/* * apple-properties.c - EFI device properties on Macs * Copyright (C) 2016 Lukas Wunner * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License (version 2) as * published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . * * Note, all properties are considered as u8 arrays. * To get a value of any of them the caller must use device_property_read_u8_array(). */ #define pr_fmt(fmt) "apple-properties: " fmt #include #include #include #include #include #include #include #include static bool dump_properties __initdata; static int __init dump_properties_enable(char *arg) { dump_properties = true; return 0; } __setup("dump_apple_properties", dump_properties_enable); struct dev_header { u32 len; u32 prop_count; struct efi_dev_path path[0]; /* * followed by key/value pairs, each key and value preceded by u32 len, * len includes itself, value may be empty (in which case its len is 4) */ }; struct properties_header { u32 len; u32 version; u32 dev_count; struct dev_header dev_header[0]; }; static void __init unmarshal_key_value_pairs(struct dev_header *dev_header, struct device *dev, void *ptr, struct property_entry entry[]) { int i; for (i = 0; i < dev_header->prop_count; i++) { int remaining = dev_header->len - (ptr - (void *)dev_header); u32 key_len, val_len; char *key; if (sizeof(key_len) > remaining) break; key_len = *(typeof(key_len) *)ptr; if (key_len + sizeof(val_len) > remaining || key_len < sizeof(key_len) + sizeof(efi_char16_t) || *(efi_char16_t *)(ptr + sizeof(key_len)) == 0) { dev_err(dev, "invalid property name len at %#zx\n", ptr - (void *)dev_header); break; } val_len = *(typeof(val_len) *)(ptr + key_len); if (key_len + val_len > remaining || val_len < sizeof(val_len)) { dev_err(dev, "invalid property val len at %#zx\n", ptr - (void *)dev_header + key_len); break; } /* 4 bytes to accommodate UTF-8 code points + null byte */ key = kzalloc((key_len - sizeof(key_len)) * 4 + 1, GFP_KERNEL); if (!key) { dev_err(dev, "cannot allocate property name\n"); break; } ucs2_as_utf8(key, ptr + sizeof(key_len), key_len - sizeof(key_len)); entry[i].name = key; entry[i].length = val_len - sizeof(val_len); entry[i].is_array = !!entry[i].length; entry[i].type = DEV_PROP_U8; entry[i].pointer.u8_data = ptr + key_len + sizeof(val_len); if (dump_properties) { dev_info(dev, "property: %s\n", entry[i].name); print_hex_dump(KERN_INFO, pr_fmt(), DUMP_PREFIX_OFFSET, 16, 1, entry[i].pointer.u8_data, entry[i].length, true); } ptr += key_len + val_len; } if (i != dev_header->prop_count) { dev_err(dev, "got %d device properties, expected %u\n", i, dev_header->prop_count); print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET, 16, 1, dev_header, dev_header->len, true); return; } dev_info(dev, "assigning %d device properties\n", i); } static int __init unmarshal_devices(struct properties_header *properties) { size_t offset = offsetof(struct properties_header, dev_header[0]); while (offset + sizeof(struct dev_header) < properties->len) { struct dev_header *dev_header = (void *)properties + offset; struct property_entry *entry = NULL; struct device *dev; size_t len; int ret, i; void *ptr; if (offset + dev_header->len > properties->len || dev_header->len <= sizeof(*dev_header)) { pr_err("invalid len in dev_header at %#zx\n", offset); return -EINVAL; } ptr = dev_header->path; len = dev_header->len - sizeof(*dev_header); dev = efi_get_device_by_path((struct efi_dev_path **)&ptr, &len); if (IS_ERR(dev)) { pr_err("device path parse error %ld at %#zx:\n", PTR_ERR(dev), ptr - (void *)dev_header); print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET, 16, 1, dev_header, dev_header->len, true); dev = NULL; goto skip_device; } entry = kcalloc(dev_header->prop_count + 1, sizeof(*entry), GFP_KERNEL); if (!entry) { dev_err(dev, "cannot allocate properties\n"); goto skip_device; } unmarshal_key_value_pairs(dev_header, dev, ptr, entry); if (!entry[0].name) goto skip_device; ret = device_add_properties(dev, entry); /* makes deep copy */ if (ret) dev_err(dev, "error %d assigning properties\n", ret); for (i = 0; entry[i].name; i++) kfree(entry[i].name); skip_device: kfree(entry); put_device(dev); offset += dev_header->len; } return 0; } static int __init map_properties(void) { struct properties_header *properties; struct setup_data *data; u32 data_len; u64 pa_data; int ret; if (!x86_apple_machine) return 0; pa_data = boot_params.hdr.setup_data; while (pa_data) { data = memremap(pa_data, sizeof(*data), MEMREMAP_WB); if (!data) { pr_err("cannot map setup_data header\n"); return -ENOMEM; } if (data->type != SETUP_APPLE_PROPERTIES) { pa_data = data->next; memunmap(data); continue; } data_len = data->len; memunmap(data); data = memremap(pa_data, sizeof(*data) + data_len, MEMREMAP_WB); if (!data) { pr_err("cannot map setup_data payload\n"); return -ENOMEM; } properties = (struct properties_header *)data->data; if (properties->version != 1) { pr_err("unsupported version:\n"); print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET, 16, 1, properties, data_len, true); ret = -ENOTSUPP; } else if (properties->len != data_len) { pr_err("length mismatch, expected %u\n", data_len); print_hex_dump(KERN_ERR, pr_fmt(), DUMP_PREFIX_OFFSET, 16, 1, properties, data_len, true); ret = -EINVAL; } else ret = unmarshal_devices(properties); /* * Can only free the setup_data payload but not its header * to avoid breaking the chain of ->next pointers. */ data->len = 0; memunmap(data); free_bootmem_late(pa_data + sizeof(*data), data_len); return ret; } return 0; } fs_initcall(map_properties);