drivers/xen/manage.c

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