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 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 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 } 117 118 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 = 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); 166 167 skip_device: 168 kfree(entry); 169 put_device(dev); 170 offset += dev_header->len; 171 } 172 173 return 0; 174 } 175 176 static 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 } 236 237 fs_initcall(map_properties); 238