drivers/firmware/efi/apple-properties.c

   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
  18 #define pr_fmt(fmt) "apple-properties: " fmt
  19
  20 #include <linux/bootmem.h>
  21 #include <linux/dmi.h>
  22 #include <linux/efi.h>
  23 #include <linux/property.h>
  24 #include <linux/slab.h>
  25 #include <linux/ucs2_string.h>
  26 #include <asm/setup.h>
  27
  28 static bool dump_properties __initdata;
  29
  30 static int __init dump_properties_enable(char *arg)
  31 {
  32         dump_properties = true;
  33         return 0;
  34 }
  35
  36 __setup("dump_apple_properties", dump_properties_enable);
  37
  38 struct dev_header {
  39         u32 len;
  40         u32 prop_count;
  41         struct efi_dev_path path[0];
  42         /*
  43          * followed by key/value pairs, each key and value preceded by u32 len,
  44          * len includes itself, value may be empty (in which case its len is 4)
  45          */
  46 };
  47
  48 struct properties_header {
  49         u32 len;
  50         u32 version;
  51         u32 dev_count;
  52         struct dev_header dev_header[0];
  53 };
  54
  55 static u8 one __initdata = 1;
  56
  57 static void __init unmarshal_key_value_pairs(struct dev_header *dev_header,
  58                                              struct device *dev, void *ptr,
  59                                              struct property_entry entry[])
  60 {
  61         int i;
  62
  63         for (i = 0; i < dev_header->prop_count; i++) {
  64                 int remaining = dev_header->len - (ptr - (void *)dev_header);
  65                 u32 key_len, val_len;
  66                 char *key;
  67
  68                 if (sizeof(key_len) > remaining)
  69                         break;
  70
  71                 key_len = *(typeof(key_len) *)ptr;
  72                 if (key_len + sizeof(val_len) > remaining ||
  73                     key_len < sizeof(key_len) + sizeof(efi_char16_t) ||
  74                     *(efi_char16_t *)(ptr + sizeof(key_len)) == 0) {
  75                         dev_err(dev, "invalid property name len at %#zx\n",
  76                                 ptr - (void *)dev_header);
  77                         break;
  78                 }
  79
  80                 val_len = *(typeof(val_len) *)(ptr + key_len);
  81                 if (key_len + val_len > remaining ||
  82                     val_len < sizeof(val_len)) {
  83                         dev_err(dev, "invalid property val len at %#zx\n",
  84                                 ptr - (void *)dev_header + key_len);
  85                         break;
  86                 }
  87
  88                 /* 4 bytes to accommodate UTF-8 code points + null byte */
  89                 key = kzalloc((key_len - sizeof(key_len)) * 4 + 1, GFP_KERNEL);
  90                 if (!key) {
  91                         dev_err(dev, "cannot allocate property name\n");
  92                         break;
  93                 }
  94                 ucs2_as_utf8(key, ptr + sizeof(key_len),
  95                              key_len - sizeof(key_len));
  96
  97                 entry[i].name = key;
  98                 entry[i].is_array = true;
  99                 entry[i].length = val_len - sizeof(val_len);
 100                 entry[i].pointer.raw_data = ptr + key_len + sizeof(val_len);
 101                 if (!entry[i].length) {
 102                         /* driver core doesn't accept empty properties */
 103                         entry[i].length = 1;
 104                         entry[i].pointer.raw_data = &one;
 105                 }
 106
 107                 if (dump_properties) {
 108                         dev_info(dev, "property: %s\n", entry[i].name);
 109                         print_hex_dump(KERN_INFO, pr_fmt(), DUMP_PREFIX_OFFSET,
 110                                 16, 1, entry[i].pointer.raw_data,
 111                                 entry[i].length, true);
 112                 }
 113
 114                 ptr += key_len + val_len;
 115         }
 116
 117         if (i != dev_header->prop_count) {
 118                 dev_err(dev, "got %d device properties, expected %u\n", i,
 119                         dev_header->prop_count);
 120                 print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
 121                         16, 1, dev_header, dev_header->len, true);
 122                 return;
 123         }
 124
 125         dev_info(dev, "assigning %d device properties\n", i);
 126 }
 127
 128 static int __init unmarshal_devices(struct properties_header *properties)
 129 {
 130         size_t offset = offsetof(struct properties_header, dev_header[0]);
 131
 132         while (offset + sizeof(struct dev_header) < properties->len) {
 133                 struct dev_header *dev_header = (void *)properties + offset;
 134                 struct property_entry *entry = NULL;
 135                 struct device *dev;
 136                 size_t len;
 137                 int ret, i;
 138                 void *ptr;
 139
 140                 if (offset + dev_header->len > properties->len ||
 141                     dev_header->len <= sizeof(*dev_header)) {
 142                         pr_err("invalid len in dev_header at %#zx\n", offset);
 143                         return -EINVAL;
 144                 }
 145
 146                 ptr = dev_header->path;
 147                 len = dev_header->len - sizeof(*dev_header);
 148
 149                 dev = efi_get_device_by_path((struct efi_dev_path **)&ptr, &len);
 150                 if (IS_ERR(dev)) {
 151                         pr_err("device path parse error %ld at %#zx:\n",
 152                                PTR_ERR(dev), ptr - (void *)dev_header);
 153                         print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
 154                                16, 1, dev_header, dev_header->len, true);
 155                         dev = NULL;
 156                         goto skip_device;
 157                 }
 158
 159                 entry = kcalloc(dev_header->prop_count + 1, sizeof(*entry),
 160                                 GFP_KERNEL);
 161                 if (!entry) {
 162                         dev_err(dev, "cannot allocate properties\n");
 163                         goto skip_device;
 164                 }
 165
 166                 unmarshal_key_value_pairs(dev_header, dev, ptr, entry);
 167                 if (!entry[0].name)
 168                         goto skip_device;
 169
 170                 ret = device_add_properties(dev, entry); /* makes deep copy */
 171                 if (ret)
 172                         dev_err(dev, "error %d assigning properties\n", ret);
 173
 174                 for (i = 0; entry[i].name; i++)
 175                         kfree(entry[i].name);
 176
 177 skip_device:
 178                 kfree(entry);
 179                 put_device(dev);
 180                 offset += dev_header->len;
 181         }
 182
 183         return 0;
 184 }
 185
 186 static int __init map_properties(void)
 187 {
 188         struct properties_header *properties;
 189         struct setup_data *data;
 190         u32 data_len;
 191         u64 pa_data;
 192         int ret;
 193
 194         if (!dmi_match(DMI_SYS_VENDOR, "Apple Inc.") &&
 195             !dmi_match(DMI_SYS_VENDOR, "Apple Computer, Inc."))
 196                 return 0;
 197
 198         pa_data = boot_params.hdr.setup_data;
 199         while (pa_data) {
 200                 data = ioremap(pa_data, sizeof(*data));
 201                 if (!data) {
 202                         pr_err("cannot map setup_data header\n");
 203                         return -ENOMEM;
 204                 }
 205
 206                 if (data->type != SETUP_APPLE_PROPERTIES) {
 207                         pa_data = data->next;
 208                         iounmap(data);
 209                         continue;
 210                 }
 211
 212                 data_len = data->len;
 213                 iounmap(data);
 214
 215                 data = ioremap(pa_data, sizeof(*data) + data_len);
 216                 if (!data) {
 217                         pr_err("cannot map setup_data payload\n");
 218                         return -ENOMEM;
 219                 }
 220
 221                 properties = (struct properties_header *)data->data;
 222                 if (properties->version != 1) {
 223                         pr_err("unsupported version:\n");
 224                         print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
 225                                16, 1, properties, data_len, true);
 226                         ret = -ENOTSUPP;
 227                 } else if (properties->len != data_len) {
 228                         pr_err("length mismatch, expected %u\n", data_len);
 229                         print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET,
 230                                16, 1, properties, data_len, true);
 231                         ret = -EINVAL;
 232                 } else
 233                         ret = unmarshal_devices(properties);
 234
 235                 /*
 236                  * Can only free the setup_data payload but not its header
 237                  * to avoid breaking the chain of ->next pointers.
 238                  */
 239                 data->len = 0;
 240                 iounmap(data);
 241                 free_bootmem_late(pa_data + sizeof(*data), data_len);
 242
 243                 return ret;
 244         }
 245         return 0;
 246 }
 247
 248 fs_initcall(map_properties);