--- /dev/null
+/*
+ * linux/kernel/power/user.c
+ *
+ * This file provides the user space interface for software suspend/resume.
+ *
+ * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
+ *
+ * This file is released under the GPLv2.
+ *
+ */
+
+#include <linux/suspend.h>
+#include <linux/syscalls.h>
+#include <linux/reboot.h>
+#include <linux/string.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+#include <linux/mm.h>
+#include <linux/swap.h>
+#include <linux/swapops.h>
+#include <linux/pm.h>
+#include <linux/fs.h>
+#include <linux/compat.h>
+#include <linux/console.h>
+#include <linux/cpu.h>
+#include <linux/freezer.h>
+
+#include <asm/uaccess.h>
+
+#include "power.h"
+
+
+#define SNAPSHOT_MINOR 231
+
+static struct snapshot_data {
+ struct snapshot_handle handle;
+ int swap;
+ int mode;
+ bool frozen;
+ bool ready;
+ bool platform_support;
+ bool free_bitmaps;
+} snapshot_state;
+
+atomic_t snapshot_device_available = ATOMIC_INIT(1);
+
+static int snapshot_open(struct inode *inode, struct file *filp)
+{
+ struct snapshot_data *data;
+ int error;
+
+ if (!hibernation_available())
+ return -EPERM;
+
+ lock_system_sleep();
+
+ if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
+ error = -EBUSY;
+ goto Unlock;
+ }
+
+ if ((filp->f_flags & O_ACCMODE) == O_RDWR) {
+ atomic_inc(&snapshot_device_available);
+ error = -ENOSYS;
+ goto Unlock;
+ }
+ nonseekable_open(inode, filp);
+ data = &snapshot_state;
+ filp->private_data = data;
+ memset(&data->handle, 0, sizeof(struct snapshot_handle));
+ if ((filp->f_flags & O_ACCMODE) == O_RDONLY) {
+ /* Hibernating. The image device should be accessible. */
+ data->swap = swsusp_resume_device ?
+ swap_type_of(swsusp_resume_device, 0, NULL) : -1;
+ data->mode = O_RDONLY;
+ data->free_bitmaps = false;
+ error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE);
+ if (error)
+ pm_notifier_call_chain(PM_POST_HIBERNATION);
+ } else {
+ /*
+ * Resuming. We may need to wait for the image device to
+ * appear.
+ */
+ wait_for_device_probe();
+
+ data->swap = -1;
+ data->mode = O_WRONLY;
+ error = pm_notifier_call_chain(PM_RESTORE_PREPARE);
+ if (!error) {
+ error = create_basic_memory_bitmaps();
+ data->free_bitmaps = !error;
+ }
+ if (error)
+ pm_notifier_call_chain(PM_POST_RESTORE);
+ }
+ if (error)
+ atomic_inc(&snapshot_device_available);
+
+ data->frozen = false;
+ data->ready = false;
+ data->platform_support = false;
+
+ Unlock:
+ unlock_system_sleep();
+
+ return error;
+}
+
+static int snapshot_release(struct inode *inode, struct file *filp)
+{
+ struct snapshot_data *data;
+
+ lock_system_sleep();
+
+ swsusp_free();
+ data = filp->private_data;
+ free_all_swap_pages(data->swap);
+ if (data->frozen) {
+ pm_restore_gfp_mask();
+ free_basic_memory_bitmaps();
+ thaw_processes();
+ } else if (data->free_bitmaps) {
+ free_basic_memory_bitmaps();
+ }
+ pm_notifier_call_chain(data->mode == O_RDONLY ?
+ PM_POST_HIBERNATION : PM_POST_RESTORE);
+ atomic_inc(&snapshot_device_available);
+
+ unlock_system_sleep();
+
+ return 0;
+}
+
+static ssize_t snapshot_read(struct file *filp, char __user *buf,
+ size_t count, loff_t *offp)
+{
+ struct snapshot_data *data;
+ ssize_t res;
+ loff_t pg_offp = *offp & ~PAGE_MASK;
+
+ lock_system_sleep();
+
+ data = filp->private_data;
+ if (!data->ready) {
+ res = -ENODATA;
+ goto Unlock;
+ }
+ if (!pg_offp) { /* on page boundary? */
+ res = snapshot_read_next(&data->handle);
+ if (res <= 0)
+ goto Unlock;
+ } else {
+ res = PAGE_SIZE - pg_offp;
+ }
+
+ res = simple_read_from_buffer(buf, count, &pg_offp,
+ data_of(data->handle), res);
+ if (res > 0)
+ *offp += res;
+
+ Unlock:
+ unlock_system_sleep();
+
+ return res;
+}
+
+static ssize_t snapshot_write(struct file *filp, const char __user *buf,
+ size_t count, loff_t *offp)
+{
+ struct snapshot_data *data;
+ ssize_t res;
+ loff_t pg_offp = *offp & ~PAGE_MASK;
+
+ lock_system_sleep();
+
+ data = filp->private_data;
+
+ if (!pg_offp) {
+ res = snapshot_write_next(&data->handle);
+ if (res <= 0)
+ goto unlock;
+ } else {
+ res = PAGE_SIZE - pg_offp;
+ }
+
+ res = simple_write_to_buffer(data_of(data->handle), res, &pg_offp,
+ buf, count);
+ if (res > 0)
+ *offp += res;
+unlock:
+ unlock_system_sleep();
+
+ return res;
+}
+
+static long snapshot_ioctl(struct file *filp, unsigned int cmd,
+ unsigned long arg)
+{
+ int error = 0;
+ struct snapshot_data *data;
+ loff_t size;
+ sector_t offset;
+
+ if (_IOC_TYPE(cmd) != SNAPSHOT_IOC_MAGIC)
+ return -ENOTTY;
+ if (_IOC_NR(cmd) > SNAPSHOT_IOC_MAXNR)
+ return -ENOTTY;
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ if (!mutex_trylock(&pm_mutex))
+ return -EBUSY;
+
+ lock_device_hotplug();
+ data = filp->private_data;
+
+ switch (cmd) {
+
+ case SNAPSHOT_FREEZE:
+ if (data->frozen)
+ break;
+
+ printk("Syncing filesystems ... ");
+ sys_sync();
+ printk("done.\n");
+
+ error = freeze_processes();
+ if (error)
+ break;
+
+ error = create_basic_memory_bitmaps();
+ if (error)
+ thaw_processes();
+ else
+ data->frozen = true;
+
+ break;
+
+ case SNAPSHOT_UNFREEZE:
+ if (!data->frozen || data->ready)
+ break;
+ pm_restore_gfp_mask();
+ free_basic_memory_bitmaps();
+ data->free_bitmaps = false;
+ thaw_processes();
+ data->frozen = false;
+ break;
+
+ case SNAPSHOT_CREATE_IMAGE:
+ if (data->mode != O_RDONLY || !data->frozen || data->ready) {
+ error = -EPERM;
+ break;
+ }
+ pm_restore_gfp_mask();
+ error = hibernation_snapshot(data->platform_support);
+ if (!error) {
+ error = put_user(in_suspend, (int __user *)arg);
+ data->ready = !freezer_test_done && !error;
+ freezer_test_done = false;
+ }
+ break;
+
+ case SNAPSHOT_ATOMIC_RESTORE:
+ snapshot_write_finalize(&data->handle);
+ if (data->mode != O_WRONLY || !data->frozen ||
+ !snapshot_image_loaded(&data->handle)) {
+ error = -EPERM;
+ break;
+ }
+ error = hibernation_restore(data->platform_support);
+ break;
+
+ case SNAPSHOT_FREE:
+ swsusp_free();
+ memset(&data->handle, 0, sizeof(struct snapshot_handle));
+ data->ready = false;
+ /*
+ * It is necessary to thaw kernel threads here, because
+ * SNAPSHOT_CREATE_IMAGE may be invoked directly after
+ * SNAPSHOT_FREE. In that case, if kernel threads were not
+ * thawed, the preallocation of memory carried out by
+ * hibernation_snapshot() might run into problems (i.e. it
+ * might fail or even deadlock).
+ */
+ thaw_kernel_threads();
+ break;
+
+ case SNAPSHOT_PREF_IMAGE_SIZE:
+ image_size = arg;
+ break;
+
+ case SNAPSHOT_GET_IMAGE_SIZE:
+ if (!data->ready) {
+ error = -ENODATA;
+ break;
+ }
+ size = snapshot_get_image_size();
+ size <<= PAGE_SHIFT;
+ error = put_user(size, (loff_t __user *)arg);
+ break;
+
+ case SNAPSHOT_AVAIL_SWAP_SIZE:
+ size = count_swap_pages(data->swap, 1);
+ size <<= PAGE_SHIFT;
+ error = put_user(size, (loff_t __user *)arg);
+ break;
+
+ case SNAPSHOT_ALLOC_SWAP_PAGE:
+ if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
+ error = -ENODEV;
+ break;
+ }
+ offset = alloc_swapdev_block(data->swap);
+ if (offset) {
+ offset <<= PAGE_SHIFT;
+ error = put_user(offset, (loff_t __user *)arg);
+ } else {
+ error = -ENOSPC;
+ }
+ break;
+
+ case SNAPSHOT_FREE_SWAP_PAGES:
+ if (data->swap < 0 || data->swap >= MAX_SWAPFILES) {
+ error = -ENODEV;
+ break;
+ }
+ free_all_swap_pages(data->swap);
+ break;
+
+ case SNAPSHOT_S2RAM:
+ if (!data->frozen) {
+ error = -EPERM;
+ break;
+ }
+ /*
+ * Tasks are frozen and the notifiers have been called with
+ * PM_HIBERNATION_PREPARE
+ */
+ error = suspend_devices_and_enter(PM_SUSPEND_MEM);
+ data->ready = false;
+ break;
+
+ case SNAPSHOT_PLATFORM_SUPPORT:
+ data->platform_support = !!arg;
+ break;
+
+ case SNAPSHOT_POWER_OFF:
+ if (data->platform_support)
+ error = hibernation_platform_enter();
+ break;
+
+ case SNAPSHOT_SET_SWAP_AREA:
+ if (swsusp_swap_in_use()) {
+ error = -EPERM;
+ } else {
+ struct resume_swap_area swap_area;
+ dev_t swdev;
+
+ error = copy_from_user(&swap_area, (void __user *)arg,
+ sizeof(struct resume_swap_area));
+ if (error) {
+ error = -EFAULT;
+ break;
+ }
+
+ /*
+ * User space encodes device types as two-byte values,
+ * so we need to recode them
+ */
+ swdev = new_decode_dev(swap_area.dev);
+ if (swdev) {
+ offset = swap_area.offset;
+ data->swap = swap_type_of(swdev, offset, NULL);
+ if (data->swap < 0)
+ error = -ENODEV;
+ } else {
+ data->swap = -1;
+ error = -EINVAL;
+ }
+ }
+ break;
+
+ default:
+ error = -ENOTTY;
+
+ }
+
+ unlock_device_hotplug();
+ mutex_unlock(&pm_mutex);
+
+ return error;
+}
+
+#ifdef CONFIG_COMPAT
+
+struct compat_resume_swap_area {
+ compat_loff_t offset;
+ u32 dev;
+} __packed;
+
+static long
+snapshot_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ BUILD_BUG_ON(sizeof(loff_t) != sizeof(compat_loff_t));
+
+ switch (cmd) {
+ case SNAPSHOT_GET_IMAGE_SIZE:
+ case SNAPSHOT_AVAIL_SWAP_SIZE:
+ case SNAPSHOT_ALLOC_SWAP_PAGE: {
+ compat_loff_t __user *uoffset = compat_ptr(arg);
+ loff_t offset;
+ mm_segment_t old_fs;
+ int err;
+
+ old_fs = get_fs();
+ set_fs(KERNEL_DS);
+ err = snapshot_ioctl(file, cmd, (unsigned long) &offset);
+ set_fs(old_fs);
+ if (!err && put_user(offset, uoffset))
+ err = -EFAULT;
+ return err;
+ }
+
+ case SNAPSHOT_CREATE_IMAGE:
+ return snapshot_ioctl(file, cmd,
+ (unsigned long) compat_ptr(arg));
+
+ case SNAPSHOT_SET_SWAP_AREA: {
+ struct compat_resume_swap_area __user *u_swap_area =
+ compat_ptr(arg);
+ struct resume_swap_area swap_area;
+ mm_segment_t old_fs;
+ int err;
+
+ err = get_user(swap_area.offset, &u_swap_area->offset);
+ err |= get_user(swap_area.dev, &u_swap_area->dev);
+ if (err)
+ return -EFAULT;
+ old_fs = get_fs();
+ set_fs(KERNEL_DS);
+ err = snapshot_ioctl(file, SNAPSHOT_SET_SWAP_AREA,
+ (unsigned long) &swap_area);
+ set_fs(old_fs);
+ return err;
+ }
+
+ default:
+ return snapshot_ioctl(file, cmd, arg);
+ }
+}
+
+#endif /* CONFIG_COMPAT */
+
+static const struct file_operations snapshot_fops = {
+ .open = snapshot_open,
+ .release = snapshot_release,
+ .read = snapshot_read,
+ .write = snapshot_write,
+ .llseek = no_llseek,
+ .unlocked_ioctl = snapshot_ioctl,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = snapshot_compat_ioctl,
+#endif
+};
+
+static struct miscdevice snapshot_device = {
+ .minor = SNAPSHOT_MINOR,
+ .name = "snapshot",
+ .fops = &snapshot_fops,
+};
+
+static int __init snapshot_device_init(void)
+{
+ return misc_register(&snapshot_device);
+};
+
+device_initcall(snapshot_device_init);
Code Review / kvmfornfv.git / blobdiff