| // SPDX-License-Identifier: GPL-2.0+ |
| /* |
| * EFI boot manager |
| * |
| * Copyright (c) 2017 Rob Clark |
| */ |
| |
| #include <common.h> |
| #include <charset.h> |
| #include <log.h> |
| #include <malloc.h> |
| #include <efi_loader.h> |
| #include <asm/unaligned.h> |
| |
| static const struct efi_boot_services *bs; |
| static const struct efi_runtime_services *rs; |
| |
| /* |
| * bootmgr implements the logic of trying to find a payload to boot |
| * based on the BootOrder + BootXXXX variables, and then loading it. |
| * |
| * TODO detecting a special key held (f9?) and displaying a boot menu |
| * like you would get on a PC would be clever. |
| * |
| * TODO if we had a way to write and persist variables after the OS |
| * has started, we'd also want to check OsIndications to see if we |
| * should do normal or recovery boot. |
| */ |
| |
| |
| /** |
| * efi_deserialize_load_option() - parse serialized data |
| * |
| * Parse serialized data describing a load option and transform it to the |
| * efi_load_option structure. |
| * |
| * @lo: pointer to target |
| * @data: serialized data |
| * @size: size of the load option, on return size of the optional data |
| * Return: status code |
| */ |
| efi_status_t efi_deserialize_load_option(struct efi_load_option *lo, u8 *data, |
| efi_uintn_t *size) |
| { |
| efi_uintn_t len; |
| |
| len = sizeof(u32); |
| if (*size < len + 2 * sizeof(u16)) |
| return EFI_INVALID_PARAMETER; |
| lo->attributes = get_unaligned_le32(data); |
| data += len; |
| *size -= len; |
| |
| len = sizeof(u16); |
| lo->file_path_length = get_unaligned_le16(data); |
| data += len; |
| *size -= len; |
| |
| lo->label = (u16 *)data; |
| len = u16_strnlen(lo->label, *size / sizeof(u16) - 1); |
| if (lo->label[len]) |
| return EFI_INVALID_PARAMETER; |
| len = (len + 1) * sizeof(u16); |
| if (*size < len) |
| return EFI_INVALID_PARAMETER; |
| data += len; |
| *size -= len; |
| |
| len = lo->file_path_length; |
| if (*size < len) |
| return EFI_INVALID_PARAMETER; |
| lo->file_path = (struct efi_device_path *)data; |
| /* |
| * TODO: validate device path. There should be an end node within |
| * the indicated file_path_length. |
| */ |
| data += len; |
| *size -= len; |
| |
| lo->optional_data = data; |
| |
| return EFI_SUCCESS; |
| } |
| |
| /** |
| * efi_serialize_load_option() - serialize load option |
| * |
| * Serialize efi_load_option structure into byte stream for BootXXXX. |
| * |
| * @data: buffer for serialized data |
| * @lo: load option |
| * Return: size of allocated buffer |
| */ |
| unsigned long efi_serialize_load_option(struct efi_load_option *lo, u8 **data) |
| { |
| unsigned long label_len; |
| unsigned long size; |
| u8 *p; |
| |
| label_len = (u16_strlen(lo->label) + 1) * sizeof(u16); |
| |
| /* total size */ |
| size = sizeof(lo->attributes); |
| size += sizeof(lo->file_path_length); |
| size += label_len; |
| size += lo->file_path_length; |
| if (lo->optional_data) |
| size += (utf8_utf16_strlen((const char *)lo->optional_data) |
| + 1) * sizeof(u16); |
| p = malloc(size); |
| if (!p) |
| return 0; |
| |
| /* copy data */ |
| *data = p; |
| memcpy(p, &lo->attributes, sizeof(lo->attributes)); |
| p += sizeof(lo->attributes); |
| |
| memcpy(p, &lo->file_path_length, sizeof(lo->file_path_length)); |
| p += sizeof(lo->file_path_length); |
| |
| memcpy(p, lo->label, label_len); |
| p += label_len; |
| |
| memcpy(p, lo->file_path, lo->file_path_length); |
| p += lo->file_path_length; |
| |
| if (lo->optional_data) { |
| utf8_utf16_strcpy((u16 **)&p, (const char *)lo->optional_data); |
| p += sizeof(u16); /* size of trailing \0 */ |
| } |
| return size; |
| } |
| |
| /** |
| * get_var() - get UEFI variable |
| * |
| * It is the caller's duty to free the returned buffer. |
| * |
| * @name: name of variable |
| * @vendor: vendor GUID of variable |
| * @size: size of allocated buffer |
| * Return: buffer with variable data or NULL |
| */ |
| static void *get_var(u16 *name, const efi_guid_t *vendor, |
| efi_uintn_t *size) |
| { |
| efi_guid_t *v = (efi_guid_t *)vendor; |
| efi_status_t ret; |
| void *buf = NULL; |
| |
| *size = 0; |
| EFI_CALL(ret = rs->get_variable(name, v, NULL, size, buf)); |
| if (ret == EFI_BUFFER_TOO_SMALL) { |
| buf = malloc(*size); |
| EFI_CALL(ret = rs->get_variable(name, v, NULL, size, buf)); |
| } |
| |
| if (ret != EFI_SUCCESS) { |
| free(buf); |
| *size = 0; |
| return NULL; |
| } |
| |
| return buf; |
| } |
| |
| /** |
| * try_load_entry() - try to load image for boot option |
| * |
| * Attempt to load load-option number 'n', returning device_path and file_path |
| * if successful. This checks that the EFI_LOAD_OPTION is active (enabled) |
| * and that the specified file to boot exists. |
| * |
| * @n: number of the boot option, e.g. 0x0a13 for Boot0A13 |
| * @handle: on return handle for the newly installed image |
| * Return: status code |
| */ |
| static efi_status_t try_load_entry(u16 n, efi_handle_t *handle) |
| { |
| struct efi_load_option lo; |
| u16 varname[] = L"Boot0000"; |
| u16 hexmap[] = L"0123456789ABCDEF"; |
| void *load_option; |
| efi_uintn_t size; |
| efi_status_t ret; |
| |
| varname[4] = hexmap[(n & 0xf000) >> 12]; |
| varname[5] = hexmap[(n & 0x0f00) >> 8]; |
| varname[6] = hexmap[(n & 0x00f0) >> 4]; |
| varname[7] = hexmap[(n & 0x000f) >> 0]; |
| |
| load_option = get_var(varname, &efi_global_variable_guid, &size); |
| if (!load_option) |
| return EFI_LOAD_ERROR; |
| |
| ret = efi_deserialize_load_option(&lo, load_option, &size); |
| if (ret != EFI_SUCCESS) { |
| log_warning("Invalid load option for %ls\n", varname); |
| goto error; |
| } |
| |
| if (lo.attributes & LOAD_OPTION_ACTIVE) { |
| u32 attributes; |
| |
| debug("%s: trying to load \"%ls\" from %pD\n", |
| __func__, lo.label, lo.file_path); |
| |
| ret = EFI_CALL(efi_load_image(true, efi_root, lo.file_path, |
| NULL, 0, handle)); |
| if (ret != EFI_SUCCESS) { |
| printf("Loading from Boot%04X '%ls' failed\n", n, |
| lo.label); |
| goto error; |
| } |
| |
| attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS | |
| EFI_VARIABLE_RUNTIME_ACCESS; |
| size = sizeof(n); |
| ret = EFI_CALL(efi_set_variable( |
| L"BootCurrent", |
| (efi_guid_t *)&efi_global_variable_guid, |
| attributes, size, &n)); |
| if (ret != EFI_SUCCESS) { |
| if (EFI_CALL(efi_unload_image(*handle)) |
| != EFI_SUCCESS) |
| printf("Unloading image failed\n"); |
| goto error; |
| } |
| |
| printf("Booting: %ls\n", lo.label); |
| } else { |
| ret = EFI_LOAD_ERROR; |
| } |
| |
| error: |
| free(load_option); |
| |
| return ret; |
| } |
| |
| /** |
| * efi_bootmgr_load() - try to load from BootNext or BootOrder |
| * |
| * Attempt to load from BootNext or in the order specified by BootOrder |
| * EFI variable, the available load-options, finding and returning |
| * the first one that can be loaded successfully. |
| * |
| * @handle: on return handle for the newly installed image |
| * Return: status code |
| */ |
| efi_status_t efi_bootmgr_load(efi_handle_t *handle) |
| { |
| u16 bootnext, *bootorder; |
| efi_uintn_t size; |
| int i, num; |
| efi_status_t ret; |
| |
| bs = systab.boottime; |
| rs = systab.runtime; |
| |
| /* BootNext */ |
| bootnext = 0; |
| size = sizeof(bootnext); |
| ret = EFI_CALL(efi_get_variable(L"BootNext", |
| (efi_guid_t *)&efi_global_variable_guid, |
| NULL, &size, &bootnext)); |
| if (ret == EFI_SUCCESS || ret == EFI_BUFFER_TOO_SMALL) { |
| /* BootNext does exist here */ |
| if (ret == EFI_BUFFER_TOO_SMALL || size != sizeof(u16)) |
| printf("BootNext must be 16-bit integer\n"); |
| |
| /* delete BootNext */ |
| ret = EFI_CALL(efi_set_variable( |
| L"BootNext", |
| (efi_guid_t *)&efi_global_variable_guid, |
| EFI_VARIABLE_NON_VOLATILE, 0, |
| &bootnext)); |
| |
| /* load BootNext */ |
| if (ret == EFI_SUCCESS) { |
| if (size == sizeof(u16)) { |
| ret = try_load_entry(bootnext, handle); |
| if (ret == EFI_SUCCESS) |
| return ret; |
| printf("Loading from BootNext failed, falling back to BootOrder\n"); |
| } |
| } else { |
| printf("Deleting BootNext failed\n"); |
| } |
| } |
| |
| /* BootOrder */ |
| bootorder = get_var(L"BootOrder", &efi_global_variable_guid, &size); |
| if (!bootorder) { |
| printf("BootOrder not defined\n"); |
| ret = EFI_NOT_FOUND; |
| goto error; |
| } |
| |
| num = size / sizeof(uint16_t); |
| for (i = 0; i < num; i++) { |
| debug("%s: trying to load Boot%04X\n", __func__, bootorder[i]); |
| ret = try_load_entry(bootorder[i], handle); |
| if (ret == EFI_SUCCESS) |
| break; |
| } |
| |
| free(bootorder); |
| |
| error: |
| return ret; |
| } |