1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/arch/m68k/mm/sun3mmu.c
4 *
5 * Implementations of mm routines specific to the sun3 MMU.
6 *
7 * Moved here 8/20/1999 Sam Creasey
8 *
9 */
10
11 #include <linux/signal.h>
12 #include <linux/sched.h>
13 #include <linux/mm.h>
14 #include <linux/swap.h>
15 #include <linux/kernel.h>
16 #include <linux/string.h>
17 #include <linux/types.h>
18 #include <linux/init.h>
19 #include <linux/memblock.h>
20
21 #include <asm/setup.h>
22 #include <linux/uaccess.h>
23 #include <asm/page.h>
24 #include <asm/machdep.h>
25 #include <asm/io.h>
26
27 #include "../sun3/sun3.h"
28
29 const char bad_pmd_string[] = "Bad pmd in pte_alloc: %08lx\n";
30
31 extern unsigned long num_pages;
32
33 /* For the sun3 we try to follow the i386 paging_init() more closely */
34 /* start_mem and end_mem have PAGE_OFFSET added already */
35 /* now sets up tables using sun3 PTEs rather than i386 as before. --m */
36 void __init paging_init(void)
37 {
38 pgd_t * pg_dir;
39 pte_t * pg_table;
40 int i;
41 unsigned long address;
42 unsigned long next_pgtable;
43 unsigned long bootmem_end;
44 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0, };
45 unsigned long size;
46
47 empty_zero_page = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
48 if (!empty_zero_page)
49 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
50 __func__, PAGE_SIZE, PAGE_SIZE);
51
52 address = PAGE_OFFSET;
53 pg_dir = swapper_pg_dir;
54 memset (swapper_pg_dir, 0, sizeof (swapper_pg_dir));
55 memset (kernel_pg_dir, 0, sizeof (kernel_pg_dir));
56
57 size = num_pages * sizeof(pte_t);
58 size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1);
59
60 next_pgtable = (unsigned long)memblock_alloc(size, PAGE_SIZE);
61 if (!next_pgtable)
62 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
63 __func__, size, PAGE_SIZE);
64 bootmem_end = (next_pgtable + size + PAGE_SIZE) & PAGE_MASK;
65
66 /* Map whole memory from PAGE_OFFSET (0x0E000000) */
67 pg_dir += PAGE_OFFSET >> PGDIR_SHIFT;
68
69 while (address < (unsigned long)high_memory) {
70 pg_table = (pte_t *) __pa (next_pgtable);
71 next_pgtable += PTRS_PER_PTE * sizeof (pte_t);
72 pgd_val(*pg_dir) = (unsigned long) pg_table;
73 pg_dir++;
74
75 /* now change pg_table to kernel virtual addresses */
76 pg_table = (pte_t *) __va ((unsigned long) pg_table);
77 for (i=0; i<PTRS_PER_PTE; ++i, ++pg_table) {
78 pte_t pte = pfn_pte(virt_to_pfn((void *)address), PAGE_INIT);
79 if (address >= (unsigned long)high_memory)
80 pte_val (pte) = 0;
81 set_pte (pg_table, pte);
82 address += PAGE_SIZE;
83 }
84 }
85
86 mmu_emu_init(bootmem_end);
87
88 current->mm = NULL;
89
90 /* memory sizing is a hack stolen from motorola.c.. hope it works for us */
91 max_zone_pfn[ZONE_DMA] = ((unsigned long)high_memory) >> PAGE_SHIFT;
92
93 /* I really wish I knew why the following change made things better... -- Sam */
94 free_area_init(max_zone_pfn);
95
96
97 }
98
99 static const pgprot_t protection_map[16] = {
100 [VM_NONE] = PAGE_NONE,
101 [VM_READ] = PAGE_READONLY,
102 [VM_WRITE] = PAGE_COPY,
103 [VM_WRITE | VM_READ] = PAGE_COPY,
104 [VM_EXEC] = PAGE_READONLY,
105 [VM_EXEC | VM_READ] = PAGE_READONLY,
106 [VM_EXEC | VM_WRITE] = PAGE_COPY,
107 [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY,
108 [VM_SHARED] = PAGE_NONE,
109 [VM_SHARED | VM_READ] = PAGE_READONLY,
110 [VM_SHARED | VM_WRITE] = PAGE_SHARED,
111 [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED,
112 [VM_SHARED | VM_EXEC] = PAGE_READONLY,
113 [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY,
114 [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED,
115 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED
116 };
117 DECLARE_VM_GET_PAGE_PROT
118
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