drivers/firmware/efi/capsule-loader.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * EFI capsule loader driver.
   4  *
   5  * Copyright 2015 Intel Corporation
   6  */
   7
   8 #define pr_fmt(fmt) "efi: " fmt
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/miscdevice.h>
  13 #include <linux/highmem.h>
  14 #include <linux/io.h>
  15 #include <linux/slab.h>
  16 #include <linux/mutex.h>
  17 #include <linux/efi.h>
  18 #include <linux/vmalloc.h>
  19
  20 #define NO_FURTHER_WRITE_ACTION -1
  21
  22 /**
  23  * efi_free_all_buff_pages - free all previous allocated buffer pages
  24  * @cap_info: pointer to current instance of capsule_info structure
  25  *
  26  *      In addition to freeing buffer pages, it flags NO_FURTHER_WRITE_ACTION
  27  *      to cease processing data in subsequent write(2) calls until close(2)
  28  *      is called.
  29  **/
  30 static void efi_free_all_buff_pages(struct capsule_info *cap_info)
  31 {
  32         while (cap_info->index > 0)
  33                 __free_page(cap_info->pages[--cap_info->index]);
  34
  35         cap_info->index = NO_FURTHER_WRITE_ACTION;
  36 }
  37
  38 int __efi_capsule_setup_info(struct capsule_info *cap_info)
  39 {
  40         size_t pages_needed;
  41         int ret;
  42         void *temp_page;
  43
  44         pages_needed = ALIGN(cap_info->total_size, PAGE_SIZE) / PAGE_SIZE;
  45
  46         if (pages_needed == 0) {
  47                 pr_err("invalid capsule size\n");
  48                 return -EINVAL;
  49         }
  50
  51         /* Check if the capsule binary supported */
  52         ret = efi_capsule_supported(cap_info->header.guid,
  53                                     cap_info->header.flags,
  54                                     cap_info->header.imagesize,
  55                                     &cap_info->reset_type);
  56         if (ret) {
  57                 pr_err("capsule not supported\n");
  58                 return ret;
  59         }
  60
  61         temp_page = krealloc(cap_info->pages,
  62                              pages_needed * sizeof(void *),
  63                              GFP_KERNEL | __GFP_ZERO);
  64         if (!temp_page)
  65                 return -ENOMEM;
  66
  67         cap_info->pages = temp_page;
  68
  69         temp_page = krealloc(cap_info->phys,
  70                              pages_needed * sizeof(phys_addr_t *),
  71                              GFP_KERNEL | __GFP_ZERO);
  72         if (!temp_page)
  73                 return -ENOMEM;
  74
  75         cap_info->phys = temp_page;
  76
  77         return 0;
  78 }
  79
  80 /**
  81  * efi_capsule_setup_info - obtain the efi capsule header in the binary and
  82  *                          setup capsule_info structure
  83  * @cap_info: pointer to current instance of capsule_info structure
  84  * @kbuff: a mapped first page buffer pointer
  85  * @hdr_bytes: the total received number of bytes for efi header
  86  *
  87  * Platforms with non-standard capsule update mechanisms can override
  88  * this __weak function so they can perform any required capsule
  89  * image munging. See quark_quirk_function() for an example.
  90  **/
  91 int __weak efi_capsule_setup_info(struct capsule_info *cap_info, void *kbuff,
  92                                   size_t hdr_bytes)
  93 {
  94         /* Only process data block that is larger than efi header size */
  95         if (hdr_bytes < sizeof(efi_capsule_header_t))
  96                 return 0;
  97
  98         memcpy(&cap_info->header, kbuff, sizeof(cap_info->header));
  99         cap_info->total_size = cap_info->header.imagesize;
 100
 101         return __efi_capsule_setup_info(cap_info);
 102 }
 103
 104 /**
 105  * efi_capsule_submit_update - invoke the efi_capsule_update API once binary
 106  *                             upload done
 107  * @cap_info: pointer to current instance of capsule_info structure
 108  **/
 109 static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info)
 110 {
 111         bool do_vunmap = false;
 112         int ret;
 113
 114         /*
 115          * cap_info->capsule may have been assigned already by a quirk
 116          * handler, so only overwrite it if it is NULL
 117          */
 118         if (!cap_info->capsule) {
 119                 cap_info->capsule = vmap(cap_info->pages, cap_info->index,
 120                                          VM_MAP, PAGE_KERNEL);
 121                 if (!cap_info->capsule)
 122                         return -ENOMEM;
 123                 do_vunmap = true;
 124         }
 125
 126         ret = efi_capsule_update(cap_info->capsule, cap_info->phys);
 127         if (do_vunmap)
 128                 vunmap(cap_info->capsule);
 129         if (ret) {
 130                 pr_err("capsule update failed\n");
 131                 return ret;
 132         }
 133
 134         /* Indicate capsule binary uploading is done */
 135         cap_info->index = NO_FURTHER_WRITE_ACTION;
 136
 137         if (cap_info->header.flags & EFI_CAPSULE_PERSIST_ACROSS_RESET) {
 138                 pr_info("Successfully uploaded capsule file with reboot type '%s'\n",
 139                         !cap_info->reset_type ? "RESET_COLD" :
 140                         cap_info->reset_type == 1 ? "RESET_WARM" :
 141                         "RESET_SHUTDOWN");
 142         } else {
 143                 pr_info("Successfully processed capsule file\n");
 144         }
 145
 146         return 0;
 147 }
 148
 149 /**
 150  * efi_capsule_write - store the capsule binary and pass it to
 151  *                     efi_capsule_update() API
 152  * @file: file pointer
 153  * @buff: buffer pointer
 154  * @count: number of bytes in @buff
 155  * @offp: not used
 156  *
 157  *      Expectation:
 158  *      - A user space tool should start at the beginning of capsule binary and
 159  *        pass data in sequentially.
 160  *      - Users should close and re-open this file note in order to upload more
 161  *        capsules.
 162  *      - After an error returned, user should close the file and restart the
 163  *        operation for the next try otherwise -EIO will be returned until the
 164  *        file is closed.
 165  *      - An EFI capsule header must be located at the beginning of capsule
 166  *        binary file and passed in as first block data of write operation.
 167  **/
 168 static ssize_t efi_capsule_write(struct file *file, const char __user *buff,
 169                                  size_t count, loff_t *offp)
 170 {
 171         int ret;
 172         struct capsule_info *cap_info = file->private_data;
 173         struct page *page;
 174         void *kbuff = NULL;
 175         size_t write_byte;
 176
 177         if (count == 0)
 178                 return 0;
 179
 180         /* Return error while NO_FURTHER_WRITE_ACTION is flagged */
 181         if (cap_info->index < 0)
 182                 return -EIO;
 183
 184         /* Only alloc a new page when previous page is full */
 185         if (!cap_info->page_bytes_remain) {
 186                 page = alloc_page(GFP_KERNEL);
 187                 if (!page) {
 188                         ret = -ENOMEM;
 189                         goto failed;
 190                 }
 191
 192                 cap_info->pages[cap_info->index] = page;
 193                 cap_info->phys[cap_info->index] = page_to_phys(page);
 194                 cap_info->page_bytes_remain = PAGE_SIZE;
 195                 cap_info->index++;
 196         } else {
 197                 page = cap_info->pages[cap_info->index - 1];
 198         }
 199
 200         kbuff = kmap(page);
 201         kbuff += PAGE_SIZE - cap_info->page_bytes_remain;
 202
 203         /* Copy capsule binary data from user space to kernel space buffer */
 204         write_byte = min_t(size_t, count, cap_info->page_bytes_remain);
 205         if (copy_from_user(kbuff, buff, write_byte)) {
 206                 ret = -EFAULT;
 207                 goto fail_unmap;
 208         }
 209         cap_info->page_bytes_remain -= write_byte;
 210
 211         /* Setup capsule binary info structure */
 212         if (cap_info->header.headersize == 0) {
 213                 ret = efi_capsule_setup_info(cap_info, kbuff - cap_info->count,
 214                                              cap_info->count + write_byte);
 215                 if (ret)
 216                         goto fail_unmap;
 217         }
 218
 219         cap_info->count += write_byte;
 220         kunmap(page);
 221
 222         /* Submit the full binary to efi_capsule_update() API */
 223         if (cap_info->header.headersize > 0 &&
 224             cap_info->count >= cap_info->total_size) {
 225                 if (cap_info->count > cap_info->total_size) {
 226                         pr_err("capsule upload size exceeded header defined size\n");
 227                         ret = -EINVAL;
 228                         goto failed;
 229                 }
 230
 231                 ret = efi_capsule_submit_update(cap_info);
 232                 if (ret)
 233                         goto failed;
 234         }
 235
 236         return write_byte;
 237
 238 fail_unmap:
 239         kunmap(page);
 240 failed:
 241         efi_free_all_buff_pages(cap_info);
 242         return ret;
 243 }
 244
 245 /**
 246  * efi_capsule_flush - called by file close or file flush
 247  * @file: file pointer
 248  * @id: not used
 249  *
 250  *      If a capsule is being partially uploaded then calling this function
 251  *      will be treated as upload termination and will free those completed
 252  *      buffer pages and -ECANCELED will be returned.
 253  **/
 254 static int efi_capsule_flush(struct file *file, fl_owner_t id)
 255 {
 256         int ret = 0;
 257         struct capsule_info *cap_info = file->private_data;
 258
 259         if (cap_info->index > 0) {
 260                 pr_err("capsule upload not complete\n");
 261                 efi_free_all_buff_pages(cap_info);
 262                 ret = -ECANCELED;
 263         }
 264
 265         return ret;
 266 }
 267
 268 /**
 269  * efi_capsule_release - called by file close
 270  * @inode: not used
 271  * @file: file pointer
 272  *
 273  *      We will not free successfully submitted pages since efi update
 274  *      requires data to be maintained across system reboot.
 275  **/
 276 static int efi_capsule_release(struct inode *inode, struct file *file)
 277 {
 278         struct capsule_info *cap_info = file->private_data;
 279
 280         kfree(cap_info->pages);
 281         kfree(cap_info->phys);
 282         kfree(file->private_data);
 283         file->private_data = NULL;
 284         return 0;
 285 }
 286
 287 /**
 288  * efi_capsule_open - called by file open
 289  * @inode: not used
 290  * @file: file pointer
 291  *
 292  *      Will allocate each capsule_info memory for each file open call.
 293  *      This provided the capability to support multiple file open feature
 294  *      where user is not needed to wait for others to finish in order to
 295  *      upload their capsule binary.
 296  **/
 297 static int efi_capsule_open(struct inode *inode, struct file *file)
 298 {
 299         struct capsule_info *cap_info;
 300
 301         cap_info = kzalloc(sizeof(*cap_info), GFP_KERNEL);
 302         if (!cap_info)
 303                 return -ENOMEM;
 304
 305         cap_info->pages = kzalloc(sizeof(void *), GFP_KERNEL);
 306         if (!cap_info->pages) {
 307                 kfree(cap_info);
 308                 return -ENOMEM;
 309         }
 310
 311         cap_info->phys = kzalloc(sizeof(void *), GFP_KERNEL);
 312         if (!cap_info->phys) {
 313                 kfree(cap_info->pages);
 314                 kfree(cap_info);
 315                 return -ENOMEM;
 316         }
 317
 318         file->private_data = cap_info;
 319
 320         return 0;
 321 }
 322
 323 static const struct file_operations efi_capsule_fops = {
 324         .owner = THIS_MODULE,
 325         .open = efi_capsule_open,
 326         .write = efi_capsule_write,
 327         .flush = efi_capsule_flush,
 328         .release = efi_capsule_release,
 329         .llseek = no_llseek,
 330 };
 331
 332 static struct miscdevice efi_capsule_misc = {
 333         .minor = MISC_DYNAMIC_MINOR,
 334         .name = "efi_capsule_loader",
 335         .fops = &efi_capsule_fops,
 336 };
 337
 338 static int __init efi_capsule_loader_init(void)
 339 {
 340         int ret;
 341
 342         if (!efi_enabled(EFI_RUNTIME_SERVICES))
 343                 return -ENODEV;
 344
 345         ret = misc_register(&efi_capsule_misc);
 346         if (ret)
 347                 pr_err("Unable to register capsule loader device\n");
 348
 349         return ret;
 350 }
 351 module_init(efi_capsule_loader_init);
 352
 353 static void __exit efi_capsule_loader_exit(void)
 354 {
 355         misc_deregister(&efi_capsule_misc);
 356 }
 357 module_exit(efi_capsule_loader_exit);
 358
 359 MODULE_DESCRIPTION("EFI capsule firmware binary loader");
 360 MODULE_LICENSE("GPL v2");