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 return -ENOMEM; 93 94 cap_info->pages = temp_page; 95 cap_info->header_obtained = true; 96 97 return 0; 98 } 99 100 /** 101 * efi_capsule_submit_update - invoke the efi_capsule_update API once binary 102 * upload done 103 * @cap_info: pointer to current instance of capsule_info structure 104 **/ 105 static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info) 106 { 107 int ret; 108 void *cap_hdr_temp; 109 110 cap_hdr_temp = vmap(cap_info->pages, cap_info->index, 111 VM_MAP, PAGE_KERNEL); 112 if (!cap_hdr_temp) 113 return -ENOMEM; 114 115 ret = efi_capsule_update(cap_hdr_temp, cap_info->pages); 116 vunmap(cap_hdr_temp); 117 if (ret) { 118 pr_err("%s: efi_capsule_update() failed\n", __func__); 119 return ret; 120 } 121 122 /* Indicate capsule binary uploading is done */ 123 cap_info->index = NO_FURTHER_WRITE_ACTION; 124 pr_info("%s: Successfully upload capsule file with reboot type '%s'\n", 125 __func__, !cap_info->reset_type ? "RESET_COLD" : 126 cap_info->reset_type == 1 ? "RESET_WARM" : 127 "RESET_SHUTDOWN"); 128 return 0; 129 } 130 131 /** 132 * efi_capsule_write - store the capsule binary and pass it to 133 * efi_capsule_update() API 134 * @file: file pointer 135 * @buff: buffer pointer 136 * @count: number of bytes in @buff 137 * @offp: not used 138 * 139 * Expectation: 140 * - A user space tool should start at the beginning of capsule binary and 141 * pass data in sequentially. 142 * - Users should close and re-open this file note in order to upload more 143 * capsules. 144 * - After an error returned, user should close the file and restart the 145 * operation for the next try otherwise -EIO will be returned until the 146 * file is closed. 147 * - An EFI capsule header must be located at the beginning of capsule 148 * binary file and passed in as first block data of write operation. 149 **/ 150 static ssize_t efi_capsule_write(struct file *file, const char __user *buff, 151 size_t count, loff_t *offp) 152 { 153 int ret = 0; 154 struct capsule_info *cap_info = file->private_data; 155 struct page *page; 156 void *kbuff = NULL; 157 size_t write_byte; 158 159 if (count == 0) 160 return 0; 161 162 /* Return error while NO_FURTHER_WRITE_ACTION is flagged */ 163 if (cap_info->index < 0) 164 return -EIO; 165 166 /* Only alloc a new page when previous page is full */ 167 if (!cap_info->page_bytes_remain) { 168 page = alloc_page(GFP_KERNEL); 169 if (!page) { 170 ret = -ENOMEM; 171 goto failed; 172 } 173 174 cap_info->pages[cap_info->index++] = page; 175 cap_info->page_bytes_remain = PAGE_SIZE; 176 } 177 178 page = cap_info->pages[cap_info->index - 1]; 179 180 kbuff = kmap(page); 181 if (!kbuff) { 182 ret = -ENOMEM; 183 goto failed; 184 } 185 kbuff += PAGE_SIZE - cap_info->page_bytes_remain; 186 187 /* Copy capsule binary data from user space to kernel space buffer */ 188 write_byte = min_t(size_t, count, cap_info->page_bytes_remain); 189 if (copy_from_user(kbuff, buff, write_byte)) { 190 ret = -EFAULT; 191 goto fail_unmap; 192 } 193 cap_info->page_bytes_remain -= write_byte; 194 195 /* Setup capsule binary info structure */ 196 if (!cap_info->header_obtained) { 197 ret = efi_capsule_setup_info(cap_info, kbuff, 198 cap_info->count + write_byte); 199 if (ret) 200 goto fail_unmap; 201 } 202 203 cap_info->count += write_byte; 204 kunmap(page); 205 206 /* Submit the full binary to efi_capsule_update() API */ 207 if (cap_info->header_obtained && 208 cap_info->count >= cap_info->total_size) { 209 if (cap_info->count > cap_info->total_size) { 210 pr_err("%s: upload size exceeded header defined size\n", 211 __func__); 212 ret = -EINVAL; 213 goto failed; 214 } 215 216 ret = efi_capsule_submit_update(cap_info); 217 if (ret) 218 goto failed; 219 } 220 221 return write_byte; 222 223 fail_unmap: 224 kunmap(page); 225 failed: 226 efi_free_all_buff_pages(cap_info); 227 return ret; 228 } 229 230 /** 231 * efi_capsule_flush - called by file close or file flush 232 * @file: file pointer 233 * @id: not used 234 * 235 * If a capsule is being partially uploaded then calling this function 236 * will be treated as upload termination and will free those completed 237 * buffer pages and -ECANCELED will be returned. 238 **/ 239 static int efi_capsule_flush(struct file *file, fl_owner_t id) 240 { 241 int ret = 0; 242 struct capsule_info *cap_info = file->private_data; 243 244 if (cap_info->index > 0) { 245 pr_err("%s: capsule upload not complete\n", __func__); 246 efi_free_all_buff_pages(cap_info); 247 ret = -ECANCELED; 248 } 249 250 return ret; 251 } 252 253 /** 254 * efi_capsule_release - called by file close 255 * @inode: not used 256 * @file: file pointer 257 * 258 * We will not free successfully submitted pages since efi update 259 * requires data to be maintained across system reboot. 260 **/ 261 static int efi_capsule_release(struct inode *inode, struct file *file) 262 { 263 struct capsule_info *cap_info = file->private_data; 264 265 kfree(cap_info->pages); 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 file->private_data = cap_info; 296 297 return 0; 298 } 299 300 static const struct file_operations efi_capsule_fops = { 301 .owner = THIS_MODULE, 302 .open = efi_capsule_open, 303 .write = efi_capsule_write, 304 .flush = efi_capsule_flush, 305 .release = efi_capsule_release, 306 .llseek = no_llseek, 307 }; 308 309 static struct miscdevice efi_capsule_misc = { 310 .minor = MISC_DYNAMIC_MINOR, 311 .name = "efi_capsule_loader", 312 .fops = &efi_capsule_fops, 313 }; 314 315 static int __init efi_capsule_loader_init(void) 316 { 317 int ret; 318 319 if (!efi_enabled(EFI_RUNTIME_SERVICES)) 320 return -ENODEV; 321 322 ret = misc_register(&efi_capsule_misc); 323 if (ret) 324 pr_err("%s: Failed to register misc char file note\n", 325 __func__); 326 327 return ret; 328 } 329 module_init(efi_capsule_loader_init); 330 331 static void __exit efi_capsule_loader_exit(void) 332 { 333 misc_deregister(&efi_capsule_misc); 334 } 335 module_exit(efi_capsule_loader_exit); 336 337 MODULE_DESCRIPTION("EFI capsule firmware binary loader"); 338 MODULE_LICENSE("GPL v2"); 339