xref: /openbmc/linux/arch/m68k/tools/amiga/dmesg.c (revision f21e49be)
1 /*
2  *  linux/arch/m68k/tools/amiga/dmesg.c -- Retrieve the kernel messages stored
3  *					   in Chip RAM with the kernel command
4  *					   line option `debug=mem'.
5  *
6  *  © Copyright 1996 by Geert Uytterhoeven <geert@linux-m68k.org>
7  *
8  *
9  *  Usage:
10  *
11  *	dmesg
12  *	dmesg <CHIPMEM_END>
13  *
14  *
15  *  This file is subject to the terms and conditions of the GNU General Public
16  *  License.  See the file COPYING in the main directory of the Linux
17  *  distribution for more details.
18  */
19 
20 
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <unistd.h>
24 
25 
26 #define CHIPMEM_START	0x00000000
27 #define CHIPMEM_END	0x00200000	/* overridden by argv[1] */
28 
29 #define SAVEKMSG_MAGIC1	0x53415645	/* 'SAVE' */
30 #define SAVEKMSG_MAGIC2	0x4B4D5347	/* 'KMSG' */
31 
32 struct savekmsg {
33     u_long magic1;	/* SAVEKMSG_MAGIC1 */
34     u_long magic2;	/* SAVEKMSG_MAGIC2 */
35     u_long magicptr;	/* address of magic1 */
36     u_long size;
37     char data[];
38 };
39 
40 
41 int main(int argc, char *argv[])
42 {
43     u_long start = CHIPMEM_START, end = CHIPMEM_END, p;
44     int found = 0;
45     struct savekmsg *m = NULL;
46 
47     if (argc >= 2)
48 	end = strtoul(argv[1], NULL, 0);
49     printf("Searching for SAVEKMSG magic...\n");
50     for (p = start; p <= end-sizeof(struct savekmsg); p += 4) {
51 	m = (struct savekmsg *)p;
52 	if ((m->magic1 == SAVEKMSG_MAGIC1) && (m->magic2 == SAVEKMSG_MAGIC2) &&
53 	    (m->magicptr == p)) {
54 	    found = 1;
55 	    break;
56 	}
57     }
58     if (!found)
59 	printf("Not found\n");
60     else {
61 	printf("Found %ld bytes at 0x%08lx\n", m->size, (u_long)&m->data);
62 	puts(">>>>>>>>>>>>>>>>>>>>");
63 	fflush(stdout);
64 	write(1, &m->data, m->size);
65 	fflush(stdout);
66 	puts("<<<<<<<<<<<<<<<<<<<<");
67     }
68     return(0);
69 }
70