![Boris Ostrovsky](/assets/img/avatar_default.png)
Commit 77e32c89a7
("clockevents: Manage device's state separately for
the core") decouples clockevent device's modes from states. With this
change when a Xen guest tries to resume, it won't be calling its
set_mode op which needs to be done on each VCPU in order to make the
hypervisor aware that we are in oneshot mode.
This happens because clockevents_tick_resume() (which is an intermediate
step of resuming ticks on a processor) doesn't call clockevents_set_state()
anymore and because during suspend clockevent devices on all VCPUs (except
for the one doing the suspend) are left in ONESHOT state. As result, during
resume the clockevents state machine will assume that device is already
where it should be and doesn't need to be updated.
To avoid this problem we should suspend ticks on all VCPUs during
suspend.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
356 lines
7.2 KiB
C
356 lines
7.2 KiB
C
/*
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* Handle extern requests for shutdown, reboot and sysrq
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*/
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#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
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#include <linux/kernel.h>
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#include <linux/err.h>
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#include <linux/slab.h>
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#include <linux/reboot.h>
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#include <linux/sysrq.h>
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#include <linux/stop_machine.h>
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#include <linux/freezer.h>
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#include <linux/syscore_ops.h>
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#include <linux/export.h>
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#include <xen/xen.h>
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#include <xen/xenbus.h>
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#include <xen/grant_table.h>
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#include <xen/events.h>
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#include <xen/hvc-console.h>
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#include <xen/xen-ops.h>
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#include <asm/xen/hypercall.h>
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#include <asm/xen/page.h>
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#include <asm/xen/hypervisor.h>
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enum shutdown_state {
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SHUTDOWN_INVALID = -1,
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SHUTDOWN_POWEROFF = 0,
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SHUTDOWN_SUSPEND = 2,
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/* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only
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report a crash, not be instructed to crash!
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HALT is the same as POWEROFF, as far as we're concerned. The tools use
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the distinction when we return the reason code to them. */
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SHUTDOWN_HALT = 4,
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};
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/* Ignore multiple shutdown requests. */
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static enum shutdown_state shutting_down = SHUTDOWN_INVALID;
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struct suspend_info {
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int cancelled;
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};
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static RAW_NOTIFIER_HEAD(xen_resume_notifier);
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void xen_resume_notifier_register(struct notifier_block *nb)
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{
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raw_notifier_chain_register(&xen_resume_notifier, nb);
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}
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EXPORT_SYMBOL_GPL(xen_resume_notifier_register);
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void xen_resume_notifier_unregister(struct notifier_block *nb)
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{
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raw_notifier_chain_unregister(&xen_resume_notifier, nb);
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}
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EXPORT_SYMBOL_GPL(xen_resume_notifier_unregister);
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#ifdef CONFIG_HIBERNATE_CALLBACKS
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static int xen_suspend(void *data)
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{
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struct suspend_info *si = data;
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int err;
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BUG_ON(!irqs_disabled());
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err = syscore_suspend();
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if (err) {
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pr_err("%s: system core suspend failed: %d\n", __func__, err);
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return err;
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}
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gnttab_suspend();
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xen_arch_pre_suspend();
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/*
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* This hypercall returns 1 if suspend was cancelled
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* or the domain was merely checkpointed, and 0 if it
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* is resuming in a new domain.
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*/
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si->cancelled = HYPERVISOR_suspend(xen_pv_domain()
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? virt_to_mfn(xen_start_info)
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: 0);
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xen_arch_post_suspend(si->cancelled);
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gnttab_resume();
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if (!si->cancelled) {
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xen_irq_resume();
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xen_timer_resume();
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}
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syscore_resume();
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return 0;
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}
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static void do_suspend(void)
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{
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int err;
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struct suspend_info si;
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shutting_down = SHUTDOWN_SUSPEND;
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err = freeze_processes();
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if (err) {
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pr_err("%s: freeze processes failed %d\n", __func__, err);
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goto out;
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}
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err = freeze_kernel_threads();
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if (err) {
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pr_err("%s: freeze kernel threads failed %d\n", __func__, err);
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goto out_thaw;
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}
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err = dpm_suspend_start(PMSG_FREEZE);
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if (err) {
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pr_err("%s: dpm_suspend_start %d\n", __func__, err);
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goto out_thaw;
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}
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printk(KERN_DEBUG "suspending xenstore...\n");
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xs_suspend();
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err = dpm_suspend_end(PMSG_FREEZE);
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if (err) {
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pr_err("dpm_suspend_end failed: %d\n", err);
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si.cancelled = 0;
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goto out_resume;
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}
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xen_arch_suspend();
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si.cancelled = 1;
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err = stop_machine(xen_suspend, &si, cpumask_of(0));
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/* Resume console as early as possible. */
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if (!si.cancelled)
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xen_console_resume();
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raw_notifier_call_chain(&xen_resume_notifier, 0, NULL);
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dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
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if (err) {
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pr_err("failed to start xen_suspend: %d\n", err);
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si.cancelled = 1;
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}
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xen_arch_resume();
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out_resume:
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if (!si.cancelled)
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xs_resume();
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else
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xs_suspend_cancel();
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dpm_resume_end(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
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out_thaw:
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thaw_processes();
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out:
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shutting_down = SHUTDOWN_INVALID;
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}
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#endif /* CONFIG_HIBERNATE_CALLBACKS */
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struct shutdown_handler {
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const char *command;
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void (*cb)(void);
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};
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static int poweroff_nb(struct notifier_block *cb, unsigned long code, void *unused)
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{
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switch (code) {
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case SYS_DOWN:
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case SYS_HALT:
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case SYS_POWER_OFF:
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shutting_down = SHUTDOWN_POWEROFF;
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default:
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break;
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}
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return NOTIFY_DONE;
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}
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static void do_poweroff(void)
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{
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switch (system_state) {
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case SYSTEM_BOOTING:
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orderly_poweroff(true);
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break;
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case SYSTEM_RUNNING:
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orderly_poweroff(false);
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break;
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default:
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/* Don't do it when we are halting/rebooting. */
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pr_info("Ignoring Xen toolstack shutdown.\n");
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break;
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}
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}
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static void do_reboot(void)
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{
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shutting_down = SHUTDOWN_POWEROFF; /* ? */
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ctrl_alt_del();
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}
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static void shutdown_handler(struct xenbus_watch *watch,
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const char **vec, unsigned int len)
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{
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char *str;
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struct xenbus_transaction xbt;
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int err;
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static struct shutdown_handler handlers[] = {
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{ "poweroff", do_poweroff },
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{ "halt", do_poweroff },
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{ "reboot", do_reboot },
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#ifdef CONFIG_HIBERNATE_CALLBACKS
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{ "suspend", do_suspend },
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#endif
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{NULL, NULL},
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};
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static struct shutdown_handler *handler;
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if (shutting_down != SHUTDOWN_INVALID)
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return;
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again:
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err = xenbus_transaction_start(&xbt);
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if (err)
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return;
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str = (char *)xenbus_read(xbt, "control", "shutdown", NULL);
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/* Ignore read errors and empty reads. */
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if (XENBUS_IS_ERR_READ(str)) {
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xenbus_transaction_end(xbt, 1);
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return;
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}
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for (handler = &handlers[0]; handler->command; handler++) {
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if (strcmp(str, handler->command) == 0)
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break;
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}
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/* Only acknowledge commands which we are prepared to handle. */
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if (handler->cb)
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xenbus_write(xbt, "control", "shutdown", "");
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err = xenbus_transaction_end(xbt, 0);
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if (err == -EAGAIN) {
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kfree(str);
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goto again;
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}
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if (handler->cb) {
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handler->cb();
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} else {
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pr_info("Ignoring shutdown request: %s\n", str);
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shutting_down = SHUTDOWN_INVALID;
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}
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kfree(str);
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}
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#ifdef CONFIG_MAGIC_SYSRQ
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static void sysrq_handler(struct xenbus_watch *watch, const char **vec,
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unsigned int len)
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{
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char sysrq_key = '\0';
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struct xenbus_transaction xbt;
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int err;
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again:
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err = xenbus_transaction_start(&xbt);
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if (err)
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return;
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if (!xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key)) {
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pr_err("Unable to read sysrq code in control/sysrq\n");
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xenbus_transaction_end(xbt, 1);
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return;
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}
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if (sysrq_key != '\0')
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xenbus_printf(xbt, "control", "sysrq", "%c", '\0');
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err = xenbus_transaction_end(xbt, 0);
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if (err == -EAGAIN)
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goto again;
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if (sysrq_key != '\0')
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handle_sysrq(sysrq_key);
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}
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static struct xenbus_watch sysrq_watch = {
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.node = "control/sysrq",
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.callback = sysrq_handler
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};
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#endif
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static struct xenbus_watch shutdown_watch = {
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.node = "control/shutdown",
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.callback = shutdown_handler
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};
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static struct notifier_block xen_reboot_nb = {
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.notifier_call = poweroff_nb,
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};
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static int setup_shutdown_watcher(void)
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{
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int err;
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err = register_xenbus_watch(&shutdown_watch);
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if (err) {
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pr_err("Failed to set shutdown watcher\n");
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return err;
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}
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#ifdef CONFIG_MAGIC_SYSRQ
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err = register_xenbus_watch(&sysrq_watch);
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if (err) {
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pr_err("Failed to set sysrq watcher\n");
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return err;
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}
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#endif
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return 0;
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}
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static int shutdown_event(struct notifier_block *notifier,
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unsigned long event,
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void *data)
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{
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setup_shutdown_watcher();
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return NOTIFY_DONE;
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}
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int xen_setup_shutdown_event(void)
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{
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static struct notifier_block xenstore_notifier = {
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.notifier_call = shutdown_event
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};
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if (!xen_domain())
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return -ENODEV;
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register_xenstore_notifier(&xenstore_notifier);
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register_reboot_notifier(&xen_reboot_nb);
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return 0;
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}
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EXPORT_SYMBOL_GPL(xen_setup_shutdown_event);
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subsys_initcall(xen_setup_shutdown_event);
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