LXR linux/arch/s390/mm/page-states.c

   1/*
   2 * Copyright IBM Corp. 2008
   3 *
   4 * Guest page hinting for unused pages.
   5 *
   6 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
   7 */
   8
   9#include <linux/kernel.h>
  10#include <linux/errno.h>
  11#include <linux/types.h>
  12#include <linux/mm.h>
  13#include <linux/gfp.h>
  14#include <linux/init.h>
  15#include <asm/setup.h>
  16#include <asm/ipl.h>
  17
  18#define ESSA_SET_STABLE         1
  19#define ESSA_SET_UNUSED         2
  20
  21static int cmma_flag = 1;
  22
  23static int __init cmma(char *str)
  24{
  25        char *parm;
  26
  27        parm = strstrip(str);
  28        if (strcmp(parm, "yes") == 0 || strcmp(parm, "on") == 0) {
  29                cmma_flag = 1;
  30                return 1;
  31        }
  32        cmma_flag = 0;
  33        if (strcmp(parm, "no") == 0 || strcmp(parm, "off") == 0)
  34                return 1;
  35        return 0;
  36}
  37__setup("cmma=", cmma);
  38
  39void __init cmma_init(void)
  40{
  41        register unsigned long tmp asm("0") = 0;
  42        register int rc asm("1") = -EOPNOTSUPP;
  43
  44        if (!cmma_flag)
  45                return;
  46        /*
  47         * Disable CMM for dump, otherwise  the tprot based memory
  48         * detection can fail because of unstable pages.
  49         */
  50        if (OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP) {
  51                cmma_flag = 0;
  52                return;
  53        }
  54        asm volatile(
  55                "       .insn rrf,0xb9ab0000,%1,%1,0,0\n"
  56                "0:     la      %0,0\n"
  57                "1:\n"
  58                EX_TABLE(0b,1b)
  59                : "+&d" (rc), "+&d" (tmp));
  60        if (rc)
  61                cmma_flag = 0;
  62}
  63
  64static inline void set_page_unstable(struct page *page, int order)
  65{
  66        int i, rc;
  67
  68        for (i = 0; i < (1 << order); i++)
  69                asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
  70                             : "=&d" (rc)
  71                             : "a" (page_to_phys(page + i)),
  72                               "i" (ESSA_SET_UNUSED));
  73}
  74
  75void arch_free_page(struct page *page, int order)
  76{
  77        if (!cmma_flag)
  78                return;
  79        set_page_unstable(page, order);
  80}
  81
  82static inline void set_page_stable(struct page *page, int order)
  83{
  84        int i, rc;
  85
  86        for (i = 0; i < (1 << order); i++)
  87                asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
  88                             : "=&d" (rc)
  89                             : "a" (page_to_phys(page + i)),
  90                               "i" (ESSA_SET_STABLE));
  91}
  92
  93void arch_alloc_page(struct page *page, int order)
  94{
  95        if (!cmma_flag)
  96                return;
  97        set_page_stable(page, order);
  98}
  99
 100void arch_set_page_states(int make_stable)
 101{
 102        unsigned long flags, order, t;
 103        struct list_head *l;
 104        struct page *page;
 105        struct zone *zone;
 106
 107        if (!cmma_flag)
 108                return;
 109        if (make_stable)
 110                drain_local_pages(NULL);
 111        for_each_populated_zone(zone) {
 112                spin_lock_irqsave(&zone->lock, flags);
 113                for_each_migratetype_order(order, t) {
 114                        list_for_each(l, &zone->free_area[order].free_list[t]) {
 115                                page = list_entry(l, struct page, lru);
 116                                if (make_stable)
 117                                        set_page_stable(page, order);
 118                                else
 119                                        set_page_unstable(page, order);
 120                        }
 121                }
 122                spin_unlock_irqrestore(&zone->lock, flags);
 123        }
 124}
 125