root/arch/powerpc/boot/mktree.c

DEFINITIONS

1. main

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Makes a tree bootable image for IBM Evaluation boards.
   4  * Basically, just take a zImage, skip the ELF header, and stuff
   5  * a 32 byte header on the front.
   6  *
   7  * We use htonl, which is a network macro, to make sure we're doing
   8  * The Right Thing on an LE machine.  It's non-obvious, but it should
   9  * work on anything BSD'ish.
  10  */
  11 
  12 #include <fcntl.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <sys/stat.h>
  17 #include <unistd.h>
  18 #include <netinet/in.h>
  19 #ifdef __sun__
  20 #include <inttypes.h>
  21 #else
  22 #include <stdint.h>
  23 #endif
  24 
  25 /* This gets tacked on the front of the image.  There are also a few
  26  * bytes allocated after the _start label used by the boot rom (see
  27  * head.S for details).
  28  */
  29 typedef struct boot_block {
  30         uint32_t bb_magic;              /* 0x0052504F */
  31         uint32_t bb_dest;               /* Target address of the image */
  32         uint32_t bb_num_512blocks;      /* Size, rounded-up, in 512 byte blks */
  33         uint32_t bb_debug_flag; /* Run debugger or image after load */
  34         uint32_t bb_entry_point;        /* The image address to start */
  35         uint32_t bb_checksum;   /* 32 bit checksum including header */
  36         uint32_t reserved[2];
  37 } boot_block_t;
  38 
  39 #define IMGBLK  512
  40 unsigned int    tmpbuf[IMGBLK / sizeof(unsigned int)];
  41 
  42 int main(int argc, char *argv[])
  43 {
  44         int     in_fd, out_fd;
  45         int     nblks, i;
  46         unsigned int    cksum, *cp;
  47         struct  stat    st;
  48         boot_block_t    bt;
  49 
  50         if (argc < 5) {
  51                 fprintf(stderr, "usage: %s <zImage-file> <boot-image> <load address> <entry point>\n",argv[0]);
  52                 exit(1);
  53         }
  54 
  55         if (stat(argv[1], &st) < 0) {
  56                 perror("stat");
  57                 exit(2);
  58         }
  59 
  60         nblks = (st.st_size + IMGBLK) / IMGBLK;
  61 
  62         bt.bb_magic = htonl(0x0052504F);
  63 
  64         /* If we have the optional entry point parameter, use it */
  65         bt.bb_dest = htonl(strtoul(argv[3], NULL, 0));
  66         bt.bb_entry_point = htonl(strtoul(argv[4], NULL, 0));
  67 
  68         /* We know these from the linker command.
  69          * ...and then move it up into memory a little more so the
  70          * relocation can happen.
  71          */
  72         bt.bb_num_512blocks = htonl(nblks);
  73         bt.bb_debug_flag = 0;
  74 
  75         bt.bb_checksum = 0;
  76 
  77         /* To be neat and tidy :-).
  78         */
  79         bt.reserved[0] = 0;
  80         bt.reserved[1] = 0;
  81 
  82         if ((in_fd = open(argv[1], O_RDONLY)) < 0) {
  83                 perror("zImage open");
  84                 exit(3);
  85         }
  86 
  87         if ((out_fd = open(argv[2], (O_RDWR | O_CREAT | O_TRUNC), 0666)) < 0) {
  88                 perror("bootfile open");
  89                 exit(3);
  90         }
  91 
  92         cksum = 0;
  93         cp = (void *)&bt;
  94         for (i = 0; i < sizeof(bt) / sizeof(unsigned int); i++)
  95                 cksum += *cp++;
  96 
  97         /* Assume zImage is an ELF file, and skip the 64K header.
  98         */
  99         if (read(in_fd, tmpbuf, sizeof(tmpbuf)) != sizeof(tmpbuf)) {
 100                 fprintf(stderr, "%s is too small to be an ELF image\n",
 101                                 argv[1]);
 102                 exit(4);
 103         }
 104 
 105         if (tmpbuf[0] != htonl(0x7f454c46)) {
 106                 fprintf(stderr, "%s is not an ELF image\n", argv[1]);
 107                 exit(4);
 108         }
 109 
 110         if (lseek(in_fd, (64 * 1024), SEEK_SET) < 0) {
 111                 fprintf(stderr, "%s failed to seek in ELF image\n", argv[1]);
 112                 exit(4);
 113         }
 114 
 115         nblks -= (64 * 1024) / IMGBLK;
 116 
 117         /* And away we go......
 118         */
 119         if (write(out_fd, &bt, sizeof(bt)) != sizeof(bt)) {
 120                 perror("boot-image write");
 121                 exit(5);
 122         }
 123 
 124         while (nblks-- > 0) {
 125                 if (read(in_fd, tmpbuf, sizeof(tmpbuf)) < 0) {
 126                         perror("zImage read");
 127                         exit(5);
 128                 }
 129                 cp = tmpbuf;
 130                 for (i = 0; i < sizeof(tmpbuf) / sizeof(unsigned int); i++)
 131                         cksum += *cp++;
 132                 if (write(out_fd, tmpbuf, sizeof(tmpbuf)) != sizeof(tmpbuf)) {
 133                         perror("boot-image write");
 134                         exit(5);
 135                 }
 136         }
 137 
 138         /* rewrite the header with the computed checksum.
 139         */
 140         bt.bb_checksum = htonl(cksum);
 141         if (lseek(out_fd, 0, SEEK_SET) < 0) {
 142                 perror("rewrite seek");
 143                 exit(1);
 144         }
 145         if (write(out_fd, &bt, sizeof(bt)) != sizeof(bt)) {
 146                 perror("boot-image rewrite");
 147                 exit(1);
 148         }
 149 
 150         exit(0);
 151 }