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