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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
13#include <xen/xen.h>
14#include <xen/xenbus.h>
15#include <xen/grant_table.h>
16#include <xen/events.h>
17#include <xen/hvc-console.h>
18#include <xen/xen-ops.h>
19
20#include <asm/xen/hypercall.h>
21#include <asm/xen/page.h>
22#include <asm/xen/hypervisor.h>
23
24enum shutdown_state {
25 SHUTDOWN_INVALID = -1,
26 SHUTDOWN_POWEROFF = 0,
27 SHUTDOWN_SUSPEND = 2,
28 /* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only
29 report a crash, not be instructed to crash!
30 HALT is the same as POWEROFF, as far as we're concerned. The tools use
31 the distinction when we return the reason code to them. */
32 SHUTDOWN_HALT = 4,
33};
34
35/* Ignore multiple shutdown requests. */
36static enum shutdown_state shutting_down = SHUTDOWN_INVALID;
37
38struct suspend_info {
39 int cancelled;
40 unsigned long arg; /* extra hypercall argument */
41 void (*pre)(void);
42 void (*post)(int cancelled);
43};
44
45static void xen_hvm_post_suspend(int cancelled)
46{
47 xen_arch_hvm_post_suspend(cancelled);
48 gnttab_resume();
49}
50
51static void xen_pre_suspend(void)
52{
53 xen_mm_pin_all();
54 gnttab_suspend();
55 xen_arch_pre_suspend();
56}
57
58static void xen_post_suspend(int cancelled)
59{
60 xen_arch_post_suspend(cancelled);
61 gnttab_resume();
62 xen_mm_unpin_all();
63}
64
65#ifdef CONFIG_HIBERNATE_CALLBACKS
66static int xen_suspend(void *data)
67{
68 struct suspend_info *si = data;
69 int err;
70
71 BUG_ON(!irqs_disabled());
72
73 err = syscore_suspend();
74 if (err) {
75 printk(KERN_ERR "xen_suspend: system core suspend failed: %d\n",
76 err);
77 return err;
78 }
79
80 if (si->pre)
81 si->pre();
82
83 /*
84 * This hypercall returns 1 if suspend was cancelled
85 * or the domain was merely checkpointed, and 0 if it
86 * is resuming in a new domain.
87 */
88 si->cancelled = HYPERVISOR_suspend(si->arg);
89
90 if (si->post)
91 si->post(si->cancelled);
92
93 if (!si->cancelled) {
94 xen_irq_resume();
95 xen_console_resume();
96 xen_timer_resume();
97 }
98
99 syscore_resume();
100
101 return 0;
102}
103
104static void do_suspend(void)
105{
106 int err;
107 struct suspend_info si;
108
109 shutting_down = SHUTDOWN_SUSPEND;
110
111#ifdef CONFIG_PREEMPT
112 /* If the kernel is preemptible, we need to freeze all the processes
113 to prevent them from being in the middle of a pagetable update
114 during suspend. */
115 err = freeze_processes();
116 if (err) {
117 printk(KERN_ERR "xen suspend: freeze failed %d\n", err);
118 goto out;
119 }
120#endif
121
122 err = dpm_suspend_start(PMSG_FREEZE);
123 if (err) {
124 printk(KERN_ERR "xen suspend: dpm_suspend_start %d\n", err);
125 goto out_thaw;
126 }
127
128 printk(KERN_DEBUG "suspending xenstore...\n");
129 xs_suspend();
130
131 err = dpm_suspend_noirq(PMSG_FREEZE);
132 if (err) {
133 printk(KERN_ERR "dpm_suspend_noirq failed: %d\n", err);
134 goto out_resume;
135 }
136
137 si.cancelled = 1;
138
139 if (xen_hvm_domain()) {
140 si.arg = 0UL;
141 si.pre = NULL;
142 si.post = &xen_hvm_post_suspend;
143 } else {
144 si.arg = virt_to_mfn(xen_start_info);
145 si.pre = &xen_pre_suspend;
146 si.post = &xen_post_suspend;
147 }
148
149 err = stop_machine(xen_suspend, &si, cpumask_of(0));
150
151 dpm_resume_noirq(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
152
153 if (err) {
154 printk(KERN_ERR "failed to start xen_suspend: %d\n", err);
155 si.cancelled = 1;
156 }
157
158out_resume:
159 if (!si.cancelled) {
160 xen_arch_resume();
161 xs_resume();
162 } else
163 xs_suspend_cancel();
164
165 dpm_resume_end(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
166
167 /* Make sure timer events get retriggered on all CPUs */
168 clock_was_set();
169
170out_thaw:
171#ifdef CONFIG_PREEMPT
172 thaw_processes();
173out:
174#endif
175 shutting_down = SHUTDOWN_INVALID;
176}
177#endif /* CONFIG_HIBERNATE_CALLBACKS */
178
179struct shutdown_handler {
180 const char *command;
181 void (*cb)(void);
182};
183
184static void do_poweroff(void)
185{
186 shutting_down = SHUTDOWN_POWEROFF;
187 orderly_poweroff(false);
188}
189
190static void do_reboot(void)
191{
192 shutting_down = SHUTDOWN_POWEROFF; /* ? */
193 ctrl_alt_del();
194}
195
196static void shutdown_handler(struct xenbus_watch *watch,
197 const char **vec, unsigned int len)
198{
199 char *str;
200 struct xenbus_transaction xbt;
201 int err;
202 static struct shutdown_handler handlers[] = {
203 { "poweroff", do_poweroff },
204 { "halt", do_poweroff },
205 { "reboot", do_reboot },
206#ifdef CONFIG_HIBERNATE_CALLBACKS
207 { "suspend", do_suspend },
208#endif
209 {NULL, NULL},
210 };
211 static struct shutdown_handler *handler;
212
213 if (shutting_down != SHUTDOWN_INVALID)
214 return;
215
216 again:
217 err = xenbus_transaction_start(&xbt);
218 if (err)
219 return;
220
221 str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
222 /* Ignore read errors and empty reads. */
223 if (XENBUS_IS_ERR_READ(str)) {
224 xenbus_transaction_end(xbt, 1);
225 return;
226 }
227
228 for (handler = &handlers[0]; handler->command; handler++) {
229 if (strcmp(str, handler->command) == 0)
230 break;
231 }
232
233 /* Only acknowledge commands which we are prepared to handle. */
234 if (handler->cb)
235 xenbus_write(xbt, "control", "shutdown", "");
236
237 err = xenbus_transaction_end(xbt, 0);
238 if (err == -EAGAIN) {
239 kfree(str);
240 goto again;
241 }
242
243 if (handler->cb) {
244 handler->cb();
245 } else {
246 printk(KERN_INFO "Ignoring shutdown request: %s\n", str);
247 shutting_down = SHUTDOWN_INVALID;
248 }
249
250 kfree(str);
251}
252
253#ifdef CONFIG_MAGIC_SYSRQ
254static void sysrq_handler(struct xenbus_watch *watch, const char **vec,
255 unsigned int len)
256{
257 char sysrq_key = '\0';
258 struct xenbus_transaction xbt;
259 int err;
260
261 again:
262 err = xenbus_transaction_start(&xbt);
263 if (err)
264 return;
265 if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) {
266 printk(KERN_ERR "Unable to read sysrq code in "
267 "control/sysrq\n");
268 xenbus_transaction_end(xbt, 1);
269 return;
270 }
271
272 if (sysrq_key != '\0')
273 xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
274
275 err = xenbus_transaction_end(xbt, 0);
276 if (err == -EAGAIN)
277 goto again;
278
279 if (sysrq_key != '\0')
280 handle_sysrq(sysrq_key);
281}
282
283static struct xenbus_watch sysrq_watch = {
284 .node = "control/sysrq",
285 .callback = sysrq_handler
286};
287#endif
288
289static struct xenbus_watch shutdown_watch = {
290 .node = "control/shutdown",
291 .callback = shutdown_handler
292};
293
294static int setup_shutdown_watcher(void)
295{
296 int err;
297
298 err = register_xenbus_watch(&shutdown_watch);
299 if (err) {
300 printk(KERN_ERR "Failed to set shutdown watcher\n");
301 return err;
302 }
303
304#ifdef CONFIG_MAGIC_SYSRQ
305 err = register_xenbus_watch(&sysrq_watch);
306 if (err) {
307 printk(KERN_ERR "Failed to set sysrq watcher\n");
308 return err;
309 }
310#endif
311
312 return 0;
313}
314
315static int shutdown_event(struct notifier_block *notifier,
316 unsigned long event,
317 void *data)
318{
319 setup_shutdown_watcher();
320 return NOTIFY_DONE;
321}
322
323int xen_setup_shutdown_event(void)
324{
325 static struct notifier_block xenstore_notifier = {
326 .notifier_call = shutdown_event
327 };
328
329 if (!xen_domain())
330 return -ENODEV;
331 register_xenstore_notifier(&xenstore_notifier);
332
333 return 0;
334}
335EXPORT_SYMBOL_GPL(xen_setup_shutdown_event);
336
337subsys_initcall(xen_setup_shutdown_event);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Handle extern requests for shutdown, reboot and sysrq
4 */
5
6#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
7
8#include <linux/kernel.h>
9#include <linux/err.h>
10#include <linux/slab.h>
11#include <linux/reboot.h>
12#include <linux/sysrq.h>
13#include <linux/stop_machine.h>
14#include <linux/freezer.h>
15#include <linux/syscore_ops.h>
16#include <linux/export.h>
17
18#include <xen/xen.h>
19#include <xen/xenbus.h>
20#include <xen/grant_table.h>
21#include <xen/events.h>
22#include <xen/hvc-console.h>
23#include <xen/page.h>
24#include <xen/xen-ops.h>
25
26#include <asm/xen/hypercall.h>
27#include <asm/xen/hypervisor.h>
28
29enum shutdown_state {
30 SHUTDOWN_INVALID = -1,
31 SHUTDOWN_POWEROFF = 0,
32 SHUTDOWN_SUSPEND = 2,
33 /* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only
34 report a crash, not be instructed to crash!
35 HALT is the same as POWEROFF, as far as we're concerned. The tools use
36 the distinction when we return the reason code to them. */
37 SHUTDOWN_HALT = 4,
38};
39
40/* Ignore multiple shutdown requests. */
41static enum shutdown_state shutting_down = SHUTDOWN_INVALID;
42
43struct suspend_info {
44 int cancelled;
45};
46
47static RAW_NOTIFIER_HEAD(xen_resume_notifier);
48
49void xen_resume_notifier_register(struct notifier_block *nb)
50{
51 raw_notifier_chain_register(&xen_resume_notifier, nb);
52}
53EXPORT_SYMBOL_GPL(xen_resume_notifier_register);
54
55void xen_resume_notifier_unregister(struct notifier_block *nb)
56{
57 raw_notifier_chain_unregister(&xen_resume_notifier, nb);
58}
59EXPORT_SYMBOL_GPL(xen_resume_notifier_unregister);
60
61#ifdef CONFIG_HIBERNATE_CALLBACKS
62static int xen_suspend(void *data)
63{
64 struct suspend_info *si = data;
65 int err;
66
67 BUG_ON(!irqs_disabled());
68
69 err = syscore_suspend();
70 if (err) {
71 pr_err("%s: system core suspend failed: %d\n", __func__, err);
72 return err;
73 }
74
75 gnttab_suspend();
76 xen_manage_runstate_time(-1);
77 xen_arch_pre_suspend();
78
79 si->cancelled = HYPERVISOR_suspend(xen_pv_domain()
80 ? virt_to_gfn(xen_start_info)
81 : 0);
82
83 xen_arch_post_suspend(si->cancelled);
84 xen_manage_runstate_time(si->cancelled ? 1 : 0);
85 gnttab_resume();
86
87 if (!si->cancelled) {
88 xen_irq_resume();
89 xen_timer_resume();
90 }
91
92 syscore_resume();
93
94 return 0;
95}
96
97static void do_suspend(void)
98{
99 int err;
100 struct suspend_info si;
101
102 shutting_down = SHUTDOWN_SUSPEND;
103
104 err = freeze_processes();
105 if (err) {
106 pr_err("%s: freeze processes failed %d\n", __func__, err);
107 goto out;
108 }
109
110 err = freeze_kernel_threads();
111 if (err) {
112 pr_err("%s: freeze kernel threads failed %d\n", __func__, err);
113 goto out_thaw;
114 }
115
116 err = dpm_suspend_start(PMSG_FREEZE);
117 if (err) {
118 pr_err("%s: dpm_suspend_start %d\n", __func__, err);
119 goto out_thaw;
120 }
121
122 printk(KERN_DEBUG "suspending xenstore...\n");
123 xs_suspend();
124
125 err = dpm_suspend_end(PMSG_FREEZE);
126 if (err) {
127 pr_err("dpm_suspend_end failed: %d\n", err);
128 si.cancelled = 0;
129 goto out_resume;
130 }
131
132 xen_arch_suspend();
133
134 si.cancelled = 1;
135
136 err = stop_machine(xen_suspend, &si, cpumask_of(0));
137
138 /* Resume console as early as possible. */
139 if (!si.cancelled)
140 xen_console_resume();
141
142 raw_notifier_call_chain(&xen_resume_notifier, 0, NULL);
143
144 dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
145
146 if (err) {
147 pr_err("failed to start xen_suspend: %d\n", err);
148 si.cancelled = 1;
149 }
150
151 xen_arch_resume();
152
153out_resume:
154 if (!si.cancelled)
155 xs_resume();
156 else
157 xs_suspend_cancel();
158
159 dpm_resume_end(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
160
161out_thaw:
162 thaw_processes();
163out:
164 shutting_down = SHUTDOWN_INVALID;
165}
166#endif /* CONFIG_HIBERNATE_CALLBACKS */
167
168struct shutdown_handler {
169#define SHUTDOWN_CMD_SIZE 11
170 const char command[SHUTDOWN_CMD_SIZE];
171 bool flag;
172 void (*cb)(void);
173};
174
175static int poweroff_nb(struct notifier_block *cb, unsigned long code, void *unused)
176{
177 switch (code) {
178 case SYS_DOWN:
179 case SYS_HALT:
180 case SYS_POWER_OFF:
181 shutting_down = SHUTDOWN_POWEROFF;
182 default:
183 break;
184 }
185 return NOTIFY_DONE;
186}
187static void do_poweroff(void)
188{
189 switch (system_state) {
190 case SYSTEM_BOOTING:
191 case SYSTEM_SCHEDULING:
192 orderly_poweroff(true);
193 break;
194 case SYSTEM_RUNNING:
195 orderly_poweroff(false);
196 break;
197 default:
198 /* Don't do it when we are halting/rebooting. */
199 pr_info("Ignoring Xen toolstack shutdown.\n");
200 break;
201 }
202}
203
204static void do_reboot(void)
205{
206 shutting_down = SHUTDOWN_POWEROFF; /* ? */
207 ctrl_alt_del();
208}
209
210static struct shutdown_handler shutdown_handlers[] = {
211 { "poweroff", true, do_poweroff },
212 { "halt", false, do_poweroff },
213 { "reboot", true, do_reboot },
214#ifdef CONFIG_HIBERNATE_CALLBACKS
215 { "suspend", true, do_suspend },
216#endif
217};
218
219static void shutdown_handler(struct xenbus_watch *watch,
220 const char *path, const char *token)
221{
222 char *str;
223 struct xenbus_transaction xbt;
224 int err;
225 int idx;
226
227 if (shutting_down != SHUTDOWN_INVALID)
228 return;
229
230 again:
231 err = xenbus_transaction_start(&xbt);
232 if (err)
233 return;
234
235 str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
236 /* Ignore read errors and empty reads. */
237 if (XENBUS_IS_ERR_READ(str)) {
238 xenbus_transaction_end(xbt, 1);
239 return;
240 }
241
242 for (idx = 0; idx < ARRAY_SIZE(shutdown_handlers); idx++) {
243 if (strcmp(str, shutdown_handlers[idx].command) == 0)
244 break;
245 }
246
247 /* Only acknowledge commands which we are prepared to handle. */
248 if (idx < ARRAY_SIZE(shutdown_handlers))
249 xenbus_write(xbt, "control", "shutdown", "");
250
251 err = xenbus_transaction_end(xbt, 0);
252 if (err == -EAGAIN) {
253 kfree(str);
254 goto again;
255 }
256
257 if (idx < ARRAY_SIZE(shutdown_handlers)) {
258 shutdown_handlers[idx].cb();
259 } else {
260 pr_info("Ignoring shutdown request: %s\n", str);
261 shutting_down = SHUTDOWN_INVALID;
262 }
263
264 kfree(str);
265}
266
267#ifdef CONFIG_MAGIC_SYSRQ
268static void sysrq_handler(struct xenbus_watch *watch, const char *path,
269 const char *token)
270{
271 char sysrq_key = '\0';
272 struct xenbus_transaction xbt;
273 int err;
274
275 again:
276 err = xenbus_transaction_start(&xbt);
277 if (err)
278 return;
279 err = xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key);
280 if (err < 0) {
281 /*
282 * The Xenstore watch fires directly after registering it and
283 * after a suspend/resume cycle. So ENOENT is no error but
284 * might happen in those cases. ERANGE is observed when we get
285 * an empty value (''), this happens when we acknowledge the
286 * request by writing '\0' below.
287 */
288 if (err != -ENOENT && err != -ERANGE)
289 pr_err("Error %d reading sysrq code in control/sysrq\n",
290 err);
291 xenbus_transaction_end(xbt, 1);
292 return;
293 }
294
295 if (sysrq_key != '\0') {
296 err = xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
297 if (err) {
298 pr_err("%s: Error %d writing sysrq in control/sysrq\n",
299 __func__, err);
300 xenbus_transaction_end(xbt, 1);
301 return;
302 }
303 }
304
305 err = xenbus_transaction_end(xbt, 0);
306 if (err == -EAGAIN)
307 goto again;
308
309 if (sysrq_key != '\0')
310 handle_sysrq(sysrq_key);
311}
312
313static struct xenbus_watch sysrq_watch = {
314 .node = "control/sysrq",
315 .callback = sysrq_handler
316};
317#endif
318
319static struct xenbus_watch shutdown_watch = {
320 .node = "control/shutdown",
321 .callback = shutdown_handler
322};
323
324static struct notifier_block xen_reboot_nb = {
325 .notifier_call = poweroff_nb,
326};
327
328static int setup_shutdown_watcher(void)
329{
330 int err;
331 int idx;
332#define FEATURE_PATH_SIZE (SHUTDOWN_CMD_SIZE + sizeof("feature-"))
333 char node[FEATURE_PATH_SIZE];
334
335 err = register_xenbus_watch(&shutdown_watch);
336 if (err) {
337 pr_err("Failed to set shutdown watcher\n");
338 return err;
339 }
340
341
342#ifdef CONFIG_MAGIC_SYSRQ
343 err = register_xenbus_watch(&sysrq_watch);
344 if (err) {
345 pr_err("Failed to set sysrq watcher\n");
346 return err;
347 }
348#endif
349
350 for (idx = 0; idx < ARRAY_SIZE(shutdown_handlers); idx++) {
351 if (!shutdown_handlers[idx].flag)
352 continue;
353 snprintf(node, FEATURE_PATH_SIZE, "feature-%s",
354 shutdown_handlers[idx].command);
355 err = xenbus_printf(XBT_NIL, "control", node, "%u", 1);
356 if (err) {
357 pr_err("%s: Error %d writing %s\n", __func__,
358 err, node);
359 return err;
360 }
361 }
362
363 return 0;
364}
365
366static int shutdown_event(struct notifier_block *notifier,
367 unsigned long event,
368 void *data)
369{
370 setup_shutdown_watcher();
371 return NOTIFY_DONE;
372}
373
374int xen_setup_shutdown_event(void)
375{
376 static struct notifier_block xenstore_notifier = {
377 .notifier_call = shutdown_event
378 };
379
380 if (!xen_domain())
381 return -ENODEV;
382 register_xenstore_notifier(&xenstore_notifier);
383 register_reboot_notifier(&xen_reboot_nb);
384
385 return 0;
386}
387EXPORT_SYMBOL_GPL(xen_setup_shutdown_event);
388
389subsys_initcall(xen_setup_shutdown_event);