aboutsummaryrefslogtreecommitdiff
path: root/drivers/firmware/efi/fake_mem.c
blob: 446c669431c077838241b2d9367aee371530cdc8 (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
/*
 * fake_mem.c
 *
 * Copyright (C) 2015 FUJITSU LIMITED
 * Author: Taku Izumi <izumi.taku@jp.fujitsu.com>
 *
 * This code introduces new boot option named "efi_fake_mem"
 * By specifying this parameter, you can add arbitrary attribute to
 * specific memory range by updating original (firmware provided) EFI
 * memmap.
 *
 *  This program is free software; you can redistribute it and/or modify it
 *  under the terms and conditions of the GNU General Public License,
 *  version 2, as published by the Free Software Foundation.
 *
 *  This program is distributed in the hope it will be useful, but WITHOUT
 *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 *  more details.
 *
 *  You should have received a copy of the GNU General Public License along with
 *  this program; if not, see <http://www.gnu.org/licenses/>.
 *
 *  The full GNU General Public License is included in this distribution in
 *  the file called "COPYING".
 */

#include <linux/kernel.h>
#include <linux/efi.h>
#include <linux/init.h>
#include <linux/memblock.h>
#include <linux/types.h>
#include <linux/sort.h>
#include <asm/efi.h>

#define EFI_MAX_FAKEMEM CONFIG_EFI_MAX_FAKE_MEM

struct fake_mem {
	struct range range;
	u64 attribute;
};
static struct fake_mem fake_mems[EFI_MAX_FAKEMEM];
static int nr_fake_mem;

static int __init cmp_fake_mem(const void *x1, const void *x2)
{
	const struct fake_mem *m1 = x1;
	const struct fake_mem *m2 = x2;

	if (m1->range.start < m2->range.start)
		return -1;
	if (m1->range.start > m2->range.start)
		return 1;
	return 0;
}

/**
 * efi_fake_memmap_split_count - Count number of additional EFI memmap entries
 * @md: EFI memory descriptor to split
 * @range: Address range (start, end) to split around
 *
 * Returns the number of additional EFI memmap entries required to
 * accomodate @range.
 */
static int efi_fake_memmap_split_count(efi_memory_desc_t *md, struct range *range)
{
	u64 m_start, m_end;
	u64 start, end;
	int count = 0;

	start = md->phys_addr;
	end = start + (md->num_pages << EFI_PAGE_SHIFT) - 1;

	/* modifying range */
	m_start = range->start;
	m_end = range->end;

	if (m_start <= start) {
		/* split into 2 parts */
		if (start < m_end && m_end < end)
			count++;
	}

	if (start < m_start && m_start < end) {
		/* split into 3 parts */
		if (m_end < end)
			count += 2;
		/* split into 2 parts */
		if (end <= m_end)
			count++;
	}

	return count;
}

/**
 * efi_fake_memmap_insert - Insert a fake memory region in an EFI memmap
 * @old_memmap: The existing EFI memory map structure
 * @buf: Address of buffer to store new map
 * @mem: Fake memory map entry to insert
 *
 * It is suggested that you call efi_fake_memmap_split_count() first
 * to see how large @buf needs to be.
 */
static void efi_fake_memmap_insert(struct efi_memory_map *old_memmap,
				   void *buf, struct fake_mem *mem)
{
	u64 m_start, m_end, m_attr;
	efi_memory_desc_t *md;
	u64 start, end;
	void *old, *new;

	/* modifying range */
	m_start = mem->range.start;
	m_end = mem->range.end;
	m_attr = mem->attribute;

	for (old = old_memmap->map, new = buf;
	     old < old_memmap->map_end;
	     old += old_memmap->desc_size, new += old_memmap->desc_size) {

		/* copy original EFI memory descriptor */
		memcpy(new, old, old_memmap->desc_size);
		md = new;
		start = md->phys_addr;
		end = md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT) - 1;

		if (m_start <= start && end <= m_end)
			md->attribute |= m_attr;

		if (m_start <= start &&
		    (start < m_end && m_end < end)) {
			/* first part */
			md->attribute |= m_attr;
			md->num_pages = (m_end - md->phys_addr + 1) >>
				EFI_PAGE_SHIFT;
			/* latter part */
			new += old_memmap->desc_size;
			memcpy(new, old, old_memmap->desc_size);
			md = new;
			md->phys_addr = m_end + 1;
			md->num_pages = (end - md->phys_addr + 1) >>
				EFI_PAGE_SHIFT;
		}

		if ((start < m_start && m_start < end) && m_end < end) {
			/* first part */
			md->num_pages = (m_start - md->phys_addr) >>
				EFI_PAGE_SHIFT;
			/* middle part */
			new += old_memmap->desc_size;
			memcpy(new, old, old_memmap->desc_size);
			md = new;
			md->attribute |= m_attr;
			md->phys_addr = m_start;
			md->num_pages = (m_end - m_start + 1) >>
				EFI_PAGE_SHIFT;
			/* last part */
			new += old_memmap->desc_size;
			memcpy(new, old, old_memmap->desc_size);
			md = new;
			md->phys_addr = m_end + 1;
			md->num_pages = (end - m_end) >>
				EFI_PAGE_SHIFT;
		}

		if ((start < m_start && m_start < end) &&
		    (end <= m_end)) {
			/* first part */
			md->num_pages = (m_start - md->phys_addr) >>
				EFI_PAGE_SHIFT;
			/* latter part */
			new += old_memmap->desc_size;
			memcpy(new, old, old_memmap->desc_size);
			md = new;
			md->phys_addr = m_start;
			md->num_pages = (end - md->phys_addr + 1) >>
				EFI_PAGE_SHIFT;
			md->attribute |= m_attr;
		}
	}
}

void __init efi_fake_memmap(void)
{
	struct efi_memory_map_data data;
	int new_nr_map = efi.memmap.nr_map;
	efi_memory_desc_t *md;
	phys_addr_t new_memmap_phy;
	void *new_memmap;
	int i;

	if (!nr_fake_mem)
		return;

	/* count up the number of EFI memory descriptor */
	for (i = 0; i < nr_fake_mem; i++) {
		for_each_efi_memory_desc(md) {
			struct range *r = &fake_mems[i].range;

			new_nr_map += efi_fake_memmap_split_count(md, r);
		}
	}

	/* allocate memory for new EFI memmap */
	new_memmap_phy = memblock_alloc(efi.memmap.desc_size * new_nr_map,
					PAGE_SIZE);
	if (!new_memmap_phy)
		return;

	/* create new EFI memmap */
	new_memmap = early_memremap(new_memmap_phy,
				    efi.memmap.desc_size * new_nr_map);
	if (!new_memmap) {
		memblock_free(new_memmap_phy, efi.memmap.desc_size * new_nr_map);
		return;
	}

	for (i = 0; i < nr_fake_mem; i++)
		efi_fake_memmap_insert(&efi.memmap, new_memmap, &fake_mems[i]);

	/* swap into new EFI memmap */
	early_memunmap(new_memmap, efi.memmap.desc_size * new_nr_map);
	efi_memmap_unmap();

	data.phys_map = new_memmap_phy;
	data.size = efi.memmap.desc_size * new_nr_map;
	data.desc_version = efi.memmap.desc_version;
	data.desc_size = efi.memmap.desc_size;
	efi_memmap_init_early(&data);

	/* print new EFI memmap */
	efi_print_memmap();
}

static int __init setup_fake_mem(char *p)
{
	u64 start = 0, mem_size = 0, attribute = 0;
	int i;

	if (!p)
		return -EINVAL;

	while (*p != '\0') {
		mem_size = memparse(p, &p);
		if (*p == '@')
			start = memparse(p+1, &p);
		else
			break;

		if (*p == ':')
			attribute = simple_strtoull(p+1, &p, 0);
		else
			break;

		if (nr_fake_mem >= EFI_MAX_FAKEMEM)
			break;

		fake_mems[nr_fake_mem].range.start = start;
		fake_mems[nr_fake_mem].range.end = start + mem_size - 1;
		fake_mems[nr_fake_mem].attribute = attribute;
		nr_fake_mem++;

		if (*p == ',')
			p++;
	}

	sort(fake_mems, nr_fake_mem, sizeof(struct fake_mem),
	     cmp_fake_mem, NULL);

	for (i = 0; i < nr_fake_mem; i++)
		pr_info("efi_fake_mem: add attr=0x%016llx to [mem 0x%016llx-0x%016llx]",
			fake_mems[i].attribute, fake_mems[i].range.start,
			fake_mems[i].range.end);

	return *p == '\0' ? 0 : -EINVAL;
}

early_param("efi_fake_mem", setup_fake_mem);