Loading...
1/*
2 * Handle extern requests for shutdown, reboot and sysrq
3 */
4#include <linux/kernel.h>
5#include <linux/err.h>
6#include <linux/slab.h>
7#include <linux/reboot.h>
8#include <linux/sysrq.h>
9#include <linux/stop_machine.h>
10#include <linux/freezer.h>
11#include <linux/syscore_ops.h>
12#include <linux/export.h>
13
14#include <xen/xen.h>
15#include <xen/xenbus.h>
16#include <xen/grant_table.h>
17#include <xen/events.h>
18#include <xen/hvc-console.h>
19#include <xen/xen-ops.h>
20
21#include <asm/xen/hypercall.h>
22#include <asm/xen/page.h>
23#include <asm/xen/hypervisor.h>
24
25enum shutdown_state {
26 SHUTDOWN_INVALID = -1,
27 SHUTDOWN_POWEROFF = 0,
28 SHUTDOWN_SUSPEND = 2,
29 /* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only
30 report a crash, not be instructed to crash!
31 HALT is the same as POWEROFF, as far as we're concerned. The tools use
32 the distinction when we return the reason code to them. */
33 SHUTDOWN_HALT = 4,
34};
35
36/* Ignore multiple shutdown requests. */
37static enum shutdown_state shutting_down = SHUTDOWN_INVALID;
38
39struct suspend_info {
40 int cancelled;
41 unsigned long arg; /* extra hypercall argument */
42 void (*pre)(void);
43 void (*post)(int cancelled);
44};
45
46static void xen_hvm_post_suspend(int cancelled)
47{
48 xen_arch_hvm_post_suspend(cancelled);
49 gnttab_resume();
50}
51
52static void xen_pre_suspend(void)
53{
54 xen_mm_pin_all();
55 gnttab_suspend();
56 xen_arch_pre_suspend();
57}
58
59static void xen_post_suspend(int cancelled)
60{
61 xen_arch_post_suspend(cancelled);
62 gnttab_resume();
63 xen_mm_unpin_all();
64}
65
66#ifdef CONFIG_HIBERNATE_CALLBACKS
67static int xen_suspend(void *data)
68{
69 struct suspend_info *si = data;
70 int err;
71
72 BUG_ON(!irqs_disabled());
73
74 err = syscore_suspend();
75 if (err) {
76 printk(KERN_ERR "xen_suspend: system core suspend failed: %d\n",
77 err);
78 return err;
79 }
80
81 if (si->pre)
82 si->pre();
83
84 /*
85 * This hypercall returns 1 if suspend was cancelled
86 * or the domain was merely checkpointed, and 0 if it
87 * is resuming in a new domain.
88 */
89 si->cancelled = HYPERVISOR_suspend(si->arg);
90
91 if (si->post)
92 si->post(si->cancelled);
93
94 if (!si->cancelled) {
95 xen_irq_resume();
96 xen_console_resume();
97 xen_timer_resume();
98 }
99
100 syscore_resume();
101
102 return 0;
103}
104
105static void do_suspend(void)
106{
107 int err;
108 struct suspend_info si;
109
110 shutting_down = SHUTDOWN_SUSPEND;
111
112#ifdef CONFIG_PREEMPT
113 /* If the kernel is preemptible, we need to freeze all the processes
114 to prevent them from being in the middle of a pagetable update
115 during suspend. */
116 err = freeze_processes();
117 if (err) {
118 printk(KERN_ERR "xen suspend: freeze failed %d\n", err);
119 goto out;
120 }
121#endif
122
123 err = dpm_suspend_start(PMSG_FREEZE);
124 if (err) {
125 printk(KERN_ERR "xen suspend: dpm_suspend_start %d\n", err);
126 goto out_thaw;
127 }
128
129 printk(KERN_DEBUG "suspending xenstore...\n");
130 xs_suspend();
131
132 err = dpm_suspend_end(PMSG_FREEZE);
133 if (err) {
134 printk(KERN_ERR "dpm_suspend_end failed: %d\n", err);
135 si.cancelled = 0;
136 goto out_resume;
137 }
138
139 si.cancelled = 1;
140
141 if (xen_hvm_domain()) {
142 si.arg = 0UL;
143 si.pre = NULL;
144 si.post = &xen_hvm_post_suspend;
145 } else {
146 si.arg = virt_to_mfn(xen_start_info);
147 si.pre = &xen_pre_suspend;
148 si.post = &xen_post_suspend;
149 }
150
151 err = stop_machine(xen_suspend, &si, cpumask_of(0));
152
153 dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
154
155 if (err) {
156 printk(KERN_ERR "failed to start xen_suspend: %d\n", err);
157 si.cancelled = 1;
158 }
159
160out_resume:
161 if (!si.cancelled) {
162 xen_arch_resume();
163 xs_resume();
164 } else
165 xs_suspend_cancel();
166
167 dpm_resume_end(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
168
169 /* Make sure timer events get retriggered on all CPUs */
170 clock_was_set();
171
172out_thaw:
173#ifdef CONFIG_PREEMPT
174 thaw_processes();
175out:
176#endif
177 shutting_down = SHUTDOWN_INVALID;
178}
179#endif /* CONFIG_HIBERNATE_CALLBACKS */
180
181struct shutdown_handler {
182 const char *command;
183 void (*cb)(void);
184};
185
186static void do_poweroff(void)
187{
188 shutting_down = SHUTDOWN_POWEROFF;
189 orderly_poweroff(false);
190}
191
192static void do_reboot(void)
193{
194 shutting_down = SHUTDOWN_POWEROFF; /* ? */
195 ctrl_alt_del();
196}
197
198static void shutdown_handler(struct xenbus_watch *watch,
199 const char **vec, unsigned int len)
200{
201 char *str;
202 struct xenbus_transaction xbt;
203 int err;
204 static struct shutdown_handler handlers[] = {
205 { "poweroff", do_poweroff },
206 { "halt", do_poweroff },
207 { "reboot", do_reboot },
208#ifdef CONFIG_HIBERNATE_CALLBACKS
209 { "suspend", do_suspend },
210#endif
211 {NULL, NULL},
212 };
213 static struct shutdown_handler *handler;
214
215 if (shutting_down != SHUTDOWN_INVALID)
216 return;
217
218 again:
219 err = xenbus_transaction_start(&xbt);
220 if (err)
221 return;
222
223 str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
224 /* Ignore read errors and empty reads. */
225 if (XENBUS_IS_ERR_READ(str)) {
226 xenbus_transaction_end(xbt, 1);
227 return;
228 }
229
230 for (handler = &handlers[0]; handler->command; handler++) {
231 if (strcmp(str, handler->command) == 0)
232 break;
233 }
234
235 /* Only acknowledge commands which we are prepared to handle. */
236 if (handler->cb)
237 xenbus_write(xbt, "control", "shutdown", "");
238
239 err = xenbus_transaction_end(xbt, 0);
240 if (err == -EAGAIN) {
241 kfree(str);
242 goto again;
243 }
244
245 if (handler->cb) {
246 handler->cb();
247 } else {
248 printk(KERN_INFO "Ignoring shutdown request: %s\n", str);
249 shutting_down = SHUTDOWN_INVALID;
250 }
251
252 kfree(str);
253}
254
255#ifdef CONFIG_MAGIC_SYSRQ
256static void sysrq_handler(struct xenbus_watch *watch, const char **vec,
257 unsigned int len)
258{
259 char sysrq_key = '\0';
260 struct xenbus_transaction xbt;
261 int err;
262
263 again:
264 err = xenbus_transaction_start(&xbt);
265 if (err)
266 return;
267 if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) {
268 printk(KERN_ERR "Unable to read sysrq code in "
269 "control/sysrq\n");
270 xenbus_transaction_end(xbt, 1);
271 return;
272 }
273
274 if (sysrq_key != '\0')
275 xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
276
277 err = xenbus_transaction_end(xbt, 0);
278 if (err == -EAGAIN)
279 goto again;
280
281 if (sysrq_key != '\0')
282 handle_sysrq(sysrq_key);
283}
284
285static struct xenbus_watch sysrq_watch = {
286 .node = "control/sysrq",
287 .callback = sysrq_handler
288};
289#endif
290
291static struct xenbus_watch shutdown_watch = {
292 .node = "control/shutdown",
293 .callback = shutdown_handler
294};
295
296static int setup_shutdown_watcher(void)
297{
298 int err;
299
300 err = register_xenbus_watch(&shutdown_watch);
301 if (err) {
302 printk(KERN_ERR "Failed to set shutdown watcher\n");
303 return err;
304 }
305
306#ifdef CONFIG_MAGIC_SYSRQ
307 err = register_xenbus_watch(&sysrq_watch);
308 if (err) {
309 printk(KERN_ERR "Failed to set sysrq watcher\n");
310 return err;
311 }
312#endif
313
314 return 0;
315}
316
317static int shutdown_event(struct notifier_block *notifier,
318 unsigned long event,
319 void *data)
320{
321 setup_shutdown_watcher();
322 return NOTIFY_DONE;
323}
324
325int xen_setup_shutdown_event(void)
326{
327 static struct notifier_block xenstore_notifier = {
328 .notifier_call = shutdown_event
329 };
330
331 if (!xen_domain())
332 return -ENODEV;
333 register_xenstore_notifier(&xenstore_notifier);
334
335 return 0;
336}
337EXPORT_SYMBOL_GPL(xen_setup_shutdown_event);
338
339subsys_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_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);