| /* |
| * Copyright 2013 Red Hat Inc. |
| * |
| * 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. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * Authors: Jérôme Glisse <jglisse@redhat.com> |
| */ |
| /* |
| * Refer to include/linux/hmm.h for information about heterogeneous memory |
| * management or HMM for short. |
| */ |
| #include <linux/mm.h> |
| #include <linux/hmm.h> |
| #include <linux/init.h> |
| #include <linux/rmap.h> |
| #include <linux/swap.h> |
| #include <linux/slab.h> |
| #include <linux/sched.h> |
| #include <linux/mmzone.h> |
| #include <linux/pagemap.h> |
| #include <linux/swapops.h> |
| #include <linux/hugetlb.h> |
| #include <linux/memremap.h> |
| #include <linux/jump_label.h> |
| #include <linux/dma-mapping.h> |
| #include <linux/mmu_notifier.h> |
| #include <linux/memory_hotplug.h> |
| |
| #define PA_SECTION_SIZE (1UL << PA_SECTION_SHIFT) |
| |
| #if IS_ENABLED(CONFIG_HMM_MIRROR) |
| static const struct mmu_notifier_ops hmm_mmu_notifier_ops; |
| |
| static inline struct hmm *mm_get_hmm(struct mm_struct *mm) |
| { |
| struct hmm *hmm = READ_ONCE(mm->hmm); |
| |
| if (hmm && kref_get_unless_zero(&hmm->kref)) |
| return hmm; |
| |
| return NULL; |
| } |
| |
| /** |
| * hmm_get_or_create - register HMM against an mm (HMM internal) |
| * |
| * @mm: mm struct to attach to |
| * Returns: returns an HMM object, either by referencing the existing |
| * (per-process) object, or by creating a new one. |
| * |
| * This is not intended to be used directly by device drivers. If mm already |
| * has an HMM struct then it get a reference on it and returns it. Otherwise |
| * it allocates an HMM struct, initializes it, associate it with the mm and |
| * returns it. |
| */ |
| static struct hmm *hmm_get_or_create(struct mm_struct *mm) |
| { |
| struct hmm *hmm = mm_get_hmm(mm); |
| bool cleanup = false; |
| |
| if (hmm) |
| return hmm; |
| |
| hmm = kmalloc(sizeof(*hmm), GFP_KERNEL); |
| if (!hmm) |
| return NULL; |
| init_waitqueue_head(&hmm->wq); |
| INIT_LIST_HEAD(&hmm->mirrors); |
| init_rwsem(&hmm->mirrors_sem); |
| hmm->mmu_notifier.ops = NULL; |
| INIT_LIST_HEAD(&hmm->ranges); |
| mutex_init(&hmm->lock); |
| kref_init(&hmm->kref); |
| hmm->notifiers = 0; |
| hmm->dead = false; |
| hmm->mm = mm; |
| |
| spin_lock(&mm->page_table_lock); |
| if (!mm->hmm) |
| mm->hmm = hmm; |
| else |
| cleanup = true; |
| spin_unlock(&mm->page_table_lock); |
| |
| if (cleanup) |
| goto error; |
| |
| /* |
| * We should only get here if hold the mmap_sem in write mode ie on |
| * registration of first mirror through hmm_mirror_register() |
| */ |
| hmm->mmu_notifier.ops = &hmm_mmu_notifier_ops; |
| if (__mmu_notifier_register(&hmm->mmu_notifier, mm)) |
| goto error_mm; |
| |
| return hmm; |
| |
| error_mm: |
| spin_lock(&mm->page_table_lock); |
| if (mm->hmm == hmm) |
| mm->hmm = NULL; |
| spin_unlock(&mm->page_table_lock); |
| error: |
| kfree(hmm); |
| return NULL; |
| } |
| |
| static void hmm_free(struct kref *kref) |
| { |
| struct hmm *hmm = container_of(kref, struct hmm, kref); |
| struct mm_struct *mm = hmm->mm; |
| |
| mmu_notifier_unregister_no_release(&hmm->mmu_notifier, mm); |
| |
| spin_lock(&mm->page_table_lock); |
| if (mm->hmm == hmm) |
| mm->hmm = NULL; |
| spin_unlock(&mm->page_table_lock); |
| |
| kfree(hmm); |
| } |
| |
| static inline void hmm_put(struct hmm *hmm) |
| { |
| kref_put(&hmm->kref, hmm_free); |
| } |
| |
| void hmm_mm_destroy(struct mm_struct *mm) |
| { |
| struct hmm *hmm; |
| |
| spin_lock(&mm->page_table_lock); |
| hmm = mm_get_hmm(mm); |
| mm->hmm = NULL; |
| if (hmm) { |
| hmm->mm = NULL; |
| hmm->dead = true; |
| spin_unlock(&mm->page_table_lock); |
| hmm_put(hmm); |
| return; |
| } |
| |
| spin_unlock(&mm->page_table_lock); |
| } |
| |
| static void hmm_release(struct mmu_notifier *mn, struct mm_struct *mm) |
| { |
| struct hmm *hmm = mm_get_hmm(mm); |
| struct hmm_mirror *mirror; |
| struct hmm_range *range; |
| |
| /* Report this HMM as dying. */ |
| hmm->dead = true; |
| |
| /* Wake-up everyone waiting on any range. */ |
| mutex_lock(&hmm->lock); |
| list_for_each_entry(range, &hmm->ranges, list) { |
| range->valid = false; |
| } |
| wake_up_all(&hmm->wq); |
| mutex_unlock(&hmm->lock); |
| |
| down_write(&hmm->mirrors_sem); |
| mirror = list_first_entry_or_null(&hmm->mirrors, struct hmm_mirror, |
| list); |
| while (mirror) { |
| list_del_init(&mirror->list); |
| if (mirror->ops->release) { |
| /* |
| * Drop mirrors_sem so callback can wait on any pending |
| * work that might itself trigger mmu_notifier callback |
| * and thus would deadlock with us. |
| */ |
| up_write(&hmm->mirrors_sem); |
| mirror->ops->release(mirror); |
| down_write(&hmm->mirrors_sem); |
| } |
| mirror = list_first_entry_or_null(&hmm->mirrors, |
| struct hmm_mirror, list); |
| } |
| up_write(&hmm->mirrors_sem); |
| |
| hmm_put(hmm); |
| } |
| |
| static int hmm_invalidate_range_start(struct mmu_notifier *mn, |
| const struct mmu_notifier_range *nrange) |
| { |
| struct hmm *hmm = mm_get_hmm(nrange->mm); |
| struct hmm_mirror *mirror; |
| struct hmm_update update; |
| struct hmm_range *range; |
| int ret = 0; |
| |
| VM_BUG_ON(!hmm); |
| |
| update.start = nrange->start; |
| update.end = nrange->end; |
| update.event = HMM_UPDATE_INVALIDATE; |
| update.blockable = mmu_notifier_range_blockable(nrange); |
| |
| if (mmu_notifier_range_blockable(nrange)) |
| mutex_lock(&hmm->lock); |
| else if (!mutex_trylock(&hmm->lock)) { |
| ret = -EAGAIN; |
| goto out; |
| } |
| hmm->notifiers++; |
| list_for_each_entry(range, &hmm->ranges, list) { |
| if (update.end < range->start || update.start >= range->end) |
| continue; |
| |
| range->valid = false; |
| } |
| mutex_unlock(&hmm->lock); |
| |
| if (mmu_notifier_range_blockable(nrange)) |
| down_read(&hmm->mirrors_sem); |
| else if (!down_read_trylock(&hmm->mirrors_sem)) { |
| ret = -EAGAIN; |
| goto out; |
| } |
| list_for_each_entry(mirror, &hmm->mirrors, list) { |
| int ret; |
| |
| ret = mirror->ops->sync_cpu_device_pagetables(mirror, &update); |
| if (!update.blockable && ret == -EAGAIN) { |
| up_read(&hmm->mirrors_sem); |
| ret = -EAGAIN; |
| goto out; |
| } |
| } |
| up_read(&hmm->mirrors_sem); |
| |
| out: |
| hmm_put(hmm); |
| return ret; |
| } |
| |
| static void hmm_invalidate_range_end(struct mmu_notifier *mn, |
| const struct mmu_notifier_range *nrange) |
| { |
| struct hmm *hmm = mm_get_hmm(nrange->mm); |
| |
| VM_BUG_ON(!hmm); |
| |
| mutex_lock(&hmm->lock); |
| hmm->notifiers--; |
| if (!hmm->notifiers) { |
| struct hmm_range *range; |
| |
| list_for_each_entry(range, &hmm->ranges, list) { |
| if (range->valid) |
| continue; |
| range->valid = true; |
| } |
| wake_up_all(&hmm->wq); |
| } |
| mutex_unlock(&hmm->lock); |
| |
| hmm_put(hmm); |
| } |
| |
| static const struct mmu_notifier_ops hmm_mmu_notifier_ops = { |
| .release = hmm_release, |
| .invalidate_range_start = hmm_invalidate_range_start, |
| .invalidate_range_end = hmm_invalidate_range_end, |
| }; |
| |
| /* |
| * hmm_mirror_register() - register a mirror against an mm |
| * |
| * @mirror: new mirror struct to register |
| * @mm: mm to register against |
| * |
| * To start mirroring a process address space, the device driver must register |
| * an HMM mirror struct. |
| * |
| * THE mm->mmap_sem MUST BE HELD IN WRITE MODE ! |
| */ |
| int hmm_mirror_register(struct hmm_mirror *mirror, struct mm_struct *mm) |
| { |
| /* Sanity check */ |
| if (!mm || !mirror || !mirror->ops) |
| return -EINVAL; |
| |
| mirror->hmm = hmm_get_or_create(mm); |
| if (!mirror->hmm) |
| return -ENOMEM; |
| |
| down_write(&mirror->hmm->mirrors_sem); |
| list_add(&mirror->list, &mirror->hmm->mirrors); |
| up_write(&mirror->hmm->mirrors_sem); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(hmm_mirror_register); |
| |
| /* |
| * hmm_mirror_unregister() - unregister a mirror |
| * |
| * @mirror: new mirror struct to register |
| * |
| * Stop mirroring a process address space, and cleanup. |
| */ |
| void hmm_mirror_unregister(struct hmm_mirror *mirror) |
| { |
| struct hmm *hmm = READ_ONCE(mirror->hmm); |
| |
| if (hmm == NULL) |
| return; |
| |
| down_write(&hmm->mirrors_sem); |
| list_del_init(&mirror->list); |
| /* To protect us against double unregister ... */ |
| mirror->hmm = NULL; |
| up_write(&hmm->mirrors_sem); |
| |
| hmm_put(hmm); |
| } |
| EXPORT_SYMBOL(hmm_mirror_unregister); |
| |
| struct hmm_vma_walk { |
| struct hmm_range *range; |
| struct dev_pagemap *pgmap; |
| unsigned long last; |
| bool fault; |
| bool block; |
| }; |
| |
| static int hmm_vma_do_fault(struct mm_walk *walk, unsigned long addr, |
| bool write_fault, uint64_t *pfn) |
| { |
| unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_REMOTE; |
| struct hmm_vma_walk *hmm_vma_walk = walk->private; |
| struct hmm_range *range = hmm_vma_walk->range; |
| struct vm_area_struct *vma = walk->vma; |
| vm_fault_t ret; |
| |
| flags |= hmm_vma_walk->block ? 0 : FAULT_FLAG_ALLOW_RETRY; |
| flags |= write_fault ? FAULT_FLAG_WRITE : 0; |
| ret = handle_mm_fault(vma, addr, flags); |
| if (ret & VM_FAULT_RETRY) |
| return -EAGAIN; |
| if (ret & VM_FAULT_ERROR) { |
| *pfn = range->values[HMM_PFN_ERROR]; |
| return -EFAULT; |
| } |
| |
| return -EBUSY; |
| } |
| |
| static int hmm_pfns_bad(unsigned long addr, |
| unsigned long end, |
| struct mm_walk *walk) |
| { |
| struct hmm_vma_walk *hmm_vma_walk = walk->private; |
| struct hmm_range *range = hmm_vma_walk->range; |
| uint64_t *pfns = range->pfns; |
| unsigned long i; |
| |
| i = (addr - range->start) >> PAGE_SHIFT; |
| for (; addr < end; addr += PAGE_SIZE, i++) |
| pfns[i] = range->values[HMM_PFN_ERROR]; |
| |
| return 0; |
| } |
| |
| /* |
| * hmm_vma_walk_hole() - handle a range lacking valid pmd or pte(s) |
| * @start: range virtual start address (inclusive) |
| * @end: range virtual end address (exclusive) |
| * @fault: should we fault or not ? |
| * @write_fault: write fault ? |
| * @walk: mm_walk structure |
| * Returns: 0 on success, -EBUSY after page fault, or page fault error |
| * |
| * This function will be called whenever pmd_none() or pte_none() returns true, |
| * or whenever there is no page directory covering the virtual address range. |
| */ |
| static int hmm_vma_walk_hole_(unsigned long addr, unsigned long end, |
| bool fault, bool write_fault, |
| struct mm_walk *walk) |
| { |
| struct hmm_vma_walk *hmm_vma_walk = walk->private; |
| struct hmm_range *range = hmm_vma_walk->range; |
| uint64_t *pfns = range->pfns; |
| unsigned long i, page_size; |
| |
| hmm_vma_walk->last = addr; |
| page_size = hmm_range_page_size(range); |
| i = (addr - range->start) >> range->page_shift; |
| |
| for (; addr < end; addr += page_size, i++) { |
| pfns[i] = range->values[HMM_PFN_NONE]; |
| if (fault || write_fault) { |
| int ret; |
| |
| ret = hmm_vma_do_fault(walk, addr, write_fault, |
| &pfns[i]); |
| if (ret != -EBUSY) |
| return ret; |
| } |
| } |
| |
| return (fault || write_fault) ? -EBUSY : 0; |
| } |
| |
| static inline void hmm_pte_need_fault(const struct hmm_vma_walk *hmm_vma_walk, |
| uint64_t pfns, uint64_t cpu_flags, |
| bool *fault, bool *write_fault) |
| { |
| struct hmm_range *range = hmm_vma_walk->range; |
| |
| if (!hmm_vma_walk->fault) |
| return; |
| |
| /* |
| * So we not only consider the individual per page request we also |
| * consider the default flags requested for the range. The API can |
| * be use in 2 fashions. The first one where the HMM user coalesce |
| * multiple page fault into one request and set flags per pfns for |
| * of those faults. The second one where the HMM user want to pre- |
| * fault a range with specific flags. For the latter one it is a |
| * waste to have the user pre-fill the pfn arrays with a default |
| * flags value. |
| */ |
| pfns = (pfns & range->pfn_flags_mask) | range->default_flags; |
| |
| /* We aren't ask to do anything ... */ |
| if (!(pfns & range->flags[HMM_PFN_VALID])) |
| return; |
| /* If this is device memory than only fault if explicitly requested */ |
| if ((cpu_flags & range->flags[HMM_PFN_DEVICE_PRIVATE])) { |
| /* Do we fault on device memory ? */ |
| if (pfns & range->flags[HMM_PFN_DEVICE_PRIVATE]) { |
| *write_fault = pfns & range->flags[HMM_PFN_WRITE]; |
| *fault = true; |
| } |
| return; |
| } |
| |
| /* If CPU page table is not valid then we need to fault */ |
| *fault = !(cpu_flags & range->flags[HMM_PFN_VALID]); |
| /* Need to write fault ? */ |
| if ((pfns & range->flags[HMM_PFN_WRITE]) && |
| !(cpu_flags & range->flags[HMM_PFN_WRITE])) { |
| *write_fault = true; |
| *fault = true; |
| } |
| } |
| |
| static void hmm_range_need_fault(const struct hmm_vma_walk *hmm_vma_walk, |
| const uint64_t *pfns, unsigned long npages, |
| uint64_t cpu_flags, bool *fault, |
| bool *write_fault) |
| { |
| unsigned long i; |
| |
| if (!hmm_vma_walk->fault) { |
| *fault = *write_fault = false; |
| return; |
| } |
| |
| *fault = *write_fault = false; |
| for (i = 0; i < npages; ++i) { |
| hmm_pte_need_fault(hmm_vma_walk, pfns[i], cpu_flags, |
| fault, write_fault); |
| if ((*write_fault)) |
| return; |
| } |
| } |
| |
| static int hmm_vma_walk_hole(unsigned long addr, unsigned long end, |
| struct mm_walk *walk) |
| { |
| struct hmm_vma_walk *hmm_vma_walk = walk->private; |
| struct hmm_range *range = hmm_vma_walk->range; |
| bool fault, write_fault; |
| unsigned long i, npages; |
| uint64_t *pfns; |
| |
| i = (addr - range->start) >> PAGE_SHIFT; |
| npages = (end - addr) >> PAGE_SHIFT; |
| pfns = &range->pfns[i]; |
| hmm_range_need_fault(hmm_vma_walk, pfns, npages, |
| 0, &fault, &write_fault); |
| return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk); |
| } |
| |
| static inline uint64_t pmd_to_hmm_pfn_flags(struct hmm_range *range, pmd_t pmd) |
| { |
| if (pmd_protnone(pmd)) |
| return 0; |
| return pmd_write(pmd) ? range->flags[HMM_PFN_VALID] | |
| range->flags[HMM_PFN_WRITE] : |
| range->flags[HMM_PFN_VALID]; |
| } |
| |
| static inline uint64_t pud_to_hmm_pfn_flags(struct hmm_range *range, pud_t pud) |
| { |
| if (!pud_present(pud)) |
| return 0; |
| return pud_write(pud) ? range->flags[HMM_PFN_VALID] | |
| range->flags[HMM_PFN_WRITE] : |
| range->flags[HMM_PFN_VALID]; |
| } |
| |
| static int hmm_vma_handle_pmd(struct mm_walk *walk, |
| unsigned long addr, |
| unsigned long end, |
| uint64_t *pfns, |
| pmd_t pmd) |
| { |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| struct hmm_vma_walk *hmm_vma_walk = walk->private; |
| struct hmm_range *range = hmm_vma_walk->range; |
| unsigned long pfn, npages, i; |
| bool fault, write_fault; |
| uint64_t cpu_flags; |
| |
| npages = (end - addr) >> PAGE_SHIFT; |
| cpu_flags = pmd_to_hmm_pfn_flags(range, pmd); |
| hmm_range_need_fault(hmm_vma_walk, pfns, npages, cpu_flags, |
| &fault, &write_fault); |
| |
| if (pmd_protnone(pmd) || fault || write_fault) |
| return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk); |
| |
| pfn = pmd_pfn(pmd) + pte_index(addr); |
| for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++) { |
| if (pmd_devmap(pmd)) { |
| hmm_vma_walk->pgmap = get_dev_pagemap(pfn, |
| hmm_vma_walk->pgmap); |
| if (unlikely(!hmm_vma_walk->pgmap)) |
| return -EBUSY; |
| } |
| pfns[i] = hmm_device_entry_from_pfn(range, pfn) | cpu_flags; |
| } |
| if (hmm_vma_walk->pgmap) { |
| put_dev_pagemap(hmm_vma_walk->pgmap); |
| hmm_vma_walk->pgmap = NULL; |
| } |
| hmm_vma_walk->last = end; |
| return 0; |
| #else |
| /* If THP is not enabled then we should never reach that code ! */ |
| return -EINVAL; |
| #endif |
| } |
| |
| static inline uint64_t pte_to_hmm_pfn_flags(struct hmm_range *range, pte_t pte) |
| { |
| if (pte_none(pte) || !pte_present(pte)) |
| return 0; |
| return pte_write(pte) ? range->flags[HMM_PFN_VALID] | |
| range->flags[HMM_PFN_WRITE] : |
| range->flags[HMM_PFN_VALID]; |
| } |
| |
| static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, |
| unsigned long end, pmd_t *pmdp, pte_t *ptep, |
| uint64_t *pfn) |
| { |
| struct hmm_vma_walk *hmm_vma_walk = walk->private; |
| struct hmm_range *range = hmm_vma_walk->range; |
| struct vm_area_struct *vma = walk->vma; |
| bool fault, write_fault; |
| uint64_t cpu_flags; |
| pte_t pte = *ptep; |
| uint64_t orig_pfn = *pfn; |
| |
| *pfn = range->values[HMM_PFN_NONE]; |
| fault = write_fault = false; |
| |
| if (pte_none(pte)) { |
| hmm_pte_need_fault(hmm_vma_walk, orig_pfn, 0, |
| &fault, &write_fault); |
| if (fault || write_fault) |
| goto fault; |
| return 0; |
| } |
| |
| if (!pte_present(pte)) { |
| swp_entry_t entry = pte_to_swp_entry(pte); |
| |
| if (!non_swap_entry(entry)) { |
| if (fault || write_fault) |
| goto fault; |
| return 0; |
| } |
| |
| /* |
| * This is a special swap entry, ignore migration, use |
| * device and report anything else as error. |
| */ |
| if (is_device_private_entry(entry)) { |
| cpu_flags = range->flags[HMM_PFN_VALID] | |
| range->flags[HMM_PFN_DEVICE_PRIVATE]; |
| cpu_flags |= is_write_device_private_entry(entry) ? |
| range->flags[HMM_PFN_WRITE] : 0; |
| hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags, |
| &fault, &write_fault); |
| if (fault || write_fault) |
| goto fault; |
| *pfn = hmm_device_entry_from_pfn(range, |
| swp_offset(entry)); |
| *pfn |= cpu_flags; |
| return 0; |
| } |
| |
| if (is_migration_entry(entry)) { |
| if (fault || write_fault) { |
| pte_unmap(ptep); |
| hmm_vma_walk->last = addr; |
| migration_entry_wait(vma->vm_mm, |
| pmdp, addr); |
| return -EBUSY; |
| } |
| return 0; |
| } |
| |
| /* Report error for everything else */ |
| *pfn = range->values[HMM_PFN_ERROR]; |
| return -EFAULT; |
| } else { |
| cpu_flags = pte_to_hmm_pfn_flags(range, pte); |
| hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags, |
| &fault, &write_fault); |
| } |
| |
| if (fault || write_fault) |
| goto fault; |
| |
| if (pte_devmap(pte)) { |
| hmm_vma_walk->pgmap = get_dev_pagemap(pte_pfn(pte), |
| hmm_vma_walk->pgmap); |
| if (unlikely(!hmm_vma_walk->pgmap)) |
| return -EBUSY; |
| } else if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) && pte_special(pte)) { |
| *pfn = range->values[HMM_PFN_SPECIAL]; |
| return -EFAULT; |
| } |
| |
| *pfn = hmm_device_entry_from_pfn(range, pte_pfn(pte)) | cpu_flags; |
| return 0; |
| |
| fault: |
| if (hmm_vma_walk->pgmap) { |
| put_dev_pagemap(hmm_vma_walk->pgmap); |
| hmm_vma_walk->pgmap = NULL; |
| } |
| pte_unmap(ptep); |
| /* Fault any virtual address we were asked to fault */ |
| return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk); |
| } |
| |
| static int hmm_vma_walk_pmd(pmd_t *pmdp, |
| unsigned long start, |
| unsigned long end, |
| struct mm_walk *walk) |
| { |
| struct hmm_vma_walk *hmm_vma_walk = walk->private; |
| struct hmm_range *range = hmm_vma_walk->range; |
| struct vm_area_struct *vma = walk->vma; |
| uint64_t *pfns = range->pfns; |
| unsigned long addr = start, i; |
| pte_t *ptep; |
| pmd_t pmd; |
| |
| |
| again: |
| pmd = READ_ONCE(*pmdp); |
| if (pmd_none(pmd)) |
| return hmm_vma_walk_hole(start, end, walk); |
| |
| if (pmd_huge(pmd) && (range->vma->vm_flags & VM_HUGETLB)) |
| return hmm_pfns_bad(start, end, walk); |
| |
| if (thp_migration_supported() && is_pmd_migration_entry(pmd)) { |
| bool fault, write_fault; |
| unsigned long npages; |
| uint64_t *pfns; |
| |
| i = (addr - range->start) >> PAGE_SHIFT; |
| npages = (end - addr) >> PAGE_SHIFT; |
| pfns = &range->pfns[i]; |
| |
| hmm_range_need_fault(hmm_vma_walk, pfns, npages, |
| 0, &fault, &write_fault); |
| if (fault || write_fault) { |
| hmm_vma_walk->last = addr; |
| pmd_migration_entry_wait(vma->vm_mm, pmdp); |
| return -EBUSY; |
| } |
| return 0; |
| } else if (!pmd_present(pmd)) |
| return hmm_pfns_bad(start, end, walk); |
| |
| if (pmd_devmap(pmd) || pmd_trans_huge(pmd)) { |
| /* |
| * No need to take pmd_lock here, even if some other threads |
| * is splitting the huge pmd we will get that event through |
| * mmu_notifier callback. |
| * |
| * So just read pmd value and check again its a transparent |
| * huge or device mapping one and compute corresponding pfn |
| * values. |
| */ |
| pmd = pmd_read_atomic(pmdp); |
| barrier(); |
| if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd)) |
| goto again; |
| |
| i = (addr - range->start) >> PAGE_SHIFT; |
| return hmm_vma_handle_pmd(walk, addr, end, &pfns[i], pmd); |
| } |
| |
| /* |
| * We have handled all the valid case above ie either none, migration, |
| * huge or transparent huge. At this point either it is a valid pmd |
| * entry pointing to pte directory or it is a bad pmd that will not |
| * recover. |
| */ |
| if (pmd_bad(pmd)) |
| return hmm_pfns_bad(start, end, walk); |
| |
| ptep = pte_offset_map(pmdp, addr); |
| i = (addr - range->start) >> PAGE_SHIFT; |
| for (; addr < end; addr += PAGE_SIZE, ptep++, i++) { |
| int r; |
| |
| r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, &pfns[i]); |
| if (r) { |
| /* hmm_vma_handle_pte() did unmap pte directory */ |
| hmm_vma_walk->last = addr; |
| return r; |
| } |
| } |
| if (hmm_vma_walk->pgmap) { |
| /* |
| * We do put_dev_pagemap() here and not in hmm_vma_handle_pte() |
| * so that we can leverage get_dev_pagemap() optimization which |
| * will not re-take a reference on a pgmap if we already have |
| * one. |
| */ |
| put_dev_pagemap(hmm_vma_walk->pgmap); |
| hmm_vma_walk->pgmap = NULL; |
| } |
| pte_unmap(ptep - 1); |
| |
| hmm_vma_walk->last = addr; |
| return 0; |
| } |
| |
| static int hmm_vma_walk_pud(pud_t *pudp, |
| unsigned long start, |
| unsigned long end, |
| struct mm_walk *walk) |
| { |
| struct hmm_vma_walk *hmm_vma_walk = walk->private; |
| struct hmm_range *range = hmm_vma_walk->range; |
| unsigned long addr = start, next; |
| pmd_t *pmdp; |
| pud_t pud; |
| int ret; |
| |
| again: |
| pud = READ_ONCE(*pudp); |
| if (pud_none(pud)) |
| return hmm_vma_walk_hole(start, end, walk); |
| |
| if (pud_huge(pud) && pud_devmap(pud)) { |
| unsigned long i, npages, pfn; |
| uint64_t *pfns, cpu_flags; |
| bool fault, write_fault; |
| |
| if (!pud_present(pud)) |
| return hmm_vma_walk_hole(start, end, walk); |
| |
| i = (addr - range->start) >> PAGE_SHIFT; |
| npages = (end - addr) >> PAGE_SHIFT; |
| pfns = &range->pfns[i]; |
| |
| cpu_flags = pud_to_hmm_pfn_flags(range, pud); |
| hmm_range_need_fault(hmm_vma_walk, pfns, npages, |
| cpu_flags, &fault, &write_fault); |
| if (fault || write_fault) |
| return hmm_vma_walk_hole_(addr, end, fault, |
| write_fault, walk); |
| |
| #ifdef CONFIG_HUGETLB_PAGE |
| pfn = pud_pfn(pud) + ((addr & ~PUD_MASK) >> PAGE_SHIFT); |
| for (i = 0; i < npages; ++i, ++pfn) { |
| hmm_vma_walk->pgmap = get_dev_pagemap(pfn, |
| hmm_vma_walk->pgmap); |
| if (unlikely(!hmm_vma_walk->pgmap)) |
| return -EBUSY; |
| pfns[i] = hmm_device_entry_from_pfn(range, pfn) | |
| cpu_flags; |
| } |
| if (hmm_vma_walk->pgmap) { |
| put_dev_pagemap(hmm_vma_walk->pgmap); |
| hmm_vma_walk->pgmap = NULL; |
| } |
| hmm_vma_walk->last = end; |
| return 0; |
| #else |
| return -EINVAL; |
| #endif |
| } |
| |
| split_huge_pud(walk->vma, pudp, addr); |
| if (pud_none(*pudp)) |
| goto again; |
| |
| pmdp = pmd_offset(pudp, addr); |
| do { |
| next = pmd_addr_end(addr, end); |
| ret = hmm_vma_walk_pmd(pmdp, addr, next, walk); |
| if (ret) |
| return ret; |
| } while (pmdp++, addr = next, addr != end); |
| |
| return 0; |
| } |
| |
| static int hmm_vma_walk_hugetlb_entry(pte_t *pte, unsigned long hmask, |
| unsigned long start, unsigned long end, |
| struct mm_walk *walk) |
| { |
| #ifdef CONFIG_HUGETLB_PAGE |
| unsigned long addr = start, i, pfn, mask, size, pfn_inc; |
| struct hmm_vma_walk *hmm_vma_walk = walk->private; |
| struct hmm_range *range = hmm_vma_walk->range; |
| struct vm_area_struct *vma = walk->vma; |
| struct hstate *h = hstate_vma(vma); |
| uint64_t orig_pfn, cpu_flags; |
| bool fault, write_fault; |
| spinlock_t *ptl; |
| pte_t entry; |
| int ret = 0; |
| |
| size = 1UL << huge_page_shift(h); |
| mask = size - 1; |
| if (range->page_shift != PAGE_SHIFT) { |
| /* Make sure we are looking at full page. */ |
| if (start & mask) |
| return -EINVAL; |
| if (end < (start + size)) |
| return -EINVAL; |
| pfn_inc = size >> PAGE_SHIFT; |
| } else { |
| pfn_inc = 1; |
| size = PAGE_SIZE; |
| } |
| |
| |
| ptl = huge_pte_lock(hstate_vma(walk->vma), walk->mm, pte); |
| entry = huge_ptep_get(pte); |
| |
| i = (start - range->start) >> range->page_shift; |
| orig_pfn = range->pfns[i]; |
| range->pfns[i] = range->values[HMM_PFN_NONE]; |
| cpu_flags = pte_to_hmm_pfn_flags(range, entry); |
| fault = write_fault = false; |
| hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags, |
| &fault, &write_fault); |
| if (fault || write_fault) { |
| ret = -ENOENT; |
| goto unlock; |
| } |
| |
| pfn = pte_pfn(entry) + ((start & mask) >> range->page_shift); |
| for (; addr < end; addr += size, i++, pfn += pfn_inc) |
| range->pfns[i] = hmm_device_entry_from_pfn(range, pfn) | |
| cpu_flags; |
| hmm_vma_walk->last = end; |
| |
| unlock: |
| spin_unlock(ptl); |
| |
| if (ret == -ENOENT) |
| return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk); |
| |
| return ret; |
| #else /* CONFIG_HUGETLB_PAGE */ |
| return -EINVAL; |
| #endif |
| } |
| |
| static void hmm_pfns_clear(struct hmm_range *range, |
| uint64_t *pfns, |
| unsigned long addr, |
| unsigned long end) |
| { |
| for (; addr < end; addr += PAGE_SIZE, pfns++) |
| *pfns = range->values[HMM_PFN_NONE]; |
| } |
| |
| /* |
| * hmm_range_register() - start tracking change to CPU page table over a range |
| * @range: range |
| * @mm: the mm struct for the range of virtual address |
| * @start: start virtual address (inclusive) |
| * @end: end virtual address (exclusive) |
| * @page_shift: expect page shift for the range |
| * Returns 0 on success, -EFAULT if the address space is no longer valid |
| * |
| * Track updates to the CPU page table see include/linux/hmm.h |
| */ |
| int hmm_range_register(struct hmm_range *range, |
| struct mm_struct *mm, |
| unsigned long start, |
| unsigned long end, |
| unsigned page_shift) |
| { |
| unsigned long mask = ((1UL << page_shift) - 1UL); |
| |
| range->valid = false; |
| range->hmm = NULL; |
| |
| if ((start & mask) || (end & mask)) |
| return -EINVAL; |
| if (start >= end) |
| return -EINVAL; |
| |
| range->page_shift = page_shift; |
| range->start = start; |
| range->end = end; |
| |
| range->hmm = hmm_get_or_create(mm); |
| if (!range->hmm) |
| return -EFAULT; |
| |
| /* Check if hmm_mm_destroy() was call. */ |
| if (range->hmm->mm == NULL || range->hmm->dead) { |
| hmm_put(range->hmm); |
| return -EFAULT; |
| } |
| |
| /* Initialize range to track CPU page table update */ |
| mutex_lock(&range->hmm->lock); |
| |
| list_add_rcu(&range->list, &range->hmm->ranges); |
| |
| /* |
| * If there are any concurrent notifiers we have to wait for them for |
| * the range to be valid (see hmm_range_wait_until_valid()). |
| */ |
| if (!range->hmm->notifiers) |
| range->valid = true; |
| mutex_unlock(&range->hmm->lock); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL(hmm_range_register); |
| |
| /* |
| * hmm_range_unregister() - stop tracking change to CPU page table over a range |
| * @range: range |
| * |
| * Range struct is used to track updates to the CPU page table after a call to |
| * hmm_range_register(). See include/linux/hmm.h for how to use it. |
| */ |
| void hmm_range_unregister(struct hmm_range *range) |
| { |
| /* Sanity check this really should not happen. */ |
| if (range->hmm == NULL || range->end <= range->start) |
| return; |
| |
| mutex_lock(&range->hmm->lock); |
| list_del_rcu(&range->list); |
| mutex_unlock(&range->hmm->lock); |
| |
| /* Drop reference taken by hmm_range_register() */ |
| range->valid = false; |
| hmm_put(range->hmm); |
| range->hmm = NULL; |
| } |
| EXPORT_SYMBOL(hmm_range_unregister); |
| |
| /* |
| * hmm_range_snapshot() - snapshot CPU page table for a range |
| * @range: range |
| * Returns: -EINVAL if invalid argument, -ENOMEM out of memory, -EPERM invalid |
| * permission (for instance asking for write and range is read only), |
| * -EAGAIN if you need to retry, -EFAULT invalid (ie either no valid |
| * vma or it is illegal to access that range), number of valid pages |
| * in range->pfns[] (from range start address). |
| * |
| * This snapshots the CPU page table for a range of virtual addresses. Snapshot |
| * validity is tracked by range struct. See in include/linux/hmm.h for example |
| * on how to use. |
| */ |
| long hmm_range_snapshot(struct hmm_range *range) |
| { |
| const unsigned long device_vma = VM_IO | VM_PFNMAP | VM_MIXEDMAP; |
| unsigned long start = range->start, end; |
| struct hmm_vma_walk hmm_vma_walk; |
| struct hmm *hmm = range->hmm; |
| struct vm_area_struct *vma; |
| struct mm_walk mm_walk; |
| |
| /* Check if hmm_mm_destroy() was call. */ |
| if (hmm->mm == NULL || hmm->dead) |
| return -EFAULT; |
| |
| do { |
| /* If range is no longer valid force retry. */ |
| if (!range->valid) |
| return -EAGAIN; |
| |
| vma = find_vma(hmm->mm, start); |
| if (vma == NULL || (vma->vm_flags & device_vma)) |
| return -EFAULT; |
| |
| if (is_vm_hugetlb_page(vma)) { |
| struct hstate *h = hstate_vma(vma); |
| |
| if (huge_page_shift(h) != range->page_shift && |
| range->page_shift != PAGE_SHIFT) |
| return -EINVAL; |
| } else { |
| if (range->page_shift != PAGE_SHIFT) |
| return -EINVAL; |
| } |
| |
| if (!(vma->vm_flags & VM_READ)) { |
| /* |
| * If vma do not allow read access, then assume that it |
| * does not allow write access, either. HMM does not |
| * support architecture that allow write without read. |
| */ |
| hmm_pfns_clear(range, range->pfns, |
| range->start, range->end); |
| return -EPERM; |
| } |
| |
| range->vma = vma; |
| hmm_vma_walk.pgmap = NULL; |
| hmm_vma_walk.last = start; |
| hmm_vma_walk.fault = false; |
| hmm_vma_walk.range = range; |
| mm_walk.private = &hmm_vma_walk; |
| end = min(range->end, vma->vm_end); |
| |
| mm_walk.vma = vma; |
| mm_walk.mm = vma->vm_mm; |
| mm_walk.pte_entry = NULL; |
| mm_walk.test_walk = NULL; |
| mm_walk.hugetlb_entry = NULL; |
| mm_walk.pud_entry = hmm_vma_walk_pud; |
| mm_walk.pmd_entry = hmm_vma_walk_pmd; |
| mm_walk.pte_hole = hmm_vma_walk_hole; |
| mm_walk.hugetlb_entry = hmm_vma_walk_hugetlb_entry; |
| |
| walk_page_range(start, end, &mm_walk); |
| start = end; |
| } while (start < range->end); |
| |
| return (hmm_vma_walk.last - range->start) >> PAGE_SHIFT; |
| } |
| EXPORT_SYMBOL(hmm_range_snapshot); |
| |
| /* |
| * hmm_range_fault() - try to fault some address in a virtual address range |
| * @range: range being faulted |
| * @block: allow blocking on fault (if true it sleeps and do not drop mmap_sem) |
| * Returns: number of valid pages in range->pfns[] (from range start |
| * address). This may be zero. If the return value is negative, |
| * then one of the following values may be returned: |
| * |
| * -EINVAL invalid arguments or mm or virtual address are in an |
| * invalid vma (for instance device file vma). |
| * -ENOMEM: Out of memory. |
| * -EPERM: Invalid permission (for instance asking for write and |
| * range is read only). |
| * -EAGAIN: If you need to retry and mmap_sem was drop. This can only |
| * happens if block argument is false. |
| * -EBUSY: If the the range is being invalidated and you should wait |
| * for invalidation to finish. |
| * -EFAULT: Invalid (ie either no valid vma or it is illegal to access |
| * that range), number of valid pages in range->pfns[] (from |
| * range start address). |
| * |
| * This is similar to a regular CPU page fault except that it will not trigger |
| * any memory migration if the memory being faulted is not accessible by CPUs |
| * and caller does not ask for migration. |
| * |
| * On error, for one virtual address in the range, the function will mark the |
| * corresponding HMM pfn entry with an error flag. |
| */ |
| long hmm_range_fault(struct hmm_range *range, bool block) |
| { |
| const unsigned long device_vma = VM_IO | VM_PFNMAP | VM_MIXEDMAP; |
| unsigned long start = range->start, end; |
| struct hmm_vma_walk hmm_vma_walk; |
| struct hmm *hmm = range->hmm; |
| struct vm_area_struct *vma; |
| struct mm_walk mm_walk; |
| int ret; |
| |
| /* Check if hmm_mm_destroy() was call. */ |
| if (hmm->mm == NULL || hmm->dead) |
| return -EFAULT; |
| |
| do { |
| /* If range is no longer valid force retry. */ |
| if (!range->valid) { |
| up_read(&hmm->mm->mmap_sem); |
| return -EAGAIN; |
| } |
| |
| vma = find_vma(hmm->mm, start); |
| if (vma == NULL || (vma->vm_flags & device_vma)) |
| return -EFAULT; |
| |
| if (is_vm_hugetlb_page(vma)) { |
| if (huge_page_shift(hstate_vma(vma)) != |
| range->page_shift && |
| range->page_shift != PAGE_SHIFT) |
| return -EINVAL; |
| } else { |
| if (range->page_shift != PAGE_SHIFT) |
| return -EINVAL; |
| } |
| |
| if (!(vma->vm_flags & VM_READ)) { |
| /* |
| * If vma do not allow read access, then assume that it |
| * does not allow write access, either. HMM does not |
| * support architecture that allow write without read. |
| */ |
| hmm_pfns_clear(range, range->pfns, |
| range->start, range->end); |
| return -EPERM; |
| } |
| |
| range->vma = vma; |
| hmm_vma_walk.pgmap = NULL; |
| hmm_vma_walk.last = start; |
| hmm_vma_walk.fault = true; |
| hmm_vma_walk.block = block; |
| hmm_vma_walk.range = range; |
| mm_walk.private = &hmm_vma_walk; |
| end = min(range->end, vma->vm_end); |
| |
| mm_walk.vma = vma; |
| mm_walk.mm = vma->vm_mm; |
| mm_walk.pte_entry = NULL; |
| mm_walk.test_walk = NULL; |
| mm_walk.hugetlb_entry = NULL; |
| mm_walk.pud_entry = hmm_vma_walk_pud; |
| mm_walk.pmd_entry = hmm_vma_walk_pmd; |
| mm_walk.pte_hole = hmm_vma_walk_hole; |
| mm_walk.hugetlb_entry = hmm_vma_walk_hugetlb_entry; |
| |
| do { |
| ret = walk_page_range(start, end, &mm_walk); |
| start = hmm_vma_walk.last; |
| |
| /* Keep trying while the range is valid. */ |
| } while (ret == -EBUSY && range->valid); |
| |
| if (ret) { |
| unsigned long i; |
| |
| i = (hmm_vma_walk.last - range->start) >> PAGE_SHIFT; |
| hmm_pfns_clear(range, &range->pfns[i], |
| hmm_vma_walk.last, range->end); |
| return ret; |
| } |
| start = end; |
| |
| } while (start < range->end); |
| |
| return (hmm_vma_walk.last - range->start) >> PAGE_SHIFT; |
| } |
| EXPORT_SYMBOL(hmm_range_fault); |
| |
| /** |
| * hmm_range_dma_map() - hmm_range_fault() and dma map page all in one. |
| * @range: range being faulted |
| * @device: device against to dma map page to |
| * @daddrs: dma address of mapped pages |
| * @block: allow blocking on fault (if true it sleeps and do not drop mmap_sem) |
| * Returns: number of pages mapped on success, -EAGAIN if mmap_sem have been |
| * drop and you need to try again, some other error value otherwise |
| * |
| * Note same usage pattern as hmm_range_fault(). |
| */ |
| long hmm_range_dma_map(struct hmm_range *range, |
| struct device *device, |
| dma_addr_t *daddrs, |
| bool block) |
| { |
| unsigned long i, npages, mapped; |
| long ret; |
| |
| ret = hmm_range_fault(range, block); |
| if (ret <= 0) |
| return ret ? ret : -EBUSY; |
| |
| npages = (range->end - range->start) >> PAGE_SHIFT; |
| for (i = 0, mapped = 0; i < npages; ++i) { |
| enum dma_data_direction dir = DMA_TO_DEVICE; |
| struct page *page; |
| |
| /* |
| * FIXME need to update DMA API to provide invalid DMA address |
| * value instead of a function to test dma address value. This |
| * would remove lot of dumb code duplicated accross many arch. |
| * |
| * For now setting it to 0 here is good enough as the pfns[] |
| * value is what is use to check what is valid and what isn't. |
| */ |
| daddrs[i] = 0; |
| |
| page = hmm_device_entry_to_page(range, range->pfns[i]); |
| if (page == NULL) |
| continue; |
| |
| /* Check if range is being invalidated */ |
| if (!range->valid) { |
| ret = -EBUSY; |
| goto unmap; |
| } |
| |
| /* If it is read and write than map bi-directional. */ |
| if (range->pfns[i] & range->flags[HMM_PFN_WRITE]) |
| dir = DMA_BIDIRECTIONAL; |
| |
| daddrs[i] = dma_map_page(device, page, 0, PAGE_SIZE, dir); |
| if (dma_mapping_error(device, daddrs[i])) { |
| ret = -EFAULT; |
| goto unmap; |
| } |
| |
| mapped++; |
| } |
| |
| return mapped; |
| |
| unmap: |
| for (npages = i, i = 0; (i < npages) && mapped; ++i) { |
| enum dma_data_direction dir = DMA_TO_DEVICE; |
| struct page *page; |
| |
| page = hmm_device_entry_to_page(range, range->pfns[i]); |
| if (page == NULL) |
| continue; |
| |
| if (dma_mapping_error(device, daddrs[i])) |
| continue; |
| |
| /* If it is read and write than map bi-directional. */ |
| if (range->pfns[i] & range->flags[HMM_PFN_WRITE]) |
| dir = DMA_BIDIRECTIONAL; |
| |
| dma_unmap_page(device, daddrs[i], PAGE_SIZE, dir); |
| mapped--; |
| } |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(hmm_range_dma_map); |
| |
| /** |
| * hmm_range_dma_unmap() - unmap range of that was map with hmm_range_dma_map() |
| * @range: range being unmapped |
| * @vma: the vma against which the range (optional) |
| * @device: device against which dma map was done |
| * @daddrs: dma address of mapped pages |
| * @dirty: dirty page if it had the write flag set |
| * Returns: number of page unmapped on success, -EINVAL otherwise |
| * |
| * Note that caller MUST abide by mmu notifier or use HMM mirror and abide |
| * to the sync_cpu_device_pagetables() callback so that it is safe here to |
| * call set_page_dirty(). Caller must also take appropriate locks to avoid |
| * concurrent mmu notifier or sync_cpu_device_pagetables() to make progress. |
| */ |
| long hmm_range_dma_unmap(struct hmm_range *range, |
| struct vm_area_struct *vma, |
| struct device *device, |
| dma_addr_t *daddrs, |
| bool dirty) |
| { |
| unsigned long i, npages; |
| long cpages = 0; |
| |
| /* Sanity check. */ |
| if (range->end <= range->start) |
| return -EINVAL; |
| if (!daddrs) |
| return -EINVAL; |
| if (!range->pfns) |
| return -EINVAL; |
| |
| npages = (range->end - range->start) >> PAGE_SHIFT; |
| for (i = 0; i < npages; ++i) { |
| enum dma_data_direction dir = DMA_TO_DEVICE; |
| struct page *page; |
| |
| page = hmm_device_entry_to_page(range, range->pfns[i]); |
| if (page == NULL) |
| continue; |
| |
| /* If it is read and write than map bi-directional. */ |
| if (range->pfns[i] & range->flags[HMM_PFN_WRITE]) { |
| dir = DMA_BIDIRECTIONAL; |
| |
| /* |
| * See comments in function description on why it is |
| * safe here to call set_page_dirty() |
| */ |
| if (dirty) |
| set_page_dirty(page); |
| } |
| |
| /* Unmap and clear pfns/dma address */ |
| dma_unmap_page(device, daddrs[i], PAGE_SIZE, dir); |
| range->pfns[i] = range->values[HMM_PFN_NONE]; |
| /* FIXME see comments in hmm_vma_dma_map() */ |
| daddrs[i] = 0; |
| cpages++; |
| } |
| |
| return cpages; |
| } |
| EXPORT_SYMBOL(hmm_range_dma_unmap); |
| #endif /* IS_ENABLED(CONFIG_HMM_MIRROR) */ |
| |
| |
| #if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC) |
| struct page *hmm_vma_alloc_locked_page(struct vm_area_struct *vma, |
| unsigned long addr) |
| { |
| struct page *page; |
| |
| page = alloc_page_vma(GFP_HIGHUSER, vma, addr); |
| if (!page) |
| return NULL; |
| lock_page(page); |
| return page; |
| } |
| EXPORT_SYMBOL(hmm_vma_alloc_locked_page); |
| |
| |
| static void hmm_devmem_ref_release(struct percpu_ref *ref) |
| { |
| struct hmm_devmem *devmem; |
| |
| devmem = container_of(ref, struct hmm_devmem, ref); |
| complete(&devmem->completion); |
| } |
| |
| static void hmm_devmem_ref_exit(void *data) |
| { |
| struct percpu_ref *ref = data; |
| struct hmm_devmem *devmem; |
| |
| devmem = container_of(ref, struct hmm_devmem, ref); |
| wait_for_completion(&devmem->completion); |
| percpu_ref_exit(ref); |
| } |
| |
| static void hmm_devmem_ref_kill(struct percpu_ref *ref) |
| { |
| percpu_ref_kill(ref); |
| } |
| |
| static vm_fault_t hmm_devmem_fault(struct vm_area_struct *vma, |
| unsigned long addr, |
| const struct page *page, |
| unsigned int flags, |
| pmd_t *pmdp) |
| { |
| struct hmm_devmem *devmem = page->pgmap->data; |
| |
| return devmem->ops->fault(devmem, vma, addr, page, flags, pmdp); |
| } |
| |
| static void hmm_devmem_free(struct page *page, void *data) |
| { |
| struct hmm_devmem *devmem = data; |
| |
| page->mapping = NULL; |
| |
| devmem->ops->free(devmem, page); |
| } |
| |
| /* |
| * hmm_devmem_add() - hotplug ZONE_DEVICE memory for device memory |
| * |
| * @ops: memory event device driver callback (see struct hmm_devmem_ops) |
| * @device: device struct to bind the resource too |
| * @size: size in bytes of the device memory to add |
| * Returns: pointer to new hmm_devmem struct ERR_PTR otherwise |
| * |
| * This function first finds an empty range of physical address big enough to |
| * contain the new resource, and then hotplugs it as ZONE_DEVICE memory, which |
| * in turn allocates struct pages. It does not do anything beyond that; all |
| * events affecting the memory will go through the various callbacks provided |
| * by hmm_devmem_ops struct. |
| * |
| * Device driver should call this function during device initialization and |
| * is then responsible of memory management. HMM only provides helpers. |
| */ |
| struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops, |
| struct device *device, |
| unsigned long size) |
| { |
| struct hmm_devmem *devmem; |
| resource_size_t addr; |
| void *result; |
| int ret; |
| |
| dev_pagemap_get_ops(); |
| |
| devmem = devm_kzalloc(device, sizeof(*devmem), GFP_KERNEL); |
| if (!devmem) |
| return ERR_PTR(-ENOMEM); |
| |
| init_completion(&devmem->completion); |
| devmem->pfn_first = -1UL; |
| devmem->pfn_last = -1UL; |
| devmem->resource = NULL; |
| devmem->device = device; |
| devmem->ops = ops; |
| |
| ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release, |
| 0, GFP_KERNEL); |
| if (ret) |
| return ERR_PTR(ret); |
| |
| ret = devm_add_action_or_reset(device, hmm_devmem_ref_exit, &devmem->ref); |
| if (ret) |
| return ERR_PTR(ret); |
| |
| size = ALIGN(size, PA_SECTION_SIZE); |
| addr = min((unsigned long)iomem_resource.end, |
| (1UL << MAX_PHYSMEM_BITS) - 1); |
| addr = addr - size + 1UL; |
| |
| /* |
| * FIXME add a new helper to quickly walk resource tree and find free |
| * range |
| * |
| * FIXME what about ioport_resource resource ? |
| */ |
| for (; addr > size && addr >= iomem_resource.start; addr -= size) { |
| ret = region_intersects(addr, size, 0, IORES_DESC_NONE); |
| if (ret != REGION_DISJOINT) |
| continue; |
| |
| devmem->resource = devm_request_mem_region(device, addr, size, |
| dev_name(device)); |
| if (!devmem->resource) |
| return ERR_PTR(-ENOMEM); |
| break; |
| } |
| if (!devmem->resource) |
| return ERR_PTR(-ERANGE); |
| |
| devmem->resource->desc = IORES_DESC_DEVICE_PRIVATE_MEMORY; |
| devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT; |
| devmem->pfn_last = devmem->pfn_first + |
| (resource_size(devmem->resource) >> PAGE_SHIFT); |
| devmem->page_fault = hmm_devmem_fault; |
| |
| devmem->pagemap.type = MEMORY_DEVICE_PRIVATE; |
| devmem->pagemap.res = *devmem->resource; |
| devmem->pagemap.page_free = hmm_devmem_free; |
| devmem->pagemap.altmap_valid = false; |
| devmem->pagemap.ref = &devmem->ref; |
| devmem->pagemap.data = devmem; |
| devmem->pagemap.kill = hmm_devmem_ref_kill; |
| |
| result = devm_memremap_pages(devmem->device, &devmem->pagemap); |
| if (IS_ERR(result)) |
| return result; |
| return devmem; |
| } |
| EXPORT_SYMBOL_GPL(hmm_devmem_add); |
| |
| struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops, |
| struct device *device, |
| struct resource *res) |
| { |
| struct hmm_devmem *devmem; |
| void *result; |
| int ret; |
| |
| if (res->desc != IORES_DESC_DEVICE_PUBLIC_MEMORY) |
| return ERR_PTR(-EINVAL); |
| |
| dev_pagemap_get_ops(); |
| |
| devmem = devm_kzalloc(device, sizeof(*devmem), GFP_KERNEL); |
| if (!devmem) |
| return ERR_PTR(-ENOMEM); |
| |
| init_completion(&devmem->completion); |
| devmem->pfn_first = -1UL; |
| devmem->pfn_last = -1UL; |
| devmem->resource = res; |
| devmem->device = device; |
| devmem->ops = ops; |
| |
| ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release, |
| 0, GFP_KERNEL); |
| if (ret) |
| return ERR_PTR(ret); |
| |
| ret = devm_add_action_or_reset(device, hmm_devmem_ref_exit, |
| &devmem->ref); |
| if (ret) |
| return ERR_PTR(ret); |
| |
| devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT; |
| devmem->pfn_last = devmem->pfn_first + |
| (resource_size(devmem->resource) >> PAGE_SHIFT); |
| devmem->page_fault = hmm_devmem_fault; |
| |
| devmem->pagemap.type = MEMORY_DEVICE_PUBLIC; |
| devmem->pagemap.res = *devmem->resource; |
| devmem->pagemap.page_free = hmm_devmem_free; |
| devmem->pagemap.altmap_valid = false; |
| devmem->pagemap.ref = &devmem->ref; |
| devmem->pagemap.data = devmem; |
| devmem->pagemap.kill = hmm_devmem_ref_kill; |
| |
| result = devm_memremap_pages(devmem->device, &devmem->pagemap); |
| if (IS_ERR(result)) |
| return result; |
| return devmem; |
| } |
| EXPORT_SYMBOL_GPL(hmm_devmem_add_resource); |
| |
| /* |
| * A device driver that wants to handle multiple devices memory through a |
| * single fake device can use hmm_device to do so. This is purely a helper |
| * and it is not needed to make use of any HMM functionality. |
| */ |
| #define HMM_DEVICE_MAX 256 |
| |
| static DECLARE_BITMAP(hmm_device_mask, HMM_DEVICE_MAX); |
| static DEFINE_SPINLOCK(hmm_device_lock); |
| static struct class *hmm_device_class; |
| static dev_t hmm_device_devt; |
| |
| static void hmm_device_release(struct device *device) |
| { |
| struct hmm_device *hmm_device; |
| |
| hmm_device = container_of(device, struct hmm_device, device); |
| spin_lock(&hmm_device_lock); |
| clear_bit(hmm_device->minor, hmm_device_mask); |
| spin_unlock(&hmm_device_lock); |
| |
| kfree(hmm_device); |
| } |
| |
| struct hmm_device *hmm_device_new(void *drvdata) |
| { |
| struct hmm_device *hmm_device; |
| |
| hmm_device = kzalloc(sizeof(*hmm_device), GFP_KERNEL); |
| if (!hmm_device) |
| return ERR_PTR(-ENOMEM); |
| |
| spin_lock(&hmm_device_lock); |
| hmm_device->minor = find_first_zero_bit(hmm_device_mask, HMM_DEVICE_MAX); |
| if (hmm_device->minor >= HMM_DEVICE_MAX) { |
| spin_unlock(&hmm_device_lock); |
| kfree(hmm_device); |
| return ERR_PTR(-EBUSY); |
| } |
| set_bit(hmm_device->minor, hmm_device_mask); |
| spin_unlock(&hmm_device_lock); |
| |
| dev_set_name(&hmm_device->device, "hmm_device%d", hmm_device->minor); |
| hmm_device->device.devt = MKDEV(MAJOR(hmm_device_devt), |
| hmm_device->minor); |
| hmm_device->device.release = hmm_device_release; |
| dev_set_drvdata(&hmm_device->device, drvdata); |
| hmm_device->device.class = hmm_device_class; |
| device_initialize(&hmm_device->device); |
| |
| return hmm_device; |
| } |
| EXPORT_SYMBOL(hmm_device_new); |
| |
| void hmm_device_put(struct hmm_device *hmm_device) |
| { |
| put_device(&hmm_device->device); |
| } |
| EXPORT_SYMBOL(hmm_device_put); |
| |
| static int __init hmm_init(void) |
| { |
| int ret; |
| |
| ret = alloc_chrdev_region(&hmm_device_devt, 0, |
| HMM_DEVICE_MAX, |
| "hmm_device"); |
| if (ret) |
| return ret; |
| |
| hmm_device_class = class_create(THIS_MODULE, "hmm_device"); |
| if (IS_ERR(hmm_device_class)) { |
| unregister_chrdev_region(hmm_device_devt, HMM_DEVICE_MAX); |
| return PTR_ERR(hmm_device_class); |
| } |
| return 0; |
| } |
| |
| device_initcall(hmm_init); |
| #endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */ |