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 18 static int cmma_flag = 1; 19 20 static 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 36 void __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 53 static 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 64 void arch_free_page(struct page *page, int order) 65 { 66 if (!cmma_flag) 67 return; 68 set_page_unstable(page, order); 69 } 70 71 static 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 82 void arch_alloc_page(struct page *page, int order) 83 { 84 if (!cmma_flag) 85 return; 86 set_page_stable(page, order); 87 } 88 89 void 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