1 /*
2 * Crasher module for kdump testing
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
17 *
18 * Copyright © IBM Corporation 2007
19 *
20 */
21
22 #include <linux/module.h>
23 #include <linux/kernel.h>
24 #include <linux/init.h>
25 #include <linux/proc_fs.h>
26 #include <linux/spinlock.h>
27 #include <asm/uaccess.h>
28 #include <linux/version.h>
29 #include <linux/uaccess.h>
30
31 MODULE_LICENSE("GPL");
32
33 int crasher_init(void);
34 void crasher_exit(void);
35 module_init(crasher_init);
36 module_exit(crasher_exit);
37
38 #define CRASH "crasher" /* name of /proc entry file */
39
40 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,32)
crasher_read(char * buf,char ** start,off_t offset,int len,int * eof,void * data)41 static int crasher_read(char *buf, char **start, off_t offset, int len,
42 int *eof, void *data)
43 #else
44 static ssize_t crasher_read(struct file *file, char __user *buf, size_t len,
45 loff_t *offset)
46 #endif
47 {
48 return (sprintf(buf, "\n"));
49 }
50
51 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,32)
crasher_write(struct file * file,const char * buffer,unsigned long count,void * data)52 static int crasher_write(struct file *file, const char *buffer,
53 unsigned long count, void *data)
54 #else
55 static ssize_t crasher_write(struct file *file, const char __user *buffer,
56 size_t count, loff_t *data)
57 #endif
58 {
59 char value, *a;
60 DEFINE_SPINLOCK(mylock);
61
62 /* grab the first byte the user gave us, ignore the rest */
63 if (copy_from_user(&value, buffer, 1))
64 return -EFAULT;
65
66 switch (value) {
67 case '0': /* panic the system */
68 panic("KDUMP test panic\n");
69 break;
70
71 case '1': /* BUG() test */
72 BUG();
73 break;
74
75 case '2': /* panic_on_oops test */
76 a = 0;
77 a[1] = 'A';
78 break;
79
80 case '3': /* hang w/double spinlock */
81 spin_lock_irq(&mylock);
82 spin_lock_irq(&mylock);
83 break;
84
85 default:
86 printk("crasher: Bad command\n");
87 }
88
89 return count; /* tell the user we read all his data,
90 somtimes white lies are ok */
91 }
92
93 /* create a directory in /proc and a debug file in the new directory */
94
95 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,32)
96 static const struct file_operations crasher_proc_fops = {
97 .owner = THIS_MODULE,
98 .read = crasher_read,
99 .write = crasher_write,
100 };
101 #endif
102
crasher_init(void)103 int crasher_init(void)
104 {
105 struct proc_dir_entry *crasher_proc;
106
107 printk("loaded crasher module\n");
108
109 /* build a crasher file that can be set */
110 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,32)
111 if ((crasher_proc = create_proc_entry(CRASH, 0, NULL)) == NULL) {
112 return -ENOMEM;
113 }
114 crasher_proc->owner = THIS_MODULE
115 crasher_proc->read_proc = crasher_read;
116 crasher_proc->write_proc = crasher_write;
117 #else
118 crasher_proc = proc_create_data(CRASH, 0, NULL,
119 &crasher_proc_fops, NULL);
120 if (!crasher_proc)
121 return -ENOMEM;
122 #endif
123 return 0;
124 }
125
crasher_exit(void)126 void crasher_exit(void)
127 {
128 remove_proc_entry(CRASH, NULL);
129 printk("removed crasher module\n");
130 }
131