cpuid value is not correct on intel HSW cpu

platform: sharkbay platform with haswell cpu
symptom: the eax, ebx, ecx ,edx values with cpuid eax=7 are all zero, this isn't correct on haswell cpu.

reason : Before cpuid app executes cpuid instruction, it doesn't clear ebx, ecx and edx, this break intel cpuid instruction rule.
                 you can check cpuid instruction at : http://download.intel.com/products/processor/manual/325383.pdf