mmu.c
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/*
* xtensa mmu stuff
*
* Extracted from init.c
*/
#include <linux/bootmem.h>
#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>
#include <asm/initialize_mmu.h>
#include <asm/io.h>
#if defined(CONFIG_HIGHMEM)
static void * __init init_pmd(unsigned long vaddr, unsigned long n_pages)
{
pgd_t *pgd = pgd_offset_k(vaddr);
pmd_t *pmd = pmd_offset(pgd, vaddr);
pte_t *pte;
unsigned long i;
n_pages = ALIGN(n_pages, PTRS_PER_PTE);
pr_debug("%s: vaddr: 0x%08lx, n_pages: %ld\n",
__func__, vaddr, n_pages);
pte = alloc_bootmem_low_pages(n_pages * sizeof(pte_t));
for (i = 0; i < n_pages; ++i)
pte_clear(NULL, 0, pte + i);
for (i = 0; i < n_pages; i += PTRS_PER_PTE, ++pmd) {
pte_t *cur_pte = pte + i;
BUG_ON(!pmd_none(*pmd));
set_pmd(pmd, __pmd(((unsigned long)cur_pte) & PAGE_MASK));
BUG_ON(cur_pte != pte_offset_kernel(pmd, 0));
pr_debug("%s: pmd: 0x%p, pte: 0x%p\n",
__func__, pmd, cur_pte);
}
return pte;
}
static void __init fixedrange_init(void)
{
init_pmd(__fix_to_virt(0), __end_of_fixed_addresses);
}
#endif
void __init paging_init(void)
{
memset(swapper_pg_dir, 0, PAGE_SIZE);
#ifdef CONFIG_HIGHMEM
fixedrange_init();
pkmap_page_table = init_pmd(PKMAP_BASE, LAST_PKMAP);
kmap_init();
#endif
}
/*
* Flush the mmu and reset associated register to default values.
*/
void init_mmu(void)
{
#if !(XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY)
/*
* Writing zeros to the instruction and data 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);
#endif
#if XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY && defined(CONFIG_OF)
/*
* Update the IO area mapping in case xtensa_kio_paddr has changed
*/
write_dtlb_entry(__pte(xtensa_kio_paddr + CA_WRITEBACK),
XCHAL_KIO_CACHED_VADDR + 6);
write_itlb_entry(__pte(xtensa_kio_paddr + CA_WRITEBACK),
XCHAL_KIO_CACHED_VADDR + 6);
write_dtlb_entry(__pte(xtensa_kio_paddr + CA_BYPASS),
XCHAL_KIO_BYPASS_VADDR + 6);
write_itlb_entry(__pte(xtensa_kio_paddr + CA_BYPASS),
XCHAL_KIO_BYPASS_VADDR + 6);
#endif
local_flush_tlb_all();
/* Set rasid register to a known value. */
set_rasid_register(ASID_INSERT(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);
}