cregit-Linux how code gets into the kernel

Release 4.14 arch/powerpc/boot/mktree.c

// SPDX-License-Identifier: GPL-2.0
/*
 * 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

unsigned int	tmpbuf[IMGBLK / sizeof(unsigned int)];


int main(int argc, char *argv[]) { int in_fd, out_fd; int nblks, i; unsigned int 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(unsigned int); i++) cksum += *cp++; /* Assume zImage is an ELF file, and skip the 64K header. */ if (read(in_fd, tmpbuf, sizeof(tmpbuf)) != sizeof(tmpbuf)) { fprintf(stderr, "%s is too small to be an ELF image\n", argv[1]); exit(4); } if (tmpbuf[0] != 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, sizeof(tmpbuf)) < 0) { perror("zImage read"); exit(5); } cp = tmpbuf; for (i = 0; i < sizeof(tmpbuf) / sizeof(unsigned int); 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); }

Contributors

PersonTokensPropCommitsCommitProp
Josh Boyer58093.55%125.00%
Stephen Rothwell152.42%125.00%
David Gibson132.10%125.00%
Timur Tabi121.94%125.00%
Total620100.00%4100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Josh Boyer66092.83%120.00%
Stephen Rothwell253.52%120.00%
David Gibson131.83%120.00%
Timur Tabi121.69%120.00%
Greg Kroah-Hartman10.14%120.00%
Total711100.00%5100.00%
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