diff options
| author | Matt Fleming <matt@console-pimps.org> | 2009-12-13 14:38:50 +0000 |
|---|---|---|
| committer | Paul Mundt <lethal@linux-sh.org> | 2009-12-17 14:31:20 +0900 |
| commit | 5d9b4b19f118abfb75e352841f7bf74580d7e427 (patch) | |
| tree | 5b9d0ec51bd12165d842d1d8a208e7568971757b /arch/sh/mm/init.c | |
| parent | b73c806341cfc7492ede6a2ce713cb579547d0ab (diff) | |
sh: Definitions for 3-level page table layout
If using 64-bit PTEs and 4K pages then each page table has 512 entries
(as opposed to 1024 entries with 32-bit PTEs). Unlike MIPS, SH follows
the convention that all structures in the page table (pgd_t, pmd_t,
pgprot_t, etc) must be the same size. Therefore, 64-bit PTEs require
64-bit PGD entries, etc. Using 2-levels of page tables and 64-bit PTEs
it is only possible to map 1GB of virtual address space.
In order to map all 4GB of virtual address space we need to adopt a
3-level page table layout. This actually works out better for
CONFIG_SUPERH32 because we only waste 2 PGD entries on the P1 and P2
areas (which are untranslated) instead of 256.
Signed-off-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/mm/init.c')
| -rw-r--r-- | arch/sh/mm/init.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c index 432acd07e76..761910d142f 100644 --- a/arch/sh/mm/init.c +++ b/arch/sh/mm/init.c @@ -120,7 +120,13 @@ void __init page_table_range_init(unsigned long start, unsigned long end, for ( ; (i < PTRS_PER_PGD) && (vaddr != end); pgd++, i++) { pud = (pud_t *)pgd; for ( ; (j < PTRS_PER_PUD) && (vaddr != end); pud++, j++) { +#ifdef __PAGETABLE_PMD_FOLDED pmd = (pmd_t *)pud; +#else + pmd = (pmd_t *)alloc_bootmem_low_pages(PAGE_SIZE); + pud_populate(&init_mm, pud, pmd); + pmd += k; +#endif for (; (k < PTRS_PER_PMD) && (vaddr != end); pmd++, k++) { if (pmd_none(*pmd)) { pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE); |