drivers/staging/gasket/gasket_core.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Gasket generic driver framework. This file contains the implementation
   4  * for the Gasket generic driver framework - the functionality that is common
   5  * across Gasket devices.
   6  *
   7  * Copyright (C) 2018 Google, Inc.
   8  */
   9
  10 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  11
  12 #include "gasket_core.h"
  13
  14 #include "gasket_interrupt.h"
  15 #include "gasket_ioctl.h"
  16 #include "gasket_page_table.h"
  17 #include "gasket_sysfs.h"
  18
  19 #include <linux/capability.h>
  20 #include <linux/compiler.h>
  21 #include <linux/delay.h>
  22 #include <linux/device.h>
  23 #include <linux/fs.h>
  24 #include <linux/init.h>
  25 #include <linux/of.h>
  26 #include <linux/pid_namespace.h>
  27 #include <linux/printk.h>
  28 #include <linux/sched.h>
  29
  30 #ifdef GASKET_KERNEL_TRACE_SUPPORT
  31 #define CREATE_TRACE_POINTS
  32 #include <trace/events/gasket_mmap.h>
  33 #else
  34 #define trace_gasket_mmap_exit(x)
  35 #define trace_gasket_mmap_entry(x, ...)
  36 #endif
  37
  38 /*
  39  * "Private" members of gasket_driver_desc.
  40  *
  41  * Contains internal per-device type tracking data, i.e., data not appropriate
  42  * as part of the public interface for the generic framework.
  43  */
  44 struct gasket_internal_desc {
  45         /* Device-specific-driver-provided configuration information. */
  46         const struct gasket_driver_desc *driver_desc;
  47
  48         /* Protects access to per-driver data (i.e. this structure). */
  49         struct mutex mutex;
  50
  51         /* Kernel-internal device class. */
  52         struct class *class;
  53
  54         /* Instantiated / present devices of this type. */
  55         struct gasket_dev *devs[GASKET_DEV_MAX];
  56 };
  57
  58 /* do_map_region() needs be able to return more than just true/false. */
  59 enum do_map_region_status {
  60         /* The region was successfully mapped. */
  61         DO_MAP_REGION_SUCCESS,
  62
  63         /* Attempted to map region and failed. */
  64         DO_MAP_REGION_FAILURE,
  65
  66         /* The requested region to map was not part of a mappable region. */
  67         DO_MAP_REGION_INVALID,
  68 };
  69
  70 /* Global data definitions. */
  71 /* Mutex - only for framework-wide data. Other data should be protected by
  72  * finer-grained locks.
  73  */
  74 static DEFINE_MUTEX(g_mutex);
  75
  76 /* List of all registered device descriptions & their supporting data. */
  77 static struct gasket_internal_desc g_descs[GASKET_FRAMEWORK_DESC_MAX];
  78
  79 /* Mapping of statuses to human-readable strings. Must end with {0,NULL}. */
  80 static const struct gasket_num_name gasket_status_name_table[] = {
  81         { GASKET_STATUS_DEAD, "DEAD" },
  82         { GASKET_STATUS_ALIVE, "ALIVE" },
  83         { GASKET_STATUS_LAMED, "LAMED" },
  84         { GASKET_STATUS_DRIVER_EXIT, "DRIVER_EXITING" },
  85         { 0, NULL },
  86 };
  87
  88 /* Enumeration of the automatic Gasket framework sysfs nodes. */
  89 enum gasket_sysfs_attribute_type {
  90         ATTR_BAR_OFFSETS,
  91         ATTR_BAR_SIZES,
  92         ATTR_DRIVER_VERSION,
  93         ATTR_FRAMEWORK_VERSION,
  94         ATTR_DEVICE_TYPE,
  95         ATTR_HARDWARE_REVISION,
  96         ATTR_PCI_ADDRESS,
  97         ATTR_STATUS,
  98         ATTR_IS_DEVICE_OWNED,
  99         ATTR_DEVICE_OWNER,
 100         ATTR_WRITE_OPEN_COUNT,
 101         ATTR_RESET_COUNT,
 102         ATTR_USER_MEM_RANGES
 103 };
 104
 105 /* Perform a standard Gasket callback. */
 106 static inline int
 107 check_and_invoke_callback(struct gasket_dev *gasket_dev,
 108                           int (*cb_function)(struct gasket_dev *))
 109 {
 110         int ret = 0;
 111
 112         if (cb_function) {
 113                 mutex_lock(&gasket_dev->mutex);
 114                 ret = cb_function(gasket_dev);
 115                 mutex_unlock(&gasket_dev->mutex);
 116         }
 117         return ret;
 118 }
 119
 120 /* Perform a standard Gasket callback without grabbing gasket_dev->mutex. */
 121 static inline int
 122 gasket_check_and_invoke_callback_nolock(struct gasket_dev *gasket_dev,
 123                                         int (*cb_function)(struct gasket_dev *))
 124 {
 125         int ret = 0;
 126
 127         if (cb_function)
 128                 ret = cb_function(gasket_dev);
 129         return ret;
 130 }
 131
 132 /*
 133  * Return nonzero if the gasket_cdev_info is owned by the current thread group
 134  * ID.
 135  */
 136 static int gasket_owned_by_current_tgid(struct gasket_cdev_info *info)
 137 {
 138         return (info->ownership.is_owned &&
 139                 (info->ownership.owner == current->tgid));
 140 }
 141
 142 /*
 143  * Find the next free gasket_internal_dev slot.
 144  *
 145  * Returns the located slot number on success or a negative number on failure.
 146  */
 147 static int gasket_find_dev_slot(struct gasket_internal_desc *internal_desc,
 148                                 const char *kobj_name)
 149 {
 150         int i;
 151
 152         mutex_lock(&internal_desc->mutex);
 153
 154         /* Search for a previous instance of this device. */
 155         for (i = 0; i < GASKET_DEV_MAX; i++) {
 156                 if (internal_desc->devs[i] &&
 157                     strcmp(internal_desc->devs[i]->kobj_name, kobj_name) == 0) {
 158                         pr_err("Duplicate device %s\n", kobj_name);
 159                         mutex_unlock(&internal_desc->mutex);
 160                         return -EBUSY;
 161                 }
 162         }
 163
 164         /* Find a free device slot. */
 165         for (i = 0; i < GASKET_DEV_MAX; i++) {
 166                 if (!internal_desc->devs[i])
 167                         break;
 168         }
 169
 170         if (i == GASKET_DEV_MAX) {
 171                 pr_err("Too many registered devices; max %d\n", GASKET_DEV_MAX);
 172                 mutex_unlock(&internal_desc->mutex);
 173                 return -EBUSY;
 174         }
 175
 176         mutex_unlock(&internal_desc->mutex);
 177         return i;
 178 }
 179
 180 /*
 181  * Allocate and initialize a Gasket device structure, add the device to the
 182  * device list.
 183  *
 184  * Returns 0 if successful, a negative error code otherwise.
 185  */
 186 static int gasket_alloc_dev(struct gasket_internal_desc *internal_desc,
 187                             struct device *parent, struct gasket_dev **pdev)
 188 {
 189         int dev_idx;
 190         const struct gasket_driver_desc *driver_desc =
 191                 internal_desc->driver_desc;
 192         struct gasket_dev *gasket_dev;
 193         struct gasket_cdev_info *dev_info;
 194         const char *parent_name = dev_name(parent);
 195
 196         pr_debug("Allocating a Gasket device, parent %s.\n", parent_name);
 197
 198         *pdev = NULL;
 199
 200         dev_idx = gasket_find_dev_slot(internal_desc, parent_name);
 201         if (dev_idx < 0)
 202                 return dev_idx;
 203
 204         gasket_dev = *pdev = kzalloc(sizeof(*gasket_dev), GFP_KERNEL);
 205         if (!gasket_dev) {
 206                 pr_err("no memory for device, parent %s\n", parent_name);
 207                 return -ENOMEM;
 208         }
 209         internal_desc->devs[dev_idx] = gasket_dev;
 210
 211         mutex_init(&gasket_dev->mutex);
 212
 213         gasket_dev->internal_desc = internal_desc;
 214         gasket_dev->dev_idx = dev_idx;
 215         snprintf(gasket_dev->kobj_name, GASKET_NAME_MAX, "%s", parent_name);
 216         gasket_dev->dev = get_device(parent);
 217         /* gasket_bar_data is uninitialized. */
 218         gasket_dev->num_page_tables = driver_desc->num_page_tables;
 219         /* max_page_table_size and *page table are uninit'ed */
 220         /* interrupt_data is not initialized. */
 221         /* status is 0, or GASKET_STATUS_DEAD */
 222
 223         dev_info = &gasket_dev->dev_info;
 224         snprintf(dev_info->name, GASKET_NAME_MAX, "%s_%u", driver_desc->name,
 225                  gasket_dev->dev_idx);
 226         dev_info->devt =
 227                 MKDEV(driver_desc->major, driver_desc->minor +
 228                       gasket_dev->dev_idx);
 229         dev_info->device =
 230                 device_create(internal_desc->class, parent, dev_info->devt,
 231                               gasket_dev, dev_info->name);
 232
 233         /* cdev has not yet been added; cdev_added is 0 */
 234         dev_info->gasket_dev_ptr = gasket_dev;
 235         /* ownership is all 0, indicating no owner or opens. */
 236
 237         return 0;
 238 }
 239
 240 /* Free a Gasket device. */
 241 static void gasket_free_dev(struct gasket_dev *gasket_dev)
 242 {
 243         struct gasket_internal_desc *internal_desc = gasket_dev->internal_desc;
 244
 245         mutex_lock(&internal_desc->mutex);
 246         internal_desc->devs[gasket_dev->dev_idx] = NULL;
 247         mutex_unlock(&internal_desc->mutex);
 248         put_device(gasket_dev->dev);
 249         kfree(gasket_dev);
 250 }
 251
 252 /*
 253  * Maps the specified bar into kernel space.
 254  *
 255  * Returns 0 on success, a negative error code otherwise.
 256  * A zero-sized BAR will not be mapped, but is not an error.
 257  */
 258 static int gasket_map_pci_bar(struct gasket_dev *gasket_dev, int bar_num)
 259 {
 260         struct gasket_internal_desc *internal_desc = gasket_dev->internal_desc;
 261         const struct gasket_driver_desc *driver_desc =
 262                 internal_desc->driver_desc;
 263         ulong desc_bytes = driver_desc->bar_descriptions[bar_num].size;
 264         int ret;
 265
 266         if (desc_bytes == 0)
 267                 return 0;
 268
 269         if (driver_desc->bar_descriptions[bar_num].type != PCI_BAR) {
 270                 /* not PCI: skip this entry */
 271                 return 0;
 272         }
 273         /*
 274          * pci_resource_start and pci_resource_len return a "resource_size_t",
 275          * which is safely castable to ulong (which itself is the arg to
 276          * request_mem_region).
 277          */
 278         gasket_dev->bar_data[bar_num].phys_base =
 279                 (ulong)pci_resource_start(gasket_dev->pci_dev, bar_num);
 280         if (!gasket_dev->bar_data[bar_num].phys_base) {
 281                 dev_err(gasket_dev->dev, "Cannot get BAR%u base address\n",
 282                         bar_num);
 283                 return -EINVAL;
 284         }
 285
 286         gasket_dev->bar_data[bar_num].length_bytes =
 287                 (ulong)pci_resource_len(gasket_dev->pci_dev, bar_num);
 288         if (gasket_dev->bar_data[bar_num].length_bytes < desc_bytes) {
 289                 dev_err(gasket_dev->dev,
 290                         "PCI BAR %u space is too small: %lu; expected >= %lu\n",
 291                         bar_num, gasket_dev->bar_data[bar_num].length_bytes,
 292                         desc_bytes);
 293                 return -ENOMEM;
 294         }
 295
 296         if (!request_mem_region(gasket_dev->bar_data[bar_num].phys_base,
 297                                 gasket_dev->bar_data[bar_num].length_bytes,
 298                                 gasket_dev->dev_info.name)) {
 299                 dev_err(gasket_dev->dev,
 300                         "Cannot get BAR %d memory region %p\n",
 301                         bar_num, &gasket_dev->pci_dev->resource[bar_num]);
 302                 return -EINVAL;
 303         }
 304
 305         gasket_dev->bar_data[bar_num].virt_base =
 306                 ioremap_nocache(gasket_dev->bar_data[bar_num].phys_base,
 307                                 gasket_dev->bar_data[bar_num].length_bytes);
 308         if (!gasket_dev->bar_data[bar_num].virt_base) {
 309                 dev_err(gasket_dev->dev,
 310                         "Cannot remap BAR %d memory region %p\n",
 311                         bar_num, &gasket_dev->pci_dev->resource[bar_num]);
 312                 ret = -ENOMEM;
 313                 goto fail;
 314         }
 315
 316         dma_set_mask(&gasket_dev->pci_dev->dev, DMA_BIT_MASK(64));
 317         dma_set_coherent_mask(&gasket_dev->pci_dev->dev, DMA_BIT_MASK(64));
 318
 319         return 0;
 320
 321 fail:
 322         iounmap(gasket_dev->bar_data[bar_num].virt_base);
 323         release_mem_region(gasket_dev->bar_data[bar_num].phys_base,
 324                            gasket_dev->bar_data[bar_num].length_bytes);
 325         return ret;
 326 }
 327
 328 /*
 329  * Releases PCI BAR mapping.
 330  *
 331  * A zero-sized or not-mapped BAR will not be unmapped, but is not an error.
 332  */
 333 static void gasket_unmap_pci_bar(struct gasket_dev *dev, int bar_num)
 334 {
 335         ulong base, bytes;
 336         struct gasket_internal_desc *internal_desc = dev->internal_desc;
 337         const struct gasket_driver_desc *driver_desc =
 338                 internal_desc->driver_desc;
 339
 340         if (driver_desc->bar_descriptions[bar_num].size == 0 ||
 341             !dev->bar_data[bar_num].virt_base)
 342                 return;
 343
 344         if (driver_desc->bar_descriptions[bar_num].type != PCI_BAR)
 345                 return;
 346
 347         iounmap(dev->bar_data[bar_num].virt_base);
 348         dev->bar_data[bar_num].virt_base = NULL;
 349
 350         base = pci_resource_start(dev->pci_dev, bar_num);
 351         if (!base) {
 352                 dev_err(dev->dev, "cannot get PCI BAR%u base address\n",
 353                         bar_num);
 354                 return;
 355         }
 356
 357         bytes = pci_resource_len(dev->pci_dev, bar_num);
 358         release_mem_region(base, bytes);
 359 }
 360
 361 /*
 362  * Setup PCI memory mapping for the specified device.
 363  *
 364  * Reads the BAR registers and sets up pointers to the device's memory mapped
 365  * IO space.
 366  *
 367  * Returns 0 on success and a negative value otherwise.
 368  */
 369 static int gasket_setup_pci(struct pci_dev *pci_dev,
 370                             struct gasket_dev *gasket_dev)
 371 {
 372         int i, mapped_bars, ret;
 373
 374         for (i = 0; i < GASKET_NUM_BARS; i++) {
 375                 ret = gasket_map_pci_bar(gasket_dev, i);
 376                 if (ret) {
 377                         mapped_bars = i;
 378                         goto fail;
 379                 }
 380         }
 381
 382         return 0;
 383
 384 fail:
 385         for (i = 0; i < mapped_bars; i++)
 386                 gasket_unmap_pci_bar(gasket_dev, i);
 387
 388         return -ENOMEM;
 389 }
 390
 391 /* Unmaps memory for the specified device. */
 392 static void gasket_cleanup_pci(struct gasket_dev *gasket_dev)
 393 {
 394         int i;
 395
 396         for (i = 0; i < GASKET_NUM_BARS; i++)
 397                 gasket_unmap_pci_bar(gasket_dev, i);
 398 }
 399
 400 /* Determine the health of the Gasket device. */
 401 static int gasket_get_hw_status(struct gasket_dev *gasket_dev)
 402 {
 403         int status;
 404         int i;
 405         const struct gasket_driver_desc *driver_desc =
 406                 gasket_dev->internal_desc->driver_desc;
 407
 408         status = gasket_check_and_invoke_callback_nolock(gasket_dev,
 409                                                          driver_desc->device_status_cb);
 410         if (status != GASKET_STATUS_ALIVE) {
 411                 dev_dbg(gasket_dev->dev, "Hardware reported status %d.\n",
 412                         status);
 413                 return status;
 414         }
 415
 416         status = gasket_interrupt_system_status(gasket_dev);
 417         if (status != GASKET_STATUS_ALIVE) {
 418                 dev_dbg(gasket_dev->dev,
 419                         "Interrupt system reported status %d.\n", status);
 420                 return status;
 421         }
 422
 423         for (i = 0; i < driver_desc->num_page_tables; ++i) {
 424                 status = gasket_page_table_system_status(gasket_dev->page_table[i]);
 425                 if (status != GASKET_STATUS_ALIVE) {
 426                         dev_dbg(gasket_dev->dev,
 427                                 "Page table %d reported status %d.\n",
 428                                 i, status);
 429                         return status;
 430                 }
 431         }
 432
 433         return GASKET_STATUS_ALIVE;
 434 }
 435
 436 static ssize_t
 437 gasket_write_mappable_regions(char *buf,
 438                               const struct gasket_driver_desc *driver_desc,
 439                               int bar_index)
 440 {
 441         int i;
 442         ssize_t written;
 443         ssize_t total_written = 0;
 444         ulong min_addr, max_addr;
 445         struct gasket_bar_desc bar_desc =
 446                 driver_desc->bar_descriptions[bar_index];
 447
 448         if (bar_desc.permissions == GASKET_NOMAP)
 449                 return 0;
 450         for (i = 0;
 451              i < bar_desc.num_mappable_regions && total_written < PAGE_SIZE;
 452              i++) {
 453                 min_addr = bar_desc.mappable_regions[i].start -
 454                            driver_desc->legacy_mmap_address_offset;
 455                 max_addr = bar_desc.mappable_regions[i].start -
 456                            driver_desc->legacy_mmap_address_offset +
 457                            bar_desc.mappable_regions[i].length_bytes;
 458                 written = scnprintf(buf, PAGE_SIZE - total_written,
 459                                     "0x%08lx-0x%08lx\n", min_addr, max_addr);
 460                 total_written += written;
 461                 buf += written;
 462         }
 463         return total_written;
 464 }
 465
 466 static ssize_t gasket_sysfs_data_show(struct device *device,
 467                                       struct device_attribute *attr, char *buf)
 468 {
 469         int i, ret = 0;
 470         ssize_t current_written = 0;
 471         const struct gasket_driver_desc *driver_desc;
 472         struct gasket_dev *gasket_dev;
 473         struct gasket_sysfs_attribute *gasket_attr;
 474         const struct gasket_bar_desc *bar_desc;
 475         enum gasket_sysfs_attribute_type sysfs_type;
 476
 477         gasket_dev = gasket_sysfs_get_device_data(device);
 478         if (!gasket_dev) {
 479                 dev_err(device, "No sysfs mapping found for device\n");
 480                 return 0;
 481         }
 482
 483         gasket_attr = gasket_sysfs_get_attr(device, attr);
 484         if (!gasket_attr) {
 485                 dev_err(device, "No sysfs attr found for device\n");
 486                 gasket_sysfs_put_device_data(device, gasket_dev);
 487                 return 0;
 488         }
 489
 490         driver_desc = gasket_dev->internal_desc->driver_desc;
 491
 492         sysfs_type =
 493                 (enum gasket_sysfs_attribute_type)gasket_attr->data.attr_type;
 494         switch (sysfs_type) {
 495         case ATTR_BAR_OFFSETS:
 496                 for (i = 0; i < GASKET_NUM_BARS; i++) {
 497                         bar_desc = &driver_desc->bar_descriptions[i];
 498                         if (bar_desc->size == 0)
 499                                 continue;
 500                         current_written =
 501                                 snprintf(buf, PAGE_SIZE - ret, "%d: 0x%lx\n", i,
 502                                          (ulong)bar_desc->base);
 503                         buf += current_written;
 504                         ret += current_written;
 505                 }
 506                 break;
 507         case ATTR_BAR_SIZES:
 508                 for (i = 0; i < GASKET_NUM_BARS; i++) {
 509                         bar_desc = &driver_desc->bar_descriptions[i];
 510                         if (bar_desc->size == 0)
 511                                 continue;
 512                         current_written =
 513                                 snprintf(buf, PAGE_SIZE - ret, "%d: 0x%lx\n", i,
 514                                          (ulong)bar_desc->size);
 515                         buf += current_written;
 516                         ret += current_written;
 517                 }
 518                 break;
 519         case ATTR_DRIVER_VERSION:
 520                 ret = snprintf(buf, PAGE_SIZE, "%s\n",
 521                                gasket_dev->internal_desc->driver_desc->driver_version);
 522                 break;
 523         case ATTR_FRAMEWORK_VERSION:
 524                 ret = snprintf(buf, PAGE_SIZE, "%s\n",
 525                                GASKET_FRAMEWORK_VERSION);
 526                 break;
 527         case ATTR_DEVICE_TYPE:
 528                 ret = snprintf(buf, PAGE_SIZE, "%s\n",
 529                                gasket_dev->internal_desc->driver_desc->name);
 530                 break;
 531         case ATTR_HARDWARE_REVISION:
 532                 ret = snprintf(buf, PAGE_SIZE, "%d\n",
 533                                gasket_dev->hardware_revision);
 534                 break;
 535         case ATTR_PCI_ADDRESS:
 536                 ret = snprintf(buf, PAGE_SIZE, "%s\n", gasket_dev->kobj_name);
 537                 break;
 538         case ATTR_STATUS:
 539                 ret = snprintf(buf, PAGE_SIZE, "%s\n",
 540                                gasket_num_name_lookup(gasket_dev->status,
 541                                                       gasket_status_name_table));
 542                 break;
 543         case ATTR_IS_DEVICE_OWNED:
 544                 ret = snprintf(buf, PAGE_SIZE, "%d\n",
 545                                gasket_dev->dev_info.ownership.is_owned);
 546                 break;
 547         case ATTR_DEVICE_OWNER:
 548                 ret = snprintf(buf, PAGE_SIZE, "%d\n",
 549                                gasket_dev->dev_info.ownership.owner);
 550                 break;
 551         case ATTR_WRITE_OPEN_COUNT:
 552                 ret = snprintf(buf, PAGE_SIZE, "%d\n",
 553                                gasket_dev->dev_info.ownership.write_open_count);
 554                 break;
 555         case ATTR_RESET_COUNT:
 556                 ret = snprintf(buf, PAGE_SIZE, "%d\n", gasket_dev->reset_count);
 557                 break;
 558         case ATTR_USER_MEM_RANGES:
 559                 for (i = 0; i < GASKET_NUM_BARS; ++i) {
 560                         current_written =
 561                                 gasket_write_mappable_regions(buf, driver_desc,
 562                                                               i);
 563                         buf += current_written;
 564                         ret += current_written;
 565                 }
 566                 break;
 567         default:
 568                 dev_dbg(gasket_dev->dev, "Unknown attribute: %s\n",
 569                         attr->attr.name);
 570                 ret = 0;
 571                 break;
 572         }
 573
 574         gasket_sysfs_put_attr(device, gasket_attr);
 575         gasket_sysfs_put_device_data(device, gasket_dev);
 576         return ret;
 577 }
 578
 579 /* These attributes apply to all Gasket driver instances. */
 580 static const struct gasket_sysfs_attribute gasket_sysfs_generic_attrs[] = {
 581         GASKET_SYSFS_RO(bar_offsets, gasket_sysfs_data_show, ATTR_BAR_OFFSETS),
 582         GASKET_SYSFS_RO(bar_sizes, gasket_sysfs_data_show, ATTR_BAR_SIZES),
 583         GASKET_SYSFS_RO(driver_version, gasket_sysfs_data_show,
 584                         ATTR_DRIVER_VERSION),
 585         GASKET_SYSFS_RO(framework_version, gasket_sysfs_data_show,
 586                         ATTR_FRAMEWORK_VERSION),
 587         GASKET_SYSFS_RO(device_type, gasket_sysfs_data_show, ATTR_DEVICE_TYPE),
 588         GASKET_SYSFS_RO(revision, gasket_sysfs_data_show,
 589                         ATTR_HARDWARE_REVISION),
 590         GASKET_SYSFS_RO(pci_address, gasket_sysfs_data_show, ATTR_PCI_ADDRESS),
 591         GASKET_SYSFS_RO(status, gasket_sysfs_data_show, ATTR_STATUS),
 592         GASKET_SYSFS_RO(is_device_owned, gasket_sysfs_data_show,
 593                         ATTR_IS_DEVICE_OWNED),
 594         GASKET_SYSFS_RO(device_owner, gasket_sysfs_data_show,
 595                         ATTR_DEVICE_OWNER),
 596         GASKET_SYSFS_RO(write_open_count, gasket_sysfs_data_show,
 597                         ATTR_WRITE_OPEN_COUNT),
 598         GASKET_SYSFS_RO(reset_count, gasket_sysfs_data_show, ATTR_RESET_COUNT),
 599         GASKET_SYSFS_RO(user_mem_ranges, gasket_sysfs_data_show,
 600                         ATTR_USER_MEM_RANGES),
 601         GASKET_END_OF_ATTR_ARRAY
 602 };
 603
 604 /* Add a char device and related info. */
 605 static int gasket_add_cdev(struct gasket_cdev_info *dev_info,
 606                            const struct file_operations *file_ops,
 607                            struct module *owner)
 608 {
 609         int ret;
 610
 611         cdev_init(&dev_info->cdev, file_ops);
 612         dev_info->cdev.owner = owner;
 613         ret = cdev_add(&dev_info->cdev, dev_info->devt, 1);
 614         if (ret) {
 615                 dev_err(dev_info->gasket_dev_ptr->dev,
 616                         "cannot add char device [ret=%d]\n", ret);
 617                 return ret;
 618         }
 619         dev_info->cdev_added = 1;
 620
 621         return 0;
 622 }
 623
 624 /* Disable device operations. */
 625 void gasket_disable_device(struct gasket_dev *gasket_dev)
 626 {
 627         const struct gasket_driver_desc *driver_desc =
 628                 gasket_dev->internal_desc->driver_desc;
 629         int i;
 630
 631         /* Only delete the device if it has been successfully added. */
 632         if (gasket_dev->dev_info.cdev_added)
 633                 cdev_del(&gasket_dev->dev_info.cdev);
 634
 635         gasket_dev->status = GASKET_STATUS_DEAD;
 636
 637         gasket_interrupt_cleanup(gasket_dev);
 638
 639         for (i = 0; i < driver_desc->num_page_tables; ++i) {
 640                 if (gasket_dev->page_table[i]) {
 641                         gasket_page_table_reset(gasket_dev->page_table[i]);
 642                         gasket_page_table_cleanup(gasket_dev->page_table[i]);
 643                 }
 644         }
 645 }
 646 EXPORT_SYMBOL(gasket_disable_device);
 647
 648 /*
 649  * Registered driver descriptor lookup for PCI devices.
 650  *
 651  * Precondition: Called with g_mutex held (to avoid a race on return).
 652  * Returns NULL if no matching device was found.
 653  */
 654 static struct gasket_internal_desc *
 655 lookup_pci_internal_desc(struct pci_dev *pci_dev)
 656 {
 657         int i;
 658
 659         __must_hold(&g_mutex);
 660         for (i = 0; i < GASKET_FRAMEWORK_DESC_MAX; i++) {
 661                 if (g_descs[i].driver_desc &&
 662                     g_descs[i].driver_desc->pci_id_table &&
 663                     pci_match_id(g_descs[i].driver_desc->pci_id_table, pci_dev))
 664                         return &g_descs[i];
 665         }
 666
 667         return NULL;
 668 }
 669
 670 /*
 671  * Verifies that the user has permissions to perform the requested mapping and
 672  * that the provided descriptor/range is of adequate size to hold the range to
 673  * be mapped.
 674  */
 675 static bool gasket_mmap_has_permissions(struct gasket_dev *gasket_dev,
 676                                         struct vm_area_struct *vma,
 677                                         int bar_permissions)
 678 {
 679         int requested_permissions;
 680         /* Always allow sysadmin to access. */
 681         if (capable(CAP_SYS_ADMIN))
 682                 return true;
 683
 684         /* Never allow non-sysadmins to access to a dead device. */
 685         if (gasket_dev->status != GASKET_STATUS_ALIVE) {
 686                 dev_dbg(gasket_dev->dev, "Device is dead.\n");
 687                 return false;
 688         }
 689
 690         /* Make sure that no wrong flags are set. */
 691         requested_permissions =
 692                 (vma->vm_flags & (VM_WRITE | VM_READ | VM_EXEC));
 693         if (requested_permissions & ~(bar_permissions)) {
 694                 dev_dbg(gasket_dev->dev,
 695                         "Attempting to map a region with requested permissions "
 696                         "0x%x, but region has permissions 0x%x.\n",
 697                         requested_permissions, bar_permissions);
 698                 return false;
 699         }
 700
 701         /* Do not allow a non-owner to write. */
 702         if ((vma->vm_flags & VM_WRITE) &&
 703             !gasket_owned_by_current_tgid(&gasket_dev->dev_info)) {
 704                 dev_dbg(gasket_dev->dev,
 705                         "Attempting to mmap a region for write without owning device.\n");
 706                 return false;
 707         }
 708
 709         return true;
 710 }
 711
 712 /*
 713  * Verifies that the input address is within the region allocated to coherent
 714  * buffer.
 715  */
 716 static bool
 717 gasket_is_coherent_region(const struct gasket_driver_desc *driver_desc,
 718                           ulong address)
 719 {
 720         struct gasket_coherent_buffer_desc coh_buff_desc =
 721                 driver_desc->coherent_buffer_description;
 722
 723         if (coh_buff_desc.permissions != GASKET_NOMAP) {
 724                 if ((address >= coh_buff_desc.base) &&
 725                     (address < coh_buff_desc.base + coh_buff_desc.size)) {
 726                         return true;
 727                 }
 728         }
 729         return false;
 730 }
 731
 732 static int gasket_get_bar_index(const struct gasket_dev *gasket_dev,
 733                                 ulong phys_addr)
 734 {
 735         int i;
 736         const struct gasket_driver_desc *driver_desc;
 737
 738         driver_desc = gasket_dev->internal_desc->driver_desc;
 739         for (i = 0; i < GASKET_NUM_BARS; ++i) {
 740                 struct gasket_bar_desc bar_desc =
 741                         driver_desc->bar_descriptions[i];
 742
 743                 if (bar_desc.permissions != GASKET_NOMAP) {
 744                         if (phys_addr >= bar_desc.base &&
 745                             phys_addr < (bar_desc.base + bar_desc.size)) {
 746                                 return i;
 747                         }
 748                 }
 749         }
 750         /* If we haven't found the address by now, it is invalid. */
 751         return -EINVAL;
 752 }
 753
 754 /*
 755  * Sets the actual bounds to map, given the device's mappable region.
 756  *
 757  * Given the device's mappable region, along with the user-requested mapping
 758  * start offset and length of the user region, determine how much of this
 759  * mappable region can be mapped into the user's region (start/end offsets),
 760  * and the physical offset (phys_offset) into the BAR where the mapping should
 761  * begin (either the VMA's or region lower bound).
 762  *
 763  * In other words, this calculates the overlap between the VMA
 764  * (bar_offset, requested_length) and the given gasket_mappable_region.
 765  *
 766  * Returns true if there's anything to map, and false otherwise.
 767  */
 768 static bool
 769 gasket_mm_get_mapping_addrs(const struct gasket_mappable_region *region,
 770                             ulong bar_offset, ulong requested_length,
 771                             struct gasket_mappable_region *mappable_region,
 772                             ulong *virt_offset)
 773 {
 774         ulong range_start = region->start;
 775         ulong range_length = region->length_bytes;
 776         ulong range_end = range_start + range_length;
 777
 778         *virt_offset = 0;
 779         if (bar_offset + requested_length < range_start) {
 780                 /*
 781                  * If the requested region is completely below the range,
 782                  * there is nothing to map.
 783                  */
 784                 return false;
 785         } else if (bar_offset <= range_start) {
 786                 /* If the bar offset is below this range's start
 787                  * but the requested length continues into it:
 788                  * 1) Only map starting from the beginning of this
 789                  *      range's phys. offset, so we don't map unmappable
 790                  *      memory.
 791                  * 2) The length of the virtual memory to not map is the
 792                  *      delta between the bar offset and the
 793                  *      mappable start (and since the mappable start is
 794                  *      bigger, start - req.)
 795                  * 3) The map length is the minimum of the mappable
 796                  *      requested length (requested_length - virt_offset)
 797                  *      and the actual mappable length of the range.
 798                  */
 799                 mappable_region->start = range_start;
 800                 *virt_offset = range_start - bar_offset;
 801                 mappable_region->length_bytes =
 802                         min(requested_length - *virt_offset, range_length);
 803                 return true;
 804         } else if (bar_offset > range_start &&
 805                    bar_offset < range_end) {
 806                 /*
 807                  * If the bar offset is within this range:
 808                  * 1) Map starting from the bar offset.
 809                  * 2) Because there is no forbidden memory between the
 810                  *      bar offset and the range start,
 811                  *      virt_offset is 0.
 812                  * 3) The map length is the minimum of the requested
 813                  *      length and the remaining length in the buffer
 814                  *      (range_end - bar_offset)
 815                  */
 816                 mappable_region->start = bar_offset;
 817                 *virt_offset = 0;
 818                 mappable_region->length_bytes =
 819                         min(requested_length, range_end - bar_offset);
 820                 return true;
 821         }
 822
 823         /*
 824          * If the requested [start] offset is above range_end,
 825          * there's nothing to map.
 826          */
 827         return false;
 828 }
 829
 830 /*
 831  * Calculates the offset where the VMA range begins in its containing BAR.
 832  * The offset is written into bar_offset on success.
 833  * Returns zero on success, anything else on error.
 834  */
 835 static int gasket_mm_vma_bar_offset(const struct gasket_dev *gasket_dev,
 836                                     const struct vm_area_struct *vma,
 837                                     ulong *bar_offset)
 838 {
 839         ulong raw_offset;
 840         int bar_index;
 841         const struct gasket_driver_desc *driver_desc =
 842                 gasket_dev->internal_desc->driver_desc;
 843
 844         raw_offset = (vma->vm_pgoff << PAGE_SHIFT) +
 845                 driver_desc->legacy_mmap_address_offset;
 846         bar_index = gasket_get_bar_index(gasket_dev, raw_offset);
 847         if (bar_index < 0) {
 848                 dev_err(gasket_dev->dev,
 849                         "Unable to find matching bar for address 0x%lx\n",
 850                         raw_offset);
 851                 trace_gasket_mmap_exit(bar_index);
 852                 return bar_index;
 853         }
 854         *bar_offset =
 855                 raw_offset - driver_desc->bar_descriptions[bar_index].base;
 856
 857         return 0;
 858 }
 859
 860 int gasket_mm_unmap_region(const struct gasket_dev *gasket_dev,
 861                            struct vm_area_struct *vma,
 862                            const struct gasket_mappable_region *map_region)
 863 {
 864         ulong bar_offset;
 865         ulong virt_offset;
 866         struct gasket_mappable_region mappable_region;
 867         int ret;
 868
 869         if (map_region->length_bytes == 0)
 870                 return 0;
 871
 872         ret = gasket_mm_vma_bar_offset(gasket_dev, vma, &bar_offset);
 873         if (ret)
 874                 return ret;
 875
 876         if (!gasket_mm_get_mapping_addrs(map_region, bar_offset,
 877                                          vma->vm_end - vma->vm_start,
 878                                          &mappable_region, &virt_offset))
 879                 return 1;
 880
 881         /*
 882          * The length passed to zap_vma_ptes MUST BE A MULTIPLE OF
 883          * PAGE_SIZE! Trust me. I have the scars.
 884          *
 885          * Next multiple of y: ceil_div(x, y) * y
 886          */
 887         zap_vma_ptes(vma, vma->vm_start + virt_offset,
 888                      DIV_ROUND_UP(mappable_region.length_bytes, PAGE_SIZE) *
 889                      PAGE_SIZE);
 890         return 0;
 891 }
 892 EXPORT_SYMBOL(gasket_mm_unmap_region);
 893
 894 /* Maps a virtual address + range to a physical offset of a BAR. */
 895 static enum do_map_region_status
 896 do_map_region(const struct gasket_dev *gasket_dev, struct vm_area_struct *vma,
 897               struct gasket_mappable_region *mappable_region)
 898 {
 899         /* Maximum size of a single call to io_remap_pfn_range. */
 900         /* I pulled this number out of thin air. */
 901         const ulong max_chunk_size = 64 * 1024 * 1024;
 902         ulong chunk_size, mapped_bytes = 0;
 903
 904         const struct gasket_driver_desc *driver_desc =
 905                 gasket_dev->internal_desc->driver_desc;
 906
 907         ulong bar_offset, virt_offset;
 908         struct gasket_mappable_region region_to_map;
 909         ulong phys_offset, map_length;
 910         ulong virt_base, phys_base;
 911         int bar_index, ret;
 912
 913         ret = gasket_mm_vma_bar_offset(gasket_dev, vma, &bar_offset);
 914         if (ret)
 915                 return DO_MAP_REGION_INVALID;
 916
 917         if (!gasket_mm_get_mapping_addrs(mappable_region, bar_offset,
 918                                          vma->vm_end - vma->vm_start,
 919                                          &region_to_map, &virt_offset))
 920                 return DO_MAP_REGION_INVALID;
 921         phys_offset = region_to_map.start;
 922         map_length = region_to_map.length_bytes;
 923
 924         virt_base = vma->vm_start + virt_offset;
 925         bar_index =
 926                 gasket_get_bar_index(gasket_dev,
 927                                      (vma->vm_pgoff << PAGE_SHIFT) +
 928                                      driver_desc->legacy_mmap_address_offset);
 929         phys_base = gasket_dev->bar_data[bar_index].phys_base + phys_offset;
 930         while (mapped_bytes < map_length) {
 931                 /*
 932                  * io_remap_pfn_range can take a while, so we chunk its
 933                  * calls and call cond_resched between each.
 934                  */
 935                 chunk_size = min(max_chunk_size, map_length - mapped_bytes);
 936
 937                 cond_resched();
 938                 ret = io_remap_pfn_range(vma, virt_base + mapped_bytes,
 939                                          (phys_base + mapped_bytes) >>
 940                                          PAGE_SHIFT, chunk_size,
 941                                          vma->vm_page_prot);
 942                 if (ret) {
 943                         dev_err(gasket_dev->dev,
 944                                 "Error remapping PFN range.\n");
 945                         goto fail;
 946                 }
 947                 mapped_bytes += chunk_size;
 948         }
 949
 950         return DO_MAP_REGION_SUCCESS;
 951
 952 fail:
 953         /* Unmap the partial chunk we mapped. */
 954         mappable_region->length_bytes = mapped_bytes;
 955         if (gasket_mm_unmap_region(gasket_dev, vma, mappable_region))
 956                 dev_err(gasket_dev->dev,
 957                         "Error unmapping partial region 0x%lx (0x%lx bytes)\n",
 958                         (ulong)virt_offset,
 959                         (ulong)mapped_bytes);
 960
 961         return DO_MAP_REGION_FAILURE;
 962 }
 963
 964 /* Map a region of coherent memory. */
 965 static int gasket_mmap_coherent(struct gasket_dev *gasket_dev,
 966                                 struct vm_area_struct *vma)
 967 {
 968         const struct gasket_driver_desc *driver_desc =
 969                 gasket_dev->internal_desc->driver_desc;
 970         const ulong requested_length = vma->vm_end - vma->vm_start;
 971         int ret;
 972         ulong permissions;
 973
 974         if (requested_length == 0 || requested_length >
 975             gasket_dev->coherent_buffer.length_bytes) {
 976                 trace_gasket_mmap_exit(-EINVAL);
 977                 return -EINVAL;
 978         }
 979
 980         permissions = driver_desc->coherent_buffer_description.permissions;
 981         if (!gasket_mmap_has_permissions(gasket_dev, vma, permissions)) {
 982                 dev_err(gasket_dev->dev, "Permission checking failed.\n");
 983                 trace_gasket_mmap_exit(-EPERM);
 984                 return -EPERM;
 985         }
 986
 987         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 988
 989         ret = remap_pfn_range(vma, vma->vm_start,
 990                               (gasket_dev->coherent_buffer.phys_base) >>
 991                               PAGE_SHIFT, requested_length, vma->vm_page_prot);
 992         if (ret) {
 993                 dev_err(gasket_dev->dev, "Error remapping PFN range err=%d.\n",
 994                         ret);
 995                 trace_gasket_mmap_exit(ret);
 996                 return ret;
 997         }
 998
 999         /* Record the user virtual to dma_address mapping that was
1000          * created by the kernel.
1001          */
1002         gasket_set_user_virt(gasket_dev, requested_length,
1003                              gasket_dev->coherent_buffer.phys_base,
1004                              vma->vm_start);
1005         return 0;
1006 }
1007
1008 /* Map a device's BARs into user space. */
1009 static int gasket_mmap(struct file *filp, struct vm_area_struct *vma)
1010 {
1011         int i, ret;
1012         int bar_index;
1013         int has_mapped_anything = 0;
1014         ulong permissions;
1015         ulong raw_offset, vma_size;
1016         bool is_coherent_region;
1017         const struct gasket_driver_desc *driver_desc;
1018         struct gasket_dev *gasket_dev = (struct gasket_dev *)filp->private_data;
1019         const struct gasket_bar_desc *bar_desc;
1020         struct gasket_mappable_region *map_regions = NULL;
1021         int num_map_regions = 0;
1022         enum do_map_region_status map_status;
1023
1024         driver_desc = gasket_dev->internal_desc->driver_desc;
1025
1026         if (vma->vm_start & ~PAGE_MASK) {
1027                 dev_err(gasket_dev->dev,
1028                         "Base address not page-aligned: 0x%lx\n",
1029                         vma->vm_start);
1030                 trace_gasket_mmap_exit(-EINVAL);
1031                 return -EINVAL;
1032         }
1033
1034         /* Calculate the offset of this range into physical mem. */
1035         raw_offset = (vma->vm_pgoff << PAGE_SHIFT) +
1036                 driver_desc->legacy_mmap_address_offset;
1037         vma_size = vma->vm_end - vma->vm_start;
1038         trace_gasket_mmap_entry(gasket_dev->dev_info.name, raw_offset,
1039                                 vma_size);
1040
1041         /*
1042          * Check if the raw offset is within a bar region. If not, check if it
1043          * is a coherent region.
1044          */
1045         bar_index = gasket_get_bar_index(gasket_dev, raw_offset);
1046         is_coherent_region = gasket_is_coherent_region(driver_desc, raw_offset);
1047         if (bar_index < 0 && !is_coherent_region) {
1048                 dev_err(gasket_dev->dev,
1049                         "Unable to find matching bar for address 0x%lx\n",
1050                         raw_offset);
1051                 trace_gasket_mmap_exit(bar_index);
1052                 return bar_index;
1053         }
1054         if (bar_index > 0 && is_coherent_region) {
1055                 dev_err(gasket_dev->dev,
1056                         "double matching bar and coherent buffers for address 0x%lx\n",
1057                         raw_offset);
1058                 trace_gasket_mmap_exit(bar_index);
1059                 return -EINVAL;
1060         }
1061
1062         vma->vm_private_data = gasket_dev;
1063
1064         if (is_coherent_region)
1065                 return gasket_mmap_coherent(gasket_dev, vma);
1066
1067         /* Everything in the rest of this function is for normal BAR mapping. */
1068
1069         /*
1070          * Subtract the base of the bar from the raw offset to get the
1071          * memory location within the bar to map.
1072          */
1073         bar_desc = &driver_desc->bar_descriptions[bar_index];
1074         permissions = bar_desc->permissions;
1075         if (!gasket_mmap_has_permissions(gasket_dev, vma, permissions)) {
1076                 dev_err(gasket_dev->dev, "Permission checking failed.\n");
1077                 trace_gasket_mmap_exit(-EPERM);
1078                 return -EPERM;
1079         }
1080
1081         if (driver_desc->get_mappable_regions_cb) {
1082                 ret = driver_desc->get_mappable_regions_cb(gasket_dev,
1083                                                            bar_index,
1084                                                            &map_regions,
1085                                                            &num_map_regions);
1086                 if (ret)
1087                         return ret;
1088         } else {
1089                 if (!gasket_mmap_has_permissions(gasket_dev, vma,
1090                                                  bar_desc->permissions)) {
1091                         dev_err(gasket_dev->dev,
1092                                 "Permission checking failed.\n");
1093                         trace_gasket_mmap_exit(-EPERM);
1094                         return -EPERM;
1095                 }
1096                 num_map_regions = bar_desc->num_mappable_regions;
1097                 map_regions = kcalloc(num_map_regions,
1098                                       sizeof(*bar_desc->mappable_regions),
1099                                       GFP_KERNEL);
1100                 if (map_regions) {
1101                         memcpy(map_regions, bar_desc->mappable_regions,
1102                                num_map_regions *
1103                                         sizeof(*bar_desc->mappable_regions));
1104                 }
1105         }
1106
1107         if (!map_regions || num_map_regions == 0) {
1108                 dev_err(gasket_dev->dev, "No mappable regions returned!\n");
1109                 return -EINVAL;
1110         }
1111
1112         /* Marks the VMA's pages as uncacheable. */
1113         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
1114         for (i = 0; i < num_map_regions; i++) {
1115                 map_status = do_map_region(gasket_dev, vma, &map_regions[i]);
1116                 /* Try the next region if this one was not mappable. */
1117                 if (map_status == DO_MAP_REGION_INVALID)
1118                         continue;
1119                 if (map_status == DO_MAP_REGION_FAILURE) {
1120                         ret = -ENOMEM;
1121                         goto fail;
1122                 }
1123
1124                 has_mapped_anything = 1;
1125         }
1126
1127         kfree(map_regions);
1128
1129         /* If we could not map any memory, the request was invalid. */
1130         if (!has_mapped_anything) {
1131                 dev_err(gasket_dev->dev,
1132                         "Map request did not contain a valid region.\n");
1133                 trace_gasket_mmap_exit(-EINVAL);
1134                 return -EINVAL;
1135         }
1136
1137         trace_gasket_mmap_exit(0);
1138         return 0;
1139
1140 fail:
1141         /* Need to unmap any mapped ranges. */
1142         num_map_regions = i;
1143         for (i = 0; i < num_map_regions; i++)
1144                 if (gasket_mm_unmap_region(gasket_dev, vma,
1145                                            &bar_desc->mappable_regions[i]))
1146                         dev_err(gasket_dev->dev, "Error unmapping range %d.\n",
1147                                 i);
1148         kfree(map_regions);
1149
1150         return ret;
1151 }
1152
1153 /*
1154  * Open the char device file.
1155  *
1156  * If the open is for writing, and the device is not owned, this process becomes
1157  * the owner.  If the open is for writing and the device is already owned by
1158  * some other process, it is an error.  If this process is the owner, increment
1159  * the open count.
1160  *
1161  * Returns 0 if successful, a negative error number otherwise.
1162  */
1163 static int gasket_open(struct inode *inode, struct file *filp)
1164 {
1165         int ret;
1166         struct gasket_dev *gasket_dev;
1167         const struct gasket_driver_desc *driver_desc;
1168         struct gasket_ownership *ownership;
1169         char task_name[TASK_COMM_LEN];
1170         struct gasket_cdev_info *dev_info =
1171             container_of(inode->i_cdev, struct gasket_cdev_info, cdev);
1172         struct pid_namespace *pid_ns = task_active_pid_ns(current);
1173         bool is_root = ns_capable(pid_ns->user_ns, CAP_SYS_ADMIN);
1174
1175         gasket_dev = dev_info->gasket_dev_ptr;
1176         driver_desc = gasket_dev->internal_desc->driver_desc;
1177         ownership = &dev_info->ownership;
1178         get_task_comm(task_name, current);
1179         filp->private_data = gasket_dev;
1180         inode->i_size = 0;
1181
1182         dev_dbg(gasket_dev->dev,
1183                 "Attempting to open with tgid %u (%s) (f_mode: 0%03o, "
1184                 "fmode_write: %d is_root: %u)\n",
1185                 current->tgid, task_name, filp->f_mode,
1186                 (filp->f_mode & FMODE_WRITE), is_root);
1187
1188         /* Always allow non-writing accesses. */
1189         if (!(filp->f_mode & FMODE_WRITE)) {
1190                 dev_dbg(gasket_dev->dev, "Allowing read-only opening.\n");
1191                 return 0;
1192         }
1193
1194         mutex_lock(&gasket_dev->mutex);
1195
1196         dev_dbg(gasket_dev->dev,
1197                 "Current owner open count (owning tgid %u): %d.\n",
1198                 ownership->owner, ownership->write_open_count);
1199
1200         /* Opening a node owned by another TGID is an error (unless root) */
1201         if (ownership->is_owned && ownership->owner != current->tgid &&
1202             !is_root) {
1203                 dev_err(gasket_dev->dev,
1204                         "Process %u is opening a node held by %u.\n",
1205                         current->tgid, ownership->owner);
1206                 mutex_unlock(&gasket_dev->mutex);
1207                 return -EPERM;
1208         }
1209
1210         /* If the node is not owned, assign it to the current TGID. */
1211         if (!ownership->is_owned) {
1212                 ret = gasket_check_and_invoke_callback_nolock(gasket_dev,
1213                                                               driver_desc->device_open_cb);
1214                 if (ret) {
1215                         dev_err(gasket_dev->dev,
1216                                 "Error in device open cb: %d\n", ret);
1217                         mutex_unlock(&gasket_dev->mutex);
1218                         return ret;
1219                 }
1220                 ownership->is_owned = 1;
1221                 ownership->owner = current->tgid;
1222                 dev_dbg(gasket_dev->dev, "Device owner is now tgid %u\n",
1223                         ownership->owner);
1224         }
1225
1226         ownership->write_open_count++;
1227
1228         dev_dbg(gasket_dev->dev, "New open count (owning tgid %u): %d\n",
1229                 ownership->owner, ownership->write_open_count);
1230
1231         mutex_unlock(&gasket_dev->mutex);
1232         return 0;
1233 }
1234
1235 /*
1236  * Called on a close of the device file.  If this process is the owner,
1237  * decrement the open count.  On last close by the owner, free up buffers and
1238  * eventfd contexts, and release ownership.
1239  *
1240  * Returns 0 if successful, a negative error number otherwise.
1241  */
1242 static int gasket_release(struct inode *inode, struct file *file)
1243 {
1244         int i;
1245         struct gasket_dev *gasket_dev;
1246         struct gasket_ownership *ownership;
1247         const struct gasket_driver_desc *driver_desc;
1248         char task_name[TASK_COMM_LEN];
1249         struct gasket_cdev_info *dev_info =
1250                 container_of(inode->i_cdev, struct gasket_cdev_info, cdev);
1251         struct pid_namespace *pid_ns = task_active_pid_ns(current);
1252         bool is_root = ns_capable(pid_ns->user_ns, CAP_SYS_ADMIN);
1253
1254         gasket_dev = dev_info->gasket_dev_ptr;
1255         driver_desc = gasket_dev->internal_desc->driver_desc;
1256         ownership = &dev_info->ownership;
1257         get_task_comm(task_name, current);
1258         mutex_lock(&gasket_dev->mutex);
1259
1260         dev_dbg(gasket_dev->dev,
1261                 "Releasing device node. Call origin: tgid %u (%s) "
1262                 "(f_mode: 0%03o, fmode_write: %d, is_root: %u)\n",
1263                 current->tgid, task_name, file->f_mode,
1264                 (file->f_mode & FMODE_WRITE), is_root);
1265         dev_dbg(gasket_dev->dev, "Current open count (owning tgid %u): %d\n",
1266                 ownership->owner, ownership->write_open_count);
1267
1268         if (file->f_mode & FMODE_WRITE) {
1269                 ownership->write_open_count--;
1270                 if (ownership->write_open_count == 0) {
1271                         dev_dbg(gasket_dev->dev, "Device is now free\n");
1272                         ownership->is_owned = 0;
1273                         ownership->owner = 0;
1274
1275                         /* Forces chip reset before we unmap the page tables. */
1276                         driver_desc->device_reset_cb(gasket_dev);
1277
1278                         for (i = 0; i < driver_desc->num_page_tables; ++i) {
1279                                 gasket_page_table_unmap_all(gasket_dev->page_table[i]);
1280                                 gasket_page_table_garbage_collect(gasket_dev->page_table[i]);
1281                                 gasket_free_coherent_memory_all(gasket_dev, i);
1282                         }
1283
1284                         /* Closes device, enters power save. */
1285                         gasket_check_and_invoke_callback_nolock(gasket_dev,
1286                                                                 driver_desc->device_close_cb);
1287                 }
1288         }
1289
1290         dev_dbg(gasket_dev->dev, "New open count (owning tgid %u): %d\n",
1291                 ownership->owner, ownership->write_open_count);
1292         mutex_unlock(&gasket_dev->mutex);
1293         return 0;
1294 }
1295
1296 /*
1297  * Gasket ioctl dispatch function.
1298  *
1299  * Check if the ioctl is a generic ioctl. If not, pass the ioctl to the
1300  * ioctl_handler_cb registered in the driver description.
1301  * If the ioctl is a generic ioctl, pass it to gasket_ioctl_handler.
1302  */
1303 static long gasket_ioctl(struct file *filp, uint cmd, ulong arg)
1304 {
1305         struct gasket_dev *gasket_dev;
1306         const struct gasket_driver_desc *driver_desc;
1307         void __user *argp = (void __user *)arg;
1308         char path[256];
1309
1310         gasket_dev = (struct gasket_dev *)filp->private_data;
1311         driver_desc = gasket_dev->internal_desc->driver_desc;
1312         if (!driver_desc) {
1313                 dev_dbg(gasket_dev->dev,
1314                         "Unable to find device descriptor for file %s\n",
1315                         d_path(&filp->f_path, path, 256));
1316                 return -ENODEV;
1317         }
1318
1319         if (!gasket_is_supported_ioctl(cmd)) {
1320                 /*
1321                  * The ioctl handler is not a standard Gasket callback, since
1322                  * it requires different arguments. This means we can't use
1323                  * check_and_invoke_callback.
1324                  */
1325                 if (driver_desc->ioctl_handler_cb)
1326                         return driver_desc->ioctl_handler_cb(filp, cmd, argp);
1327
1328                 dev_dbg(gasket_dev->dev, "Received unknown ioctl 0x%x\n", cmd);
1329                 return -EINVAL;
1330         }
1331
1332         return gasket_handle_ioctl(filp, cmd, argp);
1333 }
1334
1335 /* File operations for all Gasket devices. */
1336 static const struct file_operations gasket_file_ops = {
1337         .owner = THIS_MODULE,
1338         .llseek = no_llseek,
1339         .mmap = gasket_mmap,
1340         .open = gasket_open,
1341         .release = gasket_release,
1342         .unlocked_ioctl = gasket_ioctl,
1343 };
1344
1345 /* Perform final init and marks the device as active. */
1346 int gasket_enable_device(struct gasket_dev *gasket_dev)
1347 {
1348         int tbl_idx;
1349         int ret;
1350         const struct gasket_driver_desc *driver_desc =
1351                 gasket_dev->internal_desc->driver_desc;
1352
1353         ret = gasket_interrupt_init(gasket_dev);
1354         if (ret) {
1355                 dev_err(gasket_dev->dev,
1356                         "Critical failure to allocate interrupts: %d\n", ret);
1357                 gasket_interrupt_cleanup(gasket_dev);
1358                 return ret;
1359         }
1360
1361         for (tbl_idx = 0; tbl_idx < driver_desc->num_page_tables; tbl_idx++) {
1362                 dev_dbg(gasket_dev->dev, "Initializing page table %d.\n",
1363                         tbl_idx);
1364                 ret = gasket_page_table_init(&gasket_dev->page_table[tbl_idx],
1365                                              &gasket_dev->bar_data[driver_desc->page_table_bar_index],
1366                                              &driver_desc->page_table_configs[tbl_idx],
1367                                              gasket_dev->dev,
1368                                              gasket_dev->pci_dev);
1369                 if (ret) {
1370                         dev_err(gasket_dev->dev,
1371                                 "Couldn't init page table %d: %d\n",
1372                                 tbl_idx, ret);
1373                         return ret;
1374                 }
1375                 /*
1376                  * Make sure that the page table is clear and set to simple
1377                  * addresses.
1378                  */
1379                 gasket_page_table_reset(gasket_dev->page_table[tbl_idx]);
1380         }
1381
1382         /*
1383          * hardware_revision_cb returns a positive integer (the rev) if
1384          * successful.)
1385          */
1386         ret = check_and_invoke_callback(gasket_dev,
1387                                         driver_desc->hardware_revision_cb);
1388         if (ret < 0) {
1389                 dev_err(gasket_dev->dev,
1390                         "Error getting hardware revision: %d\n", ret);
1391                 return ret;
1392         }
1393         gasket_dev->hardware_revision = ret;
1394
1395         /* device_status_cb returns a device status, not an error code. */
1396         gasket_dev->status = gasket_get_hw_status(gasket_dev);
1397         if (gasket_dev->status == GASKET_STATUS_DEAD)
1398                 dev_err(gasket_dev->dev, "Device reported as unhealthy.\n");
1399
1400         ret = gasket_add_cdev(&gasket_dev->dev_info, &gasket_file_ops,
1401                               driver_desc->module);
1402         if (ret)
1403                 return ret;
1404
1405         return 0;
1406 }
1407 EXPORT_SYMBOL(gasket_enable_device);
1408
1409 static int __gasket_add_device(struct device *parent_dev,
1410                                struct gasket_internal_desc *internal_desc,
1411                                struct gasket_dev **gasket_devp)
1412 {
1413         int ret;
1414         struct gasket_dev *gasket_dev;
1415         const struct gasket_driver_desc *driver_desc =
1416             internal_desc->driver_desc;
1417
1418         ret = gasket_alloc_dev(internal_desc, parent_dev, &gasket_dev);
1419         if (ret)
1420                 return ret;
1421         if (IS_ERR(gasket_dev->dev_info.device)) {
1422                 dev_err(parent_dev, "Cannot create %s device %s [ret = %ld]\n",
1423                         driver_desc->name, gasket_dev->dev_info.name,
1424                         PTR_ERR(gasket_dev->dev_info.device));
1425                 ret = -ENODEV;
1426                 goto free_gasket_dev;
1427         }
1428
1429         ret = gasket_sysfs_create_mapping(gasket_dev->dev_info.device,
1430                                           gasket_dev);
1431         if (ret)
1432                 goto remove_device;
1433
1434         ret = gasket_sysfs_create_entries(gasket_dev->dev_info.device,
1435                                           gasket_sysfs_generic_attrs);
1436         if (ret)
1437                 goto remove_sysfs_mapping;
1438
1439         *gasket_devp = gasket_dev;
1440         return 0;
1441
1442 remove_sysfs_mapping:
1443         gasket_sysfs_remove_mapping(gasket_dev->dev_info.device);
1444 remove_device:
1445         device_destroy(internal_desc->class, gasket_dev->dev_info.devt);
1446 free_gasket_dev:
1447         gasket_free_dev(gasket_dev);
1448         return ret;
1449 }
1450
1451 static void __gasket_remove_device(struct gasket_internal_desc *internal_desc,
1452                                    struct gasket_dev *gasket_dev)
1453 {
1454         gasket_sysfs_remove_mapping(gasket_dev->dev_info.device);
1455         device_destroy(internal_desc->class, gasket_dev->dev_info.devt);
1456         gasket_free_dev(gasket_dev);
1457 }
1458
1459 /*
1460  * Add PCI gasket device.
1461  *
1462  * Called by Gasket device probe function.
1463  * Allocates device metadata and maps device memory.  The device driver must
1464  * call gasket_enable_device after driver init is complete to place the device
1465  * in active use.
1466  */
1467 int gasket_pci_add_device(struct pci_dev *pci_dev,
1468                           struct gasket_dev **gasket_devp)
1469 {
1470         int ret;
1471         struct gasket_internal_desc *internal_desc;
1472         struct gasket_dev *gasket_dev;
1473         struct device *parent;
1474
1475         dev_dbg(&pci_dev->dev, "add PCI gasket device\n");
1476
1477         mutex_lock(&g_mutex);
1478         internal_desc = lookup_pci_internal_desc(pci_dev);
1479         mutex_unlock(&g_mutex);
1480         if (!internal_desc) {
1481                 dev_err(&pci_dev->dev,
1482                         "PCI add device called for unknown driver type\n");
1483                 return -ENODEV;
1484         }
1485
1486         parent = &pci_dev->dev;
1487         ret = __gasket_add_device(parent, internal_desc, &gasket_dev);
1488         if (ret)
1489                 return ret;
1490
1491         gasket_dev->pci_dev = pci_dev;
1492         ret = gasket_setup_pci(pci_dev, gasket_dev);
1493         if (ret)
1494                 goto cleanup_pci;
1495
1496         /*
1497          * Once we've created the mapping structures successfully, attempt to
1498          * create a symlink to the pci directory of this object.
1499          */
1500         ret = sysfs_create_link(&gasket_dev->dev_info.device->kobj,
1501                                 &pci_dev->dev.kobj, dev_name(&pci_dev->dev));
1502         if (ret) {
1503                 dev_err(gasket_dev->dev,
1504                         "Cannot create sysfs pci link: %d\n", ret);
1505                 goto cleanup_pci;
1506         }
1507
1508         *gasket_devp = gasket_dev;
1509         return 0;
1510
1511 cleanup_pci:
1512         gasket_cleanup_pci(gasket_dev);
1513         __gasket_remove_device(internal_desc, gasket_dev);
1514         return ret;
1515 }
1516 EXPORT_SYMBOL(gasket_pci_add_device);
1517
1518 /* Remove a PCI gasket device. */
1519 void gasket_pci_remove_device(struct pci_dev *pci_dev)
1520 {
1521         int i;
1522         struct gasket_internal_desc *internal_desc;
1523         struct gasket_dev *gasket_dev = NULL;
1524         /* Find the device desc. */
1525         mutex_lock(&g_mutex);
1526         internal_desc = lookup_pci_internal_desc(pci_dev);
1527         if (!internal_desc) {
1528                 mutex_unlock(&g_mutex);
1529                 return;
1530         }
1531         mutex_unlock(&g_mutex);
1532
1533         /* Now find the specific device */
1534         mutex_lock(&internal_desc->mutex);
1535         for (i = 0; i < GASKET_DEV_MAX; i++) {
1536                 if (internal_desc->devs[i] &&
1537                     internal_desc->devs[i]->pci_dev == pci_dev) {
1538                         gasket_dev = internal_desc->devs[i];
1539                         break;
1540                 }
1541         }
1542         mutex_unlock(&internal_desc->mutex);
1543
1544         if (!gasket_dev)
1545                 return;
1546
1547         dev_dbg(gasket_dev->dev, "remove %s PCI gasket device\n",
1548                 internal_desc->driver_desc->name);
1549
1550         gasket_cleanup_pci(gasket_dev);
1551         __gasket_remove_device(internal_desc, gasket_dev);
1552 }
1553 EXPORT_SYMBOL(gasket_pci_remove_device);
1554
1555 /**
1556  * Lookup a name by number in a num_name table.
1557  * @num: Number to lookup.
1558  * @table: Array of num_name structures, the table for the lookup.
1559  *
1560  * Description: Searches for num in the table.  If found, the
1561  *              corresponding name is returned; otherwise NULL
1562  *              is returned.
1563  *
1564  *              The table must have a NULL name pointer at the end.
1565  */
1566 const char *gasket_num_name_lookup(uint num,
1567                                    const struct gasket_num_name *table)
1568 {
1569         uint i = 0;
1570
1571         while (table[i].snn_name) {
1572                 if (num == table[i].snn_num)
1573                         break;
1574                 ++i;
1575         }
1576
1577         return table[i].snn_name;
1578 }
1579 EXPORT_SYMBOL(gasket_num_name_lookup);
1580
1581 int gasket_reset(struct gasket_dev *gasket_dev)
1582 {
1583         int ret;
1584
1585         mutex_lock(&gasket_dev->mutex);
1586         ret = gasket_reset_nolock(gasket_dev);
1587         mutex_unlock(&gasket_dev->mutex);
1588         return ret;
1589 }
1590 EXPORT_SYMBOL(gasket_reset);
1591
1592 int gasket_reset_nolock(struct gasket_dev *gasket_dev)
1593 {
1594         int ret;
1595         int i;
1596         const struct gasket_driver_desc *driver_desc;
1597
1598         driver_desc = gasket_dev->internal_desc->driver_desc;
1599         if (!driver_desc->device_reset_cb)
1600                 return 0;
1601
1602         ret = driver_desc->device_reset_cb(gasket_dev);
1603         if (ret) {
1604                 dev_dbg(gasket_dev->dev, "Device reset cb returned %d.\n",
1605                         ret);
1606                 return ret;
1607         }
1608
1609         /* Reinitialize the page tables and interrupt framework. */
1610         for (i = 0; i < driver_desc->num_page_tables; ++i)
1611                 gasket_page_table_reset(gasket_dev->page_table[i]);
1612
1613         ret = gasket_interrupt_reinit(gasket_dev);
1614         if (ret) {
1615                 dev_dbg(gasket_dev->dev, "Unable to reinit interrupts: %d.\n",
1616                         ret);
1617                 return ret;
1618         }
1619
1620         /* Get current device health. */
1621         gasket_dev->status = gasket_get_hw_status(gasket_dev);
1622         if (gasket_dev->status == GASKET_STATUS_DEAD) {
1623                 dev_dbg(gasket_dev->dev, "Device reported as dead.\n");
1624                 return -EINVAL;
1625         }
1626
1627         return 0;
1628 }
1629 EXPORT_SYMBOL(gasket_reset_nolock);
1630
1631 gasket_ioctl_permissions_cb_t
1632 gasket_get_ioctl_permissions_cb(struct gasket_dev *gasket_dev)
1633 {
1634         return gasket_dev->internal_desc->driver_desc->ioctl_permissions_cb;
1635 }
1636 EXPORT_SYMBOL(gasket_get_ioctl_permissions_cb);
1637
1638 /* Get the driver structure for a given gasket_dev.
1639  * @dev: pointer to gasket_dev, implementing the requested driver.
1640  */
1641 const struct gasket_driver_desc *gasket_get_driver_desc(struct gasket_dev *dev)
1642 {
1643         return dev->internal_desc->driver_desc;
1644 }
1645
1646 /* Get the device structure for a given gasket_dev.
1647  * @dev: pointer to gasket_dev, implementing the requested driver.
1648  */
1649 struct device *gasket_get_device(struct gasket_dev *dev)
1650 {
1651         return dev->dev;
1652 }
1653
1654 /**
1655  * Asynchronously waits on device.
1656  * @gasket_dev: Device struct.
1657  * @bar: Bar
1658  * @offset: Register offset
1659  * @mask: Register mask
1660  * @val: Expected value
1661  * @max_retries: number of sleep periods
1662  * @delay_ms: Timeout in milliseconds
1663  *
1664  * Description: Busy waits for a specific combination of bits to be set on a
1665  * Gasket register.
1666  **/
1667 int gasket_wait_with_reschedule(struct gasket_dev *gasket_dev, int bar,
1668                                 u64 offset, u64 mask, u64 val,
1669                                 uint max_retries, u64 delay_ms)
1670 {
1671         uint retries = 0;
1672         u64 tmp;
1673
1674         while (retries < max_retries) {
1675                 tmp = gasket_dev_read_64(gasket_dev, bar, offset);
1676                 if ((tmp & mask) == val)
1677                         return 0;
1678                 msleep(delay_ms);
1679                 retries++;
1680         }
1681         dev_dbg(gasket_dev->dev, "%s timeout: reg %llx timeout (%llu ms)\n",
1682                 __func__, offset, max_retries * delay_ms);
1683         return -ETIMEDOUT;
1684 }
1685 EXPORT_SYMBOL(gasket_wait_with_reschedule);
1686
1687 /* See gasket_core.h for description. */
1688 int gasket_register_device(const struct gasket_driver_desc *driver_desc)
1689 {
1690         int i, ret;
1691         int desc_idx = -1;
1692         struct gasket_internal_desc *internal;
1693
1694         pr_debug("Loading %s driver version %s\n", driver_desc->name,
1695                  driver_desc->driver_version);
1696         /* Check for duplicates and find a free slot. */
1697         mutex_lock(&g_mutex);
1698
1699         for (i = 0; i < GASKET_FRAMEWORK_DESC_MAX; i++) {
1700                 if (g_descs[i].driver_desc == driver_desc) {
1701                         pr_err("%s driver already loaded/registered\n",
1702                                driver_desc->name);
1703                         mutex_unlock(&g_mutex);
1704                         return -EBUSY;
1705                 }
1706         }
1707
1708         /* This and the above loop could be combined, but this reads easier. */
1709         for (i = 0; i < GASKET_FRAMEWORK_DESC_MAX; i++) {
1710                 if (!g_descs[i].driver_desc) {
1711                         g_descs[i].driver_desc = driver_desc;
1712                         desc_idx = i;
1713                         break;
1714                 }
1715         }
1716         mutex_unlock(&g_mutex);
1717
1718         if (desc_idx == -1) {
1719                 pr_err("too many drivers loaded, max %d\n",
1720                        GASKET_FRAMEWORK_DESC_MAX);
1721                 return -EBUSY;
1722         }
1723
1724         internal = &g_descs[desc_idx];
1725         mutex_init(&internal->mutex);
1726         memset(internal->devs, 0, sizeof(struct gasket_dev *) * GASKET_DEV_MAX);
1727         internal->class =
1728                 class_create(driver_desc->module, driver_desc->name);
1729
1730         if (IS_ERR(internal->class)) {
1731                 pr_err("Cannot register %s class [ret=%ld]\n",
1732                        driver_desc->name, PTR_ERR(internal->class));
1733                 ret = PTR_ERR(internal->class);
1734                 goto unregister_gasket_driver;
1735         }
1736
1737         ret = register_chrdev_region(MKDEV(driver_desc->major,
1738                                            driver_desc->minor), GASKET_DEV_MAX,
1739                                      driver_desc->name);
1740         if (ret) {
1741                 pr_err("cannot register %s char driver [ret=%d]\n",
1742                        driver_desc->name, ret);
1743                 goto destroy_class;
1744         }
1745
1746         return 0;
1747
1748 destroy_class:
1749         class_destroy(internal->class);
1750
1751 unregister_gasket_driver:
1752         mutex_lock(&g_mutex);
1753         g_descs[desc_idx].driver_desc = NULL;
1754         mutex_unlock(&g_mutex);
1755         return ret;
1756 }
1757 EXPORT_SYMBOL(gasket_register_device);
1758
1759 /* See gasket_core.h for description. */
1760 void gasket_unregister_device(const struct gasket_driver_desc *driver_desc)
1761 {
1762         int i, desc_idx;
1763         struct gasket_internal_desc *internal_desc = NULL;
1764
1765         mutex_lock(&g_mutex);
1766         for (i = 0; i < GASKET_FRAMEWORK_DESC_MAX; i++) {
1767                 if (g_descs[i].driver_desc == driver_desc) {
1768                         internal_desc = &g_descs[i];
1769                         desc_idx = i;
1770                         break;
1771                 }
1772         }
1773
1774         if (!internal_desc) {
1775                 mutex_unlock(&g_mutex);
1776                 pr_err("request to unregister unknown desc: %s, %d:%d\n",
1777                        driver_desc->name, driver_desc->major,
1778                        driver_desc->minor);
1779                 return;
1780         }
1781
1782         unregister_chrdev_region(MKDEV(driver_desc->major, driver_desc->minor),
1783                                  GASKET_DEV_MAX);
1784
1785         class_destroy(internal_desc->class);
1786
1787         /* Finally, effectively "remove" the driver. */
1788         g_descs[desc_idx].driver_desc = NULL;
1789         mutex_unlock(&g_mutex);
1790
1791         pr_debug("removed %s driver\n", driver_desc->name);
1792 }
1793 EXPORT_SYMBOL(gasket_unregister_device);
1794
1795 static int __init gasket_init(void)
1796 {
1797         int i;
1798
1799         mutex_lock(&g_mutex);
1800         for (i = 0; i < GASKET_FRAMEWORK_DESC_MAX; i++) {
1801                 g_descs[i].driver_desc = NULL;
1802                 mutex_init(&g_descs[i].mutex);
1803         }
1804
1805         gasket_sysfs_init();
1806
1807         mutex_unlock(&g_mutex);
1808         return 0;
1809 }
1810
1811 MODULE_DESCRIPTION("Google Gasket driver framework");
1812 MODULE_VERSION(GASKET_FRAMEWORK_VERSION);
1813 MODULE_LICENSE("GPL v2");
1814 MODULE_AUTHOR("Rob Springer <rspringer@google.com>");
1815 module_init(gasket_init);