forked from luck/tmp_suning_uos_patched
d7736ff5be
Dumps created by kdump or zfcpdump can contain invalid memory holes when dumping z/VM systems that have memory pressure. For example: # zgetdump -i /proc/vmcore. Memory map: 0000000000000000 - 0000000000bfffff (12 MB) 0000000000e00000 - 00000000014fffff (7 MB) 000000000bd00000 - 00000000f3bfffff (3711 MB) The memory detection function find_memory_chunks() issues tprot to find valid memory chunks. In case of CMM it can happen that pages are marked as unstable via set_page_unstable() in arch_free_page(). If z/VM has released that pages, tprot returns -EFAULT and indicates a memory hole. So fix this and switch off CMM in case of kdump or zfcpdump. Cc: <stable@vger.kernel.org> Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
125 lines
2.5 KiB
C
125 lines
2.5 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/gfp.h>
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#include <linux/init.h>
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#include <asm/setup.h>
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#include <asm/ipl.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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/*
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* Disable CMM for dump, otherwise the tprot based memory
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* detection can fail because of unstable pages.
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*/
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if (OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP) {
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cmma_flag = 0;
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return;
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}
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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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