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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Watchdog driver for z/VM and LPAR using the diag 288 interface.
4 *
5 * Under z/VM, expiration of the watchdog will send a "system restart" command
6 * to CP.
7 *
8 * The command can be altered using the module parameter "cmd". This is
9 * not recommended because it's only supported on z/VM but not whith LPAR.
10 *
11 * On LPAR, the watchdog will always trigger a system restart. the module
12 * paramter cmd is meaningless here.
13 *
14 *
15 * Copyright IBM Corp. 2004, 2013
16 * Author(s): Arnd Bergmann (arndb@de.ibm.com)
17 * Philipp Hachtmann (phacht@de.ibm.com)
18 *
19 */
20
21#define KMSG_COMPONENT "diag288_wdt"
22#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
23
24#include <linux/init.h>
25#include <linux/kernel.h>
26#include <linux/module.h>
27#include <linux/moduleparam.h>
28#include <linux/slab.h>
29#include <linux/watchdog.h>
30#include <asm/ebcdic.h>
31#include <asm/diag.h>
32#include <linux/io.h>
33
34#define MAX_CMDLEN 240
35#define DEFAULT_CMD "SYSTEM RESTART"
36
37#define MIN_INTERVAL 15 /* Minimal time supported by diag88 */
38#define MAX_INTERVAL 3600 /* One hour should be enough - pure estimation */
39
40#define WDT_DEFAULT_TIMEOUT 30
41
42/* Function codes - init, change, cancel */
43#define WDT_FUNC_INIT 0
44#define WDT_FUNC_CHANGE 1
45#define WDT_FUNC_CANCEL 2
46#define WDT_FUNC_CONCEAL 0x80000000
47
48/* Action codes for LPAR watchdog */
49#define LPARWDT_RESTART 0
50
51static char wdt_cmd[MAX_CMDLEN] = DEFAULT_CMD;
52static bool conceal_on;
53static bool nowayout_info = WATCHDOG_NOWAYOUT;
54
55MODULE_LICENSE("GPL");
56MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
57MODULE_AUTHOR("Philipp Hachtmann <phacht@de.ibm.com>");
58
59MODULE_DESCRIPTION("System z diag288 Watchdog Timer");
60
61module_param_string(cmd, wdt_cmd, MAX_CMDLEN, 0644);
62MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers (z/VM only)");
63
64module_param_named(conceal, conceal_on, bool, 0644);
65MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog is active (z/VM only)");
66
67module_param_named(nowayout, nowayout_info, bool, 0444);
68MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = CONFIG_WATCHDOG_NOWAYOUT)");
69
70MODULE_ALIAS("vmwatchdog");
71
72static char *cmd_buf;
73
74static int diag288(unsigned int func, unsigned int timeout,
75 unsigned long action, unsigned int len)
76{
77 union register_pair r1 = { .even = func, .odd = timeout, };
78 union register_pair r3 = { .even = action, .odd = len, };
79 int err;
80
81 diag_stat_inc(DIAG_STAT_X288);
82
83 err = -EINVAL;
84 asm volatile(
85 " diag %[r1],%[r3],0x288\n"
86 "0: la %[err],0\n"
87 "1:\n"
88 EX_TABLE(0b, 1b)
89 : [err] "+d" (err)
90 : [r1] "d" (r1.pair), [r3] "d" (r3.pair)
91 : "cc", "memory");
92 return err;
93}
94
95static int diag288_str(unsigned int func, unsigned int timeout, char *cmd)
96{
97 ssize_t len;
98
99 len = strscpy(cmd_buf, cmd, MAX_CMDLEN);
100 if (len < 0)
101 return len;
102 ASCEBC(cmd_buf, MAX_CMDLEN);
103 EBC_TOUPPER(cmd_buf, MAX_CMDLEN);
104
105 return diag288(func, timeout, virt_to_phys(cmd_buf), len);
106}
107
108static int wdt_start(struct watchdog_device *dev)
109{
110 int ret;
111 unsigned int func;
112
113 if (MACHINE_IS_VM) {
114 func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL)
115 : WDT_FUNC_INIT;
116 ret = diag288_str(func, dev->timeout, wdt_cmd);
117 WARN_ON(ret != 0);
118 } else {
119 ret = diag288(WDT_FUNC_INIT, dev->timeout, LPARWDT_RESTART, 0);
120 }
121
122 if (ret) {
123 pr_err("The watchdog cannot be activated\n");
124 return ret;
125 }
126 return 0;
127}
128
129static int wdt_stop(struct watchdog_device *dev)
130{
131 return diag288(WDT_FUNC_CANCEL, 0, 0, 0);
132}
133
134static int wdt_ping(struct watchdog_device *dev)
135{
136 int ret;
137 unsigned int func;
138
139 if (MACHINE_IS_VM) {
140 /*
141 * It seems to be ok to z/VM to use the init function to
142 * retrigger the watchdog. On LPAR WDT_FUNC_CHANGE must
143 * be used when the watchdog is running.
144 */
145 func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL)
146 : WDT_FUNC_INIT;
147
148 ret = diag288_str(func, dev->timeout, wdt_cmd);
149 WARN_ON(ret != 0);
150 } else {
151 ret = diag288(WDT_FUNC_CHANGE, dev->timeout, 0, 0);
152 }
153
154 if (ret)
155 pr_err("The watchdog timer cannot be started or reset\n");
156 return ret;
157}
158
159static int wdt_set_timeout(struct watchdog_device * dev, unsigned int new_to)
160{
161 dev->timeout = new_to;
162 return wdt_ping(dev);
163}
164
165static const struct watchdog_ops wdt_ops = {
166 .owner = THIS_MODULE,
167 .start = wdt_start,
168 .stop = wdt_stop,
169 .ping = wdt_ping,
170 .set_timeout = wdt_set_timeout,
171};
172
173static const struct watchdog_info wdt_info = {
174 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
175 .firmware_version = 0,
176 .identity = "z Watchdog",
177};
178
179static struct watchdog_device wdt_dev = {
180 .parent = NULL,
181 .info = &wdt_info,
182 .ops = &wdt_ops,
183 .bootstatus = 0,
184 .timeout = WDT_DEFAULT_TIMEOUT,
185 .min_timeout = MIN_INTERVAL,
186 .max_timeout = MAX_INTERVAL,
187};
188
189static int __init diag288_init(void)
190{
191 int ret;
192
193 watchdog_set_nowayout(&wdt_dev, nowayout_info);
194
195 if (MACHINE_IS_VM) {
196 cmd_buf = kmalloc(MAX_CMDLEN, GFP_KERNEL);
197 if (!cmd_buf) {
198 pr_err("The watchdog cannot be initialized\n");
199 return -ENOMEM;
200 }
201
202 ret = diag288_str(WDT_FUNC_INIT, MIN_INTERVAL, "BEGIN");
203 if (ret != 0) {
204 pr_err("The watchdog cannot be initialized\n");
205 kfree(cmd_buf);
206 return -EINVAL;
207 }
208 } else {
209 if (diag288(WDT_FUNC_INIT, WDT_DEFAULT_TIMEOUT,
210 LPARWDT_RESTART, 0)) {
211 pr_err("The watchdog cannot be initialized\n");
212 return -EINVAL;
213 }
214 }
215
216 if (diag288(WDT_FUNC_CANCEL, 0, 0, 0)) {
217 pr_err("The watchdog cannot be deactivated\n");
218 return -EINVAL;
219 }
220
221 return watchdog_register_device(&wdt_dev);
222}
223
224static void __exit diag288_exit(void)
225{
226 watchdog_unregister_device(&wdt_dev);
227 kfree(cmd_buf);
228}
229
230module_init(diag288_init);
231module_exit(diag288_exit);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Watchdog driver for z/VM and LPAR using the diag 288 interface.
4 *
5 * Under z/VM, expiration of the watchdog will send a "system restart" command
6 * to CP.
7 *
8 * The command can be altered using the module parameter "cmd". This is
9 * not recommended because it's only supported on z/VM but not whith LPAR.
10 *
11 * On LPAR, the watchdog will always trigger a system restart. the module
12 * paramter cmd is meaningless here.
13 *
14 *
15 * Copyright IBM Corp. 2004, 2013
16 * Author(s): Arnd Bergmann (arndb@de.ibm.com)
17 * Philipp Hachtmann (phacht@de.ibm.com)
18 *
19 */
20
21#define KMSG_COMPONENT "diag288_wdt"
22#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
23
24#include <linux/init.h>
25#include <linux/kernel.h>
26#include <linux/module.h>
27#include <linux/moduleparam.h>
28#include <linux/slab.h>
29#include <linux/watchdog.h>
30#include <linux/suspend.h>
31#include <asm/ebcdic.h>
32#include <asm/diag.h>
33#include <linux/io.h>
34
35#define MAX_CMDLEN 240
36#define DEFAULT_CMD "SYSTEM RESTART"
37
38#define MIN_INTERVAL 15 /* Minimal time supported by diag88 */
39#define MAX_INTERVAL 3600 /* One hour should be enough - pure estimation */
40
41#define WDT_DEFAULT_TIMEOUT 30
42
43/* Function codes - init, change, cancel */
44#define WDT_FUNC_INIT 0
45#define WDT_FUNC_CHANGE 1
46#define WDT_FUNC_CANCEL 2
47#define WDT_FUNC_CONCEAL 0x80000000
48
49/* Action codes for LPAR watchdog */
50#define LPARWDT_RESTART 0
51
52static char wdt_cmd[MAX_CMDLEN] = DEFAULT_CMD;
53static bool conceal_on;
54static bool nowayout_info = WATCHDOG_NOWAYOUT;
55
56MODULE_LICENSE("GPL");
57MODULE_AUTHOR("Arnd Bergmann <arndb@de.ibm.com>");
58MODULE_AUTHOR("Philipp Hachtmann <phacht@de.ibm.com>");
59
60MODULE_DESCRIPTION("System z diag288 Watchdog Timer");
61
62module_param_string(cmd, wdt_cmd, MAX_CMDLEN, 0644);
63MODULE_PARM_DESC(cmd, "CP command that is run when the watchdog triggers (z/VM only)");
64
65module_param_named(conceal, conceal_on, bool, 0644);
66MODULE_PARM_DESC(conceal, "Enable the CONCEAL CP option while the watchdog is active (z/VM only)");
67
68module_param_named(nowayout, nowayout_info, bool, 0444);
69MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default = CONFIG_WATCHDOG_NOWAYOUT)");
70
71MODULE_ALIAS("vmwatchdog");
72
73static int __diag288(unsigned int func, unsigned int timeout,
74 unsigned long action, unsigned int len)
75{
76 register unsigned long __func asm("2") = func;
77 register unsigned long __timeout asm("3") = timeout;
78 register unsigned long __action asm("4") = action;
79 register unsigned long __len asm("5") = len;
80 int err;
81
82 err = -EINVAL;
83 asm volatile(
84 " diag %1, %3, 0x288\n"
85 "0: la %0, 0\n"
86 "1:\n"
87 EX_TABLE(0b, 1b)
88 : "+d" (err) : "d"(__func), "d"(__timeout),
89 "d"(__action), "d"(__len) : "1", "cc");
90 return err;
91}
92
93static int __diag288_vm(unsigned int func, unsigned int timeout,
94 char *cmd, size_t len)
95{
96 diag_stat_inc(DIAG_STAT_X288);
97 return __diag288(func, timeout, virt_to_phys(cmd), len);
98}
99
100static int __diag288_lpar(unsigned int func, unsigned int timeout,
101 unsigned long action)
102{
103 diag_stat_inc(DIAG_STAT_X288);
104 return __diag288(func, timeout, action, 0);
105}
106
107static unsigned long wdt_status;
108
109#define DIAG_WDOG_BUSY 0
110
111static int wdt_start(struct watchdog_device *dev)
112{
113 char *ebc_cmd;
114 size_t len;
115 int ret;
116 unsigned int func;
117
118 if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_status))
119 return -EBUSY;
120
121 if (MACHINE_IS_VM) {
122 ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
123 if (!ebc_cmd) {
124 clear_bit(DIAG_WDOG_BUSY, &wdt_status);
125 return -ENOMEM;
126 }
127 len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
128 ASCEBC(ebc_cmd, MAX_CMDLEN);
129 EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
130
131 func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL)
132 : WDT_FUNC_INIT;
133 ret = __diag288_vm(func, dev->timeout, ebc_cmd, len);
134 WARN_ON(ret != 0);
135 kfree(ebc_cmd);
136 } else {
137 ret = __diag288_lpar(WDT_FUNC_INIT,
138 dev->timeout, LPARWDT_RESTART);
139 }
140
141 if (ret) {
142 pr_err("The watchdog cannot be activated\n");
143 clear_bit(DIAG_WDOG_BUSY, &wdt_status);
144 return ret;
145 }
146 return 0;
147}
148
149static int wdt_stop(struct watchdog_device *dev)
150{
151 int ret;
152
153 diag_stat_inc(DIAG_STAT_X288);
154 ret = __diag288(WDT_FUNC_CANCEL, 0, 0, 0);
155
156 clear_bit(DIAG_WDOG_BUSY, &wdt_status);
157
158 return ret;
159}
160
161static int wdt_ping(struct watchdog_device *dev)
162{
163 char *ebc_cmd;
164 size_t len;
165 int ret;
166 unsigned int func;
167
168 if (MACHINE_IS_VM) {
169 ebc_cmd = kmalloc(MAX_CMDLEN, GFP_KERNEL);
170 if (!ebc_cmd)
171 return -ENOMEM;
172 len = strlcpy(ebc_cmd, wdt_cmd, MAX_CMDLEN);
173 ASCEBC(ebc_cmd, MAX_CMDLEN);
174 EBC_TOUPPER(ebc_cmd, MAX_CMDLEN);
175
176 /*
177 * It seems to be ok to z/VM to use the init function to
178 * retrigger the watchdog. On LPAR WDT_FUNC_CHANGE must
179 * be used when the watchdog is running.
180 */
181 func = conceal_on ? (WDT_FUNC_INIT | WDT_FUNC_CONCEAL)
182 : WDT_FUNC_INIT;
183
184 ret = __diag288_vm(func, dev->timeout, ebc_cmd, len);
185 WARN_ON(ret != 0);
186 kfree(ebc_cmd);
187 } else {
188 ret = __diag288_lpar(WDT_FUNC_CHANGE, dev->timeout, 0);
189 }
190
191 if (ret)
192 pr_err("The watchdog timer cannot be started or reset\n");
193 return ret;
194}
195
196static int wdt_set_timeout(struct watchdog_device * dev, unsigned int new_to)
197{
198 dev->timeout = new_to;
199 return wdt_ping(dev);
200}
201
202static const struct watchdog_ops wdt_ops = {
203 .owner = THIS_MODULE,
204 .start = wdt_start,
205 .stop = wdt_stop,
206 .ping = wdt_ping,
207 .set_timeout = wdt_set_timeout,
208};
209
210static const struct watchdog_info wdt_info = {
211 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
212 .firmware_version = 0,
213 .identity = "z Watchdog",
214};
215
216static struct watchdog_device wdt_dev = {
217 .parent = NULL,
218 .info = &wdt_info,
219 .ops = &wdt_ops,
220 .bootstatus = 0,
221 .timeout = WDT_DEFAULT_TIMEOUT,
222 .min_timeout = MIN_INTERVAL,
223 .max_timeout = MAX_INTERVAL,
224};
225
226/*
227 * It makes no sense to go into suspend while the watchdog is running.
228 * Depending on the memory size, the watchdog might trigger, while we
229 * are still saving the memory.
230 */
231static int wdt_suspend(void)
232{
233 if (test_and_set_bit(DIAG_WDOG_BUSY, &wdt_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
240static int wdt_resume(void)
241{
242 clear_bit(DIAG_WDOG_BUSY, &wdt_status);
243 return NOTIFY_DONE;
244}
245
246static 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
261static struct notifier_block wdt_power_notifier = {
262 .notifier_call = wdt_power_event,
263};
264
265static 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) {
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 }
280 } else {
281 if (__diag288_lpar(WDT_FUNC_INIT, 30, LPARWDT_RESTART)) {
282 pr_err("The watchdog cannot be initialized\n");
283 return -EINVAL;
284 }
285 }
286
287 if (__diag288_lpar(WDT_FUNC_CANCEL, 0, 0)) {
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
303static void __exit diag288_exit(void)
304{
305 watchdog_unregister_device(&wdt_dev);
306 unregister_pm_notifier(&wdt_power_notifier);
307}
308
309module_init(diag288_init);
310module_exit(diag288_exit);