337 lines
6.7 KiB
C
337 lines
6.7 KiB
C
/*
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* Handle extern requests for shutdown, reboot and sysrq
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*/
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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 <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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unsigned long arg; /* extra hypercall argument */
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void (*pre)(void);
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void (*post)(int cancelled);
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};
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static void xen_hvm_post_suspend(int cancelled)
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{
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xen_arch_hvm_post_suspend(cancelled);
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gnttab_resume();
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}
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static void xen_pre_suspend(void)
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{
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xen_mm_pin_all();
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gnttab_suspend();
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xen_arch_pre_suspend();
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}
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static void xen_post_suspend(int cancelled)
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{
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xen_arch_post_suspend(cancelled);
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gnttab_resume();
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xen_mm_unpin_all();
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}
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#ifdef CONFIG_HIBERNATION
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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 = sysdev_suspend(PMSG_FREEZE);
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if (err) {
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printk(KERN_ERR "xen_suspend: sysdev_suspend failed: %d\n",
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err);
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return err;
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}
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if (si->pre)
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si->pre();
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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(si->arg);
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if (si->post)
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si->post(si->cancelled);
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if (!si->cancelled) {
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xen_irq_resume();
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xen_console_resume();
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xen_timer_resume();
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}
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sysdev_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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#ifdef CONFIG_PREEMPT
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/* If the kernel is preemptible, we need to freeze all the processes
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to prevent them from being in the middle of a pagetable update
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during suspend. */
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err = freeze_processes();
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if (err) {
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printk(KERN_ERR "xen suspend: freeze failed %d\n", err);
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goto out;
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}
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#endif
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err = dpm_suspend_start(PMSG_FREEZE);
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if (err) {
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printk(KERN_ERR "xen suspend: dpm_suspend_start %d\n", 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_noirq(PMSG_FREEZE);
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if (err) {
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printk(KERN_ERR "dpm_suspend_noirq failed: %d\n", err);
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goto out_resume;
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}
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si.cancelled = 1;
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if (xen_hvm_domain()) {
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si.arg = 0UL;
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si.pre = NULL;
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si.post = &xen_hvm_post_suspend;
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} else {
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si.arg = virt_to_mfn(xen_start_info);
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si.pre = &xen_pre_suspend;
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si.post = &xen_post_suspend;
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}
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err = stop_machine(xen_suspend, &si, cpumask_of(0));
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dpm_resume_noirq(si.cancelled ? PMSG_THAW : PMSG_RESTORE);
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if (err) {
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printk(KERN_ERR "failed to start xen_suspend: %d\n", err);
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si.cancelled = 1;
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}
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out_resume:
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if (!si.cancelled) {
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xen_arch_resume();
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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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/* Make sure timer events get retriggered on all CPUs */
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clock_was_set();
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out_thaw:
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#ifdef CONFIG_PREEMPT
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thaw_processes();
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out:
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#endif
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shutting_down = SHUTDOWN_INVALID;
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}
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#endif /* CONFIG_HIBERNATION */
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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 void do_poweroff(void)
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{
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shutting_down = SHUTDOWN_POWEROFF;
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orderly_poweroff(false);
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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_HIBERNATION
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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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printk(KERN_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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printk(KERN_ERR "Unable to read sysrq code in "
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"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 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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printk(KERN_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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printk(KERN_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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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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