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/io.h> 15 #include <linux/slab.h> 16 #include <linux/mutex.h> 17 #include <linux/efi.h> 18 #include <linux/vmalloc.h> 19 20 #define NO_FURTHER_WRITE_ACTION -1 21 22 /** 23 * efi_free_all_buff_pages - free all previous allocated buffer pages 24 * @cap_info: pointer to current instance of capsule_info structure 25 * 26 * In addition to freeing buffer pages, it flags NO_FURTHER_WRITE_ACTION 27 * to cease processing data in subsequent write(2) calls until close(2) 28 * is called. 29 **/ 30 static void efi_free_all_buff_pages(struct capsule_info *cap_info) 31 { 32 while (cap_info->index > 0) 33 __free_page(cap_info->pages[--cap_info->index]); 34 35 cap_info->index = NO_FURTHER_WRITE_ACTION; 36 } 37 38 int __efi_capsule_setup_info(struct capsule_info *cap_info) 39 { 40 size_t pages_needed; 41 int ret; 42 void *temp_page; 43 44 pages_needed = ALIGN(cap_info->total_size, PAGE_SIZE) / PAGE_SIZE; 45 46 if (pages_needed == 0) { 47 pr_err("invalid capsule size\n"); 48 return -EINVAL; 49 } 50 51 /* Check if the capsule binary supported */ 52 ret = efi_capsule_supported(cap_info->header.guid, 53 cap_info->header.flags, 54 cap_info->header.imagesize, 55 &cap_info->reset_type); 56 if (ret) { 57 pr_err("capsule not supported\n"); 58 return ret; 59 } 60 61 temp_page = krealloc(cap_info->pages, 62 pages_needed * sizeof(void *), 63 GFP_KERNEL | __GFP_ZERO); 64 if (!temp_page) 65 return -ENOMEM; 66 67 cap_info->pages = temp_page; 68 69 temp_page = krealloc(cap_info->phys, 70 pages_needed * sizeof(phys_addr_t *), 71 GFP_KERNEL | __GFP_ZERO); 72 if (!temp_page) 73 return -ENOMEM; 74 75 cap_info->phys = temp_page; 76 77 return 0; 78 } 79 80 /** 81 * efi_capsule_setup_info - obtain the efi capsule header in the binary and 82 * setup capsule_info structure 83 * @cap_info: pointer to current instance of capsule_info structure 84 * @kbuff: a mapped first page buffer pointer 85 * @hdr_bytes: the total received number of bytes for efi header 86 * 87 * Platforms with non-standard capsule update mechanisms can override 88 * this __weak function so they can perform any required capsule 89 * image munging. See quark_quirk_function() for an example. 90 **/ 91 int __weak efi_capsule_setup_info(struct capsule_info *cap_info, void *kbuff, 92 size_t hdr_bytes) 93 { 94 /* Only process data block that is larger than efi header size */ 95 if (hdr_bytes < sizeof(efi_capsule_header_t)) 96 return 0; 97 98 memcpy(&cap_info->header, kbuff, sizeof(cap_info->header)); 99 cap_info->total_size = cap_info->header.imagesize; 100 101 return __efi_capsule_setup_info(cap_info); 102 } 103 104 /** 105 * efi_capsule_submit_update - invoke the efi_capsule_update API once binary 106 * upload done 107 * @cap_info: pointer to current instance of capsule_info structure 108 **/ 109 static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info) 110 { 111 bool do_vunmap = false; 112 int ret; 113 114 /* 115 * cap_info->capsule may have been assigned already by a quirk 116 * handler, so only overwrite it if it is NULL 117 */ 118 if (!cap_info->capsule) { 119 cap_info->capsule = vmap(cap_info->pages, cap_info->index, 120 VM_MAP, PAGE_KERNEL); 121 if (!cap_info->capsule) 122 return -ENOMEM; 123 do_vunmap = true; 124 } 125 126 ret = efi_capsule_update(cap_info->capsule, cap_info->phys); 127 if (do_vunmap) 128 vunmap(cap_info->capsule); 129 if (ret) { 130 pr_err("capsule update failed\n"); 131 return ret; 132 } 133 134 /* Indicate capsule binary uploading is done */ 135 cap_info->index = NO_FURTHER_WRITE_ACTION; 136 137 if (cap_info->header.flags & EFI_CAPSULE_PERSIST_ACROSS_RESET) { 138 pr_info("Successfully uploaded capsule file with reboot type '%s'\n", 139 !cap_info->reset_type ? "RESET_COLD" : 140 cap_info->reset_type == 1 ? "RESET_WARM" : 141 "RESET_SHUTDOWN"); 142 } else { 143 pr_info("Successfully processed capsule file\n"); 144 } 145 146 return 0; 147 } 148 149 /** 150 * efi_capsule_write - store the capsule binary and pass it to 151 * efi_capsule_update() API 152 * @file: file pointer 153 * @buff: buffer pointer 154 * @count: number of bytes in @buff 155 * @offp: not used 156 * 157 * Expectation: 158 * - A user space tool should start at the beginning of capsule binary and 159 * pass data in sequentially. 160 * - Users should close and re-open this file note in order to upload more 161 * capsules. 162 * - After an error returned, user should close the file and restart the 163 * operation for the next try otherwise -EIO will be returned until the 164 * file is closed. 165 * - An EFI capsule header must be located at the beginning of capsule 166 * binary file and passed in as first block data of write operation. 167 **/ 168 static ssize_t efi_capsule_write(struct file *file, const char __user *buff, 169 size_t count, loff_t *offp) 170 { 171 int ret; 172 struct capsule_info *cap_info = file->private_data; 173 struct page *page; 174 void *kbuff = NULL; 175 size_t write_byte; 176 177 if (count == 0) 178 return 0; 179 180 /* Return error while NO_FURTHER_WRITE_ACTION is flagged */ 181 if (cap_info->index < 0) 182 return -EIO; 183 184 /* Only alloc a new page when previous page is full */ 185 if (!cap_info->page_bytes_remain) { 186 page = alloc_page(GFP_KERNEL); 187 if (!page) { 188 ret = -ENOMEM; 189 goto failed; 190 } 191 192 cap_info->pages[cap_info->index] = page; 193 cap_info->phys[cap_info->index] = page_to_phys(page); 194 cap_info->page_bytes_remain = PAGE_SIZE; 195 cap_info->index++; 196 } else { 197 page = cap_info->pages[cap_info->index - 1]; 198 } 199 200 kbuff = kmap(page); 201 kbuff += PAGE_SIZE - cap_info->page_bytes_remain; 202 203 /* Copy capsule binary data from user space to kernel space buffer */ 204 write_byte = min_t(size_t, count, cap_info->page_bytes_remain); 205 if (copy_from_user(kbuff, buff, write_byte)) { 206 ret = -EFAULT; 207 goto fail_unmap; 208 } 209 cap_info->page_bytes_remain -= write_byte; 210 211 /* Setup capsule binary info structure */ 212 if (cap_info->header.headersize == 0) { 213 ret = efi_capsule_setup_info(cap_info, kbuff - cap_info->count, 214 cap_info->count + write_byte); 215 if (ret) 216 goto fail_unmap; 217 } 218 219 cap_info->count += write_byte; 220 kunmap(page); 221 222 /* Submit the full binary to efi_capsule_update() API */ 223 if (cap_info->header.headersize > 0 && 224 cap_info->count >= cap_info->total_size) { 225 if (cap_info->count > cap_info->total_size) { 226 pr_err("capsule upload size exceeded header defined size\n"); 227 ret = -EINVAL; 228 goto failed; 229 } 230 231 ret = efi_capsule_submit_update(cap_info); 232 if (ret) 233 goto failed; 234 } 235 236 return write_byte; 237 238 fail_unmap: 239 kunmap(page); 240 failed: 241 efi_free_all_buff_pages(cap_info); 242 return ret; 243 } 244 245 /** 246 * efi_capsule_release - called by file close 247 * @inode: not used 248 * @file: file pointer 249 * 250 * We will not free successfully submitted pages since efi update 251 * requires data to be maintained across system reboot. 252 **/ 253 static int efi_capsule_release(struct inode *inode, struct file *file) 254 { 255 struct capsule_info *cap_info = file->private_data; 256 257 if (cap_info->index > 0 && 258 (cap_info->header.headersize == 0 || 259 cap_info->count < cap_info->total_size)) { 260 pr_err("capsule upload not complete\n"); 261 efi_free_all_buff_pages(cap_info); 262 } 263 264 kfree(cap_info->pages); 265 kfree(cap_info->phys); 266 kfree(file->private_data); 267 file->private_data = NULL; 268 return 0; 269 } 270 271 /** 272 * efi_capsule_open - called by file open 273 * @inode: not used 274 * @file: file pointer 275 * 276 * Will allocate each capsule_info memory for each file open call. 277 * This provided the capability to support multiple file open feature 278 * where user is not needed to wait for others to finish in order to 279 * upload their capsule binary. 280 **/ 281 static int efi_capsule_open(struct inode *inode, struct file *file) 282 { 283 struct capsule_info *cap_info; 284 285 cap_info = kzalloc(sizeof(*cap_info), GFP_KERNEL); 286 if (!cap_info) 287 return -ENOMEM; 288 289 cap_info->pages = kzalloc(sizeof(void *), GFP_KERNEL); 290 if (!cap_info->pages) { 291 kfree(cap_info); 292 return -ENOMEM; 293 } 294 295 cap_info->phys = kzalloc(sizeof(phys_addr_t), GFP_KERNEL); 296 if (!cap_info->phys) { 297 kfree(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 .release = efi_capsule_release, 312 }; 313 314 static struct miscdevice efi_capsule_misc = { 315 .minor = MISC_DYNAMIC_MINOR, 316 .name = "efi_capsule_loader", 317 .fops = &efi_capsule_fops, 318 }; 319 320 static int __init efi_capsule_loader_init(void) 321 { 322 int ret; 323 324 if (!efi_enabled(EFI_RUNTIME_SERVICES)) 325 return -ENODEV; 326 327 ret = misc_register(&efi_capsule_misc); 328 if (ret) 329 pr_err("Unable to register capsule loader device\n"); 330 331 return ret; 332 } 333 module_init(efi_capsule_loader_init); 334 335 static void __exit efi_capsule_loader_exit(void) 336 { 337 misc_deregister(&efi_capsule_misc); 338 } 339 module_exit(efi_capsule_loader_exit); 340 341 MODULE_DESCRIPTION("EFI capsule firmware binary loader"); 342 MODULE_LICENSE("GPL v2"); 343