diff options
Diffstat (limited to 'kernel/arch/xtensa/mm/mmu.c')
| -rw-r--r-- | kernel/arch/xtensa/mm/mmu.c | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/kernel/arch/xtensa/mm/mmu.c b/kernel/arch/xtensa/mm/mmu.c new file mode 100644 index 000000000..abe4513eb --- /dev/null +++ b/kernel/arch/xtensa/mm/mmu.c @@ -0,0 +1,110 @@ +/* + * 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); +} |