New debugfs entry to trigger security watchdog

BZ: 35526

This patch adds an entry in the debugfs so we are now
able to trigger asecurity watchdog.

Change-Id: Id2038dde394e19c8a06d32e0d9add5f545f1b8a1
Signed-off-by: Yann Puech <yann.puech@intel.com>
Reviewed-on: http://android.intel.com:8080/47997
Reviewed-by: Romieu, Benoit <benoit.romieu@intel.com>
Tested-by: Romieu, Benoit <benoit.romieu@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>

diff --git a/drivers/watchdog/intel_scu_watchdog.c b/drivers/watchdog/intel_scu_watchdog.c
index 5cbe09d..32f90ed 100644 (file)
--- a/drivers/watchdog/intel_scu_watchdog.c
+++ b/drivers/watchdog/intel_scu_watchdog.c
@@ -71,6 +71,9 @@
 #define IPC_SET_SUB_LOAD_THRES  0x00
 #define IPC_SET_SUB_DISABLE     0x01
 #define IPC_SET_SUB_KEEPALIVE   0x02
+#ifdef CONFIG_DEBUG_FS
+#define SECURITY_WATCHDOG_ADDRESS 0xff108194
+#endif
 
 #define WDIOC_SETTIMERTIMEOUT     _IOW(WATCHDOG_IOCTL_BASE, 11, int)
 #define WDIOC_GETTIMERTIMEOUT     _IOW(WATCHDOG_IOCTL_BASE, 12, int)
@@ -81,6 +84,7 @@ static struct wake_lock watchdog_wake_lock;
 static DECLARE_WAIT_QUEUE_HEAD(read_wq);
 static unsigned char osnib_reset = OSNIB_WRITE_VALUE;
 
+
 /* The read function (intel_scu_read) waits for the warning_flag to */
 /* be set by the watchdog interrupt handler. */
 /* When warning_flag is set intel_scu_read wakes up the user level */
@@ -249,7 +253,7 @@ static int watchdog_set_timeouts(int timer_threshold, int warning_pretimeout,
 /* Keep alive  */
 static int watchdog_keepalive(void)
 {
-int ret;
+       int ret;
 
        pr_err(PFX "%s\n", __func__);
 
@@ -271,7 +275,7 @@ int ret;
 /* stops the timer */
 static int intel_scu_stop(void)
 {
-int ret;
+       int ret;
 
        pr_err(PFX "%s\n", __func__);
 
@@ -291,7 +295,7 @@ err:
 /* tasklet */
 static void watchdog_interrupt_tasklet_body(unsigned long data)
 {
-int ret;
+       int ret = 0;
 
        pr_warn(PFX "interrupt tasklet body start\n");
 
@@ -360,7 +364,7 @@ static irqreturn_t watchdog_warning_interrupt(int irq, void *dev_id)
 /* Program and starts the timer */
 static int watchdog_config_and_start(u32 newtimeout, u32 newpretimeout)
 {
-int ret;
+       int ret;
 
        timeout = newtimeout;
        pre_timeout = newpretimeout;
@@ -387,7 +391,7 @@ int ret;
 /* Open */
 static int intel_scu_open(struct inode *inode, struct file *file)
 {
-int ret;
+       int ret;
 
        /* Set flag to indicate that watchdog device is open */
        if (test_and_set_bit(0, &watchdog_device.driver_open))
@@ -476,8 +480,8 @@ static ssize_t intel_scu_write(struct file *file, char const *data, size_t len,
 static ssize_t intel_scu_read(struct file *file, char __user *user_data,
                             size_t len, loff_t *user_ppos)
 {
-int ret;
-const u8 *buf = "0";
+       int ret;
+       const u8 *buf = "0";
 
        /* we wait for the next interrupt; if more than one */
        /* interrupt has occurred since the last read, we */
@@ -504,11 +508,10 @@ const u8 *buf = "0";
 /* Poll */
 static unsigned int intel_scu_poll(struct file *file, poll_table *wait)
 {
-unsigned int mask;
+       unsigned int mask = 0;
 
        poll_wait(file, &read_wq, wait);
 
-       mask = 0;
        if (warning_flag == 1)
                mask |= POLLIN | POLLRDNORM;
 
@@ -519,10 +522,10 @@ unsigned int mask;
 static long intel_scu_ioctl(struct file *file, unsigned int cmd,
                            unsigned long arg)
 {
-void __user *argp = (void __user *)arg;
-u32 __user *p = argp;
-u32 val;
-int options;
+       void __user *argp = (void __user *)arg;
+       u32 __user *p = argp;
+       u32 val;
+       int options;
 
        static const struct watchdog_info ident = {
                .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
@@ -619,7 +622,7 @@ static int reboot_notifier(struct notifier_block *this,
                           unsigned long code,
                           void *another_unused)
 {
-int ret;
+       int ret;
 
        if (code == SYS_RESTART || code == SYS_HALT || code == SYS_POWER_OFF) {
                pr_warn(PFX "Reboot notifier\n");
@@ -635,6 +638,78 @@ int ret;
        return NOTIFY_DONE;
 }
 
+#ifdef CONFIG_DEBUG_FS
+/* This code triggers a Security Watchdog */
+int open_security(struct inode *i, struct file *f)
+{
+       int ret = 0;
+       u64 *ptr;
+       u32 value;
+
+       ptr = ioremap_nocache(SECURITY_WATCHDOG_ADDRESS, sizeof(u32));
+       if (!ptr) {
+               pr_err(PFX "cannot open secwd's debugfile\n");
+               ret = -ENODEV;
+               goto error;
+       }
+       value = readl(ptr);
+
+       pr_err(PFX "%s: This code should never be reached!!!\n", __func__);
+
+error:
+       return ret;
+}
+
+static const struct file_operations security_watchdog_fops = {
+       .open = open_security,
+};
+
+static int remove_debugfs_entries(void)
+{
+struct intel_scu_watchdog_dev *dev = &watchdog_device;
+
+       /* /sys/kernel/debug/watchdog */
+       debugfs_remove_recursive(dev->dfs_wd);
+
+       return 0;
+}
+
+static int create_debugfs_entries(void)
+{
+       struct intel_scu_watchdog_dev *dev = &watchdog_device;
+
+       /* /sys/kernel/debug/watchdog */
+       dev->dfs_wd = debugfs_create_dir("watchdog", NULL);
+       if (!dev->dfs_wd) {
+               pr_err(PFX "%s: Error, cannot create main dir\n", __func__);
+               goto error;
+       }
+
+       /* /sys/kernel/debug/watchdog/security_watchdog */
+       dev->dfs_secwd = debugfs_create_dir("security_watchdog", dev->dfs_wd);
+       if (!dev->dfs_secwd) {
+               pr_err(PFX "%s: Error, cannot create sec dir\n", __func__);
+               goto error;
+       }
+
+       /* /sys/kernel/debug/watchdog/security_watchdog/trigger */
+       dev->dfs_secwd_trigger = debugfs_create_file("trigger",
+                                   S_IFREG | S_IRUGO | S_IWUSR | S_IWGRP,
+                                   dev->dfs_secwd, NULL,
+                                   &security_watchdog_fops);
+
+       if (!dev->dfs_secwd_trigger) {
+               pr_err(PFX "%s: Error, cannot create sec file\n", __func__);
+               goto error;
+       }
+
+       return 0;
+error:
+       remove_debugfs_entries();
+       return 1;
+}
+#endif
+
 /* Kernel Interfaces */
 static const struct file_operations intel_scu_fops = {
        .owner          = THIS_MODULE,
@@ -650,7 +725,7 @@ static const struct file_operations intel_scu_fops = {
 /* Init code */
 static int __init intel_scu_watchdog_init(void)
 {
-       int ret;
+       int ret = 0;
 
        /* Check timeouts boot parameter */
        if (check_timeouts()) {
@@ -756,6 +831,10 @@ static int __init intel_scu_watchdog_init(void)
                        pr_debug(PFX "cant disable timer\n");
        }
 
+#ifdef CONFIG_DEBUG_FS
+       create_debugfs_entries();
+#endif
+
        watchdog_device.started = false;
 
        return 0;
@@ -775,9 +854,15 @@ error_stop_timer:
        return ret;
 }
 
+
 static void __exit intel_scu_watchdog_exit(void)
 {
        int ret = 0;
+
+#ifdef CONFIG_DEBUG_FS
+       remove_debugfs_entries();
+#endif
+
 #ifdef CONFIG_INTEL_SCU_SOFT_LOCKUP
        del_timer_sync(&softlock_timer);
 #endif
@@ -800,7 +885,7 @@ module_exit(intel_scu_watchdog_exit);
 
 MODULE_AUTHOR("Intel Corporation");
 MODULE_AUTHOR("mark.a.allyn@intel.com");
-MODULE_AUTHOR("yannx.puech@intel.com");
+MODULE_AUTHOR("yann.puech@intel.com");
 MODULE_DESCRIPTION("Intel SCU Watchdog Device Driver");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

diff --git a/drivers/watchdog/intel_scu_watchdog.h b/drivers/watchdog/intel_scu_watchdog.h
index 42234f1..1371a36 100644 (file)
--- a/drivers/watchdog/intel_scu_watchdog.h
+++ b/drivers/watchdog/intel_scu_watchdog.h
@@ -25,6 +25,10 @@
 #ifndef __INTEL_SCU_WATCHDOG_H
 #define __INTEL_SCU_WATCHDOG_H
 
+#ifdef CONFIG_DEBUG_FS
+#include <linux/debugfs.h>
+#endif
+
 #define PFX "intel_scu_watchdog: "
 #define WDT_VER "0.3"
 
@@ -60,6 +64,11 @@ struct intel_scu_watchdog_dev {
        struct notifier_block reboot_notifier;
        struct miscdevice miscdev;
        struct tasklet_struct interrupt_tasklet;
+#ifdef CONFIG_DEBUG_FS
+       struct dentry *dfs_wd;
+       struct dentry *dfs_secwd;
+       struct dentry *dfs_secwd_trigger;
+#endif
 };
 
 #endif /* __INTEL_SCU_WATCHDOG_H */