linux/arch/xtensa/mm/mmu.c
Johannes Weiner e5083a63b6 xtensa: nommu support
Add support for !CONFIG_MMU setups.

Signed-off-by: Johannes Weiner <jw@emlix.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
2009-04-02 23:41:50 -07:00

70 lines
1.6 KiB
C

/*
* xtensa mmu stuff
*
* Extracted from init.c
*/
#include <linux/percpu.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/cache.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
#include <asm/page.h>
DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
void __init paging_init(void)
{
memset(swapper_pg_dir, 0, PAGE_SIZE);
}
/*
* Flush the mmu and reset associated register to default values.
*/
void __init init_mmu(void)
{
/* Writing zeros to the <t>TLBCFG special registers ensure
* that valid values exist in the register. For existing
* PGSZID<w> fields, zero selects the first element of the
* page-size array. For nonexistent PGSZID<w> fields, zero is
* the best value to write. Also, when changing PGSZID<w>
* fields, the corresponding TLB must be flushed.
*/
set_itlbcfg_register(0);
set_dtlbcfg_register(0);
flush_tlb_all();
/* Set rasid register to a known value. */
set_rasid_register(ASID_USER_FIRST);
/* Set PTEVADDR special register to the start of the page
* table, which is in kernel mappable space (ie. not
* statically mapped). This register's value is undefined on
* reset.
*/
set_ptevaddr_register(PGTABLE_START);
}
struct kmem_cache *pgtable_cache __read_mostly;
static void pgd_ctor(void *addr)
{
pte_t *ptep = (pte_t *)addr;
int i;
for (i = 0; i < 1024; i++, ptep++)
pte_clear(NULL, 0, ptep);
}
void __init pgtable_cache_init(void)
{
pgtable_cache = kmem_cache_create("pgd",
PAGE_SIZE, PAGE_SIZE,
SLAB_HWCACHE_ALIGN,
pgd_ctor);
}