2 #include <linux/highmem.h>
3 #include <linux/sched.h>
4 #include <linux/hugetlb.h>
6 static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
12 pte = pte_offset_map(pmd, addr);
14 err = walk->pte_entry(pte, addr, addr + PAGE_SIZE, walk);
27 static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
34 pmd = pmd_offset(pud, addr);
37 next = pmd_addr_end(addr, end);
38 if (pmd_none(*pmd) || !walk->vma) {
40 err = walk->pte_hole(addr, next, walk);
46 * This implies that each ->pmd_entry() handler
47 * needs to know about pmd_trans_huge() pmds
50 err = walk->pmd_entry(pmd, addr, next, walk);
55 * Check this here so we only break down trans_huge
56 * pages when we _need_ to
61 split_huge_pmd(walk->vma, pmd, addr);
62 if (pmd_trans_unstable(pmd))
64 err = walk_pte_range(pmd, addr, next, walk);
67 } while (pmd++, addr = next, addr != end);
72 static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end,
79 pud = pud_offset(pgd, addr);
82 next = pud_addr_end(addr, end);
83 if (pud_none(*pud) || !walk->vma) {
85 err = walk->pte_hole(addr, next, walk);
91 if (walk->pud_entry) {
92 spinlock_t *ptl = pud_trans_huge_lock(pud, walk->vma);
95 err = walk->pud_entry(pud, addr, next, walk);
103 split_huge_pud(walk->vma, pud, addr);
107 if (walk->pmd_entry || walk->pte_entry)
108 err = walk_pmd_range(pud, addr, next, walk);
111 } while (pud++, addr = next, addr != end);
116 static int walk_pgd_range(unsigned long addr, unsigned long end,
117 struct mm_walk *walk)
123 pgd = pgd_offset(walk->mm, addr);
125 next = pgd_addr_end(addr, end);
126 if (pgd_none_or_clear_bad(pgd)) {
128 err = walk->pte_hole(addr, next, walk);
133 if (walk->pmd_entry || walk->pte_entry)
134 err = walk_pud_range(pgd, addr, next, walk);
137 } while (pgd++, addr = next, addr != end);
142 #ifdef CONFIG_HUGETLB_PAGE
143 static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr,
146 unsigned long boundary = (addr & huge_page_mask(h)) + huge_page_size(h);
147 return boundary < end ? boundary : end;
150 static int walk_hugetlb_range(unsigned long addr, unsigned long end,
151 struct mm_walk *walk)
153 struct vm_area_struct *vma = walk->vma;
154 struct hstate *h = hstate_vma(vma);
156 unsigned long hmask = huge_page_mask(h);
161 next = hugetlb_entry_end(h, addr, end);
162 pte = huge_pte_offset(walk->mm, addr & hmask);
163 if (pte && walk->hugetlb_entry)
164 err = walk->hugetlb_entry(pte, hmask, addr, next, walk);
167 } while (addr = next, addr != end);
172 #else /* CONFIG_HUGETLB_PAGE */
173 static int walk_hugetlb_range(unsigned long addr, unsigned long end,
174 struct mm_walk *walk)
179 #endif /* CONFIG_HUGETLB_PAGE */
182 * Decide whether we really walk over the current vma on [@start, @end)
183 * or skip it via the returned value. Return 0 if we do walk over the
184 * current vma, and return 1 if we skip the vma. Negative values means
185 * error, where we abort the current walk.
187 static int walk_page_test(unsigned long start, unsigned long end,
188 struct mm_walk *walk)
190 struct vm_area_struct *vma = walk->vma;
193 return walk->test_walk(start, end, walk);
196 * vma(VM_PFNMAP) doesn't have any valid struct pages behind VM_PFNMAP
197 * range, so we don't walk over it as we do for normal vmas. However,
198 * Some callers are interested in handling hole range and they don't
199 * want to just ignore any single address range. Such users certainly
200 * define their ->pte_hole() callbacks, so let's delegate them to handle
203 if (vma->vm_flags & VM_PFNMAP) {
206 err = walk->pte_hole(start, end, walk);
207 return err ? err : 1;
212 static int __walk_page_range(unsigned long start, unsigned long end,
213 struct mm_walk *walk)
216 struct vm_area_struct *vma = walk->vma;
218 if (vma && is_vm_hugetlb_page(vma)) {
219 if (walk->hugetlb_entry)
220 err = walk_hugetlb_range(start, end, walk);
222 err = walk_pgd_range(start, end, walk);
228 * walk_page_range - walk page table with caller specific callbacks
230 * Recursively walk the page table tree of the process represented by @walk->mm
231 * within the virtual address range [@start, @end). During walking, we can do
232 * some caller-specific works for each entry, by setting up pmd_entry(),
233 * pte_entry(), and/or hugetlb_entry(). If you don't set up for some of these
234 * callbacks, the associated entries/pages are just ignored.
235 * The return values of these callbacks are commonly defined like below:
236 * - 0 : succeeded to handle the current entry, and if you don't reach the
237 * end address yet, continue to walk.
238 * - >0 : succeeded to handle the current entry, and return to the caller
239 * with caller specific value.
240 * - <0 : failed to handle the current entry, and return to the caller
243 * Before starting to walk page table, some callers want to check whether
244 * they really want to walk over the current vma, typically by checking
245 * its vm_flags. walk_page_test() and @walk->test_walk() are used for this
248 * struct mm_walk keeps current values of some common data like vma and pmd,
249 * which are useful for the access from callbacks. If you want to pass some
250 * caller-specific data to callbacks, @walk->private should be helpful.
253 * Callers of walk_page_range() and walk_page_vma() should hold
254 * @walk->mm->mmap_sem, because these function traverse vma list and/or
255 * access to vma's data.
257 int walk_page_range(unsigned long start, unsigned long end,
258 struct mm_walk *walk)
262 struct vm_area_struct *vma;
270 VM_BUG_ON_MM(!rwsem_is_locked(&walk->mm->mmap_sem), walk->mm);
272 vma = find_vma(walk->mm, start);
274 if (!vma) { /* after the last vma */
277 } else if (start < vma->vm_start) { /* outside vma */
279 next = min(end, vma->vm_start);
280 } else { /* inside vma */
282 next = min(end, vma->vm_end);
285 err = walk_page_test(start, next, walk);
288 * positive return values are purely for
289 * controlling the pagewalk, so should never
290 * be passed to the callers.
298 if (walk->vma || walk->pte_hole)
299 err = __walk_page_range(start, next, walk);
302 } while (start = next, start < end);
306 int walk_page_vma(struct vm_area_struct *vma, struct mm_walk *walk)
313 VM_BUG_ON(!rwsem_is_locked(&walk->mm->mmap_sem));
316 err = walk_page_test(vma->vm_start, vma->vm_end, walk);
321 return __walk_page_range(vma->vm_start, vma->vm_end, walk);