1 /* 2 * apple-properties.c - EFI device properties on Macs 3 * Copyright (C) 2016 Lukas Wunner <lukas@wunner.de> 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License (version 2) as 7 * published by the Free Software Foundation. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, see <http://www.gnu.org/licenses/>. 16 * 17 * Note, all properties are considered as u8 arrays. 18 * To get a value of any of them the caller must use device_property_read_u8_array(). 19 */ 20 21 #define pr_fmt(fmt) "apple-properties: " fmt 22 23 #include <linux/bootmem.h> 24 #include <linux/efi.h> 25 #include <linux/io.h> 26 #include <linux/platform_data/x86/apple.h> 27 #include <linux/property.h> 28 #include <linux/slab.h> 29 #include <linux/ucs2_string.h> 30 #include <asm/setup.h> 31 32 static bool dump_properties __initdata; 33 34 static int __init dump_properties_enable(char *arg) 35 { 36 dump_properties = true; 37 return 0; 38 } 39 40 __setup("dump_apple_properties", dump_properties_enable); 41 42 struct dev_header { 43 u32 len; 44 u32 prop_count; 45 struct efi_dev_path path[0]; 46 /* 47 * followed by key/value pairs, each key and value preceded by u32 len, 48 * len includes itself, value may be empty (in which case its len is 4) 49 */ 50 }; 51 52 struct properties_header { 53 u32 len; 54 u32 version; 55 u32 dev_count; 56 struct dev_header dev_header[0]; 57 }; 58 59 static void __init unmarshal_key_value_pairs(struct dev_header *dev_header, 60 struct device *dev, void *ptr, 61 struct property_entry entry[]) 62 { 63 int i; 64 65 for (i = 0; i < dev_header->prop_count; i++) { 66 int remaining = dev_header->len - (ptr - (void *)dev_header); 67 u32 key_len, val_len; 68 char *key; 69 70 if (sizeof(key_len) > remaining) 71 break; 72 73 key_len = *(typeof(key_len) *)ptr; 74 if (key_len + sizeof(val_len) > remaining || 75 key_len < sizeof(key_len) + sizeof(efi_char16_t) || 76 *(efi_char16_t *)(ptr + sizeof(key_len)) == 0) { 77 dev_err(dev, "invalid property name len at %#zx\n", 78 ptr - (void *)dev_header); 79 break; 80 } 81 82 val_len = *(typeof(val_len) *)(ptr + key_len); 83 if (key_len + val_len > remaining || 84 val_len < sizeof(val_len)) { 85 dev_err(dev, "invalid property val len at %#zx\n", 86 ptr - (void *)dev_header + key_len); 87 break; 88 } 89 90 /* 4 bytes to accommodate UTF-8 code points + null byte */ 91 key = kzalloc((key_len - sizeof(key_len)) * 4 + 1, GFP_KERNEL); 92 if (!key) { 93 dev_err(dev, "cannot allocate property name\n"); 94 break; 95 } 96 ucs2_as_utf8(key, ptr + sizeof(key_len), 97 key_len - sizeof(key_len)); 98 99 entry[i].name = key; 100 entry[i].length = val_len - sizeof(val_len); 101 entry[i].is_array = !!entry[i].length; 102 entry[i].type = DEV_PROP_U8; 103 entry[i].pointer.u8_data = ptr + key_len + sizeof(val_len); 104 105 if (dump_properties) { 106 dev_info(dev, "property: %s\n", entry[i].name); 107 print_hex_dump(KERN_INFO, pr_fmt(), DUMP_PREFIX_OFFSET, 108 16, 1, entry[i].pointer.u8_data, 109 entry[i].length, true); 110 } 111 112 ptr += key_len + val_len; 113 } 114 115 if (i != dev_header->prop_count) { 116 dev_err(dev, "got %d device properties, expected %u\n", i, 117 dev_header->prop_count); 118 print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET, 119 16, 1, dev_header, dev_header->len, true); 120 return; 121 } 122 123 dev_info(dev, "assigning %d device properties\n", i); 124 } 125 126 static int __init unmarshal_devices(struct properties_header *properties) 127 { 128 size_t offset = offsetof(struct properties_header, dev_header[0]); 129 130 while (offset + sizeof(struct dev_header) < properties->len) { 131 struct dev_header *dev_header = (void *)properties + offset; 132 struct property_entry *entry = NULL; 133 struct device *dev; 134 size_t len; 135 int ret, i; 136 void *ptr; 137 138 if (offset + dev_header->len > properties->len || 139 dev_header->len <= sizeof(*dev_header)) { 140 pr_err("invalid len in dev_header at %#zx\n", offset); 141 return -EINVAL; 142 } 143 144 ptr = dev_header->path; 145 len = dev_header->len - sizeof(*dev_header); 146 147 dev = efi_get_device_by_path((struct efi_dev_path **)&ptr, &len); 148 if (IS_ERR(dev)) { 149 pr_err("device path parse error %ld at %#zx:\n", 150 PTR_ERR(dev), ptr - (void *)dev_header); 151 print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET, 152 16, 1, dev_header, dev_header->len, true); 153 dev = NULL; 154 goto skip_device; 155 } 156 157 entry = kcalloc(dev_header->prop_count + 1, sizeof(*entry), 158 GFP_KERNEL); 159 if (!entry) { 160 dev_err(dev, "cannot allocate properties\n"); 161 goto skip_device; 162 } 163 164 unmarshal_key_value_pairs(dev_header, dev, ptr, entry); 165 if (!entry[0].name) 166 goto skip_device; 167 168 ret = device_add_properties(dev, entry); /* makes deep copy */ 169 if (ret) 170 dev_err(dev, "error %d assigning properties\n", ret); 171 172 for (i = 0; entry[i].name; i++) 173 kfree(entry[i].name); 174 175 skip_device: 176 kfree(entry); 177 put_device(dev); 178 offset += dev_header->len; 179 } 180 181 return 0; 182 } 183 184 static int __init map_properties(void) 185 { 186 struct properties_header *properties; 187 struct setup_data *data; 188 u32 data_len; 189 u64 pa_data; 190 int ret; 191 192 if (!x86_apple_machine) 193 return 0; 194 195 pa_data = boot_params.hdr.setup_data; 196 while (pa_data) { 197 data = memremap(pa_data, sizeof(*data), MEMREMAP_WB); 198 if (!data) { 199 pr_err("cannot map setup_data header\n"); 200 return -ENOMEM; 201 } 202 203 if (data->type != SETUP_APPLE_PROPERTIES) { 204 pa_data = data->next; 205 memunmap(data); 206 continue; 207 } 208 209 data_len = data->len; 210 memunmap(data); 211 212 data = memremap(pa_data, sizeof(*data) + data_len, MEMREMAP_WB); 213 if (!data) { 214 pr_err("cannot map setup_data payload\n"); 215 return -ENOMEM; 216 } 217 218 properties = (struct properties_header *)data->data; 219 if (properties->version != 1) { 220 pr_err("unsupported version:\n"); 221 print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET, 222 16, 1, properties, data_len, true); 223 ret = -ENOTSUPP; 224 } else if (properties->len != data_len) { 225 pr_err("length mismatch, expected %u\n", data_len); 226 print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET, 227 16, 1, properties, data_len, true); 228 ret = -EINVAL; 229 } else 230 ret = unmarshal_devices(properties); 231 232 /* 233 * Can only free the setup_data payload but not its header 234 * to avoid breaking the chain of ->next pointers. 235 */ 236 data->len = 0; 237 memunmap(data); 238 free_bootmem_late(pa_data + sizeof(*data), data_len); 239 240 return ret; 241 } 242 return 0; 243 } 244 245 fs_initcall(map_properties); 246