1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * apple-properties.c - EFI device properties on Macs
4 * Copyright (C) 2016 Lukas Wunner <lukas@wunner.de>
5 *
6 * Properties are stored either as:
7 * u8 arrays which can be retrieved with device_property_read_u8_array() or
8 * booleans which can be queried with device_property_present().
9 */
10
11 #define pr_fmt(fmt) "apple-properties: " fmt
12
13 #include <linux/memblock.h>
14 #include <linux/efi.h>
15 #include <linux/io.h>
16 #include <linux/platform_data/x86/apple.h>
17 #include <linux/property.h>
18 #include <linux/slab.h>
19 #include <linux/ucs2_string.h>
20 #include <asm/setup.h>
21
22 static bool dump_properties __initdata;
23
dump_properties_enable(char * arg)24 static int __init dump_properties_enable(char *arg)
25 {
26 dump_properties = true;
27 return 1;
28 }
29
30 __setup("dump_apple_properties", dump_properties_enable);
31
32 struct dev_header {
33 u32 len;
34 u32 prop_count;
35 struct efi_dev_path path[];
36 /*
37 * followed by key/value pairs, each key and value preceded by u32 len,
38 * len includes itself, value may be empty (in which case its len is 4)
39 */
40 };
41
42 struct properties_header {
43 u32 len;
44 u32 version;
45 u32 dev_count;
46 struct dev_header dev_header[];
47 };
48
unmarshal_key_value_pairs(struct dev_header * dev_header,struct device * dev,const void * ptr,struct property_entry entry[])49 static void __init unmarshal_key_value_pairs(struct dev_header *dev_header,
50 struct device *dev, const void *ptr,
51 struct property_entry entry[])
52 {
53 int i;
54
55 for (i = 0; i < dev_header->prop_count; i++) {
56 int remaining = dev_header->len - (ptr - (void *)dev_header);
57 u32 key_len, val_len, entry_len;
58 const u8 *entry_data;
59 char *key;
60
61 if (sizeof(key_len) > remaining)
62 break;
63
64 key_len = *(typeof(key_len) *)ptr;
65 if (key_len + sizeof(val_len) > remaining ||
66 key_len < sizeof(key_len) + sizeof(efi_char16_t) ||
67 *(efi_char16_t *)(ptr + sizeof(key_len)) == 0) {
68 dev_err(dev, "invalid property name len at %#zx\n",
69 ptr - (void *)dev_header);
70 break;
71 }
72
73 val_len = *(typeof(val_len) *)(ptr + key_len);
74 if (key_len + val_len > remaining ||
75 val_len < sizeof(val_len)) {
76 dev_err(dev, "invalid property val len at %#zx\n",
77 ptr - (void *)dev_header + key_len);
78 break;
79 }
80
81 /* 4 bytes to accommodate UTF-8 code points + null byte */
82 key = kzalloc((key_len - sizeof(key_len)) * 4 + 1, GFP_KERNEL);
83 if (!key) {
84 dev_err(dev, "cannot allocate property name\n");
85 break;
86 }
87 ucs2_as_utf8(key, ptr + sizeof(key_len),
88 key_len - sizeof(key_len));
89
90 entry_data = ptr + key_len + sizeof(val_len);
91 entry_len = val_len - sizeof(val_len);
92 if (entry_len)
93 entry[i] = PROPERTY_ENTRY_U8_ARRAY_LEN(key, entry_data,
94 entry_len);
95 else
96 entry[i] = PROPERTY_ENTRY_BOOL(key);
97
98 if (dump_properties) {
99 dev_info(dev, "property: %s\n", key);
100 print_hex_dump(KERN_INFO, pr_fmt(), DUMP_PREFIX_OFFSET,
101 16, 1, entry_data, entry_len, true);
102 }
103
104 ptr += key_len + val_len;
105 }
106
107 if (i != dev_header->prop_count) {
108 dev_err(dev, "got %d device properties, expected %u\n", i,
109 dev_header->prop_count);
110 print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
111 16, 1, dev_header, dev_header->len, true);
112 return;
113 }
114
115 dev_info(dev, "assigning %d device properties\n", i);
116 }
117
unmarshal_devices(struct properties_header * properties)118 static int __init unmarshal_devices(struct properties_header *properties)
119 {
120 size_t offset = offsetof(struct properties_header, dev_header[0]);
121
122 while (offset + sizeof(struct dev_header) < properties->len) {
123 struct dev_header *dev_header = (void *)properties + offset;
124 struct property_entry *entry = NULL;
125 const struct efi_dev_path *ptr;
126 struct device *dev;
127 size_t len;
128 int ret, i;
129
130 if (offset + dev_header->len > properties->len ||
131 dev_header->len <= sizeof(*dev_header)) {
132 pr_err("invalid len in dev_header at %#zx\n", offset);
133 return -EINVAL;
134 }
135
136 ptr = dev_header->path;
137 len = dev_header->len - sizeof(*dev_header);
138
139 dev = efi_get_device_by_path(&ptr, &len);
140 if (IS_ERR(dev)) {
141 pr_err("device path parse error %ld at %#zx:\n",
142 PTR_ERR(dev), (void *)ptr - (void *)dev_header);
143 print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
144 16, 1, dev_header, dev_header->len, true);
145 dev = NULL;
146 goto skip_device;
147 }
148
149 entry = kzalloc_objs(*entry, dev_header->prop_count + 1);
150 if (!entry) {
151 dev_err(dev, "cannot allocate properties\n");
152 goto skip_device;
153 }
154
155 unmarshal_key_value_pairs(dev_header, dev, ptr, entry);
156 if (!entry[0].name)
157 goto skip_device;
158
159 ret = device_create_managed_software_node(dev, entry, NULL);
160 if (ret)
161 dev_err(dev, "error %d assigning properties\n", ret);
162
163 for (i = 0; entry[i].name; i++)
164 kfree(entry[i].name);
165
166 skip_device:
167 kfree(entry);
168 put_device(dev);
169 offset += dev_header->len;
170 }
171
172 return 0;
173 }
174
map_properties(void)175 static int __init map_properties(void)
176 {
177 struct properties_header *properties;
178 struct setup_data *data;
179 u32 data_len;
180 u64 pa_data;
181 int ret;
182
183 if (!x86_apple_machine)
184 return 0;
185
186 pa_data = boot_params.hdr.setup_data;
187 while (pa_data) {
188 data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
189 if (!data) {
190 pr_err("cannot map setup_data header\n");
191 return -ENOMEM;
192 }
193
194 if (data->type != SETUP_APPLE_PROPERTIES) {
195 pa_data = data->next;
196 memunmap(data);
197 continue;
198 }
199
200 data_len = data->len;
201 memunmap(data);
202
203 data = memremap(pa_data, sizeof(*data) + data_len, MEMREMAP_WB);
204 if (!data) {
205 pr_err("cannot map setup_data payload\n");
206 return -ENOMEM;
207 }
208
209 properties = (struct properties_header *)data->data;
210 if (properties->version != 1) {
211 pr_err("unsupported version:\n");
212 print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
213 16, 1, properties, data_len, true);
214 ret = -ENOTSUPP;
215 } else if (properties->len != data_len) {
216 pr_err("length mismatch, expected %u\n", data_len);
217 print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
218 16, 1, properties, data_len, true);
219 ret = -EINVAL;
220 } else
221 ret = unmarshal_devices(properties);
222
223 /*
224 * Can only free the setup_data payload but not its header
225 * to avoid breaking the chain of ->next pointers.
226 */
227 data->len = 0;
228 memunmap(data);
229 memblock_free_late(pa_data + sizeof(*data), data_len);
230
231 return ret;
232 }
233 return 0;
234 }
235
236 fs_initcall(map_properties);
237