thp: add pmd mangling generic functions
Some are needed to build but not actually used on archs not supporting
transparent hugepages. Others like pmdp_clear_flush are used by x86 too.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
new file mode 100644
index 0000000..d030548
--- /dev/null
+++ b/mm/pgtable-generic.c
@@ -0,0 +1,123 @@
+/*
+ * mm/pgtable-generic.c
+ *
+ * Generic pgtable methods declared in asm-generic/pgtable.h
+ *
+ * Copyright (C) 2010 Linus Torvalds
+ */
+
+#include <asm/tlb.h>
+#include <asm-generic/pgtable.h>
+
+#ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
+/*
+ * Only sets the access flags (dirty, accessed, and
+ * writable). Furthermore, we know it always gets set to a "more
+ * permissive" setting, which allows most architectures to optimize
+ * this. We return whether the PTE actually changed, which in turn
+ * instructs the caller to do things like update__mmu_cache. This
+ * used to be done in the caller, but sparc needs minor faults to
+ * force that call on sun4c so we changed this macro slightly
+ */
+int ptep_set_access_flags(struct vm_area_struct *vma,
+ unsigned long address, pte_t *ptep,
+ pte_t entry, int dirty)
+{
+ int changed = !pte_same(*ptep, entry);
+ if (changed) {
+ set_pte_at(vma->vm_mm, address, ptep, entry);
+ flush_tlb_page(vma, address);
+ }
+ return changed;
+}
+#endif
+
+#ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
+int pmdp_set_access_flags(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp,
+ pmd_t entry, int dirty)
+{
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ int changed = !pmd_same(*pmdp, entry);
+ VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+ if (changed) {
+ set_pmd_at(vma->vm_mm, address, pmdp, entry);
+ flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
+ }
+ return changed;
+#else /* CONFIG_TRANSPARENT_HUGEPAGE */
+ BUG();
+ return 0;
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+}
+#endif
+
+#ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
+int ptep_clear_flush_young(struct vm_area_struct *vma,
+ unsigned long address, pte_t *ptep)
+{
+ int young;
+ young = ptep_test_and_clear_young(vma, address, ptep);
+ if (young)
+ flush_tlb_page(vma, address);
+ return young;
+}
+#endif
+
+#ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
+int pmdp_clear_flush_young(struct vm_area_struct *vma,
+ unsigned long address, pmd_t *pmdp)
+{
+ int young;
+#ifndef CONFIG_TRANSPARENT_HUGEPAGE
+ BUG();
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+ VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+ young = pmdp_test_and_clear_young(vma, address, pmdp);
+ if (young)
+ flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
+ return young;
+}
+#endif
+
+#ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
+pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
+ pte_t *ptep)
+{
+ pte_t pte;
+ pte = ptep_get_and_clear((vma)->vm_mm, address, ptep);
+ flush_tlb_page(vma, address);
+ return pte;
+}
+#endif
+
+#ifndef __HAVE_ARCH_PMDP_CLEAR_FLUSH
+pmd_t pmdp_clear_flush(struct vm_area_struct *vma, unsigned long address,
+ pmd_t *pmdp)
+{
+ pmd_t pmd;
+#ifndef CONFIG_TRANSPARENT_HUGEPAGE
+ BUG();
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+ VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+ pmd = pmdp_get_and_clear(vma->vm_mm, address, pmdp);
+ flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
+ return pmd;
+}
+#endif
+
+#ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH
+pmd_t pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
+ pmd_t *pmdp)
+{
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ pmd_t pmd = pmd_mksplitting(*pmdp);
+ VM_BUG_ON(address & ~HPAGE_PMD_MASK);
+ set_pmd_at(vma->vm_mm, address, pmdp, pmd);
+ /* tlb flush only to serialize against gup-fast */
+ flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
+#else /* CONFIG_TRANSPARENT_HUGEPAGE */
+ BUG();
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+}
+#endif