sun3mmu.c

  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
 29const char bad_pmd_string[] = "Bad pmd in pte_alloc: %08lx\n";
 30
 31extern 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 */
 36void __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_or_panic(PAGE_SIZE, PAGE_SIZE);
 48
 49	address = PAGE_OFFSET;
 50	pg_dir = swapper_pg_dir;
 51	memset (swapper_pg_dir, 0, sizeof (swapper_pg_dir));
 52	memset (kernel_pg_dir,  0, sizeof (kernel_pg_dir));
 53
 54	size = num_pages * sizeof(pte_t);
 55	size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1);
 56
 57	next_pgtable = (unsigned long)memblock_alloc_or_panic(size, PAGE_SIZE);
 58	bootmem_end = (next_pgtable + size + PAGE_SIZE) & PAGE_MASK;
 59
 60	/* Map whole memory from PAGE_OFFSET (0x0E000000) */
 61	pg_dir += PAGE_OFFSET >> PGDIR_SHIFT;
 62
 63	while (address < (unsigned long)high_memory) {
 64		pg_table = (pte_t *) __pa (next_pgtable);
 65		next_pgtable += PTRS_PER_PTE * sizeof (pte_t);
 66		pgd_val(*pg_dir) = (unsigned long) pg_table;
 67		pg_dir++;
 68
 69		/* now change pg_table to kernel virtual addresses */
 70		pg_table = (pte_t *) __va ((unsigned long) pg_table);
 71		for (i=0; i<PTRS_PER_PTE; ++i, ++pg_table) {
 72			pte_t pte = pfn_pte(virt_to_pfn((void *)address), PAGE_INIT);
 73			if (address >= (unsigned long)high_memory)
 74				pte_val (pte) = 0;
 75			set_pte (pg_table, pte);
 76			address += PAGE_SIZE;
 77		}
 78	}
 79
 80	mmu_emu_init(bootmem_end);
 81
 82	current->mm = NULL;
 83
 84	/* memory sizing is a hack stolen from motorola.c..  hope it works for us */
 85	max_zone_pfn[ZONE_DMA] = ((unsigned long)high_memory) >> PAGE_SHIFT;
 86
 87	/* I really wish I knew why the following change made things better...  -- Sam */
 88	free_area_init(max_zone_pfn);
 89
 90
 91}
 92
 93static const pgprot_t protection_map[16] = {
 94	[VM_NONE]					= PAGE_NONE,
 95	[VM_READ]					= PAGE_READONLY,
 96	[VM_WRITE]					= PAGE_COPY,
 97	[VM_WRITE | VM_READ]				= PAGE_COPY,
 98	[VM_EXEC]					= PAGE_READONLY,
 99	[VM_EXEC | VM_READ]				= PAGE_READONLY,
100	[VM_EXEC | VM_WRITE]				= PAGE_COPY,
101	[VM_EXEC | VM_WRITE | VM_READ]			= PAGE_COPY,
102	[VM_SHARED]					= PAGE_NONE,
103	[VM_SHARED | VM_READ]				= PAGE_READONLY,
104	[VM_SHARED | VM_WRITE]				= PAGE_SHARED,
105	[VM_SHARED | VM_WRITE | VM_READ]		= PAGE_SHARED,
106	[VM_SHARED | VM_EXEC]				= PAGE_READONLY,
107	[VM_SHARED | VM_EXEC | VM_READ]			= PAGE_READONLY,
108	[VM_SHARED | VM_EXEC | VM_WRITE]		= PAGE_SHARED,
109	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= PAGE_SHARED
110};
111DECLARE_VM_GET_PAGE_PROT