X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=mm%2Fmprotect.c;h=638edabaff7118206b379c0436ffd6aa3e2fda40;hb=d7fa2589bbe7ab53fd5eb20e8c7e388d5aff6f16;hp=4c14d4289b61a69406140bfa9d0e1cf5919d99c7;hpb=2e9abdd9bad485970b37cd53a82f92702054984c;p=pandora-kernel.git

diff --git a/mm/mprotect.c b/mm/mprotect.c
index 4c14d4289b61..638edabaff71 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -19,7 +19,8 @@
 #include <linux/mempolicy.h>
 #include <linux/personality.h>
 #include <linux/syscalls.h>
-
+#include <linux/swap.h>
+#include <linux/swapops.h>
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
 #include <asm/cacheflush.h>
@@ -28,12 +29,13 @@
 static void change_pte_range(struct mm_struct *mm, pmd_t *pmd,
 		unsigned long addr, unsigned long end, pgprot_t newprot)
 {
-	pte_t *pte;
+	pte_t *pte, oldpte;
 	spinlock_t *ptl;
 
 	pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
 	do {
-		if (pte_present(*pte)) {
+		oldpte = *pte;
+		if (pte_present(oldpte)) {
 			pte_t ptent;
 
 			/* Avoid an SMP race with hardware updated dirty/clean
@@ -43,7 +45,22 @@ static void change_pte_range(struct mm_struct *mm, pmd_t *pmd,
 			ptent = pte_modify(ptep_get_and_clear(mm, addr, pte), newprot);
 			set_pte_at(mm, addr, pte, ptent);
 			lazy_mmu_prot_update(ptent);
+#ifdef CONFIG_MIGRATION
+		} else if (!pte_file(oldpte)) {
+			swp_entry_t entry = pte_to_swp_entry(oldpte);
+
+			if (is_write_migration_entry(entry)) {
+				/*
+				 * A protection check is difficult so
+				 * just be safe and disable write
+				 */
+				make_migration_entry_read(&entry);
+				set_pte_at(mm, addr, pte,
+					swp_entry_to_pte(entry));
+			}
+#endif
 		}
+
 	} while (pte++, addr += PAGE_SIZE, addr != end);
 	pte_unmap_unlock(pte - 1, ptl);
 }
@@ -106,6 +123,7 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
 	unsigned long oldflags = vma->vm_flags;
 	long nrpages = (end - start) >> PAGE_SHIFT;
 	unsigned long charged = 0;
+	unsigned int mask;
 	pgprot_t newprot;
 	pgoff_t pgoff;
 	int error;
@@ -132,8 +150,6 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
 		}
 	}
 
-	newprot = protection_map[newflags & 0xf];
-
 	/*
 	 * First try to merge with previous and/or next vma.
 	 */
@@ -160,6 +176,14 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
 	}
 
 success:
+	/* Don't make the VMA automatically writable if it's shared, but the
+	 * backer wishes to know when pages are first written to */
+	mask = VM_READ|VM_WRITE|VM_EXEC|VM_SHARED;
+	if (vma->vm_ops && vma->vm_ops->page_mkwrite)
+		mask &= ~VM_SHARED;
+
+	newprot = protection_map[newflags & mask];
+
 	/*
 	 * vm_flags and vm_page_prot are protected by the mmap_sem
 	 * held in write mode.
@@ -205,8 +229,7 @@ sys_mprotect(unsigned long start, size_t len, unsigned long prot)
 	/*
 	 * Does the application expect PROT_READ to imply PROT_EXEC:
 	 */
-	if (unlikely((prot & PROT_READ) &&
-			(current->personality & READ_IMPLIES_EXEC)))
+	if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
 		prot |= PROT_EXEC;
 
 	vm_flags = calc_vm_prot_bits(prot);