Commit | Line | Data |
---|---|---|
f7a94db4 | 1 | /* |
646f919e | 2 | * Watchdog driver for z/VM and LPAR using the diag 288 interface. |
f7a94db4 PH |
3 | * |
4 | * Under z/VM, expiration of the watchdog will send a "system restart" command | |
5 | * to CP. | |
6 | * | |
646f919e PH |
7 | * The command can be altered using the module parameter "cmd". This is |
8 | * not recommended because it's only supported on z/VM but not whith LPAR. | |
9 | * | |
10 | * On LPAR, the watchdog will always trigger a system restart. the module | |
11 | * paramter cmd is meaningless here. | |
12 | * | |
f7a94db4 PH |
13 | * |
14 | * Copyright IBM Corp. 2004, 2013 | |
15 | * Author(s): Arnd Bergmann (arndb@de.ibm.com) | |
16 | * Philipp Hachtmann (phacht@de.ibm.com) | |
17 | * | |
18 | */ | |
19 | ||
20 | #define KMSG_COMPONENT "diag288_wdt" | |
21 | #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt | |
22 | ||
23 | #include <linux/init.h> | |
24 | #include <linux/kernel.h> | |
25 | #include <linux/module.h> | |
26 | #include <linux/moduleparam.h> | |
27 | #include <linux/slab.h> | |
28 | #include <linux/miscdevice.h> | |
29 | #include <linux/watchdog.h> | |
30 | #include <linux/suspend.h> | |
31 | #include <asm/ebcdic.h> | |
1ec2772e | 32 | #include <asm/diag.h> |
f7a94db4 PH |
33 | #include <linux/io.h> |
34 | #include <linux/uaccess.h> | |
35 | ||
36 | #define MAX_CMDLEN 240 | |
37 | #define DEFAULT_CMD "SYSTEM RESTART" | |
38 | ||
39 | #define MIN_INTERVAL 15 /* Minimal time supported by diag88 */ | |
40 | #define MAX_INTERVAL 3600 /* One hour should be enough - pure estimation */ | |
41 | ||
42 | #define WDT_DEFAULT_TIMEOUT 30 | |
43 | ||
44 | /* Function codes - init, change, cancel */ | |
45 | #define WDT_FUNC_INIT 0 | |
46 | #define WDT_FUNC_CHANGE 1 | |
47 | #define WDT_FUNC_CANCEL 2 | |
48 | #define WDT_FUNC_CONCEAL 0x80000000 | |
49 | ||
646f919e PH |
50 | /* Action codes for LPAR watchdog */ |
51 | #define LPARWDT_RESTART 0 | |
52 | ||
f7a94db4 PH |
53 | static char wdt_cmd[MAX_CMDLEN] = DEFAULT_CMD; |
54 | static bool conceal_on; | |
55 | static bool nowayout_info = WATCHDOG_NOWAYOUT; | |
56 | ||
57 | MODULE_LICENSE("GPL"); | |
58 | MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>"); | |
59 | MODULE_AUTHOR("Philipp Hachtmann <phacht@de.ibm.com>"); | |
60 | ||
61 | MODULE_DESCRIPTION("System z diag288 Watchdog Timer"); | |
62 | ||
63 | module_param_string(cmd, wdt_cmd, MAX_CMDLEN, 0644); | |
64 | MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers (z/VM only)"); | |
65 | ||
66 | module_param_named(conceal, conceal_on, bool, 0644); | |
67 | MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog is active (z/VM only)"); | |
68 | ||
69 | module_param_named(nowayout, nowayout_info, bool, 0444); | |
70 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = CONFIG_WATCHDOG_NOWAYOUT)"); | |
71 | ||
72 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | |
73 | MODULE_ALIAS("vmwatchdog"); | |
74 | ||
75 | static int __diag288(unsigned int func, unsigned int timeout, | |
76 | unsigned long action, unsigned int len) | |
77 | { | |
78 | register unsigned long __func asm("2") = func; | |
79 | register unsigned long __timeout asm("3") = timeout; | |
80 | register unsigned long __action asm("4") = action; | |
81 | register unsigned long __len asm("5") = len; | |
82 | int err; | |
83 | ||
84 | err = -EINVAL; | |
85 | asm volatile( | |
86 | " diag %1, %3, 0x288\n" | |
87 | "0: la %0, 0\n" | |
88 | "1:\n" | |
89 | EX_TABLE(0b, 1b) | |
90 | : "+d" (err) : "d"(__func), "d"(__timeout), | |
91 | "d"(__action), "d"(__len) : "1", "cc"); | |
92 | return err; | |
93 | } | |
94 | ||
95 | static int __diag288_vm(unsigned int func, unsigned int timeout, | |
96 | char *cmd, size_t len) | |
97 | { | |
1ec2772e | 98 | diag_stat_inc(DIAG_STAT_X288); |
f7a94db4 PH |
99 | return __diag288(func, timeout, virt_to_phys(cmd), len); |
100 | } | |
101 | ||
646f919e PH |
102 | static int __diag288_lpar(unsigned int func, unsigned int timeout, |
103 | unsigned long action) | |
104 | { | |
1ec2772e | 105 | diag_stat_inc(DIAG_STAT_X288); |
646f919e PH |
106 | return __diag288(func, timeout, action, 0); |
107 | } | |
108 | ||
f7a94db4 PH |
109 | static int wdt_start(struct watchdog_device *dev) |
110 | { | |
111 | char *ebc_cmd; | |
112 | size_t len; | |
113 | int ret; | |
114 | unsigned int func; | |
115 | ||
116 | ret = -ENODEV; | |
117 | ||
118 | if (MACHINE_IS_VM) { | |
119 | ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL); | |
120 | if (!ebc_cmd) | |
121 | return -ENOMEM; | |
122 | len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN); | |
123 | ASCEBC(ebc_cmd, MAX_CMDLEN); | |
124 | EBC_TOUPPER(ebc_cmd, MAX_CMDLEN); | |
125 | ||
126 | func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL) | |
127 | : WDT_FUNC_INIT; | |
128 | ret = __diag288_vm(func, dev->timeout, ebc_cmd, len); | |
129 | WARN_ON(ret != 0); | |
130 | kfree(ebc_cmd); | |
b2527d20 | 131 | } else { |
646f919e PH |
132 | ret = __diag288_lpar(WDT_FUNC_INIT, |
133 | dev->timeout, LPARWDT_RESTART); | |
134 | } | |
135 | ||
f7a94db4 PH |
136 | if (ret) { |
137 | pr_err("The watchdog cannot be activated\n"); | |
138 | return ret; | |
139 | } | |
f7a94db4 PH |
140 | return 0; |
141 | } | |
142 | ||
143 | static int wdt_stop(struct watchdog_device *dev) | |
144 | { | |
145 | int ret; | |
146 | ||
1ec2772e | 147 | diag_stat_inc(DIAG_STAT_X288); |
f7a94db4 | 148 | ret = __diag288(WDT_FUNC_CANCEL, 0, 0, 0); |
f7a94db4 PH |
149 | return ret; |
150 | } | |
151 | ||
152 | static int wdt_ping(struct watchdog_device *dev) | |
153 | { | |
154 | char *ebc_cmd; | |
155 | size_t len; | |
156 | int ret; | |
157 | unsigned int func; | |
158 | ||
159 | ret = -ENODEV; | |
160 | ||
161 | if (MACHINE_IS_VM) { | |
162 | ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL); | |
163 | if (!ebc_cmd) | |
164 | return -ENOMEM; | |
165 | len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN); | |
166 | ASCEBC(ebc_cmd, MAX_CMDLEN); | |
167 | EBC_TOUPPER(ebc_cmd, MAX_CMDLEN); | |
168 | ||
169 | /* | |
170 | * It seems to be ok to z/VM to use the init function to | |
646f919e PH |
171 | * retrigger the watchdog. On LPAR WDT_FUNC_CHANGE must |
172 | * be used when the watchdog is running. | |
f7a94db4 PH |
173 | */ |
174 | func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL) | |
175 | : WDT_FUNC_INIT; | |
176 | ||
177 | ret = __diag288_vm(func, dev->timeout, ebc_cmd, len); | |
178 | WARN_ON(ret != 0); | |
179 | kfree(ebc_cmd); | |
b2527d20 | 180 | } else { |
646f919e | 181 | ret = __diag288_lpar(WDT_FUNC_CHANGE, dev->timeout, 0); |
b2527d20 | 182 | } |
646f919e | 183 | |
f7a94db4 PH |
184 | if (ret) |
185 | pr_err("The watchdog timer cannot be started or reset\n"); | |
186 | return ret; | |
187 | } | |
188 | ||
189 | static int wdt_set_timeout(struct watchdog_device * dev, unsigned int new_to) | |
190 | { | |
191 | dev->timeout = new_to; | |
192 | return wdt_ping(dev); | |
193 | } | |
194 | ||
195 | static struct watchdog_ops wdt_ops = { | |
196 | .owner = THIS_MODULE, | |
197 | .start = wdt_start, | |
198 | .stop = wdt_stop, | |
199 | .ping = wdt_ping, | |
200 | .set_timeout = wdt_set_timeout, | |
201 | }; | |
202 | ||
203 | static struct watchdog_info wdt_info = { | |
9ec6cb80 | 204 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
f7a94db4 PH |
205 | .firmware_version = 0, |
206 | .identity = "z Watchdog", | |
207 | }; | |
208 | ||
209 | static struct watchdog_device wdt_dev = { | |
210 | .parent = NULL, | |
211 | .info = &wdt_info, | |
212 | .ops = &wdt_ops, | |
213 | .bootstatus = 0, | |
214 | .timeout = WDT_DEFAULT_TIMEOUT, | |
215 | .min_timeout = MIN_INTERVAL, | |
216 | .max_timeout = MAX_INTERVAL, | |
217 | }; | |
218 | ||
219 | /* | |
220 | * It makes no sense to go into suspend while the watchdog is running. | |
221 | * Depending on the memory size, the watchdog might trigger, while we | |
222 | * are still saving the memory. | |
223 | * We reuse the open flag to ensure that suspend and watchdog open are | |
224 | * exclusive operations | |
225 | */ | |
226 | static int wdt_suspend(void) | |
227 | { | |
228 | if (test_and_set_bit(WDOG_DEV_OPEN, &wdt_dev.status)) { | |
229 | pr_err("Linux cannot be suspended while the watchdog is in use\n"); | |
230 | return notifier_from_errno(-EBUSY); | |
231 | } | |
232 | if (test_bit(WDOG_ACTIVE, &wdt_dev.status)) { | |
233 | clear_bit(WDOG_DEV_OPEN, &wdt_dev.status); | |
234 | pr_err("Linux cannot be suspended while the watchdog is in use\n"); | |
235 | return notifier_from_errno(-EBUSY); | |
236 | } | |
237 | return NOTIFY_DONE; | |
238 | } | |
239 | ||
240 | static int wdt_resume(void) | |
241 | { | |
242 | clear_bit(WDOG_DEV_OPEN, &wdt_dev.status); | |
243 | return NOTIFY_DONE; | |
244 | } | |
245 | ||
246 | static int wdt_power_event(struct notifier_block *this, unsigned long event, | |
247 | void *ptr) | |
248 | { | |
249 | switch (event) { | |
250 | case PM_POST_HIBERNATION: | |
251 | case PM_POST_SUSPEND: | |
252 | return wdt_resume(); | |
253 | case PM_HIBERNATION_PREPARE: | |
254 | case PM_SUSPEND_PREPARE: | |
255 | return wdt_suspend(); | |
256 | default: | |
257 | return NOTIFY_DONE; | |
258 | } | |
259 | } | |
260 | ||
261 | static struct notifier_block wdt_power_notifier = { | |
262 | .notifier_call = wdt_power_event, | |
263 | }; | |
264 | ||
265 | static int __init diag288_init(void) | |
266 | { | |
267 | int ret; | |
268 | char ebc_begin[] = { | |
269 | 194, 197, 199, 201, 213 | |
270 | }; | |
271 | ||
272 | watchdog_set_nowayout(&wdt_dev, nowayout_info); | |
273 | ||
274 | if (MACHINE_IS_VM) { | |
f7a94db4 PH |
275 | if (__diag288_vm(WDT_FUNC_INIT, 15, |
276 | ebc_begin, sizeof(ebc_begin)) != 0) { | |
277 | pr_err("The watchdog cannot be initialized\n"); | |
278 | return -EINVAL; | |
279 | } | |
b2527d20 | 280 | } else { |
646f919e PH |
281 | if (__diag288_lpar(WDT_FUNC_INIT, 30, LPARWDT_RESTART)) { |
282 | pr_err("The watchdog cannot be initialized\n"); | |
283 | return -EINVAL; | |
284 | } | |
f7a94db4 PH |
285 | } |
286 | ||
646f919e | 287 | if (__diag288_lpar(WDT_FUNC_CANCEL, 0, 0)) { |
f7a94db4 PH |
288 | pr_err("The watchdog cannot be deactivated\n"); |
289 | return -EINVAL; | |
290 | } | |
291 | ||
292 | ret = register_pm_notifier(&wdt_power_notifier); | |
293 | if (ret) | |
294 | return ret; | |
295 | ||
296 | ret = watchdog_register_device(&wdt_dev); | |
297 | if (ret) | |
298 | unregister_pm_notifier(&wdt_power_notifier); | |
299 | ||
300 | return ret; | |
301 | } | |
302 | ||
303 | static void __exit diag288_exit(void) | |
304 | { | |
305 | watchdog_unregister_device(&wdt_dev); | |
306 | unregister_pm_notifier(&wdt_power_notifier); | |
307 | } | |
308 | ||
309 | module_init(diag288_init); | |
310 | module_exit(diag288_exit); |