/* asm-generic/tlb.h * * Generic TLB shootdown code * * Copyright 2001 Red Hat, Inc. * Based on code from mm/memory.c Copyright Linus Torvalds and others. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #ifndef _ASM_GENERIC__TLB_H #define _ASM_GENERIC__TLB_H #include <linux/swap.h> #include <asm/pgalloc.h> #include <asm/tlbflush.h> /* * For UP we don't need to worry about TLB flush * and page free order so much.. */ #ifdef CONFIG_SMP #ifdef ARCH_FREE_PTR_NR #define FREE_PTR_NR ARCH_FREE_PTR_NR #else #define FREE_PTE_NR 506 #endif #define tlb_fast_mode(tlb) ((tlb)->nr == ~0U) #else #define FREE_PTE_NR 1 #define tlb_fast_mode(tlb) 1 #endif /* struct mmu_gather is an opaque type used by the mm code for passing around * any data needed by arch specific code for tlb_remove_page. */ struct mmu_gather { struct mm_struct *mm; unsigned int nr; /* set to ~0U means fast mode */ unsigned int need_flush;/* Really unmapped some ptes? */ unsigned int fullmm; /* non-zero means full mm flush */ struct page * pages[FREE_PTE_NR]; }; /* Users of the generic TLB shootdown code must declare this storage space. */ DECLARE_PER_CPU(struct mmu_gather, mmu_gathers); /* tlb_gather_mmu * Return a pointer to an initialized struct mmu_gather. */ static inline struct mmu_gather * tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush) { struct mmu_gather *tlb = &get_cpu_var(mmu_gathers); tlb->mm = mm; /* Use fast mode if only one CPU is online */ tlb->nr = num_online_cpus() > 1 ? 0U : ~0U; tlb->fullmm = full_mm_flush; return tlb; } static inline void tlb_flush_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end) { if (!tlb->need_flush) return; tlb->need_flush = 0; tlb_flush(tlb); if (!tlb_fast_mode(tlb)) { free_pages_and_swap_cache(tlb->pages, tlb->nr); tlb->nr = 0; } } /* tlb_finish_mmu * Called at the end of the shootdown operation to free up any resources * that were required. */ static inline void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end) { tlb_flush_mmu(tlb, start, end); /* keep the page table cache within bounds */ check_pgt_cache(); put_cpu_var(mmu_gathers); } /* tlb_remove_page * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while * handling the additional races in SMP caused by other CPUs caching valid * mappings in their TLBs. */ static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page) { tlb->need_flush = 1; if (tlb_fast_mode(tlb)) { free_page_and_swap_cache(page); return; } tlb->pages[tlb->nr++] = page; if (tlb->nr >= FREE_PTE_NR) tlb_flush_mmu(tlb, 0, 0); } /** * tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation. * * Record the fact that pte's were really umapped in ->need_flush, so we can * later optimise away the tlb invalidate. This helps when userspace is * unmapping already-unmapped pages, which happens quite a lot. */ #define tlb_remove_tlb_entry(tlb, ptep, address) \ do { \ tlb->need_flush = 1; \ __tlb_remove_tlb_entry(tlb, ptep, address); \ } while (0) #define pte_free_tlb(tlb, ptep) \ do { \ tlb->need_flush = 1; \ __pte_free_tlb(tlb, ptep); \ } while (0) #ifndef __ARCH_HAS_4LEVEL_HACK #define pud_free_tlb(tlb, pudp) \ do { \ tlb->need_flush = 1; \ __pud_free_tlb(tlb, pudp); \ } while (0) #endif #define pmd_free_tlb(tlb, pmdp) \ do { \ tlb->need_flush = 1; \ __pmd_free_tlb(tlb, pmdp); \ } while (0) #define tlb_migrate_finish(mm) do {} while (0) #endif /* _ASM_GENERIC__TLB_H */