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/pgtable.h>
  25 #include <asm/machdep.h>
  26 #include <asm/io.h>
  27
  28 extern void mmu_emu_init (unsigned long bootmem_end);
  29
  30 const char bad_pmd_string[] = "Bad pmd in pte_alloc: %08lx\n";
  31
  32 extern unsigned long num_pages;
  33
  34 /* For the sun3 we try to follow the i386 paging_init() more closely */
  35 /* start_mem and end_mem have PAGE_OFFSET added already */
  36 /* now sets up tables using sun3 PTEs rather than i386 as before. --m */
  37 void __init paging_init(void)
  38 {
  39         pgd_t * pg_dir;
  40         pte_t * pg_table;
  41         int i;
  42         unsigned long address;
  43         unsigned long next_pgtable;
  44         unsigned long bootmem_end;
  45         unsigned long zones_size[MAX_NR_ZONES] = { 0, };
  46         unsigned long size;
  47
  48         empty_zero_page = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
  49         if (!empty_zero_page)
  50                 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
  51                       __func__, PAGE_SIZE, PAGE_SIZE);
  52
  53         address = PAGE_OFFSET;
  54         pg_dir = swapper_pg_dir;
  55         memset (swapper_pg_dir, 0, sizeof (swapper_pg_dir));
  56         memset (kernel_pg_dir,  0, sizeof (kernel_pg_dir));
  57
  58         size = num_pages * sizeof(pte_t);
  59         size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1);
  60
  61         next_pgtable = (unsigned long)memblock_alloc(size, PAGE_SIZE);
  62         if (!next_pgtable)
  63                 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
  64                       __func__, size, PAGE_SIZE);
  65         bootmem_end = (next_pgtable + size + PAGE_SIZE) & PAGE_MASK;
  66
  67         /* Map whole memory from PAGE_OFFSET (0x0E000000) */
  68         pg_dir += PAGE_OFFSET >> PGDIR_SHIFT;
  69
  70         while (address < (unsigned long)high_memory) {
  71                 pg_table = (pte_t *) __pa (next_pgtable);
  72                 next_pgtable += PTRS_PER_PTE * sizeof (pte_t);
  73                 pgd_val(*pg_dir) = (unsigned long) pg_table;
  74                 pg_dir++;
  75
  76                 /* now change pg_table to kernel virtual addresses */
  77                 pg_table = (pte_t *) __va ((unsigned long) pg_table);
  78                 for (i=0; i<PTRS_PER_PTE; ++i, ++pg_table) {
  79                         pte_t pte = pfn_pte(virt_to_pfn(address), PAGE_INIT);
  80                         if (address >= (unsigned long)high_memory)
  81                                 pte_val (pte) = 0;
  82                         set_pte (pg_table, pte);
  83                         address += PAGE_SIZE;
  84                 }
  85         }
  86
  87         mmu_emu_init(bootmem_end);
  88
  89         current->mm = NULL;
  90
  91         /* memory sizing is a hack stolen from motorola.c..  hope it works for us */
  92         zones_size[ZONE_DMA] = ((unsigned long)high_memory - PAGE_OFFSET) >> PAGE_SHIFT;
  93
  94         /* I really wish I knew why the following change made things better...  -- Sam */
  95 /*      free_area_init(zones_size); */
  96         free_area_init_node(0, zones_size,
  97                             (__pa(PAGE_OFFSET) >> PAGE_SHIFT) + 1, NULL);
  98
  99
 100 }
 101
 102