { 0x7f, 'E', 'L', 'F' };
  90
  91int
  92main(int ac, char **av)
  93{
  94        int fd, n, i;
  95        int ph, ps, np;
  96        int nnote, nnote2, ns;
  97
  98        if (ac != 2) {
  99                fprintf(stderr, "Usage: %s elf-file\n", av[0]);
 100                exit(1);
 101        }
 102        fd = open(av[1], O_RDWR);
 103        if (fd < 0) {
 104                perror(av[1]);
 105                exit(1);
 106        }
 107
 108        nnote = 12 + ROUNDUP(strlen(arch) + 1) + sizeof(descr);
 109        nnote2 = 12 + ROUNDUP(strlen(rpaname) + 1) + sizeof(rpanote);
 110
 111        n = read(fd, buf, sizeof(buf));
 112        if (n < 0) {
 113                perror("read");
 114                exit(1);
 115        }
 116
 117        if (n < E_HSIZE || memcmp(&buf[E_IDENT+EI_MAGIC], elf_magic, 4) != 0)
 118                goto notelf;
 119
 120        if (buf[E_IDENT+EI_CLASS] != ELFCLASS32
 121            || buf[E_IDENT+EI_DATA] != ELFDATA2MSB) {
 122                fprintf(stderr, "%s is not a big-endian 32-bit ELF image\n",
 123                        av[1]);
 124                exit(1);
 125        }
 126
 127        ph = GET_32BE(E_PHOFF);
 128        ps = GET_16BE(E_PHENTSIZE);
 129        np = GET_16BE(E_PHNUM);
 130        if (ph < E_HSIZE || ps < PH_HSIZE || np < 1)
 131                goto notelf;
 132        if (ph + (np + 2) * ps + nnote + nnote2 > n)
 133                goto nospace;
 134
 135        for (i = 0; i < np; ++i) {
 136                if (GET_32BE(ph + PH_TYPE) == PT_NOTE) {
 137                        fprintf(stderr, "%s already has a note entry\n",
 138                                av[1]);
 139                        exit(0);
 140                }
 141                ph += ps;
 142        }
 143
 144        /* XXX check that the area we want to use is all zeroes */
 145        for (i = 0; i < 2 * ps + nnote + nnote2; ++i)
 146                if (buf[ph + i] != 0)
 147                        goto nospace;
 148
 149        /* fill in the program header entry */
 150        ns = ph + 2 * ps;
 151        PUT_32BE(ph + PH_TYPE, PT_NOTE);
 152        PUT_32BE(ph + PH_OFFSET, ns);
 153        PUT_32BE(ph + PH_FILESZ, nnote);
 154
 155        /* fill in the note area we point to */
 156        /* XXX we should probably make this a proper section */
 157        PUT_32BE(ns, strlen(arch) + 1);
 158        PUT_32BE(ns + 4, N_DESCR * 4);
 159        PUT_32BE(ns + 8, 0x1275);
 160        strcpy((char *) &buf[ns + 12], arch);
 161        ns += 12 + strlen(arch) + 1;
 162        for (i = 0; i < N_DESCR; ++i, ns += 4)
 163                PUT_32BE(ns, descr[i]);
 164
 165        /* fill in the second program header entry and the RPA note area */
 166        ph += ps;
 167        PUT_32BE(ph + PH_TYPE, PT_NOTE);
 168        PUT_32BE(ph + PH_OFFSET, ns);
 169        PUT_32BE(ph + PH_FILESZ, nnote2);
 170
 171        /* fill in the note area we point to */
 172        PUT_32BE(ns, strlen(rpaname) + 1);
 173        PUT_32BE(ns + 4, sizeof(rpanote));
 174        PUT_32BE(ns + 8, 0x12759999);
 175        strcpy((char *) &buf[ns + 12], rpaname);
 176        ns += 12 + ROUNDUP(strlen(rpaname) + 1);
 177        for (i = 0; i < N_RPA_DESCR; ++i, ns += 4)
 178                PUT_32BE(ns, rpanote[i]);
 179
 180        /* Update the number of program headers */
 181        PUT_16BE(E_PHNUM, np + 2);
 182
 183        /* write back */
 184        lseek(fd, (long) 0, SEEK_SET);
 185        i = write(fd, buf, n);
 186        if (i < 0) {
 187                perror("write");
 188                exit(1);
 189        }
 190        if (i < n) {
 191                fprintf(stderr, "%s: write truncated\n", av[1]);
 192                exit(1);
 193        }
 194
 195        exit(0);
 196
 197 notelf:
 198        fprintf(stderr, "%s does not appear to be an ELF file\n", av[1]);
 199        exit(1);
 200
 201 nospace:
 202        fprintf(stderr, "sorry, I can't find space in %s to put the note\n",
 203                av[1]);
 204        exit(1);
 205}
 206