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
kern_map(struct mm_id * mm_idp,unsigned long virt,unsigned long len,int prot,int phys_fd,unsigned long long offset)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
kern_unmap(struct mm_id * mm_idp,unsigned long virt,unsigned long len)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
report_enomem(void)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
update_pte_range(pmd_t * pmd,unsigned long addr,unsigned long end,struct vm_ops * ops)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
update_pmd_range(pud_t * pud,unsigned long addr,unsigned long end,struct vm_ops * ops)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
update_pud_range(p4d_t * p4d,unsigned long addr,unsigned long end,struct vm_ops * ops)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
update_p4d_range(pgd_t * pgd,unsigned long addr,unsigned long end,struct vm_ops * ops)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
um_tlb_sync(struct mm_struct * mm)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
flush_tlb_all(void)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
flush_tlb_mm(struct mm_struct * mm)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