diff options
Diffstat (limited to 'mm/tlb.cc')
| -rw-r--r-- | mm/tlb.cc | 90 |
1 files changed, 0 insertions, 90 deletions
diff --git a/mm/tlb.cc b/mm/tlb.cc deleted file mode 100644 index b7a8ba7..0000000 --- a/mm/tlb.cc +++ /dev/null @@ -1,90 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-or-later */ -/* Copyright (C) 2026 Richard Qin */ - -/* - * tlb.cc — TLB shootdown implementation - * - * Uses RISC-V SBI Remote Fence extension to perform cross-hart - * TLB invalidation. SBI firmware handles the IPI delivery and - * synchronization — the call blocks until all target harts have - * completed their local sfence.vma. - * - * When a VmSpace is provided, we use its cpu_mask to target only - * the CPUs that have this address space loaded in satp. This avoids - * unnecessary IPI storms on unrelated cores. - * - * Reference: docs/specs/linux_abi_mm_plan.md §SMP §2.1 - */ - -#include <lume/tlb.h> -#include <lume/vmm.h> -#include <lume/config.h> -#include <arch/mmu.h> -#include <arch/tlb.h> -#include <arch/cpu.h> - -/* - * If a shootdown range exceeds this many pages, do a full flush - * instead of per-page invalidation. - */ -static constexpr uint64 kShootdownPageThreshold = 32; - -/* - * Build a cpu mask for all online CPUs (fallback when mm is null). - */ -namespace { -uint64 all_cpus_mask() -{ - uint64 mask = 0; - for (uint32 i = 0; i < kMaxCpus; i++) { - mask |= (1ULL << i); - } - return mask; -} - -/* - * Get the target cpu mask: use mm->cpu_mask when available, - * fall back to all_cpus_mask for kernel address space (mm == nullptr). - */ -uint64 target_cpu_mask(VmSpace* mm) -{ - if (mm) { - uint64 mask = mm->cpu_mask.load(__ATOMIC_RELAXED); - /* Always include our own CPU — we may still have stale TLB */ - mask |= (1ULL << arch::cpu::id()); - return mask; - } - return all_cpus_mask(); -} -} // namespace - -void tlb_shootdown_range(VmSpace* mm, uint64 start, uint64 end) -{ - if (start >= end) { - return; - } - - uint64 num_pages = (end - start) / kPageSize; - uint64 cpu_mask = target_cpu_mask(mm); - - if (num_pages > kShootdownPageThreshold) { - /* Full flush on target CPUs via arch backend */ - arch::tlb::flush_remote(cpu_mask, 0, ~0ULL); - return; - } - - /* Range flush on target CPUs via arch backend */ - arch::tlb::flush_remote(cpu_mask, start, end - start); -} - -void tlb_shootdown_page(VmSpace* mm, uint64 va) -{ - uint64 cpu_mask = target_cpu_mask(mm); - arch::tlb::flush_remote(cpu_mask, va, kPageSize); -} - -void tlb_shootdown_all() -{ - uint64 cpu_mask = all_cpus_mask(); - arch::tlb::flush_remote(cpu_mask, 0, ~0ULL); -} |
