Commit | Line | Data |
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f30c2269 | 1 | /* include/asm-generic/tlb.h |
1da177e4 LT |
2 | * |
3 | * Generic TLB shootdown code | |
4 | * | |
5 | * Copyright 2001 Red Hat, Inc. | |
6 | * Based on code from mm/memory.c Copyright Linus Torvalds and others. | |
7 | * | |
d16dfc55 PZ |
8 | * Copyright 2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> |
9 | * | |
1da177e4 LT |
10 | * This program is free software; you can redistribute it and/or |
11 | * modify it under the terms of the GNU General Public License | |
12 | * as published by the Free Software Foundation; either version | |
13 | * 2 of the License, or (at your option) any later version. | |
14 | */ | |
15 | #ifndef _ASM_GENERIC__TLB_H | |
16 | #define _ASM_GENERIC__TLB_H | |
17 | ||
1da177e4 | 18 | #include <linux/swap.h> |
62152d0e | 19 | #include <asm/pgalloc.h> |
1da177e4 LT |
20 | #include <asm/tlbflush.h> |
21 | ||
26723911 PZ |
22 | #ifdef CONFIG_HAVE_RCU_TABLE_FREE |
23 | /* | |
24 | * Semi RCU freeing of the page directories. | |
25 | * | |
26 | * This is needed by some architectures to implement software pagetable walkers. | |
27 | * | |
28 | * gup_fast() and other software pagetable walkers do a lockless page-table | |
29 | * walk and therefore needs some synchronization with the freeing of the page | |
30 | * directories. The chosen means to accomplish that is by disabling IRQs over | |
31 | * the walk. | |
32 | * | |
33 | * Architectures that use IPIs to flush TLBs will then automagically DTRT, | |
34 | * since we unlink the page, flush TLBs, free the page. Since the disabling of | |
35 | * IRQs delays the completion of the TLB flush we can never observe an already | |
36 | * freed page. | |
37 | * | |
38 | * Architectures that do not have this (PPC) need to delay the freeing by some | |
39 | * other means, this is that means. | |
40 | * | |
41 | * What we do is batch the freed directory pages (tables) and RCU free them. | |
42 | * We use the sched RCU variant, as that guarantees that IRQ/preempt disabling | |
43 | * holds off grace periods. | |
44 | * | |
45 | * However, in order to batch these pages we need to allocate storage, this | |
46 | * allocation is deep inside the MM code and can thus easily fail on memory | |
47 | * pressure. To guarantee progress we fall back to single table freeing, see | |
48 | * the implementation of tlb_remove_table_one(). | |
49 | * | |
50 | */ | |
51 | struct mmu_table_batch { | |
52 | struct rcu_head rcu; | |
53 | unsigned int nr; | |
54 | void *tables[0]; | |
55 | }; | |
56 | ||
57 | #define MAX_TABLE_BATCH \ | |
58 | ((PAGE_SIZE - sizeof(struct mmu_table_batch)) / sizeof(void *)) | |
59 | ||
60 | extern void tlb_table_flush(struct mmu_gather *tlb); | |
61 | extern void tlb_remove_table(struct mmu_gather *tlb, void *table); | |
62 | ||
63 | #endif | |
64 | ||
d16dfc55 PZ |
65 | /* |
66 | * If we can't allocate a page to make a big batch of page pointers | |
67 | * to work on, then just handle a few from the on-stack structure. | |
68 | */ | |
69 | #define MMU_GATHER_BUNDLE 8 | |
70 | ||
e303297e PZ |
71 | struct mmu_gather_batch { |
72 | struct mmu_gather_batch *next; | |
73 | unsigned int nr; | |
74 | unsigned int max; | |
75 | struct page *pages[0]; | |
76 | }; | |
77 | ||
78 | #define MAX_GATHER_BATCH \ | |
79 | ((PAGE_SIZE - sizeof(struct mmu_gather_batch)) / sizeof(void *)) | |
80 | ||
53a59fc6 MH |
81 | /* |
82 | * Limit the maximum number of mmu_gather batches to reduce a risk of soft | |
83 | * lockups for non-preemptible kernels on huge machines when a lot of memory | |
84 | * is zapped during unmapping. | |
85 | * 10K pages freed at once should be safe even without a preemption point. | |
86 | */ | |
87 | #define MAX_GATHER_BATCH_COUNT (10000UL/MAX_GATHER_BATCH) | |
88 | ||
1da177e4 | 89 | /* struct mmu_gather is an opaque type used by the mm code for passing around |
15a23ffa | 90 | * any data needed by arch specific code for tlb_remove_page. |
1da177e4 LT |
91 | */ |
92 | struct mmu_gather { | |
93 | struct mm_struct *mm; | |
26723911 PZ |
94 | #ifdef CONFIG_HAVE_RCU_TABLE_FREE |
95 | struct mmu_table_batch *batch; | |
96 | #endif | |
597e1c35 AS |
97 | unsigned long start; |
98 | unsigned long end; | |
e303297e PZ |
99 | unsigned int need_flush : 1, /* Did free PTEs */ |
100 | fast_mode : 1; /* No batching */ | |
101 | ||
102 | unsigned int fullmm; | |
103 | ||
104 | struct mmu_gather_batch *active; | |
105 | struct mmu_gather_batch local; | |
106 | struct page *__pages[MMU_GATHER_BUNDLE]; | |
53a59fc6 | 107 | unsigned int batch_count; |
1da177e4 LT |
108 | }; |
109 | ||
9547d01b | 110 | #define HAVE_GENERIC_MMU_GATHER |
e303297e | 111 | |
9547d01b | 112 | static inline int tlb_fast_mode(struct mmu_gather *tlb) |
d16dfc55 | 113 | { |
9547d01b PZ |
114 | #ifdef CONFIG_SMP |
115 | return tlb->fast_mode; | |
116 | #else | |
117 | /* | |
118 | * For UP we don't need to worry about TLB flush | |
119 | * and page free order so much.. | |
120 | */ | |
e303297e | 121 | return 1; |
d16dfc55 | 122 | #endif |
1da177e4 LT |
123 | } |
124 | ||
9547d01b PZ |
125 | void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm); |
126 | void tlb_flush_mmu(struct mmu_gather *tlb); | |
c4211f42 AS |
127 | void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, |
128 | unsigned long end); | |
9547d01b | 129 | int __tlb_remove_page(struct mmu_gather *tlb, struct page *page); |
d16dfc55 PZ |
130 | |
131 | /* tlb_remove_page | |
132 | * Similar to __tlb_remove_page but will call tlb_flush_mmu() itself when | |
133 | * required. | |
134 | */ | |
135 | static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page) | |
136 | { | |
137 | if (!__tlb_remove_page(tlb, page)) | |
138 | tlb_flush_mmu(tlb); | |
1da177e4 LT |
139 | } |
140 | ||
141 | /** | |
142 | * tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation. | |
143 | * | |
144 | * Record the fact that pte's were really umapped in ->need_flush, so we can | |
145 | * later optimise away the tlb invalidate. This helps when userspace is | |
146 | * unmapping already-unmapped pages, which happens quite a lot. | |
147 | */ | |
148 | #define tlb_remove_tlb_entry(tlb, ptep, address) \ | |
149 | do { \ | |
150 | tlb->need_flush = 1; \ | |
151 | __tlb_remove_tlb_entry(tlb, ptep, address); \ | |
152 | } while (0) | |
153 | ||
f21760b1 SL |
154 | /** |
155 | * tlb_remove_pmd_tlb_entry - remember a pmd mapping for later tlb invalidation | |
156 | * This is a nop so far, because only x86 needs it. | |
157 | */ | |
158 | #ifndef __tlb_remove_pmd_tlb_entry | |
159 | #define __tlb_remove_pmd_tlb_entry(tlb, pmdp, address) do {} while (0) | |
160 | #endif | |
161 | ||
162 | #define tlb_remove_pmd_tlb_entry(tlb, pmdp, address) \ | |
163 | do { \ | |
164 | tlb->need_flush = 1; \ | |
165 | __tlb_remove_pmd_tlb_entry(tlb, pmdp, address); \ | |
166 | } while (0) | |
167 | ||
9e1b32ca | 168 | #define pte_free_tlb(tlb, ptep, address) \ |
1da177e4 LT |
169 | do { \ |
170 | tlb->need_flush = 1; \ | |
9e1b32ca | 171 | __pte_free_tlb(tlb, ptep, address); \ |
1da177e4 LT |
172 | } while (0) |
173 | ||
174 | #ifndef __ARCH_HAS_4LEVEL_HACK | |
9e1b32ca | 175 | #define pud_free_tlb(tlb, pudp, address) \ |
1da177e4 LT |
176 | do { \ |
177 | tlb->need_flush = 1; \ | |
9e1b32ca | 178 | __pud_free_tlb(tlb, pudp, address); \ |
1da177e4 LT |
179 | } while (0) |
180 | #endif | |
181 | ||
9e1b32ca | 182 | #define pmd_free_tlb(tlb, pmdp, address) \ |
1da177e4 LT |
183 | do { \ |
184 | tlb->need_flush = 1; \ | |
9e1b32ca | 185 | __pmd_free_tlb(tlb, pmdp, address); \ |
1da177e4 LT |
186 | } while (0) |
187 | ||
188 | #define tlb_migrate_finish(mm) do {} while (0) | |
189 | ||
190 | #endif /* _ASM_GENERIC__TLB_H */ |