I ran into two problems with boot_cpu_data:

- boot_cpu_data doesn't contain the common capabilities of all cpus, it 
contains the capabilities of the last booted cpu:
head.S is called by the trampoline code, and that overwrites 
boot_cpu_data. [Untested due to lack of hardware]

- "mem=nopentium" disables the pse bit, but that is lost when 
identify_cpu calls cpuid again.

What about the attached patch?
it creates an __initdata structure for head.S and adds a flag that 
informs identify_cpu that pse is disabled.

--
    Manfred