1 /* include/asm-generic/tlb.h
3 * Generic TLB shootdown code
5 * Copyright 2001 Red Hat, Inc.
6 * Based on code from mm/memory.c Copyright Linus Torvalds and others.
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License
10 * as published by the Free Software Foundation; either version
11 * 2 of the License, or (at your option) any later version.
13 #ifndef _ASM_GENERIC__TLB_H
14 #define _ASM_GENERIC__TLB_H
16 #include <linux/swap.h>
17 #include <asm/pgalloc.h>
18 #include <asm/tlbflush.h>
21 * For UP we don't need to worry about TLB flush
22 * and page free order so much..
25 #ifdef ARCH_FREE_PTR_NR
26 #define FREE_PTR_NR ARCH_FREE_PTR_NR
28 #define FREE_PTE_NR 506
30 #define tlb_fast_mode(tlb) ((tlb)->nr == ~0U)
33 #define tlb_fast_mode(tlb) 1
36 /* struct mmu_gather is an opaque type used by the mm code for passing around
37 * any data needed by arch specific code for tlb_remove_page.
41 unsigned int nr
; /* set to ~0U means fast mode */
42 unsigned int need_flush
;/* Really unmapped some ptes? */
43 unsigned int fullmm
; /* non-zero means full mm flush */
44 struct page
* pages
[FREE_PTE_NR
];
47 /* Users of the generic TLB shootdown code must declare this storage space. */
48 DECLARE_PER_CPU(struct mmu_gather
, mmu_gathers
);
51 * Return a pointer to an initialized struct mmu_gather.
53 static inline struct mmu_gather
*
54 tlb_gather_mmu(struct mm_struct
*mm
, unsigned int full_mm_flush
)
56 struct mmu_gather
*tlb
= &get_cpu_var(mmu_gathers
);
60 /* Use fast mode if only one CPU is online */
61 tlb
->nr
= num_online_cpus() > 1 ? 0U : ~0U;
63 tlb
->fullmm
= full_mm_flush
;
69 tlb_flush_mmu(struct mmu_gather
*tlb
, unsigned long start
, unsigned long end
)
75 if (!tlb_fast_mode(tlb
)) {
76 free_pages_and_swap_cache(tlb
->pages
, tlb
->nr
);
82 * Called at the end of the shootdown operation to free up any resources
86 tlb_finish_mmu(struct mmu_gather
*tlb
, unsigned long start
, unsigned long end
)
88 tlb_flush_mmu(tlb
, start
, end
);
90 /* keep the page table cache within bounds */
93 put_cpu_var(mmu_gathers
);
97 * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
98 * handling the additional races in SMP caused by other CPUs caching valid
99 * mappings in their TLBs.
101 static inline void tlb_remove_page(struct mmu_gather
*tlb
, struct page
*page
)
104 if (tlb_fast_mode(tlb
)) {
105 free_page_and_swap_cache(page
);
108 tlb
->pages
[tlb
->nr
++] = page
;
109 if (tlb
->nr
>= FREE_PTE_NR
)
110 tlb_flush_mmu(tlb
, 0, 0);
114 * tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation.
116 * Record the fact that pte's were really umapped in ->need_flush, so we can
117 * later optimise away the tlb invalidate. This helps when userspace is
118 * unmapping already-unmapped pages, which happens quite a lot.
120 #define tlb_remove_tlb_entry(tlb, ptep, address) \
122 tlb->need_flush = 1; \
123 __tlb_remove_tlb_entry(tlb, ptep, address); \
126 #define pte_free_tlb(tlb, ptep, address) \
128 tlb->need_flush = 1; \
129 __pte_free_tlb(tlb, ptep, address); \
132 #ifndef __ARCH_HAS_4LEVEL_HACK
133 #define pud_free_tlb(tlb, pudp, address) \
135 tlb->need_flush = 1; \
136 __pud_free_tlb(tlb, pudp, address); \
140 #define pmd_free_tlb(tlb, pmdp, address) \
142 tlb->need_flush = 1; \
143 __pmd_free_tlb(tlb, pmdp, address); \
146 #define tlb_migrate_finish(mm) do {} while (0)
148 #endif /* _ASM_GENERIC__TLB_H */
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