aboutsummaryrefslogtreecommitdiff
path: root/kernel/power/swsusp.c
blob: 8ef677ea0ceae150ad4017ee77e485073ff995b9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
/*
 * linux/kernel/power/swsusp.c
 *
 * This file provides code to write suspend image to swap and read it back.
 *
 * Copyright (C) 1998-2001 Gabor Kuti <seasons@fornax.hu>
 * Copyright (C) 1998,2001-2005 Pavel Machek <pavel@suse.cz>
 *
 * This file is released under the GPLv2.
 *
 * I'd like to thank the following people for their work:
 *
 * Pavel Machek <pavel@ucw.cz>:
 * Modifications, defectiveness pointing, being with me at the very beginning,
 * suspend to swap space, stop all tasks. Port to 2.4.18-ac and 2.5.17.
 *
 * Steve Doddi <dirk@loth.demon.co.uk>:
 * Support the possibility of hardware state restoring.
 *
 * Raph <grey.havens@earthling.net>:
 * Support for preserving states of network devices and virtual console
 * (including X and svgatextmode)
 *
 * Kurt Garloff <garloff@suse.de>:
 * Straightened the critical function in order to prevent compilers from
 * playing tricks with local variables.
 *
 * Andreas Mohr <a.mohr@mailto.de>
 *
 * Alex Badea <vampire@go.ro>:
 * Fixed runaway init
 *
 * Rafael J. Wysocki <rjw@sisk.pl>
 * Reworked the freeing of memory and the handling of swap
 *
 * More state savers are welcome. Especially for the scsi layer...
 *
 * For TODOs,FIXMEs also look in Documentation/power/swsusp.txt
 */

#include <linux/mm.h>
#include <linux/suspend.h>
#include <linux/spinlock.h>
#include <linux/kernel.h>
#include <linux/major.h>
#include <linux/swap.h>
#include <linux/pm.h>
#include <linux/swapops.h>
#include <linux/bootmem.h>
#include <linux/syscalls.h>
#include <linux/highmem.h>

#include "power.h"

/*
 * Preferred image size in bytes (tunable via /sys/power/image_size).
 * When it is set to N, swsusp will do its best to ensure the image
 * size will not exceed N bytes, but if that is impossible, it will
 * try to create the smallest image possible.
 */
unsigned long image_size = 500 * 1024 * 1024;

int in_suspend __nosavedata = 0;

#ifdef CONFIG_HIGHMEM
unsigned int count_highmem_pages(void);
int save_highmem(void);
int restore_highmem(void);
#else
static inline int save_highmem(void) { return 0; }
static inline int restore_highmem(void) { return 0; }
static inline unsigned int count_highmem_pages(void) { return 0; }
#endif

/**
 *	The following functions are used for tracing the allocated
 *	swap pages, so that they can be freed in case of an error.
 *
 *	The functions operate on a linked bitmap structure defined
 *	in power.h
 */

void free_bitmap(struct bitmap_page *bitmap)
{
	struct bitmap_page *bp;

	while (bitmap) {
		bp = bitmap->next;
		free_page((unsigned long)bitmap);
		bitmap = bp;
	}
}

struct bitmap_page *alloc_bitmap(unsigned int nr_bits)
{
	struct bitmap_page *bitmap, *bp;
	unsigned int n;

	if (!nr_bits)
		return NULL;

	bitmap = (struct bitmap_page *)get_zeroed_page(GFP_KERNEL);
	bp = bitmap;
	for (n = BITMAP_PAGE_BITS; n < nr_bits; n += BITMAP_PAGE_BITS) {
		bp->next = (struct bitmap_page *)get_zeroed_page(GFP_KERNEL);
		bp = bp->next;
		if (!bp) {
			free_bitmap(bitmap);
			return NULL;
		}
	}
	return bitmap;
}

static int bitmap_set(struct bitmap_page *bitmap, unsigned long bit)
{
	unsigned int n;

	n = BITMAP_PAGE_BITS;
	while (bitmap && n <= bit) {
		n += BITMAP_PAGE_BITS;
		bitmap = bitmap->next;
	}
	if (!bitmap)
		return -EINVAL;
	n -= BITMAP_PAGE_BITS;
	bit -= n;
	n = 0;
	while (bit >= BITS_PER_CHUNK) {
		bit -= BITS_PER_CHUNK;
		n++;
	}
	bitmap->chunks[n] |= (1UL << bit);
	return 0;
}

unsigned long alloc_swap_page(int swap, struct bitmap_page *bitmap)
{
	unsigned long offset;

	offset = swp_offset(get_swap_page_of_type(swap));
	if (offset) {
		if (bitmap_set(bitmap, offset)) {
			swap_free(swp_entry(swap, offset));
			offset = 0;
		}
	}
	return offset;
}

void free_all_swap_pages(int swap, struct bitmap_page *bitmap)
{
	unsigned int bit, n;
	unsigned long test;

	bit = 0;
	while (bitmap) {
		for (n = 0; n < BITMAP_PAGE_CHUNKS; n++)
			for (test = 1UL; test; test <<= 1) {
				if (bitmap->chunks[n] & test)
					swap_free(swp_entry(swap, bit));
				bit++;
			}
		bitmap = bitmap->next;
	}
}

/**
 *	swsusp_shrink_memory -  Try to free as much memory as needed
 *
 *	... but do not OOM-kill anyone
 *
 *	Notice: all userland should be stopped before it is called, or
 *	livelock is possible.
 */

#define SHRINK_BITE	10000
static inline unsigned long __shrink_memory(long tmp)
{
	if (tmp > SHRINK_BITE)
		tmp = SHRINK_BITE;
	return shrink_all_memory(tmp);
}

int swsusp_shrink_memory(void)
{
	long size, tmp;
	struct zone *zone;
	unsigned long pages = 0;
	unsigned int i = 0;
	char *p = "-\\|/";

	printk("Shrinking memory...  ");
	do {
		size = 2 * count_highmem_pages();
		size += size / 50 + count_data_pages() + PAGES_FOR_IO;
		tmp = size;
		for_each_zone (zone)
			if (!is_highmem(zone) && populated_zone(zone)) {
				tmp -= zone->free_pages;
				tmp += zone->lowmem_reserve[ZONE_NORMAL];
				tmp += snapshot_additional_pages(zone);
			}
		if (tmp > 0) {
			tmp = __shrink_memory(tmp);
			if (!tmp)
				return -ENOMEM;
			pages += tmp;
		} else if (size > image_size / PAGE_SIZE) {
			tmp = __shrink_memory(size - (image_size / PAGE_SIZE));
			pages += tmp;
		}
		printk("\b%c", p[i++%4]);
	} while (tmp > 0);
	printk("\bdone (%lu pages freed)\n", pages);

	return 0;
}

int swsusp_suspend(void)
{
	int error;

	if ((error = arch_prepare_suspend()))
		return error;
	local_irq_disable();
	/* At this point, device_suspend() has been called, but *not*
	 * device_power_down(). We *must* device_power_down() now.
	 * Otherwise, drivers for some devices (e.g. interrupt controllers)
	 * become desynchronized with the actual state of the hardware
	 * at resume time, and evil weirdness ensues.
	 */
	if ((error = device_power_down(PMSG_FREEZE))) {
		printk(KERN_ERR "Some devices failed to power down, aborting suspend\n");
		goto Enable_irqs;
	}

	if ((error = save_highmem())) {
		printk(KERN_ERR "swsusp: Not enough free pages for highmem\n");
		goto Restore_highmem;
	}

	save_processor_state();
	if ((error = swsusp_arch_suspend()))
		printk(KERN_ERR "Error %d suspending\n", error);
	/* Restore control flow magically appears here */
	restore_processor_state();
Restore_highmem:
	restore_highmem();
	device_power_up();
Enable_irqs:
	local_irq_enable();
	return error;
}

int swsusp_resume(void)
{
	int error;
	local_irq_disable();
	if (device_power_down(PMSG_FREEZE))
		printk(KERN_ERR "Some devices failed to power down, very bad\n");
	/* 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);
	/* The only reason why swsusp_arch_resume() can fail is memory being
	 * very tight, so we have to free it as soon as we can to avoid
	 * subsequent failures
	 */
	swsusp_free();
	restore_processor_state();
	restore_highmem();
	touch_softlockup_watchdog();
	device_power_up();
	local_irq_enable();
	return error;
}