X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=mm%2Fmprotect.c;h=638edabaff7118206b379c0436ffd6aa3e2fda40;hb=304c4c841a31c780a45d65e389b07706babf5d36;hp=57577f63b305e6a50fd0e9a2861dd2888a62dd77;hpb=c1d9728ecc5b560465df3c0c0d3b3825c2710b40;p=linux-2.6-omap-h63xx.git

diff --git a/mm/mprotect.c b/mm/mprotect.c
index 57577f63b30..638edabaff7 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>
@@ -28,11 +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(pmd, addr);
+	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
@@ -42,9 +45,24 @@ 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(pte - 1);
+	pte_unmap_unlock(pte - 1, ptl);
 }
 
 static inline void change_pmd_range(struct mm_struct *mm, pud_t *pud,
@@ -88,7 +106,6 @@ static void change_protection(struct vm_area_struct *vma,
 	BUG_ON(addr >= end);
 	pgd = pgd_offset(mm, addr);
 	flush_cache_range(vma, addr, end);
-	spin_lock(&mm->page_table_lock);
 	do {
 		next = pgd_addr_end(addr, end);
 		if (pgd_none_or_clear_bad(pgd))
@@ -96,7 +113,6 @@ static void change_protection(struct vm_area_struct *vma,
 		change_pud_range(mm, pgd, addr, next, newprot);
 	} while (pgd++, addr = next, addr != end);
 	flush_tlb_range(vma, start, end);
-	spin_unlock(&mm->page_table_lock);
 }
 
 static int
@@ -107,6 +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;
@@ -125,7 +142,7 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
 	 * a MAP_NORESERVE private mapping to writable will now reserve.
 	 */
 	if (newflags & VM_WRITE) {
-		if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_SHARED|VM_HUGETLB))) {
+		if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_SHARED))) {
 			charged = nrpages;
 			if (security_vm_enough_memory(charged))
 				return -ENOMEM;
@@ -133,8 +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.
 	 */
@@ -161,15 +176,26 @@ 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.
 	 */
 	vma->vm_flags = newflags;
 	vma->vm_page_prot = newprot;
-	change_protection(vma, start, end, newprot);
-	__vm_stat_account(mm, oldflags, vma->vm_file, -nrpages);
-	__vm_stat_account(mm, newflags, vma->vm_file, nrpages);
+	if (is_vm_hugetlb_page(vma))
+		hugetlb_change_protection(vma, start, end, newprot);
+	else
+		change_protection(vma, start, end, newprot);
+	vm_stat_account(mm, oldflags, vma->vm_file, -nrpages);
+	vm_stat_account(mm, newflags, vma->vm_file, nrpages);
 	return 0;
 
 fail:
@@ -203,8 +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);
@@ -241,11 +266,6 @@ sys_mprotect(unsigned long start, size_t len, unsigned long prot)
 
 		/* Here we know that  vma->vm_start <= nstart < vma->vm_end. */
 
-		if (is_vm_hugetlb_page(vma)) {
-			error = -EACCES;
-			goto out;
-		}
-
 		newflags = vm_flags | (vma->vm_flags & ~(VM_READ | VM_WRITE | VM_EXEC));
 
 		/* newflags >> 4 shift VM_MAY% in place of VM_% */