linux/arch/xtensa/mm/mmu.c
Max Filippov dec7305d9f xtensa: allow fixmap and kmap span more than one page table
To support aliasing cache both kmap region sizes are multiplied by the
number of data cache colors. After that expansion page tables that cover
kmap regions may become larger than one page. Correctly allocate and
initialize page tables in this case.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2014-08-14 11:59:18 +04:00

110 lines
2.8 KiB
C

/*
* 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);
}