thp: add x86 32bit support

Add support for transparent hugepages to x86 32bit.

Share the same VM_ bitflag for VM_MAPPED_COPY.  mm/nommu.c will never
support transparent hugepages.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 117 insertions, 0 deletions

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 3278038e9706..001a3831567a 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -97,6 +97,11 @@ static inline int pte_young(pte_t pte)
         return pte_flags(pte) & _PAGE_ACCESSED;
 }
 
+static inline int pmd_young(pmd_t pmd)
+{
+        return pmd_flags(pmd) & _PAGE_ACCESSED;
+}
+
 static inline int pte_write(pte_t pte)
 {
         return pte_flags(pte) & _PAGE_RW;
@@ -145,6 +150,18 @@ static inline int pmd_large(pmd_t pte)
                 (_PAGE_PSE | _PAGE_PRESENT);
 }
 
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static inline int pmd_trans_splitting(pmd_t pmd)
+{
+        return pmd_val(pmd) & _PAGE_SPLITTING;
+}
+
+static inline int pmd_trans_huge(pmd_t pmd)
+{
+        return pmd_val(pmd) & _PAGE_PSE;
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
 static inline pte_t pte_set_flags(pte_t pte, pteval_t set)
 {
         pteval_t v = native_pte_val(pte);
@@ -219,6 +236,55 @@ static inline pte_t pte_mkspecial(pte_t pte)
         return pte_set_flags(pte, _PAGE_SPECIAL);
 }
 
+static inline pmd_t pmd_set_flags(pmd_t pmd, pmdval_t set)
+{
+        pmdval_t v = native_pmd_val(pmd);
+
+        return __pmd(v | set);
+}
+
+static inline pmd_t pmd_clear_flags(pmd_t pmd, pmdval_t clear)
+{
+        pmdval_t v = native_pmd_val(pmd);
+
+        return __pmd(v & ~clear);
+}
+
+static inline pmd_t pmd_mkold(pmd_t pmd)
+{
+        return pmd_clear_flags(pmd, _PAGE_ACCESSED);
+}
+
+static inline pmd_t pmd_wrprotect(pmd_t pmd)
+{
+        return pmd_clear_flags(pmd, _PAGE_RW);
+}
+
+static inline pmd_t pmd_mkdirty(pmd_t pmd)
+{
+        return pmd_set_flags(pmd, _PAGE_DIRTY);
+}
+
+static inline pmd_t pmd_mkhuge(pmd_t pmd)
+{
+        return pmd_set_flags(pmd, _PAGE_PSE);
+}
+
+static inline pmd_t pmd_mkyoung(pmd_t pmd)
+{
+        return pmd_set_flags(pmd, _PAGE_ACCESSED);
+}
+
+static inline pmd_t pmd_mkwrite(pmd_t pmd)
+{
+        return pmd_set_flags(pmd, _PAGE_RW);
+}
+
+static inline pmd_t pmd_mknotpresent(pmd_t pmd)
+{
+        return pmd_clear_flags(pmd, _PAGE_PRESENT);
+}
+
 /*
  * Mask out unsupported bits in a present pgprot.  Non-present pgprots
  * can use those bits for other purposes, so leave them be.
@@ -527,6 +593,14 @@ static inline pte_t native_local_ptep_get_and_clear(pte_t *ptep)
         return res;
 }
 
+static inline pmd_t native_local_pmdp_get_and_clear(pmd_t *pmdp)
+{
+        pmd_t res = *pmdp;
+
+        native_pmd_clear(pmdp);
+        return res;
+}
+
 static inline void native_set_pte_at(struct mm_struct *mm, unsigned long addr,
                                      pte_t *ptep , pte_t pte)
 {
@@ -616,6 +690,49 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm,
 
 #define flush_tlb_fix_spurious_fault(vma, address)
 
+#define mk_pmd(page, pgprot)   pfn_pmd(page_to_pfn(page), (pgprot))
+
+#define  __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
+extern int pmdp_set_access_flags(struct vm_area_struct *vma,
+                                 unsigned long address, pmd_t *pmdp,
+                                 pmd_t entry, int dirty);
+
+#define __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG
+extern int pmdp_test_and_clear_young(struct vm_area_struct *vma,
+                                     unsigned long addr, pmd_t *pmdp);
+
+#define __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
+extern int pmdp_clear_flush_young(struct vm_area_struct *vma,
+                                  unsigned long address, pmd_t *pmdp);
+
+
+#define __HAVE_ARCH_PMDP_SPLITTING_FLUSH
+extern void pmdp_splitting_flush(struct vm_area_struct *vma,
+                                 unsigned long addr, pmd_t *pmdp);
+
+#define __HAVE_ARCH_PMD_WRITE
+static inline int pmd_write(pmd_t pmd)
+{
+        return pmd_flags(pmd) & _PAGE_RW;
+}
+
+#define __HAVE_ARCH_PMDP_GET_AND_CLEAR
+static inline pmd_t pmdp_get_and_clear(struct mm_struct *mm, unsigned long addr,
+                                       pmd_t *pmdp)
+{
+        pmd_t pmd = native_pmdp_get_and_clear(pmdp);
+        pmd_update(mm, addr, pmdp);
+        return pmd;
+}
+
+#define __HAVE_ARCH_PMDP_SET_WRPROTECT
+static inline void pmdp_set_wrprotect(struct mm_struct *mm,
+                                      unsigned long addr, pmd_t *pmdp)
+{
+        clear_bit(_PAGE_BIT_RW, (unsigned long *)pmdp);
+        pmd_update(mm, addr, pmdp);
+}
+
 /*
  * clone_pgd_range(pgd_t *dst, pgd_t *src, int count);
  *