/* * Program to hack in a PT_NOTE program header entry in an ELF file. * This is needed for OF on RS/6000s to load an image correctly. * Note that OF needs a program header entry for the note, not an * ELF section. * * Copyright 2000 Paul Mackerras. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. * * Usage: addnote zImage */ #include <stdio.h> #include <stdlib.h> #include <fcntl.h> #include <unistd.h> #include <string.h> /* CHRP note section */ char arch[] = "PowerPC"; #define N_DESCR 6 unsigned int descr[N_DESCR] = { 0xffffffff, /* real-mode = true */ 0x02000000, /* real-base, i.e. where we expect OF to be */ 0xffffffff, /* real-size */ 0xffffffff, /* virt-base */ 0xffffffff, /* virt-size */ 0x4000, /* load-base */ }; /* RPA note section */ char rpaname[] = "IBM,RPA-Client-Config"; /* * Note: setting ignore_my_client_config *should* mean that OF ignores * all the other fields, but there is a firmware bug which means that * it looks at the splpar field at least. So these values need to be * reasonable. */ #define N_RPA_DESCR 8 unsigned int rpanote[N_RPA_DESCR] = { 0, /* lparaffinity */ 64, /* min_rmo_size */ 0, /* min_rmo_percent */ 40, /* max_pft_size */ 1, /* splpar */ -1, /* min_load */ 0, /* new_mem_def */ 1, /* ignore_my_client_config */ }; #define ROUNDUP(len) (((len) + 3) & ~3) unsigned char buf[512]; #define GET_16BE(off) ((buf[off] << 8) + (buf[(off)+1])) #define GET_32BE(off) ((GET_16BE(off) << 16) + GET_16BE((off)+2)) #define PUT_16BE(off, v) (buf[off] = ((v) >> 8) & 0xff, \ buf[(off) + 1] = (v) & 0xff) #define PUT_32BE(off, v) (PUT_16BE((off), (v) >> 16), \ PUT_16BE((off) + 2, (v))) /* Structure of an ELF file */ #define E_IDENT 0 /* ELF header */ #define E_PHOFF 28 #define E_PHENTSIZE 42 #define E_PHNUM 44 #define E_HSIZE 52 /* size of ELF header */ #define EI_MAGIC 0 /* offsets in E_IDENT area */ #define EI_CLASS 4 #define EI_DATA 5 #define PH_TYPE 0 /* ELF program header */ #define PH_OFFSET 4 #define PH_FILESZ 16 #define PH_HSIZE 32 /* size of program header */ #define PT_NOTE 4 /* Program header type = note */ #define ELFCLASS32 1 #define ELFDATA2MSB 2 unsigned char elf_magic[4] = { 0x7f, 'E', 'L', 'F' }; int main(int ac, char **av) { int fd, n, i; int ph, ps, np; int nnote, nnote2, ns; if (ac != 2) { fprintf(stderr, "Usage: %s elf-file\n", av[0]); exit(1); } fd = open(av[1], O_RDWR); if (fd < 0) { perror(av[1]); exit(1); } nnote = 12 + ROUNDUP(strlen(arch) + 1) + sizeof(descr); nnote2 = 12 + ROUNDUP(strlen(rpaname) + 1) + sizeof(rpanote); n = read(fd, buf, sizeof(buf)); if (n < 0) { perror("read"); exit(1); } if (n < E_HSIZE || memcmp(&buf[E_IDENT+EI_MAGIC], elf_magic, 4) != 0) goto notelf; if (buf[E_IDENT+EI_CLASS] != ELFCLASS32 || buf[E_IDENT+EI_DATA] != ELFDATA2MSB) { fprintf(stderr, "%s is not a big-endian 32-bit ELF image\n", av[1]); exit(1); } ph = GET_32BE(E_PHOFF); ps = GET_16BE(E_PHENTSIZE); np = GET_16BE(E_PHNUM); if (ph < E_HSIZE || ps < PH_HSIZE || np < 1) goto notelf; if (ph + (np + 2) * ps + nnote + nnote2 > n) goto nospace; for (i = 0; i < np; ++i) { if (GET_32BE(ph + PH_TYPE) == PT_NOTE) { fprintf(stderr, "%s already has a note entry\n", av[1]); exit(0); } ph += ps; } /* XXX check that the area we want to use is all zeroes */ for (i = 0; i < 2 * ps + nnote + nnote2; ++i) if (buf[ph + i] != 0) goto nospace; /* fill in the program header entry */ ns = ph + 2 * ps; PUT_32BE(ph + PH_TYPE, PT_NOTE); PUT_32BE(ph + PH_OFFSET, ns); PUT_32BE(ph + PH_FILESZ, nnote); /* fill in the note area we point to */ /* XXX we should probably make this a proper section */ PUT_32BE(ns, strlen(arch) + 1); PUT_32BE(ns + 4, N_DESCR * 4); PUT_32BE(ns + 8, 0x1275); strcpy((char *) &buf[ns + 12], arch); ns += 12 + strlen(arch) + 1; for (i = 0; i < N_DESCR; ++i, ns += 4) PUT_32BE(ns, descr[i]); /* fill in the second program header entry and the RPA note area */ ph += ps; PUT_32BE(ph + PH_TYPE, PT_NOTE); PUT_32BE(ph + PH_OFFSET, ns); PUT_32BE(ph + PH_FILESZ, nnote2); /* fill in the note area we point to */ PUT_32BE(ns, strlen(rpaname) + 1); PUT_32BE(ns + 4, sizeof(rpanote)); PUT_32BE(ns + 8, 0x12759999); strcpy((char *) &buf[ns + 12], rpaname); ns += 12 + ROUNDUP(strlen(rpaname) + 1); for (i = 0; i < N_RPA_DESCR; ++i, ns += 4) PUT_32BE(ns, rpanote[i]); /* Update the number of program headers */ PUT_16BE(E_PHNUM, np + 2); /* write back */ lseek(fd, (long) 0, SEEK_SET); i = write(fd, buf, n); if (i < 0) { perror("write"); exit(1); } if (i < n) { fprintf(stderr, "%s: write truncated\n", av[1]); exit(1); } exit(0); notelf: fprintf(stderr, "%s does not appear to be an ELF file\n", av[1]); exit(1); nospace: fprintf(stderr, "sorry, I can't find space in %s to put the note\n", av[1]); exit(1); }