1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright IBM Corp. 2008 4 * 5 * Guest page hinting for unused pages. 6 * 7 * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com> 8 */ 9 10 #include <linux/kernel.h> 11 #include <linux/errno.h> 12 #include <linux/types.h> 13 #include <linux/mm.h> 14 #include <linux/memblock.h> 15 #include <linux/gfp.h> 16 #include <linux/init.h> 17 #include <asm/facility.h> 18 #include <asm/page-states.h> 19 20 static int cmma_flag = 1; 21 22 static int __init cmma(char *str) 23 { 24 bool enabled; 25 26 if (!kstrtobool(str, &enabled)) 27 cmma_flag = enabled; 28 return 1; 29 } 30 __setup("cmma=", cmma); 31 32 static inline int cmma_test_essa(void) 33 { 34 unsigned long tmp = 0; 35 int rc = -EOPNOTSUPP; 36 37 /* test ESSA_GET_STATE */ 38 asm volatile( 39 " .insn rrf,0xb9ab0000,%[tmp],%[tmp],%[cmd],0\n" 40 "0: la %[rc],0\n" 41 "1:\n" 42 EX_TABLE(0b,1b) 43 : [rc] "+&d" (rc), [tmp] "+&d" (tmp) 44 : [cmd] "i" (ESSA_GET_STATE)); 45 return rc; 46 } 47 48 void __init cmma_init(void) 49 { 50 if (!cmma_flag) 51 return; 52 if (cmma_test_essa()) { 53 cmma_flag = 0; 54 return; 55 } 56 if (test_facility(147)) 57 cmma_flag = 2; 58 } 59 60 static inline unsigned char get_page_state(struct page *page) 61 { 62 unsigned char state; 63 64 asm volatile(" .insn rrf,0xb9ab0000,%0,%1,%2,0" 65 : "=&d" (state) 66 : "a" (page_to_phys(page)), 67 "i" (ESSA_GET_STATE)); 68 return state & 0x3f; 69 } 70 71 static inline void set_page_unused(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_UNUSED)); 80 } 81 82 static inline void set_page_stable_dat(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 static inline void set_page_stable_nodat(struct page *page, int order) 94 { 95 int i, rc; 96 97 for (i = 0; i < (1 << order); i++) 98 asm volatile(".insn rrf,0xb9ab0000,%0,%1,%2,0" 99 : "=&d" (rc) 100 : "a" (page_to_phys(page + i)), 101 "i" (ESSA_SET_STABLE_NODAT)); 102 } 103 104 static void mark_kernel_pmd(pud_t *pud, unsigned long addr, unsigned long end) 105 { 106 unsigned long next; 107 struct page *page; 108 pmd_t *pmd; 109 110 pmd = pmd_offset(pud, addr); 111 do { 112 next = pmd_addr_end(addr, end); 113 if (pmd_none(*pmd) || pmd_large(*pmd)) 114 continue; 115 page = phys_to_page(pmd_val(*pmd)); 116 set_bit(PG_arch_1, &page->flags); 117 } while (pmd++, addr = next, addr != end); 118 } 119 120 static void mark_kernel_pud(p4d_t *p4d, unsigned long addr, unsigned long end) 121 { 122 unsigned long next; 123 struct page *page; 124 pud_t *pud; 125 int i; 126 127 pud = pud_offset(p4d, addr); 128 do { 129 next = pud_addr_end(addr, end); 130 if (pud_none(*pud) || pud_large(*pud)) 131 continue; 132 if (!pud_folded(*pud)) { 133 page = phys_to_page(pud_val(*pud)); 134 for (i = 0; i < 3; i++) 135 set_bit(PG_arch_1, &page[i].flags); 136 } 137 mark_kernel_pmd(pud, addr, next); 138 } while (pud++, addr = next, addr != end); 139 } 140 141 static void mark_kernel_p4d(pgd_t *pgd, unsigned long addr, unsigned long end) 142 { 143 unsigned long next; 144 struct page *page; 145 p4d_t *p4d; 146 int i; 147 148 p4d = p4d_offset(pgd, addr); 149 do { 150 next = p4d_addr_end(addr, end); 151 if (p4d_none(*p4d)) 152 continue; 153 if (!p4d_folded(*p4d)) { 154 page = phys_to_page(p4d_val(*p4d)); 155 for (i = 0; i < 3; i++) 156 set_bit(PG_arch_1, &page[i].flags); 157 } 158 mark_kernel_pud(p4d, addr, next); 159 } while (p4d++, addr = next, addr != end); 160 } 161 162 static void mark_kernel_pgd(void) 163 { 164 unsigned long addr, next; 165 struct page *page; 166 pgd_t *pgd; 167 int i; 168 169 addr = 0; 170 pgd = pgd_offset_k(addr); 171 do { 172 next = pgd_addr_end(addr, MODULES_END); 173 if (pgd_none(*pgd)) 174 continue; 175 if (!pgd_folded(*pgd)) { 176 page = phys_to_page(pgd_val(*pgd)); 177 for (i = 0; i < 3; i++) 178 set_bit(PG_arch_1, &page[i].flags); 179 } 180 mark_kernel_p4d(pgd, addr, next); 181 } while (pgd++, addr = next, addr != MODULES_END); 182 } 183 184 void __init cmma_init_nodat(void) 185 { 186 struct page *page; 187 unsigned long start, end, ix; 188 int i; 189 190 if (cmma_flag < 2) 191 return; 192 /* Mark pages used in kernel page tables */ 193 mark_kernel_pgd(); 194 195 /* Set all kernel pages not used for page tables to stable/no-dat */ 196 for_each_mem_pfn_range(i, MAX_NUMNODES, &start, &end, NULL) { 197 page = pfn_to_page(start); 198 for (ix = start; ix < end; ix++, page++) { 199 if (__test_and_clear_bit(PG_arch_1, &page->flags)) 200 continue; /* skip page table pages */ 201 if (!list_empty(&page->lru)) 202 continue; /* skip free pages */ 203 set_page_stable_nodat(page, 0); 204 } 205 } 206 } 207 208 void arch_free_page(struct page *page, int order) 209 { 210 if (!cmma_flag) 211 return; 212 set_page_unused(page, order); 213 } 214 215 void arch_alloc_page(struct page *page, int order) 216 { 217 if (!cmma_flag) 218 return; 219 if (cmma_flag < 2) 220 set_page_stable_dat(page, order); 221 else 222 set_page_stable_nodat(page, order); 223 } 224 225 void arch_set_page_dat(struct page *page, int order) 226 { 227 if (!cmma_flag) 228 return; 229 set_page_stable_dat(page, order); 230 } 231