/* * 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 * Copyright (C) 1998,2001-2005 Pavel Machek * * This file is released under the GPLv2. * * I'd like to thank the following people for their work: * * Pavel Machek : * 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 : * Support the possibility of hardware state restoring. * * Raph : * Support for preserving states of network devices and virtual console * (including X and svgatextmode) * * Kurt Garloff : * Straightened the critical function in order to prevent compilers from * playing tricks with local variables. * * Andreas Mohr * * Alex Badea : * Fixed runaway init * * Rafael J. Wysocki * 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 #include #include #include #include #include #include #include #include #include #include #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 int save_highmem(void) { return 0; } static int restore_highmem(void) { return 0; } static 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 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(); size += (size + PBES_PER_PAGE - 1) / PBES_PER_PAGE + PAGES_FOR_IO; tmp = size; for_each_zone (zone) if (!is_highmem(zone)) tmp -= zone->free_pages; if (tmp > 0) { tmp = shrink_all_memory(SHRINK_BITE); if (!tmp) return -ENOMEM; pages += tmp; } else if (size > image_size / PAGE_SIZE) { tmp = shrink_all_memory(SHRINK_BITE); 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; }