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65117f1a KHL |
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> | |
6862e6ad | 19 | #include <linux/vmalloc.h> |
65117f1a KHL |
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 | pr_debug("%s: krealloc() failed\n", __func__); | |
93 | return -ENOMEM; | |
94 | } | |
95 | ||
96 | cap_info->pages = temp_page; | |
97 | cap_info->header_obtained = true; | |
98 | ||
99 | return 0; | |
100 | } | |
101 | ||
102 | /** | |
103 | * efi_capsule_submit_update - invoke the efi_capsule_update API once binary | |
104 | * upload done | |
105 | * @cap_info: pointer to current instance of capsule_info structure | |
106 | **/ | |
107 | static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info) | |
108 | { | |
109 | int ret; | |
110 | void *cap_hdr_temp; | |
111 | ||
6862e6ad AC |
112 | cap_hdr_temp = vmap(cap_info->pages, cap_info->index, |
113 | VM_MAP, PAGE_KERNEL); | |
65117f1a | 114 | if (!cap_hdr_temp) { |
6862e6ad | 115 | pr_debug("%s: vmap() failed\n", __func__); |
65117f1a KHL |
116 | return -EFAULT; |
117 | } | |
118 | ||
119 | ret = efi_capsule_update(cap_hdr_temp, cap_info->pages); | |
6862e6ad | 120 | vunmap(cap_hdr_temp); |
65117f1a KHL |
121 | if (ret) { |
122 | pr_err("%s: efi_capsule_update() failed\n", __func__); | |
123 | return ret; | |
124 | } | |
125 | ||
126 | /* Indicate capsule binary uploading is done */ | |
127 | cap_info->index = NO_FURTHER_WRITE_ACTION; | |
128 | pr_info("%s: Successfully upload capsule file with reboot type '%s'\n", | |
129 | __func__, !cap_info->reset_type ? "RESET_COLD" : | |
130 | cap_info->reset_type == 1 ? "RESET_WARM" : | |
131 | "RESET_SHUTDOWN"); | |
132 | return 0; | |
133 | } | |
134 | ||
135 | /** | |
136 | * efi_capsule_write - store the capsule binary and pass it to | |
137 | * efi_capsule_update() API | |
138 | * @file: file pointer | |
139 | * @buff: buffer pointer | |
140 | * @count: number of bytes in @buff | |
141 | * @offp: not used | |
142 | * | |
143 | * Expectation: | |
144 | * - A user space tool should start at the beginning of capsule binary and | |
145 | * pass data in sequentially. | |
146 | * - Users should close and re-open this file note in order to upload more | |
147 | * capsules. | |
148 | * - After an error returned, user should close the file and restart the | |
149 | * operation for the next try otherwise -EIO will be returned until the | |
150 | * file is closed. | |
151 | * - An EFI capsule header must be located at the beginning of capsule | |
152 | * binary file and passed in as first block data of write operation. | |
153 | **/ | |
154 | static ssize_t efi_capsule_write(struct file *file, const char __user *buff, | |
155 | size_t count, loff_t *offp) | |
156 | { | |
157 | int ret = 0; | |
158 | struct capsule_info *cap_info = file->private_data; | |
159 | struct page *page; | |
160 | void *kbuff = NULL; | |
161 | size_t write_byte; | |
162 | ||
163 | if (count == 0) | |
164 | return 0; | |
165 | ||
166 | /* Return error while NO_FURTHER_WRITE_ACTION is flagged */ | |
167 | if (cap_info->index < 0) | |
168 | return -EIO; | |
169 | ||
170 | /* Only alloc a new page when previous page is full */ | |
171 | if (!cap_info->page_bytes_remain) { | |
172 | page = alloc_page(GFP_KERNEL); | |
173 | if (!page) { | |
174 | pr_debug("%s: alloc_page() failed\n", __func__); | |
175 | ret = -ENOMEM; | |
176 | goto failed; | |
177 | } | |
178 | ||
179 | cap_info->pages[cap_info->index++] = page; | |
180 | cap_info->page_bytes_remain = PAGE_SIZE; | |
181 | } | |
182 | ||
183 | page = cap_info->pages[cap_info->index - 1]; | |
184 | ||
185 | kbuff = kmap(page); | |
186 | if (!kbuff) { | |
187 | pr_debug("%s: kmap() failed\n", __func__); | |
188 | ret = -EFAULT; | |
189 | goto failed; | |
190 | } | |
191 | kbuff += PAGE_SIZE - cap_info->page_bytes_remain; | |
192 | ||
193 | /* Copy capsule binary data from user space to kernel space buffer */ | |
194 | write_byte = min_t(size_t, count, cap_info->page_bytes_remain); | |
195 | if (copy_from_user(kbuff, buff, write_byte)) { | |
196 | pr_debug("%s: copy_from_user() failed\n", __func__); | |
197 | ret = -EFAULT; | |
198 | goto fail_unmap; | |
199 | } | |
200 | cap_info->page_bytes_remain -= write_byte; | |
201 | ||
202 | /* Setup capsule binary info structure */ | |
203 | if (!cap_info->header_obtained) { | |
204 | ret = efi_capsule_setup_info(cap_info, kbuff, | |
205 | cap_info->count + write_byte); | |
206 | if (ret) | |
207 | goto fail_unmap; | |
208 | } | |
209 | ||
210 | cap_info->count += write_byte; | |
211 | kunmap(page); | |
212 | ||
213 | /* Submit the full binary to efi_capsule_update() API */ | |
214 | if (cap_info->header_obtained && | |
215 | cap_info->count >= cap_info->total_size) { | |
216 | if (cap_info->count > cap_info->total_size) { | |
217 | pr_err("%s: upload size exceeded header defined size\n", | |
218 | __func__); | |
219 | ret = -EINVAL; | |
220 | goto failed; | |
221 | } | |
222 | ||
223 | ret = efi_capsule_submit_update(cap_info); | |
224 | if (ret) | |
225 | goto failed; | |
226 | } | |
227 | ||
228 | return write_byte; | |
229 | ||
230 | fail_unmap: | |
231 | kunmap(page); | |
232 | failed: | |
233 | efi_free_all_buff_pages(cap_info); | |
234 | return ret; | |
235 | } | |
236 | ||
237 | /** | |
238 | * efi_capsule_flush - called by file close or file flush | |
239 | * @file: file pointer | |
240 | * @id: not used | |
241 | * | |
242 | * If a capsule is being partially uploaded then calling this function | |
243 | * will be treated as upload termination and will free those completed | |
244 | * buffer pages and -ECANCELED will be returned. | |
245 | **/ | |
246 | static int efi_capsule_flush(struct file *file, fl_owner_t id) | |
247 | { | |
248 | int ret = 0; | |
249 | struct capsule_info *cap_info = file->private_data; | |
250 | ||
251 | if (cap_info->index > 0) { | |
252 | pr_err("%s: capsule upload not complete\n", __func__); | |
253 | efi_free_all_buff_pages(cap_info); | |
254 | ret = -ECANCELED; | |
255 | } | |
256 | ||
257 | return ret; | |
258 | } | |
259 | ||
260 | /** | |
261 | * efi_capsule_release - called by file close | |
262 | * @inode: not used | |
263 | * @file: file pointer | |
264 | * | |
265 | * We will not free successfully submitted pages since efi update | |
266 | * requires data to be maintained across system reboot. | |
267 | **/ | |
268 | static int efi_capsule_release(struct inode *inode, struct file *file) | |
269 | { | |
270 | struct capsule_info *cap_info = file->private_data; | |
271 | ||
272 | kfree(cap_info->pages); | |
273 | kfree(file->private_data); | |
274 | file->private_data = NULL; | |
275 | return 0; | |
276 | } | |
277 | ||
278 | /** | |
279 | * efi_capsule_open - called by file open | |
280 | * @inode: not used | |
281 | * @file: file pointer | |
282 | * | |
283 | * Will allocate each capsule_info memory for each file open call. | |
284 | * This provided the capability to support multiple file open feature | |
285 | * where user is not needed to wait for others to finish in order to | |
286 | * upload their capsule binary. | |
287 | **/ | |
288 | static int efi_capsule_open(struct inode *inode, struct file *file) | |
289 | { | |
290 | struct capsule_info *cap_info; | |
291 | ||
292 | cap_info = kzalloc(sizeof(*cap_info), GFP_KERNEL); | |
293 | if (!cap_info) | |
294 | return -ENOMEM; | |
295 | ||
296 | cap_info->pages = kzalloc(sizeof(void *), GFP_KERNEL); | |
297 | if (!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 | .flush = efi_capsule_flush, | |
312 | .release = efi_capsule_release, | |
313 | .llseek = no_llseek, | |
314 | }; | |
315 | ||
316 | static struct miscdevice efi_capsule_misc = { | |
317 | .minor = MISC_DYNAMIC_MINOR, | |
318 | .name = "efi_capsule_loader", | |
319 | .fops = &efi_capsule_fops, | |
320 | }; | |
321 | ||
322 | static int __init efi_capsule_loader_init(void) | |
323 | { | |
324 | int ret; | |
325 | ||
326 | if (!efi_enabled(EFI_RUNTIME_SERVICES)) | |
327 | return -ENODEV; | |
328 | ||
329 | ret = misc_register(&efi_capsule_misc); | |
330 | if (ret) | |
331 | pr_err("%s: Failed to register misc char file note\n", | |
332 | __func__); | |
333 | ||
334 | return ret; | |
335 | } | |
336 | module_init(efi_capsule_loader_init); | |
337 | ||
338 | static void __exit efi_capsule_loader_exit(void) | |
339 | { | |
340 | misc_deregister(&efi_capsule_misc); | |
341 | } | |
342 | module_exit(efi_capsule_loader_exit); | |
343 | ||
344 | MODULE_DESCRIPTION("EFI capsule firmware binary loader"); | |
345 | MODULE_LICENSE("GPL v2"); |