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10#include <linux/pagemap.h>
11#include <linux/gfp.h>
12#include <linux/mm.h>
13#include <linux/mman.h>
14#include <linux/syscalls.h>
15#include <linux/swap.h>
16#include <linux/swapops.h>
17#include <linux/hugetlb.h>
18
19#include <asm/uaccess.h>
20#include <asm/pgtable.h>
21
22static void mincore_hugetlb_page_range(struct vm_area_struct *vma,
23 unsigned long addr, unsigned long end,
24 unsigned char *vec)
25{
26#ifdef CONFIG_HUGETLB_PAGE
27 struct hstate *h;
28
29 h = hstate_vma(vma);
30 while (1) {
31 unsigned char present;
32 pte_t *ptep;
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36
37 ptep = huge_pte_offset(current->mm,
38 addr & huge_page_mask(h));
39 present = ptep && !huge_pte_none(huge_ptep_get(ptep));
40 while (1) {
41 *vec = present;
42 vec++;
43 addr += PAGE_SIZE;
44 if (addr == end)
45 return;
46
47 if (!(addr & ~huge_page_mask(h)))
48 break;
49 }
50 }
51#else
52 BUG();
53#endif
54}
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61
62static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff)
63{
64 unsigned char present = 0;
65 struct page *page;
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77 page = find_get_page(mapping, pgoff);
78 if (page) {
79 present = PageUptodate(page);
80 page_cache_release(page);
81 }
82
83 return present;
84}
85
86static void mincore_unmapped_range(struct vm_area_struct *vma,
87 unsigned long addr, unsigned long end,
88 unsigned char *vec)
89{
90 unsigned long nr = (end - addr) >> PAGE_SHIFT;
91 int i;
92
93 if (vma->vm_file) {
94 pgoff_t pgoff;
95
96 pgoff = linear_page_index(vma, addr);
97 for (i = 0; i < nr; i++, pgoff++)
98 vec[i] = mincore_page(vma->vm_file->f_mapping, pgoff);
99 } else {
100 for (i = 0; i < nr; i++)
101 vec[i] = 0;
102 }
103}
104
105static void mincore_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
106 unsigned long addr, unsigned long end,
107 unsigned char *vec)
108{
109 unsigned long next;
110 spinlock_t *ptl;
111 pte_t *ptep;
112
113 ptep = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
114 do {
115 pte_t pte = *ptep;
116 pgoff_t pgoff;
117
118 next = addr + PAGE_SIZE;
119 if (pte_none(pte))
120 mincore_unmapped_range(vma, addr, next, vec);
121 else if (pte_present(pte))
122 *vec = 1;
123 else if (pte_file(pte)) {
124 pgoff = pte_to_pgoff(pte);
125 *vec = mincore_page(vma->vm_file->f_mapping, pgoff);
126 } else {
127 swp_entry_t entry = pte_to_swp_entry(pte);
128
129 if (is_migration_entry(entry)) {
130
131 *vec = 1;
132 } else {
133#ifdef CONFIG_SWAP
134 pgoff = entry.val;
135 *vec = mincore_page(&swapper_space, pgoff);
136#else
137 WARN_ON(1);
138 *vec = 1;
139#endif
140 }
141 }
142 vec++;
143 } while (ptep++, addr = next, addr != end);
144 pte_unmap_unlock(ptep - 1, ptl);
145}
146
147static void mincore_pmd_range(struct vm_area_struct *vma, pud_t *pud,
148 unsigned long addr, unsigned long end,
149 unsigned char *vec)
150{
151 unsigned long next;
152 pmd_t *pmd;
153
154 pmd = pmd_offset(pud, addr);
155 do {
156 next = pmd_addr_end(addr, end);
157 if (pmd_trans_huge(*pmd)) {
158 if (mincore_huge_pmd(vma, pmd, addr, next, vec)) {
159 vec += (next - addr) >> PAGE_SHIFT;
160 continue;
161 }
162
163 }
164 if (pmd_none_or_clear_bad(pmd))
165 mincore_unmapped_range(vma, addr, next, vec);
166 else
167 mincore_pte_range(vma, pmd, addr, next, vec);
168 vec += (next - addr) >> PAGE_SHIFT;
169 } while (pmd++, addr = next, addr != end);
170}
171
172static void mincore_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
173 unsigned long addr, unsigned long end,
174 unsigned char *vec)
175{
176 unsigned long next;
177 pud_t *pud;
178
179 pud = pud_offset(pgd, addr);
180 do {
181 next = pud_addr_end(addr, end);
182 if (pud_none_or_clear_bad(pud))
183 mincore_unmapped_range(vma, addr, next, vec);
184 else
185 mincore_pmd_range(vma, pud, addr, next, vec);
186 vec += (next - addr) >> PAGE_SHIFT;
187 } while (pud++, addr = next, addr != end);
188}
189
190static void mincore_page_range(struct vm_area_struct *vma,
191 unsigned long addr, unsigned long end,
192 unsigned char *vec)
193{
194 unsigned long next;
195 pgd_t *pgd;
196
197 pgd = pgd_offset(vma->vm_mm, addr);
198 do {
199 next = pgd_addr_end(addr, end);
200 if (pgd_none_or_clear_bad(pgd))
201 mincore_unmapped_range(vma, addr, next, vec);
202 else
203 mincore_pud_range(vma, pgd, addr, next, vec);
204 vec += (next - addr) >> PAGE_SHIFT;
205 } while (pgd++, addr = next, addr != end);
206}
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212
213static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *vec)
214{
215 struct vm_area_struct *vma;
216 unsigned long end;
217
218 vma = find_vma(current->mm, addr);
219 if (!vma || addr < vma->vm_start)
220 return -ENOMEM;
221
222 end = min(vma->vm_end, addr + (pages << PAGE_SHIFT));
223
224 if (is_vm_hugetlb_page(vma)) {
225 mincore_hugetlb_page_range(vma, addr, end, vec);
226 return (end - addr) >> PAGE_SHIFT;
227 }
228
229 end = pmd_addr_end(addr, end);
230
231 if (is_vm_hugetlb_page(vma))
232 mincore_hugetlb_page_range(vma, addr, end, vec);
233 else
234 mincore_page_range(vma, addr, end, vec);
235
236 return (end - addr) >> PAGE_SHIFT;
237}
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263SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, len,
264 unsigned char __user *, vec)
265{
266 long retval;
267 unsigned long pages;
268 unsigned char *tmp;
269
270
271 if (start & ~PAGE_CACHE_MASK)
272 return -EINVAL;
273
274
275 if (!access_ok(VERIFY_READ, (void __user *) start, len))
276 return -ENOMEM;
277
278
279 pages = len >> PAGE_SHIFT;
280 pages += (len & ~PAGE_MASK) != 0;
281
282 if (!access_ok(VERIFY_WRITE, vec, pages))
283 return -EFAULT;
284
285 tmp = (void *) __get_free_page(GFP_USER);
286 if (!tmp)
287 return -EAGAIN;
288
289 retval = 0;
290 while (pages) {
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295 down_read(¤t->mm->mmap_sem);
296 retval = do_mincore(start, min(pages, PAGE_SIZE), tmp);
297 up_read(¤t->mm->mmap_sem);
298
299 if (retval <= 0)
300 break;
301 if (copy_to_user(vec, tmp, retval)) {
302 retval = -EFAULT;
303 break;
304 }
305 pages -= retval;
306 vec += retval;
307 start += retval << PAGE_SHIFT;
308 retval = 0;
309 }
310 free_page((unsigned long) tmp);
311 return retval;
312}
313