cpu - Intel Atom D2500, 64-bit mode

I have an Intel Atom D2500 processor which the spec site claims it supports a 64-bit instruction set. However, cpuinfo shows this:

# cat /proc/cpuinfo | egrep "(processor|flags|address)"
processor       : 0
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36  clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx constant_tsc arch_perfmon pebs bts  nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl tm2 ssse3 xtpr pdcm movbe lahf_lm arat
address sizes   : 36 bits physical, 32 bits virtual
processor       : 1
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36  clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx constant_tsc arch_perfmon pebs bts  nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl tm2 ssse3 xtpr pdcm movbe lahf_lm arat
address sizes   : 36 bits physical, 32 bits virtual

Does anyone know any way to enable the lm flag in the processor? So I can use a 64-bit kernel?