1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright(c) 2020 Intel Corporation. */ 3 4 #include <linux/device.h> 5 #include <linux/slab.h> 6 #include <linux/idr.h> 7 #include <linux/pci.h> 8 #include <cxlmem.h> 9 #include "core.h" 10 11 static DECLARE_RWSEM(cxl_memdev_rwsem); 12 13 /* 14 * An entire PCI topology full of devices should be enough for any 15 * config 16 */ 17 #define CXL_MEM_MAX_DEVS 65536 18 19 static int cxl_mem_major; 20 static DEFINE_IDA(cxl_memdev_ida); 21 22 static void cxl_memdev_release(struct device *dev) 23 { 24 struct cxl_memdev *cxlmd = to_cxl_memdev(dev); 25 26 ida_free(&cxl_memdev_ida, cxlmd->id); 27 kfree(cxlmd); 28 } 29 30 static char *cxl_memdev_devnode(struct device *dev, umode_t *mode, kuid_t *uid, 31 kgid_t *gid) 32 { 33 return kasprintf(GFP_KERNEL, "cxl/%s", dev_name(dev)); 34 } 35 36 static ssize_t firmware_version_show(struct device *dev, 37 struct device_attribute *attr, char *buf) 38 { 39 struct cxl_memdev *cxlmd = to_cxl_memdev(dev); 40 struct cxl_dev_state *cxlds = cxlmd->cxlds; 41 42 return sysfs_emit(buf, "%.16s\n", cxlds->firmware_version); 43 } 44 static DEVICE_ATTR_RO(firmware_version); 45 46 static ssize_t payload_max_show(struct device *dev, 47 struct device_attribute *attr, char *buf) 48 { 49 struct cxl_memdev *cxlmd = to_cxl_memdev(dev); 50 struct cxl_dev_state *cxlds = cxlmd->cxlds; 51 52 return sysfs_emit(buf, "%zu\n", cxlds->payload_size); 53 } 54 static DEVICE_ATTR_RO(payload_max); 55 56 static ssize_t label_storage_size_show(struct device *dev, 57 struct device_attribute *attr, char *buf) 58 { 59 struct cxl_memdev *cxlmd = to_cxl_memdev(dev); 60 struct cxl_dev_state *cxlds = cxlmd->cxlds; 61 62 return sysfs_emit(buf, "%zu\n", cxlds->lsa_size); 63 } 64 static DEVICE_ATTR_RO(label_storage_size); 65 66 static ssize_t ram_size_show(struct device *dev, struct device_attribute *attr, 67 char *buf) 68 { 69 struct cxl_memdev *cxlmd = to_cxl_memdev(dev); 70 struct cxl_dev_state *cxlds = cxlmd->cxlds; 71 unsigned long long len = resource_size(&cxlds->ram_res); 72 73 return sysfs_emit(buf, "%#llx\n", len); 74 } 75 76 static struct device_attribute dev_attr_ram_size = 77 __ATTR(size, 0444, ram_size_show, NULL); 78 79 static ssize_t pmem_size_show(struct device *dev, struct device_attribute *attr, 80 char *buf) 81 { 82 struct cxl_memdev *cxlmd = to_cxl_memdev(dev); 83 struct cxl_dev_state *cxlds = cxlmd->cxlds; 84 unsigned long long len = resource_size(&cxlds->pmem_res); 85 86 return sysfs_emit(buf, "%#llx\n", len); 87 } 88 89 static struct device_attribute dev_attr_pmem_size = 90 __ATTR(size, 0444, pmem_size_show, NULL); 91 92 static ssize_t serial_show(struct device *dev, struct device_attribute *attr, 93 char *buf) 94 { 95 struct cxl_memdev *cxlmd = to_cxl_memdev(dev); 96 struct cxl_dev_state *cxlds = cxlmd->cxlds; 97 98 return sysfs_emit(buf, "%#llx\n", cxlds->serial); 99 } 100 static DEVICE_ATTR_RO(serial); 101 102 static ssize_t numa_node_show(struct device *dev, struct device_attribute *attr, 103 char *buf) 104 { 105 return sprintf(buf, "%d\n", dev_to_node(dev)); 106 } 107 static DEVICE_ATTR_RO(numa_node); 108 109 static struct attribute *cxl_memdev_attributes[] = { 110 &dev_attr_serial.attr, 111 &dev_attr_firmware_version.attr, 112 &dev_attr_payload_max.attr, 113 &dev_attr_label_storage_size.attr, 114 &dev_attr_numa_node.attr, 115 NULL, 116 }; 117 118 static struct attribute *cxl_memdev_pmem_attributes[] = { 119 &dev_attr_pmem_size.attr, 120 NULL, 121 }; 122 123 static struct attribute *cxl_memdev_ram_attributes[] = { 124 &dev_attr_ram_size.attr, 125 NULL, 126 }; 127 128 static umode_t cxl_memdev_visible(struct kobject *kobj, struct attribute *a, 129 int n) 130 { 131 if (!IS_ENABLED(CONFIG_NUMA) && a == &dev_attr_numa_node.attr) 132 return 0; 133 return a->mode; 134 } 135 136 static struct attribute_group cxl_memdev_attribute_group = { 137 .attrs = cxl_memdev_attributes, 138 .is_visible = cxl_memdev_visible, 139 }; 140 141 static struct attribute_group cxl_memdev_ram_attribute_group = { 142 .name = "ram", 143 .attrs = cxl_memdev_ram_attributes, 144 }; 145 146 static struct attribute_group cxl_memdev_pmem_attribute_group = { 147 .name = "pmem", 148 .attrs = cxl_memdev_pmem_attributes, 149 }; 150 151 static const struct attribute_group *cxl_memdev_attribute_groups[] = { 152 &cxl_memdev_attribute_group, 153 &cxl_memdev_ram_attribute_group, 154 &cxl_memdev_pmem_attribute_group, 155 NULL, 156 }; 157 158 static const struct device_type cxl_memdev_type = { 159 .name = "cxl_memdev", 160 .release = cxl_memdev_release, 161 .devnode = cxl_memdev_devnode, 162 .groups = cxl_memdev_attribute_groups, 163 }; 164 165 bool is_cxl_memdev(struct device *dev) 166 { 167 return dev->type == &cxl_memdev_type; 168 } 169 EXPORT_SYMBOL_NS_GPL(is_cxl_memdev, CXL); 170 171 /** 172 * set_exclusive_cxl_commands() - atomically disable user cxl commands 173 * @cxlds: The device state to operate on 174 * @cmds: bitmap of commands to mark exclusive 175 * 176 * Grab the cxl_memdev_rwsem in write mode to flush in-flight 177 * invocations of the ioctl path and then disable future execution of 178 * commands with the command ids set in @cmds. 179 */ 180 void set_exclusive_cxl_commands(struct cxl_dev_state *cxlds, unsigned long *cmds) 181 { 182 down_write(&cxl_memdev_rwsem); 183 bitmap_or(cxlds->exclusive_cmds, cxlds->exclusive_cmds, cmds, 184 CXL_MEM_COMMAND_ID_MAX); 185 up_write(&cxl_memdev_rwsem); 186 } 187 EXPORT_SYMBOL_NS_GPL(set_exclusive_cxl_commands, CXL); 188 189 /** 190 * clear_exclusive_cxl_commands() - atomically enable user cxl commands 191 * @cxlds: The device state to modify 192 * @cmds: bitmap of commands to mark available for userspace 193 */ 194 void clear_exclusive_cxl_commands(struct cxl_dev_state *cxlds, unsigned long *cmds) 195 { 196 down_write(&cxl_memdev_rwsem); 197 bitmap_andnot(cxlds->exclusive_cmds, cxlds->exclusive_cmds, cmds, 198 CXL_MEM_COMMAND_ID_MAX); 199 up_write(&cxl_memdev_rwsem); 200 } 201 EXPORT_SYMBOL_NS_GPL(clear_exclusive_cxl_commands, CXL); 202 203 static void cxl_memdev_shutdown(struct device *dev) 204 { 205 struct cxl_memdev *cxlmd = to_cxl_memdev(dev); 206 207 down_write(&cxl_memdev_rwsem); 208 cxlmd->cxlds = NULL; 209 up_write(&cxl_memdev_rwsem); 210 } 211 212 static void cxl_memdev_unregister(void *_cxlmd) 213 { 214 struct cxl_memdev *cxlmd = _cxlmd; 215 struct device *dev = &cxlmd->dev; 216 217 cxl_memdev_shutdown(dev); 218 cdev_device_del(&cxlmd->cdev, dev); 219 put_device(dev); 220 } 221 222 static void detach_memdev(struct work_struct *work) 223 { 224 struct cxl_memdev *cxlmd; 225 226 cxlmd = container_of(work, typeof(*cxlmd), detach_work); 227 device_release_driver(&cxlmd->dev); 228 put_device(&cxlmd->dev); 229 } 230 231 static struct lock_class_key cxl_memdev_key; 232 233 static struct cxl_memdev *cxl_memdev_alloc(struct cxl_dev_state *cxlds, 234 const struct file_operations *fops) 235 { 236 struct cxl_memdev *cxlmd; 237 struct device *dev; 238 struct cdev *cdev; 239 int rc; 240 241 cxlmd = kzalloc(sizeof(*cxlmd), GFP_KERNEL); 242 if (!cxlmd) 243 return ERR_PTR(-ENOMEM); 244 245 rc = ida_alloc_range(&cxl_memdev_ida, 0, CXL_MEM_MAX_DEVS, GFP_KERNEL); 246 if (rc < 0) 247 goto err; 248 cxlmd->id = rc; 249 250 dev = &cxlmd->dev; 251 device_initialize(dev); 252 lockdep_set_class(&dev->mutex, &cxl_memdev_key); 253 dev->parent = cxlds->dev; 254 dev->bus = &cxl_bus_type; 255 dev->devt = MKDEV(cxl_mem_major, cxlmd->id); 256 dev->type = &cxl_memdev_type; 257 device_set_pm_not_required(dev); 258 INIT_WORK(&cxlmd->detach_work, detach_memdev); 259 260 cdev = &cxlmd->cdev; 261 cdev_init(cdev, fops); 262 return cxlmd; 263 264 err: 265 kfree(cxlmd); 266 return ERR_PTR(rc); 267 } 268 269 static long __cxl_memdev_ioctl(struct cxl_memdev *cxlmd, unsigned int cmd, 270 unsigned long arg) 271 { 272 switch (cmd) { 273 case CXL_MEM_QUERY_COMMANDS: 274 return cxl_query_cmd(cxlmd, (void __user *)arg); 275 case CXL_MEM_SEND_COMMAND: 276 return cxl_send_cmd(cxlmd, (void __user *)arg); 277 default: 278 return -ENOTTY; 279 } 280 } 281 282 static long cxl_memdev_ioctl(struct file *file, unsigned int cmd, 283 unsigned long arg) 284 { 285 struct cxl_memdev *cxlmd = file->private_data; 286 int rc = -ENXIO; 287 288 down_read(&cxl_memdev_rwsem); 289 if (cxlmd->cxlds) 290 rc = __cxl_memdev_ioctl(cxlmd, cmd, arg); 291 up_read(&cxl_memdev_rwsem); 292 293 return rc; 294 } 295 296 static int cxl_memdev_open(struct inode *inode, struct file *file) 297 { 298 struct cxl_memdev *cxlmd = 299 container_of(inode->i_cdev, typeof(*cxlmd), cdev); 300 301 get_device(&cxlmd->dev); 302 file->private_data = cxlmd; 303 304 return 0; 305 } 306 307 static int cxl_memdev_release_file(struct inode *inode, struct file *file) 308 { 309 struct cxl_memdev *cxlmd = 310 container_of(inode->i_cdev, typeof(*cxlmd), cdev); 311 312 put_device(&cxlmd->dev); 313 314 return 0; 315 } 316 317 static const struct file_operations cxl_memdev_fops = { 318 .owner = THIS_MODULE, 319 .unlocked_ioctl = cxl_memdev_ioctl, 320 .open = cxl_memdev_open, 321 .release = cxl_memdev_release_file, 322 .compat_ioctl = compat_ptr_ioctl, 323 .llseek = noop_llseek, 324 }; 325 326 struct cxl_memdev *devm_cxl_add_memdev(struct cxl_dev_state *cxlds) 327 { 328 struct cxl_memdev *cxlmd; 329 struct device *dev; 330 struct cdev *cdev; 331 int rc; 332 333 cxlmd = cxl_memdev_alloc(cxlds, &cxl_memdev_fops); 334 if (IS_ERR(cxlmd)) 335 return cxlmd; 336 337 dev = &cxlmd->dev; 338 rc = dev_set_name(dev, "mem%d", cxlmd->id); 339 if (rc) 340 goto err; 341 342 /* 343 * Activate ioctl operations, no cxl_memdev_rwsem manipulation 344 * needed as this is ordered with cdev_add() publishing the device. 345 */ 346 cxlmd->cxlds = cxlds; 347 348 cdev = &cxlmd->cdev; 349 rc = cdev_device_add(cdev, dev); 350 if (rc) 351 goto err; 352 353 rc = devm_add_action_or_reset(cxlds->dev, cxl_memdev_unregister, cxlmd); 354 if (rc) 355 return ERR_PTR(rc); 356 return cxlmd; 357 358 err: 359 /* 360 * The cdev was briefly live, shutdown any ioctl operations that 361 * saw that state. 362 */ 363 cxl_memdev_shutdown(dev); 364 put_device(dev); 365 return ERR_PTR(rc); 366 } 367 EXPORT_SYMBOL_NS_GPL(devm_cxl_add_memdev, CXL); 368 369 __init int cxl_memdev_init(void) 370 { 371 dev_t devt; 372 int rc; 373 374 rc = alloc_chrdev_region(&devt, 0, CXL_MEM_MAX_DEVS, "cxl"); 375 if (rc) 376 return rc; 377 378 cxl_mem_major = MAJOR(devt); 379 380 return 0; 381 } 382 383 void cxl_memdev_exit(void) 384 { 385 unregister_chrdev_region(MKDEV(cxl_mem_major, 0), CXL_MEM_MAX_DEVS); 386 } 387