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 extern void mmu_emu_init (unsigned long bootmem_end);
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 */
paging_init(void)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(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