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
22static bool dump_properties __initdata;
23
24static 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
32struct 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
42struct properties_header {
43	u32 len;
44	u32 version;
45	u32 dev_count;
46	struct dev_header dev_header[];
47};
48
49static 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
118static 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 = kcalloc(dev_header->prop_count + 1, sizeof(*entry),
150				GFP_KERNEL);
151		if (!entry) {
152			dev_err(dev, "cannot allocate properties\n");
153			goto skip_device;
154		}
155
156		unmarshal_key_value_pairs(dev_header, dev, ptr, entry);
157		if (!entry[0].name)
158			goto skip_device;
159
160		ret = device_create_managed_software_node(dev, entry, NULL);
161		if (ret)
162			dev_err(dev, "error %d assigning properties\n", ret);
163
164		for (i = 0; entry[i].name; i++)
165			kfree(entry[i].name);
166
167skip_device:
168		kfree(entry);
169		put_device(dev);
170		offset += dev_header->len;
171	}
172
173	return 0;
174}
175
176static int __init map_properties(void)
177{
178	struct properties_header *properties;
179	struct setup_data *data;
180	u32 data_len;
181	u64 pa_data;
182	int ret;
183
184	if (!x86_apple_machine)
185		return 0;
186
187	pa_data = boot_params.hdr.setup_data;
188	while (pa_data) {
189		data = memremap(pa_data, sizeof(*data), MEMREMAP_WB);
190		if (!data) {
191			pr_err("cannot map setup_data header\n");
192			return -ENOMEM;
193		}
194
195		if (data->type != SETUP_APPLE_PROPERTIES) {
196			pa_data = data->next;
197			memunmap(data);
198			continue;
199		}
200
201		data_len = data->len;
202		memunmap(data);
203
204		data = memremap(pa_data, sizeof(*data) + data_len, MEMREMAP_WB);
205		if (!data) {
206			pr_err("cannot map setup_data payload\n");
207			return -ENOMEM;
208		}
209
210		properties = (struct properties_header *)data->data;
211		if (properties->version != 1) {
212			pr_err("unsupported version:\n");
213			print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
214			       16, 1, properties, data_len, true);
215			ret = -ENOTSUPP;
216		} else if (properties->len != data_len) {
217			pr_err("length mismatch, expected %u\n", data_len);
218			print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
219			       16, 1, properties, data_len, true);
220			ret = -EINVAL;
221		} else
222			ret = unmarshal_devices(properties);
223
224		/*
225		 * Can only free the setup_data payload but not its header
226		 * to avoid breaking the chain of ->next pointers.
227		 */
228		data->len = 0;
229		memunmap(data);
230		memblock_free_late(pa_data + sizeof(*data), data_len);
231
232		return ret;
233	}
234	return 0;
235}
236
237fs_initcall(map_properties);
238