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5#include <linux/kernel.h>
6#include <linux/mm.h>
7#include <linux/module.h>
8#include <linux/sched.h>
9#include <linux/vmalloc.h>
10
11#include <asm/cacheflush.h>
12#include <asm/set_memory.h>
13#include <asm/tlbflush.h>
14
15struct page_change_data {
16 pgprot_t set_mask;
17 pgprot_t clear_mask;
18};
19
20bool rodata_full __ro_after_init = IS_ENABLED(CONFIG_RODATA_FULL_DEFAULT_ENABLED);
21
22bool can_set_direct_map(void)
23{
24 return rodata_full || debug_pagealloc_enabled();
25}
26
27static int change_page_range(pte_t *ptep, unsigned long addr, void *data)
28{
29 struct page_change_data *cdata = data;
30 pte_t pte = READ_ONCE(*ptep);
31
32 pte = clear_pte_bit(pte, cdata->clear_mask);
33 pte = set_pte_bit(pte, cdata->set_mask);
34
35 set_pte(ptep, pte);
36 return 0;
37}
38
39
40
41
42static int __change_memory_common(unsigned long start, unsigned long size,
43 pgprot_t set_mask, pgprot_t clear_mask)
44{
45 struct page_change_data data;
46 int ret;
47
48 data.set_mask = set_mask;
49 data.clear_mask = clear_mask;
50
51 ret = apply_to_page_range(&init_mm, start, size, change_page_range,
52 &data);
53
54 flush_tlb_kernel_range(start, start + size);
55 return ret;
56}
57
58static int change_memory_common(unsigned long addr, int numpages,
59 pgprot_t set_mask, pgprot_t clear_mask)
60{
61 unsigned long start = addr;
62 unsigned long size = PAGE_SIZE * numpages;
63 unsigned long end = start + size;
64 struct vm_struct *area;
65 int i;
66
67 if (!PAGE_ALIGNED(addr)) {
68 start &= PAGE_MASK;
69 end = start + size;
70 WARN_ON_ONCE(1);
71 }
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84
85
86 area = find_vm_area((void *)addr);
87 if (!area ||
88 end > (unsigned long)area->addr + area->size ||
89 !(area->flags & VM_ALLOC))
90 return -EINVAL;
91
92 if (!numpages)
93 return 0;
94
95
96
97
98
99 if (rodata_full && (pgprot_val(set_mask) == PTE_RDONLY ||
100 pgprot_val(clear_mask) == PTE_RDONLY)) {
101 for (i = 0; i < area->nr_pages; i++) {
102 __change_memory_common((u64)page_address(area->pages[i]),
103 PAGE_SIZE, set_mask, clear_mask);
104 }
105 }
106
107
108
109
110
111 vm_unmap_aliases();
112
113 return __change_memory_common(start, size, set_mask, clear_mask);
114}
115
116int set_memory_ro(unsigned long addr, int numpages)
117{
118 return change_memory_common(addr, numpages,
119 __pgprot(PTE_RDONLY),
120 __pgprot(PTE_WRITE));
121}
122
123int set_memory_rw(unsigned long addr, int numpages)
124{
125 return change_memory_common(addr, numpages,
126 __pgprot(PTE_WRITE),
127 __pgprot(PTE_RDONLY));
128}
129
130int set_memory_nx(unsigned long addr, int numpages)
131{
132 return change_memory_common(addr, numpages,
133 __pgprot(PTE_PXN),
134 __pgprot(PTE_MAYBE_GP));
135}
136
137int set_memory_x(unsigned long addr, int numpages)
138{
139 return change_memory_common(addr, numpages,
140 __pgprot(PTE_MAYBE_GP),
141 __pgprot(PTE_PXN));
142}
143
144int set_memory_valid(unsigned long addr, int numpages, int enable)
145{
146 if (enable)
147 return __change_memory_common(addr, PAGE_SIZE * numpages,
148 __pgprot(PTE_VALID),
149 __pgprot(0));
150 else
151 return __change_memory_common(addr, PAGE_SIZE * numpages,
152 __pgprot(0),
153 __pgprot(PTE_VALID));
154}
155
156int set_direct_map_invalid_noflush(struct page *page)
157{
158 struct page_change_data data = {
159 .set_mask = __pgprot(0),
160 .clear_mask = __pgprot(PTE_VALID),
161 };
162
163 if (!can_set_direct_map())
164 return 0;
165
166 return apply_to_page_range(&init_mm,
167 (unsigned long)page_address(page),
168 PAGE_SIZE, change_page_range, &data);
169}
170
171int set_direct_map_default_noflush(struct page *page)
172{
173 struct page_change_data data = {
174 .set_mask = __pgprot(PTE_VALID | PTE_WRITE),
175 .clear_mask = __pgprot(PTE_RDONLY),
176 };
177
178 if (!can_set_direct_map())
179 return 0;
180
181 return apply_to_page_range(&init_mm,
182 (unsigned long)page_address(page),
183 PAGE_SIZE, change_page_range, &data);
184}
185
186#ifdef CONFIG_DEBUG_PAGEALLOC
187void __kernel_map_pages(struct page *page, int numpages, int enable)
188{
189 if (!can_set_direct_map())
190 return;
191
192 set_memory_valid((unsigned long)page_address(page), numpages, enable);
193}
194#endif
195
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203
204
205bool kernel_page_present(struct page *page)
206{
207 pgd_t *pgdp;
208 p4d_t *p4dp;
209 pud_t *pudp, pud;
210 pmd_t *pmdp, pmd;
211 pte_t *ptep;
212 unsigned long addr = (unsigned long)page_address(page);
213
214 if (!can_set_direct_map())
215 return true;
216
217 pgdp = pgd_offset_k(addr);
218 if (pgd_none(READ_ONCE(*pgdp)))
219 return false;
220
221 p4dp = p4d_offset(pgdp, addr);
222 if (p4d_none(READ_ONCE(*p4dp)))
223 return false;
224
225 pudp = pud_offset(p4dp, addr);
226 pud = READ_ONCE(*pudp);
227 if (pud_none(pud))
228 return false;
229 if (pud_sect(pud))
230 return true;
231
232 pmdp = pmd_offset(pudp, addr);
233 pmd = READ_ONCE(*pmdp);
234 if (pmd_none(pmd))
235 return false;
236 if (pmd_sect(pmd))
237 return true;
238
239 ptep = pte_offset_kernel(pmdp, addr);
240 return pte_valid(READ_ONCE(*ptep));
241}
242