2 * Copyright IBM Corp. 2008
4 * Guest page hinting for unused pages.
6 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
9 #include <linux/kernel.h>
10 #include <linux/errno.h>
11 #include <linux/types.h>
13 #include <linux/init.h>
15 #define ESSA_SET_STABLE 1
16 #define ESSA_SET_UNUSED 2
18 static int cmma_flag = 1;
20 static int __init cmma(char *str)
25 if (strcmp(parm, "yes") == 0 || strcmp(parm, "on") == 0) {
30 if (strcmp(parm, "no") == 0 || strcmp(parm, "off") == 0)
34 __setup("cmma=", cmma);
36 void __init cmma_init(void)
38 register unsigned long tmp asm("0") = 0;
39 register int rc asm("1") = -EOPNOTSUPP;
44 " .insn rrf,0xb9ab0000,%1,%1,0,0\n"
48 : "+&d" (rc), "+&d" (tmp));
53 static inline void set_page_unstable(struct page *page, int order)
57 for (i = 0; i < (1 << order); i++)
58 asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
60 : "a" (page_to_phys(page + i)),
61 "i" (ESSA_SET_UNUSED));
64 void arch_free_page(struct page *page, int order)
68 set_page_unstable(page, order);
71 static inline void set_page_stable(struct page *page, int order)
75 for (i = 0; i < (1 << order); i++)
76 asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0"
78 : "a" (page_to_phys(page + i)),
79 "i" (ESSA_SET_STABLE));
82 void arch_alloc_page(struct page *page, int order)
86 set_page_stable(page, order);
89 void arch_set_page_states(int make_stable)
91 unsigned long flags, order, t;
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);
106 set_page_stable(page, order);
108 set_page_unstable(page, order);
111 spin_unlock_irqrestore(&zone->lock, flags);