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11#include <linux/pagemap.h>
12#include <linux/gfp.h>
13#include <linux/mm.h>
14#include <linux/mman.h>
15#include <linux/syscalls.h>
16#include <linux/swap.h>
17#include <linux/swapops.h>
18#include <linux/shmem_fs.h>
19#include <linux/hugetlb.h>
20
21#include <linux/uaccess.h>
22#include <asm/pgtable.h>
23
24static int mincore_hugetlb(pte_t *pte, unsigned long hmask, unsigned long addr,
25 unsigned long end, struct mm_walk *walk)
26{
27#ifdef CONFIG_HUGETLB_PAGE
28 unsigned char present;
29 unsigned char *vec = walk->private;
30
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33
34
35 present = pte && !huge_pte_none(huge_ptep_get(pte));
36 for (; addr != end; vec++, addr += PAGE_SIZE)
37 *vec = present;
38 walk->private = vec;
39#else
40 BUG();
41#endif
42 return 0;
43}
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50
51static unsigned char mincore_page(struct address_space *mapping, pgoff_t pgoff)
52{
53 unsigned char present = 0;
54 struct page *page;
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61
62#ifdef CONFIG_SWAP
63 if (shmem_mapping(mapping)) {
64 page = find_get_entry(mapping, pgoff);
65
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67
68
69 if (radix_tree_exceptional_entry(page)) {
70 swp_entry_t swp = radix_to_swp_entry(page);
71 page = find_get_page(swap_address_space(swp),
72 swp_offset(swp));
73 }
74 } else
75 page = find_get_page(mapping, pgoff);
76#else
77 page = find_get_page(mapping, pgoff);
78#endif
79 if (page) {
80 present = PageUptodate(page);
81 put_page(page);
82 }
83
84 return present;
85}
86
87static int __mincore_unmapped_range(unsigned long addr, unsigned long end,
88 struct vm_area_struct *vma, 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 return nr;
104}
105
106static int mincore_unmapped_range(unsigned long addr, unsigned long end,
107 struct mm_walk *walk)
108{
109 walk->private += __mincore_unmapped_range(addr, end,
110 walk->vma, walk->private);
111 return 0;
112}
113
114static int mincore_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
115 struct mm_walk *walk)
116{
117 spinlock_t *ptl;
118 struct vm_area_struct *vma = walk->vma;
119 pte_t *ptep;
120 unsigned char *vec = walk->private;
121 int nr = (end - addr) >> PAGE_SHIFT;
122
123 ptl = pmd_trans_huge_lock(pmd, vma);
124 if (ptl) {
125 memset(vec, 1, nr);
126 spin_unlock(ptl);
127 goto out;
128 }
129
130 if (pmd_trans_unstable(pmd)) {
131 __mincore_unmapped_range(addr, end, vma, vec);
132 goto out;
133 }
134
135 ptep = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);
136 for (; addr != end; ptep++, addr += PAGE_SIZE) {
137 pte_t pte = *ptep;
138
139 if (pte_none(pte))
140 __mincore_unmapped_range(addr, addr + PAGE_SIZE,
141 vma, vec);
142 else if (pte_present(pte))
143 *vec = 1;
144 else {
145 swp_entry_t entry = pte_to_swp_entry(pte);
146
147 if (non_swap_entry(entry)) {
148
149
150
151
152 *vec = 1;
153 } else {
154#ifdef CONFIG_SWAP
155 *vec = mincore_page(swap_address_space(entry),
156 swp_offset(entry));
157#else
158 WARN_ON(1);
159 *vec = 1;
160#endif
161 }
162 }
163 vec++;
164 }
165 pte_unmap_unlock(ptep - 1, ptl);
166out:
167 walk->private += nr;
168 cond_resched();
169 return 0;
170}
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176
177static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *vec)
178{
179 struct vm_area_struct *vma;
180 unsigned long end;
181 int err;
182 struct mm_walk mincore_walk = {
183 .pmd_entry = mincore_pte_range,
184 .pte_hole = mincore_unmapped_range,
185 .hugetlb_entry = mincore_hugetlb,
186 .private = vec,
187 };
188
189 vma = find_vma(current->mm, addr);
190 if (!vma || addr < vma->vm_start)
191 return -ENOMEM;
192 mincore_walk.mm = vma->vm_mm;
193 end = min(vma->vm_end, addr + (pages << PAGE_SHIFT));
194 err = walk_page_range(addr, end, &mincore_walk);
195 if (err < 0)
196 return err;
197 return (end - addr) >> PAGE_SHIFT;
198}
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224SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, len,
225 unsigned char __user *, vec)
226{
227 long retval;
228 unsigned long pages;
229 unsigned char *tmp;
230
231
232 if (start & ~PAGE_MASK)
233 return -EINVAL;
234
235
236 if (!access_ok(VERIFY_READ, (void __user *) start, len))
237 return -ENOMEM;
238
239
240 pages = len >> PAGE_SHIFT;
241 pages += (offset_in_page(len)) != 0;
242
243 if (!access_ok(VERIFY_WRITE, vec, pages))
244 return -EFAULT;
245
246 tmp = (void *) __get_free_page(GFP_USER);
247 if (!tmp)
248 return -EAGAIN;
249
250 retval = 0;
251 while (pages) {
252
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255
256 down_read(¤t->mm->mmap_sem);
257 retval = do_mincore(start, min(pages, PAGE_SIZE), tmp);
258 up_read(¤t->mm->mmap_sem);
259
260 if (retval <= 0)
261 break;
262 if (copy_to_user(vec, tmp, retval)) {
263 retval = -EFAULT;
264 break;
265 }
266 pages -= retval;
267 vec += retval;
268 start += retval << PAGE_SHIFT;
269 retval = 0;
270 }
271 free_page((unsigned long) tmp);
272 return retval;
273}
274