drivers/firmware/efi/apple-properties.c

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