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 21 static int cmma_flag = 1; 22 23 static 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 39 void __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 64 static 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 75 void arch_free_page(struct page *page, int order) 76 { 77 if (!cmma_flag) 78 return; 79 set_page_unstable(page, order); 80 } 81 82 static 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 93 void arch_alloc_page(struct page *page, int order) 94 { 95 if (!cmma_flag) 96 return; 97 set_page_stable(page, order); 98 } 99 100 void 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