846955c8af
On resume the system that loads the to be resumed image might have unstable pages. When the resume image is copied back and a write access happen to an unstable page this causes an exception and the system crashes. To fix this set all free pages to stable before copying the resumed image data. Also after everything has been restored set all free pages of the resumed system to unstable again. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
114 lines
2.2 KiB
C
114 lines
2.2 KiB
C
/*
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* Copyright IBM Corp. 2008
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*
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* Guest page hinting for unused pages.
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*
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* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
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*/
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/types.h>
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#include <linux/mm.h>
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#include <linux/init.h>
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#define ESSA_SET_STABLE 1
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#define ESSA_SET_UNUSED 2
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static int cmma_flag = 1;
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static int __init cmma(char *str)
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{
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char *parm;
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parm = strstrip(str);
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if (strcmp(parm, "yes") == 0 || strcmp(parm, "on") == 0) {
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cmma_flag = 1;
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return 1;
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}
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cmma_flag = 0;
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if (strcmp(parm, "no") == 0 || strcmp(parm, "off") == 0)
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return 1;
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return 0;
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}
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__setup("cmma=", cmma);
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void __init cmma_init(void)
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{
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register unsigned long tmp asm("0") = 0;
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register int rc asm("1") = -EOPNOTSUPP;
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if (!cmma_flag)
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return;
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asm volatile(
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" .insn rrf,0xb9ab0000,%1,%1,0,0\n"
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"0: la %0,0\n"
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"1:\n"
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EX_TABLE(0b,1b)
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: "+&d" (rc), "+&d" (tmp));
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if (rc)
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cmma_flag = 0;
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}
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static inline void set_page_unstable(struct page *page, int order)
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{
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int i, rc;
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for (i = 0; i < (1 << order); i++)
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asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
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: "=&d" (rc)
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: "a" (page_to_phys(page + i)),
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"i" (ESSA_SET_UNUSED));
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}
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void arch_free_page(struct page *page, int order)
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{
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if (!cmma_flag)
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return;
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set_page_unstable(page, order);
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}
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static inline void set_page_stable(struct page *page, int order)
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{
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int i, rc;
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for (i = 0; i < (1 << order); i++)
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asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
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: "=&d" (rc)
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: "a" (page_to_phys(page + i)),
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"i" (ESSA_SET_STABLE));
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}
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void arch_alloc_page(struct page *page, int order)
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{
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if (!cmma_flag)
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return;
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set_page_stable(page, order);
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}
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void arch_set_page_states(int make_stable)
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{
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unsigned long flags, order, t;
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struct list_head *l;
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struct page *page;
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struct zone *zone;
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if (!cmma_flag)
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return;
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if (make_stable)
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drain_local_pages(NULL);
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for_each_populated_zone(zone) {
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spin_lock_irqsave(&zone->lock, flags);
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for_each_migratetype_order(order, t) {
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list_for_each(l, &zone->free_area[order].free_list[t]) {
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page = list_entry(l, struct page, lru);
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if (make_stable)
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set_page_stable(page, order);
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else
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set_page_unstable(page, order);
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}
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}
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spin_unlock_irqrestore(&zone->lock, flags);
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}
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}
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