1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2024 Loongson Technology Corporation Limited
4 */
5
6 #include <linux/pagewalk.h>
7 #include <linux/pgtable.h>
8 #include <asm/set_memory.h>
9 #include <asm/tlbflush.h>
10
11 struct pageattr_masks {
12 pgprot_t set_mask;
13 pgprot_t clear_mask;
14 };
15
16 static unsigned long set_pageattr_masks(unsigned long val, struct mm_walk *walk)
17 {
18 unsigned long new_val = val;
19 struct pageattr_masks *masks = walk->private;
20
21 new_val &= ~(pgprot_val(masks->clear_mask));
22 new_val |= (pgprot_val(masks->set_mask));
23
24 return new_val;
25 }
26
27 static int pageattr_pgd_entry(pgd_t *pgd, unsigned long addr,
28 unsigned long next, struct mm_walk *walk)
29 {
30 pgd_t val = pgdp_get(pgd);
31
32 if (pgd_leaf(val)) {
33 val = __pgd(set_pageattr_masks(pgd_val(val), walk));
34 set_pgd(pgd, val);
35 }
36
37 return 0;
38 }
39
40 static int pageattr_p4d_entry(p4d_t *p4d, unsigned long addr,
41 unsigned long next, struct mm_walk *walk)
42 {
43 p4d_t val = p4dp_get(p4d);
44
45 if (p4d_leaf(val)) {
46 val = __p4d(set_pageattr_masks(p4d_val(val), walk));
47 set_p4d(p4d, val);
48 }
49
50 return 0;
51 }
52
53 static int pageattr_pud_entry(pud_t *pud, unsigned long addr,
54 unsigned long next, struct mm_walk *walk)
55 {
56 pud_t val = pudp_get(pud);
57
58 if (pud_leaf(val)) {
59 val = __pud(set_pageattr_masks(pud_val(val), walk));
60 set_pud(pud, val);
61 }
62
63 return 0;
64 }
65
66 static int pageattr_pmd_entry(pmd_t *pmd, unsigned long addr,
67 unsigned long next, struct mm_walk *walk)
68 {
69 pmd_t val = pmdp_get(pmd);
70
71 if (pmd_leaf(val)) {
72 val = __pmd(set_pageattr_masks(pmd_val(val), walk));
73 set_pmd(pmd, val);
74 }
75
76 return 0;
77 }
78
79 static int pageattr_pte_entry(pte_t *pte, unsigned long addr,
80 unsigned long next, struct mm_walk *walk)
81 {
82 pte_t val = ptep_get(pte);
83
84 val = __pte(set_pageattr_masks(pte_val(val), walk));
85 set_pte(pte, val);
86
87 return 0;
88 }
89
90 static int pageattr_pte_hole(unsigned long addr, unsigned long next,
91 int depth, struct mm_walk *walk)
92 {
93 return 0;
94 }
95
96 static const struct mm_walk_ops pageattr_ops = {
97 .pgd_entry = pageattr_pgd_entry,
98 .p4d_entry = pageattr_p4d_entry,
99 .pud_entry = pageattr_pud_entry,
100 .pmd_entry = pageattr_pmd_entry,
101 .pte_entry = pageattr_pte_entry,
102 .pte_hole = pageattr_pte_hole,
103 .walk_lock = PGWALK_RDLOCK,
104 };
105
106 static int __set_memory(unsigned long addr, int numpages, pgprot_t set_mask, pgprot_t clear_mask)
107 {
108 int ret;
109 unsigned long start = addr;
110 unsigned long end = start + PAGE_SIZE * numpages;
111 struct pageattr_masks masks = {
112 .set_mask = set_mask,
113 .clear_mask = clear_mask
114 };
115
116 if (!numpages)
117 return 0;
118
119 mmap_write_lock(&init_mm);
120 ret = walk_page_range_novma(&init_mm, start, end, &pageattr_ops, NULL, &masks);
121 mmap_write_unlock(&init_mm);
122
123 flush_tlb_kernel_range(start, end);
124
125 return ret;
126 }
127
128 int set_memory_x(unsigned long addr, int numpages)
129 {
130 if (addr < vm_map_base)
131 return 0;
132
133 return __set_memory(addr, numpages, __pgprot(0), __pgprot(_PAGE_NO_EXEC));
134 }
135
136 int set_memory_nx(unsigned long addr, int numpages)
137 {
138 if (addr < vm_map_base)
139 return 0;
140
141 return __set_memory(addr, numpages, __pgprot(_PAGE_NO_EXEC), __pgprot(0));
142 }
143
144 int set_memory_ro(unsigned long addr, int numpages)
145 {
146 if (addr < vm_map_base)
147 return 0;
148
149 return __set_memory(addr, numpages, __pgprot(0), __pgprot(_PAGE_WRITE | _PAGE_DIRTY));
150 }
151
152 int set_memory_rw(unsigned long addr, int numpages)
153 {
154 if (addr < vm_map_base)
155 return 0;
156
157 return __set_memory(addr, numpages, __pgprot(_PAGE_WRITE | _PAGE_DIRTY), __pgprot(0));
158 }
159
160 bool kernel_page_present(struct page *page)
161 {
162 pgd_t *pgd;
163 p4d_t *p4d;
164 pud_t *pud;
165 pmd_t *pmd;
166 pte_t *pte;
167 unsigned long addr = (unsigned long)page_address(page);
168
169 if (addr < vm_map_base)
170 return true;
171
172 pgd = pgd_offset_k(addr);
173 if (pgd_none(pgdp_get(pgd)))
174 return false;
175 if (pgd_leaf(pgdp_get(pgd)))
176 return true;
177
178 p4d = p4d_offset(pgd, addr);
179 if (p4d_none(p4dp_get(p4d)))
180 return false;
181 if (p4d_leaf(p4dp_get(p4d)))
182 return true;
183
184 pud = pud_offset(p4d, addr);
185 if (pud_none(pudp_get(pud)))
186 return false;
187 if (pud_leaf(pudp_get(pud)))
188 return true;
189
190 pmd = pmd_offset(pud, addr);
191 if (pmd_none(pmdp_get(pmd)))
192 return false;
193 if (pmd_leaf(pmdp_get(pmd)))
194 return true;
195
196 pte = pte_offset_kernel(pmd, addr);
197 return pte_present(ptep_get(pte));
198 }
199
200 int set_direct_map_default_noflush(struct page *page)
201 {
202 unsigned long addr = (unsigned long)page_address(page);
203
204 if (addr < vm_map_base)
205 return 0;
206
207 return __set_memory(addr, 1, PAGE_KERNEL, __pgprot(0));
208 }
209
210 int set_direct_map_invalid_noflush(struct page *page)
211 {
212 unsigned long addr = (unsigned long)page_address(page);
213
214 if (addr < vm_map_base)
215 return 0;
216
217 return __set_memory(addr, 1, __pgprot(0), __pgprot(_PAGE_PRESENT | _PAGE_VALID));
218 }
219
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