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Diffstat (limited to '')
| -rw-r--r-- | arch/powerpc/mm/mmu_context_iommu.c | 467 |
1 files changed, 467 insertions, 0 deletions
diff --git a/arch/powerpc/mm/mmu_context_iommu.c b/arch/powerpc/mm/mmu_context_iommu.c new file mode 100644 index 000000000..56c2234cc --- /dev/null +++ b/arch/powerpc/mm/mmu_context_iommu.c @@ -0,0 +1,467 @@ +/* + * IOMMU helpers in MMU context. + * + * Copyright (C) 2015 IBM Corp. <aik@ozlabs.ru> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version + * 2 of the License, or (at your option) any later version. + * + */ + +#include <linux/sched/signal.h> +#include <linux/slab.h> +#include <linux/rculist.h> +#include <linux/vmalloc.h> +#include <linux/mutex.h> +#include <linux/migrate.h> +#include <linux/hugetlb.h> +#include <linux/swap.h> +#include <linux/sizes.h> +#include <asm/mmu_context.h> +#include <asm/pte-walk.h> + +static DEFINE_MUTEX(mem_list_mutex); + +#define MM_IOMMU_TABLE_GROUP_PAGE_DIRTY 0x1 +#define MM_IOMMU_TABLE_GROUP_PAGE_MASK ~(SZ_4K - 1) + +struct mm_iommu_table_group_mem_t { + struct list_head next; + struct rcu_head rcu; + unsigned long used; + atomic64_t mapped; + unsigned int pageshift; + u64 ua; /* userspace address */ + u64 entries; /* number of entries in hpas[] */ + u64 *hpas; /* vmalloc'ed */ +}; + +static long mm_iommu_adjust_locked_vm(struct mm_struct *mm, + unsigned long npages, bool incr) +{ + long ret = 0, locked, lock_limit; + + if (!npages) + return 0; + + down_write(&mm->mmap_sem); + + if (incr) { + locked = mm->locked_vm + npages; + lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; + if (locked > lock_limit && !capable(CAP_IPC_LOCK)) + ret = -ENOMEM; + else + mm->locked_vm += npages; + } else { + if (WARN_ON_ONCE(npages > mm->locked_vm)) + npages = mm->locked_vm; + mm->locked_vm -= npages; + } + + pr_debug("[%d] RLIMIT_MEMLOCK HASH64 %c%ld %ld/%ld\n", + current ? current->pid : 0, + incr ? '+' : '-', + npages << PAGE_SHIFT, + mm->locked_vm << PAGE_SHIFT, + rlimit(RLIMIT_MEMLOCK)); + up_write(&mm->mmap_sem); + + return ret; +} + +bool mm_iommu_preregistered(struct mm_struct *mm) +{ + return !list_empty(&mm->context.iommu_group_mem_list); +} +EXPORT_SYMBOL_GPL(mm_iommu_preregistered); + +/* + * Taken from alloc_migrate_target with changes to remove CMA allocations + */ +struct page *new_iommu_non_cma_page(struct page *page, unsigned long private) +{ + gfp_t gfp_mask = GFP_USER; + struct page *new_page; + + if (PageCompound(page)) + return NULL; + + if (PageHighMem(page)) + gfp_mask |= __GFP_HIGHMEM; + + /* + * We don't want the allocation to force an OOM if possibe + */ + new_page = alloc_page(gfp_mask | __GFP_NORETRY | __GFP_NOWARN); + return new_page; +} + +static int mm_iommu_move_page_from_cma(struct page *page) +{ + int ret = 0; + LIST_HEAD(cma_migrate_pages); + + /* Ignore huge pages for now */ + if (PageCompound(page)) + return -EBUSY; + + lru_add_drain(); + ret = isolate_lru_page(page); + if (ret) + return ret; + + list_add(&page->lru, &cma_migrate_pages); + put_page(page); /* Drop the gup reference */ + + ret = migrate_pages(&cma_migrate_pages, new_iommu_non_cma_page, + NULL, 0, MIGRATE_SYNC, MR_CONTIG_RANGE); + if (ret) { + if (!list_empty(&cma_migrate_pages)) + putback_movable_pages(&cma_migrate_pages); + } + + return 0; +} + +long mm_iommu_get(struct mm_struct *mm, unsigned long ua, unsigned long entries, + struct mm_iommu_table_group_mem_t **pmem) +{ + struct mm_iommu_table_group_mem_t *mem; + long i, j, ret = 0, locked_entries = 0; + unsigned int pageshift; + unsigned long flags; + unsigned long cur_ua; + struct page *page = NULL; + + mutex_lock(&mem_list_mutex); + + list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, + next) { + if ((mem->ua == ua) && (mem->entries == entries)) { + ++mem->used; + *pmem = mem; + goto unlock_exit; + } + + /* Overlap? */ + if ((mem->ua < (ua + (entries << PAGE_SHIFT))) && + (ua < (mem->ua + + (mem->entries << PAGE_SHIFT)))) { + ret = -EINVAL; + goto unlock_exit; + } + + } + + ret = mm_iommu_adjust_locked_vm(mm, entries, true); + if (ret) + goto unlock_exit; + + locked_entries = entries; + + mem = kzalloc(sizeof(*mem), GFP_KERNEL); + if (!mem) { + ret = -ENOMEM; + goto unlock_exit; + } + + /* + * For a starting point for a maximum page size calculation + * we use @ua and @entries natural alignment to allow IOMMU pages + * smaller than huge pages but still bigger than PAGE_SIZE. + */ + mem->pageshift = __ffs(ua | (entries << PAGE_SHIFT)); + mem->hpas = vzalloc(array_size(entries, sizeof(mem->hpas[0]))); + if (!mem->hpas) { + kfree(mem); + ret = -ENOMEM; + goto unlock_exit; + } + + for (i = 0; i < entries; ++i) { + cur_ua = ua + (i << PAGE_SHIFT); + if (1 != get_user_pages_fast(cur_ua, + 1/* pages */, 1/* iswrite */, &page)) { + ret = -EFAULT; + for (j = 0; j < i; ++j) + put_page(pfn_to_page(mem->hpas[j] >> + PAGE_SHIFT)); + vfree(mem->hpas); + kfree(mem); + goto unlock_exit; + } + /* + * If we get a page from the CMA zone, since we are going to + * be pinning these entries, we might as well move them out + * of the CMA zone if possible. NOTE: faulting in + migration + * can be expensive. Batching can be considered later + */ + if (is_migrate_cma_page(page)) { + if (mm_iommu_move_page_from_cma(page)) + goto populate; + if (1 != get_user_pages_fast(cur_ua, + 1/* pages */, 1/* iswrite */, + &page)) { + ret = -EFAULT; + for (j = 0; j < i; ++j) + put_page(pfn_to_page(mem->hpas[j] >> + PAGE_SHIFT)); + vfree(mem->hpas); + kfree(mem); + goto unlock_exit; + } + } +populate: + pageshift = PAGE_SHIFT; + if (mem->pageshift > PAGE_SHIFT && PageCompound(page)) { + pte_t *pte; + struct page *head = compound_head(page); + unsigned int compshift = compound_order(head); + unsigned int pteshift; + + local_irq_save(flags); /* disables as well */ + pte = find_linux_pte(mm->pgd, cur_ua, NULL, &pteshift); + + /* Double check it is still the same pinned page */ + if (pte && pte_page(*pte) == head && + pteshift == compshift + PAGE_SHIFT) + pageshift = max_t(unsigned int, pteshift, + PAGE_SHIFT); + local_irq_restore(flags); + } + mem->pageshift = min(mem->pageshift, pageshift); + mem->hpas[i] = page_to_pfn(page) << PAGE_SHIFT; + } + + atomic64_set(&mem->mapped, 1); + mem->used = 1; + mem->ua = ua; + mem->entries = entries; + *pmem = mem; + + list_add_rcu(&mem->next, &mm->context.iommu_group_mem_list); + +unlock_exit: + if (locked_entries && ret) + mm_iommu_adjust_locked_vm(mm, locked_entries, false); + + mutex_unlock(&mem_list_mutex); + + return ret; +} +EXPORT_SYMBOL_GPL(mm_iommu_get); + +static void mm_iommu_unpin(struct mm_iommu_table_group_mem_t *mem) +{ + long i; + struct page *page = NULL; + + for (i = 0; i < mem->entries; ++i) { + if (!mem->hpas[i]) + continue; + + page = pfn_to_page(mem->hpas[i] >> PAGE_SHIFT); + if (!page) + continue; + + if (mem->hpas[i] & MM_IOMMU_TABLE_GROUP_PAGE_DIRTY) + SetPageDirty(page); + + put_page(page); + mem->hpas[i] = 0; + } +} + +static void mm_iommu_do_free(struct mm_iommu_table_group_mem_t *mem) +{ + + mm_iommu_unpin(mem); + vfree(mem->hpas); + kfree(mem); +} + +static void mm_iommu_free(struct rcu_head *head) +{ + struct mm_iommu_table_group_mem_t *mem = container_of(head, + struct mm_iommu_table_group_mem_t, rcu); + + mm_iommu_do_free(mem); +} + +static void mm_iommu_release(struct mm_iommu_table_group_mem_t *mem) +{ + list_del_rcu(&mem->next); + call_rcu(&mem->rcu, mm_iommu_free); +} + +long mm_iommu_put(struct mm_struct *mm, struct mm_iommu_table_group_mem_t *mem) +{ + long ret = 0; + + mutex_lock(&mem_list_mutex); + + if (mem->used == 0) { + ret = -ENOENT; + goto unlock_exit; + } + + --mem->used; + /* There are still users, exit */ + if (mem->used) + goto unlock_exit; + + /* Are there still mappings? */ + if (atomic_cmpxchg(&mem->mapped, 1, 0) != 1) { + ++mem->used; + ret = -EBUSY; + goto unlock_exit; + } + + /* @mapped became 0 so now mappings are disabled, release the region */ + mm_iommu_release(mem); + + mm_iommu_adjust_locked_vm(mm, mem->entries, false); + +unlock_exit: + mutex_unlock(&mem_list_mutex); + + return ret; +} +EXPORT_SYMBOL_GPL(mm_iommu_put); + +struct mm_iommu_table_group_mem_t *mm_iommu_lookup(struct mm_struct *mm, + unsigned long ua, unsigned long size) +{ + struct mm_iommu_table_group_mem_t *mem, *ret = NULL; + + list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next) { + if ((mem->ua <= ua) && + (ua + size <= mem->ua + + (mem->entries << PAGE_SHIFT))) { + ret = mem; + break; + } + } + + return ret; +} +EXPORT_SYMBOL_GPL(mm_iommu_lookup); + +struct mm_iommu_table_group_mem_t *mm_iommu_lookup_rm(struct mm_struct *mm, + unsigned long ua, unsigned long size) +{ + struct mm_iommu_table_group_mem_t *mem, *ret = NULL; + + list_for_each_entry_lockless(mem, &mm->context.iommu_group_mem_list, + next) { + if ((mem->ua <= ua) && + (ua + size <= mem->ua + + (mem->entries << PAGE_SHIFT))) { + ret = mem; + break; + } + } + + return ret; +} + +struct mm_iommu_table_group_mem_t *mm_iommu_find(struct mm_struct *mm, + unsigned long ua, unsigned long entries) +{ + struct mm_iommu_table_group_mem_t *mem, *ret = NULL; + + list_for_each_entry_rcu(mem, &mm->context.iommu_group_mem_list, next) { + if ((mem->ua == ua) && (mem->entries == entries)) { + ret = mem; + break; + } + } + + return ret; +} +EXPORT_SYMBOL_GPL(mm_iommu_find); + +long mm_iommu_ua_to_hpa(struct mm_iommu_table_group_mem_t *mem, + unsigned long ua, unsigned int pageshift, unsigned long *hpa) +{ + const long entry = (ua - mem->ua) >> PAGE_SHIFT; + u64 *va = &mem->hpas[entry]; + + if (entry >= mem->entries) + return -EFAULT; + + if (pageshift > mem->pageshift) + return -EFAULT; + + *hpa = (*va & MM_IOMMU_TABLE_GROUP_PAGE_MASK) | (ua & ~PAGE_MASK); + + return 0; +} +EXPORT_SYMBOL_GPL(mm_iommu_ua_to_hpa); + +long mm_iommu_ua_to_hpa_rm(struct mm_iommu_table_group_mem_t *mem, + unsigned long ua, unsigned int pageshift, unsigned long *hpa) +{ + const long entry = (ua - mem->ua) >> PAGE_SHIFT; + void *va = &mem->hpas[entry]; + unsigned long *pa; + + if (entry >= mem->entries) + return -EFAULT; + + if (pageshift > mem->pageshift) + return -EFAULT; + + pa = (void *) vmalloc_to_phys(va); + if (!pa) + return -EFAULT; + + *hpa = (*pa & MM_IOMMU_TABLE_GROUP_PAGE_MASK) | (ua & ~PAGE_MASK); + + return 0; +} + +extern void mm_iommu_ua_mark_dirty_rm(struct mm_struct *mm, unsigned long ua) +{ + struct mm_iommu_table_group_mem_t *mem; + long entry; + void *va; + unsigned long *pa; + + mem = mm_iommu_lookup_rm(mm, ua, PAGE_SIZE); + if (!mem) + return; + + entry = (ua - mem->ua) >> PAGE_SHIFT; + va = &mem->hpas[entry]; + + pa = (void *) vmalloc_to_phys(va); + if (!pa) + return; + + *pa |= MM_IOMMU_TABLE_GROUP_PAGE_DIRTY; +} + +long mm_iommu_mapped_inc(struct mm_iommu_table_group_mem_t *mem) +{ + if (atomic64_inc_not_zero(&mem->mapped)) + return 0; + + /* Last mm_iommu_put() has been called, no more mappings allowed() */ + return -ENXIO; +} +EXPORT_SYMBOL_GPL(mm_iommu_mapped_inc); + +void mm_iommu_mapped_dec(struct mm_iommu_table_group_mem_t *mem) +{ + atomic64_add_unless(&mem->mapped, -1, 1); +} +EXPORT_SYMBOL_GPL(mm_iommu_mapped_dec); + +void mm_iommu_init(struct mm_struct *mm) +{ + INIT_LIST_HEAD_RCU(&mm->context.iommu_group_mem_list); +} |