diff options
Diffstat (limited to 'arch/s390/mm/pgtable.c')
| -rw-r--r-- | arch/s390/mm/pgtable.c | 871 |
1 files changed, 871 insertions, 0 deletions
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c new file mode 100644 index 00000000..6e765bf0 --- /dev/null +++ b/arch/s390/mm/pgtable.c @@ -0,0 +1,871 @@ +/* + * Copyright IBM Corp. 2007,2011 + * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com> + */ + +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/gfp.h> +#include <linux/mm.h> +#include <linux/swap.h> +#include <linux/smp.h> +#include <linux/highmem.h> +#include <linux/pagemap.h> +#include <linux/spinlock.h> +#include <linux/module.h> +#include <linux/quicklist.h> +#include <linux/rcupdate.h> +#include <linux/slab.h> + +#include <asm/pgtable.h> +#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 FRAG_MASK 0x0f +#else +#define ALLOC_ORDER 2 +#define FRAG_MASK 0x03 +#endif + + +unsigned long *crst_table_alloc(struct mm_struct *mm) +{ + struct page *page = alloc_pages(GFP_KERNEL, ALLOC_ORDER); + + if (!page) + return NULL; + return (unsigned long *) page_to_phys(page); +} + +void crst_table_free(struct mm_struct *mm, unsigned long *table) +{ + 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); + if (!table) + return -ENOMEM; + spin_lock_bh(&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; + mm->task_size = mm->context.asce_limit; + table = NULL; + } + spin_unlock_bh(&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); + mm->task_size = mm->context.asce_limit; + crst_table_free(mm, (unsigned long *) pgd); + } + update_mm(mm, current); +} +#endif + +#ifdef CONFIG_PGSTE + +/** + * gmap_alloc - allocate a guest address space + * @mm: pointer to the parent mm_struct + * + * Returns a guest address space structure. + */ +struct gmap *gmap_alloc(struct mm_struct *mm) +{ + struct gmap *gmap; + struct page *page; + unsigned long *table; + + gmap = kzalloc(sizeof(struct gmap), GFP_KERNEL); + if (!gmap) + goto out; + INIT_LIST_HEAD(&gmap->crst_list); + gmap->mm = mm; + page = alloc_pages(GFP_KERNEL, ALLOC_ORDER); + if (!page) + goto out_free; + list_add(&page->lru, &gmap->crst_list); + table = (unsigned long *) page_to_phys(page); + crst_table_init(table, _REGION1_ENTRY_EMPTY); + gmap->table = table; + gmap->asce = _ASCE_TYPE_REGION1 | _ASCE_TABLE_LENGTH | + _ASCE_USER_BITS | __pa(table); + list_add(&gmap->list, &mm->context.gmap_list); + return gmap; + +out_free: + kfree(gmap); +out: + return NULL; +} +EXPORT_SYMBOL_GPL(gmap_alloc); + +static int gmap_unlink_segment(struct gmap *gmap, unsigned long *table) +{ + struct gmap_pgtable *mp; + struct gmap_rmap *rmap; + struct page *page; + + if (*table & _SEGMENT_ENTRY_INV) + return 0; + page = pfn_to_page(*table >> PAGE_SHIFT); + mp = (struct gmap_pgtable *) page->index; + list_for_each_entry(rmap, &mp->mapper, list) { + if (rmap->entry != table) + continue; + list_del(&rmap->list); + kfree(rmap); + break; + } + *table = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | mp->vmaddr; + return 1; +} + +static void gmap_flush_tlb(struct gmap *gmap) +{ + if (MACHINE_HAS_IDTE) + __tlb_flush_idte((unsigned long) gmap->table | + _ASCE_TYPE_REGION1); + else + __tlb_flush_global(); +} + +/** + * gmap_free - free a guest address space + * @gmap: pointer to the guest address space structure + */ +void gmap_free(struct gmap *gmap) +{ + struct page *page, *next; + unsigned long *table; + int i; + + + /* Flush tlb. */ + if (MACHINE_HAS_IDTE) + __tlb_flush_idte((unsigned long) gmap->table | + _ASCE_TYPE_REGION1); + else + __tlb_flush_global(); + + /* Free all segment & region tables. */ + down_read(&gmap->mm->mmap_sem); + spin_lock(&gmap->mm->page_table_lock); + list_for_each_entry_safe(page, next, &gmap->crst_list, lru) { + table = (unsigned long *) page_to_phys(page); + if ((*table & _REGION_ENTRY_TYPE_MASK) == 0) + /* Remove gmap rmap structures for segment table. */ + for (i = 0; i < PTRS_PER_PMD; i++, table++) + gmap_unlink_segment(gmap, table); + __free_pages(page, ALLOC_ORDER); + } + spin_unlock(&gmap->mm->page_table_lock); + up_read(&gmap->mm->mmap_sem); + list_del(&gmap->list); + kfree(gmap); +} +EXPORT_SYMBOL_GPL(gmap_free); + +/** + * gmap_enable - switch primary space to the guest address space + * @gmap: pointer to the guest address space structure + */ +void gmap_enable(struct gmap *gmap) +{ + S390_lowcore.gmap = (unsigned long) gmap; +} +EXPORT_SYMBOL_GPL(gmap_enable); + +/** + * gmap_disable - switch back to the standard primary address space + * @gmap: pointer to the guest address space structure + */ +void gmap_disable(struct gmap *gmap) +{ + S390_lowcore.gmap = 0UL; +} +EXPORT_SYMBOL_GPL(gmap_disable); + +/* + * gmap_alloc_table is assumed to be called with mmap_sem held + */ +static int gmap_alloc_table(struct gmap *gmap, + unsigned long *table, unsigned long init) +{ + struct page *page; + unsigned long *new; + + /* since we dont free the gmap table until gmap_free we can unlock */ + spin_unlock(&gmap->mm->page_table_lock); + page = alloc_pages(GFP_KERNEL, ALLOC_ORDER); + spin_lock(&gmap->mm->page_table_lock); + if (!page) + return -ENOMEM; + new = (unsigned long *) page_to_phys(page); + crst_table_init(new, init); + if (*table & _REGION_ENTRY_INV) { + list_add(&page->lru, &gmap->crst_list); + *table = (unsigned long) new | _REGION_ENTRY_LENGTH | + (*table & _REGION_ENTRY_TYPE_MASK); + } else + __free_pages(page, ALLOC_ORDER); + return 0; +} + +/** + * gmap_unmap_segment - unmap segment from the guest address space + * @gmap: pointer to the guest address space structure + * @addr: address in the guest address space + * @len: length of the memory area to unmap + * + * Returns 0 if the unmap succeded, -EINVAL if not. + */ +int gmap_unmap_segment(struct gmap *gmap, unsigned long to, unsigned long len) +{ + unsigned long *table; + unsigned long off; + int flush; + + if ((to | len) & (PMD_SIZE - 1)) + return -EINVAL; + if (len == 0 || to + len < to) + return -EINVAL; + + flush = 0; + down_read(&gmap->mm->mmap_sem); + spin_lock(&gmap->mm->page_table_lock); + for (off = 0; off < len; off += PMD_SIZE) { + /* Walk the guest addr space page table */ + table = gmap->table + (((to + off) >> 53) & 0x7ff); + if (*table & _REGION_ENTRY_INV) + goto out; + table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); + table = table + (((to + off) >> 42) & 0x7ff); + if (*table & _REGION_ENTRY_INV) + goto out; + table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); + table = table + (((to + off) >> 31) & 0x7ff); + if (*table & _REGION_ENTRY_INV) + goto out; + table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); + table = table + (((to + off) >> 20) & 0x7ff); + + /* Clear segment table entry in guest address space. */ + flush |= gmap_unlink_segment(gmap, table); + *table = _SEGMENT_ENTRY_INV; + } +out: + spin_unlock(&gmap->mm->page_table_lock); + up_read(&gmap->mm->mmap_sem); + if (flush) + gmap_flush_tlb(gmap); + return 0; +} +EXPORT_SYMBOL_GPL(gmap_unmap_segment); + +/** + * gmap_mmap_segment - map a segment to the guest address space + * @gmap: pointer to the guest address space structure + * @from: source address in the parent address space + * @to: target address in the guest address space + * + * Returns 0 if the mmap succeded, -EINVAL or -ENOMEM if not. + */ +int gmap_map_segment(struct gmap *gmap, unsigned long from, + unsigned long to, unsigned long len) +{ + unsigned long *table; + unsigned long off; + int flush; + + if ((from | to | len) & (PMD_SIZE - 1)) + return -EINVAL; + if (len == 0 || from + len > PGDIR_SIZE || + from + len < from || to + len < to) + return -EINVAL; + + flush = 0; + down_read(&gmap->mm->mmap_sem); + spin_lock(&gmap->mm->page_table_lock); + for (off = 0; off < len; off += PMD_SIZE) { + /* Walk the gmap address space page table */ + table = gmap->table + (((to + off) >> 53) & 0x7ff); + if ((*table & _REGION_ENTRY_INV) && + gmap_alloc_table(gmap, table, _REGION2_ENTRY_EMPTY)) + goto out_unmap; + table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); + table = table + (((to + off) >> 42) & 0x7ff); + if ((*table & _REGION_ENTRY_INV) && + gmap_alloc_table(gmap, table, _REGION3_ENTRY_EMPTY)) + goto out_unmap; + table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); + table = table + (((to + off) >> 31) & 0x7ff); + if ((*table & _REGION_ENTRY_INV) && + gmap_alloc_table(gmap, table, _SEGMENT_ENTRY_EMPTY)) + goto out_unmap; + table = (unsigned long *) (*table & _REGION_ENTRY_ORIGIN); + table = table + (((to + off) >> 20) & 0x7ff); + + /* Store 'from' address in an invalid segment table entry. */ + flush |= gmap_unlink_segment(gmap, table); + *table = _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | (from + off); + } + spin_unlock(&gmap->mm->page_table_lock); + up_read(&gmap->mm->mmap_sem); + if (flush) + gmap_flush_tlb(gmap); + return 0; + +out_unmap: + spin_unlock(&gmap->mm->page_table_lock); + up_read(&gmap->mm->mmap_sem); + gmap_unmap_segment(gmap, to, len); + return -ENOMEM; +} +EXPORT_SYMBOL_GPL(gmap_map_segment); + +/* + * this function is assumed to be called with mmap_sem held + */ +unsigned long __gmap_fault(unsigned long address, struct gmap *gmap) +{ + unsigned long *table, vmaddr, segment; + struct mm_struct *mm; + struct gmap_pgtable *mp; + struct gmap_rmap *rmap; + struct vm_area_struct *vma; + struct page *page; + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + + current->thread.gmap_addr = address; + mm = gmap->mm; + /* Walk the gmap address space page table */ + table = gmap->table + ((address >> 53) & 0x7ff); + if (unlikely(*table & _REGION_ENTRY_INV)) + return -EFAULT; + table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); + table = table + ((address >> 42) & 0x7ff); + if (unlikely(*table & _REGION_ENTRY_INV)) + return -EFAULT; + table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); + table = table + ((address >> 31) & 0x7ff); + if (unlikely(*table & _REGION_ENTRY_INV)) + return -EFAULT; + table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); + table = table + ((address >> 20) & 0x7ff); + + /* Convert the gmap address to an mm address. */ + segment = *table; + if (likely(!(segment & _SEGMENT_ENTRY_INV))) { + page = pfn_to_page(segment >> PAGE_SHIFT); + mp = (struct gmap_pgtable *) page->index; + return mp->vmaddr | (address & ~PMD_MASK); + } else if (segment & _SEGMENT_ENTRY_RO) { + vmaddr = segment & _SEGMENT_ENTRY_ORIGIN; + vma = find_vma(mm, vmaddr); + if (!vma || vma->vm_start > vmaddr) + return -EFAULT; + + /* Walk the parent mm page table */ + pgd = pgd_offset(mm, vmaddr); + pud = pud_alloc(mm, pgd, vmaddr); + if (!pud) + return -ENOMEM; + pmd = pmd_alloc(mm, pud, vmaddr); + if (!pmd) + return -ENOMEM; + if (!pmd_present(*pmd) && + __pte_alloc(mm, vma, pmd, vmaddr)) + return -ENOMEM; + /* pmd now points to a valid segment table entry. */ + rmap = kmalloc(sizeof(*rmap), GFP_KERNEL|__GFP_REPEAT); + if (!rmap) + return -ENOMEM; + /* Link gmap segment table entry location to page table. */ + page = pmd_page(*pmd); + mp = (struct gmap_pgtable *) page->index; + rmap->entry = table; + spin_lock(&mm->page_table_lock); + list_add(&rmap->list, &mp->mapper); + spin_unlock(&mm->page_table_lock); + /* Set gmap segment table entry to page table. */ + *table = pmd_val(*pmd) & PAGE_MASK; + return vmaddr | (address & ~PMD_MASK); + } + return -EFAULT; +} + +unsigned long gmap_fault(unsigned long address, struct gmap *gmap) +{ + unsigned long rc; + + down_read(&gmap->mm->mmap_sem); + rc = __gmap_fault(address, gmap); + up_read(&gmap->mm->mmap_sem); + + return rc; +} +EXPORT_SYMBOL_GPL(gmap_fault); + +void gmap_discard(unsigned long from, unsigned long to, struct gmap *gmap) +{ + + unsigned long *table, address, size; + struct vm_area_struct *vma; + struct gmap_pgtable *mp; + struct page *page; + + down_read(&gmap->mm->mmap_sem); + address = from; + while (address < to) { + /* Walk the gmap address space page table */ + table = gmap->table + ((address >> 53) & 0x7ff); + if (unlikely(*table & _REGION_ENTRY_INV)) { + address = (address + PMD_SIZE) & PMD_MASK; + continue; + } + table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); + table = table + ((address >> 42) & 0x7ff); + if (unlikely(*table & _REGION_ENTRY_INV)) { + address = (address + PMD_SIZE) & PMD_MASK; + continue; + } + table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); + table = table + ((address >> 31) & 0x7ff); + if (unlikely(*table & _REGION_ENTRY_INV)) { + address = (address + PMD_SIZE) & PMD_MASK; + continue; + } + table = (unsigned long *)(*table & _REGION_ENTRY_ORIGIN); + table = table + ((address >> 20) & 0x7ff); + if (unlikely(*table & _SEGMENT_ENTRY_INV)) { + address = (address + PMD_SIZE) & PMD_MASK; + continue; + } + page = pfn_to_page(*table >> PAGE_SHIFT); + mp = (struct gmap_pgtable *) page->index; + vma = find_vma(gmap->mm, mp->vmaddr); + size = min(to - address, PMD_SIZE - (address & ~PMD_MASK)); + zap_page_range(vma, mp->vmaddr | (address & ~PMD_MASK), + size, NULL); + address = (address + PMD_SIZE) & PMD_MASK; + } + up_read(&gmap->mm->mmap_sem); +} +EXPORT_SYMBOL_GPL(gmap_discard); + +void gmap_unmap_notifier(struct mm_struct *mm, unsigned long *table) +{ + struct gmap_rmap *rmap, *next; + struct gmap_pgtable *mp; + struct page *page; + int flush; + + flush = 0; + spin_lock(&mm->page_table_lock); + page = pfn_to_page(__pa(table) >> PAGE_SHIFT); + mp = (struct gmap_pgtable *) page->index; + list_for_each_entry_safe(rmap, next, &mp->mapper, list) { + *rmap->entry = + _SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO | mp->vmaddr; + list_del(&rmap->list); + kfree(rmap); + flush = 1; + } + spin_unlock(&mm->page_table_lock); + if (flush) + __tlb_flush_global(); +} + +static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm, + unsigned long vmaddr) +{ + struct page *page; + unsigned long *table; + struct gmap_pgtable *mp; + + page = alloc_page(GFP_KERNEL|__GFP_REPEAT); + if (!page) + return NULL; + mp = kmalloc(sizeof(*mp), GFP_KERNEL|__GFP_REPEAT); + if (!mp) { + __free_page(page); + return NULL; + } + pgtable_page_ctor(page); + mp->vmaddr = vmaddr & PMD_MASK; + INIT_LIST_HEAD(&mp->mapper); + page->index = (unsigned long) mp; + atomic_set(&page->_mapcount, 3); + table = (unsigned long *) page_to_phys(page); + clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE/2); + clear_table(table + PTRS_PER_PTE, 0, PAGE_SIZE/2); + return table; +} + +static inline void page_table_free_pgste(unsigned long *table) +{ + struct page *page; + struct gmap_pgtable *mp; + + page = pfn_to_page(__pa(table) >> PAGE_SHIFT); + mp = (struct gmap_pgtable *) page->index; + BUG_ON(!list_empty(&mp->mapper)); + pgtable_page_dtor(page); + atomic_set(&page->_mapcount, -1); + kfree(mp); + __free_page(page); +} + +#else /* CONFIG_PGSTE */ + +static inline unsigned long *page_table_alloc_pgste(struct mm_struct *mm, + unsigned long vmaddr) +{ + return NULL; +} + +static inline void page_table_free_pgste(unsigned long *table) +{ +} + +static inline void gmap_unmap_notifier(struct mm_struct *mm, + unsigned long *table) +{ +} + +#endif /* CONFIG_PGSTE */ + +static inline unsigned int atomic_xor_bits(atomic_t *v, unsigned int bits) +{ + unsigned int old, new; + + do { + old = atomic_read(v); + new = old ^ bits; + } while (atomic_cmpxchg(v, old, new) != old); + return new; +} + +/* + * page table entry allocation/free routines. + */ +unsigned long *page_table_alloc(struct mm_struct *mm, unsigned long vmaddr) +{ + struct page *page; + unsigned long *table; + unsigned int mask, bit; + + if (mm_has_pgste(mm)) + return page_table_alloc_pgste(mm, vmaddr); + /* Allocate fragments of a 4K page as 1K/2K page table */ + spin_lock_bh(&mm->context.list_lock); + mask = FRAG_MASK; + if (!list_empty(&mm->context.pgtable_list)) { + page = list_first_entry(&mm->context.pgtable_list, + struct page, lru); + table = (unsigned long *) page_to_phys(page); + mask = atomic_read(&page->_mapcount); + mask = mask | (mask >> 4); + } + if ((mask & FRAG_MASK) == FRAG_MASK) { + spin_unlock_bh(&mm->context.list_lock); + page = alloc_page(GFP_KERNEL|__GFP_REPEAT); + if (!page) + return NULL; + pgtable_page_ctor(page); + atomic_set(&page->_mapcount, 1); + table = (unsigned long *) page_to_phys(page); + clear_table(table, _PAGE_TYPE_EMPTY, PAGE_SIZE); + spin_lock_bh(&mm->context.list_lock); + list_add(&page->lru, &mm->context.pgtable_list); + } else { + for (bit = 1; mask & bit; bit <<= 1) + table += PTRS_PER_PTE; + mask = atomic_xor_bits(&page->_mapcount, bit); + if ((mask & FRAG_MASK) == FRAG_MASK) + list_del(&page->lru); + } + spin_unlock_bh(&mm->context.list_lock); + return table; +} + +void page_table_free(struct mm_struct *mm, unsigned long *table) +{ + struct page *page; + unsigned int bit, mask; + + if (mm_has_pgste(mm)) { + gmap_unmap_notifier(mm, table); + return page_table_free_pgste(table); + } + /* Free 1K/2K page table fragment of a 4K page */ + page = pfn_to_page(__pa(table) >> PAGE_SHIFT); + bit = 1 << ((__pa(table) & ~PAGE_MASK)/(PTRS_PER_PTE*sizeof(pte_t))); + spin_lock_bh(&mm->context.list_lock); + if ((atomic_read(&page->_mapcount) & FRAG_MASK) != FRAG_MASK) + list_del(&page->lru); + mask = atomic_xor_bits(&page->_mapcount, bit); + if (mask & FRAG_MASK) + list_add(&page->lru, &mm->context.pgtable_list); + spin_unlock_bh(&mm->context.list_lock); + if (mask == 0) { + pgtable_page_dtor(page); + atomic_set(&page->_mapcount, -1); + __free_page(page); + } +} + +static void __page_table_free_rcu(void *table, unsigned bit) +{ + struct page *page; + + if (bit == FRAG_MASK) + return page_table_free_pgste(table); + /* Free 1K/2K page table fragment of a 4K page */ + page = pfn_to_page(__pa(table) >> PAGE_SHIFT); + if (atomic_xor_bits(&page->_mapcount, bit) == 0) { + pgtable_page_dtor(page); + atomic_set(&page->_mapcount, -1); + __free_page(page); + } +} + +void page_table_free_rcu(struct mmu_gather *tlb, unsigned long *table) +{ + struct mm_struct *mm; + struct page *page; + unsigned int bit, mask; + + mm = tlb->mm; + if (mm_has_pgste(mm)) { + gmap_unmap_notifier(mm, table); + table = (unsigned long *) (__pa(table) | FRAG_MASK); + tlb_remove_table(tlb, table); + return; + } + bit = 1 << ((__pa(table) & ~PAGE_MASK) / (PTRS_PER_PTE*sizeof(pte_t))); + page = pfn_to_page(__pa(table) >> PAGE_SHIFT); + spin_lock_bh(&mm->context.list_lock); + if ((atomic_read(&page->_mapcount) & FRAG_MASK) != FRAG_MASK) + list_del(&page->lru); + mask = atomic_xor_bits(&page->_mapcount, bit | (bit << 4)); + if (mask & FRAG_MASK) + list_add_tail(&page->lru, &mm->context.pgtable_list); + spin_unlock_bh(&mm->context.list_lock); + table = (unsigned long *) (__pa(table) | (bit << 4)); + tlb_remove_table(tlb, table); +} + +void __tlb_remove_table(void *_table) +{ + const unsigned long mask = (FRAG_MASK << 4) | FRAG_MASK; + void *table = (void *)((unsigned long) _table & ~mask); + unsigned type = (unsigned long) _table & mask; + + if (type) + __page_table_free_rcu(table, type); + else + free_pages((unsigned long) table, ALLOC_ORDER); +} + +static void tlb_remove_table_smp_sync(void *arg) +{ + /* Simply deliver the interrupt */ +} + +static void tlb_remove_table_one(void *table) +{ + /* + * This isn't an RCU grace period and hence the page-tables cannot be + * assumed to be actually RCU-freed. + * + * It is however sufficient for software page-table walkers that rely + * on IRQ disabling. See the comment near struct mmu_table_batch. + */ + smp_call_function(tlb_remove_table_smp_sync, NULL, 1); + __tlb_remove_table(table); +} + +static void tlb_remove_table_rcu(struct rcu_head *head) +{ + struct mmu_table_batch *batch; + int i; + + batch = container_of(head, struct mmu_table_batch, rcu); + + for (i = 0; i < batch->nr; i++) + __tlb_remove_table(batch->tables[i]); + + free_page((unsigned long)batch); +} + +void tlb_table_flush(struct mmu_gather *tlb) +{ + struct mmu_table_batch **batch = &tlb->batch; + + if (*batch) { + __tlb_flush_mm(tlb->mm); + call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu); + *batch = NULL; + } +} + +void tlb_remove_table(struct mmu_gather *tlb, void *table) +{ + struct mmu_table_batch **batch = &tlb->batch; + + if (*batch == NULL) { + *batch = (struct mmu_table_batch *) + __get_free_page(GFP_NOWAIT | __GFP_NOWARN); + if (*batch == NULL) { + __tlb_flush_mm(tlb->mm); + tlb_remove_table_one(table); + return; + } + (*batch)->nr = 0; + } + (*batch)->tables[(*batch)->nr++] = table; + if ((*batch)->nr == MAX_TABLE_BATCH) + tlb_table_flush(tlb); +} + +/* + * switch on pgstes for its userspace process (for kvm) + */ +int s390_enable_sie(void) +{ + struct task_struct *tsk = current; + struct mm_struct *mm, *old_mm; + + /* Do we have switched amode? If no, we cannot do sie */ + if (user_mode == HOME_SPACE_MODE) + return -EINVAL; + + /* Do we have pgstes? if yes, we are done */ + if (mm_has_pgste(tsk->mm)) + return 0; + + /* lets check if we are allowed to replace the mm */ + task_lock(tsk); + if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 || +#ifdef CONFIG_AIO + !hlist_empty(&tsk->mm->ioctx_list) || +#endif + tsk->mm != tsk->active_mm) { + task_unlock(tsk); + return -EINVAL; + } + task_unlock(tsk); + + /* we copy the mm and let dup_mm create the page tables with_pgstes */ + tsk->mm->context.alloc_pgste = 1; + mm = dup_mm(tsk); + tsk->mm->context.alloc_pgste = 0; + if (!mm) + return -ENOMEM; + + /* Now lets check again if something happened */ + task_lock(tsk); + if (!tsk->mm || atomic_read(&tsk->mm->mm_users) > 1 || +#ifdef CONFIG_AIO + !hlist_empty(&tsk->mm->ioctx_list) || +#endif + tsk->mm != tsk->active_mm) { + mmput(mm); + task_unlock(tsk); + return -EINVAL; + } + + /* ok, we are alone. No ptrace, no threads, etc. */ + old_mm = tsk->mm; + tsk->mm = tsk->active_mm = mm; + preempt_disable(); + update_mm(mm, tsk); + atomic_inc(&mm->context.attach_count); + atomic_dec(&old_mm->context.attach_count); + cpumask_set_cpu(smp_processor_id(), mm_cpumask(mm)); + preempt_enable(); + task_unlock(tsk); + mmput(old_mm); + return 0; +} +EXPORT_SYMBOL_GPL(s390_enable_sie); + +#if defined(CONFIG_DEBUG_PAGEALLOC) && defined(CONFIG_HIBERNATION) +bool kernel_page_present(struct page *page) +{ + unsigned long addr; + int cc; + + addr = page_to_phys(page); + asm volatile( + " lra %1,0(%1)\n" + " ipm %0\n" + " srl %0,28" + : "=d" (cc), "+a" (addr) : : "cc"); + return cc == 0; +} +#endif /* CONFIG_HIBERNATION && CONFIG_DEBUG_PAGEALLOC */ |