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