1/* 2 * Copyright(c) 2020 Cornelis Networks, Inc. 3 * Copyright(c) 2016 - 2017 Intel Corporation. 4 * 5 * This file is provided under a dual BSD/GPLv2 license. When using or 6 * redistributing this file, you may do so under either license. 7 * 8 * GPL LICENSE SUMMARY 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of version 2 of the GNU General Public License as 12 * published by the Free Software Foundation. 13 * 14 * This program is distributed in the hope that it will be useful, but 15 * WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 17 * General Public License for more details. 18 * 19 * BSD LICENSE 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 25 * - Redistributions of source code must retain the above copyright 26 * notice, this list of conditions and the following disclaimer. 27 * - Redistributions in binary form must reproduce the above copyright 28 * notice, this list of conditions and the following disclaimer in 29 * the documentation and/or other materials provided with the 30 * distribution. 31 * - Neither the name of Intel Corporation nor the names of its 32 * contributors may be used to endorse or promote products derived 33 * from this software without specific prior written permission. 34 * 35 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 36 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 37 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 38 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 39 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 40 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 41 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 42 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 43 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 44 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 45 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 46 * 47 */ 48#include <linux/list.h> 49#include <linux/rculist.h> 50#include <linux/mmu_notifier.h> 51#include <linux/interval_tree_generic.h> 52#include <linux/sched/mm.h> 53 54#include "mmu_rb.h" 55#include "trace.h" 56 57static unsigned long mmu_node_start(struct mmu_rb_node *); 58static unsigned long mmu_node_last(struct mmu_rb_node *); 59static int mmu_notifier_range_start(struct mmu_notifier *, 60 const struct mmu_notifier_range *); 61static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *, 62 unsigned long, unsigned long); 63static void release_immediate(struct kref *refcount); 64static void handle_remove(struct work_struct *work); 65 66static const struct mmu_notifier_ops mn_opts = { 67 .invalidate_range_start = mmu_notifier_range_start, 68}; 69 70INTERVAL_TREE_DEFINE(struct mmu_rb_node, node, unsigned long, __last, 71 mmu_node_start, mmu_node_last, static, __mmu_int_rb); 72 73static unsigned long mmu_node_start(struct mmu_rb_node *node) 74{ 75 return node->addr & PAGE_MASK; 76} 77 78static unsigned long mmu_node_last(struct mmu_rb_node *node) 79{ 80 return PAGE_ALIGN(node->addr + node->len) - 1; 81} 82 83int hfi1_mmu_rb_register(void *ops_arg, 84 struct mmu_rb_ops *ops, 85 struct workqueue_struct *wq, 86 struct mmu_rb_handler **handler) 87{ 88 struct mmu_rb_handler *h; 89 int ret; 90 91 h = kzalloc(sizeof(*h), GFP_KERNEL); 92 if (!h) 93 return -ENOMEM; 94 95 h->root = RB_ROOT_CACHED; 96 h->ops = ops; 97 h->ops_arg = ops_arg; 98 INIT_HLIST_NODE(&h->mn.hlist); 99 spin_lock_init(&h->lock); 100 h->mn.ops = &mn_opts; 101 INIT_WORK(&h->del_work, handle_remove); 102 INIT_LIST_HEAD(&h->del_list); 103 INIT_LIST_HEAD(&h->lru_list); 104 h->wq = wq; 105 106 ret = mmu_notifier_register(&h->mn, current->mm); 107 if (ret) { 108 kfree(h); 109 return ret; 110 } 111 112 *handler = h; 113 return 0; 114} 115 116void hfi1_mmu_rb_unregister(struct mmu_rb_handler *handler) 117{ 118 struct mmu_rb_node *rbnode; 119 struct rb_node *node; 120 unsigned long flags; 121 struct list_head del_list; 122 123 /* Prevent freeing of mm until we are completely finished. */ 124 mmgrab(handler->mn.mm); 125 126 /* Unregister first so we don't get any more notifications. */ 127 mmu_notifier_unregister(&handler->mn, handler->mn.mm); 128 129 /* 130 * Make sure the wq delete handler is finished running. It will not 131 * be triggered once the mmu notifiers are unregistered above. 132 */ 133 flush_work(&handler->del_work); 134 135 INIT_LIST_HEAD(&del_list); 136 137 spin_lock_irqsave(&handler->lock, flags); 138 while ((node = rb_first_cached(&handler->root))) { 139 rbnode = rb_entry(node, struct mmu_rb_node, node); 140 rb_erase_cached(node, &handler->root); 141 /* move from LRU list to delete list */ 142 list_move(&rbnode->list, &del_list); 143 } 144 spin_unlock_irqrestore(&handler->lock, flags); 145 146 while (!list_empty(&del_list)) { 147 rbnode = list_first_entry(&del_list, struct mmu_rb_node, list); 148 list_del(&rbnode->list); 149 kref_put(&rbnode->refcount, release_immediate); 150 } 151 152 /* Now the mm may be freed. */ 153 mmdrop(handler->mn.mm); 154 155 kfree(handler); 156} 157 158int hfi1_mmu_rb_insert(struct mmu_rb_handler *handler, 159 struct mmu_rb_node *mnode) 160{ 161 struct mmu_rb_node *node; 162 unsigned long flags; 163 int ret = 0; 164 165 trace_hfi1_mmu_rb_insert(mnode->addr, mnode->len); 166 167 if (current->mm != handler->mn.mm) 168 return -EPERM; 169 170 spin_lock_irqsave(&handler->lock, flags); 171 node = __mmu_rb_search(handler, mnode->addr, mnode->len); 172 if (node) { 173 ret = -EEXIST; 174 goto unlock; 175 } 176 __mmu_int_rb_insert(mnode, &handler->root); 177 list_add_tail(&mnode->list, &handler->lru_list); 178 mnode->handler = handler; 179unlock: 180 spin_unlock_irqrestore(&handler->lock, flags); 181 return ret; 182} 183 184/* Caller must hold handler lock */ 185struct mmu_rb_node *hfi1_mmu_rb_get_first(struct mmu_rb_handler *handler, 186 unsigned long addr, unsigned long len) 187{ 188 struct mmu_rb_node *node; 189 190 trace_hfi1_mmu_rb_search(addr, len); 191 node = __mmu_int_rb_iter_first(&handler->root, addr, (addr + len) - 1); 192 if (node) 193 list_move_tail(&node->list, &handler->lru_list); 194 return node; 195} 196 197/* Caller must hold handler lock */ 198static struct mmu_rb_node *__mmu_rb_search(struct mmu_rb_handler *handler, 199 unsigned long addr, 200 unsigned long len) 201{ 202 struct mmu_rb_node *node = NULL; 203 204 trace_hfi1_mmu_rb_search(addr, len); 205 if (!handler->ops->filter) { 206 node = __mmu_int_rb_iter_first(&handler->root, addr, 207 (addr + len) - 1); 208 } else { 209 for (node = __mmu_int_rb_iter_first(&handler->root, addr, 210 (addr + len) - 1); 211 node; 212 node = __mmu_int_rb_iter_next(node, addr, 213 (addr + len) - 1)) { 214 if (handler->ops->filter(node, addr, len)) 215 return node; 216 } 217 } 218 return node; 219} 220 221/* 222 * Must NOT call while holding mnode->handler->lock. 223 * mnode->handler->ops->remove() may sleep and mnode->handler->lock is a 224 * spinlock. 225 */ 226static void release_immediate(struct kref *refcount) 227{ 228 struct mmu_rb_node *mnode = 229 container_of(refcount, struct mmu_rb_node, refcount); 230 mnode->handler->ops->remove(mnode->handler->ops_arg, mnode); 231} 232 233/* Caller must hold mnode->handler->lock */ 234static void release_nolock(struct kref *refcount) 235{ 236 struct mmu_rb_node *mnode = 237 container_of(refcount, struct mmu_rb_node, refcount); 238 list_move(&mnode->list, &mnode->handler->del_list); 239 queue_work(mnode->handler->wq, &mnode->handler->del_work); 240} 241 242/* 243 * struct mmu_rb_node->refcount kref_put() callback. 244 * Adds mmu_rb_node to mmu_rb_node->handler->del_list and queues 245 * handler->del_work on handler->wq. 246 * Does not remove mmu_rb_node from handler->lru_list or handler->rb_root. 247 * Acquires mmu_rb_node->handler->lock; do not call while already holding 248 * handler->lock. 249 */ 250void hfi1_mmu_rb_release(struct kref *refcount) 251{ 252 struct mmu_rb_node *mnode = 253 container_of(refcount, struct mmu_rb_node, refcount); 254 struct mmu_rb_handler *handler = mnode->handler; 255 unsigned long flags; 256 257 spin_lock_irqsave(&handler->lock, flags); 258 list_move(&mnode->list, &mnode->handler->del_list); 259 spin_unlock_irqrestore(&handler->lock, flags); 260 queue_work(handler->wq, &handler->del_work); 261} 262 263void hfi1_mmu_rb_evict(struct mmu_rb_handler *handler, void *evict_arg) 264{ 265 struct mmu_rb_node *rbnode, *ptr; 266 struct list_head del_list; 267 unsigned long flags; 268 bool stop = false; 269 270 if (current->mm != handler->mn.mm) 271 return; 272 273 INIT_LIST_HEAD(&del_list); 274 275 spin_lock_irqsave(&handler->lock, flags); 276 list_for_each_entry_safe(rbnode, ptr, &handler->lru_list, list) { 277 /* refcount == 1 implies mmu_rb_handler has only rbnode ref */ 278 if (kref_read(&rbnode->refcount) > 1) 279 continue; 280 281 if (handler->ops->evict(handler->ops_arg, rbnode, evict_arg, 282 &stop)) { 283 __mmu_int_rb_remove(rbnode, &handler->root); 284 /* move from LRU list to delete list */ 285 list_move(&rbnode->list, &del_list); 286 } 287 if (stop) 288 break; 289 } 290 spin_unlock_irqrestore(&handler->lock, flags); 291 292 list_for_each_entry_safe(rbnode, ptr, &del_list, list) { 293 kref_put(&rbnode->refcount, release_immediate); 294 } 295} 296 297static int mmu_notifier_range_start(struct mmu_notifier *mn, 298 const struct mmu_notifier_range *range) 299{ 300 struct mmu_rb_handler *handler = 301 container_of(mn, struct mmu_rb_handler, mn); 302 struct rb_root_cached *root = &handler->root; 303 struct mmu_rb_node *node, *ptr = NULL; 304 unsigned long flags; 305 306 spin_lock_irqsave(&handler->lock, flags); 307 for (node = __mmu_int_rb_iter_first(root, range->start, range->end-1); 308 node; node = ptr) { 309 /* Guard against node removal. */ 310 ptr = __mmu_int_rb_iter_next(node, range->start, 311 range->end - 1); 312 trace_hfi1_mmu_mem_invalidate(node->addr, node->len); 313 /* Remove from rb tree and lru_list. */ 314 __mmu_int_rb_remove(node, root); 315 list_del_init(&node->list); 316 kref_put(&node->refcount, release_nolock); 317 } 318 spin_unlock_irqrestore(&handler->lock, flags); 319 320 return 0; 321} 322 323/* 324 * Work queue function to remove all nodes that have been queued up to 325 * be removed. The key feature is that mm->mmap_lock is not being held 326 * and the remove callback can sleep while taking it, if needed. 327 */ 328static void handle_remove(struct work_struct *work) 329{ 330 struct mmu_rb_handler *handler = container_of(work, 331 struct mmu_rb_handler, 332 del_work); 333 struct list_head del_list; 334 unsigned long flags; 335 struct mmu_rb_node *node; 336 337 /* remove anything that is queued to get removed */ 338 spin_lock_irqsave(&handler->lock, flags); 339 list_replace_init(&handler->del_list, &del_list); 340 spin_unlock_irqrestore(&handler->lock, flags); 341 342 while (!list_empty(&del_list)) { 343 node = list_first_entry(&del_list, struct mmu_rb_node, list); 344 list_del(&node->list); 345 handler->ops->remove(handler->ops_arg, node); 346 } 347} 348