LXR linux/arch/powerpc/boot/mktree.c

   1/*
   2 * Makes a tree bootable image for IBM Evaluation boards.
   3 * Basically, just take a zImage, skip the ELF header, and stuff
   4 * a 32 byte header on the front.
   5 *
   6 * We use htonl, which is a network macro, to make sure we're doing
   7 * The Right Thing on an LE machine.  It's non-obvious, but it should
   8 * work on anything BSD'ish.
   9 */
  10
  11#include <fcntl.h>
  12#include <stdio.h>
  13#include <stdlib.h>
  14#include <string.h>
  15#include <sys/stat.h>
  16#include <unistd.h>
  17#include <netinet/in.h>
  18#ifdef __sun__
  19#include <inttypes.h>
  20#else
  21#include <stdint.h>
  22#endif
  23
  24/* This gets tacked on the front of the image.  There are also a few
  25 * bytes allocated after the _start label used by the boot rom (see
  26 * head.S for details).
  27 */
  28typedef struct boot_block {
  29        uint32_t bb_magic;              /* 0x0052504F */
  30        uint32_t bb_dest;               /* Target address of the image */
  31        uint32_t bb_num_512blocks;      /* Size, rounded-up, in 512 byte blks */
  32        uint32_t bb_debug_flag; /* Run debugger or image after load */
  33        uint32_t bb_entry_point;        /* The image address to start */
  34        uint32_t bb_checksum;   /* 32 bit checksum including header */
  35        uint32_t reserved[2];
  36} boot_block_t;
  37
  38#define IMGBLK  512
  39unsigned int    tmpbuf[IMGBLK / sizeof(unsigned int)];
  40
  41int main(int argc, char *argv[])
  42{
  43        int     in_fd, out_fd;
  44        int     nblks, i;
  45        unsigned int    cksum, *cp;
  46        struct  stat    st;
  47        boot_block_t    bt;
  48
  49        if (argc < 5) {
  50                fprintf(stderr, "usage: %s <zImage-file> <boot-image> <load address> <entry point>\n",argv[0]);
  51                exit(1);
  52        }
  53
  54        if (stat(argv[1], &st) < 0) {
  55                perror("stat");
  56                exit(2);
  57        }
  58
  59        nblks = (st.st_size + IMGBLK) / IMGBLK;
  60
  61        bt.bb_magic = htonl(0x0052504F);
  62
  63        /* If we have the optional entry point parameter, use it */
  64        bt.bb_dest = htonl(strtoul(argv[3], NULL, 0));
  65        bt.bb_entry_point = htonl(strtoul(argv[4], NULL, 0));
  66
  67        /* We know these from the linker command.
  68         * ...and then move it up into memory a little more so the
  69         * relocation can happen.
  70         */
  71        bt.bb_num_512blocks = htonl(nblks);
  72        bt.bb_debug_flag = 0;
  73
  74        bt.bb_checksum = 0;
  75
  76        /* To be neat and tidy :-).
  77        */
  78        bt.reserved[0] = 0;
  79        bt.reserved[1] = 0;
  80
  81        if ((in_fd = open(argv[1], O_RDONLY)) < 0) {
  82                perror("zImage open");
  83                exit(3);
  84        }
  85
  86        if ((out_fd = open(argv[2], (O_RDWR | O_CREAT | O_TRUNC), 0666)) < 0) {
  87                perror("bootfile open");
  88                exit(3);
  89        }
  90
  91        cksum = 0;
  92        cp = (void *)&bt;
  93        for (i = 0; i < sizeof(bt) / sizeof(unsigned int); i++)
  94                cksum += *cp++;
  95
  96        /* Assume zImage is an ELF file, and skip the 64K header.
  97        */
  98        if (read(in_fd, tmpbuf, sizeof(tmpbuf)) != sizeof(tmpbuf)) {
  99                fprintf(stderr, "%s is too small to be an ELF image\n",
 100                                argv[1]);
 101                exit(4);
 102        }
 103
 104        if (tmpbuf[0] != htonl(0x7f454c46)) {
 105                fprintf(stderr, "%s is not an ELF image\n", argv[1]);
 106                exit(4);
 107        }
 108
 109        if (lseek(in_fd, (64 * 1024), SEEK_SET) < 0) {
 110                fprintf(stderr, "%s failed to seek in ELF image\n", argv[1]);
 111                exit(4);
 112        }
 113
 114        nblks -= (64 * 1024) / IMGBLK;
 115
 116        /* And away we go......
 117        */
 118        if (write(out_fd, &bt, sizeof(bt)) != sizeof(bt)) {
 119                perror("boot-image write");
 120                exit(5);
 121        }
 122
 123        while (nblks-- > 0) {
 124                if (read(in_fd, tmpbuf, sizeof(tmpbuf)) < 0) {
 125                        perror("zImage read");
 126                        exit(5);
 127                }
 128                cp = tmpbuf;
 129                for (i = 0; i < sizeof(tmpbuf) / sizeof(unsigned int); i++)
 130                        cksum += *cp++;
 131                if (write(out_fd, tmpbuf, sizeof(tmpbuf)) != sizeof(tmpbuf)) {
 132                        perror("boot-image write");
 133                        exit(5);
 134                }
 135        }
 136
 137        /* rewrite the header with the computed checksum.
 138        */
 139        bt.bb_checksum = htonl(cksum);
 140        if (lseek(out_fd, 0, SEEK_SET) < 0) {
 141                perror("rewrite seek");
 142                exit(1);
 143        }
 144        if (write(out_fd, &bt, sizeof(bt)) != sizeof(bt)) {
 145                perror("boot-image rewrite");
 146                exit(1);
 147        }
 148
 149        exit(0);
 150}
 151