mm/map: revise device mapping functions

This revises vm_map_region() by accepting unaligned paddr, which is
aligned-down before mapping and in-page offset is then added to vaddr
before returning. It also moves vm_map_region() and vm_unmap_region()
to vm_region.c.

Signed-off-by: Yanfeng Liu <yfliu2008@qq.com>

include/nuttx/mm/map.h

@@ -200,7 +200,10 @@ void vm_release_region(FAR struct mm_map_s *mm, FAR void *vaddr,
  *
  * Description:
  *   Allocate virtual memory and maps given physical memory into user space
- *   of the current process.
+ *   of the current process. The mapped region can be larger than requested
+ *   if given paddr isn't page-aligned, use with care so that not to create
+ *   unwanted security holes. The returned virtual address has same in-page
+ *   alignment as given paddr.
  *
  * Input Parameters:
  *   paddr - Starting physical address

mm/map/vm_map.c

@@ -1,91 +0,0 @@
-/****************************************************************************
- * mm/map/vm_map.c
- *
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.  The
- * ASF licenses this file to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance with the
- * License.  You may obtain a copy of the License at
- *
- *   http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
- * License for the specific language governing permissions and limitations
- * under the License.
- *
- ****************************************************************************/
-
-/****************************************************************************
- * Included Files
- ****************************************************************************/
-
-#include <debug.h>
-
-#include <nuttx/arch.h>
-#include <nuttx/mm/map.h>
-#include <nuttx/pgalloc.h>
-#include <nuttx/sched.h>
-
-/****************************************************************************
- * Public Functions
- ****************************************************************************/
-
-#ifdef CONFIG_ARCH_VMA_MAPPING
-
-/* map physical region to userspace */
-
-FAR void *vm_map_region(uintptr_t paddr, size_t size)
-{
-  FAR void *vaddr;
-  uintptr_t tvaddr;
-  uint      i      = 0;
-  int       ret    = OK;
-  size_t    npages = MM_NPAGES(size);
-
-  DEBUGASSERT(npages > 0);
-  DEBUGASSERT(MM_ISALIGNED(paddr));
-
-  vaddr = vm_alloc_region(get_current_mm(), 0, size);
-  if (vaddr)
-    {
-      tvaddr = (uintptr_t)vaddr;
-      for (; i < npages; i++, tvaddr += MM_PGSIZE, paddr += MM_PGSIZE)
-        {
-          ret = up_shmat(&paddr, 1, tvaddr);
-          if (ret)
-            {
-              goto errorout;
-            }
-        }
-    }
-
-  return vaddr;
-
-errorout:
-  if (i)   /* undo mapped pages */
-    {
-      up_shmdt((uintptr_t)vaddr, i);
-    }
-
-  vm_release_region(get_current_mm(), vaddr, size);
-  return 0;
-}
-
-/* unmap userspace device pointer */
-
-int vm_unmap_region(FAR void *vaddr, size_t size)
-{
-  size_t npages = MM_NPAGES(size);
-  int ret;
-
-  DEBUGASSERT(MM_ISALIGNED(vaddr));
-  DEBUGASSERT(npages);
-  ret = up_shmdt((uintptr_t)vaddr, npages);
-  vm_release_region(get_current_mm(), vaddr, size);
-  return ret;
-}
-
-#endif /* CONFIG_ARCH_VMA_MAPPING */

mm/map/vm_region.c

@@ -22,8 +22,10 @@
  * Included Files
  ****************************************************************************/
 
+#include <nuttx/arch.h>
 #include <nuttx/mm/map.h>
 #include <nuttx/mm/gran.h>
+#include <nuttx/pgalloc.h>
 #include <debug.h>
 
 /****************************************************************************
@@ -91,3 +93,60 @@ void vm_release_region(FAR struct mm_map_s *mm, FAR void *vaddr, size_t size)
       gran_free(mm->mm_map_vpages, vaddr, size);
     }
 }
+
+/* map physical region to userspace */
+
+FAR void *vm_map_region(uintptr_t paddr, size_t size)
+{
+  FAR void *vaddr;
+  uintptr_t tvaddr;
+  size_t    npages;
+  uintptr_t tpaddr = MM_PGALIGNDOWN(paddr);
+  uint      i      = 0;
+  int       ret    = OK;
+
+  DEBUGASSERT(paddr);
+
+  size += (paddr & MM_PGMASK);
+  npages = MM_NPAGES(size);
+  DEBUGASSERT(npages);
+
+  vaddr = vm_alloc_region(get_current_mm(), 0, size);
+  if (vaddr)
+    {
+      tvaddr = (uintptr_t)vaddr;
+      for (; i < npages; i++, tvaddr += MM_PGSIZE, tpaddr += MM_PGSIZE)
+        {
+          ret = up_shmat(&tpaddr, 1, tvaddr);
+          if (ret)
+            {
+              goto error;
+            }
+        }
+    }
+
+  return vaddr + (MM_PGMASK & paddr);
+
+error:
+  if (i)   /* undo alway mapped pages */
+    {
+      up_shmdt((uintptr_t)vaddr, i);
+    }
+
+  vm_release_region(get_current_mm(), vaddr, size);
+  return 0;
+}
+
+/* unmap userspace device pointer */
+
+int vm_unmap_region(FAR void *vaddr, size_t size)
+{
+  int ret;
+
+  DEBUGASSERT(size && vaddr);
+  size += ((uintptr_t)vaddr & MM_PGMASK);
+  vaddr = (void *)MM_PGALIGNDOWN(vaddr);
+  ret = up_shmdt((uintptr_t)vaddr, MM_NPAGES(size));
+  vm_release_region(get_current_mm(), vaddr, size);
+  return ret;
+}