[PATCH] s390: z/VM watchdog timer.
From: Arnd Bergmann <[email protected]>
Add support for z/VM watchdog timer.
Signed-off-by: Martin Schwidefsky <[email protected]>
diffstat:
arch/s390/defconfig | 5
drivers/char/watchdog/Kconfig | 14 +
drivers/s390/Kconfig | 2
drivers/s390/char/Makefile | 2
drivers/s390/char/vmwatchdog.c | 296 +++++++++++++++++++++++++++++++++++++++++
5 files changed, 319 insertions(+)
diff -urN linux-2.6/arch/s390/defconfig linux-2.6-patched/arch/s390/defconfig
--- linux-2.6/arch/s390/defconfig 2004-10-08 19:19:10.000000000 +0200
+++ linux-2.6-patched/arch/s390/defconfig 2004-10-08 19:19:16.000000000 +0200
@@ -192,6 +192,11 @@
CONFIG_UNIX98_PTY_COUNT=2048
#
+# Watchdog Cards
+#
+# CONFIG_WATCHDOG is not set
+
+#
# S/390 character device drivers
#
CONFIG_TN3270=y
diff -urN linux-2.6/drivers/char/watchdog/Kconfig linux-2.6-patched/drivers/char/watchdog/Kconfig
--- linux-2.6/drivers/char/watchdog/Kconfig 2004-10-08 19:18:58.000000000 +0200
+++ linux-2.6-patched/drivers/char/watchdog/Kconfig 2004-10-08 19:19:16.000000000 +0200
@@ -336,6 +336,20 @@
timer expired and no process has written to /dev/watchdog during
that time.
+# S390 Architecture
+
+config ZVM_WATCHDOG
+ tristate "z/VM Watchdog Timer"
+ depends on WATCHDOG && ARCH_S390
+ help
+ IBM s/390 and zSeries machines running under z/VM 5.1 or later
+ provide a virtual watchdog timer to their guest that cause a
+ user define Control Program command to be executed after a
+ timeout.
+
+ To compile this driver as a module, choose M here. The module
+ will be called vmwatchdog.
+
# SUPERH Architecture
config SH_WDT
diff -urN linux-2.6/drivers/s390/char/Makefile linux-2.6-patched/drivers/s390/char/Makefile
--- linux-2.6/drivers/s390/char/Makefile 2004-08-14 12:55:31.000000000 +0200
+++ linux-2.6-patched/drivers/s390/char/Makefile 2004-10-08 19:19:16.000000000 +0200
@@ -17,6 +17,8 @@
obj-$(CONFIG_SCLP_VT220_TTY) += sclp_vt220.o
obj-$(CONFIG_SCLP_CPI) += sclp_cpi.o
+obj-$(CONFIG_ZVM_WATCHDOG) += vmwatchdog.o
+
tape-$(CONFIG_S390_TAPE_BLOCK) += tape_block.o
tape-$(CONFIG_PROC_FS) += tape_proc.o
tape-objs := tape_core.o tape_std.o tape_char.o $(tape-y)
diff -urN linux-2.6/drivers/s390/char/vmwatchdog.c linux-2.6-patched/drivers/s390/char/vmwatchdog.c
--- linux-2.6/drivers/s390/char/vmwatchdog.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-2.6-patched/drivers/s390/char/vmwatchdog.c 2004-10-08 19:19:16.000000000 +0200
@@ -0,0 +1,296 @@
+/*
+ * 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;
+
+#ifdef CONFIG_WATCHDOG_NOWAYOUT
+static int vmwdt_nowayout = 1;
+#else
+static int vmwdt_nowayout = 0;
+#endif
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Arnd Bergmann <[email protected]>");
+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");
+ register unsigned long __timeout asm("3");
+ register unsigned long __cmdp asm("4");
+ register unsigned long __cmdl asm("5");
+ int err;
+
+ __func = func;
+ __timeout = timeout;
+ __cmdp = virt_to_phys(cmd);
+ __cmdl = len;
+ err = 0;
+ asm volatile (
+#ifdef __s390x__
+ "diag %2,%4,0x288\n"
+ "1: \n"
+ ".section .fixup,\"ax\"\n"
+ "2: lghi %0,%1\n"
+ " jg 1b\n"
+ ".previous\n"
+ ".section __ex_table,\"a\"\n"
+ " .align 8\n"
+ " .quad 1b,2b\n"
+ ".previous\n"
+#else
+ "diag %2,%4,0x288\n"
+ "1: \n"
+ ".section .fixup,\"ax\"\n"
+ "2: lhi %0,%1\n"
+ " bras 1,3f\n"
+ " .long 1b\n"
+ "3: l 1,0(1)\n"
+ " br 1\n"
+ ".previous\n"
+ ".section __ex_table,\"a\"\n"
+ " .align 4\n"
+ " .long 1b,2b\n"
+ ".previous\n"
+#endif
+ : "+&d"(err)
+ : "i"(-EINVAL), "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;
+}
+
+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 *)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)
+{
+ /* We can't seek */
+ if(ppos != &f->f_pos)
+ return -ESPIPE;
+
+ 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 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);
diff -urN linux-2.6/drivers/s390/Kconfig linux-2.6-patched/drivers/s390/Kconfig
--- linux-2.6/drivers/s390/Kconfig 2004-08-14 12:56:01.000000000 +0200
+++ linux-2.6-patched/drivers/s390/Kconfig 2004-10-08 19:19:16.000000000 +0200
@@ -51,6 +51,8 @@
When not in use, each additional set of 256 PTYs occupy
approximately 8 KB of kernel memory on 32-bit architectures.
+source "drivers/char/watchdog/Kconfig"
+
comment "S/390 character device drivers"
config TN3270