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285 lines
6.3 KiB
285 lines
6.3 KiB
/*
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* linux/arch/m68k/motorola.c
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*
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* Routines specific to the Motorola MMU, originally from:
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* linux/arch/m68k/init.c
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* which are Copyright (C) 1995 Hamish Macdonald
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*
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* Moved 8/20/1999 Sam Creasey
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*/
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#include <linux/config.h>
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#include <linux/module.h>
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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/bootmem.h>
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#include <asm/setup.h>
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#include <asm/uaccess.h>
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#include <asm/page.h>
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#include <asm/pgalloc.h>
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#include <asm/system.h>
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#include <asm/machdep.h>
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#include <asm/io.h>
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#include <asm/dma.h>
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#ifdef CONFIG_ATARI
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#include <asm/atari_stram.h>
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#endif
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#undef DEBUG
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#ifndef mm_cachebits
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/*
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* Bits to add to page descriptors for "normal" caching mode.
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* For 68020/030 this is 0.
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* For 68040, this is _PAGE_CACHE040 (cachable, copyback)
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*/
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unsigned long mm_cachebits;
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EXPORT_SYMBOL(mm_cachebits);
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#endif
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static pte_t * __init kernel_page_table(void)
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{
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pte_t *ptablep;
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ptablep = (pte_t *)alloc_bootmem_low_pages(PAGE_SIZE);
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clear_page(ptablep);
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__flush_page_to_ram(ptablep);
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flush_tlb_kernel_page(ptablep);
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nocache_page(ptablep);
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return ptablep;
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}
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static pmd_t *last_pgtable __initdata = NULL;
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pmd_t *zero_pgtable __initdata = NULL;
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static pmd_t * __init kernel_ptr_table(void)
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{
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if (!last_pgtable) {
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unsigned long pmd, last;
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int i;
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/* Find the last ptr table that was used in head.S and
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* reuse the remaining space in that page for further
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* ptr tables.
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*/
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last = (unsigned long)kernel_pg_dir;
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for (i = 0; i < PTRS_PER_PGD; i++) {
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if (!pgd_present(kernel_pg_dir[i]))
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continue;
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pmd = __pgd_page(kernel_pg_dir[i]);
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if (pmd > last)
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last = pmd;
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}
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last_pgtable = (pmd_t *)last;
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#ifdef DEBUG
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printk("kernel_ptr_init: %p\n", last_pgtable);
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#endif
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}
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last_pgtable += PTRS_PER_PMD;
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if (((unsigned long)last_pgtable & ~PAGE_MASK) == 0) {
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last_pgtable = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE);
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clear_page(last_pgtable);
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__flush_page_to_ram(last_pgtable);
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flush_tlb_kernel_page(last_pgtable);
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nocache_page(last_pgtable);
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}
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return last_pgtable;
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}
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static unsigned long __init
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map_chunk (unsigned long addr, long size)
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{
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#define PTRTREESIZE (256*1024)
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#define ROOTTREESIZE (32*1024*1024)
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static unsigned long virtaddr = PAGE_OFFSET;
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unsigned long physaddr;
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pgd_t *pgd_dir;
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pmd_t *pmd_dir;
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pte_t *pte_dir;
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physaddr = (addr | m68k_supervisor_cachemode |
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_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_DIRTY);
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if (CPU_IS_040_OR_060)
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physaddr |= _PAGE_GLOBAL040;
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while (size > 0) {
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#ifdef DEBUG
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if (!(virtaddr & (PTRTREESIZE-1)))
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printk ("\npa=%#lx va=%#lx ", physaddr & PAGE_MASK,
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virtaddr);
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#endif
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pgd_dir = pgd_offset_k(virtaddr);
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if (virtaddr && CPU_IS_020_OR_030) {
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if (!(virtaddr & (ROOTTREESIZE-1)) &&
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size >= ROOTTREESIZE) {
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#ifdef DEBUG
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printk ("[very early term]");
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#endif
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pgd_val(*pgd_dir) = physaddr;
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size -= ROOTTREESIZE;
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virtaddr += ROOTTREESIZE;
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physaddr += ROOTTREESIZE;
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continue;
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}
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}
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if (!pgd_present(*pgd_dir)) {
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pmd_dir = kernel_ptr_table();
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#ifdef DEBUG
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printk ("[new pointer %p]", pmd_dir);
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#endif
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pgd_set(pgd_dir, pmd_dir);
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} else
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pmd_dir = pmd_offset(pgd_dir, virtaddr);
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if (CPU_IS_020_OR_030) {
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if (virtaddr) {
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#ifdef DEBUG
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printk ("[early term]");
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#endif
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pmd_dir->pmd[(virtaddr/PTRTREESIZE) & 15] = physaddr;
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physaddr += PTRTREESIZE;
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} else {
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int i;
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#ifdef DEBUG
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printk ("[zero map]");
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#endif
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zero_pgtable = kernel_ptr_table();
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pte_dir = (pte_t *)zero_pgtable;
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pmd_dir->pmd[0] = virt_to_phys(pte_dir) |
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_PAGE_TABLE | _PAGE_ACCESSED;
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pte_val(*pte_dir++) = 0;
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physaddr += PAGE_SIZE;
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for (i = 1; i < 64; physaddr += PAGE_SIZE, i++)
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pte_val(*pte_dir++) = physaddr;
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}
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size -= PTRTREESIZE;
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virtaddr += PTRTREESIZE;
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} else {
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if (!pmd_present(*pmd_dir)) {
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#ifdef DEBUG
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printk ("[new table]");
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#endif
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pte_dir = kernel_page_table();
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pmd_set(pmd_dir, pte_dir);
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}
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pte_dir = pte_offset_kernel(pmd_dir, virtaddr);
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if (virtaddr) {
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if (!pte_present(*pte_dir))
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pte_val(*pte_dir) = physaddr;
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} else
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pte_val(*pte_dir) = 0;
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size -= PAGE_SIZE;
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virtaddr += PAGE_SIZE;
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physaddr += PAGE_SIZE;
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}
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}
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#ifdef DEBUG
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printk("\n");
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#endif
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return virtaddr;
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}
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/*
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* paging_init() continues the virtual memory environment setup which
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* was begun by the code in arch/head.S.
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*/
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void __init paging_init(void)
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{
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int chunk;
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unsigned long mem_avail = 0;
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unsigned long zones_size[3] = { 0, };
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#ifdef DEBUG
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{
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extern unsigned long availmem;
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printk ("start of paging_init (%p, %lx, %lx, %lx)\n",
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kernel_pg_dir, availmem, start_mem, end_mem);
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}
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#endif
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/* Fix the cache mode in the page descriptors for the 680[46]0. */
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if (CPU_IS_040_OR_060) {
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int i;
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#ifndef mm_cachebits
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mm_cachebits = _PAGE_CACHE040;
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#endif
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for (i = 0; i < 16; i++)
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pgprot_val(protection_map[i]) |= _PAGE_CACHE040;
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}
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/*
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* Map the physical memory available into the kernel virtual
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* address space. It may allocate some memory for page
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* tables and thus modify availmem.
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*/
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for (chunk = 0; chunk < m68k_num_memory; chunk++) {
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mem_avail = map_chunk (m68k_memory[chunk].addr,
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m68k_memory[chunk].size);
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}
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flush_tlb_all();
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#ifdef DEBUG
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printk ("memory available is %ldKB\n", mem_avail >> 10);
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printk ("start_mem is %#lx\nvirtual_end is %#lx\n",
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start_mem, end_mem);
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#endif
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/*
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* initialize the bad page table and bad page to point
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* to a couple of allocated pages
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*/
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empty_zero_page = alloc_bootmem_pages(PAGE_SIZE);
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memset(empty_zero_page, 0, PAGE_SIZE);
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/*
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* Set up SFC/DFC registers
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*/
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set_fs(KERNEL_DS);
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#ifdef DEBUG
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printk ("before free_area_init\n");
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#endif
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zones_size[0] = (mach_max_dma_address < (unsigned long)high_memory ?
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(mach_max_dma_address+1) : (unsigned long)high_memory);
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zones_size[1] = (unsigned long)high_memory - zones_size[0];
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zones_size[0] = (zones_size[0] - PAGE_OFFSET) >> PAGE_SHIFT;
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zones_size[1] >>= PAGE_SHIFT;
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free_area_init(zones_size);
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}
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extern char __init_begin, __init_end;
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void free_initmem(void)
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{
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unsigned long addr;
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addr = (unsigned long)&__init_begin;
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for (; addr < (unsigned long)&__init_end; addr += PAGE_SIZE) {
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virt_to_page(addr)->flags &= ~(1 << PG_reserved);
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set_page_count(virt_to_page(addr), 1);
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free_page(addr);
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totalram_pages++;
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}
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}
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