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390 lines
8.3 KiB
390 lines
8.3 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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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/page.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/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_manage_runstate_time(-1); |
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xen_arch_pre_suspend(); |
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si->cancelled = HYPERVISOR_suspend(xen_pv_domain() |
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? virt_to_gfn(xen_start_info) |
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: 0); |
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xen_arch_post_suspend(si->cancelled); |
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xen_manage_runstate_time(si->cancelled ? 1 : 0); |
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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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#define SHUTDOWN_CMD_SIZE 11 |
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const char command[SHUTDOWN_CMD_SIZE]; |
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bool flag; |
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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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break; |
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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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case SYSTEM_SCHEDULING: |
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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 struct shutdown_handler shutdown_handlers[] = { |
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{ "poweroff", true, do_poweroff }, |
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{ "halt", false, do_poweroff }, |
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{ "reboot", true, do_reboot }, |
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#ifdef CONFIG_HIBERNATE_CALLBACKS |
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{ "suspend", true, do_suspend }, |
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#endif |
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}; |
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static void shutdown_handler(struct xenbus_watch *watch, |
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const char *path, const char *token) |
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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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int idx; |
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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 (idx = 0; idx < ARRAY_SIZE(shutdown_handlers); idx++) { |
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if (strcmp(str, shutdown_handlers[idx].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 (idx < ARRAY_SIZE(shutdown_handlers)) |
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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 (idx < ARRAY_SIZE(shutdown_handlers)) { |
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shutdown_handlers[idx].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 *path, |
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const char *token) |
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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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err = xenbus_scanf(xbt, "control", "sysrq", "%c", &sysrq_key); |
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if (err < 0) { |
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/* |
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* The Xenstore watch fires directly after registering it and |
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* after a suspend/resume cycle. So ENOENT is no error but |
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* might happen in those cases. ERANGE is observed when we get |
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* an empty value (''), this happens when we acknowledge the |
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* request by writing '\0' below. |
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*/ |
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if (err != -ENOENT && err != -ERANGE) |
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pr_err("Error %d reading sysrq code in control/sysrq\n", |
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err); |
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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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err = xenbus_printf(xbt, "control", "sysrq", "%c", '\0'); |
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if (err) { |
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pr_err("%s: Error %d writing sysrq in control/sysrq\n", |
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__func__, err); |
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xenbus_transaction_end(xbt, 1); |
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return; |
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} |
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} |
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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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int idx; |
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#define FEATURE_PATH_SIZE (SHUTDOWN_CMD_SIZE + sizeof("feature-")) |
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char node[FEATURE_PATH_SIZE]; |
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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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for (idx = 0; idx < ARRAY_SIZE(shutdown_handlers); idx++) { |
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if (!shutdown_handlers[idx].flag) |
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continue; |
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snprintf(node, FEATURE_PATH_SIZE, "feature-%s", |
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shutdown_handlers[idx].command); |
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err = xenbus_printf(XBT_NIL, "control", node, "%u", 1); |
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if (err) { |
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pr_err("%s: Error %d writing %s\n", __func__, |
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err, node); |
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return err; |
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} |
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} |
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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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