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"); 360