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1179 lines
31 KiB
1179 lines
31 KiB
/*
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* Copyright 2013 Red Hat Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* Authors: Jérôme Glisse <jglisse@redhat.com>
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*/
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/*
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* Refer to include/linux/hmm.h for information about heterogeneous memory
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* management or HMM for short.
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*/
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#include <linux/mm.h>
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#include <linux/hmm.h>
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#include <linux/init.h>
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#include <linux/rmap.h>
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#include <linux/swap.h>
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#include <linux/slab.h>
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#include <linux/sched.h>
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#include <linux/mmzone.h>
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#include <linux/pagemap.h>
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#include <linux/swapops.h>
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#include <linux/hugetlb.h>
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#include <linux/memremap.h>
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#include <linux/jump_label.h>
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#include <linux/mmu_notifier.h>
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#include <linux/memory_hotplug.h>
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#define PA_SECTION_SIZE (1UL << PA_SECTION_SHIFT)
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#if defined(CONFIG_DEVICE_PRIVATE) || defined(CONFIG_DEVICE_PUBLIC)
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/*
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* Device private memory see HMM (Documentation/vm/hmm.txt) or hmm.h
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*/
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DEFINE_STATIC_KEY_FALSE(device_private_key);
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EXPORT_SYMBOL(device_private_key);
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#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
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#if IS_ENABLED(CONFIG_HMM_MIRROR)
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static const struct mmu_notifier_ops hmm_mmu_notifier_ops;
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/*
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* struct hmm - HMM per mm struct
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*
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* @mm: mm struct this HMM struct is bound to
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* @lock: lock protecting ranges list
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* @sequence: we track updates to the CPU page table with a sequence number
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* @ranges: list of range being snapshotted
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* @mirrors: list of mirrors for this mm
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* @mmu_notifier: mmu notifier to track updates to CPU page table
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* @mirrors_sem: read/write semaphore protecting the mirrors list
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*/
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struct hmm {
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struct mm_struct *mm;
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spinlock_t lock;
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atomic_t sequence;
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struct list_head ranges;
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struct list_head mirrors;
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struct mmu_notifier mmu_notifier;
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struct rw_semaphore mirrors_sem;
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};
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/*
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* hmm_register - register HMM against an mm (HMM internal)
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*
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* @mm: mm struct to attach to
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*
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* This is not intended to be used directly by device drivers. It allocates an
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* HMM struct if mm does not have one, and initializes it.
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*/
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static struct hmm *hmm_register(struct mm_struct *mm)
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{
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struct hmm *hmm = READ_ONCE(mm->hmm);
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bool cleanup = false;
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/*
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* The hmm struct can only be freed once the mm_struct goes away,
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* hence we should always have pre-allocated an new hmm struct
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* above.
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*/
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if (hmm)
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return hmm;
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hmm = kmalloc(sizeof(*hmm), GFP_KERNEL);
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if (!hmm)
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return NULL;
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INIT_LIST_HEAD(&hmm->mirrors);
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init_rwsem(&hmm->mirrors_sem);
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atomic_set(&hmm->sequence, 0);
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hmm->mmu_notifier.ops = NULL;
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INIT_LIST_HEAD(&hmm->ranges);
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spin_lock_init(&hmm->lock);
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hmm->mm = mm;
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/*
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* We should only get here if hold the mmap_sem in write mode ie on
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* registration of first mirror through hmm_mirror_register()
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*/
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hmm->mmu_notifier.ops = &hmm_mmu_notifier_ops;
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if (__mmu_notifier_register(&hmm->mmu_notifier, mm)) {
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kfree(hmm);
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return NULL;
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}
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spin_lock(&mm->page_table_lock);
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if (!mm->hmm)
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mm->hmm = hmm;
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else
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cleanup = true;
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spin_unlock(&mm->page_table_lock);
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if (cleanup) {
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mmu_notifier_unregister(&hmm->mmu_notifier, mm);
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kfree(hmm);
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}
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return mm->hmm;
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}
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void hmm_mm_destroy(struct mm_struct *mm)
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{
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kfree(mm->hmm);
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}
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static void hmm_invalidate_range(struct hmm *hmm,
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enum hmm_update_type action,
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unsigned long start,
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unsigned long end)
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{
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struct hmm_mirror *mirror;
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struct hmm_range *range;
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spin_lock(&hmm->lock);
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list_for_each_entry(range, &hmm->ranges, list) {
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unsigned long addr, idx, npages;
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if (end < range->start || start >= range->end)
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continue;
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range->valid = false;
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addr = max(start, range->start);
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idx = (addr - range->start) >> PAGE_SHIFT;
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npages = (min(range->end, end) - addr) >> PAGE_SHIFT;
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memset(&range->pfns[idx], 0, sizeof(*range->pfns) * npages);
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}
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spin_unlock(&hmm->lock);
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down_read(&hmm->mirrors_sem);
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list_for_each_entry(mirror, &hmm->mirrors, list)
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mirror->ops->sync_cpu_device_pagetables(mirror, action,
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start, end);
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up_read(&hmm->mirrors_sem);
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}
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static void hmm_invalidate_range_start(struct mmu_notifier *mn,
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struct mm_struct *mm,
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unsigned long start,
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unsigned long end)
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{
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struct hmm *hmm = mm->hmm;
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VM_BUG_ON(!hmm);
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atomic_inc(&hmm->sequence);
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}
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static void hmm_invalidate_range_end(struct mmu_notifier *mn,
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struct mm_struct *mm,
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unsigned long start,
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unsigned long end)
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{
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struct hmm *hmm = mm->hmm;
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VM_BUG_ON(!hmm);
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hmm_invalidate_range(mm->hmm, HMM_UPDATE_INVALIDATE, start, end);
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}
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static const struct mmu_notifier_ops hmm_mmu_notifier_ops = {
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.invalidate_range_start = hmm_invalidate_range_start,
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.invalidate_range_end = hmm_invalidate_range_end,
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};
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/*
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* hmm_mirror_register() - register a mirror against an mm
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*
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* @mirror: new mirror struct to register
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* @mm: mm to register against
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*
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* To start mirroring a process address space, the device driver must register
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* an HMM mirror struct.
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*
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* THE mm->mmap_sem MUST BE HELD IN WRITE MODE !
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*/
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int hmm_mirror_register(struct hmm_mirror *mirror, struct mm_struct *mm)
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{
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/* Sanity check */
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if (!mm || !mirror || !mirror->ops)
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return -EINVAL;
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mirror->hmm = hmm_register(mm);
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if (!mirror->hmm)
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return -ENOMEM;
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down_write(&mirror->hmm->mirrors_sem);
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list_add(&mirror->list, &mirror->hmm->mirrors);
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up_write(&mirror->hmm->mirrors_sem);
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return 0;
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}
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EXPORT_SYMBOL(hmm_mirror_register);
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/*
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* hmm_mirror_unregister() - unregister a mirror
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*
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* @mirror: new mirror struct to register
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*
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* Stop mirroring a process address space, and cleanup.
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*/
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void hmm_mirror_unregister(struct hmm_mirror *mirror)
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{
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struct hmm *hmm = mirror->hmm;
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down_write(&hmm->mirrors_sem);
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list_del(&mirror->list);
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up_write(&hmm->mirrors_sem);
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}
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EXPORT_SYMBOL(hmm_mirror_unregister);
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struct hmm_vma_walk {
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struct hmm_range *range;
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unsigned long last;
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bool fault;
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bool block;
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bool write;
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};
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static int hmm_vma_do_fault(struct mm_walk *walk,
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unsigned long addr,
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hmm_pfn_t *pfn)
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{
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unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_REMOTE;
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struct hmm_vma_walk *hmm_vma_walk = walk->private;
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struct vm_area_struct *vma = walk->vma;
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int r;
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flags |= hmm_vma_walk->block ? 0 : FAULT_FLAG_ALLOW_RETRY;
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flags |= hmm_vma_walk->write ? FAULT_FLAG_WRITE : 0;
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r = handle_mm_fault(vma, addr, flags);
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if (r & VM_FAULT_RETRY)
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return -EBUSY;
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if (r & VM_FAULT_ERROR) {
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*pfn = HMM_PFN_ERROR;
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return -EFAULT;
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}
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return -EAGAIN;
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}
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static void hmm_pfns_special(hmm_pfn_t *pfns,
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unsigned long addr,
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unsigned long end)
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{
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for (; addr < end; addr += PAGE_SIZE, pfns++)
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*pfns = HMM_PFN_SPECIAL;
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}
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static int hmm_pfns_bad(unsigned long addr,
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unsigned long end,
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struct mm_walk *walk)
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{
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struct hmm_vma_walk *hmm_vma_walk = walk->private;
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struct hmm_range *range = hmm_vma_walk->range;
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hmm_pfn_t *pfns = range->pfns;
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unsigned long i;
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i = (addr - range->start) >> PAGE_SHIFT;
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for (; addr < end; addr += PAGE_SIZE, i++)
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pfns[i] = HMM_PFN_ERROR;
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return 0;
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}
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static void hmm_pfns_clear(hmm_pfn_t *pfns,
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unsigned long addr,
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unsigned long end)
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{
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for (; addr < end; addr += PAGE_SIZE, pfns++)
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*pfns = 0;
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}
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static int hmm_vma_walk_hole(unsigned long addr,
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unsigned long end,
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struct mm_walk *walk)
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{
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struct hmm_vma_walk *hmm_vma_walk = walk->private;
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struct hmm_range *range = hmm_vma_walk->range;
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hmm_pfn_t *pfns = range->pfns;
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unsigned long i;
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hmm_vma_walk->last = addr;
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i = (addr - range->start) >> PAGE_SHIFT;
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for (; addr < end; addr += PAGE_SIZE, i++) {
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pfns[i] = HMM_PFN_EMPTY;
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if (hmm_vma_walk->fault) {
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int ret;
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ret = hmm_vma_do_fault(walk, addr, &pfns[i]);
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if (ret != -EAGAIN)
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return ret;
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}
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}
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return hmm_vma_walk->fault ? -EAGAIN : 0;
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}
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static int hmm_vma_walk_clear(unsigned long addr,
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unsigned long end,
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struct mm_walk *walk)
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{
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struct hmm_vma_walk *hmm_vma_walk = walk->private;
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struct hmm_range *range = hmm_vma_walk->range;
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hmm_pfn_t *pfns = range->pfns;
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unsigned long i;
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hmm_vma_walk->last = addr;
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i = (addr - range->start) >> PAGE_SHIFT;
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for (; addr < end; addr += PAGE_SIZE, i++) {
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pfns[i] = 0;
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if (hmm_vma_walk->fault) {
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int ret;
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ret = hmm_vma_do_fault(walk, addr, &pfns[i]);
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if (ret != -EAGAIN)
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return ret;
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}
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}
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return hmm_vma_walk->fault ? -EAGAIN : 0;
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}
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static int hmm_vma_walk_pmd(pmd_t *pmdp,
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unsigned long start,
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unsigned long end,
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struct mm_walk *walk)
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{
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struct hmm_vma_walk *hmm_vma_walk = walk->private;
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struct hmm_range *range = hmm_vma_walk->range;
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struct vm_area_struct *vma = walk->vma;
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hmm_pfn_t *pfns = range->pfns;
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unsigned long addr = start, i;
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bool write_fault;
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hmm_pfn_t flag;
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pte_t *ptep;
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i = (addr - range->start) >> PAGE_SHIFT;
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flag = vma->vm_flags & VM_READ ? HMM_PFN_READ : 0;
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write_fault = hmm_vma_walk->fault & hmm_vma_walk->write;
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again:
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if (pmd_none(*pmdp))
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return hmm_vma_walk_hole(start, end, walk);
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if (pmd_huge(*pmdp) && vma->vm_flags & VM_HUGETLB)
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return hmm_pfns_bad(start, end, walk);
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if (pmd_devmap(*pmdp) || pmd_trans_huge(*pmdp)) {
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unsigned long pfn;
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pmd_t pmd;
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/*
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* No need to take pmd_lock here, even if some other threads
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* is splitting the huge pmd we will get that event through
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* mmu_notifier callback.
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*
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* So just read pmd value and check again its a transparent
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* huge or device mapping one and compute corresponding pfn
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* values.
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*/
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pmd = pmd_read_atomic(pmdp);
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barrier();
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if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd))
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goto again;
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if (pmd_protnone(pmd))
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return hmm_vma_walk_clear(start, end, walk);
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if (write_fault && !pmd_write(pmd))
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return hmm_vma_walk_clear(start, end, walk);
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pfn = pmd_pfn(pmd) + pte_index(addr);
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flag |= pmd_write(pmd) ? HMM_PFN_WRITE : 0;
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for (; addr < end; addr += PAGE_SIZE, i++, pfn++)
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pfns[i] = hmm_pfn_t_from_pfn(pfn) | flag;
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return 0;
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}
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if (pmd_bad(*pmdp))
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return hmm_pfns_bad(start, end, walk);
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ptep = pte_offset_map(pmdp, addr);
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for (; addr < end; addr += PAGE_SIZE, ptep++, i++) {
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pte_t pte = *ptep;
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pfns[i] = 0;
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|
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if (pte_none(pte)) {
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pfns[i] = HMM_PFN_EMPTY;
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if (hmm_vma_walk->fault)
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goto fault;
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continue;
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}
|
|
|
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if (!pte_present(pte)) {
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swp_entry_t entry;
|
|
|
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if (!non_swap_entry(entry)) {
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if (hmm_vma_walk->fault)
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goto fault;
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continue;
|
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}
|
|
|
|
entry = pte_to_swp_entry(pte);
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|
|
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/*
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* This is a special swap entry, ignore migration, use
|
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* device and report anything else as error.
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*/
|
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if (is_device_private_entry(entry)) {
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pfns[i] = hmm_pfn_t_from_pfn(swp_offset(entry));
|
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if (is_write_device_private_entry(entry)) {
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pfns[i] |= HMM_PFN_WRITE;
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} else if (write_fault)
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goto fault;
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pfns[i] |= HMM_PFN_DEVICE_UNADDRESSABLE;
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pfns[i] |= flag;
|
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} else if (is_migration_entry(entry)) {
|
|
if (hmm_vma_walk->fault) {
|
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pte_unmap(ptep);
|
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hmm_vma_walk->last = addr;
|
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migration_entry_wait(vma->vm_mm,
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pmdp, addr);
|
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return -EAGAIN;
|
|
}
|
|
continue;
|
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} else {
|
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/* Report error for everything else */
|
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pfns[i] = HMM_PFN_ERROR;
|
|
}
|
|
continue;
|
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}
|
|
|
|
if (write_fault && !pte_write(pte))
|
|
goto fault;
|
|
|
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pfns[i] = hmm_pfn_t_from_pfn(pte_pfn(pte)) | flag;
|
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pfns[i] |= pte_write(pte) ? HMM_PFN_WRITE : 0;
|
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continue;
|
|
|
|
fault:
|
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pte_unmap(ptep);
|
|
/* Fault all pages in range */
|
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return hmm_vma_walk_clear(start, end, walk);
|
|
}
|
|
pte_unmap(ptep - 1);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* hmm_vma_get_pfns() - snapshot CPU page table for a range of virtual addresses
|
|
* @vma: virtual memory area containing the virtual address range
|
|
* @range: used to track snapshot validity
|
|
* @start: range virtual start address (inclusive)
|
|
* @end: range virtual end address (exclusive)
|
|
* @entries: array of hmm_pfn_t: provided by the caller, filled in by function
|
|
* Returns: -EINVAL if invalid argument, -ENOMEM out of memory, 0 success
|
|
*
|
|
* This snapshots the CPU page table for a range of virtual addresses. Snapshot
|
|
* validity is tracked by range struct. See hmm_vma_range_done() for further
|
|
* information.
|
|
*
|
|
* The range struct is initialized here. It tracks the CPU page table, but only
|
|
* if the function returns success (0), in which case the caller must then call
|
|
* hmm_vma_range_done() to stop CPU page table update tracking on this range.
|
|
*
|
|
* NOT CALLING hmm_vma_range_done() IF FUNCTION RETURNS 0 WILL LEAD TO SERIOUS
|
|
* MEMORY CORRUPTION ! YOU HAVE BEEN WARNED !
|
|
*/
|
|
int hmm_vma_get_pfns(struct vm_area_struct *vma,
|
|
struct hmm_range *range,
|
|
unsigned long start,
|
|
unsigned long end,
|
|
hmm_pfn_t *pfns)
|
|
{
|
|
struct hmm_vma_walk hmm_vma_walk;
|
|
struct mm_walk mm_walk;
|
|
struct hmm *hmm;
|
|
|
|
/* FIXME support hugetlb fs */
|
|
if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) {
|
|
hmm_pfns_special(pfns, start, end);
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* Sanity check, this really should not happen ! */
|
|
if (start < vma->vm_start || start >= vma->vm_end)
|
|
return -EINVAL;
|
|
if (end < vma->vm_start || end > vma->vm_end)
|
|
return -EINVAL;
|
|
|
|
hmm = hmm_register(vma->vm_mm);
|
|
if (!hmm)
|
|
return -ENOMEM;
|
|
/* Caller must have registered a mirror, via hmm_mirror_register() ! */
|
|
if (!hmm->mmu_notifier.ops)
|
|
return -EINVAL;
|
|
|
|
/* Initialize range to track CPU page table update */
|
|
range->start = start;
|
|
range->pfns = pfns;
|
|
range->end = end;
|
|
spin_lock(&hmm->lock);
|
|
range->valid = true;
|
|
list_add_rcu(&range->list, &hmm->ranges);
|
|
spin_unlock(&hmm->lock);
|
|
|
|
hmm_vma_walk.fault = false;
|
|
hmm_vma_walk.range = range;
|
|
mm_walk.private = &hmm_vma_walk;
|
|
|
|
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.pmd_entry = hmm_vma_walk_pmd;
|
|
mm_walk.pte_hole = hmm_vma_walk_hole;
|
|
|
|
walk_page_range(start, end, &mm_walk);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(hmm_vma_get_pfns);
|
|
|
|
/*
|
|
* hmm_vma_range_done() - stop tracking change to CPU page table over a range
|
|
* @vma: virtual memory area containing the virtual address range
|
|
* @range: range being tracked
|
|
* Returns: false if range data has been invalidated, true otherwise
|
|
*
|
|
* Range struct is used to track updates to the CPU page table after a call to
|
|
* either hmm_vma_get_pfns() or hmm_vma_fault(). Once the device driver is done
|
|
* using the data, or wants to lock updates to the data it got from those
|
|
* functions, it must call the hmm_vma_range_done() function, which will then
|
|
* stop tracking CPU page table updates.
|
|
*
|
|
* Note that device driver must still implement general CPU page table update
|
|
* tracking either by using hmm_mirror (see hmm_mirror_register()) or by using
|
|
* the mmu_notifier API directly.
|
|
*
|
|
* CPU page table update tracking done through hmm_range is only temporary and
|
|
* to be used while trying to duplicate CPU page table contents for a range of
|
|
* virtual addresses.
|
|
*
|
|
* There are two ways to use this :
|
|
* again:
|
|
* hmm_vma_get_pfns(vma, range, start, end, pfns); or hmm_vma_fault(...);
|
|
* trans = device_build_page_table_update_transaction(pfns);
|
|
* device_page_table_lock();
|
|
* if (!hmm_vma_range_done(vma, range)) {
|
|
* device_page_table_unlock();
|
|
* goto again;
|
|
* }
|
|
* device_commit_transaction(trans);
|
|
* device_page_table_unlock();
|
|
*
|
|
* Or:
|
|
* hmm_vma_get_pfns(vma, range, start, end, pfns); or hmm_vma_fault(...);
|
|
* device_page_table_lock();
|
|
* hmm_vma_range_done(vma, range);
|
|
* device_update_page_table(pfns);
|
|
* device_page_table_unlock();
|
|
*/
|
|
bool hmm_vma_range_done(struct vm_area_struct *vma, struct hmm_range *range)
|
|
{
|
|
unsigned long npages = (range->end - range->start) >> PAGE_SHIFT;
|
|
struct hmm *hmm;
|
|
|
|
if (range->end <= range->start) {
|
|
BUG();
|
|
return false;
|
|
}
|
|
|
|
hmm = hmm_register(vma->vm_mm);
|
|
if (!hmm) {
|
|
memset(range->pfns, 0, sizeof(*range->pfns) * npages);
|
|
return false;
|
|
}
|
|
|
|
spin_lock(&hmm->lock);
|
|
list_del_rcu(&range->list);
|
|
spin_unlock(&hmm->lock);
|
|
|
|
return range->valid;
|
|
}
|
|
EXPORT_SYMBOL(hmm_vma_range_done);
|
|
|
|
/*
|
|
* hmm_vma_fault() - try to fault some address in a virtual address range
|
|
* @vma: virtual memory area containing the virtual address range
|
|
* @range: use to track pfns array content validity
|
|
* @start: fault range virtual start address (inclusive)
|
|
* @end: fault range virtual end address (exclusive)
|
|
* @pfns: array of hmm_pfn_t, only entry with fault flag set will be faulted
|
|
* @write: is it a write fault
|
|
* @block: allow blocking on fault (if true it sleeps and do not drop mmap_sem)
|
|
* Returns: 0 success, error otherwise (-EAGAIN means mmap_sem have been drop)
|
|
*
|
|
* 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.
|
|
*
|
|
* On error, for one virtual address in the range, the function will set the
|
|
* hmm_pfn_t error flag for the corresponding pfn entry.
|
|
*
|
|
* Expected use pattern:
|
|
* retry:
|
|
* down_read(&mm->mmap_sem);
|
|
* // Find vma and address device wants to fault, initialize hmm_pfn_t
|
|
* // array accordingly
|
|
* ret = hmm_vma_fault(vma, start, end, pfns, allow_retry);
|
|
* switch (ret) {
|
|
* case -EAGAIN:
|
|
* hmm_vma_range_done(vma, range);
|
|
* // You might want to rate limit or yield to play nicely, you may
|
|
* // also commit any valid pfn in the array assuming that you are
|
|
* // getting true from hmm_vma_range_monitor_end()
|
|
* goto retry;
|
|
* case 0:
|
|
* break;
|
|
* default:
|
|
* // Handle error !
|
|
* up_read(&mm->mmap_sem)
|
|
* return;
|
|
* }
|
|
* // Take device driver lock that serialize device page table update
|
|
* driver_lock_device_page_table_update();
|
|
* hmm_vma_range_done(vma, range);
|
|
* // Commit pfns we got from hmm_vma_fault()
|
|
* driver_unlock_device_page_table_update();
|
|
* up_read(&mm->mmap_sem)
|
|
*
|
|
* YOU MUST CALL hmm_vma_range_done() AFTER THIS FUNCTION RETURN SUCCESS (0)
|
|
* BEFORE FREEING THE range struct OR YOU WILL HAVE SERIOUS MEMORY CORRUPTION !
|
|
*
|
|
* YOU HAVE BEEN WARNED !
|
|
*/
|
|
int hmm_vma_fault(struct vm_area_struct *vma,
|
|
struct hmm_range *range,
|
|
unsigned long start,
|
|
unsigned long end,
|
|
hmm_pfn_t *pfns,
|
|
bool write,
|
|
bool block)
|
|
{
|
|
struct hmm_vma_walk hmm_vma_walk;
|
|
struct mm_walk mm_walk;
|
|
struct hmm *hmm;
|
|
int ret;
|
|
|
|
/* Sanity check, this really should not happen ! */
|
|
if (start < vma->vm_start || start >= vma->vm_end)
|
|
return -EINVAL;
|
|
if (end < vma->vm_start || end > vma->vm_end)
|
|
return -EINVAL;
|
|
|
|
hmm = hmm_register(vma->vm_mm);
|
|
if (!hmm) {
|
|
hmm_pfns_clear(pfns, start, end);
|
|
return -ENOMEM;
|
|
}
|
|
/* Caller must have registered a mirror using hmm_mirror_register() */
|
|
if (!hmm->mmu_notifier.ops)
|
|
return -EINVAL;
|
|
|
|
/* Initialize range to track CPU page table update */
|
|
range->start = start;
|
|
range->pfns = pfns;
|
|
range->end = end;
|
|
spin_lock(&hmm->lock);
|
|
range->valid = true;
|
|
list_add_rcu(&range->list, &hmm->ranges);
|
|
spin_unlock(&hmm->lock);
|
|
|
|
/* FIXME support hugetlb fs */
|
|
if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL)) {
|
|
hmm_pfns_special(pfns, start, end);
|
|
return 0;
|
|
}
|
|
|
|
hmm_vma_walk.fault = true;
|
|
hmm_vma_walk.write = write;
|
|
hmm_vma_walk.block = block;
|
|
hmm_vma_walk.range = range;
|
|
mm_walk.private = &hmm_vma_walk;
|
|
hmm_vma_walk.last = range->start;
|
|
|
|
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.pmd_entry = hmm_vma_walk_pmd;
|
|
mm_walk.pte_hole = hmm_vma_walk_hole;
|
|
|
|
do {
|
|
ret = walk_page_range(start, end, &mm_walk);
|
|
start = hmm_vma_walk.last;
|
|
} while (ret == -EAGAIN);
|
|
|
|
if (ret) {
|
|
unsigned long i;
|
|
|
|
i = (hmm_vma_walk.last - range->start) >> PAGE_SHIFT;
|
|
hmm_pfns_clear(&pfns[i], hmm_vma_walk.last, end);
|
|
hmm_vma_range_done(vma, range);
|
|
}
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(hmm_vma_fault);
|
|
#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);
|
|
percpu_ref_exit(ref);
|
|
}
|
|
|
|
static void hmm_devmem_ref_kill(void *data)
|
|
{
|
|
struct percpu_ref *ref = data;
|
|
struct hmm_devmem *devmem;
|
|
|
|
devmem = container_of(ref, struct hmm_devmem, ref);
|
|
percpu_ref_kill(ref);
|
|
wait_for_completion(&devmem->completion);
|
|
}
|
|
|
|
static int 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;
|
|
|
|
devmem->ops->free(devmem, page);
|
|
}
|
|
|
|
static DEFINE_MUTEX(hmm_devmem_lock);
|
|
static RADIX_TREE(hmm_devmem_radix, GFP_KERNEL);
|
|
|
|
static void hmm_devmem_radix_release(struct resource *resource)
|
|
{
|
|
resource_size_t key, align_start, align_size, align_end;
|
|
|
|
align_start = resource->start & ~(PA_SECTION_SIZE - 1);
|
|
align_size = ALIGN(resource_size(resource), PA_SECTION_SIZE);
|
|
align_end = align_start + align_size - 1;
|
|
|
|
mutex_lock(&hmm_devmem_lock);
|
|
for (key = resource->start;
|
|
key <= resource->end;
|
|
key += PA_SECTION_SIZE)
|
|
radix_tree_delete(&hmm_devmem_radix, key >> PA_SECTION_SHIFT);
|
|
mutex_unlock(&hmm_devmem_lock);
|
|
}
|
|
|
|
static void hmm_devmem_release(void *data)
|
|
{
|
|
struct hmm_devmem *devmem = data;
|
|
struct resource *resource = devmem->resource;
|
|
unsigned long start_pfn, npages;
|
|
struct zone *zone;
|
|
struct page *page;
|
|
|
|
/* pages are dead and unused, undo the arch mapping */
|
|
start_pfn = (resource->start & ~(PA_SECTION_SIZE - 1)) >> PAGE_SHIFT;
|
|
npages = ALIGN(resource_size(resource), PA_SECTION_SIZE) >> PAGE_SHIFT;
|
|
|
|
page = pfn_to_page(start_pfn);
|
|
zone = page_zone(page);
|
|
|
|
mem_hotplug_begin();
|
|
if (resource->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY)
|
|
__remove_pages(zone, start_pfn, npages);
|
|
else
|
|
arch_remove_memory(start_pfn << PAGE_SHIFT,
|
|
npages << PAGE_SHIFT);
|
|
mem_hotplug_done();
|
|
|
|
hmm_devmem_radix_release(resource);
|
|
}
|
|
|
|
static struct hmm_devmem *hmm_devmem_find(resource_size_t phys)
|
|
{
|
|
WARN_ON_ONCE(!rcu_read_lock_held());
|
|
|
|
return radix_tree_lookup(&hmm_devmem_radix, phys >> PA_SECTION_SHIFT);
|
|
}
|
|
|
|
static int hmm_devmem_pages_create(struct hmm_devmem *devmem)
|
|
{
|
|
resource_size_t key, align_start, align_size, align_end;
|
|
struct device *device = devmem->device;
|
|
int ret, nid, is_ram;
|
|
unsigned long pfn;
|
|
|
|
align_start = devmem->resource->start & ~(PA_SECTION_SIZE - 1);
|
|
align_size = ALIGN(devmem->resource->start +
|
|
resource_size(devmem->resource),
|
|
PA_SECTION_SIZE) - align_start;
|
|
|
|
is_ram = region_intersects(align_start, align_size,
|
|
IORESOURCE_SYSTEM_RAM,
|
|
IORES_DESC_NONE);
|
|
if (is_ram == REGION_MIXED) {
|
|
WARN_ONCE(1, "%s attempted on mixed region %pr\n",
|
|
__func__, devmem->resource);
|
|
return -ENXIO;
|
|
}
|
|
if (is_ram == REGION_INTERSECTS)
|
|
return -ENXIO;
|
|
|
|
if (devmem->resource->desc == IORES_DESC_DEVICE_PUBLIC_MEMORY)
|
|
devmem->pagemap.type = MEMORY_DEVICE_PUBLIC;
|
|
else
|
|
devmem->pagemap.type = MEMORY_DEVICE_PRIVATE;
|
|
|
|
devmem->pagemap.res = devmem->resource;
|
|
devmem->pagemap.page_fault = hmm_devmem_fault;
|
|
devmem->pagemap.page_free = hmm_devmem_free;
|
|
devmem->pagemap.dev = devmem->device;
|
|
devmem->pagemap.ref = &devmem->ref;
|
|
devmem->pagemap.data = devmem;
|
|
|
|
mutex_lock(&hmm_devmem_lock);
|
|
align_end = align_start + align_size - 1;
|
|
for (key = align_start; key <= align_end; key += PA_SECTION_SIZE) {
|
|
struct hmm_devmem *dup;
|
|
|
|
rcu_read_lock();
|
|
dup = hmm_devmem_find(key);
|
|
rcu_read_unlock();
|
|
if (dup) {
|
|
dev_err(device, "%s: collides with mapping for %s\n",
|
|
__func__, dev_name(dup->device));
|
|
mutex_unlock(&hmm_devmem_lock);
|
|
ret = -EBUSY;
|
|
goto error;
|
|
}
|
|
ret = radix_tree_insert(&hmm_devmem_radix,
|
|
key >> PA_SECTION_SHIFT,
|
|
devmem);
|
|
if (ret) {
|
|
dev_err(device, "%s: failed: %d\n", __func__, ret);
|
|
mutex_unlock(&hmm_devmem_lock);
|
|
goto error_radix;
|
|
}
|
|
}
|
|
mutex_unlock(&hmm_devmem_lock);
|
|
|
|
nid = dev_to_node(device);
|
|
if (nid < 0)
|
|
nid = numa_mem_id();
|
|
|
|
mem_hotplug_begin();
|
|
/*
|
|
* For device private memory we call add_pages() as we only need to
|
|
* allocate and initialize struct page for the device memory. More-
|
|
* over the device memory is un-accessible thus we do not want to
|
|
* create a linear mapping for the memory like arch_add_memory()
|
|
* would do.
|
|
*
|
|
* For device public memory, which is accesible by the CPU, we do
|
|
* want the linear mapping and thus use arch_add_memory().
|
|
*/
|
|
if (devmem->pagemap.type == MEMORY_DEVICE_PUBLIC)
|
|
ret = arch_add_memory(nid, align_start, align_size, false);
|
|
else
|
|
ret = add_pages(nid, align_start >> PAGE_SHIFT,
|
|
align_size >> PAGE_SHIFT, false);
|
|
if (ret) {
|
|
mem_hotplug_done();
|
|
goto error_add_memory;
|
|
}
|
|
move_pfn_range_to_zone(&NODE_DATA(nid)->node_zones[ZONE_DEVICE],
|
|
align_start >> PAGE_SHIFT,
|
|
align_size >> PAGE_SHIFT);
|
|
mem_hotplug_done();
|
|
|
|
for (pfn = devmem->pfn_first; pfn < devmem->pfn_last; pfn++) {
|
|
struct page *page = pfn_to_page(pfn);
|
|
|
|
page->pgmap = &devmem->pagemap;
|
|
}
|
|
return 0;
|
|
|
|
error_add_memory:
|
|
untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
|
|
error_radix:
|
|
hmm_devmem_radix_release(devmem->resource);
|
|
error:
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
int ret;
|
|
|
|
static_branch_enable(&device_private_key);
|
|
|
|
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);
|
|
|
|
ret = hmm_devmem_pages_create(devmem);
|
|
if (ret)
|
|
return ERR_PTR(ret);
|
|
|
|
ret = devm_add_action_or_reset(device, hmm_devmem_release, devmem);
|
|
if (ret)
|
|
return ERR_PTR(ret);
|
|
|
|
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;
|
|
int ret;
|
|
|
|
if (res->desc != IORES_DESC_DEVICE_PUBLIC_MEMORY)
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
static_branch_enable(&device_private_key);
|
|
|
|
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);
|
|
|
|
ret = hmm_devmem_pages_create(devmem);
|
|
if (ret)
|
|
return ERR_PTR(ret);
|
|
|
|
ret = devm_add_action_or_reset(device, hmm_devmem_release, devmem);
|
|
if (ret)
|
|
return ERR_PTR(ret);
|
|
|
|
ret = devm_add_action_or_reset(device, hmm_devmem_ref_kill,
|
|
&devmem->ref);
|
|
if (ret)
|
|
return ERR_PTR(ret);
|
|
|
|
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 */
|
|
|