diff options
| -rw-r--r-- | arch/x86/mm/init_64.c | 149 |
1 files changed, 61 insertions, 88 deletions
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 6116ff0..8c7eae4 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -270,10 +270,9 @@ static __ref void unmap_low_page(void *adr) early_iounmap(adr, PAGE_SIZE); } -static int physical_mapping_iter; - static unsigned long __meminit -phys_pte_init(pte_t *pte_page, unsigned long addr, unsigned long end) +phys_pte_init(pte_t *pte_page, unsigned long addr, unsigned long end, + pgprot_t prot) { unsigned pages = 0; unsigned long last_map_addr = end; @@ -291,35 +290,40 @@ phys_pte_init(pte_t *pte_page, unsigned long addr, unsigned long end) break; } + /* + * We will re-use the existing mapping. + * Xen for example has some special requirements, like mapping + * pagetable pages as RO. So assume someone who pre-setup + * these mappings are more intelligent. + */ if (pte_val(*pte)) - goto repeat_set_pte; + continue; if (0) printk(" pte=%p addr=%lx pte=%016lx\n", pte, addr, pfn_pte(addr >> PAGE_SHIFT, PAGE_KERNEL).pte); pages++; -repeat_set_pte: - set_pte(pte, pfn_pte(addr >> PAGE_SHIFT, PAGE_KERNEL)); + set_pte(pte, pfn_pte(addr >> PAGE_SHIFT, prot)); last_map_addr = (addr & PAGE_MASK) + PAGE_SIZE; } - if (physical_mapping_iter == 1) - update_page_count(PG_LEVEL_4K, pages); + update_page_count(PG_LEVEL_4K, pages); return last_map_addr; } static unsigned long __meminit -phys_pte_update(pmd_t *pmd, unsigned long address, unsigned long end) +phys_pte_update(pmd_t *pmd, unsigned long address, unsigned long end, + pgprot_t prot) { pte_t *pte = (pte_t *)pmd_page_vaddr(*pmd); - return phys_pte_init(pte, address, end); + return phys_pte_init(pte, address, end, prot); } static unsigned long __meminit phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end, - unsigned long page_size_mask) + unsigned long page_size_mask, pgprot_t prot) { unsigned long pages = 0; unsigned long last_map_addr = end; @@ -330,6 +334,7 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end, unsigned long pte_phys; pmd_t *pmd = pmd_page + pmd_index(address); pte_t *pte; + pgprot_t new_prot = prot; if (address >= end) { if (!after_bootmem) { @@ -343,45 +348,58 @@ phys_pmd_init(pmd_t *pmd_page, unsigned long address, unsigned long end, if (!pmd_large(*pmd)) { spin_lock(&init_mm.page_table_lock); last_map_addr = phys_pte_update(pmd, address, - end); + end, prot); spin_unlock(&init_mm.page_table_lock); continue; } - goto repeat_set_pte; + /* + * If we are ok with PG_LEVEL_2M mapping, then we will + * use the existing mapping, + * + * Otherwise, we will split the large page mapping but + * use the same existing protection bits except for + * large page, so that we don't violate Intel's TLB + * Application note (317080) which says, while changing + * the page sizes, new and old translations should + * not differ with respect to page frame and + * attributes. + */ + if (page_size_mask & (1 << PG_LEVEL_2M)) + continue; + new_prot = pte_pgprot(pte_clrhuge(*(pte_t *)pmd)); } if (page_size_mask & (1<<PG_LEVEL_2M)) { pages++; -repeat_set_pte: spin_lock(&init_mm.page_table_lock); set_pte((pte_t *)pmd, - pfn_pte(address >> PAGE_SHIFT, PAGE_KERNEL_LARGE)); + pfn_pte(address >> PAGE_SHIFT, + __pgprot(pgprot_val(prot) | _PAGE_PSE))); spin_unlock(&init_mm.page_table_lock); last_map_addr = (address & PMD_MASK) + PMD_SIZE; continue; } pte = alloc_low_page(&pte_phys); - last_map_addr = phys_pte_init(pte, address, end); + last_map_addr = phys_pte_init(pte, address, end, new_prot); unmap_low_page(pte); spin_lock(&init_mm.page_table_lock); pmd_populate_kernel(&init_mm, pmd, __va(pte_phys)); spin_unlock(&init_mm.page_table_lock); } - if (physical_mapping_iter == 1) - update_page_count(PG_LEVEL_2M, pages); + update_page_count(PG_LEVEL_2M, pages); return last_map_addr; } static unsigned long __meminit phys_pmd_update(pud_t *pud, unsigned long address, unsigned long end, - unsigned long page_size_mask) + unsigned long page_size_mask, pgprot_t prot) { pmd_t *pmd = pmd_offset(pud, 0); unsigned long last_map_addr; - last_map_addr = phys_pmd_init(pmd, address, end, page_size_mask); + last_map_addr = phys_pmd_init(pmd, address, end, page_size_mask, prot); __flush_tlb_all(); return last_map_addr; } @@ -398,6 +416,7 @@ phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end, unsigned long pmd_phys; pud_t *pud = pud_page + pud_index(addr); pmd_t *pmd; + pgprot_t prot = PAGE_KERNEL; if (addr >= end) break; @@ -411,16 +430,28 @@ phys_pud_init(pud_t *pud_page, unsigned long addr, unsigned long end, if (pud_val(*pud)) { if (!pud_large(*pud)) { last_map_addr = phys_pmd_update(pud, addr, end, - page_size_mask); + page_size_mask, prot); continue; } - - goto repeat_set_pte; + /* + * If we are ok with PG_LEVEL_1G mapping, then we will + * use the existing mapping. + * + * Otherwise, we will split the gbpage mapping but use + * the same existing protection bits except for large + * page, so that we don't violate Intel's TLB + * Application note (317080) which says, while changing + * the page sizes, new and old translations should + * not differ with respect to page frame and + * attributes. + */ + if (page_size_mask & (1 << PG_LEVEL_1G)) + continue; + prot = pte_pgprot(pte_clrhuge(*(pte_t *)pud)); } if (page_size_mask & (1<<PG_LEVEL_1G)) { pages++; -repeat_set_pte: spin_lock(&init_mm.page_table_lock); set_pte((pte_t *)pud, pfn_pte(addr >> PAGE_SHIFT, PAGE_KERNEL_LARGE)); @@ -430,7 +461,8 @@ repeat_set_pte: } pmd = alloc_low_page(&pmd_phys); - last_map_addr = phys_pmd_init(pmd, addr, end, page_size_mask); + last_map_addr = phys_pmd_init(pmd, addr, end, page_size_mask, + prot); unmap_low_page(pmd); spin_lock(&init_mm.page_table_lock); @@ -439,8 +471,7 @@ repeat_set_pte: } __flush_tlb_all(); - if (physical_mapping_iter == 1) - update_page_count(PG_LEVEL_1G, pages); + update_page_count(PG_LEVEL_1G, pages); return last_map_addr; } @@ -505,54 +536,15 @@ static void __init init_gbpages(void) direct_gbpages = 0; } -static int is_kernel(unsigned long pfn) -{ - unsigned long pg_addresss = pfn << PAGE_SHIFT; - - if (pg_addresss >= (unsigned long) __pa(_text) && - pg_addresss < (unsigned long) __pa(_end)) - return 1; - - return 0; -} - static unsigned long __init kernel_physical_mapping_init(unsigned long start, unsigned long end, unsigned long page_size_mask) { - unsigned long next, last_map_addr; - u64 cached_supported_pte_mask = __supported_pte_mask; - unsigned long cache_start = start; - unsigned long cache_end = end; - - /* - * First iteration will setup identity mapping using large/small pages - * based on page_size_mask, with other attributes same as set by - * the early code in head_64.S - * - * Second iteration will setup the appropriate attributes - * 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." - * - * For now, only difference between very early PTE attributes used in - * head_64.S and here is _PAGE_NX. - */ - BUILD_BUG_ON((__PAGE_KERNEL_LARGE & ~__PAGE_KERNEL_IDENT_LARGE_EXEC) - != _PAGE_NX); - __supported_pte_mask &= ~(_PAGE_NX); - physical_mapping_iter = 1; + unsigned long next, last_map_addr = end; -repeat: - last_map_addr = cache_end; - - start = (unsigned long)__va(cache_start); - end = (unsigned long)__va(cache_end); + start = (unsigned long)__va(start); + end = (unsigned long)__va(end); for (; start < end; start = next) { pgd_t *pgd = pgd_offset_k(start); @@ -564,21 +556,11 @@ repeat: next = end; if (pgd_val(*pgd)) { - /* - * Static identity mappings will be overwritten - * with run-time mappings. For example, this allows - * the static 0-1GB identity mapping to be mapped - * non-executable with this. - */ - if (is_kernel(pte_pfn(*((pte_t *) pgd)))) - goto realloc; - last_map_addr = phys_pud_update(pgd, __pa(start), __pa(end), page_size_mask); continue; } -realloc: pud = alloc_low_page(&pud_phys); last_map_addr = phys_pud_init(pud, __pa(start), __pa(next), page_size_mask); @@ -590,15 +572,6 @@ realloc: } __flush_tlb_all(); - if (physical_mapping_iter == 1) { - physical_mapping_iter = 2; - /* - * Second iteration will set the actual desired PTE attributes. - */ - __supported_pte_mask = cached_supported_pte_mask; - goto repeat; - } - return last_map_addr; } |
