/* 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 voidtlb_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 voidtlb_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 */