3 files changed, 54 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/book3s/64/hugetlb.h b/arch/powerpc/include/asm/book3s/64/hugetlb.h
index 5b0177733994..66c1e4f88d65 100644
--- a/arch/powerpc/include/asm/book3s/64/hugetlb.h
+++ b/arch/powerpc/include/asm/book3s/64/hugetlb.h
@@ -13,6 +13,10 @@ radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
                                 unsigned long len, unsigned long pgoff,
                                 unsigned long flags);
 
+extern void radix__huge_ptep_modify_prot_commit(struct vm_area_struct *vma,
+                                                unsigned long addr, pte_t *ptep,
+                                                pte_t old_pte, pte_t pte);
+
 static inline int hstate_get_psize(struct hstate *hstate)
 {
         unsigned long shift;
@@ -42,4 +46,12 @@ static inline bool gigantic_page_supported(void)
 /* hugepd entry valid bit */
 #define HUGEPD_VAL_BITS         (0x8000000000000000UL)
 
+#define huge_ptep_modify_prot_start huge_ptep_modify_prot_start
+extern pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma,
+                                         unsigned long addr, pte_t *ptep);
+
+#define huge_ptep_modify_prot_commit huge_ptep_modify_prot_commit
+extern void huge_ptep_modify_prot_commit(struct vm_area_struct *vma,
+                                         unsigned long addr, pte_t *ptep,
+                                         pte_t old_pte, pte_t new_pte);
 #endif
diff --git a/arch/powerpc/mm/hugetlbpage-hash64.c b/arch/powerpc/mm/hugetlbpage-hash64.c
index 2e6a8f9345d3..367ce3a4a503 100644
--- a/arch/powerpc/mm/hugetlbpage-hash64.c
+++ b/arch/powerpc/mm/hugetlbpage-hash64.c
@@ -121,3 +121,28 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
         *ptep = __pte(new_pte & ~H_PAGE_BUSY);
         return 0;
 }
+
+pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma,
+                                  unsigned long addr, pte_t *ptep)
+{
+        unsigned long pte_val;
+        /*
+         * Clear the _PAGE_PRESENT so that no hardware parallel update is
+         * possible. Also keep the pte_present true so that we don't take
+         * wrong fault.
+         */
+        pte_val = pte_update(vma->vm_mm, addr, ptep,
+                             _PAGE_PRESENT, _PAGE_INVALID, 1);
+
+        return __pte(pte_val);
+}
+
+void huge_ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr,
+                                  pte_t *ptep, pte_t old_pte, pte_t pte)
+{
+
+        if (radix_enabled())
+                return radix__huge_ptep_modify_prot_commit(vma, addr, ptep,
+                                                           old_pte, pte);
+        set_huge_pte_at(vma->vm_mm, addr, ptep, pte);
+}
diff --git a/arch/powerpc/mm/hugetlbpage-radix.c b/arch/powerpc/mm/hugetlbpage-radix.c
index 2486bee0f93e..11d9ea28a816 100644
--- a/arch/powerpc/mm/hugetlbpage-radix.c
+++ b/arch/powerpc/mm/hugetlbpage-radix.c
@@ -90,3 +90,20 @@ radix__hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 
         return vm_unmapped_area(&info);
 }
+
+void radix__huge_ptep_modify_prot_commit(struct vm_area_struct *vma,
+                                         unsigned long addr, pte_t *ptep,
+                                         pte_t old_pte, pte_t pte)
+{
+        struct mm_struct *mm = vma->vm_mm;
+
+        /*
+         * To avoid NMMU hang while relaxing access we need to flush the tlb before
+         * we set the new value.
+         */
+        if (is_pte_rw_upgrade(pte_val(old_pte), pte_val(pte)) &&
+            (atomic_read(&mm->context.copros) > 0))
+                radix__flush_hugetlb_page(vma, addr);
+
+        set_huge_pte_at(vma->vm_mm, addr, ptep, pte);
+}