diff options
Diffstat (limited to 'arch/x86/mm/init_32.c')
| -rw-r--r-- | arch/x86/mm/init_32.c | 65 |
1 files changed, 60 insertions, 5 deletions
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c index d37f29376b0..9b5f7d7049d 100644 --- a/arch/x86/mm/init_32.c +++ b/arch/x86/mm/init_32.c @@ -194,11 +194,30 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base, pgd_t *pgd; pmd_t *pmd; pte_t *pte; - unsigned pages_2m = 0, pages_4k = 0; + unsigned pages_2m, pages_4k; + int mapping_iter; + + /* + * First iteration will setup identity mapping using large/small pages + * based on use_pse, with other attributes same as set by + * the early code in head_32.S + * + * Second iteration will setup the appropriate attributes (NX, GLOBAL..) + * as desired for the kernel identity mapping. + * + * This two pass mechanism conforms to the TLB app note which says: + * + * "Software should not write to a paging-structure entry in a way + * that would change, for any linear address, both the page size + * and either the page frame or attributes." + */ + mapping_iter = 1; if (!cpu_has_pse) use_pse = 0; +repeat: + pages_2m = pages_4k = 0; pfn = start_pfn; pgd_idx = pgd_index((pfn<<PAGE_SHIFT) + PAGE_OFFSET); pgd = pgd_base + pgd_idx; @@ -224,6 +243,13 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base, if (use_pse) { unsigned int addr2; pgprot_t prot = PAGE_KERNEL_LARGE; + /* + * first pass will use the same initial + * identity mapping attribute + _PAGE_PSE. + */ + pgprot_t init_prot = + __pgprot(PTE_IDENT_ATTR | + _PAGE_PSE); addr2 = (pfn + PTRS_PER_PTE-1) * PAGE_SIZE + PAGE_OFFSET + PAGE_SIZE-1; @@ -233,7 +259,10 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base, prot = PAGE_KERNEL_LARGE_EXEC; pages_2m++; - set_pmd(pmd, pfn_pmd(pfn, prot)); + if (mapping_iter == 1) + set_pmd(pmd, pfn_pmd(pfn, init_prot)); + else + set_pmd(pmd, pfn_pmd(pfn, prot)); pfn += PTRS_PER_PTE; continue; @@ -245,17 +274,43 @@ static void __init kernel_physical_mapping_init(pgd_t *pgd_base, for (; pte_ofs < PTRS_PER_PTE && pfn < end_pfn; pte++, pfn++, pte_ofs++, addr += PAGE_SIZE) { pgprot_t prot = PAGE_KERNEL; + /* + * first pass will use the same initial + * identity mapping attribute. + */ + pgprot_t init_prot = __pgprot(PTE_IDENT_ATTR); if (is_kernel_text(addr)) prot = PAGE_KERNEL_EXEC; pages_4k++; - set_pte(pte, pfn_pte(pfn, prot)); + if (mapping_iter == 1) + set_pte(pte, pfn_pte(pfn, init_prot)); + else + set_pte(pte, pfn_pte(pfn, prot)); } } } - update_page_count(PG_LEVEL_2M, pages_2m); - update_page_count(PG_LEVEL_4K, pages_4k); + if (mapping_iter == 1) { + /* + * update direct mapping page count only in the first + * iteration. + */ + update_page_count(PG_LEVEL_2M, pages_2m); + update_page_count(PG_LEVEL_4K, pages_4k); + + /* + * local global flush tlb, which will flush the previous + * mappings present in both small and large page TLB's. + */ + __flush_tlb_all(); + + /* + * Second iteration will set the actual desired PTE attributes. + */ + mapping_iter = 2; + goto repeat; + } } /* |