diff options
Diffstat (limited to 'arch/s390/mm/pgtable.c')
-rw-r--r-- | arch/s390/mm/pgtable.c | 174 |
1 files changed, 155 insertions, 19 deletions
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index e60e0ae..fd07201 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -23,11 +23,18 @@ #include <asm/pgalloc.h> #include <asm/tlb.h> #include <asm/tlbflush.h> +#include <asm/mmu_context.h> #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) @@ -45,50 +52,179 @@ 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); } +#ifdef CONFIG_64BIT +int crst_table_upgrade(struct mm_struct *mm, unsigned long limit) +{ + unsigned long *table, *pgd; + unsigned long entry; + + BUG_ON(limit > (1UL << 53)); +repeat: + table = crst_table_alloc(mm, mm->context.noexec); + if (!table) + return -ENOMEM; + spin_lock(&mm->page_table_lock); + if (mm->context.asce_limit < limit) { + pgd = (unsigned long *) mm->pgd; + if (mm->context.asce_limit <= (1UL << 31)) { + entry = _REGION3_ENTRY_EMPTY; + mm->context.asce_limit = 1UL << 42; + mm->context.asce_bits = _ASCE_TABLE_LENGTH | + _ASCE_USER_BITS | + _ASCE_TYPE_REGION3; + } else { + entry = _REGION2_ENTRY_EMPTY; + mm->context.asce_limit = 1UL << 53; + mm->context.asce_bits = _ASCE_TABLE_LENGTH | + _ASCE_USER_BITS | + _ASCE_TYPE_REGION2; + } + crst_table_init(table, entry); + pgd_populate(mm, (pgd_t *) table, (pud_t *) pgd); + mm->pgd = (pgd_t *) table; + table = NULL; + } + spin_unlock(&mm->page_table_lock); + if (table) + crst_table_free(mm, table); + if (mm->context.asce_limit < limit) + goto repeat; + update_mm(mm, current); + return 0; +} + +void crst_table_downgrade(struct mm_struct *mm, unsigned long limit) +{ + pgd_t *pgd; + + if (mm->context.asce_limit <= limit) + return; + __tlb_flush_mm(mm); + while (mm->context.asce_limit > limit) { + pgd = mm->pgd; + switch (pgd_val(*pgd) & _REGION_ENTRY_TYPE_MASK) { + case _REGION_ENTRY_TYPE_R2: + mm->context.asce_limit = 1UL << 42; + mm->context.asce_bits = _ASCE_TABLE_LENGTH | + _ASCE_USER_BITS | + _ASCE_TYPE_REGION3; + break; + case _REGION_ENTRY_TYPE_R3: + mm->context.asce_limit = 1UL << 31; + mm->context.asce_bits = _ASCE_TABLE_LENGTH | + _ASCE_USER_BITS | + _ASCE_TYPE_SEGMENT; + break; + default: + BUG(); + } + mm->pgd = (pgd_t *) (pgd_val(*pgd) & _REGION_ENTRY_ORIGIN); + crst_table_free(mm, (unsigned long *) pgd); + } + update_mm(mm, current); +} +#endif + /* * 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); } 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; - 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); } |