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  **/
efi_free_all_buff_pages(struct capsule_info * cap_info)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 
__efi_capsule_setup_info(struct capsule_info * cap_info)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  **/
efi_capsule_setup_info(struct capsule_info * cap_info,void * kbuff,size_t hdr_bytes)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  **/
efi_capsule_submit_update(struct capsule_info * cap_info)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  **/
efi_capsule_write(struct file * file,const char __user * buff,size_t count,loff_t * offp)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  **/
efi_capsule_release(struct inode * inode,struct file * file)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  **/
efi_capsule_open(struct inode * inode,struct file * file)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 	.llseek = no_llseek,
313 };
314 
315 static struct miscdevice efi_capsule_misc = {
316 	.minor = MISC_DYNAMIC_MINOR,
317 	.name = "efi_capsule_loader",
318 	.fops = &efi_capsule_fops,
319 };
320 
efi_capsule_loader_init(void)321 static int __init efi_capsule_loader_init(void)
322 {
323 	int ret;
324 
325 	if (!efi_enabled(EFI_RUNTIME_SERVICES))
326 		return -ENODEV;
327 
328 	ret = misc_register(&efi_capsule_misc);
329 	if (ret)
330 		pr_err("Unable to register capsule loader device\n");
331 
332 	return ret;
333 }
334 module_init(efi_capsule_loader_init);
335 
efi_capsule_loader_exit(void)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");
344