static inline void cr4_toggle_bits_irqsoff(unsigned long mask)
{
	unsigned long newval, cr4 = this_cpu_read(cpu_tlbstate.cr4);

	newval = cr4 ^ mask;
	if (newval != cr4) {
		this_cpu_write(cpu_tlbstate.cr4, newval);
		__write_cr4(newval);
	}
}
Unknown