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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 422 | giacomo | 1 | /* asm-generic/tlb.h |
| 2 | * |
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| 3 | * Generic TLB shootdown code |
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| 4 | * |
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| 5 | * Copyright 2001 Red Hat, Inc. |
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| 6 | * Based on code from mm/memory.c Copyright Linus Torvalds and others. |
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| 7 | * |
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| 8 | * This program is free software; you can redistribute it and/or |
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| 9 | * modify it under the terms of the GNU General Public License |
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| 10 | * as published by the Free Software Foundation; either version |
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| 11 | * 2 of the License, or (at your option) any later version. |
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| 12 | */ |
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| 13 | #ifndef _ASM_GENERIC__TLB_H |
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| 14 | #define _ASM_GENERIC__TLB_H |
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| 15 | |||
| 16 | #include <linux/config.h> |
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| 17 | #include <linux/swap.h> |
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| 18 | #include <asm/tlbflush.h> |
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| 19 | |||
| 20 | /* |
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| 21 | * For UP we don't need to worry about TLB flush |
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| 22 | * and page free order so much.. |
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| 23 | */ |
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| 24 | #ifdef CONFIG_SMP |
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| 25 | #define FREE_PTE_NR 506 |
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| 26 | #define tlb_fast_mode(tlb) ((tlb)->nr == ~0U) |
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| 27 | #else |
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| 28 | #define FREE_PTE_NR 1 |
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| 29 | #define tlb_fast_mode(tlb) 1 |
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| 30 | #endif |
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| 31 | |||
| 32 | /* struct mmu_gather is an opaque type used by the mm code for passing around |
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| 33 | * any data needed by arch specific code for tlb_remove_page. This structure |
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| 34 | * can be per-CPU or per-MM as the page table lock is held for the duration of |
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| 35 | * TLB shootdown. |
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| 36 | */ |
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| 37 | struct mmu_gather { |
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| 38 | struct mm_struct *mm; |
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| 39 | unsigned int nr; /* set to ~0U means fast mode */ |
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| 40 | unsigned int need_flush;/* Really unmapped some ptes? */ |
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| 41 | unsigned int fullmm; /* non-zero means full mm flush */ |
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| 42 | unsigned long freed; |
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| 43 | struct page * pages[FREE_PTE_NR]; |
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| 44 | }; |
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| 45 | |||
| 46 | /* Users of the generic TLB shootdown code must declare this storage space. */ |
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| 47 | DECLARE_PER_CPU(struct mmu_gather, mmu_gathers); |
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| 48 | |||
| 49 | /* tlb_gather_mmu |
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| 50 | * Return a pointer to an initialized struct mmu_gather. |
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| 51 | */ |
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| 52 | static inline struct mmu_gather * |
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| 53 | tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush) |
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| 54 | { |
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| 55 | struct mmu_gather *tlb = &per_cpu(mmu_gathers, smp_processor_id()); |
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| 56 | |||
| 57 | tlb->mm = mm; |
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| 58 | |||
| 59 | /* Use fast mode if only one CPU is online */ |
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| 60 | tlb->nr = num_online_cpus() > 1 ? 0U : ~0U; |
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| 61 | |||
| 62 | tlb->fullmm = full_mm_flush; |
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| 63 | tlb->freed = 0; |
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| 64 | |||
| 65 | return tlb; |
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| 66 | } |
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| 67 | |||
| 68 | static inline void |
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| 69 | tlb_flush_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end) |
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| 70 | { |
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| 71 | if (!tlb->need_flush) |
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| 72 | return; |
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| 73 | tlb->need_flush = 0; |
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| 74 | tlb_flush(tlb); |
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| 75 | if (!tlb_fast_mode(tlb)) { |
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| 76 | free_pages_and_swap_cache(tlb->pages, tlb->nr); |
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| 77 | tlb->nr = 0; |
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| 78 | } |
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| 79 | } |
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| 80 | |||
| 81 | /* tlb_finish_mmu |
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| 82 | * Called at the end of the shootdown operation to free up any resources |
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| 83 | * that were required. The page table lock is still held at this point. |
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| 84 | */ |
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| 85 | static inline void |
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| 86 | tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end) |
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| 87 | { |
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| 88 | int freed = tlb->freed; |
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| 89 | struct mm_struct *mm = tlb->mm; |
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| 90 | int rss = mm->rss; |
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| 91 | |||
| 92 | if (rss < freed) |
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| 93 | freed = rss; |
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| 94 | mm->rss = rss - freed; |
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| 95 | tlb_flush_mmu(tlb, start, end); |
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| 96 | |||
| 97 | /* keep the page table cache within bounds */ |
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| 98 | check_pgt_cache(); |
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| 99 | } |
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| 100 | |||
| 101 | |||
| 102 | /* tlb_remove_page |
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| 103 | * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while |
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| 104 | * handling the additional races in SMP caused by other CPUs caching valid |
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| 105 | * mappings in their TLBs. |
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| 106 | */ |
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| 107 | static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page) |
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| 108 | { |
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| 109 | tlb->need_flush = 1; |
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| 110 | if (tlb_fast_mode(tlb)) { |
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| 111 | free_page_and_swap_cache(page); |
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| 112 | return; |
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| 113 | } |
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| 114 | tlb->pages[tlb->nr++] = page; |
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| 115 | if (tlb->nr >= FREE_PTE_NR) |
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| 116 | tlb_flush_mmu(tlb, 0, 0); |
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| 117 | } |
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| 118 | |||
| 119 | /** |
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| 120 | * tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation. |
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| 121 | * |
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| 122 | * Record the fact that pte's were really umapped in ->need_flush, so we can |
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| 123 | * later optimise away the tlb invalidate. This helps when userspace is |
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| 124 | * unmapping already-unmapped pages, which happens quite a lot. |
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| 125 | */ |
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| 126 | #define tlb_remove_tlb_entry(tlb, ptep, address) \ |
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| 127 | do { \ |
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| 128 | tlb->need_flush = 1; \ |
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| 129 | __tlb_remove_tlb_entry(tlb, ptep, address); \ |
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| 130 | } while (0) |
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| 131 | |||
| 132 | #define pte_free_tlb(tlb, ptep) \ |
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| 133 | do { \ |
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| 134 | tlb->need_flush = 1; \ |
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| 135 | __pte_free_tlb(tlb, ptep); \ |
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| 136 | } while (0) |
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| 137 | |||
| 138 | #define pmd_free_tlb(tlb, pmdp) \ |
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| 139 | do { \ |
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| 140 | tlb->need_flush = 1; \ |
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| 141 | __pmd_free_tlb(tlb, pmdp); \ |
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| 142 | } while (0) |
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| 143 | |||
| 144 | #endif /* _ASM_GENERIC__TLB_H */ |