mm: remove blackfin MPU support

The CONFIG_MPU option was only defined on blackfin, and that architecture
is now being removed, so the respective code can be simplified.

A lot of other microcontrollers have an MPU, but I suspect that if we
want to bring that support back, we'd do it differently anyway.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

kernel/module.c

@@ -2181,10 +2181,6 @@ static void free_module(struct module *mod)
 	/* Finally, free the core (containing the module structure) */
 	disable_ro_nx(&mod->core_layout);
 	module_memfree(mod->core_layout.base);
-
-#ifdef CONFIG_MPU
-	update_protections(current->mm);
-#endif
 }
 
 void *__symbol_get(const char *symbol)

mm/nommu.c

@@ -662,22 +662,6 @@ static void put_nommu_region(struct vm_region *region)
 	__put_nommu_region(region);
 }
 
-/*
- * update protection on a vma
- */
-static void protect_vma(struct vm_area_struct *vma, unsigned long flags)
-{
-#ifdef CONFIG_MPU
-	struct mm_struct *mm = vma->vm_mm;
-	long start = vma->vm_start & PAGE_MASK;
-	while (start < vma->vm_end) {
-		protect_page(mm, start, flags);
-		start += PAGE_SIZE;
-	}
-	update_protections(mm);
-#endif
-}
-
 /*
  * add a VMA into a process's mm_struct in the appropriate place in the list
  * and tree and add to the address space's page tree also if not an anonymous
@@ -695,8 +679,6 @@ static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
 	mm->map_count++;
 	vma->vm_mm = mm;
 
-	protect_vma(vma, vma->vm_flags);
-
 	/* add the VMA to the mapping */
 	if (vma->vm_file) {
 		mapping = vma->vm_file->f_mapping;
@@ -757,8 +739,6 @@ static void delete_vma_from_mm(struct vm_area_struct *vma)
 	struct mm_struct *mm = vma->vm_mm;
 	struct task_struct *curr = current;
 
-	protect_vma(vma, 0);
-
 	mm->map_count--;
 	for (i = 0; i < VMACACHE_SIZE; i++) {
 		/* if the vma is cached, invalidate the entire cache */