swsusp.c.bak

电源管理代码 基于linux2.6.10！apm方式的电源管理！很好的资料！做arm平台使用

	free_pages(p, pagedir_order);
}


/**
 *	calc_order - Determine the order of allocation needed for pagedir_save.
 *
 *	This looks tricky, but is just subtle. Please fix it some time.
 *	Since there are %nr_copy_pages worth of pages in the snapshot, we need
 *	to allocate enough contiguous space to hold 
 *		(%nr_copy_pages * sizeof(struct pbe)), 
 *	which has the saved/orig locations of the page.. 
 *
 *	SUSPEND_PD_PAGES() tells us how many pages we need to hold those 
 *	structures, then we call get_bitmask_order(), which will tell us the
 *	last bit set in the number, starting with 1. (If we need 30 pages, that
 *	is 0x0000001e in hex. The last bit is the 5th, which is the order we 
 *	would use to allocate 32 contiguous pages).
 *
 *	Since we also need to save those pages, we add the number of pages that
 *	we need to nr_copy_pages, and in case of an overflow, do the 
 *	calculation again to update the number of pages needed. 
 *
 *	With this model, we will tend to waste a lot of memory if we just cross
 *	an order boundary. Plus, the higher the order of allocation that we try
 *	to do, the more likely we are to fail in a low-memory situtation 
 *	(though	we're unlikely to get this far in such a case, since swsusp 
 *	requires half of memory to be free anyway).
 */


static void calc_order(void)
{
	int diff = 0;
	int order = 0;

	do {
		diff = get_bitmask_order(SUSPEND_PD_PAGES(nr_copy_pages)) - order;
		if (diff) {
			order += diff;
			nr_copy_pages += 1 << diff;
		}
	} while(diff);
	pagedir_order = order;
}


/**
 *	alloc_pagedir - Allocate the page directory.
 *
 *	First, determine exactly how many contiguous pages we need and
 *	allocate them.
 */

static int alloc_pagedir(void)
{
	calc_order();
	pagedir_save = (suspend_pagedir_t *)__get_free_pages(GFP_ATOMIC | __GFP_COLD,
							     pagedir_order);
	if (!pagedir_save)
		return -ENOMEM;
	memset(pagedir_save, 0, (1 << pagedir_order) * PAGE_SIZE);
	pagedir_nosave = pagedir_save;
	return 0;
}


/**
 *	alloc_image_pages - Allocate pages for the snapshot.
 *
 */

static int alloc_image_pages(void)
{
	struct pbe * p;
	int i;

	for (i = 0, p = pagedir_save; i < nr_copy_pages; i++, p++) {
		p->address = get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
		if(!p->address)
			goto Error;
		SetPageNosave(virt_to_page(p->address));
	}
	return 0;
 Error:
	do { 
		if (p->address)
			free_page(p->address);
		p->address = 0;
	} while (p-- > pagedir_save);
	return -ENOMEM;
}


/**
 *	enough_free_mem - Make sure we enough free memory to snapshot.
 *
 *	Returns TRUE or FALSE after checking the number of available 
 *	free pages.
 */

static int enough_free_mem(void)
{
	if (nr_free_pages() < (nr_copy_pages + PAGES_FOR_IO)) {
		pr_debug("swsusp: Not enough free pages: Have %d\n",
			 nr_free_pages());
		return 0;
	}
	return 1;
}


/**
 *	enough_swap - Make sure we have enough swap to save the image.
 *
 *	Returns TRUE or FALSE after checking the total amount of swap 
 *	space avaiable.
 *
 *	FIXME: si_swapinfo(&i) returns all swap devices information.
 *	We should only consider resume_device. 
 */

static int enough_swap(void)
{
	struct sysinfo i;

	si_swapinfo(&i);
	if (i.freeswap < (nr_copy_pages + PAGES_FOR_IO))  {
		pr_debug("swsusp: Not enough swap. Need %ld\n",i.freeswap);
		return 0;
	}
	return 1;
}

static int swsusp_alloc(void)
{
	int error;

	pr_debug("suspend: (pages needed: %d + %d free: %d)\n",
		 nr_copy_pages, PAGES_FOR_IO, nr_free_pages());

	pagedir_nosave = NULL;
	if (!enough_free_mem())
		return -ENOMEM;

	if (!enough_swap())
		return -ENOSPC;

	if ((error = alloc_pagedir())) {
		pr_debug("suspend: Allocating pagedir failed.\n");
		return error;
	}
	if ((error = alloc_image_pages())) {
		pr_debug("suspend: Allocating image pages failed.\n");
		swsusp_free();
		return error;
	}

	nr_copy_pages_check = nr_copy_pages;
	pagedir_order_check = pagedir_order;
	return 0;
}

int suspend_prepare_image(void)
{
	unsigned int nr_needed_pages;
	int error;

	pr_debug("swsusp: critical section: \n");
	if (save_highmem()) {
		printk(KERN_CRIT "Suspend machine: Not enough free pages for highmem\n");
		restore_highmem();
		return -ENOMEM;
	}

	drain_local_pages();
	count_data_pages();
	printk("swsusp: Need to copy %u pages\n",nr_copy_pages);
	nr_needed_pages = nr_copy_pages + PAGES_FOR_IO;

	error = swsusp_alloc();
	if (error)
		return error;
	
	/* During allocating of suspend pagedir, new cold pages may appear. 
	 * Kill them.
	 */
	drain_local_pages();
	copy_data_pages();

	/*
	 * End of critical section. From now on, we can write to memory,
	 * but we should not touch disk. This specially means we must _not_
	 * touch swap space! Except we must write out our image of course.
	 */

	printk("swsusp: critical section/: done (%d pages copied)\n", nr_copy_pages );
	return 0;
}


/* It is important _NOT_ to umount filesystems at this point. We want
 * them synced (in case something goes wrong) but we DO not want to mark
 * filesystem clean: it is not. (And it does not matter, if we resume
 * correctly, we'll mark system clean, anyway.)
 */
int swsusp_write(void)
{
	int error;
	device_resume();
	lock_swapdevices();
	error = write_suspend_image();
	/* This will unlock ignored swap devices since writing is finished */
	lock_swapdevices();
	return error;

}


extern asmlinkage int swsusp_arch_suspend(void);
extern asmlinkage int swsusp_arch_resume(void);


asmlinkage int swsusp_save(void)
{
	int error = 0;

	if ((error = swsusp_swap_check())) {
		printk(KERN_ERR "swsusp: FATAL: cannot find swap device, try "
				"swapon -a!\n");
		return error;
	}
	return suspend_prepare_image();
}

int swsusp_suspend(void)
{
	int error;
//	if ((error = arch_prepare_suspend()))
		return error;
	local_irq_disable();
	save_processor_state();
	error = swsusp_arch_suspend();
	/* Restore control flow magically appears here */
	restore_processor_state();
	restore_highmem();
	local_irq_enable();
	return error;
}


asmlinkage int swsusp_restore(void)
{
	BUG_ON (nr_copy_pages_check != nr_copy_pages);
	BUG_ON (pagedir_order_check != pagedir_order);
	
	/* Even mappings of "global" things (vmalloc) need to be fixed */
//	__flush_tlb_global();
	return 0;
}

int swsusp_resume(void)
{
	int error;
	local_irq_disable();
	/* We'll ignore saved state, but this gets preempt count (etc) right */
//	save_processor_state();
	error = swsusp_arch_resume();
	/* Code below is only ever reached in case of failure. Otherwise
	 * execution continues at place where swsusp_arch_suspend was called
         */
	BUG_ON(!error);
//	restore_processor_state();
	restore_highmem();
	local_irq_enable();
	return error;
}



/* More restore stuff */

#define does_collide(addr) does_collide_order(pagedir_nosave, addr, 0)

/*
 * Returns true if given address/order collides with any orig_address 
 */
static int __init does_collide_order(suspend_pagedir_t *pagedir, unsigned long addr,
		int order)
{
	int i;
	unsigned long addre = addr + (PAGE_SIZE<<order);
	
	for (i=0; i < nr_copy_pages; i++)
		if ((pagedir+i)->orig_address >= addr &&
			(pagedir+i)->orig_address < addre)
			return 1;

	return 0;
}

/*
 * We check here that pagedir & pages it points to won't collide with pages
 * where we're going to restore from the loaded pages later
 */
static int __init check_pagedir(void)
{
	int i;

	for(i=0; i < nr_copy_pages; i++) {
		unsigned long addr;

		do {
			addr = get_zeroed_page(GFP_ATOMIC);
			if(!addr)
				return -ENOMEM;
		} while (does_collide(addr));

		(pagedir_nosave+i)->address = addr;
	}
	return 0;
}

static int __init swsusp_pagedir_relocate(void)
{
	/*
	 * We have to avoid recursion (not to overflow kernel stack),
	 * and that's why code looks pretty cryptic 
	 */
	suspend_pagedir_t *old_pagedir = pagedir_nosave;
	void **eaten_memory = NULL;
	void **c = eaten_memory, *m, *f;
	int ret = 0;

	printk("Relocating pagedir ");

	if (!does_collide_order(old_pagedir, (unsigned long)old_pagedir, pagedir_order)) {
		printk("not necessary\n");
		return check_pagedir();
	}

	while ((m = (void *) __get_free_pages(GFP_ATOMIC, pagedir_order)) != NULL) {
		if (!does_collide_order(old_pagedir, (unsigned long)m, pagedir_order))
			break;
		eaten_memory = m;
		printk( "." ); 
		*eaten_memory = c;
		c = eaten_memory;
	}

	if (!m) {
		printk("out of memory\n");
		ret = -ENOMEM;
	} else {
		pagedir_nosave =
			memcpy(m, old_pagedir, PAGE_SIZE << pagedir_order);
	}

	c = eaten_memory;
	while (c) {
		printk(":");
		f = c;
		c = *c;
		free_pages((unsigned long)f, pagedir_order);
	}
	if (ret)
		return ret;
	printk("|\n");
	return check_pagedir();
}

/**
 *	Using bio to read from swap.
 *	This code requires a bit more work than just using buffer heads
 *	but, it is the recommended way for 2.5/2.6.
 *	The following are to signal the beginning and end of I/O. Bios
 *	finish asynchronously, while we want them to happen synchronously.
 *	A simple atomic_t, and a wait loop take care of this problem.
 */

static atomic_t io_done = ATOMIC_INIT(0);

static void start_io(void)
{
	atomic_set(&io_done,1);
}

static int end_io(struct bio * bio, unsigned int num, int err)
{
	atomic_set(&io_done,0);
	return 0;
}

static void wait_io(void)
{
	while(atomic_read(&io_done))
		io_schedule();
}


static struct block_device * resume_bdev;

/**
 *	submit - submit BIO request.
 *	@rw:	READ or WRITE.
 *	@off	physical offset of page.
 *	@page:	page we're reading or writing.
 *
 *	Straight from the textbook - allocate and initialize the bio.
 *	If we're writing, make sure the page is marked as dirty.
 *	Then submit it and wait.
 */

static int submit(int rw, pgoff_t page_off, void * page)
{
	int error = 0;
	struct bio * bio;

	bio = bio_alloc(GFP_ATOMIC, 1);
	if (!bio)
		return -ENOMEM;
	bio->bi_sector = page_off * (PAGE_SIZE >> 9);
	bio_get(bio);
	bio->bi_bdev = resume_bdev;
	bio->bi_end_io = end_io;

	if (bio_add_page(bio, virt_to_page(page), PAGE_SIZE, 0) < PAGE_SIZE) {
		printk("swsusp: ERROR: adding page to bio at %ld\n",page_off);
		error = -EFAULT;
		goto Done;
	}

	if (rw == WRITE)
		bio_set_pages_dirty(bio);
	start_io();
	submit_bio(rw | (1 << BIO_RW_SYNC), bio);
	wait_io();
 Done:
	bio_put(bio);
	return error;
}

int bio_read_page(pgoff_t page_off, void * page)
{
	return submit(READ, page_off, page);
}

int bio_write_page(pgoff_t page_off, void * page)
{
	return submit(WRITE, page_off, page);
}

/*
 * Sanity check if this image makes sense with this kernel/swap context
 * I really don't think that it's foolproof but more than nothing..
 */

static const char * __init sanity_check(void)
{
	dump_info();
	if(swsusp_info.version_code != LINUX_VERSION_CODE)
		return "kernel version";
	if(swsusp_info.num_physpages != num_physpages)
		return "memory size";
	if (strcmp(swsusp_info.uts.sysname,system_utsname.sysname))
		return "system type";
	if (strcmp(swsusp_info.uts.release,system_utsname.release))
		return "kernel release";
	if (strcmp(swsusp_info.uts.version,system_utsname.version))
		return "version";
	if (strcmp(swsusp_info.uts.machine,system_utsname.machine))
		return "machine";
	if(swsusp_info.cpus != num_online_cpus())
		return "number of cpus";
	return NULL;
}


static int __init check_header(void)
{
	const char * reason = NULL;
	int error;

	if ((error = bio_read_page(swp_offset(swsusp_header.swsusp_info), &swsusp_info)))
		return error;

 	/* Is this same machine? */
	if ((reason = sanity_check())) {
		printk(KERN_ERR "swsusp: Resume mismatch: %s\n",reason);
		return -EPERM;
	}
	nr_copy_pages = swsusp_info.image_pages;
	return error;
}

static int __init check_sig(void)
{
	int error;

	memset(&swsusp_header, 0, sizeof(swsusp_header));
	if ((error = bio_read_page(0, &swsusp_header)))
		return error;
	if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) {
		memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10);

		/*
		 * Reset swap signature now.
		 */
		error = bio_write_page(0, &swsusp_header);
	} else { 
		pr_debug(KERN_ERR "swsusp: Suspend partition has wrong signature?\n");
		return -EINVAL;
	}
	if (!error)
		pr_debug("swsusp: Signature found, resuming\n");
	return error;
}

/**
 *	swsusp_read_data - Read image pages from swap.
 *
 *	You do not need to check for overlaps, check_pagedir()
 *	already did that.
 */

static int __init data_read(void)
{
	struct pbe * p;
	int error;
	int i;
	int mod = nr_copy_pages / 100;

	if (!mod)
		mod = 1;

	if ((error = swsusp_pagedir_relocate()))
		return error;

	printk( "Reading image data (%d pages):     ", nr_copy_pages );
	for(i = 0, p = pagedir_nosave; i < nr_copy_pages && !error; i++, p++) {
		if (!(i%mod))
			printk( "\b\b\b\b%3d%%", i / mod );
		error = bio_read_page(swp_offset(p->swap_address),
				  (void *)p->address);
	}
	printk(" %d done.\n",i);
	return error;

}

extern dev_t __init name_to_dev_t(const char *line);

static int __init read_pagedir(void)
{
	unsigned long addr;
	int i, n = swsusp_info.pagedir_pages;
	int error = 0;

	pagedir_order = get_bitmask_order(n);

	addr =__get_free_pages(GFP_ATOMIC, pagedir_order);
	if (!addr)
		return -ENOMEM;
	pagedir_nosave = (struct pbe *)addr;

	pr_debug("pmdisk: Reading pagedir (%d Pages)\n",n);

	for (i = 0; i < n && !error; i++, addr += PAGE_SIZE) {
		unsigned long offset = swp_offset(swsusp_info.pagedir[i]);
		if (offset)
			error = bio_read_page(offset, (void *)addr);
		else
			error = -EFAULT;
	}
	if (error)
		free_pages((unsigned long)pagedir_nosave, pagedir_order);
	return error;
}

static int __init read_suspend_image(void)
{
	int error = 0;

	if ((error = check_sig()))
		return error;
	if ((error = check_header()))
		return error;
	if ((error = read_pagedir()))
		return error;
	if ((error = data_read()))
		free_pages((unsigned long)pagedir_nosave, pagedir_order);
	return error;
}

/**
 *	pmdisk_read - Read saved image from swap.
 */

int __init swsusp_read(void)
{
	int error;

	if (!strlen(resume_file))
		return -ENOENT;

	resume_device = name_to_dev_t(resume_file);
	pr_debug("swsusp: Resume From Partition: %s\n", resume_file);

	resume_bdev = open_by_devnum(resume_device, FMODE_READ);
	if (!IS_ERR(resume_bdev)) {
		set_blocksize(resume_bdev, PAGE_SIZE);
		error = read_suspend_image();
		blkdev_put(resume_bdev);
	} else
		error = PTR_ERR(resume_bdev);

	if (!error)
		pr_debug("Reading resume file was successful\n");
	else
		pr_debug("pmdisk: Error %d resuming\n", error);
	return error;
}