of: Add OF_DMA_DEFAULT_COHERENT & select it on powerpc

[sagit-ice-cold/kernel_xiaomi_msm8998.git] / mm / mprotect.c

diff --git a/mm/mprotect.c b/mm/mprotect.c
index ef5be8e..a277f34 100644 (file)
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -72,6 +72,7 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
        if (!pte)
                return 0;
 
+       flush_tlb_batched_pending(vma->vm_mm);
        arch_enter_lazy_mmu_mode();
        do {
                oldpte = *pte;
@@ -254,6 +255,42 @@ unsigned long change_protection(struct vm_area_struct *vma, unsigned long start,
        return pages;
 }
 
+static int prot_none_pte_entry(pte_t *pte, unsigned long addr,
+                              unsigned long next, struct mm_walk *walk)
+{
+       return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ?
+               0 : -EACCES;
+}
+
+static int prot_none_hugetlb_entry(pte_t *pte, unsigned long hmask,
+                                  unsigned long addr, unsigned long next,
+                                  struct mm_walk *walk)
+{
+       return pfn_modify_allowed(pte_pfn(*pte), *(pgprot_t *)(walk->private)) ?
+               0 : -EACCES;
+}
+
+static int prot_none_test(unsigned long addr, unsigned long next,
+                         struct mm_walk *walk)
+{
+       return 0;
+}
+
+static int prot_none_walk(struct vm_area_struct *vma, unsigned long start,
+                          unsigned long end, unsigned long newflags)
+{
+       pgprot_t new_pgprot = vm_get_page_prot(newflags);
+       struct mm_walk prot_none_walk = {
+               .pte_entry = prot_none_pte_entry,
+               .hugetlb_entry = prot_none_hugetlb_entry,
+               .test_walk = prot_none_test,
+               .mm = current->mm,
+               .private = &new_pgprot,
+       };
+
+       return walk_page_range(start, end, &prot_none_walk);
+}
+
 int
 mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
        unsigned long start, unsigned long end, unsigned long newflags)
@@ -272,6 +309,19 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
        }
 
        /*
+        * Do PROT_NONE PFN permission checks here when we can still
+        * bail out without undoing a lot of state. This is a rather
+        * uncommon case, so doesn't need to be very optimized.
+        */
+       if (arch_has_pfn_modify_check() &&
+           (vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) &&
+           (newflags & (VM_READ|VM_WRITE|VM_EXEC)) == 0) {
+               error = prot_none_walk(vma, start, end, newflags);
+               if (error)
+                       return error;
+       }
+
+       /*
         * If we make a private mapping writable we increase our commit;
         * but (without finer accounting) cannot reduce our commit if we
         * make it unwritable again. hugetlb mapping were accounted for