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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
18struct 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
28static 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
37static 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
43void 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
50static 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
91static 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
114static 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
137static 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
160int 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
206void 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(&current->mm->mm_users) == 0)
213 return;
214
215 flush_tlb_mm(current->mm);
216}
217
218void 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}