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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/m68k/mm/sun3mmu.c
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// SPDX-License-Identifier: GPL-2.0

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/*

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 * linux/arch/m68k/mm/sun3mmu.c

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 *

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 * Implementations of mm routines specific to the sun3 MMU.

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 *

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 * Moved here 8/20/1999 Sam Creasey

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 *

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 */

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#include <linux/signal.h>

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#include <linux/sched.h>

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#include <linux/mm.h>

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#include <linux/swap.h>

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#include <linux/kernel.h>

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#include <linux/string.h>

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#include <linux/types.h>

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#include <linux/init.h>

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#include <linux/memblock.h>

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#include <asm/setup.h>

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#include <linux/uaccess.h>

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#include <asm/page.h>

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#include <asm/machdep.h>

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#include <asm/io.h>

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#include "../sun3/sun3.h"

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const char bad_pmd_string[] = "Bad pmd in pte_alloc: %08lx\n";

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extern unsigned long num_pages;

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/* For the sun3 we try to follow the i386 paging_init() more closely */

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/* start_mem and end_mem have PAGE_OFFSET added already */

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/* now sets up tables using sun3 PTEs rather than i386 as before. --m */

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void __init paging_init(void)

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{

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	pgd_t * pg_dir;

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	pte_t * pg_table;

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	int i;

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	unsigned long address;

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	unsigned long next_pgtable;

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	unsigned long bootmem_end;

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	unsigned long size;

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	empty_zero_page = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE);

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	address = PAGE_OFFSET;

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	pg_dir = swapper_pg_dir;

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	memset (swapper_pg_dir, 0, sizeof (swapper_pg_dir));

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	memset (kernel_pg_dir,  0, sizeof (kernel_pg_dir));

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	size = num_pages * sizeof(pte_t);

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	size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1);

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	next_pgtable = (unsigned long)memblock_alloc_or_panic(size, PAGE_SIZE);

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	bootmem_end = (next_pgtable + size + PAGE_SIZE) & PAGE_MASK;

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	/* Map whole memory from PAGE_OFFSET (0x0E000000) */

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	pg_dir += PAGE_OFFSET >> PGDIR_SHIFT;

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	while (address < (unsigned long)high_memory) {

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		pg_table = (pte_t *) __pa (next_pgtable);

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		next_pgtable += PTRS_PER_PTE * sizeof (pte_t);

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		pgd_val(*pg_dir) = (unsigned long) pg_table;

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		pg_dir++;

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		/* now change pg_table to kernel virtual addresses */

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		pg_table = (pte_t *) __va ((unsigned long) pg_table);

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		for (i=0; i<PTRS_PER_PTE; ++i, ++pg_table) {

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			pte_t pte = pfn_pte(virt_to_pfn((void *)address), PAGE_INIT);

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			if (address >= (unsigned long)high_memory)

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				pte_val (pte) = 0;

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			set_pte (pg_table, pte);

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			address += PAGE_SIZE;

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		}

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	}

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	mmu_emu_init(bootmem_end);

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	current->mm = NULL;

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}

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static const pgprot_t protection_map[16] = {

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	[VM_NONE]					= PAGE_NONE,

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	[VM_READ]					= PAGE_READONLY,

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	[VM_WRITE]					= PAGE_COPY,

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	[VM_WRITE | VM_READ]				= PAGE_COPY,

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	[VM_EXEC]					= PAGE_READONLY,

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	[VM_EXEC | VM_READ]				= PAGE_READONLY,

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	[VM_EXEC | VM_WRITE]				= PAGE_COPY,

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	[VM_EXEC | VM_WRITE | VM_READ]			= PAGE_COPY,

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	[VM_SHARED]					= PAGE_NONE,

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	[VM_SHARED | VM_READ]				= PAGE_READONLY,

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	[VM_SHARED | VM_WRITE]				= PAGE_SHARED,

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	[VM_SHARED | VM_WRITE | VM_READ]		= PAGE_SHARED,

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	[VM_SHARED | VM_EXEC]				= PAGE_READONLY,

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	[VM_SHARED | VM_EXEC | VM_READ]			= PAGE_READONLY,

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	[VM_SHARED | VM_EXEC | VM_WRITE]		= PAGE_SHARED,

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	[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ]	= PAGE_SHARED

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};

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DECLARE_VM_GET_PAGE_PROT

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