xref: /linux/arch/powerpc/boot/mktree.c (revision 498495dba268b20e8eadd7fe93c140c68b6cc9d2)
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 
main(int argc,char * argv[])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 }
152