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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Russell King4baa9922008-08-02 10:55:55 +01002 * arch/arm/include/asm/tlb.h
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
4 * Copyright (C) 2002 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 * Experimentation shows that on a StrongARM, it appears to be faster
11 * to use the "invalidate whole tlb" rather than "invalidate single
12 * tlb" for this.
13 *
14 * This appears true for both the process fork+exit case, as well as
15 * the munmap-large-area case.
16 */
17#ifndef __ASMARM_TLB_H
18#define __ASMARM_TLB_H
19
20#include <asm/cacheflush.h>
Hyok S. Choi01579032006-02-24 21:41:25 +000021
22#ifndef CONFIG_MMU
23
24#include <linux/pagemap.h>
Russell King58e9c472011-02-20 12:27:49 +000025
26#define tlb_flush(tlb) ((void) tlb)
27
Hyok S. Choi01579032006-02-24 21:41:25 +000028#include <asm-generic/tlb.h>
29
30#else /* !CONFIG_MMU */
31
Russell King06824ba2011-02-20 12:16:45 +000032#include <linux/swap.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070033#include <asm/pgalloc.h>
Russell King06824ba2011-02-20 12:16:45 +000034#include <asm/tlbflush.h>
35
36/*
37 * We need to delay page freeing for SMP as other CPUs can access pages
38 * which have been removed but not yet had their TLB entries invalidated.
39 * Also, as ARMv7 speculative prefetch can drag new entries into the TLB,
40 * we need to apply this same delaying tactic to ensure correct operation.
41 */
42#if defined(CONFIG_SMP) || defined(CONFIG_CPU_32v7)
43#define tlb_fast_mode(tlb) 0
Russell King06824ba2011-02-20 12:16:45 +000044#else
45#define tlb_fast_mode(tlb) 1
Russell King06824ba2011-02-20 12:16:45 +000046#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070047
Peter Zijlstra9e14f672011-05-24 17:11:53 -070048#define MMU_GATHER_BUNDLE 8
49
Linus Torvalds1da177e2005-04-16 15:20:36 -070050/*
51 * TLB handling. This allows us to remove pages from the page
52 * tables, and efficiently handle the TLB issues.
53 */
54struct mmu_gather {
55 struct mm_struct *mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 unsigned int fullmm;
Russell King06824ba2011-02-20 12:16:45 +000057 struct vm_area_struct *vma;
Aaro Koskinen7fccfc02009-04-14 13:07:35 +010058 unsigned long range_start;
59 unsigned long range_end;
Russell King06824ba2011-02-20 12:16:45 +000060 unsigned int nr;
Peter Zijlstra9e14f672011-05-24 17:11:53 -070061 unsigned int max;
62 struct page **pages;
63 struct page *local[MMU_GATHER_BUNDLE];
Linus Torvalds1da177e2005-04-16 15:20:36 -070064};
65
66DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
67
Russell King06824ba2011-02-20 12:16:45 +000068/*
69 * This is unnecessarily complex. There's three ways the TLB shootdown
70 * code is used:
71 * 1. Unmapping a range of vmas. See zap_page_range(), unmap_region().
72 * tlb->fullmm = 0, and tlb_start_vma/tlb_end_vma will be called.
73 * tlb->vma will be non-NULL.
74 * 2. Unmapping all vmas. See exit_mmap().
75 * tlb->fullmm = 1, and tlb_start_vma/tlb_end_vma will be called.
76 * tlb->vma will be non-NULL. Additionally, page tables will be freed.
77 * 3. Unmapping argument pages. See shift_arg_pages().
78 * tlb->fullmm = 0, but tlb_start_vma/tlb_end_vma will not be called.
79 * tlb->vma will be NULL.
80 */
81static inline void tlb_flush(struct mmu_gather *tlb)
82{
83 if (tlb->fullmm || !tlb->vma)
84 flush_tlb_mm(tlb->mm);
85 else if (tlb->range_end > 0) {
86 flush_tlb_range(tlb->vma, tlb->range_start, tlb->range_end);
87 tlb->range_start = TASK_SIZE;
88 tlb->range_end = 0;
89 }
90}
91
92static inline void tlb_add_flush(struct mmu_gather *tlb, unsigned long addr)
93{
94 if (!tlb->fullmm) {
95 if (addr < tlb->range_start)
96 tlb->range_start = addr;
97 if (addr + PAGE_SIZE > tlb->range_end)
98 tlb->range_end = addr + PAGE_SIZE;
99 }
100}
101
Peter Zijlstra9e14f672011-05-24 17:11:53 -0700102static inline void __tlb_alloc_page(struct mmu_gather *tlb)
103{
104 unsigned long addr = __get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
105
106 if (addr) {
107 tlb->pages = (void *)addr;
108 tlb->max = PAGE_SIZE / sizeof(struct page *);
109 }
110}
111
Russell King06824ba2011-02-20 12:16:45 +0000112static inline void tlb_flush_mmu(struct mmu_gather *tlb)
113{
114 tlb_flush(tlb);
115 if (!tlb_fast_mode(tlb)) {
116 free_pages_and_swap_cache(tlb->pages, tlb->nr);
117 tlb->nr = 0;
Peter Zijlstra9e14f672011-05-24 17:11:53 -0700118 if (tlb->pages == tlb->local)
119 __tlb_alloc_page(tlb);
Russell King06824ba2011-02-20 12:16:45 +0000120 }
121}
122
Peter Zijlstra9e14f672011-05-24 17:11:53 -0700123static inline void
124tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned int fullmm)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126 tlb->mm = mm;
Peter Zijlstra9e14f672011-05-24 17:11:53 -0700127 tlb->fullmm = fullmm;
Russell King06824ba2011-02-20 12:16:45 +0000128 tlb->vma = NULL;
Peter Zijlstra9e14f672011-05-24 17:11:53 -0700129 tlb->max = ARRAY_SIZE(tlb->local);
130 tlb->pages = tlb->local;
Russell King06824ba2011-02-20 12:16:45 +0000131 tlb->nr = 0;
Peter Zijlstra9e14f672011-05-24 17:11:53 -0700132 __tlb_alloc_page(tlb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133}
134
135static inline void
136tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
137{
Russell King06824ba2011-02-20 12:16:45 +0000138 tlb_flush_mmu(tlb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139
140 /* keep the page table cache within bounds */
141 check_pgt_cache();
Hugh Dickins15a23ff2005-10-29 18:16:01 -0700142
Peter Zijlstra9e14f672011-05-24 17:11:53 -0700143 if (tlb->pages != tlb->local)
144 free_pages((unsigned long)tlb->pages, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145}
146
Aaro Koskinen7fccfc02009-04-14 13:07:35 +0100147/*
148 * Memorize the range for the TLB flush.
149 */
150static inline void
151tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep, unsigned long addr)
152{
Russell King06824ba2011-02-20 12:16:45 +0000153 tlb_add_flush(tlb, addr);
Aaro Koskinen7fccfc02009-04-14 13:07:35 +0100154}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155
156/*
157 * In the case of tlb vma handling, we can optimise these away in the
158 * case where we're doing a full MM flush. When we're doing a munmap,
159 * the vmas are adjusted to only cover the region to be torn down.
160 */
161static inline void
162tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
163{
Aaro Koskinen7fccfc02009-04-14 13:07:35 +0100164 if (!tlb->fullmm) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 flush_cache_range(vma, vma->vm_start, vma->vm_end);
Russell King06824ba2011-02-20 12:16:45 +0000166 tlb->vma = vma;
Aaro Koskinen7fccfc02009-04-14 13:07:35 +0100167 tlb->range_start = TASK_SIZE;
168 tlb->range_end = 0;
169 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170}
171
172static inline void
173tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
174{
Russell King06824ba2011-02-20 12:16:45 +0000175 if (!tlb->fullmm)
176 tlb_flush(tlb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177}
178
Peter Zijlstra9e14f672011-05-24 17:11:53 -0700179static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
Russell King06824ba2011-02-20 12:16:45 +0000180{
181 if (tlb_fast_mode(tlb)) {
182 free_page_and_swap_cache(page);
Peter Zijlstra9e14f672011-05-24 17:11:53 -0700183 return 1; /* avoid calling tlb_flush_mmu */
Russell King06824ba2011-02-20 12:16:45 +0000184 }
Peter Zijlstra9e14f672011-05-24 17:11:53 -0700185
186 tlb->pages[tlb->nr++] = page;
187 VM_BUG_ON(tlb->nr > tlb->max);
188 return tlb->max - tlb->nr;
189}
190
191static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
192{
193 if (!__tlb_remove_page(tlb, page))
194 tlb_flush_mmu(tlb);
Russell King06824ba2011-02-20 12:16:45 +0000195}
196
197static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
198 unsigned long addr)
199{
200 pgtable_page_dtor(pte);
201 tlb_add_flush(tlb, addr);
202 tlb_remove_page(tlb, pte);
203}
204
205#define pte_free_tlb(tlb, ptep, addr) __pte_free_tlb(tlb, ptep, addr)
Benjamin Herrenschmidt9e1b32c2009-07-22 15:44:28 +1000206#define pmd_free_tlb(tlb, pmdp, addr) pmd_free((tlb)->mm, pmdp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207
208#define tlb_migrate_finish(mm) do { } while (0)
209
Hyok S. Choi01579032006-02-24 21:41:25 +0000210#endif /* CONFIG_MMU */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211#endif