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1 | /* |
2 | * OpenRISC tlb.c | |
3 | * | |
4 | * Linux architectural port borrowing liberally from similar works of | |
5 | * others. All original copyrights apply as per the original source | |
6 | * declaration. | |
7 | * | |
8 | * Modifications for the OpenRISC architecture: | |
9 | * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com> | |
10 | * Copyright (C) 2010-2011 Julius Baxter <julius.baxter@orsoc.se> | |
11 | * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> | |
12 | * | |
13 | * This program is free software; you can redistribute it and/or | |
14 | * modify it under the terms of the GNU General Public License | |
15 | * as published by the Free Software Foundation; either version | |
16 | * 2 of the License, or (at your option) any later version. | |
17 | */ | |
18 | ||
19 | #include <linux/sched.h> | |
20 | #include <linux/kernel.h> | |
21 | #include <linux/errno.h> | |
22 | #include <linux/string.h> | |
23 | #include <linux/types.h> | |
24 | #include <linux/ptrace.h> | |
25 | #include <linux/mman.h> | |
26 | #include <linux/mm.h> | |
27 | #include <linux/init.h> | |
28 | ||
61e85e36 JB |
29 | #include <asm/segment.h> |
30 | #include <asm/tlbflush.h> | |
31 | #include <asm/pgtable.h> | |
32 | #include <asm/mmu_context.h> | |
33 | #include <asm/spr_defs.h> | |
34 | ||
35 | #define NO_CONTEXT -1 | |
36 | ||
37 | #define NUM_DTLB_SETS (1 << ((mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_NTS) >> \ | |
38 | SPR_DMMUCFGR_NTS_OFF)) | |
39 | #define NUM_ITLB_SETS (1 << ((mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_NTS) >> \ | |
40 | SPR_IMMUCFGR_NTS_OFF)) | |
41 | #define DTLB_OFFSET(addr) (((addr) >> PAGE_SHIFT) & (NUM_DTLB_SETS-1)) | |
42 | #define ITLB_OFFSET(addr) (((addr) >> PAGE_SHIFT) & (NUM_ITLB_SETS-1)) | |
43 | /* | |
44 | * Invalidate all TLB entries. | |
45 | * | |
46 | * This comes down to setting the 'valid' bit for all xTLBMR registers to 0. | |
47 | * Easiest way to accomplish this is to just zero out the xTLBMR register | |
48 | * completely. | |
49 | * | |
50 | */ | |
51 | ||
52 | void flush_tlb_all(void) | |
53 | { | |
54 | int i; | |
55 | unsigned long num_tlb_sets; | |
56 | ||
57 | /* Determine number of sets for IMMU. */ | |
58 | /* FIXME: Assumption is I & D nsets equal. */ | |
59 | num_tlb_sets = NUM_ITLB_SETS; | |
60 | ||
61 | for (i = 0; i < num_tlb_sets; i++) { | |
62 | mtspr_off(SPR_DTLBMR_BASE(0), i, 0); | |
63 | mtspr_off(SPR_ITLBMR_BASE(0), i, 0); | |
64 | } | |
65 | } | |
66 | ||
67 | #define have_dtlbeir (mfspr(SPR_DMMUCFGR) & SPR_DMMUCFGR_TEIRI) | |
68 | #define have_itlbeir (mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_TEIRI) | |
69 | ||
70 | /* | |
71 | * Invalidate a single page. This is what the xTLBEIR register is for. | |
72 | * | |
73 | * There's no point in checking the vma for PAGE_EXEC to determine whether it's | |
74 | * the data or instruction TLB that should be flushed... that would take more | |
75 | * than the few instructions that the following compiles down to! | |
76 | * | |
77 | * The case where we don't have the xTLBEIR register really only works for | |
78 | * MMU's with a single way and is hard-coded that way. | |
79 | */ | |
80 | ||
81 | #define flush_dtlb_page_eir(addr) mtspr(SPR_DTLBEIR, addr) | |
82 | #define flush_dtlb_page_no_eir(addr) \ | |
83 | mtspr_off(SPR_DTLBMR_BASE(0), DTLB_OFFSET(addr), 0); | |
84 | ||
85 | #define flush_itlb_page_eir(addr) mtspr(SPR_ITLBEIR, addr) | |
86 | #define flush_itlb_page_no_eir(addr) \ | |
87 | mtspr_off(SPR_ITLBMR_BASE(0), ITLB_OFFSET(addr), 0); | |
88 | ||
89 | void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr) | |
90 | { | |
91 | if (have_dtlbeir) | |
92 | flush_dtlb_page_eir(addr); | |
93 | else | |
94 | flush_dtlb_page_no_eir(addr); | |
95 | ||
96 | if (have_itlbeir) | |
97 | flush_itlb_page_eir(addr); | |
98 | else | |
99 | flush_itlb_page_no_eir(addr); | |
100 | } | |
101 | ||
102 | void flush_tlb_range(struct vm_area_struct *vma, | |
103 | unsigned long start, unsigned long end) | |
104 | { | |
105 | int addr; | |
106 | bool dtlbeir; | |
107 | bool itlbeir; | |
108 | ||
109 | dtlbeir = have_dtlbeir; | |
110 | itlbeir = have_itlbeir; | |
111 | ||
112 | for (addr = start; addr < end; addr += PAGE_SIZE) { | |
113 | if (dtlbeir) | |
114 | flush_dtlb_page_eir(addr); | |
115 | else | |
116 | flush_dtlb_page_no_eir(addr); | |
117 | ||
118 | if (itlbeir) | |
119 | flush_itlb_page_eir(addr); | |
120 | else | |
121 | flush_itlb_page_no_eir(addr); | |
122 | } | |
123 | } | |
124 | ||
125 | /* | |
126 | * Invalidate the selected mm context only. | |
127 | * | |
128 | * FIXME: Due to some bug here, we're flushing everything for now. | |
129 | * This should be changed to loop over over mm and call flush_tlb_range. | |
130 | */ | |
131 | ||
132 | void flush_tlb_mm(struct mm_struct *mm) | |
133 | { | |
134 | ||
135 | /* Was seeing bugs with the mm struct passed to us. Scrapped most of | |
136 | this function. */ | |
137 | /* Several architctures do this */ | |
138 | flush_tlb_all(); | |
139 | } | |
140 | ||
141 | /* called in schedule() just before actually doing the switch_to */ | |
142 | ||
143 | void switch_mm(struct mm_struct *prev, struct mm_struct *next, | |
144 | struct task_struct *next_tsk) | |
145 | { | |
146 | /* remember the pgd for the fault handlers | |
147 | * this is similar to the pgd register in some other CPU's. | |
148 | * we need our own copy of it because current and active_mm | |
149 | * might be invalid at points where we still need to derefer | |
150 | * the pgd. | |
151 | */ | |
152 | current_pgd = next->pgd; | |
153 | ||
154 | /* We don't have context support implemented, so flush all | |
155 | * entries belonging to previous map | |
156 | */ | |
157 | ||
158 | if (prev != next) | |
159 | flush_tlb_mm(prev); | |
160 | ||
161 | } | |
162 | ||
163 | /* | |
164 | * Initialize the context related info for a new mm_struct | |
165 | * instance. | |
166 | */ | |
167 | ||
168 | int init_new_context(struct task_struct *tsk, struct mm_struct *mm) | |
169 | { | |
170 | mm->context = NO_CONTEXT; | |
171 | return 0; | |
172 | } | |
173 | ||
174 | /* called by __exit_mm to destroy the used MMU context if any before | |
175 | * destroying the mm itself. this is only called when the last user of the mm | |
176 | * drops it. | |
177 | */ | |
178 | ||
179 | void destroy_context(struct mm_struct *mm) | |
180 | { | |
181 | flush_tlb_mm(mm); | |
182 | ||
183 | } | |
184 | ||
185 | /* called once during VM initialization, from init.c */ | |
186 | ||
187 | void __init tlb_init(void) | |
188 | { | |
189 | /* Do nothing... */ | |
190 | /* invalidate the entire TLB */ | |
191 | /* flush_tlb_all(); */ | |
192 | } |