arch/m68k/mm/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 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 */
  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 }