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@@ -0,0 +1,191 @@
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+/*
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+ * sun4v watchdog timer
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+ * (c) Copyright 2016 Oracle Corporation
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+ *
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+ * Implement a simple watchdog driver using the built-in sun4v hypervisor
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+ * watchdog support. If time expires, the hypervisor stops or bounces
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+ * the guest domain.
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+ *
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+ * This program is free software; you can redistribute it and/or
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+ * modify it under the terms of the GNU General Public License
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+ * as published by the Free Software Foundation; either version
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+ * 2 of the License, or (at your option) any later version.
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+ */
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+
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+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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+
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+#include <linux/errno.h>
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+#include <linux/init.h>
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+#include <linux/kernel.h>
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+#include <linux/module.h>
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+#include <linux/moduleparam.h>
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+#include <linux/watchdog.h>
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+#include <asm/hypervisor.h>
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+#include <asm/mdesc.h>
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+
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+#define WDT_TIMEOUT 60
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+#define WDT_MAX_TIMEOUT 31536000
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+#define WDT_MIN_TIMEOUT 1
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+#define WDT_DEFAULT_RESOLUTION_MS 1000 /* 1 second */
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+
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+static unsigned int timeout;
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+module_param(timeout, uint, 0);
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+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default="
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+ __MODULE_STRING(WDT_TIMEOUT) ")");
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+
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+static bool nowayout = WATCHDOG_NOWAYOUT;
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+module_param(nowayout, bool, S_IRUGO);
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+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
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+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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+
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+static int sun4v_wdt_stop(struct watchdog_device *wdd)
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+{
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+ sun4v_mach_set_watchdog(0, NULL);
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+
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+ return 0;
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+}
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+
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+static int sun4v_wdt_ping(struct watchdog_device *wdd)
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+{
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+ int hverr;
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+
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+ /*
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+ * HV watchdog timer will round up the timeout
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+ * passed in to the nearest multiple of the
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+ * watchdog resolution in milliseconds.
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+ */
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+ hverr = sun4v_mach_set_watchdog(wdd->timeout * 1000, NULL);
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+ if (hverr == HV_EINVAL)
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+ return -EINVAL;
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+
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+ return 0;
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+}
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+
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+static int sun4v_wdt_set_timeout(struct watchdog_device *wdd,
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+ unsigned int timeout)
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+{
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+ wdd->timeout = timeout;
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+
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+ return 0;
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+}
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+
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+static const struct watchdog_info sun4v_wdt_ident = {
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+ .options = WDIOF_SETTIMEOUT |
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+ WDIOF_MAGICCLOSE |
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+ WDIOF_KEEPALIVEPING,
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+ .identity = "sun4v hypervisor watchdog",
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+ .firmware_version = 0,
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+};
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+
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+static struct watchdog_ops sun4v_wdt_ops = {
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+ .owner = THIS_MODULE,
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+ .start = sun4v_wdt_ping,
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+ .stop = sun4v_wdt_stop,
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+ .ping = sun4v_wdt_ping,
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+ .set_timeout = sun4v_wdt_set_timeout,
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+};
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+
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+static struct watchdog_device wdd = {
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+ .info = &sun4v_wdt_ident,
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+ .ops = &sun4v_wdt_ops,
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+ .min_timeout = WDT_MIN_TIMEOUT,
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+ .max_timeout = WDT_MAX_TIMEOUT,
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+ .timeout = WDT_TIMEOUT,
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+};
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+
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+static int __init sun4v_wdt_init(void)
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+{
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+ struct mdesc_handle *handle;
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+ u64 node;
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+ const u64 *value;
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+ int err = 0;
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+ unsigned long major = 1, minor = 1;
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+
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+ /*
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+ * There are 2 properties that can be set from the control
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+ * domain for the watchdog.
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+ * watchdog-resolution
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+ * watchdog-max-timeout
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+ *
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+ * We can expect a handle to be returned otherwise something
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+ * serious is wrong. Correct to return -ENODEV here.
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+ */
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+
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+ handle = mdesc_grab();
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+ if (!handle)
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+ return -ENODEV;
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+
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+ node = mdesc_node_by_name(handle, MDESC_NODE_NULL, "platform");
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+ err = -ENODEV;
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+ if (node == MDESC_NODE_NULL)
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+ goto out_release;
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+
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+ /*
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+ * This is a safe way to validate if we are on the right
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+ * platform.
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+ */
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+ if (sun4v_hvapi_register(HV_GRP_CORE, major, &minor))
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+ goto out_hv_unreg;
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+
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+ /* Allow value of watchdog-resolution up to 1s (default) */
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+ value = mdesc_get_property(handle, node, "watchdog-resolution", NULL);
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+ err = -EINVAL;
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+ if (value) {
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+ if (*value == 0 ||
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+ *value > WDT_DEFAULT_RESOLUTION_MS)
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+ goto out_hv_unreg;
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+ }
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+
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+ value = mdesc_get_property(handle, node, "watchdog-max-timeout", NULL);
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+ if (value) {
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+ /*
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+ * If the property value (in ms) is smaller than
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+ * min_timeout, return -EINVAL.
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+ */
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+ if (*value < wdd.min_timeout * 1000)
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+ goto out_hv_unreg;
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+
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+ /*
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+ * If the property value is smaller than
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+ * default max_timeout then set watchdog max_timeout to
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+ * the value of the property in seconds.
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+ */
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+ if (*value < wdd.max_timeout * 1000)
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+ wdd.max_timeout = *value / 1000;
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+ }
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+
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+ watchdog_init_timeout(&wdd, timeout, NULL);
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+
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+ watchdog_set_nowayout(&wdd, nowayout);
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+
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+ err = watchdog_register_device(&wdd);
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+ if (err)
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+ goto out_hv_unreg;
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+
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+ pr_info("initialized (timeout=%ds, nowayout=%d)\n",
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+ wdd.timeout, nowayout);
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+
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+ mdesc_release(handle);
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+
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+ return 0;
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+
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+out_hv_unreg:
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+ sun4v_hvapi_unregister(HV_GRP_CORE);
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+
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+out_release:
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+ mdesc_release(handle);
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+ return err;
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+}
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+
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+static void __exit sun4v_wdt_exit(void)
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+{
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+ sun4v_hvapi_unregister(HV_GRP_CORE);
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+ watchdog_unregister_device(&wdd);
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+}
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+
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+module_init(sun4v_wdt_init);
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+module_exit(sun4v_wdt_exit);
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+
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+MODULE_AUTHOR("Wim Coekaerts <wim.coekaerts@oracle.com>");
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+MODULE_DESCRIPTION("sun4v watchdog driver");
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+MODULE_LICENSE("GPL");
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Greg Kroah-Hartman