Module tlb 

TLB (Translation Lookaside Buffer) shootdown for SMP.

When a page table entry is modified on one CPU, all other CPUs that might have cached that entry in their TLB must be notified to invalidate it.

This implementation uses a per-CPU mailbox system inspired by Asterinas:

1. Each CPU has its own queue of pending TLB operations.
2. The initiator pushes an operation into each target’s queue.
3. The initiator sends a TLB shootdown IPI to all targets.
4. The targets process their own queue and set an ACK flag.
5. The initiator waits for all ACK flags to become true.

This avoids global lock contention and race conditions on global counters.

Functions

init

Initialize TLB shootdown system.

shootdown_all

Flush all TLB entries on all CPUs.

shootdown_page

Invalidate a single page on all CPUs.

shootdown_range

Invalidate a range of pages on all CPUs.

tlb_shootdown_ipi_handler

IPI handler for TLB shootdown (called on receiving CPU).