/* * arch/arm/include/asm/tlb.h * * Copyright (C) 2002 Russell King * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * * Experimentation shows that on a StrongARM, it appears to be faster * to use the "invalidate whole tlb" rather than "invalidate single * tlb" for this. * * This appears true for both the process fork+exit case, as well as * the munmap-large-area case. */ #ifndef __ASMARM_TLB_H #define __ASMARM_TLB_H #include <asm/cacheflush.h> #ifndef CONFIG_MMU #include <linux/pagemap.h> #define tlb_flush(tlb) ((void) tlb) #include <asm-generic/tlb.h> #else /* !CONFIG_MMU */ #include <linux/swap.h> #include <asm/pgalloc.h> #include <asm/tlbflush.h> #define MMU_GATHER_BUNDLE 8 /* * TLB handling. This allows us to remove pages from the page * tables, and efficiently handle the TLB issues. */ struct mmu_gather { struct mm_struct *mm; unsigned int fullmm; struct vm_area_struct *vma; unsigned long start, end; unsigned long range_start; unsigned long range_end; unsigned int nr; unsigned int max; struct page **pages; struct page *local[MMU_GATHER_BUNDLE]; }; DECLARE_PER_CPU(struct mmu_gather, mmu_gathers); /* * This is unnecessarily complex. There's three ways the TLB shootdown * code is used: * 1. Unmapping a range of vmas. See zap_page_range(), unmap_region(). * tlb->fullmm = 0, and tlb_start_vma/tlb_end_vma will be called. * tlb->vma will be non-NULL. * 2. Unmapping all vmas. See exit_mmap(). * tlb->fullmm = 1, and tlb_start_vma/tlb_end_vma will be called. * tlb->vma will be non-NULL. Additionally, page tables will be freed. * 3. Unmapping argument pages. See shift_arg_pages(). * tlb->fullmm = 0, but tlb_start_vma/tlb_end_vma will not be called. * tlb->vma will be NULL. */ static inline void tlb_flush(struct mmu_gather *tlb) { if (tlb->fullmm || !tlb->vma) flush_tlb_mm(tlb->mm); else if (tlb->range_end > 0) { flush_tlb_range(tlb->vma, tlb->range_start, tlb->range_end); tlb->range_start = TASK_SIZE; tlb->range_end = 0; } } static inline void tlb_add_flush(struct mmu_gather *tlb, unsigned long addr) { if (!tlb->fullmm) { if (addr < tlb->range_start) tlb->range_start = addr; if (addr + PAGE_SIZE > tlb->range_end) tlb->range_end = addr + PAGE_SIZE; } } static inline void __tlb_alloc_page(struct mmu_gather *tlb) { unsigned long addr = __get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0); if (addr) { tlb->pages = (void *)addr; tlb->max = PAGE_SIZE / sizeof(struct page *); } } static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb) { tlb_flush(tlb); } static inline void tlb_flush_mmu_free(struct mmu_gather *tlb) { free_pages_and_swap_cache(tlb->pages, tlb->nr); tlb->nr = 0; if (tlb->pages == tlb->local) __tlb_alloc_page(tlb); } static inline void tlb_flush_mmu(struct mmu_gather *tlb) { tlb_flush_mmu_tlbonly(tlb); tlb_flush_mmu_free(tlb); } static inline void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end) { tlb->mm = mm; tlb->fullmm = !(start | (end+1)); tlb->start = start; tlb->end = end; tlb->vma = NULL; tlb->max = ARRAY_SIZE(tlb->local); tlb->pages = tlb->local; tlb->nr = 0; __tlb_alloc_page(tlb); } static inline void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end) { tlb_flush_mmu(tlb); /* keep the page table cache within bounds */ check_pgt_cache(); if (tlb->pages != tlb->local) free_pages((unsigned long)tlb->pages, 0); } /* * Memorize the range for the TLB flush. */ static inline void tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep, unsigned long addr) { tlb_add_flush(tlb, addr); } /* * In the case of tlb vma handling, we can optimise these away in the * case where we're doing a full MM flush. When we're doing a munmap, * the vmas are adjusted to only cover the region to be torn down. */ static inline void tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma) { if (!tlb->fullmm) { flush_cache_range(vma, vma->vm_start, vma->vm_end); tlb->vma = vma; tlb->range_start = TASK_SIZE; tlb->range_end = 0; } } static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma) { if (!tlb->fullmm) tlb_flush(tlb); } static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page) { tlb->pages[tlb->nr++] = page; VM_BUG_ON(tlb->nr > tlb->max); return tlb->max - tlb->nr; } static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page) { if (!__tlb_remove_page(tlb, page)) tlb_flush_mmu(tlb); } static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte, unsigned long addr) { pgtable_page_dtor(pte); #ifdef CONFIG_ARM_LPAE tlb_add_flush(tlb, addr); #else /* * With the classic ARM MMU, a pte page has two corresponding pmd * entries, each covering 1MB. */ addr &= PMD_MASK; tlb_add_flush(tlb, addr + SZ_1M - PAGE_SIZE); tlb_add_flush(tlb, addr + SZ_1M); #endif tlb_remove_page(tlb, pte); } static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp, unsigned long addr) { #ifdef CONFIG_ARM_LPAE tlb_add_flush(tlb, addr); tlb_remove_page(tlb, virt_to_page(pmdp)); #endif } static inline void tlb_remove_pmd_tlb_entry(struct mmu_gather *tlb, pmd_t *pmdp, unsigned long addr) { tlb_add_flush(tlb, addr); } #define pte_free_tlb(tlb, ptep, addr) __pte_free_tlb(tlb, ptep, addr) #define pmd_free_tlb(tlb, pmdp, addr) __pmd_free_tlb(tlb, pmdp, addr) #define pud_free_tlb(tlb, pudp, addr) pud_free((tlb)->mm, pudp) #define tlb_migrate_finish(mm) do { } while (0) #endif /* CONFIG_MMU */ #endif