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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
29#include <asm/system.h>
30#include <asm/segment.h>
31#include <asm/tlbflush.h>
32#include <asm/pgtable.h>
33#include <asm/mmu_context.h>
34#include <asm/spr_defs.h>
35
36#define NO_CONTEXT -1
37
38#define NUM_DTLB_SETS (1 << ((mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_NTS) >> \
39 SPR_DMMUCFGR_NTS_OFF))
40#define NUM_ITLB_SETS (1 << ((mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_NTS) >> \
41 SPR_IMMUCFGR_NTS_OFF))
42#define DTLB_OFFSET(addr) (((addr) >> PAGE_SHIFT) & (NUM_DTLB_SETS-1))
43#define ITLB_OFFSET(addr) (((addr) >> PAGE_SHIFT) & (NUM_ITLB_SETS-1))
44/*
45 * Invalidate all TLB entries.
46 *
47 * This comes down to setting the 'valid' bit for all xTLBMR registers to 0.
48 * Easiest way to accomplish this is to just zero out the xTLBMR register
49 * completely.
50 *
51 */
52
53void flush_tlb_all(void)
54{
55 int i;
56 unsigned long num_tlb_sets;
57
58 /* Determine number of sets for IMMU. */
59 /* FIXME: Assumption is I & D nsets equal. */
60 num_tlb_sets = NUM_ITLB_SETS;
61
62 for (i = 0; i < num_tlb_sets; i++) {
63 mtspr_off(SPR_DTLBMR_BASE(0), i, 0);
64 mtspr_off(SPR_ITLBMR_BASE(0), i, 0);
65 }
66}
67
68#define have_dtlbeir (mfspr(SPR_DMMUCFGR) & SPR_DMMUCFGR_TEIRI)
69#define have_itlbeir (mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_TEIRI)
70
71/*
72 * Invalidate a single page. This is what the xTLBEIR register is for.
73 *
74 * There's no point in checking the vma for PAGE_EXEC to determine whether it's
75 * the data or instruction TLB that should be flushed... that would take more
76 * than the few instructions that the following compiles down to!
77 *
78 * The case where we don't have the xTLBEIR register really only works for
79 * MMU's with a single way and is hard-coded that way.
80 */
81
82#define flush_dtlb_page_eir(addr) mtspr(SPR_DTLBEIR, addr)
83#define flush_dtlb_page_no_eir(addr) \
84 mtspr_off(SPR_DTLBMR_BASE(0), DTLB_OFFSET(addr), 0);
85
86#define flush_itlb_page_eir(addr) mtspr(SPR_ITLBEIR, addr)
87#define flush_itlb_page_no_eir(addr) \
88 mtspr_off(SPR_ITLBMR_BASE(0), ITLB_OFFSET(addr), 0);
89
90void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
91{
92 if (have_dtlbeir)
93 flush_dtlb_page_eir(addr);
94 else
95 flush_dtlb_page_no_eir(addr);
96
97 if (have_itlbeir)
98 flush_itlb_page_eir(addr);
99 else
100 flush_itlb_page_no_eir(addr);
101}
102
103void flush_tlb_range(struct vm_area_struct *vma,
104 unsigned long start, unsigned long end)
105{
106 int addr;
107 bool dtlbeir;
108 bool itlbeir;
109
110 dtlbeir = have_dtlbeir;
111 itlbeir = have_itlbeir;
112
113 for (addr = start; addr < end; addr += PAGE_SIZE) {
114 if (dtlbeir)
115 flush_dtlb_page_eir(addr);
116 else
117 flush_dtlb_page_no_eir(addr);
118
119 if (itlbeir)
120 flush_itlb_page_eir(addr);
121 else
122 flush_itlb_page_no_eir(addr);
123 }
124}
125
126/*
127 * Invalidate the selected mm context only.
128 *
129 * FIXME: Due to some bug here, we're flushing everything for now.
130 * This should be changed to loop over over mm and call flush_tlb_range.
131 */
132
133void flush_tlb_mm(struct mm_struct *mm)
134{
135
136 /* Was seeing bugs with the mm struct passed to us. Scrapped most of
137 this function. */
138 /* Several architctures do this */
139 flush_tlb_all();
140}
141
142/* called in schedule() just before actually doing the switch_to */
143
144void switch_mm(struct mm_struct *prev, struct mm_struct *next,
145 struct task_struct *next_tsk)
146{
147 /* remember the pgd for the fault handlers
148 * this is similar to the pgd register in some other CPU's.
149 * we need our own copy of it because current and active_mm
150 * might be invalid at points where we still need to derefer
151 * the pgd.
152 */
153 current_pgd = next->pgd;
154
155 /* We don't have context support implemented, so flush all
156 * entries belonging to previous map
157 */
158
159 if (prev != next)
160 flush_tlb_mm(prev);
161
162}
163
164/*
165 * Initialize the context related info for a new mm_struct
166 * instance.
167 */
168
169int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
170{
171 mm->context = NO_CONTEXT;
172 return 0;
173}
174
175/* called by __exit_mm to destroy the used MMU context if any before
176 * destroying the mm itself. this is only called when the last user of the mm
177 * drops it.
178 */
179
180void destroy_context(struct mm_struct *mm)
181{
182 flush_tlb_mm(mm);
183
184}
185
186/* called once during VM initialization, from init.c */
187
188void __init tlb_init(void)
189{
190 /* Do nothing... */
191 /* invalidate the entire TLB */
192 /* flush_tlb_all(); */
193}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * OpenRISC tlb.c
4 *
5 * Linux architectural port borrowing liberally from similar works of
6 * others. All original copyrights apply as per the original source
7 * declaration.
8 *
9 * Modifications for the OpenRISC architecture:
10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
11 * Copyright (C) 2010-2011 Julius Baxter <julius.baxter@orsoc.se>
12 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
13 */
14
15#include <linux/sched.h>
16#include <linux/kernel.h>
17#include <linux/errno.h>
18#include <linux/string.h>
19#include <linux/types.h>
20#include <linux/ptrace.h>
21#include <linux/mman.h>
22#include <linux/mm.h>
23#include <linux/init.h>
24
25#include <asm/tlbflush.h>
26#include <asm/pgtable.h>
27#include <asm/mmu_context.h>
28#include <asm/spr_defs.h>
29
30#define NO_CONTEXT -1
31
32#define NUM_DTLB_SETS (1 << ((mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_NTS) >> \
33 SPR_DMMUCFGR_NTS_OFF))
34#define NUM_ITLB_SETS (1 << ((mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_NTS) >> \
35 SPR_IMMUCFGR_NTS_OFF))
36#define DTLB_OFFSET(addr) (((addr) >> PAGE_SHIFT) & (NUM_DTLB_SETS-1))
37#define ITLB_OFFSET(addr) (((addr) >> PAGE_SHIFT) & (NUM_ITLB_SETS-1))
38/*
39 * Invalidate all TLB entries.
40 *
41 * This comes down to setting the 'valid' bit for all xTLBMR registers to 0.
42 * Easiest way to accomplish this is to just zero out the xTLBMR register
43 * completely.
44 *
45 */
46
47void local_flush_tlb_all(void)
48{
49 int i;
50 unsigned long num_tlb_sets;
51
52 /* Determine number of sets for IMMU. */
53 /* FIXME: Assumption is I & D nsets equal. */
54 num_tlb_sets = NUM_ITLB_SETS;
55
56 for (i = 0; i < num_tlb_sets; i++) {
57 mtspr_off(SPR_DTLBMR_BASE(0), i, 0);
58 mtspr_off(SPR_ITLBMR_BASE(0), i, 0);
59 }
60}
61
62#define have_dtlbeir (mfspr(SPR_DMMUCFGR) & SPR_DMMUCFGR_TEIRI)
63#define have_itlbeir (mfspr(SPR_IMMUCFGR) & SPR_IMMUCFGR_TEIRI)
64
65/*
66 * Invalidate a single page. This is what the xTLBEIR register is for.
67 *
68 * There's no point in checking the vma for PAGE_EXEC to determine whether it's
69 * the data or instruction TLB that should be flushed... that would take more
70 * than the few instructions that the following compiles down to!
71 *
72 * The case where we don't have the xTLBEIR register really only works for
73 * MMU's with a single way and is hard-coded that way.
74 */
75
76#define flush_dtlb_page_eir(addr) mtspr(SPR_DTLBEIR, addr)
77#define flush_dtlb_page_no_eir(addr) \
78 mtspr_off(SPR_DTLBMR_BASE(0), DTLB_OFFSET(addr), 0);
79
80#define flush_itlb_page_eir(addr) mtspr(SPR_ITLBEIR, addr)
81#define flush_itlb_page_no_eir(addr) \
82 mtspr_off(SPR_ITLBMR_BASE(0), ITLB_OFFSET(addr), 0);
83
84void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
85{
86 if (have_dtlbeir)
87 flush_dtlb_page_eir(addr);
88 else
89 flush_dtlb_page_no_eir(addr);
90
91 if (have_itlbeir)
92 flush_itlb_page_eir(addr);
93 else
94 flush_itlb_page_no_eir(addr);
95}
96
97void local_flush_tlb_range(struct vm_area_struct *vma,
98 unsigned long start, unsigned long end)
99{
100 int addr;
101 bool dtlbeir;
102 bool itlbeir;
103
104 dtlbeir = have_dtlbeir;
105 itlbeir = have_itlbeir;
106
107 for (addr = start; addr < end; addr += PAGE_SIZE) {
108 if (dtlbeir)
109 flush_dtlb_page_eir(addr);
110 else
111 flush_dtlb_page_no_eir(addr);
112
113 if (itlbeir)
114 flush_itlb_page_eir(addr);
115 else
116 flush_itlb_page_no_eir(addr);
117 }
118}
119
120/*
121 * Invalidate the selected mm context only.
122 *
123 * FIXME: Due to some bug here, we're flushing everything for now.
124 * This should be changed to loop over over mm and call flush_tlb_range.
125 */
126
127void local_flush_tlb_mm(struct mm_struct *mm)
128{
129
130 /* Was seeing bugs with the mm struct passed to us. Scrapped most of
131 this function. */
132 /* Several architctures do this */
133 local_flush_tlb_all();
134}
135
136/* called in schedule() just before actually doing the switch_to */
137
138void switch_mm(struct mm_struct *prev, struct mm_struct *next,
139 struct task_struct *next_tsk)
140{
141 /* remember the pgd for the fault handlers
142 * this is similar to the pgd register in some other CPU's.
143 * we need our own copy of it because current and active_mm
144 * might be invalid at points where we still need to derefer
145 * the pgd.
146 */
147 current_pgd[smp_processor_id()] = next->pgd;
148
149 /* We don't have context support implemented, so flush all
150 * entries belonging to previous map
151 */
152
153 if (prev != next)
154 local_flush_tlb_mm(prev);
155
156}
157
158/*
159 * Initialize the context related info for a new mm_struct
160 * instance.
161 */
162
163int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
164{
165 mm->context = NO_CONTEXT;
166 return 0;
167}
168
169/* called by __exit_mm to destroy the used MMU context if any before
170 * destroying the mm itself. this is only called when the last user of the mm
171 * drops it.
172 */
173
174void destroy_context(struct mm_struct *mm)
175{
176 flush_tlb_mm(mm);
177
178}
179
180/* called once during VM initialization, from init.c */
181
182void __init tlb_init(void)
183{
184 /* Do nothing... */
185 /* invalidate the entire TLB */
186 /* flush_tlb_all(); */
187}