![Rafael J. Wysocki](/assets/img/avatar_default.png)
The changes made by this patch are necessary for the pagedir relocation simplification in the next patch. Additionally, these changes allow us to drop check_pagedir() and make get_safe_page() be a one-line wrapper around alloc_image_page() (get_safe_page() goes to snapshot.c, because alloc_image_page() is static and it does not make sense to export it). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
469 lines
11 KiB
C
469 lines
11 KiB
C
/*
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* linux/kernel/power/snapshot.c
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*
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* This file provide system snapshot/restore functionality.
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*
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* Copyright (C) 1998-2005 Pavel Machek <pavel@suse.cz>
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*
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* This file is released under the GPLv2, and is based on swsusp.c.
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*
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*/
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/suspend.h>
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#include <linux/smp_lock.h>
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#include <linux/delay.h>
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#include <linux/bitops.h>
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#include <linux/spinlock.h>
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#include <linux/kernel.h>
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#include <linux/pm.h>
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#include <linux/device.h>
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#include <linux/bootmem.h>
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#include <linux/syscalls.h>
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#include <linux/console.h>
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#include <linux/highmem.h>
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#include <asm/uaccess.h>
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#include <asm/mmu_context.h>
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#include <asm/pgtable.h>
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#include <asm/tlbflush.h>
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#include <asm/io.h>
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#include "power.h"
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#ifdef CONFIG_HIGHMEM
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struct highmem_page {
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char *data;
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struct page *page;
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struct highmem_page *next;
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};
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static struct highmem_page *highmem_copy;
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static int save_highmem_zone(struct zone *zone)
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{
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unsigned long zone_pfn;
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mark_free_pages(zone);
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for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
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struct page *page;
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struct highmem_page *save;
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void *kaddr;
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unsigned long pfn = zone_pfn + zone->zone_start_pfn;
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if (!(pfn%1000))
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printk(".");
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if (!pfn_valid(pfn))
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continue;
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page = pfn_to_page(pfn);
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/*
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* This condition results from rvmalloc() sans vmalloc_32()
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* and architectural memory reservations. This should be
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* corrected eventually when the cases giving rise to this
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* are better understood.
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*/
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if (PageReserved(page)) {
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printk("highmem reserved page?!\n");
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continue;
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}
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BUG_ON(PageNosave(page));
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if (PageNosaveFree(page))
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continue;
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save = kmalloc(sizeof(struct highmem_page), GFP_ATOMIC);
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if (!save)
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return -ENOMEM;
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save->next = highmem_copy;
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save->page = page;
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save->data = (void *) get_zeroed_page(GFP_ATOMIC);
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if (!save->data) {
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kfree(save);
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return -ENOMEM;
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}
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kaddr = kmap_atomic(page, KM_USER0);
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memcpy(save->data, kaddr, PAGE_SIZE);
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kunmap_atomic(kaddr, KM_USER0);
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highmem_copy = save;
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}
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return 0;
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}
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static int save_highmem(void)
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{
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struct zone *zone;
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int res = 0;
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pr_debug("swsusp: Saving Highmem\n");
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for_each_zone (zone) {
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if (is_highmem(zone))
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res = save_highmem_zone(zone);
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if (res)
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return res;
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}
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return 0;
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}
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int restore_highmem(void)
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{
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printk("swsusp: Restoring Highmem\n");
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while (highmem_copy) {
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struct highmem_page *save = highmem_copy;
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void *kaddr;
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highmem_copy = save->next;
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kaddr = kmap_atomic(save->page, KM_USER0);
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memcpy(kaddr, save->data, PAGE_SIZE);
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kunmap_atomic(kaddr, KM_USER0);
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free_page((long) save->data);
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kfree(save);
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}
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return 0;
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}
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#else
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static int save_highmem(void) { return 0; }
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int restore_highmem(void) { return 0; }
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#endif /* CONFIG_HIGHMEM */
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static int pfn_is_nosave(unsigned long pfn)
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{
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unsigned long nosave_begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
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unsigned long nosave_end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT;
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return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
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}
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/**
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* saveable - Determine whether a page should be cloned or not.
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* @pfn: The page
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*
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* We save a page if it's Reserved, and not in the range of pages
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* statically defined as 'unsaveable', or if it isn't reserved, and
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* isn't part of a free chunk of pages.
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*/
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static int saveable(struct zone *zone, unsigned long *zone_pfn)
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{
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unsigned long pfn = *zone_pfn + zone->zone_start_pfn;
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struct page *page;
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if (!pfn_valid(pfn))
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return 0;
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page = pfn_to_page(pfn);
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BUG_ON(PageReserved(page) && PageNosave(page));
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if (PageNosave(page))
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return 0;
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if (PageReserved(page) && pfn_is_nosave(pfn)) {
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pr_debug("[nosave pfn 0x%lx]", pfn);
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return 0;
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}
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if (PageNosaveFree(page))
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return 0;
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return 1;
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}
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static unsigned count_data_pages(void)
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{
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struct zone *zone;
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unsigned long zone_pfn;
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unsigned int n = 0;
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for_each_zone (zone) {
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if (is_highmem(zone))
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continue;
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mark_free_pages(zone);
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for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
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n += saveable(zone, &zone_pfn);
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}
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return n;
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}
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static void copy_data_pages(struct pbe *pblist)
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{
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struct zone *zone;
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unsigned long zone_pfn;
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struct pbe *pbe, *p;
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pbe = pblist;
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for_each_zone (zone) {
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if (is_highmem(zone))
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continue;
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mark_free_pages(zone);
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/* This is necessary for swsusp_free() */
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for_each_pb_page (p, pblist)
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SetPageNosaveFree(virt_to_page(p));
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for_each_pbe (p, pblist)
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SetPageNosaveFree(virt_to_page(p->address));
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for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
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if (saveable(zone, &zone_pfn)) {
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struct page *page;
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page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
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BUG_ON(!pbe);
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pbe->orig_address = (unsigned long)page_address(page);
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/* copy_page is not usable for copying task structs. */
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memcpy((void *)pbe->address, (void *)pbe->orig_address, PAGE_SIZE);
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pbe = pbe->next;
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}
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}
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}
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BUG_ON(pbe);
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}
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/**
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* free_pagedir - free pages allocated with alloc_pagedir()
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*/
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static void free_pagedir(struct pbe *pblist)
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{
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struct pbe *pbe;
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while (pblist) {
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pbe = (pblist + PB_PAGE_SKIP)->next;
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ClearPageNosave(virt_to_page(pblist));
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ClearPageNosaveFree(virt_to_page(pblist));
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free_page((unsigned long)pblist);
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pblist = pbe;
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}
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}
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/**
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* fill_pb_page - Create a list of PBEs on a given memory page
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*/
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static inline void fill_pb_page(struct pbe *pbpage)
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{
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struct pbe *p;
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p = pbpage;
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pbpage += PB_PAGE_SKIP;
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do
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p->next = p + 1;
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while (++p < pbpage);
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}
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/**
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* create_pbe_list - Create a list of PBEs on top of a given chain
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* of memory pages allocated with alloc_pagedir()
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*/
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void create_pbe_list(struct pbe *pblist, unsigned int nr_pages)
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{
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struct pbe *pbpage, *p;
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unsigned int num = PBES_PER_PAGE;
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for_each_pb_page (pbpage, pblist) {
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if (num >= nr_pages)
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break;
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fill_pb_page(pbpage);
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num += PBES_PER_PAGE;
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}
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if (pbpage) {
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for (num -= PBES_PER_PAGE - 1, p = pbpage; num < nr_pages; p++, num++)
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p->next = p + 1;
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p->next = NULL;
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}
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pr_debug("create_pbe_list(): initialized %d PBEs\n", num);
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}
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/**
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* @safe_needed - on resume, for storing the PBE list and the image,
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* we can only use memory pages that do not conflict with the pages
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* which had been used before suspend.
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*
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* The unsafe pages are marked with the PG_nosave_free flag
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*
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* Allocated but unusable (ie eaten) memory pages should be marked
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* so that swsusp_free() can release them
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*/
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static inline void *alloc_image_page(gfp_t gfp_mask, int safe_needed)
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{
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void *res;
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if (safe_needed)
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do {
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res = (void *)get_zeroed_page(gfp_mask);
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if (res && PageNosaveFree(virt_to_page(res)))
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/* This is for swsusp_free() */
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SetPageNosave(virt_to_page(res));
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} while (res && PageNosaveFree(virt_to_page(res)));
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else
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res = (void *)get_zeroed_page(gfp_mask);
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if (res) {
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SetPageNosave(virt_to_page(res));
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SetPageNosaveFree(virt_to_page(res));
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}
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return res;
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}
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unsigned long get_safe_page(gfp_t gfp_mask)
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{
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return (unsigned long)alloc_image_page(gfp_mask, 1);
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}
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/**
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* alloc_pagedir - Allocate the page directory.
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*
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* First, determine exactly how many pages we need and
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* allocate them.
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*
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* We arrange the pages in a chain: each page is an array of PBES_PER_PAGE
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* struct pbe elements (pbes) and the last element in the page points
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* to the next page.
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*
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* On each page we set up a list of struct_pbe elements.
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*/
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struct pbe *alloc_pagedir(unsigned int nr_pages, gfp_t gfp_mask, int safe_needed)
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{
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unsigned int num;
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struct pbe *pblist, *pbe;
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if (!nr_pages)
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return NULL;
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pr_debug("alloc_pagedir(): nr_pages = %d\n", nr_pages);
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pblist = alloc_image_page(gfp_mask, safe_needed);
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/* FIXME: rewrite this ugly loop */
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for (pbe = pblist, num = PBES_PER_PAGE; pbe && num < nr_pages;
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pbe = pbe->next, num += PBES_PER_PAGE) {
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pbe += PB_PAGE_SKIP;
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pbe->next = alloc_image_page(gfp_mask, safe_needed);
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}
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if (!pbe) { /* get_zeroed_page() failed */
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free_pagedir(pblist);
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pblist = NULL;
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}
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return pblist;
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}
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/**
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* Free pages we allocated for suspend. Suspend pages are alocated
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* before atomic copy, so we need to free them after resume.
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*/
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void swsusp_free(void)
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{
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struct zone *zone;
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unsigned long zone_pfn;
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for_each_zone(zone) {
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for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
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if (pfn_valid(zone_pfn + zone->zone_start_pfn)) {
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struct page *page;
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page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
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if (PageNosave(page) && PageNosaveFree(page)) {
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ClearPageNosave(page);
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ClearPageNosaveFree(page);
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free_page((long) page_address(page));
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}
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}
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}
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}
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/**
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* enough_free_mem - Make sure we enough free memory to snapshot.
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*
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* Returns TRUE or FALSE after checking the number of available
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* free pages.
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*/
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static int enough_free_mem(unsigned int nr_pages)
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{
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pr_debug("swsusp: available memory: %u pages\n", nr_free_pages());
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return nr_free_pages() > (nr_pages + PAGES_FOR_IO +
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(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
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}
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int alloc_data_pages(struct pbe *pblist, gfp_t gfp_mask, int safe_needed)
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{
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struct pbe *p;
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for_each_pbe (p, pblist) {
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p->address = (unsigned long)alloc_image_page(gfp_mask, safe_needed);
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if (!p->address)
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return -ENOMEM;
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}
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return 0;
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}
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static struct pbe *swsusp_alloc(unsigned int nr_pages)
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{
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struct pbe *pblist;
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if (!(pblist = alloc_pagedir(nr_pages, GFP_ATOMIC | __GFP_COLD, 0))) {
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printk(KERN_ERR "suspend: Allocating pagedir failed.\n");
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return NULL;
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}
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create_pbe_list(pblist, nr_pages);
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if (alloc_data_pages(pblist, GFP_ATOMIC | __GFP_COLD, 0)) {
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printk(KERN_ERR "suspend: Allocating image pages failed.\n");
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swsusp_free();
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return NULL;
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}
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return pblist;
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}
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asmlinkage int swsusp_save(void)
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{
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unsigned int nr_pages;
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pr_debug("swsusp: critical section: \n");
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if (save_highmem()) {
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printk(KERN_CRIT "swsusp: Not enough free pages for highmem\n");
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restore_highmem();
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return -ENOMEM;
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}
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drain_local_pages();
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nr_pages = count_data_pages();
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printk("swsusp: Need to copy %u pages\n", nr_pages);
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pr_debug("swsusp: pages needed: %u + %lu + %u, free: %u\n",
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nr_pages,
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(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE,
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PAGES_FOR_IO, nr_free_pages());
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/* This is needed because of the fixed size of swsusp_info */
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if (MAX_PBES < (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE)
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return -ENOSPC;
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if (!enough_free_mem(nr_pages)) {
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printk(KERN_ERR "swsusp: Not enough free memory\n");
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return -ENOMEM;
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}
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if (!enough_swap(nr_pages)) {
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printk(KERN_ERR "swsusp: Not enough free swap\n");
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return -ENOSPC;
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}
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pagedir_nosave = swsusp_alloc(nr_pages);
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if (!pagedir_nosave)
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return -ENOMEM;
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/* During allocating of suspend pagedir, new cold pages may appear.
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* Kill them.
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*/
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drain_local_pages();
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copy_data_pages(pagedir_nosave);
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/*
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* End of critical section. From now on, we can write to memory,
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* but we should not touch disk. This specially means we must _not_
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* touch swap space! Except we must write out our image of course.
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*/
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nr_copy_pages = nr_pages;
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printk("swsusp: critical section/: done (%d pages copied)\n", nr_pages);
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return 0;
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}
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