261 lines
6.2 KiB
C
261 lines
6.2 KiB
C
/*
|
|
* Watchdog implementation based on z/VM Watchdog Timer API
|
|
*
|
|
* The user space watchdog daemon can use this driver as
|
|
* /dev/vmwatchdog to have z/VM execute the specified CP
|
|
* command when the timeout expires. The default command is
|
|
* "IPL", which which cause an immediate reboot.
|
|
*/
|
|
#include <linux/init.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/miscdevice.h>
|
|
#include <linux/module.h>
|
|
#include <linux/moduleparam.h>
|
|
#include <linux/watchdog.h>
|
|
|
|
#include <asm/ebcdic.h>
|
|
#include <asm/io.h>
|
|
#include <asm/uaccess.h>
|
|
|
|
#define MAX_CMDLEN 240
|
|
#define MIN_INTERVAL 15
|
|
static char vmwdt_cmd[MAX_CMDLEN] = "IPL";
|
|
static int vmwdt_conceal;
|
|
|
|
static int vmwdt_nowayout = WATCHDOG_NOWAYOUT;
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
|
|
MODULE_DESCRIPTION("z/VM Watchdog Timer");
|
|
module_param_string(cmd, vmwdt_cmd, MAX_CMDLEN, 0644);
|
|
MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers");
|
|
module_param_named(conceal, vmwdt_conceal, bool, 0644);
|
|
MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog "
|
|
" is active");
|
|
module_param_named(nowayout, vmwdt_nowayout, bool, 0);
|
|
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"
|
|
" (default=CONFIG_WATCHDOG_NOWAYOUT)");
|
|
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
|
|
|
|
static unsigned int vmwdt_interval = 60;
|
|
static unsigned long vmwdt_is_open;
|
|
static int vmwdt_expect_close;
|
|
|
|
enum vmwdt_func {
|
|
/* function codes */
|
|
wdt_init = 0,
|
|
wdt_change = 1,
|
|
wdt_cancel = 2,
|
|
/* flags */
|
|
wdt_conceal = 0x80000000,
|
|
};
|
|
|
|
static int __diag288(enum vmwdt_func func, unsigned int timeout,
|
|
char *cmd, size_t len)
|
|
{
|
|
register unsigned long __func asm("2") = func;
|
|
register unsigned long __timeout asm("3") = timeout;
|
|
register unsigned long __cmdp asm("4") = virt_to_phys(cmd);
|
|
register unsigned long __cmdl asm("5") = len;
|
|
int err;
|
|
|
|
err = -EINVAL;
|
|
asm volatile(
|
|
" diag %1,%3,0x288\n"
|
|
"0: la %0,0\n"
|
|
"1:\n"
|
|
EX_TABLE(0b,1b)
|
|
: "+d" (err) : "d"(__func), "d"(__timeout),
|
|
"d"(__cmdp), "d"(__cmdl) : "1", "cc");
|
|
return err;
|
|
}
|
|
|
|
static int vmwdt_keepalive(void)
|
|
{
|
|
/* we allocate new memory every time to avoid having
|
|
* to track the state. static allocation is not an
|
|
* option since that might not be contiguous in real
|
|
* storage in case of a modular build */
|
|
static char *ebc_cmd;
|
|
size_t len;
|
|
int ret;
|
|
unsigned int func;
|
|
|
|
ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
|
|
if (!ebc_cmd)
|
|
return -ENOMEM;
|
|
|
|
len = strlcpy(ebc_cmd, vmwdt_cmd, MAX_CMDLEN);
|
|
ASCEBC(ebc_cmd, MAX_CMDLEN);
|
|
EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
|
|
|
|
func = vmwdt_conceal ? (wdt_init | wdt_conceal) : wdt_init;
|
|
ret = __diag288(func, vmwdt_interval, ebc_cmd, len);
|
|
kfree(ebc_cmd);
|
|
|
|
if (ret) {
|
|
printk(KERN_WARNING "%s: problem setting interval %d, "
|
|
"cmd %s\n", __FUNCTION__, vmwdt_interval,
|
|
vmwdt_cmd);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int vmwdt_disable(void)
|
|
{
|
|
int ret = __diag288(wdt_cancel, 0, "", 0);
|
|
if (ret) {
|
|
printk(KERN_WARNING "%s: problem disabling watchdog\n",
|
|
__FUNCTION__);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int __init vmwdt_probe(void)
|
|
{
|
|
/* there is no real way to see if the watchdog is supported,
|
|
* so we try initializing it with a NOP command ("BEGIN")
|
|
* that won't cause any harm even if the following disable
|
|
* fails for some reason */
|
|
static char __initdata ebc_begin[] = {
|
|
194, 197, 199, 201, 213
|
|
};
|
|
if (__diag288(wdt_init, 15, ebc_begin, sizeof(ebc_begin)) != 0) {
|
|
printk(KERN_INFO "z/VM watchdog not available\n");
|
|
return -EINVAL;
|
|
}
|
|
return vmwdt_disable();
|
|
}
|
|
|
|
static int vmwdt_open(struct inode *i, struct file *f)
|
|
{
|
|
int ret;
|
|
if (test_and_set_bit(0, &vmwdt_is_open))
|
|
return -EBUSY;
|
|
ret = vmwdt_keepalive();
|
|
if (ret)
|
|
clear_bit(0, &vmwdt_is_open);
|
|
return ret ? ret : nonseekable_open(i, f);
|
|
}
|
|
|
|
static int vmwdt_close(struct inode *i, struct file *f)
|
|
{
|
|
if (vmwdt_expect_close == 42)
|
|
vmwdt_disable();
|
|
vmwdt_expect_close = 0;
|
|
clear_bit(0, &vmwdt_is_open);
|
|
return 0;
|
|
}
|
|
|
|
static struct watchdog_info vmwdt_info = {
|
|
.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
|
|
.firmware_version = 0,
|
|
.identity = "z/VM Watchdog Timer",
|
|
};
|
|
|
|
static int vmwdt_ioctl(struct inode *i, struct file *f,
|
|
unsigned int cmd, unsigned long arg)
|
|
{
|
|
switch (cmd) {
|
|
case WDIOC_GETSUPPORT:
|
|
if (copy_to_user((void __user *)arg, &vmwdt_info,
|
|
sizeof(vmwdt_info)))
|
|
return -EFAULT;
|
|
return 0;
|
|
case WDIOC_GETSTATUS:
|
|
case WDIOC_GETBOOTSTATUS:
|
|
return put_user(0, (int __user *)arg);
|
|
case WDIOC_GETTEMP:
|
|
return -EINVAL;
|
|
case WDIOC_SETOPTIONS:
|
|
{
|
|
int options, ret;
|
|
if (get_user(options, (int __user *)arg))
|
|
return -EFAULT;
|
|
ret = -EINVAL;
|
|
if (options & WDIOS_DISABLECARD) {
|
|
ret = vmwdt_disable();
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
if (options & WDIOS_ENABLECARD) {
|
|
ret = vmwdt_keepalive();
|
|
}
|
|
return ret;
|
|
}
|
|
case WDIOC_GETTIMEOUT:
|
|
return put_user(vmwdt_interval, (int __user *)arg);
|
|
case WDIOC_SETTIMEOUT:
|
|
{
|
|
int interval;
|
|
if (get_user(interval, (int __user *)arg))
|
|
return -EFAULT;
|
|
if (interval < MIN_INTERVAL)
|
|
return -EINVAL;
|
|
vmwdt_interval = interval;
|
|
}
|
|
return vmwdt_keepalive();
|
|
case WDIOC_KEEPALIVE:
|
|
return vmwdt_keepalive();
|
|
}
|
|
|
|
return -EINVAL;
|
|
}
|
|
|
|
static ssize_t vmwdt_write(struct file *f, const char __user *buf,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
if(count) {
|
|
if (!vmwdt_nowayout) {
|
|
size_t i;
|
|
|
|
/* note: just in case someone wrote the magic character
|
|
* five months ago... */
|
|
vmwdt_expect_close = 0;
|
|
|
|
for (i = 0; i != count; i++) {
|
|
char c;
|
|
if (get_user(c, buf+i))
|
|
return -EFAULT;
|
|
if (c == 'V')
|
|
vmwdt_expect_close = 42;
|
|
}
|
|
}
|
|
/* someone wrote to us, we should restart timer */
|
|
vmwdt_keepalive();
|
|
}
|
|
return count;
|
|
}
|
|
|
|
static const struct file_operations vmwdt_fops = {
|
|
.open = &vmwdt_open,
|
|
.release = &vmwdt_close,
|
|
.ioctl = &vmwdt_ioctl,
|
|
.write = &vmwdt_write,
|
|
.owner = THIS_MODULE,
|
|
};
|
|
|
|
static struct miscdevice vmwdt_dev = {
|
|
.minor = WATCHDOG_MINOR,
|
|
.name = "watchdog",
|
|
.fops = &vmwdt_fops,
|
|
};
|
|
|
|
static int __init vmwdt_init(void)
|
|
{
|
|
int ret;
|
|
|
|
ret = vmwdt_probe();
|
|
if (ret)
|
|
return ret;
|
|
return misc_register(&vmwdt_dev);
|
|
}
|
|
module_init(vmwdt_init);
|
|
|
|
static void __exit vmwdt_exit(void)
|
|
{
|
|
WARN_ON(misc_deregister(&vmwdt_dev) != 0);
|
|
}
|
|
module_exit(vmwdt_exit);
|