drivers/cxl/core/memdev.c

   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 = range_len(&cxlds->ram_range);
  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 = range_len(&cxlds->pmem_range);
  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 }