LXR linux/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
  17void __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 */
  25void __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_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
  50struct kmem_cache *pgtable_cache __read_mostly;
  51
  52static 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
  62void __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}
  69