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 **/
30static 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
38int __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 **/
91int __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 **/
109static 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 **/
168static 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
238fail_unmap:
239	kunmap(page);
240failed:
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 **/
253static 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 **/
281static 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
307static 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
315static struct miscdevice efi_capsule_misc = {
316	.minor = MISC_DYNAMIC_MINOR,
317	.name = "efi_capsule_loader",
318	.fops = &efi_capsule_fops,
319};
320
321static 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}
334module_init(efi_capsule_loader_init);
335
336static void __exit efi_capsule_loader_exit(void)
337{
338	misc_deregister(&efi_capsule_misc);
339}
340module_exit(efi_capsule_loader_exit);
341
342MODULE_DESCRIPTION("EFI capsule firmware binary loader");
343MODULE_LICENSE("GPL v2");
344