/* * Makes a tree bootable image for IBM Evaluation boards. * Basically, just take a zImage, skip the ELF header, and stuff * a 32 byte header on the front. * * We use htonl, which is a network macro, to make sure we're doing * The Right Thing on an LE machine. It's non-obvious, but it should * work on anything BSD'ish. */ #include <fcntl.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/stat.h> #include <unistd.h> #include <netinet/in.h> #ifdef __sun__ #include <inttypes.h> #else #include <stdint.h> #endif /* This gets tacked on the front of the image. There are also a few * bytes allocated after the _start label used by the boot rom (see * head.S for details). */ typedef struct boot_block { uint32_t bb_magic; /* 0x0052504F */ uint32_t bb_dest; /* Target address of the image */ uint32_t bb_num_512blocks; /* Size, rounded-up, in 512 byte blks */ uint32_t bb_debug_flag; /* Run debugger or image after load */ uint32_t bb_entry_point; /* The image address to start */ uint32_t bb_checksum; /* 32 bit checksum including header */ uint32_t reserved[2]; } boot_block_t; #define IMGBLK 512 char tmpbuf[IMGBLK]; int main(int argc, char *argv[]) { int in_fd, out_fd; int nblks, i; uint cksum, *cp; struct stat st; boot_block_t bt; if (argc < 5) { fprintf(stderr, "usage: %s <zImage-file> <boot-image> <load address> <entry point>\n",argv[0]); exit(1); } if (stat(argv[1], &st) < 0) { perror("stat"); exit(2); } nblks = (st.st_size + IMGBLK) / IMGBLK; bt.bb_magic = htonl(0x0052504F); /* If we have the optional entry point parameter, use it */ bt.bb_dest = htonl(strtoul(argv[3], NULL, 0)); bt.bb_entry_point = htonl(strtoul(argv[4], NULL, 0)); /* We know these from the linker command. * ...and then move it up into memory a little more so the * relocation can happen. */ bt.bb_num_512blocks = htonl(nblks); bt.bb_debug_flag = 0; bt.bb_checksum = 0; /* To be neat and tidy :-). */ bt.reserved[0] = 0; bt.reserved[1] = 0; if ((in_fd = open(argv[1], O_RDONLY)) < 0) { perror("zImage open"); exit(3); } if ((out_fd = open(argv[2], (O_RDWR | O_CREAT | O_TRUNC), 0666)) < 0) { perror("bootfile open"); exit(3); } cksum = 0; cp = (void *)&bt; for (i=0; i<sizeof(bt)/sizeof(uint); i++) cksum += *cp++; /* Assume zImage is an ELF file, and skip the 64K header. */ if (read(in_fd, tmpbuf, IMGBLK) != IMGBLK) { fprintf(stderr, "%s is too small to be an ELF image\n", argv[1]); exit(4); } if ((*(uint *)tmpbuf) != htonl(0x7f454c46)) { fprintf(stderr, "%s is not an ELF image\n", argv[1]); exit(4); } if (lseek(in_fd, (64 * 1024), SEEK_SET) < 0) { fprintf(stderr, "%s failed to seek in ELF image\n", argv[1]); exit(4); } nblks -= (64 * 1024) / IMGBLK; /* And away we go...... */ if (write(out_fd, &bt, sizeof(bt)) != sizeof(bt)) { perror("boot-image write"); exit(5); } while (nblks-- > 0) { if (read(in_fd, tmpbuf, IMGBLK) < 0) { perror("zImage read"); exit(5); } cp = (uint *)tmpbuf; for (i=0; i<sizeof(tmpbuf)/sizeof(uint); i++) cksum += *cp++; if (write(out_fd, tmpbuf, sizeof(tmpbuf)) != sizeof(tmpbuf)) { perror("boot-image write"); exit(5); } } /* rewrite the header with the computed checksum. */ bt.bb_checksum = htonl(cksum); if (lseek(out_fd, 0, SEEK_SET) < 0) { perror("rewrite seek"); exit(1); } if (write(out_fd, &bt, sizeof(bt)) != sizeof(bt)) { perror("boot-image rewrite"); exit(1); } exit(0); }