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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 | /* * sun4v watchdog timer * (c) Copyright 2016 Oracle Corporation * * Implement a simple watchdog driver using the built-in sun4v hypervisor * watchdog support. If time expires, the hypervisor stops or bounces * the guest domain. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/errno.h> #include <linux/init.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/watchdog.h> #include <asm/hypervisor.h> #include <asm/mdesc.h> #define WDT_TIMEOUT 60 #define WDT_MAX_TIMEOUT 31536000 #define WDT_MIN_TIMEOUT 1 #define WDT_DEFAULT_RESOLUTION_MS 1000 /* 1 second */ static unsigned int timeout; module_param(timeout, uint, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds (default=" __MODULE_STRING(WDT_TIMEOUT) ")"); static bool nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, bool, S_IRUGO); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); static int sun4v_wdt_stop(struct watchdog_device *wdd) { sun4v_mach_set_watchdog(0, NULL); return 0; } static int sun4v_wdt_ping(struct watchdog_device *wdd) { int hverr; /* * HV watchdog timer will round up the timeout * passed in to the nearest multiple of the * watchdog resolution in milliseconds. */ hverr = sun4v_mach_set_watchdog(wdd->timeout * 1000, NULL); if (hverr == HV_EINVAL) return -EINVAL; return 0; } static int sun4v_wdt_set_timeout(struct watchdog_device *wdd, unsigned int timeout) { wdd->timeout = timeout; return 0; } static const struct watchdog_info sun4v_wdt_ident = { .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, .identity = "sun4v hypervisor watchdog", .firmware_version = 0, }; static const struct watchdog_ops sun4v_wdt_ops = { .owner = THIS_MODULE, .start = sun4v_wdt_ping, .stop = sun4v_wdt_stop, .ping = sun4v_wdt_ping, .set_timeout = sun4v_wdt_set_timeout, }; static struct watchdog_device wdd = { .info = &sun4v_wdt_ident, .ops = &sun4v_wdt_ops, .min_timeout = WDT_MIN_TIMEOUT, .max_timeout = WDT_MAX_TIMEOUT, .timeout = WDT_TIMEOUT, }; static int __init sun4v_wdt_init(void) { struct mdesc_handle *handle; u64 node; const u64 *value; int err = 0; unsigned long major = 1, minor = 1; /* * There are 2 properties that can be set from the control * domain for the watchdog. * watchdog-resolution * watchdog-max-timeout * * We can expect a handle to be returned otherwise something * serious is wrong. Correct to return -ENODEV here. */ handle = mdesc_grab(); if (!handle) return -ENODEV; node = mdesc_node_by_name(handle, MDESC_NODE_NULL, "platform"); err = -ENODEV; if (node == MDESC_NODE_NULL) goto out_release; /* * This is a safe way to validate if we are on the right * platform. */ if (sun4v_hvapi_register(HV_GRP_CORE, major, &minor)) goto out_hv_unreg; /* Allow value of watchdog-resolution up to 1s (default) */ value = mdesc_get_property(handle, node, "watchdog-resolution", NULL); err = -EINVAL; if (value) { if (*value == 0 || *value > WDT_DEFAULT_RESOLUTION_MS) goto out_hv_unreg; } value = mdesc_get_property(handle, node, "watchdog-max-timeout", NULL); if (value) { /* * If the property value (in ms) is smaller than * min_timeout, return -EINVAL. */ if (*value < wdd.min_timeout * 1000) goto out_hv_unreg; /* * If the property value is smaller than * default max_timeout then set watchdog max_timeout to * the value of the property in seconds. */ if (*value < wdd.max_timeout * 1000) wdd.max_timeout = *value / 1000; } watchdog_init_timeout(&wdd, timeout, NULL); watchdog_set_nowayout(&wdd, nowayout); err = watchdog_register_device(&wdd); if (err) goto out_hv_unreg; pr_info("initialized (timeout=%ds, nowayout=%d)\n", wdd.timeout, nowayout); mdesc_release(handle); return 0; out_hv_unreg: sun4v_hvapi_unregister(HV_GRP_CORE); out_release: mdesc_release(handle); return err; } static void __exit sun4v_wdt_exit(void) { sun4v_hvapi_unregister(HV_GRP_CORE); watchdog_unregister_device(&wdd); } module_init(sun4v_wdt_init); module_exit(sun4v_wdt_exit); MODULE_AUTHOR("Wim Coekaerts <wim.coekaerts@oracle.com>"); MODULE_DESCRIPTION("sun4v watchdog driver"); MODULE_LICENSE("GPL"); |