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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> | |
19 | ||
20 | #define NO_FURTHER_WRITE_ACTION -1 | |
21 | ||
22 | struct capsule_info { | |
23 | bool header_obtained; | |
24 | int reset_type; | |
25 | long index; | |
26 | size_t count; | |
27 | size_t total_size; | |
28 | struct page **pages; | |
29 | size_t page_bytes_remain; | |
30 | }; | |
31 | ||
32 | /** | |
33 | * efi_free_all_buff_pages - free all previous allocated buffer pages | |
34 | * @cap_info: pointer to current instance of capsule_info structure | |
35 | * | |
36 | * In addition to freeing buffer pages, it flags NO_FURTHER_WRITE_ACTION | |
37 | * to cease processing data in subsequent write(2) calls until close(2) | |
38 | * is called. | |
39 | **/ | |
40 | static void efi_free_all_buff_pages(struct capsule_info *cap_info) | |
41 | { | |
42 | while (cap_info->index > 0) | |
43 | __free_page(cap_info->pages[--cap_info->index]); | |
44 | ||
45 | cap_info->index = NO_FURTHER_WRITE_ACTION; | |
46 | } | |
47 | ||
48 | /** | |
49 | * efi_capsule_setup_info - obtain the efi capsule header in the binary and | |
50 | * setup capsule_info structure | |
51 | * @cap_info: pointer to current instance of capsule_info structure | |
52 | * @kbuff: a mapped first page buffer pointer | |
53 | * @hdr_bytes: the total received number of bytes for efi header | |
54 | **/ | |
55 | static ssize_t efi_capsule_setup_info(struct capsule_info *cap_info, | |
56 | void *kbuff, size_t hdr_bytes) | |
57 | { | |
58 | efi_capsule_header_t *cap_hdr; | |
59 | size_t pages_needed; | |
60 | int ret; | |
61 | void *temp_page; | |
62 | ||
63 | /* Only process data block that is larger than efi header size */ | |
64 | if (hdr_bytes < sizeof(efi_capsule_header_t)) | |
65 | return 0; | |
66 | ||
67 | /* Reset back to the correct offset of header */ | |
68 | cap_hdr = kbuff - cap_info->count; | |
69 | pages_needed = ALIGN(cap_hdr->imagesize, PAGE_SIZE) >> PAGE_SHIFT; | |
70 | ||
71 | if (pages_needed == 0) { | |
72 | pr_err("%s: pages count invalid\n", __func__); | |
73 | return -EINVAL; | |
74 | } | |
75 | ||
76 | /* Check if the capsule binary supported */ | |
77 | ret = efi_capsule_supported(cap_hdr->guid, cap_hdr->flags, | |
78 | cap_hdr->imagesize, | |
79 | &cap_info->reset_type); | |
80 | if (ret) { | |
81 | pr_err("%s: efi_capsule_supported() failed\n", | |
82 | __func__); | |
83 | return ret; | |
84 | } | |
85 | ||
86 | cap_info->total_size = cap_hdr->imagesize; | |
87 | temp_page = krealloc(cap_info->pages, | |
88 | pages_needed * sizeof(void *), | |
89 | GFP_KERNEL | __GFP_ZERO); | |
90 | if (!temp_page) { | |
91 | pr_debug("%s: krealloc() failed\n", __func__); | |
92 | return -ENOMEM; | |
93 | } | |
94 | ||
95 | cap_info->pages = temp_page; | |
96 | cap_info->header_obtained = true; | |
97 | ||
98 | return 0; | |
99 | } | |
100 | ||
101 | /** | |
102 | * efi_capsule_submit_update - invoke the efi_capsule_update API once binary | |
103 | * upload done | |
104 | * @cap_info: pointer to current instance of capsule_info structure | |
105 | **/ | |
106 | static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info) | |
107 | { | |
108 | int ret; | |
109 | void *cap_hdr_temp; | |
110 | ||
111 | cap_hdr_temp = kmap(cap_info->pages[0]); | |
112 | if (!cap_hdr_temp) { | |
113 | pr_debug("%s: kmap() failed\n", __func__); | |
114 | return -EFAULT; | |
115 | } | |
116 | ||
117 | ret = efi_capsule_update(cap_hdr_temp, cap_info->pages); | |
118 | kunmap(cap_info->pages[0]); | |
119 | if (ret) { | |
120 | pr_err("%s: efi_capsule_update() failed\n", __func__); | |
121 | return ret; | |
122 | } | |
123 | ||
124 | /* Indicate capsule binary uploading is done */ | |
125 | cap_info->index = NO_FURTHER_WRITE_ACTION; | |
126 | pr_info("%s: Successfully upload capsule file with reboot type '%s'\n", | |
127 | __func__, !cap_info->reset_type ? "RESET_COLD" : | |
128 | cap_info->reset_type == 1 ? "RESET_WARM" : | |
129 | "RESET_SHUTDOWN"); | |
130 | return 0; | |
131 | } | |
132 | ||
133 | /** | |
134 | * efi_capsule_write - store the capsule binary and pass it to | |
135 | * efi_capsule_update() API | |
136 | * @file: file pointer | |
137 | * @buff: buffer pointer | |
138 | * @count: number of bytes in @buff | |
139 | * @offp: not used | |
140 | * | |
141 | * Expectation: | |
142 | * - A user space tool should start at the beginning of capsule binary and | |
143 | * pass data in sequentially. | |
144 | * - Users should close and re-open this file note in order to upload more | |
145 | * capsules. | |
146 | * - After an error returned, user should close the file and restart the | |
147 | * operation for the next try otherwise -EIO will be returned until the | |
148 | * file is closed. | |
149 | * - An EFI capsule header must be located at the beginning of capsule | |
150 | * binary file and passed in as first block data of write operation. | |
151 | **/ | |
152 | static ssize_t efi_capsule_write(struct file *file, const char __user *buff, | |
153 | size_t count, loff_t *offp) | |
154 | { | |
155 | int ret = 0; | |
156 | struct capsule_info *cap_info = file->private_data; | |
157 | struct page *page; | |
158 | void *kbuff = NULL; | |
159 | size_t write_byte; | |
160 | ||
161 | if (count == 0) | |
162 | return 0; | |
163 | ||
164 | /* Return error while NO_FURTHER_WRITE_ACTION is flagged */ | |
165 | if (cap_info->index < 0) | |
166 | return -EIO; | |
167 | ||
168 | /* Only alloc a new page when previous page is full */ | |
169 | if (!cap_info->page_bytes_remain) { | |
170 | page = alloc_page(GFP_KERNEL); | |
171 | if (!page) { | |
172 | pr_debug("%s: alloc_page() failed\n", __func__); | |
173 | ret = -ENOMEM; | |
174 | goto failed; | |
175 | } | |
176 | ||
177 | cap_info->pages[cap_info->index++] = page; | |
178 | cap_info->page_bytes_remain = PAGE_SIZE; | |
179 | } | |
180 | ||
181 | page = cap_info->pages[cap_info->index - 1]; | |
182 | ||
183 | kbuff = kmap(page); | |
184 | if (!kbuff) { | |
185 | pr_debug("%s: kmap() failed\n", __func__); | |
186 | ret = -EFAULT; | |
187 | goto failed; | |
188 | } | |
189 | kbuff += PAGE_SIZE - cap_info->page_bytes_remain; | |
190 | ||
191 | /* Copy capsule binary data from user space to kernel space buffer */ | |
192 | write_byte = min_t(size_t, count, cap_info->page_bytes_remain); | |
193 | if (copy_from_user(kbuff, buff, write_byte)) { | |
194 | pr_debug("%s: copy_from_user() failed\n", __func__); | |
195 | ret = -EFAULT; | |
196 | goto fail_unmap; | |
197 | } | |
198 | cap_info->page_bytes_remain -= write_byte; | |
199 | ||
200 | /* Setup capsule binary info structure */ | |
201 | if (!cap_info->header_obtained) { | |
202 | ret = efi_capsule_setup_info(cap_info, kbuff, | |
203 | cap_info->count + write_byte); | |
204 | if (ret) | |
205 | goto fail_unmap; | |
206 | } | |
207 | ||
208 | cap_info->count += write_byte; | |
209 | kunmap(page); | |
210 | ||
211 | /* Submit the full binary to efi_capsule_update() API */ | |
212 | if (cap_info->header_obtained && | |
213 | cap_info->count >= cap_info->total_size) { | |
214 | if (cap_info->count > cap_info->total_size) { | |
215 | pr_err("%s: upload size exceeded header defined size\n", | |
216 | __func__); | |
217 | ret = -EINVAL; | |
218 | goto failed; | |
219 | } | |
220 | ||
221 | ret = efi_capsule_submit_update(cap_info); | |
222 | if (ret) | |
223 | goto failed; | |
224 | } | |
225 | ||
226 | return write_byte; | |
227 | ||
228 | fail_unmap: | |
229 | kunmap(page); | |
230 | failed: | |
231 | efi_free_all_buff_pages(cap_info); | |
232 | return ret; | |
233 | } | |
234 | ||
235 | /** | |
236 | * efi_capsule_flush - called by file close or file flush | |
237 | * @file: file pointer | |
238 | * @id: not used | |
239 | * | |
240 | * If a capsule is being partially uploaded then calling this function | |
241 | * will be treated as upload termination and will free those completed | |
242 | * buffer pages and -ECANCELED will be returned. | |
243 | **/ | |
244 | static int efi_capsule_flush(struct file *file, fl_owner_t id) | |
245 | { | |
246 | int ret = 0; | |
247 | struct capsule_info *cap_info = file->private_data; | |
248 | ||
249 | if (cap_info->index > 0) { | |
250 | pr_err("%s: capsule upload not complete\n", __func__); | |
251 | efi_free_all_buff_pages(cap_info); | |
252 | ret = -ECANCELED; | |
253 | } | |
254 | ||
255 | return ret; | |
256 | } | |
257 | ||
258 | /** | |
259 | * efi_capsule_release - called by file close | |
260 | * @inode: not used | |
261 | * @file: file pointer | |
262 | * | |
263 | * We will not free successfully submitted pages since efi update | |
264 | * requires data to be maintained across system reboot. | |
265 | **/ | |
266 | static int efi_capsule_release(struct inode *inode, struct file *file) | |
267 | { | |
268 | struct capsule_info *cap_info = file->private_data; | |
269 | ||
270 | kfree(cap_info->pages); | |
271 | kfree(file->private_data); | |
272 | file->private_data = NULL; | |
273 | return 0; | |
274 | } | |
275 | ||
276 | /** | |
277 | * efi_capsule_open - called by file open | |
278 | * @inode: not used | |
279 | * @file: file pointer | |
280 | * | |
281 | * Will allocate each capsule_info memory for each file open call. | |
282 | * This provided the capability to support multiple file open feature | |
283 | * where user is not needed to wait for others to finish in order to | |
284 | * upload their capsule binary. | |
285 | **/ | |
286 | static int efi_capsule_open(struct inode *inode, struct file *file) | |
287 | { | |
288 | struct capsule_info *cap_info; | |
289 | ||
290 | cap_info = kzalloc(sizeof(*cap_info), GFP_KERNEL); | |
291 | if (!cap_info) | |
292 | return -ENOMEM; | |
293 | ||
294 | cap_info->pages = kzalloc(sizeof(void *), GFP_KERNEL); | |
295 | if (!cap_info->pages) { | |
296 | kfree(cap_info); | |
297 | return -ENOMEM; | |
298 | } | |
299 | ||
300 | file->private_data = cap_info; | |
301 | ||
302 | return 0; | |
303 | } | |
304 | ||
305 | static const struct file_operations efi_capsule_fops = { | |
306 | .owner = THIS_MODULE, | |
307 | .open = efi_capsule_open, | |
308 | .write = efi_capsule_write, | |
309 | .flush = efi_capsule_flush, | |
310 | .release = efi_capsule_release, | |
311 | .llseek = no_llseek, | |
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("%s: Failed to register misc char file note\n", | |
330 | __func__); | |
331 | ||
332 | return ret; | |
333 | } | |
334 | module_init(efi_capsule_loader_init); | |
335 | ||
336 | static void __exit efi_capsule_loader_exit(void) | |
337 | { | |
338 | misc_deregister(&efi_capsule_misc); | |
339 | } | |
340 | module_exit(efi_capsule_loader_exit); | |
341 | ||
342 | MODULE_DESCRIPTION("EFI capsule firmware binary loader"); | |
343 | MODULE_LICENSE("GPL v2"); |