/* * Handle extern requests for shutdown, reboot and sysrq */ #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt #include <linux/kernel.h> #include <linux/err.h> #include <linux/slab.h> #include <linux/reboot.h> #include <linux/sysrq.h> #include <linux/stop_machine.h> #include <linux/freezer.h> #include <linux/syscore_ops.h> #include <linux/export.h> #include <xen/xen.h> #include <xen/xenbus.h> #include <xen/grant_table.h> #include <xen/events.h> #include <xen/hvc-console.h> #include <xen/page.h> #include <xen/xen-ops.h> #include <asm/xen/hypercall.h> #include <asm/xen/hypervisor.h> enum shutdown_state { SHUTDOWN_INVALID = -1, SHUTDOWN_POWEROFF = 0, SHUTDOWN_SUSPEND = 2, /* Code 3 is SHUTDOWN_CRASH, which we don't use because the domain can only report a crash, not be instructed to crash! HALT is the same as POWEROFF, as far as we're concerned. The tools use the distinction when we return the reason code to them. */ SHUTDOWN_HALT = 4, }; /* Ignore multiple shutdown requests. */ static enum shutdown_state shutting_down = SHUTDOWN_INVALID; struct suspend_info { int cancelled; }; static RAW_NOTIFIER_HEAD(xen_resume_notifier); void xen_resume_notifier_register(struct notifier_block *nb) { raw_notifier_chain_register(&xen_resume_notifier, nb); } EXPORT_SYMBOL_GPL(xen_resume_notifier_register); void xen_resume_notifier_unregister(struct notifier_block *nb) { raw_notifier_chain_unregister(&xen_resume_notifier, nb); } EXPORT_SYMBOL_GPL(xen_resume_notifier_unregister); #ifdef CONFIG_HIBERNATE_CALLBACKS static int xen_suspend(void *data) { struct suspend_info *si = data; int err; BUG_ON(!irqs_disabled()); err = syscore_suspend(); if (err) { pr_err("%s: system core suspend failed: %d\n", __func__, err); return err; } gnttab_suspend(); xen_manage_runstate_time(-1); xen_arch_pre_suspend(); si->cancelled = HYPERVISOR_suspend(xen_pv_domain() ? virt_to_gfn(xen_start_info) : 0); xen_arch_post_suspend(si->cancelled); xen_manage_runstate_time(si->cancelled ? 1 : 0); gnttab_resume(); if (!si->cancelled) { xen_irq_resume(); xen_timer_resume(); } syscore_resume(); return 0; } static void do_suspend(void) { int err; struct suspend_info si; shutting_down = SHUTDOWN_SUSPEND; err = freeze_processes(); if (err) { pr_err("%s: freeze processes failed %d\n", __func__, err); goto out; } err = freeze_kernel_threads(); if (err) { pr_err("%s: freeze kernel threads failed %d\n", __func__, err); goto out_thaw; } err = dpm_suspend_start(PMSG_FREEZE); if (err) { pr_err("%s: dpm_suspend_start %d\n", __func__, err); goto out_thaw; } printk(KERN_DEBUG "suspending xenstore...\n"); xs_suspend(); err = dpm_suspend_end(PMSG_FREEZE); if (err) { pr_err("dpm_suspend_end failed: %d\n", err); si.cancelled = 0; goto out_resume; } xen_arch_suspend(); si.cancelled = 1; err = stop_machine(xen_suspend, &si, cpumask_of(0)); /* Resume console as early as possible. */ if (!si.cancelled) xen_console_resume(); raw_notifier_call_chain(&xen_resume_notifier, 0, NULL); dpm_resume_start(si.cancelled ? PMSG_THAW : PMSG_RESTORE); if (err) { pr_err("failed to start xen_suspend: %d\n", err); si.cancelled = 1; } xen_arch_resume(); out_resume: if (!si.cancelled) xs_resume(); else xs_suspend_cancel(); dpm_resume_end(si.cancelled ? PMSG_THAW : PMSG_RESTORE); out_thaw: thaw_processes(); out: shutting_down = SHUTDOWN_INVALID; } #endif /* CONFIG_HIBERNATE_CALLBACKS */ struct shutdown_handler { #define SHUTDOWN_CMD_SIZE 11 const char command[SHUTDOWN_CMD_SIZE]; bool flag; void (*cb)(void); }; static int poweroff_nb(struct notifier_block *cb, unsigned long code, void *unused) { switch (code) { case SYS_DOWN: case SYS_HALT: case SYS_POWER_OFF: shutting_down = SHUTDOWN_POWEROFF; default: break; } return NOTIFY_DONE; } static void do_poweroff(void) { switch (system_state) { case SYSTEM_BOOTING: case SYSTEM_SCHEDULING: orderly_poweroff(true); break; case SYSTEM_RUNNING: orderly_poweroff(false); break; default: /* Don't do it when we are halting/rebooting. */ pr_info("Ignoring Xen toolstack shutdown.\n"); break; } } static void do_reboot(void) { shutting_down = SHUTDOWN_POWEROFF; /* ? */ ctrl_alt_del(); } static struct shutdown_handler shutdown_handlers[] = { { "poweroff", true, do_poweroff }, { "halt", false, do_poweroff }, { "reboot", true, do_reboot }, #ifdef CONFIG_HIBERNATE_CALLBACKS { "suspend", true, do_suspend }, #endif }; static void shutdown_handler(struct xenbus_watch *watch, const char *path, const char *token) { char *str; struct xenbus_transaction xbt; int err; int idx; if (shutting_down != SHUTDOWN_INVALID) return; again: err = xenbus_transaction_start(&xbt); if (err) return; str = (char *)xenbus_read(xbt, "control", "shutdown", NULL); /* Ignore read errors and empty reads. */ if (XENBUS_IS_ERR_READ(str)) { xenbus_transaction_end(xbt, 1); return; } for (idx = 0; idx < ARRAY_SIZE(shutdown_handlers); idx++) { if (strcmp(str, shutdown_handlers[idx].command) == 0) break; } /* Only acknowledge commands which we are prepared to handle. */ if (idx < ARRAY_SIZE(shutdown_handlers)) xenbus_write(xbt, "control", "shutdown", ""); err = xenbus_transaction_end(xbt, 0); if (err == -EAGAIN) { kfree(str); goto again; } if (idx < ARRAY_SIZE(shutdown_handlers)) { shutdown_handlers[idx].cb(); } else { pr_info("Ignoring shutdown request: %s\n", str); shutting_down = SHUTDOWN_INVALID; } kfree(str); } #ifdef CONFIG_MAGIC_SYSRQ static void sysrq_handler(struct xenbus_watch *watch, const char *path, const char *token) { char sysrq_key = '\0'; struct xenbus_transaction xbt; int err; again: err = xenbus_transaction_start(&xbt); if (err) return; err = xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key); if (err < 0) { /* * The Xenstore watch fires directly after registering it and * after a suspend/resume cycle. So ENOENT is no error but * might happen in those cases. */ if (err != -ENOENT) pr_err("Error %d reading sysrq code in control/sysrq\n", err); xenbus_transaction_end(xbt, 1); return; } if (sysrq_key != '\0') xenbus_printf(xbt, "control", "sysrq", "%c", '\0'); err = xenbus_transaction_end(xbt, 0); if (err == -EAGAIN) goto again; if (sysrq_key != '\0') handle_sysrq(sysrq_key); } static struct xenbus_watch sysrq_watch = { .node = "control/sysrq", .callback = sysrq_handler }; #endif static struct xenbus_watch shutdown_watch = { .node = "control/shutdown", .callback = shutdown_handler }; static struct notifier_block xen_reboot_nb = { .notifier_call = poweroff_nb, }; static int setup_shutdown_watcher(void) { int err; int idx; #define FEATURE_PATH_SIZE (SHUTDOWN_CMD_SIZE + sizeof("feature-")) char node[FEATURE_PATH_SIZE]; err = register_xenbus_watch(&shutdown_watch); if (err) { pr_err("Failed to set shutdown watcher\n"); return err; } #ifdef CONFIG_MAGIC_SYSRQ err = register_xenbus_watch(&sysrq_watch); if (err) { pr_err("Failed to set sysrq watcher\n"); return err; } #endif for (idx = 0; idx < ARRAY_SIZE(shutdown_handlers); idx++) { if (!shutdown_handlers[idx].flag) continue; snprintf(node, FEATURE_PATH_SIZE, "feature-%s", shutdown_handlers[idx].command); xenbus_printf(XBT_NIL, "control", node, "%u", 1); } return 0; } static int shutdown_event(struct notifier_block *notifier, unsigned long event, void *data) { setup_shutdown_watcher(); return NOTIFY_DONE; } int xen_setup_shutdown_event(void) { static struct notifier_block xenstore_notifier = { .notifier_call = shutdown_event }; if (!xen_domain()) return -ENODEV; register_xenstore_notifier(&xenstore_notifier); register_reboot_notifier(&xen_reboot_nb); return 0; } EXPORT_SYMBOL_GPL(xen_setup_shutdown_event); subsys_initcall(xen_setup_shutdown_event);