bb4f757ba0
Implement CPU power-saving idle loop using x86 MONITOR/MWAIT: - Add monitor(), mwait(), enable_and_mwait() to interrupt module - Detect MWAIT availability via CPUID at boot - Use MONITOR+MWAIT instead of STI+HLT when supported - Expose /scheme/sys/cstate_policy for userspace control - Add RdWr Kind variant to sys scheme for read+write files