diff options
| -rw-r--r-- | Documentation/power/userland-swsusp.txt | 149 | ||||
| -rw-r--r-- | init/do_mounts_initrd.c | 1 | ||||
| -rw-r--r-- | kernel/power/Makefile | 2 | ||||
| -rw-r--r-- | kernel/power/power.h | 14 | ||||
| -rw-r--r-- | kernel/power/snapshot.c | 9 | ||||
| -rw-r--r-- | kernel/power/user.c | 301 | ||||
| -rw-r--r-- | mm/swapfile.c | 6 |
7 files changed, 475 insertions, 7 deletions
diff --git a/Documentation/power/userland-swsusp.txt b/Documentation/power/userland-swsusp.txt new file mode 100644 index 0000000..9405822 --- /dev/null +++ b/Documentation/power/userland-swsusp.txt @@ -0,0 +1,149 @@ +Documentation for userland software suspend interface + (C) 2006 Rafael J. Wysocki <rjw@sisk.pl> + +First, the warnings at the beginning of swsusp.txt still apply. + +Second, you should read the FAQ in swsusp.txt _now_ if you have not +done it already. + +Now, to use the userland interface for software suspend you need special +utilities that will read/write the system memory snapshot from/to the +kernel. Such utilities are available, for example, from +<http://www.sisk.pl/kernel/utilities/suspend>. You may want to have +a look at them if you are going to develop your own suspend/resume +utilities. + +The interface consists of a character device providing the open(), +release(), read(), and write() operations as well as several ioctl() +commands defined in kernel/power/power.h. The major and minor +numbers of the device are, respectively, 10 and 231, and they can +be read from /sys/class/misc/snapshot/dev. + +The device can be open either for reading or for writing. If open for +reading, it is considered to be in the suspend mode. Otherwise it is +assumed to be in the resume mode. The device cannot be open for reading +and writing. It is also impossible to have the device open more than once +at a time. + +The ioctl() commands recognized by the device are: + +SNAPSHOT_FREEZE - freeze user space processes (the current process is + not frozen); this is required for SNAPSHOT_ATOMIC_SNAPSHOT + and SNAPSHOT_ATOMIC_RESTORE to succeed + +SNAPSHOT_UNFREEZE - thaw user space processes frozen by SNAPSHOT_FREEZE + +SNAPSHOT_ATOMIC_SNAPSHOT - create a snapshot of the system memory; the + last argument of ioctl() should be a pointer to an int variable, + the value of which will indicate whether the call returned after + creating the snapshot (1) or after restoring the system memory state + from it (0) (after resume the system finds itself finishing the + SNAPSHOT_ATOMIC_SNAPSHOT ioctl() again); after the snapshot + has been created the read() operation can be used to transfer + it out of the kernel + +SNAPSHOT_ATOMIC_RESTORE - restore the system memory state from the + uploaded snapshot image; before calling it you should transfer + the system memory snapshot back to the kernel using the write() + operation; this call will not succeed if the snapshot + image is not available to the kernel + +SNAPSHOT_FREE - free memory allocated for the snapshot image + +SNAPSHOT_SET_IMAGE_SIZE - set the preferred maximum size of the image + (the kernel will do its best to ensure the image size will not exceed + this number, but if it turns out to be impossible, the kernel will + create the smallest image possible) + +SNAPSHOT_AVAIL_SWAP - return the amount of available swap in bytes (the last + argument should be a pointer to an unsigned int variable that will + contain the result if the call is successful). + +SNAPSHOT_GET_SWAP_PAGE - allocate a swap page from the resume partition + (the last argument should be a pointer to a loff_t variable that + will contain the swap page offset if the call is successful) + +SNAPSHOT_FREE_SWAP_PAGES - free all swap pages allocated with + SNAPSHOT_GET_SWAP_PAGE + +SNAPSHOT_SET_SWAP_FILE - set the resume partition (the last ioctl() argument + should specify the device's major and minor numbers in the old + two-byte format, as returned by the stat() function in the .st_rdev + member of the stat structure); it is recommended to always use this + call, because the code to set the resume partition could be removed from + future kernels + +The device's read() operation can be used to transfer the snapshot image from +the kernel. It has the following limitations: +- you cannot read() more than one virtual memory page at a time +- read()s accross page boundaries are impossible (ie. if ypu read() 1/2 of + a page in the previous call, you will only be able to read() + _at_ _most_ 1/2 of the page in the next call) + +The device's write() operation is used for uploading the system memory snapshot +into the kernel. It has the same limitations as the read() operation. + +The release() operation frees all memory allocated for the snapshot image +and all swap pages allocated with SNAPSHOT_GET_SWAP_PAGE (if any). +Thus it is not necessary to use either SNAPSHOT_FREE or +SNAPSHOT_FREE_SWAP_PAGES before closing the device (in fact it will also +unfreeze user space processes frozen by SNAPSHOT_UNFREEZE if they are +still frozen when the device is being closed). + +Currently it is assumed that the userland utilities reading/writing the +snapshot image from/to the kernel will use a swap parition, called the resume +partition, as storage space. However, this is not really required, as they +can use, for example, a special (blank) suspend partition or a file on a partition +that is unmounted before SNAPSHOT_ATOMIC_SNAPSHOT and mounted afterwards. + +These utilities SHOULD NOT make any assumptions regarding the ordering of +data within the snapshot image, except for the image header that MAY be +assumed to start with an swsusp_info structure, as specified in +kernel/power/power.h. This structure MAY be used by the userland utilities +to obtain some information about the snapshot image, such as the size +of the snapshot image, including the metadata and the header itself, +contained in the .size member of swsusp_info. + +The snapshot image MUST be written to the kernel unaltered (ie. all of the image +data, metadata and header MUST be written in _exactly_ the same amount, form +and order in which they have been read). Otherwise, the behavior of the +resumed system may be totally unpredictable. + +While executing SNAPSHOT_ATOMIC_RESTORE the kernel checks if the +structure of the snapshot image is consistent with the information stored +in the image header. If any inconsistencies are detected, +SNAPSHOT_ATOMIC_RESTORE will not succeed. Still, this is not a fool-proof +mechanism and the userland utilities using the interface SHOULD use additional +means, such as checksums, to ensure the integrity of the snapshot image. + +The suspending and resuming utilities MUST lock themselves in memory, +preferrably using mlockall(), before calling SNAPSHOT_FREEZE. + +The suspending utility MUST check the value stored by SNAPSHOT_ATOMIC_SNAPSHOT +in the memory location pointed to by the last argument of ioctl() and proceed +in accordance with it: +1. If the value is 1 (ie. the system memory snapshot has just been + created and the system is ready for saving it): + (a) The suspending utility MUST NOT close the snapshot device + _unless_ the whole suspend procedure is to be cancelled, in + which case, if the snapshot image has already been saved, the + suspending utility SHOULD destroy it, preferrably by zapping + its header. If the suspend is not to be cancelled, the + system MUST be powered off or rebooted after the snapshot + image has been saved. + (b) The suspending utility SHOULD NOT attempt to perform any + file system operations (including reads) on the file systems + that were mounted before SNAPSHOT_ATOMIC_SNAPSHOT has been + called. However, it MAY mount a file system that was not + mounted at that time and perform some operations on it (eg. + use it for saving the image). +2. If the value is 0 (ie. the system state has just been restored from + the snapshot image), the suspending utility MUST close the snapshot + device. Afterwards it will be treated as a regular userland process, + so it need not exit. + +The resuming utility SHOULD NOT attempt to mount any file systems that could +be mounted before suspend and SHOULD NOT attempt to perform any operations +involving such file systems. + +For details, please refer to the source code. diff --git a/init/do_mounts_initrd.c b/init/do_mounts_initrd.c index a05cabd..405f903 100644 --- a/init/do_mounts_initrd.c +++ b/init/do_mounts_initrd.c @@ -56,6 +56,7 @@ static void __init handle_initrd(void) sys_chroot("."); mount_devfs_fs (); + current->flags |= PF_NOFREEZE; pid = kernel_thread(do_linuxrc, "/linuxrc", SIGCHLD); if (pid > 0) { while (pid != sys_wait4(-1, NULL, 0, NULL)) diff --git a/kernel/power/Makefile b/kernel/power/Makefile index bb91a06..8d0af3d 100644 --- a/kernel/power/Makefile +++ b/kernel/power/Makefile @@ -5,7 +5,7 @@ endif obj-y := main.o process.o console.o obj-$(CONFIG_PM_LEGACY) += pm.o -obj-$(CONFIG_SOFTWARE_SUSPEND) += swsusp.o disk.o snapshot.o swap.o +obj-$(CONFIG_SOFTWARE_SUSPEND) += swsusp.o disk.o snapshot.o swap.o user.o obj-$(CONFIG_SUSPEND_SMP) += smp.o diff --git a/kernel/power/power.h b/kernel/power/power.h index 5d1abff..42c431c 100644 --- a/kernel/power/power.h +++ b/kernel/power/power.h @@ -8,6 +8,7 @@ struct swsusp_info { int cpus; unsigned long image_pages; unsigned long pages; + unsigned long size; } __attribute__((aligned(PAGE_SIZE))); @@ -65,6 +66,19 @@ extern int snapshot_read_next(struct snapshot_handle *handle, size_t count); extern int snapshot_write_next(struct snapshot_handle *handle, size_t count); int snapshot_image_loaded(struct snapshot_handle *handle); +#define SNAPSHOT_IOC_MAGIC '3' +#define SNAPSHOT_FREEZE _IO(SNAPSHOT_IOC_MAGIC, 1) +#define SNAPSHOT_UNFREEZE _IO(SNAPSHOT_IOC_MAGIC, 2) +#define SNAPSHOT_ATOMIC_SNAPSHOT _IOW(SNAPSHOT_IOC_MAGIC, 3, void *) +#define SNAPSHOT_ATOMIC_RESTORE _IO(SNAPSHOT_IOC_MAGIC, 4) +#define SNAPSHOT_FREE _IO(SNAPSHOT_IOC_MAGIC, 5) +#define SNAPSHOT_SET_IMAGE_SIZE _IOW(SNAPSHOT_IOC_MAGIC, 6, unsigned long) +#define SNAPSHOT_AVAIL_SWAP _IOR(SNAPSHOT_IOC_MAGIC, 7, void *) +#define SNAPSHOT_GET_SWAP_PAGE _IOR(SNAPSHOT_IOC_MAGIC, 8, void *) +#define SNAPSHOT_FREE_SWAP_PAGES _IO(SNAPSHOT_IOC_MAGIC, 9) +#define SNAPSHOT_SET_SWAP_FILE _IOW(SNAPSHOT_IOC_MAGIC, 10, unsigned int) +#define SNAPSHOT_IOC_MAXNR 10 + /** * The bitmap is used for tracing allocated swap pages * diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index cc34943..0036955 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -37,6 +37,7 @@ struct pbe *pagedir_nosave; static unsigned int nr_copy_pages; static unsigned int nr_meta_pages; +static unsigned long *buffer; #ifdef CONFIG_HIGHMEM unsigned int count_highmem_pages(void) @@ -389,7 +390,7 @@ struct pbe *alloc_pagedir(unsigned int nr_pages, gfp_t gfp_mask, int safe_needed free_pagedir(pblist); pblist = NULL; } else - create_pbe_list(pblist, nr_pages); + create_pbe_list(pblist, nr_pages); return pblist; } @@ -418,6 +419,7 @@ void swsusp_free(void) nr_copy_pages = 0; nr_meta_pages = 0; pagedir_nosave = NULL; + buffer = NULL; } @@ -523,6 +525,8 @@ static void init_header(struct swsusp_info *info) info->cpus = num_online_cpus(); info->image_pages = nr_copy_pages; info->pages = nr_copy_pages + nr_meta_pages + 1; + info->size = info->pages; + info->size <<= PAGE_SHIFT; } /** @@ -568,8 +572,6 @@ static inline struct pbe *pack_orig_addresses(unsigned long *buf, struct pbe *pb int snapshot_read_next(struct snapshot_handle *handle, size_t count) { - static unsigned long *buffer; - if (handle->page > nr_meta_pages + nr_copy_pages) return 0; if (!buffer) { @@ -774,7 +776,6 @@ static int create_image(struct snapshot_handle *handle) int snapshot_write_next(struct snapshot_handle *handle, size_t count) { - static unsigned long *buffer; int error = 0; if (handle->prev && handle->page > nr_meta_pages + nr_copy_pages) diff --git a/kernel/power/user.c b/kernel/power/user.c new file mode 100644 index 0000000..8cabc40 --- /dev/null +++ b/kernel/power/user.c @@ -0,0 +1,301 @@ +/* + * 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/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 <asm/uaccess.h> + +#include "power.h" + +#define SNAPSHOT_MINOR 231 + +static struct snapshot_data { + struct snapshot_handle handle; + int swap; + struct bitmap_page *bitmap; + int mode; + char frozen; + char ready; +} snapshot_state; + +static atomic_t device_available = ATOMIC_INIT(1); + +static int snapshot_open(struct inode *inode, struct file *filp) +{ + struct snapshot_data *data; + + if (!atomic_add_unless(&device_available, -1, 0)) + return -EBUSY; + + if ((filp->f_flags & O_ACCMODE) == O_RDWR) + return -ENOSYS; + + 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) { + data->swap = swsusp_resume_device ? swap_type_of(swsusp_resume_device) : -1; + data->mode = O_RDONLY; + } else { + data->swap = -1; + data->mode = O_WRONLY; + } + data->bitmap = NULL; + data->frozen = 0; + data->ready = 0; + + return 0; +} + +static int snapshot_release(struct inode *inode, struct file *filp) +{ + struct snapshot_data *data; + + swsusp_free(); + data = filp->private_data; + free_all_swap_pages(data->swap, data->bitmap); + free_bitmap(data->bitmap); + if (data->frozen) { + down(&pm_sem); + thaw_processes(); + enable_nonboot_cpus(); + up(&pm_sem); + } + atomic_inc(&device_available); + 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; + + data = filp->private_data; + res = snapshot_read_next(&data->handle, count); + if (res > 0) { + if (copy_to_user(buf, data_of(data->handle), res)) + res = -EFAULT; + else + *offp = data->handle.offset; + } + 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; + + data = filp->private_data; + res = snapshot_write_next(&data->handle, count); + if (res > 0) { + if (copy_from_user(data_of(data->handle), buf, res)) + res = -EFAULT; + else + *offp = data->handle.offset; + } + return res; +} + +static int snapshot_ioctl(struct inode *inode, struct file *filp, + unsigned int cmd, unsigned long arg) +{ + int error = 0; + struct snapshot_data *data; + loff_t offset, avail; + + 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; + + data = filp->private_data; + + switch (cmd) { + + case SNAPSHOT_FREEZE: + if (data->frozen) + break; + sys_sync(); + down(&pm_sem); + pm_prepare_console(); + disable_nonboot_cpus(); + if (freeze_processes()) { + thaw_processes(); + enable_nonboot_cpus(); + pm_restore_console(); + error = -EBUSY; + } + up(&pm_sem); + if (!error) + data->frozen = 1; + break; + + case SNAPSHOT_UNFREEZE: + if (!data->frozen) + break; + down(&pm_sem); + thaw_processes(); + enable_nonboot_cpus(); + pm_restore_console(); + up(&pm_sem); + data->frozen = 0; + break; + + case SNAPSHOT_ATOMIC_SNAPSHOT: + if (data->mode != O_RDONLY || !data->frozen || data->ready) { + error = -EPERM; + break; + } + down(&pm_sem); + /* Free memory before shutting down devices. */ + error = swsusp_shrink_memory(); + if (!error) { + error = device_suspend(PMSG_FREEZE); + if (!error) { + in_suspend = 1; + error = swsusp_suspend(); + device_resume(); + } + } + up(&pm_sem); + if (!error) + error = put_user(in_suspend, (unsigned int __user *)arg); + if (!error) + data->ready = 1; + break; + + case SNAPSHOT_ATOMIC_RESTORE: + if (data->mode != O_WRONLY || !data->frozen || + !snapshot_image_loaded(&data->handle)) { + error = -EPERM; + break; + } + down(&pm_sem); + pm_prepare_console(); + error = device_suspend(PMSG_FREEZE); + if (!error) { + error = swsusp_resume(); + device_resume(); + } + pm_restore_console(); + up(&pm_sem); + break; + + case SNAPSHOT_FREE: + swsusp_free(); + memset(&data->handle, 0, sizeof(struct snapshot_handle)); + data->ready = 0; + break; + + case SNAPSHOT_SET_IMAGE_SIZE: + image_size = arg; + break; + + case SNAPSHOT_AVAIL_SWAP: + avail = count_swap_pages(data->swap, 1); + avail <<= PAGE_SHIFT; + error = put_user(avail, (loff_t __user *)arg); + break; + + case SNAPSHOT_GET_SWAP_PAGE: + if (data->swap < 0 || data->swap >= MAX_SWAPFILES) { + error = -ENODEV; + break; + } + if (!data->bitmap) { + data->bitmap = alloc_bitmap(count_swap_pages(data->swap, 0)); + if (!data->bitmap) { + error = -ENOMEM; + break; + } + } + offset = alloc_swap_page(data->swap, data->bitmap); + 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, data->bitmap); + free_bitmap(data->bitmap); + data->bitmap = NULL; + break; + + case SNAPSHOT_SET_SWAP_FILE: + if (!data->bitmap) { + /* + * User space encodes device types as two-byte values, + * so we need to recode them + */ + if (old_decode_dev(arg)) { + data->swap = swap_type_of(old_decode_dev(arg)); + if (data->swap < 0) + error = -ENODEV; + } else { + data->swap = -1; + error = -EINVAL; + } + } else { + error = -EPERM; + } + break; + + default: + error = -ENOTTY; + + } + + return error; +} + +static struct file_operations snapshot_fops = { + .open = snapshot_open, + .release = snapshot_release, + .read = snapshot_read, + .write = snapshot_write, + .llseek = no_llseek, + .ioctl = snapshot_ioctl, +}; + +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); diff --git a/mm/swapfile.c b/mm/swapfile.c index 4d11f9d..39aa9d1 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -428,14 +428,16 @@ int swap_type_of(dev_t device) { int i; - if (!device) - return -EINVAL; spin_lock(&swap_lock); for (i = 0; i < nr_swapfiles; i++) { struct inode *inode; if (!(swap_info[i].flags & SWP_WRITEOK)) continue; + if (!device) { + spin_unlock(&swap_lock); + return i; + } inode = swap_info->swap_file->f_dentry->d_inode; if (S_ISBLK(inode->i_mode) && device == MKDEV(imajor(inode), iminor(inode))) { |
