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