summaryrefslogtreecommitdiffstats
path: root/drivers/firmware/efi/capsule-loader.c
blob: ec8ac5c4dd84f93e386db9871946c81ea1dbc8d5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
/*
 * EFI capsule loader driver.
 *
 * Copyright 2015 Intel Corporation
 *
 * This file is part of the Linux kernel, and is made available under
 * the terms of the GNU General Public License version 2.
 */

#define pr_fmt(fmt) "efi: " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/miscdevice.h>
#include <linux/highmem.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/efi.h>
#include <linux/vmalloc.h>

#define NO_FURTHER_WRITE_ACTION -1

#ifndef phys_to_page
#define phys_to_page(x)		pfn_to_page((x) >> PAGE_SHIFT)
#endif

/**
 * efi_free_all_buff_pages - free all previous allocated buffer pages
 * @cap_info: pointer to current instance of capsule_info structure
 *
 *	In addition to freeing buffer pages, it flags NO_FURTHER_WRITE_ACTION
 *	to cease processing data in subsequent write(2) calls until close(2)
 *	is called.
 **/
static void efi_free_all_buff_pages(struct capsule_info *cap_info)
{
	while (cap_info->index > 0)
		__free_page(phys_to_page(cap_info->pages[--cap_info->index]));

	cap_info->index = NO_FURTHER_WRITE_ACTION;
}

int __efi_capsule_setup_info(struct capsule_info *cap_info)
{
	size_t pages_needed;
	int ret;
	void *temp_page;

	pages_needed = ALIGN(cap_info->total_size, PAGE_SIZE) / PAGE_SIZE;

	if (pages_needed == 0) {
		pr_err("invalid capsule size");
		return -EINVAL;
	}

	/* Check if the capsule binary supported */
	ret = efi_capsule_supported(cap_info->header.guid,
				    cap_info->header.flags,
				    cap_info->header.imagesize,
				    &cap_info->reset_type);
	if (ret) {
		pr_err("capsule not supported\n");
		return ret;
	}

	temp_page = krealloc(cap_info->pages,
			     pages_needed * sizeof(void *),
			     GFP_KERNEL | __GFP_ZERO);
	if (!temp_page)
		return -ENOMEM;

	cap_info->pages = temp_page;

	return 0;
}

/**
 * efi_capsule_setup_info - obtain the efi capsule header in the binary and
 *			    setup capsule_info structure
 * @cap_info: pointer to current instance of capsule_info structure
 * @kbuff: a mapped first page buffer pointer
 * @hdr_bytes: the total received number of bytes for efi header
 *
 * Platforms with non-standard capsule update mechanisms can override
 * this __weak function so they can perform any required capsule
 * image munging. See quark_quirk_function() for an example.
 **/
int __weak efi_capsule_setup_info(struct capsule_info *cap_info, void *kbuff,
				  size_t hdr_bytes)
{
	/* Only process data block that is larger than efi header size */
	if (hdr_bytes < sizeof(efi_capsule_header_t))
		return 0;

	memcpy(&cap_info->header, kbuff, sizeof(cap_info->header));
	cap_info->total_size = cap_info->header.imagesize;

	return __efi_capsule_setup_info(cap_info);
}

/**
 * efi_capsule_submit_update - invoke the efi_capsule_update API once binary
 *			       upload done
 * @cap_info: pointer to current instance of capsule_info structure
 **/
static ssize_t efi_capsule_submit_update(struct capsule_info *cap_info)
{
	int ret;

	ret = efi_capsule_update(&cap_info->header, cap_info->pages);
	if (ret) {
		pr_err("capsule update failed\n");
		return ret;
	}

	/* Indicate capsule binary uploading is done */
	cap_info->index = NO_FURTHER_WRITE_ACTION;
	pr_info("Successfully upload capsule file with reboot type '%s'\n",
		!cap_info->reset_type ? "RESET_COLD" :
		cap_info->reset_type == 1 ? "RESET_WARM" :
		"RESET_SHUTDOWN");
	return 0;
}

/**
 * efi_capsule_write - store the capsule binary and pass it to
 *		       efi_capsule_update() API
 * @file: file pointer
 * @buff: buffer pointer
 * @count: number of bytes in @buff
 * @offp: not used
 *
 *	Expectation:
 *	- A user space tool should start at the beginning of capsule binary and
 *	  pass data in sequentially.
 *	- Users should close and re-open this file note in order to upload more
 *	  capsules.
 *	- After an error returned, user should close the file and restart the
 *	  operation for the next try otherwise -EIO will be returned until the
 *	  file is closed.
 *	- An EFI capsule header must be located at the beginning of capsule
 *	  binary file and passed in as first block data of write operation.
 **/
static ssize_t efi_capsule_write(struct file *file, const char __user *buff,
				 size_t count, loff_t *offp)
{
	int ret = 0;
	struct capsule_info *cap_info = file->private_data;
	struct page *page;
	void *kbuff = NULL;
	size_t write_byte;

	if (count == 0)
		return 0;

	/* Return error while NO_FURTHER_WRITE_ACTION is flagged */
	if (cap_info->index < 0)
		return -EIO;

	/* Only alloc a new page when previous page is full */
	if (!cap_info->page_bytes_remain) {
		page = alloc_page(GFP_KERNEL);
		if (!page) {
			ret = -ENOMEM;
			goto failed;
		}

		cap_info->pages[cap_info->index++] = page_to_phys(page);
		cap_info->page_bytes_remain = PAGE_SIZE;
	} else {
		page = phys_to_page(cap_info->pages[cap_info->index - 1]);
	}

	kbuff = kmap(page);
	kbuff += PAGE_SIZE - cap_info->page_bytes_remain;

	/* Copy capsule binary data from user space to kernel space buffer */
	write_byte = min_t(size_t, count, cap_info->page_bytes_remain);
	if (copy_from_user(kbuff, buff, write_byte)) {
		ret = -EFAULT;
		goto fail_unmap;
	}
	cap_info->page_bytes_remain -= write_byte;

	/* Setup capsule binary info structure */
	if (cap_info->header.headersize == 0) {
		ret = efi_capsule_setup_info(cap_info, kbuff - cap_info->count,
					     cap_info->count + write_byte);
		if (ret)
			goto fail_unmap;
	}

	cap_info->count += write_byte;
	kunmap(page);

	/* Submit the full binary to efi_capsule_update() API */
	if (cap_info->header.headersize > 0 &&
	    cap_info->count >= cap_info->total_size) {
		if (cap_info->count > cap_info->total_size) {
			pr_err("capsule upload size exceeded header defined size\n");
			ret = -EINVAL;
			goto failed;
		}

		ret = efi_capsule_submit_update(cap_info);
		if (ret)
			goto failed;
	}

	return write_byte;

fail_unmap:
	kunmap(page);
failed:
	efi_free_all_buff_pages(cap_info);
	return ret;
}

/**
 * efi_capsule_flush - called by file close or file flush
 * @file: file pointer
 * @id: not used
 *
 *	If a capsule is being partially uploaded then calling this function
 *	will be treated as upload termination and will free those completed
 *	buffer pages and -ECANCELED will be returned.
 **/
static int efi_capsule_flush(struct file *file, fl_owner_t id)
{
	int ret = 0;
	struct capsule_info *cap_info = file->private_data;

	if (cap_info->index > 0) {
		pr_err("capsule upload not complete\n");
		efi_free_all_buff_pages(cap_info);
		ret = -ECANCELED;
	}

	return ret;
}

/**
 * efi_capsule_release - called by file close
 * @inode: not used
 * @file: file pointer
 *
 *	We will not free successfully submitted pages since efi update
 *	requires data to be maintained across system reboot.
 **/
static int efi_capsule_release(struct inode *inode, struct file *file)
{
	struct capsule_info *cap_info = file->private_data;

	kfree(cap_info->pages);
	kfree(file->private_data);
	file->private_data = NULL;
	return 0;
}

/**
 * efi_capsule_open - called by file open
 * @inode: not used
 * @file: file pointer
 *
 *	Will allocate each capsule_info memory for each file open call.
 *	This provided the capability to support multiple file open feature
 *	where user is not needed to wait for others to finish in order to
 *	upload their capsule binary.
 **/
static int efi_capsule_open(struct inode *inode, struct file *file)
{
	struct capsule_info *cap_info;

	cap_info = kzalloc(sizeof(*cap_info), GFP_KERNEL);
	if (!cap_info)
		return -ENOMEM;

	cap_info->pages = kzalloc(sizeof(void *), GFP_KERNEL);
	if (!cap_info->pages) {
		kfree(cap_info);
		return -ENOMEM;
	}

	file->private_data = cap_info;

	return 0;
}

static const struct file_operations efi_capsule_fops = {
	.owner = THIS_MODULE,
	.open = efi_capsule_open,
	.write = efi_capsule_write,
	.flush = efi_capsule_flush,
	.release = efi_capsule_release,
	.llseek = no_llseek,
};

static struct miscdevice efi_capsule_misc = {
	.minor = MISC_DYNAMIC_MINOR,
	.name = "efi_capsule_loader",
	.fops = &efi_capsule_fops,
};

static int __init efi_capsule_loader_init(void)
{
	int ret;

	if (!efi_enabled(EFI_RUNTIME_SERVICES))
		return -ENODEV;

	ret = misc_register(&efi_capsule_misc);
	if (ret)
		pr_err("Unable to register capsule loader device\n");

	return ret;
}
module_init(efi_capsule_loader_init);

static void __exit efi_capsule_loader_exit(void)
{
	misc_deregister(&efi_capsule_misc);
}
module_exit(efi_capsule_loader_exit);

MODULE_DESCRIPTION("EFI capsule firmware binary loader");
MODULE_LICENSE("GPL v2");