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_flush - called by file close or file flush
247 * @file: file pointer
248 * @id: not used
249 *
250 *	If a capsule is being partially uploaded then calling this function
251 *	will be treated as upload termination and will free those completed
252 *	buffer pages and -ECANCELED will be returned.
253 **/
254static int efi_capsule_flush(struct file *file, fl_owner_t id)
255{
256	int ret = 0;
257	struct capsule_info *cap_info = file->private_data;
258
259	if (cap_info->index > 0) {
260		pr_err("capsule upload not complete\n");
261		efi_free_all_buff_pages(cap_info);
262		ret = -ECANCELED;
263	}
264
265	return ret;
266}
267
268/**
269 * efi_capsule_release - called by file close
270 * @inode: not used
271 * @file: file pointer
272 *
273 *	We will not free successfully submitted pages since efi update
274 *	requires data to be maintained across system reboot.
275 **/
276static int efi_capsule_release(struct inode *inode, struct file *file)
277{
278	struct capsule_info *cap_info = file->private_data;
279
280	kfree(cap_info->pages);
281	kfree(cap_info->phys);
282	kfree(file->private_data);
283	file->private_data = NULL;
284	return 0;
285}
286
287/**
288 * efi_capsule_open - called by file open
289 * @inode: not used
290 * @file: file pointer
291 *
292 *	Will allocate each capsule_info memory for each file open call.
293 *	This provided the capability to support multiple file open feature
294 *	where user is not needed to wait for others to finish in order to
295 *	upload their capsule binary.
296 **/
297static int efi_capsule_open(struct inode *inode, struct file *file)
298{
299	struct capsule_info *cap_info;
300
301	cap_info = kzalloc(sizeof(*cap_info), GFP_KERNEL);
302	if (!cap_info)
303		return -ENOMEM;
304
305	cap_info->pages = kzalloc(sizeof(void *), GFP_KERNEL);
306	if (!cap_info->pages) {
307		kfree(cap_info);
308		return -ENOMEM;
309	}
310
311	cap_info->phys = kzalloc(sizeof(void *), GFP_KERNEL);
312	if (!cap_info->phys) {
313		kfree(cap_info->pages);
314		kfree(cap_info);
315		return -ENOMEM;
316	}
317
318	file->private_data = cap_info;
319
320	return 0;
321}
322
323static const struct file_operations efi_capsule_fops = {
324	.owner = THIS_MODULE,
325	.open = efi_capsule_open,
326	.write = efi_capsule_write,
327	.flush = efi_capsule_flush,
328	.release = efi_capsule_release,
329	.llseek = no_llseek,
330};
331
332static struct miscdevice efi_capsule_misc = {
333	.minor = MISC_DYNAMIC_MINOR,
334	.name = "efi_capsule_loader",
335	.fops = &efi_capsule_fops,
336};
337
338static int __init efi_capsule_loader_init(void)
339{
340	int ret;
341
342	if (!efi_enabled(EFI_RUNTIME_SERVICES))
343		return -ENODEV;
344
345	ret = misc_register(&efi_capsule_misc);
346	if (ret)
347		pr_err("Unable to register capsule loader device\n");
348
349	return ret;
350}
351module_init(efi_capsule_loader_init);
352
353static void __exit efi_capsule_loader_exit(void)
354{
355	misc_deregister(&efi_capsule_misc);
356}
357module_exit(efi_capsule_loader_exit);
358
359MODULE_DESCRIPTION("EFI capsule firmware binary loader");
360MODULE_LICENSE("GPL v2");