1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) 4 */ 5 6 #include <linux/mm.h> 7 #include <linux/module.h> 8 #include <linux/sched/signal.h> 9 10 #include <asm/tlbflush.h> 11 #include <asm/mmu_context.h> 12 #include <as-layout.h> 13 #include <mem_user.h> 14 #include <os.h> 15 #include <skas.h> 16 #include <kern_util.h> 17 18 struct vm_ops { 19 struct mm_id *mm_idp; 20 21 int (*mmap)(struct mm_id *mm_idp, 22 unsigned long virt, unsigned long len, int prot, 23 int phys_fd, unsigned long long offset); 24 int (*unmap)(struct mm_id *mm_idp, 25 unsigned long virt, unsigned long len); 26 }; 27 28 static int kern_map(struct mm_id *mm_idp, 29 unsigned long virt, unsigned long len, int prot, 30 int phys_fd, unsigned long long offset) 31 { 32 /* TODO: Why is executable needed to be always set in the kernel? */ 33 return os_map_memory((void *)virt, phys_fd, offset, len, 34 prot & UM_PROT_READ, prot & UM_PROT_WRITE, 35 1); 36 } 37 38 static int kern_unmap(struct mm_id *mm_idp, 39 unsigned long virt, unsigned long len) 40 { 41 return os_unmap_memory((void *)virt, len); 42 } 43 44 void report_enomem(void) 45 { 46 printk(KERN_ERR "UML ran out of memory on the host side! " 47 "This can happen due to a memory limitation or " 48 "vm.max_map_count has been reached.\n"); 49 } 50 51 static inline int update_pte_range(pmd_t *pmd, unsigned long addr, 52 unsigned long end, 53 struct vm_ops *ops) 54 { 55 pte_t *pte; 56 int ret = 0; 57 58 pte = pte_offset_kernel(pmd, addr); 59 do { 60 if (!pte_needsync(*pte)) 61 continue; 62 63 if (pte_present(*pte)) { 64 __u64 offset; 65 unsigned long phys = pte_val(*pte) & PAGE_MASK; 66 int fd = phys_mapping(phys, &offset); 67 int r, w, x, prot; 68 69 r = pte_read(*pte); 70 w = pte_write(*pte); 71 x = pte_exec(*pte); 72 if (!pte_young(*pte)) { 73 r = 0; 74 w = 0; 75 } else if (!pte_dirty(*pte)) 76 w = 0; 77 78 prot = (r ? UM_PROT_READ : 0) | 79 (w ? UM_PROT_WRITE : 0) | 80 (x ? UM_PROT_EXEC : 0); 81 82 ret = ops->mmap(ops->mm_idp, addr, PAGE_SIZE, 83 prot, fd, offset); 84 } else 85 ret = ops->unmap(ops->mm_idp, addr, PAGE_SIZE); 86 87 *pte = pte_mkuptodate(*pte); 88 } while (pte++, addr += PAGE_SIZE, ((addr < end) && !ret)); 89 return ret; 90 } 91 92 static inline int update_pmd_range(pud_t *pud, unsigned long addr, 93 unsigned long end, 94 struct vm_ops *ops) 95 { 96 pmd_t *pmd; 97 unsigned long next; 98 int ret = 0; 99 100 pmd = pmd_offset(pud, addr); 101 do { 102 next = pmd_addr_end(addr, end); 103 if (!pmd_present(*pmd)) { 104 if (pmd_needsync(*pmd)) { 105 ret = ops->unmap(ops->mm_idp, addr, 106 next - addr); 107 pmd_mkuptodate(*pmd); 108 } 109 } 110 else ret = update_pte_range(pmd, addr, next, ops); 111 } while (pmd++, addr = next, ((addr < end) && !ret)); 112 return ret; 113 } 114 115 static inline int update_pud_range(p4d_t *p4d, unsigned long addr, 116 unsigned long end, 117 struct vm_ops *ops) 118 { 119 pud_t *pud; 120 unsigned long next; 121 int ret = 0; 122 123 pud = pud_offset(p4d, addr); 124 do { 125 next = pud_addr_end(addr, end); 126 if (!pud_present(*pud)) { 127 if (pud_needsync(*pud)) { 128 ret = ops->unmap(ops->mm_idp, addr, 129 next - addr); 130 pud_mkuptodate(*pud); 131 } 132 } 133 else ret = update_pmd_range(pud, addr, next, ops); 134 } while (pud++, addr = next, ((addr < end) && !ret)); 135 return ret; 136 } 137 138 static inline int update_p4d_range(pgd_t *pgd, unsigned long addr, 139 unsigned long end, 140 struct vm_ops *ops) 141 { 142 p4d_t *p4d; 143 unsigned long next; 144 int ret = 0; 145 146 p4d = p4d_offset(pgd, addr); 147 do { 148 next = p4d_addr_end(addr, end); 149 if (!p4d_present(*p4d)) { 150 if (p4d_needsync(*p4d)) { 151 ret = ops->unmap(ops->mm_idp, addr, 152 next - addr); 153 p4d_mkuptodate(*p4d); 154 } 155 } else 156 ret = update_pud_range(p4d, addr, next, ops); 157 } while (p4d++, addr = next, ((addr < end) && !ret)); 158 return ret; 159 } 160 161 int um_tlb_sync(struct mm_struct *mm) 162 { 163 pgd_t *pgd; 164 struct vm_ops ops; 165 unsigned long addr = mm->context.sync_tlb_range_from, next; 166 int ret = 0; 167 168 if (mm->context.sync_tlb_range_to == 0) 169 return 0; 170 171 ops.mm_idp = &mm->context.id; 172 if (mm == &init_mm) { 173 ops.mmap = kern_map; 174 ops.unmap = kern_unmap; 175 } else { 176 ops.mmap = map; 177 ops.unmap = unmap; 178 } 179 180 pgd = pgd_offset(mm, addr); 181 do { 182 next = pgd_addr_end(addr, mm->context.sync_tlb_range_to); 183 if (!pgd_present(*pgd)) { 184 if (pgd_needsync(*pgd)) { 185 ret = ops.unmap(ops.mm_idp, addr, 186 next - addr); 187 pgd_mkuptodate(*pgd); 188 } 189 } else 190 ret = update_p4d_range(pgd, addr, next, &ops); 191 } while (pgd++, addr = next, 192 ((addr < mm->context.sync_tlb_range_to) && !ret)); 193 194 if (ret == -ENOMEM) 195 report_enomem(); 196 197 mm->context.sync_tlb_range_from = 0; 198 mm->context.sync_tlb_range_to = 0; 199 200 return ret; 201 } 202 203 void flush_tlb_all(void) 204 { 205 /* 206 * Don't bother flushing if this address space is about to be 207 * destroyed. 208 */ 209 if (atomic_read(¤t->mm->mm_users) == 0) 210 return; 211 212 flush_tlb_mm(current->mm); 213 } 214 215 void flush_tlb_mm(struct mm_struct *mm) 216 { 217 struct vm_area_struct *vma; 218 VMA_ITERATOR(vmi, mm, 0); 219 220 for_each_vma(vmi, vma) 221 um_tlb_mark_sync(mm, vma->vm_start, vma->vm_end); 222 } 223