VBoot Reference: Add version checking to for preventing rollbacks.

src/platform/vboot_reference/include/utility.h

 /* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /* Helper functions/wrappers for memory allocations, manipulation and
  * comparison.
  */
 
 #ifndef VBOOT_REFERENCE_UTILITY_H_
 #define VBOOT_REFERENCE_UTILITY_H_
 
 #include <inttypes.h>
 #include <string.h>
 
+/* Combine [msw] and [lsw] uint16s to a uint32_t with its [msw] and
+ * [lsw] forming the most and least signficant 16-bit words.
+ */
+#define CombineUint16Pair(msw,lsw) (((msw) << 16) |     \
+                                    (((lsw)) & 0xFFFF))
+/* Return the minimum of (a) or (b). */
+#define Min(a, b) (((a) < (b)) ? (a) : (b))
+
 /* Allocate [size] bytes and return a pointer to the allocated memory. Abort
  * on error.
  */
 void* Malloc(size_t size);
 
 /* Free memory pointed by [ptr] previously allocated by Malloc(). */
 void Free(void* ptr);
 
 /* Copy [n] bytes from [src] to [dest]. */
 void* Memcpy(void* dest, const void* src, size_t n);
@@ skipping 27 matching lines @@
  * data from [src] into the buffer encapsulated in state [state].
  * On success, return [src] and update [state].
  * On failure, return NULL, set remaining_len in state to -1.
  *
  * Useful for iterating through a structure to populate a binary blob. After the
  * first failure (buffer overrun), successive calls will always fail.
  */
 const void* StatefulMemcpy_r(MemcpyState* state, const void* src, int len);
 
 #endif  /* VBOOT_REFERENCE_UTILITY_H_ */