/*
* Watchdog implementation based on z/VM Watchdog Timer API
*
+ * Copyright IBM Corp. 2004,2009
+ *
* 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.
*/
+#define KMSG_COMPONENT "vmwatchdog"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
#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/slab.h>
+#include <linux/suspend.h>
#include <linux/watchdog.h>
#include <asm/ebcdic.h>
static unsigned long vmwdt_is_open;
static int vmwdt_expect_close;
+static DEFINE_MUTEX(vmwdt_mutex);
+
+#define VMWDT_OPEN 0 /* devnode is open or suspend in progress */
+#define VMWDT_RUNNING 1 /* The watchdog is armed */
+
enum vmwdt_func {
/* function codes */
wdt_init = 0,
"0: la %0,0\n"
"1:\n"
EX_TABLE(0b,1b)
- : "=d" (err) : "d"(__func), "d"(__timeout),
- "d"(__cmdp), "d"(__cmdl), "0" (-EINVAL) : "1", "cc");
+ : "+d" (err) : "d"(__func), "d"(__timeout),
+ "d"(__cmdp), "d"(__cmdl) : "1", "cc");
return err;
}
EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
func = vmwdt_conceal ? (wdt_init | wdt_conceal) : wdt_init;
+ set_bit(VMWDT_RUNNING, &vmwdt_is_open);
ret = __diag288(func, vmwdt_interval, ebc_cmd, len);
+ WARN_ON(ret != 0);
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__);
- }
+ WARN_ON(ret != 0);
+ clear_bit(VMWDT_RUNNING, &vmwdt_is_open);
return ret;
}
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");
+ if (__diag288(wdt_init, 15, ebc_begin, sizeof(ebc_begin)) != 0)
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))
+ if (test_and_set_bit(VMWDT_OPEN, &vmwdt_is_open))
return -EBUSY;
ret = vmwdt_keepalive();
if (ret)
- clear_bit(0, &vmwdt_is_open);
+ clear_bit(VMWDT_OPEN, &vmwdt_is_open);
return ret ? ret : nonseekable_open(i, f);
}
if (vmwdt_expect_close == 42)
vmwdt_disable();
vmwdt_expect_close = 0;
- clear_bit(0, &vmwdt_is_open);
+ clear_bit(VMWDT_OPEN, &vmwdt_is_open);
return 0;
}
.identity = "z/VM Watchdog Timer",
};
-static int vmwdt_ioctl(struct inode *i, struct file *f,
- unsigned int cmd, unsigned long arg)
+static int __vmwdt_ioctl(unsigned int cmd, unsigned long arg)
{
switch (cmd) {
case WDIOC_GETSUPPORT:
case WDIOC_KEEPALIVE:
return vmwdt_keepalive();
}
-
return -EINVAL;
}
+static long vmwdt_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
+{
+ int rc;
+
+ mutex_lock(&vmwdt_mutex);
+ rc = __vmwdt_ioctl(cmd, arg);
+ mutex_unlock(&vmwdt_mutex);
+ return (long) rc;
+}
+
static ssize_t vmwdt_write(struct file *f, const char __user *buf,
size_t count, loff_t *ppos)
{
return count;
}
-static struct file_operations vmwdt_fops = {
+static int vmwdt_resume(void)
+{
+ clear_bit(VMWDT_OPEN, &vmwdt_is_open);
+ return NOTIFY_DONE;
+}
+
+/*
+ * It makes no sense to go into suspend while the watchdog is running.
+ * Depending on the memory size, the watchdog might trigger, while we
+ * are still saving the memory.
+ * We reuse the open flag to ensure that suspend and watchdog open are
+ * exclusive operations
+ */
+static int vmwdt_suspend(void)
+{
+ if (test_and_set_bit(VMWDT_OPEN, &vmwdt_is_open)) {
+ pr_err("The system cannot be suspended while the watchdog"
+ " is in use\n");
+ return NOTIFY_BAD;
+ }
+ if (test_bit(VMWDT_RUNNING, &vmwdt_is_open)) {
+ clear_bit(VMWDT_OPEN, &vmwdt_is_open);
+ pr_err("The system cannot be suspended while the watchdog"
+ " is running\n");
+ return NOTIFY_BAD;
+ }
+ return NOTIFY_DONE;
+}
+
+/*
+ * This function is called for suspend and resume.
+ */
+static int vmwdt_power_event(struct notifier_block *this, unsigned long event,
+ void *ptr)
+{
+ switch (event) {
+ case PM_POST_HIBERNATION:
+ case PM_POST_SUSPEND:
+ return vmwdt_resume();
+ case PM_HIBERNATION_PREPARE:
+ case PM_SUSPEND_PREPARE:
+ return vmwdt_suspend();
+ default:
+ return NOTIFY_DONE;
+ }
+}
+
+static struct notifier_block vmwdt_power_notifier = {
+ .notifier_call = vmwdt_power_event,
+};
+
+static const struct file_operations vmwdt_fops = {
.open = &vmwdt_open,
.release = &vmwdt_close,
- .ioctl = &vmwdt_ioctl,
+ .unlocked_ioctl = &vmwdt_ioctl,
.write = &vmwdt_write,
.owner = THIS_MODULE,
};
ret = vmwdt_probe();
if (ret)
return ret;
- return misc_register(&vmwdt_dev);
+ ret = register_pm_notifier(&vmwdt_power_notifier);
+ if (ret)
+ return ret;
+ /*
+ * misc_register() has to be the last action in module_init(), because
+ * file operations will be available right after this.
+ */
+ ret = misc_register(&vmwdt_dev);
+ if (ret) {
+ unregister_pm_notifier(&vmwdt_power_notifier);
+ return ret;
+ }
+ return 0;
}
module_init(vmwdt_init);
static void __exit vmwdt_exit(void)
{
- WARN_ON(misc_deregister(&vmwdt_dev) != 0);
+ unregister_pm_notifier(&vmwdt_power_notifier);
+ misc_deregister(&vmwdt_dev);
}
module_exit(vmwdt_exit);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff