| // SPDX-License-Identifier: GPL-2.0+ |
| /* |
| * File interface for UEFI variables |
| * |
| * Copyright (c) 2020, Heinrich Schuchardt |
| */ |
| |
| #include <efi_loader.h> |
| #include <efi_variable.h> |
| #include <u-boot/crc.h> |
| |
| /* |
| * The variables efi_var_file and efi_var_entry must be static to avoid |
| * referencing them via the global offset table (section .got). The GOT |
| * is neither mapped as EfiRuntimeServicesData nor do we support its |
| * relocation during SetVirtualAddressMap(). |
| */ |
| static struct efi_var_file __efi_runtime_data *efi_var_buf; |
| static struct efi_var_entry __efi_runtime_data *efi_current_var; |
| |
| /** |
| * efi_var_mem_compare() - compare GUID and name with a variable |
| * |
| * @var: variable to compare |
| * @guid: GUID to compare |
| * @name: variable name to compare |
| * @next: pointer to next variable |
| * Return: true if match |
| */ |
| static bool __efi_runtime |
| efi_var_mem_compare(struct efi_var_entry *var, const efi_guid_t *guid, |
| const u16 *name, struct efi_var_entry **next) |
| { |
| int i; |
| u8 *guid1, *guid2; |
| const u16 *data, *var_name; |
| bool match = true; |
| |
| for (guid1 = (u8 *)&var->guid, guid2 = (u8 *)guid, i = 0; |
| i < sizeof(efi_guid_t) && match; ++i) |
| match = (guid1[i] == guid2[i]); |
| |
| for (data = var->name, var_name = name;; ++data) { |
| if (match) |
| match = (*data == *var_name); |
| if (!*data) |
| break; |
| if (*var_name) |
| ++var_name; |
| } |
| |
| ++data; |
| |
| if (next) |
| *next = (struct efi_var_entry *) |
| ALIGN((uintptr_t)data + var->length, 8); |
| |
| if (match) |
| efi_current_var = var; |
| |
| return match; |
| } |
| |
| /** |
| * efi_var_entry_len() - Get the entry len including headers & name |
| * |
| * @var: pointer to variable start |
| * |
| * Return: 8-byte aligned variable entry length |
| */ |
| |
| u32 __efi_runtime efi_var_entry_len(struct efi_var_entry *var) |
| { |
| if (!var) |
| return 0; |
| |
| return ALIGN((sizeof(u16) * (u16_strlen(var->name) + 1)) + |
| var->length + sizeof(*var), 8); |
| } |
| |
| struct efi_var_entry __efi_runtime |
| *efi_var_mem_find(const efi_guid_t *guid, const u16 *name, |
| struct efi_var_entry **next) |
| { |
| struct efi_var_entry *var, *last; |
| |
| last = (struct efi_var_entry *) |
| ((uintptr_t)efi_var_buf + efi_var_buf->length); |
| |
| if (!*name) { |
| if (next) { |
| *next = efi_var_buf->var; |
| if (*next >= last) |
| *next = NULL; |
| } |
| return NULL; |
| } |
| if (efi_current_var && |
| efi_var_mem_compare(efi_current_var, guid, name, next)) { |
| if (next && *next >= last) |
| *next = NULL; |
| return efi_current_var; |
| } |
| |
| var = efi_var_buf->var; |
| if (var < last) { |
| for (; var;) { |
| struct efi_var_entry *pos; |
| bool match; |
| |
| match = efi_var_mem_compare(var, guid, name, &pos); |
| if (pos >= last) |
| pos = NULL; |
| if (match) { |
| if (next) |
| *next = pos; |
| return var; |
| } |
| var = pos; |
| } |
| } |
| if (next) |
| *next = NULL; |
| return NULL; |
| } |
| |
| void __efi_runtime efi_var_mem_del(struct efi_var_entry *var) |
| { |
| u16 *data; |
| struct efi_var_entry *next, *last; |
| |
| if (!var) |
| return; |
| |
| last = (struct efi_var_entry *) |
| ((uintptr_t)efi_var_buf + efi_var_buf->length); |
| if (var <= efi_current_var) |
| efi_current_var = NULL; |
| |
| for (data = var->name; *data; ++data) |
| ; |
| ++data; |
| next = (struct efi_var_entry *) |
| ALIGN((uintptr_t)data + var->length, 8); |
| efi_var_buf->length -= (uintptr_t)next - (uintptr_t)var; |
| |
| /* efi_memcpy_runtime() can be used because next >= var. */ |
| efi_memcpy_runtime(var, next, (uintptr_t)last - (uintptr_t)next); |
| efi_var_buf->crc32 = crc32(0, (u8 *)efi_var_buf->var, |
| efi_var_buf->length - |
| sizeof(struct efi_var_file)); |
| } |
| |
| efi_status_t __efi_runtime efi_var_mem_ins( |
| const u16 *variable_name, |
| const efi_guid_t *vendor, u32 attributes, |
| const efi_uintn_t size1, const void *data1, |
| const efi_uintn_t size2, const void *data2, |
| const u64 time) |
| { |
| u16 *data; |
| struct efi_var_entry *var; |
| u32 var_name_len; |
| |
| var = (struct efi_var_entry *) |
| ((uintptr_t)efi_var_buf + efi_var_buf->length); |
| var_name_len = u16_strlen(variable_name) + 1; |
| data = var->name + var_name_len; |
| |
| if ((uintptr_t)data - (uintptr_t)efi_var_buf + size1 + size2 > |
| EFI_VAR_BUF_SIZE) |
| return EFI_OUT_OF_RESOURCES; |
| |
| var->attr = attributes; |
| var->length = size1 + size2; |
| var->time = time; |
| |
| efi_memcpy_runtime(&var->guid, vendor, sizeof(efi_guid_t)); |
| efi_memcpy_runtime(var->name, variable_name, |
| sizeof(u16) * var_name_len); |
| efi_memcpy_runtime(data, data1, size1); |
| efi_memcpy_runtime((u8 *)data + size1, data2, size2); |
| |
| var = (struct efi_var_entry *) |
| ALIGN((uintptr_t)data + var->length, 8); |
| efi_var_buf->length = (uintptr_t)var - (uintptr_t)efi_var_buf; |
| efi_var_buf->crc32 = crc32(0, (u8 *)efi_var_buf->var, |
| efi_var_buf->length - |
| sizeof(struct efi_var_file)); |
| |
| return EFI_SUCCESS; |
| } |
| |
| u64 __efi_runtime efi_var_mem_free(void) |
| { |
| if (efi_var_buf->length + sizeof(struct efi_var_entry) >= |
| EFI_VAR_BUF_SIZE) |
| return 0; |
| |
| return EFI_VAR_BUF_SIZE - efi_var_buf->length - |
| sizeof(struct efi_var_entry); |
| } |
| |
| /** |
| * efi_var_mem_notify_exit_boot_services() - SetVirtualMemoryMap callback |
| * |
| * @event: callback event |
| * @context: callback context |
| */ |
| static void EFIAPI __efi_runtime |
| efi_var_mem_notify_virtual_address_map(struct efi_event *event, void *context) |
| { |
| efi_convert_pointer(0, (void **)&efi_var_buf); |
| efi_current_var = NULL; |
| } |
| |
| efi_status_t efi_var_mem_init(void) |
| { |
| u64 memory; |
| efi_status_t ret; |
| struct efi_event *event; |
| |
| ret = efi_allocate_pages(EFI_ALLOCATE_ANY_PAGES, |
| EFI_RUNTIME_SERVICES_DATA, |
| efi_size_in_pages(EFI_VAR_BUF_SIZE), |
| &memory); |
| if (ret != EFI_SUCCESS) |
| return ret; |
| efi_var_buf = (struct efi_var_file *)(uintptr_t)memory; |
| memset(efi_var_buf, 0, EFI_VAR_BUF_SIZE); |
| efi_var_buf->magic = EFI_VAR_FILE_MAGIC; |
| efi_var_buf->length = (uintptr_t)efi_var_buf->var - |
| (uintptr_t)efi_var_buf; |
| |
| ret = efi_create_event(EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE, TPL_CALLBACK, |
| efi_var_mem_notify_virtual_address_map, NULL, |
| NULL, &event); |
| if (ret != EFI_SUCCESS) |
| return ret; |
| return ret; |
| } |
| |
| /** |
| * efi_var_collect_mem() - Copy EFI variables matching attributes mask from |
| * efi_var_buf |
| * |
| * @buf: buffer containing variable collection |
| * @lenp: buffer length |
| * @mask: mask of matched attributes |
| * |
| * Return: Status code |
| */ |
| efi_status_t __efi_runtime |
| efi_var_collect_mem(struct efi_var_file *buf, efi_uintn_t *lenp, u32 mask) |
| { |
| static struct efi_var_file __efi_runtime_data hdr = { |
| .magic = EFI_VAR_FILE_MAGIC, |
| }; |
| struct efi_var_entry *last, *var, *var_to; |
| |
| hdr.length = sizeof(struct efi_var_file); |
| |
| var = efi_var_buf->var; |
| last = (struct efi_var_entry *) |
| ((uintptr_t)efi_var_buf + efi_var_buf->length); |
| if (buf) |
| var_to = buf->var; |
| |
| while (var < last) { |
| u32 len = efi_var_entry_len(var); |
| |
| if ((var->attr & mask) != mask) { |
| var = (void *)((uintptr_t)var + len); |
| continue; |
| } |
| |
| hdr.length += len; |
| |
| if (buf && hdr.length <= *lenp) { |
| efi_memcpy_runtime(var_to, var, len); |
| var_to = (void *)var_to + len; |
| } |
| var = (void *)var + len; |
| } |
| |
| if (!buf && hdr.length <= *lenp) { |
| *lenp = hdr.length; |
| return EFI_INVALID_PARAMETER; |
| } |
| |
| if (!buf || hdr.length > *lenp) { |
| *lenp = hdr.length; |
| return EFI_BUFFER_TOO_SMALL; |
| } |
| hdr.crc32 = crc32(0, (u8 *)buf->var, |
| hdr.length - sizeof(struct efi_var_file)); |
| |
| efi_memcpy_runtime(buf, &hdr, sizeof(hdr)); |
| *lenp = hdr.length; |
| |
| return EFI_SUCCESS; |
| } |
| |
| efi_status_t __efi_runtime |
| efi_get_variable_mem(const u16 *variable_name, const efi_guid_t *vendor, |
| u32 *attributes, efi_uintn_t *data_size, void *data, |
| u64 *timep, u32 mask) |
| { |
| efi_uintn_t old_size; |
| struct efi_var_entry *var; |
| u16 *pdata; |
| |
| if (!variable_name || !vendor || !data_size) |
| return EFI_INVALID_PARAMETER; |
| var = efi_var_mem_find(vendor, variable_name, NULL); |
| if (!var) |
| return EFI_NOT_FOUND; |
| |
| /* |
| * This function is used at runtime to dump EFI variables. |
| * The memory backend we keep around has BS-only variables as |
| * well. At runtime we filter them here |
| */ |
| if (mask && !((var->attr & mask) == mask)) |
| return EFI_NOT_FOUND; |
| |
| if (attributes) |
| *attributes = var->attr; |
| if (timep) |
| *timep = var->time; |
| |
| if (!u16_strcmp(variable_name, u"VarToFile")) |
| return efi_var_collect_mem(data, data_size, EFI_VARIABLE_NON_VOLATILE); |
| |
| old_size = *data_size; |
| *data_size = var->length; |
| if (old_size < var->length) |
| return EFI_BUFFER_TOO_SMALL; |
| |
| if (!data) |
| return EFI_INVALID_PARAMETER; |
| |
| for (pdata = var->name; *pdata; ++pdata) |
| ; |
| ++pdata; |
| |
| efi_memcpy_runtime(data, pdata, var->length); |
| |
| return EFI_SUCCESS; |
| } |
| |
| efi_status_t __efi_runtime |
| efi_get_next_variable_name_mem(efi_uintn_t *variable_name_size, |
| u16 *variable_name, efi_guid_t *vendor, |
| u32 mask) |
| { |
| struct efi_var_entry *var; |
| efi_uintn_t len, old_size; |
| u16 *pdata; |
| |
| if (!variable_name_size || !variable_name || !vendor) |
| return EFI_INVALID_PARAMETER; |
| |
| skip: |
| len = *variable_name_size >> 1; |
| if (u16_strnlen(variable_name, len) == len) |
| return EFI_INVALID_PARAMETER; |
| |
| if (!efi_var_mem_find(vendor, variable_name, &var) && *variable_name) |
| return EFI_INVALID_PARAMETER; |
| |
| if (!var) |
| return EFI_NOT_FOUND; |
| |
| for (pdata = var->name; *pdata; ++pdata) |
| ; |
| ++pdata; |
| |
| old_size = *variable_name_size; |
| *variable_name_size = (uintptr_t)pdata - (uintptr_t)var->name; |
| |
| if (old_size < *variable_name_size) |
| return EFI_BUFFER_TOO_SMALL; |
| |
| efi_memcpy_runtime(variable_name, var->name, *variable_name_size); |
| efi_memcpy_runtime(vendor, &var->guid, sizeof(efi_guid_t)); |
| |
| if (mask && !((var->attr & mask) == mask)) { |
| *variable_name_size = old_size; |
| goto skip; |
| } |
| |
| return EFI_SUCCESS; |
| } |
| |
| void efi_var_buf_update(struct efi_var_file *var_buf) |
| { |
| memcpy(efi_var_buf, var_buf, EFI_VAR_BUF_SIZE); |
| } |