root/drivers/firmware/efi/capsule-loader.c

DEFINITIONS

1. efi_free_all_buff_pages
2. __efi_capsule_setup_info
3. efi_capsule_setup_info
4. efi_capsule_submit_update
5. efi_capsule_write
6. efi_capsule_flush
7. efi_capsule_release
8. efi_capsule_open
9. efi_capsule_loader_init
10. efi_capsule_loader_exit

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