[PATCH] Pass vma argument to copy_user_highpage().

To allow a more effective copy_user_highpage() on certain architectures,
a vma argument is added to the function and cow_user_page() allowing
the implementation of these functions to check for the VM_EXEC bit.

The main part of this patch was originally written by Ralf Baechle;
Atushi Nemoto did the the debugging.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

include/linux/highmem.h

@@ -98,7 +98,8 @@ static inline void memclear_highpage_flush(struct page *page, unsigned int offse
 
 #ifndef __HAVE_ARCH_COPY_USER_HIGHPAGE
 
-static inline void copy_user_highpage(struct page *to, struct page *from, unsigned long vaddr)
+static inline void copy_user_highpage(struct page *to, struct page *from,
+	unsigned long vaddr, struct vm_area_struct *vma)
 {
 	char *vfrom, *vto;
 

mm/hugetlb.c

@@ -44,14 +44,14 @@ static void clear_huge_page(struct page *page, unsigned long addr)
 }
 
 static void copy_huge_page(struct page *dst, struct page *src,
-			   unsigned long addr)
+			   unsigned long addr, struct vm_area_struct *vma)
 {
 	int i;
 
 	might_sleep();
 	for (i = 0; i < HPAGE_SIZE/PAGE_SIZE; i++) {
 		cond_resched();
-		copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE);
+		copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
 	}
 }
 
@@ -442,7 +442,7 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
 	}
 
 	spin_unlock(&mm->page_table_lock);
-	copy_huge_page(new_page, old_page, address);
+	copy_huge_page(new_page, old_page, address, vma);
 	spin_lock(&mm->page_table_lock);
 
 	ptep = huge_pte_offset(mm, address & HPAGE_MASK);

mm/memory.c

@@ -1441,7 +1441,7 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
 	return pte;
 }
 
-static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va)
+static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma)
 {
 	/*
 	 * If the source page was a PFN mapping, we don't have
@@ -1464,9 +1464,9 @@ static inline void cow_user_page(struct page *dst, struct page *src, unsigned lo
 		kunmap_atomic(kaddr, KM_USER0);
 		flush_dcache_page(dst);
 		return;
-		
+
 	}
-	copy_user_highpage(dst, src, va);
+	copy_user_highpage(dst, src, va, vma);
 }
 
 /*
@@ -1577,7 +1577,7 @@ gotten:
 		new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
 		if (!new_page)
 			goto oom;
-		cow_user_page(new_page, old_page, address);
+		cow_user_page(new_page, old_page, address, vma);
 	}
 
 	/*
@@ -2200,7 +2200,7 @@ retry:
 			page = alloc_page_vma(GFP_HIGHUSER, vma, address);
 			if (!page)
 				goto oom;
-			copy_user_highpage(page, new_page, address);
+			copy_user_highpage(page, new_page, address, vma);
 			page_cache_release(new_page);
 			new_page = page;
 			anon = 1;