1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2019 SiFive 4 */ 5 6 #include <linux/pagewalk.h> 7 #include <linux/pgtable.h> 8 #include <asm/tlbflush.h> 9 #include <asm/bitops.h> 10 #include <asm/set_memory.h> 11 12 struct pageattr_masks { 13 pgprot_t set_mask; 14 pgprot_t clear_mask; 15 }; 16 17 static unsigned long set_pageattr_masks(unsigned long val, struct mm_walk *walk) 18 { 19 struct pageattr_masks *masks = walk->private; 20 unsigned long new_val = val; 21 22 new_val &= ~(pgprot_val(masks->clear_mask)); 23 new_val |= (pgprot_val(masks->set_mask)); 24 25 return new_val; 26 } 27 28 static int pageattr_pgd_entry(pgd_t *pgd, unsigned long addr, 29 unsigned long next, struct mm_walk *walk) 30 { 31 pgd_t val = READ_ONCE(*pgd); 32 33 if (pgd_leaf(val)) { 34 val = __pgd(set_pageattr_masks(pgd_val(val), walk)); 35 set_pgd(pgd, val); 36 } 37 38 return 0; 39 } 40 41 static int pageattr_p4d_entry(p4d_t *p4d, unsigned long addr, 42 unsigned long next, struct mm_walk *walk) 43 { 44 p4d_t val = READ_ONCE(*p4d); 45 46 if (p4d_leaf(val)) { 47 val = __p4d(set_pageattr_masks(p4d_val(val), walk)); 48 set_p4d(p4d, val); 49 } 50 51 return 0; 52 } 53 54 static int pageattr_pud_entry(pud_t *pud, unsigned long addr, 55 unsigned long next, struct mm_walk *walk) 56 { 57 pud_t val = READ_ONCE(*pud); 58 59 if (pud_leaf(val)) { 60 val = __pud(set_pageattr_masks(pud_val(val), walk)); 61 set_pud(pud, val); 62 } 63 64 return 0; 65 } 66 67 static int pageattr_pmd_entry(pmd_t *pmd, unsigned long addr, 68 unsigned long next, struct mm_walk *walk) 69 { 70 pmd_t val = READ_ONCE(*pmd); 71 72 if (pmd_leaf(val)) { 73 val = __pmd(set_pageattr_masks(pmd_val(val), walk)); 74 set_pmd(pmd, val); 75 } 76 77 return 0; 78 } 79 80 static int pageattr_pte_entry(pte_t *pte, unsigned long addr, 81 unsigned long next, struct mm_walk *walk) 82 { 83 pte_t val = READ_ONCE(*pte); 84 85 val = __pte(set_pageattr_masks(pte_val(val), walk)); 86 set_pte(pte, val); 87 88 return 0; 89 } 90 91 static int pageattr_pte_hole(unsigned long addr, unsigned long next, 92 int depth, struct mm_walk *walk) 93 { 94 /* Nothing to do here */ 95 return 0; 96 } 97 98 static const struct mm_walk_ops pageattr_ops = { 99 .pgd_entry = pageattr_pgd_entry, 100 .p4d_entry = pageattr_p4d_entry, 101 .pud_entry = pageattr_pud_entry, 102 .pmd_entry = pageattr_pmd_entry, 103 .pte_entry = pageattr_pte_entry, 104 .pte_hole = pageattr_pte_hole, 105 }; 106 107 static int __set_memory(unsigned long addr, int numpages, pgprot_t set_mask, 108 pgprot_t clear_mask) 109 { 110 int ret; 111 unsigned long start = addr; 112 unsigned long end = start + PAGE_SIZE * numpages; 113 struct pageattr_masks masks = { 114 .set_mask = set_mask, 115 .clear_mask = clear_mask 116 }; 117 118 if (!numpages) 119 return 0; 120 121 mmap_write_lock(&init_mm); 122 ret = walk_page_range_novma(&init_mm, start, end, &pageattr_ops, NULL, 123 &masks); 124 mmap_write_unlock(&init_mm); 125 126 flush_tlb_kernel_range(start, end); 127 128 return ret; 129 } 130 131 int set_memory_rw_nx(unsigned long addr, int numpages) 132 { 133 return __set_memory(addr, numpages, __pgprot(_PAGE_READ | _PAGE_WRITE), 134 __pgprot(_PAGE_EXEC)); 135 } 136 137 int set_memory_ro(unsigned long addr, int numpages) 138 { 139 return __set_memory(addr, numpages, __pgprot(_PAGE_READ), 140 __pgprot(_PAGE_WRITE)); 141 } 142 143 int set_memory_rw(unsigned long addr, int numpages) 144 { 145 return __set_memory(addr, numpages, __pgprot(_PAGE_READ | _PAGE_WRITE), 146 __pgprot(0)); 147 } 148 149 int set_memory_x(unsigned long addr, int numpages) 150 { 151 return __set_memory(addr, numpages, __pgprot(_PAGE_EXEC), __pgprot(0)); 152 } 153 154 int set_memory_nx(unsigned long addr, int numpages) 155 { 156 return __set_memory(addr, numpages, __pgprot(0), __pgprot(_PAGE_EXEC)); 157 } 158 159 int set_direct_map_invalid_noflush(struct page *page) 160 { 161 int ret; 162 unsigned long start = (unsigned long)page_address(page); 163 unsigned long end = start + PAGE_SIZE; 164 struct pageattr_masks masks = { 165 .set_mask = __pgprot(0), 166 .clear_mask = __pgprot(_PAGE_PRESENT) 167 }; 168 169 mmap_read_lock(&init_mm); 170 ret = walk_page_range(&init_mm, start, end, &pageattr_ops, &masks); 171 mmap_read_unlock(&init_mm); 172 173 return ret; 174 } 175 176 int set_direct_map_default_noflush(struct page *page) 177 { 178 int ret; 179 unsigned long start = (unsigned long)page_address(page); 180 unsigned long end = start + PAGE_SIZE; 181 struct pageattr_masks masks = { 182 .set_mask = PAGE_KERNEL, 183 .clear_mask = __pgprot(0) 184 }; 185 186 mmap_read_lock(&init_mm); 187 ret = walk_page_range(&init_mm, start, end, &pageattr_ops, &masks); 188 mmap_read_unlock(&init_mm); 189 190 return ret; 191 } 192 193 #ifdef CONFIG_DEBUG_PAGEALLOC 194 void __kernel_map_pages(struct page *page, int numpages, int enable) 195 { 196 if (!debug_pagealloc_enabled()) 197 return; 198 199 if (enable) 200 __set_memory((unsigned long)page_address(page), numpages, 201 __pgprot(_PAGE_PRESENT), __pgprot(0)); 202 else 203 __set_memory((unsigned long)page_address(page), numpages, 204 __pgprot(0), __pgprot(_PAGE_PRESENT)); 205 } 206 #endif 207 208 bool kernel_page_present(struct page *page) 209 { 210 unsigned long addr = (unsigned long)page_address(page); 211 pgd_t *pgd; 212 pud_t *pud; 213 p4d_t *p4d; 214 pmd_t *pmd; 215 pte_t *pte; 216 217 pgd = pgd_offset_k(addr); 218 if (!pgd_present(*pgd)) 219 return false; 220 221 p4d = p4d_offset(pgd, addr); 222 if (!p4d_present(*p4d)) 223 return false; 224 225 pud = pud_offset(p4d, addr); 226 if (!pud_present(*pud)) 227 return false; 228 229 pmd = pmd_offset(pud, addr); 230 if (!pmd_present(*pmd)) 231 return false; 232 233 pte = pte_offset_kernel(pmd, addr); 234 return pte_present(*pte); 235 } 236