drivers/firmware/efi/capsule-loader.c

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