1133ff0eaSJérôme Glisse /* 2133ff0eaSJérôme Glisse * Copyright 2013 Red Hat Inc. 3133ff0eaSJérôme Glisse * 4133ff0eaSJérôme Glisse * This program is free software; you can redistribute it and/or modify 5133ff0eaSJérôme Glisse * it under the terms of the GNU General Public License as published by 6133ff0eaSJérôme Glisse * the Free Software Foundation; either version 2 of the License, or 7133ff0eaSJérôme Glisse * (at your option) any later version. 8133ff0eaSJérôme Glisse * 9133ff0eaSJérôme Glisse * This program is distributed in the hope that it will be useful, 10133ff0eaSJérôme Glisse * but WITHOUT ANY WARRANTY; without even the implied warranty of 11133ff0eaSJérôme Glisse * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12133ff0eaSJérôme Glisse * GNU General Public License for more details. 13133ff0eaSJérôme Glisse * 14f813f219SJérôme Glisse * Authors: Jérôme Glisse <jglisse@redhat.com> 15133ff0eaSJérôme Glisse */ 16133ff0eaSJérôme Glisse /* 17133ff0eaSJérôme Glisse * Refer to include/linux/hmm.h for information about heterogeneous memory 18133ff0eaSJérôme Glisse * management or HMM for short. 19133ff0eaSJérôme Glisse */ 20133ff0eaSJérôme Glisse #include <linux/mm.h> 21133ff0eaSJérôme Glisse #include <linux/hmm.h> 22858b54daSJérôme Glisse #include <linux/init.h> 23da4c3c73SJérôme Glisse #include <linux/rmap.h> 24da4c3c73SJérôme Glisse #include <linux/swap.h> 25133ff0eaSJérôme Glisse #include <linux/slab.h> 26133ff0eaSJérôme Glisse #include <linux/sched.h> 274ef589dcSJérôme Glisse #include <linux/mmzone.h> 284ef589dcSJérôme Glisse #include <linux/pagemap.h> 29da4c3c73SJérôme Glisse #include <linux/swapops.h> 30da4c3c73SJérôme Glisse #include <linux/hugetlb.h> 314ef589dcSJérôme Glisse #include <linux/memremap.h> 327b2d55d2SJérôme Glisse #include <linux/jump_label.h> 33c0b12405SJérôme Glisse #include <linux/mmu_notifier.h> 344ef589dcSJérôme Glisse #include <linux/memory_hotplug.h> 354ef589dcSJérôme Glisse 364ef589dcSJérôme Glisse #define PA_SECTION_SIZE (1UL << PA_SECTION_SHIFT) 37133ff0eaSJérôme Glisse 386b368cd4SJérôme Glisse #if IS_ENABLED(CONFIG_HMM_MIRROR) 39c0b12405SJérôme Glisse static const struct mmu_notifier_ops hmm_mmu_notifier_ops; 40c0b12405SJérôme Glisse 41133ff0eaSJérôme Glisse /* 42133ff0eaSJérôme Glisse * struct hmm - HMM per mm struct 43133ff0eaSJérôme Glisse * 44133ff0eaSJérôme Glisse * @mm: mm struct this HMM struct is bound to 45da4c3c73SJérôme Glisse * @lock: lock protecting ranges list 46c0b12405SJérôme Glisse * @sequence: we track updates to the CPU page table with a sequence number 47da4c3c73SJérôme Glisse * @ranges: list of range being snapshotted 48c0b12405SJérôme Glisse * @mirrors: list of mirrors for this mm 49c0b12405SJérôme Glisse * @mmu_notifier: mmu notifier to track updates to CPU page table 50c0b12405SJérôme Glisse * @mirrors_sem: read/write semaphore protecting the mirrors list 51133ff0eaSJérôme Glisse */ 52133ff0eaSJérôme Glisse struct hmm { 53133ff0eaSJérôme Glisse struct mm_struct *mm; 54da4c3c73SJérôme Glisse spinlock_t lock; 55c0b12405SJérôme Glisse atomic_t sequence; 56da4c3c73SJérôme Glisse struct list_head ranges; 57c0b12405SJérôme Glisse struct list_head mirrors; 58c0b12405SJérôme Glisse struct mmu_notifier mmu_notifier; 59c0b12405SJérôme Glisse struct rw_semaphore mirrors_sem; 60133ff0eaSJérôme Glisse }; 61133ff0eaSJérôme Glisse 62133ff0eaSJérôme Glisse /* 63133ff0eaSJérôme Glisse * hmm_register - register HMM against an mm (HMM internal) 64133ff0eaSJérôme Glisse * 65133ff0eaSJérôme Glisse * @mm: mm struct to attach to 66133ff0eaSJérôme Glisse * 67133ff0eaSJérôme Glisse * This is not intended to be used directly by device drivers. It allocates an 68133ff0eaSJérôme Glisse * HMM struct if mm does not have one, and initializes it. 69133ff0eaSJérôme Glisse */ 70133ff0eaSJérôme Glisse static struct hmm *hmm_register(struct mm_struct *mm) 71133ff0eaSJérôme Glisse { 72c0b12405SJérôme Glisse struct hmm *hmm = READ_ONCE(mm->hmm); 73c0b12405SJérôme Glisse bool cleanup = false; 74133ff0eaSJérôme Glisse 75133ff0eaSJérôme Glisse /* 76133ff0eaSJérôme Glisse * The hmm struct can only be freed once the mm_struct goes away, 77133ff0eaSJérôme Glisse * hence we should always have pre-allocated an new hmm struct 78133ff0eaSJérôme Glisse * above. 79133ff0eaSJérôme Glisse */ 80c0b12405SJérôme Glisse if (hmm) 81c0b12405SJérôme Glisse return hmm; 82c0b12405SJérôme Glisse 83c0b12405SJérôme Glisse hmm = kmalloc(sizeof(*hmm), GFP_KERNEL); 84c0b12405SJérôme Glisse if (!hmm) 85c0b12405SJérôme Glisse return NULL; 86c0b12405SJérôme Glisse INIT_LIST_HEAD(&hmm->mirrors); 87c0b12405SJérôme Glisse init_rwsem(&hmm->mirrors_sem); 88c0b12405SJérôme Glisse atomic_set(&hmm->sequence, 0); 89c0b12405SJérôme Glisse hmm->mmu_notifier.ops = NULL; 90da4c3c73SJérôme Glisse INIT_LIST_HEAD(&hmm->ranges); 91da4c3c73SJérôme Glisse spin_lock_init(&hmm->lock); 92c0b12405SJérôme Glisse hmm->mm = mm; 93c0b12405SJérôme Glisse 94c0b12405SJérôme Glisse spin_lock(&mm->page_table_lock); 95c0b12405SJérôme Glisse if (!mm->hmm) 96c0b12405SJérôme Glisse mm->hmm = hmm; 97c0b12405SJérôme Glisse else 98c0b12405SJérôme Glisse cleanup = true; 99c0b12405SJérôme Glisse spin_unlock(&mm->page_table_lock); 100c0b12405SJérôme Glisse 101*86a2d598SRalph Campbell if (cleanup) 102*86a2d598SRalph Campbell goto error; 103*86a2d598SRalph Campbell 104*86a2d598SRalph Campbell /* 105*86a2d598SRalph Campbell * We should only get here if hold the mmap_sem in write mode ie on 106*86a2d598SRalph Campbell * registration of first mirror through hmm_mirror_register() 107*86a2d598SRalph Campbell */ 108*86a2d598SRalph Campbell hmm->mmu_notifier.ops = &hmm_mmu_notifier_ops; 109*86a2d598SRalph Campbell if (__mmu_notifier_register(&hmm->mmu_notifier, mm)) 110*86a2d598SRalph Campbell goto error_mm; 111c0b12405SJérôme Glisse 112133ff0eaSJérôme Glisse return mm->hmm; 113*86a2d598SRalph Campbell 114*86a2d598SRalph Campbell error_mm: 115*86a2d598SRalph Campbell spin_lock(&mm->page_table_lock); 116*86a2d598SRalph Campbell if (mm->hmm == hmm) 117*86a2d598SRalph Campbell mm->hmm = NULL; 118*86a2d598SRalph Campbell spin_unlock(&mm->page_table_lock); 119*86a2d598SRalph Campbell error: 120*86a2d598SRalph Campbell kfree(hmm); 121*86a2d598SRalph Campbell return NULL; 122133ff0eaSJérôme Glisse } 123133ff0eaSJérôme Glisse 124133ff0eaSJérôme Glisse void hmm_mm_destroy(struct mm_struct *mm) 125133ff0eaSJérôme Glisse { 126133ff0eaSJérôme Glisse kfree(mm->hmm); 127133ff0eaSJérôme Glisse } 128c0b12405SJérôme Glisse 129c0b12405SJérôme Glisse static void hmm_invalidate_range(struct hmm *hmm, 130c0b12405SJérôme Glisse enum hmm_update_type action, 131c0b12405SJérôme Glisse unsigned long start, 132c0b12405SJérôme Glisse unsigned long end) 133c0b12405SJérôme Glisse { 134c0b12405SJérôme Glisse struct hmm_mirror *mirror; 135da4c3c73SJérôme Glisse struct hmm_range *range; 136da4c3c73SJérôme Glisse 137da4c3c73SJérôme Glisse spin_lock(&hmm->lock); 138da4c3c73SJérôme Glisse list_for_each_entry(range, &hmm->ranges, list) { 139da4c3c73SJérôme Glisse unsigned long addr, idx, npages; 140da4c3c73SJérôme Glisse 141da4c3c73SJérôme Glisse if (end < range->start || start >= range->end) 142da4c3c73SJérôme Glisse continue; 143da4c3c73SJérôme Glisse 144da4c3c73SJérôme Glisse range->valid = false; 145da4c3c73SJérôme Glisse addr = max(start, range->start); 146da4c3c73SJérôme Glisse idx = (addr - range->start) >> PAGE_SHIFT; 147da4c3c73SJérôme Glisse npages = (min(range->end, end) - addr) >> PAGE_SHIFT; 148da4c3c73SJérôme Glisse memset(&range->pfns[idx], 0, sizeof(*range->pfns) * npages); 149da4c3c73SJérôme Glisse } 150da4c3c73SJérôme Glisse spin_unlock(&hmm->lock); 151c0b12405SJérôme Glisse 152c0b12405SJérôme Glisse down_read(&hmm->mirrors_sem); 153c0b12405SJérôme Glisse list_for_each_entry(mirror, &hmm->mirrors, list) 154c0b12405SJérôme Glisse mirror->ops->sync_cpu_device_pagetables(mirror, action, 155c0b12405SJérôme Glisse start, end); 156c0b12405SJérôme Glisse up_read(&hmm->mirrors_sem); 157c0b12405SJérôme Glisse } 158c0b12405SJérôme Glisse 159e1401513SRalph Campbell static void hmm_release(struct mmu_notifier *mn, struct mm_struct *mm) 160e1401513SRalph Campbell { 161e1401513SRalph Campbell struct hmm_mirror *mirror; 162e1401513SRalph Campbell struct hmm *hmm = mm->hmm; 163e1401513SRalph Campbell 164e1401513SRalph Campbell down_write(&hmm->mirrors_sem); 165e1401513SRalph Campbell mirror = list_first_entry_or_null(&hmm->mirrors, struct hmm_mirror, 166e1401513SRalph Campbell list); 167e1401513SRalph Campbell while (mirror) { 168e1401513SRalph Campbell list_del_init(&mirror->list); 169e1401513SRalph Campbell if (mirror->ops->release) { 170e1401513SRalph Campbell /* 171e1401513SRalph Campbell * Drop mirrors_sem so callback can wait on any pending 172e1401513SRalph Campbell * work that might itself trigger mmu_notifier callback 173e1401513SRalph Campbell * and thus would deadlock with us. 174e1401513SRalph Campbell */ 175e1401513SRalph Campbell up_write(&hmm->mirrors_sem); 176e1401513SRalph Campbell mirror->ops->release(mirror); 177e1401513SRalph Campbell down_write(&hmm->mirrors_sem); 178e1401513SRalph Campbell } 179e1401513SRalph Campbell mirror = list_first_entry_or_null(&hmm->mirrors, 180e1401513SRalph Campbell struct hmm_mirror, list); 181e1401513SRalph Campbell } 182e1401513SRalph Campbell up_write(&hmm->mirrors_sem); 183e1401513SRalph Campbell } 184e1401513SRalph Campbell 18593065ac7SMichal Hocko static int hmm_invalidate_range_start(struct mmu_notifier *mn, 186c0b12405SJérôme Glisse struct mm_struct *mm, 187c0b12405SJérôme Glisse unsigned long start, 18893065ac7SMichal Hocko unsigned long end, 18993065ac7SMichal Hocko bool blockable) 190c0b12405SJérôme Glisse { 191c0b12405SJérôme Glisse struct hmm *hmm = mm->hmm; 192c0b12405SJérôme Glisse 193c0b12405SJérôme Glisse VM_BUG_ON(!hmm); 194c0b12405SJérôme Glisse 195c0b12405SJérôme Glisse atomic_inc(&hmm->sequence); 19693065ac7SMichal Hocko 19793065ac7SMichal Hocko return 0; 198c0b12405SJérôme Glisse } 199c0b12405SJérôme Glisse 200c0b12405SJérôme Glisse static void hmm_invalidate_range_end(struct mmu_notifier *mn, 201c0b12405SJérôme Glisse struct mm_struct *mm, 202c0b12405SJérôme Glisse unsigned long start, 203c0b12405SJérôme Glisse unsigned long end) 204c0b12405SJérôme Glisse { 205c0b12405SJérôme Glisse struct hmm *hmm = mm->hmm; 206c0b12405SJérôme Glisse 207c0b12405SJérôme Glisse VM_BUG_ON(!hmm); 208c0b12405SJérôme Glisse 209c0b12405SJérôme Glisse hmm_invalidate_range(mm->hmm, HMM_UPDATE_INVALIDATE, start, end); 210c0b12405SJérôme Glisse } 211c0b12405SJérôme Glisse 212c0b12405SJérôme Glisse static const struct mmu_notifier_ops hmm_mmu_notifier_ops = { 213e1401513SRalph Campbell .release = hmm_release, 214c0b12405SJérôme Glisse .invalidate_range_start = hmm_invalidate_range_start, 215c0b12405SJérôme Glisse .invalidate_range_end = hmm_invalidate_range_end, 216c0b12405SJérôme Glisse }; 217c0b12405SJérôme Glisse 218c0b12405SJérôme Glisse /* 219c0b12405SJérôme Glisse * hmm_mirror_register() - register a mirror against an mm 220c0b12405SJérôme Glisse * 221c0b12405SJérôme Glisse * @mirror: new mirror struct to register 222c0b12405SJérôme Glisse * @mm: mm to register against 223c0b12405SJérôme Glisse * 224c0b12405SJérôme Glisse * To start mirroring a process address space, the device driver must register 225c0b12405SJérôme Glisse * an HMM mirror struct. 226c0b12405SJérôme Glisse * 227c0b12405SJérôme Glisse * THE mm->mmap_sem MUST BE HELD IN WRITE MODE ! 228c0b12405SJérôme Glisse */ 229c0b12405SJérôme Glisse int hmm_mirror_register(struct hmm_mirror *mirror, struct mm_struct *mm) 230c0b12405SJérôme Glisse { 231c0b12405SJérôme Glisse /* Sanity check */ 232c0b12405SJérôme Glisse if (!mm || !mirror || !mirror->ops) 233c0b12405SJérôme Glisse return -EINVAL; 234c0b12405SJérôme Glisse 235c01cbba2SJérôme Glisse again: 236c0b12405SJérôme Glisse mirror->hmm = hmm_register(mm); 237c0b12405SJérôme Glisse if (!mirror->hmm) 238c0b12405SJérôme Glisse return -ENOMEM; 239c0b12405SJérôme Glisse 240c0b12405SJérôme Glisse down_write(&mirror->hmm->mirrors_sem); 241c01cbba2SJérôme Glisse if (mirror->hmm->mm == NULL) { 242c01cbba2SJérôme Glisse /* 243c01cbba2SJérôme Glisse * A racing hmm_mirror_unregister() is about to destroy the hmm 244c01cbba2SJérôme Glisse * struct. Try again to allocate a new one. 245c01cbba2SJérôme Glisse */ 246c01cbba2SJérôme Glisse up_write(&mirror->hmm->mirrors_sem); 247c01cbba2SJérôme Glisse mirror->hmm = NULL; 248c01cbba2SJérôme Glisse goto again; 249c01cbba2SJérôme Glisse } else { 250c0b12405SJérôme Glisse list_add(&mirror->list, &mirror->hmm->mirrors); 251c0b12405SJérôme Glisse up_write(&mirror->hmm->mirrors_sem); 252c01cbba2SJérôme Glisse } 253c0b12405SJérôme Glisse 254c0b12405SJérôme Glisse return 0; 255c0b12405SJérôme Glisse } 256c0b12405SJérôme Glisse EXPORT_SYMBOL(hmm_mirror_register); 257c0b12405SJérôme Glisse 258c0b12405SJérôme Glisse /* 259c0b12405SJérôme Glisse * hmm_mirror_unregister() - unregister a mirror 260c0b12405SJérôme Glisse * 261c0b12405SJérôme Glisse * @mirror: new mirror struct to register 262c0b12405SJérôme Glisse * 263c0b12405SJérôme Glisse * Stop mirroring a process address space, and cleanup. 264c0b12405SJérôme Glisse */ 265c0b12405SJérôme Glisse void hmm_mirror_unregister(struct hmm_mirror *mirror) 266c0b12405SJérôme Glisse { 267c01cbba2SJérôme Glisse bool should_unregister = false; 268c01cbba2SJérôme Glisse struct mm_struct *mm; 269c01cbba2SJérôme Glisse struct hmm *hmm; 270c0b12405SJérôme Glisse 271c01cbba2SJérôme Glisse if (mirror->hmm == NULL) 272c01cbba2SJérôme Glisse return; 273c01cbba2SJérôme Glisse 274c01cbba2SJérôme Glisse hmm = mirror->hmm; 275c0b12405SJérôme Glisse down_write(&hmm->mirrors_sem); 276e1401513SRalph Campbell list_del_init(&mirror->list); 277c01cbba2SJérôme Glisse should_unregister = list_empty(&hmm->mirrors); 278c01cbba2SJérôme Glisse mirror->hmm = NULL; 279c01cbba2SJérôme Glisse mm = hmm->mm; 280c01cbba2SJérôme Glisse hmm->mm = NULL; 281c0b12405SJérôme Glisse up_write(&hmm->mirrors_sem); 282c01cbba2SJérôme Glisse 283c01cbba2SJérôme Glisse if (!should_unregister || mm == NULL) 284c01cbba2SJérôme Glisse return; 285c01cbba2SJérôme Glisse 286*86a2d598SRalph Campbell mmu_notifier_unregister_no_release(&hmm->mmu_notifier, mm); 287*86a2d598SRalph Campbell 288c01cbba2SJérôme Glisse spin_lock(&mm->page_table_lock); 289c01cbba2SJérôme Glisse if (mm->hmm == hmm) 290c01cbba2SJérôme Glisse mm->hmm = NULL; 291c01cbba2SJérôme Glisse spin_unlock(&mm->page_table_lock); 292c01cbba2SJérôme Glisse 293c01cbba2SJérôme Glisse kfree(hmm); 294c0b12405SJérôme Glisse } 295c0b12405SJérôme Glisse EXPORT_SYMBOL(hmm_mirror_unregister); 296da4c3c73SJérôme Glisse 29774eee180SJérôme Glisse struct hmm_vma_walk { 29874eee180SJérôme Glisse struct hmm_range *range; 29974eee180SJérôme Glisse unsigned long last; 30074eee180SJérôme Glisse bool fault; 30174eee180SJérôme Glisse bool block; 30274eee180SJérôme Glisse }; 30374eee180SJérôme Glisse 3042aee09d8SJérôme Glisse static int hmm_vma_do_fault(struct mm_walk *walk, unsigned long addr, 3052aee09d8SJérôme Glisse bool write_fault, uint64_t *pfn) 30674eee180SJérôme Glisse { 30774eee180SJérôme Glisse unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_REMOTE; 30874eee180SJérôme Glisse struct hmm_vma_walk *hmm_vma_walk = walk->private; 309f88a1e90SJérôme Glisse struct hmm_range *range = hmm_vma_walk->range; 31074eee180SJérôme Glisse struct vm_area_struct *vma = walk->vma; 31150a7ca3cSSouptick Joarder vm_fault_t ret; 31274eee180SJérôme Glisse 31374eee180SJérôme Glisse flags |= hmm_vma_walk->block ? 0 : FAULT_FLAG_ALLOW_RETRY; 3142aee09d8SJérôme Glisse flags |= write_fault ? FAULT_FLAG_WRITE : 0; 31550a7ca3cSSouptick Joarder ret = handle_mm_fault(vma, addr, flags); 31650a7ca3cSSouptick Joarder if (ret & VM_FAULT_RETRY) 31774eee180SJérôme Glisse return -EBUSY; 31850a7ca3cSSouptick Joarder if (ret & VM_FAULT_ERROR) { 319f88a1e90SJérôme Glisse *pfn = range->values[HMM_PFN_ERROR]; 32074eee180SJérôme Glisse return -EFAULT; 32174eee180SJérôme Glisse } 32274eee180SJérôme Glisse 32374eee180SJérôme Glisse return -EAGAIN; 32474eee180SJérôme Glisse } 32574eee180SJérôme Glisse 326da4c3c73SJérôme Glisse static int hmm_pfns_bad(unsigned long addr, 327da4c3c73SJérôme Glisse unsigned long end, 328da4c3c73SJérôme Glisse struct mm_walk *walk) 329da4c3c73SJérôme Glisse { 330c719547fSJérôme Glisse struct hmm_vma_walk *hmm_vma_walk = walk->private; 331c719547fSJérôme Glisse struct hmm_range *range = hmm_vma_walk->range; 332ff05c0c6SJérôme Glisse uint64_t *pfns = range->pfns; 333da4c3c73SJérôme Glisse unsigned long i; 334da4c3c73SJérôme Glisse 335da4c3c73SJérôme Glisse i = (addr - range->start) >> PAGE_SHIFT; 336da4c3c73SJérôme Glisse for (; addr < end; addr += PAGE_SIZE, i++) 337f88a1e90SJérôme Glisse pfns[i] = range->values[HMM_PFN_ERROR]; 338da4c3c73SJérôme Glisse 339da4c3c73SJérôme Glisse return 0; 340da4c3c73SJérôme Glisse } 341da4c3c73SJérôme Glisse 3425504ed29SJérôme Glisse /* 3435504ed29SJérôme Glisse * hmm_vma_walk_hole() - handle a range lacking valid pmd or pte(s) 3445504ed29SJérôme Glisse * @start: range virtual start address (inclusive) 3455504ed29SJérôme Glisse * @end: range virtual end address (exclusive) 3462aee09d8SJérôme Glisse * @fault: should we fault or not ? 3472aee09d8SJérôme Glisse * @write_fault: write fault ? 3485504ed29SJérôme Glisse * @walk: mm_walk structure 3495504ed29SJérôme Glisse * Returns: 0 on success, -EAGAIN after page fault, or page fault error 3505504ed29SJérôme Glisse * 3515504ed29SJérôme Glisse * This function will be called whenever pmd_none() or pte_none() returns true, 3525504ed29SJérôme Glisse * or whenever there is no page directory covering the virtual address range. 3535504ed29SJérôme Glisse */ 3542aee09d8SJérôme Glisse static int hmm_vma_walk_hole_(unsigned long addr, unsigned long end, 3552aee09d8SJérôme Glisse bool fault, bool write_fault, 356da4c3c73SJérôme Glisse struct mm_walk *walk) 357da4c3c73SJérôme Glisse { 35874eee180SJérôme Glisse struct hmm_vma_walk *hmm_vma_walk = walk->private; 35974eee180SJérôme Glisse struct hmm_range *range = hmm_vma_walk->range; 360ff05c0c6SJérôme Glisse uint64_t *pfns = range->pfns; 361da4c3c73SJérôme Glisse unsigned long i; 362da4c3c73SJérôme Glisse 36374eee180SJérôme Glisse hmm_vma_walk->last = addr; 364da4c3c73SJérôme Glisse i = (addr - range->start) >> PAGE_SHIFT; 36574eee180SJérôme Glisse for (; addr < end; addr += PAGE_SIZE, i++) { 366f88a1e90SJérôme Glisse pfns[i] = range->values[HMM_PFN_NONE]; 3672aee09d8SJérôme Glisse if (fault || write_fault) { 36874eee180SJérôme Glisse int ret; 369da4c3c73SJérôme Glisse 3702aee09d8SJérôme Glisse ret = hmm_vma_do_fault(walk, addr, write_fault, 3712aee09d8SJérôme Glisse &pfns[i]); 37274eee180SJérôme Glisse if (ret != -EAGAIN) 37374eee180SJérôme Glisse return ret; 37474eee180SJérôme Glisse } 37574eee180SJérôme Glisse } 37674eee180SJérôme Glisse 3772aee09d8SJérôme Glisse return (fault || write_fault) ? -EAGAIN : 0; 3782aee09d8SJérôme Glisse } 3792aee09d8SJérôme Glisse 3802aee09d8SJérôme Glisse static inline void hmm_pte_need_fault(const struct hmm_vma_walk *hmm_vma_walk, 3812aee09d8SJérôme Glisse uint64_t pfns, uint64_t cpu_flags, 3822aee09d8SJérôme Glisse bool *fault, bool *write_fault) 3832aee09d8SJérôme Glisse { 384f88a1e90SJérôme Glisse struct hmm_range *range = hmm_vma_walk->range; 385f88a1e90SJérôme Glisse 3862aee09d8SJérôme Glisse *fault = *write_fault = false; 3872aee09d8SJérôme Glisse if (!hmm_vma_walk->fault) 3882aee09d8SJérôme Glisse return; 3892aee09d8SJérôme Glisse 3902aee09d8SJérôme Glisse /* We aren't ask to do anything ... */ 391f88a1e90SJérôme Glisse if (!(pfns & range->flags[HMM_PFN_VALID])) 3922aee09d8SJérôme Glisse return; 393f88a1e90SJérôme Glisse /* If this is device memory than only fault if explicitly requested */ 394f88a1e90SJérôme Glisse if ((cpu_flags & range->flags[HMM_PFN_DEVICE_PRIVATE])) { 395f88a1e90SJérôme Glisse /* Do we fault on device memory ? */ 396f88a1e90SJérôme Glisse if (pfns & range->flags[HMM_PFN_DEVICE_PRIVATE]) { 397f88a1e90SJérôme Glisse *write_fault = pfns & range->flags[HMM_PFN_WRITE]; 398f88a1e90SJérôme Glisse *fault = true; 399f88a1e90SJérôme Glisse } 4002aee09d8SJérôme Glisse return; 4012aee09d8SJérôme Glisse } 402f88a1e90SJérôme Glisse 403f88a1e90SJérôme Glisse /* If CPU page table is not valid then we need to fault */ 404f88a1e90SJérôme Glisse *fault = !(cpu_flags & range->flags[HMM_PFN_VALID]); 405f88a1e90SJérôme Glisse /* Need to write fault ? */ 406f88a1e90SJérôme Glisse if ((pfns & range->flags[HMM_PFN_WRITE]) && 407f88a1e90SJérôme Glisse !(cpu_flags & range->flags[HMM_PFN_WRITE])) { 408f88a1e90SJérôme Glisse *write_fault = true; 4092aee09d8SJérôme Glisse *fault = true; 4102aee09d8SJérôme Glisse } 4112aee09d8SJérôme Glisse } 4122aee09d8SJérôme Glisse 4132aee09d8SJérôme Glisse static void hmm_range_need_fault(const struct hmm_vma_walk *hmm_vma_walk, 4142aee09d8SJérôme Glisse const uint64_t *pfns, unsigned long npages, 4152aee09d8SJérôme Glisse uint64_t cpu_flags, bool *fault, 4162aee09d8SJérôme Glisse bool *write_fault) 4172aee09d8SJérôme Glisse { 4182aee09d8SJérôme Glisse unsigned long i; 4192aee09d8SJérôme Glisse 4202aee09d8SJérôme Glisse if (!hmm_vma_walk->fault) { 4212aee09d8SJérôme Glisse *fault = *write_fault = false; 4222aee09d8SJérôme Glisse return; 4232aee09d8SJérôme Glisse } 4242aee09d8SJérôme Glisse 4252aee09d8SJérôme Glisse for (i = 0; i < npages; ++i) { 4262aee09d8SJérôme Glisse hmm_pte_need_fault(hmm_vma_walk, pfns[i], cpu_flags, 4272aee09d8SJérôme Glisse fault, write_fault); 4282aee09d8SJérôme Glisse if ((*fault) || (*write_fault)) 4292aee09d8SJérôme Glisse return; 4302aee09d8SJérôme Glisse } 4312aee09d8SJérôme Glisse } 4322aee09d8SJérôme Glisse 4332aee09d8SJérôme Glisse static int hmm_vma_walk_hole(unsigned long addr, unsigned long end, 4342aee09d8SJérôme Glisse struct mm_walk *walk) 4352aee09d8SJérôme Glisse { 4362aee09d8SJérôme Glisse struct hmm_vma_walk *hmm_vma_walk = walk->private; 4372aee09d8SJérôme Glisse struct hmm_range *range = hmm_vma_walk->range; 4382aee09d8SJérôme Glisse bool fault, write_fault; 4392aee09d8SJérôme Glisse unsigned long i, npages; 4402aee09d8SJérôme Glisse uint64_t *pfns; 4412aee09d8SJérôme Glisse 4422aee09d8SJérôme Glisse i = (addr - range->start) >> PAGE_SHIFT; 4432aee09d8SJérôme Glisse npages = (end - addr) >> PAGE_SHIFT; 4442aee09d8SJérôme Glisse pfns = &range->pfns[i]; 4452aee09d8SJérôme Glisse hmm_range_need_fault(hmm_vma_walk, pfns, npages, 4462aee09d8SJérôme Glisse 0, &fault, &write_fault); 4472aee09d8SJérôme Glisse return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk); 4482aee09d8SJérôme Glisse } 4492aee09d8SJérôme Glisse 450f88a1e90SJérôme Glisse static inline uint64_t pmd_to_hmm_pfn_flags(struct hmm_range *range, pmd_t pmd) 4512aee09d8SJérôme Glisse { 4522aee09d8SJérôme Glisse if (pmd_protnone(pmd)) 4532aee09d8SJérôme Glisse return 0; 454f88a1e90SJérôme Glisse return pmd_write(pmd) ? range->flags[HMM_PFN_VALID] | 455f88a1e90SJérôme Glisse range->flags[HMM_PFN_WRITE] : 456f88a1e90SJérôme Glisse range->flags[HMM_PFN_VALID]; 457da4c3c73SJérôme Glisse } 458da4c3c73SJérôme Glisse 45953f5c3f4SJérôme Glisse static int hmm_vma_handle_pmd(struct mm_walk *walk, 46053f5c3f4SJérôme Glisse unsigned long addr, 46153f5c3f4SJérôme Glisse unsigned long end, 46253f5c3f4SJérôme Glisse uint64_t *pfns, 46353f5c3f4SJérôme Glisse pmd_t pmd) 46453f5c3f4SJérôme Glisse { 46553f5c3f4SJérôme Glisse struct hmm_vma_walk *hmm_vma_walk = walk->private; 466f88a1e90SJérôme Glisse struct hmm_range *range = hmm_vma_walk->range; 4672aee09d8SJérôme Glisse unsigned long pfn, npages, i; 4682aee09d8SJérôme Glisse bool fault, write_fault; 469f88a1e90SJérôme Glisse uint64_t cpu_flags; 47053f5c3f4SJérôme Glisse 4712aee09d8SJérôme Glisse npages = (end - addr) >> PAGE_SHIFT; 472f88a1e90SJérôme Glisse cpu_flags = pmd_to_hmm_pfn_flags(range, pmd); 4732aee09d8SJérôme Glisse hmm_range_need_fault(hmm_vma_walk, pfns, npages, cpu_flags, 4742aee09d8SJérôme Glisse &fault, &write_fault); 47553f5c3f4SJérôme Glisse 4762aee09d8SJérôme Glisse if (pmd_protnone(pmd) || fault || write_fault) 4772aee09d8SJérôme Glisse return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk); 47853f5c3f4SJérôme Glisse 47953f5c3f4SJérôme Glisse pfn = pmd_pfn(pmd) + pte_index(addr); 48053f5c3f4SJérôme Glisse for (i = 0; addr < end; addr += PAGE_SIZE, i++, pfn++) 481f88a1e90SJérôme Glisse pfns[i] = hmm_pfn_from_pfn(range, pfn) | cpu_flags; 48253f5c3f4SJérôme Glisse hmm_vma_walk->last = end; 48353f5c3f4SJérôme Glisse return 0; 48453f5c3f4SJérôme Glisse } 48553f5c3f4SJérôme Glisse 486f88a1e90SJérôme Glisse static inline uint64_t pte_to_hmm_pfn_flags(struct hmm_range *range, pte_t pte) 4872aee09d8SJérôme Glisse { 4882aee09d8SJérôme Glisse if (pte_none(pte) || !pte_present(pte)) 4892aee09d8SJérôme Glisse return 0; 490f88a1e90SJérôme Glisse return pte_write(pte) ? range->flags[HMM_PFN_VALID] | 491f88a1e90SJérôme Glisse range->flags[HMM_PFN_WRITE] : 492f88a1e90SJérôme Glisse range->flags[HMM_PFN_VALID]; 4932aee09d8SJérôme Glisse } 4942aee09d8SJérôme Glisse 49553f5c3f4SJérôme Glisse static int hmm_vma_handle_pte(struct mm_walk *walk, unsigned long addr, 49653f5c3f4SJérôme Glisse unsigned long end, pmd_t *pmdp, pte_t *ptep, 49753f5c3f4SJérôme Glisse uint64_t *pfn) 49853f5c3f4SJérôme Glisse { 49953f5c3f4SJérôme Glisse struct hmm_vma_walk *hmm_vma_walk = walk->private; 500f88a1e90SJérôme Glisse struct hmm_range *range = hmm_vma_walk->range; 50153f5c3f4SJérôme Glisse struct vm_area_struct *vma = walk->vma; 5022aee09d8SJérôme Glisse bool fault, write_fault; 5032aee09d8SJérôme Glisse uint64_t cpu_flags; 50453f5c3f4SJérôme Glisse pte_t pte = *ptep; 505f88a1e90SJérôme Glisse uint64_t orig_pfn = *pfn; 50653f5c3f4SJérôme Glisse 507f88a1e90SJérôme Glisse *pfn = range->values[HMM_PFN_NONE]; 508f88a1e90SJérôme Glisse cpu_flags = pte_to_hmm_pfn_flags(range, pte); 509f88a1e90SJérôme Glisse hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags, 5102aee09d8SJérôme Glisse &fault, &write_fault); 51153f5c3f4SJérôme Glisse 51253f5c3f4SJérôme Glisse if (pte_none(pte)) { 5132aee09d8SJérôme Glisse if (fault || write_fault) 51453f5c3f4SJérôme Glisse goto fault; 51553f5c3f4SJérôme Glisse return 0; 51653f5c3f4SJérôme Glisse } 51753f5c3f4SJérôme Glisse 51853f5c3f4SJérôme Glisse if (!pte_present(pte)) { 51953f5c3f4SJérôme Glisse swp_entry_t entry = pte_to_swp_entry(pte); 52053f5c3f4SJérôme Glisse 52153f5c3f4SJérôme Glisse if (!non_swap_entry(entry)) { 5222aee09d8SJérôme Glisse if (fault || write_fault) 52353f5c3f4SJérôme Glisse goto fault; 52453f5c3f4SJérôme Glisse return 0; 52553f5c3f4SJérôme Glisse } 52653f5c3f4SJérôme Glisse 52753f5c3f4SJérôme Glisse /* 52853f5c3f4SJérôme Glisse * This is a special swap entry, ignore migration, use 52953f5c3f4SJérôme Glisse * device and report anything else as error. 53053f5c3f4SJérôme Glisse */ 53153f5c3f4SJérôme Glisse if (is_device_private_entry(entry)) { 532f88a1e90SJérôme Glisse cpu_flags = range->flags[HMM_PFN_VALID] | 533f88a1e90SJérôme Glisse range->flags[HMM_PFN_DEVICE_PRIVATE]; 5342aee09d8SJérôme Glisse cpu_flags |= is_write_device_private_entry(entry) ? 535f88a1e90SJérôme Glisse range->flags[HMM_PFN_WRITE] : 0; 536f88a1e90SJérôme Glisse hmm_pte_need_fault(hmm_vma_walk, orig_pfn, cpu_flags, 537f88a1e90SJérôme Glisse &fault, &write_fault); 538f88a1e90SJérôme Glisse if (fault || write_fault) 539f88a1e90SJérôme Glisse goto fault; 540f88a1e90SJérôme Glisse *pfn = hmm_pfn_from_pfn(range, swp_offset(entry)); 541f88a1e90SJérôme Glisse *pfn |= cpu_flags; 54253f5c3f4SJérôme Glisse return 0; 54353f5c3f4SJérôme Glisse } 54453f5c3f4SJérôme Glisse 54553f5c3f4SJérôme Glisse if (is_migration_entry(entry)) { 5462aee09d8SJérôme Glisse if (fault || write_fault) { 54753f5c3f4SJérôme Glisse pte_unmap(ptep); 54853f5c3f4SJérôme Glisse hmm_vma_walk->last = addr; 54953f5c3f4SJérôme Glisse migration_entry_wait(vma->vm_mm, 55053f5c3f4SJérôme Glisse pmdp, addr); 55153f5c3f4SJérôme Glisse return -EAGAIN; 55253f5c3f4SJérôme Glisse } 55353f5c3f4SJérôme Glisse return 0; 55453f5c3f4SJérôme Glisse } 55553f5c3f4SJérôme Glisse 55653f5c3f4SJérôme Glisse /* Report error for everything else */ 557f88a1e90SJérôme Glisse *pfn = range->values[HMM_PFN_ERROR]; 55853f5c3f4SJérôme Glisse return -EFAULT; 55953f5c3f4SJérôme Glisse } 56053f5c3f4SJérôme Glisse 5612aee09d8SJérôme Glisse if (fault || write_fault) 56253f5c3f4SJérôme Glisse goto fault; 56353f5c3f4SJérôme Glisse 564f88a1e90SJérôme Glisse *pfn = hmm_pfn_from_pfn(range, pte_pfn(pte)) | cpu_flags; 56553f5c3f4SJérôme Glisse return 0; 56653f5c3f4SJérôme Glisse 56753f5c3f4SJérôme Glisse fault: 56853f5c3f4SJérôme Glisse pte_unmap(ptep); 56953f5c3f4SJérôme Glisse /* Fault any virtual address we were asked to fault */ 5702aee09d8SJérôme Glisse return hmm_vma_walk_hole_(addr, end, fault, write_fault, walk); 57153f5c3f4SJérôme Glisse } 57253f5c3f4SJérôme Glisse 573da4c3c73SJérôme Glisse static int hmm_vma_walk_pmd(pmd_t *pmdp, 574da4c3c73SJérôme Glisse unsigned long start, 575da4c3c73SJérôme Glisse unsigned long end, 576da4c3c73SJérôme Glisse struct mm_walk *walk) 577da4c3c73SJérôme Glisse { 57874eee180SJérôme Glisse struct hmm_vma_walk *hmm_vma_walk = walk->private; 57974eee180SJérôme Glisse struct hmm_range *range = hmm_vma_walk->range; 580ff05c0c6SJérôme Glisse uint64_t *pfns = range->pfns; 581da4c3c73SJérôme Glisse unsigned long addr = start, i; 582da4c3c73SJérôme Glisse pte_t *ptep; 583da4c3c73SJérôme Glisse 584da4c3c73SJérôme Glisse i = (addr - range->start) >> PAGE_SHIFT; 585da4c3c73SJérôme Glisse 586da4c3c73SJérôme Glisse again: 587da4c3c73SJérôme Glisse if (pmd_none(*pmdp)) 588da4c3c73SJérôme Glisse return hmm_vma_walk_hole(start, end, walk); 589da4c3c73SJérôme Glisse 59053f5c3f4SJérôme Glisse if (pmd_huge(*pmdp) && (range->vma->vm_flags & VM_HUGETLB)) 591da4c3c73SJérôme Glisse return hmm_pfns_bad(start, end, walk); 592da4c3c73SJérôme Glisse 593da4c3c73SJérôme Glisse if (pmd_devmap(*pmdp) || pmd_trans_huge(*pmdp)) { 594da4c3c73SJérôme Glisse pmd_t pmd; 595da4c3c73SJérôme Glisse 596da4c3c73SJérôme Glisse /* 597da4c3c73SJérôme Glisse * No need to take pmd_lock here, even if some other threads 598da4c3c73SJérôme Glisse * is splitting the huge pmd we will get that event through 599da4c3c73SJérôme Glisse * mmu_notifier callback. 600da4c3c73SJérôme Glisse * 601da4c3c73SJérôme Glisse * So just read pmd value and check again its a transparent 602da4c3c73SJérôme Glisse * huge or device mapping one and compute corresponding pfn 603da4c3c73SJérôme Glisse * values. 604da4c3c73SJérôme Glisse */ 605da4c3c73SJérôme Glisse pmd = pmd_read_atomic(pmdp); 606da4c3c73SJérôme Glisse barrier(); 607da4c3c73SJérôme Glisse if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd)) 608da4c3c73SJérôme Glisse goto again; 609da4c3c73SJérôme Glisse 61053f5c3f4SJérôme Glisse return hmm_vma_handle_pmd(walk, addr, end, &pfns[i], pmd); 611da4c3c73SJérôme Glisse } 612da4c3c73SJérôme Glisse 613da4c3c73SJérôme Glisse if (pmd_bad(*pmdp)) 614da4c3c73SJérôme Glisse return hmm_pfns_bad(start, end, walk); 615da4c3c73SJérôme Glisse 616da4c3c73SJérôme Glisse ptep = pte_offset_map(pmdp, addr); 617da4c3c73SJérôme Glisse for (; addr < end; addr += PAGE_SIZE, ptep++, i++) { 61853f5c3f4SJérôme Glisse int r; 619da4c3c73SJérôme Glisse 62053f5c3f4SJérôme Glisse r = hmm_vma_handle_pte(walk, addr, end, pmdp, ptep, &pfns[i]); 62153f5c3f4SJérôme Glisse if (r) { 62253f5c3f4SJérôme Glisse /* hmm_vma_handle_pte() did unmap pte directory */ 62374eee180SJérôme Glisse hmm_vma_walk->last = addr; 62453f5c3f4SJérôme Glisse return r; 62574eee180SJérôme Glisse } 626da4c3c73SJérôme Glisse } 627da4c3c73SJérôme Glisse pte_unmap(ptep - 1); 628da4c3c73SJérôme Glisse 62953f5c3f4SJérôme Glisse hmm_vma_walk->last = addr; 630da4c3c73SJérôme Glisse return 0; 631da4c3c73SJérôme Glisse } 632da4c3c73SJérôme Glisse 633f88a1e90SJérôme Glisse static void hmm_pfns_clear(struct hmm_range *range, 634f88a1e90SJérôme Glisse uint64_t *pfns, 63533cd47dcSJérôme Glisse unsigned long addr, 63633cd47dcSJérôme Glisse unsigned long end) 63733cd47dcSJérôme Glisse { 63833cd47dcSJérôme Glisse for (; addr < end; addr += PAGE_SIZE, pfns++) 639f88a1e90SJérôme Glisse *pfns = range->values[HMM_PFN_NONE]; 64033cd47dcSJérôme Glisse } 64133cd47dcSJérôme Glisse 642855ce7d2SJérôme Glisse static void hmm_pfns_special(struct hmm_range *range) 643855ce7d2SJérôme Glisse { 644855ce7d2SJérôme Glisse unsigned long addr = range->start, i = 0; 645855ce7d2SJérôme Glisse 646855ce7d2SJérôme Glisse for (; addr < range->end; addr += PAGE_SIZE, i++) 647f88a1e90SJérôme Glisse range->pfns[i] = range->values[HMM_PFN_SPECIAL]; 648855ce7d2SJérôme Glisse } 649855ce7d2SJérôme Glisse 650da4c3c73SJérôme Glisse /* 651da4c3c73SJérôme Glisse * hmm_vma_get_pfns() - snapshot CPU page table for a range of virtual addresses 65208232a45SJérôme Glisse * @range: range being snapshotted 65386586a41SJérôme Glisse * Returns: -EINVAL if invalid argument, -ENOMEM out of memory, -EPERM invalid 65486586a41SJérôme Glisse * vma permission, 0 success 655da4c3c73SJérôme Glisse * 656da4c3c73SJérôme Glisse * This snapshots the CPU page table for a range of virtual addresses. Snapshot 657da4c3c73SJérôme Glisse * validity is tracked by range struct. See hmm_vma_range_done() for further 658da4c3c73SJérôme Glisse * information. 659da4c3c73SJérôme Glisse * 660da4c3c73SJérôme Glisse * The range struct is initialized here. It tracks the CPU page table, but only 661da4c3c73SJérôme Glisse * if the function returns success (0), in which case the caller must then call 662da4c3c73SJérôme Glisse * hmm_vma_range_done() to stop CPU page table update tracking on this range. 663da4c3c73SJérôme Glisse * 664da4c3c73SJérôme Glisse * NOT CALLING hmm_vma_range_done() IF FUNCTION RETURNS 0 WILL LEAD TO SERIOUS 665da4c3c73SJérôme Glisse * MEMORY CORRUPTION ! YOU HAVE BEEN WARNED ! 666da4c3c73SJérôme Glisse */ 66708232a45SJérôme Glisse int hmm_vma_get_pfns(struct hmm_range *range) 668da4c3c73SJérôme Glisse { 66908232a45SJérôme Glisse struct vm_area_struct *vma = range->vma; 67074eee180SJérôme Glisse struct hmm_vma_walk hmm_vma_walk; 671da4c3c73SJérôme Glisse struct mm_walk mm_walk; 672da4c3c73SJérôme Glisse struct hmm *hmm; 673da4c3c73SJérôme Glisse 674da4c3c73SJérôme Glisse /* Sanity check, this really should not happen ! */ 67508232a45SJérôme Glisse if (range->start < vma->vm_start || range->start >= vma->vm_end) 676da4c3c73SJérôme Glisse return -EINVAL; 67708232a45SJérôme Glisse if (range->end < vma->vm_start || range->end > vma->vm_end) 678da4c3c73SJérôme Glisse return -EINVAL; 679da4c3c73SJérôme Glisse 680da4c3c73SJérôme Glisse hmm = hmm_register(vma->vm_mm); 681da4c3c73SJérôme Glisse if (!hmm) 682da4c3c73SJérôme Glisse return -ENOMEM; 683da4c3c73SJérôme Glisse /* Caller must have registered a mirror, via hmm_mirror_register() ! */ 684da4c3c73SJérôme Glisse if (!hmm->mmu_notifier.ops) 685da4c3c73SJérôme Glisse return -EINVAL; 686da4c3c73SJérôme Glisse 687855ce7d2SJérôme Glisse /* FIXME support hugetlb fs */ 688e1fb4a08SDave Jiang if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL) || 689e1fb4a08SDave Jiang vma_is_dax(vma)) { 690855ce7d2SJérôme Glisse hmm_pfns_special(range); 691855ce7d2SJérôme Glisse return -EINVAL; 692855ce7d2SJérôme Glisse } 693855ce7d2SJérôme Glisse 69486586a41SJérôme Glisse if (!(vma->vm_flags & VM_READ)) { 69586586a41SJérôme Glisse /* 69686586a41SJérôme Glisse * If vma do not allow read access, then assume that it does 69786586a41SJérôme Glisse * not allow write access, either. Architecture that allow 69886586a41SJérôme Glisse * write without read access are not supported by HMM, because 69986586a41SJérôme Glisse * operations such has atomic access would not work. 70086586a41SJérôme Glisse */ 701f88a1e90SJérôme Glisse hmm_pfns_clear(range, range->pfns, range->start, range->end); 70286586a41SJérôme Glisse return -EPERM; 70386586a41SJérôme Glisse } 70486586a41SJérôme Glisse 705da4c3c73SJérôme Glisse /* Initialize range to track CPU page table update */ 706da4c3c73SJérôme Glisse spin_lock(&hmm->lock); 707da4c3c73SJérôme Glisse range->valid = true; 708da4c3c73SJérôme Glisse list_add_rcu(&range->list, &hmm->ranges); 709da4c3c73SJérôme Glisse spin_unlock(&hmm->lock); 710da4c3c73SJérôme Glisse 71174eee180SJérôme Glisse hmm_vma_walk.fault = false; 71274eee180SJérôme Glisse hmm_vma_walk.range = range; 71374eee180SJérôme Glisse mm_walk.private = &hmm_vma_walk; 71474eee180SJérôme Glisse 715da4c3c73SJérôme Glisse mm_walk.vma = vma; 716da4c3c73SJérôme Glisse mm_walk.mm = vma->vm_mm; 717da4c3c73SJérôme Glisse mm_walk.pte_entry = NULL; 718da4c3c73SJérôme Glisse mm_walk.test_walk = NULL; 719da4c3c73SJérôme Glisse mm_walk.hugetlb_entry = NULL; 720da4c3c73SJérôme Glisse mm_walk.pmd_entry = hmm_vma_walk_pmd; 721da4c3c73SJérôme Glisse mm_walk.pte_hole = hmm_vma_walk_hole; 722da4c3c73SJérôme Glisse 72308232a45SJérôme Glisse walk_page_range(range->start, range->end, &mm_walk); 724da4c3c73SJérôme Glisse return 0; 725da4c3c73SJérôme Glisse } 726da4c3c73SJérôme Glisse EXPORT_SYMBOL(hmm_vma_get_pfns); 727da4c3c73SJérôme Glisse 728da4c3c73SJérôme Glisse /* 729da4c3c73SJérôme Glisse * hmm_vma_range_done() - stop tracking change to CPU page table over a range 730da4c3c73SJérôme Glisse * @range: range being tracked 731da4c3c73SJérôme Glisse * Returns: false if range data has been invalidated, true otherwise 732da4c3c73SJérôme Glisse * 733da4c3c73SJérôme Glisse * Range struct is used to track updates to the CPU page table after a call to 734da4c3c73SJérôme Glisse * either hmm_vma_get_pfns() or hmm_vma_fault(). Once the device driver is done 735da4c3c73SJérôme Glisse * using the data, or wants to lock updates to the data it got from those 736da4c3c73SJérôme Glisse * functions, it must call the hmm_vma_range_done() function, which will then 737da4c3c73SJérôme Glisse * stop tracking CPU page table updates. 738da4c3c73SJérôme Glisse * 739da4c3c73SJérôme Glisse * Note that device driver must still implement general CPU page table update 740da4c3c73SJérôme Glisse * tracking either by using hmm_mirror (see hmm_mirror_register()) or by using 741da4c3c73SJérôme Glisse * the mmu_notifier API directly. 742da4c3c73SJérôme Glisse * 743da4c3c73SJérôme Glisse * CPU page table update tracking done through hmm_range is only temporary and 744da4c3c73SJérôme Glisse * to be used while trying to duplicate CPU page table contents for a range of 745da4c3c73SJérôme Glisse * virtual addresses. 746da4c3c73SJérôme Glisse * 747da4c3c73SJérôme Glisse * There are two ways to use this : 748da4c3c73SJérôme Glisse * again: 74908232a45SJérôme Glisse * hmm_vma_get_pfns(range); or hmm_vma_fault(...); 750da4c3c73SJérôme Glisse * trans = device_build_page_table_update_transaction(pfns); 751da4c3c73SJérôme Glisse * device_page_table_lock(); 75208232a45SJérôme Glisse * if (!hmm_vma_range_done(range)) { 753da4c3c73SJérôme Glisse * device_page_table_unlock(); 754da4c3c73SJérôme Glisse * goto again; 755da4c3c73SJérôme Glisse * } 756da4c3c73SJérôme Glisse * device_commit_transaction(trans); 757da4c3c73SJérôme Glisse * device_page_table_unlock(); 758da4c3c73SJérôme Glisse * 759da4c3c73SJérôme Glisse * Or: 76008232a45SJérôme Glisse * hmm_vma_get_pfns(range); or hmm_vma_fault(...); 761da4c3c73SJérôme Glisse * device_page_table_lock(); 76208232a45SJérôme Glisse * hmm_vma_range_done(range); 76308232a45SJérôme Glisse * device_update_page_table(range->pfns); 764da4c3c73SJérôme Glisse * device_page_table_unlock(); 765da4c3c73SJérôme Glisse */ 76608232a45SJérôme Glisse bool hmm_vma_range_done(struct hmm_range *range) 767da4c3c73SJérôme Glisse { 768da4c3c73SJérôme Glisse unsigned long npages = (range->end - range->start) >> PAGE_SHIFT; 769da4c3c73SJérôme Glisse struct hmm *hmm; 770da4c3c73SJérôme Glisse 771da4c3c73SJérôme Glisse if (range->end <= range->start) { 772da4c3c73SJérôme Glisse BUG(); 773da4c3c73SJérôme Glisse return false; 774da4c3c73SJérôme Glisse } 775da4c3c73SJérôme Glisse 77608232a45SJérôme Glisse hmm = hmm_register(range->vma->vm_mm); 777da4c3c73SJérôme Glisse if (!hmm) { 778da4c3c73SJérôme Glisse memset(range->pfns, 0, sizeof(*range->pfns) * npages); 779da4c3c73SJérôme Glisse return false; 780da4c3c73SJérôme Glisse } 781da4c3c73SJérôme Glisse 782da4c3c73SJérôme Glisse spin_lock(&hmm->lock); 783da4c3c73SJérôme Glisse list_del_rcu(&range->list); 784da4c3c73SJérôme Glisse spin_unlock(&hmm->lock); 785da4c3c73SJérôme Glisse 786da4c3c73SJérôme Glisse return range->valid; 787da4c3c73SJérôme Glisse } 788da4c3c73SJérôme Glisse EXPORT_SYMBOL(hmm_vma_range_done); 78974eee180SJérôme Glisse 79074eee180SJérôme Glisse /* 79174eee180SJérôme Glisse * hmm_vma_fault() - try to fault some address in a virtual address range 79208232a45SJérôme Glisse * @range: range being faulted 79374eee180SJérôme Glisse * @block: allow blocking on fault (if true it sleeps and do not drop mmap_sem) 79474eee180SJérôme Glisse * Returns: 0 success, error otherwise (-EAGAIN means mmap_sem have been drop) 79574eee180SJérôme Glisse * 79674eee180SJérôme Glisse * This is similar to a regular CPU page fault except that it will not trigger 79774eee180SJérôme Glisse * any memory migration if the memory being faulted is not accessible by CPUs. 79874eee180SJérôme Glisse * 799ff05c0c6SJérôme Glisse * On error, for one virtual address in the range, the function will mark the 800ff05c0c6SJérôme Glisse * corresponding HMM pfn entry with an error flag. 80174eee180SJérôme Glisse * 80274eee180SJérôme Glisse * Expected use pattern: 80374eee180SJérôme Glisse * retry: 80474eee180SJérôme Glisse * down_read(&mm->mmap_sem); 80574eee180SJérôme Glisse * // Find vma and address device wants to fault, initialize hmm_pfn_t 80674eee180SJérôme Glisse * // array accordingly 80708232a45SJérôme Glisse * ret = hmm_vma_fault(range, write, block); 80874eee180SJérôme Glisse * switch (ret) { 80974eee180SJérôme Glisse * case -EAGAIN: 81008232a45SJérôme Glisse * hmm_vma_range_done(range); 81174eee180SJérôme Glisse * // You might want to rate limit or yield to play nicely, you may 81274eee180SJérôme Glisse * // also commit any valid pfn in the array assuming that you are 81374eee180SJérôme Glisse * // getting true from hmm_vma_range_monitor_end() 81474eee180SJérôme Glisse * goto retry; 81574eee180SJérôme Glisse * case 0: 81674eee180SJérôme Glisse * break; 81786586a41SJérôme Glisse * case -ENOMEM: 81886586a41SJérôme Glisse * case -EINVAL: 81986586a41SJérôme Glisse * case -EPERM: 82074eee180SJérôme Glisse * default: 82174eee180SJérôme Glisse * // Handle error ! 82274eee180SJérôme Glisse * up_read(&mm->mmap_sem) 82374eee180SJérôme Glisse * return; 82474eee180SJérôme Glisse * } 82574eee180SJérôme Glisse * // Take device driver lock that serialize device page table update 82674eee180SJérôme Glisse * driver_lock_device_page_table_update(); 82708232a45SJérôme Glisse * hmm_vma_range_done(range); 82874eee180SJérôme Glisse * // Commit pfns we got from hmm_vma_fault() 82974eee180SJérôme Glisse * driver_unlock_device_page_table_update(); 83074eee180SJérôme Glisse * up_read(&mm->mmap_sem) 83174eee180SJérôme Glisse * 83274eee180SJérôme Glisse * YOU MUST CALL hmm_vma_range_done() AFTER THIS FUNCTION RETURN SUCCESS (0) 83374eee180SJérôme Glisse * BEFORE FREEING THE range struct OR YOU WILL HAVE SERIOUS MEMORY CORRUPTION ! 83474eee180SJérôme Glisse * 83574eee180SJérôme Glisse * YOU HAVE BEEN WARNED ! 83674eee180SJérôme Glisse */ 8372aee09d8SJérôme Glisse int hmm_vma_fault(struct hmm_range *range, bool block) 83874eee180SJérôme Glisse { 83908232a45SJérôme Glisse struct vm_area_struct *vma = range->vma; 84008232a45SJérôme Glisse unsigned long start = range->start; 84174eee180SJérôme Glisse struct hmm_vma_walk hmm_vma_walk; 84274eee180SJérôme Glisse struct mm_walk mm_walk; 84374eee180SJérôme Glisse struct hmm *hmm; 84474eee180SJérôme Glisse int ret; 84574eee180SJérôme Glisse 84674eee180SJérôme Glisse /* Sanity check, this really should not happen ! */ 84708232a45SJérôme Glisse if (range->start < vma->vm_start || range->start >= vma->vm_end) 84874eee180SJérôme Glisse return -EINVAL; 84908232a45SJérôme Glisse if (range->end < vma->vm_start || range->end > vma->vm_end) 85074eee180SJérôme Glisse return -EINVAL; 85174eee180SJérôme Glisse 85274eee180SJérôme Glisse hmm = hmm_register(vma->vm_mm); 85374eee180SJérôme Glisse if (!hmm) { 854f88a1e90SJérôme Glisse hmm_pfns_clear(range, range->pfns, range->start, range->end); 85574eee180SJérôme Glisse return -ENOMEM; 85674eee180SJérôme Glisse } 85774eee180SJérôme Glisse /* Caller must have registered a mirror using hmm_mirror_register() */ 85874eee180SJérôme Glisse if (!hmm->mmu_notifier.ops) 85974eee180SJérôme Glisse return -EINVAL; 86074eee180SJérôme Glisse 861855ce7d2SJérôme Glisse /* FIXME support hugetlb fs */ 862e1fb4a08SDave Jiang if (is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_SPECIAL) || 863e1fb4a08SDave Jiang vma_is_dax(vma)) { 864855ce7d2SJérôme Glisse hmm_pfns_special(range); 865855ce7d2SJérôme Glisse return -EINVAL; 866855ce7d2SJérôme Glisse } 867855ce7d2SJérôme Glisse 86886586a41SJérôme Glisse if (!(vma->vm_flags & VM_READ)) { 86986586a41SJérôme Glisse /* 87086586a41SJérôme Glisse * If vma do not allow read access, then assume that it does 87186586a41SJérôme Glisse * not allow write access, either. Architecture that allow 87286586a41SJérôme Glisse * write without read access are not supported by HMM, because 87386586a41SJérôme Glisse * operations such has atomic access would not work. 87486586a41SJérôme Glisse */ 875f88a1e90SJérôme Glisse hmm_pfns_clear(range, range->pfns, range->start, range->end); 87686586a41SJérôme Glisse return -EPERM; 87786586a41SJérôme Glisse } 87874eee180SJérôme Glisse 87986586a41SJérôme Glisse /* Initialize range to track CPU page table update */ 88086586a41SJérôme Glisse spin_lock(&hmm->lock); 88186586a41SJérôme Glisse range->valid = true; 88286586a41SJérôme Glisse list_add_rcu(&range->list, &hmm->ranges); 88386586a41SJérôme Glisse spin_unlock(&hmm->lock); 88486586a41SJérôme Glisse 88574eee180SJérôme Glisse hmm_vma_walk.fault = true; 88674eee180SJérôme Glisse hmm_vma_walk.block = block; 88774eee180SJérôme Glisse hmm_vma_walk.range = range; 88874eee180SJérôme Glisse mm_walk.private = &hmm_vma_walk; 88974eee180SJérôme Glisse hmm_vma_walk.last = range->start; 89074eee180SJérôme Glisse 89174eee180SJérôme Glisse mm_walk.vma = vma; 89274eee180SJérôme Glisse mm_walk.mm = vma->vm_mm; 89374eee180SJérôme Glisse mm_walk.pte_entry = NULL; 89474eee180SJérôme Glisse mm_walk.test_walk = NULL; 89574eee180SJérôme Glisse mm_walk.hugetlb_entry = NULL; 89674eee180SJérôme Glisse mm_walk.pmd_entry = hmm_vma_walk_pmd; 89774eee180SJérôme Glisse mm_walk.pte_hole = hmm_vma_walk_hole; 89874eee180SJérôme Glisse 89974eee180SJérôme Glisse do { 90008232a45SJérôme Glisse ret = walk_page_range(start, range->end, &mm_walk); 90174eee180SJérôme Glisse start = hmm_vma_walk.last; 90274eee180SJérôme Glisse } while (ret == -EAGAIN); 90374eee180SJérôme Glisse 90474eee180SJérôme Glisse if (ret) { 90574eee180SJérôme Glisse unsigned long i; 90674eee180SJérôme Glisse 90774eee180SJérôme Glisse i = (hmm_vma_walk.last - range->start) >> PAGE_SHIFT; 908f88a1e90SJérôme Glisse hmm_pfns_clear(range, &range->pfns[i], hmm_vma_walk.last, 909f88a1e90SJérôme Glisse range->end); 91008232a45SJérôme Glisse hmm_vma_range_done(range); 91174eee180SJérôme Glisse } 91274eee180SJérôme Glisse return ret; 91374eee180SJérôme Glisse } 91474eee180SJérôme Glisse EXPORT_SYMBOL(hmm_vma_fault); 915c0b12405SJérôme Glisse #endif /* IS_ENABLED(CONFIG_HMM_MIRROR) */ 9164ef589dcSJérôme Glisse 9174ef589dcSJérôme Glisse 918df6ad698SJérôme Glisse #if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC) 9194ef589dcSJérôme Glisse struct page *hmm_vma_alloc_locked_page(struct vm_area_struct *vma, 9204ef589dcSJérôme Glisse unsigned long addr) 9214ef589dcSJérôme Glisse { 9224ef589dcSJérôme Glisse struct page *page; 9234ef589dcSJérôme Glisse 9244ef589dcSJérôme Glisse page = alloc_page_vma(GFP_HIGHUSER, vma, addr); 9254ef589dcSJérôme Glisse if (!page) 9264ef589dcSJérôme Glisse return NULL; 9274ef589dcSJérôme Glisse lock_page(page); 9284ef589dcSJérôme Glisse return page; 9294ef589dcSJérôme Glisse } 9304ef589dcSJérôme Glisse EXPORT_SYMBOL(hmm_vma_alloc_locked_page); 9314ef589dcSJérôme Glisse 9324ef589dcSJérôme Glisse 9334ef589dcSJérôme Glisse static void hmm_devmem_ref_release(struct percpu_ref *ref) 9344ef589dcSJérôme Glisse { 9354ef589dcSJérôme Glisse struct hmm_devmem *devmem; 9364ef589dcSJérôme Glisse 9374ef589dcSJérôme Glisse devmem = container_of(ref, struct hmm_devmem, ref); 9384ef589dcSJérôme Glisse complete(&devmem->completion); 9394ef589dcSJérôme Glisse } 9404ef589dcSJérôme Glisse 9414ef589dcSJérôme Glisse static void hmm_devmem_ref_exit(void *data) 9424ef589dcSJérôme Glisse { 9434ef589dcSJérôme Glisse struct percpu_ref *ref = data; 9444ef589dcSJérôme Glisse struct hmm_devmem *devmem; 9454ef589dcSJérôme Glisse 9464ef589dcSJérôme Glisse devmem = container_of(ref, struct hmm_devmem, ref); 9474ef589dcSJérôme Glisse percpu_ref_exit(ref); 9484ef589dcSJérôme Glisse devm_remove_action(devmem->device, &hmm_devmem_ref_exit, data); 9494ef589dcSJérôme Glisse } 9504ef589dcSJérôme Glisse 9514ef589dcSJérôme Glisse static void hmm_devmem_ref_kill(void *data) 9524ef589dcSJérôme Glisse { 9534ef589dcSJérôme Glisse struct percpu_ref *ref = data; 9544ef589dcSJérôme Glisse struct hmm_devmem *devmem; 9554ef589dcSJérôme Glisse 9564ef589dcSJérôme Glisse devmem = container_of(ref, struct hmm_devmem, ref); 9574ef589dcSJérôme Glisse percpu_ref_kill(ref); 9584ef589dcSJérôme Glisse wait_for_completion(&devmem->completion); 9594ef589dcSJérôme Glisse devm_remove_action(devmem->device, &hmm_devmem_ref_kill, data); 9604ef589dcSJérôme Glisse } 9614ef589dcSJérôme Glisse 9624ef589dcSJérôme Glisse static int hmm_devmem_fault(struct vm_area_struct *vma, 9634ef589dcSJérôme Glisse unsigned long addr, 9644ef589dcSJérôme Glisse const struct page *page, 9654ef589dcSJérôme Glisse unsigned int flags, 9664ef589dcSJérôme Glisse pmd_t *pmdp) 9674ef589dcSJérôme Glisse { 9684ef589dcSJérôme Glisse struct hmm_devmem *devmem = page->pgmap->data; 9694ef589dcSJérôme Glisse 9704ef589dcSJérôme Glisse return devmem->ops->fault(devmem, vma, addr, page, flags, pmdp); 9714ef589dcSJérôme Glisse } 9724ef589dcSJérôme Glisse 9734ef589dcSJérôme Glisse static void hmm_devmem_free(struct page *page, void *data) 9744ef589dcSJérôme Glisse { 9754ef589dcSJérôme Glisse struct hmm_devmem *devmem = data; 9764ef589dcSJérôme Glisse 9772fa147bdSDan Williams page->mapping = NULL; 9782fa147bdSDan Williams 9794ef589dcSJérôme Glisse devmem->ops->free(devmem, page); 9804ef589dcSJérôme Glisse } 9814ef589dcSJérôme Glisse 9824ef589dcSJérôme Glisse static DEFINE_MUTEX(hmm_devmem_lock); 9834ef589dcSJérôme Glisse static RADIX_TREE(hmm_devmem_radix, GFP_KERNEL); 9844ef589dcSJérôme Glisse 9854ef589dcSJérôme Glisse static void hmm_devmem_radix_release(struct resource *resource) 9864ef589dcSJérôme Glisse { 9871e926419SColin Ian King resource_size_t key; 9884ef589dcSJérôme Glisse 9894ef589dcSJérôme Glisse mutex_lock(&hmm_devmem_lock); 9904ef589dcSJérôme Glisse for (key = resource->start; 9914ef589dcSJérôme Glisse key <= resource->end; 9924ef589dcSJérôme Glisse key += PA_SECTION_SIZE) 9934ef589dcSJérôme Glisse radix_tree_delete(&hmm_devmem_radix, key >> PA_SECTION_SHIFT); 9944ef589dcSJérôme Glisse mutex_unlock(&hmm_devmem_lock); 9954ef589dcSJérôme Glisse } 9964ef589dcSJérôme Glisse 9974ef589dcSJérôme Glisse static void hmm_devmem_release(struct device *dev, void *data) 9984ef589dcSJérôme Glisse { 9994ef589dcSJérôme Glisse struct hmm_devmem *devmem = data; 10004ef589dcSJérôme Glisse struct resource *resource = devmem->resource; 10014ef589dcSJérôme Glisse unsigned long start_pfn, npages; 10024ef589dcSJérôme Glisse struct zone *zone; 10034ef589dcSJérôme Glisse struct page *page; 10044ef589dcSJérôme Glisse 10054ef589dcSJérôme Glisse if (percpu_ref_tryget_live(&devmem->ref)) { 10064ef589dcSJérôme Glisse dev_WARN(dev, "%s: page mapping is still live!\n", __func__); 10074ef589dcSJérôme Glisse percpu_ref_put(&devmem->ref); 10084ef589dcSJérôme Glisse } 10094ef589dcSJérôme Glisse 10104ef589dcSJérôme Glisse /* pages are dead and unused, undo the arch mapping */ 10114ef589dcSJérôme Glisse start_pfn = (resource->start & ~(PA_SECTION_SIZE - 1)) >> PAGE_SHIFT; 10124ef589dcSJérôme Glisse npages = ALIGN(resource_size(resource), PA_SECTION_SIZE) >> PAGE_SHIFT; 10134ef589dcSJérôme Glisse 10144ef589dcSJérôme Glisse page = pfn_to_page(start_pfn); 10154ef589dcSJérôme Glisse zone = page_zone(page); 10164ef589dcSJérôme Glisse 10174ef589dcSJérôme Glisse mem_hotplug_begin(); 1018d3df0a42SJérôme Glisse if (resource->desc == IORES_DESC_DEVICE_PRIVATE_MEMORY) 1019da024512SChristoph Hellwig __remove_pages(zone, start_pfn, npages, NULL); 1020d3df0a42SJérôme Glisse else 1021d3df0a42SJérôme Glisse arch_remove_memory(start_pfn << PAGE_SHIFT, 1022da024512SChristoph Hellwig npages << PAGE_SHIFT, NULL); 10234ef589dcSJérôme Glisse mem_hotplug_done(); 10244ef589dcSJérôme Glisse 10254ef589dcSJérôme Glisse hmm_devmem_radix_release(resource); 10264ef589dcSJérôme Glisse } 10274ef589dcSJérôme Glisse 10284ef589dcSJérôme Glisse static int hmm_devmem_pages_create(struct hmm_devmem *devmem) 10294ef589dcSJérôme Glisse { 10304ef589dcSJérôme Glisse resource_size_t key, align_start, align_size, align_end; 10314ef589dcSJérôme Glisse struct device *device = devmem->device; 10324ef589dcSJérôme Glisse int ret, nid, is_ram; 10334ef589dcSJérôme Glisse 10344ef589dcSJérôme Glisse align_start = devmem->resource->start & ~(PA_SECTION_SIZE - 1); 10354ef589dcSJérôme Glisse align_size = ALIGN(devmem->resource->start + 10364ef589dcSJérôme Glisse resource_size(devmem->resource), 10374ef589dcSJérôme Glisse PA_SECTION_SIZE) - align_start; 10384ef589dcSJérôme Glisse 10394ef589dcSJérôme Glisse is_ram = region_intersects(align_start, align_size, 10404ef589dcSJérôme Glisse IORESOURCE_SYSTEM_RAM, 10414ef589dcSJérôme Glisse IORES_DESC_NONE); 10424ef589dcSJérôme Glisse if (is_ram == REGION_MIXED) { 10434ef589dcSJérôme Glisse WARN_ONCE(1, "%s attempted on mixed region %pr\n", 10444ef589dcSJérôme Glisse __func__, devmem->resource); 10454ef589dcSJérôme Glisse return -ENXIO; 10464ef589dcSJérôme Glisse } 10474ef589dcSJérôme Glisse if (is_ram == REGION_INTERSECTS) 10484ef589dcSJérôme Glisse return -ENXIO; 10494ef589dcSJérôme Glisse 1050d3df0a42SJérôme Glisse if (devmem->resource->desc == IORES_DESC_DEVICE_PUBLIC_MEMORY) 1051d3df0a42SJérôme Glisse devmem->pagemap.type = MEMORY_DEVICE_PUBLIC; 1052d3df0a42SJérôme Glisse else 10534ef589dcSJérôme Glisse devmem->pagemap.type = MEMORY_DEVICE_PRIVATE; 1054d3df0a42SJérôme Glisse 1055e7744aa2SLogan Gunthorpe devmem->pagemap.res = *devmem->resource; 10564ef589dcSJérôme Glisse devmem->pagemap.page_fault = hmm_devmem_fault; 10574ef589dcSJérôme Glisse devmem->pagemap.page_free = hmm_devmem_free; 10584ef589dcSJérôme Glisse devmem->pagemap.dev = devmem->device; 10594ef589dcSJérôme Glisse devmem->pagemap.ref = &devmem->ref; 10604ef589dcSJérôme Glisse devmem->pagemap.data = devmem; 10614ef589dcSJérôme Glisse 10624ef589dcSJérôme Glisse mutex_lock(&hmm_devmem_lock); 10634ef589dcSJérôme Glisse align_end = align_start + align_size - 1; 10644ef589dcSJérôme Glisse for (key = align_start; key <= align_end; key += PA_SECTION_SIZE) { 10654ef589dcSJérôme Glisse struct hmm_devmem *dup; 10664ef589dcSJérôme Glisse 106718be460eSTejun Heo dup = radix_tree_lookup(&hmm_devmem_radix, 106818be460eSTejun Heo key >> PA_SECTION_SHIFT); 10694ef589dcSJérôme Glisse if (dup) { 10704ef589dcSJérôme Glisse dev_err(device, "%s: collides with mapping for %s\n", 10714ef589dcSJérôme Glisse __func__, dev_name(dup->device)); 10724ef589dcSJérôme Glisse mutex_unlock(&hmm_devmem_lock); 10734ef589dcSJérôme Glisse ret = -EBUSY; 10744ef589dcSJérôme Glisse goto error; 10754ef589dcSJérôme Glisse } 10764ef589dcSJérôme Glisse ret = radix_tree_insert(&hmm_devmem_radix, 10774ef589dcSJérôme Glisse key >> PA_SECTION_SHIFT, 10784ef589dcSJérôme Glisse devmem); 10794ef589dcSJérôme Glisse if (ret) { 10804ef589dcSJérôme Glisse dev_err(device, "%s: failed: %d\n", __func__, ret); 10814ef589dcSJérôme Glisse mutex_unlock(&hmm_devmem_lock); 10824ef589dcSJérôme Glisse goto error_radix; 10834ef589dcSJérôme Glisse } 10844ef589dcSJérôme Glisse } 10854ef589dcSJérôme Glisse mutex_unlock(&hmm_devmem_lock); 10864ef589dcSJérôme Glisse 10874ef589dcSJérôme Glisse nid = dev_to_node(device); 10884ef589dcSJérôme Glisse if (nid < 0) 10894ef589dcSJérôme Glisse nid = numa_mem_id(); 10904ef589dcSJérôme Glisse 10914ef589dcSJérôme Glisse mem_hotplug_begin(); 10924ef589dcSJérôme Glisse /* 10934ef589dcSJérôme Glisse * For device private memory we call add_pages() as we only need to 10944ef589dcSJérôme Glisse * allocate and initialize struct page for the device memory. More- 10954ef589dcSJérôme Glisse * over the device memory is un-accessible thus we do not want to 10964ef589dcSJérôme Glisse * create a linear mapping for the memory like arch_add_memory() 10974ef589dcSJérôme Glisse * would do. 1098d3df0a42SJérôme Glisse * 1099d3df0a42SJérôme Glisse * For device public memory, which is accesible by the CPU, we do 1100d3df0a42SJérôme Glisse * want the linear mapping and thus use arch_add_memory(). 11014ef589dcSJérôme Glisse */ 1102d3df0a42SJérôme Glisse if (devmem->pagemap.type == MEMORY_DEVICE_PUBLIC) 110324e6d5a5SChristoph Hellwig ret = arch_add_memory(nid, align_start, align_size, NULL, 110424e6d5a5SChristoph Hellwig false); 1105d3df0a42SJérôme Glisse else 11064ef589dcSJérôme Glisse ret = add_pages(nid, align_start >> PAGE_SHIFT, 110724e6d5a5SChristoph Hellwig align_size >> PAGE_SHIFT, NULL, false); 11084ef589dcSJérôme Glisse if (ret) { 11094ef589dcSJérôme Glisse mem_hotplug_done(); 11104ef589dcSJérôme Glisse goto error_add_memory; 11114ef589dcSJérôme Glisse } 11124ef589dcSJérôme Glisse move_pfn_range_to_zone(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], 11134ef589dcSJérôme Glisse align_start >> PAGE_SHIFT, 1114a99583e7SChristoph Hellwig align_size >> PAGE_SHIFT, NULL); 11154ef589dcSJérôme Glisse mem_hotplug_done(); 11164ef589dcSJérôme Glisse 1117966cf44fSAlexander Duyck /* 1118966cf44fSAlexander Duyck * Initialization of the pages has been deferred until now in order 1119966cf44fSAlexander Duyck * to allow us to do the work while not holding the hotplug lock. 1120966cf44fSAlexander Duyck */ 1121966cf44fSAlexander Duyck memmap_init_zone_device(&NODE_DATA(nid)->node_zones[ZONE_DEVICE], 1122966cf44fSAlexander Duyck align_start >> PAGE_SHIFT, 1123966cf44fSAlexander Duyck align_size >> PAGE_SHIFT, &devmem->pagemap); 11244ef589dcSJérôme Glisse 11254ef589dcSJérôme Glisse return 0; 11264ef589dcSJérôme Glisse 11274ef589dcSJérôme Glisse error_add_memory: 11284ef589dcSJérôme Glisse untrack_pfn(NULL, PHYS_PFN(align_start), align_size); 11294ef589dcSJérôme Glisse error_radix: 11304ef589dcSJérôme Glisse hmm_devmem_radix_release(devmem->resource); 11314ef589dcSJérôme Glisse error: 11324ef589dcSJérôme Glisse return ret; 11334ef589dcSJérôme Glisse } 11344ef589dcSJérôme Glisse 11354ef589dcSJérôme Glisse static int hmm_devmem_match(struct device *dev, void *data, void *match_data) 11364ef589dcSJérôme Glisse { 11374ef589dcSJérôme Glisse struct hmm_devmem *devmem = data; 11384ef589dcSJérôme Glisse 11394ef589dcSJérôme Glisse return devmem->resource == match_data; 11404ef589dcSJérôme Glisse } 11414ef589dcSJérôme Glisse 11424ef589dcSJérôme Glisse static void hmm_devmem_pages_remove(struct hmm_devmem *devmem) 11434ef589dcSJérôme Glisse { 11444ef589dcSJérôme Glisse devres_release(devmem->device, &hmm_devmem_release, 11454ef589dcSJérôme Glisse &hmm_devmem_match, devmem->resource); 11464ef589dcSJérôme Glisse } 11474ef589dcSJérôme Glisse 11484ef589dcSJérôme Glisse /* 11494ef589dcSJérôme Glisse * hmm_devmem_add() - hotplug ZONE_DEVICE memory for device memory 11504ef589dcSJérôme Glisse * 11514ef589dcSJérôme Glisse * @ops: memory event device driver callback (see struct hmm_devmem_ops) 11524ef589dcSJérôme Glisse * @device: device struct to bind the resource too 11534ef589dcSJérôme Glisse * @size: size in bytes of the device memory to add 11544ef589dcSJérôme Glisse * Returns: pointer to new hmm_devmem struct ERR_PTR otherwise 11554ef589dcSJérôme Glisse * 11564ef589dcSJérôme Glisse * This function first finds an empty range of physical address big enough to 11574ef589dcSJérôme Glisse * contain the new resource, and then hotplugs it as ZONE_DEVICE memory, which 11584ef589dcSJérôme Glisse * in turn allocates struct pages. It does not do anything beyond that; all 11594ef589dcSJérôme Glisse * events affecting the memory will go through the various callbacks provided 11604ef589dcSJérôme Glisse * by hmm_devmem_ops struct. 11614ef589dcSJérôme Glisse * 11624ef589dcSJérôme Glisse * Device driver should call this function during device initialization and 11634ef589dcSJérôme Glisse * is then responsible of memory management. HMM only provides helpers. 11644ef589dcSJérôme Glisse */ 11654ef589dcSJérôme Glisse struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops, 11664ef589dcSJérôme Glisse struct device *device, 11674ef589dcSJérôme Glisse unsigned long size) 11684ef589dcSJérôme Glisse { 11694ef589dcSJérôme Glisse struct hmm_devmem *devmem; 11704ef589dcSJérôme Glisse resource_size_t addr; 11714ef589dcSJérôme Glisse int ret; 11724ef589dcSJérôme Glisse 1173e7638488SDan Williams dev_pagemap_get_ops(); 11744ef589dcSJérôme Glisse 11754ef589dcSJérôme Glisse devmem = devres_alloc_node(&hmm_devmem_release, sizeof(*devmem), 11764ef589dcSJérôme Glisse GFP_KERNEL, dev_to_node(device)); 11774ef589dcSJérôme Glisse if (!devmem) 11784ef589dcSJérôme Glisse return ERR_PTR(-ENOMEM); 11794ef589dcSJérôme Glisse 11804ef589dcSJérôme Glisse init_completion(&devmem->completion); 11814ef589dcSJérôme Glisse devmem->pfn_first = -1UL; 11824ef589dcSJérôme Glisse devmem->pfn_last = -1UL; 11834ef589dcSJérôme Glisse devmem->resource = NULL; 11844ef589dcSJérôme Glisse devmem->device = device; 11854ef589dcSJérôme Glisse devmem->ops = ops; 11864ef589dcSJérôme Glisse 11874ef589dcSJérôme Glisse ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release, 11884ef589dcSJérôme Glisse 0, GFP_KERNEL); 11894ef589dcSJérôme Glisse if (ret) 11904ef589dcSJérôme Glisse goto error_percpu_ref; 11914ef589dcSJérôme Glisse 11924ef589dcSJérôme Glisse ret = devm_add_action(device, hmm_devmem_ref_exit, &devmem->ref); 11934ef589dcSJérôme Glisse if (ret) 11944ef589dcSJérôme Glisse goto error_devm_add_action; 11954ef589dcSJérôme Glisse 11964ef589dcSJérôme Glisse size = ALIGN(size, PA_SECTION_SIZE); 11974ef589dcSJérôme Glisse addr = min((unsigned long)iomem_resource.end, 11984ef589dcSJérôme Glisse (1UL << MAX_PHYSMEM_BITS) - 1); 11994ef589dcSJérôme Glisse addr = addr - size + 1UL; 12004ef589dcSJérôme Glisse 12014ef589dcSJérôme Glisse /* 12024ef589dcSJérôme Glisse * FIXME add a new helper to quickly walk resource tree and find free 12034ef589dcSJérôme Glisse * range 12044ef589dcSJérôme Glisse * 12054ef589dcSJérôme Glisse * FIXME what about ioport_resource resource ? 12064ef589dcSJérôme Glisse */ 12074ef589dcSJérôme Glisse for (; addr > size && addr >= iomem_resource.start; addr -= size) { 12084ef589dcSJérôme Glisse ret = region_intersects(addr, size, 0, IORES_DESC_NONE); 12094ef589dcSJérôme Glisse if (ret != REGION_DISJOINT) 12104ef589dcSJérôme Glisse continue; 12114ef589dcSJérôme Glisse 12124ef589dcSJérôme Glisse devmem->resource = devm_request_mem_region(device, addr, size, 12134ef589dcSJérôme Glisse dev_name(device)); 12144ef589dcSJérôme Glisse if (!devmem->resource) { 12154ef589dcSJérôme Glisse ret = -ENOMEM; 12164ef589dcSJérôme Glisse goto error_no_resource; 12174ef589dcSJérôme Glisse } 12184ef589dcSJérôme Glisse break; 12194ef589dcSJérôme Glisse } 12204ef589dcSJérôme Glisse if (!devmem->resource) { 12214ef589dcSJérôme Glisse ret = -ERANGE; 12224ef589dcSJérôme Glisse goto error_no_resource; 12234ef589dcSJérôme Glisse } 12244ef589dcSJérôme Glisse 12254ef589dcSJérôme Glisse devmem->resource->desc = IORES_DESC_DEVICE_PRIVATE_MEMORY; 12264ef589dcSJérôme Glisse devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT; 12274ef589dcSJérôme Glisse devmem->pfn_last = devmem->pfn_first + 12284ef589dcSJérôme Glisse (resource_size(devmem->resource) >> PAGE_SHIFT); 12294ef589dcSJérôme Glisse 12304ef589dcSJérôme Glisse ret = hmm_devmem_pages_create(devmem); 12314ef589dcSJérôme Glisse if (ret) 12324ef589dcSJérôme Glisse goto error_pages; 12334ef589dcSJérôme Glisse 12344ef589dcSJérôme Glisse devres_add(device, devmem); 12354ef589dcSJérôme Glisse 12364ef589dcSJérôme Glisse ret = devm_add_action(device, hmm_devmem_ref_kill, &devmem->ref); 12374ef589dcSJérôme Glisse if (ret) { 12384ef589dcSJérôme Glisse hmm_devmem_remove(devmem); 12394ef589dcSJérôme Glisse return ERR_PTR(ret); 12404ef589dcSJérôme Glisse } 12414ef589dcSJérôme Glisse 12424ef589dcSJérôme Glisse return devmem; 12434ef589dcSJérôme Glisse 12444ef589dcSJérôme Glisse error_pages: 12454ef589dcSJérôme Glisse devm_release_mem_region(device, devmem->resource->start, 12464ef589dcSJérôme Glisse resource_size(devmem->resource)); 12474ef589dcSJérôme Glisse error_no_resource: 12484ef589dcSJérôme Glisse error_devm_add_action: 12494ef589dcSJérôme Glisse hmm_devmem_ref_kill(&devmem->ref); 12504ef589dcSJérôme Glisse hmm_devmem_ref_exit(&devmem->ref); 12514ef589dcSJérôme Glisse error_percpu_ref: 12524ef589dcSJérôme Glisse devres_free(devmem); 12534ef589dcSJérôme Glisse return ERR_PTR(ret); 12544ef589dcSJérôme Glisse } 12554ef589dcSJérôme Glisse EXPORT_SYMBOL(hmm_devmem_add); 12564ef589dcSJérôme Glisse 1257d3df0a42SJérôme Glisse struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops, 1258d3df0a42SJérôme Glisse struct device *device, 1259d3df0a42SJérôme Glisse struct resource *res) 1260d3df0a42SJérôme Glisse { 1261d3df0a42SJérôme Glisse struct hmm_devmem *devmem; 1262d3df0a42SJérôme Glisse int ret; 1263d3df0a42SJérôme Glisse 1264d3df0a42SJérôme Glisse if (res->desc != IORES_DESC_DEVICE_PUBLIC_MEMORY) 1265d3df0a42SJérôme Glisse return ERR_PTR(-EINVAL); 1266d3df0a42SJérôme Glisse 1267e7638488SDan Williams dev_pagemap_get_ops(); 1268d3df0a42SJérôme Glisse 1269d3df0a42SJérôme Glisse devmem = devres_alloc_node(&hmm_devmem_release, sizeof(*devmem), 1270d3df0a42SJérôme Glisse GFP_KERNEL, dev_to_node(device)); 1271d3df0a42SJérôme Glisse if (!devmem) 1272d3df0a42SJérôme Glisse return ERR_PTR(-ENOMEM); 1273d3df0a42SJérôme Glisse 1274d3df0a42SJérôme Glisse init_completion(&devmem->completion); 1275d3df0a42SJérôme Glisse devmem->pfn_first = -1UL; 1276d3df0a42SJérôme Glisse devmem->pfn_last = -1UL; 1277d3df0a42SJérôme Glisse devmem->resource = res; 1278d3df0a42SJérôme Glisse devmem->device = device; 1279d3df0a42SJérôme Glisse devmem->ops = ops; 1280d3df0a42SJérôme Glisse 1281d3df0a42SJérôme Glisse ret = percpu_ref_init(&devmem->ref, &hmm_devmem_ref_release, 1282d3df0a42SJérôme Glisse 0, GFP_KERNEL); 1283d3df0a42SJérôme Glisse if (ret) 1284d3df0a42SJérôme Glisse goto error_percpu_ref; 1285d3df0a42SJérôme Glisse 1286d3df0a42SJérôme Glisse ret = devm_add_action(device, hmm_devmem_ref_exit, &devmem->ref); 1287d3df0a42SJérôme Glisse if (ret) 1288d3df0a42SJérôme Glisse goto error_devm_add_action; 1289d3df0a42SJérôme Glisse 1290d3df0a42SJérôme Glisse 1291d3df0a42SJérôme Glisse devmem->pfn_first = devmem->resource->start >> PAGE_SHIFT; 1292d3df0a42SJérôme Glisse devmem->pfn_last = devmem->pfn_first + 1293d3df0a42SJérôme Glisse (resource_size(devmem->resource) >> PAGE_SHIFT); 1294d3df0a42SJérôme Glisse 1295d3df0a42SJérôme Glisse ret = hmm_devmem_pages_create(devmem); 1296d3df0a42SJérôme Glisse if (ret) 1297d3df0a42SJérôme Glisse goto error_devm_add_action; 1298d3df0a42SJérôme Glisse 1299d3df0a42SJérôme Glisse devres_add(device, devmem); 1300d3df0a42SJérôme Glisse 1301d3df0a42SJérôme Glisse ret = devm_add_action(device, hmm_devmem_ref_kill, &devmem->ref); 1302d3df0a42SJérôme Glisse if (ret) { 1303d3df0a42SJérôme Glisse hmm_devmem_remove(devmem); 1304d3df0a42SJérôme Glisse return ERR_PTR(ret); 1305d3df0a42SJérôme Glisse } 1306d3df0a42SJérôme Glisse 1307d3df0a42SJérôme Glisse return devmem; 1308d3df0a42SJérôme Glisse 1309d3df0a42SJérôme Glisse error_devm_add_action: 1310d3df0a42SJérôme Glisse hmm_devmem_ref_kill(&devmem->ref); 1311d3df0a42SJérôme Glisse hmm_devmem_ref_exit(&devmem->ref); 1312d3df0a42SJérôme Glisse error_percpu_ref: 1313d3df0a42SJérôme Glisse devres_free(devmem); 1314d3df0a42SJérôme Glisse return ERR_PTR(ret); 1315d3df0a42SJérôme Glisse } 1316d3df0a42SJérôme Glisse EXPORT_SYMBOL(hmm_devmem_add_resource); 1317d3df0a42SJérôme Glisse 13184ef589dcSJérôme Glisse /* 13194ef589dcSJérôme Glisse * hmm_devmem_remove() - remove device memory (kill and free ZONE_DEVICE) 13204ef589dcSJérôme Glisse * 13214ef589dcSJérôme Glisse * @devmem: hmm_devmem struct use to track and manage the ZONE_DEVICE memory 13224ef589dcSJérôme Glisse * 13234ef589dcSJérôme Glisse * This will hot-unplug memory that was hotplugged by hmm_devmem_add on behalf 13244ef589dcSJérôme Glisse * of the device driver. It will free struct page and remove the resource that 13254ef589dcSJérôme Glisse * reserved the physical address range for this device memory. 13264ef589dcSJérôme Glisse */ 13274ef589dcSJérôme Glisse void hmm_devmem_remove(struct hmm_devmem *devmem) 13284ef589dcSJérôme Glisse { 13294ef589dcSJérôme Glisse resource_size_t start, size; 13304ef589dcSJérôme Glisse struct device *device; 1331d3df0a42SJérôme Glisse bool cdm = false; 13324ef589dcSJérôme Glisse 13334ef589dcSJérôme Glisse if (!devmem) 13344ef589dcSJérôme Glisse return; 13354ef589dcSJérôme Glisse 13364ef589dcSJérôme Glisse device = devmem->device; 13374ef589dcSJérôme Glisse start = devmem->resource->start; 13384ef589dcSJérôme Glisse size = resource_size(devmem->resource); 13394ef589dcSJérôme Glisse 1340d3df0a42SJérôme Glisse cdm = devmem->resource->desc == IORES_DESC_DEVICE_PUBLIC_MEMORY; 13414ef589dcSJérôme Glisse hmm_devmem_ref_kill(&devmem->ref); 13424ef589dcSJérôme Glisse hmm_devmem_ref_exit(&devmem->ref); 13434ef589dcSJérôme Glisse hmm_devmem_pages_remove(devmem); 13444ef589dcSJérôme Glisse 1345d3df0a42SJérôme Glisse if (!cdm) 13464ef589dcSJérôme Glisse devm_release_mem_region(device, start, size); 13474ef589dcSJérôme Glisse } 13484ef589dcSJérôme Glisse EXPORT_SYMBOL(hmm_devmem_remove); 1349858b54daSJérôme Glisse 1350858b54daSJérôme Glisse /* 1351858b54daSJérôme Glisse * A device driver that wants to handle multiple devices memory through a 1352858b54daSJérôme Glisse * single fake device can use hmm_device to do so. This is purely a helper 1353858b54daSJérôme Glisse * and it is not needed to make use of any HMM functionality. 1354858b54daSJérôme Glisse */ 1355858b54daSJérôme Glisse #define HMM_DEVICE_MAX 256 1356858b54daSJérôme Glisse 1357858b54daSJérôme Glisse static DECLARE_BITMAP(hmm_device_mask, HMM_DEVICE_MAX); 1358858b54daSJérôme Glisse static DEFINE_SPINLOCK(hmm_device_lock); 1359858b54daSJérôme Glisse static struct class *hmm_device_class; 1360858b54daSJérôme Glisse static dev_t hmm_device_devt; 1361858b54daSJérôme Glisse 1362858b54daSJérôme Glisse static void hmm_device_release(struct device *device) 1363858b54daSJérôme Glisse { 1364858b54daSJérôme Glisse struct hmm_device *hmm_device; 1365858b54daSJérôme Glisse 1366858b54daSJérôme Glisse hmm_device = container_of(device, struct hmm_device, device); 1367858b54daSJérôme Glisse spin_lock(&hmm_device_lock); 1368858b54daSJérôme Glisse clear_bit(hmm_device->minor, hmm_device_mask); 1369858b54daSJérôme Glisse spin_unlock(&hmm_device_lock); 1370858b54daSJérôme Glisse 1371858b54daSJérôme Glisse kfree(hmm_device); 1372858b54daSJérôme Glisse } 1373858b54daSJérôme Glisse 1374858b54daSJérôme Glisse struct hmm_device *hmm_device_new(void *drvdata) 1375858b54daSJérôme Glisse { 1376858b54daSJérôme Glisse struct hmm_device *hmm_device; 1377858b54daSJérôme Glisse 1378858b54daSJérôme Glisse hmm_device = kzalloc(sizeof(*hmm_device), GFP_KERNEL); 1379858b54daSJérôme Glisse if (!hmm_device) 1380858b54daSJérôme Glisse return ERR_PTR(-ENOMEM); 1381858b54daSJérôme Glisse 1382858b54daSJérôme Glisse spin_lock(&hmm_device_lock); 1383858b54daSJérôme Glisse hmm_device->minor = find_first_zero_bit(hmm_device_mask, HMM_DEVICE_MAX); 1384858b54daSJérôme Glisse if (hmm_device->minor >= HMM_DEVICE_MAX) { 1385858b54daSJérôme Glisse spin_unlock(&hmm_device_lock); 1386858b54daSJérôme Glisse kfree(hmm_device); 1387858b54daSJérôme Glisse return ERR_PTR(-EBUSY); 1388858b54daSJérôme Glisse } 1389858b54daSJérôme Glisse set_bit(hmm_device->minor, hmm_device_mask); 1390858b54daSJérôme Glisse spin_unlock(&hmm_device_lock); 1391858b54daSJérôme Glisse 1392858b54daSJérôme Glisse dev_set_name(&hmm_device->device, "hmm_device%d", hmm_device->minor); 1393858b54daSJérôme Glisse hmm_device->device.devt = MKDEV(MAJOR(hmm_device_devt), 1394858b54daSJérôme Glisse hmm_device->minor); 1395858b54daSJérôme Glisse hmm_device->device.release = hmm_device_release; 1396858b54daSJérôme Glisse dev_set_drvdata(&hmm_device->device, drvdata); 1397858b54daSJérôme Glisse hmm_device->device.class = hmm_device_class; 1398858b54daSJérôme Glisse device_initialize(&hmm_device->device); 1399858b54daSJérôme Glisse 1400858b54daSJérôme Glisse return hmm_device; 1401858b54daSJérôme Glisse } 1402858b54daSJérôme Glisse EXPORT_SYMBOL(hmm_device_new); 1403858b54daSJérôme Glisse 1404858b54daSJérôme Glisse void hmm_device_put(struct hmm_device *hmm_device) 1405858b54daSJérôme Glisse { 1406858b54daSJérôme Glisse put_device(&hmm_device->device); 1407858b54daSJérôme Glisse } 1408858b54daSJérôme Glisse EXPORT_SYMBOL(hmm_device_put); 1409858b54daSJérôme Glisse 1410858b54daSJérôme Glisse static int __init hmm_init(void) 1411858b54daSJérôme Glisse { 1412858b54daSJérôme Glisse int ret; 1413858b54daSJérôme Glisse 1414858b54daSJérôme Glisse ret = alloc_chrdev_region(&hmm_device_devt, 0, 1415858b54daSJérôme Glisse HMM_DEVICE_MAX, 1416858b54daSJérôme Glisse "hmm_device"); 1417858b54daSJérôme Glisse if (ret) 1418858b54daSJérôme Glisse return ret; 1419858b54daSJérôme Glisse 1420858b54daSJérôme Glisse hmm_device_class = class_create(THIS_MODULE, "hmm_device"); 1421858b54daSJérôme Glisse if (IS_ERR(hmm_device_class)) { 1422858b54daSJérôme Glisse unregister_chrdev_region(hmm_device_devt, HMM_DEVICE_MAX); 1423858b54daSJérôme Glisse return PTR_ERR(hmm_device_class); 1424858b54daSJérôme Glisse } 1425858b54daSJérôme Glisse return 0; 1426858b54daSJérôme Glisse } 1427858b54daSJérôme Glisse 1428858b54daSJérôme Glisse device_initcall(hmm_init); 1429df6ad698SJérôme Glisse #endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */ 1430