arch/powerpc/mm: Nest MMU workaround for mprotect RW upgrade

[linux-2.6-block.git] / arch / powerpc / mm / pgtable-book3s64.c

diff --git a/arch/powerpc/mm/pgtable-book3s64.c b/arch/powerpc/mm/pgtable-book3s64.c
index f3c31f5e1026fca9f2e01da261e1319dccbceaf0..e7da590c7a786f5325f17f7e1abc6cb112bebf80 100644 (file)
--- a/arch/powerpc/mm/pgtable-book3s64.c
+++ b/arch/powerpc/mm/pgtable-book3s64.c
@@ -400,3 +400,50 @@ void arch_report_meminfo(struct seq_file *m)
                   atomic_long_read(&direct_pages_count[MMU_PAGE_1G]) << 20);
 }
 #endif /* CONFIG_PROC_FS */
+
+pte_t 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, 0);
+
+       return __pte(pte_val);
+
+}
+
+void 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__ptep_modify_prot_commit(vma, addr,
+                                                     ptep, old_pte, pte);
+       set_pte_at(vma->vm_mm, addr, ptep, pte);
+}
+
+/*
+ * For hash translation mode, we use the deposited table to store hash slot
+ * information and they are stored at PTRS_PER_PMD offset from related pmd
+ * location. Hence a pmd move requires deposit and withdraw.
+ *
+ * For radix translation with split pmd ptl, we store the deposited table in the
+ * pmd page. Hence if we have different pmd page we need to withdraw during pmd
+ * move.
+ *
+ * With hash we use deposited table always irrespective of anon or not.
+ * With radix we use deposited table only for anonymous mapping.
+ */
+int pmd_move_must_withdraw(struct spinlock *new_pmd_ptl,
+                          struct spinlock *old_pmd_ptl,
+                          struct vm_area_struct *vma)
+{
+       if (radix_enabled())
+               return (new_pmd_ptl != old_pmd_ptl) && vma_is_anonymous(vma);
+
+       return true;
+}