1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
|
// SPDX-License-Identifier: GPL-2.0
/*
* Based upon linux/arch/m68k/mm/sun3mmu.c
* Based upon linux/arch/ppc/mm/mmu_context.c
*
* Implementations of mm routines specific to the Coldfire MMU.
*
* Copyright (c) 2008 Freescale Semiconductor, Inc.
*/
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/bootmem.h>
#include <linux/memblock.h>
#include <asm/setup.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/mmu_context.h>
#include <asm/mcf_pgalloc.h>
#include <asm/tlbflush.h>
#define KMAPAREA(x) ((x >= VMALLOC_START) && (x < KMAP_END))
mm_context_t next_mmu_context;
unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1];
atomic_t nr_free_contexts;
struct mm_struct *context_mm[LAST_CONTEXT+1];
unsigned long num_pages;
/*
* ColdFire paging_init derived from sun3.
*/
void __init paging_init(void)
{
pgd_t *pg_dir;
pte_t *pg_table;
unsigned long address, size;
unsigned long next_pgtable, bootmem_end;
unsigned long zones_size[MAX_NR_ZONES];
enum zone_type zone;
int i;
empty_zero_page = (void *) alloc_bootmem_pages(PAGE_SIZE);
memset((void *) empty_zero_page, 0, PAGE_SIZE);
pg_dir = swapper_pg_dir;
memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir));
size = num_pages * sizeof(pte_t);
size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1);
next_pgtable = (unsigned long) alloc_bootmem_pages(size);
bootmem_end = (next_pgtable + size + PAGE_SIZE) & PAGE_MASK;
pg_dir += PAGE_OFFSET >> PGDIR_SHIFT;
address = PAGE_OFFSET;
while (address < (unsigned long)high_memory) {
pg_table = (pte_t *) next_pgtable;
next_pgtable += PTRS_PER_PTE * sizeof(pte_t);
pgd_val(*pg_dir) = (unsigned long) pg_table;
pg_dir++;
/* now change pg_table to kernel virtual addresses */
for (i = 0; i < PTRS_PER_PTE; ++i, ++pg_table) {
pte_t pte = pfn_pte(virt_to_pfn(address), PAGE_INIT);
if (address >= (unsigned long) high_memory)
pte_val(pte) = 0;
set_pte(pg_table, pte);
address += PAGE_SIZE;
}
}
current->mm = NULL;
for (zone = 0; zone < MAX_NR_ZONES; zone++)
zones_size[zone] = 0x0;
zones_size[ZONE_DMA] = num_pages;
free_area_init(zones_size);
}
int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word)
{
unsigned long flags, mmuar, mmutr;
struct mm_struct *mm;
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
int asid;
local_irq_save(flags);
mmuar = (dtlb) ? mmu_read(MMUAR) :
regs->pc + (extension_word * sizeof(long));
mm = (!user_mode(regs) && KMAPAREA(mmuar)) ? &init_mm : current->mm;
if (!mm) {
local_irq_restore(flags);
return -1;
}
pgd = pgd_offset(mm, mmuar);
if (pgd_none(*pgd)) {
local_irq_restore(flags);
return -1;
}
pmd = pmd_offset(pgd, mmuar);
if (pmd_none(*pmd)) {
local_irq_restore(flags);
return -1;
}
pte = (KMAPAREA(mmuar)) ? pte_offset_kernel(pmd, mmuar)
: pte_offset_map(pmd, mmuar);
if (pte_none(*pte) || !pte_present(*pte)) {
local_irq_restore(flags);
return -1;
}
if (write) {
if (!pte_write(*pte)) {
local_irq_restore(flags);
return -1;
}
set_pte(pte, pte_mkdirty(*pte));
}
set_pte(pte, pte_mkyoung(*pte));
asid = mm->context & 0xff;
if (!pte_dirty(*pte) && !KMAPAREA(mmuar))
set_pte(pte, pte_wrprotect(*pte));
mmutr = (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) | MMUTR_V;
if ((mmuar < TASK_UNMAPPED_BASE) || (mmuar >= TASK_SIZE))
mmutr |= (pte->pte & CF_PAGE_MMUTR_MASK) >> CF_PAGE_MMUTR_SHIFT;
mmu_write(MMUTR, mmutr);
mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) |
((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X);
if (dtlb)
mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA);
else
mmu_write(MMUOR, MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA);
local_irq_restore(flags);
return 0;
}
void __init cf_bootmem_alloc(void)
{
unsigned long memstart;
/* _rambase and _ramend will be naturally page aligned */
m68k_memory[0].addr = _rambase;
m68k_memory[0].size = _ramend - _rambase;
memblock_add(m68k_memory[0].addr, m68k_memory[0].size);
/* compute total pages in system */
num_pages = PFN_DOWN(_ramend - _rambase);
/* page numbers */
memstart = PAGE_ALIGN(_ramstart);
min_low_pfn = PFN_DOWN(_rambase);
max_pfn = max_low_pfn = PFN_DOWN(_ramend);
high_memory = (void *)_ramend;
/* Reserve kernel text/data/bss */
memblock_reserve(_rambase, memstart - _rambase);
m68k_virt_to_node_shift = fls(_ramend - 1) - 6;
module_fixup(NULL, __start_fixup, __stop_fixup);
/* setup node data */
m68k_setup_node(0);
}
/*
* Initialize the context management stuff.
* The following was taken from arch/ppc/mmu_context.c
*/
void __init cf_mmu_context_init(void)
{
/*
* Some processors have too few contexts to reserve one for
* init_mm, and require using context 0 for a normal task.
* Other processors reserve the use of context zero for the kernel.
* This code assumes FIRST_CONTEXT < 32.
*/
context_map[0] = (1 << FIRST_CONTEXT) - 1;
next_mmu_context = FIRST_CONTEXT;
atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1);
}
/*
* Steal a context from a task that has one at the moment.
* This is only used on 8xx and 4xx and we presently assume that
* they don't do SMP. If they do then thicfpgalloc.hs will have to check
* whether the MM we steal is in use.
* We also assume that this is only used on systems that don't
* use an MMU hash table - this is true for 8xx and 4xx.
* This isn't an LRU system, it just frees up each context in
* turn (sort-of pseudo-random replacement :). This would be the
* place to implement an LRU scheme if anyone was motivated to do it.
* -- paulus
*/
void steal_context(void)
{
struct mm_struct *mm;
/*
* free up context `next_mmu_context'
* if we shouldn't free context 0, don't...
*/
if (next_mmu_context < FIRST_CONTEXT)
next_mmu_context = FIRST_CONTEXT;
mm = context_mm[next_mmu_context];
flush_tlb_mm(mm);
destroy_context(mm);
}
|
