aboutsummaryrefslogtreecommitdiff
path: root/drivers/firmware/efi/apple-properties.c
blob: 2b675f788b61d8eab47e128c4d8fd8409af19d21 (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
/*
 * apple-properties.c - EFI device properties on Macs
 * Copyright (C) 2016 Lukas Wunner <lukas@wunner.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License (version 2) as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that 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/>.
 *
 * Note, all properties are considered as u8 arrays.
 * To get a value of any of them the caller must use device_property_read_u8_array().
 */

#define pr_fmt(fmt) "apple-properties: " fmt

#include <linux/bootmem.h>
#include <linux/efi.h>
#include <linux/io.h>
#include <linux/platform_data/x86/apple.h>
#include <linux/property.h>
#include <linux/slab.h>
#include <linux/ucs2_string.h>
#include <asm/setup.h>

static bool dump_properties __initdata;

static int __init dump_properties_enable(char *arg)
{
	dump_properties = true;
	return 0;
}

__setup("dump_apple_properties", dump_properties_enable);

struct dev_header {
	u32 len;
	u32 prop_count;
	struct efi_dev_path path[0];
	/*
	 * followed by key/value pairs, each key and value preceded by u32 len,
	 * len includes itself, value may be empty (in which case its len is 4)
	 */
};

struct properties_header {
	u32 len;
	u32 version;
	u32 dev_count;
	struct dev_header dev_header[0];
};

static void __init unmarshal_key_value_pairs(struct dev_header *dev_header,
					     struct device *dev, void *ptr,
					     struct property_entry entry[])
{
	int i;

	for (i = 0; i < dev_header->prop_count; i++) {
		int remaining = dev_header->len - (ptr - (void *)dev_header);
		u32 key_len, val_len;
		char *key;

		if (sizeof(key_len) > remaining)
			break;

		key_len = *(typeof(key_len) *)ptr;
		if (key_len + sizeof(val_len) > remaining ||
		    key_len < sizeof(key_len) + sizeof(efi_char16_t) ||
		    *(efi_char16_t *)(ptr + sizeof(key_len)) == 0) {
			dev_err(dev, "invalid property name len at %#zx\n",
				ptr - (void *)dev_header);
			break;
		}

		val_len = *(typeof(val_len) *)(ptr + key_len);
		if (key_len + val_len > remaining ||
		    val_len < sizeof(val_len)) {
			dev_err(dev, "invalid property val len at %#zx\n",
				ptr - (void *)dev_header + key_len);
			break;
		}

		/* 4 bytes to accommodate UTF-8 code points + null byte */
		key = kzalloc((key_len - sizeof(key_len)) * 4 + 1, GFP_KERNEL);
		if (!key) {
			dev_err(dev, "cannot allocate property name\n");
			break;
		}
		ucs2_as_utf8(key, ptr + sizeof(key_len),
			     key_len - sizeof(key_len));

		entry[i].name = key;
		entry[i].length = val_len - sizeof(val_len);
		entry[i].is_array = !!entry[i].length;
		entry[i].type = DEV_PROP_U8;
		entry[i].pointer.u8_data = ptr + key_len + sizeof(val_len);

		if (dump_properties) {
			dev_info(dev, "property: %s\n", entry[i].name);
			print_hex_dump(KERN_INFO, pr_fmt(), DUMP_PREFIX_OFFSET,
				16, 1, entry[i].pointer.u8_data,
				entry[i].length, true);
		}

		ptr += key_len + val_len;
	}

	if (i != dev_header->prop_count) {
		dev_err(dev, "got %d device properties, expected %u\n", i,
			dev_header->prop_count);
		print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
			16, 1, dev_header, dev_header->len, true);
		return;
	}

	dev_info(dev, "assigning %d device properties\n", i);
}

static int __init unmarshal_devices(struct properties_header *properties)
{
	size_t offset = offsetof(struct properties_header, dev_header[0]);

	while (offset + sizeof(struct dev_header) < properties->len) {
		struct dev_header *dev_header = (void *)properties + offset;
		struct property_entry *entry = NULL;
		struct device *dev;
		size_t len;
		int ret, i;
		void *ptr;

		if (offset + dev_header->len > properties->len ||
		    dev_header->len <= sizeof(*dev_header)) {
			pr_err("invalid len in dev_header at %#zx\n", offset);
			return -EINVAL;
		}

		ptr = dev_header->path;
		len = dev_header->len - sizeof(*dev_header);

		dev = efi_get_device_by_path((struct efi_dev_path **)&ptr, &len);
		if (IS_ERR(dev)) {
			pr_err("device path parse error %ld at %#zx:\n",
			       PTR_ERR(dev), ptr - (void *)dev_header);
			print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
			       16, 1, dev_header, dev_header->len, true);
			dev = NULL;
			goto skip_device;
		}

		entry = kcalloc(dev_header->prop_count + 1, sizeof(*entry),
				GFP_KERNEL);
		if (!entry) {
			dev_err(dev, "cannot allocate properties\n");
			goto skip_device;
		}

		unmarshal_key_value_pairs(dev_header, dev, ptr, entry);
		if (!entry[0].name)
			goto skip_device;

		ret = device_add_properties(dev, entry); /* makes deep copy */
		if (ret)
			dev_err(dev, "error %d assigning properties\n", ret);

		for (i = 0; entry[i].name; i++)
			kfree(entry[i].name);

skip_device:
		kfree(entry);
		put_device(dev);
		offset += dev_header->len;
	}

	return 0;
}

static int __init map_properties(void)
{
	struct properties_header *properties;
	struct setup_data *data;
	u32 data_len;
	u64 pa_data;
	int ret;

	if (!x86_apple_machine)
		return 0;

	pa_data = boot_params.hdr.setup_data;
	while (pa_data) {
		data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
		if (!data) {
			pr_err("cannot map setup_data header\n");
			return -ENOMEM;
		}

		if (data->type != SETUP_APPLE_PROPERTIES) {
			pa_data = data->next;
			memunmap(data);
			continue;
		}

		data_len = data->len;
		memunmap(data);

		data = memremap(pa_data, sizeof(*data) + data_len, MEMREMAP_WB);
		if (!data) {
			pr_err("cannot map setup_data payload\n");
			return -ENOMEM;
		}

		properties = (struct properties_header *)data->data;
		if (properties->version != 1) {
			pr_err("unsupported version:\n");
			print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
			       16, 1, properties, data_len, true);
			ret = -ENOTSUPP;
		} else if (properties->len != data_len) {
			pr_err("length mismatch, expected %u\n", data_len);
			print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
			       16, 1, properties, data_len, true);
			ret = -EINVAL;
		} else
			ret = unmarshal_devices(properties);

		/*
		 * Can only free the setup_data payload but not its header
		 * to avoid breaking the chain of ->next pointers.
		 */
		data->len = 0;
		memunmap(data);
		memblock_free_late(pa_data + sizeof(*data), data_len);

		return ret;
	}
	return 0;
}

fs_initcall(map_properties);