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1 /*
2  * This file contains the routines for TLB flushing.
3  * On machines where the MMU uses a hash table to store virtual to
4  * physical translations, these routines flush entries from the
5  * hash table also.
6  *  -- paulus
7  *
8  *  Derived from arch/ppc/mm/init.c:
9  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
10  *
11  *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
12  *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
13  *    Copyright (C) 1996 Paul Mackerras
14  *
15  *  Derived from "arch/i386/mm/init.c"
16  *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
17  *
18  *  This program is free software; you can redistribute it and/or
19  *  modify it under the terms of the GNU General Public License
20  *  as published by the Free Software Foundation; either version
21  *  2 of the License, or (at your option) any later version.
22  *
23  */
24 
25 #include <linux/kernel.h>
26 #include <linux/mm.h>
27 #include <linux/init.h>
28 #include <linux/highmem.h>
29 #include <linux/pagemap.h>
30 #include <linux/export.h>
31 
32 #include <asm/tlbflush.h>
33 #include <asm/tlb.h>
34 
35 #include "mmu_decl.h"
36 
37 /*
38  * Called when unmapping pages to flush entries from the TLB/hash table.
39  */
flush_hash_entry(struct mm_struct * mm,pte_t * ptep,unsigned long addr)40 void flush_hash_entry(struct mm_struct *mm, pte_t *ptep, unsigned long addr)
41 {
42 	unsigned long ptephys;
43 
44 	if (Hash != 0) {
45 		ptephys = __pa(ptep) & PAGE_MASK;
46 		flush_hash_pages(mm->context.id, addr, ptephys, 1);
47 	}
48 }
49 EXPORT_SYMBOL(flush_hash_entry);
50 
51 /*
52  * Called by ptep_set_access_flags, must flush on CPUs for which the
53  * DSI handler can't just "fixup" the TLB on a write fault
54  */
flush_tlb_page_nohash(struct vm_area_struct * vma,unsigned long addr)55 void flush_tlb_page_nohash(struct vm_area_struct *vma, unsigned long addr)
56 {
57 	if (Hash != 0)
58 		return;
59 	_tlbie(addr);
60 }
61 
62 /*
63  * Called at the end of a mmu_gather operation to make sure the
64  * TLB flush is completely done.
65  */
tlb_flush(struct mmu_gather * tlb)66 void tlb_flush(struct mmu_gather *tlb)
67 {
68 	if (Hash == 0) {
69 		/*
70 		 * 603 needs to flush the whole TLB here since
71 		 * it doesn't use a hash table.
72 		 */
73 		_tlbia();
74 	}
75 }
76 
77 /*
78  * TLB flushing:
79  *
80  *  - flush_tlb_mm(mm) flushes the specified mm context TLB's
81  *  - flush_tlb_page(vma, vmaddr) flushes one page
82  *  - flush_tlb_range(vma, start, end) flushes a range of pages
83  *  - flush_tlb_kernel_range(start, end) flushes kernel pages
84  *
85  * since the hardware hash table functions as an extension of the
86  * tlb as far as the linux tables are concerned, flush it too.
87  *    -- Cort
88  */
89 
flush_range(struct mm_struct * mm,unsigned long start,unsigned long end)90 static void flush_range(struct mm_struct *mm, unsigned long start,
91 			unsigned long end)
92 {
93 	pmd_t *pmd;
94 	unsigned long pmd_end;
95 	int count;
96 	unsigned int ctx = mm->context.id;
97 
98 	if (Hash == 0) {
99 		_tlbia();
100 		return;
101 	}
102 	start &= PAGE_MASK;
103 	if (start >= end)
104 		return;
105 	end = (end - 1) | ~PAGE_MASK;
106 	pmd = pmd_offset(pud_offset(pgd_offset(mm, start), start), start);
107 	for (;;) {
108 		pmd_end = ((start + PGDIR_SIZE) & PGDIR_MASK) - 1;
109 		if (pmd_end > end)
110 			pmd_end = end;
111 		if (!pmd_none(*pmd)) {
112 			count = ((pmd_end - start) >> PAGE_SHIFT) + 1;
113 			flush_hash_pages(ctx, start, pmd_val(*pmd), count);
114 		}
115 		if (pmd_end == end)
116 			break;
117 		start = pmd_end + 1;
118 		++pmd;
119 	}
120 }
121 
122 /*
123  * Flush kernel TLB entries in the given range
124  */
flush_tlb_kernel_range(unsigned long start,unsigned long end)125 void flush_tlb_kernel_range(unsigned long start, unsigned long end)
126 {
127 	flush_range(&init_mm, start, end);
128 }
129 EXPORT_SYMBOL(flush_tlb_kernel_range);
130 
131 /*
132  * Flush all the (user) entries for the address space described by mm.
133  */
flush_tlb_mm(struct mm_struct * mm)134 void flush_tlb_mm(struct mm_struct *mm)
135 {
136 	struct vm_area_struct *mp;
137 
138 	if (Hash == 0) {
139 		_tlbia();
140 		return;
141 	}
142 
143 	/*
144 	 * It is safe to go down the mm's list of vmas when called
145 	 * from dup_mmap, holding mmap_sem.  It would also be safe from
146 	 * unmap_region or exit_mmap, but not from vmtruncate on SMP -
147 	 * but it seems dup_mmap is the only SMP case which gets here.
148 	 */
149 	for (mp = mm->mmap; mp != NULL; mp = mp->vm_next)
150 		flush_range(mp->vm_mm, mp->vm_start, mp->vm_end);
151 }
152 EXPORT_SYMBOL(flush_tlb_mm);
153 
flush_tlb_page(struct vm_area_struct * vma,unsigned long vmaddr)154 void flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
155 {
156 	struct mm_struct *mm;
157 	pmd_t *pmd;
158 
159 	if (Hash == 0) {
160 		_tlbie(vmaddr);
161 		return;
162 	}
163 	mm = (vmaddr < TASK_SIZE)? vma->vm_mm: &init_mm;
164 	pmd = pmd_offset(pud_offset(pgd_offset(mm, vmaddr), vmaddr), vmaddr);
165 	if (!pmd_none(*pmd))
166 		flush_hash_pages(mm->context.id, vmaddr, pmd_val(*pmd), 1);
167 }
168 EXPORT_SYMBOL(flush_tlb_page);
169 
170 /*
171  * For each address in the range, find the pte for the address
172  * and check _PAGE_HASHPTE bit; if it is set, find and destroy
173  * the corresponding HPTE.
174  */
flush_tlb_range(struct vm_area_struct * vma,unsigned long start,unsigned long end)175 void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
176 		     unsigned long end)
177 {
178 	flush_range(vma->vm_mm, start, end);
179 }
180 EXPORT_SYMBOL(flush_tlb_range);
181 
early_init_mmu(void)182 void __init early_init_mmu(void)
183 {
184 }
185