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 return os_map_memory((void *)virt, phys_fd, offset, len, 33 prot & UM_PROT_READ, prot & UM_PROT_WRITE, 34 prot & UM_PROT_EXEC); 35 } 36 37 static int kern_unmap(struct mm_id *mm_idp, 38 unsigned long virt, unsigned long len) 39 { 40 return os_unmap_memory((void *)virt, len); 41 } 42 43 void report_enomem(void) 44 { 45 printk(KERN_ERR "UML ran out of memory on the host side! " 46 "This can happen due to a memory limitation or " 47 "vm.max_map_count has been reached.\n"); 48 } 49 50 static inline int update_pte_range(pmd_t *pmd, unsigned long addr, 51 unsigned long end, 52 struct vm_ops *ops) 53 { 54 pte_t *pte; 55 int ret = 0; 56 57 pte = pte_offset_kernel(pmd, addr); 58 do { 59 if (!pte_needsync(*pte)) 60 continue; 61 62 if (pte_present(*pte)) { 63 __u64 offset; 64 unsigned long phys = pte_val(*pte) & PAGE_MASK; 65 int fd = phys_mapping(phys, &offset); 66 int r, w, x, prot; 67 68 r = pte_read(*pte); 69 w = pte_write(*pte); 70 x = pte_exec(*pte); 71 if (!pte_young(*pte)) { 72 r = 0; 73 w = 0; 74 } else if (!pte_dirty(*pte)) 75 w = 0; 76 77 prot = (r ? UM_PROT_READ : 0) | 78 (w ? UM_PROT_WRITE : 0) | 79 (x ? UM_PROT_EXEC : 0); 80 81 ret = ops->mmap(ops->mm_idp, addr, PAGE_SIZE, 82 prot, fd, offset); 83 } else 84 ret = ops->unmap(ops->mm_idp, addr, PAGE_SIZE); 85 86 *pte = pte_mkuptodate(*pte); 87 } while (pte++, addr += PAGE_SIZE, ((addr < end) && !ret)); 88 return ret; 89 } 90 91 static inline int update_pmd_range(pud_t *pud, unsigned long addr, 92 unsigned long end, 93 struct vm_ops *ops) 94 { 95 pmd_t *pmd; 96 unsigned long next; 97 int ret = 0; 98 99 pmd = pmd_offset(pud, addr); 100 do { 101 next = pmd_addr_end(addr, end); 102 if (!pmd_present(*pmd)) { 103 if (pmd_needsync(*pmd)) { 104 ret = ops->unmap(ops->mm_idp, addr, 105 next - addr); 106 pmd_mkuptodate(*pmd); 107 } 108 } 109 else ret = update_pte_range(pmd, addr, next, ops); 110 } while (pmd++, addr = next, ((addr < end) && !ret)); 111 return ret; 112 } 113 114 static inline int update_pud_range(p4d_t *p4d, unsigned long addr, 115 unsigned long end, 116 struct vm_ops *ops) 117 { 118 pud_t *pud; 119 unsigned long next; 120 int ret = 0; 121 122 pud = pud_offset(p4d, addr); 123 do { 124 next = pud_addr_end(addr, end); 125 if (!pud_present(*pud)) { 126 if (pud_needsync(*pud)) { 127 ret = ops->unmap(ops->mm_idp, addr, 128 next - addr); 129 pud_mkuptodate(*pud); 130 } 131 } 132 else ret = update_pmd_range(pud, addr, next, ops); 133 } while (pud++, addr = next, ((addr < end) && !ret)); 134 return ret; 135 } 136 137 static inline int update_p4d_range(pgd_t *pgd, unsigned long addr, 138 unsigned long end, 139 struct vm_ops *ops) 140 { 141 p4d_t *p4d; 142 unsigned long next; 143 int ret = 0; 144 145 p4d = p4d_offset(pgd, addr); 146 do { 147 next = p4d_addr_end(addr, end); 148 if (!p4d_present(*p4d)) { 149 if (p4d_needsync(*p4d)) { 150 ret = ops->unmap(ops->mm_idp, addr, 151 next - addr); 152 p4d_mkuptodate(*p4d); 153 } 154 } else 155 ret = update_pud_range(p4d, addr, next, ops); 156 } while (p4d++, addr = next, ((addr < end) && !ret)); 157 return ret; 158 } 159 160 int um_tlb_sync(struct mm_struct *mm) 161 { 162 pgd_t *pgd; 163 struct vm_ops ops; 164 unsigned long addr, next; 165 int ret = 0; 166 167 guard(spinlock_irqsave)(&mm->page_table_lock); 168 guard(spinlock_irqsave)(&mm->context.sync_tlb_lock); 169 170 if (mm->context.sync_tlb_range_to == 0) 171 return 0; 172 173 ops.mm_idp = &mm->context.id; 174 if (mm == &init_mm) { 175 ops.mmap = kern_map; 176 ops.unmap = kern_unmap; 177 } else { 178 ops.mmap = map; 179 ops.unmap = unmap; 180 } 181 182 addr = mm->context.sync_tlb_range_from; 183 pgd = pgd_offset(mm, addr); 184 do { 185 next = pgd_addr_end(addr, mm->context.sync_tlb_range_to); 186 if (!pgd_present(*pgd)) { 187 if (pgd_needsync(*pgd)) { 188 ret = ops.unmap(ops.mm_idp, addr, 189 next - addr); 190 pgd_mkuptodate(*pgd); 191 } 192 } else 193 ret = update_p4d_range(pgd, addr, next, &ops); 194 } while (pgd++, addr = next, 195 ((addr < mm->context.sync_tlb_range_to) && !ret)); 196 197 if (ret == -ENOMEM) 198 report_enomem(); 199 200 mm->context.sync_tlb_range_from = 0; 201 mm->context.sync_tlb_range_to = 0; 202 203 return ret; 204 } 205 206 void flush_tlb_all(void) 207 { 208 /* 209 * Don't bother flushing if this address space is about to be 210 * destroyed. 211 */ 212 if (atomic_read(¤t->mm->mm_users) == 0) 213 return; 214 215 flush_tlb_mm(current->mm); 216 } 217 218 void flush_tlb_mm(struct mm_struct *mm) 219 { 220 struct vm_area_struct *vma; 221 VMA_ITERATOR(vmi, mm, 0); 222 223 for_each_vma(vmi, vma) 224 um_tlb_mark_sync(mm, vma->vm_start, vma->vm_end); 225 } 226