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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_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);
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/xen-ops.h>
23
24#include <asm/xen/hypercall.h>
25#include <asm/xen/page.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 unsigned long arg; /* extra hypercall argument */
45 void (*pre)(void);
46 void (*post)(int cancelled);
47};
48
49static RAW_NOTIFIER_HEAD(xen_resume_notifier);
50
51void xen_resume_notifier_register(struct notifier_block *nb)
52{
53 raw_notifier_chain_register(&xen_resume_notifier, nb);
54}
55EXPORT_SYMBOL_GPL(xen_resume_notifier_register);
56
57void xen_resume_notifier_unregister(struct notifier_block *nb)
58{
59 raw_notifier_chain_unregister(&xen_resume_notifier, nb);
60}
61EXPORT_SYMBOL_GPL(xen_resume_notifier_unregister);
62
63#ifdef CONFIG_HIBERNATE_CALLBACKS
64static void xen_hvm_post_suspend(int cancelled)
65{
66 xen_arch_hvm_post_suspend(cancelled);
67 gnttab_resume();
68}
69
70static void xen_pre_suspend(void)
71{
72 xen_mm_pin_all();
73 gnttab_suspend();
74 xen_arch_pre_suspend();
75}
76
77static void xen_post_suspend(int cancelled)
78{
79 xen_arch_post_suspend(cancelled);
80 gnttab_resume();
81 xen_mm_unpin_all();
82}
83
84static int xen_suspend(void *data)
85{
86 struct suspend_info *si = data;
87 int err;
88
89 BUG_ON(!irqs_disabled());
90
91 err = syscore_suspend();
92 if (err) {
93 pr_err("%s: system core suspend failed: %d\n", __func__, err);
94 return err;
95 }
96
97 if (si->pre)
98 si->pre();
99
100 /*
101 * This hypercall returns 1 if suspend was cancelled
102 * or the domain was merely checkpointed, and 0 if it
103 * is resuming in a new domain.
104 */
105 si->cancelled = HYPERVISOR_suspend(si->arg);
106
107 if (si->post)
108 si->post(si->cancelled);
109
110 if (!si->cancelled) {
111 xen_irq_resume();
112 xen_console_resume();
113 xen_timer_resume();
114 }
115
116 syscore_resume();
117
118 return 0;
119}
120
121static void do_suspend(void)
122{
123 int err;
124 struct suspend_info si;
125
126 shutting_down = SHUTDOWN_SUSPEND;
127
128#ifdef CONFIG_PREEMPT
129 /* If the kernel is preemptible, we need to freeze all the processes
130 to prevent them from being in the middle of a pagetable update
131 during suspend. */
132 err = freeze_processes();
133 if (err) {
134 pr_err("%s: freeze failed %d\n", __func__, err);
135 goto out;
136 }
137#endif
138
139 err = dpm_suspend_start(PMSG_FREEZE);
140 if (err) {
141 pr_err("%s: dpm_suspend_start %d\n", __func__, err);
142 goto out_thaw;
143 }
144
145 printk(KERN_DEBUG "suspending xenstore...\n");
146 xs_suspend();
147
148 err = dpm_suspend_end(PMSG_FREEZE);
149 if (err) {
150 pr_err("dpm_suspend_end failed: %d\n", err);
151 si.cancelled = 0;
152 goto out_resume;
153 }
154
155 si.cancelled = 1;
156
157 if (xen_hvm_domain()) {
158 si.arg = 0UL;
159 si.pre = NULL;
160 si.post = &xen_hvm_post_suspend;
161 } else {
162 si.arg = virt_to_mfn(xen_start_info);
163 si.pre = &xen_pre_suspend;
164 si.post = &xen_post_suspend;
165 }
166
167 err = stop_machine(xen_suspend, &si, cpumask_of(0));
168
169 raw_notifier_call_chain(&xen_resume_notifier, 0, NULL);
170
171 dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
172
173 if (err) {
174 pr_err("failed to start xen_suspend: %d\n", err);
175 si.cancelled = 1;
176 }
177
178out_resume:
179 if (!si.cancelled) {
180 xen_arch_resume();
181 xs_resume();
182 } else
183 xs_suspend_cancel();
184
185 dpm_resume_end(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
186
187out_thaw:
188#ifdef CONFIG_PREEMPT
189 thaw_processes();
190out:
191#endif
192 shutting_down = SHUTDOWN_INVALID;
193}
194#endif /* CONFIG_HIBERNATE_CALLBACKS */
195
196struct shutdown_handler {
197 const char *command;
198 void (*cb)(void);
199};
200
201static int poweroff_nb(struct notifier_block *cb, unsigned long code, void *unused)
202{
203 switch (code) {
204 case SYS_DOWN:
205 case SYS_HALT:
206 case SYS_POWER_OFF:
207 shutting_down = SHUTDOWN_POWEROFF;
208 default:
209 break;
210 }
211 return NOTIFY_DONE;
212}
213static void do_poweroff(void)
214{
215 switch (system_state) {
216 case SYSTEM_BOOTING:
217 orderly_poweroff(true);
218 break;
219 case SYSTEM_RUNNING:
220 orderly_poweroff(false);
221 break;
222 default:
223 /* Don't do it when we are halting/rebooting. */
224 pr_info("Ignoring Xen toolstack shutdown.\n");
225 break;
226 }
227}
228
229static void do_reboot(void)
230{
231 shutting_down = SHUTDOWN_POWEROFF; /* ? */
232 ctrl_alt_del();
233}
234
235static void shutdown_handler(struct xenbus_watch *watch,
236 const char **vec, unsigned int len)
237{
238 char *str;
239 struct xenbus_transaction xbt;
240 int err;
241 static struct shutdown_handler handlers[] = {
242 { "poweroff", do_poweroff },
243 { "halt", do_poweroff },
244 { "reboot", do_reboot },
245#ifdef CONFIG_HIBERNATE_CALLBACKS
246 { "suspend", do_suspend },
247#endif
248 {NULL, NULL},
249 };
250 static struct shutdown_handler *handler;
251
252 if (shutting_down != SHUTDOWN_INVALID)
253 return;
254
255 again:
256 err = xenbus_transaction_start(&xbt);
257 if (err)
258 return;
259
260 str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
261 /* Ignore read errors and empty reads. */
262 if (XENBUS_IS_ERR_READ(str)) {
263 xenbus_transaction_end(xbt, 1);
264 return;
265 }
266
267 for (handler = &handlers[0]; handler->command; handler++) {
268 if (strcmp(str, handler->command) == 0)
269 break;
270 }
271
272 /* Only acknowledge commands which we are prepared to handle. */
273 if (handler->cb)
274 xenbus_write(xbt, "control", "shutdown", "");
275
276 err = xenbus_transaction_end(xbt, 0);
277 if (err == -EAGAIN) {
278 kfree(str);
279 goto again;
280 }
281
282 if (handler->cb) {
283 handler->cb();
284 } else {
285 pr_info("Ignoring shutdown request: %s\n", str);
286 shutting_down = SHUTDOWN_INVALID;
287 }
288
289 kfree(str);
290}
291
292#ifdef CONFIG_MAGIC_SYSRQ
293static void sysrq_handler(struct xenbus_watch *watch, const char **vec,
294 unsigned int len)
295{
296 char sysrq_key = '\0';
297 struct xenbus_transaction xbt;
298 int err;
299
300 again:
301 err = xenbus_transaction_start(&xbt);
302 if (err)
303 return;
304 if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) {
305 pr_err("Unable to read sysrq code in control/sysrq\n");
306 xenbus_transaction_end(xbt, 1);
307 return;
308 }
309
310 if (sysrq_key != '\0')
311 xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
312
313 err = xenbus_transaction_end(xbt, 0);
314 if (err == -EAGAIN)
315 goto again;
316
317 if (sysrq_key != '\0')
318 handle_sysrq(sysrq_key);
319}
320
321static struct xenbus_watch sysrq_watch = {
322 .node = "control/sysrq",
323 .callback = sysrq_handler
324};
325#endif
326
327static struct xenbus_watch shutdown_watch = {
328 .node = "control/shutdown",
329 .callback = shutdown_handler
330};
331
332static struct notifier_block xen_reboot_nb = {
333 .notifier_call = poweroff_nb,
334};
335
336static int setup_shutdown_watcher(void)
337{
338 int err;
339
340 err = register_xenbus_watch(&shutdown_watch);
341 if (err) {
342 pr_err("Failed to set shutdown watcher\n");
343 return err;
344 }
345
346
347#ifdef CONFIG_MAGIC_SYSRQ
348 err = register_xenbus_watch(&sysrq_watch);
349 if (err) {
350 pr_err("Failed to set sysrq watcher\n");
351 return err;
352 }
353#endif
354
355 return 0;
356}
357
358static int shutdown_event(struct notifier_block *notifier,
359 unsigned long event,
360 void *data)
361{
362 setup_shutdown_watcher();
363 return NOTIFY_DONE;
364}
365
366int xen_setup_shutdown_event(void)
367{
368 static struct notifier_block xenstore_notifier = {
369 .notifier_call = shutdown_event
370 };
371
372 if (!xen_domain())
373 return -ENODEV;
374 register_xenstore_notifier(&xenstore_notifier);
375 register_reboot_notifier(&xen_reboot_nb);
376
377 return 0;
378}
379EXPORT_SYMBOL_GPL(xen_setup_shutdown_event);
380
381subsys_initcall(xen_setup_shutdown_event);