Changed BRK_END to 0x0000300000000000 (XCC)

Allows mmaps in the high EPT address space

Change-Id: I8f19f755708a8de455582a14964fb17d2751dc62
Signed-off-by: Zach Zimmerman <zpzimmerman@gmail.com>
[ XCC warning - rebuild glibc if you're paranoid ]
Signed-off-by: Barret Rhoden <brho@cs.berkeley.edu>

kern/arch/x86/ros/mmu64.h

diff --git a/kern/arch/x86/ros/mmu64.h b/kern/arch/x86/ros/mmu64.h
index 28649ad..7ed3b88 100644
--- a/kern/arch/x86/ros/mmu64.h
+++ b/kern/arch/x86/ros/mmu64.h
@@ -111,7 +111,7 @@
  *                     |                              |
  *                     .                              .
  *                     .                              .
- *    BRK_END   ---->  +------------------------------+ 0x0000400000000000
+ *    BRK_END   ---->  +------------------------------+ 0x0000300000000000
  *                     .                              .
  *                     .                              .
  *                     |                              |
@@ -202,7 +202,7 @@
 #define UVPT			(ULIM - PML4_PTE_REACH)
 /* Arbitrary boundary between the break and the start of
  * memory returned by calls to mmap with addr = 0 */
-#define BRK_END			0x0000400000000000
+#define BRK_END			0x0000300000000000
 /* Arbitrary boundary where the break (glibc's heap) starts.  You can safely
  * mmap with MAP_FIXED below this address. */
 #define BRK_START		0x0000100000000000