--- zzzz-none-000/linux-2.6.39.4/mm/memory.c	2011-08-03 19:43:28.000000000 +0000
+++ puma6-atom-6490-729/linux-2.6.39.4/mm/memory.c	2021-11-10 13:38:18.000000000 +0000
@@ -38,6 +38,13 @@
  * Aug/Sep 2004 Changed to four level page tables (Andi Kleen)
  */
 
+/******************************************************************
+ 
+ Includes Intel Corporation's changes/modifications dated: 01/2013.
+ Changed/modified portions - Copyright(c) 2013, Intel Corporation. 
+
+******************************************************************/
+
 #include <linux/kernel_stat.h>
 #include <linux/mm.h>
 #include <linux/hugetlb.h>
@@ -730,7 +737,7 @@
 		   pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
 		   unsigned long addr, unsigned long end)
 {
-	pte_t *orig_src_pte, *orig_dst_pte;
+	pte_t *orig_src_pte __attribute__((unused)), *orig_dst_pte __attribute__((unused));
 	pte_t *src_pte, *dst_pte;
 	spinlock_t *src_ptl, *dst_ptl;
 	int progress = 0;
@@ -1253,6 +1260,16 @@
 }
 EXPORT_SYMBOL_GPL(zap_vma_ptes);
 
+/*
+ * FOLL_FORCE can write to even unwritable pte's, but only
+ * after we've gone through a COW cycle and they are dirty.
+ */
+static inline bool can_follow_write_pte(pte_t pte, unsigned int flags)
+{
+	return pte_write(pte) ||
+		((flags & FOLL_FORCE) && (flags & FOLL_COW) && pte_dirty(pte));
+}
+
 /**
  * follow_page - look up a page descriptor from a user-virtual address
  * @vma: vm_area_struct mapping @address
@@ -1335,7 +1352,7 @@
 	pte = *ptep;
 	if (!pte_present(pte))
 		goto no_page;
-	if ((flags & FOLL_WRITE) && !pte_write(pte))
+	if ((flags & FOLL_WRITE) && !can_follow_write_pte(pte, flags))
 		goto unlock;
 
 	page = vm_normal_page(vma, address, pte);
@@ -1625,7 +1642,7 @@
 				 */
 				if ((ret & VM_FAULT_WRITE) &&
 				    !(vma->vm_flags & VM_WRITE))
-					foll_flags &= ~FOLL_WRITE;
+					foll_flags |= FOLL_COW;
 
 				cond_resched();
 			}
@@ -3657,6 +3674,9 @@
 
 	return len;
 }
+#ifdef CONFIG_ARCH_GEN3
+EXPORT_SYMBOL_GPL(generic_access_phys);
+#endif
 #endif
 
 /*