mpfs_mpu: Check that size is valid for MPUCFG

The size must be power-of-two for NAPOT according to the the PMP spec.

Signed-off-by: Jani Paalijarvi <[email protected]>

arch/risc-v/src/mpfs/mpfs_mpu.c

@@ -159,9 +159,11 @@ int mpfs_mpu_set(uintptr_t reg, uintptr_t perm, uintptr_t base,
       return -EACCES;
     }
 
-  /* Base must be word aligned, minimum size is 4K */
+  /* Base must be word aligned,
+   * minimum size is 4K and it has to be power-of-two
+   */
 
-  if ((base & 0x07) != 0 || size < 0x1000)
+  if ((base & 0x07) != 0 || size < 0x1000 || (size & (size - 1)) != 0)
     {
       return -EINVAL;
     }