drivers/base/firmware_loader/sysfs.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <linux/highmem.h>
   4 #include <linux/module.h>
   5 #include <linux/security.h>
   6 #include <linux/slab.h>
   7 #include <linux/types.h>
   8
   9 #include "sysfs.h"
  10
  11 /*
  12  * sysfs support for firmware loader
  13  */
  14
  15 void __fw_load_abort(struct fw_priv *fw_priv)
  16 {
  17         /*
  18          * There is a small window in which user can write to 'loading'
  19          * between loading done/aborted and disappearance of 'loading'
  20          */
  21         if (fw_state_is_aborted(fw_priv) || fw_state_is_done(fw_priv))
  22                 return;
  23
  24         fw_state_aborted(fw_priv);
  25 }
  26
  27 #ifdef CONFIG_FW_LOADER_USER_HELPER
  28 static ssize_t timeout_show(const struct class *class, const struct class_attribute *attr,
  29                             char *buf)
  30 {
  31         return sysfs_emit(buf, "%d\n", __firmware_loading_timeout());
  32 }
  33
  34 /**
  35  * timeout_store() - set number of seconds to wait for firmware
  36  * @class: device class pointer
  37  * @attr: device attribute pointer
  38  * @buf: buffer to scan for timeout value
  39  * @count: number of bytes in @buf
  40  *
  41  *      Sets the number of seconds to wait for the firmware.  Once
  42  *      this expires an error will be returned to the driver and no
  43  *      firmware will be provided.
  44  *
  45  *      Note: zero means 'wait forever'.
  46  **/
  47 static ssize_t timeout_store(const struct class *class, const struct class_attribute *attr,
  48                              const char *buf, size_t count)
  49 {
  50         int tmp_loading_timeout = simple_strtol(buf, NULL, 10);
  51
  52         if (tmp_loading_timeout < 0)
  53                 tmp_loading_timeout = 0;
  54
  55         __fw_fallback_set_timeout(tmp_loading_timeout);
  56
  57         return count;
  58 }
  59 static CLASS_ATTR_RW(timeout);
  60
  61 static struct attribute *firmware_class_attrs[] = {
  62         &class_attr_timeout.attr,
  63         NULL,
  64 };
  65 ATTRIBUTE_GROUPS(firmware_class);
  66
  67 static int do_firmware_uevent(const struct fw_sysfs *fw_sysfs, struct kobj_uevent_env *env)
  68 {
  69         if (add_uevent_var(env, "FIRMWARE=%s", fw_sysfs->fw_priv->fw_name))
  70                 return -ENOMEM;
  71         if (add_uevent_var(env, "TIMEOUT=%i", __firmware_loading_timeout()))
  72                 return -ENOMEM;
  73         if (add_uevent_var(env, "ASYNC=%d", fw_sysfs->nowait))
  74                 return -ENOMEM;
  75
  76         return 0;
  77 }
  78
  79 static int firmware_uevent(const struct device *dev, struct kobj_uevent_env *env)
  80 {
  81         const struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
  82         int err = 0;
  83
  84         mutex_lock(&fw_lock);
  85         if (fw_sysfs->fw_priv)
  86                 err = do_firmware_uevent(fw_sysfs, env);
  87         mutex_unlock(&fw_lock);
  88         return err;
  89 }
  90 #endif /* CONFIG_FW_LOADER_USER_HELPER */
  91
  92 static void fw_dev_release(struct device *dev)
  93 {
  94         struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
  95
  96         if (fw_sysfs->fw_upload_priv)
  97                 fw_upload_free(fw_sysfs);
  98
  99         kfree(fw_sysfs);
 100 }
 101
 102 static struct class firmware_class = {
 103         .name           = "firmware",
 104 #ifdef CONFIG_FW_LOADER_USER_HELPER
 105         .class_groups   = firmware_class_groups,
 106         .dev_uevent     = firmware_uevent,
 107 #endif
 108         .dev_release    = fw_dev_release,
 109 };
 110
 111 int register_sysfs_loader(void)
 112 {
 113         int ret = class_register(&firmware_class);
 114
 115         if (ret != 0)
 116                 return ret;
 117         return register_firmware_config_sysctl();
 118 }
 119
 120 void unregister_sysfs_loader(void)
 121 {
 122         unregister_firmware_config_sysctl();
 123         class_unregister(&firmware_class);
 124 }
 125
 126 static ssize_t firmware_loading_show(struct device *dev,
 127                                      struct device_attribute *attr, char *buf)
 128 {
 129         struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
 130         int loading = 0;
 131
 132         mutex_lock(&fw_lock);
 133         if (fw_sysfs->fw_priv)
 134                 loading = fw_state_is_loading(fw_sysfs->fw_priv);
 135         mutex_unlock(&fw_lock);
 136
 137         return sysfs_emit(buf, "%d\n", loading);
 138 }
 139
 140 /**
 141  * firmware_loading_store() - set value in the 'loading' control file
 142  * @dev: device pointer
 143  * @attr: device attribute pointer
 144  * @buf: buffer to scan for loading control value
 145  * @count: number of bytes in @buf
 146  *
 147  *      The relevant values are:
 148  *
 149  *       1: Start a load, discarding any previous partial load.
 150  *       0: Conclude the load and hand the data to the driver code.
 151  *      -1: Conclude the load with an error and discard any written data.
 152  **/
 153 static ssize_t firmware_loading_store(struct device *dev,
 154                                       struct device_attribute *attr,
 155                                       const char *buf, size_t count)
 156 {
 157         struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
 158         struct fw_priv *fw_priv;
 159         ssize_t written = count;
 160         int loading = simple_strtol(buf, NULL, 10);
 161
 162         mutex_lock(&fw_lock);
 163         fw_priv = fw_sysfs->fw_priv;
 164         if (fw_state_is_aborted(fw_priv) || fw_state_is_done(fw_priv))
 165                 goto out;
 166
 167         switch (loading) {
 168         case 1:
 169                 /* discarding any previous partial load */
 170                 fw_free_paged_buf(fw_priv);
 171                 fw_state_start(fw_priv);
 172                 break;
 173         case 0:
 174                 if (fw_state_is_loading(fw_priv)) {
 175                         int rc;
 176
 177                         /*
 178                          * Several loading requests may be pending on
 179                          * one same firmware buf, so let all requests
 180                          * see the mapped 'buf->data' once the loading
 181                          * is completed.
 182                          */
 183                         rc = fw_map_paged_buf(fw_priv);
 184                         if (rc)
 185                                 dev_err(dev, "%s: map pages failed\n",
 186                                         __func__);
 187                         else
 188                                 rc = security_kernel_post_load_data(fw_priv->data,
 189                                                                     fw_priv->size,
 190                                                                     LOADING_FIRMWARE,
 191                                                                     "blob");
 192
 193                         /*
 194                          * Same logic as fw_load_abort, only the DONE bit
 195                          * is ignored and we set ABORT only on failure.
 196                          */
 197                         if (rc) {
 198                                 fw_state_aborted(fw_priv);
 199                                 written = rc;
 200                         } else {
 201                                 fw_state_done(fw_priv);
 202
 203                                 /*
 204                                  * If this is a user-initiated firmware upload
 205                                  * then start the upload in a worker thread now.
 206                                  */
 207                                 rc = fw_upload_start(fw_sysfs);
 208                                 if (rc)
 209                                         written = rc;
 210                         }
 211                         break;
 212                 }
 213                 fallthrough;
 214         default:
 215                 dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);
 216                 fallthrough;
 217         case -1:
 218                 fw_load_abort(fw_sysfs);
 219                 if (fw_sysfs->fw_upload_priv)
 220                         fw_state_init(fw_sysfs->fw_priv);
 221
 222                 break;
 223         }
 224 out:
 225         mutex_unlock(&fw_lock);
 226         return written;
 227 }
 228
 229 DEVICE_ATTR(loading, 0644, firmware_loading_show, firmware_loading_store);
 230
 231 static void firmware_rw_data(struct fw_priv *fw_priv, char *buffer,
 232                              loff_t offset, size_t count, bool read)
 233 {
 234         if (read)
 235                 memcpy(buffer, fw_priv->data + offset, count);
 236         else
 237                 memcpy(fw_priv->data + offset, buffer, count);
 238 }
 239
 240 static void firmware_rw(struct fw_priv *fw_priv, char *buffer,
 241                         loff_t offset, size_t count, bool read)
 242 {
 243         while (count) {
 244                 int page_nr = offset >> PAGE_SHIFT;
 245                 int page_ofs = offset & (PAGE_SIZE - 1);
 246                 int page_cnt = min_t(size_t, PAGE_SIZE - page_ofs, count);
 247
 248                 if (read)
 249                         memcpy_from_page(buffer, fw_priv->pages[page_nr],
 250                                          page_ofs, page_cnt);
 251                 else
 252                         memcpy_to_page(fw_priv->pages[page_nr], page_ofs,
 253                                        buffer, page_cnt);
 254
 255                 buffer += page_cnt;
 256                 offset += page_cnt;
 257                 count -= page_cnt;
 258         }
 259 }
 260
 261 static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj,
 262                                   struct bin_attribute *bin_attr,
 263                                   char *buffer, loff_t offset, size_t count)
 264 {
 265         struct device *dev = kobj_to_dev(kobj);
 266         struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
 267         struct fw_priv *fw_priv;
 268         ssize_t ret_count;
 269
 270         mutex_lock(&fw_lock);
 271         fw_priv = fw_sysfs->fw_priv;
 272         if (!fw_priv || fw_state_is_done(fw_priv)) {
 273                 ret_count = -ENODEV;
 274                 goto out;
 275         }
 276         if (offset > fw_priv->size) {
 277                 ret_count = 0;
 278                 goto out;
 279         }
 280         if (count > fw_priv->size - offset)
 281                 count = fw_priv->size - offset;
 282
 283         ret_count = count;
 284
 285         if (fw_priv->data)
 286                 firmware_rw_data(fw_priv, buffer, offset, count, true);
 287         else
 288                 firmware_rw(fw_priv, buffer, offset, count, true);
 289
 290 out:
 291         mutex_unlock(&fw_lock);
 292         return ret_count;
 293 }
 294
 295 static int fw_realloc_pages(struct fw_sysfs *fw_sysfs, int min_size)
 296 {
 297         int err;
 298
 299         err = fw_grow_paged_buf(fw_sysfs->fw_priv,
 300                                 PAGE_ALIGN(min_size) >> PAGE_SHIFT);
 301         if (err)
 302                 fw_load_abort(fw_sysfs);
 303         return err;
 304 }
 305
 306 /**
 307  * firmware_data_write() - write method for firmware
 308  * @filp: open sysfs file
 309  * @kobj: kobject for the device
 310  * @bin_attr: bin_attr structure
 311  * @buffer: buffer being written
 312  * @offset: buffer offset for write in total data store area
 313  * @count: buffer size
 314  *
 315  *      Data written to the 'data' attribute will be later handed to
 316  *      the driver as a firmware image.
 317  **/
 318 static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj,
 319                                    struct bin_attribute *bin_attr,
 320                                    char *buffer, loff_t offset, size_t count)
 321 {
 322         struct device *dev = kobj_to_dev(kobj);
 323         struct fw_sysfs *fw_sysfs = to_fw_sysfs(dev);
 324         struct fw_priv *fw_priv;
 325         ssize_t retval;
 326
 327         if (!capable(CAP_SYS_RAWIO))
 328                 return -EPERM;
 329
 330         mutex_lock(&fw_lock);
 331         fw_priv = fw_sysfs->fw_priv;
 332         if (!fw_priv || fw_state_is_done(fw_priv)) {
 333                 retval = -ENODEV;
 334                 goto out;
 335         }
 336
 337         if (fw_priv->data) {
 338                 if (offset + count > fw_priv->allocated_size) {
 339                         retval = -ENOMEM;
 340                         goto out;
 341                 }
 342                 firmware_rw_data(fw_priv, buffer, offset, count, false);
 343                 retval = count;
 344         } else {
 345                 retval = fw_realloc_pages(fw_sysfs, offset + count);
 346                 if (retval)
 347                         goto out;
 348
 349                 retval = count;
 350                 firmware_rw(fw_priv, buffer, offset, count, false);
 351         }
 352
 353         fw_priv->size = max_t(size_t, offset + count, fw_priv->size);
 354 out:
 355         mutex_unlock(&fw_lock);
 356         return retval;
 357 }
 358
 359 static struct bin_attribute firmware_attr_data = {
 360         .attr = { .name = "data", .mode = 0644 },
 361         .size = 0,
 362         .read = firmware_data_read,
 363         .write = firmware_data_write,
 364 };
 365
 366 static struct attribute *fw_dev_attrs[] = {
 367         &dev_attr_loading.attr,
 368 #ifdef CONFIG_FW_UPLOAD
 369         &dev_attr_cancel.attr,
 370         &dev_attr_status.attr,
 371         &dev_attr_error.attr,
 372         &dev_attr_remaining_size.attr,
 373 #endif
 374         NULL
 375 };
 376
 377 static struct bin_attribute *fw_dev_bin_attrs[] = {
 378         &firmware_attr_data,
 379         NULL
 380 };
 381
 382 static const struct attribute_group fw_dev_attr_group = {
 383         .attrs = fw_dev_attrs,
 384         .bin_attrs = fw_dev_bin_attrs,
 385 #ifdef CONFIG_FW_UPLOAD
 386         .is_visible = fw_upload_is_visible,
 387 #endif
 388 };
 389
 390 static const struct attribute_group *fw_dev_attr_groups[] = {
 391         &fw_dev_attr_group,
 392         NULL
 393 };
 394
 395 struct fw_sysfs *
 396 fw_create_instance(struct firmware *firmware, const char *fw_name,
 397                    struct device *device, u32 opt_flags)
 398 {
 399         struct fw_sysfs *fw_sysfs;
 400         struct device *f_dev;
 401
 402         fw_sysfs = kzalloc(sizeof(*fw_sysfs), GFP_KERNEL);
 403         if (!fw_sysfs) {
 404                 fw_sysfs = ERR_PTR(-ENOMEM);
 405                 goto exit;
 406         }
 407
 408         fw_sysfs->nowait = !!(opt_flags & FW_OPT_NOWAIT);
 409         fw_sysfs->fw = firmware;
 410         f_dev = &fw_sysfs->dev;
 411
 412         device_initialize(f_dev);
 413         dev_set_name(f_dev, "%s", fw_name);
 414         f_dev->parent = device;
 415         f_dev->class = &firmware_class;
 416         f_dev->groups = fw_dev_attr_groups;
 417 exit:
 418         return fw_sysfs;
 419 }