linux/arch/m68k/mm/sun3mmu.c
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   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
  27extern void mmu_emu_init (unsigned long bootmem_end);
  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(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