From 146e4b3c8b92071b18f0b2e6f47165bad4f9e825 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Sat, 9 Feb 2008 18:24:35 +0100 Subject: [S390] 1K/2K page table pages. This patch implements 1K/2K page table pages for s390. Signed-off-by: Martin Schwidefsky --- arch/s390/mm/init.c | 2 +- arch/s390/mm/pgtable.c | 102 +++++++++++++++++++++++++++++++++++++++---------- arch/s390/mm/vmem.c | 14 +++++-- 3 files changed, 93 insertions(+), 25 deletions(-) (limited to 'arch/s390/mm') diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index 983ec6ec0e7c..01dfe20f846d 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -184,7 +184,7 @@ void kernel_map_pages(struct page *page, int numpages, int enable) pmd = pmd_offset(pud, address); pte = pte_offset_kernel(pmd, address); if (!enable) { - ptep_invalidate(address, pte); + ptep_invalidate(&init_mm, address, pte); continue; } *pte = mk_pte_phys(address, __pgprot(_PAGE_TYPE_RW)); diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index 019f518cd5a0..809e77893039 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -26,8 +26,14 @@ #ifndef CONFIG_64BIT #define ALLOC_ORDER 1 +#define TABLES_PER_PAGE 4 +#define FRAG_MASK 15UL +#define SECOND_HALVES 10UL #else #define ALLOC_ORDER 2 +#define TABLES_PER_PAGE 2 +#define FRAG_MASK 3UL +#define SECOND_HALVES 2UL #endif unsigned long *crst_table_alloc(struct mm_struct *mm, int noexec) @@ -45,13 +51,20 @@ unsigned long *crst_table_alloc(struct mm_struct *mm, int noexec) } page->index = page_to_phys(shadow); } + spin_lock(&mm->page_table_lock); + list_add(&page->lru, &mm->context.crst_list); + spin_unlock(&mm->page_table_lock); return (unsigned long *) page_to_phys(page); } -void crst_table_free(unsigned long *table) +void crst_table_free(struct mm_struct *mm, unsigned long *table) { unsigned long *shadow = get_shadow_table(table); + struct page *page = virt_to_page(table); + spin_lock(&mm->page_table_lock); + list_del(&page->lru); + spin_unlock(&mm->page_table_lock); if (shadow) free_pages((unsigned long) shadow, ALLOC_ORDER); free_pages((unsigned long) table, ALLOC_ORDER); @@ -60,37 +73,84 @@ void crst_table_free(unsigned long *table) /* * page table entry allocation/free routines. */ -unsigned long *page_table_alloc(int noexec) +unsigned long *page_table_alloc(struct mm_struct *mm) { - struct page *page = alloc_page(GFP_KERNEL); + struct page *page; unsigned long *table; + unsigned long bits; - if (!page) - return NULL; - page->index = 0; - if (noexec) { - struct page *shadow = alloc_page(GFP_KERNEL); - if (!shadow) { - __free_page(page); + bits = mm->context.noexec ? 3UL : 1UL; + spin_lock(&mm->page_table_lock); + page = NULL; + if (!list_empty(&mm->context.pgtable_list)) { + page = list_first_entry(&mm->context.pgtable_list, + struct page, lru); + if ((page->flags & FRAG_MASK) == ((1UL << TABLES_PER_PAGE) - 1)) + page = NULL; + } + if (!page) { + spin_unlock(&mm->page_table_lock); + page = alloc_page(GFP_KERNEL|__GFP_REPEAT); + if (!page) return NULL; - } - table = (unsigned long *) page_to_phys(shadow); + pgtable_page_ctor(page); + page->flags &= ~FRAG_MASK; + table = (unsigned long *) page_to_phys(page); clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE); - page->index = (addr_t) table; + spin_lock(&mm->page_table_lock); + list_add(&page->lru, &mm->context.pgtable_list); } - pgtable_page_ctor(page); table = (unsigned long *) page_to_phys(page); - clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE); + while (page->flags & bits) { + table += 256; + bits <<= 1; + } + page->flags |= bits; + if ((page->flags & FRAG_MASK) == ((1UL << TABLES_PER_PAGE) - 1)) + list_move_tail(&page->lru, &mm->context.pgtable_list); + spin_unlock(&mm->page_table_lock); return table; } -void page_table_free(unsigned long *table) +void page_table_free(struct mm_struct *mm, unsigned long *table) { - unsigned long *shadow = get_shadow_pte(table); + struct page *page; + unsigned long bits; - pgtable_page_dtor(virt_to_page(table)); - if (shadow) - free_page((unsigned long) shadow); - free_page((unsigned long) table); + bits = mm->context.noexec ? 3UL : 1UL; + bits <<= (__pa(table) & (PAGE_SIZE - 1)) / 256 / sizeof(unsigned long); + page = pfn_to_page(__pa(table) >> PAGE_SHIFT); + spin_lock(&mm->page_table_lock); + page->flags ^= bits; + if (page->flags & FRAG_MASK) { + /* Page now has some free pgtable fragments. */ + list_move(&page->lru, &mm->context.pgtable_list); + page = NULL; + } else + /* All fragments of the 4K page have been freed. */ + list_del(&page->lru); + spin_unlock(&mm->page_table_lock); + if (page) { + pgtable_page_dtor(page); + __free_page(page); + } +} +void disable_noexec(struct mm_struct *mm, struct task_struct *tsk) +{ + struct page *page; + + spin_lock(&mm->page_table_lock); + /* Free shadow region and segment tables. */ + list_for_each_entry(page, &mm->context.crst_list, lru) + if (page->index) { + free_pages((unsigned long) page->index, ALLOC_ORDER); + page->index = 0; + } + /* "Free" second halves of page tables. */ + list_for_each_entry(page, &mm->context.pgtable_list, lru) + page->flags &= ~SECOND_HALVES; + spin_unlock(&mm->page_table_lock); + mm->context.noexec = 0; + update_mm(mm, tsk); } diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c index 7c1287ccf788..434491f8f47c 100644 --- a/arch/s390/mm/vmem.c +++ b/arch/s390/mm/vmem.c @@ -84,13 +84,18 @@ static inline pmd_t *vmem_pmd_alloc(void) return pmd; } -static inline pte_t *vmem_pte_alloc(void) +static pte_t __init_refok *vmem_pte_alloc(void) { - pte_t *pte = vmem_alloc_pages(0); + pte_t *pte; + if (slab_is_available()) + pte = (pte_t *) page_table_alloc(&init_mm); + else + pte = alloc_bootmem(PTRS_PER_PTE * sizeof(pte_t)); if (!pte) return NULL; - clear_table((unsigned long *) pte, _PAGE_TYPE_EMPTY, PAGE_SIZE); + clear_table((unsigned long *) pte, _PAGE_TYPE_EMPTY, + PTRS_PER_PTE * sizeof(pte_t)); return pte; } @@ -360,6 +365,9 @@ void __init vmem_map_init(void) { int i; + INIT_LIST_HEAD(&init_mm.context.crst_list); + INIT_LIST_HEAD(&init_mm.context.pgtable_list); + init_mm.context.noexec = 0; NODE_DATA(0)->node_mem_map = VMEM_MAP; for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) vmem_add_mem(memory_chunk[i].addr, memory_chunk[i].size); -- cgit v1.2.3