As seen in FreeBSD ASLR, we can open things up on 64-bit platforms.
effects:
alpha: limit to 1GB (maxdsiz/brksiz)
amd64 and sparc64: limit to 4gb (8gb maxdsiz)
Index: uvm_map.c
===================================================================
RCS file: /cvs/src/sys/uvm/uvm_map.c,v
retrieving revision 1.170
diff -u -p -r1.170 uvm_map.c
--- uvm_map.c 11 Jul 2014 16:35:40 -0000 1.170
+++ uvm_map.c 12 Jul 2014 07:56:15 -0000
@@ -3541,7 +3541,11 @@ uvm_map_hint(struct vmspace *vm, vm_prot
}
#endif
+#ifdef __LP64__
+ spacing = (MIN((4UL * 1024 * 1024 * 1024), BRKSIZ) - 1);
+#else
spacing = (MIN((256 * 1024 * 1024), BRKSIZ) - 1);
+#endif
addr = (vaddr_t)vm->vm_daddr;
/*
