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linuxdebug/drivers/char/ipmi/ipmi_watchdog.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* ipmi_watchdog.c
*
* A watchdog timer based upon the IPMI interface.
*
* Author: MontaVista Software, Inc.
* Corey Minyard <minyard@mvista.com>
* source@mvista.com
*
* Copyright 2002 MontaVista Software Inc.
*/
#define pr_fmt(fmt) "IPMI Watchdog: " fmt
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/ipmi.h>
#include <linux/ipmi_smi.h>
#include <linux/mutex.h>
#include <linux/watchdog.h>
#include <linux/miscdevice.h>
#include <linux/init.h>
#include <linux/completion.h>
#include <linux/kdebug.h>
#include <linux/rwsem.h>
#include <linux/errno.h>
#include <linux/uaccess.h>
#include <linux/notifier.h>
#include <linux/nmi.h>
#include <linux/reboot.h>
#include <linux/wait.h>
#include <linux/poll.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/atomic.h>
#include <linux/sched/signal.h>
#ifdef CONFIG_X86
/*
* This is ugly, but I've determined that x86 is the only architecture
* that can reasonably support the IPMI NMI watchdog timeout at this
* time. If another architecture adds this capability somehow, it
* will have to be a somewhat different mechanism and I have no idea
* how it will work. So in the unlikely event that another
* architecture supports this, we can figure out a good generic
* mechanism for it at that time.
*/
#include <asm/kdebug.h>
#include <asm/nmi.h>
#define HAVE_DIE_NMI
#endif
/*
* The IPMI command/response information for the watchdog timer.
*/
/* values for byte 1 of the set command, byte 2 of the get response. */
#define WDOG_DONT_LOG (1 << 7)
#define WDOG_DONT_STOP_ON_SET (1 << 6)
#define WDOG_SET_TIMER_USE(byte, use) \
byte = ((byte) & 0xf8) | ((use) & 0x7)
#define WDOG_GET_TIMER_USE(byte) ((byte) & 0x7)
#define WDOG_TIMER_USE_BIOS_FRB2 1
#define WDOG_TIMER_USE_BIOS_POST 2
#define WDOG_TIMER_USE_OS_LOAD 3
#define WDOG_TIMER_USE_SMS_OS 4
#define WDOG_TIMER_USE_OEM 5
/* values for byte 2 of the set command, byte 3 of the get response. */
#define WDOG_SET_PRETIMEOUT_ACT(byte, use) \
byte = ((byte) & 0x8f) | (((use) & 0x7) << 4)
#define WDOG_GET_PRETIMEOUT_ACT(byte) (((byte) >> 4) & 0x7)
#define WDOG_PRETIMEOUT_NONE 0
#define WDOG_PRETIMEOUT_SMI 1
#define WDOG_PRETIMEOUT_NMI 2
#define WDOG_PRETIMEOUT_MSG_INT 3
/* Operations that can be performed on a pretimout. */
#define WDOG_PREOP_NONE 0
#define WDOG_PREOP_PANIC 1
/* Cause data to be available to read. Doesn't work in NMI mode. */
#define WDOG_PREOP_GIVE_DATA 2
/* Actions to perform on a full timeout. */
#define WDOG_SET_TIMEOUT_ACT(byte, use) \
byte = ((byte) & 0xf8) | ((use) & 0x7)
#define WDOG_GET_TIMEOUT_ACT(byte) ((byte) & 0x7)
#define WDOG_TIMEOUT_NONE 0
#define WDOG_TIMEOUT_RESET 1
#define WDOG_TIMEOUT_POWER_DOWN 2
#define WDOG_TIMEOUT_POWER_CYCLE 3
/*
* Byte 3 of the get command, byte 4 of the get response is the
* pre-timeout in seconds.
*/
/* Bits for setting byte 4 of the set command, byte 5 of the get response. */
#define WDOG_EXPIRE_CLEAR_BIOS_FRB2 (1 << 1)
#define WDOG_EXPIRE_CLEAR_BIOS_POST (1 << 2)
#define WDOG_EXPIRE_CLEAR_OS_LOAD (1 << 3)
#define WDOG_EXPIRE_CLEAR_SMS_OS (1 << 4)
#define WDOG_EXPIRE_CLEAR_OEM (1 << 5)
/*
* Setting/getting the watchdog timer value. This is for bytes 5 and
* 6 (the timeout time) of the set command, and bytes 6 and 7 (the
* timeout time) and 8 and 9 (the current countdown value) of the
* response. The timeout value is given in seconds (in the command it
* is 100ms intervals).
*/
#define WDOG_SET_TIMEOUT(byte1, byte2, val) \
(byte1) = (((val) * 10) & 0xff), (byte2) = (((val) * 10) >> 8)
#define WDOG_GET_TIMEOUT(byte1, byte2) \
(((byte1) | ((byte2) << 8)) / 10)
#define IPMI_WDOG_RESET_TIMER 0x22
#define IPMI_WDOG_SET_TIMER 0x24
#define IPMI_WDOG_GET_TIMER 0x25
#define IPMI_WDOG_TIMER_NOT_INIT_RESP 0x80
static DEFINE_MUTEX(ipmi_watchdog_mutex);
static bool nowayout = WATCHDOG_NOWAYOUT;
static struct ipmi_user *watchdog_user;
static int watchdog_ifnum;
/* Default the timeout to 10 seconds. */
static int timeout = 10;
/* The pre-timeout is disabled by default. */
static int pretimeout;
/* Default timeout to set on panic */
static int panic_wdt_timeout = 255;
/* Default action is to reset the board on a timeout. */
static unsigned char action_val = WDOG_TIMEOUT_RESET;
static char action[16] = "reset";
static unsigned char preaction_val = WDOG_PRETIMEOUT_NONE;
static char preaction[16] = "pre_none";
static unsigned char preop_val = WDOG_PREOP_NONE;
static char preop[16] = "preop_none";
static DEFINE_SPINLOCK(ipmi_read_lock);
static char data_to_read;
static DECLARE_WAIT_QUEUE_HEAD(read_q);
static struct fasync_struct *fasync_q;
static atomic_t pretimeout_since_last_heartbeat;
static char expect_close;
static int ifnum_to_use = -1;
/* Parameters to ipmi_set_timeout */
#define IPMI_SET_TIMEOUT_NO_HB 0
#define IPMI_SET_TIMEOUT_HB_IF_NECESSARY 1
#define IPMI_SET_TIMEOUT_FORCE_HB 2
static int ipmi_set_timeout(int do_heartbeat);
static void ipmi_register_watchdog(int ipmi_intf);
static void ipmi_unregister_watchdog(int ipmi_intf);
/*
* If true, the driver will start running as soon as it is configured
* and ready.
*/
static int start_now;
static int set_param_timeout(const char *val, const struct kernel_param *kp)
{
char *endp;
int l;
int rv = 0;
if (!val)
return -EINVAL;
l = simple_strtoul(val, &endp, 0);
if (endp == val)
return -EINVAL;
*((int *)kp->arg) = l;
if (watchdog_user)
rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
return rv;
}
static const struct kernel_param_ops param_ops_timeout = {
.set = set_param_timeout,
.get = param_get_int,
};
#define param_check_timeout param_check_int
typedef int (*action_fn)(const char *intval, char *outval);
static int action_op(const char *inval, char *outval);
static int preaction_op(const char *inval, char *outval);
static int preop_op(const char *inval, char *outval);
static void check_parms(void);
static int set_param_str(const char *val, const struct kernel_param *kp)
{
action_fn fn = (action_fn) kp->arg;
int rv = 0;
char valcp[16];
char *s;
strncpy(valcp, val, 15);
valcp[15] = '\0';
s = strstrip(valcp);
rv = fn(s, NULL);
if (rv)
goto out;
check_parms();
if (watchdog_user)
rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
out:
return rv;
}
static int get_param_str(char *buffer, const struct kernel_param *kp)
{
action_fn fn = (action_fn) kp->arg;
int rv, len;
rv = fn(NULL, buffer);
if (rv)
return rv;
len = strlen(buffer);
buffer[len++] = '\n';
buffer[len] = 0;
return len;
}
static int set_param_wdog_ifnum(const char *val, const struct kernel_param *kp)
{
int rv = param_set_int(val, kp);
if (rv)
return rv;
if ((ifnum_to_use < 0) || (ifnum_to_use == watchdog_ifnum))
return 0;
ipmi_unregister_watchdog(watchdog_ifnum);
ipmi_register_watchdog(ifnum_to_use);
return 0;
}
static const struct kernel_param_ops param_ops_wdog_ifnum = {
.set = set_param_wdog_ifnum,
.get = param_get_int,
};
#define param_check_wdog_ifnum param_check_int
static const struct kernel_param_ops param_ops_str = {
.set = set_param_str,
.get = get_param_str,
};
module_param(ifnum_to_use, wdog_ifnum, 0644);
MODULE_PARM_DESC(ifnum_to_use, "The interface number to use for the watchdog "
"timer. Setting to -1 defaults to the first registered "
"interface");
module_param(timeout, timeout, 0644);
MODULE_PARM_DESC(timeout, "Timeout value in seconds.");
module_param(pretimeout, timeout, 0644);
MODULE_PARM_DESC(pretimeout, "Pretimeout value in seconds.");
module_param(panic_wdt_timeout, timeout, 0644);
MODULE_PARM_DESC(panic_wdt_timeout, "Timeout value on kernel panic in seconds.");
module_param_cb(action, &param_ops_str, action_op, 0644);
MODULE_PARM_DESC(action, "Timeout action. One of: "
"reset, none, power_cycle, power_off.");
module_param_cb(preaction, &param_ops_str, preaction_op, 0644);
MODULE_PARM_DESC(preaction, "Pretimeout action. One of: "
"pre_none, pre_smi, pre_nmi, pre_int.");
module_param_cb(preop, &param_ops_str, preop_op, 0644);
MODULE_PARM_DESC(preop, "Pretimeout driver operation. One of: "
"preop_none, preop_panic, preop_give_data.");
module_param(start_now, int, 0444);
MODULE_PARM_DESC(start_now, "Set to 1 to start the watchdog as"
"soon as the driver is loaded.");
module_param(nowayout, bool, 0644);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
"(default=CONFIG_WATCHDOG_NOWAYOUT)");
/* Default state of the timer. */
static unsigned char ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
/* Is someone using the watchdog? Only one user is allowed. */
static unsigned long ipmi_wdog_open;
/*
* If set to 1, the heartbeat command will set the state to reset and
* start the timer. The timer doesn't normally run when the driver is
* first opened until the heartbeat is set the first time, this
* variable is used to accomplish this.
*/
static int ipmi_start_timer_on_heartbeat;
/* IPMI version of the BMC. */
static unsigned char ipmi_version_major;
static unsigned char ipmi_version_minor;
/* If a pretimeout occurs, this is used to allow only one panic to happen. */
static atomic_t preop_panic_excl = ATOMIC_INIT(-1);
#ifdef HAVE_DIE_NMI
static int testing_nmi;
static int nmi_handler_registered;
#endif
static int __ipmi_heartbeat(void);
/*
* We use a mutex to make sure that only one thing can send a set a
* message at one time. The mutex is claimed when a message is sent
* and freed when both the send and receive messages are free.
*/
static atomic_t msg_tofree = ATOMIC_INIT(0);
static DECLARE_COMPLETION(msg_wait);
static void msg_free_smi(struct ipmi_smi_msg *msg)
{
if (atomic_dec_and_test(&msg_tofree)) {
if (!oops_in_progress)
complete(&msg_wait);
}
}
static void msg_free_recv(struct ipmi_recv_msg *msg)
{
if (atomic_dec_and_test(&msg_tofree)) {
if (!oops_in_progress)
complete(&msg_wait);
}
}
static struct ipmi_smi_msg smi_msg = INIT_IPMI_SMI_MSG(msg_free_smi);
static struct ipmi_recv_msg recv_msg = INIT_IPMI_RECV_MSG(msg_free_recv);
static int __ipmi_set_timeout(struct ipmi_smi_msg *smi_msg,
struct ipmi_recv_msg *recv_msg,
int *send_heartbeat_now)
{
struct kernel_ipmi_msg msg;
unsigned char data[6];
int rv;
struct ipmi_system_interface_addr addr;
int hbnow = 0;
data[0] = 0;
WDOG_SET_TIMER_USE(data[0], WDOG_TIMER_USE_SMS_OS);
if (ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
if ((ipmi_version_major > 1) ||
((ipmi_version_major == 1) && (ipmi_version_minor >= 5))) {
/* This is an IPMI 1.5-only feature. */
data[0] |= WDOG_DONT_STOP_ON_SET;
} else {
/*
* In ipmi 1.0, setting the timer stops the watchdog, we
* need to start it back up again.
*/
hbnow = 1;
}
}
data[1] = 0;
WDOG_SET_TIMEOUT_ACT(data[1], ipmi_watchdog_state);
if ((pretimeout > 0) && (ipmi_watchdog_state != WDOG_TIMEOUT_NONE)) {
WDOG_SET_PRETIMEOUT_ACT(data[1], preaction_val);
data[2] = pretimeout;
} else {
WDOG_SET_PRETIMEOUT_ACT(data[1], WDOG_PRETIMEOUT_NONE);
data[2] = 0; /* No pretimeout. */
}
data[3] = 0;
WDOG_SET_TIMEOUT(data[4], data[5], timeout);
addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
addr.channel = IPMI_BMC_CHANNEL;
addr.lun = 0;
msg.netfn = 0x06;
msg.cmd = IPMI_WDOG_SET_TIMER;
msg.data = data;
msg.data_len = sizeof(data);
rv = ipmi_request_supply_msgs(watchdog_user,
(struct ipmi_addr *) &addr,
0,
&msg,
NULL,
smi_msg,
recv_msg,
1);
if (rv)
pr_warn("set timeout error: %d\n", rv);
else if (send_heartbeat_now)
*send_heartbeat_now = hbnow;
return rv;
}
static int _ipmi_set_timeout(int do_heartbeat)
{
int send_heartbeat_now;
int rv;
if (!watchdog_user)
return -ENODEV;
atomic_set(&msg_tofree, 2);
rv = __ipmi_set_timeout(&smi_msg,
&recv_msg,
&send_heartbeat_now);
if (rv) {
atomic_set(&msg_tofree, 0);
return rv;
}
wait_for_completion(&msg_wait);
if ((do_heartbeat == IPMI_SET_TIMEOUT_FORCE_HB)
|| ((send_heartbeat_now)
&& (do_heartbeat == IPMI_SET_TIMEOUT_HB_IF_NECESSARY)))
rv = __ipmi_heartbeat();
return rv;
}
static int ipmi_set_timeout(int do_heartbeat)
{
int rv;
mutex_lock(&ipmi_watchdog_mutex);
rv = _ipmi_set_timeout(do_heartbeat);
mutex_unlock(&ipmi_watchdog_mutex);
return rv;
}
static atomic_t panic_done_count = ATOMIC_INIT(0);
static void panic_smi_free(struct ipmi_smi_msg *msg)
{
atomic_dec(&panic_done_count);
}
static void panic_recv_free(struct ipmi_recv_msg *msg)
{
atomic_dec(&panic_done_count);
}
static struct ipmi_smi_msg panic_halt_heartbeat_smi_msg =
INIT_IPMI_SMI_MSG(panic_smi_free);
static struct ipmi_recv_msg panic_halt_heartbeat_recv_msg =
INIT_IPMI_RECV_MSG(panic_recv_free);
static void panic_halt_ipmi_heartbeat(void)
{
struct kernel_ipmi_msg msg;
struct ipmi_system_interface_addr addr;
int rv;
/*
* Don't reset the timer if we have the timer turned off, that
* re-enables the watchdog.
*/
if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
return;
addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
addr.channel = IPMI_BMC_CHANNEL;
addr.lun = 0;
msg.netfn = 0x06;
msg.cmd = IPMI_WDOG_RESET_TIMER;
msg.data = NULL;
msg.data_len = 0;
atomic_add(2, &panic_done_count);
rv = ipmi_request_supply_msgs(watchdog_user,
(struct ipmi_addr *) &addr,
0,
&msg,
NULL,
&panic_halt_heartbeat_smi_msg,
&panic_halt_heartbeat_recv_msg,
1);
if (rv)
atomic_sub(2, &panic_done_count);
}
static struct ipmi_smi_msg panic_halt_smi_msg =
INIT_IPMI_SMI_MSG(panic_smi_free);
static struct ipmi_recv_msg panic_halt_recv_msg =
INIT_IPMI_RECV_MSG(panic_recv_free);
/*
* Special call, doesn't claim any locks. This is only to be called
* at panic or halt time, in run-to-completion mode, when the caller
* is the only CPU and the only thing that will be going is these IPMI
* calls.
*/
static void panic_halt_ipmi_set_timeout(void)
{
int send_heartbeat_now;
int rv;
/* Wait for the messages to be free. */
while (atomic_read(&panic_done_count) != 0)
ipmi_poll_interface(watchdog_user);
atomic_add(2, &panic_done_count);
rv = __ipmi_set_timeout(&panic_halt_smi_msg,
&panic_halt_recv_msg,
&send_heartbeat_now);
if (rv) {
atomic_sub(2, &panic_done_count);
pr_warn("Unable to extend the watchdog timeout\n");
} else {
if (send_heartbeat_now)
panic_halt_ipmi_heartbeat();
}
while (atomic_read(&panic_done_count) != 0)
ipmi_poll_interface(watchdog_user);
}
static int __ipmi_heartbeat(void)
{
struct kernel_ipmi_msg msg;
int rv;
struct ipmi_system_interface_addr addr;
int timeout_retries = 0;
restart:
/*
* Don't reset the timer if we have the timer turned off, that
* re-enables the watchdog.
*/
if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
return 0;
atomic_set(&msg_tofree, 2);
addr.addr_type = IPMI_SYSTEM_INTERFACE_ADDR_TYPE;
addr.channel = IPMI_BMC_CHANNEL;
addr.lun = 0;
msg.netfn = 0x06;
msg.cmd = IPMI_WDOG_RESET_TIMER;
msg.data = NULL;
msg.data_len = 0;
rv = ipmi_request_supply_msgs(watchdog_user,
(struct ipmi_addr *) &addr,
0,
&msg,
NULL,
&smi_msg,
&recv_msg,
1);
if (rv) {
atomic_set(&msg_tofree, 0);
pr_warn("heartbeat send failure: %d\n", rv);
return rv;
}
/* Wait for the heartbeat to be sent. */
wait_for_completion(&msg_wait);
if (recv_msg.msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP) {
timeout_retries++;
if (timeout_retries > 3) {
pr_err("Unable to restore the IPMI watchdog's settings, giving up\n");
rv = -EIO;
goto out;
}
/*
* The timer was not initialized, that means the BMC was
* probably reset and lost the watchdog information. Attempt
* to restore the timer's info. Note that we still hold
* the heartbeat lock, to keep a heartbeat from happening
* in this process, so must say no heartbeat to avoid a
* deadlock on this mutex
*/
rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
if (rv) {
pr_err("Unable to send the command to set the watchdog's settings, giving up\n");
goto out;
}
/* Might need a heartbeat send, go ahead and do it. */
goto restart;
} else if (recv_msg.msg.data[0] != 0) {
/*
* Got an error in the heartbeat response. It was already
* reported in ipmi_wdog_msg_handler, but we should return
* an error here.
*/
rv = -EINVAL;
}
out:
return rv;
}
static int _ipmi_heartbeat(void)
{
int rv;
if (!watchdog_user)
return -ENODEV;
if (ipmi_start_timer_on_heartbeat) {
ipmi_start_timer_on_heartbeat = 0;
ipmi_watchdog_state = action_val;
rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
} else if (atomic_cmpxchg(&pretimeout_since_last_heartbeat, 1, 0)) {
/*
* A pretimeout occurred, make sure we set the timeout.
* We don't want to set the action, though, we want to
* leave that alone (thus it can't be combined with the
* above operation.
*/
rv = _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
} else {
rv = __ipmi_heartbeat();
}
return rv;
}
static int ipmi_heartbeat(void)
{
int rv;
mutex_lock(&ipmi_watchdog_mutex);
rv = _ipmi_heartbeat();
mutex_unlock(&ipmi_watchdog_mutex);
return rv;
}
static const struct watchdog_info ident = {
.options = 0, /* WDIOF_SETTIMEOUT, */
.firmware_version = 1,
.identity = "IPMI"
};
static int ipmi_ioctl(struct file *file,
unsigned int cmd, unsigned long arg)
{
void __user *argp = (void __user *)arg;
int i;
int val;
switch (cmd) {
case WDIOC_GETSUPPORT:
i = copy_to_user(argp, &ident, sizeof(ident));
return i ? -EFAULT : 0;
case WDIOC_SETTIMEOUT:
i = copy_from_user(&val, argp, sizeof(int));
if (i)
return -EFAULT;
timeout = val;
return _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
case WDIOC_GETTIMEOUT:
i = copy_to_user(argp, &timeout, sizeof(timeout));
if (i)
return -EFAULT;
return 0;
case WDIOC_SETPRETIMEOUT:
i = copy_from_user(&val, argp, sizeof(int));
if (i)
return -EFAULT;
pretimeout = val;
return _ipmi_set_timeout(IPMI_SET_TIMEOUT_HB_IF_NECESSARY);
case WDIOC_GETPRETIMEOUT:
i = copy_to_user(argp, &pretimeout, sizeof(pretimeout));
if (i)
return -EFAULT;
return 0;
case WDIOC_KEEPALIVE:
return _ipmi_heartbeat();
case WDIOC_SETOPTIONS:
i = copy_from_user(&val, argp, sizeof(int));
if (i)
return -EFAULT;
if (val & WDIOS_DISABLECARD) {
ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
_ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
ipmi_start_timer_on_heartbeat = 0;
}
if (val & WDIOS_ENABLECARD) {
ipmi_watchdog_state = action_val;
_ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
}
return 0;
case WDIOC_GETSTATUS:
val = 0;
i = copy_to_user(argp, &val, sizeof(val));
if (i)
return -EFAULT;
return 0;
default:
return -ENOIOCTLCMD;
}
}
static long ipmi_unlocked_ioctl(struct file *file,
unsigned int cmd,
unsigned long arg)
{
int ret;
mutex_lock(&ipmi_watchdog_mutex);
ret = ipmi_ioctl(file, cmd, arg);
mutex_unlock(&ipmi_watchdog_mutex);
return ret;
}
static ssize_t ipmi_write(struct file *file,
const char __user *buf,
size_t len,
loff_t *ppos)
{
int rv;
if (len) {
if (!nowayout) {
size_t i;
/* In case it was set long ago */
expect_close = 0;
for (i = 0; i != len; i++) {
char c;
if (get_user(c, buf + i))
return -EFAULT;
if (c == 'V')
expect_close = 42;
}
}
rv = ipmi_heartbeat();
if (rv)
return rv;
}
return len;
}
static ssize_t ipmi_read(struct file *file,
char __user *buf,
size_t count,
loff_t *ppos)
{
int rv = 0;
wait_queue_entry_t wait;
if (count <= 0)
return 0;
/*
* Reading returns if the pretimeout has gone off, and it only does
* it once per pretimeout.
*/
spin_lock_irq(&ipmi_read_lock);
if (!data_to_read) {
if (file->f_flags & O_NONBLOCK) {
rv = -EAGAIN;
goto out;
}
init_waitqueue_entry(&wait, current);
add_wait_queue(&read_q, &wait);
while (!data_to_read) {
set_current_state(TASK_INTERRUPTIBLE);
spin_unlock_irq(&ipmi_read_lock);
schedule();
spin_lock_irq(&ipmi_read_lock);
}
remove_wait_queue(&read_q, &wait);
if (signal_pending(current)) {
rv = -ERESTARTSYS;
goto out;
}
}
data_to_read = 0;
out:
spin_unlock_irq(&ipmi_read_lock);
if (rv == 0) {
if (copy_to_user(buf, &data_to_read, 1))
rv = -EFAULT;
else
rv = 1;
}
return rv;
}
static int ipmi_open(struct inode *ino, struct file *filep)
{
switch (iminor(ino)) {
case WATCHDOG_MINOR:
if (test_and_set_bit(0, &ipmi_wdog_open))
return -EBUSY;
/*
* Don't start the timer now, let it start on the
* first heartbeat.
*/
ipmi_start_timer_on_heartbeat = 1;
return stream_open(ino, filep);
default:
return (-ENODEV);
}
}
static __poll_t ipmi_poll(struct file *file, poll_table *wait)
{
__poll_t mask = 0;
poll_wait(file, &read_q, wait);
spin_lock_irq(&ipmi_read_lock);
if (data_to_read)
mask |= (EPOLLIN | EPOLLRDNORM);
spin_unlock_irq(&ipmi_read_lock);
return mask;
}
static int ipmi_fasync(int fd, struct file *file, int on)
{
int result;
result = fasync_helper(fd, file, on, &fasync_q);
return (result);
}
static int ipmi_close(struct inode *ino, struct file *filep)
{
if (iminor(ino) == WATCHDOG_MINOR) {
if (expect_close == 42) {
mutex_lock(&ipmi_watchdog_mutex);
ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
_ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
mutex_unlock(&ipmi_watchdog_mutex);
} else {
pr_crit("Unexpected close, not stopping watchdog!\n");
ipmi_heartbeat();
}
clear_bit(0, &ipmi_wdog_open);
}
expect_close = 0;
return 0;
}
static const struct file_operations ipmi_wdog_fops = {
.owner = THIS_MODULE,
.read = ipmi_read,
.poll = ipmi_poll,
.write = ipmi_write,
.unlocked_ioctl = ipmi_unlocked_ioctl,
.compat_ioctl = compat_ptr_ioctl,
.open = ipmi_open,
.release = ipmi_close,
.fasync = ipmi_fasync,
.llseek = no_llseek,
};
static struct miscdevice ipmi_wdog_miscdev = {
.minor = WATCHDOG_MINOR,
.name = "watchdog",
.fops = &ipmi_wdog_fops
};
static void ipmi_wdog_msg_handler(struct ipmi_recv_msg *msg,
void *handler_data)
{
if (msg->msg.cmd == IPMI_WDOG_RESET_TIMER &&
msg->msg.data[0] == IPMI_WDOG_TIMER_NOT_INIT_RESP)
pr_info("response: The IPMI controller appears to have been reset, will attempt to reinitialize the watchdog timer\n");
else if (msg->msg.data[0] != 0)
pr_err("response: Error %x on cmd %x\n",
msg->msg.data[0],
msg->msg.cmd);
ipmi_free_recv_msg(msg);
}
static void ipmi_wdog_pretimeout_handler(void *handler_data)
{
if (preaction_val != WDOG_PRETIMEOUT_NONE) {
if (preop_val == WDOG_PREOP_PANIC) {
if (atomic_inc_and_test(&preop_panic_excl))
panic("Watchdog pre-timeout");
} else if (preop_val == WDOG_PREOP_GIVE_DATA) {
unsigned long flags;
spin_lock_irqsave(&ipmi_read_lock, flags);
data_to_read = 1;
wake_up_interruptible(&read_q);
kill_fasync(&fasync_q, SIGIO, POLL_IN);
spin_unlock_irqrestore(&ipmi_read_lock, flags);
}
}
/*
* On some machines, the heartbeat will give an error and not
* work unless we re-enable the timer. So do so.
*/
atomic_set(&pretimeout_since_last_heartbeat, 1);
}
static void ipmi_wdog_panic_handler(void *user_data)
{
static int panic_event_handled;
/*
* On a panic, if we have a panic timeout, make sure to extend
* the watchdog timer to a reasonable value to complete the
* panic, if the watchdog timer is running. Plus the
* pretimeout is meaningless at panic time.
*/
if (watchdog_user && !panic_event_handled &&
ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
/* Make sure we do this only once. */
panic_event_handled = 1;
timeout = panic_wdt_timeout;
pretimeout = 0;
panic_halt_ipmi_set_timeout();
}
}
static const struct ipmi_user_hndl ipmi_hndlrs = {
.ipmi_recv_hndl = ipmi_wdog_msg_handler,
.ipmi_watchdog_pretimeout = ipmi_wdog_pretimeout_handler,
.ipmi_panic_handler = ipmi_wdog_panic_handler
};
static void ipmi_register_watchdog(int ipmi_intf)
{
int rv = -EBUSY;
if (watchdog_user)
goto out;
if ((ifnum_to_use >= 0) && (ifnum_to_use != ipmi_intf))
goto out;
watchdog_ifnum = ipmi_intf;
rv = ipmi_create_user(ipmi_intf, &ipmi_hndlrs, NULL, &watchdog_user);
if (rv < 0) {
pr_crit("Unable to register with ipmi\n");
goto out;
}
rv = ipmi_get_version(watchdog_user,
&ipmi_version_major,
&ipmi_version_minor);
if (rv) {
pr_warn("Unable to get IPMI version, assuming 1.0\n");
ipmi_version_major = 1;
ipmi_version_minor = 0;
}
rv = misc_register(&ipmi_wdog_miscdev);
if (rv < 0) {
ipmi_destroy_user(watchdog_user);
watchdog_user = NULL;
pr_crit("Unable to register misc device\n");
}
#ifdef HAVE_DIE_NMI
if (nmi_handler_registered) {
int old_pretimeout = pretimeout;
int old_timeout = timeout;
int old_preop_val = preop_val;
/*
* Set the pretimeout to go off in a second and give
* ourselves plenty of time to stop the timer.
*/
ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
preop_val = WDOG_PREOP_NONE; /* Make sure nothing happens */
pretimeout = 99;
timeout = 100;
testing_nmi = 1;
rv = ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
if (rv) {
pr_warn("Error starting timer to test NMI: 0x%x. The NMI pretimeout will likely not work\n",
rv);
rv = 0;
goto out_restore;
}
msleep(1500);
if (testing_nmi != 2) {
pr_warn("IPMI NMI didn't seem to occur. The NMI pretimeout will likely not work\n");
}
out_restore:
testing_nmi = 0;
preop_val = old_preop_val;
pretimeout = old_pretimeout;
timeout = old_timeout;
}
#endif
out:
if ((start_now) && (rv == 0)) {
/* Run from startup, so start the timer now. */
start_now = 0; /* Disable this function after first startup. */
ipmi_watchdog_state = action_val;
ipmi_set_timeout(IPMI_SET_TIMEOUT_FORCE_HB);
pr_info("Starting now!\n");
} else {
/* Stop the timer now. */
ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
}
}
static void ipmi_unregister_watchdog(int ipmi_intf)
{
int rv;
struct ipmi_user *loc_user = watchdog_user;
if (!loc_user)
return;
if (watchdog_ifnum != ipmi_intf)
return;
/* Make sure no one can call us any more. */
misc_deregister(&ipmi_wdog_miscdev);
watchdog_user = NULL;
/*
* Wait to make sure the message makes it out. The lower layer has
* pointers to our buffers, we want to make sure they are done before
* we release our memory.
*/
while (atomic_read(&msg_tofree))
msg_free_smi(NULL);
mutex_lock(&ipmi_watchdog_mutex);
/* Disconnect from IPMI. */
rv = ipmi_destroy_user(loc_user);
if (rv)
pr_warn("error unlinking from IPMI: %d\n", rv);
/* If it comes back, restart it properly. */
ipmi_start_timer_on_heartbeat = 1;
mutex_unlock(&ipmi_watchdog_mutex);
}
#ifdef HAVE_DIE_NMI
static int
ipmi_nmi(unsigned int val, struct pt_regs *regs)
{
/*
* If we get here, it's an NMI that's not a memory or I/O
* error. We can't truly tell if it's from IPMI or not
* without sending a message, and sending a message is almost
* impossible because of locking.
*/
if (testing_nmi) {
testing_nmi = 2;
return NMI_HANDLED;
}
/* If we are not expecting a timeout, ignore it. */
if (ipmi_watchdog_state == WDOG_TIMEOUT_NONE)
return NMI_DONE;
if (preaction_val != WDOG_PRETIMEOUT_NMI)
return NMI_DONE;
/*
* If no one else handled the NMI, we assume it was the IPMI
* watchdog.
*/
if (preop_val == WDOG_PREOP_PANIC) {
/* On some machines, the heartbeat will give
an error and not work unless we re-enable
the timer. So do so. */
atomic_set(&pretimeout_since_last_heartbeat, 1);
if (atomic_inc_and_test(&preop_panic_excl))
nmi_panic(regs, "pre-timeout");
}
return NMI_HANDLED;
}
#endif
static int wdog_reboot_handler(struct notifier_block *this,
unsigned long code,
void *unused)
{
static int reboot_event_handled;
if ((watchdog_user) && (!reboot_event_handled)) {
/* Make sure we only do this once. */
reboot_event_handled = 1;
if (code == SYS_POWER_OFF || code == SYS_HALT) {
/* Disable the WDT if we are shutting down. */
ipmi_watchdog_state = WDOG_TIMEOUT_NONE;
ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
} else if (ipmi_watchdog_state != WDOG_TIMEOUT_NONE) {
/* Set a long timer to let the reboot happen or
reset if it hangs, but only if the watchdog
timer was already running. */
if (timeout < 120)
timeout = 120;
pretimeout = 0;
ipmi_watchdog_state = WDOG_TIMEOUT_RESET;
ipmi_set_timeout(IPMI_SET_TIMEOUT_NO_HB);
}
}
return NOTIFY_OK;
}
static struct notifier_block wdog_reboot_notifier = {
.notifier_call = wdog_reboot_handler,
.next = NULL,
.priority = 0
};
static void ipmi_new_smi(int if_num, struct device *device)
{
ipmi_register_watchdog(if_num);
}
static void ipmi_smi_gone(int if_num)
{
ipmi_unregister_watchdog(if_num);
}
static struct ipmi_smi_watcher smi_watcher = {
.owner = THIS_MODULE,
.new_smi = ipmi_new_smi,
.smi_gone = ipmi_smi_gone
};
static int action_op(const char *inval, char *outval)
{
if (outval)
strcpy(outval, action);
if (!inval)
return 0;
if (strcmp(inval, "reset") == 0)
action_val = WDOG_TIMEOUT_RESET;
else if (strcmp(inval, "none") == 0)
action_val = WDOG_TIMEOUT_NONE;
else if (strcmp(inval, "power_cycle") == 0)
action_val = WDOG_TIMEOUT_POWER_CYCLE;
else if (strcmp(inval, "power_off") == 0)
action_val = WDOG_TIMEOUT_POWER_DOWN;
else
return -EINVAL;
strcpy(action, inval);
return 0;
}
static int preaction_op(const char *inval, char *outval)
{
if (outval)
strcpy(outval, preaction);
if (!inval)
return 0;
if (strcmp(inval, "pre_none") == 0)
preaction_val = WDOG_PRETIMEOUT_NONE;
else if (strcmp(inval, "pre_smi") == 0)
preaction_val = WDOG_PRETIMEOUT_SMI;
#ifdef HAVE_DIE_NMI
else if (strcmp(inval, "pre_nmi") == 0)
preaction_val = WDOG_PRETIMEOUT_NMI;
#endif
else if (strcmp(inval, "pre_int") == 0)
preaction_val = WDOG_PRETIMEOUT_MSG_INT;
else
return -EINVAL;
strcpy(preaction, inval);
return 0;
}
static int preop_op(const char *inval, char *outval)
{
if (outval)
strcpy(outval, preop);
if (!inval)
return 0;
if (strcmp(inval, "preop_none") == 0)
preop_val = WDOG_PREOP_NONE;
else if (strcmp(inval, "preop_panic") == 0)
preop_val = WDOG_PREOP_PANIC;
else if (strcmp(inval, "preop_give_data") == 0)
preop_val = WDOG_PREOP_GIVE_DATA;
else
return -EINVAL;
strcpy(preop, inval);
return 0;
}
static void check_parms(void)
{
#ifdef HAVE_DIE_NMI
int do_nmi = 0;
int rv;
if (preaction_val == WDOG_PRETIMEOUT_NMI) {
do_nmi = 1;
if (preop_val == WDOG_PREOP_GIVE_DATA) {
pr_warn("Pretimeout op is to give data but NMI pretimeout is enabled, setting pretimeout op to none\n");
preop_op("preop_none", NULL);
do_nmi = 0;
}
}
if (do_nmi && !nmi_handler_registered) {
rv = register_nmi_handler(NMI_UNKNOWN, ipmi_nmi, 0,
"ipmi");
if (rv) {
pr_warn("Can't register nmi handler\n");
return;
} else
nmi_handler_registered = 1;
} else if (!do_nmi && nmi_handler_registered) {
unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
nmi_handler_registered = 0;
}
#endif
}
static int __init ipmi_wdog_init(void)
{
int rv;
if (action_op(action, NULL)) {
action_op("reset", NULL);
pr_info("Unknown action '%s', defaulting to reset\n", action);
}
if (preaction_op(preaction, NULL)) {
preaction_op("pre_none", NULL);
pr_info("Unknown preaction '%s', defaulting to none\n",
preaction);
}
if (preop_op(preop, NULL)) {
preop_op("preop_none", NULL);
pr_info("Unknown preop '%s', defaulting to none\n", preop);
}
check_parms();
register_reboot_notifier(&wdog_reboot_notifier);
rv = ipmi_smi_watcher_register(&smi_watcher);
if (rv) {
#ifdef HAVE_DIE_NMI
if (nmi_handler_registered)
unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
#endif
unregister_reboot_notifier(&wdog_reboot_notifier);
pr_warn("can't register smi watcher\n");
return rv;
}
pr_info("driver initialized\n");
return 0;
}
static void __exit ipmi_wdog_exit(void)
{
ipmi_smi_watcher_unregister(&smi_watcher);
ipmi_unregister_watchdog(watchdog_ifnum);
#ifdef HAVE_DIE_NMI
if (nmi_handler_registered)
unregister_nmi_handler(NMI_UNKNOWN, "ipmi");
#endif
unregister_reboot_notifier(&wdog_reboot_notifier);
}
module_exit(ipmi_wdog_exit);
module_init(ipmi_wdog_init);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Corey Minyard <minyard@mvista.com>");
MODULE_DESCRIPTION("watchdog timer based upon the IPMI interface.");
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