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/init.h>
  14
  15#define ESSA_SET_STABLE         1
  16#define ESSA_SET_UNUSED         2
  17
  18static int cmma_flag = 1;
  19
  20static int __init cmma(char *str)
  21{
  22        char *parm;
  23
  24        parm = strstrip(str);
  25        if (strcmp(parm, "yes") == 0 || strcmp(parm, "on") == 0) {
  26                cmma_flag = 1;
  27                return 1;
  28        }
  29        cmma_flag = 0;
  30        if (strcmp(parm, "no") == 0 || strcmp(parm, "off") == 0)
  31                return 1;
  32        return 0;
  33}
  34__setup("cmma=", cmma);
  35
  36void __init cmma_init(void)
  37{
  38        register unsigned long tmp asm("0") = 0;
  39        register int rc asm("1") = -EOPNOTSUPP;
  40
  41        if (!cmma_flag)
  42                return;
  43        asm volatile(
  44                "       .insn rrf,0xb9ab0000,%1,%1,0,0\n"
  45                "0:     la      %0,0\n"
  46                "1:\n"
  47                EX_TABLE(0b,1b)
  48                : "+&d" (rc), "+&d" (tmp));
  49        if (rc)
  50                cmma_flag = 0;
  51}
  52
  53static inline void set_page_unstable(struct page *page, int order)
  54{
  55        int i, rc;
  56
  57        for (i = 0; i < (1 << order); i++)
  58                asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
  59                             : "=&d" (rc)
  60                             : "a" (page_to_phys(page + i)),
  61                               "i" (ESSA_SET_UNUSED));
  62}
  63
  64void arch_free_page(struct page *page, int order)
  65{
  66        if (!cmma_flag)
  67                return;
  68        set_page_unstable(page, order);
  69}
  70
  71static inline void set_page_stable(struct page *page, int order)
  72{
  73        int i, rc;
  74
  75        for (i = 0; i < (1 << order); i++)
  76                asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
  77                             : "=&d" (rc)
  78                             : "a" (page_to_phys(page + i)),
  79                               "i" (ESSA_SET_STABLE));
  80}
  81
  82void arch_alloc_page(struct page *page, int order)
  83{
  84        if (!cmma_flag)
  85                return;
  86        set_page_stable(page, order);
  87}
  88
  89void arch_set_page_states(int make_stable)
  90{
  91        unsigned long flags, order, t;
  92        struct list_head *l;
  93        struct page *page;
  94        struct zone *zone;
  95
  96        if (!cmma_flag)
  97                return;
  98        if (make_stable)
  99                drain_local_pages(NULL);
 100        for_each_populated_zone(zone) {
 101                spin_lock_irqsave(&zone->lock, flags);
 102                for_each_migratetype_order(order, t) {
 103                        list_for_each(l, &zone->free_area[order].free_list[t]) {
 104                                page = list_entry(l, struct page, lru);
 105                                if (make_stable)
 106                                        set_page_stable(page, order);
 107                                else
 108                                        set_page_unstable(page, order);
 109                        }
 110                }
 111                spin_unlock_irqrestore(&zone->lock, flags);
 112        }
 113}
 114