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authorroot <root@artemis.panaceas.org>2015-12-25 04:40:36 +0000
committerroot <root@artemis.panaceas.org>2015-12-25 04:40:36 +0000
commit849369d6c66d3054688672f97d31fceb8e8230fb (patch)
tree6135abc790ca67dedbe07c39806591e70eda81ce /mm/pagewalk.c
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initial_commit
Diffstat (limited to 'mm/pagewalk.c')
-rw-r--r--mm/pagewalk.c212
1 files changed, 212 insertions, 0 deletions
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
new file mode 100644
index 00000000..87eac0ea
--- /dev/null
+++ b/mm/pagewalk.c
@@ -0,0 +1,212 @@
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <linux/sched.h>
+#include <linux/hugetlb.h>
+
+static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
+ struct mm_walk *walk)
+{
+ pte_t *pte;
+ int err = 0;
+
+ pte = pte_offset_map(pmd, addr);
+ for (;;) {
+ err = walk->pte_entry(pte, addr, addr + PAGE_SIZE, walk);
+ if (err)
+ break;
+ addr += PAGE_SIZE;
+ if (addr == end)
+ break;
+ pte++;
+ }
+
+ pte_unmap(pte);
+ return err;
+}
+
+static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
+ struct mm_walk *walk)
+{
+ pmd_t *pmd;
+ unsigned long next;
+ int err = 0;
+
+ pmd = pmd_offset(pud, addr);
+ do {
+again:
+ next = pmd_addr_end(addr, end);
+ if (pmd_none(*pmd)) {
+ if (walk->pte_hole)
+ err = walk->pte_hole(addr, next, walk);
+ if (err)
+ break;
+ continue;
+ }
+ /*
+ * This implies that each ->pmd_entry() handler
+ * needs to know about pmd_trans_huge() pmds
+ */
+ if (walk->pmd_entry)
+ err = walk->pmd_entry(pmd, addr, next, walk);
+ if (err)
+ break;
+
+ /*
+ * Check this here so we only break down trans_huge
+ * pages when we _need_ to
+ */
+ if (!walk->pte_entry)
+ continue;
+
+ split_huge_page_pmd(walk->mm, pmd);
+ if (pmd_none_or_trans_huge_or_clear_bad(pmd))
+ goto again;
+ err = walk_pte_range(pmd, addr, next, walk);
+ if (err)
+ break;
+ } while (pmd++, addr = next, addr != end);
+
+ return err;
+}
+
+static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end,
+ struct mm_walk *walk)
+{
+ pud_t *pud;
+ unsigned long next;
+ int err = 0;
+
+ pud = pud_offset(pgd, addr);
+ do {
+ next = pud_addr_end(addr, end);
+ if (pud_none_or_clear_bad(pud)) {
+ if (walk->pte_hole)
+ err = walk->pte_hole(addr, next, walk);
+ if (err)
+ break;
+ continue;
+ }
+ if (walk->pud_entry)
+ err = walk->pud_entry(pud, addr, next, walk);
+ if (!err && (walk->pmd_entry || walk->pte_entry))
+ err = walk_pmd_range(pud, addr, next, walk);
+ if (err)
+ break;
+ } while (pud++, addr = next, addr != end);
+
+ return err;
+}
+
+#ifdef CONFIG_HUGETLB_PAGE
+static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr,
+ unsigned long end)
+{
+ unsigned long boundary = (addr & huge_page_mask(h)) + huge_page_size(h);
+ return boundary < end ? boundary : end;
+}
+
+static int walk_hugetlb_range(struct vm_area_struct *vma,
+ unsigned long addr, unsigned long end,
+ struct mm_walk *walk)
+{
+ struct hstate *h = hstate_vma(vma);
+ unsigned long next;
+ unsigned long hmask = huge_page_mask(h);
+ pte_t *pte;
+ int err = 0;
+
+ do {
+ next = hugetlb_entry_end(h, addr, end);
+ pte = huge_pte_offset(walk->mm, addr & hmask);
+ if (pte && walk->hugetlb_entry)
+ err = walk->hugetlb_entry(pte, hmask, addr, next, walk);
+ if (err)
+ return err;
+ } while (addr = next, addr != end);
+
+ return 0;
+}
+#endif
+
+/**
+ * walk_page_range - walk a memory map's page tables with a callback
+ * @mm: memory map to walk
+ * @addr: starting address
+ * @end: ending address
+ * @walk: set of callbacks to invoke for each level of the tree
+ *
+ * Recursively walk the page table for the memory area in a VMA,
+ * calling supplied callbacks. Callbacks are called in-order (first
+ * PGD, first PUD, first PMD, first PTE, second PTE... second PMD,
+ * etc.). If lower-level callbacks are omitted, walking depth is reduced.
+ *
+ * Each callback receives an entry pointer and the start and end of the
+ * associated range, and a copy of the original mm_walk for access to
+ * the ->private or ->mm fields.
+ *
+ * No locks are taken, but the bottom level iterator will map PTE
+ * directories from highmem if necessary.
+ *
+ * If any callback returns a non-zero value, the walk is aborted and
+ * the return value is propagated back to the caller. Otherwise 0 is returned.
+ */
+int walk_page_range(unsigned long addr, unsigned long end,
+ struct mm_walk *walk)
+{
+ pgd_t *pgd;
+ unsigned long next;
+ int err = 0;
+
+ if (addr >= end)
+ return err;
+
+ if (!walk->mm)
+ return -EINVAL;
+
+ pgd = pgd_offset(walk->mm, addr);
+ do {
+ struct vm_area_struct *uninitialized_var(vma);
+
+ next = pgd_addr_end(addr, end);
+
+#ifdef CONFIG_HUGETLB_PAGE
+ /*
+ * handle hugetlb vma individually because pagetable walk for
+ * the hugetlb page is dependent on the architecture and
+ * we can't handled it in the same manner as non-huge pages.
+ */
+ vma = find_vma(walk->mm, addr);
+ if (vma && is_vm_hugetlb_page(vma)) {
+ if (vma->vm_end < next)
+ next = vma->vm_end;
+ /*
+ * Hugepage is very tightly coupled with vma, so
+ * walk through hugetlb entries within a given vma.
+ */
+ err = walk_hugetlb_range(vma, addr, next, walk);
+ if (err)
+ break;
+ pgd = pgd_offset(walk->mm, next);
+ continue;
+ }
+#endif
+ if (pgd_none_or_clear_bad(pgd)) {
+ if (walk->pte_hole)
+ err = walk->pte_hole(addr, next, walk);
+ if (err)
+ break;
+ pgd++;
+ continue;
+ }
+ if (walk->pgd_entry)
+ err = walk->pgd_entry(pgd, addr, next, walk);
+ if (!err &&
+ (walk->pud_entry || walk->pmd_entry || walk->pte_entry))
+ err = walk_pud_range(pgd, addr, next, walk);
+ if (err)
+ break;
+ pgd++;
+ } while (addr = next, addr != end);
+
+ return err;
+}