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1/*
2 * Handle extern requests for shutdown, reboot and sysrq
3 */
4
5#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
6
7#include <linux/kernel.h>
8#include <linux/err.h>
9#include <linux/slab.h>
10#include <linux/reboot.h>
11#include <linux/sysrq.h>
12#include <linux/stop_machine.h>
13#include <linux/freezer.h>
14#include <linux/syscore_ops.h>
15#include <linux/export.h>
16
17#include <xen/xen.h>
18#include <xen/xenbus.h>
19#include <xen/grant_table.h>
20#include <xen/events.h>
21#include <xen/hvc-console.h>
22#include <xen/page.h>
23#include <xen/xen-ops.h>
24
25#include <asm/xen/hypercall.h>
26#include <asm/xen/hypervisor.h>
27
28enum shutdown_state {
29 SHUTDOWN_INVALID = -1,
30 SHUTDOWN_POWEROFF = 0,
31 SHUTDOWN_SUSPEND = 2,
32 /* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only
33 report a crash, not be instructed to crash!
34 HALT is the same as POWEROFF, as far as we're concerned. The tools use
35 the distinction when we return the reason code to them. */
36 SHUTDOWN_HALT = 4,
37};
38
39/* Ignore multiple shutdown requests. */
40static enum shutdown_state shutting_down = SHUTDOWN_INVALID;
41
42struct suspend_info {
43 int cancelled;
44};
45
46static RAW_NOTIFIER_HEAD(xen_resume_notifier);
47
48void xen_resume_notifier_register(struct notifier_block *nb)
49{
50 raw_notifier_chain_register(&xen_resume_notifier, nb);
51}
52EXPORT_SYMBOL_GPL(xen_resume_notifier_register);
53
54void xen_resume_notifier_unregister(struct notifier_block *nb)
55{
56 raw_notifier_chain_unregister(&xen_resume_notifier, nb);
57}
58EXPORT_SYMBOL_GPL(xen_resume_notifier_unregister);
59
60#ifdef CONFIG_HIBERNATE_CALLBACKS
61static int xen_suspend(void *data)
62{
63 struct suspend_info *si = data;
64 int err;
65
66 BUG_ON(!irqs_disabled());
67
68 err = syscore_suspend();
69 if (err) {
70 pr_err("%s: system core suspend failed: %d\n", __func__, err);
71 return err;
72 }
73
74 gnttab_suspend();
75 xen_arch_pre_suspend();
76
77 /*
78 * This hypercall returns 1 if suspend was cancelled
79 * or the domain was merely checkpointed, and 0 if it
80 * is resuming in a new domain.
81 */
82 si->cancelled = HYPERVISOR_suspend(xen_pv_domain()
83 ? virt_to_gfn(xen_start_info)
84 : 0);
85
86 xen_arch_post_suspend(si->cancelled);
87 gnttab_resume();
88
89 if (!si->cancelled) {
90 xen_irq_resume();
91 xen_timer_resume();
92 }
93
94 syscore_resume();
95
96 return 0;
97}
98
99static void do_suspend(void)
100{
101 int err;
102 struct suspend_info si;
103
104 shutting_down = SHUTDOWN_SUSPEND;
105
106 err = freeze_processes();
107 if (err) {
108 pr_err("%s: freeze processes failed %d\n", __func__, err);
109 goto out;
110 }
111
112 err = freeze_kernel_threads();
113 if (err) {
114 pr_err("%s: freeze kernel threads failed %d\n", __func__, err);
115 goto out_thaw;
116 }
117
118 err = dpm_suspend_start(PMSG_FREEZE);
119 if (err) {
120 pr_err("%s: dpm_suspend_start %d\n", __func__, err);
121 goto out_thaw;
122 }
123
124 printk(KERN_DEBUG "suspending xenstore...\n");
125 xs_suspend();
126
127 err = dpm_suspend_end(PMSG_FREEZE);
128 if (err) {
129 pr_err("dpm_suspend_end failed: %d\n", err);
130 si.cancelled = 0;
131 goto out_resume;
132 }
133
134 xen_arch_suspend();
135
136 si.cancelled = 1;
137
138 err = stop_machine(xen_suspend, &si, cpumask_of(0));
139
140 /* Resume console as early as possible. */
141 if (!si.cancelled)
142 xen_console_resume();
143
144 raw_notifier_call_chain(&xen_resume_notifier, 0, NULL);
145
146 dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
147
148 if (err) {
149 pr_err("failed to start xen_suspend: %d\n", err);
150 si.cancelled = 1;
151 }
152
153 xen_arch_resume();
154
155out_resume:
156 if (!si.cancelled)
157 xs_resume();
158 else
159 xs_suspend_cancel();
160
161 dpm_resume_end(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
162
163out_thaw:
164 thaw_processes();
165out:
166 shutting_down = SHUTDOWN_INVALID;
167}
168#endif /* CONFIG_HIBERNATE_CALLBACKS */
169
170struct shutdown_handler {
171#define SHUTDOWN_CMD_SIZE 11
172 const char command[SHUTDOWN_CMD_SIZE];
173 bool flag;
174 void (*cb)(void);
175};
176
177static int poweroff_nb(struct notifier_block *cb, unsigned long code, void *unused)
178{
179 switch (code) {
180 case SYS_DOWN:
181 case SYS_HALT:
182 case SYS_POWER_OFF:
183 shutting_down = SHUTDOWN_POWEROFF;
184 default:
185 break;
186 }
187 return NOTIFY_DONE;
188}
189static void do_poweroff(void)
190{
191 switch (system_state) {
192 case SYSTEM_BOOTING:
193 orderly_poweroff(true);
194 break;
195 case SYSTEM_RUNNING:
196 orderly_poweroff(false);
197 break;
198 default:
199 /* Don't do it when we are halting/rebooting. */
200 pr_info("Ignoring Xen toolstack shutdown.\n");
201 break;
202 }
203}
204
205static void do_reboot(void)
206{
207 shutting_down = SHUTDOWN_POWEROFF; /* ? */
208 ctrl_alt_del();
209}
210
211static struct shutdown_handler shutdown_handlers[] = {
212 { "poweroff", true, do_poweroff },
213 { "halt", false, do_poweroff },
214 { "reboot", true, do_reboot },
215#ifdef CONFIG_HIBERNATE_CALLBACKS
216 { "suspend", true, do_suspend },
217#endif
218};
219
220static void shutdown_handler(struct xenbus_watch *watch,
221 const char **vec, unsigned int len)
222{
223 char *str;
224 struct xenbus_transaction xbt;
225 int err;
226 int idx;
227
228 if (shutting_down != SHUTDOWN_INVALID)
229 return;
230
231 again:
232 err = xenbus_transaction_start(&xbt);
233 if (err)
234 return;
235
236 str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
237 /* Ignore read errors and empty reads. */
238 if (XENBUS_IS_ERR_READ(str)) {
239 xenbus_transaction_end(xbt, 1);
240 return;
241 }
242
243 for (idx = 0; idx < ARRAY_SIZE(shutdown_handlers); idx++) {
244 if (strcmp(str, shutdown_handlers[idx].command) == 0)
245 break;
246 }
247
248 /* Only acknowledge commands which we are prepared to handle. */
249 if (idx < ARRAY_SIZE(shutdown_handlers))
250 xenbus_write(xbt, "control", "shutdown", "");
251
252 err = xenbus_transaction_end(xbt, 0);
253 if (err == -EAGAIN) {
254 kfree(str);
255 goto again;
256 }
257
258 if (idx < ARRAY_SIZE(shutdown_handlers)) {
259 shutdown_handlers[idx].cb();
260 } else {
261 pr_info("Ignoring shutdown request: %s\n", str);
262 shutting_down = SHUTDOWN_INVALID;
263 }
264
265 kfree(str);
266}
267
268#ifdef CONFIG_MAGIC_SYSRQ
269static void sysrq_handler(struct xenbus_watch *watch, const char **vec,
270 unsigned int len)
271{
272 char sysrq_key = '\0';
273 struct xenbus_transaction xbt;
274 int err;
275
276 again:
277 err = xenbus_transaction_start(&xbt);
278 if (err)
279 return;
280 if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) {
281 pr_err("Unable to read sysrq code in control/sysrq\n");
282 xenbus_transaction_end(xbt, 1);
283 return;
284 }
285
286 if (sysrq_key != '\0')
287 xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
288
289 err = xenbus_transaction_end(xbt, 0);
290 if (err == -EAGAIN)
291 goto again;
292
293 if (sysrq_key != '\0')
294 handle_sysrq(sysrq_key);
295}
296
297static struct xenbus_watch sysrq_watch = {
298 .node = "control/sysrq",
299 .callback = sysrq_handler
300};
301#endif
302
303static struct xenbus_watch shutdown_watch = {
304 .node = "control/shutdown",
305 .callback = shutdown_handler
306};
307
308static struct notifier_block xen_reboot_nb = {
309 .notifier_call = poweroff_nb,
310};
311
312static int setup_shutdown_watcher(void)
313{
314 int err;
315 int idx;
316#define FEATURE_PATH_SIZE (SHUTDOWN_CMD_SIZE + sizeof("feature-"))
317 char node[FEATURE_PATH_SIZE];
318
319 err = register_xenbus_watch(&shutdown_watch);
320 if (err) {
321 pr_err("Failed to set shutdown watcher\n");
322 return err;
323 }
324
325
326#ifdef CONFIG_MAGIC_SYSRQ
327 err = register_xenbus_watch(&sysrq_watch);
328 if (err) {
329 pr_err("Failed to set sysrq watcher\n");
330 return err;
331 }
332#endif
333
334 for (idx = 0; idx < ARRAY_SIZE(shutdown_handlers); idx++) {
335 if (!shutdown_handlers[idx].flag)
336 continue;
337 snprintf(node, FEATURE_PATH_SIZE, "feature-%s",
338 shutdown_handlers[idx].command);
339 xenbus_printf(XBT_NIL, "control", node, "%u", 1);
340 }
341
342 return 0;
343}
344
345static int shutdown_event(struct notifier_block *notifier,
346 unsigned long event,
347 void *data)
348{
349 setup_shutdown_watcher();
350 return NOTIFY_DONE;
351}
352
353int xen_setup_shutdown_event(void)
354{
355 static struct notifier_block xenstore_notifier = {
356 .notifier_call = shutdown_event
357 };
358
359 if (!xen_domain())
360 return -ENODEV;
361 register_xenstore_notifier(&xenstore_notifier);
362 register_reboot_notifier(&xen_reboot_nb);
363
364 return 0;
365}
366EXPORT_SYMBOL_GPL(xen_setup_shutdown_event);
367
368subsys_initcall(xen_setup_shutdown_event);
1/*
2 * Handle extern requests for shutdown, reboot and sysrq
3 */
4
5#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
6
7#include <linux/kernel.h>
8#include <linux/err.h>
9#include <linux/slab.h>
10#include <linux/reboot.h>
11#include <linux/sysrq.h>
12#include <linux/stop_machine.h>
13#include <linux/freezer.h>
14#include <linux/syscore_ops.h>
15#include <linux/export.h>
16
17#include <xen/xen.h>
18#include <xen/xenbus.h>
19#include <xen/grant_table.h>
20#include <xen/events.h>
21#include <xen/hvc-console.h>
22#include <xen/page.h>
23#include <xen/xen-ops.h>
24
25#include <asm/xen/hypercall.h>
26#include <asm/xen/hypervisor.h>
27
28enum shutdown_state {
29 SHUTDOWN_INVALID = -1,
30 SHUTDOWN_POWEROFF = 0,
31 SHUTDOWN_SUSPEND = 2,
32 /* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only
33 report a crash, not be instructed to crash!
34 HALT is the same as POWEROFF, as far as we're concerned. The tools use
35 the distinction when we return the reason code to them. */
36 SHUTDOWN_HALT = 4,
37};
38
39/* Ignore multiple shutdown requests. */
40static enum shutdown_state shutting_down = SHUTDOWN_INVALID;
41
42struct suspend_info {
43 int cancelled;
44};
45
46static RAW_NOTIFIER_HEAD(xen_resume_notifier);
47
48void xen_resume_notifier_register(struct notifier_block *nb)
49{
50 raw_notifier_chain_register(&xen_resume_notifier, nb);
51}
52EXPORT_SYMBOL_GPL(xen_resume_notifier_register);
53
54void xen_resume_notifier_unregister(struct notifier_block *nb)
55{
56 raw_notifier_chain_unregister(&xen_resume_notifier, nb);
57}
58EXPORT_SYMBOL_GPL(xen_resume_notifier_unregister);
59
60#ifdef CONFIG_HIBERNATE_CALLBACKS
61static int xen_suspend(void *data)
62{
63 struct suspend_info *si = data;
64 int err;
65
66 BUG_ON(!irqs_disabled());
67
68 err = syscore_suspend();
69 if (err) {
70 pr_err("%s: system core suspend failed: %d\n", __func__, err);
71 return err;
72 }
73
74 gnttab_suspend();
75 xen_manage_runstate_time(-1);
76 xen_arch_pre_suspend();
77
78 si->cancelled = HYPERVISOR_suspend(xen_pv_domain()
79 ? virt_to_gfn(xen_start_info)
80 : 0);
81
82 xen_arch_post_suspend(si->cancelled);
83 xen_manage_runstate_time(si->cancelled ? 1 : 0);
84 gnttab_resume();
85
86 if (!si->cancelled) {
87 xen_irq_resume();
88 xen_timer_resume();
89 }
90
91 syscore_resume();
92
93 return 0;
94}
95
96static void do_suspend(void)
97{
98 int err;
99 struct suspend_info si;
100
101 shutting_down = SHUTDOWN_SUSPEND;
102
103 err = freeze_processes();
104 if (err) {
105 pr_err("%s: freeze processes failed %d\n", __func__, err);
106 goto out;
107 }
108
109 err = freeze_kernel_threads();
110 if (err) {
111 pr_err("%s: freeze kernel threads failed %d\n", __func__, err);
112 goto out_thaw;
113 }
114
115 err = dpm_suspend_start(PMSG_FREEZE);
116 if (err) {
117 pr_err("%s: dpm_suspend_start %d\n", __func__, err);
118 goto out_thaw;
119 }
120
121 printk(KERN_DEBUG "suspending xenstore...\n");
122 xs_suspend();
123
124 err = dpm_suspend_end(PMSG_FREEZE);
125 if (err) {
126 pr_err("dpm_suspend_end failed: %d\n", err);
127 si.cancelled = 0;
128 goto out_resume;
129 }
130
131 xen_arch_suspend();
132
133 si.cancelled = 1;
134
135 err = stop_machine(xen_suspend, &si, cpumask_of(0));
136
137 /* Resume console as early as possible. */
138 if (!si.cancelled)
139 xen_console_resume();
140
141 raw_notifier_call_chain(&xen_resume_notifier, 0, NULL);
142
143 dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
144
145 if (err) {
146 pr_err("failed to start xen_suspend: %d\n", err);
147 si.cancelled = 1;
148 }
149
150 xen_arch_resume();
151
152out_resume:
153 if (!si.cancelled)
154 xs_resume();
155 else
156 xs_suspend_cancel();
157
158 dpm_resume_end(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
159
160out_thaw:
161 thaw_processes();
162out:
163 shutting_down = SHUTDOWN_INVALID;
164}
165#endif /* CONFIG_HIBERNATE_CALLBACKS */
166
167struct shutdown_handler {
168#define SHUTDOWN_CMD_SIZE 11
169 const char command[SHUTDOWN_CMD_SIZE];
170 bool flag;
171 void (*cb)(void);
172};
173
174static int poweroff_nb(struct notifier_block *cb, unsigned long code, void *unused)
175{
176 switch (code) {
177 case SYS_DOWN:
178 case SYS_HALT:
179 case SYS_POWER_OFF:
180 shutting_down = SHUTDOWN_POWEROFF;
181 default:
182 break;
183 }
184 return NOTIFY_DONE;
185}
186static void do_poweroff(void)
187{
188 switch (system_state) {
189 case SYSTEM_BOOTING:
190 case SYSTEM_SCHEDULING:
191 orderly_poweroff(true);
192 break;
193 case SYSTEM_RUNNING:
194 orderly_poweroff(false);
195 break;
196 default:
197 /* Don't do it when we are halting/rebooting. */
198 pr_info("Ignoring Xen toolstack shutdown.\n");
199 break;
200 }
201}
202
203static void do_reboot(void)
204{
205 shutting_down = SHUTDOWN_POWEROFF; /* ? */
206 ctrl_alt_del();
207}
208
209static struct shutdown_handler shutdown_handlers[] = {
210 { "poweroff", true, do_poweroff },
211 { "halt", false, do_poweroff },
212 { "reboot", true, do_reboot },
213#ifdef CONFIG_HIBERNATE_CALLBACKS
214 { "suspend", true, do_suspend },
215#endif
216};
217
218static void shutdown_handler(struct xenbus_watch *watch,
219 const char *path, const char *token)
220{
221 char *str;
222 struct xenbus_transaction xbt;
223 int err;
224 int idx;
225
226 if (shutting_down != SHUTDOWN_INVALID)
227 return;
228
229 again:
230 err = xenbus_transaction_start(&xbt);
231 if (err)
232 return;
233
234 str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
235 /* Ignore read errors and empty reads. */
236 if (XENBUS_IS_ERR_READ(str)) {
237 xenbus_transaction_end(xbt, 1);
238 return;
239 }
240
241 for (idx = 0; idx < ARRAY_SIZE(shutdown_handlers); idx++) {
242 if (strcmp(str, shutdown_handlers[idx].command) == 0)
243 break;
244 }
245
246 /* Only acknowledge commands which we are prepared to handle. */
247 if (idx < ARRAY_SIZE(shutdown_handlers))
248 xenbus_write(xbt, "control", "shutdown", "");
249
250 err = xenbus_transaction_end(xbt, 0);
251 if (err == -EAGAIN) {
252 kfree(str);
253 goto again;
254 }
255
256 if (idx < ARRAY_SIZE(shutdown_handlers)) {
257 shutdown_handlers[idx].cb();
258 } else {
259 pr_info("Ignoring shutdown request: %s\n", str);
260 shutting_down = SHUTDOWN_INVALID;
261 }
262
263 kfree(str);
264}
265
266#ifdef CONFIG_MAGIC_SYSRQ
267static void sysrq_handler(struct xenbus_watch *watch, const char *path,
268 const char *token)
269{
270 char sysrq_key = '\0';
271 struct xenbus_transaction xbt;
272 int err;
273
274 again:
275 err = xenbus_transaction_start(&xbt);
276 if (err)
277 return;
278 err = xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key);
279 if (err < 0) {
280 /*
281 * The Xenstore watch fires directly after registering it and
282 * after a suspend/resume cycle. So ENOENT is no error but
283 * might happen in those cases.
284 */
285 if (err != -ENOENT)
286 pr_err("Error %d reading sysrq code in control/sysrq\n",
287 err);
288 xenbus_transaction_end(xbt, 1);
289 return;
290 }
291
292 if (sysrq_key != '\0')
293 xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
294
295 err = xenbus_transaction_end(xbt, 0);
296 if (err == -EAGAIN)
297 goto again;
298
299 if (sysrq_key != '\0')
300 handle_sysrq(sysrq_key);
301}
302
303static struct xenbus_watch sysrq_watch = {
304 .node = "control/sysrq",
305 .callback = sysrq_handler
306};
307#endif
308
309static struct xenbus_watch shutdown_watch = {
310 .node = "control/shutdown",
311 .callback = shutdown_handler
312};
313
314static struct notifier_block xen_reboot_nb = {
315 .notifier_call = poweroff_nb,
316};
317
318static int setup_shutdown_watcher(void)
319{
320 int err;
321 int idx;
322#define FEATURE_PATH_SIZE (SHUTDOWN_CMD_SIZE + sizeof("feature-"))
323 char node[FEATURE_PATH_SIZE];
324
325 err = register_xenbus_watch(&shutdown_watch);
326 if (err) {
327 pr_err("Failed to set shutdown watcher\n");
328 return err;
329 }
330
331
332#ifdef CONFIG_MAGIC_SYSRQ
333 err = register_xenbus_watch(&sysrq_watch);
334 if (err) {
335 pr_err("Failed to set sysrq watcher\n");
336 return err;
337 }
338#endif
339
340 for (idx = 0; idx < ARRAY_SIZE(shutdown_handlers); idx++) {
341 if (!shutdown_handlers[idx].flag)
342 continue;
343 snprintf(node, FEATURE_PATH_SIZE, "feature-%s",
344 shutdown_handlers[idx].command);
345 xenbus_printf(XBT_NIL, "control", node, "%u", 1);
346 }
347
348 return 0;
349}
350
351static int shutdown_event(struct notifier_block *notifier,
352 unsigned long event,
353 void *data)
354{
355 setup_shutdown_watcher();
356 return NOTIFY_DONE;
357}
358
359int xen_setup_shutdown_event(void)
360{
361 static struct notifier_block xenstore_notifier = {
362 .notifier_call = shutdown_event
363 };
364
365 if (!xen_domain())
366 return -ENODEV;
367 register_xenstore_notifier(&xenstore_notifier);
368 register_reboot_notifier(&xen_reboot_nb);
369
370 return 0;
371}
372EXPORT_SYMBOL_GPL(xen_setup_shutdown_event);
373
374subsys_initcall(xen_setup_shutdown_event);