arch/xtensa/mm/mmu.c

   1 /*
   2  * xtensa mmu stuff
   3  *
   4  * Extracted from init.c
   5  */
   6 #include <linux/percpu.h>
   7 #include <linux/init.h>
   8 #include <linux/string.h>
   9 #include <linux/slab.h>
  10 #include <linux/cache.h>
  11
  12 #include <asm/tlb.h>
  13 #include <asm/tlbflush.h>
  14 #include <asm/mmu_context.h>
  15 #include <asm/page.h>
  16
  17 void __init paging_init(void)
  18 {
  19         memset(swapper_pg_dir, 0, PAGE_SIZE);
  20 }
  21
  22 /*
  23  * Flush the mmu and reset associated register to default values.
  24  */
  25 void __init init_mmu(void)
  26 {
  27         /* Writing zeros to the <t>TLBCFG special registers ensure
  28          * that valid values exist in the register.  For existing
  29          * PGSZID<w> fields, zero selects the first element of the
  30          * page-size array.  For nonexistent PGSZID<w> fields, zero is
  31          * the best value to write.  Also, when changing PGSZID<w>
  32          * fields, the corresponding TLB must be flushed.
  33          */
  34         set_itlbcfg_register(0);
  35         set_dtlbcfg_register(0);
  36         flush_tlb_all();
  37
  38         /* Set rasid register to a known value. */
  39
  40         set_rasid_register(ASID_INSERT(ASID_USER_FIRST));
  41
  42         /* Set PTEVADDR special register to the start of the page
  43          * table, which is in kernel mappable space (ie. not
  44          * statically mapped).  This register's value is undefined on
  45          * reset.
  46          */
  47         set_ptevaddr_register(PGTABLE_START);
  48 }
  49
  50 struct kmem_cache *pgtable_cache __read_mostly;
  51
  52 static void pgd_ctor(void *addr)
  53 {
  54         pte_t *ptep = (pte_t *)addr;
  55         int i;
  56
  57         for (i = 0; i < 1024; i++, ptep++)
  58                 pte_clear(NULL, 0, ptep);
  59
  60 }
  61
  62 void __init pgtable_cache_init(void)
  63 {
  64         pgtable_cache = kmem_cache_create("pgd",
  65                         PAGE_SIZE, PAGE_SIZE,
  66                         SLAB_HWCACHE_ALIGN,
  67                         pgd_ctor);
  68 }