get_unmapped_area handles MAP_FIXED on x86_64

Handle MAP_FIXED in x86_64 arch_get_unmapped_area(), simple case, just return
the address as passed in

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/x86_64/kernel/sys_x86_64.c

@@ -93,6 +93,9 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
 	unsigned long start_addr;
 	unsigned long begin, end;
 
+	if (flags & MAP_FIXED)
+		return addr;
+
 	find_start_end(flags, &begin, &end); 
 
 	if (len > end)