1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Based upon linux/arch/m68k/mm/sun3mmu.c
4 * Based upon linux/arch/ppc/mm/mmu_context.c
5 *
6 * Implementations of mm routines specific to the Coldfire MMU.
7 *
8 * Copyright (c) 2008 Freescale Semiconductor, Inc.
9 */
10
11 #include <linux/kernel.h>
12 #include <linux/types.h>
13 #include <linux/mm.h>
14 #include <linux/init.h>
15 #include <linux/string.h>
16 #include <linux/memblock.h>
17
18 #include <asm/setup.h>
19 #include <asm/page.h>
20 #include <asm/mmu_context.h>
21 #include <asm/mcf_pgalloc.h>
22 #include <asm/tlbflush.h>
23 #include <asm/pgalloc.h>
24
25 #define KMAPAREA(x) ((x >= VMALLOC_START) && (x < KMAP_END))
26
27 mm_context_t next_mmu_context;
28 unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1];
29 atomic_t nr_free_contexts;
30 struct mm_struct *context_mm[LAST_CONTEXT+1];
31 unsigned long num_pages;
32
33 /*
34 * ColdFire paging_init derived from sun3.
35 */
paging_init(void)36 void __init paging_init(void)
37 {
38 pgd_t *pg_dir;
39 pte_t *pg_table;
40 unsigned long address, size;
41 unsigned long next_pgtable;
42 int i;
43
44 empty_zero_page = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);
45
46 pg_dir = swapper_pg_dir;
47 memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir));
48
49 size = num_pages * sizeof(pte_t);
50 size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1);
51 next_pgtable = (unsigned long) memblock_alloc_or_panic(size, PAGE_SIZE);
52
53 pg_dir += PAGE_OFFSET >> PGDIR_SHIFT;
54
55 address = PAGE_OFFSET;
56 while (address < (unsigned long)high_memory) {
57 pg_table = (pte_t *) next_pgtable;
58 next_pgtable += PTRS_PER_PTE * sizeof(pte_t);
59 pgd_val(*pg_dir) = (unsigned long) pg_table;
60 pg_dir++;
61
62 /* now change pg_table to kernel virtual addresses */
63 for (i = 0; i < PTRS_PER_PTE; ++i, ++pg_table) {
64 pte_t pte = pfn_pte(virt_to_pfn((void *)address),
65 PAGE_INIT);
66 if (address >= (unsigned long) high_memory)
67 pte_val(pte) = 0;
68
69 set_pte(pg_table, pte);
70 address += PAGE_SIZE;
71 }
72 }
73
74 current->mm = NULL;
75 }
76
cf_tlb_miss(struct pt_regs * regs,int write,int dtlb,int extension_word)77 int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word)
78 {
79 unsigned long flags, mmuar, mmutr;
80 struct mm_struct *mm;
81 pgd_t *pgd;
82 p4d_t *p4d;
83 pud_t *pud;
84 pmd_t *pmd;
85 pte_t *pte = NULL;
86 int ret = -1;
87 int asid;
88
89 local_irq_save(flags);
90
91 mmuar = (dtlb) ? mmu_read(MMUAR) :
92 regs->pc + (extension_word * sizeof(long));
93
94 mm = (!user_mode(regs) && KMAPAREA(mmuar)) ? &init_mm : current->mm;
95 if (!mm)
96 goto out;
97
98 pgd = pgd_offset(mm, mmuar);
99 if (pgd_none(*pgd))
100 goto out;
101
102 p4d = p4d_offset(pgd, mmuar);
103 if (p4d_none(*p4d))
104 goto out;
105
106 pud = pud_offset(p4d, mmuar);
107 if (pud_none(*pud))
108 goto out;
109
110 pmd = pmd_offset(pud, mmuar);
111 if (pmd_none(*pmd))
112 goto out;
113
114 pte = (KMAPAREA(mmuar)) ? pte_offset_kernel(pmd, mmuar)
115 : pte_offset_map(pmd, mmuar);
116 if (!pte || pte_none(*pte) || !pte_present(*pte))
117 goto out;
118
119 if (write) {
120 if (!pte_write(*pte))
121 goto out;
122 set_pte(pte, pte_mkdirty(*pte));
123 }
124
125 set_pte(pte, pte_mkyoung(*pte));
126 asid = mm->context & 0xff;
127 if (!pte_dirty(*pte) && !KMAPAREA(mmuar))
128 set_pte(pte, pte_wrprotect(*pte));
129
130 mmutr = (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) | MMUTR_V;
131 if ((mmuar < TASK_UNMAPPED_BASE) || (mmuar >= TASK_SIZE))
132 mmutr |= (pte->pte & CF_PAGE_MMUTR_MASK) >> CF_PAGE_MMUTR_SHIFT;
133 mmu_write(MMUTR, mmutr);
134
135 mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) |
136 ((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X);
137
138 if (dtlb)
139 mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA);
140 else
141 mmu_write(MMUOR, MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA);
142 ret = 0;
143 out:
144 if (pte && !KMAPAREA(mmuar))
145 pte_unmap(pte);
146 local_irq_restore(flags);
147 return ret;
148 }
149
cf_bootmem_alloc(void)150 void __init cf_bootmem_alloc(void)
151 {
152 unsigned long memstart;
153
154 /* _rambase and _ramend will be naturally page aligned */
155 m68k_memory[0].addr = _rambase;
156 m68k_memory[0].size = _ramend - _rambase;
157
158 memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0,
159 MEMBLOCK_NONE);
160
161 /* compute total pages in system */
162 num_pages = PFN_DOWN(_ramend - _rambase);
163
164 /* page numbers */
165 memstart = PAGE_ALIGN(_ramstart);
166 min_low_pfn = PFN_DOWN(_rambase);
167 max_pfn = max_low_pfn = PFN_DOWN(_ramend);
168 high_memory = (void *)_ramend;
169
170 /* Reserve kernel text/data/bss */
171 memblock_reserve(_rambase, memstart - _rambase);
172
173 m68k_virt_to_node_shift = fls(_ramend - 1) - 6;
174 module_fixup(NULL, __start_fixup, __stop_fixup);
175
176 /* setup node data */
177 m68k_setup_node(0);
178 }
179
180 /*
181 * Initialize the context management stuff.
182 * The following was taken from arch/ppc/mmu_context.c
183 */
cf_mmu_context_init(void)184 void __init cf_mmu_context_init(void)
185 {
186 /*
187 * Some processors have too few contexts to reserve one for
188 * init_mm, and require using context 0 for a normal task.
189 * Other processors reserve the use of context zero for the kernel.
190 * This code assumes FIRST_CONTEXT < 32.
191 */
192 context_map[0] = (1 << FIRST_CONTEXT) - 1;
193 next_mmu_context = FIRST_CONTEXT;
194 atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1);
195 }
196
197 /*
198 * Steal a context from a task that has one at the moment.
199 * This isn't an LRU system, it just frees up each context in
200 * turn (sort-of pseudo-random replacement :). This would be the
201 * place to implement an LRU scheme if anyone was motivated to do it.
202 * -- paulus
203 */
steal_context(void)204 void steal_context(void)
205 {
206 struct mm_struct *mm;
207 /*
208 * free up context `next_mmu_context'
209 * if we shouldn't free context 0, don't...
210 */
211 if (next_mmu_context < FIRST_CONTEXT)
212 next_mmu_context = FIRST_CONTEXT;
213 mm = context_mm[next_mmu_context];
214 flush_tlb_mm(mm);
215 destroy_context(mm);
216 }
217
218 static const pgprot_t protection_map[16] = {
219 [VM_NONE] = PAGE_NONE,
220 [VM_READ] = __pgprot(CF_PAGE_VALID |
221 CF_PAGE_ACCESSED |
222 CF_PAGE_READABLE),
223 [VM_WRITE] = __pgprot(CF_PAGE_VALID |
224 CF_PAGE_ACCESSED |
225 CF_PAGE_WRITABLE),
226 [VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID |
227 CF_PAGE_ACCESSED |
228 CF_PAGE_READABLE |
229 CF_PAGE_WRITABLE),
230 [VM_EXEC] = __pgprot(CF_PAGE_VALID |
231 CF_PAGE_ACCESSED |
232 CF_PAGE_EXEC),
233 [VM_EXEC | VM_READ] = __pgprot(CF_PAGE_VALID |
234 CF_PAGE_ACCESSED |
235 CF_PAGE_READABLE |
236 CF_PAGE_EXEC),
237 [VM_EXEC | VM_WRITE] = __pgprot(CF_PAGE_VALID |
238 CF_PAGE_ACCESSED |
239 CF_PAGE_WRITABLE |
240 CF_PAGE_EXEC),
241 [VM_EXEC | VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID |
242 CF_PAGE_ACCESSED |
243 CF_PAGE_READABLE |
244 CF_PAGE_WRITABLE |
245 CF_PAGE_EXEC),
246 [VM_SHARED] = PAGE_NONE,
247 [VM_SHARED | VM_READ] = __pgprot(CF_PAGE_VALID |
248 CF_PAGE_ACCESSED |
249 CF_PAGE_READABLE),
250 [VM_SHARED | VM_WRITE] = PAGE_SHARED,
251 [VM_SHARED | VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID |
252 CF_PAGE_ACCESSED |
253 CF_PAGE_READABLE |
254 CF_PAGE_SHARED),
255 [VM_SHARED | VM_EXEC] = __pgprot(CF_PAGE_VALID |
256 CF_PAGE_ACCESSED |
257 CF_PAGE_EXEC),
258 [VM_SHARED | VM_EXEC | VM_READ] = __pgprot(CF_PAGE_VALID |
259 CF_PAGE_ACCESSED |
260 CF_PAGE_READABLE |
261 CF_PAGE_EXEC),
262 [VM_SHARED | VM_EXEC | VM_WRITE] = __pgprot(CF_PAGE_VALID |
263 CF_PAGE_ACCESSED |
264 CF_PAGE_SHARED |
265 CF_PAGE_EXEC),
266 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID |
267 CF_PAGE_ACCESSED |
268 CF_PAGE_READABLE |
269 CF_PAGE_SHARED |
270 CF_PAGE_EXEC)
271 };
272 DECLARE_VM_GET_PAGE_PROT
273