LXR linux/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 */
  21static const char arch[] = "PowerPC";
  22
  23#define N_DESCR 6
  24unsigned 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 */
  34static 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
  43unsigned 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
  56unsigned char buf[1024];
  57#define ELFDATA2LSB     1
  58#define ELFDATA2MSB     2
  59static int e_data = ELFDATA2MSB;
  60#define ELFCLASS32      1
  61#define ELFCLASS64      2
  62static 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
 112unsigned char elf_magic[4] = { 0x7f, 'E', 'L', 'F' };
 113
 114int
 115main(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